geol. croat . 50/2 299 zagreb 1997 hydrologic evolution of a carbonate aquifer (dinaric karst, croatia) lj ubomir babic' . damir lackovic' and nada horva tincic' dinaric karst terrains contain specific, lam inated speleothems, which line all surfaces of subterranean voids including cretaceous bedrock limestone, and old­ er vadose speleothems and clastic sed iments. these speleothems may attain a thickness of one metre. depo­ si tion of these spe leothems took place during a 10ng­ term phreatic period in the late quaternary. this is in cont rast to well-known, widespread speleothems, which were, and are deposited in vadose and uppermost phre­ atic settings. furthermore, the origin of these phreatic speleothems departs from common experience by the domi nan t di ssoluti onal w ideriing of underground coni depa rtment of geo logy and palaeontology, faculty of sc ience, uni versity of zagrcb. ui. kralja zvo nimira 8, hrioooo zag reb , croatia. 2 rud er boskovic instit llte, bijcni cka ccs ta 54, hri 0000 zagreb, croati a. duils when saturated. phreatic speleothems can be imp­ ortant strat igraphic marker for the stratigraphy of cave sediments. this approach revealed a sequence of three hydrologic stages: ( i) pre-phreatic stage wi th dominant vadose condi tions and dissolution processes, (2) phreat­ ic stage when the ground-water level was very high in the large karst area, and when the volume of the voids decreased, and (3) the last , dominantly vadose stage during which voids were enlarged for the second time, and phreatic speleothems may be covered by younger clastics and vadose speleothems. this abstract was presented at the scientific meeting dedicated to the 80th anniversary of the life of professor milan herak, held on march 5th, 1997 in zagreb ljcologla lro;ilica )u/l geol . c roat. 49/2 327 zagreb 1996 ahsfrac! nole the interpretation of seismic and geological data of some structures in albania ahmc( c;:ollaku based on ex is ting seism ic data , an interpre tat ion is sugges ted ror the two remaini ng partially unex plored areas in the kruja and ion ian tectonic zone in alban ia. the pck isht -pcqin-galush zone is located to the wes t o r the dunnca diapir and extends 15 km in the meridian d irec tion covering an a rea of approx imate ly 100 kill:!. the tortonian and palaeogene limestone de posi ts re present the main objects for exp loration. tn the pck isht zone the re arc oil pool s at depths of approx­ imat e ly 1000 ill. a number or exploratory wells a lso ex is t, with an average depth of 3000 j11 bu t these were ilot s ited in adequate and/or favourable struc tural condi ­ tions. the molasse and palaeogene deposi ts continue to the cas t and west in a tongue-like form with pinch-o lit s and bays producing fa vourabl e condi tions 1'01' o il accu­ mulation. thcsc depos its arc eilher transgressive o r or tecton ic origi n and a rc cons idered to have significant potential for accum ulation of oi l. the inte rpretat ion or the seismic proriles clearly confi rms the ovenhrust ing o r the dulllrea di api r in a westward direc ti on. t his ove rth rus ting wit h a magnitude of severa l kilo me tres ha~ caused the masking of st ructures of the ionian zone. decreasing thickness or the molasse dcposit s is reg is­ tered cas t ward. the possibil ity of hydrocarbon accu mu­ lation in tlte flanks of the diapiric sa lt domes illllst also be considered . the se ism ics in thi s zone wl;rc shot be tween 1989 and 1992 as part of an extensive study or the dulllrca diapir. thc lines arc comparatively short, very di s tant from each other and with no intersec ti ons a lbsics, a lbpclrol. ri cr , a lbania. proceedings whi ch, together with the varia tion o r the weathe r ing parameters, makes interpretat ion very difficult. the paper-rove-y1ezezi zone is located to the north of the dulllrea d iapir and is composed of th rust be lts wit h fl ysch, fol ding wes twa rd. the ca rbonate mo un­ tains are exposed in the eas tern pnrt of the mea. the 40 km long zone ex te nd s in a me ridi onal direction and covers an area of 300 km 2 . a few wells arc drilled , but were located outside thc prospect zones . apa rt from these wells, the area can be cons ide red to be st ill rela­ tive ly unexplored, with poss ibilities j"or the discovery of oil and gas pools. the structures arc tectonically super­ imposed and the outcroppin g neogene depos it s are overlying the older st rata. the acquisi ti on or seismic data in thi s a rea bega n in 1970. the rugged terrain , togethe r wit h variations of the wcnthering zone parame­ ters, ncgative ly influenced the quali ty or the recorded data. it was main ly the magnetic record ing sys tem that was used (95% of the profiles) and on ly a number of more recently shot lincs (5%) arc in a d ig ital recorded form . there fore, the desc ribcd system is not only char­ ac te ri sed by irregul a r coverage, but is also no t a un i­ rofm one. three conclusions may be d raw n. firs tl y, both zones a rc in adequate ly covered by se ismi c elata. sec­ ond ly, st rong lateral and verti ca l velocity g radi e nts ex ist , and thirdly , one can not overcll1phasise the impor­ tancc of reprocessing of the seismic i inc. geologia cro:ltica 49(2 geol . c roat. 49/2 329 zagreb 1996 ahsrract note geological, geophysical and geochemical data in the oil exploration of central adriatic area danko drechsler ', edita balaz-boromisa', mario sustercu: ' and anda alajbeg2 the dinaricles mesozoic carbonate platfo rm consti ­ tutes an ex tensive palaeogeographic un it of the nco­ tethys p lat form system. t he large sedimentary co ill ­ plex wi thin the p la tform di sp lays good hydrocarbon potent ial. /\ de tailed s tudy of the lates t geological data from the ka mali block and other relevant areas is based on the follow ing e lements: slnhig raphi c evolution linked to structural history; definiti on of potential source rocks , their stratigraphic and geographic exten t; palac: ol cc lon ic contro l of variolls depositional envi ­ ronm ent s . these range from extremely res tri c ted (anox ic) conditions, to high energy zones on the plat ­ form marg ins and the edges of intraplatform basins and lagoons; difterent ial platform subsidence and burial of poten­ ti a l source rocks during ptmform evolution and post p[a tfol1n fl ysch and mol asse sed imcntation; the d is tribution of reservoirs and sea ls; the locati on of traps and the timing o f thei r develop­ ment in re lation to the liming of hydrocarbon gene ra­ tion and migration. the complex geological sett ing or the area required detailed struc tural ana lysi s, to provide the base ror con­ stru c ti o n or balanced geological cros s sec tion s. the genc ra l na ture or geo logical maps , the scal e and ihe data qu oted the rein , were insufficient for that purpose. to enable beller understanding of the struc tural concept o f the mea, sa tellite data were introduced. landsa t scannograms at scale i :50.000 cove ring the central adriatic and adjaccnt areas wcre anal ysed . the da ta were recorded by la iosat-5 sate llite, using the thematic mapper technique (ti\1 ). the tm scanne r reco rds a wide spectre of visible and nca r infrared wavelengths, on 7 spectral channels (16 de tec tors e3ch) at an e levation of 700 km. the data arc di gitally trans­ millcd to earth and processed by computer. struc tura l interprctation or the area based on land­ sat tm analys is inc luded all available data; the base i ina-n;dbplin, subiccva 29, hr[0000 zagreb. croali a. proceedings geological map, wel l elata, published art ic les and fie ld e1arirication of several details. the s truc tura l e lements were out lined and by observing the nature or the ir con­ tacl s, it was possible to antic ipa te the pos ition o r th rust faulls and the direction of the ir strike. the inte rp re tation e nab led us to follo w the regional s truc tu ra l pattc rn , dctermine changes in struc tu ral trends, to rank structura l e lcmcnts regarding the ir length , and de fine changcs in the sense of structural deformati on. land sat t m inte r­ pre tation of the area on-shore, toge ther with the inte r­ pre tation of off-shore seism ic data , resul ted in the con­ struc tion of new structural map of the exploration area. geochemistry confirmed or deni ed the prediction s of source availability, of the ir depositional environment , whether tlley were oil prone and the ir maturity. it eluc i­ dated the genc ti c re lationsh ip be tween the ke roge ns, bitumens, oils and oi l seeps in the expl orati on area as we ll as explaining the consequences o r biodegradatio n. organi c geochemi stry enablcd the identification o r triassic , jurassic and cre taceous source rocks. sterane aromatizal ion and porphyrine matu rity parame te rs offe red re liable indicati ons of the reac hed ma turit y rank. hopancs distribution were used to de te rmine thc ell and gammacerane for the hype rsa line depos itional environment. accord ing to [he s tearans and mas di stributions , 8,ecompani ed by bc isotope data , the explored hydro ­ carbon s were posi ti ve ly di stin guished and asc ribed to the relevant sourcc rock. the low molecular hydrocarbons in well s, as we ll as tile bitumen in cores and outc rops, were fo und to cxhi ­ bit littl e e ffect of biodegradati o n. oil seeps suffe red severe biodegradation. the re lation of s te ranc aromati ­ zat ion to arlo allowed the de te rminat io n o r viscos ity which the biodeg radcd hydrocarbons would have had if they were preserved. the in te rp re tcd data , especially whe n integrated , present a reliable basis 1'01' the prediction o f explorati on risk and potential in the studied o il gene rati ve basin. ~ ina research & development savska 41 /1 0, hr[()(x)o zagreb, croal ia. .i.\(l geo.cro.2-3-61-kb.pdf 341 � patrick génot1, jean-paul saint-martin2 and ioan i. bucur3 ab stra ct three fragments of reproductive caps have been discovered in the sarmatian limestones of tinnye (hungary). they are assigned to the genus acetabularia (polyphysaceae, formerly acetabulariaceae). two of these fragments are quite well preserved with nine rays each. one specimen bears distinct spines at the outer ends of long rays, whereas another one has short rays with rounded outer ends and, possibly, a partially preserved corona. the third fragment is characterized by very elongated rays containing numerous gametangia. keywor ds: calcareous algae, dasycladales, polyphysaceae, acetabularia, sarmatian, hungary 1 laboratoire de planétologie et géodynamique, université de nantes, 2 rue de la houssinière, 44322 nantes cédex, france; (patrick.genot@univ-nantes.fr) 2 département histoire de la terre, muséum national d’histoire naturelle, umr 5143, 8 rue buffon, 75005 paris, france; (jpsmart@mnhn.fr) 3 department of geology, babes-bolyai university, str. m. kogalniceanu, 1, 3400 cluj-napoca, romania; (ibucur@bioge.ubbcluj.ro) polyphysaceae fertile caps in hungarian sarmatian sediments geologia croatica 61/2–3 341–344 7 figs. zagreb 2008 geologia croaticageologia croatica � 1. introduction the polyphysaceae (dasycladales) studied in this paper were discovered in the upper sarmatian tinnye formation, defi ned at tinnye, a village located in the zsámbék basin, about 30 km west of budapest (fig. 1). specimens have been found in limestones with oolitic grapestones, microbial features encrustations and crustose foraminifera, within oolitic sandstones series (fig. 2). due to rarity of these fossils, their occurrence merits description and illustration. there is a pattern of large oolitic and bioclastic shoals in the zsámbék basin, on top of which bio-constructed facies and encrustations developed. calcareous algae are associated with bivalves (obsoletiforma, paphia, tapes), gastropods (granulolabium, pirenella, clithon), foraminifera (elphidium, miliolids, nubecularids) and serpulids. the facies indicates a shallow water environment but the discussion is open with regard to salinity (harzhauser & piller, 2004). isotopic analysis undertaken on molluscs shells seems to reveal brackish infl uences, or even fresh water ones (moissette, pers. comm., 2008). 2. palaeontological description specimens from tynnie consist of three fragments of fertile caps lying on a limestone surface. two of them are quite well preserved with nine cap rays fi rmly held together by strong calcifi cation. specimen 1 (fig. 3) nine cap rays can be observed on this specimen. the entire cap of the living alga was probably composed of 14 rays. the most remarkable feature of this species is the distinct spines at the outer ends of the rays. the gametangia are not visible. diameter of the cap: 4.45 mm. length of the rays: 1.75–2 mm (approximate data because of the poor preservation of the cap central zone). maximum width of the rays: 0.75–0.90 mm. specimen 2 (fig.4) the fragment of this small cap is composed of nine rays. the estimated initial number of rays is 14 or 15. cap rays are short. their outer ends seem more or less rounded but it is not posgeologia croatica geologia croatica 61/2–3 342 sible to confi rm this because of the poor preservation of the peripheral outline of the cap. for the same reason, it is diffi cult to know if the circular swelling, located at the proximal ends of the rays, in the central area of the cap, is a partially preserved corona. longitudinal sections of three rays show 5 to 8 hemispherical cavities corresponding to the location of the gametangia. there are only 2 to 3 laterally juxtaposed game tangia in the widest part of the ray. the estimated number of gametangia inside each fertile organ is 8 to10 (but may be 16–20 if gametangia were arranged in 2 superimposed planes, that are diffi cult to determine on the specimen). diameter of the cap: 2.8 mm. length of the rays: 1.07–1.14 mm. maximum width of the rays: 0.51–0.56 mm. diameter of the central zone: 0.6 mm. diameter of gametangia: 0.16–0.18 mm. specimen 3 (fig.5) the third specimen is composed of fi ve very partially preserved cap rays. it looks different from the previous one: rays are elongated and contain numerous rounded gametangia, probably more than 40 in each organ. there are 4 to 5 laterally juxtaposed gametangia in the widest part of the ray. approximative length of the rays: at least 2.6 mm. maximum width of the rays: at least 1.1 mm (only 2 rays can be measured). diameter of gametangia: 0.20–0.23 mm. 3. generic attribution we adopt here the generic concepts recently defi ned by berger et al. (2003), after a detailed study of the phylogeny and evolution of cap development in living polyphysaceae (formerly acetabulariaceae). using a combination of morphological, developmental and molecular characteristics, the authors consider acicularia as “…completely identical in its morphology with acetabularia” and show that earlier stages of cap development are very similar in both genera. the only difference concerns the calcifi cation: gametangia are embedded into a lime matrix in acicularia, whereas gametangia are uncalcifi ed and free in acetabularia, but the authors demonstrate that lime-embedding of gametangia is in fact, a late developmental event of maturing caps. therefore, they assign the living acicularia species (a. schenckii) to the genus acetabularia. they also propose two subgenera within acetabularia: acicularia, containing all species of acetabularia, except a. aceta bulum, with the following defi nition: “unfused cap primordia”, and fi gu re 2: oolitic sandstones series of tinnye. fi gu re 3: specimen 1 – external view of a partially preserved cap. fi gu re 1: location of the zsámbék basin. geologia croaticapatrick génot et al.: polyphysaceae fertile caps in hungarian sarmatian sediments 343 acetabularia, containing a. acetabulum, characte rized by “congenitally fused cap primordia”. there is no mention of the calcifi cation in these defi nitions. so, acetabularia is now the only genus of the recent polyphy saceae (formerly acetabulariaceae) including species bearing fertile caps with gametangia embedded into a lime matrix (fig. 6). if palaeontologists adopt these new generic concepts, it would be coherent to assign all fossil species of acicularia to the genus acetabularia. this is why the three fertile caps studied in this paper are considered as acetabularia. associated rays forming caps are also known in the following genera: – orioporella morellet & morellet, characterized by its hollow caps with perforated walls and partially calcifi ed gametangia; – chalmasia solms-laubach, with strongly calcifi ed gametangia but which are free inside the rays; – parvocaulis berger et al., with uncalcifi ed ga metangia. another feature may be observed in these genera (fig. 6): the presence of lower and upper coronae in acetabularia, a corona only on the upper side of the cap in parvocaulis and chalmasia. but this morphological characteristic is almost never observed on fossils, even when the specimens fi gu re 4: specimen 2 – external and internal views of a partially preserved cap. fi gu re 5: specimen 3 – location of gametangia inside two cap rays. fi gu re 6: some features of caps in present-day polyphysaceae (data from valet, 1969; berger & kaever, 1992; berger et al., 2003; berger, 2006). geologia croatica geologia croatica 61/2–3 344 may be entirely isolated from the sediment (genot, 1987). the corona zone is often badly preserved and when the specimens are lying on a limestone surface, only one side of the cap can be studied (morellet, 1939). this is the case for specimen 2. 4. comparisons polyphysaceae fertile caps have already been discovered in sarmatian limestones from hungary, near ecseg (boda, 1959). the author assigned to a new species, acicularia conica, different specimens which, in fact, belong to distinct species (see the discussion in bucur et al., 1993). among these specimens, two of them are reproductive caps lying on a limestone surface (ibid., pl. 44, fi g. 1–2). the most complete specimen is an entire cap composed of 25 rays. the rays look much more elongated, compared with our specimens 1 and 2. unfortunately, the comparison cannot go further because the outline of the caps is badly preserved and the internal aspect of the rays remains unknown. the presence of spines at the distal ends of the rays, observed on specimen 1, is known in present-day species, such as acetabularia crenulata lamouroux, a. dentata solms-laubach (fig. 7a) and a. kilneri agardh (fig. 7b). but this is the only common feature with the sarmatian caps: the rays are much more elongated in a. crenulata and a. kilneri (valet, 1969; berger & kaever, 1992; berger, 2006). specimen 2 bears, at the centre of the cap, a fragment of a circular swelling which might be a corona. despite the exceptional occurrence of this feature on fossils, it has already been possible to describe a rather well preserved corona on sarmatian acetabulariaceae from romania (génot et al., 2002) with the characteristic protuberances (ibid., pl. iii, fi g.2) on which branched sterile hairs develop in living representatives. these protuberances are unknown on the hungarian specimen. concerning the cap rays, only one romanian specimen (ibid., pl.iii, fi g.1) has similarities with specimen 2: short rays containing a small number of gametangia. 5. conclusion hungarian specimens from tinnye probably belong to acetabularia, because of the strong calcifi cation fi lling the spaces between the gametangia. this type of calcifi cation is unknown inside the fertile caps of the other genera of poly physaceae. concerning the specifi c attribution of these three specimens, we consider that is not possible, with a so small number of partially preserved fossil caps, to determine if they may be assigned to previously described species or if they correspond to new ones. thus, more samples would be necessary to precisely establish the morphological features of these species, so as to avoid future confusion in the literature. acknowledgement the specimens of polyphysaceae described here were sampled during fi eld exploration with p. moissette, j. j. cornée (umr 5125, lyon university), a. dulai (hungarian natural history museum, budapest) and m. kazmér (eötvös university, budapest). we are grateful to a. barreau and a. cossard (nantes university) for their technical assistance in the realization of the drawings and the sem photos. we also thank b. granier for his review and for improving this paper. references berger, s., fettweiss, u., gleissberg, s., liddle, l., richter, u., sawitzky, h. & zuccarello, g. (2003): 18s rdna phylogeny and evolution of cap development in polyphysaceae (formerly acetabulariaceae; dasycladales, chlorophyta). – phycologia, 42/5, 506–561. berger, s. (2006): photo-atlas of living dasycladales. – carnets de géologie, 2006/02, 348 p. (http : //paleopolis.rediris.es/cg/cg2006_ book_02/). boda, j. (1959): algae. – in: das sarmat in ungarn und seine invertebraten-fauna. ann. inst. geol. publ. hung., 47/3, 749–752. bucur, i.i., nicorici, e. & suraru, n. (1993): sarmatian calcareous algae from rumania. – in : barattolo, f., de castro, p. & parente m. (ed.): studies on fossil benthic algae. boll. soc. paleont. ital., spec. vol. 1, 81–91. génot, p. (1987): les chlorophycées calcaires du paléogène d’europe nord-occidentale – bassin de paris, bretagne, cotentin, bassin de mons. – thesis, nantes (france), 500 p. génot, p., ionesi, v. & bucur, i. i. (2002): preliminary results from the study of acetabulariaceae fertile caps discovered in sarmatian sediments from moldavia (rumania). – in: bucur, i.i. & filipescu, s.(ed): research advances in calcareous algae and microbial carbonates. cluj university press, 95–101. harzhauser, m. & piller, w. e. (2004): integrated stratigraphy of the sarmatian (upper middle miocene) in the western central paratethys. – stratigraphy, 1/1, 1–22. morellet, l.& j. (1939) : sur une nouvelle espèce d’acicularia du sarmatien moyen d’azam, iran septentrional. – eclog. geol. helv., 32/1, 31–32. valet, g. (1969): contribution à l’étude des dasycladales. – nova hedwigia, 17, 551–644. manuscript received february 27, 2008 revised manuscript accepted may 19, 2008 fi gu re 7: reproductive caps of living acetabularia dentata (a) and a. kilneri (b) (berger & kaever, 1992, modifi ed; berger, 2006) na putu iz ljubljane u sopron u maarskoj na pancardi skup u beëkome je novome mjestu iznenada 18. rujna 2001. god., u 70. godini æivota preminuo poznati slovenski i bosansko-hercegovaëki geolog dr. sc. pero mioë. malo je tko izvan obiteljskoga kruga znao da pok. pero boluje od opasne bolesti, a poznavajuêi ga kao aktivnoga i dinamiënoga geoznanstvenika i nakon sluæbenoga odlaska u mirovinu tim viπe je za kolege, prijatelje i poznanike u hrvatskoj bila potresna vijest o njegovoj smrti. æivotni put pok. pere mioëa, kao uostalom i mnogobrojnih bosanskohercegovaëkih hrvata njegove generacije u ondaπnjoj komunistiëkoj jugoslaviji, bio je obiljeæen svakojakim teπkoêama i nadasve mukotrpnim radom, kako tijekom πkolovanja tako i u geoloπkoj karijeri. roen je 19. studenoga 1931. god u livnu, bih, gdje je zavrπio puëku πkolu i niæu gimnaziju. zanimajuêi se za rude i stijene, kojima mu je rodni kraj obilovao (osobito boksitom i ugljenom), πkolovanje nastavlja u geoloπkom tehnikumu u panëevu, srbija, jedinoj srednjoj geoloπkoj πkoli u tadaπnjoj dræavi, koju zavrπava 1951. nakon sluæenja vojske (1952.) zaposlio se je kao geoloπki tehniëar u geoloπkome zavodu bih u sarajevu. radio je na leæiπtima obojenih metala na podruëjima srebrenice, borovice, vareπa, »evljanoviêa, foëe, mraëaja i fojnice. studij praktiëne geologije na univerzi u ljubljani upisao je 1955., kojega je apsolvira 1959. od tada pa do diplomiranja 1964. radio je u spomenutim terenima u bosni, posebno u dijelu ofiolitne zone u podruëju viπegrada, a 1960. i 1961. boravio je u njemaëkoj i usa. godine 1962. zaposlio se je u geoloπkome zavodu slovenije u ljubljani u kojemu je kontinuirano radio punih 35 godina do sluæbenoga odlaska u mirovinu 1997. god. radeêi u geoloπkome zavodu na razliëitim projektima i razliëitim struënim i rukovodeêim mjestima stekao je reputaciju cijenjenoga regionalnoga geologa, kako u domaêim, slovenskim i jugoslavenskim, tako i meunarodnim geoloπkim krugovima. u poëetku se je bavio istraæivanjima mineralnih sirovina, a ubrzo se ukljuëuje u tadaπnji i u, opêenito do sada, najveêi geoloπki projekt osnovnu geoloπku kartu 1:100.000, kroz kojega êe se afirmirati kao jedan od vodeêih slovenskih geologa. od 1962. do 1983. sudjelovao je u tim istraæivanjima prakgeologia croatica 55/1 103 -106 zagreb 2002 in memoriam dr. sc. pero mio» (19312001) pero mioë, a well-known slovenian geologist died on september 18, 2001. he was born in livno (bosnia and herzegovina) on november 19, 1931. he finished geological high school in panëevo (srbija) in 1951, and began his work with the geological institute in sarajevo (bosnia and herzegovina) as a geological technician. from 1955 while investigating the mineral deposits of bosnia and herzegovina he studied geology, graduating from the university of ljubljana (slovenia) in 1964. he completed his m.sc. and ph.d. studies at the university of zagreb (croatia) in 1976 and 1984, respectively. a major part of his 35 yr. professional and scientific career was spent in the geological institute of slovenia, from 1962 to his retirement in 1997. he participated in the regional geological investigation of slovenia, mostly during the work on the basic geological map at the scale 1:100.000, but also through tectonic and petroleum-geological investigations of the slovenian part of the eastern alps, karavanke mts. and the pannonian basin. from 1967 to 1972 he was leader of the regional geological and mineral deposit investigations in africa (algeria and guinea). from 1974 to 1994 he was a head of the department of regional geology of the geological institute of slovenia. even after his retirement he was still an active participant of regional projects in the area of the eastern alps and pannonian basin. for this purpose he undertook his last journey to sopron (hungary), to attend the pancardi meeting, but he suddenly died in wiener neustadt (austria). his death, which is a huge loss for slovenian geology, was also very sad news for geologists in neighbouring countries, especially croatia, where he was also treated as a croatian geologist. dr. pero mioë was a member of the editorial board of the journal “geologia croatica” for many years. by his death we have lost a very important and devoted associate, colleague and friend. 104 geologia croatica 55/1 tiëno na podruëju cijele slovenije: u krπkim dinaridima, posavskim borama, alpama, istoënim karavankama i u slovenskome dijelu panonskoga bazena. autor je ili suautor listova i tumaëa za osnovnu geoloπku kartu listova slovenj gradec, ravne na koroπkem, maribor in leibnitz, nagykanizsa i »akovec od 1974. punih 20 godina rukovodio je odjelom za regionalnu geologiju geoloπkoga zavoda πto mu je omoguêilo ëeste kontakte i suradnju s mnogobrojnim kolegama geolozima i izvan slovenije. kroz to vrijeme zastupao je svoj zavod i slovensku geologiju u odborima i komisijama pri saveznome geoloπkom zavodu u beogradu. u meuvremenu, osim radova za osnovnu geoloπku kartu, vodio je i regionalnogeoloπka istraæivanja, kartiranja i izradu tumaëa listova djebel filfila i aine kechera (1:50.000) u sjeveroistoënome alæiru (1967-1970). sudjelovao je u istraæivanjma æeljeznih ruda u nimbi, u afriëkoj guineji. paralelno uz opisana istraæivanja posvetio se i znanstvenome radu i napredovanju pa je upisao i uspjeπno zavrπo poslijediplomski studij na prirodoslovnomatematiëkome fakultetu sveuëiliπta u zagrebu obranom magistarskoga rada pod naslovom "geoloπka graa kobanskoga" 1976. god. na istome je fakultetu i doktorirao tezom "geologija prijelaznog podruëja izmeu juænih i istoënih alpa slovenije" 1984. god. u kojoj je saæeo dotadaπnje rezultate istraæivanja kojima se i najviπe bavio kao πto su regionalna tektonika i podpovrπinska geoloπka graa u vezi s naftnogeoloπkom problematikom. u tim je geoloπkim disciplinama nastavio raditi i nakon odlaska u mirovinu u podruëju slovenskoga dijela alpa, karavanka i panonskoga bazena u suradnji s kolegama iz svoje matiëne kuêe geoloπkoga zavoda u ljubljani i sa struënjacima i znanstvenicima iz susjednih zemalja austrije, maarske i hrvatske. pero mioë bio je omiljen i posebno cijenjen u hrvatskim geoloπkim krugovima. rado je suraivao sa svima bilo kao strukovni predstavnik svojega zavoda ili slovenije s odgovarajuêim institucijama u hrvatskoj ili na osobnoj struënoj i znanstvenoj razini s hrvatskim geolozima kroz razliëite projekte. na sveuëiliπtu u zagrebu je magistrirao i doktorirao, bio je dugogodiπnji ëlan (sve do smrti) znanstvenoga vijeêa za naftu hazu, a unutar njega ëlan izvrπnoga odbora sekcije za geologiju, geofiziku i geokemiju. u proteklih 30-ak godina redovito je sudjelovao na mnogim geoloπkim skupovima u hrvatskoj s regionalnogeoloπkom i naftnogeoloπkom problematikom. publicirao je u hrvatskim ëasopisima (bulletin scientifique, nafta, geologia croatica, vijesti hgd-a) i zbornicima skupova, a bio je i ëlan uredniπtva u naπem ëasopisu. sve je to dostatno da ga se moæe smatrati i hrvatskim geologom, posebice kada se zna i za njegovo izvorno hrvatsko domoljublje. smrt dr.sc. pere mioëa kod hrvatskih geologa, koji su ga poznavali i s njime suraivali, ostavlja ne samo tugu za prijateljem i kolegom veê i osjeêaj trajnoga gubitka odlaskom ovoga plemenitoga i dobroga ëovjeka. ivo veli∆ 105in memoriam: dr.sc. pero mioë popis objavljenih radova m i o », p. (1966): razvoj scaglie v severozahodnih dinaridih.i. kolokvij o zunanjih dinaridih, 28-29, ljubljana. m i o », p. (1968): sedimenti s pelagiëno mikrofavno v severozahodnih dinaridih.i. kolokvij o geologiji dinaridov, 97-100, ljubljana. mio», p. (1972): geoloπki razvoj magmatizma v vzhodnih karavankah.vii. kongres geol. sfrj, ii, 223-232, zagreb. mio», p. & ramov©, a. (1973): erster nachweis der unterdevons im kozjak-gebirge (possruch), westlich vom maribor (zentralalpen).bull. sci. yougoslav., sec. a, 18/7-9, zagreb. mio», p. (1974): osnovna geoloπka karta sfrj 1:100.000, list ravne.geologija, 17, 500-502, ljubljana. mio», p. (1975): osnovna geoloπka karta sfrj 1:100.000, list ravne.geologija, 18, 363-365, ljubljana. mio», p. (1975): prilog poznavanju tektonskih odnosa graniëne zone istoënih posavskih bora i dinarskog πelfa.zbornik ii. skupa znan. sav. za naftu jazu, 223-228, zagreb. mio», p. & ©ribar, l. (1975): jurski skladi v severnih karavankah.geologija, 18, 87-97, ljubljana. mio», p. (1977): geoloπka zgradba dravske doline med dravogradom in selnico.geologija, 20, 193-230, ljubljana. mio», p. (1978): tolmaë za list slovenj gradec l 33-55.zvezni geoloπki zavod beograd, 74 p. mio», p. & ænidar»i», m. (1978): osnovna geoloπka karta sfrj 1:100.000, list slovenj gradec.zvezni geoloπki zavod, beograd. mio», p. (1981): tektonski odnosi savske navlake prema susjednim jedinicama u sloveniji te njena veza sa πirim jugoslavenskim podruëjima.nafta, 32, 543-548, zagreb. mio», p. & ænidar»i», m. (1982): komparacija metamorfnih stijena slovenije sa πirim jugoslavenskim podruëjem.x. jubilarni kongres geol. jugoslavije, zbornik radova, 1, 341-350, budva. brezigar, a., mio», p., rijavec, j. & ogorelec, b. (1983): geoloπka zgradba predpliocenske podlage velenjske udorine in okolice.geoloπki zbornik, 3, 17-20, ljubljana. mio», p. (1983): osnovna geoloπka karta sfrj 1:100.000. tolmaë za list ravne na koroπkem l 33-54.zvezni geoloπki zavod, beograd, 69 p. mio», p. & ænidar»i», m. (1983): osnovna geoloπka karta sfrj 1:100.000. list ravne na koroπkem.zvezni geoloπki zavod beograd. mio», p. (1984): geologija prehodnega obmoëja med juænimi in vzhodnimi alpami v sloveniji.doktorska disertacija, sveuëiliπte u zagrebu, 214 p. mio», p. (1986): tektonska gradja terena uzduæ periadrijatskog πava u sloveniji.xi. kongres geol. jugoslavije, 3, 507-520, tara. mio», p., ani»i∆, b. & ænidar»i», m. (1986): sedimentation of the smrekovec sedimentary-volcanic series in the northern slovenia (nw yugoslavia).v. skup sedimentologa jugoslavije, 61-64, brioni. mio», p. & ænidar»i», m. (1987): potencialna nahajaliπëa arhitektonsko-gradbenega kamna v slovenskih vzhodnih alpah.geol. zbor., 7, 10-11, ljubljana. brezigar, a., ogorelec, b., rijavec, l. & mio», p. (1988): geoloπka zgradba predpliocenske podlage velenjske udorine in okolice.geologija, 30, 31-65, ljubljana. mio», p. & ænidar»i», m. (1988): osnovna geoloπka karta sfrj 1:100.000. tolmaë za list maribor in leibnitz.zvezni geoloπki zavod, beograd, 60 p. ænidar»i», m. & mio», p. (1988): osnovna geoloπka karta sfrj 1:100.000. list maribor in leibnitz.zvezni geoloπki zavod, beograd. mio», p. & ænidar»i», m. (1989): osnovna geoloπka karta sfrj 1:100.000. tolmaë za list nadjkanjiza.zvezni geoloπki zavod, beograd, 60 p. ænidar»i», m. & mio», p. (1989): osnovna geoloπka karta sfrj 1:100.000. list nadjkanjiza.zvezni geoloπki zavod, beograd. mio», p. & ænidar»i», m. (1991): paleogeographic evolution of the area between eastern alps and dinaric carbonate platform from triassic up to tertiary in slovenia (nw yugoslavia).the second international symposium on the adriatic carbonate platform, abstracts, 64, zadar. mio», p. (1992): pregled obstojeëih geoloπkih kart v sloveniji ter primerjava s stanjem v drugih razvitih dræavah.strateπka konferenca, raziskovalno polje geologija in rudarstvo, 19-24, ministarstvo za znanost in tehnologijo, ljubljana. mio», p. & ænidar»i», m. (1992): nafta in plin.zbornik onesnaæevavanje i varstvo okolja: geologija in tehnika za okolje, 45-48, zavod za tehniëno izobraæevanje ljubljana. mio», p. & ænidar»i», m. (1993): geoloπke razmere na obmoëju jugozahodnega podaljπka radgonske depresije.rud.-metal. zb., 40/1-2, 12, ljubljana. mio», p., ani»i», b. & ænidar»i», m. (1993): pre-tertiary basement characteristics of the western border of pannonian basin slovenia.in: erdélyi, v.g. & vetö, i. (eds.): abstracts. hungarian geological society, 42, budapest. sachsenhofer, r.f., jelen, b., mio», p., skaberne, d. & ænidar»i», m. (1994): coalification of tertiary sediments in eastern slovenia.in: alcapa 2: geological evolution of the alps-carpathain-pannonian system: voinesti-covasna, romania, october 21-22, abstracts (romanian journal of tectonics and regional geology, 75, sup. 1) , 54-55, institutul geologic al romaniei bucuresti. mio», p. (1995): dacitni vulkanizem zahodnega pohorja.geol. zb., 10, 42-44, ljubljana. mio», p. (1995): pregled tektonske grae podruëja izmeu periadriatskog lineamenta i jadransko-dinarske karbonatne platforme u sloveniji.in: vlahovi∆, i., veli∆, i. & ©parica, m. (eds.): 1. hrvatski geoloπki kongres, opatija, knjiga saæetaka, 64, institut za geoloπka istraæivanja, zagreb. 106 geologia croatica 55/1 mio», p. (1995): pregled tektonike podruëja izmeu periadriatskog lineamenta i jadransko-dinarske karbonatne platforme u sloveniji.in: vlahovi∆, i., veli∆, i. & ©parica, m. (eds.): 1. hrvatski geoloπki kongres, opatija, zbornik radova, 2, 387-391, institut za geoloπka istraæivanja, zagreb. mio», p. & ænidar»i», m. (1996): oil geology investigations and favourability for oil fields of the slovenian part of the pannonian basin.in: safti∆, b. (ed.). economic aspects of petroleum exploration: an approach to rational exploration. working materials, 66-69, ina-naftaplin, zagreb. mio», p. & ænidar»i», m. (1996): geological characteristics of the oil fields in the slovenian part of the pannonian basin.geologia croatica, 49/2, 271-275, zagreb. mio», p. & ænidar»i», m. (1997): pregled tektonske zgradbe vzhodnih karavank.13. posvetovanje slovenskih geologov. povzetki referatov, geoloπki zbornik, 11, 20-21, ljubljana. mio», p. (1997): v spomin dr. borisu bercetu.geologija, 40, 7-9, ljubljana. mio», p. (1997): tectonic structures along the periadriatic lineament.geologia croatica, 50/2, 251-260, zagreb. mio», p. (1998): sploπni pregled geoloπke zgradbe pohorja.in: g r a d i π n i k, s. (ed.): kamnine pohorja, 4. stalna zbirka v gradu slovenska bistrica. zavod za kulturo slovenska bistrica, 4-7, slovenska bistrica. mio», p. & markovi∆, s. (1998): osnovna geoloπka karta republike slovenije in republike hrvaπke. list l 3357, »akovec.geodetski zavod slovenije, ljubljana. mio», p. & markovi∆, s. (1998): osnovna geoloπka karta slovenije in hrvaπke 1:100.000. tolmaë za list »akovec l33-57.inπtitut za geologijo, geotehniko in geofiziko, ljubljana. institut za geoloπka istraæivanja, 84 p., zagreb. haas, j., mio», p., pami∆, j., tomljenovi∆, b., árkai, p., bérczi-makk, a., koroknai, b., kovács, s. & felgenhauer, e.r. (2000): complex structural pattern of the alpine-dinaric-pannonian triple junction.int. j. earth sci., 89, 377-389, berlin. mio», p. & pami∆, j. (2000): the internal dinaric units in the adjoining area of the alps and dinarides in slovenia.pancardi 2000, dubrovnik, croatia, abstracts (vijesti hrvatskoga geoloπkog druπtva, 37/3), 143-144, hrvatsko geoloπko druπtvo, zagreb. mio», p. & ænidar»i», m. (2001): pregled geoloπke zgradbe obrobja panonskega bazena v sloveniji.15. posvetovanje slovenskih geologov: povzetki referatov. geoloπki zbornik, 16, 64-65, ljubljana. mio», p. (2001): overview of neotectonic structure of southwest margin of pannonian basin in slovenia.pancardi 2001, sopron, hungary. mio», p. (2001): karakteristike dinarske karbonatne platforme u sloveniji.1. znanstveni skup karbonatna platforma ili karbonatne platforme dinarida. in: d r a g i » e v i ∆, i. & veli∆, i. (eds.): knjiga saæetaka, 57-59, zagreb. 287 hughes.indd agriopleura morphotypes of the lower aptian shu’aiba formation of saudi arabia geraint wyn ap gwilym hughes 1. introduction the shu’aiba formation consists of carbonates that are extensively present in the arabian subsurface where they provide a significant hydrocarbon reservoir, in the shaybah field of southern saudi arabia. the carbonates were deposited in a variety of environments (fig. 1; hughes, 1998, 1999, 2000, 2001) on an extensive shallow marine platform that occupied much of the arabian platform in which a number of intra-shelf basins were present. the basin flanks provided suitable conditions for rudist colonization and development of rudist bank complexes during the early to possibly late aptian (witt & gökdag, 1994). a variety of rudists are present of which, within the uppermost part especially of the shu’aiba formation, species of the elevator rudist agriopleura display two distinctive morphologies (fig. 2). their vertical succession provides a refined depositional layering scheme of possible application for an improved reservoir layer model. a need to understand the depositional environment and cyclicity is important for the optimal exploitation of the hydrocarbon reserves of the field. the inability of existing seismic data to resolve intra-reservoir facies variations justifies the ongoing detailed micropalaeontological and macropalaeontological analysis to which this paper is a contribution. 2. previous work the shu’aiba formation has been studied extensively in oman and the emirates (pittet et al., 2002; van buchem et al., 2002; masse et al., 1998), but mainly for sedimentological and sequence stratigraphic aspects. studies in saudi arabia have been limited to relatively recent investigations of the shaybah field but have involved an integration of semi-quantitative micropalaeontological analysis of closely-spaced core samples with macropalaeontology (hughes, 1998, 2000, 2001, 2002). a variety of rudists have been identified from the shu’aiba formation in saudi arabia (skelton et al., 1998; hughes, 2000; skelton & masse, 2000), and have led to the development of a three dimensional depositional model (aktas et geologia croatica 56/2 133–138 3 figs. zagreb 2003 key words: agriopleura, palaeoenvironment, lower aptian, rudist morphotypes, shu’aiba, saudi arabia, foraminifera. saudi aramco, geological technical support division, box 10646, dhahran 31311, saudi arabia; e-mail: geraint.hughes@aramco.com.sa abstract the shu’aiba formation of the arabian platform consists of aptian carbonates in which rudists are important biocomponents. it is an important hydrocarbon reservoir. semi quantitative micropalaeontology and macropalaeontological observations from cores have enabled three-dimensional interpretation of biofacies and lithofacies that have guided optimal reservoir exploitation. in addition to the presence of offneria murgensis masse, o. cf. nicolinae (mainelli), glossomyophorus costatus masse et al., oedomyophorus shaybahensis skelton, and horiopleura cf. distefanoi boehm the shu’aiba formation contains agriopleura cf. blumenbachi (studer) and a. cf. marticensis (d’orbigny). although species of agriopleura are locally present over short sections below the glossomyophorus costatus accumulations of the middle part of the formation, they are very well represented in its upper part, where they are typically associated with the moderately deep marine benthonic foraminifera praechrysalidina infracretacea, vercorsella arenata, debarina hahounerensis and palorbitolina lenticularis. agriopleura cf. blumenbachi and a. cf. marticensis display contrasting morphologies. agriopleura cf. marticensis is cone-shaped, with a fixed valve expansion angle of 30–35º, and with average right valve dimensions of 3.5 cm length and 2.5 cm maximum diameter. a recently observed “clinger” form is, however, 70 cm long. a. cf. blumenbachi is elongate, almost tube-like, with a very low rate of fixed valve diameter increase, of less than 10º with average right valve dimensions of 6.5 cm length and 2.2 cm maximum diameter. the two forms are present in distinct biofacies. both agriopleura facies are considered to compose a single depositional cycle, and it is possible that the elongate shape of agriopleura cf. blumenbachi is better adapted to the slightly higher rate of sedimentation associated with the relatively rapid sea level rise at the base of each new depositional cycle. the cone-shape of a. cf. marticensis is possibly adapted to lower rates of sedimentation during the relatively slower rate of sea level rise, and ultimate fall of the upper part of each depositional cycle. 134 geologia croatica 56/2 135hughes: agriopleura morphotypes of the lower aptian shu’aiba formation... al., 1999) that had guided recent development of the shaybah field. 3. rudists of the shu’aiba formation with the assistance of dr. peter skelton, seven rudist species have been identified in the shu’aiba formation of saudi arabia (skelton & masse, 2000; hughes, 2000). they are represented by agriopleura cf. blumenbachi (studer), a. cf. marticensis (d’orbigny), glossomyophorus costatus masse et al., oedomyophorus shaybahensis skelton, offneria cf. nicolinae (mainelli), o. murgensis masse and horiopleura cf. distefanoi boehm. the preferred palaeoenvironment of each species has been deduced from stacking arrangements and the palaeoenvironmental information provided by the associated biocomponents (fig. 2). within the informal three-layered model of the formation (hughes, 2000), rudists are absent from the basal, lowermost and regionally extensive layer representing a deep open marine, orbitolinid and planktonic foraminiferal-bearing carbonate platform. the overlying, compound, highly differentiated layer represents rudist bank complex, lagoon and fore-bank environments. the upper layer is characterized by deposits indicating predominantly moderately deep, open platform conditions with extensive areas with common agriopleura rudists and sparsely distibuted shallow rudist banks. agriopleura species two morphotypes of agriopleura have been recognized, by dr. peter skelton, from the shu’aiba formation of saudi arabia – agriopleura cf. marticensis and agriopleura cf. blumenbachi – and they are easily distinguished by their clearly different morphology. both, however, display the typical elevator growth orientation. agriopleura cf. blumenbachi (fig. 2) is typically thin, elongate and cylindrical resulting from a low expansion rate of the fixed, or right, valve with an apical angle less than 10º. the right valve typically has a very low degree of curvature, which when present is mostly the result of geniculate growth following disturbance and slight tilting during early growth history. it displays a maximum length of 6.5 cm and 2.2 cm diameter. the outer margin of the right valve is typically smooth, but some specimens display small extensions to the growth lamellae, most of which are irregular in length. this species has only been found in an elevator position, unlike a. cf. marticensis, as described below. it has only been found within the upper layer of the shu’aiba formation at shaybah. it is typically found in association with the foraminiferal species praechrysalidina infracretacea luperto sinni, debarina hahounerensis fourcade, raolt & vila, vercorsella arenata arnaud-vanneau, bolivina sp., rotalia sp. and palorbitolina lenticularis (blumenbach) together with lithocodium aggregatum elliott (fig. 2). rare specimens of the planktonic foraminiferal species hedbergella delrioensis (carsey) are also present within this association. agriopleura cf. marticensis is cone-shaped (figs. 2 and 3) and displays a relatively high rate of expansion of the fixed valve and an apical angle of between 30–35º. it displays a maximum length of 3.5 cm length and 2.5 cm diameter. the outer margin of the right valve displays characteristic extensions to the growth lamellae, most of which are rather irregular in the degree of their extension. these extensions typically radiate out from the right valve and suggest a possible stabilizing function within poorly consolidated sediments. one recently discovered specimen, however, displays a horizontal, clinger growth habit, as the lateral growth lamellae are only developed on the lowermost side where it was in contact with the sediment (fig. 3a). it is well represented in the upper layer of the shu’aiba formation, in addition to forming the basal unit of the glossomyophorus costatus–offneria murgensis associations in the middle layer. it is typically found in association with the foraminiferal species palorbitolina lenticularis (blumenbach), and simple quinqueloculina and biserial agglutinated species, and with the dasyclad algae salpingoporella fig. 1 depositional regimes of the shaybah field, saudi arabia. 134 geologia croatica 56/2 135hughes: agriopleura morphotypes of the lower aptian shu’aiba formation... fig. 2 agriopleura species and their microfossil association. 1 – dasyclad alga; 2 – coptocampylodon lineolatus; 3 – salpingoporella dinarica; 4 – quinqueloculina sp.; 5 – biserial agglutinated foraminifera; 6 – large echinoid spine; 7 – palorbitolina lenticularis; 8 – lithocodium aggregatum; 9 – praechrysalidina infracretacea; 10 – debarina hahounerensis; 11 – indeterminate rotaliid; 12 – textulariid; 13 – bolivina sp.; 14 – vercorsella arenata. 1 2 3 4 5 6 7 8 9 10 11 8 12 13 14 7 ag rio pl eu ra c f. m ar tic en si s ag rio pl eu ra c f. bl um en ba ch i r el at iv el y sh al lo w er bi of ac ie s 136 geologia croatica 56/2 137hughes: agriopleura morphotypes of the lower aptian shu’aiba formation... dinarica radoičić and coptocampylodon lineolatus elliott (fig. 3). palaeoenvironmental and stratigraphic interpretation in the upper shu’aiba, both agriopleura species are present within wackestones and packstones, but form almost individually exclusive populations. agriopleura cf. blumenbachi is most commonly present, and is often without the presence of a. marticensis. these associations are always developed with agriopleura cf. blumenbachi forming the lower unit up to 97 cm thick, overlain by beds up to 83 cm thick containing a. marticensis and both typically display elevator growth habits confirming their position within an environment of net sedimentation. the foraminiferal associations present with both species indicate normal salinity conditions. the association of complex walled agglutinated foraminiferal species and rare planktonic foraminifera with a. cf. blumenbachi suggests that this species occupied moderately deep marine conditions with open marine influence (fig. 2). the shallower foraminiferal associations found with a. cf. marticensis suggest relatively shallower conditions, and that both species may respectively represent the lower, deeper and upper, shallower part of a depositional cycle. in general, the tendency of a. cf. blumenbachi to display near vertical orientation in the studied cores would suggest limited disturbance by wave action. this enables a depth range of below fair-weather wave base to be estimated, to the shallowest planktonic foraminiferal depth. banner & simmons (1994) suggest 150 feet as the shallowest planktonic foraminiferal range, but this is considered to be too deep for the shu’aiba platform. although individual beds may reach 4.5 m in thickness, the palaeobathymetry represented by this single cycle would be in excess of this, but the generally disturbed orientation of a. cf. marticensis suggests that the upper and shallowest part of the depositional cycle was probably above fair weather wave base. one large specimen of a. cf. marticensis has been found displaying a clinger life habitat (fig. 3a), with preferential development of lateral growth lamellae on the ventral side in a presumed adaptation for additional stability. unlike the predominant elevator lifestyle of the specimens encountered, where conditions of net sedimentation prevailed, the clinger specimen testifies to an adaptation to shallower, higher energy conditions in an area of sediment bypass. controls on agriopleura morphology in view of the overall morphological similarity of the two species of agriopleura, and the lack of statistical data to demonstrate that intermediate forms exist, it is possible that both forms represent two distinct species, here compared with agriopleura marticensis (d’orbigny, 1850) and agriopleura blumenbachi (studer, 1834). this interpretation does not conform to the interpretation of such similar morphology contrasts of praeradiolites species described by floquet (1998), and further biometrics are recommended before a convincing decision is achieved for the two morphological variants here assigned to species of agriopleura. regardless of the taxonomic arguments, there must be some environmental control on the adaptive nature of the conical right valve shape of a. cf. marticensis over the slender, cylindrical right valve of a. cf. blumenbachi. it is possible that the elongate cylindrical shape of a. cf. blumenbachi is an adaptation to the relatively high rate of ambient sediment accumulation during the lower part of the depositional cycle, when the ability to maintain the commissure above the sediment would be vital for survival. the conical form of a. cf. marticensis may preferentially be adapted to lower rates of sediment accumulation during the upper part of a depositional cycle, when the need for increased stability in a relatively higher energy regime was achieved by greater width and lamellar extensions were critical adaptations. the adaptation of a clinger lifestyle, with the associated preferential development of accentuated ventral growth lamellae further testifies to the morphological plasticity of agriopleura. agriopleura cf. marticensis agriopleura cf. blumenbachi 1 cm 1 cm fig. 3 (a) agriopleura cf. marticensis in a horizontal position and preferential growth line extensions on the lowermost side. this is interpreted as a possible “clinger” life habitat of this particular specimen. (b) agriopleura cf. blumenbachi also in a horizontal position, but here possibly the result of displacement from an elevator growth habit, based on the relatively similar growth lamellae on the lower and upper sides, together with an unusual, partial, irregular geopetal sediment infill. 136 geologia croatica 56/2 137hughes: agriopleura morphotypes of the lower aptian shu’aiba formation... 4. conclusions in the uppermost depositional layer of the lower aptian carbonates of the shu’aiba formation in shaybah field, saudi arabia, the elevator rudist genus agriopleura displays a common and regionally extensive distribution. two morphotypes are distinguished, of which the slender cylindrical form is assigned to a. cf. blumenbachi and the squat, conical form to a. cf. marticensis. a. cf. blumenbachi is typically present within the lower part of a depositional cycle, or parasequence, and associated with relatively deep marine foraminifera, including rare planktonics. shallower, lower diversity foraminiferal assemblages are found within the upper part of the depositional cycle where a. cf. marticensis is well represented. there is no overlap in the distribution of both morphotypes, and they are tentatively assigned to the two species of agriopleura. in both cases, the energy levels are considered to have been relatively low, but sufficiently high to introduce sediment for support of the elevator life-style. of note is the single observation of a. cf. marticensis adapting to a clinger mode of life, and is considered to represent localized higher energy conditions in areas of net sediment bypass. the distribution of the morphotypes are concluded to have been controlled by palaeobathymetric variations linked to the transgressive “catch-up” and regressive “keep-up” parts of a single depositional cycle. these cycles, up to 4.5 m thick, are repeated through this upper layer of the shu’aiba formation. during hydrocarbon exploitation of the uppermost part of the shu’aiba reservoir at shaybah field, the contribution of both agriopleura species lies in providing a fine-scaled stratigraphy and units of inter-well correlation that lead to an improved model for reservoir characterisation. 5. references aktas, g., hughes, g.w., abu-bshait, a.j. & algarni, s. (1999): stratigraphic framework of shu’aiba formation, shaybah field, saudi arabia: a basis for reservoir development of an aptian carbonate ramp complex.– 4th middle east geoscience congress, geo 2000, abstracts, geoarabia, 5, 11. banner, f.t. & simmons, m.d. (1994): calcareous algae as water-depth indicators: an example from the early cretaceous carbonates of northeast arabia.– in: simmons, m.d. (ed.): micropalaeontology and hydrocarbon exploration in the middle east. chapman and hall, london, 243–252. floquet, m. (1998): praeradiolites ciryi, a polymorphic rudist from upper santonian and campanian carbonate formations of the castilian ramp (northern spain).– in: masse, j.-p. & skelton, p.w. (eds.): quatrieme congres international sur les rudistes, geobios, mem. spec., 22, 111–123. hughes, g.w. (1998): middle east aptian rudist–foraminiferal–algal associations and their possible modern arabian gulf analogue.– in: masse, j.-p. & skelton, p.w. (eds.): quatrieme congres international sur les rudistes, geobios, memoir special, 22, 147–158. hughes, g.w. (1999): bioecostratigraphy of the shu’aiba formation of saudi arabia.– in: höfling, r. & steuber, t. (eds.): fifth international congress on rudists, abstracts and field trip guides. erlanger geologische abhandlungen, sonderband 3, erlangen, 25–27. hughes, g.w. (2000): bioecostratigraphy of the shu’aiba formation, shaybah field, saudi arabia.– geoarabia, 5, 545–578. hughes, g.w. (2001): palaeoenvironments of lower aptian agglutinated foraminifera of saudi arabia.– in: holcova, k. & bubik, m. (eds.): sixth international workshop on agglutinated foraminifera, abstracts. prague, czech republic, september 1–7, 2001, czech geological survey, prague, 25–26. hughes, g.w. (2002): the stratigraphic significance of microbiofacies to selected saudi arabian reservoirs.– geoarabia, 7, 248–290. masse, j.-p., chartrousse, a. & borgomano, j. (1998): the lower cretaceous (upper barremian–lower aptian) caprinid rudists from northern oman.– in: masse, j.-p. & skelton, p.w. (eds.): quatrieme congres international sur les rudistes. geobios, mem. spec., 22, 211–223. pittet, b., van buchem, f.s.p., hillgartner, h., razin, p., grotsch, j. & droste, h. (2002): ecological succession, palaeoenvironmental change, and depositional sequences of barremian–aptian shallowwater carbonates in northern oman.– sedimentology, 49, 555–581. skelton, p.w. & masse, j.-p. (2000): synoptic guide to the lower cretaceous rudist bivalves of arabia.– soc. econ. paleont. miner., spec. publ., 69, 85–95. skelton, p.w., hughes, g.w. & aktas, g. (1998): rudists of the shu’aiba formation in the shaybah field, 138 geologia croatica 56/2 eastern saudi arabia.– in: höfling, r. & steuber, t. (eds.): fifth international congress on rudists, abstracts and field trip guides. erlanger geologische abhandlungen, sonderband 3, erlangen, 65–66. van buchem, f.s., pittet, b., hillgarten, h., grotsch, j., al-mansouri, a., billing, i.m., droste, h.o. & steenwinkel, m. (2002): highresolution sequence stratigraphic architecture of the barremian–aptian carbonate systems in northern oman and the united arab emirates kharaib and shu‘aiba formations.– geoarabia, 7, 461–500. witt, w. & gökdag, h. (1994): orbitolinid biostratigraphy of the shu’aiba formation (aptian), oman – implications for reservoir development.– in: simmons, m.d. (ed.): micropalaeontology and hydrocarbon exploration in the middle east. british micropalaeontological society publications series. chapman and hall, london, 440 p. manuscript received december 12, 2002. revised manuscript accepted november 04, 2003. gc-60-2.indb 1. introduction from the early 1960’s to the late 80’s, extensive exploration for uranium ore took place in the former yugoslavia, including croatia (braun, 1984). prospecting activities by the croatian geological survey identified several locations in the slavonian mts. (croatia) with an increased level of radioactivity (braun et al., 1983), particularly in the area of mts. psunj and papuk. the carbon age of the metasediments of radlovac creek – known as the radlovac series – has been determined from the fossil flora (brkić et al., 1974). the position of this series, which includes rocks with higher background radioactivity, is shown in fig. 1. the tectonic setting and structural fabric of these and associated rocks have been described by jamičić (1976, 1979). the radlovac series is a metaschist formation, and an increased level of radioactivity has been identified in uranium minerals in the radlovac series metasediments at mt. papuk, croatia stjepan šćavničar1, vladimir bermanec1, goran kniewald2, delko barišić2 and višnja oreščanin2 several, apparently unrelated locations. this is also true for deeper strata (samples from the prospecting boreholes). a detailed synthesis of this research was given by jurković (2003). in 1984 the institute of mineralogy and petrology of the faculty of sciences in zagreb attempted x-ray diffraction analysis of the uranium-bearing minerals in the radlovac metaschists. due to the complex mineralogical structure of the rocks, the separation methods available at that time (magnetic separation, granulometry, high-density liquids) did not yield satisfactory results, and the minerals responsible for the increased radioactivity were not unambiguously identified, even though both the light and heavy mineral fractions as well as composite rock samples were analyzed. however, it was inferred that the activity was due to the presence of uranyl arsenates of calcium, copper, iron or barium (šćavničar, 19843). therefore, the aim of the present study is to determine the uranium-bearing minerals of those samples, using contemporary and stateof-the-art xrd, edxrf, sem with edx spectrometer and gamma spectrometric methods. 2. materials and methods some of the original samples, which were analysed in 1984, were still available to the authors. these samples (which show the strongest background activities) were taken from low-grade metamorphosed sedimentary rocks of the radlovac series in mt. papuk, which crops out near the ninkovac creek. the host rock has a schistlike structure and contains muscovite, quartz, pyrophyllite, chlorite, albite, microcline, chloritoid, and, occasionally, calcite and dolomite. this mineral assemblage indicates a sequence of low-grade metamorphism. uranium, originating from the surrounding weathering zones, was deposited in the form of u-oxysalts in these rocks. the radioactivity of the analyzed samples was determined by gamma spectrometry. prior to gamma geologia croatica 60/2 165–171 6 figs. 2 tabs. zagreb 2007 key words: uranium mineralization, meta-torbernite, meta-uranospinite, meta-zeunerite, mt. papuk, radlovac series, epigenetic–sedimentary mineralisation. 1 university of zagreb, faculty of science, institute of mineralogy and petrology, horvatovac bb, hr-10000 zagreb, croatia; e-mail: vberman@public.carnet.hr 2 rudjer bošković institute, department of marine and environmental research, pob 180, hr-10002 zagreb, croatia abstract applying a combination of different methods – x-ray diffraction, scanning electron microscopy, gamma-spectroscopy and x-ray spectroscopy, a suite of uranium minerals, meta-torbernite, meta-uranospinite and meta-zeunerite was identified in metasediments of the radlovac series at the mt. papuk area, croatia. the accessory minerals galena, zircon, rutile, chalcopyrite and cuprite, as well as an unidentified ni-bearing phase are also present. the mineral assemblage indicates a sequence of epigenetic and supergene processes affecting the radlovac series. 3 šćavničar, s. (1984): rentgenografska analiza mineralnog sastava radioaktivnih uzoraka stijena iz slavonije.– unpubl. report, archive of the croatian geological survey. 166 geologia croatica 60/2 spectrometry measurements, samples were placed into counting vessels of known geometry, sealed and stored for at least 4 weeks to allow ingrowth of gaseous 222rn (half-life of 3.8 days) and its short-lived decay products to equilibrate with the long-lived 226ra precursor in the sample. at the end of the ingrowth period, samples were counted on an inspector gamma spectrometer (‘canberra’ portable hpge detector coupled with a 8192 channel analyser). the system was calibrated using standard reference materials supplied by the international atomic energy agency (stream sediments iaea–306, iaea–313 and iaea–314). counting time was 80,000 seconds and recorded spectra were analyzed using the canberra genie 2k software. the activities of 40k were calculated from the 1460.75 kev-peak. activities of 226ra were calculated from the 609.4 kev peak of its 214bi progeny as well as 228ra activities from 911.1 kev-peak of its 228ac progeny. activities of 235u were calculated from 186 kev peak (after subtraction of the overlapping 226ra peak, which was calculated previously from 214bi). activities of 238u were calculated from the 235u activities assuming the 235u/238u activity ratio of 0.0460. this procedure was detailed by barišić (1989). 40k activity of 309.3 bq/kg corresponds to 1% of total potassium, 238u activity of 12.44 bq/kg corresponds to 1 ppm of uranium, while the 232th activity of 4.06 bq/kg corresponds to 1 ppm of thorium (barišić, 1996). samples with the highest activities were used for xrd investigations. the diffraction patterns of all samples were collected on a philips ‘xpert diffractometer using cukα radiation. powder diffraction data were collected in the range of 4–63° 2θ, and a step size of 0.02°. the obtained d-spacings and relative intensities of the patterns obtained were compared with reference values (jcpds 01–077–0124, 01–086–1787, 00–018– 0309). the diffractograms were analyzed using the philips proprietary computer code enabling a precise pattern analysis and the identification of very weak diffraction peaks. for elemental analysis, each sample was disaggregated in an agate mortar, pressed into pellets and measured by energy dispersive x-ray fluorescence method (edxrf; oreščanin et al., 2006, 2007). samples were irradiated by x-rays generated from a 109cd annular source. the incident angle was 50°. detection of the characteristic x-ray radiation from the sample was done with a liquid-n colled si(li) detector (canberra) with the following characteristics: detector size=30 mm2, si thickness=3 mm. be window=25 µm, fwhm for 5.9 kev 55fe 165 ev, the emerging angle was 74°, and the distance was 1.5 cm. spectra were collected by genie – 2000 software (canberra, meriden, ct, usa). collecting time was 10,000 s. spectral data were analyzed by canberra’s winaxil software. elemental concentrations in the thick targets were calculated using the ‘fundamental parameters’ method from the winfund package, with iaea srm sl–1 and soil 7 as the standards. the concentration (wi) of each element (i) was calculated according to the following formula: wi = nij / (kij dij fpij aij,m hij,m i i0 t), where nij is the net peak area of the characteristic xray line j; kij – calibration constant calculated on the basis of the standard reference material; dij – detector efficiency at eij energy; fpij – number of fundamental parameters; aij,m – attenuation of the x-rays due to matrix (m); hij,m – enhancement of the x-rays due to the matrix (m); i – intensity distribution of the characteristic lines and of the continuum in the excitation; i0 – factor taking into account the overall intensity of the source (the activity of the radio isotope); t – measurement time. scanning electron microscopy (sem) of the samples was done using a tescan se microscope vega ts5136 equipped with oxford detectors for secondary and back-scattered electrons. the operating voltage of the sem was 20 kv, the current was 20 na. the microscope is capable of elemental microanalysis through an eds detector and the inca 250 software package. fig. 1 location map of the radlovac series in the mt. papuk area. 167 3. results and discussion 3.1. x-ray diffraction x-ray diffraction analysis was run on available samples and the presence of minerals belonging to the metaautunite group was verified. as it was impossible to obtain pure mineral phases, there were numerous overlaps of diffraction peaks of the uranium minerals and other mineral phases such as quartz, micas and feldspars. however, the meta-autunite mineral group could be unambiguously identified based on their strongest lines. the unit cell could not be calculated from this data set, which – even if available – would not provide information on the mineral species due to the complex crystallochemical characteristics of the group. as in the earlier investigation (šćavničar, 19843), the samples investigated here contained muscovite, quartz, pyrophyllite, chlorite, albite, microcline, chloritoide, and occasionally dolomite and calcite. these minerals account for all diffraction peaks identified in the xrd patterns, except for one line of variable intensity around 8.8 ǻ. this peak belongs to the most intensive line in the powder xrd pattern of the meta-autunite mineral group. this line was also identified in most of the samples analyzed previously, but its intensity varies from barely discernible to conspicuous. the powder pattern of the chloritoid minerals presents a major difficulty in the identification process of uranium minerals present in the samples. some chloritoid group minerals have a strong diffraction line (of 10–20% intensity) at 8.9 ǻ, and its resolution from the line at 8.8 ǻ, belonging to the meta-autunite minerals, is difficult, if at all possible. chemical analysis would probably have provided the requisite information for mineral identification, but such an analysis was not feasible due to the substantial intergrowth of the various mineral phases present in the samples. 3.2. scanning electron microscopy investigation for the sem analysis of the radlovac series rocks, the samples were only sputtered with carbon and scanned for surface roughness (i.e. the surface topography of the sample). the different mineral phases were identified based on the atomic numbers of the elements in the mineral crystal structures. in this way, the heavy elements could be identified very easily. in the samples collected for the previous investigation, sem scanning revealed the presence of numerous aggregated fragments of uranium minerals. the fragments are hypidiomorphic to idiomorphic with a platy appearance. the plates grow in a subparallel arrangement and a tetragonal symmetry is clearly visible in octagonal sections. the plates have nearly perfect cleavage parallel to the base (fig. 2a and b). the crystals are 2–20 μm in length, their aggregations up to 0.5 cm in size. smaller crystals have rectangular (fig. 3a), the larger ones octogonal sections, which can be diagonally elongated (fig. 3b). several, rounded fragments of zircon were identified in sample zmago–1–4–3a. 3.3. energy dispersive x-ray analysis the energy dispersive x-ray analysis (edx) showed that the principal elements in the uranium mineral structures are u, as and cu in one group of samples, and u, p, cu and ca in the other group. minor amounts of fe, ba and si were identified in the uranium minerals. supported by xrd investigations, it can be concluded that fig. 2 a) polished sample ra–4 with visible uranium mineralization (white grains are uranium minerals, grey grains are baryte crystals); b) a more detailed view of fig. 2a showing meta-zeunerite platelets growing next to baryte. a b šćavničar et al.: uranium minerals in the radlovac series metasediments... 168 geologia croatica 60/2 several uranium minerals are present in the samples – meta-torbernite [cu(uo2)2(po4)2]·8h2o, meta-uranospinite [ca(uo2)2(aso4)2]·8h2o, and meta-zeunerite [cu(uo2)2(aso4)2]·8h2o. the edx spectra show that the meta-torbernite is a single phase, while there seems to a solid solution series between meta-uranospinite and meta-zeunerite resulting in possible variations in the composition of discrete crystal fragments. the aggregates of these uranium minerals are partly interspersed with the other rock-forming minerals, resulting in a poikiloblastic texture (porphyroblasts which are riddled with finer grained inclusions of other minerals) of the uranium minerals. small inclusions of baryte within the uranium minerals are common (fig. 4a). the baryte fragments have typical morphologies with rhombic sections. they are 2–20 µm in size and formed by several subparallel plates. individual baryte crystals associated with other minerals are also represented (fig. 5), but their incorporation into the uranium minerals is more common (fig. 4a). small amounts of silica have been identified in the baryte. in some samples (i.e. sample zmago–c) a copper oxide phase (most probably cuprite) was observed. it occurs in the form of needle-like crystals up to 200 µm in length, and below 1 µm in thickness (figs. 6a and b). the primary form of uranium mineralization has not been identified, but the presence of chalcopyrite was established. this chalcopyrite could have been the primary source of copper for the deposition of cuprite, but also provided copper for meta-torbernite and metazeunerite. a fragment of galena, ca. 15 µm in size was observed next to cuprite in one of the samples. a nickel-containing mineral phase was also identified. fig. 3 a) small crystals of meta-torbernite (2–10 µm) showing rectangular sections; the larger crystals have octagonal sections (sample ra–6); b) crystals of meta-zeunerite showing similar morphology as meta-uranospinite (sample ra–6). a b fig. 4 a) meta-uranospinite with an incorporated baryte inclusion (sample ra–6). the irregular grey spots are probably areas of dehydration with a partial loss of crystal water. tetragonal meta-uranospinite crystals have octagonal sections. different intensities of gray probably indicate ca–cu exchange; b) edx spectrum of the area where meta-uranospinite dominates over meta-zeunerite (sample ra–6). a b 169šćavničar et al.: uranium minerals in the radlovac series metasediments... 3.4. energy dispersive x-ray fluorescence analysis (edxrf) table 1 presents concentrations of the major, minor and trace elements measured in three samples from radlovac creek. xrf analysis of sample zmago–1 indicated a substantial concentration of uranium at 0.15%. the piko sample was characterized by extremely high concentrations of u, ba, as, and cu, more than hundred times (u, cu, ba) and more than two thousand times (as) higher when compared to normal values that could be obtained in sandstone sediments. arsenic was also highly enriched in the zbz material while u and ni were elevated approximately 20 and 10 times respectively compared to background values (zmago sample). elevated concentrations of k, ca, fe, and ti have also been established in this sample. the presence of all these elements can be related to the formation of uranium minerals, although ba has only been observed in baryte and not in the uranium mineral phases. copper forms meta-torbernite and meta-zeunerite, but also cuprite (and the primary chalcopyrite – figs. 6a and b). the source of titanium is the small, unevenly distributed needles of rutile up to 10 µm in length and less than 1 µm thick (sample zmago–1–4–3a). it is interesting to note that the presence of discrete nickel mineral fig. 5 a) discrete baryte crystals 10x18 µm in size. the uranium minerals were formed mainly around baryte grains, but baryte crystals also occur separately (sample ra–6). no uranium mineral grains are visible on this image; b) a more detailed view of fig. 5a. a b element sample piko ± zbz ± zmago ± k (%) 1.10 0.07 1.37 0.10 1.88 0.06 ca (%) 1.29 0.07 0.18 0.03 0.34 0.02 ti (%) 0.060 0.010 0.200 0.02 0.268 0.008 fe (%) 0.764 0.002 1.644 0.004 1.589 0.001 u (ppm) 1500 200 230 40 16 3 pb (ppm) 46 1 49 2 12 0.5 ba (ppm) 3900 300 390 30 630 40 as (ppm) 2200 200 2000 200 n.d. rb (ppm) 6.7 0.7 68.1 1.0 123.8 0.5 sr (ppm) 170.3 0.9 28.4 0.7 51.0 0.3 y (ppm) 27.8 0.8 138 2.0 40.4 0.5 zr (ppm) 131.9 0.7 525.0 2.0 432.2 1.0 mn (ppm) 320 20 620 40 330 10 co (ppm) 3.8 0.1 7.1 0.3 5.8 0.1 ni (ppm) 15 5 140 10 19 3 cu (ppm) 1550 60 13 2 15.7 0.9 zn (ppm) 167 3 42 3 39 1 table 1 elemental concentrations determined by edxrf system in three samples from the radlovac creek. 170 geologia croatica 60/2 phases was established, even though the concentration of ni is rather low. apart from its mineralogical significance, the identification of the uranium mineralization in the mt. papuk area is also important for a better understanding of the geology and formation of the radlovac series. unfortunately, the intricately intergrown uranium mineral fragments cannot be separated without substantial contamination by other phases, so the characteristics and content of structural (crystal) water cannot be measured with sufficient precision. the amount of crystal water in the uranium minerals is variable and changes with dehydration and rehydration, depending on the physico-chemical parameters of the environment in which it was formed, and/or whether it is currently in thermodynamic equilibrium. apart from the obvious significance of the partial pressure of water vapour, an important parameter of the reaction pathways leading to uranium mineral formation is the redox potential of the environment (bermanec et al., 2005). the identification of the oxidation state of uranium and the amount of crystal water in the uranium minerals would be of great importance for a better understanding of the conditions in which the radlovac series was deposited and the processes which have impacted on the chemical and mineralogical diagenesis of this rock series. 3.5. gamma spectrometry the activities of 40k, 232th, 226ra and 238u (bq/kg) as well as the 238u/226ra activity ratio are presented in table 2. concentrations of naturally occurring 40k range over an order of magnitude, indicating significant differences in the total potassium content (2.78% of potassium in sample ra–1 against 0.22% of potassium in sample zmago). similar differences in uranium activities/concentrations were also found. such differences indicate either compositional variation in the main minerals of the analyzed sandstones and/or intensive weathering processes. this is corroborated by the measured 238u/226ra activity ratio, which varies between 0.156 (in sample ra–1) and 1.224 as found in sample zmago. in their early research of the radlovac series, braun et al. (1983) maintained that uranium was not in equilibrium with its decay products. a high content of 226ra (a relatively short lived member of 238u natural decay chain) in comparison with uranium is very probably the result of recent (up to a few hundred thousand years), uranium leaching processes. however, 238u/226ra activity of 1,224 units in sample zmago indicates a zone where uranium was recently deposited with uranium enrichment. it seems that the highest uranium content of approximately 150 ppm, in sample ra6, is only ‘the remaining’ uranium after intensive leaching. on the basis of recent 226ra activity in that sample, it could be supposed that about 50% of the uranium content was weathered in the last few hundred thousand years. the uneven distribution of uranium minerals and accessory minerals in the investigated samples indicates that the protolyte was of inhomogenous composifig. 6 a) bundle of needle-like crystals of copper oxide, probably cuprite (sample ra–6); b) radiating crystal aggregates of copper oxide, probably cuprite (sample zmago–c). a b sample 40k 232th 238u/226ra 226ra 238u ra1 860.9±13.5 53.3±2.1 0.156 892.2±4.9 139.0±12.3 ra6 276.0±12.7 15.7±2.0 0.487 3 913±11 1 906±30.0 zmago 68.6±6.5 15.4±2.3 1.224 813.4±5.8 995.4±20.0 table 2 activities of 40k, 232th, 226ra, 238u (bq/kg) and the 238u/226ra activity ratio in the analyzed samples. 171šćavničar et al.: uranium minerals in the radlovac series metasediments... tion. this is further corroborated by the fact that several uranium mineral phases have formed, the phases not being fully separate but with variable composition within zoned mineral grains. all such phases appear to be in thermodynamic equilibrium. it was not possible to fully describe the zonations, since the thickness of such grains is very small. 4. conclusions the combination of methods used in this study enabled unambiguous determination of the u-bearing minerals of the radlovac series as meta-torbernite, meta-uranospinite and meta-zeunerite. these minerals have not been previously identified in croatia. further research will be devoted to identification of the nickel-bearing mineral phases and the determination of the oxidation state of the uranium ion in the uranium minerals – if appropriate samples become available, in which the separation of discrete uranium mineral phases will be possible. acknowledgements this work was supported by the ministry of science, education and sports of the republic of croatia, under grants no. 098–0982934–2713, 098–0982934–2715, 119–0000000–1158 and 098–0982934–2742. 5. references barišić, d. (1989): određivanje 235u and 238u gama-spektrometrijskom metodom pri energijama oko 186 kev [the determination of 235u and 238u by gamma-spectrometry method at energies around 186 kev – in croatian].– proceedings of 15th symposium of the yugoslav society for radiation protection (jdzz), prishtina, 91–94. barišić, d. (1996): dose rate conversion factors, soil thickness and their influence on natural background dose rate in air above carbonate terrains.– journal of environmental radioactivity, 31/1, 51–70. bermanec, v., wegner, r., kniewald, g., rakvin, b., palinkaš, l., rajić, m., tomašić, n. & furić, k. (2005): the role of uranium(v) ion in the chemical composition of meta-autunite from pegmatites of quintos de baixo, brazil.– neues jahrbuch für mineralogie, abhandlungen, 181, 27–38. braun, k. (1984): istraživanje urana u sr hrvatskoj (1978–1983) [prospecting for uranium in sr croatia (1978–1983) – in croatian].– savjetovanje “rezultati dosadašnjih i pravci daljnjih istraživanja nukelarnih sirovina”, zbornik radova, 62–98, beograd. braun, k., dravec, j., slović, v., crnogaj, s., valković, v. & makjanić, j. (1983): pojava mineralizacije urana na papuku i krndiji [uranium mineralisation at mt. papuk and mt. krndija – in croatian].– geološki vjesnik, 36, 111–115. brkić, m., jamičić, d. & pantić, n. (1974): karbonske naslage u papuku (sjeveroistočna hrvatska) [carboniferous deposits at mt. papuk (ne croatia) – in croatian].– geološki vjesnik, 27, 53–58. jamičić, d. (1976): structural fabric of the metamorphosed rocks of mt. krndija and the eastern part of mt. papuk.– bulletin scientifique jazu, section a, 21, 2–3. jamičić, d. (1979): prilog poznavanju tektonskih odnosa papuka i krndije [contribution to the knowledge of tectonic relationships of mts. papuk and krndija – in croatian].– zbornik radova, 4. godišnji znanstveni skup sekcije za primjenu geologije, geofizike i geokemije znanstvenog savjeta za naftu hazu, 199–206. jurković, i. (2003): metalogenija južne tisije – moslavačka gora, psunj, papuk, krndija [metalogenesis of southern tisija – moslavačka gora, psunj, papuk, krndija – in croatian].– rudarsko-geološko-naftni zbornik, 15/1, 1–17. oreščanin, v., mikelić, l., lovrenčić, i., barišić, d., mikulić, n. & lulić, s. (2006): environmental contamination assessment of the surroundings of the exferrochromium smelter dugi rat, croatia.– j. environ. sci. health a, 41/11, 2547–2555. oreščanin, v., mikelić, l., sofilić, t., rastovčan-mioč, a., užarević, k., medunić, g., elez, l. & lulić, s. (2007): leaching properties of electric arc furnace dust prior/following alkaline extraction.– j. environ. sci. health a, 42/3, 323–329. manuscript received july 13, 2007. revised manuscript accepted november 23, 2007. 172 geologia croatica 60/2 goetz.indd 1. introduction rudist bivalves rose to become the most important benthic carbonate producers during the late cretaceous. their great success in the occupation of shallow water marine environments was supported by morphological innovations (e.g. inequivalve morphology, elevator growth mode) (skelton, 1978), rapid shell accretion (growth) rates (steuber, 1996), a gregarious mode of life (skelton, 1979; gili et al., 1995) and prolific reproduction resulting in rapid horizontal dispersion. however, a thorough evaluation of the latter point still needs research on the reproduction and attachment pattern of rudists as well as on their initial growth behaviour. unfortunately, these features are difficult to larval settlement and ontogenetic development of hippuritella vasseuri (douvillé) (hippuritoidea, bivalvia) stefan götz evaluate in the fossil record because of the insufficient preservation of most samples. moreover, reproduction, attachment and ontogenetic development were spatiotemporal patterns, but research is usually based on the evaluation of sections that are two-dimensional. in an effort to overcome these limitations in general, techniques of 3-d reconstruction based on serial sectioning were developed quite early, beginning with born (1883) (see review in gaunt & gaunt, 1978). even the research on the ontogenetic development of adult rudist bivalves is mainly based on serial-sections. this technique is a valuable tool in evaluation of the intraspecific variability of rudist specimens, as shown by pons & vicens (1988), reali (1992), vicens (1994), simonpietri & philip (2000) among others. unfortunately, internal morphological features of great taxonomic significance (e.g., the myocardinal system) are not visible in cross-cuts far below the commissural plane. thorough taxonomic analysis in hippuritids is therefore only possible when the hinge and ligamental system are sectioned near the commissural plane. in consequence, the evaluation of the early development of a rudist animal should also be based on cross-cuts near the commissure. due to the lack of near-commissure sections of early ontogenetic stages, the evolution of taxonomically significant features (e.g. teeth, myophores, type of early secreted material) is poorly known. in addition, the development from the earliest juvenile growth stage to an adult shape was rapid and morphological evolution of the hinge and ligamental system is therefore limited to a few millimetres in earliest growth. nevertheless, klinghardt (1928, 1929), adkins (1931), skelton (1974) and breton (1996) reported on juvenile growth stages in rudist ontogeny. zapfe (1937) described some juvenile hippuritid specimens from the alpine gosau group. the smallest specimen observed was 2 mm high and 1.5 mm in diameter, thus the earliest growth stages were missing. later, vogel (1960) described juvenile hippuritids from southeastern france (la cadière d’azur) but the 20 juvenile specimens also range between 1.5 mm and 8 mm in diameter and they were extracted from the fines of marls, so the taxonomic assignment to adult specimens was uncertain. recently, skelton & gili (1991) reported on a spirogyrate attachment of hippurites socialis douvillé, and breton (1996) on a spirogyrate attachment of juvenile durania blayaci geologia croatica 56/2 123–131 3 figs. 1 pl. zagreb 2003 key words: cretaceous, palaeobiology, rudists, larvae, ontogeny. geological institute, university of karlsruhe (th), kaiserstraße 12, 76131 karlsruhe, germany; e-mail: stefan.goetz@bio-geo.uni-karlsruhe.de abstract an entire bouquet of some 250 specimens of hippuritella vasseuri (douville) was mapped three dimensionally, based on ascending serial sections spaced at 1 mm, in order to evaluate the earliest ontogenetic development in hippuritid rudists. this method supplied more than 5000 cross-cuts through rudist specimens of different ontogenetic stages beginning from <1 mm larval spat, up to fully grown “senior” rudists. based on near-commissure cross-sections of all ontogenetic stages, seven characteristic growth stages are distinguished, which show an increasing complexity of morphological features and a change in shell material composition. the complete transformation from a larval settling stage to adult-like morphology happened within the first 8–10 mm of vertical growth and comprised five stages. (1) the larval stage is defined by an undifferentiated aragonitic shell of about 0.3 mm diameter. (2) the “baby teeth” stage is still aragonitic but had a first hinge system. (3) the “first calcite” stage is characterized by the first occurrence of low magnesium calcite. (4) the “first pillar” stage shows weakly developed pillars and (5), the juvenile stage is of adult-like morphology but shows salient ornamentation and rapid diameter–size increase. subsequent development is dominated by the adult stage growth progress (6) with morphological continuity prior to a short lasting senior stage (7) and demise. 124 geologia croatica 56/2 125götz: larval settlement and ontogenetic development of hippuritella vasseuri... (toucas) specimens. unfortunately, this material was not suitable for an evaluation of the early myocardinal system. here, the ontogenetic development of the late cretaceous rudist hippuritella vasseuri (douvillé) is presented, based on numerous cross cuts through specimens from the earliest growth stage of <1 mm in height (0.3 mm diameter), up to adult specimens of >6 cm height (1.5 cm diameter). all growth stages were evaluated in situ, based on a sub-mm resolution 3-dimensional map of the entire bouquet, and the complete ontogenetic development of h. vasseuri could be described. 2. material and methods the hippuritella vasseuri (douvillé) bouquet was collected as a boulder in the river inn near the northern alpine gosau group of brandenberg, austria. after cutting the rock slab is 90 by 90 mm in diameter, 60 mm high and contains an almost monospecific association of about 250 in situ specimens (plate 1, figs. 1 and 2) which are densely packed and cover approximately 85% of the surface (fig. 1). adult individuals are about 10 mm in diameter. the growth axes of rudist individuals are parallel and the growth direction was considered to be vertical. in consequence, the original sedimentation plane was easily identified and polished to a mmstep ascending series of parallel horizons that were digitally scanned (plate 1, fig. 2). the pile of a total of sixty image files provides the dataset for a 3-dimensional picture of the rudist community with a resolution of 236.22x236.22x10 dots per cm. in horizontal view, all objects >0.05 mm, and in vertical view, objects >0.9 mm were evaluated. our data-set reveals the presence of 145 rudist settlers throughout the bouquet. a majority of them died at very juvenile ages and provide numerous nearcommissure sections of the early ontogenetic growth stages. the rudist packing density reaches 85–88% of the total area and is thus very high. dark brown homogenous wackestone fills interstitial areas and some rudist cavities throughout the sample. hence, a strong colour contrast is present between interstitial sediment and the pale white rudist shells which makes identification easy, even of tiny rudist individuals and larvae. dissolution seams and nests of neomorphic spar affected less than 3% of the sample volume. most rudist cavities are filled by dog-tooth spar cement and a second generation of blocky calcite spar, or they keep their primary porosities that are lined with dog-tooth spar. early marine calcitic cement may also be present covering the outer rims of rudist shells. the aragonitic (inner) hippuritid shell layer is diagenetically altered to blocky calcite spar, but the low magnesium calcite (lmc) outer shell layer still retains the original fibrous prismatic ultrastructure. fig. 1 figure shows section 30 in different views. the original scan is shown in greyscale (left side), drawing of low magnesium calcite shells (centre) and drawing that accentuates the 85% packing density within the bouquet (right side). the boxes show the cross-sections of some 70 rudist specimens of hippuritella vasseuri (douvillé). scale-bar is 1 cm. fig. 2 ascending series (drawing) of cross sections showing two specimens of hippuritella vasseuri (douvillé) that died very early. for original scans see plate 1, figs. 12 and 13. grey: original aragonitic shell; black: low magnesium calcite (lmc) shell. upper part: a: larval stage; b: baby-teeth stage; c, d: first calcite stage; e–g: first pillar stage. sectioning is slightly oblique. lower part: a: larval stage; b–d: baby teeth stage; e: first calcite stage. scale-bar is 1 mm. 124 geologia croatica 56/2 125götz: larval settlement and ontogenetic development of hippuritella vasseuri... 3. ontogenetic development based on our set of 60 high resolution scan images, we received more than 5000 cross-section pictures of rudist individuals. naturally, most of them are 1 mm ascending serial-cuts through adult rudist specimens, from apex to free valve. but we also received numerous serial-cuts through individuals that died early, and near-commissure cross cuts were obtained of individuals beginning from <1 mm in height and through subsequent specimens up to those achieving adult morphology. beginning with the first appearence of rudist settlers in thin section or scan, seven representative growth stages are distinguished (summarized in fig. 3), which are characterized by an increasing complexity of morphological features and a change in shell material composition. the complete transformation from the larval-settling stage to adult-like morphology occurred within the first 8–10 mm of vertical growth and comprise stages 1–5. subsequent development was dominated by the adult growth process (stage 6) and morphological continuity prior to a short lasting senior stage (stage 7) and demise. stage 1: larval stage (<1 mm height) (fig. 3; plate 1, figs. 3–5, 14) rudist settlers first appear in thin section or scan as small circles or dots of about 0.3 mm diameter nestling on the sides of adult specimens. they consist of recrystallized calcitic spar, probably former aragonite and lack a lmc (low magnesium calcite) outer shell layer. shell thickness is about 1/10 to 1/5 of the total diameter. the shell often appears reduced to non-visible thickness fig. 3 summary of the ontogenetic stages of hippuritella vasseuri (douvillé) described here. left column: growth stages, dimensions and scale-bars. centre column: drawings of selected examples. right column: short description of the salient features of each growth stage. see text for further explanations. 126 geologia croatica 56/2 127götz: larval settlement and ontogenetic development of hippuritella vasseuri... at the attachment area, maybe due to an oblique cut through a spirogyrate shell shape. the shell is undifferentiated and shows no hinge or ligamental system. this initial aragonitic growth stage probably represents the prodissoconch of the rudist animal. stage 2: baby teeth stage (1–3 mm height) (fig. 3; plate 1, figs. 6–8, 15, 16) this growth stage is characterized by a thicker, still exclusively aragonitic wall, whereas the attachment area is often thinned and first sights of a hinge system appear. the specimens are now 0.6– 0.9 mm in diameter. a simple developed myocardinal system is visible in thin section and scan. it is characterized by one, two or three slightly elliptical cavities that are filled by matrix. these cavities likely correspond to myocardinal elements of the left valve (i.e., posterior myophore, posterior tooth and anterior tooth). the earliest hinge system is already a pachydont one, and it is unlikely that a change in the organisation of myocardinal elements (e.g. from early “conservative” taxodont to pachydont) took place during the earliest ontogenetic development. stage 3: first calcite stage (2–4 mm height) (fig. 3; plate 1, figs. 9–11) this growth stage is characterized by the first occurrences of calcitic shell-parts. the specimens are now 0.8–1.3 mm in diameter. the myocardinal elements of the “baby teeth” stage remain unchanged. the first signs of a secretion of low magnesium calcite (lmc) appear at the position of the later ligamental ridge and the pillars. these lense shaped lmc parts are embedded in the aragonitic shell and subsequently move to the external side. the transition to the next stage took place more or less during the formation of an almost closed lmc outer shell rim. stage 4: first pillar stage (3–7 mm height) (fig. 3; plate 1, fig. 17) this growth stage may be synonymous to the “worm stage” sensu adkins (1931). it is characterized by the development of the ligamental ridge and the two pillars. the diameters of the specimens now range between 1 mm and 2 mm. a closed outer lmc shell layer is now established and the ligamental ridge, as well as the pillars, are represented by thickenings of the outer shell layer. later, indentations develop and mark the positions of the ligamental ridge and the pillars at the exterior. these indentations appear slightly prior to the first elements of ornamentation. stage 5: juvenile stage (6–10 mm height) (fig. 3; plate 1, fig. 18) in this stage, a strong ornamentation is apparent and the myocardinal system is fully developed. the specimens are now between 2.5 and 5 mm in diameter. in this growth stage, the growth is conical and size increase is rapid. the former indentations are now furrows at the exterior, marking the ligamental ridge and pillars. the thickness of the lmc shell layer increased significantly and salient ribs cover the exterior of the specimens. stage 6: adult stage (10–>60 mm height) (fig. 3) the adult stage is characterized by a change from conical to cylindrical growth. the specimens are now between 10 mm and 15 mm in diameter. the lmc shell is still thick, but the external ribs appear less salient due to the size increase of the specimens whilst the size of the ribs is still the same as in the juvenile growth stage. most of the growth history of the rudists took place in the adult growth mode. in this stage, many of the former settlers show a thinning of the outer shell layer at the area of contact with the substratum specimen. interestingly, the substratum specimens also show these reductions in shell thickness at the area of contact with the settling specimen. stage 7: senior stage (topmost 3–5 mm of final height) (fig. 3) the senior growth stage is characterized by a reduction of the ornamentation and the thinning of the lmc outer shell layer. the specimens are between 10 mm and 15 mm in diameter. nevertheless, the observed thinning of the outer shell layer could be a result of cross-cutting of the topmost right (attached) valve, where (in vertical section) the shell wedges out towards the commissure. this is a feature that is probably present in each growth stage of hippuritella. together with the observation of reduced ornamentation, however, a thinning of the outer shell layer defines fully grown rudist specimens shortly before decline. 4. discussion the in situ evaluation of a h. vasseuri bouquet, based on serial sectioning supplied numerous sections through rudist individuals of different ontogenetic stages. based on these cross-cuts the complete ontogenetic development of the h. vasseuri shell could be described. although klinghardt (1928, 1929); adkins (1931), zapfe (1937), vogel (1960), skelton (1974), and breton (1996) described juvenile rudists, their observations were limited to specimens greater than 1 mm diameter. hence the ontogenetic development between the settlement of the larvae and the building of the dissoconch still needed evaluation. 126 geologia croatica 56/2 127götz: larval settlement and ontogenetic development of hippuritella vasseuri... ontogenetic development and phylogenetical implications the smallest rudist individuals evaluated here are 0.3 mm in diameter (see plate 1, figs. 3–5, 14) and appear in thin section and scan as small dots or circles, originally made of aragonite. they show no internal differentiation and likely represent a growth state of only days or weeks after larval settlement. each of the evaluated 145 settlers was nestling on a neighbour´s right valve but none was found nestling on a bioclast. the observation of a preferred attachment to adult specimens is also reported by zapfe (1937) on hippuritids and by adkins (1931, p. 87) on radiolitids (eoradiolites): “...tightly attached to the substratum, usually an adult rudistid...”. after settling, the exclusively aragonitic shell rapidly developed the first hinge system within the first mm of vertical growth (the “baby teeth” stage). this hinge system is already comparable to the adult hinge except for the absence of ligamental or pillar structures (see figs. 2, 3). cross-cuts through the free valve were not obtained at this growth stage, but the presence of teeth sockets and a posterior myophore socket indicate the existence of a free valve. this agrees with observations of zapfe (1937) who reported on a juvenile hippuritid of 2 mm in length with preserved free valve apparently devoid of a pore and canal system. moreover, the projection of the posterior myophore into a “pocket” implies a relationship with rudist groups that also show this caprotinid-type myophoral arrangement (skelton, pers. comm.). the cladistic analysis of rudist phylogeny by skelton & smith (2000) points to the albian polyconitid tepeyacia as a sistergroup of hippuritids. the intriguing similarity of the h. vasseuri “baby teeth” myocardinal arrangement presented here with tepeyacia described by skelton & smith (2000, p. 112) is additional evidence for this relationship. subsequent development of h. vasseuri is characterized by the first appearance of lmc shell material, the “first calcite” growth stage. lense shaped areas consisting of lmc appear embedded in the aragonitic shell and mark the position of the later ligamental ridge and the pillars (see figs. 2, 3; plate 1, figs. 9–11). because of this change in shell secretion and the presence of first position markers of the main adult shell features (e.g. ligamental ridge, pillars) this transition is interpreted to represent the prodissoconch/dissoconch transition in bivalve ontogeny. in the later development of h. vasseuri the main adult morphological features evolve. the lmc shell layer is completed and covers the exterior of the shell. pillars are still absent until a height of about 3 mm. subsequently, first pillars evolve and appear as bulged lmc shell parts, similar to those in tepeyacia (see skelton & smith, 2000, fig. 11b). this additional morphological resemblance to the albian polyconitid again implies a phylogenetic relationship between hippuritidae and tepeyacia as supposed by skelton & smith (2000). vogel (1960) recognized the presence of pillars in juvenile hippuritid specimens of more than 1.5 mm diameter and also described them as swelled lmc shell parts and not as indentations as in adult specimens. it seems that swelled lmc shell parts (“proto-pillars”) were a common morphological feature in the early growth stages of many hippuritids. here, h. vasseuri shows indentations (folds) later during the transition to the “juvenile stage” when the ornamentation evolves. during this stage, juveniles strongly increase in diameter, they acquire a thick lmc shell layer and develop prominent ribs (see fig. 3; plate 1, fig. 18). this is presumed to reflect competition for horizontal space and oversized ribs may have helped them to claim additional horizontal space. after reaching the adult size of about 10 mm in diameter, further growth is cylindrical with no further increase in diameter. the ribs are still of the same size as in the juvenile stage, but appear now less salient because of a significantly increased diameter. most of the former settlers now show a thinning of the outer shell layer at the area of contact with the substratum specimen. interestingly, the substratum specimens also often show these reductions in shell thickness at the area of contact with the settling specimen. this indicates a synecological in vivo interaction of both specimens. many settlers must have caught up in growth with the substratum specimen, indicating an attachment place not too far below the commissural line. the rudist specimen is now tightly inset in the bouquet framework and cemented at least to one neighbour. after a vertical growth of several centimetres without further horizontal size-increase the specimens of h. vasseuri change morphology for the last time. zapfe (1937, p. 91) reported on senior hippuritids which show reduction of ornamentation. this is confirmed here on h. vasseuri. the ribs become smooth and the outer lmc shell layer becomes thinner (fig. 3). this is interpreted to represent the “senior stage”, a phase of reduced growth and shell secretion prior to death. nevertheless, the observed thinning of the outer shell layer could also be a result of cross-cutting of the topmost right (attached) valve, where, in vertical section, the commissure rim shows a steep inclination towards the body cavity. this is a feature that is probably present in each growth stage of hippuritella. attachment and early growth the juvenile eoradiolites specimens described by adkins (1931), show a spirogyrate initial growth within the first 3.5 mm of shell diameter (the “coiled stage”). this feature was also described by skelton (1979) on hippurites socialis. however, a spirogyrate initial growth mode is not clearly observable on the specimens described here. this is due to the limited vertical resolution of 1 mm, and the first 0.9 mm of (spirogyrate?) growth still needs evaluation. after the first mm, however, the prodissoconch changed the growth direction immediately to an upright position 128 geologia croatica 56/2 129götz: larval settlement and ontogenetic development of hippuritella vasseuri... after attachment, yielding a tube-like growth mode. the second eoradiolites growth stage of adkins (1931, p. 87), the “worm stage” described as “...small, smooth, worm-like, cylindrical tubes...” provides an analogy to the early growth mode of h. vasseuri. although adkins (1931) described his “worm stage” as the second growth stage of eoradiolites, he considered that slender individuals or species may have only had a “worm stage” initial growth. however, this observation was probably also biased by insufficient resolution or preservation of the earliest growth stage. 5. conclusions the ontogenetic development of hippuritella vasseuri (douvillé) is described here, starting from a growth stage shortly after settling of the larva. subsequently, from larva to decline, seven morphologically different growth stages are distinguished (fig. 3). within the first 6–10 mm of vertical growth all significant shell features of the adult animal are developed. the first growth stages in this 6–10 mm comprise the aragonitic larval stage and aragonitic “baby teeth” stage, the “first calcite” stage and the “first pillar” stage. the morphological resemblance of h. vasseuri during these growth stages to the albian polyconitid tepeyacia (posterior myophore socket, “proto-pillars”) imply a phylogenetic relationship between the hippuritidae and tepeyacia. the prodissoconch/dissoconch transition in bivalve ontogeny is presumed to be analogous to the “baby teeth” stage/“first calcite” stage transition. generally, h. vasseuri is highly variable in terms of the duration of each early growth stage or in the speed of growth of the early stages, respectively. with the beginning of the development of ornamental features (e.g., ribs) h. vasseuri bears all the adult-like shell features and stays morphologically quite stable for most of its life (e.g., the juvenile stage and the adult stage). a final morphological change is observable prior to the decline of the h. vasseuri specimens. ornamentation is reduced and the outer lmc shell layer is thinned, described here as the “senior growth” stage, and probably indicates a phase of reduced shell accretion on the brink of death. acknowledgements i am grateful to elke hermann, sascha schmid and stephan unrein for preparation, scanning and image analysis. peter skelton and an anonymous reviewer provided valuable suggestions that greatly improved the final paper. financial support was granted by the deutsche forschungsgemeinschaft (dfg) project go1021/2–1. 6. references adkins, w.s. (1931): new rudistids from the texas and mexican cretaceous.– the university of texas bulletin, 3001, 77–136. born, g. (1883): die plattenmodellir methode [the method of modelling with plates – in german].– archiv mikroskopischer anatomie (breslau), 22, 584–599. breton, g. (1996): un groupe de juvéniles conservés dans la cavité palléale d´un rudiste radiolitidae durania blayaci (toucas, 1909) du cénomanien du havre (seine–maritime, france) [a group of juveniles, preserved in the pallial chamber of the radiolitid rudist durania blayaci (toucas, 1909) from the cenomanian of havre (seine-maritime, france) – in french].– c.r. acad. sci. paris, 322, iia, 493–500. gaunt, w.a. & gaunt, p.n. (1978): three dimensional reconstruction in biology.– pitman medical press, kent, 174 p. gili, e., masse, j.p. & skelton, p.w. (1995): rudists as gregarious sediment-dwellers, not reef-builders, on cretaceous carbonate platforms.– palaeogeography, palaeoclimatology, palaeoecology, 118/3–4, 245–267. klinghardt, f.i. (1928): über sehr frühe entwicklungsstadien eines rudisten [on very early ontogenetic stages of a rudist – in german].– neues jahrb. für min., geol, u. pal., beil. bd. (b), 60, 173–178. klinghardt, f.i. (1929): die stammesgeschichtliche bedeutung, innere organisation und lebensweise von eoradiolites liratus conrad sp. [the phylogenetical significance, internal organisation and way of life of eoradiolites liratus conrad sp. – in german].– palaeontographica, 72, 95–101. pons, j.m. & vicens, e. (1988): campanian and maastrichtian rudists from southern valencia province, south east spain.– 1st int. conf. on rudists, serb. geol. soc. spec. publ., 2 [issued as reprint from volume in press]. reali, s. (1992): preliminary morphometric analysis for hippuritids taxonomy.– geologica romana, 28, 91–103. simonpietri, g. & philip, j. (2000): relations ontogenese–phylogenese chez les rudistes; l’exemple des hippuritidae gray, 1848 [the ontogenic-phylogenic relationship in rudists; the hippuritidae gray, 1848 example – in french].– comptes rendus de l’academie des sciences, serie ii. sciences de la terre et des planetes, 330/10, 717–724. skelton, p.w. (1974): aragonitic shell structures in the rudist biradiolites, and some palaeobiological inferences.– géologie méditerranéenne, 1/2, 63–74. skelton, p.w. (1978): the evolution of functional design in rudists (hippuritacea) and ist taxonomic implications.– phil. trans. r. soc. lond., b(284), 305–318. skelton, p.w. (1979): gregariousness and proto-cooperation in rudists (bivalvia).– in: larwood, g. & rosen, b.r. (eds.): biology and systematics of colonial organisms. syst. ass. spec., london, new york, 257– 279. 128 geologia croatica 56/2 129götz: larval settlement and ontogenetic development of hippuritella vasseuri... skelton, p.w. & gili, e. (1991): palaeoecological classification of rudist morphotypes.– 1st int. conf. on rudists, serb. geol. soc. spec. publ., 2, 265–287. skelton, p.w. & smith, a.b. (2000): a preliminary phylogeny for rudist bivalves: sifting clades from grades.– in: harper, e.m., taylor, j.d. & crame, j.a. (eds.): the evolutionary biology of the bivalvia. geol. soc. spec. pub., 97–127. steuber, t. (1996): stable isotope sclerochronology of rudist bivalves: growth rates and late cretaceous seasonality.– geology, 24, 315–318. vicens, e. (1994): estudio de la fauna de rudistas (hippuritidae y radiolitidae) de los materiales cretácicos del pirineo oriental: implicaciones bioestratigráficas [a study on the rudist fauna (hippuritids and radiolitids) from cretaceous materials of the eastern pyrenees: biostratigraphical implications – in spanish].– unpubl. phd thesis, univ. auton. barcelona, barcelona, 255 p. vogel, k. (1960): zur struktur und funktion der “siphonalpfeiler” der hippuriten (lamellibranchiata) [on the texture and function of the sipho-pillars in hippuritids (lamellibranchiata) – in german].– paläontologische zeitschrift, 34/3-4, 257–294. zapfe, h. (1937): paläobiologische untersuchungen an hippuritenvorkommen der nordalpinen gosauschichten [palaeobiological investigations on hippuritid-occurrences of the north-alpine gosau-strata – in german].– zoologisch–botanische gesellschaft wien, 136/137, 73–121. manuscript received march 17, 2003. revised manuscript accepted november 04, 2003. 130 geologia croatica 56/2 131 plate 1 1 original sample of the hippuritella vasseuri (douvillé) bouquet. scale-bar is 1 cm. 2 sample embedded in epoxy, resting on the scanning device. the computer monitor displays a part of the scanned horizon. 3–11 original scans, highly magnified and therefore of low resolution. 3–5) settlers in “larval stage”, nestling on an adult shell. no internal differentiation, former aragonitic shell. scale-bars are 0.1 mm. 6–8) specimens in “baby teeth” stage. a hinge system is developed as shown by small tooth-sockets. scale-bars are 0.5 mm. 9–11) specimens in “first calcite” stage. lmc shell parts appear on the position where pillars appear later. scale-bars are 0.5 mm. 12–13 ascending series (original scans) of cross sections showing two specimens of hippuritella vasseuri (douvillé) that died very early. for fair drawings see fig. 2. 12) a: larva stage; b: “baby-teeth” stage; c–d: “first calcite” stage; e–g: “first pillar” stage. 13) a: larval stage; b–d: “baby teeth” stage; e: “first calcite” stage. scale-bars are 1 mm. 14–18 thin section photomicrographs. 14) larval stage. scale-bar is 0.1 mm. 15–16) “baby teeth” stages. scalebar is 0.5 mm. 17) “first pillar” stage: pillars weakly developed, no ornamentation. scale-bar is 1 mm. 18) juvenile stage, thick lmc shell layer, prominent ribs. scale-bar is 1 mm. 130 geologia croatica 56/2 131götz plate 1 132 geologia croatica 56/2 surlyk & noe-nygaard.indd a giant sand injection complex: the upper jurassic hareelv formation of east greenland finn surlyk and nanna noe-nygaard 1. introduction sandstone intrusions have always caught the attention of geologists and are in many cases highly spectacular due to the contrast between light-coloured intrusive sandstones and dark host mudstones. in recent years it has become increasingly clear, that large, irregular bodies of massive sandstone may also be of intrusive origin, but the timing and nature of remobilization of the primary deposit, and of the subsequent injection are less well understood. it is also being recognized that remobilized and injected sands, mainly of relatively deep-water origin, may form important hydrocarbon reservoirs, which are difficult to interpret. the upper jurassic hareelv formation of jameson land, east greenland is probably the world’s largest intrusive sandstone complex (surlyk, 1987; surlyk & noe-nygaard, 2001). it comprises sandy submarine density flow deposits, which have undergone post-depositional remobilisation, liquefaction and subsequent intrusion in the surrounding compacted muds and mudstones. the sediments were sourced from shelfedge wedges and deltas. interpretation of the depositional processes is, however, hampered by destruction of the primary sedimentary structures during remobilisation and liquefaction. however, a spectrum of sedimentary density flows involving hyperconcentrated and concentrated density flows (in the sense of mulder & alexander, 2001) can be interpreted, depending on the position on the slope, degree of confinement and travel distance (surlyk & noe-nygaard, 2001; bruhn & surlyk, in press). deposition took place in steep-sided slope gullies or in a non-confined baseof-slope and basinal setting. the aim of this study is to review the main processes acting during sand intrusion, and to interpret the possible causes. the extensive intrusive complex of the hareelv formation serves as a key example in order to facilitate the interpretation of similar subsurface examples. 2. late jurassic geological setting, palaeogeography and facies patterns the upper oxfordian−volgian hareelv formation was deposited in the southern end of the mesozoic rift-basin of east greenland during the jurassic rift climax. the geologia croatica 56/1 69–81 15 figs. zagreb 2003 key words: sediment remobilisation, intrusion and injection, sandstone dykes and sills, upper jurassic, hareelv formation, east greenland. geological institute, university of copenhagen, øster voldgade 10, dk-1350 copenhagen k, denmark; e-mail: finns@geo.geol.ku.dk; nannan@geo.geol.ku.dk abstract a major intrusive sandstone complex of late jurassic age is spectacularly exposed in jameson land, east greenland. it is probably the largest in the world, and covers an area of 55x70 km with a thickness of 200–400 m, and forms the upper oxfordian–volgian hareelv formation. the complex consists of black basinal mudstones and highly irregular sandstone bodies, dykes and sills. the sand was derived from collapse of the front of sandy shelf-margin wedges, which triggered hyperconcentrated to concentrated density flows, and deposited massive sands further down the slope, at the base-of-slope and in the basin. the sand of some flows was loaded into the slope muds while elsewhere it flowed in steep-sided gullies formed by retrogressive slumping of the slope muds. all sand bodies were liquefied subsequent to burial and the sand was intruded into the surrounding black compacted muds and mudstones. intrusion took place repeatedly over a long time interval, in environments ranging from very shallow to relatively deep burial, and the primary sediment structures of the sands were generally lost during these processes. it is rarely possible to determine the degree of post-burial remobilization but it ranges from rather small-scale modifications to wholesale liquefaction and out-of-place intrusion of the sand over many tens of metres. sandstone dykes and sills occur ubiquitously and were emplaced by all combinations of stoping and dilation. the intrusive sand bodies range in dimensions from centimetres to many hundreds of metres. deposition took place during the most important mesozoic rift event in east greenland and the pervasive remobilization and liquefaction of all sand bodies in the hareelv formation is interpreted as having been caused mainly by cyclic earthquake shocks. additional important factors were slope shear stress, build up of pore pressure due to loading, slumping, upwards movement of pore waters expelled from the compacting muds, and also possibly of biogenic and thermogenic gas. the hareelv formation is an excellent field analogue for deeply buried hydrocarbon reservoirs, which have been modified by remobilization and injection of the sands. 70 geologia croatica 56/1 71surlyk and noe-nygaard: a giant sand injection complex: the upper jurassic hareelv formation... formation is 200−400 m thick, extends over an area of 55x70 km and is well exposed (figs. 1 and 2). the upper oxfordian−kimmeridgian part of the formation belonging to the katedralen member is only represented by slope and basinal deposits, and correlative shallowmarine sediments are not preserved, whereas the volgian part includes a complete shelf-slope-basin transition. in late jurassic time a northern sand-dominated coastal and shallow shelf area was separated from the southern mud-dominated basin by a roughly east−west trending shelf-slope break in central jameson land (fig. 2). deltaic and shallow-marine sands reached the shelf edge during successive progradational episodes, and shelf edge failure triggered flows of sand, which were deposited as massive sand bodies on the slope, at the base-of-slope and on the basin floor (figs. 3 and 4). the maximum late jurassic transgression took place in the kimmeridgian, and deep-marine conditions existed south of the shelf-slope break in jameson land throughout the late oxfordian−kimmeridgian during deposition of the hareelv formation. the hareelv formation consists of clean sandstone and dark-grey to black mudstone (fig. 5). the mudstone is organic-rich, in part with excellent hydrocarbon source rock potential. it is laminated, and has a toc content up to 12%, but the amount of marine kerogen is lower, at about 4% (christiansen et al., 1992). the mudstones contain ammonites, the bivalve buchia and a sparse trace fossil fauna including chondrites. fossil wood and disseminated plant debris is common. deposition took place in relatively deep water, well below storm wave base under dysaerobic conditions, and the mudstones represent the basinal background deposits of the formation. thin planar sandstone turbidites occur interbedded with the mudstones, but form a volumetrically insignificant part of the formation. they consist of beds of muddy sandstone, a few millimetres to about one centimetre thick, showing classical ta, tab, tb, tbc and tc divisions. they were deposited from low-density turbidity currents. the most conspicuous facies in the formation consists of massive sandstone forming extremely irregular sandstone bodies. they occur throughout the formation and are interbedded with the basinal mudstones in a highly complex way. they are up to 50 m thick and up to many hundreds of metres wide, but thicker amalgamated sandstone bodies also occur (figs. 6 and 7). the sandstone/mudstone ratio is approximately 1:1 in the upper oxfordian−kimmeridgian part of the formation. the sandstones are massive, mainly well sorted, fine to medium-grained and quartzose with a relatively high content of mica, some glauconite and occasional reworked fossils. mudstone clasts are common and range in size from minute chips, over metre-sized flakes to slabs more than ten metres long. the clasts are mainly angular and commonly book-shaped with flat surfaces following the primary lamination. some clasts may have curved shapes caused by plastic deformation but this is less common. amalgamation surfaces occur in many sandstone bodies and may be loaded, gently curved or flat and are commonly outlined by irregular bands of mudstone chips. the only type of structure is a diffuse, sub-horizontal wavy consolidation lamination in some of the thicker bodies (fig. 8). dish structures and irregular water escape pipes occur but are not common. the sandstones are clean with sharp boundaries to the mudstones, and muddy sandstones are extremely rare (figs. 5, 7, 10, 11 and 12). fining/coarsening or thinning/thickening-upward successions are notably absent. sandstone–mudstone boundaries are extremely irregular. the base of the sandstone bodies is always sharp, commonly loaded, flat and horizontal for up to a few metres, and rarely, if ever faulted. some of the thicker sandstone bodies have vertical or even overhanging margins, and were deposited in steep-walled gullies eroded into the slope muds; the fill was commonly modified by loading of sand into the slope and basinal muds. the massive sands are interpreted as having been deposited from hyperconcentrated to concentrated sedimentary density flows, tapping a well-sorted fig. 1 pre-drift map showing the position of jameson land (asterisk) in late jurassic time and the main basin-controlling faults. 70 geologia croatica 56/1 71surlyk and noe-nygaard: a giant sand injection complex: the upper jurassic hareelv formation... sand source formed by current and wave winnowing of sand-dominated delta front and shelf sediments (figs. 3 and 4). a downslope transition from massive gully fill sandstones transported and deposited from confined flows, to sheet-like but still massive sandstones deposited at the base-of-slope from unconfined flows, occurs in the lower−middle oxfordian olympen formation (larsen & surlyk, 2003; bruhn & surlyk, in press), and has also been suggested for the hareelv formation (surlyk, 1987). this indicates that transfig. 2 palaeogeographic map of east greenland in the late oxfordian. late oxfordian ~ , i, i ~ 1 n -i~ --.\ , ~ .. ii' -• ,0' " • -i: -._--, ., in -:.:.:, o nearshore heterolilhs and sandstones ~ offshore heterolithic mudstones • deep-water mudstones ~ ill 0 ~ -~ ~ ,. guiy _ m"" f 72 geologia croatica 56/1 73surlyk and noe-nygaard: a giant sand injection complex: the upper jurassic hareelv formation... port and deposition took place from sediment flows undergoing downslope transformation from hyperconcentrated to concentrated density flows. the gullies probably originated as slides and the slide scars were subsequently modified by retrogressive slumping, which cut backwards into the front of the shelf-margin wedge where they acted as downslope conduits for a few sand flows, as indicated by the presence of amalgamation surfaces in the sandstone bodies (figs. 3 and 4). levee deposits are notably absent, indicating that the flows and the gullies are independent phenomena and that the latter did not serve as long-term transport conduits for the flows. 3. post-depositional remobilization of the sands the upper boundary of the more sheet-like sandstone bodies steps up and down on several scales ranging from fig. 4 diagrams showing sandy progradation to the shelf edge, slope failure, gully formation by retrogressive slumping, imitation of hyperconcentrated to concentrated sandy density flows, and deposition of pod-shaped slope gully sands and sheet-like base-of-slope lobes. fig. 3 depositional model for the upper oxfordian–kimmeridgian katedralen member of the hareelv formation. 72 geologia croatica 56/1 73surlyk and noe-nygaard: a giant sand injection complex: the upper jurassic hareelv formation... millimetres to metres (figs. 6 and 7). many of the larger sandstone bodies have a ridge-like or mounded upper surface, quite commonly with a dip of up to 60º (figs. 5, 9 and 12). the mounded tops were formed by intrusive diapirism, as the original depositional upper surface of the sands was undoubtedly flat, reflecting their density flow origin. the bedding in the mudstones is dominantly horizontal except for layers immediately adjacent to the larger sandstone bodies. faults have not been observed along the steeply dipping sandstone–mudstone boundaries and the mudstones did not slide off the mound along any type of detachment plane. sandstone dykes and sills occur throughout the formation, commonly in great density and showing a high degree of complexity (figs. 11−14). the sills are comfig. 5 log through part of the hareelv formation (katedralen member) in southern jameson land. note the disorganised nature of the member, the stacked gully fill sandstones at 470−505 m, and mounded top of sandstone beds at 532 m. all sand bodies have undergone remobilization and injection, and all the thin sandstone beds are sills. 74 geologia croatica 56/1 75surlyk and noe-nygaard: a giant sand injection complex: the upper jurassic hareelv formation... fig. 6 large pod-shaped sandbody composed of several amalgamated massive deep-water sandstone units. the sands underwent post-burial remobilisation and liquefaction and were intruded into adjacent mudstones. the sandstone body to the upper left is about 50 m thick. upper oxfordian, katedralen member, hareelv formation, southern jameson land. fig. 7 sheets of massive sandstone intercalated with black mudstones. note highly irregular upper surfaces of the sandstone bodies, which step op and down over several metres. this reflects post-depositional remobilisation, liquefaction, fluidization, and injection of the original density flow deposit. katedralen member, hareelv formation, southern jameson land. fig. 8 thick, massive sandstone body showing consolidation lamination. this facies is typical of the katedralen member, hareelv formation. southern jameson land. 74 geologia croatica 56/1 75surlyk and noe-nygaard: a giant sand injection complex: the upper jurassic hareelv formation... monly transgressive on all scales, and they vary in thickness from millimetres to many metres. thicker sills are transitional to remobilized sandstone bodies and there is no clear distinction between the two groups (figs. 11 and 12). dykes and sills may occur in such a high density that they occupy the bulk of the sediment volume, so that the host mudstone is only represented by displaced and irregular, sometimes folded laminae and lamina sets (fig. 12, lower part). sandstone dykes are commonly ptygmatically folded, due to post-intrusive compaction of the surrounding mudstones, which were only slightly compacted at the time of intrusion (figs. 12 and 14). other intrusions are completely irregular, winding and curved, also reflecting intrusion in a poorly consolidated mudstone under shallow burial. some dykes and sills show roughly orthogonal relations where the sills follow bedding planes in the mudstones, whereas the dykes are subvertical, showing that the mudstones were sufficiently compacted at the time of intrusion to allow development of joints (figs. 11 and 13). extremely variable intrusion geometries commonly occur at the same stratigraphic level, reflecting repeated intrusive events under different depths of burial. this is also shown by cross-cutting relationships and different degrees of compaction folding (figs. 12 and 14). systematic geometrical relationships between dykes and sills and the larger sandstone bodies have not been identified. dense networks of dykes and sills seem to occur completely randomly with respect to the sandstone bodies. examples of injection complexes above large mounded sandstone bodies, as have been interpreted from the palaeogene of the north sea (dixon et al., 1995) have thus not been observed. the massive nature of all the sandstones, their extremely irregular geometries, the dramatic changes in thickness over short distances, the loaded bases and margins of the sandstone bodies, the ubiquitous occurrence of sandstone dykes and sills, and the occasional presence of water escape structures indicate that the sands of the hareelv formation have been remobilized and liquefied subsequent to deposition. the liquefaction process included fluidization resulting from pore fluid movement, liquefaction caused by cyclic shear stress, and shear liquefaction resulting from the application of a shear stress across a sand body (cf. nichols, 1995). these processes interact in the natural environment and cause the sands to become more susceptible to liquefaction (nichols, 1995). the importance of large-scale loading in the deformation of the hareelv sandstone bodies indicates that liquefaction was caused by shock or vibration. liquefaction by fluidization played an additional, albeit minor role in additions to shocks. the extreme irregularity of the sandstone bodies of the intrusive complex does not allow identification of linear ridges, or convolute lamination with preferred orientations, indicative of liquefaction by slope shear stress (cf. anketell et al., 1970). measured sections show that in most cases it is extremely difficult to impossible to distinguish primary, massive sands, from sands which have undergone inplace liquefaction followed by only minor remobilization and injection, or from completely remobilized and far-travelled intrusive sands (figs. 5, 10, 11 and 12). even apparently subhorizontal, thick massive beds, looking like normal primary beds, can commonly be shown to be of an intrusive nature when traced laterally (figs. 11 and 12). the lack of injection complexes above mounded sand bodies show that breakage of the mudstone seal and outflow of liquefied sand on the seafloor did not take place. liquefaction, remobilization and injection of sand into the surrounding mudstones thus always took place after burial, ranging from several metres to tens of metres (fig. 15). the regular, platy shape of most mudfig. 9 massive sandstone body of the type commonly showing a mounded top. person at the base for scale. katedralen member, hareelv formation, southernmost jameson land. 76 geologia croatica 56/1 77surlyk and noe-nygaard: a giant sand injection complex: the upper jurassic hareelv formation... stone clasts shows that the surrounding mudstones had undergone substantial compaction at the time of remobilization. the ubiquitous presence of load structures, compaction folded dykes, flow marks on sandstone– mudstone interfaces, and the occurrence in some sand bodies of plastically deformed and sheared mudstone clasts, indicate on the other hand that liquefaction and injection also took place at shallower depths. the fact that all sandstone bodies in the formation have undergone remobilization, liquefaction, and injection and the common presence of cross-cutting dykes and sills show that liquefaction took place throughout deposition of the formation, i.e. from the late oxfordian through the volgian. remobilization, liquefaction and injection were caused by shocks and vibrations and to a lesser degree by fluidization: it is not possible to directly prove the influence of gravitational shear stress. the triggering processes were active more or less continuously over a time interval of at least 10 million years in the late jurassic, corresponding to the climax phase of the main mesozoic rift event in the north sea−north atlantic region. in east greenland, rifting was initiated in mid jurassic time, and the rift climax seems to have occurred in the late oxfordian−kimmeridgian, whereas volgian deposition was dominantly shallow marine, reflecting a reduced subsidence rate and infilling of the basin (surlyk & noe-nygaard, 1991; surlyk, 2003). fig. 10 massive, gully-fill sandstone showing stepped margin modified by loading. katedralen member, hareelv formation, southern jameson land. 76 geologia croatica 56/1 77surlyk and noe-nygaard: a giant sand injection complex: the upper jurassic hareelv formation... the pervasive liquefaction of all sand bodies in the hareelv formation is thus interpreted as having been caused by cyclic earthquake shocks during an extended period of intensive rifting. additional important factors were the buildup of pore pressure, upward movement of pore waters expelled from the compacting muds, presence of mudstone seals, and slope shear stress. there is no evidence for migration of hydrocarbons generated in older rocks in jameson land, and the lack of faults cutting the mesozoic succession, and the relatively great thickness of the hareelv formation indicate that the migration of gas to shallow levels along fault conduits fig. 11 thick massive sheet sandstones modified by remobilisation and intrusion. the upper sheet shows preserved consolidation lamination in the central part and to the lower right, indicating only minor remobilisation of this bed. the mudstone unit in the lower part of the section shows a complex network of thin sandstone dykes and sills. the roughly orthogonal relationships indicate that intrusion in this part took place after burial and compaction of the mudstone. the top of the lower sandstone sheet steps up and down and shows small faults. katedralen member, hareelv formation, southern jameson land. 78 geologia croatica 56/1 79surlyk and noe-nygaard: a giant sand injection complex: the upper jurassic hareelv formation... was unlikely. degradation of gas hydrates as a possible cause has not yet been tested, but the fact that liquefaction took place throughout a long period of time characterized by high sea-level stand argues against it. 4. field analogue for hydrocarbon reservoirs the hareelv formation is an excellent field analogue for deeply buried hydrocarbon reservoirs of unusual shapes. thus the gryphon, alba, north/harding and other fields in the north sea have steep-sided, commonly mounded and convex-up geometries, and cores show abundant intrusive sands. these reservoir sands have been variously interpreted as turbidite fills of elongate erosional gullies, as convex-upward debrites or as remobilized and injected sands (dixon et al., 1995, and references therein). the latter explanation is receiving increasing support by improved seismic resolution data and retrieval of additional cores, and not least by the increasing attention paid to the relatively few field analogues such fig. 12 intruded massive sandstones formed by complete remobilisation and relatively long distance injection. the lowermost sheets show preserved consolidation lamination indicating relatively minor remobilisation. the subvertical dyke to the lower right is folded due to compaction of the mudstones. katedralen member, hareelv formation, southern jameson land. 78 geologia croatica 56/1 79surlyk and noe-nygaard: a giant sand injection complex: the upper jurassic hareelv formation... as the hareelv formation. the forth fields area is similar to the hareelv formation as regards the depositional model and post-depositional remobilization and injection. the interpretation of the gryphon/harding field involved the intrusion of sand along listric detachment faults (newman et al., 1993; dixon et al., 1995). such faults have not been observed in the hareelv formation and the margins of mounded sandstone bodies are non-faulted, except for much smaller conjugate faults, with throws of a few tens of centimetres commonly intersecting the top of sheet-like sandstones. remobilised sand bodies such as those of the hareelv formation are commonly sufficiently large to form economic hydrocarbon reservoirs. this is especially the case if several sand bodies are amalgamated (figs. 6, 9 and 11). they may be difficult to locate and interpret correctly because of their extremely irregular shape and occurrence in the deeper part of the basin. sandy intrusions may in addition play an important role in draining potential source rocks such as the hareelv formation. their presence in basinal mudstones improves connectivity, and they may form pathways for hydrocarbon migration into shallower, regular and more predictable sand bodies such as shelf-margin wedges. sandstone dykes and sills are commonly observed in cores and if correctly identified, suggest the presence of larger sand bodies in adjacent strata. vertical or steeply dipping intrusions may not be visible on seismic data, but their possible presence may be inferred from the irregular or mounded shapes of the reservoirs. 5. conclusions the upper oxfordian−volgian hareelv formation of jameson land, east greenland is probably the world’s largest sediment injection complex. it represents a common but somewhat overlooked class of a line-sourced, disorganized sandy density flow system derived from the collapsing fronts of shelf-margin wedges. the formation is 200−400 m thick and the sand occurs as large massive bodies tens of metres thick, hundreds of metres fig. 13 sandstone sills in mudstones below thick massive sandstone. katedralen member, hareelv formation, southern jameson land. fig. 14 cross-cutting sandstone dykes and sills. note ptygmatic compaction folding of the subvertical dyke. the upper sandstone is also a sill although it shows a strong similarity to a massive sandstone turbidite. katedralen member, hareelv formation, southern jameson land. 80 geologia croatica 56/1 81surlyk and noe-nygaard: a giant sand injection complex: the upper jurassic hareelv formation... wide and in some cases of kilometre length. the sandstone bodies are randomly distributed throughout the formation and consist of well-sorted fine-to-mediumgrained sand. the sand was deposited in steep-sided erosional slope gullies, and as more sheet-like bodies at the base-of-slope and in the basin. transport and deposition was from hyperconcentrated density flows passing down-slope into concentrated flows. the travel distance of the flows ranged from a few tens of metres to several tens of kilometres.. post-depositional remobilization, liquefaction and subsequent injection of sand into surrounding mudstones, strongly modified the density flow system and resulted in the formation of a complex of highly irregular, interconnected sand bodies, dykes and sills on all scales. remobilization took place repeatedly over more than 10 million years and ranged from almost syndepositional to rather deep burial, in scales ranging from a few centimetres to hundreds of metres. the formation was deposited during the main mesozoic rift phase in east greenland and remobilization was caused by earthquakes combined with the effects of overpressure induced by rapid burial, hydrocarbon migration and slope shear stress. the hareelv formation provides an excellent field analogue for complex subsurface jurassic and cenozoic hydrocarbon reservoirs in the north sea, the cretaceous of the norwegian shelf and many other areas. the excellent exposures allow study of sand body size, geometry and interconnectedness, and some of the amalgamated sandstone bodies are sufficiently large to be potential hydrocarbon reservoirs in their own right. the network of sandstone dykes and sills provides a highly effect drainage system for the hydrocarbons generated in the host source rock, and may act as a migration route to shallow, well organized shelf-margin sandstone wedges, which form a more obvious exploration target. fig. 15 model for the remobilisation, fluidization, liquefaction, intrusion and diapirism of sandstones in the hareelv formation, jameson land, east greenland. a and b show deposition of black mud under dysoxic to anoxic conditions and formation of a slope gully by retrogressive slumping (cf. figs. 3 and 4). the gully walls are commonly stepped with subvertical segments (cf. fig. 10). in c the gully is filled by a few sand flows as indicated by amalgamation surfaces outlined by stringers of mudstone chips and small clasts. in d the massive gully-fill sand is loaded into the still unconsolidated upper gully walls. e shows mounding of the sandbody and injection of sand dykes and sills after shallow burial (cf. figs. 9, 13 and 14). large mudstone clasts are ripped down from the overlying mudstone during remobilisation and intrusion. f shows a second remobilisation event under deeper burial. the lateral wing-like sills of the mounded top are deformed by differential compaction, early dykes are ptygmatically compaction folded (cf. figs. 12 and 13) and cross-cut by later intrusions and the consolidated lower part of the mudstone succession has developed regular orthogonal vertical and horizontal joints which are intruded by sand (cf. fig. 13). the indicated depth of burial is schematic and probably amounted to several tens of metres. 80 geologia croatica 56/1 81surlyk and noe-nygaard: a giant sand injection complex: the upper jurassic hareelv formation... acknowledgements we gratefully acknowledge support by norsk hydro a/s and the danish natural science research council. we are grateful to j. gjelberg and w. nemec for constructive discussion. we thank s. piasecki for useful information on palynology and company in the field, and c. hagen for artwork. 6. references anketell, j.m., cegla, j. & dzulynski, s. (1970): on the deformational structures in systems with reversed density gradients.– annales de la société géologique de pologne, 40, 3−30. bruhn, r. & surlyk, f. (in press): sand-grade density flow evolution on a shelf-edge–slope–basin floor complex in the upper jurassic olympen formation, east greenland.– petroleum geoscience. christiansen, f.g., dam, g., piasecki, s. & stemmerik, l. (1992): a review of upper palaeozoic and mesozoic source rocks from onshore east greenland.– in: spencer, a.m. (ed.): generation, accumulation and production of europe’s hydrocarbons. proceedings of the european association of petroleum geology, 2, 151−161. dixon, r.j., schofield, k., anderton, r. reynolds, a.d., alexander, r.w.s., williams, m.c. & davies, k.g. (1995): sandstone diapirism and clastic intrusion in the tertiary submarine fans of the bruce−beryl embayment, quadrant 9, ukcs.– in: hartley, a.j. & prosser, d.j. (eds.): characterization of deep marine clastic systems. geological society special publication, 94, 77−94. larsen, m. & surlyk, f. (2003): shelf edge delta and slope deposition in the upper callovian −middle oxfordian olympen formation, east greenland.– in: ineson, j.r. & surlyk, f. (eds.): the jurassic of denmark and greenland. geological survey of denmark and greenland bulletin, 1, 931–948. mulder, t. & alexander, j. (2001): the physical character of subaqueous sedimentary density flows and their deposits.– sedimentology, 48, 269−299. newman, m.st.j., reeder, m.l., woodruff, a.h.w. & hatton, i.r. (1993): the geology of the gryphon field.– in: parker, j. (ed.) petroleum geology of northwest europe: proceedings of the 4th conference. geological society, london, 123−135. nichols, r.j. (1995): the liquefaction and remobilisation of sandy sediments.– in: hartley, a.j. & prosser, d.j. (eds.) characterization of deep marine clastic systems. geological society special publication, 94, 63−76. surlyk, f. (1987): slope and deep shelf gully sandstones, upper jurassic, east greenland.– american association of petroleum geologists bulletin, 71, 464−475. surlyk, f. (2003): the jurassic of east greenland: a sedimentary record of thermal subsidence, onset and culmination of rifting.– in: ineson, j.r. & surlyk, f. (eds.) the jurassic of denmark and greenland. geological survey of denmark and greenland bulletin, 1, 659–722. surlyk, f. & noe-nygaard, n. (1991): sand bank and dune facies architecture of a wide intracratonic seaway: late jurassic − early cretaceous raukelv formation, jameson land, east greenland.– in: miall, a. d. & tyler, n. (eds.) the three-dimensional facies architecture of terrigenous clastic sediments and its implications for hydrocarbon discovery and recovery. sepm (society for sedimentary geology), concepts in sedimentology and paleontology, 3, 261−276. surlyk, f. & noe-nygaard, n. (2001): sand remobilisation and intrusion in the upper jurassic hareelv formation of east greenland.– bulletin of the geological society of denmark, 48, 169–188. manuscript received may 21, 2003. revised manuscript accepted june 20, 2003. 82 geologia croatica 56/1 mitchell.indd 1. introduction radiolitid rudists belonging to the genera bournonia fischer, biradiolites d’orbigny and thyrastylon chubb are abundant in the upper maastrichtian, titanosarcolites limestones (guinea corn formation and other formations) of jamaica. although there is a large literature on these jamaican forms (e.g., whitfield, 1897; trechmann, 1924; chubb, 1956, 1967, 1971), little information on their microstructure, or their detailed stratigraphy has been published. indeed, there have been few studies on the microstructure of rudists, although those there have been indicate that the microstructures have high taxonomic significance (e.g., amico, 1978; steuber, 1999). this paper presents morphology, microstructure and stratigraphy of some late cretaceous radiolitid rudists from jamaica simon f. mitchell a detailed study of the morphology, microstructure and stratigraphy of some of these radiolitid rudists, and a revision of some species. 2. geology in the central inlier of jamaica (fig. 1), the guinea corn formation (titanosarcolites-yielding limestones) forms the middle (marine) portion of the major transgressive–regressive kellits sythem (unconformity bounded stratigraphic unit) (mitchell, in press). these limestones are up to 200 m thick and contain subordinate mudrocks and sandstones (coates, 1965; mitchell, 1999, in press; mitchell & gunter, 2002). the thickest section through the guinea corn formation is exposed in the rio minho between grantham and frankfield and can be divided into rhythms up to about 10 m in thickness (mitchell, 1999, 2002). each rhythm consists of a lower clastic unit with diverse infaunal molluscs, a middle clastic/ carbonate unit with diverse corals and/or recumbent antillocaprinid rudists, and an upper part consisting of limestones with abundant radiolitid and antillocaprinid rudists. a bed lettering scheme, with the beds labelled from a to g (fig. 2) based on the relative proportions of limestone and clastics, was introduced by mitchell (1999). steuber et al. (2002) used sr-isotope geochronology to suggest a mid to late late maastrichtian age for the guinea corn formation of the central inlier, an age that agrees with the few well-determined ages based on other biostratigraphic groups (e.g., sharks – underwood & mitchell, 2000). 3. methodology for this study, rudists were systematically collected from two sections (fig. 1). extensive collections were made from the rio minho section between grantham and guinea corn (guinea corn in fig. 1) for which a detailed lithostratigraphy has been developed (mitchell, 1999; mitchell & gunter, 2002). additional material was collected from sections at slippery rock river, green river, logie green and pindars river (fig. 1). the section at pindars river (described by coates, 1965) is important because many of the rud geologia croatica 56/2 149–171 3 figs. 8 pls. zagreb 2003 key words: rudist bivalves, cretaceous, maastrichtian, taxonomy, jamaica. department of geography and geology, university of the west indies, mona, kingston, jamaica; e-mail: smitchell@cwjamaica.com abstract radiolitid rudists from the upper maastrichtian of jamaica include genera bournonia, biradiolites and thyrastylon. three species of bournonia are recognised, b. cancellata whitfield, b. barretti trechmann and b. thiadensi vermunt. b. cancellata evolves into b. barretti by the acquisition of costae on the anterior side. the species of bournonia are characterised by a distinctive cardinal apparatus, a thick inner shell layer, and an outer shell layer composed of cellular microstructure. two species of biradiolites are recognised – b. rudissimus trechmann has an outer layer composed of cellular microstructure with occasional bands of compact microstructure, particularly in the radial bands, and b. jamaicensis trechmann has a very well organised outer layer with an inner band of cellular microstructure and an outer band of compact microstructure. biradiolites and thyrastylon have a similar dentition, a thin inner layer and similar wall structures in the outer layer. thyrastylon is distinguished from biradiolites by the infolding of the radial bands in rv and by the presence of oscules in lv. the evolutionary change from bo. cancellata to bo. barretti, and the first appearance of bi. jamaicensis are probably useful biostratigraphic markers of the upper maastrichtian. 150 geologia croatica 56/2 151mitchell: morphology, microstructure and stratigraphy of some late cretaceous radiolitid rudists... ists are embedded in relatively soft mudstones allowing excavation of the cardinal apparatus. where particular species were common, populations were collected to aid with determining the range of variation within each rudist morphospecies. the terminology of microstructures follows amico (1978) and steuber (1999). longitudinal and transverse sections were cut through selected specimens, and the sections polished to show internal features. the polished surfaces were then etched with a 10% solution of hcl for 10 seconds, and allowed to dry. acetate peels were prepared from the etched surfaces. negative photographic prints were then developed from the acetate peels. all material, including acetate peels, is deposited in the geological museum at the university of the west indies (uwigm numbers). additional material studied is in the american museum of natural history (amnh) in new york, and the natural history museum (bmnh), london. 4. systematic palaeontology in the following account, long synonymy lists are not given. these are available in other publications (e.g, chubb, 1971; alencaster, 1971; steuber, 2002). here, only important synonyms are provided, and these are linked to the morphospecies concepts adopted/developed in this work. rudist morphospecies are here defined using populations of specimens, where possible, collected from the same level. this provides a more objective method of defining morphospecies that in the published literature where many species have been erected on one or two individuals. when the stratigraphic distribution of populations is examined, a better understanding of the time relationships of morphospecies becomes apparent. genera are defined on major morphological criteria, species on more subtle criteria. family radiolitidae d’orbigny, 1847 genus bournonia fischer, 1887 type species: sphaerulites bournoni des moulins, 1826. diagnosis: right valve (rv) conical with relatively thick inner aragonite layer. outer calcitic layer composed of funnel plates with rectangular cells, compact cell layers absent, no cortical layer observed. surface ornamented with strong costae and intervening furrows. radial bands represented by more prominent, or flattened costae. prominent, narrow anterior furrow (af) developed. left valve (lv) cap like, or a low cone. cardinal apparatus of type a (pl. 1). fig. 1 location of sections in the central inlier from which rudists have been collected. inset, map of jamaica showing inliers (additional material from the marchmont and maldon inliers). 150 geologia croatica 56/2 151mitchell: morphology, microstructure and stratigraphy of some late cretaceous radiolitid rudists... three maastrichtian species are recognised in jamaica: b. cancellata (whitfield), b. barretti trechmann and b. thiadensi vermunt. bournonia cancellata (whitfield, 1897) pls. 1, 2, 3d–f, 4a, c–d v. 1897 radiolites cancellatus: whitfield, p. 190, pl. 12, fig. 4, pl. 13, figs. 3–7. v. 1924 biradiolites subcancellatus: trechmann, p. 403, pl. 26, fig. 3. diagnosis: a species of bournonia in which the anterior side lacks costae. type specimens: the original material of whitfield (1897) is preserved in the amnh; it was collected from logie green in the central inlier. whitfield (1897) figured several specimens, his pl. 13, figs. 3–5 is here selected as lectotype. material: extremely abundant material from the a and b beds of guinea corn formation in the rio minho at grantham. also abundant specimens from the lowest limestone in the pindars river section. description: rv conical to cylindro-conical. ranging in height up to 14 cm and in diameter up to 7 cm. the external ornament consists of prominent costae which represent downfolds of the funnel plates, the intervening furrows corresponding to upfolds; both are obvious in transverse sections (pl. 1). the costae number between 7 and 10 and are limited in extent to the ventral, posterior and dorsal sides. the radial bands (posterior band – pb and ventral band – vb) are represented by broader costae with flat tops. the anterior side is devoid of longitudinal costae, and bears a single prominent anterior furrow. this furrow corresponds to a prominent downfold of the funnel plates. growth lines, corresponding to the outer edges of the funnel plates, are well-developed on all aspects; no cortical layer has been seen. fig. 2 simplified succession through the guinea corn formation in the rio minho between grantham and guinea corn showing bed divisions (after mitchell, 1999; mitchell & gunter, 2002). the boundary between the middle and upper c beds falls within a faulted gap in the section. 152 geologia croatica 56/2 153mitchell: morphology, microstructure and stratigraphy of some late cretaceous radiolitid rudists... transverse sections of the right valve indicate two well defined layers. the inner layer is up to 2 mm thick, and is represented by calcite spar. this is interpreted to be a replacement fabric after the original aragonitic inner layer. the outer layer is formed of funnel plates showing a quadrangular cellular microstructure; compact microstructural elements are lacking. longitudinal cross-sections show that the funnel plates are orientated upwards, with different degrees of upward extension producing the costae and furrows. conical tabulae, now represented by calcite menisci, fill the lower part of the body chamber (pl. 1f). lv ranges from flat to strongly arched. it has a similar microstructure to the rv, with a thick inner aragonite layer and an outer layer of quadrangular cellular microstructure (pl. 1e–f). the cardinal apparatus is of type a, and is seen in transverse and longitudinal sections, and also in a specimen excavated from the enclosing matrix (pls. 1a–d, 3d–f). the teeth of the left valve project deeply into the body cavity of the right valve (pl. 1e–f). they fit into sockets developed from the inner layer of the right valve (pl. 1a–d). the teeth are distinctly separated and connected by a strong yolk. the myophores extend from the teeth towards the ventral side, and are broadly parallel to one another (pl. 1a–d). posterior myophore (pm) is connected by a narrow neck, and anterior myophore (am) by a wide neck to the teeth (pl. 1). specimens occur in weakly conjoined bouquets of up to 10 individuals when found in growth position. however, most specimens occur as isolated, transported or toppled individuals in rudstone beds (mitchell, 2002). discussion: whitfield (1897) and chubb (1971) suggested that two anterior furrows may be developed in some specimens. this is considered erroneous here; one furrow represents af, whereas the other is a crack due to compaction. trechmann (1924) and chubb (1971) separated b. cancellata from b. subcancellata. these species differ in the relative height of their rvs, b. cancellata being tall and b. subcancellata short. the type specimen of b. subcancellata has the umbo of the rv broken off. considering the populations of b. cancellata collected from the guinea corn formation during this study, forms similar to b. subcancellata clearly represent extreme morphological variants of b. cancellata. b. subcancellata is therefore synonymised with b. cancellata here. bournonia barretti trechmann, 1924 pl. 3a–c v. 1924 bournonia barretti: trechmann, p. 405, pl. 26, figs. 2, 2a. diagnosis: a species bournonia in which the anterior side bears from several to many costae. type: trechmann (1924, pl. 26, figs. 2, 2a) figured a single specimen of bournonia barretti (bmnh l63227) from the great river valley near catadupa, st. james. this specimen is similar to forms occurring in the middle c beds in the central inlier, and is here selected as lectotype. material: many specimens collected from the guinea corn formation. forms transitional between b. cancellata and b. barretti are common in the lower c beds, whereas typical b. barretti has been collected from the middle c, upper c, d and g beds. it is generally rare. description: rv varies from cylindro-conical to cylindrical, and is up to 10 cm high and 7 cm in diameter. the dorsal, posterior and ventral sides bear strong costae with prominent furrows between. the anterior side in early examples (lower c beds of the central inlier) bears a few costae; in later forms (middle c to g beds of the central inlier) it bears numerous costae. up to 17 costae may be present in total around the entire shell. when the anterior surface is strongly cemented to a smooth hard substrate (such as a valve of antillocaprina or titanosarcolites), costae are not developed, and the specimen cannot be distinguished from b. cancellata. the radial bands are marked by two prominent costae. the anterior furrow is marked by a downfold of the funnel plates between two costae. lv cap like. specimens usually occur as isolated individuals in growth position. rarely specimens occur in conjoined bouquets numbering two or three individuals. discussion: b. cancellata and b. barretti appear to be part of an evolving lineage. b. cancellata occurs in rock-forming abundance in the limestones of the upper a and b beds. in the lower c beds forms with a few weak costae on the anterior side appear, and occur together with forms of typical b. cancellata morphology. these are here seen as transitional forms between b. cancellata and b. barretti. in the middle c beds, bournonia are rare, but those specimens collected have anterior sides with many costae and are typical of b. barretti; forms similar to b. cancellata are absent. b. barretti occurs sporadically through the upper c and d beds, and rarely in the g beds. alencaster (1971) included b. barretti in the synonomy of b. cardenasensis (böse, 1906). she recorded the latter species from vega del paso (locality 30) in the upper cretaceous of mexico. the associated rudist fauna from this locality included titanosarcolites macgillavryi alencaster, barrettia monilifera woodward, b. multilirata whitfield and b. gigas chubb. in jamaica, the b. gigas–b. multilirata assemblage is of late middle to early late campanian age (mitchell, in press), and b. cardenasensis is therefore older than the late maastrichtian b. barretti. b. barretti and b. cardenasensis are here considered as homeomorphs. 152 geologia croatica 56/2 153mitchell: morphology, microstructure and stratigraphy of some late cretaceous radiolitid rudists... bournonia thiadensi vermunt, 1937 pls. 3g–h, 4b 1937 bournonia thiadensi; vermunt, p. 271–272, pl. 36, figs. 4–5, text figs. 3e–g. v. 1967 bournonia tetrahedron: chubb, p. 28–29. v. 1971 bournonia tetrahedron: chubb, p. 195, pl. 40, figs. 11–12. diagnosis: a species of bournonia with four, five, or rarely six, prominent costae in adults. type: type specimens not seen. material: moderately rare in the upper middle c beds, d beds and f beds. a single specimen also from the base of the b beds. description: rv conical, up to 6 cm high and 7 cm in diameter. the exterior bears four very prominent costae, two broad costae representing the radial bands, and two acute costae at the ventral and dorsal margins of the flat anterior surface. a further costa may be developed, and sometimes two are seen on the dorsal side. the costae represent downfolds of the funnel plates, the furrows, upfolds. the anterior side is flat and bears the af, represented by a sharp downfold of the funnel plates. a single transverse section (pl. 4b) shows that the inner layer of the rv is about 2 mm thick, and the outer layer is composed solely of quadrangular cellular layers; compact layers are absent. the cardinal apparatus is not seen. the lv is cap like, and may bear prominent radial striations. b. thiadensis occurs as isolated individuals, often cemented to valves of other rudists. discussion: chubb’s (1967) species bournonia tetrahedron is a juvenile specimen of a bournonia with four costae. similar small specimens of bournonia cemented to hard substrates (usually rudist shells) are not uncommon in the upper part of the guinea corn formation. where such specimens have grown to maturity, they acquire the form of b. thiadensi. thus, b. tetrahedron is considered a juvenile of b. thiadensi here. genus biradiolites d’orbigny, 1850 type species: biradiolites canaliculatus d’orbigny, 1850. diagnosis: radiolitids with no ligamental infold, radial bands situated in furrows, cardinal apparatus of type b (pl. 5b), outer layer of rv formed of cellular and compact wall structures. biradiolites rudissimus trechmann, 1924 pls. 5b–c, 6c–d, 6f 1897 ?radiolites rudis; whitfield, 189, pl. 11, fig. 4. v. 1924 biradiolites rudissimus; trechmann, p. 402, pl. 26, figs. 4, 4a, 5. v. 1924 biradiolites minhoensis; trechmann, p. 402–403, pl. 26, figs. 1, 1a. 1956 biradiolites forbesi; chubb, p. 15–16, pl. 3, figs. 1–2. v. 1971 biradiolites riograndensis; chubb, p. 189, pl. 37, figs. 9–11. diagnosis: biradiolites with a broad, flat-topped vb and a strongly upfolded pb. other costae and furrows much reduced. type: trechmann (1924) figured two specimens of biradiolites rudissimus from the railway cutting at catadupa, st. james. trechmann’s (1924) pl. 26, fig. 5, is here selected as lectotype. material: numerous individuals from the titanosarcolites limestones of jamaica. description: a highly variable species of biradiolites. rv up to 15 cm in diameter and 11 cm high. the rv is conical and ranges from narrow, tall cones (radiolites rudisor biradiolites minhoensis-like forms) to broad, low cones. the margin of the rv is usually irregular, and may be devoid of costae and furrows other than for the radial bands. the radial bands are strongly marked and very distinctive. vb is characterised by a sunken, flat, square-topped upfold, and is broad. pb is narrower, convex and strongly upfolded. the apertural surface may bear plications and/or vascular impressions. transverse sections of rv show a thin inner layer (less than 0.5 mm thick), and an outer layer formed largely of quadrangular, cellular microstructure with occasional irregular compact layers (pl. 5b–c). compact layers are often best developed adjacent to the radial bands. the cardinal apparatus is of type b (pl. 5b). the teeth are relatively close together and fit into sockets in the rv. they are connected by a yoke that forms a small accessory cavity between the cardinal apparatus and the inner layer of the rv. the myophores form two arcs extending towards the ventral side (pl. 5b). lv cap-like, with a raised central portion (pl. 6c), and a flat brim that extends across the apertural surface. this brim is usually broken away, although vestigaes are sometimes preserved (e.g., at the top of pl. 6c). b. rudissimus occurs as isolated individuals, or in small conjoined bouquets numbering up to three individuals. discussion: a great deal of confusion surrounds the relationship between radiolites rudis whitfield and 154 geologia croatica 56/2 155mitchell: morphology, microstructure and stratigraphy of some late cretaceous radiolitid rudists... biradiolites rudissimus trechmann. the type and only specimen of r. rudis is in amnh, and is embedded in a hard limestone matrix. consequently, the form of the radial bands cannot be determined. the general morphology of the rv resembles narrow specimens of b. rudissimus, but in the absence of details of the radial bands the specimen must be regarded as indeterminate. r. rudis is therefore questionably placed in the synonymy list of b. rudissimus here. biradiolites minhoensis trechmann has a shape typical of conical specimens of b. rudissimus, but with rather smooth radial bands. similar specimens with smooth radial bands do occur in large populations of b. rudissimus (e.g., a population taken from rhythm d1 in the central inlier), and since b. rudissimus has page preference, b. minhoensis is placed in synonymy here. in describing biradiolites forbesi and b. rudissimus, chubb (1971, p. 188) stated that “[it] appears there is little… to differentiate between the two species”, and b. forbesi is placed in synonymy here. b. riograndensis chubb also has similar radial bands to b. rudissimus, and falls within the range of collected populations. biradiolites jamaicaensis trechmann, 1924 pls. 5a, 5d–e, 6a–b, 6e v. 1924 biradiolites jamaicensis; trechmann, p. 404, pl. 24, figs. 5, 5a, 6, 6a, 7. v. 1967 biradiolites robinsoni; chubb, p. 27. v. 1971 biradiolites robinsoni; chubb, p. 187, pl. 36, figs. 1–3. diagnosis: biradiolites with strong stellate transverse sections, well-organised thick cellular and compact layers, and a double costa in the interband. type: trechmann (1924) figured three specimens of b. jamaicensis. his pl. 24, figs. 5, 5a is the most typical, and is here designated as lectotype. material: abundant material from the guinea corn formation and elsewhere in the titanosarcolites limestones of jamaica. description: rv cylindrical, straight, twisted or gently arched. diameter up to 4 cm, length up to 25 cm. rv bears between 7 and 12 strong angular costae, including the two costae in the interband. minor, longitudinal ridges may be developed on some costae. the cross section ranges from triangular to square to broadly rounded. pb and vb are marked by flat bands on either side of the prominent double costae of the interband (pls 5a, 6a–b, 6e). the surface of rv is smooth. transverse sections indicate a very well structured wall of the rv. the inner layer is very thin (less than 0.5 mm). the outer layer is divided into an inner portion with quadrangular cellular layers and an outer portion of compact layers (pl. 5a, 5e). the compact layers correspond to the strongly upturned margin of the funnel plates (pl. 5d). cardinal apparatus similar to b. rudissimus. lv with a central raised portion, and a brim extending across the apertural face. the thin brim is often broken away. occurs as ramifying masses and well-defined bouquets of up to 100 or more individuals (mitchell, 2002). discussion: chubb (1967) erected b. robinsoni for a short, curved form. the type specimen is missing (edward robinson, pers. comm., 2000), although a cast of it is in the bmnh. this specimen shows the typical radial bands of b. jamaicensis, and b. robinsoni is placed in synonymy here. genus thyrastylon chubb, 1956 type species: radiolites adhaerens whitfield, 1897. diagnosis: a radiolitid with no ligamental infold, quadrangular cellular and compact layers in the outer layer of rv, type b cardinal apparatus, radial bands partially infolded into the shell layer of the rv, and oscules developed in the lv. thyrastylon adhaerens (whitfield, 1897) pls. 7, 8 v. 1897 radiolites adhaerens; whitfield, p. 188– 189, pl. 10, fig. 1, pl. 12, fig. 1. diagnosis: as for genus (but see discussion). type: whitfield (1897) figured several specimens of radiolites adhaerens. no lectotype is currently selected, pending revision of trechamnn’s (1924) and chubb’s (1956, 1971) species concepts. material: abundant material from the titanosarcolites limestones of jamaica. description: rv cylindrical to conical, up to 10 cm long and 7 cm in diameter. margin broadly rounded and irregular, with radial bands marked by wide or narrow furrows. aperture with radial plications and/or vascular impressions. transverse cross sections of the rv show a thin inner layer (less than 0.5 mm) and an outer layer formed mainly of quadrangular cellular microstructure with occasional bands of compact microstructure (pl. 7c). compact shell layers are particularly developed around the infolded radial bands (pl. 7d). longitudinal sections show the upward projecting funnel plates, with occasional layers of compact microstructure, which is also concentrated adjacent to the infolded radial bands (pl. 8a–b). the cardinal apparatus is type b as in b. rudissimus (see chubb, 1971). 154 geologia croatica 56/2 155mitchell: morphology, microstructure and stratigraphy of some late cretaceous radiolitid rudists... the lv is cap like, with a central raised/domed section and a wide thin brim that extends across the apertural face. the lv has two oscules developed above the radial bands (chubb, 1956, 1971). specimens occur as weakly to strongly attached elevators or clingers. sometimes in bouquets numbering up to 20 or more individuals. discussion: trechmann (1924) erected two further species, biradiolites coryi and biradiolites semiannulosus, that chubb (1956) placed in thyrastylon. the distinction between these ‘species’ is remarkably difficult in many of the collected specimens. a full revision of the genus using populations is needed to sort out the species concepts in this genus. many of the features of thyrastylon resemble those of b. rudissimus. the genus differs in the infolding of the radial bands and the development of oscules in the lv. 5. stratigraphy the distribution of the maastrichtian rudists discussed in this paper, together with similar forms from the santonian and campanian of jamaica is shown in fig. 3. this demonstrates that bo. cancellata-like, bo. thiadensi-like and bi. rudissimus-like forms occur over extended ranges. in continuous sections, in would probably be difficult to separate these ‘species’, which undoubtedly represent lineages. the evolutionary change from bo. cancellata to bo. barretti, and the first appearance of bi. jamaicensis are probably useful biostratigraphic markers of the upper maastrichtian. acknowledgements many thanks to gavin c. gunter who collected some of the specimens from western jamaica illustrated in this paper. many thanks to shakira khan for printing the negative prints. thanks to thomas steuber and gloria alencaster for help with obtaining literature, and to stefan götz and tvrtko korbar for valuable comments on the original manuscript. 6. references alencaster, g. (1971): rudistas del cretacico superior de chiapas [upper cretaceous rudists from chiapas – in spanish].– paleontologia mexicana, 34, 1–91. amico, s. (1978): recherches sur la structure du test des radiolitidae [study of the shell structure of radiolitidae – in french].– traveaux du laboratoire de géologie historique et de paléontologie, 8, 1–131. fig. 3 stratigraphy of radiolitid rudists from the upper cretaceous of jamaica. jm = jerusalem mountain occurrences, a–g = beds in guinea corn formation; the gap between jm and a–g is not known at outcrop. 156 geologia croatica 56/2 157 böse, e. (1906): la fauna de moluscos del senoniano de cárdenas, s.l.p. [the mollusc fauna of the senonian of cardenas, s.l.p. – in spanish].– boletín del instituto geológico de méxico, 24, 1–92. chubb, l.j. (1956): thyrastylon, a new rudists genus from the upper cretaceous of guatemala, the antilles, and persia, with a discussion of the function of rudists oscules and pillars.– palaeontographica americana, 4/27, 33–49. chubb, l.j. (1967): new rudist species from the cretaceous rocks of jamaica.– journal of the geological society of jamaica, 9, 24–31. chubb, l.j. (1971): rudists of jamaica.– palaeontographica americana, 7, 161–257. coates, a.g. (1965): a new section in the maastrichtian guinea corn formation near crawle river, clarendon.– journal of the geological society of jamaica (geonotes), 7, 28–33. fischer, p. (1887): manuel de conchyliologie et de paléontologie conchyliogique ou histoire naturelle des mollusques vivants et fossils [manual of shell and shell paleontology and natural history of recent and fossil molluscs – in french].– f. savy, paris, 1369 p. mitchell, s.f. (1999): stratigraphy of the guinea corn formation (upper cretaceous) at its type locality between guinea corn and grantham (northern clarendon, jamaica).– journal of the geological society of jamaica, 33, 1–12. mitchell, s.f. (2002): palaeoecology of corals and rudists in mixed volcaniclastic–carbonate small-scale rhythms (upper cretaceous, jamaica).– palaeogeography, palaeoclimatology, palaeoecology, 186, 237–259. mitchell, s.f. (in press): sedimentary and tectonic evolution of central jamaica.– in: bartolini, c., burke, k., buffler, r., blickwede, j. & burkart, b. (eds.): mexico and the caribbean region: plate tectonics, basin formation and hydrocarbon habitats.– american association of petroleum geologists memoir. mitchell, s.f. & gunter, g.c. (2002): biostratigraphy and taxonomy of the rudist chiapasella in the titanosarcolites limestones (maastrichtian) of jamaica.– cretaceous research, 23, 473–487. des moulins, c. (1826): essai sur les sphérulites qui existent dans les collections de mm. f. jouannet, member de l’académie royale des sciences, belle lettres et arts de bordeaux, et charles des moulins; et considerations sur la familie à laquelle ces fossils appartiennent [essay on the dherulites in the collection of mmf jouannet, member of the royal academy of sciences, beautiful letters and arts of bordeaux, and charles des moulins and consideration on the families to which these fossils belong – in french].– bulletin d’histoire naturelle de la société linnéenne de bordeaux, 1, 148–303. plate 1 bournonia cf. cancellata (whitfield), forms with a few weak costae on anterior side, lower c beds, guinea corn a – uwigm.rud.3003.3; b–e – uwigm.rud.2003.171–174, respectively; f – uwigm.rud.2003.2. a–d transverse sections cut at various levels and angles through the cardinal apparatus. e–f longitudinal sections. camera lucida drawings, outer layer structure simplified. black, aragonitic inner layer of left valve; dark grey, aragonitic inner layer of right valve; light greys calcitic outer layers of left and right valves; dotted, epifornal corals. pm, posterior myophore; am, anterior myophore; pb, posterior band; vb, ventral band; af, anterior furrow. note intense boring (entobia isp.) in upper part of aragonitic inner layer of left valve in f. 156 geologia croatica 56/2 157mitchell plate 1 i' b af 158 geologia croatica 56/2 159 d’orbigny, a. (1847): sur les brachiopods ou palliobranchs [on the brachiopods and pallialbranchs – in french].– comptes rendus hebdomadaires des séances de l’académie des sciences, 25, 266–269. d’orbigny, a. (1850): paléontologie francaise, terrains crétacés. vol. 4, brachiopodes [paleontology of france, cretaceous rocks. vol. 4, brachiopods – in french].– bertrand, paris, 105–328. steuber, t. (1999): cretaceous rudists of boeotia, central greece.– special papers in palaeontology, 61, 229 p. steuber, t. (2002): depository item 2002022, list of occurrences of rudist bivalves (hippuritoidea) in the americas. plate tectonic control on the evolution of cretaceous platform-carbonate production.– geology, 30, 259, 71 p. steuber, t., mitchell, s.f., buhl, d., gunter, g. & kasper, h.u. (2002): catastrophic extinction of caribbean rudist bivalves at the cretaceous–tertiary boundary.– geology, 30, 999–1002. trechmann, c.t. (1924): the cretaceous limestones of jamaica and their mollusca.– geological magazine, 61, 25–410. underwood, c.j. & mitchell, s.f. (2000): serratolamna serrata (agassiz) (pisces, neoselachii) from the maastrichtian (late cretaceous) of jamaica.– caribbean journal of earth science, 34, 25–30. vermunt, l.w.j. (1937): cretaceous rudistids of piñar del rio, cuba.– journal of paleontology, 11, 261–275. whitfield, r.p. (1897): descriptions of species of rudistae from the cretaceous rocks of jamaica, w. i., collected and presented by mr. f. c. nichols.– bulletins of the american museum of natural history, 9, 185–196. manuscript received march 04, 2003. revised manuscript accepted november 04, 2003. plate 2 a–c three views of conjoined specimens of bournonia cancellata (whitfield), bed 15 upper, upper a beds, guinea corn, uwigm.rud.2002.89. anterior furrow (af) obvious in b. 158 geologia croatica 56/2 159mitchell plate 2 c b 1cm 160 geologia croatica 56/2 161 plate 3 a–c bournonia barretti trechmann, lower c beds (upper part), slippery rock river, uwigm.rud. 2002.90. d–f cardinal apparatus of bo. cancellata, lowermost limestone, pindars river section, uwigm.rud.2003.1. g–h bo. thiadensi vermunt, f beds, green river, uwigm.rud.2002.73. vb, ventral band; pb, posterior band. 160 geologia croatica 56/2 161mitchell plate 3 1 em vb 162 geologia croatica 56/2 163 plate 4 a, c transverse section of bournonia cf. cancellata (same as pl. 1b); b transverse section of bo. thiadensi, marchmont inlier, uwigm.58ca34; d longitudinal section of bo. cf. cancellata (same as pl. 1e). negative prints of acetate peels. scale bar = 1 cm; a and b show the inner aragonitic layer, and the outer calcitic layer composed of quadrangular cell structure; c, detail showing quadrangular cell structure in outer shell layer; d, showing the very thick aragonitic inner layers of the left and right valves, and the massive aragonite of the cardinal structure; note the closely spaced funnel plates in the outer layer. aragonite of inner layer replaced by calcite. 162 geologia croatica 56/2 163mitchell plate 4 164 geologia croatica 56/2 165 plate 5 a, e transverse section of biradiolites jamaicensis trechmann, uppermost limestone, pindars river, uwigm.rud.2001.114; note the well developed compact (co) and cellular (ce) structure of the outer shell layer. b, c transverse section of bi. rudissimus trechmann, rhythm d1, guinea corn, uwigm.rud.2001.114; b shows the cardinal structure, and alternation of compact (co) and cellular (ce) microstructure in the outer shell layer; c, detail showing compact (co) shell structure in pb. d longitudinal section of bi. jamaicensis, upper part lower c beds, guinea corn, uwigm.rud.2002.96; note that the compact (co) shell structure corresponds to the strongly vertical upturned part of the funnel plates. scale bar = 1 cm. pb, posterior band; vb, ventral band. negative prints of acetate peels. 164 geologia croatica 56/2 165mitchell plate 5 166 geologia croatica 56/2 167 plate 6 a, b biradiolites jamaicensis trechmann, middle c beds, guinea corn, uwigm.rud.2001.50; c–d bi. rudissimus trechmann, marchmont inlier, uwigm.rg.2001.109.mm15 (collected by gavin gunter and sfm); e bi. jamaicensis, logie green, uwigm.rud.2001.147; f bi. rudissimus, rhythm d1, guinea corn, uwigm.rud.2001.117, split showing body cavity. pb, posterior band; vb, ventral band. 166 geologia croatica 56/2 167mitchell plate 6 f 1 em 168 geologia croatica 56/2 169 plate 7 a–b thyrastylon adhaerens (whitfield); a, lower c beds, guinea corn, uwigm.rud.2002,143; b, uwigm.rg.2001.96.mm16, marchmont inlier (collected by gavin gunter); c–d t. adhaerens [form approaching t. coryi (trechmann)], middle c beds, guinea corn, uwigm.rud. 2002.104. pb, posterior band; vb, ventral band. 168 geologia croatica 56/2 169mitchell plate 7 b 1 em 170 geologia croatica 56/2 171 plate 8 a, b longitudinal section of thyrastylon adhaerens (whitfield) cut through a radial band showing compact (co) and cellular (ce) microstructure, d beds, guinea corn, uwigm.rud.2003.175; c, d detail of c: transverse section showing infolded radial bands showing compact (co) and cellular (ce) microstructure, middle c beds, guinea corn, uwigm.rud.2002.91. scale bar = 1 cm. negative prints of acetate peels. 170 geologia croatica 56/2 171mitchell plate 8 d 172 geologia croatica 56/2 marton.indd 107 �geologia croaticageologia croatica ab stra ct for the purpose of this work samples for palaeomagnetic analysis were taken from upper cenomanian and lower senonian shallow water limestones, as well as from senonian pelagic limestones from both ist and the surrounding islands. this area belongs to imbricated adria, which is characterized by gently folded and faulted strata with a dinaridic (nw–se) trend. an exception is premuda island where the beds are strongly folded and are subvertical. a total of 96 samples were drilled from 10 localities distributed between eight islands. the samples were then subjected to standard palaeomagnetic laboratory analysis and statistical evaluation. eventually, six localities yielded statistically well-defi ned palaeomagnetic directions, which were shown pre date the folding in age. the overall mean palaeomagnetic direction obtained for the study area, characterizing the cenomanian–early senonian time period had a declination of 334°, inclination=+46°, with statistical parameters k=188, a95=4.9°, defi ning a palaeomagnetic pole at l(n)=63°, f(e)=254°, dp=4.0°, dm=6.2°. this was compared with palaeomagnetic directions obtained for rocks of similar ages from stable istria and the kvarner islands. as the three palaeomagnetic directions are statistically identical, we conclude that there was no signifi cant relative movement between the three areas after the early senonian. the palaeomagnetic declination for the study area, which characterizes the post-early senonian rotation of the adriatic microplate, is the same as the declination for the pannonian–pontian age group from the south pannonian basin. as the palaeomagnetic signals in both cases are primary, the results of the present paper not only support the conclusion that the rotating adriatic microplate triggered rotations in the south pannonian basin, but also suggest that the adriatic platform did not change its orientation between the late cretaceous and the early pontian. keywords: imbricated adria, palaeomagnetism, late cretaceous new palaeomagnetic results from imbricated adria: ist island and related areas � emő márton1 and alan moro2 1 palaeomagnetic laboratory, eötvös loránd geophysical institute of hungary, columbus 17–23, 1145 budapest, hungary; (paleo@elgi.hu) 2 department of geology, faculty of science, university of zagreb, horvatovac 102a, 10000 zagreb, croatia; (amoro@geol.pmf.hr) doi: 10.4154/gc.2009.09 geologia croatica 62/2 107–114 10 figs. 2 tabs. zagreb 2009 1. introduction tectonically oriented palaeomagnetic studies in croatian territory started in the 1980s. the fi rst results were published from cretaceous rocks of stable istria (area 1 in fig.1, márton & veljović, 1983), followed by a number of papers concerning imbricated istria and the kvarner islands (márton & veljović, 1987, fig. 1, areas 2–3), kvarner islands (márton et al., 1990) and dugi otok (fig 1., area 4) and vis (fig. 1, area 5) islands (márton & milicević, 1994). these results were obtained on platform carbonates which contain extremely small amounts of magnetic minerals, therefore, their bulk susceptibilities are invariably diamagnetic and their natural remanent magnetizations are of very low intensities. consequently, platform carbonate samples sometimes fail to yield palaeomagnetic signals. sometimes the palaeomagnetic directions have poor statistical parameters, as has been shown in pioneering work on the adriatic platform carbonates. nevertheless, there are quite a number of geologia croatica geologia croatica 62/2 108 fi gu re 1: sketch map of croatia with main thrust fronts (after tari, 2002 and mikes et al., 2008). the areas of previous palaeomagnetic investigations are shaded. 1 – stable istria (márton & veljović, 1983, márton et al., 2003, 2008), 2 – imbricated istria and kvarner islands (márton & veljović, 1987), 3 – kvarner islands (márton et al., 1990), 4,5 – dugi otok and vis (márton & milicević, 1994), 6,7,8 – medvednica mt., ivancica mt., pozeska mt, krndija mt. and papuk mt. (márton et al., 1999, 2002, 2005), 9 – krsko and karlovac basin (márton et al., 2006). fi gu re 2: simplifi ed geological map (after mamuzić, 1970 and mamuzić et al. 1970), with the palaeomagnetic sampling localities 1–10. geologia croaticaemő márton and alan moro: new palaeomagnetic results from imbricated adria: ist island and related areas 109 previously published palaeomagnetic directions which have passed the present strict criteria developed to ensure goodquality data (see. márton et al., 2008) intensive and systematic palaeomagnetic investigation started in the early 1990s in two areas. the study of adriatic platform carbonates (fig. 1, area 1) resulted in the defi nition of an apparent polar wander path (apw) for the tithonian through mid-late eocene periods of time for stable istria (márton et al., 2003, 2008). in the south pannonian basin (fig. 1, area 6–9), the targets were tertiary rocks, which show ed counter-clockwise (ccw) rotations of post-early pontian age. these rotations were interpreted as having been triggered by the ccw rotating adriatic microplate (márton et al., 1999, 2002, 2005). palaeomagnetic observations in the area between the southern pannonian basin and stable istria are poorly distributed. as these observations are mostly from the 1980s, observations since 2006 have been concentrated on the tectonically more complicated external dinarides. the present paper is an initial step in this vein, as it deals with the palaeomagnetism of an area belonging to the imbricated margin of stable adria. 2. geological background ist island and its surrounding islands (fig. 2), which are palaeogeographically part of adriatic carbonate platform (vlaho vić et al., 2005), belong to a geotectonic unit, known variously as adriaticum (herak, 1991), or imbricated adria (tari, 2002) depending on the geotectonic interpretation. the region is characterized by gently folded and faulted creta ceous and palaeogene strata (which transgressively overlie the cretaceous, mamužić & sokač, 1967; moro & jelaska, 1994; ćosović et al., 1994), with a dinaridic (nw–se) trend. an exception is premuda island where the beds are strongly folded. our study area is situated (fig. 1) practically halfway between stable adria and the western thrust belt (tari, 2002) or dinaricum (herak, 1991). in the study area, upper cretaceous, shallow water, peritidal limestones prevail (vlahović et al., 2005), which range in age from the cenomanian–lower senonian (mamužić & sokač, 1967; moro & jelaska, 1994). early turonian pelagic sediments deposited on a drowned platform are the exception (gušić & jelaska, 1990; moro et al., 2002; vlahović et al., 2005). during the mid turonian, shallow-water sedimentation was re-established on olib island, while at silba, premuda and ist islands pelagic sedimentation continued until the senonian (kapović & bauer, 1970; moro, 1993). on most islands, strata are subhorizontal (fig. 3) or sw and ne dipping with angles up 25° (fig. 2). an exception is premuda island with subvertical beds (fig. 4). shallow water peritidal limestones are characterized by the vertical alteration of intertidal laminites and subtidal limestones. subtidal limestones appear in two varieties: foraminiferal wackestone-packstones, rarely grainstones and rudist or chondrodonta fl oatstones. depositional environments of these limestones were the shallow and protected parts of the carbonate platform. the pelagic limestones are characterized by the massive pelagic limestones with lenses of resedimented shallow water material, which could be in alteration with laminated pelagic limestones. the depositional environment could be deterrmined as a transition between the shallow platform and deeper basin (kapović & bauer, 1970). 3. palaeomagnetic sampling for the purpose of this work, samples were taken from upper cenomanian and lower senonian shallow water limestones, as well as from senonian pelagic limestones for palaeomagnetic studies. the strata sampled were invariably light grey or white in colour. samples were drilled and oriented in the fi eld with a magnetic compass. beds with shallow dips were preferred, though at one locality (premuda) subvertical strata were sampled (fig. 4). tilts of the sampled strata were recorded and used later, during the evaluation of the data as correction parameters for restoring the horizontal position of the beds. fi gu re 3: subhorizontal beds at ist island (locality 5) with palaeomagnetic boreholes (arrow). geologia croatica geologia croatica 62/2 110 the sampling localities are distributed over several islands, partly because of the character of the region, partly because several outcrops on the larger islands were heavily karstifi ed (e.g. olib, silba). among the sampling localities there are abandoned quarries (localities 5, 6 and 8 on fig. 2) as well as natural coastal outcrops. eventually, 96 samples were collected from 10 geographically distributed localities (fig. 2 and table 1). 4. laboratory processing and results the samples were cut into standard-size specimens and the natural remanent magnetization (nrm) as well as the magnetic susceptibility of each specimen was measured in the laboratory. the instruments used were jr4 and jr5a magnetometers and a kly-2 kappabridge. in case of magnetic intensities exceeding 12x10–5 a/m, one of the specimens (if the core was long enough to provide sister specimens) were demagnetized stepwise using the alternating fi eld (af) meth od, the other using the thermal method. at lower nrm intensities, both specimens were demagnetized with af, (as years of experience with extremely weakly magnetic platform carbonates from istria showed that the thermal method was not practicable in such cases, márton et al., 2003, 2008), and the better defi ned demagnetization curve of the sister specimens was used for evaluation. the fi rst step of the evaluation was component analysis (kirschvink, 1980) of the table 1: locality mean palaeomagnetic directions with statistical parameters for ist island and related areas. key: n/no: number used/collected samples (the samples are independently oriented cores), d, i, dc, ic: declination, inclination before and after tilt correction, k and a95: statistical parameters (fisher, 1953). locality lat. long. n/no do io k α95 o dc o ic o k α95 o dip 1 ist, port hr 953-961 44°16’44.8” 14°45’25.5” 7/9 340 +52 21 13 329 +42 42 9 314/10 252/25 2 silba, nozdre bay hr 962-971 44°21’19.7” 14°43’24.3” 6/10 328 +40 55 9 334 +48 55 9 110/10 3 olib, sv. nikola port hr 972-80 44°21’19.9” 14°46’23.1” 0/9 too weak 4 škarda hr 981-86 44°16’23.7” 14°42’58.6” 0/6 too weak 5 ist, abandoned quarry hr 987-995 44°15’22.9” 14°45’54.6” 9/9 336 +49 108 5 338 +48 108 5 42/2 6 tramerka hr 996-904 44°13’21.9” 14°46’08.0” 6/9 337 +51 230 4 325 +45 230 4 271/12 7 premuda, široka bay hr 1137-154 44°19’05.3” 14°37’52.5” 5/18 3 –20 73 9 347 +45 73 9 219/82 8 funestrala hr 1155-166 44°15’07.9” 14°44’39.0” 8/12 330 +44 98 6 332 +48 98 6 125/5 9 molat, vodomarka bay, hr 1167-172 44°14’17.1” 14°15’21.0” 6/6 great circle distribution 10 ist, kosirača bay hr 1173-80 44°17’5.5” 14°45’21.5” 0/8 too weak fi gu re 4: subvertical beds at premuda island (locality 7) with palaeomagnetic boreholes (arrow). geologia croaticaemő márton and alan moro: new palaeomagnetic results from imbricated adria: ist island and related areas 111 demagnetization plots for linear segments. as figs. 5 and 6 show, the demagnetization curves sometimes exhibit a single component, going practically to the origin (fig. 5, specimen hr 991). however, the nrm is often composite, (despite the fact that the only magnetic mineral in the collected samples is magnetite, as fig. 7 suggests), especially that of samples with stronger palaeomagnetic signals, (the demagnetization curves in figs. 5 and 6, except hr 991). in all cases, the components ending at or close to the origin were chosen to represent the characteristic remanence (chrm) of a sample, and the locality mean palaeomagnetic directions were calculated from one direction per independently oriented sample. as table 1 documents, all locality mean palaeomagnetic directions have good statistical parameters and depart signifi cantly from the present north. thus, they can be considered as well-defi ned palaeomagnetic signals and as synfi gu re 5: typical demagnetization curves. af demagnetized specimens from locality 5 showing the varied nrm intensities and the behaviour of the nrms on demagnetization. zijderveld diagrams plus normalized nrm intensity versus af fi eld. key to the zijderveld diagrams: fi lled circles are the projection of the palaeomagnetic vector onto the horizontal plane; open circles, projections onto the vertical plane. fi gu re 6: typical demagnetization curves. af demagnetized specimens from locality 8 (hr 1156 and hr 1162), documenting that after the removal of the overprint component, which is of diff erent directions for the two specimens, the chrms are of similar directions. an af demagnetized specimen from locality 6 (hr 996) and a thermally demagnetized one from locality 7 (hr 1144). key is as for fig.5, but for the last sample the smaller diagram is an intensity (circles) / susceptibility (dots) versus temperature diagram. geologia croatica geologia croatica 62/2 112 folding fisher analysis shows, they predate the age of folding (table 2 and fig. 8). the chrms of one locality (vodo marka) were not suited for evaluation by the fisher method since they exhibit a great circle distribution. this great circle (in the tectonic system) closely passes by the group of tiltcorrected palaeomagnetic directions of the other localities, suggesting that the component of the pre-folding age is similar to the ancient magnetic directions of other localities (fig. 9). however, the statistical parameters for the overall palaeomagnetic direction are better without the locality of vodomarka. therefore the cenomanian–early senonian of the study area is based on six geographically distributed localities (table 2). 5. discussion and conclusions the overall-mean palaeomagnetic direction predating the age of folding for the study area characterizes the cenomanian–lower senonian time period. palaeomagnetic direcfi gu re 8: locality mean palaeomagnetic directions with confi dence circles before (left stereogram), and after (right stereogram), tilt corrections. the middle diagram shows the result of the syn-tilting fisher analysis. the best grouping of the locality mean palaeomagnetic directions is achieved close to 100% unfolding and the peak is extremely high, meaning that the test is signifi cant. table 2: oveall mean palaeomagnetic directions for cenomanian–early senonian localities, before and after tilt corrections with statistical parameters and palaeomagnetic poles calculated from the tilt-corrected directions for ist island and related areas, for stable istria (the fi rst version comprises the cenomanian and early senonian localities, the second also turonian localities) and for the kvarner islands. n d° i° k α95° dc° ic° k α95° l(n) f(e) δp δm study area cenomanian+lower senonian 6 340 38 8 25.4 334 46 188 4.9 63 254 4.0 6.2 stable istria cenomanian+coniacian 8 323 45 44 8.5 334 51 65 7.5 66 259 6.9 10.1 cenomanian–coniacian 12 325 44 54 5.9 334 50 60 5.7 65 257 5.1 7.6 kvarner islands cenomanian–turonian 6 309 45 33 11.9 327 47 27 13.1 59 263 10.9 16.9 fi gu re 7: magnetic mineralogy experiments. the acquisition behaviour of the isothermal remanent magnetization indicates magnetite as the only magnetic mineral in the samples. geologia croaticaemő márton and alan moro: new palaeomagnetic results from imbricated adria: ist island and related areas 113 tions published for rocks of similar ages are known from stable istria and the kvarner islands, the fi rst representing the hard core of the adriatic microplate (márton et al., 2003, 2008), the second the nw part of imbricated adria. before such a comparison it has to be emphasized that the results for the cenomanian–early senonian time period of the present study are superior to those previously obtained from stable istria and the kvarner islands, in the sense that the age of the magnetization is better constrained. this is because the syn-tilting fisher analysis yields the best statistics close to 100 % unfolding for the study area (table 2) and the statistical improvement is signifi cant (fig. 8), while in the previously published cases the age of the magnetizations are not so tightly connected to the age of the sampled rocks. nevertheless, the overall-mean palaeomagnetic directions for the cenomanian–early senonian time period for the three above mentioned areas (fig. 2) have statistically identical overall palaeomagnetic directions (fig. 10). this situation has an important tectonic implication, which is the lack of large scale relative movement between the respective areas, after the early senonian. in other words, stable istria and at least the nw part of its imbricated margin can be treated as a rigid block in the course of plate tectonic displacements from the late cretaceous onwards. the declination of the overall-mean palaeomagnetic direction obtained for the study area is 334°. interestingly, the palaeomagnetic declination for a combined pannonian–pontian group of localities for the southern pannonian basin is also 334° (márton et al., 2002). as the palaeomagnetic signals in both cases are primary, the results of the present paper not only support the conclusion that the rotating adriatic microplate triggered rotations in the south pannonian basin (márton et al., 2002, márton, 2006), but also suggest that the adriatic platform did not change its orientation between the late cretaceous and the early pontian. acknowledgement the authors thank vlasta tari, robert scholger and bruno tom lje nović for their careful revision of the manuscript, gábor imre and robert koscal for technical assistance, as well as mr. slavijan deroko for boat transportation. this work was fi nancially supported by a croatian–hungarian intergovernmental scientifi c and technological project no. cro-06/2006, by a hungarian scientifi c research foun dation otka project no. k049616 and by a croatian ministry of science education and sport project no. 119-1191152-1167. references ćosović, v., balončić, d., koić, m., marjanac, t., moro, a., gušić, i. & jelaska, v. (1994): paleontological evidence of palaeogene transgression on adriatic carbonate platform.– géol. méditerran., 21/3–4, 49–53. fisher, r.a. (1953): dispersion on a sphere.– proceedings of the royal society london, 217, 295–305. gušić, i. & jelaska, v. (1990): stratigrafi ja gornjokrednih naslaga otoka brača u okviru geodinamske evolucije jadranske karbonatne platforme [upper cretaceous stratigraphy of the island of brač within the geodynamic evolution of the adriatic carbonate platform – in croatian].– djela jugoslavenske akademije znanosti i umjetnosti, zagreb, 69, 160. herak, m. (1991): dinaridi-mobilisticki osvrt na genezu i strukturu [dinarides – mobilistic view of the genesis and structures – in croatian].– acta geol., 21/2, 35–117. kapović, b. & bauer, v. (1970): sedimentološke, biofacijalne i ambijentalne karakteristike gornjokrednih naslaga otoka premuda i dugog otoka [sedimentary, biofacies and environmental characteristics of the upper cretaceous sediments of the premuda island and dugi otok – in croatian].– nafta, 22/12, 561–572. fi gu re 9: overall mean palaeomagnetic directions for localities tabulated in table 1 with confi dence circles (all normal polarities), and the individual palaeomagnetic directions for locality 9 (all reversed polarities), exhibiting great circle distribution. note that the great circle defi ned by the latter passes close to the cluster of the former. all directions are tilt corrected. fi gu re 10: overall mean palaeomagnetic directions with confi dence circles for the cenomanian–early senonian time period for the ist area, stable istria and the kvarner islands. stereographic projection, lower hemisphere. geologia croatica geologia croatica 62/2 114 kirschvink, j.l. (1980): the least-squares line and plane and the analysis of palaeomagnetic data.– geophys. j. roy. astro. soc., 62, 699–718. mamužić, p. (1970): osnovna geološka karta sfrj: 100 000, list molat l 33–138 [basic geological map of sfry 1:100 000, sheet molat – in cro atian].– savezni geološki zavod beograd. mamužić, p. & sokač, b. (1967). tumač za listove silba i molat l 33–126, l 33 138 [geology of the silba and molat sheets – in croatian].– savezni geološki zavod beograd, 45 p. mamužić, p., sokač, a. & velić, i. (1970): osnovna geološka karta sfrj 1:100 000, list silba l 33–126. [basic geological map of sfry 1:100 000, sheet silba – in croatian].– savezni geološki zavod beo grad. márton, e. (2006): palaeomagnetic evidence for tertiary counterclocwise rotation of adria with respect to africa.– in: pinter, n., grenerczy, gy., weber, j., stein, s. medak, d. (eds.): the adria microplate: gsp geodesy, tectonics and hazards. nato science series iv-61, 71–80. márton, e. & veljović, d. (1983): palaeomagnetism of the istria peninsula, yugoslavia.– tectonophys., 91, 73–87. doi: 10.1016/ 0040-1951(83)90058-6 márton, e. & veljović, d. (1987): palaeomagnetism of cretaceous carbonates from the northwestern part of the dinaric fold belt.– tectonophys., 134, 331–338. doi: 10.1016/0040-1951(87) 90345-3 márton, e., milicević, v. & veljović, d. (1990): palaeomagnetism of the kvarner islands, yugoslavia.– phys. earth plan. int., 62, 70–81. doi: 10.1016/0031-9201(90) 90193-2 márton, e. & milicević, v. (1994): tectonically oriented palaeomagnetic investigation in the dinarids, between zadar and split.– geophys. transact., 39, 4, 227–232. márton, e., pavelić, d., tomljenović, b., pamić, j. & márton, p. (1999): first palaeomagnetic results on tertiary rocks from the slavonian mountains in the southern pannonian basin, croatia.– geol. carpat., 50, 273–279. márton, e., pavelić, d., tomljenović, b., avanić, r., pamić, j. & márton, p. (2002): in the wake of a counterclockwise rotating adriatic microplate: neogene palaeomagnetic results from northern croatia.– int. j. earth sci., 91, 514–523. doi: 10.1007/ s00531-001-0249-4 márton, e., pavelić, d., tomljenović, b., márton, p. & avanić, r. (2005): palaeomagnetic investigations in the croatian part of the pannonian basin: a review.– acta geol. hung., 48/2, 225–233. doi: 10.1556/ageol.48.2005.2.8 márton, e., jelen, b., tomljenović, b., pavelić, d., poljak, m., márton, p., avanić, r. & pamić, j. (2006): late neogene counterclockwise rotation in the sw part of the pannonian basin.– geol. carpat., 57, 41–46. márton, e., drobne, k., cosovic, v. & moro, a. (2003): pala eo magnetic evidence for tertiary counterclockwise rotation of adria.– tectonophys., 337, 143–156. doi: 10.1016/j.tecto.2003.08.022 márton, e., cosović, v., moro, a. & zvocak, s. (2008): the motion of adria during the late jurassic and cretaceous: new palaeomagnetic results from stable istria.– tectonophys., 454, 44–53. doi: 10.1016/j.tecto.2008.04.002 mikes, t., báldi-beke, m., kázmér, m., dunkl, i. & eynatten, v. h. (2008): calcareous nannofossil age constrains on miocene fl ysch sedimentation in the outer dinarides (slovenia, croatia, bosnia-herzegovina and montenegro).– in: siegesmund, s., fügenschun, b. & froitzheim, n. (eds.): tectonic aspects of the alpine–dinaride–carpathian system. geological society, london, special publications, 298, 335–363. moro, a. (1993): litostratigtafi ja gornjokrednih naslaga otoka ista, oliba i silbe [lithostratigraphy of the upper cretaceous deposits of ist, olib and silba islands – in croatian, with an english summary].– unpubl. msc. thesis, faculty of science, university of zagreb, 60 p. moro, a. & jelaska, v. (1994): upper cretaceous peritidal deposits of olib and ist islands (adriatic sea, croatia).– geol. croat., 47/1, 53–65. moro, a., skelton, w.p. & ćosović, v. (2002): palaeoenvironmental setting of rudists in the upper cretaceous (turonian–maastrichtian) adriatic carbonate platform (croatia), based on sequence stratigraphy.– cretac. res., 23, 489–508. doi: 10.1006cres.2002. 1017 tari, v. (2002): evolution of the northern and western dinarides: a tectonostratigraphic approach.– egs stephan mueller publication series, european geophysical society, 1, 1–21. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeogr., palaeoclimatol., palaeoecol., 220, 333–360. doi: 10.1016/j.palaeo.2005.01.011 manuscript received november 21, 2008 revised manuscript accepted may 14, 2009 available online june 19, 2009 11-baldanza.indd 133 � ab stra ct plio-quaternary marine deposits are largely documented in western umbria (central italy), although they still lack biostratigraphic defi nition. contrary to published data, early pleistocene deposits outcrop more extensively than previously reported in the orvieto area. a composite biostratigraphic succession, almost continuous from the top of the g. gr. crassaformis zone to the top of the gl. cariacoensis zone, can be reconstructed in offshore clay sections. nannofossil assemblages and marker events (bmg, tcm, blg, ths, tlg) from the mnn16a to mnn19e subzones have been documented. lower shoreface – transition to offshore sections as described, are characterized by poor planktonic assemblages; nevertheless, they are still referable to the same stratigraphic interval. deposits can be partially inserted into the “chiani – tevere” depositional cycle, also documented in this area. moreover, marine conditions persist in the area from the base of the gelasian to the top of the calabrian, and it can be modelled as a peripheral, survival sea-branch, cut-off from the main river supply and from continental infl uence. however, zanclean to piacenzian deposits occur in a small area, localized around the town of orvieto, so the former distinction of superimposed depositional cycles can only be speculative. keywords: early pleistocene, calcareous nannofossil biostratigraphy, foraminifers, palaeoenvironmental reconstruction, western umbria. new biostratigraphic data from the early pleistocene tyrrhenian palaeocoast (western umbria, central italy) � angela baldanza1, roberto bizzarri1 and helmke hepach2 1department of earth science, university of perugia, p. za università 1 i-06123 perugia, italy; (abaldanz@unipg.it; roberto.bizzarri@libero.it) 2leibniz-institut fur meereswissenschaften (ifm-geomar), dusternbrooker weg 20, 24105 kiel, germany; (helmischnelm@gmx.de) doi: 104154/gc.2011.11 geologia croatica 64/2 133–142 3 figs. zagreb 2011 geologia croaticageologia croatica p.p. and gelasian p.p. – santernian respectively (am brosetti et al., 1987; girotti & mancini, 2003). the lithostratigraphic succession is represented by the informal units of “argille di fabro” (piacenzian), “sabbie a flabellipecten” (piacenzian), “conglomerati di città della pieve” (piacenzian p.p. – gelasian p.p.) and “argille e sabbie del chiani-tevere” (santernian p.p.) proposed by ambrosetti et al. (1987). girotti & piccardi (1994) 1. introduction the orvieto area (western umbria, central italy) documents the evolution of the tyrrhenian side of the northern apennines during the last 3.5 ma (fig. 1). the occurrence of coas tal marine environments is documented in the area from the piacenzian to the calabrian at least, and the palaeoenvironmen tal evolution has been classically reconstructed identifying two main sedimentary cycles: piacenzian p.p. – gelasian geologia croatica 64/2geologia croatica 134 figure 1: geological sketch of the study area and location of the study sections. the rocca ripesena (carboni, 1975), podere palombaro (carboni & di bella, 1996) and il caio sections (bizzarri et al., 2003) are also indicated. baldanza et al.: new biostratigraphic data from the early pleistocene tyrrhenian palaeocoast (western umbria, central italy) geologia croatica 135 and mancini et al. (2004) proposed the use of the “tenaglie unit” (zanclean – piacenzian) and the “chiani-tevere unit” (gelasian p.p. – santernian). new data from the orvieto area, (bizzarri et al., 2003, 2004; bizzarri, 2006), recently contributed to stratigra phic refi nement and a palaeoenvironmental review, and are only partially referable to the former stratigraphic scheme. this paper aims to present integrated sedimentological and micropalaeontological data of some early pleistocene sections recently recognized in the orvieto area, in order to place the reconstruction in the wider stratigraphic and palaeoenvironmental framework of western umbria. 2. geological setting the study area (fig. 1) is located in western umbria (central italy), near the town of orvieto, along the lower paglia -tiber valley, a graben basin limited by eastand west-dipping conjugated normal fault systems, formed as a consequence of lower pliocene tectonics (funiciello et al., 1981; aavv, 1982). the basin accommodated coastal marine environments from the early pliocene to the santernian (ambrosetti et al., 1977; 1978a; 1987; girotti & mancini, 2003; mancini et al., 2004) or emilian (bizzarri et al., 2004; bizzarri, 2006; bizzarri & baldanza, 2006a, 2007). the study area is bounded to the east by the narnese-amerina range, to the west by the rapolano-cetona range, and by the vulsini late pleistocene volcanic district to the south-west (fig. 1). the pre-pliocene basement is mainly represented on the rapolano-cetona range by cretaceous to eocene scaglia tos cana s.l.-ligurids units, whereas on the narnese-amerina range it is represented by the tuscan oligo-miocene macigno s.l. unit in the northern part, and by the umbriamarche carbonate succession (triassic-oligocene) in the south (jacobacci et al., 1967, 1969, 1970; fazzini, 1968; da miani et al., 1993). pliocene-pleistocene deposits unconformably overlie the rocky basement on both sides of the valleys, up to 500-600 m a.s.l., displaced by early-middle pleistocene and late pleistocene-holocene tectonics (ambrosetti et al., 1978b; cattuto et al., 1979; funiciello et al., 1981; aavv, 1982). late pliocene tectonics (ambrosetti et al., 1977; 1978b; 1987, 1989; cattuto et al., 1979, 1983, 1997) have often been overestimated as being the cause of the attitude of present-day deposits (bizzarri, 2006). 3. study sections data from seven recently described sections (bizza r ri et al., 2005; bizzarri, 2006; bizzarri & baldanza, 2006b, 2007), covering a wide area around the orvieto town are presented. new data are also correlated with the three reference sections of the rocca ripesena (carboni, 1975), podere palombaro (carboni & di bella, 1996) and il caio (bizzarri et al., 2003) (figs. 1, 2). 3.1. allerona quarries in the clay quarries north of the allerona railway station on the western side of the paglia valley, a composite section, about 50 m thick has been reconstructed (figs. 1, 2), divided into lower and upper portions respectively, separated by a 10 m gap. the deposits are represented by grey-blue, massive to thin – laminated silty clay. the fossil content is mainly represented by scattered gastropods and bivalve coquinas. the microfossil assemblage is characterized by ostracods including aurila sp., cytheropteron alatum and c. testudo, and rich foraminifer assemblages (fig. 3). the basal portion of the section contains poor calcareous nannofossil assemblages with small gephyrocapsa, calcidiscus macintyrei and discoaster spp., referable to the mnn16a-mnn18 zone (piacenzian – gelasian pp.). higher in the section, the calcareous nannofossil assemblages are well preserved allowing identifi cation of the gelasian-calabrian interval, continuous from the mnn19a to the mnn19d subzones. the bmg and blg nannofossil events are observed, marking the base of the mnn19b and mnn19b subzones, respectively. 3.2. camorena the camorena section outcrops in badlands 3 km south-east of orvieto (fig. 1), where an early pleistocene marine succession is exposed. the section is about 50 m thick (fig. 2) and is exclusively composed of laminated, grey-blue clay/ silty clay. analysis concentrated on continuous measurement and sampling of a 36 m thick clay succession in the upper part of the section. samples from the basal part show micropalaeontological assemblages characteristic of the base of the calabrian, with the occurrence of globorotalia infl ata and hyalinea balthica. two pyroclastic, pyroxene-bearing interbeds occur (bizzarri et al., 2004) between 2.20 m and 3.50 m and at 15.50 m respectively. these are in the mnn19c and mnn19d subzones, are biostratigraphically constrained at 1.619 ma and ~1.50 ma respectively and correlate to volcanoclastic deposits documented in the il caio section (bizzarri et al., 2003). the camorena section covers the interval from the mnn19b to mnn19e subzones. a basal fossil assemblage is characterized by small gephyrocapsa, medium gephyrocapsa and calcidiscus macintyrei, marking an early pleistocene age referable to the mnn19b subzone. the last oc currence (lo) of c. macintyrei, followed by the first occurrence (fo) of large gephyrocapsa, allows identifi cation of the mnn19c subzone. finally the lo of large gephyrocapsa marks the base of the mnn19e subzone. the lo of helicosphaera sellii and a scattered increase of braarudosphaera bigelowii occur into the mnn19d subzone. among foraminifers, globigerina cariacoensis occurs at the base of the section, in an assemblage with globorotalia infl ata. hyalinea balthica is also present. 3.3. sugano well on the western side of the paglia valley, 4 km south of orvieto, near sugano, a water well was recently drilled through geologia croatica 64/2geologia croatica 136 figure 2: sedimentological and stratigraphic logs of the study sections, grouped according to palaeoenvironmental attribution. the fan-delta section of il caio (bizzarri et al., 2003) is also shown. baldanza et al.: new biostratigraphic data from the early pleistocene tyrrhenian palaeocoast (western umbria, central italy) geologia croatica 137 figure 3: semi-quantitative distribution chart of selected benthonic and planktonic foraminifers from the study sections. length of lines is proportional to section thickness. sw=sugano well. geologia croatica 64/2geologia croatica 138 landslide deposits (4 m) and vulsini mts. volcanic deposits (9 m), reaching the underlying grey-blue marine clay. samples recovered, contain both a rich and well preserved microfauna and pyroclastic minerals (pyroxenes) and pumice. the foraminifer assemblages (fig. 3) are associated with the ostracods cytheropteron alatum and aurila sp. the section also produced a very rich calcareous nannofossil assemblage which is characterized, in the lowermost sample, by small gephyrocapsa and medium gephyrocapsa referable to the mnn19c subzone. the fi rst occurrence of large gephyrocapsa specimens, in the uppermost part of the section, marks the base of the mnn19d subzone. 3.4. osarella ii the section (bizzarri, 2001, 2006) is located along the ss 79 bis road at about 275 m a.s.l. it is represented by 18 m of sandy deposits, and comprises three intervals: interval 1 – the lowermost 7 m are represented by well sorted fi ne sand to silty sand. massive, bioturbated levels and thin laminated horizons almost regularly alternate. planar to undulate lamination is organized in 10–40 cm thick horizons which regularly alternate with massive beds. lamina sets (<5cm thick) repeat at a 1–1.5 cm interval, and each lamina is 3–4 mm in thickness. lamination is marked by rhythmic colour and minimal grain size variations. water escape structures (convolute lamination) also occur locally. bioturbation is not organized and is identifi ed as thalassinoides isp.; it locally alternates with shell horizons and scattered large gastropods and bivalves (natica tigrina, trachelochetus romanus, neverita josephinia, ostrea lamellosa, hynia prismatica). interval 2 is 5 m thick and composed of moderately sort ed medium to coarse grained sand beds. in spite of diffuse bioturbation, still referable to thalissinoides isp., each bed is characterized by an erosional base, a lithoand bioclastic lag, normal gradation and, in the uppermost part, faint cross-lamination. the fossil content is poor, but still represented predominantly by molluscs. interval 3 in the uppermost part of the section, alternates well sorted fi ne sand beds with horizons composed of large oysters, pectinids and other bivalves. thalassinoides traces still occur, often emphasizing the original morphology at the base of shell beds. furthermore, a 25 cm thick, oligotypic large glicymeris sp. horizon characterizes the base of the interval, whereas a 50 cm thick bed composed of echinoid fragments occurs in the uppermost part. this section contains nannofossil assemblages referable to the mnn19b and c subzones. the foraminiferal assemblages are poor and dominated by shallow water benthic species (fig. 3). it is interesting to note the presence, although rare, of globigerina cariacoensis in the assemblage with globorotalia infl ata. 3.5. la casella the section has been described along the ss 71 road at the 41 km mark (bizzarri, 2001, 2006), and extends for about 25 m, between 150 and 175 m a.s.l. (fig. 1). sedimentological features allow differentiation of two intervals: interval 1 is represented in the lowermost 13 m by well sorted, grey to blue very fi ne sand and silty sand. beds appear massive, due to bioturbation (mainly thalassinoides isp., but also “v” shaped indeterminate forms). they are occasionally interbedded with up to 10 cm thick, medium to coarse grained sandy lithoclastic lags. the bioturbation increases in the last few metres, where wavy to gently cross laminations also occur. gastropods and bivalves (thericium sp., hynia sp., natica sp., glans sp. and ostrea spp.) also increase upwards, although shell fragments are documented throughout the section. interval 2 is characterised by 10 m of well sorted fi ne to very fi ne grained, yellowish sand. the sediments are massive, with dispersed large scattered bivalves and gastropods and common thalassinoides isp. traces. they are interrupted by irregular intervals of bioclastic lags, often bioturbated, and by horizons of large oysters and pectinids, mainly made of ostrea lamellosa, chlamys spp. and flabellipecten fl abelliformis. barnacles also locally occur. the microfossil content (fig. 3) is dominated by shallow water benthonic taxa. the section comprises calcareous nannofossil assemblages characterized by small gephyrocapsa, medium gephyrocapsa and c. macintyrei in the basal samples. the disappearance of c. macintyrei, in the middle part of the section, allows identifying both the mnn19b and 19c subzones. 3.6. baschi railway the section outcrops along the ss 205 road (fig. 1), near the baschi train station (bizzarri, 2001, 2006). it is 12 m thick, and represented by well sorted, grey to yellowish, fi ne grain ed sand and silty-sand. the lowermost part is characterized by wavy to faint cross lamination, organized in 5 cm thick lamina sets, and by pervasive thalassinoides isp. bioturbation. both bioclastic lags and large oyster and pectinid coquinas occur throughout the section. large, scattered bivalve and scaphopod specimens (glans sp., thericium sp., chlamys spp., haustator vermicularis, aporrhais sp., ostrea lamellosa, ostrea sp., dentalium spp.) have been recognized. the section allows reconstruction of a succession of calcareous nannofossil events which document the mnn19 a and b subzones. 3.7. castellunchio the 10 m reconstructed section, located in the vicinity of the baschi railway section (fig. 1), is represented by massive, gray-blue very fi ne sand and silty sand. g. cariacoensis and g. infl ata are recognized from the base of the section, whereas hyalinea balthica occurs in the uppermost part. the outcrop is attributable to the mnn19b and c nannoplancton subzones. 3.8. previous reference sections for the study area rocca ripesena – a section in clay deposits, approximately 60 m thick, was reconstructed by carboni (1975), a few baldanza et al.: new biostratigraphic data from the early pleistocene tyrrhenian palaeocoast (western umbria, central italy) geologia croatica 139 kilometres west from orvieto, not far from the sugano well site, (fig. 1). samples were collected from between 200 – 250 m a.s.l. the author, attributed the section to the piacenzian, mainly on the basis of g. gr. crassaformis distribution. the landscape has been strongly modifi ed during the last 30 years, and the exposure today appears very different with respect to the original. yet, the rocca ripesena area has been newly sampled, between 250 – 260 m a.s.l., which is about at the top of the old section of carboni (1975). samples document a very rich and preserved nannofossil assemblage, referable to the mnn 19 c subzone. h. balthica and g. cariacoensis also occur. as a pliocene age cannot be totally rejected for the base of the section, the new data allow reference of the top to the calabrian. pod. palombaro – carboni & di bella (1996) analyzed the podere palombaro section (near orvieto) and documented a pleistocene age for this clayey sequence outcropping on the left bank of the paglia river, which was attributed to the piacenzian (carboni, 1975; barberi et al., 1994) or pliocene/pleistocene age (ambrosetti et al., 1987). the studied sediments were correlated to the chiani-tevere sandy clay formation (argille e sabbie del chiani-tevere, ambrosetti et al., 1987), on the base of benthic foraminiferal assemblages. the p. palombaro represented the “key section” that allowed the authors to identify the early pleistocene (g. cariacoensis zone), where the age of exposed pleistocene sediments “has always been debated” because of the lack of planktonic markers (carboni & di bella, 1996). several samples (not in situ) were recently collected nearby, which confi rm the previous data, and furthermore, hyalinea balthica is also present. the nannofossil assemblages are attributable to the mnn19c subzone, thus confi rming the presence of early pleistocene deposits in the pod. palombaro area. il caio – detailed analysis of the il caio section (figs.1, 2) is reported in bizzarri et al. (2003) and bizzarri (2006). deposits are represented by shoreface sand, with distal alluvial gravel, in the lowermost part, by prodelta silt and clay in the intermediate part and by alluvial fan gravel and sand in the upper part (fig. 2). a fan delta environment was reconstructed (bizzarri et al., 2003; bizzarri, 2006). new sampling of this section, complemented by mineralogical analysis of volcanoclastic episodes, allows better understanding of its stratigraphy. the base of the section is devoid of calcareous nannofossils because of the predominantly medium sand grain size. the middle-upper portion is instead characterized by a thin interval of silt to clay sediments; the samples here contain good calcareous nannofossil assemblages which are characterized by abundant small gephyrocapsa, common medium gephyrocapsa and very few specimens of c. macintyrei. the microfossil assemblages are re presented by globorotalia infl ata and globigerina cariacoensis. this interval has been attributed to the early pleistocene (mnn19b subzone) and the presence of g. cariacoensis documents a santernian age. the occurrence of py ro xene crystals, micas and pumice dispersed in marine fi ne grained sediments, documents the presence of a volcanoclastic event that can be attributed to the santernian and precedes those found in the camorena section. 4. discussion 4.1. sedimentological evidences and palaeoenvironmental reconstruction the study sections belong to a distal low energy marine environment, in front of a beach, alternately dominated by deposition and wave action. the correlatable proximal deposition, (not considered here except for the il caio section), is represented by beachface gravel and cross-stratifi ed upper shoreface sand. all proximal and distal deposits belong to a river-fed coastal system, supplied by a number of local alluvial fans draining both sides of the valley (bizzarri, 2006, 2007). the monotonous clay-silty clay sequences of the allerona quarries, camorena and sugano well outcrops were deposited below wave base, and provide evidence of an offshore environment, with a maximum depth ranging from 80 to 120 m. sieve analyses reveal a high percentage (98.5 to 99.3%) of grains fi ner than 0.63 mm (4 φ of the hudden-wentworth scale). according to dunbar & barrett (2005), grain size 4 φ represents the real borderline for settling processes, at least in marine environments, where more than 80% of grains fi ner than 4 φ is indicative of a settling-dominated offshore environment, with a minimum 60 m water depth. the foraminiferal assemblages, indeed, are dominated by planktonic specimens and by low-oxygen taxa rather than by deep water benthonic specimens (fig. 3). alternatively, the other four sections document a faint wave action, and are referable to an environment across the transition to offshore and the lower shoreface. normally grad ed beds, as well as bioclastic lags and shell beds, are interpreted as tempestites. the baschi railway and castellunchio sections document no environmental modifi cation. conversely, the la casella and osarella ii sections show a slight shallowing upward trend, from transition to offshore to lower shoreface. concerning the foraminifers (fig. 3), these four sections are dominated by shallow water proximal specimens, whereas planktonic taxa rarely occur. 4.2. stratigraphic data the seven sections presented above allow recognition of an almost continuous stratigraphic succession of marker events, from the piacenzian to the uppermost calabrian. the nannofossil assemblages are of medium – good preservation, and are characterized by the common presence of gephyrocapsidae, reticulofenestridae, calcidiscidae and coccolithus pelagicus. furthermore, the low abundance of specimens only allows a semi-quantitative approach, to evaluate the distribution of the most signifi cant taxa. moreover, a variable number of reworked specimens (from cretaceous to miocene) are present. calcareous nannofossil events documented in the seven successions are totally comparable to those found in the western mediterranean (di stefano, 1998; de kaenel et al., 1999; raffi, 2002). the datum agrees with the occurrence of g. infl ata in all of the sections (except for the la casella section), and with the occurrence of gl. cariacoensis in four of the secgeologia croatica 64/2geologia croatica 140 tions (figs. 2, 3), documenting the g. infl ata and gl. cariacoensis zones, according to the schemes of colalongo & sartoni (1979) and iaccarino & premoli silva (2007). the lowermost allerona quarries section, on the basis of the nannofossil and foraminiferal assemblages, belongs to the g. gr. crassaformis zone and ranges from the mnn16a to mnn18 nannofossil zones. biostratigraphic data and sedimentological analyses, document uninterrupted late gelasian-calabrian marine sedimentation in the orvieto area for the fi rst time. moreover, the offshore succession seems to be continuous and concordant, at least since the late pliocene. finally, a brief remark on the benthonic specimen hyalinea balthica is opportune. h. balthica is commonly documented at 6 of the sections, in sediments varying from clay to silt, to fi ne sand, proving that its presence is independent of grain size. the lowermost fi rst local datum for the taxon occurs inside the mnn19b subzone, at the base of the calabrian, still supporting the early pleistocene age for the orvieto area deposits. the fi rst appearance datum of h. balthica, well-known as a “cold guest” marked the santer nian -emilian boundary (azzaroli et al., 1997), particularly in the adriatic successions. in the orvieto area, the fi rst occurrence of h. balthica occurs in the santernian, and is thus signifi cantly earlier. in our sections, h. balthica is widely and continuously documented in offshore deposits (fig. 2), and often in an assemblage with both deep water benthic and deeper planktonic microorganisms (fig. 3). furthermore, the occurrence of h. balthica suggests isolation and cooling at the sea-fl oor (ross, 1984; bergamin & di bella, 1997), which is a possible consequence of sea-water column stratifi cation. these palaeoecological inferences are preliminary, and a broa der approach is needed. at the moment, our data lower the taxon appearance, which thus can be considered a seafl oor palaeotemperature proxy, whereas its stratigraphic importance needs to be reconsidered. 4.2.1. volcanoclastic horizons in the il caio section (fig. 2), the occurrence of distal pyroclastic fallout material has been recently suggested (bizzar ri et al., 2003). as described above (sections 3.2, 3.3), similar volcanoclastic deposits, mainly represented by leucite-bearing pumice and idiomorphic pyroxenes, occur in the camorena and sugano well sections (fig. 2), attributed to early pleistocene (bizzarri et al., 2003; bizzarri, 2006). new analyses involving the il caio section, (still in progress (pandolfi, 2006; peccerillo et al., 2010a, 2010b)), attest to an affi nity with the roman comagmatic province. the new calcareous nannofossil stratigraphic data indicate that the lowermost volcanoclastic event occurred during the mnn 19b subzone, whereas a late villafranchian freshwater mollusc assemblage in the upper part of the section (bizzarri et al., 2003), indicates an age older than 1.4 ma for its uppermost part (fig. 2). as a consequence, the age of the uppermost volcanic products can be approximated in a range between 1.4 ma and 1.62 ma. similar age constraints characterize marine deposits in the other four outcrops, where distal fallout deposits cover a time span of about 300 ky (mnn 19 b–d subzones). biostratigraphic constraints clearly mark the occurrence of three successive steps in volcanic activity, from the mnn 19b to the mnn 19d subzones (fig. 2). the source of volcanics was probably a small, still unknown eruptive centre, and its discontinuous activity covered a time span of at least 300 ky (peccerillo et al., 2010b). the correlation of these events looks reliable, and its age constraint is different from that of the middle pleistocene “paleobolsena” volcanic event (santi, 1990; gillot et al., 1991; nappi et al., 1994). 5. conclusion the stratigraphic reconstruction contributes to our understanding of evolution of the tuscan-umbria-latium area. start ing from the mid 1970’s, pliocene and pleistocene deposits in the area have been referred to two 3rd order sedimentary cycles, separated by the “acquatraversa” erosion/ tectonic phase (blanch, 1955; ambrosetti et al., 1977; 1987; girotti & mancini, 2003; mancini et al., 2004). none of the authors recorded marine deposits after the santernian, so the ultimate marine regression must have already occurred in the early pleistocene. all of the studied sections belong to the same environmental domain, and to the same depositional cycle (“chiani – tevere” cycle: ambrosetti et al., 1987; girotti & mancini, 2003; mancini et al., 2004), even though the temporal extension of that cycle (gelasian pp.–santernian) seems to be limited. the micropalaeontological content allows detailed stratigraphic reconstruction, with identifi cation of the calcareous nannoplankton zone mnn19 (rio et al., 1990) and relative mnn19a to mnn19e subzones. moreover, lithological and sedimentological data confi rm both lateral and vertical environmental continuity, and the lack of major unconformities do not allow defi nition of a lithostratigraphic unit limit. con sidering the new data presented herein, stratigraphic revision seems to be necessary, as well as re-interpretation of the palaeogeographic patterns. the data confi rm the persistence of marine conditions in the orvieto area from the gelasian to the top of the calabrian at least, either unor only partially infl uenced by continental progradation, unlike the southern areas, where a continental environment is already documented, from the santernian (girotti & mancini, 2003; mancini et al., 2004). the orvieto area can be illustrated as a restricted satellite basin in which marine conditions remain, protected from the infl uence of the main rivers during the early pleistocene and accommodating only negligible supply from tributary rivers (bizzarri, 2006). contrary to former palaeogeographic interpretations, the occurrence of early pleistocene marine deposits is largely documented in the orvieto area. the offshore clay deposits allow reconstruction of a composite biostratigraphic succession (fig. 2), almost continuous from the top of the g. gr. crassaformis zone to the top of the gl. cariacoensis zone. baldanza et al.: new biostratigraphic data from the early pleistocene tyrrhenian palaeocoast (western umbria, central italy) geologia croatica 141 as expected, the datum becomes less clear in more proximal marine deposits. nevertheless, nannofossil assemblages and bioevents still allow reference of these deposits to the mnn19a, mnn19b and mnn19c subzones. deposits can be partially attributed to the “chiani – tevere” depositional cycle, which thus also appears largely documented in the study area. references aavv (1982): bacino del fiume paglia (umbria – toscana): studi strutturali, idrogeologici e geochimici.– relazione fi nale sul tema di ricerca: ” studi geologici, idrogeologici e geofi sici fi nalizzati alla ricerca di fl uidi caldi nel sottosuolo”. cnr – progetto finalizzato energetica, 16, 112 p. ambrosetti, p., carboni, m.g., conti, m.a., costantini, a., esu, d., gandin, a., girotti, o., lazzarotto, a., maz zanti, r., nicosia, u., parisi, g. & sandrelli, f. (1978a): evoluzione paleogeografi ca e tettonica nei bacini tosco – umbro – laziali nel pliocene e nel pleistocene inferiore.– mem. soc. geol. it., 19, 573–580. ambrosetti, p., cattuto, c., conti, m.a., nicosia, u. & parisi, g. (1978b): dati preliminari sulla neotettonica del foglio 130 (orvieto).– contributi preliminari alla realizzazione della carta neo tettonica d’italia: c.n.r. – progetto finalizzato geodinamica, 155, 391–397. ambrosetti, p., conti, m.a., parisi, g., kotsakis, t. & nicosia, u. (1977): neotettonica e cicli sedimentari plio-pleistocenici nei dintorni di città della pieve (umbria).– boll. soc. geol. it., 96, 605–635. ambrosetti, p., carboni, m.g., conti, m.a., esu, d., girotti, o., la monica, g.b., landini, b. & parisi, g. (1987): il pliocene ed il pleistocene inferiore del bacino del fiume tevere nell’umbria meridionale.– geogr. fis. dinam. quat., 10, 10–33. ambrosetti, p., cattuto, c. & gregori, l. (1989): geomorfologia e neotettonica nel bacino di tavernelle/pietrafi tta (umbria).– il quaternario, 2/1, 57–64. azzaroli, a., colalongo, m.l., nakagawa, h., pasini, g., rio, d., ruggieri, g., sartoni, s. & sprovieri, r. (1997): the pliocene-pleistocene boundary in italy.– in: van couvering, j.a. (ed.): the pleistocene boundary and the beginning of the quaternary. cambridge university press, cambridge, 141–155. barberi, f., buonasorte, g., cioni, r., fiordelisi, a., foresi, l., iaccarino, s., laurenzi, m.a., sbrana, a., ver nia, l. & villa, i.m. (1994): plio-pleistocene geological evolution of the geothermal area of tuscany and latium.– mem. descr. carta geol. it., 49, 77–134. bergamin, l. & di bella, l. (1997): hyalinea balthica (schroeter): the ecological signifi cance of infl ated and compact phenotypes in circalittoral environments.– palaeopelagos, 7, 133–143. bizzarri, r. (2001): facies costiere plioceniche nell’area di corbara (orvieto).– unpubl. degrees thesis, perugia university, perugia, 169 p. bizzarri, r. (2006): depositi plio-pleistocenici tra la val di chiana e il lago di corbara: caratterizzazione sedimentologica e ricostruzione paleoambientale. –unpubl. phd thesis, perugia university, perugia, 408 p. bizzarri, r. (2007): late pliocene-early pleistocene fl uvial paleocoasts in western umbria (central italy): facies analysis and sedimentation models.– geoitalia epitome, 2, 393–394. bizzarri, r. & baldanza, a. (2006a): stratigrafi a e cicli sedimentari nel pleistocene inferiore dell’area orvietana (umbria, italia centrale): considerazioni sull’unità del chiani-tevere.il sollevamento quaternario nella penisola italiana e nelle aree limitrofe, aiqua national meeting, rome, feb. 6-8, 2006.– abstract book, 23–24. bizzarri, r. & baldanza, a. (2006b): on the meaning of the amphistegina levels in the plio – pleistocene of the orvieto area (central italy).– in: coccioni, r. & marsili, a. (eds.): proceedings of the second and third italian meetings on environmental micropaleontology. grzybowski foundation special publication, 11, 13–20. bizzarri, r. & baldanza, a. (2007): late pliocene and early pleistocene of the orvieto area (central italy): a stratigraphic review.– geoitalia epitome, 2, 399. bizzarri, r. & baldanza, a. (2009): plio-pleistocene deltaic deposits in the città della pieve area (western umbria, central italy): facies analysis and inferred relations with the south chiana valley fl uvial deposits.– il quaternario, 22/2, 127–138. bizzarri, r., ambrosetti, p., argenti, p. & baldanza, a. (2004): il pleistocene inferiore in facies marina nei dintorni di corbara (orvieto, italia centrale): gli affi oramenti di camorena e del caio. la geologia del quaternario in italia: temi emergenti e zone d’ombra, aiqua national meeting, rome, feb. 16–18, 2004.– abstract book, p. 100. bizzarri, r., ambrosetti, p., argenti, p., gatta, g.d. & baldanza, a. (2003): l’affi oramento del caio (lago di corbara, orvieto, italia centrale) nell’ambito dell’evoluzione paleogeografi ca plio – pleistocenica della valle del tevere: evidenze sedimentologiche e stratigrafi che.– il quaternario, 16/2, 240–255. bizzarri, r., passeri, l. & baldanza, a. (2005): rocky coasts, sand and gravel beaches from late pliocene and early pleistocene of the orvieto area (western umbria, central italy).– geoitalia epitome, 1, 166. blanch, a.c. (1955): giacimento paleolitico inferiore di torre in pietra e giacimenti levalloiso – musteriani di palo e di palidoro.– quaternaria, 2, 305–308. carboni, m.g. (1975): biostratigrafi a di alcuni affi oramenti pliocenici del versante tirrenico dell’italia centrale.– geol. rom., 14, 63–86. carboni, m.g. & di bella, l. (1996): the pleistocene section of podere palombaro (umbria).– geol. rom., 32, 97–108. cattuto, c., conti, m.a., nicosia, u. & parisi, g. (1979): relazione sulla neotettonica dei fogli 130, 131, 137 e 138.– contributi preliminari alla realizzazione della carta neotettonica d’italia: c.n.r.– progetto finalizzato geodinamica, 251, 13–28. cattuto, c., cencetti, c. & gregori, l. (1997): un vistoso esempio di controllo strutturale e di morfogenesi fl uviale tra todi e baschi (fg.130 carta d’italia).– il quaternario, 10, 181–190. cattuto, c., gregori, l. & parisi, g. (1983): indizi di tettonica pleistocenica nel bacino del t. tresa (lago trasimeno).– geogr. fis. dinam. quat., 1, 16–20. colalongo, m.l. & sartoni, e. (1979): schema biostratigrafi co per il pliocene ed il pleistocene in italia.– contributi preliminari alla carta neotettonica d’italia, 251, 645–654. damiani, a.v., mencarelli, i. & piazzoli, s. (1993): studi sulla catena preappeninica umbra. la dorsale del m.peglia-nota i. con siderazioni e problematiche relative alla successione etrusca.– bollettino del servizio geologico italiano, 109, 105–136. de kaenel, e., siesser, w.g. & murat, a. (1999): 13. pleistocene calcareous nannofossil biostratigraphy and western mediterranean sapropels, sites 974 to 977 and 979.– in: zhan, r., comas, m.c. & klaus, a. (eds.): proceeding odp scientifi c results, 161, 159–183. doi: 10.2973/odp.proc.sr.161.250.1999 di stefano, e. (1998): calcareous nannofossil quantitative biostratigraphy of holes 969e and 963b (eastern mediterranean).– in: robgeologia croatica 64/2geologia croatica 142 ertson, a.h.f., eimes, k.c., richter, c. & camerlenghi, a. (eds.): proceeding odp scientifi c results, 160, 99–112. doi:10.2973/odp.proc.sr.160.009.1998 dunbar, g.b. & barrett, p.j. (2005): estimating palaeobathymetry of wave-graded continental shelves from sediment texture.– sedimentology, 52, 235–254. doi: 10.1111/j.1365-3091.2004.00695.x fazzini, p. (1968): la geologia dei monti d’amelia (tr).– mem. soc. geol. it., 7, 441–469. funiciello, r., parotto, m. & praturlon, a. (1981): carta neotettonica d’italia – cnr – progetto finalizzato geodinamica, 269 p. gillot, p.y., nappi, g., santi, p. & renzulli, a. (1991): spacetime evolution of the vulsini volcanic complexes, central italy.– terra abstract, 3/1, 446. doi: 10.1111/j.1365-3121.1991.tb00859.x girotti, o. & mancini, m. (2003): plio – pleistocene stratigraphy and relations between marine and non – marine successions in the middle valley of tiber river (latium, umbria).– il quaternario, 16, 89–106. girotti, o. & piccardi, e. (1994): linee di riva del pleistocene inferiore sul versante sinistro della media valle del f. tevere.– il quaternario, 7, 525–536. iaccarino, s. & premoli silva, i. (2007): practical manual of neogene planktonic foraminifera.– international school on planktonic foraminifera, vi course: neogene, perugia, feb. 19–23, 2007. jacobacci, a., malatesta, a. & martelli, g. (1969): note illustrative della carta geologica d’italia alla scala 1:100000; foglio 121 “montepulciano”.– italian geological survey, 73 p. jacobacci, a., martelli, g. & nappi, g. (1967). note illustrative della carta geologica d’italia alla scala 1:100000; foglio 129 “santa fiora”.– italian geological survey, 61 p. jacobacci, a., bergomi, c., centamore, e., malatesta, a., malferrari, n., martelli, g., pannuzzi, l. & zattini, n. (1970): note illustrative della carta geologica d’italia alla scala 1:100000; fogli 115 “città di castello”, 122 “perugia”, 130 “orvieto”.– italian geological survey, 147 p. mancini, m., girotti, o. & cavinato, g.p. (2004): il pliocene ed il quaternario della media valle del tevere (appennino centrale).– geol. rom., 37, 175–236. nappi, g., capaccioni, b., renzulli, a., santi, p. & valentini, l. (1994): stratigraphy of the orvieto-bagnoregio ignimbrite eruption (eastern vulsini district, central italy).– memorie descrittive della carta geologica d’italia, 49, 241–254. pandolfi, d. (2006): analisi petrologica e geochimica delle vulcaniti della sezione del caio (corbara, umbria occidentale).– unpubl. bs. thesis, perugia university, 140 p. peccerillo, a., bizzarri, r., baldanza, a., petrelli, m. & famiani, f. (2010a): early pleistocene remote pyroclastic fallout material in western umbria continental and marine deposits: composition, provenance and correlation potentiality. “le correlazioni marino – continentali nel quaternario”, aiqua national meeting, bari, feb. 25–26, 2010.– abstract book, 30–31. peccerillo, a., bizzarri, r., baldanza, a., petrelli, m. & famiani, f. (2010b): early pleistocene distal pyroclastic-fallout material in continental and marine deposits of western umbria (italy): chemical composition, provenance and correlation potential.– il quaternario, 23/2, 231–236. raffi, i. (2002): revision of the early – middle pleistocene calcareous nannofossil biochronology (1.75-0.85 ma).– mar. micropaleontol., 45, 25–55. doi: 10.1016/s0377-8398(01)00044-5 rio, d., raffi, i. & villa, g. (1990): pliocene-pleistocene calcareous nannofossil distribution patterns in the western mediterranean.– in: kastens, k. & mascle, j. (eds.): proceeding odp scien tifi c results, 107, 513–533. doi:10.2973/odp.proc.sr.107.164. 1990. ross, c.r. (1984): hyalinea balthica and its late quaternary paleoclimatic implications: strait of sicily.– j. foramin. res., 14/2, 134– 139. doi: 10.2113/gsjfr.14.2.134 santi, p. (1990): new geochronological data of the vulsini volcanic district (central italy). “genesi e differenziazione del magmatismo potassico del bordo tirrenico”.– simp meeting, ischia, 15–18 ottobre 1990. manuscript received september 17, 2010 revised manuscript accepted february 24, 2011 available online june 09, 2011 1. introduction in the north-western part of croatia, belonging to the south pannonian basin, numerous small occurrences of miocene volcanic and volcaniclastic rocks have been discovered (©imuni∆ et al., 1981; ani»i∆ & juri©a, 1985; pami∆, 1997 and references therein). according to the comprehensive work of pami∆ (1997), neogene volcanic rocks could be divided into four groups: egerian eggenburgian, karpatian, badenian and post-badenian. the age of volcanic and volcaniclastic rocks could be determined by radiometric methods or on the basis of field relationships with associated sediments. radiometric methods are still not easily available, while scarce and poor exposures, due to the vegetation cover and tectonic deformation, often make it difficult to establish the correlation between sediments and volcanic rocks. the aim of this work (which forms a part discriminant function analysis of miocene volcaniclastic rocks from north-western croatia based on geochemical data darko tiblja© 1, vanja lopari∆1 and mirko belak 2 of a detailed investigation of volcaniclastic rocks in the area) was to see if any significant difference in geochemical characteristics of the rocks of different ages exists, i.e. to determine the geochemical fingerprint of rocks of different ages. the theoretical background for the analysis lies in the fact that the composition of volcanic rocks depends on the geotectonic settings which changed during the evolution of pannonian basin, and therefore should be recorded in the chemical composition of the rocks. positive results could help distinguish rocks of unknown age. for this purpose we used statistical methods, principally the discriminant function analysis, which is a powerful technique for classifying individual cases (samples) into previously defined groups on the basis of multiple variables, and one which has a broad application in determining solutions for geoscience problematics (davis, 1986). 2. materials and methods in the scope of our research we investigated miocene volcanic and volcaniclastic rocks, as well as rocks for which they were the origin, e.g. bentonites, that crop out in north-western croatia, along the easternmost segment of periadriatic fault system, from the slovenian border to the varaædinske toplice. we analysed andesites from cerovec (sample t-6-94b) and lepoglava, dacites from trliëno (t-5-93-17) and donje jesenje (t6-93-17e), bentonites from poljanska luka and ©aπa, and tuffs (sensu lato) from the areas of hromec, jesenje cerje jesensko, lapornica ©eprun, jamno, vuglovec, podrute, moæenec, and kalnik mountain (fig. 1). in addition to these newly collected samples we analysed samples of rocks from moæenec, described by ki©pati∆ (1909), that are deposited in the croatian natural history museum (catalogue numbers 600: zag; 7113 and 7115: mp1). according to available data, the samples from poljanska luka are badenian (ani»i∆ & juri©a, 1985), those from trliëno, hromec, jesenje, cerje jesensko, jamno, lepoglava and vuglovec are of egerian eggenburgian age (©imuni∆ & pami∆, 1993) as are those from podrute (©imuni∆ et al., 1981). volcaniclastic rocks from ©aπa, lapornica and ©eprun areas are interstratified with clasgeologia croatica 55/1 39 44 2 figs. 4 tabs. zagreb 2002 key words: volcaniclastic rocks, discriminant function analysis, geochemical data, miocene, pannonian basin, croatia. 1 institute of mineralogy and petrography, faculty of science, horvatovac b.b., hr-10000 zagreb, croatia. e-mail: darko.tibljas@jagor.srce.hr 2 institute of geology, sachsova 2, hr-10000 zagreb, croatia. abstract preliminary results of discriminant function analysis of geochemical data of miocene volcanic and volcaniclastic rocks revealed that it is possible to distinguish rocks of different ages, namely egerian eggenburgian, karpatian and badenian. on the basis of calculated coefficients of classification functions, presented in the paper, it is possible to indicate the age of miocene volcanic and volcaniclastic rocks if their trace element content is known. the analysis also showed that, especially in the case of volcaniclastic rocks, the mineral and petrological composition of the rocks should also be considered. most of the investigated volcaniclastic rocks from the moæenec and kalnik areas, the age of which was unknown, are, according to discriminant function analysis, of egerian eggenburgian age. 40 geologia croatica 55/1 tic rocks of egerian to karpatian age (©imuni∆ & pami∆, 1993). the only published data on volcanic rocks from moæenec area are from ki©pati∆ (1909), who presumed the same age for these rocks as for those from the jesenje area. the tuffs in the kalnik area, are, according to the unpublished fieldtrip guidebook3, of badenian age. investigated samples are listed in the lower part of table 3 on the basis of sampling locality, successively from the west to the east. the chemical composition of the rocks was determined on an arl 8410 x-ray fluorescence (xrf) wavelength dispersive spectrometer equipped with an rh-tube. glass beads, for the determination of major elements, were prepared by melting a 1:1:4 mixture of water-free sample, li2b4o7 and libo2. measured intensities were corrected for matrix effect using the empirical model of lachance & traill (1966). h2o was determined as loss of weight after 4 hr of drying at 110°c, while loss on ignition at 1025°c was taken as h2o +. trace elements were analysed on pressed powder pellets. details on the measuring conditions are given in tiblja© (1996). results of the chemical analyses can be obtained from the authors on request. the computer programme statistica (statsoft, 1995) was used to carry out the discriminant function analysis of the collected data. additional input data (element concentrations and geological age of the rocks) for the analysis were taken from pami∆ (1997). it was necessary to take logarithmic values of element concentrations, except in the cases of gallium and thorium, to achieve a normal distribution of the input data, which is one of the assumptions of discriminant function analysis. all statistically analysed samples are listed in table 3. the first 25 samples are from pami∆ (1997). they are marked with symbols of the type e7 where letter designates age, i.e. e is for egerian eggenburgian, while the numbers correspond to the sample numbers in the tables, in his book, that contain chemical compositions of the rocks of the age concerned. due to the fact that, according to their major elements, as well as immobile trace element content, the investigated volcaniclastic rocks are mainly acid and rarely neutral (tiblja© et al., 2000) only data for the rocks that contain >55wt. % sio2 were considered. rocks of known age were assigned to three age groups ( e g e r i an eggenburgian, karpatian and badenian) and we tried to statistically distinguish these groups on the basis of rock geochemical characteristics, and finally, to assign each newly analysed sample of unknown age to one of these predefined groups. due to the scarce available age data for the volcaniclastic rocks from ©aπa, lapornica, ©eprun, moæenec and kalnik areas their age was taken as unknown. the reason why we considered only three, instead of the four age groups described by pami∆ (1997), was that post-badenian rocks are basic, while, as already mentioned, investigat ed volcaniclastic rocks are acid to neutral. 3. results standardised coefficients for two discriminant functions obtained by discriminant analysis of miocene volcaniclastic rocks, based on their trace element content, are given in table 1 together with their eigenvalues and relative and cumulative proportion of variance extracted by each function. the plot of discriminant scores given in fig. 2 differentiates between rocks of three different ages. function 1 explains 80.8 % variation of the data, with a high negative loading of ce and positive of cu fig. 1 location map of investigated area. circles represent sampling locations of volcaniclastic rocks. 3 ©imuni∆, a. (1981): vodië ekskurzije kroz kalniëko gorje i sjeverozapadni dio dravske depresije.unpublished (in croatian), croatian geological society, zagreb, 25 p. and nd, and differentiates clearly between karpatian samples and the egerian eggenburgian ones, while the badenian samples are transitional. the second function, of bipolar nature, that separates the badenian samples from the karpatian and egerian eggenburgian ones, has a high negative loading of cr and positive of v. coefficients (ce = ai, cr = bi, cu = ci, ..., zr = mi) as well as constant (c) of classification functions of a form si = aix1 + bix2 + cix3 + ... + mixm + c (1) where x1, x2, x3, ..., xm are concentrations, or their logarithms, of elements in the sample, are given in table 2. on the basis of classification scores si each sample was 41tibljaπ, lopariê & belak: discriminant function analysis of miocene volcaniclastic rocks... fig. 2 plot of discriminant scores along function 1 versus function 2, to discriminate volcanic and volcaniclastic rocks of different age (e = egerian eggenburgian, k = karpatian, b = badenian). discriminant function 1 2 log ce -1.77543 0.1676 log co -0.0309 -0.50112 log cr -0.54651 -1.05168 log cu 1.08006 0.71779 ga 0.37776 -0.42432 log la 0.22753 0.05975 log nb 0.3213 0.38883 log nd 0.86753 -0.09416 log ni -0.3365 0.36198 log pb 0.11063 -0.2135 log rb 0.56435 0.48088 log sc -0.02668 0.25888 th 0.07007 0.56928 log v -0.60661 1.01681 log y -0.01791 0.38464 log zn -0.24478 -0.42836 log zr -0.26779 0.05888 eigenvalue 6.12012 1.45174 % of variance relative 80.83 19.17 % of variance cumulative 80.83 100.00 table 1 standardized discriminant function coefficients and related statistics. egerian karpatian badenian eggenburgian log ce 449.13 558.69 492.772 log co -7.368 -8.292 -3.27 log cr -68.481 -64.002 -61.06 log cu -83.598 -103.009 -98.541 ga 4.286 3.105 4.272 log la 56.803 50.776 53.417 log nb -61.637 -70.962 -71.916 log nd -62.86 -76.376 -68.161 log ni 18.139 22.8 18.269 log pb -52.843 -57.491 -51.8 log rb -65.926 -78.378 -76.845 log sc -54.203 -53.004 -55.712 th 0.023 0.056 -0.450 log v 211.827 225.997 209.631 log y -48.405 -45.449 -53.705 log zn -14.858 -11.073 -9.158 log zr 418.166 434.039 423.642 constant -746.471 -918.402 -781.051 table 2 classification function coefficients used in formula (1) for grouping of volcaniclastic rocks according to their age. 42 geologia croatica 55/1 included in the age group for which the score was highest (table 3). the age attributed to the samples on the basis of references mentioned in the previous section is given in the second column of the table. the following three columns contains ages ascribed on the basis of discriminant analysis, ordered into the first, second, and third choice according to the posterior classification probabilities. these classification functions could be used for the classification of samples of unknown age if their chemical composition is known. table 4 gives a comparison between the actual and predicted number of samples in each age group. according to these results 96.5 % of samples have been classified correctly to their pre-defined groups. misclassified samples are due to overlap in the discriminant space of badenian samples with the karpatian ones on one side, and egerian e g g e n b u r g i a n on the other (fig. 2). 4. discussion the results of performed discriminant function analysis, presented in tables 3 & 4 and fig. 2, showed that miocene volcanic rocks of different ages (egerian e g g e nburgian, karpatian and badenian) could be confidently distinguished on the basis of their geochemical data. almost all (55) of the 57 samples of known age, that were used as input data for the analysis, were classified correctly. this analysis showed that karpatian samples could be successfully differentiated from egerian eggenburgian ones. a slight overlap of badenian samples with karpatian and egerian eggenburgian ones is in agreement with the conclusion of pami∆ (1997) that e g e r i an eggenburgian and badenian rocks have similar geochemical characteristics. but in spite of that their discrimination could be performed quite successfully. the high negative loading of ce on discriminant function 1, that successfully discriminates the karpatian samples is in accordance with the elevated ce content of karpatian volcanics (pami∆, 1997). pami∆ (op. cit.) also noticed that karpatian rocks have higher contents of zr, nb and la, and lower sc and y than other tertiary rocks, but this is not obvious from standardised coefficients listed in table 1. these coefficients indicate a higher cu content in the egerian e g g e n b u r g i a n samples than for the other two groups. badenian samples are discriminated by function 2, in which cr and v carry the main discriminatory potential. as shown in table 3, most of the volcaniclastic rocks from the moæenec and kalnik areas, of previously unknown age, are of egerian eggenburgian age according to discriminant function analysis based on geochemical data. the only exception is the sample from the kalnik area (vhk 500) which is karpatian. such results for the samples from the moæenec area support the conclusions of ki©pati∆ (1909), based on petrographic investigations, about the contemporaneous age of the rocks from the moæenec and jesenje areas. equivocal results for volcaniclastic rocks from kalnik could indicate volcanic activity in both egerian eggenburgian and karpatian times, but such results are probably a consequence of problems encountered during investigations of the chemical composition of any volcaniclastic rock. the original chemical composition of volcaniclastic rocks is a consequence of magma composition, which depends mostly on geotectonic environment, and could be strongly modified by: (1) separation during transport of pyroclastic material from the volcanic vent to place of deposition, (2) alteration and (3) admixing of epiclastic or any other detrital material. because of (3) we excluded from the analysis all of the samples that were an obvious mixture of volcanic and other detrital material. a karpatian age obtained for the sample vhk 500 from the kalnik area is probably the result of separation during transport. this is a sample of crystal tuff (sensu lato), and probably, its modal and, consequently, chemical compositions were strongly modified by processes of separation. the obtained chemical composition is thus probably nonrepresentative for the magma and the result for this sample should be treated cautiously. the egerian eggenburgian age for samples from kalnik is not in accordance with available data from ©imuni∆ (1981)3. we also encountered the problem of modified chemical composition due to alteration, or rather, due to the product of alteration of volcanic glass. all of the samples with authigenic zeolites (clinoptilolite and/or mordenite) have relatively elevated contents of barium and strontium. these higher contents are the result of zeolite selectivity for these elements. therefore we have to exclude these elements from the discriminant model, and the conclusion of pami∆ (1997) that rb/ba and rb/sr contents could differentiate egerian e g g e n b u rgian and badenian rocks could not be confirmed. it is obvious that, for distinguishing volcaniclastic rocks of different age on the basis of geochemistry, it is necessary to know their chemical composition but also their mineral and petrographic composition. the statistical analysis was carried out on a limited number of samples and therefore their results should be taken cautiously and should be tested by further investigation. in addition, the available chemical analyses were occasionally incomplete. also, comparison of the literature and our own data, mainly because of different experimental methods was problematical and should be acknowledged. 5. conclusions the discriminant function analysis of geochemical data, which was carried out on a relatively limited number of samples of miocene volcanic rocks from the sava-drava interfluve, enabled the following preliminary conclusions to be made. 43tibljaπ, lopariê & belak: discriminant function analysis of miocene volcaniclastic rocks... sample (locality) age according to age according to discriminant function analysis literature data probability 1 2 3 e7 e e b k e8 e e b k e9 e e b k e11 e e b k e18* e b e k e19 e e b k e20 e e b k k1 k k b e k3 k k b e k4 k k b e k7 k k b e k12 k k b e k15 k k b e k17 k k b e k20 k k b e b9 b b e k b25 b b e k b31 b b e k b35 b b e k b36 b b e k b40 b b e k b42 b b k e b43 b b e k b46* b k b e b51 b b e k krem (poljanska luka) b b e k siva (poljanska luka) b b e k t-6-94-4b (cerovec) e e b k t-5-93-17 (trliëno) e e b k t-5-93-21 (hromec) e e b k t-5-93-18 (hromec) e e b k t-6-93-17e (donje jesenje) e e b k t-7-90-k2 (donje jesenje) e e b k t-790-k5 (donje jesenje) e e b k t-7-90-k18 (donje jesenje) e e b k t-7-90-k22 (donje jesenje) e e b k t-7-90-k27 (donje jesenje) e e b k t-7-90-k27g (donje jesenje) e e b k t-7-90-15 (donje jesenje) e e b k t-7-90-30 (gornje jesenje) e e b k t-7-90-33 (gornje jesenje) e e b k t-4-98-1 (gornje jesenje) e e b k t-7-90-2 (cerje jesensko) e e b k t-7-90-4b (cerje jesensko) e e b k t-7-90-7 (cerje jesensko) e e b k t-7-90-8 (cerje jesensko) e e b k t-7-90-57 (jamno) e e b k t-7-90-62 (jamno) e e b k t-6-93-14 (jamno) e e b k lepoglava e e b k t-4-99-8 (vuglovec) e e b k t-4-99-9 (vuglovec) e e b k t-4-99-10 (vuglovec) e e b k t-4-99-11 (vuglovec) e e b k podrute e e b k hmpm7110 (jesenje) e b k t-7-90-©1 (©aπa) e b k t-3-90-1 (lapornica) e b k ©eprun3 e b k hmpm7113 (moæenec) e b k hmpm7115 (moæenec) e b k t-4-99-3 (moæenec) e b k t-4-99-7 (moæenec) e b k t-4-99-5s (moæenec) e b k t-4-99-2a (moæenec) e b k t-4-99-4 (moæenec) e b k vhk500 (kalnik drenovec) k b e t-5-99-1 (kalnik knezov jarak) e b k kalnik (knezov jarak) e b k vhk227 (kalnik knezov jarak) e b k table 3 classification of samples on the basis of discriminant function analysis. e = egerian-eggenburgian, k = karpatian, b = badenian. incorrect classifications are marked with *. samples from pami∆ (1997) are listed at the top, followed by newly analysed samples of known age, and finally by newly analysed samples of unknown age. 44 geologia croatica 55/1 1) it is possible to obtain an indication about the age of miocene volcanic and volcaniclastic rocks on the basis of their chemical composition. 2) most of the investigated volcaniclastic rocks from moæenec and kalnik areas, whose age was unknown, are, according to discriminant function analysis of egerian eggenburgian age. it must be stressed that such conclusions are only preliminary and should be confirmed or refuted by further investigations on more samples. acknowledgements we are grateful to marta crnjakovi∆ for rock specimens from croatian natural history museum, to josip halami∆, franjo percela and emil bukvi∆ for help during sampling, and to slobodan miko for his help in statistical analysis. we are indebted to anonymous referee for comments that greatly improved the manuscript. thanks also go to julie robson for language editing. the study has been financially supported by the ministry of science and technology of the republic of croatia (project 119304). 6. references ani»i∆, b. & juri©a, m. (1985): osnovna geoloπka karta sfrj 1:100.000. tolmaë za list rogatec l 33-68 (basic geological map, geology of the rogatec sheet).geol. zavod ljubljana in geol. zavod zagreb (1983), zvezni geol. zavod beograd, beograd, 73 p. davis, j.c. (1986): statistics and data analysis in geology.john wiley and sons, new york, 646 p. ki©pati∆, m. (1909): dacit od moædjenca kod novog marofa (dacit von moædjenec bei novi marof in kroatien).rad jazu, 179, matematiëko-prirodoslovni razred, 46, 63-67, zagreb. lachance, g.r. & traill, r.j. (1966): practical solution to the matrix problem in x-ray analysis.canadian spectroscopy, 11, 43-48. pami∆, j. (1997): vulkanske stijene savsko-dravskog meurijeëja i baranje (hrvatska) (volcanic rocks from the sava-drava interfluve and baranja in the south pannonian basin (croatia)).nafta, zagreb, viii+192 p. statsoft (1995): statistica for windows.computer application, statsoft inc., tulsa. ©imuni∆, a. & pami∆, j. (1993): geology and petrology of egerian eggenburgian andesites from the easternmost parts of the periadriatic zone in hrvatsko zagorje (croatia).acta geologica hungarica, 36, 315-330. ©imuni∆, a., pikija, m. & he»imovi∆, i. (1981): osnovna geoloπka karta sfrj 1:100.000. tumaë za list varaædin l 33-69 (basic geological map, geology of the sheet varaædin).geol. zavod zagreb (1982), sav. geol. zavod beograd, beograd, 75 p. tiblja©, d. (1996): zeoliti i drugi produkti alteracijskih procesa u oligocenskim i donje miocenskim piroklastitima na πirem podruëju macelja.unpubl. ph.d. thesis (in croat.), faculty of science, university of zagreb, 167 p. tiblja©, d., lopari∆, v., balen, d., belak, m., crnjakovi∆, m. & halami∆, j. (2000): geokemijske i mineraloπke karakteristike miocenskih vulkanoklastita sjeverozapadne hrvatske (geochemical and mineralogical characteristics of miocene volcaniclastic rocks from the north-western croatia).in: vlahovi∆, i. & biondi∆, r. (eds.): 2. hrvatski geoloπki kongres (second croatian geological congress), zbornik radova (proceedings), cavtat dubrovnik, 429-431, zagreb. manuscript received february 12, 2001. revised manuscript accepted may 20, 2002. percent correct e k b e 97.3 36 0 1 k 100.0 0 8 0 b 91.7 0 1 11 total 96.5 36 9 12 table 4 classification matrix; rows contains number of samples in each observed group while in columns number of samples in predicted groups are given. 1-18-boukhary-343.pdf 1 � mohamed boukhary1, abbas kenawy2 and rafaat basta3 ab stra ct seven larger foraminiferal species: nummulites aff. nemkovi schaub, 1966, nummulites partschi de la harpe, 1880, nummulites bassiounii boukhary & blondeau, 1991, nummulites cf. campesinus schaub, 1966, assilina aff. major heim, 1908, decrouezina aegyptiaca boukhary, 1994 and operculina sp. are described from the early eocene gebel umm russeies, northern galala, eastern desert, egypt. these taxa are biostratigraphically evaluated and according to the standard shallow benthic zones, the identifi ed biozones span sbz 10 to sbz 12 in the shallow benthic zones (sbz) of serra-kiel et al. (1998) which are assigned to the late ypresian. keywords: nummulites, operculina, gebel umm russeies, el galala el bahariya, ypresian, egypt 1 department of geology, faculty of science, ain shams university, 11566 cairo, egypt; (moboukhary@yahoo.com) 2* department of geology, faculty of science, assiut university, assiut, egypt 3 the geological survey of egypt (rgsma), abbasia, cairo, egypt early eocene nummulitids from gebel umm russeies, el galala el bahariya, eastern desert, egypt geologia croatica 62/1 1–18 6 figs. 4 tabs. 6 pls. zagreb 2009 geologia croaticageologia croatica � 1. introduction el galala el bahariya is a high fl at topped plateau located be tween latitudes 28°50’ n and 29°45’ n and longitudes 31°40’ e and 32°30’ e and is one of the most impressive topographical features in the northern part of the north eastern desert. the plateau overlooks the gulf of suez rising 977 m above sea level at gebel umm russeies, and extends between 50 km south of suez city in the north and wadi araba in the south, a distance of about 60 km. inland, the plateau stretches westwards where it merges into the mokattam plateau overlooking cairo in the west. the el galala el bahariya plateau is cut by some wadis, but the main tributaries from west to east are: wadi el qena, wadi el ghul, wadi el-khafouri, wadi abu diaba, wadi ogila, el wadi el-abyad, wadi naoz, wadi umm russeies and wadi haroz (fig. 1). the studied area lies at the far north and east sides of el galala el bahariya, between latitudes 29°30’ n and 29°40’ n and longitudes 32°07’ e and 32°25’ e. near the north eastern part of the el galala plateau, at khashm el-galala, wadi haroz and wadi umm russeies, the lower part of the scarp is composed of lower cretaceous variegated sandstone and marl (malha formation), overlain by a thick series of marly limestone, marl and a thick band of dolomite of late cretaceous age (galala formation). the following turonian fossiliferous dolomite and conglomeratic beds (umm russeies formation) are exposed and, with thickness overlain by marly limestone and shale of palaeocene age (esna shale). these rocks are capped by eocene carbonates rocks which are completely dolomitic in the east and gradually change westward to dolomitic limestone. to the west of wadi naoz, eocene limestones form the foot of the scarp, palaeocene and cretaceous strata never crop out again west of wadi naoz. the general dip of the strata is towards the west and varies from 8° to 10°. el galala el bahariya was affected by tectonic movements which took place during the late cretaceous, the early eocene and the neogene. the dominating faults trend east– west, especially in the northernmost part, but other trends nw–se (gulf of suez) and ne–sw are not uncommon. * in the memory of the late professor abbas kenawy geologia croatica geologia croatica 62/1 2 many faults along the northern face of north galala are arranged en echelon (fig. 1). el galala el bahariya, like other localities in the northern part of the eastern desert, is affected by volcanic intrusions. sheet basalts can be seen at the top of the plateau, and also at the opening of wadi naoz, wadi umm qena and wadi haroz (fig. 1). as a consequence, the sediments are slightly metamorphosed at the contact and hence marblised limestone and calcite dykes are found at wadi haroz, wadi ghoul and gebel menedra. fi gu re 2: stratigraphic section measur ed at gebel umm russeies (section no. 1). fi gu re 1: geologic map of the study area and location of studied sections. geologia croaticaboukhary et al.: early eocene nummulitids from gebel umm russeies, el galala el bahariya, eastern desert, egypt 3 this study is based on four measured stratigraphic sections (figs. 2–5) representing the exposed eocene succession. a brief description and discussion of the rock units from base to top is as follows: esna shale formation, thebes formation and minia formation. 2.1. the esna shale formation in the study area, the esna shale is composed of thinly bedded marl, marly chalk, grey-greenish to grey shale that unconformably overlies the umm russeies formation (swedan et al., 1991). the base of the esna shale is characterized by the presence of operculina sp. and discocyclina sp. while this paper deals with the study of larger foraminifera, mainly nummulitids, collected from the lower eocene rocks of gebel umm russeies in an attempt to locate their exact stratigraphic position in the frame of the standard shallow benthic zones (sbz of serra-kiel et al., 1998) of the eocene sequence. 2. stratigraphical setting the eocene rocks are widely distributed in egypt, well ex pos ed along the nile valley, sinai peninsula, western desert, and the eastern desert including northern and southern galala. there is great lateral variation in both lithofacies and biofacies. fi gu re 3: stratigraphic section measured at gebel umm russeies (section no. 2). geologia croatica geologia croatica 62/1 4 the morozovella velascoensis and morozovella edgari zones are recorded higher in the sequence. the esna shale disappears in the western part of the study area, east of wadi naoz due to the regional dip. in the eastern part (w. haroz), it consists of thinly bedded marly chalk and has a thickness of 35 m. the esna shale attains a thickness that ranges from 60 m at section 1 to 80 m at section 4. the microfaunal assemblages recorded in this study from the esna shale indicate an ypresian age for this unit. 2.2. the thebes formation the thebes formation was introduced by said (1960) for a massive unit of limestone with fl int bands of ypresian age. the type locality is at gebel gurnah, west of luxor, near the site of the ancient thebes capital of egypt, where it is about 300 m in thickness. the basal beds of this unit are rich in operculina libyca schwager (operculina limestone), whi le the lower part is poor in megafossils, and is massive – thickly bedded with tabular and concretionary fl int bands. the upper part includes several marl beds alternating with nummulitic limestone bands rich in nummulites and megafossils. the micro fossils include nummulites praecursor and n. subramondi, lucina thebaica, conoclypeus delanouei, indicating an early eocene age for this assemblage and formation. snavely et al. (1979) divided the thebes formation in the nile valley into three informal members: lower, middle and upper. the fi rst member (lower member) is a transitional contact with the laminated shales and marls of the esna fi gu re 4: stratigraphic section mea sur ed south west of wadi naoz (section no. 3). geologia croaticaboukhary et al.: early eocene nummulitids from gebel umm russeies, el galala el bahariya, eastern desert, egypt 5 shale formation. it consists of laminated to thinly bedded fi ne grained limestone and chalk with scattered chert nodules. the middle member is 100–125 m thick, thinly bedded chalk with nodular limestone interbeds, rich with large benthonic foraminifera. the upper member reaches a maximum thickness of 50 m at gebel shaghab. it consists of interbeds of oysterlimestone and oyster shell-debris with alveolina limestone. in the study area, sadek (1926) mentioned that the lower eocene in el galala el bahariya composed of clastic sediments in the lower part, whereas its upper part is a carbonate, which is quite different from the nile valley sequence. said (1962, 1990) later stated that the farafra formation in the north and south galala is rich in alveolinid fauna of early eocene age. abdallah et al. (1971) recorded 48 m of sandy dolomitic bands rich in alveolinids, operculines and nummulitids overlying the chalky limestone of the sudr formation at gebel thelmet in the northeastern part of southern galala plateau and named it the southern galala formation scheibner et al. (2002). here, the thebes formation is classifi ed lithological into lower, middle and upper members based on lithological and biological characters, that are as follows: fi gu re 5: stratigraphic section measured south of wadi naoz (section no. 4). geologia croatica geologia croatica 62/1 6 the lower member: this member is composed of whi te to pale white limestone and marl to marly limestone of yellowish white color, slightly hard, with rare chert nodules in the upper part. there are many horizons crammed with nummulites partschi, nummulites aff. nemkovi, small and medium sized orbitolites and small specimens of lucina. the thickness of this horizon ranges from 25 to 40 m and increases towards the western side of the study area. at the base of the thebes formation, alveolines have been found southwest of wadi naoz (sections 3 and 4 respectively). the middle member: this member is composed of a sequence of well bedded, white or cream limestone, with poorly lithifi ed bands of chalky to marly limestone, rich with chert bands and nodules. it is also characterized by the cyclic presence of hard bands of limestone about 30–50 cm thick, and is overlain by thinner (10–15 cm) soft bands of a chalky to marly limestone. the top part is made of chert band; each band attains a thickness of a 5 to 8 cm including nummulites partschi and rare medium to large sized nautilus sp. the thickness of this member ranges from 50–90 m, increasing towards the west. the maximum thickness occurs at wadi ogila (90 m). the upper member: this is represented by massive white to snow white chalky limestone, and massive, hard to moderately hard limestone. near the top, the member contains many bands full of nummulites cf. campesinus schaub, orbitolites sp., bryozoa, pelecypods (lucina sp., vulsella sp. and ostrea sp.), gastropods (natica sp., trochus sp., turritella sp.), and echinoids. the nummulitic limestone member measures about 100, 147, 115 and 132 m at sections 1, 2, 3 and 4 respectively. in the west at wadi oliga the member reaches its maximum thickness 160 m, whereas the thickness of this member is reduced to the east, measuring 80 m at wadi haroz. 2.3. the minia formation in the studied area, the minia formation comformably overlies the thebes formation. it occupies the topmost part of the scarp face of el galala el bahariya as well as outcropping over the surface of the plateau. the formation is well exposed at gebel umm russeies and extends beyond the study area. it also crops out on the western side of wadi naoz. the formation is composed of white to snow white limestone at the base, intercalated with dolomitic limestone in the middle which increases in thickness upwards where it is interbedded with thin beds of limestone and chalky limestone. this part of the section is very rich in larger foraminifera (nummulites), algae and macrofossils. the following species were identifi ed from this part of the formation: nummulites bassiounii boukhary & blondeau, decrouezina aegyptiaca (cuvillier), assilina aff. major heim, orbitolites sp., carolia fi scheri strougo, vulsella crispata fischer, large size turritella sp., natica sp., trochus sp. and pterolucina monosulcata (strougo) and long alveolina cf. frumentiformis. the minia formation yields n. bassiounii, d. aegyptiaca, and a.aff. major. the total thickness of this part of the sequence reaches 150 m in section 2, 90 m in section 3 and 170 m in section 4. 3. biostratigraphy the distribution of the different species of the larger foraminifera mainly (nummulites and operculina) in the studied succession of the studied area had enabled the identifi cation of 4 biostratigraphic zones. these matched well with sbz 10 to sbz 12 of the standard shallow benthic zones of serra-kiel et al. (1998). figure 6 shows the distribution of the larger foraminifera in the studied area and the identifi ed biostratigraphic zones, from top to base, as follows: 4. nummulites bassiounii/decrouezina aegyptiaca/assilina aff. major zone 3. nummulites partschi/nummulites cf.campesinus/n. aff. nemkovi zone 2. nummulites partschi 1. operculina sp. zone fi gu re 6: distribution of larger foraminifera in the study area. geologia croaticaboukhary et al.: early eocene nummulitids from gebel umm russeies, el galala el bahariya, eastern desert, egypt 7 plate 1 1–19 nummulites partschi de la harpe 1–12 sample 22, bed 8, gebel umm russeies (section no. 1); depository 22822–22833. 13–19 sample 30, bed 10, gebel umm russeies (section no. 1); depository 301034–301045. geologia croatica geologia croatica 62/1 8 these bio zones are assigned to the late ypresian following the scheme of schaub (1981) and serra-kiel et al. (1998). depository: the material is deposited in the collection of boukhary, department of geology, faculty of science, ain shams university, egypt. 3.1. the morphological characteristics of nummulitids taxonomy superfamily nummulitacea de blainville, 1827 family nummulitidae de blainville, 1825 genus nummulites lamarck, 1901 type species: nummulites laevigatus (bruguiere) [camerina laevigata, bruguiere, 1792] nummulites partschi group nummulites partschi de la harpe, 1880 (pl. 1, figs. 1–19) 1880 nummulites partschi de la harpe, p. 33, pl. iii/i, fi gs. 1–7(b) 1880 nummulites oosteri de la harpe, pl. 38, pl. iii/ii, fi g. 1–6(a) 1951 nummulites partschi de la harpe – schaub, p. 140, fi g. 12, 159–183; pl. 3, fi g.16–18; pl. 4, fi g. 1–9, 13–15 1981 nummulites partschi de la harpe – schaub, p. 108, fi gs. 80, 87; pl. 28, fi gs. 1–20; pl. 29, fi gs. 1–14, tab. 5/c microspheric form (b-form): form lenticular or fl at, slightly irregular rounded or truncated periphery, granulation visible on the surface especially near the periphery sometimes granules arranged on or between the septal fi laments, surface with radial septal fi lament or curved diameter 6.5– 13.2 mm, thickness 2.8–3.3mm. equatorial section: with the characteristics of the nummu lites partschi group, the septa are inclined, particularly near the outer marginal cord, spire more or less regular and loosly coiled laxer toward the periphery, marginal cord relatively thick and regular, approximately, 1/5th of the height of the whorls, septa straight and slightly curved or inclined, chamber quadrangular in the centre, while isometric in the centre becoming elongated (length greater than height) near the periphery. number of whorls in relation to the radius is as follows: 8 whorls in a radius of 3.5 mm, 9 whorls in a radius of 3.99 mm and 10 to 12 whorls in a radius of 5.6 to 6.72 mm. megalospheric form (a-form): form lenticular more or less infl ated, truncated or rounded pillars arranged around the centre. diamater: 2.5–4.5 mm, thickness: 1.5–2.6 mm, number of whorls v. radius; 3 whorls in a radius of 1.26 mm to 1.54 mm and 4 whorls in a radius of 1.75–1.89 mm. protoconch size ranges from 0.35 mm to 0.49 mm. remarks: our species compares well with nummulites partschi. it differs from n. burdigalensis cantabricus schaub as being much larger and loosly coiled coiling (table 1). nummulites partschi as mentioned in schaub (1981) has a wide distribution in the tethyan province and is a guide species for the ypresian. according to schaub (1981), nummulites partschi lays in the phylogenetic series between nummulites ornatus “upper ilerdian” and nummulites tauricus de la harpe (middle to upper cuisian). stratigraphic distribution: this species is recorded from the thebes formation of all the studied sections. in the stratigraphic section no. 1, it is recorded from beds 8, 10 and 11. in the stratigraphic section 2, the species is recorded from beds 3 and 8. in the stratigraphic section no. 3, the species is recorded from beds 4, 8 and 9 and in the stratigraphic section no. 4 the species occurs in from bed 12. age: late ypresian. table 1: measurements of nummulites partschi (this study) in comparison with nummulites partschi described by schaub (1981). character nummulites partschi (after schaub, 1981) nummulites partschi (this study) diameter a-form 2.2–4.7 mm 2.5–4.5 mm thickness 1.1–2.5 mm 1.5–2.6 mm granulation granules condensed coarse and spirally arranged granules concentrated in the polar region in juveniles, sometimes spirally arranged number of whorls and radius 3–4 whorls in a radius of 0.9–1.4 mm 3 whorls in 1.26–1.54 mm and 4 whorls in a radius of 1.75–1.89 mm protoconch size 0.3–0.6 mm 0.35–0.49 mm diameter b-form 5–13 mm 6.5–13.2 mm thickness 1.8–4.5 mm 2.8–3.3 mm granulation granules on the whole surface of the test granules concentrate only on the polar region number of whorls and radius 11 whorls in a radius of 5–5.3 mm and 13 whorls in a radius of 6 mm 8 whorls in a radius of 3.5 mm, 9 whorls in a radius of 3.99 mm 10–12 whorls in 5.06–6.72 mm geologia croaticaboukhary et al.: early eocene nummulitids from gebel umm russeies, el galala el bahariya, eastern desert, egypt 9 plate 2 1–8 nummulites aff . nemkovi schaub, sample 24, bed 9, gebel umm russeies (section no. 1); depository 2491–24914. geologia croatica geologia croatica 62/1 10 nummulites distans group nummulites aff . nemkovi schaub, 1966 (pl. 2, figs. 1–9) 1961 nummulites nemkovi minor d’archiac, nemkov & barkhatova, p. 63, pl. iv, fi gs. 5–11 1966 nummulites nemkovi schaub sp. nov. – schaub, p. 297, fi g. 2 1981 nummulites nemkovi schaub, 1966, p. 183, fi g. 108; pl. 66, fi gs. 6, 7, 20–31, 36, tab. 12/e microspheric form: (b-form): form lenticular, fl at with polar thickening, or somewhat planar with an undulating periphery, surface more or less smooth. pillar can be seen only within the internal whorls when the external whorls are exfoliated, septal fi laments curved or s-shaped and irregular, marginal cord rather thick. diameter ranges from 17.3 to 18.5 mm and thickness from 2.1 to 2.5 mm. equatorial section: spire and septa are of the same character as the nummulites archiaci-pratti group, the curved and broadly arched number of whorls v. radius is as follows: 13 whorls in a radius of 8.68 mm, 9 and 10 mm and 14 whorls in a radius of 9.60 mm. megalospheric form (a-form): form lenticular, fl at, septal fi laments radial to undulate. a few granules occur around the centre. diameter ranges from 3.8 to 5.5 mm, thickness is 1–1.5 mm. equatorial section: spire and septa exhibit the characteristics of the nummulites archiaci-pratti group, number of whorls v. radius is as follows: 3 whorls in a radius of 1.8 mm, 4 whorls in a radius of 1.8 mm and 5 whorls in a radius of 2.8 mm. protoconch size ranges from 0.5 to 0.57 mm. remarks and differences: nummulites aff. nemkovi is compares and matches well with the description and fi gures given in schaub (1981) except for a small difference in thickness, which seems to be lower in the present material. it is larger than n. haymanensis and smaller than n. kaufman ni and n. distans. stratigraphic distribution: this species is recorded from stratigraphic section no. 1, bed 9 and 4 and in stratigraphic section no. 2, bed 4. age: late ypresian. nummulites burdigalensis group nummulites cf. campesinus schaub, 1966 (pl. 3, figs. 1–14) 1966 nummulites campesinus nov. sp. – schaub (1966a), p. 361, fi gs. 3k–n; fi gs. 4, 5; pl. 1, fi gs. 22–27; pl. ii, fi gs. 1–15 1973 nummulites campesinus schaub – kapellos, p. 77, fi gs. 162–170; pl. 47, fi gs. 1–9; pl. 48, fi gs.1–4 1974 nummulites campesinus schaub – pavlovec in cimerman et al., p. 66 et 20, pl. 17, 18 1976 nummulites campesinus schaub – rahaghi & schaub, p. 773, pl. iii, fi gs. 1–6 1981 nummulites campesinus schaub – schaub, p. 83, fi gs. 72, 74, 81; pl. 7:23–44; pl. 8:1–22; pl. 9:1–20; tab. 2: g, h microspheric form (b-form): test lenticular to fl at, septal radial or s-shape and wrinkled in a few specimens, granulated with granules covering the whole surface of the test. diameter ranges from 5.8 to 9.8 mm, thickness is 1.8–3.1 mm. equatorial section: spire regular, as in the nummulites burdigalensiss group, test lenticular with a more or less round ed periphery, marginal cord rather thick, number of whorls v. radius is as follows: 12 whorls in a radius of 4.3 mm and 13 whorls in a radius of radius 4.6 mm. megalospheric form (a-form): form biconical lenticular thick in the middle of the test; surface with radial septal fi laments or curved with developing granules in the pole. diameter ranges from 2.5–3.6 mm, thickness is 1.0–1.9 mm. equatorial section: spire as in form b is regular with the character of nummulites burdigalensis group. number of whorls v. radius is as follows: 5 whorls in a radius of 1.4– 1.8 mm, protoconch size ranges from 0.25 to 0.35 mm. remarks: nummulites cf. campesinus is a primitive sta ge of n. campesinus schaub; it falls into the lower part of the dimensional range of this species. stratigraphic distribution: several occurrences of this species are recorded from the thebes formation, stratigraphic section no. 1, beds 18 and 19; stratigraphic section no. 2, beds 8, 9 and 10, stratigraphic section no. 3, bed 10, and stratigraphic section no. 4, beds 13 and 14. age: late ypresian. table 2: comparison between nummulites cf. campesinus and nummulites campesinus (measurements from schaub, 1981). character nummulites cf. campesinus schaub (this study) nummulites campesinus schaub (from schaub, 1981) diameter b-form 5.8–9.8 mm 5–12 mm thickness 1.8–3.1 mm 3–5 mm no. or whorls v. radius 12–13 per radius 4.4–4.6 mm 11 whorls in 2.5–4.2 mm and 15 whorls in 2.4 to 4.6 mm granulation granulated granulated diameter a-form 2.5–3.6 mm 4–5 mm thickness 1.0–1.9 mm 2.5 mm no. of whorls v. radius 5 whorls in a radius 1.4–1.8 mm 4–5 whorls in a radius of 1.7–2.0 mm protoconch size 0.25–0.35 mm 0.35–0.45mm geologia croaticaboukhary et al.: early eocene nummulitids from gebel umm russeies, el galala el bahariya, eastern desert, egypt 11 plate 3 1–14 nummulites cf. campesinus schaub, sample 65, bed 14, south of wadi naoz (section no. 4); depository 65141–651414. geologia croatica geologia croatica 62/1 12 nummulites subramondi group lineage of nummulites perplexus schaub, 1981 nummulites bassiounii boukhary & blondeau, 1991 (pl. 4, figs.1–14) 1883 nummulites lucasana obsolete – de la harpe, p. 208, pl. 4, fi gs. 11–14, form-a (non n. obsolete de la harpe, 1877), p. 824, pl. xl, fi gs. 8a, b) 1991 nummulites bassiounii – boukhary & blondeau, p. 23, fi g. 5 (1–9), (with the listed synonymy) microspheric form (b-form): test of medium size, lenticular with truncated subangular margin, granulated in juveniles and non granular in adults as in this generation the granulation is a regressive feature. septal fi laments radial, s-shaped to broadly meandering or wrinkled. diameter rang es from 8.5 mm to 16.2 mm and thickness ranges from 3 to 6 mm. equatorial section: spire regular and the septa are typical of the nummulites subramondi group, curved at the base while perpendicular at the top. number of whorls against the radius: 10–14 whorls in a radius of 5.5–6.25 mm and 15–17 whorls in a radius of 6.30–7.7 mm. megalospheric form (a-form): test small, lenticular to biconical with radial septal fi laments slightly twisted at the pole. a few small granules on the pole are observed. diameter ranges from 3.0 to 4.0 mm, thickness ranges from 1 to 2 mm. number of whorls v. radius: 4 whorls in a radius of 1.7 to 1.89 mm. protoconch diameter ranges from 0.49 to 0.6 mm. remarks: nummulites bassiounii boukhary & blon deau (1991) was believed to be the ancestral form of nummulites perplexus schaub (1981). both of these are related to the nummulites subramondi group. stratigraphic distribution: it occurs in the minia formation stratigraphic section no. 2, from bed 15 and section no. 3 from bed 13. age: late ypresian. genus: assilina d’orbigny, 1839 type species: assilina spira de roissy, 1805 designated by d’archiac & haime, 1853 assilina aff . major heim, 1908 (fig. 5, figs. 1–10) aff. 1908: assilina granulose var. major heim, p. 247, fi g. 24e; pl. 6, fi g. 26 aff. 1963: assilina major heim – schaub, p. 294, fi g. 5 aff. 1963: assilina major schaub – pavlovec, p. 474, fi g. 35 aff. 1966b: assilina major heim – schaub, p. 294, fi g. 1 aff. 1974: assilina major heim – pavlovec in cimerman et al., p. 56; pl. 10–12; pl. 13, fi g. 1 aff. 1976: assilina major heim – rahagi & schaub, p. 799; pl. 7, fi gs. 8–10 microspheric form (b-form): discoidal, slightly undulated and highly granulated near the centre. diameter rang es from 13 to 17 mm, thickness is 1.2–2.2 mm. equatorial section: in keeping with the characteristics of the assilina spira group, the number of whorls for given radius is as follows: 8 whorls in a radius of 7.35 mm, 6.51 mm, and 6.86 mm and 9 whorls in a radius of 7.1 mm and 7.91 mm. megalospheric form (a-form): diameter ranges from 3.5–6.2 mm, thickness is 0.6–1.2. number of whorls per radius is as follows: 3 whorls in a radius between 1.47–2.83 and 5 whorls in a radius of 2.975 mm, 3.08 mm, 2.94 mm, 3.01 mm and 2.94 mm. diameter of protoconch ranges from 0.28 mm to 0.42 mm (table 3). stratigraphic distribution: this species is only record ed only from stratigraphic section no. 2, bed 16. remarks: our species compares well with assilina major of schaub (1981). age: late ypresian. table 3: comparison between assilina major (this study) and assilina major heim, of schaub (1981). character assilina major heim (this study) assilina aff . major heim in schaub, 1981 diameter b-form 13–17 mm 17–26 mm thickness 1.2–2.2 mm 1.2–2.5 mm no. or whorls v. radius 8 whorls in a radius of 6.5–7.0 mm 9 whorls in a radius of 7.1–8.0 mm 10 whorls in a radius of 8.5–11.5 mm 11 whorls in a radius of 10.4–13.0 mm 12 whorls in a radius of 11.9 mm no. of whorls 8–9 whorls 10–12 whorls diameter present present diameter a-form 3.5–6.2 mm 6–10 mm thickness 0.60–1.2 mm 0.8–1.5 mm no. of whorls v. radius 3 whorls in a radius of 1.5–2.5 mm 5 whorls in a radius of 2.9–4.3 mm 5 whorls in a radius of 3.5–5.0 mm 6 whorls in a radius of 4.5–5.5 mm protoconch size 0.28–0.42 mm 0.5–0.9 mm geologia croaticaboukhary et al.: early eocene nummulitids from gebel umm russeies, el galala el bahariya, eastern desert, egypt 13 plate 4 1–14 nummulites bassiounii boukhary & blondeau, sample 47, bed 13, gebel umm russeies; depository 741–7414. geologia croatica geologia croatica 62/1 14 plate 5 1–10 assilina aff . major heim, sample 98, bed. 16 (section no. 2); depository 98161–981610. geologia croaticaboukhary et al.: early eocene nummulitids from gebel umm russeies, el galala el bahariya, eastern desert, egypt 15 plate 6 1–15 operculina sp., sample 2, bed 1, esna shale, gebel umm russeies (section no. 3); depository 211–2115. 16–21 decrouezina aegyptiaca (cuvillier), sample 52, bed 13, southwest of wadi naoz (section no. 3); depository 521316–251321. geologia croatica geologia croatica 62/1 16 ta bl e 4: c om pa ris on b et w ee n n um m ul iti c zo na tio ns in p al eo ge ne o f c rim ea w ith th os e in g al al a pl at ea u eg yp t, (a ft er k a pe ll o s, 1 97 3) . geologia croaticaboukhary et al.: early eocene nummulitids from gebel umm russeies, el galala el bahariya, eastern desert, egypt 17 genus decrouezina boukhary, 1994 decrouezina aegyptiaca (cuvillier, 1930) (pl. 6, figs. 16–21) 1883 operculina cf. canalifera d’archiac – schwager, p. 144, pl. 19, fi g. 3 1930 assilina praespira douville var. aegyptiaca cuvillier, p. 139, pl. 13, fi g. 4 1990 operculina praespira var. aegyptiaca cuvillier – strougo et al., p. 64 1994 decrouezina aegyptiaca cuvillier – boukhary, p. 97, pl. 1, fi gs. 1–7 microspheric form (b-form): test fl at with central swelling. test of medium size, assilinoid in shape with thick marginal cord. test evolute except for the central part (about 3 whorls) which is involute. diameter is up to 25 mm, 5–6 whorls in 12 mm. megalospheric form (a-form): test small and fl at, diameter ranges from 3.7 to 5.5 mm; protoconch ranges from 0.35 to 0.42 mm. remaks: decrouezina (type-species: assilina praespira var. aegyptiaca cuvillier, 1930) was believed by boukhary (1994) as the descendant taxon of ranikothalia, for the presence of common characters between both, such as the thick marginal cord, presence of plexus marginalis. the phylogeny of this group of taxa is from tight open. stratigraphic distribution: this species occurs in gebel umm russeies in stratigraphic section no. 3, bed 13. age: late ypresian. operculina sp. (pl. 6, figs. 1–15) microspheric form (b-form): test fl at loose spire with a rather thick marginal cord. test granulated and granulation concentrated in the central part of the test. septa in the last whorl are upright, oblique in the fi rst part. chambers are high and narrow. diameter 2.38 to 5.6 mm, thickness: 0.84 to 1.12 mm. megalospheric form (a-form): test small, in axial section the fi rst and second chambers are rounded, isolepidine, the middle part is triangular. in equatorial section the septa are perpendicular at the base while arched at the top. diameter: 0.63 to 1.62 mm, thickness: 0.21 to 0.77 mm. protoconch ranges from 0.12 to 0.17 mm. stratigraphic distribution: operculina sp. is recorded from the esna shale, stratigraphic section no. 3, bed 1. age: late ypresian. table 4 shows the comparison between the biozones recorded from gebel umm russeies, and northern galala with those recorded from the palaeogene of the crimea after (kapellos, 1973), and the standard shallow benthic zones (sbz) identifi ed by serra-kiel et. al., 1998. 4. conclusions at gebel umm russeies, the ypresian sediments unconformably overlie upper cretaceous rock; the palaeocene is completely missing. however, at wadi naot (northern galala) a nearby section to the gebel umm russeies study area, the palaeocene section is well represented between the upper cretaceous and the ypresian units. further north in the gebel ataqa area, the palaeocene is also missing (osman, 2003). in the southern galala plateau where the lower eocene rocks are exposed, the following foraminifera have been observed: nummulites praeatacicus, n. saharaensis and bassiounina sanctipauli (boukhary et al., 1998). at gebel umm russeies this assemblage is missing, instead the microfauna here includes ?operculina sp. the different faunas in the two locations belong to the same time (early ypresian), yet the conditions of deposition varied greatly from a reefal shallow environment in the south hence the fl ourishing of nummulites to an open platform in the north where these fossils are replaced by ?operculina. the gebel umm russeies area seems to have been uplifted after the upper cretaceous sediments namely the adabiya formation were deposited (el akkad & abdallah, 1971) for the whole of the palaeocene. to the south, the blocks were submerged during this time span hence palaeocene sediments were deposited. over many blocks in both the northern and southern galala, the sedimentary basin became more shallow because of infi lling by these sediments, hence the environment of deposition of the next sediment (early ypresian, esna shale) includes shallow marine fauna i.e. nummulites spp. in contrast, at the gebel umm russeies section, the platform was relatively deeply drowned and a different fauna (operculina sp.) fl ourished. the thebes formation (ypresian) covers a huge stretch of egypt to the latitude of 22° 40’ in the south. an extensive tethyian transgression during the ypresian was recorded over many parts of egypt. marine waters transgressed over the gulf of suez blocks regardless of their locations. all the blocks are capped by lower eocene rocks, representing different environmental conditions, but all belonging to the ypresian. at gebel umm russeies, the thebes formation is represented by carbonate beds, partly marly, chalky and dolomitic. nodular limestones are common – whereas oolites are of limited occurrence. acknowledgement the authors deeply thank prof. bahay issawi, prof. of stratigraphy (ex in the geological survey of egypt) for his revision of the manuscript. acknowledgements are extended to prof. mohamed el amin bassiouni (ain shams university) for his valuable comments during the progress of the work. the authors are grateful to prof. jochen kuss (bremen university) for critically revising the manuscript. deep gratitude goes to the two reviewers prof. cesare papazzoni and danielle decrouez for their review of the manuscript which improved it substantially. many thanks to prof. amin strougo (ain shams university) for his help in the fi eld work. references abdallah, a.m., el-sharkawi, m.a. & marzouk, a. (1971): geology of the mersa thelmet area, southern galala, eastern desert, a.r.e.– bull. fac. sci., cairo univ., 44, 271–280. geologia croatica geologia croatica 62/1 18 amer, a.f., kristsoy, m.f. & hanna, f.l. (1970): the egyptian carbonate rocks and possibilities of their utilization in o. maharam et al. ed.– studies on some mineral deposits of egypt: g.s.e., cairo, 183 p. bahr, s. (1991): stratigraphy of the palaeogene succession of jabal hafi t, a – ain, uae.– unpublished ph.d. thesis, ain shams university, cairo, 183 p. berggren, w.a. (1971): tertiary boundaries and correlations.– in: the micropaleontology of oceans. proc. symp. (cambridge, sept. 10–17, 1971), 693–809. boukhary, m. (1994): decrouezina n.gen: descendant of ranikothalia in nummulitacea.– micropaleont., 40/1, 95–99. boukhary, m.a., abdallah, a.y. (1982): stratigraphy and microfacies of the eocene limestones at beni hassan, nile valley, egypt.– n. jb. geol. palaeont., mh., 151–152. boukhary, m., kulbrok, f. & kuss, j. (1998): new nummulitids from lower eocene limestones of egypt (monastery of st. paul, eastern desert).– micropaleont., 44/1, 99–108. boukhary, m.a. & blondeau, a. (1991): nummulites bassiounii n.sp (n. perplexus lineage) of late cretaceous from beni hassan, nile valley, egypt.– n. jb. geol. palaont. mh., 1, 21–30. cimerman, r., pavlovec, j., pavšic, j. & todesco, l. (1974): biostratigraphy of the palaeogene beds of goriska brda: macroforaminifera.– geologija, 17, 115–130. cuvillier, j. (1930): revision du nummulitique egyptien stratigraphie et paleontology.– int. egypt. mem., 16, 371. el-akkad, s. & abdallah, a.m. (1971): contribution to geology of gebel ataqa area.– annals of the geological survey of egypt. 1, 21–42. harpe, de.la. (1883a): etude des nummulites de la suisse et revision des espèces éocènes des genres nummulites et assilina.– mem. soc. paleont. suisse, 10, 141–180. harpe, de.la. (1883b): monographie der aegypten und der libyschen wüste vorkommenden nummuliten.– palaeontogr., 30, 155– 216. harpe, de.la. (1880): notes sur les nummulites partschi et oosteri de la harpe du calcaire du michelsberg,pres stockerau (autriche) et du gurnigel-sandstein de suisse.– bull. soc. vaud. sci. nat., 18 (84), 33–40. heim, arn. (1908): die nummuliten – und flyschbildungen der schwei zeralpen. versuch zu einer revision der alpinen eocaenstratigraphie.– abh. schweiz. paläont. ges., 35, 1–301. hottinger, l. & schaub, h. (1964a): les séries paléontgènes de quelques basins méditerraneens, colloque paléogène bordeaux.– mem. b.r.g.m., 28, 611–625. hottinger, l. & schaub, h. (1964b): le synchronisme des biozones basé sur les nummulites, assilines et alvéolines, colloque paléogène bordeaux.– mem. b.r.g.m., 28, 25–629. hottinger, l. (1977): foraminiferes operculiniformes.– mem mus. nat. 6, hist. nat., xl., 40, paris, 160 p. kapellos, c. (1973): biostratigraphie des gurnigelfl ysches mit besonderer beruschsichtigung der nummuliten und des nannoplanktons unter einbeziehung des paläogenen nannoplanktons der krim (u.d.s.s.r.).– mém. suisse paleont., 96, 1–128. nemkov, g.i. & barkhatova, n.n. (1961): nummuliten, assilinen und operculinen der krim [in russian].– isdat. akad. nauk. sssr, 1–125. osman, r.a. (2003): new fi ndings in the eocene stratigraphy of gebel ataqa-northern galala, north eastern desert, egypt.– sedimentology of egypt, 11, 95–109. rahaghi, a. & schaub, h. (1976): nummulites et assilines du ne de l’iran.– eclogae geol. helv., 69, 765–782. sadek, h. (1926): the geography and geology of the district between gebel ataqa and el-galala el-bahariya (gulf of suez).– geol. surv. egypt. paper, 40, 120 p. said, r. (1960): planktonic foraminifera from thebes formation, luxor, egypt.– micropaleont., 6, 277–286. said, r. (1962): the geology of egypt.– elsevier, 377 p. said, r. (1990): the geology of egypt.– balkema, rotterdam, 734 p. schaub, h. (1951): stratigraphie und paleontologie des schlierenfl ysches mit besonderer berucksichtigung der paleovaenen und untereocaenen nummuliten und assilinen.– schweiz., paleont. abh. (mem. suisse paleont.), 68, 1–222. schaub, h. (1966): uber die grossforaminiferen in untereocaen von campa (ober-aragonien).– eclogae geol. helv., 59, 335–377. schaub, h. (1981): nummulites et assilines de la tethys palaeogene, taxinomie, phylogenese et biostratigraphie.– mem. schweiz. palaontol. abhandlungen, 104, 236 p. atlas i: vol. 105 & atlas ii: vol. 106. schwager, c. (1883): die foraminifereren aus den eocaenablagerungen der libyschen wüste und aegyptens.– paleontogr., 30, p. 79–153. serra-kiel, j., hottinger, l., caus, e., drobne, k., ferrandez, c., jauhri, a.k., less, g., pavlovec, r., pignatti, j., samso, j.m., schaub, h., sirel, e., strougo, a., tambareau, y., tosquella, j. & zakrevskaya, e. (1998): larger foraminiferal biostratigraphy of the tethyan palaeocene and eocene.– bull. soc. geol. france, 169/2, 281–299. snavely, p.o., garrison, r.e. & meguid, a.a. (1979): stratigraphy and regional depositional history of the thebes formation (lower eocene), egypt.– annals of geological survey of egypt, 9, 344–362. swedan, a.a., ibrahim & kandel, a. (1991): back to the future el ramiya formation and rewriting the libyan mokattamian stratigraphy of gabal ataqa and gabal el goza el hamra.– ann. geol. surv. egypt., 17, 193–198. strougo, a., bignot, g., boukhary, m. & blondeau, a. (1990): the upper lybian (possibly ypresian) carbonate platform in the nile valley, egypt biostratigraphic problems and palaeoenvironments.– rev. micropaleont., 33/1, 54–71. wade, m.e. (1964): nannofossils from the palaeogene of the south western ussr. unpubl. msc thesis, urbana. ill: university of illinois, college of liberal arts and sciences, 52 p. manuscript received january 2, 2008 revised manuscript accepted may 5, 2008 biondic.indd 195 �ab stra ct the plitvice lakes national park, founded in 1949, is located in the central part of the dinaric karst region in croatia. large karst springs and 16 lakes separated by tufa barriers and waterfalls are the fundamental natural phenomenon of the national park, which has a million visitors a year. lakes are recharged by water from the mountainous region of lika, and the runoff is directed towards the black sea catchment. the whole area of the national park is composed of carbonate rocks with different levels of natural permeability and very complex tectonic relationships, which allowed discharge of groundwater, maintaining the lake and fi nally partial loss of water to the karst underground after passing through the lake system. prošćansko and kozjak are the two largest lakes which dominate and by their internal dynamics ensure maintenance of the high water quality of the whole system. a conceptual hydrogeological model of the plitvice lakes was the result of complex research in the framework of international cooperation between the university of zagreb and the joanneum research institute in graz. the research identifi ed completely new data about the genesis of the water system, the hydrogeological characteristics of the karst water catchment, the dynamics of the water in the lakes, locations of water loss from the plitvice lakes system, the “hanging” position of lake kozjak in relation to groundwater and a whole range of other data important for the preservation and protection of water resources in the national park. throughout the project were made 3022 measurements of different physicochemical parameters, 7885 of the chemical analysis of water and 1082 analysis of stable isotopes. keywords: national park plitvice lakes, conceptual hydrogeological model, hydrogeochemical analyses, water quality, lake dynamics, lake sustainability the conceptual hydrogeological model of the plitvice lakes � božidar biondić, ranko biondić and hrvoje meaški faculty of geotechnical engineering, university of zagreb, hallerova aleja 7, 42000 varaždin, croatia; (bbiondic@usa.net; rbiondic@gfv.hr; hmeaski@yahoo.com) doi: 104154/gc.2010.17 geologia croatica 63/2 195–206 16 figs. 1 tab. zagreb 2010 geologia croaticageologia croatica 1. introduction the plitvice lakes national park is located in the central part of the dinaric karst area in croatia (fig. 1). many nature lovers and researchers at the end of the 19th and in the early 20th century had already noticed this naturally attractive area with water, karst forms, forests and biodiversity. the plitvice lakes water system consists of 16 lakes separated by tufa barriers, differing in altitude by 160 m over a length of 8.2 km (fig. 2). the plitvice lakes were proclaimed as a national park in 1949 and by 1979 had entered the unesco world heritage list. water resources, and sediments formed by water (tufa), are the fundamental natural phenomena of the park because all other natural resources (fl ora, fauna, aquatic ecosystems), largely depend on maintaining the water quality and water balance. the basic question of the research project was “how to ensure the sustainability of water resources and assess the visitor capacity of the park’’. this is an important issue because the number of visitors is approaching one million a year, with daily numbers during weekends of the tourist season reaching over ten thousand. all visitors are generally retained in the narrow area of the lakes and the loads are excessive at times. there are three basic objectives of the project: (1) protection of the catchment area of the huge karst springs, which discharges most of the water for the lakes, (2) geologia croatica 63/2geologia croatica 196 protection of the lakes and waterfalls overloaded by numerous visitors and tourist facilities and (3) the broader protection of the karst environment from the impact of the national park (biondić et al., 2008). the plitvice lakes are fed by waters of the three biggest karst springs – the black river, the white river, and the plitvice springs. the river korana, which belongs to the danube basin, originates from the plitvice lakes system. the main characteristic of the korana river downstream from the plitvice lakes is a gradual but steady loss of water along the river bed and during summer dry periods the river remains completely without water from about 1 km downstream of the spring zone. climatic conditions in the catchment of the plitvice lakes are typically mountainous; continental with an average annual rainfall between 1128 and 2113 mm. the upper fi gu re 1: schematic hydrogeological map of the plitvice lakes catchment area. fi gu re 2: schematic hydrogeological cross-section of the plitvice lakes water resource system. biondić et al.: the conceptual hydrogeological model of the plitvice lakes geologia croatica 197 enon. after groundwater discharge, fl ow occurs to longitudinal faults on the north-eastern side of the largest lake kozjak without any losses. after this line, there is a gradual loss of water from the system, which eventually results in the complete drying up of the korana river about a kilometre downstream from the plitvice lakes. the hydrological interpretation of the plitvice lakes basin was based on gauge station measurements in the national park, on the korana river (taken by the state hydrometeorological institute) and data from published papers (zwick er & rubinić, 2005, zwicker et al., 2006; ridjanović, 1976). most of the plitvice lakes water fl ows from karst springs, including the black river (75%) and the white river (25%). the mean annual infl ow into the lake is 2.14 m3/s, with a maximum of 11.60 m3/s and a minimum of 0.6 m3/s. all this water fl ows through the falls and the upper lakes, draining into lake kozjak. the largest lake, kozjak receives on average, an additional 24% of water from the immediate catchment compared to fl ows from the upper lakes. direct infl ow quantities in the mean annual fl ow rate are 0.67 m3/s, (maximum 3.4 m3/s and minimum 0.2 m3/s). these data show that the fl ows into the upper lakes through the large karst catchment in a mountain area are far greater than direct fl ows into lake kozjak with a far smaller basin and mainly surface runoff. the plitvica watercourse fl ows into the plitvice lakes system via the highest waterfall in the national park in the spring area of the korana river. water fl ow from the plitvica stream reaches a maximum of 5.92 m3/s, while in average fl ow conditions it is 0.58 m3/s, and the measured minimum is only 0.03 m3/s. the measured data show that at high and medium water fl ow rates, water losses from the system are not obvious, but at low water even small losses from the system are evident. thus, for example, in lake kozjak, which does not suffer major water loss, a defi cit is incurred by the exploitation of water for the water supply (60 l/s), which is evident and measurable. however, the plitvica watercourse has large problems with water, as during the summer dry period, almost nine tenths of the total amount of water is lost through sinks along the riverbed. this reduces the attractiveness of the largest waterfall in the park during the peak visiting period in the summer months. increasing water losses occur along the river korana, so that during summer dry periods, the river completely dries out from about 1 km downstream of the spring zone. at next 10 km from the spring zone, the river bed is completely without water for more than 4 months of the year. analysis of many years worth of hydrological data shows that water loses from the korana river are about 0.85 m3/s on average, lower during high water (~ 0.6 m3/s), due to saturation of the karst underground and higher in the summer dry periods (~ 1.15 m3/s). according babinka (2007) the total volume of the lakes is 22.95 x 106 m3 and this was the basis for calculating the average water fl ow through the cascade system of the lakes over about 3 months. this calculation did not take into account the seasonal stratifi cation of the lakes kozjak and prošćansko, which signifi cantly extends the average length of water retention in the plitvice lake system. part of the korana river, downstream of the lakes, has the characteristics of torrential fl ow as a result of the concentration of rainfall in the autumn and spring periods. this is particularly pronounced in the springtime, when snow melt overlaps with more extensive precipitation. average annual air temperature range from 8.9–10.4°c and the wind is predominantly of north-eastern directions. 2. hydrogeological description of the plitvice lakes the plitvice lakes national park area is a typical karst environment composed almost completely of carbonate rocks (limestones and dolomites). the age of the basic rock mass is from the upper triassic up to and including the upper cretaceous (velić et al., 1974; polšak et al., 1976). sediments deposited during the quaternary period are especially important for the identifi cation of the morphostructural and hydrogeological genesis of the area. this was certainly one of the most important geological periods of the development of karst and other erosion processes in carbonate rocks of the dinarides. most of the sediments of quaternary age were formed during the exchange of glacial and interglacial ages and also in the recent period. the researchers have so far mainly focused on exploration of the tufa deposits, which is crucial for the development of lakes and waterfalls, but not on other sediments important for the identifi cation of a genetic model of the system. firstly, lake sediments occurred during the existence of isolated lakes in the dinaric karst areas. these can be expected in the bottom of the largest lakes; prošćansko and kozjak. next, layers of tufa of different ages and gravel interbeds occur within the tufa barriers. recent lake sediments do not have a high value in the identifi cation of a genetic model of the lakes, but the organic load can create problems by reducing the volumes of the lakes and the development of eutrophication in the bottom zone of the lakes. tectonic structures are important factors for the formation of surface and especially groundwater systems in the karst area of the plitvice lakes national park. according to herak (1986), the plitvice lakes area belongs to the dinarik megastructural unit. the basic feature of that megastructural unit is the existence of a thick sequence of carbonate rocks of complex tectonic structure with the appearance of tangential tectonic forms (overthrusts), interspersed with very deep karstifi cation. carbonate rocks totalling several thousand metres in thickness are fragmented into tectonic blocks by numerous faults. the plitvice lakes belong to the black sea catchment, located in the border area towards the adriatic sea catchment. almost the entire catchment of the plitvice lakes is located within the boundaries of the national park. the poorly permeable dolomites of the triassic age, which are essential for the emergence and formation of the so-called upper lakes, form a barrier to the discharge of water from the large carbonate basin on the northeastern slopes of mala kapela mountain. this surface occurrence of the oldest carbonate rocks of the area is a tectonic phenomgeologia croatica 63/2geologia croatica 198 as the quaternary period included lengthy terrestrial periods in its two million year extent, it is rather signifi cant for the interpretation of recent hydrogeological relationships. upon completion of deposition of the neogene sediments in the pannonian basin (the margins of which almost extend to the plitvice lakes), there was a period of intensive surface and groundwater erosion with the transport and selective deposition of sediments by surface streams. at the neogene/ pleistocene boundary in the karst area of the dinarides, there were many isolated lakes (now karst fi elds), and surfacewater fl ows into the lakes from the immediate catchments (herak, 1962; biondić & goatti, 1976; biondić, 1982). this is analogous to the existence of the individual (unconnected) lakes prošćansko and kozjak in the plitvice lakes area (fig. 3). the terrestrial phase resulted in development of surface and underground karstifi cation and expansion of surface catchment areas where possible according to the geological structure. the catchment of lake prošćansko (636 m) extended to mala kapela mt., while lake kozjak (535 m) only experienced mild expansion of the surface watershed because of the prevailing largely impermeable dolomites. consequences of this included increased fl ows of water to lake prošćansko, the carrying capacity of which was no longer able to maintain the water balance of such a large karst catchment, which caused erosional water penetration towards lake kozjak, 100 m below. in this manner, these two lakes, only 1700 m apart, were hydrologically connected. the increased amount of water in lake kozjak resulted in the opening of the sinks in the area downstream of the dolomite barrier, collapse of relatively thin arches of underground cavities and erosional opening of the korana river canyon. the plitvica spring and watercourse had a development cycle similar to that of lake prošćansko, with a catchment extended to the carbonate area of mala kapela with a gradual increased quantity of water fl owing to the canyon of the korana river. 3. hydrogeochemical research stable isotope analysis is an important research tool in the interpretation of the origin of groundwater and processes in the karst underground. this primarily refers to the calculation of the average altitude of the recharge area of the springs, the mean residence time in karst underground, the process of water exchange and the effects of evaporation on the lakes. in the process of research on the plitvice lakes area, 1082 samples of water collected over a two-year period were analysed. correlation of δ18o and δ2h with elevation produces an inverse linear regression (bortolami et al., 1979; fontes, 1980; abbott et al., 2000; james et al., 2000; yehdego & reichl, 2002), which enables the calculation of average altitude of recharge of aquifer. it is possible to specify the average altitude of a catchment with a graphical and mathematical regression equation (fig. 4). mean residence time is usually provided by analysis of tritium 3h, however, due to a short sampling period this is of questionable accuracy, and the stable isotope method using an exponential “fl ow model” was used (maloszewski et al., 1983; stewart & mcdonnell, 1991). the results of calculations for the karst springs supplying the plitvice lakes system show values ranging between 2.1 and 2.9 years (table 1). analyses of δ18o stable isotopes were also undertaken for water samples from the lakes (fig. 5). higher contents of δ18o were established in the surface parts of the lakes kozjak and prošćansko, while the deeper parts of the lakes had a stable content of δ18o, which is a result of high evaporation from the free surface of the lakes. in the cold part of the year, the isotopic content is equalized throughout the depth because of the substantially reduced evaporation and the effect of vertical mixing of water in the lakes. the cascade system of plitvice lakes is refl ected in the changes in δ18o and δ2h content and by the changes in evaporation effects (fig. 6). the effects of evaporation increases downstream of the springs due to temperature changes associated with the effects of altitude. hydrochemical research has consisted of a total of 3022 measurements of physico-chemical parameters and 7885 analysis of karst spring, river and lake water samples, of which only a small part, in our opinion showing the charfi gu re 3: a conceptual model of the genesis of the plitvice lakes system. a) phase of isolated lakes; b) phase of connected lake system and canyon. fi gu re 4: altitude eff ect of δ18o content in rainfall from the area of plitvice lakes. table 1: calculated residence time data from deuterium analyses. max. δ2h amplitude (‰) in spring and stream water t (year) using max. δ2h amplitude in precipitation storage volume (*106 m3) white river spring –3.65 2.1 18 black river spring –2.60 2.9 70 plitvica river spring –2.80 2.7 28 biondić et al.: the conceptual hydrogeological model of the plitvice lakes geologia croatica 199 acteristics of the water system of plitvice lakes, is presented here. it is important to show the changes in ph, specifi c electrical conductivity and ca2+, in order to understand how the whole system functions. however, the situation with the lakes is far more complex due to the internal dynamics related to seasonal climatic changes and the functions of the lakes in preserving the water quality of the system. the ph values vary between 7–8 along the water system in the carbonate terrain (freeze & cherry, 1979). rivers and lakes generally have higher values due to the reduction of carbon dioxide dissolved in the water. in the case of the plitvice lakes, spring waters are in the range of 7.2 and 7.6, and lakes between 8.0 and 8.4. specifi c electrolytic conductivity gradually decreases from the springs downstream by about 500 μs/cm, which indicates a loss of calcium carbonate by precipitation of tufa. this is particularly evident from the analyses of ca2+ (fig. 7), the values varying from 60-70 mg/l at the springs to 40-50 mg/l at the exit from the plitvice lakes system. the permanent process of tufa precipitation is an indicator of high water quality and important for the stability of tufa barriers and waterfalls. a large part of the hydrochemical research was focused on the two biggest lakes – prošćansko lake (636 m asl, area 0.68 km2, depth 37 m) and kozjak lake (535 m asl, area 0.83 fi gu re 5: changes of stable δ18o isotope with depth in both lakes. fi gu re 6: the δ2h δ18o relationship – evaporated lake basins and river outfl ow. fi gu re 7: seasonal change of ca2+ in the various water features adjacent to the plitvice lakes for the period 2005–2007. geologia croatica 63/2geologia croatica 200 km2, depth 48.5 m). three locations per lake were determined where typical hydrochemical parameters were measured at different depth temperature (t), specifi c electrical conductivity (sec), dissolved oxygen (o), ph, and eh, and samples were taken for laboratory analysis of the water for ca2+, mg2+, hco3 –, sical, sidol, pco2 , and δ18o. water temperature in the lakes is a very important parameter in determining the internal dynamics of the lakes. figure 8 indicates seasonal temperature stratifi cation of both lakes with differentiation of epilimnium zones (0–10 m), thermocline zones (10–20 m) and hypolimnium zones (deeper than 20 m). in lake kozjak during december vertical water exchange begins with isotherm process, which lasts until the end of the february. then, a new cycle of lake stratifi cation begins. the same effect is present in the hypsometric higher lake prošćansko, but due to climatic conditions, it begins a month earlier and lasts almost a month longer in the spring. hydrochemical investigations of the lakes were conducted several times, but were mostly related to the lake surface (petrik, 1958; stilinović et al., 2004) and to the sanitary condition of surface parts of the lakes. signifi cant improvements over previous studies were observed because of renovations to the waste water system in the most loaded part of the park. research in this project was focused on identifi cation of hydrogeological conceptual model of the kozjak and prošćansko lakes. from the previous researches which pointed out the problem of eutrophication of the lakes, with this research thinking about the lakes role in the natural model is completely changed. fi gu re 8: seasonal temperature stratifi cation of water in the prošćansko and kozjak lakes. fi gu re 9: specifi c electric conductivity in the prošćansko and kozjak lakes. biondić et al.: the conceptual hydrogeological model of the plitvice lakes geologia croatica 201 in order to illustrate the positive changes in thinking about the function of the large lakes, the results of depth measurements of specifi c electrical conductivity (sec), the content of dissolved oxygen, ph, redox potential (eh) and the content of carbonate species are presented. sec has generally shown a slightly higher value in lake prošćansko in relation to lake kozjak due to precipitation of calcium carbonates on tufa barriers between the two biggest lakes (fig. 9). in the depth profi les of the lakes, sec rises slightly from the surface to depths of about 20 m (thermocline zone), while there is a slight downward trend in the hypolimnium. the dissolved oxygen content (fig. 10) is a particularly important parameter for the assessment of water quality, and a good indicator of the degree of eutrophication of the lake. seasonal changes in dissolved oxygen are evident in the depths of both lakes. during the thermal stratifi cation phase, high dissolved oxygen levels are linked to the epilimnium and thermocline zones, and a continuous decrease is observed in the hypolimnium. this indicates on the activation of the process of eutrophication. during the winter, vertical mixing results in the gradual disappearance of the differentiated zones of stratifi cation, and oxygen enriched water from the shallow parts of lakes migrates to the depths thus enriching the entire mass of the lake water with oxygen, thereby interrupting the processes of eutrophication in the bottom parts. then a new cycle of stratifi cation begins and the gradual process of eutrophication of the bottom part of the lakes is resumed in spring. acidity (ph) is an important parameter in the assessment of water quality and the hydrochemical development of the fi gu re 10: distribution of dissolved oxygen content in the prošćansko and kozjak lakes. fi gu re 11: ph value with depth in the prošćansko and kozjak lakes. geologia croatica 63/2geologia croatica 202 whole environment. the consequence of dissolution of limestone and dolomite are relatively high ph values of water in the range of 8.0–8.5. during the thermal stratifi cation of the lakes, ph values are stable in the epilimnium and thermocline zones, while slightly decreased values are observed at depth in the hypolimnium. this can be associated with the increase of dissolved co2 produced by the decay of organic matter. in the isothermic phase, ph values are equalised throughout the depth of the lake (fig. 11). the redox potential (eh) characterises the oxidationreduction state of natural waters. values are infl uenced by the dissolved oxygen content. redox potential in the lakes is stable in the epilimnium, thermocline and in most parts of hypolimnium zones, and this is an indicator of the expressed oxidation conditions. in the bottom parts of the lakes near the contact with the lake sediments (mud), eh values fall drastically into negative values, which is an indication of reducing conditions (fig. 12). the content of the carbonate species (ca, mg, hco3) in the lakes varies from time to time. during vertical mixing of the water masses, concentrations of ca and mg are generally uniform throughout the depth of the lake. during periods of temperature stratifi cation, a decrease of mg and increase of ca concentrations are observed with depth. lake water is generally oversaturated with calcite and dolomite throughout the monitored period. hydrogeochemical research clearly shows the dynamic model of the lake water mass with the pronounced effect of thermal stratifi cation and vertical mixing of water masses during the isothermal period. the importance of vertical mixing of water masses is evident in the enrichment of the bottom part of the lake with oxygen. without such water mixing, the lakes would gradually become fully reducing. 4. water retention in kozjak lake lake kozjak has a vital role for tourists visiting and being accommodated in the plitvice lakes national park. up to 100 l/s of water are exploited from the lake for the supply of the national park and numerous villages on its north side. it is important to emphasize that lake kozjak is located on the north-eastern edge of the so-called plitvice barrier (dolomite), in the zone of strong longitudinal regional faulting. the lake includes some very permeable carbonate rocks with the potential for water loss from the lake system. while this is a large area for tourism, it is also one with previously poorly understood hydrogeological relationships between the lake and very permeable underground karst areas to the north – east that are potentially very vulnerable. therefore, part of the research project was directed towards identifi cation of these relationships between lake kozjak and groundwater on the northeastern side of the lake. two exploration-piezometric boreholes were drilled in this area, located on the base of the detailed hydrogeological map at 1:5.000 scale, and geophysical surveys (shallow seismic refl ection, tomography, electromagnetic sounding and electromagnetic profi ling) (fig. 13). piezometric boreholes were drilled to depths greater than the deepest part of lake kozjak. the fi rst (pj–1), is upstream, near the hotel, and the other, (pj–3) is located at the downstream end of the lake towards the lower lakes. in the upstream borehole, no active groundwater was found to a depth greater than 40 m below the lake, regardless of the hydrologic conditions, suggesting the “hanging” nature of lake kozjak in relation to the environment. it is possible to expect the existence of a negative gradient of the lakes in relation to groundwater, but such a large gradient means there is a latent risk of loss of water from the largest lake system. the surprise was the appearance of caverns fi lled with tufa at depths below lake kozjak, suggesting the existence of fossil sinks during the development of the youngest quaternary period. sinks are fi lled with tufa, which has enabled a signifi cant increase in the water retention capability of the north-eastern fl ank of lake kozjak and practically makes active water losses from the lake impossible. however, fossil sinks fi lled with relatively porous tufa certainly increase the high risk status of the northeast side of lake kozjak. a fi gu re 12: distribution of redox potential with depth in the kozjak and prošćansko lakes. biondić et al.: the conceptual hydrogeological model of the plitvice lakes geologia croatica 203 similar situation occurs with the downstream borehole, where groundwater has been registered, but with a pronounced negative gradient with respect to kozjak lake and the lower lakes. detailed hydrogeological research has highlighted the previously unknown high risk to the survival of lake kozjak. in addition, it has highlighted the importance of tufa and active processes of tufa precipitation in maintaining the northeast margin of the lake, and the openness of the karst underground on the northeast side of the lake with the wider environment. the direction of groundwater runoff from the area of the plitvice lakes was determined by groundwater tracing tests. in a natural cave, 30 kg of uranine dye tracer was injected with about 60 m3 of water. after 19 days, the tracer registered in the samples and visually occurred in the klokot spring near bihać in neighbouring bosnia and herzegovina, 17.6 kilometres from the place of injection (fig. 14). 5. water loses research along the plitvica stream the plitvica stream is a very signifi cant part of the water resources of the plitvice lakes national park, as it supplies the big waterfall with water. the big waterfall is a visually very attractive part of the park, which, together with the waters of the lakes forms the spring zone of the korana river. in the last ten years, the amount of water fl owing over the big waterfall in periods of drought has been severely reduced and this is a big problem for the park, because one of the most beautiful waterfalls of the park practically disappears (fig. 15). the plitvica spring is the third largest karst spring in the plitvice lakes system. water from karst underground springs on contact with very permeable carbonate rocks of the mala kapela mountain area and the dolomite barriers of the plitvice lakes. the maximum amounts of discharge are about 6 m3/s and in such conditions the water losses along the river bed upstream of the big waterfall are practically invisible. however, during the summer dry periods, the fl ow just before the big waterfall is reduced to the minimum of 30 l/s, which is disastrous for the big waterfall, meaning that it is practically dry. flow measurements were made at three places along the plitvica stream, mainly during the dry periods, when the effects of sinking are visible (fig. 16). thus, for example, in an extremely dry period in the month of october 2006 265 l/s of water (100%) fl owed from the spring zone. on the measuring profi le downstream in the central part of the watercourse, there was 140 l/s (53%), and before the big waterfall only 74 l/s (38%) was measured. fi gu re 13: locations of piezometric boreholes pj-1 and pj-3, hydrogeological cross-section and core of cavern with tufa from borehole pj-1. fi gu re 14: results of the tracing test of the doline in rastovača in the plitvice lakes national park. fi gu re 15: the big waterfall during dry and rainy periods. geologia croatica 63/2geologia croatica 204 there is several cause of this water loss along the plitvica stream. firstly, the stream crosses dolomite barriers in the area composed of very permeable limestone. however, the situation is further complicated by the distribution of the natural tufa sediments, which generally have a positive hydrogeological function of helping to retain water along the bed of the watercourses. tufa deposition in the bed of watercourse is so intense that the bed is constantly raised with new layers and water outfl ows from the raised bed to the adjacent meadows without tufa, but with numerous dolines, where water sinks in the calcareous subsoil. the question can be asked as to why water losses were lower in the past. reasons include the activities of the local inhabitants, who are now more concerned with tourism and do not care too much for cleaning and cutting troughs in the tufa and releasing the meadows from water. solutions are to strive to maintain the system at the level of previous use, even without the need to use the meadows. water that is lost in the underground karst system most likely disappears from the plitvice lakes system into the adjacent una river catchment area or springs downstream in the korana river. 6. discussion the plitvice lakes national park is located in the central part of the dinarides, an area characteristic of the development of specifi c surface and underground morphological forms resulting from dissolution by water. large karst springs, lakes and waterfalls are the fundamental phenomena of the national park attracting almost a million visitors a year. the catchment of karst springs, which supplies the plitvice lakes with water, is composed of carbonate rock of the mesozoic age. it extends to the northern slopes of the mountain areas of mala kapela and is about 150 km2 in size. groundwater fl ow from the catchment is of relatively large apparent speeds towards the springs (polšak, 1974), indicating relatively short periods of water retention in the karst underground, and at the same time suggests a high degree of natural vulnerability for most of the catchment. the consequences are the large variation in discharge in the karst springs, which range from 0.6 m3/s in dry periods and 11.6 m3/s in rainy periods. from the total amount of discharge from the spring zone, the black river spring produces about 75% of the water, with the remaining 25% from the white river spring. poorly permeable dolomites of the upper triassic age form barriers to the discharge. streams of both springs are combined in a common watercourse and fl ow into the uppermost lake prošćansko. the plitvica spring varies between 0.3 and 5.92 m3/s. water from the lake prošćansko fl ows throughout the numerous lakes and waterfalls created by deposition of tufa to the largest lake kozjak. hydrological measurements show that there are no water losses up to and including lake kozjak in the plitvice lakes system due to dolomite barriers. because of the regional fault along the north-eastern side of lake kozjak, a part of the lake is located in the permeable part of the geological structure. thick deposits of tufa and probably lake sediments from the early stages of development of the lake have a positive hydrological function. downstream from the last lake, the plitvice lakes water system is connected by the big waterfall of the plitvica stream and the beginning of the korana river. along the plitvica stream, signifi cant losses of water occur in the karst underground with an unknown direction of underground fl ow, signifi cantly reducing the fl ow of water over the big waterfall during summer dry periods. possible losses of the water prior to the spring zone of the korana river are minimal due to tufa sediments, which fi ll the old cracks and sinkholes, but the downstream losses increases and after only 1 km the korana river is dry during the summer periods. the korana river remains dry until the fl ow reaches 1.1 m3/s and with the increase of fl ow the river fl ows over its entire length. water sinking from the korana river drains into the catchment of the river una, towards the main water-supply spring of bihać (klokot) located in the neighbouring state (biondić et al., 2008). this is the general principle of how the plitvice lakes function, but the system is far more complex because of the existence of large lakes, which function independently. the prošćansko and kozjak lakes have a very important position for the functioning of the plitvice lakes system. detailed hydrogeochemical research has discovered that both lakes have very similar internal dynamics, which is very important in preventing eutrophication of the whole plitvice lakes system. annual stratifi cation of the water mass was determined in both lakes together with vertical mixing during the isotherm phase of the lakes. it is important to note that in both lakes during stratifi cation, reducing conditions occur in the bottom waters with greatly reduced amounts of dissolved oxygen due to decay of organic matter. with vertical mixing, in the lakes, water enriched with oxygen migrates from the surface zone towards the bottom and thus oxygen enriches the deepest parts of the lakes and prevents the further spread of eutrophication processes. all the analyses of stable isotopes and hydrochemical parameters in this research project confi rm such a state. the height of zones of reducing conditions in the lakes could be an indicator of the sustainability of water quality during the stratifi cation of the lake water mass. the trend of increasing height of that reduction zone can certainly be an indicator of the progress of the fi gu re 16: meadows adjacent to the plitvica watercourse where water sinks. biondić et al.: the conceptual hydrogeological model of the plitvice lakes geologia croatica 205 process of lake eutrophication, and a warning for the introduction of additional measures to protect the whole system. the detail research opened the serious problem in the central visiting area of the national park on the north-eastern part of lake kozjak. in that area the problem could be opening of the fossil sinks fi lled with tufa sediments. it is a high risk part of the national park, where future development should given special attention. most tourist attractions are located in the area at risk, where each uncontrolled construction activity may cause changes in natural systems. a signifi cant problem is the water loss along the river bed of the plitvice stream, where the amount of water in one of the main attractions; the big waterfall, is severely reduced in the summer. reduction of losses should be carried out very carefully within the limits of previous activities of the local population. 7. conclusion water resources are the fundamental natural phenomenon of the plitvice lakes national park, and their quality and quantity directly affect the exceptional biodiversity of the entire region. due to the natural dynamics of the lakes, despite the burdens of natural systems with a large number of visitors, hotels and transportation, the exceptional quality of lake water has been preserved. the research identifi ed completely new data on the genesis of the water system of plitvice lakes, hydrogeological characteristics of karst springs and their catchment areas, dynamics of the lake water, and also a whole range of data relating to the preservation and protection of groundwater and surface water in the catchment area. research has also indicated the most sensitive areas of the water system of plitvice lakes to which special attention should be paid. acknowledgment the project “sustainable utilization of water in the pilot area plitvice lakes” was undertaken within the kompetenznetwerk wasserressourcen gmbh, co-fi nanced by the plitvice lakes national park and the austrian government. the authors wish to thank all associates from joanneum research (graz, austria) and the research centre “ivo pevalek” from plitvice lakes who made signifi cant contributions and enabled the successful execution and completion of the project. references abbott, a., lini, a. & bierman, p.r. (2000): δ18o, δd and 3h measurements constrain groundwater recharge patterns in an upland fractured bedrock aquifer, vermont, usa.– j. hydrol., 228, 101− 112. babinka, s. (2007): multi-tracer study of karst waters and lake sediments in croatia and bosnia – herzegovina: plitvice lakes, national park and bihać area.– ph.d. thesis, rheinischen friedrichwilhelms-universität bonn, 167 p. biondić, b. (1982): hidrogeologija like i južnog dijela hrvatskog primorja [hydrogeology of the lika region and southern part of the hrvatsko primorje region – in croatian].– unpubl. phd thesis, university of zagreb, faculty of science, zagreb, 214 p. biondić, b. & goatti, v. (1976): regionalna hidrogeološka istraživanja like i hrvatskog primorja [regional hydrogeological researches of lika and hrvatsko primorje – in croatian].– technical report, croatian geological survey, zagreb, 123 p. biondić, b., zojer, h., biondić, r., beyene, y., kapelj, s., meaški, h. & zwicker, g. (2008): mountainous lakes – sustainable utilization of water in the pilot area plitvice lakes.– in: probst, g., probst, e., probst, m., schafranek, s. & trubswasser, b. (eds.): wasserressourcen und deren bewirtschaftung – die bedeutung von netzwerken. internationale fachtagung. kompetenznetzwerk wasserressourcen gmbh, graz, 109– 117. bortolami, g.c., ricci, b., susella, g.f. & zuppi, g.m., (1979): isotope hydrology of the val corsagilia, maritime alps, piedmont, italy.– isotope hydrology, iaea, vienna, 327–350. fontes, j.ch. (1980): environmental isotopes in groundwater hydrology.– in: fritz, p. & fontes, j.ch. (eds): handbook of environmental isotope geochemistry – the terrestrial environment, 1, 75–140. freeze, r.a. & cherry, j.a. (1979): groundwater.– prentice-hall, inc., new jersey, 604 p. herak, m. (1962): tektonska osnova hidrogeoloških odnosa u izvorišnom području kupe i korane, s plitvičkim jezerima [tectonical basis for hydrogeological relations in spring zone of rivers kupa and korana, with plitvice lakes – in croatian].– v. savjetovanje geologa fnr jugoslavije, beograd, 17– 25. herak, m. (1986): a new concept of geotectonics of the dinarides.– acta geol., 16/1, prirod. istr. jazu, 53, 1–42. james, e.r., manga, m., rose, t.p. & hudson, g.b. (2000): the use of temperature and the isotopes of o, h, c, and noble gases to determine the pattern and spatial extent of groundwater fl ow.– j. hydrol., 237, 100–112. maloszewski, p., rauert, w., stichler, w. & herrmann, a. (1983): application of fl ow models in an alpine catchment area using tritium and deuterium data.– j. hydrol., 66, 319–330. petrik, m. (1958): prinosi hidrologiji plitvica [contribution to the hydrology of plitvice – in croatian].– in: šafar, j. (ed): poljoprivredni nakladni zavod, zagreb, croatia, 49–173. polšak, a. (1974): geološki aspekti zaštite plitvičkih jezera [geological aspects of protection of the plitvice lakes – in croatian].– čovjek i priroda, np plitvička jezera, 23–32. polšak, a., juriša, m., šparica, m. & šimunić, a. (1976): osnovna geološka karta sfrj 1: 100,000, list bihać, l 33-116 [basic geological map of yugoslavia 1:100000, bihać sheet – in cro atian].– geološki zavod, zagreb, savezni geološki zavod, beograd. ridjanović, j. (1976): hidrogeografske značajke nacionalnog parka plitvička jezera [hydrogeographical features of the national park plitvice lakes – in croatian].– in: geografski vjesnik, 38, 246–252. stewart, m. & mcdonnell, j.j. (1991): modeling base fl ow soil water residence times from deuterium concentrations.– water resour. res., 27/10, 2681–2693. stilinović, b., habdija, i. & dujmović, a. (2004): kakvoća vode ekosustava plitvičkih jezera od godine 1977. do 2003. na teme lju bakterioloških analiza [ecosystem plitvice lakes water quality in period 1977–2003 on the basis of bacteriological analyses – in croatian].– in: pavlus, n., dujmović, a., belančić, a., čulinović, k., zwicker, g. & belančić, d. (eds.): plitvički bilten, 6, 83–92. velić, i., bahun, s., sokač, b. & galović, i. (1974): osnovna geološka karta sfrj 1: 100 000, list otočac, l 33-115 [basic geological map of yugoslavia 1:100000, otočac sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. yehdegho, b. & reichl, p. (2002): recharge areas and hydrochemistry of carbonate springs issuing from the semmering massif, austria, based on long-term oxygen-18 and hydrochemical data evidences.– hydrogeol. journal., 10, 628–642. geologia croatica 63/2geologia croatica 206 zwicker, g., rubinić, j. & kompar, d. (2006): hydrology of plitvice lakes and the upper korana – correlation and trends.– in: bruk, s. & petkovic, t. (eds.): conference abstracts of 23rd conference of the danube countries on the hydrological forecasting and hydrological bases of water management, august 28–31, 2006, serbia, belgrade, 67–68. zwicker, g. & rubinić, j. (2005): the water level fluctuations as an indicator of tufa barriers growth dynamics in the plitvice lak es.– rmz, materials and geoenvironment, 52/1, ljubljana, 161–163. manuscript received february 01, 2010 revised manuscript accepted may 04, 2010 available online june 28, 2010 esenli et al.indd 1. introduction the pyroclastic rocks have extensive zeolite reserves in nature. this is due to their high volcanic glass content and porosity. composition of volcanic material as well as the ease of circulation of solutions influences dissolution of volcanic glass and the formation of zeolites. the crystallization sequence of minerals and reaction products during rock–solution interaction depends on the chemical composition of the starting material, contact of solution with volcanic glass and minerals of the pyroclastic rocks, rock–solution interaction time, temperature, pressure, ph, geological environment and hydrological systems (boles, 1988; barthwirshing & holler, 1989). analcime, mordenite and clinoptilolite are usually regarded as diagenetic zeolitization of tuffaceous rocks in the keşan region, thrace, turkey fahri esenli̇, bektaş uz, fikret suner, vildan esenli̇, ö. işık ece and işık kumbasar products of glassy volcanic material. they can form in closed or open hydrological systems, in deep-sea sediments, in hydrothermal alteration zones and, as a result of low-grade burial metamorphism (iijima & utada, 1966; hay, 1981; gottardi & galli, 1985). the distribution of analcime-bearing and analcime-absent zones differs horizontally or vertically depending upon chemical zoning in these environments. inner or deeper zones are characterized by the existence of analcimes (hay, 1981). analcime is low silica zeolite, so that generally the si/al ratio is 2, while this ratio ranges from 2 to 3 for sedimentary analcimes (gottardi & galli, 1985). na is the only extra-framework cation in analcimes. mordenite and heulandite–clinoptilolite are high silica zeolites. the si/al ratio of mordenites ranges from 4.2 to 5.9, and their cation contents per unit cell are 1.6–2.5 for ca, 2.0–5.0 for na and 0.1–0.8 for k (passaglia, 1975). however, in some examples k is reported as the dominant cation (coombs et al., 1997, and references therein). heulandites have been distinguished from isostructural clinoptilolites on the basis of their si/al ratios – heulandites having si/al<4 and clinoptilolites having si/al>4. the clinoptilolite structure is more stable than that of heulandite and calcic clinoptilolite (mason & sand, 1960; alietti, 1972; boles, 1972; alietti et al., 1977). the cation contents in heulandites and clinoptilolites are highly variable and therefore ca-, na, kand sr-heulandites and ca-, naand k-clinoptilolites are commonly known (coombs et al., 1997). the significance of zeolitization in tuffaceous rocks in sw keşan (thrace, northwest turkey – fig. 1), the occurrence, stratigraphic position and mineralogical characteristics of zeolite-bearing levels are discussed in this study. some zeolite occurrences in the upper eocene–oligocene pyroclastics from thrace (in the vicinity of gelibolu and uzunköprü areas and the southeast of keşan) have been previously reported (esenli̇ et al., 1997a; i̇çöz & türkmenoğlu, 1997). these occurrences contain the heulandite–clinoptilolite type of zeolites in the gelibolu and uzunköprü areas and analcime and clinoptilolite in se keşan. in this study, the zeolites, including analcime, mordenite and heulandite–clinoptilolite, were described stratigraphically as alternate layers in the sw keşan. the objective of this paper is to characterize the zeolitization and to explain the formation of analcimeand mordenite (+heulandite– clinoptilolite)-rich levels. geologia croatica 58/2 151–161 5 figs. 4 tabs. zagreb 2005 key words: analcime, clinoptilolite, heulandite, mordenite, tuffaceous rocks, zeolitization, thrace, turkey. istanbul technical university, geology department, maslak, 34469 istanbul, turkey; e-mail: esenlif@itu.edu.tr abstract a 33 metre thick pyroclastic-rich zone of the mezardere formation of oligocene age is exposed in the keşan region of thrace, turkey. in this zone, vitreous tuffs of dacitic composition have altered primarily to zeolites, including mordenite, heulandite–clinoptilolite and analcime. silicification and alteration to clay minerals are common. zeolite minerals have developed from volcanic glass, whereas some mordenites have formed from dissolution of heulandite-group zeolites. although authigenic mineral paragenesis does not vary laterally, there is a marked vertical variation, particularly in zeolites. mordenite (+heulandite–clinoptilolite) and analcime do not coexist and have formed in different stratigraphic levels. this suggests that their chemical environment is controlled by different hydrologic systems. whole rock composition shows the relationship between chemistry and secondary mineralogy. for example, whole rock trace element geochemistry indicates the natural selectivities of zeolites. there is also stratigraphic control on the chemistry and texture of mordenites. specifically, (na+k)/(ca+mg) ratios of mordenites decrease from the lower to the upper levels. mordenites of the lower level show a fibrous habit while the upper level mordenites are needle-like in shape. the average si/al ratio in mordenites is 3.90, in heulanditegroup minerals 3.95, and in analcimes 2.34. 152 geologia croatica 58/2 2. geological setting 2.1. thrace basin the thrace basin is surrounded by the stradja massif in the north, the rhodope massif in the northwest and the menderes metamorphic massif in the south. it is on the intra-pontide suture zone, which was developed by the northward subduction of the northern branch of the neo tethys ocean during the late cretaceous–early tertiary period (şengör & yilmaz, 1981; yilmaz et al., 1997) and continental collision of the stradja and sakarya zones (okay & tüysüz, 1999). the thrace basin started to open at the end of the middle eocene, and sedimentation started as a transgressive process; however, environments of deposition significantly changed at the end of the early miocene and were later completed as regressive sedimentation (turgut et al., 1983, 1991). thus, in the stratigraphic succession, fine-grained sediments of flysch facies proceed to shale, marl, limestone, coal and sandstone indicating lacustrine, fluvial and shallow marine depositional environments. during the late oligocene–early miocene, the basin was wholly elevated and previously deposited sedimentary rocks were subjected to erosion. the middle miocene tectonic activity caused folding and faulting along the edges of the basin. during the late miocene, thick successions of conglomerate, sandstone, claystone and coal series were overlain on the pre-miocene rocks across regional disconformities. the thickness of sedimentary rocks reaches up to 8 km in the centre of the thrace basin (turgut et al., 1983, 1991). volcanic eruptions were synchronous with the maximum of the transgressive episode of the thrace basin. voluminous volcanic products with dacitic and andesitic composition form tuffaceous interbeds within sedimentary rocks or the tuffaceous matrix of clastic rocks. petrographic and geochemical classification of the thrace volcanic rocks presented by yilmaz & polat (1998) and genç (1998) are as follows: calc alkaline–intermediate volcanic products were extruded during the late eocene–early miocene period. this fig. 1 the location, geological map and stratigraphic section of the study area (sw keşan). 153esenli et al.: zeolitization of tuffaceous rocks in the keşan region, thrace, turkey first phase is assumed to be a product of tibetian-type volcanism developed under the n–s compressional regime of northwestern anatolia. the second volcanic phase started during the late miocene and is represented by alkaline basaltic lavas extruded sporadically in different parts of the thrace region. 2.2. keşan region the keşan formation (upper eocene) is the lowest part of the stratigraphic succession in the study area (sw keşan, fig. 1). it consists of turbiditic sandstones and minor shales and marls that are conformably overlain by the lower–middle oligocene mezardere formation, described by turgut et al. (1983). the latter is unconformably overlain by the miocene–pliocene ergene formation. turgut et al. (1983) infers that the keşan formation was formed in a marine environment and the mezardere formation indicates lacustrine and shallow depositional environments. ternek (1949) and koop et al. (1969) described the volcanic activity (andesitic and dacitic lavas and tuffs) in the keşan region throughout the oligocene epoch. koop et al. (1969) reported an approximately 20 m thick pyroclastic bed named the “keşan tuffs” between the keşan and mezardere formations. towards the upper oligocene, andesitic, dacitic and trachytic lavas became dominant. ercan et al. (1998) reported that andesitic lava from the keşan area yields a k/ar age of 26.2±0.5 my (late oligocene, chattian). in the study area (sw keşan, fig. 1), tuffaceous rocks repeatedly occur both in the upper part of the keşan formation and throughout the mezardere formation. they are characterized by dacitic–andesitic tuffs interbedded with marls and sandstones. zeolite-bearing tuffaceous rocks are constrained to the lower part of the mezardere formation, and are exposed between the villages of karahisar and kızkapanı in an area of about 1.5 km2 (fig. 1). the thickness of this zone is 33 m in a quarry in the kızkapanı (see fig. 5) and 20 m in the karahisar areas. trachytic lavas that appear as hills in the study area are probably younger than the pyroclastics. 3. methods nineteen samples have been studied stratigraphically in detail: fourteen zeolite-bearing pyroclastic, one nonzeolitic pyroclastic and four clastic rock samples. the samples were studied petrographically and mineralogically by polarizing microscope and x-ray diffractometer. a philips diffractometer with cu (kα) radiation was used for x-ray powder diffraction (xrd) analyses and powder samples were scanned at 1°2θ per minute. major element compositions of rocks have been determined by the x-ray fluorescence (xrf) method. powdered rock samples have been fused using libo2 and the resulting glass disks have been analyzed in the research laboratory of turkish glass inc. rigaku; rix– 2000 model equipment was used for xrf analyses. trace elements were analyzed by using spectro ciros vision icp–es for ba and sc (0.200 g pulp sample by libo2 fusion) and mo, cu, pb, zn, ni, as (0.50 g sample leached with 3 ml of 2–2–2 hcl–hno3–h2o at 95°c for one hour, diluted to 10 ml) and by perkin elmer elan 6100 icp–ms for the other elements in the acme analytical laboratories, vancouver, canada. morphological characteristics and chemical compositions of zeolites (mordenite, analcime and heulandite–clinoptilolite) were investigated on a jsm–840 type scanning electron microscope (sem) and a tracor northern 5400 energy dispersive x-ray spectrometer (edx). structural formulas of zeolite minerals were calculated on the basis of 72 oxygen for clinoptilolites and 96 oxygen for mordenites and analcimes using unnormalized oxide values. the quality of the analyses was calculated by evaluating the balance error given by gottardi & galli (1985). the balance error of the mordenite and heulandite–clinoptilolite samples ranges 9–29% (however, ba, sr and li were not analyzed). 4. results and discussion 4.1. whole rock the zeolite minerals are closely related to vitric tuffs of dacitic–andesitic composition. there is no clear difference in physical appearance between mordenite (+heulandite–clinoptilolite)-rich and non-zeolitic exposures in the field. they are massive and beige–pale green in colour. the analcime-rich outcrops, however, have a dark gray colour and are brittle which distinguishes them from the mordenite (+heulandite–clinoptilolite)-rich and non-zeolitic outcrops of tuffaceous rocks. phenocrysts of tuffs consist of plagioclase (oligoclase–andesine), biotite, amphibole (hornblende), quartz and opâque minerals. the phenocryst content ranges from 2 to 60 vol. %. volcanic glassy material (glass shards and pumice fragments) has authigenetically transformed to zeolites (analcime, mordenite and heulandite–clinoptilolite), smectite (dioctahedral montmorillonite), silica minerals (opal-ct and quartz) and calcite. mordenite, heulandite–clinoptilolite, smectite and opal-ct could not be identified optically. analcimes are mostly anhedral. calcites occur as pore-filling crystals as well as the alteration products of plagioclases. quartz is present as both phenocrysts and as a secondary mineral, and the majority of it is of authigenic origin. the mineralogical compositions of the samples determined by xrd analysis are listed in table 1. samples from 1 to 19 are arranged stratigraphically from the lower to the upper zone (see fig. 5). samples numbered as 3, 7, 12 and 15 are of marl and sandy calcareous composition and the rest is of tuffaceous material. sample 8 is the only pyroclastic rock which does not contain any 154 geologia croatica 58/2 zeolite mineral. mordenite is identified in twelve samples and analcime is found only in samples 9 and 14. these minerals are generally the major components of rock samples according to the xrd patterns (fig. 2). analcimeand mordenite-bearing levels alternate in the stratigraphic sequence. lesser amounts of heulandite–clinoptilolite are associated with mordenite in five samples (5, 6, 10, 11 and 19). smectite is identified in ten samples, and it is the main mineral in sample 16. opal-ct in three samples is from the middle level of the zeolite-bearing zone. the major element compositions of nine rock samples and trace element analyses of eleven samples are given in tables 2 and 3, respectively. plotted on the zr/tio2–nb/y diagram of winchester & floyd (1977), most of the samples fall in the dacite–rhyodacite field (fig. 3). only sample 5 is trachyandesite and sample 9 is andesite. there is a relationship between the whole rock chemistry and secondary mineralogy of the samples. for example, the sio2 content of analcimerich samples is low, but high in mordenite-rich samples. cao, except sample 8, is between 3.23 and 4.17 wt. %. the high cao of sample 8 (9.17%) is probably due to the presence of calcite in this sample. fe2o3 contents of samples 8, 9, 11, 14 and 16 are higher than those of other samples. according to the xrd results, sample 8 contains a trace amount of illite. on the other hand, thin-section observations revealed that illite–celadonite minerals seen in the matrix, in voids and in pheno sample mineralogy 1 mordenite+quartz 2 mordenite+quartz+feldspar 3 calcite+quartz+illite 4 mordenite+smectite+quartz 5 mordenite+heulandite–clinoptilolite+smectite+quartz 6 mordenite+heulandite–clinoptilolite+smectite 7 calcite+quartz+illite+kaolinite+feldspar 8 quartz+feldspar+calcite+illite 9 analcime+quartz+feldspar 10 quartz+mordenite+heulandite–clinoptilolite+opal-ct+feldspar+smectite 11 mordenite+quartz+heulandite–clinoptilolite+opal-ct+calcite 12 quartz+calcite+feldspar 13 mordenite+smectite+opal-ct+feldspar+calcite+quartz 14 analcime+quartz+smectite+feldspar 15 quartz+calcite+kaolinite+illite+feldspar 16 smectite+mordenite+feldspar 17 mordenite+quartz+feldspar+smectite 18 mordenite+quartz+smectite 19 mordenite+quartz+feldspar+heulandite–clinoptilolite+smectite table 1 the mineralogical composition of pyroclastic and clastic rocks of sw keşan determined by xrd. sample 1 5 8 9 11 14 16 18 19 sio2 65.91 66.17 56.60 61.07 65.49 61.47 63.22 66.43 67.36 al2o3 14.01 13.49 14.00 16.01 13.50 15.45 14.18 13.29 13.93 fe2o3 1.61 1.31 5.57 2.74 3.47 2.84 3.01 1.82 1.76 mno 0.16 0.21 0.28 0.11 0.05 0.16 0.17 0.17 0.10 tio2 0.28 0.34 0.85 0.64 0.35 0.42 0.60 0.38 0.33 mgo 1.31 1.71 2.35 2.37 1.63 2.20 2.85 1.90 1.98 cao 3.51 3.54 9.17 3.53 3.30 3.28 3.12 4.17 3.23 k2o 1.66 2.65 2.98 1.95 2.92 2.10 2.83 2.87 2.74 na2o 2.88 1.50 2.59 3.90 0.71 4.15 1.31 1.33 1.18 p2o5 0.11 0.07 0.35 0.14 0.08 0.13 0.13 0.12 0.09 loi 8.56 8.01 5.26 7.54 8.50 7.80 8.58 7.52 7.30 table 2 whole rock chemistry (wt. %) of the samples. 155esenli et al.: zeolitization of tuffaceous rocks in the keşan region, thrace, turkey crysts of samples 8, 9, 10, 11 and 14, are products of alteration. these clay-group minerals were not detected in xrd patterns except in sample 8. therefore the presence of illite–celadonite minerals might explain the high fe2o3 in samples 8, 9, 11, 14 and 16. in addition, mordenites in these samples also contribute some amounts of iron. indeed, single crystal analyses (table 4) show that mordenites have a high content of fe. k2o and na2o range between 1.66–2.98% and 0.71–4.15%, respectively. na2o of the non-zeolitic sample 8 is higher than that of mordenite-rich samples and reaches its highest values in analcime-rich samples. the results of the trace element chemistry can be summarized as follows: (a) co, v, zn, ni, y, sm, eu, gd, tb, dy, tb, ho, er are higher in sample 8 containing no authigenic zeolite mineral; (b) samples 9 and 14 are richer in analcime and cs, mo, rb, u, zr, cu, pb are higher in these samples, and (c) ba, sr, th, la, ce and as of mordenite-bearing samples 1, 5, 10, 11, 13, 16, 18 and 19 (table 3), are higher than the average values of all other samples studied. it is also determined that samples containing mordenite+heulandite–clinoptilolite have higher average values for ba and sr than those of the mordenite-rich group. on the other hand, considering the stratigraphic positions of mordenite-bearing samples, the upper levels are richer in ba, rb, sr, ti, u, w and as, while the lower levels are richer in mo, cu, pb, zn, and y–lu series. 4.2. zeolites mordenites of the tuffaceous rocks (sw keşan) show fibrous and needle-like habits (figs. 4a and b). the mordenite needles are about 3–20 μm in length and 0.3–1 μm in width, whereas the widths of fibres of thread-like mordenites are generally less than 0.2 μm. mordenites have formed as individual crystal and also as radial from a nucleus (fig. 4c). they have mostly developed from volcanic glassy material. the fibres are growing from the top of the vitrified volcanic glass, which displays a parallel fractured alteration pattern as shown in fig. 4d. however, some mordenites of sample 19 have been observed as tiny crystals on heulanditegroup crystals (fig. 4e). in this case, heulandites–clinoptilolites transformed to mordenite crystals which were in the form of dissolved grains and do not exhibit their fig. 2 the xrd patterns of analcime and mordenite-bearing samples (a: sample 14, and b: sample 17). 156 geologia croatica 58/2 monoclinic idiomorphic habits. these heulandite-group minerals were probably transformed to mordenites after dissolution. pe-piper (2000) reported transformations between heulandite-group and mordenite-group minerals, which are depending on the changes in temperature. kitsopulos (1997) also reported the mordenites from the polyegos island, greece, which are draped over and formed from the crystals of heulandites. the average structural formulae of the keşan mordenites was calculated on the basis of 96 oxygen to [ca1.7 mg1.3 na2.0 k1.6] [(fe, al)9.6 si37.4 o96 ] · 28h2o. they show the si/al ratio ranging from 3.60 to 4.36 with an average value of 3.9 and the average value of the (na+k)/(ca+mg) ratio is 1.2 ranging from 0.90 to 1.57 (table 4). the obtained si/al ratio is lower than those corresponding to hydrothermal mordenites. passaglia (1975) showed that there are no large variations in the chemical composition of mordenites with probably sedimentary and hydrothermal origin, however, according to godovikov (1985) hydrothermal mordenites have higher silica and water contents than sedimentary mordenites. chemical compositions of the keşan mordenites exhibit variations across the stratigraphic sequence (see table 4 and fig. 5). the ratio of alkali/earth alkali cations decreases toward the upper levels. this difference can be clearly seen in the com sample 1 5 8 9 10 11 13 14 16 17 18 as 4 17 3 4 4 5 4 3 4 5 4 ba 658 1585 333 623 1020 873 698 210 636 571 869 ce 57.9 55.4 50.7 56.8 52.1 64.0 62.0 55.1 59.8 63.5 58.3 co 6.3 1.8 12.6 7.7 5.3 3.6 3.9 4.0 6.9 6.8 7.7 cs 4.3 2.9 2.9 11.3 2.5 2.6 3.1 12.2 4.4 3.0 5.3 cu 9 4 6 11 10 6 6 7 7 6 8 dy 2.33 1.46 3.72 2.94 2.73 2.47 2.56 2.50 2.47 2.25 2.29 er 1.49 1.11 2.23 1.85 1.45 1.70 1.69 1.67 1.65 1.22 1.55 eu 0.62 0.44 1.25 0.89 0.67 0.68 0.76 0.71 0.7 0.67 0.59 ga 14.7 13.4 15.0 15.3 11.9 14.5 15.4 13.9 15.8 13.7 14.7 gd 2.58 1.93 4.37 3.57 2.42 2.61 2.64 3.15 2.82 2.33 2.74 hf 4.3 4.2 4.6 5.1 3.6 4.7 5.0 5.0 4.7 4.1 4.3 ho 0.43 1.31 0.78 0.62 0.48 0.51 0.52 0.50 0.51 0.41 0.48 la 32.1 35.6 24.6 31.6 30.0 36.0 35.3 30.0 33.2 34.1 30.1 lu 0.22 0.21 0.34 0.35 0.27 0.32 0.34 0.30 0.29 0.28 0.26 nb 7.6 8.2 6.2 8.7 7.0 9.1 8.6 10.5 9.1 7.6 7.7 nd 18.9 17.1 24.2 21.1 18.4 22.4 21.4 21.2 22.7 20.6 20.1 ni 7 4 18 13 6 2 3 17 13 7 14 mo 0.3 0.4 0.3 1.1 0.6 0.2 0.3 0.2 0.2 0.4 0.2 pb 33 39 1 32 28 35 35 23 39 36 33 pr 5.83 5.60 6.16 6.20 5.49 6.61 6.4 5.76 6.32 6.09 5.60 rb 89.8 77.5 69.2 91.0 85.5 65.4 72.8 100.7 75.0 78.0 77.3 sm 3.4 2.6 5.2 4.0 3.0 3.8 3.6 3.3 3.9 3.2 3.5 sr 1112 1882 433 731 1679 1585 1060 201 819 920 1232 ta 0.7 0.7 0.3 0.6 0.6 0.7 0.6 0.7 0.7 0.7 0.7 tb 0.42 0.30 0.73 0.57 0.42 0.44 0.5 0.43 0.48 0.38 0.43 th 18.7 1.8 6.9 17.7 16.3 23.6 19.8 16.6 19.7 17.7 18.0 tl 0.8 0.5 0.5 0.6 0.3 0.4 0.3 0.3 0.2 0.5 0.5 tm 0.25 0.17 0.31 0.32 0.25 0.29 0.32 0.25 0.27 0.21 0.27 u 4.4 13.3 2.1 6.7 5.5 7.1 7.2 5.5 5.3 4.4 6.2 v 42 35 113 62 50 29 43 42 48 33 53 w 3 4 1 2 1 1 1 1 1 3 2 y 14.6 9.8 21.7 20.1 14.8 17.2 17.9 17.2 16.5 13.0 15.1 yb 1.91 1.23 2.24 2.06 1.62 2.02 2.21 1.88 1.76 1.53 1.70 zn 36 23 50 47 35 30 29 37 43 31 36 zr 141 157 156 162 128 153 172 167 178 143 138 table 3 whole rock trace element composition (ppm) of the samples. 157esenli et al.: zeolitization of tuffaceous rocks in the keşan region, thrace, turkey parison of mordenites from the lower and upper levels. cation contents change from [ca1.0 mg1.5 na1.2 k2.7] for the lower level mordenites (sample 1) to [ca2.0 mg2.1 na3.3 k0.5] for the upper level mordenites (sample 19). mordenites of the lower level are poor in na and ca and rich in k, whereas mordenites of the upper levels are poor in k and rich in na and ca. morphological properties of these mordenites from the lower level, even the middle levels (samples 6 and 11), show a fibrous habit and mordenites from the upper level are needle-like in shape (figs. 4a and b). consequently, fibrous mordenites are rich in k and needle-like mordenites are rich in ca and na in the keşan region. stocia et al. (1992) showed that structural changes of mordenite-group minerals are due to chemical and thermal differentiation. hawkins (1981) also concluded that mordenites had a more tabular than fibrous morphology when they tended to be rich in ca. likewise, ca-rich mordenites in the şile region (nw i̇stanbul, turkey) displayed prismatic crystals with c-elongation similar to those of epistilbites (esenli̇ et al., 1997b). in spite of the fact that typically tabular mordenite have not been found in the keşan samples, the relationship between the chemistry and morphology of fibrous and needle-like mordenites from the sw keşan supports these findings. furthermore, rudolf & garces (1994) reported the relationships between si/al ratios, c-dimensions and x-ray patterns of mordenites. but, the x-ray patterns and si/ al ratios of the keşan mordenites collected from different stratigraphic levels do not show any significant difference. xrd patterns of mordenite are slightly broaded (fig. 2b). the d-spacing values (ǻ) of principal reflections of all studied mordenites are 3.49, 3.22, 9.15, 4.00, 3.40, 6.65 and 4.54. heulandite-group minerals were found to have developed directly from volcanic glass. although, the existence of heulandite–clinoptilolite minerals in the keşan fig. 3 classification of samples based on zr/tio2 vs. nb/y diagram of winchester & floyd (1977). sample 1 6 6 6 9 11 11 14 19 19 (mineral) (m) (m) (m) (h–c) (a) (m) (h–c) (a) (m) (h–c) si 37.45 37.68 37.64 28.07 33.87 36.83 29.80 34.92 37.38 27.87 al 9.57 9.93 9.60 7.65 14.94 10.24 6.32 14.50 8.57 8.07 fe 1.25 0.74 1.19 0.37 0.06 0.61 0.23 0.32 1.31 0.14 ti 0.22 0.16 0.09 0.09 – 0.09 – – 0.22 0.14 mg 1.50 0.90 0.82 0.90 0.38 1.19 0.77 – 2.13 1.22 ca 0.97 1.74 1.85 2.13 0.22 1.83 1.09 0.16 2.03 1.91 k 2.69 1.37 2.32 0.60 0.06 0.98 0.50 0.06 0.50 0.37 na 1.19 1.99 1.25 0.70 10.27 2.13 0.86 10.34 3.25 0.69 si/al 3.91 3.79 3.92 3.67 2.27 3.60 4.72 2.41 4.36 3.45 na+k/mg+ca 1.57 1.27 1.34 0.42 1.03 0.73 0.90 0.34 error % 22.6 23.4 21.1 8.9 30.1 18.5 28.9 38.2 18.1 12.1 table 4 the unit-cell compositions of heulandite–clinoptilolite (h–c), mordenite (m) and analcime (a). 158 geologia croatica 58/2 samples were determined by xrd studies, their typical crystal habit (monoclinic plate) was not observed in sem studies. these grains are generally anhedral in shape and about 5 μm long (fig. 4e). the average structural formulae of the keşan heulandite-group zeolites was calculated on the basis of 72 oxygen to [ca1.7 mg1.0 na0.8 k0.5] [al7.4 si28.6 o72] ·24h2o. this formula is close to the clinoptilolite-ca referred by coombs et al. (1997). si/al ratios of the keşan heulandite-group zeolites range from 3.45 to 4.72 and their average value is 3.95 (table 4). according to this ratio, some of the analyzed heulandite-group zeolites are clinoptilolite while the others can be classified as heulandite. their (na+k)/(ca+mg) ratios have an average value of 0.50 and range from 0.34 to 0.73. analcimes were observed by both optical microscopy and sem as idiomorphous and hypidiomorphous crystals, mainly bedded in volcanic glass (fig. 4f). these minerals were generally below 0.05 mm in size. no transformation from any phenocrysts and zeolite mineral to analcime was observed; it occurred directly from volcanic glassy materials. the xrd patterns of a b c d e f fig. 4 photomicrographs of zeolite minerals: (a) fibrous mordenites in the sample 1; (b) needle-like mordenites in the sample 19; (c) needlelike mordenites with radial habit in sample 19; (d) fibrous mordenites which are growing from volcanic glass in the sample 1; (e) mordenites over the anhedral heulandite-group minerals in sample 6; (f) analcime in volcanic glassy material in sample 14. 159esenli et al.: zeolitization of tuffaceous rocks in the keşan region, thrace, turkey analcime are very sharp (fig. 2a) and spacing values (ǻ) of the most important lines are 3.43, 5.65, 2.93 and 2.50 in order of their relative intensities. the chemistry of analcime (table 4) was slightly consistent with the typical unit-cell formula reported in the literature (mumpton, 1981; gottardi & galli, 1985). the keşan analcimes had a high content of si and lesser content of al and na. the average value of the si/al ratio of two analcime grains was 2.34. 4.3. occurrence the relative abundance and stratigraphic distributions of authigenic minerals of the pyroclastic-rich zone of the mezardere formation are shown in fig. 5. mordenite and heulandite–clinoptilolite are the most and the least abundant zeolite minerals in this zone, respectively (table 1 and fig. 5). these two minerals exist together at a level where analcime is absent. there are two separate analcime-rich levels in the middle parts of the zone (fig. 5). smectite is associated with all zeolite minerals and its abundance increases upward. opal-ct is observed in minor amounts in association with mordenite and heulandite-group zeolites in the middle levels. no petrographic evidence is found to suggest the time relationships for the occurrences of opal, smectite and zeolites. authigenic quartz commonly occurs with analcimes. zeolitic tuffaceous rocks in the keşan region are interbedded with lower oligocene sediments of lacustrine and shallow marine environments. zeolitization is limited only to pyroclastics and not found in epiclastics. the recurrent alternate horizons of mordenite (+heulandite–clinoptilolite) and analcime in about a 30 m thick zone could not be explained by variation of marine water chemistry. it is difficult to explain how major changes of shallow marine water composition can take place within short time intervals. therefore, the zeolitization in the keşan seems not to be developed in a marine environment. moreover, the formation of analcime and mordenite in different levels could not be related to the chemistry of the host rock. chemical composition and petrographic characteristics of rocks where the zeolitization took place show no distinct variation with stratigraphy. zeolitization probably took place in a lacustrine environment, being exposed to an open hydrological system. no lateral zonation of authigenic minerals was observed throughout the area (between the kızkapanı and karahisar localities). this implies that zeolitization took place at constant conditions laterally. but, as seen in fig. 5, vertical mineralogical zonation was clearly observed in the field. the vertical variation of petrographic and mineralogical composition of the tuffaceous rocks (fig. 5) can be examined in a quarry in the kızkapanı area. but, the exposures of tuffaceous rocks are limited in the karahisar area. in this area, mordenite-rich levels correspond stratigraphically to the mordenite-rich upper levels of the kızkapanı section (fig. 5). however, the lower levels of the karahisar section have not been observed in the field, and thus no information was available. taking only the upper levels of pyroclastics in two areas into consideration, there is no evidence showing the lateral variation in zeolitization. during zeolitization, the fluid chemistry probably changed over short time intervals. hydrological and fig. 5 stratigraphically, relative abundances of authigenic minerals in the study area (sw keşan). 160 geologia croatica 58/2 mineralogical boundaries have also changed as they were controlled by climatic parameters. conditions in open hydrological systems have probably changed to those of a closed lacustrine environment causing alkali enrichment in the water. two analcime-rich levels must have developed due to these changes. such environmental changes took place during the oligocene–miocene in the thrace region, especially in the south thrace (turgut et al., 1983). in oligocene time, the chemistry of pore water and ground water was suitable for the development of mordenites (stratigraphically lower level in fig. 5) in the keşan region (actually sw keşan). towards the end of this period, first smectite and then heulandite–clinoptilolite became associated with mordenite. later, the following products formed sequentially: (a) analcime, (b) mordenite (mordenite+heulandite–clinoptilolite+ smectite+opal-ct), (c) second analcime, and finally (d) a longer mordenite formation period. still later, smectite and heulandite–clinoptilolite association formed with mordenite. zeolitization in the keşan region have been controlled by the variation of water chemistry through time. 5. conclusions in se keşan the stratigraphically lower zone of the tuffaceous rocks of oligocene age have undergone zeolitic alteration. this process has created a vertical zone of different zeolite minerals. parent material, mainly volcanic glass, has been transformed to zeolite minerals by the action of fluids probably in an open hydrological regime. however, there must be several intervals affected by various parameters during this episode. thus, analcimeand mordenite(+heulandite–clinoptilolite)-rich levels formed repeatedly in the study area. the stratigraphic sequence of zeolite mineral paragenesis of at 30 metre thick tuffaceous zone can be summarized as: (mordenite) → (mordenite+heulandite–clinoptilolite) → (analcime) → (mordenite+heulandite–clinoptilolite) → (mordenite) → (analcime) → (mordenite) → (mordenite+heulandite–clinoptilolite). this mineralogical sequence reflects the changes in hydrological systems and chemistry of waters during the zeolitization processes and emphasized the variation in geological environments. in the early oligocene changes in the climate and depth of the lake water must have taken place in the sw thrace. the mineralogical data presented in this paper agree with previously reported geological observations in thrace by turgut et al. (1983, 1991). acknowledgements the authors thank dr. attila kilinç who read and improved the text. comments and review by professor darko tibljaš and professor vladimir bermanec are gratefully acknowledged. 6. references alietti, a. (1972): polymorphism and crystal-chemistry of heulandites and clinoptilolites.– american mineralogist, 57, 1448–1462. alietti, a., brigatti, m.f. & poppi, l. (1977): natural ca-rich clinoptilolites (heulandite of group 3): new data review.– neues jahrbuch für mineralogie–monatshefte, h11, 493–501. barth-wirshing, u. & holler, h. (1989): experimental studies on zeolite formation conditions.– european journal of mineralogy, 1, 489–506. boles, j.r. (1972): composition, optical properties, cell dimensions and thermal stability of some heulanditegroup zeolites.– american mineralogist, 57, 1463–1493. boles, j.r. (1988): occurrences of natural zeolites. present status and future research.– in: kallo, d. & sharry, h.s. (eds.): occurrence, properties and utilization of natural zeolites. akademiai kiado, budapest, 3–18. coombs, d.s., alberti, a., armbruster, t., artioli, g., colela, c., galli, e., grice, j.d., liebau, f., mandarino, j.a., minato, h., nickel, e.h., passaglia, e., peacor, d.r., quartieri, s., rinaldi, r., ross, m., sheppard, r.a., tillmans, e. & vezzalini, g. (1997): recommended nomenclature for zeolite minerals: report of the subcommittee on zeolites of the international mineralogical association, commission on new minerals and mineral names.– the canadian mineralogist, 35, 1571–1606. ercan, t., türkecan, a., gui̇llou, h., satir, m., sevi̇n, d. & şaroglu, f. (1998): marmara denizi çevresindeki tersiyer volkanizmasının özellikleri [tertiary volcanism around the sea of marmara – in turkish].– mta bulletin, 120, 199–221. esenli̇, f., uz, b., eren r.h., coban, f., manav, h., yavuz, o. & kumbasar, i. (1997a): alteration products of pyroclastic rocks in thrace, turkey.– in: papunen, h. (ed.): proceeding of the 4. biennial sga meeting – mineral deposits, turku, 713–716. esenli̇, f., uz, b. & kumbasar, i. (1997b): mordenite type zeolite occurrence in the upper cretaceous volcanics of şile region, i̇stanbul–turkey.– geological bulletin of turkey, 40, 43–49. genç, ş.c. (1998): evolution of the bayramiç magmatic complex, northwestern anatolia.– journal of volcanology and geothermal research, 85, 233–249. godovikov, a. (1985): mineralogy.– mir, moscow, 582 p. gottardi, g. & galli, e. (1985): natural zeolites.– springer verlag, berlin, 409 p. hawkins, d.b. (1981): kinetics of glass dissolution and zeolite formation under hydrothermal conditions.– clays and clay minerals, 29, 331–340. hay, r.l. (1981): geology of zeolites in sedimentary rocks.– in: mumpton, f.a. (ed.): mineralogy and geology of natural zeolites. reviews in mineralogy, mineralogical society of america, washington d.c., 53–64. i̇çöz, s. & türkmenoglu, a. (1997): eosen-oligosen yaşlı klastiklerin (keşan, trakya) mineralojik, petrografik ve jeokimyasal incelenmesi [the mineralogic, 161esenli et al.: zeolitization of tuffaceous rocks in the keşan region, thrace, turkey petroghraphic and geochemical investigation of eocene– oligocene clastics, keşan, thrace – in turkish].– in: işik, i̇. (eds.): proceeding of the national clay symposium. kütahya, 37–48. iijima, a. & utada, m. (1966): zeolites in sedimentary rocks with reference to the depositional environments and zonal distribution.– sedimentology, 7, 327–357. kitsopulos, k.p. (1997): the genesis of a mordenite deposit by hydrothermal alteration of pyroclastics on polyegos island, greece.– clays and clay minerals, 45, 632–648. koop, k.o., pavoni, n. & schindler, c. (1969): geologie thrakiens. das ergene becken.– beihefte zum geologischen jahrbuch, 76, 171 p. mason, b. & sand, l.b. (1960): clinoptilolite from patagonia. the relationship between clinoptilolite and heulandite.– american mineralogist, 45, 341–350. mumpton, f. (1981): natural zeolites.– in: mumpton, f.a. (ed.): mineralogy and geology of natural zeolites. reviews in mineralogy, mineralogical society of america, washington d.c., 1–15. okay, a.i. & tüysüz, o. (1999): tethyan sutures of northern turkey.– in: durand, b., jolivet, l., horvath, f. & seranne, m. (eds.): the mediterranean basins: tertiary extension within the alpine orogen. geological society of london, spec. publ., 156, 475–515. passaglia, e. (1975): the crystal chemistry of mordenites.– contributions to mineralogy and petrology, 50, 65–77. pe-piper, g. (2000): mode of occurrence, chemical variation and genesis of mordenite and associated zeolites from the mordem area, nova scotia, canada.– the canadian mineralogist, 38, 1215–1232. rudolf, p.r. & garces, j.m. (1994): rietveld refinement of several structural models for mordenite that account for differences in the x-ray powder pattern.– zeolites, 14, 137–146. şengör, a.m.c. & yilmaz, y. (1981): tethyan evolution of turkey: a plate tectonic approach.– tectonophysics, 75, 181–241. stocia, a.d., tarina, v., russu, r. & gherghe, g. (1992): structural changes in mordenites revealed by two dimensional fourier synthesis of x-ray powder diffraction patterns.– zeolites, 12, 706–709. ternek, z. (1949): keşan, korudağ bölgesinin jeolojisi [the geology of keşan–korudağ region – in turkish].– unpubl. phd thesis, i̇stanbul university, i̇stanbul, 78 p. turgut, s., si̇yako, m. & di̇lki̇, a. (1983): trakya havzasının jeolojisi ve hidrokarbon olanakları [the geology of thrace basin and hydrocarbon resources – in turkish].– geological bulletin of turkey, 4, 35–46. turgut, s., türkaslan, m. & peri̇nçek, d. (1991): evolution of the thrace sedimentary basin and its hydrocarbon prospectivity.– european assoc. petroleum geoscientists, spec. publ., 1, 415–437. winchester, j.a. & floyd, p.a. (1977): geochemical discrimination of different magma series and their differentiations products using immobile elements.– chemical geology, 20, 325–340. yilmaz, y. & polat, a. (1998): geology and evolution of the thrace volcanism, turkey.– acta vulcanologica, 10, 293–303. yilmaz, y., tüysüz, o., yi̇gi̇tbaş, e., genç, ş.c. & şengör, a.m.c. (1997): geology and tectonic evolution of the pontides.– in: robinson, a.g. (ed.): regional and petroleum geology of the black sea and surrounding region. aapg memoir, 68, 183–226. manuscript received september 29, 2004. revised manuscript accepted november 11, 2005. 162 geologia croatica 58/2 schlagintweit et al.indd 1. introduction during late triassic times, the northern calcareous alps were part of a wide shelf exhibiting characteristic margin-parallel facies zonation located at the western end of the tethyan ocean (e.g. tollmann, 1976, 1985; gawlick, 2000 with references; mandl, 2000). the norian–rhaetian dachstein limestone is generally divided into the bedded lagoonal dachstein limestone and the dachstein reefal limestone, i.e. protected internal lagoonal facies and typical outer platform settings with reefal and peri-reefal facies (e.g. zankl, 1971; lein, 1987; gawlick, 2000 – fig. 4). the norian bedded dachstein limestone is typically represented by so-called lofer cycles in the central platform area (fischer, 1964; enos & samankassou, 1998). within the “reef-limestones”, corals and calcarcoptocampylodon? rhaeticus n.sp., a new problematic microfossil (“incertae sedis”) from the rhaetian dachstein limestone of the northern calcareous alps (germany, austria) felix schlagintweit1, sigrid missoni2 and hans-jürgen gawlick2 eous sponges are the main frame-builders (zankl, 1969; senowbari-daryan, 1990). famous localities of dachstein reef-limestones within the northern calcareous alps include for example, the hohe göll (zankl, 1969) and the gosaukamm (wurm, 1982). within any shallow water platform carbonates, the main important microfossil groups (calcareous algae and benthic foraminifera) show a well pronounced facies sensitivity enabling the differentiation of typical facies-dependent assemblages (senowbari-daryan & schäfer, 1979). the calcareous algae belonging to the dasycladales, are discussed in the works of flügel (1975), piros et al. (1994), senowbaridaryan & schäfer (1979) and senowbaridaryan & flügel (1993). in the latter work, for example, 11 species of dasycladales including 2 taxa indicated to be restricted to the rhaetian interval have been listed for the alpine norian–rhaetian platform carbonates. recent investigations however, showed that present knowledge of the algal inventory of the dachstein limestone is still far from being complete (schlagintweit et al., 2001). in the framework of the ongoing investigations a new problematic microfossil has been detected in great abundance in biosparitic limestones (grainto rudstones), and is described herein as coptocampylodon? rhaeticus n.sp. besides several illustrations in the alpine literature, the material treated in the present paper comes from the kehlstein near berchtesgaden (germany), the area west of lofer (austria) and the rofan mountains, tyrol (austria). the rhaetian dachstein limestone nearby and south of the kehlstein house (samples ber 101) has been chosen as the type-locality. 2. geological setting mount kehlstein in the berchtesgaden alps tectonically belongs to the higher tirolic nappe (frisch & gawlick, 2001, in press) and was part of the rhaetian lagoonal area south of the kössen basin (golebiowski, 1990, 1991). the sedimentary sequence consists of norian lagoonal dachstein limestone at the base, followed by marls and carbonates of the kössen formation (braun, 1998 – cum lit.) geologia croatica 55/2 107–119 2 figs. 2 pls. zagreb 2002 key words: microproblematica, calcareous algae, upper triassic, dachstein limestone, northern calcareous alps, austria, germany. 1 lerchenauerstrasse 167, d-80935 munich, germany; e-mail: ef.schlagintweit@t-online.de 2 university leoben, institute for geosciences, prospektion and applied sedimentology, peter-tunner-str. 5, a-8700 leoben, austria. abstract a new problematic microfossil is described as coptocampylodon? rhaeticus n.sp. from the rhaetian dachstein limestone of the northern calcareous alps. the new species is composed of a long cylindrical and an irregular rounded body, both showing narrow axial cavity. it is similar to coptocampylodon? elliotti radoičić 1969 from the cenomanian of montenegro, but lacks the longitudinal grooves in the cylindrical part. in the alpine dachstein limestone it has been detected at several localities where it occurs as an abundant constituent of biosparitic limestones along with the benthic foraminifera triasina hantkeni majzon, aulotortus sinuosus weynschenk, duostominidae and dasycladales griphoporella curvata (gümbel) and diplopora adnetensis flügel. 108 geologia croatica 55/2 109schlagintweit, missoni & gawlick: coptocampylodon? rhaeticus n.sp... and rhaetian lagoonal dachstein limestone. on the top of the sequence, late jurassic mass-flow deposits occur with components of dachstein limestone, late jurassic shallow water limestones and carbonates of the late jurassic oberalm formation (lebling, 1935; plöchinger, 1955; braun, 1998 – cum lit., new unpublished results). most of the samples derive from the rhaetian dachstein limestone or from dachstein limestones near the norian/rhaetian boundary (ber 101–1, ber 101–4) in the southern area of mount kehlstein or near the top of kehlstein (fig. 1). the sample ber 101–12 represents a clast in an upper jurassic mass-flow deposit with allochthonous shallow water microfossils deposited on top of the rhaetian dachstein limestone in the northern part of the kehlstein. besides the type-locality, the new species has been detected from the following localities: – northern side of the lofer kalvarienberg at 960 m an (forest road), in the westward continuation of the southern rim of the kössen basin; sample ks 79a, d; rhaetian backreef and lagoonal dachstein limestone (golebiowski, 1991); – rofan mountains, tyrol; sample rf 1–01; pebble in late jurassic mass-flow deposits; – unken valley; mass-flow deposits (“schwarzbergklamm-brekzie”) of the tauglboden formation deriving from the trattberg rise (garrison & fischer, 1969); – hohes brett, southern rim, south of the jägerkreuz; rhaetian slope sediments (zankl, 1969; braun, 1998) (sample ber 86/7); – north of pass lueg on the street b 162 from werfen to golling; samples y 11, y 7a, kö6); rhaetian dachstein limestone intercalated by marls of the kössen formation (wegerer & gawlick, 1999); fig. 1 tectonic map of the middle part of the northern calcareous alps and sample locations of the complete sedimentary sequences of rhaetian dachstein limestone in the kehlstein and lofer area (after frisch & gawlick, 2001, in press). 108 geologia croatica 55/2 109schlagintweit, missoni & gawlick: coptocampylodon? rhaeticus n.sp... – lake traunsee, south ebensee; samples po 10, 12, 16, 22; eb 7, pr 6 97, eb 11 pr 11, eb 24; rhaetian lagoonal dachstein limestone (wegerer & gawlick, 1999). 3. systematics it was elliott (1963) who established the new genus coptocampylodon with the type-species coptocampylodon lineolatus n.sp. from the lower cretaceous of the middle east and borneo. the generic diagnosis of coptocampylodon was indicated as follows: “small solid cylindrical bodies, longer axis gently curved or irregular, circular in cross-section but deeply incised by longitudinal grooves, ends irregularly rounded.” as has been discussed by elliott, these microfossils incertae sedis have previously been assigned to acicularian spicules. in conclusion, however, elliott suggested that “coptocampylodon comprises the skeletal remains of a small octocoral in which horny and calcareous joints alternated”. almost two years later, a second representative was introduced by patrulius (1965) as coptocampylodon fontis from the urgonian limestones (barremian–aptian) of romania, characterized by the frequent occurrence of an axial canal that is lacking in the typespecies. unfortunately, patrulius did not designate a holotype, but syntypes. based on coptocampylodon fontis, dragastan (1967) established the new genus carpathoporella with the type-species carpathoporella occidentalis assumed to belong to the dasycladales, unfortunately also without the designation of a holotype. later, radoičić (1969) established the new species coptocampylodon elliotti from the cenomanian of montenegro. the author considered carpathoporella occidentalis dragastan as the younger synonym of coptocampylodon fontis. as regards the type-species of coptocampylodon, c. lineolatus elliott 1963, it has been assigned to a non-vertebrate coprolith (cuvillier et al., 1969). dragastan (1989) provided the new combination carpathoporella fontis (patrulius) and chose a holotype from the authors material. in all these taxa, the presence or absence of an axial hollow has been the reason for some of the discussion. following patrulius (1965) there are representatives of c. fontis some of which show an axial hollow and others that do not. for example, basson & edgell (1971) reported and figured both, coptocampylodon lineolatus elliott and c. fontis from the lower cretaceous of lebanon co-occuring in the same sample. the same observation can also be made with the new species coptocampylodon? rhaeticus n.sp. with specimens with and without a central hollow. the latter are interpreted as sections through the closed distal parts. basson & edgell (1971, p. 420) discuss another interpretation, that “there have been varying degrees of calcification of the thallus and the central canal”. star-like sections have been referred to carpathoporella? sp. by masse & arnaud-vanneau (1999, pl. 1, fig. 4–6) from the lower cretaceous of the mid-pacific mountains, deep sea drilling leg 143, west of hawaii. following radoičić (1969), the authors remark on similarities to transverse sections of the distal ramifications of the dasycladalean triploporella? neocomiensis radoičić (without axial canal) that, for example, have been figured by sotak & misik (1993, pl. 1, figs. 6–11). equivalent fragments have been described as “microproblematicum 3” from the upper barremian urgonian limestones of the northern calcareous alps (schlagintweit, 1991: p. 29, fig. 13) and a similar interpretation has been assumed. barattolo & de castro (1991, p. 54) assume that the remains of coptocampylodon cf. elliotti from the lower cretaceous of southern italy “could represent tufts of 5–6 trichophorous secondary branches of a selliporella-like dasyclad”. coptocampylodon fontis patrulius has been removed from the dasycladales by jaffrezo (1974), followed by bassoullet et al. (1978). some affinities with charophytes have been supposed by dragastan (1989), a view that we cannot follow for facies considerations since c. fontis is typical of well-agitated outer platform settings, for example in the urgonian limestones of the northern calcareous alps (schlagintweit, 1991) and also the outer platform facies of the rhaetian dachstein limestones with coptocampylodon? rhaeticus n.sp. (see below). radoičić (1969), cautiously followed by masse & poignant (1971), and luperto sinni (1979), stated the synonymy between carpathoporella occidentalis dragastan and coptocampylodon fontis patrulius. granier & deloffre (1994) also excluded the genus coptocampylodon elliott 1963 with the type-species c. lineolatus from the dasycladales. the cenomanian species is questioned regarding its generic position and treated as c.? elliotti radoičić. as already remarked by dragastan (1989 – p. 43), in the original description of coptocampylodon elliotti no holotype has been designated by radoičić (1969). later, in the framework of the inventory of mesozoic dasycladales provided by granier & deloffre (1994), a holotype for coptocampylodon? elliotti was designated by radoičić thus remaining the only species tentatively referred to the genus coptocampylodon elliott. regarding the genus carpathoporella dragastan, it is treated as “nom. nud.” by granier & deloffre (1994) due to the lack of a holotype, and the repeated establishment of the genus carpathoporella dragastan 1989 is also treated as “nom. nud.”, since being founded on another species, coptocampylodon fontis. a detailed synonymy is provided below for coptocampylodon fontis patrulius and coptocampylodon elliotti radoičić. 110 geologia croatica 55/2 111schlagintweit, missoni & gawlick: coptocampylodon? rhaeticus n.sp... genus coptocampylodon elliott, 1963 coptocampylodon fontis patrulius, 1965 *1965 coptocampylodon fontis n.sp. – patrulius, p. 393, textfigs. 1a–0, 2a–f, pl. 1, a–f. 1966 coptocampylodon (?) sp. – luperto sinni: pl. 2, fig. 3, barremian–aptian of s-italy. 1967 carpathoporella occidentalis n. gen., n.sp. – dragastan: 444, pl. 1, figs. 7, 9, pl. 2, figs. 10–16. 1969 coptocampylodon fontis patrulius – radoičić: pl. 1, fig. 2, pl. 2, figs. 1–3, pl. 3, figs. 1–5. 1971 carpathoporella occidentalis dragastan – masse & poignant: 260, pl. 1, fig. 7, hauterivian to lower aptian of the provence area/s france. 1971 carpathoporella occidentalis dragastan – basson & edgell: pl. 4, figs. 6–8, aptian of lebanon. 1972 carpathoporella sp. – fourcade et al.: pl. 4, fig. 1, barremian–aptian of the internal prebetic/ spain. 1973 carpathoporella occidentalis dragastan – bakalova: pl. 2, fig. 7, lower cretaceous lovech urgonian group of bulgaria. 1978 coptocampylodon fontis patrulius – babić & gušić: pl. 2, fig. 4, barremian–albian of mt. ivanščica/croatia. 1979 coptocampylodon fontis patrulius – luperto-sinni: 442, pl. 43, figs. 2–6, 8–10, with synonymy, barremian–aptian of apulia/s italy. 1980 coptocampylodon fontis patrulius – arnaud-vanneau: pl. 112, figs. 5–6, upper barremian urgonian limestones of s france. 1986 coptocampylodon fontis patrulius – mantea & tomescu: pl. 12, figs. 1–6, metaliferi mts. of romania. 1987 carpathoporella fontis (patrulius) – masse & rossi: fig. 5(b), lower aptian of venezuela. 1989 carpathoporella fontis dragastan – dragastan: 40, pl. 17, figs. 2–8, barremian–lower aptian in the carpathian and in the moesian platform/romania (with synonymy, validation and designation of lectotype). 1991 carpathoporella fontis (patrulius) – misik et al.: pl. 5, fig. 6, lower cretaceous carbonate pebbles from the western carpathians. 1991 coptocampylodon fontis patrulius – schlagintweit: 29, pl. 8, figs. 6–8, upper barremian–aptian urgonian limestones of the northern calcareous alps/germany and austria. 1992 coptocampylodon fontis patrulius – masse, arias & vilas: pl. 3, fig. 12, aptian–albian of the prebetic zone/spain. 1993 carpathoporella fontis (patrulius) – sotak & misik: pl. 1, fig. 12, barremian–aptian of the western carpathians. 1994 acicularia sp. – császár et al.: pl. 8, fig. 4, upper barremian–lower aptian of the schratten limestone of vorarlberg/austria. 1994 coptocampylodon? fontis patrulius nom. nud. – granier & deloffre, p. 28. 1995 coptocampylodon fontis patrulius – carras: pl. 54, fig. 7, lower cretaceous of greece. 1999 coptocampylodon fontis patrulius – masse & arnaud-vanneau: 60, pl. 1, figs. 1–3, late hauterivian–barremian of mid-pacific mountains, deep sea drilling leg 143, west of hawaii. 2001 coptocampylodon fontis patrulius – bucur: pl. 10, fig. 2, upper aptian of the resita–moldova noua zone/southern carpathians of romania. coptocampylodon? elliotti radoičić, 1969 *1969 coptocampylodon elliotti n.sp. – radoičić: 199, pl. 4, figs. 1–2, cenomanian of montenegro. 1989 carpathoporella elliotti (radoičić) nov. comb. – dragastan: 43 (not figured). 1991 coptocampylodon elliotti radoičić – barattolo & de castro: pl. 3, fig. 2, aptian of the sorrento peninsula/s italy. 1994 coptocampylodon? elliotti radoičić – granier & deloffre, p. 21, validation with designation of lectotype (not figured). as can be seen from the references cited, coptocampylodon fontis patrulius represents a widespread microfossil occurring within upper jurassic to albian strata, with the greatest distribution in the barremian aptian interval (“urgonian facies”). for coptocampylodon elliotti radoičić, although also established in the sixties as c. fontis, we can only mention the occurrence in southern italy (see synonymy) besides the type-locality in the dinarides. coptocampylodon? rhaeticus n.sp. (pl. i, figs. 1–7; pl. ii, figs. 1–12) 1989 “dasycladacean algae characterized by small spiny thalli” – stanton & flügel: pl. 38, figs. 1–2, 7, pl. 39, figs. 3–4, upper rhaetian “reef”complex of the steinplatte/austria. origin of the name: the species name refers to the stratigraphic occurrences in the rhaetian stage. type-locality: kehlstein area, ök 93 bad reichenhall, 1850 m an, path from the kehlstein house to the hohe göll at the base of late jurassic mass-flow deposits (fig. 1). 110 geologia croatica 55/2 111schlagintweit, missoni & gawlick: coptocampylodon? rhaeticus n.sp... type strata: packstones and grainstones, gray to light brown limestones, m-thick bedded sequence of the lagoonal rhaetian dachstein limestone overlying the kössen beds and the “hauptlithodendronkalk”. the latter was deposited in a transgressive–regressive cycle and approximates the norian–rhaetian boundary (golebiowski, 1991) consisting of massive coralline beds. above the “hauptlithodendronkalk” the lagoonal rhaetian dachstein limestone occurs forming an isolated platform between the koessen basin to the north and the hallstatt area to the south (gawlick, 2000). holotype: cross-section figured on pl. 1, fig. 5, sample ber 101–4a. the material is stored at the “institut for geowissenschaften, universität leoben”. diagnosis: small representative of the genus with a comparably long cylindrical part (“stalk”) with a narrow axial hollow and without marginal outer grooves. rounded part (“head”) with or without an axial hollow and a low number of marginal grooves. description: the new species is composed of a comparably long cylindrical (“stalk”) (e.g. pl. 1, fig. 3) and an irregular rounded body (“head”) (e.g. pl. 1, fig. 6), both showing a relatively narrow central or axial hollow. in the material studied, no specimens were found where both parts were in original mutual contact. that both parts belong to the same taxon, however, is obvious since these always occur in great abundance together (e.g. pl. 2, fig. 10). the solid cylindrical part up to 1.15 mm in length is often slightly curving and shows smooth outer and inner surfaces. in the cylindrical part, the central hollow comprises approximately 30% of the outer diameter. the ball-shaped part shows marginal grooves (mostly 7) at the outer part (e.g. pl. 2, fig. 1). since these do not transect the calcareous skeleton/wall, these cannot be termed pores. the relative diameter of the central hollow is very variable (mostly ~25%) with respect to the outer diameter. it is assumed that those sections, with a very small central hollow are cut more distally, near a closed end. the latter is evidenced by sections without any central hollow (pl. 1, fig. 6). these do not show the grooves, an effect that could be secondary in origin (e.g. abrasion in a high-energy environment). dimensions: see fig. 2. remarks: coptocampylodon? fontis besides being larger (e.g. d = 0.2–0.6 mm, acc. to dragastan, 1989), differs from coptocampylodon? rhaeticus n.sp. in its higher number of marginal grooves (9–15 acc. to dragastan, 1989). moreover these are more regularly of a semicircular shape whereas in c.? rhaeticus they are more irregular often with a more acute inner part. coptocampylodon? rhaeticus n.sp. is very close to c.? elliotti radoičić from the cenomanian of montenegro. in fact, the biometric data of the specimens from the rhaetian dachstein limestone are in the range of the cenomanian species. the main difference is the absence of marginal grooves in the cylindrical part of c.? rhaeticus n.sp. showing a smooth outer surface. these grooves are well developed in c.? elliotti radoičić (radoičić, 1969: pl. 4, fig. 1, pl. 5, fig. 2, pl. 6, figs. 1–4). in c.? elliotti the marginal grooves often show a tendency to become externally closed as already remarked by dragastan (1989, p. 43). in c.? rhaeticus n.sp. the groves usually display a clear concave shape (e.g. pl. 1, fig. 5) and only occasionally become very narrow (e.g. pl. 1, fig. 6, left specimen). fig. 2 dimensions and reconstruction of coptocampylodon? rhaeticus n.sp. 112 geologia croatica 55/2 113schlagintweit, missoni & gawlick: coptocampylodon? rhaeticus n.sp... facies: – oolitic grainstones: these limestones are finegrained and very well sorted consisting mainly of ooids that are built up around small bioclasts. here coptocampylodon? rhaeticus n.sp. is very abundant and is associated with textulariids, involutinids, nodosariids (austrocolomia? sp.) and trochammina? sp. samples: ber 101/4a to 4d (locality kehlstein near berchtesgaden). – packstones: the overall thin-section appearance clearly indicates that this microfacies is closely related to the described oolithic grainstones. thus, components are directly comparable. there are some larger echinoid fragments irregularly distributed in the sediment resulting in a somewhat poorer grade of sorting. samples: ber 101/4a (locality kehlstein near berchtesgaden). – grainstones to packstone with a typical bimodal sorting: the fine-grained portion of this microfacies type is comparable to the above described oolitic grainstones. within this, larger components consisting of intraclasts, bioclasts (echinoids, gastropods, corals) and the larger tests of the triasina hantkeni majzon are dispersed. besides rare coral fragments, influences from the reef facies are present with the scattered remains of alpinophragmium perforatum flügel (flügel, 1967; schäfer & senowbari-daryan, 1978). according to schäfer & senowbari-daryan (1978), triasina hantkeni is well distributed in the algal–foraminiferal detritus facies (“algen–foraminiferen–detritus–fazies”). additionally, there are also fragments of udoteacean algae. samples: ber 101/6, 101/1a (locality kehlstein near berchtesgaden). – rudstone to bioclastic packstone: large clasts of corals, gastropods and the dasycladalean diplopora adnetensis flügel, 1975 are closely packed within a sparitic matrix. foraminifera are present with some involutinids and triasina hantkeni majzon, 1954. according to flügel (1975), d. adnetensis, originally described from the upper rhaetian reef limestone of adnet near hallein/salzburg, typically occurs with corals in the back-reef facies. sample: ber 101/12 (locality kehlstein near berchtesgaden). remains of coptocampylodon? rhaeticus n.sp. within identical microfacies of upper triassic platform carbonates have already been figured in the alpine literature but without concrete identification: – schott (1984): pl. 34, fig. 6 (middle left), biopelmicrite to pelmicrite (mf type b 5), upper rhaetian “reef limestone” brünnstein–auerbach region/lower inn valley. – matzner (1986): pl 8, fig. 11, oolitic packstone– grainstone (mf–6), transition from the dachstein reef limestones to the zlambach formation; locality: “am kleinen zwicker”, steiermark/austria. – böhm (1986): pl. 34, fig. 2 (grapestone facies) and fig. 5 (oolite with triasina hantkeni and trochammina sp.); locality: grimming, steiermark/austria. concerning the occurrences at grimming, böhm (1986) notes, that the oolitic facies only is reported from the rhaetian “when no reef was present to shelter the lagoon and ooid bar could develop”. the well-agitated facies types with remains of coptocampylodon? rhaeticus n.sp. figured by matzner (1986) and böhm (1986) are directly comparable to the material presented here. from the upper rhaetian “reef”-complex of the steinplatte/austria, stanton & flügel (1989) were the first to recognize the specimens as “dasycladacean algae characterized by small spiny thalli”. they are abundant in their “microfacies c 12” that “comprises the strata overlying the relatively massive mound facies” (capping facies) ascribed to a platform margin environment (stanton & flügel, 1989: p. 38). stratigraphy: taking into account the occurring faunal and floral elements, our samples with coptocampylodon? rhaeticus n.sp. can be referred to the rhaetian (e.g. grgasović, 1997: triasina hantkeni taxonrange-zone; de castro, 1990; senowbari-daryan & flügel, 1993). this determination is also supported by evidence from conodonts (sample ber 101–2: misikella posthernsteini kozur & mock, conodont colour alteration index 1.0 – see also braun, 1998) from the kössen formation at the mount kehlstein, which at kehlstein directly underlies the rhaetian dachstein limestone. in the western continuation, west of lofer, the rhaetian dachstein limestone occurs over marls and coral limestones of the koessen formation (not proven by conodonts) in the same sedimentary position as at mount kehlstein. to the west, coptocampylodon? rhaeticus n.sp. occurs in the steinplatte area in the rhaetian dachstein limestone (stanton & flügel, 1989). in the whole area some rhaetian dachstein limestones with coptocampylodon? rhaeticus n.sp. occur as components within late jurassic mass-flow deposits (kehlstein area, schwarzbergklammbrekzie and rofan mountains) eroded from nearby topographic rises (trattberg rise, e.g. kehlstein) due to the closure of the tethys ocean in jurassic times (gawlick et al., 1999 with references). 4. conclusions the calcitic “bodies“ of the microfossil incertae sedis coptocampylodon? rhaeticus n.sp. are very abundant and widespread in the rhaetian dachstein limestone and the “upper rhaetian reef limestone” of the northern calcareous alps characterizing high-energy outer platform to platform margin facies. its systematic position so far remains uncertain. the interpretation as pos112 geologia croatica 55/2 113schlagintweit, missoni & gawlick: coptocampylodon? rhaeticus n.sp... sible secondary ramifications of triploporella species such as t.? neocomiensis (radoičić, 1969), assumed by previous workers for cretaceous coptocampylodons has to be rejected due to the findings in the rhaetian. the calcareous remains obviously do not represent single individuals but parts representing an unknown function of a larger organism of unknown systematic position. the determination of coptocampylodon? rhaeticus n.sp. as a facies dependent fossil is a good aid for determining the palaeogeographic position of some outcrops in the late triassic of the northern calcareous alps. this palaeogeography was destroyed by the later tectonic shortening (jurassic to eocene) with polyphase nappe formation and in later times by lateral tectonic extrusion. during these processes blocks moved towards the north and east out of their original palaeogeographic position. for reconstruction of the late triassic palaeogeography it is necessary to determine facies zones by clear stratigraphic data. thus, the occurrence of coptocampylodon? rhaeticus n.sp. in the rhaetian dachstein limestones may help in the reconstruction of the original late triassic palaeogeography. pebbles of rhaetian dachstein limestone with coptocampylodon? rhaeticus n.sp. in late jurassic massflow deposits show the destruction of the late triassic palaeogeography since the late jurassic and allow the reconstruction of the present day eroded trattberg rise. acknowledgements prof. dr. l. krystyn (vienna) determined the conodonts. financial support of the fwf project p–14131– tec is acknowledged. we are grateful to the reviewers, tonći grgasović and branko sokač for their helpful suggestions for the improvement of the present paper. thanks to julie robson for assistance with the english language. 5. references arnaud-vanneau, a. (1980): l´urgonien du vercors septentrional et de la chartreuse.– geologie alpine, mém. 11 (3 volumes), 874 p., grenoble. babić, l. & gušić, i. (1978): review of fossils from the clastic complex with “ophiolites” of mt. ivanščica and their stratigraphic importance.– geol. vjesnik, 30/1, 1–19, zagreb. bakalova, d. (1973): calcareous algae from the lower cretaceous in northern bulgaria.– bull. geol. inst., ser. paleont., 22, 89–90 (english summary), sofia. barattolo, f. & de castro, p. (1991): site 1 – early cretaceous of monte faito.– in: barattolo, f., de castro, p. & parente, m. (eds.): field trip guide book, 5th int. symp. on fossil algae, 47–55. basson, p.w. & edgell, h.s. (1971): calcareous algae from the jurassic and cretaceous of lebanon.– micropaleontol., 17/4, 411–433, london. bassoullet, j.-p., bernier, p., conrad, m.a., deloffre, r. & jaffrezo, m. (1978): les algues dasycladales du jurassique et du crétacé.– géobios, mém. spéc., 2, 330 p. böhm, f. (1986): der grimming: geschichte einer karbonatplattform von der obertrias bis zum dogger (nördliche kalkalpen).– facies, 15, 195–232. braun, r. (1998): die geologie des hohen gölls. torrener–joch–zone/jenner/hoher göll eine durch kontinent/ kontinent–kollision ausgelöste gleitdecke in den tauglbodenschichten (mittlerer oberjura) der berchtesgadener alpen.– forschungsbericht, 40, 192 p., nationalpark berchtesgaden. bucur, i.i. (2001): lower cretaceous algae of the resita– moldova noua zone.– in: bucur, i.i., filipescu, s. & sasaran, e. (eds.), field trip guide, 4th regional meeting of ifaa, 137–166, cluj–napoca. carras, n. (1995): la piattaforma carbonatica del parnasso durante il giurassico superiore – cretaceo inferiore.– unpubl. phd thesis, university of athens, 232 p. császár, g., mehl, d., oberhauser, r. & lobitzer, h. (1994): a comparative study of the urgonian facies in vorarlberg (austria), im allgäu (germany) and in the villany mountains (hungary).– jubiläumsschr. 20 jahre geol. zus. österr.–ung., 2, 145–207, wien. cuvillier, j., bassoullet, j.-p. & fourcade, e. (1969): coprolithes du jurassique et du crétacé d`espagne et de quelques autres régions.– rev. micropaléont., 11/4, 183–190, paris. de castro, p. (1990): studies on the triassic carbonates of the salerno province (southern italy): the croci d´acerno sequence.– bull. soc. geol. it., 109, 187–217. dragastan, o. (1967): alge calcaroase du jurassique superior si cretacicul inferior din muntii apuseni.– st. si cerc. geol. geofiz. geogr., seria geol., 12/2, 441–454, bucarest. dragastan, o. (1989): calcareous algae (new and revised), microproblematicae and foraminiferida of jurassic–lower cretaceous deposits from the carpathian area.– rev. esp. micropaleont., 21/1, 5–65, madrid. elliott, g.f. (1963): problematic microfossils from the cretaceous and paleocene of the middle east.– paleontol., 6/2, 293–300, london. enos, p. & samankassou, e. (1998): lofer cyclothems revisited (late triassic, northern alps, austria).– facies, 38, 207–228, erlangen. fischer, a.g. (1964): the lofer cyclothems of the alpine triassic.– bull. geol. surv. kansas, 169, 107–149, lawrence. flügel, e. (1967): eine neue foraminifere aus den riffkalken der nordalpinen ober-trias: alpinophragmium perforatum n.g., n.sp.– senckenberg. lethaea, 48/5, 381–402, frankfurt a. main. flügel, e. (1975): kalkalgen aus riffkomplexen der alpin– mediterranen obertrias.– verh. geol. b.–a., 2–3 (1974), 297–346, wien. 114 geologia croatica 55/2 115schlagintweit, missoni & gawlick: coptocampylodon? rhaeticus n.sp... fourcade, e., jerez, l., rodriguez, t. & jaffrezo, m. (1972) : el jurasico terminal y el cretacico inferior de la sierra de la muela (provincia de murcia). consideraciones sobre las biozonas con foraminiferos del albense–aptense del sureste de espana.– rev. esp. miropaleont., num. extraord., 30 aniv. e.n. adaro, 215–248, madrid. frisch, w. & gawlick, h.-j. (2001): the tectonic evolution of central northern calcareous alps.– geol. paläont. mitt. innsbruck, 25, 85–87. frisch, w. & gawlick, h.-j. (in press): the nappe structure of the central northern calcareous alps and its disintegration during miocene tectonic extrusion – a contribution to understanding the orogenic evolution of the eastern alps.– int. journ. earth. sci. garrison, r.e. & fischer, a.g. (1969): deep water limestones and radiolarites of the alpine jurassic.– soc. econ. pal. mineral., spec. publ., 14, 20–56, tulsa. gawlick, h.-j. (2000): paläogeographie der obertrias karbonatplattform in den nördlichen kalkalpen.– mitt. ges. geol. bergbaustud. österr., 44, 45–95, wien. gawlick, h.-j., frisch, w., vecsei, a., steiger, t. & böhm, f. (1999): the change from rifting to thrusting in the northern calcareous alps as recorded in jurassic sediments.– geol. rdschau., 87, 644–657. golebiowski, r. (1990): the alpine kössen formation, a key for european topmost triassic correlations. a sequenceand ecostratigraphic contribution to the norian– rhaetian discussion.– albertiana, 8, 25–35, stockholm. golebiowski, r. (1991): becken und riffe der alpinen obertrias. lithostratigraphie und biofazies der kössener formation.– in: nagel, d. & rabeder, g. (eds.): exkursionen im jungpaläozoikum und mesozoikum österreichs. 79–119, wien. granier, b. & deloffre, r. (1994): inventaire critique des algues dasycladales fossils – ii° partie – les algues dasycladales du jurassique et du crétacé.– rev. paléobiol., 12/1, 19–65, geneva. grgasović, t. (1997): upper triassic biostratigraphy and algae from žumberak (croatia).– geol. croatica, 50/2, 201–214. jaffrezo, m. (1974): les algues calcaires du jurassique supérieur et du crétacé inférieur des corbières (2ème partie).– rev. micropal., 17/1, 23–32, paris. lebling, c. (1935): geologische verhältnisse des gebirges um den königs-see.– abh. geol. landesunters. bayr. oberbergamt, 20, 3–46, münchen. lein, r. (1987): evolution of the northern calcareous alps during triassic times.– in: flügel, h.w. & faupl, p. (eds.): geodynamics of the eastern alps. 85–102, deuticke, wien. luperto sinni, e. (1966): microfaune del cretaceo delle murge baresi.– geol. romana, 5, 117–156, roma. luperto sinni, e. (1979): i microfossili del “livello a palorbitolina lenticularis” delle murge baresi.– riv. ital. paleont., 85/2, 411–480, milano. mandl, g.w. (2000): the alpine sector of the tethyan shelf – examples of triassic to jurassic sedimentation and deformation from the northern calcareous alps.– mitt. österr. geol. ges., 92 (1999), 61–77, wien. mantea, g. & tomescu, c. (1986) : geological structure of the central area of the metaliferi mountains, balsa–ardeu–cib zone.– d.s. inst. geol. geofiz., 70–71/5, 129–148, bucarest. masse, j.-p. & arnaud-vanneau, a. (1999): early cretaceous calcareous algae of the mid-pacific mountains.– rev. micropaléont., 42/1, 57–69, paris. masse, j.-p. & poignant, a.-f. (1971): contribution à l´etude des algues du crétacé inférieur provencal. intéret stratigraphique.– rev. micropaléont., 13/4, 258–266, paris. masse, j.p. & rossi, t. (1987): le provincialisme sudcaraibe à l` aptien inférieur. sa signification dans le cadre de l´evolution geodynamique du domaine caraibe et de l´atlantique central.– cretaceous research, 8, 349–363. masse, j.-p., arias, c. & vilas, l. (1992): 4.2. stratigraphy and biozonation of a reference aptian–albian pp. tethyan carbonate platform succession: the sierra del carche series (oriental prebetic zone – murcia, spain).– schriftenr. erdwiss. komm. österr. akad. wiss., 9 (new aspects on tethyan cretaceous fossil assemblages), 201–221, wien. matzner, ch. (1986): die zlambach-schichten (rhät) in den nördlichen kalkalpen: eine plattform–hang–beckenentwicklung mit allochthoner karbonatsedimentation.– facies, 44, 1–104. misik, m., sykora, m. & jablonsky, j. (1991): strihovské zlepence a juhomagurská kordiléra (slovak with english summary).– západné karpathy, sér. geol., 14, 7–72, bratislava. patrulius, d. (1965): coptocampylodon fontis n.sp., microfosil problematic al calcarelor urgoniene din muntii persani.– dari de seama ale sed., lii/1 (1964–1965), 391–394, bucarest. piros, o., mandl, g.w., lein, r., pavlik, w., berczi-makk, a., siblik, m. & lobitzer, h. (1994): dasycladaceen-assoziationen aus triadischen seichtwasserkarbonaten des ostabschnittes der nördlichen kalkalpen.– jubiläumsschrift 20 jahre geol. zusammenarbeit österr.–ung., teil 2, 343–362, wien. plöchinger, b. (1955): zur geologie des kalkalpenabschnittes vom torrener joch zum ostfuß des untersberges; die göllmasse und die halleiner hallstätter zone.– jb. geol. b.–a., 98, 93–144, wien. radoičić, r. (1969): coptocampylodon de certains sédiments jurassiques et crétacés de la yougoslavie.– vesnik zav. geol. geofiz. istr., 27, 195–200, beograd. schäfer, p. & senowbari-daryan, b. (1978): die häufigkeitsverteilung der foraminiferen in drei oberrhätischen riff-komplexen der nördlichen kalkalpen (salzburg, österreich).– verh. geol. b.–a., 2, 73–96, wien. schlagintweit, f. (1991): allochthone urgonkalke im mittleren abschnitt der nördlichen kalkalpen: fazies, paläontologie und paläogeographie.– münchn. geowiss. abh., 20, 1–120. schlagintweit, f., mandl, g.w. & ebli, o. (2001): salpingoporella austriaca n.sp., a new dasycladale (calca114 geologia croatica 55/2 115schlagintweit, missoni & gawlick: coptocampylodon? rhaeticus n.sp... reous alga) from the lower norian dachstein limestone of mount dachstein (northern calcareous alps, austria).– rev. paléobiol., 20/2, 359–365, genève. schott, m. (1984): mikrofaziell-multivariante analyse einer rhäto–liassischen karbonatplattform in den nördlichen kalkalpen.– facies, 11, 229–280. senowbari-daryan, b. (1990): die systematische stellung der thalamiden schwämme und ihre bedeutung in der erdgeschichte.– münchn. geowiss. abh., 21, 1–326. senowbari-daryan, b. & flügel, e. (1993): triassic reefs and platform carbonates in the northern calcareous alps.– alpine algae field trip guidebook, 35 p. (a1), münchen. senowbari-daryan, b. & schäfer, p. (1979): distributional patterns of calcareous within upper triassic patch reef structures of the northern calcareous alps (salzburg).– bull. cent. rech. explor.–prod. elf–aquitaine, 3/2, 811–820, pau. sotak, j. & misik, m. (1993): jurassic and lower cretaceous dasycladalean algae from the western carpathians.– in: barattolo, f. et al. (eds.), studies on fossil benthic algae. boll. soc. paleont. ital., spec. vol., 1, 382–404, modena. stanton, r.j. jr. & flügel, e. (1989): problems with reef models: the late triassic steinplatte “reef” (northern alps, salzburg/tyrol, austria).– facies, 20, 1–138. tollmann, a. (1976): analyse des klassischen nordalpinen mesozoikums. stratigraphie, fauna und fazies der nördlichen kalkalpen.– deuticke, wien, 580 p. tollmann, a. (1985): geologie von österreich, band 2.– deuticke, wien, 710 p. wegerer, e. & gawlick, h.-j. (1999): zur paläogeographie des gebankten obertriassischen dachsteinkalkes im bereich der staufen–höllengebirgs–decke (nördliche kalkalpen).– zbl. geol. paläont., 1998/1-2, 415–434, stuttgart. wurm, d. (1982): mikrofazies, paläontologie und palökologie der dachsteinriffkalke (nor) des gosaukammes, österreich.– facies, 6, 203–296. zankl, h. (1969): der hohe göll. aufbau und lebensbild eines dachstein-riffes in der obertrias der nördlichen kalkalpen.– abh. senckenberg. naturforsch. ges., 519, 1–123, frankfurt a. main. zankl, h. (1971): upper triassic carbonate facies in the northern limestone alps.– in: müller, g. & friedman, g (eds.).: sedimentology of parts of central europe. kramer, frankfurt, 147–185. 116 geologia croatica 55/2 117 plate 1 coptocampylodon? rhaeticus n.sp. from the upper triassic dachstein limestone of the northern calcareous alps 1 grainstone with abundant remains of coptocampylodon? rhaeticus n.sp. locality: kehlstein, thin-section ber 101–12, scale bar = 1 mm. 2 grainstone to rudstone with bimodal grain-size distribution. larger components include debris of corals and dasycladacean algae, e.g. diplopora adnetensis flügel (right side). locality: kehlstein, thin-section ber 101–12, scale bar = 1 mm. 3 poorly washed packstone with sections of coptocampylodon? rhaeticus n.sp. locality: rofan mountains/tyrol, thin-section rf 1–01, scale bar = 0.5 mm. 4 grainstone with coptocampylodon? rhaeticus n.sp. and involutinid foraminifera. locality: kehlstein, thin-section ber 101–1a, scale bar = 1 mm. 5 ooid grainstone with cross-section of coptocampylodon? rhaeticus n.sp. with irregular inner surface, holotype. locality: kehlstein, thin-section ber 101–4a, scale bar = 0.5 mm. 6, 7 grainstone with cross-sections of coptocampylodon? rhaeticus n.sp. locality: kehlstein, thin-section ber 101–12, scale bar = 0.5 mm. 116 geologia croatica 55/2 117schlagintweit, missoni & gawlick plate 1 118 geologia croatica 55/2 119 plate 2 coptocampylodon? rhaeticus n.sp. from the upper triassic dachstein limestone of the northern calcareous alps 1–2 cross-section. locality: kehlstein, thin-section ber 101–1a, scale bars = 0.2 mm. 3 cross-section. locality: kehlstein, thin-section ber 101–1a–1, scale bar = 0.2 mm. 4, 6 cross-section. locality: kehlstein, thin-section ber 101–12, scale bar = 0.2 mm. 5 cross-section. locality: lofer kalvarienberg, thin-section ks 79 a, scale bar = 0.2 mm. 7 longitudinal section with axial hollow. locality: kehlstein, thin-section ber 101–4b, scale bar = 0.2 mm. 8 longitudinal oblique section. locality: lofer kalvarienberg, thin-section ks 79 a, scale bar = 0.2 mm. 9 fragment possibly showing the transition between the smooth cylindrical part and the furrowed part. locality: kehlstein, thin-section ber 101–1a, scale bar = 0.2 mm. 10 variously oriented sections. locality: kehlstein, thin-section ber 101–12, scale bar = 0.5 mm. 11 longitudinal section of broken fragment. locality: kehlstein, thin-section ber 101–4a, scale bar = 0.2 mm. 12 longitudinal section with central hollow. locality: kehlstein, thin-section ber 101–12, scale bar = 0.5 mm. 118 geologia croatica 55/2 119schlagintweit, missoni & gawlick plate 2 120 geologia croatica 55/2 hydrogeological relationships of the golubinka karst spring in ljubač bay, dalmatia, croatia ante pavičić�, josip terzić� and nicoletta berović2 1. introduction all the water-supply pumping sites of the region of zadar in croatia are situated in a complex coastal catchment area (fig. 1), mostly composed of karstified carbonate rocks. the research area is entirely situated in the adriatic regional structural unit, which is the first southern unit in the dinarides, at the contact between the adriatic microplate to the sw and the dinaric regional structural unit to the ne; contacts between these structural units are represented by reverse faults (kuk et al., 2000; prelogović et al., 2003). all structures in the studied area strike northeast–south geologia croatica 59/2 125–137 8 figs. 5 tabs. zagreb 2006 key words: coastal spring, karst hydrogeology, multivariate analysis, water quality, monitoring, ljubač bay, northern dalmatia, croatia. 1 croatian geological survey, sachsova 2, hr-10000 zagreb, croatia; e-mail: apavicic@hgi-cgs.hr 2 vodovod ltd., water supply co., špire brusine 17, hr-23000 zadar, croatia; e-mail: nicoletta.berovic@zd.htnet.hr abstract the golubinka spring is a typical karst spring situated in northern dalmatia, croatia. the catchment area is mostly composed of limestones of the cretaceous and palaeogene, with some dolomitic parts. hydrogeological barriers are composed of flysch or quaternary sediments, and most of them are “hanging” barriers, so that the karst water can flow underneath. many spelaeological features in the vicinity of the spring point to a typical karst conduit flowing under ground. this has been proven by tracer tests, because a connection exists to the periphery of the catchment with an apparent velocity of 8.1 cm/s. the whole area is situated in the mediterranean climatic belt, so the precipitation distribution is quite unfavourable – summers are long, hot and dry. this is why the summer seasons usually end with sea water intrusion into the aquifer with a significant increase in chloride ion concentration. since the spring is capped for water supply, there is a bulk monitoring system established. the data obtained were processed by means of multivariate analysis, and three main types of quality deterioration were recognized. the first is connected with pollution from agriculture and inhabited areas without sewage, the second represents occasional sea water intrusions, while the third relates to heavy rainfall events accompanied by turbidity and pollution. together with the other conclusions, these results should have a practical purpose primarily in the matter of water protection. west. the terrain is mostly composed of limestone of eocene and cretaceous ages (majcen & korolija, 1973; vlahović et al., 2005). the rock mass is tectonically fractured and karstified. morphologically, the whole catchment area is characterized by small hills and karst fields. the highest peak is only 120 m a.s.l. the only surface water flow in the zadar hinterland, called miljašić jaruga, is situated south of the golubinka spring catchment. climatically, this area belongs to the mediterranean climate, the so-called “olive climate” (šegota & filipčić, 1996). it is known for its dry, hot summers, with most of the precipitation concentrated in the cold part of the year. this rainfall concentration is quite unfavourable considering the lack of water during the summer time, when it is vital for the water supply of the population, tourism and agriculture. average air temperature in january is between 5 and 6°c, and in july about 24°c. 2. geological setting most of the golubinka spring’s catchment area is composed of upper cretaceous dolomites and limestones, palaeogene limestones and clastic rocks (eocene flysch), as well as some quaternary deposits (clays, sandy clays and ‘terra rossa’). upper cretaceous dolomites form the cores of anticlines and occur as outcrops only in the bokanjačko blato structure. dolomites are overlain by well-bedded limestones. upper cretaceous limestones and dolomites are over 400 m thick. palaeogene rocks are transgressive over upper cretaceous deposits. their base is composed of breccias, and conglomerates only occur occasionally. eocene foraminiferal limestones are well bedded, with an increase in bed thickness from the older to the younger parts, on average from 1 cm to almost 1 m. their total thickness is about 300 m. clastic palaeogene rocks – the eocene flysch – is composed of siltites, sandstones and sandy limestones. sandstones are most common in the younger parts. these rocks form the cores of synclines and are usually eroded. the thickness of the flysch rocks in the syncline ne of poličnik is almost 850 m (majcen & korolija, 1973). in the terrain considered here, there are two principal types of quaternary deposits: residual soils in the area near the boljkovac spring, and the terra rossa covering karstified 126 geologia croatica 59/2 limestones. the residual soils originate from weathered flysch and have a significant hydrogeological function because of their thickness (over 20 m – fritz & pavičić, 1991). they act as total or hanging barriers for the karst groundwater. terra rossa (a ‘modal fersiallitic red soil’ situated on limestones) is a polygenetic type of soil which is widespread in the whole mediterranean (miko et al., 1999; durn, 2003). in the golubinka catchment it is quite thin and discontinuous and with no hydrogeological relevance regarding groundwater flow. however, its influence on the hydrochemical properties and even infiltration should not be neglected. from the structural-geological point of view the terrain is composed of several anticlines and synclines. these follow the so-called ‘dinaric’ strike (nw–se), parallel to the coast and most of the topographic water divides. some of the folds are significantly tectonically disturbed, mostly by reverse faults and thrusts. most of them are not visible at outcrops and cannot be traced even morphologically. they have been discovered by a number of boreholes (57) drilled during investigations completed for the purpose of construction of the injection curtain in the late 1960’s (fritz, 19763). maximal displacements amount to 100 m, and the average is between 10–40 m. 3. specific karst features there are two basic facts indicating typical karst flow conditions in the golubinka spring catchment: – very high groundwater velocity, even from far inland, proven by the tracer test; – visible channels and caves at the spring location of the golubinka and nearby springs (pod gredom and šušnjarka). presence of deep vertical caves (pits) in the near hinterland. close to the golubinka spring, there are two other springs called pod gredom to the east, and šušnjarka to the west. there are also three caves: two of them called šušnjarka and one called golubinka, as well as springs closely adjoining them. all the springs have been investigated by scuba divers, but only for a few tens of metres, close to the entrances (fig. 2, and božičević, 19754). because of the strong water current and/or muddy water (turbidity), the divers were not able to progress very far. investigations were stopped and, unfortunately, never continued. the golubinka cave is formed in the eocene foraminiferal limestones about 400 m from the golubinka spring and water supply plant (fig. 3, detail). the cave has been spelaeologically investigated, including spelaeological diving research below groundwater level. the pit’s entrance is situated 39 m a.s.l. the groundwater level in the cave has been measured approximately and comes to less than 1 m a.s.l. at the bottom of the cave there are three mutually connected water basins. the diving exploration revealed some 22 m of water depth. the two šušnjarka vertical caves situated west of the golubinka spring are also formed in eocene limestones. they are only 9 m deep. the distance between them is 14 m, and they are connected below ground. at the bottom there is water of unknown depth. east of the golubinka spring there are two karst springs pod gredom, most probably connected with the other karst features (šušnjarka, the golubinka spring, the golubinka pit, etc.) with underground conduits. the main outflow site of golubinka is now canalized with a channel 1.5 to 3 m wide. the water level in the channel varies from 1 to 2 m. the first pod gredom spring is situated under a cliff, and there are three karst channels from which the groundwater springs. close under ground these three channels connect in one karst conduit, about 80 m from the coast. diving could be performed only up to 27 m in the karst channels from fig. 1 situation map of the investigated area. study area 3 fritz, f. (1976): ravni kotari–bukovica, hidrogeološka studija [ravni kotari–bukovica, hydrogeological study – in croatian].– unpublished report, archive of the croatian geological survey, zagreb, 134 p. 4 božičević, s. (1975): izvorište golubinka – ljubački zaljev, speleološko istraživanje [the golubinka spring – spelaeo-scuba diving investigations – in croatian].– unpublished report, archive of the croatian geological survey, zagreb, 7 p. 127pavičić, terzić & berović: hydrogeological relationships of the golubinka karst spring... the cave entrance. the second pod gredom spring is similar to the first, but here there are two channels connecting in one main karst conduit about 50 m from the cave mouth (the entrance). these diving investigations were never performed as was desired, mainly because of the high turbidity caused by fine-grained material. it was presumed that the channels (after a few tens of metres) continue deeper below ground, and that they are mutually connected as one karst hydrogeological system. 4. hydrogeological relationships the hydrogeological relationships are mostly a consequence of the geological circumstances. the mean elevation of the terrain (relief) is low, close to the recent base of erosion – sea level. it is significant that sea level is now about 100 m higher than that during the last glaciations (würm; šegota, 1982; benac & juračić, 1998; masse & montaggioni, 2001). in the last 6000 years sea level has stabilized (benac fig. 2 spelaeological scheme of the golubinka and pod gredom coastal karst springs entrances (cave mouths) (after božičević, 19754). 128 geologia croatica 59/2 et al., 2004; pirazzoli, 2005). still, the large sea level rise in the holocene caused much deeper karstification than would be expected with the recent sea level. limestones are considered permeable, dolomitic rocks decrease permeability; so if they prevail in some sections, carbonate rocks behave in a less permeable manner. flysch represents impermeable rocks, sometimes acting as a hydrogeological barrier. occasionally, the flysch is not thick enough to stop the flow of groundwater completely. in these cases the groundwater can flow through deep karst conduits under impermeable flysch, and the flysch in those situations behaves as a “hanging barrier”. the catchment area of the golubinka spring (fig. 3) is the northern part of a wider karst catchment called the “bokanjac–poličnik”. this wider catchment covers the whole of the zadar hinterland in nw dalmatia, and most of the well-known karst springs and pit wells are situated within that area. some of these water sources are exploited for water supply. the local catchment of the golubinka spring could be separated from the rest of the terrain by a zonal underground water divide. the flysch rocks in ljubački bay represent an undersea barrier, so the karstified carbonate rocks are in contact with the sea water in quite a narrow area close to the coastline. this circumstance is positive from the hydrogeological point of view, because the groundwater flow from the aquifer can suppress the intruding sea water; thus the golubinka spring water stays fresh until the end of the summer dry periods when the groundwater level in the aquifer drops, together with the discharge, and sea water intrudes. effective infiltration in the whole catchment area formed by carbonate rocks is very high. precipitation falling on the impermeable flysch rocks usually forms short temporary surface streams, which often end in ponors, a specific karst phenomenon. the greater part of the rainfall onto impermeable parts of the terrain is also infiltrated into the karst aquifer through ponors. this primarily applies to the catchment periphery, where the well-known ponor in biljane donje is located. an underground connection between the ponor in biljane donje and the golubinka spring has been proven by a tracer test, and it has a very high groundwater velocity of 8.1 cm/s (fritz, 19763). over the whole area, the greater part of the groundwater typically flows parallel to geological structures, towards the nw. southwest of the golubinka spring, residual soils, over 5 m thick, act as a groundwater barrier (fritz & pavičić, 1991). this barrier is partly “hanging”, so some of the groundwater probably flows underneath it, towards the boljkovac spring. groundwater levels in distant parts of fig. 3 schematic hydrogeological map of the golubinka spring catchment area. 129pavičić, terzić & berović: hydrogeological relationships of the golubinka karst spring... the catchment area (from the coast) are about or above 60 m a.s.l., as is demonstrated by the oko spring (60 m a.s.l.). such elevation causes a significant groundwater gradient and high velocities towards the springs of golubinka or boljkovac. part of the groundwater from this part of the catchment flows through deep karst sumps (siphons) and conduits under the flysch barriers to the bokanjačko polje area. these phenomena have been demonstrated by a few tracer tests from boreholes and the ponor in biljane donje (fritz, 19763) (fig. 3). mean velocities parallel to the geological structures were 1.4, 1.4, 1.0, 3.3, and 8.1 cm/s (average 3 cm/s). mean velocities at right angles and diagonal to the geological structures were 1.4, 2.2, 2.9, 2.3 and 5.0 cm/s (average 2.8 cm/s). high velocities diagonal to the structure are caused by faults. shallow zones are highly karstified, and in deeper zones there is a rock mass of lower permeability, but with a network of karst conduits. that is why sometimes the groundwater velocities were higher to distant boreholes than to ones closer to where the tracer fluid was poured in. these kinds of karst conduits were probably developed during the last 15,000 years when the sea levels were about 70 m lower than today (benac & juračić, 1998). the placement of the water divide which separates the golubinka spring catchment from other catchments in the hydrogeological system is only known approximately, based on knowledge of some minor geological units and features in the area. since it is a zonal divide, it can move significantly according to hydrological conditions. the spring itself is developed in karst conduits which form cave systems at the place where the groundwater surfaces (fig. 2). this occurs some 15 m from the coast, at an elevation of less than 1 m. such proximity to the sea causes occasional saline intrusions in the karst aquifer near the spring site. during the summer dry periods, the groundwater level in the karst aquifer decreases, the golubinka spring discharge also decreases, and water becomes slightly brackish (table 2). the intensity of this phenomenon varies from year to year, according to the annual amount of precipitation. the sensitive karst environment reacts very quickly, and soon after the first significant rains, usually in september, the discharge increases, the chloride level drops and the water becomes fresh again. near the golubinka spring there are also some similar karst springs called pod gredom and šušnjarka. they are also spelaeological formations but their discharge is lower. access is very difficult and this is the main reason why the golubinka was capped for water supply in 1993. the golubinka water supply facility was very important during the war for croatian independence, when most of the other water supply sources were occupied until the liberation in 1995. during that time the facility at the golubinka spring was renovated, and a small dam construction was built at the site where the water springs from the cave. this construction achieved some positive results regarding water quality. by increasing the groundwater levels in the nearby karst underground, saline intrusions in the dry periods were decreased to some extent. unfortunately, there are no relevant data for a parametric description of that decrease. today, the golubinka pumping site is part of the wider water supply system. it usually uses about 100 l/s. when the concentration of the chloride ion becomes exaggerated, the water from the golubinka spring is mixed with water from other pumping sites. when sea water intrusion becomes excessive at the end of the summer dry periods, pumping has to be stopped. experience indicates that this usually happens when the discharge decreases to some 60 l/s. the unfavorable distribution of rainfall throughout the year in the catchment of the golubinka spring causes large differences in the spring’s discharge from minimum to maximum. the average monthly discharge at the golubinka spring as well as the amount of precipitation at the nearby poličnik measuring site are shown in fig. 4. the data from 1961–1990 are divided into two separate sets, because in 1980–1990 there was a dry period in the research area. average monthly precipitation was 87 mm/m2 in the 1961–1980 period and 74 mm/m2 in the 1980–1990 period. during the same time intervals, average monthly discharge at the golubinka spring was 446 and 358 l/s, respectively. the largest discharge occurs in february, and the average for that month is almost 1 m3/s. the lowest discharge is in july (average lower than 100 l/s; žugaj, 1995). for the complete time period the average yearly precipitation was 992 mm/m2 and the average discharge of the golubinka spring was about 417 l/s. 5. hydrogeochemical data 5.1. hydrogeochemical facies, basic relations and seawater intrusion for determination of the hydrogeochemical facies the data from june 2004 (table 1, fig. 5) were used for the golubinka spring, as well as the oko and boljkovac springs (fig. 3). although samples were taken in june 2004, there were no high chloride concentrations, and water at the two sites was of the ca–hco3 type. however, the sample at the boljkovac spring (well) showed the na–cl type, which means that this spring was already subject to sea water intrusion (fritz & pavičić, 1991). this is most probably a consequence of the extensive pumping for water supply that was being done during the period when sampling took place. water extraction lowered the water level and gradient so that sea water intruded from the western side, or from the lower levels (“upwelling” of the sea water). this situation also indicates that it is justifiable to locate the groundwater divide between the golubinka and boljkovac springs – these are most probably two quite distinct groundwater systems. in contrast, samples at the oko and golu130 geologia croatica 59/2 binka show very similar ionic composition. the spatial position of the oko spring, half way between the ponor in biljane donje and the golubinka spring, implies that this water probably belongs to the same karst aquifer. in the climatic belt under discussion the dry season begins in june, and the karstified underground aquifer begins to discharge water accumulated during the rainy half of the year. the result of that discharge is the lowering of the groundwater table, so the springs in coastal zones, such as golubinka, could suffer intrusion by sea water. the main indicator (and result) of such mixing of salt and fresh water is a higher concentration of chlorides, as shown by levels up to 1630 mg/l in september 2003 (table 2) in the research period. it can be seen that during the late part of every summer season there is an increase in the chloride concentration (fig. 6). the amount of that increase varies from year to year, depending on the hydrological conditions. 5.2. quality monitoring: data acquisition the zadar water supply company has established permanent monitoring of the water quality at the golubinka spring. data for the period 2003–2006 (table 2) have been statistically analyzed, by means of correlation and multivariate factor analysis. in the basic analysis for the purpose of monitoring the water quality, 20 parameters are periodically measured. besides the 14 analyzed parameters (table 2), others noted include smell, taste, oxidativity, free residual chlorine, free ammonia and nitrite concentration. the measurement of these parameters is within the socalled “basic analysis” and it is determined by current legislation in croatia (narodne novine, 2004). the 6 parameters that are not analyzed either (1) were not measured, (2) are just descriptive, or (3) relate to treated water. the 14 parameters (table 2) are suitable and sufficient for a basic estimation of water quality. the main goal of further statistical and mathematical analysis was to describe the relationships between some of the parameters, and to group parameters into factors fig. 4 average monthly discharge of the golubinka karst spring and average monthly precipitation at the poličnik measuring site (žugaj, 1995). cnd t ph hco3 na k ca mg so4 cl no3 (μs/cm) (°c) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) golubinka 781 14.8 7 271 17.9 1.8 80 7.5 14.9 33 7.4 oko 786 14.5 6.92 280 18.5 1.3 85 5.2 15 33.8 7.5 boljkovac 4170 14.6 6.91 281 628 22 104 69 230 1050 8.5 table 1 basic ion composition for samples at the golubinka, oko and boljkovac springs, june 2004. 131pavičić, terzić & berović: hydrogeological relationships of the golubinka karst spring... which can be attributed to natural processes (basically, describing the origin of possible pollution). 5.3. mathematical and statistical analysis of results 5.3.1. statistical correlation there are only a few statistical correlations (regressions) that are really worth considering. the most important relationship is between chlorides and electrolytic conductivity (fig. 7). it is important to point out that this is a correlation matrix (table 3) without colour measurements. measurement of colour began at the end of 2005, so it was better not to calculate it together with the other parameters in such a matrix. nevertheless, there is an interesting connection between colour and turbidity (r=0.98). those two relationships could be shown by linear equations (1) and (2): [cl] = 0.31*ec-200.6 (1) tb = 0.6*co+0.18 (2) where: [cl] – chloride concentration (mg/l); ec – electrolytic conductivity (μs/cm); tb – turbidity (ntu units), and co – colour (mg/l pt/co scale). there are also connections between the other parameters, but not as high as these two. 5.3.2. r mode multivariate factor analysis more interesting data were achieved by means of the multivariate exploratory technique – factor analysis (table 4, fig. 8). in this calculation some parameters were grouped in the factors, and colour was also put into the calculation. the main purpose of such analysis is to express variables as groups of variables (factors). in this manner the number of variables is reduced, and groups of variables (calculated factors) in a “factor space” could be presented as processes in a real environment. the data structure that is hidden from direct observation or measurement is recognized (davis, 1986; peh, 1992, 1994). such analysis is often used in similar studies, especially for estimating the source of pollution (ahmed et al., 2005; singh et al., 2005; shrestha & kazama, 2007). the data (table 2) were subjected to multivariate factor analysis and five factors were extracted (table 4). processing was done by the statistica software, using the extraction by principal components and ‘varimax’ rotation. only factors with eigen values above 1.0 are emphasized. the eigenvalue of the 1st factor is 26% of the total variance, for the 2nd factor it is 16%, and for the 3rd 12%. the interpretation of the 4th and 5th factors is much lower and they can hardly be attributed to natural processes, since they are described with low eigenvalues and only one or two (which are actually one) variables. when a facfig. 5 basic ionic composition presented by piper diagram. 132 geologia croatica 59/2 28.02.2003. 1.4 13 6.9 890 44 5.72 0 0 2 0 60 30 0 10.04.2003. 1.1 14 6.8 1011 105 8.36 240 240 0 0 64 280 0 21.05.2003. 1.7 20 6.7 1360 260 7.92 15 5 0 0 42 24 0 30.05.2003. 1.35 19 6.8 1670 323 8.36 15 2 0 0 20 60 0 27.08.2003. 1.1 18 7.1 4040 1030 9.24 5 5 0 0 120 30 0 04.09.2003. 1.3 18 7 5530 1630 6.95 5 2 0 0 10 20 0 10.10.2003. 3.5 18 7 4115 1029 3.52 96 2 0 0 20 10 0 22.10.2003. 4.5 16.5 7 5400 1477 8.36 240 240 16 0 52 26 0 03.11.2003. 0.8 7.1 3130 775 7.92 240 240 0 0 410 150 0 10.11.2003. 0.98 16.5 7 2700 740 9.24 240 240 38 0 320 210 0 21.11.2003. 2.7 15 6.9 3330 795 15.84 240 240 9 1 100 90 0 26.02.2004. 3.1 7 760 36 9.68 240 240 15 1 5950 3500 0 04.03.2004. 3 13.5 7 790 92 8.36 38 2 5 1 440 60 0 15.04.2004. 11.5 15 7.3 700 32 8.668 240 240 38 0 2050 560 0 02.06.2004. 1 19 7.2 770 40 9.94 38 38 2 0 56 4 0 16.06.2004. 1.5 17 6.8 930 81 10.60 240 4 16 2 64 32 0 09.07.2004. 1.2 24.5 6.9 1420 255 9.55 12 0 2 0 41 24 0 30.07.2004. 1.7 22 6.9 2030 462 8.32 240 8 5 0 122 50 0 17.08.2004. 1 15.5 7 3140 604 8.67 240 9 0 0 212 80 0 01.09.2004. 1.7 7 2990 780 8.8 15 0 0 0 29 20 0 14.09.2004. 0.9 16.5 6.8 2690 600 8.40 9 2 0 0 28 30 0 01.10.2004. 0.8 6.9 3040 746 7.48 38 9 2 0 114 83 0 20.10.2004. 1.5 15 6.6 2760 640 8.27 15 15 0 0 36 32 0 15.12.2004. 2.4 14 6.8 740 34 10.56 27 9 9 0 770 164 0 16.02.2005. 1.34 15 6.9 765 31 8.8 9 9 0 0 27 160 0 07.04.2005. 3.4 16 6.7 780 45 8.36 240 240 2 0 326 42 0 06.05.2005. 1.5 17 6.7 762 40 7.92 38 38 16 2 678 310 0 19.07.2005. 1.4 20 6.9 1850 362 8.67 38 38 0 0 68 58 0 12.08.2005. 0.4 18 7 2240 485 8.36 96 15 2 0 246 6500 0 06.09.2005. 1.8 20.5 6.9 2120 447 8.89 240 240 16 0 68 10 0 14.09.2005. 0.6 16 7 2300 505 9.77 240 240 16 2 1300 62 0 06.10.2005. 0.9 15 6.9 1580 250 10.12 38 38 1 0 131 62 0 17.10.2005. 1.2 6.9 3530 850 14.26 240 240 16 2 3140 820 2 11.11.2005. 3 1.6 15 6.8 720 27 10.03 240 240 16 0 193 86 0 29.11.2005. 10 5.5 14 7.1 690 25 9.37 240 240 2 0 990 540 0 07.12.2005. 30 20.6 14 6.8 785 46 10.12 240 240 16 0 6500 120 0 09.12.2005. 30 16.7 6.7 820 50 7.92 240 240 216 2 133 78 0 12.12.2005. 8 5.4 13.5 7.5 830 53 7.39 38 38 16 0 253 84 0 13.01.2006. 3 1.9 13.5 6.9 780 40 8.8 240 240 9 2 79 53 0 03.02.2006. 0 0.63 13.5 7 3360 765 8.54 5 5 0 0 60 120 0 03.03.2006. 3 2.4 13.3 6.9 760 37 7.39 15 9 2 0 3600 4500 0 10.03.2006. 3 1.92 13 6.9 765 35 7.44 17.03.2006. 3 2.8 14 6.9 760 35 7.26 38 38 9 0 110 440 0 07.04.2006. 3 2.1 14.5 6.8 820 35 8.67 38 38 2 0 77 46 0 12.04.2006. 3 1.6 15 6.9 740 30 7.79 15 15 3 0 1 25 0 21.04.2006. 3 1.9 14.5 6.8 750 34 8.8 05.05.2006. 10 4.1 15.5 6.8 775 39 6.6 240 240 16 1 1200 1700 0 15.05.2006. 5 2.8 17 6.8 760 35 8.36 240 240 0 2 3620 960 0 19.05.2006. 3 1.9 15.5 6.8 760 36 8.01 38 9 2 0 210 110 2 02.06.2006. 0 1.4 16.5 6.8 780 34 6.38 38 5 2 0 400 280 8 c ol ou r (m g/ l p t/c o sc al e) tu rb id ity (n tu u ni ts ) te m pe ra tu re (° c ) ph ec (μ s/ cm ) c l (m g/ l) n o 3 (m g/ l) t. c ol ifo rm s (n o/ 10 0m l) f. c ol ifo rm s (n o/ 10 0m l) f. s tr ep to co cc i (n o/ 10 0m l) c lo st rid iu m p er f. (n o/ 10 0m l) a er ob ic b ac te ria 22 °c (n o/ 10 0m l) a er ob ic b ac te ria 37 °c (n o/ 10 0m l) ps eu do m on as a er . (n o/ 10 0m l) table 2 hydrochemical, physical and microbiological parameters from 2003 to 2006. 133pavičić, terzić & berović: hydrogeological relationships of the golubinka karst spring... tor is expressed only with one variable, it can be taken as a boundary (the eigenvalue can be ignored), and no further extraction is needed. factors 4 and 5 are less important because they are connected with only one or two parameters, so the interpretation is limited. their eigenvalues are smaller, as well as their interpretative connection with the natural systems. although the calculation shown indicates three main types of water quality deterioration, this does not mean that these are the only polluting processes in the system. they are merely the processes that could be recognized by the parameters monitored, and the purpose of monitoring is connected with pollution. if there were more parameters continually measured, there would possibly be more important processes recognized in the system. for example, dissolution of carbonates would probably be recognized, and calcium and carbonate ion in that potential factor would be loaded. this presumption is justified because the golubinka spring water is of the ca–hco3 facies (table 1, fig. 5). the three most important factors which could indicate natural processes are: fig. 6 chlorides and nitrates concentration during the investigation time. fig. 7 correlation between chlorides and electrolytic conductivity at the golubinka spring. 134 geologia croatica 59/2 turbidity 1 -0.25 0.16 -0.18 -0.17 0.07 0.32 0.39 0.4 -0.08 0.76 -0.04 -0.07 temp. 1 -0.08 0.26 0.28 -0.01 -0.05 -0.19 -0.12 -0.09 -0.24 -0.05 0 ph 1 0.16 0.16 -0.02 0.03 0.03 0.29 -0.16 -0.04 0.05 -0.13 ec 1 0.99 -0.02 0 -0.07 -0.09 -0.17 -0.27 -0.08 -0.14 cl 1 -0.03 -0.01 -0.06 -0.05 -0.17 -0.26 -0.08 -0.14 no3 1 0.3� 0.32 0.19 0.21 0.07 -0.12 -0.21 total coliforms 1 0.83 0.5� 0.35 0.28 -0.03 -0.14 faecal coliforms 1 0.54 0.28 0.35 -0.06 -0.15 f. streptococci 1 0.21 0.23 -0.05 -0.1 clostridium 1 0.16 -0.03 -0.09 aer. bacteria 22°c 1 0.26 -0.04 aer. bacteria 37°c 1 -0.03 pseudomonas 1 tu rb id ity te m p. ph ec c l n o 3 to ta l c ol ifo rm s fa ec al c ol ifo rm s fa ec al s tr ep to co cc i c lo st rid iu m a er ob ic b ac te ria 2 2° c a er ob ic b ac te ria 3 7° c ps eu do m on as table 3 correlation between monitored parameters. high correlation coefficient is shown by gray shading, medium correlation only by bold font. factor eigenvalue % total cumulative cumulative variance eigenvalue % � 3.69 26.36 3.69 26.36 2 2.19 15.66 5.88 42.02 3 1.63 11.66 7.51 53.68 4 1.37 9.79 8.88 63.46 5 1.06 7.60 9.95 71.06 table 4 eigenvalues and variance percentages for extracted factors. fig. 8 multivariate factor analysis diagram. factor loadings: factor 1 vs. factor 2. 135pavičić, terzić & berović: hydrogeological relationships of the golubinka karst spring... – factor 1 – nitrates and some biological components indicate pollution caused by agriculture and inhabited places without sewage infrastructure; – factor 2 – chlorides, electrical conductivity and temperature grouped together represent a mixing with sea water either underground (intrusion) or as a consequence of sea water spray scattered on land by wind and infiltrated into the aquifer by precipitation; – factor 3 – also pollution, but this time connected with turbidity and colour – this usually occurs after heavy rains. 6. discussion and conclusions the golubinka spring is situated in a rock mass composed of eocene limestones. these rocks are highly karstified, so that the spring occurs in a cave. in the vicinity of the golubinka spring, there are more springs, also connected with some vertical caves in the close hinterland (figs. 2 and 3). high tracer velocities from distant parts of the catchment area indicated karstification in the whole aquifer. the majority of those karst conduits are sumps in the deep underground, usually below the present sea level. such a karst conduit network could originate from the period before sea level stabilization (6000 years before present – pirazzoli, 2005), when the mean sea level was about 100 m (25,000 years bp – šegota, 1982) or 70 m (15,000 years bp – benac & juračić, 1998) lower than today. outside these preferential flow directions, there is a fractured rock mass that could be regarded as a continuous medium. it is very important that in such karst environments a high ratio of the precipitation infiltrates very quickly. the golubinka spring behaves like a typical karst spring, with a significant difference in its minimum and maximum discharges, as well as a rapid response to precipitation (fig. 4). hydrogeological circumstances are additionally complicated by the fact that this is a coastal spring subjected to sea-water intrusions during the dry summer seasons. since this spring is capped for water supply, continuous monitoring of the water quality had to be carried out (table 2). when the saline intrusion exceeds the permissible amount, pumping of the water has to be stopped, or the golubinka water is mixed with water from other pumping sites. the position of the oko spring, half way between the ponor in biljane donje and the golubinka spring, indicates that they belong to the same karst aquifer. this is an important conclusion because the oko spring is about 60 m a.s.l, equating to a hydraulic gradient of approximately 0.006. the problems with the water supply from these two springs are different. at the end of the summer dry season, the oko spring significantly lowers its capacity (below the economically justified quantities), while the golubinka water supply station lowers its extraction capacity as a result of the sea water intrusion. parts of the golubinka spring catchment are affected by extensive agricultural production, but this does not greatly influence water quality, as shown by the level of nitrates, which is always below 16 mg/l (fig. 6). under croatian legislation, the permitted quantity of nitrates is a maximum of 50 mg/l. even so, agricultural production near the ponor in biljane donje could cause pollution because of the high groundwater velocity, and quite limited purification capacity of the karst underground. consequently that ponor must be monitored and put under sanitary protection, however far it is from the spring. besides, some other minor ponor zones in the catchment, together with tectonically preferred flow directions in the vicinity of the golubinka spring, should also be monitored and protected. there is extensive agricultural production, as well as inhabited places without sewage systems, but despite this the water in the golubinka spring is able to satisfy regulatory criteria for potable water quality. determined factors that could cause pollution should be monitored, and sustainable water protection zones ought to be established as soon as possible. if this could be done, there is a good chance of protecting and keeping this important karst groundwater for use as potable water in the future. with regard to the amount of nitrates, it is also important to point out that their amount in the groundwater is not susceptible to classification. that is because the concentration of nitrates depends on many factors, such as the composition of the soil through which water drains, forests, waste materials, agriculture, etc. (canter, 1997). also, below the surface there is no light, restricting the use of all nutrient substances for life support and primary production in the groundwater. all nitrogen compounds (nitrogen gas, ammonium, nitrites, etc.) transform to nitrates (canter, 1997). as is recognized by the factor analysis, the three most important sources of pollution are settlements without sewage systems, seawater intrusion and ‘washing out’ from soil and the shallow epikarst belt by heavy rainfall events. grouping of variables in factors (table 5) would not be recognized by statistical regression, but factor analysis recognized it quite clearly, so the interpretation of factor space by natural processes was not difficult. in further monitoring, considering measured variables as parts of factors could increase the level of interpretation concerning pollution sources, even if other variables do not act accordingly in the beginning. for example, increase in colour and turbidity would point to the physical pollution of heavy rainfall (which is quite obvious) but, most importantly, to a possible occurrence of faecal streptococci in the water. with constant quality monitoring and implementation of sanitary protection, even a karst coastal spring such as this could be included in the water supply system. although this is a typical and very sensitive karst environment, all of the parameters that indicate pollution are below the permitted limits. all the new information about the behavior of the golubinka karst spring 136 geologia croatica 59/2 should improve water quality and ensure large quantities of potable water for use in the future. 7. references ahmed, s.m., hussain, m. & abderrahman, w. (2005): using multivariate factor analysis to assess surface/logged water quality and source of contamination at a large irrigation project at al-fadhli, eastern province, saudi arabia.– bull. eng. geol. environ., 64, 319–327. benac, č. & juračić, m. (1998): geomorphological indicators of sea level changes during upper pleistocene (würm) and holocene in the kvarner region (ne adriatic sea).– acta geographica croatica, 33, 27–45. benac, č., juračić, m. & bakran-petricioli, t. (2004): submerged tidal notches in the rijeka bay ne adriatic sea: indicators of relative sea-level change and of recent tectonic movements.– marine geology, 212, 21–33. canter, l.w. (1997): nitrates in groundwater.– lewis publishers, crc press, new york, london, tokyo, boca raton, 263 p. davis, j.c. (1986): statistics and data analysis in geology.– john wiley & sons, new york, 646 p. durn, g. (2003): terra rossa in the mediterranean region: parent materials, composition and origin.– geologia croatica, 56/1, 83–100. fritz, f. & pavičić, a. (1991): the boljkovac spring, croatia – a case of the overexploitation of a karst spring.– xxiii i.a.h. congress “aquifer overexploitation”, proceedings, canary islands, spain, 515–518. kuk, v., prelogović, e. & dragičević, i. (2000): seismotectonically active zones in the dinarides.– geol. croatica, 53/2, 295–303. majcen, ž. & korolija, b. (1973): osnovna geološka karta sfrj 1:100.000, list zadar l33–139 (basic geological map of the sfry, scale 1:100.000, zadar sheet).– institut za geološka istraživanja zagreb (1963–1969), savezni geološki zavod, beograd. masse, j.p. & montaggioni, l.f. (2001): growth history of shallow-water carbonates: control of accommodation on ecological and depositional processes.– int. j. earth sciences (geol. rundschau), 90, 452–469. miko, s., durn, g. & prohić, e. (1999): evaluation of terra rossa geochemical baselines from croatian karst regions.– journal of geochemical exploration, 66, 173– 182. narodne novine (2004): pravilnik o zdravstvenoj ispravnosti vode za piće [directions on the health propriety for potable water – in croatian].– narodne novine – official bulletin of the republic of croatia, 182, 14 p. peh, z. (1992): factor model of the geomorphological system of a part of northwestern croatia.– geol. croatica, 45, 163–172. peh, z. (1994): faktorski model kao izraz dinamike geoloških procesa na primjeru sjeverozapadnog dijela hrvatskog zagorja [the factor model as the expression of dynamics of geological processes in the northwestern croatia – in croatian with english abstract].– unpubl. phd thesis, university of zagreb, faculty of mining, geology and petroleum engineering, 162 p. pirazzoli, p.a. (2005): a review of possible eustatic, isostatic and tectonic contributions in eight late-holocene relative sea-level histories from the mediterranean area.– quaternary science reviews, 24, 1989–2001. prelogović, e., pribičević, b., ivković, ž., dragičević, i., buljan, r. & tomljenović, b. (2003): recent structural fabric of the dinarides and tectonically active zones important for petroleum–geological exploration in croatia.– nafta, 55/4, 155–161, zagreb. shrestha, s. & kazama, f. (2007): assessment of surface water quality using multivariate statistical techniques: a case study of the fuji river basin, japan.– environmental modeling and software, 22, 464–475. factor 1 factor 2 factor 3 factor 4 factor 5 colour (mg/l pt/co scale) 0.11 -0.06 0.93 0.08 0.03 turbidity (ntu units) 0.09 0.20 0.89 0.15 0.18 temperature (°c) -0.12 -0.60 0.04 0.01 -0.41 ph -0.07 -0.10 -0.12 0.11 0.77 ec (μs/cm) 0.03 -0.92 -0.10 -0.11 0.24 cl (mg/l) 0.02 -0.92 -0.09 -0.10 0.23 no3 (mg/l) 0.68 -0.08 -0.11 0.00 -0.02 total coliforms (no/100 ml) 0.82 0.00 0.26 0.10 0.13 faecal coliforms (no/100 ml) 0.8� 0.09 0.28 0.11 0.21 faecal streptococci (no/100 ml) 0.19 0.06 0.80 -0.15 -0.14 clostridium perfringens (no/100 ml) 0.65 0.11 0.16 0.01 -0.36 aerobic bacteria 22°c (no/100 ml) 0.32 0.19 0.26 0.75 0.07 aerobic bacteria 37°c (no/100 ml) -0.04 0.03 -0.11 0.87 -0.04 pseudomonas aeruginosa (no/100 ml) -0.08 0.09 -0.17 0.08 -0.46 table 5 multivariate factor analysis. factor loadings for the five most important factors. 137pavičić, terzić & berović: hydrogeological relationships of the golubinka karst spring... singh, k.p., malik, a. & sinha, s. (2005): water quality assessment and apportionment of pollution sources of gomti river (india) using multivariate statistical techniques – a case study.– analytica chimica acta, 538, 355–374. šegota, t. (1982): razina mora i vertikalno gibanje dna jadranskog mora od ris–würmskog interglacijala do danas [the sea level and vertical movements of the adriatic sea bottom since ris–würm glaciations till today – in croatian].– geol. vjesnik, 35, 93–109. šegota, t. & filipčić, a. (1996): klimatologija za geografe [climatology for geographers – in croatian].– školska knjiga, zagreb, 471 p. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeography, palaeoclimatology, palaeoecology, 220, 333–360. žugaj, r. (1995): regionalna hidrološka analiza u kršu hrvatske [regional hydrological analysis in croatian karst – in croatian].– croatian hydrological society, zagreb, 139 p. manuscript received september 1, 2006. revised manuscript accepted november 24, 2006. 138 geologia croatica 59/2 geo.cro.2-3-61-kb.pdf 123 � bernard mamet and alain préat ab stra ct until recently cummingsella was only known by two rare and puzzling species, erected on very limited material. the genus was therefore considered as representing a very uncommon and puzzling form that played no role in carbonate sedimentation. recent studies of viséan carbonates in the american midcontinent have disclosed a prolifi c cummingsella fl ora that indicates the proximity of an algal bank. cummingsella can therefore be considered locally abundant and cosmopolitan (europe, australia, north america), ranging in age from the tournaisian to the namurian (serpukhovian). keywor ds: carboniferous, chlorophyta, distribution département des sciences de la terre et de l’environnement, université libre de bruxelles, cp160/02, av. f.-d. roosevelt, 50, b-1050, bruxelles, belgique; (apreat@ulb.ac.be) the hunt for cummingsella (carboniferous, chlorophyta) geologia croatica 61/2–3 123–128 1 fig. 2 pls. zagreb 2008 geologia croaticageologia croatica � 1. previous work hutton (1965) in his ph.d. thesis described namurian foraminifera and algae of the limestone coal group of the upper limestone outcropping in southern scotland. he also restudied some of the collections originally made by r.c. cummings from the same levels (top hosie, index, lyoncross, orchard, calmy). the same year, hutton showed his material to the senior author (bernard mamet) during a visit to glasgow. one thin-section yielded a curious alga that did not fi t previous diagnosis or description. unfortunately there was only one well-oriented section of the thallus. in 1978, dr. i. rolfe of the hunterian museum in glasgow shipped additional material to brussels, but it provided no additional information. the same level of the lyoncross limestone in the original quarry was disappointing as only fragments of the thallus could be detected. it is obviously unwise to erect a new genus on a single good section, but the morphology was so curious that alain roux convinced mamet to overcome his prejudices. we fi nally proposed the new genus cummingsella (cummingsella lyoncrossi; pl. 1, fig. 1) in honour of r.c. cummings, a pioneer of foraminiferal and algal research in the carboniferous of great britain (mamet & roux, 1980). there was some unease as related or similar morphologies had not been recognized in the literature. however, a few years later, we observed another unique cummingsella sp., this time in australia. the dimensions were far more modest but the morphology quite similar to the scottish species and we named the taxon c. bingleburrae (from the late tournaisian, bingleburra formation, new south wal es). needless to say, the species was again erected on one single unique, longitudinal section and no further thinsections brought additional information. fi gu re 1: location of sugar creek. ka – kansas, io – iowa, ill – illinois, mo – missouri. geologia croatica geologia croatica 61/2–3 124 plate 1 1 cummingsella lyoncrossi mamet & roux 1980. reproduction of original holotype, pl.1, fi g. 1, photograph ro.29/6, sample uk209, collection mamet, u. of b. 8253, lyoncross limestone, upper zone 17, namurianserpukhovian, whitecraigs, renfrewshire, scotland, x78. 2 cummingsella bingleburrae mamet & roux 1983. reproduction of the holotype, pl. 4, fi g. 8, sample canberra cpc24047, mamet collection 9f, 526/29, bingleburra formation, uppermost zone 9, tournaisian, bingleburra, new south wales, australia, x121. 3–17 cummingsella bingleburrae mamet & roux 1983. all material from the upper “warsaw” formation, sugar creek quarry, kansas city, kansas, zone 12, viséan, x121. 3, 11, 13, 17 sligthlty oblique sections with micritized and corroded central medulla; fig. 3 – u. of b. 916/35, sample 95/2/863; fig. 11 – u. of b. 914/5, sample 94/2/690; fig. 13 – u. of b. 915/3, sample 94/1/625, fig. 17 – u. of b. 913/30, sample 95/2/863b. 4, 5, 6, 15 longitudinal sections with somewhat corroded medulla. sample 6 broken between two segments. fig. 4 – u. of b. 917/32, sample 94/2/691, fig. 5 – u. of b. 917/3, sample 95/2/873; fig. 6 – u. of b. 917/1, sample 95/2/870; fig. 15 – u. of b. 914/6, sample 94/2/690b. 7–9 axial sections with medulla. fig. 7 – u. of b. 913/31, sample 95/2/863b; fig. 8 – u. of b. 913/35, sample 95/2/864; fig. 9 – u. of b. 917/30, sample 94/2/690c. 10 axial section with dichotomy. u. of b. 915/6, sample 94/1/603. 12, 14, 16 longitudinal sections; segment 16 is broken. fig. 12 – u. of b. 915/8, sample 94/2/693; fig. 14 – u. of b. 916/19, sample 96/2/704, fig. 16 – u. of b. 914/7, sample 94/2/601. geologia croaticabernard mamet and alain préat: the hunt for cummingsella (carboniferous, chlorophyta) 125 geologia croatica geologia croatica 61/2–3 126 plate 2 all samples are from the middle viséan zone 12, “warsaw” formation, sugar creek quarry, kansas city. kansas. 1 well-sorted fossil grainstone. three reworked mud-fi lled cummingsella thalli (lower left, upper right) associated with pitted echinoderms, mud-fi lled broken fenestellid fronds and brachiopod shells. high energy, upper ramp. sample 95/2/870, u. of b. 917/5, x31. 2 medium-sorted fossil grainstone. longitudinal section of cummingsella (centre). pitted echinoderms, numerous brachiopod shells, mud-fi lled gastropod, fenestellids, asphaltina sp. and earlandia sp. high energy, upper ramp. sample 94/1/693, u. of b. 918/30, x31. 3 recrystallized, poorly-sorted fossil packstone. some pressure solution. axial and longitudinal sections of asphaltina cordillerensis mamet in petryk & mamet, 1972. this common and cosmopolitan carboniferous species is characteristic of medium to high energy carbonates. echinoderms and bryozoans. middle part of ramp. sample 96/2/689, u. of b. 916/12, x31. 4 asphaltina cordillerensis mamet in petryk & mamet, 1972 in an echinoderm-bryozoan grainstone. sample 95/2/872, u. of b. 917/9, x78. geologia croaticabernard mamet and alain préat: the hunt for cummingsella (carboniferous, chlorophyta) 127 geologia croatica geologia croatica 61/2–3 128 it has to be admitted that the “erection” of a new taxon on one single section is not to be recommended and is equivalent to “skating on thin ice”. to make things worse, no new material to substantiate this claim was discovered for 25 years. moreover the attribution of the genus to higher levels was unclear but could suggest the dasycladales or the “udoteaceae” (halimedaceans). bucur (1999) attributed the two species to the halimedaceans. but no new discoveries of the genus could be found. thus the recent observations of abundant cummingsella in the viséan of north america, which are the subject of this note, are welcomed. 2. location, stratigraphy and microfacies due to the expansion of the lafarge cement sugar creek quar ry in the vicinity of kansas city, kansas (fig. 1), a number of drill-holes were made to test the quality of the mississippian carbonates. they provided a detailed stratigraphic succession from the viséan (= meramecian) “warsaw” and st. louis for mations. the level that contains numerous cummingsella is located at the top of the “warsaw” formation, just below the contact with the overlying st louis limestone. it can be traced over a square kilometre and is 10–12 metres in thickness. a few hundred thin-sections yielded the following observations. microfacies are composed of high-energy, reworked fossil grainstones and packstones (pl. 2). there is extensive pressuresolution among the packstones. the macrofauna is com posed of pitted echinoderms, brachiopods, mud-fi lled gastropods and fenestellid fronds (pl. 2, figs. 1, 4). foraminifera are plentiful: including primitive “archaediscus” sp., earlandia sp., endothyra sp., eoendothyranopsis sp., eoendothyranopsis hinduensis (skipp, 1969), eoendothyranopsis spiroides (zeller, 1957), eoforschia sp., globoendothyra sp., pseudotaxis sp., skippella sp. and tetraxis sp. reworked algal thalli, calcispheres and microproblematica are represented by: asphaltina cordillerensis mamet in pet ryk & mamet, 1972 (pl. 2, fi gs. 3–4), calcisphaera laevis williamson 1881, calcisphaera pachysphaerica (pronina 1963), cummingsella bingleburrae mamet & roux 1983, girvanella sp. and pseudostacheoides loomisi (petryk & mamet 1972). each thin-section contains from 5 to 20 cummingsella and the total observed fl ora amounts to 400 thalli. the paleoenvironment is within the fair-weather wave base, at the base of the euphotic zone. the age is zone 12, in the upper part of the zone, middle viséan. the age is different from australian material (late tournaisian) but the overall microfacies is quite similar. the abundance of reworked, heavily micritized thalli suggests the proximity of an algal bank. 3. palaeontological description cummingsella bingleburrae mamet & roux 1983 (pl. 1, figs. 2–17) description: small species of cummingsella has diameter of segments around 200–250 µm. the thallus is perforated by a central cylindrical medula (60 to 110 µm). ramifi cations are regular, 10 to 12 at the same level, equidistant, bifurcated as single or double tufts. diameter is 25–30 µm. comparison: the periphery of the thallus is less seg ment ed than the original material. however, the central medulla is often enlarged by micritization and corrosion, and thus appears artifi cially segmented. this indicates extensive diagenesis (the thallus was probably aragonitic) and has caused confusion in the past between the attribution to dasycladales and “udo teaceans”. prof. bucur suggests the possibility of intusannulations, suggesting junctions of lateral fi laments. 4. conclusion the hunt for cummingsella is a good illustration of the fl uctuating state of knowledge of the palaeozoic algae. many gen era, often recognized on insuffi cient data, seem endemic to a region, appear to be scarce, and of dubious sedimentological consequence. they may suddenly appear, and by chance have very different connotations. hence palaeogeographic reconstructions and migration patterns based on microfl ora have to be taken “cum grano salis”. acknowledgement we thank the reviewers prof. i.i. bucur and dr b. chu vashov for their useful suggestions which have improved the manuscript. references bucur, i. i. (1999): stratigraphy signifi cance of some skeletal algae (dasycladales, caulerpales) of the phanerozoic. – in: farinacci, a. & lord, a. (eds.): depositional episodes and bioevents. palaeopelagos spec. publ., 2, 53–104. hutton, a.n. (1965): foraminifera of the upper limestone group of the scottish carboniferous. – unpublished ph.d. thesis, 377 p, glasgow. mamet, b. & roux, a. (1980): cummingsella lyoncrossi n.gen., n.sp., algue nouvelle du namurien d’ecosse. – géobios, 13/5, 787–793. mamet, b. & roux, a. (1983): algues dévono-carbonifères de l’australie. – revue de micropaléontologie, 26/2, 63–130. petryk, a. & mamet, b. (1972): lower carboniferous algal fl ora, southwestern alberta. – canadian journal earth sciences, 9, 767–802. pronina, t.v. (1963): carboniferous foraminifers of the berezovo series in the eastern slope of the southern ural mountains [in russian]. – akademiia nauk sssr, ural branch, geologii institut trudy, 65, 119–176, sverdlovsk. skipp, b. (1969): foraminifera. – in: mckee, e. & gutschick r. (eds.): history of the redwall limestone of northern arizona. geol. soc. am., memoir 114, 173–255. williamson, w.c. (1881): on the organization of the fossil plants of the coal mesaure (part x). including an examination of the supposed radiolarians of the carboniferous rocks. – royal society of london, philosophical transactions, 20, 493–539. zeller, e.j. (1957): mississippian endothyroid foraminifera from the cordilleran geosyncline. –j. paleont., 31, 679–704. manuscript received november 16, 2007 revised manuscript accepted may 19, 2008 01 tesovic-mezga-glumac.indd 3 � 1. introduction di no saur foot prin ts we re dis co ve red re cen tly in up per tit honian stra ta expo sed in an ac ti ve quar ry near kir me njak vil la ge (about 2 km sou th of the sv. lov reč–po reč road) in wes te rn is tria, croa tia (mezga et al., 2003; mezga et al., 2007) (fig. 1). the is trian pe nin su la is in the nor thwes te rn pa rt of the ad ria ti c-di na ri dic car bo na te plat fo rm, (adcp; al so re fered to as ad ria tic car bo na te plat fo rm, see dis cus sion in vlahović et al., 2005). the se di men ta ry suc ces sion main ly con sis ts of shal low wa ter car bo na tes wi th a stra tig rap hic ran ge from the la te mid dle ju ras sic to the eo ce ne (velić et al., 2003), and to a les ser exte nt of eo ce ne clas tic roc ks and qua ter na ry ter ra ros sa and loe ss de po si ts. the kir me njak lo cali ty rep re sen ts the ol de st evi den ce of a di no saur pre sen ce on the adcp to da te, wi th a to tal of 971 do cu men ted foot prin ts. it al so rep re sen ts the lar ge st si te wi th di no saur trac ks dis co vered on the adcp so far (mezga et al., 2007), wi th 23 trac kways, and ot her foot prin ts oc cur ri ng in di vi dual ly or in grou ps. based on their ove ra ll mor pho lo gy, the foot prin ts are at tri buted to sau ro pod di no sau rs. the ob jec ti ve of this stu dy was to use stab le iso to pes of oxygen and car bon in co njun ction wi th pet rog rap hic ob serva tio ns of car bo na te roc ks, to un ra vel de tai ls about the mar ginal ma ri ne or coas tal en vi ron men ts in whi ch lar ge quad ru peblanka cvetko tešović1, aleksandar mezga1 and bosiljka glumac2 ab stra ct the kirmenjak locality of western istria, croatia, represents the oldest evidence of a dinosaur presence on the adriatic-dinaridic carbonate platform (adcp). in a quarry at this locality, almost a thousand sauropod footprints are recognized in one distinctive trackbearing horizon within the upper tithonian limestones. the stable isotopes of oxygen and carbon, in conjunction with microfacies analysis of carbonate rocks exposed in this quarry, unravel details about the marginal marine or coastal environments in which sauropods left their footprints. rocks from the trackbearing horizon, and laterally adjacent area, represent intertidal fenestral mudstones that form the top of a shallowing-upward succession, capped with a thin peloidal packstone/grainstone layer and overlain by subtidal mudstone. the formation and preservation of footprints was favoured by short-duration exposure of muddy sediment and its rapid burial beneath more mud. the isotopic composition of the sample from the trackbearing horizon is not substantially different from those of an adjacent area without footprints and from the overlying mudstone. stable isotope analysis supports petrographic observations that the conditions on the carbonate tidal fl at during formation of rocks with dinosaur footprints were not unique. documented variations in stable isotope compositions refl ect minor differences in the depositional and diagenetic history of the kirmenjak quarry succession. keywords: stable isotopes, palaeoenvironments, sauropods, upper tithonian limestones, istria, croatia. 1 department of geology, faculty of science, university of zagreb, horvatovac 102a, hr-10 000 zagreb, croatia; (bcvetko@geol.pmf.hr, amezga@geol.pmf.hr) 2 department of geology, smith college, northampton, massachusetts 01063, usa; (bglumac@email.smith.edu) stable isotope analysis of upper tithonian limestones with dinosaur footprints from kirmenjak quarry (istria, croatia) geologia croatica 61/1 3–9 8 figs. 0 tabs. zagreb 2008 geologia croaticageologia croatica � 01 tesovic-mezga-glumac.indd 301 tesovic-mezga-glumac.indd 3 24.6.2008 11:04:4124.6.2008 11:04:41 geologia croatica geologia croatica 61/1 4 dal sau ro pod di no sau rs le ft their foot prin ts du ri ng the la te tit ho nian (mezga et al., 2007). the stu dy was car ried out on a por tion of the kir me njak quar ry de po si ts (fig. 2) that be lo ng to the in for mal kir me njak unit (velić & tišljar, 1988). the fo cus was on a ho ri zon wi th abun da nt di no saur foot prin ts lo ca ted ap proxi ma te ly in the mid dle of the suc cession (fi gs. 2, 3). 2. methods fiel dwo rk in vol ved mea su ri ng, des cri bi ng and sam pli ng of a 14.5 metre thi ck suc ces sion of up per tit ho nian car bo na te roc ks (fig. 2) in the kir me njak quar ry. pet rog rap hic ana lysis was used to fur ther des cri be ro ck types pre se nt and to iden ti fy sam ples for stab le iso to pe ana lysis, whi ch we re col lec ted by the dril li ng of a sma ll amou nt of car bo na te powder wi th a mic rod ri ll moun ted on a bi no cu lar mic ros co pe. all sam ples for stab le iso to pe ana lyses we re roas ted at 380°c for one hour to re mo ve vo la ti le or ga nic mat ter, reac ted wi th 100% h3po4 at 70°c for 5 mi nu tes and ana lyzed usi ng an on-li ne, au to mated car bo na te pre pa ra tion system (kie ll iii) lin ked to a finnigan-mat deltaxl+ ra tio ma ss spec tro me ter at the uni ver si ty of mas sac hu set ts, amherst, usa. stan da rd iso ba ric and phospho ric acid frac tio na tion cor rec tio ns we re ap plied to all re sul ts and ana lyti cal pre ci sion was mo ni to red throu gh dai ly ana lysis of a va rie ty of car bo na te stan dar ds. 3. geological setting the stra tig rap hy and the tec to nic and geo lo gi cal his to ry of is tria are sum ma rized in the expla na to ry no tes to the ba sic geo lo gi cal map of croa tia, sheet ro vinj (polšak & šikić, 1973). de tai led lit ho fa cies and bio fa cies in ves ti ga tio ns of shallow wa ter car bo na tes in is tria we re car ried out in the 1970s and the li st of im por ta nt re fe ren ces can be fou nd in velić et al. (2003). the is trian stra tal suc ces sion can be di vi ded in to fi ve se dimen ta ry uni ts or lar ge-sca le sequen ces boun ded by im por ta nt dis con ti nui ties rep re sen ti ng emer sion sur fa ces of va ryi ng du ration (velić et al., 2003). the se lar ge-sca le sequen ces or me ga sequen ces are: (1) bat ho nian–lower mo st kimmerid gian, (2) up per tit ho nian–lower or up per ap tian, (3) up per al bian–up per san to nian, (4) eo ce ne, and (5) qua ter na ry. the in ves ti ga ted stra ta from the kir me njak quar ry be lo ng to the se co nd tran sgres si ve-reg res si ve me ga sequen ce (up per tit ho nian–lower or up per ap tian), de po si tion of whi ch started in the la te tit ho nian wi th shal lowi ng-u pwa rd li mes to ne cycles for med in sub ti dal, in ter ti dal and sup ra ti dal en vi ronmen ts (velić et al., 2003; vlahović et al., 2003). this li mes to ne is known as the ar chi tec tu ra l-buil di ng sto ne »piet ra d’is tria« or »kir me njak«. the de po si ts of the kir me njak unit exa mi ned in this stu dy (fig. 2) rep re se nt al ternation of metre sca le shal lowi ng-u pwa rd cycles com po sed of bla ck peb ble brec cias or stylo li ti zed mud sto ne at the ba se, over lain by fe nes tral mud sto ne, and com mon ly cap ped by pe loi dal pac ksto ne and/or grain sto ne (velić & tišljar, 1988; tišljar et al., 1995; mezga et al., 2007). the pre sen ce of bla ck peb ble brec cias sug ges ts that stra ta expo sed at the kir me njak lo ca li ty li ke ly be lo ng to the lower pa rt of the kir me njak unit, i.e. to the lower mo st pa rt of the se co nd is trian me ga sequen ce (velić & tišljar, 1988). 4. ichnology the in ves ti ga ted si te is ve ry ri ch in di no saur foot prin ts: al mo st a thou sa nd in di vi dual prin ts ha ve been ob ser ved on the trac kbea ri ng layer expo sed in the kir me njak quar ry (mezga et al., 2007; fig. 3). mo st of the foot prin ts ha ve an oval or hor ses hoe sha pe wit hout clear ly vi sib le di git im pres sio ns (fig. 4), and are re la ti ve ly shal low (1–2 cm). the ova l-sha ped prin ts rep re se nt pes prin ts and the hor ses hoe-sha ped prin ts are ma nus prin ts (fig. 4). the foot prin ts are of va rious di men sio ns: the ma nus prin ts ha ve a len gth ran gi ng from 5.5–26.5 cm, and the pes prin ts from 23–52 cm. the calculated hip heig ht ran ges from 153–306 cm. the re are 23 trac kways do cu men ted at this si te and they frequen tly over lap. the trac kways show cha racte ris ti cs of a nar row-gau ge type (fig. 5). the pa ce and stri de lengths in di ca te slow wal ki ng in di vi dua ls. the main di rec tion of di no saur mo ve me nt is towar ds the ne and be cau se the re are ma ny pa ral lel trac kways it may be con clu ded that so me of the in di vi dua ls we re mo vi ng to get her in a he rd (in di ca tion of grega rious be ha vior). althou gh the sta te of pre ser va tion is far from ideal, the prin ts be lo ng to sau ro pod di no sau rs ba sed on their ove ra ll mor pho lo gy (mez ga et al., 2007). the foot prin ts are si mi lar to pa rab ron to po dus ic hno ge nus and the ic hno coe no sis is as signed to the bron to po dus ic hno fa cies, whi ch is cha rac te ri zed by sau ro pod foot prin ts in car bo na te plat fo rm en vi ron men ts. 5. lithology and microfossil assemblage seve ral shal lowi ng-u pwa rd cycles are dis tin guis hed in the in ves ti ga ted suc ces sion, ran gi ng in thic kne ss from 0.3 to 2 m fi gu re 1: geog rap hic and geo lo gic set ti ng of the kir me njak lo ca li ty in is tria, croa tia (mo di fi ed af ter velić et al., 1995). 01 tesovic-mezga-glumac.indd 401 tesovic-mezga-glumac.indd 4 24.6.2008 11:04:4224.6.2008 11:04:42 geologia croatica 5 blanka cvetko tešović et al.: stable isotope analysis of upper tithonian limestones with dinosaur footprints from kirmenjak quarry (fig. 2). the shal lowi ng-u pwa rd cycles be gin wi th bla ck peb ble brec cia (in two cycles) or stylo li ti zed mud sto nes, fol lowed by fe nes tral mud sto ne, and com mon ly end wi th pe loidal pac ksto ne/grainstones and grain sto nes (fig. 6). the mudsto nes are mas si ve, hig hly stylo li ti zed (fig. 6), oc ca sional ly bio tur ba ted, ra re ly la mi na ted, lig ht yel lowi sh gray in co lour, and in pla ces in ter bed ded wi th len ses and laye rs of pe loi dal pac ksto ne to grain sto ne. ra re fos si ls in clu de os traco ds, green al gae, gas tro po ds, sma ll fo ra mi ni fe ra and crus tacean pel le ts fav rei na. the se de po si ts are in ter pre ted as rep rese nting a sub ti dal en vi ron me nt, pro bab ly a res tric ted la goon. bla ck peb bles (fig. 6) in cor po ra ted in the ba se of so me mud sto ne ho ri zo ns sug ge st rewor ki ng of mar sh de po si ts du ri ng sea-le vel ri se. mud sto nes com mon ly gra de upwa rd in to fe nes tral mud sto ne (fi gs. 2 & 6). the fe nes tral mud sto nes (fig. 6) are in pla ces al so in terbed ded wi th len ses and laye rs of pe loi dal pac ksto ne to grainsto ne wi th mm-sca le mud dy in trac las ts. com mon mm-sca le fi gu re 2: sche ma tic lit ho lo gic co lu mn of the mea su red kir me njak quar ry suc ces sion wi th mea su red d13c and d18o va lues. on ly exam ples of pro mi ne nt shal lowi ng-u pwa rd suc ces sion to ps are in di ca ted on the stra tig rap hic co lu mn. 01 tesovic-mezga-glumac.indd 501 tesovic-mezga-glumac.indd 5 24.6.2008 11:04:4224.6.2008 11:04:42 geologia croatica geologia croatica 61/1 6 fe nes tral voi ds are fi l led wi th spa ri te and are main ly ir re gu lar in sha pe, whe reas la mi nar fe nes trae or sheet crac ks are not as abun da nt. sub ver ti cal to ir re gu lar mmto cm-sca le de sic cation and dis so lu tio n-en lar ged voi ds wi th geo pe tal in fi l ls of va do se si lt and coar se-crystal li ne clear equa nt cal ci te ce me nt are pre se nt in so me of the fe nes tral mud sto nes (fig. 6). the fe nes tral mud sto nes ra re ly fo rm in si tu brec cia ted shal lowi ngu pwa rd cycle to ps wi th rewor ked mud dy in trac las ts. the fe nestral mud sto nes are in ter pre ted as having for med in res tric ted shal low sub ti dal to in ter ti dal en vi ron men ts and they com mon ly gra de upwa rd in to pe loi dal grain sto ne (fig. 6). the pe loi dal pac ksto ne/grainstones to grain sto nes (fig. 6) are cha rac te ri zed by abun da nt ir re gu lar fe nes trae and com mon in ter va ls wi th mm-sca le in trac las ts that fo rm dar ker grayi sh to browni sh co loured shal lowi ng-u pwa rd cycle to ps wi th in si tu brec cia tion. the se cycle to ps are al so cha rac te rized by dar ke ned clas ts (bla ck peb bles), mmto cm-sca le de sicca tion and dis so lu tio n-en lar ged voi ds wi th geo pe tal in fi l ls (fig. 6), thin cal cre te crus ts, and cm-sca le clay-ri ch ca ps. the pe loi dal pac ksto ne/grainstones to grain sto nes from the up permo st par ts of shal lowi ng-u pwa rd cycles are in ter pre ted as de po si ts of in ter ti dal to sup ra ti dal en vi ron men ts for med by hi gh ener gy sto rm wa ves and ti des. mo di fi ca tio ns un der su baerial expo su re con di tio ns pro du ced cha rac te ris tic cycle to ps. sam ples from the trac kbea ri ng ho ri zon and ad ja ce nt area wit hout foot prin ts are lit ho lo gi cal ly ve ry si mi lar. they con si st of mud sto nes wi th sma ll fe nes trae, fai nt la mi na tion and rat her lar ge sub ver ti cal to ir re gu lar de sic ca tion crac ks and voi ds. the up per mo st pa rt of bo th con sis ts of a thin layer of pe loi dal pac ksto ne/grainstone (fig. 6). laye rs di rec tly over lyi ng the foot pri nt ho ri zon, on the ot her ha nd, are qui te dif fe re nt – they are mas si ve stylo li tic mud sto nes. the pre sen ce of fe nes trae and de sic ca tion fea tu res sug ges ts that the roc ks wi th di no saur foot prin ts we re for med in an in ter ti dal en vi ron me nt. the la ck of fe nes trae and ot her in di ca to rs of su bae rial expo su re in the mud sto nes abo ve the foot prin ts sug ge st for ma tion in a sub tidal en vi ron me nt. thus, the foot prin ts for med on top of a shallowi ng-u pwa rd suc ces sion (fig. 6), whi ch is over lain by dee per, sub ti dal de po si ts. palaeoen vi ron men tal con di tio ns du ri ng de po si tion of the kir me njak quar ry suc ces sion were not op ti mal for hi gh bio tic pro duc ti vi ty. mic ro fos sil re mai ns in clu de on ly a few taxa of cal ca reous al gae, whi le ben thic fo ra mi ni fe ra are ve ry ra re. the mic ro fos sil as sem bla ge (fig. 7) con sis ts of cam pbel liel la fi gu re 3: pa no ra mic view of the trac kbea ri ng ho ri zon in the kir me njak quar ry. fi gu re 4: an ova l-sha ped pes pri nt (lower pa rt of the pho tog ra ph) and a hor ses hoe-sha ped ma nus pri nt (up per pa rt of the pho tog ra ph) of the sau ro pod dinosaur from the kir me njak quar ry. fi gu re 5: a nar row-gau ge trac kway of a sau ro pod di no saur from the kir me njak quar ry. 01 tesovic-mezga-glumac.indd 601 tesovic-mezga-glumac.indd 6 24.6.2008 11:04:4324.6.2008 11:04:43 geologia croatica 7 blanka cvetko tešović et al.: stable isotope analysis of upper tithonian limestones with dinosaur footprints from kirmenjak quarry stria ta (carozzi) (fig. 7a), fav rei na sp. (fig. 7b) and sal pin go po rel la an nu la ta carozzi (fig. 7c-d), as we ll as other uniden ti fi ed fo ra mi ni fe ra, gas tro po ds, os tra co ds and ec hinoi ds. the iden ti fi ed mic ro fos sil as sem bla ge, typi cal of the kir me njak unit, con fi r ms a la te tit ho nian age. 6. stable isotope results stab le iso to pe va lues of the 32 sam ples ana lyzed from the stu died suc ces sion (fi gs. 2 & 8) are lower than the es tima ted va lues of up per ju ras sic unal te red ma ri ne cal ci te (δ18o = -2 to -1‰; δ13c = +3 ‰; loh ma nn & wal ker, 1989). all sam ples ha ve po si ti ve δ13c va lues exce pt for the three who lero ck sam ples of pe loi dal pac ksto ne-grain sto ne from be low a pro mi ne nt su bae rial expo su re ho ri zon wi th bla ck peb bles in the mid dle of the sec tion (fig. 2). the re st of the da ta poin ts show a ge ne ral co va rian ce be tween δ13c and δ18o va lues, and an over lap be tween com po si tio nal fi el ds rep re sen ti ng dif fe re nt ro ck types (fig. 8). mud sto nes, howe ver, te nd to clus ter towar ds mo re ne ga ti ve δ13c and δ18o va lues, and fe nes tral mud sto nes and pe loi dal pac ksto ne-grain sto nes plot towar ds mo re po si ti ve va lues (fig. 8). excep tio ns are one fe nes tral mud sto ne sam ple (δ13c = 0.28 ‰) and one mud sto ne sample (δ13c = 1.48 ‰) from the ba se of a shal lowi ng-u pwa rd suc cession. the sam ple wi th di no saur foot prin ts is not sub stan tial ly dif fe re nt from tho se of the ad ja ce nt area wit hout foot prin ts and from the over lyi ng mud sto ne (fig. 8). 7. discussion pet rog rap hic ob ser va tio ns do not explain why the re are no foot prin ts alo ng the sa me in ter ti dal ho ri zon in dif fe re nt pla ces in the quar ry. it is pos sib le that the foot pri nt dis tri bu tion refl ec ts mi nor dif fe ren ces in wa ter dep th, whi ch are not refl ected by lit ho lo gi cal chan ges. it is al so pos sib le that foot prin ts we re not ob ser ved in ot her si mi lar ro ck types in the quar ry be cau se mo st of the ot her to ps of the shal lowi ng-u pwa rd suc ces sio ns are now cap ped by pro mi ne nt stylo li tes and thus the foot prin ts, if they we re the re, may ha ve been ob li te ra ted by pres su re dis so lu tion alo ng stylo li tes. bed-pa ral lel stylo li tes are extre me ly abun da nt in the kir me njak de po si ts, and lo cal ly the se stra ta are com mon ly re fer red to as the stylo li tic li mes to nes. the ob ser ved abundan ce and mor pho lo gy of stylo li tes all poi nt towar ds a po tentail ly sub stan tial mag ni tu de of pres su re dis so lu tion and thickne ss re duc tion of the kir me njak stra ta du ri ng bu rial dia ge ne sis. am pli tu de of stylo li tes sug ges ts that the pri ma ry thic kne ss of the se tit ho nian li mes to nes may ha ve been re duced by about 20–23% (tišljar, 1978). fur ther mo re, it may be sig ni fi ca nt that the shal lowi ngu pwa rd suc ces sion wi th di no saur foot prin ts ter mi na ted in fe nes tral mud sto ne (wi th on ly a ve ry thin cap of pe loi dal pac ksto ne/grainstone; fig. 6) rat her than in thic ker shal low in ter ti dal to sup ra ti dal grain sto ne de po si ts wi th sub stan tial evi den ce for mo di fi ca tion du ri ng su bae rial expo su re. footprin ts li ke ly ha ve a bet ter po ten tial of bei ng pro du ced and pre ser ved in mud dy (rat her than grai ny) se di me nt that was dried out du ri ng a rat her brief pe riod of expo su re in an in ter tifi gu re 6: de tai ls of shal lowi ng upwa rd cycles from the cen tral pa rt of the mea su red kir me njak suc ces sion (see al so fig. 2). the cycles be gin wi th bla ck peb ble brec cias (a) or stylo li ti zed mud sto ne (a’), over lain by fe nes tral mud sto ne (b) and pe loi da l-in trac las ti c-fe nes tral pac ksto ne wi th geo pe tal in fi ll (c), and cap ped wi th thin pe loi da l-in trac las tic grain sto ne (d) wi th di no saur foot prin ts (e). 01 tesovic-mezga-glumac.indd 701 tesovic-mezga-glumac.indd 7 24.6.2008 11:04:4624.6.2008 11:04:46 geologia croatica geologia croatica 61/1 8 dal en vi ron me nt and was then ra pid ly co ve red by sub ti dal mud. the ab sen ce of sub stan tial pres su re dis so lu tion (stylo lites) alo ng the bed di ng pla ne wi th foot prin ts, unear thed by quar ry ope ra tio ns, fur ther ai ded foot pri nt pre ser va tion. stab le iso to pe re sul ts sup po rt pet rog rap hic ob ser va tio ns that the ho ri zon wi th di no saur foot prin ts does not rep re se nt a unique ro ck type. com pa ri son wi th unal te red ju ras sic ma ri ne ce men ts and the co varian ce be tween δ13c and δ18o va lues (fig. 8), sug ge st po st-de po si tio nal or dia ge ne tic mo di fi ca tio ns in the pre sen ce of me teo ric wa te rs. this is al so sup por ted by the pre sen ce of dis so lu tion en lar ged voi ds and their oc clu sion by va do se si lt and me teo ric cal ci te ce me nt (fig. 6). ne ga ti ve δ13c va lues re cor ded in the pe loi dal pac ksto ne-grain sto ne (fi gs. 2 & 8) as so cia ted wi th the expo sed sur fa ce wi th bla ck peb bles, refl e ct dia ge ne sis un der su bae rial con di tio ns in the pre sen ce of ter res trial ly de ri ved de cayi ng orga nic mat ter. va ria tio ns in δ13c and δ18o va lues in ot her ana lyzed sam ples (fig. 8) are li ke ly a fun ction of mi nor va ria tio ns in con di tio ns du ri ng de posi tion (tem pe ra tu re, sa li ni ty, or ga nic pro duc ti vi ty), and the exte nt of dia ge ne tic mo di fi ca tio ns. the ob ser ved over lap of com po si tio nal fi el ds sug ges ts that the ove ra ll con di tio ns du ri ng de po si tion and dia ge ne sis of va rious ro ck types did not va ry great ly in deed. the clus te ri ng of fe nes tral mud sto nes (a nd the re st of the pe loi dal pac ksto ne to grain sto ne sam ples) towar ds slig htly mo re po si ti ve va lues, may refl e ct their lit hi fi ca tion from wa te rs that expe rien ced en han ced exchan ge wi th the atmos phe re (in clu di ng eva po ra tion) du ri ng their re si den ce on the car bo na te ti dal flat. on the ot her ha nd, clus te ri ng of mud sto ne towar ds slig htly mo re ne ga ti ve va lues may in di ca te lit hi fi ca tion in the pre sen ce of a so mewhat grea ter amou nt of or ga nic mat ter in the se res tric ted sub ti dal/lagoonal de po si ts. the be gin ni ng of de po si tion of the kir me njak unit is mar ked by an os cil la to ry tran sgres sion over the emer ged re lief (tišljar et al., 1995; velić et al., 2003). de po si ts in the lower pa rt of the kir me njak unit in di ca te the pre sen ce of coastal mar sh en vi ron men ts, whi ch rep re se nt the sour ce for bla ck peb ble brec cias (vlahović, 1999). wi th con ti nui ng tran sgres sion, the se mar shes we re gra dual ly rep la ced wi th shal low, pro tec ted la goon en vi ron men ts sur roun ded by wi de ti dal fl a ts whe re di no sau rs le ft their foot prin ts. 8. conclusion the kir me njak quar ry in wes te rn is tria, croa tia, is cur ren tly the lar ge st di no saur foot pri nt si te on the adcp wi th al mo st a thou sa nd in di vi dual foot prin ts pre ser ved in up per tit ho nian li mes to nes. di no saur foot prin ts we re pro du ced on the top of a shal lowi ng-u pwa rd suc ces sion in in ter ti dal fe nes tral mud stones, cap ped wi th a thin pe loi dal pac ksto ne/grainstone layer, and over lain by sub ti dal mud sto ne. foot pri nt for ma tion and pre ser va tion was fa voured by sho rt-las ti ng expo su re of mud dy se di me nt and its ra pid bu rial be nea th mo re mud. the ab sen ce of sub stan tial pres su re dis so lu tion (stylo li tes) alo ng the bed di ng pla ne wi th foot prin ts, unear thed by quar ry ope ra tio ns, fur ther ai ded foot pri nt pre ser va tion. the re sul ts of pet rog raphic and stab le iso to pe ana lysis did not pro vi de any di re ct evi den ce that the con di tio ns on the car bo na te ti dal fl at du ri ng for ma tion of the de po si ts wi th di no saur foot prin ts we re unique. do cu men ted va ria tio ns in stab le iso to pe com po sitio ns, on the ot her ha nd, refl e ct mi nor dif fe ren ces in the de posi tio nal and dia ge ne tic his to ry of stra ta from this stra tig rap hic suc ces sion. ac knowled gmen ts this re sear ch was pa rt of the joi nt re sear ch pro je ct no. 7krpj065729 »palaeos tu dies and re con struc tio ns of di no saur po pu la tio ns and their en vi ron men ts in is tria and ad ja ce nt is lan ds (croa tia) du ri ng the la te ju ras sic and cre ta ceous fi gu re 8: d13c vs. d18o va lues of the ana lyzed sam ples. fi gu re 7: mic ro fos sil as sem bla ge of the kir me njak unit from the kir me njak quar ry. a, lon gi tu di nal and tran sver se sec tio ns of cam pbel liella stria ta (ca roz zi); b, fe nes tral mud sto ne wi th com mon fav rei na sp.; c, al gal mud sto ne wi th tran sver se sec tio ns of sal pin go po rel la an nu la ta carozzi; and d, al gal mud sto ne wi th va rious sec tio ns of s. an nu la ta carozzi. 01 tesovic-mezga-glumac.indd 801 tesovic-mezga-glumac.indd 8 24.6.2008 11:04:4724.6.2008 11:04:47 geologia croatica 9 blanka cvetko tešović et al.: stable isotope analysis of upper tithonian limestones with dinosaur footprints from kirmenjak quarry pe rio ds (170–90 ma)« spon so red by the swi ss na tio nal scien ce foun da tion. the wo rk was al so sup por ted by gran ts from the croa tian mi nis try of scien ce, edu ca tion and spo rt (pro je ct nos. 119–1191152–1169 and 19–1191152–1171). fi nan cial sup po rt was al so pro vi ded by the stride fel lowship prog ram at smi th col le ge and by re sear ch gran ts from the mel lon foun da tion and from the wo me n’s in ter natio nal scien ce col la bo ra tion (wisc) prog ram of the ame rican as so cia tion for the ad van ce me nt of scien ce, fun ded by the u.s. na tio nal scien ce foun da tion, ad mi nis te red throu gh smi th col le ge. our spe cial than ks go to d. pu ti nja, m. hva la and ot her em ployees of »ka men pa zin d.d.«. we are than kful to c. tewksbu ry (stride fel lowship prog ram at smi th col le ge) for her as sis tan ce wi th sam ple pro ces si ng and ini tial da ta in teg ra tion, to t. cal da na ro (smi th col le ge) for his he lp wi th thin sec tion pre pa ra tion, and to dr. s. bur ns (uni ver si ty of mas sac hu set ts, am her st, usa) for stab le iso to pe ana lyses. 9. references lohmann, k.c & walker, j.c.g. (1989): the d18o re co rd of phane ro zoic abio tic ma ri ne cal ci te ce men ts. – geop hysi cal re sear ch let te rs, 16, 319–322. mezga, a., bajraktarević, z., cvetko tešović, b. & gušić, i. (2003): fir st re co rd of the di no sau rs in the la te ju ras sic se di men ts of is tria, croa tia. – in: windolf, r. & sachs, s. (e ds.): ab strac ts of the fir st mee ti ng of eu ro pean ver teb ra te pa leonto lo gis ts, ba sel, 30. mezga, a., cvetko tešović, b. & bajraktarević, z. (2007): fir st re co rd of the di no sau rs in the la te ju ras sic of the ad ria ti cdi na ri dic car bo na te plat fo rm (croa tia). – pa laios, 22/2, 188–199. polšak, a. & šikić, d. (1973): os nov na geo loška kar ta 1:100.000, tu mač za li st ro vinj [geo lo gy of ro vinj sheet – in croatian]. – insti tut za geo loška is traživa nja zag reb (1963), sa vez ni geo loški zavod, beog rad, 51p. tišljar, j. (1978): ti dal fl at and shal low ma ri ne car bo na te se di men ts in the up per ju ras sic and cre ta ceous of is tria (yu gos la via). – ac ta geo lo gi ca, 9/5, 159–194. tišljar, j., vlahović, i., matičec, d. & velić, i. (1995): platfor mni fa ci je si od gor njeg ti tona do gor njeg al ba u za pad noj is tri i pri je laz u tem pes tit ne, kli no for mne i ru dis tne bio li tit ne fa ci je se donje ga ce no ma na u južnoj is tri (ek skur zi ja b) [plat fo rm fa cies from the up per tit ho nian to up per al bian in wes te rn is tria and tran sition in to tem pes ti te, cli no fo rm and ru di st bio lit hi te fa cies of the lower ce no ma nian in sout he rn is tria (excur sion b) – in croa tian]. – in: vlahović, i. & velić, i. (e ds.): 1st croa tian geo lo gi cal con gre ss, excur sion gui de-book, 67–110. velić, i. & tišljar, j. (1988): litostratigrafske jedinice u dogeru i malmu zapadne istre (zapadna hrvatska, jugoslavija) [lithostratigraphic units in the dogger and malm of western istria (western croatia, yugoslavia) – in croatian]. – geološki vjesnik, 41, 25–49. velić, i., tišljar, j., matičec, d. & vlahović, i (1995): opći pri kaz geo loške građe is tre [a re view of the geo lo gy of is tria – in croa tian]. – in: vlahović, i. & velić, i. (e ds.): 1st croa tian geo lo gi cal con gre ss, excur sion gui de-book, 5–30. velić, i., tišljar j., vlahović, i., matičec, d. & bergant, s. (2003): evo lu tion of the is trian pa rt of the ad ria tic car bo na te plat fo rm from the mid dle ju ras sic to the san to nian and for ma tion of the flysch ba sin du ri ng the eo ce ne: main even ts and re gio nal com pa ri son. – in: vlahović, i. & tišljar j. (e ds.): evo lu tion of de po si tio nal en vi ron men ts from the pa lae zoic to the qua ter na ry in the kar st di na ri des and the pan no nian ba sin. 22nd ias mee ti ng of se di men to lo gy, opa ti ja, fie ld trip gui de book, 3–17. vlahović, i. (1999): kar bo nat ni fa ci je si plit ko vod nih ta ložnih sus tava od ki me ridža do gor nje ga al ba u za pad noj is tri [car bo na te fa cies of shal low wa ter de po si tio nal syste ms from kim me rid gian to the up per al bian in wes te rn is tria – in croa tian wi th exten ded engli sh sum ma ry]. – un pub lis hed phd the sis, fa cul ty of mi ni ng, pet roleum and geo lo gy, uni ver si ty of zag reb, 327 p. vlahović, i., tišljar, j., velić, i., matičec, d., skelton, p.w., korbar, t. & fuček, l. (2003): main even ts in the se dimen ta ry suc ces sion of the ad ria tic car bo na te plat fo rm from oxfordian to the up per san to nian in is tria. – in: vlahović, i. & tišljar j. (e ds.): evo lu tion of de po si tio nal en vi ron men ts from the pa laeo zoic to the quar ter na ry in the kar st di na ri des and the pan no nian ba sin, 22nd ias mee ti ng of se di men to lo gy, opa ti ja, fie ld trip gui de book, 19–56. vlahović, i., tišljar, j., velić, i., & matičec, d. (2005): evolu tion of the ad ria tic car bo na te plat fo rm: pa laeo geog rap hy, main even ts and de po si tio nal dyna mi cs. – pa laeo geog rap hy, pa laeoc li mato lo gy, pa laeoe co lo gy, 220, 333–360. ma nus cri pt re cei ved oc to ber 10, 2007. re vi sed ma nus ci pt ac cep ted ja nua ry 18, 2008. 01 tesovic-mezga-glumac.indd 901 tesovic-mezga-glumac.indd 9 24.6.2008 11:04:4824.6.2008 11:04:48 01 tesovic-mezga-glumac.indd 1001 tesovic-mezga-glumac.indd 10 24.6.2008 11:04:4924.6.2008 11:04:49 raslan&haroun.indd 333 � ab stra ct quaternary sediments of the north fayium depression, are mainly represented by residual soil and calcrete, and have been found to be anomalously radioactive. these sediments are deposited on the irregular surface of the carbonaceous shale of the middle member of the oligocene qatrani formation in the northern part of the fayium depression. a mineralogical investigation involving a preliminary microscopic examination and detailed environmental scanning electron microscope (esem) has revealed the presence of several heavy accessory minerals. these include zircon, apatite, ilmenite, rutile and garnet as persistent detrital minerals. in addition, a highly suspected secondary uranium mineral has been identifi ed between some mica fl akes. while uranium in the bed rock does not exceed 3.7 ppm, its assay in the residual soil varies from 20 to 200 ppm with an average of 94 ppm, whereas the analyzed two samples of calcrete assay 85 and 122 ppm. trace element analysis in the studied rock types indicates enrichment in zn, zr, y, sr and v. keywords: radioactive quaternary sediments, residual soil, calcrete, zircon, apatite, western desert, egypt geology and mineralogy of the radioactive quaternary sediments of the north fayium depression, western desert, egypt � mohamed f. raslan and yehia s. haroun nuclear materials authority, p.o. box 530, el maadi, cairo, egypt; (ralangains@hotmail.com) doi: 104154/gc.2010.27 geologia croatica 63/3 333–343 8 figs. 2 tabs. zagreb 2010 geologia croaticageologia croatica 1. introduction uranium occurrence in the quaternary surfi cial sediments of the north fayium depression (residual soil and calcrete) has only recently been discovered and classifi ed. the occurrence is typically young and has been developed when uranium was extracted or precipitated from shallow ground or surface waters. on the surface of bench scarps that form the fayium depression, the quaternary sediments which represent the host rock of the radioactive anomalies are indeed arid land deposits (residual soil and calcrete) that have been laid upon the eroded surface of the carbonaceous shale of the middle member of the oligocene qatrani formation. carbonaceous sediments denote rocks that contain original organic tissues and/or their decomposition products and their fl uid derivatives and extracts have been deposited under anaerobic conditions (pettijohn, 1975). the carbonaceous shale of the fayium depression has been the point of interest of many studies from zeid & monem (1957), cameron (1967), mostafa (1972), morsy (1978), el shazly et al. (1974) to haroun (2001) and more recently to mousa & haroun (2005). the arid climate of the fayium depression (haroun, 2001) has helped in the formation of the residual soil because this climate accelerates the weathering processes on the qatgeologia croatica 63/3geologia croatica 334 rani formation involving sandstone, clays and limestone beds. in addition, the arid conditions have also facilitated formation of the duricrust sediments (calcrete) associated with the residual soil. the calcrete sediments occur in general in the form of a thin crust of sand cemented by calcite. morphologically, this crust is cavernous, spongy, semi friable and pale white in colour, besides being characterized by a highly irregular surface. carlisle (1983) mentioned that deposition of calcrete results from common ion precipitation when ca/mg sulfate or chloride brines are enriched in salt lakes or in local highly evaporative domains. in the study area, calcrete is of a non pedogenic type and has resulted by lateral transport of soluble ions towards favourable sites of deposition. this also makes it a favourable site for uranium concentration from the different poor source areas into the relatively compact duricrust body, (el-sayed et al., 2000). the present work is mainly concerned with both the geological and mineralogical characteristics of the quaternary sediments of the north fayium depression that have been deposited on the irregular surface of the carbonaceous shale. besides the necessary fi eld geological studies, mineralogical investigation of some mineralized samples has involved proper mineral separation and esem analysis of separated pure minerals. in addition, the uranium occurrence in these sediments would be identifi ed as well as the general genetic aspects of this mineralization. this involved the study of detrital heavy accessory minerals as another source for uranium in carbonaceous shale. 2. geology of the el fayium depression the study area is located at 30º 35′ long e and 29º 37′ lat., and is considered as part of the fayium depression the general geology of which is illustrated in figure 1. it consists mainly of sedimentary rocks of upper eocene, oligocene, early miocene and quaternary ages. the oldest rocks exposed in the study area belong to the upper eocene and mainly include the qasr el sagha formation which covers the southern part of the study area (fig. 1). this formation is composed of sand with some gypsiferous clay, and interbedded with fossiliferous limestone in the middle part of the section. the subsequent oligocene rocks are represented by the qatrani formation which covers the middle part of the study area and is mainly composed of a succession of variegated sands and sandstones with alternating beds of clays, shale and limestone. carbonaceous shale occurs in the form of lenticular masses within the sand and sandstone beds of the qatrani formation. 2.1. bed rock geology the study area is considered as a locally closed swamped area and is stratigraphically composed from the base upwards of fi ne-grained sandstone, silt, sandy clay and clay. this sequence is topped by a carbonaceous shale bed that occurs in the form of lenses of variable thickness ranging from 2 to 7 m, and is characterized by lateral transition into green shale and clay. the sandstone bed covers a great part of the study area, and extends to the south and south west, while the radioactive carbonaceous bed is confi ned to certain parts of the upper red fi ne grained sandstone (fig. 2). the sandstone bed is underlain by siltstone and limestone beds of fl uvio-marine origin. pejatovic (1968) stated that this red sandstone sequence was deposited under arid conditions where lithogenesis occurred under conditions where evaporation was more rapid than water percolation. this sandstone is enriched in carbonate and sulphate minerals including gypsum. the carbonaceous shale covers an area of about 35 km2 in the northeastern part of the study area and forms a locally enclosed swamp area (haroun, 2001; mousa & haroun, 2006). lithologically, the carbonaceous shale bed was deposited within the upper member of the qatrani formation of oligocene age. as shown in figure 3, the carbonaceous shale bed is occasionally recorded within the sequence composed of sandy clay, silt, clay and fi ne grained sandstone, which represents fl ood plain fl uorine sediment (reineck & singh, 1973). the radioactive shale is purple, black, brown, ferruginous, highly enriched in gypsum, and 5–7 m thick. the depositional environment of the radioactive carbonaceous shale must have involved a stagnant small basin, characterized by the following criteria: 1 – a highly reducfigure 1: geologic map of fayium depression. raslan and haroun: geology and mineralogy of the radioactive quaternary sediments of the north fayium depression, western desert, egypt geologia croatica 335 ing environment enriched in anaerobic bacteria, organic matter, pyrite and iron content; 2 – a low carbonate content; 3 – an unusual concentration of some heavy metals including v, zn, cu and cr; 4 – absence of currents (pettijohn, 1975). 2.2. geology of the radioactive quaternary sediments the quaternary deposits which are represented in the study area by residual soil and calcrete, cover the middle part of the study area and extend southward for about 2km (fig. 2). these deposits cut the oligocene red sandstone sediments of the qatrani formation at a topographic elevation of 194 m a.s.l. and are about 2 m thick. towards the southeast, the quaternary deposits are at a topographic elevation of 168 m (fig. 2). 2.2.1. residual soil in the study area, the residual soil is associated with a duricrust (locally present in the central part of the deposit) and occupies an area of about 4 km2 in the north eastern part of the mapped area (fig. 2). it is bounded to the south by bedrock composed of fi ne grained reddish silty sandstone that belongs to the upper part of the qatrani formation. the residual soil is indeed the product of in situ weathering of some parent rocks that mainly included red sandstone, clay, limestone, gravelly sandstone and basalt. the surfi cial solutions involving meteoric water, surface ground waters as well as hydrothermal solutions have laterally moved across the drainage patterns in the investigated area. these drainage patterns dissect the investigated area and extend northerly into low lying areas (geomorphologically local basin) where the residual soils have been deposited. the drainage lines have thus acted as channels through which the surfi cial solutions were laterally transported. in the local basin, chemical weathering must have been active (oxidation, reduction and ion exchanges) during formation of the residual soils that cover the carbonaceous shale bed. the residual soils are friable and brownish black in colour and are actually rich in roots, rock debris and plant remains. 2.2.2. duricrust (calcrete) the duricrust is characterized by a hard, roughly horizontal and highly irregular surface. it is the product of precipitation of different dissolved or airborne salts and other minerals within the existing soils, unconsolidated sediments as well as in the decomposed or permeable rocks. the calcrete crust is actually the major type of duricrust present in the study area and is considered as a crustation that has been precipitated in the pore space and on the eroded surface of the lower member of the qatrani sandstone. generally, the calcrete crust deposits consist of abundant soil, fi ne grained alluvium, angular sand grains and angular clay fragments, soft sediments or weathered bed rock variably cemented and replaced by authigenic carbonate. many compositional varieties of the calcrete crust exist, and their textures range from banded in the lower part to nodular or cavernous in the upper part of the calcrete crustation. the transition from calcrete to the underlying pelitic detritus (the so-called red sandstone) is general. formation of the calcrete deposits in the study area probably occurred as follows: 1 – leaching of the carbonate and fi ne grained sediments from the limestone and clays of the country rock by ground and/or surface water. 2 – oscillating ground water levels resulted in redeposition or precipitation of the suspended micro-matter, and minerals at different levels within the alluvium and unconsolidated sediments present in the study area. 3. mineralogical and geochemical investigation radiometric studies of fossil trees which grew in the residual soil of the north fayium scarp indicated the presence of anomalous uranium values (haroun & raslan, 2007), which supports the radioactivity of the residual soils and calcrete. uranium from the trees attained 35 ppm while the background of the residual clay and soil in the area does not exceed 3.5 ppm. mohamed (1965) concluded that oligocene rocks of the qatrani formation, which constitute the north fayium succession did not show any uranium anomfigure 2: geologic map of detailed study area (rectangular area in fig. 1). geologia croatica 63/3geologia croatica 336 aly. therefore, it was necessary to study both the mineralogy and the radioactivity of both the residual soil and calcrete sediments of the quaternary rocks in this area. 3.1. sampling and analytical techniques in order to determine the minerals responsible for the high radioactivity in the quaternary deposits of the north fayium depression, two bulk composite samples representing the residual soil and calcrete were prepared and subjected to various mineral separation techniques. these included disintegration (crushing and grinding), followed by heavy liquid separation using bromoform (sp. gr. 2.85 gm/cm3), to estimate and identify the heavy mineral content. monomineralic fractions were prepared from the heavy fraction for preliminary mineralogical investigation and identifi cation using the binocular microscope followed, by detailed examinations using environmental scanning electron microscope (esem) techniques. for this purpose, a philips model xl 30 supported by an energy dispersive x-ray unit (edax) was used. seven rock samples from the residual soil and two samples from the calcrete sediments in the study area were collected, representing the highest values of anomalous fi eld radioactivity. these were prepared for geochemical analysis using the laser method as well as for the determination of some trace elements using x-ray fl uorescence. both the mineralogical investigation and the geochemical analyses were carried out in the laboratories of the egyptian nuclear materials authority. 3.2. mineralogical investigation the accessory heavy minerals indicated that zircon is the most dominant mineral in all the heavy fractions of different studied size classes of the residual soil samples, together with lesser amounts of apatite, garnet, rutile and mica. the heavy fractions of the calcrete crustation sample revealed the presence of zircon, apatite, ilmenite, rutile and garnet. the content of these minerals generally increases with decreasing grain size. the detailed mineralogical and chemical characteristics of the separated heavy accessory minerals from the studied residual soil and calcrete samples of the quaternary sediments are briefl y discussed below. 3.2.1. zircon zircon crystals have actually been detected in both the residual soil and the calcrete crustation samples. these crystals are characterized by considerable variation in shape and size. they are generally colourless, translucent, and are mainly found as persistent heavy accessory detrital mineral species. some grains are elongated with bipyramidal form, while others occur without distinct crystal faces. others are generally subrounded to well round in shape. however, broken, zoned, outgrowths and other parallel aggregate-bearing varieties are generally absent. the back scatter electron images (bse images) show the characteristic habit of the zircon (figs. 4a– c). alternatively, the edax spectrum for the separated zircon grains presented in fig. 5a reflects the chemical com position of the mineral in addition to minor amounts of hf, u and th. finally, the presence of subrounded to well rounded detrital zircon in the studied sediments refl ects the effect of erosional weathering and transportation, indicating probable derivation from both rivers and beaches. 3.2.2. apatite the majority of the separated apatite grains vary in colour from pale to deep brown, and are mainly massive and translucent besides showing a well rounded to subrounded shape. the sem photomicrographs and edax spectra for the apatite grains are presented in figs. 4e&5b for the residual soil sample and figs. 6c & 7b for the calcrete sample. the data refl ects the chemical composition of apatite (ca 59.73%, p 30.85% and si 3.70%), with a relatively appreciable amount of uranium and thorium attaining 1.60 and 1.40% respectively. according to heinrich (1958), uranium usually substitutes for ca in the apatite structure due to the similarity of the ionic radii (ca = 1.06a° and u = 1.05a°). 3.2.3. garnet, rutile and ilmenite the edax scanned spots of a garnet crystal from a residual soil sample shown in figs. 4f and 5c indicate a si content figure 3: composite stratigraphic cross section of qatrani formation including both low and high radioactive shale beds, after (mousa & haroun, 2006). raslan and haroun: geology and mineralogy of the radioactive quaternary sediments of the north fayium depression, western desert, egypt geologia croatica 337 figure 4: sem backscattered electron images for the studied heavy minerals separated fro residual soil sample. a, b, c & d zircon crystalls of various habits, e apatite, f garnet, g rutile, h mica fl ak with interstitial uranium. geologia croatica 63/3geologia croatica 338 of 23.26%, 12.65% al. fe (48.03%), 11.44% mn, ca (1.54) and a mg content of 1.22%. the sem data for a garnet crystal picked from a calcrete sample shown in figs. 6f &7e suggests a si content of 39.22%, al (19.25%), fe (16.90%), mn (15.14%), ca (5.16%), and mg content of 1.73%. rutile is actually found in both analyzed samples and assumes different reddish brown and straw-yellow colours. rutile grains vary from highly rounded to sub angular in sha pe. according to deer et al. (1962), the colour differences in the rutile grains generally correspond to variation in their chemical composition. sem data confi rm the chemical composition of rutile (figs 4g& 6d) for the residual soil sample and the calcrete sample (figs. 6d and 7e). ilmenite crystals have only been detected in the calcrete sample, being completely absent in the residual soil sample. they occur as black metallic crystals characterized by their angular to irregular shape. the corresponding sem microphotograph (fig. 6e) and the edax spectra (fig. 7c) for a separated ilmenite mineral grain refl ect both the morphological features and the chemical composition of this mineral. 3.2.4. mica mica grains occur in minor amounts in the residual soil sample in the form of soft fl exible fl akes, varying in colour from dark brown to black (mainly phlogopite). the corresponding sem microphotograph (fig. 4h) and the edax spectra (fig. 5e) for the separated mica fl akes refl ect the morphological features and chemical composition. a bright yellow secondary uranium mineral was discovered interstitially between the mica fl akes (fig. 4h), semiquantitative analysis of which suggests that u attains up to 76.41% with an fe content of 14.15% and a si content of 2.77 (fig. 5f). 3.3. geochemical investigation the country rocks of the studied residual soil and calcrete are actually represented by the clastic and non clastic rocks of the upper member of the qatrani formation. these rocks are generally non-radioactive (mohamed, 1965) however; some uranium anomalies are associated with the carbonaceous shale where it forms a ridge or a cliff, whereas when this shale is interbedded within the succession, it only shows uranium background levels (haroun, 2001). according to mousa & haroun (2006), the uranium concentration of some carbonaceous shale sites ranges from 17 to 34 ppm while the average universal background of the carbonaceous shale is 3.5 ppm (turekian & wedepohl, 1961). radiometric analyses of the collected representative samples from the residual soil and calcrete deposits indicated that the uranium concentration in the former ranges from 20 to 200 ppm with an average of 94 ppm while it assays at 121 and 85 ppm in the two studied calcrete samples (table 1). these results indicate that both the residual soil and calcrete sediments assay a uranium content that is generally higher than that of the country rocks, and the fossil tree trunks, which are scattered within the studied residual soil in some sites. the trace elementscontent of the study rock facies was evaluated by xrf analysis, performed on 14 trace elements in some representative samples of the residual soil and calcrete. the results are summarized in table 2, in comparison with the data of turekian & wedepohl (1961) from shale. this comparison indicates quite clearly that the studied sediments are enriched in zr, y, zn, sr and v. however, it has been discovered that while sr in the residual soil is lower than turekian & wedepohl’s (1961) average, it is much higher than the latter in the calcrete samples. this is most probably due to the presence of the carbonate cement. the genesis of uranium and the analyzed trace elements in both the studied residual soil and calcrete facies is discussed below. 4. mineral genesis in their study of oligocene rocks surrounding the local depression and sub basin of the radioactive quaternary sediments, el kammar et al. (2000) reported that both the sandstones and the siltstones are the most common lithologies in the oligocene qatrani formation. the sandstone can be described as a quartz – arenite where the detrital quartz constitutes >90% of the framework material. the heavy mineral fraction of these sandstones and siltstones indicates that hematite and goethite are the main opaque constituents as they represent about 50% of the total heavy fraction. the detected non-opaque heavy minerals include zircon, rutile, epidote, tourmaline, garnet, kyanite, biotite, staurolite and amphiboles. field investigation revealed that both the clastic sandstone and siltstone facies of the oligocene qatrani formation are the main bed rocks and country rocks of the studied residual soil and calcrete deposits, and all the heavy detrital minerals separated from these deposits are actually derived by mechanical weathering of the country rocks. weathering was by the action of both wind and water currents where the resistant heavy minerals such as zircon, garnet, apatite and rutile were deposited in the local low lying area of the residual soil and calcrete. table 1: uranium content in residual soil (r.s.) and calcrete (c.) as quaternary sediment sample no. u (ppm) r.s.1 50 r.s.2 123 r.s.3 200 r.s.4 99 r.s.5 133 r.s.6 20 r.s.7 32 average 94 c.1 121 c.2 85 raslan and haroun: geology and mineralogy of the radioactive quaternary sediments of the north fayium depression, western desert, egypt geologia croatica 339 table 2: trace element content (ppm) of the studied residual soil (r.s) and calcrete (c) as quaternary sediments compared with shale of major unit of earth crust (t&w), after turekian & wedepohle, 1961. nb v ga sr pb ba y rb zr zn cu ni co cr sample no. 2 167 10 132 22 98 250 98 380 111 45 50 50 102 r.s.1 9 170 16 102 23 51 240 51 437 211 62 86 52 86 r.s.2 5 8 u.d 1381 34 261 u.d u.d 295 174 13 19 3 85 c.1 u.d 6 u.d 1192 42 236 u.d 5 266 259 21 42 3 74 c.2 25 400 12 600 180 140 90 50 80 20 100 t&w u.d. undetected figure 5: edx analysis for the studied minerals of residual soil a zircon; b apatite; c garnet; d rutile; e mica and f uranium mineral. geologia croatica 63/3geologia croatica 340 4.1. genetic aspects of uranium mineralization the possible mechanism of uranium accumulation in both the residual soil and the calcrete can be described according to the following sequence of operations; 1. the area of the residual soil is topographically considered as a local sub basin which has received all the detrital sediments and surfi cial fl uids that have been derived from the bed rocks forming the upper successive scarps. these different types of surfi cial fl uids involved both hydrothermal solutions that accompanied the tertiary volcanicity as well as ground and meteoric waters. 2. the fl uids leached uranium from the oligocene bones formed mainly of apatite and which were enriched in uranium (haroun, 2001), ranging from 113 up to 930 ppm with an average of 394 ppm. however, the th content in these bones is below the limit of detection (el kammar et al, 2000). 3. the leached uranium remained in a soluble form in the acid waters (mixed descending and ascending waters), probably as the complex uranyl ion, to be secondarily enriched in the porous sediments of the residual soil and calcrete via different adsorbents; namely, clays, organic matter, carbonate etc. figure 6: sem backscattered electron images for the studied heavy minerals separated from calcrete sample. a & b zircon crystals, c apatite, d ilmenite, e rutile, f garnet raslan and haroun: geology and mineralogy of the radioactive quaternary sediments of the north fayium depression, western desert, egypt geologia croatica 341 4.2. trace element distribution the relative enrichment of some trace elements can be determined by comparing the trace element content of both the residual soil and calcrete with their average values in the average crustal shale of turekian & wedepohl (1961), (table 2 and fig. 8). from this comparison, the following can be concluded; 1. the enrichment of zn and zr in the residual soil and calcrete may be attributed to the following: – according to el kammar and basta, (1983), zn is considered one of the elements enriched in the weathering zone. the highest enrichment factor is for zn. the authors believe that zn (0.74 aº in zn=6) which was substituting for fe (0.74 aº in zn =6) in pyrite was liberated during oxidation. – high iron content is present in both the basalt and the red bed forming the bed rock surrounding the local basin of the residual soil and calcrete. – the increased zr assay may be attributed to the presence of zircon in the residual soil as confi rmed by the sem analyses. 2. the enrichment of v in the residual soil as indicated by xrf analyses (table 2 and fig. 8) is mostly due to the weathering processes of the basaltic bed rock (abdel fi gu re 7: edx analysis for the separated minerals from calcrete sample. a zircon, b apatite, c ilmenite, d rutile, e garnet geologia croatica 63/3geologia croatica 342 magid et al., 1992), which contains a relatively high content of mafi c minerals. also, the increased v content may be due to the presence of iron minerals such as hematite, goethite and limonite, which represent the main opaque grains in the heavy mineral fraction of the sandstone bed rock (el kammar et al., 2000). 3. the enrichment of y in the residual soil may be attributed to the weathering of yrich vertebral bone embedded in the oligocene rocks. according to el kammar et al, (2000), y concentration in the vertebral bone can reach up to 583 ppm. these authors further mentioned that the accumulation of sr+y+ree in the rocks would follow in decreasing order from bone > shale > siltstone > sandstone > duricrust. 4. enrichment of sr in the calcrete deposits (table 2 and fig. 8) is most probably due to its liberation during diagenetic dolomitization of the calcite cement (el hashimy, 1976). such released sr would readily be accommodated together with the sulphate of the weathering zone (el kammar & basta, 1983). the high concentration of sr in the calcrete can also be attributed to its leaching from sr francolite and phosphate minerals (el agami et al., 2005) and/or its leaching from the petrifi ed oligocene bones randomly scattered upon the surface of the bench scarps of the study area. according to el kammar et al., (2000), the vertebrate bones could contain a high concentration of sr reaching up to 1940 ppm. 5. conclusion field relationships, sem and chemical analyses revealed the relative enrichments of uranium and some trace elements such as sr, zr and y in the studied residual soil and calcrete deposited on the eroded surface of oligocene rocks. mineralogical investigation of the studied sediments reveals the presence of zircon, apatite, ilmenite, rutile and garnet. additionally, a secondary uranium mineral was discovered interstitially between the mica fl akes. weathering, erosion and transportation processes led to the presence of zircon, apatite, ilmenite, rutile and garnet as persistent heavy accessory detrital minerals in the studied radioactive sediments. the u, sr, zr, y and v budget of these sediments are potentially interesting. references abdel-magid, a., mettwaly, a. & morsy, m. (1992): tecto nic evolution of continental basalt of egypt: geochemical evidences. – egyptian mineralogist, 4, 141–158. abu zeid, s. & abdel monem, a.a. (1957): the discovery of uranium bearing quartzitic veins at gebel qatrani area.– geology and raw material dept., aee, cairo, internal report. cameron, j. (1967): nuclear raw materials prospecting and evaluation.– technical assistance report to the government of the united arab republic rep., no. 362, iaea, vienna. carlisle, d. (1984): concentration of uranium and vanadium in calcretes and gypcrete.– in: wilson, r.c.l. (ed.): residual deposits: surface related weathering processes and materials. geol. soc. london, 185–195. deer, w.a., howie, r.a. & zussman, j. (1962): rock forming minerals, vol. 5., non silicates.– john wiley and sons, new york. el-agami, n.l. abdel wahab, a.a. & haroun, y.s. (2005): mineralogy, geochemistry and origin of aluminum phosphate-sulphate minerals in g. el hefhuf, bahriya oasis, western desert, egypt.– the fourth international conference on the geology of africa, 2, 289–292. el hashimy, w.s. (1976): signifi cance of sr distribution in some carbonaceous rocks in the carboniferous of north umberland.– egyptian j. sediment. petrol., 46/20, 369–376. el sayed, m.i., morsy, a.m. & haroun, y.s. (2000): field occurrence, petrography and possible origin of surfi cial uranium anomalies of the post oligocene deposits in fayium depression.– 5th intern. conference on the geology of arab world, cairo university, february 2000, 436–462. el shazly, e.m, el hazek, n., abdel monem, a., khawasik, s., zayed, z., mostafa, m. & morsy, m. (1974): origin of uranium in oligocene qatrani sediments, western desert, are.– proceeding of iaea, 467–478. el kamar, a.m. & basta, e.z. (1983): chemical weathering of the economic phosphate of abu tartor. w.d.– chemical geology, 38, 321–328. fi gu re 8: variation diagram of trace elements in the studied quaternary deposits. raslan and haroun: geology and mineralogy of the radioactive quaternary sediments of the north fayium depression, western desert, egypt geologia croatica 343 el kamar, m.m, el kamar, a.m. & el gamal, m.a. (2000): geochemistry of terrestrial tertiary bones from fayium, egypt.– 5th international conference on the geology of arab world, cairo university, february 2000, 213–238. haroun, y.s. (2001): favourable geologic environment for uranium concentration in some areas in the north western desert, egypt.– ph.d thesis, faculty of science, cairo university, cairo, 182 p. haroun, y.s. & raslan, m.f. (2007): geology and mineralogy of radioactive petrifi ed trees in fayium depression area, westrn desert, egypt.– second conference on the geology of the tethys, cairo university, march 2007, 637–646. heinrich, e.w.m. (1958): minerology and geology of radioactive raw materials. mcgraw hill book company, new york. mousa, m. & haroun, s.y. (2006): contribution to geochemical characteristics of carbonaceous shale, qatrani, egypt.– sedimentology of egypt, 14, 295–305. morsy, m.a. (1978): lithological, stratigraphical and structural controls of uranium mineralization of qatrani area, western desert.– m.sc. thesis, faculty of science, cairo university, cairo. mostafa, m.e.m. (1972): geological studies for uranium occurrences in qatrani area, western desert, a.r.e.– m.sc. thesis, faculty of science, cairo university. pejatovic, s. (1968): geological regularities in situation of coaly clay-bearing uranium manifestation at the gebel qatrani area, fayium district.– geological and raw material department, aee, internal report. pettijohn, f.j. (1975): sedimentry rock.– harpper&row, publishers, new york, 628 p. reineck, h.e. & singh, i.b. (1973): depositional sedimentary environment, springer, verlag, berlin, 439 p. turekian, k.k. & wedepohl, k.h. (1961): distribution of the in elements in some major units of the earth crust.– geol. soc. america. bull., 72, 172–192. manuscript received january 01, 2010 revised manuscript accepted july 19, 2010 available online november 11, 2010 palmer.indd 143 �ab stra ct determining the nature of water fl ow and contaminant dispersion in karst requires far more information than can be provided by simple dye traces. tracing can delineate drainage divides, fl ow directions, and fl ow velocities at various stages, but from water management purposes it is also important to determine such variables as groundwater storage, retention times, patterns of convergence and divergence, and response to wet-dry cycles in the soil. these are most signifi cant in the non-conduit portions of the karst aquifer, which supply most wells. dye tracing can be augmented by hydrograph analysis at various stages, tracing with tagged solid particles or microbes, evaluation of dissolved solids and chemical equilibria, and isotopic analysis. this paper concentrates on some of the uses of chemical equilibria and isotopes. stable isotopes (e.g. 18o and deuterium) and the various radium isotopes are among the most useful. ratios among the four radium isotopes (228ra and 224ra, with half-lives in years; and 223ra and 226ra with half-lives in days) are well suited to karst studies. these techniques are time-consuming and costly, so a full analysis of a karst aquifer is rarely feasible. instead, it is recommended that selective analyses be made of representative parts of the aquifer, and that they be applied as follows: (1) develop conceptual models based on fi eld observation, which allow one to anticipate a range of probable scenarios of contaminant transport and remediation. (2) if digital models are used, it is most effective to design simple generalized models in which the boundary conditions are clearly defi ned, and then to gain insight into real aquifers by noting the differences between the model and fi eld observations. (3) use fi eld techniques to become familiar with the local hydrology and then apply hydraulic and chemical principles to anticipating contaminant behaviour, rather than reacting only to emergencies. these approaches encourage the growth of interpretive skills based on the same scientifi c principles that govern the origin of caves and karst. keywords: hydrologic models, geochemistry, isotopes, contaminant tracking understanding the hydrology of karst � arthur n. palmer department of earth sciences, state university of new york, oneonta, ny 13820, usa; (palmeran@oneonta.edu) doi: 104154/gc.2010.11 geologia croatica 63/2 143–148 2 figs. zagreb 2010 geologia croaticageologia croatica 1. introduction maintaining a safe water supply is diffi cult in karst, where the physical setting and modes of water movement are complex. this paper addresses two issues: fi rst, to introduce the great variety of interpretive fi eld techniques that are available to the karst hydrologist; and second, to suggest a realistic strategy for applying the resulting information to karst. effective water management in karst requires several types of fi eld data: (1) delineation of drainage basins and drainage divides. this task is complicated by the overlap of catchment areas where perched vadose fl ow crosses phreatic divides, and by the shifting of divides with time as fl ow stage varies. (2) flow directions, velocities, and discharge in solution conduits and in the dispersed fl ow outside the conduits. (3) patterns of convergence and divergence of groundwater, and their role in chemical dispersion. (4) effective pore and fi ssure sizes and their interconnectivity. this informati on helps the anticipation of likely paths of pathogen migration. (5) volume and duration of water retained in storage betwe en infiltration events (e.g., capillary water, perched pools, etc.). geologia croatica 63/2geologia croatica 144 ence of dispersion of water into the aquifer. during a fl ood pulse, the infl ow at fi rst typically exceeds the outfl ow, indicating accumulation of storage in conduits, abandoned upper-level cave passages, and neighbouring fi ssures and pores. during the waning phase of a fl ood pulse, the outfl ow exceeds the infl ow as storage is released. a long tail with a roughly logarithmic rate of decrease suggests the release of water as laminar fl ow, after the main turbulent-fl ow pulse has passed (atkinson, 1977). the volume released is found by integrating the area under the hydrograph (volume = ∑qδt, where q = discharge and t = time. response to storm events will vary with antecedent precipitation – for example, after a prolonged dry period when the infi ltration capacity of soil and fi ll material in epikarst fi ssures is dominated by desiccation fi ssures, in comparison with a prolonged wet period when soils are moist and have expanded to fi ll available bedrock fi ssures. much of the water that reaches the phreatic zone during an infi ltration event is composed of capillary water that has been held in storage from prior events and displaced by the new water pulse (shown by pitty (1966)). 2.3. measuring travel times: quantitative tracer tests estimating the position of drainage divides with dye traces is a long-established technique. detection of fl ow divergence, crossovers, and shifting of divides with fl ow stage are also important outcomes. these complexities increase with structural deformation. dominantly convergent and well-defi ned drainage patterns are typical of undisturbed strata, as in the central u.s.a. (e.g. quinlan & ray, 1981). in areas of greater structural complexity, such as the dinaric chain (e.g., baučić, 1968), features including divergent fl ow paths, crossovers, and overlapping groundwater divides are far more likely. dye tracing is discussed in many other publications (e.g., käss, 1998). much information can be gained by repeating quantitative dye traces at a wide variety of discharges. dye concentrations at detection points are measured at short time intervals so the exact arrival times, peak dye concentrations, and mean travel times (to centres of mass) can be detected. mean breakthrough times to each monitoring point are plotted as a function of discharge. a logarithmic scale allows coverage of a broad range of values and emphasizes differences in the shape of the plots (palmer, 2007). conduits that are mostly water-fi lled will show linear plots with slopes of –1 (fig. 1). paths composed mainly of open channels, such as canyons, produce concave-upward curves: as discharge rises, water depth also increases, and the increase in wetted perimeter, (p, length of contact of water with solid surfaces in a cross section), can increase almost as fast as the cross-sectional area (a). flow velocity is a function of the ratio a/p, so velocity in a fl ooding vadose channel tends to increase more slowly than in a water-fi lled conduit. a combination of open channels and closed conduits will give linear plots at low discharge that change to concave-upward curves at high discharge. complex patterns, such as overfl ow and divergence, 2. analytical techniques the variables listed above can be investigated in many different ways. major categories of hydrologic fi eld data are outlined here, mainly to demonstrate their utility and how they relate to each other. most are time-consuming, and some are costly as well, so it is rarely feasible to apply them in suffi cient detail to truly understand the behaviour of a karst aquifer. however, by considering them, we are forced to think about how karst aquifers behave. for further information see also milanović, 1981; bonacci, 1987, and ford & williams, 2007. 2.1. measurement of hydraulic head and gradients the most direct way to measure local hydrologic conditions is to measure heads in water wells and to determine their spatial and temporal variation. contouring of static water levels can give a good approximation of drainage divides and fl ow patterns, if the data are abundant enough and the geology is relatively simple (e.g., quinlan & ray, 1989). natural variations in head with time, provide much information on proximity to turbulent-fl ow conduits, as well as fl ow convergence and divergence at different stages. rap id rise and fall of head in response to rainfall or snow-melt events facilitates the delineation of major fl ow routes, with turbulent-fl ow solution conduits having the most extreme rates of response. laminar-fl ow zones within the aquifer respond more slowly, with broad, long-term rises and declines in head. volume of groundwater storage and rates of release can be estimated. variations in head with time can demonstrate the dispersal of water during fl ood pulses. as in other aquifers, pumping tests in karst provide considerable information on fl ow patterns, effective hydraulic conductivity, and anisotropy. spatial variability tends to be much greater than in other aquifer types. flow directions and anisotropy can also be anticipated from the geologic setting. hydraulic gradient is a critical component in all fl ow equations, whether laminar or turbulent. discharge and velocity are directly proportional to gradient in laminar fl ow but are related more or less to the square root of the gradient in turbulent fl ow. 2.2. discharge measurements combining discharge measurements with head data provides insight into the structural nature of the aquifer. discharge at springs and in cave passages is proportional to catchment area. it is more useful in determining aquifer properties to measure variations in discharge with time, especially in response to storms and/or snowmelt. differing responses of springs to what appear to be similar storm events can usually be accounted for by evapotranspiration loss and antecedent soil-moisture conditions, both of which show a strong seasonal effect. where the hydrology is simple, as where ponors feed a single spring, the comparison of discharge in vs. discharge out is a simple method for assessing the prespalmer: understanding the hydrology of karst geologia croatica 145 tive enrichment in the soil by calcite precipitation. a variety of de-icers on highways (nacl, cacl2, etc.) can be tracked and used as a proxy for contaminant fl ow paths from accidental spills. 2.6. equilibrium chemistry the degree of saturation of dissolved minerals in wells, springs, and caves helps to determine the fl ow history of the water and the nature of the openings through which it has passed. drip-waters in caves can also provide estimates of pco2 in the overlying soil. samples of infi ltration water must be collected where it fi rst emerges from the rock or sediment matrix so there is no loss of dissolved gases. the ph is measured in situ, and precipitation of dissolved solids is prevented by hcl acidifi cation of one of a pair of samples. most seepage water is near saturation with calcite. saturation with dolomite generally requires lengthy residence time in an aquifer (typically years). signifi cant supersaturation with either mineral generally indicates loss of co2 from the water, e.g., by air exchange through open cave entrances or fi ssures. dripwater chemistry in caves, combined with discharge of the drips, can clarify the nature of vadose fl ow routes. is the water seeping slowly, with large areas of contact with fi ssure walls? is it following discrete solution channels? some of this information can be obtained from rate equations (e.g., plummer et al., 1978, dreybrodt, 1988). a generic rate equation for dissolution is dc/dt = (a’ k / v) (1 – c/cs)n (1) where dc/dt = change in concentration with time, k = reaction coeffi cient, n = reaction order, cs = saturation concentration (and therefore c/cs = degree of saturation, where 1.0 = saturation), a’ = surface area in contact with the water, and v = water volume. it is rarely possible to fi nd a unique solution to this equation, but the range of possibilities becomes clear. an integral solution, as well as values for n and k for typical karst situations, are given by palmer (1991). note that t/v is dimensionally equivalent to q, and a’ is proportional to fl ow length, so c/cs relates directly to discharge and to the network of openings through which the water has passed. a pco2 signifi cantly greater than that of the soil suggests a hypogenic co2 source. for example, at saratoga springs, new york, water is actively degassing as it emerges from the springs. the fl ow is discontinuous, with spurts and bubbles. with the assumption that the water at depth was at equilibrium with calcite, back-calculation indicates that its pco2 was more than 6 atmospheres. reaction-path software is useful in the calculations (seewww.usgs.gov/software). pco2 signifi cantly less than atmospheric is common but diffi cult to measure. seepage into carbonate rock through an insoluble cap-rock allows dissolution to take place under nearly closed conditions, because the reaction is isolated from the reservoir of soil co2. pco2 can drop to as little as 10–4 to 10–5 atm. this is diffi cult to measure, because local fl ow rates are very small, and co2 is absorbed rapidly from may complicate the analysis, but they can also be revealed by this method. approximate conduit size and water volume within it can also be crudely estimated. it is useful to know the approximate percentage of a conduit that is vadose. low-density contaminants that are mainly insoluble in water will tend to fl oat and accumulate at sumps. during fl ood pulses, much of a normally vadose conduit will fi ll with water and drive the contaminants upward into many narrow fi ssures. leakage of volatile gases to the surface has been documented (e.g., in bowling green, kentucky; crawford, 1984), where volatile gases have accumulated in buildings to near explosive limits. even if the entire interpretive procedure is not feasible, it is helpful merely to anticipate the fi eld conditions that lead to this problem. 2.4. use of tagged tracers the ability of pathogens to be carried by groundwater can be estimated by tracing with solid particles of discrete size. an ideal tracer consists of natural indigenous microbes that have been tagged with an identifi er that is incorporated into the living cells. brahana, (2009) describes this technique in a karst basin in arkansas that is isolated for hydrologic research. the bacteria are exposed to a europium solution and reintroduced into sinking streams and other infi ltration points. the tagged bacteria are transported, temporarily deposited, and re-suspended during fl ood pulses in the karst conduits. their movement through the system is monitored in caves, wells, and springs. such studies can determine the fl ow conditions in which they are most prevalent at the sampling points. use of local microbes gives a more realistic response in terms of transmission, retention, and delay than artifi cial particles. 2.5. analysis of dissolved solids measurement of dissolved solids at different fl ow stages can clarify fl ow paths where a variety of porous media are present. interpretations are fairly straightforward and are not elaborated here. for example, high values of sulphates and chlorides suggest deep fl ow components (most abundant during low fl ow); and mg/ca ratios >1.0 suggest evaporafi gu re 1: variation in tracer breakthrough time vs. discharge in (a) a 1000m-long conduit 1 m in diameter; (b) a vadose canyon 1 m wide and 1000 m long, with slope = 0.01 and manning friction factor = 0.05; and (c) a 500-mlong cayon as in b, leading to a 500-m-long tube as in a. geologia croatica 63/2geologia croatica 146 the cave air. results include rills, etching, and weathering of cave walls where seepage water suddenly becomes highly aggressive toward carbonates (palmer, 2007). discharge per unit area is low, but the total over large areas can be substantial. infi ltration through insoluble rock can be verifi ed, and contaminant paths and fi ltering can be anticipated. 2.7. stable-isotope chemistry flow rates and storage in non-conduit parts of a karst system can be assessed through the use of isotope chemistry. 18o and deuterium (2h) in precipitation vary seasonally, and when plotted on a graph of δ18o vs. δ2h they tend to fall on a straight line. this “local meteoric water line” is typically close to, and nearly parallel to, that of the global mean data, defi ned by δ2h = 10 + 8 [δ18o], as shown in fig. 2. during the cold season, the points plot at the lower left (more depleted in the heavier isotopes); and during the warm season they plot at the upper right. as this water infi ltrates and travels through the aquifer, it retains most of its initial isotopic signature. changes due to co2 uptake and dissolution of carbonates have little effect, because their total molar contribution to the water is only a tiny fraction. the discrepancy in isotopic signature between local precipitation and of a ground water sample increases with time for the fi rst half year, and then diminishes. this discrepancy forms a sinusoidal curve with time (fig. 3), and therefore the “age” (residence time) of the water since it fi rst precipitated can be estimated in most cases. a single measurement is not suffi cient; a time series needs to be developed that shows the seasonal variation over a long time (ideally several years). a groundwater sample that tracks almost exactly with that of the precipitation is likely to have spent less than a single season reaching its present point in the aquifer. large discrepancies indicate longer residence times in the ground. an erratic correlation requires more care in interpretation. comparison of values in a variety of places in the aquifer is likely to clarify the overall picture of residence times. groundwater that is supplied by a wide range of water sources, typical of bathyphreatic fl ow, tends to have a clustering of oxygen-deuterium values somewhat low on the meteoric water line, regardless of time of year (fig. 1). this is because most of the infi ltration takes place in the transition from cold to warm, when snow melt is high and evapotranspiration is low. points to the right of the local meteoric water line normally indicate evaporative enrichment of the heavy isotopes at the surface. (it may also indicate long-term inheritance from local bedrock, but this appears to be minor in karst aquifers.) for example, mcfail’s cave, new york receives many drips along its length of about 11 km. some of the land above it is swampy, so there is great opportunity for evaporation. some of the drips show a signifi cant shift to the right, away from the meteoric water line, and these are interpreted as being fed by wetlands. the position of the drips relative to the wetlands supports this idea, but there are local discrepancies that appear to indicate lateral movement of vadose water down the dip of the strata. sulphate content can be used as an indicator of depth of groundwater fl ow. for example, in the same fi eld area there are sulphate-rich springs that show a sulfur isotopic signature (δ34s) that is identical to that of the solid sulphates in a local silurian dolomite, which in this area lies at a depth of up to 100–200 m below the surface. this same water shows a clustering of oxygen-deuterium values that does not vary signifi cantly with time. the δ34s values plot exactly in the range of values for silurian marine sulphate rocks. 2.8. use of radioactive isotopes: the example of radium one of the most promising avenues for investigating karst hydrology is the interpretation of radium (ra) isotopes. little has been done in this fi eld, and certain details have yet to be understood. bedrock contains trace amounts of uranium and thorium: 238u, 235u, and 232th. decay of 238u produces 226ra (half-life of 1601 yr), and 235u produces 223ra (half-life of 11.1 days). 232th produces both 228ra (half-life of 5.7 yr) and 224ra (half-life of 3.54 days). all ra isotopes decay to radon (rn) and eventually to lead (pb). water in contact with bedrock or sediment acquires these isotopes by dissolution. the main governing variables are shown by equation 1. with four radium isotopes of varied sources and half-lives, they provide a potentially great amount of information about fl ow patterns in karst. for general reference, see kraemer & genereux, 1998. those with long half-lives (years) are 226ra and 228ra. those with short half-lives (days) are 223ra and 224ra. as water travels through narrow fi ssures or fi ne-grained material with large areas of contact and long residence times, it equilibrates with the local bedrock and sediment values. the ratio 235u/238u is about 0.0466, so that is the equilibrium ratio for the decay products 223ra/226ra. but 224ra and 228ra come from the same parent (232th), so 224ra/228ra ideally approaches 1.0. fi gu re 2: oxygen-deuterium graph in the eastern new york karst. a = early spring snowmelt; b = rapid cave drips, late spring; c = cave streams, late spring; d = rapid cave drips, late summer; e = springs fed by deep groundwater, year-round; f = springs fed by ponors, late spring; g = cave drips beneath 60 m of low-permeability cover, fall; h = surface lake, summer; j = cave drips beneath 20 m of high-permeability cover, fall; l (to right of meteoric water line) = cave drip fed by overlying swamp, fall; m = springs fed by ponors, fall; n = rainfall, summer. data from terrell et al. (2005), siemion (2006) and the author. palmer: understanding the hydrology of karst geologia croatica 147 high activities of the long-lived ra isotopes indicate lengthy and intimate contact with bedrock or sediment. high activities of the short-lived ra (224ra and 223ra) indicate recent release of water from pores and narrow fi ssures into larger bodies of water, where they decay faster than they can be replenished from the solids. zones of seepage into streams (at the surface or underground) can be identifi ed in this way. the time since the seepage has entered the main body of water can be estimated by the amount of disequilibrium. for example, with time, the 224ra/228ra ratio decreases. this decrease can be caused by simple mixing between the incoming seepage and the stream or lake water; but if the seepage input retains its identity as a plume without substantial mixing (as in lakes fed by springs), the ratio decreases along an exponential decay curve instead of linearly. marine rocks (e.g., carbonates) have a low th/u activity ratio (<0.1), so they produce low 228ra/226ra ratios in groundwater. siliciclastic rocks have a higher th/u ratio (about 1.0), so 228ra/226ra also approaches 1.0, but slowly, and most water will have completed its tour of the aquifer long before it reaches equilibrium. individual strata can have their own 228ra/226ra identity. for example, shaly carbonates tend to have a higher 228ra/226ra than more pure carbonates. laboratory analysis of rock samples can clarify the expected ratios. in the madison carbonate aquifer of south dakota, recharge through overlying siliciclastic beds can be distinguished from recharge directly into the aquifer by their contrast in 228ra and 226ra, even where there is no difference in oxygen-deuterium content (kraemer & genereux, 1998). water can also acquire ra isotopes by alpha recoil: release of an alpha particle from a radioactive nucleus causes the source particle to recoil up to several hundred nanometres. if the source is located near the surface of a solid, it can be ejected into the adjacent fl uid. alpha recoil has a signifi cant effect only where there is a very large surface area, as in suspended fi ne-grained sediment. high 228ra/226ra ratios can result: up to at least 6 in slow-moving groundwater. this suggests both considerable alpha-recoil and also long residence times (tens or hundreds of years; tom kraemer, reston, virginia, personal communication). residence time of groundwater is often estimated with tritium, radiocarbon methods, etc., but the utility of those produced by human activity (e.g., tritium from atmospheric testing of nuclear devices) is diminishing with time. 3. conclusions the interpretive techniques described above are all interrelated by several major concepts: the mass balance, fl uid mechanics, dissolution kinetics, and chemical equilibrium. they share the same physical laws, concepts, and variables as those that govern the origin of karst. all require a fundamental understanding of the local geological setting. by applying these and similar techniques, one can understand the origin and development of karst in addition to how it behaves hydrologically. these techniques require considerable time and expense, so they are feasible only for long-term academic or government-sponsored research projects. it is important to develop suitable strategies for contaminant remediation by anticipating problems, rather than by reacting after a spill or leakage has already taken place. today the most common approach to groundwater management is digital modelling, in which the goal is to predict outcomes on the basis of a few simple fi eld measurements. this is rarely successful. instead, it is more appropriate to design simple digital models that are not expected to be correct, but the output of which can easily be compared to fi eld observations. confronted with the differences between the ideal model and reality, we are forced to visualize the fi eld conditions that can account for those differences. another approach to digital modelling is to develop interactive models of specifi c aspects of karst that allow one to explore the effects of varied fi eld conditions (e.g., dreybrodt et al., 2005). these methods encourage professional growth, in contrast to the typical accumulation of digital outputs that involve only repetitive data types and thought processes. a recommended strategy is fi rst to use fi eld techniques such as those described in this paper to gain insight into the behaviour of karst aquifers, and only then to progress to aquifer modelling, whether it be conceptual, analytical, statistical, or digital. field information should ideally be held in a central repository, (e.g., in a government-sponsored or academic karst centre), rather than scattered widely in the literature or in personal fi les. hydrologic and chemical fi eld measurements give personal insight into the internal workings of karst – an important step in the training and advancement of karst scientists. acknowledgment many thanks to margaret palmer for fi eld and laboratory assistance, tom kraemer for interpretive insight into radium geochemistry and graduate students elias moskal, levia terrell and jason siemion for collaboration in the fi eld. references atkinson, t.c. (1977): diffuse fl ow and conduit fl ow in limestone terrain in the mendip hills, somerset (great britain).– journal of hydrology, 35, 93–110. baučić, i. (1968): subterranean connections in the hydrological drainage basin of the cetina river.– proceedings of 4th international congress of speleology, ljubljana, 271–277. bonacci, o. (1987): karst hydrology.– springer-verlag, berlin, 184 p. brahana, v. (2009) the savoy experimental watershed, arkansas: a long-term research site for karst hydrogeology.– in: palmer, a.n. & palmer, m.v. (eds.): caves and karst of the usa. national speleological society, huntsville, alabama, usa, 179 p. crawford, n.c. (1984): toxic and explosive fumes rising from carbonate aquifers: a hazard for residents of sinkhole plains.– in: beck, b.f. (ed.): sinkholes: their geology, engineering, and environmental impact. balkema, rotterdam, 297–304. dreybrodt, w. (1988): processes in karst systems: physics, chemistry, and geology.– springer-verlag, berlin, 288 p. geologia croatica 63/2geologia croatica 148 dreybrodt, w., gabrovšek, f. & romanov, d. (2005): processes of speleogenesis: a modeling approach: carstologia, ljubljana, zrc publishing, 376 p. + cd ford, d.c. & williams, p.w. (2007): karst hydrology and geomorphology.– wiley, chichester, uk, 601 p. käss, w. (1998): tracing technique in geohydrology.– balkema, rotter dam, 581 p. kraemer, t.f. & genereux, d.p. (1998): applications of uranium and thorium-series radionuclides in catchment hydrology studies.– in: kendall, c. & mcdonnell, j.j. (eds.): isotope tracers in catchment hydrology. elsevier, amsterdam, 679–722. milanović, p.t. (1981): karst hydrogeology.– water resources publications, littleton, colorado, 434 p. palmer, a.n. (1991): origin and morphology of limestone caves.– geological society of america bulletin, 105/1, 1–21. palmer, a.n. (2007): cave geology.– cave books, dayton, ohio, 454 p. pitty, a.f. (1966): an approach to the study of karst water.– university of hull, u.k., occasional papers in geography, 5, 70 p. plummer, l.n., wigley, t.m.l. & parkhurst, d.l. (1978): the kinetics of calcite dissolution in co2-water systems at 5–60°c and 0.0–1.0 atm co2.– american journal of science, 278, 179–216. quinlan, j.f. & ray, j.a. (1989): groundwater basins in the mammoth cave region, kentucky.– in: white, w.b. & white, e.l. (eds.): karst hydrdology: concepts from the mammoth cave region. van nostrand reinhold, new york, one-page map insert. siemion, j. (2006): use of isotopes, tracer tests, and dissolved solids to characterize a karst aquifer.– m.a. thesis, state university of new york, oneonta, ny, 49 p. terrell, l., palmer, a. & kraemer, t. (2008): isotopic and chemical analysis of sulfate-rich springs along the helderberg escarp ment of east-central new york state.– geological society of america, northeastern section, annual meeting, abstracts with programs, 37/1, 69. manuscript received january 04, 2010 revised manuscript accepted march 19, 2010 available online may 31, 2010 61velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... plates plates were organized according to biostratigraphic criteria: only taxa which represent the basis for biostratigraphic zonation are presented. these are the most important index species after which the biozones were named. the majority of taxa cited in this paper will not be presented in plates, although some of them are also index species. these forms will be published in another paper, together with some previously undocumented or unknown species from the karst dinarides. most of the presented forms were photographed from my collection archived in the croatian geological survey. the only exceptions are, as already mentioned, photomicrographs of murciella cuvillieri (collection of blanka cvetko tešović, university of zagreb, faculty of natural sciences) and photomicrographs of microspheric rhapydionina liburnica and fleuryana adriatica provided by katica drobne (palaeontological institute i. rakovac of the slovenian academy of sciences and arts, ljubljana, slovenia). vercorsella camposaurii (sartoni & crescenti, 1962) vercorsella laurentii (sartoni & crescenti, 1962) vercorsella scarsellai (de castro, 1963) vercorsella tenuis (velić & gušić, 1973) vercorsella wintereri arnaud-vanneau & sliter, 1995 vidalina hispanica schlumberger, 1900 vidalina radoicicae cherchi & schroeder, 1985 voloshinoides murgensis luperto sinni & masse, 1993 2. calcareous algae campbelliella striata (carozzi, 1954) clypeina besici pantić, 1965 clypeina jurassica favre, 1927 palaeodasycladus mediterraneus (pia, 1920) pseudoclypeina cirici radoičić, 1970 salpingoporella annulata carozzi, 1953 salpingoporella dinarica radoičić, 1959 salpingoporella turgida (radoičić, 1964) selliporella donzellii sartoni & crescenti, 1962 62 geologia croatica 60/1 plate i 1, 3–4 lamelliconus procerus (liebus), carnian; 1, 3: karlovac area, 4: komiža, island of vis, croatia. 2 lamelliconus procerus and aulotortus friedli (kristan-tollmann); karlovac area, croatia. 5 carnian biofacies with lamelliconus procerus and aulotortus friedli; karlovac area, croatia. 6–8 triasina hantkeni majzon, rhaetian; south velebit mt., croatia. 9–10 rhaetian biofacies with triasina hantkeni and aulotortus sinuosus weynschenk; south velebit mt., croatia. scale bars – 1–4, 6–8: 0.2 mm; 5, 9–10: 0.5 mm. 63velić plate i 64 geologia croatica 60/1 plate ii 1–4 mesoendothyra sp., sinemurian–early pliensbachian; 1–2, 4: central velebit mt., 3: gornje jelenje, croatia. 5–8 lituosepta recoarensis cati, late sinemurian–early pliensbachian; 5–6: central velebit mt., 7–8: gornje jelenje, croatia. 9–11 orbitopsella primaeva (henson), late sinemurian–early pliensbachian; megalosphaeric forms, 9–10: south velebit mt., 11: north velebit mt. scale bars – 0.2 mm. 65velić plate ii 66 geologia croatica 60/1 plate iii 1–4 orbitopsella primaeva (henson), late sinemurian–early pliensbachian; 1 – megalosphaeric and microsphaerc forms, 2–4 – microsphaeric forms; 1, 3–4: north velebit mt., 2: central velebit mt., croatia. 5–6 orbitopsella praecursor (gümbel), pliensbachian; megalosphaeric forms, 5: central velebit mt., 6: plitvice, croatia. scale bars – 0.2 mm. 67velić plate iii 68 geologia croatica 60/1 plate iv 1–4 orbitopsella praecursor (gümbel), pliensbachian; 1 – megalosphaeric form, 2–4 – microsphaeric forms; 1: plitvice, 2–4: central velebit mt., croatia. scale bars – 1: 0.2 mm, 2–3: 2 mm, 4: 3 mm. 69velić plate iv 70 geologia croatica 60/1 plate v 1–4 pseudocyclammina liassica hottinger, late pliensbachian, velika kapela mt., croatia. 5–8 mesoendothyra croatica gušić, aalenian–bajocian; 5 – south velebit mt., 6–7 – biokovo mt., 8 – dubrovnik area, croatia. 9–12 gutnicella cayeuxi (lucas), aalenian–early bajocian; 9–10 – megalosphaeric forms, 11–12 – microsphaeric forms: dubrovnik area, croatia. scale bars – 1–11: 0.2 mm, 12: 0.5 mm. 71velić plate v 72 geologia croatica 60/1 plate vi 1–6 timidonella sarda bassoullet, chabrier & fourcade, aalenian–early bajocian; 1–5 – megalosphaeric forms, 6 – microsphaeric form; 1: dubrovnik area, 2–5: biokovo mt., croatia, 6: suha krajina, slovenia. scale bars – 0.2 mm. 73velić plate vi 74 geologia croatica 60/1 plate vii 1–6 pseudodictyopsella jurassica septfontaine & de matos, early bajocian, biokovo mt., croatia. 7–12 marzoella ficcarellii chiocchini & mancinelli, early bajocian, biokovo mt., croatia. 13–16 paravalvulina complicata septfontaine, late bajocian, biokovo mt., croatia. scale bars – 0.2 mm. 75velić plate vii 76 geologia croatica 60/1 plate viii 1–5 paleopfenderina salernitana (sartoni & crescenti), bathonian; 1–3, 5 – microsphaeric forms, 4–5 – megalosphaeric forms; 1: south velebit mt., 2: north velebit mt., 3–5: biokovo mt., croatia 6–9 satorina apuliensis fuorcade & chorowicz, late bathonian, 6–7, 9: western istria, 8: south velebit mt., croatia. 10–12 kurnubia jurassica (henson), late callovian–oxfordian; 10, 12: western istria, 11: south velebit mt., croatia. scale bars – 0.2 mm. 77velić plate viii 78 geologia croatica 60/1 plate ix 1–2 kurnubia jurassica (henson), late callovian–oxfordian; 1: south velebit mt., 2: gornje jelenje, croatia. 3–5 kurnubia palastiniensis henson, oxfordian–kimmeridgian; 3–4: velika kapela mt., 5: biokovo mt., croatia. 6–8 kurnubia wellingsi (henson), late oxfordian–kimmeridgian; 6: south velebit mt., 7–8: velika kapela mt., croatia. 9–11 conicokurnubia orbitoliniformis septfontaine, kimmeridgian; 9: south velebit mt., 10–11: velika kapela mt., croatia. scale bars – 1–8, 10–11: 0.2 mm, 9: 0.5 mm. 79velić plate ix 80 geologia croatica 60/1 plate x 1–7 alveosepta jaccardi (schrodt), kimmeridgian, velika kapela mt., croatia. 8–13 parurgonina caelinensis cuvillier, foury & pignatti-morano, late kimmeridgian–early tithonian; 8: velika kapela mt., 9–10: dubrovnik area, 11–13: gornje jelenje, croatia. scale bars – 1–9, 11–13: 0.2 mm, 10: 0.5 mm. 81velić plate x 82 geologia croatica 60/1 plate xi 1–5 protopeneroplis ultragranulata (gorbatchik); 1–2, 4–5: tithonian, kupres, bosnia and herzegovina, 3: berriasian, dubrovnik area, croatia. 6–11 vercorsella camposaurii (sartoni & crescenti), valanginian, western istria, croatia. scale bars – 0.2 mm. 83velić plate xi 84 geologia croatica 60/1 plate xii 1–4 campanellula capuensis de castro, latest hauterivian–earliest barremian, western istria, croatia. 5–9 rectodictyoconus giganteus schroeder, late barremian; 5–8: banja luka area, bosnia and herzegovina, 9: jajce area, bosnia and herzegovina. 10–11 palorbitolina lenticularis (blumenbach), late barremian; 1: ogulin area, croatia, 2: jajce area, bosnia and herzegovina. scale bars – 1, 4–7, 9–11: 0.2 mm, 2–3: 0.1 mm, 8: 0.5 mm. 85velić plate xii 86 geologia croatica 60/1 plate xiii 1 palorbitolina lenticularis (blumenbach), late barremian, dinara mt., croatia. 2–6 palorbitolina lenticularis (blumenbach), early aptian; 2, 4–5: ogulin area, 3, 6: south velebit mt., croatia. 7–10 praeorbitolina cormyi schroeder, early aptian, ogulin area, croatia. 11 transitional form between praeorbitolina cormyi schroeder and praeorbitolina wienandsi schroeder, early aptian, ogulin area, croatia. 12 praeorbitolina wienandsi schroeder, early aptian, ogulin area, croatia. scale bars – 1–4, 6–12: 0.2 mm, 5: 0.1 mm. strasser & samankassou.indd 1. introduction knowledge about rates of sedimentation is of great importance for the understanding of sedimentary systems. sedimentation rates reflect the availability of sediment and the conditions in the area of accumulation. sedimentation rates also are important input parameters for computer modelling. sediment accumulation is controlled by supply (i.e. material transported into the system and/or produced in-situ) and accommodation (i.e. the space available carbonate sedimentation rates today and in the past: holocene of florida bay, bahamas, and bermuda vs. upper jurassic and lower cretaceous of the jura mountains (switzerland and france) andré strasser and elias samankassou to store this material – schlager, 1993). sediment supply rates may be highly variable, from rapid coralreef growth to pelagic fall-out controlled by seasonal plankton blooms, and to episodic deposition through storms or turbidity currents. rates of accommodation change are the combined rates of sea-level change and change in subsidence. in shallow water, supply may be higher than accommodation, and sediment is redistributed into other environments. it is therefore useful to speak of accumulation rate in a given position in the sedimentary basin. once the sediment is accumulated, it may be eroded and redistributed through changes in accommodation and/or current activity. the final stratigraphic record commonly represents only part of the sedimentation history, and it might therefore be adequate to distinguish also preservation rate. several authors (e.g., bosscher & schlager, 1993; plotnick, 1986; sadler, 1981, 1994; schlager, 1999) have argued that “accumulation” rates decrease with increasing time spans over which they are calculated. this relationship probably reflects the fact that more hiatuses are included with increasing time intervals (i.e. a diminished preservation potential) rather than changes in sediment availability. in this paper, we concentrate on sedimentation rates on shallow carbonate platforms where sediment is to a large extent produced by organisms. consequently, ecological control is important. siliciclastics and nutrients are introduced by continental run-off, which in turn is controlled by climate. by first evaluating sedimentation rates in holocene systems where the controlling parameters are relatively well known, we then estimate rates in ancient sedimentary environments. we have chosen upper jurassic and lower cretaceous sequences that contain facies comparable to those studied in the holocene and where high-resolution sequence stratigraphy and cyclostratigraphy furnish the adequate time frame. 2. holocene sedimentation rates a large amount of literature is available where holocene sedimentation rates in shallow-water carbonate systems are indicated (e.g., cloud, 1962; shinn et geologia croatica 56/1 1–18 14 figs. 2 tabs. zagreb 2003 key words: shallow-marine carbonates, sedimentation rate, sequence stratigraphy, cyclostratigraphy, holocene, upper jurassic, lower cretaceous, florida bay, bahamas, bermuda, jura mountains. department of geosciences, geology–palaeontology, university of fribourg, ch-1700 fribourg, switzerland; e-mail: andreas.strasser@unifr.ch abstract lagoonal to intertidal sediments from the holocene in florida bay, on the bahamas, and in bermuda are compared to similar facies in the kimmeridgian and berriasian of the swiss and french jura mountains. dating by 14c permits the estimation of sediment accumulation rates in the holocene. in the ancient outcrops, the timing is given by cyclostratigraphic analysis. elementary depositional sequences formed in tune with the 20-ka precession cycle, although much of this time may have been spent in non-deposition and/or erosion. after decompaction of the ancient sequences, their accumulation rates can be evaluated. it is suggested that the studied holocene sediments accumulated over the past 6000 years with rates of 0.3 to 3 mm/a, whereas the kimmeridgian and berriasian facies show somewhat lower rates of 0.07 to 0.6 mm/a. this difference may be due to methodological errors, but also to variable carbonate production. in shallow carbonate systems, much of the sediment produced may be redistributed over the platform or exported. furthermore, basin morphology and currents can strongly influence facies and thickness of the accumulated sediment. finally, the accumulated sediment may suffer further erosion before it is preserved in the sedimentary record. consequently, when estimating sedimentation rates in ancient sequences, it is important to do this with the highest time resolution possible, and only after having decompacted the sediment and evaluated the time lost in hiatuses or condensed intervals. 3strasser & samankassou: carbonate sedimentation rates today and in the past...2 geologia croatica 56/1 tidal flats and in lagoons accumulates relatively slowly. ooid, peloid, or bioclastic shoals accumulate within a relatively small range of 0.5–2 mm/a. in order to also evaluate lateral changes in facies and accumulation rates, shallow cores have been taken in florida bay, on the bahamas, and in bermuda. we have chosen sites that are mostly protected from high energy and constant reworking, and where relatively continuous sediment accumulation can be expected. a plastic tube was pushed or hammered into the soft sediment, sealed, and then pulled back. the sediment core was extracted with a pushing device, and the total compaction induced by these processes was measured. it is assumed that this compaction partly reflects the mechanical compaction the sediment would undergo through burial. in fact, the calculated compaction corresponds well to the values obtained experimentally by shinn & robbin (1983) from similar facies. the cores were described and sampled. samples were impregnated with epoxy, and thin sections were made. mangrove peat, bivalve shells, or corals were taken for 14c analyses. sample preparation and dating was performed by the radiocarbon laboratory of the institute of physics at the university of berne, switzerland. the results are listed in table 1. the ages are conventional (calculated by using the libby half-life value) and expressed in years before present (1950). al., 1965; stockman et al., 1967; kukal, 1971, 1990; smith, 1971; chave et al., 1972; thomson & turekian, 1973; enos, 1974, 1991; moore, 1972; sarnthein, 1973; turmel & swanson, 1976; gebelein, 1977; hallock, 1981; bosence et al., 1985; wanless & tagett, 1989; kennedy & woodroffe, 2000; heap et al., 2001; mackinnon & jones, 2001; calhoun et al., 2002; yang et al., 2002; gischler, 2003). in fig. 1, 352 data points assembled from the references cited above have been grouped to represent different depositional environments. coral framework reefs are the fastest sediment producers, whereas sediment on fig. 1 compilation of 352 sedimentation rates according to the literature cited in the text. table 1 dated samples and estimated sediment accumulation rates for the holocene cores. for interpretation see text. 3strasser & samankassou: carbonate sedimentation rates today and in the past... is encountered. this same facies dominates in core 5, where roots of sea-grass are also common. mangrove peat in cores 3 and 4 implies that the shoreline was positioned farther to the north than today. it is interesting to note that the mangrove peat below the pond (in cores 1 and 2) is younger but topographically lower than the peat in the shoreface core (3). this suggests that a shallow mangrove pond existed behind a beach barrier already 1000 years ago. above the peat in cores 1 to 4, yellowish mud with very little fauna predominates, indicating a restricted environment. bird’s eye structures occur in cores 1 and 2 and indicate the intertidal zone. ravinement surfaces appear in cores 3 and 4, which are overlain by sand composed of peloids, bivalves, gastropods, and foraminifera. layers of this sand are found in the pond behind the beach ridge and imply washover processes. microbial mats finally seal the cores in the pond. on cotton key, three cores represent a mud bank, and one core a small bay suffering erosion (fig. 3). the dominant facies in all cores is carbonate mud with 2.1. florida bay the holocene lagoonal sediments and mudmounds in florida bay are well described by, e.g., enos & perkins (1979), wanless & tagett (1989), and bosence (1989a, b, 1995). sedimentation started when post-glacial sea-level rise induced flooding of the subaerially exposed pleistocene limestones and created accommodation space. the florida keys protect the bay from high energy, and mostly muddy, biodetrital carbonates accumulate. mud banks aggrade and prograde. islands form, which are colonised by mangroves and locally contain freshwater lakes. windward (i.e. northern to eastern) margins of the islands are commonly eroded, whereas on the leeward sides mud accumulates in elongated banks (enos & perkins, 1979). on crane key, five cores have been taken along a transect from a pond on the island, over a beach ridge, to the shallow lagoon (fig. 2). below the peat in cores 1 and 2, a lagoonal facies of grey carbonate mud with peloids, benthic foraminifera, bivalves, and gastropods 3strasser & samankassou: carbonate sedimentation rates today and in the past... fig. 2 shallow sediment cores on crane key, florida bay (to the north of windley key). 5strasser & samankassou: carbonate sedimentation rates today and in the past...4 geologia croatica 56/1 peloids, benthic foraminifera, bivalves, gastropods, ostracodes, and fragments of the green alga halimeda. layers with concentrations of broken shells indicate periodic reworking by high energy. a porites coral fragment points to storm transport through a channel from the southern side of the florida keys, where coral carpets occur (bosence et al., 1985). on the top of core 4, the sediment is winnowed to produce peloidal– bioclastic carbonate sand. pigeon key has furnished two cores (fig. 4). one is situated on the erosive eastern side of the island and displays two phases of mangrove growth. carbonate sand is winnowed on the sediment surface and preserved in crab burrows. the second core represents the mud bank. peloids, bivalves, gastropods, benthic foraminifera, ostracodes, and organic fragments float in a muddy matrix. little crawl key is situated on the southern side of the florida keys (fig. 5). energy generally is higher than in florida bay, and a sandy beach has developed. coral fragments (porites) at the base of the cores indicate fully marine conditions. winnowed peloidal sands with gastropods, bivalves, halimeda, red algae, and benthic foraminifera dominate the facies. muddy sediment with bioturbation occurs in the middle part of the cores. fig. 4 shallow sediment cores on pigeon key, florida bay (north of tavernier on key largo). fig. 3 shallow sediment cores on cotton key, florida bay (to the northwest of windley key). 5strasser & samankassou: carbonate sedimentation rates today and in the past... 5strasser & samankassou: carbonate sedimentation rates today and in the past... 2.2. bahamas we have taken cores in two low-energy settings from the bahamas: on andros island, and on lee stocking island. the holocene sedimentation of the andros tidal flats has been described in great detail by hardie (1977). in the three creeks area on andros island, a core taken on the levee of a tidal channel reveals mudclasts in its lower part (fig. 6). this suggests lateral migration of the levee facies over the channel floor where such clasts had accumulated. the core taken in the pond shows a relatively homogeneous facies of carbonate mud with peloids, benthic foraminifera, bivalves, and gastropods. the gastropods (cerithids) are concentrated locally but are in-situ. on lee stocking island (exuma cays), an isolated pond has been cored (fig. 7). the mangrove peat in the lower part of core 1 accumulated over a period of about 1000 years. it is followed by sandy facies containing peloids, bivalves, cerithid gastropods, benthic foraminifera, and ostracodes. the upper part of the core is muddy but still contains cerithids. in core 2, which now is closer to the border of the pond, marine facies including echinoids directly overlie the pleistocene substrate. in its upper muddy part, foraminifera still testify to a marine influence. it is concluded that this pond has evolved from a bay, and that it was closed by a beach barrier only very recently. fig. 5 shallow sediment cores on little crawl key (south of us highway no. 1, west of crawl key). fig. 6 shallow sediment cores on the southernmost tidal channel in the three creeks area, northwestern andros island, bahamas. 7strasser & samankassou: carbonate sedimentation rates today and in the past...6 geologia croatica 56/1 however, if the facies in a core is more or less homogeneous and no erosion or reworking occurred, it can be assumed that the values shown in table 1 are representative. accumulation rates for the studied low-energy, lagoonal, and peat sediments vary between 0.3 and 3.0 mm/a. these values are comparable to the ones compiled in fig. 1. the sandy facies in tucker’s town bay accumulated with an average of 0.5 mm/a. deposition of muddy sediment was precluded by tidal currents. on little crawl key, coral rubble at the base of the cores and beach sands at the top imply some winnowing. nevertheless, because the sandy sediment in tucker’s town bay and on little crawl key filled in the available accommodation space and no erosion surfaces are visible, the estimated sedimentation rates can be considered as accumulation rates. low values appear where there is evidence for erosion (on crane and pigeon keys) or for a lag deposit (in great sound, bermuda). these rates therefore do not express sediment production and accumulation but rather the potential for preservation. 3. high-resolution sequence stratigraphy and cyclostratigraphy if sediment accumulation is controlled by sea-level fluctuations, the concepts of sequence stratigraphy can be applied to describe and interpret the resulting sedimentary sequences. although sequence stratigraphy classically deals with large sequences lasting a few hundred–thousand to a few million years (“third2.3. bermuda two sites have been studied on bermuda: the lagoon on ireland island south and tucker’s town bay on the southern side of castle harbour. the lagoon is connected to the ocean by two narrow inlets on either side (fig. 8). five cores have been taken, which show periodic high-energy influence in a generally low-energy system. facies are marine, including peloids, bivalves, gastropods, benthic foraminifera, and abundant halimeda plates. some bioclasts are blackened, indicating locally anoxic conditions (strasser, 1984). roots occur in all cores, and pieces of wood are locally concentrated in layers. lithoclasts indicate some reworking. the activity of the washover bar (cores 2 to 4) might have been somewhat influenced by the construction of the road along great sound. the relatively high age of the material dated at the base of core 5 in great sound indicates storm reworking close to the pleistocene substrate. in tucker’s town bay, peloidal–bioclastic carbonate sands including the red foraminifera homotrema rubrum fill the southern branch of the bay (fig. 9). the cores start with fine sands, which become coarser towards the top. 2.4. holocene accumulation rates because only few samples are suitable for 14c dating, accumulation rates can only be calculated as averages over a few thousand years. additional errors come from facies-dependent differential compaction (e.g., carbonate mud versus peat), which has not been corrected for. fig. 7 shallow sediment cores in a pond on the northwestern tip of lee stocking island, exumas, bahamas. 7strasser & samankassou: carbonate sedimentation rates today and in the past... 7strasser & samankassou: carbonate sedimentation rates today and in the past... order” sequences of vail, 1987; vail et al., 1991), its terminology can also be applied to deposits forming in much shorter time intervals (e.g., mitchum & van wagoner, 1991; posamentier et al., 1992; strasser et al., 1999). according to neumann (1971), digerfeldt & hendry (1987), and boardman et al. (1989), sea level in the caribbean and bermuda rose rapidly from its last glacial lowstand until about 5000 years bp and then slowed down to reach its present position. this curve represents the rising limb of a sea-level cycle controlled by insolation changes coupled to the orbital precession cycle of 20 ka (berger et al., 1989). consequently, the holocene sediments on shallow carbonate platforms are the record of only part of a sea-level cycle (fig. 10). in the pleistocene, when sea level was mainly controlled by slowly waxing and rapidly waning ice caps, the sea-level curve especially of the 100-ka eccentricity cycles was highly asymmetric (e.g., shackleton, 1987). in past greenhouse worlds, ice in high latitudes probably was present (frakes et al., 1992; eyles, 1993; valdes et al., 1995), but ice-volumes were not sufficient to induce important glacio-eustatic fluctuations. however, volume changes of alpine glaciers could make a small contribution (fairbridge, 1976; fig. 8 shallow sediment cores in the lagoon (ireland island south, western bermuda). fig. 9 shallow sediment cores in tucker’s town bay, eastern bermuda. 9strasser & samankassou: carbonate sedimentation rates today and in the past...8 geologia croatica 56/1 surface (fig. 10). the resulting sedimentary record thus shows first a deepening, then a shallowing trend of facies evolution. in the sequence-stratigraphic terminology, the initial flooding corresponds to the transgressive surface, the relatively deepest facies to the maximum flooding, and the erosion surface to the sequence boundary. the sediment cores illustrated in figs. 2 to 9 would thus correspond to the late highstand deposits, covering the last few thousand years of sedimentation history. an exception is core 5 of the lagoon in bermuda (fig. 8), where the shell debris dated at about 5600 years bp may represent a storm-influenced transgressive lag. locally, the sediment has filled the available accommodation space and even built up low islands, while in other places the sediment surface still is subtidal. currentand wave-induced erosion is active in the case of the mounds in florida bay, but cementation and karstification due to sea-level fall has not yet occurred. global warming is even causing sea level to rise again (ipcc, 2001), thus counteracting the fall that would be expected according to the orbitally induced reduction in insolation (berger, 1978). valdes et al., 1995). sea-level changes were also created by thermal expansion and retraction of the uppermost layer of ocean water (gornitz et al., 1982), by thermally-induced volume changes in deep-water circulation (schulz & schäfer-neth, 1998), and/or by water retention and release in lakes and aquifers (jacobs & sahagian, 1993). consequently, sealevel cycles during greenhouse conditions were of low amplitude and probably relatively symmetrical (read et al., 1995). on shallow carbonate platforms, initial flooding of a subaerially exposed surface results in a lag deposit. sediment production starts up once the carbonateproducing organisms have colonised the newly available space. if the ecological conditions are suitable, carbonate production will soon outpace sea-level rise (neumann & macintyre, 1985) and fill in the available space. slowing-down of sea-level rise will further accelerate this process, and sea-level drop will lead to erosion and reworking of the previously deposited sediment. if a fresh-water lens develops, carbonate cementation sets in within a few hundred years (e.g., halley & harris, 1979) and stabilises the sediment. karstification may further lower the sediment fig. 10 trend of holocene sea-level rise and comparison with a hypothetical, symmetrical sea-level cycle related to the 20-ka orbital precession cycle. for discussion see text. 9strasser & samankassou: carbonate sedimentation rates today and in the past... 9strasser & samankassou: carbonate sedimentation rates today and in the past... tude, high-frequency sea-level changes. the biostratigraphic and chronostratigraphic framework, as well as the stacking pattern of these sequences, suggest that the sea-level fluctuations were controlled by orbitally induced insolation changes. detailed descriptions and interpretations of the purbeckian sections are given in strasser (1988) and strasser & hillgärtner (1998). the high-resolution sequence stratigraphy and cyclostratigraphy of the kimmeridgian in the swiss jura have been studied in detail by colombié (2002). as in the purbeckian, facies indicate shallow-lagoonal to peritidal depositional environments. in the sequences shown in figs. 11 and 12, lagoonal packstones to wackestone with normal-marine fauna dominate. lithoclasts and black pebbles occur at the base of some sequences, indicating that the top of the previous sequence had been subaerially exposed and cemented before the transgression reworked these elements. the tops of the sequences commonly display bird’s eyes and dolomitization implying intertidal to supratidal conditions. erosion surfaces occur at the top of some sequences. clay seams or thin marly layers separate the beds. a comparison of holocene and kimmeridgian facies is shown in fig. 13. the peloidal–bioclastic muds of the holocene cores compare well with the lagoonal wackestones of the kimmeridgian and berriasian. in the ancient rocks, of course, diagenesis is more advanced and has led to the local development of dolomite crystals and to the filling of pore space with calcite cement. 4.2. decompaction before sedimentation rates in the ancient rocks can be estimated and compared to their holocene counterparts, the depositional sequences have to be decompacted. mechanical reorganisation of grains and dewatering in carbonate mud leads to a porosity loss of 10 to 30% after the first 100 m of burial (moore, 1989). the experiments of shinn & robbin (1983) yielded values of 20 to 70% of volume loss through mostly mechanical and dewatering compaction. these values are lower if carbonate cementation sets in very early (e.g., halley & harris, 1979). with deeper burial, chemical compaction becomes important. pressure solution at grain contacts testifies to some dissolution processes in the studied sediments. their burial depth is not known but probably never exceeded 2 km (trümpy, 1980). goldhammer (1997) proposes a compaction of slightly over 50% for 1 m of carbonate mud buried at 1000 m, and of about 15% for 1 m of carbonate sand at the same burial depth. according to enos (1991), muddy terrigenous and muddy carbonate sediments do not have significantly different compaction curves. however, pressure solution along clay seems may of course enhance chemical compaction in carbonates (e.g., bathurst, 1987). based on these published values, the following decompaction factors have been in the ancient sedimentary record, depositional sequences commonly are hierarchically stacked (e.g., goldhammer et al., 1993; montañez & osleger, 1993; d’argenio et al., 1997). strasser et al. (1999) proposed a descriptive classification of elementary, small-scale, medium-scale, and large-scale sequences. an elementary sequence is the smallest detectable unit where facies changes indicate one cycle of environmental change (including accommodation change). for the estimation of sedimentation rates, it is mandatory to analyse the smallest units that can be distinguished, i.e. the elementary sequences, which also correspond to the shortest time span. by detailed analysis of facies and surfaces, short-term changes in accumulation rate and hiatuses may be detected, and a more realistic picture of the sedimentary history is obtained than by averaging over thick sequences and long time spans. the error margins for dating ancient sedimentary rocks are large and can reach values on the millionyear scale (berggren et al., 1995). however, a relatively high time resolution can potentially be reached by cyclostratigraphy. the periodicities of the orbital cycles (milankovitch cycles) are known (e.g., schwarzacher, 1993). although the motions within the solar system are chaotic and the predictability of the orbits of the inner planets (including earth) is lost within a few tens of millions of years (laskar, 1989), the periodicities can also be estimated for older geological times (berger et al., 1989). if it can be shown that the sedimentary record was controlled by orbitally induced environmental changes (including sea-level changes), then a relatively high time resolution can be reached (potentially 20 ka). through the sequence-stratigraphic interpretation, this time interval can be further subdivided (fig. 10). the exact durations of the transgressive and highstand intervals, the transgressive lag time, and the time spent in erosion and non-deposition are, of course, speculative. 4. ancient sedimentation rates in order to compare holocene and ancient sedimentation rates, depositional sequences with facies similar to those described above have been chosen in upper jurassic and lower cretaceous sections in the swiss and french jura mountains. the jura realm at those times was a large, structurally complex, subtropical carbonate platform at the northern margin of the tethys ocean (ziegler, 1988; dercourt et al., 2000). 4.1. facies and sequences the lower berriasian (purbeckian) is characterised by shallow-lagoonal, intertidal, and supratidal carbonate facies (carozzi, 1948; häfeli, 1966; strasser, 1988). the facies evolution through time allows the identification of depositional sequences, the formation of which was significantly influenced by low-ampli11strasser & samankassou: carbonate sedimentation rates today and in the past...10 geologia croatica 56/1 4.3. estimation of time and accumulation rates in fig. 11, three individual elementary sequences from the lower berriasian are presented. they are interpreted to have formed in tune with earth’s precession cycle of 20 ka (strasser, 1988; strasser & chosen for the present study: 1.2 for grainstones and 2.5 for mudstones. for packstones and wackestones, the intermediate factors 1.5 and 2 are assumed, for marls the factor 3. these values are, of course, only rough estimates but nevertheless allow for an approximation of the original sediment thickness. fig. 11 selected 20-ka sequences in lower berriasian and lower kimmeridgian sections of the swiss and french jura. for discussion see text. ~ = ~ ~ "" '00 ~ ~ "'" .~ '00 = ~ ,~ "" ,~ '00 ~ , " lower berriasian (jura mountains) col de l'epine lower kimmeridgian (jura mountains) , (notdecompaaed) reuchenelte '" 17.18 a ' _ , e<asian , 17.17 '».li»~ lagoonal mudstones " 17.16 ._--tidal flat 17.15 "'"= ;>' ;t~;t dolomitizod tagoonal . __ '-: .~ -17.14 wackestones =.'" · -<o>~ ~ 11.13 " . lagoonal n>jdstones '" . to wackestones "'= 17.12 ty. -'" · "' -------17.11 · -. '" "'" lagoonal wackestones \7,10 = 179 i~~ , (sequences are decompacted) saltwe peloidal packstone with onooids 2q ka y doiomitized tidal flat (decompacted) '" 1£. -, ~ -s8 i. = '" " 20'" ~ , '" ' = ! -/·,1'"r -. ,, '" ;:>0 ka = '" y i. = "'" 100 ka '" 20 ka ",,, = , '" . ,,= ? '" ----i. -.,,= 1 20 '" . "'''' = " a y ~~ t 20ka t:£ a a , , 17,8 -----------_. s8 doiomitized tidal flat sah~ve j "''' ? -,..,.. tidal ~al i. ~ ~ ~ ~ -._. @ '" .... lagoonal , 20 ka , pad<stone· wackestone " @ '" .. ~ .. . :~ . 53·97 ~ " , ~~i tidal ~al legend peloids '" onooids • ooids a li!hodasls -black pebbles flat pebbles = e<:hinoderms '" foraminifera bivalves @ gastropods , ostracodes " green algae • charophyles " bioturbation ~ bird's eyes """ microbial lamination m dolomitization sb sequence boundary (loo i<a) 11strasser & samankassou: carbonate sedimentation rates today and in the past... 11strasser & samankassou: carbonate sedimentation rates today and in the past... (colombié, 2002). the lowermost 20-ka sequence is thin and shows reworking at its base and intertidal conditions at its top. the following sequences are thicker and display only subtidal facies. marly seams separating the beds are probably related to sea-level falls that mobilized clays in the hinterland but did not cause emersion at the site where the observed sediments were deposited. at the level of sample re-17.12, high accommodation precluded distinct features that mark a boundary between sequences. from lateral correlation it is implied that two 20-ka sequences compose the interval from sample re-17.10 to 17.13, but it is not clear which one of the two joints (above and below re-17.12) corresponds to the boundary. in sample re-17.15, subtidal hillgärtner, 1998). the sequence from the col de l’epine outcrop in the french jura presents a lag deposit at its base and erosion features at its top. the tops of the two salève sequences display bird’s eyes, and one is dolomitized. in accordance with the model of fig. 10 it is therefore suggested that only part of the 20 ka was actually spent in sediment accumulation. an estimate of 6000 years is used for the calculation of sedimentation rates (table 2). the part of the kimmeridgian reuchenette section shown in fig. 11 illustrates the stacking of 20-ka sequences into a 100-ka sequence, the latter reflecting the first eccentricity cycle of the earth’s orbit fig. 12 the two thickest 20-ka sequences encountered in the studied lower kimmeridgian and lower berriasian sections, respectively. in the salève section, only four 20-ka sequences can be interpreted within the 100-ka sequence. there may have been condensation at either one of the 100-ka sequence boundaries, or the 100-ka cycle terminates with the tidal flat below sample sa-38. 13strasser & samankassou: carbonate sedimentation rates today and in the past...12 geologia croatica 56/1 fig. 13 comparison of holocene and lower kimmeridgian facies. the bar in a is 0.5 mm long and valid for all photomicrographs. a–d holocene material (fractures are due to sample preparation): a – peloidal wackestone. the biotic components are benthic foraminifera (arrow) and bivalves (sample flo-5). b – wackestone. ostracodes (arrow), benthic foraminifera, shell fragments, and rare peloids occur (sample flo-16). c – wackestone–packstone. peloids are the main components, along with benthic foraminifera (sample bah-1). d – wackestone–packstone. peloids, ostrocodes (arrow) and benthic foraminifera (above the letter d) are the recognisable components (sample bah-4). e–h fossil material: e – wackestone. components include peloids and miliolid foraminifera (arrow) (sample re-17.11). f – wackestone. peloids are the main components, along with ostracodes (arrow) (sample re-17.14). g – slightly dolomitized wackestone including miliolids, pseudocyclammina (arrow), and broken bivalve shells (sample re-17.15). h – wackestone with charophytes (c), peloids, coated intraclasts (arrow), and bivalves (sample re-17.18). 13strasser & samankassou: carbonate sedimentation rates today and in the past... 13strasser & samankassou: carbonate sedimentation rates today and in the past... these changes depend not only on sediment supply and accommodation, but also on local factors such as the pre-existing morphology of the sea floor that may influence the carbonate-producing organisms, and currents that redistribute the sediment. with holocene sea-level rise flooding the platform, the sediments first record a deepening trend related to this transgression. however, with a decrease in the rate of sea-level rise, and sediment filling in the available space, a shallowing-upward facies evolution and progradation set in. in south-western florida, the turn-around from retrogradation to progradation has been dated at about 3500 years bp (parkinson, 1989). on the isolated platforms in belize, yang et al. (2002) have shown that carbonate sediments accumulate slowly during early transgression (0.2–0.5 mm/a), faster during the late transgressive and early highstand phases (1.1–1.7 mm/a), and fastest during highstand conditions (2.4–4.6 mm/a). the theoretical effects of basin morphology are shown in fig. 14. if sea level does not drop below the platform edge, lowstand deposits develop in depressions on the platform, while the highs are exposed to erosion, cementation, and karstification. in basins isolated from the open ocean, fresh-water lakes can form. rising sealevel then leads to initial flooding of the exposed land and to reworking of lowstand material. morphological barriers serve as thresholds, and isolated basins may be flooded instantly when this threshold is passed. this will lead to abrupt facies changes that, however, need not be synchronous all over the platform. a synfacies is overprinted with dolomite. this indicates a lowering of sea level and conditions close to emersion. the following 20-ka sequence displays bird’s eyes at its bottom and top. it is terminated by an erosion surface that is intepreted to represent a 100-ka sequence boundary (colombié, 2002). for the estimation of the corresponding sedimentation rates, it has been assumed that accumulation time of the 20-ka sequences with erosion or emersion features was 6000 years, whereas the full 20,000 years were allowed for the sequences that do not show signs of emersion or erosion (table 2). in addition, the thickest sequences of the reuchenette outcrop (colombié, 2002) and of the salève outcrop (strasser & hillgärtner, 1998) have been chosen to estimate sedimentation rates when accommodation was at its maximum (fig. 12). the average accumulation rates for the studied sequences vary between 0.07 and 0.6 mm/a (table 2). this is lower than in the holocene examples. however, it has to be considered that large uncertainties are inherent in the estimation of decompaction factors and accumulation time. 5. discussion and conclusions in holocene shallow carbonate systems, it is seen that sediment accumulation rates vary laterally as well as through time (e.g., bosence et al., 1985; calhoun et al., 2002; yang et al., 2002; gischler, 2003). table 2 estimated sediment accumulation rates for lower kimmeridgian and lower berriasian sequences. for interpretation see text. 14 geologia croatica 56/1 15strasser & samankassou: carbonate sedimentation rates today and in the past... chronous transgressive surface will only form once all islands are flooded. the final transgressive deposits will be relatively homogeneous all over the platform. during maximum flooding, condensation may set in if the water is too deep for efficient carbonate production. on the other hand, accommodation is increasing, and the thickest sediment package per time unit can potentially accumulate. with the lowering of sea-level, accommodation will be rapidly filled in, and the highstand deposits are forced to prograde. further sea-level drop then exposes the sediment surface, and a sequence boundary forms. the consequence is that, during the same sealevel cycle, time available for sediment accumulation may vary dramatically from one place on the platform to the other. there is no reason to believe that ancient platforms were less complex than modern ones, even if the high-frequency sea-level changes affecting them were of lower amplitude. to demonstrate this complexity, however, very high time resolution and lateral correlation of sections are needed. for example, strasser et al. (in print) interpret a step-wise flooding of the jura platform in the berriasian: each 20-ka sea-level pulse pushed ooid bars farther into the platform interior. samankassou et al. (in print) show lateral facies variations within an oxfordian 20-ka sequence over a few metres only: coral framestones are juxtaposed to ooid grainstones, and a tidal-flat facies is coeval with the top of a reef. in the holocene, the amount of carbonate produced on a shallow, tropical platform generally exceeds the amount of sediment accumulated on the platform top, and much of it is exported to the slope and the basin (droxler & schlager, 1985; milliman et al., 1993; schlager et al., 1994). also in the oxfordian of the swiss and swabian jura there is evidence that carbonate was exported from the platform to the basin (pittet et al., 2000). the rate at which sediment is fig. 14 hypothetical space–time diagram illustrating the different durations of sediment accumulation depending on platform morphology. as a result of erosion, reworking, and condensation, sediment thicknesses may vary considerably through time and space. 14 geologia croatica 56/1 15strasser & samankassou: carbonate sedimentation rates today and in the past... produced (or supplied) thus does not correspond to the rate at which it accumulates in a given locality. the holocene sediments have accumulated on the platform tops over a relatively short time span. sea level has not yet dropped, and most of the sediment that accumulated is also preserved (although it may be pushed back and forth on migrating islands and sand bodies). in the ancient sequences, however, erosion surfaces and vadose caps commonly indicate sea-level drops below the sediment surface, and part of the originally accumulated sediment may be missing. if longterm (million-year scale) accommodation gain was low or negative, the measured sediment thickness will of course not correspond at all to the accumulation potential of an individual sea-level cycle. consequently, it would be erroneous to conclude on the health of a shallow-water carbonate system based only on the sediment that is preserved. in florida, on the bahamas, and in bermuda, accommodation gain over the last 6000 years was about 5 m (fig. 10), and most holocene sediment accumulated within this time span. the studied kimmeridgian and berriasian elementary sequences are, when decompacted, commonly a few metres thick (and may reach 7 or 11 metres; table 2). accommodation gain thus seems to be comparable between the holocene and the ancient settings. for comparable lagoonal–peritidal facies, the holocene sediment accumulation rates appear to be somewhat higher (0.3–3 mm/a; table 1) than the ancient ones (0.07–0.6 mm/a; table 2). however, the kimmeridgian and berriasian values are still higher than the ones published for similar ancient environments (0.03–0.09 mm/a; wilson, 1975; schlager, 1981; enos, 1991). the differences between holocene and ancient accumulation rates as estimated in this study may be due to methodological errors, but can also imply that carbonate production on the jura platform was lower during kimmeridgian and berriasian times. the reasons for this may be differences in water temperature and water chemistry, the generally higher clay input, and/or evolutionary changes in the carbonate-producing organisms. if production rates are assumed to have been similar to those in the holocene, the lower net accumulation rates on the ancient platforms may result from increased carbonate mud export towards the basin (pittet et al., 2000). although our study is punctational and only compares a few selected holocene sequences with a few ancient ones, the following conclusions can be drawn: – it is useful to distinguish between supply (or production) rates, accumulation rates, and preservation rates. depending on the purpose of the study, the appropriate rate has to be estimated. – sediment accumulation rates must be estimated over a time span as short as possible in order to avoid averaging that also includes hiatuses or condensation. – considering the complexity of shallow-water carbonate platforms, it is dangerous to use values that average over large distances and across facies belts. – there is a relatively good correspondence of estimated sediment accumulation rates between similar facies in the holocene and kimmeridgian or berriasian carbonate systems. the somewhat lower rates for the ancient sediments may be due to methodological errors, to differences in the ecology of the carbonateproducing organisms, and/or to differences in sediment redistribution. acknowledgements we thank claude colombié, christophe dupraz, georges gorin, wolfgang hug, jean-bruno pasquier and niels rameil for help with the field work. the 14c dates were measured by the radiocarbon laboratory of the institute of physics at the university of berne, switzerland, and we thank h.h. loosli, s. reese, and t. stocker for their help. the pertinent, constructive remarks of two anonymous reviewers were very helpful and improved the manuscript. igor vlahović is thanked for his careful editing. we gratefully acknowledge the financial support of the swiss national science foundation (projects 2046625.96 and 20-56491.99). 6. references bathurst, r.g.c. (1987): diagenetically enhanced bedding in argillaceous platform limestones: stratified cementation and selective compaction.– sedimentology, 34, 749–778. berger, a.l. (1978): long-term variations of caloric insolation resulting from the earth’s orbital elements.– quat. res., 9, 139–167. berger, a., loutre, m.f. & dehant, v. (1989): astronomical frequencies for pre-quaternary palaeoclimate studies.– terra nova, 1, 474–479. berggren, w.a., kent, d.v., aubry m.p. & hardenbol j. (eds.) (1995): geochronology, time scales and global stratigraphic correlation.– soc. econ. paleont. mineral., spec. publ., 54, 386 p., tulsa. boardman, m., neumann, a.c. & rasmussen, k.a. (1989): holocene sea level in the bahamas.– in: mylroie, j.e. (ed.): proc. fourth symposium on the geology of the bahamas, bahamian fieldstation, fort lauderdale, 45–52. bosence, d. (1989a): biogenic carbonate production in florida bay.– bull. marine sci., 44, 419–433. bosence, d. (1989b): surface sublittoral sediments of florida bay.– bull. marine sci., 44, 434–453. bosence, d.w.j. (1995): anatomy of a recent biodetrital mud-mound, florida bay, usa.– int. ass. sedimentol., spec. publ., 23, 475–493. 16 geologia croatica 56/1 17strasser & samankassou: carbonate sedimentation rates today and in the past... bosence, d.w.j., rowlands, r.j. & quine, m.l. (1985): sedimentology and budget of a recent carbonate mound, florida keys.– sedimentology, 32, 317–343. bosscher, h. & schlager, w. (1993): accumulation rates of carbonate platforms.– j. geol., 101, 345–355. calhoun, r.s., fletcher, c.h. & harney, j.n. (2002): a budget of marine and terrigenous sediments, hanalei bay, kauai, hawaiian islands.– sed. geol., 150, 61–87. carozzi, a. (1948): etude stratigraphique et micrographique du purbeckien du jura suisse.– kündig, genève, 175 p. chave, k.e., smith, s.v. & roy, k.j. (1972): carbonate production by coral reefs.– marine geol., 12, 123–140. cloud, p.e.jr. (1962): environment of calcium carbonate deposition west of andros island, bahamas.– u.s. geol. survey prof. paper, 350, 138 p. colombié, c. (2002): sédimentologie, stratigraphie séquentielle et cyclostratigraphie du kimméridgien du jura suisse et du bassin vocontien (france): relations plateforme – bassin et facteurs déterminants.– geofocus, 4, 198 p., fribourg. d’argenio, b., ferreri, v., amodio, s. & pelosi, n. (1997): hierarchy of high-frequency orbital cycles in cretaceous carbonate platform strata.– sed. geol., 113, 169–193. dercourt, j., gaetani, m., vrielynck, b., barrier, e., biju-duval, b., brunet, m.f., cadet, j.p., crasquin, s. & sandulescu, m. (eds.) (2000): atlas peri-tethys – palaeogeographical maps.– commisson of the geological map of the world, paris. digerfeldt, g. & hendry, m.d. (1987): an 8000 year holocene sea-level record from jamaica: implications for interpretation of caribbean reef and coastal history.– coral reefs, 5, 165–169. droxler, a.w & schlager, w. (1985): glacial versus interglacial sedimentation rates and turbidite frequency in the bahamas.– geology, 13, 799–802. enos, p. (1974): surface sediment facies map of the florida– bahamas plateau.– geol. soc. amer., map series, 4. enos, p. (1991): sedimentary parameters for computer modeling.– in: franseen, e.k., watney, w.l., kendall, c.g.st.c. & ross, w. (eds): sedimentary modeling, computer simulations and methods for improved parameter definition. kansas geol. survey bull., 233, 63–99. enos, p. & perkins, r.d. (1979): evolution of florida bay from island stratigraphy.– geol. soc. amer., bull., 90, 59–83. eyles, n. (1993): earth’s glacial record and its tectonic setting.– earth-sci. rev., 35, 1–248. fairbridge, r.w. (1976): convergence of evidence on climatic change and ice ages.– ann. n.y. acad. sci., 91, 542–579. frakes, l.a., francis, j.e. & syktus, j.i. (1992): climate modes of the phanerozoic.– cambridge univ. press, 274 p. gebelein, c.d. (1977): dynamics of recent carbonate sedimentation and ecology, cape sable, florida.– int. sed. petrogr. series, 16, 120 p., leiden. gischler, e. (2003): holocene lagoonal development in the isolated carbonate platforms off belize.– sed. geol., 159, 113–132. goldhammer, r.k. (1997): compaction and decompaction algorithms for sedimentary carbonates.– j. sed. petrol., 67, 26–35. goldhammer, r.k., lehmann, p.j. & dunn, p.a.. (1993): the origin of high-frequency platform carbonate cycles and third-order sequences (lower ordovician el paso gp, west texas): constraints from outcrop data and stratigraphic modeling.– j. sed. petrol., 63, 318–359. gornitz, v., lebedeff, s. & hansen, j. (1982): global sea-level trend in the past century.– science 215, 1611–1614. häfeli, c. (1966): die jura/kreide-grenzschichten im bielerseegebiet (kt. bern).– eclogae geol. helvetiae, 59, 565–696. halley, r.b. & harris, p.m. (1979): fresh-water cementation of a 1,000-year-old oolite.– j. sed. petrol., 49, 969–988. hallock, p. (1981): production of carbonate sediments by selected large benthic foraminifera on two pacific coral reefs.– j. sed. petrol., 51, 467–474. hardie, l.a. (ed.) (1977): sedimentation on the modern carbonate tidal flats of northwestern andros island, bahamas.– johns hopkins press, baltimore, 202 p. heap, a.d., dickens, g.r. & stewart, l.k. (2001): late holocene sediment in nara inlet, central great barrier reef platform, australia: sediment accumulation on the middle shelf of a tropical mixed clastic/carbonate system.– marine geol., 176, 39–54. ipcc (2001): climate change 2001: the scientific basis.– intergovernmental panel on climate change, cambridge univ. press, cambridge, 881 p. jacobs, d.k. & sahagian, d.l. (1993): climate-induced fluctuations in sea level during non-glacial times.– nature, 361, 710–712. kennedy, d.m. & woodroffe, c.d. (2000): holocene lagoonal sedimentation at the latitudinal limits of reef growth, lord howe island, tasman sea.– marine geol., 169, 287–304. kukal, z. (1971): geology of recent sediments.– academic press, london, 490 p. kukal, z. (1990): the rate of geological processes.– earthsci. rev., 28, 1–258. laskar, j. (1989): a numerical experiment on the chaotic behaviour of the solar system.– nature, 338, 237–238. mackinnon, l. & jones, b. (2001): sedimentological evolution of north sound, grand cayman – a freshwater to marine carbonate succession driven by holocene sealevel rise.– j. sed. petrol., 71, 568–580. milliman, j.d., freile, d., steinen, r.p. & wilber, r.j. (1993): great bahama bank aragonite muds: mostly 16 geologia croatica 56/1 17strasser & samankassou: carbonate sedimentation rates today and in the past... inorganically precipitated, mostly exported.– j. sed. petrol., 63, 589–595. mitchum, r.m.jr. & van wagoner, j.c. (1991): high-frequency sequences and their stacking patterns: sequence-stratigraphic evidence of high-frequency eustatic cycles.– sed. geol., 70, 131–160. montañez, i.p. & osleger, d.a. (1993): parasequence stacking patterns, third-order accommodation events, and sequence stratigraphy of middle to upper cambrian platform carbonates, bonanza king formation, southern great basin.– in: loucks, r.g. & sarg, j.f.. (eds): carbonate sequence stratigraphy. amer. assoc. petrol. geol., mem., 57, 305–326. moore, c.h. (1989): carbonate diagenesis and porosity.– developments in sedimentology, 46, 338 p. moore, h.b. (1972): an estimate of carbonate production by macrobenthos in some tropical soft bottom communities.– marine biol., 17, 145–148. neumann, a.c. (1971): quaternary sea-level data from bermuda.– quaternaria, 14, 41–43. neumann, a.c. & macintyre, i.g. (1985): reef response to sea level rise: keep-up, catch-up or give-up.– proc. 5th int. coral reef congress, tahiti, 3, 105–110. parkinson, r.w. (1989): decelerating holocene sea-level rise and its influence on southwest florida coastal evolution: a transgressive/regressive stratigraphy.– j. sed. petrol., 59, 960–972. pittet, b., strasser, a. & mattioli, e. (2000): depositional sequences in deep-shelf environments: a response to sea-level changes and shallow-platform carbonate productivity (oxfordian, germany and spain).– j. sed. res., 70, 392–407. plotnick, r.e. (1986): a fractal model for the distribution of stratigraphic hiatuses.– j. geol., 94, 885–890. posamentier, h.w., allen, g.p. & james, d.p. (1992): high resolution sequence stratigraphy: the east coulee delta, alberta.– j. sed. petrol., 62, 310–317. read, j.f., kerans, c., weber, l.j., sarg, j.f. & wright, f.m. (1995): milankovitch sea-level changes, cycles, and reservoirs on carbonate platforms in greenhouse and icehouse worlds.– soc. sed. geol., short course, 35. sadler, p.m. (1981): sediment accumulation rates and the completeness of stratigraphic sections.– j. geol., 89, 569–584. sadler, p.m. (1994): the expected duration of upwardshallowing peritidal carbonate cycles and their terminal hiatuses.– geol. soc. amer., bull., 106, 791–802. samankassou, e., strasser, a., di gioia, e., rauber, g. & dupraz, c. (in print): high-resolution record of lateral facies variations on a shallow carbonate platform (upper oxfordian, swiss jura mountains).– eclogae geol. helvetiae. sarnthein, m. (1973): quantitative daten über benthische karbonatsedimentation in mittleren breiten.– veröffentlichungen univ. innsbruck, 86, 267–269. schlager, w. (1981): the paradox of drowned reefs and carbonate platforms.– geol. soc. amer., bull., 92, 197–211. schlager, w. (1993): accommodation and supply – a dual control on stratigraphic sequences.– sed. geol., 86, 111–136. schlager, w. (1999): scaling of sedimentation rates and drowning of reefs and carbonate platforms.– geology, 27, 183–186. schlager, w., reijmer, j.j.g. & droxler, a. (1994): highstand shedding of carbonate platforms.– j. sed. res., b64, 270–281. schulz, m. & schäfer-neth, c. (1998): translating milankovitch climate forcing into eustatic fluctuations via thermal deep water expansion: a conceptual link.– terra nova, 9, 228–231. schwarzacher, w. (1993): cyclostratigraphy and the milankovitch theory.– developments in sedimentology, 52, 225 p. shackleton, n.j. (1987): oxygen isotopes, ice volume and sea level.– quat. sci. rev., 6, 183–190. shinn, e.a. & robbin, d.m. (1983): mechanical and chemical compaction in fine-grained shallow-water limestones.– j. sed. petrol., 53, 595–618. shinn, e.a., ginsburg, r.n. & lloyd, r.m. (1965): recent supratidal dolomite from andros island, bahamas.– in: pray, l.c. & murray, r.c. (eds.): dolomitization and limestone diagenesis. soc. econ. paleont. mineral., spec. publ., 13, 112–123. smith, s.v. (1971): budget of calcium carbonate, southern california continental borderland.– j. sed. petrol., 41, 798–808. stockman, k.w., ginsburg r.n. & shinn, e.a. (1967): the production of lime mud by algae in south florida.– j. sed. petrol., 37, 633–648. strasser, a. (1984): black-pebble occurrence and genesis in holocene carbonate sediments (florida keys, bahamas, and tunisia).– j. sed. petrol., 54, 1097–1109. strasser, a. (1988): shallowing-upward sequences in purbeckian peritidal carbonates (lowermost cretaceous, swiss and french jura mountains).– sedimentology, 35, 369–383. strasser, a. & hillgärtner, h. (1998): high-frequency sea-level fluctuations recorded on a shallow carbonate platform (berriasian and lower valanginian of mount salève, french jura).– eclogae geol. helvetiae, 91, 375–390. strasser, a., hillgärtner, h. & pasquier, j.-b. (in print): cyclostratigraphic timing of sedimentary processes: an example from the berriasian of the swiss and french jura mountains.– soc. sed. geol. (sepm), spec. publ. strasser, a., pittet, b., hillgärtner, h. & pasquier, j.-b. (1999): depositional sequences in shallow carbonate-dominated sedimentary systems: concepts for a high-resolution analysis.– sed. geol., 128, 201–221. 18 geologia croatica 56/1 thomson, j. & turekian, k.k. (1973): sediment accumulation rates in long island sound by pb-210 dating and an estimate of ra-228 flux (abstract).– eos trans., 54, 337. trümpy, r. (1980): geology of switzerland, a guide-book. part a: an outline of the geology of switzerland.– wepf & co. publishers, basel, 104 p. turmel, r.j. & swanson, r.g. (1976): the development of rodriguez bank, a holocene mudbank in the florida reef tract.– j. sed. petrol., 46, 497–518. vail, p.r. (1987): seismic stratigraphy interpretation procedure.– in: bally, a.w. (ed.): atlas of seismic stratigraphy i. amer. assoc. petrol. geol. stud. in geology, 27, 1–10. vail, p.r., audemard, f., bowman, s.a., eisner, p.n. & perez-cruz, c. (1991): the stratigraphic signatures of tectonics, eustasy and sedimentology – an overview.– in: einsele, g., ricken, w. & seilacher, a. (eds): cycles and events in stratigraphy. springerverlag, berlin, 617–659. valdes, p.j., sellwood, b.w. & price, g.d. (1995): modelling late jurassic milankovitch climate variations.– in: house, m.r. & gale, a.s. (eds): orbital forcing timescales and cyclostratigraphy. geol. soc., spec. publ., 85, 115–132. wanless, h.r. & tagett, m.g. (1989): origin, growth and evolution of carbonate mudbanks in florida bay.– bull. marine science, 44, 454–489. wilson, j.l. (1975): carbonate facies in geologic history.– springer-verlag, berlin, 471 p. yang, w., mazzullo, s.j. & teal, c.s. (2002): lateral and vertical variations in sedimentation rates of holocene subtidal platform carbonate sediments, belize.– abstract, gsa annual meeting, denver, 2002. ziegler, p.a. (1988): evolution of the arctic – north atlantic and the western tethys.– amer. ass. petrol. geol., mem., 43, 198 p. manuscript received february 5, 2003. revised manuscript accepted june 20, 2003. tucker.indd 1. introduction in the geological record one tends to think of formations composed of either limestones or sandstones, but rarely both. in fact, there are many cases of interbedded clastics and carbonates in repeated cyclic arrangements. such units occur on the small-scale (metre-thick cycles or parasequences, 4th/5th order), and on the larger-scale (10’s metre-thick, 4th order high-frequency sequences and 100’s metre-thick, 3rd order sequences). mixed lithologies, namely sandy limestones and calcarenaceous sandstones are relatively rare rocks, or at least they are rarely described and classified properly. terrigenous input is dominantly a function of clastic availability and relative sea-level change, with the rate of change of major significance (see mount, 1984 mixed clastic–carbonate cycles and sequences: quaternary of egypt and carboniferous of england maurice e. tucker and papers in doyle & roberts, 1988). mixedlithology cycles and sequences are perhaps more typical of icehouse periods. at these times of higher amplitude sea-level falls, terrigenous debris is supplied in abundance to shelves and basins, and with subsequent sealevel rises and flooding of coastal plains, carbonates are deposited extensively. thus, mixed carbonate–clastic sequences are more common in permo–carboniferous and quaternary successions, although they do occur in other periods too. in this personal review, clastic–carbonate interaction is briefly considered on two levels: a) mixed clastic– carbonate sediments and their penecontemporaneous deposition and b) interbedded clastic–carbonate cyclic sediments on the parasequence (metre-thick) and sequence (10’s–100’s metre-thick) scale. two case studies are then presented to illustrate the general principles, from the quaternary of the red sea coast in egypt, and the mid-carboniferous of northern england. 2. major controls on clastic and carbonate deposition the supply of clastic sediment to a sedimentary basin is largely controlled by the relief and erosion of the hinterland and the climate. on a large-scale, relief is created by geotectonics which determine uplift rates and topography. the generation of terrigenous debris itself is determined by the rock-types exposed, their break-upability, and the climate again, which controls the degree of weathering and the type and frequency of sediment transport by ice, wind and water. with regard to climate, a more humid regime leads to persistent mud-rich systems through more intense chemical weathering, the development of soils and presence of vegetation; a more arid climate leads to erratic sand/gravel-rich systems, through a more physical type of weathering and less influence from soils and vegetation. a medium-scale control is sea-level change, which affects position of base-level and gradients, and so sediment supply to the shoreline. falling sea-level leads to river entrenchment and downcutting, resulting in more clastic input to the basin; rising sea-level on the other hand, causes deposition in higher reaches of a fluvial system and so less sediment reaching the basin. geologia croatica 56/1 19–37 9 figs. 4 pls. zagreb 2003 key words: clastic–carbonate interaction, sequences, cycles, quaternary red sea, egypt, yoredale cycles, carboniferous cycles, england. department of earth sciences, university of durham, dh1 3le, england; e-mail: m.e.tucker@durham.ac.uk abstract there are various types of mixed clastic–carbonate sequences and parasequences in the geological record and sea-level change is one of the major controls on their development, as well as the obvious availability of terrigenous material. mixed-lithology sequences are especially well-developed in icehouse times, as in the permo–carboniferous and quaternary. the two major types, lower carbonate – upper clastic and lower clastic – upper carbonate sequences, reflect the rates of sea-level change and the source of clastic sediment – whether it is brought across the carbonate platform from the adjacent landmass or supplied axially to the basin. two examples of carbonate–clastic high-frequency sequences are discussed: 1) from the red sea coast of egypt, quaternary transgressive/highstand shallow-water carbonates and late highstand/falling-stage/lowstand clastics deposited in incised-valley fills and fan deltas, and 2) from northern england, mid-carboniferous ‘yoredale’ cycles of transgressive shelf carbonates passing up into highstand coarsening-up deltaic and shoreline clastics, capped by palaeosoils and coal. locally, falling-stage incised-valleys supplied sediments to the adjoining basin. one significant difference between these two examples is the palaeoclimate: arid in the red sea leading to the episodic supply of sand and gravel, and humid in the carboniferous resulting in the more continuous supply of mud and sand, each having a different effect on carbonate deposition. 20 geologia croatica 56/1 21tucker: mixed clastic–carbonate cycles and sequences... like clastic deposition, carbonate deposition is controlled by many factors, of which latitude, climate, environment (notably the absence of clastics, plus salinity, temperature, nutrient supply, depth and turbulence), sea-level change and tectonics, are the most important. these parameters are often inter-linked of course. the highest levels of productivity occur in the shallow, warm waters of the tropics, especially along high-energy platform margins. 3. effects of terrigenous sediment on carbonate-secreting organisms terrigenous material generally has a detrimental effect on carbonate production, affecting the carbonatesecreting organisms in several ways. turbidity brought about by fine-grained material in suspension affects organisms by reducing light penetration, causing animals and plants to live at shallower depths, and bunging up their feeding mechanisms. sudden influxes of mud and sand can smother and bury organisms, and high nutrient levels often accompany terrigenous input and lead to flourishing microbial activity. this has a deleterious effect on many higher organisms which are often oligotrophic. there are various responses of carbonate organisms to terrigenous input. some organisms have adapted to move quickly or extricate themselves from under a cover of sand or simply to fling the sediment off their growing surface. skeletons may be adapted to keep above a mobile sandy substrate, as in finger corals. others have adapted to soft muddy substrates by having flatter shells, as some bivalves and brachiopods. animals have also adapted to lower light levels, as in certain corals, by developing a more leafy or platy shape to increase their surface area. some organisms are adapted to low salinities, which often result from freshwater influx associated with terrigenous material. 4. contemporaneous clastic–carbonate deposition there are a good number of locations around the world where clastics and carbonates are being deposited in close proximity. 4.1. delta-front reefs there are many places where corals and coralline algae are able to tolerate the presence of terrigenous mud and this can lead to the development of local patch reefs. one recently described modern example is the mahakam delta, indonesia, where patch reefs dominated by platy corals are growing on the seawardmargins of abandoned mouth bars, surrounded by terrigenous mud (wilson & lockier, 2002). the reefs are forming in very shallow-water (<10 m) since light penetration is reduced by turbidity from the terrigenous mud. patch-reef growth in a deltaic setting can affect the delta development itself by redirecting turbid flows and bottom currents. tertiary examples of reefs in a deltaic setting also occur in the subsurface of indonesia and in spain, where they grew on fan deltas in the pyrenean foreland basin (santiseban & taberner, 1988) and granada basin (braga et al., 1990). 4.2. patch-reefs and carbonate sands on clastic shelves coral patch reefs growing on clastic shelves are well developed off eastern australia in the inner-shelf area of the great barrier reef (larcombe et al., 2001). here the shelf is mostly covered by relict alluvial sediment from earlier sea-level lowstands and reefs grow in areas of coarser, more stable, sands and gravels. wide expanses of carbonate sand, mostly of calcareous algal origin, occur on the shelf off ne brazil, where quartzrich sands were deposited at times of glacially-lowered sea-level (testa & bosence, 1998). mixing is now taking place in many areas through the strong current and wave activity. carbonate sands dominated by bivalve, barnacle and serpulid debris occur extensively along the western seaboard of britain, especially on the west shetland shelf, where there is now an absence of clastic influx (light & wilson, 1998). in both the brazilian and british shelf cases, the carbonates have formed since the post-glacial (flandrian) transgression. in fact in any area of clastic sediment starvation, carbonate sediments are likely to accumulate. the well-known white beaches of the inner and outer hebrides with ‘coral’ sands of comminuted coralline red algae are a case in point, and these occur all the way up to finnmark, northern norway. 5. mixed-lithology parasequences and sequences mixed-lithology metre-scale cycles (parasequences) and the much thicker mixed-lithology sequences and high-frequency sequences come in two broad types. in some cases the clastics, generally coarse grained, occur above the carbonates at the top of the parasequence/ sequence (lower carbonate – upper sandstone cycles), whereas in others, the clastics, usually mudrocks, occur in the lower part of the units, beneath the carbonates (lower mudrock – upper carbonate cycles). these mixed-lithology cycles are developed where carbonate platforms are attached to terrigenous source areas or where there is an axial supply of clastic material to the basin. the clastic input is mostly controlled by sealevel and base-level changes, less commonly through fault-related uplift. 20 geologia croatica 56/1 21tucker: mixed clastic–carbonate cycles and sequences... 5.1. lower mudrock – upper carbonate cycles in metre-scale (4th/5th order) carbonate cycles (parasequences) with lower mudrock beds, the clays are usually deeper-water marine or lagoonal facies, derived from reworking of muddy coastal plains and supplied by rivers. the upper carbonates are oolitic-bioclastic grainstones or peritidal fenestral microbial lime mudstones. overall, the parasequences themselves are generally shallowing-upward cycles generated by progradation of tidal flats or the shoreface–foreshore over the deeper-water muds. many of these mudrock– limestone parasequences were subtidal cycles, not subject to subaerial exposure. the depth of deposition of the mudrocks would have been a few to several 10s of metres, and they frequently contain thin storm layers (tempestites), generating ribbon rocks. this type of parasequence tends to be more common in the transgressive parts of cyclic platform successions, or in the deeper-water, more distal parts of carbonate ramps. they are common throughout the geological record, and examples occur in the cambro-ordovician of north america (osleger & read, 1991; jennette & pryor, 1993) and china (meng et al., 1997), mississippian of northwest usa (elrick & read, 1991) and triassic muschelkalk of western europe (e.g., aigner, 1984). on a larger (3rd order) sequence scale, there are many examples of basinal mudrock–shallowwater limestone sequences. they are rather typical of carbonate ramp successions, and of course may themselves contain an internal smaller-scale cyclicity. examples of these occur within the carboniferous strata of south wales (burchette & wright, 1992) and the cretaceous of the central and western pyrenees (simo, 1989; lenoble & canerot, 1993) and austrian alps (sanders & höfling, 2000). broadly, the deeper-water mudrock lower parts represent transgressive facies, with the upper carbonates being prograding shallow-water highstand facies. the ‘grand cycles’ of the cambrian of the rocky mountains (canada), appalachians (usa; glumac & walker, 2000), china (meng et al., 1997) and elsewhere, are of this type. the terrigenous muds may well be supplied axially into the basin, rather than across the drowned carbonate platforms. this is particularly the case with foreland basins and narrow extensional basins, where carbonate platforms may be preferentially developed on one side. 5.2. lower carbonate – upper sandstone cycles thin sandstone beds at the top of metre-scale carbonate cycles were generally deposited in fluvial, clastic sabkha and aeolian environments when the carbonate platform was exposed; in some cases these sands were reworked into the basal layers of the next parasequence. sand layers are most common in the lowstand parts of cyclic successions, close to the sequence boundary zone. minor and major channels may have been cut into the platform during more significant sea-level falls. such thin sandstone beds are well described from the permian in texas, as in the yates formation (borer & harris, 1991), the permo-carboniferous in texas (saller et al., 1999) and the pennsylvanian of the paradox basin (goldhammer et al., 1994). minor sandstones also occur in the lowstand parts of lower palaeozoic cyclic platform carbonates. on the larger sequence-scale, after transgressive and highstand platform-carbonate deposition, often involving progradation through clinoforms, clastic sediments are commonly deposited during the lowstand, occurring within incised valleys cut during the falling stage, and as lowstand wedges on the foreslope of the platform and on the basin floor. this is the notion of reciprocal sedimentation: lowstand shedding of clastics and highstand shedding of carbonates. this pattern is well seen in the slope and basinal deposits of the quaternary of the caribbean area (schlager et al., 1994) where clastic input to the deep-sea was much greater during glacial times and carbonate input was higher during the interglacials, when carbonate platforms were flooded. ancient examples are documented from the cambrian of northern greenland (ineson & surlyk, 2000), devonian of the canning basin (southgate et al., 1993), the permian of texas (e.g., bone spring sands, saller et al., 1989), and the tertiary of northeast australia and gulf of papua (davies et al., 1989). a further type of carbonate–clastic sequence is where the limestones were deposited during the relative sea-level rise, and clastics deposited during the highstand/stillstand. the lower carbonates were initiated by a rapid sea-level rise such that there was little time for reworking of the coastal plain. however, a plentiful supply of terrigenous material is necessary in this scenario to generate the upper clastic unit, which is usually a coarsening-upward deltaic or shoreline deposit. this type of sequence is well-known from the mid-carboniferous of america (e.g., soreghan, 1997; rankey et al., 1999; miller & eriksson, 2000; smith & read, 2001) and western europe (see section 7 below). to illustrate the variety of clastic–carbonate sequences, two case studies are briefly presented of work that the author has been involved in over the last few years and which will be published in detail elsewhere. these are the quaternary deposits of the red sea coast of egypt where highstand carbonates are associated with lowstand clastics, and the midcarboniferous yoredale cycles of northern england, where transgressive carbonates are succeeded by highstand clastics. 22 geologia croatica 56/1 23tucker: mixed clastic–carbonate cycles and sequences... 6. quaternary of the red sea coast modern fringing reefs are beautifully developed along the red sea coast of egypt and in the gulfs of suez and aqaba, but they are also closely associated with episodic clastic influx. there are also fine examples of clastic–carbonate interaction in the pleistocene sequences exposed along the coast. this case study is based on visits to marsa alam, ~200 km south of hurghada on the egyptian red sea coast (location in fig. 1), in a collaborative project with the university of assiut. in this region, fringing reefs are well developed, attached to a low-cliffed shoreline (plate i, fig. 1) with major and minor dry river valleys (wadis) dissecting the coastal plain (plate i, figs. 2–4). the latter is 5 to 20 km wide and composed of quaternary and tertiary clastic and carbonate formations, backed by the red sea hills of precambrian metasediments and intrusives. 6.1. recent carbonate deposition reefal organisms are growing luxuriously in 0.5 to 30 m of water, along a generally steep to vertical reeffront. a great variety of corals is present, along with all the usual reef-associated fauna and flora. in many places the reef-front itself is indented with grooves and channels, and penetrated by tunnels and caves (plate ii, fig. 1). these features are cut into the late pleistocene (mis 5e) reefal limestone, upon and against which the modern reef is growing, and they relate to fluvial erosion and karstic dissolution during the last lowstand of sea-level (120 kyr–10 kyr bp) (see figs. 2, 3). the reef-flat immediately behind the reef-crest is a smooth to uneven rock surface that extends shorewards up to 100 metres (plate i, figs. 1, 4). much of this wave-cut platform is exposed at low spring tides and it is basically planed-off reefal limestone where corrosion and bioerosion are taking place. there is only very minor coral and coralline algal growth there. the reef-flat may extend to the shoreline to be covered by foreshore sands (clastic dominated) or there may be a mixed clastic, lime sand-floored lagoon, water depth <2 m, before the beach. 6.2. recent clastic deposition major wadi systems originating in the red sea hills deliver terrigenous sediment directly to fan deltas along the coast during floods (plate i, figs. 3, 4). the wadis cut through the fringing-reef system to form re-entrants (sharms), every 5–10 km along the coast. fan-delta sediments are reworked in shoreface and foreshore environments at wadi mouths and are mixtures of clastic and carbonate grains. ooids are locally precipitated in the shoreface areas here. minor wadi systems occur all along the coast (plate i, fig. 2), with spacings of 50–500 metres, but they do not disrupt the fringing reef. flash floods deposit sand and gravel at the shoreline and on the reef-flat, and fine material is carried over the reef-crest if the reef-flat is narrow with no lagoon to act as a sink. after a flood, terrigenous sediment on the reef-flat is reworked in the ensuing months and the fine material redistributed, either shorewards to form beaches or seawards to the fore-reef. clastic grains are also incorporated into reefflat limestones (plate ii, fig. 2). gravels on the reef-flat are wave-reworked to form bars and beaches, and then cemented and blackened (plate i, fig. 2). at the present-time, minor floods occur at any one location around once every 5 years and major floods every few decades. during a flood, the sea close to a wadi is coloured bright red from the suspended clay and this is deposited upon the corals over the ensuing few days. modern corals do have layers of clay and silt within their skeletal structure. the sediment transported through the wadis to the coast is relatively coarsegrained (reflecting the arid climate and dominant physical weathering), and the flood frequency is low at the present-time. over the long term the organisms on the reef-front do not appear to be affected by the floods, although corals close to the subaqueous wadi margins are frequently broken. 6.3. discussion of recent deposition the modern red sea coast does provide a cool example of syn-deposition of clastics and carbonates, as described earlier by purser et al. (1987), and several papers in purser & bosence (1998). however, at the present time, with an extremely arid climate in the region and a relative highstand of sea-level following termination of the last ice age, the clastic–carbonate fig. 1 location of field area near marsa alam, egypt. 22 geologia croatica 56/1 23tucker: mixed clastic–carbonate cycles and sequences... interaction is relatively minor: a) clastic beaches at the back of the carbonate platform with the terrigenous sediment derived from minor wadis draining the coastal plain, and b) clastics within major wadis cutting through the carbonate platform and feeding fan deltas. figure 4 presents a facies model summarising this clastic–carbonate system. on a longer-term perspective of a cycle of sea-level change, such as a glacial–interglacial cycle, the facies model will evolve. during a relative sea-level fall, carbonate sedimentation would be terminated as the platform and the reef-front became exposed. initially some clastics may be deposited across the reef-flat but with little and then decreasing accommodation space there, it could only be a thin layer. the platform would be subjected to karstification, and platformmargin collapse generating megabreccias would be likely. reefs might be established again when sea-level stabilised at its low point, although this would depend on the angle of the slope. the fluvial system would become incised during the forced regression of the falling stage, such that more terrigenous sediment would be supplied to the marine fan delta. whether more sediment would be generated in total would depend on the climate and frequency of floods. evidence from the region suggests that during the last glacial episode the climate was indeed wetter (lezine & casanova, 1991; plaziat et al., 1998), such that more clastic sedimentation would have been likely. the sequence model for this system is thus one of a highstand prograding reefal carbonate platform, with minor interbedded clastics at the shoreline, immediately overlain by very thin shoreface–foreshore clastics, and then fluvial facies, of the late highstand/early falling stage. fan deltas will be especially active during lowstands, particularly if the climate was more humid and flood frequency increased. during a subsequent sea-level rise, reworking of the clastics on the platform-top would provide the foundation for the next transgressive/highstand carbonate platform. fig. 2 sea-level curve for last 500,000 years (after shackleton, 1987). fig. 3 stratigraphy of the quaternary of the red sea coast, marsa alam, egypt. 24 geologia croatica 56/1 25tucker: mixed clastic–carbonate cycles and sequences... 6.4. pleistocene of the red sea coral reefs were well developed during the pleistocene of the red sea region and are now well-exposed along the coastal plain in egypt, adjacent to the modern fringing reefs. the reefs were deposited during interglacial highstands of sea-level, of which there were four during the last 500,000 years (see fig. 2 and papers in purser & bosence, 1998). interbedded with the pleistocene carbonates are terrigenous clastics of a variety of facies, but mostly well-sorted lithic sands and pebble conglomerates, with cross-bedding and lenticular bedding. these were deposited in shoreface–foreshore and fluvial environments, either contemporaneous with reef sedimentation, or during subsequent lowstands. this section focuses on the last-interglacial reefal unit exposed in the marsa alam area, which was deposited around 120–130,000 years ago, i.e. marine isotope stage (mis) 5e or 5.5 (figs. 2, 3). it shows some awesome features of clastic–carbonate interaction. this is an area where there has been no tectonic uplift for at least 1 million years. 6.5. last-interglacial reefal carbonates the mis 5e reef was deposited when sea level was up to 8 metres higher than present and so the deposits are well exposed in low cliffs along the modern coast. however, within the reefal unit there is clear evidence for a minor sea-level fall and rise, dividing the last-interglacial reef into two parts: the lower deposited during mis 5.53 and the upper during mis 5.51. this minor sea-level perturbation in mis 5e has been recorded elsewhere (bermuda, hearty, 2002; bahamas, kindler & hearty, 1996; and sardinia, kindler et al., 1997). indeed, along the red sea coastal plain subaqueous gypsum was deposited in lakes and bays at the time of the lowstand in the depression which was the former lagoon behind the reefs (orszag-sperber et al., 2001). the mis 5e reefal carbonates consist of large coral colonies up to several metres in diameter composed of montastrea, porites and galaxea (e.g., plate ii, fig. 3). there are many smaller corals, as well as molluscs, echinoids, calcareous algae and serpulids. there are also pockets and lenses of carbonate sand and gravel, with varying amounts of fine terrigenous material. landwards, the reefal unit passes into foreshore/shoreface conglomerates with a transition zone of mixed carbonates and clastics (plate ii, fig. 4). the reefal limestone appears to have grown on coarse pebbly–sandy terrigenous debris with marine shells and other fossils, although the base of the 5e reef is rarely seen. 6.6. clastics within mis 5e reefal carbonates within the last-interglacial reefal limestone, there is a marked disconformity at about 4 metres above the base, reflecting a sea-level fall. the disconformity can be found in many localities and is mostly a planar surface which can be followed for up to 100 metres in wadicliff exposures. it is interpreted as a wave-cut platform. in one locality (wadi mouran), there are low-angle dipping limestones below and horizontal coral-rich limestones above. at another locality (wadi shagra), the disconformity terminates landwards (500 metres from the present shoreline or 1000 metres from the modern reef-crest) at a well-developed wave-cut notch (plate iii, fig. 1). the surface here is overlain by gently offshore (eastward) dipping foreshore conglomerate and sandstone (up to 1.5 m thick), banked into the notch. traced laterally the clastics thin to less than 0.5 m. limestone with corals occurs above the clastics on the disconformity, and indicates a sea-level rise and resumed carbonate sedimentation. fig. 4 facies model for clastic–carbonate interaction, recent, red sea coast. 24 geologia croatica 56/1 25tucker: mixed clastic–carbonate cycles and sequences... there are also channel structures locally cut into the reef (e.g., wadi mouran), at the horizon of the disconformity, filled with well-sorted and rounded mixed clastic–carbonate sand (plate iii, fig. 2). these channels are interpreted as having been cut during the sea-level fall and filled during the subsequent mis 5.51 sea-level rise, which was then followed by the second stage of reefal limestone growth. in exposures in wadi samadai, several shingled, low-angle dipping conglomeratic lenses, prograding seawards, are present on the disconformity surface (plate iii, figs. 3, 4). they consist of well-sorted terrigenous gravel and lenses of sand, crudely bedded, with dispersed fossils of molluscs and coral fragments. these units are clearly foreshore deposits passing laterally (seawards) into thin lithic sand-dominated shoreface sediments. these marine deposits are a series of prograding clastic beaches upon a wave-cut platform, developed at a time of sea-level stillstand after the cutting of the wave-cut platform (fig. 5). the lenticular nature of the conglomerates suggests that there were periodic influxes of terrigenous gravel and sand to the shoreline. most likely these would have been brought to the shoreline by longshore drift from a major wadi. the regular arrangement of the beach lenses could indicate periodic climatic changes, and these would have been on the millennial scale. thus the latest pleistocene reefal unit of the red sea coast presents a useful example of clastic deposition within an overall carbonate succession and this was the result of a relatively small sea-level fall (probably the order of 3–4 metres). 7. mixed carbonate–clastic high-frequency sequences, mid-carboniferous, northern england high-frequency sequences are a feature of the midcarboniferous of europe and farther afield and carbonate–clastic cycles referred to as yoredale cycles are particularly well-developed in northern england. they occur within the carboniferous limestone and scremerston coal groups (fig. 6) (holkerian, midviséan, to mid-namurian) across the northumberland and stainmore basins and alston and askrigg blocks (fig. 7). there are up to 60 cycles with an average thickness of around 25 metres, and they are generally fig. 5 sea-level change and deposition, last interglacial reef (mis 5e/5.5), red sea. fig. 6 stratigraphy of the carboniferous of n.e. england. yoredale cycles occur within the scremerston coal group and limestone group, where lines represent limestone units. lines within the coal measures are major coal seams. 26 geologia croatica 56/1 27tucker: mixed clastic–carbonate cycles and sequences... thicker in the basins and thinner on the blocks. there was no surface expression of the boundaries between blocks and basins; they were simply areas of differential subsidence, although bounded by faults. the platform margin was located on the south side of the askrigg block in central yorkshire, with the deeper-water bowland/central pennine basin to the south. the yoredale cycles typically consist of a lower limestone unit, which can be correlated over several 100 sq km, and an upper coarsening-upward clastic succession of mudrocks to sandstones (see fig. 8 and plate iv). in many cases there is a palaeosoil and thin coal seam at the top, or several minor (metre-scale) cycles. 7.1. carbonate deposition typically, the yoredale limestones are well-bedded muddy bioclastic packstones–wackestones 1–20 metres thick (plate iv, fig. 1). corals, crinoids and brachiopods are the most abundant fossils, but calcareous algae, foraminifera, molluscs and bryozoans are also common. the limestones contain lenses and discontinuous layers of skeletal debris, probably the result of storm reworking. bioturbation is ubiquitous, mostly cmsized burrows, some with pelleted walls. locally there are small biostromes of larger colonial corals (0.3 m diameter), of siphonodendron especially, some of which may be overturned, or beds of the solitary coral dibunophyllum as in the famous frosterley ‘marble’. the basal bed (up to 0.5 m thick) of some limestones (also the basal bed of the cycle) is a prominent sandrich or clay-rich bioturbated packstone with fish scales, crinoids and brachiopods. the clastic material here is derived from reworking of the top of the cycle below. the limestones were probably deposited in water depths of 10–40 metres, in a generally quiet environment with only occasional storms. this was effectively an extensive and flat, low-energy platform, probably 150 km across, with a gentle slope with mud mounds and debrites into deeper water of the central pennine basin to the south. 7.2. clastic deposition two main types of clastic package occur above the limestone in a yoredale cycle (fig. 8): (1) a dominantly deltaic unit of prodelta mudrocks passing up into distal mouth-bar then proximal mouth-bar sandstones (fig. 8a; plate iv, figs. 2, 3). in some cases a channel sand-body cuts down into mouth-bar sandstone (plate iv, fig. 4). (2) a deep to shallow-marine succession of mudrocks to sandstones with tempestites and hcs from storms and a range of trace fossils, and then shoreface– foreshore crossand flat-bedded sandstones (fig. 8b). at several horizons in the succession, major lenticular sand bodies composed of cross-bedded medium to very coarse sandstone cut down 10 metres or more into the coarsening-upward unit, almost reaching the limestone at the base of the cycle (fig. 8c; plate iv, fig. 4). these shoestring sand-bodies show a fining-up of grainsize and a decrease of cross-bed set thickness, and in some cases wave-ripples and burrows towards the top. these sandstones are interpreted as incised-valley fills. at the top of the yoredale cycles, there is usually a palaeosoil (seatearth, fireclay, underclay, ganister) of variable grain-size, colour, thickness and texture. rootlets, nodules (siderite or calcrete), and/or polygonal cracks may be present, depending primarily on climate. a thin coal seam may complete the cycle (fig. 8), but is often absent. one or several metre-scale (‘minor’) coarsening-upward cycles may also occur at the top of the yoredale cycle (as in fig. 8a). these coastal-plain facies result from small deltas filling lakes and bays. fig. 7 location and palaeogeography, midcarboniferous, northern england/southern scotland. 26 geologia croatica 56/1 27tucker: mixed clastic–carbonate cycles and sequences... 7.3. origin of cyclicity the origin of the yoredale cycles has been much discussed with tectonic, eustatic and sedimentary mechanisms all put forward (e.g., leeder & strudwick, 1987). plots of cycle thickness variation through the succession (fischer plots) for several localities from both block and basin areas reveal a similar pattern, supporting the role of eustasy and/or regional tectonics (subsidence), but ruling out a local tectonic (i.e., fault) or sedimentary control. there is also a pattern through the succession in the facies distribution within cycles, with more carbonate-dominated cycles in the lower part of the succession and more clastic-dominated cycles in the upper part. there is also a trend in the clastic grainsize, with more coarse clastics in the upper asbian cycles and finer clastics in the cycles above and below. these patterns are related to the general decrease in marine influence and increase in clastic supply through the upper dinantian–namurian, a function of plate-scale tectonics, and a more arid climate in the upper asbian. although there is much uncertainty in the carboniferous time-scale, the duration of the yoredale cycles would appear to be the order of one to several 100,000 years. the mid-carboniferous was a period of glaciation in the southern hemisphere so that it is very likely that eustasy exerted a strong control on sedimentation. the cycles are interpreted as the result of the eccentricity orbital rhythm, most likely the long (400 kyr) one. 7.4. sequence stratigraphy from a sequence stratigraphic point of view, the yoredale cycles are interpreted as high-frequency sequences (model presented in fig. 9). the limestone units were clearly the result of rapid flooding and transgression across a low-relief coastal plain, with only local reworking of underlying sediments. a glacioeustatic mechanism best explains this. the carbonates are thus the transgressive systems tract. the progradation of deltaic shorelines or storm-dominated shorefaces, which led to the coarsening-upward clastic units, is the product of highstand deposition. the influx of the prodelta clay terminated carbonate production. the palaeosoils represent the late highstand, falling-stage and lowstand intervals, which may have been quite short periods of time judging by rates of sea-level change in the quaternary. the coals could have been generated during the earliest stages of sea-level rise, as accommodation space was beginning to be created, but their thin nature (or absence) followed by widespread deposition of the limestones suggests rapid sea-level rises. the major downcutting sand-bodies which occur at specific stratigraphic horizons are interpreted as incised-valley fills. they represent times of sharper and deeper glacioeustatic sea-level falls. the valleys would have fed lowstand fans in the central pennine basin to the south. 8. discussion: general patterns and trends with the different types of mixed-lithology cycle, the lithofacies succession depends on the rate of sea-level change and availability of clastics. slow sea-level rises can lead to extensive reworking of coastal-plain clastics and so well-developed clastic lower parts to cycles. more rapid sea-level rises cause flooding of coastal plains and so little reworking of sediment, especially if fig. 8 varieties of carbonate–clastic yoredale high-frequency sequence: a) limestone–deltaic clastics sequence with minor cycles at top; b) limestone–shoreline clastics sequence, c) incised-valley sandstone–limestone–deltaic clastics sequence. 28 geologia croatica 56/1 29tucker: mixed clastic–carbonate cycles and sequences... there had been extensive pedogenesis and/or vegetation cover, such that ravinement erosion was limited. at the other end of the sea-level cycle, stillstands allow alluvial-plain, shoreline and deltaic facies to prograde over highstand carbonates, with accommodation space determining thickness. a forced regression and the falling stage systems tract lead to platform exposure, river incision and the formation of lowstand fans and wedges on the basin-margin and incised-valley fills on the platform-top. mixed carbonate–clastic sequences are best developed at times of high amplitude sea-level change, and since these are typical of icehouse conditions, they are well-represented in the quaternary and permo–carboniferous. during these times the highfrequency sea-level fluctuations were on the scale of 10’s of metres and this was sufficient to bring terrigenous sediment into the depositional environment during a sea-level fall. the permo–carboniferous was also a time of first-order sea-level lowstand, in other words there were more of the continental landmasses exposed for weathering, erosion and denudation than at other times. the late palaeozoic was also a period of supercontinent assembly, when mountain ranges were forming, being uplifted and eroded. during greenhouse times, lower and mid-palaeozoic and mesozoic, low amplitude sea-level changes were the norm and extensive carbonate platforms and clastic shelf seas were typical. most shallow-marine, continental-shelf sequences of these periods are composed of single, uniform lithofacies, all clastic or all carbonate. the mixed carbonate–clastic sequences discussed here were rarely developed. mixed-lithology sequences may also involve cool-water carbonates, which are being increasingly recognised in the geological record and were deposited extensively around the mediterranean in the tertiary. however, it has recently been shown that these sediments respond in different ways to sea-level change with wave action generating shell beds during lowstands and sandstone units formed during the sealevel rise (brachert et al., 2003). thus, here it is a case of lowstand carbonates and highstand sandstones. the two examples of mixed clastic–carbonate formations discussed in this paper illustrate the variety that is encountered in the sedimentary record. however, much of this is due to the completely different climatic regime of the arid/semi-arid red sea in the quaternary versus equatorially-humid england in the carboniferous. in large part this is responsible for the difference in dominant clastic sediment type: coarse (sand–gravel) in the red sea versus fine (mud–sand) in the carboniferous. in both cases, carbonates were deposited during rising sea-level, after some reworking of coastal plain clastics. in the case of the red sea, carbonate deposition continued into the highstand with some minor intercalation of clastics along the shoreline from local fluvial input under the arid climate. in the carboniferous case, once sea-level had peaked, then, under the humid climate, clastic shorelines and deltas prograded rapidly across the platform during the highstand, and terrigenous prodelta mud inhibited and then terminated carbonate production. in both cases, during the falling stage and lowstand of sea-level, terrigenous clastics were funnelled through major wadis and incised valleys to fan deltas and lowstand wedges at fig. 9 depositional model for lower carbonate– upper clastic sequence based on yoredale cycles. 28 geologia croatica 56/1 29tucker: mixed clastic–carbonate cycles and sequences... the basin-margin. in the red sea, the exposed carbonate platform was karstified, whereas in the carboniferous, extensive palaeosoils developed on the subaeriallyexposed coastal-fluvial plain. 9. references aigner, t. (1984): dynamic stratigraphy of epicontinental carbonates, upper muschelkalk (m. triassic) south german basin.– neues jahrbuch für geologische und palaeontologie, abhandlungen, 169, 127–159. borer, j.m. & harris, p.m. (1991): lithofacies and cyclicity of the yates formation, permian basin: implications for reservoir heterogeneity.– am. ass. petrol. geol. bull., 75, 726–779. brachert, t.c., forst, m.h., pais, j.j., legoinha, p. & reijmer, j.j.g. (2003): lowstand carbonates, highstand sandstones?– sed. geol., 155, 1–12. braga, j.c., martin, j.m. & alcala, b. (1990): coral reefs in coarse-terrigenous sedimentary environments, upper tortonian, granada basin, southern spain.– sed. geol., 66 135–150. burchette, t.p. & wright, v.p. (1992): carbonate ramp depositional systems.– sed. geol., 79, 3–57. davies, p.j., symonds, p.a., feary, d.a. & pigram, c.j. (1989): the evolution of the carbonate platforms of northeast australia.– in: crevello, p.g., wilson, j.j., sarg, j.f. & read, j.f. (eds.): carbonate platform and basin development. soc. econ. petrol. min. (society for sedimentary geology) spec. publ., 44, 233–257. doyle, l.j. & roberts, h.h. (eds.) (1988): carbonate– clastic transitions.– elsevier, amsterdam, developments in sedimentology, 42, 304 p. elrick, m. & read, j.f. (1991): cyclic ramp-to-basin carbonate deposits, lower mississippian, wyoming and montana: a combined field and computer modelling study.– jour. of sed. petrol., 61, 1194–1224. glumac, b. & walker, k.r. (2000): carbonate deposition and sequence stratigraphy of the terminal cambrian grand cycle in the southern appalachians.– jour. of sed. res., 70, 952–963. goldhammer, r.k., oswald, e.j. & dunn, p.a. (1994): high-frequency glacio-eustatic cyclicity in the middle pennsylvania of the paradox basin: an evaluation of milankovitch forcing.– in: de boer, p.l. & smith, d.g. (eds.): orbital forcing and cyclic sequences. ias spec. publ., 19, 243–283. hearty, p.j. (2002): revision of the late pleistocene stratigraphy of bermuda.– sed. geol., 153, 1–21. ineson, j.r. & surlyk, f. (2000): carbonate megabreccias in a sequence stratigraphic context: evidence from the cambrian of north greenland.– in: hunt, d. & gawthorpe, r.l. (eds.): sedimentary responses to forced regression. geol. soc. of london spec. publ., 172, 47–68. jennette, d.c. & pryor, w.a. (1993): cyclic alternation of proximal and distal storm facies: kope and fairview formations (upper ordovician), ohio and kentucky.– jour. of sed. petrol., 63, 183–203. kindler, p. & hearty, p.j. (1996): carbonate petrography as an indicator of climate and sea-level changes: new data from bahamian quaternary units.– sedimentology, 43, 381–399. kindler, p., davaud, e. & strassser, a. (1997): tyrrhenian coastal deposits from sardinia (italy): a petrographic record of high sea-levels and shifting climate belts during the last interglacial (isotopic substage 5e).– palaeogeography, palaeoclimatology, palaeoecology, 133, 1–25. larcombe, p., costen, a. & woolfe, k.j. (2001): the hydrodynamic and sedimentary setting of nearshore coral reefs, central great barrier reef shelf, australia, paluma shoals, a case study.– sedimentology, 48, 811–835. leeder, m.r. & strudwick, a.e. (1987): deltamarine interactions: a discussion of sedimentary models for yoredale-type cyclicity in the dinantian of northern england.– in: miller, j., adams, a.e. & wright, v.p. (eds.): european dinantian environments. 115–130, john wiley & sons. lenoble, j.l. & canerot, j. (1993): sequence stratigraphy of the clansayesian (uppermost aptian) formations in the western pyrenees (france).– in: posamentier, h.w., summerhayes, c.p., haq, b.u. & allen, g.p. (eds.): sequence stratigraphy and facies associations. special publication international association of sedimentologists, 18, 283–294, blackwell scientific publications, oxford. lezine, a.m. & casanova, j. (1991): correlated oceanic and continental records demonstrate past climate and hydrology of north africa (0–140 ka).– geology, 19, 307–310. light, j.m. & wilson, j.b. (1998): cool-water carbonate deposition on the west shetland shelf: a modern distallysteepened ramp.– in: wright, v.p. & burchette, t.p. (eds.): carbonate ramps. geol. soc. of london spec. publ., 149, 55–71. meng, x., ge, m. & tucker, m.e. (1997): sequence stratigraphy, sea-level changes and depositional systems in the cambro–ordovician of the north china carbonate platform.– sed. geol., 114, 189–223. miller, d.j. & eriksson, k.a. (2000): sequence stratigraphy of upper mississippian strata in the central appalachians: a record of glacio-eustasy and tectonoeustasy in a foreland basin setting.– am. ass. petrol. geol. bull., 84, 210–233. mount, j.f. (1984): mixing of siliciclastic and carbonate sediments in shallow shelf environments.– geology, 12, 432–435. orszag-sperber, f., plaziat, j.c., baltzer, f. & purser, b.h. (2001): gypsum salina–coral reef relationships during the last interglacial (marine isotope stage 5e) on the egyptian red sea coast: a quaternary analogue for neogene marginal evaporites?– sed. geol., 140, 61–85. osleger, d. & read, j.f. (1991): relation of eustasy to stacking patterns of meter-scale carbonate cycles, late cambrian, usa.– jour. of sed. petrol., 61, 1225–1252. 30 geologia croatica 56/1 31 plaziat, j.c., baltzer, f., choukri, a., conchon, o., freytet, p., orszag-sperber, f., raguideau, a. & reyss, j.l. (1998): quaternary marine and continental sedimentation in the northern red sea and gulf of suez (egyptian coast): influences of rift tectonics, climatic changes and sea-level fluctuations.– in: purser, b.h. & bosence, d.w.j. (eds): sedimentation and tectonics of rift basins: red sea–gulf of aden. 537– 560, chapman & hall, london. purser, b.h. & bosence, d.w.j. (eds.) (1998): sedimentation and tectonics of rift basins: red sea–gulf of aden.– chapman & hall, london, 663 p. purser, b.h., soliman, m. & m’rabet, a. (1987): carbonate, evaporite and siliciclastic transitions in quaternary rift sediments of the northwestern red sea.– sed. geol., 53, 247–267. rankey, e.c., bachtel, s.l. & kaufman, j. (1999): controls on stratigraphic architecture of icehouse mixed carbonate–siliciclastic systems: a case study from the holder formation (pennsylvanian, virgillian), sacramento mountains, new mexico.– in: harris, p.m., saller, a.h. & simo, j.a. (eds.): advances in sequence stratigraphy: application to reservoirs outcrops and models. soc. econ. petrol. min. (society for sedimentary geology) spec. publ., 63, 127–150. saller, a.h., barton, j.w. & barton, r.e. (1989): slope sedimentation associated with a vertically building shelf, bone spring formation, mescalero escarpe field, southeastern new mexico.– in: crevello, p.g., wilson, j.j., sarg, j.f. & read, j.f. (eds.): carbonate platform and basin development. soc. econ. petrol. min. (society for sedimentary geology) spec. publ., 44, 233–257. saller, a.h., dickson, j.a.d., rasbury, e.t. & ebato, t. (1999): effects of long-term accommodation change on short-term cycles, upper palaeozoic platform limestones, west texas.– in: harris, p.m., saller, a.h. & simo, j.a. (eds.): advances in sequence stratigraphy: application to reservoirs outcrops and models. soc. econ. petrol. min. (society for sedimentary geology) spec. publ., 63, 227–246. sanders, d. & höfling, r. (2000): carbonate deposition in mixed siliciclastic–carbonate environments on top of an orogenic wedge (late cretaceous, northern calcareous alps, austria).– sed. geol., 137, 127–146. plate i carbonate–clastic interaction, recent, red sea coast, egypt 1 fringing reef and reef-flat along the coast near marsa alam and low cliffs of late pleistocene reef. 2 minor wadis supplying sediment to the shoreline. reef in mid-distance with reef-flat and lagoon in near-distance. 3 major wadi supplying terrigenous sediment to a fan delta. 4 major wadi entering the sea, cutting through fringing reef and feeding submarine fan delta. 30 geologia croatica 56/1 31tucker plate i 1 2 3 4 32 geologia croatica 56/1 33 santiseban, c. & taberner, c. (1988): sedimentary models of siliciclastic deposits and coral reef interactions.– in: doyle, l.j. & roberts, h.h. (eds.): carbonate–clastic transitions. elsevier, developments in sedimentology, 42, 35–76, amsterdam. schlager, w., reijmer, j.j.g. & droxler, a. (1994): highstand shedding of carbonate platforms.– jour. of sed. res., b64, 270–281. shackleton, n.j. (1987): oxygen isotopes, ice volume and sea level.– quat. sci rev., 6, 183–190. simo, a. (1989): upper cretaceous platform to basin depositional sequence development, tremp basin, south central pyrenees, spain.– in: crevello, p.g., wilson, j.j., sarg, j.f. & read, j.f. (eds.): carbonate platform and basin development. soc. econ. petrol. min. spec. publ., 44, 233–257. smith, l.b. & read, j.f. (2001): discrimination of local and global effects on upper mississippian stratigraphy, illinois basin, u.s.a.– jour. of sed. res., 71, 985–1002. soreghan, g.s. (1997): walther’s law, climate change and upper paleozoic cyclostratigraphy in the ancestral rocky mountains.– jour. of sed. res., 67, 1001–1004. southgate, p.n., kennard, j.m., jacson, m.j., o’brien, p.e. & sexton, m.j. (1993): reciprocal lowstand clastic and highstand carbonate sedimentation, subsurface devonian reef complex, canning basin, western australia.– in: locks, r.g. & sarg, j.f. (eds.): carbonate sequence stratigraphy. aapg memoir 57, 157–179. testa, v. & bosence, d.w.j. (1998): carbonate–siliciclastic sedimentation on a high-energy ocean-facing tropical ramp, ne brazil.– in: wright, v.p. & burchette, t.p. (eds.): carbonate ramps. geol. soc. of london spec. publ., 149, 55–71. wilson, m.e.j. & lockier, s.w. (2002): siliciclastic and volcaniclastic influences on equatorial carbonates: insights from the neogene of indonesia.– sedimentology, 49, 583–601. manuscript received february 7, 2003. revised manuscript accepted june 20, 2003. plate ii carbonate–clastic interaction, recent and pleistocene, red sea coast, egypt 1 modern reef-front with channels and tunnels cut into last interglacial, highstand reef during last glacial lowstand. 2 silt grains within modern reef-flat coral. 3 large coral colonies within last interglacial (mis 5e/5.51) reef. 4 large coral colonies in foreshore conglomerates and sandstones. last interglacial (mis 5e/5.51) reef (late pleistocene). 32 geologia croatica 56/1 33tucker plate ii 1 2 3 4 34 geologia croatica 56/1 35 plate iii carbonate–clastic interaction, pleistocene, red sea coast, egypt 1 reefal limestones with wave-cut platform and wave-notch overlain by beach gravels and sands. last interglacial (mis 5e/5.5) reef. 2 reefal limestone with a small incised channel of sandy-grainstone. 3 reefal limestones within which are shingled beach conglomerates upon a wave-cut platform. 4 two shingled beach conglomerate lenses upon reefal limestone (mis 5.51 reef). 34 geologia croatica 56/1 35tucker plate iii 1 2 3 4 36 geologia croatica 56/1 37 plate iv mid-carboniferous high-frequency sequences (yoredale cycles), ne england 1 the great limestone – the thickest carbonate (~20 m) of the yoredale cycles. weardale, co. durham. 2 coarsening-upward prodelta mudrock to mouth-bar sandstone above the howick limestone. howick, northumberland. 3 limestone (upon a palaeosoil) overlain by marine mudrock, then prodelta mudstone passing up into deltaic sandstone and palaeosoil/coal, before next limestone. scremerston, northumberland. 4 channel cutting into top part of yoredale cycle; basal limestone marked. howick, northumberland. 36 geologia croatica 56/1 37tucker plate iv 1 2 3 4 38 geologia croatica 56/1 04 balic.indd 27 � 1. introduction the goal for es ti ma tion is to get va lues of a cho sen va riab le for un sam pled loca tio ns. the re are dif fe re nt in ter po la tion met ho ds, and ea ch of them in clu des its own mat he ma ti cal ru les. the goal is to ac hie ve the in ter po la tion that is mo st si milar to the real geo lo gi cal dis tri bu tion in the re ser voir. in this pa per the re sul ts of four met ho ds: in ver se dis tan ce weig hti ng, nea re st neig hbour hood, mo vi ng ave ra ge and kri gi ng are com pa red. kri gi ng has pro ved to be the mo st ap prop ria te li near in ter po la tion met hod in the sen se of lea st squa re dif feren ces. ori gi nal ly this met hod was ap plied to go ld de po si ts of sou th af ri ca by the en gi neer d. g. kri ge, from whi ch the na me is de ri ved (krige,1951). this pio neer wo rk was fol lowed by stro ng theo re ti cal (mat he ma ti cal) de ve lop me nt in se ve ral techniques of kri gi ng. to day the se geos ta tis ti cal met ho ds are wi de ly used and rep re se nt a stan da rd pa rt of nu me rous met ho ds of stu dies ap plied to re ser voir roc ks. the dis tri bu tion of po ro si ty is ana lysed as the mo st im porta nt va riab le in the re ser voir. the met ho ds are tes ted usi ng da ta from the »t« re ser voir, whi ch be lo ngs to the 1st san dsto ne se ries of the kloš tar fi e ld (tab le 1) in the sa va dep res sion. the to tal num ber of re ser voir uni ts is 5. the se are the fol lowi ng uni ts (star ti ng wi th the ol de st): ba se me nt roc ks (»temelj no gor je«), mio ce ne (re ser voir ii, iii, iv, v, vi), lower pan nonian se di men ts, 2nd san dsto ne se ries (re ser voi rs al pha, be ta, gam ma) and 1st san dsto ne se ries (re ser voi rs ik, o, p, q, r, s, t, u, v, y, z) (tab le 1). the se are the fi r st po ro si ty ma ps in terpo la ted in pon tian re ser voi rs in the kloš tar fi e ld. da vo rin balić1, jo si pa velić2, to mis lav malvić1 ab stra ct the dis tri bu tion of po ro si ty da ta col lec ted at the kloš tar fi e ld is ana lysed. this fi e ld is lo ca ted in the nor th-wes te rn pa rt of the sa va dep res sion, and rep re sen ts one of the mo st lo ng-stan di ng fi el ds wi th res pe ct to oil pro duc tion in croatia, whe re pro duc tion has been on goi ng for mo re than 50 years. se ve ral re ser voi rs of ve ry di ver se lit ho lo gy and stratig rap hic age ha ve been dis co ve red. the olde st re ser voi rs (wi th mi nor oil re ser ves) oc cur in ba se me nt roc ks of the ter tia ry system (in for mal ly na med the »te melj no gor je«), then in ba de nian coar se-grai ned clas ti cs, as we ll as sandsto nes of pan no nian and pon tian ages. major re ser voi rs, wi th res pe ct to si ze, num ber and vo lu me, are lo ca ted in se di men ts of the up per pan no nian and lower pon tian. the se are me diu m-grai ned san dsto nes, mos tly quar tz-mi ca grai ns, mu tual ly se pa ra ted by mar ls. re ser voi rs of lower pon tian age oc cur wit hin who le struc tu res (an tic li nes) at kloš tar, whi le the up per pan no nian has been de ve lo ped on ly in the sou th–we st pa rt. ear lier stu dies on the re ser voirs ha ve in clu ded on ly se ve ral mea su red va lues of re ser voir po ro sity. the se va lues have not been map ped, but on ly a unique ave ra ge va lue, cha rac te ris tic for the who le re ser voir was cal cu la ted. rein ter pre ta tion of e-lo gs in crea sed the num ber of in put va lues to 20 poi nts of da ta. ru les are de ter mi ned for the dis tri bu tion of po ro si ties in the lar ge st reser voir of the lower pon tian na med »t«. the se re gu la ri ties can be tran sla ted to the ot her san dsto ne re ser voi rs. several in ter po la tion met ho ds we re se lec ted (in ver se dis tan ce, nea re st neig hbour hood and mo vi ng ave ra ge), wi th spe cial em pha sis on kri gi ng. the in ter po la ted ma ps are dif fe re nt. ba sed on a com pa ri son of iso po ro si ty, li nes, sha pes, and cro ss-va li da tion re sul ts, kri gi ng was eva lua ted as the mo st ap prop ria te met hod for po ro si ty in ter po la tion. keywor ds: oil, 1st san dsto ne se ries, po ro si ty, geos ta tis ti cs, kri gi ng, pon tian, kloš tar, croa tia 1 re ser voir en gi nee ri ng & fie ld de ve lop me nt, ina – oil in dus try plc., zag reb, croa tia (davo rin.balic@ina.hr, to mis lav.malvic@ina.hr) 2 fa cul ty of mi ni ng, geo lo gy and pet ro leum en gi nee ri ng, zag reb, croa tia (jo si pa.velic@rgn.hr) se lec tion of the mo st ap prop ria te in ter po la tion met hod for san dsto ne re ser voi rs in the kloš tar oil and gas fi e ld geologia croatica 61/1 27–35 10 figs. 1 tab. zagreb 2008 geologia croaticageologia croatica � 04 balic.indd 2704 balic.indd 27 24.6.2008 11:08:2524.6.2008 11:08:25 geologia croatica geologia croatica 61/1 28 2. geographic location and basic geology of the kloštar field the kloš tar fi e ld is lo ca ted in the area of the kloštar-ivanić, pre da vec, šća po vec, so bo ća ni, pr kos, gor nji ša ram pov and li po vac vil la ges, i.e. in the kloš tar, iva ni ć-grad and br ckovlja ni dis tric ts. it is lo ca ted about 35 km east of zag reb (fi gu re 1). in clo se proxi mi ty to the sou th-ea st, lie the pro duc tion oil fi el ds of šumečani and bu nja ni. lu pog lav fi e ld lies to the nor thwe st, and the ivanić fi e ld is to the sou th. the kloš tar fi e ld co ve rs an area of arou nd 30 km2, and ad mi nis tra ti ve ly be lon gs to zag reb coun ty, and the re gio nal geo lo gi cal unit of the sa va dep res sion (fi gu re 1). the hydro car bon re servoi rs are in lit hos tra tig rap hic uni ts of mio ce ne age na med the pre čec, iva ni ć-grad (oko li san dsto nes) and kloš tar ivanić (po lja na san dsto nes) for ma tio ns. minor oil re ser ves al so oc cur in roc ks of pa laeo zoic age. ge ne ral ly, the re are twen ty stra ti fi ed and/or mas si ve re ser voi rs pro ven, for mi ng 5 uni ts na med (from the ol de st) ba se me nt roc ks (»te melj no gor je«), mio ce ne, lower pan no nian, 2nd san dsto ne se ries and 1st san dsto ne se ries (tab le 1). the ave ra ge ef fec ti ve thic kne ss of par ti cu lar re ser voi rs is 5 metres. the per mea bi li ty va ries be tween 2.4 and 179.9 x 10–3 µm2. the re are a to tal of 196 wel ls dril led to da te. of the se, 64 are clas si fi ed as mea su ri ng wel ls, 59 are in pro duction, 68 are aban do ned and 5 wel ls are used for the injec tion of was te wa ter1. the sche ma tic map of we ll lo ca tio ns in the kloš tar fi e ld is shown in fi gu re 2. 3. historical exploration of the kloštar area geo lo gical re sear ch in the area of kloš tar be gan at the be ginni ng of the 20th cen tu ry. gas tra ces in wel ls of kloš tar, iva nić, and sur roun di ng vil la ges we re known from an cie nt ti mes. fac to rs in di ca ti ng the pre sen ce of hydro car bo ns re sul ted in the fi r st we ll bei ng dril led to a dep th of 905 m in 1904/5. gas was no ti ced at a dep th of arou nd 650 m, but oil had not been dis co ve red. regio nal gra vi met ric sur veyi ng of nor th-we st croa tia be tween 1940–1942 in clu ded the area of the kloš tar fi e ld. gra vi met ric stu dies then hig hlig hted a struc tu re cal led »križ« wi th a di na ri dic stri ke (nw–se), in whi ch the šu meča ni (dis co ve red in 1948), bu nja ni (dis co ve red in 1952) and lu pog lav (dis co ve red in 1971) oil fi el ds are lo ca ted. on the nor th-we st pa rt of the križ struc tu re, in the area of kloš tar, the re has been a mo ve towar ds im ple men ti ng new gra vi met ric mea su re me nt met ho ds sin ce 1952. in ter pre ta tion of the re sul ts fa ci li ta ted the lo ca tion of the fi r st explo ra tion we ll kloš ta r-1 (klo-1). a dep th of 1272 m was ac hie ved in this we ll. the fi ve re ser voi rs, wi th to tal dep th of 853–990 metres have been dril led, to par ti cu lar dep ths as fol lows: a (853–865 m), p (873–875 m), q (891.5–898.5 the m), r (914– 915 m) and y (987–990 m). an in dus trial ly sig ni fi ca nt amou nt of oil was dis co ve red. the kloš tar fi e ld was put into pro duction in 1954. on se ve ral oc ca sions in la ter yea rs, the den si ty of the ne two rk of seis mic pro fi les was in crea sed, es pe cial ly in the mar gi nal par ts of fi e ld, for the pur po se of fi e ld con tou ri ng and de fi ni tion of pet ro leum geo lo gy set tin gs. be tween 1954– 1961 new wel ls we re dril led, re co ve ry was in crea sed usi ng wa ter injec tion and the fi e ld boun da ries were exten ded. all the se ac hie ve men ts led to in crea ses in the re ser ves, whi ch ha ve been mo ni to red2 du ri ng who le pe riod of pro duc tion. fur thermo re, pos sib le new amoun ts of hydro car bo ns in so-cal led hid den tra ps ha ve been es ti ma ted3. 1 re po rt of hydro car bon re ser ves of the kloš tar fi e ld, pro fes sio nal do cu men ta tion of ina – reser voir en gi nee ri ng and fie ld de ve lopme nt de pt., 1977; at las of oil and gas fi el ds, pro fes sio nal do cu menta tion of ina – re ser voir en gi nee ri ng and fie ld de ve lop me nt dept., 1998, re po rt of hydro car bon re ser ves of the kloš tar fi e ld, pro fes sio nal do cu men ta tion of ina – reser voir en gi nee ri ng and fie ld de ve lop me nt de pt., 2002; stu dy of stei ner et al. from pro fessio nal do cu men ta tion of ina, 1999 2 re po rt of hydro car bon re ser ves of the kloš tar fi e ld, pro fes sio nal do cu men ta tion of ina – re ser voir en gi nee ri ng and fie ld de ve lopme nt de pt., 1977; re po rt of hydro car bon re ser ves of the kloš tar fi e ld, pro fes sio nal do cu men ta tion of ina – re ser voir en gi nee ri ng and fie ld de ve lop me nt de pt., 2002 3 stu dy of stei ner et al. from pro fes sio nal do cu men ta tion of ina, 1999 fi gu re 1: geog rap hic lo ca tion of the kloš tar fi e ld fi gu re 2: sche ma tic map of we ll lo ca tio ns at the ana lyzed fi e ld 04 balic.indd 2804 balic.indd 28 24.6.2008 11:08:2624.6.2008 11:08:26 geologia croatica 29 da vo rin balić et al.: se lec tion of the mo st ap prop ria te in ter po la tion met hod for san dsto ne re ser voi rs in the kloš tar oil and gas fi e ld many ot her re gio nal stu dies ha ve in clu ded in ves ti ga tion of the kloš tar fi e ld as pa rt of explo red area. pet rop hysi cal pro per ties of the san dsto nes as we ll as stra tig rap hic ar chi tectu re in the wes te rn pa rt of the sa va dep res sion have been we ll de fi ned by jüttner et al. (2001), saftić (1998) and saftić et al. (2001). velić & saftić (2000) pub lis hed a ge ne ral pa per about hydro car bo ns in croa tia, and fi nal ly cvetković (2007) ap plied neu ral ne twor ks for log ana lysis in the san dsto ne re ser voi rs in the kloš tar fi e ld. 4. petroleum geology settings the križ struc tu re (in clu di ng the kloš tar fi e ld) is lo ca ted at the mo st nor th-wes te rn pa rt of mos la vač ka go ra mt. du ri ng the lower and mid dle mio ce ne, a lar ge pa rt of mos la vač ka go ra mt. was up lif ted abo ve sea-le vel. the križ struc tu re has di na ric orien ta tion (nw–se), and it is for med from prepa laeo zoic gra ni tes and gneis ses (vragović & majer, 1980; pamić et al., 1984). the main nor the rn fau lt of the sa va dep res sion was pa ral lel wi th the sout he rn mar gin of this struc tu re. despi te a lar ge num ber of we ll da ta, the boun da ries be tween stra tig rap hic uni ts are of ten not pre ci se ly de fi ned, mos tly due to the in suf fi cie nt num ber of palaeon to lo gi cal sam ples and a lar ge num ber of tec to nic bloc ks. at fa vou rab le lo ca tio ns, stra tig rap hic boun da ries are de ter mi ned from availab le we ll da ta (co res, mud par tic les and lo gs). the re are fi ve re ser voir se ries de fi ned in to tal, star ti ng wi th pa laeo zoic roc ks and en di ng wi th lower pon tian se di men ts. the ba se me nt ter tia ry system in clu des erup ti ves and me ta mor phic roc ks, gra ni tes and gneis ses of pa laeo zoic age. this is a buried hi ll for med be fo re the ter tia ry (i.e. mio ce ne) pe riod, by ra dial tec to nic mo ve men ts and de nu da tion pro cesses. the roc ks are weat he red and ca tac li sed. this explai ns why so me par ts, in struc tu ral ly fa vou rab le pla ces, are con fi r med as oil re ser voi rs. the mid dle mio ce ne (ba de nian, sar ma tian) was de po sited pe ric li nal ly over the palaeo zoic mag ma ti c-me ta mor phic un con for mi ty, i.e. se di men ta tion was not con ti nuous. the mid dle mio ce ne stra tig rap hy is ve ry he te ro ge neous. the se se dimen ts be gin wi th coar se-grai ned con glo me ra tes, con glo me ra tic san dsto nes and san dsto nes of ten in ter ca la ted wi th sha les. they are over lain by da r k-grey, san dy and bi tu mi ni sed mar lsto nes, par tial ly in ter ca la ted wi th lig ht-grey, fi ne-grai ned san dsto nes. mio ce ne be ds from eco no mic hydro car bon re ser voi rs at the sout he rn and eas te rn par ts of the kloš tar struc tu re. the up per mio ce ne (pan no nian, pon tian) is pro ven and explo red throug hout the en ti re fi e ld. lower pan no nian stra ta were con cor dan tly de po si ted over sar ma tian bi tu mi ni sed mar lsto nes. this is a clear ly re cog ni sed fa cies of ha rd, whi te cal ci tic mar lsto nes, whi ch can be dis tin guis hed from the se dimen ts abo ve and be low on their lit ho lo gi cal and elec tro-physical pro per ties (pletikapić, 1969). the re are of ten re la ti vely thin be ds of lig ht-grey, fi ne-grai ned san dsto nes that are sa tu rated wi th sig ni fi ca nt oil re ser ves in the sout he rn pa rt of the fi e ld. up per pan no nian se di men ts were de po si ted over the en ti re fi e ld. the se are mos tly brown or da r k-grey, ha rd cal citic mar lsto nes. three san dsto ne se ries (na med as alpha, be ta and gam ma) are pre se nt in the sou th-wes te rn pa rt and are par tial ly sa tu ra ted wi th hydro car bo ns. this is al so cal led the 2nd san dsto ne se ries. the be ta re ser voir in clu des the lar ge st re ser ves and grea te st pro duc tion. lower pon tian se di men ts are de fi ned as (da rk) grey, com pa ct mar lsto nes and san dy mar lsto nes in the sou th and ea st of the fi e ld. san dsto nes, that cou ld be clean or in clude sma ll pro por tio ns of ma rl or clay, are do mi na nt in the nor th– we st. the san dsto ne re ser voi rs are na med, from the top, as g, h, i, k, l, m and n. these are mos tly sa tu ra ted wi th wa ter, exce pt for so me spo ra dic tra ces of gas (g and h) or oil (i and k). dee per in ter va ls are na med o, p, q, r, s, t, u, v, y and z, whi ch are the main oil re ser voi rs of the fi e ld. the mo st im por ta nt in ter va ls are t, u and v. the uni ts o–z fo rm the 1st san dsto ne se ries. the up per pon tian se di men ts are con cor da nt and oc cur over the en ti re fi e ld. the lit ho lo gy is mo no to nous, con sis ti ng of so ft san dy or clayey se di men ts. the propor tion of sa nd in crea ses upwar ds. the plio ce ne, i.e. da cian and ro ma nian, is al so known as the »pa lu di na« be ds. the se se di men ts mos tly in clu de clays in al ternation wi th me diu mand coar se-grai ned san ds. the qua ter na ry con si sts mos tly of yel lowi sh, san dy clay se di men ts wi th nu me rous li me con cre tio ns. the ave ra ge thickne ss is be tween 10 and 15 metres. the kloš tar struc tu re is a faul ted an tic li ne wi th di na ric stri ke. the geo lo gi cal his to ry is ve ry in te res ti ng, as dis co vered du ri ng in ves ti ga tion of the struc tu ral de fi ni tion and pa laeotec to nic evo lu tion of the wes te rn pa rt of the sa va dep res sion (velić, 1979; 1980; 1983). the fi e ld struc tu re was for med in the mid dle mio ce ne, ac com pa nied by stro ng uplif ti ng even ts in the ba de nian and sar ma tian. at that ti me, an an ticli ne was crea ted, wi th di men sions of 7 x 2 km wi th a nw–se orien ta tion. la ter, in the up per mio ce ne, this struc tu re was dif fe ren tia ted into two smal ler par ts: the nor the rn whi ch was up lif ted throug hout the pon tian, and the sout he rn pa rt whi ch was on ly acti va ted in the up per pon tian. in the sa me pe riod the par ti cu lar bloc ks be tween these up lif ted areas gra dual ly sub si ded, es pe cial ly in the lower pon tian. the re ce nt struc tural sha pe was tec to ni cal ly crea ted in the plio ce ne and qua terna ry, when the main pha se of hydro car bon mig ra tion pro bab ly oc cur red. the kloš tar struc tu re was bor de red by the prin ci pal nor the rn fau lt zo ne of the dep res sion. the ver ti cal dis pla ceme nt, at the le vel of mar ker »tg« (ba se me nt top), is al mo st 1000 metres. this is why the geo lo gi cal set ti ng of the fi e ld is ve ry com plex. su ch a lar ge dis pla ce me nt is al so refl ec ted in the fa ct that the re ser voi rs of the 1st san dsto ne se ries are dis loca ted in 17 bloc ks (fi gu re 3). the re ser voi rs of the 1st san dsto ne se ries (tab le 1, fi gu re 4, na med as z, y, v, u, t, r, s, p, p, o and ik) be lo ng to the lower pon tian be ds. the pa rt of the 1st san dsto ne se ries that is sa tu ra ted wi th hydro car bo ns co ve rs the nor th-eas te rn pa rt of the fi e ld. the struc tu re gen tly sin ks towa rd the nor th–we st. ac cor di ng to the clas si fi ca tion of oil and gas re ser voi rs gi ven by brod (in aksin, 1967), the hydro car bon re ser voi rs of the 04 balic.indd 2904 balic.indd 29 24.6.2008 11:08:2724.6.2008 11:08:27 geologia croatica geologia croatica 61/1 30 poi nt da ta (9) the ave ra ge re ser voir po ro si ties are cal cu la ted as arit hme ti cal means. the kloš tar fi e ld is cha rac te ri sed by a ve ry lo ng pro duction pe riod. it has al rea dy las ted 53 yea rs and the next 20 yea rs of pro duc tion are plan ned (fi gu re 5). the re fo re, em pha sis is gi ven to the in ter pre ta tion of ad di tio nal lo gs and cal cu la tion of new pet rop hysi cal va lues. this was do ne in 2007 for 20 rep re sen ta ti ve wel ls. the ave ra ge po ro si ties for ea ch re ser voir we re cal cu la ted, and this pa ra me ter was es pe cial ly inter po lated in san dsto ne re ser voir »t«, as it is the lar ge st and mo st typi cal san dsto ne re ser voir. 1st san dsto ne se ries rep re se nt a group of stra ti fi ed be ds de li neated by tec to nic and lit ho lo gi cal bar rie rs. the ana lysed re servoir »t«, to get her wi th re ser voirs u and v, rep re se nts the mo st im por ta nt re ser voir of the 1st san dsto ne se ries. the mar lsto ne that se pa ra tes re ser voi rs t, u and v from ea ch ot her is fou nd in the cen tral pa rt. the se re ser voi rs con si st of fi neto me diu mgrai ned, weak san dsto nes, wi th a maxi mum thic kne ss up to 10 metres. the mar lsto nes gra dual ly di sap pear at the ea st of the struc tu re, al lowi ng pos sib le con nec tion of re ser voi rs »t« and »u«. the ave ra ge re ser voir pa ra me te rs are cal cu la ted usi ng weig hte ni ng and the ef fec ti ve thic kne ss of the ana lysed in terva ls. the la bo ra to ry po ro si ty da ta are de ri ved from the 51 co res from 9 wel ls. due to the sma ll num ber of ho ri zon tal age lit ho-strat. uni ts re ser voir se ries re ser voi rs ce n o zo ic m io ce n e u pp er m io ce n e lower pontian kloš ta r-i va nić fm. 1st san dsto ne se ries ik, o, p, q, r, s, t, u, v, y, z upper pannonian ivanić-grad fm. 2nd san dsto ne se ries al pha, be ta, gam ma lower pannonian prkos fm. pre-va len cien be ds m id d le m io ce n e badenian, sarmatian prečec fm. mio ce ne ii, iii, iv, v, vi paleozoic ba se me nt »te melj no gor je« table 1 sche ma tic re view of the chro no-, lit hos tra tig rap hic and re ser voir uni ts fi gu re 3: struc tural map of »t« re ser voir top (1st san dsto ne se ries). drawn after note 3 4 atlas of oil and gas fi el ds, pro fes sio nal do cu men ta tion of ina – reser voir en gi nee ri ng and fie ld de ve lop me nt de pt., 1998 fi gu re 4: sche ma tic geo lo gi cal cro ss-sec tion of the 1st san dsto ne se ries4 04 balic.indd 3004 balic.indd 30 24.6.2008 11:08:2724.6.2008 11:08:27 geologia croatica 31 da vo rin balić et al.: se lec tion of the mo st ap prop ria te in ter po la tion met hod for san dsto ne re ser voi rs in the kloš tar oil and gas fi e ld 5. applied interpolation methods the es ti ma tion, i.e. in ter po la tion, can be do ne from known va lues of the ob ser ved pri ma ry va riab le (au to cor re la tion,) or by usi ng one or mo re al ter na ti ve se con da ry va riab les in the sa me area. a stro ng cor re la tion be tween the pri ma ry and se conda ry variab les is the on ly con di tion requi red. the re are va rious es ti ma tion met ho ds, i.e. dif fe re nt in ter po la tion tec hniques. the ap plied prog ram sur fer 8.0tm al lows the use of twel ve in ter po la tion met ho ds. he re, four met ho ds are com pa red: in ver se dis tan ce weig hti ng, nea re st neig hbour hood, mo vi ng ave ra ge and kri gi ng. the in ver se dis tan ce weig hti ng met hod es ti ma tes va lues from a re la ti vely sim ple mat he ma ti cal expres sion (equa tion 1). the in fl uen ce of ea ch poi nt is in ver sely pro portio nal to the dis tan ce from an es ti ma ted lo ca tion. the num ber of poin ts in clu ded in the es ti ma tion (z1...zn), is de fi ned by cir cle ra dii drawn arou nd a se lec ted lo ca tion. the re su lt is stron gly de pe ndent on the va lue of the dis tan ce expo ne nt (p). most of ten this va lue is set at 2 (as he re). the main rea son of the po pu la ri ty of a va lue of 2 for the dis tan ce expo ne nt is the gen tly smoot hi ng cha rac te ris tic of this expo ne nt (jános gei ger, pe rs. co mm. 2007). in the ca se of p=1, a sim ple li near in ter pola tion can be drawn. for p=3 re la ti ve ly sma ll dis tan ces are em pha si sed, but from a par ti cu lar dis tan ce the weig htings can in crea se dras ti cal ly. so if the ope ra tor has a men tal pic tu re of the geo lo gi cal la te ral va ria tion, the re is the pos si bi li ty of hig hlig hti ng fea tu res in clu di ng thin im per meab le bar rie rs, by usi ng a lar ge va lue for p. 1 1 ... 1 ... z d d d d z d z d z 2 1 2 2 iu i p p n p i p p n p n = + + + + (equa tion 1) whe re: ziu – es ti ma ted va lue d1...dn – dis tan ces of lo ca tio ns 1...n to the es ti ma ted lo cation ziu p – dis tan ce expo ne nt z1...zn – real va lues at lo ca tio ns 1...n the nea re st neig hbour hood met hod as sig ns the va lue of the clo se st poi nt to ea ch grid no de. it is not so mu ch an interpo la tion met hod as a zo nal assig nme nt tec hnique. this met hod is use ful in the ca se of re la ti ve lar ge zo nes wit hout da ta (bli nd areas), whi ch need to be sche ma ti cal ly map ped. the si ze of the zo ne that nee ds to be »ap prop ria te« is es ti ma ted from the de fi ned sin gle da ta, ba sed on the type of map ped va riab le. the mo vi ng ave ra ge met hod cal cu la tes the va lues of grid no des from ave ra ged da ta mea su red in a par ti cu lar el lipsoid or cir cle that sur rou nds ea ch grid no de. the re is al so a need to de fi ne the lowe st num ber of da ta that can be ave ra ged. if the num be rs of da ta in si de the de fi ned area are lower than the mi ni mum, the no de va lue wi ll not be cal cu la ted. this is not exa ct in ter po lation but rat her a ki nd of sim ple met hod cha rac te ri sed by its tri vial smoot hi ng cha rac ter. the re are so me ap pli ca tions when this met hod can al so be ap plied to the late ral smoot hi ng of da ta. kri gi ng is a geos ta tis ti cal met hod, ba sed on cal cu la tions of spa tial de pen den ce, i.e. expe ri men tal va riog ra ms. the theo ry of va riog ram ana lysis is explai ned in nu me rous boo ks and pa pe rs. su ch ana lyses are per for med at se ve ral fi el ds in the croa tian pa rt of the pan no nian ba sin system, i.e. for the sig nifi ca nt num ber of core da ta col lec ted in the bje lo var sub dep ression (hernitz et. al., 2001; malvić, 2003; 2005; malvić & đureković, 2003). ter mi no lo gi cal ly, the ter ms va riogram and se mi va riog ram (e.g. see isaaks & srivastava, 1989; journel & huijbregts, 1978; hohn, 1988; jensen et al., 1997; malvić, 2003) are iden ti cal, be cau se the va riog ram equa tion can be sim pli fi ed in a way whe re by bo th si des are mul tip lied by ‘2’. the ob tai ned fun ction (equation 2) is cal led a se mi va riog ram and is writ ten as: h n h z u z u h2 1 n n n n h 2 1 #c = + = ^ ^ _ _ ^ h h i i h 8 b! (equa tion 2) whe re: n(h) – num ber of da ta pai rs com pa red at dis tan ce ‘h’ z(un) – va lues at lo ca tion un z(un+h) – va lues at lo ca tion un+h. fi gu re 5: pro duc tion ra tes and dyna mi cs (from: atlas of oil and gas fi el ds, pro fes sio nal do cu men ta tion of ina-re ser voir en gi nee ri ng and fie ld de ve lop me nt de pt., 1998) 04 balic.indd 3104 balic.indd 31 24.6.2008 11:08:2924.6.2008 11:08:29 geologia croatica geologia croatica 61/1 32 al mo st all expe ri men tal (se mi)va riog rams can be mat hema ti cal ly ap proxi ma ted by fi ve theo re ti cal mo de ls: sphe ri cal, expo nen tial, gaus sian, li near and lo ga rit hmic (hohn, 1988). the kri gi ng es ti ma tion in clu des the fol lowi ng cri te ria: · it nee ds to be un bia sed, · the diffe ren ce of va rian ces be tween the mea su red and es ti ma ted va lues (so cal led kri gi ng va rian ce) nee ds to be at the lowe st pos sib le va lue. the kri gi ng al go rit hm al so cal cu la tes the pre dic ted and real es ti ma tion er ro rs. the se va lues can be com pa red wi th mea su red va lues (or in put da ta), and the re lia bi li ty of es ti mation can be cal cu la ted. kri gi ng is des cri bed as a sta tis ti cal tec hnique cal led »blue«. the ac ro nym blue mea ns best li near un bia sed es ti ma tor. the sim ple kri gi ng for mu la for es ti ma tion ba sed on »n« con trol poin ts (ha r d-da ta) is gi ven in equa tion 3: z zk i i n i 1 #m= = ! (equa tion 3) whe re: li – weig hti ng coef fi cie nt for ea ch lo ca tion »i« zi – sur roun di ng known va lues, so cal led con trol poin ts zk – va lue es ti ma ted by kri gi ng the kri gi ng met hod is di rec ted to es ti ma tion of an ap propria te weig hti ng coef fi cie nt and fi nal ly a va lue zk. the set of zk va lues is ob tai ned by ap plyi ng a mat rix system of li near kri gi ng equa tio ns. cro ss-va li da tion is a rela ti ve ly sim ple nu me ri cal met hod ve ry of ten ap plied in chec ki ng the es ti ma tion qua li ty. it is ba sed on mo vi ng mea su red va lues at cer tain lo ca tions and es tima ting new va lue at the sa me pla ce. new es ti ma tions are ba sed on the re mai ni ng mea su red da ta (equa tion 4). the pro ce du re is re pea ted for all wel ls and a fi nal va lue cal led the mean squa re er ror (mse) is cal cu la ted. the met hod’s di sadvan ta ge is its in sen si tivity to the num ber of ana lysed wel ls. the famous pio neer wo rk on cro ss-va li da tion was pub lis hed by davis (1987). in a geo lo gi cal sen se, the mse va lue in dica tes an er ror ob tai ned from the exis ti ng da ta set usi ng a dif fere nt in ter po la tion al go rit hm. for exam ple, if the dep th of stra ta is map ped usi ng two met ho ds and the sa me in put da ta set, ea ch map wi ll be cha rac te ri sed by a dif fe re nt mse va lue (equa tion 4). mo reo ver, a lower mse va lue in di ca tes the mo re ap propria te in ter po la tion, i.e. the lower er ror ob tai ned by n-1 da ta ana lysed sequen tial ly. cal cu la tion of mse can be ap plied to al mo st all geo lo gi cal va riab les in clu di ng po ro si ty, sa tu ra tion and ot hers. mse n real value estimation1 i i n 2 1 = = ^ h! (equa tion 4) whe re: mse – re sul ts ob tai ned by cro ss-va li da tion (mean squa re er ror) real va lue – va lue ob tai ned at lo ca tion »i« es ti ma tion – va lue es ti ma ted at lo ca tion »i« 6. results of a comparison of interpolation methods inter po la tion from 20 po ro si ty va lues was used as the in put. this is a ve ry li mi ted da ta set for the cal cu la tion of an expe rimen tal va riog ram. there fo re, di rec tio nal va riog ra ms we re omit ted and on ly the om ni di rec tio nal ones (i.e. bei ng in de pende nt of di rec tion) we re cal cu la ted. in put da ta we re ave ra ged log mea su re men ts col lec ted for re ser voir »t« and rein ter preted in 2007. rein ter pre ta tion was ba sed on the neut ron and den si ty lo gs (cdl – com pen sa ted den si ty log i cnl – com pen sa ted neut ron log). due to a hig her num ber of lo gs and bet ter sof twa re sup po rt, the qua li ty of the rein ter pre ted va lues is mu ch grea ter than those es ti ma ted in the pa st. in any par ti cu lar we ll the ve ry den se lo g-po ro si ty va lues we re rep laced by a sim ple ave ra ge va lue cal cu la ted for the who le re servoir thic kne ss. the new da ta set ma de it pos sib le to ap ply and com pare se ve ral in ter po la tion met ho ds and re sul ts. re sul ts ob tai ned by four met ho ds are pre sen ted on dif fere nt ma ps. al mo st all, can be re cog ni sed by their ve ry dif fere nt mor pho lo gies, des pi te the sma ll si ze of the in put da ta set. the di re ct re sul ts of the mat he ma ti cal al go rit hms are used in ea ch met hod, as des cri bed abo ve. the re su lt of the inver se dis tan ce weig hti ng met hod is shown in fi gu re 6. it in di ca tes the real po ro si ty dis tri bu tion in the reser voir and is al so si mi lar to the kri gi ng map (fi gu re 7) whi ch is con si de red as the mo st aut hen tic al go rit hm in the sen se of geo lo gy and geomat he ma ti cs. howe ver, the ma ps ob tai ned by the ot her two met ho ds, whi ch are not exa ct in ter po la to rs, are inap prop ria te. the se are mo vi ng ave ra ge (fi gu re 8) and nea re st neig hbour hood (fi gu re 9) ma ps, whe re the pre sen ted iso po ro si ty sha pes can not be mea nin gful ly in ter pre ted. even if the ra dii of the sear chi ng el lip soid is chan ged (mo vi ng ave ra ge), the gra dual tran si tion amo ng li nes has not been ac hie ved. the nea re st neighbour hood re su lt stron gly em pha sises the po lygo nal pre sen tation. the re fo re, the se two met ho ds can not be ap plied to po rosi ty in ter po la tion in re ser voi rs of the 1st san dsto ne se ries. kri gi ng and in ver se dis tan ce weig hti ng met ho ds are pro ven as va lid for po ro si ty map pi ng. this al so re sul ted from the fa ct that the san dsto ne re ser voi rs are a spe cial fa vou rab le lit ho lo gy for the ap pli ca tion of geos ta tis ti cal in ter po la tion met ho ds. this ana lysis al so con fi r ms that the po ro si ty dis tribu tion in re ser voir »t« of lower pon tian age is mo st ap propria tely repre sen ted by the kri gi ng re sul ts. the fi r st eva lua tion is ba sed on the geo lo gi cal mea ni ng of iso po ro si ty li ne sha pes whe re the kri gi ng map des cri bes the po ro si ty dis tri bu tion in the cen tral and eas te rn par ts of the fi e ld par ti cu lar ly we ll. nu me ri cal es ti ma tion of ma ps is per for med usi ng a cro ssva li da tion equa tion. the fol lowi ng va lues were ob tai ned for the dif fe re nt met ho ds (star ti ng wi th the lowe st er ro r): 1. kri gi ng 366.93 (exa ct in ter po la tor) 2. mo vi ng ave ra ge 369.26 (sim ple mat rix smoot hi ng) 3. in ver se dis tan ce weig hti ng 371.97 (exa ct in ter po la tor) 4. nea re st neig hbour hood 389.00 (zo nal as sig nme nt) 04 balic.indd 3204 balic.indd 32 24.6.2008 11:08:2924.6.2008 11:08:29 geologia croatica 33 da vo rin balić et al.: se lec tion of the mo st ap prop ria te in ter po la tion met hod for san dsto ne re ser voi rs in the kloš tar oil and gas fi e ld dif fe ren ces are re la ti ve ly sma ll, but al so show the mi nimum that cha rac te ri ses the kri gi ng re sul ts. it is par tly sur prisi ng that er ro rs ob tai ned by the mo vi ng ave ra ge and nea re st neig hbour hood met ho ds we re not hig her, es pe cial ly when com paring by map grap hi cs whe re il lo gi cal iso po ro si ty sha pes are clear ly vi sib le. it is pro bab ly a re su lt of the re la ti ve ly li mited in put da ta set, whi ch can not refl e ct the true ad van ta ge of using exa ct in ter po la to rs. howe ver, the re is no dou bt that the main er ror is con nected wi th the in te r-we ll area, and not for ad di tio nal es ti ma tion that cou ld be do ne af ter mo vi ng-a nd-es ti ma ti ng va lues at existi ng lo ca tio ns. mo reo ver, cro ss-va li da tion re sul ts ve ry clear ly in di ca ted es ti ma tion dif fe ren ces at par ti cu lar wel ls. the se are two wel ls lo ca ted at the fi e ld mar gin, whi ch is al so why su ch re sul ts cou ld be expec ted. on the re le va nt po ro si ty ma ps the se va lues and wel ls are: · the mo st un de res ti ma ted da ta is lo ca ted at the we ll cir cled in yel low in fi gu re 7 (mea su red va lue is 13.8; es ti ma ted 8.96), · the mo st ove res ti ma ted da ta is lo ca ted at the we ll cir cled in red in fi gu re 7 (mea su red va lue is 5.45; es tima ted 14.56). the other two met ho ds did not pro du ce use ful re sul ts, and the dif fe ren ces in cro ss-va li da tion we re not considered. in fa ct, any »clas sic« in ter po la tion met ho ds can not (es pecial ly in a li mi ted da ta set) repre se nt the true na tu re of the in te rwe ll area. this is the fi e ld of stoc has tic si mu la tio ns that we re not ap plied in this ca se. mo reo ver, the main dif fe ren ce be tween the re sul ts ob tai ned can be explained in ter ms of the exa ct in terpo la tor (the al go rit hms whi ch ho nour the ori gi nal va lues in lo ca tio ns bei ng coin ci dental wi th grid poin ts). su ch in ter po lato rs are the kri gi ng and in ver se dis tan ce weig hti ng met ho ds. the nea re st neig hbour hood met hod is not one of es ti ma tion then as sig nme nt, and the movi ng ave ra ge is rat her a mat rixsmoot hi ng met hod, not an in ter po la tor (jános gei ger, 2007 pe rs. co mm.). this is why cro ss-va li da tion can be used for com pa ri ng dif fe re nt al go rit hms that ha ve the sa me phi lo sop hy (i.e. exa ct or not exa ct in ter po la to rs). in su ch a way, this met hod refl ec ts the sta bi li ty of in ter po la tion. al ter na ti ve ly, the »good ne ss« of in ter po la tion may be in ter pre ted as the sca le of the da ta-poi nt-er ror of the in ter pola tion. that is the dif fe ren ce of an ori gi nal da ta-poi nt va lue and one whi ch was es ti ma ted for the sa me lo ca tion from the grid. na tu ral ly, es ti ma tio ns try to mi ni mi ze this ki nd of er ror fi gu re 6: po ro si ty map in ter po la ted by in ver se dis tan ce weig hti ng fi gu re 7: po ro si ty map in ter po la ted by kri gi ng (isot ro pic va riog ram mo del, ran ge 1100 m) fi gu re 8: po ro si ty map in ter po la ted by the movi ng ave ra ge fi gu re 9: po ro si ty map in ter po la ted by the nea re st neig hbour hood 04 balic.indd 3304 balic.indd 33 24.6.2008 11:08:3024.6.2008 11:08:30 geologia croatica geologia croatica 61/1 34 and pro du ce a gaus sia n-er ror dis tri bu tion. it in clu des the fa ct that the mean er ror is for ced to be clo se to 0, whi le the standa rd de via tion is about 1. howe ver, at the we ll-lo ca tio ns the se er ro rs are dif fe re nt. the bet ter the es ti ma tion, the smal ler the er ror in a par ti cu lar da ta poi nt. grid di ng of the se poi nt er ror is al so wor th thin ki ng about. this is al so why re si dua ls are com pu ted by the sur fer op tion. it gi ves a quan ti ta ti ve mea su re of how es ti ma tion on the grid ag rees wi th the ori gi nal da ta. re si dual va lues are re por ted as eit her po si ti ve or ne ga ti ve va lues (fi gu re 10). sur fer au to ma ti cal ly uses the nea re st neig hbour hood algo rit hm to cal cu la te re si dua ls, i.e. dif fe ren ces be tween mea su red and es ti ma ted va lues in ana lysed san dsto ne re ser voir. it is clear ly seen that su ch dif fe ren ces mos tly nowhe re reac hed ± 2% of po ro si ty, which ma kes the de fau lt re si dual map (fi gu re 10) com ple te ly ac cep tab le for eva lua tion of the mo st sen si ti ve areas for in ter po la tion. the sou th-wes te rn mar gin of the fi e ld is su ch an area, (fi gu re 10, re si dual va lue >13%), pre vious ly des cri bed as an area whe re kri gi ng de fi ned the mo st un de res ti ma ted and ove res ti ma ted va lues. al so, the hi gh ne ga ti ve re si dual (< –8%) is map ped at the sa me cor ner of the fi e ld. 7. conclusions the es ti ma tio ns for re ser voir »t«, (1st san dsto ne se ries of lower pon tian age) in the kloš tar fi e ld, are shown on the ma ps and by the cro ss-va li da tion re sul ts. four in ter po la tion met ho ds we re used – in ver se dis tan ce weig hti ng, nea re st neighbour hood, mo vi ng ave ra ge and kri gi ng. the num ber of we ll (da ta) was 20. it is con si dered as the mi ni mum da ta in san dstones for the mo del li ng of an in put da ta set by an om ni di rec tional va riog ram. this va riog ram mo del is plan ned to im pro ve when the num ber of in pu ts rea ch 30 va lues (in 2008). the qua li ty of po ro si ty in ter po la tion can be eva lua ted ba sed on two cri te ria. the fi r st, grap hi cal one, in clu des the geo lo gi cal des crip tion of iso po ro si ty li ne sha pes, and al so takes in to con si de ra tion all avai lab le ma ps in ter po la ted unoffi cial ly ear lier by ha nd. the se co nd, nu me ri cal cri te rion rep resen ts the es ti ma tion of in ter pre ta tion qua li ty wi th re gar ds to the amou nt of mean squa re er ror (mse). the com pa ri son of mse can exac tly de ter mi ne how a par ti cu lar met hod is mo re suc ces sful in re pea ted es ti ma tion at exis ti ng lo ca tio ns. in this ana lysis the lowe st mse was ac com pa nied by kri gi ng (366.93), and the hig he st by the nea re st neig hbour hood met hod (389.00). the fi nal de ci sion was ma de usi ng bo th cri te ria. mo reo ver, the two met ho ds des cri bed as exa ct in ter po lato rs (kri gi ng and in ver se dis tan ce weig hti ng) are se lec ted as the mo st ap prop ria te for po ro si ty map pi ng in the ana lysed re ser voi rs. in ad di tion, their com pa ri son is fol lowed by poi nter ror da ta ana lyses, im pro vi ng the »clas si cal« mse cal cu lation. the poi nt-er ror (or re si dual) ma ps re veal the areas whe re es ti ma tion can be des cri bed as mo re at ri sk of bei ng mode rate ly sub dued by met hod er ror. the se areas are the sou thwes te rn mar gin of the fi e ld and one of the we lls lo ca ted in the nor th–we st. the re is a gene ral expec ta tion that geos ta tis ti cal met ho ds (li ke kri gi ng) always lead to bet ter ma ps than mat he ma ti cal ly sim pler met ho ds. the ob tai ned re sul ts con fi rm su ch an assumption and, ba sed on es ti ma tion qua li ty, the mo st ap prop ria te met hod was kri gi ng, fol lowed by in ver se distan ce weig hti ng. the ot her two met ho ds (nea re st neig hbour hood and mo vi ng ave ra ge) did not pro du ce ac cep tab le re sul ts, mos tly be cau se they are not exa ct in ter po la to rs. the mo vi ng ave ra ge pa ra meter, ra dii of sear chi ng cir cle, was adap ted, but re sul ts we re not im pro ved. it re mains ju st a mat rix smoot hi ng tool. the nea re st neig hbour hood re sul ts we re ref lec ted throu gh zo nes that can not be con si de red as a geo lo gi cal ly ac cep tab le map, but on ly a sche ma tic view of po ro si ty dis tri bu tion ac cep tab le for qui ck in sig ht. acknowledgement this wo rk rep re sen ts pa rt of the dip lo ma the sis of mr. da vo rin balić, su per vi sed by prof. jo si pa velić and dr. to mis lav malvić. this the sis was pa rt of a mul ti dis cip li na ry geos ta tis ti cal re sear ch pro je ct that was per for med in 2007 wit hin the pro jec ts en tit led: – »stra tig rap hi cal and geo mat he ma ti cal re sear ches of pet roleum geo lo gi cal syste ms in croa tia« (pro je ct no. 1951951293-0237), fi nan ced by the mi nis try of scien ce, edu cation and spor ts of the re pub lic of croa tia; – »impro ve men ts of geo lo gi cal in ter pre ta tion met ho ds wi th pur po se of re co ve ry in crea si ng in san dsto ne re ser voi rs«, fi nanced by ina – oil com pa ny plc. we wou ld li ke to tha nk to. ma rio weis ser m.sc, di rec tor of re ser voir en gi nee ri ng and fie ld de ve lop me nt de par tme nt (as a pa rt of ina – oil in dus try plc.) for per mis sion to pre pa re da ta from the ar chi ve of the de par tme nt for re sear chi ng and pub li sh re sul ts in the dip lo ma the sis. of cour se, than ks to our re viewe rs who of fered a lot of ve ry use ful sug ges tio ns and hig hly im pro ved this pa per. prof. bru no saftić (from uni ver si ty of zag reb) helped us to exte nd the stra tig rap hic re view of the wi der area of the kloš tar fi e ld. prof. jános gei ger (from uni ver si ty of sze ged) hig hly im pro ved the con clu sio ns about the exa ct in ter po la to rs and in di ca ted the ne ces si ty of ap plying poi nt-er ror ana lysis. fi gu re 10: re si dua ls cal cu la ted for par ti cu lar wel ls 04 balic.indd 3404 balic.indd 34 24.6.2008 11:08:3524.6.2008 11:08:35 geologia croatica 35 da vo rin balić et al.: se lec tion of the mo st ap prop ria te in ter po la tion met hod for san dsto ne re ser voi rs in the kloš tar oil and gas fi e ld 8. references aksin, v. (1967): geo lo gi ja naf te. – dnev nik, 800 p. cvetković, m. (2007). naf tno geo loš ka prim je na neu ron skih mre ža na prim je ru le žiš ta po lja kloš tar [pet ro leum geo lo gy use of neu ral ne twor ks on the exam ple of re ser voir in kloš tar fi e ld – in croa tian]. – un pub lis hed gra dua te the sis, fa cul ty of mi ni ng, geo lo gy and pet ro leum en gi nee ri ng, uni ver si ty of zag reb, 49 p. davis, b. (1987): uses and abu ses of cro ss va li da tion in geos ta tis ti cs. – mat he ma ti cal geo lo gy, 19/3, 241–248. hernitz, z., bokor, n. & malvić, t. (2001): geos ta tis ti cal mo deli ng of pet rop hysi cal da ta of oil fi el ds in the nor the rn croa tia. – eage, 63rd con fe ren ce & tec hni cal exhi bi tion, ju ne 11–15 2001, am ster dam, ab stra ct no. p611, 4p. hohn, m.e. (1988): geos ta tis ti cs and pet ro leum geo lo gy. – van nostra nd rein ho ld, 264 p. isaaks, e. & srivastava, r. (1989): an in tro duc tion to ap plied geos ta tis ti cs. – oxfo rd uni ver si ty pre ss inc., 580 p. jensen, j.l., lake, l.w., corbett, p.w.m. & goggin, d.j. (1997): sta tis ti cs for pet ro leum en gi nee rs and geos cien tis ts. – prenti ce ha ll ptr, 390 p. journel, a.g. & huijbregts, c.j. (1978): mi ni ng geos ta tis ti cs. – aca de mic pre ss, 600 p. jüttner, i., saftić, b. & velić, j. (2001): dis tri bu tion of po ro si ty and per mea bi li ty wit hin the pon tian san dsto nes in the wes te rn pa rt of sa va dep res sion in re la tion to their stra tig rap hic ar chi te cture and pa laeo tec tonic re la tio ns. – in: hernitz, z. & sečen, j. (e ds.): spe cial issue of naf ta jour nal dedi ca ted to 2nd in ter na tio nal sympo sium on pet ro leum geo lo gy he ld in 22–24 ap ril 1999, zagreb, croa tia, 139–144. krige, d.g. (1951): a sta tis ti cal ap proa ch to so me ba sic mi ne va luation prob le ms on the wi twa ter sra nd. – jour nal of the che mi cal, metal lur gi cal and mi ni ng so cie ty of sou th af ri ca, 52, 119–139. malvić, t. (2003): one-di men sio nal va riog ram and sta tis ti cal ana lysis in re ser voir uni ts of the bje lo var sag, croa tia. – naf ta, 54/7–8, 267– 274. malvić, t. (2005): resul ts of geos ta tis ti cal po ro si ty map pi ng in wes te rn dra va dep res sion fi el ds (mol ve, ka li no vac, sta ri gra dac). – naf ta, 56/12, 465–476. malvić, t. & đureković, m. (2003): ap pli ca tion of met ho ds: in verse dis tan ce weig hti ng, or di na ry kri gi ng and col lo ca ted cok ri gi ng in po ro si ty eva lua tion, and com pa ri son of re sul ts of the be ni čan ci and sta ri gra dac fi el ds in croa tia. – naf ta, 54/9, 331–340. pamić, j., krkalo, e. & prohić., e. (1984): granitne stijene sjeverozapadnog dijela moslavačke gore u sjevernoj hrvatskoj [granite rocks of the north-western part of moslavačka mt. in the northern croatia – in croatian]. – geologija, 27, 201–212. pletikapić, ž. (1969): stratigrafi ja, paleogeografi ja i naftoplinonosnost ivanić-grad formacije na obodu moslavačkog masiva [stratigraphy, palaeogeography and oil and gas potential of the formation ivanić-grad at the margin of moslavina massive – in croatian]. – faculty of mining, geology and petroleum engineering, university of zagreb, 71 p. saftić, b. (1998): genetska stratigrafska sekvencijska analiza u pontskim naslagama zapadnoga dijela savske depresije [genetic stratigraphic sequential analysis in sediments of pontian sediments of the western part of the sava depression – in croatian]. – unpublished phd thesis, faculty of mining, geology and petroleum engineering, university of zagreb, 136 p. saftić, b., peh, z., velić, j. & jüttner, i. (2001): interdependence of petrophysical properties and depth: some implications of multivariate solution on distinction between the lower pontian hydrocarbon-bearing sandstone units in the western part of the sava depression. – geol. croatica, 54/2, 259–277. velić, j. (1979): o razlikovanju neotektonskih struktura u zapadnom dijelu savske depresije [about distinguishing of neotectonic structures in the western part of the sava depression – in croatian]. – geol. vjesnik, 31, 175–183. velić, j. (1980): geološka građa zapadnog dijela savske depresije [geological settings of the western part of the sava depression– in croatian]. – unpublished phd thesis, faculty of mining, geology and petroleum engineering, university of zagreb, 137 p. velić, j. (1983): neotektonski odnosi i razvitak zapadnog dijela savske potoline [neotectonic relations and evolution of the western part of the sava depression – in croatian]. – acta geologica, 13/2, 26–65. velić, j. & saftić, b. (2000): hydrocarbons in croatia. – vijesti hrvatskoga geološkog društva, 37/2, 42–43. vragović, m. & majer, v. (1980): prilozi za poznavanje metamorfnih stijena zagrebačke gore, moslavačke gore i papuka (hrvatska) [contributions for knowing of metamorphic rocks of the zagreb mt. – in croatian]. – geol. vjesnik, 31, 295–308. manuscript received october 1, 2007. revised manuscipt accepted january 18, 2008. 04 balic.indd 3504 balic.indd 35 24.6.2008 11:08:3724.6.2008 11:08:37 04 balic.indd 3604 balic.indd 36 24.6.2008 11:08:3724.6.2008 11:08:37 in memoriam fluegel.indd on april 14, 2004, 8 days after his 70th birthday, prof. dr. erik flügel has died. we lost not only the founder of the institute of paleontology of the university erlangen–nuremberg, but also an internationally renowned and highly regarded scientist. he was a passionate researcher, ardent teacher, unrelenting science manager, but also a loyal and encouraging colleague and a reliable friend. erik flügel was born on april 6, 1934 in steiermark, austria. from 1940 to 1952 he attended the primary and secondary school at graz where he earned his “abitur”. in 1952 he commenced his studies of geology and paleontology as well as mineralogy and petrography at the universities of graz and marburg, and completed his degree in july 1957 in graz with a phd thesis dealing with the revision of devonian hydrozoans of the graz area. until 1962 he worked at the natural history museum in vienna where he completed his post-doctorate in paleontology. from 1962 on erik flügel worked as “wissenschaftlicher rat” at the technical university of darmstadt, germany, where he became a professor in 1968. in 1971 he extended his venia legendi to include geology. since 1972 he chaired the newly formed institute of palaeontology at the university of erlangen–nuremberg, which he led until his retirement in 1999. during the years erik flügel managed to build up the palaeontology department of erlangen to an internationally renowned research institution. in particular, his name and the name of his institute are tightly connected to the term “microfacies analysis”, a comparative examination of ancient biotic and depositional systems with modern ecosystems. since 1973, he organized and taught interuniversity courses on the topic of facies analyses and facies models in carbonates that were attended throughout the years by more than 1500 persons from universities and the oil and gas industry. in addition, these famous facies courses were taught at different universities in europe and beyond. a further milestone was the foundation of the facies journal, which erik flügel together with his wife, erentraud flügel-kahler, developed over the years from an institutional forum for the publication of larger elaborates to a highly regarded international, interdisciplinary journal. until the year 2003, a total of 553 scientific papers were published in 49 volumes of facies under the editorship of erik flügel and his wife. the study of ancient and modern reefs always were an important focus of erik flügel’s diverse research activities, and his work provided an important contribution to the development of palaeontology as a link between geological and biological sciences. within this geologia croatica 57/2 209–219 zagreb 2004 in memoriam prof. dr. erik flügel 1934–2004 professor erik flügel, a distinguished scientist and a great man, was a member of the international scientific advisory board of geologia croatica since its foundation in 1992. this in memoriam is a slightly modified reprint from facies (2004), 50, 149–159. erik flügel’s support for geologia croatica was of incalculable value to us all, but such largesse was typical of this man who will be sorely missed by all who were privileged to know him... the editors and the editorial board of geologia croatica 210 geologia croatica 57/2 211in memoriam – prof. dr. erik flügel scope, he was organizer and co-ordinator of the priority research programme “global and regional controls of biogenic sedimentation: reef evolution and cretaceous sedimentation” funded by the deutsche forschungsgemeinschaft (dfg) during 1990–1996. his broad research interests are reflected in more than 200 publications and books on topics covering different areas of general and applied palaeontology, palaeoecology, facies analysis, microfacies, reef evolution, and archeometry. his book “fossil algae”, published in 1977, represents results of the “international symposium on fossil algae”, which was founded by flügel in 1975, and continues to date. the book “mikrofazielle untersuchungsmethoden von kalken”, published in 1978, and the english edition “microfacies analysis of limestones”, published in 1982, are further milestone contributions by erik flügel. in 2002, the book “phanerozoic reef patterns” co-edited by erik flügel together with his colleagues wolfgang kiessling and jan golonka, was published as sepm special publication volume 72. it contains a compilation of contributions on reef development in the phanerozoic. his book “microfacies of carbonate rocks – analysis, interpretation, application” was his last large completed oeuvre. unfortunately, he was not destined to witness the publication of this impressive volume recently published in july 2004. because of his remarkable initiative, he was active in numerous national and international organisations. from 1976–1982 he was a member of the “wissenschaftlicher beirat am bayerischen staatsministerium für kultur und unterricht”. for many years (1980–1988) he acted as main-referee for palaeontology for the dfg. he led the steering committee of the “sciences of the solid earth”, and from 1991 to 1999 he was a member of the “senatskommission für geowissenschaftliche gemeinschaftsforschung” of the dfg. in addition, he was corresponding member of the austrian academy of science since 1992. from 1995 to 1999, he joined the scientific advisor committee of the alfredwegener-institut für polarund meeresforschung in bremerhaven. since 1996, erik flügel led the scientific advisory panel of the forschungsinstitut senckenberg, frankfurt. in recognition of his earnings, erik flügel was awarded with numerous honours. in 1985, he received the “hans-stille-award” of the deutsche geologische gesellschaft, in 1998 the honorary doctorate (dr. h.c.) of the free university of berlin, and in march 2000 the “gustav-steinmann-medal” of the geologische vereinigung. since 2002, he was honorary fellow of the geological society of america. his main motivation was always driven by the urge to stimulate the progress of science and to encourage promising young scientists. an astonishing number of erik flügel’s former students are now holding professorships all over germany. despite his great scientific achievements, he never put his personality before his goals. in his charming and integrative manner, he showed great skills in teaming-up scientists covering many disciplines to form competitive research groups. in that way, he was of invaluable help as scientific advisor of many leading institutions and organizations. his death came much too early and means a substantial loss for palaeontology, which, as a discipline, is under severe pressure these days regarding institutional re-organisation nationwide. the scientific community will miss his voice and his fascinating ability to foresee future developments. we have lost one of our strongest advocates. andré freiwald institute of paleontology, university of erlangen-nuremberg, loewenichstr. 28, 91054 erlangen, germany e-mail: andre.freiwald@pal.uni-erlangen.de 210 geologia croatica 57/2 211in memoriam – prof. dr. erik flügel flügel, h. & flügel, e. (1953): geschichte, ausdehnung und produktion der blei-zink-abbaue des grazer paläozoikums. iv. besitzverhältnisse, zusammenfassung und schluß.– berg. hüttenmänn. mh., 98/10, 211–218, 4 figs., leoben. flügel, e. (1954): johann nepomuk heipl. ein steirischer gewerke des 18. jahrhunderts.– n. chron. gesch. volkskd. innerösterr. alpenl., 21, 3–4, graz. flügel, e. (1955): bonaparte in graz.– bl. heimatkd., 20, 114–121, hist. verein steiermark, graz. flügel, e. (1956): zur bibliographie der stromatoporen.– mitt. naturwiss. ver. steiermark, 86, 26–31, graz. flügel, e. (1956): revision der devonischen hydrozoen der karnischen alpen.– carinthia ii, 66, 41–60, 1 pl., klagenfurt. flügel, e. (1957): über die taxionomischen merkmale und die artdiagnose bei stromatoporen.– n. jb. geol. paläont. mh., 1957/3, 97–108, 3 figs., stuttgart. flügel, e. (1957): neuaufnahmen im grazer paläozoikum 1955/56.1. der hochschlagstock östlich von st. erhard (breitenau).– anz. österr. akad. wiss., math.-naturwiss. kl., 1957/7, 113–115, wien. flügel, e. (1957): steirischer bergbau vor 200 jahren. ein querschnitt durch die steirische bergbaugeschichte des 18. jahrhunderts.– bl. heimatkd., 31/4, 115–122, graz. flügel, e. (1958): revision der hydrozoen des grazer devons.– mitt. geol. ges. wien, jg. 1956, 49, 129–172, 6 pls., 4 figs., wien. flügel, e. (1958): artenrevision von actinostroma nicholson (stromatoporoidea).– anz. österr. akad. wiss., math.naturwiss. kl., 1958/4, 25–29, wien. flügel, e. (1958): die paläozoischen stromatoporen-faunen der ostalpen. verbreitung und stratigraphie.– jb. geol. bundesanst., 101/1, 167–186, 1 fig., 4 tabs., wien. flügel, e. (1958): pseudoactinodictyon n. gen. und actinodictyon parks (stromatoporoidea).– senck. leth., 39, 3/4, 135–151, 2 pls., 1 fig., frankfurt. flügel, e. (1958): stromatopora tornquisti deninger, der genotypus von stromatoporina kühn (hydrozoa).– anz. österr. akad. wiss., math.-naturwiss. kl., 1958/12, 1–8, wien. flügel, e. (1958): eine mitteldevonische korallen-stromatoporen-fauna vom plöcken-paß (kleiner pal-westflanke, karnische alpen).– carinthia ii, 68, 49–61, klagenfurt. flügel, e. (1958): eisenerzbergbau am plankogel. notizen zur bergbaugeschichte der nordoststeiermark.– weiz. gesch. landschaft einzeldarst., 5/1, 67–71, 1 fig., weiz. flügel, e. (1958): fossile hydrozoen – eine wenig bekannte gruppe riffbildender meerestiere.– veröff. naturhist. mus. wien, n. f., 1, 27–32, 7 figs., wien. flügel, e. (1959): stromactinia vinassa de regny und sphaerocodium rothpletz (algae; trias).– anz. österr. akad. wiss., math.-naturwiss. kl., 1959/4, 36–46, wien. flügel, e. & gräf, w. (1959): aufnahmen 1958 auf kartenblatt kötschach (197).– verh. geol. bundesanst., 1959/3, 17–19, wien. flügel, e. & sy, e. (1959): die hydrozoen der trias.– n. jb. geol. paläont. abh., 109/1, 1–108, pls. 1–3, 2 figs., stuttgart. flügel, e. & gräf, w. (1959): ein neuer fund von asterocalamites scrobiculatus (schloth.) zeiller im hochwipfelkarbon der karnischen alpen.– carinthia ii, 69, 41–42, klagenfurt. flügel, e. (1959): statement concerning the types and figured originals from the collections of the novarra expedition in the custody of the geological-paleontological section of the museum of natural history, vienna, austria.– new zealand j. geol. geophysics, 2/5, 826–843, lower hutt. flügel, e. (1959): hydrozoen aus dem oberen perm von slovenija und crna gora.– geologija, 5, 86–91, 1 pl., ljubljana. flügel, e. (1959): die gattung actinostroma nicholson und ihre arten (stromatoporoidea).– ann. naturhist. mus. wien, 63, 90–273, 2 pls., 3 figs., 27 tabs., wien. flügel, e. (1960): cassianostroma n. gen., die erste hydrozoe aus den cassianer schichten (ober-ladin) der südalpen.– n. jb. geol. paläont. mh., 1960/2, 49–59, 5 figs., stuttgart. flügel, e. (1960): actinostromaria cantabrica schnorfsteiner (hydrozoa) aus der unterkreide (aptium) von südbulgarien.– geologie, 9/1, 80–83, 2 figs., berlin. flügel, e. (1960): heterastridium conglobatum conglobatum reuss, an upper triassic hydrozoa from the petra-touroumiou limestone of pendakomo, cyprus.– j. paleont., 34/1, 127–132, pl. 26, tulsa. flügel, e. (1960): solenoporaceen (algae) aus den zlambach-schichten (rhät) der fischerwiese bei alt-aussee, steiermark.– n. jb. geol. paläont. mh., 1960/8, 339–354, 3 figs., stuttgart. flügel, e. (1960): nichtmarine muscheln aus dem jungpaläozoikum von zöbing (niederösterreich).– verh. geol. bundesanst., 1960/1, 78–82, wien. flügel, e. & gräf, w. (1960): aufnahmen 1959 auf kartenblatt kötschach (197), karnische alpen.– verh. geol. bundesanst., 1960/3, 20–22, wien. flügel, e. & zapfe, h. (1960): aufnahmearbeiten im gebiet des gosaukammes unter besonderer berücksichtigung stratigraphischer fragen.– verh. geol. bundesanst., 1960/3, 83, wien. flügel, e. (1960): untersuchungen im obertriadischen riff des gosaukammes (dachsteingebiet, oberösterreich). ii. untersuchungen über die fauna und flora des dachsteinriffkalkes der donnerkogelgruppe.– verh. geol. bundesanst., 1960/2, 241–252, wien. flügel, e. (1960): riffbildende tiere und pflanzen aus der obertrias der nordalpen.– veröff. naturhist. mus., n. f., 3, 16–20, 8 figs., wien. erik flügel – scientific contributions 212 geologia croatica 57/2 213in memoriam – prof. dr. erik flügel flügel, e. (1961): gattungsliste der fossilen hydrozoen.– n. jb. geol. paläont. abh., 113/1, 68–94, stuttgart. flügel, e. & ramovs, a. (1961): fossilinhalt und mikrofazies des dachsteinkalkes (ober-trias) im begunjscica gebirge, s-karawanken (nw-slowenien, jugoslawien).– n. jb. geol. paläont. mh., 1961/6, 287–294, stuttgart. flügel, e. & zapfe, h. (1961): stratigraphischpaläontologische aufnahmearbeiten am w-ende des gosaukammes (oberösterreich).– verh. geol. bundesanst., 1961/3, 28, wien. flügel, e. (1961): eine koralle aus dem schwarzen sturiakalk (anis) des tretto (vicentin).– verh. geol. bundesanst., 1961/1, 80–83, 2 figs., wien. flügel, e. & bachmayer, f. (1961): die hydrozoen aus dem ober-jura von ernstbrunn (niederösterreich) und stramberg (csr).– palaeontographica, a, 116, 5/6, 122–143, pls. 15–18, 6 figs., 1 tab., stuttgart. flügel, e. & bachmayer, f. (1961): die “chaetetiden” aus dem ober-jura von ernstbrunn (niederösterreich) und stramberg (csr).– palaeontographica, a, 116, 5/6, 144–174, pls. 19–26, 10 figs., 1 tab., stuttgart. flügel, e. (1961): algen (solenoporaceen) aus den cassianer-schichten (ober-ladin) der südalpen.– n. jb. geol. paläont. mh., 1961/7, 339–345, 4 figs., stuttgart. flügel, e. (1961): vorläufiger bericht über den fossilinhalt der sauwand (ober-trias) bei gußwerk, steiermark.– mitt. naturwiss. ver. steiermark, 91, 31–36, graz. flügel, e. (1961): typen-katalog. verzeichnis der in der geol.-paläont. abteilung des naturhistorischen museums in wien aufbewahrten typen sowie der abbildungsoriginale. 1. protozoa und coelenterata.– ann. naturhist. mus. wien, 64, jg. 1960, 65–104, wien. flügel, h. & flügel, e. (1961): zur paläontologie des anatolischen paläozoikums. vii. stromatoporen und korallen aus dem mittel-devon von feke (anti-taurus).– senck. leth., 42, 5/6, 377–409, 4 pls., frankfurt flügel, e. (1961): bryozoen aus den zlambach-schichten (rhät) des salzkammergutes, österreich.– sitzber. österr. akad. wiss., math.-naturwiss. kl., i, 170, 5/6, 265–277, pls. 1–3, 3 figs., wien. flügel, e. (1962): untersuchungen im obertriadischen riff des gosaukammes (dachsteingebiet, oberösterreich). iii. zur mikrofazies der zlambach-schichten am w-ende des gosaukammes.– verh. geol. bundesanst., 1962/1, 138–145, pl. 5, 1 fig., wien. flügel, e. & kirchmayer, m. (1962): zur terminologie der ooide, onkoide und pseudooide.– n. jb. geol. paläont. mh., 1962/3, 113–123, 2 figs., 2 tabs., stuttgart. flügel, e. (1962): neue spongien und algen aus den zlambach-schichten (rhät) des westlichen gosaukammes.– ann. naturhist. mus. wien, 65, jg. 1961, 51–56, 2 pls., wien. flügel, e. (1962): der biostratigraphische wert der stromatoporen im silur und devon.– 2. internationale arbeitstagung über die silur/devon-grenze und die stratigraphie von silur und devon, bonn-bruxelles, 1960, symposiums-band, 80–86, schweizerbart, stuttgart. flügel, e. (1962): ökologisch-stratigraphische untersuchungen in den obertriadischen riffbildungen der nordalpen.– geologija, 8, 265–267, ljubljana. flügel, e. (1963): zur mikrofazies der alpinen trias.– jb. geol. bundesanst., 106, 205–228, pls. 1–3, 2 figs., 2 tabs., wien. flügel, e. & flügel-kahler, e. (1963): mikrofazielle und geochemische gliederung eines obertriadischen riffes der nördlichen kalkalpen (sauwand bei gußwerk, steiermark, österreich).– mitt. mus. bergbau geol. technik, landesmus. joanneum graz, jg. 1962, 1–128, 10 pls., 11 figs., 19 tabs., graz. flügel, e. & kirchmayer, m. (1963): typlokalität und mikrofazies des gutensteiner kalkes (anis) der nordalpinen trias.– mitt. naturwiss. ver. steiermark, 93, 106–136, pls. 8–13, 7 figs., 4 tabs., graz. flügel, e. (1963): zur geologie der sauwand bei gußwerk (steiermark).– mitt. naturwiss. ver. steiermark, 93, 64– 105, pls. 3–7, 4 figs., 8 tabs., graz. flügel, e. (1963): oberdevonische stromatoporen aus der bohrung münsterland 1.– fortschr. geol. rheinland westfalen, 11, 329–342, 2 pls., 2 tabs., krefeld. flügel, e. (1963): revision der triadischen bryozoen und tabulaten.– sitzber. österr. akad. wiss., math.-naturwiss. kl., 172, 6/8, 225–252, 3 tabs., wien. flügel, e. (1964): mikroproblematika aus den rhätischen riffkalken der nordalpen.– paläont. z., 38, 1/2, 74–87, pls. 8–9, 1 fig., 1 tab., stuttgart. flügel, e. (1964): ein neues vorkommen von plassenkalk (ober-jura) im steirischen salzkammergut, österreich.– n. jb. geol. paläont. abh., 120/2, 213–232, pls. 11–13, 2 figs., 1 tab., stuttgart. flügel, e. (1964): über die beziehungen zwischen stylophyllopsis frech, oppelismilia duncan und molukkia jaworski (scleractinia, trias–lias).– n. jb. geol. paläont. mh., 1964/6, 336–348, 4 figs., 1 tab., stuttgart. flügel, e. & hötzl, h. (1966): hydrozoen aus dem oberjura der hesperischen ketten (ost-spanien).– n. jb. geol. paläont. abh., 124/2, 103–117, pls. 15–18, stuttgart. flügel, e. (1966): mitteljurassische korallen vom ostrand der großen salzwüste (shotori-kette, iran).– n. jb. geol. paläont. abh., 126/1, 46–91, pls. 15–19, 3 figs., 6 tabs., stuttgart. flügel, e. (1966): algen aus dem perm der karnischen alpen.– carinthia ii, sonderheft, 25, 76 p., 11 pls., 15 figs., 12 tabs., klagenfurt. flügel, e. (1967): conodonten und mikrofazies der hallstätter kalke (nor) am siriuskogel in bad ischl, oberösterreich.– n. jb. geol. paläont. mh., 1967/2, 91–103, 2 tabs., stuttgart. flügel, e. (1967): elektronenmikroskopische untersuchungen an mikritischen kalken.– geol. rundschau, 56, 341– 358, 2 pls., 2 figs., 1 tab., stuttgart. flügel, e. (1967): eine neue foraminifere aus den riffkalken der nordalpinen ober-trias: alpinophragmium perforatum n. g., n. sp.– senck. leth., 48/5, 331–402, pls. 1–2, 8 figs., frankfurt. 212 geologia croatica 57/2 213in memoriam – prof. dr. erik flügel flügel, e. (1967): elektronenmikroskopischer nachweis von coccolithen im solnhofener plattenkalk (oberjura).– n. jb. geol. paläont. abh., 127/3, 245–263, pls. 24–26, 1 fig., 1 tab., stuttgart. flügel, e. & franz, h.e. (1967): über die lithogenetische bedeutung von coccolithen in malmkalken des flachwasserbereiches.– eclogae geol. helvetiae, 60/1, 1–17, 4 pls., 1 fig., 3 tabs., basel. flügel, e. (1968): bericht über fazielle und stratigraphische untersuchungen im perm der karnischen alpen.– carinthia ii, 78, 38–65, 1 fig., 5 tabs., klagenfurt. flügel, e., wolf, k.h. & kemezys, k.k. (1968): ordovician calcareous algae from a bioherm, blathery creek volcanics, new south wales (australia).– rev. palaeobot. palynol., 6, 147–153, 4 figs., amsterdam. flügel, e., franz, h.e. & ott, w.f. (1968): review on electron microscope studies of limestones.– in: friedman, g.m. & müller, g. (eds.): recent developments in carbonate sedimentology in central europe, 85–97, 2 pls., 5 figs., 3 tabs., springer, berlin– heidelberg–new york. flügel, e. & flügel-kahler, e. (1968): stromatoporoidea.– fossilium catalogus, i, animalia, 115/116, 681 p., w. junk, ‘s-gravenhage. flügel, e. & wolf, k.h. (1969): “sphaerocodien” (algen) aus dem devon von deutschland, marokko und australien.– n. jb. geol. paläont. mh., 1969/2, 88–103, 4 figs., 1 tab., stuttgart. flügel, e. (1969): stromatoporen aus dem silur des östlichen iran.– n. jb. geol. paläont. mh., 1969/4, 209–219, 6 figs., stuttgart. flügel, e. (1969): hydrozoa.– catalogus fossilium austriae, iv b, 74 p., österr. akad. wiss., wien. flügel, e. (1969): hydrozoen mit circumlamellarer mikrostruktur aus den gosau-schichten (senon) des gosaubeckens (oberösterreich/salzburg).– verh. geol. bundesanst., 1969/2, 126–131, 1 pl., 1 tab., wien. flügel, e. (1969): fazielle und stratigraphische untersuchungen im perm der karnischen alpen.– carinthia ii, sonderheft, 27, 21–22, klagenfurt . flügel, e. (1970): palökologische interpretation des zottachkopf-profiles mit hilfe von kleinforaminiferen (oberer pseudoschwagerinen-kalk, unteres perm: karnische alpen, österreich).– carinthia ii, kahler-festschrift, 61–96, 4 pls., 3 figs., 2 tabs., klagenfurt. flügel, e. (1970): dasycladaceen aus dem alpinen muschelkalk (anis) des gartnerkofel-gebietes (karnische alpen, kärnten).– anz. österr. akad. wiss., math.-naturwiss. kl., 1970/2, 50–54, 2 tabs., wien. flügel, e. & agiorgitis, g. (1970): rotsedimentation im trogkofel-kalk (höheres unter-perm) der karnischen alpen.– anz. österr. akad. wiss., math.-naturwiss. kl., 1970/9, 1–5, 2 tabs., wien. flügel, e. (1970): corallinaceen (rotalgen) aus dem oberoligozän von pohlkotte bei osnabrück.– jb. naturwiss. ver. osnabrück, 33, 60–70, 3 figs., 3 tabs., osnabrück. flügel, e. & hötzl, h. (1970): über die verwendung von multivarianzanalytischen verfahren bei fazies-untersuchungen.– anz. österr. akad. wiss., math.-naturwiss. kl., 1970/11, 201–211, wien. backhaus, e. & flügel, e. (1971): fazielle und geochemische untersuchungen am unteren muschelkalk des michelstädter grabens (odenwald).– notizbl. hess. landesamt. bodenforschung, 99, 200–213, pl. 15, 2 figs., 5 tabs., wiesbaden. flügel, e. & tietz, g.-f. (1971): über die ursachen der buntfärbung in oberrät-riffkalken (adnet, salzburg).– n. jb. geol. paläont. abh., 139/1, 29–42, 3 figs., 4 tabs., stuttgart. flügel, e. & tietz, g.-f. (1971): red limestones in the kirchbruch quarry, adnet (salzburg).– sedimentology of parts of central europe. guidebook, viii. int. sed. congress, 1971, 187–192, 2 figs., 1 tab., kramer, frankfurt. flügel, e., homann, w. & tietz, g.-f. (1971): litho und biofazies eines detailprofils in den oberen pseudoschwagerinen-schichten (unter-perm) der karnischen alpen.– verh. geol. bundesanst., 1971/1, 10–42, 6 figs., 4 tabs., wien. flügel, e. & hötzl, h. (1971): foraminiferen, calcisphaeren und kalkalgen aus dem schwelmer kalk (givet) von letmathe im sauerland.– n. jb. geol. paläont. abh., 137, 358–395, 6 pls., stuttgart. flügel, e. (1972): mikrofazielle untersuchungen in der alpinen trias: methoden und probleme.– mitt. ges. geol. bergbaustud. österr., 21, 9–64, 9 pls., 1 fig., 5 tabs., innsbruck. flügel, e. (1972): mikroproblematika in dünnschliffen von trias-kalken.– mitt. ges. geol. bergbaustud. österr., 21, 957–988, 2 figs., 2 tabs., innsbruck. flügel, e. & meixner, h. (1972): pyritisierte spongiennadeln und radiolarien aus oberalmer-kalken (malm) des weißenbachtales sw strobl/wolfgangsee (salzburg).– ann. naturhist. mus. wien, 76, 187–194, 2 pls., wien. brinkmann, r., flügel, e., jacobshagen, v., lechner, h., rendel, b. & trick, p. (1972): trias, jura und unterkreide der halbinsel karaburun (west-anatolien).– geologica palaeontologica, 6, 139–150, 4 figs., marburg. flügel, e. (1974): stromatoporen aus dem schwelmer kalk (givet) des sauerlandes.– paläont. z., 48, 3/4, 149–187, pls. 24–27, 9 tabs., stuttgart. flügel, e. (1974): fazies-interpretation der unterpermischen sedimente in den karnischen alpen.– carinthia ii, 84, 43–61, 7 tabs., klagenfurt. buggisch, w., flügel, e. & tietz, g.-f. (1974): mitteldevonische vulkanite im südanatolischen taurus.– n. jb. geol. paläont. mh., 194, 577–592, 4 figs., stuttgart. flügel, e. (1974): fazies-interpretation der cladocoropsiskalke (malm) auf karaburun, w-anatolien.– arch. lagerstforsch. ostalpen, sonderband 2, 79–94, 4 pls., leoben. flügel, e. & kahler, f. (eds.) (1974): forschungsergebnisse im ostund südalpinen perm.– mitt. naturwiss. ver. kärnten, carinthia ii, 7–124, klagenfurt. flügel, e. (1975): fossile hydrozoen–kenntnisstand und probleme.– paläont. z., 49/4, 369–406, 13 figs., 3 tabs., stuttgart. 214 geologia croatica 57/2 215in memoriam – prof. dr. erik flügel flügel, e. (1975): kalkalgen aus riffkomplexen der alpinmediterranen obertrias.– verh. geol. bundesanst., 1974, 2/3, 297–346, 4 pls., 11 figs., wien. fenninger, a., flügel, h.w., flügel, e. & schönlaub, p. (1975): zur variszischen orogenese in den ostalpen – eine stellungnahme.– verh. geol. bundesanst., jg. 1974, a149-a157, wien. flügel, e. & flügel-kahler, e. (1975): stromatoporen aus dem unteren kohlenkalk (tn 1 b, strunium) von aachen.– n. jb. geol. paläont. abh., 149/1, 1–38, 9 pls., 7 figs., stuttgart. flügel, e. (ed.) (1975): guide book, international symposium on fossil algae erlangen.– 228 p., institut für paläontologie, universität erlangen. flügel, e. & haditsch, j.g. (1975): vorkommen hochreiner und reinster kalke im steirischen salzkammergut.– arch. lagerstforsch. ostalpen, 15, 65–83, 6 figs., leoben. flügel, e. (1975): forschungsziele der paläontologie.– universitas, 30/2, 167–172, stuttgart. buggisch, w., flügel, e., leitz, f. & tietz, g.-f. (1976): fazies und paläogeographische entwicklung im perm der karnischen alpen und in den randgebieten.– geol. rundschau, 65/2, 649–690, 19 figs., 4 tabs., stuttgart. flügel, e. & hötzl, h. (1976): paläkologische und statistische untersuchungen in mitteldevonischen schelfkalken (schwelmer kalk, givet: rheinisches schiefergebirge).– abh. bayer. akad. wiss., math.-naturwiss. kl., n. f., 156, 79 p., 29 figs., 17 tabs., münchen. buggisch, w., flügel, e., leitz, f. & tietz, g.-f. (1976): tektonische bewegungen an der wende unter/ mittelperm in den südalpen.– nachr. deutsch. geol. ges., 15, 30, hannover. flügel, e. (ed.) (1977): fossil algae. recent results and developments.– 375 p., 32 pls., 119 figs., springer, berlin–heidelberg–new york. flügel, e. (1977): environmental models for upper paleozoic benthic calcareous algal communities.– in: flügel, e. (ed.): fossil algae. 314–343, 4 pls., 3 figs., 8 tabs., springer, berlin–heidelberg–new york. flügel, e. (1977): untersuchungen über die beziehungen zwischen mikrofaziellen und technologischen merkmalen steirischer dachstein-kalke (obertrias. grimmingstock, gesäuse).– mitt. abt. geol. paläont. landesmus. joanneum, 38, 47–58, 8 figs., graz. flügel, e. (1977): verkalkungsmuster porostromater algen aus dem malm der südlichen frankenalb.– geol. bl. nobayern, 27/3, 131–140, 12 figs., erlangen. flügel, e. (1978): mikrofazielle untersuchungsmethoden von kalken.– 454 p., 33 pls., 68 figs., 57 tabs., springer, berlin–heidelberg–new york. flügel, e. (1978): paläontologische beiträge zur evolution der organismen.– in: siewing, r. (ed.): evolution. 221–262, figs. 89–107, uni-taschenbücher 748, fischer, stuttgart. flügel, e., lein, r. & senowbari-daryan, b. (1978): kalkschwämme, hydrozoen, algen und mikroproblematika aus den cidaris-schichten (karn, ober-trias) der mürztaler alpen (steiermark) und des gosaukammes (oberösterreich).– mitt. ges. geol. bergbaustud. österr., 25, 153–195, 54 figs., 1 tab., wien. buggisch, w., flügel, e., leitz, f. & tietz, g.-f. (1978): paleogeography of the permian in the southern alps.– in: closs, h., roeder, d., schmidt, k. (eds.): alps, apennines, hellenides. inter-union commission on geodynamics, scientific report 38, 108–112, 3 figs., schweizerbart, stuttgart. flügel, e., kahler, f. & kahler, g. (1978): nachweis von marinem mittelperm bei forni avoltri (carnia, südalpen).– n. jb. geol. paläont. mh., 1978, 449–458, 15 figs., 1 tab., stuttgart. flügel, e. (1979): paleoecology and microfacies of permian, triassic and jurassic algal communities of platform and reef carbonates from the alps.– bull. centre rech. explor., 3/2, 569–587, 3 pls., pau. brinkmann, r., flügel, e. & kaya, o. (1979): karbon und trias im östlichen anatolien.– ege üniversitesi fen fakültesi derges, ser. b, cilt iii, sayi 1, 2, 3, 4, 119–124. flügel, e. & keupp, h. (1979): coccolithen-diagenese in malm-kalken (solnhofen/frankenalb, oberalm/salzburg).– geol. rundschau, 68/3, 876–893, 3 pls., 1 fig., 2 tabs., stuttgart. flügel, e. (1979): ptychochaetetiden aus dem oberen malm der südlichen frankenalb.– geol. bl. nobayern, 29/1, 1–11, 7 figs., 1 tab., erlangen. flügel, h. & flügel, e. (1979): tabulata, sclerospongia und stromatopora aus dem devon von menorca.– mitt. österr. geol. ges., 70, 49–73, 6 pls., 1 fig., wien. dürr, st. & flügel, e. (1979): contribution à la stratigraphie du cristallin des cyclades: mise en évidence de trias supérieur dans les marbres de naxos (grèce).– xxve congrès-assemblee plénière, antalya, 1978, comite geologie geophysique marines.– rapportes procès-verbaux réunions c.i.e.s.m., 2 p., monaco. buggisch, w. & flügel, e. (1980): die trogkofelschichten der karnischen alpen: verbreitung, geologische situation und geländebefund.– carinthia ii, sonderheft 36, 13–50, 14 figs., klagenfurt. flügel, e. (1980): die mikrofazies der kalke in den trogkofel-schichten der karnischen alpen.– carinthia ii, sonderheft 36, 51–99, 14 pls., 2 figs., klagenfurt. flügel, e. & flügel-kahler, e. (1980): algen aus den kalken der trogkofel-schichten der karnischen alpen.– carinthia ii, sonderheft 36, 113–182, 14 pls., 1 tab., klagenfurt. buchroithner, m., flügel, e., flügel, h.w. & stattegger, k. (1980): mikrofazies, fossilien und herkunft der kalk-gerölle im karbon-”flysch” der betischen kordilleren, spanien.– facies, 2, 1–54, pls. 1–8, 2 figs., 1 tab., erlangen. buchroithner, m., flügel, e., flügel, h.w. & stattegger, k. (1980): die devongerölle des paläozoischen flysch von menorca und ihre paläogeographische bedeutung.– n. jb. geol. paläont. abh., 159/2, 172–224, 13 figs., 7 tabs., stuttgart. 214 geologia croatica 57/2 215in memoriam – prof. dr. erik flügel flügel, e. (1981): lower permian tubiphytes/archaeolithoporella buildups in the southern alps (austria and italy).– soc. econ. paleont. min., spec. publ., 30, 143–160, 9 figs., tulsa. flügel, e. & steiger, t. (1981): an upper jurassic sponge-algal buildup from the northern frankenalb, west germany.– soc. econ. paleont. min., spec. publ., 30, 371–397, 23 figs., tulsa. flügel, e. (1981): paleoecology and facies of upper triassic reefs in the northern calcareous alps.– soc. econ. paleont. min., spec. publ., 30, 291–359, 26 figs., tulsa. flügel, e. (1981): the permian of the carnic alps – depositional environments and microfacies.– int. symp. central european permian, jablona 1978, 84–94, 5 tabs., warsaw. flügel, e. (1981): “tubiphyten” aus dem fränkischen malm.– geol. bl. no-bayern, 31, 126–142, 12 figs., erlangen. flügel, e. (ed.) (1981): guide book, international symposium on triassic reefs.– 252 p., 64 figs., institut für paläontologie, universität erlangen. flügel, e. & wurm, d. (1981): faziesmodelle im mesozoikum der nordalpen.– exkursionsführer jahrestagung paläont. ges. erlangen 1981, 1–53, 16 figs., erlangen. flügel, e. (1982): microfacies analysis of limestones.– 633 p., 53 pls., 78 figs., 58 tabs., springer, berlin–heidelberg–new york. flügel, e. & mörtl, j. (1982): mitteltriadische dasycladaceen (kalkalgen) sowie permoskyth aus der bohrung k, südlich edling, bezirk völkermarkt, kärnten.– carinthia ii, 92, 97–104, 5 figs., klagenfurt. flügel, e. & mu, x. (1982): upper triassic dasycladaceae from eastern tibet.– facies, 6, 59–74, pls. 8–10, erlangen. flügel, e. (1982): evolution of triassic reefs: current concepts and problems.– facies, 6, 297–328, erlangen. flügel, e. (1983): mikrofazies der pantokrator-kalke (lias) von korfu, griechenland.– facies, 8, 263–300, pls. 41–49, 1 fig., erlangen. harder, h., jacobshagen, v., skala, w., arafeh, m., berndsen, j., hoffmann, a., kusserow, h., schneider, w. & flügel, e. (1983): geologische entwicklung und struktur der insel skyros, nordsporaden, griechenland.– berliner geowiss. abh., reihe a, 48, 7–40, berlin. schlager, w., austin, j.a., corso, w., flügel, e., mcnulty c.l., renz, o. & steinmetz, j.c. (1984): early cretaceous platform re-entrant and escarpment erosion in the bahamas.– geology, 12, 147–150, 3 figs., boulder. flügel, e., ramovs, a. & kochansky-devidé, v. (1984): a middle permian calcisponge/algal/cement reef: straza near bled, slovenia.– facies, 10, 179–256, pls. 24–42, 7 figs., erlangen. flügel, e., flügel-kahler, e., martin, j.m. & martin-algarra, a. (1984): middle triassic reefs from southern spain.– facies, 11, 173–218, pls. 20–30, 7 figs., 2 tabs., erlangen. flügel, e. & stanley, g.d. (1984): reorganization, development and evolution of post-permian reefs and reef organisms.– palaeontographica amer., 54, 177–186, 5 figs., ithaca. flügel, e. (1984): permian reefs: evolution, structure and paleoecology.– in: geister, j. & herb, r. (eds.): geologie et paleoecologie des recifs. 3eme cycle en sciences de la terre, 10.1–10.20, 17 figs., bern. flügel, e. & wurm, d. (1984): triassic reefs: facts and problems.– in: geister j. & herb, r. (eds.): geologie et paleoecologie des recifs. 3eme cycle en sciences de la terre, 11.1.-11.2, bern. flügel, e. (1984): algae in reefs.– in: geister, j. & herb, r. (eds.): geologie et paleoecologie des recifs. 3me cycle en sciences de la terre, 24.1.-24.28, 19 figs., bern. corso, w., schlager, w., buffler, r.t. & flügel, e. (1985): a reinterpretation of an early cretaceous carbonate platform on abaco knoll, northern bahmas.– gulf coast ass. geol. soc. transact., 35, 29–38, 8 figs., houston. flügel, e. (1985): diversity and environment of permian and triassic dasycladacean algae.– in: toomey, d.f. & nitecki, m.h. (eds.): paleoalgology: contemporary research and applications, 344–351, 6 figs., springer, berlin–heidelberg–new york. corso, w., schlager, w., buffler, r.t. & flügel, e. (1985): an early cretaceous reef at abaco knoll, northern bahamas.– in: bebout, d. & ratcliff, f. (eds.): lower cretaceous depositional environments from shoreline to slope. a core workshop. annual meeting gcags-gcs/sepm, austin/texas, 65–69, 3 figs., 1 tab., austin. flügel, e. (1986): zur mikrofazies oberanisischer riffkalke in den östlichen nordkarawanken, kärnten.– carinthia ii, 96, 463–478, 5 pls., klagenfurt. flügel, e. & zhou, z.-c. (1986): carbonate ramp deposition: middle to upper carboniferous microfacies of eastern anhui and southern jiangsu, china.– facies, 14, 201–234, pls. 39–43, 7 figs., erlangen. järvinen, o., babin, c., bambach, r.k., flügel, e., fürsich, f.t., futuyma, d.j., niklas, k.j., panchen, a.l., simberloff, s., underwood, a.j. & weidich, k.f. (1986): the neontologico-paleontological interface of community evolution: how do the pieces in the kaleidoscopic biosphere move?– in: raup, d.m. & jablonski, d. (eds.): patterns and processes in the history of life. life sciences res. rep. 36, dahlem konferenzen, 331–350, springer, berlin. stanton, r.j. & flügel, e. (1987): paleoecology and facies of upper triassic reefs in the northern calcareous alps: reef communities.– facies, 16, 157–186, 9 figs., 3 tabs., erlangen. flügel, e. (1987): reef mound – entstehung: algenmounds im unterperm der karnischen alpen.– facies, 17, 73–90, pls. 7–9, 4 figs., erlangen. flügel, e., dullo, w.chr., lein, r., riedel, p. & senowbari-daryan, b. (1987): algen, kalkschwämme und mikroproblematika aus unterkarnischen 216 geologia croatica 57/2 217in memoriam – prof. dr. erik flügel riffkalken des bosruck-gipfels (nördliche kalkalpen, österreich).– jb. geol. bundesanst., 129, 3/4, 525–543, 4 pls., 4 figs., 2 tabs., wien. flügel, e. & kahler, f. (1988): faziell-stratigraphische entwicklung im paläozoikum von belemedik (“bagdadbahn-profil”), südanatolien.– facies, 18, 123–168, pls. 12–21, 8 figs., 2 tabs., erlangen. flügel, e., riedel, p. & senowbari-daryan, b. (1988): plexoramea cerebriformis mello, ein hüufiges mikrofossil in triadischen flachwasserkalken: alge oder pilz?– mitt. ges. geol. bergbaustud. österr., 34/35, 263–277, 3 pls., wien. flügel, e. (1988): halimeda: paleontological record and paleoenvironmental significance.– coral reefs, 6, 123– 130, 12 figs., berlin. buggisch, w. & flügel, e. (1988): the precambrian/ cambrian boundary in the anti-atlas (morocco). discussion and new results.– in: jacobshagen, v. (ed.): the atlas system of morocco. studies on its geodynamic evolution. lecture notes in earth sciences, 15, 81–90, 1 pl., 2 figs., springer, berlin. flügel, e. & herbig, h.-g. (1988): mikrofazies karbonischer kalkgerölle aus dem paläozoikum des rif (marokko): ein beitrag zur paläogeographie der westmediterranen paläotethys im karbon.– facies, 19, 271– 300, pls. 43–46, 6 figs., erlangen. flügel, e., senowbari-daryan, b. & riedel, p. (1988): pantokratoria n.g. aus dem karn (obertrias) von hydra (griechenland) und der dolomiten (südalpen) – eine sclerospongie?– geologica palaeontologica, 22, 73–79, 2 pls., 1 fig., marburg. flügel, e. & kraus, s. (1988): the lower permian sexten breccia (sexten dolomites) and the tarvis breccia (carnic alps): microfacies, depositional environment and paleotectonic implications.– mem. soc. geol. ital., 34 (1986), 67–90, 5 pls., 4 figs., roma. stanton, r.j. & flügel, e. (1989): problems with reef models: the late triassic steinplatte “reef” (northern alps, salzburg/tyrol, austria).– facies, 20, 1–138, pls. 1–53, 32 figs., 2 tabs., erlangen. flügel, e. (1989): “algen/zement”-riffe.– arch. lagerstättenforsch. geol. bundesanst., 10, 125–131, wien. flügel, e. (1989): typen und wirtschaftliche bedeutung von riffkalken.– arch. lagerstättenforsch. geol. bundesanst., 10, 25–32, 4 figs., wien. flügel, e. & stanton, r.j. (1989): die steinplatte (oberrhätkalk) bei waidring/tirol: kein riff-modell.– geol. paläont. mitt. innsbruck, 16, 28–29, innsbruck. flügel, e., stanley, g.d. & senowbari-daryan, b. (1989): late triassic dasycladacean alga from northeastern oregon: significance of first reported occurrence in western north america.– j. paleont., 63/3, 374–381, 5 figs., tulsa. pomoni-papaioannou, f., flügel, e. & koch, r. (1989): depositional environments and diagenesis of upper jurassic subsurface spongeand tubiphytes reef limestones: altensteig 1 well, western molasse basin, southern germany.– facies, 21, 263–283, pls. 57–62, 5 figs., erlangen. flügel, e. & reinhardt, j. (1989): uppermost permian reefs in skyros (greece) and sichuan (china): implications for the late permian extinction event.– palaios, 4/6, 502– 518, 13 figs., tulsa. flügel, e. (1990): “einschnitte” in der entwicklung permischer kalkalgen.– mitt. naturwiss. ver. steiermark, 20, 99–124, 4 pls., 2 figs., graz. flügel, e. (1990): triassic and jurassic marine calcareous algae: a critical review. – in: riding, r. (ed.): calcareous algae and stromatolites, 481–503, 8 figs., springer, berlin. flügel, e., senowbari-daryan, b. & di stefano, p. (1990): lercaritubus problematicus n.gen. n.sp., a lower permian reef organism from western sicily.– boll. soc. paleont. ital., 29/3, 361–366, 1 pl., 3 figs., modena. flügel, e., di stefano, p. & senowbari-daryan, b. (1991): microfacies and depositional structure of allochthonous carbonate base-of-slope deposits: the late permian pietra di salomone megablock, sosio valley, western sicily.– facies, 25, 147–186, pls. 36–48, 9 figs., 5 tabs., erlangen. brandner, r., flügel, e. & senowbari-daryan, b. (1991): microfacies of carbonate slope boulders: indicator of the source area (middle triassic: mahlknecht cliff, western dolomites).– facies, 25, 279–296, pls. 69–74, 3 figs., 1 tab., erlangen. flügel, e. (1991): environmental analysis of allochthonous blocks and autochthonous mounds at the northern margin of the schlern-rosengarten (sciliar-catinaccio) platform.– in: brandner, r., flügel, e., koch, r. & yose l.a. (eds.): the northern margin of the schlern/sciliarrosengarten/catinaccio platform, 200 years dolomite, dolomieu conference on carbonate platforms and dolomitization, guidebook excursion a, 41–55, 16 figs., ortisei/st. ulrich. flügel, e. & höfling, r. (1991): northern alps/ austria. ecology and facies of upper triassic reefs. late cretaceous coral-rudist facies of the gosau area. – excursion b2 vi. international symposium on fossil cnidaria including archaeocyatha and porifera, 13 p., münster. brachert, t.c., buggisch, w., flügel, e., hüssner, h.m., joachimski, m.m., tourneur, f. & walliser, o.h. (1992): controls of mud mound formation: the early devonian kess-kess carbonates of the hamar laghdad, antiatlas, morocco.– geol. rundschau, 81, 15–44, 25 figs., 4 tabs., stuttgart. flügel, e. & flügel-kahler, e. (1992): phanerozoic reef evolution: basic questions and data base.– facies, 26, 167–278, 14 figs., erlangen. senowbari-daryan, b., weidlich, o. & flügel, e. (1992): erster nachweis von “favreinen” (crustaceenkoprolithen) aus dem perm (oberperm, oman-berge).– paläont. z., 66, 187–196, 3 figs., 1 tab., stuttgart. flügel, e. & krainer, k. (1992): allogenic and autogenic controls of reef mound formation: late carboniferous auloporid coral buildups from the carnic alps, italy.– n. jb. geol. paläont. abh., 185/1, 39–62, 9 figs., stuttgart. 216 geologia croatica 57/2 217in memoriam – prof. dr. erik flügel buggisch, w. & flügel, e. (1992): mittelbis oberdevonische karbonate auf blatt weilburg (rheinisches schiefergebirge) und in randgebieten: initialstadien der riffentwicklung auf vulkanschwellen.– geol. jb. hessen, 120, 77–97, 6 figs., 1 tab., 3 pls., wiesbaden. grötsch, j. & flügel, e. (1992): facies of sunken early cretaceous atoll reefs and their capping late albian drowning succession (northwestern pacific).– facies, 27, 153–174, pls. 31–36, 3 figs., 1 tab., erlangen. flügel, e., velledis, f., senowbari-daryan, b. & riedel, p. (1992): rifforganismen aus “wettersteinkalken” (karn) des bükk-gebirges, ungarn.– geol. paläont. mitt. innsbruck, 18, 35–62, 5 figs., 9 pls., innsbruck. flügel, e., groiss, j.t., koch, r., senowbaridaryan, b. & zeiss, a. (1992): excursion a 5. facies and diagenesis of sponge-algal mudmounds (franconian alb).– 13th ias regional meeting on sedimentology, excursion guide-book, 99–132, 35 figs., jena. senowbari-daryan, b., zühlke, r., bechstädt, t. & flügel, e. (1993): anisian (middle triassic) buildups of the northern dolomites (italy): the recovery of reef communities after the permian/triassic crisis.– facies, 28, 181–256, pls. 40–65, erlangen. weidlich, o., bernecker, m. & flügel, e. (1993): combined quantitative analysis and microfacies studies of ancient reefs: an integrated approach to upper permian and upper triassic reef carbonates (sultanate of oman).– facies, 28, 115–144, pls. 29–32, erlangen. flügel, e., alt, t., joachimski, m.m., riemann, v. & scheller, j. (1993): korallen-riffkalke im oberen malm (unter-tithon) der südlichen frankenalb (laisacker, marching): mikrofazies-merkmale und fazies-interpretation.– geol. bl. no-bayern, 43, 33–56, pls. 4–7, 2 figs., 1 tab., erlangen. flügel, e. & hagdorn, h. (1993): dasycladaceen aus dem oberen muschelkalk (mitteltrias) des hohenloher landes, süddeutschland.– zitteliana, 20, herm/hagnfestschrift, 93–103, 2 pls., 2 figs., münchen. flügel, e. (1993): detlef wurm, 1947–1992.– geol. bl. no-bayern, 43, 397–400, 1 fig., erlangen. senowbari-daryan, b. & flügel, e. (1993): tubiphytes maslov, an enigmatic fossil: classification, fossil record and significance through time. part i. discussion of late paleozoic material.– boll. soc. paleont. ital., spec. vol. 1, 353–382, 11 pls., 10 figs., modena. grötsch, j., schroeder, r., noé, s. & flügel, e. (1993): carbonate platforms as recorders of high-amplitude eustatic sea-level fluctuations: the late albian appenninica-event.– basin research, 5, 197–212, oxford. flügel, e. (1993): late palaeozoic algae from the alps: a short summary.– in: höfling., r., moussavian, e. & piller, w. (eds.): facial development of algaebearing carbonate sequences in the eastern alps. field trip guidebook alpine algae ‘93. 2 p., münchen. senowbari-daryan, b. & flügel, e. (1993): triassic reefs and platform carbonates in the northern calcareous alps.– in: höfling., r., moussavian, e. & piller, w. (eds.): facial development of algaebearing carbonate sequences in the eastern alps. field trip guidebook alpine algae ‘93. 14 p., 12 pls., 5 figs., münchen. senowbari-daryan, b. & flügel, e. (1993): algal associations of late triassic reef and platform facies.– in: höfling., r., moussavian, e. & piller, w. (eds.): facial development of algae-bearing carbonate sequences in the eastern alps. field trip guidebook alpine algae ‘93. 12 p., 7 figs., münchen. senowbari-daryan, b. & flügel, e. (1993): late triassic open platform algal associations and loferites (western styria).– in: höfling., r., moussavian, e. & piller, w. (eds.): facial development of algaebearing carbonate sequences in the eastern alps. field trip guidebook alpine algae ‘93. 4 p., 1 fig., münchen. flügel, e. (1994): pangean shelf carbonates: controls and paleoclimatic significance of permian and triassic reefs.– in: klein, g.d. (ed.): pangea: paleoclimate, tectonics, and sedimentation during accretion, zenith and breakup of a supercontinent.– geol. soc. america, spec. paper, 288, 247–266, 8 figs., 1 tab., boulder. flügel, e., ramovs, a. & bucur, i.i. (1994): middle triassic (anisian) limestones from bled, northwestern slovenia: microfacies and microfossils.– geologija, 36, 157–181, 7 pls., 2 figs., ljubljana. stanton, r.d., jr. & flügel, e. (1995): an accretionary distally steepened ramp at an intraplatform basin margin: an alternative explanation for the upper triassic steinplatte ‘reef’ (northern calcareous alps, austria).– sed. geol., 269–286, 9 figs., amsterdam. flügel, e. & koch, r. (1995): controls on the diagenesis of triassic carbonate ramp sediments: steinplatte, northern alps, austria.– geol. paläont. mitt. innsbruck, 20, 283–311, 4 pls., 11 figs., innsbruck. flügel, h.w. & flügel, e. (1996): umwachsung eines gastropoden durch das skelett einer rugosen koralle: hinweis auf die primäre skelettmineralogie der rugosa.– paläont. z., 70, 1/2, 53–65, stuttgart. senowbari-daryan, b. & flügel, e. (1996): a problematic fossil revealed: pycnoporidium? eomesozoicum flügel, 1972 (late triassic, tethys) not an enigmatic alga but a strophomenid brachiopod (gosaukammerella n.g.).– facies, 34, 83–100, pls. 21–27, 3 figs., 1 tab., erlangen. keller, m. & flügel, e. (1996): early ordovician reefs from argentina: stromatoporoid vs stromatolite origin.– facies, 34, 177–192, pls. 45–48, 5 figs., erlangen. flügel, e. & bernecker, m. (1996): upper triassic reefs of the south tethyan margin (oman).– göttinger arb. geol. paläont., sonderband 2, 273–277, 1 pl., 2 figs., göttingen. flügel, e., kiessling, w. & golonka, j. (1996): phanerozoic reef patterns: data survey, distribution maps and interpretation.– göttinger arb. geol. paläont., sonderband 2, 391–396, 2 figs., göttingen. flügel, e. & link, m. (1996): upper triassic reefs of southwestern turkey: evidence of reef boulders (‘cipits’).– göttinger arb. geol. paläont., sonderband 2, 279–283, 1 pl., 2 figs., göttingen. flügel, e. & senowbari-daryan, b. (1996): evolution of triassic reef biota: state of the art.– göttinger arb. 218 geologia croatica 57/2 219in memoriam – prof. dr. erik flügel geol. paläont., sonderband 2, 285–294, 4 pls., 2 figs., 1 tab., göttingen. flügel, e., senowbari-daryan, b. & rigby, j.k. (1996): upper permian inozoid sponges from djebel tebaga.– göttinger arb. geol. paläont., sonderband 2, 313–315, 1 pl., 1 fig., göttingen. senowbari-daryan, b. & flügel, e. (1996): nachweis einiger riff-foraminiferen und problematika in den norischen dachsteinkalken des gosaukammes (österreich).– jb. geol. bundesanst., 139/2, 247–271, 4 pls., 3 figs., wien. flügel, h.w. & flügel, e. (1996): ein briefwechsel zwischen alois flügel und lilly wildgans.– campus f (fürstenfeld), 34, 38–43, fürstenfeld. flügel, e. & flügel-kahler, e. (1997): der rote korallenkalk in der hethiter-mauer von bogazköy (anatolien): mikrofazies und herkunft.– geol. bl. no-bayern, 47, groiß-festschrift, 321–338, pls. 23–24, 1 fig., erlangen. flügel, ch., joachimski, m.m. & flügel, e. (1997): römische keramik mit marmormagerung: herkunftsbestimmung mit hilfe von stabilen isotopen (auerbergtöpfe aus süddeutschland).– archäol. korrespondenzbl., 27, 265–284, mainz. flügel, e. & mörtl, j. (1997): schriftenverzeichnis franz kahler (1900–1995).– carinthia ii, 107, 29–44, klagenfurt. flügel, ch., flügel, e., joachimski, m.m. & wagner, u. (1997): auerberg black fabric – an archaeological and archaeometric approach to roman rough ware.– rei cretariae romanae factorum acta, 35, proceedings conference 20 york and newcastle-upon-tyre 1996, 85–88, 4 figs., abingdon. flügel, e. & flügel, ch. (1997): applied microfacies analysis: provenance studies of roman mosaic stones.– facies, 36, 1–48, pls. 1–14, 5 figs., 8 tabs., erlangen. flügel, e., fohrer, b., forke, h., krainer, k. & samankassou, e. (1997): cyclic sediments and algal mounds in the upper paleozoic of the carnic alps.– excursion b 1. 18th ias regional european meeting, heidelberg. gaea heidelbergensis, 4, 79–100, 13 figs., heidelberg. koch, r., flügel, e., dimke, m., hasselmeyer, b., michel, u., rossner, r. & sobott, r. (1997): die ‘angewandte faziesforschung’ am institut für paläontologie in erlangen.– zbl. geol. paläont. teil i, 1996, h. 9/10, 989–1032, 10 figs., 3 tabs., 2 pls., stuttgart. flügel, ch., flügel, e., joachimski, m. & wagner, u. (1997): analisi archeometrica sulla ceramica tipo auerberg.– in: santoro bianchi, s. & fabbri, b. (eds.): il contributo delle analisi archeometriche allo studio delle cermamiche grezze e comuni. il rapporto forma/funzione/impasto, 92–94, 3 figs., university press, bologna. flügel, e. & maronde, d. (1997): riff-evolution. ein interdisziplinäres forschungsprojekt der dfg.– in: steininger, f. & maronde, d. (eds.): städte unter wasser: 2 milliarden jahre.– kleine senckenbergreihe, 24, 3–5, 2 figs., frankfurt. flügel, e. (1997): riffe heute und früher. die entwicklung eines ökosystems in der geologischen zeit.– in: steininger, f. & maronde, d. (eds.): städte unter wasser: 2 milliarden jahre.– kleine senckenbergreihe, 24, 13–18, 1 fig., frankfurt. flügel, e. & flügel-kahler, e. (1998): die kalkalge anthracoporella spectabilis pia aus dem oberkarbon der karnischen alpen: ein vergleich mit rezenten dasycladalen grünalgen.– mitt. ref. geol. paläont. landesmuseum joanneum, sonderheft 2, 175–198, 3 pls., 1 fig., graz. bernecker, m., weidlich, o. & flügel, e. (1999): response of triassic coral reef communities to sealevel fluctuations, storms and sedimentation: evidence from a spectacular outcrop (adnet, austria).– facies, 40, 229– 278, pls. 30–46, 13 figs., 1 tab., erlangen. kiessling, w., flügel, e. & golonka, j. (1999): paleoreef maps: evaluation of a comprehensive database of phanerozoic reefs.– amer. ass. petrol. geol. bull., 84, 1552–1587, 16 figs., tulsa. flügel, e. (1999): microfacies-based provenence analysis of roman imperial mosaic and sculpture materials from bavaria (southern germany).– facies, 41, 197–208, pls. 43–46, 1 fig., erlangen. flügel, e. (2000): mikrofazies: grundlagenforschung und anwendung.– mitt. ges. geol. bergbaustud. österr., 43, 43–44, wien. weidlich, o., bernecker, m. & flügel, e. (2000): hartgründe und lösungshohlräume im obertriadischen riff von adnet (österreich): hinweise auf die amplitude relativer meeresspiegelschwankungen.– mitt. ges. geol. bergbaustud. österr., 43, 146–147, 1 fig., wien. kiessling, w. & flügel, e. (2000): late paleozoic and late triassic limestones from north palawan block (philippines): microfacies and paleogeographical implications.– facies, 43, 39–78, pls. 6–16, 8 figs., 3 tabs., erlangen. kiessling, w., flügel, e. & golonka, j. (2000): fluctuations in the carbonate production of phanerozoic reefs.– in: insalaco, e., skelton, p.w. & palmer, t.j. (eds.): carbonate platform systems: components and interactions. geol. soc. london, spec. publ., 178, 191– 215, 9 figs., london. flügel, e. & senowbari-daryan, b. (2001): tethyan triassic reefs.– in: stanley, g.d. (ed.): ancient reef ecosystems. 217–249, 3 figs., kluwer academic/plenum publishers, new york. senowbari-daryan, b., flügel, e. & preto, n. (2001): tethysocarnia cautica n.gen. n.sp., a sessile foraminifer from late ladinian and carnian reefs of the western and southern tethys.– geologica palaeontologica, 35, 105–119, 4 pls., 3 figs., 1 tab., marburg. flügel, e. & kiessling, w. (2002): a new look at ancient reefs.– in: kiessling, w., flügel, e. & golonka, j. (eds.): phanerozoic reef patterns. sepm spec. publ., 72, 3–20, tulsa. kiessling, w. & flügel, e. (2002): paleoreef – a database on phanerozoic reefs.– in: kiessling, w., flügel, e. & golonka, j. (eds.): phanerozoic reef patterns. sepm spec. publ., 72, 77–94, tulsa. 218 geologia croatica 57/2 219in memoriam – prof. dr. erik flügel flügel, e.(2002): triassic reef patterns.– in: kiessling, w., flügel, e. & golonka, j. (eds.): phanerozoic reef patterns. sepm spec. publ., 72, 391–464, tulsa . flügel, e. & kiessling, w. (2002): patterns of phanerozoic reef crises.– in: kiessling, w., flügel, e. & golonka, j. (eds.): phanerozoic reef patterns. sepm spec. publ., 72, 691–734, tulsa. kiessling, w., flügel, e. & golonka, j. (2002): from patterns to processes: the future of reef research.– in: kiessling, w., flügel, e. & golonka, j. (eds.): phanerozoic reef patterns. sepm spec. publ., 72, 735–744, tulsa. flügel, e. (2003): analysen spätantiker und mittelalterlicher keramik aus tiffen.– in: dolenz, h., flügel, ch. & öllerer, c. (eds.): die rettungsgrabung auf dem ‘púrpal’ in tiffen im jahre 2002.– rudolfinum, jb. landesmus. kärnten, 2002 , 145–147, klagenfurt. weidlich, o., kiessling, w. & flügel, e. (2003): the permian-triassic boundary interval as a model for forcing marine ecosystem collapse by long-term atmospheric oxygen drop.– geology, 31/11, 961–964, boulder. krainer, k., flügel, e., vachard, d. & joachimski, m. (2003): a close look at late carboniferous algal mounds: schulterkofel, carnic alps, austria.– facies, 49, 325–350, pls. 54–60, 6 figs., 2 tabs., erlangen. flügel, e. & singh, i. (2003): stromatoporoid-grade and other sponge fossils from the upper krol formation of the lesser himalaya: implications for the biotic evolution around the precambrian-cambrian boundary interval.– facies, 49, 351–372, pls. 61–66, 2 figs., 1 tab., erlangen. kiessling, w., flügel, e. & golonka, j. (2003): patterns of carbonate platform sedimentation.– lethaia, 36, 195–225, oslo. flügel, ch., flügel, e., häusler, w., joachimski, m., koller, j., baumer, u. & wagner, u. (2004): roman coarse ware from bavaria, austria and northern italy.– hyperfine interactions, 154, 231–251, electronically published: www.kluweronline.com/issn/0304–3843. flügel, e., thiedig, f., dolenz, h. & kuss, j. (2004): herkunftsbestimmung des frühzeitlichen mosaikmaterials im bereich des repräsentantenhauses und in den unteren a/a bauten am magdalensberg, kärnten.– rudolfinum, jb. landesmus. kärnten 2003, klagenfurt. flügel, e. (2004): microfacies of carbonate rocks. analysis, interpretation, application.– 997 p., 151 pls., springer, berlin–heidelberg–new york. 220 geologia croatica 57/2 editorial.indd 1 �edi to rial wi th the be gin ni ng of this year, the jour nal you ha ve in your ha nd or read on in ter net, geo lo gia croa ti ca has (par tly) changed edi to rs-in-chief. the for mer edi to rs prof. igor vlahović and dr. ivo velić resig ned wi th ja nua ry 2008, be cau se the infl ow of ma nus crip ts dec li ned in re ce nt yea rs due to the fa ct that ar tic les pub lis hed in our jour nal we re not con si de red for scien ti fi c pro mo tion in croa tia. they wan ted, and ha ve succeded, in re mo ti va ti ng the croa tian geo lo gi cal and lar ger scienti fi c com mu ni ty, and sin ce ja nua ry 2008, ar tic les pub lis hed in geo lo gia croa ti ca wi ll be eli gib le for scien ti fi c pro mo tion. in this way they ha ve he lped to main tain the jour nal. dr. ivo velić ag reed to be reap poin ted as edi tor in the tran si tio nal period to stre ss the con ti nui ty of edi to rial po li cy and to he lp the new inco mi ng edi tor, prof. mla den juračić, and the new edito rial boa rd. the edi to rs and the edi to rial boa rd are indeb ted to prof. igor vlahović for all his ef fo rt and ti me he spe nt to im pro ve geo lo gia croa ti ca to be as good and ti me ly as it is now. he is, wit hout any dou bt, the per son mo st res pon sib le for the large im pro ve me nt in the scien ti fi c con te nt as we ll as the graphical edi ti ng, layout and web si te of the jour nal. this can be seen in the ac knowled ge men ts that the jour nal and the edito rs ha ve been re cei vi ng over the la st 15 yea rs. a re ce nt e-mail from the wor ld re nowned and es tee med pro fes sor jo hn g. ram say il lus tra tes this ve ry we ll: i was sad to hear that you are bo th re sig ni ng as edi to rs of geo lo gia croa ti ca. when i re cei ved the jour nal on fi r st becom mi ng a mem ber of the in ter na tio nal scien ti fi c ad vi so ry boa rd i was extrem ly im pres sed wi th the qua li ty of the journal and its excel le nt mo de rn for mat. howe ver i do see your prob le ms cau sed by the scien ce ci ta tion ba ses not bei ng wil ling to in clu de geo lo gia croa ti ca in their co ve ra ge. howe ver, i do ho pe that the jour nal con ti nues be cau se it has al rea dy pub lis hed va luab le scien ti fi c ma te rial. pro fes sor pe ter w. skel ton from open uni ver si ty, mil ton keynes, uk se nt si mi lar let ter: i shou ld li ke to re co rd my deep ap pre cia tion of the outstan di ng de di ca tion of the pre vious chief edi to rs, dr. ivo velić and dr. igor vlahović, to get her wi th the sup po rt of the con tinui ng ma na gi ng edi tor, ms. ali sa mar tek, to the main te nan ce of con sis ten tly hi gh edi to rial and pro duc tion stan dar ds of the jour nal and their great ef for ts to en han ce in ter na tio nal acce ss to its con ten ts throu gh va rious geos cien ce da ta ba ses and the jour nal’s excel le nt web si te. i am con fi de nt that, if gi ven suf fi cie nt (a nd we ll-deserved) sup po rt from the na tio nal geoscien ce in sti tu tio ns and, in deed, in ter na tio nal mem be rs of the geos cien ce re sear ch com mu ni ty wi th in te res ts in the re gion, the new edi to rial boa rd shou ld be ab le to bui ld on the so lid foun da tio ns laid by their pre de ce ssors and con ti nue to nur ture the im por ta nt pla ce of the jour nal in the geo lo gi cal li te ratu re and the hi gh re ga rd in whi ch it is he ld. when re ferri ng to this pe riod we wou ld li ke to stre ss the im por tan ce of our lan gua ge re viewer, dr. ju lie rob son who se ef for ts ha ve con tri bu ted to the hi gh lan gua ge qua li ty of the artic les and jour nal, es pe cial ly sin ce mo st aut ho rs are not engli sh na ti ve spea ke rs. our jour nal geo lo gia croa ti ca has been con ti nuous ly publis hed sin ce 1947 and is bei ng in dexed in al mo st all re le va nt da ta ba ses for the geos cien ces (geo ref, geo ba se, geo lo gi cal ab strac ts, geoar chi ve, geo tit les, sco pus, etc.). wi th this number, geo lo gia croa ti ca en te rs its se ven th de ca de and we wi ll ma ke eve ry ef fo rt to try to bri ng the jour nal qua li ty and ti meli ne ss to the le vel nee ded to en ter the web of scien ce (thomson scien ti fi c). the sco pe of the jour nal wi ll re main broad, and we wou ld li ke to be co me a lea di ng re gio nal geos cien ce jour nal. howe ver, we wou ld li ke to re cei ve mo re ma nus crip ts concer ning the di na ri des, the ad ria tic/mediterranean re gion, pan no nian ba sin, and/or kar st is sues. we plan to in tro du ce an on li ne sub mis sion system ve ry soon and to stren gthen the ru les for the tec hni cal qua li ty of the ma nus crip ts re cei ved, in or der to im pro ve and shor ten the handli ng pe riod. also, we de ci ded to publish 3 issues per year and to shift our publication dates fowards the beginning of the year (february, june, october). ef fi cie nt and expe di tious han dli ng of ma nus crip ts is con strai ned by: (i) the edi to rial system (whi ch we wi ll try to im pro ve), (ii) the re view pro ce ss (iden ti fi ca tion of in di vi dua ls pre pa red to pro vi de de tai led re views in a rea sowhy (a nd how) to pub li sh in geo lo gia croa ti ca geologia croatica 61/1 1–2 0 figs. 0 tabs. zagreb 2008 geologia croaticageologia croatica � editorial.indd 1editorial.indd 1 24.6.2008 11:04:1524.6.2008 11:04:15 geologia croatica geologia croatica 61/1 2 nab le ti me, is always dif fi cu lt), and (iii) by aut ho rs’ di li gen ce in ob ser vi ng the pub li ca tion ru les of the jour nal. many aut ho rs ca re ful ly read the in struc tio ns to aut ho rs and sub mit ma nus crip ts that are in ac cor dan ce wi th the gui deli nes. they use a spel lchec ker. su ch ma nus crip ts are ea si ly han dled, as the edi to rs can fo cus on the scien ti fi c con te nt alo ne. howe ver, so me of the ma nus crip ts may be scien ti fi cally sou nd, but suf fer from prob le ms whi ch the aut ho rs shou ld ad dre ss. con si de ra tion of the poin ts be low wi ll con si de rab ly he lp aut ho rs wi th the pre sen ta tion of their wo rk. the se have been adap ted from anot her edi to rial (bennett, 2007). in clu de a tes tab le hypot he sis – scien ce is dri ven by hypothe ses. wit hout one, a pa per lac ks fo cus and ri gor. open en ded scien ce is weak, of ten re pe ti ti ve, and unin te res ti ng. ge ne ra ting a hypot he sis (or we ll de fi ned ob jec ti ve) in ad van ce of doing the wo rk tig hte ns up the stu dy and ma kes the re sul ts mo re mea nin gful. ca re ful ly do cu me nt what you ha ve do ne – so that your lo ca tio ns can be re vi si ted, your ob ser va tio ns con fi r med, and/ or your expe ri me nt can be dup li ca ted by ot he rs. pro vi de adequa te sta tis ti cal ana lysis of your da ta – if a stu dy in clu des the col lec tion of da ta, it is es sen tial they be analysed sta tis ti cal ly. wit hout sta tis ti cs the rea der wi ll ha ve no idea if the re sul ts mean anythi ng. ci te a rea so nab le num ber of re fe ren ces – we all know the re are lot of pa pe rs on any sub je ct, so the re is no rea son to ci te them all. on ly exam ple pa pe rs need to be ci ted as we ll as spe ci fi c pa pe rs that are cri ti cal ly ad dres sed in the new stu dy. ideal ly so mewhe re be tween 30 and 40 re fe ren ces are nee ded for the ave ra ge pa per, no mo re. and ob vious ly le ss than a dozen re fe ren ces is too few. keep it short – how ma ny of us ha ve ac tual ly read a 30+ pa ge pa per? pro bab ly on ly the aut hor and one or two col leagues wor ki ng in the sa me fi e ld. lo ng pa pe rs suf fer from verbo si ty and are te dious to read. the ideal pa per len gth is somewhe re arou nd a do zen prin ted pa ges, whi ch is le ss than 2000 wor ds on ave ra ge. fol low the jour nal style – che ck the gui de for aut ho rs and be su re to fol low the jour na l’s style for the va rious sectio ns of your pa per. ma ke su re your sub mis sion is al so comple te. so me lea ve out the keywor ds, abstra ct and tit le pa ge. fol low the et hi cal gui de li nes – re ce nt fai lu res to fol low the et hi cal gui de li nes for aut ho rs ha ve in clu ded mul tip le submis sion of a pa per to mo re than one jour nal, and pla gia ri sm of pre vious ly pub lis hed wo rk by anot her aut hor. the se are groun ds for im me dia te re jec tion. ma ke the en gli sh rea dab le – if en gli sh is not your na ti ve lan gua ge it is im por ta nt to ha ve a na ti ve en gli sh spea ker/writer edit your sub mis sion so the en gli sh is rea dab le. if your sub mis sion fol lows the se poin ts the re is a good chan ce that the ma nus cri pt wi ll be ac cep ted. of cour se the fi nal de ter mi na tion on a pa per de pen ds on the scien ti fi c con te nt. anot her impor ta nt be ne fi t is the ove ra ll im pro ve me nt of the qua li ty of our jour nal, so that rea der frus tra tion is re du ced. we all know what a plea su re it is to read a good pa per. wi th a little extra wo rk, aut ho rs cou ld wri te mu ch bet ter pa pe rs that wou ld ma ke sig ni fi ca nt con tri bu tio ns to knowled ge and be of great he lp to reade rs and ot her scien tis ts. so when you de ci de to sub mit your next ma nus cri pt to geo lo gia croa ti ca plea se se nd mail to our ma na gi ng edi tor ms ali sa mar tek (edi to rial.offi ce@geologia-croatica.hr) or/ and to us (edi to r@geologia-croatica.hr). re fe ren ces bennett, j.p. (2007) sim ple gui de li nes to fol low in pre pa ri ng a manus cri pt for sub mis sion to scien ce of the to tal en vi ronment (edi torial). – scien ce of the to tal en vi ron., 387, 1–2 mladen juračić and ivo velić editorial.indd 2editorial.indd 2 26.6.2008 9:16:0326.6.2008 9:16:03 geol. croat. 50/2 118 zagreb 1997 i znanstveni skup u povodu 80. obljetnice zivota akademika milana heraka (scientific meeting dedicated to the 80th anniversary of professor m. herak) vladimir jelaska znanstveni skup u povodu 80. ob ljctnicc zivota akadcmika milana i-icraka, adrian jc 5. ozujka u zagre­ bu. stara gradska vijecnica pruzila je izvanredan ugodaj kojcm jc nazocilo oka 250 sudionika. skup su prircdili geoloski oclsjek prirodos!ovno-matematickog fakulte ta sveucilista ii zagrcbu i institul za geoioska ist razivanja zagreb, a organi zacij ski odbor sacinjavali su profe­ soravi diplomandi dan as aktivni svcucilisni nastavnici i znanstvenici. pozelrave profcsoru heraku uputili su: akademik iva padovan potprcdsjcdnik hrvatskc akadcmije znanosti i umjctnosti, prof. elf sc. biserka nagy dekanica priro­ dos!ovno-matematickog [akulteta, prof. dr sc. darko mayer dekan rudarsko-gcolos ko-naftnog fakuiteta, dr sc. boziclar bionclic ravnatelj insliluta za geoioska department of geology and palaeontology, faculty of science, university of zagreb, ul. kralja zvo ni mi ra 8, 1'ir-loooo zagreb, croatia. istrazivanja, mr sc. ziata polsak-jurisic hrvalski priro­ closlovni muzej, prof. dr sc. stanko buser u imc slovcn­ skih geologa, prof. clr sc. radovan domac profesorov prijatclj i kolega jos iz gimnazijskih clana, ie prcdsjecl ­ nik drustva zumbercana "taclija smiciklas" gospoclin petar badovinac. prijcpodncvni program skupa obuhvatio jc refcratc o znanst venom djclu i nastavnom radu prof. clr sc. milana hcraka, a u poslijepodnevnom radu oddano jc 16 znanstvenih priopcenja u kojima su sudje loval i i sloven ski geolozi. skup jc zavrs io domjenkom kojeg su u cast akade­ mika milana beraka priredili njcgovi prijatclji zum ­ bercani (drustvo tadija smiciklas). 1. introduction permo-triassic (p/tr) boundary events, which took place approximately 250 ma ago, led to the most extensive mass extinction in the history of life. a number of possible explanations for this profound break in the evolution of life have been proposed, such as volcanic activity, sea-level fluctuation, changes in sea-water chemistry, an extra-terrestrial impact event and various related factors (yoichi, 1994). the most recently proposed cause of the mass extinction at the end of the permian is a combination of these more or less co-occurring events operating in three phases (ervin, 1996). the first began with the marine regression during the late permian and resulted in the destruction of many marine basins, reduction in the habitat area of many organisms and increased climatic instability. the second phase involved the eruption of the siberian traps and further environmental degradation. the final phase may have started immediately prior to the boundary when the late permian regression ended and the earliest triassic transgression begun. the global events outlined above coincide with isotope and elemental anomalies recorded in several p/ tr boundary sections all stable isotope event markers near the permo-triassic boundary in the karavanke mountains (slovenia) tadej dolenec 1, 2, sonja lojen 2, stanko buser 1 and matej dolenec 3 over the world. one of the most remarkable anomalies is the worldwide negative shift of δ13c of inorganic and organic carbon across the p/tr boundary (magaritz et al., 1992; wang et al., 1994; wolbach et al., 1994; faure et al., 1995). a corresponding oxygen isotopic shift is more or less parallel, but less pronounced. furthermore, significant shifts in sulphur (kajiwara et al., 1994) and strontium isotopes (kramm & wedepohl, 1991) have also been recorded. in this study we present the results of stable isotope analysis of the p/tr boundary section in the karavanke mountains (fig. 1), and discuss their implications with respect to a better understanding of the nature and causes of the p/tr boundary events in this part of western palaeotethys. 2. geological setting and stratigraphy in the southern karavanke mountains, the middle permian val gardena formation of mostly fluvial origin, is overlain by a 270 m thick upper permian carbonate sequence, which was named the karavanke formation (buser, 1974). the boundary between the two formations is transitional and is characterized by thin sandy red dolomite layers alternating with the topmost val gardena shales and sandstones. the thickness of the transitional unit which grades upward into the karavanke formation is about 5 m (dolenec et al., 1981). the evaporitic sequence, up to 70 m thick, represents the basal unit of the karavanke formation composed of cellular dolomite, which alternates with rare black bituminous shales, and grey vuggy dolomites. the evaporitic sequence is overlain by a 200 m thick succession of fossiliferous biomicritic dolomites. the upper permian age of these beds is indicated by calcareous algal assemblages, as well as by foraminifera (ramov©, 1986). the lithostratigraphic boundary between the upper permian karavanke formation and the lower triassic (scythian) beds is placed at the end of the sedimentation of the well-bedded grey dolomicrite. it is followed by a red coloured partly terrigenous sequence predominantly composed of thin-bedded siltstones, mudstones and sandstones alternating with micritic dolomites, that contain no characteristic fossils. these earliest triassic beds were deposited in an extremely shallow sea, which geol. croat. 52/1 77 81 2 figs. zagreb 1999 key words: permo-triassic boundary, karavanke mountains, slovenia, oxygen, carbonate carbon, organic carbon stable isotopes. 1 department of geology, university of ljubljana, aπkerëeva 12, slo-1000 ljubljana, slovenia. 2 department of environmental sciences, joæef stefan institute, jamova 39, slo-1000 ljubljana, slovenia. 3 geoexp d.o.o., slap 21, slo-4290 træië, slovenia. abstract stable isotope analyses of carbonates and organic matter from the permo-triassic boundary section in the karavanke mountains, slovenia, indicate a further example of the “light carbon” event across the boundary. in this section the changes in carbon isotope values were a direct result of the culmination of the marine regression and associated events at the end of the permian, which caused a drop in primary productivity, as well as related local environmental changes, with no evidence of any considerable diagenetic overprint. 78 geologia croatica 52/1 gradually became a wide, extensive mud flat (assereto et al., 1973). their thickness is about 25 m. in the investigated area these beds are mostly overlain by lower triassic dark grey and brown micritic and sparitic limestones intercalated with oolitic limestone, marls and shales. 3. materials and methods the boundary profile in the karavanke mountains was sampled at 10 m intervals, except in the vicinity of the lithostratigraphically defined p/tr boundary where sampling intervals were reduced to 20 cm. the relative stratigraphic position of the samples and the analytical results are presented in fig. 2. the isotopic measurements were carried out on un-dolomitized limestone and un-calcitized dolomite samples. the mineralogy of the carbonate phases was determined by x-ray diffractometry and by examination of thin sections by standard optical methods, including staining with alizarinred. all samples were also evaluated by petrographic methods to assess their diagenetic history. only unrecrystallized or insignificantly recrystallized samples were used for isotopic measurements. samples were obtained as a split of powder prepared from rock chips remaining after thin section preparation. in order to speed up the reaction time and to ensure complete reaction of carbonates, powdered rock samples for δ18o and δ1 3c analysis were prepared by overnight digestion in >100% phosphoric acid at 50°c. co2 gas released during acid treatment was cryogenically cleaned and analyzed for o and c isotopic composition on a varian mat 250 mass spectrometer. data were corrected for kinetic fractionation between phosphoric acid and carbonates using fractionation factors of 1.00925 for calcite and 1.01038 for dolomite (beukes et al., 1990). the δ18o and δ13c values were normalized by assuming δ1 8o and δ1 3c values of -2 . 44‰ and +2 . 48‰ for iaea-co-1 standard on the pdb scale. for preparation of the total organic carbon, powdered whole rock samples were treated with heated 3m hydrochloric acid at 50°c to react with the carbonates. upon cessation of co2 evolution, excess acid was removed by repeated washing (three to four times) with doubly distilled water until a neutral ph was determined. after the final decanting of water, the carbonate free residues were oven-dried at 50°c. organic carbon isotope ratios were measured in the carbonate-free residues in the europa 20-20 stable isotope analyser (europa scientific ltd.) with the anca-nt preparation module for on-line combustion of bulk solid samples and chromatographic separation of the gases. organic carbon isotope values were calibrated using the iaea-ch-7 standard with a δ1 3c value of -3 1 .8‰ on the pdb scale. all bulk rock and carbonate-free residue samples were measured two or three times. the results are reported in the conventional delta notation as ‰ deviations from the pdb standard (craig, 1957) for oxygen, carbonate and organic carbon. the analytical precision based on multiple analysis of internal laboratory standards was ±0 . 02‰ for δ1 8o, ±0 . 01‰ for δ1 3cc a r b . a n d ±0 . 0 08‰ for δ1 3co r g ., respectively. overall analytical reproducibility of the isotopic data was ±0.15‰ for oxygen, ±0.1‰ for carbonate carbon and ±0.095‰ for organic carbon. 4. results and discussion the transition from middle permian to upper permian is characterized by a considerable enrichment of dolomite with 1 3c (from -2.50 to +3 . 83‰) and 1 8o (from -8.67 to -3 . 34‰) (dolenec et al., 1981), as well as by a drop in δ1 3c of total organic carbon (from -21.90 to -2 4 . 49‰). positive δ1 3c and δ1 8o shifts in dolomite (fig. 2) may reflect the transgression of the palaeotethys sea on the vast alluvial middle permian landscape. documentation of this transgression exists not only in the south of tethys, but also to the north in the zechstein basin (assereto et al., 1973). the general hypothesis, suggested to explain positive δ1 3c shifts of carbonate carbon, is that the expansion of shallow shelf areas increased the organic carbon burial rate and enriched the ocean in 13c (compton et al., 1990; faure et al., 1995). the corresponding oxygen isotope excursion is similar to that in δ1 3c, and also suggests a change from terrestrial to marine-evaporitic conditions. the δ1 3c of terrestrial plant remains in the val gardena formation varies between -22.13 and -21.65‰ (dolenec, 1984). these values are up to 2.8‰ more positive than those of the evaporitic sequence. a negative shift at the middle permian-upper permian transition most likely suggests that the ratio of terrestrial to marine organic carbon changed. fig. 1 reconstruction of the supercontinent pangea in the late permian after sun et al. (1989). the point indicates the approximate position of the studied area in the karavanke mountains. the dolomites of the basal evaporitic sequence show a variation of δ1 3cc a r b . in the range of +0.69 to +3 . 83‰, and of δ1 8o between -5.88 to -3 . 34‰. the oxygen isotopic composition of the evaporitic sequence is not as high as expected from recent evaporitic environments (tucker, 1990). the observed reduction in δ18o indicate an influx of fresh water into the evaporitic basin, less evaporation and/or a variety of different post-depositional processes, that may affect either oxygen or carbon or both stable isotopic records (brand & veizer, 1981; magaritz & holser, 1991). by selecting the least visibly weathered and recrystallized samples from the investigated sections we attempted to minimise the possible post-depositional effects. a weak positive correlation (r = 0.40) between δ1 8o and δ1 3c of the dolomite samples and a weak negative correlation (r = -0.22) between δ1 8o and δ1 3c of the limestone samples most probably suggests that the isotopically light meteoric water and dolomitizing fluids during diagenesis and burial to some extent reset the original whole rock oxygen and carbon isotopic composition. the low positive correlation (r = 0.51) between δ1 3cc a r b . and δ1 3co r g . indicates that the whole rock isotopic composition was not modified by the oxidation of organic matter during diagenesis. based on these observations, we tend to believe that the isotopic composition of the investigated karavanke mountain carbonate rocks has not been seriously altered after their formation and that the primary palaeoceanographic signal was not completely overprinted. the transition from permian to triassic is characterized by a prominent negative shift of carbonate δ1 3c as well as total organic carbon and a similar, but less pronounced δ1 8o decrease. the major drop of δ1 3cc a r b . a n d δ1 3co r g ., similar to that seen globally, begins approximately 15 m below the boundary. the δ1 3cc a r b . c u r v e reaches a minimum peak value of -1 . 86‰ about 8 m below the boundary and after that there is another minimum of -1 . 57‰ at the end of the permian and a positive excursion of +0 . 55‰ in the lowermost scythian, before settling to values which are 1 to 2‰ lower relative to those in the upper permian. the position of the negative δ1 3cc a r b . peak anomaly may indicate that the p/tr boundary in the karavanke mountains should be placed a little further downsection, since in the carnic alps a dramatic δ1 3ccarb. drop occurs right after the stratigraphic p/tr boundary which is placed within the lowermost 0.5 m of the 4 m thick oolitic tessero horizon or at its base (holser et al., 1991). in the karavanke mountains this oolitic unit at the base of the scythian was not recognized. the corresponding total organic carbon isotope curve is essentially parallel. the first (-2 9 . 89‰) and the second (-2 6 . 65‰) negative anomaly for δ1 3co r g . are coeval with the first two nega79dolenec, lojen, buser & dolenec: stable isotope event markers near the permo-triassic boundary... fig. 2 stable isotope composition of carbonates (δ13ccarb., δ18o), total organic carbon (δ13corg.) and carbon isotope fractionation between carbonate and total organic carbon (δ13ccarb.-org.) across the permo-triassic boundary in the karavanke mountains. a) dark grey and brown micritic and sparitic limestone intercalated with oolitic limestone, marls and shales; b) a red partly terrigenous sequence composed of siltstones, mudstones and sandstones alternating with micritic dolomites; c) light grey fossiliferous biomicritic dolomite; d) an evaporitic sequence composed of cellular dolomite intercalated with black bituminous shales and grey vuggy dolomites; e) a transitional unit composed of sandy red dolomite alternating with shales and sandstones; 1-3) carbonate and organic carbon anomalies. 80 geologia croatica 52/1 tive shifts observed for δ13c of carbonate carbon, while the third decrease of δ1 3corg. (-2 6 . 92‰) occurs in the triassic, 7 m below the third negative shift of δ1 3cc a r b . values. during the permian-triassic transition the karavanke mountains constituted a semi-restricted marine basin, surrounded by vast areas of an extremely shallow epicontinental sea into which a considerable amount of terrigenous material was transported (dolenec et al., 1981). the environmental stress conditions caused decreased bioproductivity in the upper water column and an associated decrease in dissolved carbonate (zheng et al., 1993). a drop of δ1 3c values in carbonate precipitates reflects this decrease. the incorporation of light carbon from eroded and oxidized organic matter into carbonates and photosynthetic marine organisms would also cause both to become isotopically lighter (wolbach et al., 1994). the variation between δ13ccarb. and δ1 3corg. values, which can be used to evaluate major changes in the carbon cycle by removing the effect of changes in the δ13c of the surface water dissolved inorganic carbon reservoir (hollander et al., 1993), also indicates changes in bioproduction. for the p/t r transition in the karavanke mountains the decreasing isotopic composition of total organic carbon of 6.5‰ (from -23.19 to -2 9 . 69‰) and increasing ∆δ1 3cc a r b . o r g . of 3.78‰ (from 24.66 to 28.44‰) about 8 m below the boundary can be explained by a dramatic decrease in primary production. this breakdown in the photosynthesis/ respiration cycle appears to coincide with events related to the accelerated fall in sea level and/or widespread volcanic activity in siberia. these events began substantially before the end of the permian and affected the carbon cycle long enough to cause a clear perturbation in both δ13c records. the δ13c shift of 3.5‰ (from -8.89 to -25.39‰) in total organic carbon toward higher values and the reduction in ∆δ1 3cc a r b . o r g . by 4.1‰ (from 28.23 to 24.13‰) at the p/tr boundary could be the consequence of a subsequent recovery period in the biological system before the sea gradually became a wide, extensive mud flat. this situation was changed after the sedimentation of the red terrigenous sequence, due to the earliest triassic marine transgression which spread anoxic bottom water over the entire region of the karavanke mountains, and marked the end of the period of extreme variability in δ1 3c of both carbonate and organic carbon. during this phase deposition of the lower scythian dark grey and brown limestones began. the variability of δ1 8o in the interval straddling the p/tr boundary shows slightly different trends with respect to those of δ1 3c in carbonate and organic carbon, roughly indicating environmental changes from marine to desultory evaporitic conditions affected by an excessive input of terrigenous material, and by local freshening of waters, due to the influx of more or less isotopically modified meteoric waters into the sedimentary environment. a significant drop of δ1 8o from 4 . 19‰ to -9 . 51‰ approximately 25 m above the boundary is stratigraphically coincident with abrupt changes in the lithology, as well as carbonate mineralogy of the rocks. the scythian limestones are considerably depleted in 1 8o (from 3 to 8‰) relative to both the underlying lowermost scythian dolomite and the upper permian dolomite of the karavanke formation. such depletion cannot be interpreted only in terms of dolomite-calcite fractionation which is thought to be between +3 and +4‰ (dickson, 1990). it may also be caused by a change in the δ1 8o of seawater, a decrease of salinity, changes in the depositional environment, diagenetic processes and burial, or some combination of all of these factors. due to the muddled oxygen isotopic pattern, it is difficult to give a definite explanation of the observed δ1 8o variations at the p/t r transition. however, it is important to note that the δ13c signals of inorganic and organic carbon are independent of lithology and are preserved in both scythian dolomite and limestone. 5. conclusions the results we have presented in this study indicate that the transition from the permian to the triassic in the karavanke mountains is characterized by a strongly negative complex pattern of carbonate and organic carbon anomalies, accompanied by changes in the δ1 8o values of the boundary carbonate rocks. these anomalies are supposed to record extremely adverse changes of the environment due to global events which marked the terminal permian productivity crash and the p/ t r boundary. we suggest a causal connection between the global carbon isotopic anomalies and the marine regression at the end of the permian, but the exact controls remain complex and enigmatic. acknowledgements the ministry of science and technology, republic of slovenia, and geoexp d.o.o., træië, slovenia financially supported this study. to both these institutions we express our sincere thanks. 6. references assereto, r., bosselini, a., fantini sestini, n. & sweet, w.c. (1973): the permian-triassic boundary in the southern alps (italy).in: logan, a. & hills, l.v. (eds.): the permian and triassic systems and their mutual boundary. albertal. soc. petrol. geol. mem., 2, 176-199. beukes, n.j., klein, c., kaufman, a.j. & hayes, j.m. (1990): carbonate petrography, kerogen distribution, and carbon and oxygen isotope variations in an early proterozoic transition from limestone to iron-formation deposition, traansvaal supergroup, south africa.econ. geology, 85, 663-690. 81dolenec, lojen, buser & dolenec: stable isotope event markers near the permo-triassic boundary... brand, u. & veizer, j. (1981): chemical diagenesis of a multicomponent carbonate system 2: stable isotopes.j. sediment. petrol., 51, 987-997. buser, s. (1974): neue feststellungen im perm der westlichen karavanken.carinthia ii, 164/84, 2737. compton, j.s., snyder, s.w. & hodell, d.a. (1990): phosphogenesis and weathering of shelf sediments from the southern united states: implications for miocene δ1 3c excursions and global cooling.geology, 18, 1227-1230. craig, h. (1957): isotopic standards for carbon and oxygen and correction factors for mass spectrometric analysis of carbon dioxide.geochim. cosmochim. acta, 12, 133-149. dickson, t. (1990): carbonate mineralogy and chemistry.in: tucker, m.e. & wright, v.p.: carbonate sedimentology. blackwell scientific publications, oxford, 482 p. dolenec, t. (1984): the origin of the uranium mine æirovski vrh.unpublished phd thesis, university of ljubljana, 187 p. dolenec, t., ogorelec, b. & pezdi», j. (1981): upper permian and scythian beds in the træië area.geologija, 24/2, 217-238, ljubljana. ervin, d.h. (1996): permian global bio-events.in: waliser, o.h. (ed.): global events and event stratigraphy in the phanerozoic. springer-verlag, berlin, 251-264. faure, k., de wit, m.j. & willis, j.p. (1995): late permian global coal hiatus linked to 1 3c depleted co2 flux into the atmosphere during the final consolidation of pangea.geology, 23, 507510. hollander, d.j., mckenzie, j.a. & kenneth, j.h. (1993): carbon isotope evidence for unusual plankton blooms and fluctuation of surface water c o2 in “strangelove ocean” after terminal cretaceous event.palaegeogr. palaeoclim. palaeoecol., 104, 229-237. holser, w.t., schönlaub, h.p., boeckelmann, k. & magaritz, m. (1991): the permian-triassic of the gartnerkofel-1 core (carnic alps, austria): synthesis and conclusions.abh. geol. b., a 45, 213-232. kajiwara, y., yakamita, s., ishida, k., ishiga, h. & imai, a. (1994): development of a largely anoxic stratified ocean and its temporary massive mixing at the permian/triassic boundary supported by the sulfur isotopic record.palaeogeogr. palaeoclim. palaeoecol., 111, 367-379. kramm, u. & wedepohl, k.h. (1991): the isotopic composition of strontium and sulfur in seawater of late permian (zechstein) age.chem. geol., 90, 253-262. magaritz, m. & holser, w.t. (1991): the permian-triassic of the gartnerkofel-1 core (carnic alps, austria): carbon and oxygen isotope variation.abh. geol. b., a 45, 149-163. magaritz, m., krishnamurthy, r.v. & holser, w.t. (1992): parallel trends in organic and inorganic carbon isotopes across the permian/triassic boundary.am. jour. sci., 292, 727-739. ramov©, a. (1986): marine development of the uppermost æaæar beds and the lowermost scythian beds.in: permian and permian-triassic boundary in the south alpine segment of the western tethys. excursion guidebook (ed. by the italian igcp 203 group), 39-42. sun, s., li, j., chen, h., peng, w., hsu, k.j. & shelton, j.w. (1989): mesozoic and cenozoic sedimentary history of south china.am. assoc. pet. geol. bull., 73, 1247-1269. tucker, m.e. (1990): geological background to carbonate sedimentation.in: tucker, m.e. & wright, v.p.: carbonate sedimentology. blackwell scientific publications, oxford, 28-69. wang, e., geldsetze, h.h.j. & kruose, h.r. (1994): permian-triassic extinction: organic δ1 3c evidence from british columbia, canada.geology, 22, 580-584. wolbach, w.s., roegge, d.r. & gilmour, i. (1994): the permian-triassic of the gartnerkofel-1 core (carnic alps, austria): organic carbon isotope variation.in: new developments regarding the kt event and other catastrophes in earth history. lp, contribution no. 825, lunar and planetary institute, houston, 138 p. yoichi, e. (1994): patterns and paleoenvironmental implications of end-permian extinction of rugosa in south china.palaeogeogr. palaeoclimatol. palaeoecol., 107, 165-177. zheng, y., hong-fei, h. & lian-feng, y. (1993): carbon and oxygen isotope event markers near the frasnian famenian boundary, luxin section, south china.palaeogeogr. palaeoclimatol. palaeoecol., 104, 97-104. manuscript received january 18, 1999. revised manuscript accepted may 28, 1999. 82 geologia croatica 52/1 273 halamic et al.indd 1. introduction the drava and sava rivers with their tributaries are the main drainage rivers in northwestern croatia (nwc) (fig. 1). the big settlements, cities and industrial plants are located alongside their streams. from its spring source in italy to the croatian border, the river drava flows through the alps in a relatively narrow river valley. after pohorje mt. in eastern slovenia it reaches the pannonian basin where it has excavated a relatively wide valley. the river frequently flooded in this area in heavy metal (as, cd, cu, hg, pb and zn) distribution in topsoil developed on alluvial sediments of the drava and sava rivers in nw croatia josip halamić, lidija galović and martina šparica geologia croatica 56/2 215–232 3 figs. 10 tabs. 6 pls. zagreb 2003 key words: geochemical mapping, topsoil, alluvial sediments, heavy metals, nw croatia. institute of geology, sachsova 2, p.o.box 268, hr-10000 zagreb, croatia; e-mail: jhalamic@igi.hr abstract in the region of north-western croatia (nwc) 328 topsoil samples were taken (from a depth of 0 to 25 cm). the composite samples were analyzed after near total decomposition (a hot acid mixture: hclo4–hno3–hcl–hf at 200°c) by icp–aes for as, cd, cu, pb and zn. hg was analysed by cold vapour aas. the following element concentration ranges were acquired: as 2–74 mg/kg (geometric mean 8 mg/kg), cd 0.4–9.4 mg/kg (geometric mean 0.4 mg/kg), cu 5–248 mg/kg (geometric mean 22 mg/kg), hg 5–4,535 mg/t (geometric mean 55 mg/t), pb 15–699 (geometric mean 32 mg/kg) and zn 28–1,432 (geometric mean 82 mg/kg). the analysis of the spatial distribution of heavy metals in nwc showed increased values of as, cd, hg and pb at mts. žumberak, medvednica, ivanščica and kalnik that originate mainly from natural sources (bedrock mineralizations and ore deposits). the cu and zn contents on mt. medvednica are only slightly less natural in origin. the high concentrations of copper on the slopes of mts. žumberak, medvednica, kalnik and in the nw part of hrvatsko zagorje are of anthropogenic origin and are related to wine-growing areas. in the sava river valley the average levels of hg, zn, as, cd, and pb are higher than the calculated baseline values (geochemical background) in the nwc while the cu values are equal to the baseline values. the higher values of as, cd, pb, and (in part) zn are for the most part of anthropogenic origin, and to a lesser extent of natural origin. the hg in the topsoil has a strong anthropogenic influence caused by mining upstream (litija) and by the city of zagreb’s urban area (fossil fuel combustion, traffic, electrolysis, diverse paints, pharmaceutical products, chlor-alkali industry and paper industry). the pedogenic profile shows that the content of cd, pb, cu and zn at a depth of 20 cm is almost half the content of the same elements found in the first two centimeters of the soil. at a depth of 60 cm, the concentrations are in the level of background values characteristic of the preindustrial era. when compared to the calculated baseline values, the contents of as, cd, cu and hg in the soils of the drava river valley are higher, while the pb and zn contents are anomalous. according to permitted concentrations of heavy metals for ecological food production prescribed by government regulations the contents of as, pb and zn in the topsoil on the drava alluvial sediment are too high. the cu concentrations are lower than the limit permitted by government regulation. the higher contents of mercury, although under the limit prescribed by government regulation, are an immediate consequence of fossil fuel combustion and traffic in the urban area of the city of varaždin. factor analysis and high correlation coefficients show a mutual connection of pb, zn and cd (pb and zn r=0.96; pb and cd r=0.80; zn and cd r=0.84). these 3 heavy metals show high positive factor loadings on the first factor (f1) which accounts for more than 58% of the data variability. the flood waters of the drava river were highly loaded with anthropogenic pb, zn and cd mainly as a consequence of mining, smelting and flotation activities upstream in the meža valley in the republic of slovenia and austria. also, they were additionally loaded with waste waters from upstream settlements. the soil profile shows that increasing depth results in the lowering of the pb, zn, cd and as content reaching the background level of that area at 80 cm depth. this suggests that the alluvial sediments of the preindustrial era lay deeper. the past. in spite of river banks built a few decades ago, it still floods in some of the lower parts along the river (kereša, 2002). the sava river arises in the alps in western slovenia, and it flows through a relatively narrow valley to the croatian border. after it reaches the southwest part the pannonian basin, the sava river flows in a wide river valley, and it has been known to flood lately during high water levels. the last great flood in the zagreb area happened in 1964, and some parts of the sava river valley downstream from zagreb occasionally flooded up until 1994. in the alps, the sava and drava rivers drain mountain massifs which also contain mineralisation and mineral deposits. exploitation of pb and zn ore deposits 216 geologia croatica 56/2 217halamić, galović & šparica: heavy metal (as, cd, cu, hg, pb and zn) distribution in topsoil... fig. 1 location map of investigated area with location of soil profiles p–1 (sava river valley) and p–2 (drava river valley). .--. • ... o ~v :1 ,. + • ,.. •• 'i •• """ j ...... ,r •• " .... rijeka bosnia and herzegovina ---. • ~v :1 ... o , . .. ,.. ..' •• """ j ...... ,r •• " .... rijeka bosnia and herzegovina 216 geologia croatica 56/2 217halamić, galović & šparica: heavy metal (as, cd, cu, hg, pb and zn) distribution in topsoil... in austria and in the vicinity of mežica in the eastern part of karavanke mt. (eastern slovenia), are particularly interesting when considering the content of heavy metals in soils in the alluvial plain of the drava river. these mining sites, along with mining waste dams and flotation devices were active until the last decade (štrucl, 1974; drovenik et al., 1980; souvent, 1994). three natural and one anthropogenic geochemical associations of pb and zn were found through geochemical investigation of soils, alluvial sediments and attic dust in the mežica area (šajn et al., 2000). the meža river, which is a tributary of the drava river, drains the ore-bearing area. the sava alluvial sediments reflect the influence of pb, zn, ba, and hg ore deposits in the litija region, samoborska gora mt. and medvednica mt. areas (mlakar, 1994; šinkovec, 1971; namjesnik et al., 1992). the content of heavy metals in a soil depends on the primary mineral composition of the parent material from which the soil was generated, as well as on the pedogenic processes and on the subsequent input of these elements to the soil (by wind, rain, ice, water etc.). heavy metals are most often bonded to clay minerals, micas, chlorite and mn–fe oxy-hydroxides. feldspars can also have higher contents of pb, zn and cu. the carriers of the greatest amounts of cu and zn can also be the main minerals of basic magmatic rocks (olivine, serpentine, pyroxene and amphibole). sulphide mineralization and weathering zones above them can be the source of an increased content of cu, zn, as, cd, hg and pb (adriano, 1986; rösler & lange, 1976; ruppert, 1991). the concentration of heavy metals in soils also largely depends on the source of the parent material. namely, the parent materials above the bedrock base have, as a rule, lower contents of these elements (with the exception of parent material in the weathering zones above ore deposits) than parent materials generated from fine grained alluvial sediments (the effect of over concentration through multiple redeposition of material in the river system) (miko et al., 2001). such natural, although relatively higher contents of heavy metals in soils above alluvial sediments, can in some regions be increased further due to anthropogenic input of these elements into the river system (waste waters from large settlements, waste disposal on the river coast, mining industry flotations), through atmospheric deposition of particles from urban sources (heating plants and other industry emission) and through the heavy traffic (sutherland & tolosa, 2001; fakayode & olu-owolabi, 2003). the purpose of this paper is to show the connection of the higher contents of heavy metals in topsoil to the historical mining activities upstream from the studied area, also to the agricultural activities (agrochemicals), and to the atmospheric deposition of these elements onto the topsoil (traffic, industry and other urban emissions) on the basis of the spatial distribution of heavy metals in the topsoil of the fluvial plains of the sava and drava rivers. 1.1. geology drava river valley todays flowline of the drava river is regulated through the building of dams and a few accumulation lakes, because of which there is no more flooding of larger areas outside the regulated streams. the drava river valley consists of two terraces and a recent floodplain. the terrace sediments, that were the source rocks for the parent material for soil generation, were deposited during the upper pleistocene and holocene. the terrace sediments consist of gravels, sands and of gravelly and silty sands. the gravel consists of quartz pebbles, metamorphic rocks, volcanics and subordinately of lithoclasts (cherts, breccia and carbonates). the sands consist of quartz (50–70%), feldspar (14–26%) muscovite (4–13%), rock fragments (1–3%) and carbonates (1–2%). a heavy mineral fraction (specific gravity >2.88) represents a relatively high percentage (11–38%, and up to 60% in some places) of the composition. the primary minerals of this fraction include garnet, epidote, amphibole, and to a lesser extent tourmaline, zircon, rutile, apatite, disthene, staurolite, chlorite and titanite (šimunić et al., 1981; marković & mioč, 1989; mioč & marković, 1998). the river bed and floodplain sediments consist of sands, muds, gravels and gravelly sands. they are generated through resedimentation of older fluvial sediments, and therefore have a similar mineral composition to the older terrace sediments. sava river valley the sava river alluvial sediments are also deposited on two terraces and a fluvial plain. the age of the sediments is upper pleistocene and holocene. the terrace sediments that comprise the greater part of the sava river valley consist primarily of gravels and sands, and secondarily of sandy and silty clays. the gravel pebbles are for the most part carbonate, then sandstone, chert, quartzite, volcanics, metamorphites and quartz. the composition of the sava river terrace pebbles differs completely from the composition of the drava river pebbles. the sands of the sava terraces consist of quartz, feldspar, muscovite and rock fragments. the content of quartz ranges from 64 to 88% and of the other components from 7 to 18%. the heavy mineral fraction consists of garnet, epidote, amphibole, pyroxene and subordinately of staurolite, disthene, rutile and titanite (šikić et al., 1979; basch, 1983). the composition of the heavy mineral fraction is similar to that of the drava river sands. the sediments of the floodplain areas and recent stream beds consist of coarse grained sandy–clayey silts, silty clays and thin layers of charcoal that were flooded in from slovenian coalmines (basch, 1983). 218 geologia croatica 56/2 219halamić, galović & šparica: heavy metal (as, cd, cu, hg, pb and zn) distribution in topsoil... the greater part of the light mineral fraction of these sediments consists of quartz (around 79%), and the heavy mineral fraction of epidote and garnet. 1.2. pedology fluvisols (fl) are developed on younger fluvial sediments of the drava river. eutric leptosols (lpe) are developed on the line from the state border up to varaždin, on the south side of the drava river, on older terraces rich in gravels. eutric cambisols (cme) prevail on the older terrace sediments on the north side of the drava river. eutric and dystric gleysols (gle and gld) are characteristic of the swampy parts of older alluvial terraces on the south side of drava river valley east of varaždin. fluvisols (fl) were developed on the fluvial sediments in the immediate vicinity of the sava river flowline, similar to the drava river. eutric cambisols (cme) were found on terrace sediments north and south of the sava river, on a line from the state border up to the southeast of zagreb. eutric and dystric gleysols (gle and gld) developed further to the southeast, where the sediments of the fluvial plain and terraces are fine grained and richer in ground and surface waters (fao, 1990; bogunović et al., 1996; martinović, 1997; špoljar, 1999). 2. materials and methods 2.1. sampling and sample preparation for the purpose of the geochemical map of the republic of croatia 328 topsoil samples (below amo or aoh horizons) from nwc were collected in a quadratic grid 5x5 km. the initial gridpoint for the geochemical mapping in croatia and slovenia was located in istria, croatia (pirc et al., 1991). the soil samples were taken at each sampling site from 5 shallow pits (0–25 cm depth) and one composite sample was prepared from each sample site. the detailed sampling procedure was given in guidelines for the geochemical mapping of croatia (halamić et al., 20001). these guidelines were based on previous works of pirc et al. (1991), prohić et al. (1997, 1998), peh & miko (19992), halamić & galović (19993), and differ only slightly from the recommendation given by darnley et al. (1995) and salminen et al. (1998). the collected samples were air dried and sieved to pass the 63 µm screen. 2.2. analytical methods, accuracy and precision after sieving, a homogenized 2 g sample was near totally decomposed in a hot acid mixture hclo4–hno3– hcl–hf at 200°c. the icp–aes analyses were performed in acme laboratories in vancouver (canada) for as, cd, cu, pb and zn. volatilization during fuming may result in some loss of as. the content of mercury was analysed with faas after aqua regia digestion. accuracy of the analyses was controlled with the aid of certified geological reference materials (usgs: gxr–2, gxr–5, and sjs–1). the accuracy for most elements analyzed in reference soil materials is in the range of ±15% of the certified values, except for cd (±23%). the precision of the analyses was determined by repeated analysis of both certified reference samples and randomly selected soil samples (13 duplicated samples), the resulting coefficient of variation is, on average approximately 5% (halamić & galović, 19993). 2.3. statistical treatment and graphic presentation the evaluation of basic statistical parameters for all elements was performed, after log10 transformation, on the analytical data from the whole database for nwc (n=328) and separately for each river valley (drava n=21, sava n=18). these parameters are given in tables 1, 3 and 7. also the non-parametric distributions of each element are given as the 10th, 25th, 50th, 75th, 90th, 95th, 98th and 99th percentile values, which are present as elemental concentration distribution contour boundaries on the maps (plates 1–6). the coefficents of correlation of each river valley are given in tables 4 and 8. the r-mode factor analysis was used as a tool of data reduction, with the purpose of a clearer insight into the basic relationships among variables. it was performed separately for the data set of each river valley, with the aim to observe similarites of geochemical behaviour of the analysed elements and to allow a more straightforward insight into the structure of the data. the eigenvalue of factors and factor loadings are given in tables 5, 6, 9 and 10. all statistical analyses were performed with the statistica software (ver. 5.1). the single-element geochemical maps were produced with the surfer mapping software (ver. 7.0). griding was performed by linear kriging (isaaks & sirvastava, 1989) with grid cell resolution of 2x2 km. 1 halamić, j., miko, s., peh, z. & galović, l. (2000): upute za izradu “osnovne geokemijske karte republike hrvatske” [instructions for production of “the basic geochemical map of the republic of croatia” – in croatian].– unpubl. report, archive of the institute of geology, zagreb, 51/2000, 22 p. 2 peh, z. & miko, s. (1999): geokemijski atlas srednje i južne dalmacije [geochemical atlas of central and southern dalmatia – in croatian].– institute of geology, open file report, 115/1999, zagreb, 102 p. 3 halamić, j. & galović, l. (1999): geokemijske karte sjeverozapadne hrvatske [geochemical maps of northwestern croatia – in croatian].– unpubl. report, archive of the institute of geology, zagreb, 72/99, 111 p. 218 geologia croatica 56/2 219halamić, galović & šparica: heavy metal (as, cd, cu, hg, pb and zn) distribution in topsoil... 3. results and discussion the basic statistical parameters (mean, geometric mean, median, maximum and minimum of the measured values and standard deviation) for nwc are given in table 1. for comparison, the data for the slovenian territory (pirc, 1993; andjelov, 1994; šajn et al., 2000), have been added into that table. the statistical distribution of the elements is graphically represented as a single-element maps (plates 1–6). 3.1. northwestern croatia (nwc) arsenic the measured content of as in the topsoil of nwc varies from 1.8 to 74 mg/kg with a mean value of 10 mg/ kg (table 1). concentrations above the recommended values (table 2) were registered at individual locations on mts. žumberak, medvednica, kalnik and ivanščica and in the drava and sava river valleys (plate 1). higher values at the first four locations are most likely a consequence of the bedrock composition or of mineral deposits, respectively. however, a higher concentration of as in the soils of the međimurje region can also be a consequence of intensive agricultural activity (pesticides). cadmium the cd content in the soils of nwc varies from <0.4 (below detection limit) up to 9.4 mg/kg with a mean value of 0.5 mg/kg (table 1). around 56% of all measured values are below the detection limit. half the value of the detection limit (0.2 mg/kg) was taken as a minimum value for statistical analysis of these samples. over 95% of topsoil samples in nwc have a cadmium content lower than the maximum content prescribed by the law for agricultural soils (table 2) (narodne novine, 1992, 2001). concentrations above the recommended values were registered on mts. žumberak, ivanščica, kalnik and in the drava river valley (plate 2). the anomalies on mts. žumberak, ivanščica and kalnik are of natural origin (mineralization) while the ones in the drava river valley are for the most part a consequence of mining activities upstream. copper the copper content in the nwc soils varies from 5 to 248 mg/kg with a mean value of 25 mg/kg (table 1). the high concentrations of copper in the investigated area are mainly of anthropogenic origin in relation to agricultural activities, especially wine-growing (fungicides based on copper sulphate). these concentrations are a characteristic of the wine growing areas of mts. žumberak, medvednica, kalnik and in the western part of the hrvatsko zagorje region (plate 3). the anomaly on medvednica mt. north of zagreb (plate 3) is however, the consequence of ore mineralization in that area. mercury the mercury content ranges from <10 mg/t, which is the lowest detection value, up to 705 mg/t, with the exception of a very high concentration measured on top of mt. kalnik (4,535 mg/t) and has a mean value of 94 mg/t (table 1). only 1% of analysed samples from nwc have values below the detection limit. relatively high values of hg content were registered along the sava river, on the medvednica, samoborska gora, and ivanščica mts. and in the zagreb and varaždin city areas, but the values were significantly below the maximum allowed (plate 4, table 2; narodne novine, 1992, 2001). high contents on mts. žumberak, kalnik and ivanščica are the consequence of ore mineralization, while the anomalies in soils developed on alluvial sediments and in urban areas are of anthropogenic origin. lead the concentration of lead in nwc ranges from 15 to 385 mg/kg, with a mean value of 39 mg/kg (table 1). anomalous concentrations follow the course of the alpine drava river and are in relation to its fluvial areas. their origin could be both anthropogenic and natural. the relatively higher values on mts. žumberak, medvednica, kalnik and ivanščica are a consequence of lead mineralization in that area (plate 5). other regions of nwc have pb values significantly lower than the maximum values prescribed by law (table 2). slo nwc (n=819) (n=328) mean mean geo. mean median min. max. stdv. as (mg/kg) <5 10 8 8 2 74 7.86 cd (mg/kg) 0.5 0.5 0.4 0.2 <0.4 9.4 0.84 cu (mg/kg) 23 25 22 22 5 248 20.19 hg (mg/t) 160 94 55 60 5 4535 256.50 pb (mg/kg) 34 39 32 29 15 699 54.26 zn (mg/kg) 104 101 82 77 28 1432 123.24 table 1 basic statistical parameters for topsoil in northwestern croatia (nwc) (slo = data for slovenian soils from pirc, 1993; andjelov, 1994; šajn et al., 2000; geo. mean = geometric mean; stdv. = standard deviation). 220 geologia croatica 56/2 221halamić, galović & šparica: heavy metal (as, cd, cu, hg, pb and zn) distribution in topsoil... zinc the measured values of zn in nwc range from 28 to 1,432 mg/kg with a mean value of 101 mg/kg (table 1). around 10% of the samples have zinc concentrations higher than those legally allowed (>300 mg/kg) (narodne novine, 1992). all these anomalies are in soils developed on alluvial sediments of the drava river (plate 6). higher contents have been measured in samples from the sava river valley, downstream from zagreb, in the lonja river valley, in the central part of the krapina river flowline, and also in the valley of the horvatska river in the hrvatsko zagorje region. these concentrations could also indicate anthropogenic dispersion of zn in the environment. this is most visible in parts of posavina with intense agriculture and an increased use of artificial fertilizers. namely, some artificial fertilizers can contain up to 0.1% zn (brehler & wedepohl, 1972). higher concentrations on mts. ivanščica and kalnik and in the southeastern part of samoborska gora mt. are probably a consequence of zn mineralization, as in the case of medvednica mt. the topsoil developed on sava and drava alluvial sediments has higher contents of these heavy metals than concentrations in the region of nwc (halamić & galović, 19993, 20004) or the concentrations in topsoil of the republic of slovenia (pirc, 1993; andjelov, 1994). therefore their distribution is described in detail below. 3.2. sava river valley the basic statistical parameters for the topsoil of the sava river valley are shown in table 3. compared with topsoil developed in the drava river valley, the average content of almost all heavy metals in sava valley topsoil is lower, with the exception of hg (tables 3 and 7). the content of as, cd, hg and pb in the sava river valley is higher, the cu content is lower and the zn content is average when put in relation to the average content of heavy metals in normal soils worldwide. the average contents of hg, zn, as, cd, and pb are higher than calculated baseline contents (geochemical background) in topsoil of nwc. the cu values are equal to the baseline values of this area. the geochemical background levels for the nwc were calculated with the aid of iterative 2σ-technique (matschullat et al., 2000). the calculated values of heavy metals in the sava river valley topsoil are below the limit prescribed by government regulations for the ecological production of plants in croatia (narodne novine, 2001) (table 2). the only exception is arsenic which is on the border of the legally prescribed value. also, as, cd, cu, pb and zn show no relevant deviation from their average values, i.e. they do not show any anomalous values. there are two possible reasons for the higher contents of as, cd, pb and in part of zn. mainly it is a consequence of anthropogenic input into the soil through airborne distribution of the material (atmospheric deposition – combustion of fossil fuels, industry, traffic), or a reflection of the historical mining activities in the broader region surrounding zagreb in the past (mts. samoborska gora and medvednica). the higher contents of heavy metals in soils of the fluvial valley downstream from zagreb are related to more clay rich soils. the heavy metals were transported in suspension and then sedimented during floods that were relatively common in this area before the appropriate dams were built. a lesser part can be related to pollution through agrochemicals (pesticides etc.) (romić & romić, 2003). the content of mercury in the sava river valley topsoil shows higher, and in part anomalous values, when compared to the baseline values of nwc. the highest values were registered after the sava rivers’ recourse into croatia and in the zagreb city area which indicates the anthropogenic origin of the mercury. the high content of hg in the topsoil of the fluvial sediments after the slovenian–croatian border is mainly light structure soils, heavier and soils for the ecological skeletal soils and soils heavy structure agricultural production with a low humus soils and soils of plants content with a high humus content (nn 1992) (nn 1992) (nn 2001) as (mg/kg) 20 30 10 cd (mg/kg) 1 2 0.8 cu (mg/kg) 60 100 50 hg (mg/kg) 1 2 0.8 pb (mg/kg) 100 150 50 zn (mg/kg) 200 300 150 table 2 prescribed concentrations of heavy metals in agricultural soils for normal and ecological production (narodne novine, 1992, 2001) (analysed dry soil extracted by aqua regia). 4 halamić, j. & galović, l. (2000): geokemijske karte sjeverne hrvatske [geochemical maps of northern croatia – in croatian].– unpubl. report, archive of the institute of geology, zagreb, 72/2000, 104 p. 220 geologia croatica 56/2 221halamić, galović & šparica: heavy metal (as, cd, cu, hg, pb and zn) distribution in topsoil... the consequence of industrial pollution of the sava river, and to a lesser extent the sutla and krapina rivers, by waste waters. the pollution of the river sava is caused by mining and smelting activities in slovenia (litija). around 150 tons of hg were excavated in litija (mlakar, 1994). in the zagreb city area, mercury emanates into the air mainly from industrial plants. sources of airborne mercury are fossil fuel combustion, traffic, electrolysis, diverse paints, pharmaceutical products, chlor-alkali and paper industries (miko et al., 1992; palinkaš et al., 1996). research on the mercury content in urban soils along the city’s main roads and its periphery, shows concentrations twice as high as background values (namjesnik et al., 1992). pearson’s product moment correlation coefficient shows strong correlations between zn and cu (r=0.90), zn and pb (r=0.78), zn and cd (r=0.74), cu and cd (r=0.74) and hg and cd (r=0.73) at p<0.05 (see table 4). arsenic shows no correlation to any of the heavy metals. such high coefficients of correlation indicate the source of zinc, lead, copper and cadmium from the mining and smelter industry upstream. a lesser proportion of the mercury content is probably also from the same source, while the remaining bulk concentration could be a consequence of atmospheric pollution. this is also indicated by the results of factor analysis as shown in tables 5 and 6. mercury is grouped in the first factor that explains around 66% of the total variance. arsenic is included in the second factor and shows no significant correlation to any of the other heavy metals, indicating that it originates from a different source. the higher concentrations in the western part of zagreb are of anthropogenic origin (airborne mercury), while its origin in agricultural soils downstream form zagreb could be a consequence of agricultural activities. cu and zn are grouped into the third factor which explains only around 10% of the total variance. their origin could be related to mining and smelting activities in the mountain areas of croatia around the sava river valley (mt. samoborska gora – rude; mt. medvednica) and also slovenia (litija). a pedogenic profile southwest of zagreb was selected for detailed analysis on the basis of the spatial distribution of heavy metals in the fluvial sediments of the river sava. the depth of the profile was 121 cm (fig. 2). seven samples were taken through the whole profile. the analysis showed that the surface horizon is enriched with as and also all other analysed heavy metals, as opposed to lower horizons. the cd, pb, cu and zn content at a depth of 20 cm is almost half the content of the same elements at a depth of 2 cm. the concentrations decrease with depth, and at 60 cm reach “background” values characteristic of the pre-industrial era. only the as content slightly increases with depth and reaches its maximum at 60 cm. baseline values are recorded at 90 cm (fig. 2). sava (n=18) mean geo. mean median min. max. stdv. as (mg/kg) 10 9 9 5 18 4.20 cd (mg/kg) 0.5 0.4 0.5 0.2 0.8 0.19 cu (mg/kg) 24 23 23 12 35 7.39 hg (mg/t) 111 79 77 10 450 108.16 pb (mg/kg) 34 33 34 18 58 11.12 zn (mg/kg) 91 88 90 53 135 23.59 table 3 basic statistical parameters for topsoil in the sava river valley (geo. mean = geometric mean). factor total % of var. cumul.% 1 3.96 66.01 66.01 2 0.79 13.14 79.14 3 0.64 10.69 89.83 table 5 eigenvalues of factors for sava river valley topsoils. factor factor factor 1 2 3 cu 0.20 0.24 0.90 pb 0.48 0.13 0.70 zn 0.24 0.21 0.92 as 0.14 0.96 0.25 cd 0.60 0.20 0.59 hg 0.96 0.11 0.22 expl.var. 1.69 1.09 2.61 prop.totl. 0.28 0.18 0.43 table 6 factor loadings for sava river valley topsoils (varimax normalized; extraction: principal components; marked loadings are >0.5). cu pb zn as cd hg cu 1 pb 0.66 1 zn 0.90 0.78 1 as 0.47 0.39 0.47 1 cd 0.74 0.57 0.74 0.41 1 hg 0.43 0.62 0.46 0.30 0.73 1 table 4 correlation coefficients for topsoil in the sava river valley (correlation significant at p<0.05). 222 geologia croatica 56/2 223halamić, galović & šparica: heavy metal (as, cd, cu, hg, pb and zn) distribution in topsoil... by the croatian government regulation (narodne novine, 2001) the contents of as, pb and zn in topsoils on the drava alluvial sediment are too high (tables 2 and 7). however, different methods of sample preparation (total digestion vs. aqua regia, and <2 mm vs. 0.063 mm granulometric fraction) influenced certain differences in the measured contents. the concentrations of copper in the drava river valley are lower than those prescribed by government regulation and show no correlation to any other elements (table 8). copper shows a high positive loading on the second factor (f2) which accounts for over 16% of the data variability. the increased contents of arsenic are in some places higher than those prescribed by government regulation for the ecological production of food (table 2), but are still lower than the anomalous values measured in topsoil that developed on the drava river alluvial sediments. similarly to cu, as shows no direct correlation to any other heavy metal. the factor analysis shows high positive loadings of this element on the fourth factor (f4) (table 10). such a result indicates fig. 2 vertical distribution diagram of heavy metals in topsoil in sava river valley – profile p–1 (for location see fig. 1). 3.3. drava river valley the topsoil developed on drava alluvial sediments has higher concentrations of pb, zn and as in relation to the other investigated areas in nw croatia (miko et al., 2001; halamić & galović, 19993, 20004). the basic statistical parameters for the analysed samples are given in table 7. the measured values of heavy metals in these soils are higher for as, cd, and hg, and anomalous for pb and zn, when related to the values acquired for the nwc region (table 1). only the cu values are lower in relation to nwc (tables 1 and 7). all the contents of heavy metals in soils of the drava river valley are higher, while the lead and zinc values are anomalous when related to calculated baseline values. when comparing the measured contents in soils of the drava river valley to the average global levels, it is obvious that the contents of as, cd and hg are higher and the pb and zn contents are significantly higher, while the cu content is lower. according to permitted concentrations of heavy metals for ecological food production prescribed drava (n=21) mean geo. mean median min. max. stdv. as (mg/kg) 12 9 11 2 28 8.10 cd (mg/kg) 0.8 0.4 0.2 0.2 4.5 1.28 cu (mg/kg) 26 25 26 14 48 8.81 hg (mg/t) 77 56 55 25 470 116.20 pb (mg/kg 76 49 41 22 382 109.07 zn (mg/kg) 194 125 96 61 974 282.27 table 7 basic statistical parameters for topsoil in the drava river valley (geo. mean = geometric mean). 222 geologia croatica 56/2 223halamić, galović & šparica: heavy metal (as, cd, cu, hg, pb and zn) distribution in topsoil... a different source for both heavy metals. increased values of as are found in intensively cultivated agricultural areas of the north bank of the river drava (plate 1). this indicates its anthropogenic origin in the soil. the higher contents of mercury, although under the limit prescribed by government regulation, are an immediate consequence of fossil fuel combustion and traffic in the urban area of varaždin. the factor analysis shows mercury grouping in the third factor (f3) which accounts for about 13% of the data variability (table 10). lead, zinc, and in part cadmium, from the drava river valley topsoil have anomalous values over the limit prescribed by government regulation for ecological agricultural production. the interrelation of these elements is showed by high correlation coefficients (pb and zn r=0.96; pb and cd r=0.80; zn and cd r=0.84 – table 8) and by the results of factor analysis. these three heavy metals show high positive factor loadings on the first factor (f1) which accounts for more than 58% of the data variability (tables 9 and 10). since the marginal areas of the drava river valley have no known natural polluters, the sources of the high values of heavy metals in this topsoil have to be searched for upstream. the flood waters of the drava river were highly loaded with anthropogenic pb, zn and cd as a consequence of mining, smelting and flotation activities upstream in the meža river valley in the republic of slovenia (souvent, 1994; šajn et al., 2000) and austria. the soil profile shows that increasing depth results in the lowering of pb, zn, cd and as content reaching the background level for that area at 80 cm depth. this suggests that the alluvial sediments of the pre-industrial era lay deeper and that the soil contamination with heavy metals continuously increases up to recent soil horizons (fig. 3). 4. conclusions spatial distribution of heavy metals in topsoils of nwc shows that the higher to anomalous values of cu in nwc are, for the most part, related to winegrowing areas, that is, to the anthropogenic input of this metal into the topsoil. the anomalous values of as and cd are mainly of natural origin (mineralization). only some of the as anomalies are of anthropogenic origin (međimurje region – agriculture), and anthropogenic cd is related only to the drava river fluvial valley. high contents of hg on mts. kalnik and ivanščica are of natural origin, whilst the source is of anthropogenic origin in the zagreb and varaždin city areas as well as in the drava river valley. analysis of the spatial distribution of heavy metals in the sava river valley showed no anomalous values of analysed heavy metals, with the exception of higher hg contents in the zagreb city area. the correlation fig. 3 vertical distribution diagram of heavy metals in topsoil in drava river valley – profile p–2 (for location see fig. 1). cu pb zn as cd hg cu 1 pb 0.35 1 zn 0.37 0.96 1 as 0.41 0.56 0.46 1 cd 0.20 0.80 0.84 0.38 1 hg 0.23 0.47 0.47 0.19 0.27 1 table 8 correlation coefficients for topsoils in the drava river valley (correlation significant at p<0.05). 224 geologia croatica 56/2 225halamić, galović & šparica: heavy metal (as, cd, cu, hg, pb and zn) distribution in topsoil... coefficient indicates a significant correlation of hg to cd and pb (r=0.73 and r=0.62 respectively) (table 4). cd has high correlations to cu and zn (r=0.74 and r=0.74 respectively) that are mostly a consequence of mining and smelting activities from upstream areas. the factor analysis showed grouping of mercury in the first factor that explains over 66% of the total variance. all this leads to the conclusion that only a small part of the hg content in the sava river valley topsoil is caused by upstream mining and smelting activities, and that a greater amount is caused by fossil fuel combustion and industrial plants from the zagreb city area (airborne pollution) (namjesnik et al., 1992). the drava river valley area has anomalous values of pb, zn and cd when compared to the sava river valley. as and hg, show only local anomalous deviation from average values, while the cu concentrations are within the normal range. these three elements showed no significant correlation to any other analysed heavy metals, which means that their source is different from the source of pb, zn and cd. higher contents of as were found in agricultural areas ne of varaždin. they are probably a consequence of the treatment of these agricultural areas with agrochemicals (pesticides that contained as). the anomaly of hg is related to the varaždin city area and is a result of the pollution of the topsoil through atmospheric deposition. pb, zn and cd showed a significant correlation to one another (table 8). these three elements were also grouped in the first factor (f1) (table 10), characteristic of the anthropogenic input of these elements in the soil, and which also explains over 58% of the total variance. the soils of the drava river valley generated from fluvial sediments that were in part naturally enriched with heavy metals (mineralization of pb and zn upstream in austria and slovenia). furthermore, the river drava flooded regularly until recently, carrying with it heavy metals that were washed down from pb and zn mines (mining waste dams, firm and liquid smelter waste, etc.). after flooding the heavy metals were washed out from the flood sediments and placed into the topsoil. acknowledgements this study was funded by the ministry of science and techology of the republic of croatia (project number 0181006) the authors are much obligated to the reviewers professor reijo salminen (geological survey of finland – espoo) and professor goran durn (faculty of mining, geology and petroleum engineering – zagreb) for critical comments that have improved this manuscript. 5. references adriano, d.c. (1986): trace elements in the terrestrial environment.– springer verlag, new york, berlin, heidelberg, tokyo, 533 p. andjelov, m. (1994): rezultati radiometričnih in geokemičnih meritev za karto naravne radioaktivnosti slovenije [results of radiometric and geochemical measurements for map of the natural radioactivity of slovenia – in slovenian].– geologija, 36, 223–248, ljubljana. basch, o. (1983): osnovna geološka karta sfrj 1:100.000. tumač za list ivanić grad l33-81 (basic geological map of sfry, 1:100,000. explanatory notes for ivanić grad sheet).inst. za geol. istraž. zagreb (1980), savezni geol. zavod beograd, 66 p. bogunović, m., vidaček, ž., racz, z., husnjak, s. & sraka, m. (1996): namjenska pedološka karta, mjerilo 1:300.000 [applied pedological map, scale 1:300,000 – in croatian].– agronomski fakultet sveuč. u zagrebu, zavod za pedologiju, zagreb. brehler, b. & wedepohl, k.h. (1972): zinc.– in: wedepohl, k.h. (ed.): handbook of geochemistry. springer verlag, berlin, heidelberg, new york, 30–a– 1–30–o–2. darnley, a.g., björklund, a., bolviken, b., gustavsson, n., koval, p.v., plant, j.a., steenfelt, a., tauchid, m., xie, x., garret, r.g. & hall, g.e.m. (1995): a global geochemical database for environmental and resource management. final report of igcp project 295.– unesco publishing, paris, 122 p. factor factor factor factor 1 2 3 4 cu 0.14 0.97 0.09 0.18 pb 0.87 0.15 0.27 0.31 zn 0.91 0.19 0.27 0.18 as 0.27 0.19 0.06 0.94 cd 0.95 0.03 0.03 0.11 hg 0.22 0.09 0.97 0.06 expl.var. 2.61 1.05 1.09 1.06 prop.totl. 0.43 0.17 0.18 0.18 table 10 factor loadings in topsoil of the drava river valley (varimax normalized; extraction: principal components; marked loadings are >0.5). factor total % of var. cumul.% 1 3.48 58.07 58.07 2 0.96 16.04 74.11 3 0.82 13.63 87.75 4 0.54 9.03 96.78 table 9 eigenvalues of factors for drava river valley topsoils. 224 geologia croatica 56/2 225halamić, galović & šparica: heavy metal (as, cd, cu, hg, pb and zn) distribution in topsoil... drovenik, m., pleničar, m. & drovenik, f. (1980): nastanek rudišč v sr sloveniji [formation of mineral ore deposits in sr slovenia – in slovenian].– geologija, 23/1, 1–157, ljubljana. fakayode, s.o. & olu-owolabi, b.i. (2003): heavy metal contamination of roadside topsoil in osogbo, nigeria: its relationship to traffic density and proximity to highways.– env. geol., 44/2, 150–157. fao (1990): soil map of the world. revised legend.– world soil resources reports, 60, fao/unesco/isric, rome. isaaks, e. & sirvastava, r. (1989): an introduction to applied geostatistics.– oxford university press, new york, 561 p. kereša, z. (2002): poplave u našem dvorištu [floods in our backyard – in croatian].– izložba hrvatskih voda. sažetak, 1–2, varaždin. marković, s. & mioč, p. (1989): osnovna geološka karta sfrj 1:100.000. tumač za list nađ kanižu l33-58 (basic geological map of sfry, 1:100.000. explanatory notes for sheet nađ kaniža).inst. za geol. istraž. zagreb (19851986), savezni geol. zavod beograd, 36 p. martinović, j. (1997): tloznanstvo u zaštiti okoliša [soil science in protection of the environment – in croatian].– državna uprava za zaštitu okoliša, zagreb, 288 p. matschullat, j., ottenstein, r. & reimann, c. (2000): geochemical background – can we calculate it?– env. geol., 39/9, 990–1000. miko, s., durn, g., palinkaš, a.l., mashyanov, n., namjesnik, k. & ilyin, y. (1992): distribution of mercury and aerosols of lead and cadmium in the atmosphere of zagreb.– rud. met. zbornik, 39/3–4, 369–387, ljubljana. miko, s., halamić, j., peh, z. & galović, l. (2001): geochemical baseline mapping of soil developed on diverse bedrock from two regions in croatia.– geol. croatica, 54/1, 53–118. mioč, p. & marković, s. (1998): osnovna geološka karta republike slovenije i republike hrvatske 1:100.000. tumač za list čakovec l33-57 (basic geological map of the republic of slovenia and the republic of croatia, 1:100.000. explanatory notes for sheet čakovec).inst. za geol. istraž. zagreb, inšt. za geol., geotehn. in geofiz. ljubljana, 69 p. mlakar, i. (1994): o problematiki litijskega rudnega polja [on problematics of the litija mining field – in slovenian].– geologija, 36, 249–338, ljubljana. namjesnik, k., palinkaš, l.a., miko, s., durn, g., polić, d. & kvrgnjaš, l. (1992): lead, zinc, nickel and mercury in soil along road sides and of some rural and urban parts of zagreb, croatia.– mining and metallurgy quarterly, 39/1–2, 93–112, ljubljana. narodne novine (1992): pravilnik o zaštiti poljoprivrednog zemljišta od onečišćenja štetnim tvarima [regulation on protection of agricultural lands from pollution by potentially toxic substances – in croatian].– vlada republike hrvatske, ministarstvo poljoprivrede i šumarstva, 15/92, zagreb. narodne novine (2001): pravilnik o ekološkoj proizvodnji u uzgoju bilja i u proizvodnji biljnih proizvoda [regulation on ecological production of plants and products of plant cultivation – in croatian].– vlada republike hrvatske, ministarstvo poljoprivrede i šumarstva, 91/01, zagreb. palinkaš, a.l., namjesnik, k., miko, s., durn, g. & pirc, s. (1996): distribution of mercury, lead and cadmium in zagreb city soils.– in: richardson, m. (ed.): environmental xenobiotics. taylor & francis, london, 355–374. pirc, s. (1993): regional geochemical surveys of carbonate rocks – final report; usg project number: jf 881–0.– poročilo, knjižnica odseka za geologijo, ntf, ljubljana, 30 p. pirc, s., mcneal, m.j., lenarčič, t., prohić, e. & svrkota, r. (1991): geochemical mapping of carbonate terrain.– bull. inst. mettal. min., applied earth sci., 100, b74–b83. prohić, e., hausberger, g. & davis, j.c. (1997): geochemical patterns in soils of the karst region, croatia.– j. geochem. explor., 60, 127–138. prohić, e., peh, z. & miko, s. (1998): geochemical characterization of karst polje – an example from sinjsko polje, croatia.– environmental geology, 33/4, 263–273. romić, m. & romić, d. (2003): heavy metals distribution in agricultural topsoils in urban area.– env. geol., 43, 795–805. rösler, h.j. & lange, h. (1976): geochemische tabellen [geochemical tables – in german].– veb deutscher verlag, leipzig, 674 p. ruppert, h. (1991): natürliche spurenmetallgehalte im boden und ihre anthropogene überprägung [natural contents of trace elements in soils and their anthropogenic overprint – in german].– mitt. österr. geol. ges., 83 (1990), 243–265. salminen, r., tarvainen, t., demetriades, a., duris, m., fordyce, f.m., regorauskiene, v., kahelin, h., kivisilla, j., klaver, g., klein, h., larson, j.o., lis, j., locutura, j., marsina, k., mjartanova, h., mouvet, c., o’connor, p., odor, l., ottonello, g., paukola, t., plant, j.a., reimann, c., schermann, o., siewers, u., steenfelt, a., van der sluys, j., de vivo, b. & williams, l. (1998): foregs geochemical mapping – field manual.– geological survey of finland, espoo, 36 p. souvent, p. (1994): rudnik mežica nekoč, danes in jutri [mežica mine in the past, today and in the future – in slovenian].– in: lah, a. (ed): okolje v sloveniji. zbornik, tehniška založba slovenije, 533–541, ljubljana. sutherland, r.a. & tolosa, c. (2001): variation in total and extractable elements with distance from roads in an urban watershed, honolulu, havaii.– water air soil pollut., 127, 315–338. šajn, r., gosar, m. & bidovec, m. (2000): geokemične lastnosti tal, poplavnega sedimenta ter stanovanjeskega in podstrešnega praha na območju mežice [geochemical properties of soils, flood sediments and attic dust in the 226 geologia croatica 56/2 227 area of mežica – in slovenian].– geologija, 43/2, 235– 245, ljubljana. šikić k., basch, o. & šimunić a. (1979): osnovna geološka karta sfrj 1:100.000. tumač za list zagreb l33-80 (basic geological map of sfry, 1:100.000. explanatory notes for sheet zagreb).inst. za geol. istraž. zagreb (1972), savezni geol. zavod beograd, 66 p. šimunić, an., pikija, m., hećimović, i. & šimunić, al. (1981): osnovna geološka karta sfrj 1:100.000. tumač za list varaždin l33-69 (basic geological map of sfry, 1:100.000. explanatory notes for sheet varaždin). inst. za geol. istraž. zagreb, savezni geol. zavod beograd, 66 p. šinkovec, b. (1971): geologija ležišta željezne i bakrene rude u rudama kraj samobora [geology of fe and cu ore deposit in rude near samobor – in croatian].– geol. vjesnik, 24, 165–181. špoljar, a. (1999): fao klasifikacija s bazom podataka za pedološku kartu republike hrvatske sitnog mjerila [fao classification with data base for the small scale pedological map of the republic of croatia – in croatian].– unpubl. msc thesis, university of zagreb, 75 p. štrucl, i. (1974): nastanek karbonatnih kamenin in cinkovo svinčeve rude v anizičnih plasteh tople [origin of carbonate rocks and zn-pb ore in anisic deposits of topla – in slovenian].– geologija, 17, 299–399, ljubljana. manuscript received april 17, 2003. revised manuscript accepted november 04, 2003. 226 geologia croatica 56/2 227 plate 1 spatial distribution map of arsenic in topsoil of the north-western croatia with box-whiskers diagram and histogram. halamić, galović & šparica plate 1 228 229 plate 2 spatial distribution map of cadmium in topsoil of the north-western croatia with box-whiskers diagram and histogram. geologia croatica 56/2plate 2 228 229 plate 3 spatial distribution map of copper in topsoil of the north-western croatia with box-whiskers diagram and histogram. halamić, galović & šparica plate 3 230 231 plate 4 spatial distribution map of mercury in topsoil of the north-western croatia with box-whiskers diagram and histogram. geologia croatica 56/2plate 4 230 231 plate 5 spatial distribution map of lead in topsoil of the north-western croatia with box-whiskers diagram and histogram. halamić, galović & šparica plate 5 232 plate 6 spatial distribution map of zinc in topsoil of the north-western croatia with box-whiskers diagram and histogram. geologia croatica 56/2plate 6 geol. croat. 49/2 171 177 zagreb 1996 professional paper current trends and optimal taxation arrangements in the international petroleum industry roger m. nellist kc,y words: exploration and production of oil and gas, legal, economic and political conditions, republic of croatia, international participation . abstract in order (0 allrael the interest of international oil companies and (0 protect croatia' s legitimate national interests in the opening of this key upstream petroleum secior (exploration hnd developmellt), a dcli­ !lilian and an international clarification of legal, economic and po liti­ cal conditions is needed, as well as knowledge of lcchnical-gcologic­ exploration characteristics of exploration areas. the need 10 do so, in (he eyes of interested imernalional factors, emerges from the incom ­ pl e teness of exi sting legal , and parlly financial regulations, and diffi­ culties in following up their amendments in recent years. croatia's l\,tining law with s upplemental acts encompasses too broad a range o f min e ral resources, especially in the part treating production and mark e t. explanation of ilinbiguities connected to guarantees of exploitation rights to the company that has made the discovcry by investing the ri sk money, as we ll as removal of anacijronous obligati ­ on s of the company to participate in flirt her explorations is necessary. on th e other hand, the reponing requirements have to be more comprehensive, detailed and rigorous, especially in the definition of income and expenditures . some of the exi sting conditions for joint venture s are too " generous", due to the liability of the national oil company to cover the production tax, especially in tile areas with already establi shed production. due to the aforementioned, and in orde r to exclude som e overcomplicaled production-sharing types of arrangement s, a modern fiscal regime for the upstream sector of petroleum industry in question is suggested and explained in detail. [n thi s fiscal package, the cxisting system is augmented wit h an addi ­ tional profit tax. the government take, thereby automatically grows in th e case of s ubswll1ial additional profit. at (he same time, some marginally economic field s wou ld pay only revenue taxes at a modest rate. a foreign currency fiscal regime specially designed for the oil indu stry is al so suggeslcd. the definition and an internationa1 promo­ tion of the role of a national oil company as an independent and directly accessible partner of international companies, and as a meet­ ing point of domestic private initiatives that are gaining more impor­ t<llke is an important politic;11 decision. solution of this set of condi­ tions would enable croatia to aggressively implement an effective international oil promotion campaign. 1. introduction my participation in [his first international sympo­ sium or petroleulll geology has been facilita ted by the croatian academy or sciences and arts, scientific council for petroleum, and ina-naftaplin. in exprcs­ sing my gratitude to the symposium programme coill­ mittec ror their invitation, 1 would like 10 sound a spcproceedings kljucne rijeci : istrazivanje i proizvodnja nane i plina, pravni, ekonomsk i i pol iti cki uvjeti, republika hrvatska, medunarodno sudjelovanje. saietak radi pobude interesh medunarodnih naftnih kompanija i zastite legitimnih hrvatskih nacionalnih in teresa u otvaranjll ovog kljucnog dijela naftne industrije (is!fazivanja i proizvodnje) , potrebno je defini­ rati i na medunarodnom planu razjasniti pravne, ekonoltlske i politicke uvjete isto kao i lehnickoistrazno-geoloske znacajke istraznih prost ora. ovo se namece iz nepotpullosti postojecih zakon­ skih i dijelom financijskih propisa i tdkoca pracenja njihovih nado­ puna posljednjih godina, kako 10 vide zainteresirani cimbenici. hrvatski zakon a rudarstvu s pratecim aktirna obllhvaea suvisc razlicitc mineralnc sirovine, narocito u dijclu njihovog pridobivanja i trzista na koje se plasiraju. nuzn<t su pojasnjcnja dvosmislenosti oko garaneije proizvodnih prava kompaniji koja jc dosla do otkrica ula­ ganjcm rizicnih srcdstava, kao i otklanjanje anahonih obveza pro ­ izvodaea da sudjcluje u daljnjim istrazivanjima. s drugc strane, zahtjevi 0 izvjcstavnnjll ircbajll biti razumljiviji, ddaljniji i rigorozniji, narocilo u definiranjll prihoda i troskova. poje­ dini dosadasnji uvjeti zajednickih pothvata mozda su sllvisc "veliko­ dusni", zbog podmirivanja izdvajanja i poreza na proizvodnjll od strane nacionalne naftne kompallije, narocito ii prostorirna s utvrdenom proizvodnjom. zbog toga, a i zbog izbjegavanja pojedinih suvise slozcnih "production-sharing" tipova ugovora prcdlaze sc i detaljno obrazlaze "moderni sistcm izdvajanja poreza" za promatrani dio naftne industrije, pri cemu se postojeei sistem nadopunjava dodat­ nim porezom na izdasnije dobiti (apt). vladina se dobit automatski povecava ii slucajll znacajnijih dodatnih dobiti od proizvodnje. istovremeno, polja s manjom izdasnoscll placala bi umjerene poreze na ostvareni prihod. predlaze se i us])ostavljanje deviznog rezima izdvajanja, posebno podesenog za naftrhl industrijll. va~,na jc poli­ ticka odluka deriniranje i medunarodna promocija uloge nacionalne naftne kompanijc kao samostalnog i izravno pristupacnog partnera kako medunarodnih kompanija, tako i okupijalisla pojedinih inicijati ­ va domaceg privatnog sektora koji dobiva sve veeu va~.nos1. rjcsenjem ovoga sklopa prcdllvjcta otvorili bi mogucnost da hrval­ ska rcalizira agresivnu i cfikasnu kampanju naftne prornocije. cial note or thanks to mr boro vlasic and to mr slobo­ dan kolbah of ina, whom have liaised with me closely over the last year. t should perhaps declare at the oulset !hat i am not as knowledgeable about croatia's petroleum sector his­ tory, exploration potential and exist ing terms as i would like to be. given this, i have chosen to focus my initial remarks on the recent trends and practices which we, in commonwealth secretariat, marlborough house, pall mall, london sw i, united kingdom. 172 the commollwealth secretariat, perceive in the interna­ tional petroleum industry, particularly as they relate to the attraction of foreign private risk capital for the exploration and development of petroleum resources. then, having offered a snapshot of the international scene, i would like to share with you some specific thoughts about the most appropriate economic and fis­ cal terms and arrangements to apply to upstream petro­ le um operations in this key natural resource sector. in seeking to bring international arrangements to bear on our deliberations, lei me also highlight my par­ ticular vantage point. it is that or the commonwealth the free association oj" now 53 independent countries which in the earlier colonial era were tied with great britain. these commonwealth collntries arc spread arollnd the world in africa, europe, the caribbean, north and central america, asia, australasia and the pacific. collectively, these countries enjoy a varied and orten rich petroleum experience. thcy range from the major oil and gas producers like australia, canada, india, malaysia, nigeria and my own country, the uk, to small island states like grenada, malta, seychelles and tonga which, although at present lacking identified hydrocarbon resources, are seeking actively to attract a share or the explo ration capital of the international oil companies. in between these two extremes lie both the smaller producers (like cameroon, new zealand, papua new guinea and trinidad and tobago) as well as those countries (like ghana, mozambique, namibia and tan­ zania whieh are presently trying to commercialise their first hydrocarbon discoveries. this is the perspective from which my particular division in the london-based commonwealth secretariat extends confidential adviso­ ry services on petrolellm and mineral sector develop­ ment to commonwealth mcmber governments. 2. international trends i believe that most informed co mmentators would agree that in the last five years or so the international petroleum industry has been experiencing some signifi­ cantly changed investment conditions. many of these have resulted directly from changes in the policies and terms that governments are willing to offer the interna­ tional oil companies in order to attract their risk capital for exploration and development. and these modifica­ tions to petroleum sector policies and licensing terms thcmsclvcs spring from ccrtain rathcr morc fundamcn­ tal global forces in particular, during the last decade, the political changes in the former soviet union, east­ ern europe and elsewhere, and the very definite shift in emphasis g lobally in favour of the private sector as the prefcrred enginc for future economic growth and development. thcse changes have been sufficicntly far -reaching that, nowadays, virtually every government seeking to establish cffective policics and terms to attract forcign petrol cum exploration capital necds to lake cognisance of them. this, 1 would expect, inevitably also includes geologia croatica 49/2 croatia, notwithstanding your own oil and gas produc­ tion and reserves (which are, of coursc, relatively small by world standards). probably, the only governments which can afford to operate for a time in thc facc of these changed global conditions, if they so choose, arc those of the world's really major oil producing coun­ tries whose reserves and large national oil corpo ra­ tions give thcm a certain degree of independencc. let me now be more specific. the last few years have been characterised by a markedly more pro­ nounced competitive global environment for the explo­ ration and developmcnt risk capital of the international oil companies. many governments are competing for thcsc limited funds. compared with the 1980's, there is a far widcr choicc of explorat ion acreage worldwide for lhe oil companies to select, at a time when oil priccs (and hence company cash flows available to fund explo­ ration and development) doggedly remain at rclativcly unexciting levels. for a start , the countries of the fsu and of eastern europe are now welcoming forcign oil company investment to a much greater extent than ever before, although in several of those countries the applicable legislation and terms need clarifying and refining. several other examples ean also be quoted of countries offering important new exploration and devel­ opment opportunities to the international oil companies venezuela, vietnam and china being just some. secondly, some governments (like that or india) are inviting the oil industry to develop existi ng hydrocar­ bon discoveries, whilst others (for example, barbados, lndonesia and myanmar) arc offering thc companies access to on-going production through enhanced oil recovery arrangements. all other things bcing equal, and compared with explora tion in frontier areas, these are opportunities of special interest 10 the companies on account of lhe considerably reduced risks and morc ccr­ tain rewards. with the global acreage supply/demand balance seemingly shifting in favour of the com panics, it is little wonder therefore that in many countries these realities have already resulted in a more investor-friendly invest ­ ment regime. tn a classical economic response, the "price" of acreage has fallen and, in our common­ wcalth expcrience, this is reflected in morc flexible leg­ islative and contractual provisions, weaker minimum exploration work programmes, and softcr economic and fiscal terms. in cach of these responses, it is probably true to say that the special characteristics of petroleum operations arc also being more adequatcly reflected. one general instance is thc emergcnce in numerous countries in recent years of more attractive terms for frontier and/or deepwater operations. for example, angola, gabon, indonesia, ivory coast, malaysia, mal­ ta, nigeria, philippines, portugal and thailand arc some of the countries which have introduccd in recent years concessionary economic and fiscal terms to apply to operations in deep water or other frontier areas. i would like to cite a few more concrete examples to illustrate how some of the licensing tcrm s arc being nelli~l: current trend., and oplim:ll t;lx;uiol1 arr.mgcmcnts in the lntemalional pelmlt!um in(!u!)lry 173 cased . on the legislative side, some countries arc allow­ ing longer exploration periods for instance, in gabon, portugal and china, in angola ror deep water opcra­ tions, and perhaps also in norway (where there was a proposal last yea r for a morc certain ex tended explo­ ration period and for the production period to be ex tended to 50 years). some governments ror exam­ pic, namibia have also relaxed earlier limitations on the size and conriguration of exploration li ccnce areas. still others arc introducing specific re tention provi­ sions , a[lowin g companies to hold on to di scoveries wh ich are not immedia te ly thought to be economic this was onc o r the addit ional incentives on offcr to the oi l indus try in namibia 's secondliccnsing round and recentl y there we re similar proposa ls in bolivia and papua new guinca. as a last exampl e on the legal front, several governments arc relaxing their require­ ments for bank g uarantees to back up the minimum work programmes, at [cast in respec t o/" operations undertaken by the la rge r we[1 estab li shed oil compa­ nies; paki stan and again namibia are two examples that come to mind. from om commonwea lth s tandpoint, we are al so seei ng more exploration contracts awarded on the basis of a minimum work programme commitmcnt compris­ ing only scismic opcrations in the initial phase. certain­ [y, this is true of contracts covering fronti er exploration areas. in a very real sense, though, it seems that th e adven t of 3d seismic has helped to bridge the "accept­ ability gap" be tween seismic and wells as rar as many governments are concerned. where wells are offered by compani es as part of their minimum exploration pro­ grammc, these are orten cond ition al on the identifica­ tion of acceptabl e structures in the seism ic; some such arrangements do also co ntain back-out provisions invo lvi ng a specified payment to government in the event the company docs not actually e lec t to drill. there have also been one or two unwelcome instances where companies e ither stra ight-forwardly default on their earlier drilling commitments or otherwi se seek to renegotiate and dcfer those com mitments to a later peri ­ od. but it is probably in respect of the applicable eco­ nomic and fi scal terms that the more quant ifiable and obvious changes are tak ing place. many governments arc now offering acreage to !he oil industry under s ig­ nificant ly sorter economic and fi sca l terms than were availab[e only a few years ago . some of the changes arc dramati c, but in some extreme cases it is reasonable to question just how stable sllch generous concessions are likely to be in the longterm. unusua lly, for a country of s llch high petroleum prospectiv ity, the uk has the perhaps dub ious distinct ion of hav ing almost the most len ient petroleulll fi scal regime in the world; new dis­ coveries there will yield the brit ish government only a 33% share of profit s. needless to say, a few govcrn­ ments still demand and actua[ly still a ttrac t new investment under very tough economic tcrms; almost wi thout exception, thesc are the major petro lcum producers. in abu dhabi , ind ones ia, ma laysin, syria and venezuela, for example, the overall government take expresses as a percentage of total gross profits appar­ entry lies between about 85% and nearly 100%. the range of percentage govemment take around the world is still therefore very w idc, but there has been so me­ thing o f a downwa rds shift wi thin the range for those coun tries which have on ly fro ntier exploration acreage or less prospective areas 10 oller. it is interesting to note the main ways in which the reduction in government take is being brought about. in the last few years the world has, of course, witnessed a general reduction in corporate tax rates, as parl of the wider cconomic liberalisation measures adopted by many governments. income tax rates in the 30-45% range are now very common, compared with rat cs o f nearer 50% ten or so years ago. in most instances , the oil compan ies have benefited from these reductions. but many of the 1110re petroleum-specific econom ic provisions have also been cased . perhaps unsurprisi ng­ iy, the production royalty burden (frequent[y lev ied at a [2.5 % ra te a decade or more ago) has been dim inished, in several different ways. those few governments that nrc introducing a petroleum fiscal package con taining royalty and tax for the first time are setting the roya lty rate a t more modest levels for example, 9% in the ralk land islands. some governments are reducing their royalty rates. some countries (for example, g reece, greenland , madagascar and vcnezuela, to name but a rew) havc adopted a graduated s liding sca le royalty strueture so that lower rates arc paid on low production and higher rates on hi gh. in gabon, there is a royalty holiday period for marginal fields. in pakistan, royalty is c reditable against income tax payment s. and, or course, a few countries (such as the netherlands, nor­ way and the uk) have even abol ished royalties, e ither completely or for certain categories of product ion. production sharing te rms have also genera ll y cased in favour o f the companies. this includes both a rai si ng of the annual ceiling on the amount of production nvni l­ able [or cost recovery, as well as a reduced profit oil share for the slate. many examples cou ld be ci ted but in some cases (for examp le, malaysia and the philip­ pines) more fa vourable cost oil lim its a rc avail3ble for deep water operations. certain other aspec ts or an economi c and fiscal nature also deserve ment ion. except in the case o/" high­ ly prospec tive acreage, it is probably true to say that there is a rcduced emphasis on the lise of (and cert ainly the amounts collected through) signature, discovery and production bonuses. there is less front-end loading of" fi scal burdens and an increasing lendeney for the usc of progressive revenue-sharing mechanisms (an important trend to which r shall refe r again later). the re is per­ haps also a growing awareness o/" the desirability of treating foreign and domesti c investors equal ly, as well as public and private investors. and, something by way oj" a contrary impact , tax administrations arc paying more a llenlioll to trans rcr pric ing concerns and to 174 enforcing compliance and reporting requirements; in a similar vein, antiquated deductions such as depiction allowances arc being withdrawn and rules are being adopted to prevent thin capitalisation practices. these latter actions arc all designed to ensure a morc rational and fair tax base which, of course, partially offsets the reductions in tax rates. significantly \00, many 1110rc of the economic and fiscal terms contain biddable and negotiable e lements. scope may be g iven for this in govern ing legislation slich as the need to agree with investors the top two rates or additiona l profits tax in nami bia or morc orten, in the case of production sharing arrangements, some or all or a government's preferred parameter val­ ues are set out in its model petroleum agreement but the actual cost oil and profit oil percentages are negot i­ ated and agreed with investors on a case by case basis: indi a is one of many countries that follows this approach. orten, the same goes for participation levels and , occasionally too, royalty . the added degree of flexibi lity inherent in this negot iations approach is not at all surprising in the present oil industry investme nt climate. there is one final point i would like to make regard­ ing international trends and practices, and that concerns the apparently diminishing ro le of state participation. this is, of course, consis tent with the increased empha­ sis being placed more generally on the contribution to be made by the private sec tor. thus, we learn that bar­ bados, f inland , hungary and india arc among the nume rou s coun tries worldwide that are partially pri ­ vatisi ng their national oil companies. in many other countries, recent licensing rounds have proceeded on the basis of a reduced participation interest by the s tate for example, in colombia for small fields, in philip­ pines for deep walei' operations, in pakistan for less prospective acreage, and in gabon, greenland, nether­ lands and tanzania for all new licences. in still other countries the requirement for any level of state partici­ pation has apparently been removed completely for example, in new zealand, peru, seychelles and trinidad. and in the instance of those few countries such as the falklands and namibia which are perhaps fortunate enough to be commencing their petroleum sector arrangements from scratch, there is no mandato­ ry requirement for state participation. clearly then, the petroleum world is moving on. and governments which arc now seeking to increase the involvement of private and foreign oil companies in the furthcr development of their national petrolcum resources, including (as i understand it) croatia, will need to lake heed of thesc trends and developments in the international scene if they a rc to successfully achieve their objectives. gcologin croatica 49/2 3. desiraille characteristics of an economic and fiscal regime let me now turn to a more detailed consideration of the principal economic and fiscal terms appropriate to upstream petroleum operations. apart from the actual or perceived petrolcum prospectiv i ty of a country or area, the economic and taxation terms imposed by gov­ ernments are of paramount importance in determin ing the interest or otherwise of the multinational oil compa­ nies in seeking exploration ac reage. (an appropriate legislative and, usually, con tractual framework is also, of course, necessary). the economic and fi scal terms determine the balance between the inevitable risks and the hoped-for rewards associated with all petroleum operations; they may make or break a deal between an oil investor and a governmenl. it almost goes without saying that examples can be cited of both "good" and " bad" petroleum fiscal regimes, and i wou ld like now to outline what i believe are the desirable, if not essen­ tial, characteristics of an economic and fisca l package for upstream petroleum operations. a mode rn petrol eum economic and taxation pack­ age should be designed to achieve severa l e nds. obvi ­ ously, it must s imultaneously satisfy the critical requirements of governments as well as thosc of investors. in very broad terms, governments will wish to ensure that, whilst yielding them an acccptable level and pattern of tax and other receipts, preferably at no or minimal direct cost to the state, the package attracts an adequate level of investment on a recurring basis and sustains a reasonable level of petroleum sector activity. from the investors' standpoint, the fiscal regime shou ld allow the companies to fully recover their outlays, as quickly as possible, and allow them to retain an ade­ quate level of profits; the oil companies also strongl y prefer the taxation terms to be known in advance and to remain stable throughout the life of thei r petroleum operations. these seemingly eonjlicting objectives can in fact be reconcil ed successfu lly if the fiscal package is care­ fully constructed. what then should be the principles upon which such a package is formulated. i would suggest that the economic and fi scal regime should be straight-forward in design and transparent in application. (this cases understanding, negotiation and administration). whilst containing some in-built flexi­ bility, it should involve the exercise of minimal gov­ ernment discretion ex-post. it should be neutral in effect (creating no distortions) and encourage maximum effi­ ciency in operations. it should be predictable in its impact. it should yield government at all times during the production phase some minimum level of "take", but allow the companies to recover their costs quickly. the bulk of the government's take shou ld a rise through taxes and other revenuc-raising mechani sms based on profits, and probably also on profitability. in fact, in exchange for "front-end" relie f (g ranted, for c xamplc, by import duty concessions, modest royalty nellisl: currcm tre uds ;lild optimal tax;liion arr:lilgemcms in the imem;llion;ii pt:lroleurn i ndu~l ry 175 rates and accelerated depreciation for tax purposes), the tax pac kage can be struclured so as lo enable the gov­ ernment 's take to build lip fairly quickly afte r the point of cos t recovery and then ri se, in a progress ive manner, still further as the overall level or rate of project prof­ itabilit y inc reases . the possibilit y for tax leakages, e ith e r dom esti call y or internationally, should a lso be minimi sed ; in this regard, we can not e in pass ing that supposed concessions like tax holidays are ineffi c ient and probably ineffective. there arc numerous cxamples worldwide of specia l pc trol eum economic and fi scal packages which re jlec t most, if not ali, of these principles. such fi scal arrange­ ments arc balanced and fair to both companies and host governments, in both the short and the longtenn ; they the reby lay the economic fra mework for a stable work­ ing re lationship between the part ies tha t may endu re for several decades. 4. progressive revenue-sha ring mechanisms it is sometimes argued that progressivity is one of the key features of such fiscal regimes which make for grea te r stabil ity in the inves tor-governmen t re lation­ ship. ce rt ai nly , from our standpoint, progress ive rev­ enu e-s harin g mechani sms seem to be featurin g more o ft en in pe tro leum eco nomic and fiscal arrangement s. let me say a few more words on this particular topic. a pe troleum fi scal reg ime is said to be progress ive if it yie lds for government a higher percentage share of fieldlife pretax profits from any very profitable devel­ o pments than it docs from any developments of more modest profitabi lity. under such a scheme, the govern­ ment 's share will be low on any marginal developments thi s he lping to ensure the ir commercia lisation in the first place but will be increasingly greater the more attrac ti ve is the petroleum project. a high government share from any hi ghly profitable operations is the quid pro quo ror the more lenient tax treatment of develop­ ments o r more modest profitability. fn order to generate this progress ivc enccl overall , at least one of the spec i­ fi c re venuerai sing e lements in the fiscal regime must be linked to some measure of project projirabiliry, and not just thc quantum of profits. us ually, the profitabi ­ lity meas ure selec ted is e ither a rate of re turn or the investment multiple (sometimes also called the "r-fac­ to r"). in prac tice, the two most common revenue-shar­ ing mechanisms which have been adapted and adopted in thi s way a rc the additiona l profi ts tax (wh ich a lso goes by many other names, such as resource rent tax) and produc ti on sharing arrangements. occasionall y, though, royalti es, state participation and even , excep­ tiona]!y, income tax, have bcen made progress ive. many examples can be quoted of each. a survey i conducted in 1993 concluded that about one country in e ight had incorporated progressive revenue-shar ing mechani sms in their petroleum regim es. since then, even more co untries have adopted them. some of the leadi ng examples of the rate of re turn based additional profit s taxes are : aus tralia , namibi a and papu a new guinea; 1 understand that poland and kazakhstan have also recent ly adopted th is fo rm of lax. algeria , angola, ghana, india, malta, qatar and zambi a arc just some or the countries that have linked the ir producti on shares to a rate of return or r-factor. and to quot e just one other examp le, tunisia has a graduated sliding scal e of both royalty and income tax ratcs where the rcspcctive rates of levy are determined by the r-factor. 5. one possible optimal taxation package in turning to the concluding sec tion of my presenta­ tion , i would like to propose a possible optimal taxation package for the upstream pe trole um sec to r. there is noth ing te rr ibly revolutionary about it , and no doubt some people will maintai n that tax at ion can neve r be opt imal! but laxat ion is, and seemi ngly a lways has been, an inev itable pa rt of life . two thousa nd years ago, as told by saini luke in the bibl e: " ... ihere weill out a decree from caesar augustl/s, lhat aft fhe lvorld shollid be taxed ... .. . alld all well! to be taxed. every aile ii/to his owl/ city". the fisca l package which f am about to outli ne exhibits the desi rable characteri stics j referred to in sec­ tion 3. it can achieve the broad obj ectives, and satis fy the minimum requirements of governm ent s and investors, which i also brie n y alluded to. thi s fiscal regi me comprises an ad-va lorem royalty, a modern petroleum income tax and a multi -tie r add i­ tional profi ts tax. state pa rti c ipati o n ean also be accommodated , if necessary. t hese a re the principa l components . 1 wou ld a lso ex pect annual a rea rental charges to be levied. but duti es and sal es taxes on imported and exported items necessarily and exclusive­ ly required for the petroleum operations should be min­ imi sed and, at least d ur ing the ex plora ti on phase, preferably not be lev ied at al l. (thi s reduccs the front ­ end costs of the compani es an d helps to ensure tha t every $ they spend in the cou ntry is devoted 10 physical exploration work per sc). the right of a fore ign party to export it s petroleum produced , to have unfe ttered access to the foreign exchange proceeds generated, to be able to repatriate its profi ts freely, and for the petro­ leum produced to be va lued for royalty and tax purpo­ ses at fa ir intcrnational marke t prices, should all be part o f the overall econom ic and fiscal package too. le t met now ou tline in turn each to the princ ipal componenls of this package, beginn ing wi th royalty. royalt y should be imposed on an ad-valorem basis, and at a modest rate , on the value of o il and gas pro­ duced. it should be payab le all entities in the licence. this will yie ld at a ll times during thc produc ti on phase an appropriate minim um level of take for govern men t thcreby satisfying political as well as econom ic objec­ tives as the petroleu m (a key non -re newable natural resource) is exhausted. however, to prov ide for even 176 greate r fl ex ibility, the minister should be author ised to wai ve, de fc r or reduce the payme nt of royalty in c ir­ culll s tances whe n to clo so is like ly to maximi se the recovery or hydrocarbo ns from a particular fi e ld in a g iven time pe riod , for example, on marginal opera tions durin g fi e ld produc ti on dec line . if ihe gove rnme nt wi shes to gain access to oil gas resources direc tl y, there could al so be a provi s ion requiring the royal ty \0 be paiel in kind. the second c lement in the fi scal package is a spe­ c iall y rormulat ed petroleum income tax (p it), with de tailed provisions tailored to suit the unique character­ istics o r the oil and gas industry. the pit rate should be es tabli shed some whe re in the 30% to 40% range (de pend ing at what rates the other clements in the pack­ age arc sct at ) and lev icd in a non-discrimi natory man­ ncr. in o rde r to accele rate cost recove ry by the inves t­ ing oi l compa ni es, qual ify ing project expenditures should be depreciated over a shon time pe riod: immedi­ ate w rite-o lt in fu ll would be appropriate for ex plo­ rati on (and , of course, operating) expenditures, whi ls t development expenditures could be allowed ove r a 3, 4 or pe rhaps 5 year period. in the computation of pit, royalt y would be an allowable deduction and losses should be pe rmitt ed to be carried forward without res tri c ti on. pit should be assessed on a company by company basis, meaning that would be no narrow ring­ fe nc ing thus providing some additional incentive for furthe r ex pl oration and development within the country. ord inaril y, it cou ld be expected that the bulk o r a gov­ e rnment's take from pe troleum operations would arise thro ugh th is pit. ghana, namibia, papua new guinea and seyche lles arc examples of some o f the coun tries wh ich have adopted mode rn pit rules along the lines sugges ted he re. a lllulti -ti c r add itional profits tax (apt) would constitute the third (and often last ) princ ipal clement in the ri scal package. royalty and pit would be allowabl e deduc tions in the computation of this cash-now based tax , whi ch would only be paid in the event or, and in respect or, more profitable operations. probably trig­ gered by an after-tax rate of return (which cou ld a lso be inrlati o nindexcd , to give the investor added prot cc ­ ti on) , a multi -ti er apt structurc wou ld injec t an eve n great e r deg ree of prog ressivity into the overa ll fi seal package than a s ing letier apt. (tn practice, two o r three tie rs should be sufficient). as with the thresholds tilat trigger it, some or all of the apt tax rates could be negotiable on a case by case basis with each investor, the re by effec tive ly de termining the max imum marginal rate o f to ta l government take on the basis of the per­ ce ived charac te ri s tics or each licence area. tt mi ght be appropri<lt e to ring-fence the apt more narrowly than the p it in orde r to lend balance to the ti ming and pro­ ri le of the gove rnment's take. an option could al so be included ror the government to take the apt in kind, if access to physical quan tities of oil and gas is des ired. if necessary , it wou ld also be possibl e for some form of s lat e participation to be included withi n this geolog ia croalic;l 49n fi scal package. obviously, though, the royalty, pit and apt rates wou ld have to be established and/o r negotiat ­ ed bearing in mind the nature and extent of the partic i­ pation component. the outlined fiscal packa ge is a workable " main ­ s tream " one, in the sense that by and la rge somc thing similar to it is adopted by about half of the collntries in the world today. to a greate r or lessc r ext cnt, it is embraced by both small and large countries; by c urrent produce rs, presently non -producers and for frontier acreage; and by both developed and less-developed countries. this package is mocie rn , strai ght -forward in des ign and relatively easy to administe r. it is llexibl e in impact, au tomatically adjusting the ac tual fi scal burden to the intrinsic profitability of the part ic ular pe troleum ope rations. companies can recover the ir costs qu ickl y and onl y the n wi ll the gove rnm e nt 's take bui ld up. assuming appropr iat e rates for the roya lt y, pit and apt, it is inte rna ti on a ll y co mpe titi ve and the pit should be a creditable tax fo r fore ign o il compan ies in the ir home jurisdictions. it pu ts all parti c ipant s in the venture on an equal footing and is equally applicabl e to oil and gas. it can be so s truc tured that othe r important national object ives can be sati s ri cd simultaneously if desired such as direct access to oil and g[ls production, anci a ro le for state participation. i have deliberatcly shyed-away from ac tually rec­ omme nding that this particular ri scal package should bc adopted by croatia, although 1 be lieve it would in fac t be qui te appropriate he re, too. in prac tice , each cco­ nomic and fi scal regime must be tailored to address and re fl ect the part ic ular c ircumstances of each country. in this regard , i am aware that, at leas t in the recent pas t, croa ti a has expressed a pre fe re nce for cost-recove ry production sharing arrangements. my unde rstanciing is tha t, unde r these arrangeme nts, lna-na rtap lin assumes a 50% state interes t a ve ry large int e res t from the deve lopment stage (perhaps uncl e i' carri ed int eres t te rms) and that the foreign part ies' tax li a bility is sati s­ fied out of the state's share of profit oil. the /orl7l of croat ian take is the refore qui le diffe rent 10 that which wou ld accrue to a governme n t und e r the roya lty and tax -bascd fiscal package i have just outlined; al so , except with respcct to the phys ical produc tion rates, the ove ra ll economic impac t or the present c roatian te rms cannot be progress ive. presumably, there a re speci fi c reasons why c roatia has dec ided to pursue wha t, in our vie w in the com­ monwealth secretariat, arc the more complicat ed pro­ duction sharing arrangeme nts . howeve r, even within a production sharing format , ma ny of the desirable char­ acteristics of a fisca l package which i describcd earl ier can be accom modated , and croatian auth oriti es may pe rhaps wish to rcvisit th ese . as one final point of information on th is matter, 1 would s imply li ke to br ing to the atten tion one of the main conc lusions of the lon­ don -based pe troconsultant s ' 1996 annual review of 110 pe troleum fi sca l regimes, name ly, th e apparel1l trend during the last two years away from produc tion nellist: curre nt tn;lld~ ,md opt ima l tax ation armngell l ell1~ illlhc internati onal i\;trolcum industry 177 sharing contracts towards a royalty/tax structure. to quote from the executive summary of petroconsul ­ tants' recenlly publi shed review: "the cflallge ill p,ollll7llin to a royalty/tax syste lll reflects aile of tfle iiinill trellas ill fiscal regil1les ai/ring the last two years /lotahly ill lat/ii alllerica alld east­ em europe fhis type of fiscal regillle. prorillctioil sllnr­ illg coli till lies to nominate ill tfle nliddle enst, cis alld far eas/: alu/ough ill vietnaljl, for exalllple, tlle pscs nre beills illoriifieri so till/i ihelj a/so illclllrie roljaltlj allri tax elelllellts." 6. concluding remarks in bringing this present ation to a close, r must acknowledge that 1 have necessarily been rather selec­ tive. t have concentrated on the principal economic and fiscal terms which have a direct bearing on the divis ion of upstream petroleum project profits between a host government and a private sector investor. of course, traditionally, petroleum arrangements wit h foreign investors also embrace several other telms with an eeonomic impact such as licence area rentals, minimum annua l training expenditure commitments and mini ­ mum exploration expenditure commitments. there are also important provisions with respect to forei gn exchange entitlements, val uation of petroleum, account­ ing rules, bank and performance guarantees etc. 1 have ignored all or these other mallers, either because they are of a secondary monetary magnitude or because they arc of a dittercnt nature in the overall schcme or things. equall y, t have not sought to comment on the potential­ ly significant indirect economic benefits which petrole­ um operations can generate such as employment cre­ at ion, the impetus for regional development, encourage­ ment for the further development of related service industries etc. 1 hope my remarks have been of interest. attracting private (and especially fore ign) exploration capital to a particular host country is a time-consuming, challeng­ ing and orten complex exercise, requiring a multi-disci­ plinary approach in which the geological, economic and legal considerations arc successfully blended. i wish croatia well in your future petrol eum exp loration , development and production endeavours. geologia croatiea 49/2 moro & cosovic.indd 1. introduction rudists are important macrofossils in the upper cretaceous of the adriatic carbonate platform. among them, hippuritids are common, particularly in the santonian of southern istria (moro, 1997; moro & ćosović, 2000) where they have been used for detailed biostratigraphy (polšak, 1965; polšak et al., 1982). polšak (1965, 1967) recognised seventeen species (table 1) based on morphological characteristics (s and e pillars, shell thickness, visceral cavity and ornamentation). determination of the species within the family today is based on a combination of morphological elements (ligamental ridge, teeth, and pillars). the sector l–p1–p2, i.e. ligamental ridge and pillars of the lower valve (dechaseaux & coogan, 1969) are also very important for identification. a proposal for taxonomic re-evaluation of vaccinites species from the santonian limestones of southern istria (croatia) alan moro and vlasta ćosović the base for taxonomic re-evaluation is skelton’s (1976) description (fig. 1) of hippurites and vaccinites, involving evolutionary rotation of the myocardinal axis (skelton, pers. comm. 1973; in skelton, 1976), which was further developed by simonpiétri & philip (2000). the difference in angle, as a consequence of ventral expansion, produced a larger body cavity in vaccinites in comparison with hippurites. vaccinites shows different values of the angle between the teeth and the ligamental ridge, as well as that between the ligamental ridge and the p1 pillar. such angles have been based on different criteria for the description and determination of the hippuritids from the southern pyrenees (vicens, 1992), ostuni area (italy – laviano & maresca, 1992) and boeotia (greece – steuber, 1999). according to vicens (1992), angles between the teeth and the ligamental ridge may be useful for determining the genus and occasionally the group to which a species belongs. also, beside other angles, the angle between the ligamental ridge and the p1 pillar (lp2 in vicens, 1992) could be useful for determining the species groups. we have chosen the aforementioned two angles (fig. 1) because they are the most prominent characteristic of the studied individuals, which flourished during a short time span, and in addition they have been found within the same facies (polšak, 1965, 1967), as scattered individuals together with radiolitids in mud supported early santonian floatstones (moro, 1997; moro & ćosović, 2000). given the morphological variability of analogous living bivalves (e.g. oysters), among which more than a few species rarely co-occur in the same facies, the apparent high diversity of species recognised by polšak (1967) may be questioned. our re-evaluation of vaccinites species is based on biostatistics and on the field and laboratory experiences of the senior author. we are aware that statistical analysis is not a magic tool that will resolve the taxonomy of rudists. when specimens are incorporated in carbonates and it is quite difficult to extract them for determination, their identification at the species–group level using the simplest methods and tools in the field, has to be considered. geologia croatica 57/2 139–147 6 figs. 2 tabs. zagreb 2004 key words: vaccinites, taxonomy, cluster analysis, santonian, adriatic carbonate platform, istria, croatia. department of geology and paleontology, faculty of science, university of zagreb, zvonimirova 8, hr-10000 zagreb, croatia; e-mail: alan.moro@public.srce.hr abstract rudists, especially members of the family hippuritidae, were common dwellers on the adriatic carbonate platform during the late cretaceous. morphological elements (ligamental ridge, teeth, pillars, length of the contour around the inner margin of the outer shell layer and the ratio between this length and the distance between the sutures of the pillars) from the transverse shell sections permit different species to be defined within the family. transverse sections of vaccinites specimens from the santonian limestones in southern istria show different values of the angle between the teeth and the ligament ridge, between the ligamental ridge and the e pillar (p2), and of the ratio between the length of the contour and the pillar suture distance. cluster analyses (ward’s and unweighted pair–group average methods) using measured elements, allowed the definition of three species groups from seventeen species at the beginning of study. 140 geologia croatica 57/2 141moro & ćosović: a proposal for taxonomic re-evaluation of vaccinites species... the measured structural elements are obtained from polšak’s (1965, 1967) transverse sections of the right valve of vaccinites species (fig. 1). they include the following: – angle between the ligamental ridge and the e-pillar (l/p2 in the further text, a in fig. 1); – angle between the ligamental ridge and the teeth (l/t in the further text, b in fig. 1); – inner diameter (rv interior, after laviano & maresca,1992); – length of the contour around the inner margin of the outer shell layer (u in the further text; steuber, 1999); 2. material and methodology all specimens have preserved ligamental ridges, as well as pillars. teeth elements are in some specimens indeterminable probably due to calcite infilling of the shell interior, which has the same colour as the rest of the shell. shell layers are poorly preserved. all specimens have been transversely sectioned. here, we deal with broken specimens; all of them cylindrical in shape with the same diameters along the preserved part of specimens (see polšak, 1967 – pl. 73, fig. 2; pl. 75, fig. 2; pl. 76, figs. 1 and 4; pl. 78, fig. 1; pl. 85, fig. 2). the constant diameters of the vaccinites specimens allowed us to conclude that all specimens considered for this study were adults. a b fig. 1 upper part of figure: transverse section of hippurites (a) and vaccinites (b) attached valves with rotation of myocardinal axis (from skelton, 1976). lower part of figure: transverse section of vaccinites boehmi (douvillé), v. atheniensis (ktenas) and v. oppeli santoniensis (kühn) from polšak (1967) with l–p2 (a) and l–t (b) angles. transverse sections not to scale. 140 geologia croatica 57/2 141moro & ćosović: a proposal for taxonomic re-evaluation of vaccinites species... – the ratio between the length of u and the distance between the sutures for p0–p2 (u/p0–p2 in the further text; steuber, 1999). the angle l/p2 is formed by straight lines which follow the general extension line of the ligamental ridge, i.e. which passes through the end of the ligament and the point where it intersects the inner diameter of the shell, and that which passes through the end of the pillar and the point where the p2 pillar intersects the inner diameter of the shell (fig. 1). for measurement of the ligament–teeth (l/t) angle, the straight lines that follow the general extension of the ligamental ridge (as for l/p2 angles), and that which passes through the centre of both teeth, was considered (fig. 1). the measurements are displayed in table 1. statistical analyses (35 specimens for l/p2 and l/t and 17 for u and u/p0–p2) were calculated using the past software program (hammer et al., 2003). to avoid any possible dependency between variables, and to achieve the line of best fit, we plotted reduced major axis (rma) (fig. 2). unlike standard approaches, this model is invariant to the selection of which variable is portrayed on which axis, and to differences in variable type (macleod, 2004). the data were also subjected to cluster analysis. cluster analysis is one of the most widely used and commonly understood multivariate analytical techniques in the palaeontological literature. it segregates entities (species, specimens, measurements) into “naturally occurring groups” and quantifies the between-group relationships (parker & arnold, 1999). hierarchical cluster analyses were calculated using the ward method with euclidean distance and unweighted pair– group average method with euclidean distance. ward’s and unweighted pair–group methods join two entities with the highest mutual similarity at each iteration. at each step, a potential new cluster that yields the lowest total euclidean distance is formed. this continues until a single cluster remains. recognition of “significant” clusters within a dendrogram are based on fig. 2 reduced major axis showing the relationship between l/p2 versus l/t angles in vaccinites species from southern istria (after polšak, 1965, 1967). the size of the transverse sections of the right valves of vaccinites species are reduced with respect to their original size. numbers attached to the transverse sections correspond to numbers given to species in table 1. dotted line encircles statistically determined groups. 142 geologia croatica 57/2 143moro & ćosović: a proposal for taxonomic re-evaluation of vaccinites species... the shortest distance between paired vaccinites specimens. 3. biostatistical results hierarchical cluster analysis (ward’s method in fig. 3) on the ligament–e pillar (l/p2), ligament–teeth (l/t), inner diameters, lengths of the contour (u) and the ratio between u and suture distance p0–p2, produced three main cluster groups. the species v. atheniensis (1) (known as adult growth stage of v. chaperi; steuber, 1999), v. cornuvaccinum (2), v. taburni (3), v. cf. gosaviensis (9) and v. kuehni (10) represent the first cluster. the cluster combines species with l/p2 angles from 2–27º, l/t up to 20º, u between 24.2 and 84.6 cm, and u/p0–p2 varying from 6.0 to 10 cm. the second cluster (fig. 3) contains five species, v. inaequicostatus (8), v. cf. kuehni (11), v. oppeli santoniensis (12), v. sulcatus (13) and v. gosaviensis (17). the species gathered together are defined by the following characteristics: l/p2 varying from 43 to 77º, l/t from 15 to 30º, u between 20.1–46.5 cm, and u/p0–p2 between 5.1 and 7.1 cm. the third cluster (fig. 3) is composed of the following species v. giganteus (4), v. giganteus medulinus (5), v. salopeki (6), v. vredenburgi (7), v. boehmi (14), v. extremus (15) and v. anici (16). the cluster includes species with the l/p2 angles between 19–55º, l/t values between 42 and 74º, the u between 31–42.4 cm, and the u/p0–p2 ranging from 6.3 to 10.6 cm. the applied unweighted pair–group method (fig. 4) reveals the identical grouping of species. the results emerging from the cluster analysis of the measured angles (l/p2 and l/t angles, fig. 5), identify three cluster groups: the first cluster (v. giganteus (4), v. giganteus medulinus (5), v. salopeki (6), v. vredenburgi (7), v. boehmi (14), v. extremus (15) and v. anici (16)), with an average l/p2 value of 39.57º and an average value of l/t of 52.14º. the second cluster (v. atheniensis (1), v. cornuvaccinum (2), v. taburni (3), v. cf. gosaviensis (9) and v. kuehni (10)), combines species with the lowermost values of the angles, the average l/p2 value of 12º and of l/t of 5.4º. the third cluster, (v. inaequicostatus (8), v. cf. kuehni (11), v. oppeli santoniensis (12), v. sulcatus (13) and v. gosaviensis (17)), is characterized by the largest disproportion of measured angles, the average value of l/p2 around 59º and of l/t around 13º. the unweighted paired–group method of measured angles (fig. 6) has resulted in the same grouping of species. a particular difference in grouping of the seventeen species between linear graph (fig. 2) and multivariate statistic analysis (figs. 3–6) exists. the species with indefinite values of l/t or l/p2 angles (for statistics we put value 0) are involved in this discrepancy. 4. morphological observations the determined groups of vaccinites show certain degrees of morphological similarities. group i (fig. 2, table 2) contains forms with an elongated ligamental ridge, which are truncated at the tip. p1 is pinched with an oval head. p2 is pinched at its base and is longer than p1. p1 and p2 could be located no. of l/p2 l/t l/p2 l/t d π u u/p0–p2 specs. min/max min/max (°) (°) (cm) (cm2) (cm) (cm) 1 v. atheniensis 3 18/22 6/8 20 7 4.1 52.8 84.6 6.0 2 v. cornuvaccinum 1 11 2.7 22.9 24.2 8.96 3 v. taburni 3 19/21 20 3.2 32.2 29.0 10 4 v. giganteus 2 37/37 41/47 37 44 3.1 30.2 36.1 8.804 5 v. giganteus medulinus 1 19 42 3.0 28.3 42.427 10.606 6 v. salopeki 5 30/40 42/48 35 45 2.7 22.9 32.2 7.318 7 v. vredenburgi 5 47/53 53/61 50 57 2.6 21.2 31.0 7.75 8 v. inaequicostatus 2 34/61 22/22 48 22 4.5 63.6 36.9 7.096 9 v. cf. gosaviensis 1 27 4.8 72.3 32.2 6.851 10 v. kuehni 1 2 4.3 58.0 43.75 8.75 11 v. cf. kuehni 1 62 2.8 24.6 27.0 6.923 12 v. oppeli santoniensis 2 77/77 15/15 77 15 4.5 63.6 46.5 5.81 13 v. sulcatus 1 43 2.3 16.6 20.1 6.931 14 v. boehmi 2 40/57 46/46 48 46 2.7 22.9 31.0 6.326 15 v. extremus 1 33 57 3.7 42.9 37.9 6.851 16 v. anici 1 55 74 2.9 26.4 33.5 6.836 17 v. gosaviensis 3 52/70 30/30 64 30 2.7 22.9 26.0 5.098 table 1 the list of vaccinites species from the santonian limestones with measured parameters. 142 geologia croatica 57/2 143moro & ćosović: a proposal for taxonomic re-evaluation of vaccinites species... no. of polšak’s (1967) species s im il a ri ty fig. 3 hierarchical cluster analysis (ward’s method) including all parameters for vaccinites species from santonian of southern istria. numbers i, ii and iii correspond to statistically determined groups. group i group ii group iii l/p2 (º) 19–55 2–27 43–77 mean l/p2 (º) 39.57 12 58.8 l/t (º) 42–74 7–20 15–30 mean l/t (º) 52.14 3.85 13.4 u 31–42.4 24.2–84.6 20.1–46.5 u/p0–p2 6.3–10.6 6.0–10 5.098–7.096 mean u 34.9 42.75 31.3 mean u/p0–p2 7.78 8.112 6.37 v. giganteus v. cornuvaccinum v. inaequicostatus v. gig. medulinus v. taburni v. o. santoniensis v. salopeki v. cf. gosaviensis v. cf. kuehni v. vredenburgi v. kuehni v. sulcatus v. extremus v. atheniensis v. gosaviensis v.boehmi v. anici total no. of sp. 7 5 5 table 2 main characteristics of species groups recognized through statistical analyses. 144 geologia croatica 57/2 145moro & ćosović: a proposal for taxonomic re-evaluation of vaccinites species... close to each other. the teeth and their array are curved towards the anterior. a distinction between species included in this group, v. vredenburgi and v. giganteus, has been problematical for a while (laviano & guarnieri, 1989; steuber, 1999). the group ii (fig. 2, table 2) contain one of the oldest known hippuritid species, vaccinites cornuvaccinum which is also the type species of the genus vaccinites (bronn, 1831; fischer, 1887; dechaseaux & coogan, 1969; steuber, 1999). separating species, which are members of this group, v. cornuivaccinum from v. taburni has frequently been a problem, as well as another member of this group, v. atheniensis, which probably represents an adult growth stage of v. chaperi (steuber, 1999). also, v. cornuvaccinum and v. chaperi are considered to be of the same stratigraphic age, as well as coenozone, on the adriatic carbonate platform (slišković, 1968; polšak et al., 1982; steuber, 1999). the ligamental ridge is slightly curved toward the anterior, especially at the end. p1 varies from parallel sided to considerably pinched at its base with an oval head. p2 is pedunculated with an oval head which can be slightly curved in an anterior direction. p1 and p2 can be fused at their junction with the inner diameter of the shell. the teeth are almost in line with the ligament ridge. specimens of the group iii (fig. 2, table 2) are characterised by a straight ligamental ridge, slightly curved towards the anterior. p1 has a round or oval head more or less pinched at its base and generally shorter than p2. p2 is straight, and pinched at the base with an elliptical head. teeth are both beside and in prolongation of the ligamental ridge. fig. 4 hierarchical cluster analysis (pair–group method) including all parameters for vaccinites species from santonian of southern istria. numbers i, ii and iii correspond to statistically determined groups. no. of polšak’s (1967) species s im il a ri ty 144 geologia croatica 57/2 145moro & ćosović: a proposal for taxonomic re-evaluation of vaccinites species... 5. conclusion the aim of this work has been to check the possibility of taxonomic re-evaluation of vaccinites species using cluster analysis (ward’s and unweighted pair-group average methods). cluster analyses of the measured elements indicates a relationship between the position of the teeth, ligamental ridge, e pillar, the length of u contour and the p0–p2 suture distance in the santonian vaccinites species from southern istria. the cluster analysis, based upon field and laboratory observations, results in the recognition of three groups. the first group, v. giganteus, v. giganteus medulinus, v. salopeki, v. vredenburgi, v. boehmi, v. extremus and v. anici, shows angle values between 19 and 55º (l/ p2), 42–74º (l/t), u values from 31–42.4 cm and u/p0–p2 from 6.3–10.6 cm. the dental array is curved in an anterior direction. the second group includes the species vaccinites cornuvaccinum, v. chaperi (=v. atheniensis), v. taburni, v. cf. gosaviensis and v. kuehni. the characteristics of this group are: l/p2 values 2–27º, l/t values 7–20º, u values 24.2–84.6 cm and u/p0–p2 values 6.0–10 cm. the teeth are almost in the line with the ligament ridge. the third group, v. inaequicostatus, v. cf. kuehni, v. oppeli santoniensis, v. sulcatus and v. gosaviensis, has angle values from 43 to 77º for l/p2, 30º or less for l/t (between 15 and 30º), u values from 20.1– 46.5 cm, and u/p0–p2 from 5.1–7.1 cm. the teeth are beside and in prolongation of the ligamental ridge. acknowledgements we wish to thank professors jean philip and peter w. skelton, as well as dr. ricardo cestari for reviewing the paper and giving valuable advice which fig. 5 hierarchical cluster analysis (ward’s method) taking into account l/p2 and l/t measurements for vaccinites species (polšak, 1965, 1967). numbers i, ii and iii correspond to statistically determined groups. no. of polšak’s (1967) species s im il a ri ty 146 geologia croatica 57/2 147moro & ćosović: a proposal for taxonomic re-evaluation of vaccinites species... fig. 6 hierarchical cluster analysis (pair–group method) considering l/p2 and l/t measurements for vaccinites species (polšak, 1965, 1967). numbers i, ii and iii correspond to statistically determined groups. improved the manuscript, and especially p.w. skelton for language improvement. we also thank r. košćal for computer preparation of figures. this work has been supported by a grant from the ministry of science, education and sport of the republic of croatia, projects 0119402 and 119315. 6. references bronn, h.g. (1831): hippurites.– in: ersch, j.s. & gruber, j.g. (eds.): allgemeine encyclopaedie der wissenschaften und künste. brockhaus, leipzig, 371–376. dechaseaux, c. & coogan, a.h. (1969): family hippuritidae gray, 1848.– in: moore, r.c. (ed.): treatise on invertebrate paleontology. the geological society of america, university of kansas, lawrence, n799–n803. fischer, p. (1887): manuel de conchyliologie et de paléontologie conchyliologique ou historie naturelle des mollusques vivants et fossiles [guide for conchyology and conchyological palaeontology of recent and fossil molluscs of the natural history – in french].– f. savy, paris, 1369 p. hammer, o., harper, d.a.t. & ryan, p.d. (2003): past–paleontological statistics, ver. 1.15.– http:// folk.uio.no/ohammer/past. laviano, a. & guarnieri, g. (1989): vaccinites vredenburgi kühn, 1932, from the upper cretaceous of apulia (southern italy).– boll. soc. paleont. ital., 28, 78–86. laviano, a. & maresca, m.g. (1992): paleontological characters of the species vaccinites vesiculosus (woodward).– geol. romana, 28, 49–59. macleod, n. (2004): prospectus and regression 1.– palaeontological newsletter. http://www.palass.org. no. of polšak’s (1967) species s im il a ri ty 146 geologia croatica 57/2 147moro & ćosović: a proposal for taxonomic re-evaluation of vaccinites species... moro, a. (1997): stratigraphy, paleoecology and vertical succession of rudist biostromes in the upper cretaceous (turonian–santonian) limestones of southern istria, croatia.– palaeo. palaeo. palaeo., 131, 113–131. moro, a. & ćosović, v. (2000): the rudist assemblages of southern istria – an example of environmentally induced succession within santonian limestones.– riv. ital. paleont. strat., 106, 59–72. parker, c.w. & arnold, a.j. (1999): quantitative methods of data analysis in foraminiferal ecology.– in: sen gupta, b.k. (ed.): modern foraminifera. kluwer academic publishers, dorderecht, 71–89. polšak, a. (1965): geologija južne istre s osobitim obzirom na biostratigrafiju krednih naslaga (géologie de l’istrie méridionale spécialement par rapport a la biostratigraphie des couches crétacées) [the geology of southern istria with special consideration of biostratigraphy of cretaceous deposits – in croatian with french abstract].– geol. vjesnik, 18, 415–509. polšak a. (1967): kredna makrofauna južne istre (macrofaune crétacée de l’istrie méridionale, yugoslavie) [the creaceous macrofauna of southern istria – in croatian and french] – palaeontologia jugoslavica, 8, 1–219. polšak, a., bauer v. & slišković t. (1982): stratigraphie du crétacé supérieur de la plate-forme carbonatée dans les dinarides externes [upper cretaceous stratigraphy of the carbonate platform of the outer dinarides – in french].– cret. res., 3, 125–133. simonpiétri, g. & philip, j. (2000): relations ontogenése-philogenése chez les rudistes: l’exemple des hippuritidae gray, 1848 [ontogeny–phylogeny relationships in rudists: the example of hippuritidae gray, 1848 – in french].– sciences de la terre et planétes, 330, 717–724. skelton, p.w. (1976): functional morphology of the hippuritidae.– lethaia, 9, 83–100. slišković, t. (1968): biostratigrafija gornje krede južne hercegovine [biostratigraphy of the upper cretaceous in southern herzegovina – in croatian].– bulletin du musée de la république socialiste de bosnie–herzégovine á sarajevo, sciences naturelles, nouvelle série, 7, 5–66. steuber, t. (1999): cretaceous rudists of boeotia, central greece.– spec. papers in paleontology, 61, 229 p. vicens, e. (1992): intraspecific variability in hippuritidae in the southern pyrenees, spain: taxonomic implications.– geol. romana, 28, 119–161. manuscript received march 12, 2003. revised manuscript accepted november 08, 2004. 148 geologia croatica 57/2 1. introduction crystals of the same mineral species can appear in different forms, i.e. habit types. besides numerous researchers, kostov (1966, 1969, 1970, 1975) has investigated the changes of mineral habit during the crystallization of a particular mineral species. he pointed to the influence of crystalline structure (unit cell dimensions, nature of bonds in the structure) and external conditions during growth (chemical composition of solution, supersaturation degree of solution, type of ingredients) on the change of crystal habit of the same mineral species. bravais (1851) observed the evident dependence between reticular density and probability of appearance of a particular crystal form. priority in crystal growth has the crystal form with maximal reticular density (bravais, 1851). in consideration of this fact, it is possible to determine the development sequence of barite crystal types by introduction of the term “average structural density of crystal” (krivovi»ev, 1971) which defines the total contribution of reticular density of all crystal form faces, and by calculation of the values of average structural densities for different habit types of barite crystals. barite is one of the mineral species, which could have extremely different habit types. braun (1932) the average structural density of barite crystals of different habit types biserka radanovi∆-guævica has determined seven different habit types of barite crystals on the basis of detailed investigation of relationships between morphological characteristics and mineral association. some specimens of barite from westmorland and county durham in the north of england, show up to six changes of habit during growth, from the crystals elongated in the [1 0 0] direction, through the crystals tabular on the basal pinacoid {0 0 1}, to crystals elongated in the [0 1 0] direction (seager & davidson, 1952). a similar sequence is described for barite crystals from the tjuja-mujun mine (solodovnikova, 1927). krivovi»ev (1971) separated three generations of different habit types of barite crystals from the beloreëensko locality, and determined the development sequence from the prismatic crystals elongated in the [010] direction, through the thick-tabular crystals elongated in the [0 1 0] direction, to crystals tabular on the basal pinacoid. this sequence is in accordance with decreasing average structural density of the crystals (krivovi»ev, 1971). an inverse development sequence was determined on barite crystals from krapinske toplice (zebec, 1976). a sequence from crystals tabular on the basal pinacoid, through crystals elongated in the [100] direction, to crystals elongated in the [0 1 0] direction, was accompanied with a change of genesis temperature and decrease of srso4 c o n t e n t (zebec, 1976). observations of phantoms and inclusions in crystals of barite from muddy creek, colorado, suggest at least five episodes of crystal growth, with g eol. croat. 52/1 59 65 1 fig. 4 tabs. zagreb 1999 key words: barite, habit types, reticular density, average structural density of crystal. kljuëne rijeëi: barit, tipovi habitusa, retikularna gustoêa, srednja strukturna gustoêa kristala. department of mineralogy and petrography, croatian natural history museum, demetrova 1, hr-10000 zagreb, croatia. abstract eight different habit types of barite crystals which could be classified into 4 essentially different groups were determined by morphological analysis: eb group barite crystals elongated in the [0 1 0] direction; ea group barite crystals elongated in the [1 0 0] d i r e c t i o n ; tc group barite crystals tabular on the basal pinacoid {0 0 1}; ec group barite crystals elongated in the [001] direction. by determination and comparison of the average structural densi ties of different habit types of barite crystals, it was possible to establish the spans of their values from 276.1 to 495.8, and overlapping of values for eb group with ea group and tc group with ec group. the sequence of habit types, with regard to the decreasing average structural density, i.e. the priority sequence of developing of barite crystal types, was determined: eb group ea group tc group ec group. saæetak morfoloπkom analizom odreeno je 8 razliëitih tipova habitusa baritnih kristala koji se mogu svrstati u 4 bitno razliëite skupine: eb skupina kristali barita izduljeni smjerom [0 1 0]; ea skupina kristali barita izduljeni smjerom [100]; tc skupina kristali barita ploëasti po baznom pinakoidu {0 0 1}; ec skupina kristali barita izduljeni smjerom [001]. odreivanjem i usporedbom srednjih srtukturnih gustoêa razliëitih tipova habitusa baritnih kristala utvreni su rasponi njihovih vrijednosti od 276.1 do 495.8, te su uoëena preklapanja vrijednosti za eb i ea skupine, kao i za tc i ec skupine. utvren je redosljed tipova habitusa s obzirom na smanjenje srednje strukturne gustoêe kristala, tj. prioritetni slijed razvoja baritnih kristala: eb skupina ea skupina tc skupina ec skupina. 60 geologia croatica 52/1 changes in morphology with respect to time (truebe, 1981). recently, researchers attempted to determine the dependence of barite morphology on different controlled conditions during experimental crystal growth (fernandez-diaz et al., 1990; prieto et al., 1992). numerous barite specimens with different crystal habits are stored at the collection of department of mineralogy and petrography of the croatian natural history museum in zagreb. systematic researchs of barite morphology and the reticular density of the crystal form faces was undertaken in order to try to define the priority sequence of developing of barite crystals types, on the base of calculated values of average structural density of crystal. this paper is the result of investigations performed as part of a master’s thesis (radanovi∆-guævica, 1995). 2. material and methods the crystals of barite from the mrzle vodice locality in gorski kotar region, sivac on mountain petrova gora and riëice in lika region from croatia, æune in north-western bosnia and herzegovina, the valley of the river krivaja, maëkara district, veovaëa and the environs of kreπevo in the central part of bosnia and herzegovina, and praëa in eastern bosnia and herzegovina, ©uplja stena on avala hill and veliki majdan in serbia, yugoslavia, and stari trg (trepëa) in kosovo, serbia, yugoslavia, are elaborated in this paper. under the research programme, the morphological, as well as relevant crystallographic analyses of the barite crystals, were performed. morphological analysis included goniometric measurement of the crystals, performed for the most part (62 crystals) on a goldschmidt type two-circle reflecting goniometer, and for a smaller number (5 crystals) on a contact goniometer. on the basis of faces determination from a gnomon projection, and by the help of data for barite by goldschmidt (1897) and palache et al. (1951), construction of the parallel perspective drawings of measured crystals was undertaken using the method described by terpstra & codd (1961), as well as the determination of the different habit types of the barite crystals. crystallographic research was performed by the xray powder method on the philips vertical x-ray goniometer with cu kα radiation and graphite monochromator. standard conditions of recording were: 40 kv, 30 ma, 1° 2θ/min for the counter, and 1 cm/min for the recording paper, in the angular region from 9° to 62° 2θ. the barite x-ray diffraction pattern was indexed conformably to jcpds card no. 24-1035. the unit cell dimensions are the result of refinement by the method of least squares performed by the gitter computer program (hummel, 1982) on the base of 28 to 32 indexed diffraction lines. the reticular density of a particular crystal form is the ratio of the number of all atoms in the section of a crystal structure, defined by the elementary parallelogram shkl and interplanar spacing dhkl. the number of all atoms in a certain section was performed by the atoms computer program (dowty, 1991), which gave us the display of structure based on the data (coordinate system, unit cell parameters, space-group symmetry, atom coordinates). the data according to hill (1977) are used for the display of barite structure. the surface of the elementary parallelogram was calculated according to the formula: s2 hkl = h2s2 100 + k2s2 010 + l2s2 001 + 2(hks100s010cosν + kls010s001cosλ + lhs001s100cosµ) where: shkl surface of the elementary parallelogram of the face (hkl) in [å2]; s1 0 0 = b0c0s i nα, s0 1 0 = c0a0s i nβ, s001 = a0b0sinγ (a0, b0, c0 unit cell dimension in [å]; α, β, γ angles between crystal axes); ν = (100) ∧ ( ( 0 1 0 ) ; λ = (010) ∧ (001); µ = (001) ∧ (100)) (phillips, 1946). this formula can be simplified since barite is orthorhombic: s2 hkl = h2b2 0c 2 0 + k2c2 0a 2 0 + l2a2 0b 2 0 according to krivovi»ev (1971) the average structural density of crystal “ecr” was calculated according to the formula: ecr = ∑(m x ehkl) where: m is the morphological persistence of a particular crystal form (frank-kameneckii, 1951), ehkl is the reticular density of a crystal form in number of atoms in å3, and the product “m x ehkl” defines the contribution of reticular density of a given crystal form in the total structural density of crystal. morphological persistence is the ratio of the total surface of all faces of a certain crystal form and the surface of the whole crystal, and was expressed in percent. “m” is calculated thus: face surfaces of emphasized crystal forms were measured on several crystals of a certain habit type, and the average value of these surfaces for a respective crystal form was calculated. the studied barite specimens are stored in the collection of the department of mineralogy and petrography of the croatian natural history museum in zagreb, and are marked by the inventory numbers: 600:zag ;3310:mp1, 600:zag;3602:mp1, 600:zag;3641:mp1, 600:zag;5183:mp1, 600:zag;5677:mp1, 600:zag; 5689:mp1, 600:zag;5718:mp1, 600:zag;5780:mp1, 600:zag;6688:mp1, 600:zag;6691:mp1, 600:zag; 6703:mp1, 600:zag;8541:mp1, 600:zag;8542:mp1, 600:zag;8546:mp1, 600:zag;9013:mp1, 600:zag; 9014:mp1, 600:zag;9016:mp1, 600:zag;9017:mp1, 600:zag;9018:mp1, 600:zag;9021:mp1, 600:zag; 9022:mp1, 600:zag;9023:mp1, 600:zag;9025:mp1, 600:zag;9026:mp1, 600:zag;9027:mp1, 600:zag; 9029:mp1, 600:zag;9030:mp1, 600:zag;9031:mp1 and 600:zag;9039:mp1. 3. results 3.1. morphological analysis from morphological analysis of barite crystals from 12 localities, 8 different habit types were determined. these habit types could be classified into 4 essentially different groups: the eb group of barite crystals (table 1) is represented by 2 habit types elongated in the [010] direction. one habit type was observed only in ©uplja stena, and had been described before (bari∆, 1949). these columnar crystals have prominent {1 0 1} and somewhat smaller {0 1 1} faces. according to braun’s classification, this habit type is intermediate between ore iiib type pb 0 0 1[0 1 0] and carbonate iva type ab ( b r aun, 1932). another habit type was observed in veliki majdan. these columnar crystals have well-developed {0 0 1} and {1 0 1} faces, and somewhat smaller {0 1 1} and {210} faces, and correspond to the carbonate iva type ab (braun, 1932). the ea group of barite crystals (table 2) is represented by 2 habit types elongated in the [100] direction. one habit type was noticed in riëice and kreπevo (raπtelica, dubrave, dusina). these thick-tabular crystals have prominent {001}, {011} and {101} faces, and correspond to the rectangularly-tabular i type 61radanoviê-guævica: the average structural density of barite crystals of different habit types table 1 the average structural density of barite crystals elongated in the [010] direction (eb group). table 2 the average structural density of barite crystals elongated in the [100] direction (ea group). 62 geologia croatica 52/1 pa 0 0 1[1 0 0], [0 1 0] (braun, 1932). another habit type was observed only in the maëkara district. these columnar crystals have well-developed {0 0 1}, {0 1 1}, {101} and {210} faces, and correspond to the carbonate ivb type aa (braun, 1932). the tc group of barite crystals (table 3) is represented by 2 habit types tabular on the basal pinacoid {001}. one habit type was noticed only in æune. these tabular crystals have well-developed faces from the [1 0 0] and [0 1 0] crystallographic axe’s zones, specially table 3 the average structural density of barite crystals tabular on the basal pinacoid {001} (tc group). hab~rtytpe lqcai..jty form m ,~ e'~ mi)l e"", ~. (1ftrim ~ a.~~ i "he~ 001 1i3g.9 3l~1 237''''; ,0111 1:1.5 ~,.,3:j 8 oo.g101 1 ~.6 5.s741 75.2 g_ zum o ~ qo 2,5 2:726 m 394..1 : 2 0. hi 3,. ... 1'12 1ij._~ 100 1.8 4~8 s..i8 201 1.'1 ,3: , n 4,1 001 ,57..3 3..534 2d5..-4, 210 .32'.3 3.440' '11u ~=----j 'di01' 6.7 5.515 ,37.4, ei 'vodi c>!! 2;" 2.4 :u01 7a, ::iiijs.3 010 1..0 2.724 2.7 o'u 0'.34.337 1..3 00 m .ll 9.571 228-9 210 '2<1 _7 3 . .j,3.q, 134 (i,11i) 60.,1 u,25 '7..3 c5jit:~ au :12: ·u~ 13.!.!i v:~~ 2c1 ~ 0..8 3.763 3") 34(1 ,:3 10d 0...7 41 .4129 ,u 101 0_7 5,500 3,~ :291] m 1,678 (ii .i i1jt1d 0..3 2. ;h qj!: 001 55_'2 :1.515 18'1.3 :1l'10 soig 3. 'a1 105.2 ~3 101 1 jj1 5,jim 61.2 1i(jet§~,j) ('iu ~ '1.~32 12,1 977'.2: ~ad 0..3 ~ , oi!\b ~ " f) 6 10 0. 1-4 213 0.1 00,1 5,'1,4 ;j..507~ 184l.q :2:10 39.9 ~4412 1:37.9 10-2 5.1 3..319 15.9 pr.ao!;a 103 2.7 2'.304 !;i,:2 849..1 101 0..7 5..571 9,9 :2&i 1112 3l171 0.8 f.01 ~9, 1 3.,5;76 1:js.9 ~10 2'd.7 3.a36 7>11 .,6 211 , 41.9 3;.007 44,3 201 13.0 3..1liib 49,0 'it msrpbr'l i 111 1!.7 3.1j:w 33b 364,5 101 '3.1 5.$0 6..1 w 1.1 3 .:316 3..6 010 0.6 ,2.720 1..(1. 100 0, 41 4..433 1.s 001 !;)7 . .6, 3 ,811(1, 2£62 210 ~ji; sml ,~ 211 8.a 3.101 :27j) stan trg 1 0 ~ 15.9, 5.!;i71 29 . .15361.41 (li~~ an 1-3 ~.m m om 0.6 2.727 1..6 100 ojl oji ,43'!i 1...~ 63radanoviê-guævica: the average structural density of barite crystals of different habit types {0 1 1} and {1 0 1} faces. another habit type was the most frequent type, and discovered at the following localities: mrzle vodice, æune, veovaëa, kreπevo, praëa, veliki majdan and stari trg (trepëa). these tabular crystals have marked {2 1 0} faces, and correspond to the silicate vi type pb 001[010] (braun, 1932). the ec group of barite crystals (table 4) is represented by 2 habit types elongated in the [001] direction. one habit type was observed only in sivac. these crystals have well-developed {4 1 0} and {1 0 0} faces and somewhat smaller {0 0 1} and {2 1 0} faces, and correspond to the wolnyn vii type ac (braun, 1932). another habit type was noticed only in krivaja. these isometric to elongated crystals have prominent {2 1 0} faces and well-developed {0 0 1}, {1 0 1} and {2 1 1} faces, and correspond to the cubic-pyramidal v type i001,210[120] (braun, 1932). a detailed review of the results of morphological analysis is given in radanovi∆-guævica et al. (in press). 3.2. average structural density of barite crystals the average structural density of crystal was calculated according to aforesaid procedure for 14 barite samples, e.g. 8 different habit types of crystals (tables 1-4). values of the average structural density of a crystal are greatest in the case of barite crystals elongated in the [0 1 0] direction, and amounts vary from 419.5 to 495.8 (table 1). barite crystals elongated in the [1 0 0] direction have values of average structural density in a relatively small range from 415.8 to 431.3 (table 2). values of the average structural density of barite crystals tabular on the basal pinacoid {0 0 1} are 346.3 to 394.1 (table 3). values of the average structural density of a crystal are smallest in the case of barite crystals elongated in the [0 0 1] direction, and range from 276.1 to 349.4 (table 4). the ranges of values of the average structural densities of the four main groups of barite crystal habit types are shown in fig. 1. overlapping of the eb group (barite crystals elongated in the [0 1 0] direction) with the ea group (barite crystals elongated in the [1 0 0] d i r e c t i o n ) was observed, as well as the tc group (barite crystals tabular on the basal pinacoid {0 0 1}) with the ec g r o u p (barite crystals elongated in the [0 0 1] d i r e c t i o n ) . besides, it is necessary to highlight that the value of the average structural density of columnar barite crystals, fig. 1 the ranges of values of average structural densities of four main groups of barite crystal habit types: eb group barite crystals elongated in the [0 1 0] direction; ea group barite crystals elongated in the [100] direction; tc group barite crystals tabular on the basal pinacoid {0 0 1}; ec group barite crystals elongated in the [001] direction. table 4 the average structural density of barite crystals elongated in the [001] direction (ec group). 64 geologia croatica 52/1 elongated in the [0 1 0] direction, with well-formed {1 0 1} and {0 0 1} faces, as well as with somewhat smaller {2 1 0}, {2 0 1} and {0 1 1} form faces, which were noticed in veliki majdan mine is very close to the value of average structural density of columnar crystals elongated in the [1 0 0] direction, with well-formed {0 1 1} and {0 0 1}, as well as with somewhat smaller {1 0 1} and {2 1 0} form faces, from maëkara district. according to braun’s classification, both habit types correspond to the carbonate type, i.e. crystals elongated in the [010] direction are carbonate iva type ab, and the crystals elongated in the [100] direction are carbonate ivb type aa (braun, 1932). 4. discussion and conclusions by comparison of the values of average structural densities of different habit types of barite crystals, the development sequence of barite crystal types in consideration to a decrease of average structural density, was determined. in general, the priority sequence was: barite crystals elongated in the [0 1 0] direction (eb group) barite crystals elongated in the [1 0 0] direction (ea group) barite crystals tabular on the basal pinacoid {001} (tc group) barite crystals elongated in the [001] direction (ec group) (fig. 1). from similar previous researches (solodovnikova, 1927; seager & davidson, 1952; krivovi»ev, 1971; zebec, 1976), together with the one performed here, it is possible to conclude that the sequence of developing of barite crystal types is not strictly defined, and is changeable (alternate) from case to case. besides the density of the atomic arrangement, which defined the development sequence of crystal habit types, there are many other factors, which are able to cause a change in the sequence, or a change of direction. it would be of great interest to know something about the mineral associations in which particular habit types of barite crystals occur, since the morphology of barite crystals together with information on mineral association, can help identify conditions under which some mineral assemblages were formed. however, research on mineral associations, as well as comparison with braun’s group was beyond the scope of this paper and is left for future investigation. acknowledgements i would like to thank academician stjepan ©∆avni»ar for his helpful and expert advise during the elaboration of the master’s thesis, and comments on the manuscript. 5. references bari∆, lj. (1949): nekoliko rijeëi o obliku baritnih kristala odnosno njima korespondentnim πupljinama u kremenom materijalu sa ©uplje stene na avali nedaleko beograda (quelques remarques sur la forme des cristaux de baryte, ou des cavités correspondantes, dans les quartz de ©uplja stena dans l’avala, aux environs de belgrade).geol. anali balkan. pol., 17, 66-72, beograd. braun, f. (1932): morphologische, genetische und paragenetische trachtstudien an baryt.neues jahrbuch miner. abh., 65, 173-222. bravais, m.a. (1851): du cristal considéré comme un simple assemblage de points.j. ec. polytech., 20/34, 101-193. dowty, e. (1991): atoms a computer program for displaying atomic structures, ibm-pc version 2.1.shape software, kingsport. fernandez-diaz, l., putnis, a. & cumberbatch, j. (1990): barite nucleation kinetics and the effect of additives.eur. j. mineral., 2, 495-501. frank-kameneckii, v.a. (1951): mineralogija i kristalografija barita iz æil v verhovijah reki kubanji.zap. vses. miner. obshch., 80, 33-47. goldschmidt, v. (1897): krystalographische winkeltabellen.verlag von julius springer, berlin, 6062. hill, r.j. (1977): a further refinement of the barite structure.can. mineral., 15, 522-526. hummel, w. (1982): bestimmung von gitterparametern aus pulverdiagrammen nach m. mayr.linzradex-rundsch., 4/81, 682. kostov, i. (1966): veranderungen des kristallhabitus von mineralen mit rutil-struktur.ber. deutsch. ges. geol. wiss., 11, 295-304. kostov, i. (1969): habit types and crystallogenesis of diaspore and goethite.annuaire de l’universite de sofia, 61, 167-176. kostov, i. (1970): habitusi i genezis polimorfnih modifikacii al2s i o5.problems of petrology and genetic mineralogy, sobolev’s vol., ii, 157-160. kostov, i. (1975): apophyllite morphology as an example of habit modification of planar crystals.neues jahrbuch miner. abh., 123/2, 128-137. krivovi»ev, v.g. (1971): k kristallomorfologiji barita beloreëenskogo mestoroædenija.zap. vses. miner. obshch., 100, 462-470. palache, c., berman, h. & frondel, c. (1952): the system of mineralogy, vol. ii.7th edition, john wiley & sons inc., 408-415, chapman and hall, ltd., new york london. 65radanoviê-guævica: the average structural density of barite crystals of different habit types phillips, f.c. (1946): crystal habit.in: an introduction to crystallography. longmans, green and co. ltd., london, 295-311. prieto, m., putnis, a., arribas, j. & fernandez-diaz, l. (1992): ontogeny of baryte crystals grown in a porous medium.miner. mag., 56, 587598. radanovi∆-guævica, b. (1995): morfoloπke i kemijske znaëajke barita odabranih iz zbirke hrvatskog prirodoslovnog muzeja u zagrebu (morphological and chemical characteristics of barite selected from the collection of croatian natural history museum in zagreb).unpublished m.sc. thesis, university of zagreb, 152 p. radanovi∆-guævica, b., ©∆avni»ar, s. & zebec, v. (in press): a new crystallographic feature of barite from the balkan peninsula.neues jahrbuch miner. seager, a.f. & davidson, w.f. (1952): changes in habit during the growth of baryte crystals from the north of england.miner. mag., 29, 885-894. solodovnikova, l.l. (1927): bariti tjuja-mujunskogo rudnika.trudi min. muzeja an sssr, 2, 37-90. terpstra, p.d. & codd, l.w. (1961): crystallometry.longmans, london, 420 p. truebe, h.a. (1981): water-clear barite from muddy creek, colorado.miner. record, 12, 79-80. zebec, v. (1976): barit i kalcit iz kamenoloma litotamnijskog vapnenca u krapinskim toplicama u hrvatskom zagorju (baryt und calcit aus dem leithakalksteinbruch in krapinske toplice in hrvatsko zagorje (kroatien, jugoslawien)).geoloπki vjesnik, 29, 323-345. manuscript received may 22, 1998. revised manuscript accepted may 28, 1999. 66 geologia croatica 52/1 in memoriam mr. sc. ante reni∆ (1948 2000) u automobilskoj nesreêi 31.08.2000 godine poginuo je naπ kolega i prijatelj mr. ante reniê. vijest o nesreêi primili smo s nevjericom, kao i brojni prijatelji i poslovni suradnici, posebno oni iz dalmacije i like gdje je proveo najveêi dio svog terenskog rada. tog kobnog jutra u automobilu je bila cijela obitelj. u sudaru s iznenada preprijeëenom kamionskom prikolicom na cesti kod koprivnice, uz mr. reniêa poginule su supruga, majka i mlaa kêerka. ante reniê je roen 19.10.1948. godine od oca boæe i majke magdalene u deëinu, republika »eπka. doselio je 1951. s roditeljima u bjelovar. osnovnu πkolu i gimnaziju je polazio u bjelovaru, gdje je maturirao 1969. godine. iste godine je upisao na geoloπkom odjelu prirodoslovno-matematiëkog fakulteta u zagrebu grupu geologija i paleontologija. diplomirao je 1977., a od svibnja 1978. godine zaposlen je u institutu za geoloπka istraæivanja, zavodu za hidrogeologiju i inæenjersku geologiju. radio je na hidrogeoloπkim i inæenjerskogeoloπkim istraæivanjima u krπkim podruëjima like, dalmacije, otoka te juæne bosne. nakon zavrπetka poslijediplomskog studija obranio je u studenom 1989. magistarski rad “hidrogeoloπki odnosi u slivu izvora rijeke krke kod knina”. sve godine rada putovao je svakodnevno iz bjelovara u zagreb, ne æeleêi se odvajati od posla kojeg je volio ali ni od obitelji o kojoj se nesebiëno brinuo. skladan æivot s roditeljima, æenom editom, kêerkama helenom i vlatkom povezao je s obavezama na poslu koji je zahtjevao posebne napore s obzirom na dugotrajne boravke na terenu. u sklopu struënog tima i samostalno, sudjelovao je u izradi hidrogeoloπkih i inæenjerskogeoloπkih podloga za potrebe projektiranja hidroenergetskih objekata u krπu akumulacija, brana, vodozahvata, tunela, zaπtite voda, kao i viπe studija utjecaja pojedinih objekata na podzemne vode. bio je voditelj listova drniπ i sinj osnovne hidrogeoloπke karte hrvatske. autor je viπe od 80 struënih radova, studija i elaborata. suraivao je na dva projekta ministarstva znanosti i tehnologije: osnovna hidrogeoloπka karta republike hrvatske i hidrogeoloπka osnova za zaπtitu voda jadranskog sliva. radom na mnogim zadacima detaljno je upoznao hidrogeoloπku problematiku krπkih terena, pa je bilo nezamislivo rjeπavanje bilo kojeg hidrogeoloπkog probg eol. croat. 53/2 307 309 zagreb 2000 our colleague and friend ante reniê, m.sc. geol. was born on october 19, 1948, and died in a traffic accident on august 31, 2000. he finished his elementary and high school education in bjelovar, where he graduated in 1969. in 1977 he obtained a b.sc. degree in geology, at the geological department of the faculty of science, university of zagreb. from may 1978 until his death he was employed at the institute of geology, zagreb, department of hydrogeology and engineering geology. he worked on hydrogeological and geological engineering investigations of the karst areas of lika, dalmatia, the adriatic islands and southern bosnia. after completing his post-graduate studies he obtained the degree of m.sc. in 1989 with a thesis entitled “hydrogeological relations in the catchment area of the krka river near knin”. as either a member of a professional team or an individual, he participated in hydrogeological and geological engineering investigations during the planning of several hydroenergy projects in the karst area, including the construction of accumulations, dams and water intake structures, and water protection measures, as well as several studies on the influence of particular objects on groundwater. he was author or co-author of more than 80 professional papers, studies and reports. ante reniê also collaborated on two projects financed by the ministry of science and technology of the republic of croatia; the basic hydrogeological map of the republic of croatia (he was head of the investigations for two sheets, drniπ and sinj) and the hydrogeological basis for protection of waters of the adriatic catchment area. his wealth of experience and collected data resulted in the publication of several of his papers in scientific journals and proceedings of croatian and foreign professional meetings. 308 geologia croatica 53/2 lema na podruëju dalmatinskih slivova a da nije sudjelovao i kolega reniê. iz bogatog iskustva i prikupljenih podataka objavio je kao autor i koautor radove u znanstvenim ëasopisima i zbornicima struënih skupova odræanih u tuzemstvu i inozemstvu. svojom pedantnoπêu i sistematiënoπêu u radu priskrbio je poπtovanje i povjerenje kolega s kojima je radio, te suizvoaëa i investitora. gotovo se nije moglo zamisliti programiranje novih radova u tom πirokom podruëju bez njegovog sudjelovanja. u podruëju naπeg krπa mr. reniê je bio ukljuëen u hidrogeoloπke radove na veêini hidroenergetskih objekata koji se danas koriste ili je radio istraæne radove za projektnu dokumentaciju za buduêe objekte. meu ostalim radio je na novim objektima koji su u proizvodnji he –ale, rhe obrovac (rhe velebit), ili na odræavanju ranije izgraenih objekata he senj, he sklope, he manojlovac, he ozalj, he kraljevac. sudjelovao je u izradi hidrogeoloπkih podloga mnogih objekata koji su u raznim stupnjevima projektiranja he krëiê, he tisne stine, he zrmanja, he æegar, he »ikola, he kosinj, he ombla i dr. u posljednjih desetak godina uz osnovnu djelatnost na hidrogeoloπkim projektima i istraæivanjima za hidroenergetske objekte posebno se bavio hidrogeoloπkim istraæivanjima vezanim uz koriπtenje i zaπtitu krπkih izvorskih i podzemnih voda. naëinio je ili sudjelovao u timu istraæivaëa pri izradi hidrogeoloπkih podloga za odreivanje zona sanitarne zaπtite brojnih crpiliπta pitke vode crpiliπta zadarskog vodovoda, izvora jadro i ærnovnica kod splita, jurjeviêa izvorstudenci, izvora ©ilovka, kosinac, mala ruda (u slivu cetine) samo su neka od njih. u okviru zaπtite podzemnih krπkih voda izveo je brojne detaljne radove “mikrozoniranja” unutar osnovnih zona zaπtite, a vezano uz otvaranje kamenoloma, benzinskih postaja i odlagaliπta otpada. to pripada meu prve radove takove vrste, pa mogu posluæiti kao predloæak za rjeπavanje ove problematike u πirem krπkom podruëju. brojni struëni radovi sadræe podatke nezaobilazne kod prouëavanja hidrogeoloπke problematike podruëja i lokaliteta na kojima je radio mr. reniê. u radovima pohranjenim u fondu dokumenata instituta za geoloπka istraæivanja saëuvani su brojni podaci i izneπena miπljenja o hidrogeoloπkoj problematici krπa koju je kolega reniê dobro poznavao. uz ostalo tu su podaci o brojnim trasiranjima podzemne vode u podruëju like i dalmacije, koje je osobno izveo, ali i prikupio iz ranije izvedenih radova. bogato terensko iskustvo upotpunio je sistematskim pristupom izradi radova od programiranja do prikupljanja dostupne literature, obrade terenskih podataka i prezentacije u izvjeπêima. svi oni koji êe ubuduêe raditi na tom podruëju obavezno êe morati posegnuti za radovima mr. reniêa. tragiëna smrt ga je prekinula u vrijeme kad je pripremao doktorsku disertaciju pod naslovom “hidrogeoloπki temelji zaπtite podzemne vode u jadranskom slijevu podruëja jugoistoëne like, juæne bosne i sjeverozapadne dalmacije”. u disertaciji je æelio objediniti znanje koje je stekao kroz brojne struëne radove, gdje je detaljno upoznao hidrogeoloπku grau terena. spoznajom o hidrogeoloπkim odnosima i utjecaju razvitka danaπnjeg reljefa na propusnost stijena, uz koriπtenje rezultata hidroloπkih, meteoroloπkih, geofiziëkih i drugih znanstvenih disciplina, razradio je πiroko krπko podruëje jadranskog sliva. æelio je istaknuti vaænost toënog definiranja slivova kao nezaobilaznu osnovu u rjeπavanju stvarnih potreba gospodarenja vodama. istakao je potrebu podjele jadranskog sliva na hidrogeoloπke slijevove kojima su danaπnje erozijske baze hidrogeoloπke barijere ili razina mora, πto omoguêuje pouzdaniju zaπtitu povrπinskih, a osobito podzemnih voda, te racionalno praêenje kvalitete vode u slijevovima crpiliπta pitke vode. posebnu aktivnost je pokazao u vrijeme odræavanja 2. hrvatskog geoloπkog kongresa, gdje je osim rada “moguênost vodopskrbe iz slijeva izvora uz istoëni obod kninskog polja” bio izuzetno aktivan u pripremanju hidrogeoloπkog dijela vodiëa ekskurzije kroz podruëje dalmacije. uz tekstualne prikaze o slivu cetine, hidroelektrani –ale i izvorima jadra i ærnovnice uspjeπno je vodio terenski dio ekskurzije. institut za geoloπka istraæivanja je smrêu mr. ante reniêa izgubio vrsnog hidrogeologa u vrijeme kad je u znanstvenom i struënom dijelu mogao joπ puno toga doprinjeti u razvitku spoznaja o hidrogeologiji i zaπtiti krπkih podzemnih voda i koriπtenja terena. naæalost, tragiëna smrt ga je prekinula u naponu snage, na polovici radnog vijeka, kad je mogao bogato terensko iskustvo joπ upotpuniti i prenijeti u izvjeπêa i znanstvene radove. mi stariji djelatnici instituta za geoloπka istraæivanja izgubili smo iskusnog suradnika, kolegu i prijatelja. mlaim kolegama uskraêena je moguênost da im mr. reniê direktno prenese saznanja o terenu u kojem je radio i znanje koje je o krπkom terenu stekao. neka je hvala i slava mr. reniêu, naπem anti, kojeg êemo se s poπtovanjem trajno sjeêati. ante pavi»i∆ 309in memoriam: ante reni∆ popis objavljenih radova boæi»evi∆, s., pavi»i∆, a. & reni∆, a. (1983): pojava vodenog toka u spiljskom sistemu ispod sedrene barijere.i jugosl. simp. o inæ. hidrologiji, 1, 251-261, split. boæi»evi∆, s., reni∆, a. & zebec, v. (1984): obiljeæja nekih speleoloπkih objekata i analiza pukotina u tunelu kroz juæni velebit.viii jug. simp. za hidrogeol. i inæ. geol., 2, 277-285, budva. reni∆, a., pavi»i∆, a. & kapelj, j. (1986): possibilities of frequent tracings with fluorescein in the drainage area of high-yielding karst springs in croatia.5th international symposium on underground water tracing, abstracts, 58-59, athens. reni∆, a., pavi»i∆, a. & fritz, f. (1988): geoloπka podloga za izvedbu tunela u krπu na primjeru dovodnog tunela rhe obrovac.i jugosl. simp. o tunelima, 1, 201-203, brioni. fritz, f., pavi»i∆, a. & reni∆, a. (1990): porijeklo voda u nacionalnom parku “krka”.simpozij np krka stanje istraæenosti i problemi zaπtite ekosistema, 2, 115-126, zagreb. pavi»i∆, a. & reni∆, a. (1992): recent karstification and water drainage from bakovac valley (lika, croatia).international symp. geomorphology and the sea, 127-133, mali loπinj. fritz, f., reni∆, a. & pavi»i∆, a. (1993): hydrogeology of the hinterland of ©ibenik and trogir, croatia.geol. croat., 46/2, 291-306. reni∆, a. (1994): zaπtita krπkih podzemnih voda od objekata uz prometnice.priopêenja savjetovanja geotehnika prometnih graevina, 1, 357-363, zagreb. pavi»i∆, a. & reni∆, a. (1995): utjecaj liëkih ponornih voda na priobalne izvore.1. hrvatska konferencija o vodama, dubrovnik, 2, 23-29, zagreb. pavi»i∆, a. & reni∆, a. (1995): moguênosti vodoopskrbe iz liëkog dijela sliva rijeke zrmanje.1. hrvatski geoloπki kongres, opatija, zbornik radova, 2, 435-438,zagreb. reni∆, a. & pavi»i∆, a. (1999): utjecaj sedrene barijere na krπki izvor.2. hrvatska konferencija o vodama, zbornik radova, 559-564, dubrovnik. reni∆, a. & pavi»i∆, a. (2000): moguênosti vodoopskrbe iz slijeva izvora uz istoëni obod kninskog polja.2. hrvatski geoloπki kongres , cavtatdubrovnik, zbornik radova, 755-759, zagreb. buljan, r., ivi»i∆, d., jurak, v., markovi∆, t., pavi©a, t., reni∆, a. & ©estanovi∆, s. (2000): hidrogeoloπki i inæenjerskogeoloπki prikaz odabranih lokaliteta u podruëju dubrovaëkog primorja.2. hrvatski geoloπki kongres, cavtat-dubrovnik, vodië ekskurzija, 13-32, zagreb. ivi»i∆, d., bahun, s., buljan, r., boæi»evi∆, s., pavi»i∆, a., pavi©a, t. & reni∆, a. (2000): hidrogeologija i geomorfologija krπa vanjskih dinarida.2. hrvatski geoloπki kongres, cavtat-dubrovnik, vodië ekskurzija, 55-92, zagreb. gjetvaj et al..indd 1. introduction construction of a waste disposal site necessarily involves implementing an effective barrier which is intended to isolate waste from the sub-base and minimize the transport of contaminants from the site to an aquifer. natural clayey deposits and compacted clay liners with pehd geomembranes are the barrier liners that are generally used. but, in some regions, the croatian karst for example, clay is not available in sufficient quantities and, consequently, other natural materials should be considered. therefore, the use of pulverized stone (the by-product in the building-stone industry) as a potential liner material was investigated. the properties of pulverized stone were compared to those of the novačica clay (the clay which was used for the barrier liner applied in the jakuševec landfill) and of a geosynthetic clay liner (gcl), the material which is usually used in “clayless” regions. diffusion through pulverized stone compared to other mineral barrier materials goran gjetvaj1, predrag kvasnička2 and želimir veinović2 the transport of contaminants through porous media such as clay, pulverised stone and a gcl, which are used as barriers, may be the result of only two physical processes, namely convection and molecular diffusion. since migration of chemical substances through barriers caused by convection is negligible, diffusion is a dominant mechanism of contaminant transport. the transport (caused by diffusion) of an observed tracer in a solution can be described by fick’s first law (dagan, 1989): , where: qm is the flow of a tracer caused by diffusion [m/l2t], dm is the diffusion coefficient of the observed matter in a given solvent [l2/t], is hamilton’ s operator [1/l], c is the concentration of the observed tracer [m/l3]. the transport of contaminants in barrier liners caused by diffusion is slower than in a free solution because of the reduced cross-sectional area of flow and the more tortuous pathways for migration in a porous medium, i.e. barrier. in addition, the rate of transport can be further reduced by the interaction of the contaminants and the walls of the porous medium, i.e. absorption reactions. hence, the effective diffusion coefficient (dm e) should be defined as follows dagan (1989): , where: dm e is an effective molecular diffusion coefficient in a porous medium [l2/t], f(n) is a function dependent on a porous medium. 2. methods and apparatus the diffusion of contaminants in a saturated sample was studied under laboratory conditions (t = 20ºc) with nacl solution as a tracer. since the electrical conductivity of an nacl solution of low concentrations is linearly proportional to the ion concentration in water, the nacl concentration can be determined by measuring the electrical conductivity of the solution. the apparatus for measuring diffusion (fig. 1) consisted of two beakers of different sizes, placed one inside the other (rowe et al., 1995). the inner geologia croatica 57/1 95–101 6 figs. 3 tabs. zagreb 2004 key words: diffusion, pulverized stone, mineral barrier. 1 faculty of civil engineering, university of zagreb, kačićeva 26, hr-10000 zagreb, croatia; e-mail: goran@grad.hr 2 faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, hr-10000 zagreb, croatia; e-mail: pkvasnic@rgn.hr; zveinovic@rgn.hr abstract construction of a waste disposal site requires an effective barrier that separates waste from a sub-base and minimizes the migration of contaminants from the site to an aquifer. barrier layers most often used are natural clayey deposits or compacted clay liners and pehd geomembranes. however, some regions, the croatian karst for example, are mostly short of clay. for this reason, the use of pulverized stone, the by-product in the building-stone industry – as a potential liner material was investigated. considering diffusion is an important mechanism of contaminant transport through barriers, this paper describes the method and apparatus for determining the diffusion coefficient of pulverized stone. measured diffusion values were related to sample compaction and compared with the physical properties of clay, geosynthetic clay liners and pehd geomembranes. other physical properties of pulverized stone such as the filtration coefficient, density and particle size distribution are also presented. finally, the suitability of pulverized stone for barrier construction is discussed based on the results obtained. 96 geologia croatica 57/1 97gjetvaj, kvasnička & veinović: diffusion through pulverized stone compared to... beaker with an inside diameter d = 86 mm and a height h = 150 mm was suspended from the rim of the outer beaker having an inside diameter d = 160 mm and a height h = 257 mm. the bottom of the inner beaker was removed, and a corrosion-resistant net or a piece of filter paper inserted instead to prevent the sample from scattering. both beakers were made of laboratory glass that does not react with the solutions used for measurement. the beakers were filled with water, and the water surface in both beakers was maintained at the same level for the duration of measurement to prevent the transport of the tracer by convection. the experiment started by feeding the given amount of the tracer into the inner beaker. due to differences in the concentration of solutes on the sides of the sample (the concentration gradient), the tracer passed through the sample into the outer beaker. the rate of transport depends on the concentration gradient. the transport of the tracer through the sample can be described by fick’s law. the transport from the inner beaker through the sample (q1) can be expressed as: , where a is the effective sample area. the transport from the outer side of the sample (q2) is: , and thus the change in the tracer quantity in the sample is: on the basis of which a change in concentration in time can be expressed: . the last equation is known as fick’s second law. this law was applied in this paper for solving the inverse problem, i.e. the diffusion coefficient was calculated on the basis of the measured change in concentration with time. 3. tested samples of barrier layers 3.1. pulverized stone barrier layers used for the construction of landfills are usually made of clay. however, clay is not available in sufficient quantities in some areas including the karst region for example. therefore, the barrier properties of pulverized stone (refuse in the stone industry and a potential barrier material), were studied. it was expected that, in combination with some additives, pulverized stone could be used for the construction of barrier layers. fig. 1 the laboratory apparatus. 96 geologia croatica 57/1 97gjetvaj, kvasnička & veinović: diffusion through pulverized stone compared to... the physical properties of pulverised stone were found to be as follows: particle density ρs = 2.96 g/cm3, water content w = 33%, liquid limit wl = 46.24%, plastic limit wp = 29.04%, and plasticity index ip = 17.20%. figure 2 shows the particle-size distribution of the pulverized stone samples. the filtration coefficient was measured by veinović & kvasnička (2000) and is given in table 1 together with the consolidation pressure values. pulverized stone was inserted into the apparatus using a hammer and different compaction energies were applied, which resulted in dry densities of 1.55, 1.56 and 1.57 g/cm3 (table 2). the sample thickness was measured after insertion and was 1.2±0.1 cm. 3.2. the novačica clay for the purpose of determining the diffusion coefficient of the novačica clay, the clay samples were compacted by applying the same three compaction energies as those applied to the pulverized stone; dry densities for pulverized stone and clay vs. degree of compaction are given in table 2. it should be noted that the dry density of a well-compacted material is roughly equal to the maximum dry density obtained by compaction according to the proctor standard. the physical properties of the novačica clay, obtained by testing, are as follows: particle density ρs = 2.72 g/cm3, natural water content w = 21.0%, liquid limit 63.5%, plastic limit 21.2% and plasticity index 42.3%. filtration coefficient is 1.32x10–10 m/s. hence, the novačica clay meets all the requirements set by designer for barrier layers. 3.3. geosynthetic clay liner (gcl) in addition to the diffusion coefficients of clay and pulverized stone, the research dealt with determining the effective diffusion coefficient of a commercially available gcl. after being saturated with water under laboratory conditions, the tested gcl sample may experience significant changes in volume and, as a result of this, a change in properties. for this reason, the measuring apparatus was further equipped with two steel plates to prevent the sample from undesirable swelling. as compared to other tests in this paper, there was no possibility of testing samples with different densities, only the effective diffusion coefficient value is presented. 3.4. sand–clay gel-mixture (trisoplast®) among the alternative materials for barriers, a coefficient of diffusion for a single sand–clay gel mixture was measured. the chosen product was an industrial material called trisoplast®, produced with a patented technology developed by gid milieutechniek (the netherlands; www.trisoplast.nl). the material consists of a clay gel mixed with a filler, e.g. sand. as soon as water penetrates the mixture, the clay gel is formed consolidation pressure filtration coefficient (kn/m2) (cm/s) 50 6.66 x 10-7 100 6.30 x 10-7 200 5.84 x 10-7 400 5.12 x 10-7 table 1 filtration coefficients of the tested pulverized stone. degree of pulverized stone clay compaction density density poorly compacted 1.55 1.77 well compacted 1.56 1.92 very well compacted 1.57 1.96 table 2 degree of compaction versus sample density (g/cm3). fig. 2 a particle-size distribution curve of pulverised stone. 98 geologia croatica 57/1 99gjetvaj, kvasnička & veinović: diffusion through pulverized stone compared to... from a mixture of clay minerals (bentonite) and polymers. a dense gel structure is created as a result of the presence of a network of chemical bonds between the clay mineral particles and polymers. the mixture has better barrier properties than traditional mineral barriers and it also allows far less water to permeate through it (at least 100 to 1,000 times less than traditional mineral barriers). the mixture is used as a barrier in landfills, industrial sites, tank farms, reservoir basins, washing facilities, manure storage, etc. the producer suggests much thinner sealing layers can be used than those required for standard clay liners, because the mixture has a very low permeability. it is very plastic, with chewing-gum-like properties. when traditional mineral sealing materials are used, insufficient plasticity means that cracks can occur in the sealing layer if there is rapid and irregular subsidence. as the layer of the mixture can deform and stretch, it is able to follow soil deformation and subsidence. the large swelling capacity of the clay gel gives the mixture a large self-healing capacity in the event of damage. at the same time, clay minerals cannot be washed out because of the bonds with polymers. according to weitz et al. (1997) the plastic limit of the mixture is 36%, the liquid limit is 179% and therefore, the plasticity index is 143%. the proctor dry density for the standard mixture is 1.680 g/cm3, and the optimum water content is 16%. in the same report, the average diffusion coefficient was reported to be 4.0x10-10 m2/s. the diffusion coefficient for chloride varies from 1 to 8x10-10 m2/s. 3.5. pehd geomembrane this research did not include testing of a pehd geomembrane; the only reason was because the apparatus used was unsuitable for measuring the diffusion coefficient of the pehd geomembrane, as its value is much lower than those of the other tested materials for which the apparatus was originally designed. for information, the diffusion coefficients for the transport of toluene and xylene through the pehd geomembrane found in professional literature are dm e = 5.1x10-13 m2/s and dm e = 1.0x10-13 m2/s respectively (prasad et al., 1994). 4. measurement results as the measuring technique was found to be suitable for this research, the diffusion coefficient tests were carried out for the samples of clay from the novačica site, pulverized stone, trisoplast® and the gcl. exact density values of the sample materials, the water volume in both the inner and outer beakers, and the temperature and change in electrical conductivity were measured in each test. the measuring apparatus was set after the sample fig. 3 changes in solute concentration in the inner beaker for the pulverized stone sample. 98 geologia croatica 57/1 99gjetvaj, kvasnička & veinović: diffusion through pulverized stone compared to... was inserted and water added to achieve steady state conditions. then, 2 g of nacl were fed into the inner beaker, which resulted in the increase in concentration of the solution contained in the inner beaker. the rate of reduction in concentration of solutes in the inner beaker with time was measured (fig. 3). the gradual increase in ion concentration in the outer beaker over the next few days was measured. based on the research results, the mean values of the effective diffusion coefficient for pulverized stone were measured (table 3). the same test was carried out with clay used for barrier liners. the results are shown in fig. 4 which presents a decrease in the tracer concentration in the inner beaker for three samples which were inserted by applying different compaction energies. the graph shows that the clay sample having highest density is the least permeable, as expected. a mean value of the effective diffusion coefficient for the novačica clay was calculated on the basis of the test results (table 3). the effective diffusion coefficient was also measured for trisoplast®. the results are shown in fig. 5 and table 3. the graph shows that all three samples, compacted to different densities, have almost the same effective diffusion coefficient. in addition to pulverized stone, and trisoplast®, a sample of gcl was also tested using the same measuring apparatus. based on the measurements taken and the interpretation of the results, the effective diffusion coefficient of gcl was computed as dm e = 6.06x10-10 m2/s. these results are shown in table 3 together with the effective diffusion coefficient values for the pehd geomembrane taken from the literature. compaction vs. fig. 4 change in nacl concentration in the inner beaker for the clay sample. degree of pulverized clay trisoplast® gcl pehd compaction stone geom. poorly 3.22x10-10 2.06x10-10 2.64x10-10 5.1x10-13 well 2.92x10-10 1.98x10-10 2.59x10-10 6.06x10-10 to very well 2.38x10-10 1.78x10-10 2.60x10-10 1.0x10-13 table 3 effective diffusion coefficients, dme (in m2/s) of different barrier materials. 100 geologia croatica 57/1 101gjetvaj, kvasnička & veinović: diffusion through pulverized stone compared to... effective diffusion coefficients, dm e , for different barrier materials are presented in fig. 6. while samples of clay, pulverized stone and trisoplast® have similar values, the gcl diffusion coefficient was two orders of magnitude lower than that of the other tested materials. 5. conclusions when making a decision on the selection of a material for a barrier liner to be used in sanitary landfills, it is also necessary to be aware of the quantity of contaminants transported due to the diffusion process. although the quantity of contaminants transported in this way is relatively low, this quantity can be important in the case of highly toxic substances or for nearby aquifers holding low water quantities. the transport of substances induced by diffusion is defined by fick’s laws that explain that the transported quantity of contaminants depends on the effective diffusion coefficient of a barrier layer, i.e. the shape and volume of pores, and also the thickness of the layer. the paper deals with test results carried out to determine effective diffusion coefficients for clay from the novačica site, pulverized stone (the by-product in the stone industry), trisoplast® and a type of gcl in commercial use. for the purposes of measurement, an apparatus intended for these materials was designed. the results obtained were compared with data on the effective diffusion coefficient of a pehd geomembrane taken from literature. in sample preparation, different compaction energies were applied and the relationship between the diffusion coefficient and the compaction of the sample was observed. as the sample compaction increased so the effective molecular diffusion coefficient decreased, which was particularly noticeable in the case of pulverized stone. well-compacted pulverized stone has an effective molecular diffusion coefficient roughly equal to that of clay and, therefore, can be used for the construction of barrier liners. prior to applying pulverized stone for barrier liners, the transport of pollutants by convection should be studied. if necessary, additives or some other technical solutions should be applied to prevent possible pollutant transport through the pulverized stone liner. considering its use in barriers, as opposed to industrial products, pulverised stone is expected to be built in a thick layer, as much as 1.0 m or more (like clay). although the diffusion coefficients of pulverised stone and industrial products are of similar values, because of the layer thickness, cumulative diffusion transport through the pulverised stone layer should be much less than the transport through industrial products. fig. 5 change in nacl concentration in the inner beaker for trisoplast®. 100 geologia croatica 57/1 101gjetvaj, kvasnička & veinović: diffusion through pulverized stone compared to... 6. references dagan, g. (1989): flow and transport in porous formations.– springer-verlag, berlin, 465 p. prasad, t.v., brown, k.w. & thomas, j.c. (1994): diffusion coefficients of organics in high density polyethylene.– waste management & research, 12, 61–71. rowe, r.k., quigley, r.m. & booker, r.j (1995): clayey barrier systems for waste disposal facilities.– e&fn spon, london, 390 p. fig. 6 compaction vs. effective diffusion coefficient values, dme, for different barrier materials. veinović, ž. & kvasnička, p. (2000): possible application of waste stone dust for sanitary landfill liners.– vith international symposium waste management – zagreb 2000, proceedings, 1, 323–332. weitz, a.m., boels, d. wiegers, h.j.j. & eversvermeer, j.j. (1997): application of trisoplast for lining of landfills.– winand staring centre for integrated land, soil and water research, agricultural research department, report 142, wageningen. manuscript received october 15, 2002. revised manuscript accepted may 04, 2004. 102 geologia croatica 57/1 plint.indd clastic sediment partitioning in a cretaceous delta system, western canada: responses to tectonic and sea-level controls a. guy plint 1. introduction sedimentary successions record only three possible conditions: deposition, bypass or erosion. various questions attend each option: if deposition took place, what were the processes, at what rate did they occur, and did the rates change over time? if non-deposition or bypass is indicated, then for how long, and why? if erosion occurred, what was the process, how much sediment was removed, and over what interval of time? these questions could be addressed in an ‘ideal’ stratigraphic succession that contained numerous, accurately-dated layers, and in which physical sequence-bounding surfaces and the main facies enclosed between those surfaces could everywhere be mapped. in reality, these requirements are rarely met in ancient sedimentary successions. perhaps one of the best opportunities to investigate the details of a basin’s history is offered by the mesozoic strata of the western canada sedimentary basin. this clastic-dominated basin extends northward into the nw territories, and southward through the western united states to the gulf of mexico. the basin evolved from a divergent margin in the palaeozoic to a retro-arc foreland basin in the late jurassic. in canada, the palaeozoic and mesozoic strata in this basin contain abundant oil and gas reserves which have been extensively investigated through several hundred thousand boreholes. fair to excellent quality well logs are publicly available for every well, and abundant core has been cut from reservoir intervals. although seismic sections are numerous, they are not publicly available. these rocks are also extensively exposed along the western margin of the basin in thrust sheets that form the front ranges and foothills of the rocky mountains. correlation of well logs in the basin to outcrop sections in the mountains not only allows logs to be calibrated against exposed lithologies, but also allows isolated outcrop sections to be placed in a regional stratigraphic and palaeogeographic framework. the main deficiency of the stratigraphic record is the relative paucity of well-dated stratigraphic marker horizons, although marine strata yield fossils that can, in the cretaceous part of the section, provide relative age resolution of about 0.5 ma. geologia croatica 56/1 39–68 31 figs. zagreb 2003 key words: cretaceous, cenomanian, western canada, foreland basin, deltas, sea-level change, tectonics, eustasy, clastic sedimentation, sequence stratigraphy. department of earth sciences, university of western ontario, london, ontario n6a 5b7, canada; e-mail: gplint@uwo.ca abstract the early–mid cenomanian dunvegan formation represents a large delta complex that prograded at least 400 km from nw to se. a regional stratigraphy based on marine transgressive surfaces and equivalent subaerial interfluves allows the formation to be subdivided into ten transgressive–regressive allomembers, labelled j to a in ascending order, each with an average duration of < 200 ky. analysis of stacking patterns and facies distributions of parasequences within allomembers allows transgressive, highstand, falling stage and lowstand systems tracts to be identified. extensive valley systems that average 1–2 km wide and 21 m deep can be traced for up to 320 km across the top surfaces of allomembers h to e. in their lower 20–40 km, valleys are filled with muddy heterolithic tidal facies but this changes to fluvial-dominated multi-storey channel-fills further up-valley. interfluve surfaces are marked by palaeosols, the character of which indicate a protracted hiatus with extensive physical, chemical and biological modification of the parent material. changes in flexural subsidence rate are indicated by isopach patterns. allomembers j–f have a sigmoidal prismatic geometry, successively offlapping to the se. there is no evidence of thickening toward the orogen. in contrast, overlying allomembers e–a show progressive development of a depocentre along the western margin of the basin. the increasing accommodation rate on the updip coastal plain caused marine deltas to be starved of sediment, leading to progressive backstep of shorelines. simultaneously, alluvial deposits within the depocentre show an upward increase in the proportion of subaqueous to subaerial facies, culminating in the incursion of brackish and finally marine waters. thus tectonic subsidence rate had a first-order affect on both the volume of sediment available to build marine deltas and also on the local character of facies that accumulated on the coastal plain. the onset of flexural subsidence in allomember e appears to have resulted in subtle uplift of a forebulge, resulting in dramatic deflection of river systems. despite the clear tectonic signature, successive transgressions and regressions involved similar horizontal displacements of the shoreline, regardless of subsidence rate. this suggests that modest eustatic changes also influenced the accommodation available. based on the measured horizontal excursions of the shoreline, the vertical thickness of alluvial strata, and realistic alluvial gradients, an average eustatic excursion of about 24 m is calculated. the incision of valley systems is attributed in part to periods of eustatic fall. however, valleys seem too long to be explained by eustasy alone, and hence secular changes in discharge are postulated as an additional forcing factor. climatic cycles in the milankovitch band may have been responsible for both eustatic and discharge variations. 40 geologia croatica 56/1 this paper is concerned with the dunvegan formation, which is an early to mid-cenomanian deltaic unit. this 90–270 m thick clastic wedge was deposited on the western margin of the western interior seaway (fig. 1), during a period of generally rapid subsidence of the north american plate resulting from dynamic and static loading mechanisms due to subduction and crustal shortening (mitrovica et al., 1989). at least 400 km of nw to se delta progradation can be demonstrated within the study area, which took place over about 2 my. the dunvegan fm. is extensively exposed in thrust sheets for several hundred km along the nw–se trending rocky mountain foothills, and also for 300 km in undeformed strata exposed in an e–w transect along the peace river valley (fig. 1). over a study area of about 80,000 km2, the stratigraphy of the dunvegan fm. was delineated using 2340 well logs and 60 major outcrop sections (plint, 2000; fig. 2). 1.1. aim of this paper this paper summarizes the main results from previous studies concerned with various aspects of the dunvegan formation (plint, 1996, 2000, 2002; plint et al., 2001; mccarthy & plint, 1998, 1999, in review; mccarthy et al., 1999; mccarthy, 2002; lumsdon & plint, 2003 – in press; plint & wadsworth, in review). the analysis of the depositional history of the dunvegan has involved several main steps. 1) development of a robust allostratigraphy based on marine transgressive surfaces. this allows lateral facies relationships to be determined, and also permits isopach maps to be constructed. it is assumed that the bounding surfaces of allostratigraphic units approximate time lines. unfortunately, there is no means available to determine absolute ages for the bounding surfaces. fig. 1 inset maps show location of study area in western canada, and cenomanian palaeogeography of the dunvegan formation within the western interior seaway. the line of section shows the location of the dip section shown schematically in fig. 3, and drawn to scale in fig. 23 (from plint & wadsworth, in review). 2) construction of palaeogeographic maps for each allomember showing maximum marine transgressive and regressive limits. this provides a picture of the regional shoreline trends and also permits quantification of horizontal movements of the shoreline. 3) construction of isopach maps for each allomember. these show the geometry of the accommodation available for each allomember. because each allomember aggraded essentially to sea level, isopach patterns can be interpreted in terms of subsidence patterns. 4) the analysis of sedimentary facies within a palaeogeographic and accommodation framework allows vertical and lateral facies changes to be interpreted in terms of proximity to the shoreline and to spatial variation in accommodation rate. 5) mapping of palaeo-valley systems in both subsurface and outcrop. the resulting maps reveal the influence of various tectonic features (faults, forebulge) on drainage systems. 6) analysis of palaeosols mantling interfluve surfaces between valley systems. this reveals both vertical and lateral variations in the character and evolution of palaeosols that reflect palaeodrainage conditions and rates of clastic flux related to distance from the margins of valleys. 41plint: clastic sediment partitioning in a cretaceous delta system, western canada... fig. 2 map of study area showing stratigraphic data base, including location of 2340 well logs and principal outcrop sections in the foothills and peace river valley (from plint, 2000). 42 geologia croatica 56/1 7) sequence stratigraphic interpretation, including definition of systems tracts on the basis of facies associations, stratal lap-out patterns, palaeogeography and palaeogeomorphology. the main aim is to interpret the principal controls (tectonic, eustatic, climate) on changing patterns of deposition and erosion, utilizing elements 1–6 above. 1.2. collaboration this paper presents a compilation of results from the research of the author on the regional stratigraphy and sedimentology of the dunvegan fm. however, very significant contributions to this understanding have been made by my post-doctoral fellows and graduate students whom i wish to acknowledge here. dr. jennifer wadsworth investigated the sedimentology of the valley-fill deposits exposed along the peace river, was the first to recognize tidal features, and made preliminary maps of their subsurface distribution. dr. paul mccarthy undertook palaeopedological investigations of the interfluve surfaces between the valleys, and confirmed the existence of major hiatal surfaces. bira faccini spent part of his phd project investigating the sedimentology and stratigraphy of the dunvegan strata in the valley of the kiskatinaw river, and documented the vertical changes in alluvial facies in response to changes in accommodation rate. matthew lumsdon conducted detailed facies analysis of alluvial strata near the orogenic margin of the basin and showed how drainage conditions and facies successions on the alluvial plain were strongly linked to regional subsidence rates and patterns. the work of these colleagues is indicated at appropriate points by references to our publications. 2. regional geological setting during the cretaceous, north america was progressively flooded from the south by warm saline waters of the ancestral gulf of mexico – tethys, and from the north by cooler, less saline water of the boreal ocean. these marine embayments merged just before the albian–cenomanian boundary (96 ma) to form the western interior seaway, which continued to widen until mid-turonian time (90 ma) (williams & stelck, 1975; kauffman & caldwell, 1993; hay et al., 1993; fig. 1, inset). static and dynamic loading of the lithosphere above the subducting farallon plate produced a wide sedimentary basin comprising two main parts. static loading by the orogenic wedge generated a relatively narrow (< 300 km), rapidly-subsiding flexural foredeep, to the east of which lay a broader region, 1000–1500 km wide, of moderate subsidence that reflected dynamic loading by large-scale mantle flow (mitrovica et al., 1989; pang & nummedal, 1995; catuneanu et al., 1997). thus, the interior seaway can be attributed, in part, to static and dynamic loading of the north american plate. however, eustatic rise, broadly ascribed to accelerated plate spreading rates (kauffman & caldwell, 1993), was also a factor with turonian sea level estimated to have peaked at 180 m (sahagian & jones, 1993) to 300 m (mcdonough & cross, 1991), above present level. relative sea level rise at the albian–cenomanian boundary led to widespread deposition of marine shales, marking the onset of the greenhorn cycle (kauffman & caldwell, 1993). in alberta and british columbia, this transgressive phase was accompanied by rapid flexural subsidence, recorded by a westwardthickening wedge of laminated, organic-rich marine shale of the shaftesbury formation (equivalent to the hasler, goodrich and cruiser formations in the nw part of the basin in british columbia; stott, 1982; fig. 3). the shaftesbury formation coarsens upward into deltaic strata of the early to middle cenomanian dunvegan formation which represents a major progradation of the shoreline. however, unlike the fluviodeltaic mountain park fm. strata below the shaftesbury formation, which prograded towards the north and nw, progradation of the dunvegan fm. was in the opposite direction, towards the se, parallel to the cordillera (fig. 3). this change in regional sediment dispersal direction probably records the northward migration of the centre of maximum cordilleran uplift as a result of the lateral migration of accreted terranes along the continental margin during the cretaceous (eisbacher, 1981; poulton, 1994). the principal source of sediment for the dunvegan formation is considered to have lain in northern british columbia and southern yukon, where the formation is dominated by alluvial sandstones and conglomerates (stott, 1982). palaeocurrent observations (plint, unpubl. data) and mapping of valley systems and shorelines (plint, 1996, 2000, 2002; plint & wadsworth, in review) show that the principal fluvial palaeoflow direction was toward the se, although several subordinate sources of sediment were scattered along the cordilleran margin of the basin further to the south. isopach maps of successive allomembers of the dunvegan fm. (discussed in more detail below), show that flexural subsidence of the foredeep was minimal during deposition of the older five allomembers, j–f, each of which constitute broadly prismatic packages of sediment that show no significant thickening towards the orogen. in contrast, the younger five allomembers, e–a show major thickening towards the orogen, indicating the onset of renewed subsidence during and following allomember e time (plint et al., 2001, lumsdon & plint, 2003 – in press). this phase of subsidence led to major backstep of the dunvegan delta complex in allomember a time as accommodation rate gradually exceeded sedimentation rate, culminating in widespread marine transgression at the base of the overlying kaskapau fm. (fig. 3). 43plint: clastic sediment partitioning in a cretaceous delta system, western canada... 3. stratigraphy 3.1. lithostratigraphy the dunvegan formation ranges from 90–270 m thick and crops out extensively on thrust sheets in the alberta and british columbia foothills, and also in the peace river valley, where undeformed strata are exposed in the vicinity of fort st. john, and extend for over 300 km to the east (stott, 1982; fig. 2). the dunvegan formation comprises a succession of alluvial and shallow marine sandstones, siltstones and shales that separate underlying marine shales of the shaftesbury formation from overlying marine shales and minor sandstones of the kaskapau formation (fig. 3). it has long been recognised that the dunvegan formation has an interfingering, diachronous relationship with the underlying shaftesbury, and overlying kaskapau formations (stelck & wall, 1955; stelck et al., 1958; alberta society of petroleum geologists, 1960; singh, 1983), and the boundaries of the dunvegan formation are placed at the first and last appearance of sandstone in an otherwise shale-dominated succession. for mapping purposes, this definition serves well. however, in order to analyze in more detail the depositional history and palaeogeography of the shaftesbury, dunvegan and kaskapau formations, it is useful to subdivide the rocks into smaller, geneticallyrelated packages on the basis of mappable surfaces. such an allostratigraphic approach was introduced by bhattacharya (1989). 3.2. allostratigraphy allostratigraphy involves the subdivision of the stratigraphic record into packages “defined and identified on the basis of their bounding discontinuities” (north american commission on stratigraphic nomenclature, 1983). bounding discontinuities can take several forms, including subaerial erosion surfaces, the upper surfaces of palaeosols, erosional marine ravinement surfaces, and weakly-erosional to non-erosional marine flooding surfaces (fig. 4). in a subsurface study, bhattacharya (1989) demonstrated that the dunvegan formation could be subdivided into seven transgressive–regressive packages, bounded by regional marine flooding surfaces. the seven packages, or allomembers, were designated g to a in ascending order, and each was shown to consist of several component, sandier-upward successions, termed ‘shingles’ (broadly equivalent to parasequences; bhattacharya, 1989; bhattacharya & walker, 1991a). analysis of facies successions in core led bhattacharya & walker (1991b) to interpret the dunvegan formation in terms of a series of prograding and aggrading delta complexes. because of their regional extent, allomembers were interpreted to record an allogenic, tectonic control on subsidence rate. fig. 3 schematic nw–se dip section showing the dunvegan fm., the stratigraphic terminology applied to the underand overlying units, and the stratigraphic range of important zone fossils. the boundaries of the lithostratigraphic dunvegan fm., and the allostratigraphic dunvegan alloformation are also indicated. the former is very diachronous (from plint et al., 2001). 44 geologia croatica 56/1 in contrast, the more localised distribution of individual shingles suggested an autogenic origin, controlled by delta distributary switching (bhattacharya & walker, 1991a). plint (1996, 2000) extended the allostratigraphic scheme of bhattacharya & walker (1991a), tracing the dunvegan northward from township 67 to correlate with outcrop sections on the peace and beatton rivers. an additional three allomembers, j–h were added to the original scheme of bhattacharya (1989), and it is likely that further north, yet more allomembers could be defined, but which downlap and pinch out before reaching the study area. 3.3. recognition of depositional sequences it can be shown that the marine ravinement and flooding surfaces that define allomembers in more downdip areas can be traced updip into surfaces bounding well-developed interfluve palaeosols (mccarthy & plint, 1998; mccarthy et al., 1999; plint et al., 2001). these palaeosol-bounding surfaces can in turn be traced into erosional surfaces that define a network of valleys incised into the upper surfaces of most of the dunvegan allomembers (fig. 4). therefore, each component allomember of the dunvegan formation preserves evidence for relative sea level rise, expressed by sandstones filling valleys, by the abrupt juxtaposition of offshore marine or lagoonal mudstone above sandier, shallower-water deposits separated by a flooding or ravinement surface, and by changes in fluvial style in coastal plain areas (mccarthy et al., 1999). evidence for relative sea level fall and fluvial incision is provided by extensive valley systems (plint, 2002; plint & wadsworth, in review), interfluve palaeosols (mccarthy et al., 1999), and, in shallow marine areas, by erosive-based delta-front sandstones (plint, 1988, 1996; plint & nummedal, 2000). of the ten dunvegan allomembers studied, only allomembers j and e show a distinct downward shift of facies and onlap in the delta front area, as is required for the definition of a classical exxon type 1 sequence (van wagoner et al., 1988). the remaining allomembers show well-developed offlap to subtle onlap of fig. 4 diagram showing how allomembers and depositional sequences are defined. allomembers are bounded by regional marine transgressive surfaces (heavy dashed lines) and their lacustrine equivalents on the coastal plain. valley fills are included with the underlying allomember. depositional sequences are bounded on the coastal plain by a subaerial unconformity that defines valleys and interfluves. in downdip areas, this surface continues as the upper surface of the offlapping, falling stage systems tract (which may be a palaeosol, or a ravinement surface), and, basinward of the shoreline, as the correlative conformity. this surface is onlapped by valleyfilling and marine deposits of the lowstand and transgressive systems tracts. recognition of the four marine systems tracts relies heavily on regional mapping of shingle stacking patterns (from plint et al., 2001). 45plint: clastic sediment partitioning in a cretaceous delta system, western canada... parasequences in the delta front area and represent both falling stage and lowstand systems tracts, sensu plint & nummedal (2000), and plint et al. (2001). 4. sedimentary environments and facies the dunvegan fm. can be subdivided into three main depositional environments: prodelta, delta-front and coastal plain (including valley-fills). the main sedimentary characteristics of each of these environments are summarized below. 4.1. prodelta prodelta deposits consist mainly of cm to mm-bedded dark grey siltstones and mudstones. interbedded very fine sandstones are mm to cm thick and become thicker and more abundant upward (fig. 5). thicker sandstone interbeds are parallel-laminated or show wave or combined-flow ripples. rare, cmto dm-scale gutter casts may be present on the base of sandstone beds. in the more offshore facies, gutter casts are oriented parallel to shore, but in more nearshore deposits, they rotate to shore-perpendicular. bioturbation is generally sparse, and includes chondrites, planolites, teichichnus, and zoophycos. these sediments are organized in 5–20 m thick, sandier-upward successions interpreted to record progradation of individual delta lobes (fig. 6). 4.2. delta-front delta-front deposits are dominantly fineto locally medium-grained sandstone and form units from 1 to about 10 m thick. the bases of sandstone bodies may be either gradational with underlying prodelta facies (fig. 7), or sharp and erosive, commonly with spectacular gutter casts (figs. 8, 9). swaley cross-stratification and parallel lamination typify fine sandstone whereas dm-scale trough crossbedding is present in the upper fineto lower medium-grained sandstones. the delta-front sandstone bodies are commonly capped by 1–2 m of planar-laminated to massive rooted sandstone interpreted as beach and backshore deposits. sharpbased delta front sandstones are widely-recognized throughout the formation and are interpreted to record shoreface progradation during relative sea level fall (i.e. during the falling stage systems tract; plint & nummedal, 2000). delta-front sandstones can be mapped in welllogs, and their maximum progradational extent in each allomember can be traced. for each allomember, shorelines face consistently towards the e to se and fig. 5 detail of prodelta facies consisting of cm-scale interbeds of very fine sandstone and mudstone. sandstone beds are sharpbased with small grooves and flutes, and upper surfaces are typically ornamented with combined-flow ripples. beatton river section 1; scale bar = 20 cm. fig. 6 three successions of prodelta storm beds grading up into thicker sandstones of the delta front. the main package of sandstone is 4 m thick and is capped by a coal. flood creek, alberta. 46 geologia croatica 56/1 can be traced continuously for several hundred km. the palaeogeographic maps of allomembers j to a (figs. 10–16) show that the delta shoreline was broadly cuspate to lobate, suggestive of moderate to strong wave reworking of individual delta lobes. large bulbous delta lobes up to 80 km wide and 100 km long are recognized in allomembers i, d, e, and f, and are interpreted as lowstand deltas deposited at the end of periods of slow relative sea level fall. fig. 7 stacked prodelta to delta-front facies successions. the middle succession is 4 m thick; sulphur river, alberta. fig. 8 delta front sandstone unit resting erosively on dark laminated prodelta mudstone. sandstone is 7 m thick and is sharply overlain by laminated dark marine mudstone; person for scale. railway cutting section, grande cache, alberta. fig. 9 detail of large canoe-shaped gutter casts on the base of the delta front sandstone shown in fig. 8. gutter cast is 80 cm. wide. railway cutting section, grande cache, alberta. 47plint: clastic sediment partitioning in a cretaceous delta system, western canada... 4.3. coastal plain coastal plain deposits dominate the nw portion of the delta complex and comprise a complex array of facies broadly representative of a generally poorly-drained environment, traversed by numerous non-migrating river channels that formed ribbon sandstones in a matrix of lacustrine, marsh and poorly-drained floodplain mudstone, interstratified with crevasse splay and thin lacustrine delta sandstones. the abundance of tracks shows that the area was inhabited by numerous dinosaurs, primarily hadrosaurs, but with ankylosaur, theropod, crocodilian, large avian and possibly pterosaur tracks also recognized (m. lockley, pers. comm., 1997; r. mccrea, pers. comm., 1999; scott, 2000). coastal plain facies have been grouped into three facies associations that form distinct nonmarine systems tracts (plint et al., 2001) that reflect differing sedimentation:accommodation ratios. the facies characteristics of each systems tract are discussed in more detail below. 4.3.1. channel-dominated, low-accommodation systems tract this systems tract consists of multi-storey, laterally-accreted meandering channel sandstones, typically 5–8 m thick, that were only deposited within valleys, the base of which forms the lower boundary of the systems tract. there is very little floodplain mudstone preserved within the valley-fills. within a valley-fill, mud-free, cross-bedded sandstone generally dominates the lower storeys, whereas the uppermost, and most complete storey is sometimes much more mud-rich, with well-developed heterolithic stratification (figs. 17, 18). this suggests that the latest stage of valley-filling may have taken place under tidally-influenced conditions (cf. shanley et al. 1992; smith, 1987; willis, 1997). the uppermost fig. 10 palaeogeographic and isopach map of dunvegan allomember j. heavy stippled line in this and figures 11–16 indicate the maximum progradational extent of the delta-front sandstone, mapped from gamma ray log signatures. note how isopach lines trend perpendicular to the orogen in this map and in figs. 11–14. this pattern is interpreted to reflect deposition at a time when the rate of flexural subsidence was negligible. contour interval in figures 10–16 = 10 m. 48 geologia croatica 56/1 1–5 m of the valley-fill is sometimes occupied by a sandier-upward succession, commonly highly bioturbated, interpreted to record final filling of the valley by a small bay-head delta (figs. 18, 19). the bioturbation suggests incursion of brackish water, and this is consistent with the progressive drowning of the valleys and updip migration of marine influence (cf. mclaurin & steel, 2000). the upper boundary of the systems tract is placed at the generally abrupt transition (an expansion surface of martinsen et al., 1999), to lacustrine-dominated facies, that record a major change in the accommodation/ supply ratio. the prevalence of multi-storey sandbodies and scarcity of preserved floodplain mudstone suggests that these deposits reflect a relatively low accommodation rate that permitted protracted reworking of alluvial deposits within the valley (cf. aslan & blum, 1999; martinsen et al., 1999). available evidence does not permit us to differentiate sediments deposited during regional base-level rise from possible terraces deposited during the falling stage (cf. blum & price, 1998). 4.3.2. lacustrine-dominated, high-accommodation systems tract this systems tract is characterized by widespread, well-laminated to poorly-laminated and carbonaceous mudstone and coal facies that represent a range of lake and wetland environments. these facies enclose, and are interstratified with ribbon channel sandbodies (fig. 20), crevasse splays and sandier-upward, lake-fill successions (fig. 21). palaeosols are generally poorly developed and hydromorphic in character (palaeosol types 1–3, fig. 8 of mccarthy et al., 1999). the base of this systems tract is defined in two ways. it may abruptly overlie multistorey channel sandstones filling valleys, where the facies transition records the abrupt expansion of deposition beyond the confines of the valfig. 11 palaeogeographic and isopach map of dunvegan allomember i. 49plint: clastic sediment partitioning in a cretaceous delta system, western canada... leys (cf. martinsen et al., 1999). the prevalence of lacustrine facies indicates that accommodation was generated faster than it could be filled, resulting in standing bodies of water (cf. hampson et al., 1999). alternatively, it may abruptly overlie a sharp, micro-erosional surface above a well-developed palaeosol that defines an interfluve surface (mccarthy et al., 1999). it is significant that bioturbated lacustrine deposits are consistently observed for a few metres, immediately above sequence-bounding interfluve palaeosols. further up section, bioturbation disappears until the next interfluve surface is crossed. this observation suggests that interfluves were initially flooded by brackish-water lagoons, with an attendant burrowing fauna. this interpretation is consistent with the observation (mccarthy & plint, 1998, in review) of barite crystals in mudstones immediately above the top h and top g interfluve surfaces. this mineral is known to precipitate in modern hydromorphic soils associated with saline groundwater (stoops & zavaleta, 1978) the lacustrine-dominated, high-accommodation systems tract is the principal component of the nonmarine portion of sequences. it is here emphasized that the maximum flooding interval which is stratigraphically equivalent to the time of maximum marine transgression, consistently lies within, and not at the top of the lacustrine-dominated systems tract. this observation suggests that, for a significant interval of time after maximum transgression, accommodation was generated faster than it could be filled. 4.3.3. palaeosol-dominated, low-accommodation systems tract this systems tract is dominated by blocky mudstones that represent moderatelyto well-developed palaeosols (palaeosol types 4–5, fig. 8 of mccarthy et al., 1999). commonly, several well-developed palaeosol profiles are found in close vertical juxtaposition. these palaeosols are generally interstratified with crevassesplay sandstones and thin units of lacustrine and wetland facies. the base of this systems tract is defined where laminated lacustrine mudstones pass upward, typically over 1–2 metres, into a succession consisting of relatively well-developed complex palaeosols that are welded together (mccarthy et al., 1999). the top of the palaeosol-dominated systems tract is defined by a fig. 12 palaeogeographic and isopach map of dunvegan allomember h (from plint et al., 2001). 50 geologia croatica 56/1 subaerial erosion surface marking an interfluve (mccarthy & plint, 1998; in review; mccarthy et al., 1999; mccarthy, 2002) that is expressed as a sharp, but commonly subtle stratigraphic discontinuity having a micro-erosional relief of centimeters to decimeters. this systems tract is interpreted to represent a floodplain environment in which autogenic processes continued to build and fill minor depositional topography, but where the overall rate of vertical aggradation gradually decreased to nil, permitting progressively more time for pedogenesis. the upper part of each sequencebounding palaeosol succession represents several tens of thousands of years of sediment starvation and in-situ polygenetic pedogenesis (sensu marriot & wright, 1993). these palaeosols represent a period of nil to negative accommodation during which pedogenic overprinting is recorded in the upper part of the interfluve palaeosol complex (mccarthy & plint, 1998; mccarthy et al., 1999; fig. 22). the significance and spatial variability of interfluve palaeosols is discussed in more detail below. 5. palaeovalley systems extensive valley systems exist at the tops of dunvegan allomembers h, g, f and e (fig. 23). valley-filling deposits are well-exposed along the peace river valley between the alberta–british columbia border and erin lodge, some 140 km downstream, and also on fig. 13 palaeogeographic and isopach map of dunvegan allomember g (from plint et al., 2001). 51plint: clastic sediment partitioning in a cretaceous delta system, western canada... the beatton and kiskatinaw rivers (fig. 1; plint, 2002). valley-filling sandstones up to 30 m thick are also present at the top of allomembers d, c and a. however, these younger sandbodies are typically < 1 km wide and are generally impossible to map in subsurface with the available well density: they will not be discussed further in this paper. up to 4800 wells and 40 outcrops were used to map valley systems incised into the top surfaces of allomembers h to e. individual valleys can confidently be mapped for distances of 110 km in allomember h, 250 km in allomember g, 200 km in allomember f, and 320 km in allomember e. valleys maintain a remarkably consistent depth over their entire length, with maximum depths ranging from 31–40 m, with an overall average of about 21 m. valley width varies from a few hundred metres to a maximum of about 8 km, with most valleys being about 1–2 km wide. cross-valley depth varies abruptly suggesting the development of a terraced morphology. limited core in downdip valley reaches and abundant outcrop in up-valley reaches permits five main facies to be identified. up-valley reaches are dominated by fine to medium grained, trough crossbedded sandstone. widely-distributed but uncommon tidal bundles defined by carbonaceous drapes, bundle sequences and sigmoidal cross-stratification are present up to 30 km landward of the marine transgressive limit, and indicate tidal backwater effects, probably under a microtidal regime. rippled and planar laminated sandstone is an accessory facies. locally-preserved lenses of rooted, fig. 14 palaeogeographic and isopach map of dunvegan allomember f (from plint et al., 2001). 52 geologia croatica 56/1 blocky to laminated mudstones and coals are interpreted to represent remnants of floodplain deposits preserved within the valleys. inclined heterolithic stratification on a dmto m-scale is common at the top of valley-fills up to 110 km landward of the marine transgressive limit; this facies probably records a complex interaction between tidal processes and ?seasonal river discharge fluctuations. down-valley reaches, typically within about 50 km of the lowstand shoreline, have a sandstone-dominated lower portion and a mudstonerich upper portion in which a variety of thinly-bedded heterolithic strata are encountered. heterolithic facies may be organized in sandier-upward successions that might represent upward-shallowing bay-head deltas, or muddier-upward successions that might represent tidal flats or muddy ihs filling a channel. ubiquitous sub-mm scale mud drapes and bidirectional ripple cross lamination provide strong evidence for tidal processes (fig. 19). soft-sediment deformation and micro-faulting are abundant and might reflect dewatering, slumping, earthquake shock and dinoturbation (plint & wadsworth, in review). within about 20–40 km of the maximum regressive shoreline, valleys in each allomember become unrecognizable, with the exception of one major channel in each of allomembers e and f, which obviously continues as a distributary that feeds a major lowstand delta lobe. the most seaward part of the delta plain lacking valleys fig. 15 palaeogeographic and isopach map of dunvegan allomember e. note the appearance of a semi-circular depocentre in the nw corner of the study area, interpreted to record the onset of renewed flexural subsidence (from plint et al., 2001). 53plint: clastic sediment partitioning in a cretaceous delta system, western canada... is interpreted as the lst, deposited when sea level was slowly rising and rivers started to backfill their valleys. valley filling took place primarily during the early tst. in downdip areas, the top of the valley fill is overlain, at a glossifungites transgressive surface, by a few dm of intensely bioturbated muddy sandstone that constitutes a very thin marine tst. further landward, a thin coal commonly separates the valley-fill from overlying marine deposits; the coal typically extends about 30 km seaward of the maximum marine transgressive limit and records the development of sediment-starved mires behind the transgressing shoreline (fig. 19). further landward, in areas not inundated by the sea, valley-fills are typically overlain by laminated lacustrine mudstones, thin coals or pedogenic mudstones. 6. interfluve palaeosols: spatial variability and palaeoclimatic significance the palaeosols that mantle interfluve surfaces are similar to modern alfisols and each example records (i) aggradation on an alluvial/coastal plain; (ii) a subsequent static and/or degradational phase related to valley incision, non-deposition and soil thickening; and (iii) a final aggradational phase related to valley-filling and renewed sedimentation across the coastal plain (mccarthy & plint, in review; fig. 22). within this overall template, however, variations in palaeosol thickness, redoximorphic features, illuvial clay content, and geochemistry suggest developmental control by hydrological characteristics that were influenced both by the nature of the underlying alluvial sediments, and fig. 16 composite map showing the maximum progradational shorelines of dunvegan allomembers d, c and a, and also isopachs for the entire d–a interval. note the prominent depocentre along the western margin of the study area, and progressive rotation of isopach lines from n–s to nw–se (from lumsdon & plint, 2003). 54 geologia croatica 56/1 55plint: clastic sediment partitioning in a cretaceous delta system, western canada... by distance from the dissected valley edge. palaeosols that developed closer (few hundred m to few km) to valley margins are thicker, have greater quantities of illuvial clay, and display characteristics suggestive of well-drained conditions relative to those palaeosols that developed further (> 5–10 km) from valley margins. variations in drainage and palaeotopography during landscape dissection resulted in different palaeosol development styles on interfluve surfaces that can be shown, on the basis of physical correlation, to have the same geomorphic age. renewed coastal plain aggradation and syndepositional pedogenesis is marked, at sites a few km from valleys, by an obvious increase in grain size, multiple organic horizons, sedimentary microlamination, and the presence of sphaerosiderite. these features suggest the resumption of periodic flooding of the coastal plain as fluvial channels once again migrated beyond the valley walls. the presence of barite coupled with elevated levels of ca, mg, sr, and p suggest that interfluve palaeosols adjacent to valley margins were initially flooded with brackish water (mccarthy & plint, 1998; driese et al., 1992). in contrast, an interfluve palaeosol located 15 km from the nearest valley is directly capped by a coal, indicating water-table rise, increased accommodation rate, but negligible clastic supply (fig. 22). the interfluve palaeosols contain abundant pedogenic clay minerals (interstratified illite–vermiculite) in the < 0.2 mm fraction that yield δ18o values of -12.9‰ to -11.6‰. these isotopic ratios are considered to record the composition of the cretaceous rainwater at this palaeo-latitude of about 65°n, and suggest soil temperatures in the range 9–16°c (vitali, et al., 2002). this temperature estimate is consistent with fig. 17 multi-storey valley-fill at beatton river, b.c. note how base of valley-fill cuts downward from right to left, eventually intersecting the top of a sheet-like delta-front sandstone. lower storeys are crossbedded sandstone but the uppermost storey shows well-developed inclined heterolithic stratification, possibly deposited under the influence of seasonal discharge fluctuations. maximum thickness of valley-fill = 23 m (from plint & wadsworth, in review). fig. 18 transverse section summarizing the main characteristics of valley-fills in an up-valley, fluvial-dominated reach (from plint & wadsworth, in review). 54 geologia croatica 56/1 55plint: clastic sediment partitioning in a cretaceous delta system, western canada... estimates based on pedological characteristics (mccarthy & plint, 1999) and on palaeobotanical information (7–13°c; upchurch & wolfe, 1993). 7. recognizing accommodation change evidence of accommodation changes, both positive and negative, can be inferred from various sedimentological and stratigraphic features of the dunvegan fm. seven main lines of evidence will be summarized: 1) marine transgressive surfaces; 2) isopach patterns; 3) distribution and character of nonmarine facies; 4) valley systems; 5) interfluve palaeosols; 6) sharp-based deltafront sandstones, and 7) palaeodrainage patterns. 7.1. regional marine transgressive surfaces regionally-mappable marine transgressive surfaces are among the most recognizable features of the dunvegan fm., allowing the formation to be divided into allomembers (fig. 23). importantly, the well log response that corresponds to these transgressive surfaces can be traced inland for up to about 150 km across the coastal plain that lay landward of the transgressive limit of the marine shoreline. tracing these non-marine (lacustrine) flooding surfaces allows the complete geometry of the allomember to be determined, including both the marine and non-marine portions. transgressive surfaces provide clear evidence of an increase in the accommodation : sedimentation ratio which led to shoreline transgression. comparison of maps in figs. 10–16 shows how the transgressive distance varied within and between each allomember. figure 24 summarizes the ‘average’ distance that the shoreline moved landward and seaward for each allomember. 7.2. regional isopach maps and accommodation changes figures 10–14 illustrate the regional palaeogeography and geometry of the lower 5 dunvegan allomembers, fig. 19 longitudinal section summarizing the main characteristics of valley-fills from the valley mouth to a point about 180 km up-valley (from plint & wadsworth, in review). fig. 20 example of lenticular fluvial sandstone (up to 8 m thick), interpreted to represent an anabranch of an anastomosed river, enclosed in grey pedogenic and lacustrine mudstones. coldstream creek, b.c. 56 geologia croatica 56/1 57plint: clastic sediment partitioning in a cretaceous delta system, western canada... j to f. allomembers j to f are markedly sigmoidal in profile, thinning updip onto the coastal plain, and also seaward through downlap onto the condensed section (fsu marker, fig. 23). the maps for allomembers j to f very clearly illustrate the progressive basinward (i.e. southeastward) shift of the depocenter. bathymetric deeps (i.e. water-filled space) remaining between delta lobes were filled by particularly thick intervals of the succeeding allomember. this pattern may reflect differential compaction over older lobes, leading to diversion of rivers into the intervening, topographically low areas (cf. blum & price, 1998). isopach lines in figs. 10– 14 are essentially parallel, and trend ne–sw, perpendicular to the orogen. the isopachs show no evidence of thickening towards the foothills deformed belt. this critical observation shows that during deposition of allomembers j to f, this part of the basin experienced essentially no differential tilting toward the orogen. figures 15 and 16 illustrate the palaeogeography and geometry of allomember e and allomembers d–a combined (because the bounding surfaces of allomembers d, c and b cannot be mapped across the entire study area). the isopach pattern for allomembers e to a shows a dramatic change relative to older allomembers. allomember e shows a pronounced updip thickening towards the nw with the development of an isopach ‘moat’ that extends about 70 km from the present deformation front. all of this semi-circular depocentre is filled with nonmarine deposits which reach 80 m in thickness in outcrop in the pine river – coldstream creek area (lumsdon & plint, 2003 – in press; fig. 2). in the se however, isopach patterns for allomember e resemble those of older allomembers in preserving the broad ne–sw trend, with the thickest parts of allomember e filling the bathymetric deep fronting allomember f. the semi-circular sedimentary ‘moat’, first recognized in the nw part of allomember e, expands in allomembers d–a to a radius of about 250 km, across which allomembers d–a thicken from about 30 to 100 m (fig. 16). note how isopach lines progressively rotate to parallel the orogen, reflecting the increasing importance of flexural subsidence towards the sw. the thickening of allomembers e to a in the nw corner of the study area is interpreted to record the onset of a new phase of flexural subsidence adjacent to the active margin of the basin (cf. rogers, 1998). the generation of new alluvial accommodation in the updip portion of the delta system had a pronounced affect on deposition in the marine realm downdip. allomembers j–e are relatively thick and the delta-front areas are relatively sand-rich. in contrast, the deltas in allomembers d–a (located in the se corner of the study area; fig. 16), are relatively thin and sand-starved. this is interpreted to reflect sediment partitioning between alluvial and marine depocentres, with the balance between the two progressively shifting in favour of the alluvial realm, as the orogen-proximal subsidence rate increased through allomembers e to a. 7.3. distribution and character of nonmarine facies in each allomember, only the lower 2–4 parasequences, which comprise the transgressive and highstand systems tracts, include both marine delta front / prodelta and correlative coastal plain deposits (fig. 25). younger parasequences offlap seaward and consist of only marine delta front / prodelta facies (plint et al., 2001). the offlapping deltaic parasequences are interpreted to have been deposited during the falling stage systems tract (plint & nummedal, 2000; plint et al., 2001). the top of the hst became a non-depositional surface during the fsst. during this time, rivers began to incise valleys, starting at the seaward margin of the highstand systems tract (plint, 2002). rivers incised progressively headward during the fsst, and also continued to erode valleys across the upper surface of the fsst as sea-level continued to fall. interfluves between valleys were starved of sediment for many tens of ky, during which time they developed thick and mature soil profiles (mccarthy et al., 1999, mccarthy & plint, in review). fig. 21 examples of stacked sandier-upward lake-fill successions typical of much of the dunvegan coastal plain. lynx creek, alberta; person for scale. 56 geologia croatica 56/1 57plint: clastic sediment partitioning in a cretaceous delta system, western canada... the restriction of coastal plain deposits to the tst and hst, which have an aggradational to progradational stacking pattern, show that alluvial accommodation was only generated during the rising half of the relative sea-level cycle. the fact that the alluvial deposits in allomembers i–f form a gradually updip-thinning sheet suggests that accommodation was generated by eustatic sea-level rise rather than by flexural subsidence. the fig. 22 diagram summarizing the developmental history of interfluve palaeosols, and also showing how the history and character of the palaeosol varies with distance from the margins of palaeovalleys. the distance from the valley margin strongly influenced the drainage of the interfluve, and also controlled the rate of sediment flux once the valley had been filled (from mccarthy & plint, in review). a b c incision ~ local soil succession depends on location, topography, parent material, vegetation, etc. moderately well-drained no truncation poorly drained no truncation . == =. c .-. ..,: . .....; transgressive highstand poorly-drained coastal plain with frequent flooding. sediment supply and accommodation rate are both high. cumulic pedocomplexes develop across the coastal plain. falling stage lowstand fluvial incision results in water-table drop near dissected valley edge. soil profile thickening, clay illuviation and erosion occur close to the valley margin . a high water table persists towards the centre of the interfluve. --"<'""--r~< 1 km --'''!''''-few km -~.,,!~.--:> 10 km ------i thick cumulic cap brackish influence cc co • blocky structure clay coatings mottles 1) root traces ~ siderite concretions sphaerosiderite fe-oxide nodules organic fragments transgressive after valley fills, renewed flooding occurs on interfluves, and water table rises. thick cumulic soils cap the truncated interfluve palaeosol near the valley margin whereas peat accumulates far from the source of clastic supply. a brackish influence is felt adjacent to valleys but groundwater remains fresh toward the centre of the interfluve. o horizon composed of organic soil material a mineral soil horizon mixed with humified organic material bw subsurface horizon with some colour or structure development 8 9 gleyed subsurface horizon (contains reduced iron) bt subsurface accumulation of silicate clay c mineral horizon relatively unaffected by pedogenic processes ac transitional horizon with some a and c properties bc transitional horizon with some band c properties 58 geologia croatica 56/1 59plint: clastic sediment partitioning in a cretaceous delta system, western canada... updip and westward thickening of alluvial deposits in allomembers e–a however, reveals an additional component of flexural subsidence along the basin margin. thus, the overall geometry of allomembers (‘sigmoidalprismatic’ in allomembers j–f, versus wedge-shaped in allomembers e–a) reveals a fundamental difference in the geometry of accommodation generation. for allomembers j–f, tectonic tilting was negligible and eustatic change appears to provide the simplest explanation for the parasequence stacking pattern and for the restriction of alluvial deposits to the rising half of the relative sea level cycle. in contrast, updip thickening of alluvial deposits in allomembers e–a records the onset of flexural subsidence which partially overprinted the effects of eustatic changes in the more distal (se) part of the basin. allomembers e to a contain semi-circular depocentres in the nw portion of the study area (figs. 15, 16). alluvial rocks filling those depocentres are wellexposed in ne british columbia. non-channelised alluvial facies represent lake, mouth-bar, levee and crevasse splay environments, and organic histosol (coal), poorlydrained, intermediate redox and better-drained palaeosols. siderite, organic debris and dinosaur tracks are fig. 23 summary dip section (located in fig. 1) drafted to scale, with the top of allomember a as a datum, showing the stratigraphic distribution of valley-fills. only valleys on allomembers h–e can be mapped with the available well density (from plint & wadsworth, in review). fig. 24 scale drawing summarizing the average shoreline displacement for each transgressive–regressive cycle of the dunvegan fm. note the similarity in shoreline displacement for allomembers i–c. only the transgressions at the tops of allomembers c and a show a transgressive distance that greatly exceeds the regressive distance, probably reflecting an accelerating subsidence rate and increasing accommodation:sedimentation ratio (see also fig. 16). 58 g eologia c roatica 56/1 59 p lint: c lastic s edim ent p artitioning in a c retaceous d elta s ystem , w estern c anada... ubiquitous elem ents of these facies. c hannelized facies are dom inated by non-m igrating (probably anastom osed) sandstone channel-fills (lu m sd o n & plin t, in press). the non channelized facies form tw o associations w hich are interpreted on the basis of intrinsic facies characteristics, to represent different accom m odation rates. a ssociation a is dom inated by crevasse splays, fig. 25 d ip section, draw n to scale and datum ed on the dow nlap surface, show ing (below ) the organization of parasequences w ithin allom em bers h –d . the upper diagram is a chronostratigraphic representation of the low er cross-section, based on the assum ption that each parasequence represents an equal interval of tim e. the chart em phasizes the depositional hiatus on the upper coastal plain that develops during the falling stage and low stand system s tracts (from p lin t et al., 2001). o section flattened on regional downlop surface ~=---~6 4 :3 ~ ~ 10 9 m ,,~., "u~·"u ; " coaslal plain 2:(0 della front sandstone _ _ prodeila mudstone ~ sequence bounding paleosol eroded sediments istratigraphic cross-sectk5n] e --+ ~ g o d' ill i 60 geologia croatica 56/1 61plint: clastic sediment partitioning in a cretaceous delta system, western canada... levees, intermediate redox and better-drained palaeosols. association b is dominated by lakes, mouth-bars, organic and poorly-drained palaeosols. association a, indicating relatively well-drained conditions, dominates allomembers g to the lower part of e. from near the middle to near the top, allomember e is progressively dominated by association b, but the uppermost 5 m shows an abrupt return to better-drained palaeosols (fig. 26). allomembers d to a show alternations between associations a and b, although overall, association b predominates upward. the basal units of the overlying kaskapau fm. comprise a 40–50 m thick transitional succession dominated by facies of association b, but also including brackish-water lagoonal deposits, overlain by marine deposits (fig. 26). when the vertical changes in alluvial facies associations are considered in the context of the geometry of their host allomembers, the relationship between facies and accommodation rate becomes clear. allomembers h to f thin towards the nw suggesting minimal accommodation in that direction, and this is reflected in their constituent alluvial facies (association a), which are dominated by relatively well-drained environments. the upward change within allomember e, from association a to relatively poorly-drained association b is interpreted to record an upward increase in accommodation rate. this change is independently suggested by the isopach ‘moat’ in allomember e, attributed to renewed flexural subsidence (figs. 15, 26). a 5 m thick pedocomplex at the top of allomember e suggests a final phase of very low accommodation rate. allomembers d–a are again dominated by poorly-drained freshwater environments, which pass upward into rocks of the basal kaskapau fm. which show progressively increasing marine influence. this facies succession reflects an increasing accommodation rate, which is also suggested by regional isopach patterns (fig. 16). 7.4. valley systems valley systems can be mapped for up to 320 km, and certainly extend to the nw beyond the study area (plint, 2002; plint & wadsworth, in review). representative maps of valley systems on allomembers f and e are shown in figs. 27 & 28. a crucial observation is that, at least over the study area, valleys show no systematic change in depth with distance upvalley. the considerable length, modest depth (average 21 m) and lack of longitudinal shallowing suggests that the valleys might reflect both eustatic and discharge-related forcing mechanisms. the incision of valleys into offlapping deltaic deposits suggests that there was some relationfig. 26 summary stratigraphic section oriented e–w across the northern part of the study area (fig. 1) showing, to scale, the thickness variations of the dunvegan allomembers. flexural subsidence was negligible in allomembers j–f, but became increasingly rapid in allomembers e–a as shown by the great expansion of the section towards the west. the increased accommodation rate is reflected in the vertical changes in alluvial facies in outcrop, with an overall upward increase in the proportion of waterlogged and subaqueous facies (association b) relative to better-drained facies (association a; from lumsdon & plint, 2003). 60 geologia croatica 56/1 61plint: clastic sediment partitioning in a cretaceous delta system, western canada... ship to relative sea-level fall which triggered erosion, starting at the offlap break fronting the hst. however, valleys seem ‘too long’ for the depth of incision, and the lack of headward shallowing suggests that an additional mechanism operated from upstream to effect incision. it is possible that cyclical changes in the ratio of sediment load to discharge might have been responsible for river incision far upstream (plint, 2002). it is not unlikely that changes in river discharge and small eustatic changes were both linked to global climatic oscillations in the milankovitch band, and in combination, were responsible for most of the changes in accommodation pattern. intermittently-active flexural subsidence was the third recognizable influence on the system. 7.5. interfluve palaeosols interfluve palaeosols are recognized on the basis of abundant clay coatings, fe oxide nodules and mottles which indicate the presence of bt horizons. the prolonged stability of these surfaces is also indicated by the fragmentation, ageing and assimilation of clay coatings, the intense biological reworking of the matrix, concentration of residual zr and tio2, and increased kaolinite content. minor erosion of the interfluve surface is suggested by the presence in the palaeosols of papules, pedorelicts and embedded grain argillans, all indicative of minor remobilization of the palaeosol. the sharp irregular upper boundary of the palaeosol fig. 27 palaeogeographic map of allomember f showing the maximum progradational limit of the marine shoreline, the boundary between aggradational (hst) and offlapping (fsst) parasequences, the distribution of valleys, and the maximum transgressive limit of the succeeding allomember e shoreline (from plint & wadsworth, in review). 62 geologia croatica 56/1 63plint: clastic sediment partitioning in a cretaceous delta system, western canada... (i.e. the sequence boundary) also indicates subtle erosion (mccarthy et al., 1999). immediately above the sequence boundary, the sediment tends to be welllaminated and grain size increases, containing abundant silt and very fine sand. this indicates renewed supply of sediment to the surface and low levels of physical reworking. the presence of abundant, partially-oxidized siderite and multiple surface organic layers indicates increased water-logging and flooding in response to a rising, but fluctuating water table. the stratigraphic position and vertical spacing of these very distinctive palaeosols is predictable to within 1–2 m on the basis of the projection of sequence boundaries from nearby well logs. this gives us confidence in our interpretation of sequence-bounding unconformities on the basis of well log correlations. the characteristics of the interfluve palaeosols indicate very significant depositional hiati, of the order of tens of ky, which corroborates the evidence provided by valleys for lengthy periods of negative accommodation across the coastal plain. 7.6. sharp-based delta-front sandstones progradation of a delta typically produces a succession in which prodelta mudstone grades up into interbedded sandstone and mudstone and finally clean delta front sandstone. this walthurian succession of facies indicates a gradual change in environmental conditions from deeper to shallower. in contrast to this ‘norm’, erosive-based delta front sandstones are widespread in the dunvegan fm. swaley cross-stratified or cross-bedded fig. 28 palaeogeographic map of allomember e showing the maximum progradational limit of the marine shoreline, the boundary between aggradational (hst) and offlapping (fsst) parasequences, the distribution of valleys, and the maximum transgressive limit of the succeeding allomember d shoreline (from plint & wadsworth, in review). 62 geologia croatica 56/1 63plint: clastic sediment partitioning in a cretaceous delta system, western canada... sandstone of the delta-front rests sharply on laminated mudstone or siltstone of the prodelta (fig. 8). the contact is generally ornamented with large gutter-casts oriented shore-normal. this succession implies removal of accommodation causing shallow water processes to impinge directly on a muddy, low-energy prodelta sea floor. eustatic fall or tectonic uplift seem to provide the only reasonable explanation for this facies succession (plint, 1988, 1996; plint & nummedal, 2000). it cannot be satisfactorily explained simply by changes in sedimentation rate. isopach maps provide no evidence for regional tilting, particularly in allomembers j–f, and therefore it is difficult to attribute accommodation loss and relative sea level fall to flexural uplift. in view of this geometric constraint, the pronounced offlap of deltaic parasequences has been attributed to eustatic fall (plint et al., 2001). one consequence of eustatic fall would be accommodation loss at the shoreline, resulting in the development of sharp-based delta-front sandstones. 7.7. palaeodrainage patterns observations and computer simulations (garciacastellanos, 2002) reveals two consistent and characteristic features of the drainage system in foreland basins. smaller tributary streams drain perpendicular to the orogen but merge into a large river that flows parallel to the orogen. secondly, the large axial river lies on the orogen-distal side of the basin, close to the forebulge. this pattern is exemplified by the new guinea foreland basin (fig. 29) in which the tributaries of the two main rivers, the fly and digul flow perpendicular to the orogen before turning abruptly to east and west, draining into the gulf of papua, and the arafura sea respectively. in the south a low but distinct drainage divide is revealed by the small rivers that traverse the southern margin of the island (fig. 29) and it seems likely that this divide marks the crest of the forebulge. the interpreted forebulge lies 250–300 km from the deformation front in the new guinea highlands; this distance is consistent with the flexural wavelength of the lithosphere, and with observations in other foreland basins. drilling data are sufficiently dense that the course of the dunvegan palaeovalleys can be reconstructed with some confidence. valleys on allomembers h, g and f have a broadly rectilinear pattern that is interpreted to reflect control of the precursor rivers by faults in the palaeozoic basement. a large se-prograding lowstand delta is evident in allomember f (fig. 27). overall, valleys are oriented perpendicular to the coast. the valleys on allomember e show a different pattern (fig. 28) in which all the tributary valleys flowing from the w and sw merge eastward into a single trunk valley that flows se, parallel to the coast for over 150 km before terminating in a large lowstand delta lobe. this pattern bears a remarkable similarity to that of the digul and fly rivers in new guinea. it is postulated that a subtle forebulge deflected the main valley on allomember e from a shore-perpendicular to a shore-parallel trend. the drainage pattern and main tectonic elements of new guinea and of allomember e are compared, at the same scale, in fig. 30. valleys on allomembers h to f are not deflected shore-parallel. this might be evidence that a forebulge was not a significant topographic element on the coastal plain. this in turn might reflect a phase of negligible flexural deformation, which is also indicated by the isopach maps. in contrast, the dramatic shore-parallel re-orientation of valleys in allomember fig. 29 map of rivers in the central portion of the new guinea foreland basin. the distinct drainage divide close to the southern coast is interpreted to reflect the position of the forebulge. note how the fly and digul river systems flow initially perpendicular to the fold and thrust belt, but distally, are diverted by and flow parallel to the forebulge. 64 geologia croatica 56/1 65plint: clastic sediment partitioning in a cretaceous delta system, western canada... e suggests that rivers were at this time influenced by a forebulge. it may be no coincidence that the apparent uplift of a forebulge is linked to the onset of renewed flexural subsidence, as revealed by the isopach maps of allomembers e and a–d. 7.8. quantification of eustatic change isopach maps (figs. 10–14) show that in allomembers j–f, flexural subsidence was unimportant. nevertheless, transgressions and regressions, and the cutting and filling of valleys continued to occur. because the geographic limits of transgressive and regressive shorelines, and the seaward limits of valleys can be mapped with some accuracy, it is possible to determine the horizontal extent of transgressive and regressive events in each allomember. by applying geologically realistic gradients to the surfaces over which the shoreline migrated, and including the thickness of verticallyaccreted coastal plain deposits, it is possible to make some first-order estimation of the vertical change of sea-level. this approach is summarized in fig. 31. the maximum transgressive limit of marine shorelines commonly lies within 10–20 km of the previous hst/fsst offlap break, and rarely inundates the hst coastal plain to landward. this implies a consistent balance between accommodation and sediment supply for each t/r cycle. the width and inferred slope of the fsst (60 km x 1:2:500) implies a slope height of about 24 m (fig. 31). an additional average of 11 m of coastal plain sediment accumulated during the tst and hst, suggesting a minimum vertical accommodation of about 35 m. calculation of water and sediment loads on the basis of simple airy isostasy suggests that a eustatic rise of about 24 m would result, after sedimentation to sea level, in about 35 m of vertical accommodation (plint & wadsworth, in review). this estimate of eustatic change does not take account of the elastic strength of the lithosphere which would tend to decrease the amount of subsidence for any given sediment and water load. it is therefore probable that eustatic excursions were somewhat less than 24 m. it is perhaps no coincidence that the average depth of valleys (21 m) is close to the eustatic change inferred on geometric criteria. modest eustatic fall at the coastline drove fsst delta progradation and also probably effected river incision across the hst and older fsst surfaces. however, the small (<24 m ) and slow (?50–100 ky) eustatic change that is indicated by this analysis seems unlikely to have been capable of driving valley incision for >300 km upstream, as is observed (plint & wadsworth, in review). we are led to infer an additional, upstream forcing mechanism, perhaps linked to changes in discharge:sediment load ratio, controlled by climatic cycles in the milankovitch-band. 8. conclusions a regional stratigraphy based on marine transgressive surfaces and approximately equivalent subaerial interfluve surfaces allows the deltaic dunvegan formation to be subdivided into ten transgressive–regressive allomembers with an average duration of <200 ky. allomembers prove to be practical and robust stratigraphic units, well-suited to a data-set that consists mostly of well logs. more sophisticated interpretation of changing accommodation patterns is based on analysis of the stacking pattern of component parasequences within allomembers. this approach allows transgressive and highstand systems tracts to be recognized. these contain fig. 30 maps comparing the pattern, scale and palaeogeographic relationships of the modern fly river (flipped and rotated) so as to mimic the orientation of the valley system in dunvegan allomember e. 64 geologia croatica 56/1 65plint: clastic sediment partitioning in a cretaceous delta system, western canada... both marine and aggradational coastal plain deposits. offlapping deltaic parasequences that lack an updip alluvial component are assigned to the falling stage systems tract. aggradational to onlapping parasequences at the seaward limit of the allomember are assigned to the lowstand systems tract. the seaward termini of valleys are considered to mark the geographic boundary between fsst and lst. valley systems that are typically 1–2 km wide, average 21 m deep, and > 320 km long are incised into the top surfaces of most allomembers; valleys have been mapped in detail for allomembers h to e. valleys are back-filled with muddy heterolithic tidal facies within a few tens of km of the valley mouth. further updip, fluvial processes dominated, producing multi-storey sandstone-dominated channel-fills. a weak tidal influence is inferred locally, and the effects of semi-diurnal tides extended about 30 km inland from the marine shoreline. major palaeosols mantle interfluves. a wide range of pedological features in the interfluve palaeosols indicate a protracted hiatus with extensive physical, chemical and biological modification of the parent material. the drainage of interfluve palaeosols progressively deteriorated with increasing distance from valley margins. allomembers can be grouped on the basis of isopach patterns. allomembers j–f have a sigmoidal prismatic geometry, successively offlapping to the se. there is no evidence of thickening toward the orogen. in contrast, allomembers e–a show progressive development of a depocentre along the western margin of the basin, presumably in response to renewed flexural subsidence. the increasing accommodation rate on the coastal plain had a profound effect on marine deltas further downdip, which were starved of sediment, leading to progressive backstep of shorelines. simultaneously, alluvial deposits within the depocentre show an upward increase in the proportion of subaqueous to subaerial facies, culminating in the incursion of brackish and finally marine waters. thus tectonic subsidence rate had a first-order affect on both the volume of sediment available to build marine deltas and also on the local character of facies that accumulated on the coastal plain. renewed flexural subsidence appears to have resulted in subtle uplift of a forebulge, resulting in dramatic deflection of river systems in allomember e, and also probably in allomember d. despite the clear tectonic signature, transgressions and regressions of the shoreline took place over similar fig. 31 block diagram summarizing the stratigraphic, geographic and topographic relationships between valleys and various systems tracts of a delta complex. strata assigned to the tst and hst include aggradational coastal plain deposits. offlapping deltaic strata of the fsst lack coeval coastal plain deposits and prograde an average of 60 km during slow relative sea level fall. fluvial incision is inferred to have occurred during this time, and was accompanied by development of very mature interfluve palaeosols. valley systems generally terminate about 35 km from the maximum progradtional limit of the delta front, and this limit is interpreted to indicate the fsst/lst boundary. aggradational and onlapping lst strata average 35 km wide, but include major lowstand deltas constructed at the termini of valley systems. on the basis of the assumed slopes and measured geographic dimensions, it is possible to infer cyclic eustatic changes of about 24 m (see text for discussion) (from plint & wadsworth, in review). 66 geologia croatica 56/1 67plint: clastic sediment partitioning in a cretaceous delta system, western canada... distances, regardless of whether subsidence was negligible (allomembers j–f) or accelerating (allomembers e–a). this suggests that modest eustatic changes also influenced the accommodation rate. on the basis of the measured horizontal excursions of the shoreline, the vertical thickness of alluvial strata, and realistic alluvial gradients, an average eustatic excursion of about 24 m is calculated. the incision of valley systems is attributed in part to periods of eustatic fall. however, valleys seem too long to be explained by eustasy alone, and hence secular changes in river discharge:sediment load ratio are postulated as an additional forcing factor. climatic cycles in the milankovitch band may have been responsible for both eustatic and discharge variations. acknowledgements the results presented here build on many years of field and subsurface work by the author, during which the regional stratigraphy of the dunvegan was established. he is grateful to joyia chakungal, steve donaldson, patrick elliott, bira faccini, yuanxian hu, sid leggett, matthew lumsdon, dany martinioni, paul mccarthy, chantale mcintosh, jennifer mckay, joanna moore, annemarie plint, jessica rylaarsdam, david uličny and jennifer wadsworth for cheerful and energetic assistance in the field over 18 seasons. i thank the natural sciences and engineering research council of canada for long-term support of our research through operating grants, and through the lithoprobe project; and also canadian hunter exploration, home oil, pan canadian petroleum, union pacific resources, wascana energy and petro–canada (all but the last of which have been consumed by corporate take-overs!), for their generous support of our research on the dunvegan formation. i am also grateful to margot mcmechan for her help with palinspastic restoration of foothills sections, don stott for guidance early in this study, and glen caldwell for insight into biostratigraphic problems. finally, i thank the organizing committee of the ias meeting in opatija for inviting me to contribute this review paper. 9. references alberta society of petroleum geologists (1960): lexicon of geologic names in the western canada sedimentary basin and arctic archipelago.– calgary, alberta, 380 p. aslan, a. & blum, m.d. (1999): contrasting styles of holocene avulsion, texas gulf coastal plain, usa.– in: smith, n.d. & rogers, j. (eds.): fluvial sedimentology vi. int. assoc. of sedimentol., spec. publ., 28, 193–209. bhattacharya, j.p. (1989): allostratigraphy and river and wave-dominated deltaic sediments of the upper cretaceous (cenomanian) dunvegan formation, alberta.– unpubl. phd thesis, mcmaster university, hamilton, ontario, 588 p. bhattacharya, j.p. & walker, r.g. (1991a): allostratigraphic subdivision of the upper cretaceous dunvegan, shaftesbury and kaskapau formations in the northwestern alberta subsurface.– bull. of canad. petrol. geol., 39, 145–164. bhattacharya, j.p. & walker, r.g. (1991b): river and wave-dominated depositional systems of the upper cretaceous dunvegan formation, northwestern alberta.– bull. of canad. petrol. geol., 39, 165–191. blum, m.d. & price, d.m. (1998): quaternary alluvial plain construction in response to glacio-eustatic and climatic controls, texas gulf coastal plain.– in: shanley, k.w. & mccabe, p.j. (eds.): relative role of eustasy, climate and tectonism in continental rocks. soc. of econ. paleont. and mineral., spec. publ., 59, 31–48. catuneanu, o., beaumont, c. & waschbusch, p. (1997): interplay of static loads and subduction dynamics in foreland basins: reciprocal stratigraphies and the “missing” peripheral bulge.– geology, 25, 1087–1090. driese, s.g., mora, c.i., cotter, e. & foreman, l.j. (1992): paleopedology and stable isotope chemistry of late silurian vertic paleosols, bloomsburg formation, central pennsylvania.– jour. of sed. petrol., 62, 825–841. eisbacher, g.h. (1981): late mesozoic–paleogene bowser basin molasse and cordilleran tectonics.– in: miall, a.d. (ed.): sedimentation and tectonics in alluvial basins. geol. assoc. of canada, spec. pap., 23, 125–151. garcia-castellanos, d. (2002): interplay between lithospheric flexure and river transport in foreland basins.– basin research, 14, 89–104. hampson, stollhofen, g.h. & flint, s. (1999): a sequence stratigraphic model for the lower coal measures (upper carboniferous) of the rhur district, northwest germany.– sedimentology, 46, 1199–1231. hay, w.w., eicher, d.l. & diner, r. (1993): physical oceanography and water masses in the cretaceous western interior seaway.– in: kauffman, e.g. & caldwell, w.e.g. (eds.): evolution of the western interior basin. geol. assoc. of canada, spec. pap., 39, 297–318. kauffman, e.g. & caldwell, w.e.g. (1993): the western interior basin in space and time.– in: kauffman, e.g. & caldwell, w.e.g. (eds.): evolution of the western interior basin. geol. assoc. of canada, spec. pap., 39, 1–30. lumsdon, m.p. & plint, a.g. (2003): changing alluvial style in response to changing accommodation rate in a proximal foreland basin setting: upper cretaceous dunvegan formation, ne british columbia, canada.– in: blum. m.d. & marriot, s.b. (eds.): fluvial sedimentology vii. int. assoc. of sedimentol., spec. publ., 35, in press. marriott, s.b. & wright, v.p. (1993): paleosols as indicators of geomorphic stability in two old red sandstone alluvial suites, south wales.– jour. of the geol. soc. london, 150, 1109–1120. martinsen, o.j., ryseth, a., helland-hansen, w., flesche, h., torkildsen, g. & idil, s. (1999): stratigraphic base level and fluvial architecture: ericson 66 geologia croatica 56/1 67plint: clastic sediment partitioning in a cretaceous delta system, western canada... sandstone (campanian), rock springs uplift, sw wyoming, usa.– sedimentology, 47, 235–259. mccarthy, p.j. (2002): micromorphology and development of interfluve palaeosols: a case study from the cenomanian dunvegan formation, ne british columbia, canada.– bull. of canad. petrol. geol., 50, 158–177. mccarthy, p.j. & plint, a.g. (1998): recognition of interfluve sequence boundaries: integrating paleopedology and sequence stratigraphy.– geology, 26, 387–390. mccarthy, p.j. & plint, a.g. (1999): floodplain palaeosols of the cenomanian dunvegan formation, alberta and british columbia, canada: micromorphology, pedogenic processes and palaeoenvironmental implications.– in: alexander, j. & marriot, s.b. (eds.): floodplains: interdisciplinary approaches. geol. soc. of london, spec. publ., 163, 289–310. mccarthy, p.j. & plint, a.g. (in review): spatial variability of palaeosols across cretaceous interfluves in the dunvegan formation, ne british columbia, canada: palaeohydrologic, palaeogeomorphologic and stratigraphic implications.– sedimentology. mccarthy, p.j., faccini, u.f. & plint, a.g. (1999): evolution of an ancient coastal plain: palaeosols, interfluves and alluvial architecture in a sequence stratigraphic framework, cenomanian dunvegan formation, ne british columbia, canada.– sedimentology, 46, 861–891. mcdonough, k.j. & cross, t. (1991): late cretaceous sea level from a paleoshoreline.– jour. of geophys. res., 96, 6591–6607. mclaurin, b.t. & steel, r.j. (2000): fourth-order nonmarine to marine sequences, middle castlegate formation, book cliffs, utah.– geology, 28, 359–362. mitrovica, j.x., beaumont, c. & jarvis, g.t. (1989): tilting of continental interiors by the dynamical effects of subduction.– tectonics, 8, 1079–1094. north american commission on stratigraphic nomenclature (1983): north american stratigraphic code.– am. assoc. of petrol. geol. bull., 67, 841–875. pang, m. & nummedal, d. (1995): flexural subsidence and basement tectonics of the cretaceous western interior basin, united states.– geology, 23, 173–176. plint, a.g. (1988): sharp-based shoreface sequences and “offshore bars” in the cardium formation: their relationship to relative changes in sea level.– in: wilgus, c.k., hastings, b.s. kendall, c.g.st.c; posamentier, h.w., ross, c.a. & van wagoner, j.c. (eds.): sea level changes – an integrated approach. soc. of econ. paleont. and mineral., spec. publ., 42, 357–370. plint, a.g. (1996): marine and non-marine systems tracts and fourth-order sequences in the early–middle cenomanian dunvegan alloformation, northeastern british columbia, canada.– in: howell, j.a. & aitken, j.f. (eds.): high resolution sequence stratigraphy: innovations and applications. geol. soc. spec. publ., 104, 159–191. plint, a.g. (2000): sequence stratigraphy and paleogeography of a cenomanian deltaic complex: the dunvegan and lower kaskapau formations in subsurface and outcrop, alberta and british columbia, canada.– bull. of canad. petrol. geol., 48, 43–79. plint, a.g. (2002): paleo-valley systems in the upper cretaceous dunvegan formation, alberta and british columbia.– bull. of canad. petrol. geol., 50, 277–296. plint, a.g. & nummedal, d. (2000): the falling stage systems tract: recognition and importance in sequence stratigraphic analysis.– in: hunt, d. & gawthorpe, r.l. (eds.): sedimentary responses to forced regression. geol. soc. spec. publ., 172, 1–17. plint, a.g. & wadsworth, j.a. (in review): sedimentology and palaeogeography of four large valley systems incising delta plains, western canada foreland basin: implications for mid-cretaceous sea-level changes.– sedimentology. plint, a.g., mccarthy, p.j. & faccini, u.f. (2001): nonmarine sequence stratigraphy: updip expression of sequence boundaries and systems tracts in a high-resolution framework, cenomanian dunvegan formaton, alberta foreland basin, canada.– am. assoc. of petrol. geol. bull., 85, 1967–2001. poulton, t.p. (1994): chapter 18: jurassic and lowermost cretaceous strata of the western canada sedimentary basin.– in: mossop, g. & shetsen, i. (eds.): geological atlas of the western canada sedimentary basin. canad. soc. of petrol. geol. and alberta res. council, 217–316. rogers, r.r. (1998): sequence analysis of the upper cretaceous two medicine and judith river formations, montana: nonmarine response to the claggett and bearpaw marine cycles.– jour. of sed. res., 68, 615–631. sahagian, d. & jones, m. (1993): quantified middle jurassic to paleocene eustatic variations based on russian platform stratigraphy: stage level resolution.– geol. soc. of am. bull., 105, 1109–1118. scott, j.j. (2000): fossil vertebrate footprints in the dunvegan formation (upper cretaceous: cenomanian) of british columbia and alberta.– unpubl. bsc thesis, university of saskatchewan, saskatoon, 115 p. shanley, k.w., mccabe, p.j. & hettinger, r.d. (1992): tidal influence in cretaceous fluvial strata from utah, u.s.a.: a key to sequence stratigraphic interpretation.– sedimentology, 39, 905–930. singh, c. (1983): cenomanian microfloras of the peace river area, northwestern alberta.– alberta res. council bull., 44, 321 p. smith, d.g. (1987): meandering river point bar lithofacies models: modern and ancient examples compared.– in: ethridge, f.g., flores, r.m. & harvey, m.d. (eds.): recent developments in fluvial sedimentology. soc. of econ. paleont. and mineral., spec. publ., 39, 83–91. stelck, c.r. & wall, j.h. (1955): foraminifera of the cenomanian dunveganoceras zone from the peace river area of western canada.– res. council of alberta report, 70, 81 p. stelck, c.r., wall, j.h. & wetter, r.e. (1958): lower cenomanian foraminifera from the peace river area, western canada.– alberta res. council, geol. div., bulletin, 2/1, 1–35. 68 geologia croatica 56/1 stoops, g.j. & zavaleta, a. (1978): micromorphological evidence of barite neoformation in soils.– geoderma, 20, 63–70. stott, d.f. (1982): lower cretaceous fort st. john group and upper cretaceous dunvegan formation of the foothills and plains of alberta, british columbia, district of mackenzie and yukon territory.– geol. surv. of canada bull., 328, 124 p. upchurch, g.r. & wolfe, j.a. (1993): cretaceous vegetation of the western interior and adjacent regions of north america.– in: kauffman, e.g. & caldwell, w.e.g. (eds.): evolution of the western interior basin. geol. assoc. of canada, spec. pap., 39, 243–282. van wagoner, j.c., posamentier, h.w., mitchum, r.m., vail, p.r., sarg, j.f., loutit, t.s. & hardenbol, j. (1988): an overview of the fundamentals of sequence stratigraphy and key definitions.– in: wilgus, c.k., hastings, b.s., kendall, c.g.st.c; posamentier, h.w., ross, c.a. & van wagoner, j.c. (eds.): sea level changes – an integrated approach. soc. of econ. paleontol. and mineral., spec. publ., 42, 39–45. vitali, f., longstaffe, f.j., mccarthy, p.j., plint, a.g. & caldwell, w.e.g. (2002): stable isotopic investigation of clay minerals and pedogenesis in an interfluve paleosol from the cenomanian dunvegan formation, n.e. british columbia, canada.– chemical geology, 192, 269–287. williams, g.d. & stelck, c.r. (1975): speculations on the cretaceous paleogeography of north america.– in: caldwell, w.e.g. (ed.): the cretaceous system in the western interior of north america.– geol. assoc. of canada, spec. pap., 13, 1–20. willis, b.j. (1997): architecture of fluvial-dominated valley-fill deposits in the cretaceous fall river formation.– sedimentology, 44, 735–757. manuscript received february 14, 2003. revised manuscript accepted june 20, 2003. 03 mrinjek.indd 1. introduction clastic sediments in the vicinity of virovitica, previously described as late pliocene–early pleistocene in age (galović et al., 1981; marković, 1986), unconformably overlie the pliocene “rhomboidea beds”, and are unconformably overlain by pleistocene loess, lacustrine–marsh silts and clays. these sediments are well exposed in gravel/sand quarries (cabuna, rezovac, bistrica) south of the drava river (fig. 1), and their thickness varies reaching a maximum of 50 m. they are tectonically deformed and, in most cases, dip towards the north or northeast. the basal part of the clastic complex, known as the “belvedere beds”, is alluvial to lacustrine in origin. babić et al. (1978) suggested the late pliocene age, while prelogović & velić (1992) presumed a lower pleistocene age for these sediments. quartz gravels predominate, interbedded with thin beds of arkose sandstones, clays and marls. according to galović et al. (1981) high-grade metamorphic rocks were the source of the clastic material. the real thickness of the gravels can not be measured, because the basal part of these sediments is not exposed at the surface. pliocene alluvial sediments in the drava depression of the virovitica–slatina area, northern croatia ervin mrinjek¹, jasenka sremac¹ and josipa velić² the upper portion of the clastic complex consists of arkose sandstones with very thin clay intercalations. at surface outcrops sands directly overlie the basal “belvedere beds”, but in deep hydrological bore-holes, clay with peat intercalations occurs at the base of these sediments. an early pleistocene age was proposed by babić et al. (1978). a lack of index fossils in these sediments precludes a precise biostratigraphic analysis. 2. lithology the investigated sediments are in most cases horizontal or subhorizontal, tectonically undisturbed, except in the cabuna quarry, where they thin towards the northeast. gravel is predominant in the 5–20 m thick lower portion of the clastic complex, while sand dominates in the upper 10–40 m of the investigated sections. gravel consists almost completely of quartzite clasts (95%), with scarce clasts of sandstones, metamorphic rocks and dolomites. clasts are subrounded to rounded, varying from granule to cobble size. small pebbles (4– 32 mm in diameter) predominate. the largest cobbles are 256 mm wide. clasts are supported with a fine– coarse-grained sand matrix. some units exhibit openframework packing. clast sorting varies from moderate to good. sand is extremely rich in quartzite grains, associated with a stable muscovite and labile, predominantly feldspar component, together with lithoclasts of carbonate and metamorphic rocks. they vary from fineto coarsegrained types, but medium-grained type is dominant. grains are subrounded to rounded, with generally good sorting. bedding is clearly visible. trough-cross to tabular-cross stratified sets are up to 0.4 m thick. most of the sandy portions exhibit synsedimentary deformations. the cross-stratification measurements suggest eastern and northeastern directions of the palaeostreams. fine-grained sediments are silts, clays and marls composed of clay minerals and silt-grade quartz. x-ray analysis has shown that these sediments contain calcite, dolomite, quartz, muscovite–illite, chlorite and smectite (table 1). carbonate minerals (calcite and/or dolomite) could be of detrital or authigenic origin. smectites (predominantly montmorillonites) are possible products of volcanic ash. illite is probably of the same origin geologia croatica 59/1 65–84 26 figs. 4 tabs. zagreb 2006 key words: sheet flow, alluvial fan, sandy braided river system, fossil flora, drava river depression, northern croatia, pliocene. ¹ department of geology and palaeontology, faculty of science, university of zagreb, zvonimirova 8, hr-10000, zagreb, croatia. ² faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, hr-10000, zagreb, croatia. abstract clastic sediments in the vicinity of virovitica (northern croatia) consist of gravels, sands, silt clays and marls. gravels with discontinuous sheet-like geometry are typical for an alluvial fan system. the most abundant sediment, quartz rich sand, originates from a sandy braided river system. silt, clays, and marls were deposited in the flood plain. they contain fossil macroflora indicative of moderate climate conditions, including maidenhair leaves (ginkgo), the presence of which suggests that these sediments were deposited before the pleistocene glaciation. 66 geologia croatica 59/1 (keller, 1970), although it can also be the result of diagenetic processes if the temperature is below 50°c, and potassium ion concentration between 0.2 and 0.3% (bailey, 1987), which is not very likely in this case. quartz and chlorite are also probably of detrital origin. fine-grained sediments alternate with thin intervals (0.2–2 m) of horizontally and cross-stratified sands. 3. methods the architectural-element and bounding surface analysis methods developed by miall (1985, 1988a, b) following earlier work by brookfield (1977) and allen (1983) were used in examination of lateral and vertical facies changes and environmental interpretation. for this purpose, laterally extensive outcrops in the gravel/ sand quarries located between virovitica and slatina (figs. 1 & 2) were selected for study. their sedimentological analysis consists of sketching primary sedimentological features, measuring grain size, and palaeocurrent directions and making photomosaics of the entire length of each exposure. in order to utilize photomosaics properly, maximum resolution and minimum geometric distortion of the features is achieved. characteristic details were noted by close-up photographs. a fig. 1 (a) location map. (b) position of lateral profiles and logs: a) cabuna quarry, b) rezovac quarry, c) bistrica quarry. sample 12 13 14 15 17 cii9 sk phase calcite + + +g +g dolomite + +g +g + +g quartz +g +g +g + + + +g muscovite-illite +g + + + + + + chlorite +g + +g +g +g + + smectite + +g + +g +g table 1 x-ray analysis of fine-grained sediments. legend: g) main mineral in sample; +) accessory mineral in sample; -) no mineral in sample. 67mrinjek, sremac & velić: pliocene alluvial sediments in the drava depression... study of lithological and sedimentary features enabled a six-fold bounding surface hierarchy to be established (table 2) and eight architectural elements (table 3) and 13 lithofacies (fig. 5) were distinguished. 4. lateral profile analysis the contact between lower (gravelly) and upper (sandy) portions of the investigated profiles is sharp, partly marked by an erosion surface with well developed palaeorelief, up to 1 m high (figs. 7a, b, 17a, b). along the b-profile in cabuna quarry palaeosols were detected at the base of sands. 4.1. gravel complex in vertical sections the lower part is generally well sorted, with clearly visible gravel bodies in the form of sheets (element gs) (figs. 3 and 4). the thickness of gravel sheets varies between 10–40 cm, and their lateral extent is from 10 to >20 m. clasts in gravel sheets vary from granules, through pebble, to cobble size. sheets with smaller clasts are more extensive than those with coarser grains. in cobble-sized sheets imbrications of the b-axis are visible, but poorly developed. well developed flat bedding (facies gh) up to the massive, non-stratified portions (facies gm) can be distinguished. sheet base varies from erosionally irregular, to planar, or amalgamated. upper sheet surfaces can be smooth, or also amalgamated. sheets are in most cases composed of a combination of flat-bedded pebble-sized gravels, granule gravels and laminated coarse grained granule sands (facies gh, sh). at some places elements of sheets surround planar cross-stratified sets of sand gravels with pebble-sized clasts, 30–50 cm thick (facies gp) (fig. 6a, b). inclination of foresets is towards the south and southwest. this facies is very scarce in comparison with gh and gm facies. the upper part of the gravel complex is 1–2 m thick, in the cabuna and rezovac quarries it is characterized by horizontaland cross-stratified, 10–30 cm thick gravel sets with pebble or granule-sized clasts (facies gh and gp). set bases are usually erosional and they fig. 2 detailed sedimentological analysis of profile b was done using mountaineering equipment. underlying table 2 bounding surface hierarchy in the pliocene alluvial sediments. 68 geologia croatica 59/1 extend laterally for up to 5 m. cross-stratified sets are wedge-shaped, often with reactivated surfaces. in most cases they are separated from each other by stratified gravel sets. gravel sets are often interbedded with 5–15 cm thick horizontally stratified granular sands, of >3m lateral extent (facies sh) (figs. 4, 8 and 9). some stratified sands are normally graded or massive, or show low angle planar cross stratification, but, in most cases, table 3 summary of architectural elements in the pliocene alluvial sediments. fig. 3 well developed flat bedding gravels (facies gh). stick is 1 m long. profile b, cabuna quarry. fig. 4 gravel sheets (gs) composed of facies gh. the top of the gravel complex is composed of facies gh, sl and sh. stick is 1 m long. profile b, cabuna quarry. 69mrinjek, sremac & velić: pliocene alluvial sediments in the drava depression... they are horizontally stratified (facies sh). their bases are flat to irregular, scarcely concave or indistinct, continuously deposited over the gravels. the median part of the gravel complex at the aprofile in cabuna (fig. 6a, b) is characterized by a well developed erosional basal surface (5th order bounding surface, table 3) with erosional relief of >3 m, incised into a 4 m thick sandy interval. the erosion becomes invisible at the right-side of the profile, due to the complete erosion of the sandy interval (amalgamated gravels). near the erosion surface, gravels are massive or indistinctly stratified, and they contain <0.4 m diameter angular intraclasts of marls and clays (facies ge). the sandy interval is built up of planar to low angle crossstratified sand units, which show synsedimentary deformation. 4.2. sand complex the sandy part of the profiles generally show a fining upward feature. in the cabuna quarries the upper parts of the profiles are represented by ca. 10 m thick packages of fine-grained sediments (profile b) (fig. 7a, b). description of sedimentary structures and architectural elements in the cabuna and bistrica sand-quarries is difficult because of synsedimentary deformation (figs. 7a, b, 10a, b, 11a, b, 17a, b). two types of sedimentation can be distinguished: channel and floodplain sedimentation (table 4). 4.2.1. channel elements sand profiles c1 and c2 (figs. 10a, b, 11a, b) and sandy portions of profiles b in the cabuna quarry (fig. 7a, b), profile d in rezovac quarry (figs. 13 and 14) and profile e in the bistrica quarry (figs. 17a, b) are characterized by vertically superimposed sedimentary units in the form of sheets. sandy sediments consist of 1–8 m thick sandy channel sequences, over 50 m in lateral extent. a complete sequence, with a distinct fining upward trend in the upper portions, can only be observed in profiles b and d. sandy gravels gradually pass into very coarsegrained sands, then fine-grained, crossto horizontally stratified sands overlain by fine grained floodplain sediments (figs. 7a, b, 13 and 14). in other cases sequences are incomplete – the uppermost parts are missing due to erosion. the base of the channel fill (5th order bounding surface, table 3) is irregularly erosional, ca. 1 m incised into the base sediment, and it is built up by mastable 3 (continued). 70 geologia croatica 59/1 sive to indistinctly cross-stratified coarse-grained sands and intraclasts (channel lag) of fine grained overbank sediments (facies ge and se) (figs. 11a, b, and 15). besides the described basal facies, several other sandy facies were observed. planar cross-stratified sets (facies sp) are rather frequent at all localities. these sets extend up to 5 m in lateral view. the thickness of sets varies from 10–40 cm (figs. 16 and 19), usually increasing in a downstream direction, and their basal surface changes from non-erosive to erosive. contact of the foresets and lower boundary surface is angular or asymptotic. looking downstream, modification of foresets can be observed, from angular (with gradient 20– 25°) to asymptotic (gradient 10–15°), or even sigmoid. reactivated surfaces (3rd order bounding surface, table 3) can often be observed in sections parallel to the inclination of foresets. reactivated surfaces are usually less inclined than foresets (gradient 10–20°), and can extend through one or several sets. these surfaces are usually overlain with coarse grained sand, with scattered granfig. 5 legend for profiles and logs and lithofacies description. 71mrinjek, sremac & velić: pliocene alluvial sediments in the drava depression... ules. in most cases, the inclination of foresets below and above the reactivated surface is similar. trough cross-stratified sand units (facies st) are less frequent in the studied profiles. they occur as isolated sets or cosets (fig. 18). trough sets are 10–30 cm thick, with 40–80 cm wide troughs. their foresets are asymptotic in the base, which is either irregular, or partly concave, due to erosion. they consist of medium to coarse grained sand. inclination of foresets is from 10–20°, and the position of the trough axis is towards the north fig. 6 (a) photomosaics of profile a. cabuna quarry. (b) detailed sketch of profile a. legend is shown in fig. 5. lithofacies and element description and interpretation are shown in fig. 5 and tables 2 and 3. a b 72 geologia croatica 59/1 or northeast. at the base of a trough, sands are in most cases coarse grained, with a high percentage of granules and even small pebbles. within the trough cross-stratified sets it is hard to distinguish bounding surfaces from reactivation surfaces. sets usually overlie erosional surfaces (5th order bounding surface), and partly alternate with planar cross-stratified and horizontally stratified sand sets. horizontally stratified sands (facies sh) are present in relatively thin intervals (0.1–2 m; fig. 19). they overlie the irregular erosional surface, or alternate with planar cross-stratified sands. in the former they contain coarse-grained sand with scattered granules, and are 0.5–2 m thick. horizontally stratified sands extend laterally up to 10 m. in some cases, downstream, they become low-angle planar cross-stratified sets (facies sl). at profiles e and b a concave depression (5th order bounding surface) can be observed (figs. 7a, b, 17a, b and 20). it is symmetrically infilled with facies si and sl, and therefore resembles the infill of small channels. it is impossible to reconstruct the 3d geometry, but it is obvious that the axis dips in an upstream direction. therefore it is presumed that the depression is troughlike rather than an elongate cylinder in shape. its dimensions are 3.6x12.5 m. 4.2.2. flood plain elements the upper part of profile b and the uppermost portion of profile d are composed of silt clays and marls, alternating with mediumto fine grained sands and silts (figs. 7a, b, 12–14). fine grained beds are 0.1–1.2 m thick, massive or horizontally stratified. locally, these sediments contain numerous remnants of fossil macroflora (table 4; figs. 21–23). sand and silt intervals take the form of sheets or lenses, with irregular erosive to concave bases (figs. 7a, b, 12 and 14). they are 0.2–2 m thick, extending laterally from 5 to >20 m. they consist of low angle crossstratified to horizontal stratified units, 0.05–0.3 m thick. thin ripple sets can be observed in the upper portions of these bodies. 5. interpretation 5.1. gravel complex the vertical and lateral characteristics of gravel sheets (element gs) indicate that these sediments were deposited from catastrophic unconfined sheet flows that expand as they move down the steep slope of an alluvial fan, probably when leaving the channel at the top of the fan. such sediments can be clearly distinguished from other gravitational flows due to their different hydraulic features (high froude number, abrupt decrease of flow intensity, rapid deposition of material). flow conditions were in most cases supercritical, due to the steep slope. alternation of transportation and depositional phases of the coarseand fine-grained gravel was caused by changes in hydraulic conditions during the expansion of flow and the decrease in slope inclination, as well as the autocyclic variations of depth and velocity of the supercritical flow. a large number of gravel sheets could have been deposited from a single catastrophic flow (blair, 1987). facies gp represents deposition from antidunes (fig. 6a, b), which were moving together with the largest gravel clasts in the period of maximum velocity and plant group species ginkgoes ginkgo adianthoides (unger) heer flowering plants a. hamamelididae hamamelidales liquidambar europaea a.brongniart fagales fagus haidingeri kovats “quercus” ex.gr. mediterranea unger “q.” cf. lonchitis unger “q.” kamischinensis göppert betula alba linné alnus julianaeformis (sternberg) kvacek & holly carpinus betulus linné urticales ulmus laevis pallas myricales myrica lignitum (unger) saporta myrica sp. b. rosidae fabales (=leguminosae) leguminosae gen. et sp. indet. sapindales acer platanoides linné table 4 flora found in facies fm and fl. profile b. cabuna quarry. 73mrinjek, sremac & velić: pliocene alluvial sediments in the drava depression... height of the flow (blair, 1987). smaller, pebble and granule sized clasts, as well as sands, could have been suspended-load. massive gravel overlying the erosional surface in profile a (fig. 6a, b) was probably deposited from gravity flows (currents) in the incised fan channel (blair & mcpherson, 1994). according to the lithology, facies associations and depositional processes, it can be concluded that the gravelly part of the section probably represents deposits of alluvial fans, with dominant gravel sheet facies. blair & mcpherson (1994) concluded that the majority of recent alluvial fans were deposited from cohesive debrite-flows (type i alluvial fan), or from rapid streams in the form of sheets (type ii alluvial fan), which depend on the lithological conditions, as a b fig. 7 (a) photomosaics of profile b. cabuna quarry. (b) detailed sketch of profile b. legend is shown in fig. 5. lithofacies and elements description and interpretation are shown in fig. 5 and tables 2 and 3. fig. 8 alternation of facies gh, gp and sh on the top of the gravel complex. stick is 1 m long. profile b, cabuna quarry. 74 geologia croatica 59/1 fig. 9 facies gh and gm with lens-like facies sh and sl on the top of the gravel complex. scale is 10 cm long. profile d, rezovac quarry. well as on weathering processes in the fan drainage area. investigated gravels originate from a hinterland composed of quartz conglomerates and sands and/or rapidly uplifted and eroded granites and gneisses. north and north–east palaeotransport directions indicate a possible source area – the crystalline massifs of the psunj and bilogora mts. hard rocks of different lithologies must have been poorly chemically, but strongly mechanically weathered. this can be concluded from the dominant sheet elements and their lithological composition, with the absence of clays. facies types in the upper part of the gravel complex could represent deposits from a very shallow braided river system, with low longitudinal bars deposited during the decrease of the catastrophic flow, or between the two catastrophic flows, during the phase of erosion processes and modification of fan morphology. such secondary processes are particularly common in type ii alluvial fans, due to the erosive capacity of their surfaces (blair & mcpherson, 1994). 5.2. sandy complex 5.2.1. channel elements the main feature of the sandy portions of the analyzed profiles is the presence of sandy channels (element ch), which were in most cases deposited by torrents or floods. rapidly deposited channel complexes consist of dunes (element du), lateral or downstream elements (element dla), linguoid bedforms (lb) and laminated sand sheets (ls). down-stream and lateral accretion macroforms (dla), with radial distribution of migration directions, and overlain by du and/or ls elements, can be compared with cross-channel bars (cant & walker, 1978) or with mid-channel or side bars (miall, 1988b). the thickness of dla elements varies from 0.5–3 m, depending on the channel depth and growth direction (parallel, oblique or perpendicular to the main direction of the palaeostreams). though it is impossible to determine their exact length and width in the profiles, it is obvious that they were longer than 15 m. in most cases these units decrease in thickness and grain size upwards, due to the decline of the stream and long term deposition by moderate to slow streams (miall, 1991). laterally broad (0.5–2 m wide; >30 m long) ls elements are common within the channel complex. thin, but prominent scour fills (sf), parting lineation and numerous granules within the sh facies indicate rapid deposition during the upper flow regime, and turbulent conditions, with a velocity probably in excess of 1 m s-1 (harms et al., 1975; allen, 1983, 1984). analysis of the geometry of the sedimentary body and the facies has shown the presence of long and narrow macroforms, possibly “plane-bedded simple bars” (pbsb) or compound bars described by allen (1983) or “planebedded macroforms” (pbm) as described by miall (1988). it can be concluded that they were the result of seasonal changes in permanent, long-lasting flows. lb elements are relatively scarce on dla and ls elements (profiles c1, c2 and d). they were deposited during decreases in the flow intensity. each of the elements described above, can be partly interpreted as a segment of a complex, large and longlasting macroform, probably a sand flat sensu cant & walker (1978). under such conditions, the upper parts of dla elements, which would be exposed during reductions in the flow rate, could represent a core, from which complex sand flats were deposited, through vertical aggradation and down-stream accretion. dune elements (du) migrated down the deeper parts of a channel and/or covered sand bodies or sand flats (dla, ls, lb), during periods of decreased flow rate or during the low-intensity flows. in most cases palaeocurrent directions are similar. locally, dunes could have migrated obliquely or transversely to the main palaeocurrent direction (e.g. on the flanks of sand flats). the origin of depressions (hf element) can be attributed to processes producing deep incisions where channels converged. such processes were investigated both in the field and under laboratory conditions (mosley, 1974; best, 1988). these studies have shown that deep erosion is typical for channel junctions, which 75mrinjek, sremac & velić: pliocene alluvial sediments in the drava depression... fig. 10 (a) photomosaics of profile c1. cabuna quarry. (b) detailed sketch of profile c1. legend is shown in fig. 5. lithofacies and elements description and interpretation are shown in fig. 5 and tables 2 and 3. a b are common in braided river systems (best, 1988). comparing different localities, current directions are variable, despite the low meandering rate of the river system. therefore, significant dispersion of palaeocurrent directions can be observed. lateral migration of the main channels was a continuous process, resulting in destruction or modification of sand flats. avulsions, as well as aggradations and channel interruptions were 76 geologia croatica 59/1 a b fig. 11 (a) photomosaics of profile c2. cabuna quarry. (b) detailed sketch of profile c2. legend is shown in fig. 5. lithofacies and elements description and interpretation are shown in fig. 5 and tables 2 and 3. common. main channels were shallow (1–8 m, usually 1–3 m deep), very wide (>50 m), low grade sinusoidal (not highly meandering), with a general direction towards the north–east and east. according to the geometry of the sediments, lack of palaeosols and palaeobotanical data, it can be concluded that the climate was humid, which enabled permanent streams, with periodic (seasonal?) flooding. the sandy parts of the profiles can be interpreted as rapidly deposited sediments in wide, low-meandering and complex channel environments. presumed channel activities were similar to those in recent sandy braided rivers (smith, 1970; miall, 1977; cant & walker, 1978). 5.2.2. flood plain elements the upper part of profile b represents a relatively thick (10 m) sequence of flood plain (lacustrine?) deposits, laterally extending for more than 60 m. sheet-like overbank fines (element of) deposited after infilling of the channels by torrents are dominant, with several interstratified crevasse splays (element cs), deposited in shallow stagnant water on a flood plain after the penetration of levees. they are composed of rapidly deposited sands (facies sh and sl), which are, in some places convoluted and overlain by facies sr, deposited during the declining flow. sheet geometry and fine grain size indicate that these sediments were deposited distally from the main channel, although precise distances can 77mrinjek, sremac & velić: pliocene alluvial sediments in the drava depression... fig. 12 logs b and c. legend is shown in fig. 5. cabuna quarry. not be determined on the profile. dominant cs elements and a lack of palaeosols indicate frequent flooding episodes. well preserved plant fossils were discovered in the fine-grained sediments. flowering plants (angiosperms) are more common than gymnosperms (ginkgoes only) (table 4). maple (acer) and hornbeam (carpinus) remnants predominate (figs. 22 and 23). liquidambar, myrica and mediterranean oaks are relics of the miocene–middle pliocene warm period. warming may have been related to changes in ocean circulation patterns, possibly combined with the greenhouse effect (chanb' fm <;0 51 51 <;0 fm <;0 overbank 5, 45 51 channel 20 51 "'[.. fill fi <;0 , " " fm <;0 channel " fill fm <;0 " 5, --5, sh , fi 40 " { sh 5, 15 5, sh crevasse 51 splay 51 channel ,1 i. fill 51 sh /. channel " fill 35 sh, ge,se 10 51 ! ,! 5, '1, 'r, 51 channel " fill " ..-p /, 51 channel channel fill "& fill , , 30 sh " 5, 5 gh 5 sh gh ,/,/ aluvial , channel fill sh fan gm aluvial fan sh gh 25 mo m mean grain size interpretation interpretation 78 geologia croatica 59/1 fig. 13 numerous sets of planar cross-stratified sands in the upper part of log d. part of log d is about 10 m long. rezovac quarry. see legend on fig. 5. fig. 14 log d. rezovac quarry. legend is shown in fig. 5. lithofacies and element description and interpretation are shown in fig. 5 and tables 2 and 3. dler, 1997). the presence of betulaceans (beech, alder) indicates cooling of the climate, typical for the end of the pliocene. maples and hornbeams are known as the first colonizers of the unconsolidated soils. ginkgo adianthoides (fig. 21) similar to its recent congeneric, g. biloba linné, is an ecologically conservative genus. throughout the late cretaceous and cenozoic, it was largely confined to disturbed streamside and levee environments (royer et al., 2003), and it can not be found at european and american localities after the pliocene (see www.ucmp.berkeley.edu/seedplants/ ginkgoales/gingkofr.html). thin, fine grained sediments (of) in the uppermost part of profile d (rezovac) were probably deposited on sand flats during a low water stand, when most of these sand macroforms acted as islands. of elements were emergent and partly eroded during the periodic floods. 6. deformation structures synsedimentary deformation of loose sands are well developed at the investigated localities. ls and du elements (table 4) in profiles b, c1 and c2 (figs. 7a, b, 10a, b, 14a, b) are partly or completely convoluted. convolution can be described as a series of steep, high (0.5–1.5 m) antiforms divided by 1–3 m wide synforms. in most cases convolution was single phased, and it did not include previously deformed, cross-stratified sands. large scale, multiphase deformation was observed exclusively within ls elements in profiles b and c1. such deformation includes several sets, and is abruptly interrupted in the base by a synsedimentary reverse fault (fig. 24). small blocks of massive sand indicate synsedimentary slumping. this deformation is also marked with antiforms, slightly overturned in the palaeocurrents direction. oversteepening and overturning can also be observed within isolated sets of hf, dla and lb elements (fig. 25). deformations vary from foresets inclined more than the angle of rest to overturned foresets which resemble the overturned folds. deformation increases in the upper part of the profiles. convolute deformations are partly of intrinsic origin, produced by synsedimentary processes (leeder, 1987). allen (1984) interpreted these processes as 79mrinjek, sremac & velić: pliocene alluvial sediments in the drava depression... fig. 15 base of sand channel (5th bounding surface) overlain by facies ge and se. hammer is 30 cm long. profile c2. cabuna quarry. fig. 16 sets of planar cross-stratified sands (facies sp) and horizontally stratified sands (facies sh). transition from planar cross-stratified sands to low-angle cross-stratified sands (facies sl) and reactivation surfaces can be observed. stick is 1 m long. profile c2. cabuna quarry. fig. 17 (a) photomosaic of profile e. bistrica quarry. (b) detailed sketch of profile e. legend is shown in fig. 5. lithofacies and elements description and interpretation are shown in fig. 5 and tables 2 and 3. a b 80 geologia croatica 59/1 fig. 18 sets of trough cross-stratified sands (facies st, element du) overlain by sets of low-angle planar cross-stratified and horizontally stratified sands (facies sl and sh, element ls). stick is 1 m long. profile c1. cabuna quarry. fig. 19 sets of planar cross-stratified sands (facies sp) and horizontally stratified sands (facies sh). transition from horizontally stratified sands (facies sh) to low-angle cross-stratified sands (facies sl). stick is 1 m long. profile c2. cabuna quarry. metaand synsedimentary events, which took place during rapid deposition, or immediately after sedimentation. liquefaction processes were triggered by the unstable density gradient. intensive, polyphase, laterally extensive deformations in profiles b and c1 influencing whole set packages, suggest extrinsic origin. seismic shocks were the probable cause of these events, as indicated by the following features: (1) size and extent of deformational structures; (2) deformed/undeformed sand body ratio; (3) synsedimentary faults; (4) proximity of the main transcurrent fault. rapid subsidence enabled the successful burial of sands and their saturation for liquefaction caused by seismic activity. an earthquake epicenter could not be precisely detected, but was probably situated within 20 km, considering the fact that a magnitude of at least 5 is necessary for the liquification of loose, saturated, fineto medium-grained sands. in case of magnitude 7, the epicenter could have been within 40 km (idriss, 1985). the southern marginal fault of the drava depression is within these distances, and was the most probable location for the epicenter. 7. tectonic setting the investigated area is situated along the southern margin of the drava depression (according to the petroleum-geological division), within the southwestern part of the pannonian basin system, which territorially belongs to the republic of croatia. this is an area of extremely strong tectonic processes, clearly divided into three periods, resulting in the formation of corresponding tectonic structures (prelogović et al., 1995, 1998; lučić et al., 2001; saftić et al., 2003): (1) initial structural changes during the oligocene and early miocene. the onset of extensional tectonics, subsidence and sedimentation began as a result of the first syn-rift extensional tectonic phase; 81mrinjek, sremac & velić: pliocene alluvial sediments in the drava depression... fig. 20 concave depression (element hf) symmetrically infilled with facies si and sl. the right side of the depression shows synsedimentary deformation. depression is 1.5 m deep. profile e. bistrica quarry. fig. 21 ginkgo adianthoides (unger) heer. fig. 22 carpinus betulus linné. fig. 23 acer platanoides linné. (2) major extensional processes during the early and middle miocene; (3) new reshaping processes (prevailing transpression) during the pliocene, which is still present today. this model is dominated by wrench-faults. according to the structural composition, three main zones can be distinguished, comparable with the western, southern and central marginal portions of the pannonian basin system. they are outlined by the dominant regional faults: the periadriatic–drava fault, the medvednica fault zone and the southern marginal fault of the pannonian basin. the explored outcrops of the pliocene clastic sediments are situated south of the virovitica–slatina line, on the northern slopes of the bilogora and papuk mts. their genesis was strongly influenced by tectonic processes, in relation to palaeogeographic conditions and climatic changes. this area is situated at the boundary between two large structures – the uplifted bilogora and papuk mts. and subsided drava depression. (fig. 26). this boundary is identical to the nw striking dextral periadriatic–drava wrench fault. according to seismotectonic analysis (prelogović et al., 1998), this fault actually represents a 5 km wide zone. after the first 7 kilometres of depth, which are characterized by a reverse movement of the hanging wall, this fault becomes almost vertical. its position, width of the fault zone and dimensions of displacement were presented by saftić et al. (2003). one of the indicators of the presence of a fault is the sediment thickness, deposited due to its influence. 82 geologia croatica 59/1 fig. 24 synsedimentary deformation expressed by overturned antiforms abruptly interrupted in their base by a synsedimentary reverse fault. oversteepening and overturning can be also observed within isolated sets in the upper part of the photograph. the antiforms are about 1 m high. profile c1. cabuna quarry. fig. 25 synsedimentry deformation expressed by oversteeping and overturning in the middle part of photograph. oversteepened and overturned interval is 1 m thick. profile c1. cabuna quarry. in the vicinity of virovitica, the extreme depth (sometimes exceeding 6000 m) of the sediment filled neogene–holocene basin was observed (velić et al., 2002; saftić et al., 2003). extreme values were particularly measured for the sediments of the pliocene, pleistocene and holocene, which are of great interest here. northeast of virovitica and slatina, more than 1,500 m thickness was measured in these sediments. these data clearly emphasize the pliocene–holocene synsedimentary tectonic activity, which enabled the formation of such a prominent depositional centre. the investigated clastic sediments belong to the 3rd megacycle, formed during pliocene to holocene basin inversion resulting in subsidence in the deepest zones, associated with uplift and – particularly important – erosion of the most elevated blocks (velić et al., 2002; saftić et al., 2003). rapidly uplifted blocks, the slavonian mts., bilogora and papuk mts. represented the source area for the redeposited clastic material (well rounded pebbles of quartz, quartzite and other materials), combined with the influence of the moderately warm climate and intense precipitation (chandler, 1997). 8. conclusions (1) the detailed analysis of lateral profiles exposed in sand/gravel quarries along the southern edge of the drava depression, between virovitica and slatina, show the existence of a complex and variable alluvial system during the late pliocene. (2) gravels in the lower portion of profiles a, b, d and e were deposited in alluvial fans. gravel sheets deposited during catastrophic floods predominate. the composition and lithological features of the gravels indicate a tectonically uplifted and disturbed hinterland, composed of conglomerates and sands, with predominant mechanical weathering. granites and gneisses are less probable as the source of the material, because well rounded quartz clasts suggest multiple phases of redeposition. (3) north and northeastern directions of palaeostreams, derived from clast imbrications, are more or less perpendicular to the direction of the main drava fault, indicating the psunj and bilogora areas as a possible source for clasts. (4) preservation of alluvial fans in the investigated area suggests deposition in an extensive or transtensive 83mrinjek, sremac & velić: pliocene alluvial sediments in the drava depression... fig. 26 tectonic setting of the study area (from lučić et al., 2001). land environment, surrounded by steep faults of vertical and/or horizontal character, which confirms the previously published data on tectonics in the wider area. (5) sandy facies of the braided river, which erosively overlie the alluvial fans, indicates the decline of tectonic activity. climatic changes into a stable, moderately humid climate, could also be a reason for depositional changes thus forming fining upward fluvial cycles (fig. 12). (6) deformation structures indicate the vicinity of earthquake epicenters, and extensional and transtensional faults. (7) source of the clastic material was probably relatively close, ca. 10 km south or southwest of the investigated area. (8) although the dominant flow direction of the main channel was subparallel to the palaeodirections on the fans, and very near the active faults, the water source could have been tens of kilometers or more from the source area of the clastic material in the alluvial fans. acknowledgement the authors gratefully appreciate and acknowledge the reviews by györgyi juhász and josip tišljar whose comments significantly improved this paper. 9. references allen, j.r.l. (1983): studies in fluviatile sedimentation: bars, bar-complexes and sandstone sheets (low-sinuosity braided streams) in the brownstones (l. devonian), welsh borders.– sediment. geol., 33, 237–293. allen, j.r.l. (1984): sedimentary structures, their character and physical basis.– development in sedimentology, 30, 663 p. babić, ž., čakarun, i., sokač, a. & mraz, v. (1978): o geologiji kvartarnih naslaga porečja rijeke drave [geology of the quaternary deposits in the drava river basin – in croatian].– geol. vjesnik, 30/1, 43–61. bailey, s.w. (1987): micas.– reviews in mineralogy, 13, mineralogical society of america, xii+584 p., washington. best, j.l. (1988): sediment transport and bed morphology at river channel confluences.– sedimentology, 35, 481–498. blair, t.c. (1987): sedimentary processes, vertical stratification sequences, and geomorphology of roaring river alluvial fan. rocky mountain national park, colorado.– jour. sed. petrol., 57, 1–18. blair, t.c. & mcpherson, j.g. (1994): alluvial fans and their natural distinction from rivers based on morphology, hydraulic processes, sedimentary processes, and facies assemblages.– jour. sed. petrol., a64/3, 450–489. brookfield, m.e. (1977): the origin of bounding surfaces in ancient aeolian sandstones.– sedimentology, 24, 303–332. 84 geologia croatica 59/1 cant, d.j. & walker, r.g. (1978): fluvial processes and facies sequences in the sandy braided, south saskatchewan river, canada.– sedimentology, 25, 625–648. chandler, m.a. (1997): the climate of the pliocene: simulating earth’s last great warm period.– http://giss. nasa.gov/research/features/pliocene. galović, i., marković, s. & magdalenić, z. (1981): osnovna geološka karta sfrj 1:100000. tumač za list virovitica, l33–83 (basic geological map of sfry 1:100,000. geology of virovitica sheet). – inst. geol. istraž. zagreb (1976), savezni geol. zavod, beograd, 44 p. harms, j.c., southard, j.b., spearing, d.r. & walker, r.g. (1975): depositional environments as interpreted from primary sedimentary structures and stratification sequences.– sepm, short course 2, 161 p. idriss, i.m. (1985): evaluating seismic risk in engineering practice.– in: proceedings of 11th international conference on soil mechanics and foundation engineering, a.a. balkema publishers, rotterdam, 255–320. keller, w.d. (1970): symposium papers on enviromental aspects of clay minerals.– jour. sed. petrol., 40/3, 788– 813. leeder, m.r. (1987): sediment deformation structures and palaeotectonic analysis of sedimentary basins with case study from carboniferous of northern england.– in: jones, e.m. & preston, r.m.f. (eds.): deformation of sediments and sedimentary rocks. geological society, london, 29, 137–146. lučić, d., saftić, b., krizmanić, k., prelogović, e., britvić, v., mesić, i. & tadej, j. (2001): the neogene evolution and hydrocarbon potential of the pannonian basin in croatia.– marine and petroleum geology, 18, 133–147. marković, s. (1986): osnovna geološka karta sfrj 1:100.000. tumač za list podravska slatina, l33–84 (basic geological map of sfry 1:100,000. geology of podravska slatina sheet).– inst. geol. istraž., zagreb (1984), savezni geol. zavod, beograd, 43 p. miall, a.d. (1977): a review of the braided-river depositional environment.– earth science reviews, 13, 1–62. miall, a.d. (1985): architectural-element analysis: a new method of facies analysis applied to fluvial deposits.– earth sci. rev., 22, 261–308. miall, a.d. (1988a): architectural elements and boundary surface in fluvial deposits: anatomy of the kayenta formation (lower jurassic), southwest colorado.– sedimentary geology, 55, 233–262. miall, a.d. (1988b): facies architecture in clastic sedimentary basins.– in: kleinspehn, k. & paola, c. (eds.): new perspectives in basin analysis. springer-verlag, new york, heidelberg, berlin, 67–81. miall, a.d. (1991): hierarchies of architectural units in terrigenous clastic rocks, and their relationship to sedimentation rate.– in: miall, a.d. & tyler, n. (eds.): the three-dimensional facies architecture of terrigenous clastic sediments and its implication to hydrocarbon discovery and recovery. sepm (society for sedimentary geology). concepts in sedimentology and palaeontology, 3, 6–12. mosley, m.p. (1974): an experimental study of channel confluences.– journal of geology, 84, 535–562. prelogović, e. & velić, j. (1992): correlation of quaternary sediments and tectonic activity of the eastern part of the drava river depression.– geol. croat. 45, 151–162. prelogović, e., jamičić, d., aljinović, b., velić, j., saftić, b. & dragaš, m. (1995): dinamika nastanka struktura južnog dijela panonskog bazena [structural dynamics in southern part of the pannonian basin – in croatian].– 1 . hrv. geol. kongr., opatija, zbornik radova, 2, 397–398, zagreb. prelogović, e., saftić, b., kuk, v., velić, j., dragaš, m. & lučić, d. (1998): tectonic activity in the croatian part of the pannonian basin.– tectonophysics, 297, 283–293. royer, d.l., hickey, l.j. & wing, s.l. (2003): ecological conservativism in the “living fossil” ginkgo.– paleobiology, 29/11, 84–104. saftić, b., velić, j., sztanó, o., juhász, g. & ivković, ž. (2003): tertiary subsurface facies, source rocks and hydrocarbon reservoirs in the sw part of the pannonian basin (northern croatia and south-western hungary).– geol. croatica, 56/1, 101–122. smith, n.d. (1970): the braided stream depositional environment: comparison of the platte river with some silurian clastics rocks, north-central appalachians.– bull. geol. soc. am., 81, 2992–3014. velić, j., weisser, m., saftić, b., vrbanac, b. & ivković, ž. (2002): petroleum-geological characteristics and exploration level of the three neogene depositional magacycles in the croatian part of the pannonian basin.– nafta, 53/6–7, 239–249, zagreb. wizevich, m.c. (1991): photomosaics of outcrops: useful photographic techniques.– in: miall, a.d. & tyler, n. (eds.): the three-dimensional facies architecture of terrigenous clastic sediments and its implication to hydrocarbon discovery and recovery. sepm (society for sedimentary geology). concepts in sedimentology and paleontology, 3, 22–24. manuscript received december 12, 2004. revised manuscript accepted june 9, 2006. medunic.indd �ab stra ct soils from an industrial zone in garešnica, croatia have been analysed by edxrf and xrd. in the area surrounding two adjacent factories named ‘bakrotisak’ and ‘croatia protekt’, thirty soil sites (depth 5–15 cm) were sampled in december 2007, together with fi ve soil sites from the forest (control samples) situated 0.5 km away. the locality was selected for its periodic, industrially induced environmental pollution which affects nearby streams and fi sh ponds, resulting in occasional fi sh kills in the region. analysis included the determination of soil mineralogy, total organic matter content, cation exchange capacity, bulk multi-element composition and trace metal levels in leachates (exchangeable fraction). multi-element concentrations in the control samples constituted natural background levels. the kruskal-wallis test showed higher, statistically signifi cant (p<0.001) concentrations of cu in the soil surrounding ‘bakrotisak’ compared to the control samples. furthermore, leaching analysis confi rmed copper contamination of the ‘bakrotisak’ soil, as shown by the highly signifi cant positive correlation, (the kendall’s tau correlation coeffi cient >0.99) between its extractable cu and total cu levels. moreover, enrichment factors of cu based on al as a reference element are found to be >2 for approximately 50% samples of the ‘bakrotisak’ soil, suggesting moderate anthropogenic contamination. keywords: urban soil, anthropogenic impact, trace metal leaching, enrichment factor, ‘bakrotisak’ factory, garešnica, croatia distribution of copper and zinc in the soil of an industrial zone in the city of garešnica, croatia � gordana medunić1, nenad tomašić1, dražen balen1, višnja oreščanin2, esad prohić1, štefi ca kampić1 and danijel ivanišević1 1 faculty of science, university of zagreb, horvatovac 95, hr-10000 zagreb, croatia; (gpavlovi@inet.hr) 2 uskni, laboratory for applied nuclear analytics, a. jakšića 30, zagreb, croatia doi: 10.4154/gc.2009.13 geologia croaticageologia croatica 1. introduction garešnica is a small town with approximately 11600 residents, situated in the central part of croatia at the foot of the moslavačka gora hill. its industrial zone includes the ‘bakrotisak’ (b) and ‘croatia protekt’ (cp) factories, which have been in operation for the last thirty years. b is a chemical factory that produces fl exible packaging products for the food, confectionery, pharmaceutical and tobacco industries, whereas the main activity of cp is rubber tyre protection. although they both currently comply with offi cial environmental policy, in b’s beginnings there was an accidental spill of organic liquid waste which caused one of the numerous fi sh kills in nearby fi sh ponds. in addition, the local drainage system is composed of a number of streams, the largest of which is the ilova river. it drains the upstream area around grubišno polje which has a long tradition in the dairy industry. in the past, such a food industry did not have proper purifi cation facilities and pollution fl uxes purposely or accidentally released into the ilova river, obviously affecting the ecosystem downstream. geologia croatica 62/3 179–187 5 figs. 3 tabs. zagreb 2009 geologia croatica 62/3geologia croatica 180 ogy of area was published in the croatian geological so ciety excursion guide book for the moslavačka gora (crnko, 1998) and by jurak et al. (2006) where the youngest sediments are methodically described according to unpublished geological map for the kutina sheet. the quaternary sediments extensively cover the research area and occur in different facies including the alluvium of recent fl ows, colluvium − proluvium deposits and organogenic swamp and fl ood-plain sediments. alluvial sediments occur in the recent river valleys streaming from the moslavačka gora and feeding the garešnica river which passes through the study area (fig. 1). the sediments are composed of gravels, sands and silts of variable lithological composition comprising fragments of metamorphic and igneous rocks, limestones, sandstones and fossil fragments. in the pleistocene, swamp and terrestrial loess produce a nonuniform complex alternating with terrestrial silts, swamp silts to clays and alluvial (mud and gravel) deposits (fig. 1). the neogene is characterised by sediments (gravels, sands, silt and clays) and sedimentary rocks (limestones, marl, silty marl, sandstone and conglomerate) (fig. 1). differences in the local source area accompanied by separation processes and possible contributions from distant sources, (kovačić & grizelj, 2006) infl uence the local variability of sediments and sedimentary rocks. the crystalline complex of the moslavačka gora is composed of granite and varieties of medium-grade metamorphic rocks including gneiss, migmatite, amphibolite, micaand cordierite-schists (fig. 1). weathering of granite and medium grade metamorphic rocks of the moslavačka gora crystalline complex mainly contribute (d) to the materials comprising the sediments and sedimentary rocks of the research area. the investigated area is covered by humic cambisols (špoljar, 1999) characterised by their high moisture content as a consequence of high precipitation, fl ooding and high groundwater level (škorić, 1986). in figure 1 numbers 1–15 is soil samples collected in the vicinity of the b and cp factories, constituting a total of 30 samples. the samples were collected every ten metres avoiding the local industrial infrastructure. control samples (k) 1–5 were taken randomly in the forest soil developed upon the swamp and terrestrial loess, and recent fl ood sediments rich in siliceous fragments of acid igneous and medium-grade metamorphic rocks. urban and control soil samples were all rather similar in their visual appearance, i.e. texture. however, the control samples were somewhat darker and more waterlogged in comparison to the urban soils groups. at each location, after removing the top 5–10 cm of vegetative cover, approximately 1 kg of soil sample was taken with the sampling shovel. all samples were dried at 105 °c, then sieved through 0.5 mm and disaggregated in an agate mortar for further analysis. 2.2. analytical methods all solid samples were analysed for multi-element composition (al, k, ca, ti, v, cr, mn, fe, co, ni, cu, zn, pb, ga, as, rb, sr, y, zr) by energy dispersive x-ray fl uorescence macklin (1992) describes the metal pollution of soils and sediments in the context of production-related activities (mining, smelting, etc.) and consumption-related activities (use, wear and disposal of consumer and commercial products). sources of soil contamination in urban areas have been discussed by thornton (1990), and are grouped as follows: construction of buildings and demolition, household activities, waste disposal, transport, industry, and power stations. among the aforementioned, factors infl uencing the b and cp soils would be industry and waste disposal (b – all sorts of liquid chemicals; cp – useless old tyres). over the last few decades much attention has been directed towards the geochemical patterns of soil pollution as soils are the ultimate sink for metals in the terrestrial environment (warren & birch, 1987; li & thornton, 2001; oreščanin et al., 2003; martley et al., 2004). a growing body of literature is focused on assessing soil pollution by copper (kuo et al., 1983; merrington & alloway, 1994; graedel et al., 2002; spatari et al., 2002; bertram et al., 2002; hu et al., 2006; li et al., 2006). so far, there has been no local sampling dealing with soil geochemistry in the moslavina region. garešnica is a city where the key sources of employment and income are the aforementioned b and cp factories as well as several others from the wood processing and textile industries. in spite of a general opinion that the county has a good environment, it must have been infl uenced by the presence of such longterm industry. copper (cu), lead (pb), cadmium (cd), and zinc (zn) are the principal metals of concern in environmental surveys because they are often the main metal constituents of air pollutants and have known toxicities to biota (adriano, 1986). this paper evaluates the infl uence of three decades of industrial activities on neighbouring soil in the context of metal pollution, starting with the geochemical and mineralogical characterisation of soil in the vicinity of the b and cp factories. soil samples from a nearby control site are used in the discussion as being representative of natural background levels. using statistical methods, total and extractable trace metal concentrations are discussed with respect to soil mineralogy, bedrock lithology and anthropogenic setting. 2. materials and methods 2.1. site description and sampling strategy the study area is located in the south-western corner of the pannonian basin near the eastern fl anks of moslavačka gora hill. in the wider area around the sampling sites, quaternary, neogene sediments and sedimentary rocks together with the older moslavačka gora crystalline complex, comprising granite and medium-grade metamorphic rocks occur. since the basic geological map sfry sheet kutina for that area, although produced in the late 1980’s, has never been published, for the broad information on surface geology, we are dependent on the neighbouring map (sheet bjelovar – korolija & crnko, 1985), and related explanatory notes (korolija et al., 1986) for general information on surface geology. however, very useful information about the geolmedunić et al.: distribution of copper and zinc in the soil of an industrial zone in the city of garešnica, croatia geologia croatica 181 fi gu re 1: (a) the location of garešnica within croatia; (b) geological sketch map of moslavačka gora mountain showing the research area, crystalline rocks (black), neogene sediments and sedimentary rocks (dark gray), pleistocene loess (light gray), alluvial sediments of recent river valleys (white); (c) sketch map of the research site with sampling localities (b – the 'bakrotisak' factory, cp – the 'croatia protekt' factory, k – control samples). (edxrf). they were prepared for analysis as follows: 4 grams of each powdered sample (particle size <0.071 mm) were pressed into pellets of 20 mm in diameter (15 tons pressure, 30 s dwelling time). no binder material was added. the samples were placed in standard sample holders and loaded into the minipal 4 x-ray fl uorescence spectrometer (panalytical, almelo, netherlands). spectral data were analysed by minipal/minimate software version 3.0.–63(2.64) (panalytical). a calibration model for qualitative and quantitative analyses was created on the basis of measurements of the following standard reference materials: iaea-sl1 (lake sediment), iaea-soil 7, iaea 405 (stream sediments) and iaea sl 3 (lake sediment). all four standard reference materials were supplied by the international atomic energy agency (vienna, austria). accuracy of the measurements was checked fi rstly by measuring the standard reference materials included in the calibration as unknown samples, while the second check was done by the measurement of 'nist2702' ('inorganic in marine sediments') standard reference material (national institute of standards and technology, broadway, boulder, co, usa) which was not included in the calibration of the spectrometer and could represent a real unknown sample. the goodness of the fi t was checked from the following values: k factor; rms value, relative rms (%) and coeffi cient of correlation. the leaching procedure was as follows: 1 gram of each powdered soil sample (dry weight) was subjected to extraction with 1m nh4oac-ph 7 (exchangeable fraction). the extracts were diluted to 100 ml with double distilled water divided into two subsamples, and adjusted to ph 3 and 11 by the addition of concentrated hno3/nh4oh, respectively. after the ph adjustment, samples were preconcentrated by 1 ml of freshly prepared 1% w/v solution of ammoniumpyroloidinedithiocarbamate (apdc). after the complexation which lasted 20 min, the suspension was fi ltered through a millipore fi lter (0.45 mm) in order to obtain thin targets that were irradiated by x-ray for 300 s. all targets were analys ed by edxrf. the obtained results were multiplied by the dilution factor and the percentage of the extracted element was calculated from the formula: (ctot-ce/ctot)*100 (whe re ctot − mass concentration of the element in bulk sample, ce – mass concentration of the element extracted from the soil). x-ray diffraction analysis was carried out on a philips pw 3040/60 x’pert pro powder diffractometer (panalytical) using cukα radiation (λ = 1.54055 å) at 40 kv and 40 ma. for identifi cation of phyllosilicates the samples were additionally treated in ethyleneglycol vapour for 24 hours, and heated at 400 and 550 °c for 30 minutes in each case. a b c geologia croatica 62/3geologia croatica 182 the cation exchange capacity was determined by mixing the samples with a 0.01 mol dm–3 solution of copper ethylenediamine complex [cu(en)2]2+ (ammann et al., 2005). the subsequent change in cu2+ concentration due to sample adsorption was determined by uv-vis spectrophotometer hach dr/4000 u 8 (hach company, loveland, co, usa) at 548 nm absorption line. the ph of the [cu(en)2]2+ solution upon mixing with each sample was around 7. loss on ignition, as an indicator of the organic matter content of samples, was determined by heating in an oven at 375 °c over 24 h. data processing was performed with the statistica version 7 software. 3. results and discussion the evaluation of possible trace metal pollution linked to industrial activity was studied by a comparison of soil around the b and cp factories with the k samples collected from a nearby forest (fig. 1). numerous papers deal with soil metal concentrations above what would naturally occur, comparing them with the quantifi ed geochemical (natural) background levels refl ecting natural processes uninfl uenced by human activities (salomons & förstner, 1984; hanson et al., 1993; daskalakis & o’connor, 1995; prohić et al., 1995; matschullat et al., 2000; miko et al., 2001; reimann & garrett, 2005; reimann et al., 2005). since the k samples were collected from the forest assumed to represent the study area in its supposed preindustrialization state, their geochemical features will be discussed fi rst, followed by explanation of the chemical and mineralogical nature of the urban soil changes presumably caused by the industrial activity. as the fi rst step in data analysis is estimating the distribution of the measured variables (reimann & filzmoser, 2000), the shapiro-wilk w test shows moderate to perfect normality for all variables in the k samples, except for potassium and cobalt; e.g. the results of the test for cu and zn are as follows: sw–w = 0.97 and 0.88, p = 0.91 and 0.34, respectively. however, the k data (as well as the b and cp data), like any other environmental data, are characterised by the problem of small sample size (gleit, 1985), in which case disproving normality by the hypothesis test is rather diffi cult. therefore, distribution-free nonparametric procedures were employed here. the kendall’s tau correlation matrix was calculated for al, fe, ni, rb, loi, cu, zn, pb, and as. the fi rst fi ve variables in a row represent conservative components, the values of which are commonly unaffected by contaminant inputs, where as the last four are selected trace metals which are commonly enriched as a result of human activities (salomons & förstner, 1984; prohić et al., 1995). the results (table 1) demonstrate a very strong positive correlation between cu and rb (>0.99), strong correlations (0.95) for the pairs fe-rb and fe-cu, and fi nally less strong, but still statistically signifi cant correlations (0.84) for the al-rb, al-loi, al-cu, and al-zn pairs. remaining correlations are all positive (except for fe-ni = –0.11), but not statistically signifi cant. these associations to a large extent have resulted from natural processes occurring in soils formed by the weather ing of acid igneous rocks (loughnan, 1969; hanson et al., 1993), thereby confi rming that the chemical composition of the k soil group could represent localscale background data. cation exchange capacity (cec) determination for the k soil yielded 16.1 meq/100g, and 4.6 meq/100g for the soil after the removal of organic matter. the original soil cec corresponds to soils of loam and silty loam textures. the signifi cant reduction of cec upon organic matter removal indicates the dominant role of organic matter in the adsorption capacity of the investigated soil. indeed, the mineral composition of the k soil comprises quartz, plagioclase, chlorite, mica/illite and kaolinite (fig. 2) without the presence of swelling clay minerals which are strong adsorbents. thus, the determined mineral composition supports low cec values strongly refl ecting the occurrence of the phyllosilicate minerals with general cec values ranging from 5 to 25 meq/ 100g (van olphen & fripiat, 1979; yong & warkentin, 1975). table 1: the kendall’s tau correlation matrix for the k soil group (numbers in bold are signifi cant at p < 0.05; number of samples is 5). al (%) fe (%) ni (ppm) rb (ppm) loi (%) cu (ppm) zn (ppm) pb (ppm) as (ppm) al (%) 1.00 fe (%) 0.76 1.00 ni (ppm) 0.12 –0.11 1.00 rb (ppm) 0.84 0.95 0.00 1.00 loi (%) 0.84 0.53 0.40 0.60 1.00 cu (ppm) 0.84 0.95 0.00 >0.99 0.60 1.00 zn (ppm) 0.84 0.53 0.00 0.60 0.60 0.60 1.00 pb (ppm) 0.36 0.32 0.20 0.40 0.00 0.40 0.40 1.00 as (ppm) 0.60 0.53 0.00 0.60 0.60 0.60 0.20 0.00 1.00 figure 2: xrd patterns representing mineral composition of the k soil (k–1), and two urban soil samples (b–15 and cp–14) selected on the basis of their enrichment in cu (qtz – quartz; chl – chlorite; ms – muscovite/illite; k – kaolinite, plg – plagioclase). medunić et al.: distribution of copper and zinc in the soil of an industrial zone in the city of garešnica, croatia geologia croatica 183 as regards the properties of the b and cp soil groups, a rough inspection of trace metal contents (table 2) shows that cu and zn mean and median values calculated for the b and cp soil groups exceed the values of the control k group. the kruskal-wallis test confi rms that only cu has higher, statistically signifi cant (p<0.001) values in the b soil compared to the k soil. this fi nding obviously indicates a contamination to varying extents which is discussed in further detail below. an opposite trend is shown by pb and as being lower or equal in the b and cp compared with the k group. in view of the fact that there is a local road along the forest where the k samples were taken (fig. 1), their slightly higher pb values are not surprising. lead is known to deposit within 100 m of a road (thornton, 1990). loi values (table 2), ascribed to organic matter content, and were found to be higher in the k group than in the other two groups. the mineralogy of the b and cp soil samples does not signifi cantly differ from the k group containing quartz, plagioclase, chlorite, mica/illite and kaolinite (fig. 2). the presence of swelling clay minerals was not observed. as for the k group, the mineral composition does not presume high adsorption capacities and the cec values determined for the k soil could be considered representative of both the cp and b soil samples. next, when testing the normality of analysed variables in urban soil of the b group, a striking departure from the normality was discovered for cu (sw–w = 0.69, p<0.001), a mode rate one in case of al, k, cr, mn, as, and y, whereas the rest exhibit normal distribution (e.g. zn: sw–w = 0.94, p = 0.50). the non-normal distribution of cu is consistent with the results of the kruskal-wallis test, additionally underpinning the postulation that copper contamination occurs in the b soil group. concerning the cp group, the greatest departure from normality was again discoverd for cu (sw–w = 0.49, p<0.001), a moderate one in case of zn (sw–w = 0.82, p = 0.008), k, ca, mn, fe, pb, and ga, whereas the rest exhibit normal distribution. generally, this fi nding could be attributed mostly to natural geochemical processes commonly occurring in weathering profi les (loughnan, 1969), and to a lesser degree to the copper contamination which is mainly of anthropogenic origin (halamić et al., 2003). a similar conclusion could be drawn from the kendall’s tau correlation matrix calculated for the b and cp groups. the general assessment of its results is as follows (table 3): – the highest correlation (0.77) found for the al-rb pair in the cp group, defi ning the geogenic association, is statistically signifi cant, yet lower than the weakest (0.84) signifi cant correlation found for the k group (including the pairs al-loi, al-cu, and al-zn; see the text above); – correlations among the conservative components (al, fe, ni, and rb) are mostly low, non-signifi cant and even negative, showing relationships that cannot be explained by common geochemical processes in weathering profi les; table 2: basic statistical parameters (sd – standard deviation) of the measured variables (loi − loss on ignition) in three soil groups defi ned by sampling localities (k – check samples, number of samples 5; b – soil surrounding the b factory, number of samples 15; cp – soil surrounding the cp factory, number of samples 15). mean median min max sd k b cp k b cp k b cp k b cp k b cp cu (ppm) 34.60 92.05 54.17 34.8 65.8 41.2 30.7 37.3 33.2 37.7 331.8 186.7 2.75 75.63 40.45 zn (ppm) 146.00 161.61 160.77 145.0 156.7 156.6 135.3 129.2 132.7 162.1 213.9 224.3 9.87 23.88 21.50 pb (ppm) 24.80 22.48 22.75 24.1 22.2 22.2 22.3 15.3 14.3 30.1 30.3 43.8 3.19 4.03 6.92 as (ppm) 13.26 13.74 13.19 13.4 13.3 13.2 12.1 12.1 11.3 14.4 15.5 15.1 1.04 1.25 1.10 al (%) 13.86 14.07 13.78 13.9 13.7 13.9 13.4 12.1 11.8 14.2 15.8 15.2 0.29 0.94 0.80 k (%) 1.96 2.01 1.96 2.0 2.0 2.0 1.9 1.7 1.6 2.0 2.2 2.1 0.05 0.13 0.13 ca (%) 0.50 0.97 0.72 0.5 1.0 0.7 0.4 0.6 0.6 0.6 1.5 1.4 0.10 0.26 0.21 ti (ppm) 6453.04 6015.73 6097.66 6452.6 6033.9 6088.2 6386.8 5688.2 5803.4 6512.1 6208.0 6318.4 45.36 123.56 130.12 v (ppm) 164.20 155.70 157.69 162.1 153.9 157.4 156.0 139.5 147.3 172.9 170.6 169.2 7.12 9.47 5.54 cr (ppm) 152.36 160.95 149.26 151.5 160.3 150.2 144.7 145.9 129.2 161.7 192.9 172.3 7.22 10.76 12.71 mn (ppm) 791.26 857.29 895.46 834.1 825.1 875.0 601.0 757.8 756.2 1021.3 1025.9 1333.6 170.00 78.71 136.70 fe (%) 4.34 4.77 4.56 4.4 4.8 4.6 4.1 4.2 3.8 4.5 5.3 5.1 0.18 0.35 0.30 co (ppm) 16.56 18.18 17.23 16.7 18.2 17.4 15.6 16.1 14.9 17.1 19.6 19.2 0.56 1.10 0.99 ni (ppm) 70.70 75.32 73.76 70.8 76.3 72.0 66.7 67.9 67.7 76.0 84.8 82.8 3.93 4.55 4.34 ga (ppm) 24.48 22.07 22.83 24.3 21.8 23.1 23.5 18.6 18.5 25.5 25.9 25.0 0.78 1.77 1.59 rb (ppm) 157.26 145.34 146.16 156.9 144.3 147.5 148.0 123.6 116.5 170.4 160.4 165.7 8.61 10.05 11.97 sr (ppm) 130.66 132.37 135.99 131.0 132.1 136.7 128.8 123.2 129.4 131.7 138.2 141.3 1.20 4.27 3.33 y (ppm) 101.52 101.52 106.21 102.5 105.3 107.3 93.1 80.0 88.8 111.1 118.9 126.4 7.17 13.71 9.67 zr (ppm) 1044.26 832.51 914.93 1027.2 867.9 912.2 930.6 602.7 643.7 1207.0 1040.7 1360.9 103.19 145.09 171.55 loi (%) 7.98 6.05 6.54 8.1 6.0 6.2 7.2 4.2 3.8 8.5 7.4 8.9 0.51 1.06 1.64 geologia croatica 62/3geologia croatica 184 – with the exception of a signifi cant correlation between rb and zn (0.38) in the b group, all other correlations of either cu or zn with respect to the conservative elements are low, non-signifi cant and even negative, presumably due to processes other than geogenic ones (halamić et al., 2003); – a positive correlation between organic matter content and zn retention by soil (adriano, 1986) is confi rmed in this study since signifi cant loi-zn correlations are found for both soil groups (0.46 and 0.39, respectively). furthermore, it is of interest to note that cu shows no signifi cant correlation to loi as opposed to the fact that copper is one of metals exceptionally tightly bound by humates (salomons & förstner, 1984). trace metal correlations in the k group (table 1) are non-signifi cant, ranging from 0.00 to 0.60, whereas their values in the b and cp groups (table 3) are signifi cantly positive (the pairs cu-zn and cu-pb in particular), which would indicate an anthropogenic infl uence on the trace metal composition of the investigated urban soil (halamić et al., 2003). from this, it can be inferred that a considerable part of the enrichment of cu (table 2) in the b soil group (and partly in the cp group, too), as compared with the respective contents in the soils from northwestern croatia (halamić et al., 2003), is due to input from the b’s industrial emissions. halamić et al. (2003) found the cu content varying from 5 to 248 ppm, with the mean and median values of 25 and 22 ppm, respectively. similarly, adriano (1986) points out that the cu content of most soils generally falls in the 20 to 40 ppm range, and that soils derived from acid igneous rocks contain lower concentrations of cu than those developed from basic igneous rocks. in figure 3 concentrations of cu and zn have been plotted as a function of sampling localities. from this, it can be clearly seen that both variables show concordant patterns in the two sites that is in a reasonably good agreement with their correlations (table 3). with respect to fairly low and uniform cu and zn values in the cp group, there is a sharp increase in cu values at the sites cp13 (104.9 ppm) and cp14 (186.7 ppm) located near the fence surrounding the b factory (fig. 1). these results additionally confi rm that the copper contamination of the investigated urban soil is solely due to the b’s industrial activity. the next step to confi rm this is the leaching analysis. it is well known that the exchangeable phase represents the most mobile fraction of elements which is introduced by anthropogenic activities and bound to the sediment in adsorbed form (salomons & förstner, 1984). leaching analysis was carried out on several samples from both urban soil groups, selected according to their lowest and highest total cu values (fig. 3) in order to maximise the possible difference in trace metal leachate concentrations. figure 4 presents the data concerning the copper leachate levels measured in selected samples of the b soil group. it clearly shows that the patterns of the total cu, nh4oac-extractable cu and the percentage of cu constituting exchangeable phase are fairly similar; in other words, sampling localities with elevated total cu values contain much more bioavailable cu than those with background total cu levels. this fi nding is consistent with a highly signifi cant positive kendall’s tau correlation coeffi cient (>0.99) between the extracted and total cu levels in the b soil group. hereby, these data defi nitely confi rm strong human infl uence on soil composition in the vicinity of the b factory. referring to the cp group, leaching analysis of zn found a highly signifi cant negative correlation (>–0.99) between extracted and total zn values, suggesting that their origin would be geogenic. the kendall’s tau correlation coeffi cients calculated for extracted and total cu (the cp group) table 3: the kendall’s tau correlation matrix for the b and cp (in italics) soil groups (numbers in bold are signifi cant at p < 0.05; number of samples in each group is 15). al (%) fe (%) ni (ppm) rb (ppm) loi (%) cu (ppm) zn (ppm) pb (ppm) as (ppm) al (%) 1.00 1.00 fe (%) 0.59 0.62 1.00 1.00 ni (ppm) 0.13 –0.04 0.23 –0.16 1.00 1.00 rb (ppm) 0.73 0.77 0.66 0.70 0.17 0.08 1.00 1.00 loi (%) 0.33 0.03 0.19 0.31 –0.13 0.02 0.38 0.18 1.00 1.00 cu (ppm) 0.06 –0.09 –0.17 0.10 –0.29 0.29 0.00 0.09 0.27 0.30 1.00 1.00 zn (ppm) 0.27 –0.28 0.23 0.04 –0.10 0.06 0.38 –0.09 0.46 0.39 0.58 0.37 1.00 1.00 pb (ppm) –0.08 0.07 –0.17 0.19 –0.46 –0.15 –0.02 0.05 0.33 0.47 0.48 0.39 0.40 0.43 1.00 1.00 as (ppm) 0.44 0.22 0.24 0.41 –0.12 –0.08 0.50 0.18 0.66 0.26 0.25 0.38 0.33 0.34 0.35 0.48 1.00 1.00 figure 3: total cu and zn concentrations in the urban soil groups. medunić et al.: distribution of copper and zinc in the soil of an industrial zone in the city of garešnica, croatia geologia croatica 185 and zn (the b group) levels are irregular and insignifi cantly low. leaching analysis of the urban soil groups is strongly supported by xrd phase analysis (fig. 2) which shows no other mineral phases except those originating from surrounding parent rocks. these mineral phases, especially phyllosilicate phases related to clay minerals, together with organic matter are adsorbents for the amount of elements derived from human activity. finally, the variation of cu and zn content in the investigated urban soils was expressed as metal/aluminium ratios (förstner & wittmann, 1979; hanson et al., 1993; daskalakis & o’connor, 1995). förstner & wittmann (1979) emphasise that ‘the ratio of the element under consideration to another element of little variability, e.g., an element with ‘conservative behaviour’, represents the ‘sediment enrichment factor’. in other words, this factor, com monly called ‘enrichment factor’ (ef), is simply a way of quantifying the possible environmental impact. there are three categories of enrichment factors (golchert et al., 1991): ef≤2 mean no anthropogenic contribution, 2<ef<10 indicates a possible anthropogenic contribution, and ef≥10 clearly indicates an anthropogenic contribution. prohić et al. (1995) point out that ‘the choice of reference material and appropriate conservative element is crucial to the fi nal conclusions’. in this paper, a standard reference material is represented by the k soil group, the trace element content of which can be taken as background values. the choice of al as a reference element is based on the fact that it is often used as a normaliser of trace element data, due to its high natural abundance and because it is not associated with anthropogenic input (förstner & wittmann, 1979; prohić et al., 1995). linear regression analysis conducted for cu regarding the b and cp soil group’s shows that aluminium accounts for only 0.1% and 2% of the metal concentration variability, respectively. in the case of zn, respective results are also low, i.e. 16% and 6%. in contrast, al accounts for more than 80% of the cu and zn variability (r2 > 0.8) in the k soil group. the poor correlation of cu and zn with al in the b and cp groups is evidence for the anthropogenic contribution of these traces metals to the investigated urban soils (förstner & wittmann, 1979; prohić et al., 1995). in figure 5 enrichment factors of cu and zn have been plotted as a function of sampling localities. apart from their general similarity with total metal values (fig. 3), figure 5 suggests that approximately 40% of cu samples of the b group fall in the category 2<ef<10, whereas one sample shows ef=10. moreover, samples cp13 and cp14 also fall in the category 2<ef<10. therefore, it has been inferred on the basis of cu efs and the results of leaching analysis that cu concentrations in the urban soil groups are elevated above natural levels as a result of factory b’s industrial activity. 4. conclusions analytical results show that natural geochemical processes occurring in weathering profi les are largely responsible for the overall geochemical and mineralogical composition of the investigated soils, but activities of the chemical industry left their impact on the soil in the vicinity of factory b. in comparison with the background element composition of the control soils, the urban soil surrounding factory b shows elevated cu values as a consequence of anthropogenic activity. the kruskal-wallis test confi rmed this difference as statistically signifi cant at p<0.001. the cec values of the control soil samples are 16.1 meq/100g, and 4.6 meq/100g after the removal of organic matter. mineral composition of the all three soil groups is represented by quartz, plagioclase, chlorite, mica/illite and kaolinite. the observed mineral composition corresponds well to the measured cec value strongly suggesting the occurrence of phyllosilicate minerals with general cec values ranging from 5 to 25 meq/100g. it is inferred that a highly signifi cant positive kendall’s tau correlation coeffi cient (>0.99) between extracted and total cu levels in the b soil group confi rms the infl uence of factory b on the urban soil copper values. furthermore, the figure 4: the results of leaching analysis carried out on several samples of the b soil group (cuorig – cu total concentration in soil, cu (ppm) – cu concentration in leachates (exchangeable phase), cu (%) – percentage of cu constituting exchangeable phase). figure 5: enrichment factor values of cu and zn calculated for the b and cp soil groups. metal/alk = (conc. metalsample/alsample)/(metal(k soil)/al(k soil)). geologia croatica 62/3geologia croatica 186 kendall’s tau correlation coeffi cients between cu and the conservative elements are mostly low, non-signifi cant and even negative, showing relationships that cannot be expla ined by common geochemical processes in weathering profi les. data concerning cu enrichment factors show that approximately 40% of samples of the b group fall in the category 2<ef<10, whereas one sample shows ef=10. the cu content in the urban soil groups is found to be elevated above natural levels as a result of b’s industrial activity. acknowledgment the paper has benefi ted considerably from valuable comments on the original manuscript made by referiees dr. zoran peh and dr. enrico dinelli. references adriano, d.c. (1986): trace elements in the terrestrial environment.− springer-verlag, new york, berlin, heidelberg, tokyo, 533 p. ammann, l., bergaya, f. & lagaly, g. (2005): determination of the cation exchange capacity of clays with cooper complexes revisited.− clay min., 40, 441−453. doi: 10.1180/00098550540 40182 bertram, m., graedel, t.e., rechberger, h. & spatari, s. (2002): the contemporary european copper cycle: waste management subsystem.– ecol. econ., 42, 43–57. pii: s0921-8009(02) 00100-3 crnko, j. (1998): vodič geološke ekskurzije na moslavačku goru [croatian geological society excursion guide book for moslavačka gora – in croatian].– hrvatsko geološko društvo, zagreb, 85 p. daskalakis, k.d. & o’connor, t.p. (1995): normalization and elemental sediment contamination in the coastal united states.– env. sci. technol., 29/2, 470−477. doi: 10.1021/es00002a024 förstner, u. & wittmann, g.t.w. (1979): metal pollution in the aquatic environment.– springer-verlag, berlin, heidelberg, new york, 486 p. gleit, a. (1985): estimation for small normal data sets with detection limits.– environ. sci. technol., 19, 1201–1206. doi: 10.1021/es 00142a011 golchert, b., landsberger, s. & hopke, p.k. (1991): determination of heavy metals in the rock river (illinois) through the analysis of sediments.– j. radioan. nucl. ch.-ar., 148/2, 319−337. doi: 10.1007/bf02060365 graedel, t.e., bertram, m., fuse, k., gordon, r.b., lifset, r., rechberger, h. & spatari, s. (2002): the contemporary european copper cycle: the characterization of technological copper cycles.– ecol. econ., 42, 9–26. doi: 10.1016/s0921-8009(02) 00101-5 halamić, j., galović, l. & šparica, m. (2003): heavy metal (as, cd, cu, hg, pb and zn) distribution in topsoil developed on alluvial sediments of the drava and sava rivers in nw croatia.– geol. croat., 56/2, 215−232. hanson, p.j., evans, d.w., colby, d.r. & zdanowicz, v.s. (1993): assessment of elemental contamination in estuarine and coastal environments based on geochemical and statistical modeling of sediments.– marine environ. res., 36/4, 237−266. doi: 10.1016/ 0141-1136(93)90091-d hu, n., li, z., huang, p. & tao, c. (2006): distribution and mobility of metals in agricultural soils near a copper smelter in south china.– environ. geochem. hlth., 28, 19–26. doi: 10.1007/s10653005-9007-z jurak, v., pfaff, s., horvat, k. & krklec, n. (2006): provjera hipoteze o homogenosti geotehničkih sredina na lokaciji 'čađare' u kutini [verifi cation of the hypothesis regarding the homogeneity of geotechnical mediums at the 'soot factory / čađara' location in kutina – in croatian].– rudarsko-geološko-naftni zbornik, zagreb, 18, 29−41. korolija, b. & crnko, j. (1985): osnovna geološka karta sfrj 1:100000 list bjelovar, l 33−82 [basic geological map of sfry 1:100000, bjelovar sheet – in croatian].– geološki zavod zagreb, savezni geološki zavod, beograd. korolija, b., vragović, m., crnko, j. & mamužić, p. (1986): osnovna geološka karta sfrj 1:100000. tumač za list bjelovar l 33−82 [basic geological map of sfry 1:100000, geology of the bjelovar sheet – in croatian].– geološki zavod zagreb, savezni geološki zavod, beograd, 45 p. kovačić, m. & grizelj, a. (2006): provenance of the upper miocene clastic material in the southwestern part of the pannonian basin.– geol. carpat., 57, 495−510. kuo, s., heilman, p.e. & baker, a.s. (1983): distribution and forms of copper, zinc, iron, and manganese in soils near a copper smelter.− soil sci., 135, 101−109. li, j., xie, z.m., xu, j.m. & sun, y.f. (2006): risk assessment for safety of soils and vegetables around a lead/zinc mine.– environ. geochem. hlth., 28, 37−44. doi: 10.1007/s10653-005-9009-x li, x. & thornton, i. (2001): chemical partitioning of trace and major elements in soils contaminated by mining and smelting activities.− applied geochem., 16, 1693−1706. doi: 10.1016/s08832927 (01)00065-8 loughnan, f.c. (1969): chemical weathering of the silicate minerals.– american elsevier publishing company, new york, 154 p. macklin, m.g. (1992): metal contaminated soils and sediment: a geographical perspective.– in: newson, m.d. (ed.): managing the human impact on the natural environment: patterns and processes. belhaven press, london, 172−195. martley, e., gulson, b., louie, h., wu, m. & di, p. (2004): metal partitioning in soil profi les in the vicinity of an industrial complex, new south wales, australia.− geochem.: explor. env., a4, 171−179. doi: 10.1144/1467-7873/03-030 matschullat, j., ottenstein, r. & reimann, c. (2000): geochemical background – can we calculate it?– environ. geol., 39/9, 990–1000. doi: 10.1007/s002549900084 merrington, g. & alloway, b.j. (1994): the fl ux of cd, cu, pb and zn in mining polluted soils.− water air soil poll., 73, 333−344. doi: 10.1007/bf00477997 miko, s., halamić, j., peh, z. & galović, l. (2001): geochemical baseline mapping of soils developed on diverse bedrock from two regions in croatia.– geol. croat., 54/1, 53−118. oreščanin, v., katunar, a., kutle, a. & valković, v. (2003): heavy metals in soil, grape, and wine.– j. trace microprobe t., 21, 171–180. doi: 10.1081/tma-120017912 prohić, e., miko, s. & peh, z. (1995): normalization and trace element contamination of soils in a karstic polje – an example from the sinjsko polje, croatia.– geol. croat., 48/1, 67−86. reimann, c. & filzmoser, p. (2000): normal and lognormal data distribution in geochemistry: death of a myth. consequences for the statistical treatment of geochemical and environmental data.– environ. geol., 39/9, 1001–1014. doi: 10.1007/s002549900081 reimann, c., filzmoser, p. & garrett, r.g. (2005): background and threshold: critical comparison of methods of determination.– sci. tot. env., 346, 1−16. doi: 10.1016/j.scitotenv.2004. 11.023 reimann, c. & garrett, r.g. (2005): geochemical background – concept and reality.– sci. tot. env., 350, 12–27. doi: 10.1016/j. scitotenv.2005.01.047 medunić et al.: distribution of copper and zinc in the soil of an industrial zone in the city of garešnica, croatia geologia croatica 187 salomons, w. & förstner, u. (1984): metals in the hydrocycle.– springer-verlag., berlin-heidelberg, 349 p. spatari, s., bertram, m., fuse, k., graedel, t.e. & rechberger, h. (2002): the contemporary european copper cycle: 1 year stocks and fl ows.– ecol. econ., 42, 27−42. doi: 10.1016/s0921 8009(02)00103-9 škorić, a. (1986): postanak, razvoj i sistematika tla [genesis, development, and systematics of soils − in croatian].– fakultet poljoprivrednih znanosti sveučilišta u zagrebu, zagreb, 172 p. špoljar, a. (1999): fao klasifi kacija s bazom podataka za pedološku kartu republike hrvatske sitnog mjerila [fao classifi cation with database of pedologic map of croatia in small scale − in croatian].– unpubl. msc. thesis, university of zagreb, 75 p. thornton, i. (1990): soil contamination in urban areas.– palaeogeogr. palaeoclimatol. palaeoecol., 82, 121−140. van olphen, h. & fripiat, j.j. (1979): data handbook for clay materials and other non-metallic minerals.– pergamon press, oxford, 346 p. warren, r.s. & birch, p. (1987): heavy metal levels in atmospheric particles, roadside dust and soil along a major urban highway.– sci. total. environ., 59, 253–256. doi: 10.1016/0048-9697(87) 90446-3 yong, r.n. & warkentin, b.p. (1975): soil properties and behaviour.– elsevier, amsterdam, 449 p. manuscript received april 06, 2009 revised manuscript accepted july 03, 2009 available online october 02, 2009 available online ??????????? 1. introduction study of the pannonian sediments in the southwestern part of the medvednica mts. (fig. 1) and their relationship with underlying sarmatian deposits, revealed two entirely new forms of the genus c o n g e r i a . gorjanovi∆-kramberger (1890) noticed and briefly described a new congerian form from the “praepontian white marls” from the vrapëe locality, but he did not establish and name a new species, because of the small number of specimens and their poor preservation. during this study, a collection of approximately 20 specimens of this form has enabled the establishment of a new species, congeria baschi n.sp., which can be clearly identified and positioned in a stratigraphically narrow interval. the presumption has been made, that c . b a s c h i n.sp. represents the ancestral form of the forthcoming radiation of congerian species (see fig. 10). sremac (1981) described c. vugroveci as a new species from the upper pannonian marls of vugrovec in the southeastern part of the medvednica mts. (northnew congerian species and their similarity with congeria banatica from the pannonian sediments in northern croatia davor vrsaljko 1 and jasenka sremac 2 ern croatia), distinguishing it from the previously known c. banatica hörnes. several specimens have been collected during this study, thus confirming the validity of c. vugroveci. previous authors dealing with c. bana t i c a (hörnes, 1875; kochansky-devidé, 1976; sremac, 1981; vrsaljko, 1997) noticed the variability of this form and its separation into three main morphological varieties. in this study, we will discuss this variability and use the biometrical statistics (see fig. 8) to describe one of these forms as the entirely new species, congeria susedana n.sp. andrusov (1964) described congerian taxa belonging to the group s u b g l o b o s a e as “indicative of calm and sheltered, oligohaline lacustrine palaeoenvironments”, stratigraphically positioned within the pannonian stage. according to the morphology of the shell, the new species described in this paper could belong to the subglobosae. the term “group”, although not found in the iczn (international codex of zoological nomenclature), has been applied to congerian bivalves by many authors since andrusov (1964), in order to express the typical morphotypes. there have been several attempts to equate congerian “groups” with legal taxonomical categories (e.g. genus, subgenus), but the collected fossil material is rarely preserved well enough to enable this task. populations of congeria baschi n.sp. can commonly be found in the lower pannonian limestones and marls (fig. 3) which were deposited in an almost freshwater (vrsaljko, 1997), shallow lacustrine palaeoenvironment. from the same horizon, a rich molluscan community has been collected including: radix (radix) croati ca (gorjanovi∆), r. (r. ) extensa ( g o r j a n o v i ∆ ) , gyraulus (g y r a u l u s) p r a e p o n t i c u s ( g o r j a n o v i ∆ ) , orygoceras laevis gorjanovi∆, limnocardium pra eponticum ( g o r j a n o v i ∆ ), l. spinosum ( l ö r e nthey). l. plicataeformis (gorjanovi∆) and others. an associated ostracod assemblage from the same horizons contains hungarocypris auriculata ( r e u s s ) , a m plocypris abscisa (reuss), candona (pontoniella) croatica s o k a » , c. (t h a m i n o c y p r i s) hodonensis p okorny and others. in the uppermost sections of the upper pannonian marls, rare specimens of congeria susedana n.sp. have been found (fig. 4). these marls were deposited in the relatively deep, distal parts of the lake (vrsaljko, g eol. c roat. 52/2 99 108 10 figs. 1 pl. zagreb 1999 key words: pannonian lake, miocene, pannonian basin, nw croatia, congeria , bivalvia, new species, endemic evolution. 1 institute of geology, sachsova 2, hr-10000 zagreb, croatia. 2 department of geology and palaeontology, faculty of science, university of zagreb, ul. kralja zvonimira 8, hr-10000 zagreb, croatia. abstract congeria baschi n.sp. and congeria susedana n.sp. are two new species from the pannonian sediments of the medvednica mts. (nw croatia). c. baschi n. s p . was found in the lower pannonian limestones, and c. susedana n.s p . was collected from the upper pannonian marls. relationships with the affiliated taxa enable reconstruction of a phyletic lineage beginning with congeria soceni jekelius, through c. baschi n.sp. to congeria banatica hörnes. c. banatica is the ancestor of two branches, leading to c. susedana n. sp. and c. vugro veci sremac, respectively. dreissenomya digitifera (andrusov) is the probable descendant of c. vugroveci. the accompanying assemblages of fossil molluscs and ostracods from the same horizons facilitate the precise stratigraphic and palaeoenvironmental positioning of the new taxa. 100 geologia croatica 52/2 1997). among the accompanying molluscs, the most important taxa are: gyraulus (g. ) tenuistriatus ( g o rjanovi∆), limnocardium winkleri ( h a l a v a t s ) , paradacna syrmiense (hörnes), ?cerastoderma mar garitacea (brusina), and ?c. protracta (gorjanovi∆). among the numerous ostracods, the following taxa are extremely abundant: hungarocypris hierogly phica (mehes), amplocypris dorsobrevis s o k a » , cypria dorsoconcava krsti∆, candona (p o n t o n i e l l a ) sagittosa krsti∆ and c. (l i n e o c y p r i s) pupini k r sti∆. 2. material and methods numerous specimens of d r e i s s e n i d a e mussels were collected during facies research of neogene sediments of mt. medvednica (nw croatia). several pannonian localities were investigated, including vrapëe and podsused in sw medvednica mt., where detailed stratigraphical columns were reconstructed (figs. 1, 3 and 4). previously collected pannonian congerian specimens from the croatian museum of natural history (gorjanovi∆, 1890) and faculty of science in zagreb (sremac, 1981), as well as the sketches published by hörnes (1875) were taken into consideration. shells of the available fossils were measured with calipers (20 specimens of c. banatica , 17 specimens of c. baschi n.sp., 6 specimens of c. susedana n.sp. and 5 specimens of c. vugroveci). specimens published by hörnes were measured from sketches. angles were also measured from shells or from sketches, but only on completely preserved specimens. the shell material is, unfortunatelly, poorly preserved. impressions and moulds are more common than fig. 1 location map: a) podsused; b) bolfani; c) vrapëe; d) medvedski breg; e) vugrovec; f) goranec; g) moravëe; h) koroviê; i) banovina region. fig. 2 schematic sketch of the morphometric shell elements in the genus c o n g e r i a : h) height; l) length; c) convexity; dl) length of the dorsal edge; k (h/l) elongation rate; α) angle between the ventral and the dorsal edge; β) angle between the dorsal and the anal edge; γ) angle between the dorsal edge and the border of the pseudolunular field; 1) beak; 2) main ridge; 3) ventral field; 4) dorsal field; 5) wing shaped extension; 6) mould of the ligament lamella; 7) pseudolunular field; 8) secondary ridge; 9) growth lines. complete shells. therefore most of the conclusions were based on the external shell morphology. a disperse diagram for c. banatica and c. susedana n.sp. considering height/length ratio versus the length of the dorsal edge was prepared. biometry in this case was just an auxiliary method, because the number of specimens (except for c. banatica ) was too small for the relevant statistical conclusions to be drawn. 3. taxonomy class bivalvia subclass heterodonta neumayr 1884 order veneroida adams & adams 1856 family dreisseniidae gray & turton 1840 genus congeria partsch 1835 (group subglobosae andrusov 1897) congeria baschi n.sp. (pl. i, fig. 1) 1890. congeria sp. gorjanovi∆-kramberger; gorjanovi∆-kramberger, p. 163, pl. 6, fig. 21. 1964. congeria sp. gorjanovi∆-kramberger; andrusov, p. 425, pl. 1, fig. 20. 101vrsaljko & sremac: new congerian species and their similarity with congeria banatica ... fig. 3 vrapëe type locality of congeria baschi n. sp. lithological column (for legend see fig. 10): 2) sand; 3) marl; 4) clay; 5) limestone. 1997. congeria sp. gorjanovi∆-kramberger; vrsaljko, p. 40, type 8. holotype (fig. 5 1*) is stored in the department of geology and palaeontology of the croatian museum of natural history in zagreb (inventory no. 290). it was found at vrapëe locality, in the southwestern part of medvednica mts., and was presented by gorjanovi∆-kramberger (1890; p. 163, pl. 6, fig. 21). gorjanovi∆-kramberger (1890) was the first to find two specimens in the “praepontian” (= lower pannonian) marls from the surroundings of vrapëe village in the medvednica mts. he determined them as belonging to the genus c o n g e r i a , offering a short description of the smaller specimen: “specimen is 8.5 mm long, and 5 mm wide, triangular in outline. posterior edge is slightly extended, ridge is blunt, and the beak is weakly pointed out and incurved”. the same author furthermore claimed that, due to the small number of specimens and their poor preservation, which made the reconstruction of the shell impossible, he could not offer a more detailed description, and determined this form to be only congeria sp. after collecting twenty new specimens, we can conclude that this small congerian taxon always appears within the radix croatica zone. due to its morphological features it deserves to be described in detail, and acquire the status of a new species. 102 geologia croatica 52/2 derivatio nominis: the species is dedicated to the well known croatian palaeontologist oto basch, employed in the institute of geology in zagreb, who, with his encyclopedic knowledge, strongly influences the education of young geologists, and makes significant contributions to croatian geology with his published papers. locus typicus: specimens no. 1 and 2 have been collected near vrapëe village in the western part of the medvednica mts., at the same locality which was first studied by gorjanoviê-kramberger (holotype 1*), and consists of thin-bedded limestones (ca. 20 cm), inmediately above the sarmatian/pannonian boundary (fig. 3). most of the other specimens have been also found in the vicinity of vrapëe village, and several of them were collected in the banovina district. stratum typicum: lower pannonian, radix croati ca zone. diagnosis: very small, in most cases triangular, significantly convex shell. outer shell surface with primary ridge close to the anterior field, and extremely weak secondary ridge close to the posterior field. posterior field with weakly pronounced wing-shaped extension. description: small-sized, rather convex shell, triangular in outline, with clearly developed growth lines and indistinct wing-shaped extension on the posterior fig. 5 specimens of congeria baschi n.sp. from the vrapëe locality: 15) adult form; 1) juvenile specimen; 1*) holotype from gorjanovi∆-kramberger (1890).15 1 1* fig. 4 podsused type locality of c o n g e ria susedana n. sp. lithological column: 1) gravel; 3) marl; 4) clay; 5) limestone. 103vrsaljko & sremac: new congerian species and their similarity with congeria banatica ... field, which becomes well developed in older specimens. no specimen with preserved shell material has been found. imprint of the ligament lamella, extending along the dorsal edge, almost half of its length, can often be observed. umbo small, sharp, slightly incurved forward. the median, most convex part of the shell, bears two ridges. main (primary) ridge is well developed, situated closer to the anterior field, straight to slightly incurved, and rounded in cross section. secondary ridge is situated at the posterior field, it is more rounded, and is particularly well-developed in younger specimens. elongation rate (k), defined in fig. 2, is almost constantly 1.5. the sum of the angles between the dorsal edge and the edge of the anterior field (α) and the angle between the dorsal edge and the edge of the posterior field (β) is almost always 180° (see fig. 2). in adult shells, due to the weak winglike extension, this angle decreases in value by ca. 10 degrees. dimensions: spec. h l dl c α β k locality (mm) (mm) (mm) (mm) (°) (°) 1* 8.5 5.0 4.0 2 60 120 1.7 vrapëe 1 3.0 2.0 1.5 1 50 130 1.5 vrapëe 2 3.0 2.0 1.5 1 50 130 1.5 vrapëe 3 3.0 2.0 1.5 bolfani 4 7.0 4.5 1.5 banovina 5 9.0 5.5 5.0 2 60 120 1.6 bolfani 6 5.0 3.0 1.6 banovina 7 5.0 3.0 1.6 vrapëe 8 7.0 4.5 1.5 vrapëe 9 8.0 5.0 1.6 vrapëe 10 8.0 5.0 1.6 vrapëe 11 6.5 4.0 1.6 vrapëe 12 9.0 5.5 1.6 vrapëe 13 4.0 2.5 1.6 vrapëe 14 8.0 5.0 1.6 vrapëe 15 7.5 4.5 4 2 60 120 1.5 vrapëe 16 12.0 7.5 1.6 banovina 17 4.5 3.0 1.5 banovina comparison: congeria baschi n. sp. strongly resembles c. neumayri andrusov (ranging from the “helvetian” to the pliocene) in its shape, and the position of the main ridge. andrusov (1964) reports the presence of typical specimens from the marine miocene at the laa locality (of karpatian age), and papp (1954) considers c. neumayri to be persistent in a wide salinity range. according to its main features, c. baschi strongly resembles c. jadrovi brusina, from the lower pliocene freshwater sediments of sinjsko polje, although. andrusov (1964) related c. neumayri and c . j a d r o v i with the group m y t i l i f o r m e s, thus making a comparison with c. baschi n.sp. barely possible. it is more probable to presume the origin of c. baschi f r o m similar older sarmatian taxa, such as c. soceni j e k elius and/or c. moesia jekelius, scarce brackish representatives of the group subglobosae. papp (1954) collected and described these taxa from the sarmatian and the pannonian (zones a and b) of the vienna basin. congeria banatica hörnes (pl. 1, fig. 2) 1 8 7 5 . congeria banatica nov.sp.; hörnes, p. 75, pl. 3, figs. 3-5. 1 9 6 4 . congeria banatica hörnes; andrusov, p. 132-133, pl. 11, figs. 18-20. 1990. congeria banatica hörnes; vrsaljko, p. 38, type 1. short description: adult form type a(hörnes, 1875; pl. 3, fig. 3) small-sized shell, rather convex, elongate-trapezoidal in outline. shell material usually not preserved. well exposed, dense growth lines; impression of the ligament lamella following the dorsal edge, almost half of its length. posterior field with small wing-shaped extension. ridge well-defined, sharp in the umbonal portion, becoming string-like in adult specimens, slightly rounded, slightly incurved towards the anterior field. umbo small, weak, incurved forward. juvenile form type b(hörnes, 1875; pl. 3, fig. 2) shell smaller and less convex than in the a-type. numerous, weaker growth lines. trapezoidal outline, without the winglike extension. ridge well defined, sharp, string-like, rounded only in the youngest portion of the shell, incurved as the elongate “s” and dislocated towards the anterior portion. umbo weak, sharper than in a-type, and incurved forwards. adult form type c(vrsaljko, 1997; p. 38, type 1) similar to type a, but shell more elongate and more convex. elongate-trapezoidal in outline. ridge situated almost in the middle of the outer shell. common features: younger specimens possess well-developed and sharp ridge, while the adult shells bear string-like ridges and wing shaped extensions at the posterior field. dimensions: spec. h l dl c α β k locality (mm) (mm) (mm) (mm) (°) (°) from hörnes (1875) type a 17 16 13 ? 70 110 1.0 banat type b 13 9 9 ? 70 120 1.4 banat this study 1 16 13 13 2.0 70 100 1.1 medv.breg 2 18 12 10 3.0 80 130 1.5 moravëe 3 21 18 14 2.0 70 110 1.1 koroviê 4 19 14 12 3.0 80 120 1.2 podsused 5 20 15 12 3.0 80 120 1.3 podsused 6 18 15 12 3.0 90 120 1.2 podsused 7 18 13 12 3.0 80 110 1.3 podsused 8 14 10 8 1.5 80 120 1.4 podsused 104 geologia croatica 52/2 9 15 10 9 1.5 70 120 1.5 podsused 10 12 9 8 2.0 70 120 1.3 podsused 11 15 10 9 3.0 80 120 1.5 goranec 12 16 11 9 2.5 90 120 1.4 goranec 13 17 12 8 2.5 70 110 1.4 vugrovec 14 15 11 8 2.0 80 110 1.3 vugrovec 15 22 18 12 3.0 70 130 1.2 banovina 16 21 18 12 2.5 70 130 1.1 banovina 17 18 15 12 3.0 90 130 1.2 banovina 18 20 16 13 3.0 80 110 1.2 banovina 19 21 17 13 2.5 70 110 1.2 banovina 20 22 19 14 3.0 70 100 1.1 banovina congeria susedana n.sp. (pl. 1, fig. 4) 1997. congeria aff. banatica hörnes; vrsaljko, p. 38, type 2. derivatio nominis: species has been named after the famous historic fortress susedgrad, near which the abandoned quarry of cement marls with most of the described specimens is located. holotypus: specimen no. 1. locus typicus: podsused, western part of zagreb, widely exposed profile of marly sediments near the former cement factory (fig. 4). stratum typicum: upper pannonian; uppermost part of deepwater lacustrine marls, in the c o n g e r i a banatica zone. d i a g n o s i s : very small, rather convex shell, trapezoidal in outline, with wide dorsal field and distinct wing shaped extension. description: small-sized shell, prominently convex, trapezoidal in outline, with distinct, closely-spaced growth lines and well-developed wing shaped extension at posterior field. in most cases a thin calcite shell layer is preserved. cast of the ligament lamella along the dorsal edge is well developed and extends over half its length. umbo small, sharp and weakly incurved forward. almost in the middle of the outer shell, a distinct ridge can be observed, rather sharp near the umbo, and weakly rounded and arcuate forward at the front. adult specimens are slightly more elongate. dimensions: spec. h l dl c α β k locality (mm) (mm) (mm) (mm) (°) (°) 1 11 12 10 2 80 120 0.9 podsused 2 9 10 7 2 80 120 0.9 podsused 3 10 11 8 3 80 120 0.9 podsused 4 11 10 7 3 80 120 1.1 podsused 5 12 11 8 2 80 120 1.1 medv.breg 6 12 11 8 2 80 120 1.1 medv.breg c o m p a r i s o n : congeria susedana n. sp. strongly resembles c. banatica hörnes in shape and ridge position, but the difference appears in the decreased size of the shell, arcuate ridge and longer mould of the ligament lamella. according to its appearance in similar facies and somewhat younger horizons, a narrow link of the new species with c. banatica is proposed (see fig. 10). some similarities in size and outline with c. vugro veci sremac can be observed, but the latter is characterised by the appearance of the pseudolunular field. many previous authors considered c. susedana t o be a variety of c. banatica , but, according to the pronounced biometric difference this form deserves to be established as a new palaeontological species. congeria vugroveci sremac 1981. congeria vugroveci n.sp.; sremac, p. 109, pl. 1, figs. 1-4. fig. 6 specimens of c. banatica hörnes (hörnes, 1875): type a adult specimen, from the banat district and type b juvenile form, from the banat district; 7) adult specimen from podsused. type a type b 7 105vrsaljko & sremac: new congerian species and their similarity with congeria banatica ... short description: shell small-sized, rather inflated, trapezoidal in outline, with distinct, closely spaced growth lines. mould of the ligament lamella can often be observed along the entire dorsal edge. imprint of the posterior lamella extends almost half the length of the dorsal edge, and the anterior mould is weakly developed and very short. at the anterior side a weak ridge can be observed, thus producing a small pseudolunular field. ridge is distinct, sharp and very slightly incurved in shape of the elongate “s” form, dividing the outer shell surface into two almost equal portions. umbo is weak, rather wide, blunt, and very slightly incurved toward the anterior portion of the shell. dimensions: spec. h l dl c α β γ k locality (mm) (mm) (mm) (mm) (°) (°) (°) 1 6.5 6 5 1.0 60 100 120 1.0 med.breg 2 8.0 6 1.2 med.breg 3 7.0 5 1.2 med.breg 4 14 13 12 2.0 70 110 110 1.0 goranec holotype 1* 8 9 8 1.5 75 105 130 0.9 vugrovec according to the development of the anterior margin and the appearance of the pseudolunular field, this form can be closely related to the genus d r e i s s e n o m y a (fuchs, 1870 from basch & æagar-saka», 1992). considering the similarity and its appearance in older sediments (upper pannonian), c. vugroveci could be the possible ancestral form for some younger pontian species, such as dreissenomya digitifera a n d r usov. 4. discussion and conclusions in this paper two new species of congerians from the pannonian marls from northern croatia, c o n g e r i a baschi n. sp. and c. susedana n. sp. are described and figured (figs. 5 and 7; pl. i, figs. 1, 3, 4 and 5). for congeria vugroveci sremac (fig. 9) a partial revision and completion of the description has been made. reconsidering the variability of c. banatica h ö rnes, as noticed by most of the previous authors, a reconstruction of the types of hörnes (1875; pl. 3, figs. 2 and 3) is offered and compared with our specimens (fig. 6; pl. i, figs. 2 and 6). we have found that c. banatica is a variable form, but c. susedana n. s p . described here can hardly be considered just a variety of c. banatica due to the completely different morphometrical features of the shell. according to the rather short stratigraphic range of c. banatica , as well as its constant palaeoenvironmental characteristics, it is hard to envisage considerable variability. studying the 20 specimens of c. banatica collected during our research a common feature can be observed. the ridge of the younger specimens is sharper and distinct, while in adult shells it becomes rounded, and the posterior field extends into a wing-shaped form. the elongation rate in adult shells is decreasing. fig. 8 scatter plot showing the relationship between the elongation rate (k) and the length of the dorsal edge (dl). fig. 7 specimen of the congeria susedana n.sp.; reconstruction of the holotype. 106 geologia croatica 52/2 special attention has been paid to the c. banatica hörnes, and its relationship with c. vugroveci s r emac and c. susedana n.sp. these two species are the possible descendents of c. banatica . for the early pannonian c. baschi n.sp. there are indications that it originates from some similar sarmatian brackish forms, introduced by papp (1954). this small species from the lowermost pannonian beds is almost the unique representative of c o n g e r i a (in lacustrine sediments) and, knowing that most congerian species appear first in the late pannonian substage, it could be considered one of the possible ancestral forms for the later explosion and divergence of the species (fig. 10). the main ecological factor influencing the variability of brackish and freshwater faunas, including congerians, is geographical isolation and decrease of salinity. the diversification of congerian taxa into the groups (sensu andrusov, 1964) obviously needs critical revision based on morphological features and new palaeoenvironmental data (i. magyar, personal communication). such revision would provide better foundation for the reconstruction of phylogenetic relationships within the family dreissenidae . studying the associated assemblage of fossil molluscs and ostracods from the same horizons, newly established congerian forms can be placed in the previplate i 1 and 3 congeria baschi n.sp., early pannonian, from the vrapëe locality; 1) x10, 3) x2. 2 and 6 congeria banatica hörnes, late pannonian, from the podsused locality; 2) x6, 6) x4. 4 and 5 congeria susedana n.sp., late pannonian, from the podsused locality; 4) x6, 5) x4. fig. 9 specimens of congeria vugroveci sremac: 1) juvenile form from medvedski breg; 1*) adult specimen, reconstruction of the holotype. 1 1* fig. 10 stratigraphic range and the suggested relationship among the congerian species. 107vrsaljko & sremac plate i 108 geologia croatica 52/2 ously defined biostratigraphic zones for the pannonian stage. so congeria baschi n.sp. belongs to the b (?ab) zone according to papp (1953), or β ( ?α) phase (according to soka», 1972), and c. susedana n. s p . the d zone or ?δ phase. acknowledgements most of the fossil molluscs were collected during the year 1993, within the project “facies and physical features of the neogene carbonate sediments”, when, at the suggestion of the project manager m. pikija the idea for this research was born. we thank k. ©iki∆ for the fossil material from the wider area of banovina. determination of ostracods has been performed by mrs. valentina hajek-tadesse. we express our gratitude to mrs. zlata juri©i∆-pol©ak from the croatian museum of natural history who allowed us to reconsider the type congerian specimens from the gorjanoviê collection. 5. references andrusov, n. (1964): fossil and living d r e i s s e n i dae from europe and asia.izbrannije trudi, 3, collected works (reprint edition), 1-404, moskva. basch, o. & æagar-saka», a. (1992): pontian dreissenidae (m o l l u s c a, l a m e l l i b r a n c h i a t a ) f r o m croatia.acta geologica, 22/1, 31-60, zagreb. gorjanovi∆-kramberger, d. (1890): die fauna der praepontischen bildungen von vrabëe.glasnik hrv. narav. druπtva, 5, 154-163, zagreb. hörnes, r. (1875): tertiär-studien (vi).jahrbuch geol. reichsanst., 25/1, 63-87, wien. kochansky-devidé, v. (1976): über die wiederholung gleichartiger formen in der entwicklungsgesichte der organismen, mit besonderer berücksichtigung der congerien (bivalvia).geol. vjesnik, 29, 75-89. papp, a. (1953): die molluskenfauna des pannon im wiener becken.mitt. geol. ges., 44, 85-222, wien. papp, a. (1954): die molluskenfauna im sarmat des wiener beckens.mitt. geol. ges., 45, 63-68, wien. soka», a. (1972): pannonian and pontian ostracod fauna of mt. medvednica.palaeont. jugosl., 11, 1140, zagreb. sremac, j. (1981): some new and less known species of molluscs of the croatica -beds and banatica-beds in northern croatia.geol. vjesnik, 33, 107-121. vrsaljko, d. (1997): pannonian stratigraphy in the southwestern part of the medvednica mt.unpublished m.sc. thesis, university of zagreb, 80 p. manuscript received september 20, 1999. revised manuscript accepted november 12, 1999. 05 malvic.indd 37 � 1. introduction geos ta tis ti cs is a we ll-es tab lis hed tool in dif fe re nt geos ciences, pri ma ri ly de fi ned as ad van ced in ter po la tion al go rit hms. in mo st ca ses, geos ta tis ti cal met ho ds of fer se ve ral ad van ta ges com pa red to other mat he ma ti cal ly sim pler in ter po la tion tec hniques. the mo st im por ta nt ad van ta ge of geos ta tis ti cs is the va riog ram fun ction it se lf. the re are se ve ral spa tial in ter pola tion met ho ds that ha ve the abi li ty of gi vi ng weig hts to da ta poin ts ac cor di ng to their re la ti ve po si tion to the lo ca tion to be es ti ma ted. howe ver kri gi ng is the on ly met hod that can ta ke in to con si de ra tion the spa tial ani sot ro py of the pa ra me te rs bei ng es ti ma ted throu gh the ani sot ro py of di rec tion va riogram, and, what is mo re, wit hout the va riog ram it wou ld be near ly im pos sib le to es ti ma te a geo lo gi cal at tri bu te whi ch does not ha ve fi ni te va rian ce li ke frac tu re po ro si ty (jános gei ger, per so nal com mu ni ca tion, 2007). mo reo ver, the va riog ram as a ba sic geos ta tis ti cal te rm forces ac cu ra te de ter mi na tion of spa tial re la tion shi ps amo ng har d-da ta. of cour se, it is not a ma gic tool, but an expe rien ced geo lo gi st can ve ry pre ci se ly de fi ne the weig hti ng coef fi cien ts be tween ha r d-da ta and their in fl uen ce at the new es ti ma tion poi nt. the geos ta tis ti cal idea was mos tly de ve lo ped in de pen dently of ma jor ac hie ve men ts in the fi e ld of spa tial sta tis ti cs. the wor ld-re nowned pio neer wo rk was do ne by krige (1951). the fi r st wi de ly known re sul ts are tho se in the wor ks of mathéron (e.g. mathéron 1962, 1963, 1965). the se in clu ded de tai led expla na tio ns of the kri gi ng, as a ba sic geos ta tis ti cal to mis lav malvić1 ab stra ct the data pre sen ted he re for the fi r st ti me in the croa tian geo mat he ma ti cal com mu ni ty, ai m to es tab li sh se ve ral cri teria whi ch wi ll aid in the se lec tion of de ter mi nis tic or stoc has tic geos ta tis ti cal met ho ds of es ti ma tion. this re view as so cia tes the theo re ti cal bac kgrou nd of kri gi ng, cok ri gi ng or stoc has tic si mu la tio ns wi th so me re sul ts ob tai ned by map pi ng ba de nian clas tic re ser voi rs in the dra va dep res sion. the se lec ted re ser voi rs are lo ca ted in the sta ri gra da c-bar cs nyu gat fi e ld, in the wes te rn pa rt of the dra va dep res sion, and at the be ni čan ci fi e ld in the easte rn pa rt of this dep res sion. bo th da ta se ts (ea ch wi th 14 poin ts) in clu de mean po ro si ty va lues ta ken from we ll log ana lysis in the re ser voir in ter val at the we ll si tes. this re sul ted in sig ni fi ca nt un cer tain ties in the va riog ram mo de ls, es pe cial ly wi th the de termi na tion of ran ge (at the se con da ry va riog ram axis). the cri ti cal ad van ta ge was the avai la bi li ty of a seis mic at tri bu te that cou ld be used as a se con da ry and co-regio na li zed va riab le (po ro si ty is the pri ma ry va riab le). in the fi r st exam ple (the be ni čan ci fi e ld) the seis mic at tri bu te was cor re la ted wi th the ave ra ge log ged po ro si ties. this ma de it pos sib le to ap ply the cok ri gi ng met hod as the be st in ter po la tion op tion. the cro ss-va li da tion re su lt was 2.19 for 14 wel ls. in con tra st, the exis ten ce of on ly a pri ma ry va riab le at the sta ri gra da c – bar cs nyu gat fi e ld, for ced the ap plica tion of stoc has tic si mu la tio ns as the bet ter es ti ma tion tool, whi ch can bet ter des cri be the po ro si ty chan ges in in te rwe ll areas. keywor ds: krigi ng, cok ri gi ng, gaus sian si mu la tio ns, po ro si ty, be ni čan ci fi e ld, sta ri gra da c – bar cs nyu gat fi e ld, badenian, dra va dep res sion, croatia 1 re ser voir en gi nee ri ng & fie ld de ve lop me nt, ina-oil in dus try plc., zag reb, croa tia (to mis lav.malvic@ina.hr) kri gi ng, cok ri gi ng or stoc has ti cal si mu la tio ns, and the choi ce be tween de ter mi nis tic or sequen tial ap proac hes geologia croatica 61/1 37–47 7 figs. 0 tabs. zagreb 2008 geologia croaticageologia croatica � 05 malvic.indd 3705 malvic.indd 37 24.6.2008 11:10:1724.6.2008 11:10:17 geologia croatica geologia croatica 61/1 38 tec hnique equi va le nt to the met hod of mean squa res ap plied in a li near gaus sian mo del. the se pa pe rs we re fol lowed by ma ny ot he rs from geos ta tis ti cal exper ts that im pro ved theory and prac ti ce of dif fe re nt geos ta tis ti cal met ho ds. a ve ry fa mous book was writ ten by journel & hujibregts (1978). andre jour nel was mat he ron’s stu de nt and he es tab lis hed geos tatis ti cal cour ses at stan fo rd uni ver si ty. mo reo ver, ripley (1981) showed the li nk be tween the mean squa res met hod and the li near gaus sian mo del. ten yea rs la ter cressie (1991) des cri bed geos ta tis ti cs as one of the three main fi el ds in spa tial sta tis ti cs. isaaks & srivastava (1989) pub lished their we ll ac cep ted ea sy-lear ni ng geos ta tis ti cs book for re ser voir cha rac te ri za tion. deutsch & journel (1997) pro du ced their geos ta tis ti cal lib ra ry for the mo st fa mous geosta tis ti cal prog ram gslib. the re are a lot of ot her excel le nt boo ks and pa pe rs. geos ta tis ti cs re cei ved ve ry stro ng in put from mo de rn reser voir cha rac te ri za tion in the ni ne tee n-eig hties. the se re sul ts im pro ved our knowled ge and vi sua li za tion about the sub surfa ce, es pe cial ly in the in te r-we ll area. we ll and seis mic da ta can be ap plied in geos ta tis ti cal mode ls of any ki nd (map pi ng, stoc has tic or in di ca tor si mu la tions). in ge ne ral, geos ta tis ti cal re sul ts can be di vi ded in to two grou ps – de ter mi nis tic and stoc has tic. the geo lo gi cal mo del can be defi ned as de ter mi nis tic if the sa me in pu ts always gi ve the sa me out put, e.g. for the sa me da ta set, usi ng iden ti cal inter po la tion met ho ds, the in te r-we ll area wi ll be map ped consis ten tly ea ch ti me. the mo del is stoc has tic if the in te r-we ll area, es pe cial ly far away from ha r d-da ta, is des cri bed by si milar but dif fe re nt so lu tio ns ea ch ti me. hypot he ti cal ly, the random mo de ls in ea ch ca se wi ll yie ld dif fe re nt re sul ts, but this is to tal ly use le ss and can be con si de red on ly as a pos si bi li ty in un con di tio nal si mu la tio ns. ac cor di ng to the clas si fi ca tion of jensen et al. (2000) re ser voi rs can be con si de red as: 1. com ple te ly de ter mi nis tic re ser voi rs whe re the in te rwe ll area is we ll known, cor re la ted and des cri bed by pa laeoen vi ron men ts. howe ver, su ch lo ca li ties are ra re, and mos tly in clu de ma tu re fi el ds, wi th a lot of wel ls. the se are of in te re st on ly in the de ve lop me nt sta ge or when sear chi ng for »by-pas se d« oil; 2. stoc has tic re ser voi rs are tho se that in clu de so me un certain ties, but whe re the ar chi tec tu re is mos tly known at the mac ro-sca le. howe ver, the in te r-we ll area can not be des cri bed for cer tain, and im pro ved in ter po la tion met ho ds, li ke geos ta tis ti cs, are ve ry de si rab le. 3. ran dom re ser voi rs are ve ry ra re and are mos tly not a goal of geo lo gi cal mo del li ng. the re are on ly se ve ral wel ls and/or gra vi met ric and mag ne to met ric da ta that cou ld be des cri bed by mon te car lo sam pli ng or by analo gy wi th si mi lar pros pec ts. the geos ta tis ti cal de ter mi nis tic ap proa ch in clu des dif fe rent kri gi ng and cok ri gi ng met ho ds. a stoc has tic ap proa ch al so en com pas ses dif fe re nt met ho ds that can rep re se nt the re servoir throu gh a set of rea li za tio ns. for the mo st pa rt, the stochas tic ap proa ch can be mo re des crip ti ve than de ter mi nis tic met ho ds. howe ver, the re is al so a se co nd ad di tio nal sour ce of in for ma tion, whi ch can im pro ve any re ser voir pic tu re whet her the de ter mi nis tic or stoc has ti cal ap proa ch has been used. these are seis mic at tri bu tes. cok ri gi ng is a de ter mi nis tic ap proach that uses seis mi cs as a secon da ry sour ce of in for ma tion, des cri bi ng the in te r-we ll area in mo re de tail than has been possib le usi ng kri gi ng. stoc has tic si mu la tio ns ba sed on cok ri gi ng as ze ro-rea li za tion, al so use seis mic at tri bu te(s) as se con da ry sour ces of in for ma tion. the con sta nt »prob le m« is the re lia bili ty of seis mic in pu ts, i.e. whet her they cor re la te wi th we ll data or ju st show a tre nd. se ve ral pa pe rs re cen tly pub lis hed in croa tian jour na ls, intro du ced geos ta tis ti cal theo ry to the croa tian geo lo gi cal commu ni ty, and show the dif fe re nt met ho ds ap plied at se ve ral hydrocar bon fi el ds. in his dis ser ta tion, malvić (2003), used da ta from the bje lo var sub dep res sion and ana lyzed it by expe ri mental va riog ra ms. malvić & ðureković (2003) com pa red the re sul ts of po ro si ty map pi ng in li mi ted in put da ta se ts ob tained by three dif fe re nt met ho ds – in ver se dis tan ce weig hti ng, or di na ry kri gi ng and col lo ca ted cok ri gi ng. the sum ma ry resul ts of po ro si ty map pi ng of the enti re wes te rn pa rt of the drava dep res sion (mol ve, ka li no vac and sta ri gra dac) we re publis hed by malvić (2005). fi nal ly, the geos ta tis ti cal ap proa ch had been con nec ted to de po si tio nal mo de ls and po ro si ty dis tribu tion, (malvić, 2006). the fi r st stoc has tic ap proac hes we re ap plied by smoljanović & malvić (2005). the ever pre se nt and le gi ti ma te en gi nee ri ng and scien ti fi c ques tion is, whi ch ap proa ch is mo re ap prop ria te – the de ter minis tic li ke kri gi ng or cok ri gi ng or the stoc has tic that va ries har d-da ta in sta tis ti cal ly al lowed li mi ts. the aim he re is to eit her an swer this ques tion, or pro vi de a mea ns of as ses si ng whi ch wou ld be the be st choi ce. 2. kriging and cokriging theory the theo ry of va riog ram ana lysis has been explai ned in ma ny pa pe rs and boo ks, and rep re sen ts the ne ces sa ry in put for kri gi ng and cok ri gi ng inter po la tion met ho ds. de ter mi na tion of spa tial de pen den ce is mos tly do ne by a va riog ram fun ction cal cu la tion (equa tion 1.0): h n z x z x h2 1 i i i n 1 $c = + = _ ` `i j j9 c! (1.0) whe re are: h2c _ i – va riog ram n – num ber of da ta pai rs com pa red on h dis tan ce z xi ` j– va riab le va lue on cho sen lo ca tion (xi) z x hi +` j – va riab le va lue on the lo ca tion wi th »h« distan ce from the ini tial lo ca tion (xi+h) va riog ram va lue de pen ds on ly on the spa tial dis tri bu tion of lo ca tio ns, e.g. on the num ber of known va lues over a cho sen dis tan ce. the re sul ts are expe ri men tal va riog ram cur ves, descri bed wi th theo re tic mo de ls, whi ch are the in put for geos ta tisti cal es ti ma tion met ho ds. the ba sic geos ta tis ti cal es ti ma tion theo ry is cal led kri gi ng, whi ch can be exten ded to cok ri gi ng and stoc has tic met ho ds. in ge ne ral, kri gi ng tec hniques are called the be st li near un bia sed es ti ma to rs (ab br. blue), exce pt 05 malvic.indd 3805 malvic.indd 38 24.6.2008 11:10:1824.6.2008 11:10:18 geologia croatica 39 tomislav malvić: kri gi ng, cok ri gi ng or stoc has ti cal si mu la tio ns, and the choi ce be tween de ter mi nis tic or sequen tial ap proac hes for sim ple kri gi ng whi ch is on ly the be st un bia sed es ti ma tor. the be st shows that weig hti ng coef fi cien ts are cal cu la ted from mi ni mum kri gi ng va rian ce, li near mea ns that es ti ma tion is done by li near com bi na tion of ha r d-da ta, un bia sed es ti ma tion assu mes that expec ta tion va lue is true for the en ti re ima gi na ry po pu la tion and es ti ma tion is met ho do lo gy. the ge ne ral kri gi ng for mu la is shown in equa tion 1.1: z z xk i i n i 1 #m= = ` j! (1.1) the re gio na li zed va riab le is es ti ma ted at lo ca tion (zk) from exis ti ng ha r d-da ta z xi ` j at lo ca tion xi accom pa nied by a true weig hti ng coef fi cie nt (li ). it al so mea ns that in put da ta are cha rac te ri sed by a gaus sian dis tri bu tion (whi ch is of ten not the ca se, and da ta are tran sfor med in a gaus sia n-li ke or stan da rd nor mal pro ba bi li ty dis tri bu tion). fi nal kri gi ng va lues are al so shown by a nor mal dis tri bu tion. this sim ple for mu la gi ven in eq. 1.1 can be exten ded in kri gi ng mat rix equa tio ns that can be symbo li cal ly shown as equa tion 1.2: w b# m =6 6 6@ @ @ (1.2) this is sim ple mat rix for mu la that des cri bes all kri gi ng tec hniques li ke sim ple kri gi ng, or di na ry kri gi ng, in di ca tor kri gi ng, uni ver sal kri gi ng, dis jun cti ve kri gi ng and ot he rs. the cal cu la tion of the weig hti ng coef fi cie nt is the main ta sk of the kri gi ng equa tio ns. the hig her va lues wi ll be cal cu la ted for the ha r d-da ta lo ca ted at the prin ci pal axis of the ani sot ropy. the se coef fi cien ts al so can be ne ga ti ve, but the con di tion 1m =! is sa tis fi ed for or di na ry kri gi ng that is used in this ana lysis. mo reo ver, va riog ram ana lysis can poin ted at geo lo gi cal ele men ts li ke struc tu ral axes, de po si tio nal chan ne ls etc. the weig hti ng coef fi cie nt va lues fi nal ly de pe nd on ly on dis tan ces amo ng ha r d-da ta in clu ded in an el lip soid of spa tial de pen dence. howe ver, ad van ta ges of geos ta tis ti cs can not be con fi r med in ca ses of ve ry li mi ted in put da ta se ts. su ch a li mit can be set at 10 or 15 ha r d-da ta poin ts, be cau se smal ler da ta se ts can not be des cri bed by a va riog ram mo del. cok ri gi ng, li ke kri gi ng, al so in clu des se ve ral es ti ma tion tec hniques, mos tly iden ti cal kri gi ng tec hniques (sim ple cokri gi ng, or di na ry cok ri gi ng etc.). the on ly con di tion is the intro duc tion of a se con da ry va riab le (or co-va riab le) that is: (a) in mea nin gful con nec tion wi th the pri ma ry va riab le, (b) sampled at ma ny lo ca tio ns and (c) sig ni fi can tly cor re la ted wi th the pri ma ry va riab le. the mat he ma ti cal exten sion is ve ry simple, de ri ved from eq. 1.1 and is gi ven in equa tion 1.3: z z x w yi i n i j j n j 1 1 z w $ $m |= + = = ` aj k! ! (1.3) whe re: z z xi i n i 1 z $m= = ` j! = the pa rt ap plied to the pri ma ry va riab le, w yj j n j 1 w $| = a k! = the pa rt ap plied to the se con da ry variab le. cok ri gi ng met ho ds and co-re gio na li zed va riab les are re la ted in the sa me way as the theo ry of re gio na li zed va riab les and krigi ng. co re gio na li za tion des cri bes the spa tial va ria tion of se veral va riab les. this is exten ded from the theo ry of kri gi ng and a re gio na li sed va riab le to se ve ral cok ri gi ng va riab les. the se va riab les ha ve a mul ti va ria te spa tial cro ss-cor re la tion as we ll as the uni va ria te spa tial au to-cor re la tion. they are then cal led co-re gio na li zed va riab les and can be used to un der sta nd spatial pro ces ses that ma ni fe st them sel ves as se ve ral mea su red va riab les (rossiter, 2005). two or mo re de pen da nt va riables can al so be in ter po la ted from col lo ca ted ob ser va tio ns using reg res sion kri gi ng or kri gi ng wi th exter nal dri ft, but this is not dis cus sed he re. mo re of ten the re are mo re ob ser va tio ns of the co-va riab le, i.e. at so me poin ts whe re the tar get va riable was not mea su red and requi res co re gio na li za tion. a typi cal exam ple is seis mic sig na ls re cei ved from lit ho lo gi cal boun daries and sec tio ns of a hydro car bon re ser voir. co re gio na li za tion is a ge ne ral te rm for the theo re ti cal mo del of how se ve ral va riab les spa tial ly co-va ry. the idea is that the pro ce ss that gi ves ri se to one va riab le is the sa me, or at lea st re la ted, to the pro ce ss that is ma ni fe st in the ot her variab les. all the va riab les in vol ved are re gio na li zed va riab les and in ad di tion they are re la ted bo th in fea tu res and geog raphic spa ce, hen ce they are co-re gio na li zed. the pro ce du re of co re gio na li za tion can be refl ec ted in the va riog ram cal cu lation, whi ch mea ns that the re cou ld be two types of va riog ra ms mo del led: (a) di rec tio nal or om ni di rec tio nal va riog ra ms cal cula ted for a sin gle re gio na li zed va riab le, i.e. one va riog ram per va riab le (see eq. 1.1) or (b) cro ss va riog ra ms cal cu la ted for the pair of re gio na li zed va riab les e.g. as des cri bed in rossiter, (2005). from equa tion 1.3, de ter mi na tion of weig htin gs for λ (the tar get va riab le) and χ (for the co-va riab le), mi ni mi zes the predic tion er ror. it is why cok ri gi ng can be des cri bed, li ke kri gi ng, by the ac ro nym blue (be st li near un bia sed es ti ma tor). this sho rt re view of de ter mi nis tic geos ta tis ti cal too ls is on ly a mi ni mal sum ma ry ne ces sa ry for un der stan di ng the resear ch des cri bed in this pa per. mo re de tai ls can be fou nd in ma ny pub li ca tio ns in clu di ng goovaerts (1997), hohn (1988), isaaks & srivastava (1989), journel & huijbregts (1978), liebhold et al. (1993), xu et al. (1992) and ot he rs. 3. the concept of stohastic simulations si mu la tio ns, wri ti ng li te ral ly, pre ser ve the fl a vour of real sub sur fa ce va ria bi li ty, map pi ng all pos si bi li ties be tween the extre me va lues of the re gio na li zed va riab le. if si mu la tion is »con di tio na l«, it ho nou rs the ob ser ved da ta exac tly, wit hout the at ten da nt smoot hi ng of the in ter po la ted es ti ma tes, as in kri gi ng. si mu la tion pro vi des vi sual and quan ti ta ti ve mea su res of the un cer tain ty of the es ti ma ted va riab le (»co si mu la tio n«, ana lo gous to cok ri gi ng). da ta are ho nou red whe re the un derlyi ng tre nd or pat te rn is rep ro du ced (e.g. as in kri gi ng), whe reas da ta are rep ro du ced whe re pre dic ted va lues are for ced to be equal to ob ser ved va lues. the re is, of cour se, a dif fe ren ce be tween si mu la tio ns and kri gi ng. kri gi ng pro du ces ju st one map of es ti ma tes whi ch is 05 malvic.indd 3905 malvic.indd 39 24.6.2008 11:10:1924.6.2008 11:10:19 geologia croatica geologia croatica 61/1 40 »bes t« (a nd hen ce unique) in so me sta tis ti cal sen se, but whi ch does not rep ro du ce glo bal sta tis ti cs (his tog ram, va rian ce, cova rian ce). kri gi ng is a glo bal es ti ma tor, and its es ti ma te repre sen ts all the da ta wit hin a de fi ned va riog ram el lip soid. the kri ged grid ho nou rs da ta poi nt-va lues on ly if the parti cu lar poi nt coin ci des wi th a grid no de. the kri gi ng map is use ful to show smoo th va ria tio ns and un der lyi ng tren ds, but not the in he re nt lo cal va ria bi li ty of the da ta. kri gi ng pro vi des an in com ple te mea su re of lo cal ac cu ra cy (i.e. kri gi ng »va riance« may not rep re se nt a gaus sian dis tri bu tion of er ro rs), and no mea su re of joi nt ac cu ra cy when se ve ral lo ca tio ns are consi de red to get her. all the se fac ts are al so va lid for cok ri gi ng tec hniques. the si mu la tion is al so a lo cal es ti ma tor. the goal is the rep ro duc tion of glo bal pat ter ns of spa tial con ti nui ty and global sta tis ti cs (his tog ram, co va rian ce), rat her than lo cal ac cu racy. si mu la tion is used to de mon stra te the na tu re of lo cal va riabi li ty and glo bal pat ter ns of lo cal va ria bi li ty, su ch as the con nec tio ns and tren ds amo ng dif fe ren tial ly va lued re gio ns. the si mu la tion pro du ces any num ber of sta tis ti cal ly equi va lent ma ps whi ch, when ta ken to get her, de fi ne the lo cal es ti mation un cer tain ty as we ll as the glo bal pat te rn of un cer tain ty. un der ta ki ng si mu la tion, se ve ral ap proac hes can be se lec ted (welhan, 2001): • si mu la ted va riab les can be con ti nuous or ca te go ri cal; • con di tio nal si mu la tion rep ro du ces the ob ser ved da ta; • un con di tio nal si mu la tion on ly rep ro du ces glo bal sta tis ti cs (his tog ram, va riog ram, etc.); • ca te go ric va riab les can be si mu la ted to honour spe cifi c geo met ric pat ter ns (ob je ct-ba se d); • con ti nuous va riab les can be si mu la ted to ho nour a speci fi ed co va rian ce mo del; • va riab les can be si mu la ted throu gh op ti mi za tion proces ses star ti ng from scrat ch or from pre vious ly-si mu lated ima ges, to ho nour ad di tio nal, exter nal, con strai ni ng da ta. gaus sian si mu la tion, usi ng con ve nien ce (bo th theo re tical and prac ti cal) wi th whi ch gaus sian dis tri bu tio ns can be des cri bed and han dled sta tis ti cal ly ma kes a gaus sian ran dom fun ction mo del ve ry ap pea li ng. this cla ss of si mu la tion al gorit hms is res tric ted to con ti nuous va riab les. gaus sian si mu lation can be ap plied if the pro ba bi li ty dis tri bu tion fun ctio ns (pdf’s) of all va riab les that par ti ci pa te in the si mu la tion, (e.g. a re gio na li zed va riab le plus its lo cal un cer tain ty or va rian ce) are nor mal ly dis tri bu ted. the mo st im por ta nt con di tion is that the va riab les are uni va ria te and bi va ria te nor mal and in de pende nt. the as sum ption of nor ma li ty is not res tric ti ve for rea lwor ld da ta, sin ce a nor ma l-sco re tran sfo rm can be ap plied to ma ke any da ta set nor mal ly-dis tri bu ted. the mo st se rious li mita tion for real da ta is that a re gio na li zed va riab le at a gi ven loca tion is of ten not in de pen de nt. it may be cor re la ted wi th its lo cal va rian ce, (via a pro por tio nal ef fe ct) and/or it may ha ve stro ng lo cal spa tial cor re la tion, (e.g. in ter con nec ted hi gh or low va lues). welhan (2001) in di ca ted stro ng lo cal spa tial cor re la tion as the ma jor pos sib le prob lem, and re com men ded a met hod des cri bed in deutsch & journel (1997) for chec ki ng and ne ces sa ry ap pli ca tion if the gaus sian si mu la tion ap proa ch is to be cor rec tly de fen ded. the pro por tio nal ef fe ct can be neg lec ted if it is weak or is re mo ved by mo vi ng the variog ram el lip soid (sear ch neig hbor hood). des pi te su ch ca veats, the gaus sian si mu la tion ap proa ch is wi de ly used; its in tuiti ve and al go rit hmic sim pli ci ty de fi ne its wi des pread ap peal. sequen tial si mu la tion al go rit hm (e.g. deustsch & journel, 1997) con tai ns a po pu lar cla ss of al go rit hms that is in wi des pread use. su ch an approa ch is ve ry of ten in the gaus sian ver sion as sequen tial gaus sian si mu la tion, but can al so be ap plied in si mu la tio ns of ot her types. the sequen tial si mu la tion ap proa ch can be bro ken down con cep tual ly in to three par ts (welhan, 2001): • the ini tia li za tion pro ce ss; • a glo bal ran dom wa lk pro ce ss and • a lo cal sear ch and con di tio nal ran dom es ti ma tion proce ss. ini tia li za tion de ter mi nes the uni va ria te cu mu la ti ve dis tribu tion fun ction (cdf) from the en ti re stu dy area, usi ng declus te ri ng if ne ces sa ry. a nor ma l-sco re tran sfo rm of the da ta usi ng a stan da r d-nor mal cdf mu st be per for med, and a re gular grid ne two rk of no des de fi ned, at whi ch es ti ma tes wi ll be ma de. da ta poin ts may be re-lo ca ted to the se grid no des (for fas ter com pu ta tion) or not (for maxi mum ac cu ra cy). typi cally, this grid ne two rk wi ll be mu ch fi ner than was used in kri ging, be cau se si mu la tion at tem pts to rep ro du ce the na tu re of local va ria bi li ty and un cer tain ty. the glo bal ran dom wa lk pro ce ss uses a ran dom number seed. the es ti ma tion star ts at a ran dom lo ca tion on a grid ne two rk wi th the ran dom num ber ge ne ra tor, mo ves to subseque nt ran dom lo ca tio ns af ter a local sear ch has been comple ted, but ne ver vi si ts the sa me grid no de twi ce. the es ti mated da ta are con si de red as the new ha r d-da ta va lues. lo cal sear ch and con di tio nal es ti ma tion pro ce ss loo ks wit hin a de sig na ted sear ch neig hbor hood for a pres cri bed number of nea re st neig hbo rs, com pri si ng bo th ori gi nal da ta and/or pre vious ly si mu la ted va lues (welhan, 2001). it uses the variog ram mo del of nor ma l-sco re da ta wi th sim ple kri gi ng to es ti ma te the mean and va rian ce at the grid no de lo ca tion. this de fi nes the cu mu la ti ve dis tri bu tion fun ction (cdf) of the regio na li zed va riab le at that sear ch neig hbor hood lo ca tion. in the ca se of neit her ha r d-da ta or pre vious ly si mu la ted no des exis ti ng wit hin the sear ch neig hbour hood, the cdf is con ditio nal on ly to the glo bal his tog ram. the va lue es ti ma ted at such a grid no de wi ll be a va lue drawn at ran dom from the cdf es ti ma ted from the glo bal his tog ram (welhan, 2001). at the end of this pro ce ss, the si mu la ted nor ma l-sco re va lues are tran sfor med ba ck in to si mu la ted va lues for the ori gi nal va riable. the des cri bed al go rit hm is re pea ted for mul tip le rea li za tions, star ti ng ea ch ti me at a dif fe re nt ini tial grid lo ca tion and visi ti ng grid no des in a dif fe re nt or der. the gaus sian si mu la tion ten ds to ove res ti ma te lo cal spa tial en tro py, crea ti ng mo re ap pa re nt va ria bi li ty than is actual ly pre se nt, this bei ng the mo st ob vious li mi ta tion of si mula tion. it is al so not suf fi cien tly fl exib le to han dle a mixtu re of 05 malvic.indd 4005 malvic.indd 40 24.6.2008 11:10:1924.6.2008 11:10:19 geologia croatica 41 tomislav malvić: kri gi ng, cok ri gi ng or stoc has ti cal si mu la tio ns, and the choi ce be tween de ter mi nis tic or sequen tial ap proac hes dif fe re nt nor mal po pu la tio ns. fur ther mo re, sequen tial si mu lation does not al low the in cor po ra tion of ca te go ri cal da ta (e.g. 1 and 0), but this is over co me by in tro du ci ng an indi ca tor simu la tion al go rit hm. the gaus sian sequen tial si mu la tion approa ch is wi de ly used des pi te the se li mi ta tio ns. anyo ne in te res ted in geos ta tis ti cal theo ry, bo th de ter minis tic or stoc has tic, as ap plied in the croa tian pa rt of the panno nian ba sin is ad vi sed to fol low the re sear ch pre sen ted in malvić (2003, 2005, 2006) or smoljanović & malvić (2005). 4. example 1: cokriging or stochastic co-simulation the beni čan ci fi e ld is the lar ge st hydro car bon re ser voir in the be ni čan ci oil zo ne, and the lar ge st oil pro du ci ng fi e ld in the croa tian pa rt of the dra va dep res sion (fi gu re 1). the oil re ser voir is lo ca ted in brec cia of ba de nian age, and is over lain by struc tu ral ly shal lower and smal ler gas re ser voi rs. this fi e ld and the enti re zo ne lo ca ted in the eas te rn pa rt of the dra va dep res sion, has been stu died for de ca des. the dif fe re nt geo logi cal and pet ro leum set tin gs ha ve been pub lis hed in ma ny pa pe rs. šimon & batušić (1974) des cri bed the lit hos tratig rap hic sec tion of the be ni čan ci fi e ld. turajlić et al. (1979) com pa red the de ve lop me nt of the be ni čan ci, obod and la dis lav ci-ku čan ci fi el ds. hernitz et al. (1993, 1995) des cri bed shal low on sho re clas ti cs of mio ce ne age and sour ce roc ks in the wi der area of the be ni čan ci fi e ld, as we ll as in ot her par ts of the dra va dep res sion. the de po si tio nal mo del of neo ge ne clas ti cs was in de tai l described by tišljar (1993). struc tu ral ly, the fi e ld is de fi ned by brac hian tic li ne axes of 8.0 by 1.3 km, faul ted mos tly by dis pla ce men ts cha rac te ri sed by a nw-se stri ke. howe ver, the main re ver se fau lt clo ses the struc tu re in the sou th (fi gure 2). the en ti re fi e ld is an antic li no rium that in clu des four smal ler an tic li nes, sin ki ng towa rd the ea st. the stra tig rap hy in clu des ba se men ts roc ks of per mian and trias sic age and neo ge ne clas tic se di men ts. dif fe re nt ba se ment schis ts are de ter mi ned on ly in wel ls dee per than 2500 metres. the mio ce ne stra tig rap hy is ve ry he te ro ge neous. the ol dest roc ks are spo ra di cal ly rep re sen ted by ef fu si ves be lon gi ng to the mio ce ne mag ma tic cycle, whi ch ha ve been par tial ly re-depo si ted. their la te ral equi va len ts are trias sic li my brec cia and quar tzi tes that ha ve al so been re de po si ted. the main se di menta ry sequen ce is of ba de nian age, rep re sen ted by do lo mi tic and li mes to ne brec cia. det ri tus is mos tly do lo mi tic and can rea ch met re di men sio ns. the mat rix is al so of mic ro to crypto do lomi te, tec to ni cal ly crus hed, pet ri fi ed and crystal li zed. re ser voir car bo na te brec cias are cha rac te ri sed by re la ti ve ly low pri ma ry po ro si ty, but se con da ry pro ces ses (in clu di ng dis so lu tion, faulti ng and frac tu ri ng) re sul ted in in crea sed se con da ry po ro si ty. the shal low pa rt of the re ser voir is cha rac te ri sed by a mixtu re of brec cia and con glo me ra te, wi th mixed car bo na te and si li ciclas tic det ri tus. in ge ne ral, ba de nian brec cias we re de po si ted in a shal low ma ri ne en vi ron me nt, and con sequen tly cou ld be rede po si ted and weat he red by cur ren ts and wa ve fron ts. tišljar (1993) des cri bed this ba de nian se di men ta ry sequen ce throu gh four types of pos sib le re ser voi rs as fol lows: fi gu re 1: lo ca tion map of the be ni čan ci and sta ri gra da c-bar cs nyu gat fi el ds in dra va dep res sion 05 malvic.indd 4105 malvic.indd 41 24.6.2008 11:10:1924.6.2008 11:10:19 geologia croatica geologia croatica 61/1 42 1. cli no fo rm bo dies of car bo na te roc kfa ll and deb ri te breccias; 2. near sho re con glo me ra tes; 3. chan nel and fan bo dies ma de of brec cia-con glo me rates and san dsto nes. 4. tec to nic brec cias, ge ne ra ted by crus hi ng and tec to ni zation of pre vious ly lit hi fi ed mio ce ne tur bi di te se di me tary roc ks. the ob ser ved re ser voir mos tly be lon gs to type 4 and partial ly to type 1. ba de nian se di men ts we re over lain by a typi cal, youn ger se di men ta ry sequen ce in the dra va dep res sion. this be gan wi th lower pan no nian cal ci tic mar ls (»croa ti ca bed s«), whi ch we re ero ded, on the sout he rn pa rt of the fi e ld. then, la te panno nian se di men ts (»ba na ti ca bed s«) of si mi lar lit ho lo gy we re de po si ted, whi ch are in te res tin gly cha rac te ri sed by grea ter thicknes ses in the sout he rn pa rt of the struc tu re. ear ly pon tian sedi men ts (»a bic hi bed s«) are mos tly san dsto nes (mixtu re detri tus) in ter ca la ted wi th ha rd mar ls. la te pon tian (»r hom boi dea bed s«) se di men ts are mos tly weak san dsto nes and me dium to weak mar ls, so me ti mes clayey, in clu di ng coal. the youn ge st se di men ts of plio ce ne age are mos tly un con so li da ted clay and sa nd, as we ll as qua ter na ry gra vel, sa nd and clay wi th li mesto ne con cre tio ns. the tar get, or pri ma ry, va riab le that had been geos ta tis tical ly ana lyzed in the brec cia re ser voir of ba de nian age was the ave ra ge re ser voir po ro si ty. four teeen lo ca tio ns (or wel ls) we re cho sen as the mo st rep re sen ta ti ve ha r d-da ta poin ts, de rived from the newe st lo g-cur ve ana lyses. the se va lues are mostly re gu lar ly dis tri bu ted ac ro ss the re ser voir area, and can be ob ser ved on the po ro si ty ma ps. mo reo ver, the ana lysed re ser voir is al so co ve red by 3d seis mic cu be and in ter pre ted at tri bu tes. at tri bu te ana lysis was tar ge ted for the inter val that rep re sen ts the re ser voir de fi ned by per meab le lit ho lo gy. it be gi ns 20 m from the seal ro ck in the youn ge st ba de nian se di men ts and con ti nues to eit her the re ser voir ba se de fi ned by pa laeo zoic ba se me nt roc ks, or the ba se of the we ll whe re the ba se me nt roc ks we re not dril led. seis mic at tri bu te ana lysis en com pas ses am pli tu de at tri bu tes, frequen cy and pha se. the exis ten ce of seis mic at tri bu tes ma de ap pli ca tion of geos ta tis ti cal in ter po la tion of the cok ri gi ng pos sib le. the cok ri gi ng requi res the de ter mi na tion of an ad di tio nal, se con da ry va riab le that des cri bes the be ha viour of the pri ma ry one. six at tri bu tes we re cor re la ted wi th po ro si ty, sear chi ng for a connec tion. un for tu na te ly, the va lues of the pear son cor re la tion coef fi cie nt did not show any sig ni fi ca nt cor re la tion, due to the absen ce of a gaus sian dis tri bu tion in the ana lyzed va riab les. it was mo re ap prop ria te to use the no n-pa ra met ric spear man ra nk cor re la tion coef fi cie nt, ba sed on a median va lue (in stead of nor mal dis tri bu tion pa ra me te rs li ke stan da rd de via tion and mean). the hig he st cor re la tion was cal cu la ted for the pair poro si ty-refl ec tion stren gth (as a de ri va ti ve of am pli tu de) whe re the va lue of r’ = – 0.64. the re le va nt va riog ram mo del had been de fi ned alo ng fi eld struc tu ral axes. the di rec tion of the pri ma ry va riog ram axis was 90-270o (e-w), whi le the se con da ry sprea ds oc cur red alo ng the di rec tion 0-180o. due to the low num ber of da ta, the an gle to le ran ce was set at a maxi mum va lue of 45o. the ranges are al mo st isot ro pic – for the main axis the ran ge is 1750 met res de ter mi ned from 7 or mo re da ta pai rs. the ran ge of the se con da ry axis is 1500 met res, de ter mi ned sub jec ti ve ly con side ri ng on ly 5 or le ss da ta pai rs, and con sequen tly on ly 4 existi ng poin ts. expe ri men tal va riog ra ms had been ap proxi ma ted by sphe ri cal theo re ti cal mo de ls. the cok ri gi ng re sul ts are pre sen ted in fi gu re 3b. the selec ted tec hnique was col lo ca ted cok ri gi ng. the wo rd »col lo cate d« mea ns that the pri ma ry and se con da ry va riab les we re obser ved at the sa me lo ca tio ns, i.e. the se con da ry va riab le had been extra po la ted at the sa me lo ca tio ns whe re the ha r d-da ta exist. the cok ri gi ng re sul ts we re sig ni fi can tly bet ter and mo re descrip ti ve in the in te r-we ll areas than the kri gi ng re sul ts (malvić & ðureković, 2003). this cou ld ea si ly be con clu ded from re sul ts of the cro ss-va li da tion met hod (davis, 1987), whe re the cok ri gi ng map was cha rac te ri sed by a mean squa re er ror of 2.19 and the kri gi ng map by the va lue of 2.97. fi gu re 2: palaeo re lief map of the be ni čan ci fi e ld (after futivić & pleić, 2002) 05 malvic.indd 4205 malvic.indd 42 24.6.2008 11:10:2024.6.2008 11:10:20 geologia croatica 43 tomislav malvić: kri gi ng, cok ri gi ng or stoc has ti cal si mu la tio ns, and the choi ce be tween de ter mi nis tic or sequen tial ap proac hes al thou gh the to tal dif fe ren ce be tween the kri gi ng and cokri gi ng ma ps (fi gu re 3a and 3b), in a nu me ri cal sen se, is about 25%, this dif fe ren ce is mos tly re gu lar ly dis tri bu ted ac ro ss the en ti re re ser voir area. the se con da ry ap proa ch for po ro si ty dis tri bu tion at the sa me re ser voir in clu ded usi ng sequen tial gaus sian si mu latio ns (e.g. dubrule, 1998 and kelkar & perez, 2002), as an ap proa ch that cou ld in clu de the ma jo ri ty of un cer tain ties con nec ted to the in put da ta and in te r-we ll area, es pe cial ly in zo nes dis ta nt from ha r d-da ta. a set of on ly four stoc has ti cal equal ly pro bab le rea li za tio ns we re cal cu la ted, whi ch we re found to expre ss the noi sy na tu re of the ha r d-da ta. ge ne ral ly, there mu st be at lea st 100-200 rea li za tio ns for ac cep tab le mea sure me nt of the deg ree of un cer tain ty. the se rea li za tio ns we re ba sed on a cok ri gi ng map as »ze ro« rea li za tion. due to stoc has tic theo ry, da ta we re nor ma li zed to gaussian dis tri bu tio ns and their pdf cur ve was used to sam ple new po ro si ty va lues. the new, da ta set ke pt the sa me sta tis ti cs charac te ris tic as the in put da ta set. ea ch ce ll has a po ro si ty va lue sam pled from its own nor mal ly sha ped pdf de fi ned wi th mean and va rian ce va lues cha rac te ris tic for the cok ri gi ng »zero« rea li za tion (e.g. deutsch, 2002). the or der of the si mula ted cel ls was ran dom and sequen tial. the »extre me« rea li za tion p1 and p99 are shown on figu re 4. the symbol p1 mea ns that 99 % of all ot her pos sib le rea li za tio ns wou ld des cri be lar ger to tal re ser voir po ro si ty. the mea ni ng of p99 rea li za tion is the op po si te. the com pa ri son by cok ri gi ng map, or ze ro »so lu tio n«, re vea ls that the p99 reali za tion loo ks ve ry si mi lar to the cok ri gi ng map. fur ther mo re, it can be con clu ded that the cok ri gi ng map is a ve ry good repre sen ta tion of po ro si ty dis tri bu tion, and the stoc has tic so lu tion sug ges ts that map ped un cer tain ties in the in te r-we ll area can be con si de red pret ty ho mo ge neous for the en ti re sta tis ti cal range. due to the fa ct that gaus sian si mu la tion ove res ti ma tes local va ria bi li ty, to get her wi th the ob ser ved si mi la ri ty be tween the de ter mi nis tic and stoc has tic rea li za tio ns in the ca se of the exis ti ng seis mic at tri bu te and li mi ted da ta set (about 15 ha r d-data), the cok ri gi ng ap proa ch is to be re com men ded rat her than the use of gaus sian si mu la tio ns. 5. example 2: kriging or stochastic simulation the sta ri gra da c-bar cs nyu gat ga s-con den sa te fi e ld is lo cated on the croa tia n-hun ga rian bor der, alo ng the dra va ri ver, ap proxi ma te ly 150 km ea st of zag reb. the fi e ld is si tua ted in fi gu re 3: kri gi ng (fi gu re 3a – abo ve) and cok ri gi ng (fi gu re 3b – be low) ma ps of po ro si ty dis tri bu tion 05 malvic.indd 4305 malvic.indd 43 24.6.2008 11:10:2124.6.2008 11:10:21 geologia croatica geologia croatica 61/1 44 the nor thwes te rn pa rt of the dra va dep res sion (fi gu re 1). a mas si ve (an tic li ne) re ser voir is trap ped by a com bi ned struc tura l-stra tig rap hic clo su re (fi gu re 5). the lit ho lo gy of the re servoir is ve ry com plex, di vi ded in to four lit ho fa cies: ‘clas ti tes’ of ba de nian age, ‘do lo mi tes’ of lower trias sic age, ‘quar tzites’ of lower trias sic age and ‘me ta vol ca ni tes’ of per mian, de vo nian and (pos sib ly) car bo ni fe rous age. the re sul ts of geos ta tis ti cal po ro si ty map pi ng in lit ho facies ‘clas ti tes’ of ba de nian age that in clu ded mos tly car bo nate brec cia are ana lysed he re. the se re ser voir lit ho fa cies are lit ho lo gi cal ly com pa rab le to coar se-grai ned bade nian lit ho facies ana lysed from the be ni čan ci fi e ld. the in put da ta set was re la ti ve ly sma ll in num ber, whi ch con sequen tly exclu ded the exis ti ng arit hme tic mean as bei ng va lid for a glo bal mean (i.e. exclu ded con di tion of fi r st-or der sta tio na ri ty ne ces sa ry for sim ple kri gi ng). or di na ry kri gi ng was se lec ted as the mo st ap prop ria te in ter po la tion tec hnique. the re was no es tab lis hed cor re la tion be tween seis mic at tri butes and po ro si ty. the va riog ram ana lysis was do ne again alo ng the main struc tu ral axes of the fi e ld (fi gu re 5). the prin ci pal va riog ram axis has a stri ke of 120-300o and the su bor di na te stri ke is 30210o. the expe ri men tal va riog ra ms we re cal cu la ted for ea ch lit ho fa cies, and par ti cu lar ly for the ‘clas ti tes’. the ran ges are 3500 met res (prin ci pal) and 2000 met res (su bor di na te axis). the prin ci pal axis mo del li ng is fair ly re liab le ba sed on 8 or mo re da ta pai rs. the mo del li ng of the se con da ry axis is hig hly sub jec ti ve. all va riog ra ms are again ap proxi ma te by sphe ri cal theo re ti cal mo de ls. the kri gi ng map shows a sig ni fi ca nt in ter po la tion im prove me nt com pa red to tho se pre vious ly pro du ced by in ver se distan ce weig hti ng (fi gu re 6). if the se two so lu tio ns are com pa red nu me ri cal ly throu gh cro ss-va li da tion re sul ts, the im pro ve me nt is mo re than 30% – for kri gi ng map 3.91 and for in ver se dis tance weig hti ng map 5.28. it is not dif fi cu lt to explain why the kri gi ng map is mo re ac cu ra te and ac cep tab le for the geo lo gi cal mo del. it is clear that the in ver se dis tan ce weig hti ng map (fi gu re 6, le ft) is unrea lis ti cal ly too de tai led. ba sed on on ly 14 ha r d-da ta poin ts, the smoot hed kri gi ng map (fi gu re 6, rig ht) is mo re rea lis tic and in ter pre tab le. howe ver, the chal len ge is to try to des cri be in te rwe ll area un cer tain ties by stoc has tic si mu la tion as we ll. usi ng res pec ted ha r d-da ta poin ts, i.e. con di tio nal si mu la tio ns, 100 simu la tio ns we re cal cu la ted des cri bi ng re ser voir ran dom ne ss (figu re 7). the re ser voir spa ce is always cha rac te ri sed by un cer tainties. the per ma ne nt prob lem is how to expre ss the se »hid de n« cha rac te ris ti cs in the map ped va riab le. this is es pe cial ly empha si sed in the ca se of a ve ry li mi ted in put da ta set. in this case, for the ‘clas ti tes’ lit ho fa cies at the sta ri gra da c-bar cs nyufi gu re 4: p1 (fi gu re 4a – abo ve) and p99 (fi gu re 4b – be low) equip ro bab le stoc has tic rea li za tio ns 05 malvic.indd 4405 malvic.indd 44 24.6.2008 11:10:2224.6.2008 11:10:22 geologia croatica 45 tomislav malvić: kri gi ng, cok ri gi ng or stoc has ti cal si mu la tio ns, and the choi ce be tween de ter mi nis tic or sequen tial ap proac hes gat fi e ld, the stan da rd de via tion of in put po ro si ty da ta set was hig her than 0.5 of the pos sib le maxi mum. the sta tis ti cal un certain ty is mos tly in clu ded in the variog ram mo del, for ci ng the lar ge pri ma ry ran ge and es ti ma ted ran ge of the su bor di na te axis from the ra tio of the struc tu ral axes. the se fac ts ju st in dica te a stoc has tic ap proa ch as the mo st fa vou rab le for in te r-well area des crip tion. the dif fe ren ces in the set of si mu la ted reali za tio ns (dif fe ren ce be tween p1 and p99) we re about 14% (or mi ni mum vo lu me of ‘clas ti tes’ was 5,241,097 and maxi mum 5,973,280 m3). mo reo ver, it is im por ta nt to em pha sis that both kri gi ng and stoc has tic rea li za tio ns led to a dec rea se in re servoir vo lu me, over that pre vious ly cal cu la ted by in ver se dis tance weig hti ng. in any ca se, whe re the in put da ta set is ve ry li mi ted, wi th the absen ce of an ad di tio nal, sig ni fi can tly cor rela ted seis mic va riab le, the stoc has tic ap proa ch is pre fer red. the sta ri gra da c-bar cs nyu gat da ta set is ve ry li mi ted and it is ha rd to des cri be lo cal va ria bi li ty. a stoc has tic ap proach is mo re des crip ti ve and al lows geo lo gi st to spe cu la te about fea tu res that in fl uen ce po ro si ty dis tri bu tion. fi nal ly it led to bet ter cha rac te ri sa tion of po ro si ty in the in te r-we ll area. 6. conclusions po ro si ty in ter po la tion re sul ts we re com pa red at two si mi lar re ser voi rs from the be ni čan ci and sta ri gra da c-bar cs nyu gat fi el ds. bo th are lo ca ted in the dra va dep res sion, and oc cur in coar se-grai ned se di men ts (car bo na te brec cia) of ba de nian age. the re sear ch goal was to es tab li sh qua li ta ti ve cri te ria to aid the fi gu re 5: struc tu re map of the top of the ‘clas ti te s’ lit ho fa cies (after gaćeša at al., 20013) fi gu re 6: sche ma tic po ro si ty ma ps in ter po la ted by in ver se dis tan ce weig hti ng (le ft) and kri gi ng (rig ht) 2 gaćeša, s., futivić, i, ferencz, g. & horvath, z. (2001): barcs nyugat-stari gradac fi eld; geological evaluation-summary study. unpublished report, company internal fi les, ina naftaplin, sektor za razradu, 27 p. 05 malvic.indd 4505 malvic.indd 45 24.6.2008 11:10:2324.6.2008 11:10:23 geologia croatica geologia croatica 61/1 46 se lec tion of eit her de ter mi nis tic or stoc has tic geos ta tis ti cal ap proac hes for po ro si ty in ter po la tion in ana lyzed re ser voi rs. the fi r st ca se in clu ded use of an ad di tio nal seis mic va riable and con sequen tly the cok ri gi ng met hod. the se co nd example was orien ted on ly on a pri ma ry va riab le in ter po la ted by kri gi ng and com pa ri son of stoc has ti cal rea li za tio ns usi ng the kri gi ng map. in the fi r st ca se, i.e. po ro si ty ana lysis at the be ni čan ci fi e ld, seis mic da ta led to a lower es ti ma tion er ror (cok ri gi ng va rian ce er ror) and for tu na te ly this ad van ta ge was re gu lar ly dis tri bu ted ac ro ss the en ti re re ser voir. mo reo ver, the seis mic at tri bu te at te nua ted the ‘bu ll-eye-ef fe ct’, so ob vious ly pre se nt on the kri gi ng map. the cok ri gi ng map can be con si de red as a ve ry re liab le rep re sen ta tion of the dis tri bu tion of po ro si ty in the brec cia re ser voir in the be ni čan ci fi e ld. the set of stoc hastic rea li za tion re sul ts on ly con fi r med that the cok ri gi ng map can be used as a ‘de fi ni te’ po ro si ty so lu tion, ve ry op ti mis ti cally des cri bi ng the re ser voir, (the cok ri gi ng map is ve ry si mi lar to the stoc has tic map ob tai ned by p99 rea li za tion). mo reo ver, the cok ri gi ng rea li za tion wi ll not te nd to ove r-em pha sis lo cal va ria bi li ty, whi ch cou ld be cha rac te ris tic of co-si mu la tion. the se co nd ca se, ana lysis at the sta ri gra da c-bar cs nyu gat fi e ld, was dif fe re nt be cau se it was not pos sib le to sele ct a se con da ry seis mic sour ce of in for ma tion. ma ny of the un cer tain ties we re again in cor po ra ted in a va riog ram mo del, in a si mi lar way to the be ni čan ci re ser voir. howe ver, the stari gra da c-bar cs nyu gat da ta set was cha rac te ri sed by a very hi gh stan da rd de via tion, al thou gh the re we re on ly 14 ha r d-data poin ts. it mea ns that the mean and va rian ce can not be consi de red as rep re sen ta ti ve, and ran dom ne ss is one of the mo st ob vious re ser voir cha rac te ris ti cs. it stron gly in di ca tes a stochas tic ap proa ch for tes ti ng and cal cu la tion of a re la ti ve ly wi de set of rea li za tio ns (100 ma ps we re cal cu la ted). bo th ap proaches, the kri gi ng and sequen tial gaus sian si mu la tio ns, yiel ded bet ter so lu tio ns than tho se ob tai ned by the inver se dis tan ce weig hti ng met hod. mo reo ver, the stoc has tic ap proa ch led to bet ter re ser voir cha rac te ri za tion, be cau se it de pic ted mu ch more va ria tion in the zo nes dis ta nt from ha r d-da ta than was vi sible on the kri gi ng map. com pa ri ng p1, p50 and p99 rea li za tions on ly the bor der of zo ne of low po ro si ty (red zo ne shown at fi gu re 7) and con sequen tly of hi gh po ro si ty (lig ht blue area fi gu re 7: po ro si ty es ti ma ted in me dian stoc has tic rea li za tion (p50) at fi gu re 7) can be pre dic ted. this zo ne al so in di ca tes the boun da ry be tween bet ter and poo rer par ts of the re ser voir, i.e. at the boun da ry be tween proxi mal and dis tal par ts of the al luvial fan, whe re coar se-grai ned clas ti cs of ba de nian age were de po si ted (malvić, 2006). fi nal ly, bo th exam ples rep re se nt ve ry li mi ted da ta se ts of 14 ha r d-da ta va lues. the re sul ts in di ca ted that if a se con da ry sour ce of in for ma tion (li ke seis mic) is avai lab le then the de termi nis tic cok ri gi ng ap proa ch is re com men ded. howe ver, if the se con da ry va riab le is not avai lab le the stoc has tic gaus sian simu la tion is a mo re des crip ti ve tool. acknowledgement this wo rk is pa rt of mul ti dis cip li na ry geos ta tis ti cal re sear ch that was per for med in 2006 and 2007 wit hin the pro je ct en tit led »stra tig raphi cal and geo mat he ma ti cal re sear ches of pet ro leum geo lo gi cal syste ms in croa tia« (pro je ct no. 195-1951293-0237), fi nan ced by the mi nis try of scien ce, edu ca tion and spor ts of the re pub lic of croatia. the aut hor wou ld al so li ke to tha nk to ma rio weis ser, msc, the di rec tor of re ser voir en gi nee ri ng and fie ld de ve lop me nt de partme nt (as a pa rt of ina-oil in dus try plc.) for per mis sion to pub li sh fi gu re 5. 7. references cressie, n. (1991): sta tis ti cs for spa tial da ta. – wi ley & so ns ltd, 928 p. davis, b. (1987): uses and abu ses of cro ss va li da tion in geos ta tis tics.– mat he ma ti cal geo lo gy, 19/3, 241–248. deutsch, c.v. (2002): geos ta tis ti cal re ser voir mo de li ng.– oxfo rd uni ver si ty pre ss, 376 p. deut sch, c.v. & jour nel, a.g. (1997): gslib: geos ta tis ti cal softwa re lib ra ry and use r’s gui de (ap plied geos ta tis ti cs se ries), seco nd edi tion.– oxfo rd uni ver si ty pre ss, 369 p. dubrule, o. (1998): geos ta tis ti cs in pet ro leum geo lo gy.– aapg edu ca tion cour se no te, se ries #38, aapg and geo lo gi cal so cie ty pub lis hi ng hou se, 210 p. futivić, i. & pleić, m. (2002): 3d seismic interpretation of the be ničanci oil field. naftaplin,1 (19), 17-25. goovaerts, p. (1997): geos ta tis ti cs for na tu ral re sour ce eva lua tion (ap plied geos ta tis ti cs se ries). oxfo rd uni ver si ty pre ss inc., 483 p. hernitz, z., tišljar, j., kalac, k., velić, j. & jelić, k. (1993): mio cen ski si par ni i prio bal ni klas ti ti, te ma tič ne sti je ne u drav skoj dep re si ji [mio ce ne roc kfa ll and coas tal clas ti cs, and source roc ks in the dra va dep res sion – in croatian]. – sav je to va nje o ko lek tor skim sti je na ma u pa non skom ba ze nu, 20.–24.4.1993., zagreb, croa tia. znan stve ni sav jet za naf tu hazu, ab stra ct, 1–2. hernitz, z., velić, j., kalac, k. & saftić, b. (1995): mio censke ta lo ži ne u ši rem pod ruč ju be ni ča na ca i nji ho vo naf tno geo loško zna če nje [mio cene se di men ts in the wi der area of the be ni čanci and their sig ni fi can ce for pet ro leum geo lo gy – in croatian]. 1. hr vat ski geo loš ki kon gres, opa ti ja 18.–21.10.1995., zbor nik ra dova 1, 195–200, zag reb. hohn, m.e. (1988): geos ta tis ti cs and pet ro leum geo lo gy.– van nostra nd rein ho ld, 264 p. isaaks, e. & srivastava, r. (1989): an in tro duc tion to ap plied geos ta tis ti cs. – oxfo rd uni ver si ty pre ss inc., 580 p. jensen, j.l., lake, l.w., corbett, p.w.m. & goggin, d.j. 05 malvic.indd 4605 malvic.indd 46 24.6.2008 11:10:3124.6.2008 11:10:31 geologia croatica 47 tomislav malvić: kri gi ng, cok ri gi ng or stoc has ti cal si mu la tio ns, and the choi ce be tween de ter mi nis tic or sequen tial ap proac hes (2000): sta tis ti cs for pet ro leum en gi nee rs and geos cien tis ts.– prenti ce ha ll ptr, 390 p. journel, a.g. & huijbregts, c.j. (1978): mi ni ng geos ta tis ti cs.– aca de mic pre ss, p. 600. kelkar, m. & perez, g. (2002): ap plied geos ta tis ti cs for re ser voir cha rac te ri za tion.– so cie ty of pet ro leum en gi nee rs, 264 p. krige, d.g. (1951): a sta tis ti cal ap proa ch to so me ba sic mi ne va luation prob le ms on the wi twa ter sra nd.– jour nal of the che mi cal, metal lur gi cal and mi ni ng so cie ty of sou th af ri ca, 52, 119–139. liebhold, a.m., rossi, r.e. & kemp, w.p. (1993): geos ta tis ti cs and geog rap hic in for ma tion system in ap plied in se ct eco lo gy. – an nual re view of en to mo lo gy, 38, 303–327. malvić, t. (2003): vje ro jat no st pro na las ka no vih za li ha ug lji ko vo di ka u bje lo var skoj ulek ni ni [oi l-geo lo gi cal re la tio ns and pro ba bi li ty of dis co ve ri ng new hydro car bon re ser ves in the bje lo var sag – in croatian]. – un pub lis hed phd the sis, fa cul ty of mi ni ng, pet roleum and geo lo gy, uni ver si ty of zag reb, 123 p. malvić, t. (2005): re sul ts of geos ta tis ti cal po ro si ty map pi ng in weste rn dra va dep res sion fi el ds (mol ve, ka li no vac, sta ri gra dac).– naf ta, 56/12, 465–476. malvić, t. (2006): mid dle mio ce ne de po si tio nal mo del in the drava dep res sion des cri bed by geos ta tis ti cal po ro si ty and thic kne ss maps (ca se stu dy sta ri gra da c-bar cs nyu gat fie ld).– ru dar sko-geološ ko-naf tni zbor nik, 18, 63–70. malvić, t. & ðureković, m. (2003): ap pli ca tion of met ho ds: inver se dis tan ce weig hti ng, or di nary kri gi ng and col lo ca ted cok ri gi ng in po ro si ty eva lua tion, and com pa ri son of re sul ts on the be ni can ci and sta ri gra dac fi el ds in croa tia.– naf ta, 54/9, 331–340. mathéron, g. (1962): trai té de géos ta tis tique ap pliquée.– to me 1, edi tio ns tec hnip, 334 p. mathéron, g. (1963): prin cip les of geos ta tis ti cs.– econ. geol., 58/8, 1246–1266. mathéron, g. (1965): les va riab les régio na li sées et leur es ti mation.– mas son & cie, 306 p. ripley, b.d. (1981): spa tial sta tis ti cs.– jo hn wi ley & so ns inc., 252 p. rossiter, d. g. (2005): an in tro duc tion to ap plied geos ta tis ti cs – part 7 – using se con da ry in for ma tion: co-kri gi ng. lec tu re no tes.– depar tme nt of ear th syste ms ana lysis, in ter na tio nal in sti tu te for geoin for ma tion scien ce & ear th ob ser va tion (itc) (http://www.itc. nl/personal/rossiter/teach/lecnotes.html#l6) (20 feb 2008). smoljanović, s. & malvić, t. (2005): impro ve men ts in re ser voir cha rac te ri za tion ap plyi ng geos ta tis ti cal mo del li ng (es ti ma tion & stoc has tic si mu la tio ns vs. stan da rd in ter po la tion met ho ds), ca se study from croa tia.– naf ta, 56/2, 57–63. šimon, j. & batušić, v. (1974): o li tos tra tig raf skom stu pu naf tnog po lja be ni čan ci [about lit hos tra tig rap hic sec tion of the oil fi e ld beni čan ci – in croatian]. – zbor nik ra do va i. god. znan stve nog sku pa i. sek ci je zsn hazu (opa ti ja 1973), 75–89. tišljar, j. (1993): se di men ta ry bo dies and de po si tional mo de ls for the mio ce ne pro du ci ng areas la dis lav ci, be ni čan ci and obod (croatia).– naf ta, 44/10, 531–542. turajlić, v., mateljak, m. & dević, t. (1979): us po red ni prikaz i prob le ma ti ka raz ra de le žiš ta naf tnih po lja be ni čan ci, obod i la dis lav ci – ku ča nci [paral lel re view and prob le ms in de ve lop ment of the oil fi e ld be ni čan ci, obod and la dis lav ci-ku čan ci]. – in croatian – zbor nik ra do va 3. god. nauč ni skup sek ci je za prim je nu geo lo gi ju, geo fi zi ku i geo ke mi ju znan stve nog sav je ta za naf tu, novi sad (1977), 2, 643–658. welhan, j. (2001): geo lo gy 606: geos ta tis ti cs and spa tial mo de li ng. sylla bus and cour se lec tu re no tes.– spri ng se mes ter 2001, ida ho sta te uni ver si ty, http://giscenter.isu.edu/training/ (20 feb 2008). xu, w., tran, t.t., srivastava, r.m. & journel, a.g. (1992): in teg ra ti ng seis mic da ta in re ser voir mo del li ng: the col lo ca ted cok ri gi ng al ter na ti ve.– spe pa per 24742. review paper manuscript received june 6, 2007. revised manuscript accepted january 18, 2008. 05 malvic.indd 4705 malvic.indd 47 24.6.2008 11:10:3124.6.2008 11:10:31 05 malvic.indd 4805 malvic.indd 48 24.6.2008 11:10:3224.6.2008 11:10:32 gui de for con tri bu to rs ori gi nal scien ti fi c pa pe rs dea li ng wi th eve ry as pe ct of ear th scien ces, es pe cial ly con cer ni ng the di na ri des, the ad ria tic/mediterranean re gion, pan no nian ba sin, and/or kar st is sues are con si de red for pub li ca tion in geo lo gia croa ti ca, as we ll as no tes and re views in te res ti ng to a wi der au dien ce (e.g. re view pa pe rs, book re views, no tes). ma nus crip ts shou ld be writ ten in en gli sh. for croa tian aut ho rs an ad di tio nal ab stra ct in croa tian may al so be in clu ded. ma nus crip ts elec tro nic ver sion of ma nus cri pt shou ld be se nt by e-mail to edi to rial.offi ce@geologia-croatica.hr. ad di tio nal ly, pa per co py of the ma nus cri pt ac com pa nied by co pies of all il lus tra tio ns shou ld be se nt to the geo lo gia croa ti ca, croa tian geo lo gi cal sur vey, sac hso va 2, p.o. box 268, hr-10000 zag reb, croa tia. ma nus cri pt shou ld be in doub le spa ced types cri pt wi th am ple mar gi ns. plea se, pro vi de ca re ful lan gua ge re vi sion be fo re sub mission of the ma nus cri pt. the tit le shou ld be in for ma ti ve, but sho rt, and shou ld be fol lowed by the com ple te fir st na mes and sur na mes of all aut ho rs. the fu ll pos tal and e-mail ad dres ses of the aut ho r(s) shou ld be gi ven at the bot tom of the fi r st pa ge. a brief in for ma ti ve abstra ct of 50–300 wor ds shou ld be in clu ded, as we ll as ca re ful ly cho sen key wor ds pro po sed by the aut hor(s). text the text shou ld be in wor dpro ces si ng fi le. we can not ac ce pt text and fi gu res in pdf for mat. we ac ce pt mo st wor dpro ces si ng for ma ts, but wo rd is pre fer red. always keep a bac kup co py of the elec tro nic fi le for re fe ren ce and sa fe ty. sa ve your fi les usi ng the de fau lt exten sion of the prog ram used. it is im por ta nt that the fi le be sa ved in the na ti ve for mat of the wor dpro ces sor used. the text shou ld be in sin gle-co lu mn for mat. keep the layout of the text as sim ple as pos sib le – most for mat ti ng co des wi ll be re mo ved and rep la ced on pro ces si ng the ar tic le. in par ti cu lar, do not use the wor dpro ces so r’s op tio ns to jus ti fy text or to hyphe na te wor ds. howe ver, do use bo ld fa ce, ita li cs, sub scrip ts, su per scrip ts etc. do not em bed ‘grap hi cal ly de sig ne d’ equa tio ns or tab les, but pre pa re the se usi ng the wor dpro ces so r’s fa ci li ty. the elec tro nic text shou ld be pre pa red in a way ve ry si mi lar to that of con ven tio nal ma nus crip ts. to avoid un ne ces sa ry er ro rs you are stron gly ad vi sed to use the ‘spel lchec ke r’ fun ction of your wor dpro ces sor. fi gu re cap tio ns and tab les pre se nt fi gu re cap tio ns and tab les at the end of the ar tic le. when pre pa ri ng tab les, if you are usi ng a tab le grid, use on ly one grid for ea ch in di vi dual tab le and not a grid for ea ch row. if no grid is used, use ta bs, not spa ces, to ali gn co lum ns. num ber tab les con se cu tive ly in ac cor dan ce wi th their ap pea ran ce in the text. pla ce foot no tes to tab les below the tab le bo dy and in di ca te them wi th su per scri pt lower ca se let te rs. avoid ver ti cal ru les. be spa ri ng in the use of tab les and en su re that the da ta pre sen ted in tab les do not dup li ca te re sul ts des cri bed el sewhe re in the ar tic le (in clu di ng fi gu res). grap hi cs a hi gh stan da rd of il lus tra tion qua li ty is de si red. ea ch il lus tra tion mu st ha ve a cap tion, whi ch is re le va nt and expla nato ry. cap tio ns shou ld be typed on se pa ra te shee ts. bar sca les are pre fer red. all il lus tra tio ns shou ld be num be red and the aut hor’s na me shou ld be writ ten on the ba ck of pa per co py in pen cil. the ap proxi ma te po si tion in the text may be in di ca ted in the mar gin of the ma nus cri pt. the maxi mum si ze of pla tes is 175 x 255 mm. the maxi mum wid th of il lus tra tio ns in the text (pho tog rap hs, tab les and drawin gs) is 80 mm (for one co lu mn) or 165 mm (for two co lum ns). for mo re than three pla tes, plea se con ta ct the edi to rs! hi gh-re so lu tion grap hi cs fi les mu st always be pro vi ded se pa ra te from the main text fi le. do not im po rt the fi gu res in to the text fi le, ju st in di ca te their ap proxi ma te lo ca tio ns di rec tly in the elec tro nic text and on the ma nus cri pt. ge ne ral poin ts • ma ke su re you use uni fo rm let te ri ng and si zi ng of all your ori gi nal ar two rk. • sa ve text in il lus tra tio ns as »cur ves« or en clo se the fo nt. • on ly use the fol lowi ng fon ts in your il lus tra tio ns: arial, hel ve ti ca, ti mes, symbol. • num ber the il lus tra tio ns ac cor di ng to their sequen ce in the text. • use a lo gi cal na mi ng con ven tion for your ar two rk fi les, and sup ply a se pa ra te lis ti ng of the fi les and the sof twa re used. • pro vi de cap tio ns to il lus tra tio ns se pa ra te ly. • pro du ce ima ges near to the de si red si ze of the prin ted ver sion. for ma ts re gar dle ss of the ap pli ca tion used, when your elec tro nic ar two rk is fi na li sed, plea se »sa ve as« or con ve rt the ima ges to one of the fol lowi ng for ma ts (no te the re so lu tion requi re men ts for li ne drawin gs, hal fto nes, and li ne/halftone com bi na tio ns gi ven be low.): eps: vec tor drawin gs. em bed the fo nt or sa ve the text as »grap hi cs«. tiff or hig he st-qua li ty jpeg – co lour or greysca le pho tog rap hs (hal fto ne s): fi gu re in the fi nal si ze shou ld ha ve a mi ni mum re solu tion of 300 dpi. 05 malvic.indd 4905 malvic.indd 49 24.6.2008 11:10:3224.6.2008 11:10:32 tiff or hig he st-qua li ty jpeg – bit map ped li ne drawin gs: fi gu re in the fi nal si ze shou ld ha ve a mi ni mum re so lu tion of 1000 dpi. tiff or hig he st-qua li ty jpeg – com bi na tio ns bit map ped li ne/half-tone (co lour or greysca le): fi gu re in the fi nal si ze shou ld ha ve a mi ni mum re so lu tion of 500 dpi. doc, xls or ppt: if your elec tro nic ar two rk is crea ted in any of the se mic ro so ft of fi ce ap pli ca tio ns plea se sup ply »as is«. plea se do not • sup ply em bed ded grap hi cs in your wor dpro ces sor (spread sheet, pre sen ta tion) do cu me nt when sub mit ti ng the fi nal ver sion of the ac cep ted ar tic le; • sup ply fi les that are op ti mi sed for screen use (li ke gif, bmp, pict, wpg); the re so lu tion is too low; • sup ply fi les that are too low in re so lu tion; • sub mit grap hi cs that are dis pro por tio na te ly lar ge for the con te nt. ge ne ra and spe cies na mes ge ne ra and spe cies na mes shou ld be writ ten in ita li cs, e.g. chrysa li di na gra da ta d’orbigny. ab bre via tio ns and uni ts si uni ts are pre fer red. all mea su re men ts shou ld always be gi ven in fi gu res, e.g. 12 m, exce pt whe re the num ber be-gi ns the sen ten ce. the wo rd »fi gu re« shou ld be shor te ned to »fig.« un le ss at the be gin ni ng of a sen ten ce. re fe ren ces re fe ren ces in text shou ld be lis ted by gi vi ng the aut hor’s sur na me (in ca pi tal let te rs) fol lowed by the year of pub li ca tion in pa ren theses, e.g. velić (2007) or korolija & jamičić (1988). when re fe ren ce is ma de to wo rk by mo re than two aut ho rs, the fi r st na me shou ld be fol lowed by »et al.«, e.g. reimann et al. (2008). if se ve ral pa pe rs by the sa me aut hor and from the sa me year are ci ted, a, b, c, etc. shou ld be put af ter the year of pub li ca tion, e.g. vrsaljko (2003b). com ple te re fe ren ces shou ld be lis ted in al pha be tical or der at the end of the pa per (aut ho rs mu st pro vi de en gli sh tran sla tio ns of ar tic le tit les writ ten in ot her lan gua ges), as in the fol lowi ng exam ples: fuček, l., jelaska, v., gušić, i., prtoljan, b. & oštrić, n. (1991): pa din ski tu ron ski se di men ti uva le br biš ni ca na du gom oto ku (tu ro nian slo pe de po si ts in the br biš ni ca co ve, du gi otok is la nd, croa tia – in croa tian). – geol. vjes nik, 44, 55–67. velić, i. (2007): stra tig rap hy and pa laeo bio geog rap hy of me so zoic ben thic fo ra mi ni fe ra of the kar st di na ri des (se eu ro pe). – geol. croat., 60, 1–113. korolija, b. & jamičić, d. (1988): os nov na geo loška kar ta sfrj 1:100000, li st našice (ba sic geo lo gi cal map of sfrj 1:100000, na ši ce sheet). – in st. za geol. is traž., zag reb, sav. geol. za vod, beog rad. palmer, a.n. (2006): di gi tal mo de li ng of kar st aqui fe rs – suc ces ses, fai lu res, and pro mis ses.– in: harmon, r.s. & wicks, c.m. (eds.): per spec ti ves on kar st geo mor pho lo gy, hydro lo gy, and geoc he mis try – a tri bu te vo lu me to de rek c. fo rd and wil liam b. whi te. the geo lo gi cal so cie ty of ame ri ca, spec. pa per 404, 243–250. reimann, c., filzmoser, p., garrett, r. & dutter, r. (2008): sta tis ti cal da ta ana lysis explai ned: ap plied en vi ron mental sta tis ti cs wi th r. – jo hn wi ley & so ns, new yo rk, lon don, 362 p. vrsaljko, d. (2003): bios tra tig ra fi ja mio cen skih nas la ga žum be rač kog i sa mo bor skog gor ja na te me lju me ku ša ca (bios tra tigrap hy of mio ce ne de po si ts from žum be rač ko and sa mo bor sko gor je mts. on the ba sis of mol lus cs – in croa tian, wi th an en gli sh ab stra ct). – un pu bl. phd the sis, fa cul ty of scien ce, uni ver si ty of zag reb, 147 p. un pub lis hed re por ts from in sti tu tion ar chi ves shou ld be ci ted in text as e.g. (andrić, 20012) and re fe red as foot no te. 2andrić, m. (2001): ro bin so n-du bo ka lju ta, seiz mič ka to mog raf ska mjerenja [ro bin zo n-du bo ka lju ta to mog rap hic mea su re men ts – in croatian]. – un pub lis hed re po rt, ar chi ve of ci vil en gi nee ri ng in sti tu te of croa tia, zag reb, 30 p. in ter na tio nal re view edi to rs fi r stly che ck ea ch ma nus cri pt for com plian ce wi th the jour nal stan dar ds. all ori gi nal scien ti fi c pa pe rs whi ch mig ht be pub lished in geo lo gia croa ti ca are then reviewed in ter na tio nal ly. the du ra tion of the re viewi ng pro ce ss is va riab le, de pen di ng on nu me rous fac to rs. we wi ll do our be st do re du ce it as mu ch as pos sib le. howe ver, typi cal ly the en ti re pro ce ss from sub mis sion of the fi r st ver sion of the ma nus cri pt to pub li ca tion ta kes 5 to 10 mon ths, and ca re ful fol lowi ng of this gui de for con tri bu to rs wi ll usual ly sig ni fi can tly dec rea se du ra tion of this pro ce ss. af ter re vi sion and cor rec tion of the ma nus cri pt has been com ple ted the aut hor shou ld pre pa re the fi nal ver sion of the ma nus cri pt, on ly in elec tro nic fo rm. this ver sion wi ll be se nt to the uni ted kin gdom to our lan gua ge edi tor, and on ly af ter this cor rec tion is do ne the ma nus cri pt is rea dy for pub li ca tion. pa ge proo fs pa ge proo fs wi ll be se nt to the aut ho rs. they shou ld be read ca re ful ly and re tur ned wit hin a week. of fprin ts twen ty fi ve of fprin ts of ea ch pa per and one vo lu me of the jour nal are sup plied free of char ge. ad di tio nal of fprin ts may be or de red. 05 malvic.indd 5005 malvic.indd 50 26.6.2008 9:23:5826.6.2008 9:23:58 geo.cro.2-3-61-kb.pdf 129 � felix schlagintweit1 and wolfgang pavlik2 ab stra ct two taxa of halimedacean algae are recorded from the upper triassic lagoonal dachstein limestone (norian-rhaetian) of the hochschwab area in the south-eastern part of the northern calcareous alps of austria. they are described in open nomenclature as halimeda? sp. 1 and halimeda? sp. 2. in contrast to the widespread occurrence of dasycladalean algae, representatives of halimedaceans are very rare. these fi ndings are the second record in the northern calcareous alps since flügel (1975). keywor ds: calcareous algae, halimedaceae, taxonomy, triassic, northern calcareous alps, austria 1 lerchenauerstr. 167, d-80935 münchen, germany; (ef.schlagintweit@t-online.de) 2 geologische bundesanstalt, neulinggasse 38, a-1030 wien, austria; (wolfgang.pavlik@geologie.ac.at) new fi ndings of halimedacean algae from the late triassic dachstein limestone of the northern calcareous alps (hochschwab area, styria, austria) geologia croatica 61/2–3 129–133 3 figs. zagreb 2008 geologia croaticageologia croatica � 1. introduction dasycladales (calcareous green algae), such as diplopores, are widespread in the middle and upper triassic limestones of the northern calcareous alps (e.g. pia, 1920; ott, 1967). they appear in “incredible abundance” and “were the halimeda of their time, ecologically speaking” (elliott, 1991, p. 127). although there is a variety of genera assigned to halimedacean algae with their fi rst records from the middle triassic as summarized recently by senowbari-daryan & zam parelli (2005), records of the genus halimeda lamouroux (or boueina toula) from the triassic are comparably rare worldwide, but also include one occurrence from the northern calcareous alps of austria (see further below). in fact, even in the 1960’s, the halimeda-boueina couplet wasn´t known to occur in the triassic, being fi rst known from the beginning of the jurassic (e.g. johnson, 1964). from the triassic, their disarticulated segments were reported predominantly from lagoonal limestones, whereas almost all other triassic halimedacean algae, often with bush-like growth forms, were described from reefal limestones (e.g. senowbaridaryan & zamparelli, 2005). flügel (1975) re port ed on the occurrence of boueina hochstetteri liasica le maitre from the norian-rhaetian dachstein limestone of the gosaukamm. later, the age of the boueina-bearing limestones was refi ned to the norian (flügel, 1988). from the norian-rha e tian of western thailand, flügel (1988) described the new species boueina marondei, also recently discovered from the upper triassic of iran (senowbari-daryan & ham a dani, 1999). two further species have been established in recent times by dragastan et al. (2000) from the rhaetian of hydra (greece) as halimeda helladica and halimeda discreta. in this work, boueina marondei flügel was treated as belonging to the genus halimeda. in conclusion, there are now up to four geographic records (austria, thailand, iran and greece) of localities of triassic representatives of the genera halimeda-boueina. geologia croatica geologia croatica 61/2–3 130 in the framework of a karst-hydrologic project, coordinated by the geological survey of austria (mandl1 et al., 2002) representatives of halimedaceans tentatively ascribed here to the genus halimeda lamouroux, 1812 were dis covered in two samples of late triassic limestones from the south-eastern part of the northern calcareous alps of austria (fig. 1). given the general rarity of triassic halimedaceans, these fi ndings are briefl y described here, and represent the second record in the northern calcareous alps since that of flügel (1975). 2. geological overview and material the muerztal alps of styria being part of the southeastern northern calcareous alps are dominated by middle and up per triassic limestones and dolomites (e.g. spengler, 1920; 1 mandl, g.w. (project leader), bryda, g., kreuss, o., moser, m., pavlik, w., decker, k., draxler, i., krystyn, l. & piros, o. (2002): erstellung moderner geologischer karten als grundlage für karsthydrogeologische spezialuntersuchungen im hochschwabgebiet: folgeprojekt eisenerz – schwabeltal – meßnerin – mitteralpe. forschungsprojekt wa-4a f2000 & sta028n/ f2000 der ma31 wiener wasserwerke, des amtes der steier märkischen landesregierung und des bundesministeriums f. bildung, wissenschaft & kultur. – unpubl. final report, projektzeitraum 1. juni 2000 – 31 mai 2002, 211 p., wien. lein, 2000; mandl et al., 2002). in the hochschwab area (or hochschwab unit) which forms part of the muerztal nap pe, wetterstein limestone (ladinian-middle carnian) and dach stein limestone (norian-rhaetian) are mostly prevalent. both lithostratigraphic units may comprise both reefal and la goonal facies. representatives of halimedaceae were ob served in two samples: sample wpa 61/98. this sample comes from the northern side of the grasberg (1673 m), (see the topographic map of austria 1:25.000 ök no. 101, eisenerz, coordinates 645935/ 277850). according to the geological map 1:25.000 in mandl et al. (2002), the grasberg is built up of lagoonal dachstein limestone (norian-rhaetian). the occurrence of the dasycladalean alga griphoporella curvata (gümbel) provides evi dence for a norian-rhaetian age (e.g. barattolo et al., 1993), thus confi rming assignation to the dachstein limestone. the microfacies represent a biosparite (grainto packstone). the sample contains halimeda? sp. 1, dasycladalean algae, gastropods, foraminifera, peloids and aggregate grains and can be referred to an open-marine platform. sample wpa 233/97. sample locality is situated south of the karlstein (2013 m) and southwest of the hundsboden, topographic map of austria 1:25.000 ök no. 102, afl enz kur ort, coordinates 656615/274660. in this area, the boundary between the wetterstein and dachstein limestones occurs. the microfacies represent a biosparite (grainstone). sample wpa 233/97 contains halimeda? sp. 2, calcareous algae, fi gu re 1: topographic map of sample locations wpa 61–98 and wpa 233–97 in the hochschwab area of the mürztal alps, austria. geologia croaticafelix schlagintweit and wolfgang pavlik: new fi ndings of halimedacean algae from the late triassic dachstein limestone... 131 gas tropods, remains of sphinctozoan sponges, crinoids, tubiphytes sp. and peloids. the sample can be refered to an open lagoon to back-reef facies. direct stratigraphic dating of sample wpa 233/97 is not possible; because of the overall fi eld relationships and samples taken from the immediate surroundings, it is also referred to the dachstein limestone. 3. taxonomic descriptions before starting with the description of the alpine material, some remarks on fossil halimedacean algae are vital. algae today referred to the halimedaceae (e.g. hillis, 1991) were formerly grouped within the codiaceae, then afterwards in the udoteaceae (e.g. bassoullet et al., 1983; mu, 1991, based on general morphology). extant halimeda species may show differences in the shape of the individual segments, and also segments from different parts of the plant may show variable numbers of utricle layers (e.g. dragastan et al., 2002). when referring these observations to fossil taxa, their correct determinations and descriptions become problematic. for instance, flügel (1975) remarked that differences in sizes of the thalli or siphons are not convenient for further splitting off the species boueina hochstetteri toula. in fact, as has been pointed out by dragastan et al. (2002) the description of some fossil taxa are based on poorly, sometimes even insuffi cient material. as an exception to this, the thorough morphological study of the turonian halimeda elliotti by conrad & rioult (1977) differing between individual-sized segments within one taxon should be highlighted. as a consequence, dragastan et al. (2002) synonymized a large number of the fossil “taxa” with recent representatives of halimeda. also, the genera arabicodium elliott, 1957 and boueina toula, 1884 were included within this halimeda concept and considered synonyms to halimeda. as a consequence, all four representatives reported from the triassic (b. hochstetteri liassica, b. marondei, h. helladica, h. dis creta, see introduction) were put in synonymy with halimeda cylindracea decaisne. this halimeda concept of dragastan et al. (2002) only deals with a reduced number of methusalemi species exhibiting extremely long stratigraphic ranges, e.g. about 220 million years for halimeda cylindracea. despite the aforementioned problems with fossil taxa, such a rigid taxonomic reconsideration is at least problematic without restudying the original materials, especially the biometric variabilities of the topo-type material, and additional abundant and well-preserved material. as a consequence of these problems concerning fossil material, hillis (2000, p. 189) concludes that “it seems prudent to maintain the status quo of the taxa (remark: halimeda, boueina, arabicodium)” for the moment being, as usually used by many workers (e.g. bucur, 1994). another point to mention is that in some cases a radical synonymization obscures certain im portant biostratigraphic occurrences (e.g. bucur, 1999, tab. 17), for instance in the upper triassic-liassic period. therefore, and also due to the fact that our material is strongly recrystallized, not allowing observation of some morphological details, descriptions here use open nomenclature as halimeda? sp. 1 and halimeda? sp. 2. we agree with many other workers, that the structural differentiation of halimeda, bou eina and arabicodium is too artifi cial and non-specifi c for a clear-cut separation of the three. thus, the open nomenclatural approach refers to the genus halimeda having priority as des cribed the earliest of the three. referring to only two thinsections for each species, with some segments in low abundance, statistical analysis of the morphometric parameters cannot be provided. moreover, detailed dimensions with res pect to the individual sizes of different siphon orders are not appropiate due to the comparably poor state of preservation, instead only the size ranges of the meduallar (dms) and cortical siphons (dcs) are indicated. outer segment diameters are indicated as d. fi gu re 2: halimeda? sp. 1. a) longitudinal section. b) longitudinal-oblique section. c) two fragments. sample wpa 233–97, scale bars = 2 mm. geologia croatica geologia croatica 61/2–3 132 family halimedaceae link, 1832 genus halimeda lamouroux, 1812 halimeda? sp. 1 (fig. 2a–c) description: thallus segments cylindrical, uncompressed, showing slightly undulating diameters. the poorly calcifi ed medulla amounts about 1/3 of the segment diameter. there are no remarkable differences between the diameters of the me dullary and fi rst order cortical siphons. higher order cortical siphons (up to 3–?4 series) become succesively reduced in their diameter. the cortical siphons continuously bend away from the axis. dimensions: d = 1.8–2.35 mm; dms = 0.038–0.067 mm; dcs = 0.02–0.05 mm. remarks: halimeda? sp. 1 is distinguished from halimeda? sp. 2 especially by the medullar zone composed of more loosely packed siphons not signifi cantly different in diameter from the cortical siphons. given that the fi ne medullary siphons are comparable to and not signifi cantly different from the cortical siphons, this taxon indicates an arabicodiumtype halimedacean alga if separation of the three different genera is accepted (see remarks above). halimeda? sp. 2 (fig. 3a–g) description: elongated-cylindrical segments (length up to 8 mm) showing constrictions at irregular distances (fig. 3e). cross-sections of segments are round. medullar zone making up 28–45 % of the total segment diameter, broad with numerous close-set fi laments, irregularly disposed. the medullar zone may be well calcifi ed (fig. 3a, f–g) but in other specimens appears as a sparitic central hollow (e.g. fig. 3b, c). spar-fi lled, interwoven medullar siphons are distinctly thicker than the cortical siphons, close-set leaving little intersiphonal space. each medullar siphon is surrounded by a thin micritic wall (fig. 3f–g). dimensions: d = 0.65–2.6 mm; dms = 0.06–0.15 mm; dcs = 0.03–0.05 mm remarks: halimeda? sp. 2 resembles halimeda helladica dragastan, kube & richter, 2000, from the rhaetian of greece, later put in synonymy with halimeda cylindracea by dragastan et al. (2002). halimeda? sp. 2 is clearly separated from halimeda? sp. 1 above all by the coarser and closer packed medularry siphons. fi gu re 3: halimeda? sp. 2. a) transverse section (below) and oblique transverse section of griphoporella curvata (gümbel) (above). b) two segments in oblique transverse sections. c) oblique section. d) longitudinal-oblique section. e) longitudinal section showing segment constrictions. f ) fragmentary longitudinal section showing coarse and close-packed medullary siphons. g) fragmentary oblique section. sample wpa 61–98, scale bars = 1 mm. geologia croaticafelix schlagintweit and wolfgang pavlik: new fi ndings of halimedacean algae from the late triassic dachstein limestone... 133 acknowledgement we sincerely thank olga (budapest) for the determination of the dasycladales, the vienna waterworks and the federal ministry for science and research for their fi nancial support of the karst-hydrologic project. helpful comments provided by reviewers ioan bucur (cluj-napoca) and ovidiu dragastan (bucharest) are kindly acknowledged. references barattolo, f., de castro, p. & parente, m. (1993): some remarks on griphoporella curvata (gümbel 1872) pia 1915, dasycladacean green alga from the upper triassic. – boll. soc. paleont. ital., spec. vol. 1, 23–45. bassoullet, j.-p., bernier, p., deloffre, r., génot, p., poncet, j. & roux, a. (1983): les algues udoteacées du paléozoique au cénozoique. – bull. centres rech. explor. –prod. elf-aquitaine, 7/2, 449–621. bucur, i.i. (1994): lower cretaceous halimedaceae and gymnocodiaceae from southern carpathians and apuseni mountains (romania) and the systematic position of the gymnocodiaceae. – beitr. paläontol., 19, 13–37. bucur, i.i. (1999): stratigraphic signifi cance of some skeletal algae (dasycladales, caulerpales) of the phanerozoic. – palaeoplagos, spec. pub. 2, 53–104. conrad, m. & rioult, m. (1977): halimeda elliotti nov. sp., algue calcaire (chlorophyceae) du turonien des alpes-maritimes (s.e. france). – géol. méditer., 4/2, 83–96. dragastan, o., kube, b. & richter, d.k. (2000): new late triassic calcareous algae from hydra, greece. – acta palaeont. romaniae, 2 (1999), 139–156. dragastan o., littler, d. s. & littler, m. m. (2002): recent vs. fossil halimeda species of angaur island, palau and adjacent western pacifi c areas. – acta palaeont. romaniae, spec. pub. 1, 3–20. elliott, g.f. (1957): new calcareous algae from the arabian peninsula. – micropaleontology, 3/3, 227–230. elliott, g.f. (1991): dasycladalean algae of the palaeozoic and mesozoic. – in: riding, r. (ed.): calcareous algae and stromatolites. springer, berlin, 125–130. flügel, e. (1975): kalkalgen aus riffkomplexen der alpin-mediterranen obertrias. – verhandl. geol. b.-a., 1974/2–3, 297–346. flügel, e. (1988): halimeda: paleontological record and palaeoenvironmental signifi cance. – coral reefs, 6 (1988), 123–130. hillis, l.w. (1991): recent calcifi ed halimedacea. – in: riding, r. (ed.): calcareous algae and stromatolites. springer, berlin, 167– 188. hillis, l.w. (2000): phylogeny of halimeda (bryopsidales): linking palaeontological, morphological and molecular data. – acta palaeont. romaniae, 2 (1999), 183–189. johnson, j.h. (1964): the jurassic algae. – quart. colorado school of mines, 59/2, 1–129. lamouroux, j. (1812): classifi cation des polypiers coralligènes on entièrement pierreux. – nouv. bull. soc. philom, 3, 181–188. lein, r. (2000): die hallstätter trias der mürztaler alpen. – mitt. ges. geol. bergbaustud. österr., 41, 289–296. mu, x. (1991): fossil udoteaceae and gymnocodiaceae. – in: riding, r. (ed.): calcareous algae and stromatolites. springer, berlin, 146– 166. ott, e. (1967): dasycladaceen (kalkalgen) aus der nordalpinen obertrias. – mitteilungen der bayerischen staatssammlung für paläontologie und historische geologie, 7, 205–226. pia, j. von (1920): die siphoneae verticillatae vom karbon bis zur kreide. – abh. zool.-bot. ges. wien, 11/2, 1–259. senowbari-daryan, b. & hamadani, a. (1999): girvanella coated udoteacean oncoids from the upper triassic (norian-rhaetian) nayband formation, south of abadeh (central iran). – rev. paléobiol., 18/2, 597–606. senowbari-daryan, b. & zamparelli, v. (2005): triassic halimedaceans: new genera and species from the alps, sicily and southern apennines. – rev. espan. micropaleont., 37/1, 141–169. spengler, e. (1920): zur stratigraphie und tektonik der hochschwabgruppe. – verh. geol. st.-a., 1920, 49–60. toula, f. (1884): geologische untersuchungen im westlichen theile des balkan und in den angrenzenden gebieten. (x) von pernik nach sofi a, auf den vitos, über pernik nach trn und über stol nach pirot.sitzungsber. – k. akad. wiss. wien, 88/3-5, 1279–1348. manuscript received february 18, 2008 revised manuscript accepted may 19, 2008 geo.cro.2-3-61-kb.pdf 273 � 1. introduction in the izmir region (western turkey) near bornova, mesozoic rocks are represented by the “wildfl ysch” zone of the taurids consisting of a maastrichtian-danian sandy-shaly matrix with late triassic to late cretaceous carbonate megablocks. previous work on the mesozoic carbonates has been carried out by akdeniz et al. (1986), erdoğan (1990) and isintek et al. (2000). akdeniz et al. (1986) noted a thick carbonate sequence of late cretaceous age, tectonically overlying the late cretaceous clastics. erdoğan (1990) reported that the late triassic to late cretaceous limestone masses in question were allochthonous blocks in the so-called “bornova melange” of maastrichtian-danian age. according to erdoğan (1990) the carbonate block lying between the village of naldöken and çiçekli consists of jurassic to upper cretaceous deposits, including an albian bauxite lens north of naldöken (fig. 1). recently the presence of a second bauxite bearing horizon in the barremian part of the upper limestone unit has been documented ne of naldöken (fig. 2). the izmirella-bearing limestones are exposed in the socalled “bornova-block” located between naldöken and çiçekli (1:25.000, izmir – l18 – b1 sheet; figs. 1, 2). the studied cretaceous deposits, north of naldöken, are represented by a thick sequence of lagoonal, subtidal to supratidal limestones, barremian–lower aptian in age and including a bauxite horizon. the type section of the izmirella-bearing limestones is located 250 m east of the hendilagili ridge, 2.7 km to the northeast of naldöken (figs. 1b, 2), and consists of a grey, thick bedded limestone sequence about 30 m thick (fig. 3). the basal part of the section (about 10 m thick) consists of thick-bedded peloidal micrite and/or peloidal sparry facies, including laminated fenestral structures, intercalated with terrestrial lime clays and palaeosols. the middle part of the section is made up of well bedded or nodular micritic and/or sparitic limestones, sometimes laminated, with pebbly or clayey micrite associated with early erosional surfaces. the clayey micritic limestones include rare foraminifera, gastropods, ostracods, faecal pellets, salpingobaba senowbari-daryan1 and ismail isintek2 ab stra ct izmirella cretacea nov. gen., nov. sp., a complex alga, forming microbioherms is described from barremian – aptian platform carbonates of the “bornova block”, an allodapic unit derived from the northern margin of the menderes massif, included in maastrichian – danian fl ysh deposits, called the “bornova melange”. the verticillate thallus of this alga consists of strongly imbricated bowlto funnel-shaped whorls having tightly stacked laterals with two layers. the fi rst is composed of radially and fan-like running segments, appearing as large cells in section parallel to the growth direction. the second is composed of multibranched tubes, running perpendicular to the segments of the fi rst layer. besides its organizational traits, this has original calcite mineralogy and an aggregative behaviour leading to the formation of laminated build-ups closely resembling stromatolitic bioconstructions or even stromatoporoids. keywor ds: algae, izmirella, cretaceous, izmir, turkey 1 geozentrum nordbayern, university of erlangen-nürnberg, loewenichstr. 28, d-91054 erlangen, germany; (basendar@uni-erlangen.de) 2 department of geological engineering, engineering faculty, dokuz eylul university, 35100 bornova, izmir, turkey; (ismail.isintek@deu.edu.tr) izmirella cretacea nov. gen., nov. sp., a complex alga from the lower cretaceous, ne of bornova-izmir/turkey geologia croatica 61/2–3 273–295 10 figs. 7 pls. zagreb 2008 geologia croaticageologia croatica � geologia croatica geologia croatica 61/2–3 274 fi gu re 1: location map of the study area in western turkey; (a) geological map of the bornova area; (b) the position of the izmirella nov. gen. bearing site (simplifi ed after erdoğan, 1990). fi gu re 2: detailed geological map of the mesozoic carbonates of the “bornova block” in the area of the type locality of izmirella nov. gen. geologia croaticababa senowbari-daryan and ismail isintek: izmirella cretacea nov. gen., nov. sp., a complex alga from the lower cretaceous... 275 fi gu re 3: type section of the izmirella cretacea nov. gen., nov. sp. bearing limestone, in the upper limestone unit of the “bornova block”. geologia croatica geologia croatica 61/2–3 276 porella (hensonella?) dinarica radoičić, large (2–25 cm) fragments of izmirella microbioherms. salpingoporella (hensonella?) dinarica radoičić is a paleobiogeographic marker of the mediterranean southern tethyan margin (peybernes & conrad, 1979), and has been reported from beds ranging from the valanginian(?) (schindler & conrad, 1994) or from the tithonian?–berriasian (granier, 2002) to late aptian (velić & sokač, 1983). its acme is in the barremian–lower aptian (luperto sinni & masse, 1993). the upper part of the type section with izmirella cretacea nov. gen., nov. sp. is characterized by bioturbated, thick bedded or laminated micritic and/or intra-pelsparitic limestone with laminated fenestral structures, and thick bedded nodular micritic limestone. 2. systematic palaeontology alga incertae sedis genus izmirella nov. gen. derivatio nominis: after the city of izmir, close to which the alga was found. diagnosis: thallus segmented, composed of strongly imbricated bowlto funnel-shape whorls, each with tightly stacked, septate laterals. laterals, appearing as an oval or rectangular cell layer in sections, are divided radially several times towards the periphery of the whorls. a multibranched cell layer originates from the upper surface of the laterals, forming a second layer of whorls. a third layer consisting of “chaotic” tubes is located between the individual layers of the thallus. calcifi cation was originally calcitic. the organism grew with successive rows of closely packed individuals forming domal, laminated thalli resembling stromatolites or even stromatoporoids. type species: izmirella cretacea nov. sp. izmirella cretacea nov. sp. (figs. 4–10; pls. 1–7) derivatio nominis: after the occurrence of the alga in the cretaceous deposits. holotype: longitudinal section illustrated in pl. 4, fig. 1. isotypes: all specimens illustrated in pls. 1–7. locus typicus: 2.7 km northeast of naldöken, 250 m east of hendilagili ridge, karaburun/turkey (see figs. 1–2). stratum typicum: lower cretaceous (bar remi an–aptian) diagnosis: because of the monospecifi c character of the alga, the species diagnosis corresponds to the diagnosis of the genus. material: four microbioherms contain numerous hemispherical laminae. from one microbioherm containing the holotype (pl. 4, fig. 1) three large thin sections (10´15 cm) and from the second microbioherm two large thin sections were made. depository: the holotype (5 thin sections and 4 rock pieces) and illustrated paratypes are kept in the forschungsinstitut und naturmuseum senckenberg/frankfurt a. m., germany, inventary-nr: microbioherm of holotype (rockpieces: sm.b. 20863/a–c, thin sections illustrated in pls. 1–4: sm.b. 20863a/1, 20863b/1, 20863c/1, 20863d/1, 20863e/1), and one paratype sm.b. 20864 illustrated in pl. 5. description of microbioherms izmirella cretacea nov. gen., nov. sp. forms bioconstructed bodies up to 22 cm high which resemble stromatolites or stromatoporoid sponges with distinct laminations (pl. 1, figs. 1– 4; pl. 2, figs. 1–2; pl. 3, fig. 1). the individual laminae (layers) of the outside of the bioherms correspond internally to the individual rows, which are formed by numerous thalli of iz mirella cretacea arranged one beside the other (pl. 2, figs. 1–2). in thin sections, individual laminae are separated by dark horizons, usually thinner than the layers of izmirella rows (pl. 2, figs. 1–2). these dark horizons are composed of small and multibranched tubes of “chaotic” arrangement (pl. 5, figs. 5, 8) resembling girvanella. these tubes will be described in detail under the description of izmirella. the microbioherm containing the holotype is tabular, up to 7 cm thick with a height of 14 cm and a lateral extent of 21 cm (before cutting). another microbioherm (pl. 1, figs. 1–4), showing the height (figs. 1–2), thickness (fig. 3) and lateral extension (figs. 1–2), is also tabular, reaching 5.5 cm thickness, 22 cm height and 22 cm width. the microbioherm containing the holotype exhibits the well-developed lamination on one side only but the paratype, illustrated in pl. 1 shows well developed lamination on both sides. the base of this microbioherm is bulbous and shows several circular shaped initial parts of individual thalli of izmirella, having a diameter of approximately 2 mm. each basal bulb consists of the individual thalli of izmirella cut in cross section (see pl. 2, fig. 1 upper part of the photograph). the outer surfaces of all four available microbioherms are lamellar. the height of individual laminae is almost constant (about 3 mm, rarely varying between 2 mm and 5 mm). the laminae in the basal part of two microbioherms extend laterally, parallel to the substrate but in the younger part they are almost sub-spherical. in the third microbioherm the laminae at the top also extend parallel to the substrate (pl. 1, figs. 1–2). this specimen seems to be broken at both sides. the top of all microbioherms are vaulted. description of izmirella cretacea nov. gen., nov. sp. three large thin sections (10x15 cm, two parallel and one transverse to the growth direction) were cut into the microbioherm containing the holotype. two large thin sections were made from the second microbioherm. the longitudinal sections show (as recognizable from the outside), the layers (laminae) reaching a height of about 3 mm (pl. 1, figs. 1–4; pl. 2, figs. 1–2; pl. 3, fig. 1). each laminae is composed of numerous thalli of izmirella, arranged in rows one beside the other (pl. 2, figs. 1–2; pl. 3, fig. 2). adjacent thalli are in contact (especially at their lower and middle parts), but they never amalgamate laterally. individual thalli reach a diameter of 2.5–4.5 mm (pl. 3, figs. 2–4; pl. 4, figs. 1, 4, 6; pl. 5, fig. 1, 3; pl. 6, figs. 1, 4). most thalli have the same length corresponding to the height of laminae. geologia croaticababa senowbari-daryan and ismail isintek: izmirella cretacea nov. gen., nov. sp., a complex alga from the lower cretaceous... 277 each thallus is composed of numerous soup-plateor bowlto v-shaped elements or segments (pl. 2, figs. 1–2; pl. 3, figs. 2–4; pl. 4, figs. 1–2, 4–5; pl. 5, figs. 1, 3; pl. 6, fig. 1, 4), termed whorls in this paper. the whorls are fi tted one above the other. at the basal part of the thalli, the individual whorls are usually soup-plate-like, at the middle they become more bowl-like, at the upper part the whorls are mostly vshaped in section with a wide collar (pl. 3, fig. 3; pl. 4, figs. 1, 4–5), u-shaped (pl. 3, fig. 4), or even cup-shaped (pl. 6, figs. 1, 4, 8). in some specimens the bowl-shaped whorls of the middle part are less steep and resemble the soup-plate shaped whorls of the basal part, which they partly overlap (pl. 5, fig. 3). the inside of the youngest whorl is fi lled with either secondary calcite cement (pl. 2, figs. 1–2; pl. 3, fig. 2; pl. 7, fig. 7) or a micritic fi lm which covers the inside of the whorl (pl. 3, fig. 4). micrite also fi lled part of the inside of the whorl (pl. 4, fig. 2; pl. 6, figs. 4, 8). the micritic fi llings do not show any geopetal fabric and are interpreted to be of organic origin. spherical elements of about 50 µm in diameter were observed within this micritic mass (pl. 6, fig. 12). interpretation of these spherical elements as reproductive organs (gametangia) is very speculative. in longitudinal sections (parallel to the axis of the thallus) the individual whorls exhibit two layers of “cell-like” structures (pl. 4, figs. 2–3, 5–6; pl. 5, figs. 1–4, 6; fig. 4). the basal layer is composed of “large cells” corresponding with what we assume to be “laterals” (analogous to the thallus organization of dasyclad algae) cut in cross sections, arranged radially and running from the centre to the periphery of the whorls, similar to recent acetabularia (pl. 3, figs. 5–6; pl. 4, figs. 2–3, 5–7; pl. 5, figs. 1–4, 7; pl. 6, figs. 2–3, 5, 10–11, 13; pl. 7, figs. 1–2.). in cross section, the outline of the laterals (“large cells”) is oval to quadratic in shape, normally 80x40 µm directly around the axial column, termed here as the “axial stem” (pl. 4, figs. 2–3, 6; pl. 5, figs. 1, 3, 6; pl. 6, figs. 2, 5; fig. 4 marked with number 1). as observed in tangential sections, the laterals are divided several times toward the periphery of the whorls, by a zig-zag (wavy), thin wall (pl. 3, figs. 5–6; pl. 4, fig. 7; pl. 5, figs. 1–3, 7; pl. 6, figs. 10–11, 13; pl. 7, figs. 1–2; figs. 5–6). at least fi ve divisions and six orders of laterals were commonly observed (fig. 7). as shown in fig. 7, the levels where the laterals divide are not exactly at the same horizons. the divided pattern of the “laterals” of izmirella resembles some porostromate calcareous algae, like hedstroemia, selonopora or palaeozoic genera including botomaella or halysis (compare riding & voronova, 1985, fi g. 6; munnecke et al., 2001, fi g. 9; flügel, 2004, pl. 98, fi g. 2). such dichotomy of the “laterals” was also observed in the dasycladalean genus campbelliella (see de castro, 1993, pl. 13). the second layer, which appears darker in transmitted light, is developed above the fi rst and is composed of tubes originating from the upper surface of the laterals (pl. 4, figs. 3, 6; pl. 5, figs. 2, 4; pl. 7, fig. 1). if the section passes through the upper surface of the laterals, they appear as a plate of pores, refl ecting the cross sections of the tubes (pl. 3, figs. 5–6; pl. 7, fig. 1; figs. 4, 6). we term this layer with its corresponding tubes as “tubes of the second layer”, interpreted as having originated by multi-branching from different portions of the “laterals” (pl. 4, figs. 3, 6; pl. 5, figs. 1–4; pl. 6, fig. 6). the transverse outline of these “tubes” is usually polygonal, or somewhat circular, with a diameter of approximately 10 µm (pl. 5, figs. 2, 4, 6,). the resulting pattern consists of a layer of tubes between two layers of laterals (pl. 4, figs. 2, 3, 6; pl. 5, figs. 1–4, 6; pl. 6, fig. 3; pl. 7, figs. 1, 7–8), which represent off shoots? of izmirella and may be erroneously interpreted as representing another alga. as mentioned above, the darker horizons between the individual laminae (pl. 2, figs. 1–2; pl. 3, fig. 1) are composed of a “chaotic” cell layer, similar to girvanella (pl. 4, fig. 7; pl. 5, figs. 5, 8). as observed in several specimens, the edge of the last whorl becomes trumpet-like from which the “chaotic” fi gu re 4: section through three layers of laterals appearing white in thin sections (1) and three layers of tubes of second layers appearing dark in thin sections (2). the upper right corner of the photograph corresponds to the upper surface of laterals, from which the tubes of second layer (2) originate. the centre of the thallus is located in the ne, outside of the drawing. redrawn from pl. 5, fig. 2. fi gu re 5: section exhibiting the radiating branching pattern of the laterals from the axial stem. from seven laterals at the base (from the “axial stem”), about 40 laterals originate in the periphery of the whorl. geologia croatica geologia croatica 61/2–3 278 plate 1 1–4: microbioherm (paratype) formed by izmirella cretacea nov. gen., nov. sp. scale: 1 cm. 1 view of the “front-side” of a paratype showing the well-developed wavy laminae oriented parallel to the substrate (for magnifi cation of laminae see fi g. 4). 2 view of the other side (“back-side”) of the same specimen illustrated in fi g. 1. 3 side-view of the same specimen illustrated in fi g. 1 or fi g. 2. 4 magnifi ed part from fig. 1 (quadrangle marked with white line) shows details of the lamination. geologia croaticababa senowbari-daryan and ismail isintek: izmirella cretacea nov. gen., nov. sp., a complex alga from the lower cretaceous... 279 geologia croatica geologia croatica 61/2–3 280 plate 2 1–2: izmirella cretacea nov. gen., nov. sp. 1 magnifi cation from thin section 1q (transverse to oblique section) showing three layers (correspond to the laminae, separated by dark area containing “chaotic tubes”) in which the individual thalli are arranged in rows one beside the other. in the lower part of the photograph the thalli are cut in longitudinal section exhibiting the individual soup-plate-, bowlor funnel-shaped whorls arranged one above the other. at the upper part of the photograph the thalli are cut obliquely or transversely, exhibiting the circular outline of the whorls in cross section. 2 magnifi cation from thin section 1/l showing the rows (layers or laminae), in which the individual thalli are arranged one beside the other. the dark areas between the layers of adjacent thalli contain small “chaotic tubes”. the youngest whorl of the thallus is usually fi lled with calcite cement. geologia croaticababa senowbari-daryan and ismail isintek: izmirella cretacea nov. gen., nov. sp., a complex alga from the lower cretaceous... 281 geologia croatica geologia croatica 61/2–3 282 plate 3 1–7: izmirella cretacea nov. gen., nov. sp. scale in fig. 1 is 2 cm, in all others 1 mm. 1 longitudinal section (parallel to the growth direction) of a microbioherm containing the holotype (see pl. 4, fig. 1) exhibits the individual layers (laminae) composed of numerous thalli of izmirella arranged in rows one beside the other in horizontal direction (thin section 1/l). 2 magnifi cation from fi g. 1 showing several thalli with bowlor funnel-shaped whorls. the interior of the last whorl is usually fi lled with calcite cement. thin section1/1. 3 magnifi cation from fi g. 1. view of a thallus showing the plate-like and relatively broad whorls at the lower part (right in photograph) and v-shaped whorls at the upper part (left in photograph) of a thallus. thin section 1/1. 4 section through the younger part of a thallus that exhibits the cup-shaped last whorl. from the upper part of the youngest whorl there appears to arise a new whorl or a new thallus(?). the interior of the last whorl is covered by micrite of organic origin; the remainder is fi lled with calcite cement (for details see fig. 10). 5 longitudinal section through a thallus showing the “laterals” of the fi rst order (small arrows), branching to the “laterals” of the second and higher orders. the large triangular arrows indicate the radially arranged “laterals” of the fourth order. the medium-sized triangular arrows indicate the polygonal outline of the “tubes of the second layer” running perpendicular to the “laterals” of fi rst and second order. the small triangular arrow indicates the axial stem connecting the individual whorls. the large arrows at the left of the photograph indicate the branching pattern of the “tubes of the second layer” from the upper part of the “laterals”. note the wavy (zig-zag-like) wall between the “laterals” of fi rst and second orders (compare fi g. 7). thin section 1/1. 6 similar to fi g. 5. longitudinal section through four whorls exhibiting alternating “laterals” and the polygonal outline of the “tubes of the second layer” which are cut in transverse section and run perpendicular to the “laterals”. note the wavy (zig-zag-like) wall between the “laterals”. thin section l/q. 7 section exhibiting the edge of the last whorl of a broad, trumpet-like form, from which the tubes of the second layer originate (for details see fig. 8). geologia croaticababa senowbari-daryan and ismail isintek: izmirella cretacea nov. gen., nov. sp., a complex alga from the lower cretaceous... 283 geologia croatica geologia croatica 61/2–3 284 plate 4 1–7: izmirella cretacea nov. gen., nov. sp. all fi gures are from the same microbioherm as the holotype (thin section 1/l, pl. 3, fig. 1). scale in all fi gures 1 mm. 1 holotype. axial longitudinal section showing numerous soup-plate to bowlto funnel-shaped whorls. the narrow axial stem is cut in the upper and lower parts of the whorl. thin section 1/1. 2 section through a thallus exhibiting several whorls with the axial stem cut in the centre of the last four whorls. tubes of the second order, originating from the edges of the last whorl, extend bridge-like between the edges of the last whorl. the interior of the last whorl is covered by micritic layer (black) of organic origin. “up” is toward the left. 3 magnifi cation of several whorls showing the “laterals” (appearing as large cells) passing to the small, branched tubes (“tubes of second layer”) which have arisen from the laterals of fi rst order (arrow). “up” is toward the left. 4 magnifi cation of a thallus showing the bowl-like whorls at the lower part (right in photograph) and funnelor vshaped at the upper part (left in photograph) of a thallus. the small arrow indicates the radially arranged and fanlike multibranched tubes of the fi rst order of “laterals” (longitudinal section). “up” is toward the left. 5 the “laterals” of the fi rst and second order are recognizable in the last funnel-shaped whorl. the axial stem is cut in the centre of the preceding three whorls. “up” is toward the left. 6 similar to fi g. 5. the large arrows indicate the branching pattern of the “tubes of the second layer” and the triangular arrow points to the branching of a “tube of the second layer”. 7 transverse to oblique section through several whorls. the arrows indicate to the fan-like radially branched fi rst, second and third order “laterals”. geologia croaticababa senowbari-daryan and ismail isintek: izmirella cretacea nov. gen., nov. sp., a complex alga from the lower cretaceous... 285 geologia croatica geologia croatica 61/2–3 286 plate 5 1–8: izmirella cretacea nov. gen. nov. sp. from the third microbioherm. scale in fi gs. 1 and 3 is 0.5 mm, in fi g. 6 is 0.1 mm, in all others 0.2 mm. 1 section through several whorls of a thallus exhibiting the laterals and the tube layers of second order. the laterals appear as rectangular cells in the middle part, becoming oval and tube-like to the periphery of the whorls. the fanlike branching of the laterals is recognizable in the last whorl (for details see fi gs. 2, 4). 2 magnifi cation from fi g. 1 shows the details of three whorls with laterals (light area) and the tubes of a second layer (dark area). the fan-like branching of the laterals of the last whorl is clearly recognizable. the dark area with some pores at the last whorl (upper right) shows the boundary between the laterals and tubes of the second layer. arrows indicate the origin of the tubes of the second layer from the laterals (for details see fig. 4). 3 section through the upper part of a thallus exhibiting individual whorls running down and covering the old whorls. the axial stem is cut at the upper part, continuing to the fan-like branched laterals. 4 similar section to fi g. 2 showing the same characteristics. arrows indicate the detailed origin of the tubes of the second layer. 5 cluster of “chaotic” cells originating from the laterals (white area with large “cells”). 6 two “cell” layers of laterals (large “cells”) and tubes of the second layer (small “cells”) in an isolated fragment of a thallus. 7 fan-like branching of the laterals as shown in fi g. 7. 8 formation of “chaotic” tubes from the second layer (2) of the whorl. white “line” (1) indicates the laterals. arrow indicates the origin of the “chaotic” tubes. c = the cavity within the “chaotic” tubes. geologia croaticababa senowbari-daryan and ismail isintek: izmirella cretacea nov. gen., nov. sp., a complex alga from the lower cretaceous... 287 geologia croatica geologia croatica 61/2–3 288 plate 6 1–13: izmirella cretacea nov. gen. nov. sp. from the third microbioherm. 1 section through two thalli each with numerous whorls. the interior of the last whorl in the thallus on the left is fi lled with calcite cement. the axial stem is cut in the lower part of the thallus on the right. for details see fi g. 2. 2 magnifi cation of the area in fi g. 1, marked with white rectangle, showing numerous whorls with the laterals appearing as rectangular cells (lower part) adjacent to the axial stem. the axial stem passes through the whorls and branches at the upper most part (see fi g. 3). 3 magnifi cation of the upper most part of the axial stem in fi g. 2 showing the branching pattern. the laterals appear gray (partly as a cell layer); the tubes of the second layer are darker. small arrows indicate the branched tubes of the second layer. 4 section through a thallus with a cup-shaped fi nal whorl. the edge of the last whorl (quadrangle, see fi g. 7) expands (trumpet-like), with the later rejuvenation above. the interior of the last whorl is fi lled partly with micrite (gray) of organic origin. numerous small spherical elements (gametangia?, barely recognizable, see fi g. 12) are embedded within the micritic fi lling. 5 section from the upper part of a thallus showing the laterals and the branching pattern of the axial stem at the upper end of the thallus (for details see fi g. 6). 6 magnifi cation of fi g. 5 showing the details of the axial stem. 7 magnifi cation from fi g. 4 (quadrangle) showing the trumpet-like broadening of the upper end of the last whorl. 8 section through the upper part of a thallus showing the interior of the last whorl fi lled partly by micrite (gray) of organic origin and partly by cement (white). numerous spherical elements (gametangia?) are embedded within the micritic fi lling. cluster of tubes (appearing as cells) connect (like a bridge) the outer edges of the last whorl (for details see fi g. 9 and 12). 9 magnifi cation of part of fi g. 8, (large rectangle) of cells originating from one end of the whorl connecting both edges of the last whorl. 10 cross section through two thalli showing the last whorls appearing concentric (bulbous) with numerous laterals. arrow indicates the details of the last whorl in fi g. 11. 11 magnifi cation from fi g. 10 (arrow) showing the rejuvenation (?) of a whorl from a lateral and the branching pattern of the laterals. 12 magnifi cation from fi g. 8 (small rectangle) shows the tubes (right in photograph) and numerous spherical elements (gamentangia?) within the micrite infi lling. 13 magnifi cation of the upper part of the specimen illustrated in pl. 5, fig. 3 showing the origin of the whorls and laterals from the axial stem (white area) and the tubes of the second layer that originated from the laterals (dark area). geologia croaticababa senowbari-daryan and ismail isintek: izmirella cretacea nov. gen., nov. sp., a complex alga from the lower cretaceous... 289 geologia croatica geologia croatica 61/2–3 290 plate 7 1–8: sem-photomicrographs from diff erent parts of izmirella cretacea nov. gen., nov. sp. 1 section through three layers of laterals and tubes in a second layer. white arrows indicate the tube-like laterals. tubes of the second layer originate from the “pores”, in the upper surface of laterals. for magnifi cation of the area marked with rectangle marked see fi g. 2. “up” is toward the left. 2 magnifi cation from fi g. 1 (rectangle) showing the inside of laterals fi lled with large calcite crystals (arrows) and the wall of the laterals characterized by microgranular micritic crystals. for magnifi cation of the area marked with a rectangle see fi g, 3. “up” is toward the left. 3 magnifi cation from fi g. 2 showing the laterals, characterized by large crystals, and the wall characterized by microgranular structure of the crystals. “up” is toward the left. 4 magnifi cation from fi g. 7 showing the laterals with large crystals. arrows indicate the wall of laterals branching to the tubes of the second layer. “up” is toward the left. 5 similar to fi g. 3. “up” is toward the left. 6 the interior of laterals is characterized by large crystals and the walls (arrows) by microgranular structure. the area within the dots points to the tubes of the second layer that originated from one lateral. “up” is toward the left. 7 sem-view of alternating laterals (large crystals) and tubes of the second layer (small crystals). arrow indicates the last whorl fi lled with calcite cement. “up” is toward the left. 8 alternation of laterals and tubes of second layer. arrows indicate their boundaries. “up” is toward the left. geologia croaticababa senowbari-daryan and ismail isintek: izmirella cretacea nov. gen., nov. sp., a complex alga from the lower cretaceous... 291 geologia croatica geologia croatica 61/2–3 292 girvanella-like tube layer originates (pl. 3, fig. 4; pl. 5, figs. 5, 8; pl. 6, figs. 4, 7; fig. 8). the edges of the last whorl in some specimens are connected by a layer of tubes, forming a lid (appearing as a bridge between the edges) covering the top of the whorl (pl. 3, fig. 4; pl. 4, fig. 2; pl. 6, figs. 8–9; figs. 9–10). apparently the repetitive settlement of the alga results from these tube layers originating from the edges or lids of the last whorl. in most cases one or several calcite-fi lled cavities were observed within the clusters of the “chaotic” girvanella-like tubes (pl. 5, fig. 8). interpretation of these cavities as conceptacles is very speculative. the most peculiar part of this alga is the axial stem connecting the whorls of the thallus (pl. 4, figs. 1–2, 5; pl. 5, fig. 3; pl. 6, figs. 1–6, 10–11, 13). the axial stem is very narrow (less than 1 mm; usually 0.40–0.80 mm). numerous sections show that the axial stem is a part of this alga and can not be interpreted as a boring or as an interaction between the alga and another organism (symbiosis or commensalism; like a worm, etc.). the following criteria support this interpretation: a) the axial stem is always in the centre of the whorls and the whorls are arranged symmetrically around it; b) the cements of the axial stem continue into the whorls and there is no recognizable boundary between them (pl. 6, figs. 3–6, 11–13); c) the laterals of the last whorl originated from the branching of the axial stem and the axial stem does not possess its own wall (pl. 6, figs. 2–3, 4–5, 10–13); d) the axial stem never steps out over the last whorl. the holotype (pl. 4, fig. 1) exhibits numerous bowlto v-shaped whorls in longitudinal section, showing only some of the characteristics of izmirella cretacea summarized from the paratypes. the holotype is composed of at least 20 whorls. the axial stem is cut through several whorls. a reconstruction of a half-whorl of izmirella cretacea nov. gen., nov. sp. is given in fig. 6. rejuvenation of the thalli usually takes place at the boundary between two laminae (pl. 2, figs. 1–2; pl. 3, figs. 2, 4, pl. 4, fig.4). this boundary is marked by a dark horizon where individual whorls, at the base of the thalli, are usually developed as a soup-plate pile arranged densely one above the other. 3. discussion izmirella cretacea nov. gen., nov. sp. is a representative of fossil plants, most probably algae. however, because of the totally different characteristics, its systematic classifi cation within the known groups of algae is uncertain. in longitudinal sections, (parallel sections to the growth direction), through the thalli of izmirella-buildups, the individual laterals appears as cell rows, resembling some red algae (rhodophycea) with “large cells”, e. g. representatives of the genus lithoporella (foslie) or titanoderma nägeli (compare wray, 1977, fi g. 58; rasser, 1994; piller & rasser, 1999). izmirella may be ascribed to such algae if its thallus is fractured (pl. 5, fig. 6). in thin-sections of izmirella, the “large-cell”-like structures (similar to lithoporella), are in reality the radially arranged (similar to representatives of modern acetabulariaceae) “laterals” cut in cross section. cells with different sizes and arrangement may occur in some red algae, e. g. in crustose coralline red algae phymatolithon calcareum and lithothamnium coralloides (adey & mckibbin, 1970) or in recent genus tenarea (wray, 1977, fi g. 54). laterals in izmirella are, however, segments that are arranged as in the cups of recent dasycladales acetabularia – radially around the axial stem, which is not known from red algae. the radially arranged “laterals” and the axial stem connecting the successive whorls is a common feature of the dasycladales, family acetabulariaceae (see berger & kaever, 1992). in this group, individuals are usually isolated; the gregarious potential and the ability to build small bioherms, as in izmirella are very rare in the fossil record. neofigure 6: reconstruction of a half whorl of izmirella cretacea nov. gen., nov. sp. showing the radially arranged “laterals” that are subdivided internally and peripherally to laterals of the second and higher orders (compare also fig. 7). from the pores of the upper surface (shown in third lateral from left) open into the cross-sections of “tubes of the second layer” which are oriented perpendicular to the laterals of fi rst and higher orders. schematic, not to scale. figure 7: the branching pattern of the laterals of the fi rst, second and further orders (6 orders, see numbers) of the whorls. the branching doesn’t occur at exactly the same level. the wall between the tubes is zig-zag-like (wavy). schematic, not to scale. geologia croaticababa senowbari-daryan and ismail isintek: izmirella cretacea nov. gen., nov. sp., a complex alga from the lower cretaceous... 293 teutloporella bassoulett et. al. is the only representative (bassoulett et. al., 1978) of gregarious (numerous thalli growing one beside the other) dasycladales occuring in the oxfordian–tithonian according to granier & deloffre (1993) or oxfordian–berriasian according to schlagintweit & ebli (1999). for instance in the upper jurassic reef facies of sicily, this alga is very abundant in nodular microbioherms up to 30 cm in diameter (senowbari-daryan et al., 1994). the following features might support the affi liation of izmirella to the dasycladales: a) each thallus possesses an axial stem which passes through the individual whorls (pl. 4, figs. 1–2, 5; pl. 5, fig. 3; pl. 6, figs. 1–6, 13). the axial stem with a diameter of 40–80 µm, however, is extremely narrow to bear the weight of laterals with a diameter of about 3 mm, but the recent acetabularia also possesses a narrow stalk. it may be assumed that the arrangement of the thalli in rows and their growth strategy in izmirella, i. e. one beside the other, could help to support the individual thalli in growth position. b) the arrangement of the “laterals” is comparable with the rays (laterals) from caps of recent acetabularia, polyphysa or chalmasia, radiating around the axial stem (see berger & kaever 1992, fi gs. 3.56, 3.81, 3.91), c) the segments, i.e. whorls, are arranged vertically around the axial stem, one above the other. d) the microbioherms are composed of individual stacked thalli of izmirella. notwithstanding these apparent similarities, the verticillate organisation of the whorls around the axial stem and the septate nature of the laterals, do not conform to the features of the dasycladales (berger & kaever, 1992). the following features of izmirella argue against its assignment to dasycladales: a) calcite mineralogy of skeleton: the primary skeletal mineralogy of the dasycladales is aragonite; primary calcite in dasycladales is extremely rare. minor amounts of calcite do occur in some dasycladales e. g. in bornetella (flajs, 1977), and the membranes around the laterals of clypeina jurassica (favre) are composed of mg-calite (conrad & varol, 1990). similarly, the sporangia within the axial stem in diplopora iranica (senowbari-daryan & hamedani, 2000) were primary mg-calcite, but a primary mg-calcite mineralogy for the thallus of dasycladales is not known. the systematic position of some dasyclad type organisms, e. g. palaeozoic psedo vermiporella elliot, as dasycladales is uncertain (flügel, 2004). therefore, the primary calcite mineralogy of izmirella does not support its classifi cation as a dasycladalean. b) the branching pattern of the “tubes of the second layer” is similar to porostromate cyanophyceans like cayeuxia, hedstroemia or halysis mentioned above. however, such structures, originating from the radially arranged laterals around the axial stem, are not known from the dasycladales. ramifi cation of laterals to a higher order and the formation of the “chaotic tube” in izmirella are not characteristic for acetabulariaceae. gametangia, occurring in the laterals of e. g. acetabularia, have not been observed in the laterals of izmirella. c) also the “chaotic” (girvanella-like) tube layer between the individual thalli of izmirella rows does not support its interpretation as a dasycladacean. an alternative classifi cation to the dasycladales might be the red algae. actually a placement of izmirella in the peyssonneliacea could be envisaged. in this view the “stacked superimposed whorls” might be interpreted as lamellar thalli growing on some non-calcifi ed erect fi laments (= “axial stem”); figure 8: redrawn from pl. 3, fig. 7 (quadrangle) showing the edge of a trumpet-like broadened lateral, from which the tubes of the second layer originate. figure 9: section through the last cup of specimen illustrated in pl. 6, fig. 8 showing the large “cells” of the laterals, numerous tubes of the lid (appearing as bridge between the edges of the cup), micritic fi lling within the bowl (dotted area) and the small spherical elements (gametangia?) within the micritic fi lling. the white area within the micritic fi lling is sparry calcite cement. geologia croatica geologia croatica 61/2–3 294 this peculiar mode of life may be refl ected by the wavy “bowlshaped” aspect. nevertheless, this hypothesis looks inadequate if one considers the absence of a well-defi ned cellular network with a hypothallus and perithallus (denizot, 1968) which typifi es the peyssonneliacea. the cell-like structure (oval or rectangular) of the laterals in sections directly around the axial stem (pl. 4, figs. 3, 6; pl. 5, figs. 1–4; pl. 7, figs. 2, 5, 8), also are similar to some red algae (e. g. lithoporella, see wray, 1977, fi g. 56), but they are tube-like in izmirella. different cell sizes, developed as two tube layers of izmirella, is known from other red algae, e. g. in the crustose coralline red algae phymatolithon calcareum and lithothamnium coralloides (adey & mc kibbin, 1970). the cells are signifi cantly elongated during winter growth. also the mineralogy of the cells (i. e. content of mg) in modern calcareous red algae varies from summer to winter (milliman et al., 1971; kolesar, 1978). seasonal cell sizes and variation in mg-content in calcite of the cell walls is also known from fossil solenoporacean algae (wright, 1985; wendt, 1993). the different cell sizes, and possibly different content of mg in the cell wall of laterals and “tubes of the second layer” in izmirella could also refl ect seasonal variation, but these features do not justify classifying izmirella as a solenoporacean red algae. the fan-like branching pattern of the fi rst order of tubes and of the “chaotic” tube layer of izmirella could support its attribution to the cyanophyceans. such branching patterns of cells is common in cyanophyceans, but the axial stem of izmirella and the arrangement of laterals around the axial stem are features contrary to the affi liation of izmirella with this group. izmirella nov. gen. is surely an alga but its taxonomic position within the algae remain uncertain. acknowledgement the investigations were carried out within the research project “se 416/13” of the fi rst author supported by the deutsche forschungsgemeinschaft (dfg). we thank e. isikli (izmir) for her kind help during fi eld work and sample preparation. for critical reading of the fi rst draft of the manuscript and for helpful comments, we thank e. akay (izmir), i.i. bucur (cluj-napoca). p. genot (nantes) and p. de castro (naples). we thank also b. granier (brest) and an anonymous reviewer, whose helpful comments improved the manuscript. we are grateful to a. fagerstrom (boulder, usa) for his linguistic help and useful comments. references adey, w. & mckibbin, d.l. (1970): studies of the maerl species phyma tolithon calcareum (pallas) nov. comb. and lithothamnium corallio ides croun, in the ria de vigo. – botanica marina, 13, 100–106. akdeniz, n., konak, n., öztürk, z. & cakir, m.h. (1986): izmir-manisa dolaylarinin jeolojisi. – unpublished mta jeoloji etüd leri dairesi raporu, 164 p., ankara. bassoullet, j.p., bernier, p., conrad, m.a., deloffre, r. & jaffrezo, m. (1978): les algues dasycladales du jurassique et du crétacé. – geobios, mem. spéc. 2, 1–330. berger, s. & kaever, m.j. (1992): dasycladales. an illustrated mono graph of a fascinating algal order. – georg thieme verlag, stuttgart, new york, 247 p. conrad, m.a. & varol, b. (1990): cylindroporella taurica n. sp. urges to review different pattern of calcifi cation in the mesozoic dasycladales (green algae). – archs. sci. genève, 43/1, 193–214. de castro, p. (1993): observation on campbelliella radoičić, 1959 and neoteutloporella bassoullet et al., 1978 (green algae, dasycladales). – in: barattolo, f., de castro, p. & parente, m. (eds.): studies on fossil benthic algae. boll. soc. paleont. ital., spec. vol. 1, 121–184. denizot, m. (1968): les algues fl oridées encroutantes (à l´exception des corallinacéen). – lab. crypt. mus. hist. nat. paris, 1–310. erdoğan, b. (1990): izmir-ankara zonu´nun, izmir ile seferihisar arasindaki bölgede stratigrafi k özellikleri ve tektonik evrimi. – tpjd bülteni, 2/1, 1–20, ankara. flajs, g. (1977): ultrastrukturen des kalkalgenskelettes. – palaeontographica, abt. b, 160, 69–128. flügel, e. (2004): microfacies of carbonate rocks. analysis, interpretation and application. – springer, berlin, 976 p. granier, b. (2002): algues dasycladales, nouvelles ou peu connues, du jurassique supérieur et du crétacé inférieur du moyen-orient [new or little known dasyclad algae from upper jurassic and lower cretaceous series of the middle east – in french]. – in: bucur, i.i. & filipescu, s. (eds.): research advances in calcareous algae and microbial carbonates. presa universitara clujeana, cluj-napoca, 103–113. granier, b. & deloffre, r. (1993): inventaire critique des algues dasycladales fossiles. ii partie. les algues dasycladales du jurassique et du crétacé. – rev. palébiol., 12/1, 19–65. figure 10: section through two cups exhibiting the laterals (1) and the tubes of second layers (appearing dark between the laterals). the inside of the cup is covered with a thin micritic layer (dotted area). the white area in the centre of the cup is sparry calcite cement. between the edges of the cup the bridge-like appearing tubes (lid) are developed, from which the “new” and multibranched laterals originated (rejuvenation). redrawn from specimen illustrated in pl. 3, fig. 4. geologia croaticababa senowbari-daryan and ismail isintek: izmirella cretacea nov. gen., nov. sp., a complex alga from the lower cretaceous... 295 isintek, i., masse, j.p., altiner, d. & isin, b. (2000): age of a bauxite-bearing limestone block in the bornova wildfl ysch zone of the taurids. – intern. earth sci. colloq. on aegean regions, izmir. abstracts, p. 67. kolesar, p.t. (1978): magnesium in calcite from a coralline alga. – j. sed. petrol., 48, 815–820. luperto sinni, e. & masse, j.p. (1993): the early cretaceous da syc ladales from the apulia region (southern italy): biostratigraphic distribution and palaeobiogeographic signifi cance. – in: barattolo, f., de castro, p. & parente, m. (eds.): studies on fossil benthic algae. boll. soc. paleont. ital., spec. vol. 1, 295–309. milliman, j.d., gastner, m. & müller, j. (1971): utilization of magnesium in coralline algae. – geol. soc. amer., bulletin, 82, 573–580. munnecke, a., servais, t.h., & vachard, d. (2001): halysis hoeg, 1932 – a problematic cyanophyceae: new evidence from the silurian of gotland (sweden). – n. jb. geol. paläont. mh., 2001/1, 21–42. peybernes, b. & conrad, m.a. (1979): les algues du crétacé inferieur de hongrie. – bull. cent. rech. explor. – prod. elf-aquitaine, 3/2, 743–752. piller, w.e. & rasser, m. (1999): applicaton of neontological taxonomic concepts to late eocene coralline algae (rhodophyta) of the austrian molasse zone. – j. micropaleont., 18, 67–80. rasser, m. (1994): facies and palaeoecology of rhodoliths and acervulinid macroids in the eocene of the krappfeld (austria). – beitr. paläont., 19, 191–217. riding, r. & voronova, l. (1985): morphological groups and series in cambrian calcareous algae. – in: toomey, d.f. & nitecki, m.h. (eds.): paleoalgology. springer, 56–78. schindler, u. & conrad, m.a. (1994): the lower cretaceous dasycladales from the northwestern friuli platform and their distribution in chronostratigraphic and cyclostratigraphic units. – rev. paleobiol., 13/1, 59–96. schlagintweit, f. & ebli, o. (1999): new results on microfacies, biostratigraphy and sedimentology of late jurassic. early cretaceous platform carbonates of the northern calcareous alps. – abh. geol. b.a., 56/2, 379–418. senowbari-daryan, b., bucur, i.i. & abate, b. (1994): upper jurassic calcareous algae from the madonie mountains, sicily. – beitr. paläont., 19, 227–259. senowbari-daryan, b. & hamedani, a. (2000): obertriadische (nor) dasycladaceen aus der nayband-formation vom zentraliran. – rev. paléobiol., 19/1, 97–121. velić, i. & sokač, b. (1983): stratigraphy of the lower cretaceous index fossils in the karst dinarides ‘(yugoslavia). – zitteliana, 10, 485–491. wray, j.l. (1977): calcareous algae. – elsevier, amsterdam, 185 p. wendt, j. (1993): solenoporacean stromatolites. – palaios, 8, 101–110. wright, v.p. (1985): seasonal banding in the alga solenopora jurassica from the middle jurassic of gloucestershire, england. – j. paleont., 59/3, 721–732. manuscript received november 9, 2007 revised manuscript accepted may 19, 2008 geo.cro.2-3-61-kb.pdf 311 � bruno granier1, dimas dias-brito2 and ioan i. bucur3 ab stra ct calcareous albian-cenomanian strata in the potiguar basin yield a number of microfossils, among which are calcareous algae (dasycladales and corallinales). this data, together with an inventory of previous discoveries, enabled the discussion of their biogeography. these benthic organisms probably came from the early central atlantic ocean through its northwestern neck between africa and south america and thus reached the early south atlantic platforms. keywor ds: calcareous algae, albian, cenomanian, potiguar basin, brasil, biogeography 1 département des sciences de la terre, ufr des sciences et techniques, université de bretagne occidentale (ubo), 6, avenue le gorgeu, f-29238 brest cedex 3 france; (bgranier@univ-brest.fr) 2 unesp – universidade estadual paulista – rio claro, igce, departamento de geologia aplicada, caixa-postal 178, av. 24 a 1515, bela vista, 13506-900 – rio claro, sp brazil 3 department of geology, babes-bolyai university, str. m. kogalniceanu nr.1, 400084 cluj-napoca romania; (ibucur@bioge.ubbcluj.ro) calcareous algae from upper albian – cenomanian strata of the potiguar basin (ne brazil) geologia croatica 61/2–3 311–320 2 figs. 1 tab. 2 pls. zagreb 2008 geologia croaticageologia croatica � 1. introduction calcareous algal remains are common components of midcretaceous shallow-water carbonate rocks in brazilian sedimentary basins. however, here, as in the other basins of the southern hemisphere, they are poorly documented. this study focuses on the fossil algae found in an offshore well of the potiguar basin, north of macau (fig. 1). the cursory inventory of the fossil algal assemblage in this area is supplemented by a discussion of earlier published records regarding the early south atlantic ocean. 2. geologic and stratigraphic settings cretaceous outcrops of shallow-water marine carbonates are known only from northeastern brazil, (e.g., the sergipe, pernambuco-paraiba, araripe, and potiguar basins). in the subsurface, these carbonate successions, attaining hundreds of metres in thickness, were identifi ed from seismic and welllogging data. this is also the case offshore on the continental margin between latitudes 28° and 2° s, where they are of albian age in southern, southeastern and eastern tracts (i.e., the santos, campos, espírito santo, and jequitinhonha basins), and of albian to campanian age in northeastern and equatorial areas (e.g., the basins listed above plus the barreirinhas basin). the studied material comes from a petrobrás exploration well (fig. 1) drilled through the albian-cenomanian carbonate sequence of the ponta do mel formation (tibana & terra, 1981). according to dias-brito (1985), the upper part of the lower ponta do mel formation, of early to middle albian age, represents low-energy “deep-water” mud-dominated fabrics: mudstone and wackestone facies with planktonic foraminifera (hedbergellids and favusella washitensis) and pithonellids. the upper ponta do mel, late albian to cenomanian in age, displays mainly high-energy “shallow-water” grain-dominated fabrics: ooid-oncoidal grainstone and packstone facies commonly with red algae (and a few benthic foraminifera: andersenolina sp. and lituolids), and locally with algal (rhodalgal) biolithites (tibana & terra, 1981; terra, 1990; terra & lemos, 1999). the boundary between these sub-units of the geologia croatica geologia croatica 61/2–3 312 ponta do mel formation appears to record a rapid lowering of sea level, that is a forced regression; it is therefore interpreted as being a major sequence boundary. the studied material consists of 31 thin sections that were cut from cores taken in the uppermost part of the ponta do mel formation (fig. 1); consequently it is possible that the fossils described are all of cenomanian age. 3. preliminary inventory of the brazilian mid-cretaceous algae division chlorophyta class chlorophyceae kützing, 1843 order dasycladales pascher, 1931 family triploporellaceae (pia, 1920) tribe triploporelleae (pia, 1920) sub-tribe linoporellinae pia, 1927 genus linoporella steinmann, 1899 linoporella sp. (pl. 1, figs. b & e) the type species l. capriotica (oppenheim, 1899) was recently revised by barattolo & romano (2005). our specimens present affi nities with the named species: a rather short and thin primary, rather long and thin secondary’s, and tertiaries that are rather short and thin. this material is very fragmentary and does not allow more precise identifi cation. tribe salpingoporelleae bassoullet et al., 1979 sub-tribe salpingoporellinae bassoullet et al., 1979 genus holosporella pia, 1930 holosporella nkossaensis p. masse, 1995 (pl. 2, fig. f) as in the type-specimens of this poorly known form, calcifi cation in our material is rather weak and the structures are in part masked by micritization. family dasycladaceae kützing, 1843 tribe dasycladeae pia, 1920 sub-tribe cymopoliinae genus cymopolia j.v. lamouroux, 1816 cymopolia perkinsi johnson, 1968 (pl. 1, fig. c) first described from texas, this species was probably illustrated from the congo as “dasycladacea ind.” in p. masse (1995; pers. comm., 2008). it has strong calcifi cation along the main axis and on the outer end of the laterals (around the fertile ampulla and the surrounding sterile secondaries). fi gu re 1: location of the studied exploration well rns-11 off shore macau. the observed ranges of the fossils (cored interval only) are plotted next to the gamma-ray well log, since detail data on lithology are not available. material from i̇andaira fm. is not studied here. scale: each interval = 100 m. geologia croaticabruno granier et al.: calcareous algae from upper albian – cenomanian strata of the potiguar basin (ne brazil) 313 remarks: specimens illustrated by terra (1990: fotos 18–19) and ascribed to actinoporella should not be referred to that genus but are representatives of cymopolia. sub-tribe neomeriineae genus neomeris j.v. lamouroux, 1816 neomeris is very common in our material and presents two patterns for the position of the fertile ampulla: it is either set between two sterile secondaries, as in the sub-genus neomeris, or both sterile secondaries are below the associated ampulla, as in the sub-genus larvaria. their identifi cation at the species level is barely feasible in thin section, (the most complete delineations were obtained from washed samples of unconsolidated cenozoic sediments). neomeris (neomeris) sp. (pl. 1, fig. a; pl. 2, fig. i) neomeris cretacea which was revised by barattolo (1990) is in this fi rst group. it was not discovered in the potiguar basin, but it is known from the neighbouring sergipe basin (granier et al., 1991a, 1991b). neomeris (larvaria) sp. (pl. 2, fig. h) some representatives of this sub-genus are found in the potiguar basin. family polyphysaceae kützing, 1843 indeterminate polyphysaceae (pl. 1, figs. d, f) the available material is poorly calcifi ed and suffered micritization which partly masks the structures. division rhodophyta class rhodophyceae rabenhorst, 1863 order corallinales silva & johansen, 1986 family sporolithaceae verheij genus sporolithon heydrich, 1897 sporolithon sp. (pl. 2, fig. c) occurrences and records of the genus are rare in the south american scientifi c literature. terra (1990) illustrated a form (op. cit.: “foto 9”) from the ponta do mel formation of the potiguar basin that he ascribed to the “coralináceas” and which we fi nd to be is a genuine sporolithon (the photomicrograph clearly documents the existence of sori). srivastava (1982a; fi gs. 23–24) illustrated archaeolithothamnium, a synonym for sporolithon; but his specimens are younger for they were discovered in the jandaíra formation. similarly a specimen illustrated by berthou & bengston (1983, pl. 3, fi g. 3–4) from the cotinguiba formation in the sergipe-alagoas basin is of coniacian age. the occurrence of sori in some poorly preserved specimens allows us to ascribe them to this genus. sporolithon amphiroaeformis (rothpletz,1891) (pl. 2, figs. d, g) the material includes a non-geniculate (= unarticulated) encrusting coralline. its thallus has fructicose branches, for most sections cut through fi nger-like protuberances. some sections display unisporangial conceptacles (sori), a reproductive feature known only from the family sporolithaceae. however, regarding the internal structure, the monomerous thallus displays core cells with a coaxial arrangement (i.e. core cells arranged in tiers). this growth pattern is rather rare in the genus sporolithon as most representatives have central cores of non-coaxial fi laments (woelkerling, 1988). there are few records of coaxial growth: for instance, townsend et al., (1995; woelkerling, pers. comm. 2008) reported that both coaxial and non-coaxial growths occur in sporolithon durum (foslie). to confi rm our identifi cation of the species, the material was compared with topotypic material, from “la cadière, dans le bassin du beausset”, var, france, available from the collections of mme p. lemoine (1917) and j. pfender (1926). family hapalidiaceae j.e. gray, 1864 subfamily melobesioideae bizzozero, 1885 genus lithothamnion heydrich, 1897 we did not fi nd representatives of this genus in the potiguar basin, but they are known from the neighbouring sergipe basin. most specimens ascribed to lithothamnium angolense romanes, 1916, in the study of the sergipe basin by granier et al. (1991b), represent an undetermined species of litho thamnion but cannot be ascribed expressly to l. angolense (which is a synonym for marinella lugeoni pfender, 1926). some illustrated sections (op. cit.: pl. 2, fi gs. 1, 3, 5–6; pl. 3, fi g.1) exhibit the multiporate conceptacles that are known to host asexual reproductive organs, a characteristic feature of the family hapalidiaceae. family solenoporaceae pia, 1927 the current taxonomic knowledge of the other fossil rhodophytes requires a major revision which is beyond the scope of the present study. the re-study of the type-material of species ascribed to the genera solenopora, parasolenopora, pseudosolenopora, parachaetetes, will probably reveal a number of erroneous generic ascriptions as well as a number of synonyms. however, there are three discrete species that were easy to identify. genus elianella pfender & basse, 1947 elianella elegans pfender & basse, 1947 (pl. 2, fig. e) elianella consists of more or less stacked fi les of cells, transverse sections of which are polygonal or circular depending on the degree of amalgamation. within a fi lament, individual cells are barrel-shaped and the wall between two successive cells looks like a watch glass, i.e. it is curved outward (in the direction of growth). cells of discrete fi laments may be arranged in regular rows. genus pycnoporidium yabe & toyama, 1928 pycnoporidium sinuosum johnson & konishi, 1960 (pl. 2, fig. b) pycnoporidium is characterized by stacked sinuous (vide specifi c name) fi les of cells. it is a major contributor to limestone sedimentation. geologia croatica geologia croatica 61/2–3 314 plate 1 a neomeris (neomeris) sp.: oblique section. b, e linoporella sp.: oblique section. c cymopolia perkinsi: oblique section. d–f polyphysaceae ind., d: subaxial section, f: subtransverse section. figures a & c are at the same scale –500 µm; figures b & d–f are at another scale –500 µm. geologia croaticabruno granier et al.: calcareous algae from upper albian – cenomanian strata of the potiguar basin (ne brazil) 315 geologia croatica geologia croatica 61/2–3 316 plate 2 a marinella lugeoni (“bouff ées de pipe”). b pycnoporidium sinuosum. c sporolithon sp. (with typical sori). d sporolithon amphiroaeformis (left) and andersenolina sp. (right). e elianella elegans; f) holosporella nkossaensis: oblique section. g sporolithon amphiroaeformis (with typical sori). h neomeris (larvaria) sp.: tangential section. i another neomeris (neomeris) sp.: oblique section. all fi gures, except g – 100 µm, are at the same scale –500 µm. geologia croaticabruno granier et al.: calcareous algae from upper albian – cenomanian strata of the potiguar basin (ne brazil) 317 geologia croatica geologia croatica 61/2–3 318 genus marinella pfender, 1939 marinella lugeoni pfender, 1939 (pl. 2, fig. a) the fi laments are narrower and they display constrictions at regular intervals (without true walls as illustrated by baratollo & del re, 1985). the typical shape of the thallus is that of a puff of pipe smoke (“bouffée de pipe”). 4. discussion of the biogeographic results though the assemblage contains representatives of many algal families (triploporellaceae, dasycladaceae, polyphysaceae, sporolithaceae, hapalidiaceae, and solenoporaceae), its diversity is very low, each family being represented by one or rarely two genera or species. but we remain very cautious about coming to any defi nite conclusion on the diversity issue for some well-known species, such as polystrata alba (pfender, 1926), a gigartinale which occurs in both congo and nigeria, were not identifi ed in the potiguar basin. their absence may only be because of the sparseness of adequate sampling. in addition, in south america, with the exception of the potiguar basin, there are very few data available on palaeophycological occurrences. also, some records are erroneous: for instance, the dasycladales illustrated by leguizamon et al. (1993) are bryozoans. however a synthesis of earlier discoveries and the results of this preliminary inventory, provides some keys to an understanding of the observed patterns. for instance, earlier occurrences from other localities in both central and south america (guatemala: johnson & konishi, 1960; johnson & kaska, 1965; venezuela: johnson, 1965; brazil: srivastava, 1982a, 1982b, 1984; berthou & bengston, 1988; granier et al., 1991a, 1991b), as well as from the opposite side of the south atlantic ocean (nigeria: poignant & lobitzer, 1982; gabon: rousselot, 1995; congo: p. masse, 1995; angola: romanes, 1916), suggest that during mid-cretaceous times the diversity of these algal associations was low on both sides of the south atlantic ocean. the new discoveries do not contradict this hypothesis, in contrast they appear to add to its strength. fi gu re 2: palaeogeographic reconstruction used to locate fossil localities for the albian-cenomanian interval (map at – 100 ma based on scotese’s paleomap project, http://www.scotese.com/). 1: arizona and texas, johnson, 1954, 1965, 1968; konishi & epis, 1962; 2: mexico, barattolo, 1983, 1990; 3: guatemala, johnson & konishi, 1960; johnson & kaska, 1965; 4: venezuela, johnson, 1965; 5–6: brazil, 5: potiguar, srivastava, 1982a, 1982b, 1984, 6: sergipe, berthou & bengston, 1988; granier et al., 1991a, 1991b; 7: nigeria, poignant & lobitzer, 1982; 8: gabon, rousselot, 1995; 9: congo, masse, 1995; 10: angola, romanes, 1916. table 1: albian-turonian occurrences of calcareous algae recorded in western africa and central and south america, originally determined as: (a) neomeris budaense n.sp. (johnson, 1968); (b) heteroporella potiguarensis n.sp. (srivastava, 1982a); (c) dasycladacea ind. (p. masse, 1995); (d) permocalculus budaensis n.sp. (johnson, 1968); (e) trinocladus norteriograndensis n.sp. (srivastava, 1982b); (f) both marinella lugeoni and lithothamnium primitiva (johnson & kaska, 1965, usnm n° p 042547a); (g) lithophyllum? venezuelaensis (johnson, 1965, usnm n° p 042467); (h) lithothamnium regonis n.sp. (haug in maury, 1937); (i) lithothamnium angolense n.sp. (romanes, 1916); (j) parachaetetes keitheiti (poignant in granier et al., 1991b); (k) parachaetetes sp. (terra & lemos, 1999); no fi g. (poignant’s collection). 1 arizona and texas 2 mexico 3 guatemala 4 venezuela 5-6 brazil 7 nigeria 8 gabon 9 congo 10 angola 5-potiguar 6-sergipe heteroporella lepina (a) (b) holosporella nkossaensis cymopolia perkinsi (c) neomeris cretacea genotella pfenderae no fig. trinocladus sp. (d) (e) marinella lugeoni (f ) (g) (h) no fig. (i) pycnoporidium sinuosum (j) sporolithon amphiroaeformis lithothamnion sp. elianella elegans (k) ethelia alba no fig. geologia croaticabruno granier et al.: calcareous algae from upper albian – cenomanian strata of the potiguar basin (ne brazil) 319 furthermore,this preliminary inventory provides supplementary information and data concerning the origin of these algae (and the associated benthic foraminifers): 4.1. did the algae come from the south? the paleolatitudinal location of the southern ends of the african and south american continents near the south-polar realm (see the extension of the mid-cretaceous tethyan realm, i.e. the megatethys, on fig. 22 in dias-brito, 2000 or on fig. 2 in bellier & vrielynck, 2007) precludes a southern origin for these temperature-sensitive organisms. 4.2. did they come from the tethyan realm through the trans-saharan seaway? according to moullade & guérin (1982) who discuss the patterns of foraminiferal distribution, this hypothesis has not been thoroughly documented for the oldest part of the interval: “le passage ‘transsaharien’ n’a jamais été documenté sérieusement pour cette période”. for the youngest part of the interval we consider that the environments (siliciclastic-rich facies and associated water-turbidity) along this pathway were probably unfavourable to algal growth and their subsequent dissemination. 4.3. did they come from the tethyan realm through the north-western neck of the south atlantic ocean? it is possible that these benthic organisms reached the early south atlantic ocean through a channel formed by the set of rifts and transform faults that existed between the shoulders of both continents and connected it to the early central atlantic ocean. there are some similarities between the south atlantic algal assemblages and those in texas, mexico, guatemala and venezuela (though here again the albian-cenomanian series are poorly documented). these similarities support this interpretation. however, we should consider that colonization of the south atlantic shorelines by dasycladales and corallinales did not occur in the same way. rhodophytes are common in most shallow-water marine palaeoenvironments where they occasionally build up small knolls (“reefs”), but they are not confi ned to the sublittoral zone for they are also found in slight ly cooler or deeper marine palaeoenvironments. consequently the relative abundance of these wide-spread opportunist forms on the early south atlantic ramps is not surprising. it is a different story for the chlorophytes. modern dasycladales are either choristosporate or umbrellosporate and their albian-cenomanian relatives appear to have pioneered in the early south atlantic ocean: dasycladaceae (choristosporate forms), such as neomeris (n.), neomeris (l.), genotella and cymopolia, are common in the study area; polyphysaceae (umbrellosporate forms) are also abundant. as this was a time of change in the evolution of the dasycladales, (near the end of the range of the family triploporellaceae), it is probable that this distribution is related to the peculiar pattern of their reproductive organs that gave them an “evolutionary advantage” rather than to a control only by the then-existing latitudes. though calcareous algae provide a unique tool to investigate the palaeobiogeography of the early south atlantic ocean, one should not overlook other (non-algal) groups or the overall fossil assemblage. there is no doubt that planktonic organisms used a route from the central to the south atlantic, possibly as early as late aptian times (see dias-brito & ferré, 2001; bellier & vrielynck, 2007). some benthic foraminifera followed the same route, but at a later date (see moullade & guérin, 1982). we think that organisms that lived with photosynthetic symbionts: foraminifera like the orbitolinids (apparently absent on the south atlantic ramps) but also macrofossils like the rudists and corals, (for which the fossil record is scanty) are potentially excellent case studies. in any case, we are required to supplement our current database on both the south american and african continents, to add validity to our hypothesis. 5. conclusion this preliminary study adds to the palaeophycological inventory of the south atlantic basins. the list of taxa encountered is still short, thus suggesting that diversity was low. the benthic green and red calcareous algae probably originated in from the central atlantic ocean and reached the early south atlantic ocean through a north-western passageway between western african and south america. their paucity is possibly related to the degree of capability of each algal group (at the family or even the genus levels) to colonize new coasts, an hypothesis that will require further investigation. aknowledgement the authors thank petrobrás for ceding the investigated material, previously to the creation of the brazilian petroleum national agency – anp. we thank bill woelkerling, filippo baratollo, and werner piller, who provided helpful comments that improved the manuscript, as well as nestor sander for corrections of the english text. references barattolo, f. (1983): observazioni su triploporella steinmannii n. sp. (alghe verdi, dasicladali) del cretacico del messico. – bollettino della società dei naturalisti in napoli, 91 (1982), 35 p. barattolo, f. (1990): remarks on neomeris cretacea steinmann (chlorophyta, dasycladales) from the cretaceous of orizaba (typelocality), mexico. – boll. soc. paleontol. ital., 29/2, 207–218. barattolo, f. & del re, m.r. (1985): alghe rosse solenoporacee del cenomaniano dei dintorni di caserta (appennino meridionale, italia). – bollettino della società dei naturalisti in napoli, 93 (1984), 1–53. barattolo, f. & romano, r. (2005): the genus linoporella steinmann, 1899 and its type-species linoporella capriotica (oppenheim, 1899) from the early cretaceous of capri. – boll. soc. paleontol. ital., 44/3, 237–254. bellier, j.-p. & vrielynck, b. (2007): distribution des foraminifères planctoniques au passage albien-cénomanien dans l’atlantique nord: indices de l’existence d’une zonation latitudinale dans la province téthysienne. – rev. paléobiol., 26/1, 55–62. geologia croatica geologia croatica 61/2–3 320 berthou, p.-y. & bengston, p. (1983): microfossiles et échinodermes incertae sedis des dépôts albiens à coniaciens du bassin de sergipe-alagoas, brésil. – cahiers de micropaléontologie, 3 (1982), 13–23. berthou, p.-y. & bengston, p. (1988): stratigraphic correlation by microfacies of the cenomanian-coniacian of the sergipe basin, brazil. – fossils and strata, 21, 88 p. dias-brito, d. (1985): calcisphaerulidae do albiano da bacia potiguar, rio grande do norte – brasil: consideraçőes paleoecológicas e biocronoestratigráfi cas. – mme/dnpm, coletânea de trabalhos paleontológicos, (geologia), seçăo paleontologia e estratigrafi a, 27/2, 307–314. dias-brito, d. (2000): global stratigraphy, palaeobiogeography and palaeoecology of albian –maastrichtian pithonellid calcispheres: impact on tethys confi guration. – cretaceous res., 21, 315–349. dias-brito d. & ferré, b. (2001): rovearinids (stemless crinoids) in the albian carbonates of the offshore santos basin, southeastern brazil: stratigraphic, palaeobiogeographic and palaeoceanographic signifi cance. – j. s. am. earth sci., 14/2, 203–218. granier, b., berthou, p.-y. & fourcade, e. (1991a): the dasycladalean algae from the cretaceous of the new world. – transactions of the second geological conference of the geological society of trinidad and tobago, port-of-spain (april 2nd–8th, 1990), 178–183. granier, b., berthou, p.-y. & poignant, a.f. (1991b): constructions bio-sédimentaires laminées, lithothamnium et parachaetetes de la formation riachuelo (albien) du bassin de sergipe (nord -est du brésil). – geocięncias, 10, 169–181. johnson, j.h. (1954): an introduction to the study of rock building algae and algal limestones. – quarterly of the colorado school of mines, 49/2, 117 p. johnson, j.h. (1965): three lower cretaceous algae new to the americas. – j. paleontol., 39/4, 719–730. johnson, j.h. (1968): lower cretaceous algae from texas. – professional contributions of the colorado school of mines, 4, 71 p. johnson, j.h. & konishi, k.j. (1960): an interesting late cretaceous calcareous algae from guatemala. – j. paleontol., 34/6, 1099–1105. johnson, j.h. & kaska, h.v. (1965): fossil algae from guatemala. – professional contributions of the colorado school of mines, 1, 152 p. konishi, k.j. & epis, r.c. (1962): some early cretaceous calcareous algae from cochise county, arizona. – micropaleontology, 8/1,67– 76. leguizamon, r., asato, c.g. & camacho, h.h. (1993): algas calcareas de la formacion arroyo verde (eoceno, provincia del chubut, argentina). – ameghiniana, 30/1, 9–15. lemoine, mme p. (1917): contributions à l’étude des corallinacées fossiles. iv. sur la présence du lithophyllum amphiroaeformis rothpl. dans l’albien de vinport (landes). – bull. soc. géol. france, (4e série), 17/3–5, 6, 280–283. masse, p. (1995): calcareous algae and microcoprolites of the albian platform carbonates of the congo margin. – bull. centr. rech. explor. – prod. elf aquitaine, 19/2, 301–317. maury, c.a. (1937): o cretaceo de sergipe. – serviço geológico e mineralógico do brasil, monographia, 11, 263 p. moullade, m. & guérin, s. (1982): le problème des relations de l’atlantique sud et de l’atlantique central au crétacé moyen: nouvelles données microfauniques d’après les forages d.s.d.p. – bull. soc. géol. france, 7, 24/3, 511–517. oppenheim, p. (1889): beiträge zur geologie der insel capri und der halbinsel sorrent. – z. deutsch. geol. ges., 41, 442–458. pfender, j. (1926): les mélobésiées dans les calcaires crétacés de la basse-provence. – mém. soc. géol. france (n.s.), 3/2, 6, 32 p. poignant, a.f. & lobitzer, r. (1982): les algues de l‘albien supérieur du nigéria. – cahiers de micropaléontologie, 2, 35–40. romanes, m.e. (1916): note on an algal limestone from angola. – transactions of the royal society of edinburgh, 51/3, 581–584. rousselot, s. (1995): dynamique sédimentaire du bassin intérieur gabonais au crétacé (albien et turonien). – thèse nouveau doctorat, école nationale supérieure des mines de paris, n° 95 ensmp 0591, 318 p. srivastava, n.k. (1982a): calcareous algae from jandaíra formation (potiguar basin), brazil: part i. – anais da academia brasileira de cięncias, 54/1, 219–231. srivastava, n.k. (1982b): trinocladus norteriograndensis, n.sp., a new dasycladacean alga from jandaíra formation (potiguar basin), northeastern brasil: part ii. – boletim do departamento de geologia (cce/ufrn), 6, 23–26. srivastava, n.k. (1984): algas calcareas e seus ambientes deposicionais na formaçâo jandaíra da bacia potiguar (rn), parte iii. – atas do xi simposio do nordeste, 361–369. terra, g.j.s. (1990): fácies, modelo deposicional e diagęnese da seqüęncia carbonática albo-cenomaniana (formaçăo ponta do mel) da bacia potiguar. – dissertaçăo de mestrado, instituto de geocięncias, universidade federal do rio de janeiro, 153 p. terra, g.j.s. & lemos, v.b. (1999): algas solenoporáceas do albo-cenomaniano das bacias do nordeste do brasil – implicaçőes paleoecológicas e paleobiogeográfi cas. – 5° simpósio sobre o cretáceo do brasil – 1° simpósio sobre el cretácico de américa del sur, serra negra, sp, 23–28. tibana, p. & terra, g.j.s. (1981): seqüęncias carbonáticas do cretáceo na bacia potiguar. – boletim técnico da petrobrás, 24/3, 174– 183. townsend, r.a., woelkerling, w.j., harvey, a.s. & borowitzka, m. (1995): an account of the red algal genus sporolithon (sporolithaceae, corallinales) in southern australia. – aust. syt. bot., 8, 85–121. woelkerling, w.j. (1988): the coralline red algae. – british museum (natural history), oxford university press, 268 p. manuscript received december 20, 2008 revised manuscript accepted june 16, 2008 saftic.indd tertiary subsurface facies, source rocks and hydrocarbon reservoirs in the sw part of the pannonian basin (northern croatia and south-western hungary) bruno saftić1, josipa velić1, orsolya sztanó2, györgyi juhász3 and željko ivković4 1. introduction hydrocarbon exploration resulted in an enormous amount of data about the structure, sedimentary fill and evolution of the pannonian basin (horváth & royden, 1981; royden & horváth, 1988; bérczi et al., 1988; szentgyörgyi & juhász, 1988; juhász, 1991, 1994; horváth & tari, 1999; prelogović et al., 1998; lučić et al., 2001; velić et al., 2002). some of the most important results from the croatian part of the study area regretfully remained unpublished (šimon, 1980); they have been used here together with other data from the archives of ina, zagreb (croatian national oil company). above the historically complex basement the structure of the study area is complicated (csontos et al., 1992; csontos 1995; csontos & nagymarosy, 1998): elongated basement highs and narrow depressions developed during mid-miocene rifting (horváth & royden, 1981; horváth, 1993), refigured by several phases of basin inversion prior to, during and after the subsequent thermal subsidence (horváth, 1995; horváth & cloetingh, 1996; prelogović et al., 1998; tari & pamić, 1998; horváth & tari, 1999; fodor et al., 1999; pavelić, 2001; tomljenović & csontos, 2001; csontos et al., 2002). a neogene sedimentary succession up to 5–7 km in thickness was accumulated in these depressions which are separated by uplifted and partially eroded units. the aforementioned depressions (sub basins) – the most northern mura, the western and the eastern part of the drava, the sava and the slavonija–srijem depressions (fig. 1), are hosts of important source rocks and petroleum reservoir rocks. some of the basement highs are exposed as palaeozoic–mesozoic mountains (e.g. mecsek, villány, papuk, psunj, etc.), others are still covered by about a 1–2 km thick pile of neogene sediments. conditions for the accumulation and preservation of large quantities of marine and terrigeneous organic matter were most favourable during the badenian, sarmatian and early pannonian in deep basin settings (horváth et al., 1988; dank, 1988; alajbeg et al., 1990; barić et al., 1989, 1992; hernitz et al., 1995a, b). the generation of hydrocarbons was geologia croatica 56/1 101–122 13 figs. zagreb 2003 key words: paratethys, lake pannon, miocene, pliocene, quaternary, subsurface facies, source rocks, hydrocarbon reservoirs, sedimentation, tectonics, pannonian basin, croatia, hungary. 1 faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, 10000 zagreb, croatia; e-mail: bsaft@rgn.hr 2 department of geology, eötvös university, pázmány péter st. 1/c, 1117 budapest, hungary; e-mail: sztano@ludens.elte.hu 3 hungarian geological institute, stefánia út 14, 1143 budapest, hungary; e-mail: juhaszgy@mafi.hu 4 ina industrija nafte dd., naftaplin, šubićeva 29, 10000 zagreb, croatia; e-mail: zeljko.ivkovic@ina.hr abstract the neogene sedimentary successions of the drava, sava and slavonija–srijem depressions in the sw part of the pannonian basin system are built up of three 2nd order megacycles separated by four major erosional unconformities. the first megacycle contains terrestrial to marine syn-rift and early post-rift sediments of early to mid-miocene age. the second is built up of late miocene lake pannon deposits, while the third contains those sediments which were deposited in the remnants of lake pannon and in the subsequent fluvial systems, in areas of continuous subsidence associated with basin inversion from the pliocene onwards. most of the petroleum source rocks and reservoir rocks are of miocene age and were formed during the first and second depositional megacycle. conditions for the accumulation and preservation of large quantities of marine and terrigenous organic matter were most favourable during the badenian, sarmatian and early pannonian, in deep basin settings, partly associated with rifting. the generation of hydrocarbons was promoted by relatively high geothermal gradients during the initial and subsequent thermal subsidence. various sedimentary environments produced deposits with good reservoir characteristics: e.g. fault-related talus breccia (mainly lower miocene), reefs (mainly badenian), coastal, shallow marine (karpatian, badenian) and deltaic (pannonian–pontian) sand bodies or turbiditic sand lobes (mainly pannonian). the hydrocarbon (hc) migration paths were often provided by the major unconformities bounding the three megacycles, as well as by faults, particularly around the basement highs. 102 geologia croatica 56/1 pannonian basin is a historically complex basin developed parallel with the alpine–carpathian orogen. its northern part, the alcapa unit, escaped from the alpine zone and was juxtaposed to the southern tisza unit along the mid-hungarian line during the late eocene– early miocene (csontos & nagymarosy, 1998, and references therein). thereafter the neogene pannonian basin proper, opened as a back arc basin in which extension was manifested through a set of low angle normal (tari et al., 1999) and strike-slip faults. extension was coeval with the compression within the carpathian thrust belt (horváth & royden, 1981). paratethys was an enclosed sea existing from oligocene to middle miocene times consisting of a chain of basins of various tectonic origin (báldi, 1980). these basins were covered most of the time by the same mass of water, sharing a similar aquatic biota, communicating between the mediterranean and the indopacific realm. when paratethys became separated from other seas in the beginning of the late miocene, the lake pannon individualized with decreasing salinity (cf. magyar & geary, 1999; müller et al., 1999). as both paratethys and lake pannon were characterized by an increasing rate of endemism, a local chronostratigraphic scheme was developed as used in figs. 2–4 (for detailed discussion the reader is referred to vass et al., 1987; rögl & daxner-höck, 1996; vass, 1999; magyar et al., 1999a, b). promoted by relatively high geothermal gradients (between 3–4 and 7ºc/100 m – horváth et al., 1988) during the subsequent thermal subsidence. various sedimentary environments produced deposits with good reservoir characteristics (fig. 2), e.g. fault-related talus breccia (mainly lower miocene), reefs (mainly badenian), coastal, shallow and open marine (karpatian, badenian, sarmatian) and deltaic (pannonian–pontian) sand bodies or turbiditic sand lobes (mainly pannonian). these are only the most frequent occurrences; almost all of the mentioned environments existed contemporaneously. the hc migration paths were often provided by the major unconformities as well as by faults, particularly around the basement highs. the late stage inversion of the basin promoted accumulation of the hydrocarbons in areas of active uplift (horváth, 1995). the aim of this paper is to review the sedimentary facies and depositional environments with special regard to the potential source and reservoir rocks in the se part of the pannonian basin. 2. geological setting the studied sediments from sw hungary and n croatia were deposited in the pannonian basin, the largest intramontaine basin of central paratethys (fig. 1). the fig. 1 location map. 103 s aftić, velić, s ztanó, juhász & ivković: tertiary s ubsurface facies, s ource r ocks... fig. 2 s chem atic section – lithostratigraphic units and the three n eogene depositional m egacycles. sava depression s n siroko polje fm. ndstar ivanic pm. ivanic grad fm. legend: ~ ~-... -_ --.i l ~ ~ osfm. ,, ~--~ vokanic~ ~ ~ ~ v v pyroclastic rocks ~ , i~~h~~ 1j a s e neog d sandstone arkoie ~ oo~ gravel .,oa[ d sandstone graywacke ii ... d ~-.d=l i::~=i clay effi3 calcareous ~ m.d neogene depositional megacycles s '.6 lulogo.ra, flil. c:: w post-rift 0 ? 0 subsidence ::; z kloiitarivanicfm. ~ a: z w 0 z a. z a. ivanie grad fm. 8: ::;) ~ ,~ ~ ibadenian karpatian -j ottna. ngw<1 i _ _ 18.3 eggi:.ni burgian egerian drava depression n verafm uj?alu'{ini.· • o.:ijc:k ...... u > o ~ jr' a~" f,lpl6 '£i1jl. ~. ,:;."~ " ~ > correlation horizons: ~ major and minor ~ unconformities ej sti"',.,r-"" conformable ""'",,, 104 geologia croatica 56/1 1993; vakarcs et al., 1994; vakarcs, 1997; sacchi et al., 1999), whereas it happened in croatia during the pontian (7–5 ma). the third phase of basin evolution is represented by repeated compressional events in relation to basin inversion from the pliocene onwards (horváth, 1995; csontos et al., 2002). all of the compressional events resulted in the reactivation of former faults mainly as reverse types, and gentle folding of the overlying strata (see fig. 5 and figs. 6–9). between the areas of active uplift, subsidence continued mainly in the deepest depressions resulting in the formation of an occasionally thick pliocene–quaternary succession (horváth & cloetingh, 1996; prelogović et al., 1998; horváth & tari, 1999; lučić et al., 2001; velić et al., 2002). 3. sedimentary facies and environments an overview of the major lithostratigraphic units in the study area, their composition and contacts is given in fig. 2, with more details and description of depositional characteristics in figs. 3 and 4. the neogene to quaternary basin fill in croatia starts with egerian–eggenburgian sediments documented in the mura depression, in the hrvatsko zagorje region and in the nearby westernmost part of the drava depression. this was referred to as the “western marginal part of the pannonian basin” (lučić et al., 2001) interpreted to be the place of formation of the first depocentres, concurrent with the initial tectonic transport in the formation of the pannonian basin system. in the basal sections coarse clastics, sandstones and clays with coal were observed, deposited in paralic environments. the marine tuffaceous sandstones (“macelj sandstones”) are interpreted to be of eggenburgian age (lučić et al., 2001). these sediments were not drawn in figs. 2–4 because they belong to the end of the palaeogene basin cycle and not to the rifting of pbs. anyway, they are present only in the nw corner of the study area and we wanted to emphasize the most important similarities between the hungarian and croatian stratigraphic data. the most important of these is that the overlying ottnangian sediments are found in a much wider area – in all of the structural depressions in the southern part of the pannonian basin (figs. 3 and 4). they are usually coarse-grained clastics deposited in river-to-lake environments. lacustrine sedimentation was influenced with pyroclastics. lakes prevailed in the upper part of these successions but they still probably remained isolated until the main marine transgression occurred in karpatian times. based on the data from outcrops (e.g. between mt. psunj and mt. papuk after pavelić et al., 1998) the ottnangian lake was gradually transformed into a marine environment during the karpatian. karpatian marine sediments – composed of sandy and clayey marl with tuff intercalations – were found in the hrvatsko zagorje region in the pannonian basin, early miocene subsidence and sedimentation began as a result of the first syn-rift extensional tectonic phase (horváth & royden, 1981; tari, 1994; tari & pamić, 1998; lučić et al., 2001; pavelić, 2001). this extension was also synchronous with the major extension of two microcontinents: alcapa and tisza. subsidence from the end of the karpatian corresponds to the eastward motion and possible rotation of the tisza unit under a transtensive stress field (csontos et al., 1992, 2002; csontos, 1995). in sw hungary in the vicinity of the mecsek mts. the presence of syn-sedimentary half grabens of karpatian–badenian age was proved by several studies (pogácsás, 1984; bergerat & csontos, 1988; tari, 1992; benkovics, 1997; csontos & nagymarosy, 1998; fodor et al., 1999). following a short terrestrial period, marine deposition occurred in these depressions connected by the huge water mass of paratethys. the sea-floor had significant relief: in small, but deep depressions the palaeo-water depth often exceeded 500 m (báldi et al., 2002); these depressions were surrounded by shallow submarine platforms and an archipelago (hámor, 2001). generally in this time period, bathymetric changes were controlled principally by movements of the basin floor. the first compressional event indicates the end of rifting at about the late badenian (cf. pogácsás, 1984; tari, 1994), followed by only moderate rates of subsidence. the subsequent palaeobathymetric changes, still within the badenian, were mainly controlled by global sea level variations (báldi et al., 2002). the first early post-rift event of basin inversion took place during the sarmatian (horváth & tari, 1999) resulting in a widespread pre-pannonian unconformity. afterwards quiet and relatively slow thermal subsidence occurred (horváth & royden, 1981), coupled with uplift and erosion of the surrounding alpine– carpathian–dinaric mountain belt. this supplied huge amounts of sediment via large fluvial to deltaic systems into lake pannon (bérczi et al., 1988; szentgyörgyi & juhász, 1988; juhász, 1991, 1994), resulting in the accumulation of post-rift sedimentary successions several thousand metres thick. this unit was subdivided into several 3rd order depositional sequences (pogácsás et al, 1988; ujszászi & vakarcs, 1993; vakarcs et al., 1994; vakarcs, 1997; tóth-makk, 2003), which seemingly are in phase with global sea level changes. others argue for simple climatic correlation (sacchi et al., 1999), while a tectonically controlled stratigraphic subdivision is suggested by horváth & tari (1999). because the facies boundaries within the lacustrine succession are time-transgressive (pogácsás et al., 1988, 1993), a combination of litho-, bio-, magnetoand (seismo-) sequence stratigraphy is used to establish reliable correlation between sub basins. bypassing of the delta front through the northern part of the study area (southern transdanubia) is estimated to have occurred between 9–7 ma (late pannonian – ujszászi & vakarcs, 105saftić, velić, sztanó, juhász & ivković: tertiary subsurface facies, source rocks... brownish marls and platy marls (lučić et al., 2001). in the mura and drava depressions occasionally very thick sequences of lava and pyroclastics of andesitic to basaltic composition were documented, sometimes in two intervals (fig. 3). in sw hungary, the fish-scale bearing lacustrine clayey marl and the congeria-bearing sands represent the transition from karpatian brackish water to badenian fully marine conditions. these are overlain by coarse clastics (sands, sandstones, and conglomerates) that were deposited from foreshore to nearshore areas (the budafa formation and the overlying “regressive complex”) and by dark grey, sandy siltstones and marls (tekeres schlier) rich in foraminifera, which formed in an open marine environment (fig. 2). the thickness of the schlier rarely exceeds 200–400 m, the coeval nearshore clastics may reach 600–700 m (hámor, 2001). the tekeres schlier was generally believed to be deposited in a rather shallow environment, referred to mostly as being upper neritic or sublittoral (hámor, 1970, 2001; szentgyörgyi & juhász, 1988). recent quantitative palaeoecological analysis of foraminifera, however, proved that it was and in the central and eastern part of the drava depression (both in wells and at outcrops – pavelić, 2001). karpatian marine sedimentation was also documented in the nw marginal part of the sava depression, on the margins of mt. psunj and also in the požega valley. the first neogene sediments overlying the palaeozoic–mesozoic basement in sw hungary (in the mecsek mts. and the surrounding basins both to north, west and south) are ottnangian to karpatian terrestrial deposits – conglomerates, sandstones, siltstones, even coal-bearing clay – of large alluvial fans and lakes (fig. 3). these are interfingered with the “lower” rhyolite tuff which largely contributed to the infilling of the continental basin (hámor, 1970; tari, 1992). thick intercalations of dacite tuffs (15.3–17.4 ma – árvasós & máthé, 1992) mark the karpatian/badenian boundary. the thickest epiclastic–volcanoclastic successions can reach 500–1500 m. the early badenian sea-level rise covered the karpatian deposits in croatia. a pronounced facies differentiation is recorded by interfingering of calcarenitic biogenic sandstones, turbidites with blue-grey and fig. 3 stratigraphic column of the drava depression. 106 geologia croatica 56/1 matically decreased and is reflected in the local deposition of pyroclastics (fig. 3). following the sarmatian, the contemporaneous structural changes in the surrounding alpine–carpathian mountain belt led to the final isolation of the sea and formation of lake pannon (for the best recent summaries see magyar & geary, 1999; magyar et al., 1999a, b; müller et al., 1999). depending on the palaeogeographic position, namely the tectonically determined coeval relief of the basin floor, lake pannon sediments either conformably overlie sarmatian layers (figs. 3 and 4), or they unconformably cover older sediments, or occasionally even the crystalline basement on uplifted blocks. lake pannon deposits are described from north to south because this approximates the general direction of sediment transport and the progradation of the facies belts. the southernmost depressions (sava and partly the slavonija–srijem) were partly separated by inselbergs situated perpendicular to the main sediment transport direction (pavelić, 2001), thus the palaeogeographic situation (in sense of the basin fill directions) becomes more complex to the south. deposited in bathyal depths (báldi et al., 2002). the late badenian is represented by turritella–corbula bearing clay-marls (szilágy fm.) – up to 100 m in thickness – indicating a shallow open marine realm. the clay–marl interfingers with the lithothamnion-bearing lower and upper leitha limestones which were formed in the nearshore to littoral zone. both limestones are made up of carbonate cemented conglomerates, mollusc-bearing to oolitic calcarenites and reefs up to about 50 m thick. the badenian was the last fully marine period in the life of paratethys. the late badenian sea-level rise, as a consequence of re-opening of the indo-pacific seaway (rögl, 1996), caused flooding of uplifted blocks on many places in northern croatia. the boundary in the base of upper badenian deposits may be compared with the acknowledged middle badenian unconformity, and is considered as a syn-rift/post-rift boundary (horváth, 1995; pavelić, 2001). in northern croatia, thin sarmatian deposits are found in conformable successions. the thin-bedded calcareous marls (occasionally with some sandstones) contain a characteristic small-sized brackish faunal assemblage. in addition, varve-like laminites (lučić et al., 2001; pavelić, 2001) are also known. volcanic activity drafig. 4 stratigraphic column of the sava depression. 107saftić, velić, sztanó, juhász & ivković: tertiary subsurface facies, source rocks... silty clayey marls and siltstones are widespread all over the basin above the turbiditic succession, in connection with the approaching delta slope (algyő fm. – fig. 2). in the drava depression deltaic progradation occurred from the n–nw. fine grained slope sediments contain up to 2–40 m thick lentoid sandy intercalations of different mass flow origin. the thickness of the strongly progradational delta slope reflects palaeowater depth (pogácsás, 1984) and varies from 50 m to several hundred metres. according to reflection seismic sections the slope angle also changed from rather gentle and ramp-like, to steep in the deepest depressions (ujszászi & vakarcs, 1993). the overlying well-developed, thick sandstones were accumulated mostly on the delta front and delta plain as distributary mouth bar, channel fill or wavereworked shore-face deposits. due to the high rate of subsidence a very thick (700–1000 m) aggradational unit (újfalu fm.) was formed reflecting several episodes of minor relative lake-level oscillations. the flooded delta plain gradually gave way to an alluvial plain, on which thin-bedded, often variegated silty clays, occasionally lignites alternate with sand beds a few metres thick (zagyva fm.). the fine grained deposits are of floodplain, wet plain and shallow lacustrine (pond) origin, while sands mainly represent fluvial channel fills. the thickness of this unit is about 300– 400 m in the drava depression, but elsewhere it was considerably eroded during the pliocene (fig. 2). as illustrated in fig. 4, late miocene sediments in the southern part of the study area are generally the same as in the north, but with local differences. a pronounced unconformity was identified at the base of the pannonian sediments, as described from exposures in the region between mt. moslavačka gora and mt. psunj (blašković, 1982; blašković et al., 1984). in the northern part of the drava depression, the transgressive deposits usually begin with conglomerates of destructive coasts, fining up into nearshore sandstones, mainly above the pre-neogene basement highs (bérczi et al., 1988; szentgyörgyi & juhász, 1988). above this thin coarse-grained veneer, dark grey calcareous marls that gradually turn into clayey marls (endrőd fm. – fig. 2) of hemipelagic origin are found basin-wide, indicating a longer period of basin starvation. the clayey marl is already an indicator of the slowly approaching siliciclastic input. the colour of the marls varies from black to brown indicating an alternation of anoxic to dysoxic bottom conditions. it was found that the colour lightens towards the basement highs (szentgyörgyi & juhász, 1988). it is difficult if not impossible to estimate water depth by palaeoecological tools because a completely endemic mollusc and ostracod fauna developed in lake pannon (juhász & magyar, 1992; müller et al., 1999). despite these difficulties, the depositional environment is thought to be generally deep during this period, particularly because several series of fine-grained sandstones of turbiditic origin can be found in the immediate overlying sequence (szolnok fm.). these are supposed to be formed mainly on turbidite fan lobes and sheets (bérczi et al., 1988; pogácsás et al., 1988; szentgyörgyi & juhász, 1988; juhász, 1994). the thickness of individual sandstone bodies usually varies in the range of 3–10 m, and they are separated by 2–20 m thick intercalations of marls. the thickness of the whole turbiditic succession, however, shows great variation depending on the topography of the basin floor: it pinches out towards the basin margins and is significantly thinner above basement highs, while it can reach 1500 m in the deepest parts of the depressions (fig. 5). fig. 5 geological cross-section based on correlation of well-log data (location in fig. 1). 108 geologia croatica 56/1 sw pannonian basin where sedimentation continued in the same environments (figs. 3 and 4). infilling of the remnants of lake pannon occurred with a variety of coarse clastics mixed with clay, and lignite seams formed in delta plain marshes. these were followed by meandering river systems. as climatic change coupled with basin inversion and uplift of mountainous areas took place in the quaternary (frisch et al., 1998), not only sandstones but also gravel beds appeared as channel fills. the oldest gravels in the mura and drava river valley are the belvedere gravels (oldest quaternary or pliocene–quaternary) while the sava river brought mainly carbonate-clasts as sandy gravels only in the holocene. during the pleistocene glacial periods loess mainly accumulated in the area and there are also aeolian quartz sands deposited in the western part of the drava depression. lacustrine–marsh sediments are characteristic for the warmer periods – more detailed recent descriptions of these sediments can be found in the work of velić & saftić (1991), velić & durn (1993), velić et al. (1999) and bačani et al. (1999), where results of mainly hydrogeological explorations are used for stratigraphic interpretation. 4. neogene sedimentary megacycles the neogene to quaternary basin fill in the sw marginal parts of the pannonian basin usually has an average thickness in the range of 500–1500 m, except in the central parts of depressions where much bigger values – around 4000 m in the slavonija–srijem depression, 5500 m in the sava and mura depressions, and close to 7000 m in the drava depression are found (fig. 10). this huge sedimentary pile can be subdivided into three main sequences. the cyclic character of the neogene sedimentary successions of the region was recognized long ago (filjak et al., 1969; hámor, 1970) and the three units were later defined by šimon (1980) as the “macro-rhythms of sedimentation”. the comparable units were later named “megacycles” (velić et al., 2002), as their inferred time-span is of 6.8, 5.9 and 5.6 ma respectively (measured on the geochronological scale of rögl, 1996; cf. figs. 2, 3 and 4). each of these megacycles encompasses rocks deposited during 2nd order transgressive–regressive cycles, influenced mainly by tectonics (vail et al., 1991). the megacycles are separated by major unconformities, as follows: – base neogene unconformity, which usually separates the historically complex basement from either the early, midor even late miocene sediments. on seismic sections it is an onlap surface (figs. 6, 8 and 9); in outcrops or borehole successions it is usually covered by a transgressive lag of coarse clastics of various ages. this is usually regarded as the synrift unconformity (cf. horváth & tari, 1999), lower pannonian sediments – mainly calcareous marls and limestones (prkos or valpovo fm. – fig. 2) – were deposited in a shallow lacustrine environment (figs. 3 and 4), but there are also minor deltaic bodies along the faulted margins of depressions. the composition of these sandstones is closely associated with the underlying rocks so they are interpreted to be locally derived. in the western part of the drava depression in croatia (fig. 3) this is already the time when the first turbidite sandstones were transported from the nw (koprivnica ssts. – fig. 2), found to be lithologically identical with the overlying units. the following, mainly upper pannonian to pontian sandstone–shale sequence (ivanić grad, kloštar ivanić and široko polje formations in the sava depression – see šimon, 1973, 1980) was deposited in locally very deep troughs, especially in the western part of the drava and sava depressions. the troughs were largely isolated from the rest of the pannonian basin by islands or by subaqueous basement highs. these sediments are of fairly uniform lithological composition: a sequence of sand/sandstone (subgreywacke and calcarenite–subgreywacke) bodies interlayered with silts and marls (fig. 2). sands and sandstones are grey-coloured, with a predominance of quartz grains, and some lithoclasts (usually limestone), platy minerals and feldspar grains. the mineralogical composition of the sandstones (subgreywackes) is almost the same and is interpreted as being a consequence of an external and distant sedimentary source (in contrast to the older miocene sediments – šćavničar, 1979). the morphology of these multiple sandstone bodies indicates a turbidite fan to delta system. sedimentary transport from the n–nw resulted in progradation of firstly the turbidites and then the prodelta, delta slope to delta front clastics, with the aerial distribution of lithofacies largely influenced by the elongated shape of the depositional basins. a depositional model was constructed with the source of sediments in the alps, and transport by turbidity currents (šimon, 1980). in this process, coarser grains were deposited in the deepest parts of the depressions and fine-grained material at the basement highs. in the upper pannonian sediments of the western sava depression this was later confirmed by the investigations of vrbanac (2002a, b), substantiated by a large data set of core investigations. analysing the aerial distribution of the lower pontian turbidites in the western part of the sava depression saftić (1998) confirmed that regionally recognisable e-log markers delimit numerous sandstone members as genetic units. the markedly uniform petrographic composition of both sandstones and marls, together with their sedimentological characteristics, are congruent with the external sedimentary source. more detailed dating of highresolution units still remains a problem nevertheless, it appears that the deltaic environment was formed almost ubiquitously in the late pontian, except in the deepest parts of the sava depression. during the pliocene and partly in the pleistocene, there remained several deep or shallow lakes in the 109saftić, velić, sztanó, juhász & ivković: tertiary subsurface facies, source rocks... however, the onlapping younger deposits (e.g. late miocene) indicate that this surface is often a composite unconformity. the following basal late badenian unconformity is usually considered to be the syn-rift/ post-rift boundary (royden & horváth, 1988; tari, 1994; horváth, 1995; vakarcs, 1997; pavelić, 2001). it is not as straightforward to identify seismically as the younger one. – the base pannonian is the next major unconformity. lake pannon deposits are onlapping either the basement (figs. 5 and 9) or older miocene deposits (figs. 6–8) with a transgressive lag (pogácsás et al., 1988; szentgyörgyi & juhász, 1988; hámor, 2001). seismic sections clearly reveal the erosional character of this surface, as it cuts the previously tilted badenian–sarmatian successions (figs. 5 and 8). the base pannonian unconformity is a result of uplift and erosion caused by the first compressional (inversion) event, proved both by seismic and outcrop-scale structural data (tari, 1994; horváth & tari, 1999; csontos et al., 2002). – the base pliocene unconformity seems to be the result of another compressional event, generating both uplift of the pre-existing basement highs with the overlying lake pannon deposits, formation of new highs and subsidence between these areas. thus sediments above this unconformity are onlapping in character (figs. 5, 6, 8 and 9). in areas of continuous subsidence an uninterrupted miocene–pliocene sedimentation is recorded. even a fifth, quaternary unconformity exists, as the reflection of the youngest basin-wide and local quaternary uplift/compressional event (dunkl et al., 1994; tomljenović & csontos, 2001; csontos et al., 2002). in some places it can be well observed on seismic sections (fig. 6). a description of the main characteristics of distribution/composition of rock units grouped in the three megacycles follows, illustrated by thickness maps (figs. 10–13). 4.1. terrestrial to marine deposits (base neogene – top sarmatian) the succession from the base neogene unconformity to the erosional top of the sarmatian sediments is referred to as the 1st megacycle, which is the sedimentary response to syn-rift and early post-rift structural evolution of the pannonian basin. on the thickness map of this unit (fig. 11) the darkest spots mark regions where all the underlying older formations are exposed. these range from the oldest, palaeozoic crystalline rocks, through a variety of mesozoic formations (mostly in the inselbergs) to the youngest pre-basinal unit – cretaceous–eocene flysch in the contact zone with the inner dinarides (w of varaždin – “vz” and se of karlovac – “ka”). areas where the thickness exceeds 1 km are fig. 6 section a – western sava depression (see location in figs. 10–13). 110 geologia croatica 56/1 5 avanić, r., pavelić, d. & kovačić, m. (1995): građa površinskih ekvivalenata formacija ivanić-grad, kloštar ivanić i široko polje.– unpubl. report, ina–naftaplin archive, zagreb. 6 pikija, m. & šikić, k. (1996): stratigrafsko-facijesna interpretacija naslaga miocena (zaključno sa sarmatom) dravske potoline.– unpubl. report, ina–naftaplin archive, zagreb. 7 pikija, m. & šikić, k. (1999): stratigrafsko-facijesne odlike starijeg i srednjeg miocena murske depresije i obodnih područja.– unpubl. report, ina–naftaplin archive, zagreb. the deepest troughs, thus the thickest successions, are found in the northern part of the drava depression (fig. 11, also sections in figs. 5 and 9). these half grabens are thought to be associated with stretching of large lithospheric units during eastward motion and rotation (csontos et al., 1992; csontos, 1995; csontos & nagymarosy, 1998). mainly neutral–acidic volcanism was related to the stretching, filling the half grabens with lavas and volcanoclastics up to a thickness of 1500 m. a series of partly isolated depocentres scattered along the southern margin of the present drava depression and along the northern margin of the sava depression are also remarkable. these occur along the strike of the major longitudinal fault systems along which rifting started in ottnangian times (tari, 1994; horváth, 1995; tari & pamić, 1998; horváth & tari, 1999; fodor et al., 1999; pavelić, 2001). the strong influence of tectonics on sedimentation in the syn-rift phase resulted in a variety of depositional settings and lithofacies. obviously, 3rd order depositional sequences – not to be discussed here – are tectonically overprinted (cf. báldi et al., 2002). in the croatian part of the study area, lithological composition and depositional characteristics of the 1st megacycle are described based on the maps and reports from the ina archives (avanić et al., 19955 and pikija & šikić, 19966, 19997). ottnangian freshwater coarse clastics were found throughout the drava depression, all around the slavonian mts. (papuk, krndija and psunj), and also in the western sava depression. karpatian marine sediments were documented in the eastern drava depression, at outcrops in practically all mountains of northern croatia and nw of the mecsek mts. in hungary. at about the karpatian/badenian boundary, huge areas became inundated by normal salinity sea water and the former terrestrial depocentres became the loci of the deepest (bathyal) basins. due to this early badenian sea-level rise the majority of the 1st megacycle consists of badenian rocks. upper badenian coastal to shallow marine deposits are found around the coeval basement highs: lithothamnion and bioclastic limestones prevail in the western part of the study area; conglomerates in the centre and extending to the slavonija–srijem depression; while marls are found on the slopes and in the central parts of all the depressions. the youngest part of the 1st megacycle is the sarmatian, mainly conformably overlying badenian sediments in many places throughout the study area. the basin was then starved loci of the main depocentres and are shaded by grades of light grey. fig. 7 section b – central sava depression (location in figs. 10–13). 111saftić, velić, sztanó, juhász & ivković: tertiary subsurface facies, source rocks... fig. 8 section c – bjelovar sag and drava depression (location in figs. 10–13). fig. 9 section d – northern part of the drava depression (location in figs. 10–13). u t:: o .... o cd rj) (s) .lm.l z o c: o .... o q) en (s)lml 112 geologia croatica 56/1 graphic units which start with turbidites, followed by progradation of deep-water deltas gradually shallowing up to the alluvial sediments. 4.3. inversion-related lacustrine to fluviatile deposits (base pliocene – surface) sediments of the 3rd megacycle are found only in those depressions which are situated between the most elevated basement units. they begin with lacustrine deposits and marshes in the remnants of lake pannon in pliocene times. fluvial beds become more frequent in the pleistocene (in the drava river valley) and holocene (sava river valley). the end of the cycle is marked by gravels, loess and unconsolidated surface layers (figs. 2–4). as illustrated in fig. 13, the thickness of this unit is negligible in hungary (below 200–300 m), but reaches well over 1000 m in several places to the south. local thickness variations can be quite abrupt, producing differences in relatively closely spaced seismic sections (compare the ne end of section c in fig. 8 with the southern end of section d in fig. 9). in the central part of the sava depression, over 1500 m were drilled and the sequence reaches 1800 m in the central drava depression between the slavonian mts. and the mecsek–villány mts. contacts with underlying rocks are frequently marked with onlaps (section a, fig. 6; section d, fig. 9), and there are regions where these sediments cover all the older neogene rocks and directly overlie palaeozoic rocks (n and w slopes of mt. moslavačka gora). as a rule, in comparison to the previous megacycle the depocentres are shifted in a southerly direction (western sava) or to the se (bjelovar sag and central drava depression). different relationships were determined in the eastern part of the study area where areas of the maximal thickness of the 2nd and 3rd megacycles either overlap each other (eastern drava and slavonija–srijem depression), or there is a local shift of the depocentre in a westerly direction (eastern sava – s of mt. psunj). 5. hydrocarbon potential 5.1. source rocks within the neogene basin fill studies of hydrocarbon source rocks in the pannonian basin were intensified in the last two decades of the 20th century. a number of papers were published both in croatia and in hungary by the joint efforts of organic geochemists and petroleum geologists (barić & radić, 1988; dank, 1988; horváth et al., 1988; kőrössy, 1988, 1989; barić et al., 1989; putniković et al., 1989; radić et al., 1989; alajbeg et al., 1990; szalay & koncz, 1991; clayton & koncz, 1994; hernitz et al., 1995a; horváth & tari, 1999). neogene source rocks with type ii and iii kerogen content were deposited as marine or lacustrine clays from the sediment supply and was later strongly eroded on some elevated blocks, so the sarmatian unit is rarely thicker than 50 m. these layers were mostly deposited in a shelf environment with occasional coastal influence along the southern margin of the sava depression and ne of mt. krndija. the offshore sarmatian sediments were documented in the southern and western marginal parts of the pannonian basin, i.e. ne of karlovac (“ka”), w of krapina (“kr”), as well as in the eastern part of the sava depression. during the late badenian very rapid subsidence ceased, only slow post-rift subsidence occurred. at the end of the sarmatian the first very pronounced compressive event resulted in rejuvenation of former extensional structural elements in a compressive regime (cf. tari & pamić, 1998; horváth & tari, 1999; csontos et al., 2002). some basement blocks were uplifted and to a various extent erosion of the syn-rift and early post-rift strata took place (figs. 6 and 8). 4.2. lacustrine, deltaic to alluvial deposits (base pannonian – top pontian) sediments of the 2nd megacycle were all deposited in lake pannon during an interval of thermal subsidence that followed rifting (horváth & royden, 1981; royden & horváth, 1988; horváth & tari, 1999). as subsidence commenced after the basin inversion, the “lacustrine” transgression quickly inundated both the wide depressions and the basement highs. as a result, a large underfed lake with an inherantly uneven basin floor topography was born (šimon, 1973, 1980; bérczi et al., 1988; kőrössy, 1989). the thickness of the 2nd megacycle (fig. 12) varies from 2000 m (western sava depression) through 3000 m north of the iharosberény high, to 4–5000 m along the sw margin of the drava depression. as a rule, the maximum thickness is close to basin margin faults. these are also the places where sandstones of turbiditic origin show their maximum thickness (cf. fig. 5). turbidites, accumulating mainly in the deepest depressions, particularly in front of, and on the slopes of basement highs, gradually levelled the basin floor topography. above the turbidites deltaic progradation fed from the n, nw occurred. due to persisting high rates of subsidence coupled with enormous rates of sediment supply, delta front-, delta plain-, coastal plainto alluvial plain-series accumulated mainly in an aggradational style (figs. 2–4), resulting in a relatively large uniform thickness. in the northern part of the drava depression, the top of the successions infilling lake pannon were eroded mainly above the previously existing basement highs (figs. 5 and 9), suggesting rejuvenation of former structural elements again in a reverse sense (cf. csontos et al., 2002). according to the present regional seismic interpretation in the sava depression (ivković et al., 2000), the entire pannonian to quaternary sequence can be subdivided into 6 seismostrati113 s aftić, velić, s ztanó, juhász & ivković: tertiary s ubsurface facies, s ource r ocks... fig. 10 isopach m ap of the entire n eogene to q uaternary sequence w ith h c accum ulations. on 171 ~ 6300000 , thickness of ng+q basin fill ~2;1'\ 5~~o/ 0==~ (depth of pre-rift palaeozoic-mesozoic basement) ~-~~'-1.s ........ ............. + \ ~-) o scale 50km co~ined seismic sactidn~"-"'-, i i borders i m i oil field i c;::,1 oil and gas field i i gas field 6400000 6450000 6500 000 114 geologia croatica 56/1 115saftić, velić, sztanó, juhász & ivković: tertiary subsurface facies, source rocks... and marls. the source rocks are dark grey to black marls, calcareous marls, clayey limestones, siltstones and shales. in these sediments the organic matter usually appears uniformly dispersed in the matrix, but it can also be found in the form of lenses, bands or as centimetre to millimetre thick laminae. these source rocks were deposited during the 1st and in the beginning of the 2nd megacycle – mostly between the base neogene and the lake pannon turbiditic successions. they were formed mainly during the karpatian and badenian, and a minor portion during the sarmatian and early pannonian (figs. 3 and 4). according to szalay & koncz (1991), in the hungarian part of the basin, the oil generation window is situated between 2.4–4.3 km, while toc averages 1–2 wt.% (up to 5 wt.%). there are type ii and iii kerogens, thus both oil and gas generation have occurred. in the southern part of the study area (in croatia) there is a local variation in composition of organic matter. two main types appear – either the hydrogen-rich kerogen type ii (liptinite) mixed with some type i (alginite), or kerogen type iii (vitrinite). both types originate from the bacterially altered marine algal–lipid matter more or less mixed with terrigenous matter and deposited in the dysoxic–anoxic environment of the bottom waters. the source rocks are mostly mature, because they reached the conditions for expulsion at depths exceeding 2000 m and temperatures of over 100ºc. oil–source correlation determined that the c13/c12 isotope ratio of the above source rocks has the same value in oils of the area, which means that the analysed hydrocarbons really originate from the described source rocks (putniković et al., 1989; radić et al., 1989; hernitz et al., 1995a). when compared to the produced quantities and the total hc reserves, the middle miocene source rocks are evaluated as being thick enough and having a very good generation potential. the situation in the western part of the drava depression in croatia is different because of the presence of large gas and gas condensate fields (fig. 10). these are the deepest reservoirs of the pannonian basin in croatia. according to barić et al. (1992) the sediments rich in organic matter are found there in two intervals. the older one is of early miocene age (fig. 3) and contains siltstones and mudstones at a depths of 3200–4500 m. hydrogen indices are significantly reduced – this is the kerogen type iii, and rocks are presently in the phase of increased thermal maturity (mature to over-mature) and capable of generation of dry and wet gas and gas condensate. it was found that part of the source rocks from this interval has generated only dry gas, which is thermally highly altered. the younger interval of source rocks in this area is formed of badenian sediments and pannonian fossiliferous calcareous marls at a depth of 2000–3000 m. optical analyses of the maceral composition of kerogen, revealed predominance of vitrinite and debris of wood structure, as well as sporadic concentrations of exinite which, of course, originate from the land, but which were deposited in lacustrine anoxic conditions. these rocks are presently situated within the oil window. there are also older, pre-neogene source rocks in the nearby parts of the pannonian basin. in the hungarian zala basin, in the nw part of the study area, two– three types of oils were identified by isotopic, chemical and biological signals, which indicate that the upper triassic black shales (kössen marl) were the main source rocks, and that miocene source rocks produced only minor amounts. oil generation and expulsion both from triassic and miocene source rocks began during the late miocene extension (clayton & koncz, 1994). in the drava basin this kössen marl cannot be found in the pre-neogene basement, therefore the main source rocks must be of neogene age, but that does not mean that similar future findings can be ruled out, especially in the contact zone of the dinarides and eastern alps. in the same area, there are the remnants of the slovenian trough with lots of flysch sediments and also cretaceous–palaeogene flysch sediments under the most western part of the sava depression – but this is beyond the scope of this paper. 5.2. main petroleum reservoirs matured hydrocarbons migrated along the major unconformities and fault zones from the deepest parts of the depressions towards the structural traps situated usually above the basement highs or in en-echelon folds in the vicinity of the most faulted margins of the depressions. neogene sand beds in folded and compacted anticlines over basement highs are the most obvious hydrocarbon traps (kranjec, 1972; dank, 1988). occasionally the fractured basement together with the generally overlying basal conglomerates bears hydrocarbons. stratigraphic traps are difficult to find and only minor occurrences of this type have been discovered. most of the reservoirs are within the 1st and 2nd megacycles – ottnangian breccias, karpatian, badenian or pannonian basal conglomerates and lake pannon prodelta turbiditic lobes, sand sheets, slumps, delta front mouth bars and delta plain channel fills have the most favourable reservoir characteristics (figs. 3 and 4). the seals are usually provided by the associated intralobe mudstones or interdistributary clays. the most important lithostratigraphic units are illustrated in fig. 2, details can be found in the works of šimon (1973) and kőrössy (1989). the oldest coarse-grained clastic member of the ivanić grad formation – iva sandstones, contains 30% of the total discovered hc reserves in croatia. most thoroughly investigated in the sava depression (vrbanac, 2002b), it was deposited in a deep basinal, prodelta environment. this finding can be extrapolated in other sub-basins. more detailed descriptions can be found in the works of đureković (1995), kovačević (1996), larva (1996) and matasović (1996) and also the first part of this paper. the most important characteristic for hc accumulation in this unit is that porosity varies from 114 g eologia c roatica 56/1 115 s aftić, velić, s ztanó, juhász & ivković: tertiary s ubsurface facies, s ource r ocks... fig. 11 isopach m ap of the 1st m egacycle. ~ § § ~ .... ~ j i~' ( ;ii''' zu.,. , 0 !.. kr .... :, ... ,. ! ~i ~, .... c<:\\, con1tjined seismic sections~ 6350000 '. ". r--~--.: : .f' j. .(" ,.', .' ,i ;. ...... .,.... ...... -:~/. (~:/.);. ,. 6400 000 6450000 10t megacycle terrestrial to marine deposits (base neogene base pannonian) .. i' 6500000 • rc;{--" .,.,-t;~ (,. ..... ..... _! ......... /'. , {;~;! '. c', ,-. \ i ....... :. \. f' . . -.6600 000 116 g eologia c roatica 56/1 117 s aftić, velić, s ztanó, juhász & ivković: tertiary s ubsurface facies, s ource r ocks... fig. 12 isopach m ap of the 2nd m egacycle. 8 ~ ~ o scale solan ! ! 6400000 6450000 2nd megacycle lacustrine deltaic alluvial deposits (base pannonian base pliocene) .. .. "" 6550000 116 g eologia c roatica 56/1 117 s aftić, velić, s ztanó, juhász & ivković: tertiary s ubsurface facies, s ource r ocks... fig. 13 isopach m ap of the 3rd m egacycle. !5 ~ bj 0 8 ? scai,e ~okm borders 6 350 000 6400 000 6450000 3'd megacycle inversion-related lacustrine to terrestrial deposits (base pliocene surface) .. • '" ~ ~~ o. o ------------o.~ c::-'-:;---, . , ~ o· ; \.,1 "'; ..... _! ......... /'. i~?~j '-, \., .... ~.,. ( ... ~,._.ri._ ..... , dj{"---' ". , (~ 0'-'_. ' . 2p 9 6500000 ._-.... .;;~: ... ;: ,~j 0' .... _ . ..,. " ._.l'.~.~. + "'o.s" 6 550 000 8 ..... _ ..... ) -\ > .. --.... 000 118 geologia croatica 56/1 119saftić, velić, sztanó, juhász & ivković: tertiary subsurface facies, source rocks... 11% to 25% and even 30%. it was also determined that porosity declines with depth, mainly because of compaction and because the ratio of the silt-sized grains increases in this direction. the horizontal permeability was also measured on cores and it is between 0.1x10-3m2 and 380x10-3m2. reservoir characteristics usually vary over relatively short distances, which must be precisely defined in order to obtain a better recovery ratio, especially in the phase of secondary production (injection of water or gas) or in the planned tertiary production methods. the drava depression is both the largest and the deepest sub-basin in the study area. the deepest part lies between virovitica and slatina (“vi” and “sl” in fig. 10), where the thickness of neogene and quaternary sediments can reach 7000 m. in the croatian part of the drava depression, 30 gas and oil fields were discovered, of which 23 are presently producing oil, gas condensate or gas. in the western part of the drava depression, the hc traps are within conglomerates and sandstones of the lower and middle miocene (1st megacycle) and pannonian sandstones (basal part of the 2nd megacycle). above, the lower pontian sandstones also have good reservoir properties. nevertheless, the most valuable hydrocarbon accumulations are in the fractured palaeozoic and mesozoic rocks with secondary porosity; the reservoirs at molve and kalinovac (“m” and “k” in fig. 10) are the largest gas and gas condensate fields in croatia. in the eastern part of the drava depression, the largest hc accumulation is the beničanci oil field (marked with “b”, where more than 18x106m3 of oil has been produced since 1972). here the reservoir rocks are middle miocene basal carbonate breccias with excellent petrophysical properties (hernitz et al., 1995b). according to tišljar (1993), the beničanci reservoir is composed of wedge-shaped bodies of rockfall and debris breccias, formed by the accumulation of large masses of dolomite detritus from the shore zone. the cliffs of the steep shoreline were situated along the margins of the faulted dolomite massif that was gradually uplifted. in this unit there are also thinner bodies of breccias, conglomerates and sandstones built up by detritus of coral reefs (velić et al., 2000). they were also deposited in the shoreline zone during the early badenian sea-level rise and subsequent late badenian transgression. on the hungarian side of the drava depression two basement highs are of primary interest: the inke–iharosberény high at the north-western part of the basin and the görgeteg–babócsa high to the south (fig. 10). görgeteg is also a historical place, because the first well log measurements in hungary were carried out here in 1935. in this area both oil and gas bearing rocks are confined to lake pannon turbiditic sand sheets and in one example to a delta plain channel-fill sandstone. the excellent reservoir quality sandstones of the delta front and delta plain hardly ever contain traps because there are no good seals in the extremely thick wavereworked, delta-front successions. not far from görgeteg a minor oil pool was also found in the badenian leitha (rákos) limestone, and north of the high, minor indications of oil reservoirs were detected in badenian (tuffaceous) sandstones, and conglomerates of shallow marine origin. south of the main görgeteg high, a minor anticline was found, in which gas reservoirs are situated at the top of the palaeozoic basement and in the overlying badenian transgressive coarse clastics. at the inke high small isolated sand bodies of badenian to lower pannonian are producing minor amounts of gas. in addition, occasionally the top of the fractured triassic carbonates is a co2–ch4 reservoir. between the two major highs, the somogyudvarhely–gyékényes depression is found, which acted rather as a source area; here both the fractured crystalline basement and the overlying karpatian to badenian sandstones contain indications of oil and co2 (kőrössy, 1989). the mura depression is in the nw part of the study area. the most valuable hydrocarbon reservoirs in the southern part of it occur in breccias, conglomerates and sandstones of the early and middle miocene, and lake pannon sandstones of different depositional facies. reservoir rocks were deposited in a variety of depositional settings, ranging from the subaqeous slumps and turbidites (ottnangian–badenian) to flood plain and slope lithoarenites and biocalcarenites, mixed with siliciclastic detritus that were formed in the vicinity of patch reefs (mostly badenian). the described sediments form hc reservoirs of several smaller and two larger fields – veliki otok and legrad (“vo” and “l” in fig. 10) which, according to the cumulative production, are amongst the 10 largest gas fields in croatia. similarly to the hungarian part of the drava depression, quite large, but co2-rich gas accumulations were recently discovered in the triassic basement highs in the very nw corner of the study area, close to the border with slovenia. the slavonija–srijem depression in the se corner of the study region is relatively shallow and covers the smallest area. only the western part lies in croatia, where the entire neogene–quaternary sedimentary and volcanic succession has a maximum thickness of 4000 m (fig. 10). three hc fields were discovered in this area, with relatively shallow reservoirs (approx. 1000 m) formed of the fractured and weathered palaeozoic and mesozoic rocks together with overlying lower and middle miocene clastics (1st megacycle). the sava depression lies along the sw margin of the pannonian basin and the thickest sequence of the neogene–quaternary sediments (over 5000 m) can be found in its central part, s of mt. moslavačka gora (fig. 10). the most important reservoir rocks are pannonian and pontian sandstones which start with the transgressive locally sourced sandstones, soon pass into turbidites and end with large masses of deltaic sediments (mostly sandstones). there are hc reservoirs also in the weathered and fractured palaeozoic granite and gneiss of the covered western slopes of mt. moslavačka gora, 118 geologia croatica 56/1 119saftić, velić, sztanó, juhász & ivković: tertiary subsurface facies, source rocks... but the most important fields are in neogene reservoirs – stružec, žutica and okoli fields (marked with “s”, “ž” and “o” in fig. 10). 6. conclusions 1) in the neogene sedimentary succession three depositional megacycles can be identified in the sw part of the pannonian basin. each encompasses rocks deposited during 2nd order cycles influenced mainly by the structural evolution of the basin. the megacycles are separated by major unconformities – the base neogene, the base pannonian and the base pliocene unconformities, which usually separate the onlapping deposits of the younger cycle from uplifted, tilted and eroded older rocks. these uplifts interrupting basin subsidence reveal compressional events in association with inversion tectonics. such a subdivision is suitable for the subsurface geological data, in the sedimentary record the actual syn-rift/post-rift boundary is identified as the prominent unconformity in the base of the late badenian sediments. even a fifth, quaternary unconformity exists, as the reflection of the youngest uplift of the mountainous areas. 2) the 1st megacycle is composed of early to middle miocene syn-rift and early post-rift sediments. terrestrial sandstones, subordinate coal seams, coastal talus breccias, conglomerates and sandstones are overlain by shallow to deep marine marls and shales of varying carbonate content and with thin sandy intercalations, while biogenic and bioclastic limestones were formed in the nearshore zone. the end of the megacycle is characterised mostly by fine-grained deposition in the starved brackishwater basin. 3) the 2nd megacycle is connected to the thermal subsidence of the late miocene pannonian basin, thus is built up by the post-rift sediments of lake pannon. apart from local variations due to prepannonian topography the sedimentary succession begins with littoral limestones and a nearshore transgressive lag overlain by hemipelagic calcareous and clayey marls basin-wide. the deepest depressions were filled by lacustrine turbidite lobes and channel fills of considerable thickness, thus the initial basin floor topography gradually became levelled. turbiditic successions are overlain by shale-prone delta slope and sandy delta front to coastal plain sediments. the northern part of the drava depression was filled to lake level and the youngest deposits of this megacycle were formed in fluvial environments. to the south, deposition continued on the delta front and in the prodelta region respectively. 4) the 3rd megacycle was formed during pliocene to quaternary basin inversion resulting in subsidence in the deepest zones, associated with uplift and erosion of the most elevated blocks. at that time lake pannon occupied only the southern part of the study area where basin fill up to fluvial deposits continued in a similar manner as previously occurred. 5) the main source rocks with type ii and iii kerogens are middle miocene marine clays and marls and upper miocene hemipelagic marls of lake pannon. they generally occur in the oil generation window or in the wet and dry gas zone depending on their present-day position in the basin. 6) the main hydrocarbon reservoirs are above structural highs in the studied basins, either in the fractured neogene basement, associated with basal conglomerates and sandstones, or in the neogene sedimentary succession. lower to middle miocene coarse clastics – rockfall breccias composed mostly of mesozoic dolomite fragments, conglomerates and sandstones accumulated in the coastal to shallow marine zones during the badenian, form reservoirs with good characteristics. the most important reservoirs, however, are sandstone bodies of different (turbiditic or deltaic) origin within the upper miocene 2nd megacycle. their reservoir characteristics are highly variable. acknowledgements we are indebted to lászló csontos for discussions on structural events and also for providing some unpublished data. imre magyar is thanked for helping us with the lake pannon stratigraphy and for having read the manuscript with the utmost care. davor pavelić and boris vrbanac kindly helped us in correlation/ interpretation of the data acquired from the surface with the subsurface data sources. for discussions regarding the pannonian basin development in croatia we are thankful to jožef šimon and eduard prelogović. financial support was provided by the croatian ministry of science and technology (scientific project no. 0195035) and by hungarian scientific research grants (otka) nos. t 037724 and t 035168. 7. references alajbeg, a., britvić, v., švel-cerovečki, s., cornford, ch., todorić, a., rajković, j., barić, g. & putniković, a. (1990): geochemical study of the oils and source rocks in the pannonian basin.– organic geochemistry, 16, 339–352. árva-sós, e. & máthé, z. (1992): mineralogical and petrographic study of some neogene layers of the mecsek mts. (south hungary) and their k–ar dating.– földtani közlöny, 35/2, 177–192. bačani, a., šparica, m. & velić, j. (1999): quaternary deposits as the hydrogeological system of eastern slavonia.– geol. croatica, 52/2, 141–152. 120 geologia croatica 56/1 121saftić, velić, sztanó, juhász & ivković: tertiary subsurface facies, source rocks... báldi, t. (1980): the early history of paratethys (in hungarian with english abstract).– földtani közlöny, 110/3–4, 456–472. báldi, k., benkovics, l. & sztanó, o. (2002): badenian (middle miocene) basin development in sw hungary: subsidence history based on quantitative paleobathymetry of foraminifera.– int. j. earth. sci., 91, 490–504. barić, g. & radić, j. (1988): identifikacija materinskih porod jugozapadnoj časti pannonskogo baseina, dinaridov i adriatičeskogo podmorja.– petrolgeohim, dokladi po geohimičeskim vaprosam, 1, 155–165, szolnok. barić, g., maričić, m. & radić, j. (1989): geochemical correlation of source rocks and oils in southern margins of pannonian basin.– 14th international meeting on organic geochemistry, abstracts, 218, paris. barić, g., mesić, i. & jungwirth, m. (1992): sedimentary and geochemical characteristics of rocks and fluids of the western part of the drava depression.– nafta, 43/4–5, 225–238, zagreb. benkovics, l. (1997): etude structurale et géodynamique des monts buda, mecsek et villány (hongrie). thèse de doctorat (structural and geodynamic study of the buda hills, mecsek and villány mountains, in french with english and hungarian summary).– unpubl. phd thesis, university of lille, 230 p. bérczi, i., hámor, g., jámbor, á. & szentgyörgyi, k. (1988): neogene sedimentation in hungary.– in: royden, l.h. & horváth, f. (eds.): the pannonian basin – a study in basin evolution. aapg memoir, 45, 57–67. bergerat, f. & csontos, l. (1988): brittle tectonics and paleo-stress field in the mecsek and villány mts. (hungary): correlation with the opening mechanism of the pannonian basin.– acta geol. hung., 31/1–2, 81–100. blašković, i. (1982): the neogene of the ilova river depresssion (northern croatia).– acta geologica, 12/2, 23–67, zagreb. blašković, i., tišljar, j., dragičević, i. & velić, j. (1984): razvoj sedimentacijskih okoliša miocenskih naslaga na zapadnim obroncima psunja (sjeverna hrvatska).– geološki vjesnik, 37, 11–32. clayton, j.l. & koncz, i. (1994): petroleum geochemistry of the zala basin, hungary.– aapg bull., 78/1, 1–22. csontos, l. (1995): tertiary tectonic evolution of the intracarpathian area.– acta vulcanologica, 7, 1–13. csontos, l. & nagymarosy, a. (1998): the mid-hungarian line: a zone of repeated tectonic inversions.– tectonophysics, 297, 51–71. csontos, l., nagymarosy, a., horváth, f. & kovač, m. (1992): tertiary evolution of the intra-carpathian area: a model.– tectonophysics, 208, 221–241. csontos, l., benkovics, l., bergerat, f., mansy, j-l. & wórum, g. (2002): tertiary deformation history from seismic section study and fault analysis in a former european tethyan margin (the mecsek–villány area, sw hungary).– tectonophysics, 297, 51–71. dank, v. (1988): petroleum geology of the pannonian pasin, hungary: an overview.– in: royden, l. & horváth f. (eds.): the pannonian basin – a study in basin evolution. aapg memoir, 45, 319–331. dunkl, i., árkai, p., balogh, k., csontos, l. & nagy, g. (1994): a hőtörténet modellezése fission track adatok felhasználásával – a bükk hegység kiemelkedéstörténete.– földtani közlöny, 124/1, 1–24. đureković, m. (1995): taloženje i rezervoarska obilježja iva-pješčenjaka na naftnom polju ivanić.– unpubl. msc thesis, university of zagreb, 59 p. filjak, r., pletikapić, ž., nikolić, d. & aksin, v. (1969): geology of petroleum and natural gas from the neogene complex and its basement in the southern part of the pannonian basin, yugoslavia.– conference of the institute of petroleum and aapg, brighton, 1969, 113–130. fodor, l., csontos, l., bada, g., györfi, i. & benkovics, l. (1999): tertiary tectonic evolution of the pannonian basin system and neighbouring orogens: a new synthesis of palaeostress data.– in: durand, b., jolivet, l., horváth, f. & séranne, m. (eds.): the mediterranean basins: tertiary extention within the alpine orogene. geol. soc. london, spec. publ., 156, 295–334. frisch, w., kuhlemann, j., dunkl, i. & brügel, a. (1998): a palinspastic reconstruction and topographic evolution of the eastern alps during the tertiary tectonical evolution.– tectonophysics, 297, 1–15. hámor, g. (1970): the miocene of the east mecsek mts (in hungarian).– ann. inst. geol. hung., 53/1, 1–483. hámor, g. (2001): miocene palaeogeography of the carpathian basin: explanatory notes to the miocene palaeogeographic maps of the carpathian basin 1:3.000,000.– publication of the geological institute of hungary, budapest, 71+vii p.. hernitz, z., velić, j. & barić, g. (1995a): origin of hydrocarbons in the eastern part of the drava depression (eastern croatia).– geol. croatica, 48/1, 87–95. hernitz, z., velić, j., kalac, k. & saftić, b. (1995b): miocenske taložine u širem području beničanaca i njihovo naftnogeološko značenje (istočna hrvatska).– in: vlahović, i., velić, i. & šparica, m. (eds.): first croatian geological congress, opatija, 1995, proceedings, 1, 195–200. horváth, f. (1993): towards a mechanical model for the formation of the pannonian basin.– tectonophysics, 225, 333–358. horváth, f. (1995): phases of compression during the evolution of the pannonian basin and its bearing on hydrocarbon exploration.– marine and petroleum geology, 12, 837–844. horváth, f. & cloetingh, s. (1996): stress-induced late-stage subsidence anomalies in the pannonian basin.– tectonophysics, 266, 287–300. horváth, f. & royden, l.h. (1981): mechanism for formation of the intra-carpathian basins: a review.– earth evol. sci., 1/3–4, 307–316. horváth, f. & tari, g. (1999): ibs pannonian basin project: a review of the main results and their bearings on hydrocarbon exploration.– in: durand, b., jolivet, l., horváth, f. & séranne, m. (eds.): the mediter120 geologia croatica 56/1 121saftić, velić, sztanó, juhász & ivković: tertiary subsurface facies, source rocks... ranean basins: tertiary extension within the alpine orogen. geol. soc. london, spec. publ., 156, 195–213. horváth, f., dövényi, p., szalay, á. & royden l.h. (1988): subsidence, thermal and maturation history of the great hungarian plain.– in: royden, l. & horváth, f. (eds.): the pannonian basin – a study in basin evolution. aapg memoir, 45, 355–375. ivković, ž., matej, s. & škoko, m. (2000): seizmostratigrafska interpretacija gornjomiocenskih i pliocenskih sedimenata savske depresije (seismostratigraphic interpretation of upper miocene and pliocene sediments of the sava depression).– in: vlahović, i. & biondić, r. (eds.): second croatian geological congress, cavtat – dubrovnik, 2000, proceedings, 219–222 (in croatian with english abstract). juhász, gy. (1991): lithostratigraphical and sedimentological framework of the pannonian (s.l.) sedimentary sequence in the hungarian plain (alföld), eastern hungary.– acta geologica hungarica, 34/1–2, 53–72. juhász, gy. (1994): comparison of the sedimentary sequences in late neogene subbasins in the pannonian basin, hungary (magyarországi neogén medencerészek pannóniai s.l. üledéksorának összehasonlító elemzése).– földtani közlöny, 124/4, 341–365. juhász, gy. & magyar, i. (1992): a pannóniai (s.l.) litofáciesek és molluszka-biofáciesek jellemzése és korrelációja az alföldön (review and correlation of the late neogene (pannonian s.l.) lithofacies and mollusc biofacies in the great plain, eastern hungary).– földtani közlöny, 122/2–4, 167–194. kőrössy, l. (1988): hydrocarbon geology of the zala basin in hungary.– general geological review, 23, 3–162. kőrössy, l. (1989): hydrocarbon geology of the dráva basin in hungary.– general geological review, 24, 3–122. kranjec, v. (1972): subsurface structures in the sava and drava river depressions and their classification.– bull. sci. cons. acad. yougosl., (a), 17/11–12, 362–363, zagreb. kovačević, a. (1996): iva-pješčenjaci na naftnom polju ježevo.– unpubl. bsc thesis, university of zagreb, 35 p. larva, o. (1996): iva-pješčenjaci na naftno-plinskom polju voloder.– unpubl. bsc thesis, univ. of zagreb, 39 p. lučić, d., saftić, b., krizmanić, k., prelogović, e., britvić, v., mesić, i. & tadej, j. (2001): the neogene evolution and hydrocarbon potential of the pannonian basin in croatia.– marine and petroleum geology, 18, 133–147. magyar, i. & geary, d.h. (eds.) (1999): fossils and strata of lake pannon, a long-lived lake from the upper miocene of hungary.– acta geologica hungarica, 42/1, 108 p. magyar, i., geary, d.h. & müller, p. (1999a): paleogeographic evolution of the late miocene lake pannon in central europe.– palaeogeography, palaeoclimatology, palaeoecology, 147, 151–167. magyar, i., geary, d.h., sütő-szentai, m., lantos, m. & müller, p. (1999b): integrated biostratigraphic, magnetostratigraphic and chronostratigraphic correlations of the late miocene lake pannon deposits.– acta geologica hungarica, 42, 5–31. matasović, m. (1996): petrološke i sedimentološke značajke pješčanih tijela – ležišta “c” naftno-plinskog polja mramor brdo.– unpubl. bsc thesis, university of zagreb, 33 p. müller, p., geary, d.h. & magyar, i. (1999): the endemic molluscs of the late miocene lake pannon: their origin, evolution, and family-level taxonomy.– lethaia, 32, 47–60. pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.– basin research, 13, 359–376. pavelić, d., miknić, m. & sarkotić šlat, m. (1998): early to middle miocene facies succession in lacustrine and marine environments on the southwestern margin of the pannonian basin system (croatia).– geologia carpathica, 49/6, 433–443. pogácsás, gy. (1984): seismic stratigraphic features of the neogene sediments in the pannonian basin.– geophysical transactions, 30/4, 373–410. pogácsás, gy., lakatos, l., ujszászi, k., vakarcs, g., várkonyi, p., várnai, p. & révész, i. (1988): seismic facies, electro facies and neogene sequences, chronology of the pannonian basin.– acta geol. hung., 31/3–4, 175–207. pogácsás, gy., müller, p. & magyar, i. (1993): the role of seismic stratigraphy in understanding biological evolution in the pannonian lake (se europe, late miocene).– geologia croatica, 46, 63–69. prelogović, e., saftić, b., kuk, v., velić, j., dragaš, m. & lučić, d. (1998): tectonic activity in the croatian part of the pannonian basin.– tectonophysics, 297, 283–293. putniković, a., britvić, v., dragaš, m. & majstorović, j. (1989): geološka interpretacija i usporedba geokemijskih podataka u svrhu sagledavanja međusobne povezanosti matičnih stijena i ugljikovodika u panonskom bazenu.– dit ina–naftaplin, 26–27, 87–94, zagreb. radić, j., britvić, v. & dragaš, m. (1989): matične stijene panonskog bazena (istražno područje ina–naftaplin).– dit ina–naftaplin, 26–27, 77–85, zagreb. rögl, f. (1996): stratigraphic correlation of the paratethys oligocene and miocene.– mitt. ges. geol. bergbaustud. österr., 41, 65–73. rögl, f. & daxner-höck, g. (1996): late miocene paratethys correlations.– in: bernor, r.l., fahlbusch, v. & mittmann, h.-w. (eds): the evolution of western eurasian neogene mammal faunas. columbia university press, new york, 47–55. royden, l.h. & horváth, f. (eds.) (1988): the pannonian basin – a study in basin evolution.– aapg memoir 45, 394 p. sacchi, m., horváth, f. & magyari, o. (1999): role of unconformity-bounded units in the stratigraphy of the continental record: a case study from the late miocene of the western pannonian basin, hungary.– in: durand, b., jolivet, l., horváth f. & séranne, m. (eds.): the mediterranean basins: tertiary extension within the 122 geologia croatica 56/1 alpine orogene. geol. soc. london. spec. publ., 156, 357–390. saftić, b. (1998): genetska stratigrafska sekvencijska analiza u pontskim naslagama zapadnoga dijela savske depresije.– unpubl. phd thesis, university of zagreb, 136 p. szalay, á. & koncz, i. (1991): genetic relation of hydrocarbons in the hungarian part of the pannonian basin.– in: spencer, a.m. (ed.): generation, accummulation and production of europe’s hydrocarbons. eapg special publication, 1, oxford, 317–322. szentgyörgyi, k. & juhász, gy. (1988): sedimentological characteristics of the neogene sequences in sw transdanubia, hungary.– acta geol. hung., 31/3–4, 209–225. šćavničar, b. (1979): pješčenjaci miocena i pliocena savske potoline.– 3. god. naučni skup sekcije za primjenu geologije, geofizike i geokemije znanstvenog savjeta za naftu jugosl. akademije znanosti i umjetnosti, novi sad 22.–24.3.1977., zbornik radova 2, 351–382, jazu, radovi zsn, serija a, knjiga 6/2, zagreb (in croatian with an english abstract). šimon, j. (1973): o nekim rezultatima regionalne korelacije litostratigrafskih jedinica u jugozapadnom području panonskog bazena.– nafta, 24/12, 623–630. šimon, j. (1980): prilog stratigrafiji u taložnom sustavu pješčanih rezervoara sava-grupe naslaga mlađeg tercijara u panonskom bazenu sjeverne hrvatske.– unpubl. phd thesis, university of zagreb, 66 p. tari, g. (1992): late neogene transpression in the northern thrust zone mecsek mts. hungary.– annales of the eötvös university budapest, sect. geol., 29, 165–187. tari, g. (1994): alpine tectonics of the pannonian basin. unpubl. phd thesis, rice university, houston, 501 p. tari, g., dövényi, p., dunkl, i., horváth, f., lenkey, l., stefanescu, m., szafián, p. & tóth, t. (1999): lithospheric structure of the pannonian basin derived from seismic, gravity and geothermal data.– in: durand, b., jolivet, l., horváth, f. & séranne, m. (eds.): the mediterranean basins: tertiary extension within the alpine orogen. geol. soc. london, spec. publ., 156, 215–250. tari, v. & pamić, j. (1998): geodynamic evolution of the northern dinarides and the southern part of the pannonian basin.– tectonophysics, 297, 269–281. tišljar, j. (1993): sedimentary bodies and depositional models for the miocene oil-producing areas of ladislavci, beničanci and obod.– nafta, 44/10, 531–542, zagreb. tomljenović, b. & csontos, l. (2001): neogene– quaternary structures in the border zone between alps, dinarides and pannonian basin (hrvatsko zagorje and karlovac basins, croatia).– int. j. earth. sci., 90, 560– 578. tóth-makk, á. (2003): szekvencia sztratigráfiai vizsgálatok a duna–tisza köze középső és déli részének késő miocén rétegsorában (sequence stratigraphy of late miocene deposits of the danube–tisza interfluve).– unpubl. phd thesis, elte budapest, 156 p. ujszászi, k. & vakarcs, g. (1993): sequence stratigraphic analysis in the south transdanubian region, hungary.– geophysical transactions, 38, 69–87. vail, p.r., audemard, f., bowman, s.a., eisner, p.n. & perez-cruz, c. (1991): the stratigraphic signatures of tectonics, eustasy and sedimentology – an overview.– in: einsele et al. (eds.): cycles and events in stratigraphy, 617–659, springer. vakarcs, g. (1997): sequence stratigraphy of the cenozoic pannonian basins, hungary.– unpubl. phd thesis, rice university, houston, texas, 514 p. vakarcs, g., vail, p.r., tari, g., pogácsás, gy., mattick, r.e. & szabó, a. (1994): third-order middle miocene–early pliocene depositional sequences in the prograding delta complex of the pannonian basin.– tectonophysics, 240, 81–106. vass, d. (1999): numeric age of the sarmatian boundaries (suess 1866).– slovak geol. mag., 5, 227–232. vass, d., repčok, i., balogh, k. & halmai, j. (1987): revised radiometric time-scale for the central paratethyan neogene.– annals of the hungarian geological institute, 70, 423–434, budapest. velić, j. & durn, g. (1993): alternating lacustrine–marsh sedimentation and subareal exposure phases during quaternary: prečko, zagreb, croatia.– geol. croatica, 46/1, 71–90. velić, j. & saftić, b. (1991): subsurface spreading and facies characteristics of middle pleistocene deposits between zaprešić and samobor.– geol. vjesnik, 44, 69–82. velić, j., saftić, b. & malvić, t. (1999): lithologic composition and stratigraphy of quaternary sediments in the area of the “jakuševec” waste depository (zagreb, northern croatia).– geol. croatica, 52/2, 119–130. velić, j., tišljar, j., dragičević, i. & blašković, i. (2000): shoreline cross-bedded biocalcarenites (middle miocene) in the podvrško–šnjegavić area, mt. psunj, and their petroleum significance (požega subdepression – eastern croatia).– geol. croatica, 53/2, 281–293. velić, j., weisser, m., saftić, b., vrbanac, b. & ivković, ž. (2002): petroleum-geological characteristics and exploration level of the three neogene depositional megacycles in the croatian part of the pannonian basin.– nafta, 53/6–7, 239–249, zagreb. vrbanac, b. (2002a): chronohorizons based on resistivity curve variations – upper miocene sediments of the ivanić grad formation in the sava depression, nw croatia.– geol. croatica, 55/1, 11–23. vrbanac, b. (2002b): facies and facies architecture of the ivanić grad formation (upper pannonian) – sava depression, nw croatia.– geol. croatica, 55/1, 57–77. manuscript received april 16, 2003. revised manuscript accepted june 20, 2003. g eol. c roat . 49/2 1325 -326 1 zagreb 1996 1 abstract· note the lower pannonian (s.str.) in the sava river depression a great challenge for more economical oil exploration z agorka bosko v steiner proceedings th e la te ra l ex te n t of the l o we r panno nian w ithi n the sava basin wil l be d iscussed. sed iments of this sub­ age have been mapped and sepa rated on outcrops in tile rim of depress ion and in cores and logs of dri lled deep wells as: the ii hoslratigraphic unit prkosjonllqrioll ; the bios tra ti g raphic uni ts cej lozoii c radix croat ica and e el/ozolle sillzowclla (nubeclila ria) jlollorosica , and the chronostrat igraph ic unit l ower pa fl llon ian sub­ stage. t here arc signifi cant data showing that these un it s may be seri ous ta rge ts for the ex istence of trap ped or bypassed oil and/or gas. sed iment s o f the lower pan­ noni an substage were deposited over a re lati vely shon period from 11 ma till 9.5 ma in a durat ion of 1.5 mil ­ lion years. a sci of pa laeogeographic and biochemica l conditi ons resulted in a deposition of a limestone faci es (of a lgae and of chemi ca l or igin) and a calcareoll s sa nds to ne w ith benthic foram in ife ra , ostracods and molluscs. due to the ir pe trograph ic, pa laeonto log ical and s tn.ui graphi c cha rac tc ri stics these sediments have bee n s tu di ed by num erous auth ors (go rj anov ic­ kramb erger , 189 1; las karev, 1924; 0 2e­ govic, 1944; jenko, 1944; moos, 1944; boskov st ajner & toma sovic, 1967; plet ik apic, 1969; bos ko v stajner & koc hans k y dev ­ id e, 1975; papp, 1985; yanko & larchenkov, 1991 ; s ik ic, 1995 anel ot hers) . the immedi ate base­ ment o f these sedi ments is the lower sannatian clayey depos it. t he o ve rlaying rock is a ma d stone o f the upper pannonian. three orogenic phases a ffected this a rea afte r these sed iment s and ove rlayin g rocks have been depos ited (bos kov st e in er , 1986) : the attican phase ( 10 ma ago), the rhodania n phase (5 ma ago), and the walachian phase (2.5 ma ago) . all these fac to rs, toge ther wit h an adequatc temperature and presence of catalys ts, could have resul ted in the generation of oi l in lower pann onian sediments. oi l may ha ve migrated int o thin sandstone layers, ri ssures formed during men­ tioned oroge ni c phases and, what is mos t import an t, in to the ax ial c res ts o r brach i antic line (bos ko v ivlasarykova 24, zagreb, croalia. stajn er, 1961 ; britvic et 'ii. , 1989). longi tudinal and tran sve rse regiona l fa ult s cou ld have effected the decay of once ex isting reservoirs, as seen [or examp le by the presence of high dens ity and oxid ised o il in out­ crops of the northern rim of the sava bas in, in paklcni ­ ca (bos kov stelner & steiner, 1995) oil product ion ex ists from dee p we lls dri ll ed al more locali ties from these sediments in the sava bas in (bos kov st ajner & marinovic, 197 1). 111 these sediments o il was found: a) in the calcareous component in fi ssures of more generations; b) in sand lcnses o f smal l dimensions; c) in sand layers of large dimens ions; d) in rock mirrors; e) in fractures and fissures a long fau lts; t) in cres ts of brachi anticli ne axes. i have chosen these sed iments to propose the recov­ e ry of the by-passed and captured oil by horizontal o r extended-reach wells, s ince it. may be re lati ve ly easy to do the preparation for various reasons: basic geological maps show ing outc rops o r these sediments a re ava il­ able; outcrops wi th oil in fi ssures, in lenses and in mem­ bers are di sposab le; outc rops cont a ini ng o il are di spos­ abl e in the ea rli er subsurface mining works; the re are corcs fro m dee p we ll s dr illed on seve ral localiti es through these sediments; 2 d seismic sec ti ons are ava il­ able and may be re interpreted ; we ll logs and dip mea­ surements of deep well s are avai lab le; and struc tu ral maps of bedding and th ickness of the prkos formatio n are available . a re inte rpre ted map o f o il and gas satu ration fo re­ cast may be elaborated fro l11 ea rl ier maps wit.h addi tion­ al ana lyses and supplementary 2d and/or 3d sc ism ics. t he potentia l area has to be defined using : corre lat ion of seism ic tim e marke rs; corre lat ion of ciuono­ s tj"al igraphic un its; a s tudy of the gene ra tive po tent ia l (aft er lopati n, waples, barke r and/or othe r me thods); and newcndorp 's method of monte carlo simu lat ion of the oil or gas reservo ir net recent va lue. as to ge t a higher degree of ce rtainty o f the progno­ sis, on each of prospective area a vc rt ica l well may be drill ed fo r checki ng the accuracy of ex isting data and 326 for the mcasurcment of fis sure orientatioll. 'f he es tab­ lished reserves o f the by-passed and captured oi l we may put into production by convent ional and noll-con­ ventional methods (horvat & boskov steiner, 1990). l3y the rat ional teamwork of geologists, reservoir engi neers and dr ill e rs, horizontal drilling of structures containin g rese rvoi rs with the by-passed and/or cap­ tured oil can be programmed and realised (st einer & boskov ste iner, 1994). 'fh cse scd in1cnts, based on their recognised cha rac­ ter ist ics, may aid the reconstruction oj" the sava depres­ sion area as a datum level [or the proressional petrol e­ ll!11 geo logical unde rstanding of the area and for fore­ casting of potent ial places of oil accumulation, and as a datum level ro r the broader geological scienti fie study o f the sava basin. references boskov steiner, z. ( 1986): speeificnosti potene i­ jab ugjjikovodika i pratecih supstanci u panonskoj depres iji. na rt a, 37/7-8, 363-366, zagreb. boskov sterner, z. & steiner, i. ( 1995): geo­ log ica l parti cularities of horizontal we ll s applica­ tion in petroleum engineering. first croa ti an geo­ logica l congress, opatija, proceed ings, l, 113-116, zag reb. boskov stajner, z. ( 1961 ): gcologija brahiantik­ lin~de mramor i3rclo. prinos poznavanju neogcnskih nas laga 11<1 juznom rll bll moslavackc gorc.gco !. vjesnik, 14,97-107, zagreb. boskov st ajner, z. & kocil ansky devide, v. ( 1975 ): prilog poznavanju s trati gra fskog st uba sw dijckl punonskc potoline brakicni srcdnji sar­ mat ako :iec zag reba.nafta , 26/ i 0, 5 12-5 14, zagreb. boskov st ajner , z. & marinovic, dj. ( 197 1): strat ig raphy of oil and gas fields in the te rritory of yugoslavia.-narta, 22/6, 524-532, zagreb. boskov stajner, z. & tomasovi c, t. ( 1967): s[rhtigrafska pripadnost nartnih i plinskih kolek[ora u s r i-irva[skoj, refcrati vi savje[ova nja geologa sfrj, 3, 227-234, skopje. britv ic , b. , dragt\s , m. & skansi , r. ( 1989): piroliticko-vol umet rijski model proracuna genera­ [i vllog potencijala.naft a, 40n -8, 375-39 1, zagreb. geologia cro:nica 49{2 gorjanovic kramberger , d. (189 1): die prae­ pontische bildungen des agramer gebirgcs.verh. r.a., 40, wicn. horvat, k. & boskov steiner z. ( 1990): isku­ stva ist razivanja ugljikovodika od homogcn ih jed­ nostavnih do slozcnih hctcrogcnih lezista. 12. kon­ gres geologa jugoslav ijc, 4, 328-34 1, ohrid. .l en ko, k. (1944): strat igrafski i tcktonski snosaj plio­ cena juznog pobocja pozcskc gore i kasonja brda. ­ vj. rlrv. geol. zavoda, 2-3, 148-159, zagreb. las karev, v. (1924): sur les 12quivalents elu sarma­ tien supericur cn serbie.r(;clicil d. tray . o ilen s a m. 1. cvijic, 73-86, beograd. moos, a. (1 944): neuc f-ulld c von limnaeidcn, ins­ besondere von va lencicnesiiden im panon kroa[ ­ iens.vj. hrv. geol. zavoda, 2-3, 34 1-390, zagreb. ozegovic, f. (1944): prilag gcologij i mladeg te rei­ jara na [emelju podataka iz novijih dubokih busoti­ na .vj. rtrv. geo!. zavoda, 2-3, 39 i -49 j, zagreb. papp, a. (ccl. ) (1985 ): m" pannoni en. chronostratig­ raphy und neostratotypen, mioziin der zcntra len paratethys, vii, akadcmiai kiad6, budapest , 636 p. pletikapic, z. ( 1969): stratigntfija, paleogeografi ja i nanoplinonosnost ivanic grad-rormacije na obodu moslavackog masiva.rud. -geo l. -na f. rakliltet, zagreb, 70 p. sterner, i. & boskov ste iner , z. ( 1994): teh no logija vocloravl1oga buscnja.i3 arbat, zagreb, 170 p. si ki c, k. ( 1995): prika7. geoloske grade medvednice, s trll ktu rni odnos i i tekt ogencza s ireg podrucja medvednice, t rasa br. 2, pos taja 11. gcoloski vodic medvedniec, igt zagreb and in!\-naftaplin , 7-40,6 1-66, zagreb. yanko, v. & larcttenkov, e. ( 1991 ): the influ­ ence of the geodynami c and il ydrologic regime on the origin and evolutioll of the foram inifera in the paralet hys during the end or middl e mi ocene and sa rm at ian. geodynami c evolution o f lhe pal1j101l ­ ian bas in , sanu. vol. lxii , 111 -120, l3eograd. orescanin et al.indd 1. introduction during the last decade special research has focused on an assessment of the environmental state of the river danube and its delta (literathy & laszlo, 1995, 1999; winkels et al., 1998; gruiz et al., 1998; ricking & terytze, 1999; gundacker, 2000; dinescu & duliu, 2001; secrieru & secrieru, 2002; wehland et al., 2002; macklin et al., 2003; woitke et al., 2003). such attention on the danube is understandable as it is europe’s second-longest river (after the volga), and receives various pollutants released from 10 countries before it eventually enters the black sea. granulometric and chemical composition of the danube river sediments, batina village, croatia višnja oreščanin1, stipe lulić1, gordana medunić2 and luka mikelić1 to our knowledge, there are no published papers dealing with such environmental problems regarding the croatian stretch of the danube. this paper reports the concentrations of ca, cr, cu, fe, k, mn, ni, pb, rb, sr, ti, v, y, zn and zr determined in three types of recent sediment, taken from the river channel, which are defined as follows: (1) bulk samples collected in august, (2) their grain size fractions, and (3) the size fraction <0.5 mm of samples collected in march, august, september and october to determine temporal patterns of variables. these three types of sedimentary material were subsequently assayed for cr, cu, fe, mn, ni, pb and zn levels in an exchangeable phase. from the various sediment constituents which are free of human interference (e.g., al, sc, rb, li, toc, ti), rubidium was chosen here as a normalizing factor, used to locate an area of anthropogenic pollution (hanson et al., 1993; daskalakis & o’connor, 1995; prohić et al., 1995). seasonal variations of selected variables are presented graphically. 2. study area the danube river sediments, at the city of mohács on the hungarian stretch of the river and at the village of batina on the croatian stretch of the river, are collected in turn, four times a year for the purpose of radiometric measurements. it is a part of the danube river water management under the boundary waters treaty between croatia and hungary. the village of batina, situated 5 km away from the croatian–hungarian border (fig. 1), also represented one of sampling stations along the river danube under the joint danube survey (croatia, river–km 1424) belonging to geo-morphological reach number 5 which was characterized by significant emissions of untreated wastewater in budapest (vogel & pall, 2001; woitke et al., 2003). the river danube forms a 150 km long border between croatia and serbia and monte negro (fig. 1). the holocene deposits are represented by three alluvial terraces ranging from 10–15 metres in thickness and are composed of clayey, silty and sandy sediments (magaš, 1987). the fluviatile history of the terrain dates back to the lower pleistocene, whereas the largest sediment loading in the lower holocene resulted from excessive melting of alpine glaciers due to marked climate change. geologia croatica 58/2 185–194 7 figs. 4 tabs. zagreb 2005 key words: recent river sediments, heavy metals, edxrf, normalization, seasonal variation, river danube, croatia. 1 institute rudjer bošković, laboratory for radioecology, pob 180, bijenička 54, hr-10000 zagreb, croatia; e-mail: vobescan@rudjer.irb.hr 2 faculty of science, institute of mineralogy and petrography, university of zagreb, horvatovac bb, hr-10000 zagreb, croatia. abstract the size-fractionated recent sediments of the danube river, from batina, were assayed for the total concentrations of 15 elements: ca, cr, cu, fe, k, mn, ni, pb, rb, sr, ti, v, y, zn and zr. it was found that trace metals increased with decreasing particle size, whereas the highest levels of organic matter from loss on ignition tests were found in the 0.5–1 mm fraction. the exchangeable phase accounted for a very minor proportion of the total heavy metal concentrations. seasonal patterns of exchangeable pb, zn, cu, ni, mn and fe were more irregular than those of total metal levels, both generally reflecting a decrease in concentrations during spring. rubidium normalization of the pb, cu, zn, ni, cr, mn and fe concentrations was applied on the <0.063 mm fraction. a certain amount of the cu and ni concentrations may be related to anthropogenic rather than natural processes upstream of the study area and around one of the localities. 186 geologia croatica 58/2 3. materials and methods sediment samples were collected at four locations upstream and downstream of a bridge crossing the river danube in the village of batina (fig. 1). sampling was carried out in march, august, september and october of 2002. at each location in the river channel, a composite sample of up to 1 kg was collected from at least three points within a perimeter of 50 m. the samples were taken manually with a plastic scraper and spatula, which were washed and cleaned with stream water between samples. sediments were put into plastic boxes and transported to the laboratory. each august sample was mixed thoroughly and approximately 100 g of subsample was dried at 105°c in a drying oven to eliminate any water, disaggregated in an agate mortar and prepared for determination of the total elemental composition (ca, cr, cu, fe, k, mn, ni, pb, rb, sr, ti, v, y, zn and zr), loss on ignition (loi), and cr, cu, fe, mn, ni, pb and zn levels in exchangeable phase. the remainder was wet sieved to four size fractions (<0.063 mm, 0.063–0.250 mm, 0.25–0.5 mm and 0.5–1 mm), each fraction being subsequently dried at 105°c and reweighed. the fractions were assayed by xrf analysis for the total elemental composition as well as for heavy metal levels in an exchangeable phase and subjected to determination by loi. the total elemental composition together with loi, and heavy metal levels in exchangeable phase were determined in the <0.5 mm fraction of march, august, september and october samples. although organic carbon contents are frequently determined by loss on ignition, it is generally held that the results may not be very accurate (tucker, 1988), principally due to the presence of water or constituent ohgroups which are tightly bound in minerals and can be driven off at temperatures higher than 105°c. therefore, loss on ignition determined at 375°c, used as an indicator of organic mater in this investigation, can be considered as an approximation. concentrations of ca, cr, cu, fe, k, mn, ni, pb, rb, sr, ti, v, y, zn and zr in different size fractions as well as in bulk samples were determined using the energy dispersive x-ray fluorescence, edxrf method (oreščanin et al., 2002). approximately 2 g of powdered sample was pressed into a pellet and irradiated for 7000 s. 1 g of powdered sample (dry weight) was subjected to a single step sequential extraction procedure. ammonium acetate/acetic acid (ph 7.0) was employed to liberate exchangeable metals (oreščanin et al., 2003). the extract was diluted to 100 ml with double distilled water and adjusted to ph 3 by the addition of concentrated hno3/nh4oh. after the ph adjustment, samples were precipitated by adding 2 ml of freshly prepared 1% w/v solution of ammonium-pyrrolidinedithiocarbamate (apdc). after the complexation which lasted 20 min, the suspension was filtered through a millipore filter (0.45 µm) and irradiated. all targets were analysed by edxrf. samples were irradiated by x-rays generated from the 109cd annular source. the angle between the sample and the source was 89°. the detection of the characteristic x-ray radiation from the sample was conducted with a si (li) detector (canberra) cooled with liquid nitrogen with the following characteristics: detector size – 30 mm2, si thickness – 3 mm, be window – 25 μm, fwhm for 5.9 kev 55 fe 165 ev. the angle between the sample and the detector was 1° and the distance was 1.5 cm. spectra were collected by genie–2000 software (canberra). collecting time was 10000 s for the thin targets (filters) and 7000 s for the thick targets (pressed pellets). spectral data were analysed by winaxil software (canberra). a calibration file for thin targets was created on the basis of measurement of standard solutions (merck) prepared and analysed in the same way as unknown samples. elemental concentrations in the thick targets were calculated using the “fundamental parameters” method from the winfund package using iaea srm sl–1 and soil 7 as standards. mohács osijek drava croatia serbia & montenegro hungary batina 1 2 3 4 danube 5 km batina danube gajić draž zmajevac river karašica barački dunav fig. 1 geographical location of the study area (framed part) and sampling localities (1, 2, 3, and 4). site 4 marks the downstream direction. 187oreščanin et al.: granulometric and chemical composition of the danube river sediments... 4. results and discussion particle-size analysis shows that all four locations have rather similar granulometric composition (fig. 2) which could be defined as muddy, fine to medium sand. this enables the comparison of elemental concentrations between the locations since the textural characteristics of sediments largely govern storage of sediment-associated heavy metals in river systems (förstner & wittmann, 1979; salomons & förstner, 1984; brook & moore, 1988; graf et al., 1991; macklin, 1996; ladd et al., 1998; oreščanin et al., 2002; walling et al., 2003). it is generally accepted that the silt and clay fractions of sediments have a strong ability to scavenge trace elements, and this is attributed to the large surface area of fine particles as well as to their varied shape and charge (gibbs, 1977; rose et al., 1979; salomons & förstner, 1984; williamson et al., 1994). due to adsorption onto surfaces of particles, the highest concentrations of ca, cr, cu, fe, k, mn, ni, pb, rb, sr, y, zn and zr were found in the finest fraction (<0.063 mm), steadily decreasing towards the coarser fractions (table 1). loss on ignition at 375°c, as an approximate indicator of organic mater (om), was also grain size dependent. the coarse sand fraction (0.5–1 mm) of locations 2, 3 and 4 contained the greatest amount of om, with values declining to the <0.063 mm fraction, whereas the opposite trend was found for location 1 (table 1). although total pb, rb, sr, ca, mn, fe, cu and zn concentrations are positively correlated with om, chemical characterization of each size fraction suggests that organic matter does not exert overall control over the levels of the analysed elements compared to the granulometric characteristics of sediments (table 1). the exchangeable phase is generally assumed to be the most mobile fraction of elements which is introduced by anthropogenic activities and bound to sediment in the adsorbed form (gibbs, 1977; förstner & wittmann, 1979; salomons & förstner, 1984; chao, 1984; brook & moore, 1988; hall, 1998). this phase, as a chemically active and biologically available form, does not pose a threat for the investigated sediments since it forms a negligible proportion of sediment associated metals the patterns of which are almost identical at all four locations (fig. 3). it can be seen that only copper exhibited slightly higher levels in an exchangeable phase compared to pb, zn and ni at localities 2, 3 and 4. moreover, exchangeable cu values were found to be considerably enhanced in the grain size fractions <0.063 mm and 0.5–1 mm (table 2), thereby positively correlating with organic matter content which showed a marked rise in these two fractions (table 1). this feature is probably due to the fact that cu forms stable organo–copper complexes (salomons & förstner, 1984; adriano, 1986). it is also in accordance with findings of hall (1998) about non-specific adsorption due to the negative charges on humus polymers and specific adsorption through surface chelation of metals with various functional groups on organic substances. seasonal variation in the elemental content of sediments was determined by analysing the <0.5 mm grain size fraction. this particle size is otherwise routinely used for radiometric measurements, while its chemical composition is first documented in this research. results for march, august, september and october are presented in table 3, and selected variables are graphically presented in fig. 4. from this, it can be inferred that variation in concentrations significantly depends on seasonal >1 mm 0.5-1 mm 0.25-0.5 mm 0.063-0.25 mm <0.063 mm1 2 3 4 sampling localities 0 20 40 60 80 100 w t% fig. 2 grain size distribution of sediment samples collected in august at the four sampling localities (<0.063 mm – clay and silt (mud); 0.063–0.25 mm – very fine and fine sand; 0.25–0.5 mm – medium sand; 0.5–1 mm – coarse sand; >1 mm – very coarse sand). 188 geologia croatica 58/2 1 2 3 4 a b c d t a b c d t a b c d t a b c d t p b (p pm ) 40 14 15 10 22 47 14 15 10 30 45 16 29 19 31 41 16 15 10 27 r b (p pm ) 96 .0 46 .1 54 .0 27 .4 61 .7 10 2. 0 46 .2 47 .5 24 .3 71 99 .6 46 .6 48 .0 26 .2 76 .8 92 .0 50 .9 53 .9 20 .1 71 .7 s r ( pp m ) 25 7 16 9 10 6 60 18 3 22 2 16 8 90 49 19 3 25 3 16 1 92 49 19 9 23 5 17 2 91 44 19 6 y (p pm ) 58 41 17 13 41 56 32 13 12 42 57 31 14 11 42 .0 55 43 17 12 46 .3 zr (p pm ) 34 7 27 9 80 69 22 6 28 6 17 5 53 47 22 7 35 2 20 8 60 50 27 1 32 2 28 4 59 41 35 3 k (% ) 2. 11 1. 02 1. 27 0. 70 1. 35 1. 90 1. 11 1. 19 0. 68 1. 6 2. 00 1. 20 1. 12 0. 88 1. 69 1. 90 1. 19 1. 35 0. 68 1. 72 c a (% ) 9. 9 6. 2 2. 6 1. 8 7. 0 7. 4 6. 4 2. 0 1. 8 7. 5 9. 3 6. 0 2. 1 1. 5 7. 8 8. 7 6. 1 1. 9 1. 7 7. 6 ti (% ) 0. 31 8 0. 33 0 0. 11 3 0. 09 6 0. 28 3 0. 34 0 0. 25 2 0. 06 6 0. 03 9 0. 30 0. 33 3 0. 31 2 0. 08 9 0. 05 7 0. 28 9 0. 32 0. 35 7 0. 09 9 0. 03 1 0. 29 9 v (p pm ) 70 70 30 40 60 80 36 21 27 80 80 70 60 34 50 80 60 50 27 50 c r ( pp m ) 90 80 52 27 70 90 50 43 26 70 80 10 0 60 37 66 10 0 61 60 26 63 m n (p pm ) 63 0 41 0 15 3 13 4 43 0 65 0 32 5 88 67 52 0 67 4 32 0 13 0 89 53 3 56 0 38 1 15 0 67 51 8 fe (% ) 2. 54 1 1. 20 1 0. 77 0 0. 60 1 1. 58 2 2. 80 8 1. 08 2 0. 54 59 0 .4 97 1. 90 7 2. 73 9 1. 09 6 0. 68 6 0. 57 4 2. 04 5 2. 43 9 1. 31 1 0. 90 6 0. 49 7 1. 96 8 n i ( pp m ) 28 24 23 24 24 50 32 28 30 38 40 27 28 29 30 30 26 27 27 29 c u (p pm ) 15 0 20 19 14 26 77 19 17 13 26 68 18 17 13 29 60 20 16 12 26 zn (p pm ) 28 6 55 56 54 11 0 30 2 54 43 .0 40 15 6 29 9 58 55 50 17 2 26 1 68 69 57 14 6 lo i a t 3 75 °c (% ) 4. 47 0. 3 0. 39 3. 38 1. 71 5. 49 0. 37 0. 4 13 .4 4 2. 64 5. 79 0. 45 1 0. 50 12 .3 2 2. 84 5. 69 0. 44 0. 72 15 .9 9 2. 33 1 2 3 4 a b c d t a b c d t a b c d t a b c d t c r 0. 9 0. 6 0. 9 0. 6 0. 7 1. 0 0. 9 0. 9 1. 0 1. 0 0. 9 1. 2 0. 6 0. 9 0. 8 0. 9 0. 8 0. 6 0. 8 0. 8 m n 0. 9 1. 0 2. 5 0. 8 0. 9 1. 1 1. 5 3. 2 1. 2 3. 0 1. 0 1. 9 1. 3 0. 9 1. 5 1. 2 2. 0 3. 2 1. 3 1. 9 fe 3. 3 3. 9 8. 5 9. 1 3. 3 4. 4 4. 9 12 .3 4. 2 10 .7 3. 0 6. 8 4. 7 3. 3 5. 7 6. 2 8. 7 14 .1 5. 9 8. 5 n i 0. 8 0. 5 0. 5 0. 8 0. 5 0. 7 0. 6 0. 3 0. 7 0. 4 0. 6 0. 4 0. 3 0. 6 0. 8 0. 5 0. 3 0. 2 0. 5 0. 8 c u 13 .1 1. 5 1. 1 1. 1 1. 2 3. 4 1. 3 1. 0 2. 9 1. 4 3. 9 1. 1 0. 9 3. 4 1. 5 3. 7 1. 0 0. 9 3. 5 1. 8 zn 2. 8 6. 1 4. 4 2. 3 5. 6 6. 3 1. 7 2. 4 5. 8 3. 8 1. 1 4. 0 1. 9 1. 0 6. 0 0. 5 5. 1 2. 8 1. 2 3. 2 p b 1. 3 1. 3 0. 9 1. 1 1. 1 1. 4 1. 3 1. 1 1. 3 0. 9 1. 3 1. 0 1. 2 1. 1 1. 4 1. 4 1. 2 0. 9 1. 3 1. 2 ta bl e 1 l os s on ig ni tio n (l o i, in % ) an d to ta l-m et al a na ly si s of s iz efra ct io na te d se di m en ts c ol le ct ed in a ug us t ( nu m be rs 1 –4 m ar k sa m pl in g si te s) . c ap ita l l et te rs in di ca te s iz e fra ct io ns a s fo llo w s: a : < 0. 06 3 m m , b : 0 .0 63 –0 .2 5 m m , c : 0 .2 5– 0. 5 m m , d : 0 .5 –1 m m , t : b ul k se di m en t. ta bl e 2 e xc ha ng ea bl e ph as e (in p pm ) of s iz efra ct io na te d se di m en ts c ol le ct ed in a ug us t ( nu m be rs 1 –4 m ar k sa m pl in g si te s) . c ap ita l l et te rs in di ca te s iz e fra ct io ns a s fo llo w s: a : < 0. 06 3 m m , b : 0 .0 63 –0 .2 5 m m , c : 0 .2 5– 0. 5 m m , d : 0 .5 –1 m m , t : b ul k se di m en t. 189oreščanin et al.: granulometric and chemical composition of the danube river sediments... dilution with snow melt. therefore concentrations are low in spring (march) and they gradually rise in summer and early autumn (august, september). while the majority of variables show concordant patterns for march, august and september, this cannot be said for october (fig. 4). patterns obtained for march generally decrease towards location 3 and increase slightly again at location 4, whereas august and september are characterized by concentration peaks at locality 2 and a gradual decrease in the downstream direction. patterns observed for october show that all the presented variables (fig. 4), except pb, increase in a downstream direction, which is unexpected because there are no tributaries of the danube which could feed the lower stretch of the study area (fig. 1). table 4 shows the temporal variability of heavy metals in exchangeable phase within the <0.5 mm grain size fraction. figure 5 demonstrates that the concentrations of all the analysed variables decrease during spring snowmelt due to dilution. element patterns for march are mutually quite concordant showing an enhanced peak at locality 2, which has already been observed for august and september on fig. 4, and a steep decline in a downstream direction. the other three months are characterized by generally higher concentrations of fe, zn, mn and pb, whereas cu and ni values are either lower or similar to those found for march (fig. 5). when considering mutual comparison of the summer and autumnal element patterns separately for each month (fig. 5), it is obvious that they are rather irregular which is in contrast to the patterns depicted on fig. 4. only the patterns for fe and mn are fairly similar when observing individual months (fig. 5). although the sampling sites were all rather similar in granulometric composition, fe and zn vary by a wide range during summer and autumn, which is in fig. 3 exchangeable phase (ads) vs. total metal levels in august sediment samples. the remainder represents other phases that were not analysed. fig. 4 seasonal variation in the elemental content of the <0.5 mm grain size fraction. 190 geologia croatica 58/2 contrast to their much more uniform spring patterns. this striking feature has yet to be clarified and requires future work. generally, it can be said that there is no clear trend of exchangeable metal concentrations in a m ar ch a ug us t se pt em be r o ct ob er 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 c r 1. 7 1. 0 1. 2 1. 0 0. 8 0. 8 1. 0 0. 8 0. 8 1. 1 1. 0 0. 7 0. 8 0. 8 1. 0 0. 8 m n 0. 8 0. 7 0. 6 0. 4 1. 0 1. 4 1. 3 2. 0 1. 0 1. 2 1. 1 0. 7 2. 4 2. 3 0. 8 0. 9 fe 2. 1 3. 8 2. 5 1. 6 2. 5 3. 7 3. 2 6. 9 2. 8 3. 3 4. 2 2. 9 8. 2 7. 7 2. 8 3. 6 n i 0. 3 0. 8 0. 4 0. 2 0. 6 0. 6 0. 4 0. 5 0. 3 0. 8 0. 8 0. 3 0. 7 0. 6 0. 8 0. 6 c u 1. 1 3. 6 1. 6 1. 0 1. 2 1. 9 1. 7 1. 4 1. 0 1. 6 1. 1 0. 9 1. 0 1. 2 1. 4 1. 6 zn 1. 2 4. 3 1. 5 0. 3 4. 9 2. 7 2. 9 1. 6 1. 1 7. 2 1. 7 1. 4 3. 1 1. 5 4. 9 1. 0 p b 0. 2 0. 2 0. 2 0. 2 1. 3 1. 4 1. 1 1. 1 1. 1 1. 3 1. 5 0. 9 1. 3 1. 1 1. 1 0. 9 m ar ch a ug us t se pt em be r o ct ob er 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 p b (p pm ) 17 14 9 12 21 29 19 19 41 54 28 28 41 54 28 28 r b (p pm ) 65 .0 53 .5 34 .6 52 .8 55 .5 68 .7 53 .8 47 .2 95 10 2 77 .0 65 .0 51 .7 46 .8 70 70 .0 s r ( pp m ) 16 4 13 1 10 5 14 6 19 2 20 3 18 0 14 2 21 0 19 5 20 3 18 6 18 5 17 7 18 5 24 2 y (p pm ) 39 35 24 32 46 43 37 40 53 57 49 43 53 51 56 46 zr (p pm ) 18 4 14 4 13 0 15 4 27 7 24 1 26 5 30 2 23 1 21 6 25 8 24 8 34 8 27 9 40 7 26 1 k (% ) 1. 40 1. 11 0. 78 1. 17 1. 28 1. 63 1. 33 1. 50 2. 20 2. 20 1. 70 1. 46 1. 21 1. 19 1. 70 1. 52 c a (% ) 7. 1 4. 9 4. 1 5. 9 8. 2 8. 7 7. 6 7. 2 6. 2 5. 3 6. 8 6. 6 7. 9 8. 2 6. 3 11 .0 ti (% ) 0. 22 2 0. 15 9 0. 11 4 0. 19 3 0. 34 0 0. 26 6 0. 30 9 0. 29 0 0. 31 6 0. 35 0 0. 30 2 0. 28 0 0. 42 0 0. 45 0 0. 43 0 0. 24 6 v (p pm ) 60 60 50 50 90 70 50 80 14 0 90 90 70 90 90 11 0 60 c r ( pp m ) 45 40 42 51 50 80 61 60 60 80 80 70 70 80 10 0 80 m n (p pm ) 38 0 31 0 19 0 28 0 49 0 55 3 45 7 43 0 66 0 71 0 52 0 44 0 54 0 56 0 80 0 73 0 fe (% ) 1. 52 8 1. 15 9 0. 68 8 1. 10 4 1. 61 1 1. 89 0 1. 50 6 1. 52 0 2. 52 8 2. 71 7 1. 99 3 1. 67 3 1. 70 0 1. 64 4 2. 34 7 1. 95 1 n i ( pp m ) 50 50 35 40 24 36 30 27 50 50 28 30 28 30 28 43 c u (p pm ) 24 16 11 17 24 28 23 21 35 40 31 26 18 29 31 34 zn (p pm ) 97 73 39 59 99 14 7 90 10 1 21 4 29 1 13 5 11 4 82 89 24 4 20 5 lo i a t 3 75 °c (% ) 1. 29 0. 96 0. 49 0. 57 1. 32 1. 95 2. 18 3. 24 2. 96 3. 82 1. 99 1. 38 0. 89 0. 95 2. 69 2. 70 ta bl e 3 s ea so na l v ar ia tio n in e le m en ta l c on te nt o f t he g ra in s iz e fra ct io n <0 .5 m m . n um be rs 1 –4 m ar k sa m pl in g si te s. ta bl e 4 s ea so na l v a downstream direction during the summer and autumnal periods (fig. 5). in order to estimate the degree to which a sediment had been subjected to possible heavy metal pol191oreščanin et al.: granulometric and chemical composition of the danube river sediments... lution from the river water, it was necessary to carry out normalization by calculating the ratio of measured concentrations of selected pollutants to the contents of conservative elements the concentrations of which are unaffected by human activity (salomons & förstner, 1984; hanson et al., 1993; daskalakis & o’connor, 1995; prohić et al., 1995; oreščanin et al., 2001). therefore pb, cu, zn, cr, mn, fe and ni concentrations in the fraction <0.063 mm (table 1) have been plotted after normalization to rb. the results in fig. 6 show highly elevated levels of cu and ni at locations 1 and 2, respectively, and a slightly increased level of cr at location 4. because positive deviations of the ratio normally increase as concentrations of normalizing factors decrease, it is suggested that high concentration ratios should not be explained in the pollution context without examination of the actual numbers that comprise the ratio (daskalakis & o’connor, 1995). from an inspection of fig. 7 it is evident that presumed pollution by cu and cr at fig. 5 seasonal variation in the elemental content of exchangeable phases of the <0.5 mm grain size fraction. fig. 6 heavy metal levels after normalization on rb. 192 geologia croatica 58/2 the localities 1 and 4, respectively, is arguable since they are not correlated with rb. on the contrary, a positive excursion of the ni/rb ratio at location 2 (fig. 6) appears to be explained by a factor (anthropogenic?) other than natural processes, according to covariation of ni with rb (fig. 7). it was noted above that the village of batina, under the auspices of the joint danube survey (croatia, river–km 1424), belonged to geomorphological reach number 5 which was characterized by significant emissions of untreated wastewater in budapest (vogel & pall, 2001; woitke et al., 2003). this study suggests that these wastewaters presumably have not contributed to heavy metals incorporated in studied sediments to any extent, based on a comparison of the total pb, cu, zn, cr, mn, fe and ni concentrations (table 1) with the average shale and soil composition (adriano, 1986; thornton, 1995). future work should target the importance of the organic and carbonate fractions in acting as a reservoir for holding heavy metals, cu and ni in particular, as well as detailed mineralogical analysis of sediments. 5. conclusions recent channel sediments of the danube river in the village of batina are mainly composed of muddy, fine to medium sand. it was found that the greatest proportion of the total heavy metal load is contained in the clay and silt fraction, and therefore sediment metal transport appears to be governed primarily by sorption–desorption processes associated with fine-grained particles. generally, no correlation was found between trace metals and loss on ignition, which served as an indicator of organic matter content, but this subject has yet to be firmly established in future work. sequential extraction of bulk sediment samples showed that negligible concentrations of heavy metals were present in exchangeable phases. among the exchangeable metals analysed, only cu correlated with loss on ignition, since both were enriched in the size fractions <0.063 and 0.5–1 mm. seasonal variation in the elemental content of the <0.5 mm grain size fraction and its exchangeable phase was found to be considerably dependent on seasonal dilution with snow melt. a number of analysed elements decreased in concentration through the spring period whereas their levels increased during the summer and autumnal periods. normalization based on rb in the <0.063 mm size fraction showed that cu and ni exhibited only light enrichments at locations 1 and 2, respectively. a comparison of the total pb, cu, zn, cr, mn, fe and ni concentrations with the average shale and soil composition suggests that the analysed metals represent mostly natural levels in the investigated sediments. 6. references adriano, d.c. (1986): trace elements in the terrestrial environment.– springer verlag, new york, berlin, heidelberg, tokyo, 533 p. brook, e.j. & moore, j.n. (1988): particle-size and chemical control of as, cd, cu, fe, mn, ni, pb, and zn in bed sediment from the clark fork river, montana (u.s.a.).– sci. tot. environ., 76, 247–266. fig. 7 heavy metal and rb concentrations in the <0.063 mm grain size fraction. 193oreščanin et al.: granulometric and chemical composition of the danube river sediments... chao, t.t. (1984): use of partial dissolution techniques in geochemical exploration.– j. geochem. explor., 20, 101– 135. daskalakis, k.d. & o’connor, t.p. (1995): normalization and elemental sediment contamination in the coastal united states.– environ. sci. technol., 29, 470–477. dinescu, l.c. & duliu, o.g. (2001): heavy metal pollution of some danube delta lacustrine sediments studied by neutron activation analysis.– appl. radiat. isotopes, 54, 853–859. förstner, u. & wittmann, g.t.w. (1979): metal pollution in the aquatic environment.– springer verlag, berlin, heidelberg, new york, 486 p. gibbs, r.j. (1977): transport phases of transition metals in the amazon and yukon rivers.– geol. soc. am. bull., 88, 829–843. graf, w.l., clark, s.l., kammerer, m.t., lehman, t., randall, k. & schroeder, r. (1991): geomorphology of heavy metals in the sediments of queen creek, arizona, usa.– catena, 18, 567–582. gruiz, k., muranyi, a., molnar, m. & horvath, b. (1998): risk assessment of heavy metal contamination in danube sediments from hungary.– water sci. technol., 37, 273–281. gundacker, c. (2000): comparison of heavy metal bioaccumulation in freshwater molluscs of urban river habitats in vienna.– environ. pollut., 110, 61–71. hall, g.e.m. (1998): analytical perspective on trace element species of interest in exploration.– j. geochem. explor., 61, 1–19. hanson, p.j., evans, d.w., colby, d.r. & zdanowicz, v.s. (1993): assessment of elemental contamination in estuarine and coastal environments based on geochemical and statistical modeling of sediments.– mar. environ. res., 36/4, 237–266. ladd, s.c., marcus, w.a. & cherry, s. (1998): differences in trace metal concentrations among fluvial morphologic units and implications for sampling.– environ. geol., 36, 259–270. literathy, p. & laszlo, f. (1995): harmonisation of micropollutant monitoring in a large international river: danube.– water sci. technol., 32, 125–137. literathy, p. & laszlo, f. (1999): micropollutants in the danube river basin.– water sci. technol., 40, 17–26. macklin, m.g. (1996): fluxes and storage of sedimentassociated heavy metals in floodplain systems: assessment and river basin management issues at a time of rapid environmental change.– in: anderson, m.g., walling, d.e. & bates, p.d. (eds.): floodplain processes. wiley, chichester, 441–460. macklin, m.g., brewer, p.a., balteanu, d., coulthard, t.j., driga, b., howard, a.j. & zaharia, s. (2003): the long term fate and environmental significance of contaminant metals released by the january and march 2000 mining tailings dam failures in maramureş county, upper tisa basin, romania.– appl. geochem., 18, 241–257. magaš, n. (1987): osnovna geološka karta sfrj 1:100000. tumač za list osijek l34–86 (basic geological map of sfry, 1:100,000. geology of osijek sheet).– inst. geol. istraž. zagreb (1967), sav. geol. zavod, beograd, 54 p. oreščanin, v., nađ, k., valković, v., mikulić, n. & meštrović, o. (2001): red mud and waste base: raw materials for coagulant production.– j. trace microprobe tech., 19/3, 419–428. oreščanin, v., mikulić, n., obhođaš, j., nađ, k. & valković, v. (2002): distribution of trace elements in the coastal sea sediments: punat bay in the northern adriatic.– j. trace microprobe tech., 20/2, 247–260. oreščanin, v., katunar, a., kutle, a. & valković, v. (2003): heavy metals in soil, grape and wine.– j. trace microprobe tech., 21/1, 171–180. prohić, e., miko, s. & peh, z. (1995): normalization and trace element contamination of soils in a karstic polje – an example from the sinjsko polje, croatia. – geol. croat., 48/1, 67–86. ricking, m. & terytze, k. (1999): trace metals and organic compounds in sediment samples from the river danube in russe and lake srebarna (bulgaria).– environ. geol., 37, 40–46. rose, a.w., hawkes, h.e. & webb, j.s. (1979): geochemistry in mineral exploration.– academic press, london, new york, toronto, sydney, san francisco, 581 p. salomons, w. & förstner, u. (1984): metals in the hydrocycle.– springer-verlag, berlin, heidelberg, new york, 349 p. secrieru, d. & secrieru, a. (2002): heavy metal enrichment of man-made origin of superficial sediment on the continental shelf of the north-western black sea.– estuar. coast. shelf sci., 54, 513–526. thornton, i. (1995): metals in the global environment: facts and misconceptions.– the international council on metals and the environment, ottawa, 103 p. tucker, m. (1988): techniques in sedimentology.– blackwell science, cambridge, 394 p. vogel, b. & pall, k. (2001): nine geo-morphological danube reaches under consideration of anthropogenic impacts.– jds report, icpdr permanent secretariat, vienna international centre, d0412, 378 p. walling, d.e., owens, p.n., carter, j., leeks, g.j.l., lewis, s., meharg, a.a. & wright, j. (2003): storage of sediment-associated nutrients and contaminants in river channel and floodplain systems.– appl. geochem., 18, 195–220. wehland, f., panaiotu, c., appel, e., hoffmann, v., jordanova, d., jordanova, n. & denut, i. (2002): the dam breakage of baia mare – a pilot study of magnetic screening.– phys. chem. earth, 27, 1371–1376. williamson, r.b., hume, t.m. & molkrijnen, j.a. (1994): comparison of the early diagenetic environment in intertidal sands and muds of the manukau harbor, new zealand.– environ. geol., 24/4, 254–266. winkels, h.j., kroonenberg, s.b., lychagin, m.y., marin, g., rusakov, g.v. & kasimov, n.s. (1998): geochronology of priority pollutants in sedimentation zones of the volga and danube delta in comparison with the rhine delta.– appl. geochem., 13/5, 581–591. 194 geologia croatica 58/2 woitke, p., wellmitz, j., helm, d., kube, p., lepom, p. & litheraty, p. (2003): analysis and assessment of heavy metal pollution in suspended solids and sediments of the river danube.– chemosphere, 51, 633–642. manuscript received december 7, 2004. revised manuscript accepted november 11, 2005. day.indd 149 �ab stra ct karst landscapes in the caribbean cover nearly 130,000km2, more than half the total land area of the region. approximately 90% of the karst is on the greater antilles, with other signifi cant areas in the bahamas, anguilla, antigua, the cayman islands, the virgin islands, guadeloupe, barbados, trinidad and tobago, and the netherlands antilles. there is considerable heterogeneity, but the caribbean contains many “classic” karst landscapes, including cockpits, towers, dry valleys, dolines (sinkholes), blue holes and caves. the karst has played an important role in caribbean history, as a focus of resistance to colonial power, and as a basis for subsistence agriculture following emancipation and independence, increasingly incorporating commercial agriculture, urbanization and industrial activities, and tourism. karst landscape provides a critical physical backdrop for many of the caribbean’s environmental, agricultural, economic and cultural issues, and its sustainability is critical to regional wellbeing. the caribbean karstlands are challenging to human habitation, since they possess a broad array of natural hazards, such as drought and fl ooding, but they are also inherently fragile, at risk of degradation and vulnerable to environmental change. despite this vulnerability to environmental change, under rational management regimes there is no inherent reason why human use should not be sustainable in the long term. human impacts, however, have been longterm and severe, particularly through destruction of natural vegetation, contamination of water supplies, urbanization and quarrying. the caribbean karst continues to play important roles locally, nationally and regionally in water supply, mining and quarrying, agriculture, tourism and conservation, all of which represent specifi c and collective challenges to sustainability of the karst environment. additionally, sustainability is threatened by the consequences of anthropogenic climatic change, which is predicted to lead to increasing air and water temperatures, rising sea levels and changing weather patterns, including decreasing precipitation totals, and the increasing frequency of extreme events, such as droughts and hurricanes, the effects of all of which will be magnifi ed in the karst, particularly with respect to karst hydrology. disruption of the karst hydrological cycle may lead to increasing aridity and desertifi cation, with concomitant impacts on ecology and potential land use. increasing population and economic development will further exacerbate human impacts on the karst landscapes. climate change and other human impacts will increasingly threaten already at-risk and vulnerable ecosystems and human communities, necessitating integration of climate change parameters and the adoption of appropriate risk management measures. the severity of these impacts may be reduced by appropriate land management and land use planning, which are necessary ingredients for long-term sustainability. keywords: caribbean, karst, sustainability, management challenges to sustainability in the caribbean karst � mick day department of geography, university of wisconsin-milwaukee, milwaukee, wisconsin 53201, usa; (mickday@uwm.edu) doi: 104154/gc.2010.12 geologia croatica 63/2 149–154 1 fig. zagreb 2010 geologia croaticageologia croatica geologia croatica 63/2geologia croatica 150 sustainable in the long term under rational management regimes that recognize and encourage appropriate activities whilst restricting those that are deleterious. 2. caribbean karst caribbean limestones range from holocene to jurassic in age (0–200myrs bp). there is a wide range of karst landscapes including dry valleys, dolines (sinkholes), cockpits, residual towers, and extensive cave systems. the karst has been and still is infl uenced by tectonic, eustatic, and climatic changes (day, 1993). the largest karst areas are on the greater antilles (cuba, hispaniola, jamaica, and puerto rico) with a total karst area of approximately 115,000 sq. km (fig. 1). the islands of the bahamas, the lesser antilles, trinidad, tobago, and the netherlands antilles contain an additional 15,000 km2 of karst (day, 1993, 2009). karst topography is variable, although including three distinct styles: doline, cockpit, and tower (day, 1993). doline karst occurs throughout the caribbean whereas cockpit and tower karst occur particularly in the greater antilles (cuba, hispaniola, puerto rico and jamaica). caves are numerous. the karst is heterogeneous with respect to geologic and geomorphic factors, and climate, soils and biota also vary, producing a wide range of specifi c karst environments. karst elevations range from sea level up to 3000m including mountains and plains. some karsts are autogenic, others much infl uenced by allogenic inputs. climate varies considerably, fi gu re 1: major locations of caribbean karst. 1. introduction the caribbean, defi ned broadly as the islands of the greater and lesser antilles, the bahamas, trinidad, tobago, and the netherlands antilles, broadly corresponding to the west indies (watts, 1987), is one of the premier karst regions in the world, with a limestone area of nearly 130,000km2, more than half the total land area of the region (day, 1993). the karst challenges sustained human activities because it possesses a broad array of natural hazards and is inherently fragile and vulnerable to environmental change (day, 1993, in press a). the karst is particularly vulnerable because of its unique hydrology, with sporadic surface drainage, limited surface water storage and rapid subterranean fl ow. karst landscape ecology is adapted to these hydrologic constraints, the parameters of which can be altered radically by anthropogenic environmental change, which threatens sustainability. the iucn world commission on protected areas (wcpa) recognizes karst landscapes, including the caribbean, as being at risk of degradation and warranting protection (watson et al., 1997). protection and conservation are critical in the caribbean, and they are central to a consideration of karst sustainability. this paper considers sustainability of the caribbean karst in relation to past, present and future environmental conditions, particularly those arising from human activities and anthropogenic environmental change (day, 1993; day & chenoweth, 2009). although impacts have already been severe, and future change threatens to be more so, there is no inherent reason why human use should not be day: challenges to sustainability in the caribbean karst geologia croatica 151 rapid surface failure is not common within the caribbean karst, but both ground surface collapse and subsidence represent an increasing threat to developing infrastructure, such as highways and public service facilities, plus a minor hazard to rural dwellings and livestock. slope failure also poses a minor to moderate hazard to buildings, roads and other structures, although one that is rarely recognized. 4. human impacts on the karst human impacts on the caribbean karst have been long-term and severe (day, 1993), in particular through forest clearing, species introduction, agriculture, utilization of water resources, urbanization and industrial activities, including mining. disturbance extends back to pre-colonial times. with a land area of 233,927 km2 (watts, 1987) and a population approaching 40 million people (unep, 2005), pressures on the caribbean karst are already severe. future prospects threaten further exacerbation, through clearing of remaining natural vegetation, species extinction or introduction, expanding agriculture, increasing utilization and contamination of water resources, tourism, urbanization and industrial activities, including quarrying and mining. human impact on the karst may be schematized by reference to a broad, landscape-wide impact-process-consequence model involving human activity, landscape process change and response, and problems for human occupancy and activity. this can be illustrated by reference to the karst hydrologic system, in which forest clearance, agriculture, groundwater abstraction and modifi cation of surface drainage courses has resulted in increased runoff, decreased infi ltration, increased surface sediment transport, and decreased spring discharge. this has impacted sustainability through increased fl ood susceptibility, desiccation of springs and accelerated soil erosion (day, 1993). forest clearance and agriculture have had profound effects on the caribbean karst, and agriculture remains the dominant regional karst land use. although agricultural activities are increasing steadily, they are potentially sustainable in the long-term if subject to rigorous control over soil erosion, water use and contamination and maintenance of protected areas. small-scale agriculture is most suited to much of the caribbean karst, although larger-scale operations are locally feasible if tied to stringent conservation measures. limestone quarrying has had pronounced impacts on the caribbean karst, most signifi cantly for cement production. annual production of limestone and cement are each about 10m mt (day & chenoweth, 2009). there is also a limited amount of marble, gypsum and aragonite mining, plus some small-scale mining of phosphate rock and of bat guano from caves. petroleum reserves are associated with karst in cuba, trinidad, aruba and barbados. commercial bauxite production began in the caribbean in the1950s, and jamaica is the world’s third largest bauxite producer. about 100,000 ha of northern jamaican karst, particularly in the dry harbour mountains, have been exploited for bauxite and alumina by surface mining, with similar areas affected in the southwith mean annual precipitation ranging from less than 1000 to over 3000mm, and with marked orographic infl uences. there are distinct winter dry periods of differing onset, intensity and duration and brief midsummer droughts. summer rainfall is spatially uneven and hurricanes and tropical depressions can cause severe fl ooding, particularly in valleys and depressions. karst soils are extremely variable. steep slopes may be bare, while thicker soils in depressions and valley bases are often associated with bauxitic infi lls. vegetation varies from xerophytic scrub to wet tropical deciduous and coniferous forest, with many endemic species. most of the original forest has been cleared, with only fragments remaining in remote karst areas. 3. major sustainability issues in the karst the major sustainability issues in the caribbean karst are drought and water supply. the lack of surface drainage is particularly seasonal, and short-term dry season drought may be severe or extend over longer periods, leading to crop and livestock losses, bush fi res, and emergency distribution of water supplies (lashley & bandara, 2001). much progress has been made in the provision of urban water supplies via wells and pumps, but rural water supply still relies largely on rainwater collection in tanks from roofs and gutters. these collection systems, although simple and environmentally-friendly, have their limitations. storage capacity is limited, and supply is unreliable, characterized by defi cit or surplus. storage may be further compromised by evaporation and leakage, or by accidental contamination. springs remain the other major source of rural supply, particularly around karst edges. major perennial springs are generally reliable, but seasonal and ephemeral springs are less dependable. drought often requires water to be brought in by trucks from non-karst areas or from remaining sources within the karst. conversely, and perversely, fl ooding is also a great hazard, with serious short-term consequences, including human death, injury and displacement, and damage to homes and other structures (lashley & bandara, 2001). seasonal or intermittent fl ooding is an integral component of caribbean karst hydrology, and is particularly hazardous where drainage paths are provided by elongated, compound depressions or dry valleys. flooding may also occur where allogenic drainage exceeds the capacity of the karst drainage system, particularly in poljes, where such occurrences are suffi ciently frequent as to be predictable on a broadly seasonal basis. flooding may also result from fi lling and overtopping of the epikarstic reservoir. this is unpredictable and uncommon, but is usually localized and temporary. flooding on a broader scale may result from elevation of groundwater levels and upwelling of groundwater via estavelles. this may occur on a more-or-less predictable seasonal basis in larger, low-lying depressions, and it is this regional groundwater upwelling that represents the most serious fl ooding hazard, particularly in more densely populated, low lying areas. geologia croatica 63/2geologia croatica 152 central karst. by 2004, bauxite and alumina production amounted to 13.3 m mt and 4.08 m mt respectively (usgs, 2006). beyond the physical devastation of the karst by bauxite mining, the operations have caused the displacement of thousands of local residents and serious ground and surface water contamination. 5. future environmental change in the karst predictions for the caribbean are that anthropogenic climatic change will lead to increasing air and water temperatures, rising sea levels and changing weather patterns, including decreasing precipitation totals, and the increasing frequency of extreme events, such as droughts and hurricanes (nurse & sem, 2001; pelling & uitto, 2001; simms & reid, 2006). the most signifi cant and immediate changes will be related to rising sea levels and to changes in rainfall regimes, soil moisture budgets, prevailing wind speeds and directions, and patterns of wave action (nurse & sem, 2001). coastal locations, where socioeconomic activities, infrastructure and population are concentrated, will be particularly vulnerable, and the effects of all these changes will be magnifi ed in the karst. atmospheric carbon dioxide levels are increasing by about 1.0 percent per annum compounded, and sea level has been rising by nearly 2 mm per year. atmospheric carbon dioxide levels are predicted to reach 550 ppm by the mid 21st century (hulme & viner, 1998) and sea level may rise by as much as 5 mm per year over the next 100 years. this will have serious sustainability implications throughout the caribbean karst, both for natural biological systems and for social and economic development (nurse & sem, 2001). it is unclear what impact these changes might have upon karst processes, but changes in soil co2 levels have clear implications for dissolution rates as the soil is the primary source of co2 dissolved by percolating rainwater. temperatures across the caribbean have increased by 0.6 °c over the past 150 years, and are currently increasing by as much as 0.1 °c per decade, with a projected increase of 2.0 °c by 2100 (nurse & sem, 2001; peterson et al., 2002). precipitation trends and predictions are more variable, in part because of the inherent variability in caribbean rainfall. circulation models suggest enhanced climate change throughout the region, with increases in surface air temperature, decreases in diurnal temperature ranges, and a marginal decrease in rainfall of about 0.1–0.3 percent (nurse & sem, 2001). predictions also suggest increasing summer thermal stress, with more frequent dry season droughts and wet season fl oods. potential loss of biodiversity is another important element of environmental change in the caribbean, and the 2006 global biodiversity outlook (gbo) identifi es climate change as a primary “driver” of biodiversity loss (secretariat of the convention on biological diversity, 2006). projections suggest that climate change and sea-level rise will cause unfavourable shifts in biotic composition (nurse & sem, 2001; scbd, 2006). in the karst, the most damaging results of climate change will be those arising from changes in the karst hydrology as a result of more frequent dry season droughts and wet season fl oods. overall, the impact will be to exacerbate and magnify the existing situation, with increasing frequency of high magnitude events and greater extremes of drought and fl ooding. water resources are already limiting, and disruption of the karst hydrological cycle may lead to increasing aridity and desertifi cation, with concomitant impacts on future sustainability. increasing drought will further limit human access to rainwater and will also result in a diminution of recharge to the groundwater, placing an increased burden upon water resources in general (dacunha, 1989). in addition, fl oodwaters may contribute relatively little to groundwater resources, as well as potentially increasing contaminant loads. the availability of water resources will become increasingly critical in the karst, where water already is in short supply and reliant upon rainwater from small catchments or limited freshwater lenses. rising sea levels will also increase the risks of saline water intrusion into the restricted fresh water lenses, especially in smaller islands. related to water supply issues, arable land for crop agriculture is limited throughout the caribbean karst, and the prospect of land loss and increased aridity as a consequence of climate change and sea-level rise will threaten the sustainability of both subsistence and commercial agriculture. because water resources and agriculture are so climate sensitive, it is expected that these sectors will be adversely affected by future climate and sea-level change (dacunha, 1989; nurse & sem, 2001; fischer et al., 2002; parry et al., 2004). the other major impact of projected climate change will be an increase in fl ooding within the karstlands. floods will increasingly produce more serious short-term consequences, including human death, injury and displacement, and damage to homes and other structures. flooding may still be expected on a similar seasonal or intermittent basis, but it will remain problematic to predict its geographical distribution accurately. flooding will continue via distinct, but often complementary mechanisms, and will affect increased areas of the karst landscape. heavy and/or prolonged rains, associated with more intense tropical storms, will produce increased overland fl ow when surface and epikarstic infi ltration capacities are exceeded, particularly in elongated, compound depressions and dry valleys. there will also be increased fl ooding by allogenic drainage from non-karst terrains, particularly in poljes, which may be inundated for longer periods seasonally, if not permanently. such fl ooding may affect the function of estavelles and other discharge/recharge features. flooding as a result of fi lling and overtopping of the epikarstic reservoir will also become more common and extensive but will remain unpredictable and temporary. widespread fl ooding may result from elevation of groundwater levels and upwelling of groundwater via estavelles. this may still occur on a more-or-less predictable seasonal basis in larger, low-lying depressions, and it will remain the most serious fl ooding hazard, particularly in densely-populated, low-lying areas. increased groundwater levels and volumes may also lead to temporary increases day: challenges to sustainability in the caribbean karst geologia croatica 153 in spring discharge, which may in turn lead to stream fl ooding on the downstream sides of the karst. coastal fl ooding will also increase as sea level rises. 6. sustainability within the karst sustainability “....meets the needs of the present without compromising the ability of future generations to meet their own needs” (world commission on environment and development, 1987). in practice, sustainability is a complex issue and one which is diffi cult to defi ne in a specifi c operational sense (clark, 2007). it is usually employed with an anthropocentric focus, although it can be argued that this is not necessarily appropriate, and that a broader environmental, rather than social or economic framework may be more appropriate (serageldin & steer, 1994). a detailed consideration of the sustainability concept is beyond the remit of this paper. broadly, current human use of the caribbean karst is unsustainable, although some aspects, such as urban expansion, quarrying and industrialization, are clearly more pernicious than others, such as small-scale organic agriculture and ecotourism. sustainability in the karst may be illusory, particularly in light of contemporary and future environmental changes (day & chenoweth, 2009). sustainability, broad-scale environmental change and land use and land cover modifi cations within the caribbean karst must be understood in tandem (dale, 1997) and responses must be integrated to address the entire panoply of sustainability issues (hamilton-smith, 2006; unep, 2005, simms & reid, 2006). climate change will have environmental impacts at a variety of spatial and temporal scales, but more direct human impacts will override these in many instances. climate change and other human impacts on the caribbean karst will result in combinations of vulnerabilities, necessitating integration of environmental change parameters and the adoption of appropriate sustainability measures (challenger, 2002). there is an immediate need for comprehensive regional and national surveys of environmental conditions within the caribbean karst. recognition of the inherent characteristics of the karst needs to be at the forefront of such surveys, and the region’s karst sustainability issues need to be clearly identifi ed. it is paramount to recognize the karst drought and fl ooding hazards. a varietry of stakeholders – government agencies, ngos and communities should be involved. local and indigenous knowledge about conditions is paramount. scale issues also warrant attention, since impacts and responses will occur at a variety of spatial and temporal scales. proactive steps are required from regional bodies and national governments, but local community actions may ultimately prove more important. once the contemporary situation is understood, then strategies for mitigating future environmental change and promoting sustainability can be developed rationally and with specifi c reference to the karst. appropriate strategies may include the development and implementation of comprehensive land use policies and programs. provision of adequate water resources within the karstlands will involve measures such as improved rainfall retention, improved storage and distribution systems, development of alternative water sources, better management of supply and infrastructure, increased conservation, and application of improved technology, including desalinization. agricultural strategies may include growing more drought-resistant crops, and increased attention to maintenance of soil and water resources. the potential effects of climate change and anthropogenic pressures also need to be integrated into broader community planning and into tourism development. in a broad sense, the severity of both climatic and other anthropogenic impacts within the karst can best be reduced by appropriate land management and sustainable land use planning, including the expansion and maintenance of protected areas. all elements of natural and human-modifi ed ecosystems within the karst need to be taken into account. increased monitoring is required, and priority should be allocated to the maintenance and protection of natural “buffers” within the karst, such as natural vegetation, surface watersheds, caves and groundwater aquifers. although most caribbean nations now recognize the importance of resource protection for environmental, economic and social reasons, the ramifi cations of climate change and other human impacts increasingly require this to be a priority, particularly within the karst, where the potential risks to nature and human wellbeing are magnifi ed and accentuated. changing environmental conditions within the caribbean karst may well be a portent for the overall environmental health of the region, and the karst thus represents a potential barometer of human ability to respond to the very real challenges to environmental sustainability. acknowledgement research on caribbean karst has been supported by grants from uwm’s center for latin american and caribbean studies, and the mary jo read bequest to the uwm geography department. references challenger, b. (2002): linking adaptation to climate change and disastermitigation in the eastern caribbean: experiences and opportunities. http://www.onu.org.cu/havanarisk/papers_cchange3/ challenger.pdf clark, w.c. (2007): sustainability science: a room of its own.– proceedings of the national academy of sciences of the usa, 104/6, 1737–38. dacunha, l.v. (1989): climate change and water resources development.– in: berger, a., schneider, s. & duplessy, j.c. (eds.): climate and geosciences. nato asi series c: mathematical and physical sciences, 285, kluwer, dordecht, 639–660. dale, v.h. (1997): the relationship between land-use change and climate change.– ecological applications, 7/3, 753–769. day, m.j. (1993): human impacts on caribbean and central american karst.– in: williams, p.w. (ed.): karst terrains: environmental changes and human impact, catena supplement 25, cremlingendestedt, 109–125. day, m.j. (2009): eastern caribbean.– in: palmer, a. & palmer, m. (eds.): caves and karst of the usa. national speleological society, 332, 346–347. geologia croatica 63/2geologia croatica 154 day, m.j. & chenoweth, m.c. (2009): potential impacts of anthropogenic environmental change on the caribbean karst.– in: mcgregor, d., barker, d. & dodman, d. (eds.): global change and caribbean vulnerability, university of the west indies press, 100–122. fischer, g., shah, m.& van velthuizen, h. (2002): climate change and agricultural vulnerability.– international institute for applied systems analysis, laxenburg, austria. http://iiasa.ac.at/ research/luc/jb-report.pdf hamilton-smith, e. (2006): spatial planning and protection measures for karst areas.– acta carsologica, 35/2, 5–11. hulme, m. & viner, d. (1998): a climate change scenario for the tropics.– climatic change, 39/2–3, 145–176. lashley, b. & bandara, s.b. (2001): a bibliography of natural hazards in the caribbean.– caribbean disaster information network, kingston. nurse, l.a. & sem, g. (2001): small island states.– in: climate change 2001: impacts, adaptation and vulnerability, cambridge university press. pelling, m. & uitto, j.i. (2001): small island developing states: natural disaster vulnerability and global change.– environmental hazards, 3, 49–62. secretariat of the convention on biological diversity (2006): global biodiversity outlook 2, montreal: cbd. http: www.biodiv.org/doc/gbo2/cbd-gbo2.pdf serageldin, i. & steers, a. (1994): valuing the environment: proceedings of the first annual international conference on environmentally sustainable development. http://www.wds.worldbank. org/external/default/wdscontentserver/wdsp/ib/1994/09/01/ 000009265_3970311123054/rendered/pdf/multi_page.pdf simms, a. & reid, h (2006): up in smoke? latin america and the caribbean: the threat from climate change to the environment and human development. new economic foundation, new york. united nations environmental program (unep) (2005): caribbean environment outlook. unep, nairobi. united states geological survey (usgs) (2006): minerals yearbook, http://minerals.usgs.gov/minerals/pubs/myb.html watson, j., hamilton-smith, e., gillieson, d. & kiernan, k. (1997): guidelines for cave and karst protection. iucn, gland. watts, d. (1987): the west indies: patterns of development, culture and environmental change since 1492.– cambridge university press, cambridge. world commission on environment & development (wced) (1987): our common future (the brundtland report).– oxford university press, oxford. manuscript received november 18, 2009 revised manuscript accepted march 19, 2010 available online may 31, 2010 gourrat et al.indd hypelasma salevensis (favre, 1913) from the upper kimmeridgian of the french jura, and the origin of the rudist family requieniidae christian gourrat1, jean-pierre masse2 and peter w. skelton3* 1. introduction the stratigraphically oldest requieniid species on record was originally named matheronia salevensis by favre, in joukowsky & favre (1913). favre’s material came from the tithonian of mont salève (hautesavoie), se france (fig. 1). in recent years, it has also been reported from the upper kimmeridgian, in sections some 40 km to the north-west, in the southern jura (skelton, 1999), based on collaborative studies by the present authors on the upper jurassic to lower cretaceous rudists of the region. here, we describe the specimens of the species from the french jura in greater detail, and compare them with the type material. we also address the questions of the generic assignment of the species, and the characterization and evolutionary origins of the family requieniidae. 2. stratigraphical context the geological transect eastwards from the french southern jura towards the swiss alps is a well known example of facies diachroneity, testifying to the late jurassic progradation of a carbonate platform into the bassin dauphinois (gaillard et al., 1984). in kimmeridgian times, various platform-top facies spread eastwards across the southern jura, reaching as far as the cluse-du-fier, some 20 km west of annecy. by the tithonian, massive coraland rudist-rich limestones (calcaires coralliens des etiollets) were accumulating in the area of mont salève, south of geneva, and the entire regional succession was finally capped by tithonian–berriasian tidalites (figs. 1, 2). the kimmeridgian reef-associated fauna of the southern jura was documented from valfin (just north of the area shown in fig. 1b) in a classic monograph by de loriol & bourgeat (1888), while the succeeding ‘portlandian’ (= tithonian) fauna, from le salève (fig. 1b), was thoroughly described by joukowsky & favre (1913). more recent work on mont salève (deville, 1991) locates the rudist-rich beds just below and within the ‘membre des calcaires à oncoïdes des etiollets’ at the top of the calcaires coralliens des etiollets, around the tithonian/berriasian boundary (fig. 2). geologia croatica 56/2 139–148 7 figs. zagreb 2003 key words: requieniidae, rudists, taxonomy, jura, kimmeridgian, france. 1 société des naturalistes d’oyonnax, maison des sociétés, 34 rue paradis, 01100 oyonnax, france; e-mail: christian.gourrat@wanadoo.fr 2 centre de sédimentologie-paléontologie et upresa 6019 du cnrs, université de provence, f-13331, marseille cedex 3, france; e-mail: jean-pierre.masse@up.univ-mrs.fr 3* corresponding author: department of earth sciences, open university, milton keynes mk7 6aa, united kingdom; e-mail: p.w.skelton@open.ac.uk abstract the requieniid rudist species ‘matheronia’ salevensis favre, first described from the tithonian of mont salève, eastern france, is transferred to the genus hypelasma paquier, which is distinguished from matheronia by possession of a posterior myophoral ledge in the left (attached) valve. diminutive specimens from the upper kimmeridgian of the southern jura are described and placed in this species. hence, hypelasma salevensis (favre) is the stratigraphically oldest known member of the family requieniidae. it may also provide another example of phyletic size increase among rudists. revised diagnoses are given for the family, genus and species. the main distinction between the requieniids and the diceratids, from among which they arose, concerns the angle between the coiling axis of the left valve and the commissural plane. in diceratids, this angle is large, such that the often sub-equal umbones tend to twist outwards from the commissural plane, so avoiding mutual interference. in requieniids, by contrast, this angle is small, such that the prominent umbo of the left valve tends to coil across the commissural plane in trochospiral to helicospiral fashion, while that of the right valve is suppressed in compensation, producing an exogyriform morphology. the requieniid modification of growth geometry, already present in h. salevensis, generated an extended basal surface on the flattened anterior wall of the left valve, implying specialized adaptation of these rudists as frictional or attached clingers. requieniid ancestry should be sought among species of the preexisting diceratid genera epidiceras or plesiodiceras, which also attached by the left valve. although plesiodiceras is favoured by its already more or less operculiform right valve and relatively small size, the derived condition of its posterior myophoral organisation is problematical. however, its juvenile shell shows some similarity of external form to h. salevensis, suggesting the possibility of paedomorphic evolution. 140 geologia croatica 56/2 141gourrat, masse & skelton: hypelasma salevensis (favre, 1913) from the upper kimmeridgian... the stratigraphy and palaeoenvironments of the upper kimmeridgian in the southern jura have been revised in detail by enay (1965) and bernier (1984). in the area around saint-germain-de-joux (ain) (fig. 1b), enay (1965) gave the name ‘couches de prapont’ to coraland rudist-rich bioclastic limestones, equivalent to those at valfin. he noted that this unit was split into lower and upper parts by a distinctive and widespread, oncolite-rich bed (‘le banc à momies intermédiaire’), which bernier (1984) named the ‘calcaires de la semine’ (fig. 2). bernier (1984, p. 587–589 and 615) inferred that the entire formation of the couches de prapont was probably confined to the upper kimmeridgian (eudoxus to beckeri zones), based on scarce ammonite evidence. the ‘couches du chailley’ (micritic limestone with burrows), which overlie this formation (fig. 2), contain the ammonite gravesia irius (d’orbigny) (enay, 1966). though originally referred to the ‘portlandien inférieur’, this species has more recently been recorded in the uppermost kimmeridgian aulacostephanus (a.) autissiodorensis zone at kimmeridge bay itself (morgans-bell et al., 2001, with associated online graphic log). hence the restriction of the couches de prapont to the upper kimmeridgian can now be asserted with greater confidence. our specimens of ‘m.’ salevensis were collected by the senior author from marchon (commune d’arbent), on the northern side of oyonnax (ain), and to the east of moulin de charix (‘coupe de chailley’, in bernier, 1984, p. 157–167), near saint-germain-de-joux (fig. 1b). at oyonnax, they are associated with coral biostromes in the uppermost kimmeridgian ‘couches de prapont supérieures’ (fig. 2; see also bernier, 1984, p. 245–252, though his section was along strike, to the sw of oyonnax). in the chailley section, they were found at a lower stratigraphical level, in the ‘couches de prapont inférieures’ (bernier, 1984, p. 162), associated with abundant specimens of the small diceratid rudists epidiceras guirandi (de loriol) and plesiodiceras munsteri (goldfuss). fig. 1 localities: (a) situation of study area (boxed) in france; (b) main localities (stars) for specimens of hypelasma salevensis (favre) described in text. fig. 2 summary stratigraphical sections (see fig. 1 for localities). approximate thicknesses of units based on bernier (1984) for oyonnax and chailley, and deville (1991) for salève. at oyonnax, the couches de prapont inférieures are represented by the ‘calcaires oolithiques de corveissiat’. at chailley, the ‘marnes des abergements’ (= ‘calcaires à ptérocères’) are included here in the lower half of the unit labelled couches du chailley. 140 geologia croatica 56/2 141gourrat, masse & skelton: hypelasma salevensis (favre, 1913) from the upper kimmeridgian... 3. systematic palaeontology abbreviations: lv – left (in this case, attached) valve; rv – right (in this case, free) valve. annotations to synonymy list are according to matthews (1973). superfamily hippuritoidea gray, 1848 family requieniidae douvillé, 1915 emended diagnosis: strongly inequivalve rudists attached by the larger lv. lv coiled trochospirally to helicospirally around an axis that is oriented at a small angle with respect to the commissural plane, so generating a broadly extended basal surface along the anterior valve wall. rv operculiform to more or less inflated posteriorly, with suppressed umbo. remarks: douvillé’s (1915) original definition of the family requieniidae (‘réquiénidés’) was essentially based on taxonomic composition, and lacked an explicit diagnosis of the characters that united its constituents. thus he envisaged it as defined by the inclusion of the classic urgonian genera, requienia matheron, toucasia munier-chalmas and matheronia munier-chalmas, which had originally all been contained within matheron’s (1842) conception of the genus requienia. in their description of the family, dechaseaux et al. (1969) noted the strongly inequivalve condition of the shell and its attachment by the lv. otherwise, however, their diagnosis was a mixture of primitive character states shared with the diceratids (hence not diagnostic of requieniids per se), and derived character states inconsistently distributed among requieniid genera. the plan of the dentition cited by them (one tooth in the lv, two in the rv), even including the incipient posterior tooth in the lv, is shared with the diceratids (see, for example, skelton & smith, 2000, fig. 1b), and is thus primitive. the so-called ‘siphonal bands’ are present only in some requieniid taxa (masse, 1994). the alternatives given for the arrangement of the myophores are again either shared with the diceratids, or derived only in certain requieniid taxa (e.g., the suppression of the posterior myophore in the lv of matheronia). hence, no clear picture emerges from dechaseaux et al. (1969) of shared derived character states (synapomorphies) that exclusively unite all the genera currently assigned to the family. in order to test for requieniid monophyly, and hence establish a reliable diagnosis for the family, it is necessary to take a cladistic perspective. skelton & smith (2000) substantiated a primary division of the rudists into two major clades (sister groups) according to whether attachment to the substrate was by the lv or by the rv. the clade of rudists attached by the lv comprises just the requieniids together with most of the diceratid genera. despite the historical lack of an explicit diagnosis for the requieniidae, authors have broadly agreed on its generic composition (e.g., kutassy, 1934; dechaseaux et al., 1969; masse, 1994, and yanin, 1995, although the last author split it into three families, nevertheless united as a clade in his fig. 12). this agreement suggests the intuitive recognition of some shared derived character or set of characters that distinguishes a requieniid clade from the (paraphyletic) diceratids. the strong relative reduction of the rv noted both by dechaseaux et al. (1969) and skelton & smith (2000) is a promising contender for this role, but is insufficient without further qualification, because plesiodiceras – which has never been regarded as a requieniid – also has a much reduced rv. what does appear to be peculiar to the requieniids is their particular mode of strongly inequivalve growth. the larger lv coils trochospirally to helicospirally around an axis that is oriented at a small angle to the commissural plane (fig. 3a). its umbo thus tends to pass across the commissural plane after half a whorl of growth; that of the rv is suppressed in compensation – analogously to the mode of growth in the oyster exogyra (although the latter grew opisthogyrally, rather than prosogyrally). the effect of this strongly inequivalve pattern of growth was to provide a broad area of sustained contact with the substratum on the flattened anterior face of the lv (masse, 1994, fig. 2). such a growth geometry is strikingly apparent even in the earliest requieniids, described herein. in the diceratids, by contrast, the axis of coiling of the attached valve is oriented at a much larger angle with respect to the commissural plane, with the effect that the umbo twists outwards, away from the commissural plane (fig. 3b). this growth geometry avoids mutual interference of the enlarged umbones in sub-equivalve forms, but even in the markedly inequivalve plesiodiceras, the tightly spirogyrate umbo of the adult lv likewise tends to twist away from the commissural plane, thereby distancing the adult growth margin from a discrete apical area of attachment. the distinguishing characteristic of the requieniid clade thus seems to be specialized adaptation fig. 3 diagram showing characteristic growth geometry of left valve (lv) in (a) requieniids, with a small angle between the coiling axis (vertical line) and the commissural plane (hatched), and (b) diceratids, with a relatively large angle. size varies according to species. 142 geologia croatica 56/2 143gourrat, masse & skelton: hypelasma salevensis (favre, 1913) from the upper kimmeridgian... as exogyriform frictional to attached clingers (gili et al., 1995). genus hypelasma paquier, 1897 type species: hypelasma colloti paquier, 1897. diagnosis: small to medium-sized requieniid. lv with low rate of expansion, producing prominent umbo that tends to project markedly across commissural plane, and with acute antero-ventral carina that becomes rounded in last fraction of a whorl, bordering flattish basal (anterior) surface. rv with raised, more or less carinate posterior margin. small but distinct posterior myophoral ledge in lv, passing under hinge plate, opposed by slightly outwardly tilted projecting shelf attached to hinge plate in rv. anterior adductor insertions on inner walls of both valves. remarks: the generic status of the species ‘m.’ salevensis favre has, from the start, been problematical. in our view, as discussed below, it should be included in the genus hypelasma, as stated by yanin (1995, p. 109). in order to address this issue, we illustrate diagrammatically some of the pertinent characters of the cretaceous type species of matheronia, m. virginiae (gras) (fig. 4a), and hypelasma (fig. 4b), as well as some of the type specimens of ‘m.’ salevensis (fig. 5), for comparison. favre, in joukowsky & favre (1913, p. 413), noted the similarity of ‘m.’ salevensis to hypelasma, in its possession of a rudimentary posterior myophoral ledge in the lv (fig. 5f, arrowed). such a feature is seen in the type species of hypelasma (fig. 4b), but not in that of matheronia, in which the adductor muscle inserted onto the inner face of the posterior valve wall in the lv (fig. 4a). yet favre decided against placing his new species in hypelasma, stating that it lacked the raised posterior side of the rv that is characteristic of the latter genus (fig. 4b), and had a relatively well developed anterior tooth socket in the lv. he regarded its general form and hinge characters as most like those of another tithonian species, matheronia (monnieria) romani paquier (for which he regarded the subgeneric distinction as unjustified). favre concluded that ‘m.’ salevensis was ancestral to the other species of matheronia, and that this group showed a progressive reduction in relative size of the hinge plates from ‘m.’ salevensis onwards. however, he proposed that hypelasma, too, had been derived from the new species, involving the enlargement of the posterior myophoral ledge in the lv, which led on, he suggested, to the diagnostic salient myophore of toucasia. later general reviews of rudist systematics have mostly treated both monnieria and hypelasma as sub-genera of matheronia (e.g. kutassy, 1934; dechaseaux, 1952; dechaseaux et al., 1969). however, this has had the undesirable effect of rendering matheronia as a broadly defined paraphyletic genus that groups all the various pre-hauterivian requieniids together with the lineage that includes the younger type species (m. virginiae: uppermost barremian to lower aptian; masse, 1996). such a broad generic concept obscures basal phylogenetic relationships within the requieniid clade, and we consider the retention of hypelasma as a separate genus (as in masse, 1994, p. 331) to be a useful step towards resolving this problem. if the complete suppression of the posterior myophore in the lv (as in fig. 4a) can be regarded as a diagnostic derived character state in the genus matheronia (by outgroup comparison with the diceratids), then hypelasma, with its residual posterior myophore (fig. 4b), should remain excluded from that genus. a further distinction concerns the posterior myophore of the rv. in the type species of matheronia, this structure appears as a buttress-like swelling in transverse section (fig. 4a; cf. masse, 1996, pl. 5, fig. 5), but in hypelasma, by contrast, it forms a projecting shelf (fig. 4b; cf. paquier, 1897, fig. 2). the difference probably reflects the relatively greater compression of the rv (again, a more derived condition) in matheronia, which left no space fig. 4 diagrammatic posterior to anterior sections across shells (not to scale) of (a) matheronia virginiae (gras) and (b) hypelasma colloti paquier, illustrating some of the principal differences between them. the relatively thicker outer shell layer of (a), with coarsely lamellose growth rugae on the (basal) anterior face, is typical of the type species, but not of some of the stratigraphically older species of matheronia. key: lv, left valve; pm(s) posterior myophore(s); rv, right valve. (a) based on masse (1996, pl. 5, fig. 5); (b) on paquier (1897). 142 geologia croatica 56/2 143gourrat, masse & skelton: hypelasma salevensis (favre, 1913) from the upper kimmeridgian... for the extension of the body cavity behind the myophore. another distinction is the development of a buttress-like anterior myophore in the rv of matheronia (fig. 4a), matching the posterior one, which contrasts with the relatively depressed anterior adductor insertion site on the inner wall of that valve in hypelasma (fig. 5i). the oldest toucasia recorded so far is from the hauterivian (masse et al., 1998) and its evolutionary origins remain unclear. toucasia can be distinguished from hypelasma by its possession of a discrete posterior myophoral ledge in the rv that passes behind the hinge plate, like that in the lv (see masse, 1994), instead of joining it, as it does in hypelasma (fig. 5i). this appears to be a derived condition in toucasia, shared with requienia (masse, 1994), and again excluding hypelasma. hence, we propose that hypelasma should be maintained as a discrete genus. we can now return to the question of the generic status of ‘m.’ salevensis. from the argument stated above, this species’ possession of a posterior myophoral ledge in the lv, albeit small (fig. 5f), should, after all, place it in hypelasma, not matheronia. we must therefore re-consider favre’s objections to this assignment (in joukowsky & favre, 1913). although the rv of h. salevensis is indeed somewhat less convex than that of h. colloti (fig. 4b), it is nevertheless relatively more raised around the posterior than the anterior side, thereby creating a low, obtusely rounded carina there (fig. 5a, g). hence, the only, slight, difference between the two species is in the degree of compression of the valve, which is hardly sufficient for distinction at the generic level, especially as such external aspects of morphology may vary with individual age and ecological context. moreover, favre’s comment regarding the anterior tooth socket of the lv appears to have been fig. 5 selected type specimens of hypelasma salevensis (favre) from around the tithonian/berriasian boundary of mont salève (hautesavoie), france, re-photographed from the favre collection at the muséum de la ville de genève. (a) no. 28911 (joukowsky & favre, 1913, pl. 24, fig. 5), posterior view of articulated shell; (b) no. 28906 (joukowsky & favre, 1913, pl. 24, fig. 3), anterior view of left valve; (c) no. 28915 (joukowsky & favre, 1913, pl. 24, fig. 7), anterior view of left valve; (d) no. 28928 (joukowsky & favre, 1913, pl. 24, fig. 9), commissural view of prepared left valve; (e) no. 28914 (joukowsky & favre, 1913, pl. 24, fig. 8), commissural view of prepared left valve, specimen designated as lectotype herein; (f) enlarged view of internal features of (e), white arrow indicates posterior myophore; (g, h) no. 28935 (joukowsky & favre, 1913, pl. 24, fig. 13), right valve, external and internal views, respectively; (i) no. 28935, another specimen (joukowsky & favre, 1913, pl. 24, fig. 12), enlarged oblique internal view of rv from ventral side; white arrow indicates posterior myophore. scale bars: 1 cm for a–e and g, h; 0.5 cm for f, i. 144 geologia croatica 56/2 145gourrat, masse & skelton: hypelasma salevensis (favre, 1913) from the upper kimmeridgian... based on a single specimen (fig. 5e). only one other lv in the type series shows its dentition (fig. 5d), and it is clear even from this example that the relative size of the anterior tooth socket is quite variable. indeed, the dentition in this latter specimen appears remarkably similar to that of h. colloti, as illustrated by paquier (1897). it is worth recording in this context that douvillé (1915, p. 384) likewise noted the rather variable development of the anterior tooth socket among requieniids and advised against exaggerating its importance for taxonomy. so there is no compelling justification, after all, for excluding favre’s species from hypelasma. in addition, we note the projecting, ledge-like form of the posterior myophore in the rv (fig. 5h, i), which, as mentioned above, is typical of hypelasma (fig. 4b). consequently, we hereby formally re-classify favre’s species as hypelasma salevensis (favre). with the re-instatement of hypelasma as a distinct genus, it is perhaps also appropriate to re-confirm its inclusion in the family requieniidae, as diagnosed above, on the basis of its trochospirally to helicospirally coiled lv with a broad anterior face of original attachment (fig. 5b, c). hypelasma salevensis (favre, in joukowsky & favre, 1913) fig. 5a–i; fig. 6a–j v. 1888 diceras bourgeati p. de loriol; de loriol, pl. 29, fig. 2 (non fig. 1). v*1913 matheronia salevensis n.sp.; favre, p. 410– 413, pl. 24, figs. 1–14. 1931 matheronia salevensis favre; yin, pl. 13, figs. 5–6, pl. 14, fig. 1. fig. 6 specimens of hypelasma salevensis (favre) from the upper kimmeridgian of oyonnax and chailley (ain), french jura (gourrat collection, société des naturalistes d’oyonnax) (a-g), and valfin (guirand collection, université claude-bernard, lyon) (h-j). (a, b) no. j7 (chailley), articulated shell, viewed from right side and in anterior view, respectively; (c) no. j1 (chailley), articulated shell, posterior view; (d, e) no. j2 (oyonnax), partial articulated shell, (d) showing transverse section of myocardinal apparatus of right valve (posterior myophore arrowed; hinge plate to right), and (e) in ventral aspect, with ventral wall of left valve broken away to reveal projecting right valve posterior myophore (at left) and tooth (at right); (f, g) no. j4 (oyonnax), partial articulated shell, in (f) posterior view, and (g) ventral aspect, with ventral wall of left valve broken away to reveal projecting right valve posterior myophore (arrowed) and tooth (at right); (h, i, j) no. ml14236, left valve, originally described by de loriol as ‘diceras bourgeati’ (in de loriol & bourgeat, 1888, pl. 29, fig. 2), (h) in anterior view, (i) in commissural view, with (j) enlargement of the internal features (posterior myophore arrowed). scale bars: 1 cm for a–h; 0.5 cm for j. 144 geologia croatica 56/2 145gourrat, masse & skelton: hypelasma salevensis (favre, 1913) from the upper kimmeridgian... v 1999 matheronia salevensis joukowsky & favre; skelton, p. 86, pl. 3, figs. 7, 8. type material: the favre collection is housed in the muséum de la ville de genève (département gepi). in his description, favre did not designate a holotype from the 100 specimens from le salève (les etiollets, chavardon) that he reported having studied (only a few of which he illustrated). nor, to our knowledge, has any later author selected a lectotype from among his syntypes, some of which are re-illustrated in fig. 5 herein. of the specimens illustrated in joukowsky & favre (1913, pl. 24, figs. 1–14), the prepared lv shown there as fig. 8 (specimen no. 28914) most clearly exhibits the distinctive incipient posterior myophore as well as the dental plan of the species (fig. 5e, f), despite showing an atypically large ratio of commissural height to total valve height in the lv (d/d in fig. 7). accordingly, we designate this specimen as the name-bearing lectotype of the species (re-illustrated herein as fig. 5e and f), as provided for in article 74 of the international code of zoological nomenclature (ride et al., 1999), and the remaining specimens thereby become paralectotypes. diagnosis: relatively small species of hypelasma (dorso-ventral commissural diameter up to 3.5 cm). lv sometimes exceeding 3 whorls in adult; rv sub-operculiform, though with slightly raised posterior margin, producing weak carina. hinge plates relatively large, occupying up to a third of the commissural area. posterior myophoral ledge in lv weakly developed. material studied: besides some of the type specimens (fig. 5), we have studied nine specimens from the upper kimmeridgian of the southern jura, from the rudist collections of the senior author housed at the société des naturalistes d’oyonnax, and comprising three articulated specimens, three lvs and three more lvs with partial rvs. some of these specimens are illustrated in fig. 6a–g. also shown is a single lv from valfin (fig. 6h–j), from the guirand collection at the université claude-bernard, lyon (specimen no. ml14236), which was originally described by de loriol as ‘diceras bourgeati’ (in de loriol & bourgeat, 1888, pl. 29, fig. 2). description: the specimens from the jura are generally smaller (lv height, from ventral margin to top of umbo, 26 to 40 mm) than those from le salève (lv height, 36 to 56 mm), though with some overlap in size (fig. 7). otherwise, they conform well to favre’s description, with only minor differences in the internal features of the few specimens in which they can be seen. the lvs of the jura specimens show the low expansion rate typical of the species, yielding a trochospiral (fig. 6c, f) to helicospiral (fig. 6a, e) external form, with 2–3 whorls in adult shells. the broad basal area on the anterior wall of the lv (fig. 6b) is bounded by the characteristically sharp, but later rounded, anteroventral carina, and shows coarse growth rugae, accompanied, in one example (not illustrated), by some weak longitudinal ribbing. the valfin specimen (fig. 6h, i) agrees in all these particulars and plots comfortably within the morphometric field of our specimens (fig. 7). the rv (fig. 6a, c, f) is almost operculiform, though slightly raised posteriorly, with a weakly expressed posterior carina. the internal features can be discerned only in two of the incomplete, partially articulated specimens (fig. 6d–e and g), though they are also visible in the lv from valfin (fig. 6i–j). most importantly, although some of the ventral valve margin is missing from the latter specimen, it does show a small part of the weak posterior myophore passing beneath the hinge plate (fig. 6j, arrowed). the posterior myophore of the rv is a strongly projecting shelf extending ventrally from the hinge plate (fig. 6d–e and g, arrowed). though perhaps a little more erect than in the specimens from le salève fig. 7 bivariate scatter of dorso-ventral commissural height (= height of right valve), (d), versus full height of left valve, from ventral margin to top of umbo, (d), for specimens of hypelasma salevensis favre from the upper kimmeridgian of oyonnax and chailley (ain), and valfin (jura), and around the tithonian/ berriasian boundary at mont salève (haute-savoie), eastern france. the data point for the lectotype, selected herein, is boxed. 146 geologia croatica 56/2 147gourrat, masse & skelton: hypelasma salevensis (favre, 1913) from the upper kimmeridgian... (e.g. fig. 5h, i), its form and position are similar, and match the diagnosis for the genus (cf. fig. 4b). remarks: from the above description, it is evident that the valfin specimen shows no significant differences, either in size or form, from our specimens of the same age from a little farther south, and may accordingly be classified with them. its inclusion in diceras bourgeati de loriol by de loriol (in de loriol & bourgeat, 1888) was obviously erroneous. in erecting the latter species, de loriol stated that it attached by the right valve, and his description clearly relates to the large, articulated sub-equivalve specimen that he illustrated in his pl. 29, fig. 1, in which an attachment scar is indeed visible on the rv. that species can unquestionably be assigned to the genus diceras lamarck, but, from de loriol & bourgeat (1888), only the single specimen shown in fig. 1 of pl. 29 can be assigned to it (for which it becomes the holotype, by monotypy). by contrast, the specimen shown in their pl. 29, fig. 2 (= fig. 6h–j herein) is hereby transferred to h. salevensis. it is also apparent from the above description that the jura specimens are closely comparable in external form to those from mont salève, differing from them only in mean size (fig. 7). their myocardinal arrangements likewise appear similar. with so few specimens available in which internal features can be observed, no significance can yet be attached to the minor differences between them. moreover, the bivariate scatter in fig. 7, relating dorso-ventral commissural diameter (d, also equivalent to rv height) to the full height of the lv (d), shows a remarkable consistency of trend from the jura specimens to those from mont salève. the simplest interpretation is that the two sets of specimens come from a single species (h. salevensis) that shows phyletic size increase – an evolutionary pattern that has been documented in a number of other rudist lineages (steuber, 2003). similar small requieniids are not uncommon in tithonian platform carbonates elsewhere, and yin (1931), for example, reported the species from the tithonian of gard and l’hérault. re-study of such material would allow the hypothesis of phyletic size increase to be tested. based on the description of paquier (1897), h. colloti appears to be somewhat larger than h. salevensis, the posterior part of its rv is more raised, and the posterior myophoral ledge in the lv has slightly more marked development. as long as favre’s material was believed to be of early tithonian age (as proposed in joukowsky & favre, 1913), h. colloti could have been considered as a possible descendent chronospecies, continuing the trend for phyletic size increase. however, according to deville (1991), the salève specimens come from around the tithonian/berriasian boundary, so may be even younger than paquier’s material. further comparative study of the two species is thus needed to establish the relationship between them more clearly. 4. the evolutionary origin of hypelasma salevensis h. salevensis makes an abrupt appearance in the upper kimmeridgian of the southern jura alongside several diceratid species (skelton, 1999), all of larger shell size. h. salevensis is likely to have been derived from one of the species of the two pre-existing diceratid genera in which attachment was by the lv, namely epidiceras and plesiodiceras (diceras can be rejected because it attached by the rv). despite some variation in the degree of relative reduction of the rv, none of the species of epidiceras approaches the characteristic requieniid growth geometry of hypelasma, and only one (e. guirandi (de loriol)) comes close to its smaller shell size. favre (in joukowsky & favre, 1913) suggested that h. salevensis was derived from plesiodiceras munsteri goldfuss, on the basis of the similarity of their more or less operculiform rvs. even in the kimmeridgian specimens of h. salevensis, however, the posterior adductor muscle inserted onto a low myophoral ledge in the lv, which passes beneath the hinge plate, instead of a myophoral shelf adjoining the hinge plate, as seen in p. munsteri. moreover, the posterior muscle insertions in plesiodiceras extend dorsally onto the posterior parts of the hinge plates, whereas in h. salevensis they are wholly ventral to the hinge plates, as in epidiceras. these differences leave the proposed link between plesiodiceras and hypelasma open to question, because the myophoral condition of plesiodiceras appears relatively more derived. in addition, the adult lv of p. munsteri has a tightly ascending spiral form, lacking a pronounced antero-ventral carina, associated with its upright growth habit, in contrast to the broadly trochoto helicospiral, strongly carinate shape of the same valve in h. salevensis. nevertheless, the juvenile lv of p. munsteri (up to 1–2 cm dorso-ventral commissural diameter), which represents the stage of attachment to the substrate, is broadly spiral and carinate, with a large basal area on its anterior face, as in hypelasma. this similarity suggests the possibility of heterochrony: h. salevensis could have evolved from p. munsteri (or another species), as a paedomorphic derivative. the relatively small size of the oldest specimens of h. salevensis would also be consistent with this interpretation. however, testing the hypothesis will require knowledge of the condition of the posterior adductor insertions in the juvenile shell of p. munsteri, which is presently lacking. acknowledgements we are most grateful to dominic orbette (société des naturalistes d’oyonnax) for his helpful participation in our joint fieldwork, and to danielle decrouez (muséum de la ville de genève) and michel philippe (centre de conservation et d’étude des collections, 146 geologia croatica 56/2 147gourrat, masse & skelton: hypelasma salevensis (favre, 1913) from the upper kimmeridgian... université claude-bernard, lyon) for providing access to specimens in their care. prof. r. enay (université claude-bernard, lyon, france), andré strasser (department of geosciences, university of fribourg, switzerland) and angela coe (department of earth sciences, open university, uk) provided us with valuable information on the literature concerning, respectively, the regional stratigraphy of the southern jura, the geology of mont salève and kimmeridgian chronostratigraphy, which we gratefully acknowledge. the photographic composites of figs. 5 and 6 were skilfully prepared from our digital photographs by andrew lloyd (department of earth sciences, open university, uk). the paper also benefited from the careful and constructive reviews of bob scott and thomas steuber. 5. references bernier, p. (1984): les formations carbonatées du kimmeridgien et du portlandien dans le jura méridional – stratigraphie, micropaléontologie, sédimentologie [the kimmeridgian and portlandian carbonate formations of the southern jura – stratigraphy, micropalaeontology, sedimentology – in french].– documents des laboratoires de géologie, lyon, no. 92, fasc. 1, 2. université claudebernard lyon 1, 730 p. dechaseaux, c. (1952): classe des lamellibranches – étude systematique [class of lamellibranchs – systematics – in french].– in: piveteau, j. (ed.): traité de paléontologie, ii. masson et cie, paris, 261–364. dechaseaux, c., cox, l.r., coogan, a.h. & perkins, b.f. (1969): superfamily hippuritacea gray, 1848.– in: moore, r.c. (ed.): treatise on invertebrate paleontology, part n, mollusca 6, bivalvia, 2. university of kansas, lawrence, kansas & geological society of america, n749–817. deville, q. (1991): stratigraphie, sédimentologie et environnements de dépôts, et analyse séquentielle dans les terrains entre le kimméridgien supérieur et le valanginien du mont-salève (haute-savoie, france) [stratigraphy, sedimentology and depositional environments, and sequence analysis of the upper kimmeridgian to valanginian succession of mont-salève (haute-savoie, france) – in french].– unpubl. phd thesis, university of geneva, 141 p. douvillé, h. (1915): les réquienidés et leur evolution [the requieniidae and their evolution – in french].– bulletin du société géologique de france, 4/14, 383–389. enay, r. (1965): les formations coralliennes de saint-germain-de-joux (ain) [the coralliferous formations of saint-germain-de-joux (ain) – in french].– bulletin du société géologique de france, 7/7, 23–31. enay, r. (1966): le genre gravesia (ammonitina, jurassique) dans le jura français et les chaines subalpines [the genus gravesia (ammonitina, jurassic) in the french jura and the sub-alpine chains – in french].– annales de paléontologie (invertébrés), 52, 95–105. gaillard, c., arnaud, m., bernier, p., bodeur, y., contini, d., elmi, s., lathuilière, b., menot, j.-c., monleau, c., pascal, a. & thierry, j. (1984): bioconstructions jurassiques [jurassic bioconstructions – in french].– in: debrand-passard, s., courbouleix, s. & lienhardt, m.-j. (eds.): synthèse géologique de sud-est de la france, volume 1, stratigraphie et paléogéographie. mémoire du bureau de recherches géologiques et minières, 125, 276–281. gili, e., masse, j.-p. & skelton, p.w. (1995): rudists as gregarious sediment-dwellers, not reef-builders, on cretaceous carbonate platforms.– palaeogeography, palaeoclimatology, palaeoecology, 118, 245–267. gray, j.e. (1848): on the arrangement of the brachiopoda.– annals and magazine of natural history, 2/2, 435–440. joukowsky, e. & favre, j. (1913): monographie géologique et paléontologique du salève (haute savoie, france) [monograph on the geology and palaeontology of salève (haute savoie, france) – in french].– mémoire de la société de physique et d’histoire naturelle de genève, 37, 295–523. kutassy, a. (1934): fossilium catalogus, i. animalia, pars 68, pachydonta mesozoica (rudistis exclusis) [catalogue of fossils, i. animalia, part 68, mesozoic pachyodonts (excluding rudists) – in latin].– neubrandenburg (gustav feller), 202 p. loriol, p. de & bourgeat, e. (1888): études sur les mollusques des couches coralligènes de valfin (jura) [studies on the molluscs of the coralliferous beds of valfin (jura) – in french].– mémoires de la société paléontologique suisse, 13–15, 369 p. masse, j.-p. (1994): l’évolution des requieniidae (rudistes) du crétacé inférieur: caractères, signification fonctionelle adaptative et relations avec les modifications des paléoenvironnements [the evolution of the lower cretaceous requieniidae (rudists): characters, functional adaptive interpretation and links with palaeoenvironmental modifications – in french].– geobios, 27, 321–333. masse, j.-p. (1996): lower cretaceous rudist biostratigraphy of southern france – a reference for mesogean correlations.– revista mexicana de ciencias geologicas, 12 (1995), 236–256. masse, j.-p., gourrat, c., orbette, d. & schmuck, d. (1998): hauterivian rudist faunas of southern jura (france).– geobios, mém. spéc., 22, 225–233. matheron, p. (1842): catalogue méthodique et descriptif des corps organisés fossiles du département des bouchesdu-rhône et lieux circonvoisins [systematic and descriptive catalogue of fossils from the department of bouchesdu-rhône and neighbouring areas – in french].– carnaud fils, marseille, 269 p. matthews, s.c. (1973): notes on open nomenclature and on synonymy lists.– palaeontology, 16, 713–719. morgans-bell, h.s., coe, a.l., hesselbo, s.p., jenkyns, h.c., weedon, g.p., marshall, j.e.a., tyson, r.v. & williams, c.j. (2001): integrated stratigraphy of the kimmeridge clay formation (upper jurassic) based on exposures and boreholes in south dorset, uk.– geological magazine, 138, 511–539. 148 geologia croatica 56/2 paquier, v. (1897): sur quelques diceratinés nouveaux du tithonique [on some new tithonian diceratids – in french].– bulletin du société géologique de france, 3/25, 843–851. ride, w.d.l., cogger, h.g., dupuis, c., kraus, o., minelli, a., thompson, f.c. & tubbs, p.k. (eds.) (1999): international code of zoological nomenclature, fourth edition.– international trust for zoological nomenclature, c/o the natural history museum, london, uk., 306 p. skelton, p.w. (1999): synoptic guide to kimmeridgian rudists for the kelheim field visit.– in: höfling, r. & steuber, t. (eds.): fifth international congress on rudists, abstracts and field trip guides. erlanger geologische abhandlungen, 3, 83–89. skelton, p.w. & smith, a.b. (2000): a preliminary phylogeny for rudist bivalves: sifting clades from grades.– in: harper, e.m., taylor, j.d. & crame, j.a. (eds.): the evolutionary biology of the bivalvia. geological society of london, special publication, 177, 97–127. steuber, t. (2003): strontium isotope stratigraphy of cretaceous hippuritid rudist bivalves: rates of morphological change and heterochronic evolution.– palaeogeography, palaeoclimatology, palaeoecology, 200, 221–243. yanin, b.t. (1995): the system, phylogeny and evolution of rudists [in russian].– pin ran, moscow, 195 p. yin, t.h. (1931): étude de la faune du tithonique coralligène du gard et de l’herault [study of the fauna from the tithonian coralliferous beds of gard and herault – in french].– travaux du laboratoire de géologie de l’université de lyon, mémoire, 14/18, 197 p. manuscript received march 10, 2003. revised manuscript accepted november 04, 2003. 1. introduction pedogenic iron oxides and manganese oxides and hydroxides frequently occur in soils of different climatic regions. due to their high pigmenting capacity they may influence the colour of soils or particular soil horizons. manganese oxides and hydroxides have a stronger pigmenting effect upon soils than iron oxides and tend to overwhelm their colour when both constituents are present (schwertmann & fanning, 1976). iron oxides may occur evenly dispersed throughout the soil, concentrated in particular horizons or in certain morphological features such as mottles and nodules distribution of iron and manganese in terra rossa from istria and its genetic implications goran durn, dragutin slovenec and marta »ovi∆ (schwertmann & taylor, 1989). manganese oxides and hydroxides mainly occur as coatings on other soil particles, as concretions and mottles, in cracks and veins or are mixed with iron oxides and other soil constituents in nodules (fanning & fanning, 1989; mck e n z i e, 1989). the most common pedogenetic iron oxides in soils are goethite and haematite. lepidocrocite, maghemite and ferrihydrite are less common and occur in more specific pedogenic environments. although manganese oxides and hydroxides in soils are often reported to be amorphous (e.g. sidhu et al., 1977) this is probably caused by difficulties in detecting small concentrations of poorly crystalline phases as with amorphous iron oxides (s c h w e r tmann & taylor, 1989). according to mck e n z i e (1989), the most common crystalline manganese oxides in soils are birnessite, vernadite, lithiophorite and hollandite. both the type of fe-oxide in soil and its degree of crystallinity may be regarded as indicators of the pedogenic environment because it seems to reflect the conditions under which they form (schwertmann & t a y l o r, 1989). consequently, they are sensitive to changing soil environment. this means that, for example, fe-oxides can be remobilized by reduction and again reoxidized in another favourable environment. the behaviour of manganese in soils also depends on changing soil environment. however, oxidized forms of manganese may be reduced to the mobile mn2 + at a higher eh than that at which fe3+ may be reduced to the more mobile fe2 + (fanning & fanning, 1989). namely, lovley (1995) stated that at ph 7 and 25°c reduction of mn4 + begins below a redox of 526 mv , while reduction of fe3+ starts at eh <-47 mv. according to lovley & phillips (1988) between the zone of mn reduction and that of fe reduction, there is little overlap because soil bacteria show an enzymatic preference for mn4 +, and fe3 + reduction will not begin until mn4+ is depleted. identification of fe oxides and especially mn oxides and hydroxides in soil by x-ray diffraction (xrd) may be complicated due to their small amounts, overlapping of diagnostic lines with those of associated minerals and the poor crystallinity of some phases. for identification and even quantification of secondary fe oxides in soils, several differential dissolution treatments can geologia croatica 54/1 27 36 11 figs. 2 tabs. zagreb 2001 key words: terra rossa, iron, manganese, iron oxides, istria, croatia. university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, hr-10000 zagreb, croatia. e-mail: gdurn@rudar.rgn.hr abstract haematite and goethite are the predominant pedogenic mineral phases in terra rossa from istria. limited variation of selected fe oxide characteristics in analysed samples indicates the specific pedogenic environment in which terra rossa is formed. the mean value of the fed/fet ratio, taken as an index of weathering is 0.7 and reflects quite a high degree of weathering of fe-containing primary silicates. relatively uniform fed/ clay ratios clearly indicate a predominance of coilluviation of clay and fe oxides. low values of feo point to the low content of poorly crystalline fe oxides in analysed terra rossa. f eo/f ed ratios in the analysed profiles vary. in the upper part of the pomer, poreë and novigrad profiles feo/f ed ratios are higher than in the lower part of those profiles which may be explained as a result of different pedogenic environments and/or additions of external materials in the upper part of those profiles. the lack of positive correlation between mnd and clay and mnd and fed is a consequence of remobilization of manganese due to hydromorphic processes which post-dated co-illuviation of clay and fe oxides. during the late tertiary and quaternary the pedogenic environment on hard carbonate rocks of the jurassic-cretaceous-palaeogene carbonate plain of southern and western istria generally remained suitable for rubification. however, (neo)tectonic activity and the input of external material, as well as various climatic fluctuations might have significantly effected terra rossa through the processes of erosion, colluviation, yellowing and secondary hydromorphy. 28 geologia croatica 54/1 be used. the most useful among them are an acid ammonium oxalate treatment and dithionite-citrate bicarbonate treatment. the former treatment extracts only poorly crystalline fe oxides, predominately ferrihydrite (schwertmann, 1964; schwertmann et al., 1982; schwertmann & taylor, 1989) , while the dithionite-citrate bicarbonate treatment (proposed by mehra & jackson, 1960) extracts practically all secondary fe oxides (schwertmann & taylor, 1989). acid ammonium oxalate extractable iron and manganese are usually labelled feo and mno while dithionite-citrate bicarbonate extractable iron and manganese are labelled fed and mnd. those parameters, when compared to total contents of given elements can be very helpful in understanding some aspects of the genesis of soils which contain iron oxides and manganese oxides and hydroxides such as red mediterranean soils which are situated on hard limestones and dolomites and are called terra rossa. for example, the occurrence and transformations of iron and manganese in a colluvial terra rossa toposequece of northern italy are excellently presented by boero & schwertmann (1987). the croatian soil classification puts terra rossa in the class of cambic soils (©kori∆, 1986). f.a.o. legends (fao, 1974) and soil taxonomy (soil survey staff, 1975) classify most of terra rossa as luvisols or alfisols. however, the problem of classification of red mediterranean soils is still open and controversial. namely, roquero (1993) insisted on a more accurate classification of red mediterranean soils while fedoroff (1997), recognised and proposed six different types of argillic horizons in these soils, based on abundance and morphology of textural features in the b horizons. racz (1999) proposed a new approach for the classification of terra rossa soils in croatia. the aim of this paper is to present data on the distribution of iron and manganese in terra rossa from istria and to evaluate any genetic implications. terra rossa is the most extensive soil type in istria. its diagnostic feature is a red colour (5yr to 10r munsell hues) and is the result of rubification, i.e. formation of haematite. terra rossa covers hard limestone and dolomite in the form of a discontinuous layer ranging in thickness from a few centimetres to several metres and is considered a polygenetic palaeosol or pedo-sedimentary colluvial fig. 1 distribution of terra rossa in istria (modified after ©kori∆, 1987). legend: 1) terra rossa, calcocambiosol, eutric cambiosol, rigosol from terra rossa (area of terra rossa >70%); 2) terra rossa, calcocambiosol, eutric cambiosol (area of terra rossa is 50-70%); 3) eutric cambisol on loess, luvisol on loess, rigosol from luvic and eutric cambiosol (40:30:30); (4) location of terra rossa samples. complex (durn, 1996; durn et al., 1999). durn et al. (1999) presented evidence for the polygenetic nature of terra rossa in istria, based on a detailed mineralogical and geochemical investigation. they concluded that both loess, older than that of the upper pleistocene age, and flysch might have contributed to the genesis of terra rossa. durn et al. (1999) also found that the arithmetic means of two populations (fed in 45 terra rossa samples from various locations around the world and f ed in 40 samples from istria) represent two independent estimates of the same population (fed in terra rossa) and concluded that this supports boero & schwertmann’s (1989) conclusion, that the rather limited extent of the variation of selected fe-oxide characteristics may indicate a specific pedogenic environment in which terra rossa is formed. in this paper terra rossa refers to reddish soils (5yr to 10r dry munsell colours) overlying hard and permeable limestone and dolomite. 2. study area the istrian peninsula belongs to the nw part of the adriatic carbonate platform and is composed of upper jurassic and cretaceous shallow water carbonate-rocks, palaeogene carbonate and clastic rocks, and neogene and quaternary sediments. the jurassic-cretaceouspalaeogene carbonate plain of southern and western istria, cretaceous-palaeogene carbonate-clastic zone characterised by overthrusting structures in eastern and north-eastern istria, and the palaeogene flysch basin of central istria are three main regions in istria from the geological point of view (veli∆ et al., 1995). istria is an example of a non-isolated karst terrain which was effected by karst processes, (neo)tectonic activity and input of external material since the late tertiary (durn et al., 1999). the most important external material was loess, the deposition of which, according to cremaschi (1990), has affected istria and the dalmatian archipelago since the early middle pleistocene. terra rossa is dominantly situated on the jurassiccretaceous-palaeogene carbonate plain of southern and western istria (fig. 1) in the form of a discontinuous surface layer up to 2.5 metres thick or the infill of cracks and sinkholes. pedo-sedimentary colluvial complexes which are found in karst depressions and are up to 14 metres thick also contain terra rossa like material (durn 1996; durn et al., 1999). 3. materials and methods terra rossa samples from b horizons on limestone and dolomite of jurassic and cretaceous age were sampled. forty samples were taken at 14 localities. particle size analysis was determined on the <2 mm fraction after dispersion in water and treatment with ultrasound. selected fractions were obtained using wet sieving and quantitative separation by sedimentation in cylinders after the appropriate settling time. total iron (fet) and manganese (mnt) were measured in <2 mm fraction of terra rossa samples with an xrf spectrometer (philips pw 1404) using pressed powder pellets. iron and manganese extractable with na dithionite-citrate bicarbonate (fed, m nd) were obtained after the method of mehra & jackson (1960) modified after u. schwertmann (pers. comm.), and measured with aas (pye-unicam sp9). iron and manganese extractable with ammonium oxalate (feo, m no) were acquired according to schwertmann (1964) and measured with aas (pye-unicam sp9). the iron oxide mineralogy of the clay fraction (<2 µm) of terra rossa was determined by x-ray powder diffraction (xrd) using a philips diffractometer (graphite monochromator, cukα radiation, proportional counter). xrd patterns of non-oriented samples were taken after the following treatments: (a) air-drying and (b) dissolution in hcl (1:1). 4. results 4.1. mineralogy xrd analysis showed that the clay fraction of all terra rossa samples from istria contains both haematite and goethite (fig. 2). broadening of diagnostic haematite and goethite xrd peaks indicates a low degree of crystallinity and their pedogenic origin. munsell hue of dry terra rossa samples ranges between 5yr and 10r (table 1) which indicates that red haematite masks the yellow colour of goethite. ferrihydrite (which also gives a red colour to soil) and mn-oxides or hydroxides were not detected by xrd, probably due to their small amounts and poor crystallinity. 29durn, slovenec & »oviê: distribution of iron and manganese in terra rossa... fig. 2 characteristic parts of xrd patterns of terra rossa sample 1 (<2 µm fraction). legend: a) air dried; b) treated with hcl (1:1, 24 h); kl kaolinite; i illitic material; q quartz; h haematite; g goethite. 30 geologia croatica 54/1 schwertmann & taylor (1989) stated that synthetic haematite crystals produced from ferrihydrite at near-pedogenic conditions generally exhibit a hexagonal morphology. estimated crystal size of haematite from the xrd and tem data according to the same authors is 20-50 nm in width and 10-20 nm in thickness. according to torrent & schwertmann (1987) with the increased size of haematite crystals the colour changes from red to purple. in order to establish the colour of haematite in relation to the size of haemasam. depth color clay* silt* sand* fe t* fed* feo fet/ feo/ fed/ mn t mnd mno mnd/ mno/ (cm) fed* fed clay mn t mnd profile sjenokoπa 1. 20-35 5yr4/8 41.1 58.3 0.6 4.20 2.78 0.39 0.66 0.14 0.068 1037 909 606 0.88 0.67 2. 35-100 5yr5/6 47.5 51.2 1.4 4.44 2.96 0.39 0.67 0.13 0.062 937 821 646 0.88 0.79 3. 100-145 5yr5/6 49.4 49.1 1.5 4.60 2.89 0.37 0.63 0.13 0.059 999 805 518 0.81 0.64 4. 145-200 5yr5/6 51.8 46.0 2.2 4.68 2.84 0.36 0.61 0.13 0.055 1192 558 330 0.47 0.59 5. 200-225 5yr5/6 54.2 45.3 0.5 5.12 3.22 0.44 0.63 0.14 0.059 1015 1000 839 0.99 0.84 6. 225-265 5yr5/6 53.0 46.1 0.9 4.90 3.34 0.53 0.68 0.16 0.063 984 969 694 0.98 0.72 7. 265-300 5yr5/6 57.1 42.6 0.2 5.29 3.22 0.40 0.61 0.12 0.056 883 800 555 0.91 0.69 8. 300-325 5yr4/6 61.1 38.6 0.3 5.75 3.78 0.60 0.66 0.16 0.062 1185 1100 1093 0.93 0.99 9. 325-335 5yr4/6 59.8 40.1 0.1 5.45 3.80 0.56 0.70 0.15 0.064 875 667 428 0.76 0.64 10. 335-360 5yr4/6 71.7 28.3 0.1 5.92 3.57 0.39 0.60 0.11 0.050 976 494 303 0.51 0.61 11. 360-400 5yr5/6 59.9 39.8 0.3 4.91 3.43 0.48 0.70 0.14 0.057 782 484 302 0.62 0.62 12. 400-450 2.5yr4/6 60.1 39.4 0.4 4.97 3.94 0.62 0.79 0.16 0.066 1084 1020 909 0.94 0.89 13. 450-550 2.5yr4/6 63.1 36.4 0.5 5.22 3.39 0.36 0.65 0.11 0.054 1200 391 251 0.33 0.64 14. 550-650 2.5yr4/6 64.6 34.8 0.6 5.51 3.79 0.31 0.69 0.08 0.059 1386 1173 933 0.85 0.80 15. 650-750 2.5yr5/8 66.4 32.7 0.9 5.51 3.96 0.30 0.72 0.08 0.060 1348 1127 909 0.84 0.81 16. 750-850 2.5yr4/6 62.9 36.2 0.8 5.41 4.00 0.28 0.74 0.07 0.064 1348 1255 1052 0.93 0.84 profile kamnik 19. 10-25 5yr4/6 32.5 65.1 2.4 3.37 1.86 0.29 0.55 0.16 0.057 930 614 532 0.66 0.87 19a 25-50 5yr4/6 35.7 61.9 2.4 3.40 2.03 0.30 0.60 0.15 0.057 852 523 513 0.61 0.98 profile pomer 22. 18-30 5yr5/6 45.1 52.7 2.2 3.74 2.42 0.31 0.65 0.13 0.054 1084 733 655 0.68 0.85 23. 30-62 2.5yr4/8 64.2 34.0 1.9 6.20 4.15 0.47 0.67 0.11 0.065 1084 782 626 0.72 0.80 24. 62-105 2.5yr4/8 71.1 28.0 0.9 6.03 4.11 0.37 0.68 0.09 0.058 1084 817 661 0.75 0.81 25. 105-130 10r4/8 70.2 28.7 1.1 5.60 3.91 0.38 0.70 0.10 0.056 930 662 512 0.71 0.77 profile poreë 53. 15-35 5yr4/6 59.4 39.5 1.1 6.10 4.01 0.46 0.66 0.12 0.054 1240 1093 741 0.88 0.68 55. 35-50 2.5yr5/6 74.1 25.2 0.8 4.70 3.19 0.36 0.68 0.11 0.054 1007 714 490 0.71 0.69 profile mondolaco 60. 12-30 2.5yr5/6 61.3 36.0 2.7 6.57 5.20 0.35 0.79 0.07 0.085 930 897 630 0.96 0.70 61. 30-60 2.5yr5/6 67.7 30.8 1.5 6.70 5.11 0.30 0.76 0.06 0.075 1782 1596 1072 0.90 0.67 profile novigrad 131. 9-20 5yr4/6 55.7 43.2 1.1 4.04 3.19 0.46 0.79 0.14 0.057 1471 956 773 0.65 0.81 132. 20-42 5yr4/6 60.3 38.6 1.2 412 3.64 0.36 0.88 0.10 0.060 1394 946 760 0.68 0.80 133. 42-63 2.5yr4/6 70.1 29.0 1.0 6.07 4.61 0.34 0.76 0.07 0.066 775 543 337 0.70 0.62 134. 63-80 2.5yr4/6 73.1 26.0 0.9 6.12 4.62 0.37 0.75 0.08 0.063 775 676 446 0.87 0.66 135. 80-112 2.5yr4/6 73.5 25.4 1.1 6.20 4.71 0.30 0.76 0.06 0.064 620 395 202 0.64 0.51 136. 112-150 2.5yr4/6 77.2 21.9 0.9 6.51 4.90 0.36 0.75 0.07 0.063 775 477 308 0.62 0.65 single samples 42. 5-15 5yr5/6 46.8 47.9 5.3 4.06 2.67 0.52 0.66 0.20 0.057 2401 1956 1900 0.81 0.97 52. 10-30 2.5yr4/8 42.1 55.3 2.5 5.47 3.76 0.30 0.69 0.08 0.089 387 287 87 0.74 0.30 100. 10-25 2.5yr4/8 72.1 26.8 1.1 6.67 5.24 0,47 0.79 0.09 0.073 620 326 275 0.53 0.84 101. 10-25 2.5yr5/8 73.8 25.4 0.8 7.06 5.74 0,48 0.81 0.08 0.078 779 394 201 0.51 0.51 234. 5-15 5yr4/8 35.8 61.1 3.1 3.38 2.30 0.25 0.68 0.11 0.080 1007 749 656 0.74 0.88 235. 5-10 2.5yr4/6 35.1 63.9 1.0 4.13 3.53 0.32 0.85 0.09 0.101 2169 1495 1252 0.69 0.84 236. 5-10 2.5yr4/6 42.1 57.3 0.6 4.33 3.31 0.36 0.76 0.11 0.079 1162 757 549 0.65 0.73 237. 5-10 2.5yr4/6 59.1 40.4 0.5 5.45 3.99 0.36 0.73 0.09 0.068 1084 730 463 0.67 0.63 table 1 particle size analysis, total, dithionite and oxalate extractable iron (%) and manganese (ppm) in terra rossa samples (<2 mm). color (dry) after munsell soil color charts (1994). clay (<2 µm), silt (2-63 µm) and sand (>63 µm); * data from durn et al. (1999). 31durn, slovenec & »oviê: distribution of iron and manganese in terra rossa... tite crystals, we prepared several samples of haematite by heating (for 1 hour) fine grained goethite at following temperatures: 300°, 500°, 700°, 900°, 1000° and 1300°c. with the increased temperature of heating, the size of haematite crystals also increased, which resulted in smaller broadening of xrd lines in relation to the instrumental broadening. the profiles of the 110 line at θ ≈1 7 .9° for haematite samples prepared at 300° and 1300°c are shown in fig. 3. the size of haematite crystals in direction <1 10> was determined from broadening of the 110 line after correction for instrumental broadening. the 110 line of haematite prepared at 1 3 00°c was used as a measure for instrumental broadening. the size of haematite crystals prepared at 300° , 5 00° and 700°c is about 21, 22 and 28 nm respectively, and their colour (powder) is red (10r4/8). the size of crystals prepared at 900°c is about 45 nm and they are dark red in colour (10r3/6). after heating to 1 0 00°c, crystal size increased to about 75 nm and colour changed to dusky red (10r3/4). the colour of a sample prepared at 1300°c is purple-red (no matching colour with munsell soil colour charts). we also prepared two homogeneous mixtures with a powder of kaolinite (33 wt.%), mica (30 wt.%), glass (20 wt.% ) , quartz (5 wt.%), goethite (6 wt.%) and haematite (6 w t.%). mixture 1 contained haematite prepared at 300°c while mixture 2 contained haematite prepared at 1 0 00°c. both mixtures matched the average composition of terra rossa clay fraction with two exceptions. the clay fraction of natural terra rossa contains illitic material and amorphous inorganic compound instead of mica and glass. the colour of the clay fraction of natural terra rossa is almost identical to the colour of mixture 1 which contain haematite prepared at 300°c. this matching of colour and broadening of 110 line at θ ≈1 7 .9° (fig. 2) clearly indicate that the size of haematite crystals in analysed terra rossa samples is lower than 50 nm which is in accordance with investigation of boero & schwertmann (1989). 4.2. total, na dithionite-citrate bicarbonate and ammonium oxalate extractable iron and manganese the results of the analysis of total, na dithionite-citrate bicarbonate and ammonium oxalate extractable iron and manganese are presented in table 1. mean values f et, fed and feo are 5.19 %, 3.68 % and 0.39 % respectively (table 2). the mean value of the fed/ f et r a t i o , which is taken as an index of weathering (e.g. arduino et al., 1984; boero & schwertmann, 1987; bech et al., 1997) is 0.7 and reflects quite a high degree of weathering of fe-containing primary silicates. relatively uniform fed/f et ratios in the analysed profiles (table 1) are also shown by the high positive correlation coefficient (fig. 4) and point to a clear relationship between fed andfet in terra rossa. the clay content in analysed terra rossa samples increases with depth in the profiles (table 1). an exception is the sjenokoπa profile, a colluvial terra rossa complex composed of superimposed features of colluviation and pedogenesis, where the clay content increases with depth within the each superimposed cycle (durn, 1996; durn et al., 1999). fed/clay ratios are relatively uniform (table 1, fig. 5) and clearly indicate a predomfig. 3 the profiles of the 110 line of haematite prepared by heating of goethite at 300° and 1300°c. n x s cv (%) 0.95 c.i. fet* 40 5.19 0.99 19.07 4.88-5.51 fed* 40 3.68 0.89 24.18 3.40-3.96 feo 40 0.39 0.09 23.08 0.36-0.42 fed/fet* 40 0.70 0.07 10.00 0.68-0.72 feo/fed 40 0.112 0.033 29.46 0.102-0.122 mnt 40 1089 379 34.80 968-1210 mnd 40 817 353 43.21 704-930 mno 40 625 341 54.56 516-734 mnd/mnt 40 0.74 0.15 20.27 0.69-0.79 mno/mnd 40 0.73 0.14 19.18 0.685-0.775 table 2 basic statistics for total, dithionite and oxalate extractable iron (%) and manganese (ppm) in terra rossa samples (<2 mm). legend: n) number of samples; x) arithmetic mean; s) standard deviation; cv) coefficient of variation (%); 0.95 c.i.) confidence interval. * data from durn et al. (1999). 32 geologia croatica 54/1 fig. 4 ratio between dithionite soluble iron (fed) and total iron ( f et) in terra rossa; r is significant at level p<0.01. fig. 6 ratio between oxalate extractable iron (feo) and dithionite extractable iron (fe d) of terra rossa samples; r is not significant at the level p<0.01. fig. 5 ratio between the amount of clay fraction (<2 µm) and dithionite soluble iron (fed) in terra rossa; r is significant at level p<0.01. 33durn, slovenec & »oviê: distribution of iron and manganese in terra rossa... inance of co-illuviation of clay and fe oxides, i.e. connection of fe oxides with the clay fraction. low values of feo (tables 1 and 2) point to the low content of poorly crystalline fe oxides in analysed terra rossa. feo/f ed ratios in the analysed profiles vary (table 1, fig. 6). in the upper part of the pomer, poreë and novigrad profiles (5yr munsell hues) feo/fed ratios are higher than in the lower part of those profiles (2.5yr and 10r munsell hues). significant positive correlation (r = 0.7) between feo and fed in samples with 5yr munsell hues was observed (fig. 7). mean values of mnt, mnd and mno are 1089 mg/kg, 817 mg/kg and 625 mg/kg respectively (table 2). the mean value of the mnd/m nt ratio is 0.74 and indicates that most of the manganese in terra rossa is in the form of mn oxides and hydroxides. a high positive correlation between mnd and mnt (fig. 8) points to a clear relationship between mnd a n dm nt in terra rossa. values of mno are lower compared to those of mnd (tables 1 and 2), and a high positive correlation between them (fig. 9) is in accordance with the results of blume & schwertmann (1969) who concluded that the presence of mn oxides and hydroxides in soil should be recognised on mnd values rather than on mno v a l u e s which does not provide any new qualitative information. consequently, in further texts only mnd v a l u e s will be evaluated. the lack of positive correlation between mnd and clay (fig. 10) and mnd and fed ( f i g . 11) show that mn oxides and hydroxides are not connected with the clay fraction and fe oxides. namely, they either do not participate in the co-illuviation of clay and fe oxides, or are remobilized later due to successive processes. 5. discussion and conclusion the association of haematite and goethite as predominantly pedogenic mineral phases, and the rather limited variation of selected fe oxide characteristics in terra fig. 7 ratio between oxalate extractable iron (feo) and dithionite extractable iron (fed) of 5yr terra rossa samples; r is significant at the level p<0.01. fig. 8 ratio between dithionite extractable manganese (mnd) and total manganese (mnt) of terra rossa samples; r is significant at the level p<0.01. 34 geologia croatica 54/1 rossa from istria, indicate specific pedogenic environment in which terra rossa is formed. our results match those of boero & schwertmann (1989) who concluded that this pedogenic environment is character ized by an association of a mediterranean climate, high internal drainage and neutral ph conditions. in the 30 samples examined (fraction < 2 µm) they also estimated that the haematite /(haematite+goethite) ratios averaged 0 . 62±0.055 i.e. the content of haematite is higher than the content of goethite in terra rossa. singer et al. (1998) interpreted the difference in iron oxide mineralogy between terra rossa (dominated by haematite) and rendzina (dominated by goethite) developed on limestones in israel as a consequence of soil climate, specifically the moisture regime of two soils. poorly crystalline fe oxides were not detected with xrd in analysed terra rossa. however, low values of f eo (tables 1 and 2) point to their very low (probably ferrihydrite) content. this was expected because most of the fe-oxides in fersialitic soils are crystallised (bech et al., 1997). relatively uniform fed/ clay ratios (table 1, fig. 5) clearly indicate a connection of fe oxides with the clay fraction, as iron oxides are translocated downwards together with clay illuviation. the main pedogenic process which characterises terra rossa in istria is the accumulation of clay and is manifested through: (1) clay illuviation in the form of coatings and/or (2) microaggregates incorporated in the groundmass due to argilloturbation and soil stress (du r n, 1996). according to fe d o r o f f (1997) rubification occurs in upper horizons, then rubified soil material is translocated with clays to depth. in general, the feo/fed ratio decreases with depth in the kamnik, pomer, poreë, mondolaco and novigrad profiles. a decrease of this ratio at depth in profiles was also observed by bech et al. (1997) in some red mediterranean soils from northern spain. significant positive correlation (r = 0.7) between feo and fed i n samples with 5yr munsell hues, and the higher content of feo in samples with 5yr munsell hues (0.137 % ) compared to samples with 2.5yr and 10r munsell fig. 9 ratio between oxalate extractable manganese (mno) and dithionite extractable manganese (mnd) of terra rossa samples; r is significant at the level p<0.01. fig. 10 ratio between the amount of clay fraction (<2 µm) and dithionite extractable manganese (mnd) of terra rossa samples; r is not significant at the level p<0.01. 35durn, slovenec & »oviê: distribution of iron and manganese in terra rossa... hues (0.089 %) may indicate a difference between those two groups of samples in respect to their pedogenic environment and/or parent material and, consequently, their content of poorly crystalline fe oxides. the difference in pedogenic environment can be explained with the higher content of organic material in the upper parts of analysed profiles. bech et al. (1997) concluded that there is a particular tendency for feo to correlate with organic matter content (r = 0.68). namely, organic matter in soil inhibits the crystallisation of fe oxides (blume & schwertmann, 1969). during recent or subrecent pedogenesis a yellowing process might have occurred by preferential dissolution of haematite due to the higher thermodynamic stability of goethite. according to boero & schwertmann ( 1 9 8 7 ) , during that process the goethite/haematite ratio increases, fed does not change significantly while feo m a y increase if inhibitors which prevent its transformation to more stable fe oxide phases are present. the presence of external materials in the upper parts of terra rossa profiles in istria was postulated by ©inkovec (1974) and ©k o r i ∆ (1979), and confirmed by durn (1996) and durn et al. (1999), who found low-charge vermiculite or high-charge smectite in the <0.2 µm fraction of terra rossa samples which are situated bellow or near upper pleistocene loess in savudrija. durn et al. (1999) concluded that the presence of this mineral in those samples may indicate its aeolian origin because it was detected as one of the main mineral phases in fine clay of the upper pleistocene loess in savudrija which post-dated terra rossa formation. they also discovered that both loess older than that of the upper pleistocene age and flysch might have contributed to the genesis of terra rossa. we interpret the lack of a positive correlation between mnd and clay (fig. 10) and mnd and fed ( f i g . 11) as a consequence of hydromorphic processes which post-dated co-illuviation of clay and fe oxides and resulted in the remobilization of manganese. during field work we observed the tendency of manganese oxides and hydroxides to concentrate as concretions and coatings on different soil features, mainly in the lower part of investigated profiles. istria is an example of a non-isolated karst terrain which was affected by karst processes, neotectonic activity and external material input since the late tertiary. although climatic and biotic factors have changed during the late tertiary and quaternary the pedogenic environment on the hard carbonate rocks of the jurassic-cretaceous-palaeogene carbonate plain of southern and western istria generally remained suitable for rubification (durn, 1996; durn et al., 1999). however, red mediterranean soils can be affected by eluviation, yellowing and secondary hydromorphy because they have been exposed to various climatic fluctuations (fedoroff, 1997). 6. references arduino, e., berberis, e., canaro, f. & forno, m.g. (1984): estimating relative ages from iron-oxide/total iron ratios of soils in the western po valley (italy).geoderma, 33, 39-52. bech, j., rustullet, j., garigó, j., tobías, f.j. & martínez, r. (1997): the iron content of some red mediterranean soils from northeast spain and its pedogenic significance.catena, 28, 211-229. blume, h.p. & schwertmann, v. (1969): genetic evaluation of profile distribution of al, fe and mn oxides.soil sci. soc. am. proc., 33, 438-444. boero, v. & schwertmann, u. (1987): occurrence and transformations of iron and manganese in a colluvial terra rossa toposequence of northern italy.catena, 14, 519-531. boero, v. & schwertmann, u. (1989): iron oxide mineralogy of terra rossa and its genetic implications.geoderma, 44, 319-327. cremaschi, m. (1990): the loess in northern and central italy: a loess basin between the alps and the mediterfig. 11 ratio between dithionite extractable manganese (mnd) and dithionite extractable iron ( f ed) of terra rossa samples; r is not significant at the level p<0.01. 36 geologia croatica 54/1 ranean regions.in: cremaschi, m. (ed.): the loess in northern and central italy. centro di studio per la stratigrafia e petrografia delle alpi centrali, editrice gutenberg, milano, 15-19. durn, g. (1996): origin, composition and genesis of terra rossa in istria.unpublished phd thesis (in croatian with english summary), university of zagreb, 204 p. durn, g., ottner, f. & slovenec, d. (1999): mineralogical and geochemical indicators of the polygenetic nature of terra rossa in istria, croatia.geoderma, 91, 125-150. fanning, d.s. & fanning, m.c.b. (1989): soil, morphology, genesis, and classification.john wiley & sons, new york, 395 p. fao (1974): soil map of the world, 1:5 m, volume 1, legend.unesco, paris. fedoroff, n. (1997): clay illuviation in red mediterranean soils.catena, 26, 171-189. lovley, d.r. & phillips, e.j.p. (1988): manganese inhibition of microbial iron reduction in anaerobic sediments.geomicrobiology jour., 6, 145-155. lovley, d.r. (1995): microbial reduction of iron, manganese, and other metals.advances in agronomy, 54, 175-231. mckenzie, r.m. (1989): manganese oxides and hydroxides.in: dixon, j.b. & weed, s.b. (eds.): minerals in soil environments.soil sci. soc. am., madison, 439465. mehra, o.p. & jackson, m.l. (1960): iron oxides removal from soils and clays by a dithionite-citrate-bicarbonate system buffered with sodium bicarbonate.7th nat. conf. clays clay miner., 7, 317-327. munsell soil color charts (1994): macbeth division of kollmorgem instruments corporation, new windsor. racz, z. (1999): current global and local issues and problems related to pedological research.agriculturae conpectus scientificus, 64/3, 231-241. roquero, c. (1993): some problems on genesis and classification of red soils in spain.second international meeting on “red mediterranean soils”. short papers and abstracts, adana, turkey, 8-10. schwertmann, u. (1964): differenzierung der eisenoxide des bodens durch photochemische extraktion mit saurer ammoniumoxalat-lösung.z. pflanzenernähr. bodenkund., 105, 194-202. schwertmann, u. & fanning, d.s. (1976): iron-manganese concretions in hydrosequences of soils in bavaria.soil sci. soc. am. j., 40, 731-738. schwertmann, u. & taylor, r.m. (1989): iron oxides.in: dixon, j.b. & weed, s.b. (eds.): minerals in soil environments. 2nd ed., soil sci. soc. am. book series, 379-438. schwertmann, u., murad, e. & schulze, d.g. (1982): is there holocene reddening (hematite formation) in soils of oxeric temperate areas?geoderma, 27, 209223. sidhu, p.s., sehgal, j.l., sinha, m.k. & randhawa, n.s. (1977): composition and mineralogy of iron-manganese concretions from some soils of the indogangetic plain in northwest india.geoderma, 18, 241249. singer, a., schwertmann, u. & friedl, j. (1998): iron oxide mineralogy of terre rosse and rendzinas in relation to their moisture and temperature regimes.eur. jour. of soil sci., 49, 385-395. soil survey staff (1975): soil taxonomy: a basic system of soil classification for making and interpreting soil surveys. usda handbook no. 436, u.s. gov. printing office, washington. ©inkovec, b. (1974): the origin of terra rossa in istria (in croatian).geoloπki vjesnik, 27, 227-237. ©kori∆, a. (1979): two-layer soil profile on the area of terra rossa in istria (in croatian).zemljiπte i biljka, 28, 111131, zagreb. ©kori∆, a. (1986): origin, development and systematics of soil (in croatian).spec. pub. of agricultural scientific meeting, zagreb, 172 p. ©kori∆, a. (1987): pedosphere of istria (in croatian).project council of pedological map of croatia, spec. ed., book 2, zagreb, 192 p. torrent, j. & schwertmann, u. (1987): influence of hematite on the colour of red beds.j. sedim. petrol., 57, 121-125. veli∆, i., ti©ljar, j., mati»ec, d. & vlahovi∆, i. (1995): a review of the geology of istria.in: vlahovi∆, i. & veli∆, i. (eds.): 1st croatian geological congress, excursion guide-book, 21-30, zagreb. manuscript received july 27, 2000. revised manuscript accepted april 23, 2001. 1. introduction the sample of algal limestone, containing, among other species, also numerous sections of the species described herein, had been collected more than 20 years ago by pavao mamuæiê and boπko korolija. they were involved in geological mapping of the area around primoπten and devoted their particular attention to upper cretaceous deposits. the first samples were collected from a partly investigated cross-section of platy limestones near the gas station at the entrance to primoπten. later the same locality was revisited and more samples collected, which contained enough sections for the new dasyclad species to be described, in addition to the earlier established uragiella matzi soka» & veli∆. salpingoporella donatae n.sp. (dasycladales) from upper cretaceous limestone of the environs of primoπten (dalmatia, croatia) branko soka» 2. systematic description order dasycladales tribe salpingoporellae bassoullet et al., 1979 genus salpingoporella pia, 1918 salpingoporella donatae n.sp. plates i-iii ?1995 salpingoporella ubaiydhi radoi»i∆.okla, p. 479, fig. 3/8. origin of name: the species is dedicated to the memory of the late donata nedéla-devidé who was the teacher of geological mapping for many generations of geology students at the faculty of science, university of zagreb. t y p e l o c a l i t y : outcrop of platy limestone in the road cutting near the gas station at the entry to primoπten, 43°35’17”n, 15°54’08”e (fig. 1). type stratum: very well-bedded, light brown to brown platy limestones, algal-peloidal packstone to grainstone, which, in addition to calcite cement, also contains some matrix recrystallized into microsparite. the sediment was deposited in a shallow subtidal low energy environment. a lower coniacian to campanian age is based on superposition. h o l o t y p e : tangential-longitudinal-oblique section figured in pl. i, fig. 2, in thin section labelled pr-791/37. paratypes are other, variously oriented, sections figured in pls. i-iii. the material is stored at the institute of geology in zagreb. d i a g n o s i s : the new species includes the general characteristics of the genus s a l p i n g o p o r e l l a . the species-specific feature is the wavy (humpy) shape of the primary branches, which are arranged in densely packed whorls. the branches are widened at their distal end and circular or slightly depressed in cross sections. dimensions in mm: see table 1. d e s c r i p t i o n : the alga has a slender, cylindrical skeleton with a comparatively narrow central cavity and occasionally a more or less curved thallus (pl. i, fig. 1; pl. ii, fig. 4). the inner surface (wall of the axial cavity) is even and uninterrupted, clearly and sharply deling eol. croat. 53/1 199 207 1 fig. 1 tab. 3 pls. zagreb 2000 key words: calcareous alga (dasycladales), upper cretaceous, dalmatia, croatia. institute of geology, sachsova 2, p.o.box 268, hr-10000 zagreb, croatia. abstract a new species of the dasyclad genus s a l p i n g o p o r e l l a , s. dona t a e, is characterized by wavy primary ramifications, which makes it easily distinguishable from other species of the genus. it derives from platy algal pelletal packstones and grainstones from the lower coniacian to campanian deposits of the environs of primoπten, dalmatia. uragiella matzi soka» & veli∆ has already been described from the same deposits. 200 geologia croatica 53/1 material (pl. ii, figs. 3-4) as a result of distally funnelshaped (widened) branches and the destruction of the outer surface. the inner cavity occupies, on average, 25-30% of the outer thallus diameter. simple primary branches are arranged in clearly defined and comparatively densely packed whorls. there are 14-18 branches per whorl, usually slightly inclined upwards (pl. i, figs. 2-3 and 8), though, in some specimens, branches may be inclined both upwards and downwards (pl. i, fig. 4). the most characteristic feature of the primary branches is their single or multiple bending resulting in their wavy shape (pl. i, figs. 2-3; pl. iii, fig. 12), or their changing diameter slight swellings and narrowings resulting in their humpy shape (pl. ii, fig. 5; pl. iii, figs. 10 and 13). in some specimens, the branches are in their proximal parts inclined downwards, whereas distally they are directed upwards, which gives them a knee-bend shape (pl. iii, fig. 11). some specimens show a slight swelling in the proximal part of branches, near to the wall of the axial cavity, which results in an elliptical or bladder-shaped widening, as shown in the sections illustrated in pl. iii, figs. 2, 4 and 11. in consecutive whorls, the branches are arranged in an alternating position, though such an arrangement in deeper tangential sections becomes less clear, due to dense packing, and appears irregular, so that only in shallow tangential (cortical) sections does the alternate arrangement becomes clear (pl. i, figs. 2, 4 and 6; pl. iii, figs. 1 and 6). at their distal ends, the branches are funnelshaped (phloiophorous branches) and often more or less vertically compressed, i.e. elongated along a plane perpendicular to the growth direction of the thallus. therefore, in vertical sections the pores appear circular (pl. i, figs. 1-2 and 6; pl. ii, figs. 5-7), or, if depressed, elliptical in outline (pl. iii, figs. 1 and 6-7). similarities and differences: s a l p i n g o p o r e l l a d o n a t a e n. sp. belongs to that group of the s a l p i n g o porella-species which is characterised by a narrow central cavity and more or less circular pores in tangential sections of their distal ends. s. adriatica (gu©i∆) also has a narrow central cavity and clearly phloiophorous branches (de castro & de rosa, 1977) but s . d o n a t a e is smaller and has more slender, more irreguholotype most frequent % maximum observed length of thallus l 10.70 5.00 _ outer diameter d 0.74-1.52 0.96 0.90-1.10 (60%) inner diameter d 0.17-0.34 0.22 0.20-0.30 (91%) d/d ratio 0.161-0.304 0.228 0.250-0.300 (56%) distance between whorls h 0.09-0.20 0.095 0.09-0.20 (72%) maximum diameter of branches p 0.06-0.14 0.08 0.08-0.10 (68%) length of branches l 0.21-0.51 0.46 0.35-0.45 (56%) number of branches per whorl w 14-18 table 1 dimensions of salpingoporella donatae n.sp. (in mm). measurements were made on 30 specimens. fig. 1 the type locality of salpingoporella donatae n.sp. eated, and perforated by entrance pores of the branches. the outer surface, originally probably smooth or even slightly bulging, becomes finely indented in fossil larly shaped and frequently upwards directed branches. s. pygmaea (gümbel) pia has about the same dimensions, but its branches gradually and uniformly widen from their proximal to their distal ends, whereas in s. donatae n.sp. the branches are wavy, more irregularly shaped, and funnel-shaped only at their distal ends. with regard to two small-sized species, s. istriana (gu©i∆) and s. johnsoni (dragastan), s. donatae n. sp. differs in having different values of individual parameters and differently shaped branches and in being somewhat larger (this being particularly clear with regard to s. johnsoni). similar differences also exist with regard to the equally small-sized s. verticilla t a (soka» & nikler), in which, however, the central cavity is somewhat wider and with an uneven wall and the branches are more steeply directed upwards and only distally inclined downwards. with regard to s . t u r g i d a (radoi»i∆), the new species is considerably smaller, has a narrower central cavity and, consequently, a different d/d ratio. the lower cretaceous s . p i r i n i a e karas & radoi»i∆, though being somewhat smaller, is visually similar but has differently shaped branches. the two species with a similar stratigraphic position, s. milovanovici radoi»i∆ and s . p o l s a k i soka» & jelaska are, in general, smaller and have differently shaped branches giving differently shaped pores in tangential sections. a more detailed comparison, however, with the contemporaneous s . ubaiydhi radoi»i∆ is needed. the latter is, indeed, 23 times smaller but has similar values of individual parameters (with a slightly larger d/d ratio). the most important difference between the two species concerns the shape of the branches, which, in s. ubaiydhi, have a short stalk and then widen uniformly or, sometimes, acquire a bellows-like shape (radoi»i∆, 1979, pl. i, figs. 3-4; pl. ii, figs. 1, 3), and are situated more or less perpendicular to the growth axis. moreover, in s. ubaiy dhi the branches in consecutive whorls are not arranged in an alternating position, which is clearly visible in outer tangential sections in s. donatae , particularly in specimens with elliptically elongated pores. another stratigraphically similar species, s. arumaensis o k l a , is considerably larger, has short, funnel-shaped and perpendicularly arranged branches as distinct from the longer, slimmer, and irregular branches in s. donatae and has a much broader central cavity which may occupy up to 50% of the outer diameter. other s a l p i n g o p o r e l l a -species may also show similar values of some parameters (see soka», 1996), but the main characteristic feature of s. donatae n. sp. wavy, irregular, and/or bent branches makes it clearly distinguishable from all other salpingoporella -species. stratigraphic position: salpingoporella donatae n. sp. was first observed, in a smaller number of sections, in the same sample which yielded the earlier described uragiella matzi soka» & veli∆, for which the stratigraphic position was stated as upper turoni an -lower coniacian. in the samples from the investigated locality no significant fossils have been found, and consequently their stratigraphic position is based on superposition. repeated collecting at the same outcrop yielded numerous sections of s. donatae ( w h i c h enabled the above description), accompanied also by not so abundant sections of s. ubaiydhi. this allows for a possibly broader stratigraphic range than previously considered. in the original description of s. ubaiydhi, radoi»i∆ (1979) reports its finding from the bottom of the well, from an interval for which a campanian, possibly uppermost santonian, age has been ascribed. in the text of the more detailed description of the well stratigraphy, for the lower part kh-1/7 it is said that it is represented by sediments of partly santonian? and also possibly coniacian age, lying at the top of the formation that may be of upper turonian and coniacian age. okla (1995), in the description of s. arumaensis , also gives some illustrations of s. ubaiydhi ( o k l a , 1995, figs. 3/7-3/9), among which there is one section (okla, 1995, fig. 3/8) which possibly belongs to s . d o n a t a e . it should be mentioned, admittedly, that the section in question is not completely clear, but it nevertheless shows some obvious differences with regard to the remaining two sections labelled s. ubaiydhi. the occurrence of s. ubaiydhi associated with s. donatae and uragiella matzi at the primoπten locality and the joint occurrence of s. ubaiydhi, s. arumaensis and possibly s. donatae at the top of the hajajok member (part of the azuma formation, central saudi arabia), to which the range campanian -maastrichtian is ascribed, suggests a broader range of their occurrence, covering a coniacian lower maastrichtian time span. acknowledgements i am grateful to my colleagues pavao mamuæi∆ and boπko korolija, who placed their samples at my disposal and thus initiated further research of the primoπten algal assemblage. i am also grateful to my co-worker of longstanding and co-author of the first paper on those algae, ivo veli∆, who later collected more samples and thus enabled the present study. finally, i am grateful to the reviewers, ivan gu©i∆, felix schlagintweit and jean-pierre masse, who gave useful suggestions that improved the present paper. 3. references bassoullet, j.p., bernier, p., conrad, m.a., deloffre, r. & jaffrezo, m. (1978): les algues dasycladacées du jurassique et du crétacé.géobios, mém. spéc., 2, 1-330, villeurbanne. de castro, p. & de rosa, c. (1977): osservazioni su salpingoporella adriatica (gu©i∆, 1966).boll. soc. natur. napoli, 86 (1977), 39 p., napoli. 201sokaë: salpingoporella donatae n.sp. (dasycladales) from upper cretaceous... 202 geologia croatica 53/1 dragastan, o. (1971): new algae in the jurassic and lower cretaceous in the bicaz valley (east carpathians) romania.rev. espan. micropal., 3, 155-192. gu©i∆, i. (1966): two new dasyclad species of the subgenus p i a n e l l a from lower cretaceous of istria.geol. vjesnik, 19, 35-46. karas, n. & radoi»i∆, r. (1991): salpingoporella p i r i n i a e n. sp. iz barema karbonatne platforme parnasa (kontinentalna grëka).geol. an. balk. poluost., 55/1, 163-173, beograd. okla, m.s. (1995): late cretaceous dasycladales from the aruma formation in central saudi arabia.n. jb. geol. paläont. mh., 1995, h. 8, 475-487, stuttgart. radoi»i∆, r. (1965): pianella turgida n.sp. from the cenomanian of the outer dinarids.geol. vjesnik, 18, 195-199, zagreb. radoi»i∆, r. (1978): salpingoporella milovanovici n.sp. a new dasyclad from the cenomanian strata of the dinarides and a note on the foraminifer n u m moloculina sp. (aff. regularis philippson).geol. an. balk. poluost., 42, 375-381, beograd. radoi»i∆, r. (1979): salpingoporella ubaiydhi , a new senonian dasyclad and some data about subsurface biostratigraphy of the western iraqi desert.bulletin acad. serbe sci. arts, classe sci. mathémat. natur., 68/19, 97-105, beograd. soka», b. (1996): taxonomic review of some barremian and aptian calcareous algae (dasycladales) from the dinaric and adriatic karst regions of croatia.geol. croatica, 49/1, 1-79, zagreb. soka», b. & jelaska, v. (1991): s a l p i n g o p o r e l l a p o l s a k i n. sp. (calcareous algae, dasycladaceae) from the cenomanian deposits of the island of braë.geol. vjesnik, 44, 1-7, zagreb. soka», b. & nikler, l. (1973): calcareous algae from the lower cretaceous of the environs of nikπiê, crna gora (montenegro).palaeont. jugoslav., 13, 57 p., zagreb. soka», b. & veli∆, i. (1983): uragiella matzi n.sp. (dasycladaceae) from the upper cretaceous of primoπten.geol. vjesnik, 36, 91-94. manuscript received november 29, 1999. revised manuscript accepted may 19, 2000. plate i 1-9 salpingoporella donatae n.sp. 1 oblique-tangential section, slide pr-79-1/70, x17. 2 tangential-oblique section, holotype, slide pr-79-1/37, x22. 3 oblique section, slide pr-79-1/27, x22. 4 oblique section, slide pr-79-1/36, x22. 5 tangential-longitudinal -section, slide pr-79-1/24, x22. 6 oblique section, slide pr-79-1/34, x22. 7 cross section, slide pr-79-1/33, x22. 8 oblique section, slide pr-79-1/40, x14. 9 tangential-slightly oblique section, slide pr-79-1/30, x22. age and location: lower coniacian campanian, primoπten (dalmatia, croatia). 203sokaë plate i 204 geologia croatica 53/1 plate ii 1-10 salpingoporella donatae n.sp. 1 oblique and cross sections, slide pr-79-1, x17. 2 oblique sections, slide pr-79-1/62, x22. 3 oblique sections, slide pr-79-1/48, x22. 4 tangential-oblique section, slide pr-79-1/20, x17. 5-7 oblique sections, fig. 5, slide pr-79-1/40; fig. 6, slide pr-79-1/71; fig. 7, slide pr-79-1/14, x22. 8-10 cross sections, fig. 8, slide pr-79-1/45; fig. 9, slide pr-79-1/41; fig. 10, slide pr-79-1/29, x22. age and location: lower coniacian campanian, primoπten (dalmatia, croatia). 205sokaë plate ii 206 geologia croatica 53/1 plate iii 1-16 salpingoporella donatae n.sp. 1-12 oblique sections, fig. 1, slide pr-79-1/69, x22; fig. 2, slide pr-79-1/31, x17; fig. 3, slide pr-79-1/14, x22; fig. 4, slide pr-79-1/67, x22; fig. 5, slide pr-79-1/39, x22; fig. 6, slide pr-79-1/67, x22; fig. 7, slide pr79-1/49, x22; fig. 8, slide pr-79-1/35, x22; fig. 9, slide pr-79-1/18, x22; fig. 10, slide pr-79-1/21, x22; fig. 11, slide pr-79-1/21, x22; fig. 12, slide pr-79-1/34, x22. 13-14 cross, slightly oblique sections, fig. 13, slide pr-79-1/11, x22; fig. 14, slide pr-79-1/27, x22. 15-16 cross sections, fig. 15, slide pr-79-1/55, x22; fig. 16, slide pr-79-1/17, x22. age and location: lower coniacian campanian, primoπten (dalmatia, croatia). 207sokaë plate iii 208 geologia croatica 53/1 geo.cro.2-3-61-kb.pdf 321 � vlasta ćosović1, katica drobne2, bojan ogorelec3, alan moro1, mladen koić1, ivan šoštarko1, alceo tarlao4 and giorgio tunis5 ab stra ct the renewed deposition in the palaeogene and the oldest part of the non-interrupted palaeocene succession is characterized by the presence of decastronema barattoloi (de castro), cyanobacterial tubes originally described in the apennines. the reinterpretation of limestones from several sections located in the kras region (nw part of the adcp: basovizza, dolenja vas, sopada, čebulovica) confi rmed the presence of these microfossils in peritidal sediments of danian age (sbz 1). the cuisian (late lower eocene) sediments, from eastern istria (brnjci section), cres island (koromačna cove section) and ravni kotari (benkovac–korlat section) contain individuals of this species in great numbers. the cyanobacterial tubes are scattered in laminated, fi ne grained mudstones and wackestones, immediately above the cretaceous sediments (occasionally above bauxites or breccias). the decastronema-bearing sediments pass upward into the foraminiferal limestones of cuisian age (sbz 11, based on conical agglutinated foraminifera and alveolinids), allowing the age determination of the cyanobacterial remnants. the palaeocene specimens are minute (up to about 180 μm long), thick walled tubes that occur with the index fossil bangiana hanseni drobne. the eocene forms accompanied by ostracods, pelecypods, and miliolid and rotaliid foraminifera are segmented tubes, up to 400 mm long and usually thin walled. keywor ds: decastronema barattoloi, adriatic carbonate platform, palaeocene, eocene, peritidal environment 1 department of geology, faculty of science, university of zagreb, horvatovac 102 a, 10000 zagreb, croatia; (vcosovic@geol.pmf.hr) 2 palaeontological institute i. rakovec zrc sazu, novi trg 2, 1000 ljubljana, slovenia; (katica@zrc-sazu.si) 3 geological survey of slovenia, diminičeva 14, 1001 ljubljana, slovenia; (bojan.ogorelec@geo-zs.si) 4 museo paleontologico cittadino di monfalcone, via valentinis 134, 34134 monfalcone, italy; (alceota@virgilio.it) 5 dipartimento di scienze gelogiche, ambientali e marine, università di trieste, via weiss 2, 34127 trieste, italy; (tunis@units.it) decastronema barattoloi (de castro), characteristic fossil of the palaeocene and the eocene peritidal sediments from the adriatic carbonate platform geologia croatica 61/2–3 321–332 3 figs. 1 tab. 2 pls. zagreb 2008 geologia croaticageologia croatica � 1. introduction radoičić (1959) described minute cylindrical tubes from cretaceous sediments in the external dinarides and established the new species aeolisaccus kotori. since then, the number of publications interpreting mat-forming cyanobacteria has increased over the years. there have been discrepancies in their taxonomic identifi cation as microfossils as well as in determining the age of sediments containing them. the unique architecture of the microfossils as characteristic of cyanobacterial sheaths was recognized by de castro (1975). geologia croatica geologia croatica 61/2–3 322 later on, de castro (1989) described another species, a. barattoloi, smaller than a. kotori, from coniacian to santonian sediments of mt. mutria (apennines, central italy). using the high resolution of the sem, the extent to which the specimens have preserved their original architecture and investigation of their presumed modern counterparts among the abundant mat-forming species of scytonema from the intertidal fl ats of the bahama carbonate platform, golubic et al., (2006) transferred aeolisaccus to decastronema. from 2006 onwards those taxa recognized as cyanobacteria (i.e. a. kotori and a. barattoloi) are referred to the genus decastronema. studies of the middle eocene, shallow-marine platform sediments from the adriatic carbonate platform (adcp, sensu vlahović et al., 2005) in the early 1970s (bignot, 1972) identifi ed the presence of cylindrical tubes of cyanophyceans similar to the recent microcoleus. shortly after specimens of a. barattoloi were described in sediments of mt. mutria (de castro, 1989), this species was recognized in sediments from the central part of the adcp, (ravni kotari region, drobne et al., 1991; fig. 1). besides these occurrences, remnants of a. barattoloi have been disocvered in the palaeocene part of the maastrichtian to danian succession in the kras region, (colle de medea and dolenja vas), by barattolo (1998). by that time, more localities with sediments containing cyanobacterial tubes were recognized, including basovizza, sopada, and čebulovica, all of danian age. their age attribution (figs. 2, 3) is based on the presence of bangiana hanseni drobne (pl. i, figs. d, e; drobne et al., 2007). what emerged as a striking characteristic is the fact that these microfossils occur in sediments of shallow marine origin, according to allochems and textural and structural features of sediments. these sediments were the fi rst to be deposited after periods of emersion. in the light of these recent works, we analyzed sediments from the south-eastern istria bauxite cave (brnjci) for the fi rst time, together with sediments from previously studied (and published) sections from the nw part of the adcp and from its central part. we reinterpreted the age attribution of the sediments known from the literature (sections mali mlun, krpan and soldatići, from central and se istria; figs. 2, 3). biotic evolution in the adcp settings within the palaeocene and eocene time span will enrich the limited knowledge of the role of decastronema barattoloi in the stabilization of shallow marine environments and as a signal microfossil for the main transgressive cycles in the perimediterranean region. on the basis of the recent data, the goals of this research are to: 1) better defi ne the biostratigraphic role of decastronema barattoloi, 2) refi ne the knowledge of its role in the evolution of stressed settings. 2. geological setting and stratigraphy some of the questions regarding the development of the adriatic carbonate platform (adcp) concern the age and conditions of re-establishment of the marine regime after the senofi gu re 1: simplifi ed geological map of the palaeogene domains, remnants of the adriatic carbonate platform showing location of the regions considered in this paper, adapted from ćosović et al., (2008): 1) the kras region, 2) istria, 3) cres island (northern adriatic islands), 4) ravni kotari region. geologia croaticavlasta ćosović et al.: decastronema barattoloi (de castro), characteristic fossil of the palaeocene and the eocene peritidal sediments... 323 nian emersion. in addition, there has been no reconstruction of the palaeoenvironmental conditions where continuation of a marine regime occurred between the upper cretaceous and the palaeogene. within the region that now forms the external dinarides, (considered here as comprising italy, slovenia and croatia); a marine carbonate platform regime existed from the late triassic to the middle eocene, with several shorter or longer sedimentary breaks. the palaeogene marine shallowwater carbonates were deposited on a sedimentary ramp system which culminated in middle eocene fl ysch deposits. during the early palaeogene, the region comprised an elongated nw-se trending gulf located at the palaeolatitude of 32° n (meulenkamp et al., 2000). tectonically, this time interval is characterized by the development (palaeocene; ogorelec et al., 2001; zamagni et al., 2008) and migration of a foreland basin (eocene; ćosović et al., 2004; vlahović et al., 2005). alternatively, drobne and co-workers (drobne, 2003; drobne & ogorelec, 2006; drobne et al., 2008) defi ned a model where four biosedimentary zones (biosz1 – biosz4; fig. 2) followed stepwise, one after another, from the late cretaceous to middle eocene (lutetian/bartonian boundary). this was based on both herak’s (1999) tectonic interpretation of the dinarides (within the “geotectonic” unit adriaticum), and their own detailed lithoand biofacies studies of many sections in the kras region and istria. the transition between the well documented geological developments of the adcp in the cretaceous, into the relatively short-lasting platform history of the palaeogene, is still one of the most disputed events in the geologic history of the region. from the great number of published papers (from the late 19th century, e.g. stache 1889 to recent, e.g. drobne et al., 2007), it is known that in the nw part of the carbonate entity, (kras region in sw slovenia), continuous sedimentation in transitional environments occurred between the maastrichtian and palaeocene. the upper cretaceous rudist-bearing limestones are overlain by the liburnian formation (fig. 3). these brackish to shallow marine sediments of various facies characteristics and fossil assemblages underlie the eocene alveolina-nummulites limestone. the near continuous k/t successions are exposed in several sections, where the dolenja vas section is one of the most studied (drobne et al., 1988, 1989, 1995, 1996; drobne & ogorelec, 1991; jurkovšek et al., 1996; ogorelec et al., 1995, 2007). the basovizza, čebulovica and sopada sections (pug liese et al., 1995; jurkovšek et al., 1996; ogorelec et al., 2001; riccamboni, 2005; zamagni et al., 2008) are also stratigraphically and sedimentologically well documented. the re-studied sediments are packstones to wacke stones (recrystallized biomicrites) with dasycladaleans, charophyta and corals (turnšek & drobne 1998). foraminifera are scattered throughout the matrix and are presented by discorbids, miliolids and bangiana hanseni drobne (pl. i, fig. d), considered as index fossils for the danian (drobne et al., 2007). for the west part of the adriatic carbonate platform (extending from the istrian peninsula in the nw, to central dalmatia, including the northern adriatic island of cres), the period between the latest cretaceous to the early eocene was characterized by subaerial exposures and non-marine conditions. generally, the upper cretaceous and eocene deposits for this part of the carbonate entity, (fig. 3), reveal that the eocene deposits unconformably overlie the cretaceous sediments. they comprise two formations: the liburnian formation characterized by marginal marine, paralic and palustrine carbonates of early eocene age, and the alveolina-nummulites limestones with numerous tests of larger benthic foraminifera of ypresian (sbz 11/12) to early middle eocene (sbz 13/14), or to late middle lutetian, sbz 14 or even bartonian sbz 17/18 age (drobne, 1977; drobne et al. 1991; ćosović et al., 1994, 2004). furthermore, the beginning of the eocene transgression was almost simultaneous over the region and corresponds to a cuisian age (fig. 2). the studied level is composed of a micrite-supported variety of limestones (wackestones to packstones) where scattered miliolids and rotalia-like foraminifera, ostracods, and fragments of pelecypods occur. reworked microcodium occurs in packstones (brnjci section) representing subaerial exposure surfaces. the age attribution was assigned based on fossil content identifi ed from overlying sediments. 3. material and methods this paper presents microfossil data for two regions: kras and istria to central dalmatia (fig. 1). several sections (basovizza, sopada, dolenja vas and čebulovica), all of palaeocene age, are located in the kras region. the most recent overview fi gu re 2: model of successive biosedimentary zones (bios. z. 1 – bios. z. 4) from the late cretaceous to late middle eocene on the adriatic carbonate platform (drobne, 2003; drobne & ogorelec, 2006; drobne et al., 2008) with distribution of decastronema barattoloi (de castro). geologia croatica geologia croatica 61/2–3 324 on palaeontological and sedimentological descriptions of these sections is given in ogorelec et al. (2001) ogorelec et al. (2007) and tewari et al., (2007). the re-studied limestones were interpreted (ibid.) as having been deposited in low-energy, near-shore lagoonal environments based on sedimentary textures, structures (stromatolites, shrinking cracks, fl at pebble conglomerates, and microcodium aggregates), and remains of foraminifera and dasycladaceans. the limestones are of danian age (sbz 1; serra-kiel et al., 1998). in the present study, the istrian to central dalmatian region is represented by the eocene sections located in istria, cres island and ravni kotari (fig. 1). in se istria, the transgressive upper cretaceous–eocene succession can be observed in an abandoned brnjci bauxite cave located in the vicinity of labin. the 8.25 m thick section has been logged, sampled by tunis, tarlao, moro and ćosović in july 2006 and has still to be described with respect to the sedimentary structures, texture and biotic components. the preliminary biostratigraphic results reveal that due to superposition (no erosional or no-depositional marks) the cyanobacterial bearing sediments are of cuisian (sbz 11) age. this is confi rmed by the overlying alveolina – “complex” miliolid limestones with the age-diagnostic species alveolina axiampla boljunesis drobne and alveolina levantina hottinger. stratigraphic reinterpretation of cyanobacteria-bearing limestones in the mali mlun, krpan and soldatići sections (in central and se istria), originally investigated by bignot (1972), was done by k. drobne using the depicted microfossils. instead of being of lutetian age, the re-described level is considered, based on associated foraminifers (idem, p. 143; pl. 44, fi g. 2 and p. 161; pl. 43, fi g. 5; pl. 47, fi g.1; plate 46, fi g. 3), to be of cuisian age. the koromačna sediments (ćosović et al., 1994; koić et al., 1995), which overlie the upper cretaceous limestones, contain numerous micritic tubes referred to as remnants of cyanobacteria. the age determination is possible due to the presence of a. levantina, coskinolina liburnica stache and periloculina dalmatina drobne in the fi rst sample which indicates a cuisian (sbz 11) age. fi gu re 3: schematic stratigraphic columns of the palaeocene – early eocene sediments in the kras region (basovizza, dolenja vas, čebulovica and sopada sections), and cuisian sediments in se istria, cres island and ravni kotari area (brnjci, koromačna and benkovac – korlat sections) with distribution of decastronema barattoloi (de castro). sbz shallow benthic zones (sensu serra-kiel et al., 1998, luterbacher et al., 2004), after drobne et al., 1991; ćosović et al., 1994; koić et al., 1995 and ogorelec et al., 2007. geologia croaticavlasta ćosović et al.: decastronema barattoloi (de castro), characteristic fossil of the palaeocene and the eocene peritidal sediments... 325 oriented thin sections have recently been made from samples collected in the 1990s in order to identify foraminiferal species. clusters of aeolisaccus barattoloi have been described from laminated limestones, characterized by irregular birds-eye and stromatolitic fabrics with perna istriana stache, primitive agglutinated conical foraminifera, orbitoilitids, and a. decastroi scotto di carlo (important for age attribution), in the benkovac – korlat section (drobne et al., 1991, p. 59). these limestones were interpreted to be of cuisian age (sbz 11) based on alveolinids and associated larger foraminifera. thin sections prepared from mud-supported varieties of the sampled limestones were examined under optical microscope. samples from brnjci cave were polished and briefl y etched by hcl, dried, and studied using an sem – vega tescan ts5136mm (operating or beam accelerating voltage 20 kv and back scatter detector (bse)). 4. results and discussion several studies of the palaeogene shallow marine platform carbonates from the adcp show the presence of cylindrical micritic tubes identifi ed as a fossil counterpart of modern microcoleus (bignot, 1972). de castro (1989, p. 111) has described microfossils similar to aeolisaccus kotori radoičić from 20–80 cm thick, bedded sediments from mt. mutria (apennines), squeezed between underlying bauxites and overlying miocene beds. this form is smaller than those described from the cretaceous: tubes are 33 mm long, with an inner diameter of 9 to 29 mm and an outer diameter between 16–36 mm. he named the form as aeolisaccus barattoloi. 4. 1. biostratigraphic position: palaeocene the oldest limestones containing this type of microfossil are known from the k/t succession in the nw part of the adcp (from kras region in sw slovenia and ne italy; figs. 2, 3). barattolo (1998) identifi ed these microfossils as aeolisaccus barattoloi from the danian limestones (sbz 1) in the dolenja vas section and colle di medea. danian sediments from the closely spaced čebulovica and sopada sections (drob ne et al., 1995; ogorelec et al., 2001) also contain these microfossils. fragments of the cylindrical tubes are mainly observable in cross-sections as circles with thick walls (pl. i, figs. a, b, c, d; tab. 1), up to 35 mm in outer diameter (21±7 mm), with an inner diameter of 14–21 mm, and a cylinder length of up to 178 mm (ranging between 100 and 178 mm). they are randomly scattered within a micritic matrix. limestones from the dolenja vas section were deposited in shallow-marine peritidal environments, while sediments from čebulovica originated in a lagoon with variable salinity, (documented by the presence of charophycean specimens known as “lagynophora liburnica stache” sensu stache, 1889). this environmental type is considered as unstable, due to the possible variations in salinity, shallow depth and proximity to land. in such circumstances, opportunistic forms are the fi rst colonizers, pioneers that will eventually convert habitat into more suitable area for specialists. while today there is a general consensus as to rejection of the genus lagynophora (feist & grambast-fessard, 2005), its taxonomic status was previously highly acknowledged. 4.2. biostratigraphic position: eocene the second occurrence of decastronema barattoloi coincides with the presence of the cuisian (ypresian) sediments in southeastern istria (labin environment, bignot, 1972; brnjci section, this paper), in the northern adriatic island of cres (koromačna section; ćosović et al., 1994; koić et al., 1995) and in ravni kotari (benkovac – korlat section; drobne et al., 1991). interestingly, the cyanobacterial tubes occur within the oldest palaeogene sediments, those deposited immediately above the cretaceous deposits and thus representing the fi rst transgressive unit (figs. 2, 3). filaments of d. barattoloi in the brnjci section are dispersed as linear accumulations within the micritic matrix, (pl. ii, fig. a). the cylindrical tubes are disposed in such a way that their long axes are parallel one to another, suggesting that the fi laments were distributed in a way that resulted in more or less continuous coverage (matforming sheets). they appear as hollow tubes with an outer diameter of 32 to 42 mm (mean deviation of 5 mm), an inner diameter of 20 mm, and from 120 to 370 mm long (pl. ii, fig. c). in cross-section they are circular (pl. ii, figs. b, c), with outer diameters of 32 to 42 mm, while the inner diameter is about 20 mm (tab. 1). the associations of benthic foraminifera, (small thin shelled miliolids and discorbids), small ostracods with thin carapaces, and charophyte remains, together with the sedimentary texture and structures (thin bedded), all suggest deposition in a low-energy, restricted environment, probably in a brackish lagoon. the overlying sediments, rich in larger benthic foraminifera (orbitolitids, alveolinids, “complex” miliolids and conical agglutinated ones), suggest inner (lagoonal) shelf settings. in the koromačna section (cres island; pl. ii, fig. d), fi laments are cylindrical tubes up to 375 mm long, with an inner diameter of 53 mm and outer diameter of 80 mm. in the studied part of the benkovac – korlat section (drob ne et al., 1991, p. 59), the predominance of mud-supported lithologies, packstones with relatively abundant carbonate mud, and lack of wave-related fabrics, indicate that deposition occurred in a protected, shallow-marine setting. agglutinated foraminifera, alveolina, “complex” miliolids, and orbitolites thrived in a protected and vegetated inner shelf environment placed above the decastronema-bearing sediments. the tubules of decastronema remnants have an inner diameter of 36 mm ± 9 mm expressed as mean derivation (pl. ii, figs. e, f). the wall appears dark and thick in thin section, with an external diameter ranging from 45 to 64 mm. the segmented tubular hollows are 136–345 mm long (241 ± 105 mean deviation). the presence of decastronema barattoloi in sediments from the adcp coincides with the ilerdian/cuisian boundary (figs. 2, 3). this interval, although known from dramatic changes in the open marine biota, recently has been recognized in changes in shallow-water biota due to rising temperature and changes in the trophic resource regime. geologia croatica geologia croatica 61/2–3 326 plate i photomicrographs of decastronema barattoloi (de castro) and bangiana heneseni drobne of the danian (sbz 1) a, b recrystallized biomicrites, wackestones, basovizza section, sample rrb – b15. c recrystallized biomicrite, wackestone, sopada borehole s 37. d wackestone, dolenja vas section, sample dv w 1/6605. e metković-sjekoše section, sample me-sj 10/4-7429. figures a, b and c are taken from riccamboni, 2005 with his permission, and fi gures d, e from drobne et al., 2007. geologia croaticavlasta ćosović et al.: decastronema barattoloi (de castro), characteristic fossil of the palaeocene and the eocene peritidal sediments... 327 geologia croatica geologia croatica 61/2–3 328 plate ii photomicrographs of decastronema barattoloi (de castro) of cuisian (sbz 11) a, b, c brnjci section, sample br–10. d koromačna section, cres island, sample kor 2. e, f benkovac – korlat section, sample be–kor 6/ 5656. geologia croaticavlasta ćosović et al.: decastronema barattoloi (de castro), characteristic fossil of the palaeocene and the eocene peritidal sediments... 329 geologia croatica geologia croatica 61/2–3 330 4.3. sedimentary environments the palaeocene in the kras region is dominated by charophyta, rotaliid foraminifera (bangiana hanseni in particular; drobne et al., 2007, pl. i, fi g. d) and ostracods. the eocene sediments from istria, the northern adriatic islands and ravni kotari, contain in addition to cyanobacteria, rotaliid foraminifera, small miliolids, ostracods, and pelecypods in varying amounts. the presence of the cyanobacterial fi laments across the time interval suggest that their appearance is related to colonization of newly emergent marine environments. thus, decastronema specimens can be recognized as organism-pioneers. their role in populating environments is somehow controversial: they can operate as stabilizers providing an opportunity for other organisms to thrive, or they can prevent further diversifi cation of organisms. their abundance determines their role: if cyanobacteria are abundant (a condition known as “cyanobacterial proliferation”) they form surface cover mats (golubic et al., 2006), and inhibit the introduction of other organisms and further biodiversifi cation. if they are common, but not over expanded, they can be considered as organisms that change the environment in a manner that results in it being more hospitable by producing oxygen, and maintaining certain chemical properties and nutrient levels, all of which improve conditions for further colonization. in addition, sediments deposited under such conditions may have different taphonomic and diagenetic histories to sediments deposited in areas where cyanobacterial fi laments are absent, (some skeletal grains are under represented, and some are more deteriorated). scattered occurrences of microfossils from all studied sections favour the latter option. the widespread cyanobacterial remains are interpreted as a consequence of the increased concentration of nutrients. the intensive weathering on the land in the early palaeocene and early eocene brought terrigenous input into the coastal settings, provoking low-light conditions, and susceptibility to salinity variations. decastronema communities have benefi ted from all of these conditions. such ecological changes in the shallow-marine environments of the adcp were most probably linked with the palaeogeography of the area. the differences between palaeocene and eocene fi laments are summarized in table 1. the palaeocene forms are thick walled and smaller, up to ~180 mm long, hollowed tubes. the eocene tubes (even segmented) reach up to 400 mm in length with varying wall thickness between 10 to 20 mm. thus, decastronema barattoloi is a potentially useful paleoenvironmental indicator, and therefore, this review is partly intended to be used as a tool to aid the reconstruction of depositional environments. 5. conclusions the palaeocene (danian) and early eocene (cuisian) sediments from the external dinarides (kras region, istria, northern adriatic island, and ravni kotari) are characterized by the presence of cyanobacterial fi laments of decastronema barattoloi (de castro). the palaeocene specimens are minute (up to 180 mm), thick walled tubes that occur with the index fossil bangiana hanseni drobne. the eocene forms accompanied by ostracods, pelecypods, and miliolid and rotaliid foraminifera are segmented tubes, up to 400 mm long and usually thin walled. their abundance within laminated sediments, redefi ned the stratigraphic range of the genus decastronema from the cretaceous to the early eocene. these microfossils are common within shallow-marine platform, peritidal sediments in the perimediterranean region. their concentration has been interpreted as a result of unstable (severe) palaeoecological conditions which favour the development of cyanobacterial mats. nutrient enrichment favoured cyanobacterial distribution and generated the possibility to develop more diverse benthic assemblages in the subsequent evolutionary stages of the adriatic carbonate platform. acknowledgement we are grateful to the following for their help: željko ištuk (zagreb) and kata cvetko-barić (ljubljana) for preparation of thin sections, robert košćal for drawings, morana hernitz kučenjak for microphotos and hrvoje posilović for sem images. carrie schweitzer polished the english and signifi cant improved the text. thanks are due to rodolfo riccamboni for kindly provided permission to use table 1: size characteristics and age relationships of decastronema barattoloi (de castro), with textural features and biotic components. sections textures benthic foraminifera other biota age interpreted settings decastronema barattoloi: dimensions basovizza dolenja vas sopada čebulovica wackestones packstones bangiana hanseni drobne miliolids charophyta, ostracods, pelecypods danian sbz 1 inner most ramp, lagoons with restricted conditions length= 100–178 μm inner diameter= 14–21 μm outer diameter= 21–35 μm brnjci wackestones packstones miliolids rotaliids ostracods, pelecypods, microcodium sp. cuisian sbz 11 inner most ramp with restricted conditions length= 120–370 μm inner diameter= 20 μm outer diameter= 32–42 μm fučinska koromačno wackestones packstones rotaliids ostracods cuisian sbz 11 inner most ramp with restricted conditions length= 375 μm inner diameter= 53 μm outer diameter= 80 μm benkovac-korlat wackestones packstones miliolids rotaliids pelecypods cuisian sbz 11 inner most ramp with restricted conditions length= 136–345 μm inner diameter= 27–45 μm outer diameter= 45–64 μm geologia croaticavlasta ćosović et al.: decastronema barattoloi (de castro), characteristic fossil of the palaeocene and the eocene peritidal sediments... 331 microphotos of decastronema barattoloi (de castro) from the basovizza section and sopada borehole. filippo barattolo and nevio pugliese are thanked for critical reading the manuscript. this study was carried out within the project “terroir of sediments deposited between 108 and 35 ma in nw croatia” of croatian ministry of science, education and sports. the study is also a part of the unesco igcp projects (no. 286 and 393). references barattolo, f. (1998): dasycladacean green algae and microproblematica of the uppermost cretaceous – palaeocene in the karst area (ne italy and slovenia). – in: hottinger, l. & drobne, k. (eds.): palaeogene shallow benthos of the tethys. opera sazu, iv, 34/2, 65–128. bignot, g. (1972): recherche stratigraphiques sur les calcaires du crétacé supérieur et de l’eocène d’istrie et des regions voisine. essai de revision du liburnien. – trav. lab. micropaleontol., phd. thesis, univ. paris, vi/2, 1–353. ćosović, v., balončić, d., koić, m., marjanac, t., moro, a., gušić, i. & jelaska, v. (1994): palaeontological evidence of palaeogene transgression on adriatic carbonate platform. – géol. méditerran., 21/3–4, 49–53. ćosović, v., drobne, k. & moro, a. (2004): paleoenvironmental model for eocene foraminiferal limestones of the adriatic carbonate platform (istrian peninsula). – facies, 50, 61-75. ćosović, v., marjanac, t., drobne, k. & moro, a. (2008): outer dinarids – eastern adriatic coast. – in: mc cann, t. (ed.): palaeogene and neogene of central europe. – geological society, spec. publ., london, 1031–1039. de castro, p. (1975): osservazioni su aeolisaccus kotori radoičić 1959 (cyanoschizophyta). – boll. della soc. dei natur. in napoli, 84, 123. de castro, p. (1989): on some foraminifera and algae in apennine upper cretaceous and palaeocene. – mem. soc. geol. it., 40 (1987), 109–124. drobne, k. (1977): alveolines palaeogenes de la slovenie et de l’istrie. – schweitz paläontol. abh., 99, 1–132. drobne, k., ogorelec, b., pleničar, m., zucchi-stolfa, m.l. & turnšek, d. (1988): maastrichtian, danian and thanetian beds in dolenja vas (nw dinarides, yugoslavia) microfacies, foraminifers, rudists and corals. – razprave sazu, iv, 29, 147– 224. drobne, k., ogorelec, b., pleničar, m., barattolo, f., turnšek, d. & zucchi-stofa, m.l. (1989): the dolenja vas section, a transition from cretaceous to palaeocene in the nw dinarides, yugoslavia. – mem. soc. geol. it., 40 (1987), 73–84. drobne, k. & ogorelec, b. (1991): the section dolenja vas, upper maastrichtian, lower and upper danian, thanetian. – in: drobne, k. (ed.): introduction to the palaeogene sw slovenia and istria. field trip guidebook. 2nd meeting igcp 286 “early palaeogene benthos” (postojna 1991), 47–53, ljubljana. drobne, k., vlahović, i., trutin, m., pavlovec, r., ćosović, v., babac, d., cimerman, f., lučić, d. & pavšič, j.(1991): excursion b – ravni kotari. palaeogene. – in: vlahović, i. & velić, i. (eds): some aspect of the shallow water sedimentation on the adriatic carbonate platform (permian to eocene). excursion guide-book. 2nd intern. symposium on the adriatic carbonate platform. relations with adjacent regions (zadar, may 1991). instit. geol., zagreb, 56–104. drobne, k., ogorelec, b., barattolo, f., dolenec, t., pleničar, m., turnšek, d., zucchi-stolfa, m.l. & marton, e. (1995): stop 1: the dolenja vas section (upper maastrichtian, lower and upper danian, thanetian). – atti mus. geol. paleont. monfalcone. quaderno spec., 3, 99–115. drobne, k., ogorelec, b., dolenec, t., marton, e. & palinkaš, l.(1996): biota and abiota at the k/t boundary in the dolenja vas section, slovenia. – in: drobne, k., goričan, š. & kotnik, b. (eds): international workshop postojna ‘96: the role of impact processes in the geological and biological evolution of planet earth. zrc sazu, 163–181, ljubljana. drobne, k. (2003): palaeogene biota from the sedimentary zones 1–4 on the adriatic carbonate platform (acp). – in: vlahović, i. & tišljar, j. (eds): 22nd ias meeting of sedimentology (opatija – september 17–19, 2003), abstracts, 91–92, zagreb. drobne, k. & ogorelec, b. (2006): geologic overview of the palaeogene in sw slovenia. – in: melis, r., romano, r. & fonda, g. (eds): giornate di paleontologia 2006, guida alle escursioni. societa paleontologica italiana, atti, 37–42, trieste. drobne, k., ogorelec, b. & riccamboni, r. (2007): bangiana hanseni n. gen. n. sp. (foraminifera) an index fossils species of danian age (lower palaeocene) from the adriatic carbonate platform (sw slovenia, ne italy, herzegovina). – razprave iv. razreda sazu, 48/1, 5–71. drobne, k., ogorelec, b., pavšič, j. & pavlovec, r. (2008): slovenian tethys basins. – in: mc cann, t. (ed.): palaeogene and neogene of central europe. geological society, spec. publ., london, 1093–1098. dunham, j.b. (1962): classifi cation of carbonate rocks according to depositional texture. – in: ham, w.e. (ed.): classifi cation of carbonate rocks. amer. assoc. petro. geol. mem., 1, 108–121. feist, m.n. & grambast-fessard, n. (2005): nomina nuda and generic names wrongly attributed to charophyta. – in: feist, m.n. (ed.): treatise on vertebrate paleontology, part b, protista 1, vol. i, charophyta. geol. soc. america; university of kansas press, lawrence, 146–148. golubic, s., radoičić, r. & seong-joo, l. (2006): decastronema kotori gen.nov., comb. nov.: a mat-forming cyanobacterium on cretaceous carbonate platforms and its moderen counterparts. – carnet de géologie: article 2006/02 (cg2006_a02). herak, m. (1999): tectonic interpretatition of the dinarides and the southern alps. – geol. croat., 52/1, 83–98. jurkovšek, b., toman, m., ogorelec, b., šribar, l., drobne, k., poljak, m. & šribar, lj. (1996): formacijska geološka karta južnega dela tržaško-komenske planote 1:50 000 – kredne in paleogenske kamnine [formations geological map of the southern part of the trieste – komen plateau – cretaceous and palaeogene carbonare rocks – in slovenian]. iggg, 143, ljubljana. koić, m., ćosović, v., gušić, i., jelaska, v., marjanac, t. & moro, a. (1995): some palaeontological evidence of the palaeogene transgression on the adriatic carbonate platform. – in: vlahović, i., velić, i. & šparica, m. (eds): proceedings 1, 1st croatian geol. congress, opatija. inst. geol., zagreb, 293– 297. luterbacher, h.p., alin, j.r., brinkhuis, h., gradstein, f.m., hooker, j.j., monechi, s, ogg, j.g., powell, j., rohl, u., sanfilippo, a. & schmitz, b. (2004): the palaeogene period. – in: gradstein, f.m., ogg, j.g. & smith, j. (eds): a geologic time scale 2004. cambridge university press, 384–408. geologia croatica geologia croatica 61/2–3 332 meulenkamp, j.e., sissingh, w. & beniamovskii, v.n. (2000): map 17. early/middle ypresian. – in: dercourt, j., gaetani, m., vrielynck, b., barrier, e., biju-duval, b., brunet, m.f., cadet, j.p., crasquin, s. & sandulescu, m. (eds): atlas peri-tethys, palaeogeographic maps. comission de la carte géologique du monde, paris. ogorelec, b., dolenec, t., cucchi, f., giacomich, r., drob ne, k. & pugliese, n. (1995): sedimentological and geochemical characteristics of carbonate rocks from the k/t boundary to lower eocene in the karst area (nw adriatic platform). – in: vlahović, i., velić, i. & šparica, m. (eds): proceedings 2, 1st croatian geol. congress, opatija. inst. geol., zagreb, 415–421. ogorelec, b., drobne, k., jurkovšek, b., dolenec, t. & toman, m. (2001): palaeocene beds of the liburnian formation on čebulovica section (slovenia, nw adriatic – dinaric platform). – geologija, 44/1, 15–65. ogorelec, b., dolenec, t. & drobne, k. (2007): cretaceoustertiary boundary problem on shallow carbonate platform: carbon and oxygen excursions, biota and microfacies at the k/t boundary sections dolenja vas and sopada in sw slovenia, adria cp. – palaeogeogr., palaeoclimat., palaeoecol., 255/1–2, 64–76. pugliese, n., drobne, k., barattolo, f., caffau, m., galvani, r., kedves, m., montenegro, m.e., pirini-radrizzani, c., pleničar, m. & turnšek, d. (1995): microand macrofossils from k/t boundary through palaeocene in north ern adriatic platform. – in: vlahović, i., velić, i. & šparica, m. (eds): proceedings 2, 1st croatian geol. congress, opatija. inst. geol., zagreb, 505–513. radoičić, r. (1959): nekoliko problematičnih mikrofosila iz dinarske krede [some problematic microfossils from the dinarian cretaceous – in serbian]. – vesnik (a), 17, 87–92. riccamboni, r. (2005): evidenze del passagio cretacico – terziario nel carso triestino e sloveno. – tesi di laurea in paleontologia. universita degli studi di trieste, 206 p. serra-kiel, j., hottinger, l., caus, e., drobne, k., ferrandez, c., jauhri, a.k., less, g., pavlovec, r., pignatti, j., samso, j.m., schaub, h., sirel, e., strougo, a., tambareau, y., tosquella, j. & zakrevskaya, e. (1998): larger foraminiferal biostratigraphy of the tethyan palaeocene and eocene. – bull. soc. géol. france, 169, 281–299. stache, g. (1889): die liburnische stufe und deren grenzhorizonte. – abh. k.k. geol. r.a. wien, 13/1, 1–170. tewari, v.c., stenni, b., pugliese, n., drobne, k., riccamboni, r. &. dolenec, t. (2007): peritidal sedimentary depositional facies and carbon isotope variation across k/t boundary carbonates from nw adriatic platform. – palaeogeogr., palaeoclimatol., palaeoecol., 255, 77–86. turnšek, d. &. drobne, k. (1998): palaeocene corals from the northern adriatic platform. – in: hottinger, l. & drobne, k. (eds): palaeogene shallow benthos of the tethys. opera dela sazu, 34 /2, 129–154, ljubljana. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: paleogeography, main events and depositional dynamics. – palaeogeogr., palaeoclimat., palaeoecol., 220, 333–360. zamagni, j., mutti, m. & košir, a. (2008): evolution of shallow ben thic communities during the late palaeocene-earliest eocene transition in the northern tethys (sw slovenia). – facies, 54/1, 25–43. manuscript received february 5, 2008 revised manuscript accepted may 19, 2008 mrinjek et al.indd 1. introduction this paper is concerned with a middle member of the promina formation (known also as the promina beds) of northern dalmatia. the upper eocene benkovac stone member consists of thinly bedded, shallow-marine calciclastic deposits that crop out as a narrow, setrending belt near the town of benkovac (fig. 1). the component sedimentary facies of the benkovac stone member are described in detail and their genesis is discussed, which leads to an environmental model of a storm-dominated offshore transition zone. the palaeogeography, stratigraphic context and regional signifithe benkovac stone member of the promina formation: a late eocene succession of storm-dominated shelf deposits ervin mrinjek1, vili pencinger2, jasenka sremac1 and boris lukšić2 cance of this tempestitic succession are also discussed. the paper sheds new light on the origin of a little-studied part of the promina formation, and thus contributes to a better understanding of the latter. 2. stratigraphic setting and previous studies the promina formation is a succession of calciclastic deposits of late middle eocene to early oligocene age, approximately 2000 m thick, with a prominant shallowing-upward trend from deepto shallow-marine and alluvial facies. the benkovac stone member belongs to the transitional middle part of the promina formation, overlying its turbiditic lower part. the promina formation is the upper part of the extensive palaeogene clastic succession of northern dalmatia, overlying mesozoic to middle eocene platform carbonates. the promina formation overlies conform geologia croatica 58/2 163–184 29 figs. zagreb 2005 key words: shelf, shoreface, offshore transition zone, tempestites, hummocky cross-lamination, wave ripples, oscillatory waves, combined-flow currents, trace fossils, braidplain delta, sequence stratigraphy, northern dalmatia, croatia. 1 department of geology and palaeontology, faculty of science, university of zagreb, horvatovac 102a, hr-10000 zagreb, croatia; e-mail: ervin.mrinjek@zg.htnet.hr. 2 croatian geological survey, sachsova 2, hr-10000 zagreb, croatia. abstract the upper eocene benkovac stone member of the promina formation of northern dalmatia, croatia, is a thinly bedded succession of alternating carbonate sandstones and calcareous mudstones, ca. 40 m thick, exposed as a narrow, se-trending outcrop belt near the town of benkovac. this unit occurs in the middle part of the promina formation, which is a spectacular calciclastic succession of deposits of late middle eocene to early oligocene age, about 2000 m thick, showing an upward trasition from deep-marine turbidites to shallow-marine and alluvial deposits. the sheet-like sandstone beds of the benkovac stone member are mainly 1–25 cm thick and have been classified into 6 facies and 3 subfacies, differing in stratification or showing various internal sequences of stratification types. the thicker and most common beds show plane-parallel stratification passing upward into hummocky cross-lamination and undulatory to flat parallel lamination (facies s1), or consist of only the latter two divisions (facies s2). subordinate beds show convolute stratification (facies s3), are amalgamated (facies s4), or are homogenized and merely graded (facies s6). the thinner beds have more uneven boundaries and show translatory ripple cross-lamination (subfacies s5a), climbing ripple cross-lamination (subfacies s5b) or pinch-and-swell lamination attributed to starved and rolling-grain ripples (subfacies s5c). the intervening mudstone beds (facies m) are silt-streaked and bioturbated. trace fossils indicate a combination of zoophycos and cruziana ichnofacies. the sedimentary succession was deposited in a microtidal offshore transition zone characterized by muddy “background” sedimentation punctuated by discrete storm events. the observed spectrum of tempestite sandstone beds represents a wide range of storm events, varying in magnitude and in the mode of sand dispersal – from the pure action of oscillatory waves to pure geostrophic currents. the majority of tempestites are attributed to a combination of these two end-member factors, with the geostrophic currents often enhanced by a high load of sediment suspension (density-modified currents). the benkovac stone member is underlain by muddy offshore deposits (debelo brdo member) and covered by sandy to gravelly shoreface deposits (otavac member), which in turn pass upwards into braidplain deltaic and alluvial deposits. this regressive succession is considered to be a parasequence deposited as a highstand systems tract during a gradual, stepwise rise of relative sea level. the thick parasequence consists of progradational and retrogradational sets of much smaller parasequences, the record of which differs markedly in the shoreface and offshore transitional part. the difference is attributed to the underlying contrast in the physical factors controlling the supply of sand to these shallow shelf zones. 164 geologia croatica 58/2 fig. 1 regional location (inset) and geological map of the study area, showing the main lithostratigraphic units (modified from ivanović et al., 1973). . .' , " , , ' "\ "" deep marine pari of promlna formal/on {.....-8:abjc' zui'anic.. , .,'" flysch formal/oil cretllceous lind pllilleogene cllrbonlltes " , 0, , " d=-­_:z:_ otav;jc member :;:::::;:~~:::: study iir'" :'!"';b::c sto,", 'k~x.~j\=j~ d&b&/o brdo member iidql jellif breccias alluvial pari of prom in i formlltjon 165mrinjek et al.: the benkovac stone member of the promina formation... ably the so-called flysch formation and covers unconformably the cretaceous and palaeogene carbonates in the central part of the region. the flysch formation is of late lutetian age and about 900 m thick, and constitutes the lower part of the palaeogene clastic succession (schubert, 1905; muldini mamužić, 1972; ivanović et al., 1976). the palaeogene clastic succession, together with the carbonate jelar breccia formation (fig. 1), were deposited in a common basinal setting and recorded regional phases of eocene and younger tectonic deformation. the jelar breccia occurs in the basin’s marginal zone, where it overlies deformed mesozoic deposits and is considered to have been the source of carbonate detritus for the promina formation and the underlying flysch formation (ivanović et al., 1976; mrinjek, 1993a, b; sakač et al., 1993). on the basis of seismic lines, deep wells and surface mapping, tari-kovačić & mrinjek (1994) interpreted the palaeogene clastic succession of northern dalmatia as “tectogenic” deposits, formed concurrently with regional tectonic deformation. in their complicated, polyphase tectonic interpretation of the northern dalmatia basin, the authors consider the jelar breccia as “proximal” deposits linked to an early (lutetian– bartonian) compressional deformation of the carbonate platform, and the flysch formation to be their “distal” equivalent. the next phase of tectonic compression (bartonian to possibly oligocene) is thought to have caused folding and thrusting of the underlying platform carbonates, together with the tectonic transport and cannibalization of the flysch and breccia units, which led to the development of a new elongate foreland basin, trending nw–se and filled by the shallowingupward promina formation. in their seismic interpretation, tari-kovačić & mrinjek (1994) consider the final tectonic structure of northern dalmatia to be a result of the duplexing of internal thrusts and basinedge thrusting, which caused uplift and considerable erosion of the promina formation. several papers addressed the sedimentology of the promina formation. in the alluvial upper part of this formation (fig. 1), babić & zupanič (1988) and mrinjek (1993a, b) recognized a predominance of sheet-like and channel-fill, commonly cross-stratified conglomerates. the great lateral extent and internal characteristics of these deposits indicate a braidplain environment with a consistent palaeoflow direction towards the southwest (mrinjek, 1993a). mrinjek (1993b, 1994) described the braided-river facies and architectural elements, and suggested a model of subsidence-driven (i.e., accommodation-controlled) sedimentation on the basis of the spatial distribution of allocyclic facies associations, with the deposition of gravel reflecting syntectonic and post-tectonic phases. mrinjek (1993a, b) pointed out that the subaerial alluvial succession is intimately associated with shallow-marine and shoreline deposits, and represents an extensive, progradational braid-delta system (i.e., a delta formed by braidplain advance). in the vicinity of karin (fig. 1), babić & zupanič (1990) described cyclically-organized deposits representing a progradational, shallowing-upward transition from alternating shelf mudstones and sandstones to shoreface sandstones, and from gilbert-type delta conglomerates to braided-river conglomeratic alluvium. the cyclic stacking of parasequences was attributed to the phases of shoreline progradation alternating with marine transgressions (relative sea-level rises). zupanič & babić (1981) and babić & zupanič (1983) interpreted the lower part of the promina formation, underlying the shallow-marine debelo brdo and benkovac stone members, as deep-marine deposits, comprising calciclastic turbidites intercalated with several thick beds containing huge olistolithic blocks of shallow-marine limestones. the debelo brdo member consists chiefly of calcareous mudstones, whereas the otavac member (fig. 1; unit named after the area of its best exposure at otavac hill) is a succession of alternating calcareous sandstones and conglomerates. all these members are readily distinguishable by their characteristic lithological suites and are also mappable outside of the present study area (fig. 1). 3. study area the study area is in a narrow, se-trending belt (fig. 1) that extends between the debelo brdo hill, about 10 km northwest of benkovac and the mejanica hill, about 1 km southeast of the village of lisičić. the area has a low topographic relief covered with short vegetation (fig. 2), and the general rock bedding here is gently inclined towards the northeast. the benkovac stone member, with its tabular bedding and platy splitting pattern, has long been an imporfig. 2 a broad view from mejanica hill, looking towards the northwest. the occurrence of the benkovac stone member is marked by numerous small quarries and other local excavation pits. 166 geologia croatica 58/2 tant local source of building stone (hence the member’s name), and the numerous small quarries allow detailed study of this calciclastic succession. the sandstone beds are up to 35 cm thick, but mainly thinner, and the sandstone-rich heterolithic succession is readily distinguishable from the underlying and overlying members (see previous section). the succession has been logged at four representative localities (fig. 3). log b is from an excavation pit in the vicinity of benkovac (fig. 4a); log k is from a kimont company quarry (fig. 4b); log l is from an excavation pit near the village of lisičić (fig. 4c); and log s is from a quarry near a former military shootingrange in the vicinity of strelište (fig. 4d). 4. method and terminology the sedimentological data for this study have been acquired by detailed lithostratigraphic logging of the outcrop sections, aided by thin-section analyses. the descriptive sedimentological terminology used is after harms et al. (1975, 1982) and collinson & thompson (1982). by convention, the term “lamination” is used with reference to small-scale (ripple) cross-stratification, and to planar or undulatory parallel stratification in deposits that are finer-grained than sand. the conventional term “(sedimentary) facies” refers to the basic varieties of sedimentary deposits, distinguished descriptively on the basis of their bulk macroscopic characteristics (mineral composition, texture, colour, primary and secondary sedimentary structures, biogenic features, bedding geometry). facies are thus considered to be the basic “building blocks” of a sedimentary succession (harms et al., 1975; walker, 1984). the terms carbonate sandstone, siltstone and mudstone are used for deposits containing a considerable amount of calcareous grains and composed of predominantly sand, silt and mud fractions, respectively, regardless of the actual proportion of calciclastic and siliciclastic components. 5. description of the benkovac stone member the benkovac stone member is about 40 m thick and consists of carbonate sandstones interbedded with finerfig. 3 simplified logs of the benkovac stone member and their location map (inset). the logs have been correlated on the basis of marker storm beds. the figure includes portions of the overlying and underlying lithostratigraphic units (inset). 167mrinjek et al.: the benkovac stone member of the promina formation... grained calcareous deposits. its late eocene age was established on the basis of large benthic foraminifera (nummulitids, discocyclinids) and small pelagic globigerinids. the sandstones are very fineto fine-grained calcarenites, sporadically medium-grained, and consist mainly of various sparitic and micritic grains. quartz grains are subordinate (less than 10 vol. %). the sand grains are subrounded to rounded and generally well to very well sorted, forming a grain-supported framework with mostly point or planar grain contacts. interstitial spaces are filled with a microcrystalline carbonate cement and/or fine-grained calcareous sediment. the finer-grained interbeds are carbonate siltstones and mudstones, moderately to strongly burrowed. recognizable trace fossils represent a mixture of zoophycos and cruziana ichnofacies. the siltstones are calcisiltites composed mainly of medium to coarse silt-sized carbonate grains and up to 10 vol. % of quartz grains. the calcareous mudstones are slightly clayey micrites with scattered silt-sized carbonate and quartz grains. 5.1. carbonate sandstone facies the carbonate sandstone beds are predominantly tabular and separated by mudstone layers, with relatively few beds amalgamated, stacked directly upon one another. the light-brown to grey sandstones are readily distinguishable from the pale yellowish–grey mudstones, even though their weathering patterns are not necessarily dissimilar. the sandstone beds vary considerably in thickness (figs. 5–8) and have been classified into six facies and three subfacies, which are described in the present section. 5.1.1. facies s1: tripartite sandstone beds with planar parallel stratification, hummocky cross-lamination and flat parallel lamination these are the thickest sandstone beds, with average thicknesses in the range of 5 to 25 cm (see logs in figs. 5–8 and outcrop details in figs. 9–15). their basal surfaces are sharp and erosional, with an irregular relief of 1 to 7 cm, whereas their tops are slightly uneven or undulatory, with a relief of 2 to 6 cm. the beds are normally graded, with the particle size ranging from medium to fine or very fine sand. even the thicker beds most often consist of fine to very fine sand and commonly coarse silt at the top. the basal surfaces locally show load casts, which are bulbous or irregularly-shaped features lacking preferred orientation. basal mudstone injections in the form of load-flame structures occur in places (fig. 10). gutter casts (leckie & krystinick,1989; einsele & seilacher, 1982) are sporadically found at the bases of the thickest beds. these isolated grooves are 1–2 cm deep and 4–5 cm wide, filled with sand and occasionally bearing mudstone intraclasts (fig. 13). the groove orientation shows a ne–sw to n–s trend. internally, these sandstone beds characteristically consist of three divisions. the lower division (p) is 3 to 20 cm thick and shows planar parallel stratification (figs. 9–13), although it is locally poorly recognizable in some beds. the strata are 0.2–0.4 cm thick, almost perfectly flat in the lower part and slightly undulatory fig. 4 photographs of the quarries from which the logs in fig. 3 have been derived: (a) log b site near benkovac; (b) log k site in kimont quarry; (c) log l site near lisičić; (d) log s site near strelište. a c b d 168 geologia croatica 58/2 in the upper part. grain size varies from fine or medium to very fine sand. in the thickest beds of this facies, the parallel-stratified division is often underlain by a medium-grained sand horizon, 1 to 3 cm thick, which is rich in mudstone intraclasts. the mudclasts are angular, 0.5 to 6 cm long and flat-lying, parallel to the basal surface and sandstone strata (see figs. 5a, 6, 8, and 13). the overlying, middle division (h) is 4 to 15 cm thick and shows mediumto small-scale hummocky cross-stratification (harms et al., 1975); the latter is here referred to as hummocky cross-lamination. grain size varies between fine and very fine sand on a bed to bed basis, but the division itself shows little internal grading. the strata are gently undulating, typically <10°, varying between convex(hummocky) and concave-upward (swaley) in shape. the lateral spacing (wavelength) of the hummocks is mainly from 15 to 20 cm, and their relief (amplitude) is 1 to 2 cm. the strata are only 0.1 to 0.3 cm in thickness, which also varies laterally with their inclination (fig. 10). these small-scale structures are similar to the “micro-hummocky” cross-lamination of kreisa (1981), attributed to 3d vortex ripples (harms et al., 1982, their figs. 2– 14 and 3–16). some beds show larger-scale hummocky structures at the transition of division p to h (figs. 9, 10, 12 and 13), which have a wavelength in excess of 50–60 cm and can be regarded as “true” hummocky cross-stratification, representing combined-flow conditions (harms et al., 1975; dott & bourgeois, 1982; myrow & southard, 1996). in most cases, at least two or three superimposed sets of hummocky strata are recognizable in division h. the strata within the sets (first-order bounding surface sensu dott & bourgeois, 1982) are concordant with the set’s lower bounding surface (second-order bounding surface), which itself is slightly erosional (fig. 10). the transition from division p to h is either gradual or sharp and slightly erosional (figs. 9–13). the upper division (f) is 1 to 3 cm thick, consists of very fine sand or coarse silt and shows planar parallel lamination. in contrast to the lower division, the strata here are only 0.1–0.2 cm in thickness and commonly show an upward change from slightly undulatory to flat, which renders their lower boundary transitional. in some cases, thin isolated intrasets of asymmetrical wave-ripple cross-lamination occur in this division (see figs. 9–13). 5.1.2. facies s2: bipartite sandstone beds with hummocky cross-lamination and flat parallel lamination the beds of this sandstone facies are similar to those of the previous one, but are generally thinner (average thicknesses of 4–10 cm) and show only two component fig. 5 detailed portions of log b (see indicated in fig. 3), with a general legend pertaining to figs. 5–8. 169mrinjek et al.: the benkovac stone member of the promina formation... divisions. the basal surfaces are sharp and erosional, with a relief of 2 to 3 cm and local load casts (see figs. 14, 16 and 19), and the bed tops are slightly uneven or gently undulatory. the beds show normal grading, with the grain size ranging from fine or very fine sand to very fine sand or coarse silt, respectively. the lower bed division (h) consists of hummocky cross-lamination, similar to the previous facies, but this division here is thinner (2–5 cm), composed of slightly thinner strata, and the wavelength of hummocks is also somewhat smaller (10–15 cm). the overlying upper division (f) is a thin (1–2 cm) set of slightly undulatory to planar parallel laminae composed of very fine sand to coarse silt. division f is often indistinct, either poorly developed or virtually absent (see figs. 14, 16 and 19). 5.1.3. facies s3: sandstone beds with convolute stratification these are sandstone beds that show internal hydroplastic deformation in the form of convolute stratification, although could originally be similar to any of the previous sandstone facies. average bed thicknesses are mainly in the range of 5 to 25 cm, and the deformation is often stronger in the bed’s upper part or is locally limited to only this part. the convolutions typically occur as steep antiforms composed of deformed and locally disrupted or homogenized strata (figs. 17–19). the antiforms are commonly asymmetrical, but generally lack preferential orientation or a recognizable spatial pattern. 5.1.4. facies s4: amalgamated sandstone beds this facies is relatively rare and consists of amalgamated sandstone beds, which themselves represent one or more of the previous facies. the component beds are stacked erosionally upon one another with no intervening mudstone layers. these composite, amalgamated beds are recognizable by their greater thicknesses (up to 35 cm), multiple normal grading and a more complex vertical sequence of structural divisions (see figs. 8 and 19). 5.1.5. facies s5: cross-laminated sandstone beds these are thin sandstone beds (2–5 cm), composed of very fine sand or coarse to medium silt and generally lacking any obvious grain-size grading. their bases are slightly erosional and uneven or undulatory, whereas the tops are slightly undulatory (“wavy”) and occasionally transitional to the overlying silty mudstone (see figs. 13, 15, 16, 20 and 22). many of these sandstone beds, much like the overlying and underlying mudstone layers, are strongly burrowed (fig. 20). internally, the sandstone beds show a wide range of wave-ripple crosslamination types, which form the basis for the distinction of three subfacies (see below). the wave-ripple cross-lamination is recognizable by the presence of uneven or undulatory basal surfaces and lower laminae sets, draped or offshooting geometry of foreset laminae, and chevron-like or form-discordant internal laminae sets (see de raaf et al., 1977; collinson & thompson, 1982). subfacies s5a: sandstone beds with translatory ripples – these beds have undulatory boundaries with well-preserved asymmetrical ripple forms, 1–3.5 cm in amplitude and 6–20 cm in wavelength (figs. 20 and 22). some cross-sets are underlain by a set of 2 or 3 planar laminae covering the erosional basal surface. fig. 6 detailed portion of log k (see indicated in fig. 3); for legend, see fig. 5. 170 geologia croatica 58/2 the well-developed foreset laminae, with discordant silty laminae on the stoss side and a “sweeping” drape of undulatory laminae (figs. 16, bottom) are typical of migrating, translatory wave ripples (allen, 1982). the dip directions of foreset laminae (ripple migration azimuths) are towards the west or northwest. subfacies s5b: sandstone beds with climbing ripples – these beds are slightly thicker, have undulatory and slightly erosional bases, and consist of two or three superimposed sets of asymmetrical, climbing-ripple cross-lamination with preserved stoss-side laminae. the angle of climb varies from 8 to 12° (figs. 15 and 21). ripple dimensions are similar to those of the previous subfacies, and the dip directions of foreset laminae are also similarly towards the west or northwest. as in the previous subfacies, a basal set of 2–3 flat or slightly undulatory laminae can often be seen covering the underlying erosional surface. a similar set of “sweeping” undulatory laminae occur often at the bed top. subfacies s5c: sandstone beds with pinch-and-swell lamination – these sandy to silty beds (see figs. 10, 13, 16, 18a and 21) are the thinnest (0.5–3 cm), characterized by gently undulatory erosional bases and an undulatory, pinch-and-swell internal lamination (similar to the “rolling-grain” ripples of harms et al., 1982 – fig. 3–16), occasionally associated with thin, solitary lenticular cross-sets (small, sediment-starved translatory ripples – allen, 1982). fig. 7 detailed portions of log l (see indicated in fig. 3); for legend, see fig. 5. 171mrinjek et al.: the benkovac stone member of the promina formation... 5.1.6. facies s6: massive sandstone beds with normal grading these are very common, but very thin (1–5 cm), finegrained sandstone beds that lack recognizable internal lamination (see logs in figs. 5b, 6 and 8, and outcrop details in fig. 22). their basal surfaces are sharp and slightly erosional, with a local-scale relief of 0.5 to 1 cm, whereas the tops are flat or only slightly undulatory. the beds are normally graded, ranging in grain size from very fine sand to coarse silt. the thicker beds locally show traces of primary lamination, which suggests a secondary process of sediment homogenization. the “structureless” (massive) appearance of these deposits is thus probably a result of their bioturbation and/or subsequent pervasive weathering at outcrop. 5.2. calcareous mudstone facies the mudstone interbeds (facies m) are common and laterally continuous on an outcrop scale, ranging in thickness between a few mm and 30 cm (see logs in figs. 5–8, and outcrop details in figs. 9, 12–17, 18b and 20–25). most beds contain thin (0.2–1 cm) silty interlayers in the form of flat streaks and distinct lenses with signs of pinch-and-swell lamination, apparently representing sediment-starved small ripples of wave or tidal origin (see reineck & singh, 1975; and the “rolling-grain” ripples of harms et al., 1982). the interlayers usually show normal grading from coarse to fine silt, and many have slightly erosional bases. the vertical spacing of these interlayers varies from a few centimetres to 20 cm or more, and they are commonly disrupted and deformed by animal burrows (see figs. 20 and 22–24). fig. 8 detailed portion of log s (see indicated in fig. 3); for legend, see fig. 5. a b fig. 9 close-up view of a carbonate sandstone bed of facies s1 (a); a corresponding sketch (b) from the site of log b (see fig. 5a). note that the sandstone bed has a sharp, erosional base and consists of a planar parallel-stratified division p (6 cm thick) overlain by a hummocky cross-stratified division h (15 cm) and capped with an undulatory to flat laminated division f (3–4 cm). the underlying and overlying deposits are silt-streaked calcareous mudstones of facies m. 172 geologia croatica 58/2 5.3. other significant features 5.3.1 mud volcanoes small mud volcanoes (reineck & singh, 1975), circular or elliptical in shape, occur locally on isolated bedding surfaces in the mudstone facies m (fig. 25). these conical features are typically 15–32 cm in diameter and 3–6 cm in relief, and apparently represent seafloor mud extrusions buried by younger mud. a few such features have been found at the site of log k, and as many as 12 volcanoes have been counted on a mudstone surface with an area of ca. 50 m2 at the site of log s (see fig. 8, bottom). 5.3.2. trace fossils the sedimentary succession shows a wide range of trace fossils, which abound in the mudstone facies, (figs. 5–8, 20 and 22–24), but are also common in the sandstone beds (fig. 26). the thicker sandstone beds most often lack burrows, except for the top parts. the degree of bioturbation of the thinner bedded and muddy facies generally varies from moderate to high (grades 3–4 sensu reineck, 1963). the majority of identifiable traces belong to zoophycos and cruziana ichnofacies (fig. 26b, d). the grazing helminthoida traces, produced by deposit-feeding animals, are particularly common (fig. 26a) and often show well-developed patterns. the grazing palaeodictyon traces (fig. 26c) have only been found at two localities. according to conventional interpretations (pemberton et al., 1992; bromley, 1996), the cruziana ichnofacies is typical of a sublittoral, neritic shelf zone, whereas the zoophycos ichnofacies is typical for an upper bathyal zone, such as a continental slope environment. however, zoophycos ichnofacies may occur a b fig. 10 close-up view of a carbonate sandstone bed of facies s1 (a), and a corresponding sketch (b) from the site of log l (see fig. 7b). note that the sandstone bed has a sharp, loaded base and consists of a planar parallel-stratified division p (5 cm thick) overlain by hummocky cross-laminated division h (4–5 cm) and capped with an undulatory to flat laminated division f (2–3 cm). the wavelength of hummock forms is about 20 cm, but is considerably greater at the transition of divisions p to h, where medium-scale hummocky cross-stratification (hcs) is recognizable. the underlying deposits are mudstones of facies m with a thin interbed of facies s5c sandstone. the coin (scale) is 2.2 cm in diameter. fig. 11 close-up view of a carbonate sandstone bed of facies s1 from the site of log b (see fig. 5b). note that the sandstone bed has a sharp, erosional base and consists of a planar parallel-stratified division p (6–8 cm thick) overlain by a hummocky cross-laminated division h (6–7 cm) and capped with an undulatory to flat laminated division f (1 cm). the wavelength of hummock forms is about 15 cm. the coin (scale) is 2.2 cm in diameter. a b fig. 12 close-up view of a carbonate sandstone bed of facies s1 (a) and a corresponding sketch (b) from the site of log s (see fig. 8). note that the sandstone bed has a sharp, erosional base and consists of a planar parallel-stratified division p (7 cm thick) overlain by a hummocky cross-laminated division h (4–5 cm), which passes gradually into an undulatory to flat laminated division f (1–2 cm). note the occurrence of mediumscale hummocky cross-stratification (hcs) at the transition of divisions p to h. the underlying and overlying deposits are siltstreaked mudstones of facies m. 173mrinjek et al.: the benkovac stone member of the promina formation... also in low-energy shallow-marine and lagoonal environments (bromley, 1996). for example, uchman et al. (2004) reported on the occurrence of zoophycos and helminthopsis traces in tempestitic offshore-transition deposits, whereas pemberton et al. (2001) and pervesler & uchman (2004) found zoophycos traces in shoreface deposits. it has been suggested that water energy and nutrient supply, rather than bathymetry, may often be the dominant factor controlling the distribution of ichnotaxa (orr, 2003; pervesler & uchman, 2004). this is apparently the case in the benkovac stone member, where some “deep-water” ichnotaxa occur in an undoubtedly shallow-marine, wave-influenced sedimentary succession. 6. interpretation of the benkovac stone member the internal characteristics of the sandstone facies s1–s6, together with their sheet-like bedding geometry (figs. 27 and 28), indicate sand deposition by waves in combination with unidirectional currents (see de raaf et al., 1977; hamblln & walker, 1979; dott & bourgeois, 1982; leckie & walker, 1982; walker et al., 1983). the intervening, silt-streaked mudstone layers of facies m indicate quiet-water config. 13 (a) a portion of the deposits depicted in log l (see fig. 7b); (b) a corresponding sketch, showing a package of the alternating beds of facies m and sandstone facies s5a (lower part) and s5c (middle part), overlain by a thicker sandstone bed of facies s1. the wavelength of hummock forms in the latter bed’s division h is about 20 cm, but is considerably greater at the transition of divisions p to h, where medium-scale hummocky cross-stratification (hcs) is recognizable; note also the localized basal scour and mudstone intraclasts in the lower division p. the coin (scale) is 2.2 cm in diameter. a b fig. 14 close-up view of a carbonate sandstone bed of facies s2 from the site of log l (see fig. 7a). note that the sandstone bed has a sharp, slightly uneven base and consists of a hummocky cross-laminated division h (5–6 cm) that passes gradually into an undulatory to flat laminated division f (3–4 cm). the underlying and overlying deposits are silt-streaked calcareous mudstones of facies m. the coin (scale) is 2.2 cm in diameter. a b fig. 15 (a) some of the deposits depicted in log l (see fig. 7b); (b) a corresponding sketch, showing a package of alternating beds of silt-streaked mudstone facies m and sandstone facies s1 (lower bed) and s5b (upper bed). in the latter bed, the translatory ripples have an amplitude of 2–3 cm and wavelength of 8–12 cm, with an angle of climb in the range of 8–10°; note the preserved thin intrasets of stoss-side laminae. the coin (scale) is 2.2 cm in diameter. 174 geologia croatica 58/2 ditions dominated by hemipelagic suspension fallout and biogenic activity, with the sand-starved seafloor episodically affected by very weak wave action and/or tidal currents. the intimate association of the discrete, erosional sandstone sheets rhythmically alternating with mudstone layers indicates episodic deposition from storm events in an offshore transition zone (swift et al., 1987; snedden et al., 1988; leckie & krystinik, 1989; walker & pllnt, 1992), which means a shelf bathymetric area extending between the average fair-weather wave base and the average storm wave base (reading & collinson, 1996, their fig. 6.6). the offshore transition zone thus occurs outside the shoreface zone (perennially affected by waves) and is subject to episodic incursions of sand during storm events (“event” sedimentation sensu einsele & seilacher, 1982). the actual width, or seaward distance, of these zones depends on the local seafloor inclination and may vary from a few hundred metres to several kilometres (reading & collinson, 1996). accordingly, the sandstone facies are considered to be tempestites (storm deposits), embedded in a “background” mudstone facies (fair-weather deposits). in the following part of this section, the hydrodynamic regime of the offshore transition zone is briefly reviewed as a conceptual basis for the subsequent detailed interpretation of the individual sandstone facies. fig. 16 a section of the deposits depicted in log l (see fig. 7b), showing the alternating beds of silt-streaked, slightly burrowed mudstone facies m and sandstone facies s1, s2 and s5c. the coin (scale) is 2.2 cm in diameter. fig. 17 (a) convoluted sandstone bed of facies s3; (b) a corresponding sketch from the site of log b (see fig. 5a). the underlying and overlying deposits are silt-streaked mudstones of facies m. the coin (scale) is 2.2 cm in diameter. a b a b fig. 18 (a) sandstone bed of facies s3 (middle), covered by the silt-streaked mudstone facies m and underlain by the alternating thin beds of facies m and s5c. (b) sandstone bed of facies s3, underlain and covered by the silt-streaked mudstone facies m alternating with thin sandstone beds of facies s5c. note that the convoluted beds show some preserved primary stratification and most likely represent hydroplastic deformation of deposits analogous to facies s2. details from log b (see fig. 5b). the coin (scale) is 2.2 cm in diameter. 175mrinjek et al.: the benkovac stone member of the promina formation... 6.1. processes in the offshore transition zone as the storm winds push seawater against the coast as a surface current, the resulting coastal setup generates strong bottom currents of seaward-returning (“ebbing”) water, such as the rip currents, ebb surges and the wide and longer-running geostrophic currents (walker & pllnt, 1992; reading & collinson, 1996). as a result, the nearshore water column divides into three internal layers: a highly turbulent surficial layer, an inviscid inner (core) flow layer and a bottom boundary layer (see myrow & southard, 1996 – fig. 1). this latter layer combines the boundary layers produced by waves and currents, such that its lower part is effectively a “combined-flow” boundary layer, where waves and currents interact nonlinearly to produce bottom shear stresses considerably stronger than a simple sum of the two energy components. importantly, the storm-generated current tends to be non-uniform and unsteady, which means that the relative role of waves and unidirectional flow in the boundary layer may vary in both space and time. four basic forces affect the geostrophic current (see myrow & southard, 1996 – fig. 2): (1) the seaward pressure gradient created by the coastal setup; (2) the coriolis force that rotates the current to the right in the earth’s northern hemisphere; (3) the flow-retarding force of bottom friction, and (4) the downslope component of gravity force due to excess weight of sedimentladen water. depending on the temporal history of these fig. 19 (a) compound, amalgamated sandstone bed of facies s4 and (b) a corresponding sketch; detail from log s (see fig. 8, top). note the sequence of component bed divisions, including planar parallel stratification (p), hummocky cross-stratification (h) and undulatory to flat parallel lamination (f). the lower division h shows broader, medium-scale hummocky cross-stratification (hcs), whereas the upper division h shows hummocky cross-lamination (ripple-scale hummocks). the underlying and overlying deposits are silt-streaked mudstones of facies m. a b fig. 20 silt-streaked mudstone facies m, alternating with thin sandstone beds of facies s5a in the upper part; detail from log k (see fig. 6, bottom). ripple forms have an amplitude of 3–5 cm and wavelength of 15–20 cm. the measuring stick is 24 cm. a b fig. 21 (a) some of the deposits depicted in log l (see fig. 7a); (b) a corresponding sketch, showing the alternating beds of silt-streak, burrowed mudstone facies m and sandstone facies s5b. the small ripple forms in the sandstone beds have an amplitude of 1–1.5 cm, a wavelength of 7–8 cm and a low angle of climb (>10°). the coin (scale) is 2.2 cm in diameter. 176 geologia croatica 58/2 four controlling forces, the hydrodynamic regime of a storm event may theoretically represent any of the following cases (myrow & southard, 1996 – fig. 8 and table 1): (1) a temporal increase and then decrease in the magnitude of all four forces; (2) a greater change in bottom friction than in the other forces; (3) a seaward and then landward rotation of the flow direction relative to shoreline, and (4) weak flow conditions at all times, with a predominant oscillatory waves. another consequence of the combined forces is that weaker currents tend to be nearly shore-parallel, whereas the stronger and denser currents are directed offshore at a higher angle. furthermore, the local hydrodynamic behaviour of the storm-agitated bottom water can vary through a whole spectrum of cases defined by the following three end-members (myrow & southard, 1996 – fig. 7): (1) an “ideal” combined-flow geostrophic current, (2) pure oscillatory wave action, and (3) a density-driven flow somewhat analogous to a turbidity current. the various intermediate, “modified” cases are thought to be commonplace in shelf environments. myrow & southard (1996 – fig. 9) also explained as to how the relative role of waves, geostrophic flow and density-driven flow may change during the predepositional and depositional phase of a storm event, with reference to a nearshore (shoreface) site and seafloor sites above and below the storm wave base (i.e., in the offshore transition and offshore zone, respectively). three hypothetical storm events are considered as an illustration. in an event involving relatively weak waves and a decelerating geostrophic current, the wave action increases in the shoreface zone; the relative role of a density-modified current increases and then decreases in the offshore transition zone; and only the densitydriven current will be recorded in the offshore zone. in an event involving a relatively weak geostrophic current and strong waves with decreasing orbital velocities, the process record in all three zones will be nearly identical, except that the geostrophic flow may gradually prevail in the shoreface zone. in a disequilibrium event with high nearshore suspension concentration, the action of a density-driven current will predominate in all three zones. 6.2. interpretation of sedimentary facies the sandstone beds of facies s1 show planar parallel stratification (division p) overlain by mediumto smallscale hummocky cross-stratification (division h) and capped with undulatory to flat parallel lamination (division f). if the sporadic medium-scale hummocky crossstratification is ignored, the sequence of stratification types can be attributed to the action of oscillatory waves (see the bedform stability diagrams in allen, 1982 – figs. 11–18; harms et al., 1982 – figs. 2–14), with the temporal trajectory of seafloor hydraulic regime a b fig. 22 (a) deposits depicted in log b (see fig. 5b); (b) a corresponding sketch, showing the silt-streaked mudstones of facies m with thicker (<0.5 cm) siltstone interlayers and a sandstone interbed of facies s5a (2 cm thick) in the middle. note that some of the interlayers are strongly disrupted by animal burrows. the coin (scale) is 2.2 cm in diameter. a b fig. 23 (a) a portion of the deposits depicted in log b (see fig. 5b, top); (b) a corresponding sketch, showing the mudstones of facies m with siltstone streaks and thicker (< 2 cm) ripple-form lenses. note that many of the silty interlayers are deformed and disrupted by animal burrows. the coin (scale) is 2.2 cm in diameter. 177mrinjek et al.: the benkovac stone member of the promina formation... beginning in the plane-bed field and re-entering this field again after crossing the field of 3d vortex ripples (see also walker et al., 1983; myrow & southard, 1996). the action of a geostrophic current in such a case would be limited to supplying sand to the offshore transition zone, and to aiding briefly the development of medium-scale hummocks. alternatively, the basal division p could partly or entirely be deposited by a geostrophic current, if the latter was sufficiently powerful, laden with sediment and characterized by high suspension fallout rate, such that tractional planebed transport occurred (see lowe, 1988 – fig. 3). the action of waves would then directly follow that of the density-modified current. this possibility is particularly likely for beds that show medium-scale hummocky cross-stratification in the lower part of their division h, because this stratification type is widely attributed to a combined-flow regime. the sandstone beds of facies s2 show a hummocky cross-laminated division h overlain by an undulatory to flat parallel-laminated division f, which can be attributed to oscillatory waves – with the temporal trajectory of the hydraulic regime commencing in the stability field of 3d vortex ripples and passing into the plane-bed field as the sediment supplied becomes finer-grained (see allen, 1982 – figs. 11–18; harms et al., 1982 – figs. 2–14). in this case, the sand delivered to the offshore transition zone by a waning geostrophic current would be thoroughly worked by waves. it is worth pointing out that the action of waves on the seafloor in the offshore transition zone will cease abruptly as soon as the wave base detaches itself from the seafloor. this means that the storm event of sand deposition can abruptly be terminated at a non-zero level of general wave energy; and that is why most tempostites have not only sharp bases, but also sharp tops, which are often also undulatory, showing well-preserved ripple forms. the sandstone beds of facies s1 and s2 also stand out by their greater thicknesses, implying the strongest storm events that affected the offshore transition zone in the present case. geostrophic currents would play a greater role in the deposition of facies s1, attributed to the strongest storm. in this context, the significance of sandstone facies s4 would be to represent strong storms that closely followed one another, such that little or no fair-weather sedimentation took place between these events. fig. 24 microscopic detail of a silt-streaked calcareous mudstone of facies m. note that the silt interlayers vary from thin (1–2 mm) lenses and pinch-and-swell features (lower part), to thicker (2– 3 mm), sharp-based sheets with normal grading (upper part). fig. 25 small mud volcanoes in calcareous mudstone facies m; bedding surface details from the site of log s (see fig. 8, bottom). (a) this volcano has a slightly elliptical plan-view shape with the longer axis of 32 cm and cone relief of 6 cm. (b) this volcano has a circular plan-view shape with a diameter of 28 cm and cone of 5 cm. the coin (scale) is 2.2 cm in diameter. a b 178 geologia croatica 58/2 the erosional bases and normal grading of these tempestite beds are consistent with the notion of an initial, strong ebb-surge followed by a waning geostrophic current that supplied increasingly fine-grained sediment to the offshore transition zone. the sporadic occurrence of gutter casts at the bases of facies s1 beds may theoretically be due to either oscillatory waves or combinedflow currents (myrow & southard, 1996). however, some authors suggested that a unimodal orientation of gutter casts may indicate unidirectional currents, possibly density-modified (hamblln & walker, 1979; leckie & walker, 1982; walker et al., 1983). the ne–sw to n–s trend of the gutter casts in the present case is roughly perpendicular or oblique with respect to the inferred palaeoshoreline (see palaeogeographic reconstruction in subsequent section), which may support the notion of strong ebb-surges or powerful geostrophic currents. this interpretation is further supported by the occurrence of mudclast-rich horizons, considered to be lag deposits of powerful, erosive currents (sepkoski, 1982; walker et al., 1983). the fact that the mudclast lags are uncommon may reflect either their limited preservation potential or deposition from somewhat exceptional currents. the convoluted sandstone beds of facies s3 were apparently deposited in a similar way to those of facies s1 and s2, but underwent a late syndepositional or early post-depositional hydroplastic deformation. these deformed beds indicate partial sediment liquefaction, but are relatively rare, and hence the cause of the deformation itself can be regarded as a rare factor. the seafloor was clearly affected by sporadic shallow liquefaction, as is also indicated by the horizons of mud volcanoes. the origin of mud volcanoes is attributed to the upwelling of pore-water springs through liquefied quickmud (reineck & singh, 1975), which may occur in response to a rapid sediment deposition, cyclic seafloor loading by storm waves or shaking by seismic “ground-roll” wave (i.e., the combined s and l shock waves propagating at ground level). the same factors, or the shearing by an overpassing current (sanders, 1965), could occasionally liquefy the seafloor when it was covered with sand (facies s1 or s2), rather than mud, and hence result in facies s3 (see middleton & hampton, 1973). a more intense liquefaction and/ or pervasive bioturbation are thought to have similarly produced facies 6, which seems to have resulted from a sporadic internal homogenization of freshly-deposited sand beds of facies s5. the sandstone subfacies s5a and s5b indicate storm events with a prevalent role of geostrophic currents, which were sand-laden and characterized by a moderate fig. 26 trace fossils on sandstone bedding surfaces. (a) grazing traces helminthoida, from log k. (b) horizontal feeding burrow system of zoophycos, from log k. (c) grazing trace palaeodictyon, from log s. (d) poorly organized burrowing system of cruziana, from log k. the coin (scale) is 2.2 cm in diameter. a b c d 179mrinjek et al.: the benkovac stone member of the promina formation... (subfacies s5a) to high suspension fallout rate (facies s5b) (see harms et al., 1982). these beds are thin and fine grained, which implies relatively weak, highly subcritical (harms et al., 1975) and low-density currents (sensu lowe, 1982). the orientation of ripple crosslamination indicates currents flowing towards the west (obliquely offshore) or northwest (alongshore). at the other end of the whole spectrum of tempestites are the very thin and fine-grained beds of facies s5c, whose geometry and internal features indicate sand-starved vortex ripple and rolling-grain ripples, implying weak action of “pure” oscillatory waves (allen, 1982; harms et al., 1982). the silt-streaked calcareous mudstones of facies m represent quiet-water sedimentation during the interstorm periods of fair-weather conditions, accompanied by widespread biogenic activity (seafloor burrowing). the fallout of hemipelagic muddy suspension was frequently interrupted by sparse incursions of silt, which can be attributed to weak tidal currents and/or minor seasonal storms. 7. spatial distribution of facies the sedimentary succession is characterized by tabular bedding, with the sheet-like sandstone and mudstone beds showing lateral continuity on an outcrop scale of up to several hundred metres (figs. 27 and 28). two of the thickest sandstone beds of facies s1 can be correlated as markers, on an outcrop to outcrop basis, over a distance of at least 15 km parallel to the inferred palaeoshoreline (fig. 3). the succession of alternating sandstone and mudstone beds shows considerable variation in their thicknesses, but little obvious vertical organization (cf. fig. 3). the only recognizable trend is that the thicker beds of facies s1 are more common, and the mudstone beds of facies m are thinner and less bioturbated, in the middle part of the succession (figs. 5, 6 and 8). this stratigraphic pattern may reflect a temporal change in relative sea level, sediment supply or sea-wave climate. an episode of an accelerated shoreline advance seems likely to have been the case, because it would inevitably increase the frequency and magnitude of storm events affecting the offshore transition zone, and thus increase the supply of sand to the latter. the subsequent, temporal recession of the shoreline could be due to any of the three factors mentioned above, but was most likely caused by a relative sea-level rise (as discussed further in section 9). 8. the origin of contiguous lithostratigraphic members the underlying debelo brdo member and the overlying otavac member of the promina formation are not the main topic of the present paper and hence are characterized here in only broad terms. these contiguous lithostratigraphic units (fig. 1) occur in areas covered with dense vegetation, where their exposure is generally poor. field observations suggest conformable, transitional boundaries of these units with the benkovac stone member (fig. 3). the debelo brdo member – this unit is about 50 m thick and consists of calcarous mudstones with rare, thin a b fig. 27 (a) some of the deposits depicted in log k (see fig. 6) with (b) a corresponding sketch, showing the alternating, sheet-like beds of sandstone and mudstone facies. note the two marker beds of facies s1 that are used for log correlation (fig. 3). fig. 28 (a) photomosaic of the deposits depicted in log s (see fig. 8) with (b) a corresponding sketch, showing the alternating, sheet-like beds of sandstone and mudstone facies. note the same two marker beds of facies s1 that are shown in figs. 3 and 27. a b 180 geologia croatica 58/2 interlayers of very fine-grained sandstone and/or siltstone. the silt-streaked mudstones are similar to those of facies m, and also the thin sandy to silty interlayers resemble those of facies s5c. this facies assemblage indicates deposition below the average storm wave base (offshore zone sensu reading & collinson, 1996 – fig. 6.6). notably, the general lack of deposits analogous to facies s5a and s5b indicates that few, if any, density-modified (turbidity-driven) geostrophic currents have reached this distal shelf zone in the present case. the otavac member – this unit is more than 100 m thick and composed of carbonate conglomerates, sandstones and subordinate mudstones. the conglomerates are clast-supported and typically have a bimodal grainsize distribution, with a pebble framework and sandto granule-size matrix. gravel clasts are subrounded to rounded, derived from cretaceous limestones and subordinately also from rocks of palaeogene, jurassic and triassic age (rare fragments of sandstone, marl, chert, dolomite and rudist molluscs). the conglomerates form sheet-like beds 0.3–2.5 m thick, with uneven erosional bases, crude planar or gently inclined stratification and commonly also a tractional, “rolling” clast fabric of a(t)b(i) type (notation after harms et al., 1975, p. 134). their lateral extent is estimated to be at least several hundred metres. the conglomerate sheets are most often isolated, both underlain and overlain by sandstones or occasionally mudstone facies. the calcareous sandstones are mainly coarsegrained, but include also fineand medium-grained varieties, and are similar in their mineral composition to the sandstone facies of the benkovac stone member. granules are commonly scattered in coarse-grained sandstones. sandstone beds are 0.5–1.5 m thick and show planar parallel, low-angle inclined and locally hummocky or swaley cross-stratification. some beds are nearly massive (“structureless”) and amalgamated into units 3–4 m thick. the calcareous mudstones are silt-streaked and similar to those in the benkovac stone and debelo brdo members. they form isolated layers 10–40 cm thick, with moderate to abundant bioturbation. the three component facies of the otavac member tend to form recognizable coarsening-upward cyclothems comprising either mudstone–sandstone–conglomerate or more rarely mudstone–conglomerate. at least 10 such cyclothems, each several metres thick, have been recognized as stacked upon one another in the stratigraphic succession. the facies assemblage of the otavac member indicates an alternation of lowerto upper-shoreface environment, which was dominated by waves and supplied with gravel from a coeval beach or coarse-grained delta front (see reading & collinson, 1996). the cyclothemic organization of the shoreface succession can be attributed to a series of minor relative sealevel rises followed by normal (progradational) regressions (see also babić & zupanič, 1990). the sporadic mudstone–conglomerate cyclothems may indicate minor forced regressions, but more likely represent episodes of a rapid shoreline advance due to extreme river floods combined with powerful storms. 9. depositional model the promina formation has previously been recognized to be the record of an overall upward transition from deep-water turbiditic facies to braid-delta and fluvial braidplain deposits (babić & zupanič, 1990; mrinjek, 1993a, b, 1994). the present study indicates that the benkovac stone member consists of the offshore transition deposits of a storm-dominated, microtidal shelf variously affected by oscillatory waves and sediment-laden geostrophic currents. the underlying debelo brdo member is considered to represent a corresponding muddy offshore zone, whereas the overlying otavac member represents a wave-dominated shoreface supplied with sediment – an advancing, wide braid-delta front. a somewhat similar braidplain delta, many tens of kilometres wide and passing into a storm-dominated offshore-transition zone, was described from the lower cretaceous of svalbard (nøttvedt & kreisa, 1987; nemec et al., 1988; nemec, 1992). the palaeogeographic scenario for the stratigraphic succession of these three members (fig. 29a) takes into account the se-trending basin margin (cf. fig. 1) and implies a stratigraphic model of a long-term normal regression (fig. 29b) punctuated by minor, shorter-term relative sea-level rises. overall, a considerable rise of relative sea level must have occurred, because the thickness of the otavac member (shoreface deposits) exceeds 100 m, whereas the depth of the mean fairweather wave base is unlikely to have exceeded 15 m (walker & pllnt, 1992). the smaller thickness of the benkovac stone member (ca. 40 m) reflects a relatively low net rate of sediment accumulation in the offshore transition zone (area of episodic sand incursions), markedly different than that in the associated shoreface zone (nearshore sediment trap) and the strongly aggrading braidplain (see the thick alluvium in fig. 1). in sequence stratigraphic terms (emery & myers, 1996), the basinward advance of the thick alluvial upper part of the promina formation (fig. 1) would most likely represent the culmination of a highstand systems tract. the large-scale regressive parasequence is thought to be composite, comprising sets of higherorder, forward-stepping (progradational) and back-stepping (retrogradational) parasequences, probably reflecting the basin’s tectonic subsidence. this suggestion concurs with the earlier interpretation by babić & zupanič (1990). three such crude sets are recognizable in the benkovac stone member, represented by its coarseningto fining-upward trend with further upward coarsening at the transition to the otavac member, 181mrinjek et al.: the benkovac stone member of the promina formation... although the higher-order parasequences themselves are difficult to recognize in this succession. the opposite situation occurs in the otavac member, where the higher-order parasequences are readily recognizable as coarsening-upward cyclothems, whereas their sets are more difficult to pinpoint. this striking difference probably reflects the underlying difference in the physical factors that controlled the supply of sand to the shoreface and offshore transition zone, respectively. the short-term advances and retreats of the braid-delta shoreline were likely due to changes in fluvial sediment supply, the impact of which would be recorded chiefly in the shoreface zone and could be of local extent, rather than basin-wide. the transfer of sand to the offshore transition zone, in turn, would obviously depend on the frequency and magnitude of storm events, rather than fluvial floods and fair-weather wave action. furthermore, the deposition of sand in the two zones would necessarily occur on an out-of-phase basis: the episodes of offshore sand transfer would correspond to shoreface erosion, whereas the longer phases of sediment dispersal and accumulation in the shoreface zone would be coeval with the phases of slow mud deposition in the offshore transition zone. these marked differences might explain why the stratigraphic records of the two zones have different thicknesses and are seemingly incompatible, difficult to correlate on a high-resolution basis. fig. 29 a depositional model for the benkovac stone member, in the form of a schematic palaeogeographic map (a) and a shore-transverse stratigraphic cross-section (b). the vertical scale and seafloor gradient in diagram b are grossly exaggerated for graphical purposes. fwwb = fair-weather wave base; swb = storm wave base; other symbols explained in the legend. for discussion, see text. 182 geologia croatica 58/2 10. conclusions the benkovac stone member of the promina formation consists of alternating, sheet-like calcareous sandstone and mudstone beds deposited in a shallow-marine sublittoral environment. the sedimentary facies succession represents muddy “background” sedimentation punctuated by discrete storm events, which implies an offshore transition zone. the observed spectrum of tempestite sandstone beds indicates a wide range of storm events, varying greatly in their magnitude and the mode of sand dispersal – from the pure action of oscillatory waves to pure geostrophic currents. the majority of tempestites are attributed to a combination of these two end-member factors, with the geostrophic currents often enhanced by a high load of sediment suspension (density-modified currents). the benkovac stone member is underlain by muddy offshore deposits (debelo brdo member) and covered by sandy to gravelly shoreface deposits (otavac member), which pass upwards into braidplain deltaic and alluvial deposits. this whole succession overlies deep-marine turbiditic deposits and is interpreted to be a regressive parasequence deposited as a highstand systems tract during a slow, stepwise rise of relative sea level. the overall shallowing of the basin was apparently controlled by sediment supply, rather than accommodation. the large-scale parasequence consists of progradational and retrogradational sets of higher-order (much smaller) parasequences, but this high-resolution record differs markedly in the shoreface and offshore transition successions. this contrast is attributed to the underlying difference in the physical factors that controlled the supply of sand to these zones. the higher-order parasequences probably reflect incremental tectonic subsidence of the foreland basin floor under the load of active thrust-sheets, and hence reflect the controlling role of basin accommodation. acknowledgements the authors gratefully appreciate and acknowledge the review by wojtek nemec whose comments significantly improved our paper. we would also like to thank josip tišljar and francesco massari for their constructive comments. 11. references allen, j.r.l. (1982): sedimentary structures: their character and physical basis.– developments in sedimentology, 30. elsevier, amsterdam, 1255 p. babić, lj. & zupanič, j. (1983): paleogene clastic formations in northern dalmatia.– in: babić, lj. & jelaska, v. (eds.): contributions to sedimentology of some carbonate and clastic units of the coastal dinarides. excursion guidebook, international association of sedimentologists 4th regional meeting, split, 37–61. babić, lj. & zupanič, j. (1988): coarse-grained alluvium in the paleogene of northern dalmatia (croatia, yugoslavia).– rad jazu, 441 (23), 139–164, zagreb. babić, lj. & zupanič, j. (1990): progradacijski sljedovi u paleogenskom klastičnom bazenu vanjskih dinarida, od sjeverne dalmacije do zapadne hercegovine [progradational sequences in the paleogene clastic basin of the outer dinarids, from northern dalmatia to western hercegovina – in croatian] – rad jazu, 449(24), 319–343, zagreb. bromley, r.g. (1996): trace fossils: biology, taphonomy and applications.– 2nd edn., chapman & hall, london 361 p. collinson, j.d. & thompson, d.b. (1982): sedimentary structures.– allen and unwin, london, 207 p. de raaf, j.f.m., boersma, j.r. & van gelder, a. (1977): wave-generated structures and sequences from a shallow marine succession: lower carboniferous, county cork, ireland.– sedimentology, 24, 451–483. dott, r.h., jr. & bourgeois, j. (1982): hummocky stratification: significance of its variable bedding sequences.– bull. geol. soc. am., 93, 663–680. einsele, g. & seilacher, a. (eds.) (1982): cyclic and event stratification.– springer-verlag, berlin, 536 p. emery, d. & myers, k.j. (1996): sequence stratigraphy.– blackwell science, oxford, 291 p. hamblln, a.p. & walker, r.g. (1979): storm-dominated shallow marine deposits: the fernie–kootonay (jurassic) transition, southern rocky mountains.– can. jour. earth sci., 5, 1673–1690. harms, j.c., southard, j.b., spearing, d.r. & walker, r.g. (1975): depositional environments as interpreted from primary sedimentary structures and stratification sequences.– sepm short course, 2, lecture notes. society of economic paleontologists and mineralogists, dallas, 161 p. harms, j.c., southard, j.b. & walker, r.g. (1982): structures and sequences in clastic rocks.– sepm short course, 9, lecture notes. society of economic paleontologists and mineralogists, calgary, 249 p. ivanović, a., sakač, k., marković, s., sokač, b., šušnjar, m., nikler, l. & šušnjara, a. (1973): osnovna geološka karta sfrj 1:100.000. list obrovac l33–140 (basic geological map of sfry, obrovac sheet).– inst. geol. istraž. zagreb (1962–1967), savezni geol. zavod, beograd. ivanović, a., sakač, k., sokač, b., vrsalovićcarević, i. & zupanič, j. (1976): osnovna geološka karta sfrj 1:100.000. tumač za list obrovac l33–140 (basic geological map of sfry, geology of obrovac sheet).– inst. geol. istraž. zagreb (1967), savezni geol. zavod, beograd, 61 p. kreisa, r.d. (1981): storm-generated sedimentary structures in subtidal marine facies with examples from the middle to upper ordovician of southwestern virginia.– j. sedim. petrol., 51, 823–848. 183mrinjek et al.: the benkovac stone member of the promina formation... leckie, d.a. & krystinick, l.f. (1989): is there evidence for geostrophic currents preserved in the sedimentary record of inner to middle-shelf deposits?– j. sedim. petrol., 59, 862–870. leckie, d.a. & walker, r.g. (1982): stormand tidedominated shorelines in cretaceous moosebar–lower gates interval: outcrop equivalents of deep basin gas trap, western canada.– am. assoc. petrol. geol. bulletin, 66, 138–157. lowe, d.r. (1982): sediment gravity flows ii. depositional models with special reference to the deposits of high-density turbidity currents.– j. sedim. petrol., 52, 279–297. lowe, d.r. (1988): suspended-load fallout rate as an independent variable in the analysis of current structures.– sedimentology, 53, 765–776. middleton, g.v. & hampton, m.a. (1973): turbidites and deep water sedimentation. sediment gravity flows: mechanics of flow and deposition.– short course lecture notes, soc. econ. paleont. and mineralog., pacific section, 38 p. mrinjek, e. (1993a): conglomerate fabric and paleocurrent measurment in the braided fluvial system of the promina beds in northern dalmatia (croatia).– geol. croat., 46/1, 125–136. mrinjek, e. (1993b): sedimentology and depositional setting of alluvial promina beds in northern dalmatia, croatia.– geol. croat., 46/2, 243–261. mrinjek, e. (1994): internal architecture of alluvial promina beds in northern dalmatia, croatia.– acta geol., 24/1– 2, 1–36, zagreb. muldini-mamužić, s. (1972): biostratigrafija paleogenskih slojeva u širem području zadra [biostratigraphy of palaeogene beds in the broader zadar area – in croatian].– nafta, 22, 195–207, zagreb. myrow, p.m. & southard, j.b. (1996): tempestite deposition.– jour. sed. res., 66, 875–887. nemec, w. (1992): depositional controls on plant growth and peat accumulation in a braidplain delta environment: helvetiafjellet formation (barremian–aptian), svalbard.– in: mccabe, p.j. & parrish, j.t. (eds.): controls on the distribution and quality of cretaceous coals. geol. soc. am. spec. pap., 267, 209–226. nemec, w., steel, r.j., gjelberg, j., collinson, j.d., prestholm, e. & øxnevad, i.e. (1988): anatomy of collapsed and re-established delta front in lower cretaceous of eastern spitsbergen: gravitational sliding and sedimentation processes.– am. assoc. petrol. geol. bull., 72, 454–476. nøttvedt, a. & kreisa, r.d. (1987): model for the combined-flow origin of hummocky cross-stratification.– geology, 15, 357–361. orr, p.j. (2003): bathymetric indicators.– in: briggs, d.e. & crowther, (eds.): palaeobiology ii. 2nd ed., blackwell science, oxford, 475–478. pemberton, s.g., maceachern, j.a. & frey, r.w. (1992): trace fossil facies models: environmental and allostratigraphic significance.– in: walker, r.g. & james, n.p. (eds.): facies models: response to sea level change. geol. assoc. of canada, st. john’s, 47–72. pemberton, s.g., spila, m., pulham, a.j., saunders, t., maceachern, j.a., robbins, d. & sinclair, i.k. (2001): ichnology and sedimentology of shallow to marginal marine systems: ben nevis and avalon reservoirs, jeanne d’arc basin.– geol. assoc. of canada, short course lecture notes, 15, 1–343. pervesler, p. & uchman, a. (2004): ichnofossils from the type area of the ground formation (miocene, lower badenian) in northern lower austria (molasse basin).– geol. carpath., 55, 103–110. reading, h.g. & collinson, j.d. (1996): clastic coasts.– in: reading, h.g. (ed.): sedimentary environments: processes, facies and stratigraphy. 3rd ed., blackwell science, oxford, 154–231. reineck, h.-e. (1963): sedimentgefüge im bereich der sudlichen nordsee [sedimentary pattern in the area of southern north see – in german].– senckenberg. naturforsch. ges. abh., 505, 1–135. reineck, h.-e. & singh, i.b. (1975): depositional sedimentary environments.– springer-verlag, berlin, 439 p. sakač, k., benić, j., bahun, s. & pencinger, v. (1993): stratigraphic and tectonic position of paleogene jelar beds in the outer dinarides.– natura croatica, 2, 55–72, zagreb. sanders, j.e. (1965): primary sedimentary structures formed by turbidity currents and related resedimentation mechanisms.– in: middleton, g.v. (ed.): primary sedimentary structures and their hydrodynamic interpretation. soc. econ. paleontol. mineral. spec. publ., 12, 192–219. schubert, r.j. (1905): zur stratigraphie des istrisch–norddalmatinischen mitteleocäns [middle eocene stratigraphy of istria and north dalmatia – in german].– jahrbuch geol. reichsanst., 55, 153–188, wien. sepkoski, j.j.jr. (1982): plat-pebble conglomerates, storm deposits, and the cambrian bottom fauna.– in: einsele, g. & seilacher, a. (eds.): cyclic and event stratification. springer-verlag, berlin, 372–385. snedden, j.w., nummedal, d. & amos, a.f. (1988): stormand fair-weather combined flow in the central texas continental shelf.– jour. sed. petrol., 58, 580–595. swift, o.j.p., huoelson, p.m., brenner, r.l. & thompson, p. (1987): shelf construction in foreland basin: storm beds, shelf sandbodies, and shelf–slope depositional sequences in the upper cretaceous mesa verde group, book cliffs, u.s.a.– sedimentology, 34, 423–457. tari-kovačić, v. & mrinjek, e. (1994): the role of palaeogene clastics in the tectonic interpretation of northern dalmatia (southern croatia).– geol. croat., 47/1, 127–138. uchman, a., janbu, n.e. & nemec, w. (2004): trace fossils in the cretaceous–eocene flysch of the sinop–boyabat basin, central pontides, turkey.– ann. soc. geol. polon., 74, 197–235. walker, r.g. (1984): general introduction: facies, facies sequences and facies models.– in: walker, r.g. (ed.): facies models. geoscience canada, geol. assoc. of canada, st. john’s, 1–9. 184 geologia croatica 58/2 walker, r.g, duke, w.l. & leckie, d.a. (1983): hummocky stratification: significance of its variable bedding sequences: discussion.– geol. soc. am. bull., 94, 1245–1251. walker, r.g. & pllnt, a.g. (1992): waveand stormdominated shallow marine systems.– in: walker, r.g. & james, n.p. (eds.): facies models: response to sea level change. geol. assoc. of canada, st. john’s, 219– 238. zupanič, j. & babić, l. (1981): postanak starijeg dijela promina-formacije (paleogen) sjeverozapadno od benkovca [the origin of the lower part of promina formation (palaeogene), northwest of benkovac, dalmatia – in croatian]. vesnik zavoda za geol. istr. (a), 1980–81, beograd, 38–39, 227–230. manuscript received february 15, 2005. revised manuscript accepted november 11, 2005. geol. croat. 49/2 1179 182 1 1 zagreb 1996 professiollal poi)er legal regulations in the republic of' croatia as well as oil and gas exploration and exploitation activities zeljko ma tisa key words: legal regulation, oil, gas, exploration, production, croatia. abstract allhough croatia does not belong to countries lhal have an espe­ cially rich mineral wealth, il has a long tradition of mining industry. even ihe beginnings of inlcrnaj oil cxp loilatioll occurred in the mid­ dle of the nineteenth century, at the lime when the oil era began with the iirsl oil-well in north america in 1859. the mining legislation in these areas is also vcry old, and it has been recognizable by the existence or the mining provisions and laws since ihe 161h cclllury. special mention has to be made oflile austri­ an general mining law of ir54. that was valid for all countries of the austro-hungarian monarchy. in croatia it remained ill effect until 1945. present mining legislation in croatia has been brought into con­ fonnily with the new legal system of the republic of croatia. but also with the current mining legislation of europe, primarily ofcelltral europe. the field of oil and gas exploration and exploitation ill croatia is covered ch ieny by the provisions of the mining law but also by the concessions act, the law on geological explorations and the mar­ itime code . these legal regulations allow the exploration and exploitation of oil and gas to run smoothly from it mining-and-iegal standpoint. 1. introduction the lengthy tradition of the exploitati on of mineral raw materials in croatia is confirmed by numerous archeological finds from the pre-greco-roman times. the current mining legislation in the croat ian state can be traced through: mining regulations of maximillian n (1573); mining law of joseph][ (1788); mining law or napoleon (1810); austrian general mining law (1854). the austrian general mining law from 1854 remained in effect in croatia until 1945 and it covered all mineral raw materials. in the j.920' s the interest in the exploration and exploitation of oil and gas increased in the territory of the then kingdom of serbs, croats and slovenes, so that the "law on exploralion and proministry of economic affairs of the republi c of cro~lti(l, ulica grada vukovara 78, hr-i 0000 zagreb, croatia. proceedings cessing of mineral oils, natural pitch and gas in the kingdom of serbs, croats and slovenes" came inlo force on 31 march 1922. this new law prescribed the procurement and use of concessions for exploration and exp loitation, while for all other activities the mining law continued to be valid. from 1945 until the present exploration and exploitalion of oil and gas have been regulaled by the regu larly revised mining law. with the formation of t.he republic of croatia in 1990, and on the basis of the constitution of 1990, the new mining law was adopted in 1991; its provisions were broughl into harmony with the new legal order in the state but also with thc market economy suitable for europe. except for the mining law, activities with regard to exploration and exploitation of oil and gas arc also part­ ly regulated by the concession act of 1992, by the mar­ itime code of 1994. and by ihe law on geological explorations of 1986. 2. the constitution of the republic of croatia the constitu tion 01" the republic or croatia estab­ lishes protection for the sea, the seashore and islands, waters, air space, mineral wealth and other natural resources wh ich a re of legal interest to the republic. the law regulates the way in which goods of interest. to ihe republic may be used and exploiled by the holders of the rights to them and by their owners, and provides rules governing compensation for thc restrictions they are subject to. the state guarantees the right of ownership. a for­ eign person may acquire the right. of ownership under conditions specified by the law. the sta te ensures alt entrepreneurs an equal legal status on the marke t. monopolies are forbidden. a very important part of the constitution is that the rights acquired through the investment of capital cannot be lessened by thc law or by any other legal ael. 3. the mining la w the mining law (final draft) has been in effeci in the republic of croatia since 1995. the mining law estab li shed that mineral wealth is the properly of the republic of croatia. the mineral wealth is considered to comprise all organic and inor­ ganic mineral raw materials. namely: i. encrgy raw materials (coal, hydrocarbons in solid, liquid or gaseolls states, all kinds of bituminous and oil rocks , other gases located in the eanh, and radioactive mineral raw materials). 2. mineral raw materials from which metals and their compounds can be produced. 3. non-metallic mineral raw materials (graph ite, s ulphur, gypsum, silica sand , etc.). 4. dimension stone. 5. all sorts of salts and salt waters. 6. mineral and geothermal waters from which mineral raw materials can be won or whose accum ulated heal can be used for energy-produc in g purposes, except for mineral and thermal waters that are used 1'01' curative, ba!neologica! and recreational purpose or as drinking water. 7. all types of aggregates and building stone. the provisions of the law refer to the ex ploration and exploitation of mineral raw materials. exploration of mineral raw materials is considered to com pri se operations and testing with the aim to establish the ex is­ tence, position and form of mineral raw material deposits, their quality and quantity, as well as the exploitation conditions. according to the mining law, the rollowing are not considered to be explorations or mincral raw materials: gcological land prospecting, geological, geochemical, geophysical, pedological and geomcchanical tcsting undertaken to discover various mine ral s, or 10 elaborate geological maps, to test the so il, or to perform scient ific research etc. extraction from dcposits and thc refining of mineral raw materials is consi dered to be exploi tation of mineral raw materi­ als. a concession (approval) for exploration or exploita­ tion of mineral raw materials may bc granted to a legal person with their seat in the republic of croatia that is regist ered for carrying out slieh activity, and to a natur­ al person that has a craft trade for carrying out explo­ ration or exploitation of mineral raw matcrials regis­ tered in the republic of croatia. the approval for exploration and exploitation of oi l and gas is granted by thc govcrnmcnt of the republic or croatia, for techni ­ cal building stone, building sand and gravel , and brick carth it is the cou nty office that is competent for mining matters, while for all other m ineral raw materials by the ministry of economic affairs. for the exploitation of mineral raw materials a com­ pensation is paid at the rate of 2.5% of the income earned from retailing the product. the compensation is paid to the municipality or lown in the territory where the explo itation was undertaken. the holder of any concession for the exploitation of mineral raw matcrials is obli ged, ill parallel with the geologia croalica 49(2 exploitat ion, to carry out explorat ion [or the purpose of renewing and maintaining the reserves. to this cnd hc is obliged to allocate at least 3% of the incomc earned from retailing the mineral raw material. this obligation docs not re fe r to holders of a conccssion when they have confirmed reserves of the mineral raw mater ial for exploitation during a period of a t least 2s years. inspecti on jobs [or superv ising the exploration and exploitation of mineral raw materials are carried out by the mining inspection according to the mining law. 4. the concessions act thi s act governs the ri ght to usc natura! resources and other goods, which are of interest to the republic of croatia. a conccssion may be granted to a domestic or foreign lega l or natural persoll for a maximum period of 99 years. the decision on a concession is made by the cham­ ber of representatives or the sabor (parli ament) of the republic of croatia, unless it is otherwise provided by the law. for exa mpl e, it is laid down by the mining law, that a conccssion for the exploration and exploita­ tion of oil and gas is granted by the government of the republic of croatia, 1'01' exploration and exploitation of building stone, gravel , building gravel and brick carth is granted by the county office, while for all other mineral raw materials is granted by the ministry of econom ic affairs. the decision on the concession is made on the basis or public gathering of tcnders or public invitation for tenders or upon application, unless it is providcd other­ wise by a special law, thc mining law, as such, stipu­ latcd that a concession [or the explora tion and exploi ta­ tion of mineral raw materials is granted upon request. the governmcnt of the repub li c of croatia, the competent ministry or the executive body of the county or of the town and the user of the concession conclude a concession contract. 5. the maritime code the "maritime good" is of publi c interest to the republic of croatia and enjoys its particular protection. the " maritime good" covers internal sea waters and ter­ rilorial waters, their sea-bed and subsoil as well as part of th e land that is, by its nalure, intended for public maritime use or is proclaimed as such. it is considered to include, specifically: seashore, ports, breakwaters, building sl ips, sea-walls, sandbars, rocks, ree fs, mouths of rivers flowing into the sea, canals connected with the sea, as wcll as living and non-l iving natural resources in the sea and sea subsoil , fish , orcs. etc. natural and legal pe rsons may be grant ed authorization for the special use and economic lise of the maritimc good in terms of a concession. the economic zone of the rcpubl ic of croatia com­ prises the sca space from the external border of the termati~a: legal rq;lilillioll~ ill the republic of croatia as well as oil and ca.'; exploralion... 181 rilorial sea in the direction or the open sea to its exterthe fundamental exploration works are carried out nal border allowed by the general international law. in its economic zone the republic or croatia asserts its sovereig n rights with regard to exploration and exploitation, the preservation and management of living and non-living natural resources as well as to energy production utilising the sea , sea currents and wind drifts . in its economic zone the republ ic of croatia has the exclusive right to build artifi cal islands, plants and devices in the sea, sea bottom and sea subsoil. the use and exploration for the purpose of cxploila­ tion or natural resources within the econom ic zone is performed according to special rcgulations. as regards orcs, specia l regulations mean the mining law. the conti nental shelf" of thc rcpubli c of croatia compriscs the sea bottom and sea subsoil outside the external border oj" the territorial sea of the republic of croatia in the direction of the open sea up to the conti­ nental shelves oj" the neighbouring states. the republic of croatia asserts its sovereign righ ts over the continental shelr with regard to its exp loration and exploitation of its natural resourccs. nat ural resources are understood to comprise mineral resources and other non-living wcalth of the sea bottom and its subsoil as well as sea creatures on and ncar the sea bot. tom. exploration and ex ploitation of mineral resources arc also subjec t to special regulations, which in this case, too, is ihe mining law. as distinguished from the economic zone and the continental she lr, where the mining legislation is pre­ cisely determined as the competent one for exploration and exploitation of the mineral resourccs, thi s is not the case. if the internal sea waters and territorial waters are a mailer of concern. the maritime code and the min­ ing law arc in conjlic!, so lhal the solution wi ll proba­ bly be looked for in changing the controversia l provi­ sions or the maritime code. r or thi s reason with regard to mineral resources th e mining law is the " icx spe­ cia lis". 6. the la w on geological explorations the law on geological explorations from 1986 remains in effect in the republic of croatia. a new law on geological activities is being prepared. according to the curre nt law, geological explo­ rations are considcred as: the exploration and establish­ ing of the composit ion and structure of the earth's crust (ianci and sca-bcd ~\i1d subsoil), of mineral raw materi ­ als, exploration of shallow mineral and thelmal under­ ground waters as well as geological test ing before the construction of variolls buildings. this exploration is carried out lising geological, geophysical, geochemical, hydrogeological and engineering-geological mcthods, by surrace and underground works as well as by explo­ ration and structura l drilling. fundamental and regional gcological explorat ions are activi tics of special impor­ lancc. in order to obtain the basic geological data concerning lhe composition and st ructure or the eart h' s crust, and to establish possibilities for locating mineral raw mate­ rials, or to determine engineering-geological, hydrogeo­ logical , geophysical and petrological characteristics of rocks. fundamental exp loration is also considered to include elaboration of geological maps on the scales of 1 :25,000; i :50.000; i: 100,000; 1:200,000 anc! smaller sca les. regional geological explo ration works are car­ ried out in order to acquire the data concerning the composition and structure of the earth 's crust of the given region and to locatc deposits of mincral raw materials and aqu iferous complex struct ures. detailed geolog ical exploration works arc carried out in order to obtain the data concern in g the origin, position and [arm of the deposits or mineral raw mah~ri­ als, and to establish their quan tity, quality and possibili­ ties and condit ions of their explo itati on. these explo­ ration works are performed in conformity with the pro­ visions of the mining law. detailed geological explo­ ration works are also carried out in order to explore underground waters, and lo obtain the data for taking measures aimed at environmcnt protcction. 7. the european energy charter the contract with accompanying acts on acceptance of the european energy charter was signed by croatia in lisbon in deecmber 1994. the europcan energy charter refers to accelerating economi c growth by measures for the libera tion of investments and trade in energy sec tor taking into account the need fo r the most cfficient exploration, pro­ duction, transformation, storage, transportation, distrib­ ution and use of energy. the contracting parties, signatory slates to the charter, bind themselves, among other things, to: ac t to promote access to internat ional market s in order to develop open compctitivc market for energy materia ls and products; take the necessary steps to allow the free passage 01" energy materials and products through their territory over the trading grounds; promote the access and transfer of energy technology across the trading and impartial grounds; establish conditions for access to the capital market for companies and citizens of other contracting par­ ties for the purpose of financing trade and invest­ ments of economic activities in the energy sector; al low access to investment in the energy economy over the ir territory along with the adequate protection of sllch investments; a lso al low the entrance and temporary stay of natural persons in the territory of the contracti ng party, who will be, as key personn el, employed with the investor; ,<2 retain the state soycrcigll ity over the energy products. they decide in particular within their te rrito ry on areas that are available for exploration , on the rene­ wal or rese rves, and on levels of exploitation and exhaustion of deposi ts; they determine and apply var­ iolls fees, rentals , and financial payments; they deter­ mine sa fety measures and conditions [or cilvironlllcill protection, and their participation in exploration and exp loitation of energy goods. certain s ignatory stales have the right 10 transitiona l adjustment measures thai may last up to 5 years , and croatia is among them. the existing legislation of the republi c of croatia in ihe energy sector provides no hindrance to the implementation of the charter. geologin cro:lticn 49/2 8. concluding remarks the mining legislation in the republic of croatia is based on the previolls austrian general mining law of 1854. consequently, the tradition of mining legislation in our count ry is very long. during the very short peri­ od of ex istence of the republic of croatia (since 1990) the m in ing legislation has been brought into harmony with the new legal order in the state but also with the mining legis lation that exists in european countries , especial ly those of central europe. the legal regulations in the field of exploration and exploitation of oil and gas arc contained in the mining law, but also in some other laws that arc today in force in croatia. here is reference made primarily to the con­ cessions act and to the maritime code. current legal regulations in the republic of croatia make it possible that, from the legal sta ndpoi nt , the processes of exploration and exploita tion of oil and gas can operate .in an orderly manner. in the course of time they will be improved, as will be required by the mod­ ern mining-and-oil legis lation in europc. 1. introduction the imotsko polje is situated in the dinarides, in the hinterland of the reverse structures among which mt. biokovo is the most prominent (fig. 1). two facts point to the tectonic activity in the entire area: permanent occurrence of earthquakes with a particular concentration of epicentres around imotski, makarska and vrgorac (herak et al., 1996); recent tectonic activity in the imotsko polje area ivan dragi»evi∆ 1, eduard prelogovi∆ 1, vlado kuk 2 and renato buljan 3 geodetic measurements of the marker points near split, dubrovnik, hvar and on the neighbouring islands, performed between 1994-1996 show that horizontal and vertical displacements up to 2 cm per year occurred (»oli∆ et al., 1996; cigrovski-deteli∆, 1998). in order to define tectonic movements, it was necessary initially to consider previously acquired knowledge on the structural relations and basic classifications of the structural fabric (e.g. rai∆ et al., 1976, 1978; marin»i∆ et al., 1978; maga© et al., 1979; bijuduval & montadert, 1977; herak, 1986, 1991; lawrence et al., 1995; grandi∆ et al., 1997), together with the data on the structural relations at depth (e.g. aljinovi∆, 1984; aljinovi∆ et al., 1984, 1987; laba©, 1987; skoko et al., 1987). especially important are the data on the recent stress field and the possible deformation of structures (ritsema, 1974; anderson & jackson, 1987; grünthal & stormeyer, 1992; herak et al., 1995; marku©i∆ et al., 1998; prelogovi∆ et al., 1999; altiner, 1999). the spatial distribution of earthquake epicentres is particularly significant for definition of the most active faults. the most reliable data for description of tectonic movements were collected by structural geological mapping. a total of 98 outcrops were studied in the imotsko polje area, and the measured data enabled more detailed analysis of the characteristic structural fabric. emphasis was placed on the definition and classification of structures and faults according to their importance in structural fabric and tectonic activity. the structural fabric characteristics are described in such a way that the most active fault sections and displacements of tectonic blocks are stressed, and that the local structures and their deformations are shown. 2. faults, structural relations and displacements in the area shown in fig. 1, the principal structural data are given together with the earthquake epicentres. earthquake foci depict the spatial distribution of the seismotectonically most active zones. these zones are related to the most important faults of the structural fabric. g eol. croat. 52/2 191 196 4 figs. zagreb 1999 key words: active fault zones, stress, structures, earthquakes, imotsko polje, croatia. 1 university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, hr-10000 zagreb, croatia. 2 university of zagreb, faculty of science, department of geophysics, horvatovac bb., hr-10000 zagreb, croatia. 3 institute of geology, sachsova 2, hr-10000 zagreb, croatia. abstract displacements of the adriatic microplate, particularly of its southern part, are of crucial importance for the understanding of recent tectonic movements. deformations of the structural fabric and the resulting tectonic activity also encompass the studied area. there are four most active fault zones mosor-biokovo, zagvozd-vrgoracmetkoviê, trilj-tihaljina-»apljina and imotski-meugorje-popovo polje. in the explored area, these zones delimit the imotsko polje. the calculated regional stress is oriented in the range between 10-190° and 350-170°. the relationship between the orientation of structural units and stress enables reverse displacements, most frequently in the direction of the south and south-east. the change in stress orientation in the mt. biokovo hinterland makes the aforementioned fault zones surrounding the imotsko polje favourably oriented in respect to the stress, thus enabling dextral horizontal tectonic transport of the structures in different fault blocks. in the two fault zones trilj-tihaljina-»apljina and imotskimeugorje-popovo polje, there are 98 outcrops suitable for the structural geology measurements. the obtained data on the local stress orientation and spatial displacement of structures are the most important. the character of faults and the most active fault sections are marked, as well as the local structures that are formed due to strong horizontal component of structural displacement in the studied fault zones. recent tectonic activity is confirmed by the occurrence of earthquakes. spatial distribution of the earthquake epicentres depicts zones of seismotectonic activity that are related to the aforementioned most important fault zones. two of the fault zones trilj-tihaljina-»apljina and imotski-meugorje-popovo polje are especially well marked by earthquakes occurring at depths of between 3 and 15 km. 192 geologia croatica 52/2 earthquake foci concentrations that are connected to the mosor biokovo fault (1) and the zagvozd v r g or ac metkoviê fault (2) depict the relatively steeply inclined zones of tectonic activity (65° in average) to a depth of approximately 10 km. the biggest concentration of foci is in the zone that is related to the mosor biokovo fault (1); this zone acquires a mild inclination only at depths greater than 10 km (fig. 1); the earthquake foci in the vicinity of imotski are located at depth in the range of 18 to 20 km. in the area between the trilj tihaljina »apljina fault (3) and the imotski me u g o r je popovo polje fault (4) earthquakes occur at depth between 3 and 15 km, within a subvertical zone (around 80°). the mosor biokovo fault zone (1) is the most important in the structural fabric. it marks the contact between the two regional structural units dinaricum (1) and adriaticum (2). within the dinaricum, the aforementioned faults delimit the following structural units: biokovo (1), biokovska zagora (2) and imotskibekija (3). the most important faults and structural units have the following characteristics: m o s or -biokovo fault (1) different dip angles were measured, in the 28-80° range, but most frequently between 55 and 75°; the parallel faults of this zone are found in the flysch sediments and along mt. biokovo; within the biokovo unit (1) there are a number of parallel faults, mostly reverse ones, that are either satellite or branching faults of the main zone; there are also frequent signs of tectonic transport along the bedding planes, and retrograde rotation on the steeply inclined fault planes; the faults mostly have the diagonal displacement in the direction of the s-se, occasionally s-sw; z a g v o zd v r g o r ac metkoviê fault (2) the zone is 300 1,300 m wide on the surface and is composed of a sequence of parallel faults and branching faults; the measured dips are in the 46-70° range, only occasionally between the 32-40° and slightly more frequently between 78 and 84°; the biokovska zagora unit (2) is characterised by sequences of local reverse structures and faults; rotation of structures is observed as well as displacements in s-sw direction, most frequently in direction of s-se and se, together with occasional dextral horizontal displacements; t r i lj t i h a l j i na »apljina fault (3) mostly normal faults are found in the 2,000 m wide zone, but there are also reverse faults of opposite vergence, measured dip angles are in the range between 56 and 86°; some of the fault sections are characterised by dextral horifig. 1 structural fabric and zones of seismotectonic activity. legend: 1) regional structural units: dinaricum (1), adriaticum (2); 2) structural units: biokovo (1), biokovska zagora (2), imotski-bekija (3), trebistovo-posuπje-mostar (4); 3) the most important fault of the structural fabric, contact between the regional structural units: mosor-biokovo fault (1); 4) faults delimiting structural units: zagvozd-vrgoracmetkoviê fault (2), trilj-tihaljina-»apljina fault (3), imotski-meugorje-popovo polje fault (4); 5) faults within the fault zones and branches of more important faults; 6) fault zones; 7) reverse faults; 8) normal faults; 9) regional stress orientation; 10) direction of tectonic transport close to the surface; 11) fault sections with horizontal displacement of tectonic blocks; 12) projection of the seismotectonically active zones at a depth of 10 km; 13) earthquake epicentres (magnitudes: a<4, b=4-5, c>6) marked for the following fault zones: mosor-biokovo (a), zagvozd-vrgorac-metkoviê (b), trilj-tihaljina-»apljina and imotski-meugorje-popovo polje (c). zontal displacement of tectonic blocks; the change in character of displacement is observable in direction of ljubuπki, where the reverse fault sections appear; i m o t s ki m e  u g o r je -popovo polje fault (4) reverse faults prevail in this zone, apart from the imotski area, where there are normal faults; the zone is 200 1,000 m wide; dip angles are in the 60-80° range; the faults within the imotski-bekija (3) structural unit have the same characteristics as the boundary faults; this means that the unit actually represents a relatively wide fault zone with a spatial arrangement of the most important, boundary faults and their differently inclined branching faults in between. the observed dextral horizontal displacements enable the conclusion to be drawn that the formation of imotsko polje is connected to the spatial extension in conditions of favourable (diagonal) stress orientation in respect to the strike of the initial, primary fault. possible formation of the extensional structures in the imotsko polje is illustrated in fig. 2. the pliocene and mostly quaternary sediments that were deposited indicate the time of formation. fault characteristics, local structures and movements or tectonic transport of blocks are illustrated by showing parts of the fault zones trilj t i h a l j i na »apljina (3) and imotski m e  u g o r je p o p ovo polje (4). the trilj t i h a l j i na »apljina fault zone (3) is shown in fig. 3. an example is given in the area of zmijavci, south of imotski (fig. 3a), where the existence of the faults that branch from the boundary fault is at first observable. in addition, the secondary strikeslip faults (r1 and r2 systems) appear within the zone, with either dextral or sinistral horizontal displacement of tectonic blocks. gradual bending of the entire zone is also observed, which makes the fault zone section around zmijavci favourably oriented in respect to the stress action. this causes the additional extension in this area and formation of the local pull-apart structure. the stress orientation is not the same along the entire studied fault zone. therefore tectonic blocks are rotated in some places and the fault traces are bent along the strike. local pop-up structures were formed (fig. 3b). the margins of these structures are marked by the steeply inclined reverse faults of opposite vergence. in these cases, the displacement of hanging 193dragiëeviê, prelogoviê, kuk & buljan: recent tectonic activity in the imotsko polje area fig. 2 reconstruction of possible formation of extensional structures in the imotsko polje area (a, b, c, d succession phases). legend: 1) primary fault; 2) extensional zones; 3) fault zones in the recent structural fabric: trilj-tihaljina-»apljina (3) and imotski-meugorje-popovo polje (4); 4) normal and reverse faults; 5) direction of horizontal displacement; 6) generalised stress orientation in the studied fault sections. 194 geologia croatica 52/2 walls can be either sinistral or dextral, and with the diagonal tectonic transport that can even be in a direction opposite to the general direction of horizontal displacement. boundary faults, together with other faults of the structural fabric, form the fault zones. within these zones, fault splays frequently appear, consisting of faults that differ in dip angle and sometimes also in the character of displacement. a good example is found in the incised tihaljina valley that was formed due to horizontal displacement in the boundary fault zone. apart from being bent in the direction of the strike, some faults can be curved in the dip direction. this causes change in the character of displacement. for instance, in the area of klobuk, along the boundary fault of the studied zone, reverse faults are found, which have oblique to subhorizontal dextral displacement (fig. 3c). this fault zone section is characterised by steeply inclined faults. a number of parallel faults are observed, with formation of the local pull-apart structures in their additional fault zones near klobuk. the reverse structures se of tihaljina are relatively unfavourably (almost perpendicularly) oriented in respect to the stress action and reverse displacements prevail. parts of the structures have different directions of tectonic transport, and the fault traces are strongly curved in the vicinity of the trilj t i h a l j i na » a p l j i n a fault zone (3). this is interpreted as the rotation of structures that was aided by horizontal displacement along this fault zone. the imotski m e  u g o r je popovo polje fault zone (4) is shown in fig. 4. near the bekijsko polje that lies between imotski and grude two characteristics are discerned. the section towards imotski is favourably oriented in respect to the stress action. therefore, the fault zone is broadened and the local pull-apart structures are formed. a different stress orientation in the vicinity of grude makes the observed fault zone unfavourably (almost perpendicularly) oriented. this means that only the reverse deformations of structural fabric are possible here, which causes the local narrowing of the bekijsko polje area. the same features explain why a local pop-up structure was formed along the faults on the southern margin of the polje. fig. 3 trilj-tihaljina-»apljina fault zone. legend: 1) traces of the most important faults in this zone; 2) secondary and branching faults within the zone and the reverse faults in the structures s of the zone; 3) secondary strike-slip faults; 4) normal and reverse faults; 5) direction of horizontal displacement of tectonic blocks; 6) fault dip angle; 7) direction and angle of the hanging wall displacement; 8) generalised stress orientation in this part of the zone; 9) local stress; 10) local extension; 11) pull-apart structures; 12) pop-up structures. 195dragiëeviê, prelogoviê, kuk & buljan: recent tectonic activity in the imotsko polje area 3. conclusion recent tectonic activity in the surroundings of the imotsko polje is marked by the horizontal component of structure displacement in the trilj tihaljina »apljina (3) and imotski m e  u g o r je popovo polje (4) fault zones. this activity is inevitably dependable on the position of imotsko polje in the regional structural fabric. of crucial importance for the recent tectonic movements are displacements of the adriatic microplate, particularly of its southern part. within the dinarides, there are rock masses of variable density, different size and spatial position that resist the microplate movements. in this way the stress regime is formed that influences deformations of structural fabric and the activity of faults. in this part of the dinarides the calculated regional stress is oriented between 10-190° and 350-170°. the relationships between the strike of structural units and orientation of recent stress indicate two facts: there is active compression in the area which is most expressed in mt. biokovo, and there is a possibility for the reverse displacements in the s and se direction. most of the measurements taken in the fault zones delimiting structural units have shown the oblique displacement of tectonic blocks. this means that parts of the structural fabric are in rotation and that displacements of structures are formed in reaction to the primary movements of the adriatic microplate. the change in orientation of the action of regional stress from the coastline in direction of imotski is an important fact. this change is a consequence of the displacement and rotation of structural units that led to formation of new relationships between the rock masses. in this way, the structures and faults within the imotskibekija structural unit (3) are mostly positioned favourably (oblique) inclined in respect to the stress orientation. this implies the possibility of dextral horizontal displacement of structures. it is especially well marked along the trilj t i h a l j i na »apljina (3) and i m o t s ki m e  u g o r je popovo polje (4) fault zones. the biggest spatial extension is observed in the imotsko polje area, in the vicinity of tihaljina and klobuk and also in the bekijsko polje. alternatively, oblique displacement of tectonic blocks was frequently observed, mostly with an angle of 20-40°, but also 50-75°. this means that there is variable orientation of the local stress. these variations are causing formation of local extensional or compressional structures, bending of fault planes both in the direction of strike and dip as well as the formation of fault splays and reverse faults of opposing vergence in some places. from the position of the trilj t i h a l j i na » a p l j i n a (3) and imotski m e  u g o r je popovo polje (4) fault zones in the regional structural fabric the following conclusions can be drawn: the area bounded by these faults is an active zone with prevailing dextral horizontal tectonic transport; earthquakes in this subvertical zone happen at depths in the range of 3-15 km; the most active component of the regional structural fabric is the frontal part of the dinarides, which is dominated by the seismotectonically active zone of the mosor biokovo fault (1). 4. references altiner, y. (1999): analytical surface deformation theory for detection of the earth’s crust movements.springer verlag, berlin heidelberg, 100 p. aljinovi∆, b. (1984): najdublji seizmiëki horizonti ne jadrana (the deepest seismic horizons in the northern adriatic.unpublished phd thesis, university of zagreb, 264 p. aljinovi∆, b., bla©kovi∆, i., cvijanovi∆, d., prelogovi∆, e., skoko, d. & brdarevi∆, fig. 4 imotski-meugorje-popovo polje fault zone. legend: 1) traces of the most important faults in this zone; 2) faults along the borders of the bekijsko polje; 3) normal and reverse faults; 4) direction of horizontal displacement of tectonic blocks; 5) generalised stress orientation in the parts of this zone; 6) pull-apart structures; 7) pop-up structures. 196 geologia croatica 52/2 n. (1984): correlation of geophysical, geological and seismological data in the coastal part of yugoslavia.bolletino di oceanologia teoretica ed applicata, ii/2, 77-90. aljinovi∆, b., prelogovi∆, e. & skoko, d. (1987): novi podaci o dubinskoj geoloπkoj grai i seizmotektonski aktivnim zonama u jugoslaviji (new data on deep geological structure and seismotectonic active zones in region of yugoslavia).geol. vjesnik, 40, 255-263. anderson, h. & jackson, j. (1987): active tectonics of the adriatic region.geophys. j. r. astr. soc., 91, 937-983. biju-duval, b. & montadert, l. (eds.) (1977): geological evolution from the tethys to the mediterranean from the mesozoic to present.inter. symp. of the structural hist. of the mediterannean basins, split 25-29 oct. 1976, technip, 13-18, paris. cigrovski-deteli∆, b. (1998): primjena gps mjerenja i geotektonskih informacija u obradi geodinamiëke mreæe crodyn (application of gps measurements and geotectonic information in geodynamic network tooling crodyn, 1994-96).unpublished phd thesis, university of zagreb, 145 p. »oli∆, k., ba©i∆, t., seeger, h., goj»eta, b., altiner, y., ra©i∆, lj., medi∆, z., prebi»evi∆, b., medak, d., marjanovi∆, m. & prelogovi∆, e. (1996): hrvatska u euref ‘94 i projekt crodyn (croatia in euref ‘94 and project crodyn).geodetski list, 4, 331-351, zagreb. grandi∆, s., boromisa-bala©, e. & ©u©ter»i∆, m. (1997): exploration concept and characteristic of the dinarides stratigraphic and structural model in the croatian offshore area.nafta, 48/4, 117-128, zagreb. grünthal, g. & stormeyer, d. (1992): the recent crustal stress field in central europe: trajectories and finite element modeling.journ. geophys. res., 97/b8, 11.805-11.820. herak, mi. (1986): a new concept of geotectonics of the dinarides.acta geologica, 16/l, 1-42, zagreb. herak, mi. (1991): dinaridi, mobilistiëki osvrt na genezu i strukturu (dinarides mobilistic view of the genesis and structure).acta geologica, 21/2, 35-117. herak, ma., herak, d. & marku©i∆, s. (1995): fault-plane solution for earthquake (1956-1995) in croatia and neighbouring regions.geofizika, 12, 43-56. herak, ma., herak, d. & marku©i∆, s. (1996): revision of the earthquake catalogue and seismicity of croatia, 1908-1992.terra nova, 8, 86-94. laba©, v. (1987): neke specifiënosti grae podzemlja dijela centralne zone dinaridskog gravimetrijskog minimuma (some structural characteristics of the subsurface in a part of the central zone of the dinaric grawity low).nafta, 38/10, 547-554, zagreb. lawrence, s.r., tari-kova»i∆, v. & gjuki∆, b. (1995): geological evolution model of the dinarides.nafta, 46/2, 193-113, zagreb. maga©, n. & marin»i∆, & ben»ek, –. (1979): osnovna geoloπka karta sfrj 1:100.00. tumaë za list ploëe k33-35 (basic geological map 1:100.000, geology of the ploëe sheet).inst. geol. istraæ. zagreb (1972), sav. geol. zavod, beograd, 52 p. marin»i∆, s., maga©, n. & ben»ek, –. (1978): osnovna geoloπka karta sfrj 1:100.000. list ploëe k33-35 (basic geological map, ploëe sheet).inst. geol. istraæ. zagreb (1967-1971), sav. geol. zavod, beograd. marku©i∆, s., herak, d., ivan»i∆, i., sori∆, i., herak, ma. & prelogovi∆, e. (1998): seismicity of croatia in the period 1993-1996 and the ston-slano earthquake of 1996.geofizika, 15, 83101, zagreb. prelogovi∆, e., kuk, v., buljan, r., tomljenovi∆, b. & skoko, d. (1999): recent tectonic movements and earthquakes in croatia.geodynamics of the alpe-adria area by means of terrestrial and satellite methods, proceedings, 255-262, zagreb-graz. rai∆, v., ahac, a. & pape©, j. (1976): osnovna geoloπka karta sfrj 1:100.000. list imotski k3323 (basic geological map, imotski sheet).inst. geol. istraæ. sarajevo (1962-1967), sav. geol. zavod, beograd. rai∆, v., ahac, a. & pape©, j. (1978): osnovna geoloπka karta sfrj 1:100.000. tumaë za list imotski k33-23 (basic geological map 1:100.000, geology of the imotski sheet).inst. geol. istraæ. sarajevo (1968), sav. geol. zavod, beograd, 51 p. ritsema, a.r. (1974): the earthquake mechanism of the balkan region.undp project r. 3em/70, 172, unesco, skopje. skoko, d., prelogovi∆, e. & aljinovi∆, b. (1987): geological structure of the earth’s crust above the moho discontinuity in yugoslavia.geophys. j.r. astr. soc., 89, 379-382. manuscript received september 23, 1999. revised manuscript accepted november 12, 1999. scientific meeting dedicated to the 80th anniversary of the life of professor milan herak zagreb, march 5th, 1997 ucojog la lroatlca :jvil geol. croat. 50/2 117 zagreb 1997 foreword iva velic and igor vlahovic thi s volume of geologia croatica is dedicated to pro fesso r mi lan herak, who is 80 years of age thi s year. p rofesso r he rak is one of the 111 0s t promine nt c roat ian geo logists of all tim e. i-ie merited a world­ wide reputation by hi s geolog ical, especially hyd rogeo­ logical investi gations of kars t terrain. on march 5, 1997 (his 80th birthday), a scicntific­ pro fessional symposium was held in herak's honour. this volume prescills the proceedings of that meeting geologia croalicll, editorial board , institute of gcology, sachsova 2, p.o. box 26s, hrl 0000 zagreb. croatia. toge ther with the welcome add resses of representatives of the univers ity, scientific and o ther ins titutions where professor he rak worked and/or co llaborated wi th (in croatian). in addition it contains the professor's acknowledgement to the o rganizers (in croatian), and his bibliography. the editorial board o r geologia croatica extends its congratu la tions and good wishes to professor milan herak! i geol. croat. 49/2 331 332 3 figs. i i zagreb 1996 ahsfracr nore graphic geological presentation for the field development projects based on computer programs niko filipovic this paper illustrates the preparation of colour com­ puter based graphic geological enclosures for field development projects (structural maps, lithofacies maps, effective thickness maps, porosity maps, differ­ ent summary and location maps, geologic profiles, columns and synthesized geological enclosures). due to the great quantity of data available during the development of oil and gas fields, it is necessary to have designed data bases for digital recording. on this basis and with the help of computer programs, we obtain the final form of geological graphic presenta­ tions in a relatively short time. later, if required it is possible to perfectly graphically arrange this for a high­ er level presentation using the designing program. fig. i contour map of the top of ihe "privlaka" reservoir. ina-naftaplin, subiceva 29, hr 10000 zagreb, croatia. proceedings the great advantage of computer graphic enclosures is the time saving for the geologist designers during field development, easier data synthetisation, simple exchange of parts of the enclosures for different pur­ poses in future projects and the easier use of enclosures for other users. in this manner we obtain efficiency in the complex procedure of ficld development. the poster presented some graphic geological enclosures for the crnac, deletovci , privlaka, boksic­ klokocevci and bunjani fields. some samples of these arc shown 011 figs. 1-3. legend • oil ~ water ... .0 deviated well ___ oil-water contact -::~ isobath border of sediments "d not drilled depth of burial i". "'"" .... :::.:'". '-00_900 -90000-"10 .' 0oo~2(} mdo-"", ""'oo_,*, ""'do_",,' water (6ase menti oil isediments) ~ .oo,,~ 4)000 _.,0 ~1aoo_o<o ~2000·"", "''''00_,..0 __ 00_"" water (sedimentsi § .,"~ _05odo-96c ?-. .g.woo970 332 cll ____ -'\000 t-978 0 -----------elt0 flt-1 fig. 2 p:lrl of tile con tour map on lo p or tile " delctovci " reservoir. 1m, .,., i "00 .,:1 '"' i :\ . ." <00 '" ."" ·900 · looo -1100 . ,,", 1400.. >-a: « z a: % w z> >-« .. :j .< 0% a •• ui :z'~ z « -~ w ~o z 0 w () 0 ::j "01' .... ' 1<;_0:: ..o<oue_~e[i 9. a: lithology s ® :"':::-:-j clay ::::-:-~ claymarl :-:-:-; marl i:-:m:-=i limy marl t:-:·:· :-:.:.j sand ~~ conglomeaate ~~ breccia r.-:::::gneiss eli-44 eli-23.230. '" h=81 88m -~ c=j gas (seoiments) gas (basement) c=::lj oil (sediments) ~ oil {basemet>ftj r:-~ water (seoiments) (!m water (basemet>ftj elt-39 ~ ___ oil water contact _ •• _ •• • oil·gas contact __ uncoformity c=j impermeable in reservoir l......j lower pontian deposits i---.j upper pontian deposits "] pliocene and quaternary dl:posi i s ,1,1 j':"'i zone of normal faul t5 ace. to seismic5 11111 fig. 3 gcologic,,1 cross section (b b ') o r ille dcjeloyc i field . legend · '" · """ • water devlatedwell oil water contact border of sediments gco[ogi:j cromie:! 49n saturation c=j gas (sediments) ~ gas (basement) c::::::::j oil (sediments) c::::j oil (basement) c::::::::j water (sediments) c:j water ibasement) elt-29,29tt 80m n kovacs kis et al.indd 1. introduction the papuk mt. belongs to the slavonian mountains in croatia. it is situated in the southernmost part of the tisza megaunit (fig. 1). comprehensive reviews of the geological setting of this area are given by jamičić & brkić (1987), jamičić (1989) and korolija & jamičić (1989). vragović (1965) gave a detailed petrographic description of the gneisses, granitoids and the pegmatites of this region. based on geochemical and isotope data pamić & lanphere (1991) and pamić et al. (1996) grouped granitoids occurring in the slavonian mountains to the hercynian s-type and i-type group. kučan & krmpotić (1911) reported the first alkali feldspar megacrysts from the papuk mt. (pakra creek). they studied the megacrysts under a petrographic microscope and described them as “microclinemicroperthites” in a gneiss host. tajder (1957) mentioned “large-sized pink microcline” crystals occurring in pegmatitic pockets (sloboština creek) and veins in granitoids (pakra creek). vragović (1965) differentiated megacrysts based on their colours and occurrence microstructures in two alkali feldspar megacrysts from the papuk mt., croatia viktória kovács kis1, marija horvat2 and istván dódony1 in the host as porphyric (in adamellite and granodiorite), vein filling and diffuse, metasomatic k-feldspar megacrysts. the al–si ordering and microstructures provide evidence for the thermal history of feldspars. the features of alkali feldspars crystallised from a melt have been well studied. there are three important processes that occur in feldspar crystals during cooling (mcconnell, 1969; eggleton & buseck, 1980; mclaren, 1984; salje & kuscholke, 1984; brown & parsons, 1988; smith & brown, 1988; mcconnell et al., 1997): (1) the homogenous composition disproportionates (exsolutes) into kand na-rich lamellae and lenses at high temperature; (2) the c2/m symmetry degrades to c1̄; (3) albite and microcline twinning occur in both naand k-rich lamellae, respectively. the last two processes are simultaneous. the microstructural features, i.e. the size distribution and the orientation of the kand na-rich domains, the density of twinning and transitional state between the c2/m and c1̄ symmetries reflect the crystallization conditions. willaime et al. (1976) produced a complete list of alkali-feldspar microstructures depending on the melt composition and cooling rate. the microstructures of alkali feldspars crystallised at lower temperatures are relatively less known. tem observations of twinning and exsolution texture in a hydrothermal and two pegmatitic microclines (tibbals & olsen, 1977) extended the study of k-feldspar microtextures below the temperature of the monoclinic–triclinic transformation. k-metasomatism and the formation of microcline under 0.4–1.5 kbar and 250–450ºc in hydrothermal quartz-depleted granites of european granite massifs were investigated by cathelineau (1986). white & barnett (1990) studied untwinned low-microcline grains from the hemlo gold deposit, ontario, which formed below the monoclinic– triclinic transformation. authigenic k-feldspar derived from potassium-rich volcanic ash (haynes, 1994), is characterised by compositional purity and a lack of zoning and twinning. the goal of this paper is to characterise the microstructure of alkali feldspar megacrysts and give evidence for their origin. since the submicron scale mineralogy of the abundant alkali feldspar megacrysts from the papuk mt. was unknown this paper provides geologia croatica 57/2 149–158 7 figs. 2 tabs. zagreb 2004 key words: microstructure, modulation, alkali feldspar, low microcline, thermal history, papuk mt., croatia. 1 department of mineralogy, eötvös l. university, pázmány péter sétány 1/c, h-1117 budapest, hungary; e-mail: vis@geology.elte.hu 2 institute of geology, sachsova 2, hr-10000 zagreb, croatia. abstract two types of megacrysts, one from pakra creek and the other from the sloboština creek locality proved to be low microcline in association with low albite and quartz. a sample from pakra creek is a vein filling megacryst characterised by the absence of twinning. the deduced crystallization temperature is below 460°c. the sample from sloboština creek is a pocket forming megacryst which shows tweed-like texture, with deduced crystallization temperature near to but above 460°c. both samples are characterized by a continuously modulated lattice on the submicroscopic scale. 150 geologia croatica 57/2 151kovács kis, horvat & dódony: microstructures in two alkali feldspar megacrysts... the first description and genetic interpretation of their microstructure. 2. samples and experimental methods megacrysts were collected at two localities: pakra creek valley (p) and sloboština creek valley (s) (fig. 1b). pakra creek megacrysts are pink and they were found in a 10 cm wide vein, which crosses the porphyric granitoid body. sloboština creek megacrysts are pale, greyish pink and they are from a 40 cm sized pocket occurring in the migmatite. their size is about 5x3x1.5 cm. the k-feldspar megacrysts contain crystalline inclusions of plagioclase and quartz. the host rock is coarse grained where the alkali feldspars have the largest size. the chemical and structural inhomogeneities of the megacrysts were measured using a polarizing microscope, a scanning microscope for electron probe microanalysis (epma) and a transmission electron microscope (tem). the modal composition was determined using a polarizing microscope equipped with an ocular net. the value of standard deviations of repeated measurements was below 4%. quantitative chemical analyses were carried out on a jeol jcxa–733 wavelength dispersive (wds) electron microprobe equipped with three spectrometers operating at 15 kv and 36 na, using zaf correction. the following standards were applied: albite for si, al and na, wollastonite for ca and orthoclase for k. the x-ray powder diffraction (xrpd) measurements were performed on a siemens d500 powder diffractometer (cu radiation, 40kv, 20 ma, analogous registration at 0.5° 2θ/min goniometer speed). for the d-value measurements the reflections of accompanying quartz (jcpds #33–1161) were used as an inner standard. the samples for tem observations were obtained by grinding the sample under ethanol and mounting a drop from suspension onto a cu-grid covered by amorphous carbon supporting film. the selected area electron diffraction (saed) patterns and the images were fig. 1 (a) tectonic scheme of the basement in the sw part of the pannonian basin (after šikić, 1995). asterisk shows the position of the investigated area. (b) part of the compiled geological map of the slavonian mts. (jamičić, 2001) with sampling localities (p – pakra, s – sloboština creek). legend: 1) main tectonic lines; 2) alluvium of creeks; 3) deluvial–proluvial deposits; 4) loess; 5) pliocene–quaternary: gravel and sands; 6) albite rhyolite, andesite, basalt; 7) pontian: sand, marl and clay; 8) sarmatian–pannonian: marl and limestone; 9) badenian: conglomerate, limestone, marl; 10) carpathian: conglomerate, sand, clay and marl; 11) ottnangian: conglomerate, sand, gravel; 12) jurassic: limestone; 13) middle and upper triassic: dolomite, dolomitic limestone; 14) lower triassic: sandstone, siltstone, shale; 15) permotriassic: quartz sandstone, conglomerate; 16) devonian–carboniferous: graphitic schist, conglomerate, sandstone; 17) granitoids; 18) gneiss; 19) migmatite; 20) chlorite–sericite schist, metagabbro, marble, amphibolite, amphibole schist; phlaseride granitoid, garnet–staurolite gneiss. b a 150 geologia croatica 57/2 151kovács kis, horvat & dódony: microstructures in two alkali feldspar megacrysts... obtained with a jeol jem 100u microscope operating on 100 kv. 3. results under a petrographic microscope, the pakra creek megacryst shows an inhomogeneous texture, where 10–50 µm sized albite patches form layers in microcline. the extinction of albite patches can be regarded as simultaneous, whereas microcline shows inhomogeneous undulatory extinction (fig. 2a). no twins were observed in this sample. besides the randomly distributed feldspar components, isometric quartz grains also occur. the result of the modal analysis is microcline 82%, albite 15% and quartz 3%. the sloboština creek sample is different to that of pakra creek. the size of the albite patches are about 10 µm, with rather isometric or tabular forms. quartz shows no graphic texture, but the host microcline shows a cross-hatched extinction pattern (fig. 2b). the result of the modal analysis is microcline 88%, albite 9% and quartz 3%. elemental analyses were made at several points in the potassium and sodium rich regions. the composition ranges between or91–96ab8–4an0–4 and ab99–97or0–1an0–2 respectively (table 1). figure 3 shows the measured area of the pakra creek megacryst (a) and back-scattered image of potassium distribution (b). besides minor quartz, the samples proved to be microcline on the basis of their xrpd patterns. both samples show splitted {131} potassic feldspar reflections in their patterns, which prove their triclinic symmetry which is characteristic for microcline. using the calculation introduced by goldschmidt & laves (1954) the value of triclinicity (δ=(d(131)-d(13̄1)) *12.5) is 0.93 and 0.81 for the pakra creek and sloboština creek samples, respectively. using a complex evaluation system method published by neves & godinho (1995, 1999), index of order δsm=15.32[2θ(2̄04)2θ(060)]/0.608 is 0.98 and 0.91 for pakra and sloboština creek megacrysts, respectively. the [110] method (kroll & ribbe, 1983) was used for determining the structural state of some k-feldspars from different rock types in the papuk area, as a measure of the al/si fig. 2 micrographs of alkali feldspar megacrysts. cross-polarised light, the width of the photographs are 1.3 mm. (a) na-feldspar patches in microcline host with no cross-hatched extinction pattern of microcline (pakra creek). (b) cross-hatched extinction pattern of microcline (sloboština creek). legend: ab – na feldspar patches; mc – microcline; qtz – quartz. a b fig. 3 measured area of pakra creek megacrysts (a). back-scattered electron image – potassium-map (b) with measuring points numbered from 1 to 8 (see table 1). a b 152 geologia croatica 57/2 153kovács kis, horvat & dódony: microstructures in two alkali feldspar megacrysts... distribution among the non-equivalent tetrahedral sites (lovas et al., 1999). [110] and [11̄0] translation, calculated from unit cell parameters and unit cell volume obtained by rietveld refinement, gave an al content in t1o site 0.9847 and 0.9806, for the pakra and sloboština creek megacrysts, respectively. among the microcline reflections of the pakra creek sample, low albite peaks appear separately at the following d-values: 4.02 å, 3.77 å, 3.66 å, 3.19 å, 2.86 å and 2.62 å (table 2). besides similar low albite reflections, an additional low albite reflection (d=2.93 å) appears in the xrpd pattern of sloboština creek sample. the transmission electron microscopy allows us to study the structural properties of individual potassium and sodium rich regions. figure 4 is a [100] saed pattern of the feldspar crystal from sloboština creek. the angle between b* and c* vectors equals 90º, so the crystal seems to be monoclinic. on the basis of the icsd database (berndt, 1995) the value of b*/c* ratio for potassic feldspars reaches measured areas of the pakra creek sample 1 2 3 4 5 6 7 8 9 10 11 12 13 wt% sio2 64.38 63.61 67.65 67.79 68.29 63.89 64.01 67.81 67.8 67.59 67.99 64.06 64.75 al2o3 18.70 18.66 19.81 19.63 19.39 18.21 18.57 20.13 19.79 19.80 19.89 18.70 18.65 cao 0.05 0 0.45 0.08 0.14 0.76 0.02 0.48 0.25 0.20 0.27 0 0 na2o 0.78 0.50 11.17 11.44 11.27 0.57 0.55 11.22 11.44 11.35 11.26 0.58 0.93 k2o 15.94 16.27 0.13 0.19 0.11 15.75 16.16 0.14 0.17 0.14 0.15 16.04 15.57 σ 99.85 99.04 99.21 99.13 99.20 99.18 99.31 99.78 99.45 99.08 99.56 99.38 99.90 number of ions on the basis of 8 (o) si 2.980 2.975 2.978 2.987 3.002 2.982 2.982 2.970 2.979 2.979 2.981 2.980 2.989 al 1.021 1.029 1.028 1.020 1.005 1.002 1.020 1.039 1.025 1.029 1.028 1.025 1.015 ca 0.002 0.000 0.021 0.004 0.007 0.038 0.001 0.023 0.012 0.009 0.013 0 0 na 0.070 0.045 0.952 0.976 0.959 0.052 0.050 0.952 0.974 0.969 0.956 0.052 0.083 k 0.942 0.971 0.007 0.011 0.006 0.938 0.961 0.008 0.010 0.008 0.008 0.952 0.917 mol % an 0.2 0.0 2.2 0.4 0.7 3.7 0.1 2.3 1.2 1.0 1.3 0 0 ab 6.9 4.5 97.1 98.5 98.7 5.0 4.9 96.9 97.8 98.2 97.8 5.2 8.3 or 92.9 95.5 0.7 1.1 0.6 91.3 95.0 0.8 1.0 0.8 0.9 94.8 91.7 measured areas of the sloboština creek sample 1 2 3 4 5 6 7 8 wt% sio2 64.40 64.13 67.26 67.73 67.63 68.20 64.43 64.10 al2o3 18.74 18.64 19.79 19.81 19.74 19.55 18.61 18.61 cao 0 0.02 0.25 0.36 0.35 0.13 0.01 0 na2o 0.46 0.93 11.40 11.29 11.26 11.44 0.64 0.40 k2o 16.36 15.56 0.09 0.11 0.09 0.07 15.91 16.16 σ 99.96 99.28 98.79 99.30 99.07 99.39 99.60 99.27 number of ions on the basis of 8 (o) si 2.981 2.982 2.975 2.979 2.981 2.994 2.987 2.985 al 1.023 1.022 1.032 1.027 1.026 1.012 1.017 1.022 ca 0 0.001 0.012 0.017 0.017 0.006 0 0 na 0.041 0.084 0.976 0.962 0.961 0.973 0.057 0.036 k 0.966 0.923 0.005 0.006 0.005 0.004 0.941 0.960 mol % an 0.0 0.1 1.2 1.7 1.7 0.6 0.0 0.0 ab 4.1 8.3 98.3 97.7 97.8 99.0 5.7 3.6 or 95.9 91.6 0.5 0.6 0.5 0.4 94.3 96.4 table 1 chemical data of the studied feldspar crystals. the measured areas of the pakra creek sample are numbered in fig. 3b. an, ab and or stands for caal2si2o8, naalsi3o8 and kalsi3o8 content, respectively. 152 geologia croatica 57/2 153kovács kis, horvat & dódony: microstructures in two alkali feldspar megacrysts... value of 2 in the al/si ordering between orthoclase and microcline. the value of d(020)/d(002) in [100] saed pattern (fig. 4) was measured on a digitised image (resolution=510 dpi, k=1024 dot*å) and the result is exactly 2. this fact, together with the missing odd reflections implicated by the c-centred unit cell, makes the main directions indistinguishable. however, accurate indexing is possible due to disordering parallel to the b*. dob (å) dob (å) irelative irelative pakra sloboština pakra sloboština mineral dlit (å) hkl ilit sample sample sample sample 6.7223 6.7478 0.8 0.6 max microcline 6.736 110 5 6.4775 6.4822 5.5 5 max microcline 6.477 020 5 6.4168 2 low albite 6.376 020 9 5.9217 5.9653 0.6 0.5 max microcline 5.923 1̄ 1̄1 4 5.8211 5.8594 0.3 0.3 max microcline 5.8 1̄11 3 4.6059 4.6201 0.5 0.4 max microcline 4.603 021 3 4.2183 4.2322 5.7 3.9 max microcline 4.213 2̄01 51 4.0239 4.0401 2.1 1 low albite 4.027 2̄01 61 3.9776 3.9882 4.1 2.6 max microcline 3.984 111 12 3.9273 3.9428 0.9 0.7 max microcline 3.924 11̄1 6 3.8257 3.8403 4.5 3.1 max microcline 3.831 130 30 3.7760 3.7903 1.5 1.9 low albite 3.777 111 26 3.7063 3.7231 3.6 2.4 max microcline 3.704 1̄30 30 3.6612 3.6701 1.9 1.8 low albite 3.658 1̄30 34 3.6043 3.6043 0.8 0.7 max microcline 3.595 2̄ 2̄1 9 3.4809 3.4796 7.3 5.8 max microcline 3.484 1̄12 29 3.3674 3.3759 10.4 5.2 max microcline 3.368 220 41 3.2962 3.2903 7.1 5.3 max microcline 3.286 2̄02 48 3.2491 3.2445 100 100 max microcline 3.246 002 100 3.1966 3.1988 9.4 15.7 low albite 3.188 040 100 3.0308 3.0278 5 2 max microcline 3.033 131 19 2.9563 2.9631 4.8 2.6 max microcline 2.958 13̄1 26 2.9374 0.5 low albite 2.928 04̄1 19 2.9057 2.9048 4.3 3.8 max microcline 2.906 041 17 2.8648 2.8720 0.3 0.4 low albite 2.862 131 9 2.7866 2.7900 1.4 0.8 max microcline 2.782 1̄ 3̄2 7 2.6225 2.6232 2.1 1.4 low albite 2.637 1̄32 7 2.5679 2.5729 2.5 1.9 max microcline 2.570 112 8 2.5397 2.5286 1.2 1.3 max microcline 2.536 310 5 2.5252 1.7 max microcline 2.525 240 15 2.4314 2.4352 1.3 0.9 max microcline 2.432 1̄ 5̄1 6 2.3939 0.3 max microcline 2.389 1̄51 2 2.3359 2.3382 1.7 1.4 max microcline 2.334 1̄1̄3 7 2.2819 2.2846 0.4 0.4 max microcline 2.296 3̄ 3̄2 2 2.2288 0.4 max microcline 2.226 3̄32 2 2.1600 2.1614 6.8 4.9 max microcline 2.16 241 21 2.1179 0.7 max microcline 2.113 4̄01 3 2.0785 2.0808 0.8 0.6 max microcline 2.078 311 3 1.9926 1.9926 1.9 1.1 max microcline 1.992 222 5 1.9633 1.9669 7.6 0.6 max microcline 1.974 3̄ 3̄3 5 1.9275 1.9286 1.0 0.6 max microcline 1.925 400 8 1.9160 1.9148 0.7 0.4 max microcline 1.911 331 5 1.8923 1.8916 0.3 0.4 max microcline 1.892 2̄61 1 1.8647 1.8611 1.7 1.4 max microcline 1.866 113 4 1.8210 1.8217 1.2 0.6 low albite 1.820 400 9 1.8059 1.8055 5.1 4.1 max microcline 1.806 043 20 table 2 xrpd data sets of the investigated samples, low albite (jcpds number 20–0554) and maximum microcline (jcpds number 22–0687). 154 geologia croatica 57/2 155kovács kis, horvat & dódony: microstructures in two alkali feldspar megacrysts... streaking parallel to b* is also observable on <1̄01̄> zone saed patterns (fig. 5). in contrast to the [100] pattern in fig. 4, here the streaking is not continuous but the individual reflections are separated at higher hkl values. however, reflections split parallel to b* is reminiscent of the (010) albite twinning; the observed geometry, the measured angles and streaking exclude this interpretation. the albite twinning requires mirror symmetry for doubled reflections, but the <202̄> axes incline to the b* with different angles (87.6º and 90.6º, respectively). these angles are close to the same value of the maximum microcline (88.1º, calculated from data of blasi et al., 1984), and the d(020)/d(202̄) ratio also matches closely with this data. [11̄0] projection of a pakra creek crystallite is seen in fig. 6a. the measured angle between the [111̄]* and [112]* and d-values ratio in fig. 6 support microcline and correspond to published data of blasi et al. (1984). for structural refinement blasi et al. (1984) used a specimen of maximum microcline which was found as an overgrowth on an amazonitic microcline perthite from a pegmatitic pocket in the pikes peak batholith, colorado, so the specimen can be considered as a close maximum microcline end-member. the shape of reflections is slightly streaked parallel to the [111̄ ]* direction. this suggests that the crystallite tends to order towards the ideal triclinic structure. no continuous streaking nor reflection splitting is observable. the bright field image (fig. 6b) of the same crystal shows a tweed-like contrast system. the dense modulation is parallel to the (111̄ ) planes, where the modulation forms continuous, sometimes terminal or zigzag shaped ribbons and lenses corresponding to the streaking in the saed pattern (fig. 6a). the less dense modulation is roughly perpendicular to the (111̄ ) planes. these dark areas represent very fine na-rich domains in the host, with bulk composition over 96% kalsi3o8 (table 1). the periodicity of (111̄ ) modulation is around 0.02 µm. 4. discussion most of the real structural observations of alkali feldspars have been performed on samples crystallised from melts and which underwent solid phase transformations (comprehensive reviews in willaime et al., 1976; ribbe, 1983; brown, 1984; smith & brown, 1988; griffen, 1992; deer et al., 2001). the origin and thermal history of these feldspars have been discussed by several authors (willaime et al., 1976; mclaren, 1984; xu et al., 2000). real structures in alkali feldspars formed at lower temperature and from metasomatic, hydrothermal and diagenetic origin have so far been peripheral for tem studies (e.g. tibbals & olsen, 1977). the result of the xrpd analysis – that the main constituent is near maximum microcline – was supported by tem studies. besides ordered low microcline, minor low albite occurs in the megacrysts showing a close orientation relationship to the host. the observed textures of albite in a potassic feldspar host reveal, under the polarizing microscope, the formation of both megacrysts with no perthitic exsolution: the grain boundaries do not show crystallographic interrelations (figs. 2 and 3) and the simultaneous extinction fig. 4 [100] saed pattern of a crystallite from the sloboština creek sample. note that the reflections are equidistant in both directions and a slight continuous scattering appears parallel to b*. fig. 5 <1̄01̄> zone saed pattern of the pakra creek sample contains elongated and double reflections. 154 geologia croatica 57/2 155kovács kis, horvat & dódony: microstructures in two alkali feldspar megacrysts... of the albite patches in the pakra creek sample support epitaxially oriented intergrowths of these two substances. this type of intergrowth is not observable in the sloboština creek sample, which contains randomly distributed albite patches. this strongly suggests simultaneous crystallisation of albite and potassic feldspar by heterogeneous nucleation. the two-feldspar geothermometer of stormer (1975) provides solid evidence for the low temperature formation of the megacrysts. the albite content (in mole %) of coexisting plagioclase and potassic feldspars in the two megacrysts is 99%, 6% and 99%, 5%, respectively. the extrapolated crystallisation temperatures are below 400ºc, which is probably an underestimated value (parsons & brown, 1984). however, these temperatures and compositions definitely exclude homogeneous crystallisation followed by exsolution processes. the phase diagram of alkali feldspars (smith, 1974; modified by brown, 1981 – in griffen, 1992) also allows us to infer the thermal histories of the samples (fig. 7). the sequences of ordering states and coexisting compositions for sodium and potassic feldspars reflect the paths of their formation. the average composition of the samples, deduced from modal and epma data (table 1), are marked by arrows in fig. 7. in the case of the pakra creek sample the sodium content requires perthitic exsolution and microcline twinning except precipitation below approximately 460ºc. if homogeneous nucleation occurred, the minifig. 6 <11̄0> zone (a) saed pattern of pakra creek sample with the (b) bright field image. note the double reflections on the diffraction pattern. corresponding contrasts in two directions are visible on the bright field image. ba fig. 7 estimated average composition of the starting material (arrows) and the chemical composition of the potassic feldspar component of the megacrysts (asterisks) are shown on the phase diagram of alkali feldspars (after smith, 1974; modified by brown, 1981; in griffen, 1992). abbreviations: p – pakra, s – sloboština creek sample; m – monoclinic; t – triclinic symmetry; ss – solid solution. 156 geologia croatica 57/2 157kovács kis, horvat & dódony: microstructures in two alkali feldspar megacrysts... mal temperature of precipitation, the actual composition, and the ordering state would be around 530ºc and orthoclase, respectively. the observed maximum microcline state has a field in the phase diagram below 460ºc. the streaks in saed patterns and the fine scale modulations in tem images reveal the locally inhomogeneous ordering, i.e. inhomogeneous triclinicity. this is the consequence of kinetically controlled, slow ordering at low temperature. based on the lack of perthitic exsolution and microcline twinning, heterogeneous nucleation below 460ºc seems to be evident. however, a slightly different origin can be concluded for the sloboština creek sample based on the composition (fig. 7) and the presence of cross-hatched extinction pattern (fig. 2b). although there are some uncertainties regarding the origin of the cross-hatched extinction pattern (akizuki, 1972; for summary see mclaren, 1984), it is usually considered as the manifestation of the microcline twinning, which is known to be the result of orthoclase–microcline solid-state transformation (laves, 1950; mclaren, 1984). salje et al. (1985) concluded that in triclinic na-feldspar domains only albite and pericline twin walls are created by spontaneous strain. the sloboština creek sample has a near eutectic composition (or90ab10). the lack of perthitic exsolution and the cross-hatched pattern observed under polarizing microscope without twinned saed patterns suggests a precipitation temperature near to 460ºc at eutectic composition. under these conditions, the alkali feldspar precipitated from fluids as orthoclase, and during further cooling the monoclinic orthoclase transformed to the triclinic phase characterised as intermediate microcline. this is in agreement with the two-feldspar thermometer and the resulting crystallisation temperature can be read as the lowest limit for precipitation of 460ºc. the estimated temperatures for the formation of the megacrysts allow impeded transformations to the maximum microcline state. tem studies revealed that both samples are continuously modulated along their (010) (figs. 4 and 5) and (111̄) planes (fig. 6). modulations cause streaked reflections and a fine-scaled wavy contrast in tem images. these modulations are interpreted as traces of al/si ordering, resulting in increasing triclinicity between intermediate and maximum microcline. it is called a tweed-like contrast system contrary to the real tweed texture, which arises from a fine pattern of microdomains with a high degree of intradomain order, but small overall degree of order (bratkovsky et al., 1996). like the spinodal decomposition which resulted in chemical inhomogenities, the triclinicity (and the unit cell parameters) varies in our structurally modulated samples on a submicron scale. 5. conclusion both the vein filling and pocket forming occurrences, forming by segregation of a melt would require eutectic composition and texture for the kalsi3o8–sio2– naalsi3o8 system. the solid phase segregation of the quartz component from the eutectic system produces a vermicular or spherical texture as a function of undercooling (baker & freda, 2001). the lack of graphic, vermicular or spherical textures and nonperthitic appearence of albite in the microcline host, exclude the formation of megacrysts from a melt. the textural relationship of albite and microcline, and the chemical compositions of the coexisting phases, revealed heterogeneous nucleation at low temperatures. the average value of triclinicity is high for both samples, and the inhomogeneous al/si ordering is reflected by fine scale variations of the cell parameters. the monoclinic orthoclase precipitated slightly above (sloboština creek), and below (pakra creek) 460ºc, transforms to microcline not by twinning, but by a spatially continuous structural modulation. acknowledgements the authors acknowledge ekhard salje and vladimir bermanec for their helpful review, comments and suggestions. special thanks go to stjepan šćavničar, professor emeritus, for his useful corrections. we are also indebted to livia rudnyánszky for her technical help and emotional support. 6. references akizuki, m. (1972): electron-microscopic investigation of microcline twinning.– am. min. 57, 797–808. baker, d.r. & freda, c. (2001): eutectic crystallization in the undercooled orthoclase–quartz–h2o system: experiments and simulations.– eur. j. min. 13, 453–466. blasi, a., brajkovic, a., de pol blasi, c., foord, e.e., martin, r.f. & zanazzi, p.f. (1984): structure refinement and genetic aspects of a microcline overgrowth on amazonite from pikes peak batolith, colorado, usa.– bull. miner. 197, 411–422. berndt, m. (1995): icsd database.– gmelin institute, karlsruhe. bratkovsky, a.m., heine, v. & salje, e.k.h. (1996): strain effects, particularly in phase transitions.– phil. trans. r. soc. lond. a., 354, 2875–2896. brown, i.d. (1981): the bond valence method: an empirical approach to chemical structure and bonding.– in: o‘keefe, m. & navrotsky, a. (eds.): structure and bonding in crystals, vol. 2. academic press, new york, 357 p. brown, w.l. (1984): feldspars and feldspathoids.– nato asi series, ser c., 137, 541 p. 156 geologia croatica 57/2 157kovács kis, horvat & dódony: microstructures in two alkali feldspar megacrysts... brown, w.l. & parsons, i. (1988): zoned ternary feldspars in the klokken intrusion: exsolution microtextures and mechanisms.– contrib. min. petr., 98, 444–454. cathelineau, m. (1986): the hydrothermal alkali metasomatism effects on granitic rocks: quartz dissolution and related subsolidus changes.– j. petr., 27, 945–965. deer, w.a., howie, r.a. & zussman, j. (2001): rockforming minerals. framework silicates: feldspars, vol. 4a.– 2nd ed., geol. soc., london, 972 p. eggleton, r.a. & buseck, p.r. (1980): the orthoclase– microcline inversion: a high resolution transmission electron microscope study and strain analysis. contrib. min. petr., 74, 123–133. goldschmidt, j.r. & laves, f. (1954): the microcline– sanidine stability relations.– geochim. cosmochim. acta, 5, 1–19. griffen, d.t. (1992): silicate crystal chemistry.– oxford univ. press, oxford, 442 p. haynes, j.w. (1994): the ordovician deiske and midbrig k-bentonite beds of the cincinnati arch and the southern valley and ridge province.– geol. soc. america, spec. pap., 290, 80 p. jamičić, d. (1989): osnovna geološka karta sfrj, 1: 100.000, list daruvar, l 33–95 (basic geological map of sfrj 1:100000, daruvar sheet).– geol. zavod zagreb (1975–1988), savezni geološki zavod beograd, beograd. jamičić, d. (2001): osnovne geološke značajke slavonskih planina s osvrtom na našičko područje [basic geological characteristics of the slavonian mts. with special regards to the našice area – in croatian].– matica hrvatska, našički zbornik, 6, 29–36. jamičić, d. & brkić, m. (1987): osnovna geološka karta sfrj, 1:100.000, list orahovica, l 33–96 (basic geological map of sfrj, 1:100000, orahovica sheet).– geol. zavod zagreb (1971–1986), savezni geološki zavod beograd, beograd. korolija, b. & jamičić, d. (1989): osnovna geološka karta sfrj, 1:100.000, list našice, l 34–95 (basic geological map of sfrj, 1:100000, našice sheet).– geol. zavod zagreb (1988), savezni geološki zavod beograd, beograd. kroll, h. & ribbe, p.h. (1983): lattice parameters, composition and al, si order in alkali feldspars.– in: ribbe, p.h. (ed.): feldspar mineralogy. 2nd ed., reviews in mineralogy, 2, 57–99. kučan, f. & krmpotić, m. (1911): mikroklinmikropertit iz pakre [microclinemicroperthite from pakra – in croatian].– glasnik hrvatskog prirodoslovnog društva. godište xxiii, zagreb. laves, f. (1950): the lattice and twinning of microcline and other potash feldspar.– jour. geol., 58, 548–571. lovas, gy., horvat, m. & buda, gy. (1999): k-feldspars of the granitoids, pegmatites and migmatites from papuk polymetamorphic complex in east slavonia, croatia.– berichte der deutschen mineralogischen gesellschaft, no.1., beihefte zum european journal of mineralogy, 11, stuttgart, p. 149. mcconnell, j.d.c. (1969): electron optical study of incipient exsolution and inversion phenomena in the system naalsi3o8–kalsi3o8.– phil. mag., 19, 221–229. mcconnell, j.d.c., de vita, a., kenny, s.d. & heine, v. (1997): determination of the origin and magnitude of al/si ordering enthalpy in framework aluminosilicates from ab initio calculations.– phys. chem. minerals, 25, 15–23. mclaren, a.c. (1984): transmission electron microscope investigations of the microstructures of microclines.– in: brown, w.l. (ed.): feldspars and feldspathoids. nato asi series, ser c. 137, 373–409. neves, l.j.p.f. & godinho, m.m. (1995): estimação expedita do ordenamento al–si do feldspato potássico – uma reapreciação [expeditious estimation of al–si ordering in potassic feldspar – re-evaluation – in portuguese].– memórias e notícias, publ. dep. ciências da terra e do mus. lab. mineral. geol. univ. coimbra, 120, 15–24. neves, l.j.p.f. & godinho, m.m. (1999): structural state of k-feldspar in some hercynian granites from iberia: a review of data and controlling factors.– can. min., 37, 691–700. pamić, j. & lanphere, m. (1991): hercynian granites and metamorphic rocks from the mts. papuk, psunj, krndija and the surrounding basement of the pannonian basin in slavonija (northern croatia, yugoslavia).– geologija, 34, 81–253, ljubljana. pamić, j., lanphere, m. & belak, m. (1996): hercynian i-type and s-type granitoids from the slavonian mountains (southern pannonian basin, northern croatia).– n. jb. miner. abh., 171/2, 155–186. parsons, i. & brown, w.l. (1984): feldspars and the thermal history of igneous rocks.– in: brown, w.l. (ed.): feldspars and feldspathoids. nato asi series, ser c. 137, 317–371. ribbe, p.h. (1983): aluminum–silicon order in feldspars; domain textures and diffraction patterns.– in: ribbe, p.h. (ed.): feldspar mineralogy. 2nd ed., rev. in min., 2, 21–55. salje, e. & kuscholke, b. (1984): on the structural phase transitions in alkali feldspars.– bull. min., 107, p. 539. salje, e., kuscholke, b. & wruck, b. (1985): domain wall formation in minerals. 1. theory of twin boundary shapes in na-feldspar.– phys. chem. min., 12, 132–140. smith, j.v. (1974): feldspar minerals. i. crystal structure and physical properties.– springer-verlag, heidelberg, 627 p. smith, j.v. & brown, w.l. (1988): feldspar minerals. crystal structures, physical, chemical and microtextural properties. vol. 1.– 2nd ed. springer, new york. stormer, j.c. jr. (1975): a practical two feldspar geothermometer.– am. min., 60, 667–674. šikić, k. (1995): prikaz geološke građe medvednice [a review of a geological structure of the medvednica mt. – in croatian].– in: šikić, k. (ed.): geološki vodič medvednice, 7–30, institut za geološka istraživanja ina-industrija nafte d.d. – naftaplin, zagreb. 158 geologia croatica 57/2 tajder, m. (1957): petrografsko istraživanje zapadnog dijela papuka [petrographic investigation of the western part of the papuk mt. – in croatian].– ljetopis jazu, 62, 316–323. tibbals, j.e. & olsen, a. (1977): an electron microscope study of some twinning and exsolution textures in microcline amazonites.– phys. chem. minerals, 1, 313–324. white, j.c. & barnett, r.l. (1990): microstructural signatures and glide twins in microcline, hemlo, ontario.– can. min., 28/4, 757–769. willaime, c., brown, w.l. & gandais, g. (1976): physical aspects of exsolution in natural alkali feldspars.– in: wenk, h.r. (ed.): electron microscopy in mineralogy. springer-verlag, berlin, 248–257. vragović, m. (1965): graniti i gnajsi papuka [granites and gneisses of the papuk mountain – in croatian].– unpubl. phd thesis, university of zagreb, 222 p. xu, h., veblen, d.r., buseck, p. & ramakrishna, b.l. (2000): tem and sfm of exsolution and twinning in an alkali feldspar.– am. min., 85, 509–514. manuscript received march 04, 2004. revised manuscript accepted november 08, 2004. trubelja et al.indd triassic magmatism in the area of the central dinarides (bosnia and herzegovina): geochemical resolving of tectonic setting fabijan trubelja1, klaus-peter burgath2 and vesna marchig2 1. introduction in the central dinarides of bosnia and herzegovina, triassic magmatic rocks are associated with platform carbonate sediments and also occur frequently within palaeozoic–triassic allochthonous series (mountains of central bosnia, sana–una palaeozoic complex, southeast bosnia near čajniče, foča, tjentište and kalinovik – fig. 1). towards the southeast, the triassic magmatism continues into the territory of montenegro. the same formations can also be found in slovenia, croatia, and serbia. previous investigations resulted in two different conclusions about the tectonic setting and origin of the triassic magmatic rocks: (1) bebien et al. (1978) classified the rocks as a product of subduction-initiated magmatism, while (2) pamić (1984) explained them as a product of the rifting of continental crust. a new investigation by knežević et al. (1998) yielded ambiguous results: within plate magmatism combined with volcanic arc influence. trubelja et al. (2000) came to a conclusion similar to pamić’s explanation, as they described contamination of the magmatic rocks with a continental crust component which can be best explained by magmatic activity in the course of opening of a continental rift. the aim of this work is to contribute new microscopic and geochemical data to the clarification of the tectonic setting of the triassic magmatism in bosnia and herzegovina. microscopic studies were performed for the classification of the rocks but they served mainly for estimating the intensity of alteration with possible changes of the original chemical composition, and from this the selection of appropriate geochemical discrimination diagrams (with elimination of elements which could be mobile in the course of alteration). ‘classic’ and newly developed geochemical diagrams were used for determination of the geotectonic setting of the magmatic rocks including highly evolved members. rare earth elements patterns were also investigated and included in the discussion. geologia croatica 57/2 159–170 13 figs. 2 tabs. zagreb 2004 key words: triassic, magmatic rocks, geochemistry, rare earth elements, morb, arc magmatism, bosnia and herzegovina. 1 academy of sciences and arts of bosnia and herzegovina, bistrik 7, 71000 sarajevo, bosnia and herzegovina. 2 bundesanstalt für geowissenschaften und rohstoffe, stilleweg 2, 30655 hannover, germany; e-mail: k.burgath@bgr.de. abstract triassic magmatic rocks in the central dinarides in bosnia and herzegovina are known from two separate geotectonic units: (1) the adriatic carbonate platform (outer dinarides) and (2) the palaeozoic–triassic allochthonous complex. they are assigned to the same regional, genetic and geochemical unit. their emplacement age is inferred from contacts with the surrounding marble and sedimentary rocks (postanisian for intrusives and ladinian for effusives). the magmatic rocks display different levels of emplacement and crystallization (intrusive, effusive and dyke rocks). they represent different stages of magmatic differentiation, from gabbro/basalt via diorite/andesite to granodiorite/dacite and granites. the most frequent dyke rock is diabase. pillow basalts indicate eruption under subaquatic conditions. pyroclastic rocks within the volcano-sedimentary unit point to the temporary explosive character of orogenic magmatic activity. most rocks are affected and modified by post-magmatic alteration and hydrothermal fluids. this led to the formation of spilite, keratophyre, quartz keratophyre and rarely k spilite. new geochemical data support the opinion that subduction was the main process which triggered the triassic magmatic activity in the central dinarides. although some of the investigated rocks reveal morb characteristics (in the selected geochemical discriminations), most samples are enriched in all elements which are reported as characteristic for arc magmatism at convergent margins including incorporation of sediments. 160 geologia croatica 57/2 161trubelja, burgath & marchig: triassic magmatism in the area of the central dinarides... 2. overview of geology and petrography triassic magmatic rocks in the dinarides form a spatial, genetic(?) and geochemical unity with a wide range of rocks varying from basalt/gabbro to rhyolite/granite. all levels of solidification are present, i.e. intrusive, effusive and hypabbysal rocks. the most frequent dyke type is of diabase composition. effusive and dyke rocks are partly modified to spilites, keratophyres and quartz keratophyres. k-spilites with adularia as their main constituent are also present, but quite rare (trubelja, 1978). the jablanica gabbro is the most investigated rock with its halo in the surrounding sediments (fig. 2). in the northwestern part this intrusive body is in contact with an anisian limestone which was thermally metamorphosed to marble. the first description of the contact, the developed contact-metamorphic silicates (garnet, albite, chlorite, sericite, titanite, epidote), and the skarn deposit of tovarnica with magnetite ore was published by cissarz (1956). after čelebić (1967), the intrusion age of this gabbroic complex is post-anisian. in the same region a corresponding contact-metamorphic zone was found on the left side of the river crima (fig. 3). another huge basic intrusion occurs in the radovan mt. (novi travnik), rather similar to the jablanica gabbro. rb/sr isotopic data of this rock determined an age of 223–232 million years (pamić & lovrić, 1980). effusive rocks include basalts, andesites and dacites and their modified equivalents spilite, keratophyre and quartz keratophyre. they are mostly in concordant position within volcanic–sedimentary associations of middle triassic ages (palaeontological determinations; fig. 4). the most intense volcanic activity was of ladinian age. pyroclastic rocks (tuffs) are common within the volcanic-sedimentary association, showing that the volcanic activity was partly explosive. also pillow lavas have been observed indicating underwater volcanic activity. in some localities (vareš, hrčavka river on tjentište, valley of the vrbas river) mixing of lava with sedimentary material can be observed. limestone xenoliths within lava flows frequently occur. the effusive rocks in these locations display typical amygdaloidal fabric. the amygdules with diameters reaching more than 10 centimetres are filled predominantly with calcite. 3. methods of investigation with respect to their general classification, qualification of samples for chemical analysis and applicability of discrimination methods, 15 rocks were selected covering the range of triassic magmatism in bosnia and fig. 1 sketch map of selected occurrences of triassic magmatic rocks in bosnia and herzegovina. legend: 1) pyroxene andesite – river doljanka; 2) keratophyre – trešanica, bradina; 3) basalt – vareš; 4–6) gabbro-norite – jablanica; 7) olivinebearing gabbro-norite – novi travnik; 8) andesite or dacite – trnova, sanski most; 9) sodium rhyolite – fojnica; 10) quartz-diorite – ćusine, jajce; 11) basalt – babino selo, vrbas river valley; 12) basalt, vrbas river valley; 13) basalt (spilite) – tjentište; 14) basalt – kalinovik; 15) basalt – dobro polje. 160 geologia croatica 57/2 161trubelja, burgath & marchig: triassic magmatism in the area of the central dinarides... herzegovina. polished thin-sections of these rocks were prepared and studied microscopically. the aliquots of selected samples were crushed in a shatter box with agate inlay for chemical analyses. one gram of powder was mixed and melted with 5 g libo2 at 1200°c for 20 minutes. the obtained glass was analysed by x-ray fluorescence; phillips pw 1400 and pw 1480 wavelength dispersive spectrometers were used. analytical precision was better than 0.5% (relative) for major elements and 1–10 ppm for trace elements. the quality of the results was controlled with certified reference materials (crm) (i.e. bcr, community bureau of reference, brussels). after being used in xrf the glass was crushed and dissolved in an acid mixture (hcl–hno3) in a microwave oven. from this solution trace elements below the detection limit of xrf were determined, including rare earth elements. the instrument used was an inductively coupled plasma-mass spectrometer (icp-ms) perkin elmer sciex elan 5000. analytical precision was controlled using crm, and was better than 5% (relative). 4. petrographic description of samples the selected representatives of triassic magmatism in bosnia and herzegovina were classified as follows according to their mineralogical composition: 1 – porphyric pyroxene andesite, weakly altered, doljanka river valley (sample t99/1); 2 – keratophyre, strongly altered, trešanica, bradina (sample t99/2); 3 – (tholeiitic?) basalt, strongly altered, vareš (sample t99/3); fig. 2 geological map of the jablanica gabbro massif with sedimentary country rocks (from čelebić, 1967). 162 geologia croatica 57/2 163trubelja, burgath & marchig: triassic magmatism in the area of the central dinarides... 4 – cumulate gabbro-norite, strongly altered, jablanica (sample t99/4); 5 – cumulate gabbro-norite with subplanar fabric, weakly altered, jablanica (sample t99/5); 6 – cumulate gabbro-norite with subplanar fabric, weakly altered, jablanica (sample t99/6); 7 – olivine-bearing gabbro-norite, weakly altered, novi travnik (sample t99/7); 8 – andesite or dacite, strongly altered, trnova, sanski most (sample t00/5); 9 – sodium rhyolite, medium alteration, fojnica (sample t00/6); 10 –fine-grained quartz diorite, strongly altered, ćusine, jajce (sample t2/00/1); 11 – tholeiitic basalt, medium alteration, babino selo, vrbas river valley (sample t2/00/3); 12 – tholeiitic basalt, strongly altered, vrbas river valley (sample t2/00/4); 13 – tholeiitic basalt, medium alteration, tjentište (sample t3/00/2); 14 – olivine-bearing tholeiitic basalt, strongly altered, kalinovik (sample t3/00/3); 15 – tholeiitic basalt, strongly altered, dobro polje (sample t3/00/4). the mineral assemblages and petrographic details are listed in table 1. the modification of the mineral content in the weakly altered samples is expressed by devitrification of glass (in t99/1, t2/00/3), by replacement of olivine to various extents by nontronite (t99/7) or carbonate (t3/ 00/4), by replacement of pyroxene by clinoamphibole (t99/7) or by a mixture of chlorite, sphene, carbonate, quartz/chalcedony or very fine-grained undeterminable fig. 3 profile through the contact of gabbro– diorite and platy crinoidal limestone with a magnetite ore body (after čelebić, 1967). legend: 1) platy crinoidal limestones; 2) contact-metamorphic limestones/marbles; 3) scarn; 4) gabbro diorite. fig. 4 basalt concordant in the volcanogenic–sedimentary association, area of konjic, jablanica, prozor (after čelebić, 1967). legend: 1) upper triassic limestones and dolomites; 2) cherts and basalts; 3) reddish shales and radiolarites; 4) haematite; 5) basalt; 6) middle triassic reddish limestones. table 1 mineral assemblages and petrographic details of the rocks. 162 geologia croatica 57/2 163trubelja, burgath & marchig: triassic magmatism in the area of the central dinarides... number type of rock; texture composition estimation of of sample location and deformation alteration t99/1 pyroxene andesite; porphyric phenocrysts: weak; doljanka plagioclase with pyroxene and glass inclusions; cloudy alteration to zoisite, mainly introduction of chlorite, carbonate; co2 and h2o pyroxene (two types): fresh augite and pseudomorphs (with chlorite, carbonate, sphene, chalcedony); ti-bearing magnetite; groundmass: originally glass, with magnetite grains; recrystallized to a mixture of plagioclase, chlorite, leucoxene, carbonate t99/2 keratophyre; microporphyric phenocrysts: strong; trešanica, bradina plagioclase (albite): corroded and deformed, with clouds of sericite and alteration of plagioclase, chlorite; mafic grains; probable amphibole (and pyroxene?), replaced by chlorite and carbonate; introduction of si, k, opâque phases, replaced by leucoxene; mg, fe, co2; quartz (very rare); strongly schistosed, groundmass: with tendency to augen plagioclase laths in fluid arrangement, sericite, leucoxene texture; chlorite–sericite and carbonate–quartz veins t99/3 (tholeiitic?) microporphyric, phenocrysts: strong; basalt; vesicular mafic phases, totally replaced by pumpellyite±epidote; probable introduction vareš groundmass: of ca and loss of si plagioclase laths (cores filled with pumpellyite), diopsidic augite, chlorite; vesicules filled with pumpellyite, prehnite, quartz t99/4 cumulate gabbro subhedral granular, plagioclase with clinopyroxene and magnetite inclusions; round hypersthene slightly (t99/5,6) to t99/5 norite; partly with subplanar (~10 vol. %, partly replaced by diopside); diopside with inclusions of biotite, strongly (t99/4) altered t99/6 jablanica plagioclase fabric amphibole and opâque phases; ilmenite; quartz (rare; in interstices); replacements: plagioclase replaced by sericite, epidote, prehnite, chlorite, pumpellyite; pyroxene replaced by green amphibole (cores), actinolite and barroisite (rims), biotite, sphene, carbonate, chlorite; ilmenite replaced by biotite (biotite replaced by chlorite, sphene) t99/7 olivine-bearing subophitic plagioclase; orthopyroxene; clinopyroxene; olivine (partly as corroded very slight gabbronorite; inclusions in pyroxene), replaced by nontronite; titanomagnetite– (replacement of olivine, novi travnik orthopyroxene symplectites; biotite oikocrysts with inclusions of pyroxene, titano plagioclase, or biotite rims enclosing corroded titanomagnetite; green magnetite) fibrous amphibole and clay minerals in interstices between plagioclase; t00/5 andesite; microporphyric, phenocrysts: strong; trnova, sanski intergranular plagioclase with albite-rich rims, filled with sericite and epidote; replacement of all most pseudomorphs of chlorite ± sphene after mafic phases (biotite; amphibole; primary phases, pyroxene?) formation of epidote opâque grains (few); groundmass: plagioclase (albite-rich), mafic grains, primary quartz, apatite; alteration phases: sericite, sphene, secondary quartz; aggregates and network of epidote (very common), chlorite, carbonate t00/6 sodium rhyolite, pilotaxitic phenocrysts: medium; fojnica albite (few grains; stained by fluid inclusions and opâque dust); modified by introduction groundmass: of ca, co2, k, ba albite laths and interstitial quartz (anhedral); numerous microveins filled with sericite and green clusters of radiating tourmaline (zoned); network of anhedral carbonate and individual carbonate grains t2/00/1 quartz diorite, subhedral granular, plagioclase (completely replaced by sericite aggregates and epidote very strong; fine-grained; graphic patches); interstices: graphic intergrowth of plagioclase and quartz; some abundant sericite and ćusine, jajce skeletal opâque grains with leukoxene rims; some clinoamphibole grains epidote formation (replaced by chlorite) t2/00/3 tholeiitic basalt; microporphyric, phenocrysts: medium; babino selo, hyalopilitic plagioclase (albite-rich; filled with sericite, chlorite, epidote); introduction at least vrbas valley mafic phases (pyroxene, probably some amphibole), completely replaced of k, h2o by chlorite, opâque dust, sphene, very fine-grained phyllosilicates; opâque phases; groundmass: formerly glass, with plagioclase laths; glass replaced by a fine-grained mixture of chlorite, sphene, phyllosilicates, opâque dust t2/00/4 andesite; microporphyric, phenocrysts: very strong; vrbas valley hyalopilitic, plagioclase, largely replaced by carbonate+chlorite; introduction of si, ca, vesicular mafic phases, completely replaced by chlorite±quartz; co2, h2o groundmass: formerly glass, altered to a fine-grained mixture of chlorite, sericite, opâque dust, sphene; vesicles filled with quartz t3/00/2 tholeiitic fine-grained plagioclase (stained by sericite and zoisite?) and diopsidic augite (timedium; basalt (spilite); subophitic bearing) with interstitial chlorite and patchy sphene; numerous patches introduction of co2 and tjentište filled with chlorite and a radiating sheet silicate; cr-bearing spinel h2o (290 ppm cr in analysis!) t3/00/3 olivine-bearing subophitic phenocrysts: strong; tholeiitic basalt; vesicular olivine (euhedral pseudomorphs, filled with phyllosilicates, carbonate) with introduction of co2 and kalinovik primary inclusions of cr-bearing spinel); h2o plagioclase: rounded grains, stained by phyllosilicates and epidote; groundmass: plagioclase (strongly stained) and clinopyroxene with interstitial phyllosilicates, chalcedony, opâques; vesicles filled with very fine-grained phyllosilicates (fe-rich saponite/griffithite?); some radiated carbonate aggregates t3/00/4 tholeiitic basalt subophitic some carbonate pseudomorphs after olivine? (spinel inclusions!); strong; (diabase), similar vesicular rather fresh; plagioclase laths strongly stained by sericite and chlorite; as in t3/00/3 to t 3/00/3; accessory cr-bearing spinel in the groundmass dobro polje 164 geologia croatica 57/2 165trubelja, burgath & marchig: triassic magmatism in the area of the central dinarides... phyllosilicates (t99/1, t2/00/3), and by replacement of plagioclase by sericite, zoisite, chlorite, carbonate, or epidote (t99/1, t3/00/2, t2/00/3). strongly altered samples are characterised by the above, but more advanced modes of replacement. clinoand orthopyroxene are mainly conserved (t99/1, t99/5, t99/6), but may be largely to completely replaced by secondary phases (t99/2, t99/3, t99/4, t99/7, t2/00/3, t2/00/4) in both slightly and strongly altered samples. chromium-bearing spinels are rather common in the basalt samples, but are not altered. they occur either as inclusions in former olivine in the strongly altered sample t3/00/3 or as an accessory phase in olivinefree rocks (t3/00/2, t3/00/4). accessory ti-bearing magnetite is common in andesites (weakly to strongly altered) and is rimmed by sphene, which is also present as patches throughout the rocks. the gabbroic rocks (t 99/4, t 99/6) contain ilmenite with rims of biotite which is replaced by chlorite. it can be concluded from microscopic observations that cr, ti, and v (incorporated in spinel) and, to some extent, the hree (conserved pyroxene!) showed rather immobile behaviour during alteration. the contents of na, k, ni (formerly incorporated in olivine), and to some extent of ca, mg were evidently modified and are unable for consideration in the discrimination of the original tectonic setting of the investigated rocks. 5. chemical composition of basaltic and gabbroic rocks the chemical composition of the 15 analysed samples is shown in table 2. eleven samples have the composition of basalts or gabbroic rocks (sio2<54%) and will be discussed later. for samples t99/4 to t99/6 (gabbroic rocks with cumulate fabric) the further use of basalt discrimination diagrams below is subject to the restricted location 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 sample t99/1 t99/2 t99/3 t99/4 t99/5 t99/6 t99/7 t00/5 t00/6 t2/00/1 t2/00/3 t2/00/4 t3/00/2 t3/00/3 t3/00/4 sio2 52.07 63.33 46.54 53.70 51.92 51.49 49.42 60.64 70.35 56.53 51.00 53.35 51.09 47.63 51.34 tio2 1.00 0.57 0.83 0.94 0.89 0.96 0.57 0.48 0.13 1.02 1.16 0.85 1.13 0.80 1.09 al2o3 16.74 15.35 16.62 17.14 17.92 15.91 16.68 17.77 15.64 17.79 19.48 15.79 16.72 13.91 17.28 fe2o3 8.53 6.19 7.77 8.00 9.03 10.83 9.36 5.00 0.50 7.88 8.79 6.11 7.71 6.23 7.74 mno 0.16 0.09 0.11 0.14 0.19 0.22 0.17 0.12 0.01 0.07 0.15 0.14 0.09 0.12 0.11 mgo 2.78 3.29 7.09 3.64 5.38 6.38 8.47 1.90 0.97 1.77 4.82 2.06 6.83 3.33 6.64 cao 7.66 1.00 12.15 6.52 10.01 10.36 11.23 4.46 1.52 7.09 2.91 8.98 6.61 13.24 5.22 na2o 5.27 6.15 3.24 4.20 2.92 2.65 2.41 4.57 7.41 2.75 5.21 3.26 4.78 5.37 4.97 k2o 0.19 0.72 0.20 1.65 0.99 0.69 0.86 1.79 0.63 1.94 2.36 1.75 0.98 0.48 1.33 p2o5 0.22 0.12 0.14 0.20 0.12 0.07 0.06 0.20 0.06 0.19 0.16 0.15 0.19 0.15 0.17 loi 4.99 2.89 4.94 3.38 0.22 0.19 0.39 2.57 2.51 2.50 3.59 6.97 3.45 8.22 3.65 total 99.62 99.70 99.63 99.51 99.60 99.75 99.63 99.49 99.74 99.52 99.63 99.41 99.58 99.48 99.54 cs 1.21 0.91 0.28 2.17 2.27 1.01 2.61 3.49 0.50 1.83 2.21 2.83 0.33 0.32 2.64 rb 4.58 13.9 2.12 62.8 35.8 22.3 36.0 40.6 5.32 40.6 46.8 32.2 13.2 10.8 27.0 ba 133 196 60 316 216 171 167 131 52 398 208 197 211 59 303 th 7.17 5.75 1.87 6.64 3.43 1.78 3.10 8.38 0.80 6.50 8.30 4.20 2.50 2.70 3.80 u 2.20 1.46 0.52 1.50 0.97 0.49 0.73 1.80 0.24 1.89 0.66 1.20 0.75 0.80 0.86 ta 0.79 0.59 0.63 0.73 0.40 0.28 0.32 0.61 0.094 0.54 0.61 0.36 0.61 0.57 0.78 nb 10.5 7.63 8.40 8.49 5.29 3.62 3.52 7.54 1.13 7.40 8.60 5.40 10.7 9.90 12.6 pb 11.6 2.06 1.52 4.82 7.53 3.85 6.62 9.73 1.09 7.90 5.20 6.90 2.30 2.90 4.80 sr 242 63 63 184 328 236 246 370 114 261 90 119 280 198 338 zr 160 137 66 126 70 52 57 139 41 65 58 46 59 50 60 hf 4.38 3.83 1.92 2.84 1.97 1.26 1.53 3.69 1.24 4.30 4.10 3.20 2.50 2.20 2.80 y 33.0 15.8 18.4 28.2 20.6 19.9 16.0 16.1 2.14 22.2 24.2 17.0 28.6 22.1 26.7 cr 18 141 238 41 71 55 256 21 38 31 12 51 311 280 366 ni udl 18 69 10 10 udl 86 6 9 8 10 14 46 68 38 v 216 119 235 194 259 216 195 122 12 178 143 137 306 235 289 sc 23 16 30 23 33 46 42 9 2 27 25 21 50 43 50 zn 104 66 39 110 96 87 66 106 8 29 99 240 52 76 63 la 22.4 15.2 8.69 18.2 11.6 7.38 9.26 23.2 4.11 20.7 28.7 15.1 13.0 12.6 16.4 ce 47.2 31.8 18.9 40.5 26.0 16.9 19.6 44.7 8.29 34.5 48.9 26.4 29.4 28.5 33.9 pr 5.67 3.56 2.59 5.29 3.44 2.38 2.70 5.50 0.96 5.19 6.14 3.35 3.44 2.93 3.85 nd 23.4 13.2 11.2 22.0 14.6 10.8 11.4 20.5 3.67 22.8 26.1 14.8 14.4 12.9 16.4 sm 5.42 2.67 2.82 5.09 3.59 2.93 2.77 3.86 0.69 4.82 5.24 3.37 4.02 2.94 3.80 eu 1.35 0.65 0.95 1.34 1.16 1.04 0.84 0.97 0.18 1.24 1.59 0.99 1.25 1.01 1.16 gd 5.82 2.68 3.27 5.35 3.87 3.41 3.03 3.43 0.59 5.00 5.61 3.60 4.08 3.31 4.25 tb 0.92 0.44 0.54 0.82 0.60 0.57 0.48 0.49 0.079 0.81 0.93 0.60 0.66 0.59 0.73 dy 5.69 2.73 3.37 5.04 3.73 3.62 2.94 2.81 0.40 5.13 5.63 3.85 4.54 3.41 4.30 ho 1.18 0.58 0.71 1.01 0.77 0.74 0.59 0.55 0.07 1.04 1.18 0.80 0.92 0.72 0.91 er 3.50 1.78 2.03 2.94 2.23 2.22 1.76 1.66 0.18 3.02 3.57 2.43 2.63 2.18 2.65 tm 0.51 0.27 0.30 0.44 0.32 0.33 0.25 0.25 0.026 0.46 0.52 0.35 0.38 0.31 0.37 yb 3.38 1.81 1.95 2.83 2.13 2.14 1.63 1.68 0.170 2.91 3.14 2.27 2.45 2.29 2.43 lu 0.56 0.29 0.31 0.46 0.34 0.35 0.26 0.28 0.027 0.48 0.56 0.39 0.39 0.37 0.39 table 2 bulk rock chemical compositions. oxides from sio2 to p2o5 (in wt. %) by xrf; total iron as fe2o3. trace elements and ree (in ppm) by icp–ms; udl – under the detection limit. 164 geologia croatica 57/2 165trubelja, burgath & marchig: triassic magmatism in the area of the central dinarides... application of these diagrams to rocks of non-cumulate origin. figure 5 shows the ree content normalized on a chondrite basis (wakita et al., 1971) of eleven samples with basaltic or gabbroic composition. there is no major discrepancy between the patterns of basalts and gabbroic rocks. the patterns in general are typical for e-morb with enrichment of lree in comparison to hree (la/ lucn between 3 and 5). two different signatures were used for samples with observed weak alteration and for samples with strong alteration; no significant differences between these two stages of alteration are recognized. it is well known that strong alteration can influence lree and transfer them into a soluble phase. we explain the same contents of lree in strongly altered samples with transfer of lree from the original primary minerals during their disintegration to secondary minerals. a common and approved tool for the specification of tectonic settings of basaltic rocks is the ti/100–zr– 3y diagram introduced by pearce & cann (1973). most of the basalts and two gabbroic rocks plot into field b (fig. 6), which is the ambiguous field between island arc basalts, ocean floor basalts, and calc-alkalic basalts. hence this diagram is not very suitable for discrimination of the tectonic setting of rocks which fall into field b. the field should be further divided, but the fact that none of the samples is situated in the field of “within plate basalts” (d) is considered as a geochemical argument against rifting as the tectonic setting of the investigated rocks. the plotted samples include those fig. 5 rare earth elements normalized on a chondrite basis (wakita et al., 1971) for basaltic and gabbroic samples. two different signatures show two different stages of alteration: full line and full circles for weakly altered samples and stripped line and empty circles for strongly altered samples. fig. 6 ti–zr–y diagram for differentiation between basalts from different tectonic settings (after pearce & cann, 1973). 166 geologia croatica 57/2 167trubelja, burgath & marchig: triassic magmatism in the area of the central dinarides... with weak as well as those with strong alteration, but they do not cluster separately. this indicates that ti, zr, and y behaved in a largely immobile manner during alteration. müller et al. (1992) proposed th/yb vs. ta/yb diagrams for discriminating between subductioninduced basaltic volcanism against basaltic rocks crystallised from mantle-derived melts in other tectonic settings. th is considered to be derived from the sedimentary component of the subducted slab, although the exact mechanism responsible for the enrichment of th with respect to ta in subduction-induced volcanism is controversial. yb is used as a denominator to neutralise the effects of partial melting and/or fractional crystallisation. figure 7 shows the discrimination diagram after müller et al. (1992): most of the investigated rocks are within the field of orogenic magmatism (calc alkaline and shoshonitic rocks). here also no clustering of the investigated samples with strong alteration is visible compared to those with weak alteration. another commonly used diagram for the discrimination of basalts from different tectonic settings is the hf/3–th–ta plot proposed by wood (1980). thorium is used as indicator for the influence of subducted sediments (as in müller et al., 1992) and hf and ta are considered as two immobile elements. this diagram should be especially suitable to identify volcanic arc basalts. the possible mobility of th during alteration could move the position of samples in the direction of morb-types, but if samples plot in the volcanic arc field, then there is no doubt about a volcanic arc setting. this is exactly the case for our samples plotted in fig. 8. fig. 7 th/yb vs. ta/yb diagram for discriminating between tholeiitic, calc-alkaline and shoshonitic basalts (after müller et al., 1992). fig. 8 hf–th–ta diagram for discrimination between basalts from different tectonic settings (after wood, 1980). 166 geologia croatica 57/2 167trubelja, burgath & marchig: triassic magmatism in the area of the central dinarides... it is further observed that the geotectonic specification of samples containing cr-bearing spinel (tiny euhedra crystallized from basaltic melt), and consequently with elevated chromium contents (t3/00/2, t3/00/4) is equivocal (either mid-ocean ridge or arc origin in the discrimination diagrams). figures 9 and 10 show cr vs. ti after garcia (1978) and cr vs. y after pearce et al. (1984), respectively. in both cases several samples including those with a spinel content plot outside the field of volcanic arc basalts. the samples are interspersed with innumerable patches of leucoxene which suggests introduction of ti during alteration. this process could be responsible for the diverging position in the plots of cr vs. ti and cr vs. y. however, fig. 9 cr vs. ti diagram after garcia (1978). the striped line divides the diagram into fields for ocean floor basalts and volcanic arc basalts. fig. 10 cr vs. y diagram after pearce et al. (1984). the field for mid ocean ridge basalts (morb) is framed with a solid line; the field for island arc tholeiites (iat) is framed with a striped line. 168 geologia croatica 57/2 169trubelja, burgath & marchig: triassic magmatism in the area of the central dinarides... it is noticed that ti and y are generally recognized as rather immobile during low-t alteration (e.g. juteau & maury, 1997) and that ti and y are positively correlated in samples t3/00/2 to t3/00/4 (cf. table 2). the leukoxene patches are mainly restricted to chlorite–phyllosilicate-rich interstitial positions which indicate formation via devitrification and thus the elevated contents of these elements are explained as a primary magmatic signature. this is not in contradiction with the classification of the other investigated samples as volcanic arc rocks because a wide range of magmatic rocks, from ridge basalts via iat to calc-alkaline rocks can be associated in zones of former convergent margins, e.g. in semail, oman (beurrier et al., 1989), pindos, greece (beccaluva et al., 1979) or mirdita, albania (gjata, 19973; höck et al., 1998). the spider diagram in fig. 11 shows the average values for basic rocks, and the enrichment of lil elements in comparison to normal morb (saunders & tarney, 1979). this shows that all basic rocks from our investigated area, without exception (individual spider diagrams for every sample not shown), were already changed by additions from the subducted slab although some characteristics of morb are still preserved. the characteristic enrichment of lil elements together with the depletion of hfs elements are also known to be unique for calc-alkaline arc-related volcanic rocks. 6. chemical composition of rocks with higher degree of differentiation figure 12 shows rare earth element patterns normalized on a chondrite basis for four samples which are of a higher degree of differentiation (up to rhyolite with >70% sio2). they also display a similar, but stronger enrichment of lree compared to hree as in the basic rocks. the most differentiated rock (the lowest one on fig. 12) reveals an la/lucn of 15. hitherto, subduction or rifting was suggested as the tectonic setting for the triassic magmatic rocks of the dinarides. generally these settings are both characterised by a wide range of differentiation, but the applied discrimination diagrams are unfortunately limited to basaltic compositions. gorton & schandl (2000) enlarged their use to intermediate and felsic magmatic rocks with sio2 contents from 54–77 wt.% sio2. these enlarged diagrams were developed on the basis of a large collection of rock analyses with known tectonic settings. in fig. 13 four samples with higher sio2 contents of our investigation are plotted. their position is within the field of subduction-induced volcanism, and, furthermore, in the field of active continental margins. 7. conclusions triassic magmatic rocks in the area of the central dinarides in the territory of bosnia and herzegovina are explained as products of subduction-triggered volcanism at an active continental margin (andean type volcanism). the mobility of elements during alteration was tested by means of comparing the compositions of samples with either strong or weak alteration. the use of rather immobile trace elements shows the influence of subducted slab material, including sediments on the investigated magmatic rocks. fig. 11 spider diagram for average of eleven magmatic rocks with sio2<54%, normalized to mid ocean ridge basalts (morb) as suggested by pearce (1983). 3 gjata, k. (1997): an overwiev of the geology and metallogeny of albanian ophiolites.– unpubl. manuscript, albanian geol. survey, 16 p. 168 geologia croatica 57/2 169trubelja, burgath & marchig: triassic magmatism in the area of the central dinarides... 8. references bebien, j., blanchet, r., cadet, j.p., chorowicz, j., laperierre, h. & rampnou, j.p. (1978): le volcanisme triasique des dinarides en yougoslavie: sa place dans l’evolution geotectonique peri-mediterraneenne [triassic volcanism of dinarides in yugoslavia: its place in geotectonical evolution of the perimediterranean – in french].– tectonophysics, 47, 159–176. beccaluva, l., ohnenstetter, d. & ohnenstetter, m. (1979): geochemical discrimination between ocean-floor and island-arc-tholeiites – application to some ophiolites.– can. j. earth sci., 16, 1874–1882. beurrier, m., ohnenstetter, m., cabanis, b., lescuyer, j.l., tegyey, m. & le metour, j. (1989): geochimie des filons doleritiques et des roches volcaniques ophiloitiques de la nappe de semail: contraintes sur leur origine geotectonique au cretace superieur [geochemistry of doleritic bodies and ophiolitic volcanic rocks of the semail nappe: constratins for their geotectonic origin in the late cretaceous – in french].– bull. soc. geol. france, 8, v, 2, 205–219. cissarz, a. (1956): über ein ungewöhnliches magnetitvorkommen am kontakt des gabbromassivs von jablanica in der herzegovina [on extraordinary occurrence of the magnetite on the contact of the jablanica gabbro massif in herzegovina – in german].– ves. zav. geol. geofiz. istr., 12, 201–221, beograd. čelebić, m.d. (1967): geološki sastav i tektonski sklop terena paleozoika i mezozoika izmedju konjica i prozora sa naročitim osvrtom na ležišta fe, mn rude [geological composition and tectonic structure of palaeozoic and mesozoic terrain between konjic and prozor, with special consideration of fe and mn deposits – in serbocroatian].– posebna izdanja geol. glasnika, 10, 1–139, sarajevo. garcia, m.o. (1978): criteria for the identification of ancient volcanic arcs.– earth sci. reviews, 14, 147–165. gorton, m.p. & schandl, e.s. (2000): from continents to island arcs: a geochemical index of tectonic setting for fig. 12 rare earth elements normalized on a chondrite basis (wakita et al., 1971) for four evolved rocks from the investigated area. fig. 13 th/yb vs. ta/yb diagram (after gorton & schandl, 2000) with four evolved rocks from the investigated area which plot in the field of an active continental margin. 170 geologia croatica 57/2 arc-related and within-plate felsic to intermediate volcanic rocks.– can. mineral., 38, 1065–1073. höck, v., koller, f., furtmüller, g. & onuzi, k. (1998): the south-albanian ophiolites in the framework of the dinaric–hellenic ophiolites.– xvi congr. carpathian–balkan geol. assoc., abstract volume, 210. juteau, t. & maury, e. (1997): géologie de la croûte océanique – pétrologie et dynamique endogène [geology of the oceanic crust – petrology and endogenic dynamics – in french].– masson, paris, 367 p. knežević, v., jovanović, v., memović, e. & resimić, k. (1998): trijaske magmatske stene jugoslovenskih dinarida [triassic magmatic rocks of yugoslav dinarides – in serbian].– xiii kongr. geol. jugoslavije, herceg novi, zbornik radova, 3, 61–66. müller, d., rock, n.m.s. & groves, d.i. (1992): geochemical discrimination between shoshonitic and potassic volcanic rocks in different tectonic settings: a pilot study.– mineral. petrol., 46, 259–289. pamić, j. (1984): triassic magmatism of the dinarides in yugoslavia.– tectonophysics, 109, 273–307. pamić, j. & lovrić, a. (1980): geološka i izotopna starost riftnog magmatizma mezozojskog wilsonovog ciklusa dinarida [geological and istopical age of rift magmatism of the mesozoic wilson cycle of the dinarides – in croatian].– simp. region. paleont., 251–260, beograd. pearce, j.a. (1983): role of the sub-continental lithosphere in magma genesis at active continental margins.– in: hawkesworth, c.j. & norry, m.j. (eds.): continental basalts and mantle xenoliths. shiva, nantwich, 230–249. pearce, j.a. & cann, j.r. (1973): tectonic setting of basic volcanic rocks determined using trace element analyses.– earth planet. sci. lett., 19, 290–300. pearce, j.a., lippard, s.j. & roberts, s. (1984): characteristics and tectonic significance of supra-subduction zone ophiolites.– in: kokelaar, b.p. & howels m.f. (eds.): marginal basin geology. blackwell sci. publ. oxford, 77–94. saunders, a.d. & tarney, j. (1979): the geochemistry of basalts from a back-arc spreading centre in the east scotia sea.– geochim. cosmochim. acta, 43, 555–572. trubelja, f. (1978): trijaski magmatiti područja jajca, vakufa, bugojna i kupresa [triassic magmatic rocks of jajce, vakuf, bugojno and kupres area – in croatian].– in: čičić, s. (ed.): geologija bosne i hercegovine, knjiga iv, magmatizam i metalogenija. posebno izdanje geol. glasnika, 39–49, sarajevo. trubelja, f., marchig, v., burgath, k.-p. & höhndorf, a. (2000): initiation of tethys-formation: evidence from triassic magmatic rocks from bosnia and herzegovina.– in: vlahović, i. & biondić, r. (eds.): 2. hrvat. geol. kongres (2nd croatian geological congress), cavtat–dubrovnik, zbornik radova (proceedings), 441–446. wakita, h., rey, p. & schmitt, r.a. (1971): abundances of the 14 rare-earth elements and 12 other trace elements in apollo 12 samples: five igneous and one breccia rocks and four soils.– proc. 2nd lunar sci. conf., pergamon press, oxford, 1319–1329. wood, d.a. (1980): the application of th–hf–ta diagram to problems of tectonomagmatic classification and to establishing the nature of crustal contamination of basaltic lavas of the british tretiary volcanic province.– earth planet. sci. lett., 50, 11–30. manuscript received october 25, 2002. revised manuscript accepted november 08, 2004. lewandowsky.indd 45 �marek lewandowski1,2, ivo velić3, magdalena sidorczuk4, igor vlahović5 and josipa velić5 ab stra ct post-carboniferous deposits of the karst dinarides were analyzed in terms of their palaeomagnetic and rock magnetic properties in order to identify the best sections for comprehensive palaeomagnetic studies on the geodynamic and palaeogeographic evolution of this mountain belt. a total of eighteen reconnaissance rock samples have been collected from the permian red beds and dolomites, and triassic, jurassic, cretaceous and eocene carbonates. most come from velebit mt., part of the dinaric orogenic belt fi nally uplifted in the oligocene–miocene, and stretching nw–se along the ne adriatic coast. experimental studies comprised identifi cation of potential carriers of a natural remanent magnetization (nrm) by means of their properties of curie temperature and coercivity accompanied by sem and microprobe studies, demagnetization of standard palaeomagnetic specimens by means of alternating fi eld and thermal cleaning, as well as the measurement and analysis of magnetic susceptibility and its anisotropy. haematite (in permian red beds) and ti-magnetite (in carbonates) and sporadically goethite have been identifi ed as remanence carriers. the state of preservation, ascertained by sem observations, suggests a detrital origin of nrm in most of the samples. characteristic nrm components (chrm), both of high coercivity and unblocking temperatures, could be clearly identifi ed in most of the specimens. these components show smeared distribution on the sphere and do not cluster around any known palaeomagnetic direction expected for the velebit area from apparent polar wander paths, neither for eurasia nor for africa. this outcome suggests lack of overall remagnetization of the studied part of the karst dinarides after the last tectonic event and/or important contribution from tectonic rotations to the observed pattern of chrm distribution. keywords: palaeomagnetism, rock magnetism, karst dinarides, adria, velebit mt., croatia 1 institute of geophysics, polish academy of sciences, ks. janusza 64, 01-452 warszawa, poland; (lemar@twarda.pan.pl) 2 institute of geological sciences, polish academy of sciences, twarda 51/55, 00-818 warszawa, poland 3 croatian geological survey, sachsova 2, hr-10000 zagreb, croatia 4 faculty of geology, university of warsaw, ul. żwirki i wigury 93, 02-089 warszawa, poland 5 faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, hr-10000 zagreb, croatia first rock magnetic and palaeomagnetic analyses of the pre-cenozoic rocks of the velebit mt. (croatia): prospects for applications in palaeogeographic and geotectonic studies geologia croatica 62/1 45–61 12 figs. 1 tab. zagreb 2009 geologia croaticageologia croatica � geologia croatica geologia croatica 62/1 46 1. introduction mesozoic and cenozoic plate tectonic reconstructions of the carpathian–dinaride–hellenic regions have been recently a matter of several syntheses, involving geologic and palaeomagnetic data (van dijk & scheepers, 1995; neugebauer et al., 2001; stampfli & borel, 2002; csontos & vörös, 2004). the main crustal units of this area are the alcapa, tisza–dacia and adria composite terrains, from which a wealth of palaeomagnetic results have been collected during the past decades (see van dijk & scheepers, 1995; besse & courtillot, 2002; csontos & vörös, 2004; muttoni et al., 2005 for references). a particular gap in this palaeomagnetic data set of adria is due to relatively restricted palaeomagnetic research in the territory of croatia and neighbouring countries, although significant progress has recently been made due to the works of emő márton and co-workers (márton et al., 1995, 1999, 2002, 2003, 2008; see also márton & veljović, 1983). the main purpose of this study was to check the general rock properties of the different units, in order to be able to plan further activities enabling a better insight into a complex tectonic and palaeogeographic evolution of the karst dinarides. therefore, to learn more about the pre-cenozoic history of the croatian part of the adria plate, we performed reconnaissance palaeomagnetic studies in the wider area of velebit mt. in lika and northern dalmatia (fig. 1), which are characterized by rocks of a very wide stratigraphic range. it was particularly important to check a working hypothesis on the possible post-tectonic remagnetization of the velebit structure that would prevent us from undertaking a more indepth palaeomagnetic study on the palaeogeographic and geotectonic evolution of the adriatic carbonate platform and its underlying and overlying units. 2. previous palaeomagnetic studies there has been some previous palaeomagnetic study of the karst dinarides, but the complexity of their geological history requires a systematic approach. in northern croatia, (part of the pannonian basin), somewhat more palaeomagnetic measurements were performed in neogene deposits, including those by márton et al. (1999, 2002, 2006), márton & fodor (2003), babinszki et al. (2007) and vasiliev et al. (2007). most of the previous palaeomagnetic investigations of the karst dinarides were either performed a relatively long time ago (e.g. márton & veljović, 1983; márton & miličević, 1994; kissel et al., 1995; márton et al., 1995), or the area of the karst dinarides was not a major focus of the investigations (e.g. mauritsch et al., 1995; channell, 1996). only recently, have papers on the palaeomagnetic study of the relatively stable areas of the karst dinarides been published by márton et al. (2003, 2008), in which the youngest jurassic, cretaceous and palaeogene rocks were studied. márton et al. (2008) indicate general concordance with the african polar wander path during the youngest jurassic and cretaceous, but with a slight displacement interpreted as a consequence of about 10° ccw rotation of istria in comparison with the african motion. in the earlier paper márton et al. (2003) concluded that the area of stable istria must have been 30° ccw rotated in the tertiary relative to africa and stable europe, but also indicated that maastrichtian–eocene platform carbonates from central dalmatia were subsequently remagnetized, either during the late eocene–oligocene tectonic deformation or by miocene hydrocarbon migration. a recent study by satolli et al. (2008) also indicated coherent movement of adria with respect to africa during the late jurassic and early cretaceous, and the difference in the position of their apparent polar wander paths for this period was interpreted as being a consequence of a subsequent 26° ccw rotation, probably connected with apenninic orogenesis. rocks selected for the purpose of this study have not been, up to our knowledge, palaeomagnetically studied yet. 3. geologic setting the area of the karst dinarides is composed of a thick sequence of deposits, representing a wide stratigraphic range (carboniferous to recent). most of the rocks cropping out in central, western and southern croatia originated from the ancient adriatic carbonate platform, which lasted from the late early jurassic to the end of the cretaceous (see discussion in vlahović et al., 2005). others include the rest of the basement rocks and relatively thin overlying carbonate and siliciclastic deposits. the entire sequence is probably up to 10 km thick, but due to the intense tectonics the thickness may only be estimated. the target rocks, comprising clastics and carbonates of permian to eocene age, crop out in the central part of the karst dinarides (fig. 1). they include thick carbonates and some clastics (fig. 2), deposited in different palaeogeograph ic settings, from mixed siliciclastic–carbonate environments of the epeiric sea to a more or less isolated intraoceanic carbonate platform. palaeogeographic positions varied from equatorial latitudes in the permian to progressively more northern latitudes during the mesozoic and cenozoic. different areas were also submitted to different diagenetic conditions (especially regarding burial depths, which vary from several hundred metres for the youngest to several thousand metres for the oldest rocks). furthermore, it was apparent at the beginning of the investigation that it was necessary to sample rocks of such a wide stratigraphic range (from middle permian to eocene, i.e. from approximately 265 to 50 my) in order to check whether the area of velebit was remagnetized during the important tectonic event connected with the collision and the fi nal uplift of the dinarides. the general succession of deposits in the central part of the karst dinarides, i.e. in the velebit mt. and neighbouring area, is presented in fig. 2. for more information on the succession and its stratigraphy see velić et al., 2002; vlahović et al., 2005; velić, 2007 (and references therein). sampling localities are shown on fig. 1, and logistic data are included in table 1. geologia croaticalewandowski et al.: first rock magnetic and palaeomagnetic analyses of the pre-cenozoic rocks of the velebit mt. (croatia)... 47 fi gu re 1: geographical position of the studied area (a, b – shaded area represents velebit mt.), and schematic geological map (simplifi ed after fgi, 1970) showing the positions of the samples (c). legend: prp – prpići, crn – crne grede, kos – košna, kalv – kalvarija, riz – rizvanuša, bio – biograd, mal – mali halan, otr – otrić, dim – dimići. a b c geologia croatica geologia croatica 62/1 48 fi gu re 2: a schematic geological column of the velebit mt. area illustrating the stratigraphic position of the sampling localities of this study (see fig. 1 for symbols description). time scale after gradstein et al. (2004). palaeogene/neogene events and deposits, which are not a topic of this paper, are presented very simplifi ed. geologia croaticalewandowski et al.: first rock magnetic and palaeomagnetic analyses of the pre-cenozoic rocks of the velebit mt. (croatia)... 49 the oldest sequences of rocks cropping out in the karst dinarides were deposited from the carboniferous to the regional emergence in the early permian, and from the middle permian to the next regional emergence in the middle/late triassic (fig. 2). of these, the oldest cropping out in the area of karst dinarides are the upper carboniferous, (moscovian), predominantly clastic deposits. similar deposition continued into the permian, then after an emergent phase in the early permian, it continued until the end of the middle permian. this part of the sequence was sampled at košna (sample kos) and crne grede (sample crn). a thick succession of carbonates, with only a sporadic and relatively weak input of clastic rocks, is composed of middle/upper permian dolomites (samples kalvarija – kalv, and rizvanuša – riz), lower triassic dolomites and middle triassic recrystallized limestones. all these rocks were deposited in mixed siliciclastic–carbonate environments of the epeiric sea, probably along the ne margins of gondwana (see discussion in vlahović et al., 2005). after a long emergent phase, lasting between the ladinian or early carnian (in places even anisian), until the late norian, a thick succession of pure carbonates was deposited. these represented part of a huge carbonate platform on which regionally important and recognizable facies, including the main dolomite (hauptdolomit) and lithiotis limestones were deposited throughout the area of present southern and southeastern europe, and elsewhere. this sequence, which continued until the end of the early jurassic, was sampled at the prpići locality (sample prp). during the toarcian, the huge former platform was dissected into several small platforms surrounded by drowned basinal areas, including the adriatic carbonate platform which was probably connected towards the south to the kruja, gavrovo–tripolitza and menderes platforms in present albania, greece and turkey. this huge area was isolated from direct continental infl uences because it was surrounded by a deep tethyan ocean, but frequent occurrences of dinosaurs indicate at least temporal connections with africa until the mid-cretaceous, and with eurasia during the late cretaceous, when the platform fi nally disintegrated heralding the beginning of collision with the european plate. this sequence was sampled in mali halan (samples mal), otrić (sample otr) and dimići (samples dim), while the youngest cretaceous rocks (upper santonian) were sampled at biograd (sample bio1). after the shorter or longer emergent phase, deposition was renewed only in the deeper parts of the pre-existing palaeorelief. as a result of intense tectonics, shallow marine, ramp carbonates, (foraminifera limestones – sample bio2), were gradually replaced by deeper-marine fl ysch sediments in elongated basins. regressive promina deposits are only visible in some locations, and end with thick alluvial deposits. the tectonic stress, oriented ne–sw (in present-day geographic coordinates), intensifi ed during the late eocene resulted in the oligocene and early miocene with the intense uplift of the dinarides. this uplift is marked in places by massive tertiary carbonate breccia, while the change of tectonic stress in the younger, neotectonic phase, was charactable 1: basic data for sample collection. legend: s.a. – sample azimuth; s.d. – sample dip; b.a. – bedding azimuth, b.d. – bedding dip. locality hand samples lithology age utm coordinates symbol s.a. s.d. b.a. b.d. x y rizvanuša riz1 294 62 214 85 dolomite u. permian 5524541 4926595 riz2 284 81 208 81 dolomite l. triassic košna kos1 138 52 138 52 red sandstone m. permian 5519453 4929872 kalvarija kalv 128 50 205 89 dolomite u. permian 5521786 4928382 crne grede crn1 10 120 190 60 red sandstone m. permian 5517390 4929628 prpići prp1 111 70 240 10 dolomite norian 5512127 4932680 mali halan mal1 6 51 202 40 limestone hettangian 5552426 4905346 mal2 10 135 190 55 limestone pliensbachian 5552337 4904942 mal3 120 123 197 57 limestone toarcian 5551459 4904986 mal4 50 131 230 49 limestone m. jurassic 5551437 4904819 mal5 101 0 225 69 limestone oxfordian 5551705 4903297 mal6 216 70 216 70 limestone kimmeridgian 5551512 4902925 otrić otr1 305 75 76 37 limestone m. jurassic 5586321 4899795 dimići zapad dim1 220 73 39 23 limestone callovian 5588429 4898868 dim2 348 16 57 10 limestone oxfordian 5588726 4899063 dim3 46 15 71 11 limestone kimmeridgian 5588878 4899184 biograd bio1 230 42 210 55 limestone u. santonian 5537087 4866758 bio2 232 114 232 55 limestone l. eocene 5537089 4866756 geologia croatica geologia croatica 62/1 50 terized by a n–s oriented stress and mostly stike-slip movements, which fi nally shaped the karst dinarides. 4. analytical procedures eighteen magnetically oriented hand samples, treated as a reconnaissance collection, were taken from rocks of varied ages from the permian to the eocene (table 1). hand samples were cored in the laboratory into standard palaeomagnetic cores, 1” diameter, yielding a total of 59 cores. of these, 48 cores yielded sound palaeomagnetic results, enabling the identifi cation of components of the natural remanent magnetization (nrm). stable, characteristic components of nrm (chrm) were used for the preliminary as sessment of the relative rotations of the succession from the velebit area with respect to eurasia and africa. the magnetic mineralogy was assessed using the method of lowrie (1990), supported by sem and microprobe studies for better understanding of the nature of nrm. the lowrie test was performed on standard-sized specimens, which were initially stepwise pulse magnetized along the z axis up to 2.7 mt to obtain the coercivity characteristics in a form of an induced remanent magnetization (irm) curve. next, the same specimens were pulse magnetized along the z, y and x axes in nominal fi elds of 2.7, 0.4, and 0.12 mt, respectively (lowrie, 1990), and, subsequently subjected to thermal demagnetization, providing information on unblocking temperatures (néel temperature, tub) for each of the irm three -components. changes in the low-fi eld susceptibility (κ) during the thermal demagnetization experiment were routinely monitored using the low-fi eld kly–2 susceptibility bridge. variation of the initial magnetic susceptibility along the lithostratigraphic column was used to infer changes of paramagnetic minerals infl ux into the sedimentary basin. the anisotropy of the magnetic susceptibility (ams) of 75% of the specimens was measured, and the density distribution of the principal components of the ams ellipsoids was calculated using the spheristat package (stesky, 1995). ams study was performed to check the potential effects on internal rock deformation induced by tectonic stress (see tarling & hrouda, 1993). all cores were subjected to thermal demagnetization in a magnetic minerals mm–1 furnace. each specimen was heated in steps up to 580°c, except for the haematite-bearing rocks, which were heated up to 670°c. after each demagnetization step, cores were cooled in a zero magnetic fi eld and measured on a 2g squid cryogenic magneto meter with a residual internal fi eld below 3 nt and a noise level of less than 10–7 a/m (compared to 2 x 10–6 a/m of the most advanced spinner magnetometers). these characteristics ensure the complete demagnetization of the sampled rocks and identifi cation of the most subtle nrm components, preventing unfavourable mineralogical changes in a course of thermal demagnetization. the cores exhibiting spurious magnetization and/or an nrm intensity close to the magnetometer noise level were excluded from the demagnetization procedure. both the furnace and the squid magnetometer were operated inside a pair of helmholz coils, reducing the ambient geomagnetic fi eld by at least 95%. some specimens were demagnetized by means of alternating fi eld (af), using magnetically shielded solenoids, combined with the squid. palaeomagnetic data analysis (pda) software by lewan dowski et al. (1997), employing principal component analysis (kirschvink, 1980), was used to calculate the characteristic nrm components (chrm) from the demagnetization data of each specimen, and to plot the orthogonal demagnetization diagrams. chrm components with angular standard deviation greater than 8° were exclud ed from further analysis. standard fisher (1953) statistics were used to calculate the characteristic mean direction for the remaining chrm populations. gmap by torsvik & smethurst (1999) has been used for recalculation of the palaeomagnetic directions from apparent polar wander paths (apwp). the rock samples (approximately 2 kg each) were dissolved in acetic acid (cf. hounslow & maher, 1999), and magnetic minerals were extracted from the insoluble fraction by a neodymium magnet placed in a removable, thin latex envelope. the extracts were analyzed by scanning electron microscope with edx, jeol jsm–6380la. thin sections were analyzed by electron microprobe with a cameca wdx sx 100 device in order to identify the chemical composition of ferrimagnetic grains. 5. results 5.1. rock magnetic results rock magnetic studies revealed the presence of both soft and hard magnetic phases in the studied rocks. permian red beds of the košna unit (fig. 3a) do not contain any magnetite. specimens were not saturated up to the fi eld of 2.7 mt, and the maximum of tub for each of three induced components was in the range of 670°c, unequivocally demonstrating the presence of haematite. in contrast to the košna deposits, the upper permian limestones of rizvanuša (fig. 3b) contain a mixture of low and very high coercivity mineral phases. it is clearly demonstrated by the bimodal trend of the irm curve, showing a steep slope up to the 0.2 t fi eld, followed by a remanence plateau up to 0.9 mt, and continued by a gradual increase of the remanence, yet not saturated in the highest fi eld. the presence of two different magnetic phases is confi rmed by the lowrie test, where the hard magnetic phase has a tub of ca. 670°c, while the soft one shows a tub of the order of 540°c, implying the presence of haematite and ti-poor magnetite, respectively. callovian limestones of dimići (fig. 3c) show the presence of a single magnetic phase with a low coercivity, easily saturated with the magnetic fi eld of 0.2 t. this phase shows a tub around 540°c, characteristic for tipoor magnetite. upper santonian carbonates of biograd (fig. 3d) show an irm arcuate shaped curve up to the highest imposed magnetic fi eld. this is indicative for the presence of a hard coercivity mineral, which was still unsaturated in the fi eld of 2.7 t. thermal demagnetization shows a low unblocking geologia croaticalewandowski et al.: first rock magnetic and palaeomagnetic analyses of the pre-cenozoic rocks of the velebit mt. (croatia)... 51 fi gu re 3: results of the lowrie test of typical samples. induced remanence acquisition curves (left plots) and thermal demagnetization of the remanence induced along z (triangles), y (open circles) and x (full circles) specimens axes (right plots). see text for more detailed descriptions of diagrams. a b c d geologia croatica geologia croatica 62/1 52 temperature for the high coercivity phase (tub ca. 150°c), coexisting with a phase of tub near 580°c, characteristic for goethite and magnetite, respectively. 5.2. susceptibility results magnetic susceptibility varied from site to site, and generally, three groups of susceptibilities can be distinguished (fig. 4a): group l, with very low values, ranging from –12.78 to +4.61x10–6 si, group i with intermediate susceptibilities (+30.9 to +84.9x10–6 si), and group h, characterized by high susceptibilities (from +109.7 to +194.2x10–6 si). group l has susceptibilities comparable with typical platform carbonates, with a very low content of ferrimagnetic grains, while group i has values comparable with the susceptibilities of pelagic limestones (cf. lewandowski et al., 2005). group i comprises the upper permian and lower triassic rocks, as well as the middle jurassic carbonates. group h comprises carbonate deposits spanning the upper triassic to the lower parts of the middle jurassic, having susceptibility values comparable with the red beds of the middle permian age. older and younger carbonates all display the l category of susceptibility. anisotropy of magnetic susceptibility is of generally low values (fig. 4b), which is rather an unexpected result for the rocks relatively strongly affected by tectonics. the degree of anisotropy (pj, jelinek, 1981) does not generally exceed 3%. the exception are rocks of crne grede and otrić (middle permian and the middle jurassic age, respectively), both having the l category of susceptibility. their pj values indicate a strongly developed foliation (fig. 4b), for the deformation of sphere exceeding 10%, up to 40% with a positive value of the shape parameter t (jelinek, 1981). these data indicate an increased degree of internal deformation of rocks of crne grede and otrić sites, located close to the major fault and regional nappe system margin, respectively, although a heightened infl ux of clay minerals to the sedimentary basin may also be important. 5.3. sem and electron microprobe results insoluble residuals of velebit mt. carbonates contain a variety of magnetic fractions. the most interesting for study were those magnetic phases with the potential of representing remanence carriers. most of the identifi ed magnetic grains of this group were magnetites/ti-magnetites, with different fi gu re 4: (a) variation of the magnetic susceptibility parameter κ; (b) anisotropy of the magnetic susceptibility – variability of magnetic foliation pj (jelinek, 1981). ranges of categories of susceptibilities are shown: l (low) – light grey, i (intermediate) – medium grey, and h (high) – dark grey. a b geologia croaticalewandowski et al.: first rock magnetic and palaeomagnetic analyses of the pre-cenozoic rocks of the velebit mt. (croatia)... 53 ti contents. the gain shapes frequently indicate a detrital origin, with sharp edges possibly indicating proximal sour ces. grains with rounded edges suggest more distal transport, but some diagenetic infl uence due to dissolution by reducing fl uids cannot be excluded. spheres of diagenetic mag netite/ maghemite with an exclusive iron composition, probably after pyrite replacement, were also observed, as well as framboidal pyrite spheres formed by aggregated subcrystals. grain dimensions, on average, span between pseudo-singledomain states (dozen µm) to multidomain grains (>20 µm). typical examples are shown in figs. 5–7. 5.4. palaeomagnetic results the overall mean nrm measured for 45 specimens has the orientation d=14o, i=51o (present-day coordinates – fig. 8), and is very similar to the present-day direction of the regional geomagnetic vector, expected for the mean sampling localities coordinates of 45°n/15°e from the geocentric, axial dipole model (d=0o, i=63o). this result proves that sample orientations were correct and that the present-day geomagnetic vector may have had an important contribution to the total remanence acquired in the rocks of the velebit area. fi gu re 5: (a) well sorted, detrital ti-poor magnetite (mal3–3), indicative of a distal source; (b) ti-poor magnetite (mal5–5) and magnetite spherule (mal5–6) of a pseudo-single-domain dimension, potential carrier of a stable nrm (lower jurassic carbonates, mali halan). a b geologia croatica geologia croatica 62/1 54 5.4.1. results of alternating fi eld demagnetization most of the specimens responded very well to af cleaning due to the presence of ti-magnetite, although chaotic trends in demagnetization curves could also be encountered. the middle permian limestones of crne grede (fig. 9a) show a two-component structure of nrm. while the initial intensity is very low, the specimen could be successfully demagnetized almost to null values of the magnetization intensity. a low coercivity component is close to the present-day geomagnetic vector at the sampling site and can be regarded as a contemporary overprint. the stable component, identifi ed in the range of 25–40 mt, has a northerly direction with a shallow inclination (geographical coordinates, fig. 9a). upper permian limestones of kalvarija (fig. 9b) show a similar nrm structure, but due to a stronger (by an order of magnitude) initial value of nrm, its components could be much more precisely determined. the lower triassic limestones of rizvanuša (fig. 9c) mainly show a zigzag demagnetization trend, except for a soft, steeply inclined component. the upper triassic limestones of prpići (fig. 9d) contain two components with similar orientation toward the north and moderate inclination. the nonlinear shape of the demagnetization path indicates overlapping coercivity spectra, which makes precise identifi cation of these components impossible. middle jurassic limestones of the mali halan section (fig. 9e) show generally nonlinear demagnetization paths, characteristic for components with overlapping coercivity spectra. nonetheless, linear segments of demagnetization trajectories can be seen, enabling identifi cation of two chrm components. the soft one is directed along the ambient, present-day geomagnetic vector, while the harder component points to the north with intermediate inclination (geographical coordinates, fig. 9e). middle jurassic limestones from otrić (fig. 9f) also have a bimodal nrm structure and similar characteristics to those from the mali halan. similarly, the inclination of the chrm component is steeper than within permian carbonates. kimmeridgian limestones of dimići (fig. 9g) contain two components of nrm. the soft one (up to 15 mt) is of fi gu re 6: (a) magnetite grain of callovian carbonates of dimići; dim1–1 iron oxide (magnetite?), incorporated into a group of clay minerals; (b) dim1–3 detrital iron oxide, probably magnetite, with attached surface coats of clay minerals, as indicated by eds spectra. a b geologia croaticalewandowski et al.: first rock magnetic and palaeomagnetic analyses of the pre-cenozoic rocks of the velebit mt. (croatia)... 55 fi gu re 7: poorly sorted, ti-magnetite grains of the upper santonian carbonates (biograd). (a) bio1–1 ti-rich magnetite grain, bio1–2 magnetite(?) and bio1–3 an unidentifi ed mineral phase containing bi; (b) bio1–9 magnetite exhibiting sharp edges, suggesting detrital origin from a proximal source. a b geologia croatica geologia croatica 62/1 56 viscous, present-day origin, while the stable, higher coercivity component of reversed polarity shows a ssw orientation with shallow inclination (after tectonic correction, fig. 9g). a good example of the chaotic trends in demagnetization is the specimen of the eocene limestones of biograd (fig. 9h). santonian limestones of the same locality, however, show linear trends enabling determination of two nrm components, while the third component resides in a hard coercivity phase and it cannot be resolved by af demagnetization (fig. 9i). 5.4.2. results of thermal demagnetization middle permian košna red beds were not treated by the af method, since only haematite has been identifi ed by the lowrie test. thermal demagnetization (fig. 10a, b) reveals a bimodal structure of nrm with the characteristic remanence component pointing nwn with rather shallow inclination (geographic position). in general, thermal cleaning was also fairly effective in revealing nrm composition, although the af method seemed to be better in some cases. for instance, thermal demagnetization of middle permian crne grede limestones (fig. 10c) yielded a rather poorly defi ned component residing in grains of moderate tub (150–350°c). although a general direction of chrm is similar to the one identifi ed by af (fig. 9a), the quality of the latter is defi nitively higher. also, thermal cleaning of the upper permian carbonates of kalvarija was less effective than af demagnetization (cf. fig. 10d and fig. 9b) and yielded results that could not be interpreted. upper permian carbonates of rizvanuša (fig. 10e) show weak magnetization. despite low reliability due to higher a.s.d. values (up to 10°), chrm orientations are relatively coherent at the sample level. maximum tub suggests a timagnetite carrier of nrm, and do not confi rm the presence of haematite, ascertained by the lowrie test. this may be a result of the inhomogeneous distribution of haematite in these rocks. a steep, generally southwesterly directed chrm (palaeohorizontal) could be determined, which makes thermal cleaning more successful than af in this case. thermal cleaning was quite effective in the case of the middle triassic prpići rocks (fig. 10f), where nrm components could, in contrast to af cleaning, be isolated due to the linear trajectories of the demagnetization paths. values of 500°c for maximum tub suggest the presence of ti-magnetite. upper jurassic limestones of dimići (fig. 10g) respond ed fairly well to thermal cleaning, despite a low intensity of nrm. maximum tub is around 475°c, suggesting ti-magnetite as the main remanence carrier. chrm show a northeasterly orientation with moderately shallow inclination (geographical coordinates, fig. 10g) and is similar to the chrm obtained by the af method. mali halan limestones (fig. 10h, i) show a similar nrm structure, recorded in rock samples collected at different sites. a stable chrm component shows a moderately steep, northerly orientation, in line with results obtained from the af method. this component features tub of ca. 450°c, suggesting the presence of ti-magnetite. results obtained from the rocks of otrić (fig. 10j) are again essentially the same as for the af method, both in the shape of the demagnetization path and in the direction of chrm. despite a very weak remanence, thermal cleaning could be performed down to the squid noise level, since, fortunately, no secondary magnetic phases were formed in the course of thermal cleaning. a maximum tub of ca. 450°c is indicative of ti-magnetite grains. thermal demagnetization of the santonian limestones of biograd (fig. 10k) yielded only one component, in contrast to the three components of nrm ascertained by means of af cleaning. a thermal demagnetization diagram demonstrates a straight line segment for almost the whole range of temperatures, thus indicating the presence of a single component. notably, specimens treated with temperature show a component of opposite polarity to that demagnetized by af. 5.4.3. chrm directions – a general interpretation a small number of independently oriented samples per stratigraphic site exclude any reliable calculation of overall characteristic directions and a virtual palaeopole position for each sampled unit. this, however, does not preclude a general interpretation of all individually isolated chrms, based on their comparison with a reference path of palaeomagnetic directions expected for the studied area, on the basis of an assumption on the structural coherence of the velebit mt. rocks either with gondwanian or european crust. the reference path (rp) can be established by recalculation of postcarboniferous palaeopoles of gondwana and eurasia (data for carboniferous and triassic after van der voo (1993), and from besse & courtillot (2002) for younger geologic ages) at the reference site (coordinates 45°n, 15°e), as fi gu re 8: distribution of nrm direction, measured for undemagnetized spe cimens. open/full symbols represent upper/lower hemisphaere, present-day geomagnetic fi eld vector (pdf) is marked by a grey triangle. overall mean (marked by crossed dot) with associated α95 confi dence limit is shown for comparison with pdf direction. geologia croaticalewandowski et al.: first rock magnetic and palaeomagnetic analyses of the pre-cenozoic rocks of the velebit mt. (croatia)... 57 fi gu re 9: results of af demagnetization of typical samples (see text for sample locations and age). the plots are equal area, orthogonal (zijderveld), and normalized intensity decay of induced remanent magnetization. open/full symbols represent the upper/lower stereonet hemisphaere, squares/ circles at zijderveld plots denote projections onto horizontal/vertical planes. units on the orthogonal plots are in μa/m. a b c d e f g h i geologia croatica geologia croatica 62/1 58 fi gu re 10: (continued on the next page) a b c d e f g h geologia croaticalewandowski et al.: first rock magnetic and palaeomagnetic analyses of the pre-cenozoic rocks of the velebit mt. (croatia)... 59 shown in the fig. 11. in the fig. 12, in turn, chrm directions are depicted both in their geographic coordinates (i.e. before correction for tilt) and in a palaeohorizontal frame (i.e. after correction for tilt), to be confronted with rps. in the palaeohorizontal frame (fig. 12b), most chrm vectors show steep inclinations, incompatible with the known palaeogeographic history of adria, which remained constantly at equatorial to moderate palaeolatitudes during mesozoic– cenozoic time (dercourt et al., 2000; golonka, 2000). we suppose, therefore, that these directions do not represent primary nrm components. in the geographic frame (fig. 12a), however, the permotriassic deposits of košna, crne grede, rizvanuša, and kalvarija show low-to-moderate inclinations and smeared declinations within the nnw–ene sector, rotated at a different degree from the coeval directions of the rps of africa and eurasia. the same applies to the middle jurassic rocks of mali halan and dimići. in general, fig. 12 depicts a scattered distribution of chrm vectors, meaning that there was no common post-tectonic remagnetization of all the studied rocks. although the monoclinal structure of the investigated strata precluded fold tests, the smeared distribution of the characteristic components suggests an important, tectonic involvement of the rocks in question, the nature and meaning of which remains an open question. future investigations will therefore focus on more detailed palaeomagnetic and rock-magnetic studies of available fold structures along the range of velebit mt. and their timeequivalent rocks in the south-easternmost part of croatia. these planned studies should help in the identifi cation of primary (pre-folding) and secondary nrm components, making the geotectonic history of dinarides better bracketed in the palaeogeographic frame. 6. conclusions taking into account the results obtained in this study, the following conclusions can be drawn: fi gu re 11: outline of palaeomagnetic reference directions, recalculated for the site 45°n/15°e (gospić area, velebit mt.) from current apwps for africa and eurasia (see text for details). legend: open/full symbols and broken/solid line represent upper/lower hemisphere, respectively; c3 – upper carboniferous, p – permian, t – triassic, j – jurassic, k – cretaceous, tr – tertiary. fi gu re 10: results of thermal demagnetization (continued from the previous page). see fig. 9 for symbols explanation. i j k geologia croatica geologia croatica 62/1 60 (1) in most cases, rocks of velebit mt. yielded interpretable palaeomagnetic results. (2) the area of velebit mt. was not completely remagnetized during the latest (neogene) tectonic event, since chrms do not exhibit a normal (fisherian) distribution around the palaeomagnetic direction, expected for the velebit region in the neogene. (3) the upper triassic to middle jurassic deposits show a higher magnetic susceptibility than older and younger rocks. this may be attributed to a higher infl ux of magnetic grains due to geotectonic and volcanic processes, initiated by the break up of pangea. (4) ti-magnetite and haematite were the principal magnetic carriers; most of the grains are of detrital origin. (5) both af and thermal cleaning were effi cient for isolation of nrm components. (6) af cleaning yielded particularly good results for the upper triassic of prpići, the upper permian of kalvarija and the middle jurassic of mali halan. (7) thermal demagnetization was particularly successful for the upper triassic of prpići and the callovian limestones of dimići. (8) the characteristic components obtained for permo-triassic and middle jurassic rocks display declinations within the nnw to ene sector with moderate to shallow inclinations, when observed in geographical coordinates. such overall distributions, compared with the expected direction for adria in mesozoic–cenozoic time, suggest tectonic rotations with respect to gondwana. acknowledgement this paper resulted from the bilateral polish–croatian interacademic project ‘palaeogeographic history of the adria plate: palaeomagnetic reconstruction’ (2007–2009, principal investigators marek lewandowski and igor vlahović), and the work was supported by the host institutions of marek lewandowski and the ministry of science, education and sports of the republic of croatia through grants 195-1953068-0242, 195-1953068-2704 and 195-1951293-0237. the study was partly supported by the faculty of geology, university of warsaw (projects no. bw 1761/2 and bst 1331/2). the authors are grateful to niels abrahamsen and jerzy naw rocki for their constructive suggestions on the fi rst version of this paper. references babinszki, e., márton, e., márton, p. & kiss, l.f. (2007): widespread occurrence of greigite in the sediments of lake pannon: implications for environment and magnetostratigraphy.– palaeogeogr., palaeoclimatol., palaeoecol., 252, 626–636. besse, j. & courtillot, v. (2002): apparent and true polar wander and the geometry of the geomagnetic fi eld over the last 200 myr.– j. geophys. res., 107, (b11), 2300, doi: 10.1029/2000jb000050. channell, j.e.t. (1996): palaeomagnetism and palaeogeography of adria.– in: morris, a. & tarling, d.h. (eds.): palaeomagnetism and tectonics of the mediterranean region. geological society of london, spec. publicat., 105, 119–132. csontos, l. & vörös, a. (2004): mesozoic plate tectonic reconstruction of the carpathian region.– palaeogeogr., palaeoclimatol., palaeoecol., 210, 1–56. dercourt, j., gaetani, m., vrielynck, b., barrier, e., biju-duval, b., brunet, m.f., cadet, j.p., crasquin, s. & sandulescu, m. (eds.) (2000): peri-tethys palaeogeographical atlas.– commision for the geological map of the world, paris. fisher, r. (1953): dispersion on the sphere.– proc. r. astron. soc., a217, 295–305. fgi (1970): geological map of sfr yugoslavia 1:500,000.– federal geological institute, beograd. golonka, j. (2000): cambrian–neogene plate tectonics maps.– wydawnictwo uniwersytetu jagiellońskiego, kraków. gradstein, f.m., ogg, j.g., smith, a.g., agterberg, f.p., bleeker, w., cooper, r.a., davydov, v., gibbard, p., hinnov, l.a., house, m.r., lourens, l., luterbacher, h.p., mcarthur, j., melchin, m.j., robb, l.j., shergold, j., villeneuve, m., wardlaw, b.r., ali, j., brinkhuis, h., hilgen, f.j., hooker, j., howarth, r.j., knoll, a.h., laskar, j., monechi, s., plumb, k.a., powell, j., raffi, i., röhl, u., sadler, p., sanfilippo, a., schmitz, b., shackleton, n.j., shields, g.a., strauss, h., van dam, j., van kolfschoten, t., veizer, j. & wilson, d. (2004): a geologic time scale 2004.– cambridge university press, 589 p. hounslow, m.w. & maher, b.a. (1999): laboratory procedures for quantitative extraction and analysis of magnetic minerals from sediments.– in: walden, j., oldfield, f. & smith, j. (eds.): environmental magnetism, a practical guide. quaternary research association, technical guide, 6, 139–164. jelinek, v. (1981): characterization of the magnetic fabric of rocks.– tectonophys., 79, 63–67. fi gu re 12: characteristic remanent magnetization in geographic (a) and palaeohorizontal (b) frame, obtained in this study. note the lack of a distinctive direction governing overall vector distribution. dots/ squares are directions obtained due to thermal/af cleaning, respectively. other symbols are explained in the fig. 8. a b geologia croaticalewandowski et al.: first rock magnetic and palaeomagnetic analyses of the pre-cenozoic rocks of the velebit mt. (croatia)... 61 kirschvink, j.l. (1980): the least-square line and plane and the analysis of paleomagnetic data.– geophys. j. r. astr. soc., 62, 699–718. kissel, c., speranza, f. & miličević, v. (1995): paleomagnetism of external southern and central dinarides and northern albanides: implications for the cenozoic activity of the scutari–peć transverse zone.– j. geophys. res., 100, 14999–15007. lewandowski, m., werner, t. & nowożyński, k. (1997): pda: a package of fortran programs for paleomagnetic data analysis. program manual.– inst. geoph., pol. acad. sc., warsaw, poland. lewandowski, m., krobicki, m., matyja, b.a. & wierzbowski, a. (2005): palaeogeographic evolution of the pieniny klippen basin using stratigraphic and paleomagnetic data from the veliky kamenets section (carpathians, ukraine).– palaeogeogr., palaeoclimatol., palaeoecol., 216, 53–72. lowrie, w. (1990): identifi cation of ferromagnetic minerals in a rock by coercivity and unblocking temperature properties.– geophys. res. lett., 17/2, 159–162. márton, e. & fodor, l. (2003): tertiary paleomagnetic results and structural analysis from the transdanubian range (hungary): rotational disintegration of the alcapa unit.– tectonophys., 363, 201–224. márton, e. & miličević, v. (1994): tectonically oriented paleomagnetic investigation in the dinarids, between zadar and split.– geophys. transact., 39/4, 227–232. márton, e. & veljović, d. (1983): paleomagnetism of the istria peninsula, yugoslavia.– tectonophys., 91, 73–87. márton, e., drobne, k., cimerman, f., ćosović, v. & košir, a. (1995): paleomagnetism of latest maastrichtian through oligocene rocks in istria (croatia), the karst region, and s of the sava fault (slovenia).– first croatian geological congress, proceedings, institute of geology, zagreb, 2, 355–360. márton, e., pavelić, d., tomljenović, b., pamić, j. & márton, p. (1999): first paleomagnetic results on tertiary rocks from the slavonian mountains in the southern pannonian basin, croatia.– geol. carpat., 50/3, 273–279. márton, e., pavelić, d., tomljenović, b., avanić, r., pamić, j. & márton, p. (2002): in the wake of a counterclockwise rotating adriatic microplate: neogene paleomagnetic results from northern croatia.– int. j. earth sci. 91, 514–523. márton, e., drobne, k., ćosović, v. & moro, a. (2003): paleomagnetic evidence for tertiary counterclockwise rotation of adria.– tectonophys., 377, 143–156. márton, e., jelen, b., tomljenović, b., pavelić, d., poljak, m., márton, p., avanić, r. & pamić, j. (2006): late neogene counterclockwise rotation in the sw corner of the pannonian basin.– geol. carpat., 57/1, 41–46. márton, e., ćosović, v., moro, a. & zvocak, s. (2008): the motion of adria during the late jurassic and cretaceous: new paleomagnetic results from stable istria.– tectonophys., 454, 44–53. mauritsch, h.j., scholger, r., bushati, s.l. & ramiz, h. (1995): palaeomagnetic results from southern albania and their signifi cance for the geodynamic evolution of the dinarides, albanides and hellenides.– tectonophys., 242, 5–18. muttoni, g., erba, e., kent, d.v. & bachtadse, v. (2005): mesozoic alpine facies deposition as a result of past latitudinal plate motion.– nature, 434 (7029), 59–63. neugebauer, j., greiner, b. & appel, e. (2001): kinematics of the alpine–west carpathian orogen and palaeogeographic implications.– j. geol. soc. london, 158, 97–110. satolli, s., besse, j., speranza, f. & calamita, f. (2007): the 125–150 ma high-resolution apparent polar wander path for adria from magnetostratigraphic sections in umbria–marche (northern apennines, italy): timing and duration of the global jurassic–cretaceous hairpin turn.– earth planet. sci. lett., 257, 329–342. stampfli, g.m. & borel, g.d. (2002): a plate tectonic model for the paleozoic and mesozoic constrained by dynamic plate boundaries and restored synthetic oceanic isochrones.– earth planet. sci. lett., 196, 17–33. stesky, r.m. (1995): spheristat 2.0. for windows 3.1. users manual.– pangea scientifi c, brockville, ontario, canada. tarling, d.h. & hrouda, f. (1993): the magnetic anisotropy of rocks.– chapman & hall, london, 217 p. torsvik, t.h. & smethurst, m.a. (1999): plate tectonic modeling: virtual reality with gmap.– computers & geosciences, 25, 395–402. van der voo, r. (1993): paleomagnetism of the atlantic, tethys and iapetus oceans.– cambridge university press, cambridge, 411 p. van dijk, j.p. & scheepers, p.j.j. (1995): neotectonic rotations in the calabrian arc: implications for a pliocene–recent geodynamic scenario for the central mediterranean.– earth sci. rev., 39, 207– 246. vasiliev, i., bakrač, k., kovačić, m., abdul aziz, h. & krijgsman, w. (2007): palaeomagnetic results from the sarmatian/ pannonian boundary in north-eastern croatia (vranović section, našice quarry).– geol. croat., 60/2, 151–163. velić, i. (2007): stratigraphy and palaeobiogeography of mesozoic benthic foraminifera of the karst dinarides (se europe).– geol. croat., 60/1, 1–113. velić, i., vlahović, i. & matičec, d. (2002): depositional sequences and palaeogeography of the adriatic carbonate platform.– mem. soc. geol. ital., 57, 141–151. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeogr., palaeoclimatol., palaeoecol., 220, 333–360. manuscript received october 1, 2008 revised manuscript accepted january 23, 2009 geo.cro.2-3-61-kb.pdf 297 � ioan i. bucur1, bruno granier2 and emanoil săsăran1 ab stra ct a study of calcareous strata previously assigned to the barremian-early aptian interval in the northwestern part of pădurea craiului, (apuseni mountains), led to the identifi cation of a micropaleontological association indicative of a late aptian age. unequivocal evidence for the late aptian assignment of these limestones is the presence throughout the sequence of two orbitolinid species, mesorbitolina texana (roemer) and mesorbitolina subconcava (leymerie). the most interesting sections are located in the neighbourhood of subpiatră, where both outcrops and a quarry facilitated detailed analyses. in this area, the upper aptian succession consists basically of three types of macrofacies: 1) limestone with rudists; 2) limestone with bacinella and 3) limestone with corals, each of them showing several types of microfacies. bacinella structures are the most common feature in the whole succession, irrespective of the macrofacies. this paper focuses on an algal association that was identifi ed in several levels within the succession. dasycladalean algae are more frequent, and are commonly found in grain-dominated fabrics (mostly grainstone textures), in association with orbitolinid foraminifera and bioclasts of corals, rudists and gastropods. however, a few species are present only in mud-dominated fabrics (i.e. lower-energy intervals). the dasycladalean association from the upper aptian deposits of pădurea craiului is of special interest, for this group registered a dramatic decline at the lower aptian/upper aptian boundary, as confi rmed by the relative scarcity of the dasycladales in the upper aptian carbonate deposits. keywor ds: calcareous algae, upper aptian, pădurea craiului, apuseni mountains, romania 1 department of geology, center of geological integrated studies, babeş-bolyai university, str. m. kogălniceanu nr.1, 400084 cluj-napoca, romania; ( ibucur@bioge.ubbcluj.ro; esasaran@bioge.ubbcluj.ro) 2 département des sciences de la terre, ufr des sciences et techniques, université de bretagne occidentale (ubo), 6, avenue le gorgeu, f-29238 brest cedex 3, france; (bgranier@univ-brest.fr) upper aptian calcareous algae from pădurea craiului (northern apuseni mountains, romania) geologia croatica 61/2–3 297–309 3 figs. 3 pls. zagreb 2008 geologia croaticageologia croatica � 1. introduction, stratigraphic framework the pădurea craiului massif includes mesozoic deposits of triassic, jurassic and cretaceous age. samples were collected from several profi les in the subpiatră quarry (near the aleşd locality, in the northwestern part of the pădurea craiului mountains (fig. 1) and were assigned into the local cretaceous succession. the lowermost cretaceous strata lie unconformably on a surface deformed by regional uplift at the end of the upper jurassic. the sequence begins with bauxites that are overlain by carbonate deposits assigned to discrete lithostratigraph ic units, from bottom to top as follows (fig. 2): 1) blid formation (dragastan et al., 1986, 1988). this formation includes two members (cociuba, 2000): 1. a) the dobreşti member overlies bauxites or rests directly on upper jurassic limestone. originally, the basal limestone of the dobreşti member contains lacustrine deposits, which are followed by brackish and fi nally by normal marine strata; in the literature they are known as “limestone with characeans and gastropods” (patrulius in ianovici et al., 1976). besides characeans and gastropods, this limestone con tains dasycladalean algae and foraminifera, an assemblage geologia croatica geologia croatica 61/2–3 298 with a low value regarding its stratigraphic resolution that however indicates a berriasian–hauterivian range. 1. b) the coposeni member, previously known as the “lower pachyodont limestone” (patrulius in ianovici et al., 1976), is upper hauterivian-barremian in age. the foraminiferal association identifi ed in the lower middle part of this limestone contains paracoskinolina? jourdanensis (foury & moullade), an index foraminifer for the upper hauterivian p.p. and lower barremian. 2) ecleja formation (patrulius, in ianovici et al., 1976), a succession of greyish silty marls to marly silts. it includes two members that differ in lithology from the marly succession (cociuba, 2000): 2. a) the gugu breccia member (patrulius et al., 1982) and 2. b) the valea bobdei limestone member (cociuba, 2000). the valea bobdei limestone was known previously as “the middle pachyodont limestone”. most probably, its age is basal early aptian (early bedoulian). 3) the valea măgurii limestone formation (cociuba, 2000) rests on the ecleja marls and its upper limit is the site of an unconformity. this formation is also of early aptian age (most probably late bedoulian). both the valea bobdei limestone and the valea măgurii limestone include the orbitolinid palorbitolina lenticularis (blumenbach), a fossil that ranges from the late barremian to the early aptian. 4) the vârciorog formation (cociuba, 2000) is the new designation for the previously defi ned “formation of the glauconitic sandstones and the upper pachyodont limestones” (patrulius in ianovici et al., 1976). in the varciorog area, the limestone interbeds are 15–20 m thick and contain mesorbitolina texana. the vârciorog formation was assigned to the upper aptian (gargasian) – albian interval. the limestone of the subpiatră quarry belongs to this same formation. a section in the southern part of the study area was the object of a preliminary investigation (daoud et al., 2004). 2. carbonate facies and age of the vârciorog formation limestone macroscopically, three major facies could be identifi ed: biostromes with rudists, limestone with bacinella nodules and coral bioconstructions with their associated unique facies (fig. 3). their study under the microscope showed several types of microfacies all characterized by an abundance of bacinella, (its occurrence is most conspicuous in a bindstone with bacinella, and in a bioclastic wackestone-packstone with bacinella oncoids), followed by somewhat lesser quantities in wackestone-packstone and coarse bioclastic grainstone, packstone and boundstone with rudists, coral boundstone and peloidalbioclastic wackestone-packstone (pl. 1, figs. 1–7). bacinella is the main component in all of these microfacies; it represents more than 30 % of the total volume. the micropalaeontological associations in the whole succession include both foraminifera and algae. the following have been identifi ed: sabaudia minuta (hofker), sabaudia auruncensis chiocchini & di napoli aliata, glomospira urgoniana arnaud-vanneau, troglotella incrustans wernli & fookes, mesorbitolina texana (roemer) (pl. 2, fig. 1), mesorbitolina subconcava (leymerie) (pl. 2 fi g. 2), pseudolituonella conica luperto sinni & masse, girariarella? prismatica arnaud-vanneau. the two species of mesorbitolina (m. texana and m. subconcava) in this association have a particular signifi cance for their range does not extend downward to the gargasian (middle aptian). limestone beds of the same age, which were previously assigned to the so-called “upper pachyodont limesto ne”, are also known at varciorog where they are included in the vârciorog formation. at this location, these beds are interbedded with coarse siliciclastics. they do not exceed 15–20 m in thickness and show clear evidence of gravitational fl ow. in the subpiatră quarry, the age equivalent limestone beds are120–150 m-thick and are typical carbonate platform deposits. presumably, the carbonate succession in the subpiatră quarry area represents the upper aptian carbonate platform that provided the gravitational fl ows found in the vârciorog area where terrigenous deposits with a “fl ysch-like” character predominate. fi gu re 1: location of the study area. 1 quaternary deposits; 2 cenozoic deposits; 3 mesozoic deposits; 4 location of the studied section (subpiatră quarry). geologia croaticaioan i. bucur et al.: upper aptian calcareous algae from pădurea craiului 299 3. the calcareous algae an algal association was identifi ed at several levels in the succession. it is dominated by dasycladalean algae and it consists of: anisoporella? cretacea (dragastan), cylindroporella ivanovici (sokač),?clypeina sp., dissocladella sp., neomeris sp., russoella sp., salpingoporella sp., terquemella sp., triploporella sp., zittelina sp. and the microproblematicum coptocampylodon fontis patrulius. it includes other algal groups represented by polystrata alba pfender, parachaetetes asvapatii (pia) and rivulariacean-type cyanobacteria. anisoporella? cretacea (dragastan, 1967) (pl. 3, fig. 7) this alga was originally described from the pădurea craiului area (apuseni mountains) as pseudoepimastopora cretacea (dragastan, 1967). following its emendation to the genus pseudoepimastopora (roux, 1979) and its subsequent invalidation (granier & deloffre, 1993), the alga was assigned to two other genera: epimastoporella roux 1979 (bucur, 1992) and anisoporella botteron 1961 (bucur, 1995) (see bucur, 2000 for a detailed discussion of fi gu re 2: lower cretaceous lithostratigraphic units from the pădurea craiului mountains. 1 bauxite; 2 limestone; 3 breccia; 4 marl and shale; 5 sandstone fi gu re 3: succession and facies characteristics of the upper aptian limestones from the subpiatră quarry, with the location of algae-bearing samples geologia croatica geologia croatica 61/2–3 300 plate 1 1 bioclastic-intraclastic rudstone with large coral fragments, rudist, bivalve, gastropod and echinid fragments, and foraminifera; 8608. 2 coarse bioclastic packstone with gastropods and dasycladales; 9087. 3–4 subtidal limestones formed in a high hydrodynamic environment and subsequently subaerially exposed. stalactitic-type cement (fi g. 3, arrows) and meniscus-type cement (fi g. 4) indicating vadose diagenesis. the intergranular voids are fi lled with ostracodand small gastropod-bearing ooze, and microbialite. fig. 3, 8869; fig. 4, 8865. 5 limestone with bacinella; 8817. 6 coral bioconstructions, 8646. 7 vertical succession of facies of diff erent grain-size within peritidal deposits. the subtidal deposits formed in a high energy environment (lower part) are intercalated with subtidal deposits formed in a low-energy environment (upper part); 8793. scale bar is 1 mm for all fi gures. geologia croaticaioan i. bucur et al.: upper aptian calcareous algae from pădurea craiului 301 geologia croatica geologia croatica 61/2–3 302 plate 2 1 mesorbitolina texana (römer); 8634. 2 mesorbitolina subconcava (leymerie); 8805. 3 coptocampylodon fontis patrulius and terquemella sp.; 9011. 4 polystrata alba (pfender); 8669. 5–6 rivulariacean-type cyanobacteria. fig. 5, 9014; fig. 6, 8695 7 parachaetetes asvapatii pia; 8069. 8 terquemella sp.; 8616. scale bar is: 0.125 mm (fig. 4); 0.25 mm (figs. 1 and 2); 0.5 mm (figs. 3, 5–8) geologia croaticaioan i. bucur et al.: upper aptian calcareous algae from pădurea craiului 303 geologia croatica geologia croatica 61/2–3 304 plate 3 1–5 cylindroporella ivanovici (sokač). fig. 1, 8742; figs. 2, 3, 5, 8687; fig. 4, 8686. 6, 9 zittelina sp. fig. 6, 9087; fig. 9, 8742. 7 anisoporella? cretacea (dragastan), 8752. 8 triploporella sp.; 8740. scale bar is: 0.25 mm (fig. 4); 0.5 mm (figs. 1–3, 5–9). geologia croaticaioan i. bucur et al.: upper aptian calcareous algae from pădurea craiului 305 geologia croatica geologia croatica 61/2–3 306 synonymies and generic assignment). in fact as shown by radoičić (2005), the affi liation of the species a.? cretacea to the genus anisoporella was incorrect, anisoporella-type algae have vesiculiform laterals in a euspondyl arrangement, but with double verticils (a feature not present in a.? cretacea, which has simple euspondyl verticils). as noted by bucur et al. (2005), the morphological features of the skeleton of this alga are closer to those of the genus griphoporella as described and emended by barattolo et al. (1993). most probably, epimastopora cekici radoičić (upper hauterivian – lower barremian) and gyroporella lukicae sokač & velić (lower aptian) are ascribable to the same genus. the clarifi cation of the systematic status of anisoporella? cretacea is in progress, based on new fi nds in the jurassic and lower cretaceous deposits of the alps and the carpathians (bucur & schlagintweit, in prep.). generalised stratigraphic range: oxfordian–aptian. cylindroporella ivanovici (sokač, 1987) (pl. 3, figs. 1–5) this dasycladalean alga is the most common species in our samples. here too, the systematic assignment has undergone several changes. it was originally described as a species of the genus korkyrella sokač & velić, 1981 (sokač, 1987), which was subsequently invalidated because the type species, originally named salpingoporella texana, was considered to be invalid. the species k. ivanovici has also been considered a junior synonym of the species pseudoepimastopora pedunculata jaffrezo et al., 1980 (in the new combination cylindroporella pedunculata, see luperto sinni & masse, 1993; bodrogi et al., 1994; bucur, 2000; sotak & mišik, 1993) or it has been transferred to the genus cylindroporella (c. ivanovici) (see mancinelli, 1992; masse & isintek, 2000). sokač (2004) has revised the genus korkyrella by designating a lectotype for salpingoporella texana johnson, 1965 and has redefi ned the species korkyrella texana (a taxonomic procedure that may cause a homonymy thus leading to another invalidation of the genus korkyrella). the relationship between cylindroporella ivanovici and cylindroporella barnesii johnson (1954), has been discussed by bucur (2000), who shows that often the two species have been distinguished on the basis of “stratigraphic” criteria and may represent, in fact, a single species (see also conrad, 1982). but to confi rm this, a careful review of the type species would be required. griphoporella aurigerica conrad & peybernes (1976) may be another synonym of this species. generalised stratigraphic range: hauterivian–albian terquemella sp. (pl. 2, figs. 3pars, 8) a number of small objects in association with fossil algae have been described in the palaeoalgological literature and named either acicularia, or terquemella, both considered as the reproductive bodies (gametophores) of some dasycladales in deposits of late jurassic – early creataceous age (e.g. terquemella antiqua, pia, 1936; acicularia elongata, carozzi, 1947; acicularia jurassica, johnson, 1961; acicularia americana, konishi & epis, 1962; acicularia endoi, praturlon, 1964; acicularia intermedia, dragastan, 1967; terquemella concava, bernier, 1979). as a rule, the assignment of these objects to either one of the two organogenera was based on ambiguous or subjective criteria. most of them have been assigned to the genus acicularia. however, some have been reconsidered and assigned to the genus terquemella (e.g. t. endoi and t. antiqua, see masse, 1995; masse & arnaud-vanneau, 1999). here again a complete review is needed to clarify the taxonomy of the group. in our opinion, there is a simple and effi cient morphological criterion that may be used to differentiate the two genera: the presence of “club-shaped” longitudinal sections clearly links the gametophores’ construction to the reproductive disk of acicularia (e.g. acicularia sp., kuss & herbig, 1993). if the shape is spheroidal, ovoidal or discoid an affi liation with the genus terquemella is much more probable. this distinction is obvious when a large number of specimens are found in one sample (fossil assemblage), as is the case of the upper aptian limestone samples from pădurea craiului: they show discoid morphologies. the specimens illustrated in pl. 2, fi g. 8 represent, most probably, a new species. zittelina sp. (pl. 3, figs. 6, 9) the genus zittelina is represented in lower cretaceous deposits by only one species (zittelina hispanica masse et al., 1993) that was identifi ed fi rst in the hauterivian of spain and then recorded in the barremian-aptian deposits of the reşiţa zone (southern carpathians, romania, cf. bucur, 2001). however, the specimens identifi ed in the upper aptian of the pădurea craiului area differ from zittelina hispanica in several morphological and dimensional parameters, so they may be a separate new species. similar specimens have been illustrated by camoin (1982, pl. 1, fi gs. 2–3) under the name triploporella cf. decastroi and triploporella cf. matesina from barremian-aptian deposits in sicily. masse & arnaudvanneau (1995) have also illustrated zittelina sp. from albian deposits on a “guyot” of the northwestern pacifi c ocean. these authors consider their specimen to be a new species. it is similar to the form we described from pădurea craiului. the study of this alga is in progress based on additional material recently collected from the subpiatră quarry (pădurea craiului). we have identifi ed several other dasycladalean algae from single specimens or from a limited numbers of specimens, so these sparsely represented forms have been assigned only at the generic level (?clypeina sp., dissocladella sp., neomeris sp. – most probably a fragment of neomeris cretacea, russoella sp., salpingoporella sp., triploporella sp. – pl. 3, fig. 8). coptocampylodon fontis (patrulius, 1966) (pl. 2, fig. 3pars) this incertae sedis microfossil is very common in the barremian–aptian deposits of the tethyan domain. the clarifi cation of its taxonomy is beyond the scope of this paper. it would require a complex investigation that could clarify the status of geologia croaticaioan i. bucur et al.: upper aptian calcareous algae from pădurea craiului 307 the genus coptocampylodon and the possible affi liation of the species c. fontis to this genus or to carpathoporella dragastan 1967. the most recent papers diverge in their points of view on this subject (e.g. masse & arnaud vanne au, 1999; radoičić, 2005). remarks on the taxonomy and detailed synonymy of coptocampylodon are given in schlagintweit et al. (2002). beyond this aspect, it is notable that in the pădurea craiului area c. fontis is abundant in the aptian-albian allodapic limestones that are interbeds in the vârciorog formation. the association identifi ed in the upper aptian limestones of pădurea craiului includes two red algae: polystrata alba (pfender) and parachaetetes asvapatii pia. polystrata alba (pl. 2, fig. 4) is a peyssonneliacean alga occurring frequently in reef or para-reef deposits within the hauterivian-oligocene (?miocene) time interval. recent articles on this alga are by bassi (1997) and aguirre & braga (1999). parachaetetes asvapatii (pl. 2, fig. 7) is usually assigned to the solenoporaceans, and as a rule it has been found in upper cretaceous – palaeocene deposits, but it was identifi ed in lower cretaceous strata (granier et al., 1991), and probably, also in the upper jurassic (bucur et al., 2005). recent papers on parachaetetes asvapatii were published by stokar (2000) and aguirre & barattolo (2001); the latter’s article questioned the affi liation of this alga to the solenoporaceans. elianella elegans pfender & basse 1948 has been considered by several authors as a recent synonym of parachaetetes asvapatii (e.g. moussavian, 1989). recently, buček & köler (2005), based on material from the slovakian palaeocene, reconsidered this synonymy, favouring the preservation of two separate species. finally, concerning the rivulariacean-type cyanobacteria (pl. 2, figs. 5–6) we can state only that they are present in some shallow subtidal or intertidal facies concerning the palaeoenvironment of the upper aptian algae in the pădurea craiului area, the dasycladalean algae have been found mainly in coarse-grained facies that include fragments of corals, rudists and gastropods. only terquemella sp. is present in facies representing low energy environments. however, polystrata alba and parachaetetes asvapatii occur in reef facies, the fi rst as crusts associated with bacinella, rudists or corals; the second is more common in environments dominated by corals. 4. conclusion the upper aptian carbonate deposits cropping out in the subpiatră quarry area (aleşd, pădurea craiului mountains) most probably represent the carbonate platform from which the allodapic interbeds of the vârciorog formation were derived. we have identifi ed in these deposits an association of calcareous algae dominated by dasycladaleans, and accompanied by red algae and rivulariacean-type cyanobacteria. among the dasycladaleans, two species (terquemella sp. and zittelina sp.) are most probably new. given the dramatic decline in both numbers and species of the calcareous algae (dasycladales in particular) in the vicinity of the lower aptian/upper aptian boundary (bucur, 1999), the dasycladalean association from the upper aptian of pădurea craiului described here acquires a special palaeontological and palaeogeographical signifi cance. acknowledgment we thank dana pop and nestor sander for reviewing the english text. we also thank the two reviewers, marc a. conrad (geneve) and tonći grgasović (zagreb) for the useful comments on the paper. this research was partially supported by the cncsis grants 1330 (i. i. bucur) and ceex 13 (e. săsăran). references aguirre, j. & barattolo, f. (2001): presence of nemathecia in parachaetetes asvapatii pia 1936 (rhodophyta, gigartinales?): reproduction in “solenoporaceans” revisited. – palaeontology, 44/6, 1113–1125. agirre, j. & braga, j.c. (1999): reproductive structures in polystrata alba (pfender) denizot, 1968. – rev. paléobiol., 18/2, 619–625. barattolo, f., de castro, p. & parente, m. (1993): some remarks on griphoporella curvata (gümbel 1872) pia 1915, dasycladacean green alga from the upper triassic. – in: barattolo, f., de castro, p. & parente, m. (eds.): studies on fossil benthic algae. boll. soc. paleontol. ital., spec. vol. 1, 23–45. bassi, d. (1997): vegetative anatomy and palaeoecology of polystrata alba (pfender) denizot, 1968 (cryptonemiales, peyssonneliaceae) from upper eocene of northern italy. – rev. paléobiol., 16/2, 309–320. bernier, p. (1979): une nouvelle espèce d’algue dasycladale: terquemella concava nov. sp., dans les calcaires à “tubulures” d’age portlandien de la cluse-des-hopitaux (jura méridional). – geobios, 12/4, 597–603. bodrogi, i., bona, j. & lobitzer, h. (1994): vergleichende untersuchung der foraminiferenund kalkalgen-assoziationen der ungon-entwiklung des schrattenkalks in vorarlberg (österreich) und der nagyharsány kalkstein formation des villany-gebirges (ungarn). – in: lobitzer, h., császár, g., & daurer, a. (eds.): jubiläumschrift 20 jahre geologische zusammenarbeit österreich-ungarn, 2, 225–283. botteron, g. (1961): etude géologique de la région de mont d’or (préalpes romandes). – eclogae geol. helv., 54/1, 29–67. buček, s. & köhler, e. (2005): contribution to the recognition of the algae genus elianella. – slovak geol. mag., 11/4, 301–310. bucur, i.i. (1992): revised description of some dasyclad species from the romanian lower creataceous. – rev. paléobiol., 11/2, 447–461. bucur, i.i. (1995): algues calcaires dans les depôts du jurassique supérieur – crétacé inférieur des monts pădurea craiului. – studii şi cercetări, muzeul bustriţa năsăud, 1, 79–89. bucur, i.i. (1999): stratigraphic signifi cance of some skeletal algae (dasycladales, caulerpales) of the phanerozoic. – in: farinacci, a. & lord, a.r.m. (eds): depositional episods and bioevents. paleopelagos, spec. publ. 2, 53–104. bucur, i.i. (2000): lower cretaceous dasyclad algae from the pădurea craiului massif (northern apuseni mountains, romania). – in: bucur, i.i. & filipescu, s. (eds.): research advances in calcareous algae and microbial carbonates. acta palaeontologica romaniae, 2 (1999), 53–72. bucur, i.i. (2001): lower cretaceous algae of the reşiţa-moldova nouă zone. – in: bucur, i.i., filipescu, s. & săsăran, e. geologia croatica geologia croatica 61/2–3 308 (eds.): algae and carbonate platforms in the western part of romania. 4th regional meeting of ifaa, cluj-napoca, romania, field trip guide book. cluj university press, cluj – napoca, 137–166. bucur, i.i., hoffmann, m. & kołodziej, b (2005): upper jurassic-lowermost cretaceous benthic algae from tethys and the european platform: a case study from poland. – revista espańola de micropaleontologia, 37/1, 105–129. camoin, g. (1982): plate-formes carbonatées et récifs à rudistes du cretacé de sicilie. – thèse, université de provence, 244 p. carozzi, a. (1947): la microfl ore du purbekien du jura. note préliminaire. – c. r. soc. phys. hist. nat. genève, 64/1, 13–15. cociuba, i. (2000): upper jurassic-lower cretaceous deposits in the south-western part of pădurea craiului. formal lithostratigraphic units. – studia universitatis babeş – bolyai, geologia, xlv/2, 33–61. conrad, m.a. (1982): comments on korkyrella and other new dasycladaceae. – rev. paléobiol., 1/1, 1–5. daoud, h., bucur, i.i., săsăran, e. & cociuba, i. (2004): lower cretaceous limestones from the northern part of pădurea craiului (osoiu hill and subpiatră sections): biostratigraphy and preliminary data on microbial structures. – studia universitatis babeş – bolyai, geologia, xlix/2, 49–62. dragastan, o. (1967): alge calcaroase în jurasicul superior şi cretacicul inferior din munţii apuseni. – studii şi cercetări de geologie, geofi zică, geografi e, seria geologie, 12/2, 441–454. dragastan, o., purecel, r. & brustur, t. (1986): the upper jurassic and lover cretaceous formations from the bihor mountains – central – southern sector (northern apuseni). – analele universităţii bucureşti, 35, 57–70. dragastan, o., coman, m. & ştiucă, e. (1988): bauxite-bearing formations and facies in the pădurea craiului and bihor mountains (nortern apuseni). – revue roumaine de géologie, géophysique, géography, série géologie, 32, 67–81. granier, b. & deloffre, r. (1993): inventaire critique des algues dasycladales fossiles ii˚ partie – les algues dasycladales du jurassique et du crétacé. – rev. paléobiol., 12/1, 19–65. granier, b., berthou, p.y. & poignant, a.f. (1991): constructions bio-sédimentaires laminées lithothamnium et parachaetetes de la formation riachuelo (albien) du bassin de sergipe (nord–est du brésil). – geosciencias sao paolo, 10, 169–181. ianovici, v., borcoş, m., bleahu, m., patrulius, d., lupu, m., dimitrescu, r. & savu, h., (1976): geologia munţilor apuseni. – editura academiei rsr, bucureşti, 631 p. jaffrezo, m., poisson, a. & akbulut, a. (1980): les algues du crétacé inférieur des series de type bey daglari (taurides occidentals, turquie). – bulletin of the mineral research and exploration institute of turkey, 91 (1978), 76–88. johnson, j.h. (1954): cretaceous dasycladaceae from gillespie county, texas. – j. paleontol., 28/6, 787–790. johnson, j.h. (1961): jurassic algae from the subsurface of the gulf coast. – j. paleontol., 35/1, 147–151. johnson, j.h. (1965): three lower cretaceous algae new to the americas. – j. paleontol., 39/4, 719–720. konishi, k. & epis, r.c. (1962): some early cretaceous calcareous algae from cochise county, arizona. – micropaleontology, 8/1, 67–76. kuss, j. & herbig, h.-g. (1993): biogeography, facies and taxonomy of early tertiary green algae from egypt and morroco. – in barattolo, f. et al. (eds.): studies on fossil benthic algae, boll. soc. paleontol. ital., spec. vol. 1, 249–280. luperto sinni, e. & masse, j.-p. (1993): the early cretaceous dasycladales from the apulia region (southern italy): biostratigraphic distribution and paleobiogeographic signifi cance. – in: barattolo, f., de castro, p. & parente, m. (eds.): studies on fossil benthic algae. boll. soc. paleontol. ital., spec. vol. 1, 295–309. mancinelli, a (1992): distribuzione delle dasicladali (alge verdi) nei sedimenti del cretacico inferiore in facies di piattaforma carbonatica dell’appennino centro-meridionale (lazio e abruzzo). – studi geologici camerti, xii, 7–29. masse, p. (1995): calcareous algae and microcoprolites of the albian platform carbonates of the congo margin. – bull. centr. rech., explor.-prod. elf-aquitaine, 19/2, 301–317. masse, j.-p., arias, c. & vilas, l. (1993): zittelina hispanica et suppiluliumaella minima, dasycladales nouvelles de l’hauterivien du sud-est de l’espagne. – rev. micropal., 36/4, 293–300. masse, j.-p. & arnaud-vanneau, a. (1995): early cretaceous calcareous algae of the northwest pacifi c guyots. – in: haggerty, j.a., premoli-silva, i. rack, f. & mcnutt, m.k. (eds.): proceedings of the ocean drilling program, scientific results 144, 935–49. masse, j.-p. & arnaud-vanneau, a. (1999): early cretaceous calcareous algae of the mid-pacifi c mountains. – rev. micropal., 42/1, 57–69. masse, j.-p. & isintek, i. (2000): algues dasycladales de l’albien de la peninsule de karaburun, turqie. – rév. micropal., 43/3, 365–380. moussavian, e. (1989): ueber die systematiche stellung und die bestimungs-kriterien der solenoporaceen (rhodophyceae). – courier forschungs-institut senkenberg, 109, 51–91. patrulius, d. (1966): coptocampylodon fontis n. sp., microfossil problematic al calcarelor urgoniene din munţii perşani. – dări de se a mă ale şedinţelor, institutul de geologie, lii/1 (1964–1965), 391–394. patrulius, d., bordea, s. & avram, e. (1982): la brèche de gugu. un exemple de controle téctonique de la sédimentation sur une plate-forme carbonatée barremo-bedouliènne (pãdurea craiului, monts apuseni). – dări de seamă institutul de geologie, lxvi/4, 109–117. pfender, j. & basse, e. (1948): elianella nov. gen., elegans nov. sp., organisme constructeur de calcaires typiquement développé dans le paléocène du sw malgache. – bull. soc. géol. france, 5, 275–278. pia, j. (1936): calcareous green algae from the upper cretaceous of tripoli (north africa). – j. paleontol., 10/1, 3–13. praturlon, a. (1964): calcareous algae from jurassic-cretaceous limestone of central apennines (southern lazium – abruzzi). – geologica romana, iii, 171–202. radoičić, r. (2005): new dasycladales and microbiota from the lowermost valanginian of the mirdita zone. – annales géologiques de la péninsule balkanique, 66 (2004–2005), 27–53. roux, a. (1979): révision du genre epimastopora “pia, 1922” (dasycladaceae). – bull. centr. rech., explor. – prod. elf-aquitaine, 3/2, 803–810. schlagintweit, f., missoni, s. & gawlick, h.j. (2002): coptocampylodon? rheticus n. sp., a new problematic microfossil (“incertae sedis”) from the rhetian dachstein limestone of the northern calcareous alps (germany, austria). – geol. croat., 55/2, 107–119. sokač, b. (1987): on some controversial dasyclad genera and species and their stratigraphic position in the lower cretaceous deposits of the dinarids. – geol. vjesnik, 40, 9–38. geologia croaticaioan i. bucur et al.: upper aptian calcareous algae from pădurea craiului 309 sokač, b. (2004): on some peri-mediterranean lower cretaceous dasyclad species (calcareous algae, dasycladales) previously assigned to different genera. – geol. croat., 57/1, 15–53. sokač, b. & velić, i. (1981): korkyrella n. gen. (dasycladales) from the upper barremian and lower aptian of the island of korčula. – palaeontologia jugoslavica, 24 (1980/1), 1–12. sotak, j. & mišik, m. (1993): jurassic and lower cretaceous dasycladalean algae from the western carpathians. – in: barattolo, f., de castro, p. & parente, m. (eds.): studies on fossil benthic algae. boll. soc. paleontol. ital., special volume 1, 383–404. stokar, r. (2000): on the occurrence of parachaetetes asvapatii pia, 1936 (solenoporaceae) in the montorfano member type-section (tabiago formation, como, northern italy). – rev. paléobiol., 19/2, 427–434. manuscript received march 30, 2008 revised manuscript accepted june 16, 2008 suric.indd 155 � ab stra ct u-th and 14c dating, and x-ray diffraction of parts of 16 submerged speleothems taken from depths of 1.5−41.5 m from 7 submarine caves and pits along the eastern adriatic coast, provided insight into the sea-level fl uctuations during the last 220 ka, and to the palaeogeographic changes caused by sea-level changes. due to climate changes, palaeoenvironmental settings also varied, but not so abruptly and intensely as in the rest of europe. as the alps and dinarides acted as orographic barriers, the eastern adriatic coast was the border region between periglacial europe and the temperate mediterranean region. it was also a refuge area for plant species from the north. this study showed that appropriate temperature, humidity and vegetation cover ensured favourable conditions for karstifi cation and speleothem formation even during the last glacial maximum. keywords: palaeoenvironment, late pleistocene-holocene, u-th dating, 14c dating, sea-level change, submerged speleothems, adriatic sea, croatia late pleistocene-holocene environmental changes – records from submerged speleothems along the eastern adriatic coast (croatia) � maša surić1 and mladen juračić2 1 department of geography, university of zadar, ulica dr. franje tuđmana 24, 23000 zadar, croatia; (msuric@unizd.hr) 2 department of geology, faculty of science, university of zagreb, horvatovac 102 a, 10000 zagreb, croatia; (mjuracic@geol.pmf.hr) doi: 104154/gc.2010.13 geologia croatica 63/2 155–169 3 figs. 2 tabs. 2 pls. zagreb 2010 geologia croaticageologia croatica 1. introduction environmental conditions in the coastal zones almost completely depend on sea-land distribution. changes of this distribution during the late pleistocene-holocene period were mainly the result of the sea-level oscillations caused by global climate changes, typical for the entire quaternary period. other than on the spatial (palaeogeographic) settings, sea-land distribution had an indirect impact on climatic settings on the local and regional level, (therefore infl uencing animal and plant distribution), and on the hydrogeological settings of the coastal zones. apparently, all of these changes can be recorded in the speleothems from the submerged caves. calcite speleothems are secondary mineral deposits formed in caves by degassing of co2 from supersaturated h2o-co2-caco3 solutions that have entered the cave (dreybrodt, 2005). if these are typical subaerial features, their present positions under the sea, in submerged caves, are irrefutable evidence of former lower sea stands. as they grow, they may trap trace quantities of other minerals, fl ood debris, dust, organic matter, pollen, etc. (ford, 1997). if they contain remnants of marine organisms or any other indicator of a marine phase incorporated between the carbonate layers deposited in a continental phase, intervals of higher sea levels can be revealed. furthermore, speleothems are potentially excellent subjects for the study of long-term changes of continental mean temperature and perhaps other climatic parameters (ford & williams, 1989). geologia croatica 63/2geologia croatica 156 & lenardić-fabić, 1988; paunović & rabeder, 2000; čečuk & radić, 2005). in addition, geomorphological analyses of areas that could have experienced pleistocene glaciations, such as velebit mt., where glacial and periglacial relief (i.e., moraine material of würmian glaciers) were studied (nikler, 1973; belij, 1986; bognar et al., 1991). palaeoclimatological studies have covered much a wider region, and approximations of the lgm temperature vary geographically. according to prentice et al. (1992), the lgm in the mediterranean region was marked by temperatures 5–10 °c lower than today during the winter season, and 1–3 °c lower in summer. approximations by peyron et al. (1998), in the region south of the line defi ned by the pyrenees and alps, suggest the mean-annual temperature was 10 ± 5 °c lower than today, with the temperature of the coldest months 15 ± 5 °c lower than present. meanwhile, the shift of annual precipitation in greece and italy was estimated to be –600 mm/a. besides lower mean temperatures, miracle (1995) suggests that the seasonal temperature variations during the lgm were larger than those of today. additionally, seasonality of precipitation was also more pronounced, with relatively dry summers and rainy autumnwinter periods. total precipitation was 10–20% lower than today, but, since the decreased temperatures reduced the evaporation potential, runoff from precipitation was even larger than that of today (miracle, 1995). he also assumes that the area northwest of the adriatic basin was considerably drier than that to the southeast. the last glacial cycle is divided into fi ve marine isotope stages (mis), from mis 5 to mis 1, and includes the highest sea-level stand during the last interglacial (mis 5e), the lowest sea-level during the lgm within mis 2, and the series of oscillations of the stadials and interstadials between mis 5e and mis 2. the last period, mis 1, corresponds to the holocene, and is characterized by rapid ice decay (lambeck et al., 2002a). in tectonically stable regions, mis 5e (~128–118 ka bp) sea-level records are found consistently at an elevation of several metres above present sea level (potter & lambeck, 2004). unlike mis 5e, records of sea-levels for the mis 5a (~80 ka bp), range from –30 to +10 m (see coyne et al., 2007; references therein and fig. 18), which is explained by the effects of glacio-hydro-isostasy (potter & lambeck, 2004). within the mis 5a, two distinct sea-level highstands (double peak) have been identifi ed, at ~84 and ~77 ka bp (potter et al., 2004; potter & lambeck, 2004; radtke & schellmann, 2005). an oft-cited timing of the lgm is 21 ka bp, with sea level 121±5 m below present (fairbanks, 1989). if the lgm is considered to coincide with maximum global ice volumes, this period covers more than 10 ka with a rapid sea-level fall about 30 ka bp down to the lgm lowstand, and the onset of the global ice melting at about 19 ka bp (lambeck & chappell, 2001; lambeck et al., 2002a). the lowest sea-level stand appears to be at 26 ka bp, and it could have been as low as –135 m relative to present sea level (peltier & fairbanks, 2006). a rapid rise started around 19.6 cal ka bp and reached some 10 m within 800 years (hanebuth et al., 2009). further ice melting at during their growth, speleothems incorporate stable and radioactive isotopes of various elements that can be used to reconstruct environmental settings. variations of the ratio of stable oxygen isotopes 18o and 16o are the key for revealing changes of palaeotemperature, whilst the ratio of stable carbon isotopes 13c and 12c resolves the origin of the carbon i.e. condition of the vegetation at the surface during speleothem growth. additionally, to date the onset of the changes that are recorded in speleothems (growth cessation or recommencement, shifts in stable isotope ratios, etc.), radioactive isotopes such as 14c or the u-th series are the most useful. the eastern adriatic coast, a young ingressional karstic coast, offers a good potential for studying these phenomena as it has numerous submerged caves with speleothems from a wide range of depths. palaeoenvironmental changes recorded in speleothems primarily result in their deposition/non-deposition, depending on environmental conditions. generally, during the last glacial maximum (lgm) speleothem deposition ceased in most of europe, and began again ~15 ka bp (gascoyne, 1992; lowe & walker, 1998; mihevc, 2001). at the same time, in southern europe, speleothem deposition was uninterrupted from 20 to 15 ka bp along the tyrrhenian coast of italy (alessio et al., 1992) and during the last 60 ka in israel (soreq cave) (bar-mathews et al., 1999) as it was infl uenced by the mediterranean sea. in addition, the palaeoclimatic signal (δ18o oscillations) in this region differs markedly from northern european terrestrial records. it shifts to more negative values during the warm periods and increases during glaciations due to the prevailing infl uence of the mediterranean sea (mcgarry et al., 2004). in order to constrain the timing of sea-level oscillations by analysis of submerged speleothems, the youngest parts of the speleothems are usually dated to provide the maximum age of marine transgression, while the oldest parts provide the minimum age of continental conditions (note that cessation of speleothem growth can be caused by numerous other factors, richards & dorale, 2003). the most reliable data for the minimum age of transgression is provided by the age of the marine overgrowth that usually covers the speleothems. stalagmites with remnants of marine organisms incorporated between layers of continental origin are very peculiar, clearly distinguishing continental-marine-continental transitions (e.g. gascoyne et al., 1979; dutton et al., 2009). with the intention of reconstructing global and relative sea-level changes, submerged speleothems have been studied on tyrrhenian coast (allesio et al., 1992; bard et al., 2002; antonioli et al., 2001; 2004; 2007; dutton et al., 2009), bahamas (spalding & mathews, 1972; gascoyne et al., 1979; lundberg & ford, 1994; richards et al., 1994), bermuda (harmon et al., 1978), majorca (fornós et al., 2002; vesica et al., 2000), and croatia (malez et al., 1979; vrhovec et al., 2001; surić et al., 2005a; 2009). palaeoenvironmental studies of the eastern adriatic region have been based mostly on the spatial distribution of habitats of pleistocene fauna, (tešić, 1958; malez & božičević, 1965; malez & rabeder, 1984; malez surić and juračić: late pleistocene-holocene environmental changes – records from submerged speleothems along the eastern adriatic coast (croatia) geologia croatica 157 according to köppen’s climatic classifi cation, the northern part of the investigated area (including krk, lošinj and pag islands, and the vrulja zečica region) belongs to the contemporary cfa-type of temperate humid climate with hot summers. the middle and southern part (rogoznica and the islands of iž and brač) belong to the csa-type, which is a mediterranean climate characterized by temperate and rainy winters and hot, dry summers (šegota & filipčić, 2003). mean-annual temperatures are between 13.2 and 16.2 °c, with winter temperatures between 5.4 and 9.4 °c, and precipitation ranging from 690 to 1561 mm/a. 3. site descriptions this survey encompassed four pits, two caves, and one submarine spring, all located along the eastern adriatic coast (fig. 1). all of the surveyed features were formed within heavily fractured upper cretaceous rudist limestones with the exception of vrulja zečica, which was developed in tertiary limestone. medvjeđa spilja cave (lošinj island) is an anchialine cave with the entrance 17.5 m above mean sea level (a.m.s.l.), 55 m from the coast (fig. 2a). connection with the open sea, with distinct tidal oscillations, is established through channels and fractures in karstifi ed bedrock. according to the fi ndings of ursus speleaus remnants (malez et al., 1979), there might have originally been a horizontal entrance that is presumably now 8 m below mean sea level (b.m.s.l.), but which has been fi lled with collapsed material. the cave is well decorated with speleothems of varied age and genesis. cave in tihovac bay (pag island), with its entrance at 12 m b.m.s.l. (fig. 2b), ca 100 m off-shore, is completely within the marine environment. two massive stalagmites below the entrance indicate the existence of a major fi ssure at the locaan irregular rate lasted until 7 ka bp, when the oceans approached their present volumes (lambeck & chappell, 2001). instrumental records today show global sea-level rise to be ~1.8 ± 0.3 mm/a (church et al., 2004). in order to reconstruct palaeoenvironmental changes forced by climatic and sea-level changes on the eastern adriatic coast, this paper provides results from a variety of previous studies. these are based on the 14c dating of speleothems from three submerged caves (surić et al., 2005a), their stable isotope composition (surić et al., 2005b), and new results from extensive 14c and u-th measurements from old and new speleothem samples from seven submerged caves. in addition, thanks to colleagues, cavers, and speleodivers, a list of all presently known submerged speleological features along the croatian adriatic coast has been compiled (surić, 2006). 2. geological and environmental settings the eastern adriatic coast is an ingressive karstic coast form ed during the last late pleistocene-holocene transgression. it is characterized by the parallel extension of geological structures (folds, normal and reverse faults, overthrusts), geomorphological features, coast, channels and island chains, presenting a so-called dalmatian type coast (von richthofen, 1901). such a parallel characteristic of the dinaridic trend (nw-se) is the result of collision of the adria micro plate and eurasian plate from the alpine orogeny to the present, with maximal stress oriented sw-ne (vlahović et al., 2002; 2005; korbar, 2009). a thick carbonate succession (more than 8000 m) was deposited in several phases from the middle permian (or even upper carboniferous) to the eocene (vlahović et al., 2005). this was intensively tectonically disturbed, periodically emergent, and exposed to exogenous processes resulting in karstifi cation. karstifi cation took place down to the contemporary erosional base level (sea level), while in some places it extended below sea level (surić, 2005). according to the lgm low sea-level stand, karst features may be found down to depths of 120–130 m (lambeck et al., 2002b), but if we take into consideration the messinian salinity crisis (~6 ma bp), with sea level ~1500 m lower than today (murphy et al., 2009), evidence for karstifi cation could be expected throughout the entire adriatic region. currently the deepest speleothems found within submerged croatian caves are those from brač island at –71 m (garašić, 2006). the adriatic basin is characterized by a relatively shallow northern part with a low gradient (0.02°) down to –100 m. such morphology makes this region very sensitive to eu static sea-level changes, and consequently, it experienced considerable environmental changes throughout the quaternary period. during the lgm with sea-level 120–130 m lower than today, the entire northern part, down to the zadar-pescara line, was emergent as a wide fl uvio-lacustrine plain with a coastline located at the northern edge of the meso-adriatic depression (pirazzoli, 2000). fi gu re 1: studied localities: a – medvjeđa spilja cave (lošinj island), b – cave in tihovac bay (pag island), c – the vrulja zečica submarine spring (near starigrad), d – pit near iški mrtovnjak islet, e – u vode pit (krk island), f – zmajevo uho pit (near rogoznica), g – pit in lučice bay (brač island). geologia croatica 63/2geologia croatica 158 tion of the present-day entrance that was opened by roof collapse. two passages were explored down to 30 m b.m.s.l. vrulja zečica, near starigrad, is a periodically active submarine spring with its outlet 20 m off the coast at 9 m b.m.s.l. (fig. 2c). speleothems at 41.5 m b.m.s.l. indicate a former vadose phase. due to sea-level rise, it was subsequently transformed to a coastal spring and fi nally to a submarine one. unlike some other dispersed fresh-water outlets, vrulja zečica has a wide funnel-like shape. the pit near iški mrtovnjak islet lies entirely in the marine environment and is rich in speleothems completely covered with marine biogenic overgrowths. the entrance is 12 m off-shore at 5 m b.m.s.l., and the pit has been explored down to 25 m b.m.s.l., where it continues as a narrow passage (fig. 2d). u vode pit (krk island) is a vertical speleological feature with the entrance at 5.5 m a.m.s.l. (fig. 2e). although free circulation between the cave and the open sea is present, there is a thin brackish water lens of 0.5 m. the deepest part of the cave is within the marine environment, with marine organisms (serpulids) covering the rock and speleothem surfaces. the bottom of the pit is at 24 m b.m.s.l. the zmajevo uho pit, near rogoznica, was originally located in a shallow bay 40 m from the coast, but after the construction of an artifi cial island, its entrance is now within the pool connected to the open sea by the pipe. the opening was formed by roof collapse and is presently at 2.5 m b.m.s.l., while collapse debris covers the bottom of the pit (fig. 2f). rich marine biogenic overgrowths indicate the absence of a fresh-water infl uence. the pit in lučice bay (brač island) has two entrances formed by roof collapses at a depth of 5 m b.m.s.l. some 10 m off-shore, on a horizontal rock ledge (fig. 2g). the maximum explored depth is 40 m. marine conditions prevail in the whole pit and marine overgrowth is quite abundant. 4. sampling sampling of submerged speleothems was conducted according to the national speleological society (usa) code of conduct, suggesting that ‘the scientifi c collection should be professional, selective, and minimal’. seventeen speleo thems were collected by scuba divers from 1.5 to 41.5 m b.m.s.l. from 7 submerged caves, as follows: – u vode pit: two stalagmites from 14.5 m (k-14) and 18.8 m b.m.s.l. (k-18) (pl. 1) – medvjeđa spilja cave: ‘fallen stalactite’ from 1.5 m b.m.s.l. (l-1) and stalagmite from 10 m b.m.s.l. (l-10) (pl. 1) – cave in tihovac bay: stalactite from 23 m b.m.s.l. (p-23) (pl. 2) – vrulja zečica: stalagmite from 41.5 m b.m.s.l. (z-41) (pl. 1) – pit near iški mrtovnjak islet: three stalactites from 14 m (m-14), 19 m (m-19) and from 23 m b.m.s.l. (m-23) (pl. 1), and ‘fallen stalactite’ from 25 m b.m.s.l. (m-25) – zmajevo uho pit: two stalactites from 17 m (r-17) and 21.4 m b.m.s.l. (r-21) (pl. 2) – pit in lučice bay: stalactite from 26 m b.m.s.l. (b-26) and four stalagmites from 28 (b-28), 34 (b-34), 36 (b-36) and 38.5 m b.m.s.l. (b-38) (pl. 2). fi gu re 2: cross sections of studied caves with marked positions of sampled speleothems: a – medvjeđa spilja cave (lošinj island); b – cave in tihovac bay (pag island); c – the vrulja zečica submarine spring (near starigrad); d – pit near iški mrtovnjak islet; e – u vode pit (krk island); f – zmajevo uho pit (near rogoznica); g – pit in lučice bay (brač island) (note the diff erent scale). surić and juračić: late pleistocene-holocene environmental changes – records from submerged speleothems along the eastern adriatic coast (croatia) geologia croatica 159 plate 1: longitudinal sections of speleothems k-14, k-18, l-1, l-10, m-14, m-19, m-23 and z-41, with marked locations of subsamples for u-th and 14c dating (white squares and dotted lines) and xrd (yellow lines). white arrows (k-14 and k-18) mark hiatuses where the white substance apeared (see text). scale bar 10 cm, except for m-23, which is 5 cm. geologia croatica 63/2geologia croatica 160 we use the expression ‘fallen stalactite’ for speleothems that were collected from the cave fl oor in the growth position of stalagmites, but whose origin was primarily stalactitic (reported in surić et al., 2007) since stalagmites provide better stratigraphic resolution than stalactites and generally have less ionic mobility, stalagmites are preferred for palaeoenvironmental reconstructions and geochronological studies (richards & dorale, 2003). yet, in submarine caves, it is not possible to follow this sampling strategy thoroughly, since the bottoms of the caves, together with stalagmites, are sometimes covered with marine sediments and fallen rock debris. hence, some stalactites were also collected and analysed. after collecting speleothems from the sea, and prior to any mechanical modifi cation, biological species covering the samples were determined. afterwards, speleothems were longitudinally cut and polished to provide a view of their growth layers. samples for measurement and analysis were taken from the youngest and the oldest parts of the speleothems and along distinct hiatuses, in order to constrain the timing of cessation/recommencement or where distinct changes in morphology and mineralogy that affected speleothem deposition occurred. speleothem carbonate samples for measurement were separated by micro-drill and diamond saw: 250–450 mg for the u-th analyses, and for 14c dating ca 30 g for the measurements on a gas proportional counter (gpc) and ca 20 g for a liquid scintillation counter (lsc). the aim of mineralogical analyses on two speleothems from u vode pit (k-14 and k-18; pl.1) was to qualitatively determine the composition of the material associated with presumed hiatuses. in fresh cuts the hiatuses were highlighted by a thin red layer, but after several days of exposure to air, a white substance appeared along the discontinuities. speleothems from medvjeđa spilja cave were also mineralogically analysed in order to resolve the composition of the needle-like surface of l-1 that resembled aragonite, and the inhomogeneous material from the base of stalagmite l-10 which might have been of marine origin (pl. 1). for stable isotope measurements reported earlier (surić et al., 2005b), samples of 5–10 mg of speleothem carbonate were drilled from the successive growth layers every 5–10 mm. 5. methods the main goal of this study was the dating of certain events recorded in speleothems. therefore, three different dating tech niques were employed: u-th multi collector inductively coupled mass spectrometry (mc-icpms), and conventional β-spectrometry 14c dating using gas proportional counting (gpc) and liquid scintillation counting (lsc) methods. u-th measurements were undertaken in the bristol isotope group facilities at university of bristol, uk, using a thermofinnigan neptune mc-icpms. carbonate samples were dissolved in hno3, spiked with 229th/236u, and processed through ion exchange columns for the separation of u and th. the instrumental procedure with the mass spectrometer is reported in full in hoffmann et al. (2007) and briefl y in surić et al. (2009). the 14c dating was undertaken in the radiocarbon and tritium laboratory of ruđer bošković institute in zagreb, croatia, using a liquid scintillation counter quantulus 1220 and conventional gas proportional counter. carbonate samples were treated with dilute hcl to obtain co2 which was subsequently converted to benzene for lsc measurements (horvatinčić et al., 2004), and to methane for gpc (srdoč et al., 1971). the conventional protocol for calculation of 14c value was followed (obelić, 1989; mook & van der plicht, 1999). the 14c activity is expressed as percent of modern carbon (pmc), which relates the 14c content of a sample to the 14c content of a modern standard. the 14c age is expressed in conventional 14c years bp, adjusted to initial 14c activity (a0 = 85%), and measured δ13c (or –8‰ when not measured). calibrated ages for 14c age <22000 bp were obtained as a mean of the range obtained by oxcal v.3.10 calibration software (bronk ramsey, 2005), and for 14c age >22000 bp by the extension of the calibration curve proposed by bard et al. (2004). qualitative mineralogical composition of the samples was determined by the x-ray diffraction method (xrd). measurements were made in the faculty of natural science, university of zagreb, using a panalytical x’pert pro theta-theta diffractometer equipped with multilayer parabolic monochromator using cukα radiation. analyses of the white substance from the hiatuses were preformed by in situ measurements directly on the speleothems, then on the powder removed from the polished surface, and fi nally, samples of 2–5 mg were drilled out. moreover, speleothem carbonate was also analysed both along the discontinuity and at a distance from it. stable isotope measurements of the speleothem carbo nate were undertaken by continuous-fl ow isotope ratio mass spectrometry (cf-irms), using a finnigan gasbench and delta-s mass spectrometer located in datierungen und isotopenhydrologie sektion, institut für geowissenschaftliche gemeinschaftsaufgaben in hannover, germany. the procedure reported in surić et al. (2005b) was followed. d13c and d18o values in carbonate are expressed in ‰ deviations from the international standard pdb. the analytical error ranges from ±0.05‰ to ±0.2‰ depending on the type of sample. 6. results 6.1. marine biogenic overgrowth determination marine biogenic overgrowths can be regarded as a proxy record of prevailing environmental conditions in submerged caves, so in completely marine conditions as in the cave in tihovac bay, the pit near iški mrtovnjak, zmajevo uho pit, and the pit in lučice bay, submarine speleothems are covered with a marine overgrowth, in places more than 1 cm thick. in contrast, within the caves with fresh water input, as in the u vode pit, medvjeđa spilja cave, and vrulja zečica, marine organisms, mostly polychaeta (serpulids), have scarcely settled on the speleothems. marine overgrowths include various species of foraminifera, porifera, polychaeta, bivalvia, gastropoda and bryozoa. however, certain organisms surić and juračić: late pleistocene-holocene environmental changes – records from submerged speleothems along the eastern adriatic coast (croatia) geologia croatica 161 plate 2: longitudinal sections of speleothems b-38, b-36, b-34, b-28, b-26, r-17, r-21 and p-23, with marked locations of the subsamples for the u-th and 14c dating (bracketed with black lines) and for stable isotope analyses (white lines). scale bar 5 cm. geologia croatica 63/2geologia croatica 162 were identifi ed only to generic level and for some it was not possible to identify even the genus. identifi ed organisms belong to the biocenosis of caves and ducts in complete darkness (juračić et al., 2002) that consists exclusively of animal species adapted to complete darkness, limited seawater circulation and nutrient infl ow, and stable sea-water temperature. 6.2. mineralogical composition the mineralogical composition of samples analysed from u vode pit stalagmites was determined as follows: (i) the main components of the white material measured directly on the speleothems were halite, gypsum and calcite; (ii) the same material scratched from the surface showed the presence of halite and calcite (and possibly dolomite); (iii) in the samples drilled from the discontinuities only calcite and halite were determined; (iv) calcite was the only mineral determined far from the discontinuities (surić et al., 2009). the needle-like surface of the speleothem l-1 from medvjeđa spilja cave was determined to be calcite, with only one peak that could be ascribed to aragonite. probably metastable aragonite changed its crystal structure to stable calcite preserving the external habit of aragonite (onac, 2005). in porous and inhomogeneous material from the base of the stalagmite l-10 from the same cave, apatite and calcite were determined. this eliminates the possibility that it was of marine origin, because marine biogenic deposits consist mostly of calcite, high-magnesium calcite, aragonite and quartz (surić et al., 2005a). 6.3. u-th and 14c ages the results of u-th mc-icpms and 14c measurements are given in tables 1 and 2, respectively. locations of samples are shown in plates 1 and 2. a total of 36 u-th measurements were made on 32 speleothem subsamples and one sample of the marine biogenic overgrowth (no. 29). some samples were measured twice in order to check or confi rm the results. concentrations of 238u were in the range 29–437 ng/g (ppb), and for 232th the range was 0.08–427 ng/g, except for values of 1260 ng/g for 238u and 1217 ng/g for 232th that were recorded in the sample of marine overgrowth. an extremely high 232th concentration of 427 ng/g in speleothem carbonate was also measured at the contaminated surface part of the k-18 speleothem. such surface parts were usually avoided during sampling. initial contamination by 230th from the detritus was estimated from the 230th/232th activity ratio, so when necessary, corrections were made using the bulk earth value of th/u=3.8. three samples (ms-08, ms-12, ms-13) that had an activity ratio 230th/234u >1 gave unreliable or indeterminable ages. the u-th ages that we consider reliable cover the period from ~210 to ~20 ka bp. 6.4. stable isotope records stable isotope ratios from measured speleothems (b-28, b-34, b-36, b-38, r-17 and r-21) were given in detail in surić et al. (2005b). in the speleothem samples the d13c ranges from –10.4‰ to –6.2‰ and the d18o from –6.7‰ to –4.1‰. however, a weak correlation between d13c and d18o indicates that kinetic isotope fractionation probably occurred during calcite precipitation. according to theory and the early suggestions of hendy (1971), d18o values are directly related to the cave temperature only when calcite deposition takes place under equilibrium conditions. in the sampled speleothems deposited during the lgm, the d18o values range from –6.7‰ to –4.1‰, being very similar to the –6‰ to –3.5‰ range recorded within the holocene continental speleothems from the marine-infl uenced regions (mediterranean) (horvatinčić et al., 2003). 6.5. submerged speleological features so far, 235 submerged voids have been discovered, and partially explored, in the croatian part of the adriatic sea. among them, 163 are on or along island coasts, and 72 are along the mainland coast. this distribution matches the proportion of the lengths of island coastline (4398 km; duplančić et al., 2004) and mainland coastline (1777.3 km; statistical yearbook 2008, 2009). according to their inclination, 60% are caves and 40% are pits, although in many cases only the entrance parts were explored, and more remote channels may have a different morphology. in the continental part of the dinaric karst, 29% are caves, 60% are pits, and 2% are combined features (garašić, 1991). among the 235 features, 126 have completely marine conditions, 75 are anchialine (mostly) pits, 13 are submarine springs (vruljas), and 21 features are not determined by hydrological or environmental conditions. detailed analysis is given in surić et al. (2010), and the list of the submerged caves is available in surić (2006). speleothems, as the material for these investigations, were discovered in more than 140 submerged caves. 7. discussion 7.1. sea level changes during the last 220 ka sea-level changes are the result of vertical readjustment of the ocean-bordering landmasses at locally varying rates (hydro-isostasy) in addition to the global (eustatic) meltwater-related sea-level fl uctuations (hanebuth et al., 2009). global sea-level changes with amplitudes of several hundred metres are generally induced by plate tectonics and they occur on a time scale of millions of years, while quaternary sea-level changes are primarily induced by cyclic growth and decay of ice sheets, i.e. by climatically induced periodic exchange of mass between ice sheets and oceans (lambeck & chappell, 2001). three different approaches are generally used for the reconstruction of late pleistoceneholocene sea-level changes: (i) fi eld observations using datable sea-level markers, (ii) simulation of global sea level based on the water-equivalent ice volume on the continents, (iii) use of proxy data, such as stable oxygen isotopes, to defi ne temperature minima that correspond to sea-level minima (e.g., hanebuth et al., 2009). surić and juračić: late pleistocene-holocene environmental changes – records from submerged speleothems along the eastern adriatic coast (croatia) geologia croatica 163 eustatic sea-level changes are worldwide changes which can be reconstructed only in tectonically stable areas. in tectonically unstable regions sea-level changes take place through movement of both the land and/or sea, and they are referred to as relative sea-level changes (changes in the position of the sea relative to the land) (lowe & walker, 1998). since the eastern adriatic coast is considered tectonically active (prelogović et al., 2003) only the relative sea-level curve can be reconstructed. taking into account known eustatic sealevel changes, regional or local tectonics could be revealed. table 1: u-th ages of speleothems k-14, k-18, l-1, l-10, z–41, p-23, m-14, m-19 and m–23 and of marine overgrowth of speleothem p-23. numbers in the fi rst column correspond to the sample locations indicated in plates 1 and 2. sample no. lab. no. sample 238u (ng g–1) 232th (ng g–1) measured corrected uncorr. age (ka) corrected age (ka) (230th/232th) activity (232th/238u) activity (230th/238u) activity (234u/238u) activity (230th/238u) activity (234u/238u) activity 1 ms-43 k-14-b-50d 60.9 57.11 2.3 3.07e-01 0.7184 1.1221 0.6348 1.1584 108.7 84.7 ± 12.3 2 ms-44 k-14-b-45 67.1 7.16 18.4 3.49e-02 0.6416 1.1250 0.6320 1.1287 90.3 87.8 ± 1.3 3 ms-42 k-14-b-1d 44.9 1.39 62.2 1.01e-02 0.6296 1.1655 0.6268 1.1668 82.9 82.2 ± 1.1 4 ms-41 k-14-a-172d 69.6 15.53 8.6 7.30e-02 0.6314 1.0888 0.6102 1.0939 93.2 87.7 ± 3.7 5 ms-25 k-14-a-10 100.3 21.11 9.3 6.89e-02 0.6383 1.0825 0.6187 1.0870 95.7 90.6 ± 2.9 6 ms-08 k-18-s 212.3 426.56 1.5 6.57e-01 1.0116 1.2062 1.0228 1.4045 183.1 131.4 ± 28.4 7 ms-05 k-18-c-14l 33.4 3.25 17.2 3.19e-02 0.5506 1.3515 0.5396 1.3601 55.7 53.8 ± 2.1 8 ms-06 k-18-c-14r 38.8 4.00 17.1 3.37e-02 0.5749 1.3818 0.5639 1.3916 57.2 55.2 ± 1.4 9 ms-06 k-18-c-14r 34.4 3.46 17.6 3.29e-02 0.5806 1.4917 0.5700 1.5041 52.3 50.5 ± 5.3 10 ms-17 k-18-c-14m 34.8 3.16 18.5 2.97e-02 0.5483 1.3687 0.5381 1.3770 54.5 52.8 ± 1.1 11 ms-04 k-18-c-11 35.8 1.05 61.3 9.65e-03 0.5910 1.3911 0.5880 1.3939 58.7 58.1 ± 1.4 12 ms-03 k-18-c-2 66.5 2.03 59.3 1.00e-02 0.5933 1.2951 0.5902 1.2973 65.2 64.5 ± 1.2 13 ms-02 k-18-b-40 65.4 0.94 138.6 4.68e-03 0.6491 1.2464 0.6479 1.2472 78.1 77.7 ± 1.4 14 ms-45 k-18-b-10 48.7 1.03 96.9 6.91e-03 0.6694 1.2290 0.6677 1.2300 83.3 82.9 ± 0.6 15 ms-46 k-18-a-95l 90.2 10.69 17.6 3.88e-02 0.6833 1.1240 0.6739 1.1273 99.9 97.2 ± 1.4 16 ms-47 k-18-a-95r 80.6 10.79 15.3 4.38e-02 0.6694 1.1430 0.6582 1.1479 93.9 90.8 ± 1.5 17 ms-01 k-18-a-5 48.3 4.25 25.0 2.88e-02 0.7199 1.2167 0.7137 1.2214 94.7 93.7 ± 3.4 18 ms-23 l-1-2 205.1 36.77 12.5 5.87e-02 0.7352 1.0681 0.7231 1.0712 124.9 120.4 ± 3.2 19 ms-24 l-10-t1 254.7 6.63 37.0 8.51e-03 0.3153 1.1731 0.3110 1.1742 33.8 33.2 ± 0.5 20 ms-24 l-10-t1 253.3 6.59 37.1 8.51e-03 0.3155 1.1618 0.3112 1.1629 34.2 33.7 ± 0.6 21 ms-30 l-10-t2 259.1 4.32 35.4 5.45e-03 0.1929 1.1147 0.1896 1.1152 20.6 20.2 ± 0.5 22 ms-29 l-10-25 265.8 4.88 156.2 6.01e-03 0.9383 1.0713 0.9380 1.0716 217.3 216.8 ± 10.5 23 ms-18 m-14-t 437.1 74.85 6.3 5.60e-02 0.3531 1.0651 0.3249 1.0679 43.6 39.3 ± 2.0 24 ms-19 m-19-t1a 359.7 1.33 350.5 1.21e-03 0.4231 1.0560 0.4226 1.0561 55.4 55.3 ± 1.9 25 ms-20 m-19-t1b 388.6 5.78 74.4 4.86e-03 0.3620 1.0622 0.3597 1.0624 45.2 44.8 ± 1.0 26 ms-21 m-19-t2 222.8 0.08 4198.2 1.16e-04 0.4865 1.0418 0.4865 1.0418 68.1 68.1 ± 0.7 27 ms-22 m-23-t 231.1 7.99 77.7 1.13e-02 0.8793 1.0350 0.8782 1.0353 202.2 201.3 ± 5.5 28 ms-22 m-23-t 230.8 7.93 77.6 1.12e-02 0.8717 1.0264 0.8707 1.0266 202.9 202.0 ± 7.4 29 ms-09 p-23-mo 1259.9 1217.40 1.4 3.16e-01 0.4490 1.1510 0.2789 1.1976 53.2 28.7 ± 11.2 30 ms-10 p-23-t1 148.1 57.07 3.1 1.26e-01 0.3867 1.0987 0.3230 1.1090 46.9 37.3 ± 4.2 31 ms-11 p-23-t2 363.6 1.36 233.6 1.22e-03 0.2857 1.0812 0.2850 1.0813 33.3 33.2 ± 0.7 32 ms-31 p-23-t3 91.5 4.21 18.5 1.50e-02 0.2789 1.0609 0.2708 1.0616 33.1 31.9 ± 0.9 33 ms-12 z-41-b-40 76.3 265.54 1.5 1.14e+00 1.6677 1.1141 5.4493 1.7603 – – 34 ms-13 z-41-b-28 50.0 124.82 1.4 8.17e-01 1.1845 1.1765 1.4726 1.4521 371.2 308.1 ± 53.8 35 ms-28 z-41-b-26 28.6 15.59 2.3 1.78e-01 0.4078 1.2585 0.3169 1.2982 42.1 30.2 ± 5.2 36 ms-27 z-41-a3 60.1 48.02 1.5 2.61e-01 0.3843 1.2277 0.2351 1.2829 40.4 21.9 ± 8.2 * data 1–5 and 7–17 were presented in surić et al. (2009) geologia croatica 63/2geologia croatica 164 on the basis of the u-th and 14c ages of particular parts of sub merged speleothems, a partial sea-level curve can be reconstructed for the eastern croatian coast for the last 220 ka (fig. 3). mis 7 (245–190 ka bp) was the earliest interglacial recorded in the sampled speleothems. this stage was marked with three high sea-level stands at ~238 ka bp (mis 7e), ~216 ka bp (mis 7c) and ~195 ka bp (mis 7a) (bard et al., 2002). deposition of speleothem l-10 probably started right after the mis 7c peak, while the growth of speleothem m-23 had ceased by the subsequent mis 7a sea-level rise. mis 6 (190–130 ka bp) was the glacial event with a sea level probably as low as during the lgm (bard et al., 2002), and from that period, no speleothems have been table 2: 14c ages of speleothems l-1 and l-10 measured by a liquid scintillation counter, and of speleothems z-41, b-38, b-36, b-34, b-28, p-23 and r-21 measured by a gas proportional counter. the youngest parts are marked with a and s, while b regards the oldest parts. 14c ages are expressed as conventional 14c corrected for a0 = 85% and measured δ13c (–8‰ when not measured), and as calibrated ages. numbers in the fi rst column correspond to the sample locations on plates 1 and 2. sample no. lab. no. sample 14c activity (pmc)1 d13c (pdb ‰) 14c conventional age corrected for a0 (bp) calibrated range (cal bp)2 calibrated age (cal bp)3 37 z-3495 l-1-s 57.4 ± 0.9 –8.0 3150 ± 125 3490 – 3210 3350 38 z-3661 l-10-s 35.5 ± 0.7 –8.0 7015 ± 170 7990 – 7670 7830 39 z-3660 z-41-s 25.2± 0.8 –8.0 9760 ± 280 9700 – 8750 9225 40 z-3032 b-38-a 2.7 ± 0.5 –7.4 27 550 ± 1600 32 200 41 z-3033 b-38-b 0.0 ± 0.5 –9.5 > 37 000 42 z-3036 b-36-a 3.8 ± 0.5 –8.7 25 120 ± 1200 29 800 43 z-3037 b-36-b 1.0 ± 0.5 –9.0 > 37 000 44 z-3039 b-34-a 8.5 ± 0.6 –8.8 18 500 ± 540 22 750 – 21 250 22 000 45 z-3040 b-34-b 0.5 ± 0.5 –9.7 > 37 000 46 z-3042 b-28-a 8.9 ± 0.6 –7.2 18 150 ± 520 22 350 – 20 850 21 600 47 z-3054 p-23-a 3.6 ± 0.5 –7.5 25 480 ± 1230 30 300 48 z-3055 p-23-b 2.1 ± 0.5 –8.5 29 730 ± 2110 34 800 49 z-3057 r-21-a 5.0 ± 0.5 –6.8 22 750 ± 890 26 900 50 z-3058 r-21-b 2.4 ± 0.4 –6.2 28 505 ± 1320 33 500 1 measured 14c activity is expressed as pmc (percent of modern carbon). 2 calibrated range for the ages <22 000 bp is obtained by calibration software oxcal v.3.10 (bronk ramsey, 2005) 3 calibrated age for 14c ages <22 000 bp is obtained as a mean of the calibrated range, and for 14c ages >22 000 bp by the proposed extension of the calibration curve (bard et al., 2004). * data 40–50 were presented in surić et al. (2005a) fi gu re 3: late pleistocene-holocene relative sea-level curve (blue) based on 14c and u-th ages of 16 submerged speleothems (oran ge), correlated with the global sea-le v el curve (red), reconstructed from uth ages of coral reefs from huan (papua new guini) and bonaparte bay (australia) (adapted from lambeck et al., 2002a), and the mathematically derived curve (green) (adapted from potter & lambeck, 2004). last glacial maximum (lgm) period (light blue) according to lambeck & chappell (2001) and lambeck et al. (2002a; 2002b). surić and juračić: late pleistocene-holocene environmental changes – records from submerged speleothems along the eastern adriatic coast (croatia) geologia croatica 165 found. this could indicate glacial conditions unfavourable for speleothem deposition, as recorded throughout most of europe during the lgm. yet, we can assume that in coastal croatia, speleothem deposition was possible during the mis 6 glacial similarly to that during the lgm (surić et al., 2005a). the mis 5 (130–73 ka bp) interglacial was marked by three distinct high sea levels, with the fi rst (mis 5e at ~130 ka bp) being 6 m ± 3 m higher than at present (lambeck et al., 2004). two subsamples had ages from that period. the surface parts of the stalagmite k-18 showed a u-th age of 131.4 ka bp, but, as we know that the sea level was much higher than –18 m, the measured age was probably distorted by contamination of the surface by thorium from sea water or by leaching of uranium. an additional indicator for that contamination is the sequence of inner (younger) speleothem layers with correct stratigraphy. another doubtful value is the age of 120.4 ka bp of the inner part of l-1 speleothem found at the depth of 1.5 m, which should have been submerged during the mis 5e. investigation of the interior reveals an initial straw morphology (pl. 1), which shows that it was originally a stalactite (although it was found on the cave fl oor in growth position of a stalagmite), probably at an elevation higher then the mis 5e sea level (surić et al., 2007). speleothems from the u vode pit recorded some events from the mis 5a period; precipitation of speleothems k-18 had been more or less continuous in subaerial conditions from >93 to ~90 ka, from ~82 to ~77 ka and from ~64 to 54 ka, whereas k-14 had been growing from >90 to ~87 ka and for a brief period at 82 ka. hiatuses were marked by mineral associations (calcite, gypsum, halite) that precipitate due to the evaporation of seawater (ca-carbonates, gypsum, anhydrite, halite, k-mg chlorides, arranged from least to most soluble; seibold & berger, 1996). apparently, these hiatuses recorded the periods 90–82 ka and 77–64 ka in k-18 and 87–82 ka in k-14, which can be attributed to two mis 5a sea-level highstands known as the double peak at ~84 and ~77 ka, which has also been noticed on the uplifted island of barbados (potter & lambeck, 2004; potter et al., 2004; schellmann et al., 2004; radtke & schellmann, 2005). comparison of the present elevation of speleothems k-18 and k-14 to the ice-volume-equivalent global sea-level curve (lambeck & chappell, 2001) shows a difference of at least ~13–17 m (speleothems should have been located ~13–17 m lower than today in order to be submerged by mis 5a sea-level highstands). this difference could have resulted from long-term regional uplift at a rate of 0.15–0.25 mm/a (surić et al., 2009). during the mis 4 (73–58 ka bp) glacial, precipitation of speleothem k-18 in u vode pit continued with homogenous, dense carbonate indicating slow deposition in much dryer conditions, typical for glacial periods. growth of speleothem m-19 also continued during mis 4, and the preceding hiatus could have been of the same origin as that in k-18 caused by mis 5 transgressions. during mis 3 (58–22 ka bp), deposition of speleothem k-18 ceased, but not because of submergence, (sea level was probably ~70 m below the present one; lambeck et al., 2002a), nor because of environmental changes (it grew even during the colder mis 4). a possible reason could be a change in groundwater fl ow paths or infi lling of the feeding channel. a change of growth direction during the last growth phase is also evident (pl. 1). similarly, the cessation of m-19 and m-14 growth during mis 3 was probably not connected with submergence. mis 3 u-th ages for the speleothem l-10 are quite confusing, indicating the unsuitability of coralloids (popcorn speleothems) for dating. the majority of 14c results from the previous study (surić et al., 2005a) from the cave in tihovac bay (pag island), zmajevo uho pit, and pit in lučice bay (brač island) also fi t into mis 3 period. five of them fi t into the lgm (30–19 bp). no reliable results were obtained from mis 2 (22–11.5 ka bp). stalagmite z-41, with one part dated to 21.9 ka bp, showed signifi cant stratigraphic inversion of u-th ages, which could be expected owing to its obvious contamination with clay-rich material. the sea-level rise associated with mis 1 (11.5 ka bp – present) terminated the growth of speleothem z-41 from vrulja zečica at 9.2 ka bp, probably by a rise in groundwater level. so, after the subaerial phase, this void became a coastal spring, and subsequently a submarine one. the 14c age of the youngest part of speleothem l-10 possibly indicates cessation of growth ca. 7 ka bp, while the speleothem l-1 at –1.5 m was in vadose conditions, with needle-like deposits on its surface ca. 3350 years bp. as expected, all the ages of marine overgrowth samples also fall into the mis 1 period. although the examined speleothems cover the last 220 ka, only a partial sea-level curve for the eastern adriatic could be constructed (fig. 3) but it shows good correlation with the global sea-level curve. the few discrepancies in recorded elevations probably result from long-term regional tectonics. 7.2. palaeoenvironmental changes sea-level changes have signifi cantly changed the palaeogeographic scenery of the eastern adriatic region, but not evenly in all its parts. relatively shallow parts of the northern adriatic and southern dalmatia experienced substantial shifts in shoreline during low sea levels, whilst numerous regions with steep, even sub-vertical coasts remained almost unchanged even during sea-level fall of as much as 50 m (pikelj et al., 2009). along with sea-level changes, coastal hydrology was considerably transformed, especially in terms of submergence of coastal springs and the activation of new ones at higher elevations during sea level rise, and their drying up during sea-level fall. lowering of the absolute erosional base level resulted in river incision far below present sea level. emergence during regressional phases enabled not only deeper karstifi cation but also migration of pleistocene fauna whose remnants can be found on today’s islands that are presently too small to sustain large pleistocene animals (paunović et al., 2001). fossil remnants from the northern part of the adriatic basin (druška peć cave, mošćenička draga) consist exclusively of an alpine faunal assemblage geologia croatica 63/2geologia croatica 166 found at a relatively low elevation (335 m), suggesting substantial climatic cooling (malez et al., 1979). however, within the southeastern adriatic region (vela spila on korčula island), there are no fossil remnants of upper pleistoce ne animals adapted to colder conditions (čečuk & radić, 2005), meaning that even during the cold mis 2, climatedriven environmental changes were not so signifi cant as in the northern region. apart from the faunal migrations, emergent continental regions presented refuge areas for plant species that could not adapt to glacial conditions. thus, during the climate cooling in europe, vegetation zones did not move as a whole to the south and there was no forest belt; forests could not be maintained in southern europe, either in lowlands which were too dry, or in higher parts of mountain ranges where it was too cold. steppe vegetation dominated and forests survived in narrow zones with appropriate moist conditions (zagwijn, 1992). according to palynological research, one such zone spread along the eastern adriatic region as a refuge area for plant species from the north – coniferous forest interspersed with deciduous trees (zagwijn, 1992). aside from migrating fl oral and faunal species, conditions were probably also appropriate for early humans. abundant moisture and forest cover provided the soil and groundwater conditions ideal for dissolution and depositional karstifi cation during the lgm, and probably also during previous glacial periods. speleothem deposition and vegetation that requires damp conditions suggest that during the lgm the eastern adriatic coast was a border between a relatively temperate mediterranean zone and the periglacial part of europe to the north. along with geographic position (latitude), the adriatic sea and the alps and dinarides were the key climate modifi ers that mitigated the infl uence of climate changes, which were very severe throughout most of europe. namely, mountain ranges partly alleviated cold infl uences from the north, while the adriatic sea to the south ensured suffi cient humidity. during the lgm, the average annual temperature in the coastal area was probably 10 ± 5 °c lower than today (peyron et al., 1998), so the idea of speleothem deposition in such an environment [e.g., lgm temperature in hvar was estimated to be 7.5 °c by miracle (1995)] can be supported by recent speleothem growth in the region where temperatures are similar [e.g. in gorski kotar with annual average temperature of 7 °c (casale et al., 2004)]. the similarity between lgm and holocene d18o values (–6.7‰ to –4.1‰ and –6‰ to –3.5‰, respectively) suggests similar climatic conditions during these two periods. but, prior to carbonate deposition, the d18o signal in meteoric water is infl uenced not only by temperature but also by the transport pathway of the water vapour, distance from the coast, amount of rainfall, etc. therefore, different coastline positions during the lgm and holocene could induce d18o signal changes that would produce similar values for the two periods despite the temperature difference of 10 ± 5 °c. 8. conclusions climate changes associated with the late pleistocene-holocene period had considerable infl uence on the eastern adriatic region, in both the palaeogeographic and palaeoenvironmental sense. according to u-th and 14c ages, and minera logical composition of 16 submerged speleothems, the curve of relative sea-level changes during the last 220 ka has been partially constructed for the eastern adriatic coast, and it generally corresponds to the global sea-level curve. some sea-level stands are better resolved: sea level lower than –23 m during mis 7b (202 ka bp), the double peak during the mis 5a (84 ka and 77 ka bp) with sea level above –14 m and low sea-stand in-between at ~80 ka bp, and rapid holocene sea-level rise with sea level lower than –41.5 m (9.2 ka bp), –10 m (7.8 ka bp) and –1.5 m (3.4 ka bp). the ages of other dated samples correspond to periods with sea-level lower than present. speleothem growth cessations were not caused by climate changes – if so, simultaneous terminations should have been noticed. moreover, several speleothems grew even during the lgm. growth cessation was probably caused by infi lling of the feed er channels, changes in groundwater fl ow paths, or by submergence of the speleothems in fresh water or sea water. d18o signals could not be interpreted as a proxy for temperature due to kinetic fractionation during speleothem deposition. but speleothem growth during cold phases, preconditioned by adequate humidity and vegetation cover, suggests that the eastern adriatic area was transitional between periglacial europe and the temperate mediterranean zone, with favourable conditions not only for karstifi cation, but also for migrating plants and animals, and most probably for early humans. to obtain more precise records of palaeoenvironmental changes in the croatian coastal zone, future studies should encompass not only submerged speleothems from a wider range of depths and locations, but should also compare similar inland features and coastal sea-level markers below and above the present sea level. acknowledgement the ministry of science, education and sport of the republic of croatia funded this research (projects: 2693084-1177 "geographical features in the development of croatian coastal regions" and 1191152-1169 "recent sediments and fossil environments of the adriatic coastal zone"). part of this research was supported by the coimbra group association who enabl ed m. surić, to undertake research and u-th measurements at the school of geographical sciences, university of bristol, where the assistan ce of d. richards and d. hoffmann was most helpful and is gratefully acknowledged. we would like to thank n. horvatinčić, i. krajcar bronić and j. barešić from the radiocarbon and triti um laboratory of ruđer bošković institute for 14c measurements, d. tib ljaš for the xrd analyses, a. suckow for stable isotope measurements, and t. bakran-petricioli for the identifi cation of marine organisms. special thanks go to the speleodivers b. jalžić, v. jalžić, p. tasić, t. rađa, a. novosel, m. kuhta, m. garašić, m. kvarantan, h. hrelić, a. žulje vić, d. petricioli and s. trajbar for providing samples, photos and sketches of submerged caves. we are also grateful to the reviewers d.c. ford and a.n. palmer whose suggestions and comments greatly improved the paper. references alessio, m., allegri, l., antonioli, f., belluomini, g., ferranti, l., importa, s., manfra, l. & proposito, a. (1992): risultati preliminari relativi alla datazione di speleotemi surić and juračić: late pleistocene-holocene environmental changes – records from submerged speleothems along the eastern adriatic coast (croatia) geologia croatica 167 sommersi nelle fasce costiere del tirreno centrale [preliminary results on dating of submerged speleothems in central tyrrhenian coastal zone – in italian].– giornale di geologia, ser. 3., 54/2, 165–193. antonioli, f., silenzi, s. & frisia, s. (2001): tyrrhenian holocene paleoclimate trends from spelean serpulids.– quat. sci. rev., 20/15, 1661-1670. doi:10.1016/s0277-3791(01)00012-9 antonioli, f., bard, e., potter, e.-k., silenzi, s. & improta, s. (2004): 215-ka history of sea-level oscillations from marine and continental layers in argentarola cave speleothems (italy).– global planet. change, 43, 57–78. doi:10.1016/j.gloplacha.2004. 02.004 antonioli, f., antidei, m., lambeck, k., auriemma, r., gaddi, d., furlani, s., orrù, p., solinas, e., gaspari, a., karinja, s., kovačić, v. & surace, l. (2007): sea-level change during the holocene in sardinia and in the northeastern adriatic (central mediterranean sea) from archaeological and geomorphological data.– quat. sci. rev., 26, 2463–2486. doi:10.1016/j. quascirev.2007.06.022 bar-matthews, m., ayalon, a., kaufman, a. & wasserburg, g. (1999): the eastern mediterranean paleoclimate as a refl ection of regional events: soreq cave, israel.– earth planet. sci. lett., 166, 85–95. doi:10.1016/s0012-821x(98)00275-1 bard, e., antonioli, f. & silenzi, s. (2002): sea-level during the penultimate interglacial period based on a submerged stalagmite from argentarola cave (italy).– earth planet. sci. lett., 196, 135– 146. doi: 10.1016/s0012-821x(01)00600-8 bard, e., rostek, f. & ménot-comber, g. (2004): a better radiocarbon clock.– science, 303, 178–179. belij, s. (1986): komparativnost krškog, glacialnog i periglacialnog procesa u reliefu južnog velebita [comparison of karst, glacial and periglacial process in the relief of southern velebit – in croatian].– acta carsologica, xiv–xv, 183–196. bognar, a., faivre, s. & pavelić, j. (1991): tragovi oledbe na sjevernom velebitu [glaciation traces on the northern velebit – in croatian].– geografski glasnik, 53, 27–39. bronk ramsey, c. (2005): the oxcal program manual, v.3.10, submitted on www http://c14.arch.ox.ac.uk/embed.php?file=oxcal. html casale, a., giachino, p.m. & jalžić, b. (2004): three new species and one new genus of ultraspecialized cave dwelling leptodirinae from croatia (coleoptera, cholevidae).– nat. croat., 13/4, 301–317. church, j.a., white, n.j., coleman, r., lambeck, k. & mitrovica, j.x. (2004): estimates of the regional distribution of sea level rise over the 1950–2000 period.– j. climate, 17/13, 2609– 2625. doi: 10.1175/1520-0442(2004)017<2609:eotrdo>2.0.co;2 coyne, m.k., jones, b. & ford, d. (2007): highstands during marine isotope stage 5: evidence from the ironshore formation of grand cayman, british west indies.– quat. sci. rev., 26/3–4, 536– 559. doi:10.1016/j.quascirev.2006.06.013 čečuk, b. & radić, d. (2005): vela spila – višeslojno pretpovijesno nalazište – vela luka, otok korčula [vela spila – a stratifi ed prehistoric site – vela luka, island of korčula (croatia) – in croatian].– centar za kulturu "vela luka", vela luka, 299 p. dreybrodt, w. (2005): speleothem deposition.– in: culver, d.c. & white, w.b. (eds.): encyclopedia of caves. elsevier academic press, burlington, 431–435. duplančić leder, t., ujević, t. & čala, m. (2004): coastline length and areas of islands in the croatian part of the adriatic sea determined from the topographic maps at scale of 1:25000.– geoadria, 9/1, 5–32. dutton, a., bard, e., antonioli, f., esat, t.m., lambeck, k. & mcculloch, m.t. (2009): phasing and amplitude of climate and sea level during the penultimate interglacial.– nat. geosci., 2, 355–359. doi:10.1038/ngeo470. fairbanks, r.g. (1989): a 17000-year glacio-eustatic sea level record: infl uence of glacial melting rates on the younger dryas event and deep-ocean circulation.– nature, 342, 637–642. doi: 10.1038/342637a0 ford, d. (1997): dating and paleo-environmental studies of speleothems.– in: hill, c. & forti, p. (eds.): cave minerals of the world, 2nd ed., national speleological society, huntsville, 271– 284. ford, d.c. & williams, p. (1989): karst geomorphology and hydrology.– chapman & hall, london, 601 p. fornós, j.j., gelabert, b., ginés, a., ginés, j., tuccimei, p. & vesica, p. (2002): phreatic overgrowths on speleothems: a useful tool in structural geology in littoral karstic landscapes. the example of eastern mallorca (balearic islands).– geodinamica acta, 15, 113–125. doi:10.1016/s0985-3111(02)01083-5 garašić, m. (1991): morphological and hydrogeological classifi cation of speleological structures (caves and pits) in the croatian karst area.– geološki vjesnik, 44, 289–300. garašić, m. (2006): pronađeni i snimljeni najdublji speleothemi u moru [found and documented deepest speleothems in the sea – in croatian].– spelaeologia croatica, 7, 58. gascoyne, m. (1992): paleoclimate determination from cave calcite deposits.– quat. sci. rev., 11, 609–632. doi:10.1016/0277-3791(92)90074-i gascoyne, m., benjamin, g.j., schwarcz, h.p. & ford, d.c. (1979): sea-level lowering during the illinoian glaciation: evidence from a bahama "blue hole", science, 205, 806–808. doi: 10.1126/science.205.4408.806 hanebuth, t.j.j., stattegger, k. & bojanowski, a. (2009): termination of the last glacial maximum sea-level lowstand: the sunda-shelf data revisited.– global planet. change, 66/1–2, 76–84. doi:10.1016/j.gloplacha.2008.03.011 harmon, r.s., schwarcz, h.p. & ford, d.c. (1978): late pleistocene sea level history of bermuda.– quat. res., 9, 205–218. doi:10.1016/0033-5894(78)90068-6 hendy, c.h. (1971): the isotope chemistry of speleothems i. the calculation of the effects of different modes of formation on the isotopic composition of speleothems and their applicability as paleoclimatic indicators.– geochim. cosmochim. acta, 35, 801–824. hoffmann, d.l., prytulak, j., richards, d.a., elliott, t., coath, c.d., smart, p.l. & scholz, d. (2007): procedures for accurate u and th isotope measurements by high precision mcicpms.– int. j. mass spectrom., 264/2–3, 97–109. doi:10.1016/j. ijms.2007.03.020 horvatinčić, n., krajcar bronić, i. & obelić, b. (2003): differences in the 14c age, d13c and d18o of holocene tufa and speleothem in the dinaric karst.– palaeogeogr. palaeocl, 193, 139– 157. doi:10.1016/s0031-0182(03)00224-4 horvatinčić, n., barešić, j., bronić, i.k. & obelić, b. (2004): measurement of low 14c activities in a liquid scintillation counter in the zagreb radiocarbon laboratory.– radiocarbon, 46/1, 105–116. juračić, m., bakran-petricioli, t. & petricioli, d. (2002): cessation of karstifi cation due to the sea-level rise? case study of the y-cave, dugi otok, croatia.– in: grabovšek, f. (ed.): evolution of karst: from prekarst to cessation. založba zrc, postojna – ljubljana, 319–326. korbar, t. (2009): orogenic evolution of the external dinarides in the ne adriatic region: a model constrained by tectonostratigraphy of upper cretaceous to palaeogene carbonates.– earth sci. rev., 96/4,296–312. doi:10.1016/j.earscirev.2009.07.004 lambeck, k. & chappell, j. (2001): sea level change through the last glacial cycle.– science, 292, 679–686. doi: 10.1126/science.1059549 geologia croatica 63/2geologia croatica 168 lambeck, k., esat, t.m. & potter, e.k. (2002a): links between climate and sea level for the past three million years.– nature, 419, 199–206. doi:10.1038/nature01089 lambeck, k., yokoyama, y. & purcell, t. (2002b): into and out of the last glacial maximum: sea level change during oxygen isotope stages 3 and 2.– quat. sci. rev., 21, 343–360. doi:10.1016/ s0277-3791(01)00071-3 lambeck, k., antonioli, f., purcell, a. & silenzi, s. (2004): sea-level change along the italian coast for the past 10,000 yr.– quat. sci. rev., 23, 1567–1598. lowe, j.j. & walker, m.j.c. (1998): reconstructing quaternary environments. 2nd ed.– longman, essex, 446 p. lundberg, j. & ford, d.c. (1994): late pleistocene sea level change in the bahamas from mass spectrometric u-series dating of submerged speleothem.– quat. sci. rev., 13/1, 1–14. doi: 10.1016/ 0277-3791(94)90121-x malez, m. & božičević, s. (1965): the medvjeđa pećina (bear cave) on lošinj island, a rare case of submerged cave.– international speleological conference, brno, 1964, problems of speleological research, prague, 211–216. malez, m. & rabeder, g. (1984): neues fundmaterial von kleinsäugern aus der altpleistozänen spalten-füllung podumci 1 in norddalmatien (kroatien, jugoslawien).– beiträge zur paläontologie, 11, 439–510. malez, m. & lenardić-fabić, j. (1988): new subspecies of the southern elephant (mammuthus meridionalis adriacus n. ssp.) from the bottom of the adriatic sea (croatia, yugoslavia).– palaeontologia jugoslavica, 37, 1–36. malez, m., sliepčević, a. & srdoč, d. (1979): određivanje starosti metodom radioaktivnog ugljika kvartarnim naslagama na nekim lokalitetima u dinarskom kršu [radiocarbon dating of quaternary deposits on some localities in dinaric karst – in croatian]. rad jazu, 383, razred za prirodne znanosti, 18, 227–271. mcgarry, s., bar-matthews, m. matthews, a., vaks, a., schilman, b. & ayalon, a. (2004): constraints on hydrological and paleotemperature variations in the eastern mediterranean region in the last 140 ka given by the δd values of speleothem fl uid inclusions.– quat. sci. rev., 23, 919–934. doi:10.1016/j. quascirev.2003.06.020 mihevc, a. (2001). speleogeneza divaškega krasa [the speleogenesis of the divača karst – in slovenian].– založba zrc, ljubljana, 180 p. miracle, p.t. (1995): broad-spectrum adaptations re-examined: hunter-gatherer responses to late glacial environmental changes in the eastern adriatic.– unpubl. phd thesis, university of michigan, usa. mook, w.g., van der plicht, j. (1999): reporting 14c activities and concentrations. radiocarbon, 41, 227–239. murphy, l.n., kirk-davidoff, d.b., mahowald, n. & ottobliesner, b.l. (2009): a numerical study of the climate response to lowered mediterranean sea level during the messinian salinity crisis.– palaeogeogr. palaeocl, 279/1–2, 41–59. doi:10.1016/j. palaeo.2009.04.016 nikler, l. (1973): nov prilog poznavanju oledbe velebita [new contribution to understanding of glaciation of velebit mt. – in croatian]. – geološki vjesnik, 25, 109–112. obelić, b. (1989): the radiocarbon data base at rudjer bošković institute radiocarbon laboratory.– radiocarbon, 31, 1057–1062. onac, b. (2005): minerals.– in: culver, d.c. & white, w.b. (eds.): encyclopedia of caves, elsevier academic press, london, 371–378. paunović, m. & rabeder, g. (2000): paleoecological analysis of the pleistocene vertebrate fauna from razvodje and tatinja draga (croatia).– beiträge zur paläontologie, 25, 87–94. paunović, m., jambrešić, g., brajković, d., malez, v. & mauch lenardić, j. (2001): last glacial settlement of croatia: catalogue of fossil sites dated to the ois 2 & 3.– acta geo logica, 26/2, 27–70. peltier, w.r. & fairbanks, r.g. (2006): global glacial ice volume and last glacial maximum duration from an extended barbados sea level record.– quat. sci. rev., 25, 3322–3337. doi:10.1016/j. quascirev.2006.04.010 peyron, o., guiot, j., cheddadi, r., tarasov, p., reille, m., debeaulieu, j.l., bottema, s. & andrieu, v. (1998): climatic reconstruction in europe for 18,000 yr bp from pollen data.– quat. res., 49/2, 183–196. doi:10.1006/qres.1997.1961 pikelj, k., žigić, v. & juračić, m. (2009): origin and distribution of surface sediments in the grgur channel, adriatic sea, croatia.– geol. croat., 62 /2, 95–105. pirazzoli, p. a. (2000): sea-level changes – the last 20000 years.– wiley & sons ltd, chichester, 211 p. potter, e.k. & lambeck, k. (2004): reconciliation of sea-level observations in the west north atlantic during the last glacial cycle.– earth planet. sci. lett., 217/1–2, 171–181. doi:10.1016/ s0012-821x(03)00587-9 potter, e.k., esat, t.m., schellmann, g., radtke, u., lambeck, k. & mcculloch, m.t. (2004): suborbital-period sealevel oscillations during marine isotope substages 5a and 5c.– earth planet. sci. lett., 225, 191–204. doi:10.1016/j.epsl.2004. 05.034 prelogović, e., pribičević, b., ivković, ž., dragičević, i., buljan, r. & tomljenović, b. (2003): recent structural fabric of the dinarides and tectonically active zones important for petroleum-geological exploration in croatia.– nafta, 55/4, 155–161. prentice, i.c., guiot, j. & harison, s.p. (1992): mediterranean vegetation, lake levels and palaeoclimate at the last glacial maximum.– nature, 360, 658–660. doi:10.1038/360658a0 radtke, u. & schellmann, g. (2005): timing and magnitude of sea level change during mis 5 derived from barbados coral reef terraces: a critical literature review and new data.– j. coastal res., 21, spec. iss. 42, 52–62. richards, d.a. & dorale, j.a. (2003): uranium-series chronology and environmental applications of speleothems.– in: bourdon, b., henderson, g.m., lundstrom, c.c. & turner s.p. (eds.): uranium series geochemistry, reviews in mineralogy & geochemistry, geochemical society, mineralogical society of america, 52, 407–460. richards, d.a., smart, p.l. & edwards, r.l. (1994): maximum sea levels for the last glacial period from u-series ages of submerged speleothems.– nature, 367, 357–360. doi:10.1038/ 367357a0 schellmann, g. radtke, u., potter, e.k., esat, t.m. & mcculloch, m.t. (2004): comparison of esr and tims u/th dating of marine isotope stage (mis) 5e, 5c, and 5a coral from barbados – implications for palaeo sea-level changes in the caribbean.– quat. int., 120/1, 41–50. doi:10.1016/j.quaint.2004.01. 005 seibold, e. & berger, w.h. (1996): the sea floor – an introduction to marine geology. 3rd ed.– springer, berlin, 356 p. spalding, r.f. & mathews, t.d. (1972): stalagmites from caves in the bahamas: indicators of low sea level stand.– quat. res., 2, 470–472. doi:10.1016/0033-5894(72)90085-3 srdoč, d., sliepčević, a. & breyer, b. (1971): datiranje arheoloških nalaza biološkog porjekla metodom radioaktivnog ugljika c-14 [radiocarbon dating of archaeologic samples of biological origin – in croatian].– rad jazu, 349/2, 109–157. statistical yearbook 2008 (2009): geographical and meteorological data, republic of croatia. – central bureau of statistics, 38–59. surić and juračić: late pleistocene-holocene environmental changes – records from submerged speleothems along the eastern adriatic coast (croatia) geologia croatica 169 surić, m. (2005): submerged karst – dead or alive? examples from the eastern adriatic coast (croatia).– geoadria, 10/1, 5–19. surić, m. (2006): promjene u okolišu tijekom mlađeg pleistocena i holocena – zapisi iz morem potopljenih siga istočnog jadrana [late pleistocene – holocene palaeoenvironmental changes – records from submerged speleothems from the eastern adriatic sea (croatia) – in croatian, with an english summary].– unpubl. phd thesis, faculty of science, university of zagreb, 213 p. surić, m. (2009): reconstructing sea-level changes on the eastern adriatic sea (croatia) – an overview.– geoadria, 14/2, 181–199. surić, m., juračić, m., horvatinčić, n. & krajcar bronić, i. (2005a): late pleistocene-holocene sea-level rise and the pattern of coastal karst inundation – records from submerged speleothems along the eastern adriatic coast (croatia).– marine geology, 214, 163–175. doi:10.1016/j.margeo.2004.10.030 surić, m., horvatinčić, n., suckow, a., juračić, m. & barešić, j. (2005b): isotope records in submarine speleothems from the adriatic coast, croatia.– bulletin de la société géologique de france, 176/4, 363–373. doi: 10.2113/176.4.363 surić, m., jalžić, b. & petricioli, d. (2007): submerged speleothems – expect the unexpected. examples from the eastern adriatic coast.– acta carsologica, 36/3, 389–396. surić, m., richards, d.a., hoffmann, d.l., tibljaš, d. & juračić, m. (2009): sea level change during mis 5a based on submerged speleothems from the eastern adriatic sea (croatia).– mar. geol., 262, 62–67, doi: 10.1016/j.margeo.2009.03.005 surić, m., lončarić, r. & lončar, n. (2010): submerged caves of croatia – distribution, classifi cation and origin.– environ. earth sci. doi: 10.1007/s12665-010-0463-0 šegota, t. & filipčić, a. (2003): köppenova podjela klima i hrvatsko nazivlje [köppen’s classifi cation of climates and the problem of corresponding croatian terminology – in croatian].– geoadria, 8/1, 17–23. tešić, m. (1958): o postdiluvijalnom pozitivnom pomeranju obalske linije na istočnoj obali jadranskog mora [on postdiluvial positive shift of the eastern adriatic coastline – in croatian].– hidrografski godišnjak 1956.–1957., 153–162. vesica, p.l., tuccimei, p., turi, b., fornós, j.j., ginés, a. & ginés, j. (2000): late pleistocene paleoclimates and sea-level change in the mediterranean as inferred from stable isotope and useries studies of overgrowths on speleothems, mallorca, spain.– quat. sci. rev., 19, 865–879. doi:10.1016/s0277-3791(99)00026-8 vlahović, i., tišljar, j., velić, i. & matičec, d. (2002): the karst dinarides are composed of relics of a single mesozoic platform: facts and consequences.– geol. croat., 55/2, 171–183. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeogr. palaeocl, 220, 333–360. doi:10.1016/j.palaeo.2005.01.011 von richthofen, f. (1901): führer für forschungreisende. hannover: verlag von gebrüdek jänecke, 734 p. vrhovec, t., mihevc, a., lauritzen, s.e. & lundberg, j. (2001): o starosti potopljenih stalaktitov v jami pri otočku galiola, dalmacija, hrvatska [on the ages of submerged speleothems in the cave near galiola islet, dalmatia, croatia – in slovenian].– naše jame, 43, 31–36. zagwijn, w.h. (1992): migration of vegetation during the quaternary in europe.– in: von koenigswald w. & werdelin, l. (eds.): mammalian migration and dispersal events in the european quaternary, courier forschungsinstitut-senckenberg, frankfurt a. m., 153, 9–20. manuscript received december 15, 2009 revised manuscript accepted february 25, 2010 available online may 31, 2010 geologia croatica 63/2geologia croatica 170 seabed and surface sediment map of the kvarner region, adriatic sea, croatia (lithological map, 1:500,000) mladen jura»i∆ 1, »edomir benac 2 and ranko crmari∆ 3 1. introduction marine geological cartography has been intensively developed in the world since the 1960s. the systematic mapping of the shelf started in the uk in 1962, and the entire british shelf has already been mapped at the scale of 1:250,000. for each area/sheet at least three maps exist: seabed sediments & holocene map, quaternary geology map, and solid geology map. in the adriatic the sediments have also been intensively investigated since the 1960s (brambati & venzo, 1967; pigorini, 1968; van straaten, 1970). an example of the maps comparable to the lithological map of the kvarner region are the sedimentological textural maps of the northern and central adriatic sea, also on a scale of 1:250,000 (brambati et al., 1983, 1988a, b). the seabed characteristics of the kvarner region of the adriatic sea have been sporadically investigated since the first attempt by lorenz (1863). in this work we attempted to produce a map of the seabed and surface sediments in the kvarner region, collecting and evaluating the existing published and unpublished data on surface sediments in that region. the impetus for compiling this map was an attempt to systemise the existing data on sediments and geological structures for the regional plan of the primorsko-goranska county. the main aim of this map is to produce a synthesis of data and to visualise sediment distribution and bottom textural types, in order to infer sedimentological processes that defined the present sediment pattern. the geological and geomorphologic evolution of the area is discussed. the map may be useful for practical purposes such as fishing, better understanding of the fate of contaminants and pollutants that are introduced into the marine environment, and for any sediment scouring predictions or geotechnical investigations in this area. 2. previous investigations the first detailed sediment description in the kvarner region was published by lorenz (1863), together with a map presenting the sediment types. he indicated that most of the seabed is covered with muddy sediments, and that only to the w and sw of loπinj island do sandy sediments cover the sea bottom. alfirevi∆ g eol. croat. 52/2 131 140 2 figs. zagreb 1999 key words: sediment, recent sedimentation, holocene, quaternary, adriatic sea. 1 department of geology, faculty of science, university of zagreb, hr-10000 zagreb, zvonimirova 8, croatia. 2 faculty of civil engineering, university of rijeka, v. cara-emina 5, hr-51000 rijeka, croatia and croatian institute of civil engineering, vukovarska 10a, hr-51000 rijeka, croatia. 3 croatian hydrographic institute, zrinsko-frankopanska 161, hr21000 split, croatia. abstract a lithological map of recent marine sediments and the seabed of the kvarner region (adriatic sea, croatia) is presented on a scale of 1:500,000. the map was compiled from existing published and unpublished data. this is an area characterised by a number of islands located between the istrian peninsula and the vinodol-velebit coast. water depths in channels between the islands reach up to 125 m, compared to depths of 40-50 m in the open waters of the adjacent northern adriatic. over most of the kvarner area, muddy and sandy sediments cover the seafloor. mud (m) is found on the bottom in rijeka bay, the northern part of the kvarner, in kvarneriê, and in the vinodol and velebit channels, whereas over the rest of the kvarner region seafloor sandy mud (sm) prevails, with subordinate occurence of gravelly mud (gm). sandy sediments, i.e. muddy sands (ms) dominate in the sw part to the open adriatic, and west of rab island, in the pag and velebit channels. previous investigations indicate that the fine grained particles that are found in deeper parts of rijeka bay, kvarneriê, and vinodol channel are of recent origin, and are deposited at water depths below the wave base. sources of these particles are local permanent and temporary streams and the direct input from weathering processes, along with input by submarine springs (vrulje) near the coast. the large areas of the bottom not covered with sediments, or covered with gravelly and sandy sediments are found above the wave base, i.e. in the erosional wave zone. coarse-grained material is lithic and/or biogenic. however, due to the very rapid late glacial-holocene transgression, when sea-level rose more than a hundred metres, coarse sandy sediments are found below the recent wave base in the sw part towards the open adriatic, and west of rab island, in the pag and velebit channels. therefore the sediment distribution in the kvarner region is only partly in dynamic equilibrium with modern hydrodynamic conditions. 132 geologia croatica 52/2 (1980) indicates that in rijeka bay and the kvarneriê region sandy sediments prevail along the coasts and fine-grained sediments in the central parts. on the basis of the prevalence of zircon and garnets in the transparent fraction of heavy minerals ©krivani∆ & magdaleni∆ (1979) assigned the rijeka bay sediments to the kvarner petrographic province. the border to the padane petrographic province (which is characterised by garnets, epidote, and hornblende in the transparent fraction of heavy minerals) lies in the southern parts of the kvarner and kvarneriê. jura»i∆ & pravdi∆ (1981) indicate that the rijeka bay seabed is covered with fine grained sediments (silts and clayey silts) and that the carbonate fraction increases from 16% in the north, to 44% in the south of the bay. on the generalised sediment map of the adriatic sea (hijrm, 1985) the largest part of the rijeka bay appears covered with muddy sand, whereas in the ne part (in front of the rjeëina river mouth) sand is found. 3. study area the kvarner region (kvarner sensu lato) is part of the adriatic sea located between the istrian peninsula and the vinodol-velebit coast. two chains of larger islands, cres-loπinj and krk-rab-pag, divide the area in the rijeka bay, kvarner (sensu stricto), kvarneriê and velebit-vinodol channel. on the geographic map of the kvarner with bathymetric data presented, large and puzzling differences in water depth can be observed (fig.1). water depths in the open adriatic, west of the cres-loπinj archipelago are between 40 and 50 m, whereas in the kvarneriê (towards the coast) depths are between 70 and 90 m. in this area several seafloor elevations, isolated shoals, and submerged prolongations of island structures occur. in contrast, the bottom of rijeka bay is very flat at approximately 60 m depth. in the very narrow tihi channel, which connects rijeka bay and the vinodol channel, depths reach 60 m, whereas in the much wider northern part of the vinodol channel depths do not exceed 40 metres. in relatively narrow and elongated parts of the sea between krk and rab islands, and between rab and pag islands, depths reach more than 100 metres. the deepest point (125 m) of all the northern adriatic has recently been measured in the narrow kruπija channel between cres and plavnik islands. on land in the kvarner region lithologies include lower cretaceous limestones, cretaceous breccias, upper cretaceous intercalated limestones and dolomites, together with upper cretaceous rudist limestones. palaeogene deposits include foraminiferal limestones and clastic deposits (flysch marls, sandstones and breccias in alternation) with carbonate breccias (©iki∆ et al., 1969; ©iki∆ & pol©ak, 1973; ©iki∆ et al., 1972; ©iki∆ & pleni»ar, 1975; ©u©njar et al., 1970; grimani et al., 1973; maga©, 1968; maga©, 1973; mamuæi∆ et al., 1969, 1970; mamuæi∆ & milan, 1973; mamuæi∆, 1968, 1973; mamuæi∆ & soka», 1973). carbonates dominate, whereas flysch outcrops are restricted. quaternary deposits partly cover this bedrock substrate. in most cases, red soil (terra rossa ) that covers the carbonate substrate in the kvarner region has a polygenetic origin and was formed by the mixing of insoluble residue of carbonate rocks with weathered and eroded loess and flysch (benac & durn, 1997). elsewhere, slope deposits and weathered material cover the flysch bedrock. in accordance with the current knowledge about the formation of the adriatic and dinarides (herak, 1986; bla©kovi∆, 1990), the kvarner region had a very dynamic tectonic evolution. kvarner and istria belong to the “adriatic” geodynamic unit, which is bordered by the “dinaric” unit to the ne. regionally the “dinaric” unit overthrusts the “adriatic”. tectogenesis of the kvarner region is directly related to the subduction of the adriatic carbonate platform beneath the “dinaric” during the tertiary. the different intensity of subduction of istria and kvarner (divided by the horizontal dextral kvarner fault) under the dinaric region caused a sinusoidal twist of structures with dinaric strike (nw-se) into a meridional strike in the western kvarner (mati»ec, 1998). neotectonic movements from the lower pliocene to recent had a dominant role in the formation of the actual relief. these were vertical and horizontal movements of different direction and intensity (prelogovi∆ et al., 1981). long term vertical movements resulted in: i) the sinking of the bottom of the rijeka bay, kvarneriê and vinodol channel; ii) the tilt of the kastav plateau towards sw, and iii) substantial uplift of the uëka ridge, gorski kotar mountains, of the velebit mountain, and of some parts of the cres, krk, and rab islands. due to these tectonic movements cretaceous and palaeogene sedimentary rocks were folded and subsequently reverse faulting and overthrusting occurred. the main structures strike nw-se. the diversity of relief in the kvarner region is a consequence of contrasting lithologies, reshaping of pre-existing structures and formation of new structures, along with geomorphological processes (mihljevi∆, 1998). morphological characteristics of the relief, tectonic structures, and high seismicity indicate very active recent tectonic activity (prelogovi∆ et al., 1995, 1998). as a result of the prevalence of carbonate rocks and intensive tectogenesis, this is a region of well developed karst. karst features (e.g. dolinas, ponors, caves) are developed both on the mainland and on the islands. karstification is more pronounced above and near the sea-level and therefore in periods when the sea-level was lowered karstification in the kvarner region affected deeper levels over a more extensive area. this is why submerged karst features are widespread in the region. 133juraëiê, benac & crmariê: seabed and surface sediment map of the kvarner region... fig. 1 a) bathymetric map of the kvarner. legend: 1) water depths 0-50 m; 2) water depths 50-100 m; 3) water depths over 100 m; 4) surface sediments sampling stations. b) location map. 4. methodology and data acquisition existing data on the granulometry and mineral composition of surface sediments, together with indirect observations of the seabed by subbottom profiler (sbp) and side scan sonar (sss) were compiled in order to produce a map. results of granulometric analyses of 136 surface sediment samples of the open waters of kvarner were used (©krivani∆ & magdaleni∆, 1979; jura»i∆ & pravdi∆, 1981; benac, 1994, and unpublished data of the croatian hydrographic institute 1993-1997) (fig. 1). moreover, a large number of data on sediments of the coastal area collected primarily during geotechnical investigations were used for the production of the map, which are not presented in fig. 1. on the basis of these data we attempted to present surface sediment distribution for all of the kvarner area. sampling density is relatively high in the eastern part, but sparse in the sw. granulometric composition has been determined by wet sieving through standard sieves with diameters 4 , 0 00 -63 µm, on fritsch analysette 3, and by using particle counter coulter counter model ta ii or standard aerometric method after casagrande for particles <63 µm. classification of sediments is simplified after the internationally accepted classification for seabed sediments (folk, 1954) where the percentage of gravel (>2 mm) is compared to the sand (2-0.063 mm) and mud (silt+clay <0.063 mm) ratio. the mineral composition of part of the sediment samples has been deter134 geologia croatica 52/2 mined by standard x-ray diffraction technique (diffractometer philips pw 1050). in the coastal areas, direct observations by scuba diving were used, along with the existing data, in order to map bottom characteristics. 5. results seabed and surface sediment map on the seabed in the kvarner area four main types of substrate are found: a) rocky bottom, b) gravel and rock fragments, c) sandy sediments, and d) muddy sediments. on the map at a scale of 1:500,000 (fig. 2) the following types of bottom could be graphically distinguished: rocky bottom, gravel, pebbles, sandy gravel (g, sg); gravelly sand and sand (gs, s); gravelly muddy sand (gms); muddy sand (ms); gravelly mud (gm); sandy mud (sm); mud (m). at the bottom in the kvarner region muddy and sandy sediments prevail. mud (m) is found in the rijeka bay, the northern part of the kvarner bay, in kvarneriê, and the vinodol and velebit channels, whereas over the major part of the bottom of the kvarner area sandy mud (sm) prevails, along with some subordinate zones of gravelly mud (gm). prevalently sandy sediments i.e. muddy sand (ms) are found in the south-western part in the transition zone to the open adriatic sea and west of rab island, in the pag and southern part of the velebit channel. smaller confined zones of sandy sediments (gms) are found also near to the koromaëna bay (cres island), between the tip of the pag island, laganj rock and dolfin island, and east of ilovik island. moreover, minor patches of sand (s) and gravelly sand (gs) are found near the sources of terrigenous matter (southern part of krk island: in the baπka bay and offshore of the stara baπka settlement). larger zones of rocky bottom, and of bottom covered with gravel (sg) are found in shallow areas above the wave base (se of cres and loπinj islands, near unije island). moreover, such types of seabed are also found in deeper parts (southern part of the unije channel, w of pernat off cres island, in kruπija channel between cres and plavnik islands), where one can presume episodic very strong near bottom residual currents where both buoyancy and wind forcing may be relevant. mineral composition was investigated in more detail only in the rijeka bay samples. as presented in fig. 2 the bottom of the bay is covered with fine grained sediments (mud). mineralogical analyses have revealed that quartz and calcite dominate (>25 %), feldspars and chlorite are abundant (5 -15 %), and illite, dolomite, high-magnesian calcite, and aragonite are present (<5 %). the carbonate fraction (calcite, dolomite, highmagnesian calcite and aragonite) in sediments gradually increases from 16 % in the northern part to 44 % in the southern part of the bay (jura»i∆ & pravdi∆, 1981). around the mouth of rjeëina river, the quartz fraction in surface sandy sediments ranges between 75% and 90 % (benac, 1994). 6. discussion in accordance with the sea-level changes during geological history, the intensity and location of erosion, karstification and accumulation of sediments changed repeatedly (cowell & thom, 1997). recent land, coastal and submarine relief in the kvarner region is a consequence of tectonic movements, lithological variations, climatic changes and sea-level fluctuations during the quaternary, and also a result of erosional and accumulation processes caused by these changes. therefore the sediment distribution and bottom types encountered in the kvarner should be explained in accordance with the morphologic evolution of the region since the pliocene. it was assumed that adriatic sea-level fluctuated up to 150 m during the upper pleistocene (van straaten, 1970), causing several rises and falls. transgressive-regressive sequences in quaternary sediments of the adriatic sea indicate such sea-level oscillations (trincardi et al., 1994, 1996; tari kova»i∆, 1995; correggiari et al., 1996a). this indicates that there might have been changes from marine to continental environments in the relatively closed kvarner area. the prevalent carbonate lithology underwent much deeper karstification during periods when sealevel was lowered. due to intensive changes of relief caused by tectonic movements, the lay-out of the land and sea in the kvarner area was somewhat different in the lower part of the upper pleistocene compared to the recent. this period of the morphological evolution created a morphological frame for sedimentation during the last glacial. older sediments that were deposited in terrestrial, freshwater or marine environments were covered with younger sediments and have yet to be investigated. on the basis of parallel geomorphological and climatological analyses, a relatively accurate curve of the sea-level fluctuations since 160,000 years before present (ybp) has been produced, i.e. since the end of the riss glacial (chappell & shackleton, 1986; tooley, 1993). at the peak of the riss-würm interglacial, some 135,000 to 120,000 ybp, the global sealevel was similar to recent or <5 m higher. afterwards there was gradual decrease of the sea-level until 30,000 ybp. so during a period of 90,000 years in accordance with climatic oscillations sea-level fluctuated with 135juraëiê, benac & crmariê: seabed and surface sediment map of the kvarner region... amplitudes from 20 to 30 m, coming at least twice to the -50 or -60 m level. most researchers agree that during the würm climatic cold peak sea-level was 100 120 m below present surface (fairbridge, 1961; fairbanks, 1989), and most probably in the major part of the northern adriatic there were terrestrial conditions (d’ambrosi, 1969; van straaten, 1970; colantoni et al., 1979; ©egota, 1982; correggiari et al., 1996a). the main relief characteristics of the kvarner area during the würm must have been similar to the present, so for that period a more detailed reconstruction is posfig. 2 a) seabed and surface sediment map of the kvarner, scale 1:500,000. main 50 m and 100 m isobaths are shown. b) diagram of the relative percentage of gravel, sand and mud with textural types present (simplified after folk, 1954); abbreviations explained in the text. a ~ ... no· . 1 s t r .. _. ---\ • • • • • • -~(\ , --¢. ~ • -goi s ~ ., *.{---, . ~~---• \ k \ • • • • • • :( : · \ . • • · -b 136 geologia croatica 52/2 sible. by lowering of the sea to the -50 m level, the circulation of water through vela vrata (the strait between kvarner bay and rijeka bay) was probably interrupted. water exchange between rijeka bay and vinodol channel on one side and kvarneriê and the open adriatic on the other also became difficult. this could have caused formation of brackish or even freshwater lakes. on the other hand lowering of the erosional base induced stronger karstification of the area and enhancement of the erosional processes in non-karstic but also in karstic areas. a more humid climate during the last glacial could enhance these processes (lowe & walker, 1997). due to the lower sea-level, deposition of terrigenous material brought into the sea occurred further away from the recent coastline, in areas where terrigenous influence is negligible today. this might explain most of the sandy sediments found at depths deeper than 40 or 50 m. such terrigenous, mostly sandy sediments are very common in the outer open adriatic part in the sw part of the investigated area. most probably, rivers draining the alpine region brought this sandy material (correggiari et al., 1996b). the main source of terrigenous material that is deposited in the adriatic comes by rivers from the alps (po, adige, soëa/isonzo, tagliamento, piave, reno, brenta). today a current system of the adriatic transports and deposits that material along the italian coast (artegiani et al., 1997). during the würm, i.e. d u ring lower sea-level, istria and the cres-loπinj archipelago prevented deposition of that material in the kvarner channel zone. therefore, bottom sediments west of cres and loπinj islands are mainly sandy and belong to the padanian, and those to the east are more silty and belong to the kvarner petrographic province (©krivani∆ & magdaleni∆, 1979). however, zones of sand (s) and of gravelly sand (gs) are also found in the eastern part, around local sources of terrigenous material (flysch and loess) e.g. southern part of the krk island (baπka and stara baπka), around rab and susak islands (fig. 2). at the peak of glaciation the whole northern adriatic became land, whereas the po river and its tributaries flowed up to jabuka pit (morelli et al., 1969; trincardi et al., 1996). west of the cres-loπinj archipelago there was probably an alluvial plain, over which winds brought loess to the kvarner region (bognar & zambo, 1992). in depressions at the bottom of the recent rijeka bay and possibly vinodol channel, karst lakes probably remained and/or were formed. the bathymetrically deeper kvarneriê had contact with the open sea in middle and southern adriatic for a longer period. a rapid sea-level rise began 18,000 years ago, along with the onset of the warming of the globe. due to melting of the glacial cover sea-level rose very fast and in steps between 17,000 and 6,000 ybp, whereas afterwards the rise substantially decelerated (kidson, 1986; fairbanks, 1989; pirazzoli & pluet, 1991; bard et al., 1996). therefore drowning of the northern adriatic including the kvarner region started approximately 10,000 ybp, indicating that hydrographic and sedimentation conditions similar to the actual ones initiated in holocene. the sea drowned karst relief, and due to the fact that input of terrigenous material was relatively small, elevated rocky parts remained uncovered. however, in depressions in the paleorelief deposition of material that nevertheless came from the shore began. this fast sea-level rise until 6,000 ybp has had two effects: a deceleration of erosion/denudation due to rise of the erosional base, and change of place of deposition of fluvial material due to the shift of river mouths (benac et al., 1992). only in the last 6,000 years, due to deceleration of the sea-level rise and stillstand are the effects of the marine erosion (abrasion) more pronounced. on the kvarner coasts the effects of abrasion are not very pronounced due to low wave energy and prevalent carbonate lithology. only on the coast in less resistant material (flysch marls and quaternary sediments) are marine erosion effects pronounced (benac, 1992). carbonate rocks are primarily affected by karstification and to a lesser extent mechanical weathering. therefore the terrigenous supply in the kvarner is less pronounced. sources of terrigenous particulate material are mostly flysch outcrops in the rijeka hinterland, and on krk and rab islands. transport of material is either direct from the shores, or only sporadically via p e r m a n e n t rivers (raπa, rjeëina, dubraëina) and numerous temporary torrential flows. the direct consequence of marine erosion (abrasion) is the formation of a rocky substrate without sediment cover or with coarse grained sediments. therefore, on shores exposed to waves, the bottom, to a depth of 20 m is rocky or covered with gravel, whereas in protected coves the bottom is covered with coarse biogenous sand at 2 m depth. an area of reefs se of cres island exists where a large part of the seabed to the 10 m isobath is bedrock, and covered with gravel (sg) to a depth of 20 m. in kvarner, rocky (erosional) coasts prevail, whereas depositional (gravelly and sandy beaches) coasts are subordinate (benac et al., 1998). however, strong currents can prevent deposition of finer particle at greater depths, and this might be the reason why rocky bottoms occur in the southern part of the unije channel, west of pernat peninsula on cres island, and in kruπija channel between cres and plavnik islands (fig. 2). on carbonate shores in the kvarner region bioerosion is remarkable in the infralittoral zone. this is, like karstification, a relatively slow geomorphological process. it has been found that organisms dissolve or scrape approximately 11 kg of rock in a year along 1 m of the carbonate coast in the adriatic (schneider, 1976; torunski, 1979). part of this material is dissolved and other might be a source for recent clastic sediments. muds (>95 % of particles smaller than 0.063 mm) are characteristic cover for sea-bottoms below wave base. for example, in the sheltered bakar bay floccu137juraëiê, benac & crmariê: seabed and surface sediment map of the kvarner region... lated cohesive mud is found on the bottom at 20 m depth, whereas on shores exposed to waves in istria near brseë or along cres island muddy sediments are found only at depths greater than 50 metres. it is suggested that fine grained muddy material found in the deeper parts (rijeka bay, vinodol channel, northern part of the velebit channel, kvarneriê) is of recent origin and is deposited according to recent hydrographic conditions, i.e. beneath the wave base. sources of this fine grained material are permanent and temporal flows, direct input of weathered material, and probably submarine springs (vrulje) along the coast. the mineral composition of sediments is known in more detail only for rijeka bay. a terrigenous influence in coarse grained sediment is most prominent at the rjeëina river mouth where quartz and siliciclastics transported from the flysch hinterland occur. analogously, sediments at the dubraëina river mouth may have similar composition. according to the prevalence of quartz and siliciclastics in the beach sands of rab island (crnjakovi∆ et al., 1998), one can presume similar composition and terrigenous origin of coarse grained sediments offshore the rab island. red soil (terra rossa ) ubiquitous on the land in kvarner region is polygenetic, and its distribution is a consequence of erosion and accumulation (benac & durn, 1997). erosion of these soil deposits may also be a source of particles for bottom sediments. part of the sandy particles in kvarner bottom sediments are also biogenic (calcite, mg-calcite and aragonite shells, skelets and their fragments). biological processes of sediment mixing (bioturbation) are most probably responsible for the formation of mixed (fine and coarse grained) sediments found prevalently at the bottom such as muddy sand (ms) and sandy mud (sm). in case of sediments found in the kvarner region bioturbation most probably causes mixing of the upper layer of fine grained recent sediment with deeper laying residual terrigenous sand. the thickness of marine holocene sediments in the kvarner region is only partially known. marine seismic techniques (deep seismic profiles) and subbottom profiles (shallow profiles) were systemised only for the rijeka bay (benac, 1996; jura»i∆ et al., 1998). they indicate that the base to the first prominent reflector (presumed base of unconsolidated or semiconsolidated holocene sediment) in open waters of the rijeka bay varies from 2 to 10 metres. from the presumed initiation of holocene marine sedimentation and the measured thickness, the calculated average sedimentation rate of holocene mud is between 0.2 and 1.7 mm/year (jura»i∆ et al., 1998). however, near the rjeëina and dubraëina river mouths, where terrigenous input dominates, the depth of holocene sediments is a few tens of metres (benac et al., 1992). holocene sediments more than ten metres thick were also found by exploratory drilling in the vicinity of mouths of ephemeral creeks (torrents). 7. conclusions sediment distribution on the sea floor of the kvarner region is a consequence of a few morphogenetic steps correlated with sea-level changes during the pleistocene. during younger morphogenetic steps traces of the former sea-level fluctuations were destroyed and masked. sea-level and climatic oscillations during the würm had a paramount influence on sedimentation in the kvarner. due to the much lowered sea-level in some periods of the würm glacial, connections between rijeka bay, kvarneriê, and vinodol channel and the open adriatic were reduced or even interrupted. during conditions of lower sea-level the elevations of the cresloπinj archipelago were a morphologic barrier that divided the open adriatic sedimentation zone from the relatively isolated kvarner basin. therefore, bottom sediments west of cres and loπinj are prevalently sandy and belong to the padanian watershed, and those to the east, prevalently muddy, belong to the kvarner petrographic province. when sea-level was lowered, coarse-grained terrigenous sediments were deposited in deeper parts of the kvarner, where recent hydrographic conditions do not facilitate such deposition. however, restricted zones of sand (s) and gravelly sands (gs) occur near the local sources of coarse terrigenous material, e.g. south of the krk island, near rab island or in front of the rjeëina and dubraëina river mouths. some of the coarse-grained particles found in sediments are biogenic. due to the rapid late würm holocene transgression, when sea-level rose more than 100 m, parts of the prevalently karstic land were drowned and recent sedimentation environments formed. the sources of the fine grained material that cover the deepest basins are a few permanent and ephemeral flows, direct coastal weathering, and presumably underwater springs (vrulje) located along the coast. these deposits are in accordance with recent hydrographic conditions. on the other hand, coarse-grained sandy sediments found in open waters sw of cres and loπinj islands and between rab and pag islands, along with the coarse-grained terrigenous fraction of mixed muddy/sandy sediments are found below the wave base. they were presumably deposited during the würm or during the holocene transgression in different hydrographic conditions, and are not concordant with recent hydrographic conditions. these sediments are found on the seafloor where there is not enough terrigenous material to cover them. this map has been produced on the basis of existing data, and indicates the main sediment pattern of the kvarner region. older quaternary sediments have not yet been investigated thoroughly, and require further research. 138 geologia croatica 52/2 acknowledgement this research has been partly supported by ministry of science and technology of the republic of croatia (project 119301). the authors wish to thank the referees prof. antonio brambati and especially to dr. fabio trincardi for their constructive criticism that substantially improved the manuscript. we also thank to m. kladni»ki for careful drawings. 8. references alfirevi∆, s. (1980): sedimentoloπko kartiranje bentoskih biocenoza u kanalima sjeveroistoënog jadrana.geoloπki vjesnik, 32, 15-32. artegiani, a., bregant, d., paschini, e., pinardi, n., raicich, f. & russo, a. (1997): the adriatic sea general circulation. part ii: baroclinic circulation structure.journal of physical oceanography, 27, 1515-1532. bard, e., hamelin, b., arnold, l.m., cabioch, g., faure, g. & rougerie, f. (1996): deglacial sea-level record from tahiti corals and the timing of global meltwater discharge.nature, 382, 241-244. benac, ». (1992): recentni geomorfoloπki procesi i oblici u podruëju rijeëkog zaljeva.geografski glasnik, 54, 1-18. benac, ». (1994): inæenjerskogeoloπke osobitosti obalnog pojasa i podmorja rijeëkog zaljeva.unpubl. phd thesis, university of zagreb, 152 p. benac, ». (1996): morfoloπka evolucija rijeëkog zaljeva: utjecaj klimatskih i glacioeustatiëkih promjena.acta geographica croatica, 31, 69-84. benac, »., arbanas, æ. & jardas, b. (1992): morphogenesis and evolution of the river mouths in the kvarner area.proceedings of international symposium: geomorphology and sea, mali loπinj 1992, 37-45, zagreb. benac, ». & durn, g. (1997): terra rosa in the kvarner area geomorphological conditions of formation.acta geographica croatica, 32, 7-19. benac, »., jardas, b., arbanas, æ. & ili∆, s. (1998): zaπtita æala na podruëju kvarnera.proceedings of 14th biennal international congres, 2, opatija, 647-656. bla©kovi∆, i. (1990): nova globalna tektonika i primjena koncepcije u podruëju jadranskog mora.pomorski zbornik, 28, 555-581. bognar, a. & zambo, l. (1992): some new data of the loess genesis on susak island.proceedings of the international symposium geomorphology and sea, mali loπinj 1992, zagreb, 65-72. brambati, a. & venzo, g.a. (1967): recent sedimentation in the northern adriatic sea between venice and trieste.st. trent. sc. nat., sez. a, 44, 202-274. brambati, a., ciabatti, m., fanzutti, g.p., marabini, f. & marocco, r. (1983): a new sedimentological textural map of the northern and central adriatic sea.bolletino di oceanologia teorica ed applicata, 1/4, 267-271. brambati, a., ciabatti, m., fanzutti, g.p., marabini, f. & marocco, r. (1988a): carta sedimentologica dell’adriatico settentrionale, 1: 250000.consiglio nazionale delle ricerche. brambati, a., ciabatti, m., fanzutti, g.p., marabini, f., & marocco, r. (1988b): carta sedimentologica dell’adriatico centrale, 1: 250000.consiglio nazionale delle ricerche. chapell, j. & shackleton, n.j. (1986): oxygen isotopes and sea level.nature, 324, 137-140. colantoni, p., galignani, p. & lenaz, r. (1979): late pleistocene and holocene evolution of the north adriatic continental shelf (italy).marine geology, 33, m41-m45. correggiari, a., roveri, m. & trincardi, f. (1996a): late pleistocene and holocene evolution of the north adriatic sea.il quaternario italian journal of quaternary science, 9/2, 697-704. correggiari, a., field, m.e. & trincardi, f. (1996b): late quaternary transgressive large dunes on the sediment-starved adriatic shelf.in: de batist, m. & jacobs, p. (eds.): geology of sili ciclastic shelf seas. geological society special publication, 117, 155-169. crnjakovi∆, m., babi∆, lj. & zupani», j. (1998): odræivost plaæa hrvatske obale jadrana: sediment kao glavni faktor.in: arko-pijevac, m., kova»i∆, m. & crnkovi∆, d. (eds.): prirodoslovna istraæivanja rijeëkog podruëja. prirodoslovna biblioteka, 1, prirodoslovni muzej rijeka, 333-338. d’ambrosi, c. (1969): l’adriatico nel quaternario.atti del museo civico di storia naturale, 26/5, 129175. fairbanks, g.r. (1989): a 17,000-year glacioeustatic sea level record: influence of glacial melting rates on the younger dryas event and deep ocean circulation.nature, 324, 637-642. fairbridge, r.w. (1961): eustatic changes in sea level.phys. chem. earth, 4, 99-185. folk, r.l. (1954): the distinction between grain size and mineral composition in sedimentary-rock nomenclature.journal of geology, 62, 344-359. grimani, i., ©u©njar, m., bukovac, j., milan, a., nikler, l., crnolatac, i., ©iki∆, d. 139juraëiê, benac & crmariê: seabed and surface sediment map of the kvarner region... & bla©kovi∆, i. (1973): osnovna geoloπka karta sfrj 1:100.000. tumaë za list crikvenica l33-102 (basic geological map 1:100.000, geology of crikvenica sheet).inst. za geol. istraæ. zagreb (1963), sav. geol. zavod beograd, 47 p. herak, m. (1986): a new concept of geotectonics of the dinarides.acta geologica, 16/1, 1-42, zagreb. hijrm (1985): jadransko more, generalna karta sedimenata dna 1:1.000.000.hidrografski institut jugoslavenske ratne mornarice, split. jura»i∆, m. & pravdi∆, v. (1981): geochemical and physico-chemical studies on sediments of rijeka bay: the properties of sediments as depositories of pollutants.thalassia jugoslavica, 17/3-4, 339349. jura»i∆, m., crmari∆, r. & benac, ». (1998): holocenski sedimenti i sedimentacija u rijeëkom zaljevu.in: arko-pijevac, m., kova»i∆, m. & crnkovi∆, d. (eds.): prirodoslovna istraæivanja rijeëkog podruëja. prirodoslovna biblioteka, 1, prirodoslovni muzej rijeka, 339-344. kidson, c. (1986): sea-level changes in the holocene.in: van de plassche, o. (ed.): sea-level research: a manual for the collection and evaluation of data. geo books, norwich, 27-66. lorenz, j.r. (1863): physicalische verhältnisse und vertheilung der organismen im quarnerischen golfe.kais. kön. hofund staatsdruck., wien, 379 p. lowe, j.j. & walker, m.j.c. (1997): reconstructing quaternary environments.longman, london, 446 p. maga©, n. (1968): osnovna geoloπka karta sfrj 1:100.000. list cres l33-113 (basic geological map 1:100.000, cres sheet).inst. za geol. istraæ. zagreb (1965), sav. geol. zavod beograd. maga©, n. (1973): osnovna geoloπka karta sfrj 1:100.000. tumaë za list cres l33-113 (basic geological map 1:100.000, geology of cres sheet).inst. za geol. istraæ. zagreb (1965), sav. geol. zavod beograd, 42 p. mamuæi∆, p. (1968): osnovna geoloπka karta sfrj 1:100.000. list loπinj l33-125 (basic geological map 1:100.000, loπinj sheet).inst. za geol. istraæ. zagreb (1965), sav. geol. zavod beograd. mamuæi∆, p. (1973): osnovna geoloπka karta sfrj 1:100.000, tumaë za list loπinj l33-125 (basic geological map 1:100.000, geology of loπinj sheet).inst. za geol. istraæ. zagreb (1965), sav. geol. zavod beograd, 34 p. mamuæi∆, p. & milan, a. (1973): osnovna geoloπka karta 1:100.000. tumaë za list rab l33-114 (basic geological map 1:100.000, geology of rab sheet).inst. za geol. istraæ. zagreb (1966), sav. geol. zavod beograd, 39 p. mamuæi∆, p. & soka», b. (1973): osnovna geoloπka karta 1:100.000. tumaë za list silba l33-138 i molat l33-126 (basic geological map 1:100.000, geology of silba and molat sheets).inst. za geol. istraæ. zagreb (1967), sav. geol. zav. beograd, 45 p. mamuæi∆, p., milan, a., korolija, b., borovi∆, i. & majcen, æ. (1969): osnovna geoloπka karta 1:100.000. list rab l33-114 (basic geological map 1:100.000, rab sheet).inst. za geol. istraæ. zagreb (1965), sav. geol. zavod beograd. mamuæi∆, p., soka», b. & veli∆, i. (1970): osnovna geoloπka karta 1:100.000. list silba l33-138 (basic geological map 1:100.000, silba sheet).inst. za geol. istraæ. zagreb (1969), sav. geol. zavod beograd. mati»ec, d. (1998): analiza strukturnog sklopa uëke.unpublished phd. thesis, university of zagreb, 135 p. mihljevi∆, d. (1998): reljef strukturnog podrijetla i strukturno-geomorfoloπke regije istre i kvarnera.in: arko-pijevac, m., kova»i∆, m. & crnkovi∆, d. (eds.): prirodoslovna istraæivanja rijeëkog podruëja. prirodoslovna biblioteka, 1, prirodoslovni muzej rijeka, 277-302. morelli, c., carrozzo, m.t., ceccherini, p., finetti, i., gantar, c., pisani, m. & schmidt, p. (1969): regional geophysical study of the adriatic sea.bollettino di geophisica teorica ed applicata, 11 (41-42), 3-33. pigorini, b. (1968): sources and dispersion of recent sediments of the adriatic sea.marine geology, 6/3, 187-229. pirazzoli, p.a. & pluet, j. (1991): holocene changes in sea level as climate proxy data in europe.in: frenzel, b. (ed.): evaluation of climate proxy data in relation to the european holocen. paleoklimaforschung, 6, mainz-strasbourg-new york, 205-225. prelogovi∆, e., bla©kovi∆, i., cvijanovi∆, d., skoko, d. & aljinovi∆, b. (1981): seizmotektonske znaëajke vinodolskog podruëja.geoloπki vjesnik, 33, 75-93. prelogovi∆, e., kuk, v., jami»i∆, d., aljinovi∆, b. & mari∆, k. (1995): seizmotektonska aktivnost kvarnerskog podruëja.1. hrvatski geoloπki kongres, opatija, zbornik radova, 2, 487-490, zagreb. prelogovi∆, e., kuk, v. & buljan, r. (1998): the structural fabric and seizmotectonic activity of northern velebit: some new observations.rudarsko-geoloπko-naftni zbornik, 10, 39-42. schneider, j. (1976): biological and inorganic factor in the destruction of limestone coasts.contribution to sedimentology, 6, 1-112. 140 geologia croatica 52/2 ©egota, t. (1982): razina mora i vertikalno gibanje dna jadranskog mora od ris-virmskog interglacijala do danas.geol. vjesnik, 35, 93-109. ©iki∆, d. & pleni»ar, m. (1975): osnovna geoloπka karta 1:100.000., tumaë za list ilirska bistrica l33-89 (basic geological map 1:100.000, geology of ilirska bistrica sheet).inst. za geol. istraæ. zagreb and geol. zav. ljubljana (1967), sav. geol. zav. beograd, 51 p. ©iki∆, d. & pol©ak. a. (1973): osnovna geoloπka karta 1:100.000. tumaë za list labin l33-101 (basic geological map 1:100.000, geology of labin sheet).inst. za geol. istraæ. zagreb (1965), sav. geol. zavod beograd, 55 p. ©iki∆, d., pleni»ar, m. & ©parica, m. (1972): osnovna geoloπka karta 1:100.000. list ilirska bistrica l33-89 (basic geological map 1:100.000, ilirska bistrica sheet).inst. za geol. istraæ. zagreb and geol. zavod ljubljana (1967), sav. geol. zavod beograd. ©iki∆, d., pol©ak, a. & maga©, n. (1969): osnovna geoloπka karta 1:100.000. list labin l33-101 (basic geological map 1:100.000, labin sheet).inst. za geol. istraæ. zagreb (1967), sav. geol. zavod beograd. ©krivani∆, a. & magdaleni∆, z. (1979): cruises of the research vessel “vila velebita” in the kvarner region of the adriatic sea. ix. quaternary sea bottom sediments.thalassia jugoslavica, 15, 149-166. ©u©njar, m., bukovac, j., nikler, l., crnolatac, i., milan, a., ©iki∆, d., grimani, i., vuli∆, æ. & bla©kovi∆, i. (1970): osnovna geoloπka karta 1:100.000. list crikvenica l33-102 (basic geological map 1:100.000, crikvenica sheet).inst. za geol. istraæ. zagreb (1969), sav. geol. zav. beograd. tari kova»i∆, v. (1995): razvoj pliocenskih i pleistocenskih naslaga sjevernog i srednjeg jadrana karotaæni markeri i korelacija.1. hrvatski geoloπki kongres, opatija, zbornik radova, 2, 609-612, zagreb. tooley, m.j. (1993): long term changes in eustatic sea level.in: warrick, r.a., barrow, e.m. & wigley, t.m. (eds.): climate and sea level change: observations, projections and implications. cambridge university press, 81-110. torunski, h. (1979): biological erosion and significance for the morphogenesis of limestone coasts and for nearshore sedimentation (northern adriatic).senckenbergiana maritima, 11, 193-265. trincardi, f., correggiari, a. & roveri, m. (1994): late quaternary transgressive erosion and deposition in a modern epicontinental shelf: the adriatic semienclosed basin.geo-marine letters, 14, 41-51. trincardi, f., cattaneo, a., asioli, a., correggiari, a. & langone, l. (1996): stratigraphy of the late-quaternary deposits in the central adriatic basin and the record of short-term climatic events.in: guillizoni, p. & oldfield, f. (eds.): paleoenvironmental analysis of italian crater lake and adriatic sediments (paliclas). memorie dell’istituto italiano di idrobiologia, 55, 39-70. van straaten, l.m.j.u. (1970): holocene and late pleistocene sedimentation in the adriatic sea.geol. rundsch., 60, 106-131. manuscript received april 29, 1999. revised manuscript accepted november 12, 1999. geo.cro.2-3-61-kb.pdf 135 � baba senowbari-daryan1, hossein torabi2 and koorosh rashidi3 ab stra ct two reef-building red algae of the family solenoporaceae – solenopora rectangulata n. sp. and parachaetetes dizluensis n. sp. – are described from a ?norian-rhaetian section of the nayband formation exposed south of the town of bagherabad, northeast of esfahan, central iran. these algae build reef structures or patches up to 17 m thick, either on their own or in association with other reef-building organisms including sponges, corals, etc. such solenoporacean reef structures have not been described before, either from iran or elsewhere in the world. morphologically, both algae are easily distinguished by the different sizes of their thalli and particularly by their branching pattern. keywor ds: algae, solenopora, parachaetetes, triassic, reef, iran 1 geozentrum nordbayern, university of erlagnen-nürnberg, loewenichstr. 28, d-91064 erlangen, germany; (basendar@pal.uni-erlangen.de) 2 department of erath sciences, university of esfahan, esfahan, iran 3 university of payame-e noor, ardakan, iran new solenoporaceans from upper triassic (?norian-rhaetian) reef limestones in central iran geologia croatica 61/2–3 135–157 7 figs. 2 tabs. 8 pls. zagreb 2008 geologia croaticageologia croatica � 1. introduction upper triassic (norian-rhaetian) deposits of the nayband formation are distributed over a large area in central and eastern iran (seyed-emami, 1971, 2003). the type locality of the nayband formation crops out at the southern area of the kuh-e nayband (nayband mount), approximately 220 km south of the town of tabas in northeastern iran where it reaches a thickness of about 3000 m (fürsich et al., 2005). reefs occur interbedded within the nayband formation and are usually biostromes, but small bioherms also occur (generally less than 50 m thick and less than 100 m laterally). the reefs are mainly sponge-coral or coral-sponge dominated. other organisms are of minor importance (senowbaridaryan, 1996, 2005a, 2005b). various groups of calcareous algae occur within the carbonate facies of the nayband formation. solenoporaceans are usually found in reef facies while dasycladales occur main ly in bedded carbonates (senowbari-daryan & hameda ni, 1999, 2000). until now, in iran and elsewhere in the world, solenoporaceans have only been found as minor components of reefs or reef-like structures and never as the main reef -building organism. in an outcrop section through the nayband formation northeast of esfahan (figs. 1–2), as well as sponges and corals, two erect and multi-branched species of solenoporacean red algae are the main reef builders to have acted as baffl ers to current-borne sediment grains. the two species can be distinguished in the fi eld by the different size of their thalli (pl. 2, figs. a–b). the fi rst species (pl. 2, fig. b: small arrows) is described as solenopora rectangulata n. sp. and has smaller and multi-branched thalli, the branching angle being up to 90o and giving the appearance of a fi r-tree (pl. 3, figs. a–b). the second species (pl. 2, fig. b: large arrows) has large and fi ngerlike multi-branched thalli and is described as parachaetetes dizluensis n. sp. holoand paratypes of both species are deposited in the forschungsinstitut senckenberg, frankfurt am main. (in ven tary – nr. mb. 21123-21130; one rock piece and 7 thin sec tions). 2. locality and section the outcrop of the nayband formation with the reef structures and solenoporaceans described in this paper is about 60 km northeast of esfahan, south of the road from esfahan to ardestan (fig. 1). the locality can be reached by car from esfahan geologia croatica geologia croatica 61/2–3 136 by taking the small side-road on the right after the town of komschetsche. the locality is 7 km from the turn-off, at the base of the escarpment, on the left side of the road. the stratigraphic section (fig. 2) is well exposed in ridge “2” shown in pl. 1, figs. a–c. the triassic nayband formation (about 130 m thick), forms the lower part of the section, and is overlain by lower jurassic beds and orbitolina-bearing cretaceous limestone (barremian), the latter forming the main part of the escarpment (pl. 1, fig. 1). the lowermost part of the nayband formation, about 26 m thick, is concealed by a talus of reef boulders containing mainly small hypercalcifi ed sponges and tabular spongiomorphids. coral-bearing bo ulders are not abundant. the exposed nayband formation succession starts with about 5.5 m of sponge-coral-dominated reef limestone passing up into about 9 m of coral-sponge-dominated, bedded, reefal limestone. this unit is overlain by 7.5 m of bedded reefal limestone in which the dominant organisms are small sphinctozoan sponges. this in turn is overlain by a limestone bed 2.7 m thick containing mainly tabular spongiomorphids which passes up into thick-bedded and sponge-dominated reefal limestone about 8 m thick. bioclastic limestone, 1.5 m thick, overlies the spongimorphid bed. this unit is overlain by bedded, sponge-dominated, reefal limestone about 21 m thick which passes up into a 6 m thick sequence of shaley sandstone beds which become calcareous in the upper part. the sandstone beds are overlain by a 1 m thick bed containing small brachiopods, and this passes up into about 10 m of fi gu re 1: geographic position of the locality south of the town of dizlu, northeast of esfahan (modifi ed from senowbari-daryan & hamedani, 2000). sponge-dominated, reef limestone. that is overlain by about a 1.5 m thick, solenoporacean-dominated bed with some spong es and then a 2.5 m thick unit of spongiomorphid beds. these last fossiliferous beds containing the spongimorphids are overlain by about 30 m of lower jurassic deposits comprising in terbedded shales and sandstone without macrofossils. the lower part of the nayband formation in ridge “1” (see pl. 1, figs. a–b) is not well exposed. the upper part of the section, however, does crop out and at the base of a sandstone unit the solenoporacean reefal build-ups reach a thickness of about 17 m. 3. systematic palaeontology phylum rhodophycophyta pappenfuss, 1946 class rhodophyceae ruprecht, 1851 family solenoporaceae pia, 1920 genus solenopora dybowski, 1878 remarks: according to riding (2004) the type species of solenopora (s. spongioides) from the ordovician is not a red alga but a chaetetid sponge. therefore a careful revision of all species described as solenopora is needed and a new generic fi gu re 2: columnar section of the nayband formation and overlying lower jurassic rocks through ridge ‘2’ shown in pl. 1, fig. 2. the basal 26 m of the nayband formation is not exposed. it starts with spongedominated, thick bedded to massive limestones. arrow indicates the solenoporacean horizon. geologia croaticababa senowbari-daryan et al.: new solenoporaceans from upper triassic (?norian-rhaetian) reef limestones in central iran 137 name for the true algal solenoporaceans should be proposed. meanwhile, the current generic name solenopora is used here to describe the solenoporacean species from iran. the following terms: main stem, branches of fi rst, second and third orders were used to describe the thallus of s. rectangulata in detail. these terms are shown in a thallus illustrated in fig. 3. solenopora rectangulata n. sp. (figs. 3–5; pl. 2, figs. a–b; pl. 3, figs. a–b; pl. 4, figs. a–c; pl. 5, figs. a–e; pl. 6, figs. a–e) derivatio nominis: rect (lat.) = rect, angulus (lat.) = angle. named for the rectangular branching pattern holotype: the individual thallus illustrated in pl. 4, fig. b/h is designated as the holotype (magnifi cation from pl. 4, fig. a, and compare fig. 4). paratypes: all specimens are illustrated in pl. 3, figs. a–b; pl. 4, figs. a–c; pl. 5, figs. a–e; pl. 6, figs. a–e. locus typicus: see fig. 1. stratum typicum: upper triassic, most probably rhaetian. diagnosis: erect, slender and multi-branched, antleror fi r-tree-like thallus. several branches may radiate outward from the same level on the main stem and when viewed from above the angle between the branches varies from 30 to 90 degrees. the net-like appearance of the thalli in side view can be recognized in the fi eld and in thin-section, and results from lateral branches (i.e. branches from the side branches) tending to grow parallel to the main stem. orientation of cells in the main stem and in the branches is different. no recognizable cross partitions. material: in numerous rock samples and in thin-sections numbered 2/1, 2/2, 5, 6, 10, 11, 12, 13, 14/1, 14/2, and 16 description: colonies of erect and slender thalli of this gregarious species reach lengths of up to 10 cm with lateral extensions of 30 cm and more. usually this species occurs alone (pl. 3, figs. a–b), but may also occur together with parachatetes dizluensis n. sp. (pl. 2, figs. a–b). this alga builds communities occupying surfaces of several square metres. even in the fi eld this alga is easily distinguished from the fi gu re 3: terms, used to described the thallus (drawn from plate 3, fig. b: rectagle) of solenopora rectangulata n. sp. in detail. legend: m) main stem, 1) branches of fi rst order, 2) branches of second order, 3) branches of third order. fi gu re 4: solenopora rectangulata n. sp. drawn from pl. 4, fig. b, this sketch shows the branching pattern of the alga and the large micritefi lled cavities within the axial part of the thallus, interpreted as borings or the result of diagenesis. legend: m) main stem, s) branches of fi rst order, t) branches of second order. scale: 2 mm. fi gu re 5: reconstruction of solenopora rectangulata n. sp. showing the branching pattern of the thalli approaching an angle of 90 degrees. legend: m) main stem, large arrows – branches of fi rst order, small arrows – branches of second order, smallest arrows – branches of third order. schematic, not to scale. geologia croatica geologia croatica 61/2–3 138 plate 1 a field overview of the locality. the top of the siliciclastic nayband formation at the base of the section is marked with a dark line. it extends laterally for approximately 1000 m and is overlain by lower jurassic deposits. the upper part of the escarpment is formed of orbitolina-bearing limestones of cretaceous (barremian) age. numbers 1 and 2 indicate the two ridges of reefal carbonates with solenoporaceans described in this paper. b closer view of the two ridges, shown in fi g. a above. the white line shows the route of the sampled section illustrated in fig. 2. c side view (from the north) of ridges 1 and 2 shown in fi gs. a–b above. outcrops of the nayband formation in siliciclastic facies are shown in the foreground. geologia croaticababa senowbari-daryan et al.: new solenoporaceans from upper triassic (?norian-rhaetian) reef limestones in central iran 139 geologia croatica geologia croatica 61/2–3 140 plate 2 a field photograph shows numerous large, multi-branched thalli of parachetetes dizluensis n. sp. and small, net-like thalli of solenopora rectangulata n. sp. b enlargement of part of fig. a above (marked by the rectangle) showing parachaetetes dizluensis n. sp. with large thalli (large arrows) and solenopora rectangulata n. sp. with small and net-like thalli (small arrows). geologia croaticababa senowbari-daryan et al.: new solenoporaceans from upper triassic (?norian-rhaetian) reef limestones in central iran 141 geologia croatica geologia croatica 61/2–3 142 plate 3 a field photograph shows numerous multi-branched, mostly antler-like thalli of solenopora rectangulata n. sp.. the scale is shown by the lens at the bottom right-hand corner. b photograph of a specimen with numerous parallel-growing and antler-like thalli of solenopora rectangulata n. sp. in their in situ position showing the branching nature of the thalli. geologia croaticababa senowbari-daryan et al.: new solenoporaceans from upper triassic (?norian-rhaetian) reef limestones in central iran 143 geologia croatica geologia croatica 61/2–3 144 plate 4 figs. a-c: solenopora rectangulata n. sp. a thin-section photograph showing numerous branched and parallel-growing thalli with the almost constant diameter of the main stems. several geopetal fabrics (large arrows) indicate the in situ position of the thalli. small arrows indicate the branches of neighbouring thalli growing or fused together. for an enlargement of the holotype (h) and the part shown by the rectangle, see fi g. b. thin-section 6. b close-up from fi g. a (rectangle) shows three multi-branched thalli. arrows indicate the branches of neighbouring thalli growing together. legend: h) holotype m) main stem, f) branches of fi rst order, s) branches of second order. c section through a thallus with branches of fi rst and second order. legend: m) main stem, f) branches of fi rst order, s) branches of second order. thin section 2. geologia croaticababa senowbari-daryan et al.: new solenoporaceans from upper triassic (?norian-rhaetian) reef limestones in central iran 145 geologia croatica geologia croatica 61/2–3 146 plate 5 figs. a–e: solenopora rectangulata n. sp. a longitudinal section through numerous thalli growing parallel to each other. the branching angle varies from 30 to 90°, mostly from branching points on opposite sides of the main stem. thin section 16. b longitudinal section through a multi-branched, antler-like thallus. legend: m) main stem, f) branches of fi rst order, s) branches of second order. thin section 12. c longitudinal section through two thalli with branching angles approaching 90°. numerous micrite-fi lled tube-like cavities in the axial part of the main stem run more or less parallel to the growth direction. these cavities may be interpreted as “fi laments” of the hypothallus in halymedaceans. because these tubes cut the cells and the concentric layers, they are interpreted as the result of boring by certain organisms or even as the result of diagenesis. the large arrow points to the cells in a lateral branch, bending upward and oriented almost parallel to the main stem. geopetal fabric in a brachiopod shell indicates the in situ growth position of the alga. thin section 6. d section through the branching point of a thallus showing the micrite-fi lled tubes (partly branched in the growth direction) in the axial part of the main stem and at the base of a branch. thin section 6. e numerous micrite-fi lled tubes, interpreted as borings or result of diagnesis, are oriented irregularly within a thallus. thin section 6. geologia croaticababa senowbari-daryan et al.: new solenoporaceans from upper triassic (?norian-rhaetian) reef limestones in central iran 147 geologia croatica geologia croatica 61/2–3 148 plate 6 figs. a–e: solenopora rectangulata n. sp. scale in all fi gs. is 1 mm. a section through two main stems with fi rst branches amalgamated together without a recognizable boundary. micrite fi lled large tube-like structures are the result of borings or even diagenesis. thin section 6. b close-up from fi g. a (rectangle) shows the amalgamated area (arrow) without recognizable boundary. c view similar to fi g. a exhibiting two main stems with fi rst branches amalgamated together without a recognizable boundary. thin section 6. d arrow indicates the amalgamated area of two fi rst-order branches. e the fi rst-order branches of a thallus (right side in photograph) penetrate into the main stem (left side in photograph) and are amalgamated with the stem without a recognizable boundary. large micrite fi lled tubeor hoselike cavities – partly branched (arrow) – that are interpreted as the result of borings or diagenesis due to penetration of the growth bandings, thus destroying them. thin section 6. geologia croaticababa senowbari-daryan et al.: new solenoporaceans from upper triassic (?norian-rhaetian) reef limestones in central iran 149 geologia croatica geologia croatica 61/2–3 150 companion species p. dizluensis n. sp. by its small thalli and particularly by the net-like appearance when viewed from the side (figs. 4–5; pl. 3, figs. a–b; pl. 4, figs. a–c; pl. 5, figs. a–c). individual thalli are more or less cylindrical and grow parallel to other individuals; the thallus diameter (diameter of main stem) does not increase during the growth stages (pl. 4, fig. a; pl 5, fig. b). branches of the fi rst and second orders (see fig. 3) diverge from the main stem at varying distances and may radiate from one or all sides (figs. 4–5; pl. 3, figs. a–b; pl. 4, figs. a–c; pl. 5, figs. a–c). by branching from a number of points on the main stem, the alga has the appearance in side-view of a fi r-tree (fig. 5). some of the secondary branch es taper towards their terminations as shown in fig. 5. the tendency of secondary branches (i.e. branches from the side branches) to grow parallel to the main stem produces a cha racteristic net-like appearance when viewed laterally (pl. 2, figs. a–b; pl. 4, fig. a). branches of neighbouring thalli may grow or fuse together, with or without recognizable boundaries (pl. 4, figs. 4a–b: small arrows; pl. 6, figs. a–e). individual thalli usually reach a diameter of 2 to 3 mm. the diameter of the main stem remains almost constant and does not increase during the growth stages. hoseor tube-like, partly branched and micrite-fi lled cavities were observed in the main stems of several individuals (fig. 4; pl. 5, figs. c–e; pl. 6, fig. e). these cavities are oriented more or less parallel or oblique and are usually branched upwards. they could be interpreted as "fi laments" of a hypothallus in halymedacean algae. the maximum diameter of these tube-like cavities is 0.07 mm but as they approach the periphery of the thallus they decrease to about 0.02 mm, i.e. approximately the cell diameter of the alga. we interpret these tube-like cavities as secondary products (the result of boring or diagenesis,). pronounced recrystallization makes recognition of cell details impossible in most specimens, but in well preserved thalli a weak annual growth banding is recognizable. the larger tube-like cavities pass through the cells and appear to destroy those (pl. 6, fig. e). the holotype (pl. 4, fig. b/h) is a multi-branched specimen reaching a height of 22 mm. it exhibits all the characteristics of the alga, in particular its branching pattern and antler or fi r-tree-like appearance. fig. 5 shows a reconstruction of s. rectangulata n. sp.. discussion: the larger (about 0.07 mm diameter) hose or tube-like and micrite-fi lled cavities in the axial region of the main stems of solenopora rectangulata n. sp. and at the base of the branches might be interpreted as borings of microorganisms, or else as cells of thallus differentiation in this alga, or even as “fi laments” of a hypothallus in halymedaceans. if the latter, this feature would justify the assignment of this alga to the halymedaceans. several features would support the interpretation of these tube-like cavities as cells or “fi laments” of halymedaceans: a) the micrite-fi lled tubes are concentrated in the axial region of the main stem and in the base of the branches and are rare in the peripheral part of the main stem; b) the cavities are oriented more or less parallel to the axis of the main stem or its branches; and c) branching directions of the tubes are ma inly consistent with the growth direction of the thallus. alternatively, the following features would support an interpretation of the micrite-fi lled tube-like cavities as the result of borings or diagenesis: a) the micritic cavities cut and appear to have destroyed the concentric structure produced by annular growth banding of the thallus (pl. 6, fig. e); b) the micritic cavities are without their own walls, c) there is no recognizable differentiation between the hypoand perithallus in the alga. table 1: characteristics of triassic species of solenopora, including s. alcicornis ott, 1966 (carnian-rhaetian), s. endoi flügel, 1975 (norian-rhaetian), s. isoconcentrica senowbari-daryan et al., 2007 (anisian), s. karaburunensis (= parachatetes karaburunensis düzbastilar, 1976) (anisian-ladinian), s. paraconcentrica senowbari-daryan et al., 2006 (anisian), s. simionescui dragastan, 1969 (ladinian), s. styriaca flügel, 1960 (rhaetian), s. triasina vinassa de regny, 1915 (norian), s. undata senowbari-daryan & link, 2005 (norian), s. vachardi senowbari-daryan et al., 2006 (anisian), s. zlambachensis flügel, 1962 (rhaetian). legend: cd – cell diameter, tcw – thickness of the cell walls, co – cell outline (in cross section), m – morphology of the thallus. all measurements in µm. modifi ed from senowbari-daryan et al. (2006). *) the original species name solenopora concentrica (senowbari-daryan et al., 2006) has been changed to solenopora isoconcentrica by senowbari-daryan et al. (2007). species cd tcw co m s. alcicornis 15–50 8 polygonal antler-like s. endoi 20–30 12–15 (–24) circular-oval nodular, branched s. isoconcentrica* 40 10–20 circular-oval hemispherical s. karaburunensis 52–156 3–10 ? ? s. paraconcentrica 20 10 ? hemispherical s. rectangulata n. sp. 20 20 circular-oval fir-tree-like s. simionescui 30–45 ? circular-oval lobed, fan-like s. styriaca 30–80 5–10 circular-oval nodular s. triasina 50–70 (–150) ? polygonal conical s. undata 30–80 10–15 circular-polyg. nodular s. vachardi 20–30 5–8 ? erect, branched s. zlambachensis 9–21 ? polygonal nodular-cylindrical geologia croaticababa senowbari-daryan et al.: new solenoporaceans from upper triassic (?norian-rhaetian) reef limestones in central iran 151 we interpret the micrite-fi lled large cavities within the thalli as borings of micro-organisms or even as result of dia genesis. these structures are oriented along the weakly calcifi ed direction, which runs parallel to the cell walls, and are not perpendicular to them. this interpretation justifi es our as signing this alga to the solenoporaceans. remarks: all species of the genus solenopora, known from triassic deposits are listed with their diagnostic features in table 1. all of these solenoporacean species have a nodular or club-shaped thallus. only the antler-like multi-branched species solenopora alcicornis ott (1966) is comparable with this new species from iran. the branching pattern (fi nger-like in s. alcicornis, fi r-tree-like in s. rectangulata) and the small size of the thallus clearly distinguish the iranian species s. rectangulata from the carnian species s. alcicornis ott. genus parachaetetes deninger, 1906 parachaetetes dizluensis n. sp. (figs. 6–7; pl. 2, figs. a–b; pl. 7, figs. a–c; pl. 8, figs. a–c) derivatio nominis: named for the small town of dizlu, to the northwest of the type locality. holotype: multi-branched thallus illustrated in pl. 7, fig. a/h (thin section 9). paratypes: all specimens illustrated in pl. 2, figs. a–b; pl. 7, figs. a–c; pl. 8, figs. a–c. locus typicus: see fig. 1. stratum typicum: upper triassic, most probably rhaetian. diagnosis: erect and fi nger-like multi-branched thallus with a diameter up to 8 mm (at branching points up to 16 mm). cells are oriented in the middle part of the thallus parallel to the axis, but toward the periphery of the thallus they diverge at an angle of 30o-90o. concentric layers about 0.1 mm apart are produced by the thickening of the cell walls at the same height. other kinds of cross partitions are missing. cells are round or polygonal with a diameter of 0.04 mm. reproductive organs were not observed. material: numerous thalli in thin sections 2/0, 3, 4, 8, 9 (holotype), 13, k60. description: the erect and large thalli of this alga can easily be mistaken in the fi eld for recrystallized dendroid cor als of a similar diameter. this alga grew together with solenopora rectangulata n. sp. in patches several square metres in diameter. the thallus of this fi nger-like multi-branched alga reaches heights of up to 20 cm with lateral extensions up to 20 cm long. the thallus of the holotype is at least 9 cm high with lateral extensions of at least 13 cm. the holotype (pl. 7, fig. a/h) is a multi-branched thallus with a length of at least 9 cm and with a diameter of 13 mm at branching points. the diameter of individual branches is usually 8 mm, reaching diameters of up to 16 mm at the branch ing points. in cross-section the cells are round to polygonal and have a maximum diameter of 0.04 mm (0.02–0.04 mm). concentric layers, produced by the thickening of the cell walls, are clearly visible in the axial parts of the thallus but not well developed in the peripheral parts. the concentric layers are a fairly constant 0.1 mm apart. the thickness of the cell walls is about 0.02 mm. thalli are generally recrystallised, particularly in the axial region. peripheral parts are locally well preserved and may exhibit a thickening of the cell walls (pl. 7, fig. c; pl. 8, fig. b). this thickening is mainly on one side of the cell wall and the concentric layers are then indistinct or even absent (fig. 6). in the axial region the cell walls are thickened on both sides fi gu re 6: a) sketch showing the "water jet" orientation of cells in a thallus of parachaetetes dizluensis n. sp. b) curved cell walls and thickening on one side at the periphery of the thallus. c) thickening of the cell wall on both sides in the axial region of the thallus causing the concentric layers of the thallus. schematic, not to scale. fi gu re 7: reconstruction of parachaetetes dizluensis n. sp. showing the fi nger-like branching pattern of the alga. schematic, not to scale. geologia croatica geologia croatica 61/2–3 152 plate 7 figs. a–c: parachaetetes dizluensis n. sp. a longitudinal section through a colony of numerous thalli showing the fi nger-like branching pattern of individual thalli. h) holotype. thin section 9. b enlargement of the axial part of a thallus showing the cells and the thickening of the cell walls at the same level producing the concentric layers. thin section 2/0. c longitudinal section at the edge of a thallus showing the thickening of the cell walls at the same level producing the concentric layers. thin section 2/0. geologia croaticababa senowbari-daryan et al.: new solenoporaceans from upper triassic (?norian-rhaetian) reef limestones in central iran 153 geologia croatica geologia croatica 61/2–3 154 plate 8 figs. a–c: parachaetetes dizluensis n. sp. a longitudinal section through numerous thalli showing the fi nger-like branching pattern of individual thalli. enlargements of the marked rectangles are shown in fi gs. b and c (rotated approx. 90° clockwise). thin section k60. b enlargement from fig. 8a (quadrangle 1) showing the wavy cells and the concentric running growth lines in longitudinal section, produced by the thickening of the cell walls. thin section k60. c enlargement from fi g. a (quadrangle 2). for explanation see fi g. b. thin section k60. geologia croaticababa senowbari-daryan et al.: new solenoporaceans from upper triassic (?norian-rhaetian) reef limestones in central iran 155 geologia croatica geologia croatica 61/2–3 156 producing the concentric layers. cell partitions (except the thickenings) are lacking. a schematic reconstruction of the thallus of p. dizluensis n. sp. is shown in fig. 7. remarks: the triassic species of parachaetetes were revised by senowbari-daryan & link (2005) and according to those authors the following species of parachaetetes can be assigned a triassic age: parachaetetes marii (= lithothamnidium marii moiseev, 1944), p. maslovi flügel, 1975, p. cassianus (solenopora cassiana flügel, 1961), and p. rhaeticus dragastan et al., 2000. additionally the species p. clatratus, p. riedeli, and p. tauricus were described from norian reef boulders in the taurus mountains of southern turkey by senowbari-daryan & link (2005). algae with erect and branched thalli – like p. dizluensis – are known from other upper triassic localities. the growth pattern and multi-branched thallus of parachaetetes tauricus senowbari-daryan & link (2005) is very similar to p. dizluensis n. sp., but it differs from this iranian species by its smaller thallus diameter, wider spacing (0.6–0.8 mm) of its concentric layers and by its rounded cell outlines. in addition the concentric layers, refl ecting the thickening of the cell wal ls, are much better developed in p. tauricus and other species than in this iranian species. thickening of one side of the cell walls in p. dizluensis was not observed in other species of the genus. different degrees of thickening of the cell walls in the axial and peripheral regions may refl ect the beginning of differentiation of the hypoand perithallus. such differentiation was also interpreted by pia (1939) for the tertiary species parachaetetes asvapatii and for the triassic species solenopora alcicornis by ott (1966). p. asvapatii, however, differs from p. dizluensis by well thickened cell walls and wider spacing of its concentric layers (see moussavian, 1989, pl. 5, fi gs. 3-4). multi-branched pattern of the thallus in p. dizluensis and the stratigraphic range are further differences to p. asvapatti. for comparison, the diagnostic features and dimensions of p. dizluensis n. sp. and other species of parachaetes, known from triassic deposits, are listed in table 2. 4. organism associations and microfacies in the sponge-coral dominated reefal parts of the succession, only a few individual thalli of the two species of algae des cribed here occur. in the upper part of the section both algae occur, either alone or together, in algal patches, usually without any other reef builder. several instances of geopetal fabrics (pl. 4, fig. 1; pl. 7, fig. 1) indicate the in situ growth position of the algae. spaces between the thalli are fi lled with micrite, indicating a quiet environment with limited water currents. in the sediment between the thalli, small foraminifera including different species of trocholina sp., seminivoluta sp., and coronipora sp. occur, along with rare small miliolids (galaenella sp., “sigmoilina” sp., ophthalmidium sp.), brachiopods (including gosaukammerella eomesozoicum (flügel)), gastropods and ammonites. an epifauna comprising sessile foraminifera and a few worm tubes was noted. the foraminiferal association of the investigated material in this locality differs from other localities of the nayband formation and will be published separately. a number of the foraminifera which occur here range up into the lower jurassic of the te thy an realm but the association indicate late triassic for this section. other organisms include hypercalcifi ed sponges (mainly small species), corals and other reef organisms. solenoporaceans occur in reefs together with other reef builders in the upper triassic nayband formation at other localities in central and northeast iran. however, reefal buildups composed solely or mainly of algae, or where solenoporaceans are so abundant, have not been described before from the nayband formation. moreover, such algal constructions are not known from any other triassic localities in the world. the multi-kilometre sized solenomeris reefs in the pyrenean domain (s. france, n. spain) are not classifi ed as algal reefs. solenomeris, a taxon previously interpreted as a solenoparcean alga, is nowadays assigned to encrusting foraminifera (per rin, 1987; plaziat & perrin, 1992; moussavian & höfling, 1993). therefore the solenoporacean reefal structure in iran seems to be a unique algal construction. acknowledgement the investigations were carried out under the terms of the research project “stratigraphische, paläoökologische, paläontologische und fazielle bearbeitung eines obertriassisch-liassischen? riffes im zentraliran, se 416/17–1”. michael ridd (london) is gratefully acknowleged for the english correction of the text. this paper benefi ted from the constructive reviews of ovidiu dragastan (bucharest) and an anonymous review er. table 2: characteristics of triassic species of parachaetetes, including p. cassianus (= solenopora cassiana flügel, 1961) (carnian), p. clatratus senowbari-daryan & link, 2005 (norian), p. marii (= lithothamnidium marii moiseev, 1944) (norian), p. maslovi flügel, 1975 (norianrhaetian), p. rhaeticus dragastan et al., 2000 (rhaetian), p. riedeli senowbari-daryan & link, 2005 (norian), p. tauricus senowbaridaryan & link 2005 (norian). legend: cd – cell diameter, tcw – thickness of the cell walls, co – cell outline (in cross section), dcl – distance apart of concentric layers. all measurements are in µm. modifi ed from senowbari-daryan et al. (2006). species cd tcw co dcl p. cassianus 50–100 25 polygonal 40–420 p. clatratus 50–120 60–80 polygonalcircular 40–350 p. dizluensis n. sp. 20–40 20 polygonalcircular 100 p. marii 50 5 polygonal 100 p. maslovi 18–35 6–12 polygonalangular 50–300 p. rhaeticcus 12–20 ? circular 24–40 p. riedeli 30–40 ~10 circular 40–100 p. tauricus 30–50 ~10 circular 60–80 geologia croaticababa senowbari-daryan et al.: new solenoporaceans from upper triassic (?norian-rhaetian) reef limestones in central iran 157 references deninger, k. (1906): einige tabulaten und hydrozoen aus mesozoischen ablagerungen. – n. jb. mineral. geol. paläont., 1, 61–70. dragastan, o. (1969): triassic calcareous algae from the apuseni mountains (rumania). – rev. palaeobotan. palynol., 1969, 63–101. dragastan, o., kube, b. & richter, d.k. (2000): new late triassic calcareous algae from hydra, greece. – acta palaont. romaniae, 2 (1999), 139–156. düzbastilar, m.k. (1976): parachaetetes karaburunensis n. sp., ortonella germiyanensis n. sp., two new species from triassic of central part of the karaburun peninsula. – sci. rep. faculty sci. ege univ., 239, 3–12. dybowsky, w. (1878): die chaetetiden der ostbaltischen silur-formation. – russ. kais. mineral. ges. st. petersburg verh., ser 2, 14 (1878), 1–134. flügel, e. (1960): solenoporaceen (algen) aus den zlambach-schichten (rhät) der fischerwiese bei alt-aussee, steiermark. – n. jb. geol. paläont., mh., 1960/8, 339–354. flügel, e. (1961): algen (solenoporaceen) aus den cassianer-schichten (ober-ladin) der südalpen. – n. jb. geol. paläont., mh., 1961 (7), 339–345. flügel, e. (1962): beiträge zur paläontologie der nordalpinen riffe. neue spongien und algen aus den zlambach-schichten (rhät) des westlichen gosaukammes, oberösterreich. – ann. naturhistor. mus. wien, 65, 51–56. flügel, e. (1975): kalkalpgen aus riffkomplexen der alpin-mediterranen obertrias. – verh. geol. b-a. wien, 1974 (2/3), 297–346. fürsich, t. f., hautmann, m., senowbari-daryan, b. & seyed-emami, k. (2005): the upper triassic nayband and dark uh formation of east-central iran: stratigraphy, facies pattern and biota of extensional basins on an accreted terrane. –beringeria, 35, 53–134. moissev, a.d. (1944): algae, sponges, aqueous polyps and corals of the upper triassic of the caucasus. – uchenye zapiski leningradskogo gosaudarstvennogo universiteta, ser. geologo-pochvennogeeografi chskaya, 11(70), 1–28 [in russian]. moussavian, e. (1989): über die systematische stellung und die bestimmungskriterien der solenoporaceen (rhodophyceae). – cour. forsch.-inst. senckenberg, 109, 51–91. moussavian, e. & höfling, r. (1993): taxonomische position und palökologie von solenomeris douvillé, 1924 und ihre beziehung zu acervulina schultze, 1854 und gypsina carter, 1877 (acervulinidae, foraminiferida). – zitteliana, 20, 263–276. ott, e. (1966): zwei neue kalkalgen aus den cassianer schichten südtirols (oberladin, mittlere trias). – mitt. bayer. staatssamml. paläont. hist. geol., 6, 155–166. pappenfuss, g.f. (1946): proposed names for the phyla of algae. – bull. torrey botanic club, 73, 217–218. perrin, c. (1987): solenomeris, un foraminifère acervulinidae constructeur de récifs. – rev. micropaléontol., 30/3, 197–206. pia, j. (1920): siphoneae verticillatae vom karbon bis kreide. – abh. zool.-botan. ges. wien, 11/2, 1–263. pia, j. (1939): sammelbericht über fossile algen: solenoporaceae 1930 bis 1938, mit nachträgen aus früheren jahren.n. jb. min. geol. paläont, 1939/iii, 731–760. pliaziat, j.-c. & perrin, ch. (1992): multikilometer-sized reefs built by foraminifera (solenomeris) from the early eocene of the pyrenean domain (s. france, n. spain): palaeoecologic relations with coral reefs. – palaeogeogr., palaeoclimat., palaeoecol., 96 (1992), 195–231. riding, r. (2004): solenopora is a chaetetid sponge, not an alga. – palaeontology, 47, 115–112. ruprecht, f. j. (1851): über das system der rhodophyceae. – mém. acad. imp. sci., st. pétersbourg, 7, 1–30 (=25–54). senowbari-daryan, b. (1996): upper triassic reefs and reef com munities of iran. – in: reitner, j., neuweiler, f. & gunk el, f. (eds.): global and regional controls on biogenic sedimentation i. reef evolution, research report. göttinger arb. geol. paläont., sb. 2, 299–304. senowbari-daryan, b. (2005a): hypercalcifi ed sphinctozoan spong es from upper triassic (norian-rhaetian) reefs of the nayband formation (central and northeast iran). – jb. geol. b-a. wien, 145/2, 171–277. senowbari-daryan, b. (2005b): neue inozoide schwämme aus obertriassischen (nor-rhät) riffen der nayband-formation (zentraliran). – senckenbergiana lethaea, 85/2, 261–299. senowbari-daryan, b. hamedani, a. (1999): girvanellid coated udoteacean oncoids from upper triassic (norian-rhaetian) nayband formation near the towns of khaneh-khoreh and wali-abad, south of abadeh (central iran). – rev. paléobiol., 18/2, 597–606. senowbari-daryan, b. & hamedani, a. (2000): obertriadische (nor) dasycladaceen aus der nayband-formation vom zentraliran. – rev. paléobiol., 19/1, 97–121. senowbari-daryan, b. & link, m. (2005): solenoporaceen aus den obertriassischen (nor) riffkalken des taurusgebirges (antalya-gebiet, südtürkei). – paläont. z., 79/4, 409–427. senowbari-daryan. b., link, m. & isintek, i. (2006): calcareous algae from the triassic (anisian reef boulders and norian reef limestones) of karaburun, western turkey. – facies, 52, 129–148. senowbari-daryan, b., link, m. & isintek, i. (2007): a new name for triassic algal species solenopora concentrica senowbaridaryan, link & isintek 2006. – facies, 53, 127. seyed-emami, k. (1971): a summary of the triassic in iran.geol. surv. iran, report 20, 41–53. seyed-emami, k. (2003): triassic in iran. – facies, 48, 91–106. vinassa de regny, p. (1915): triadische algen, spongien, anthozoen und bryozoen aus timor. – in wanner, j. (ed.): paläontologie von timor, lieferung 4, teil 8, 75–118. manuscript received november 9, 2007 revised manuscript accepted may 19, 2008 gc 58-1.indb qualitative–quantitative analyses of the influence of depth and lithological composition on lower pontian sandstone porosity in the central part of bjelovar sag (croatia) tomislav malvić1, josipa velić2 and zoran peh3 1. introduction reservoir characterization mostly comprises detailed evaluation of petrophysical parameters, i.e. porosity, permeability and saturation. accuracy depends on the source, amount of data, and method applied for their comparison and evaluation in places where the parameters are not measured. porosity is selected as the most important variable for reservoir characterization as it has a direct influence on permeability and saturation values. input data were porosity values measured in vertical cores, performed in the ina-naftaplin laboratory and noted in well files. also, data are selected and classified regarding their (litho)stratigraphic position in a database (malvić, 2003a). the majority of the data in bjelovar sag (sw margin of pannonian basin), belongs to the pepelana and poljana sandstones (kloštar-ivanić formation, of approximate lower pontian age, figs. 3 and 4). these units were chosen for analysis because they occur in the central part of the sag. the analysed cores have different lengths, number and position of measurements. for previous geostatistical (variogram) analyses (malvić, 2003a, b), only cores where it was possible to select a minimum of 10 intervals of 0.25 m or 0.5 m were used. in intervals with several measurements the mean value was calculated. each interval was represented by a single calculated value in order that equal importance could be given to intervals with low or high amounts of data. in intervals without data, interpolated porosity curves were constructed and the mean value determined from such curves. the same criteria are accepted in this analysis. the goal was to collect sufficient amounts of reliable and equally “valid” input data. “valid” means that it would be incorrect to give the same importance to a cluster of 8 values measured over 40 cm of core and of 5 values measured from perhaps the next 2 metres. reliability is a consequence of a selected core size, and is important for the calculation of representative interval values. the main aims of this paper are to: – apply graphical and statistical analysis to determine the range (depth difference), over which depth influ geologia croatica 58/1 73–85 6 figs. 6 tabs. zagreb 2005 key words: porosity, sandstones, lithological variability, oil reservoirs, calculation of average φ, t-test, f-test, pearson’s r, lower pontian, bjelovar sag, pannonian basin, croatia. 1 ina–industry of oil plc. (naftaplin), šubićeva 29, hr-10000 zagreb, croatia; e-mail: tomislav.malvic@ina.hr 2 faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, hr-10000 zagreb, croatia; e-mail: jvelic@rgn.hr 3 institute of geology, sachsova 2, hr-10000 zagreb, croatia; e-mail: zpeh@igi.hr abstract results of several tests (porosity–depth graphic relation, t-test, ftest, pearson’s r), were used to analyse and interpret the regularity in porosity values of lower pontian oil-bearing sandstones from the central part of bjelovar sag. data came from 7 cored intervals within 5 wells in the pepelana member and from 6 cored intervals (in 4 wells) in the poljana member. the expected porosity decrease with increasing depth was checked against lithological variations. sandstones are mostly fine-grained lithoarenites. the detritus is composed of quartz, various micas, carbonate fragments and feldspars. across the study area, the depth range of the sandstones varies from 430 m (top of the pepelana member near šandrovac) to 2046 m (base of the poljana member near velika ciglena). cores included in the analyses vary between 2.75 to 15.5 m in length. mean porosity and relative depth data were collected for two groups: group 1 comprised wells pav–1, pav–2, rov–1, ša–5, ša– 35, and group 2 included well vc–1. these groups were subdivided for analysis into two (litho)stratigraphic units (pepelana and poljana ss.). porosity variation within each group is explained with reference to the silt or clay fraction. differences between the porosities of the two groups (~10% lower absolute porosity near velika ciglena) is the result of compaction and other processes. interval of 400 m thickness in particular sandstone member is set as minimum value for observing influence of compaction. such statement is based on sandstone’s tops and bottoms comparison as well as graphical presentation of relation core porosity–relative depth interval. the analysis was improved by statistical calculation of pearson’s r, t-test and f-test, which more precisely described the relationship between porosity and depth. using these statistical tests and regression equitation, the depth difference is calculated as 621 m in the pepelana and 667 m in the poljana sandstones, as the limits when the influence of compaction in the porosity–depth relationship could be noticed. compaction was observed, in the study area, when data from velika ciglena are compared to data from the other wells. 74 geologia croatica 58/1 ences the decrease in porosity, for both the lower pontian poljana and pepelana sandstones, and – describe the range in porosity values, with regard to their depth of location. here, the t-test, f-test and areal comparison of porosity values from different locations and depths were used as the main analytical tools. the results are partially comparable with those of statistical analyses published by jüttner et al. (2000) and saftić et al. (2001). in these two papers porosity behaviour is also statistically analysed in rock units from the sava depression, which are lithostratigraphic equivalent to the lower pontian sandstones of the bjelovar sag. a comparison and discussion of the results is given in more detail below. additionally, some interesting results on the porosity behaviour and compaction influence in sedimentary rocks can be found in papers written by buryakovskiy et al. (1991) and reed et al. (2005). 2. delimitation of the analyzed area and basic geological settings the area explored is part of the pannonian basin system, which was covered by the paratethys palaeosea and deposits of younger lacustrine and fluvial environments (royden, 1988). the borders of this basin system, as the largest regional structural–stratigraphic unit, have been determined based on the extent of neogene sediments (fig. 1). the basin system comprises lower structural–stratigraphic units in a range of basins or depressions (in croatia these are the drava, sava, mura and slavonian–srijem depressions). the smallest regional units are named as sag or subdepression. the bjelovar sag, which is the southwestern branch of the drava depression, is such a subdepression (fig. 1). the study area covers the central part of the bjelovar sag (fig. 2), its borders being determined on the basis of a palaeorelief map after malvić (2003a). an unconformity between palaeozoic and mesozoic rocks in the palaeorelief and neogene sediments (“temeljno gorje” – tg, or “podloga tercijara” – pt) often comprises very characteristic forms (faults, “buried hills”, negatively inversed relief areas). the influence of this can also be observed in badenian, sarmatian, pannonian and sometimes even in younger sediments. this boundary was considered very useful for separation of particular blocks in regional units, which is also done here. borders of analysed block are represented by (clockwise from southwest) the 2300/2400 m isobates, the bilogora normal fault on the north, the 2500 m isobate north from this fault, and northeast from šandrovac, the 2800 m isobate to the east and the main reverse fault to the south (fig. 2). the following localities (with one or more wells), belong to analysed block and are approximately west to east: rovišće (well rov–1), galovac–pavljani (pav–1, pav–2), šandrovac (ša–5) and velika ciglena (vc–1). available cores produced 213 porosity values in total from intervals of 0.5 or 0.25 m (tables 1, 2) in the pepelana and poljana sandstones. the relatively large disfig. 1 main regional structural–stratigraphic units in pannonian basin system (after royden, 1988). 75malvić, velić & peh: qualitative–quantitative analyses of the influence of depth... tance between the rovišće and pavljani localities (fig. 2) is considered as a shortfall in the well net, because there is no data over distances greater than 15 km. basic geological, i.e. lithological characteristics, from the oldest to the youngest lithostratigraphic units, are shown in figs. 3 and 4 and described together with their dominant rock types. palaeozoic schists and middle triassic carbonates were drilled at nearby rovišće, a gneiss–granite complex by galovac–pavljani, and middle triassic carbonates and carbonate breccia in the velika ciglena wells. the pre-neogene basement is not clearly determined near šandrovac, because very few wells reached these rocks. it is supposed that the basement is mostly represented by carbonates in contact with palaeozoic schists on the south/southwest part of the field. neogene sediments were deposited over the entire area. they begin with the mosti member of the moslavačka gora fm. (approximately middle miocene age, including the sarmatian), composed of mostly marine facies including siliciclastic and carbonate breccia, conglomerates and sandstones. deepwater sediments with a prevalence of carbonate detritus and silt characterize the velika ciglena area, elsewhere siliciclastic detritus predominates. there is a fining-upward sequence from coarse-grained sediments into limestone. the younger križevci member (approximately of lower pannonian age) is represented by calcareous marlstones and clayey limestones. the ivanić-grad formation (approximately of upper pannonian age) was deposited in brackish environments of the closed lake. within this, the lipovac marlstone (missing at the top of galovac–pavljani structure, in well pav–1, fig. 3) is the oldest member, followed by the zagreb member (or lateral equivalent okoli sandstones in the velika ciglena area), both represented by repetitions of sandstones and marlstones. the kloštar-ivanić formation (of approximate lower pontian age) represents a lacustrine environment and is composed of a number of members. the oldest is the lepsić marlstone, medium hard and sporadically sandy in the upper part. it is overlain by the poljana sandstone, often marly or with pure marlstone intercalations. the graberje marlstone is a middle marly member, with localised sandy intercalations. the pepelana sandstone is the younger sandstone member. mostly composed of fine-grained, quartz-mica, medium hard content, it often contains clayey marlstones or marly clays intercalations. the youngest cabuna marlstone is represented by clayey marlstone or marly clay. fresh-water, lacustrine and deltaic environments represent the depositional setting of the bilogora formation (approximately of upper pontian age). this formation is not divided into members. generally, sediments are fig. 2 borders of the central bjelovar sag part determined from palaeorelief map. 76 geologia croatica 58/1 composed of marly clays, clays and sandstones, with a prevalence of impermeable or poorly permeable sediments. the youngest lonja formation (approximately of pliocene and quaternary age) was deposited in numerous fresh-water lakes, and (in the quaternary), in fluvial and swamp environments as well as on the land. marly clays, clays, sands, gravels and loess were deposited, and, close to the modern surface, unconsolidated holocene sediments. lower pontian sandstones were analysed with regard to their available depositional, granulometric and mineralogical data. all available cores were mostly taken from the most favourable parts of these reservoir units. these are lithologically very similar units – light grey, fine-grained, and mostly medium to very hard, quartz-mica sandstones, with different portions of silt and/or clay. all the studied units need to be observed in the context of the entire sag with respect to their environmental interpretation. malvić (2003a) gives a short review of the neogene depositional environments in the bjelovar sag, as a compilation of currently accepted interpretations of the entire croatian part of the pannonian basin. the author has mentioned that a significant part of the permeable sediments is mapped in the deepest parts. such sediments were probably transported by strong and multiple turbidity currents, which originated in the alps and flowed toward the southeast. the surrounding land was probably the source of a smaller proportion of material. such a transport mechanism of very dense turbidite currents, able to carry huge quantities of material for a hundred kilometres, has been described elsewhere, e.g. by tišljar (1994) and vrbanac (1996). normal, deepwater pelitic sediments, mostly marlstones, were deposited between the activities of such currents. turbidites were active periodically through subaqueous channels, probably of kilometre dimensions. the salinity of water changed from brackish to fresh (vrbanac, 1996; rögl, 1996, 1998), as indicated by the fauna found in the cores. the sedimentary environment is interpreted as part of a subaqueous channel, probably of kilometre dimensions. regarding the present-day depths and thickness, as well as the observed horizontal lamination in velika ciglena cores, the axis of the depositional channel runs through the areas of šandrovac and velika ciglena, striking in a northwest/southeast direction. rovišće and pavljani were located on its margin. the total thickness of the pepelana and poljana sandstones taken together is about 400–600 m in the central part of the channel (šandrovac and velika ciglena), and about 200–300 m on the margins (rovišće and galovac–pavljani). neogene pelitic sediments were deposited during specific periods in places with lower current energy, i.e. shallower or uplifted parts of sedimentational area (after šimon, 1980). intervals of particle diameters were determined from granulometric analyses (collected from well files rov– 1, pav–1, pav–2 and vc–1). these values, regarding the core, vary between 0.05–0.115 mm, 0.100 mm on average. analysis of particle sizes showed the prevalence pepelana pav–1 rov–1 ša–5 ša–35 vc–1 (a) vc–1 (b) vc–1 (c) (rel. depth (827– (≈1045.0– (≈430– (≈616.5– (1401–1715 m) of unit) 882 m) 1167.1 m) 820 m) 884 m) rel. depth of 850–856 1047–1053 680.3–687.3 797.7–810.2 1479.25–1482.5 1536–1542 1579–1583.5 anal. core (m) 810.6–816.6 averaging interval (m) 0.5 0.5 0.5 0.5 0.25 0.5 0.25 min.–max. φ (%) 17.9–31.0 7.7–33.1 28.1–33.1 15.4–31.4 8.4–16.4 13.6–16.0 6.9–25.6 arithmetical mean φ (%) 25.03 22.54 31.15 23.15 14.63 15.02 19.91 no. of data 12 12 26 51 13 12 18 table 1 descriptive statistics for the pepelana sandstones. poljana pav–1 pav–2 (a) pav–2 (b) rov–1 vc–1 (a) vc–1 (b) (rel. depth (911– (948–1195 m) (1190.9– (1748–2046 m) of unit) 1040 m) 1333.8 m) rel. depth of 913–928.5 977–986 1071–1075.5 1311–1316 1747–1751 1843.5–1846.25 anal. core (m) averaging interval (m) 0.5 0.5 0.5 0.5 0.25 0.25 min.–max. φ (%) 20.5–33.0 13.0–24.7 19.9–27.7 6.9–25.5 6.2–17.4 9.6–24.6 arithmetical mean φ (%) 27.17 20.44 25.23 21.43 12.58 16.39 no. of data 31 9 18 10 16 11 table 2 descriptive statistics for the poljana sandstones. 77malvić, velić & peh: qualitative–quantitative analyses of the influence of depth... of sand (about 70%), followed by coarse-grained silt (about 20%), with the remainder being fine-grained silt and clay. the fraction of particles less than 0.125 mm in diameter accounts for more than 50%. again, sand predominates with about 40–50 wt.%, followed by coarsegrained silt (about 15–25%) and a high proportion of calcite (about 30–35%). the rest is fine-grained silt and clay. there is a good degree of sorting. sandstones are classified as lithoarenites, according to their detrital origin. the mineral composition of the lower pontian sandstones was meticulously analysed in the cores of the well vc–1 (vlahović et al., 19914), and the following minerals were determined: quartz, various micas (muscovite, sericite, chlorite and biotite), rock fragments (mostly carbonate, lesser low-grade metamorphic schists) and feldspars. accessory minerals described included zircon, tourmaline, opâque minerals and (rarely) glauconite. the intergranular space is filled with ferroan and calcite cement, and sporadically with organic matter. horizontal lamination observed at velika ciglena is a result of grain size variations as well as an fig. 3 lithostratigraphic correlation section rovišće–pavljani– velika ciglena. 4 vlahović, t., stanković, d., raškaj, n. & ban, d. (1991): biostratigrafija, litofacijesi i okoliši sedimentacije bušotine vc–1 [biostratigraphy, lithofacies and depositional environments of the vc–1 well – in croatian].– unpublished report, archive of ina-naftaplin professional documentation, zagreb. 78 geologia croatica 58/1 increase in the proportion of mica minerals/organic matter. the well ša–5 was completed in 1964 and this is why some lithostratigraphic borders are only assumed (fig. 4). at that time stratigraphic units were described according to the biostratigraphic nomenclature (rhomboidea-, abichi-, banaticaand croatica-strata). documentation of the informal lithostratigraphic data of particular members and reservoirs (pools) was rare. at the end of the nineteen-sixties, biostratigraphic units started to be replaced with lithostratigraphic units of formation range, which were approximately co-depositional. at the same time, standard procedures during geological observation also comprised determination of lithostratigraphic members. the first comprehensive lithostratigraphic nomenclature for the croatian part of the pannonian basin was introduced by šimon in 19685. fig. 4 lithostratigraphic correlation section šandrovac–velika ciglena. 5 šimon, j. (1968): informativne litostratigrafske jedinice tercijarnog kompleksa u profilima dubokih bušotina na području dravske potoline [informative lithostratigraphic units of the tertiary complex in profiles of deep wells in the drava depression – in croatian].– unpublished report, archive of ina-naftaplin professional documentation, zagreb. 79malvić, velić & peh: qualitative–quantitative analyses of the influence of depth... it is important to mention the work of velić et al. (2002) where neogene lithostratigraphic formations are divided into 3 depositional megacycles of the second order. each of these megacycles is composed of clearly recognisable lithological units corresponding to formations and members. according to the drava depression nomenclature, the 1st depositional megacycle comprises the oldest miocene sediments including the sarmatian, i.e. the mosti member. the 2nd depositional megacycle comprises the križevci member as well as the ivanićgrad, kloštar-ivanić and bilogora formations, i.e. sediments of pannonian and pontian ages. the last, 3rd depositional megacycle comprises the pliocene–quaternary sediments of the lonja formation. the analysed lower pontian sandstones belong to the 2nd depositional megacycle, characterised by a relatively uniform alternation of sand/sandstones and silts/ marlstones, in different proportions. 3. quantitative analysis of the pepelana and poljana sandstones there is a general rule concerning the negative correlation between porosity and depth, but only on the condition that large enough vertical intervals are observed. the question is: how large is this depth difference in the central part of bjelovar sag? an increase in depth will usually result in a decrease in porosity, mostly due to compaction. also, compaction is only one of several factors that have an effect in phases of early diagenesis and diagenesis. early diagenesis is characterized by the mechanical influence of compaction as well as chemical effects resulting from water circulation, mineral dissolution (mostly carbonates) and secondary porosity creation. the diagenesis phase includes plastic rock deformation, overpressuring with fracturing and fissure creation. also grain deformation and strong compaction take place, and increased temperatures cause additional cementation. available data on the sandstone members and cores are listed in tables 1 and 2. pepelana sandstones values are collected from 5 wells (7 cored intervals) and poljana sandstones from 4 wells (6 cored intervals). these datasets were the input for statistical correlation (t-test and f-test) analyses. 3.1. correlation analysis and interpretation of depth differences pearson correlation coefficients (r) between all porosity and depth values for each member are calculated. also minimum and maximum depth and porosity values as well as standard deviation values are listed in table 3. it is noticeable that the r-value for each intra-member group (velika ciglena and other locations) selected in the pepelana and poljana sandstones are significantly correlated (this analysis is extended with student’s t-test in subsection 3.3). also, velika ciglena data are positively correlated, which indicated a local deviation from the expected behaviour (see section 3.2). data from other locations are negatively correlated with depth. results published by jüttner et al. (2000), regarding the correlation of porosity and depth show values of porosity–depth correlation of -0.19 at stružec and 0.57 at okoli in the sava depression. they statistically analysed four parameters; φ, horizontal and vertical permeability and depth. although no significance test was performed, the okoli result describes a strong negative correlation between porosity and depth. based on such correlations, compaction was assumed at significant lower depth differences (150 m at okoli field) than it was supposed for equivalent lithostratigraphic members in the central part of bjelovar sag. this is a result of the relatively large depth of these members at okoli field (1850–2000 m). similar analysis was the main goal of this paper, i.e. determination of the range, as precise as possible, where compaction and depth have influence on the decrease in porosity. cores were taken in stratigraphically very different parts of the analysed members, from the youngest part of the pepelana sandstones to the oldest part of the poljana sandstones (figs. 3 and 4). the mean porosity of the cored intervals is mostly very similar despite strati sandstone n mean min max std. dev. r p member dpe 101 823.845 680.30 1052.50 95.8419 φpe 101 24.313 6.80 33.10 6.5837 −0.2631 0.008 dpevc 43 1538.953 1479.25 1583.25 42.5746 φpevc 43 16.951 6.90 25.60 4.0242 0.5468 0.000 dpl 68 1014.750 913.50 1315.50 134.6637 φpl 68 24.921 6.90 33.00 4.3558 −0.4974 0.000 dplvc 27 1787.935 1747.00 1846.00 48.0170 φplvc 27 14.133 6.20 24.60 4.3935 0.4381 0.022 table 3 descriptive statistics for depth and porosity in both sandstone members. legend: pe = pepelana, pl = poljana, pevc = pepelana (velika ciglena), plvc = poljana (velika ciglena), d = depth, φ = porosity. 80 geologia croatica 58/1 graphic position and location (tables 1 and 2) – average is 24.5%, and maximum about 30%. exceptions include data from well vc–1, where the average is 15.7%, and the maximum average was 25%. interestingly, the total mean porosity in both sandstone members is exactly the same at 21.8%. generally, the pepelana and poljana sandstones (eliminating the two extremes) are approximately 550– 900 m deeper in velika ciglena (well vc–1) than elsewhere (tables 1 and 2, figs. 3 and 4). minimum and maximum differences between the top and bottom of the analysed members are: – the top of the pepelana sandstones in the vc–1 well is 356 m deeper than in the rov-1 well, and approximately 971 m below the top in well ša–5; – the base of the pepelana sandstones in vc-1 is 547.9 m deeper than in rov–1 and 895 m (ša–5); – the top of the poljana sandstones in vc-1 is 557.1 m deeper than in rov–1 and 837 m (pav–1); – for the base of the poljana sandstones these figures are 712.2 m (rov–1) and 1006 m (pav–1). it is clear that such depth differences have to be reflected in the compaction rates as well as in porosity decreases. locally, it was described that the mean porosity value was about 10 (absolute) % lower in well vc–1 than elsewhere. these listed differences between the top and bottom of the sandstone members show an approximate range of 400 m as the range when compaction starts to have a measurable influence on porosity values. 3.2. analysis of vertical porosity within and among the single wells the possible decrease in the mean core porosity was also analysed within both an individual member and a single well. it was only possible to perform this for those wells with two or more cores from the same member, e.g. well vc–1 with three cores in the pepelana sandstones, and wells pav–2 and vc–1 with two cores each in the poljana sandstones. all three cores in the pepelana sandstones (well vc–1) showed a simultaneous increase of mean porosity and depth, although the mid points of the shallowest and deepest cored intervals are 100.4 m apart (table 1, well vc–1). an identical result is given for cores taken from the poljana sandstones. in the pav–2 well, the mean porosity in the deeper core is higher by 5%, although the distance between the shallow and deeper cores is 91.75 m. very similar results were obtained for well vc–1, where the porosity is higher by 3.81% in the core that is 95.9 m deeper (table 2). it is obvious that porosity decrease as result of compaction was not observed at all here, i.e. the depth difference of 100 m was not large enough to be significant in this way. in contrast, there is locally higher mean porosity observed in the deeper cores. this is why separate porosity–depth diagrams were constructed for each member (figs. 5 and 6). figures 5 and 6 show simple porosity variation curves. the interval mean porosity values in the analysed cores of pepelana (5 wells, 7 cored intervals) and poljana sandstones (4 wells, 6 cored intervals) are placed on the horizontal axis, while relative depths are placed on the vertical axis. this shows the trend of porosity variations with depth to be compared for both members. it is possible to visually evaluate the behaviour of mean porosity in different cores regarding depth. figures 5 and 6 present similar regularity, i.e. data are grouped in two sets. mean porosities calculated for the cores from šandrovac, galovac–pavljani and rovišće represent the first (shallower), while porosities from velika ciglena represent the second group. the same approach is applied for both the pepelana and poljana sandstones. it is clear that the depth difference of the cores in each group falls within the range of 100–400 m. the variability of porosity in each group is not explained by compaction, but by another mechanism. high lithological variability could be clearly observed in the core descriptions of the analysed fineand medium-grained sandstones. such variability is the result of the very different and occasionally high proportion of silts, marlstones or clays. it is why the unexpected, simultaneous increase of porosity and depth could be explained by a sedimentological mechanism. such a mechanism is also the reason for the variability in porosity within the groups. in contrast, the influence of compaction could only be determined by comparison of velika ciglena with other data from shallower groups, i.e. in the porosity decrease as a result of inter-group variation. such variations could be observed after comparing cores among the groups. depth differences between the deepest core in the first, and the shallowest core in the second group are compared. in the pepelana sandstones the vertical distance of cores in wells rov–1 and vc–1 is 430.9 m (fig. 5). in poljana sandstones this distance (the same wells) is 435.5 m (fig. 6). also, the differences between the shallowest and deepest cores inside the same group are compared. in the first group this distance in the pepelana sandstones amounts to 366.2 m (wells ša–5 and rov–1), while in the poljana sandstones it is 392.75 m (pav–1 and rov– 1). in the second group (velika ciglena) these differences are significantly lower – 100.25 m (pepelana sandstones) and 96 m (poljana sandstones). compaction is not observable from the data within the groups, although the maximum distance between cores is 392.75 m, determined in the first group of pepelana sandstones. however, the compaction effect is recorded by comparing the data from different groups, i.e. comparing data from depth differences of 400– 500 m. 81malvić, velić & peh: qualitative–quantitative analyses of the influence of depth... compiling these results, a minimum depth difference of 400 m is accepted as a limit when compaction will have to take place to influence porosity decrease in the same lithostratigraphic unit. it is clear that the influence of compaction cannot be observed in the data from a single well, because the thicknesses of the particular members do not exceed the value of 400 m. in the pepelana member it varies between 55 m (pav–1) and 314 m (vc–1). in the poljana member this range is from 129 m (pav–1) to 298 m (vc–1). such a result could be very useful regarding the control point values calculation as an input for interpolation. in such a case, the mean porosity value will not depend on the vertical position of the core in a particular member at the same locality. it makes porosity mapping (e.g. malvić & đureković, 2003) in these units easier, because point values are simply represented by the arithmetical mean of interval values, which are not dependent on the stratigraphic position of the cores. 3.3. testing the group differences to compare two sample collections or populations and decide either for, or against their statistical similitude one should perform some specific statistical tests such as, for example, the simple tand f-tests. broadly speaking the t-test is always used for the practical purposes of either: (1) testing hypotheses about the equivalence of two sets of data (equality of means), or (2) establishing the possibility that a given sample could belong to a population having some specific characteristics (davis, 1986). theoretically, in the presented case both types of analysis could have been performed, namely, testing the differences between the porosity of the two groups of sandstones vertically disposed within the same sandstone formation, and searching for the critical values of reduced porosity which may be indicative of a depth difference between these groups having resulted from the process of compaction. however, there are two assumptions that must be justified before the t-test is run, particularly when referring to the former example. the first assumption prevents the violation of normality, the second requires the homogeneity of variance. fig. 5 mean analysed core porosities and depth differences in pepelana sandstones. fig. 6 mean analysed core porosities and depth differences in poljana sandstones. 82 geologia croatica 58/1 it is common when dealing with most geological problems that normal (and lognormal) distributions are the exception rather than the rule, which poses considerable constraints on the statistical treatment of such data (reimann & filzmoser, 2000). the distribution characteristics of porosity are in full accordance with this state of affairs, only that in this particular case their distinctive trait is reflected in a typically negative skewness (see table 4). negatively skewed distributions are fairly rare in natural systems, generally occurring when many of the observations linger at, or near, an upper limit set by some natural process (koch & link, 1980). porosity is expected to attain progressively lower values as the process of compaction develops. accordingly, the porosity in the shallower parts of some sedimentary complexes would show significant departure from normality, while the deeper parts, in contrast, would tend to normality as the increasing number of observations cluster symmetrically around some lower central value. this is easily seen in the present case where the porosity ratio in the deeper, velika ciglena horizons, or series, in both the pepelana and poljana sandstone members either approaches (pepelana–vc), or actually assumes (poljana–vc) a normal distribution in respect to the shallower horizons (table 4). however, in testing the variances and means of samples taken in different geological domains, departure from normality is not usually seen as a problem if the data suite is rather large, with the number of cases n>30 (davis, 1986). the second assumption though, is critical, and requires that the equality of variances of the two comparison groups is guaranteed before the additional t-test is performed. if variances, ordinarily checked by the simple f-test, are not equal there is no sense in testing the equality of means because the difference between the two groups is already obvious. to begin with, in this particular case the hypothesis that the two sandstone horizons from the pepelana and poljana members, namely, shallower and deeper, belong to the same population is tested. an alternative hypothesis is that they are of a different origin. the premises are the same for the f-test examining the equality of variances as for the t-test checking the equality of means. thus: (1) h0:σ1 = σ2 h1:σ1 ≠ σ2, and (2) h0:µ1 = µ2 h1:µ1 ≠ µ2 the problem tested by the hypothesis and its alternative is simple: is the difference between the group means significant at the selected level (usually α=0.05). if the terms in the first set of equations are met and variances between the groups do not differ significantly, then the additional test for equality of means can be safely applied. the results of the test for pepelana and poljana sandstones are given in table 5. it is clear from the calculated f-statistics that for the first pair of variates (ϕpepelana /ϕpepelana–vc) the null hypothesis is rejected, meaning that there is ample statistical evidence to suggest that the porosity ratio in the shallower and deeper horizons of the pepelana sandstones are significantly different. obviously, these two series do not represent parts of the same population (h1: σ1 ≠ σ2). in contrast, the second pair of variates (poljana/ poljana–vc) behaves in a quite different manner, as the f-test does not result in rejection of the hypothesis about the equality of variance (h1:σ1 = σ2). however, using the additional t-test, the hypothesis of equality of their means is nevertheless rejected (h1:µ1 ≠ µ2), which, again, places the deeper region of the poljana sandstones (poljana–vc) in different circumstances, with respect to its overlying shallower counterpart (table 5). thus, in the final analysis, the hypothesis about the deeper and shallower sandstone series in either area (pepelana and poljana) belonging to the same, homogeneous member, at least as regards their porosity, is rejected by both statistical tests. the second method of utilizing the t-test can be safely applied after the previous analysis had established the clear statistical difference between the compared groups. the problem emerging in this instance is to find the φ n skewness kurtosis k–s s–w (p) pepelana 101 -0.62 -0.46 0.13 <0.000* pepelana–vc 43 0.22 0.29 0.24 <0.001* poljana 68 -1.32 3.87 0.13 <0.000* poljana–vc 27 -0.13 0.10 0.14 <0.138* table 4 distribution characteristics of porosity. legend: k–s = kolmogorov–smirnov test; s–w = shapiro– wilk’s test; * = normal distribution. φ f-value t-value df p pepelana/pepelana–vc 2.68* 142 0.000 poljana/poljana–vc 1.02* 10.862* 93 0.000 table 5 fand t-statistics for two pairs of variates (φ). legend: * = fand t-values exceeding critical. 83malvić, velić & peh: qualitative–quantitative analyses of the influence of depth... much lower porosity represented by the mean value of 16.951%. if the natural law of the decrease of porosity with depth is applied on this occasion, one would expect further reduction of porosity with depth which would place the velika ciglena member in some intermediate position. however, due to the variable proportions of clay in different parts of the sandstones, porosity actually can become higher with depth (positive correlation in table 3). this phenomenon requires a different approach applying an inverse procedure: it would be reasonable to expect the compactness being still greater in a limited region immediately above the porosity ratios represented by the mean for the deeper velika ciglena population. thus a lower porosity can be proposed for a somewhat shallower hypothetical sample for which the computed t-value would be critical. in this case the hypothesis and its alternative only change their signs with respect to the former case. the computed critical t-value of 1.988 is found for the respective porosity ratio of 15.731% (table 6), and it can be deemed to be the representative value for maximum compaction in the pepelana sandstones. the range between the area with significantly observable compaction and maximum compaction would thus be the range between the two critical margins, namely 23.022% and 15.731%, which equals 7.291% for the pepelana sandstones. to recalculate these values into depths is a simple task using the regression lines between porosity and depth. in the case of pepelana the regression lines are: critical value of porosity for the depth where the process of compaction has significantly changed the physical characteristics of the shallower sandstone series. in other words, as seen in the light of negative correlation between depth and porosity, one must propose a porosity ratio that would not belong to the parent population (the shallower sandstone member), but must be significantly lower. this value can be tested by the standard onetailed t-test (α=0.05), which is appropriate on this occasion because only one critical region of the population is examined – that with decreasing porosity (increasing depth). in the shallower part of the pepelana sandstones the mean value of porosity ratio equals 24.313% (see table 3), but to compute the critical t-value that discriminates the two sandstone series, a hypothesis and its alternative must be tested which state that: h0 :µ = µ0 and h1:µ < µ0 which is accepted for: ≤ tc or: µ0 ≥ where the symbols are as follows: x– = mean porosity of the parent population (shallower series), σ = standard deviation of the parent population, and n = number of observations (table 3); tc = critical t-value; µ0 = hypothetical mean of a deeper population. as the procedure of finding the critical value is tentative, by consecutive decreasing of the proposed porosity ratios during the test one can eventually find a number for which the computed t-value is critical. in practice, it means that the hypothetical sandstone series with the porosity ratio thus computed (representing its mean) do not belong to the parent population (the shallower pepelana sandstones), but neither to the deeper velika ciglena member distinguished by much lower values. a decision can be made that, according to the ttest, the proposed porosity ratio on the verge of the critical region represents those samples in the upper part of the pepelana sandstones where compaction becomes significantly observable. the critical t-value and critical porosity found by the t-test are thus 23.022% and 1.971, respectively (table 6). a similar procedure was carried out for the deeper member of the pepelana sandstones (velika ciglena) where the process of compaction has resulted in a φ t-critical df p φ-critical depth range pepelana 1.971 100 0.05 23.022 893.92 pepelana–vc 1.988 42 0.05 15.731 1515.31 621.39 poljana 1.977 67 0.05 23.877 1078.94 poljana–vc 2.006 26 0.05 12.437 1745.93 666.99 table 6 fand t-statistics within members. the recalculated range of compaction thus spans between 893.92 m and 1515.31 m, or 621.39 m in total (table 6). an identical procedure is repeated for the poljana sandstones. from table 6 it is clear that the range of compaction is considerably wider in the light of porosity, from 23.877% to 12.437% (11.44% in total), due to the lower values in the deeper member of the poljana sandstones (velika ciglena). however, after recalculating porosity into corresponding depth using the regression lines for these sandstones: 84 geologia croatica 58/1 the range appears only slightly wider, spanning between 1078.94 m and 1745.93 m, which is 666.99 m. the procedure described in this subsection could be considered as a more precise extension of the determination of the compaction depth difference given in subsection 3.2. the minimal depth difference of 400 m estimated graphically (figs. 5 and 6) is numerically recalculated at 621.4 m (pepelana) and 667.0 m (poljana). one must be aware, though, that porosity values (as well as depth) with two or three decimals are statistically valid and appear as a result of statistical computations, which is the only reason for being written in this manner throughout the text. in the last analysis, such precisely calculated numbers are not geologically meaningful and can be soundly reduced to one decimal (ϕ ), or given to a round figure (depth). 4. conclusions a detailed study of porosity and depth in the sandstone members of the kloštar-ivanić formation (lower pontian) was performed using the data obtained from core analysis. this is supported by other available data gathered from several well files from the sedimentary environment, together with granulometric analysis and electric log interpretations. generally, the data were treated in two ways. firstly, the diagrammatic representation of both investigated variables was amply utilized in analysis – depth differences from the cores and porosity–depth plots were drawn for both sandstone members. secondly, a detail statistical analysis of porosity was carried out separately for two groups, or series, within the same sandstone member – shallower and deeper (the latter known as velika ciglena group). comparison of the results from the two approaches (graphical and statistical) allow the following conclusions to be drawn: – porosity values in these lower pontian sandstones are negatively correlated with depth in the shallower series, but, in contrast, a good positive correlation is found between these variables in the deeper, velika ciglena group. – the qualitative aspect is expressed through lithological variability of the sandstones, as result of their very different and occasionally high proportion of silts, marlstones or clays. this is why the porosity within a particular group varies and even increases with depth. – dependence between porosity and depth is established in two ways: (a) graphically, with more than 400 m of depth difference at the same location, and (b) by the use of statistical tests which set the limits for the influence of compaction at a minimum of 621 m in the pepelana, and 667 m of depth difference in the poljana sandstones. – there is no single location (well), where the thickness of the pepelana and poljana sandstones exceeds 400 m. because of the latter, it is appropriate to calculate the porosity value as an arithmetic mean of interval core porosities at a particular location regardless of the influence of compaction. – the mean porosity value is not dependent on the vertical position of the core in a particular member at a given locality. this allows the calculation of simple arithmetic means to be used as possible mapping and, consequently, easier porosity interpolation. – analysed sandstones are located more than 400 m deeper in the velika ciglena area than in other wells. a compaction-related porosity decrease is clearly reflected only in the case where the porosity values of velika ciglena are compared with other locations. acknowledgements this research was performed as part of the ministry of science project no. 0195035 at the faculty of mining, geology and petroleum engineering (institute for geology and geological engineering) and in the geological reservoir development department, which is part of ina-naftaplin, development division. we thank all the responsible persons in charge at ina-naftaplin for giving permission to use data from company professional documentation. last but not least, the authors greatly appreciate the careful and fair review of dr. slavka pfaff, dr. wolfgang nachtmann and dr. ubul fügedi. their very useful suggestions and comments helped us to improve our work and more clearly present the results. 5. references buryakovskiy, l.a., djevanshir, r.d. & chilingarian, g.v. (1991): mathematical simulation of sediment compaction.– journal of petroleum science and engineering, 5/2, 151–161. davis, j.c. (1986): statistics and data analysis in geology.– 2nd edition. john wiley and sons, new york, 646 p. jüttner, i., saftić, b. & velić, j. (2000): distribution of porosity and permeability within the pontian sandstones in the western part of sava depression in relation to their stratigraphic architecture and palaeotectonic relations.– nafta, special issue dedicated to the 2nd international symposium on petroleum geology, april 22–24, 1999, zagreb. koch, g.s & link, r.f. (1980): statistical analysis of geological data.– dover publications inc., new york, 438 p. malvić, t. (2003a): naftnogeološki odnosi i vjerojatnost pronalaska novih zaliha ugljikovodika u bjelovarskoj uleknini [oil-geological relations and probability of discovering new hydrocarbon reserves in the bjelovar sag – in croatian with english abstract].– unpubl. phd thesis, university of zagreb, 123 p. 85malvić, velić & peh: qualitative–quantitative analyses of the influence of depth... malvić, t. (2003b): one-dimensional variogram and statistical analysis in reservoir units of the bjelovar sag, croatia.– nafta, 54/7–8, 267–274, zagreb. malvić, t. & đureković, m. (2003): application of the methods: inverse distance weighting, ordinary kriging and collocated cokriging in the porosity evaluation, and comparison of results on the beničanci and stari gradac fields in croatia.– nafta, 54/9, 331–340, zagreb. reed, j.s., eriksson, k.a. & kowalewski, m. (2005): climatic, depositional and burial controls on diagenesis of appalachian carboniferous sandstones: qualitative and quantitative methods.– sedimentary geology, 176/3–4, 225–246. reimann, c. & filzmoser, p. (2000): normal and lognormal distribution in geochemistry: death of a myth. consequences for the statistical treatment of geochemical and environmental data.– environmental geology, 39/9, 1001–1014. royden, l.h. (1988): late cenozoic tectonics of the pannonian basin system.– in: royden, l.h. & horváth, f. (eds.): the pannonian basin. am. assoc. petrol. geol. memoir, 45, 27–48, tulsa. rögl, f. (1996): stratigraphic correlation of the paratethys oligocene and miocene.– mitteilungen ges. geol. bergbaustud. österreich, 41, 65–73, wien. rögl, f. (1998): palaeographic consideration for mediterranean and paratethys seaways (oligocene to miocene).– ann. naturhist. mus. wien, 99a, 279–310, wien. saftić, b., peh, z., velić, j. & jüttner, i. (2001): interdependence of petrophysical properties and depth: some implications of multivariate solution on distinction between the lower pontian hydrocarbon-bearing sandstone units in the western part of the sava depression.– geol. croat., 54/2, 259–277. šimon, j. (1980): prilog stratigrafiji u taložnom sustavu pješčanih rezervoara sava-grupe naslaga mlađeg tercijara u panonskom bazenu sjeverne hrvatske [contribution to the stratigraphy of sandstone reservoirs depositional system of the younger tertiary sava-group deposits in the pannonian basin of northern croatia – in croatian].– unpubl. phd thesis, university of zagreb, 66 p. tišljar, j. (1994): sedimentne stijene [sedimentary rocks – in croatian].– školska knjiga, zagreb, 416 p. velić, j., weisser, m., saftić, b., vrbanac, b. & ivković, ž. (2002): petroleum-geological characteristics and exploration level of the three neogene depositional megacycles in the croatian part of the pannonian basin.– nafta, 53/6–7, 239–249, zagreb. vrbanac, b. (1996): paleostrukturne i sedimentološke analize gornjopanonskih naslaga formacije ivanić grad u savskoj depresiji [palaeostructural and sedimentological analysis of the upper pannonian deposits of the ivanić grad formation in the sava depression – in croatian].– unpubl. phd thesis, university of zagreb, 303 p. manuscript received march 2, 2004. revised manuscript accepted april 15, 2005. 86 geologia croatica 58/1 gc-60-2.indb 1. introduction one of the most important palaeogeographic changes in the geological evolution of the central paratethys basin occurs at the sarmatian/pannonian boundary. during the sarmatian (s. str.), the central paratethys was part of an epicontinental marine water mass (e.g. piller & harzhauser, 2005; steininger & rögl, 1985) and water exchange was suggested to have takpalaeomagnetic results from the sarmatian/pannonian boundary in north-eastern croatia (vranović section, našice quarry) iuliana vasiliev1, koraljka bakrač2, marijan kovačić3, hayfaa abdul aziz1 and wout krijgsman1 en place with the open seas and with the eastern paratethys basins (e.g. magyar et al., 1999). the straits between central paratethys and the global seas caused a severe separation of water bodies resulting in aberrant isotope signatures, high salinities and elevated alkalinity (e.g. piller & harzhauser, 2005). the sarmatian/pannonian boundary interval is marked by a major regression, which isolated the central paratethys from the sea, transforming it into the large, long-lived, brackish water body of lake pannon (e.g. piller & harzhauser, 2005). the cause of this regression is still highly debated, and the main hypotheses are (1) eustatic sea level lowering (vakarcs et al., 1994; harzhauser & piller, 2004), (2) tectonic events in the carpathians and dinarides (e.g. sandulescu, 1988), and (3) intraplate stress (horváth & cloeting, 1996). without an accurate time frame for this event, it is at present difficult to solve this controversy and to understand the underlying mechanisms. the age of the sarmatian/pannonian boundary is at present largely based on observation of the fossil remains of the three-toed equid hippotherium in the lower part of the pannonian sequences (e.g. bernor et al., 1988; rögl & daxner-höck, 1996). correlation with the dominantly reversed polarity palaeomagnetic data from the hippotherium-bearing sediments of kastellios hill on crete (sen et al., 1986) resulted in an approximate age of 11.5–11.6 ma for the base of the pannonian (steininger et al., 1990, 1996). later, however, detailed palaeomagnetic studies indicated that hippotherium only commonly appeared in the lower part of chron c5n at an age between 10.8 and 10.6 ma, in asia (barry et al., 1982, 1985; kappelman et al., 1996; woodburne & swisher, 1995) as well as in spain (garcés et al., 1996, 1997, 2003; krijgsman et al., 1996). consequently, it was shown that the kastellios hill magnetostratigraphy correlates best to chron c4ar at an age between 10.7 and 9.1 ma (garcés et al., 1996). to date, no palaeomagnetic data have been reported from the pannonian hippotherium sites, probably because of outcrops being unsuitable for magnetostratigraphy. radiometric ages do exist from the early hippotherium sites at höwenegg in germany (10.8±0.3 ma; baranyi et al., 1976) and the vienna basin (11.1±0.5 ma; bernor et al., 1993a, b). hence, there seems to be a general agreement on geologia croatica 60/2 151–163 9 figs. zagreb 2007 key words: palaeomagnetism, palynology, sarmatian, pannonian, central paratethys, croatia. 1 palaeomagnetic laboratory ‘fort hoofddijk’, utrecht university, budapestlaan 17, nl-3584 cd utrecht, the netherlands; e-mail: vasiliev@geo.uu.nl 2 croatian geological survey, sachsova 2, hr-10000 zagreb, croatia. 3 department of geology, faculty of science, university of zagreb, horvatovac bb, hr-10000 zagreb, croatia. abstract the sarmatian/pannonian boundary in the central paratethys basin is marked by a major regressive event, which isolated the basin from the open sea and resulted in a palaeoenvironmental change from restricted marine to brackish water ecosystems. the exact age of this environmental change is still ambiguous since direct age control on the boundary interval is lacking, mainly due to the scarcity of suitable sections. the vranović section in the našice quarry in croatia, however, is relatively long and continuously exposed. a detailed sedimentological and biostratigraphic study indicates that it contains the sarmatian/pannonian boundary and that it reflects the same palaeoenvironmental trend as other paratethyan sequences. here, we present palaeomagnetic and rock magnetic results from the vranović section, based on 183 sampled levels distributed along 55 m of cyclically bedded limestones and marls. rock magnetic data indicate the presence of maghemite or haematite in the sarmatian deposits and low contents of magnetite in the pannonian rocks. thermal demagnetization results indicate dominantly normal polarities, and the mean direction closely coincides with the present-day field direction at našice. we conclude that magnetostratigraphic age control cannot be derived for the vranović section because of a dominant secondary (post-tilt) magnetization. consequently, a firm numerical age based on magnetostratigraphy cannot be assigned to sarmatian/pannonian boundary events from this section. 152 geologia croatica 60/2 the so-called hippotherium datum, occurring at an age younger than 11.1 ma (e.g. agustí & moyà-solà, 1991), but, remarkably, the age of the sarmatian/pannonian boundary was never revised accordingly. the relative sea level drop at the sarmatian/pannonian boundary caused large areas in the central part of the central paratethys basin to dry up, and only small, scattered patches of the originally thin sarmatian deposits escaped complete erosion (e.g. magyar et al., 1999). it is therefore difficult to find exposed sections of uninterrupted sedimentation through the marine/ lacustrine boundary. in the southern part of the central paratethys basin, a conformable transition from the sarmatian to the pannonian deposits has been found much more frequently than an unconformable one. a relatively long and excellently exposed section, comprising the sarmatian/pannonian boundary, exists in north-eastern croatia in a quarry near našice (fig. 1). the vranović section expresses a noticeable sedimentary cyclicity of alternating limestones and marls (fig. 2). the regularity of this cyclicity suggests a relationship with astronomically induced changes in palaeoclimate (milankovitch forcing). the section has previously been studied for sedimentological and biostratigraphic purposes which resulted in detailed palaeoenvironmental and lithostratigraphic interpretations (pavelić et al., 2003; kovačič, 2004; bakrač, 2005; kovačić & grizelj, 2006). here, we present palaeomagnetic results, including a detailed rock magnetic characterization, of this exceptional sarmatian/pannonian boundary section in the central paratethys, with the aim to develop a reliable chronostratigraphic framework for the entire interval using integrated bio-cyclo-magnetostratigraphic techniques. 2. geological setting the pannonian basin is presently surrounded by the alps, carpathians and dinarides, and belongs palaeogeographically to central paratethys (fig. 1). the basin formed in the early miocene, as a consequence of continental collision and subduction of the european plate under the apulian plate (tari et al., 1992; horfig. 1 location of the studied area: (a) pannonian basin; (b) study area; (c) geological sketch map after korolija & jamičić, 1988. legend: 1) pre-miocene; 2) badenian; 3) sarmatian; 4) lower pannonian; 5) upper pannonian – plio–quaternary; 6) pleistocene; 7) holocene; 8) normal stratigraphic boundary; 9) transgressive boundary; 10) faults; 11) location of the sampled section. a b c 153vasiliev et al.: palaeomagnetic results from the sarmatian/pannonian boundary... váth & cloetingh, 1996; kovác et al., 1998; royden, 1988). miocene deposits of the southern part of the pannonian basin, unconformably overlie a strongly tectonized palaeozoic–mesozoic–palaeogene basement of magmatic, metamorphic and sedimentary rocks. from the early to the middle miocene (middle badenian), in the syn-rift phase of basin formation, deposition of clastic and carbonate sediments was accompanied by strong tectonic and volcanic activity. the post-rift phase of basin formation (upper badenian to recent) is characterized by subsidence due to lithospheric cooling, with occasional inversions of the basin generated by intraplate stress that affected the entire pannonian basin (horváth & cloetingh, 1996). during the late sarmatian, tectonic compaction occurred in the southern part of the pannonian basin. contemporaneously, the connection between the pannonian basin and the mediterranean was closing, and lake pannon formed as a separate depositional system with low salinity waters (steininger et al., 1988; rögl, 1996). however, recent studies indicate isotope trends suggesting a simple system of an alkaline lake with steadily declining salinity (harzhauser & piller, 2007; harzhauser et al., 2007). at the beginning of the pannonian, under conditions of low tectonic activity, limestones and marls were mostly deposited. lake-level rise during the pannonian caused flooding of previously emerged regions. progradation of deltaic clastic systems, shallowing and finally infilling of the basin during pontian times was probably caused by deceleration of basin subsidence. during mio–pliocene times, and more intensively in the quaternary, another compressive phase took place in the pannonian basin, uplifting and exposing its southern margin in croatia (jamičić, 1995; horváth & cloetingh, 1996; prelogović et al., 1998; márton et al., 2002). 3. našice quarry – vranović section the našice quarry is located on the northern slopes of mt. krndija, which belongs to the southern part of the pannonian basin (figs. 1 and 2). sediments of the croatian margin are characterized by widely different lithologies, starting with upper badenian (~14 ma) carbonates and ending with pontian (~5 ma) siliciclastics. during this period, the depositional environment changed from fully marine, to reduced marine and finally brackish (pavelić et al., 2003). the vranović section is located in the northern part of the quarry. it measures 55 metres in thickness and comprises upper sarmatian and pannonian sediments as evidenced by the occurrence of specific palynomorphs (bakrač, 2005). the sedimentary succession is divided into three informal lithostratigraphic units: (1) ‘kasonja formation’, (2) ‘croatica formation’, and (3) ‘pavlovci formation’ (figs. 2 and 4). the ‘kasonja formation’ is only exposed in the lowermost 4 metres of the section, and represents the sarmatian part of the sequence (fig. 2 and 4; up to v6). it consists of horizontally laminated marls. the marls are well bedded, with bed thickness varying between 10 and 70 cm (fig. 4). horizontal lamination is generally varve-like suggesting seasonal changes in sedimentation. in some places the marls are massive or contain intercalations of clays and limestones. the marls were deposited from suspension in a relatively deep, calm sedimentary environment. fossil associations indicate a transition from a reduced marine to brackish water environment, which is a similar trend to other sarmatian–pannonian sequences (pavelić et al., 2003). palynomorph assemblages consist of marine dinocysts that are tolerant to decreased salinity: hystrichosphaeropsis obscura, polysphaeridium zoharyi, lingulodinium machaerophorum (fig. 3a), and brackish-water dinocysts spiniferites bentori budajenoensis (bakrač, ������������������������������ fig. 2 photograph of the lower part (sarmatian–early pannonian) of the vranović section that contains clear sedimentary cycles. the carbonate-rich layers can be observed. the average thickness of a basic limestone–marl cycle is 0.7 m. 154 geologia croatica 60/2 2005). this assemblage is also typical of the late sarmatian deposits in hungary (sütő-szentai, 1988). the ‘croatica formation’ consists of horizontally bedded, marly limestones, intercalated with massive marls, and represents the lowest pannonian part of the succession (fig. 2). bed thickness ranges between 10 and 30 cm (fig. 4) and the fossil association in the lower part indicates an earliest pannonian age (‘croatica beds’ – pavelić et al., 2003; kovačić, 2004; kovačić & grizelj, 2006). the sediments were deposited from suspension under oscillating warmer and cooler temperatures that generated high carbonate production. deposition of the carbonates is thought to have occurred in a littoral zone in brackish–lacustrine environments, while the marly intercalations indicate water-level oscillations that temporarily formed deeper lake levels. during that time, salinity was so low that the environment became oligohaline, and locally even fresh. such environmental conditions enabled the expansion of endemic species. ecological conditions were unfavourable for dinoflagellates, which is evidenced by the absence of dinocysts in these sediments. consequently, prasinophyte algae mecsekia ultima, mecsekia spinosa and mecsekia incrassata dominate the phytoplankton assemblages (bakrač, 2005). the ‘pavlovci formation’ is predominantly composed of massive marls of early pannonian age (‘banatica beds’), and represents about 50% of the succession (pavelić et al., 2003; kovačić, 2004) (fig. 4). the marls form units 0.3–6.0 m thick. they are bioturbated and yellowish to light grey in colour. the calcite content is high, reaching up to 77%. the marls were deposited in a deeper zone of the brackish lake than the marly limestones of the ‘croatica formation’. the lake bottom was oxygenated, enabling colonization by benthic organisms that produced bioturbation. the dinocyst assemblage of spiniferites bentori pannonicus (fig. 3b), spiniferites bentori granulatus, and impagidinium spongianum characterizes these deposits, and can be correlated with the assemblage of spiniferites bentori pannonicus zone in hungary (sütő-szentai, 1988). within the succeeding deposits, spiniferites bentori pannonicus and spiniferites bentori oblongus dominate the palynomorph assemblages. nematosphaeropsis sp. and membranous forms of spiniferites bentori indicate water-level rise and a distal environment. this assemblage is similar to that of the spiniferites bentori oblongus zone from hungary (sütő-szentai, 1988). 4. palaeomagnetic results 4.1. methods in the field, at least two standard palaeomagnetic cores were drilled at 183 individual sample levels with an electrical drill and a generator as power supply. in the laboratory, rock magnetic experiments were performed to characterize the carrier(s) of the magnetization. thermomagnetic runs in air were measured with a modified horizontal translation type curie balance with a sensitivity of approximately 5×10-9 am2 (mullender et al., 1993). a few milligrams of bulk sample were put into a quartz glass sample holder and were held in place by quartz wool. the measurements were carried out up to 700°c for samples for diverse lithologies. an alternating gradient magnetometer (micromag model 2900 a b fig. 3 (a) the sarmatian dinocyst lingulodinium machaerophorum (deflandre & cookson, 1955) wall, 1967; (b) the pannonian dinocyst spiniferites bentorii pannonicus sütő-szentai, 1986. 155vasiliev et al.: palaeomagnetic results from the sarmatian/pannonian boundary... � 20°c 20°c fig. 4 low-field magnetic susceptibility, nrm intensity, lithological column, and palaeomagnetic declination/inclination record for the vranović section. the initial nrm intensity correlates with (low) χin for the samples collected above 25.5 m, which is highlighted with light-grey shading; no correlation is observed for the samples below 25.5 m (darker-grey patch). light-grey beds in the lithological column correspond to the indurated limestones; darker-grey beds represent marls; the very dark shadings are organic rich layers (close to a sapropel type). on the right-hand side of the lithological column is an environmental interpretation, lithostratigraphy and the stages identified in the section (according to pavelić et al., 2003). in the declination–inclination record, the solid symbols represent directions obtained from zijderveld diagrams with the maximum angle deviation mad<15º and with coherent demagnetisation trajectories; the open symbols represent the directions obtained from zijderveld diagrams with mad>15º and with noisy demagnetisation diagrams, also associated with the lowest susceptibility and nrm-intensities. 156 geologia croatica 60/2 – princeton measurements corporation, noise level 2×10-9 am2) was used at room temperature to make the following measurements: (1) hysteresis, (2) isothermal remanent magnetisation (irm) acquisition, and (3) back-field curves. the sample mass ranged from ~0.2 to ~0.5 grams. the hysteresis loops of selected lithologies were recorded to determine the saturation magnetisation (ms), remnant saturation magnetisation (mrs) and coercive force (bc). the values were read after paramagnetic slope correction and on a mass-specific basis. because of the partial saturation of the pole shoes, the response of the micromag model 2900 is not linear above 1.6 t. therefore, we only report the values for a maximum field of 1.6 t. back-field curves allow determination of the coercivity of remnance (bcr) after application of the maximum positive field. irm acquisition curves, containing 300 data points, were noisy and contained little useful information. stepwise thermal demagnetisation has been applied to one sample from each stratigraphic level to determine the palaeomagnetic directions of the nrm. demagnetisation was performed with temperature increments of 5–30°c up to a maximum temperature of 380°c. the samples were heated and cooled in a magnetically shielded, laboratory-built furnace with a residual field less than 10 nt. after each step, the bulk susceptibility was measured on a kly–2 susceptometer (agico, brno, noise level 4×10-8 si) in order to check for possible mineralogical changes during thermal treatment. the natural remnant magnetization (nrm) was measured on a horizontal 2g enterprises dc squid magnetometer (noise level 3×10–12 am2). 4.2. rock magnetism several rock-magnetic experiments were carried out on unheated bulk rock samples to determine in which magnetic mineral(s) the remnance is residing and how it was acquired. thermomagnetic runs show that the initial total magnetisation is low in all measured samples (fig. 5). all hysteresis loops are affected by noise, but the general shape can still be distinguished (fig. 6). the hysteresis loops are generally narrow-waisted (fig. 6a– c), which is typical of multi-domain magnetic behavfig. 5 representative thermomagnetic runs for the analyzed samples. heating is represented by a grey line and cooling by a black line. data in (c) and (d) show major alteration after heating above 400ºc most probably as the effect of the pyrite transformation to magnetite. the drawings do not show the entire heating curve because the out-of-scale trend would limit viewing of the shape of the heat–cool cycle. below the samples codes the stratigraphic level and the stages are indicated. ba c d 157vasiliev et al.: palaeomagnetic results from the sarmatian/pannonian boundary... iour (dunlop & özdemir, 1997). samples from the sarmatian ‘kasonja formation’ reveal hysteresis loops that are not closed in fields of 300 mt, indicating the presence of a high coercivity mineral. the high value of bc = 458.1 mt (fig. 6a) points to the presence of a high coercivity mineral like maghemite, goethite or haematite (usually formed as a result of alteration). in the thermomagnetic runs from the ‘kasonja formation’ and the lowest part of the pannonian ‘croatica formation’, only the paramagnetic matrix contribution was detectable (fig. 5a, b) and the data suggest the existence of very low contents of magnetite. the hysteresis loops of the middle and upper parts of the ‘croatica formation’ indicate the presence of a low coercivity mineral with low values of bc (fig. 6b, c), which most likely represents multi domain magnetite. in the upper part of the section (‘pavlovci formation’), a thermally induced pyrite to magnetite transformation occurs (fig. 5c, d). the presence of pyrite was already presumed because macroscopic pyrite crystals could be distinguished in the upper part of the vranović section. 4.3. thermal demagnetisation nrm intensities are generally low in the basal part of the section, with maximum values of 0.53 mam-1, but they are even lower in the upper part, with a maximum value of 0.14 mam-1. the initial (low) nrm intensity correlates with the (low) initial susceptibility χin and a significant change to lower values is observed above 25.5 m in the section (see fig. 4). stepwise thermal demagnetisation diagrams (fig. 7) and the normalized intensity versus temperature curves (fig. 8) indicates that one remnance component is commonly removed at the relatively low temperatures of 100–160°c. this indicates the presence of either a large laboratoryinduced viscous remnant magnetisation (vrm) or a (sub)recent secondary chemical remnant magnetisation (crm). the random character of this component suggests a laboratory-induced remnance. approximately 80% of the samples from the lower part of the section retained a magnetisation above 160°c, and only 13% of the samples do so from the upper part of the section (fig. 8). after removal of the 160ºc component the intensities decrease to less than 20% of the initial fig. 6 hysteresis loops for characteristic samples measured for -2t≤b≤2t. the figures show the result up to ±500 mt (the important part of the loop) with applied paramagnetic contribution and mass correction. below the sample codes the stratigraphic levels and the stages are also indicated. ba c d 158 geologia croatica 60/2 nrm at 250–320ºc (fig. 7), generally approaching the accuracy level of the magnetometer. demagnetisation at higher temperatures yields inconsistent results and only directional scatter is obtained. directions of the nrm components were determined with principal component analysis (kirschvink, 1980) using at least four temperature steps for each component, from steps higher than 180ºc and always including the origin. all directions with a mean angle deviation (mad) >15º were rejected. the remaining dataset is presented in a declination–inclination plot (fig. 4). the lower part of the vranović section has mainly normal polarities and few reliable, consistent results can be obtained from the upper part of the section. only two levels at 21.25 and 22.15 m show clear indications of reversed polarity (fig. 4, 7). in these cases, a small viscous and randomly oriented component is removed at 100ºc, and a relatively large secondary – it has approximately a present-day field direction before applying of the bedding tilt correction – component at 200–210ºc (fig. 7d). the nrm is removed at 380ºc. when palaeomagnetic data from sedimentary sequences reveal dominantly normal polarities, it is crucial to investigate if these normal directions could result from a present-day field overprint. in the vranović section, the bedding tilt/strike of the sedimentary strata is fig. 7 representative thermal demagnetisation vector diagrams of some selected samples. solid (open) circles denote projection on the horizontal (vertical) plane and the attached numbers indicate temperatures in ºc. stratigraphic levels are written below the sample codes (in capital letters); lithologies are in the lower left-hand corner and next to them are the stages for the different rocks. ba dc fe g 159vasiliev et al.: palaeomagnetic results from the sarmatian/pannonian boundary... approximately 65°/15° dipping se, which is helpful for distinguishing primary from secondary components. the normal polarity directions that passed the mad selection criterion scatter around the geocentric axial dipole field direction for the present latitude of the section when no bedding tilt correction is applied (fig. 9a). after using the statistical cut-off (vandamme, 1994) to this dataset, the calculated mean direction is: declination = 354.5°, and inclination = 62.9°. this is close to the expected present-day field inclination (63.8°) for the latitude of našice (λ = 45.5º). this strongly suggests that the normal polarity directions are of (sub)recent origin, and most likely related to the present-day earth’s magnetic field. in this case, we would also not expect any inclination error related to compaction of the sediment. applying the e/i correction method for inclination error (tauxe & kent, 2004) on our normal polarity dataset, we confirm that the palaeomagnetic directions are not flattened (fig. 9c). the e/i corrected mean inclination of i** = 63.7° is even closer to the expected inclination of 63.8° at našice. although all of this evidence strongly points to a secondary overprint for the normal polarities at vranović, we also investigated the possibility that these directions could have been of primary (pre-tilt) origin. hence, we also calculated the mean of the individual directions after applying a bedding tilt correction (fig. 9). the result, after using the vandamme (1994) cut-off, suggests a mean palaeomagnetic direction with declination = 15.9° and inclination = 76.5°. if true, this implies that the southern margin of the central paratethys was located at a palaeolatitude of λ = 64.4°n (i.e. somewhere in central scandinavia) during the sarmatian/pannonian boundary interval. this clearly demonstrates that the remnance in the vranović section is of secondary origin, which clearly postdates the tectonic tilting of the section. 5. discussion and conclusions detailed sedimentological and palynological studies of the vranović section at našice demonstrates that it comprises the sarmatian/pannonian boundary interval, which is characterized by a major palaeoenvironmental change from reduced marine to brackish water conditions. sarmatian palynomorph assemblages consist of marine dinocysts that are tolerant to decreased salinity and brackish water. in the earliest pannonian, prasinophyte algae dominate the phytoplankton assemblages, and ecological conditions had become unfavourable for dinoflagellates. higher in the sequence, the dinocyst assemblage indicates oxygenated environments and an increase in the water level. the observed biostratigraphic and palaeoenvironmental trend is similar to that observed in hungary (sütő-szentai, 1988), which suggests that it is typical for the entire central paratethys basin. rock magnetic data from the vranović section indicates that the initial magnetization is weak and characterized by multi-domain magnetic behaviour. hysteresis loops and thermomagnetic runs indicate the presence of a high coercivity mineral like maghemite, goethite or haematite in the sarmatian deposits, while the pannonian rocks are typified by low contents of multidomain magnetite. thermal demagnetization reveals a remnant magnetisation component that shows dominantly normal polarities and that has, before bedding tilt correction, a mean direction closely coinciding with the expected present-day geocentric axial dipole field directions at našice. this indicates that the remnance of the vranović samples is of secondary origin and that no magnetostratigraphic age control on the sarmatian/pannonian boundary could be derived from our samples. nevertheless, two stratigraphic levels contain evidence for reversed polarities. fig. 8 normalized intensity versus temperature for selected samples. symbol 1 indicates samples with intensities that drop below 40% after heating at 100ºc; symbol 2 indicates samples with intensity decreasing in two steps, the first at 160ºc and the second at 220ºc; symbol 3 indicates samples with intensity dropping suddenly when heating to 220ºc; symbol 4 indicates (a few samples) with intensity decreasing rapidly after heating at 270ºc. 160 geologia croatica 60/2 a consequence of this study is that the sarmatian/ pannonian boundary remains undated by direct magnetostratigraphic or radiometric techniques. nevertheless, we conclude that it is necessary to re-evaluate the age of 11.6–11.5 ma for the sarmatian/pannonian boundary that figures in the commonly used geological time scales of central paratethys (steininger et al., 1990, 1996). this age is mainly the result of multiple cross correlations with well-dated mediterranean miocene sections, but also largely depends on the fig. 9 characteristic remnant magnetisation before (panel a) and after (panel b) bedding tilt correction. the left-hand sides of the panels a and b include all the solid-symbol points from fig. 4 from the declination–inclination column. the right-hand sides of the panel (a) and (b) contain all the points after applying the vandamme (1994) cut-off. the left-hand side diagrams of the (b) and (d) panels are presented with no tectonic correction (notc). (c) correction for the inclination error using the method of tauxe & kent (2004). on the left-hand side is the plot of elongation versus inclination for the tk03.gad model, where the black curve shows the variation of the elongation of the dataset distribution with respect to mean inclination when affected by flattening factor ranging from 0.4 to 1.1; the light grey curve is the same for the dataset generated from bootstrap analysis. the corrected inclination is given by the intersection with the dashed line (expected elongation from the tk03.gad). top right-hand diagram from panel c indicates the distribution of the corrected inclinations with a 95% confidence limit. 161vasiliev et al.: palaeomagnetic results from the sarmatian/pannonian boundary... first appearance of the three-toed equid hippotherium in the lower pannonian, at the beginning of the local papp zone c (papp, 1948, 1951; nagymarosy & müller, 1988; rögl & daxner-hock, 1996; steininger et al., 1996). by definition, the first appearance datum (fad) of hippotherium marks the beginning of the vallesian stage and is indicative of neogene mammal zone mn 9. other basal pannonian faunas of rudabanya, gaiselberg, and comanesti–2 also correlate with mn9 (feru et al., 1980; bernor et al., 1988, 2002, 2003; steininger et al., 1990, 1996; rögl & daxner-hock, 1996). the base of the vallesian has, however, recently been directly dated by magnetostratigraphy at 11.1 ma (chron c5r.1r) in the vallès–penedès basin (garcés et al., 1996, 1997; agustí et al., 2001), but the sarmatian/pannonian boundary has not been revised accordingly. we therefore conclude that caution is warranted when using an age of 11.5–11.6 ma for the environmental change from marine to brackish waters in central paratethys, and that more research should be done to obtain better age constraints on the sarmatian/pannonian boundary. acknowledgements the decision to initiate this integrated croatian–dutch research effort on the vranović section at našice was directly related to the informative meetings of the eeden programme of the european science foundation (esf). we thank anita grizelj for her help in the field. željko bortek and ‘našice-cement d.d.’ are thanked for providing access in the našice quarry. this work was sponsored by the netherlands research centre for integrated solid earth sciences (ises) under the programs of the vening meinesz research school of geodynamics (vmsg). the authors gratefully appreciate and acknowledge the reviews by davor pavelić, mathias harzhauser and an anonymous reviewer, whose comments significantly improved this paper. 6. references agustí, j., cabrera, l., garcés, m., krijgsman, w., oms, o. & parés, j.m. (2001): a calibrated mammal scale for the neogene of western europe. state of the art.– earth science reviews, 52, 247–260. agustí, j. & moyà-solà, s. (1991): spanish neogene mammal succession and its bearing on continental biochronology.– newsletters on stratigraphy, 25, 91–144. bakrač, k. (2005): palinološka karakterizacija naslaga srednjeg miocena jugozapadnog dijela panonskog bazena [palinology of the middle and upper miocene deposits from the south-western parts of the pannonian basin – in croatian with english summary].– unpublished phd thesis, university of zagreb, 173 p. baranyi, i., lippolt, h.j. & todt, w. (1976): kalium–argon altersbestimmungen an tertiären vulkaniten des oberrheingraben-gebietes. ii der alterstraverse vom hegau nach lothringen.– oberrhein. geol. abh., 25, 41– 62. barry, j., lindsay, e.h. & jacobs, l.l. (1982): a biostratigraphic zonation of the middle and upper siwaliks of the potwar plateau of northern pakistan.– palaeogeogr. palaeoclimatol. palaeoecol., 37, 95–130. barry, j., johnson, n.m., raza, s.m. & jacobs, l.l. (1985): neogene mammalian faunal change in the southern asia: correlation with climatic, tectonic, and eustatic events.– geology, 13, 637–640. bernor, r.l., kovar-eder, j., lipscomb, d., rögl, f., sen, s. & tobien, h. (1988): systematics, stratigraphic and paleoenvironmental contexts of first-appearing hipparion in the vienna basin, austria.– journal of vertebrate paleontology, 8, 427–452. bernor, r.l., kretzoi, m., mittmann, h.-w. & tobien, h. (1993a): a preliminary systematic assessment of the rudabáanya hipparions (equidae, mammalia).– mitteilungen der bayerischen staatssammulung für paläontologie und historiche geologie, 33, 195–207. bernor, r.l., mittmann, h.-w. & rögl, f. (1993b): systematics and chronology of the götzendorf “hipparion” (late miocene, pannonian f, vienna basin).– annalen naturhist. mus., 95, 101–120. bernor, r.l., kordos, l., rook, l., agustí, j., andrews, p., armour-chelu, m., begun, d., cameron, d.w., damuth, j., daxner-höck, g., de bonis, l., fejfar, o., fessaha, n., fortelius, m., franzen, j., gasparik, m., gentry, a., heissig, k., hernyak, g., kaiser, t., koufos, g.d., krolopp, e., janossy, d., llenas, m., meszáros, l., müller, p., renne, p., rocek, z., sen, s., scott, r., styndlar, z., topal, g., unger, p.s., utescher, t., van dam, j., werdelin, l. & ziegler, r. (2002): recent advances on multidisciplinary research at rudabánya, late miocene (mn9), hungary: a compendium.– paleontographya italica, 89, 3–36. bernor, r.l., armour-chelu, m., kaiser, t.m. & scott, r.s. (2003): an evaluation of the late mn9 (late miocene, vallesian age), hipparion assemblage from rudabánya (hungary): systematic background, functional anatomy and paleoecology.– in: lópez-martínez, n., peláez-campomanes, p. & hernández fernández, m. (eds.): surrounding fossil mammals: dating, evolution and paleoenvironment. coloquios de paleontologia, ext. 1, 35–46. dunlop, d.j. & özdemir, o. (1997): rock magnetism – fundamentals and frontiers.– cambridge university press, 592 p. feru, m., rădulescu, c. & samson, p. (1980): la faune de micromammifères du miocène de comăneşti (dep. d‘arad).– traveaux de l’institute de spéologie “émile racovitza”, 19, 171–190. garcés, m., agustí, j., cabrera, l. & parés, j.m. (1996): magnetostratigraphy of the vallesian (late miocene) in the valles–penedes basin (northeast spain).– earth and planet. sci. lett., 142, 381–396. garcés, m., cabrera, l., agustí, j. & parés, j.m. (1997): old world first appearance datum of “hipparion” 162 geologia croatica 60/2 horses: late miocene large-mammal dispersal and global events.– geology, 25, 19–22. garcés, m., krijgsman, w., peláez-campomanes, p., angeles, m., sierra, a. & daams, r. (2003): hipparion dispersal in europe: magnetostratigraphic constraints from the daroca area (spain).– coloquios de paleontologia, ext. 1., 171–178. harzhauser, m. & piller, w.e. (2004). integrated stratigraphy of the sarmatian (upper middle miocene) in the western central paratethys.– stratigraphy, 1, 65–86. harzhauser, m. & piller, w.e. (2007). benchmark data of a changing sea – palaeogeography, palaeobiogeography and events in the central paratethys during the miocene.– palaeogeogr. palaeoclimatol. palaeoecol., 253, 8–31. harzhauser, m., piller, w.e. & latal, c. (2007). geodynamic impact on the stable isotope signatures in a shallow epicontinental sea.– terra nova, 19, 324–330. horváth, f. & cloetingh, s. (1996): stress-induced late stage subsidence anomalies in the pannonian basin.– tectonophysics, 266, 287–300. jamičić, d. (1995): the role of sinistral strike-slip faults in the formation of the structural fabric of the slavonian mts. (eastern croatia).– geol. croatica, 48/2, 155–160. kappelman, j., sen, s., fortelius, m., duncan, a., alpagut, b., crabaugh, j., gentry, a., lunkka, j.p., mcdowell, f., solounias, n., viranta, s. & werdelin, l. (1996): chronology and biostratigraphy of the miocene sinap formation of central turkey.– in: bernor, r.l., fahlbusch, v. & mittmann, h.w. (eds.): the evolution of western eurasian neogene mammal faunas. columbia university press, new york, 78–95. kirschvink, j.l. (1980): the least-squares line and plane and the analysis of paleomagnetic data.– geophys. j. r. astron. soc., 62, 699–718. korolija, b. & jamičić, d. (1988): osnovna geološka karta sfrj 1:100000, list našice (basic geological map of sfrj 1:100000, našice sheet).– inst. za geol. istraž., zagreb, sav. geol. zavod, beograd. kovác, m., nagymarosy, a., oszczypko, n., csontos, l., slaczka, a., marunteanu, m., matenko, l. & márton, e. (1998): palinspastic reconstruction of the carpathian–pannonian region during the miocene.– in: rakus, m. (ed.): geodynamic development of the western carpathians. guds bratislava, dionyz stúr publishers, 198–217. kovačić, m. (2004): sedimentologija gornjomiocenskih naslaga jugozapadnog dijela panonskog bazena [sedimentology of the upper miocene deposits from the southern part of the pannonian basin – in croatian with english summary].– unpublished phd thesis, university of zagreb, 203 p. kovačić, m. & grizelj, a. (2006): provenance of upper miocene clastic material in the southwestern part of the pannonian basin.– geologica carpathica, 57, 495–510. krijgsman, w., garcés, m., langereis, c.g., daams, r., van dam, j., van der meulen, a.j., agustí, j. & cabrera, l. (1996): a new chronology for the middle to late miocene continental record in spain.– earth and planet. sci. lett., 142, 367–380. magyar, i., geary, d.h. & müller, p. (1999): paleogeographic evolution of the late miocene lake pannon in central europe.– palaeogeogr. palaeoclimatol. palaeoecol., 147, 151–167. márton, e., pavelić, d., tomljenović, b., avanić, r., pamić, j. & márton, p. (2002): in the wake of a counterclockwise rotating adriatic microplate: neogene paleomagnetic results from the northern croatia.– int. j. earth. sci., 91, 514–523. mullender, t.a.t., van velzen, a.j. & dekkers, m.j. (1993): continuous drift correction and separate identification of ferromagnetic and paramagnetic contribution in thermomagnetic runs.– geophys. j. int., 114, 663–672. nagymarosy, a. & müller, p. (1988): some aspects of the neogene biostratigraphy in the pannonian basin.– in: royden, l.h. & horváth, f. (eds.): the pannonian basin. a study in basin evolution. aapg mem., 45, 69– 77. papp, a. (1948): fauna und gliederung der congerienschichten des pannons im wiener becken.– anz. akad. wiss. wien, 85, 123–34. papp, a. (1951): das pannon des wiener beckens.– mitteilungen der geologischen gesellschaft in wien, 34–41, 99–193. pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.– basin research, 13, 359–376. pavelić, d., kovačić, m., miknić, m., avanić, r., vrsaljko, d., bakrač, k., tišljar, j., galović, i. & bortek, z. (2003): the evolution of the miocene environments in the slavonian mts. area (northern croatia).– in: vlahović i. & tišljar j. (eds.): evolution of depositional environments from the palaeozoic to the quaternary in the karst dinarides and the pannonian basin. 22nd ias meeting of sedimentology, opatija – september 17–19, 2003, field trip guidebook, 173–181, zagreb. piller, w.e. & harzhauser, m. (2005): the myth of the brackish sarmatian sea.– terra nova, 17, 450–455. prelogović, e., saftić, b., kuk, v., velić, j., dragaš, m. & lučić, d. (1998): tectonic activity in the croatian part of the pannonian basin.– tectonophysics, 297, 283–293. rögl, f. (1996): migration pathways between africa and eurasia. oligocene–miocene paleogeography.– europal, 10, 23–26. rögl, f. & daxner-höck, g. (1996): late miocene paratethys correlation.– in: bernor, r.l., fahlbusch, v. & mittmann, h.-w. (eds.): the evolution of the western eurasian neogene mammal faunas. columbia university press, new york, 47–55. royden, l.h. (1988): late cenozoic tectonics of the pannonian basin system.– in: royden, l.h. & horváth, f. (eds.): the pannonian basin. a study in the basin evolution. am. assoc. petrol. geol. mem., 45, 27–48. 163vasiliev et al.: palaeomagnetic results from the sarmatian/pannonian boundary... sandulescu, m. (1988): cenozoic tectonic history of the carpathians.– in: royden, l.h. & horváth, f. (eds.): the pannonian basin. a study in basin evolution, aapg memoir, 45, 17–25. sen, s., valet, j.-p. & ioakim, c. (1986): magnetostratigraphy and biostratigraphy of the neogene deposits of kastellios hill (central crete, greece).– palaeogeogr. palaeoclimatol. palaeoecol., 53, 321–334. steininger, f.f. & rögl, f. (1985): die palaogeographie der zentralen paratethys im pannonien.– in: papp, a., jambor, a. & steininger, f.f. (eds.): m6–pannonien (slavonien und serbien) – serie chronostratigraphie und neostratotypen. miozän der zentralen paratethys, akad. kiado, budapest. 7, 46–50. steininger, f.f., müller, c. & rögl, f. (1988): correlation of central paratethys, eastern paratethys, and mediterranean neogene stages.– in royden, l.h. & horváth, f. (eds.): the pannonian basin. a study in basin evolution, aapg memoir, 45, 79–87. steininger, f.f., bernor, r.l. & fahlbusch, v. (1990): european neogene marine/continental chronologic correlations.– in: lindsay, e.h., fahlbusch, v. & mein, p. (eds.): european neogene mammal chronology. plenum, new york, 15–46. steininger, f.f., berggren, w.a., kent, d.v., bernor, r.l., sen, s. & agustí, j. (1996): circummediterranean neogene (miocene and pliocene) marine–continental chronologic correlation of the european mammal units.– in: bernor, r.l., fahlbusch, v. & mittmann, h.w. (eds.): the evolution of the western eurasian neogene mammal faunas. columbian univ. press, new york, 7–46. sütő-szentai, m. (1988): microplankton zones of organic skeleton in the pannonian s.l. stratum complex and in the upper part of the sarmatian strata.– acta botanica hungarica, 34/3–4, 339–356. tari, g., horváth, f. & rumpler, j. (1992): styles of extension in the pannonian basin.– tectonophysics, 208, 203–219. tauxe, l. & kent, d.v. (2004): a simplified statistical model for the geomagnetic field and the detection of shallow bias in paleomagnetic inclinations: was the ancient magnetic field dipolar?– in: channell, j.e.t., kent, d.v., lowrie w. & meert, j. (eds.): timescales of the paleomagnetic field. agu geophysical monograph, 145, 101–115. vakarcs, g., vail, p.r., tari, g., pogacsas, g., mattick, r.e. & szabo, a. (1994): third-order middle miocene–early pliocene depositional sequences in the prograding delta complex of the pannonian basin.– tectonophysics, 240, 81–106. vandamme, d. (1994): a new method to determine paleosecular variation.– phys. earth planet. int., 85, 131–142. woodburne, m.o. & swisher, c.c. (1995): land mammal high-resolution geochronology, intercontinental overland dispersals, sea-level, climate, and variance.– in: berggren, w.a., kent, d.v. & hardenbol, j. (eds.): geochronology, time scale and global stratigraphic correlations: a unified temporal framework for a historical geology. sepm (society for sedimentary geology) special publication, 54, 329–358. manuscript received may 2, 2007. revised manuscript accepted november 23, 2007. 164 geologia croatica 60/2 gc 57-2.indb 1. introduction in the lower cretaceous of croatia, notwithstanding the remarkable stratigraphic development of shallow water carbonate platforms, rudist bearing sediments are rare and/or poorly documented. rudist faunas have been hitherto mentioned from the following localities: – in istria, in the kanfanar–dvigrad area, where toucasia rich beds from the kanfanar formation, of early aptian age, were acknowledged (tišljar, 1978; vlahović et al., 2002, among others). the veli brijun island also exposes a remarkable requieniid rich locality of aptian–albian age (velić & tišljar, 1987), – in the lika region, near korenica, “offneria rhodanica” paquier was collected by polšak (1970) in aptian limestones, – tounj, near ogulin where the presence of requieniids was indicated by velić & sokač (1978, 1979) in aptian limestones, lower aptian rudist faunas (bivalvia, hippuritoidea) from croatia jean-pierre masse1, mukerrem fenerci-masse1, tvrtko korbar2 and ivo velić2 – from svilaja mt., in the hinterland of split, caprinid facies including a few offneria sp. and glossomyophorus costatus masse, skelton & slišković of early aptian age was reported by cvetkotešović et al. (2003). the foregoing shows that the aptian is a key stage for lower cretaceous rudist studies in croatia, as well as in adjacent regions: in slovenia, where aptian caprinids have been described by pleničar & buser (1967) and turnšek et al. (1992), and in bosnia, where caprinids and caprotinids have been studied by masse et al. (1984). the objective of the present paper is to specify the taxonomic position of lower aptian rudists found in the kanfanar area of istria, and the tounj area of central croatia (fig. 1). this study is based on material collected from these two areas and includes the taxonomic reappraisal of caprinids figured from the lika region, slovenia and bosnia. the present contribution includes a description of the regional stratigraphy followed by a systematic palaeontological study of the rudist material. the faunal assemblages are subsequently discussed in terms of biostratigraphy, palaeoecology, palaeogeography and palaeobiogeography. 2. stratigraphic setting lower aptian shallow water carbonates are widely distributed along the croatian part of the karst dinarides, i.e. within deposits of an ancient adriatic carbonate platform (adcp). the carbonates were deposited within different platform environments, most frequently within extensive lagoons and protected shallow peritidal settings, rarely within bioconstructed bodies. orbitolinidbearing limestones are widespread. rudists appear as the coarsest bioclasts within floatstones intercalated in orbitolinid-bearing limestones or within skeletal carbonate bodies. there are two well investigated areas in croatia that are characterized by relatively rudist-rich limestones – western istria and an area surrounding the town of ogulin in central croatia (fig. 1). 2.1. kanfanar area in western istria – – western croatia the stratigraphic succession of jurassic and cretaceous platform carbonates in western istria is divided into geologia croatica 57/2 117–137 13 figs. 3 pls. zagreb 2004 key words: rudist faunas, lower aptian, lower cretaceous, adriatic carbonate platform, croatia. 1 centre de sédimentologie et paléontologie, université de provence, umr 6019–cnrs, f-13331 marseille, cedex 3, france; e-mail: jpmasse@up.univ-mrs.fr 2 institute of geology, p.o. box 268, sachsova 2, p.o. box 268, hr-10000 zagreb, croatia. abstract lower aptian rudist faunas from croatia consist of requienia? zlatarskii paquier, toucasia sp., agriopleura sp., glossomyophorus costatus masse, skelton & slišković, himeraelites sp. and offneria sp. this assemblage has a clear southern tethyan (arabo– african) significance and typifies the early aptian. faunas from the interior of the adriatic carbonate platform in istria are dominated by requieniidae while those from the northeastern area in the vicinity of tounj–ogulin, close to the platform margin, exhibit a higher diversity and include, beside requieniids, caprinidae, caprotinidae and monopleuridae, in conjunction with evidence of open marine conditions. 118 geologia croatica 57/2 119masse et al.: lower aptian rudist faunas (bivalvia, hippuritoidea) from croatia three megasequences (velić et al., 1995) bounded by major discontinuities – emersion surfaces representing time periods of subaerial exposure characterized by scattered accumulation of bauxite laterites. the megasequences are of the following chronostratigraphical ranges (velić et al., 2002): bathonian–lower kimmeridgian (i), upper tithonian–upper aptian (ii) and upper albian–upper santonian (iii). the best outcrops of aptian carbonates of western istria are exposed in the kanfanar area (fig. 2). they represent the uppermost part of the second megasequence. relatively uniform lithologies imply that the carbonates were deposited within a generally stable lagoonal environment. as a result of late aptian–early albian subaerial exposure and subsequent erosion, the thickness of lower aptian carbonates is highly variable, i.e. they are locally absent (see fig. 1 in velić et al., 1989). owing to its commercial value, lower aptian limestones with rudists in istria are relatively well investigated from a stratigraphic and palaeoenvironmental point of view. the commercial name of the deposits is “istrian yellow” (velić & hvala, 2002). the limestones have been studied in detail along sections in the lim valley and kanfanar quarry (fig. 3; velić et al., 1995; tišljar et al., 1995; vlahović, 1999; fig. 1 location map. fig. 2 geological sketch-map of the kanfanar area. 118 geologia croatica 57/2 119masse et al.: lower aptian rudist faunas (bivalvia, hippuritoidea) from croatia vlahović, et al., 2002). bacinella-rich beds are the dominant facies, and these include scattered rudists (fig. 3). the succession of aptian carbonates around kanfanar has been described in detail by velić et al. (1995) and vlahović (1999). underlying barremian gastropod grainstones (bed a in fig. 3), are overlain by a massive and compact 19.5 m thick interval of oncoid-bearing lower aptian limestones (figs. 4 and 5). vlahović (1999) assigned these aptian carbonates to a unique informal kanfanar fm. consisting of a lower sv. petar mb. (lower aptian massive oncoidbearing limestones), and an upper begovac mb. (topmost lower aptian and upper aptian limestones). the sv. petar mb. shows a basal interval (2 m thick) composed of rhythmic alternations of bacinella-oncoid floatstones and mudstones (interval b in fig. 3). the interval is overlain by an approximately 2.50 m thick bacinella-oncoid floatstone containing rudists (beds c in fig. 3) described in section 3. overlying the main rudist bed, the main mass of bacinella-oncoid floatstones containing rare requieniid shells is approximately 15 m thick (interval b’ in fig. 3). besides bacinella irregularis radoičić, the limestones are characterized by a typical lower aptian microfossil association, including: salpingoporella dinarica radoičić, palorbitolina lenticularis (blumenbach), sabaudia briacensis arnaud-vanneau, fig. 3 stratigraphic column of aptian carbonates in the kanfanar area (modified after velić et al., 1995). 120 geologia croatica 57/2 121masse et al.: lower aptian rudist faunas (bivalvia, hippuritoidea) from croatia s. minuta (hofker), vercorsella scarsellai (de castro), v. laurentii (sartoni & crescenti), novalesia distorta arnaud-vanneau, praechrysalidina infracretacea luperto-sinni, debarina hahounerensis fourcade et al., mayncina bulgarica laug et al., voloshinoides murgensis luperto-sinni & masse, archaealveolina sp. and very rare, but biostratigraphically very important, praeorbitolina cormyi schroeder. above the bacinella-oncoid floatstones an approximately 2.7 m thick interval of bioclastic–skeletal grainstones occurs (interval d in fig. 3) containing palorbitolina lenticularis and other orbitolinids (mostly broken), primitive alveolinids, pseudonummoloculina aurigerica calvez and rare pseudolituonella conica luperto-sinni & masse. the interval previously described as bacinellaoncoid beds is biostratigraphically assigned to the palorbitolina lenticularis taxon-range zone (velić et al., 1995). the aforementioned deposits are followed by a 1.5 m thick interval of bioclastic grainstones containing rudist bioclasts (bed e in fig. 3) that represent a transitional interval between lower and upper aptian deposits in istria. it is continuously overlain by a thin upper aptian sequence consisting of a 0.5 to 1.5 m thick bivalve coquina containing salpingoporella dinarica and praechrysalidina infracretacea (bed f in fig. 3), and by 0.7 to 2.5 m thick biomicrite with abundant s. dinarica, frequent p. infracretacea and miliolids (interval g in fig. 3). these upper aptian deposits were assigned by velić et al. (1995) to the salpingoporella dinarica abundance zone. the overlying emersion breccia and conglomerates, 1.0 to 2.5 m thick, were deposited during the emersion phase from the early late aptian to the early late albian. they are followed by wackestones to packstone/grainstones containing the following late albian orbitolinid and other foraminiferal association: “valdanchella” dercourti decrouez & moullade, neoiraquia insolita (decrouez & moullade), paracoskinolina fleuryi decrouez & moullade, pseudonummoloculina aurigerica calvez, p. heimi (bonet), cuneolina pavonia (d’orbigny), c. parva henson, sabaudia auruncensis (chiocchini & di napoli), s. minuta (hofker), vercorsella scarsellai (de castro), v. laurentii (sartoni & crescenti), mayncina bulgarica laug, etc. finally, it could be concluded that frequent rudist occurrences are limited to the lower aptian bacinellaoncoid floatstones – within interval c in fig. 3, and the bioclastic grainstones representing the transition from the lower to the upper aptian – bed e in fig. 3. rudists occur sporadically within the bacinella-oncoid intervals b and b’ in fig. 3. 2.2. tounj and ogulin area – central croatia lower aptian platform carbonates in the vicinity of ogulin (fig. 6) are characterized by palorbitolina-limestones (“lower orbitolinid limestones” sensu velić & sokač, 1978) comprising intercalations of kilometrelong bioclastic–skeletal bodies containing rudists. in contrast to sections in istria, it is impossible to measure and to describe in detail the lower aptian deposits in the area of ogulin–tounj due to tectonic disturbance and widespread neogene and quaternary cover (figs. 6 and 8). therefore, the overall facies characteristics of the deposits will be described in a general manner. according to facies characteristics, the lower aptian carbonate platform succession of the tounj area can be subdivided into two parts (fig. 7). the lower part is represented by orbitolinid-rich (palorbitolina and praeorbitolina) wackestones characterized by the presence of calcisphaeres and scattered pelagic microfossils – hedbergella sp., saccocoma sp. and some lageniids, suggesting an influence from the open sea (velić & sokač, 1978). fig 4 panoramic view of the northern slope of lim valley (north of kanfanar) showing the undisturbed lower cretaceous well-bedded carbonate succession. the massive bed of lower aptian bacinella oncolite (upper third of the succession) is 19.5 m thick. fig. 5 polished slab of massive lower aptian bacinella oncolite from kanfanar quarry containing requieniid shells. these limestones are the well-known architectural-building stone named “istrian yellow”. 120 geologia croatica 57/2 121masse et al.: lower aptian rudist faunas (bivalvia, hippuritoidea) from croatia in the upper part of the lower aptian deposits, upwardly and laterally to the aforementioned orbitolinid limestones, there are massive, coarse-grained bioclastic–skeletal floatstones to rudstones and skeletal bodies that also contain benthic foraminifera, mainly orbitolinids. rudists (see section 3) are associated with corals and gastropods, and fragments of bryozoans, stromatoporoids and other encrusting organisms. terminal beds of the lower aptian, deposited in subtidal–lagoon environments, also belong to the orbitolinid limestones and open marine influences are recorded. upper aptian deposits are in normal, continuous succession and are characterized by an alternation of algal (salpingoporella dinarica) wackestones and orbitolinid-rich (mesorbitolina parva–texana group) packstones/grainstones. they were deposited in shallow, low current-energy subtidal to higher current-energy peritidal environments during shallowing upward cycles. the overall thickness of the lower aptian deposits in the tounj area can be estimated as more than 300 m (fig. 7), three times the average thickness in the surrounding terrain of central croatia where it is less than 100 m. this is due to high bioclastic–skeletal production in coral/rudist environments coupled with the provision of a lot of accommodation space. biostratigraphically, aptian deposits are characterized by development of palorbitolina-limestones during the early aptian (“lower orbitolinid limestones” sensu velić & sokač, 1978, and velić, 1988), and fig. 6 geological sketch map of the ogulin–tounj area (after velić & sokač, 1981). 122 geologia croatica 57/2 123masse et al.: lower aptian rudist faunas (bivalvia, hippuritoidea) from croatia both maximal development of the alga salpingoporella dinarica radoičić and the first appearance of large mesorbitolina during the late aptian. the complete succession of the “lower orbitolinid limestones” corresponds to the stratigraphic range of palorbitolina lenticularis (blumenbach). they contain other early aptian index-fossils including praeorbitolina cormyi schroeder, p. wienandsi schroeder, orbitolina (mesorbitolina) lotzei schroeder, sabaudia briacensis arnaud-vanneau, neotrocholina friburgensis guillaume & reichel, n. aptiensis jovčeva, derventina filipescui neagu associated with foraminifera of wider stratigraphic range as well as with rare occurrences of salpingoporella dinarica radoičić. biostratigraphically, these deposits could be assigned to the palorbitolina lenticularis taxon-range zone. fig. 7 stratigraphic column of the upper baremian–lower aptian in the ogulin–tounj area. 122 geologia croatica 57/2 123masse et al.: lower aptian rudist faunas (bivalvia, hippuritoidea) from croatia the stratigraphic position of the rudist-containing bodies in the wider area of tounj, i.e. in central croatia, is within the upper part of the bedoulian. it corresponds to the range of p. wienandsi and o. (m.) lotzei, in association with other aforementioned benthic foraminifera. limestones characterized by the mass appearance of the alga salpingoporella dinarica (s. dinarica abundance zone) overlie the described lower aptian deposits in the area of tounj, similar to the precisely described aptian facies development in istria (see section 2.1.). upwardly, the first appearance of the large mesorbitolina indicates the presence of gargasian deposits. 3. systematic palaeontology the repository of rudist specimens described in the present paper is at the centre de sédimentologie–paléontologie, université de provence, marseille. nevertheless, owing to the fact that most of the studied material was observed on natural outcrops of more or less compact and massive limestones, the corresponding specimens are expected to be still “in situ”. the symbols used for descriptions are as follows: uv – upper valve; lv – lower valve; d – dorsal side; v – ventral side; a – anterior side; p – posterior side; pmp – posterior myophoral plate; pmc – posterior myophoral cavity; pm – posterior myophore; am – anterior myophore; at – anterior tooth; as – anterior socket; ct – central tooth; pt – posterior tooth; ps – posterior socket; bc – body cavity; cp – cardinal platform; l – ligament crest/dorso-ventral axis; com – commissure; ab – anterior band; pb – posterior band; ib – interband; cl – outer calcitic shell layer; hcp – horizontal concave partitions; tab – body cavity tabulae. order hippuritoida newell, 1965 superfamily hippuritoidea gray, 1848 family requieniidae douville, 1915 genus requienia matheron, 1842 requienia? zlatarskii paquier, 1903 pl. i, figs. 1–7 at kanfanar quarry, besides toucasia as formerly mentioned by various authors (see in vlahović et al., 2002), requieniids are represented by numerous sections showing: – a lower valve with a lamellar anterior side, a smooth posterior side, a pronounced, acute, ventral carina, and lacking a myophoral plate (pi. i, figs. 1, 3, 4, 7), – a moderately convex upper valve with a well-defined body cavity (pi. i, figs. 1, 2, 4, 5), – on both valves, a cardinal platform extending over nearly 1/3 of the dorso-ventral axis (pi. i, figs. 4, 5). the apparent absence of myophoral processes in both valves and the relatively wide development of the cardinal platform suggest muscle attachment onto this platform. assuming that this interpretation is correct, this leads us to exclude the present material from requienia, because the genus is characterized by a posterior myophoral plate in the upper valve (douville, 1915). similarly matheronia seems inadequate because in the representatives of this genus (especially matheronia virginiae gras, the type species) the cardinal fig. 8 tounj quarry. fault contact (in the centre of the photograph) of well-bedded albian limestones (k1 6, on the left) and thick-bedded to massive lower aptian rudist limestones (bk1 5, on the right). elevation from the bottom to the top of the quarry is approx. 80 m, comprising an approximately equally thick part of the lower aptian succession. 124 geologia croatica 57/2 125masse et al.: lower aptian rudist faunas (bivalvia, hippuritoidea) from croatia platform is poorly developed and muscle attachment is on the walls of both valves (paquier, 1903; douville, 1915). lovetchenia possesses a wide cardinal platform on both valves but muscles are attached on the widened and thickened commissural edges (masse, 1993). notwithstanding the foregoing difficulties to find a genus for housing our material we tentatively place it close to requienia zlatarskii paquier (paquier, 1903). this form and requienia petersi toula as well (toula, 1902) posses a lower valve with a lamellar anterior side, a smooth posterior side, an acute ventral carina, while the upper valve is slightly convex. whereas r. zlatarskii displays a small myophoral plate on the posterior side of the upper valve the internal characters of requienia petersi are nearly unknown. because the later was poorly described r. zlatarskii appears more appropriate for our material. genus toucasia munier chalmas, 1873 toucasia sp. pi. ii, figs. 1–6 in the kanfanar area this genus is represented by numerous randomly oriented sections of isolated lower valves or bivalve specimens, with several whorls (pi. ii, figs. 2, 3). the lower valve shows a rounded posterior side and a nearly flat anterior side. the dorso–ventral axis (dv) ranges from 5 to 8 cm, while the antero–posterior one (ap) fluctuates from 4 to 6 cm. the corresponding ratio (ap/dv) is therefore 0.8 to 0.75, a value close to those of toucasia carinata matheron (masse et al., 1998a). on juvenile specimens and/or sections of the juvenile part of the shell the junction between the posterior and the anterior site is characterized by an acute ventral carina (pi. ii, fig. 4) which tends to disappear in adults (pi. ii, figs. 2, 3, 5, 6). the posterior myophoral plate of the lower valve, a diagnostic attribute of the genus, corresponds externally to a dark line and/or a small groove. the transverse section of the myophoral plate has a low triangular shape on both valves (pi. ii, figs. 2, 3, 5, 6). at tounj toucasia is also present. in both localities the absence of complete, isolated specimens, precludes a precise identification of the species. family monopleuridae munier chalmas, 1873 genus agriopleura kühn, 1932 fig. 9 (a–b) at tounj, longitudinal sections ascribed to this genus are characterised by a triangular shaped lower valve indicating a conical morphology and a depressed, concave upward, upper valve (fig. 9). the lower valve has a smooth outer surface. sections with elongated slender teeth and myophoral bulges connected to the inner side of the upper valve are also present. thin sections, cut in the rock bearing agriopleura specimens, show the acellular outer shell (calcitic) layer with an oblique, sometimes wavy growth banding (fig. 9b). the absence of well preserved transverse sections preclude observation of the radial bands and the overall configuration of the myocardinal apparatus, especially the ligamental crest and surrounding cavities, all characters with strong taxonomic implications at the species level. fig. 9 agriopleura sp., tounj. (a) field photograph showing a bouquet-like aggregation of mainly upward oriented (life position) shells. the typical attributes of the genus are: a) concave upper valve, b) sub-triangular outline of the lower valve, c) elongated teeth. (b) longitudinal oblique thin section showing a compact shell structure with growth banding. 124 geologia croatica 57/2 125masse et al.: lower aptian rudist faunas (bivalvia, hippuritoidea) from croatia family caprotinidae (gray, 1848) skelton, 1978 genus glossomyophorus masse, skelton & slišković, 1984 glossomyophorus costatus masse, skelton & slišković, 1984 fig. 10 (a–b) our material was collected at tounj and is mainly represented by transverse sections of the lower valve with an elliptical outline (linked to a dorso–ventral compression) and a well defined (dark coloured), strongly ribbed, outer shell layer. the ventral zone shows a relatively wide slightly elevated anterior band and a narrow, ribbed and salient, posterior band. the interband corresponds to a narrow acute groove. notice that in sections close to the apex the shell outline is nearly circular with some antero–posterior compression and the outer shell ornamentation less vigorous especially on the dorsal side. internal characters consist of a row of three holes: two sockets and a myophoral cavity for the teeth and the myophoral plate of the opposite valve, respectively. all these attributes conform to the definition of glossomyophorus costatus masse, skelton & slišković (1984). family indet. genus himeraelites di stefano, 1889 himeraelites sp. pi. iii, figs. 1–4 we ascribe to this genus a set of transverse sections of the lower valve found at tounj. the outline is rounded with a slightly antero–dorsal–postero–ventral compression. the dorso–ventral axis (dv) is 3.2 to 4 cm in long, while the antero–posterior one (ap) is 2.5 to 3 cm. the corresponding ratio (ap/dv) is therefore 0.75 to 0.85. nevertheless, it is about 1 close to the apex. the outer shell layer is very thin (about 1 mm) with fine costulation which is frequently missing (due to micritization) while the inner (originally aragonitic) shell layer is thick (1.6–1.8 cm) on the dorsal side and thinner on the ventral side (0.3–0.4 cm). owing to the sparitisation of the dorsal side, the cardinal elements are poorly defined, nevertheless the acute central tooth and the adjacent anterior socket are frequently detectable through the paramorphic preservation of antecedent aragonitic structures (pi. iii, figs. 2–4). the thin ligamental cavity is bent towards the anterior side and deeply penetrates into the dorsal side until the central tooth. there is an anterior inner thickening corresponding to the anterior myophore, the posterior one is assumed to be located on the thickened posterior side. family caprinidae d’orbigny, 1847 genus offneria paquier, 1905 fig. 11 (a–b) from central croatia, polšak (1970) described offneria rhodanica paquier represented by a portion of the upper valve showing the diagnostic attributes of the genus offneria. whether the figured specimen (polšak, 1970, fig. 2, p. 147) belongs to o. rhodanica or o. murgensis masse (masse, 1992) is not clear. in contrast, figures of rudist specimens from southwestern slovenia (trnovski gozd), provided by pleničar & buser (1967), identified as caprina cf. douvillei paquier and offneria rhodanica paquier, clearly belong to offneria murgensis masse. this assignment is based on the complex canal network observed on specimens from plate ii, figs. 1 and 2 of pleničar & buser (1967), whereas fig. 2 illustrates a lower valve with a well developed canal system (a feature unknown in caprina douvillei ), while the canal organisation of offneria rhodanica is more simple, especially at the fig. 10 glossomyophorus costatus, tounj. (a) transverse section of a lower valve showing the main attributes of the species: ornamentation, radial bands and internal myocardinal characters. (b) interpretation of a. 126 geologia croatica 57/2 127masse et al.: lower aptian rudist faunas (bivalvia, hippuritoidea) from croatia articulation between the ventral and posterior sides of the shell. on plate v, fig. 2 in pleničar & buser (1967) a similar configuration is shown. offneria rhodanica collected in the kladanj area (bosnia) and mentioned by masse et al. (1984) has not been described nor illustrated hitherto. a reappraisal of this material (lower valve housed in masse collection) shows the following characters (fig. 11): – the ventral side bears a continuous row of canals and is slightly depressed; canal walls are bifurcated at the posterior/ventral junction, – on the posterior side the inner row of wide canals flanking the myophoral plate is surrounded externally by a row of numerous small canals, – on the anterior side there are several rows of polygonal or rounded canals, the size of which decreases outward, – the body cavity possesses tabulae, – horizontal concave partitions are present locally in canals having a relatively large size, – vertical walls dividing canals are common, – the thin calcitic outer shell layer is preserved near the articulation between the anterior and ventral sides. this set of characters typifies offneria murgensis masse (masse, 1992; chartrousse, 1998). 4. discussion 4.1. biostratigraphy toucasia is documented from the upper hauterivian (masse et al., 1998d) to the albian (douville, 1915; masse, 1996). agriopleura is also known to appear in the upper hauterivian (masse, 1996; masse et al., 1998b) and became extinct in the midaptian. himeraelites was originally described from the albian–cenomanian (di stefano, 1889) and possesses a significant record in the albian from italy (masse et al., 1998c). it was also documented from the upper aptian of algeria (chikhi aouimeur, 1983), from the mid-aptian of saudi arabia (hughes, 1998), and the lower aptian of southern italy (masse, 1992). there is no clear taxonomic framework for prealbian species, the detailed biostratigraphic distribution of which is therefore unknown. requienia zlatarskii was found by paquier (1903) in bulgaria, in beds ascribed to the barremian. closely related forms were also mentioned by paquier (1908) from serbia in orbitolinid limestones considered barremian to lower aptian in age. r. cf. zlatarskii was identified by one of the present authors (jpm) in the lower aptian of bosnia and in southern dobrodja (romania), too. a closely related form was figured from the zonguldak area (western pontids – turkey, masse et al., in press) and from algeria (fliert, 1952), but in the latter case figures are lacking. glossomyophorus costatus and offneria are typical lower aptian species (masse et al., 1984; masse, fig. 11 offneria murgensis, kladanj, bosnia. (a) transverse section of the lower valve showing the canal architecture and myocardinal elements. (b) interpretation of a. 126 geologia croatica 57/2 127masse et al.: lower aptian rudist faunas (bivalvia, hippuritoidea) from croatia 1992; baron-szabo & steuber, 1996; masse et al., 1998b; skelton & masse, 2000). in conclusion, notwithstanding taxonomic uncertainties concerning the species of toucasia, agriopleura, and himeraelites, the presence of requienia? zlatarskii, glossomyophorus costatus and offneria murgensis suggests an early aptian age for the croatian faunas. this is also in accord with the micropalaeontological data. 4.2. palaeoecology and palaeogeographic setting early aptian times represented a significant change in platform settings, relative to antecedent valanginian–barremian conditions. while pre-aptian platforms in the region were dominated by intertidal or restricted subtidal conditions without rudists, the aptian was marked by the onset of more open conditions with the dominance of subtidal settings where rudists have a significant record. this trend is also documented on neighbouring periadriatic platforms where the early aptian appears to have been a golden age for rudist development (sartorio, 1986, 1987; masse, 1992). oligospecific associations of toucasia and requienia? zlatarskii found at kanfanar in a muddy substrate document the proximal zone of the inner platform rudist bearing domain, excluding severely restricted subtidal and intertidal settings. more diverse rudist faunas including glossomyophorus, and himeraelites, as well as corals, stromatoporoids, hydrozoans, bryozoans, etc., with a tendency for shell aggregation, found at tounj, tend to indicate the distal zone of the inner platform rudist-bearing domain, i.e. more open setting than those at kanfanar. rudists and other organisms flourished within a high energy belt where skeletal remains accumulated or were transported locally, either basinward into a relatively deeper subtidal or backward – into a restricted lagoon, behind prograding bioclastic–skeletal bodies. similar settings may be expected for the offneria-bearing sediments from central croatia, by comparison with palaeoecological models from the middle east (masse et al., 1998b; borgomano et al., 2002). the recent extent of the adriatic carbonate platform (adcp) deposits and position of the discussed aptian fig. 12 recent extent of adriatic carbonate platform deposits (1) and surrounding domains, showing the position of lower aptian rudist-rich skeletal limestones (2). 128 geologia croatica 57/2 129masse et al.: lower aptian rudist faunas (bivalvia, hippuritoidea) from croatia deposits (fig. 12; dragičević & velić, 2002), provide a clue for understanding the palaeoenvironmental settings. kanfanar was located in the inner part of the platform, possibly 50 km from the platform edge, facing the belluno basin. in contrast, tounj was situated close to the platform edge facing the slovenian–bosnian basin. these locations may also explain the vertical development of rudist-rich limestones in the two areas. the kanfanar area may be regarded as a relatively stable, i.e. low or moderately subsiding, platform interior. however, the platform edge facing the slovenian–bosnian basin is known as a dynamic, unstable and tectonized margin (e.g. charvet, 1970; cousin, 1973; blanchet, 1975; jelaska, 1987; buser, 1989; pamić et al., 1998; dragičević & velić, 2002, etc.), expected to promote strongly subsiding blocks and possibly an outer platform escarpment. 4.3. palaeobiogeography in aptian times toucasia had a wide extent in the mediterranean and outside the mediterranean regions (masse, 1985). agriopleura had also a wide extent in the mediterranean region and occurred on african and european tethyan margins (masse, 1985). in france and switzerland, agriopleura species are recorded in the upper hauterivian–barremian and are missing in the lower aptian. in contrast in the arabo–african domain, agriopleura is mainly documented from the lower aptian (masse, 1992; hughes, 1998; skelton & masse, 2000). this contrasting palaeobiogeographical distribution through time suggests an african affinity for the croatian agriopleura. requienia zlatarskii (see biostratigraphy) seems to be a balkan element present on both european and african margins, but with a restricted palaeobiogeographical distribution, running from the pontides to serbia and bosnia through moesia. croatia is the southernmost location of this species (fig. 13). glossomyophorus costatus was firstly recognized from saudi arabia, southern italy and bosnia (masse et al., 1984). it has currently been widely observed in other regions of the eastern mediterranean and middle east (oman, united arab emirates, somalia, northern italy, greece and north africa – skelton & masse, 2000; fig. 13). this species is therefore a south tethyan (arabo–african) palaeobiogeographical marker. offneria murgensis, the presence of which is highly suspected in central croatia but well established in slovenia and bosnia, is also an arabo–african form (masse, 1992; hughes, 1998; masse et al., 1998b). 5. conclusion lower aptian rudist faunas investigated at kanfanar (istria) and tounj (central croatia) consist of requieniidae: requienia? zlatarskii, toucasia sp. (close to t. carinata), monopleuridae: himeraelites sp. and agriofig. 13 palaeogeographic reconstruction of the mediterranean and middle east tethyan domain during the early aptian (modified, after masse et al., 1993) showing the distribution of glossomyophorus costatus in the arabo–african margin, and requienia zlatarskii restricted to the balkans and black sea region of turkey. 128 geologia croatica 57/2 129masse et al.: lower aptian rudist faunas (bivalvia, hippuritoidea) from croatia pleura sp., caprotinidae: glossomyophorus costatus, and caprinidae: offneria sp., probably o. murgensis. besides the typical early aptian species (offneria murgensis and glossomyophorus costatus), poorly defined species of himeraelites and agriopleura, also have lower aptian affinities. the associated benthic foraminifera, mainly the palorbitolina–praeorbitolina doublet, corroborates the foregoing age assignment. the croatian rudist assemblage closely resembles the italian one although some elements (glossomyophorus, offneria) have been reported from neighbouring areas of slovenia and bosnia. notwithstanding its south tethyan (arabo–african) palaeobiogeographic significance this assemblage also shows balkan forms (requienia? zlatarskii). faunas from kanfanar are dominated by low diversity (requienia? zlatarskii, toucasia) and low density assemblages associated with bacinella dominated biotopes, in relatively restricted settings of the adriatic carbonate platform interior. in contrast, faunas from tounj are more diverse (toucasia, glossomyophorus, himeraelites and agriopleura) and consist of densely packed assemblages associated with corals and other encrusting organisms. the corresponding thick congregations mark the proximity to an outer margin of the adriatic carbonate platform, facing the slovenian–bosnian basin, and open marine conditions. acknowledgements this paper has benefited from the careful review of th. steuber (bochum, germany) and p.w. skelton (milton keynes, united kingdom) who helped to improve our manuscript. this paper resulted from the projects umr 6019–cnrs (centre de sédimentologie et paléontologie, université de provence, marseille, france), and no. 0181001 and 0181009 supported by ministry of science, education and sport of the republic of croatia. 6. references baron-szabo, r.c. & steuber, t. (1996): korallen und rudisten aus dem apt im tertiären flysch des parnassgebirges bei delphi–arachowa (mittelgriechenland) [aptian corals and rudists in tertiary flysch of parnass mountains near delphi–arachowa (central greece) – in german].– berliner geowiss. abhandl., e18, 3–75. blanchet, r. (1975): de l’adriatique au bassin pannonique – essai d’un modèle de chaîne alpine [from adriatic to pannonian – a proposed model for the alpine chain – in french].– mém. soc. géol. france, 53 (120), 1–172. borgomano, j., masse, j.-p. & al maskiry, s. (2002): the lower aptian shuaiba carbonate outcrops in jebel akhdar, northern oman: impact on static modeling for shuaiba petroleum reservoirs.– am. assoc. petrol. geol. bull., 86/9, 1513–1529. buser, s. (1989): development of the dinaric and the julian carbonate platforms and of the intermediate slovenian basin (nw yugoslavia).– mem. soc. geol. ital., 40 (1987), 313–320. charvet, j. (1970): aperçu géologique des dinarides aux environs du méridien de sarajevo [geological outline of dinarides in the area south of sarajevo – in french].– bull. soc. géol. de france (7), 12/6, 986–1002. chikhi aouimeur, f. (1983): etude paléontologique de quelques rudistes de l’aptien supérieur du djebel ouenza (algerie nord-orientale) [palaeontological study of some upper aptian rudists of djebel ouenza (northeastern algeria) – in french].– géologie méditerranéenne, 10, 33–48. chartrousse, a. (1998): les caprinidae (rudistes) du cretace inférieur [lower cretaceous caprinidae (rudists) – in french].– unpubl. phd thesis, université de provence, marseille, 289 p. cousin, m. (1973): le sillon slovène: les formation triasiques, jurassique et neocomiennes au nord-est de tolmin (slovénie occidentale, alpes meridionales) et leur affinites dinariques [the slovenian trough: triassic, jurassic and neocomian formations northeast of tolmin (western slovenia, southern alps) and their dinaric affinities – in french].– bull. soc. géol. france (7), 15, 326–339. cvetko-tešović, b., bucković, d., jelaska, v., gušić, i. & korbar, t. (2003): lower cretaceous platform deposits of mt. svilaja.– in: vlahović, i. & tišljar, j. (eds.): evolution of depositional environments from the palaeozoic to the quaternary in the karst dinarides and the pannonian basin. excursion guidebook, 22nd ias meeting of sedimentology – opatija, croatia, 83–92, zagreb. di stefano, g. (1889): studi stratigrafici e paleontologici sui sistema cretaceo della sicilia. 1. gli strati con caprotina di termini-imerese [stratigraphical and palaeontological study of the cretaceous system of sicily. 1. deposits with caprotina of tremini-imerese – in italian].– atti della reale accademia di scienze, lettere e belle arte di palermo, 10, 44 p. d’orbigny, c. (1847): considérations zoologiques et géologiques sur les brachiopodes ou palliobranches [zoological and geological considerations on brachiopods and palliobranches – in french].– compt. rend. hebd. séanc. acad. scien., 25/7, 266–269. douville, h. (1915): les requieniides et leur evolution [requieniiids and their evolution – in french].– bull. soc. géol. france, 4/14, 383–389. dragičević, i. & velić, i. (2002): the northeastern margin of the adriatic carbonate platform.– geol. croat., 55/2, 185–232. fliert, j. van de (1952): liste des rudistes du crétacé du constantinois [list of cretaceous rudists of the constantine area – in french].– in: deleau, p. (ed.): les pays constantinois. xixeme congrès géologique international alger, monographies regionales, 13, 47–52. gray, j.e. (1848): on the arrangement of the brachiopoda.– annals and magazine of natural history, 2, 435–440. 130 geologia croatica 57/2 131masse et al.: lower aptian rudist faunas (bivalvia, hippuritoidea) from croatia hughes, g.w. (1998): middle east aptian rudist–foraminiferal–algal associations and their possible modern arabian gulf analogue.– geobios, mem. spec., 22,147–158. jelaska, v. (1987): paleoambijentalna dinamika sjeveroistočnog rubnog prostora vanjskih dinarida u juri i kredi (jurassic and cretaceous paleoenvironmental dynamics of the northeastern margin of the outer dinarides).– geol. vjesnik, 40, 195–216. kühn, o. (1932): rudistae. fossilium catalogus, i: animalia [rudistae. fossil catalogue, i: animals – in german].– pars 54. gustav feller, neubrandenburg, 200 p. masse, j.p. (1985): paléobiogeographie des rudistes du domaine peri-méditerranéen a l’aptien inférieur [palaeobiogeography of early aptian rudists in the perimediterranean domain – in french].– bull. soc. géol. france, 8/5, 715–721. masse, j.p. (1992): les rudistes de l’aptien inférieur d’italie continentale: aspects systematiques, stratigraphiques et paléobiogeographiques [lower aptian rudists of continental italy: systematic, stratigraphic and palaeobiogeographic aspects – in french].– geol. romana, 28, 243–260. masse, j.p. (1993): systematique, stratigraphie et paléogeographie du genre lovetchenia (requieniidae) du crétacé inférieur méditerranéen [taxonomy, stratigraphy and palaeogeography of the genus lovetchenia (requieniidae) of the mediterranean lower cretaceous – in french].– geobios, 26/6, 699–708. masse, j.p. (1996): lower cretaceous rudist biostratigraphy of southern france, a reference for mesogean correlations.– revista mexicana ciencias geologicas, 12/2, 236–256. masse, j.p., bellion, y., benkhelil, j., boulin, j., cornee, j.j., decourt, j., guiraud, r., mascle, g., poisson, a., ricou, l.e. & sandulescu, m. (1993): lower aptian 114–112 ma.– in: dercourt, j., ricou, l.e. & vrielynck, b. (eds.): atlas tethys, palaeoenvironmental maps, maps. beicip–franlab, rueil malmaison. masse, j.p., arias, c. & vilas, l. (1998a): lower cretaceous rudist faunas of southeast spain: an overview.– geobios, mem. spec., 22, 193–210. masse, j.p., chartrousse, a. & borgomano, j. (1998b): the lower cretaceous (upper barremian–lower aptian) caprinid rudists from northern oman.– geobios, mem. spec., 22 , 211–223. masse, j.p., gallo maresca, m. & luperto-sinni, e. (1998c): albian rudist faunas from southern italy: taxonomic, biostratigraphic and palaeobiogeographic aspects.– geobios, 31, 47–59. masse, j.p., gourrat, c., orbette, d. & schmuck, d. (1998d): hauterivian rudist faunas of southern jura (france).– geobios, mem. spec., 22, 225–233. masse, j.p., özer, s. & fenerci, m. (in press): upper barremian–lower aptian rudist faunas from the western black sea region (turkey).– cour. forsch. inst. seckenberg. masse, j.p., skelton, p.w. & slišković, t. (1984): glossomyophorus costatus nov.gen. nov.sp., rudiste (caprotinidae) nouveau de l’aptien du domaine méditerranéen central et oriental [glossomyophorus costatus nov.gen. nov.sp., new aptian rudist (caprotinidae) of central and eastern mediterranean – in french].– geobios, 17, 723–732. matheron, p. (1842): catalogue méthodique et descriptif des corps organisés fossiles du département des bouchesdu-rhone et lieux circonvoisins [catalogue of fossil organisms of the bouches-du-rhone and neighbouring areas – in french].– carnaud fils, marseille, 269 p. munier chalmas, h. (1873): prodrome d’une classification des rudistes [introduction to rudist classification – in french].– journal de conchyliologie, 3, 71–75. newell, n.d. (1965): classification of the bivalvia.– american museum novitates, 2006, 1–25. pamić, j., gušić, i. & jelaska, v. (1998): geodynamic evolution of the central dinarides.– tectonophysics, 297, 251–268. paquier, v. (1903): les rudistes urgoniens. premiere partie [urgonian rudists. part one. – in french].– mém. soc. géol. france, paléontologie, 11, 1–46. paquier, v. (1905): les rudistes urgoniens. ii serie inverse [urgonian rudists. ii “serie inverse” – in french].– mém. soc. géol. france, 29/13, 47–102. paquier, v. (1908): sur les rudistes de l’urgonien de serbie [on urgonian rudists of serbia – in french].– mém. soc. géol. france, 8, 1–108. pleničar, m. & buser, s. (1967): the cretaceous macrofauna in the western part of the trnovski gozd.– geologija, 10, 147–159, ljubljana. polšak, a. (1970): offneria rhodanica du cretace inferieur de la lika en croatie [offneria rhodanica from the lower cretaceous of lika in croatia – in french].– geol. vjesnik, 23, 145–149. sartorio, d. (1986): caprinid patch reef in the cansiglio inner platform carbonate sequence (southern alps): a record of the earliest aptian transgression.– riv. ital. paleont. strat., 92, 383–400. sartorio, d. (1987): reef and open episodes on a carbonate platform margin from malm to cenomanian: the cansiglio example (southern alps).– mem. soc. geol. ital., 40, 91–97. skelton, p.w. (1978): the evolution of functional design in rudists (hippuritacea) and its taxonomic implications.– in: yonge, c.m. & thompson, t.e. (eds.): evolutionary systematics of bivalve molluscs. philosophical transactions royal society, london, b248, 305–318. skelton, p.w. & masse, j.p. (2000): synoptic guide to lower cretaceous rudist bivalves of arabia. middle east models of jurassic–cretaceous carbonate systems.– soc. econ. paleont. miner., spec. publ., 69, 89–99. tišljar, j. (1978): oncolites and stromatolites in lower cretaceous carbonate sediments in istria (croatia, yugoslavia).– geol. vjesnik, 30/2, 363–382. tišljar, j., vlahović, i., matičec, d. & velić, i. (1995): platformni facijesi od gornjeg titona do gornjega alba u zapadnoj istri i prijelaz u tempestitne, klinoformne i rudistne biolititne facijese donjega cenomana u južnoj istri 130 geologia croatica 57/2 131masse et al.: lower aptian rudist faunas (bivalvia, hippuritoidea) from croatia (ekskurzija b) platform facies from the upper tithonian to upper albian in western istria and transition into tempestite, clinoform and rudist biolithite facies of the lower cenomanian in southern istria (excursion b).– in: vlahović, i. & velić, i. (eds.): 1. hrvatski geološki kongres (first croatian geological congress), vodič ekskurzija (excursion guide-book), 67–110, zagreb. toula, f. (1902): geologische untersuchungen im östlichen balkan und in anderen theilen von bulgarien und ostrumelein [geological investigations in the eastern balkans and in other parts of bulgaria and east romania – in german].– denkschrifen der kaiserlichen akademie der wissenschaften, mathematisch-naturwissenschaftliche klasse, 59, 409–478. turnšek, d., pleničar, m. & šribar, lj. (1992): lower cretaceous fauna from slovenski vrh near kočevje (south slovenia).– razprave iv razreda sazu, 33, 1–14, ljubljana. velić, i. (1988): lower cretaceous benthic foraminiferal biostratigraphy of the shallow-water carbonates of the dinarides.– revue de paléobiologie, vol. spéc. 2 (benthos ‘86), 467–475, genève. velić, i. & hvala, m. (2002): istrian rudist limestones as architectural-building stone.– in: vlahović, i. & korbar, t. (eds.): abstracts and excursion guidebook. 6th international congress on rudists, rovinj, 141, zagreb. velić, i. & sokač, b. (1978): biostratigraphic analysis of the jurassic and lower cretaceous in the wider region of ogulin, central croatia.– geol. vjesnik, 30, 309–337. velić, i. & sokač, b. (1979): younger lower cretaceous and lower cenomanian. excursion c: karlovac–ogulin of central croatia.– 16th european micropaleontological colloquium. ljubljana, 147–156. velić, i. & sokač, b. (1981): osnovna geološka karta sfrj 1:100.000, list ogulin l 33–103 (basic geological map of sfry 1:100.000, ogulin sheet).– institut za geološka istraživanja zagreb (1976), savezni geološki institut, beograd. velić, i. & tišljar, j. (1987): biostratigraphic and sedimentologic characteristics of the lower cretaceous deposits of the veli brijun island and comparison with the corresponding deposits in sw istria (western croatia, yugoslavia).– geol. vjesnik, 40, 149–168. velić, i., tišljar, j. & sokač, b. (1989): the variability of thicknesses of the barremian, aptian and albian carbonates as a consequence of changing depositional environments and emersion in western istria (croatia, yugoslavia).– mem. soc. geol. ital., 40, 209–218. velić, i., matičec, d., vlahović, i. & tišljar, j. (1995): stratigrafski slijed jurskih i donjokrednih karbonata (bat–gornji alb) u zapadnoj istri (ekskurzija a) (stratigraphic succession of jurassic and lower cretaceous carbonates (bathonian–upper albian) in western istria (excursion a)).– in: vlahović, i. & velić, i. (eds.): 1. hrvatski geološki kongres (first croatian geological congress), vodič ekskurzija (excursion guidebook), 31–66, zagreb. velić, i., tišljar, j., vlahović, i., matičec, d., korbar, t., moro, a. & ćosović, v. (2002): geological evolution of istria (nw part of the adriatic carbonate platform, croatia).– in: vlahović, i. & korbar, t. (eds.): abstracts and excursion guidebook. 6th international congress on rudists, rovinj, 83–93, zagreb. vlahović, i. (1999): karbonatni facijesi plitkovodnih taložnih sustava od kimeridža do gornjega alba u zapadnoj istri (carbonate facies of shallow water depositional systems from kimmeridgian to the upper albian in western istria – in croatian with english summary).– unpubl. phd thesis, university of zagreb, 327 p. vlahović, i., tišljar, j., velić, i., matičec, d., skelton, p.w., moro, a. & korbar, t. (2002): aptian deposits with requieniids below a late aptian–early albian regional emersion surface (kanfanar and dvigrad, central istria).– in: vlahović, i. & korbar, t. (eds.): abstracts and excursion guidebook. 6th international congress on rudists, rovinj, 95–100, zagreb. manuscript received february 17, 2004. revised manuscript accepted november 08, 2004. 132 geologia croatica 57/2 133 plate i requienia? zlatarskii, sections from kanfanar quarry. 1–2 anterior–posterior cross sections of bivalve specimens showing the lamellar anterior side, convex upper valve, the body cavity of which is separated from the lower part by a well defined cardinal platform. 3 ibidem. upper valve absent. 4–5 dorso–ventral cross sections of bivalve specimens showing the body cavity of the upper valve and the cardinal platform. 6–7 field photographs showing the strong anterior–posterior asymmetry and the ventral carina. 132 geologia croatica 57/2 133masse et al. plate i p 1 3 6 l cm a 7 134 geologia croatica 57/2 135 plate ii toucasia sp., sections from kanfanar quarry. 1 dorso–ventral cross section of a bivalve specimen showing the myocardinal characters. 2 transverse-oblique section showing the spirogyrate organisation of the lower valve and the posterior myophoral plate. 3 section close to fig. 2, myophoral elements not preserved. 4 tranverse oblique section of the lower valve showing the posterior myophoral plate. 5 transverse section of a lower valve showing the posterior myophoral plate. 6 transverse section of a lower valve showing the myocardinal elements. 134 geologia croatica 57/2 135masse et al. plate ii p 1 em a 136 geologia croatica 57/2 137 plate iii himeraelites sp., tounj. 1–2 transverse section of the lower valve and interpretation of the myocardinal features. 3–4 ibidem. notice the development of the inner formerly aragonitic shell, the calcitic, finely ribbed outer shell is partly preserved on specimen 1–2 (arrow). 136 geologia croatica 57/2 137masse et al. plate iii p p d l ,, , i ,_ ... ct ....... _ .... \ i /'" , i pt / l /l '" at i " i , i mp, i , , \ , , , , be , ', ma , a 2 -----, 1 em / , , ,et ....... 'i ' i i , 1_ .... ,\\ at \ ....... 1 'j \ i i i , impl , , \ , 4 , , i i' , ... '" i \ ---' rna' , , , , be a v v 138 geologia croatica 57/2 editorial 63-2.indd 127 � sustainability of the karst environment – dinaric karst and other karst regions � doi: 104154/gc.2010.08 geologia croatica 63/2 127 zagreb 2010 geologia croaticageologia croatica edi to rial dear readers, this issue 63/2 of geologia croatica is largely dedicated to the topic of karst, a theme we would like to include more often in our journal. besides the usual editor, geologia croatica also has a guest editor dr. ognjen bonacci. he has been appointed guest editor for this volume since he was the scientifi c organizer of the international interdisciplinary conference sustainability of the karst environment – dinaric karst and other karst regions, september 23−26, 2009. the conference was organized by the centre for karst gospić, and was held at the spectacular plitvice lakes (unesco world heritage site), croatia. the objective of this international conference was to provide theoretical and practical contributions to the concept of sustainable development in karst regions, with specifi c emphasis on the experiences from the dinaric karst region. karst landscapes, in which dissolution of bedrock by water is the dominant process, characterise almost 20% of the continents and more than a quarter of the earth’s population lives on or near karst areas (ford & williams, 2007). typical karst topography is essentially related to subterranean drainage and therefore geomorphology and hydrology are closely interrelated. the dinaric karst stretches the length of the eastern coast of the adriatic from the bay of trieste in the north to the drin river in the south. this karst area is some 600 km in length, and up to 200 km in width. however, karst landscapes are present in many parts of the world, but most of the time these areas are shaped by a multitude of processes. the karst landscape is a unique geological environment that extends not only on the surface but also underground, in a continuum of habitats and geo-ecosystems that still wait to be discovered and studied. more than eighty presentations and posters were presented at the conference, and nine papers originated from presentations at the conference dealing with geological themes. all contributions have passed the regular reviewing procedure, since this is an ordinary volume of our journal geologia croatica although it is predominantly devoted to karst issues. themes covered range from the evolution of caves, to understanding the hydrology of karst, and challenges to sustainability in karst terrains. sustainable development of surface and subterranean water resources in karst, and the overall karst environment has been threatened by current climate change and climate variability in combination with anthropogenic impacts. interdisciplinary studies are imperative in order to establish the possible consequences of such impacts and to fi nd practical solutions to protect karst systems. after the “karstic” papers, there are three other interesting contributions spanning palaeontological to geochemical issues. references ford, d. & williams, p. (2007): karst hydrogeology and geomorphology.– john wiley & sons ltd., chichester, u.k., 562 p. ognjen bonacci, guest editor and mladen juračić, editor-in-chief geologia croatica 63/2geologia croatica 128 geol. croat. zagreb 1997 the middle and upper permian deposits in gorski kotar: facts and misconceptions dunja aljinovic' and iasenka sremac' key words: chronostratigraphic division, pem10-trias­ sic boundary, permian, gorski kotar, croatia. abstract the frequent occurrence of sandstones and olher coarse-grained sedimentary rocks in gorski kolar indicates molasse type sedimenta­ lion as a consequence of the intensive erosion of all uplifted terrain in a tectonical ly active area. the indirect assumptions indicate thai the age of the gorski kolar palaeozoic complex, with the exception of a limited occurre nce of carboniferous clastic rocks, corresponds to the clastic trogkofel beds. i.e. (0 middle pcnnian. the absence of upper permian carbonate deposition in gorski kolar indicates an interrup­ tion in sedime ntat ion at the permo-triassic boundary, and a possible hiatus in the upper permian. in previous studies it was concluded that there is a co nt inuous transition from the permian (developed as the groden clastic facies) to the lower triassic shallow marine sedimen­ tary rocks, although no such transitions occur in either the neighbour­ in g areas (velcbit, slovenia) nor in thc widcr southern alps . the continuous lransition ex ists only in the carbonatc successions (upper permian dolomite in the velebit region and the beljerophonc forma­ tion in the alps). 1. introduction the stud ies that deal with the sedimentary rocks of the c1astie facies within the palaeozoic complex of gorski kotar, inevitably encounter the problem of their agc whcrc they do not contain fossils or any intercala­ tion of fossiliferous limestone. in general, the strati­ graphic difterentiation of clastic palaeozoic sedimenta­ ry rocks from gorski kotar is complicated due to the general absence of fossils in the clastic rocks, the poor preservation of ammonite fragments in black shales, poor preservation of fossils in the limestone intercala­ tions, and also due to the extremely intensive tectonics in the region and the absence of any lithostratigraphic i roacu]ty of mining, geology and petrolelllll engineering, university of zagreb, pierottijeva 6, hr-l 0000 zagreb, croatia. 2 departmcllt of geotogy and palaeontology, faculty of science, university of zagreb, ulica kralja zvonimira 8, hr-loooo zagreb, croatia. marker. these are the reasons why chronostratigraphic determination of the palaeozoic sedimentary rock com­ plex is ambiguous. the coarse-grained clastic rocks are considered the youngest facies in the perm ian succes­ sion. they are usually termed as "groden c1astites", "clastic rocks of the groden type" or as "deposits that correspond to groden beds". the aim of this paper is to discuss the ages attributed to these "groden clastic rocks" by various authors and to present differing and often opposing ideas about the age of the palaeozoic complex. also the intention is to compare the gorski kotar palaeozoic with the studied and described palaeo­ zoic depos its in the neighbouring areas, and to contem­ plate the justification of the assumption or a continuous sedimentation from the permian to the lower triassic. 2. review of previous studies previous studies of palaeozoic rocks in the gorski kotar region have been aimed mainly towards the dif­ ferentiation of the principal rock types, their mapping, and the description of mapped units which are some­ times termed as facies (fig. i). in papers dating back to the end of the last century and the beginning of this century, various stratigraphic interpretations have been given for the gorski kotar palaeozoic complex, with the majori ty dating it as car­ boniferous (foetterle, 1855; hauer, 1868). more recent data about the gorski kotar palaeozoic arc presented in papers by salopek (1949a, b, 1960, 1961 ). during studies of the gorski kotar region salopek defined the principal upper palaeozoic sedime~tary rock units in the vicinity of mrzla vodica and crni lug (salopek, 1949a, 1960) and gerovo and trsce (sal­ opek. 1 949b, 1961) · figs. 1 & 2, and fig. 1 in sre­ mac & aljinovic (1997 . this vol) the principal sedimentary rock units were defined according to their lithology and mode of occurrence. this paper was presented at the scientific meeting dedicated to the 80th anniversary of the life of professor milan herak, held on march 5th, 1997 in zagreb iiiiil miiil o kocevje • iookm ... bosnia and nerzegovina • 0 n a fig. i simplified geological map of gorski kolar (modified after sa v ie & dozet, 1984). legend: i) carbon i ferous s'li1dsl.o ncs; 2) permian sedimentary complex: 3) scythian clastic rocks and dol omit es; 4) upper triassic do lomite ("haupldolomic') ; 5) jurassic carbonates ; 6) cre­ taceous limes tones ; 7) eocene breccia; 8) alluvium; 9) mai n localiti es. apart from a limited occurrence of upper carbonif· e rou s trit ic it cs sandstones on the ba nks of the kriz stream, sa lopek (i 949a, 1960) regarded the major part of the palaeozoic complex 10 be of pcmlian age. in this complex he differentiated the follo wing units: ( i) the "clayey schists" in alternation with dark sandstones (pgs), (2) the "c layey schi sts" (g5), and (3) the gray sand stones cps) which occur separately in the broader region. as a separa te unit (4) the author di stinguished also dark fossiliferous limestone (cv). this type of rock frequently accompan ies the "clayey schists" in alterna­ ti on w ith dark sandsto ne (pgs), and is also frequently inte rcalated with in the "clayey schists" (g5). within the fo ss ilife rous lim estone, a fauna was discove red that corresponds to that of the rattendorf beds. the ensuing units (5) are the trogkofel limestone which diffe rs in the presence of inte rsecting calc ite ve ins, the occur­ rence of numerous calcite and quartz pebbles, and rarer occurrences of fusulinids than in the prev ious limestone types . a distinct (6) type termed the "cephalopod cla­ yey schi sts" occurs in alternalion with sandstone in a restricted area around mrzla vodica. al so he d is tin ­ guishcd a different type of limestonc (7) from the previ­ ous ones, the " limestone with lithoni ae". according to salopek (1960) these se ven rock types contain enough fo ss il data to co nfirm a lower aljinovic & srcmac; '!lie middle and upper permian deposits in gorski kotar. .. and middle permian age (which was later verified by milanovic & kochansky-devide, 1968, and kochansky-devide, 1973) fig. 2. after these conclusions salopek (1960) described an cighth independent rock type (8), the groden conglomerates, and (9) gray to light gray groden sandstone (pcp). salo pek (1949b) outlined the upper palaeozoic in the vicinity of gerovo and trsce (figs. i & 2) and differentiated five rock types, i.e. facies which corre­ spond to those near mrzla vodiea. however, he noticed that " the most striking difference is the lack of signifi­ cant limestone intercalations, which are present in all upper palaeozoic cross sections adjacent to mrzla vod­ iea, whcre they werc the principal bearers of a fusulinid and brachiopod fauna" (salopek, 1949b, p. 194). later, salopek (1949a, b, 1960) also attempted to solve the stratig raphic questions connectcd with the palaeozoic complex (fig. 2). his conclusion s were as follows: "the fus ulinid sandstone undoubtedly proves the very limited occurrence of the upper carboniferous in the palaeozoic rocks near mrzla vodica. according to thc fauna detcrmined they belong to the ural ien. the basis for the permian differentiation was the determina­ tion of ammonites found in the "black schists" by vogl ( 191 3) as bcing related to the sossio fauna type. the sossio beds are represented by a goniatite cephalo­ pod fauna. these laycrs arc confi ned to the upper part of the succession of clayey schist in alternation wi th dark sandstones (pgs). therefore, "the clayey sch ists and sandsto nes" (pgs) reach and enclose the middle permian sossio beds. the sporadic dark limestone intercalation with fusu lini ds contain s a scant fauna, which indicates the rattendorf and in part maybe the trogkofel beds. a gradual transition ex ists from the "pgs" into the groden deposit s which consist of con­ glomerates and sandstone. the upper permian bcllero­ phone facies is absent" (salopek, 1960, p. 128). although salopek does not stress it , it is obvious from his papers that the rocks cal led "groden conglom­ erates" and "groden sandstone" he associates with the rocks that , by ihe fo ss il co nt ent , are att ached to the lower and middle pennian. so, hc concludes: "within the clayey schi sts and sandstones (pgs) in their upper part sporad ically an intercalation of conglomerate can be found. this is the transit ion into the permian clastic series." however, he considers that the mentioned con­ glomerates occur in the upper part of that permian series, therefore they are sti ll confined to the middle permian (fi g. 2). the confirmat ion of this opin ion is found in the paper by salopek (1961, p. 245), where in the dcscri ption of palaeozoic rocks in the areas of smrecje, trsce and cabal' (fig. 1) he states the fo llow­ ing: "the typica l cephalopod schist facies does not occur in ihe gerovo-cabar palaeozoic, nevertheless on the basis or the significant "pgs" series, these deposits in the gerovo-cabar palaeozoic can be, together with overlyi ng sandstones and conglomerates, connected to the wordian (middl e permian) which was palaeonto­ logically determined near mrzla vodica." it is impor233 tant to stress that salopek tried to find the eq uivalent sedimentary rocks to those that he had previously stud­ ied (salopek , 1948), and that he associates the gors­ ki kotar palaeozoic development with the development of the palaeozoic in the velebit region (and not in the alps). from the desc ription of groden conglomerates in gorski kotar made by salopek which he claim ed to belong to the "upper pennian series" some later misin­ terpretations were inferred. according to some later citations (jurkoyic, 1959; ramoys & kochan­ sky-devide, 1965; susnjara & sinko vec, 1973) it is stated that upper permian groden clastic rocks exist, which is a total misinterpretation of conclu­ sions made by salopek. an accurate confirmation of the upper permian in gorski kotar documen ted by fo ssils has not been made. the problem whether upper permian rocks do or do not occur in gorski kotar, conscquently raises the ques­ tion of a continuous or di scontinuous transition at the permo-lower triassic boundary. the question of this contact was rai sed by scaynicar & susnjara (j 967 , p. 93) fig. 2, who determined that "at several places it is possible to observe a direct contact, and no clements indicat ing tran sg ression are visibl e, but an impression exists that there was a continuous succes­ sion. " these authors tried to solve th is problem wi th the aid of petrographic methods. these methods revea led only thc quant itati ve differences in associa tions of heavy minera ls between the palaeozoic clastic rocks (for which it is claimed that they are the transitional lith ofac ies) and the triassic clastic rocks. the differ­ ence is primarily manifested through the content or chlori te and apatite, the quant ity of which rises from the permian sedimentary rocks and is significantly en ha­ nced in thc lower triassic sedimentary rocks. thc sa­ me authors, on the basis of these ana lyses emphas ise the tight connection between the sedimentary rocks which are presumably upper permian with the lower triassic rocks. the authors them selves conclude that "furth er field and analyt ical st udies are necessary in order to solve the relation ship bctwcen thc upper pal­ aeozoic and the lowcr triassic". raffaelll & sca­ vnlcar (1968, p. 25) state that " the coarse-grained petromictic conglomerates and sandstone, according to their petrographic composition and their stratigraphic position, match the groden deposits from the can~ian alps". these authors also state their doubt: " ... lhat it is not kn own whether the whol e upper permian in th e gorski kotar region is developcd as a clastic facies or that equivalents of the bellerephon limestone might ex ist. " the authors of the explanatory notes for the del­ nice sheet of the basic geological map sa vic & dozet (1985), state that the gorski kotar pa laeozoic complex contains upper carboniferous deposits (c3) as well as lower and middle permian deposits. the frequent occurrence of coarse grained sedimen­ tary rocks and sandstones (groden facies ) herak & !1 " s: "0 tv c »;::;'r.n en 0 q u) -, ;::; "' 3 ~ if2: so o· ~ .s ;!; ~ ~ '0 9.~. 00 ::j ~ 001'::-0 ':-' ::::!. ::::d. ~. po: 2.. o c ~3 < 0 o -~ zg -", 3:~ " ~~ < ~. n ~ ;::;. ::: [~ q ;<; -~ " 5' ~ ~. ~~ ",3 ro ;;~ z -. 0 "0 mo ~~ "' _. "'" no :c ~ o . " 0 0;: co "" --2-. \0 c. 000 0,0 '"'. n ;:;: "'~ "'. en,=. " zo 0 "'3 ;! ~ ::.> (1) :-b; --~~ 000 00 < ~ 0 :>: ~. ;::: ~ ~ 0 scythian late permian middle permian early permian outer dinarids slovenia ortnek kocevje ~j]~~=~1 (ramovs 8. kochan· ~thian sky-oevide,i965: ramoys. 1968: italian research group. (germovsek, 1962: ramov$ 8koch~nsky­ devioe.1965) dzhulfian abadehian capitan ian wordian artinskian sakmarian asselian 1985: massari 81 al., 1988) trste (aljinovic, 1997) (1961) ~ limeslone breccia r=1 ~ sandy mk:aceous shale §:m ~ o _ conglomerale tabular grainstone iragments of reef limestone iimome and haematile fragments h:.:·.'·:·:::·:~::j sandstone pe l ~e sediments sha le gorski kotar salopek tttil (1960) l imestone w~h quaflz pebb les erm biocaicaren~e g7§j limestone bklcks f) ammonites <l> brach ipods ",crinokjs ¢ noral detr~us mrzla vodica (kochansky·devid~ . 1973) paralriliciles darvasites pseudofusuiifla aft , rakoveci robusroschwagerina schellvieni zellia ex gr. herilschi nankinela paraschwagerina ramovsia limes @ bioc lastic detritus w~h cortices q int raclasts arld pellets ~~:j~i~~t. 1968) d calc lnhite ___ unconform~y >taleral facies exchange velebit mt. ? ? (kochansky-devioe, 1979) (venica l scale modl!ied) sraffelasp yabeina sirtalis neoscllwagerina cra/tcumera eoverbekina salopeki scllwagerina camiolica zellia llerirsclli occkfentoscllwagenna ex/ensa pseudoscllwagerina exatl. a/pina lower triassic dolomites lower triassic shales dense, bedded dolom~es light-coloured saccharoidal dolomites middle-upper permian black limeslones dark-gray spolty limeslones trogkofe llimestones middle perm ian shales ko~na conglomerates w~h iimeslone pebbles permian quafl> conglomerates kosna basal breccia sandslones (gray. red. yell ow) ranendorf limestones c 8 ii " r § q u s , aljinovic & srelll:lc: tile middle and upper permian deposits in gorski kot:lr. .. tomic (1995) considered as molasse type sedimenta­ tion occurred in upper permian. since the studies published by salopek (1949a, b, 1960, 196 1), and the paper by sca vnicar & susnjara ( 1967), who on thc basis of petrologica l evidence regard the coarse-grained fac ies as the youn­ gest upper permian deposits, not a single paper has been publi shed that gives either new palacontological o r petro logica l ev idence or data that could be used to cla rify the problem of the upper permian in gorski kotar. nevertheless, a widespread idea that "upper per­ mian groden clastic rocks" ex ist, is expressed by ci ta­ ti ons made by var ious authors (susnjara & s in­ kov ec, 1973; cerina, 1986; palinkas & sre­ mac , 1989; palinkas et ai., 1993), although their studies did not deal with the stratigraphy of the rocks present. 3. discussion in the rather few papers that deal with the problems of the youngest palaeozoic sedimentary rocks in gorski kotar severa l inconsistent interpretations can be obscr­ vcd. firstly, therc is an inconsistency in the petrograph­ ic defini ti on of the you ngest faci es. as can be observed in the paper by scavnicar & susnjara (1967) it is asserted that in the boundary reg ion toward s the lower triass ic at the studied localities near su ha recina, podtisovac, zelin and trii(~e , sandstones occur which have the characteristics of transi tion rocks. due to their red colour they resemble the lower triassic sedimentary rocks. however, red sandstones also have grey equivalents. a year later raffaelli & scav­ nica r ( 1968, p. 25) determi ned that the "coarse­ grained petromiclic conglomerates and sandstones" are transition deposits and compared them with the groden type deposits from the carnian alps. sca vnicar et a l. 3 (p. 46) substantiatcd a fac ies differentiation, i.e. the ex istence of "coarse-grained and finc-grained conglom­ erates inserted between sandstones" which represcnl the " membe rs of the yo ungest palaeozoic clastic series". however, the same authors (p. 47) state that "occasion­ a ll y the terminating members are fine-grained mica­ ceous sandstone and silty-pelitic sedimentary rocks of a grey-purplish to a reddish colour which are lithological­ ly sim ilar to the lower triassic deposits at the trsce, podtisovac and suha recina localit ies". palinkas & s inkovec ( 1986) consider shale, si ltite and sand­ stone as the youn gest permian clastic sedi mentary rocks. pali nkas et al. (1993) adopted the opinion from earlier s tudics (sca vnicar & susnjara, 1967) about the upper permian greyish-green and pur­ pli sh-g rey fine -grained s iltite and pelite which are in 3 sea vntcar, b .. sokac, b. & velie, i. (1972): pateogeogratija trijnsa ii podrucju vanjskih dinarida, i gorski kotar.unpub­ li shed report. archive of the institute of geology, zagreb. 235 eonfom1able succession with the lower triassic periti­ dal basal dolomites. however, palinkas et al. ( 1993) stated, that " according to a cross sect ion near lokve and skolski brijeg, the upper permian clastics are rep­ resented by black shales and sands tones thc layers of wh ich are several centimetres thi ck. red shales and "groden " type sandstone equivalent s und erli e these deposits". from the above statements it is obv ious that the answer to "what underlies the lower triass ic sedimen­ tary rocks" is ambiguous. red and grey conglomerates and sandstone are present below the lower triass ic rocks (scavnicar & susnjara, 1967; raffa­ elli & sca vnicar, 1968), also red coloured con­ glomerates, sandstone and pelitic rocks (sca vnicar et a1 3 ; palinkas & sinkovec, 1986), as well as black shale and sandstone (palinkas ct ai. , 1993). no single facies can be inferred as the sole uppcr per­ mian member, excluding therefore the lithological crite­ rion as being satisfactory for stratigraphic evaluation. it is apparent that the colours are also not characteristic. raffaelli & scavnicar (1968) detcrmined that there are red groden clastic rocks that also have g rey cquivalents. although scavnica r et ai. ' concluded that the transi tion deposits are red and can be mistaken for lower triassic, palinkas ct a l. ( 1993) found black shale and sandstone in contact with the overlyi ng dolomites, and in boreholes bluish and gray sandstones were detcnnined. since salopek (1949a, b, 1960) interpreted the faci es that the above mentioned au thors prese nt as the upermost part of the upper pennian sequence, as mid­ dle permian, it is possible that these are the same facies but their age was interpreted differently. in the longest encou ntered cross section throu gh palaeozoic sedimentary rocks (approximately 1 so m) situated in thc valley of the sokol ica stream ncar trsce (salopek, 1961; aljinovic, 1997) figs. i & 2, it is possible to distinguish several facies of coarse-grai­ ned quartz conglomerates and sandstone. these facies are laterall y contemporaneous (all inov ic, 1997). moreover, in the uppermost part of the cross section , black shales occur in alternation wit h sandsto ne con ­ taining large quantities of plant dctritus. ft is indis­ putable that the conglomerate facies a llernating with shales and sandstones form a unique genetic sequence and are interpreted as facies of a fan delt a compl ex (aljinovic, 1997). it is important to stress that salopek (1961 ) bcli­ eved that this palaeozoic sequence was fo lded during the variscan orogeny which he represents with a sketch (p. 248, fig. 4). very close to this outcrop, i.e. in the sokolska slije­ na cross section, sea vnicar et ai. 3 determined a continuous transition over the palaeozoic/lower trias­ sic boundary in the following way: "the starting point for the study was located in grey dolomites, and the outcrops of upper palaeozoic clayey schi sts and sand­ stone occur some 10 m below them". the rea l contact 236 therefore is absent, but thc effect of a continuous transi­ tion remains, probably due to the lack of any angular discordance. the lack of any angular discordance was, it seems, the principal criterion indicating continuous deposit ion between the palaeozoic and lower triassic. some authors have questioned the validity of the char­ acter of this contact. sca vnicar & susnjara (1967, p. 93), and scavnicar et al 3 state that there are no clements of lower triassic transgressive rela­ tionships, nor an angular discordance, "but an impres­ sion exists that there is a continuous sequence and a normal transition". in their report scavnicar et a1. 3 conclude that continuous deposition exists on the basis of characteristics or 6 studied cross sections across the pal aeozoic/lower triass ic boundary. on four of the studied cross sect ions the contact was covered so that direct observations were not possible. the same authors state that the character of the transition is gradual, but, nevertheless, in their conclusion claim that the contact with the palaeozoic is marked by an abrupt appearance of lower triassic do lomites accompanied by variable amounts of barite. the following question remains: if the change from palaeozo ic sedimentation to lower triassic sedimentation is expressed as an abrupt change from a principally clastic deposition (sandstone, shale, red conglomerates, or black shale and sandstone) into oolitic lightl y coloured dolomites, is the presumption of continuous sedimentation justified? perhaps less so, as the character of thc contact cannot frequently be obser­ vcd duc to the surface cover and tectonics. it has been recogni zed that a few metres of a cross section can con­ tai n whole geological periods (e.g. the upper aptian and lower albian in istria · vellc et ai., 1995). if a continuou s transition ex ists, and it can only be docu­ mented petrographically, it is then necessary to show the cross section in detail accompanied by almost con­ tinuous sampling, in order to determine the changing character of the petrographic parameters. the attempt to dctermine the transi tional deposits, i.e. the character of the palaeozoic/lower triassic tran­ sit ion by the ana lys is of the heavy mineral fraction (scavnicar & susnjara, 1967) seems to be co· mpletely justified. the difference is mainly expressed in the quantity of apatite and chlorite in the rocks. the rocks that were determined as upper permian tran si­ tional rocks have higher quantities of apatite and chlo­ rite than the underl ying palaeozoic rocks, and are simi­ lar to the lower triassic sedimentary rocks. however, elevated quantities of apatite and chlorite as the only differentiating parameter between palaeozoic rocks and lower triass ic rocks was di sputed by the discovery of apatite and chlorite as the main mineral components in the heavy mineral fractions in succession that were doc­ umented as middle permian (jelaska & prohic, 1982). thcreforc, these middle perm ian sedimentary rocks, due to the elevated quantities of apati te and chlo­ ritc have the character of transition deposi ts towards lower triassic. it should be noted that the lower per­ mian sedimentary rocks from the alps also contain geologia cro:llica 50(2 apatite and chlorite in the heavy mineral fraction (krainer, 1993, p. 546, fig. 9). in the light of these questions and inconsistancics, an open dilemma remains as to which criterion to use for age determination of the unfoss iliferou s clastic facies, i.e. how to interpret the transitional nature of the palaeozoic/lower triassic boundary. with this objec­ tive in mind it is necessary to review the definitions of palaeozoic and lower triassic successions in adjacent areas and present som e of the more recent develop­ ments that deal with the problems of simil ar lithofacies. 3.1. geological setting of palaeozoic and lower triassic rocks in adjacent regions (velebit and the slovenian part of the outer dinarids) the geographical posi tion of the gorski kotar, bet· ween the velebit palaeozoic complex to ~he east, and thc slovcnian palaeozoic to the west (fi gs . [ & 2), necessarily imposes the need for comparison with these areas both in the lithological and biostratigraphical sense. revealing the lithostratigraphica l problems in gorski kotar would provide the answer to the problem of the "miss ing link". this would not only be of local importance but would also contribute to the studies that deal with global events within the palaeozoic. the palaeozoic sedimentary sequ ence in velebit (fig. 2) was described in detail and biostratigraphically docum ented by salopek (1948 ), kochansky· devide (1965, 1982), sremac (1991), and tis· ljar et al. (1991 ). the permian deposits unconfor· mably overlie carboniferous deposits. they commence with limestone containing schwagerina and pseu­ doschwagerina, which are equivalent to the rattendorf beds that occur in the alps. the middle rattendorf beds arc cspecially well developed (sandy clays wi th shale intercalation granzlandbanke) with fu su linids of the zellia· type, quasiftlsldina nimia koci-iansky·dev· ide, neospirifer (kochansky.devide, 1982) and the problcmati ca ramovsia limes kochansky · devide. the kosna beds consist of coarse -grained conglomerates which often contain limestone pebbles that rangc from moscovian to upper assel ian (koch· ansky ·devide ct ai. , 1982) . apmt from these extra· ordinary mottled limestone conglomerates, the kosna series also includes fine-grained quartz conglomerate and also red, yellow and grey pyritic sandstone (raf· faelli & scavnicar, 1968) which are usually found in the basal part together with the breccias (salopek, 1942). limestones containing darvasiles, pseudoschwagerina and algae (koci-iansky · dev· ide, 1973) are rarely found in this series. the kosna series is considered to be the continuation of the clastic trogkofel beds deposits from slovenia, which form a dominanlly carbonate limestone evol ution in the alps, passing gradually in the east into a more claycy-sandy­ conglomerate type of sedimentation (kochansky· devide, 1982). aljinovic & srclli;lc; '111e middle ;111<1 upper pcnni:1i1 dci)()sils in gorski ko[<l r ... the middle and upper permian deposits consist of dolomites and limestones which conformably overlie the red kosna-sands toncs (kochansky -deyide, [982). occasionally it is possible to observe thc transi­ tion from the red sandstonc into the so-called first zone of black limestone (the zone with eo\'erbekiflo sa/opeki kocbansky-deyide). the rirst zone limestone contains oi'l/loceras and the large gastropods p/atys­ fall/a indiei lflll waagen and bel/erop/1011 cl jolle­ simj/ls koninck, and also an extraordinary microfau­ na of the eoverheekilla -spliaerillina and sta.lfelfa-type (kocbansky-deyide, 1982). the narrow lime­ stone zone is overlain by a succession (up to 300 m thi ck) of dark g rny dolomite, sometimes filled with waagenophylllllll (noll indiculll), mi:zia, eol'crbeekilla, swffella exposed sections, and occassionalty with neo­ schwagerilla. the second zonc of black limcstonc (t hc neosch­ wagerina craticulifera zonc) is most abundant in macro­ ross il s, among whi ch over 45 brachiopod genera were de te rmined (s remac , 1991) toge ther wi th the aber­ rant lamell ibranehiata tall eliilltongia ogulineci koch­ ansky -d eyide (kochansky-deyide, 1978). in the uppe r permi an from yel ebit , only carbonate beds were deposited as follows: i) subtidal to intertidal rll slliinid grainstone-packstone limestones, 2) e,1fly dia­ genc tic s upratidal dolomites, 3) black o rganic rich shales which alternate with bioclasti c packstones/grain­ stones, 4) supratidal dolomites with red shale intc rcala­ tion, (tislj ar et ai., 1991). the upper permi an depo­ si tion the refore occurred in a shallow marine, supratidal to inte rtidal environment , in locally isolated lagoons or bays rich in organic mud (,j'lslja r et al., op. cit.). the transition into the lower triassic is characteri sed by a morc frequent alt e rnation of dolomite and shale. the dense, so called bollnd ;:uy wcll bedded grey dolomite is poor in foss ils, but nevertheless it contains permian microforaminifcra and gymnocodiacea up to the bound­ ary with the werfen slightly sandy yellowish dolomites (sa lopek , 1942, 1948; ramovs & kochan­ skydevide, 198 1; t islja r et ai., 199 1). the lower palaeozoic of the siovenian outer dina­ rides outcrops mainly in dolenj ska and nca r kocevje (fig. 1). this compl ex ex tends across the rivers kupa and cabranka into croatia . the palaeozoic succession ncar ortnek (dolenjska) corresponds to the c last ic faci­ es of the trogko fe l beds and can be d ifferentiated into three main fac ies types which alternate both vcrtically and laterally (ramoys & kochansky-devide, 1965; ramov s, 1968) fig. 2. accord ing to these authors it was possible that the clast ic deposition com­ mcnccd in this a rea even in the lower permian and con tinued into the middl e permian. the whole palaeo­ zo ic co mpl ex in thi s a rea is approximate ly 2,000 m thick (ramoys, 1968) and is a coherent lithostrati­ graphic unit. the lower pan of thi s unit is represented by quartz conglomerates and quartz sandstone (fig. 2) . the con­ g lomerates are usuall y grey and only occasionally red237 dish as a consequence of the presence of haernatite. tn conglomerates with large pebbles, large blocks 01" limo­ nite can bc found (ramoy.s, \ 968). haematite rrag­ menl s and plant remnant s (according to this author) are an indication of shallow marine deposition fig. 2. grey fissile quartz sandstone that dominates the inte r­ mediate lithological unit occas ionally passes into g rey c lay sediments. within this unit , red varieties of sand­ stoncs with floral remnan ts can a lso be found , as well as black sandstonc with vein lets containing anthracite. it was a shallow marine cnvironmcnt suroundcd by a rich vege tated hinterland (ramoys, 1968). the upper part is dominat ed by grey schists which alt e rnate with layers of quartz sandstone which a lso contai ns abundant organic remnants (ramoy$, 1968). within the clayey sch ists lenses of different ree f lime­ stone types, limestone breccia or breccia-conglomerates occur (ramoys & kochansky-deylde, 1965; ramovs, 1968). according to the above aut hoi's (01' . cit.) thcse limestone int e rca lations partly reprcse nt ed small reefs that developed on the c layey sandy sea noor (fig. 2). erosion of these reefs produced the limestone brecc ia and conglomerates, wh ich, apart from limestone fragment s, also contai n sandstone clasts. a number of smaller reefs probably exi s tcd separated by dcepcr water, wherc clay and sand sediments were deposi 1ed (ramoys , 1968). a si milar lithologi cal development occurs ncar kocevje (the rcgion c losest to gorski kotar, fig. 2), but it docs no t contain limestone sedim cnts (ramoy$ , 1968). al so in the gerovo-cabar palaeozoic on the ot h­ e r side of the kupa rive r no lim estones we re found (salopek. i 949b, 1961 ; aljinoy1c, 1997). in the lcjrija region the equ ivalents of the trogkofcl limestone arc continentnl clas ti c facies and the upper permian is represented by gray marine dolomites of the zazar format ion (ramoys, 1968). the dcscription of the sediments near mrzla vodiea and (; rni lug given by salopek (1960) corresponds in many details to the success ions observed at ortnek, whil e the trsce-gerovo palaeozoic complex shows a sim il ari ty with the kocevje succession (fig. 2). the correlati on is mainly in the description of three lithofa­ c ies: quartz conglomerates, quartz sandstone and shale alte rnation, as wcll as the presence of li mestone inte rca­ lati ons. the vertical s liccess ion of any particular litho­ facies is not, however, the same in lhe descriptions giv­ cn by salopek (1960) and ramovs (1968). salo­ pek (op. cit.) presum es that in the upper part of thc sequence, conglomerates and sandstone occur, whil e ramoys (op. ei!.) places thcm in the basal part or the sequence. however, since ramovs also presumes that a late ral facies differentiation ex ists, il is possible that thc strict superposition order is miss ing. these differences can be int erpreted as lat e ral facies differentiation as mentioned by ramoy s ( 1965). the absence or limc­ stone intcrcalation in distinc t areas can be interpreted as a departure [rom the small reefs from where limestone clasts were derived. the groden c1asli c rocks as described by sca v­ nica r & susnjara ( 1967), raffaelli & sca­ vnica r ( 1968, fi g. 5) and palinkas el al. ( 1993) do not correspond, however, to the groden clastic rocks of neighbori ng vele bil and slovenian (idrija) areas, where this facies is considered to be middle pennian by salopek ( 1948) and ramovs (1968), bulla ihe groden c lastic rocks of the carnian alps. nevertheless, the ir features (colour and composition) could also cor­ res pond 10 ihe groden c lasli c rocks descr ibed by salopek ( 1949a, b, 1960, 1961) in ihe vicinily of mrzla vodica and crni lug, as well as ocravo, trsce and cabal', and are also similar to the lithofacies near onnck and koccvj c. this diversity hi ghli ght s the necess ity to anal yse the charac te ri stics of a broader region , i.c . the groden clastic rocks from the southern a lps (the sout hern alps are defined accord ing to flogel & faupl, 1987, as ihe soulhern pari of ihe easlem alps). 3.2. ti-ie geological framework of the palaeozoic and lower triassic rocks in ti-ie southern alps the geological framework of the palaeozoic sedi ­ mentary rocks from scvcral sites in the southern alps is presenled by ihe italian research group ( 1986, p. 37), and modified by massari et a l. (1988). in short , the fram ework characteristics are as foll ows: 'rhe resu lts of recent studies of this area are summa­ rized in ihe papers by sweet et al. (1992), raumer & neu bauer ( 1993) di slinguish ihe carboniferous­ permian sed im entary rocks and lowe r triass ic sedi­ mentary rocks, also te rmed lateto post-variscan sedi ­ mentary rocks, as two megacycles. the late-variscan and the post-vari scan movements commence in the sou thern and eastern alps in the upper carbonirerous (moscov ian/cantabrian ), which result ed in molasse type sed im entation which dom inated the lower sedi ­ menta ry cyc le, and pers isted until the lower perm ian (krainer , 1993). ii is separated from ihe upper sed i­ mentary cycle by a hiatus caused by the saa li an oro­ geni c movements. the upper cycle commenced in dif­ ferent areas at different times, but in general it cons.isls or (?)midd le-late permian and lower triassic sedi ­ ment a ry rocks. tectonic and climate changes are the main factors that divcrsified the sedimentation process­ es of ihese iwo cycles (schonla ub, 1993). the lower cyclc (upper carboniferous lower per­ mian) is characterized by the formation of intramol1lane basins fill ed wi th molasse type sediments. wi th in the lower cycle the transgressive-regressive clastic-carbon­ ate sedimentary rocks arc interpreted as a consequence of eustati c sea level oscillations, caused by glac iati on on gondwana (kratner, 1993). thi s in turn caused the climat e to change from humid to semi-arid during ihc middl e permian (sci-ionlaub, 1993). th e most important event which occurred in the permi an was the hiatus caused by the saalian orogenic movements which div ided the two cycles. the saalian movement s are characte rized by blockand wre nch­ faulting (krainer, 1993, p. 549). in ihe basal part of the upper cycle, in semi-arid cond itions conglomcrates, sandstone and mudstones are present as well as the " rcd bed type" sedimentary rocks deposited as periodic bra­ ided slreams and playa sedimenls (ass ereto cl ai., 1973; bugisch el ai., 1976). these sedimelllary rocks arc designated as the groden formation (according to krainer, 1993). in ihe carnian alps and ihe kara­ vanke, deposition commences w ith the tarvi ss io brec­ cia, and the groden formation consists of carbonatc shales and si ltitcs with thin dolomite interca lations, and sands tones that represent fluvial sed iment s, al luvial plain sediments, p layas and sha llow sea sedim ent s (buggisch el a i. , 1976; buggisch, 1978; ori & venturini, 1981; farabegoli cl ai. , 1986). dur­ ing the upper cycle (?m iddle-late permi an lower triassic) deposit ion is charac te ri zed by the te thyan transgression from the se towards the nw which cau­ sed a change in depositional type manifes ted in the fre­ quent a lternation of shallow marine sediment s with c lastic continental sediment types (g rodcn formation). the tectonic movements gradually aba te d urin g the upper cycle so the sedimentati on in the broader region became more homogenous and is characterized by shal­ low marine carbonate and evaporite sedimentation rep­ resented by the bellerophone format ion. in the juli an alps ncar bled marine depos ition is charac te ri zed by spongy-algal reefs (krainer , 1993). apart from weslern do lomil es (lombardy) where the "red bed" fluvial sediments of the verucano-lom­ bardo form ation are the equ ivalents of grodcn and belle rophone fo rmal ion (cass inis e l ai. , 1988) , ihe palaeozoic successions of all other regions te rm inate with the bellerophone formation. deposition of the uppcr cycle conti nuously proceeds with similar deposi­ tonal style to the lower scyt hi an whcre the upper boundary of the second cycle is traced. howevc r, the c limati c condit ions changed from arid to humid (brendner el ai., 1986) which caused ciraslic faunal changes. if the c last ic faci es of gorski kolar is co mpared wi th the groden formation from the carnian alps (raffaelli & scavnicar, 1968; pali n kas el a i. , 1993), it is presumed that at leas t some al tcrnation with the carbonate fac ies (equivalent of bellerophone fonnation) has to be expected as is the case with all the st udied profiles in the w ider region. if th is is not the case, can we expect an continuous transition into lower triass ic carbonate sedimentation? the deposi tion of the belle rophone formati o n is charac terized by a transgression in the north-western direel ion (broglio loriga & cassinis, 1992, p.79 , fig. 8.1.), exp laining why it pinc hes-ou t in that direc tion and passes into the co ntin ent a l fac ies. the deposit ion of the werfen, i.c. lower tri ass ic servino formation (represented by alternating c lasti c and car­ bonate sedimentary rocks) continues in the westward aljillovic & srclllac: thc middle and upper permi dll dcpo~its ill gorski kol al .. direction from the east, into the groden formation (or its equivalenlthe verucano-lombardo formation), and afterward into lagoon, evaporite or shallow marine facies of the bellerophonc formation (broglio lor­ ig a & cass inis, 1992). only in the region cast of the adige valley can this contact be considered as a continuous conformable sequence (broglio lori­ ga & cassinis, op. cit.) . 4. conclusion from the numerous papers that dealt with the palaeozoic complex of the gorski kotar, no explicit cri­ teria are availab le for the exact definition of the youngest permian facies, due to the absence of auto­ chthonous fossils. also none of the facies referred to can be recognized with certainty as of upper permian age. the complex tectonics in the gorski kolar region do not allow conclusions to be drawn about the unique middl e upper permian sedimentological succession. the facies diversity and their frequent vertical and lat ­ era l variation docs not permit conclusions about their unique superposition, and therefore it cannot be stated that the youngest facies corresponds to conglomerates and sandstones. the superposition criterion used for the determination of the youngest facies is therefore not applicable. the interpretat ion of a continuou s transition from the permian , dev eloped as groden clastic rock faci es, into shallow marine sedimentary rocks of the lower triassic, does not exist either in the adjacent areas (ve lebit, s lovenia) or the wider region of the southern alps. the continuos transition can only be found in carbon ate succcssions (upper pe rm ian dolo­ mites fro m vclebit, and the bellerophone formation in the alps) . the frequent occurrence of coarse grained sedimen­ tary rocks and sandstone permit s the assumption that molasse typc scd imentation occurred as a consequence or intensive eros ion of uplifted areas as inferred by herak & tomic (1995). although no direct evi­ dence exists for the age of the permian facies , an indi­ rect concl usion about the age can be made from the fos­ si l analysis of limestone pebbles and calclithites, which indicate that the age of the gorski kotar permian com­ plex corresponds to the clastic trogkofel beds, i.e. mid­ dle permian (s remac & alj inoyi c, 1997 thi s. vol). the molasse type depos ition is the consequence of illt ens ive tectonics in the lowe r permian or at the beginning of middle permian, as indicated by grubic ( 1980). the absence of upper permian carbonate deposition in gorski kotar, that would be simi lar to that which exis ted in the adjacent velcbit region (tisljar et ai. , 1991) or further to the cast and southeast in middle bosnia and dal matia (tlsljar, 1992) , also supports the presumption that a break in sedimentation exis ts at the permo-triassic boundary. the lack of carbonate and evapori te sedimentation, which is in contradiction 239 with the upper permian charac terist ics of the wider region indicates that the gorski kotar region was under the influence of an emergence phase at that time. depo­ si tion recommences in the lower triassic after a hiatu s in the upper permian with a transgression of a shallow sea onto a !lattened relief, which is the reason why an angular discordance, and other elements characleristic of a gradual transition across the boundary between the upper permian and the lower triassic arc missing. thc gradual transition, as was until now presumed fo r the permo-triassic boundary in gorski kotar, sho­ uld be manifested either with a gradual increase or dec­ rease of certain parameters across a very short segment of the colum n. th is means that only the outcrops per­ mitting continuous sampling can document these chan­ ges. for the permo-triassic boundary, generally accept­ ed criteria exist (see sweet et ai. , 1992) that must be displayed within a small segment of a vertical sequ­ ence, thus further work on this task seems to be inevi­ table. from the known, published data it is not possible to infer the conclusion about continuous sed imentation on permo-triassic boundary. acknowledgements this work benefited from the thorough review and helpful comments by dr. a. ramoys, dr. y. jelas­ ka and dr. j. robson to whom we would like to express our gratitude. 4. references aljinovic, d. (1997): facijesi klasticnih sedimenata mladega paleozoika i starijega trijasa gorskoga kotara (late paleozojc and early scythian clast ic facie s).unpublished phd thes is , university of zagreb, 163 p. assereto, r. , bosellini, a., fantini-sestini, n. & sweet, w.e. (1973): the permian-triass ic boundary in the southern alps (italy).in: logan, a. & hills, l.v. (cds.): the permian and triass ic system s and their mutual boundary. can. soc. pet ­ rol. geol. mcm., 2, 176199. brendner, r., donofrio, d.a. , krainer, k. , mostler, h., nazar ow, w., rescii, w., stingl, v. & weisser, h. (1986): events at the permi an-triassic boundary in the south ern and northern alps .in: field conference on permian and permian-triassic boundary in the south-a lpinc segment of the western tethys and additional reports. abstracts , 15-16, brescia. broglio loriga , e. & cassinis, g. ( 1992): the permo-triassic boundary in the southern alps (ita­ ly) and in adjacent periadriatic rcgion s.in: swe­ et, w.e. , yang , z. , dickins, i .m. & yin, h. (cds.): permo-triassic events in the eastern tethys; 240 strat igraphy , cl assification and relations with the weste rn tet hys, international geological corre la­ tion program me project 203, permo-triassic events or eastern t ethys region and their intercontinental correlat ion, cambridge university press, cambri ­ dge, new york, port chester. melbourne, sidney, 78-97. bugg isch, w. (1 978): die grodencr sehiehten (pe­ rm , suclalpcn). sedimentologi sche und gcochcmi s­ che unt ersuchungen zur unterscheidu ng mariner unci konlincnlalcr sedimentc.geoi. rundschau, 67, 149180. gugg isc i-i , w , flogel, e., leitz, f . & ti etz, g. f. ( 1976): die fazie lle und pal aogeographi se he entwicklu ng im penn del' karnischen alpcn und in den randgebieten.geol. rundsehau, 65 , 649-690. cass inis, g., massari, e , neri, e. & ventu ri­ ni, e. ( 1988): the continental permian in the sou­ the rn alps (italy) a rev iew.geol. w iss., 16, 11 26. cer ina, d. ( 1986): kosa lam inaeija indikacija bari ta.5. skup sedimentologa jugoslavije, abstracts, 11 8121, grioni. farabego ll , e., flo gel, h.w. , levanti, d., noe, s., pas ini, m. , perri, m.e. & venturi­ ni, c. (1986): the tarvisio breccia and val garde­ na sandstone: lit hostratigraphy and paleoenviron­ mellis. the perm ian{triassie boundary carnic and comelico.in : fi e ld conrerence on perm ian and penll ian-triassic boundary in the south-a lpine seg­ mcnt or western te thys. excurs ion guidebook, socie ta geologica ital iana, 55-72, pavia. flogel, h.w. & faupl, p. (eds .) (1987): geody­ nami cs of the eas te rn alps .deuticke, vicnna, 418 p. roetter le, f. ( 1855) : geologische unt ersuehung des kroat ischen kustcnlandcs.jahrb. del' k. k. geol. r. a., bcl. vi, 4 17 p., wicn. germovse k, e. (! 962): 0 mlaj sih pa leozojski h in soscclnjih mczozojskih skladih juzno od koccvja. ­ geologija, 7, 85101 , ljubljana. grub h:, a. (1980): earl y mi ddle permian break in thc geotec toni c evolulion of yugoslav dinarides.­ in : mctalogcnes is o f uranium. 26t h rnler. geol. cong., pari s, scct. 13.2.2., geoinstitut, beograd , 203-214,1981. 1-1 a uer, f. ( 1868): geo logisehe ubersieh teskarte den ostel'reichi schen monarchic.blah vi, ostl. alpen­ liinder, 1:576000, wien. hera k, m. & to mic, v. (1995): continenta l subdu­ cti on tectonics in the high carst dinarides of west­ ern croatia. geologia croatica, 48/2, 161 -166. ita li an research group (1986): field confergeologia croalica 50/2 ence on permian and permi an-triassic bou ndary in the south-al pine segment of the weslcri1 te thys .­ excursion fiel d guidebook, sociela geologica ita l­ iana, igcp project no. 203, collllllc rc iale pavese, 158 p. , pavia. jelaska , v. & prohic, e. (1982): facije lne karak­ teristike perm skog f1 isa poclru cja mrzlc vodicc (gorski kotar, hrvatka) (facial characteristics o f the mrzl a vodica fly sch (gorski kotar, croati a)).10. jubil arni kongres geologa jugoslavije, zbornik rado­ va, 1,473-482, budva. jurkov ic, i. (1959): pojave barita u hrvatskoj (bari ­ te occurrences in croatia). geol. vjesni k, 12, 115 124. kochansky-devide, v. (1965): karbonske i per­ mske fuzulinidne fora min ifere velebi ta i like. srednji i gornji pe rm (die fusul inidcn fol'am in ifer­ en aus dem carbon und perm im vejcbi t und in del' lika (kroalien) . mill icres und oberes pcfln).acta geol. , 5, 10 1-1 37, zagreb. koc i-i ansky-devide, v. ( 1973): tro"gkofciskc na­ s lage u hrvatskoj (die trogkofejabl agcrun gcn in kroatien).gcol. vjesnik, 26, 41 -5 1. kochansky-devide, v. (1978): tanchintongia­ c ine abcrrante permische bivalve in europa.­ paliionl. z ., 52/3-4, 213-218. kochans ky-devide, v. ( 1982): upper paleozo ic of the velebi t mi.in: srem ac, 1. (cd.): ig cp­ projec l no.5, yugoslav working gro up , fie ld meeting 1982, velebit mi., fie ld g uide, 815 , zagreb. koci-iansky -devide, v., sremac, 1. , jelas ­ ka, v. & palcic, l. (1982): geoloska ekskurzija ­ gornji paleozoik velebita. in : sremac, j. (cd.): igcpproj cct no.5, yugoslav working grou p, field meeting 1982, velebit mi., field guide, 16-41, zagreb. krainer , k. (1993): la te-and post-va ri scan sedi ­ mcnt s of the eastern and southern alps .in : raumer von, j .e & neubauer, c. (cds.) : pre­ mesozoic geo logy in the alps. springerverlag, berlin , i-ie idelberg, 537-549. massari, f. , conti, m.a. , fontana, d. , i-iel­ mold, k., mariotti, n. , neri, e. , nicosia, u., ori , g.g. , pasini, m. & pittau, p. (1988): the val gardena sandstone and be llcrophon forma­ ti on in the bletterbach gorge (a llo ad ige. ital y) : b iostrat igraphy and sccl imentoj ogy.mem . sci. geol., 40, 229-273. m ilanovic, m., & kochansky -devide, v. ( 1968): razvoj palcozoika u vanjskim dinarid ima hrvatske (the deve lopment of the paleozoic in lhe outer dinaric alps of croatia). 1 ko l. geol. dinari ­ dov , i , 15-20, ljubljana. aljino\'ic & srctll:lc: tile middle and upper pemli:m deposils in gorski kol:h ... ori, g.g. & yenturini, e. (1981): facics continen­ tali penniane ne lle a lpi carniche .rend soc. geot. ital., 3, 2 1-24. palinkas, l.a. & sinkovec, b. (1986): tidal tiat fac ies and bari te mine ra lizat ion in gorski kotar. ­ geol. vjesnik, 39, 215-224. pali nkas, l.a. & sremac, j. ( 1989): barite-bear­ ing stromato lites at the permian-triass ic boundary in gorski kotar (croatia).mem. soc. geo l. it. , 40 ( 1987), 259-264. pali nka s, l.a., pezdtc, j. & sinkoyec, b. ( 1993 ): the lokvc baritc deposit , croat ia: an example of early diagenetic sedimentary ore de p­ osits.gcol. croatica, 46/ 1, 97-106. raffaelli , p. & scaynicar, b. ( 1968) : naslage gornjeg pa leozo ika like i gorskog kotara (les couches du pal60zoique superieur dans la region de la lib ct dc gorski kotar).i kol. geol. dinaridov, i, 21 -27, ljubljana. ramoys, a. ( 1968): razvoj palcozoika v slovcnskem delu zunanj ih dinaridov (die entw ieklung des pala­ ozoikums im siowen ischcn te il der aussendinari­ den) .i kol. gcol. dinaridov, 1, 7-19, ljubljana. ramoys , a. & koc hansky-deyid e, y. (1965): ra zvoj mlaj sega palcozoika v okolici ortneka na dolenjskcm.razpravc iy razreda sazu, 8, 31941 6, ljubljana. ramoys, a. & kochanskydeyid e, y. (198 1): permian-triass ic boundary at bru sane village in yelebit mt. gco logija, 24/2, 327-330, ljubljana. raumer yon , j. f. & neubauer , f. (cds.) (1993): pre-mesozoic geo logy in the a lps.spri nger-ver­ lag, berlin, heidelbcrg, 677 p. salopek, m. ( 1942): 0 gornjem palcozoiku vclcbita u okolini brusana i baskih ostarija. rad hrv. akad zllan umjct. , 274, 2 18-282, zagreb. salopek, m. ( 1948) : 0 gornjem palcozoiku sjevero­ istocnog podnozja vclebita i like.prir. istraz. jugosl. akad. znan. umjel. , 24, 101 169, zagreb. salop ek, m. (1949a): gornji paleozoik u okol ini mrzle vodice u gorskom kotaru.ljetopi s jazu, 55(1946-1948), 175184, zagreb. salopek , m. ( i 949b): 0 gornjem palcozo iku u okoli ­ ni gcrova i trsca u gorskom kotaru.ljetopi s jazu, 55( 19461948), 193-198, zagreb. sa lopek, m. ( 1960): 0 gomjem paleozoiku u okolini mrzle vodiee i crnoga luga.acta geo \. , 2 (prir. ist!'. 29), 12 1-132, zagreb. salopek, m. ( 1961): geolosk i odnosi paleozojskog prodora okoline smrecja, trsca i cabra u gorskom kotaru .acta geol. , 3 (prir. istr. 3 1), 243-249, zagreb. 241 sa yic, d. & dozet, s. ( 1984): osnovna geoloska karta m i: 100 000 , list delnice (basic geolog ical map, sheet delnice). savczni geoloski zavocl , beo­ grad. sayle, d. & dozet, s. ( 1985): tumac osnovne geo­ loske karte m i : 100000, list dclnice (explanatory notes for sheet de lni ee) .savezni geoloski zavod , beograd, 66 p. schon laub, h.p. (1993): strat igraphy, biogeogra­ phy and climatic relati onships of the alpine palaeo­ zoic .in: raumer yon j.f. & neubauer , f. (eds.) (1993): pre-m esozoic geology in the alps. springer-verlag, berlin , he idelberg, 65-91. sremac, j. ( 199 1): zone ncoschwagerina craticulif­ era in the middle vele bit mt. (croat ia , yu gosla­ via).geologija, 34, 7-55 , ljubljana. sremac, j. & alj inoy ic, d. (1997): upper palaeo­ zo ic fos s il s from c lastic sedimentary rocks in the gorski kotar region. geol. croat. , 50/2, 187199. sweet, w.e. , ya g, z., d1ckins, j.m. & yin, i-i. (cds.) (1992): permo-triassic events in the eastern tethys; stratigraphy. c lass ifi cat io n and re lations with the western tethys.igcp project 203 : per­ mo-triass ic events or eastern te thys region and the ir intercontine nt al co rre lation. cambrid ge uni ­ vers ity press, cambridge, new york, port chester, mclbourne, sid ney, 78-97. sca ynicar, b. & susnjara, a. ( 1967): geoloska i petrografska is traz ivanja trijaskih nas laga u gorskomc kotaru (pod rucje lokve i gerovo) (recherches geo log iqucs c t pelrographiqu cs des couches trias iques de gorski kotar en croati e (region lokve-gerovo)).geo l. vjesn ik, 20, 87106. susnjara, a. & sinkoyec, b. (1973): st ratigraf­ ski polozaj iczista barita gorskog kotara (the strat i­ graphic pos ition of the gorski kotar b:tri te depo­ sits) .geol. vjcsnik, 25, 149154. tis lj ar , j. (1 992): origin and deposit ional environ­ ments of the e vaporit e and carbonate comp lex (upper permian) from the central part of the dinar­ ides (southern croatia and weste rn bosni a).geo\. croat., 45, !o5-127. tislja r, j. , vlahoyic, i. , sremac, j., yelle, i. , yesel! , y. & stankoyic, d. (1991): excursion a yelebit mt., permian-jurass ic.in: yell c, i. & ylahovic, i (cds.): some aspects of the shallow water sedimentation on the adriatic carbonate pl at­ fo rm (pe llllian to eocene). the second inte rnational symposium of th e adriatic carbonate plat form, zadar, may 1991, excursi on gu ide-book, i-50, zagreb. yell c, i. , maticec, d. , ylahoyic, i. & t is­ ljar , j. (1995): strati graphic succession of juras­ s ic and lower cretaceous ca rbonates (bat i.lon ian 242 uppcr albian) in western istria. in: vlahovie, i. & velie, i. (eds .): first croatian geological congrcs, excursion guide-book, 31-66, zagreb. geologia croalica son vogl, v. (1913): di c palaeodyas von mrzla vodica im kroat ien.mitt. jahresb. der geo!. r.a , bd. xxi, h. 5, budapest. manuscript received apri l 14, 1997. revised manuscript accepted november 10,1997. 269 korbar & husinec.indd 1. introduction the croatian island of cres is situated in the northern part of the adriatic sea (fig. 1). it is built up of predominantly cretaceous carbonates, although there are some minor scattered outcrops of palaeogene deposits (polšak, 1967a; magaš, 1968; mamužić, 1968; šikić et al., 1969). a succession of lower cretaceous carbonates, approximately 800 m thick, ranges in age from the early neocomian to the latest albian, and is characterized by shallowmarine deposits sporadically interrupted by minor emersion horizons (fuček et al., 1995). major facies differentiation took place during the cenomanian (husinec et al., 2000; korbar et al., 2001), as shown by lateral changes from peritidal restricted facies with radiolitid bouquets, via marginal coarse-grained bioclastic facies predominantly with recumbent rudists (ichthyosarcolitids and caprinids) to deeper-water calcisphaerulid facies. biostratigraphy of turonian to (?)coniacian platform carbonates: a case study from the island of cres (northern adriatic, croatia) tvrtko korbar and antun husinec from the fossil association studied by them, previous authors (polšak, 1967a; magaš, 1968; mamužić, 1968; šikić et al., 1969; mamužić et al., 1982) considered the youngest cretaceous deposits on the island of cres to be of cenomanian–lower turonian age. however, that association is now considered to be restricted to the cenomanian (gušić & jelaska, 1990). later, jelaska et al. (1994) proposed that sedimentation was interrupted close to the cenomanian–turonian boundary and that the gap lasted until the eocene (lutetian) transgression. in contrast to the ne part of the island, where the youngest strata below the regional k–t emersion horizon are of cenomanian age, deposition continued in the sw part into the post-cenomanian (korbar, 1999; korbar et al., 2001; korbar & husinec, 2002). the aim of this paper is to describe the fossil assemblage in the youngest cretaceous carbonate deposits on the island of cres, as well as to interpret the age and depositional palaeoenvironment of the investigated strata. the boundary between these and the underlying cenomanian–turonian deeper-water limestones is marked by a fault. nevertheless, field investigations indicated that no significant relative vertical displacement has occurred between these two limestone packages. an approximately 70 m thick succession situated west of the village of martinšćica was sampled and analysed (fig. 2), and its palaeoenvironments and fossil assemblages are described here. the succession defines a lithostratigraphic unit of post-cenomanian deposits occupying exclusively the southwestern part of the island (see location map, fig. 1). several samples containing embedded hippuritids were also collected from deposits belonging to the unit (sampling points ci, cl and cn; fig. 1). on the basis of detailed geological mapping of the area and micropalaeontological analyses of the samples, the deposits represent laterally equivalent strata of the same age and depositional environment as those analysed at the martinšćica section. the morphotype nomenclature and terminology for rudist bivalves, e.g. “elevator”, “recumbent”, “bouquet”, “cluster”, is used according to the scheme of skelton & gili (1991), summarised by ross & key words: adriatic carbonate platform, turonian, coniacian, rudists, benthic foraminifera, island of cres, croatia. institute of geology, sachsova 2, p.o.box 268, hr-10000 zagreb, croatia; e-mail: korbar@igi.hr abstract the shallow marine carbonate deposits on the island of cres, overlying deeper-water cenomanian–turonian limestones, are characterized by an assemblage of rudists, benthic foraminifera, and associated microfossils. the paucispecific character of the fossil association suggests deposition in shallow areas of a carbonate platform, with low current-energies and restricted circulation. similar assemblages indicating similar palaeoenvironments, are common in the upper cretaceous deposits of the adriatic carbonate platform and adjacent areas. the assemblage of rudists (hippuritids) and microfossils indicate the turonian to (?)coniacian age of the investigated carbonate succession. the biostratigraphic importance of the so-called “primitive” hippuritids within the micropalaeontologically poorly defined biostratigraphy of deposits of this age, is accentuated. geologia croatica 56/2 173–185 2 figs. 2 pls. zagreb 2003 174 geologia croatica 56/2 175korbar & husinec: biostratigraphy of turonian to (?)coniacian platform carbonates... skelton (1993). since radiolitids are poorly preserved and of minor biostratigraphic value, only several hippuritid specimens were analysed. 2. palaeoenvironments the strata investigated are characterized by predominantly mud-rich limestones with numerous specimens of aeolisaccus and thaumatoporella (pl. ii, figs. 5, 6). the paucispecific character of the fossil association suggests deposition in shallow areas of the carbonate platform, with low current-energies and restricted circulation. contrary to the older midcretaceous shallow-water limestones that yield several important cosmopolitan foraminiferal index taxa of the family orbitolinidae (husinec et al., 2000; husinec, 2001), the post-cenomanian strata contain a low-diversity association. however, the association implies that following the deposition of the deeperwater limestones that characterize the underlying succession, the environment again became favourable for population by larger foraminifera and, sporadically, rudists. rudist bivalves are the most frequent macrofossils within the strata investigated. radiolitids (radiolitidae) have been found both in autochthonous (in situ bouquets, clusters and small lenticular thickets) or paraautochthonous position (displaced locally in the vicinity of their habitats). rare hippuritids (hippuritidae) have been found in bouquets characterized by three to four conjoined specimens. in the vicinity of the village of martinšćica (martinšćica section, fig. 2), thickbedded peritidal limestones (pl. i, fig. 1) contain some radiolitid clusters and thickets (biostromes) sporadically including hippuritids. radiolitids commonly occur in the uppermost part of some beds (pl. i, fig. 4). minor subaerial exposure surfaces are also common at the tops of some beds. solitary hippuritids (elevators) or small hippuritid bouquets (sample cn–864d contains an embedded bouquet of 4 hippuritid specimens – pl. i, fig. 7) were found within subtidal mud-rich limestones. depositional environments were similar to those characterized by the turonian to upper santonian limestones of neighbouring southern istria (moro, 1997; vlahović et al., 2002). thus, the carbonate platform regime was re-established in the area during the middle turonian, following the cenomanian/turofig. 1 a) location map of the island of cres; b) location map of the area of post-cenomanian deposits outcrops (hatched), the sampling points and the martinšćica section (arrows). 174 g eologia c roatica 56/2 175 k orbar & h usinec: b iostratigraphy of turonian to (?)c oniacian p latform c arbonates... fig. 2 s tratigraphic distribution of m icrofossils and rudists w ithin the m artinšćica section (m odified after k o r b a r , 1999). j nrnmrn ]< "ii '" a ~ ~ ~ ~ ~ i i i i i i ~ ~.a 3 c"l '" r ""c en ;;c en ::i: l:: m~mq) m ocdccd 0> -"cn(l)3 cd:::loc"rl :::::j-a--·o cd-<!d)"j"" -<" cd ::::j en cd c" oi"c "" @ en :::l.cd .'" a., 8.m 01 !!!k!!!.§: ... !:!!.::::jcn~ -::rurcdcd ill cd co _. en cn cd~ a. 0> 5,.ci.i :f c c: c.o"'c " cd 3 <> iil' ct::e en cd 0 '0) j~mcdc:~ .9 03= q) :::l.=r=mc: c.:f a cuc'end) --_. "c -cd cq.n ::r cd c':;:::t.,= "" "':$. >< c.., 3 o:1} cd "8~!ilcd i cn en rn ~tt q) c: 'c en acd_.:::l oicd::j 050 a. :::3. cd _~ en=::::!: rn 0a c:g.::e r01 3 iil'= "" m cd !il 3· ::r col ~ cncd m , z ~ iii o~g c peritidal, mainly mud-rich and skeletal limestones with common o i~ subaerial exposure surfaces and small radiolitid biostromes. upper part t~i lithology is highly recrystallised and redish coloured with paleokarst 4" features at the top. • it .' .j' spiro/oculina sp. biplanata peneropliformis pseudonummo/oculina heimi -------------------aeolisaccus kotori -----------------thaumatoporel/a panovesiculifera 3: nezzazata simplex c; ?nummo/oculina sp. i!! oj ),. :;! ;;c i cd ~ '" c: _. ::j c. "c ~ iii' § _. "c ::r f!l. c: ('j. :::i • ., '" ct ~ 0' " 0· 0: iil ~ 1 !2 ., cd 3 .. ~ en 5· fir en is' ° if ~ iil -< 0 , en 3 !ll, pseudocyclammina sphaeroidea "t1 0 peneroplis panus en scandonea samnitica en i'" vemeuilina sp. en tritaxia sp. -valvulammina sp. moncharmontia apenninica -radiolitidae ;;c hippurites ct. resectus c: c note: most of the detennined rudists were found in laterally iii -i equivalent strata (see location map on fig. 1). en ct 0 c: .c c: 1} turonian (?)coniacian ""ii approx. chronostratigraphy cd ~ 176 geologia croatica 56/2 177korbar & husinec: biostratigraphy of turonian to (?)coniacian platform carbonates... nian drowning of the platform (gušić & jelaska, 1990, 1993; jenkyns, 1991; davey & jenkyns, 1999; vlahović et al., 2002). similar associations, and consequently depositional environments, are common in the upper cretaceous of the adriatic carbonate platform and adjacent areas. the investigated sequence of strata on the island of cres can be correlated with the lower part of the gornji humac formation, (above the gračišće member) of (?)late turonian–early campanian age, and was originally described from the island of brač, (glovacki jernej & jelaska, 1986; gušić et al., 1988; gušić & jelaska, 1990). similar deposits of (?)late turonian–early santonian age, are known from the island of dugi otok (fuček et al., 1990), and from the islands of ist and olib (moro & jelaska, 1994). on the trieste–komen plateau it corresponds to the lower part of the sežana formation, which is of late turonian–early campanian age (jurkovšek et al., 1996). furthermore, in terms of facies and biostratigraphy, the studied sequence can be correlated with the lower part of the borgo grotta gigante member from the trieste karst (cucchi et al., 1989), and the lower part of the calcari di aurisina (“calcari a rudiste”) from the isontino karst (tentor et al., 1994). in the central apennines, the upper turonian–lower campanian carbonate deposits are also characterized by predominantly mud-rich lithologies, sporadically containing numerous fragments of radiolitids and hippuritids, and with microfossil associations that become richer and more diversified upwards in the section (chiocchini et al., 1994). in general, this distribution represented by radiolitids dominating hippuritids in more internal peritidal cycles, seems to be typical of the central/southern tethyan carbonate platforms (carannante et al., 2000; stössel & bernoulli, 2000; moro et al., 2002; korbar, 2003). 3. systematic palaeontology 3.1. rudists analysed rudists are referred to the family hippuritidae according to the diagnoses of dechaseaux & coogan (1969), skelton (1978) and skelton & smith (2000). rudist determinations were made according to descriptions of european rudist fauna (douvillé, 1890–94; toucas, 1903–04) and descriptions of rudist fauna collected in the neighbouring areas (polšak, 1967b). order hippuritoida newel, 1965 superfamily hippuritoidea gray, 1848 family hippuritidae gray, 1848 genus hippurites lamarck, 1801 hippurites sp., cf. h. resectus defrance, 1821 (pl. i, figs. 2, 3, 5–8) 1903 hippurites (orbignya) requieni matheron; toucas, text-fig. 23–29. 1903 hippurites (orbignya) requieni var. resecta defrance; toucas, text-fig. 30, 31. 1903 hippurites (orbignya) requieni var. subpolygonia toucas, text-fig. 32. 1967 hippurites (hippuritella) incisus douvillé; polšak, p. 109, text-fig. 33. 1997 hippurites requieni; moro, pl. 9, fig. 3. 1999 hippurites requieni matheron; caffau, pl. 2, fig. 1. 2002 hippurites cf. requieni/incisus; vlahović et al., p. 126, text-fig. 5. material: ten limestone samples containing embedded rudists were collected within the martinšćica section (figs. 1, 2) – cmb (1 specimen), and within laterally equivalent strata occupying the investigated area (location map of the sampling points ci, cl and cn on fig. 1): ci–861 (1 specimen), cl–1195 (2 specimens), cn–864 (1 specimen), cn–864a (3 specimens), cn–864c (1 specimen with broken ligamental pillar), cn–864d (1 specimen as a part of a bouquet of four hippuritid specimens), cn–952 (1 specimen), cn–953 (1 specimen) and one unlabelled sample (1 specimen). all of these 13 specimens are transverse sections of right valves embedded in slightly recrystallized limestones. the samples are stored at the repository of the institute of geology in zagreb (croatia). description: the valves are 12–30 mm in diameter. anterior (ligamental) pillars are triangular with wide bases and truncated apical parts. central pillars are slightly wider and shorter than the more protruding posterior one. central and posterior pillars are characterized by rounded heads. some specimens are characterized by central and posterior pillars that are as long as the anterior ones, while the posterior pillars have a slightly narrower bases than the central ones. the angles between anterior and posterior pillars ranged between 80 and 110 degrees. stratigraphic distribution: turonian (toucas, 1903–04; mamužić et al., 1976; sánchez, 1981; philip, 1998; vlahović et al., 2002), upper turonian (polšak, 1967b; slišković, 1968; polšak & mamužić, 1969; polšak et al., 1982; caffau, 1999), upper turonian–?coniacian (steuber, 1999a) or middle–upper turo176 geologia croatica 56/2 177korbar & husinec: biostratigraphy of turonian to (?)coniacian platform carbonates... nian (philip in hardenbol et al., 1998; platel, 1998; simonpiétri, 1999). remarks: there are a few transverse sections of right valves of hippurites requieni matheron shown in toucas (1903–04) that are characterized by a wide range of the angles between the anterior (ligamental) pillar and the second pillar. it is not clear what the reason is for such a strict value as 120° for a determination of the species as established by toucas (1903–04) in the text. moreover, these angles vary in relation to the departure of the right valve transverse section from circularity, which in turn depends on the available space during growth (steuber, 1999a). that is why we are of the opinion that all specimens described in this paper are consistent with the description of the morphologically variable species hippurites resectus defrance revised by simonpiétri (1999). according to the same author hippurites requieni matheron represents a synonym of h. resectus defrance. complete synonymy lists of all synonyms, including references, are given in sánchez (1981) and steuber (1999c). the small number and poor preservation of collected specimens did not allow morphometric analysis. therefore, specimens are referred to the species by comparison of the internal morphological characters of their right valves (i.e., resemblance of morphology of the pillars and their distribution along the shell interior). we are aware that determination based only on pillar morphology can be difficult and is not always reliable (steuber, 1999a). consequently, our determinations are tentative, but can be used for the purpose of this paper (i.e., to prove post-cenomanian carbonate deposition on the island of cres). 3.2. microfossils ten samples were obtained from the martinšćica section (see fig. 2) and were examined in thin sections. the following microfossil taxa have been determined: aeolisaccus kotori radoičić, biplanata peneropliformis hamaoui & saint-marc, moncharmontia apenninica (de castro), nezzazata simplex omara, ?nummoloculina sp., peneroplis parvus de castro, pseudocyclammina sphaeroidea gendrot, pseudonummoloculina heimi (bonet), scandonea samnitica de castro, spiroloculina sp., thaumatoporella parvovesiculifera (raineri), tritaxia sp., valvulammina sp. and verneuilina sp. other foraminifera found in the area investigated belong to the families miliolidae, nezzazatidae, charentiidae, coskinolinidae, spiroloculinidae, hauerinidae, verneulinidae, tritaxidae, and valvulinidae (according to loeblich & tappan, 1988). they are not important in terms of biostratigraphy because of their relatively long stratigraphic ranges. the morphologic characteristics of the biostratigraphically and palaeoecologically most important species are briefly discussed, while their stratigraphic ranges are discussed in the following chapter. order foraminiferida eichwald, 1830 suborder textulariina delage & hérouard, 1896 superfamily biokovinacea gušić, 1977 family charentiide loeblich & tappan, 1985 genus moncharmontia de castro, 1966 moncharmontia apenninica de castro, 1966 (pl. ii, fig. 1) 1966 neoendothyra apenninica de castro; de castro, p. 14–19, text-figs. 5, 6, pls. i–v 1988 moncharmontia apenninica de castro; gušić et al., pl. ii, figs: 8, 10, 11 1990 moncharmontia apenninica de castro; fuček et al., pl. ii: fig. 8 1994 moncharmontia apenninica de castro; moro & jelaska, pl. ii: fig. 5 material: a few specimens were observed in thin sections (samples cma–6, cma–7, cma–8, and cma–10; fig. 2). the samples and thin sections are stored at the repository of the institute of geology in zagreb (croatia). description: test planispirally enrolled, involute, without uncoiled stage. wall finely agglutinated, outer wall seemingly perforated, inner visibly smooth. aperture cribrated with pores. remarks: despite the lack of appropriate sections and small number of specimens studied, they are attributed to moncharmontia apenninica due to their characteristic overall morphology. stratigraphic distribution: turonian–campanian (de castro, 1966). superfamily loftusiacea brady, 1884 family cyclamminidae marie, 1941 subfamily choffatellinae maync, 1958 genus pseudocyclammina yabe & hanzawa, 1926 pseudocyclammina sphaeroidea gendrot, 1968 (pl. ii, fig. 2) 1968 pseudocyclammina sphaeroidea gendrot, p. 674–675, pl. iv: figs. 1–5 1990 pseudocyclammina sphaeroidea gendrot; fuček et al., pl. ii: fig. 7 1991 pseudocyclammina sphaeroidea gendrot; fuček et al., pl. ii: fig. 6 178 geologia croatica 56/2 179korbar & husinec: biostratigraphy of turonian to (?)coniacian platform carbonates... material: several specimens were observed in thin sections (samples cma–5, cma–6, cma–7, and cma–8; fig. 2). the samples and thin sections are stored at the repository of the institute of geology in zagreb (croatia). description: test involutely enrolled, outer form inflated, almost sphaerical. final coil with clear sutures slightly depressed. endoskeleton with labyrinthic septa. wall agglutinated. cribrate aperture. remarks: the specimens were observed in equatorial and oblique sections. stratigraphic distribution: turonian–senonian (see text – section 4). suborder miliolina delage & hérouard, 1896 superfamily soritacea ehrenberg, 1839 family soritidae ehrenberg, 1839 subfamily praerhapydionininae hamaui & fourcade, 1973 genus scandonea de castro, 1971 scandonea samnitica de castro, 1971 (pl. ii, figs. 3, 4) 1971 scandonea samnitica de castro, p. 5–6, 16– 65, text-figs. 1–10, 12–15, pls. i–xii, xv–xvii, 1988 scandonea samnitica de castro; gušić et al., pl. i: fig. 5 1990 scandonea samnitica de castro; fuček et al., pl. ii: figs. 3–6 material: several specimens were observed in thin sections (samples cma–3, cma–5, cma–6, cma–7, cma–8, and cma–10; fig. 2). the samples and thin sections are stored at the repository of the institute of geology in zagreb (croatia). description: test enrolled, initially in various planes, later planispiral and involute. final stage may be uncoiled and rectilinear. endoskeleton with basal layer and rudimentary(?) subepidermal partitions in the adult chambers and in the chambers of adult stage. wall calcareous, imperforate, porcellaneous, outer wall very thick. cribrate aperture. remarks: the specimens were observed in median and axial sections. stratigraphic distribution: turonian–senonian (see text – section 4). 4. discussion the hippuritid taxon hippurites resectus defrance (including synonyms, see section 3.1.), that characterizes the investigated area, is well known from numerous localities on the adriatic carbonate platform and adjacent areas. this taxon has been commonly attributed to the upper turonian (polšak, 1965; slišković, 1968; polšak & mamužić, 1969; mamužić et al., 1976; polšak et al., 1982; gušić & jelaska, 1990; fuček et al., 1990; cestari & sartorio, 1995; caffau, 1999) or an even wider range, e.g. upper turonian–?coniacian (steuber, 1999a) and upper turonian–lower santonian (moro, 1997; moro & jelaska, 1994). on the other hand, simonpiétri (1999) revised the taxonomy and stratigraphy of a few “primitive” hippuritid species from western europe, including type specimens, and concluded that h. resectus is middle– late turonian in age. furthermore, recent results based on strontium isotope stratigraphy and morphometric analyses of the hippuritidae from central and eastern europe, imply that vaccinites cornuvaccinum and v. inaequicostatus (see cestari et al., 1996; steuber, 1999a), traditionally considered as santonian–early campanian in age (sánchez, 1981; polšak et al., 1982; steuber, 1999a), are no younger than coniacian (steuber, 1999b; steuber & höfling, 1999; steuber, 2001). however, the revised chronostratigraphy of these taxa should be confirmed for the adriatic carbonate platform domain analyzing the specimens from southern istria (localities in polšak, 1967b). nevertheless, there is a need for biochronostratigraphic recalibration according to the new cretaceous biochronostratigraphy (hardenbol et al., 1998). finally, the association of hippuritids described in this paper suggests the middle–late turonian age of the strata investigated. the microfossil association does not contain many stratigraphically relevant taxa. moreover, the stratigraphic ranges of the only three “index” species are still disputed. the least debate surrounds the first appearance of moncharmontia apenninica de castro, which is the upper turonian (e.g. de castro, 1966; gušić & jelaska, 1990; chiocchini et al., 1994). however, various authors have given very different data on the stratigraphic range of scandonea samnitica de castro: lower senonian (chiocchini et al., 1994), lower santonian–lower campanian (hardenbol et al., 1998), upper santonian (bilotte, 1984, 1986), and turonian–santonian (de castro, 1971) – maybe even to maastrichtian (fleury, 1980; gušić & jelaska, 1990). this is also the case with pseudocyclammina sphaeroidea gendrot: turonian–santonian (fleury, 1980), coniacian–santonian (bilotte, 1984; hardenbol et al., 1998), and santonian (gendrot, 1968). in central croatia, the association of these three “index” species occurs in the lower senonian rudist limestones (velić, 1973; velić et al., 1980). fuček et al. (1991) reported on resedimented shallow-marine bio178 geologia croatica 56/2 179korbar & husinec: biostratigraphy of turonian to (?)coniacian platform carbonates... clastic material containing the aforementioned foraminifera, interbedded with deeper-water carbonates from dugi otok island. undisturbed autochthonous layers of pelagic limestone contain planktonic foraminifera that clearly indicate the middle to late turonian age of these deposits. however, there is one additional clue to narrow the stratigraphic range of the examined sequence, namely, that foraminifera which appear in the santonian on the adriatic carbonate platform (dicyclina schlumbergeri munier-chalmas, accordiella conica farinacci, keramospherina tergestina (stache), scandonea mediterranea de castro, and nummofallotia apula (luperto sinni) – e.g. gušić et al., 1988; gušić & jelaska, 1990), were not found in the study area. therefore, based on the microfossil association, and knowing that underlying deeper-water deposits are dated to the latest cenomanian–earliest turonian, the age of the investigated sequence on the island of cres is likely to be (middle) turonian to (?)coniacian. additional investigations and correlations with regional and global stratigraphic charts and sequence stratigraphy, as well as possible strontium isotope dating are required. neither rudists nor microfossil benthic assemblages allow (at least not according to our present knowledge) greater stratigraphic resolution within carbonate platform domains of this age. acknowledgements this paper is a result of comprehensive geological investigations by the “adriatic team” of the institute of geology in zagreb, supported by the ministry of science and technology of the republic of croatia through the project no. 0181–0101: geological map of the republic of croatia (scale 1:50.000). we wish to thank ladislav fuček who introduced us to the geology of the island of cres. the help in microfossil and rudist determinations by ivo velić and boško korolija is greatly appreciated. we acknowledge our colleagues nenad oštrić, božo prtoljan and igor vlahović for their valuable suggestions and support during the fieldwork. finally, we are grateful to ivan gušić, josip tišljar and peter w. skelton for very useful suggestions that greatly improved the manuscript. 5. references bilotte, m. (1984): les grands foraminifères benthiques du crétacé pyrénéen. biostratigraphie. réflexion sur les corrélations mésogéennes [larger benthic foraminifera from the pyreneean upper cretaceous: biostratigraphy. thoughts on the mesogean correlations – in french].– benthos ’83, 2nd int. symp. benthic foraminifera (pau, april 1983), 61–67. bilotte, m. (1986): le crétacé supérieur des plates-formes est-pyrenéenes [upper cretaceous of east pyreneean platforms – in french].– strata, 2/5, 1–438. caffau, m. (1999): stop 2: evidence of regresion in the late turonian at slivia (trieste karst, italy).– in: höfling, r. & steuber, t. (eds.): fifth international congress on rudist – abstract and field trip guide. erlangener geologische abhandlungen, 3, 138–143. carannante, g., ruberti, d. & sirna, m. (2000): upper cretaceous ramp limestones from the sorrento peninsula (southern apennines, italy): microand macrofossil associations and their significance in the depositional sequences.– sedimentary geology, 132, 89–123. cestari, r. & sartorio, d. (1995): rudist and facies of the periadriatic domain.– agip spec. public., 207 p. cestari, r., pons, j.m. & sirna, g. (1996): redescription of vaccinites fortisi (catullo, 1834).– revista mexicana de ciencias geológicas, 12/2 (1995), 169–178. chiocchini, m., farinacci, a., mancinelli, a., molinari, v. & potetti, m. (1994): biostratigrafia a foraminiferi, dasicladali e calpionelle delle successioni carbonatiche mesozoiche dell’appennino centrale (italia) [mesozoic biostratigraphy of foraminifera, dasycladales and calpionelles of the central apennines (italy) – in italian].– studi geol. camerti, vol. spec. a, biostratigrafia dell’italia centrale, 9–128. cucchi, f., pirini radrizzani, c. & pugliese, n. (1989): the carbonate stratigraphic sequence of the karst of trieste (italy).– mem. soc. geol. ital., 40 (1987), 35–44. davey, s.d. & jenkyns, h.c. (1999): carbon-isotope stratigraphy of shallow-water limestones and implications for the timing of late cretaceous sea-level rise and anoxic events (cenomanian–turonian of the peri-adriatic carbonate platform, croatia).– eclogae geol. helv., 92, 163–170. de castro, p. (1966): sulla presenza di un nuovo genere di endothyridae nel cretacico superiore della campania [on the presence of new genus of endothyridae in the upper cretaceous of campania – in italian].– boll. soc. nat. napoli, 75, 317–347. de castro, p. (1971): osservazioni su raadshovenia van den bold i suoi rapporti col nuovo genere scandonea (foraminiferida, miliolacea) [observations on raadshovenia van den bold and its relationship to the new genus scandonea (foraminiferida, miliolacea) – in italian].– boll. soc. nat. napoli, 80, 1–78. dechaseaux, c. & coogan, a.h. (1969): systematic descriptions, hippuritidae gray.– in: moore, r.c. (ed.): treatise on invertebrate pelaeontology. part n. mollusca 6/2, geol. soc. am. & university of kansas, 799–803. douvillé, h. (1890–94): études sur les rudistes – révision des principales espèces d’hippurites [studies on rudists – revision of principal hippuritid species – in french].– mém. soc. géol. france, 6/1–4, 138 p. fleury, j.j. (1980): les zones du gavrovo–tripolitza et du pinde–olonos (grèce continentale et péloponnèse du nord). évolution d’une plate-forme et d’un bassin dans leur cadre alpin [gavrovo-tripoli and pinde-olonos zones 180 geologia croatica 56/2 181korbar & husinec: biostratigraphy of turonian to (?)coniacian platform carbonates... (continental greece and north peleponnese). evolution of platform and basin within its alpine development – in french].– thèse sc. nat., villeneuve d’ascq, 651 p. fuček, l., gušić, i., jelaska, v., korolija, b. & oštrić, n. (1990): stratigrafija gornjokrednih naslaga jugoistočnog dijela dugog otoka i njihova korelacija s istovremenim naslagama otoka brača (upper cretaceous stratigraphy of the se part of dugi otok island and its correlation with the corresponding deposits of the brač island, adriatic carbonate platform).– geol. vjesnik, 43, 23–33. fuček, l., jelaska, v., gušić, i., prtoljan, b. & oštrić, n. (1991): padinski turonski sedimenti uvale brbišnica na dugom otoku (turonian slope deposits in the brbišnica cove, dugi otok island, croatia).– geol. vjesnik, 44, 55–67. fuček, l., velić, i., vlahović, i., oštrić, n., korolija, b. & matičec, d. (1995): novi podaci o stratigrafiji donje krede otoka cresa [new data on the lower cretaceous stratigraphy of the island of cres – in croatian].– in: vlahović, i., velić, i. & šparica, m. (eds.): 1. hrvatski geološki kongres (the first croatian geological congress), opatija 1995, zbornik radova (proceedings), 1, institut za geološka istraživanja (institute of geology), zagreb, 167–172. gendrot, c. (1968): stratigraphie et micropaléontologie du sénonien de la région de martigues près marseille (bouches-du-rhône) [stratigraphy and micropaleontology in the senonian of martigues area near marseille (bouches-du-rhône) – in french].– eclog. geol. helv., 61/2, 657–694. glovacki jernej, ž. & jelaska, v. (1986): gornjokredni facijes otoka brača (upper cretaceous facies of the island of brač).– xi kongres geologa jugoslavije, 2, tara, 217–228. gušić, i. & jelaska, v. (1990): stratigrafija gornjokrednih naslaga otoka brača u okviru geodinamske evolucije jadranske karbonatne platforme (upper cretaceous stratigraphy of the island of brač within the geodynamic evolution of the adriatic carbonate platform).– djela jugoslavenske akademije znanosti i umjetnosti, 69, institut za geološka istraživanja, zagreb, 160 p. gušić, i. & jelaska, v. (1993): upper cenomanian– lower turonian sea-level rise and its consequences on the adriatic–dinaric carbonate platform.– geol. rundschau, 82/4, 676–686. gušić, i., jelaska, v. & velić, i. (1988): foraminiferal assemblages, facies, and environments in the upper cretaceous of the island of brač, yugoslavia.– rev. paléobiol., 2, benthos ’86, 447–456. hardenbol, j., thierry, j., farley, m.b., jacquin, t., de graciansky, p.-c. & vail, p.r. (1998): chart 5 – cretaceous biochronostratigraphy.– in: de graciansky, p.-c., hardenbol, j., jacquin, t. & vail, p.r. (eds.): mesozoic and cenozoic sequence stratigraphy of european basins. soc. econ. paleont. mineral., spec. publ., 60, 786 p. husinec, a. (2001): palorbitolina lenticularis from the northern adriatic region: palaeogeographical and evolutionary implications.– journal of foraminiferal research, 31/4, 287–293. husinec, a., velić, i., fuček, l., vlahović, i., matičec, d., oštrić, n. & korbar, t. (2000): mid cretaceous orbitolinid (foraminiferida) record from the islands of cres and lošinj (croatia) and its regional stratigraphic correlation.– cretaceous research, 21/1, 155–171. jelaska, v., gušić, i., jurkovšek, b., ogorelec, b., ćosović, v., šribar, l. & toman, m. (1994): the upper cretaceous geodynamic evolution of the adriatic–dinaric carbonate platform(s).– géologie méditerranéenne, 21/3–4, 89–91. jenkyns, h.c. (1991): impact of cretaceous sea level rise and anoxic events on the mesozoic carbonate platform of yugoslavia.– amer. ass. petrol. geol. bull., 75/6, 1007–1017. jurkovšek, b., toman, m., ogorelec, b., šribar, l., drobne, k., poljak, m. & šribar, l. (1996): formacijska geološka karta južnega dela tržaško– komenske planote. kredne in paleogenske karbonatne kamnine. 1:50000 (geological map of the southern part of the trieste–komen plateau. cretaceous and paleogene carbonate rocks).– inšt. geol., geoteh. in geofiz., ljubljana, 143 p. korbar, t. (1999): dinamika taložnih okoliša i razvoj rudistnih zajednica u cenomanu otoka cresa (dynamics of sedimentary environments and development of rudist communities in the cenomanian of cres island–adriatic sea, croatia – in croatian with english summary).– unpubl. msc thesis, university of zagreb, 74 p. korbar, t. (2003): stratigrafija, taksonomija i paleoekologija radiolitida gornje krede jadranske karbonatne platforme (stratigraphy, taxonomy and palaeoecology of upper cretaceous radiolitidae of the adriatic carbonate platform – in croatian with english summary).– unpubl. phd thesis, university of zagreb, 242 p. korbar, t. & husinec, a. (2002): biostratigraphy of turonian to (?)coniacian shallow-water carbonate succession on the island of cres, northern adriatic, croatia.– in: vlahović, i. & korbar, t. (eds.): 6th international congress on rudists, rovinj, abstracts and excursion guidebook, institute of geology, zagreb, 32–33. korbar, t., fuček, l., husinec, a., vlahović, i., oštrić, n., matičec, d. & jelaska, v. (2001): cenomanian carbonate facies and rudists along shallow intraplatform basin margin – the island of cres (adriatic sea, croatia).– facies, 45, 39–58. loeblich, a.r., jr. & tappan, h. (1988): foraminiferal genera and their classification.– van nostrand reinhold, 970 p. magaš, n. (1968): osnovna geološka karta sfrj 1:100.000, list cres, l33–113 (basic geological map of sfry. the cres sheet).– institut za geološka istraživanja, zagreb (1965), savezni geološki zavod, beograd. mamužić, p. (1968): osnovna geološka karta sfrj 1:100.000. list lošinj l33–125 (basic geological map of sfry. the lošinj sheet).– institut za geološka istraživanja, zagreb (1959–1965), savezni geološki zavod, beograd. mamužić, p., polšak, a., grimani, m. & magaš, n. (1976): biostratigrafske i litofacijelne karakteristike 180 geologia croatica 56/2 181korbar & husinec: biostratigraphy of turonian to (?)coniacian platform carbonates... gornje krede sjeveroistočnih padina biokova u južnoj hrvatskoj (biostratigraphic and lithofacial characteristics of upper cretaceous northeastern slopes of biokovo in southern croatia).– viii jugoslovanski geološki kongres, 2, ljubljana, 167–180. mamužić, p., polšak, a., grimani, m. & korolija, b. (1982): geološki stup kroz naslage cenomana i donjeg turona u središnjem dijelu otoka cresa (une colone stratigraphique á travers les couches du cénomanien et du turonien inférieur dans la partie centrale de l’île de cres) [geological column of cenomanian and lower turonian deposits on the central part of the island of cres – in croatian with french abstract].– geol. vjesnik, 35, 65–70. moro, a. (1997): stratigraphy and paleoenvironments of rudist biostromes in the upper cretaceous (turonian– upper santonian) limestones of southern istria, croatia.– palaeogeography, palaeoclimatology, palaeoecology, 131, 113–131. moro, a. & jelaska, v. (1994): upper cretaceous peritidal deposits of olib and ist islands (adriatic sea, croatia).– geol. croatica, 47/1, 53–65. moro, a., skelton, p.w. & ćosović, v. (2002): palaeoenvironmental setting of rudists in the upper cretaceous (turonian–maastrichtian) adriatic carbonate platform (croatia), based on sequence stratigraphy.– cretaceous research, 23, 489–508. philip, j. (1998): biostratigraphie et paléobiogéographie des rudistes: évolution des concepts et progrés récents [biostratigraphy and palaeobiogeography of rudists: evolution of concepts and recent progress – in french].– bull. soc. géol. france, 169/5, 689–708. platel, j-p. (1998): the turonian rudist-bearing carbonate platforms of the charentes and périgord areas, aquitaine basin (france).– in: masse, j-p. & skelton, p.w. (eds.): quatrième congrès international sur les rudistes, geobios mém. spéc., 22, 295–311. polšak, a. (1965): geologija južne istre s osobitim obzirom na biostratigrafiju krednih naslaga (géologie de l’istrie méridionale spécialements par repport é la biostratigraphie des couches crétacées) [geology of southern istria with particular attention to cretaceous biostratigraphy – in croatian with french abstract].– geol. vjesnik, 18/2, 415–510. polšak, a. (1967a): osnovna geološka karta sfrj 1:100.000. list pula l33–112 (basic geological map of sfry. the pula sheet).– institut za geološka istraživanja, zagreb (1963), savezni geološki zavod, beograd. polšak, a. (1967b): kredna makrofauna južne istre (macrofaune crétacée de l’istrie méridionale, yugoslavie) [cretaceous macrofauna of southern istria – in croatian with french abstract].– palaeont. jugoslavica, 8, 219 p. polšak, a. & mamužić, p. (1969): nova nalazišta rudista u gornjoj kredi vanjskih dinarida (les nouveaux gisements de rudistes dans le crétacé supérior des dinarides externes) [new findings of rudists within upper cretaceous of the external dinarides – in croatian with french abstract].– geol. vjesnik, 22, 229–245. polšak, a., bauer, v. & slišković, t. (1982): stratigraphie du crétacé supérior de la plate-forme carbonatée dans les dinarides externes [upper cretaceous stratigraphy of carbonate platform of the external dinarides – in french].– cretaceous research, 3, 125– 133. ross, d.j. & skelton, p.w. (1993): rudist formations of the cretaceous: a palaeoecological, sedimentological and stratigraphical review.– sedimentol. rev., 1, 73–91. sánchez, v. (1981): hippuritidae y radiolitidae (bivalvia). catalogo de especies [hippuritidae and radiolitidae (bivalvia). species catalog – in spanish].– universidad autonoma de barcelona, publicaciones de geologia, 15, 228 p. simonpiétri, g. (1999): systématique, phylogenèse, ontogenèse chez les hippuritidae (rudistes du crétacé supérieur) [systematics, phylogenesis, ontogenesis of hippuritidae (upper cretaceous rudists) – in french].– thèse, université de provence, 181. skelton, p.w. (1978): the evolution of functional design in rudists (hippuritacea) and its taxonomic implications.– philosophical transactions of the royal society of london, series b, 284, 305–318. skelton, p.w. & gili, e. (1991): palaeoecological classification of rudist morphotypes.– in: sladić-trifunović, m. (ed.): first international conference on rudists, october 1988, proceedings, 71–86, serbian geological society, belgrade (issued only as a reprint from unpublished volume; paper resubmitted elsewhere for publication). skelton, p.w. & smith, a.b. (2000): a preliminary phylogeny of rudist bivalves.– in: harper, e.m., taylor, j.d. & crame, j.a. (eds.), the evolutionary biology of the bivalvia, geological society (london), special publication, 177, 97–127. slišković, t. (1968): biostratigrafija gornje krede južne hercegovine [upper cretaceous biostratigraphy of southern herzegovina – in croatian].– glasnik zemaljskog muzeja bosne i hercegovine, prirodne nauke, 13, 23–51. steuber, t. (1999a): cretaceous rudist of beotia, central greece.– special papers in palaeontology, 61, 226 p. steuber, t. (1999b): microevolution in the hippuritidae – evidence from morphometric analyses and strontium isotope stratigraphy.– in: höfling, r. & steuber, t. (eds.): fifth international congress on rudist – abstract and field trip guide, erlangener geologische abhandlungen, 3, 69–70. steuber, t. (1999c): a palaeontological database of rudist bivalves (mollusca, hippuritoidea, gray 1848): taxonomic database.– website: http://www. ruhr-unibochum.de/sediment/rudinet/intro.htm. steuber, t. (2001): strontium isotope stratigraphy of turonian–campanian gosau-type rudist formations in the northern calcareous and central alps (austria and germany).– cretaceous research, 22, 429–441. steuber, t. & höfling, r. (1999): strontium isotope stratigraphy of lower gosau subgroup rudist formations in the northern calcareous alps.– in: höfling, r. & steuber, t. (eds.): fifth international congress on rudist – abstract and field trip guide. erlangener geologische abhandlungen, 3, 108–113. 182 geologia croatica 56/2 183 stössel, i. & bernoulli, d. (2000): rudist lithosome development on the maiella carbonate platform margin.– in: insalaco, e., skelton, p.w. & palmer, t.j (eds.): carbonate platform systems: components and interactions. geological society, london, spec. publ., 178, 177–190. šikić, d., polšak, a. & magaš, n. (1969): osnovna geološka karta sfrj 1:100.000. list labin l33–101 (basic geological map of sfrj. the labin sheet).– institut za geološka istraživanja, zagreb (1967), savezni geološki zavod, beograd. tentor, m., tunis, g. & venturini, s. (1994): schema stratigrafico e tettonico del carso insontino [stratigraphical and tectonical scheme of insontiono karst – in italian].– natura nascosta, 9, 1–32. toucas, a. (1903–04): études sur la classification et l’évolution des hippurites [studies on classification and evolution of hippurites – in french].– mém. soc. géol. france, 30/11–12, 128 p. velić, i. (1973): stratigrafija krednih naslaga u graničnom području velike i male kapele (stratigraphy of the cretaceous deposits in the border region of velika kapela and mala kapela mountains, central croatia).– geološki vjesnik, 26, 93–110. velić, i., sokač, b. & galović, i. (1980): tektonsko i paleogeografsko značenje novih nalaza senonskih vapnenaca i eocenskog fliša u kordunu, središnja hrvatska (tectonic and paleogeographic significance of new discoveries of senonian limestones and eocene flysch in kordun, central croatia).– geološki vjesnik, 31, 191–202. vlahović, i., korbar, t., moro, a., velić, i., skelton, p.w., fuček, l. & tišljar, j. (2002): latest cenomanian to earliest turonian platform drowning and turonian recovery of shallow-water platform deposition in southern istria.– in: vlahović, i. & korbar, t. (eds.), 6th international congress on rudists, rovinj, abstracts and excursion guidebook, institute of geology, zagreb, 123–127. manuscript received january 21, 2003. revised manuscript accepted november 04, 2003. plate i shallow-water carbonates and rudists from the island of cres 1 thick-bedded peritidal limestones. lower part of the martinšćica section. turonian to (?)coniacian. 2 hippurites cf. resectus defrance, sample cmb. upper part of the martinšćica section. turonian to (?)coniacian. 3 hippurites cf. resectus defrance, sample cn–864c. turonian to (?)coniacian. 4 radiolitid thicket (biostrome) at the top of a thick bed of peritidal limestone. central part of the martinšćica section. turonian to (?)coniacian. 5 hippurites cf. resectus defrance, sample cn–864. turonian to (?)coniacian. 6 hippurites cf. resectus defrance, sample cn–953. turonian to (?)coniacian. 7 hippurites cf. resectus defrance, sample cn–864d. turonian to (?)coniacian. 8 hippurites cf. resectus defrance, sample cl–1195. turonian to (?)coniacian. 182 geologia croatica 56/2 183 1 4 76 8 5 3 2 korbar & husinec plate i 184 geologia croatica 56/2 185 plate ii microfossils from the martinšćica section (see fig. 2). 1 moncharmontia apenninica de castro, sample cma–7, 70x. turonian to (?)coniacian. 2 pseudocyclammina sphaeroidea gendrot, sample cma–5, 55x. turonian to (?)coniacian. 3, 4 scandonea samnitica de castro, samples cma–5 (3) and cma–3 (4), 55x. turonian to (?)coniacian. 5, 6 aeolisaccus kotori radoičić – thaumatoporella parvovesiculifera (raineri) wackestone, sample cma–9, 55x. turonian to (?)coniacian. 184 geologia croatica 56/2 185 1 2 3 4 65 korbar & husinec plate ii 186 geologia croatica 56/2 jurak et al.indd verification of engineering-geological/geotechnical correlation column and reference level of correlation (rnk) method by observations in the slip-plane zone vladimir jurak1, želimir ortolan2, dragutin slovenec1 and zlatko mihalinec3 1. introduction when presenting results obtained during study of a landslide situated in the stiff and fractured diluvial clay in the zone of prekrižje in zagreb, nonveiller (1964) indicated that the low thickness of the sliding zone (from 1 to 10 mm) was established as late as in the course of subsequent observations made during improvement work. the zone is in fact composed of a very thin intercalation of light gray or bluish clay of high plasticity (ch), which was not discovered during the initial drilling operations. while describing the assumed sliding mechanism and results of stability analyses, he claimed that the shear strength of the lowest-strength material component is in fact relevant as a proof of slope safety. over several past decades, such observations have proven to be quite useful and have served as guidance to many investigators all over the world in their efforts to explore this idea in greater detail. furthermore, fully aware of the complexity of slope stability investigations and of the need to establish close cooperation between engineering geologists and geotechnical engineers, nonveiller (1979, p. 402) states: “extensive research has shown that geological details that at first appear to be of secondary significance, are sometimes crucial for the stability and development of landslides on slopes, and may hence be relevant for safety calculations. today, it is evident that such phenomena, occurring in the very complex geological medium of the earth’s crust, can not be considered separately, i.e. as a purely mechanical phenomenon”. the aim of precise engineering-geological and/or geotechnical modelling of relatively well-bedded media (soft rocks and all types of soil) is to establish complete correlation of formations i.e. to create a logical vertical sequence (engineering-geological and/or geotechnical correlation column) in which the lateral persistence of “layers” (and even very thin laminae) of uniform geotechnical properties can also be established. the detailed correlation of formations (in geological sciences by normal mapping “from layer to layer”) has revealed (ortolan, 1990, 1996, 2000) that all geotechnical results (obtained both in situ and in the laboratory) may be interpolated, in zones of geologia croatica 57/2 191–203 17 figs. 2 tabs. zagreb 2004 key words: plasticity index, shear strength, engineering-geological/geotechnical correlation column, rnk-method, slope stability, landslide. 1 faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, hr-10000 zagreb, croatia; e-mail: vjurak@rgn.hr 2 rnk – geomod d.o.o., joze laurenčića 18/iii, hr-10000 zagreb, croatia. 3 civil engineering institute of croatia, janka rakuše 1, hr-10000 zagreb, croatia. abstract the engineering-geological/geotechnical correlation column can be established in zones of limited extent using one or several characteristic layers, one of which is selected as the reference layer. the reference level of correlation method, i.e. the rnk (referentni nivo korelacije in croatian) method, is a confirmed procedure enabling the establishment of such columns. in the engineering geological/ geotechnical correlation column, the plasticity index is the most significant indicator of the peak friction angle, full-softening friction angle and residual friction angle for coherent soils and soft rock formations. as a rule, maximum plasticity index values correspond to the minimum values of such friction angles. this opens up the possibility of an exact engineering-geological/geotechnical model, with accurate differentiation of minimum shear strength zones, zones of different permeability, and zones of various degrees of natural compaction. this procedure was applied inter alia on the successfully improved granice landslide located in the zagreb area, where it was proven that elements for verification based on the rnk-method exist for all three areas of investigation: sliding body – drain trench section – detail in the central portion of the sliding zone. the procedure is recommended as a means for finding solutions to similar problems. 192 geologia croatica 57/2 193jurak et al.: verification of engineering-geological/geotechnical correlation... limited extent characterized by relative lithological homogeneity, into the appropriate part of a vertical sequence within the geotechnical correlation column, both in flat and inclined types of terrain. this is obtained by one or several characteristic layers, one of which is then selected as a reference layer. ortolan (1996) named this a reference level of correlation (rnk – referentni nivo korelacije in croatian). here the emphasis is placed on the existence of one plane or a very thin but widely spread zone, which becomes crucial for all other harmonisation with this recognizable level. the selection of the above mentioned name may be explained by analogy with the definition for the reference level (niveau surface) in mathematics (theory of fields), geophysics and geodesy. in addition, this level or thin zone also alludes to the notion of a reference horizon. a series of novel procedures was developed in the scope of the thesis (ortolan, 1996) using the podsused landslide in zagreb as an example. strict application of such procedures in the engineering geological and/or geotechnical modelling has become known as the reference level of correlation method (rnk-method). the task of establishing a spatial engineeringgeological/geotechnical model of a landslide may prove to be extremely delicate and complex, particularly in the case of deep multilayered landslides. in this respect, the following features must be defined with sufficient accuracy: geometry of sliding bodies, pore pressures along slip planes, and shear resistance parameters along zones with minimum shear strength materials. here, our attention is focused on the well known granice landslide in zagreb or, more precisely, on the segment that is of crucial significance for the accurate geotechnical modelling of landslides: the establishment and verification of the engineering-geological and/or geotechnical correlation column. this example is particularly interesting because investigations and analyses were carried out by experts from various complementary disciplines and professions and, in the end, the landslide was successfully improved. 2. rnk method – fundamental notions and basic definitions the plasticity index has proven to be a reliable strength indicator for coherent materials (ortolan, 1996; ortolan & mihalinec, 1998). therefore, testing of atterberg plasticity limits on point samples can reasonably be recommended for the identification of minimum shear strength zones. the sampling interval should not exceed 10 cm (sometimes it should be as little as several cm, and even several mm). however, sampling at every 0.5–1.0 m interval, always based on professional judgment, is generally considered sufficient. a diagram, usable in practice and showing correlation between the residual and peak friction angle and plasticity index, was proposed by ortolan & mihalinec (1998). the rnk-method or the reference level of correlation method (ortolan, 1996) is a fully developed method for engineering-geological and/or geotechnical modelling. it is primarily destined for analysis of the slope stability of soils and soft rock formations. the rnk (reference level of correlation) is defined as an unequivocally recognizable and visually identifiable (or graphically defined) bedding plane or any other reference plane within a structural feature, in relation to which the altitude of all studied profiles can be unambiguously defined, with individual point analysis of any material property. such a plane is a part of a single vertical lithostratigraphic, i.e. engineering geological and/or geotechnical sequence (engineeringgeological and/or geotechnical correlation column). in the rnk-method, we mostly use visually recognizable layers, i.e. layers of striking colour and exceptionally high or low plasticity with respect to the underlying and overlying strata, or layers that are markedly fossiliferous, layers with marked grading, with high organic matter content, or layers characterized by some other distinguishing feature. however, the presence of visually recognizable reference layers is not a requirement. in case of lithological monotony, the position of the rnk may be defined at will by means of a graphical procedure, provided that there is a sufficient density of laboratory results (plasticity index). the procedure is carried out in such a way that results (obtained by laboratory testing of samples from boreholes, trial pits or outcrops) having at least one joint portion in a vertical sequence of layers, are drawn on oleates shown on the same scale (e.g. plasticity indices by depth). after that, oleates from individual boreholes (neighbouring boreholes must go through at least one part of the same package of formations) are overlapped so that test results are brought into a coincident position (position of maximum conformance) for portions of the same packages of formations. the rnk is defined at an oleate selected at will, and then the rnk defined in this way is transferred to the coincident positions of the remaining boreholes. once the rnk depths are defined for every borehole, the results are united into a geotechnical correlation column. if we have the rnk position with at least three neighbouring boreholes of different extent, then the position of zones or layers may be determined by defining the plane with three points. local deviations of layer positions between neighbouring boreholes can also be defined. the geotechnical correlation column is a consistent engineering-geological and/or geotechnical soil model (design cross section) in which adequate parameters (defined in the laboratory or in situ, either by the point method or continuously), can reasonably be allocated to every defined layer (and portions of such layers) along the entire height of the vertical 192 geologia croatica 57/2 193jurak et al.: verification of engineering-geological/geotechnical correlation... sequence of formations covered by the study. from such a geotechnical correlation column we may in principle differentiate zones of minimum residual shear resistance, with their thicknesses and continuities, and also layers with different moisture, permeability, natural compaction, compressibility, etc. the engineeringgeological and/or geotechnical correlation column of an analyzed area is the “key” to the interpretation of the overall engineering-geological and/or geotechnical relationships in a required number of profiles selected at will for 2d and spatial analysis, which is especially significant in 3d analysis of stability. the following supporting documents are most often used in the study of landslides: general geological map of the wider area under study, geotechnical correlation column, engineering-geological map with slip-plane contour lines and with clearly delineated slip areas and hydro-isohypses or hydro-isopiestic lines at the slip-plane level (ortolan, 1996, 2000). previous definition of such features is the guarantee that the highest possible level of accuracy will be attained in the resolution of slip problems and/or in the definition of crucial slope safety factors. such supporting documents provide all relevant information needed to develop a series of representative detailed profiles which is in turn indispensable in the three-dimensional stability analyses of slopes. such documents were also provided for the granice landslide which is presented below as a case study. 3. results obtained by the rnk-method the consistent use of the rnk-method in the period from 1995 to the present day has resulted in the elaboration of three-dimensional geotechnical models for some thirty landslides. in all of these cases the following parameters were successfully defined: sliding body geometry, pore pressures along slip-planes, and shear strength parameters for materials along zones of minimum shear resistance. in combination with existing topographical documents, this enabled accurate stability analyses and definition of optimum improvement procedures. the podsused landslide may be described as one of the most complex urban landslide projects in the world (ortolan, 1996, 2000). it is precisely on this project that the rnk-method has been developed in full detail, and the reliability of the model was confirmed with photogrammetry measurements (ortolan & pleško, 1992; ortolan et al., 1995) as well as with three-dimensional stability analyses (mihalinec & stanić, 1991; stanić & nonveiller, 1996). as it meets all the relevant criteria (jurak et al., 1996) it has been proposed for insertion in the wli (world landslide inventory). most of the studied landslides have been improved, in all cases with great success, and the supervisory work conducted during realization of improvement activities provided positive feedback information about the correctness of the adopted engineering-geological and/or geotechnical landslide models (e.g. at the frkanovec landslide near čakovec and at the granice landslide), and about reliability of the engineering-geological and/or geotechnical correlation column (design cross section). on some projects, such as the čiritež landslide in istria and črešnjevec landslide in zagreb, the reliability of the model was checked and confirmed by appropriate auscultation equipment: inclinometers, piezometers and benchmarks. on these landslide projects, inclinometer movements were registered at depths that corresponded well with forecast values obtained on the basis of the rnk-method. landslide models were also confirmed by new samples taken during installation of auscultation equipment, e.g. on the granice and črešnjevec landslide projects. these samples were tested in the laboratory in order to establish new geotechnical correlation columns, but this effort only confirmed the model that had previously been accepted. in the case of the črešnjevec landslide, the validity of the model was additionally confirmed by deep excavation for a water reservoir in the vicinity of the landslide. in fact, a number of samples were taken from the foundation pit and tested in the laboratory, and the results have shown good correspondence with the previously established geotechnical correlation column. interpolation of the results obtained by samples from boreholes for installation of additional auscultation equipment, into the already prepared geotechnical correlation column was similar. 4. verification of the engineeringgeological/geotechnical correlation column and rnk-method on the granice landslide project in zagreb one of the ways for checking the reliability of the engineering-geological and/or geotechnical column is presented using the granice landslide in zagreb as an example. here, the validity of the geotechnical correlation column and three-dimensional sliding model was assesed by continuous monitoring during the realization of drain trenches, using three generations of samples that were systematically taken and tested in the laboratory. according to observations made by nonveiller (1964, 1979), special emphasis was placed on the study of “geological details seemingly of secondary significance”. results of these investigations and verification of the engineering-geological and/or geotechnical correlation column, all point to the high accuracy of the rnk-method, and are presented in the following section. 4.1. properties of materials found in the landslide during the first investigation of 1995 the objective of the first investigative campaign conducted in 1995 was to establish a geotechnical report with a landslide improvement proposal. a general layout for 194 geologia croatica 57/2 195jurak et al.: verification of engineering-geological/geotechnical correlation... the landslide is presented in fig. 1. the topographic presentation of the neighbouring terrain with the contour of the landslide is given in fig. 2. it can be seen that the landslide was activated on the plateau, slightly sloping (no more than 5°) from north to south, which is also the slip direction. the first geotechnical correlation column of the landslide was prepared by graphical procedure, i.e. by the overlapping of oleates. a portion of this column, with the geological and ac classification of materials, is presented in fig. 3. formations found on the landslide date back to the upper pontian (rhomboidea layers) and are characterized by their pronounced laminar texture. the formations slope slightly towards the southeast, and the slip-plane generally coincides with the position of the layers. samples from all three generations (1995, may and august 1998) are presented on the plasticity chart (fig. 4) where they are classified on their plasticity according to the bscs (british soil classification system – bsi, 1981; iaeg, 1981). here, attention is drawn to the group of clay samples characterized by very high plasticity (cv) which is often typical for materials of pronounced colloidal activity and high expansivity. it is precisely these samples that come from the slip zone proper, about 10 cm in total thickness. results of laboratory and in situ investigations, presented in the form of a single geotechnical correlation column, are given in fig. 5. the situation is very indicative and leaves little doubt as to the position of the slip-plane. in fact, several indicators are normally considered significant for the detection of potential slip-planes. three such indicators are taken into account in our case: quantity of clay particles (<2 μm in size, ≥30%; coinciding with a reduction in the sand component), plasticity index (pi) as a derived variable (≥50%) and natural compaction level of the soil. in the interval presented in fig. 5, the first two indicators show two very pronounced and coinciding “peaks” (which are in firm logical correlation to one another) at the same level. this clearly points to a weakening in the geotechnical correlation column and to the possible formation of a mechanical discontinuity. the third indicator (natural compaction or relative density) is indicative only in particular cases. here we may say that it is indicative only to a certain extent, as a significant increase in the degree of compaction actually occurs below the slip-plane level. however, all the information points to a particular plane and to the following reference level of correlation: rnk=kp=0 (fig. 5). the consistency state known as material “remolding” may partly be caused by significant displacements (total displacements of about 10 m were registered at the granice landslide). however, this state should not be considered as definite evidence of the slipplane position. in fact, displacements amounting to several metres were registered along slip-planes in the case of the podsused landslide but the occurrence of “remolding” was not registered at any of the three slipplanes (ortolan, 1996). it would be more plausible to explain the contrasts in the compaction level of materials through the history of terrain formation, including diagenesis. of course, the position of slipplanes at the contact of contrasting features may also be purely coincidental. in this respect, it may be noted that the “zagreb terrace” sediments, dating back to the pleistocene, are lacking in the case of the granice landslide as they were probably lost due to erosion. slope wash sediments i.e. colluvium (cf. fig. 3) dating back to the early quaternary period (pebbles and poorly rounded fragments of quartz and rocks from medvednica mountain, and frequent remains of vegetable matter) occur directly above the upper pontonian layers. these sediments were not (or at least not considerably) compressed with a thick overburden, nor are there any indications of the onset of lithification, which is why the natural compaction level is lower. fig. 1 general layout of the granice landslide with the coordinates of an approximate centre of gravity. fig. 2 granice landslide with the position of the steel pressure pipeline forming part of the municipal drinking water supply system, which was for many years endangered by landslide activity. 194 geologia croatica 57/2 195jurak et al.: verification of engineering-geological/geotechnical correlation... 4.2. data about landslide material gained by investigative campaigns undertaken in may and august 1998 the second campaign of systematic sampling in the narrow slip-plane zone was conducted during the realization of drain trenches protected with krings struts (in drain “6”; cf. drain position in fig. 2) on the occasion of field exercises for students of the faculty of mining, geology and petroleum engineering (may 7, 1998). at that time, a small cylindrical sample was taken in the immediate vicinity of the slip zone (fig. 6) and was then subjected to detailed testing. the third campaign of sampling and laboratory testing, related to the installation of inclinometers and piezometers, was conducted in august 1998. sample differentiation by grading, conducted in 1995 and 1998 (trench excavation for drain “6”) is presented in the triangular grading diagram (fig. 7). three groups of fine-grained materials can clearly be differentiated: silty sand (iii), clay (i) and a siltdominated mixture (ii). these groups are distributed as follows: silty sand is found in the continuous layer below the drain bottom, the silt-dominated mixture is equally distributed below and above the slip-plane, while samples with medium and high clay content (particles <2 μm) are either located in the slip-plane or in the zone immediately next to the slip-plane (about ten cm in thickness). the classification according to the content of clay size particles, i.e. low content (<20%) and high content (>40%) is based on a paper proposed by skempton (1985). the proportion of clay particles has a notable effect on the behaviour of the material. results obtained through determination of the plasticity index of clay samples during all three campaigns are presented in fig. 8. the hanging wall composed of fat clay layer of high plasticity, soft to firm, light-blue in colour (shown in fig. 3) was selected as the reference level of correlation (coinciding with the slip-plane position, i.e. rnk=sp) for the geotechnical correlation columns shown in figs. 5 and 8. it is believed that this fat clay layer belongs to the noneroded top portion of the upper pontian formations, although its genesis can also be explained differently, as indicated in the discussion. despite significant distances between individual sampling positions (often exceeding 100 m), all results fig. 3 geotechnical correlation column of the granice landslide (ortolan, 1996) established using the visually recognizable reference level of correlation. 196 geologia croatica 57/2 197jurak et al.: verification of engineering-geological/geotechnical correlation... fig. 4 plasticity chart for all three generations of samples from the granice landslide in zagreb which served for verification of the engineering geological/geotechnical correlation column and rnk method. the encircled zone contains samples from the slip-plane. fig. 5 geotechnical correlation column for the granice landslide (based on 1995 data). fig. 6 sampling in the immediate vicinity of the slip plane (kp) in drain “6” (photo by v. belošević, may 7, 1998). 196 geologia croatica 57/2 197jurak et al.: verification of engineering-geological/geotechnical correlation... point to good correspondence regarding the slip-plane position, which was quite accurately estimated in the geotechnical correlation column prepared in 1995 (ortolan, 1996), as well as being detected and confirmed by the continuous monitoring activities conducted during realization of subsequent landslide improvement work. results obtained by the determination of uniaxial compressive strength (by pocket penetrometer) and undrained shear strength (by light vane) in the slipplane proper during realization of drain trenches (in drain “6”; drain position is shown in fig. 2) are presented in fig. 9. the same figure shows the content of the clay fraction (particles <2 μm) as determined on the same samples that were used for the definition of the atterberg limits (plasticity indices are shown in fig. 5). fig. 9 also shows that the highest clay content was registered in the sample coming from the slipplane. the accuracy of the slip-plane position was also confirmed by uniaxial compressive and undrained shear strength values. of course, neither this, nor any other confirmation, can be considered significant in this case because the slip-plane position is clearly visible (fig. 6). however, if we were to look for the position of a potential slip-plane on a slope whose stability we have to determine, then each of the above details would of course have an appropriate weight. at this point, it would also be of interest to consider an obvious difference in the maximum content of the clay fraction, which can be seen by comparing fig. 5 (cf=32%) with fig. 9 (cf=53%). the difference is exclusively due to the use of different de-coagulants during the determination of grain size distribution. thus water glass was used on samples taken in 1995, while sodium hexametaphosphate was used during sampling performed in 1998. in fact, the sodium hexametaphosphate was introduced as standard only after 1995, i.e. after mulabdić et al. (1994) proved that the clay content may vary by up to 200–300%, depending on the previous preparation of soil samples for hydrometric analysis. samples prepared in this way would probably put an even greater emphasis on the grading differentiation shown in fig. 7. this is yet another proof of the claim about enrichment of a thin zone with clay particles, which has in fact oriented the reference level of correlation (rnk) precisely towards this lithological feature of the engineering-geological and/or geotechnical column. all this shows that the validity of the engineeringgeological and/or geotechnical correlation column has been confirmed on many occasions and in many ways, while also proving the correctness of basic notions of the rnk-method. the soundness of the method was also proven through stability analyses (ortolan, 1996) as the factor of safety fs≈1.0 had already been fig. 7 triangular grading diagram with grain size differentiation for samples taken in 1995 (cf. fig. 5) and those from drain trench “6”. samples (1) and (2) are from the cylinder shown in fig. 10 (detail a). fig. 8 verification of the geotechnical correlation column presented in fig. 5, based on the plasticity index from 1998 (samples from boreholes drilled for the installation of auscultation equipment and drain “6”). 198 geologia croatica 57/2 199jurak et al.: verification of engineering-geological/geotechnical correlation... obtained on the representative prognostic geotechnical profile during the initial iterations of calculations. such a level of accuracy was obtained on all projects on which the rnk-method has so far been used. 5. analysis of details in the slip-plane zone 5.1. sample physiography the study of details in the narrow slip-plane zone (and immediately above and below it), was undertaken in the second systematic sampling campaign conducted during realization of drain trenches (in the drain “6”). at that time, a small undisturbed sample was extracted with a metal cylinder (figs. 6 and 10). in this sample, the gray silty clay (1) can clearly be differentiated in the foot wall of the slip-plane and the yellow-brown sandy silt (2) in the hanging wall, with a contact lamina between them (3). the position of the slip-plane can clearly be observed in fig. 6 because, soon after excavation of a portion of the drain ditch, the material was displaced, at a level of 4.70 m, from the sliding body (yellow-brown – in hanging wall) and passed via stable sediments (gray – in foot wall) and along the slip-plane, due to the markedly softer consistence of material in the sliding body. in this segment, the slip-plane is also the limit plane. the sample extracted with the metal cylinder measuring 10 cm in length and 3.5 cm in diameter, was analyzed in detail using various methods and procedures, as shown below. blown up detail of the cylinder cross section given in fig. 10 is presented in fig. 11. the presence of macropores can be noted in the yellow-brown sandy silt. these macropores enable a more intensive flow of ground water, while also contributing to better redistribution of pore pressures along the sliding plane. they also bear witness to the transport of fine particles. 5.2. mineralogical and petrographical analyses the material contained in the extracted cylinder was analyzed by (a) optical microscopy, (b) scanning electron microscopy (sem) with an additional system for analysis in the energy-dispersive x-ray spectrum (edax), (c) by x-ray powder diffraction (xrd), and also included (d) determination of grading, and (e) chemical analyses. the yellow-brown material contained in one part of the sample was marked as “sample 2” while the gray material was marked as “sample 1”. the thin section was prepared in the zone perpendicular to the cylinder axis. the section included the contact between the yellow-brown and gray material (material 3 in figs. 10 and 12). the following materials were identified by petrographical analysis: 1) gray pelite–sandy silt; 2) limonitic sand of graywacke type; 3) contact lamina composed of sand of fine-grained filo-arenite type. as to the contact lamina in the cut zone, 2–3 mm in thickness, we should also take into account the mixing of particles from the foot wall and hanging wall, due to shear and displacement realized at the failure surface. it is known that the particle orientation and subparallel arrangement of grains occurs in the shear zone in accordance with the slip-plane (morgenstern & fig. 9 determination of uniaxial compressive strength, undrained shear strength and grading of material from drain “6” (detail a in figs. 3, 5, 8). fig. 10 cross-sectional photograph of the cylinder from fig. 6 (detail a: figs. 3, 5, 6, 8 and 9). shear stress zone is marked by arrows. a 198 geologia croatica 57/2 199jurak et al.: verification of engineering-geological/geotechnical correlation... tchalenko, 1967; mitchell, 1993 – fig. 8.23b, p. 151), as can be seen in fig. 12. the sem photomicrographs of yellow-brown and gray material are presented in figs. 13 and 14. minerals dominant in the yellow-brown material (2) are quartz and muscovite, and they range from 2 to 100 μm in size. the content of feldspars and goethite (grain size up to 40 μm) is also significant. very small chlorite sheets, up to 3 μm in diameter, can be found in the base, but also on bigger muscovite sheets. pores are up to 40 μm in width, and are partly filled with very small chlorite sheets. according to its composition, the gray material (1) is similar to the yellow-brown material, although its average grain size is much smaller and goethite particles are not present. pores up to 30 μm in width are mostly filled with very fine sheets of chlorite and sericite. the clay content is much higher than in the yellow-brown material. the grading analysis was conducted by wet sieving (particle fractions: >0.063 mm) and by sedimentation in cylinders (particle fractions: <0.063 mm) with na-pyrophosphate as a decoagulant. the graphical presentation of results, with cumulative grading curves, is given in fig. 15. it can be seen that the gray material (1) contains over 40 percent (by weight) of particles <2 μm, i.e. almost two times as much as the yellowbrown material (sample 2). according to the grading and mineralogical composition (table 2) the gray pelite sample (1) represents silty clay, while the yellow-brown sample (2) represents sandy silt. the amount of the main chemical components were determined by classic analysis, except for the na and k contents which were determined by flame photometry. the corresponding results are given in table 1. concentrations of exchangeable cations after leaching of the global samples with 2m ammonium acetate solution for two days were determined: na and k by flame emission spectrometry (fes), and ca, mg and ba by inductively coupled plasma and atomic emission spectrometry (icp – aes). the exchangeable cation concentrations (meq/ 100 g) are: ca=6.7, mg=5.5, na=0.9, k=0.8, ba=0.0 (sample 2); ca=1.6, mg=8.9, na=0.6, k=1.4, ba=0.1 (sample 1). according to these values, the cation exchange capacity (cec) amounts to 13.9 meq/100 g (sample 2) and 22.6 meq/100 g (sample 1). fig. 11 photograph of a detail from the rectangle shown in fig. 10 (x16). fig. 12 subparallel distribution of mineral grains along the slipplane (n+, x50) in contact lamina (3) from detail a. fig. 13 sem photomicrograph of the yellow-brown sandy silt. chlorite sheets are situated among muscovite, quartz and limonite (?). fig. 14 sem photomicrograph of the gray-coloured silty clay. clusters of fine flaky chlorite surrounded by quartz particles are quite frequent. 200 geologia croatica 57/2 201jurak et al.: verification of engineering-geological/geotechnical correlation... the mineral composition of the samples was determined by x-ray powder diffraction. diffraction patterns of non-oriented global samples were registered after the following treatments: (a) air drying, (b) glycerol solvation, (c) heating to 650°c for one hour, and (d) dissolution in hcl (1:1). diffraction patterns of oriented samples (isolated <1 μm particle fraction) were registered after the following treatments: (a) air drying and (b) treatment with ethylene glycol. the proportion of quartz, plagioclase, k-feldspar and goethite was determined by semi-quantitative x-ray analysis (external standard method). the mineral composition of the samples is shown in table 2. an approximate proportion of minerals in the samples was determined by harmonization of the x-ray, chemical analysis and cec data. it can be seen that samples from 10-å minerals, as well as the muscovite, also contain an illitic material. individual proportions of muscovite and illite could not be determined. for that reason, the sum of the proportions of these minerals is given in table 2. however, according to the diffraction patterns of the separated clay-size fraction (particles <2 μm), the illitic material is the most abundant clay component in both samples. quartz was not identified in the separated <1 μm particle fraction, which enabled x-ray identification of illitic material according to środoń (1984). characteristic parts of the x-ray diffraction patterns of this fraction, separated from both samples, are shown in fig. 16. according to środoń (1984), illitic materials from both samples are mixtures of pure illite and isii-ordered interstratified illite– smectite, which contains less than 15% of smectite layers. according to the data from table 2 and considering the proportion of particles smaller than 2 μm in which illitic material is dominant, it can be concluded that the low-permeability gray clay in powder (sample 1) contains much more typical clay minerals than the yellow-brown sandy silt (sample 2). it should furthermore be noted that a significant quantity of this mineral component, characterized by swelling (smectite), is present in the gray pelite sample. 6. discussion a possibility that the highly-plastic gray clay layer (ch) found in all boreholes realized in 1995 (fig. 3), as well as in subsequent boreholes, may be of different genesis is noted in section 4. there the thickness of this visible layer most often amounted to about 40 cm (i.e. it varied from 15 to 50 cm) while its thickness was about 10 cm in the drain trench (“6”). the slip-plane in contact with the hanging wall was registered on all occasions so that it is also a contact surface. as such, it was finally accepted as the reference level of correlation (rnk). in fact, it can be assumed that the primary enrichment with clay particles occurred during deposition of the rhomboidea layers, otherwise of pronouncedly laminated texture, which reduced the permeability in this horizon of the lithological column. thus the fig. 15 cumulative grading curves for the yellow-brown sandy silt (sample 2) and gray silty clay (sample 1) which are in contact along the slip-plane. chemical sample 1 sample 2 component (gray) (yellow-brown) sio2 59.22 65.95 tio2 0.28 0.35 al2o3 20.98 14.70 fe2o3* 4.15 6.90 mgo 2.65 1.65 cao 0.57 0.62 na2o 0.82 1.15 k2o 3.52 3.04 loi 6.60 4.84 h2o105 1.57 1.05 total 100.36 100.25 table 1 chemical composition of samples 1 and 2 (% by weight). *total fe content expressed as fe2o3. mineral sample 1 sample 2 (gray) (yellow-brown) quartz 23 38 plagioclase 4 8 k-feldspar 1 2 goethite – 5 muscovite 40 30 + illitic material smectite 12 5 chlorite 15 10 kaolinite 5 2 table 2 mineral composition of analyzed samples 1 and 2 (approximate weight %). 200 geologia croatica 57/2 201jurak et al.: verification of engineering-geological/geotechnical correlation... predisposition was created for the formation of the secondary argillic zone, as indicated by hristov (1974). environmental predispositions, i.e. relevant grading of the profile and hydrogeological circumstances, enabled subsequent enrichment with clay particles brought by water descending from the overburden. therefore, this is a continuous zone secondarily enriched with clay due to zonal differentiation of the soil crust due to weathering, which resulted in the formation of an argillic zone of gley type with spreading parallel to the surface of the terrain. perhaps it is precisely by its formation that the grading contrast is so pronounced at the contact with the hanging wall (figs. 10 and 11). as such, the zone has a specific hydrogeological and engineering-geological/geotechnical role. from the hydrogeological standpoint, it is a poorly permeable or almost impermeable layer, and in the engineeringgeological/geotechnical sense, it is a zone of minimum shear resistance in a relevant stress field. thus it can generally be described as a potential slip-plane, which was activated in the case under study. according to variable distribution (in this case it is a derived variable – plasticity index, l=ip) changing with the depth (fig. 17), we can clearly distinguish structural model elements of a stratified type (rac, 1973 – fig. 38, p. 129). in this case, this feature predetermines the landslide, which is of a translational type. the model presentation is valid for the sliding body in the rhomboidea layers. a general correspondence of the investigated properties is obvious, as shown in figs. 5 and 8, regardless of the distance in time and space. in the sliding zone, we obviously have clay of high to very high plasticity, and of minimum shear strength. it should be noted that some differences in the liquid limit and plasticity index values probably occurred due to the inadequate protection of samples against drying because, in fact, atterberg limits must be determined on naturally moist samples. if this is not the case, significant deviations may be expected as to the liquid limit and plasticity index values (results are much lower). some difference could also have occurred due to different levels of correctness during sample taking, because of the difference in drilling methods. the drilling made in 1995 was performed by hand augering with a pedological auger, while the drilling conducted in august 1998 was made by machine drilling with a single core barrel. obviously, in the case of machine drilling with a single core barrel the correctness of fig. 16 characteristic parts of the xrd patterns of samples with preferentially oriented particles of <1μm. fig. 17 structural model according to rac (1973) based on the variability of the selected indicator – plasticity index l=ip (not to scale, thickness relationships are relative). legend: 1, 3, 4 – mixture: sand, silt, clay (dominated by silt). quasihomogeneous media. 2 – continuous silty sand layer. 5 – secondary argillic zone – continuous layer of highly plastic clay. medium homogenized after sedimentation. kp – slip-plane. 202 geologia croatica 57/2 203jurak et al.: verification of engineering-geological/geotechnical correlation... sampling is higher, and the representativity of selected samples is better. when drilling is performed with a pedological auger, we are regularly faced with problems such as mixing with neighbouring soil layers and loss of information about the drilled interval. 7. conclusion in the study of landslides, stability levels of natural slopes, and artificially shaped slopes, unequivocal results can be obtained by the correlation of formations, and this by introducing the reference level of correlation (rnk-method) and by looking for the zone of minimum shear strength in the engineering-geological/ geotechnical correlation column through the plasticity index. properly verified examples fully confirm significance of establishing engineering-geological and/or geotechnical correlation columns, particularly in the case of smaller areas. however, this column can sometimes be established for zones occupying as much as several kilometres in area. the slip-plane positioning logic is confirmed by all segments and details studied in the scope of this analysis. when applied strictly and accurately, the methodology can be used widely under appropriate geological circumstances in soft rocks and in all types of soil. results obtained so far prove that the method is fully suitable for the preparation of exact engineering-geological and/or geotechnical models, and that such use of the method is highly recommended. its qualities are best manifested in the case of lithologically monotonous pelitic sediment profiles (silt and clay mixtures and their alternations) or in cases when the limits between individual formations are or cannot clearly be distinguished. the methodology has no sense if samples from longer intervals are selected by the “strip sample” method. all samples must always be selected by the point method, and extracted from the smallest possible intervals (up to 10 cm in length) as thicker intervals of materials of identical properties are very rare in nature (slip-planes are often formed along fine laminae about 1 mm in thickness, and sometimes even less), while only zones with materials presenting the minimum parameters of shear resistance are relevant and critical for exact geotechnical modelling. this was also revealed by detailed investigations in the very narrow slip-plane zone as undertaken in this case, which is in accordance with the assertions made in the introductory part of the paper. acknowledgements this paper is dedicated to the respectful memory of the professor ervin nonveiller, phd (civ. eng.) whose books have greatly assisted us in our work, and who was always there with his well intentioned and helpful advice. we wish to extend our thanks to the following colleagues from the ina d.d. zagreb, section for field and laboratory testing, for their kindness and assistance: jasna tadej for petrographical analyses and microphotographs, zdenka barbić for sem analyses and interpretations, katica kalac for quality photographs of blown up details, and to all other persons that have provided maximum effort in order to increase quality of test-sample photographs. we also wish to thank professor josip tišljar and professor goran durn from the faculty of mining, geology and petroleum engineering, zagreb, for their kind assistance and useful advices. 8. references bsi (1981): bs 5930:1981: code of practice for site investigations (formerly cp 2001).– british standards institution, london, 147 p. hristov, s. (1974): uticaj sekundarnih argiloidnih zona kore raspadanja na hidrogeološka i inženjerskogeološka svojstva nekih terena jugoslavije [influence of secondary argillic disintegration zones on the hydrogeological and engineering geological properties of some terrains in yugoslavia – in croatian and german].– geol. vjesnik, 27, 283–297. iaeg (1981): rock and soil description and classification for engineering geological mapping. report by the iaeg comission on engineering geological mapping.– bull. iaeg, 24, 235–274. jurak, v., miklin, ž., matković, i. & mihalić, s. (1996): data analysis of landslides in the republic of croatia: present state and perspectives.– proceedings of the viith symp. on landslides, trondheim, june 17–21, 1996 – landslides, 1923–1928, a.a. balkema, rotterdam. mihalinec, z. & stanić, b. (1991): postupak trodimenzionalne analize klizišta [three-dimensional slide analysis procedure – in croatian].– građevinar, 42/9, 441–447, zagreb. mitchell, j.k. (1993): fundamentals of soil behavior.– 2nd ed., john wiley & sons, 437 p. morgenstern, n.r. & tchalenko, j.s. (1967): microstructural observations on shear zones from slips in natural clays.– proc. of the geotechnical conf., oslo, 1, 147–153. mulabdić, m., sesar, s. & matacun, z. (1994): hidrometrijska analiza granulometrijskog sastava tla [hydrometric analysis of cohesive soil – in croatian].– proceedings of the symposium geotechnical engineering in transportation projects, novigrad, croatia, october 5–8, 1994, 1, 153–158, zagreb. nonveiller, e. (1964): klizište u krutoj raspucaloj diluvijalnoj glini na prekrižju u zagrebu [the landslide in stiff fractured clay at prekrižje in zagreb – in croatian].– građevinar, 16/2, 58–64, zagreb. nonveiller, e. (1979): mehanika tla i temeljenje građevina [soil mechanics and foundation of structures – in croatian].– školska knjiga, zagreb, 780 p. 202 geologia croatica 57/2 203jurak et al.: verification of engineering-geological/geotechnical correlation... ortolan, ž. (1990): le rôle de la methode de correlation dans la determination des zones de parametres minimaux de resistance au cisaillement [the role of correlation methods in determining zones of minimum parameters of the shear resistance – in french].– proc. of the sixth int. congress iaeg, august 6–10, 1990, amsterdam, 1675–1679, a.a. balkema, rotterdam. ortolan, ž. (1996): formiranje prostornog inženjerskogeološkog modela dubokog klizišta s više kliznih ploha (na primjeru klizišta podsused) [the creation of a spatial engineering-geological model of deep multi-layered landslide (on an example of the podsused landslide in zagreb) – in croatian with an english abstract].– unpubl. phd thesis, university of zagreb, 245 p. ortolan, ž. (2000): a novel aproach to the modelling of deep complex landslides with several sliding planes. landslides in research, theory and practice.– proc. 8th int. symp. on landslides, issmge & bgs june 26–30 2000, cardiff, 3, 1153–1158, thomas telford, london. ortolan, ž. & mihalinec, z. (1998): plasticity index – indicator of shear strength and a major axis of geotechnical modelling.– proc. of the xith danube–european conference on soil mechanics and geotechnical engineering, may 25–29, 1998, poreč, 743–750, a.a. balkema, rotterdam. ortolan, ž. & pleško, j. (1992): repeated photogrammetric measurements at shaping geotechnical models of multi-layer landslides.– rudarsko-geološko-naftni zbornik, 4, 51–58, zagreb. ortolan, ž., mihalinec, z., stanić, b. & pleško, j. (1995): application of repeated photogrammetric measurements at shaping geotechnical models of multi-layer landslides.– proc. 6th int. symp. on landslides, february 10–14, 1992, christchurch, 1685–1691. a.a. balkema, rotterdam. rac, m.v. (1973): strukturnije modeli v inženernoj geologii [structural models in engineering geology – in russian].– nedra, moskva, 214 p. skempton, a.w. (1985): residual strength of clays in landslides, folded strata and the laboratory.– geotechnique, 35/1, 3–18, london. środoń, j. (1984): x-ray powder diffraction identification of illitic materials.– clays and clay minerals, 32, 337– 349. stanić, b. & nonveiller, e. (1996): the kostanjek landslide in zagreb.– engineering geology, 42, 269–283. manuscript received february 28, 2003. revised manuscript accepted november 08, 2004. 204 geologia croatica 57/2 1. introduction in the aydıncık area an autochtonous sequence of platform carbonate rocks was deposited, ranging in age from the liassic to the aptian. the sequence conformably overlies upper triassic basal conglomerates, interbedded with mudstones and sandstones (demi . r t aşli, 1984), and is unconformably overlain by upper campanian fore-reef carbonate breccia and limestone (tasli & eren, 1999). the biostratigraphy of jurassic-cretaceous carbonate sequences of the central taurides has been studied by the author since 1997. the present work on the aydıncık profile forms part of the ongoing studies, such as tasli (2000). the late jurassic section is particularly rich in benthic foraminifera belonging to the families pfenderinidae (kurnubiinae) and valvulinidae. this benthic foraminifera of the upper jurassic platform carbonate sequence in the aydıncık (i . çel) area, central taurides, s turkey kemal tasli association corresponds to that of coeval facies of the mediterranean realm (henson, 1948b; sartoni & crescenti, 1962; hottinger, 1967; gu©i∆, 1969; nikler & soka», 1968; veli∆, 1977; septfontaine, 1980) and is linked with shallowwater, protected lagoon carbonates. jurassic benthic foraminifera from the taurus mountains were reported from north of isparta (gutnic & moullade, 1967), north and northwest of antalya (bassoullet & poisson, 1975), east of kayseri (altiner & septfontaine, 1979) and munzur dağ (bassoullet & bergougnan, 1981). the aim of this paper is to describe some important species of benthic foraminifera. for the present study, approximately eighty random thin-sections from twenty-five fossiliferous samples within the measured stratigraphic section were studied. micropalaeontological determinations are based on the study of these random thin-sections and a large number of successive acetate peels and polished samples. 2. location and field description of the aydincik profile the aydıncık upper jurassic profile is located about 2 km along the road to karaseki village west of aydıncık (i . çel) town (fig. 1). it continuously overlies an alternation of dolomite and limestone of late dogger age (tasli, 2000) and is about 50 m thick. its upper limit is marked by the reappearance of entirely dolomitic beds representing the transition between the jurassic and the cretaceous, which is easily recognizable in the field because of its morphological difference. the analyzed section consists of light brown, predominantly thick-bedded limestones. c l a d o c o r o p s i s m i r a b i l i s felix, although occuring sporadically in the underlying beds (i.e. in the upper dogger), is so frequent and abundant that it seems to be lithologically dependent. 3. biostratigraphy stratigraphic distribution of the benthic foraminifera and calcareous algae is shown in fig. 2. the analyzed geologia croatica 54/1 1 13 2 figs. 1 tab. 3 pls. zagreb 2001 key words: benthic foraminifera, carbonate platform, upper jurassic, central taurides, turkey. mersin üniversitesi jeoloji mühendisliǧi bölümü, tr-33342 i . ç e l , türkiye. e-mail: ktasli@mersin.edu.tr abstract the upper jurassic sequence of the aydıncık (i . çel) area consists of platform limestones which were deposited in a subtidal, restricted lagoon environment. stratigraphic distribution of benthic foraminifera and calcareous algae, examined in thin-sections, is shown in a rangechart. the microfossil assemblage indicates the salpingoporella sellii subzone of the kurnubia palastiniensis cenozone, corresponding approximately to the lower part of the malm. some benthic foraminifera with considerable stratigraphic value within the mesozoic tethys are described. among the benthic foraminifera, taxa of the family pfenderinidae, especially the subfamily kurnubiinae, are dominant and frequent throughout the sequence. the planispirally coiled taxa are represented by the families nautiloculinidae, charentiidae and cyclamminidae (subfamily bucciccrenatinae). 2 geologia croatica 54/1 limestones continuously overlie limestones and dolomites corresponding the underlying biostratigraphic unit, paleopfenderina salernitana cenozone of sartoni & crescenti (1962) (tasli, 2000). kurnubia palas t i n i e n s i s henson, an index species of the cenozone established by sartoni & crescenti (1962) in the apennines, is frequent and locally abundant throughout the sequence. this species is known to occur through the whole malm of the mediterranean realm (e.g. veli∆, 1977; septfontaine, 1980). the presence of salpingoporella sellii (crescenti) (pl. iii, fig. 10), a dasycladacean alga used as an index species in the apennines (sartoni & crescenti (1962) and dinarides (nikler & soka», 1968; gu©i∆ et al., 1971; veli∆, 1977), indicates the s. sellii s u b z o n e which corresponds approximately to the lower part of the malm. 4. microfacies development and palaeoenvironmental setting the limestones consist mainly of fossiliferous wackestones and biopeloidal grainstones, with oncoids. intraclastic grainstones with f a v r e i n a sp. only occur in the uppermost part of the sequence. the presence of abundant, well preserved cladocoropsis mirabilis f e l i x , centimetre-sized oncoids and benthic foraminifera are characteristic for these limestones. benthic foraminifera are most abundant regarding both the number of species and individuals, whereas calcareous algae are subordinate. dasycladacean algae are represented by salpingo porella annulata carozzi (pl. iii, fig. 11), which is locally common, and rarely by salpingoporella sellii (crescenti). thaumatoporella parvovesiculifera (raineri) (pl. iii, fig. 12) is frequent, but not abunfig. 1 the geographic subdivisions of the taurides (after özgül, 1984) and location of the upper jurassic section. dant. bioclastic fraction is mainly composed of fragments of c l a d o c o r o p s i s , pelecypods and subordinately brachiopods (punctate), ostracods and echinoids. calcareous sponge spicules are locally abundant. siliciclastic material is totally absent. predominantly dense micrites and abundant oncoids indicate low energy in a sheltered environment and shallow-water conditions. intraclastic grainstones with favreina sp. in the uppermost part of the sequence indicate high energy conditions, resulting in the development of a regressive facies. 5. systematic descriptions family nautiloculinidae loeblich & tappan, 1985 genus nautiloculina mohler, 1938; emend. brönnimann, 1967 type-species: nautiloculina oolithica mohler, 1938 nautiloculina circularis (said & barakat), 1959 (pl. i, fig. 1) 1966 nautiloculina circularis (said & barakat).derin & reiss, photo nos. 70, 71, 83, 254, 263, 264, 271, 280, 283, 286-289, 309. 1968 nautiloculina circularis (said & barakat).brönnimann, p. 64, fig. 3, pl. 1, figs. 1-8, pl. 2, figs. 1-6. 1977 nautiloculina oolithica mohler.veli∆, pl. viii, figs. 7, 8. 1985 nautiloculina circularis (said & barakat).fourcade, arafa & sigal, pl. 3, fig. 4. m a t e r i a l : twelve random thin-sections with approximately eighty specimens. description and remarks : this form with lenticular-shaped, involute-planispirally coiled test shows the umbilical fillings and axial depressions. brönnimann (1968) distinguishes n. circularis from n . o o l i t h i c a mohler by the marked subacute periphery, axial depressions, and by the larger size and larger numbers of the whorls in the former. arnaud-vanneau & peybernès (1978) give a comparison table of the principal characters of the four species of n a u t i l o c u l i n a (including the two cretaceous species). in our material there are specimens which are assignable to the species n. circularis and n. oolithica (pl. 1, fig. 2), with the dominance of the former. 3tasli: benthic foraminifera of the upper jurassic platform carbonate sequence... fig. 2 stratigraphic column of the aydıncık upper jurassic section and distribution of benthic foraminifera and other microorganisms. 4 geologia croatica 54/1 d i m e n s i o n s : the measurements are from axial sections only (12 specimens). equatorial and axial diameters vary between 0.55-0.80 mm, and 0.30-0.48 mm, respectively. the ratio of equatorial/axial diameter oscillates around 1.8:1. the inner diameter of proloculus ranges from 0.03 mm to 0.05 mm. family charentiidae loeblich & tappan, 1985 genus karaisella kurbatov, 1971 type-species: karaisella uzbekistanica kurbatov, 1971 karaisella aff. uzbekistanica kurbatov, 1971 (pl. i, figs. 3-13) ?1958 h a p l o p h r a g m i u m aff. s u p r a j u r a s s i c u m s c hwager.dufaure, pl. 1, figs. 21-22. ?1968 haplophragmium cf. suprajurassicum schwager.nikler & soka», pl. ix, fig. 7. material : fifteen random thin-sections and ten succesive acetate peels with approximately ninety specimens. d e s c r i p t i o n : test is free, lenticular shaped, thickened towards the poles, with small axial depressions. peripheral margin is rounded to subrounded. septal sutures, observed in equatorial sections (pl. i, figs. 6, 7), are slightly depressed. coiling is planispiral, occasionally streptospiral, and involute, with a tendency to become uncoiled in the later stage (pl. i, fig. 12). there are two or at maximum three and a half whorls. the number of chambers in the last whorl is nine to twelve. chamber interiors are simple. septa are curved and inclined in the direction of coiling, in continuity with the outer wall. the base of the septum against the previous whorl is thickened and chomata-like (pl. i, figs. 810). septal spacing (= height of chamber) and height of the whorls slightly increase during the ontogeny. megalosphere is simple, spherical or slightly ovoid. aperture is simple and central (pl. i, figs. 6, 7). wall is calcareous microgranular (= finely agglutinated) with a keriothecal structure, occasionally visible only in the last whorl of large specimens (pl. 1, fig. 11). d i m e n s i o n s : dimensions (in mm) are shown in table 1. r e m a r k s : because of its streptospiral coiling, single areal aperture, and the presence of chomata-like thickening at the base of the septa (pl. i, fig. 5), this form is herein assigned to the genus k a r a i s e l l a k u rbatov, 1971 (in loeblich & tappan, 1988). k a r a i s e l l a aff. u z b e k i s t a n i c a is a close homeomorph of the cretaceous genus c h a r e n t i a neumann, 1965, except its streptospiral coiling. the genus k a r a i s e l l a was placed in the family charentidae by loeblich & tappan (1988) although they note that it did not show a canaliculate wall structure (keriothecal structure of hottinger, 1967). specimens in the aydıncık material do not show a sharp change in the plane of coiling from early to later whorls and subacute periphery as in the type species. this form is similar to the genera b u l b o b a c u l i t e s maync, 1952 and h a p l o p h r a g m i u m reuss, 1860 in areal aperture and the streptospiral nature of coiling. however, the wall is distinctly agglutinated and simple in the former genus, and alveolar in the latter. moresample greater inner diameter no. (ay) specimens equatorial axial diameter of proloculus diameter 38-1 1 (pl.1, fig. 4) 0.85 0.45 0.05-0.06 38-1 2 0.63 0.30 not observed 38-1 3 0.55 0.04 38-3 4 0.70 0.06 38-3 5 0.65 not observed 38-3 6 (pl.1, fig. 10) 0.80 not observed 38-3 7 0.85 0.12 38-4 8 0.72 not observed 38-5 9 0.70 0.05 38-6 10 (pl.1, fig. 6) 0.48 0.30 0.06 38-6 11 (pl.1, fig. 11) 0.90 not observed 38-6 12 (pl.1, fig. 9) 0.65 0.06 38-6 13 0.66 0.11 38-8 14 (pl.1, fig.6) 0.70 0.10 38-8 15 0.75 0.40 0.05 38-10 16 0.47 0.06 38-10 17 0.70 0.13-0.15 38-13 18 (pl. i, fig.7) 0.46 0.06 38-14 19 0.50 0.07 table 1 dimensions of karaisella a f f . uzbekistanica (in mm). 5tasli: benthic foraminifera of the upper jurassic platform carbonate sequence... over, both genera have a marked rectilinear uniserial stage which is only occasionally developed in our specimens. karaisella aff. uzbekistanica differs from another upper jurassic species, mesoendothyra izjumiana dain, 1958 (with its wall consisting of large pores, dain in bykova et al., 1958), by the central position of the aperture, the presence of chomata-like thickenings in the base of the septum and by a lacking of distinct streptospiral coiling. k a r a i s e l l a aff. uzbekistanica closely resembles the genus b o s n i e l l a gu©i∆, 1977 by its keriothecal wall structure and growth pattern, but differs from it in the absence of a peneropline stage with cribrate aperture and in having only a central aperture. in the latter, the aperture is at first basal, then central and finally cribrate as in “mesoendothyra” croatica gu©i∆ (gu©i∆, 1969; furrer & septfontaine, 1977). the genus b o s n i e l l a is represented by two species: b. oenensis f r o m the lower jurassic of nw bosnia (gu©i∆, 1977) and b. fontainei from the middle jurassic of thaïland (bassoullet, 1994). it is considered as a junior synonym of m e s o e n d o t h y r a dain (septfontaine, 1988). alternatively, bassoullet (1994) removed “m e s o e n d o t h y r a” c r o a t i c a gu©i∆ from the genus m e s o e n d o t h y r a dain, because of its keriothecal wall structure, and assigned it to the genus b o s n i e l l a g u©i∆, 1977. o c c u r e n c e : it is abundant in biopeloidal grainstones with oncoids, in association with nautiloculina cir c u l a r i s and kurnubia ex. gr. p a l a s t i n i e n s i s , whereas it is missing or rare in fossiliferous wackestones. family pfenderinidae smout & sugden, 1962 subfamily kurnubiinae redmond, 1964 genus kurnubia henson, 1948 type species: kurnubia palastiniensis henson, 1948 after smout & sugden (1962), who assigned henson’s (1948b) species valvulinella jurassica a n d v. wellingsi to the genus k u r n u b i a henson and after sartoni & crescenti (1962), who considered the species k. jurassica synonymous with kurnubia palas t i n i e n s i s, redmond (1964) described, from isolated specimens only, three new species of k u r n u b i a : k . v a r i a b i l i s , k. bramkampi and k. m o r r i s i . maync (1965) included all these species in kurnubia gr. palas t i n i e n s i s henson, except k. morrisi, considering the existence of intermediate forms. gu©i∆ (1969) adopted maync’s (1965) opinion and considered the three infrasubspecific taxa as “forms” j u r a s s i c a , p a l a s t i n i e n s i s and w e l l i n g s i. hottinger (1967) redescribed k . p a l a s t i n i e n s i s in detail, including k. jurassica , and retained the three redmond’s (1964) species of kur nubia. later, this common late jurassic genus has been recorded mostly under the name kurnubia palastinien s i s henson in many studies (e.g. bassoullet & poisson, 1975; azéma et al., 1977; veli∆, 1977; fourcade et al., 1985; luperto-sinni & masse, 1994). in general, redmond’s (1964) species seem not to be accepted, probably owing to difficulties in comparing with isolated specimens. the aim of the following descriptions is to contribute more data to the existing knowledge on the subfamily kurnubiinae, avoiding the creation of new taxa. kurnubia ex. gr. palastiniensis henson, 1948b (pl. ii, figs. 1-7) d e s c r i p t i o n : see description in hottinger (1967). r e m a r k s : our specimens display wide morphologic variations and considerable differences in size. they vary from those smaller in size, only trochospirally, having a weakly developed central column and possessing a hypodermic network (septfontaine, 1988) with first order partitions (pl. ii, figs. 1, 2, 5), to those having a larger test with a marked central column, a more or less developed uniserial stage, and possessing a complete hypodermic network (pl. ii, figs. 4, 6). the former have a simple, ovoid proloculus, measuring about 0.04 mm (inner diameter) and representing the megalospheric generation. they are included in this group due to the presence of the transitional forms. in the latter forms, the proloculus is not visible. the central column seems to be weakly developed in highly conical specimens (pl. ii, fig. 6), whereas it is well developed in specimens having a relatively larger basal diameter (pl. ii, figs. 3, 4). kurnubia cf. morrisi redmond, 1964 (pl. ii, figs. 8-12, 14) ?1964 kurnubia morrisi new species.redmond, p. 253, pl. 1, fig. 4. 1967 kurnubia cf. m o r r i s i redmond.hottinger, p. 93, pl. 19, figs. 35-37. d e s c r i p t i o n : test is fusiform, trochospirally coiled throughout the ontogeny. early chambers are not visible. spiral sutures are depressed, at about 30°to the axis of coiling. septal sutures are obscure. the wall is calcareous, microgranular without agglutinated grains, possessing a complete hypodermic network. the primary aperture is set in the inner margin of the peripheral zone where the septa do not meet the central column (pl. 2, fig. 11). it probably represents “intercameral foramina” (smout & sugden, 1962). prolongations of the adjacent first order vertical partitions projecting inward from the epidermis adjoin to each other and coalesce with the interseptal pillars (pl. ii, fig. 10). the second order vertical partitions are restricted only to the marginal zone of the chambers. the central zone has a trochoidally laminated appearance (pl. 2, fig. 14) 6 geologia croatica 54/1 which recalls the apertural plates intergrown with pillars in the pfenderinidae. the base of the test is strongly convex in the centre and very obliquely set to the axis of coiling. d i m e n s i o n s : axial length varies from 2.1-2.5 mm, measured in nearly axial sections. basal diameter is ≥ 0.8 mm and exceeds up to 1.0 mm. the ratio of length/diameter oscillates around 2.5:1. the width of the peripheral zone surrounding the central zone is nearly constant throughout the adult stage, measuring 0.20-0.22 mm. the central column increases progressively in diameter, up to 0.5 mm. remarks : k. cf. morrisi has a larger test and central column, and a wider peripheral zone than all other described species of kurnubia and a complete hypodermic network consisting of two generations of partitions in the adult stage. furthermore, specimens of kurnubia ex. gr. p a l a s t i n i e n s i s do not exceed 0.7 mm in basal diameter. purely because of the trochospiral coiling, this form is not considered as k. w e l l i n g s i ( h e n s o n ) . six to eight tiers of chamberlets per chamber, mentioned by redmond (1964, p. 253), are not accountable in random thin sections. genus conicokurnubia septfontaine, 1988 type species conicokurnubia orbitoliniformis septfontaine, 1988 conicokurnubia orbitoliniformis septfontaine, 1988 (pl. ii, figs. 13, 15, 16) description : test is sharply conical (pl. ii, fig. 13), where chambers do not increase in diameter as added, and broadly conical where chambers increase slowly in diameter. the base is slightly to strongly convex in the centre, with a narrow imperforate rim. the cone side is straight. proloculus is not visible. the trochospiral arrangement of the early chambers is suggested by traces of the spiral suture. later and remaining larger portion of the test consists of a co-axial series of ten to seventeen very low chambers which increase slightly in height as added. septal sutures are distinct and depressed. each chamber has a peripheral zone with a complete hypodermic network. each septum is inwardly thickened and then adjoins with the adjacent septum, forming buttress-like interseptal pillars (pl. ii, fig. 15). the first order vertical partitions form a “reticulate zone” (henson, 1948a) in the centre of the test as seen in transverse sections (pl. ii, fig. 16). apertural pores are not observable. the primary aperture consists of an opening near the margin of the central zone (pl. ii, fig. 15). d i m e n s i o n s : the broadly conical specimens have a basal diameter of 1.25-1.50 mm and a height of 1.751.85 mm, measured in nearly axial sections. the sharply conical specimens have a basal diameter of 0.50-0.70 mm and a height of 1.25-2.0 mm, measured in nearly axial sections. the height of the last chamber, for both forms, is ≤ 0.1 mm. the width of the peripheral zone surrounding the central column is 0.10-0.12 mm. remarks : specimens of this species from aydıncık are closely comparable with septfontaine’s (1988) figures (pl. ii, figs. 12, 13) from the oxfordian (?) to kimmeridgian of western taurus, turkey. however, the available axial and transverse sections are insufficient for a complete description of the species. conicokurnubia orbitoliniformis occurs throughout the aydıncık upper jurassic section, in association with k u r n u b i a ex gr. p a l a s t i n i e n s i s . in the random thin-sections, specimens with a marked uniserial stage of the latter might be confused with sharply conical specimens of c. orbitoliniformis. the width of the peripheral zone seems to be narrower than in kurnubia palastiniensis and kurnubia aff. morrisi. 6. biostratigraphic review and conclusions the characteristics of the upper jurassic limestone section from the aydıncık (i . çel) area are the presence of c l a d o c o r o p s i s , benthic foraminifera, calcareous algae and the dominance of mudstones which indicate a subtidal, protected lagoon environment. stratigraphic distribution of the benthic foraminifera and calcareous algae is shown in a range-chart. microfossil assemblage corresponds to the s a l p i n g o p o r e l l a s e l l i i subzone of kurnubia palastiniensis c e n o z o n e , established by sartoni & crescenti (1962). ten species of benthic foraminifera are identified and figured. those of considerable stratigraphic value within the mesozoic tethys are described. 7. references altiner, d. & septfontaine, m. (1979): micropaléontologie, stratigraphie et environnement de déposition d’une série jurassique a facies de plate-forme de la région de pınarbaşı (taurus oriental, turquie).rev. micropaléont., 22/1, 3-18. arnaud-vanneau, a. & peybernès, b. (1978): les représentants éocrétacés du genre n a u t i l o c u l i n a m o hler, 1938 (foraminifera, fam. lituolidae?) dans les chaines subalpines septentrionales (vercors) et les pyrénées franco-espagnoles. revision de nautiloculina cretacea peybernès, 1976 et description de nautiloculina bron nimanni n. sp.geobios, 11/1, 67-81. azéma j., chabrier, g., fourcade, e. & jaffrezo, m. (1977): nouvelles données micropaléontologiques, stratigraphiques et paléogéographiques sur le portlandien et le néocomien de sardaigne.rev. micropaléont., 20/3, 125-139. 7tasli: benthic foraminifera of the upper jurassic platform carbonate sequence... bassoullet, j.-p. & poisson, a. (1975): microfacies du jurassique de la région d’antalya (secteurs n et nw), taurus lycien (turquie).rev. micropaléont., 18/1, 3-14. bassoullet, j.-p. (1994): bosniella fontainei nov. sp. (foraminifère, biokovinidae) du jurassique moyen de thaïlande.geobios, 27/4, 403-411. bassoullet, j.-p. & bergougnan, h. (1981): faune et facies typiques du domaine sud-tethysien: le lias du munzur dağ (anatolie orientale).bull. soc. géol. france, 7/xxiii-1, 83-93. brönnimann, p. (1968): re-examination of the morphology of nautiloculina circularis (said & barakat), 1959, from the upper jurassic of egypt and israel.c.r. séances, sphn 2/1, 62-73. bykova, n.k., balakhmatova, y.t., vassilenko, v.p., voloshinova, n.a., grigelis, a., dain, l.g., nanova, l.v., kuzina, v.i., kuznetsova, z.v., kozyreva, v.f., morozova, v.g., myatlyuk, e.v. & subbotina, n.n. (1958): new genera and species of foraminifers.vsenoyuznyi nefteni nauchnoissledovatelskii geologii zazved institut, trudy, 115, microfaune d’urss, 9, 4-81 (in russian). d e mi . r t aşli, e. (1984): stratigraphy and tectonics of the area between silifke and anamur, central taurus mountains.in: tekeli . , o. & göncüoğlu, m.c. (eds.): int. symposium on the geology of the taurus belt, 1983, proceedings, mta spec. pub., 101-118. derin, b. & reiss, z. (1966): jurassic microfacies of israel.spec. publ. inst. petr., 1-43. dufaure, ph. (1958): contribution à l’étude stratigraphique et micropaléontologique du jurassique et du néocomien de l’aquitaine à la provence.rev. micropaléont., 1/2, 87-115. fourcade, e., arafa, a.a. & sigal, j. (1985): description d’une nouvelle espèce de foraminifère du malm du proche-orient: m a n g a s h t i a ? e g y p t i e n s i s n.sp.rev. micropaléont., 27, 21-29. furrer, v. & septfontaine, m. (1977): nouvelles données biostratigraphiques (à l’aide des foraminiferès) dans le dogger à faciès briançonnais des préalpes médianes romandes (suisse).-eclogae geol. helv., 70/3, 717737. gu©i∆, i. (1969): some new and inadequately known jurassic foraminifers from central croatia.geol. vjesn., 22, 55-88. gu©i∆, i. (1977): a new foraminiferal family, biokovinidae, from the jurassic of the dinarids and its phyllogenetic relationships.palaeontologia jugoslavica, 18, 3-31, zagreb. gu©i∆, i., nikler, l. & soka», b. (1971): the jurassic in the dinaric mountains of croatia and the problems of its subdivision.ann. inst. geol. pub. hungarici, liv (2), 165-183. gutnic, m. & moullade, m. (1967): new data on the jurassic-lower cretaceous of barla mountain in south of senirkent.mta bull., 69, 58-78. henson, f.r.s. (1948a): larger imperforate foraminifera of south western asia.brit. mus. nat. hist., 1-127. henson, f.r.s. (1948b): new trochamminidae and verneuilinidae from the middle east.ann. & mag. nat. hist., (11) 14, 605-630. hottinger, l. (1967): foraminifères imperforés du mésozoique marocain.notes mem. serv. geol. maroc, 209, 1168. loeblich, a.r.jr. & tappan, h. (1988): foraminiferal genera and their classification.van nostrand reinhold co., new york, 1127 p. luperto-sinni, e. & masse, j.p. (1994): precisazioni micropaleontologiche sulle formazioni di piattaforma carbonatica del giurassica superiore e del cretaceo basale del massiccio del gargano (italia meridionale) e implicazioni stratigrafiche.palaeopelagos, 4, 243-266. maync, w. (1965): some comments on d.c. redmond’s new lituolid foraminifera from saudi arabia.rev. micropaléont., 8/1, 37-40. nikler, l. & soka», b. (1968): biostratigraphy of the jurassic of velebit (croatia).geol. vjesn., 21, 161-176. özgül, n. (1984): stratigraphic and tectonic evolution of the central taurides.in: tekeli . , o. & göncüoğlu, m. c. (eds.): int. symposium on the geology of the taurus belt, 1983, proceedings, mta spec. pub., 77-90. redmond, c.d. (1964): the foraminiferal family pfenderinidae in the jurassic of saudi arabia.micropaleontology, 10/2, 251-263. sartoni, s. & crescenti, u. (1962): ricerche biostratigrafiche nel mesozoico dell’appennino meridionale.giorn. geol. (ann. museo geol. bologna), 2/29, 162-302. septfontaine, m. (1980): les foraminifères imperforés des milieux de plate-forme au mésozoique: détermination pratique, interprétation phylogénétique et utilisation biostratigraphique.rev. micropaléont., 23/3-4, 169-203. septfontaine, m. (1988): vers une classification évolutive des lituolidés (foraminifères) jurassiques en milieu de plate-forme carbonatée.rev. paléobiol., vol. spec. 2, benthos ‘86, 229-256. smout, a.h. & sugden, w. (1962): new information on the foraminiferal genus p f e n d e r i n a .paleontology, 4/4, 581-591. tasli, k. (2000): kilianina blanchetiformis n. sp. and benthic foraminifers of the dogger carbonate sequence in the a y d ı n c ı k (i . çel) area, central taurides, s turkey.revue de paleobiol., 19/1, 165-177. tasli, k. & eren, m. (1999): stratigraphic and sedimentologic aproach to the aptian-campanian erosional unconformity in the aydıncık (i . çel) area, central taurides, s turkey.geosound, 34, 1-17. veli∆, i. (1977): jurassic and lower cretaceous assemblage zones in mt. velika kapela, central croatia.acta geol., 9/2, 16-32, zagreb. manuscript received august 24, 2000. revised manuscript accepted april 23, 2001. 8 geologia croatica 54/1 plate i scale bar: 0.2 mm fig. 1 nautiloculina circularis (said & barakat) axial section showing the acute periphery through the ontogeny, sample ay 38-9. fig. 2 nautiloculina oolithica mohler axial section showing the rounded periphery, sample ay 38-9. figs. 3-13 karaisella aff. uzbekistanica kurbatov 3: axial section showing streptospiral coiling in the two early whorls, sample ay 38-8; 4: oblique axial section showing spherical proloculus, sample ay 38-1; 5: subaxial section, sample ay 38-4; 6: axial (megalospheric specimen) and oblique subequatorial sections, sample ay38-6; 7: equatorial section of a megalospheric specimen, sample ay 38-13; 8: equatorial section showing the chomata-like thickenings in the base of the septa, as the genus c h a r e n t i a neumann, sample ay 38-8; 9: equatorial section offset by a fracture, showing thinning of the septa towards the apertural area, sample ay 38-6; 10: oblique subequatorial section, sample ay 38-3; 11: oblique equatorial section of a probable microspheric specimen revealing the keriothecal wall structure in the last whorl (arrow), sample ay 38-6; 12: oblique section of a probable microspheric specimen revealing terminally uncoiled chambers, sample ay 38-14; 13: subaxial section, sample ay 38-5. 9tasli plate i 10 geologia croatica 54/1 plate ii scale bar: 0.2 mm figs. 1-7 kurnubia ex. gr. palastiniensis henson 1: axial section of a megalospheric specimen revealing an ovoid proloculus, sample ay 50; 2: axial section showing the first order horizontal partitions only and a weakly developed central column, sample l 4-3; 3: subaxial section, sample ay 38-12; 4: subaxial section, sample ay 50; 5: oblique axial section, sample l 4-1; 6: nearly axial section of a highly conical specimen, sample ay 40; 7: oblique transverse section, sample l 3-2. figs. 8-12, 14 kurnubia cf. morrisi redmond 8: oblique axial section, sample l 4-2; 9: oblique transverse-tangential section, sample l 1; 10: transverse section showing the first and second order vertical partitions in the peripheral zone, sample l 7; 11: oblique axial section showing the second order partitions which are missing in the deeper part of the peripheral zone. note that the septa do not meet the central column, leaving an opening near the margin of the central column, sample ay 50; 12: oblique transverse section resembling fig. 7, included in this species because of its larger diameter, sample ay 49; 14: subaxial section showing curved thin plates in the central column, sample ay 42. figs. 13, 15, 16 conicokurnubia orbitoliniformis septfontaine 13: subaxial section of a highly conical specimen revealing strongly convex base in the centre, sample ay 45; 15: subaxial section showing labyrinthian appearance of the central zone occupied by interseptal pillars. note the early portion of the cone recalling trochospiral coiling during the early ontogeny, sample l 3; 16: transverse section passed through the adult stage of a large conical specimen, sample ay 41. 11tasli plate ii 12 geologia croatica 54/1 plate iii scale bar: 0.2 mm fig. 1 everticyclammina sp. subaxial section showing a broadly rounded periphery which is not known in the other jurassic species, e. virguliana (koechlin), sample ay 47. fig. 2 indet. lituolidae equatorial-longitudinal section, sample l 4-3. fig. 3 valvulina lugeoni septfontaine subaxial section, sample l 7. figs. 4, 5 pfenderina sp. 4: axial section of a broken specimen revealing the keriothecal wall structure, sample l 4-3; 5: transverse section, sample ay 45. figs. 6, 7 verneuilina sp. 6: subaxial section, sample ay 38-9; 7: transverse section, sample ay 50. fig. 8 siphovalvulina sp. axial section showing the spheric proloculus and siphonal canal, sample ay 43. fig. 9 aeolisaccus sp. sample ay 47. fig. 10 salpingoporella sellii (crescenti) sample l 4-2. fig. 11 salpingoporella annulata carozzi sample ay 38-14. fig. 12 thaumatoporella parvovesiculifera (raineri) sample ay 38-9. 13tasli plate iii 14 geologia croatica 54/1 geol. c roat. 49/2 259 ·263 3 figs. i 1 tab. zagreb 1996 scienr{ji't.: i/ofe how a better knowledge of the basins can reduce the risk of exploration: input of basin modelling a lan mascle' and bernard durand' proceedings key words: weste rn alps, basin mode llin g, ri sk of ex ploration. abstract basin modelling so fhvarc has been wid ely developed in (lie bo's ,'11(\ is still the subject of active research and development in the oil compan ies, con tractors ilnd consultant agencies, and al so in the uni ­ versi ti es . a complete range of so ft ware applic<lblc to the basin level arc now available [0 cxpl oralioni sls, includi ng 1-0, 2-d and soon 3-d tools. mosl of them arc devoted to the va lidation o f glruclura] hypotheses, to the prediction of source rock maturil ics. or [0 a recon­ struc tion of petroleum formation and m igrati on in bas ins. another class of so ftware, mostly developed in the un ivers ities, attempts to describe the th ermomechanical behaviour of th e lithosphere du ri ng bas in formation and subsequent inversion (durand cl nl., 1997). the question now i s: how can these tool s help explorationists in reducing the risks (and as a consequence the cos!.~) of exploration? in order to discuss and answer this question, we wil l present a case study in which ifop sort ware has been used to reassess the petro­ leum potential of the southeast basin and gul f of lyon in se france. these two area.~ have been the locus of aelive ex ploration from the 60's to the ea rl y 80's, withou t commerc ial result s. the analys is and appraisal of failures have already been done and tile different poten­ tial petro leum systems recognized. then l -d and 2-d modell ing was performed in order to selcct within thi s 50,000 km 2 area the few pl<lces where further exploration can be conducted wilh a minimum of technical and economic haz:trd s. 1. reg ional setting the southeast bas in is thc thickes t onshore french sedimentary bas in w he re li p to 10 kill of mesozoic­ cenozoic sediments can be found loca lly ( fig . i ). basin dcve lopme nt occ urred in scvc ral stages be twee n lale ca rbonirerous and lal e crctaccous timcs. partia l tccton­ ic invcrsion look place during i wo compressive even is, in early and late tertiary times. they were separated by an intervening stretc hing evcnt of oli gocenc agc, whi ch led i'u nher south , to the o pening up of the wes te rn medite rranean margins and ocean in burd igal ian times (i ncluding the gulf of lyon located immediate ly sout h i inslitul rran~ai s ell! pclrole, bp 311, 92506-ruci l malmaisol1, france. 2 ecolc naliol1:llc supcricurc du pctrotc el dcs motcurs, bp 311, 92506-rueil malmaison. f"ince. of the southeas t basin). in neogene timcs the pal aeo­ zo ic baseme nt of the mass if central was uplifted to about 2000 iii as the result of an ascending as lhe nos­ pheric plume. 2. methodology a large o il seep has been e xplo ited s ince a t least 1608 in the vic inity of what wi ll la ter become the tiny gabian o il field. most of the explorat ion unde rtaken from 1955 (onshore) and 1975 (offshore) to the present has been d isappointing as no significant oil or gas fi e ld has cvcr been discove red, although about 150 wells have bee n d ri lled. a reasscssmc nt of the rc maining potential o f the southeast bas in and gulf of lyon bas in has been undertaken by lfp s ince 1991. t he main o bjecti ve was to se lect the few arcas where pot e ntial plays have not yct been tes ted, and where furt he r ex plo­ ra tion co uld be undc rtaken w ith a minimulll o f ri sks . the agenda of works has been as followed: a) synthes is of all avai lable geological data; b) e labora tion of the geochemical and geophys ica l clata base; c) ana lysis of failures in prev ious ex plo ration we lls; d) appra isal of the different pe troleum syste ms; e) j-d and 2-d nume rical modelling of selected s itcs or transects . jtcms a-d are class ic works for a ny basin evaluat ion. howcver, their importance should not be undercstima­ ted as the quality and thc con fid e ncc in the rnode ll ing wi ll direc tly be linked 10 the quality of the input data . the selec tion of the mode lli ng lools will also be depen­ dent on the availability of quality data. 1-d modelling is easy to operate and the result s are very rapidly obtained. numerous hypotheses can thus be tes ted for a low cos t, and these tools wi ll be used when only a limited amount of data is ava il ab le. conve rsc ly, 2-d mode llin g tool s are more diffic ult to operate and are time consu ming (for bo th people and computers). only a few geolog ical hypotheses can be tes ted, a nd the use of suc h 100ls should be restric ted to are as whe re a complc te se t of good quality data can be obtained . 260 south·east basin o km po plain '00 3. a v ailable basin modelling software software developed at i[<p cover a wiele range of geological processes. \-d software sllch as "genex" will be lised to model the subsidence, thermal and source rock maturity histories of selected sites in sedi­ mentary basins (sec one application in the gulf of lyon; fig. 2). such processes within basins can also be investigated with 2-d software such as "thcmispack" or "thcmiscomp", with the benefit that fluid pressures and nows can also be investigated. \vc arc now develo­ ping a s imilar tool , "thruslpack", devoted 10 the study of thrust belts anclthcir foreland; an application on the chartreuse massif or the western alps, once part of the southeast basin, before tectonic inversion in tertiary limes (z iegler & tiorvath. 1997). is shown on fig. 3. or equal importance, the variety of data needed for proper usc of the software is listed in table i. 8 ___ geologia cronlic,! 49/2 fig. i slrucluralmap of the southcast13asin, wcstern alps. lcgend: 1) palaeozoic basemcnt: 2) internal alps; 3) externa l alps and jura thrust belt: 4) western alps foreland: southcast hdsin, pro­ vence plalform; 5) stable europcan craton; 6) tcrtiary basins: po plain. molassc and valence basin, bressc unci rhinc graben: 7) main alpine thrust fronts; 8) main early mcsozoic normal fclllits. 4. concluding remarks i-d and 2-d modelling have been performed across a continental margin (the gulf or lyon) and the foothills of a thrust belt (the western alps), i.c. in areas where exploration is expensive. the benefit or such modclling work is three fold: a) to unite thc work or a multidisciplinary team and to make an atlcmpt to quantify geological data; b)as some important input data arc often not available (the thermal history for instance) it is possible to test several geological hypotheses (either st ructural , geo­ chem ical, thermal, ... ) and to appreciate the range of uncertainties resulting from this lack or data; c) to promote the most appropriate studies to gather the geological data that appear to be of crucial impor­ tance for the petroleum evaluation of the object area. acknowledgements some of thi s work was supported by the ibs project (integrated basin studies), part of the joule research programme funded by the commission of the european communilies (conlract n' jou2-ct-92-01 10). masek & durand: ilow a ue1ter knowledge of the uasins c ui reduce the risk of explor:l lioll .. ): ~ 0 0 z ~ ~ < t.:: r;: i ~ 3 "' < " § .. ~ z · . "' h+--i-+ .. '. ~ , z ~:.;a : ~ ~ "' < " '" z < "' i3 z d ~ 1 0 '" z ~ c i d "' ~ ~ ~ z 0 . < z • " 0 0 ~ ~ ~ ~ z s 0 w < z ~ • 0 31 ~ z "'i ~ ~ , k' ~: , bi. . '" z < l; 1\\ 0 ~ z < '" 0 ;.. ~ ~ 0: f'" q -' < ~ < "-on ,. ~ 0 q z ;;: ~ '" < " q z < -' 0 . = , " , ~ " < = '''; :: 10 . . " " " " "" " " "~ i~ . ---_. -----.;:. :::::: 7::; ;;;; , • .: < ;> " '" to: ~ !!; . ! i .. <: ~ :=:: f.. " x i:i: i ~r .....,"," "-" ", "-" "t"" "" ", " -" "r" ", " -" "-'t~=~t-+' ~ i ~ x ::;. ~ := ' . ' i ~ ~ ~ '£. :7. 1 ~ i ;.. ~ i ~ ~ i ~ = i 261 ri g. 2 gu lf of lyon con tinental marg in (western mediterranean); "genex" modelling o f the maturity history of poten tial source rocks (from vially & tremoli eres. in: z iegler & horvat h. 1997). 1-0 genex modell ing has been performed in ihe oligocenemiocene graben located between the rascassc and tramontane well s. the result s have then been graphically extended (0 the 2-d section. "" cpo w n ~ ~ " ~ 3: ~ " ~ ~ " ~ i ·]o \!u ;i ~ os • ~ 3 ~ = 3' '" s, " " o g 0' • 5. " o " " s~~\ \ · in ifa a 1\ \ ;\ ~ ,'r(,\/' 11/ 3 o 2 3' j .. t ~ " " 0, ~ ", ~""~tq kinematic modeling 1\/ " " chartreuse , ~ • !.\"lj..h type i' llas-oogger source ~ h \'h 2' j<.",1<> ~ i'h ~ 1),_.",,,, -----., . ' ii .. m · 5 .. 1\."" i" , i \\"'<",'" ·on ;c ., i ie " maturity modeling .. basal heat how = 70 mw/m? t ese -'---" " " t t • f n msj ormatiol/ rrllio _ u.09 1i ,1 1i _ 1 •. lh _ u ~,< c:j iu,~ · ii. ~_~ _ . o,~~ _ i ' , "~' _ n_7f1 . , ,111 " 60 ~ r; o g ~ co ~ g' ~ is ivlasck: & du r;llld: ! iowa beller knowledge of the 13a~ in s can rcducc the risk of exploration .. . 263 1. geologic data a. stratigraphic data: well constrained litholog ies and well dated formations (especially syntectonic deposits). b. structural data: well balanced cross-section with the restoration before deformation. c. kinematics data: timing of deformation and displacement rates on faults. d. vertical displacements: erosion and subsidence history. 2. thermal data a. heat flow history (may be estimated from geochemical data) . b. density, thermal conductivity, heat capacity, radiogenic heat and specific area of sediments (avai lable stan­ dard default values vs. lithologies). 3. geochemfcal data a. local cal ibrat ion of source rocks maturity. b. kinetic parameters of sou rce rocks (available standard default values for 4 types of source rocks). t,lblc i rcq llired data for 'thrllstpack" modelling. 5. references du ran d, b. cl a l. (eds.) (1 997) : extension· in·colli ­ sian basins.geological society special publicat ion, in preparation. z ieg ler, p.a. & horvath, f. (eds.) (1997): struc­ lure and prospeels of the alpine basins and forc­ land.peri-tethys memoir, 2, in press. 264 geologia croatica 49/2 1. introduction soil is a vulnerable geological medium, which sustains the bulk of human activities including, among others, the food production as one of the most important. in the age of increasing pollution and devastation of human environment the soil protection deserves every respect and mindfulness, particularly because of its vital importance not only to the human beings but also for the sustenance of each facet of life on this planet as a whole. in order to trace the increasing human contribution to geochemical baseline mapping of soils developed on diverse bedrock from two regions in croatia slobodan miko, josip halami∆ , zoran peh and lidija galovi∆ overall contamination of the planet, particularly by the chemical elements harmful to health, it is necessary to determine the natural content of major and trace elements in soils on the regional scale. up to the present time there was no methodical research in our country as regards finding a solution to this burning worldwide problem. in due time, this work was animated and supported by the ministry of science under the project of geochemical map of the republic of croatia with the scope to detect a pollution problem on a regional scale and pinpoint some target areas in the country where adversities for its inhabitants threaten to become most pronounced. geochemical research has shown a much greater natural variability among almost all elements in soil, irrespective of the soil type, when contrasted to the stream sediment (reimann, 1988). this is a fact that allows reduction of sampling density, fitting it more appropriately into the regional scope of investigation which can be implemented successfully either on carbonate or non-carbonate geological bedrocks. sampling design and analysis have been performed to be complement with recommendations issued by igcp (darnley et al., 1995) and foregs (salminen et al., 1998), which classify soil into the first group of sample materials (regolith) with the widest geochemical applic ability. this paper is aimed to establish the geochemical baselines for a set of chemical elements in the two geographically separate parts of the country whose soils originated on different geological substrates: 1) on predominantly non-carbonate (non-karstic) terrains (northwestern croatia); and 2) predominantly carbonate (karstic) terrains (southern dalmatia). geochemical baselines, or natural background concentrations for a particular element refer to the natural variability of its contents in the secondary (surficial) environment (soils, stream, overbank, floodplain or lake sediments). the geochemical baseline, which has been defined within the igcp 360 project global geochemical baselines, is of essential importance in environmental legislation, which prescribes limits for heavy metals in contaminated land and other surficial materials such as defined by environmental authorities. this is additionally complicated by regional geochemical data showing that natural background concentrations vary widely due to the geologia croatica 54/1 53 118 14 figs. 5 tabs. 45 pls. zagreb 2001 key words: geochemical baseline mapping, soils, environmental geochemistry, heavy metals, pollution, karst, carbonate and non-carbonate bedrock, factor analysis, croatia. institute of geology, sachsova 2, p.o.box 268, hr-10000 zagreb, croatia. e-mail: igi-zagreb@zg.hinet.hr abstract the comparison of contents and distribution maps for al, as, ba, ca, co, cr, cu, fe, la, k, na, ni, mg, mn, p, pb, sc, sr, ti, th, v, y, zn and hg in the topsoil cover of two typical regions are given. one is a carbonate bedrock (karst) dominated region (southern dalmatia) and the other a non-carbonate bedrock dominated region (nw croatia). the results imply that the soils developed on carbonate bedrock have higher mean values of almost all elements excluding k, na, mg and ba, which are lower in carbonate terrains. in comparison with the non-carbonate terrains, for the carbonate terrains the following elements have higher mean concentrations: al, as, co, cu, fe, la, mn, pb, ni, mn, th, v, cr, zn, zr and nb, while sr, p and ti have similar contents. approximately 4% of the sites can be considered as moderately enriched (polluted) in pb, either from mining activities or airborne deposition. only a limited number of sampling sites can be directly linked with mineralization. the derived factors are usually interpreted as associations of elements that imply a common source or behavior in regard to geogenic or anthropogenic influences. it was found that difference between the northwestern croatia and southern dalmatia is not expressed only by concentration differences but also by element associations. five factor models accounting most of the data variability seemed appropriate to portray the geochemical variability within the topsoil of both regions. 54 geologia croatica 54/1 differences in bedrock geology and the origin of the soil cover, as is the case in the mediterranean region of croatia. in the region of southern dalmatia the geochemistry of the topsoil cover distinguishes between the two major environments; the southern adriatic islands (mljet, korëula, hvar, and braë to some extent) and the mainland which consists of the two somewhat less pronounced environments: alluvial valleys-karst poljes and carbonate bedrock (peh & miko, 1999). 2. geology and pedology the north-western part of croatia (æumberak mt., pokuplje, posavina upstream of sisak, medvednica mt., hrvatsko zagorje, podravina to the east of varaædin, and meimurje) is bordered to the west and north by the croatian-slovenian borderline, to the south by the river kupa, and to the east by the gauss map y coordinate line of 5612500 (approximately the line connecting the cities of »akovec and sisak). the southern croatian territory is bounded to the west by the line extending from split to the peruëa lake. its northern fringe is defined by the state boundary towards bosnia and herzegovina. to the east the area is narrowing against the montenegro border at the cape of oπtra (fig. 1). the investigated territories belong to different geotectonic complexes. the northwestern croatia fits into the supradinaric palaeodynamic unit with elements of alpine structures. this area is also known as the inner dinaride belt (herak, 1986; herak et al., 1990). on the other side, recent tectonic setting of the southern croatia is a consequence of the disintegration of carbonate platform areas, which resulted in the extended, highly elevated karstic terrain, also known as the outer dinarides. the complex geotectonic evolution of these belts is reflected in prevalence of “non-carbonate” lithology in nw croatia, while its southern portions are built chiefly of carbonate sedimentary rocks. in the former case a variety of rocks occurs ranging from devonian (silurian?) to quaternary ages. the main bodies of the mountain ranges æumberak, medvednica, kalnik, ivanπëica, and some other smaller ranges, which are a minor part of the whole region of nw croatia, consist mainly of palaeozoic and mesozoic rocks (para-metamorphic rocks, ortho-metamorphic rocks, carbonate sedimentary rocks, igneous rocks and clastic sedimentary rocks). a major portion of this territory consists of tertiary rocks (limestones, marls, clastites, igneous rocks) and quaternary rocks (mostly alluvium sediments of the rivers sava, drava, mura, kupa, and their tributaries) (fig. 2). the geological setting of the southern part of croatia area resulted from a vigorous tectonic activity since the palaeozoic times. in its western part structures appear more compact, while to the east they display strong neotectonic faulting and partitioning into the minor blocks. throughout the area limestones and dolomites prevail which, due to tectonics and later karstification, manifest various karstic phenomena. the clastic flysch-type sedimentary rocks, mostly marls, also occur, although in a rather limited quantity. the occurrence of other siliciclastic rocks, outside the flysch complex, is extremely rare and related only to the palaeozoic tectonic windows far to the northwest. the stratigraphic sequence can be traced from the palaeozoic to the quaternary (fig. 2). the investigated areas are considerably contrasted not only by their geological settings but also in their climatic characteristics, which resulted in formation of the variety of soil types. most soils in the northern part of croatia (fig. 3) are characterized by high moisture content as a consequence of high precipitation, flooding and high groundwater levels. water can saturate the upper part of the horizon inducing the waterlogged conditions, which induce the development of hydro-morphic soils (©kori∆, 1986). in contrast, the southern parts of the country are covered by soils that are moistened only by the precipitation input, without additional saturation. infiltration through the soil and into the ground is free and unimpeded. the major area of the nw croatia is covered by soils from the group of gleys such as eutric, mollic and calcic gleysols (©poljar, 1999). these can be found in the valleys of the rivers (sava, drava, mura, sutla, krapina, and kupa). the second most frequent group of soils consists of stagnic and podzololuvisols, which cover the plains between æumberak mt., vukomeriëke gorice and zagreb as well as along the sava river downstream to the town of sisak. besides, these soils are spread in the belt between the sava river on the one side, and ivanπëica, kalnik and moslavaëka mountains on the other. the third major soil group, represents the mollic and calcaric fluvisols, particularly in the wide valleys of the sava and drava rivers immediately along their course. more rarely other types of soils occur, such as rendzic, mollic, umbric and dystric leptosols; eutric, dystric, humic and chromic cambisols; and albic, gleyic and chromic luvisols. about 2% of the collected samples belong to the urban areas of zagreb, sisak and varaædin. in contrast to the northern croatia, the karst bedrock in the southern dalmatia is dominantly covered by the coloured soils, terra rossa chromic cambisols, which cover the largest part of the coastal terrain and most of the islands. the next important group of soils consists of rendzic and mollic leptosols, which can be traced in the highest mountain reaches of the mosor, biokovo and dinara mountains as well as on the most elevated areas of the island of braë and the peljeπac peninsula. besides, these soil types cover a narrow strip of the coastal area from split eastward to ploëe. minor patches of the territory are overlain by the more rare soil varieties such as aric anthrosols (sinjsko polje, the zone along the neretva river, and portions of the islands of braë, hvar and korëula), mollic and calcaric fluvisols 55miko, halamiê, peh & galoviê: geochemical baseline mapping of soils... fig. 1 map of croatia with location of studied areas (northwestern croatia and southern dalmatia). 56 geologia croatica 54/1 fig. 2 geological map of croatia (veli∆ & veli∆, 1993). 57miko, halamiê, peh & galoviê: geochemical baseline mapping of soils... fig. 3 the soil map of croatia (modified from ©kori∆, 1986). (imotsko and vrgoraëko polje together with the valley of neretva), chromic luvisols (smaller area between the imotsko and sinjsko polje); and fibric and terric histosols (the swampland along the neretva river). much of the soils on flysch bedrock, and more rarely, on carbonate terrains are anthropogenized and transformed into rigosols. 58 geologia croatica 54/1 3. materials and methods 3.1. sampling and sample preparation soil samples from coastal and inland terrains were collected at a density of 1 site/25 km2 in a regular grid with the initial point of the grid for the whole country located in istria near the city of rovinj (pirc et al., 1991). detailed protocols of the sampling procedures to be applied for this region are given by pirc et al. (1991), and prohi∆ et al. (1997, 1998), as well as by miko et al. (1999), peh & miko (1999), halami∆ & galovi∆ (1999). all of the above protocols are summarized in the guidelines for the geochemical mapping of croatia (halami∆ et al., 2000), which only slightly differ from the recommendations given by darnley et al. (1995). the tolerated dislocation of sampling from the sampling cell nodes was 5%. in northwestern croatia a total of 293 soil samples were collected which is equivalent to a surface of approximately 7,350 km2, in southern dalmatia 404 (225 on the 5x5 km grid and 179 on the 1x1 km grid) soil samples collected cover an approximate surface of 5,600 km2 (fig 1). the soil samples were taken at each sampling site from 5 shallow pits (the amo-mollic horizon, from the depth of 0 to 20 cm) and one composite sample was prepared from each sampling site. 3.2. analytical procedures and quality assurance the dry soil samples were sieved to pass 63µm screen and were analyzed after near total (a hot acid mixture: h c l o4h n o3-hcl-hf at 200°c) decomposition for 35 elements by icp-aes in the acme labs in vancouver. the following elements were analyzed: ag, al, as, au, ba, bi, be, ca, cd, co, cr, cu, fe, la, k, na, nb, ni, mg, mn, mo, p, pb, sc, sb, sn, sr, ti, th, u, v, w, y, zn, and zr. the analytical results for ag, au, bi, be, mo, sb, sn, u and w were not used since more than 80% of the samples contained concentrations of these elements below the instrumental detection limits. single element geochemical maps were constructed only for the remaining elements with concentrations above the detection limit (usually more than 90% of the analyzed samples). accuracy of analyses was controlled with the aid of certified geological reference materials, i.e. soils from the usgs; gxr-2, gxr 5, and sjs-1. the accuracy for most elements analyzed in reference soil materials is in the range of ±10 % of the certified values (peh & miko, 1999; halami∆ & galovi∆, 1999). the precision of the analyses was determined by repeated analysis of both certified reference samples and randomly selected soil samples, the resulting coefficient of variation in average is approximately 5% (peh & miko, 1999; halami∆ & galovi∆, 1999). the field data and the chemical analyses are stored as a database, which besides the chemical data also contains 20 parameters that describe topographic, geologic, geomorphologic and pedologic features of the sampling sites and samples. all collected samples are preserved and stored for future use. the single-element geochemical maps were produced with the aid of the surfer mapping software. griding was performed by linear kriging (isaaks & sirvastava, 1989) with grid cell resolution of 2 x 2 km. 3.3. evaluation of basic statistical parameters and multivariate statistics the evaluation of basic statistical parameters for all elements was performed on the analytical data from the whole database. these parameters are given in table 1, while others are displayed together with frequency distribution histograms presented on each individual map. also the nonparametric distributions of each element are given as the 10th, 25th, 50th, 75th, 90th, 95th, 98th and 99th percentile values, which are present as elemental concentration distribution contour boundaries on the maps. for decades both exploration and environmental geochemical studies frequently use r-mode factor analysis as a multivariate mathematical technique to reveal the underlying structure of a specific set of data (davis, 1986). as such, it is commonly used as a tool of data reduction, with a purpose of clearer insight into the basic relationships among variables (r-mode), or among samples (q-mode). a simply structured factor model, which contains only a few heavily loaded factors, is always indicative of the strong dependence among elements, and therefore as such, is used to compare the geochemistry of the studied regions. factor analysis was performed for the data set of each region separately with the aim to observe similarites of geochemical behavior of the analyzed elements and to allow a more straithgfoward insight into the structure of the data. all statistical analyses were performed with the statistica software. 4. results and discussion 4.1. element distributions in the secondary environments the geochemical background varies regionally with the basic geology, as is indicated by the results of geochemical mapping performed in the panonnian and the karst regions of croatia. the results of the geochemical baseline mapping program together with the accompanying full data bases for nw croatia and southern dalmatia is summarized in atlases of single element maps (halami∆ & galovi∆, 1999; peh & miko, 1999; miko et al., 2001). the summary statistics for croatian soil geochemical data obtained so far during the geochemical mapping program is given in table 1. for comparison 59miko, halamiê, peh & galoviê: geochemical baseline mapping of soils... the mean concentrations of elements in slovenian soil (andjelov, 1994) are also presented since the data were obtained in the same manner (sampling and analytical procedures were the same). also for a clearer insight a comparison of the distribution of both major and trace elements in the analyzed soils is given on box and whisker-plots in figs. 4 (major elements) and 5 (trace elements). from the summary data in table 1 it is visible that most of the elements (al, as, co, cu, fe, la, pb, ni, mn, th, v, cr, zn, zr and nb) have higher median values in soils developed on carbonate bedrock with the exception of na, k, fe and ba, which have higher concentrations in soils of the northwestern part of croatia. sr, p, mg, and ti manifest a similar range of contents in both regions. the non-outlier ranges in figs. 4 and 5 show that the trace elements have the largest variability of content in soils developed on carbonate bedrock in southern dalmatia, while the variation in northwestern croatia is far less expressed. the samples from western croatia (the regions of gorski kotar, lika and kordun in general, miko et., al., 2001) have elements of a transition zone since the soils that are developed on the limestones on the karlovac plateau are derived (as a result of aeolian transport) from material that originates from the northwestern croatia. this is expressed by an intermediate variation between the other two geographically distant and geologically different regions. the relatively small variation in the content of trace elements in soils of northwestern croatia is probably due to the relatively limited area that was sampled. the major elements (fig. 4) in all regions show a similar degree of variation. a short description of the individual elements presented and corresponding geochemical maps is given in the text that follows. aluminium (al) aluminium content in soils (plates 1 & 2) is mainly controlled by the clay content, the parent lithology and the content of carbonates, which is best illustrated on the plot cao vs. al2o3 in fig. 6. the data for western croatia are given for comparison (miko et al., 2000, 2001). aluminum ranges from 1.46% to 10.84% with an arithmetic mean of 6.89% in northwestern croatia whereas in southern dalmatia its contents range from 0.82% to 14.04%. the lowest aluminum contents are found in soils that contain higher carbonate contents such as rendzinas on dolomites and limestones, soils developed on flysch bedrock and on carbonate rich nw croatia s dalmatia croatia slovenia (andjelov, 1994) # samples median median median mean mean al (%) 1143 7.33 7.94 7.32 7.23 6.69 as (mg/kg) 984 14 14 12 14 8.17 ba (mg/kg) 1151 330 279 326 345 371 ca (%) 1153 1.24 2.29 1.41 3.77 2.58 co (mg/kg) 1152 14 18 15 15 28 cr (mg/kg) 1153 94 112 96 104 90 cu (mg/kg) 1153 34 45 34 49 28 fe (%) 1153 3.67 4.13 3.67 3.68 3.75 hg (mg/kg) 293 60 60 94 k (%) 1024 1.21 1.21 1.36 1.34 1.23 la (mg/kg) 1151 49 50 43 45 31 mg (%) 1152 0.68 0.82 0.75 1.09 1.35 mn (mg/kg) 1153 780 1009 770 844 1044 na (%) 1151 0.49 0.28 0.43 0.51 0.52 ni (mg/kg) 1153 59 79 59 65 53 p (%) 1024 0.062 0.071 0.064 0.076 0.07 pb (mg/kg) 1153 43 53 42 46 38 sc (mg/kg) 1023 11 12 11 11 13 sr (mg/kg) 1153 86 102 98 120 98 th (mg/kg) 1024 13 17 13 14 11 ti (%) 1153 0.40 0.41 0.41 0.39 0.38 v (mg/kg) 1153 118 143 117 125 118 zn (mg/kg) 1153 91 109 94 101 113 table 1 summary statistics for the analyzed elements in topsoils from croatia (data from western croatia from miko et al., 2001). 60 geologia croatica 54/1 alluvium deposits along the sava river near zagreb, or in karst poljes which contain lacustrine sediments. higher contents of al are found in soils overlying magmatic and metamorphic rock complexes. in the region of southern dalmatia the terra rossa soils regularly have more than 8% of al as a consequence of high clay content, while the alluvial and marsh soils due to dilution by carbonates have concentrations lower than 6%. the effect of carbonate dilution is best viewed on the plot cao vs. al2o3 (fig. 6). arsenic (as) the distribution and contents of arsenic (plates 3 & 4), which is considered a potentially toxic element, ranges in northern croatia from 1.8 to 52.7 mg/kg with an average of 10 mg/kg. the soils developed on carbonate bedrock in southern dalmatia have a similar range of contents but in average contain 16 mg/kg of as. in general there is a high correlation of as with the al content in soils indicating that the clay content controls the as content in the soils. therefore alluvial soils and soils derived from flysch have low contents of arsenic, while terra rossa has elevated concentrations of as. although most of the high concentrations of as can be linked with the underlying lithology in areas of intensive agriculture (meimurje), agrochemicals as a source cannot be excluded. in æumberak mt. the as can partly be derived from the sulphide mineralization that occurs in the region. barium (ba) the barium content (plates 5 & 6) in the analyzed soils from both regions ranges from 40 to 3,000 mg/kg. barium has a geochemical affiliation for potassium (fig. 7), especially in feldspar, so the weathering products also retain this relationship. high concentrations of ba were found in æumberak mt., where it is related to sulphide mineralization. in some parts of alluvial plains of the rivers sava (near sisak), drava and krapina the contents of ba exceed 500 mg/kg. the mean ba content of fig. 4 concentration ranges of major elements in soils from southern dalmatia, western croatia and northwestern croatia, median; non-outlier minimum, non-outlier maximum (data for w croatia from miko et al., 2000, 2001). fig. 5 concentration ranges of minor and trace elements in soils from southern dalmatia, western croatia and northwestern croatia, median; non-outlier minimum, nonoutlier maximum (data for w croatia from miko et al., 2000, 2001). 61miko, halamiê, peh & galoviê: geochemical baseline mapping of soils... soils from the pannonian part of croatia is 424 mg/kg, whereas from southern dalmatia is 324 mg/kg. soils developed on carbonate clastic rocks and alluvial and marsh soils in the karst regions have ba contents below 200 mg/kg, which also reflect the effect of carbonate dilution. the analysis of ba data of soils (miko et al., 2000) for the adriatic islands mljet, korëula, hvar and braë indicate enrichment of this element, as do the recent sediments from the southern part of the adriatic sea (dolenec et al., 1998). barium together with k and na, seems to be the key element that determines the geochemical provinces in croatia, which are the karst region, with low contents of these elements, the transition zone of the karlovac plateau, and northwestern croatia with high concentrations of ba, k and na. calcium (ca) calcium (plates 7 & 8) as a major element and nutrient ranges from 0.07 to 14.70% in northwestern croatia, and from 0.39% to 35.09% in southern dalmatia with mean concentrations of 2.08% and 6.02% respectively. the lowest concentrations of ca were determined in soils developed on loess deposits and gleyic soils in northwestern croatia and in southern dalmatia in terra rossa and brown soils developed on limestones. rendzinas developed on limestone, dolomite and flysch due to the large amount of fine carbonate detritus regularly contain more than 3% of ca. the effect of dilution by carbonates is illustrated by the scatter plot cao-al2o3 in fig. 6. high calcium contents characterize soils developed on floodplain sediments of the rivers sava, drava, neretva and the karst poljes imotsko polje and vrgoraëko polje that are also flooded in spring periods and whose floors contain lacustrine type of sediment. cobalt (co) the distribution of cobalt (plates 9 & 10) is in high correlation with the distribution of al, fe and mn, indicating the effects of coatings of iron and manganese hydroxides on clay mineral surfaces. the content of co fig. 6 the relationship between the contents of cao and a l2o3 (data for w croatia from miko et al., 2000, 2001). fig. 7 the relationship between the contents of k and ba (data for w croatia from miko et al., 2000; 2001). 62 geologia croatica 54/1 ranges from 2 to 38 mg/kg in both regions and the mean contents in northern croatia is 12 mg/kg and in southern dalmatia 17 mg/kg. the highest contents of cobalt occur in terra rossa with high iron and manganese content in southern dalmatia. in northern croatia the high concentrations of cobalt are also controlled by bedrock lithology with elevated values in soils developed on basic and ultrabasic magmatic rocks as well as on cretaceous flysch deposits. chromium (cr) the concentration of chromium (plates 11 & 12) in soils ranges from 32 to 524 mg/kg with a mean value of 83 mg/kg in northwestern croatia, whereas in southern dalmatia range from 15 to 2,200 mg/kg with a mean value of 126 mg/kg. the higher (>83mg/kg) concentrations of cr in fluvisols and gleys can be attributed to deposition on reducing geochemical barriers and high organic matter content in nw croatia while the high anomalies of over 500 mg/kg near zelina can be a consequence of chromite bearing ultramafic magmatic rocks and clastic rocks derived from older basic magmatic rocks. the highest concentrations of cr in the karstic regions are confined to three general environments: to terra rossa soils which contain redeposited bauxite fragments (wider region of sinjsko polje and imotski), the soils developed on eocene flysch and the soils developed on quaternary sands (mljet island and korëula island). both the eocene flysch and quaternary sands are probably partly derived from basic or ultrabasic rocks. the influence of clays on cr distribution is shown on the cr vs. al2o3 plot on fig 8. copper (cu) the content of copper (plates 13 & 14) in soils ranges from 5 to 248 mg/kg with a mean value of 26 mg/kg in northwestern croatia, while in southern dalmatia it ranges from 6 to 923 mg/kg, with the mean value of 67 mg/kg. copper is a potential risk element and most of the elevated concentrations cannot be correlated with a certain soil type but more to agricultural activity especially the vicinity of vineyards (the application of pesticides based on copper sulphate). the anthropogenic influence on cu distribution is shown on the cu vs. a l2o3 plot on fig. 9 indicating a divergence of data from the general cu/al trend. iron (fe) iron content in soils (plates 15 & 16) is mainly controlled by its clay content, the parent lithology and the content of carbonates just as in the case of al. this link is stressed by high correlation (r=0.92, tables 2 and 3) of the two elements and the similarity of distribution maps (see plates 1 & 2). iron contents range from 0.60% to 6.43%, with a mean value of 3.28% in northwestern croatia while in southern dalmatia its contents range from 0.43% to 35.0%, with a mean value of 3.94%. the lowest fe concentrations, just as in the case of al, are found in soils that contain higher carbonate contents such as rendzinas on dolomites and limestones, soils developed on flysch bedrock and on carbonate rich alluvium deposits along the sava river near zagreb, or in karst poljes which contain lacustrine sediments. in the region of southern dalmatia the terra rossa soils regularly have the highest fe contents >4.5%, while the alluvial and marsh soils due to dilution by carbonates have concentrations lower than 3%. lanthanum (la) the la content in soils (plates 17 & 18) seems to be mainly controlled by its clay content, and it correlates well with elements of geochemically similar behavior such as th, and sc (r=0.6). the correlation (r=0.45) with al is rather low but the general trend indicates the importance of al. the concentration of la in soils ranges from 9 to 54 mg/kg with a mean value of 34 fig. 8 the relationship between the contents of cr and al2o3 (data for w croatia from miko et al., 2000, 2001). 63miko, halamiê, peh & galoviê: geochemical baseline mapping of soils... mg/kg in nw croatia, whereas in southern dalmatia ranges from 4 to 109 mg/kg and the mean value of 48 mg/kg. the effect of dilution by carbonates is also evident in the distribution of this element; and the contents of la are highest in terra rossa and have mean values of 60 mg/kg which is similar to the values given by durn (1996) for istrian terra rossa. lead (pb) the concentration of lead (plates 19 & 20) in soils ranges from 15 to 382 mg/kg with a mean value of 34 mg/kg in northwestern croatia, whereas in southern dalmatia range from 9 to 220 mg/kg and the calculated mean value is 52 mg/kg. there is a significant difference in the content of pb in soils developed on carbonate terrain and those on non-carbonate terrains. in carbonate terrains the rendzina types of soil have higher than average contents (>60mg/kg). the effect of carbonate dilution is obvious in soils developed on clastic rocks and alluvial sediments which have low pb contents ranging from 20 to 30 mg/kg. higher contents of lead are also linked to higher altitudes; a similar distribution pattern impact is also encountered in mountain regions of western croatia (miko et al., 2000, 2001). the anomalous lead concentrations in southern dalmatia can be attributed partly to traffic but the influence of war activities at the beginning of the 1990s cannot be excluded. the anomalous lead concentrations were found in soils developed on the floodplain sediments of the drava river. the source of the lead can be traced to the pb-zn mining regions (meæica, bleiburg) located in the upper coarse of the drava river in neighbouring slovenia and austria. most of the other areas in northwestern croatia that display elevated contents of pb can be mainly traced to past mining activities and pb-znore occurrences; possible car traffic influences cannot be unequivocally recognized on a regional scale. potassium (k) potassium content in soils (plates 21 & 22) ranges from 0.33% to 3.28%, with a mean value of 1.66% in northwestern croatia, whereas in southern dalmatia its contents range from 0.12% to 2.89%, with a mean value of 1.20%. the content of potassium in soils is besides na and ba the major element that discriminates the soils developed in the karst region and the soils from northwestern croatia. in fig 10, a s-n profile from the adriatic coast (loπinj and cres islands, through the regions of gorski kotar to meimurje in the north, shows a northward increasing trend in the content of these two elements. the increase is most evident to the north from the sava river, which is also very similar with k distribution in slovenian soils (andjelov, 1994). in southern dalmatia the highest k contents are present in terra rossa and soils developed on flysch, and in soils developed on the southern/southwestern parts of the islands hvar, korëula and mljet. high k contents were also found in recent marine sediments (dolenec et al., 1998) in the region of these islands. sodium (na) the contents of the sodium (plates 23 & 24) are higher in nw croatia and range from 0.11% to 3.21%, with a mean value of 0.83%; in southern dalmatia its contents range from 0.01% to 1.04%, with a mean value of 0.29%. the content of sodium together with ba and k is the major element that discriminates the soils developed in the karst region and the soils from the pannonian basin. although the distribution pattern of sodium in soils (plates 21 & 22) is similar to potassium in northwestern croatia (a trend increase towards the north from the sava river) there is an absence of significant correlation between the two elements (r=0.1), whereas in southern dalmatia the correlation (table 3) is significantly higher (r=0.63). the lowest concentrations of na in the karst terrains are found in soils develfig. 9 the relationship between the contents of cu and al2o3 (data for w croatia from miko et al., 2000, 2001). 64 geologia croatica 54/1 oped on marls, while the highest accumulations are present in marsh sediments. in general the drained soils (developed on limestone) have the lowest na contents in both regions. the highest concentrations of na occur on soils developed on ortho-greenshists and spilitized basic rocks (medvednica mt.) in nw croatia, these rocks seem to be an important source for pliocene sediments that occur on the slopes of mt. medvednica, because the soils developed on these rocks have a similar distribution pattern as ti (the correlation coefficient for nw croatia is 0.62). elevated na contents are present in all soils that lie between the rivers mura and drava. the differences in contents of na between the regions are presented in the na vs. k plot in fig. 11. magnesium (mg) magnesium (plates 25 & 26) as a major element and nutrient plays an important role in the chemistry of the table 2 the correlation matrix for the geochemical soil data from northwestern croatia (n=293). 65miko, halamiê, peh & galoviê: geochemical baseline mapping of soils... analyzed soils. its contents range from 0.23 to 7.52% in northwestern croatia and from 0.82% to 9.24% in southern dalmatia, with mean concentrations of 1.44% and 1.19% respectively. the lowest concentrations of mg were determined in soils developed on loess deposits and gleyic soils in northwestern croatia and in southern dalmatia in terra rossa and brown soils developed on limestones. rendzinas developed on dolomite due to the large amount of fine dolomitic detritus regularly contain more than 1.5% of mg. the scatter plot cao-mgo (fig. 12) shows the variation of these elements in the analyzed soils in accordance with their dolomite and calcite content (compositions of normative dolomite from ebens & connor, 1980). high magnesium contents characterize soils developed on floodplain sediments with abundant dolomite of the rivers sava, drava, and neretva. table 3 the correlation matrix for the geochemical soil data from southern dalmatia (n=404). 66 geologia croatica 54/1 manganese (mn) the concentration of manganese (plates 27 & 28) in soils ranges from 131 to 5,619 mg/kg with a mean value of 622 mg/kg in nw croatia, and from 96 to 2,563 mg/kg in southern dalmatia with the mean value of 971 mg/kg. in southern dalmatia higher than 1,000 mg/kg concentrations of mn occur in terra rossa, brown soils and rendzinas on limestones, as well as in soils developed on marls. the content of mn in this region is lowest (<500 mg/kg) in soils, which are for some periods saturated with water and where mobilization of mn in the soil profile is present. these are soils in large karst poljes and the floodplain of the neretva river. manganese hydroxides together with iron hydroxides play an important role in concentration of metals (mckenzie, 1989) and in the case of soils developed on carbonate bedrock there is a high correlation of mn with co (r=0.76) while elements such as cr, v, ni, pb and zn are preferentially concentrated by iron oxides (for mn r<0.5, for fe r>0.5). in nw croatia the highest concentrations of mn are found in the eastern parts of ivanπëica mt. and kalnik mt. probably as a reflection of mn deposits and occurrences. the alluvial soils in the valleys of the drava and mura rivers also have elevated contents of mn. nickel (ni) the distribution of nickel (plates 29 & 30) is similar to the distribution pattern of co and is in high correlation with the distribution of al, fe and mn, indicating the effect of coatings of iron and manganese hydroxides on clay mineral surfaces. the content of ni ranges from 13 mg/kg to 427 mg/kg, with a mean value of 42 mg/kg in nw croatia and in southern dalmatia its contents range from 7 to 288 mg/kg, with a mean value of 84 mg/kg. the high concentrations near zelina are a consequence of basic and ultrabasic magmatic bedrocks. these rocks are probably sources of ni in alluvial soils that occur in floodplains of rivers (central northwestern croatia) that drain this region. the highest concentrations of ni in fig. 10 the relationship between the contents of na+k and latitude. fig. 11 the relationship between the contents of na2o and k2o (data for w croatia from miko et al., 2000, 2001). 67miko, halamiê, peh & galoviê: geochemical baseline mapping of soils... the karstic regions are confined to three soil types, the terra rossa soils, the soils developed on eocene flysch (the wider region of dubrovnik) and the soils developed on quaternary sands (mljet island and korëula island). both the eocene flysch sedimentary rocks and quaternary sands are probably partly derived from weathering products of basic magmatic rocks. phosphorus (p) phosphorus (plates 31 & 32) contents range from 0.02% to 0.19%, with a mean value of 0.064% in northwestern croatia; in southern dalmatia its contents range from 0.012% to 0.68%, with a mean value of 0.08%. the lowest concentrations of p are found in soils of the islands korëula, hvar and mljet in southern dalmatia. the type of soil seems to have little influence on the content of p in the karst region since the variation and means are similar for all soil types; only soils on flysch (sandstones and marls) have in general lower p contents (<0.06%). in nw croatia there is also obvious correlation of p content and soil type but in general forest soils have the lowest (median = 0.04%) content and the arable soils the highest (median = 0.09%) content. the anthropogenic influence on the distribution of this nutrient is evident since highest concentrations are found in agricultural regions. scandium (sc) the sc content in soils (plates 33 & 34) is mainly controlled by its clay content, and it shows a high correlation with al and fe (r=0.9). geochemically it is considered a conservative element similar to al and is also often used for normalization procedures. the concentration of sc in soils ranges from 2 to 18 mg/kg with a mean value of 9 mg/kg in nw croatia, and in southern dalmatia it ranges from 4 to 34 mg/kg, with the mean value of 12 mg/kg. the effect of dilution by carbonates is also evident in the distribution of this element; the contents of sc are highest in terra rossa while the soils developed on marls and carbonate alluvial sediments have the lowest contents. strontium (sr) the distribution of strontium (plates 35 & 36) is similar in some aspects to the distribution pattern of ca. the dissimilarity occurs in soils developed on dolomite, since these soils contain high ca contents but lack strontium whose concentrations are low in dolomite and alluvial sediments containing dolomite. the content of sr ranges from 45 mg/kg to 1,090 mg/kg, with a mean value of 118 mg/kg in nw croatia; in southern dalmatia its contents range from 40 mg/kg to 476 mg/kg, with a mean value of 127 mg/kg. the high content of strontium is found in both regions in soils developed on tertiary lacustrine marls, on flysch bedrock, soft limestones and in alluvial valleys in the karst regions that during flooding have features of intermittent lakes (vrgoraëko polje). soils on dolomitic bedrock and terra rossa on limestone have low sr contents (<90 mg/kg). titanium (ti) titanium content (plates 37 & 38) ranges from 0.08% to 1.09%, with a mean of 0.39% in northwestern croatia, whereas in southern dalmatia its content ranges from 0.05% to 0.87%, with a mean of 0.37%. the lowest ti contents are found in soils that contain higher carbonate contents such as rendzinas on dolomites and limestones, soils developed on flysch bedrock and on carbonate rich alluvium deposits along the sava river near zagreb, or in karst poljes which contain lacustrine sediments. the high correlation (r=0.9) of ti with al and fe in soils from southern dalmatia (table 3) is indicative of similar processes of enrichment. in soils from nw croatia there is an absence of such relationfig. 12 the relationship between the contents of mgo and cao. dolomite = normative dolomite from ebens & connor, 1980) (data for w croatia from miko et al., 2000, 2001). 68 geologia croatica 54/1 ships (al vs. ti r=0.37; fe vs. ti r=0.24; table 2), and the highest contents of ti are confined to gleys developed on loess, and in marshlands. the highest contents of ti are found in soils overlying basic magmatic and ortho-greenschist metamorphic complexes on medvednica mt. the distribution differences between the karst region and the pannonian region is illustrated on the plot ti vs. al2o3 in fig. 13. thorium (th) the concentration of th in soils (plates 39 & 40) ranges from 2 to 17 mg/kg with a mean value of 11 mg/kg in nw croatia, whereas in southern dalmatia it ranges from 2 to 29 mg/kg, with the mean value of 16 mg/kg. the thorium content in soils has a high correlation with al and fe (r=0.8 in southern dalmatia, r=0.7 in nw croatia). the effect of dilution by carbonates is also evident in the distribution of this element, and the contents of th are highest in terra rossa while the soils developed on marls and carbonate alluvial sediments have the lowest contents. vanadium (v) the content of vanadium in the analyzed soils (plates 41 & 42) ranges from 22 to 238 mg/kg, with a mean value of 101 mg/kg in nw croatia; whereas in southern dalmatia its contents range from 16 mg/kg to 386 mg/kg, with a mean value of 142 mg/kg. the distribution of v similar to the distribution patterns of al and fe (r=0.9) indicates the role played by coatings of iron hydroxides on clay mineral surfaces (schwertman & taylor, 1989). the highest contents of v similar to ti are found in soils overlying basic magmatic and ortho-greenschist metamorphic rock complexes on medvednica mt. the highest concentrations of v in the karstic regions characterize the terra rossa, while soils developed on eocene flysch (the wider region of dubrovnik) and the soils developed on quaternary sands (mljet island and korëula island) as well as alluvial (with carbonates) soils have low concentrations of vanadium. zinc (zn) the content of zn (plates 43 & 44) ranges from 28 mg/kg to 974 mg/kg, with a mean value of 92 mg/kg in nw croatia; in southern dalmatia its contents range from 16 to 491 mg/kg, with a mean value of 113 mg/kg. there is a significant difference in the behavior of zn in soils developed on carbonate terrain and those on noncarbonate terrains. in carbonate terrains zn is controlled by the clay content (zn-al correlation coefficient r= 0.48, table 3) and higher contents are the characteristic of rendzina type of soils as well as of soils developed at higher altitudes (<140 mg/kg), which is similar to the distribution of pb (r=0.47). the effect of carbonate dilution is obvious in soils developed on clastic rocks and alluvial sediments, which have low zn contents (<75 mg/kg). anomalous lead concentrations in nw croatia are found in soils developed on the floodplain sediments of the drava river. the sources of the zn, as in the case of pb (r=0.96, table 2) can be traced to the pb-zn mining regions (meæica, bleiburg) located in the upper course of the drava river in neighbouring slovenia and austria. most of the other areas in northwestern croatia that display elevated contents of pb can be mainly traced to past mining activities and pb-zn ore occurrences, although other possible anthropogenic influences cannot be unequivocally recognized, especially in the lower course of the sava river. mercury (hg) the content of mercury at this stage of investigation was determined only in soils from northwestern croatia (pl. 45). the hg concentrations range from values below 10 µg/kg to 4,535 µg/kg, with a mean value of fig. 13 the relationship between the contents of ti and al2o3 (data for w croatia from miko et al., 2000, 2001). 69miko, halamiê, peh & galoviê: geochemical baseline mapping of soils... 94 µg/kg. the highest concentration of 4,535 µg / k g was measured in soils developed on limestone from a location on kalnik mt. the sources of this high hg contents, as well as the high contents on the neighboring ivanπëica mt. are probably a consequence of mineralization occurrences. urban soils in general have higher hg contents especially in the cities of zagreb and varaædin. high contents of hg in urban soils of zagreb were also determined by namjesnik et al. (1992) and palinka© et al. (1996); in a study by miko et al. (1992) it was determined that the hg is derived from fossil fuel consumption (coal). the elevated hg contents in soils developed on the sava river floodplain sediments is a consequence of material derived from the litija mining region which produced 150 t of hg from 1880 to 1965 (mlakar, 1993). the soils of the region of samoborska gora mt. (rude) also contain elevated hg contents as a response of base metal sulphide mining and occurrences of mineralization. 4.2. geochemical associations and environmental applications geochemical baselines are principally useful for the determination of environmentally significant contents of elements for the evaluation of pollution sources. since the variation of geology at a regional scale influences the geochemical background considerably the definition of these values must be performed in a correct manner. there are various approaches in use depending on the type of data, media, and analytical techniques (darnley, 1995; salminen & tarvainen, 1997; bodi© & rapant, 2000). the legislative approach uses the geochemical data for comparison with defined environmental thresholds as in the netherlands (van lienen et al., 2000) or the intervention criteria in italy as used by de vivo et al. (1998). today in croatia only agricultural thresholds for ten potentially toxic elements (pb, as, cd, co, ni, zn, cu, hg, mo and cr) (narodne novine, 1992) exist which were derived from a small data set and compiled from regulations of other countries. the human impact on soils can be also evaluated by calculation of enrichment factors (hassan & ismail, 1993). the enrichment factor (ef) is the concentration ratio of an element in each individual sample ( cn s a m p l e) and the conservative element (usually al, ti, sc) in the sample (c cons.sample), in respect to same ratio of element and the conservative element in a reference material cn ref./ ccons. ref. (förstner & wittmann, 1981; li, 1981): ef = (cnsample/ccons.sample ) / (cn ref./ccons. ref.) the definition of the enrichment factor indicates that this parameter depends on the choice of reference element and the choice of reference material. the influence of referent element choice upon the value of enrichment factor is discussed in papers of numerous authors, but al is the commonest in use and its correlation with the clay content in sediments and soils, is well established (windom et al., 1989; durn et al., 1999) and has been quite frequently applied in the karst regions of croatia (prohi∆ et al., 1995, 1998; miko et al., 1999). according to the criteria of golchert et al. (1991) who distinguish three categories of the enrichment factors: ef≤2, 2<e f<1 0 and ef≥10, where ef lower than 2 indicates a natural variation of an element and those higher than 10 indicate severe pollution, miko et al. (2000) determined moderate (2<ef<10) pb pollution of soils in western croatia as a consequence of acid rain deposition. the calculated enrichment factors for pb for the whole data set show that 50 sampling sites have efs higher than 2, of which 25 are situated in the region of western croat ia and within the risnjak national park, i.e. approximately 4% of the sites can be considered as moderately enriched (polluted) either from mining activities or airborne deposition. only a limited number of sampling sites can be directly linked with mineralization. this calculation of pb enrichment factors is based on the median values of pb (42 mg/kg) and al (7,32 %) for the whole data set as the reference material. due to significant concentration differences of pb in soils developed on carbonate bedrock (48 mg/kg) and non karstic terrain (30 mg/kg), an universal reference material for the whole territory of croatia was found not to be appropriate in this case, since it would give an underestimate or overestimate of the ef as in the case of pb (fig. 14). statistical analysis has been frequently employed both in exploration geochemistry and environmental geochemistry for determination of baseline values and as a tool for distinguishing between geogenic and anthropogenic effect. most frequently used are those techniques based on correlation coefficients such as cluster analysis and factor analysis. the later was applied by authors in the neighbouring countries (de vivo et al., 1997; 1998a; ©ajn et al., 1998) and in croatian karst regions (prohi∆ et al., 1997, 1998; miko et al., 2000). the derived factors are usually interpreted as associations of elements that imply a common source or behavior in regard to geogenic or anthropogenic influences. in our case, it was found that difference between the northwestern croatia and southern dalmatia is expressed not only by concentration differences but also by element associations. element associations in southern dalmatia a five-factor model accounting for 74% of the data variability seemed appropriate to portray the geochemical variability within the topsoil in southern dalmatia. the th, al, fe, ti, (-ca), v, pb, ba, mn, and la factor (table 4) accounts for 38% of the total data variability. the factor scores distribution patterns show the low values for soils developed in alluvial plains, dolomites and flysch bedrock (high concentrations of ca), while the high values correspond to brown soils on 70 geologia croatica 54/1 limestone, and terra rossa. this element association is the major geogene association of soils developed on croatian karst (prohi∆ et al., 1998; miko et al., 1999, 2000) and can be termed as the clay factor. the most interesting association in a geogene sense is the k-na-(ba) factor (factor 2) with high scores associated with soils on the adriatic islands of mljet, korëula and hvar, and slightly lower values on the island of braë and the peljeπac peninsula. high concentrations of the elements of factor 2 were also observed in surficial sediments from the southern part of the adriatic sea by dolenec et al. (1998). the association of elements and its spatial distribution implies an aeolian influence connected to the development of soils on mainly aeolian quaternary sediments, whose source was probably the po river plain; although some analysis of deeper profiles on the western part of korëula island have shown extremely high contents of na, k, ba, la, sr and th indicating tephra type of material deriving possibly from italian volcanos (vesuvius). a detailed mineralogical analysis is yet to prove this asumption. factor 3 with high loading for cr, ni, co, and cu is hard to interpret unequivocally because in some regions it might reflect possible bauxitic influence while in others, it reflects probably mafic components of weathered clastic materials (mainly flysch deposits and sands derived from these deposits eastern parts of korëula and mljet islands). the association of elements (p, zn, altitude and pb) loaded on factor 4 is interpreted as reflecting an anthropogenic source for zn, p and pb. this is very similar to the mountainous karst regions of western croatia (risnjak national park and the velebit massif) where a similar distribution pattern is also present (miko et al., 2000, 2001). the high positive scores that correlate positively with altitude are interpreted as a consequence of acid rain deposition; a very similar association of elements is found in the mountainous regions of central europe (matschullat & bozau, 1996). factor 5 (sr, mg) spatially corresponds to soils developed on lacustrine sediments in karst poljes and the marl deposits that surround the sinj polje. fig. 14 the range of pb enrichment factors in soils from different regions in croatia. factor factor factor factor factor 1 2 3 4 5 al 0.91 fe 0.87 ca -0.81 ti 0.88 mn 0.56 ba 0.64 0.58 v 0.76 th 0.93 as 0.45 la 0.48 pb 0.68 0.47 k 0.88 na 0.91 cr 0.63 ni 0.84 cu 0.66 co 0.64 p 0.87 altitude 0.54 zn 0.50 mg -0.72 sr 0.67 expl. var 8.38 2.34 2.74 1.47 1.42 prp. totl 0.38 0.11 0.12 0.07 0.06 table 4 varimax rotated factor matrix for the topsoil geochemical data from southern dalmatia (n= 404). 71miko, halamiê, peh & galoviê: geochemical baseline mapping of soils... element associations in northwestern croatia the geochemical variability within the topsoil in northwestern croatia can also be described by a five-factor model, which accounts for 71% of the data variability. although there is some similarity in the element associations, there are also some significant differences and none of the element associations dominate. the weathering of basic magmatic rocks and ortho-greenschists seem to be an important supply of material for both older sedimentary rocks and recent soils in the region which resulted in a corresponding suite of elements comprising ni, cr, co, fe, v and as (factor 1, table 5). this factor accounts for 18% of the data variability, and is similar to factor 4 (al, th, k, la and ba) with high factor scores related to eugleys (marsh soils). the factor 2 has high positive loadings for mg and ca and coincides with the dilution effect caused by the presence of dolomite in alluvial soils and rendzinas developed on dolomite. the negative loadings of ti and na on this factor is a result of dilution by the former elements and their common source. this factor accounts for 13% of the data variability. the pb-zn (factor 3) association also accounts for 13% of the data variability and is a consequence of secondary dispersion from mining activities (floodplain of the drava river) and sulphide ore occurrences in the mountainous regions. the pollution effects caused by human activities (besides mining) cannot be unequivocally deduced especially in the floodplain regions that are both urbanized (zagreb, karlovac and varaædin) and have in the past been flooded by waters that drained various mining regions. factor 5 (mn, cu, p and sr) accounting for 10% of the total data variability, correlates especially well with arable soils and wine producing areas. 5. conclusions the results of geochemical baseline mapping performed in two different parts of the croatia whose soils originated on different geological substrates, 1) predominantly non-carbonate terrains (northwestern croat ia) and 2) predominantly carbonate terrains (southern dalmatia), show that al, as, co, cu, fe, la, pb, ni, mn, th, v, cr, and zn have higher median values in soils developed on carbonate bedrock, with the exception of na, k, fe and ba, which have higher concentrations in soils of the pannonian part of croatia. the relatively small variation in the content of trace elements in soils of northwestern croatia is probably due to the relatively limited area that was sampled and was also confirmed by different element associations in the two regions. the application of different techniques on the geochemical data set for the determination of environmentally significant contents of elements in order to evaluate the pollution sources must be in the future viewed in accordance with geological variability of croatia. since the variation of geology at a regional scale influences the geochemical background considerably the definition of these values in future will be assessed when geochemical mapping at this density is concluded for the whole country. acknowledgments this study was funded by the ministry of science and technology of the republic of croatia within the frame of the project # 01810106, “ the basic geochemical map of the republic of croatia”. special thanks are extended to mr sc. –uro ben»ek and dr sc. josip beni∆ from the institute of geology, who supported the preparation of this paper. 6. references andjelov, m. (1994): results of radiometric and geochemical measurement for the natural radioactivity map of slovenia.geologija 36, 223-248, ljubljana. bodi©, d. & rapant, s. (2000): environmental geochemistry and environmental geochemical mapping of the slovak republic.slovak geol. mag., 6/1, 5-16. factor factor factor factor factor 1 2 3 4 5 ni 0.88 cr 0.87 co 0.82 fe 0.66 v 0.58 as 0.57 mg 0.59 ca 0.69 na -0.79 ti -0.90 zn 0.94 pb 0.96 al 0.75 th 0.84 k 0.76 la 0.67 ba 0.45 mn 0.58 cu 0.53 p 0.57 sr 0.60 prp. totl 0.18 0.13 0.13 0.17 0.10 expl.var 3.88 2.85 2.87 3.63 2.13 table 5 varimax rotated factor matrix for the topsoil geochemical data from northwestern croatia (n= 293). 72 geologia croatica 54/1 darnley, a.g., björklund, a., bølviken, b. gustavsson, n., koval, p.v., plant, j.a., steenfelt, a., tauchid, m., xie, x., garret, r.g. & hall, g.e.m. (1995): a global geochemical database for environmental and resource management. final report of igcp project 295.unesco publishing, paris, 122 p. davis, j.c. (1986): statistics and data analysis in geology.john wiley & sons, new york, 646 p. de vivo, b., boni, m., marcello, a., di bonito, m. & russo, a. (1997): baseline geochemical mapping of sardinia (italy).j. geochem. explor., 60, 77-90. de vivo, b., boni, m., & costabile, s. (1998): formational anomalies versus mining pollution: geochemical risk maps of sardinia: italy.j. geochem. explor., 64, 321-337. de vivo, b., sava, a., villani, v. & messina, a. (1998a): cartografia geochimica dei monti peloritani (sicilia).mem. descr. carta geol. d’it., lv, 33-47. dolenec, t., faganeli, j. & pirc, s. (1998): major, minor and trace elements in surficial sediments from the open adriatic sea: a regional geochemical study.geol. croatica, 51/1, 59-73. durn, g. (1996): podrijetlo, sastav i uvjeti nastanka terra rossa istre (the origin, composition and genesis of istrian terra rossa soils).unpublished ph.d. thesis (in croatian), university of zagreb, 204 p. durn, g., ottner, f. & slovenec, d. (1999): mineralogical and geochemical indicators of the polygenetic nature of terra rossa in istria, croatia.geoderma, 91, 125150. ebens, r.j. & connor, j.j. (1980): geochemistry of loess and carbonate residium.usgs professional paper, 954g, 32p. golchert, b., landsberger, s. & hopke, p.k. (1991): determination of heavy metals in the rock river (illinois) through the analysis of sediments.jour. radioanal. nucl. chemistry art., 148/2, 319-337. förstner, u. & wittmann, g.t.w. (1981): metal pollution in the aquatic environment.springer-verlag, berlin, heidelberg, new york, 486 p. halami∆, j. & galovi∆, l. (1999): the geochemical atlas of northwestern croatia.open file report (in croatian), institute of geology, 72/1992, 111 p., zagreb. halami∆, j., miko, s., peh, z. & galovi∆, l. (2000): guidelines for geochemical mapping of croatia.open file report (in croatian), institute of geology, 51/2000, 22p., zagreb. hassan, f.s.m. & ismail, s.s. (1993): use of geologically biased enrichment factors (ef) as indicators of natural air pollutants.j. radioanal. nucl. chem. art., 167/2, 237-246. herak, m. (1986): a new concept of geotectonics of the dinarides.acta geol., 16/1, 1-42, zagreb. herak, m., jami»i∆, d., ©imuni∆, a. & bukovac, j. (1990): the northern boundary of the dinarides.acta geol., 20/1, 5-27, zagreb. isaaks, e. & sirvastava, r. (1989): an introduction to applied geostatistics.oxford university press, new york, 561 p. li, y.-h. (1981): geochemical cycles of elements and human perturbation.geochim. cosmochim. acta, 45, 20732084. matschullat, j. & bozau, e. (1996): atmospheric element input in the eastern ore mountains.appl. geochem., 11, 149-154. mckenzie, r.m. (1989): manganese oxides and hydroxides.in: dixon, j.b. & weed, s.b (eds.): minerals in soil environments. soil sci. soc. of america, madison, wisconsin, 439-465. miko, s., durn, g., palinka©, a. l., mashyanov, n., namjesnik, k. & ilyin, y. (1992): distribution of mercury, and aerosols of lead and cadmium in the atmosphere of zagreb.rud. met. zbornik, 39/3-4, 369387, ljubljana. miko, s., durn, g. & prohi∆, e. (1999): evaluation of terra rossa geochemical baselines from croatian karst regions.j. geochem. explor., 66, 173-182. m i k o, s., peh, z., bukovec, d., p r o h i ∆ , e. & k a s tmüller, æ. ( 2 0 0 0 ) : geochemical baseline mapping and lead pollution assessment of soils on karst in western croatia.natura croatica, 9, 1, 41-59, zagreb. miko, s., peh, z. & ©parica, ma. (2001): the geochemical atlas of western croatia.open file report (in croatian), institute of geology, 36/2001, 28 p., zagreb. mlakar, i. (1993): on the problems of the litija ore field.geologija, 36, 249-338, ljubljana. namjesnik, k., palinka©, a. l., miko, s., durn, g., poli∆, d. & kvrgnja©, l. (1992): lead, zinc, nickel and mercury in soil along road sides and of some rural and urban parts of zagreb, croatia.rud. met. zbornik, 39, 1-2, 93-112, ljubljana. narodne novine (1992): the protocol for the protection of agricultural lands from pollution by potentially toxic substances.ministry of agriculture, forestry and water resources (in croatian), 15/333, 274-276, zagreb. palinka©, a. l., namjesnik, k., miko, s., durn, g. & pirc. s. (1996): distribution of mercury, lead and cadmium in zagreb city soils.in: richardson, m. (ed.): environmental xenobiotics. taylor & francis, london, 355-374. peh, z. & miko, s. (1999): the geochemical atlas of middle and southern dalmatia.open file report (in croatian), institute of geology, 115/1999, 102 p., zagreb. pirc, s., mcneal, m.j., lenar»i», t., prohi∆, e. & svrkota, r. (1991): geochemical mapping of carbonate terrain.bull. inst. mettal. min., applied earth sci., 100, b-74-b-83. prohi∆, e., hausberger, g. & davis, j.c. (1997): geochemical patterns in soils of the karst region, croatia.j. geochem. explor., 60, 127-138. prohi∆, e., miko, s. & peh, z. (1995): normalization and trace element contamination of soils in a karstic polje an example from the sinjsko polje, croatia.geol. croatica, 48/1, 67-86. prohi∆, e., peh, z. & miko, s. (1998): geochemical characterization of a karst polje an example from sinjsko polje, croatia.environmental geology, 33/4, 263-273. 73miko, halamiê, peh & galoviê: geochemical baseline mapping of soils... reimann, c. (1988): comparison of stream sediment and soil sampling for regional exploration in the eastern alps, austria.j. geochem. explor., 31, 75-85. salminen, r. & tarvainen, t. (1997): the problem of defining geochemical baselines. a case study of selected elements and geological materials in finland.j. geochem. explor., 60, 91-98. salminen, r., tarvainen, t., demetriades, a., duris, m., fordyce, f.m., regorauskiene, v., kahelin, h., kivisilla, j., klaver, g., klein, h., larson, j.o., lis, j., locutura, j., marsina, k., mjartanova, h., mouvet, c., o ′connor, p., odor, l., ottonello, g., paukola, t., plant, j.a., reimann, c., schermann, o., siewers, u., steenfelt, a., van der sluys, j., de vivo, b. & williams, l. (1998): foregs geochemical mapping field manual.geological survey of finland, 36 p., espoo. schwertman, u. & taylor, r.m. (1989): iron oxides.in: dixon, j.b. & weed, s.b (eds.): minerals in soil environments. soil sci. soc. of america, madison, wisconsin, 379-438. ©ajn, r., bidovec, m., andjelov, m., pirc, s. & gosar, m. (1998): geochemical atlas of ljubljana and environs.inπtitut za geologiju, geotehniko in geofiziko, ljubljana, 34p. ©kori∆, a. (1986): postanak, razvoj i sistematika tla (genesis, development, and systematics of soils).fakultet poljopriv. znan. sveuë. u zagrebu (in croatian), 172 p., zagreb. ©poljar, a. (1999): fao klasifikacija s bazom podataka za pedoloπku kartu republike hrvatske sitnog mjerila (fao classification with database of pedologic map of croatia in small scale).unpubl. m.sc. thesis (in croatian, university of zagreb, 75 p. van lienen, f., frapporti, g. & stein, a. (2000): construction of maps for soil recycling in regional infrastructural works integrating soil-quality laws.geologie en mijnbouw/netherlands journal of geosciences, 79/4, 449-457. veli∆, i. & veli∆, j. (1993): geoloπka karta republike hrvatske (geological map of croatia).in: berti∆, i. (ed.): zemljopisni atlas republike hrvatske. ©kolska knjiga, leksikografski zavod m. krleæa, zagreb. windom, h., schropp, s., calder, f., ryan, j., smith, r.j.r., burney, l., lewis, f. & rawilson, c. (1989): natural trace metal concentrations in estuarine and coastal marine sediments of the south-eastern u.s.environ. sci. technol., 23/3, 314-320. manuscript received november 29, 2000. revised manuscript accepted april 23, 2001. 74 geologia croatica 54/1 plate 1 the distribution of al in soils from s dalmatia. plate 1 75miko, halamiê, peh & galoviê plate 2 the distribution of al in soils from nw croatia. plate 2 76 geologia croatica 54/1 plate 3 the distribution of as in soils from s dalmatia. plate 3 77miko, halamiê, peh & galoviê plate 4 the distribution of as in soils from nw croatia. plate 4 78 geologia croatica 54/1 plate 5 the distribution of ba in soils from s dalmatia. plate 5 79miko, halamiê, peh & galoviê plate 6 the distribution of ba in soils from nw croatia. plate 6 80 geologia croatica 54/1 plate 7 the distribution of ca in soils from s dalmatia. plate 7 81miko, halamiê, peh & galoviê plate 8 the distribution of ca in soils from nw croatia. plate 8 82 geologia croatica 54/1 plate 9 the distribution of co in soils from s dalmatia. plate 9 83miko, halamiê, peh & galoviê plate 10 the distribution of co in soils from nw croatia. plate 10 84 geologia croatica 54/1 plate 11 the distribution of cr in soils from s dalmatia. plate 11 85miko, halamiê, peh & galoviê plate 12 the distribution of cr in soils from nw croatia. plate 12 86 geologia croatica 54/1 plate 13 the distribution of cu in soils from s dalmatia. plate 13 87miko, halamiê, peh & galoviê plate 14 the distribution of cu in soils from nw croatia. plate 14 88 geologia croatica 54/1 plate 15 the distribution of fe in soils from s dalmatia. plate 15 89miko, halamiê, peh & galoviê plate 16 the distribution of fe in soils from nw croatia. plate 16 90 geologia croatica 54/1 plate 17 the distribution of la in soils from s dalmatia. plate 17 91miko, halamiê, peh & galoviê plate 18 the distribution of la in soils from nw croatia. plate 18 92 geologia croatica 54/1 plate 19 the distribution of pb in soils from s dalmatia. plate 19 93miko, halamiê, peh & galoviê plate 20 the distribution of pb in soils from nw croatia. plate 20 94 geologia croatica 54/1 plate 21 the distribution of k in soils from s dalmatia. plate 21 95miko, halamiê, peh & galoviê plate 22 the distribution of k in soils from nw croatia. plate 22 96 geologia croatica 54/1 plate 23 the distribution of na in soils from s dalmatia. plate 23 97miko, halamiê, peh & galoviê plate 24 the distribution of na in soils from nw croatia. plate 24 98 geologia croatica 54/1 plate 25 the distribution of mg in soils from s dalmatia. plate 25 99miko, halamiê, peh & galoviê plate 26 the distribution of mg in soils from nw croatia. plate 26 100 geologia croatica 54/1 plate 27 the distribution of mn in soils from s dalmatia. plate 27 101miko, halamiê, peh & galoviê plate 28 the distribution of mn in soils from nw croatia. plate 28 102 geologia croatica 54/1 plate 29 the distribution of ni in soils from s dalmatia. plate 29 103miko, halamiê, peh & galoviê plate 30 the distribution of ni in soils from nw croatia. plate 30 104 geologia croatica 54/1 plate 31 the distribution of p in soils from s dalmatia. plate 31 105miko, halamiê, peh & galoviê plate 32 the distribution of p in soils from nw croatia. plate 32 106 geologia croatica 54/1 plate 33 the distribution of sc in soils from s dalmatia. plate 33 107miko, halamiê, peh & galoviê plate 34 the distribution of sc in soils from nw croatia. plate 34 108 geologia croatica 54/1 plate 35 the distribution of sr in soils from s dalmatia. plate 35 109miko, halamiê, peh & galoviê plate 36 the distribution of sr in soils from nw croatia. plate 36 110 geologia croatica 54/1 plate 37 the distribution of ti in soils from s dalmatia. plate 37 111miko, halamiê, peh & galoviê plate 38 the distribution of ti in soils from nw croatia. plate 38 112 geologia croatica 54/1 plate 39 the distribution of th in soils from s dalmatia. plate 39 113miko, halamiê, peh & galoviê plate 40 the distribution of th in soils from nw croatia. plate 40 114 geologia croatica 54/1 plate 41 the distribution of v in soils from s dalmatia. plate 41 115miko, halamiê, peh & galoviê plate 42 the distribution of v in soils from nw croatia. plate 42 116 geologia croatica 54/1 plate 43 the distribution of zn in soils from s dalmatia. plate 43 117miko, halamiê, peh & galoviê plate 44 the distribution of zn in soils from nw croatia. plate 44 118 geologia croatica 54/1 plate 45 the distribution of hg in soils from nw croatia. plate 45 zaineldeen.indd 55 �ab stra ct coastal plain deposits of the gaza strip have been distinguished in the gaza formation (pleistocene) of the kurkar group. the kurkar layers (medium to coarse-grained calcareous sandstone) are characterized by abundant crossbedding that has two sets of cross-beds. these kurkar layers form the ridges along the mediterranean coast. the dip, and dip direction of the cross-beds, were measured at fi ve sites to determine the palaeowind direction. the palaeowind directions were measured for the fi rst time in the study area. the kurkar layers are interpreted as having been deposited in an aeolian environment. results at sheikh ejlin ridge show that the lower set is dipping eastward (19/099), while the upper set dips northeast (23/051). at the al montar ridge however, the lower set dips southeast (18/146), while the upper set dips north (19/001). these ridges are not coeval, but the precise age relationship between them is as yet unknown. however, the results indicate that there was a change in the palaeowind direction during deposition of the kurkar layers, from westerly to southwesterly at the sheikh ejlin ridge and from northwesterly to southerly at al montar ridge. keywords: gaza, kurkar, aeolian deposits, cross-bedding, palaeowind, sheikh ejlin, al montar, quaternary palaeowind estimation of cross-bedding within the aeolian kurkar layers of the gaza formation, gaza strip, palestine � usama f. zaineldeen department of geology, al azhar university – gaza, p.o. box 1277, gaza, palestine; (u.zain@alazhar-gaza.edu) doi: 104154/gc.2010.03 geologia croatica 63/1 55–65 11 figs. 2 tabs. zagreb 2010 geologia croaticageologia croatica 1. introduction the gaza strip is located on the southeastern coastal plain of the mediterranean sea (fig. 1). the coastal zone of the gaza strip is 42 km long, and varies between 6 and 12 km wide, covering an area of 365 km2. it is overlain by pleistocene–holocene sediments that have alternating stratifi ed calcareous sandstone (locally named as kurkar) and red brown layers (locally named as hamra). the coastline of the gaza strip forms only a small section of a larger concave system that extends from alexandria at the west side of the nile delta, via port said, the bardawil lagoon, el arish, gaza, up to the bay of haifa (inman & jenkins, 1984). the topography of the coastal plain is determined by the exposure of two aeolian kurkar ridges presumably of different ages (sivan & porat, 2004). the ridges are separated by a deep depression (20–40m above sea level) containing alluvial deposits. these ridges have been studied by several authors. picard (1943) noted that the kurkar is mainly distributed in the western half of the coastal plain and forms ridges parallel to the coast. neev et al. (1987) recorded three onshore kurkar ridges along coastal line, while gaza environmental profile (gep, 1994) mapped fi ve scattered ridges on the gaza strip. anan & zaineldeen (2008) mapped just two ridges within the gaza strip running geologia croatica 63/1geologia croatica 56 the exposures at the two ridges, are composed of alternating of kurkar and hamra layers, in the gaza formation of the kurkar group (fig. 2). the kurkar group describes coastal sediments from the pliocene through to the recent periods. these kurkar ridges extend further to the north, parallel to the mediterranean coast as observed by yaalon & dan (1967). the sands of the kurkar layers are wind blown deposits originating from the nile delta (horowitz, 1979). since the beginning of the pleistocene sediments transported into the mediterranean sea by the nile river, have been spread along the sinai and palestinian coasts by longshore currents (pomerancblum, 1966; goldsmith & golik, 1980; coleman et al., 1981; inman & jenkins, 1984; rohrlich & goldsmith, 1984; carmel et al., 1985; stanley, 1989; frihy et al., 1991; frihy & lotfy, 1997; perlin & kit, 1999; zviely et al., 2006; zviely et al, 2007; anan & zaineldeen, 2008). fi gu re 1: a simplifi ed map of the gaza strip showing the distribution of sites within the study area (after anan & zaineldeen, 2008). fi gu re 2: kurkar and hamra layers at site gs01 (hammer scale is 32 cm long). ne–sw, parallel to the mediterranean coastline. they named the two ridges as: sheikh ejlin ridge, which extends up to the current coastline in the west, and the al montar ridge running near the armistice line in the east. hassan et al. (1986) recorded a series of eight limestone ridges that run parallel to the coast, west of alexandria, egypt. stanley (2005) also traced eight kurkar ridges to the west of alexandria. the aim of the present work was to 1) study the crossbedding within the kurkar layers at the two ridges in order to determine the type of cross beds occurring at each ridge, 2) measure the dip and dip direction of the cross beds to estimate the palaeowind direction during deposition, and 3) compare the palaeowind directions of the two ridges with each other to give a better view of the circumstances during their respective formation. 2. object of study the study area is located within the gaza strip of palestine. five sites (gs01, gs02, gs03, gs04 and gs05), as shown in fig. 1, were examined over many fi eld campaigns. sites were located on the best exposures of the kurkar layers in the gaza strip. three of these sites (gs01, gs02 and gs03) are located on the sheikh ejlin ridge, and the other two (gs04 and gs05) are on the al montar ridge. the coordinates of these fi ve sites are shown table 1. all observation sites were located using a portable gps. table 1: coordinates of the observation sites. site location coordinates ridge gs01 deir elbalah 31° 25.07’ n, 34° 19.75’ e sheik ejlings02 south sheikh ejlin 31° 27.47’ n, 34° 22.19’ e gs03 annawras 31° 33.48’ n, 34° 24.80’ e gs04 tal errayyes 31° 30.78’ n, 34° 29.52’ e al montargs05 tal elkashef (tal zommo) 31° 31.35’ n, 34° 30.09’ e usama f. zaineldeen: palaeowind estimation of cross-bedding within the aeolian kurkar layers of the gaza formation, gaza strip, palestine geologia croatica 57 rodrigez-lopez et al. (2008) carried out a study of the aeolian sand at the mid-cretaceous western tethyan margin, iberian basin, spain. they noted that sub-tropical climbing translatent strata, grain fl ow and soft sediment deformation are among some of the small scale structures and components observed in the aeolian dune sandstones. kocurek (1981) showed that surfaces and other manifestations of microtopography common in ancient aeolian strata are interpreted as representing damp or cemented surfaces. 4. description of the exposures the outcrops consist of alternating kurkar and hamra layers of pleistocene age, (the gaza formation of the kurkar group). at each location, cross-bedding was recognized within the kurkar layers (fig. 3). the cross-bedded sediments were distinguished in the fi eld by layers of foresets, (the series of layers that form on the lee side of the bed form). they are also recognized by truncations in sets of foresets. two sets of cross-bedding have been identifi ed within the kurkar layer at the fi ve sites. kurkar layers in the study area consist of coarseto medium-grained sandstone cemented by calcium carbonate 3. palaeowind and palaeowind indicators palaeowind indicators are oriented sedimentary structures interpreted to have been deposited by grain fl ow. grain fl ow strata are slightly coarser than grain fall sands that occupy the upper middle, and upper parts of aeolian slipface dunes (hunter, 1977). cross-bed slip faces are one of the palaeowind indicators, and can be used to determine the direction of the wind that actually deposited the sediments. this corresponds to the mean value of the down-dip direction shown by the foreset beds (pettijohn, 1975; kocurek, 1981). palaeowind indicator analysis is important because it provides direct information about the orientation of the sedimentary system. in the current study, cross beds have been used to estimate the palaeowind direction of the current that deposited the sandstones. several studies in aeolian processes have been seen in published papers (e.g. yaalon & laronne 1971; kocurek, 1981, 1991). studies dealing with sand dunes have also been published (e.g. yaalon & dan, 1967; hunter, 1977; kocurek, 1981; clemmensen & abrahamsen 1983; greely & iversen, 1985; pye, 1987; mountney & thompson, 2002; rodrigez-lopez et al., 2008). fi gu re 3: lower and upper sets of cross-beds within the kurkar layer. a) at deir elbalah, (gs01), b) at south sheikh ejlin (gs02), c) at annawras (gs03), d) at tal errayyes (gs04). hammer scale is 32 cm long. a b c d geologia croatica 63/1geologia croatica 58 (about 30%). most of the kurkar layers are cross-bedded, laminated and massive sandstone. tabular types of crossbedding have been observed in the study area. gvirtzman et al. (1984, 1998) pointed out that kurkar and hamra sequences are very similar along the coastal plain. the sand dunes occur along the shoreline especially near deir elbalah, and vary in thickness up to 15 m. the dunes are oriented east-northeast to west-southwest. further to the north, the dunes become irregular and the sand accumulations are scattered in a 2 to 3 km zone along the coast (gaza environmental profile, 1994). aeolian deposits are dominant in the gaza strip. those deposited especially in the southern gaza strip, have more loess and are mixed with windblown sands, but are much thinner. fi gu re 4: rose diagram and stereographic projection for the cross-beds at the deir elbalah site (gs01). column (a) for the lower set and (b) for the upper one. a: lower set b: upper set usama f. zaineldeen: palaeowind estimation of cross-bedding within the aeolian kurkar layers of the gaza formation, gaza strip, palestine geologia croatica 59 the sand forms the bulk of the coastal sediments, together with additional calcareous materials and aeolian and alluvial silty and clayey materials. the sand is composed of well sorted medium to coarse quartz grains, with less than 5% of feldspar and heavy minerals. the sand supply was reduced northwards and less but fi ner grained sandy material deposited along the coast to haifa (gaza environmental profile, 1994). the mineralogy of the aeolianites in the northern part of the coastal plain is dominated by quartz and a little feldspar (yaalon & laronne, 1971). frechen et al. (2002) pointed out that neither the kurkar nor hamra layers correlate with glacial and interglacial periods of the northern hemisphere. sivan & porat (2004) showed that the kurkar accumulated along the coastal plain at different time intervals throughout the late pleistocene, and that its deposition was figure 5: rose diagram and stereographic projection for cross-beds at the south sheik ejlin site (gs02). columns a and b are same as for figure 4. a: lower set b: upper set geologia croatica 63/1geologia croatica 60 not necessarily associated with high sea levels. they obtained detailed stratigraphy and luminescence ages for the kurkar and hamra layers that range from 35 to 101 ka, indicating coeval formation of these units during the late pleistocene. at location gs01, at deir elbalah, a kurkar layer overlies the hamra layer. tabular cross-bedding has been observed within the kurkar layers at this site. two sets of cross-beds have been recognized (fig. 3a). the lower set dips east, while the upper set is dips northeast. 70 measurements of dip and dip direction for the cross-beds of the lower and upper sets have been measured. the measurements plotted as rose diagram and as a stereographic projection (fig. 4). the mean dip and dip direction have been calculated for the lower set as 16/098 (to the east) while it is 23/053 (to the northeast) for the upper set. figure 6: rose diagram and stereographic projection for the cross-beds at the annawras site (gs03). columns a and b as figure 4. a: lower set b: upper set usama f. zaineldeen: palaeowind estimation of cross-bedding within the aeolian kurkar layers of the gaza formation, gaza strip, palestine geologia croatica 61 at site gs02, south sheikh ejlin, the kurkar layer also shows tabular cross-bedding (fig. 3b) and overlies the hamra layer. fig. 5 shows the represented data collected at this location site. the mean dip and dip direction for the lower set of cross-beds is 20/096 (to the east) and for the upper set is 20/042 (to the north east). these mean values have been calculated from 41 measurements collected at this site. at site gs03, at annawras, to the north of the gaza strip, only the kurkar layer has been observed (fig. 3c) and shows tabular cross-bedding with two sets of cross-beds. 69 measurements of dip and dip direction were collected for the two sets of cross-beds (fig. 6). the mean dip and dip direction for the lower set is 20/104 (to the east) and for the upper set is 27/055 (to the northeast). convolute cross-bedding, as observed here (fig. 7a), is a distinctive kind of internal deformation seen within many sandy beds that have been laid down very rapidly. it takes an irregular form within the bed itself, which is otherwise not affected by the deformation. although its origin is somewhat uncertain, it appears to affect sediments in a state of partial liquefaction caused by its very rapid deposition, so that this structure is most likely to be formed by the upwards escape of water during the very early stages of compaction (roberts, 1996). the three previous sites (gs01, gs02 and gs03) are located at sheikh ejlin ridge where the lower set of crossbeds dips east and the upper one dips northeast. at site gs04, tal errayyes, two kurkar layers, with hamra layer in between, have been observed. tal errayyes is located at the al montar ridge where the dip directions of the two sets of the cross-beds are differ from those at the previous locations on the sheikh ejlin ridge. within each of kurkar layer at this site (gs04), two sets of tabular crossbedding have been identifi ed (fig. 3d). the lower set dips southeast while the upper one dips north. fig 8 shows the results of 61 dip and dip direction measurements for the cross-beds, collected for the lower and upper sets within the two of kurkar layers. the mean dip and dip direction for the lower set is 18/146 (to the southeast) and 21/359 (to the north) for the upper one. convolute cross-bedding was again observed at tal errayyes (fig. 7b). at site gs05, tal elkashef (tal zommo), a kurkar layer with only one set of cross bedding was observed. the set dips north here (fig. 9). since sites gs04 and gs05 are located on the al montar ridge, the set of cross-beds within the kurkar layer observed at gs05, is the upper set of tabular cross-bedding that occur on the al montar ridge. the mean dip and dip direction for this set is 18/003 (to the north). 5. discussion the current study presents palaeowind directions obtained from the cross-bedding data from within the aeolian kurkar layers of the gaza strip, palestine. wind has much less competence than water to pick up particles. the aeolian environment is characterized by spectacular cross-beds at high angles of 20–30 degrees. most of these beds are tabular (planar), as shown in the kurkar layers in the study area. moreover, sediments deposited by water are more consistent than those deposited by the wind. the kurkar of the gaza strip is less consistent. therefore, the kurkar of the study area is interpreted as having been deposited in an aeolian environment. kurkar layers are soft and reliable. yaalon (1967) proposed that the main factors controlling the transformation of the calcareous dune sand into either a consolidated aeolianite or a hamra layer are the original content of caco3 in the dune and the intensity of leaching as affected by the relief and micro-climatic conditions. he concluded that all the sedimentary deposits and associated soils could have formed under similar climatic conditions. picard (1943) noted that kurkar is defi ned as calcareous sandstone derived from littoral as well as coastal dunesand and later diagenetically hardened by calcareous solutions. neev et al. (1987) noted that the kurkar seems to have been deposited in a continental environment from aeolian sands that accumulated during both high stands and regressions of sea level. increased sand is related to increased figure 7: convolute cross-bedding observed within the kurkar layers. a) at annawras, b) at tal errayyes. hammer and pencil scale are 32 and 14 cm respectively. a b geologia croatica 63/1geologia croatica 62 tectonic activity that caused the uplift and disturbance of sediments within the nile delta province, thereby leading to increased erosion. the sand ingression across the coastline is superimposed on the tectonic destruction. at the central coastal plain, to the north of the study area, frechen et al. (2002) and porat et al. (2004) noted that the kurkar ridges at the levant are designated to represent typical longitudinal sand dunes formed synchronously parallel to the coastline by a dominant wind direction perpendicular to the coast. the different facies are related to changes in the environmental setting. they dated these sediments by luminescence methods as 65 ka to 5 ka. careful study of cross beds can often determine ancient wind directions as the dip direction of the cross-bedded sediments provides insight into wind direction. the fi eld observations show that there are two sets of cross-beds within the figure 8: rose diagram and stereographic projection for the cross-beds at the tal errayyes site (gs04). columns a and b as for figure 4. a: lower set b: upper set usama f. zaineldeen: palaeowind estimation of cross-bedding within the aeolian kurkar layers of the gaza formation, gaza strip, palestine geologia croatica 63 kurkar layers in the study area. as sites gs01, gs02 and gs03 are located on the same, sheikh ejlin ridge, the mean values for dip and dip direction for each set were calculated for the three observation sites. the result shows that the mean dip and dip direction of the lower set at sheikh ejlin ridge is 19/099 (to the east) while it is 23/051 (to the northeast) for the upper one (table 2 and fig. 10). since the dip direction of the cross-bedded sediments provides insight into wind direction, the palaeowind direction at the sheikh ejlin ridge was westerly and southwesterly during deposition of the kurkar layers. the same direction was obtained by yaalon & laronne (1971) at the aeolianite coastal ridge a few tens of kilometres north of the study area. they indicated that a westerly and southwesterly wind regime prevailed in the past. this ridge is the extension of sheikh ejlin ridge of the study area. figure 9: rose diagram and stereographic projection for the upper set of cross-beds at the tal elkashef site (gs05). a: sheikh ejlin ridge b: al montar ridge figure 10: rose of palaeowind directions of all data for both sets at the two ridges of gaza strip. geologia croatica 63/1geologia croatica 64 as sites gs04 and gs05 are located on the al montar ridge, the mean values of the dip and dip direction of the two sets were calculated for the two observation sites. since this ridge is presumably not age equivalent with sheikh ejlin, it is not surprising that the dip and dip directions are different. the mean dip and dip direction of the lower set of the cross-beds at gs04 site (the lower set observed just in this site) is 18/146 (to southeast). for the upper sets, the mean dip and dip direction at the two locations is 19/001 (to the north) as shown in table 2 and fig. 10. it can be inferred that the palaeowind direction was northwesterly and southerly at al montar ridge. the mean direction of the palaeowind at each site was plotted at a map as shown in fig. 11. the results show that the direction of the palaeowind was westerly for the bottom (lower set) of the kurkar layer and southwesterly for the upper set of the layer at sheikh ejlin ridge, while it was northwesterly at the bottom of the layer and southerly at the top of it at al montar ridge. this result was clear for all fi ve sites within the study area, suggesting that there was a change in wind direction during deposition of the kurkar layers from a westerly to southwesterly direction at sheikh ejlin ridge, and from a northwesterly to southerly direction at the al montar ridge. 6. conclusion the study shows that the kurkar layers are characterized by their tabular (planar) and convolute cross-bedding. two sets of cross-beds observed within the kurkar layers are documented. the dip direction of these sets indicates the direction of wind during deposition of the kurkar layers. the lower set dips east at the sheikh ejlin ridge and southeast at the al montar ridge, while the upper set dips northeast at sheikh ejlin ridge and north at the al montar ridge. it can be concluded that a change of palaeowind direction occurred during deposition of the kurkar layers in the gaza strip in both analysed ridges. this appears to have been a change from a westerly to southwesterly wind at sheikh ejlin ridge, as already reported by yaalon & laronne (1971), and from a northwesterly to southerly wind at the al montar ridge. references anan, h.s. & zaineldeen, u. (2008): kurkar ridges in the gaza strip of palestine.– m.e.r.c. ain shams university, earth science series, 22, 139–146. carmel, z., inman, d. & golik, a. (1985): directional wave measurements at haifa, israel, and sediment transport along the nile littoral cell.– coast. eng., 9, 21–36. table 2: summary of the mean dip and dip direction of the cross-beds within the kurkar layer of the study area. site lat. long. location lower set upper set sheikh ejlin ridge: gs01 31° 25.07’ 34° 19.75’ deir elbalah 16/098 23/053 gs02 31° 27.47’ 34° 22.19’ south sheikh ejlin 20/096 20/042 gs03 31° 33.48’ 34° 24.80’ annawras 20/104 27/055 mean 19/099 23/051 al montar ridge: gs04 31° 30.78’ 34° 29.52’ tal errayyes 18/146 21/359 gs05 31° 31.35’ 34° 30.09’ tal elkashef – 18/003 mean 18/146 19/001 fi gu re 11: rose of palaeowind directions at each site within the study area. usama f. zaineldeen: palaeowind estimation of cross-bedding within the aeolian kurkar layers of the gaza formation, gaza strip, palestine geologia croatica 65 clemmensen, l.b. & abrahamsen, k. (1983): aeolian stratifi cation and facies association in desert sediments, arran basin, (permian), scotland.– sedimentology, 30, 311–339. coleman, j.m., roberts, h.h., murray, s.p. & salama, m. (1981): morphology and dynamic sedimentology of the eastern nile delta shelf.– mar. geol., 42, 301–326. frechen, m., neber, a., dermann, b., tsatskin, a., boenigk, w. & ronen, a. (2002): chronostratigraphy of aeolianites from the sharon coastal plain of israel.– quat. inter., 89, 31– 44. frihy, o.e. & lotfy, m.f. (1997): shoreline changes and beach-sand sorting along the northern sinai coast of egypt.– geo. mar. lett., 17, 140–146. frihy, o.e., fanos, a.m., khafagy, a.a. & komar, p.d. (1991): patterns of sediment transport along the nile delta, egypt.– coast. eng., 15, 409–429. gaza environmental profile (gep) (1994): gaza environmental profi le, part one, inventory of resources, prepared for the palestinian environmental protection authority by euroconsult and iwac, 6 p. goldsmith, v. & golik, a. (1980): sediment transport model of the southeastern mediterranean coast.– mar. geol., 37, 135–147. greeley, r. & iversen, j.d. (1985): wind as a geological process. cambridge planetary science series 4, cambridge university press, cambridge, 333 p. gvirtzman, g., shachnai, e., bakler, n. & ilani, s. (1984): stratigraphy of the kurkar group (quaternary) of the coastal plain of israel. geological survey israel, current research, 1983–84, 70–82. gvirtzman, g., netser, m. & katsav, e. (1998): last-glacial to holocene kurkar ridges, hamra soils and dune fi elds in the coastal belt of israel.– israeli journal of earth science, 47, 29–46. hassan, f.a., hegab, o. & el-shahat, a. (1986): mediterranean littoral cycles, west alexandria, egypt and implications for archeological exploration.– nyame akuma, 27, 3–5. horowitz, a. (1979): the quaternary of israel. academic press, new york, 85 p. hunter, r.e., 1977. basic types of stratifi cation in small eolian dunes.– sedimentology, 24, 361–387. inman, d.l. & jenkins, s.a. (1984): the nile littoral cell and man’s impact on the coastal zone of the southeastern mediterranean.– in: proceedings 19th coastal engineering conference. american society of civil engineers, 2, 1600–1617. kocurek, g. (1981): signifi cance of interdune deposits and bounding surfaces in aeolian dune sands.– sedimentology, 28, 753–780. kocurek, g. (1991): interpretation of ancient eolian sand dunes.– annual reviews of earth and planetary science, 19, 43–75. mountney, n.p. & thompson, d.b. (2002): stratigraphic evolution and preservation of aeolian dune and damp/wet interdune strata: an example from the triassic helsby sandstone formation, cheshire basin, uk.– sedimentology, 49, 805–833. neev, d., bakier, n. & emery, k.o. (1987): mediterranean coast of israel and sinai, holocene tectonism from geology, geophysics and archeology. taylor and francis publ., 130 p. perlin, a. & kit, e. (1999): longshore sediment transport on the mediterranean coast of israel. j. waterw. port coast.– ocean eng., 125/2, 80–87. pettijon, f.j. (1975): sedimentary rocks. third edition. harper and row publishers, 628 p. picard, l. (1943): structure and evolution of palestine.– bulletin of the geology department, hebrew university, jerusalem, 4/2–4, 134 p. pomerancblum, m. (1966): the distribution of heavy minerals and their hydraulic equivalents in sediments of the mediterranean shelf of israel.– j. sediment. petrol., 36/1, 162–174. porat, n., wintle, a.g. & ritte, m. (2004): mode and timing of kurkar and hamra formation, central coastal plain, israel.– israel journal of earth-sciences, 53, 13– 25. pye, k. (1987): aeolian dust and dust deposits. academic press, london, 334 p. roberts, j.l. (1996): the macmillan field guide to geological structures. macmillan publishers limited, london, 250 p. rodrigez-lopez, j.p., melendez, n., de boer, p.l. & soria, a.r. (2008): aeolian sand sea development along the mid-cretaceous western tethyan margin (spain): erg sedimentology and palaeoclimate implication.– sedimentology, 55, 1253–1292. rohrlich, v. & golsmith, v. (1984): sediment transport along the southeast mediterranean: a geological perspective.– geo mar. lett., 4, 99–103. sivan, d. & porat, n. (2004): evidence from luminescence for late pleistocene formation of calcareous aeolianite (kurkar) and paleosol (hamra) in the carmel coast, israel.– palaeogeography, palaeoclimatology, palaeoecology, 211, 95–106. stanley, d.j. (1989): sediment transport on the coast and shelf between the nile delta and israeli margin as determined by heavy minerals.– j. coast. res., 5/4, 813–828. stanley, d. j. (2005): growth faults, a distinct carbonate-siliciclastic interface and recent coastal evolution, nw delta, egypt.– journal of coastal research, 42, 309–318. yaalon, d.h. (1967): factors affecting the lithifi cation of eolianite and interpretation of its environmental signifi cance in the coastal plain of israel.– journal of sedimentary petrology, 37, 1189–1199. yaalon, d.h. & dan, j. (1967): factors controlling soil formation and distribution in the mediterranean coastal plain of israel during the quaternary.– quaternary soils, seventh nqua congress 1965, 321–338. yaalon, d.h. & laronne j. (1971): internal structures in eolianites and palaeowinds, mediterranean coast, israel.– journal of sedimentary petrology, 41, 1059–1064. zviely, d., sivan, d., ecker, a., bakler, n., rohrlich, v., galili, e., boaretto, e., klein, m. & kit, e. (2006): the holocene evolution of haifa bay area, israel, and its infl uence on the ancient human settlements.– the holocene, 16/6, 849–861. zviely, d., kit, e. & klein, m. (2007): longshore sand transport estimates along the mediterranean coast of israel in the holocene.– mar. geol., 238, 61–73. manuscript received april 25, 2009 revised manuscript accepted january 28, 2010 available online february 28, 2010 i geol. croat. soil 27 32 4 figs. 1 tab. zagreb 1997 strontium dependence of the lattice constants of barites from the kresevo area in central bosnia (bosnia and herzegovina) dragutin slovenec', dubravko siftar " milko ,jaksic2 and ivan ,jurkovic' key words: strontiulll bearing barites, latlice con­ stants, inhomogeneous st rontium distribution in barite, xrd determination of sf in barite, kresevo, central bosn ia. abstract the jan ice constants of a sy nthetic bas04 and fourtee n natural b'lri[c samples from lhe kresevo area (centra! bosnia) were deter­ mined by x-ray powder diffraction. the natural samp les contained from 0.3[7 .6 mole % 51"s04' and negligible concentrations of ca and pb «0.03 and 0 .02 wt. %, res pec tiv ely ), thu s rep resen ting almost pure (l3a,sr)s04 solid so lut ions. the diffraoion lines of moslnaturaj samp les were broadened in rc!~l1ion 10 those of synthetic i3as04 • thi s results from obvious com­ positional heterogeneity, e.g. the heterogeneous distribution of stron­ tium, as is clcarly observed from sr variation pal(erns across a surface of the barite obtained by proton microprobe analysis . nevertheless, the present values of unit-cell parameters arc in agreemen! with those of synthetic (13a ,s r)so_1 so lid solu tion s documented ill the literature. it has been proven ihal the int erplanar spacing drol may be used for dete rm ination o f thc sr co nt cn t of natural barites; the absolute error v;li·ies from ±o.3 mole % srs04 (for homogcncous samples hav­ ing th e difrracti0l11ine 004 clearly resolved in spcctral doublet com­ ponc nts) up \0 ±o.5 llloic % srs04 (for the samples with compositio­ nal hcterogeneity having a broadened and rciative poorly defined dif­ fraction linc cxl4) . 1. introduction experiment al studies of the system bas04 srs04 showed that a comp lete series of solid solution exis ts between the orthorombi e rorms of bas04 and srs04 , i. e. between barite and celest ite (e.g. bostrom et a1. , 1967). however, the natural intermediary members between 10 and 90 mole % srs04 are very rarely obser­ ved. hydrothermal barites from the kresevo area in cen­ tral bosnia contain from 0.1 17 .6 mole % srs04 (i.e. from 0.1 to 14.4 wi. % srs04) as reported by sift ar (1988) who chemically analysed 33 samples. the wide i racllily of mining, geology and petrol eum engineeri ng, university of zagreb, pi crottijeva 6, hr-l0cxlo zagreb, croatia. 2 ruder 13oskovic in stitut e, 13ijenicka ces ta 54. hri 0000 zagreb, croatia. sr concentration range, as well as a relatively large number of available samples provided an excellent opportunity to examine how the unit ce ll parameters depend on sr content in natural barites. for the purpose of the present examination 14 barite samples were used (7 samples analysed in sift ar, 1988, and 7 new sam­ ples, also analyzed by siftar in this study). in addi­ tion , the unit-cell parameters of a synthetic bas04 were determined which was prepared by sedimentation from analytically pure chemicals (h2s04 and bacl,h20 , with less than 0.05 wt. % sr). synthetic bas04 was heated at 900°c for 3 hours in order to obtain larger crystallites. the treated sample did not show any mea­ surable broadening of x-ray diffraction lines due to the small crystallite size. in this paper the presen t data as we ll as the cited data of lattice constants and the miller indices are prc­ sented on the basis or the space group pnma (62). 2. basic geological data the barite bearing krescvo region is a part of the central bosnian are mountains. it is an area about 22 km long and 2-4 km wide. the oldest rocks are pre­ devonian metamorphic rocks which grade into metasandstones (jovanovic ct ai., 1977). devonian rossiliferous layered or bedded dolomites, limestones or marbles overlie this metamorphic complex. magmatic rocks are rcprcsented by upper palaeozoic rhyolites and melarhyolites which either form sil ls in the metamor­ phic complex, or extrusions on the vergc 01" the devon­ ian carbonate rocks. upper permian con tin en tal and lagoonal deposits which unconfo rmably overli e older palaeozoic rocks pass continously into lower and mid­ dle triassic deposits. the vein and metasomatic barite deposits of the kresevo area arc located almost exclu­ sively in the devonian carbonatc rocks, and as such rep­ resent the largest barite accumuiation in the palaeozoic rocks of the dinarides. thc main gangue mineral is barite (over 95 wt. %), locally with rhombohedral cal­ ci te, octahedral lluorite and siderite. the main ore min­ eral is mercurian tetrahedrite. barite contains average 4.19 wi. % srs04 (an average or 56 samples). its aver­ age su lphur isotope composition from 40 analyses is +9.48%0 (jurkovic, 1987; jurkovic et ai., 1995). 2r 3. methodology the following methods were used: x-ray powder diffraction (xro), optical emission spec troscopy (oes), chemical gravime tric analysis and proton micro­ probe, part icle induced x-ray emission (pixe) analysis. xrd patterns were produced using a philips dif­ fractometer, with a proportional coun ter and graphite m onoch romator, using cuka radiation. uniquely indexed diffraction lines 410,32 1,303 and 004, all in the region from (-) = 22° to (-) = 26°, were lised in calcu­ lation or the parameters of the orthorombic unit-cell. the angular scale of the diffractometer was corrected by li sing quartz as the internal standard and its diffrac­ tion line 112 at e ~ 25.070° for cuka, radiation (the corresponding interplanar spacing being d ~ 1.8178 a; borg & smith, 1969). the homogenized mixture of barite and quartz contained ===15 wi. % quart z. operat­ ing condi tions were a divergence slit and rece iving slit o r 10 ancl 0.2 111111, respectively; scan rate or 1/2 0 per minute; chart speed of 10 mol/minute; a full scale of i x 103 cps; and a time constant of j see. three patterns were produced for each sample. the position of the quartz diffraction line 112 as well as the barite diffrac­ ti on line 004 for the cuka 1 radiation (several barite samples have the diffraction line 004 resolved in the spectral double t components) were measured at 4/5 of their he ighl. the posi tions of the non-resolved barite diffracti on line 004 (most of the samples) as well as the positions of the barite diffraction lines 410,321 and 303 for the cuka radiation were meas ured at 1/2 of their height. mole% srs04 sample locality determined derived no. by des from doo4 baso,-synth. <0.1 0.0+0.3 1 martinovac 0.3±0.1 o.4±0.3 2 tocak 1.4±0.1 1.6±o.4 3 radesa 1.6±o.1 0.9±o.4 4 cvjetnjak 2.9±0.2 2.5±0.3 5 ravni vaganac 3.5±0.2 4.2±o.5 6 tocak 5.4±0.4 6. 1±0.4 7 martinovac 7.0±0.4 6.7±0.5 8 gusta suma 8.1±0.5 8.6±o.4 9 gusta suma 8.6±o.5 8.3±0.4 10 dubrave-dugi dol 8.7±0.5 8.1 ±0.3 11 donjr martrnovac 9.6±0.5 8.8 ±0.5 12 brjele jame 12.8±o.7 12.4±0.4 13 bijele stijene 15.7±o.8 15.5±o.4 14 kolovoje 17.6±0.9 18.3±0.3 gcologkl croatica 50/1 barite samples prepared for chemical analysis were proven free of xrd detectable impurities. any negligi ­ ble calcite and dolomite admixtures were removed by acid treatment. t he purity control of' the selected barite samples by oes showed numerous ba lines in all samples, several strong or weak sr lines depending on the s trontium con­ tent , and some weak lines of ea and pb in all samples. the chemical analysis determined all the samples as su lphates. due to the purity of the samples the quantita­ tive cstimation of barium and sulphate was not neces­ sary. the strontium content was dctermined by oes, using barium as an internal standard and measuring the intensi ty ratios of spectral lines in selected line pairs, espccially srn 338.07 nm ban 277.14 nm and sri 335.l3 nm bal 335.68 nm (s iffar, 1975). for the purpose of check ing the analytical data from siff ar (1988) and [or new samples, four selected barite sam­ ples with s trontium contents highe r than 7 mole % were analyzed aner dilution with equal amounts of pure bari­ till} sulphate containing less than 0.1 wt. % of strontium sulphate. the analyses wcre performed by oes, and by a chemical gravimc tric method involving the precipita­ tion of barium as bariulll chromate from a homoge­ neous solution, with subsequent gravimetric determina­ tion of sr as stront ium sulphate (following the method of gordon et ai. , 1959). thi s chemical mcthod is vcry time-consuming and not suitable [or routine analy­ sis, howeve r the results arc somewhat better than by oes. every samplc in the present study was analyscd three times by oes and the above mentioned samples also by the chcmical method. d""ia ala bla cia 1.7890(2) 8.879(2) 5.456(1 ) 7.156(1) 1.7887(2) 8.879(1 ) 5.454(2) 7.155(1) 1.7878(3) 8.878(3) 5.455(2) 7.151 (1) 1.7883(3) 8.875(3) 5.453(1 ) 7.153(1 ) 1.7871 (2) 8.886(2) 5.455(1 ) 7.148(1 ) 1.7858(4) 8.856(2) 5.451 (2) 7.143(2) 1.7843(3) 8.849(1 ) 5.451 (2) 7. t 37(1) 1.7838(4) 8.842(2) 5.453(2) 7.135(2) 1.7823(3) 8.831(1) 5.446(2) 7.129(1) 1.7826(3) 8.839(3) 5.443(2) 7.130(1 ) 1.7827(2) 8.834(1 ) 5.452(2) 7.131 (1) 1.7822(4) 8.825(2) 5.446(1 ) 7.129(2) 1.7794(3) 8.803(1 ) 5.448(1 ) 7.1 t8(1) 1.7770(3) 8.795(3) 5.443(2) 7.108(1 ) 1.7748(2) 8.765(2) 5.446(1 ) 7.099(1 ) table i. locality, slrontilllll content, imerp lanar spacing d(}1)4 and la llice constants of natural barites from the kresevo area and the synthetic baso.;' samples 1.3.4,7. ii and 14 correspond 10 the samples k 2c, k 12. k 19, k 2<1, k 3 and k 26b (siftar, 1988). respectively. sam­ ple 9 corresponds on ly !o the fine-grained pari of barite sam pl e k r (s iftar, 198r). the si" contcnt of the samples 8, 11, 13 and 14 was also delennined by the chemical £l"llvim c!ric method which gave the fotlowin£ resu lt s (mole % srs0 4 ): 8.0to.3, 9a±oa, is.6toa, 17.s ±o.s, respectively. slovcncc. silbr. j:lksic & jurkovic: strontium dcpendence ofthc ~liiicc constants of bariles ... 29 " !2 <:> v <:> j oj ..., j '" ..., ~ '" q b c ixlo jcps 26 25 24 23 22 8/', cuk" fig. i xrd pa1!erns of lhe sampl es, in the reg ion from 22" 10 26° (0): a syn lhel ic 13aso~; b samp le 14; c sample 7. the angular position of lhe quartz diffraction li ne 11 2 (used fo r the angular scale c<ll ibration) is show n by lhe arrow . calcium and lead conte nts were determ ined by oes comparing the in tensities of ea and pb li nes with those in the s tandards containing know n amou nts o f lhese clements. two bari te samples were analysed lis ing the foclised proton mi c robeam and pjxe spectroscopy. the mea­ surements were made using a 3mey proton beam from the tandcm van de graarf accele rator in the ruder boskovi c in s titute. the nuc lea r microp robe fac ilit y desc ri bed e lsewhere (laksic e t ai., 1993; ryan & gr ifrin, 1993) foc used the beam to a spatial resolu­ tion oj' 5 pill with a beam current of 100 pa. the beam was scanned linearly across the sample surface. c harac­ teris tic xrays were de tec ted using the semiconductor si( li ) detec tor. from the total pjxe spectrum , counts be longing to a particular x-ray line were recorded usi ng thc mu ltipa rame te r data acqu is ition sys tem. the pos it ion or the beam at the time of an event is a lso recorded. data were the n displayed as a dis tribution of xray line in tens it y across the particular line, for each or the lines observed ill spectrum. in thi s a rt ic le only the s tron tium la line resul ts were present ed due to the lowe r sampling depth (5 pm) w hen compared to the strontiulll ka line. 4. results and discussion locality, sr-contcnt, inte rplanar spacing d(yj.) ancllat­ ti ce constants or fourteen natural bar ites as wei! as the data fo r synthet ic bas04 arc g ivcn in table 1. the nat­ ura l samples contained from 0.3-17.6 mo le % srs04 • the fract ions o f ca and pb, which can a lso replace ba in the c rysta l s truc lure, were negl ig ible; the samples contained less than 0.03 wt. % ca and less than 0.02 wt. % pb, thus representing almos t pure (ba,sr)so<) solid soluti ons. diffrac ti on lines of some natural samples were almost as sharp as those of the sy nthe tic baso" (fig. la , b). however, diffraction lines oj" other samples were not so well-defined, and the lines or samplc 7 were sub­ stantially broadened in rclation to synthet ic bas04 (fig. ic). the widths at half maximum or the peak inte nsity were measured for s tron g diffraction lines 002 at 8 = 12.5° and 2 11 at 8 = 14.5° of all the samples, and com­ pared with those of synthet ic baso,) . it was found that the w idths of synthetic baso" and samples i , 8, 10, 13 and 14 were s imilar. the widt hs of diffraction lines o f sample 7 were the biggest (about 30% bigger than those of synthetic bas04), and the widths o f d iffraction lines of othe r sampl es were up to 10% bigger than those of sy nthe ti c bas04 • the observed broadeni ng m ay be attributed to composi ti onal heterogene ity (e .g . to the inhomogeneous distribution or sr). h yd rothe rmal barites may even reveal mi c rohc terogene ity (e.g. leeder et a i., 1983). conseque ntly, c rys tallites or the ir parts, in a given xrd powdered sample may have different concentrations of sr, and thus have s lightl y different lattice constants caus ing the broadening of dif­ frac tion lines. profiles of sr de termined by pixe along li ncar tra­ verses (fig. 2) show cons iderable composi tio na l c hanges in sample 7 (the broadening o f difrrac tion lines is about 30%), and lower observed he tcrogeneity in sample 9 (the broade ning of diffraction lines is about 6%). a polished surface of the fine-grained barite sam ­ pic 9 (bari te g rains are smalle r than 0.6 111m in diame­ te r) was profiled by pixe a long an arbitrary linear tra­ verse. the cleavage parti c le of tabul a r barit e 7 was a nalysed; profiles shown in fi g. 2 were take n on the poli shed cleavage plane (001) alon g the s traight line whic h bisec ts a sha rp angle (=78°) between c leavage planes 1210 ), e.g. along [010]. profiles of sr were a lso taken on the cleavage plane (2 10) along the s trai ght line perpcndicular to [00 i j. these profiles show a relatively homogeneous d istr ibution o f si'. the obscrved features o f sam pl e 7 indicate the zonatio n w ith di scontinuity planes paralle l to 12!o i. the un it -cell parame te rs of a g iven sample wcre obtained as follows. firstl y, the parameter c was deter­ mined from the interplanar spac ing dq04. nex t the para­ meter a was found from the inlerpl anar spac ing d3fjj and the already obtaincd parameter c. the parameter b was then calc ulated using the previously determined val ues or a and c and the interplanar spacings dj 10 (b , was cal­ c ulated) and dm (b2 was calc ul ated); b (th e value in tab le i) = (h, + 2"2)/3. the dependence of the unit -ce ll parameters or the kresevo barites on the s trontiulll con te nt is s hown in 10 geologia cro:llica 50/1 4~-----~ 4~-----~ 4~-----~ 0 0 200 400 600 800 distonce i flm 4 3 wlii~1~~~1\\! ~ ~2 l vl 1 3 ::2 ~ ;: vl 1 o 200 400 600 800 distoncefllm 4~~----~ ~: ~~~¥~~y ;: vl 3 ~2 l vl. 1 o 200 400 600 800 distancefllm fig. 2 distribution of strontium concentration across lhe surrace of barite 0 o sample 7 (upper profiles) and sample 9 (lower profiles). on a given sam0 200 400 600 800 o 200 400 600 800 pic the profiles were taken a long straight line, and the distances between distance/pm oistance/)lit1 individual profiles were 3 111m. fig. 3, which also shows the values of unit-cell parame­ ters of the natural samples found by wieser (1982), and of synthetic solid solution (ba,sr)s04 found by bostrom et al. (1967) and by burkhard (1973), as well as the values presented by goldish (1989). it can be observed that there are considerable differences bet ween the present values and those of the natural samples obtained by wieser (1982). the present val­ ues arc in agreement with those of bostrom et al. (1967), and especially with those of goldlsh (1989), who synthesized (ba,sr)s04 crystals with 25, 50 and 75 mole % srs04 . from the unil~cell parameters of these crystals and those of bas04 and srs04 (g iven on pdf ca rd 24-1035 and pdf ca rd 5-593, respect ively), and taking into account deviations of unit -cell parameters from linear relations (deviations from vegard's law), goldish (1989) derived unit-cell parameters for intermediate compositions (between 0. 1 and 0.9 mole fraction) at intervals of 0.1 mole fraction . however, fig. 3 shows that the present va lues of the unit-cell parameters arc rather different from those of all. 0 8.90 bla \ \ \ \ " • \0 8.85 \ 5.50 \ 0 \ 0 ---• 0 --~ ~o ---0 '0, 0 0 oj' 8.80 . \ 545 0'. \ \ \ • q \ 8.75 5.40 0 10 20 0 10 20 mole %5r50, mole %5r504 synthetic crystals obtained by burkhard (1973). for example the difference between the c parameters for pure bas04 is 0.015 a, or 0.21 %; i.e. it is greater than the experiment,,, error. burkhard (1973) deter­ mined the parameters using single crystals, the parame­ ter b from precession diffraction patterns, and parame­ ters a and c from weissenberg diffraction patterns, fol ­ lowing the method proposed by christ (1956). as a hi gh accuracy was c laimed for christ's (1956) method, the parameter c was in the present work deter­ mined by two addi tiona l procedures described in the fo llowing paragraph. sample 1 was very close to pure bas04, containing only 0.3 mole % srso, (table i). a single crystal of this sample, having the planes [dol) parallcl to its sur­ face (approx. 7x5 mm 2 ), was used to detect a series of sharp diffraction lines 001 at high bragg angles (8)50°) for the rad iations cuka p ka2 and kf31 by means of the counter diffractometer wit hout the monochromator. from the observed bragg angles approximate values of the c parameter were fou nd. in order to minim ize syscia 7.20 7. 10 705 0 0 , ''q , ' 00 ,0 ,0 'u , , "• 0, 10 20 mole %5rs04 fig. 3 depcndcncc of the unit -cell parametcrs {/, /; and c on sr content in so­ lid solutions (ba,sr)so.j : empty circlcs natural samples (wieser, 1982); cmpty squares and dashed lines synthetic crystals (burkhard, 1973); full lines synthctic crystals (bostrom ct ai. , 1967); crosses thc values pre­ sented by goldtsh (1989); full circles nat ­ ural samplcs (from illis study) . slovcm;c, siftar, jaksic & jurkovic: strontiuml)epenclcncc of ihe lattice constanls of baritcs .. . j i 1.785 • 1.780 1775 o 5 10 15 20 mole 'io5r504 fi g. 4 the values of interplanar spacing (/001 vs. composition: full cir­ c les synthetic bas04 and natural samples (from this study): crosses the values derived from the data presented by gold­ [si-[ (1989). the straight linc is filled to the values derived from thc data presellted by goldlsh (1989). temmic errors, a graphical extrapolation toward e:::: 90° was applied using the function cose·ctge. a value of 7.155 a. was obtained for parameter c, being ~qual to the value given in table 1, but derived from the inter­ planar spacing doo4 ' using the angular separation of neighbouring diffraction lines 001 and following the method proposed by popovic (1973), in which most of systematic errors are minimized, a value of 7. 154 a. was obtained from four pairs of diffraction lines having e> soo. besides, it should be stressed that the present values of synthetic bas04 (table 1) are in very good agreement with those for baso" given on the pdf card 241035. there are several methods or sr determination by xrd in barites based on measurement of particular interplanar spacings. for instance, the d2 11 spacing was recomillended by goldlsh (1989) and the d]02 spac­ ing by osacar et al. (1991). the value of the inter­ planar spacing doq..t (quartz was used as internal standard for the angular scale calibration) tested on the samples from krcsevo area also appears satisfactory in the determination of sr in natural barites . on the pdf card 24 1035 the relative intensity or the diffraction line 004 is only 4% , and this line is therefore considered as unusable. however, barite has exccllcnt cleavage along 100 i j, and the powdered sam­ ple in the specimen holder has a high degree of prefer­ entially oriented grains. as a result the intensity of the diffraction line on the pattern obtained by the diffrac­ tometer will be several magnitudes higher than that according to pdf data, especially if the surface of the sample is well "polished". the xrd patterns of three samples prepared in this way are shown in fig. 1. in the range from 0 to ::=20 mole % srs04 (the range investi­ gated in this study) the angular distance in e between the diffraction line 004 of barite and the 112 diffraction line of quartz is smaller than 0.8°, which practically excludes systematic intstrumental errors. besides, the 112 diffraction line of quartz as well as the diffraction line of relatively homogeneous barite are resolved in a spcctral doublet which allows a high accuracy of dif­ fraction angle e measurement. quartz is a very suitable mineral and often occurcs in barite ore samples. the dependencc of the interplanar spacing d oo4 of barites from the kresevo area on strontium content is shown in fig. 4, which also shows the correspond ing value of synthetic baso" (this study), as well as the values derived from the data presented by goldish (1989). between goldish's values we can fit a straight line which deviates about ±o.oooos a, corresponding to about 0.06 mole % srs04 • the value of synthetic bas04 as well as the values of natural samples plot very ncar to this straight line showing (a) a relatively good agreement of oes and xrd data, and (b) that the diffraction line 004 may be used for detcrmination of the sf content of barites. an approximate concentration of sr in the range [rom 0 to ~ 20 mole % srso" may by determined from the diagram on fig. 4, or using the equation: d()(j4(a) :::: 1.78903 0.07782 x s (s = illole fraction srso,). a homogeneous sample has a diffraction line 004 clearly resolved in the spectral doublet components, and the estimated error of d oo4 is ±0.0002 a, corre­ sponding to an absolute error of about ±0.3 mole % srs04 in sr determination, according to fig. 4. howev­ er, the 004 dirfraction line or most samples from the bosnian deposits is broadened and not so well-defined. in these cases the spacing value is measured with an error not exceeding ±0.0004 a. . in this case the absolute error is ::; ±o.s mole % srs04 , i.e. from ±oa to ±o.s mole % srso, cfable l). the values of the sr content of the kre.sevo barites derived from the xrd data arc compared with thc oes data in table i. the described method of xrd determination or sr is similar to that proposed by goldisi-i (1989) who recommended using diffraction line 211. this very sharp diffraction line for pure bas04 is at e::= 1404° , while the diffraction line 004 is at e ~25 . 5°. we observed that with the same measurement of accuracy of the diffraction angle e the absolute error in mole % srs04 is about two times higher when the diffraction line 211 is used, compared to the results obtained by the usc of the dirrraction line 004. osacar et a1. (1991) proposed the strong dillrac­ tion line 102 of barite and halite (nael) as the internal standard (its diftraction line ii j), for xrd determina32 l ion of sr in ihe range from 0 10 j 2 mo le % srs04 • accord ing 10 osaca!" c t ai. , thc absolutc erro r is ±o. 5 mole % srs04 in sr determination. the recording time for one sample is 10 mi nutes . the advan tage of this me thod is the recovery of the ori ginal sample aft er the analys is by dissolving the nael in water. the main dis­ advantage of this met hod is that the strongest line of quartz is part ial ly superimposed with the 102 di ffrac­ tion li nc of barite. 5. conc lusion the proposed method of s r determ inat ion in barites may be applied as rout ine analys is s ince it provides rapid detenni nat ion for a set of samples. in the cases of considerable sa mple heterogenei ty (sec sample 7) the average concentrati ons of sr obt ai ned by x rd and chem ical ana lysis arc comparable. the method aids in the tes ting of poss ible rough errors obtained by diffcr­ ent chem ical analyses. moreover, the comparison of the w idt hs of corres ponding d iffracti on lines for a g iven sample and pu re bas04 may give informat ion about the re lat ive inhomogene ity of sr distribution in the sample. different pan s of even very small hyd roth erm al barite fragments may have very differe nt sr contents. due to th is it is oj" essential importance that the same homogenized sample is used for different types of ana lyses. in contrast, d iscrepancies can occur in the results of complementary analyses. 4. references borg. l. y. & sm ith, d.k. (1969): calculatcd x-ray powdcr patterns fo r s ilicate mi nerals.geological society of amcrica, boulder, colorado, 896 p. bostrom, k. , frazer, j. & blankenburg, j. (1967): subsolidu s phase relations and lattice con­ stant s in the sys tcm bas04-s rs04-pbs04.arki v mineral. geol. , 4, 477-485. bu rkhard, a. (1973): optische und rbntgenogra­ ph ischc untersuchungen am system 3aso'i-srs04 (ba ryt·coeles tin).schweiz. min. pctr. mitt. , 53, 185197. chr ist, c.l. (1956): precision dete rmination of lat­ ticc constants of s ingle c rystals us ing the conven­ tional weissenbcrg camcra.amer. miner., 4 1, 569580. goldis h, e. ( 1989): x·ray diffrac tion analysis of bar· ium-stron tiu m sulfate (bari te-ce lestite) so li d sol u­ tions.· pow. dirr. , 4, 214·2 16. geologia croatica 5011 gordon, l., salutsky, m.l. & willard, h.h. ( 1959): the precipi tat ion from homogeneous solu­ ti on.wiley, new york, 187 p. jaks ic, m. , kukec, l. & ya lkoyic, y. ( 1993): t he zag reb nuclear microprobe faei lity. nucl. instr. and meth ., b77, 49·5 1. joy anoyic, r., moj icey ic, m., tokic, s. & rok ic, l j. (1977): osnov na geoloska karta i: 100.000. tumac za list sarajevo k34· 1 (geo logy oj" sarajevo sheet).inst itu\ za geoloska ist razivanja sarajevo i zavod za inzenjersku gcologiju i hidroge­ ologij u gradev inskog rak ulteta sarajevo (1970· 1974). say. geol. zavod, beograd, 52 p. jurkoy ic, l. (1987 ): barite depos its on mou nt meduv rsje sou th and south-eas t of the town of kresevo, bosni a.· geol. vjesnik. 40,3 13-336. jurkoyic, i. . pali nkas, l., sloyenec, d., siftar, s. & pezdlc, j. (1995): paragenes is, geochemistry and crysta ll ochem ist ry of the ba ri te de posits in the bosnian sch ist mounta ins. eug-8, april 1995, strasbourg, terra abstracts, 7, 331. strasbourg. leeder, 0 ., baum, h. & hung er . h.-j. (1983): heteroge ner s tro ntiu l11c inbau in b aryl.z. geo l. wiss., ii . 113711 40. osacar. m.c., besteiro, j. & gonzales , j. ( 1991): x·ray diffraction analysis of strontiu m in barites.· pow. diff. . 6, 70-73. popoy ic, s. (1973): un it -ce ll dimension measu re­ ments from pairs of x-ray diffrac tion lines.1. app \. crys\. , 6,122128. ryan, c.g. & griffin, w. l. (1993): the nuclea r microprobe as a tool in geology and mineral explo­ ra tion.nuel. instr. and meth., b77. 38 1-389. siftar, d. (1975): determi nation of stront ium in barite by spectrochemica l meth od .zborni k radova rud arsko-geol osko·na ftn og fakuitcta, 45-49. zag­ reb. s iftar , d. ( 1988): the chemical characteris ti cs of bari te from some bosnian deposit s.rudarsko­ metalurski zbornik, 35, 75-89, ljubljana. wieser, t. (1982): barites and cclcstoba ritcs in th c fl ysch or the polish carpath ians. archi wull1 miner­ alogiczllc, xxxylll , 13-27. manuscript received november 11, 1996. revised manuscript accepted april 28, 1997 . gc-60-2.indb 1. introduction the upper cretaceous–lower tertiary rocks are widely distributed all over the eastern desert, extending from gebel shabrawet in the north, through the gebel ataqa and galala massifs, to wadi qena in the south. in the north eastern desert (gebel shabraweet), these rocks are greatly affected by movement of the syrian arc which gradually diminishes southward in the galala massifs until its effect is very reduced in wadi qena. several palaeozoic–jurassic outcrops are exposed on the foot slopes of the galala massifs through wadi araba and underlie the cretaceous–eocene rocks. the campanian–early eocene deposits are of carbonate platform facies type that predominate in both campanian–early eocene stratigraphy of the southern galala plateau, eastern desert, egypt ahmed aly ismail, yasmine hussein-kamel, mohamed boukhary and ahmed abdel aziz ghandour galalas. the distribution of planktonic and larger foraminifera within the investigated succession allowed an integrated biostratigraphic study to be achieved. generally, several authors have been involved with the stratigraphy and palaeontology of the southern galala plateau, e.g. farag (1954), awad & abdallah (1966), abdallah & eissa (1971), abdallah et al. (1971), mazhar et al. (1979), kuss (1986), kuss & leppig (1989), selima & askalany (1996), keheila (2000), scheibner et al. (2000, 2001), and ismail & boukhary (2001). there are no publications from the study area, 20 km west of saint anthony monastery (fig. 1) to nearly the western part of the southern galala plateau. for this reason, the following aims were selected for the study area: (1) to carry out a detailed stratigraphic analysis including lithostratigraphic units and biostratigraphic zones in order to increase the understanding of the nature of the basin of deposition in the southern galala plateau during the late cretaceous–early eocene time. (2) to determine the relationship between horizons yielding smaller foraminifera (planktonic and benthonic) and those yielding larger ones in order to understand why the southern galala has different facies from those recorded in the western desert and in sinai during the same interval. 2. material and methods a total of 91 rock samples were collected from two surface sections covering the campanian–early eocene succession in the western part of southern galala plateau. the first section, umm khayshar (uk) lies 20 km west of saint anthony monastery, and is 139 m in thickness. the second, umm damaranah section (ud) is located 30 km west of saint anthony monastery (197 m thickness). forty nine samples were collected from the umm khayshar section covering the campanian–maastrichtian, while forty two samples were collected from the umm damaranah section covering the campanian–early eocene succession. the collected samples were described and washed for separating microfossils. these microfossils (plank geologia croatica 60/2 115–137 11 figs. 4 pls. zagreb 2007 key words: larger foraminifera, campanian–early eocene, southern galala plateau, eastern desert, egypt. geology department, faculty of science, ain shams university, abbassia 11566, cairo, egypt; e-mail: aaaismail2002@yahoo.com abstract several species of larger foraminifera have been recorded in the campanian–early eocene succession of the southern galala plateau. these species include orbitoides media (archiac), omphalocyclus macropora (lamark) in the campanian–maastrichtian rocks (gebel thelmet formation and sudr chalk) and fallotella (fallotella) kochanskae persica hottinger & drobne, fabularia zitteli hottinger, alveolina pasticillata (schwager), glomalveolina dachelensis (schwager), miscellanea rhomboidea kuss & leppig and nummulites cf. subramondi de la harpe in the palaeocene–early eocene sediments (southern galala formation). there are few intervals yielding planktonic species that contributed significantly to the determination of the age assignment for the larger foraminifera. these species include globigerina triloculinoides plummer, morozovella uncinata (bolli), morozovella trinidadensis (bolli), morozovella cf. conicotruncata (subbotina), morozovella angulata (white), planorotalites pseudomenardii (bolli) and acarinina primitiva (finlay). these planktonic species placed the glomalveolina dachelensis (schwager) zone as being older than the morozovella angulata (white) zone (early–middle palaeocene). the occurrence of the algae ethelia alba (pfender) and neomeris plagnensis deloffre further supports the referred age. 116 geologia croatica 60/2 tonic and benthic foraminifera) were identified, photographed by scanning electron microscope (sem) and are illustrated in four plates. for larger foraminifera, normal photography was used. some samples were prepared for thin-sections to study the larger foraminifera, in addition some thin-sections were made through the free tests of these foraminifera. it is worth mentioning that the umm khayshar (uk) section starts with the coniacian– strike and dip of fig. 1 location map (a) and geological map (after ghandour, 2000) of the study area (b). a b 117ismail et al.: campanian–early eocene stratigraphy of the southern galala plateau... galala formation (cenomanian), maghra el hadida formation (turonian) and matulla formation (coniacian–santonian), which have been treated elsewhere (ismail et al., in press). 3. stratigraphy the stratigraphic analysis of the studied rocks depends mainly on the distribution of foraminifera through the campanian–early eocene succession. in intervals that lack foraminifera, macrofossils were used whenever possible. the identified foraminiferal assemblages include planktonic, small benthonic and larger foraminifera that were extracted from the umm khayshar and umm damaranah measured sections (figs. 2, 3 & 10). the identified foraminiferal assemblages were correlated with the standard cretaceous biozones of caron (1985) and the standard palaeocene–eocene biozones of toumarkine & luterbacher (1985). furthermore, the rock units in the study area are the gebel thelmet formation, sudr chalk and southern galala formation (figs. 4 & 5). the lithostratigraphic description, in addition to the faunal content (figs. 6 & 7) is discussed below. 3.1 late campanian–early maastrichtian deposits sediments of late campanian and early maastrichtian age are widely distributed in the upper parts of the southern galala plateau and the foot slopes of the northern galala plateau facing wadi araba. in the lower part they are composed of well-bedded flaky limestone intercalated with chalk and sandstones. in the upper part they consist of fossiliferous, chalky, sandy and argillaceous limestones intercalated with green shales. the thickness of this interval reaches 69 m in the umm khayshar section and >40 m in the umm damaranah section. the interval is named the gebel thelmet formation by abdallah & eissa (1971) at gebel thelmet, southern galala. it contains some larger foraminifera of stratigraphic significance. in the umm khayshar section, the sequence is characterized by the abundance of orbitoides media (archiac) and omphalocyclus macroporus (lamarck) and overlain by a horizon containing several planktonic and small benthic foraminiferal species of late campanian– early maastrichtian affinity: haplophragmoides calculus cushman & waters, h. excavata cushman & waters, h. globulosa lozo, h. hausa petters, ammobaculites subcretaceus cushman & alexander, a. texanus cushman, cyclammina cancellata brady, heterohelix glabrans (cushman), globigerinelloides prairiehillensis pessagno, hastigerinoides subdigitata (carman), rugoglobigerina macrocephala bronnimann, bulimina kickapooensis cole, b. reussi morrow, discorbis beadnilli said & barakat, anomalina umbonifera (schwager) and gyroidinoides goodkoffi (trujillo). the sugfig. 2 a general view of umm khayshar section. fig. 3 a panoramic view of umm damaranah section. fig. 4 a field photograph showing the sudr chalk (sc) formation and the unconformably overlying southern galala formation (sg). (sg) (s) 118 geologia croatica 60/2 gested early maastrichtian age may be partially equated to the globotruncanella havanensis zone. in umm damaranah, the presence of the larger foraminifera orbitoides media (archiac) and omphalocyclus macroporus ascribe the upper part of the gebel thelmet formation to the late campanian (ismail & boukhary, 2001). it is overlain by a nonfossiliferous sequence of chalky limestone, which suggests the extension of its age to the early?–middle palaeocene as evidenced by the appearance of glomalveolina dachelensis (schwager) and fallotella (f.) kochanskae persica hottinger & drobne. 3.2 early maastrichtian deposits the chalky deposits are widely distributed within this interval, named the sudr chalk by ghorab (1961) in wadi sudr, west central sinai. in the study area, it ranges from the first occurrence of globotruncana aegyptiaca nakkady to the first occurrence of the oysters exogyra overwegi boch and e. cornuarietis coquand (middle maastrichtian). the thickness of this interval is 45 m, and it overlies the horizon yielding orbitoides media (archiac) and omphalocyclus macroporus (lamarck) of the late campanian, and underlies a shallow carbonate horizon yielding the oysters exogyra overwegi and e. cornuarietis of the middle maastrichtian. the associated foraminiferal assemblage is composed of pseudoclavulina maqfiensis le roy, dentalina colei cushman & dusenbury, d. communis (d’orbigny), lenticulina muensteri (roemer), heterohelix globulosa (ehrenberg), h. moremani (cushman), h. striata (cushman), globigerinelloides prairiehillensis pessagno, g. subcarinata (bronnimann), hedbergella holmedlensis olsson, globotruncana aegyptiaca nakkady, g. bulloides volger, g. linneana (d’orbigny), contusotruncana fornicata (plummer), globotruncanita stuarti (de lapparent), archaeoglobigerina blowi pessagno, rugoglobigerina macrocephala bronnimann, r. rugosa (plummer), bulimina kickapooensis cole, b. reussi morrow, bulimina sp., cibicides praecursorius (schwager), anomalina umbonifera (schwager), anomalinoides nakkadyi said & kenawy, a. sinaensis said & kenawy, heterolepa hispaiolae (bermudez) and gyridina cf. subangulata (plummer). 3.3 middle maastrichtian deposits these deposits are only recorded at the umm khayshar section where they occupy the upper part of the sudr chalk. the thickness of this interval attains 30 m. it overlies the globotruncana aegyptiaca interval zone of the early maastrichtian and unconformably underlies the nummulites cf. subramondi–alveolina pasticellata horizon of the early eocene. this horizon yields the oysters exogyra overwegi and e. cornuarietis of middle maastrichtian age (luger, 1985), in addition to large gastropods. this horizon is equivalent to the gansserina gansseri zone of caron (1985), sigal (1977) and postuma (1971). there are a few beds yielding some long-ranging planktonic foraminiferal species – heterohelix globulosa, hedbergella holmedelensis and contusotruncana fornicate. 3.4 early?–middle palaeocene deposits early?–middle paleocene deposits are only recorded in the umm damaranah section and occupy the lower part of the southern galala formation. the thickness of this horizon is 127.5 m. it overlies the orbitoides media and omphalocyclus macropora assemblage zone of the late campanian and underlies the morozovella angulata zone of the middle palaeocene. this horizon is characterized by a large number of white globular larger forafig. 5 a field photograph showing the gebel thelmet formation (t) and the southern galala formation (sg) at the umm damaranah section. (sg) (t) m aa st ric ht ia n yp re si an s ud r c ha lk s ou th er n g al al a fm . fig. 6 stratigraphic column of the umm khayshar section (uk). 119ismail et al.: campanian–early eocene stratigraphy of the southern galala plateau... minifera glomalveolina dachelensis (schwager), in addition to miscellanea rhomboidea kuss & leppig and fallotella (f.) kochanskae persica hottinger & drobne. kuss & leppig (1989), equated the glomalveolina dachelensis zone to the alveolina (glomalveolina) levis zone of cuvillier & pomerol (1986), which is equivalent to the upper part of the planorotalites psudomenardii zone (early late palaeocene). in the umm damaranah section, this zone underlies the morozovella angulata zone of middle palaeocene age. this may suggest extension of the glomalveolina dachlensis zone downward to an early?–middle palaeocene age (figs. 8 & 9). 3.5 middle palaeocene deposits these are recorded in the umm damaranah section, which occupy the middle part of the southern galala formation. the thickness of this zone is 6 m. it overlies the glomalveolina dachlensis horizon of the early?–middle palaeocene and underlies the planorotalites peudomenardii zone of early late palaeocene time. this zone is of low diversity, where few species are recorded – morozovella angulata (white) and morozovella conicotruncata (subbotina), in addition to some badly preserved specimens of the same affinity. 3.6 late palaeocene deposits late palaeocene deposits are only recorded in the umm damaranah section, where they comprise the upper part of the southern galala formation and are 14 m thick. they overlie the morozovella angulata zone of middle palaeocene age and unconformably underlie the nummulites cf. subramondi and alveolina pasticellata (schwager) horizon of ypresian age. the associated fig. 7 stratigraphic column of the umm dammaranah section (ud). � 120 geologia croatica 60/2 assemblage includes planorotalites pseudomenardii (bolli), morozovella angulata (white), m. trinidadensis (bolli), m. uncinata (bolli), acarinina primitiva (finlay), nodosarella mappa (cushman & jarvis), reussoolina apiculata (reuss), globigerina triloculinoides plummer, cibicidoides padella (jennings) and cibicidoides cf. succedens (brotzen). 3.7 early eocene (ypresian) deposits these are recorded in the accessible, uppermost part of the southern galala formation in the two measured sections. in the umm khayshar section, these deposits unconformably overlie the exogyra overwegi–e. cornuarietis horizon of middle maastrichtian age. however, in the umm damaranah section, they overlie the planofig. 9 palaeogene zonations after berggren et al. (1995) and berggren & pearson (2005). berggren & pearson (2005)berggren et al. (1995) – – – – – – – – – – – – fig. 8 a correlation table of the rock units with the faunal content. 121ismail et al.: campanian–early eocene stratigraphy of the southern galala plateau... rotalites pseudomenardii zone of late palaeocene age. this interval contains the following species of ypresian age: nummulites cf. subramondi, alveolina pasticellata, fabularia zitteli hottinger and algae such as ethelia alba (pfender). 4. taxonomic notes this discussion includes the synonymy, special remarks and stratigraphic distribution for each species. for planktonic foraminifera the cretaceous scheme of caron (1985) and the palaeocene–eocene scheme of toumarkine & luterbacher (1985) have been followed, while several publications (e.g. henson, 1948; omara, 1956; said & kenawy, 1956; said & barakat, 1957; neumann, 1967; sliter, 1968; ismail, 1992; bolli et al., 1994, etc.) have been used for identification of benthic foraminifera. furthermore, the treatise of loeblich & tappan (1988) facilitated the classification of the different genera. the identified small foraminiferal species (fig. 11) were photographed by scanning electron microscope (sem) and the larger foraminiferal species, in addition to thin sections were photographed by a high power petrographic microscope, while normal photography was used for separated specimens. the larger foraminiferal species are illustrated in 2 plates. type specimens of the identified species are deposited in the geological museum of the department of geology, faculty of science, ain shams university, cairo, egypt (ismail collection). family heterohelicidae cushman, 1927 genus heterohelix ehrenberg, 1843 heterohelix glabrans (cushman) pl. i, fig. 1 1938 guembelitria glabrans cushman, p. 15, pl. 3, figs. 1 & 2. 1968 heterohelix glabrans (cushman) – sliter, p. 94, pl. 13, fig. 17. remarks: it has a subacute periphery, subrectangular chambers and smooth surface. distribution: in the study area, it is recorded from the umm khayshar section, sample uk 75, gebel thelmet formation (campanian). heterohelix striata (ehrenberg) pl. i, fig. 2 1840 textularia striata ehrenberg, p. 135, pl. 4, figs. 1a, 2a & 3a. 1985 heterohelix striata (ehrenberg) – caron, p. 60, pl. 24 (figs. 12 & 13). remarks: this species is easily distinguished by the fine striations on the surface of the test. distribution: in the study area, it is recorded from the umm khayshar section, sample uk 80, sudr chalk (maastrichtian). fig. 10 correlation between two studied sections. 122 geologia croatica 60/2 family globigerinelloididae longoria, 1974 genus globigerinelloides cushman & ten dam, 1984 globigerinelloides prairiehillensis pessagno pl. i, fig. 3 1967 globigerinelloides prairiehillensis pessagno, pl. 90, figs. 1 & 2. 1985 globigerinelloides prairiehillensis pessagno – caron, p. 47, fig. 29 (14–15). remarks: this species is characterized by globular chambers, which increase rapidly in size. distribution: in the study area, it is recorded from the umm khayshar section, samples uk 75 and uk 78, gebel thelmet formation (campanian), and samples uk 80 and uk 82, sudr chalk (maastrichtian). globigerinelloides subcarinata (bronnimann) pl. i, fig. 4 1952 globigerinelloides messinae subcarinata bronnimann, p. 44–45, pl. 1, figs. 10–11. 1985 globigerinelloides subcarinata (bronnimann) – caron, p. 47, fig. 29 (16–17). remarks: this species possesses an imperforate peripheral band in all chambers of the last whorl. distribution: in the study area, it is recorded from the umm khayshar section, sample uk 84, sudr chalk (maastrichtian). hedbergella holmdelensis olsson pl. i, fig. 5 1964 hedbergella holmdelensis olsson, p. 160, pl. 1, fig. 2. 1985 hedbergella holmdelensis olsson – caron, p. 59, fig. 25 (10–11). remarks: this species is characterized by its compact arrangement of the subglobular chambers. distribution: in the study area, it is recorded from the umm khayshar section, samples uk 80 and uk 100, sudr chalk (maastrichtian). family globotruncanidae brotzen, 1942 genus globotruncana cushman, 1927 globotruncana aegyptiaca nakkady pl. i, fig. 6 1950 globotruncana aegyptiaca nakkady, p. 690, pl. 90, fig. 20. 1985 globotruncana aegyptiaca nakkady – caron, p. 50, fig. 19 (1–3). remarks: it has 4 chambers in the last whorl and two closely spaced keels. distribution: in the study area, it is recorded from the umm khayshar section, sample uk 80, sudr chalk (maastrichtian). fig. 11 distribution chart of species determined at the um damaranah section. 123ismail et al.: campanian–early eocene stratigraphy of the southern galala plateau... globotruncana bulloides volger pl. i, fig. 7 1941 globotruncana linnei (d’orbigny) subsp. bulloides volger, p. 287, pl. 23, figs. 32–39. 1985 globotruncana bulloides volger – caron, p. 50, fig. 20 (1–2). remarks: this species is characterized by inflated chambers on both sides and two widely spaced keels. distribution: in the study area it is recorded from the umm khayshar section, sample uk 80, sudr chalk (maastrichtian). family rugoglobigerinidae subbotina, 1959 genus archaeoglobigerina pessagno, 1967 archaeoglobigerina blowi pessagno pl. i, fig. 8 1967 archaeoglobigerina blowi pessagno, p. 316, pl. 59, figs. 5–7. 1985 archaeoglobigerina blowi, pessagno – caron, p. 43, fig. 16 (3–4). remarks: it has 4 chambers in the last whorl and a rounded periphery. distribution: in the study area, it is recorded from the umm khayshar section, samples uk 80, sudr chalk (maastrichtian). genus rugoglobigerina bronnimann, 1952 rugoglobigerina macrocephala bronnimann pl. i, fig. 9 1952 rugoglobigerina (rugoglobigerina) macrocephala bronnimann, p. 25, pl. 2, figs. 1–3. 1985 rugoglobigerina macrocephala bronnimann – caron, p. 92, fig. 14 (5–7). remarks: rugoglobigerina macrocephala bronnimann differs from rugoglobigerina rugosa (plummer) in having 4 instead of 5 inflated chambers in the last whorl. distribution: in the study area, it is recorded from the umm khayshar section, samples uk 75, gebel thelmet formation (campanian) and samples uk 80 and uk 82, sudr chalk (maastrichtian). rugoglobigerina rugosa (plummer) pl. i, fig. 10 1926 globigerina rugosa plummer, p. 38, pl. 2, fig. 10. 1985 rugoglobigerina rugosa (plummer) – caron, p. 72, fig. 34 (9–10). distribution: in the study area, it is recorded from the umm khayshar section, samples uk 80, sudr chalk (maastrichtian). family globorotaiidae cushman, 1927 genus planorotalites morozova, 1957 planorotalites pseudomenardii (bolli) pl. ii, figs. 1–3 1957 globorotalia pseudomenardii bolli, p. 77, pl. 20, figs. 14–17. 1985 planorotalites pseudomenardii (bolli) – toumarkine & luterbacher, p. 108, fig. 12 (3–4). remarks: this species has a biconvex lenticular smooth test and imperforate keel. distribution: in the study area, it is recorded from the umm damaranah section, samples ud 36 and ud 37, southern galala formation (middle palaeocene) and sample ud 39, southern galala formation (late palaeocene). family truncrotalididae loeblich & tappan, 1961 genus acarinina subbotina, 1953 acarinina primitiva (finlay) pl. ii, fig. 4 1947 globoquadrina primitiva finlay, p. 291, pl. 8, figs. 129–134. 1985 acarinina primitiva (finlay) – toumarkine & luterbacher, p. 116, fig. 17 (6 & 7). remarks: it has 4 chambers in the last whorl, and a small but deep umbilicus. the last chamber represents one half of the test and the surface is pustulose. distribution: in the study area, it is recorded from the umm damaranah section, sample ud 38, southern galala formation (late palaeocene). genus morozovella mcgowran, 1968 morozovella angulata (white) pl. ii, figs. 5 & 6 1928 globigerina angulata white, p. 191, pl. 27, fig. 13. 1985 morozovella angulata (white) – toumarkine & luterbacher, p. 111, fig. 14 (5–6). remarks: all chambers of the last whorl are angular conical. instead of a peripheral keel, delicate spines are concentrated around the periphery and the umbilical shoulders. distribution: in the study area, it is recorded from the umm damaranah section, samples ud 34, southern galala formation (middle palaeocene) and samples ud 38 and ud 39, southern galala formation (late palaeocene). morozovella cf. conicotruncata (subbotina) pl. ii, fig. 7 1947 globorotalia conicotruncata subbotina, p. 124 geologia croatica 60/2 115, pl. 4, figs. 11–13; pl. 9, figs. 9–11. 1999 globorotalia conicotruncata subbotina – olsson et al., p. 60, pl. 11, figs. 10–15. remarks: this species is characterized by its conicotruncate shape in lateral view, with 6 chambers in the last whorl and the chambers are angular conical. distribution: in the study area, it is recorded from the umm damaranah section, samples ud 34, southern galala formation (middle palaeocene). morozovella trinidadensis (bolli) pl. ii, fig. 8 1957 globorotalia trinidadensis bolli, p. 73, pl. 16, figs. 19–23. 1985 morozovella trinidadensis (bolli) – toumarkine & luterbacher, p. 110, fig. 13 (3–4). remarks: this species has 5 angular conical chambers in the last whorl and it also has a wide umbilicus. distribution: in the study area, it is recorded from the umm damaranah section, samples ud 37, southern galala formation (middle palaeocene). morozovella uncinata (bolli) pl. ii, fig. 9 1957 globorotalia uncinata bolli, p. 74, pl. 17, figs. 13–15. 1985 morozovella uncinata (bolli) – toumarkine & luterbacher, p. 110, fig. 14 (3–4). remarks: the early chambers of the last whorl are angular conical and the suture lines on the spiral side are strongly curved backwardly. distribution: in the study area, it is recorded from the umm damaranah section, sample ud 37, southern galala formation (middle palaeocene). family globigerinidae carpenter, parker & jones, 1862 genus globigerina d’orbigny globigerina triloculinoides plummer pl. ii, figs. 10 & 11 1926 globigerina triloculinoides plummer, p. 134, pl. 8, fig. 10. 1985 globigerina triloculinoides plummer – toumarkine & luterbacher, p. 117, fig. 19 (1–2). remarks: it has a trochospiral test with 3 globular chambers and the last one occupies one half of the entire whorl. distribution: in the study area, it is recorded from the umm damaranah section, sample uk 39, southern galala formation (late palaeocene). family orbitoididae schwager, 1876 genus orbitoides d’orbigny, 1848 orbitoides media (archiac) pl. iii, figs. 1–4, 6–7 & 11 1837 orbitoides media archiac, p. 178 2001 orbitoides media (archiac) – ismail & boukhary, p. 81, pl. 1, figs. 1–9; pl. 2, figs.1–4. remarks: it has a lenticular test, symmetrically biconvex, the megalospheric test has four-chambered embryo surrounded by thick wall, and its surface is smooth. diameter thickness maximum 4.6 1.4 minimum 2.2 0.7 distribution: it was recorded by faujas de saintfond (1802) from the maastrichtian of holland, and from the upper cretaceous of france by schlumberger (1901). although some authors considered orbitoides media to belong to the early maastrichtian (seronie-vivien, 1972, and andreieff & marionnaud, 1973), both historical and micropaeontological evidence ascribes these sediments to the late campanian (van hinte, 1965; goharian, 1971; van gorsel, 1973; platel, 1977, and lambert, 1980). in egypt, it was recorded from the campanian of gebel thelmet, southern galala by ismail & boukhary (2001). in the study area, orbitoides media is recorded from samples uk 66, uk 67 and uk 71 in the umm khayshar section, gebel thelmet formation, campanian, and samples ud 1, ud 2 and ud 3 in the umm damaranah section, also gebel thelmet formation, campanian. at the umm khayshar section, the beds which yield both orbitoides media (archiac) and omphalocyclus macropora (lamark) are overlain by beds containing planktonic foraminifera of early maastrichtian affinity (such as globotruncana aegyptiaca nakkady, globotruncana bulloides volger, globotruncana linneana d’orbigny, rosita fornicata plummer, archaeoglobigerina blowi pessagno, rugoglobigerina macrocephala bronnimann, rugoglobigerina rugosa bronnimann). therefore, orbitoides media (archiac) and omphalocyclus macropora (lamark) in the study area are of campanian affinity according to ismail & boukhary (2001). genus omphalocyclus bronn, 1853 omphalocyclus macropora (lamarck) pl. iii, figs. 5 & 8–10 1920 omphalocyclus macropora (lamarck) – douville, p. 209, pl. 8, figs. 5–14. 2001 omphalocyclus macropora (lamarck) – ismail & boukhary, p. 82, pl. 3, figs. 5–7. 125ismail et al.: campanian–early eocene stratigraphy of the southern galala plateau... remarks: it has a biconcave test, the megalospheric embryo is quadrilocular followed by cycles of arched equatorial chambers. distribution: omphalocyclus macropora was recorded from the upper cretaceous of libya by krumbeck (1906), from the maastrichtian of switzerland by renz (1937), from the maastrichtian of holland by neumann (1958), and from the maastrichtian of cuba by hanzawa (1962). in egypt, it was recorded from the campanian of gebel thelmet, southern galala by ismail & boukhary (2001). in the study area, it is recorded from samples uk 66, uk 67 and uk 71 in the umm khayshar section, gebel thelmet formation, campanian, and samples ud 1, ud 2 and ud 3 from the umm damaranah section, also gebel thelmet formation, campanian. family orbitolinidae martin, 1890 genus fallotella mangin, 1954 fallotella (fallotella) kochanskae persica hottinger & drobne pl. iv, fig. 11 1980 fallotella (fallotella) kochanskae persica hottinger & drobne, p. 239, pl. 15, fig. 15–29. remarks: it is characterized by its high conical form with horizontal partitions. the diameter of this specimen is 1.4 mm and its height is 1.5 mm. distribution: fallotella (fallotella) kochanskae persica was recorded from the palaeocene of iran by hottinger & drobne (1980), in association with alveolina (glomalveolina) dachelensis, miscellanea sp. and kathina sp. in the study area, it is recorded from samples ud 21, ud 22 and ud 32 in the umm damaranah section, (together with glomalveolina dachelensis and miscellanea rhomboidea), southern galala formation, middle palaeocene. family fabulariidae ehrenberg, 1839 genus fabularia defrance, 1820 fabularia zitteli hottinger pl. iv, fig. 7 1969 fabularia zitteli hottinger, pl. 8, fig. 97. remarks: this specimen has a milioline type of coiling in the early stage, becoming two-chamber growth in the adult stage. the adult stage is adapted to be of discoidal shape with only two chambers per whorl. distribution: in the study area, fabularia zitteli is recorded from the umm khayshar section (samples uk 102, uk 104, uk 106, uk 108 and uk 109), southern galala formation, ypresian, and from the umm damaranah section (samples ud 41 and uk 42), southern galala formation, ypresian. family alveolinidae ehrenberg, 1839 genus alveolina d’orbigny, 1826 alveolina pasticillata (schwager) pl. iv, figs. 8–9 & 12 1883 alveolina (flosculina) pasticillata schwager, p. 104, pl. 26 (iii), fig. 2. 1960 alveolina pasticillata (schwager) – hottinger, p. 88, pl. 4, figs. 26–33. remarks: the test is almost spherical, only slightly nautiloid whorls in the b-form are flosculinized circular. the last whorls have a thick basal layer. the early whorls are widely spaced while the last whorls are narrowly spaced. diameter in the b-form is nearly 2.8 mm, 7 whorls in radius 1.38 mm. aand b-forms are close in overall size or diameter. chamberlets in the last whorls are quadrate and beaded in the early whorls. in the a-form, the last whorls lack a thickened basal layer which is thin, chamberlets beaded all over the test, and the last whorls are narrowly separated, early whorls at regular step size. the proloculus is globular, the diameter of the protoconch is 0.16 mm, diameter of deuteroconch is 0.11 mm., diameter of the test is 3.05 mm, number of whorls per radius are 11 whorls in a radius of 1.44 mm. distribution: alveolina pasticillata was recorded from the early eocene of france by hottinger (1958). in egypt, it was recorded from the early eocene of egypt by schwager (1883), hottinger (1960) and kuss & leppig (1989). in the study area, alveolina pasticillata is recorded from both measured sections, umm khayshar section (samples uk 102, uk 104, uk 106, uk 108 and uk 109), southern galala formation, ypresian, and from umm damaranah section (samples ud 41 & uk 42), southern galala formation, ypresian. genus glomalveolina hottinger, 1962 glomalveolina dachelensis (schwager) pl. iv, figs. 1 & 2 1883 alveolina cf. ovulum schwager, p. 95, pl. 24, fig. b (a–c). 1980 alveolina (glomalveolina) dachelensis schwager – hottinger & drobne, pl. 15, fig. 2g. 1989 alveolina (glomalveolina) dachelensis schwager – kuss & leppig, p. 302, figs. 5 (a–b). remarks: the subgenus glomalveolina was raised to generic rank as it has characters which differ from alveolina. these characters include equidimensional test of nearly spherical outline and a test diameter of 2.5 mm. the diameter of glomalveolina dachelensis is less than that of alveolina (glomalveolina) levis whose diameter is 2.8 mm, thus this taxon exists in an older zone than that of alveolina (glomalveolina) levis and alveolina (glomalveolina) primaeva of the late palaeocene. 126 geologia croatica 60/2 distribution: hottinger (1960) described alveolina (glomalveolina) from its type locality (qasr dachl) in the libyan desert (egypt), as well as from gebel thelmet, southern galala, egypt. in both localities cretaceous deposits are transgressively overlain by sediments with alveolina (glomalveolina) dachelensis, operculina libyca and assilina sp. (kuss & leppig, 1989). in the study area these beds are overlain in the umm damaranah section by middle palaeocene rocks (with morozovella angulata and morozovella cf. conicotruncata). glomalveolina dachelensis is recorded from the umm damaranah section (samples ud 21, ud 22 & uk 32), southern galala formation, middle palaeocene. family pellatispiridae hanzawa, 1937 genus miscellanae pfender, 1935, 1952 miscellanea rhomboidea kuss & leppig pl. iv, figs. 4–6 1989 miscellanea rhomboidea kuss & leppig, p. 303, fig. 6(a–g). remarks: this genus is characterized by having alternating whorls, the first whorl with discoidal planispiral evolute coiling, the other whorls are of the spiroloculine type of coiling. the outer outline of the test is planispiral involute. there are two types of side pillars, the first type interfinger with the whorls while the other occurs over the whorls. in miscellanea rhomboidea kuss & leppig, the diameter of the megalospheric form reaches 1.7 mm. the megalospheric form of the protoconch is surrounded by two chambers in trilateral shape and the diameter of the protoconch is 0.312 mm. distribution: it was recorded from the middle palaeocene of the southern galala by kuss & leppig (1989). in the study area miscellanea rhomboidea is recorded from samples ud 21, ud 22 and uk 32 in the umm damaranah section, southern galala formation, middle palaeocene. family nummulitidae de blainville, 1827 genus nummulites lamarck, 1801 nummulites cf. subramondi de la harpe 1883 – schaub 1951 pl. iv, fig. 3 cf. 1883 nummulites ramondi, de la harpe, p. 173, pl. ii, figs. 5, 12 (form b). cf. 1883 nummulites sub-ramondi, de la harpe, p. 175, pl. ii, figs. 13–17 (form a). cf. 1951 nummulites subramondi de la harpe – schaub, p. 128, figs. 119–127. remarks: nummulites subramondi was probably derived from n. globulus (sensu schaub, 1981), as both have similar septa and chambers; our material is recorded only from thin section and can be compared with nummulites subramondi but due to the absence of external characters, the open nomenclature is used. distribution: this species was originally recorded from the thebes formation, gebel deir, near esna, nile valley. here, nummulites cf. subramondi is found together with alveolina pasticellata (schwager) and fabularia zitteli hottinger. in the study area it is recorded from samples uk 102, uk 104, uk 106, uk 108 and uk 109 in the umm khayshar section, southern galala formation, ypresian, and from the umm damaranah section (samples ud 41 and uk 42), southern galala formation, ypresian. green algae family dasycladaceae kutzing, 1843 genus neomeris lamouroux, 1816 neomeris plagnensis deloffre pl. iv, fig. 13 1977 neomeris plagnensis deloffre – deloffre et al., p. 41, pl. 5, fig. 5 (3–7). 1989 neomeris plagnensis deloffre – kuss & leppig, pl. 4, figs. 7–8; pl. 8, figs. 1–3. red algae family corallinaceae (coralline algae) genus ethelia (pfender) ethelia album (pfender) pl. iv, figs. 10, 14 1938 ethelia album (pfender), p. 303, pl. 19, figs. 1–5. 5. summary and conclusions the present study is an attempt to throw more light on the stratigraphy of the southern galala plateau. this is a very detailed stratigraphic analysis both lithostratigraphically and biostratigraphically, and has some additional chronostratigraphic implications. the exposed rocks in the area west of the saint anthony monastery have not been previously studied, except for inclusion in some general publications on the southern galala plateau. the stratigraphic analysis is based on a detailed micropalaeontologic investigation of some upper cretaceous rocks exposed in the area west of the saint anthony monastery, southern galala, eastern desert, egypt. two stratigraphic sections were described, measured and sampled – the umm khayshar section (139 m thick, 49 samples) and the umm damaranah section (197 m thick, 42 samples). the stratigraphic studies subdivided the campanian–early eocene rocks exposed into three rock units. these units are (from base to top): the gebel thelmet formation (campanian), sudr chalk (maastrichtian) and southern galala formation (palaeocene–early eocene). the distribution of the identified foraminifera either small or large with some macrofos127ismail et al.: campanian–early eocene stratigraphy of the southern galala plateau... sil horizons were the main basis for the biostratigraphic studies. the occurrence of orbitoides media (archiac)– omphalocyclus macropora (lamarck) in the gebel thelmet formation, in addition to a reasonable number of small foraminifera in the umm khayshar section, defines the late campanian–early maastrichtian period here. this larger foraminiferal horizon is overlain by chalky deposits (sudr chalk of ghorab, 1961) yielding numerous planktonic foraminiferal species. among these species, the globotruncana aegyptiaca delineates the early–middle maastrichtian, in addition to exogyra overwegi boch and exogyra cornuarietis coquand (middle maastrichtian). the associated foraminiferal assemblage is: pseudoclavulina maqfiensis le roy, dentalina colei cushman & dusenbury, dentalina communis (d’orbigny), lenticulina muensteri (roemer), heterohelix globulosa (ehrenberg), heterohelix moremani (cushman), heterohelix striata (cushman), globigerinelloides prairiehillensis pessagno, globigerinelloides subcarinata (bronnimann), hedbergella holmedlensis olsson, globotruncana aegyptiaca nakkady, globotruncana bulloides volger, globotruncana linneana (d’orbigny), contusotruncana fornicata (plummer), globotruncanita stuarti (de lapparent), archaeoglobigerina blowi pessagno, rugoglobigerina macrocephala bronnimann, rugoglobigerina rugosa (plummer), bulimina kickapooensis cole, bulimina reussi morrow, bulimina sp., cibicides praecursorius (schwager), anomalina umbonifera (schwager), anomalinoides nakkady said & kenawy, anomalinoides sinaensis said & kenawy, heterolepa hispaiolae (bermudez) and gyroidina cf. subangulata (plummer). the gebel thelmet formation represents a continuation of the transgression and deposition in an open marine environment in its lower part, and coastal marine to near shore shelf seas in its upper part. the sudr chalk begins with deposition under an open marine environment and ended with sedimentation in a shallow marine environment. the southern galala formation represents deposition in a shallow marine environment (coastal marine). the shallow water carbonates within the palaeogene stratigraphy of the southern galala plateau yield several larger foraminiferal species of stratigraphic significance. a few beds also contain some planktonic foraminifera, which aids determination of the stratigraphic position of the larger foraminifera. glomalveolina dachlensis was recorded in the morozovella angulata zone. this indicates that the stratigraphic level of glomalveolina dachlensis is possibly early–middle palaeocene. furthermore, the occurrence of the algae ethelia album (pfender) and neomeris plagnensis deloffre supports the suggested age for glomalveolina dachlensis (pers. comm. with professor j. kuss). most of the planktonic foraminifera were poorly preserved which makes it difficult to delineate the palaeocene/eocene boundary. the early eocene rocks contain nummulites cf. subramondi. in the southern galala, the early eocene rocks represent a remarkable sequence that unconformably overlie the palaeocene rocks and form a steep and vertical inaccessible scarp. acknowledgement the authors are deeply indebted to professor j. kuss, department of geology and geochronology, university of bremen, germany, for identification of the recorded algae and reading the manuscript. 6. references abdallah, a.m. & eissa, r. (1971): the campanian rocks of the southern galala, a.r.e.– bull. fac. cairo univ., 44, 259–270. abdallah, a.m., el sharkawi, m.a. & marzouk, a. (1971): geology of mersa thelmet area, southern galala, eastern desert, a. r. e.– bull. fac. sci. cairo univ., 47, 271–280. andreieff, p. & marionnaud, j.m. (1973): le senonien superieur des falaises de la gironde.– bulletin du bureau de recherches geologiques et minieres, ser. 2 (1), 39–44. archiac, e.j.a. (1837): memoire sur la formation cretacee du sud-ouest de la france.– memoires de la societe geologique de france, ser. 12, 157–192. awad, g.h. & abdallah, a.m. (1966): upper cretaceous in southern galala, eastern desert with emphasis on neighboring areas.– jour. geol. u. r. e., 10, 125–142. berggren, w.a. & pearson, p.n. (2005): a revised tropical to subtropical paleogene planktonic foraminifera zonation.– journal of foraminiferal research, 35/4, 279– 298. berggren, w.a., kent, d.v., swisher c.c. & aubry, m. (1995): a revised cenozoic geochronology and chronostratigraphy.– in: berggren, w.a., kent, d.v., aubry, m. & hardenbol, j. (eds.): geochronology, time scales and global stratigraphic correlation. special publication of society for sedimentary geology. tulsa, 129–212. bolli, h.m. (1957): the genera globigerina and globorotalia in the paleocene–lower eocene lizard springs formation of trinidad b. w. i.– united states nat. museum bull. 215, 61–82. bolli, h.m., beckmann, j.p. & saunders, j.b. (1994): benthic foraminiferal biostratigraphy of the south caribbean region.– cambridge university press, cambridge, 408 p. bronnimann, p. (1952): globigerinidae from the upper cretaceous (cenomanian–maastrichtian) of trinidad, b. w. i.– bull. am. paleont., 34, 5–71. caron, m. (1985): cretaceous planktonic foraminifera.– in: bolli, h.m., saunders, j.b. & perch nielsen, 128 geologia croatica 60/2 k. (eds.): plankton stratigraphy. cambridge univ. press, cambridge, 17–86. cushman, j.a. (1938): cretaceous species of guembelina and related generas.– contributions from cushman laboratory of foraminiferal research, 14/1, 2–28. cuvilier, c. & pomerol, c. (1986): stratigraphy of the paleogene.– bull. soc. geol. france, 11/2, 255–265. de la harpe, ph. (1883): monographie der in aegypten und der libyschen wüste vorkommenden nummuliten.– palaeontographica, 30, 155–216. deloffre, r., poignant, a.f. & teherani, k. (1977): algues calcaires de l’albo–aptien au paleocene de l’iran central.– bull. centre. rech. explor. prod. elf. aquitaine, 1, 29–57. douville, h. (1920): revision des orbitoides, i. partie: orbitoides cretaces et genre omphalocyclus.– bull. soc. geol. france, 4, 20, 209–232. ehrenberg, c.g. (1840): die bildung der europaischen, libischen und arabischen kreidemergels aus mikroskopischen organismen.– kryizeinest kultar preussiche akademic wissenschaften, berlin, abhandlungen, 59– 147. farag, i.a.m. (1954): on the occurrence of lias in egypt.– egypt. j. geol., 1, 1–33. faujas de saint fond, b. (1802): naturlijke histoire van den st. pieters berg bij maastricht. amsterdam, netherlands.– jour. allart, 340 p. finlay, h.j. (1947): new zealand foraminifera key species in stratigraphy, no. 5, n.z.– j. sci technol., section b, 28, 259–292. ghorab, m.a. (1961): abnormal stratigraphic features in ras gharib oilfield.– third arab. petrol. cong., alexandria, 10 p. goharian, f. (1971): etude micropaleontologique du campanien type des charentes.– revue de micropaleontologie, 14, 20–34. gorsel, j.t. van (1973): lepidorbitoides from the campanian type region.– koninklijke nederlandse akademie van wetenschappen amesterdam, proceedings, b. 76, 260–272. hanzawa, s. (1962): upper cretaceous and tertiary threelayered larger foraminifera and their allid forma.– micropaleontology, 8/2, 129–186. henson, f.r.s. (1948): larger imperforate foraminifera of south-western asia, families lituolidae, orbitolinidae and meandropsinidae.– british museum (natural history), london, 11, 1–127 hottinger, l. (1958): geologie du mont cayla (aude, aquitaine orientale).– eclogae geol. helv., 51/2, 437– 451. hottinger, l. (1960): recherches sur les alveolines du paleocene et de l’eocene.– mem. suisses paleont., 75, 243 p. hottinger, l. (1969): the foraminifera genus yaberinella vaughan 1928, remarks on its species and on its systematic position.– eclogae geol. helv., 62, 745–749. hottinger, l. & drobne, k. (1980): early tertiary conical imperforate foraminifera.– razprave sazu, 22, 188–276. ismail, a.a. (1992): maastrichtian–early eocene benthonic foraminiferal biostratigraphy and paleoecology of west central sinai, egypt.– m. e. r. c. ain shams univ., earth sci. ser., 6, 139–150. ismail, a.a. & boukhary, m. (2001): campanian larger foraminifera of gebel thelmet formation (stratotype), southern galala, eastern desert, egypt.– revue paleobiol., 20/1, 77–90. keheila, e.a. (2000): stratigraphy of the lower eocene succession in the northern and southern galala plateaux, eastern desert, egypt.– bull. fac. sci. assiut univ., 29(1– f), 27–54. krumbeck, l. (1906): beitrage zur geologie and paleontologie von tripolis.– paleontogr., 53, 51–136. kuss, j. (1986): facies development of upper cretaceous– lower tertiary sediments from the monestery of saint anthony/eastern desert, egypt.– facies, 15, 177–194. kuss, j. & leppig, u. (1989): the early tertiary (middle–late paleocene) limestones from western gulf of suez, egypt.– n. jb. geol. palaont. abh., 177/3, 289–332. lambert, b. (1980): etude de la nannoflore calcaire du campanien charetes.– cahiers de micropaleontologie, 3, 39–55. loeblich, a.r. & tappan, h. (1988): foraminiferal genera and their classification.– treatise on invertebrate paleontology. vn nostrand reinhold company, 970 p. luger, p. (1985): stratigraphie der marinen oberkreide und des alttertiars in südwestlichen obernil–bechen (swagypten) under besonderer berucksichtigung der micropaleontologie, palökologie und paleogeographie.– berliner geowiss. abh., a (63), 151 p. mazhar, a., enany, n. & el bagouri, y. (1979): contribution to the cretaceous–early tertiary stratigraphy of el galala el qibliya plateau.– annals geol. surv. egypt., 9, 377–387. nakkady, s.e. (1950): a new foraminiferal fauna from the esna shales and upper cretaceous chalks of egypt.– jour. paleont., 24, 675–692. neumann, m. (1958): revision des orbitoides du cretace et de l’eocene en aquitaine occidentale.– memoires de la societe geologique de france, n ser., 1–174. neumann, m. (1967): manuel de micropaeontologie des foraminiferes (systematique – stratigraphie) i. generalities, systematique: saccamminidae a’ ataxophragmiidae.– gauthier–villers, paris, 298 p. olsson, r.k. (1964): late cretaceous planktonic foraminifera from new jersey and delaware.– micropaleontology, 10/12, 157–188. olsson, r.k., hemleben, c., berggren, w.a. & huber, b.t. (1999): atlas of paleocene planktonic foraminifera.– smithsonian contributions to paleoecology, 85, 252 p. omara, s. (1956): new foraminifera from the cenomanian of sinai, egypt.– jour. pal., 30/4, 883–890. 129ismail et al.: campanian–early eocene stratigraphy of the southern galala plateau... pessagno, e.a. (1967): upper cretaceous planktonic foraminifera from the western gulf coastal plain.– palaeontolographica americana, 5 (37), 245–445. pfender, j. (1938): les foraminiferes du valanginien provencal.– bulletin de la societe geologique de france, ser. 5/8, 231–242. platel, j.p. (1977): le campanien stratotypique dans le synclinal de saintes (charente): lithostratigraphie, geomorphologie et biozonation.– bull. bur. rech. geol. mini., ser. 2 (14), 261–276. plummer, h.j. (1926): foraminifera from the midway formation in texas.– bull. texas univ. bur. econ. geol., 2644, 1–206. postuma, j. (1971): manual of planktonic foraminifera.– elsevier publishing co., amsterdam, 420 p. renz, o. (1937): uber ein maestrichtien–cenomanien vorkommen bei alfermee am bielersee, mit einer nachschrift von a. buxtorf.– eclogae geol. helv., 29/2, 545–566. said, r. & barakat, m.g. (1957): lower cretaceous foraminifera from khashm el mistan, northern sinai, egypt.– micropaleontology, 3/1, 39–47. said, r. & kenawy, a. (1956): upper cretaceous–lower tertiary foraminifera from northern sinai.– micropaleontology, 2, 105–173. schaub, h. (1951): stratigraphie und paläontologie des schlierenflysches mit besonderer berücksichtigung der paleocaenen und untereocaenen nummuliten und assilinen.– schweiz. paläont. abh. (mem. suisses paléont.), 68, 1–222. schaub, h. (1981): nummulites et assilines de la téthys paléogéne. taxionomie, phylogenése et biostratigraphie.– schweiz. paläont. abh., 104, 1–236. scheibner, c., kuss, j. & marzouk, a.m. (2000): slope sediments of paleocene ramp-to-basin transition in ne egypt.– int. journ. earth sciences, 88, 708–724. scheibner, c., marzouk, a.m. & kuss, j. (2001): maastrichtian–early eocene litho–biostratigraphy and paleoecology of the northern gulf of suez region, egypt.– jour. african earth sciences, 32, 223–255. schlumberger, c. (1901): premiere note sur les orbitoides.– bull. soc. geol. france, ser. 4, 1–56. schwager, c. (1883): die foraminiferen aus dem eocaenablegerungen der libyschen wuste und agyptens.– paleontographica, 30, 81–153. selima, a.m. & askalany, m.m. (1996): stratigraphy and depositional environment of the upper cretaceous– lower tertiary sequence, around wadi askhar el qebly south galala, gulf of suez, egypt.– bull. fac. sci. assiut univ., 25(2–f), 87–106. seronie-vivien, m. (1972): contribution a l’etude du senonien en aquitaine septentrionale. ses stratotypes: coniacien, santonien, campanien.– les stratotypes franqais, 2, edition du centre nationale de la recherche scientifique, paris, 195 p. sigal, j. (1977): essai de zonation du cretace mediterranean a paide des foraminiferees planctoniques.– geologie mediterraneenne, 4, 99–108. sliter, w.v. (1968): upper cretaceous foraminifera from southern california and northwestern baja california, mexico.– univ. kansas paleontol. contrib., 49, 1–141. subbotina, n.n. (1947): foraminifers of the danian and paleogene deposits of the northern caucasus.– in: microfauna of the cauasus emba region and central asia. trudy vnigri, 39–160. toumarkine, m. & luterbacher, h.p. (1985): paleocene and eocene planktonic foraminifera.– in: bolli, h.m., saunders, j.b. & perch–nielsen, k. (eds.): plankton stratigraphy. cambridge earth science series, 87–154. van hinte, j.e. (1965): an approach to orbitoides.– koninklijke nederlandse akademie van wetenschappen amesterdam, proceedings, b. 68, 57–71. volger, j. (1941): ober-jura und kreide von misol (niederlandisch–ostindien).– palaeontolographica, 4 (suppl.), 243–293. white, m.p. (1928): some index foraminifera from the tampico embayment area of mexico.– jour. of paleontology, 2/3, 177–215. manuscript received february 14, 2007. revised manuscript accepted november 23, 2007. 130 geologia croatica 60/2 plate i 1 heterohelix glabrans (cushman), sample uk 75, gebel thelmet formation, campanian (deposit no. uk 75 1). 2 heterohelix striata (ehrenberg), sample uk 80, sudr chalk, maastrichtian (deposit no. uk 80 6). 3 globigerinelloides prairiehillensis pessagno, ventral view, sample uk 80, sudr chalk, maastrichtian (deposit no. uk 80 7). 4 globigerinelloides subcarinata (bronnimann), ventral view, sample uk 80, sudr chalk, maastrichtian (deposit no. uk 80 8). 5 hedbergella holmdelensis olsson, ventral view, sample uk 80, sudr chalk, maastrichtian (deposit no. uk 80 9). 6 globotruncana aegyptiaca nakkady, ventral view, sample uk 80, sudr chalk, maastrichtian (deposit no. uk 80 10). 7 globotruncana bulloides volger, ventral view, sample uk 80, sudr chalk, maastrichtian (deposit no. uk 80 13). 8 archaeoglobigerina blowi pessagno, ventral view, sample uk 80, sudr chalk, maastrichtian (deposit no. uk 80 16). 9 rugoglobigerina macrocephala bronnimann, ventral view, sample uk 80, sudr chalk, maastrichtian (deposit no. uk 80 17). 10 rugoglobigerina rugosa (plummer), ventral view, sample uk 80, sudr chalk, maastrichtian (deposit no. uk 80 18). 131 2 1 3 4 5 6 7 8 9 10 50 μm 50 μm 50 μm 50 μm 50 μm 50 μm 50 μm 50 μm 50 μm 50 μm ismail et al. plate i 132 geologia croatica 60/2 plate ii 1–3 planorotalites pseudomenardii (bolli), 1 – ventral view, sample ud 36, southern galala formation, middle palaeocene (deposit no. ud 36 1), 2 – dorsal view, sample ud 39, southern galala formation, late palaeocene (deposit no. ud 39 1), 3 – side view, sample ud 40, southern galala formation, late palaeocene (deposit no. ud 40 1). 4 acarinina primitiva (finlay), ventral view, sample ud 38, southern galala formation, late palaeocene (deposit no. ud 38 1). 5, 6 morozovella angulata (white), 5 – dorsal view, sample ud 34, southern galala formation, middle palaeocene (deposit no. ud 34 1), 6 – ventral view, sample ud 39, southern galala formation, late palaeocene (deposit no. ud 39 2). 7 morozovella cf. conicotruncata (subbotina), ventral view, sample ud 34, southern galala formation, middle palaeocene (deposit no. ud 34 2). 8 morozovella trinidadensis (bolli), ventral view, sample ud 37, southern galala formation, late palaeocene (deposit no. ud 37 2). 9 morozovella uncinata (bolli), ventral view, sample ud 37, southern galala formation, late palaeocene (deposit no. ud 37 3). 10, 11 globigerina triloculinoides plummer, 10 – ventral view, sample ud 39, southern galala formation, late palaeocene (deposit no. ud 39 3), 11 – dorsal view, sample ud 39, southern galala formation, late palaeocene (deposit no. ud 39 4). 133 1 50 μm 50 μm 50 μm 50 μm 50 μm 50 μm 50 μm 50 μm 50 μm 50 μm 50 μm 2 3 4 5 6 7 8 9 10 11 ismail et al. plate ii 134 geologia croatica 60/2 plate iii 1–4, 6, 7, 11 orbitoides media (archiac), 1–3 – external view, specimens from sample ud2, gebel thelmet formation, campanian (deposit no. ud 2 1, 2, 3), 4 – axial section, specimen from sample ud 3, gebel thelmet formation, campanian (deposit no. ud 3 1), 6–7 – axial section, specimens from sample uk66, gebel thelmet formation, campanian (deposit no. uk 66 1, 2), 11 – protochonch of orbitoides media (archiac), sample uk66, gebel thelmet formation, campanian (deposit no. uk 66 3). 5, 8–10 omphalocyclus macropora (lamarck), 5 – axial section, specimen from sample uk 67, gebel thelmet formation, campanian (deposit no. uk 67 1), 8 – axial section, specimen from sample uk 71, gebel thelmet formation, campanian (deposit no. uk 71 1), 9 – axial section, specimen from sample ud 2, gebel thelmet formation, campanian (deposit no. ud 2 5), 10 – equatorial section, specimen from sample uk 67, gebel thelmet formation, campanian (deposit no. ud 67 2). 135 1 1 mm 2 3 1 mm 1 mm 1 mm 1 mm1 mm 4 7 5 6 8 9 1 mm 1 mm 1 mm 1 mm 0.5 mm 10 11 ismail et al. plate iii 136 geologia croatica 60/2 plate iv 1, 2 glomalveolina dachelensis (schwager), sample ud 22, southern galala formation, early?/middle palaeocene (deposit no. ud 22 1, 2). 3 nummulites cf. subramondi de la harpe, axial section, specimen from sample uk 104, southern galala formation, ypresian (deposit no. uk 104 1). 4–6 miscellanea rhomboidea kuss & leppig, sample ud 22, southern galala formation, early?/middle palaeocene (deposit no. ud 22 3,4,5). 7 fabularia zitteli hottinger, sample ud 42, southern galala formation, ypresian (deposit no. ud 42 1). 8–9, 12 alveolina pasticillata (schwager), 8 – near axial section, sample uk 104, southern galala formation, ypresian (deposit no. uk 104 2), 9, 12 – near equatorial section, sample uk 104, southern galala formation, ypresian (deposit no. uk 104 3, 4). 11 fallotella (fallotella) kochanskae persica hottinger & drobne, sample sgy 22, southern galala formation, early?/middle palaeocene (deposit no. ud 22 6). 10, 14 ethelia album (pfender), sample uk 104, southern galala formation, ypresian (deposit no. uk 104 5,6). 13 neomeris plagnensis deloffre, sample ud 22, southern galala formation, early?/middle palaeocene (deposit no. ud 22 7). 137 1 1 mm 3 2 5 7 8 9 6 4 10 11 12 13 14 ismail et al. plate iv 138 geologia croatica 60/2 geo.cro.2-3-61-kb.pdf 345 � roman aubrecht1, tomáš lánczos2, branislav šmída3, charles brewer-carías4, federico mayoral4, ján schlögl1, marek audy5, lukáš vlček6, ľubomír kováčik7 and miloš gregor8 ab stra ct caves in arenites of the roraima group in venezuela have been explored on the chimantá and roraima plateaus (tepuis). geological and geomorphological research showed that the most feasible method of caves genesis was the winnowing and erosion of unlithifi ed or poorly lithifi ed arenites. the unlithifi ed arenitic beds were isolated by wellcemented overlying and underlying rocks. there is a sharp contrast between these well-lithifi ed rocks and the loose sands which form the poorly lithifi ed to unlithifi ed beds. they are only penetrated by well lithifi ed pillars originated by vertical fi nger fl ow of the diagenetic fl uids from the overlying beds. such fi nger fl ow is only typical for loose sands and soils where there is a sharp difference in hydraulic conductivity. the pillars exhibit no signs of further dissolution. the caves form when the fl owing water accesses the poorly lithifi ed beds through clefts. collapse of several superimposed winnowed-horizons can create huge subterranean spaces. futher upward propagation of the collapses can lead to large collapse zones which are commonly observed on the tepuis. dissolution is also present but it probably plays neither a trigger role, nor a volumetrically important role in the cave-forming processes. the strongest dissolution/reprecipitation agent is condensed air moisture which is most likely the main agent contributing to growth of siliceous speleothems. as such, it can be active only after, but not before the cave is created. siliceous speleothems are mostly microbialites except for some normal stalactites, cobweb stalactites and fl owstones which are formed inorganically. they consist of two main types: 1. fi ne-laminated columnar stromatolite formed by silicifi ed fi lamentous microbes (either heterotrophic fi lamentous bacteria or cyanobacteria) and 2. a porous peloidal stromatolite formed by nostoc-type cyanobacteria. the initial stages of encrusted shrubs and mats of microbes were observed, too, but the surrounding arenitic substrate was intact. this is strong evidence for the microbial mediation of silica precipitation. keywor ds: speleology, tepuis, venzuela, sandstone caves, siliceous speleothems, microbialites, cyanobacteria, stromatolites, hydrogeochemistry. 1 department of geology and paleontology, faculty of natural sciences, comenius university, mlynská dolina – g, sk-842 15 bratislava, slovakia; (aubrecht@fns.uniba.sk; schlogl@fns.uniba.sk) 2 department of geochemistry, faculty of natural sciences, comenius university, mlynská dolina – g, sk-842 15 bratislava, slovakia; (lanczos@t-zones.sk) 3 slovak speleological society, čajkovského 40, 917 08 trnava, slovakia; (brano.smida@gmail.com) 4 fundación explora, caracas, venezuela; (charlesbrewer@cantv.net, fmayoralp@cantv.net) 5 czech speleological society, tyršova 332, cz-679 06 jedovnice, czech republic; (audy@speleo.cz) 6 slovak caves administration, hodžova 11, sk-031 01 liptovský mikuláš, slovakia; (vlcek@ssj.sk) 7 department of botany, faculty of natural sciences, comenius university, révová 39, sk-811 02 bratislava, slovakia; (kovacik@fns.uniba.sk) 8 department of mineralogy and petrology, faculty of natural sciences, comenius university, mlynská dolina – g, sk-842 15 bratislava, slovakia venezuelan sandstone caves: a new view on their genesis, hydrogeology and speleothems geologia croatica 61/2–3 345–362 3 figs. 4 pls. zagreb 2008 geologia croaticageologia croatica � geologia croatica geologia croatica 61/2–3 346 1. introduction caves are common in limestone terrains. karstic phenomena can easily evolve in limestone or other rock materials with good solubility, e.g. gypsum. most defi nitions of karst use dissolution as the main factor that determines the true karstic processes. solubility of silicate rocks is generally very low and caves which formed in silicate rocks are often attributed to pseudokarst, because most workers believe that mechanisms other than dissolution play the main role in their formation. tectonic phenomena (fracturing, faults, etc.) are considered as the main factors. however, in the recent past, several publications have applied the term karst to silicate caves that occur either in granites (willems et al., 2002; vidal romaní & vaqueiro rodrigues, 2007) or, more frequently, in sandstones (see the reviews in wray, 1997b, 1999). according to these authors, dissolution, although slow, is the main process that forms the caves. for sandstone rocks, the term “arenization” was introduced by martini (1979). this term involves both the dissolution of cements in the arenitic rocks, together with the subsequent erosion and winnowing of the loose sand material. if the “arenization” theory was true, most of the sandstone caves could really be attributed to karst as dissolution is considered there to be trigger process of the cave formation. the main proof that dissolution is important in silicate caves are silica speleothems which occur in most of the silicate caves. they are mostly composed of opal-a (cf. aubrecht et al., 2008), which slowly turns to opal-ct and then to microquartz (chalcedony). the question remains, whether silica dissolution is so important that the silicate caves can really be ranked among the karstic ones. initial results of several speleological and scientifi c expeditions to the venezuelan gran sabana, where large caves evolved in the sandstone plateaus called tepuis, are presented. tepuis are the key area where sandstone “karstic” phenomena can be studied and where the term “arenization” is widely used (e.g. urbani, 1986). alternative views on the genesis of sandstone caves are presented here, based on geological, geomorphological, hydrogeochemical and speleological observations. 2. geological setting and the caves studied the studied area is located in the venezuelan guayana of north ern south america (southeastern venezuela, bolivar state), in “the corner” formed by the borders of guayana to the east and brazil to the south (fig. 1). the wider area of the gran sabana is built up by rocks of guiana shield which represents the northern segment of the amazonian craton in the south america. it covers an area of nearly 900,000 km2 between the amazon and orinoco rivers (cordani et al., 1988, in voicu et al., 2001) and underlies the territory of fi ve countries (venezuela, guyana, suriname, french guiana and brazil). the tepuis are formed by the rocks of the roraima supergroup, consisting principally of sandstones derived from the trans-amazonian mountains to the north and deposited in braided, deltaic, and shallow-marine environments (reis et al., 1990, in santos et al., 2003) in a foreland basin. the supergroup mostly forms tabular plateaus, cuestas and hogbacks that abruptly rise above the palaeoproterozoic basement. its thicknesses ranges from 200 m to ~3000 m. local sedimentological studies show that depositional environments range from alluvial fans to fl uvial braided deposits plus lacustrine, aeolian, tidal, shallow-marine deposits and some shallow water turbidites (reis & yánez, 2001; santos et al., 2003), although sandy continental deposits predominate. the supergroup is composed (from the bottom to top) of the following units (formations): arai, suapi (uiramută, verde, pauré, cuquenán, quinô), uaimapué and matauí (reis & yánez, 2001). the tepuis developed mainly within the uppermost of these – the matauí formation. the best age estimate for all but the uppermost roraima supergroup is 1873 ± 3 ma, determined by u-pb analyses of zircons from a green ash-fall tuff of the uaimapué formation (santos et al., 2003). the history of discovering and documenting the sandstone caves in the tepuis began in 1971 when brewer-carías led the fi rst expedition to cerro autana (brewer, 1972, 1973, 1976; colveé, 1973). later he also led the multidisciplinary expedition that explored and discovered the abysses (simas) and caves in the sarisariñama massif (brewer, 1973; szczerban & gamba, 1973; szczerban & urbani, 1974; brewer, 1974). later, quartzite caves in auyán tepuy were documented by piccini (1995). the longest sandstone cave system, ojos de cristal was recently discovered in 2002 on the roraima tepui (šmída et al., 2003). in the same year, the volumetrically largest sandstone cave was discovered in the chimantá tepui – cueva charles brewer (šmída et al., 2005a, b). the last two caves, together with smaller caves later discovered in chimantá – cueva cañon verde, cueva de arañas and cueva bautismo del fuego are the subject of the present study. simultaneously, surface weathering phenomena have been studied on the chimantá, roraima and kukenán tepuis. 3. methods the geological and speleological observations were focused on the differential weathering of various sorts of arenites of the matauí formation on the tepui surfaces and in the caves. fi gu re 1: location of the studied table mountains. geologia croaticaroman aubrecht et al.: venezuelan sandstone caves: a new view on their genesis, hydrogeology and speleothems 347 four sites with different lithifi cation and erosion phenomena in arenites were sampled in detail for petrographic analysis (thin-sections and sem), the results of which will be published later. sampling of siliceous speleothems was equally important. a limited number of samples were collected for study by petrographic thin-sections, to prevent excessive damage to the speleothem decoration of the cave. fresh speleothem surfaces in growth position, as well as surfaces of broken speleothems (some etched by hydrofl uoric acid), were coated with a thin gold fi lm and observed in a jeol jxa 840 a scanning electron microscope, with an accelerating voltage of 5 kv. the mineralogical composition of the speleothems was determined optically and by x-ray diffraction analysis (xrd). analyses were performed with a dron-3 analyser, using cokα of the wavelength λ: 1.79021 å, fi lter fe, voltage 30 kv, intensity 15 ma, diaphragms 1;1;0.1, or cukα of the wavelength 1.54178 å, fi lter ni, voltage 40 kv, intensity 20 ma, diaphragms 1;1;0.5. speleothem surfaces were also sampled for microbiological analyses by scraping with a sterilized knife. part of the samples were fi xed in agar for further cultivation (about 20 samples – results not included); and about 40 samples were fi xed in formaldehyde (for microscopic observations only). the hydrogeochemical fi eldwork consisted of sampling, fi eld parameter measurements and colourimetric analyses. part of the samples (in 50 ml quantities) were used for colourimetric analyses performed the same day in the base camp, the next part (15 ml) was sealed in plastic containers and transported to slovakia for further determination of δ18o and δ2h. samples were fi ltered in situ using a fi lter with mesh diameter of 0.45 μm. every sample was doubled. the fi eld parameter measurements consisted of ph and electric conductivity (ec). at the beginning, acidity and alkality measurements were made by titration, but all the measured amounts were below the detection limits of these methods, therefore, this method was later abandoned. for colourimetric analyses, the merck spectroquant multy portable colourimeter was used. the following parametres were measured: fe, sio2–si, al, po4 3–p, no3–n. 4. results and interpretations 4.1. genesis of the sandstone caves in the studied caves, erosion and rockfalls are the most obvious and recent evidence of their formation rather than dissolution (pl. i, fig. 1). the sandstone beds have angular edges; the caves are full of fallen angular blocks. the signs of dissolution e.g. smooth edges of sandstone beds or bizarre patterns formed by etching (pl. i, fig. 2) are too rare to explain the recent stages of the caves evolution. however, to be ranked among karstic features, prevalence of dissolution is not required; the most important factor is its role as a trigger of cave genesis. the question then remains, what was the trigger factor, which determined how the sandstone caves in the tepuis originated and the place where a cave can be formed? observations of surface geomorphology of the tepuis and the subterranean spaces provide some clues. the sandstone surfaces of the tepuis are very bizarre, due to the very inhomogeneous lithifi cation of the proterozoic arenites, which is obvious from initial observations. this is especially visible in the places where the arenite bed forms overhang (pl. i., figs. 3–6). the overlying and underlying beds are hard, well-lithifi ed rocks, forming sandstones to quartzites (diffi cult to sample with a hammer, requiring a lot of force). however, the beds in between are only slightly lithifi ed or completely unlithifi ed, being soft sandstones to sands (it was not possible to take any lithifi ed sample for petrographic microscopic study, even digging using hands up to 30 cm below the surface). these very weakly lithifi ed beds are divided up by perpendicular pillarshaped bodies, narrower in the middle part, but widening, funnel-like towards the top and bottom, with the lower funnel usually less developed. these are again well-lithifi ed (sandstones to quartzites). this combination of overhangs and pillars forms the dramatic decoration of most of the tepuis surfaces (pl. i, figs. 7–8). the origin of these structures can be interpreted as being purely diagenetic. the mean factor infl uencing the diagenetic variability is the sediment grain size, which infl uences its hydraulic conductivity. the diagenetic fl uids most likely penetrated vertically from the overlying strata. in fi ner-grained sediments the diagenetic fl uids fi lled the intergranular spaces evenly and thus formed diagenetically well-lithifi ed beds, resistant to weathering. if a coarsegrained arenite with higher hydraulic conductivity occurred below a fi ne-grained bed, a process named “fi nger fl ow” started, i.e. the fl uid fl ow accelerates due to gravity and is divided into separate, fi nger-like fl ows. this process has been described in detail by various authors working with transport processes in the unsaturated zone of sandy aquifers and soils (e.g. bauters et al., 1999; liu et al. 1994). according to liu et al. (1994), if these fi nger fl ows are generated in originally dry sandstones they are conserved as preferential pathways for infi ltrating solutions. this is how the pillars originated in the unlithifi ed sands. the upper, narrowing downwards funnel shape of the upper part of the pillar originated from acceleration of the fl ow, until it was slowed down when it reached the less permeable bottom. this slowing-down is displayed by the reversely oriented funnel shape of the pillar bottom. the poorly lithifi ed beds form distinct horizons in the tepuis geomorphology. they can be traced and correlated laterally for long distances. the overlying and underlying beds protect the unlithifi ed sand from rainfall but they are easily eroded when accessed by water streams fl owing horizontally. when the overlying, protecting beds are weathered, broken, or dissected by clefts water can penetrate as deep as the unlithifi ed beds and a horizontal cave can form. indeed, our observations show that pillars are present in most of the caves and in their galleries, which are still in the younger stages of their evolution (pl. ii, figs. 1–2). these usually possess low ceilings and strictly keep to one distinct layer. if several superimposed winnowed horizons evolve, the second, collapse stage follows, leading to formation of much larger subterranean spaces (pl. ii, figs. 3–4). relic fi nger-fl ow pillars were also observed in the marginal, uncollapsed parts of the larger galleries (pl. ii, figs. 5–6). in the cueva charles brewer, the galleries are typically 40 metres wide, but can be much larger. geologia croatica geologia croatica 61/2–3 348 plate i 1 gran galería de los guácharos (cueva charles brewer); one of the top ten largest natural subterranean spaces in the world. in its latest evolution it has been shaped by rockfalls which obscur the initial stages of formation. 2 dissolution pits on an arenitic block in the cueva charles brewer. the dissolution was most likely mediated by microbes. 3–5 overhanging arenitic beds showing diff erential weathering due to variable lithifi cation: o – overlying bed strongly lithifi ed quartzite, u – underlying bed of the same lithology, p – strongly lithifi ed quartzite pillars formed by descending fi nger fl ows of diagenetic fl uids, s – poorly lithifi ed to unlithifi ed sands, h – honeycomb-like weathering of the sandstones. 6 two superimposed poorly lithifi ed horizons (pale grey) separated by well-lithifi ed quartzites (dark). increased view of the same as fi g. 3. 7–8 spectacular surface features of monte roraima, displaying rows of fi nger-fl ow pillars. geologia croaticaroman aubrecht et al.: venezuelan sandstone caves: a new view on their genesis, hydrogeology and speleothems 349 geologia croatica geologia croatica 61/2–3 350 plate ii 1–2 beautifully preserved fi nger-fl ow pillars in cueva cañon verde (chimantá massif ) – an initial stage of the caveforming process. the unlithifi ed sand has been winnowed; only strongly lithifi ed quartzitic elements remaining. note the smooth surface of the ceiling, fl oor and pillars, free of any signs of dissolution, indicating that there was a strong contrast between the lithifi cation of both constituents. 3–4 galleries of the cueva de arañas showing progressive evolution by collapse of the fl oors between two superimposed winnowed horizons forming a larger cave. the fi nger-fl ow pillars are preserved at the margins of the galleries. 5–6 small-scale fi nger-fl ow pillars preserved at the margins of a larger, highly-developed cave (ojos de cristal system, roraima). geologia croaticaroman aubrecht et al.: venezuelan sandstone caves: a new view on their genesis, hydrogeology and speleothems 351 geologia croatica geologia croatica 61/2–3 352 the largest chamber found in the cave, gran galería karen y fanny, is 40 metres in height, more than 355 metres in length, and 70 metres wide: a volume of about 400,000 cubic metres. final stages can lead to huge collapses, which are observable on the tepui surfaces (pl. iii, figs. 1–2). one of the largest collapse zones separates the akopán tepui from the churí tepui in the chimantá massif (pl. iii, fig. 3). the whole zone is sunken and the sandstone mass is dissected into large blocks which are variously inclined. obviously, they were “undercut” by winnowing of the unlithifi ed sand layers and then collapsed. any other process, like dissolution, arenization (dissolution of cements and release of the sand grains), or weathering, were unable to create such a huge collapse zone. the linear course of this zone betrays the fact that it is related to fault tectonic activity (cf. briceño & schubert, 1992), but it could not solely be responsible for the collapse. it is more likely that it just triggered the collapse by enabling drainage of the fl owing water and transport of the solid material from the unlithifi ed strata. on the basis of these observations, winnowing of the unlithifi ed or weakly lithifi ed sands, not only plays the triggering role in formation of the sandstone caves in tepuis, but it also infl uences their subsequent evolution. although dissolution also occurs there, (as witnessed by the presence of numerous siliceous speleothems), it has a subordinate role as a cave-forming process. 4.2. hydrogeochemistry of the caves water samples were taken from underground streams in caves, as well as from streams, ponds, swamps and springs on the surface. the sampling and fi eld analyses were performed in three campaigns, following the three periods of the expedition. the fi rst campaign performed on the top of the chimantá massif, the second inside the cueva charles brewer and the third on the surface and caves of monte roraima. detailed information about the analyses and results is given in lánczos et al. (2007). although the extent of the measured parametres was restricted due to the logistics, some conclusions about processes controlling the chemical composition of the water can be presented. acidity was only successfully measured in samples taken on the surface of the chimantá massif, but other samples are supposed to have very similar ph values. this assumption is supported by the ph values from 3.8–6.5 reported by mechhia & piccini (1999) based on sampling on the auyan tepui. the low ph values are the result of rainwater interaction with the quartzite rock which does not cause signifi cant h+ cation consumption. the other factor preserving low ph could be the presence of organic acids also indicated by the yellowish colour of the waters on tepuis and carbonic acid originating from decaying organic material in swamps and jungles on the surface of the table mountains. slightly higher ph values in two samples taken in small swamp ponds (5.48 and 5.64) were presumably caused by carbon dioxide exsolution in the swamp ponds heated by the sun during daytime. variations of ec values and sio2 concentrations are apparently controlled by water-rock interactions as well as evaporation-precipitation processes. from the ec – sio2–si relationship some differences in values and their ranges are ap parent between samples taken on the chimantá massif and on the monte roraima (fig. 2). the extent of the ec values is much narrower but the values are slightly higher in the chimantá samples than in the roraima samples. however, the sio2–si concentrations are slightly higher in the roraima samples. one of the explanations of the higher ec values of the chimantá samples could be a higher concentration of ions as a consequence of rainwater evaporation due to greater average temperatures and probably also less precipitation in comparison with roraima as a consequence of their different altitudes. the chimantá massif is about 400 m lower (the highest point is approx 2500 m a.s.l., the sample locations are approx. 2200–2300 m a.s.l.) than roraima (more than 2700 m a.s.l.). these differences are more notable in the case of the underground streams. all the samples except one taken in the cueva charles brewer have the same ec values (20 μs/cm); the sio2–si concentrations are from 0.2–0.23 mg/l, while the roraima underground stream samples show ec values from 10–18 μs/cm and the sio2–si concentrations from 0.73–1.31 mg/l. the explanation of this difference is apparently the varying cave and underground stream morphology. the cueva charles brewer is a straight 4.5 km long cave with a stream of high current velocity, with a more or less u-formed and smooth riverbed. this morphology results in a relatively small water/rock contact zone, the time of the contact is also rather short and has minimum infl uence on the chemical composition of the water. the cave system of the monte roraima is rather complicated; the water fl ows in small creeks with slow current velocities, and the river bed is often covered by sand and/or gravel. samples from the repository lake of the río arabopó and the tuná deutá spring located below the examined cave system, were also included in the evaluation. a positive correlation exists between the ec values and sio2–si concentrations. the parameters in the río arabopó sample are close to the values expected for rainwater. therefore, we suppose that this lake collects rainwater from the wider drainage area and represents the water source of the cave system. the tuná deutá spring sample characteristics are placed at the opposite end of the relationship and, consequently, it may be considered as the output from the cave system. as all the sample characteristics are situated closely around the positive trend line, we assume that the sio2 concentrations and the ec values are controlled by the kinetics of sio2 dissolution. the phenomenon of corrosive precipitation can be recognized in the cueva charles brewer of the chimantá massif and the cueva de los pemones (ojos de cristal system) of monte roraima. it is displayed as extremely low ec values (6 μs/cm in the cueva charles brewer and 2 μs/cm in the cueva de los pemones), and extremely high sio2–si concentrations (3.05, or 2.3 mg/l resp.) in the samples collected from pools fed by dripping water that condensed on the cave walls. the explanation of this phenomenon is that water vapour condensing on the cave wall acts as a strongly undersaturated agent for the dissolution of different forms of sio2. the extremely low ec values are caused by the lack of dissociated salts in the water. almost the only soluble material in quartzgeologia croaticaroman aubrecht et al.: venezuelan sandstone caves: a new view on their genesis, hydrogeology and speleothems 353 ite is sio2 which, when being dissolved under the low ph conditions, exists mainly as the non-dissociated h3sio3 not contributing to the ec. therefore, the condensed water vapour can be considered as the strongest agent acting on sio2 dissolution and reprecipitation. however, as stated in the previous chapter, the dissolution plays a subordinate role in the cave formation, which is also documented by the fact that condensation of atmospheric water vapour can only occur once the cave is already developed. 4.3. genesis of siliceous speleothems caves formed in silicate rocks (including arenitic sediments) are characterized by predominantly siliceous speleothems, in which the dominant mineral is opal. unlike in carbonate speleothems, microbial mediation is much more common in the precipitation of siliceous speleothems. siliceous speleothems commonly represent small forms, rarely exceeding 2 cm in size. in all the examined caves, peculiar forms of speleothems were found (see also aubrecht et al., 2008). they have various shapes and forms and most of them bear the signs of microbial origin (pl. iii, figs. 4–6). many of the speleothems are reminiscent of classical stalactites and stalagmites known from limestone caves, but their structure and genesis are different. apart from variable shapes, the microbial speleothems show identical principal textures, corresponding to the various stages of their evolution (pl. iv, figs. 1–2). they consist of two principal zones: 1. laminated columnar stromatolite, consisting of non-porous compact opal, mostly forming the internal zones of the speleothems, 2. a highly porous zone formed of white chalk-like opal, representing the accumulation of microbial peloids, mostly forming the outer zones of the speleothems. in some speleothems, both zones may alternate. the columnal stromatolite zone consists of fi nely laminated layers of pure opal, intercalated with some zones of fi lamentous microbialite, with thin fi laments oriented in the direction of stromatolite growth. sem study of the etched surfaces of the columnal stromatolite showed that it mostly consists of concentric laminae, formed by dense parallel tubes representing the casts of fi lamentous microbes (pl. iv, fig. 3). the microbes are most similar to fi lamentous cyanobacteria from the order oscillatoriales (golubic, 1976). in other plac es, irregular, larger-scale, double-layered cross-sections of microbe tubes occur (pl. iv, fig. 4). they resemble casts after cyanobacterial cells of the genus cyanostylon or entophysalis (golubic, 1976). the zone of peloidal microbialites consists of elongated (mostly ovoid) peloids of relatively uniform shape. they are densely packed, arranged in concentric laminae (pl. iv, fig. 5). the size of the peloids varies from 0.1 to about 0.3 mm. microscopic study revealed that the peloids are formed by nostoc-type cyanobacteria (pl. iv, figs. 6–7). fungal hyphae, metazoan and plant remains also subordinately contribute to speleothem construction. in many places, initial colonization of the surface by nostoc-type cyanobacteria was observed, forming mats and shrubs covering the underlying arenites (pl. iv, fig. 8). the microbial fi laments are commonly encrusted by white silica, whereas the surrounding arenites are intact. this is strong evidence that the microbes were not only passively encrusted by silica but the encrustation was microbially mediated, either by their metabolism, or by changing physicochemical conditions. this phenomenon is common in limestones but has not previously been evident for siliceous microbialites. some speleothems, e.g. the cobweb stalactites (aubrecht et al., 2008) represent mostly inorganic precipitates, encrusting various structures, such as spider threads. there are also large inorganically precipitated stalactites (pl. iv, fig. 9) and fl owstones. comparing the size of the speleothems from various caves, there seems to be a dependent relationship between cave and speleothem sizes. cueva charles brewer hosts the largest recorded silica speleothems (up to several dm in size) whereas those in other caves were smaller (cm to dm size). fi gu re 2: comparison of ec and sio2–si concentrations and relationships in water samples taken from the chimantá massif and monte roraima. abbreviations in the legends: cchb-p – cueva charles brewer – corrosive precipitation, cchb – cueva charles brewer, cbdf – cueva de bautismo del fuego, cdlp-p – cueva de los pemones – corrosive precipitation, cdlp – cueva de los pemones, codc – cueva ojos de cristal, td – spring tuná deutá, ra – río arabopó river. geologia croatica geologia croatica 61/2–3 354 plate iii 1 gradual cave collapses can penetrate as high as the surface. large collapse zone on monte roraima (brazil part, close to the venezuela/brazil/guyana border stone – triple point). finger-fl ow pillars are still visible under the overhangs. 2 a similar large collapse which formed the famous lake gladys (guyana part of roraima). 3 large collapse zone between two tepuis of the chimantá massif – churí and akopán. this collapse zone was probably also infl uenced by winnowing of poorly lithifi ed sediments. 4 large microbial speleothem forms called “champignons” are frequently more than 30 cm in size. 5 erect, stalagmite-like microbial speleothems called “muñecos” (dolls) which are from 10 to 15 cm high. 6 white “ice-cream”-like microbial speleothems which are up to 20 cm high (all speleothems fi gured in this plate are from the cueva charles brewer). geologia croaticaroman aubrecht et al.: venezuelan sandstone caves: a new view on their genesis, hydrogeology and speleothems 355 geologia croatica geologia croatica 61/2–3 356 plate iv 1, 2 slabs of “muñeco” (1) and “champignon” (2) from cueva charles brewer showing the common principal inner structure of all the erect speleothem forms, consisting of the columnal stromatolite (c) forming mostly the inner zones, covered by white, chalk-like peloidal layer (p). the scale is valid for both pictures. 3 etched columnal stromatolite showing longitudinal cross-sections of the encrusted mat of fi lamentous microbes. on the inner sides of some tubes there are remains of regular septae (arrow), indicating that the fi laments were sectioned. 4 irregular double-layered cross-sections of tubes likely representing casts after microbes similar to cyanobacteria cyanostylon or entophysalis. 5 concentric laminae of peloids in the peloidal zone. 6 peloids from the outer, less encrusted part of the “champignon”. these are obviously formed by short chains of microbial cells. 7 some larger cells (arrow), most likely representing heterocytes – a determining feature of the order nostocales. 8 silica-encrusted shrubs forming an initial mat of nostoc-type microbes on the quartzite substrate. the substrate is not encrusted by silica which indicates microbial mediation of silica precipitation (cueva cańon verde). picture width = 5cm. 9 inorganically precipitated silica stalactites also contribute to the cave decoration (gran galería karen y fanny, cueva charles brewer). geologia croaticaroman aubrecht et al.: venezuelan sandstone caves: a new view on their genesis, hydrogeology and speleothems 357 geologia croatica geologia croatica 61/2–3 358 5. discussion 5.1. cave genesis caves can only be formed in silicate rocks under special conditions. the most common are lava tubes which form by cooling and hardening of the outer parts of lava fl ows (lévillé et al., 2000; gradziński & jach, 2001). caves formed in other silicate rocks are less common, e.g. granites (willems et al., 2002) or arenites (sandstones and quartzites). whereas caves in granites are very rare, caves formed in arenites are known from several areas in the world (see the detailed review in wray, 1997a), such as south africa (martini, 1979, 2000) and australia (wray, 1997b, 1999). proterozoic arenites of the roraima group in venezuela and brazil are known to host the largest and deepest caves of this type in the world (šmída et al., 2003, 2005a, b; rasteiro, 2000). the existence of silicate caves other than lava tunnels seem to be surprising due to the very low solubility of sio2 (hill & forti, 1986; wray, 1997a, 1999). some authors (e.g. urbani, 1986; wray, 1997b) explain the origin and evolution of the quartzite karst by dissolution processes under various climatic conditions, combined with an extremely long exposure time to chemical weathering. dissolution, as a trigger process and as an important process during cave evolution is necessary for ranking the caves in arenitic rocks with karst phenomena (see the detailed review in wray, 1997b). several theories arose to explain the dissolution mechanism itself. some of these involve temporarily increased alkalinity of the ground waters due to lateritic weathering (marker, 1976), quartz hydration to opal (white et al., 1966), alteration of quartz to opal by microbes (vidal romaní & vaqueiro rodrigues, 2007) or hydrothermal alteration along fractures and bedding planes (szczerban et al., 1977). several authors (e.g. martini, 1979; urbani, 1986; briceño & schubert, 1990) prefer an explanation of karstifi cation by intergranular cement dissolution and subsequent mechanical release and winnowing of sand grains. weathering is considered to be penetrative, along the grain-to-grain contacts and bedding plains (chalcraft & pye, 1984; wray, 1997b). some researchers emphasize the infl uence of biogenic processes (etching by cyanobacteria, fungi and lichens) on weathering of the quartzite on tepuis (gorbushina et al., 2001; brehm et al., 2005). the evidence presented herein shows that dissolution is not necessarily the leading factor in cave formation in the roraima group. instead, the lack of lithifi cation of some arenitic strata plays a key role. the unlithifi ed strata were protected from massive infi ltration of diagenetic fl uids by extensive cementation of the overlying and underlying beds and their subsequent isolation. a horizontal course for most of the caves supports this assumption. although some workers, like wray (1999) expressed their opinion that dissolution is much stronger in beds with higher porosity, which is practically equivalent to a low degree of diagenesis, there are some arguments for not only a low degree of lithifi cation but also a complete lack of lithifi cation occurring in the arenites which can result in cave formation: 1. there is a strong contrast between lithifi cation of the beds prone to erosion and sand winnowing on one side and the surrounding strata and quartzite pillars (cemented by vertical fi nger-fl ow of diagenetic fl uids) on the other. this assumes that from any dissolution prior to winnowing and erosion, dissolving fl uids should have only fl own horizontally and the fl uid fl ow should have been limited by the strongly lithifi ed overlying and underlying beds. this horizontal movement would, however, have had to leave some traces (such as horizontal grooves). the dissolution would not leave perfectly clean spaces but, instead, bizzare swarms and nests of residual well-lithifi ed portions of arenites should be expected to fi ll the space. only rare cases of honeycomb-like weathering were observed in the poorly lithifi ed strata (pl. i, fi g. 3). also the pillars would have more bizarre surfaces, and not be perfectly smooth. our observations indicate the opposite. the quartzite pillars are often perfectly smooth, displaying only the vertical movement of fi nger fl ow. even when completely denuded in the caves, no horizontal grooves or any other such signs are visible. very few dissolution marks are also visible on the ceilings and fl oors of such caves. 2. any attempt to explain a secondary origin of the pillars (after dissolution and arenization) would make the diagenetic history much more complex. this way, the overlying and underlying beds should be still permeable enough to enable fl uids to migrate vertically but this is not in accordance with the facts mentioned above. 3. cueva charles brewer is most likely not the only giant subterranean space that occurs in the roraima group arenites. huge abysses in the sarisarińama plateau (szczerban & gamba, 1973; szczerban & urbani, 1974, brewer, 1974) or in the guaiquinima massif (szczerban et al., 1977) most likely originated by the collapse of huge caves. the sizes of those caves were proportional to the collapses recently observed. it is unlikely that such huge subterranean spaces could originate solely by dissolution, although it may have lasted from a longer time. 5.2. genesis of the siliceous microbial speleothems the microbial origin of many of the siliceous speleothems was recognized by previous workers (e.g. forti, 1994; vidal romaní & twidale, 1998; lévillé et al., 2000; willems et al., 2002; urbani et al., 2005), but very few of them attempted to closely describe the microbes. siliceous microbialites of much larger forms are known from hot springs and geysers (opal sinters). these also contain abundant microbial assemblages, dominated by cyanobacteria, i.e. phototrophic organisms (jones et al., 2001; konhauser et al., 2001; konhauser et al., 2003). phototrophic organisms – diatomaceans – were also found to contribute to the formation of similar speleothems in japan and the usa (kashima et al., 1987; kashima & ogawa, 1995). these speleothems, however, occurred close to the cave entrances, whereas speleothems presented in this paper came from the deepest parts of the cave. therefore, it is surprising that a considerable part of the central compact stromatolite of the speleothems was probably formed by cyanobacteria. biological investigations geologia croaticaroman aubrecht et al.: venezuelan sandstone caves: a new view on their genesis, hydrogeology and speleothems 359 fi gu re 3: schematic overview of cave genesis in the arenites of the roraima group. grey – well-lithifi ed arenites, pale – poorly lithifi ed arenites. a – initial stage with two contrasting poorly lithifi ed horizons superimposed on each other. b, c – flowing water penetrated through the vertical cleft (on the right side) and caused gradual winnowing of the poorly lithifi ed sediment. d – two eroded horizons remain empty (two superimposed initial caves), with lithifi ed pillars being the only support against collapse. e, f – gradual collapse of both stages, forming a large cave. geologia croatica geologia croatica 61/2–3 360 of the microbes of opal speleothems from similar sandstone caves on the sarisariñama plateau (cueva de los guacharos – kunicka-goldfinger, 1982), mostly showed the presence of heterotrophic microorganisms, the trophic life mode of which was adapted to the decaying excrement of bats and birds guarachos, as well as fruit remnants coming from their diet. the basis of microbe ecology in cueva charles brewer is as yet unclear. the presence of these otherwise phototrophic organisms in caves is not as surprising as it seems to be. some cyanobacteria do not withstand an excess of solar radiation that can damage their cells (vincent & roy, 1993; quesada & vincent, 1997). some of them produce protective pigments in an extracellular sheath (e.g. lyngbya estuarii produces the pigment scytonemine – kylin, 1937); others are able to protect themselves against excess light by boring into the substrate, e.g. endolithic boring cyanobacteria hormathonema and hyella (golubic, 1976). the genera fisherella and calothrix are able to change their mode of life to slow heterotrophy in complete darkness (whitton, 1987). finally, the most convincing fact is that some cyanobacteria, e.g. geitleria calcarea and scytonema julianum have been found inhabiting caves (friedmann, 1955; bourrely & depuy, 1973). it is obvious that the cyanobacteria in venezuelan caves are also adapted to a heterotrophic mode of life. the reason for the size dependence between the caves and the speleothems is as yet unclear. one of the possible explanations would be that the larger the cave is, the more siliceous material there is to undergo the dissolution/reprecipitation cycle. larger cave corridors and galleries of the cueva charles brewer have surfaces available for condensation of water vapour that are several times larger than other caves. such condensation plays the most important role in the cycle of speleothem formation. 6. conclusions 1. the main factor in cave formation in the arenites of the roraima group is the presence of poorly lithifi ed to completely unlithifi ed bodies within the arenite complexes, which are prone to relatively rapid winnowing and erosion when accessed by fl owing waters (fig. 3). quartz dissolution also occurs, but it plays a subordinate role in the cave formation. however, it is not yet clear if these facts can also be applied to other caves formed in arenites elsewhere in the world. 2. the low ph values of the water samples are caused by the low neutralization capacity of the quartzite rocks as well as the presence of organic acids and co2 resulting from the decay of organic detritus. 3. the chemical composition of the water is controlled by sio2 dissolution kinetics in the case of proper cave and/or streambed morphology 4. the strongest dissolution/reprecipitation agent is the condensed atmospheric moisture with extremely low ec and high sio2–si concentration. 5. the siliceous speleothems are mostly represented by cyanobacterian stromatolites. columnal stromatolitic forms are likely to have been formed by fi lamentous cyanobacteria from the order oscillatoriales; the chalk-like peloidal layers were formed by nostoc-type cyanobacteria. inorganically precipitated siliceous speleothems occur, too. some of them used spider webs as supporting structures. acknowledgement the slovak authors are grateful to the ministry of education of the slovak republic for fi nancial assistance, then to the apvv agency for grant no. 0251-07 and the vega agency for grant no. 1/0246/08. our thanks also belong to the reviewers robert a.l. wray (university of wollongong, australia) and juan r. vidal romaní (universidad de coruña, spain) for their useful comments and discussions. we are also grateful to ing. erik kapucian, ing. zoltán ágh and mr. igor-maría elorza for fi eld assistance. references aubrecht, r., brewer-carías, ch., šmída, b., audy, m. & kováčik, ľ. (2008): anatomy of biologically mediated opal speleothems in the world’s largest sandstone cave cueva charles brewer, chimantá plateau, venezuela. – sediment. geol., 203, 3–4, 181– 195. bauters, t.w.j., di carlo, d.a., steenhuis, t.s. & parlange, j.-y. (2000): soil water content dependent wetting front characteristics in sand. – j. hydrol., 231–232, 244–254. bourrelly, p. & depuy, p. (1973): quelques stations françaises de geitleria calcarea, cyanophycée cavernicole. – schweiz. z. hydrol., 35, 136–140. brehm, u., gorbushina, a. & mottershead, d. (2005): the role of microorganisms and biofi lms in the breakdown and dissolution of quartz and glass. – palaeogeogr., palaeoclim., palaeoecol., 219, 117–129. brewer c.ch. (1972): cerro autana, elite descubre otra maravilla del mundo [cerro autana, elite discovers another wonder of the world – in spanish]. – rev. elite, 2.457, 36–43. brewer, c.ch. (1973): mesetas de jaua, guanacoco y sarisarińama [plateaus of jaua, guanacoco and sarisarińama – in spanish]. – bol. soc. venez. ci. nat., 30, 127, p. 32. brewer, c.ch. (1974): en busca de los orígenes [searching for origins – in spanish]. – rev. el farol, la calidad de la vida, 1, 18–23. brewer, c.ch. (1976): cuevas del cerro autana [caves of the cerro autana – in spanish]. – natura, 22, 549–624. briceńo, h.o. & schubert, c. (1990): geomorphology of the gran sabana, guayana shield, southeastern venezuela. – geomorphology, 3, 125–141. briceńo, h.o. & schubert, c. (1992): geología. – in: huber, o. (ed.): chimantá. escudo de guayana, venezuela. un ensayo ecológico tepuyano. caracas, 53–60. chalcraft, d. & pye, k. (1984): humid and tropical weathering of quartzite in southeastern venezuela. – z. geomorphol., 28, 321– 332. colvée, p. (1973): cueva en cuarcitas en el cerro autana [cave in quartzites in cerro autana – in spanish]. – bol. sve, 4, 5–13. forti, p. (1994): los depositos quimicos de la sima aonda superior y de otras cavidades del auyán–tepui [chemical deposits of the sima aonda superior and other cavities of the auyan tepui – in spanish]. – bol. sve, 28, 1–4. friedmann, i. (1955): geitleria calcarea n.gen. et n.sp., a new atmophytic lime-encrusting blue-green alga. – bot. not., 108, 439– 445. geologia croaticaroman aubrecht et al.: venezuelan sandstone caves: a new view on their genesis, hydrogeology and speleothems 361 golubic, s. (1976): organisms that build stromatolites. – in: walter, m.r. (ed.): stromatolites. elsevier, developments in sedimentology, 20, 113–126. gorbushina, a.a., boettcher, m., brumsack, h.-j., krumbein, w.e. & vendrell-saz, m. (2001): biogenic forsterite and opal as a product of biodeterioration and lichen stromatolite formation in table mountain systems (tepuis) of venezuela. – geomicrob. j., 18, 117–132. gradziński, m. & jach, r. (2001): jaskinie lawowe – zarys problematyki [lava caves – outline of the problem – in polish]. – przegl. geol., 49, 12, 1191–1196. hill, c.a. & forti, p. (1986): cave minerals of the world. – publ. nat. speleol. soc., 238 p. jones, b., renaut, r.w. & rosen, m.r. (2001): microbial construction of siliceous stalactites at geysers and hot springs: examples from the whakarewarewa geothermal area, north island, new zealand. – palaios, 16, 73–94. kashima, n., teruo, i. & kinoshita, n. (1987): diatom, contributors of coralloid speleothems, from togawa-sakaidani-do cave in miyasaaki prefecture, central kyushu. – japan int. j. spel., 16, 95–100. kashima, n. & ogawa, t. (1995): a note on biogenic effect of coralloid speleothems in round mountain lava cave, oregon, u.s.a. – j. spel. soc. japan, 19, 8–12. konhauser, k.o., phoenix, v.r., bottrell, s.h., adams, d.g. & head, i.m. (2001): microbial–silica interactions in icelandic hot spring sinter: possible analogues for some precambrian siliceous stromatolites. – sedimentology, 48, 2, 415–433. konhauser, k.o., jones, b., reysenbach, a.-l. & renaut, r.w. (2003): hot spring sinters: keys to understanding earth’s earliest life forms. – can. j. earth sci., 40, 1713–1724. kunicka-goldfinger, w. (1982): preliminary observations on the microbiology of karst caves of the sarisarińama plateau in venezuela. – bol. sve, 19, 133–136. kylin, h. (1937): über die farbstoffe und die farbe der cyanophyceen [about colouring agent and colour of cyanophytes – in german]. – k. fysiogr. sällsk. lund, förh., 7, 131–158. léveillé, r.j., fyfe, w.s. & longstaffe, f.j. (2000): geomicrobiology of carbonate–silicate microbialites from hawaiian basaltic sea caves. – chem. geol., 169, 339–355. liu, y., steenhuis, t.s. & parlange, j.-y. (1994): formation and persistence of fi ngered fl ow fi elds in coarse grained soils under different characteristics in sands. – j. hydrol., 159, 187–195. marker, m.e. (1976): note on some south african pseudokarst. – bol. sve, 7, 5–12. martini, j.e.j. (1979): karst in black reef quartzite near kaapsehoop, eastern transvaal. – ann. south afr. geol. surv., 13, 115–128. martini, j.e.j. (2000): dissolution of quartz and silicate minerals. – in: klimchouk, a. b., ford, d. c., palmer, a. n. & drey brodt, w. (eds.): speleogenesis, evolution of karst aquifer. publ. nss, huntsville, alabama, 171–174. mecchia, m. & piccini, l. (1999): hydrogeology and sio2 geochemistry of the aonda cave system (auyán-tepui, bolivar, venezuela). – bol. sve, 33, 1–18. piccini, l. (1995): karst in siliceous rocks karst landforms and caves in the auyán-tepui massif (est. bolivar, venezuela). – int. j. speleol., 24, 1–4, 41–54. quesada, a. & vincent, w.f (1997): strategies of adaptation by antarctic cyanobacteria to ultraviolet radiation. – eur. j. phycol., 32, 335–342. rasteiro, m.a. (2000): estabelecido novo recorde sul-americano de profundidade em cavernas [new south american record established in caves depth – in portuguese]. – sbe notícias, 2, 39, 1. reis, n.j. & yánez, g. (2001): o supergrupo roraima ao longo da faixa fronteirica entre brasil–venezuela (santa elena del uairen— roraima mountain) [the roraima supergroup within the stripe along the brazil–venezuelan borderline (santa elena del uairen— roraima mountain) – in portuguese]. – in: reis,n.j. & monteiro, m.a.s. (eds.): contribuicao a geologia da amazonia, volume 2: manaus, brazil. sociedade brasileira de geologia, 113–145. santos, j.o.s., potter, p.e., reis, n.j., hartmann, l.a., fletcher, i.r. & mc naughton, n.j. (2003): age, source, and regional stratigraphy of the roraima supergroup and roraimalike outliers in northern south america based on u–pb geochronology. – gsa bull., 115, 3, 331–348. szczerban, e. & gamba, j. (1973): cuevas y simas en areniscas precámbrias de la formación roraima, territorio federal amazonas y estado bolívar [caves and abysses in the precambrian arenites of the roraima formation, amazonas federal territory and bolívar state – in spanish]. – bol. sve, 4, 2, 226. szczerban, e. & urbani, f. (1974): carsos de venezuela. parte 4: formas cársicas en areniscas précambricas del territorio federal amazonas y estado bolívar [karsts of venezuela. part 4: karstic forms in the precambrian arenites of the roraima formation, amazonas federal territory and bolívar state – in spanish]. – bol. sve, 5, 1, 27–54. szczerban, e., urbani, f. & colveé, p. (1977): cuevas y simas en cuarcitas y metalimolitas del grupo roraima, meseta de guaiquinima, estado bolivar [caves and abysses in quartzites and metasiltstones of the roraima group, meseta de guaiquinima, bolivar state – in spanish]. – bol. sve, 8, 127–154. šmída, b., audy, m. & vlček, l. (2003): expedícia roraima 2003. jaskyňa kraštálové oči [roraima 2003 expedition. crystal eyes cave – in slovak]. – bull. sss, 34, 2 (spec. vol.), 190 p. šmída, b., brewer-carías, ch. & audy, m. (2005a): cueva charles brewer – najväčšia kvarcitová jaskyňa sveta [cueva charles brewer – the largest quartzite cave in the world – in slovak and spanish]. – bull. sss, 36, 3, 1–178. šmída, b., audy, m. & mayoral, f. (2005b): cueva charles brewer: largest quartzite cave in the world. – nss news, january 2005, 13–31. urbani, f. (1986): notas sobre el orígen de las cavidades en rocas cuarcíferas precámbrias del grupo roraima [notes about the origin of the caves in the precambrian quartzose rocks of the roraima group – in spanish]. – interciencia, 11, 298–300. urbani, f., comp’re, ph. & willems, l. (2005): opal-a speleothems of wei-assipu-tepui, roraima province, brazil. – bol. sve, 39, 21–26. vidal romaní, j.r. & twidale, ch.r. (1998): formas i paisajes graníticos [granitic forms and landscapes – in spanish]. – universidade da coruńa, 411 p. vidal romaní, j.r. & vaqueiro rodrigues, m. (2007): types of granite cavities and associated speleothems: genesis and evolution. – nature conserv., 63, 41–46. vincent, w.f. & roy, s. (1993): solar ultraviolet-b radiation and aquatic primary production: damage, protection, and recovery. – envir. rev., 1, 1–12. voicu, g., bardoux, m. & stevenson, r. (2000): litostratigraphy, geochronology and gold metallogeny in the northern guiana shield, south america: a review. – ore geol. rev., 18, 211–236. geologia croatica geologia croatica 61/2–3 362 white, w.d., jefferson, g.l. & haman, j.f. (1966): quartzite karst in southeastern venezuela. – int. j. speleol., 2, 309–314. whitton, b.a. (1987): the biology of rivulariaceae. – in: fay, p. & van baalen, c. (eds.): the cyanobacteria – a comparative review. elsevier, 513–534. willems, l., comp’re, ph., hatert, f., puclet, a., vicat, j. p., ek, c. & boulvain, f. (2002): karst in granitic rocks, south cameron: cave genesis and silica and taranakite speleothems. – terra nova, 14, 355–362. wray, r.a.l. (1997a): a global review of solutional weathering forms on quartz sandstones. – earth. sci. rev., 42, 137–160. wray, r.a.l. (1997b): quartzite dissolution: karst or pseudokarst?. – cave and karst sci., transact. brit. cave res. assoc., 24/2, 81– 86. wray, r.a.l. (1999): opal and chalcedony speleothems on quartz sandstones in the sydney region, southeastern australia. – australian j. earth sci., 46, 4, 623–632. manuscript received february 27, 2008 revised manuscript accepted may 19, 2008 peh & miko.indd 1. introduction much research has been undertaken to elucidate the problem of the relationship between drainage basin lithology and geochemistry of the drainage system deposits, whether the latter be confined strictly to the stream channel, or spread over the extended area beyond its banks. in both cases attention was largely concentrated on evaluating the geochemical background and detecting the elevated values which reflect possible mineralization in a survey area (e.g. rose et al., 1970; bonham-carter et al., 1987), as well as on modelling the geochemical variability and dilution effects impact of geomorphological variables in weighing the lithological influence on geochemical composition of stream and overbank sediments: a regression model for the žumberak area (nw croatia) zoran peh and slobodan miko (e.g. jenson & trautwein, 1984; hawkes, 1976; bonham-carter & goodfellow, 1984; bonham-carter et al., 1987; carranza & hale, 1997). regression analysis has been utilized as a particularly useful mathematical method in relating the desired chemical element to the mapped lithological units. this aptitude is most assuredly rooted in the broad agreement that compositional (geochemical, mineral) and other properties of drainage basin fills are inseparably connected with drainage basin evolution through the delicate process–response relationship and feedback mechanisms in alluvial systems (e.g. johnsson, 1993; weltje et al., 1998). in all the above cases however, regression models invariably made use of the areal proportions of a particular lithology within a catchment area putting these in the role of independent variables. this concept simply disregards the fact that not all parts of the drainage basin supply its valley and channel floors with products of weathering and erosion uniformly in space and time. in scaling the eroding and resisting forces in drainage basin systems many parameters interact, causing the sediment yield to depend not only on the physiographic properties of the rocks but also on the character of the forces of denudation. these, in turn, operate on different temporal and spatial scales with regard to slopes and channel–reach areas. denudation, as a total sum of erosion processes, assumes that sediment is derived in equal portions from all subareas of the watershed, but it tells little about the redistribution of weathered and eroded material within a drainage basin (ritter, 1978). it is also well known that only the erosive power of water flowing in clearly defined channels represents a truly effective transportation and erodive agent, while, on the other hand, unconcentrated overland flow on slopes acts more slowly and less efficiently, particularly in the presence of rich vegetation cover (kirkby, 1969). thus, the two basin subsystems seem to operate independently and out-ofphase, which is the reason why the understanding of their process–form relationship becomes fraught with difficulties. their co-dependence during historical times (<200 yrs; ritter, 1988) can be observed almost solely in a narrow belt of slope adjacent to the stream channel, particularly in its upstream reaches. this is where incising streams erode both vertically and laterally, affecting not only the channel floor but also the lower geologia croatica 56/2 199–214 6 figs. 5 tabs. zagreb 2003 key words: drainage basin, channel–reach morphology, sediment supply, lithology, geochemical composition, stream sediment, overbank sediment, multiple regression analysis, žumberak, croatia. institute of geology, sachsova 2, hr-10000 zagreb, croatia; e-mail: zpeh@igi.hr abstract the two multiple regression models were compared on the assumption that the geochemical composition of the alluvial material is basically originally derived from the bedrock lithology of a drainage basin of the žumberak area (nw croatia). the latter was integrated with both stream sediment and overbank sediment geochemical data via the two essentially different approaches as regards the catchment basin geomorphological data: (1) as the relative area of influence representing a portion of the catchment basin occupied by a certain rock type; (2) as the relative “line” of influence representing a narrow tract of a certain rock type traversed by the majority of perennial streams which form the active stream network. the model comparison was accomplished on the basis of the goodness-of-fit test for both experimental designs and for the same set of data. the most important result of these experiments highlights the linear approach as the more appropriate model for ascertaining the lithological influence on the analyzed sample media. this can be explained by the stronger erosive and transportational power of the water which flows in the well defined channel network in contrast to the unconcentrated surface runoff in the interfluvial area, coupled with the buffering effects of rich slope and riparian vegetation, which is characteristic of the žumberak heartland. 200 geologia croatica 56/2 201peh & miko: impact of geomorphological variables in weighing the lithological influence... portions of the valley sides. often they undercut channel slopes, particularly during flood events, inducing rapid mass-movements as a result (usually bedrock and regolith landslides). in contrast, slopes that lie higher up the hillside, in the vicinity of the watershed, rarely experience such energetic geomorphologic events which, together with the mitigating effects of dense slope and riparian vegetation, may effectively reduce the amount of regolith reaching the channel (owens et al., 1999). therefore eroded material, which is transported in various forms of stream-channel load and deposited downstream as stream or overbank (floodplain) sediment, seldom evenly reflects the lithological characteristics of both drainage basin subsystems either in geochemical or mineral composition. moreover, wider valleys with alluvium infill in the downstream reaches of a channel usually serve as a buffer zone, considerably decreasing their susceptibility to disturbance from slope processes (montgomery & buffington, 1997). the question arises how to best fit geomorphological variables into the scheme of assessing the real lithological imprint on the geochemical composition of stream and overbank sediments, especially when considering that interfluvial areas occupy a vastly greater proportion of the catchment area. the areal approach that utilizes the relative proportions of distinctive lithology within a drainage basin takes into account inappropriately large portions of the whole catchment characterized by very slow denudation processes. these, in turn, provide the valley floors with relatively small quantities of waste material over a short time interval (geomorphological steady time). in this case, accumulation of the sediment load in channels appears to be quite out of phase with erosion and transportation processes on far reaches of the upper slopes in the vicinity of the watershed where almost no erosion occurs. we are prone to use the linear approach instead, which takes into account only the section of distinctive lithology along the active stream reaches, expecting a closer relationship between the deposits with pertinent channel-floor or bank lithology. thus, the aim and scope of this study is to compare the two approaches by the use of the multiple regression model for quantifying the impact of various types of rocks on the selected set of elements. this was accomplished on the basis of the goodness-of-fit test for two different experimental designs and for the same set of data including geochemical content of stream and overbank sediment samples. 2. geological framework of the study area the study area encompasses a large proportion of the žumberak region, situated in western croatia (on the slovenian border), near the capital, zagreb. broadly, it is a mountainous system occupying the interfluvial belt between the sava, kupa and krka rivers, with the žumberak mt. to the west, and samobor mt. to the east as its main constituent bodies (fig. 1). the landscape combines many characteristics from the two distinct topographic and geologic provinces: dinaric carbonate terrains with a relatively poor and undeveloped drainage network, in which a variety of karstic phenomena abound, and pannonian, mostly non-carbonate, highly dissected terrains. geologically, it represents a complex terrain with different tectonic and lithological settings (fig. 2). interaction and feedback between tectonics and surface processes produced a heterogeneous massif with a number of major tectonic blocks which have suffered horizontal or vertical movements of various intensity. the greatest proportion of the study area is composed of the autochtonous žumberak tectonic unit which consists of various rocks deposited from the middle permian to palaeogene (šikić et al., 1977). its western part is an upthrown area which is lithologically relatively monotonous due to the predominance of carbonate rocks – triassic dolomites and jurassic limestones – over pelagic siliciclastic rocks of upper cretaceous age (pleničar et al., 1975; premru et al., 1977; bukovac et al., 1983; herak & bukovac, 1988). in contrast the samobor mt. is much more tectonically dissected and lithologically variable, with permian rocks, predominantly sandstones, in the core of the autochthonous block. its border with the allochthonous žumberak–medvednica knappe unit is often fragmented by vertical neotectonic faults. the latter consists of the sedimentary rocks of triassic, jurassic and cretaceous age which were thrust over the older substructure during the alpine orogenesis, but the present appearance of the horizontally dislocated mass resulted mostly from the subsequent partitioning of individual minor blocks which reduced its original proportions. in effect, both of these units suffered intense fragmentation during the neotectonic phase, particularly since the end of the upper pliocene, which, together with surface processes, were an important factor in shaping the modern uplifted territory. in contrast, the southern borders of the study area went through the different tectonic and morphological changes which resulted in a steady tectonic subsidence and final formation of the karlovac depression (velić, 1983). lithology the composite (dinaric–pannonian) character of the žumberak territory is well reflected in the intricate lithological patterns. there is a variety of carbonate and siliciclastic facies combined in a fractured mosaic of blocks of different ages which, for the purpose of this work, is limited to a very simplified and sparse sketchmap (fig. 2). throughout the area the mesozoic carbonate rocks predominate, with the emphasis on the middle and upper triassic dolomite series. these rocks are mostly massive, with almost no fossil content, which prevents further chronostratigraphic determination (šikić et al., 200 geologia croatica 56/2 201peh & miko: impact of geomorphological variables in weighing the lithological influence... 1977). the bulk of the dolomite material, particularly of upper triassic age, originated from dolomitization of the calcareous sediments, most probably in the early phase of diagenesis. later, due to the long lateral transport, the allochthonous mass has become thickly jointed, prone to crushing and easily erodable. dolomites (upper triassic in particular) provide the major supply for both the active stream sediment and alluvial fill in many intermontane valleys. the other member of carbonate lithology is represented by the various types of limestones. in contradistinction to the triassic monotonous dolomite sequence where stromatolite-type facies is dominant, limestones are distinguished by ample facies diversity throughout the whole stratigraphic column ranging from the middle permian to the miocene. their vertical and horizontal distribution, though, is thin and locally very confined. often they are interbedded within the more frequent siliciclastic sedimentary rocks. only jurassic limestones can be postulated as representing almost entirely uninterrupted sedimentation, and specifically under pelagic conditions, during the entire period. their sequence is represented by pelagic (bio)micrites (mostly liassic–doger) and (bio)detrital limestones with interbedded cherts (mostly malmian). cherts originated from the silicification of calcareous rocks which can be seen in progressive transition from the micritic limestones. the siliciclastic rocks occupy a considerably lesser portion of the study area. most generally, they consist of two different sequences of stratified rocks which are temporally widely separated. the older group of sedimentary rocks is bound to an earlier, permo–triassic sedimentation cycle. another sequence comprises younger, mostly neogene, siliciclastic material which is often unconsolidated or loosely consolidated and thus easily erodable. the oldest rocks are of middle and upper permian age, developed in a molasse-type facies. these are very diverse, but represent mostly sandstones and, more rarely, (quartz)conglomerates. shales and siltites occur only as intercalations between the former. associated with them are rare occurrences of copper and iron ore, and also, towards the triassic boundary, fig. 1 generalized geological map showing location of the study area (after šikić et al., 1977; pleničar et al., 1975, and bukovac et al., 1983): q2 – holocene in general; q1 – pleistocene in general; plq – plio–quaternary (unconsolidated sediments); ng – neogene in general (clastic rocks); k2 – upper cretaceous (limestone, dolomites and flysch-like series); j – jurassic in general (predominantly limestones); t3 – upper triassic (predominantly dolomites); t1 – lower triassic (predominantly clastic rocks); pz – middle and upper permian (predominantly clastic rocks). 202 geologia croatica 56/2 203peh & miko: impact of geomorphological variables in weighing the lithological influence... gypsum and anhydrite beds as a result of shallowing of the sedimentary basin (šinkovec, 1971; šiftar, 1989). the lower triassic also developed a typical shallow-water sandstone facies. in the lower part of the series the terrigenous clastics are dominant, but the carbonate component increases toward the younger strata. this permo–triassic complex is exposed in the eastern part of the study area (samobor mt.) with patches of lower triassic on its extreme southwest fringes. a characteristic clastic series is associated with the upper cretaceous transgression and subsequent deepening of the sedimentary environment. it consists of various flysch-type rocks, spreading over most part of the žumberak. genetically, these contain pelagites, hemipelagites, turbidites and contourites (babić, 1974; mrinjek, 1992) with the most frequent lithologic members such as calcareous and clayey marls, shales, calcarenites and breccias (basal), occasionally interbedded with cherts and platy limestones. the peripheral area of žumberak is composed of diverse clastic facies deposited during the tertiary period, mainly in the neogene. these rocks overlie the southern part of the terrain in an almost uninterrupted stratigraphic sequence ranging from the miocene to pliocene–quaternary. to the east and north (slovenia) they appear only as limited erosion caps transgressively overlying the older mesozoic, mostly carbonate rocks. in the central parts of žumberak they are virtually nonexistent. depending on the unstable sedimentary conditions during the observed time span, the lithology varied from a typical transgressive series beginning with conglomerates, to deep-water clastic deposits marked by calcareous and clayey marls. due to progressive shallowing of the sedimentary environments towards the end of neogene the bulk of sedimented material fig. 2 lithological sketch-map of the study area (compiled from the geological maps of šikić et al., 1977; pleničar et al., 1975 and bukovac et al., 1983): 1 – plq (plio–quaternary and quaternary unindurated siliciclastic sediments; 2 – tckl (tertiary clastic sedimentary rocks); 3 – fl (cretaceous flysch-like series); 4 – pmkl (upper palaeozoic–triassic clastic sedimentary rocks); 5 – lim (limestones, predominantly jurassic); 6 – dol (dolomites, predominantly middle and upper triassic); 7 – faults. 202 geologia croatica 56/2 203peh & miko: impact of geomorphological variables in weighing the lithological influence... is of a sandy and marly type. marls, marly clays, sands, sandy marls and clays predominate through the entire pliocene and extend into the quaternary (plio–pleistocene). this material is weakly consolidated or, most often, unconsolidated and thus easily erodable, which is why peripheral valleys in the southern parts of žumberak are filled almost solely with its weathering products. 3. drainage network dendritic and centrifugal patterns, with minor modifications, characterize the drainage network of the žumberak mountainous landscape. the pattern is primarily tectonic, particularly owing to the vigorous uplift and vertical faulting during the pliocene– pleistocene periods (prelogović, 1969; dujmović & bognar, 1995). the majority of streams with any alluvium fill, which traverse this block-faulted structural morphology are of the fifth-, less frequently of the sixth-order. draining mostly the peripheral mountain faces they are directed to the main regional base-levels – the valleys of the sava, kupa and krka rivers. only two of the sixth-order streams transverse its central part to which a great many fifthor lowerorder streams gravitate (the centripetal, mountain drainage network). of them, the bregana is a tributary of the sava river to the east, while kupčina empties into the kupa river to the south. both of these, their tributaries, and the majority of the fifth-order streams in general, contain depositional flood plains. in contrast, due to their higher-gradient channels, the fourth-order valleys only rarely experience aggradational processes, sometimes even cutting their channels into bedrock. the channel–reach processes the majority of sampled streams in the study area have developed a certain type of alluvial-channel morphology. bedrock channel substrate is only found in exceptional cases at least as drainage basins of fourthor higher order are concerned. this is of great importance as regards the interaction of channel and slope processes which control the delicate relationship between erosion, transport and deposition of the weathered material. in streams cut in bedrock (mostly third-order, or lower), with steep channel gradients, there is a strong coupling between processes in channels and on their adjacent slopes. since interfluvial distances are often considerably reduced by a progressively branching valley network (often with colluvial substrates where streams are present) in the upper reaches of a drainage basin, vertical incision and upslope debris flow operate more in unison. the mixing of waste material from both environments may be so effective as to smooth the impact of linear and areal aspects of lithology on the compositional variables of channel sediment. this does not occur in the downstream reaches of the channel with progressively lower gradients where, due to the valley widening, the sediment supply from the valley sides is virtually cut off, leaving the bedload composition to depend almost solely on the processes along the stream channel. depending on the channel gradient and discharge, these may vary from scour (mostly lateral) to deposition of the eroded material from upstream distances which would leave the linear basin aspects as the only geomorphological variable relevant for determining the influence of bedrock lithology on geochemistry or mineralogy of the load. in the investigated area these channel reaches are essentially of three morphological types (according to montgomery & buffington, 1997): the žumberak heartland abounds with drainage basins of the plane-bed, more rarely step–pool and intermediate channel–reach morphologies, while on its borders, particularly within the kupa catchment area, mostly pool–riffle morphology occurs (figs. 3a–d). all of these are distinguished by relatively low gradients varying from <0.015 to 0.03 m/m (measured from the sampling sites upstream) which represents typical values for the majority of mountain drainage basins (tuckfield, 1980; montgomery & buffington, 1997), but the intricate relationship between the bank erosion and character of bedload must be treated with caution (paola, 2000). thus, no bank (lateral) erosion will be found representative of mountain valleys because of the prevalence of coarse material transported along the channel. the peripheral, mostly sandy-bedded streams will experience occasional bank failures, especially under high discharge events, as may be the case in alluvial segments with silt–sand overbanks on the southern slopes of samobor mt. (peh & miko, 2001). dry valleys another, even greater, problem in evaluating the geomorphological variables may be the presence of dry valleys in the upper reaches of valley segments, which are irrespective of modern channel type and processes. the majority of thirdor lower order valleys which occupy the upper areas of the larger drainage basins in the žumberak region are streamless (fig. 3e). these valleys must have been cut by streams some time in the past when climatic conditions were different. climatic changes in the post-glacial period, which commenced at the termination of the pleistocene ice age, were characterised with increasing amounts of atmospheric moisture. streams swollen by meltwater and higher rainfalls must have had an immediate impact on raising the level of the water table and, coupled with other factors (such as, local and regional uplift), might have ultimately resulted in prompt expansion of the drainage network (e.g. gregory & walling, 1973; ollier, 1981). later, with a fall in the average precipitation owing to retrograde climatic changes up to the present time, the latter was contracted to its present extent. thus, dry valleys portray a major or minor 204 geologia croatica 56/2 205peh & miko: impact of geomorphological variables in weighing the lithological influence... discrepancy between the more restricted size of the present stream pattern with regard to the valley pattern which it partly occupies (gregory & walling, 1973). this discrepancy has a major impact on the effective cutoff of the higher parts of the mountain drainage basins from the rest which contain the active stream network, as regards modern geomorphological processes. it was shown by the morphometric factor model of the bordering region (hrvatsko zagorje) that coupling between the slope and channel processes is effective only when the active stream network (stream density) is considered, while the total valley network (drainage density) relates to an altogether different subsystem of drainage basin processes (peh, 1994, 1997). in such a case one would relate erosion, transport and deposition only to the valleys with perennial streams while intermittent streams, and dry valleys in particular, contribute little to the recent basin change. consequently the compositional scheme of the waste, transported and deposited load, sampled at the basin outlets, would be in concordance with more recent conditions along the stream channels and their active tributaries than with those in interfluvial areas occupied by relic fluvial landforms. 4. sampling field investigations encompassed an area of about 600 km2 with 46 fourthand fifth-order mountain drainage basins ranging in size from 0.65 to 26.00 km2 (table 1, fig. 4). in the majority of basins both stream and overbank material were obtainable for sampling which was carried out in a “pair” design on each site wherever possible. therefore both media were regularly collected from the same spot within a few metres fig. 3 most frequent types of alluvial channel–reach morphology in the žumberak area: (a) intermediate bedrock – alluvium channel–reach morphology with distinctive features of cascade and planebed alluvial channel types (sridnjak; sampling point 350); dolomites. (b) typical plane-bed alluvial channel morphology characteristic for the intermontane drainage basins in the west central parts of žumberak (slapnica; sampling point 338); dolomites. c) typical step–pool alluvial channel characteristic for most of the mountain drainage basins in the east central part of žumberak (bregana, immediately downstream from the confluence with rakovac; sampling point 276); dolomites. d) pool–riffle channel morphology on the southwest periphery of žumberak (stupanj; sampling point 341); sands and marls. e) dry valley in the higher altitudes of the east central žumberak, near stojdraga. a b c d e 204 geologia croatica 56/2 205peh & miko: impact of geomorphological variables in weighing the lithological influence... distance except in those cases where valley or channel fills were absent. for the six fourth-order drainage basins the overbank sample was unavailable. in one drainage basin of fifth order the stream sediment was not collected. the former case was due to the absence of alluvium in high-gradient valleys, while in the latter the sediment load was present but not sampled because of the obvious household contamination in the vicinity of the sampling site. sometimes the fine-grained, silt–clay content of the bed similar to that of the adjacent banks arose suspicion as to its origin and the possibility for mistaking the sample media, but earlier investigations have shown that this is rarely the case (peh & miko, 2001). case sample drainage basin str ov order catchment slope area (m/100 m) (km2) 1 4 kamenjak + – 4 sava 16.67 2.28 2 7 potok 7 (pod vrh) + – 4 sava 3.33 1.09 3 41 ludvić + + 4 sava 4.21 4.41 4 194 orejovec + + 4 kupa 0.88 5.25 5 196 piroški potok (sl) + + 4 krka 2.67 6.03 6 197 skradnja (sl) + + 4 krka 2.35 5.07 7 214 fučanski jarak + + 4 sava 6.67 2.81 8 220 jarak + – 4 sava 4.00 3.64 9 221 velika draga + + 4 sava 6.67 2.99 10 349 jaševnica + + 4 kupa 1.33 12.02 11 350 sridnjak + – 4 kupa 10.67 1.38 12 351 ponornica 351 + + 4 krka? 1.82 1.01 13 354 ponornica 354 + + 4 kupa? 0.62 2.86 14 365 dobri potok + – 4 sava 6.67 3.36 15 366 vorbaščica + + 4 kupa 2.86 4.56 16 367 potok 367 + – 4 kupa 3.81 2.23 17 371 potok 371 + + 4 kupa 2.85 0.65 18 19 škrobotnik + + 5 sava 2.20 8.79 19 21 breganica + + 5 sava 1.60 11.21 20 42 lipovačka g. + + 5 sava 0.72 26.00 21 43 rudarska g. + + 5 sava 0.72 15.48 22 178 reka + + 5 kupa 1.60 9.19 23 187 okićnica + + 5 kupa 0.50 19.11 24 190 potok 190 + + 5 kupa 0.75 3.15 25 191 stošinec – + 5 kupa 0.77 3.54 26 198 sušica (slo) + + 5 krka 1.40 9.79 27 275 bregana + + 5 sava 2.32 14.52 28 276 rakovac + + 5 sava 2.11 8.39 29 328 žumberačka reka + + 5 kupa 1.33 15.96 30 331 sušica + + 5 krka 2.86 8.51 31 333 suvaja + + 5 kupa 0.98 22.91 32 334 potok + + 5 kupa 2.22 5.44 33 335 svilnica + + 5 kupa 3.08 3.63 34 337 ponikva + + 5 kupa 0.19 6.46 35 338 slapnica + + 5 kupa 0.57 16.25 36 339 puškarov jarak + + 5 kupa 1.74 9.77 37 340 brebrovac + + 5 kupa 0.97 5.69 38 341 stupanj + + 5 kupa 0.77 4.48 39 342 stiska + + 5 kupa 0.91 11.43 40 343 malunja + + 5 kupa 0.98 6.87 41 344 gonjeva + + 5 kupa 1.13 8.11 42 345 kamenica + + 5 kupa 1.00 17.23 43 346 bukovica + + 5 kupa 0.77 12.25 44 347 slatinek + + 5 kupa 0.63 4.33 45 368 stiper + + 5 kupa 0.8 5.72 46 370 selna + + 5 kupa 0.37 5.32 table 1 general data describing the sample sites. legend: str – stream sediments; ov – overbank sediments. 206 geologia croatica 56/2 207peh & miko: impact of geomorphological variables in weighing the lithological influence... the sample sites were selected at the basin outlets, sufficiently upstream from the confluence with higher (or the same order) streams in order to avoid sampling the sediment that may result from mixing of material from the two channels during the flood flow. active stream sediment, which represents the composite of the recently deposited bed load material, was collected from several spots (ordinarily 5–10 as recommended by salminen et al., 1998) over a short channel stretch upstream of the selected site. simultaneously, a single overbank sediment sample was taken from approximately the same point at the exposed area of either bank of a channel. the latter is composite material collected from the bank section ranging in height from 25 cm beneath the surface down to the water level (usually 0.5 to 2 m thick), while the first 25 cm of the upper, near surface horizon was avoided because of possible anthropogenic disturbance and pedogenesis. in both cases a quantity of about 3 kg of sediment was collected to yield enough representative material for sieving and analysis. sample preparation collected samples were air-dried (at <40ºc) for approximately three months. after drying, the samples were disaggregated in a porcelain mortar, homogenized, and finally dry-sieved through stainless-steel screens to the <125 μm size fraction. this fraction was preferred because the highest concentration of most of the elements, especially trace elements, occur in the fine-grained, usually 63–125 μm size fraction (e.g. rhoads & cahill, 1999). also, some studies show that the <125 μm size fraction can contribute to more than 95% of the particles in most samples (swennen et al., 1998). analytical methods analytical work was performed at the acme analytical laboratories in vancouver, canada, where samples were subjected to multi-acid digestion icp analysis and geochemical hg analysis by flameless aa. a total of 36 elements were thus analyzed with au, be, bi, mo, u and w having concentrations invariably, and ag, sb, sn and cd mostly under the detection limit. 5. regression analysis regression analysis is one of the most often utilized techniques in multivariate as well as bivariate analysis for assessing the relationship between variables in a data set. in multivariate solutions a multiple linear regression is used to define the simultaneous relationship between one dependent (or response) variable fig. 4 sample map showing distribution of fourthand fifth order drainage basins in the study area. 206 geologia croatica 56/2 207peh & miko: impact of geomorphological variables in weighing the lithological influence... y against a number (n) of independent (or predictor) variables x1–n. this is done by finding the “best-fit” straight line via the method of least squares estimation in which deviations of the dependent variable from that line are minimized. the problem on which the analyis is most frequently centred, as in this case, is to assess the contribution of predictor variables to the overall regression model. in other words, it is useful to find that portion of the total variance in a response variable which can be explained by a set of influencing variables. this value is usually termed the “goodnessof-fit”, or a multiple coefficient of determination (r2), which is, in fact, the multiple correlation coefficient of a particular variable squared. in the actual case, the content of each analysed element represents a particular dependent variable in a regression model, while the lithological influences, expressed either in the form of areal or linear proportions of a specific rock unit within a drainage basin, are represented by a set of independent variables. variables an assemblage of 26 elements consisting of eight major and 18 minor and trace elements were selected as independent variables in the regression analysis. in order to obtain the best possible fit of the model a number of these variables should have been submitted to the transformation procedure. positively skewed frequency distributions were observed among most of the minor and trace elements in both stream sediment and overbank sediment data sets. thus, the conventional log-transformation was carried out for most of the minor and trace elements such as cu, pb, zn, ni, co, mn, as, th, sr, ba and hg, but also for some major elements such as ti, mg and p. six rock types that dominate the terrain lithology were specified as independent variables in the regression analysis (fig. 2). these are: (1) clastic sedimentary rocks of the tertiary period (mostly neogene) – tckl; (2) clastic sedimentary rocks of upper palaeozoic– triassic – pmkl; (3) cretaceous flysch-like series – fl; (4) limestones (dominantly jurassic) – lim; (5) dolomites (middle and upper triassic types are prevalent) – dol; (6) plio–quaternary and quaternary sediments – plq. the above scheme may seem grossly oversimplified, but it serves its purpose to the extent to which the great variety of clastic and carbonate facies is expected to contribute to the overall geochemical composition of the sample media. the simultaneous use of variables belonging to the same realm of sedimentary rock types, namely dolomites and limestones, is necessary when considering their strongly contrasted weathering patterns. crushed and mylonitized dolomite rocks represent a classical “clastic factory” (hovius & leeder, 1998) supplying the valley floors with abundant sediment flux, while limestones are much more resistant to physical weathering. these six variables are given the form of the relative proportions of each rock unit within a drainage basin, yet, because calculated on different grounds, they formulate the two experimental designs employed here. the first approach is well-known and operates on the basis of areal proportions of the specified drainage basin lithology, while the second is more specific and takes into account its linear proportions along the perennial streams. in the latter case all blue streamlines have been scanned from the topographic maps (scale 1:25,000). defined as above, the lithological variables can be regarded as a compositional data set the statistical treatment of which may be met with difficulties because of the so-called constant sum constraint. the nature of data (zero values in a number of cases due to the absence of some rock types) ruled out the most frequent way of solving the problem which uses the log-ratios (e.g. aitchison, 1986) so that initial matrix ill-conditioning was amended optionally, by dropping the surplus or “unnecessary” variable from the closed data set. the lithologic variable subtracted from the original six-variable data set is represented by the youngest rock unit – the plio–pleistocene and quaternary unconsolidated deposits of various types (mostly of freshwater, fluvial–lake origin) – which are the reworked older material of very heterogeneous composition, occupying large portions of the marginal south-eastern drainage basins. therefore, the supposedly small variance (effected by mixing) contained in the sixth variable was easily sacrificed for the necessities of untangling the compositional data problem. the remaining five lithological variables were deemed quite sufficient to faithfully reflect the main lithologic features of the study area liable for geochemical behaviour in the observed media. 6. results and discussion the results of regression analysis are described separately for each of the two experimental designs and displayed in tables 2 and 3. the columns in the tables represent the values of the coefficient of determination r2, and beta coefficients (β) for independent variables. tabulated data show a great variance between the values of r2 which range from 11% for strontium (areal) to 73% for magnesium (areal), both in stream and overbank sediments. better insight into the variations in each individual element, which reflect the average differences among specified rock units, can be gained by categorizing the r2 values into simple classes similar to those used for simple correlation coefficients: (1) <0.3 for no correlation; (2) 0.3–0.5 for weak correlation; (3) 0.5–0.7 for good correlation; and (4) >0.7 for strong correlation. thus one can more easily trace the degree to which the elements are explained by predictor variables if the two approaches, namely linear and areal, are compared. of the 26 elements reported in this work only p, sr and y have r2 values invariably less than 0.3, which means 208 geologia croatica 56/2 209peh & miko: impact of geomorphological variables in weighing the lithological influence... that more than 70% of their variation is not explained by the average differences between the lithologic units. to this group can also be added elements such as as, ti and nb whose residual variability may also exceed this value. their lithological origins are better mirrored in overbank material combined with linear proportions of map units, particularly in the case of titanium. the relationship between the stream and overbank sample media will not be discussed here at length because it has been thoroughly considered in an earlier work (peh & miko, 2001). here, it will suffice to say that the principal geochemical difference between the two sample media was perceived primarily in the presence of a higher content of the bulk of analyzed elements in the overbank sediment as well as in its greater homogeneity. this property certainly extends usefulness of the latter in explanatory purposes due to its greater inherent variability. here, we are basically concerned with the differences in variation explained by linearly and areally weighted bedrock lithology in a drainage basin. it must be noted, also, that regression designs were narrowed to the variations in geochemical content due to average differences in geological background. other contributing factors, such as scavenging by fe and mn oxides and hydroxides, influence of ph, or anthropogenic impact, were not considered. the effect of linear vs. areal proportions is most evident from the regression results summarized as the tabulated values of r2 (tables 4 and 5; figs. 5 and 6). the greater part of the analyzed elements fall within the two classes whether r2 was calculated from linear or form areal proportions, namely of weak (0.3–0.5), or good (0.5–0.7) explanatory potential, respectively. but, it is obvious that the variation of geochemical content is better explained by linear than by areal proportions of rock units, as the number of elements change their r2-class when the tables are cross-compared, with the higher values in the first case. this is particularly characteristic of ca and ti among major, and cr, zr, sc and ni among minor elements. explanatory potentials of nb and co are also considerably augmented while mg, interestingly, remains steadily associated to the areally defined bedrock lithology which presupposes the constant supply of dolomite material, spatially unconstrained because of its characteristic weathering pattern. the preponderance of a linearly over areally defined lithological imprint in the sample media is even more noticeable if the r2 values for the two linear areal el. r2 tckl pmkl fl lim dol r2 tckl pmkl fl lim dol fe 0.50 – 0.44 – ca 0.54 + 0.51 + mg 0.67 + 0.73 + + ti 0.24 0.26 – – al 0.49 – – 0.43 – na 0.52 – – 0.42 – k 0.45 – 0.41 p 0.14 0.20 + cu 0.37 + 0.30 + pb 0.63 + 0.63 + zn 0.45 + 0.47 + ni 0.64 – 0.41 co 0.55 – 0.48 – mn 0.47 0.45 as 0.24 + 0.23 + th 0.36 – – – – 0.40 – – – sr 0.13 0.11 v 0.50 – – – 0.41 – – la 0.35 – – 0.36 – cr 0.53 0.46 + ba 0.52 + 0.61 + zr 0.59 – – 0.58 – – y 0.26 – – – 0.26 – nb 0.42 – – 0.41 – sc 0.53 – – – 0.50 – – hg 0.31 + 0.43 + table 2 summarized results of two experimental designs for stream sediment data. legend: el. – element, r2 – goodness-of-fit, tckl – clastic sedimentary rocks of the tertiary period; pmkl – clastic sedimentary rocks of upper palaeozoic–triassic; fl – cretaceous flysch-like series; lim – limestones; dol – dolomites. 208 geologia croatica 56/2 209peh & miko: impact of geomorphological variables in weighing the lithological influence... experimental designs are represented as the difference which may be either positive or negative (r2 linear r2 areal). the diagrams (figs. 5 and 6) show the better fit of the linear aspects which in the case of overbank sediments is quite remarkable because only mg among major, and pb and hg among trace elements, are at variance with the general scheme. as a contrast, with stream sediments not only a smaller number of elements are better explained by the linear approach but also the positive r2 difference is generally much less (with the exception of ni and cu). thus, some extra minor and trace elements such as ba, zn and th tend to be areally better associated to lithology, while almost all others also reduce to some extent their affinity toward linearly defined bedrock units (cf. figs. 5 and 6). the overbank sediment is, as expected, a more contrasting background for discriminating between the two regression models. this is the result of the different fluvial dynamics which, even on a small scale, include local fluctuations either due to a low or seasonal variability in flow along the channel or to floods (paola, 2000). also the geochemical composition of the sediment flux cannot be separated from other aspects of processbased fluvial scenarios, particularly those related to morphodynamics. depositional history of the drainage basin sampling media reflects either a slow and steady aggradation processes, or catastrophic (flood-induced) redistribution of the previously (temporarily) deposited bedload. active sediment on the channel floor past any given spot along the channel is more or less balanced with stream transport capacity, having a limited range of supply, transport and deposition. overbank sediment, on the other side, originates from hazard events with increased water discharge, high average velocities, and high sediment discharges (gregory & walling, 1973) which affect the whole stream network upstream of the sampling site. furthermore, besides inundating the wash load over its banks this event may also result in episodic erosion of the channel floor and banks of the feeder streams throughout their length. relationship to source lithology the parent lithology as a source for various elements in alluvial media can be deduced from regression coefficients (β) given in tables 2 and 3. only the sign of significant β values is highlighted in corresponding lithological columns marking the increase or decrease linear areal el. r2 tckl pmkl fl lim dol r2 tckl pmkl fl lim dol fe 0.67 + 0.62 + ca 0.56 + 0.45 + mg 0.69 0.72 ti 0.56 – 0.45 – al 0.47 – 0.37 na 0.47 – 0.37 – k 0.48 0.43 + p 0.22 + 0.16 + cu 0.55 + + + 0.53 + pb 0.54 + 0.59 + zn 0.48 + + 0.42 + ni 0.59 + 0.42 co 0.70 + + 0.64 + + + mn 0.46 + + 0.38 + + as 0.46 + 0.38 + th 0.42 – 0.39 – sr 0.21 0.17 v 0.45 – 0.34 la 0.40 – 0.31 – cr 0.62 + 0.47 ba 0.55 + 0.53 + zr 0.57 – 0.48 y 0.21 0.16 nb 0.39 – 0.24 sc 0.51 – 0.40 hg 0.52 + 0.62 + table 3 summarized results of two experimental designs for overbank sediment data. legend: el. – element, r2 – goodness-of-fit, tckl – clastic sedimentary rocks of the tertiary period; pmkl – clastic sedimentary rocks of upper palaeozoic–triassic; fl – cretaceous flysch-like series; lim – limestones; dol – dolomites. 210 geologia croatica 56/2 211peh & miko: impact of geomorphological variables in weighing the lithological influence... in the share of the explanatory variables (rock units) to the regression model (elements). a number of minor and trace elements derive their origin from the clastic sedimentary rocks of the upper palaeozoic to lower and middle triassic age (pmkl). the β coefficients for this rock unit are always positive, signaling that (fe), cu, pb, zn, co, mn, as, hg and ba are hosted in these rocks mostly in the sulphide-rich layers or veins in the fine-grained sandstones. this mineralization is notable for the central parts of the samobor mt. (rudarska gradna stream) sometimes even in the form of small-scale siderite–haematite– sulphide ore bodies with chalcopyrite, cinnabarite and galena–barite paragenesis (šinkovec, 1971; šiftar, 1989). all these elements can be traced equally in both alluvial media, and following both approaches. the β coefficients are not necessarily positive when other rock types are considered. this is especially evident with dolomite bedrock to which most of elements, except ca and mg, are negatively associated. negative values denote the elements which are generally deficient within the relevant lithology, such as fe, ti, al, na, v, la, zr, nb and sc in dolomite (dol), th in the flysch-like series (fl), if statistically significant, as well as al, na, th, v, zr, nb and sc in the tertiary clastics (tckl). thorium is, interestingly, negatively related to all bedrock types where the β coefficients are significant, though its lithological origin r2 linear areal <0.3 ti, p ti, p as, sr, y as, sr, y 0.3–0.5 al, k fe, al, na, k cu, zn, mn, th, la, nb, hg cu, zn, ni, co, mn, th, v, la, cr, nb, hg 0.5–0.7 fe, ca, mg, na ca pb, ni, co, v, cr, ba, zr, sc pb, ba, zr, sc >0.7 – mg – – table 4 tabulated values of goodness-of-fit r2 for both regression models (stream sediments). r2 linear areal <0.3 p p sr, y sr, y 0.3–0.5 al, na, k ca, ti, al, na, k zn, mn, as, th, v, la, nb zn, ni, mn, as, th, v, la, cr, zr, sc 0.5–0.7 fe, ca, mg, ti fe cu, pb, ni, cr, ba, zr, sc, hg cu, pb, co, ba, hg >0.7 – mg co – table 5 tabulated values of goodness-of-fit r2 for both regression models (overbank sediments). fig. 5 linear vs. areal proportions of lithological influence in stream sediments: (a) major elements; (b) minor and trace elements. a b 210 geologia croatica 56/2 211peh & miko: impact of geomorphological variables in weighing the lithological influence... is accounted for by 42% at most. other elements which are also poorly explained by the variations in the rock types but show statistically significant betas must be pondered carefully. phosphorus, for example, is a major element falling within this group. not more than 22% of the variation in this element is due to differences between lithological units but, nevertheless, siginificant β values may appear which relate it positively to limestones (in overbank), or tertiary clastics (in streams). magnesium however, of all the elements is best explained by lithological effects (over 70%), albeit the regression coefficient for overbank are proved nonsignificant whether by the linear or areal approach. such examples must be regarded only as the case wherein the element has no preferential association with respect to parental rock and the sediment influx with mg-containing minerals comes in equal proportions from all rock types, not only dolomite (see tables 2 and 3). otherwise, mg in stream sediments is positively related to dolomites, even with limestones (where these occur interbedded with dolomites as carbonate rocks of secondary importance) which can be ascribed to the selective power of the streams precipitating the suspended load not far from the eroded reaches of the channel and valley sides. a characteristic relationship of a group of trace metals, such as cu, zn, ni, co, cr and mn to the limestone bedrock (table 3) gives rise to a longdisputed problem of the sediment supply from the limited weathering of “hard” rocks, particularly in carbonate terrains (durn, 1996; durn et al., 1999; miko et al., 1999). in contrast to the “soft” rocks (including dolomites) which are readily decomposed so that soil formation is not necessary for erosion (leeder et al., 1998), limestones predispose some kind of influx of weathered material from different geochemical surroundings. in the žumberak steep intermontane catchments the regolith which mantles the limestone bedrock is most probably of allochtonous origin, and the unrelated group of elements must have derived their origin from the different bedrock. as expected, all these considerations do not interfere with the stream sediments (table 2) as the finer silt–clay topsoil material with its trace element contents is easily dispersed in suspension and deposited as the overbank sediment downstream. besides, the linear approach is proved again as the more faithful regression model which gives emphasis to a limited channel reach as the main receptacle for drainage basin forms and processes. the cretaceous flysch-like series and tertiary siliciclastic rocks do not appear as a predisposed source repository for most of the analyzed elements. this is especially characteristic of the flysch-like series where almost all betas are rendered non-significant, while the latter repeats the scenario of correspondence between the low element content and stronger presence of pertinent lithology. the majority of elements, including al and na, are negatively regressed. the fact that in both linear (mostly) and areal (more rarely) approaches these elements readily show lower concentrations in stream sediment can, perhaps, be explained the other way round: by the scenario in which the streams running through the unconsolidated and easily erodible tertiary siliciclastic rocks easily wash away the finegrained particles containing clay minerals. none of the analyzed elements in overbank sediment is significantly related to these rocks, which may be indicative of their depositional history – the same way as the tertiary clastics represent older reworked material, so the recent alluvium represents the tertiary clastics (or both) recycled and mixed within the area where the latter occupy greater expanses of the žumberak region (on the border of the karlovac depression in the southeast). furthermore, a great number of elements in overbank sediment which show non-significant β values for each rock unit in both regression models may once again signal indifference of its geochemical composition to climatic or physiographic control on sediment production in late holocene times. fig. 6 linear vs. arial proportions of lithological influence in overbank sediments: (a) major elements; (b) minor and trace elements. a b 212 geologia croatica 56/2 213peh & miko: impact of geomorphological variables in weighing the lithological influence... 7. conclusions the two regression models were compared on the assumption that the geochemical composition of alluvial material is essentially derived from the bedrock lithology of a drainage basin. integration of drainage basin lithology with both stream sediment and overbank sediment geochemical data suites was carried out using the lowto medium-order mountainous catchment basins and their drainage networks in two ways: (1) as the area of influence occupying the whole basin upstream and upslope from the sampling site; and (2) the “line” of influence representing a narrow tract along all of the perennial streams which form the active stream network upstream and upslope from the sampling site. the most straightforward general result of these experiments is the one which underpins the linear approach as the more fitted model of the lithological influence on the analyzed sample media (88% vs. 62% of analyzed elements). this is explained by the stronger erosive and transporting power of the water which flows in the well defined channel network with respect to the unconcentrated surface runoff in the interfluvial area, coupled with the buffer effects of rich slope and riparian vegetation, which is characteristic of the žumberak heartland. a number of dry valleys in upper basin reaches also contribute to this, as their geomorphologically inactive bottoms considerably reduce the available area required for continuous sediment supply and transport of weathered material down to the lower parts occupied by perennial and intermittent streams. the other important regression results, which relate geochemical composition of alluvium to the source terrain lithology, can be briefly summarized as follows: – the low goodness-of-fit values for elements like p and sr indicate that their lithological origins are effectively screened by other factors not accounted for by the regression models; – mg is, as the best fitted element, steadily associated to the areally defined bedrock lithology (tectonically predisposed weathering pattern); – trace metals (cu, pb, zn, as, hg, ba) derive their origin from the palaeozoic and lower triassic siliciclastic rocks (pmkl) as indicated by significant positive beta values; – majority of elements do not display significant associations with certain lithological variables such as the cretaceous flysch-like series (fl) and limestones (lim); – negative element associations are typical for dolomites (dol) and tertiary siliciclastic rocks (tckl); – affinity of a group of trace elements – cu, zn, ni, co, mn and cr – for limestones indicates their allochthonous relation to bedrock. the regression results acquired in this admittedly restricted study indicate that the geochemical signature of drainage basin sediments grossly reflects their sourcing from the basin parent lithology, but the patterns of compositional variation are not easy to assess as these depend on a variety of processes. although the better fit of the “linear” model highlights the channel processes as a particularly responsible factor in compositional modifications, one needs a greater number of basin predictor variables for unravelling the specific geochemical behaviour of the analyzed elements. the results indicate the overbank sediments as the better recipient of multivariate geochemical supply signals from the study area. this will narrow future studies to the smallscale provenance analysis of alluvia with more detailed bedrock lithology and other variables included which will encapsulate all relevant local–regional geomorphological and other earth-surface processes responsible for its geochemical composition. acknowledgements this study was funded by the ministry of science and technology of the republic of croatia, project no. 01810106 – “the basic geochemical map of croatia”. their support is greatly appreciated. 8. references aitchison, j. (1986): the statistical analysis of compositional data.– chapman & hall, london, 416 p. babić, lj. (1974): razdoblje otriv–cenoman u žumberku: stratigrafija, postanak sedimenata i razvoj prostora [hauterivian to cenomanian period in the region of žumberak, northwestern croatia: stratigraphy, origin of deposits and palaeogeographic evolution – in croatian].– geol. vjesnik, 27, 11–33. bonham-carter, g.f. & goodfellow, w.d. (1984): autocorrelation structure of stream-sediment geochemical data: interpretation of zn and pb anomalies, nahanni river area, yukon–northwest territories, canada.– in: verly, g., david, m., journel, a. & marechal, a. (eds.): geostatistics for natural resources characterization. reidel dordrecht, 2, 817–829. bonham-carter, g.f., rogers, p.j. & ellwood, d.j. (1987): catchment basin analysis applied to surficial geochemical data, cobequid highlands, nova scotia.– j. geochem. explor., 29, 259–278. bukovac, j., šušnjar, m., poljak, m. & čakalo, m. (1983): osnovna geološka karta sfrj, 1:100.000, list črnomelj, l33–91 (basic geological map of sfry, geology of the črnomelj sheet).– geološki zavod zagreb and geološki zavod ljubljana (1972-1983), savezni geološki zavod, beograd. carranza, e.j.m. & hale, m. (1997): a catchment basin approach to the analysis of reconnaissance geochemical–geological data from albay province, philippines.– j. geochem. explor., 60, 157–171. dujmović, i. & bognar, a. (1995): some fundamental structural–geomorphologic characteristics of northeast 212 geologia croatica 56/2 213peh & miko: impact of geomorphological variables in weighing the lithological influence... part of žumberak mountain.– geograf. glasnik, 57, 21–35, zagreb. durn, g. (1996): podrijetlo, sastav i uvjeti nastanka terra rosse istre [origin, composition and genesis of terra rossa in istria – in croatian].– unpubl. phd thesis, university of zagreb, 204 p. durn, g., ottner, f. & slovenec, d. (1999): mineralogical and geochemical indicators of the polygenetic nature of terra rossa in istria, croatia.– geoderma, 91, 125–150. gregory, k.j. & walling, d.e. (1973): drainage basin form and process.– edward arnold, london, 450 p. hawkes, h.e. (1976): the downstream dilution of stream sediment anomalies.– j. geochem. explor., 6, 345–358. herak, m. & bukovac, j. (1988). the tectonic window of duralije in žumberak mt.– geol. vjesnik, 41, 231–236. hovius, n. & leeder, m. (1998): clastic sediment supply to basins.– basin res., 10, 1–5. jenson, s.k. & trautwein, c.m. (1984): definition of multivariate geochemical associations with pollymetallic mineral occurrences using a spatially dependent clustering technique and rasterized stream sediment data – an alaskan example.– symp. assoc. explor. geochem., reno nev., march 25–28, 1984, abstracts with program, 30. johnsson, m.j. (1993): the system controlling the composition of clastic sediments.– in: johnsson, m.j & basu, a. (eds.): processes controlling the composition of clastic sediments. geol. soc. am. spec. paper, 284, 1–19. kirkby, m.j. (1969): erosion by water on slopes.– in: chorley, r.j. (ed.): water, earth, and man. methuen & co ltd., london, 229–238. leeder, m.r., harris, t. & kirkby, m.j. (1998): sediment supply and climate change: implications for basin stratigraphy.– basin res., 10, 7–18. miko, s., durn, g. & prohić, e. (1999): evaluation of terra rossa geochemical baselines from croatian karst regions.– j. geochem. explor., 66, 183–197. montgomery, d.r & buffington, j.m. (1997): channel–reach morphology in mountain drainage basins.– geol. soc. am. bulletin, 109/5, 596–611. mrinjek, e. (1992): the bottom current sediments (contourites) in the upper cretaceous deep-water deposits in the northeastern part of žumberak (croatia).– geol. croatica, 45, 69–86. ollier, c.d. (1981): tectonics and landforms.– longman, london–new york, 324 p. owens, p.n., walling, d.e. & leeks, g.j.l. (1999): use of floodplain sediment cores to investigate recent historical changes in overbank sedimentation rates and sediment sources in the catchment of the river ouse, yorkshire, uk.– catena, 36, 21–47. paola, c. (2000): quantitative models of sedimentary basin filling.– sedimentology, 47 (suppl. 1), 121–178. peh, z. (1994): faktorski model kao izraz dinamike geoloških procesa na primjeru sjeverozapadnog dijela hrvatskog zagorja [dynamics of the geological processes reflected in the factor model of the northwestern part of hrvatsko zagorje, croatia – in croatian].– unpubl. phd thesis, university of zagreb, 162 p. peh, z. (1997): frequency distribution curves as an indicator of evolutionary trends in geomorphological systems: a case study from the northwestern part of hrvatsko zagorje (croatia).– geol. croatica, 50/1, 79–88. peh, z. & miko, s. (2001): geochemical comparison of stream and overbank sediments: a case study from žumberak region, croatia.– geol. croatica, 54/1, 119–130. pleničar, m., premru, u. & herak, m. (1975): osnovna geološka karta sfrj, 1:100.000, list novo mesto, l33– 79 (basic geological map of sfry, geology of the novo mesto sheet).– geološki zavod ljubljana (1963-1969), savezni geol. zavod, beograd. prelogović, e. (1969): neotektonska kretanja u području između orlice, samoborske gore i medvednice (neotectonic movements in the area between orlica, samobor and medvednica mts.).– geol. vjesnik, 23, 151–161. premru, u., ogorelec, b. & šribar, l. (1977): o geološki zgradbi dolenjske (on the geological structure of carniola).– geologija, 20, 167–192, ljubljana. rhoads, b.l. & cahill, r.a. (1999): geomorphological assessment of sediment contamination in an urban stream system.– appl. geochem., 14, 459–483. ritter, d.f. (1978): process geomorphology.– v.c. brown publishers, dubuque, iowa, 579 p. ritter, d.f. (1988): landscape analysis and the search for geomorphic unity.– geol. soc. am. bull., 100, 160–171. rose, a.w., dahlberg, e.c. & keith, m.l. (1970): a multiple regression technique for adjusting background values in stream sediment geochemistry.– econ. geol., 65, 156–165. salminen, r., tarvainen, t., demetriades, a., duris, m., fordyce, f.m., gregorauskiene, v., kahelin, h., kivisilla, j., klaver, g., klin, h., larson, j.o., lis, j., locutura, j., marsina, k., mjartanova, h., mouvet, c., o’connor, p., odor, l., ottonello, g., paukola, t., plant, j.a., reimann, c., schermann, o., siewers, u., steenfelt, a., van der sluys, j., de vivo, b. & wiliams, l. (1998): foregs geochemical mapping field manual.– geological survey of finland, espoo, 36 p. swennen, r., van der sluys, j., hindell, r. & brusselmans, a. (1998): geochemistry of overbank and high-order stream sediments in belgium and luxembourg: a way to asses environmental pollution.– j. geochem. explor., 62, 67–79. šiftar, d. (1989): starost evaporita i porijeklo sulfata u rudama kraj zagreba [the age of evaporites and the origin of sulphate at rude near zagreb – in croatian].– geol. vjesnik, 42, 59–64. šikić k., basch, o. & šimunić, a. (1977): osnovna geološka karta sfrj, 1:100.000, list zagreb, l38–80 (basic geological map of sfrj, geology of the zagreb sheet).– institut za geološka istraživanja zagreb (1972), savezni geološki zavod, beograd. 214 geologia croatica 56/2 šinkovec, b. (1971): geologija ležišta željezne i bakrene rude u rudama kraj samobora [geology of the iron and copper ore deposit at rude near samobor – in croatian].– geol. vjesnik, 24, 165–181. tuckfield, c.g. (1980): stream channel stability and forest drainage in the new forest, hampshire.– earth surf. process. landforms, 5, 317–329 velić, j. (1983): akceleracija vertikalnih tektonskih pokreta tijekom neogena i kvartara u zapadnom dijelu savske depresije [acceleration of vertical tectonic movements during the neogene and quaternary in the western part of the sava river depression – in croatian].– geol. vjesnik, 36, 225–265. weltje, g.j., meijer, x.d. & de boer, p.l. (1998): stratigraphic inversion of siliciclastic basin fills: a note on the distinction between supply signals resulting from tectonic and climatic forcing.– basin res., 10, 129–153. manuscript received october 10, 2001. revised manuscript accepted november 04, 2003. geol. croat. 50/2 1 119 120 1 zagreb 1997 pozdravni govor predsjednika organizacijskog odbora (welcome address of the president of the organising committee) v ladimir jelaska cijenjeni sku pc, postovana gospodo herak i obi tc­ ijski srodnici gospodina pro[csora milana heraka srda­ e nd vas pozd ravljam olvarajuc i ovaj znallstvcni skup, kojeg oddavam o u povoelu so-ie obljctni cc zivota akad emika milana i-ie raka, profcsora svcllcilista u zagrcbu. dragi profesore si?e1an vam i?odendan! roden 5. ozujka 1917 . u brasljcv ici, na zumbe­ rackom krsu mil an herak odrastao je u i11 nogobrojnoj obilciji , rand sickavsi raclne navike , ie smi sao za s logu j mcdusobno polpomaganjc, sto i11u je, u njcgoyoj kasni­ joj profcsionalnoj praksi, kada je bivao clanam ckipe iii rukovoditc ljcl1l , i11cntorqi1l iii savjclnikom , dalo prcdis­ pozicij u za polieanjc s ivaralackog ligodaja. tijckom kl as icne naobrazbc (zavrsio j e drugll klas icnu gimnaziju u zagre bll) nijc se opred ijelio ni za jeelnu slruku , ali u oelabiru sluelija prevladala je skionosl islrazivackom rnelll , a 10 jc nudio taelasnji filozofski fakultct s nekoliko kombinaeija prirodnih znanost i. student he rak bi o jc vise okrenut bolanickim precl­ metima, a njegov bli ski kolega domac geologiji pa su sllkladno svojim opredjcljc njim<1 podijc li li posao oko pra vljc nja biljcski na predavanjim a. t ijckom siudija b iva oelabran za clcmonslratora u geolosko-palconto­ loskom zavodu. to, ali i vise od toga nj egovo sudjclo­ vanj c ii tcrcn skim gcoloskim is trazivanjima u ckipi prof. salopcka, a zatim i uspjesno obavljc ni samostalni tc rcnski zadac i u lici, paklenici i kasnij c na medved­ nic i rezllitirajll time da mu gcologij a , koj a inacc nije bil a njcgovo primarno oprcdjc ljcnjc, postaje radom s lcccna sk lonost, koja i11u jc od rcclila s truc ilu blldu ­ enos!. na 10 prof. herak obicava reci " ".nc mora sc bas u ranoj mladosti oprcdijclit i za bllduec zvanjc." poslijc diplol11 c ( 1.941.) usavrsava ii l3ecll palcon­ tologijll iz cega jc rczultirao i njegov doktora t iz filo­ zofije ( 1943.) lemeljen na paleonloloskoj lezi. prvi dio s luzbovanja ( 1943-1952) proveo je 1i geo­ los ko-pal eollto los kom mll zcju u zagrc bu , a njcgova dcpal'llllcnt of geology and palaeontology. faculty of science. uni ve rs ity of zagreb. ui. kralja zvonimira 8 . hr i 0000 zagre b. croat ia. nastavnicka djelatnost pocinjc vee 1949. honorarnim pre­ davanjima iz palcobotan ikc i palcobiologijc na pmf-u. od 1952. do 1958. djellije na tehnickom faklilte lli na rudarsko m odjclu , najprijc kao docent , a za tim kao izvanredni profesor. obavljao je i duzllost stmjcsinc tog odjela. od 1959. pa do prcs tanka s aktivnol1l s lu zbol1l (1982.) prof. herak djellije na pmf-li. rcdovili je pro­ fesor od 1960. punih je 16 godina bio predslojnik geo­ losko-paleontoloskoga zavoda , a obnasao j c i procel­ nicku cluznost geoloskog oclsjeka i bio dckanom pmf-a (! 964 -66). poslijcdiplomski sludij iz gcologij e 1ilemc­ ijio je 1960. na pmf-u i predsjcdao (1969 -71. ) sve llc i­ li sllim oclborom za pos!ijecliplol1lski studij i znanstvc ni rad. uz to , biva i clanom mcdllnacionalnih i svj c tskih skupova , savjctnik dol1laci il i inozcmnih projcktan lskih inslituc ija tc vlaela nekih drzava. prof'esor milan he rak u svojcm j c dosadas njcm bavljcnju gcologijol11 objavio 222 razli cita nasi ova, od cega jc stotinjak znan stvenih raclova, 13 izdanja knji ga iz gcologije i pa leontolog ije te suautorska izdanja: "opc i prikaz zcmljc" i illcdunarodno izdanj c " kars t" (elsevier, 1972). te l11atski raspon njcgov ih radova veo­ ma jc s imk, a objavlji vani su 1i domae im i inozcmn illl casoplslllla. 1'a s irina nije znakovil3 samo u nj cgovom islraz i­ vackom i znanstvcnom bavlj e nju , nego i kada jc u pitanju njcgov nastavni rad. profcsorov postupak pod ­ razumijcva najprijc dobrc temelje, na kojc poslavlja harmonicnc okvirc, 1i koj e zatim smjes tava spcc ija­ li s ti cka istrazivanja i napokon postignulc rezultate . to j c polaz is tc naroc ito clos lo clo iz razaja kada mu j c postavljcna zahtje vlli1 zadaea obl ikovallj a novog prccl ­ i11 c ta za profil inzenjc r-gcologa na tadasnjcm rudar­ skoll1 odjc lu tchnickog fakuitcta, odnosilo kada se trazilo prakticna ijcsenja slozcn ih gco!oski h probl cma vezanih liz raz licite hidroe ne rge tskc objcktc . bnvcei sc lim pitanj ima llvida kol iko prakticna istrazivanja l110g u kori sno posluziti fundamcnla lnoj znallosti , jcclnako kao s to sc i dobri znanstvcni gco loski rezultali mogu this speech was presented at the scientific meeting dedicated to the 80th anniversary of the life of professor milan herak, held on march slh, 1997 in zagreb i .... u izravno primijenili u praksi. znati primijeniti geologiju, orudc jc kojim nas je profesor naucio rukovati, pokazu­ juci kako je i slozene geoloske pojavc moguce jedno­ slavno objasnili. uvjerio nas je da u terenska istraiiva­ nja valja uei s konccpcijom i polvrdivali ju opazanjima, ali kada geoloske pojave ostaju neobjasnjive tada morate mijenjati koneepciju, sugerirao je profesor. za sveslranu i plodnu djelalnost prof. herak dobio je brojna priznanja. od 1963. je dopisni, a od 1973 . redoviti clan akademije znanosti i umjetnosti. bio je i njczin potprcdsjednik (1975-78.), lajnik razreda za prirodne znanosli (1986-88.), clan predsjednislva, ured­ nik casopisa, te vodilelj odbora za krs i odbora za geoleklo niku. od 1977. je clan auslrijske, od 1991. siovenske, a od 1977. je bio clan srpskc akademije, do 1991., kada je otkazao c1anstvo. clan je t-trvatskog geo­ loskog drustva kojemu jc bio prvi tajnik, a poi om pred­ sjedn ik i pocasni clan. clan je brojnih inozemnih drustava. dobitnik je nagrade "ruder boskovic" (1968.), j"grade za iivolno dje lo (1976.) i spomen­ mcdaljc grada zagreba (1965.). odlikovan je ordenom racla sa zlatnim vijcncem (1961.) i ordenorn zasluga za narod sa zlalnom zvijezdom (1986.). '. geologw lroatlca ::.u/ .... u znak priznanja za znanstvena dostignuca vise je au10ra pocastilo prof. milana heraka imenovanjenl novih taksona na osnovi njegova irncna. ugledni skupe, 80. obljetnica ,ivola profesora milana heraka vazan je dogadaj 11 hrvatskoj geologiji. gcologija je, na nasern prostorll, relati vno mlacla znanost. pocetak sustavnog bavljenja geologijom vczan je uz duru pilara, koji je s ljedben icima utro neizbrisiv i prepoznatljiv trag. nastavljajuci pilarovom prtinom prof. herak opredijelio se temeljnim geoloskim zna­ njima i svojim znanstveno-nastavnim cljelovanjem pri­ donijeti bo ljern osvjetljavanju znanslvenih raskrizja, jasno naznacujuci rnoguce putove napretka. slijecliti ie putokaze nasa je zelja i zato odriavanjern ovog skupa, mi njegovi daci, zelimo profesoru milanll herakll iua­ ziti nase priznanje i zahva lnost. a kao trajan zapis danasnji cerno znanstveni dogadaj zabiljeziti u casopisll geologia croatica (vo l. 50/2), koji co u cijelosti biti posveccn ovome skupu. u nastavku prijepodnevnog programa sazeto cerna prikazati nastavno i znanstveno djelovanje profesora milana heraka. stevanovic.indd 179 � ab stra ct southeastern europe is known worldwide as classic karst terrain. in the alpine orogenic belt the karstifi ed carbonate rocks are either dominant, as in the dinarides, or widely distributed, as in the carpathian-balkans, hellenides or pindes. concerning karstic groundwater resources, this region is by far the richest in all of europe. some areas, such as southern montenegro, are characterized by an intensive and high precipitation affecting the water balance. in several countries in the region, water supply from karstic aquifers prevails. there are very large cities with populations of over a half million that depend on a water supply from karst aquifers. among them are fi ve capitals. tapping large springs is the traditional method of water supply in the region but the main concern is their unstable discharge regime. this is why many aquifer control projects have been prepared or proposed in the region, particularly in the mediterranean coastal area. unfortunately, few have been executed and completed. even some springs have been abandoned and water supply reoriented towards surface waters or alluvial aquifers. in contrast, with the tapping of the large sublacustrine spring bolje sestre in montenegro, the largest of the projects concerning regional water supply in karst is currently being implemented. some 1.5 m3/s of the water from the skadar basin will supply the coastal zone. it is expected that this project, essential for the national economy, will be completed in 2011. some other proposed large projects such as overseas karstic spring water transportation from albania to italy are still under evaluation. however, large and rich karstic reservoirs in this part of europe should remain a reliable source for water supply in the future despite some possible negative impacts of climatic variation. there is, in fact, the prospect of and interest in exporting and supplying water to both neighbouring and remote areas. keywords: karst, aquifer, water supply, groundwater control, se europe karstic sources of water supply for large consumers in southeastern europe – sustainability, disputes and advantages � zoran stevanović1 and romeo eftimi2 1department of hydrogeology/centre for karst hydrogeology, faculty of mining & geology university of belgrade, djušina 7, belgrade, serbia; (zstev@eunet.rs) 2 ita consult, tirana, albania; (eftimi@sanx.net) doi: 104154/gc.2010.15 geologia croatica 63/2 179–185 6 figs. zagreb 2010 geologia croaticageologia croatica 1. introduction when one talks about southeastern europe (see), the fi rst thing that comes to mind may be its beautiful sea, mountains and karst. the dinaric kras in the central part of the see is a typical area for dissolution landforms and aquifers; the regional names kras, crasso, germanicised as “karst”, are now applied to modern and palaeo-dissolution phenomena worldwide, thanks mostly to jovan cvijić and his numerous followers (ford, 2005). exploration and utilization of karstic waters is an ancient art in the area. for example, 11 long aqueducts delivered more than 13 m3/s of water to ancient rome from distances geologia croatica 63/2geologia croatica 180 ranging from 16–91 km (lombardi & corazza, 2008). several water supply systems from that time have been completely reconstructed but still use the same springs and pipeline routes. some “modern” water systems constructed in the 19th century still function perfectly and deliver pure karstic water over a long distance, as in the case of vienna. see is one of the most water-rich regions of the world, but due to its specifi c water regime and the behaviour of the karst, the local population often suffers from water shortages. for this reason karst and its features are still attracting scientists, particularly hydrogeologists and karstologists, but also engineers searching for an optimum solution to tapping and controlling karstic groundwater (fig. 1). 2. current groundwater supply from karst in the alpine orogenic belt, the karstifi ed carbonate rocks are either dominant, as in the dinarides, or widely outcropping, as in the adjacent carpathian-balkans, hellenides or pindes. the water supply from the karst is dominant along the coastal area and in the islands where karstic waters are commonly even the sole resource. in the continental part, numerous large karstic springs along the foothills of karstic massifs are also regularly tapped. at present, fi ve capitals of the see (vienna, sarajevo, tirana, skopje and podgorica), and numerous large towns utilize karstic waters for drinking purposes, and rarely for industrial purposes or for irrigation (stevanović, 2010a). within the offi cial eu boundaries of the see region, vienna has the largest water supply system based on karst waters (figs. 2a,b). it serves some 1.7 million inhabitants and the yield covers around 97% of the water demands. the system consists of two major gravity pipelines, 130 and 200 km long (drennig, 1973). the fi rst pipeline was completed in 1873, the second in 1910. the long concrete tunnels and channels provide an average yield of 4.5 m3/s from several tapped springs that drain catchments in the alps of around 600 km2. the water is of excellent quality; only chlorination is required, generally for cleaning the distribution pipes. sarajevo gets part of its necessary waters from the vrelo bosne springs. the discharge of this group of springs that drain a rich triassic aquifer of the igman mt. is in the range of 1.4–24 m3/s (čičić & skopljak, 2004). currently, 0.4 m3/s is an average discharge directly tapped from the springs while the water master plan counts on roughly an additional 1 m3/s to be used by the intake in the open course located downstream (kovačević & lončarević, 2003). the albanian capital tirana obtains its water in part from the source that drains a triassic and jurassic karstic fi gu re 1: main branches of the alpine orogenic system and locations of the springs discussed here (modifi ed from stevanović, 2010a). fi gu re 2: kaiserbrunn spring tapped for viennas water supply. a) original sketch from waterworks museum (left) and b) current view (right). a b stevanović and eftimi: karstic sources of water supply for large consumers in southeastern europe – sustainability, disputes and advantages geologia croatica 181 1. the main concern in karst is an unstable groundwater regime as a result of an uneven rainfall distribution throughout the year. many consumers in the region fi ght every year to ensure a water supply during low water periods (summer and autumn). the problem is growing in large urban areas: migration of the population towards the cities, their fast urbanization, and the growth of industry in the 20th century has caused an increase in the number of tapped springs. in addition, during the summer seasons, the number of consumers and demands signifi cantly increase along the coastal area. during the last decade, tourist expansion and population density are particularly evident in montenegro and in albania, and the problem of water shortage has become the main obstacle to further development. concerning karstic groundwater resources, this region is by far the richest in all of europe. some areas, such as southern montenegro, are characterized by very high specifi c yield, on average over 40 l/s/km2. milanović (2005) stat ed that “only through three huge springs along the neretva valley and adriatic coast (buna, bunica and ombla) and a few spring zones in the kotor bay more than 150 m3/s, average annually, are being discharged in the adriatic sea directly, or indirectly through the neretva river”. due to limited and unstable discharge, some springs have been completely abandoned and the water supply reoriented towards surface waters or other available sources such as alluvial groundwater. some others, such as the aravissos group of springs, are still in use, but the water supply system of thessaloniki was fi rst expanded by groundwater abstraction from the alluvial aquifer of the axios basin and since 2003 has been supplemented with the water of the aliakmon river (spachos et al., 2006). similarly, many wells were drilled near tirana, podgorica and sarajevo in an attempt to fi ll the gap between demands and available waters. 2. the problems of water quality in the see karst centre on two main concerns: aquifer vulnerability and high risk of pollution and intrusion of salty water. karstic aquifers are highly precious but also extremely vulnerable sources. the problem is greater along the coast due to the many pollutants present there, untreated wastewater, and improper disposal of solid wastes. fast-growing tourist areas in montenegro and in albania are particularly in danger, and during the last few years systematic action to construct modern regional municipal landfi lls has started. in order to mitigate problems of rapid urbanization and uncontrolled pollution, biondić & goatti (1984b) proposed four sanitary protection zones and many mitigation measures for the water source of rijeka. similarly, the four protection zones in the recharge area of the rižana spring were defi ned based on detailed hydrogeological research and tracer tests (krivic et al., 1989). bensi et al. (2005) stated that the water supply of the trieste region from the timavo springs is compromised by anthropogenic and industrial development and today represents only an emergency water resource (an alluvial aquifer is used as the main source of water supply). the coastal uji i ftohte spring near vlore, issues 2.5 m3/s on average but its high quality water is threatened by polluaquifer of the mali me gropa plateau. since world war ii the two main springs, selita (0.24 to 0.86 m3/s) and shemria (0.45 and 1.50 m3/s), have been tapped for the city (eftimi, 1971), while a large reservoir has been constructed (eftimi, 1998) downstream from the third important spring buvilla, issuing from dajti mt. the mareza spring (2.0–10.0 m3/s) in the skadar basin is the main source of the montenegro capital city of podgorica. this group of typical ascending springs discharges at the 2 km long, point of contact between the cretaceous limestone and limnoglacial sediments of the basin (radulović, 2000). the capital of fry of macedonia, skopje, obtains most of its drinking water from a karstic aquifer formed within palaeozoic marbles. rašče spring situated on the vardar river bank is characterized by a relatively stable discharge regime (qav=2.5 m3/s). according to the results of tracing tests and isotopic analyses, the main recharge of rašče water is from a porous aquifer of the upstream pološko polje and percolated vardar water. along the adriatic, ionian and aegean coasts, almost all cities and tourist centres consume karstic groundwater. perhaps the most famous and the largest spring on the northern italian coast, timavo, with an average discharge rate of 30 m3/s, supplied water to trieste in the past. rižana near koper is the main source for supplying water to the slovene coastal zone. its average discharge is 4.3 m3/s (qmin= 0.03 m3/s, kolbezen & pristov, 1998). the zvir group of springs were tapped at the end of the 19th century to supply water to rijeka, the largest croatian port. the discharge varies between 0.6 and 3.0 m3/s (biondić & goatti, 1984a). jadro spring is the main source for the water supply of split. the average minimum discharges of jadro during the recession period are 3–5 m3/s, while maximum discharges are often over 50 m3/s (bonacci, 1987, denić-jukić & jukić, 2003). ombla spring is the largest permanent karstic spring in the south adriatic. it supplies the city of dubrovnik. since the completion of the trebisnjica hydro-electric system and the regulation of this biggest sinking river in europe, the average discharge of ombla has been reduced from 34 m3/s to 24 m3/s. however, the minimum discharge (2.3 m3/s) is not affected by the applied measures (milanović, 2006). in the continental part of the region, that is in serbia, romania and bulgaria, there are several large cities that depend on karst aquifers and their discharge regimes (stevanović & filipović, 1994). among them are niš, pirot, craiova, trgu jiu, turnu severin, constanza, gabrovo. 3. main problems of karstic water utilization there are several problems encountered when tapping and utilizing karstic groundwater in the see. they can be classifi ed into two major groups: 1. quantity limitation 2. quality deterioration. geologia croatica 63/2geologia croatica 182 tion from the new urban area constructed upstream. there are a few cases where large springs have been impounded and devastated by artifi cial reservoirs. in fact, karstic aquifers remain to feed those reservoirs, but the quality of the water has signifi cantly deteriorated (fi rst of all due to eutrophication). therefore, the destiny of the dumanli spring in turkey, one of the largest springs in the world, is also shared by several springs of the see: buvilla for tirana, vrela trebišnjice in herzegovina (submerged by bilećko lake), vrutačka vrela in serbia (impounded by vrutci reservoir), etc. the risk and intensity of salt water intrusion depends on: the source location and altitude and the extraction rate. as a result of intensive and fast karstifi cation, epirogenic movements and the rise in sea level by about 100 m since the last glacial phase, many springs are discharging at or below the existing sea level. in boka kotorska bay alone there are three very large springs that discharge over 100 m3/s after heavy rains, but almost dry out during the summer months (sopot, spila risanska and ljuta). the hydraulic mechanism of the sopot spring is particularly interesting. the spring cave has been explored by speleologists and divers to a depth of 35 m and length of about 380 m of both dry and fl ooded channels (milanović s., 2005). during the hydrological maximum, when the karst channel of the sopot submerged spring is unable to accept all infl owing water, a huge amount of water erupts from the cave, and the groundwater level rises to over 40 m above sea level (asl). the lower caverns continuously discharge groundwater to the sea bed. the conducted analyses determined that, during the low-water period, even at the most remote inland point (500 m from the sea), there is an extensive intrusion of seawater. therefore, despite the water abundance all along the edges of the boka kotorska the population of this area suffers from an inadequate supply of freshwater. similarly, the problem of saline intrusion or mixing fresh and sea water exists on many islands. the almiros spring near heraklion on crete is a typical example of saltwater intrusion. groundwater drains at an elevation of 5 m asl, but the deeper part of the aquifer is under the strong infl uence of saltwater percolating from the estavelle identifi ed at a depth of 25 m on the sea fl oor. cl ion can reach 6 g/l. the problem is even greater if the constructed intakes enable pumping or there are drilled wells nearby. under such circumstances any forced extraction could lead towards increased water salinity. it is thus preferable to have: a local barrier that diverts groundwater high enough over sea level; or natural discharge suffi cient to cover demands when no artifi cial intervention is needed. few large springs along the coast are located far enough from the sea or at higher altitudes. among the biggest of such springs are jadro near split, at 35 m asl at the contact with eocene fl ysch sediments, and blue eye, part of the bistrica group of springs in albania (syri kalter, fig. 3) discharging at elevations of 152–157 m asl. 4. karst aquifer control in order to mitigate water shortages in the see many karst aquifer regulation projects have been prepared or proposed. most of them aim to control discharge by constructing underground reservoirs. unfortunately, only a very small number of these projects have been executed. there are many reasons for this, but generally it is due to the greater cost of the exploration of karst groundwater and its lower predictability in terms of fi nal outcomes. although the extraction of karstic waters by classical intakes is regularly much cheap er than other sources used, the cost of underground reservoirs is not low and alarms potential investors. this is the main reason why some good ideas, such as reservoirs proposed to control karstic springs along the metohija basin edge (beli drim, istok, vrelo), have never been realized (perić et al., 1980). the ombla reservoir is one of biggest such proposed projects for which complex research has been undertaken (milanović, 2006). in the continental part of the region, hydrogeological surveys undertaken from 1987–1997 have made possible the construction of several successful systems for the artifi cial control of karst aquifers in serbia (stevanović, 2006, stevanović et al., 2007). the largest system for aquifer control was constructed as part of the regional water system “bogovina“ in eastern serbia. similarly, a solution with pumping wells has been applied to the water supply of contanza (romania), a black sea coastal resort and port. the battery of drilled wells taps the semi-confi ned karstic aquifer in jurassic limestones. a solution that combines pumping from the siphon and drilled wells has been applied at the vauclusian modro oko spring (krupac source), one of the sources for the water supply of niš (the second largest city in serbia). the regional system for the montenegro coast is now under construction and should be completed in 2010 or 2011. the system is planned for a maximum capacity of 1.5 m3/s in two stages. the total pipeline length is 140 km. the water will be tapped from one of the numerous sublacustrine karstic springs of skadar lake – bolje sestre (qmin = 2.3 m3/s). the fi gu re 3: blue eye vauclusian spring, albania. stevanović and eftimi: karstic sources of water supply for large consumers in southeastern europe – sustainability, disputes and advantages geologia croatica 183 water discharges through several registered points near the shore (stevanović et al., 2008). the problem of tapping an impounded spring will be solved by two means: the coffer dam and pumping shaft (located nearby the most productive drilled borehole). the basic idea was to tap the water before it reaches the submerged discharge points (figs. 4, 5). simply, this should be the best way to avoid mixture with waters of the lake and the threat of groundwater quality deterioration. the fact that the pumping capacity from the shaft-well must not result in signifi cant drawdown and exaggerate lake water intrusion has been taken into consideration. the concrete elliptical structure – coffer dam will cover an area of some 300 m2. the concrete dam will have a rubber gate spillway, and its task will be both to evacuate untapped water, and to prevent infl ow of lake water. in fact, the mobile gate has the form of a wide tube made from special resistant rubber that can be filled with compressed air (stevanović, 2010b). 5. prospectives of karst groundwater sustainable use the karstic aquifers will certainly remain the main source for water supply for a long time in most of the see. for the last several years we have been witnessing interest in large scale projects, and the export of good quality karstic waters to remote areas has increased. the options of water tankering or construction of overseas submarine pipelines to remote destinations has been discussed informally but openly at the conferences. such an idea to tap unutilized waters on the albanian side and transfer them over the otranto channel to the adriatic sea which divides the puglia region in italy from albania fi gu re 4: coff er dam and water treatment plant of the bolje sestre source. fi gu re 5: preparatory works for the foundation of a coff er dam at bolje sestre spring (stevanović, 2010b). fi gu re 6: the scheme for the trans-adriatic water project. legend: 1. spring; 2. city; 3. reservoir; 4. pipeline; 5. state boundary. geologia croatica 63/2geologia croatica 184 (at the closest, a distance of 85 km), has been seriously proposed and evaluated. out of an average yield of 18 m3/s, distribution of 4 m3/s is proposed from the blue eye – bistrica group of springs. this proposed system comprises three main sections: albanian territory; submarine section in the adriatic sea; and the italian territory (fig. 6). there are still many steps that have been undertaken for more rational utilization and sustainable development of karstic aquifers in the see. two essential ones are balancing and monitoring resources. for the fi rst, interdisciplinary and comprehensive research programs should be undertaken in many countries of the region. this is particularly important for those in coastal areas where many underground fl ows towards the sea are still unidentifi ed. new investigation techniques and sophisticated instruments should be used together with classic methods such as diving, remote sensing, tracing, geophysics, drilling, and hydrochemistry. secondly, monitoring is a basic precondition for any environmentally safe water management. discharge of many large springs or groundwater table fl uctuations in the region are still unknown. for example, no single observation borehole for permanent measurements exists along the adriatic coast from dubrovnik to saranda. without essential historical data it would not be so easy to discuss the issue of the impact of climatic change on the groundwater. 6. conclusion water management (including transboundary), monitoring and control of karst aquifers, and protection measures against the pollution of karstic surfaces are the most important aspects that require careful study in order to ensure the sustainable development of the see karst environment. diffi culties in karst water resource management represent the main and real reason for possible confl ict when they are internationally shared (bonacci, 2008). this is particularly important in this region where almost no single river basin is exclusively domiciled. furthermore, many large springs are characterized by having their catchment in one country and the drainage zone in another. the former yugoslavia is at the centre of the balkans and south east europe, where have recently ceased, and, new states and boundaries have been created. this has given rise to many questions regarding common and optimal water strategy in the region. however, during the last two or three years, many initiatives and concrete actions have been undertaken and now provide an optimistic ambience for future work and cooperation. references bensi, s., casagrande, g., cucchi, f. & zini, l. (2005): vulnerability of karst aquifers related to the construction of a railway tunnel-applied case study in the karst of trieste (ne italy).– in: stevanović, z. & milanović, p. (eds.): water resources and environmental problems in karst-cvijić, 2005, spec. ed. fmg, belgrade, 691–695. biondić, b. & goatti, v. (1984a): la galerie souterraine “zvir ii” a rijeka (yougoslavie).– in: burger, a. & dubertret, l. (eds.): hydrogeology of karstic terrains: case histories. intern. contrib. to hydrogeology, vol 1, iah, verlag heinz heise, hannover, 150–151. biondić, b. & goatti, v. (1984b): sanitary protection zones of fresh water springs in the community of rijeka (in croatian).– proc. of viii yugoslav. symp. of hydrogeol. and eng. geol., budva, 1, 281– 289. bonacci, o. (1987): karst hydrology with special references to dinaric karst.– springer verlag, berlin, 184 p. bonacci, o. (2008): challenges in transboundary karst water resources management.– proceedings of iv transboundary water management conference, cd, session 1/2, thessaloniki, 2008. čičić, s. & skopljak, f. (2004): geological and hydrogeological conditions of vrelo bosne catchment area (in bosnian).– voda, sarajevo, 37, 4–10. denić-jukić, v. & jukić, d. (2003): composite transfer functions for karst aquifers.– j. hydrol., 274, 80–94. drennig, a. (1973): die i. wiener hochquellenwasserleitung. magistrat der stadt wien, abteilung 31 – wasserwerke, wien, 303 p. eftimi, r. (1971): discharge regime of selita spring (in albanian).– permbledhje studimesh, 2, 65–76. eftimi, r. (1998): some data about the hydrochemistry of karst water of dajti mountain (in albanian).– studime gjeografi ke, 11, 60–65. ford, d. (2005): jovan cvijic and the founding of karst geomorphology.– in: stevanović, z. & mijatović, p. (eds): cvijic and karst. spec. ed. board on karst and spel. serb. acad. of sci. and arts, belgrade, 305–321. kolbezen, m. & pristov, j. (1998): surface streams and water balance of slovenia.– “mop: hidrometeorološki zavod rs,” ljubljana, 98 p. kovačević, s. & lončarević, m. (2003): long-term water supply of sarajevo canton (in bosnian).– voda, sarajevo, 35, 4–9. krivic, p., bricelj, m. & zupan, m. (1989): podzemne vodne zveze na področju čičarije in osrednjega dela istre (slovenija, hrvatska, nw jugoslavija).– acta carsologica, 18, 265–295. lombardi, l. & corazza, a. (2008): l’acqua e la città in epoca antica.– in: la geologia di roma, dal centro storico alla periferia, part i, memoire serv. geol. d’italia, vol lxxx, s.e.l.c.a, firenze, 189–219. milanović, p. (2005): water potential in southeastern dinarides.– in: stevanović, z. & milanović, p. (eds): water resources and environmental problems in karst – cvijić 2005, spec. ed. fmg. belgrade, 249–257. milanović, p. (2006): karst of eastern herzegovina and dubrovnik littoral.– asos, belgrade, 362 p. milanović, s. (2005): hydrogeological characteristics of some deep siphonal springs in serbia and montenegro karst.– environ. geol. 51/5, 755–759. perić, j., simić, m. & milivojević, m. (1980): an idea to storing part of beli drim water within underground reservoirs for water supply and irrigation of metohija (in serbian).– transactions of fmg, belgrade, 22, 251–292. radulović, m. (2000): karst hydrogeology of montenegro.– sep. issue of geological bulletin, vol. xviii, spec. ed. geol. survey of montenegro, podgorica, 271 p. spachos, t., voudouris, k., drosos, d., dimopoulos, g. & soulios, g. (2006) groundwater levels fl uctuation in aquifer systems of borehole fi elds of thessaloniki waterworks.– proc. of 10th pan-hellenic sci. cong., xanthi, on cd, session 13.4. stevanović, z. & filipović, b. (1994): hydrogeology of carbonate rocks of carpatho – balkanides.– in: stevanović, z. & fi li pović, b. (eds.): ground waters in carbonate rocks of the carpathian-balkan mountain range, spec.ed. of cbga, allston, jersey, 203–237. stevanović and eftimi: karstic sources of water supply for large consumers in southeastern europe – sustainability, disputes and advantages geologia croatica 185 stevanović, z. (2006): state of art and perspectives of artifi cial recharge in groundwater supply of large cities of carpathian-balkan region.– proc. of 18 cong. of cbga, belgrade, 602–605. stevanović, z., jemcov, i. & milanović, s. (2007): management of karst aquifers in serbia for water supply.– environ. geol. 51/5, 743–748. stevanović, z., radulović, m., puri, s. & radulović, mi. (2008): karstic source bolje sestre – optimal solution for regional water supply of montenegro coastal area.– rec. de rapp. du com. pour le karst et spéléologie acad. serbe des sciences et des arts, belgrade, 9, 33–64. stevanović, z. (2010a): major springs of southeastern europe and their utilization.– in: krešić, n. & stevanović, z. (eds.): groundwater hydrology of springs: engineering, theory, management, and sustainability, elsevier inc., 391–412. stevanović, z. (2010b): intake of the bolje sestre karst spring for the regional water supply of the montenegro coastal area.– in: krešić, n. & stevanović, z. (eds.): groundwater hydrology of springs: engineering, theory, management, and sustainability, elsevier inc., 459–480. manuscript received december 27, 2009 revised manuscript accepted march 07, 2010 available online may 31, 2010 geologia croatica 63/2geologia croatica 186 geol. croat. i 50/1 i 5 2 figs. i pi. zagreb 1997 valvasoria carniolica n.gen. n.sp., a triassic worm from slovenia tea kolar-jurkovsek and bogdan jurkovsek key words: valvasoria carlliolica n.gen. n. sp., trias­ sic, fossil worm , nematoda, sipuncu lida, slovenia. abstract carnian limestones exposed from mojslrana to trig lav (ihe high­ est slovcni an mountain). arc very important biostraligraphicajly. and cspccin lly for the palaeogeog raphic interpretation of ihe upper trias­ sic. outcrops can be traced in the vrain valley ex tendi ng in ii narrow be ll severa! kilometres in a no rt h-eas tward eastward direc ti on. a very quiet deposil ional environment, with reducing conditions at the sea noor, pcrmiucd the preservation of soft-bodied animal s. \lall'tlso­ ria c{lrn;olica is a new genus and specics. ii has a cy lindri cal body with an cxpanded antcriormosi ponion. the systematic position of v(lii'(lsor;a is unknown, however il might be related to nematoda or sipunculida. 1. introduction the strat igraphi c profi le ex posed in the vrala val ­ ley (fig. i) has been known to palacon to logisls from the beginning of the 20th century, when kittl ( 191 2) collected numerous well preserved specimens of !-ia/o­ bia clfallax mojsisoy ics and h. telleri kittl. on the bas is of these biva lves he determined the age as upper carnian or middl e norian. several palaeontolog­ ica l studies of these pelag ic limcstones were performed more recen tl y (j urkoysek, 1984; ramoy s, 1984, 1985; kolar-jurkoysek, 1991) and the conodont fauna (po/ygj/alh iforlllis-a.z.) establ ished a carni an age (kolar-jurkoysek, 1991). during geological mapping fo r the basic geological map of the beljak (y illach) and pontcbba sheet (jurkoysek, 1987a, b) several excellently preserved fos sils in the vrata valley have been collected, amongst which thc most important is an 84 cm long skeleton or a birgeriid fi sh (jurkoysek, 1984; jurkoysek & kolar-jurkoysek , 1986). decapod crustaceans :kolar-jurkoysek, 1991; jurkoysek & ko­ lar -jurkovsek, 1992), c ranial bones of sall r ­ ;ehlliys, and the inarticulate brachiopod discillisea have liso bcen fo und together with the new fossi l worm va/­ 'asoria eamioliea. nsti llit za gcologijo , geolchlliko in geofizi ko. dimiceva 14, slo1000 ljubljan;t, slovenia. 2. taxonomic description phylum, class, order a nd family uncerta in genus valvasoria n.gen. type species: valvasoria carnioliea n.sp. diagnosis: body cylindri ca l, unsegme nted, wit h ex panded an terior end, covered by a smooth and th ick cllticle. etymo logy: this gen us is named in honour of johann weikhard (janez yajkard) yalvasor, the carnia­ lian polymath, for his exceptiona l contribution to the knowledge of s lovene natural and na tio nal heritage. the fossil was d iscovered 011 the 300th anniversary of his death. range a nd occurrence: carnian stage, upper tri ­ assic of slovenia. valvasoria carlliolica n. gen., n. sp. diagnosis: as the generic desc ription. etymo logy: species nam e refers to carniola, the latin name of a foffner prov ince, today part of slove­ ilia. holotype: bj 1286 (pi. i, figs. la, b). paratypes: bj 1287 (pi. i, figs. 2, 3, 4), bj 1419. repository: palaeonto logical collection of bogdan lurkovsek, dol pri ljubljani , s loven ia, registered at the s iovenian museum of natural hi story , ljubljana; the col lec ti on has been declared a monument by the slovcn ian minis tl), of culture. type local ity: kozja dn ina in the vrata yalley, slovenia (rig. 2). horizon: carnian stage, upper t riassic. description: body s lender, cy lindrical; segment a­ tion not visible. an te ri or part of body narrow with width graduall y increasing posteriorly (min. w idth 1.5 mm , max. wicli h 5 mm ). an terionnost part marked by expanded structure and by a constriction behind it. pos­ terior par! or body mi ssing, preserved part 121 mm long. t he body is covered by a thick cuticle. in section, the lamellar structure of the cut icle is clearly visible (pi. i, fig. 4). the external surface of the c liticle appears to be smooth. in the paratype, small pores arranged in par2 geologia croatica 50/1 a -..... a u s t '-'-j''-'-' r·/· .... · ........ . -. if " l ai?' italy . <j~ sava d. 4 '-• ./ ......... ...,. r $!j kronjska olirlko v 4 " .~~ goro "'~ """\ r .""\....ja..§ -.l.",",'v\.. mojstrana .te; . 'j.q..~'?: jesenice '<. / . c. tflgla';' 6 za63 4 bohinjsko a jf>zero (iakt') bi~j5ko a jeuro (lakeo) 'l?' l p s .~a ._ . ./""..( .h ~-.,..i ~ \ f>. ,-n. gohifljka savq ! ':> c~ 'c.. ~. l s'j . ,.. !"" ........ voj erg 0 5 10 km , , , it-~ massive limestone (norian) ~ bedded and platy limestone 1+;] limestone with chert c. fossillocalily ~ valvasoria n.gen.n.sp. "til ammonoids 'if crustaceans tt ± +1 marly limestone 0< fish allel transverse and oblique lines arc seen under elec­ iron microscopy. in some places, two pores unequal in size appear closely together (pi. 1, figs. 2, 3). the inter­ nal surface of the cuticle shows a relief structure, which can be observed in traces (partly shown on pi. j, fig. 4). in the middle part of the preserved holotype body annu­ lalion can be observed. it is represented by five circular belts approximately 0.1 mm wide. distances between belts are 0.5 mm and 1 mill. the bells are colllposed of lon gitudinally arranged altcrnating fine ridges and grooves. fig. 2 kozja dnina, the type-locality of va{mmria camiolica n.gcn. n.sp. 20 m 10 o fig. i geographical sketch (a), and simplified strat igraphic co lumn (b) or tile carnian beds containing val­ i'asoria at kozja dnina in the vrata valley, slovenia. remarks: the relationship of valvasoria 10 other taxa is not clear. elongated, son-bodied animals ("worms") are classified into several phyla. classifica­ tion of recent worms is based on their soft-part anatomy and molecular data. the correct classification of many exlinct genera of worllls is difficult, even when the soft pal1s of the body are preserved_ therefore their assigne­ ment to higher taxa is as yet ten tative and subject to future revision (howell, 1966). the systematic position of valvasoria is unknown, however it might be related to the nematoda or sipun­ culida. representatives of both groups are characterized by a worm -shaped, unsegmented body. nematoda ( roundworm s) arc free-living or parasitic , threadlike aschelminthes known from virtually every marine, fre sh water and terrestrial habitat. thei r pharynx is modified for sucking and in some mcmbers (order araeolamoidea) there are lip excresecnces (hyman, 1951). sipunculans are benthic and exclusively marine. the sipullculid body is divisible into a trunk and a retractiblc introvert bearing the mouth and feeding ten­ tacles (brusca & brusca, 1990). in both groups, the body is covered by a cuticle secreted by the epider­ mis. the nematode cuticle surface is usually smooth, whercas the sipuneu lid body often bears fine cuticular structu res. the cuticle of many modern nematodes is ringed or marked with longitudinal ridges and grooves kolar-jurkoviick & jurkovsek: i'alm.l'o/'ia camiolica n.gen. n.sp .. a triassic wonn from slovenia (brusca & brusca, 1990). the epidermis of both groups contains unicellular glands in free-living nema­ todes, as well as illultieellular glands in sipuneulids. acknowledgements the authors arc indebted to dr. b. sket (universi­ ty of ljubljana) for his helpful and stimulating discus­ sions and manuscript review. we also thank drs. a. seilacher (university of tubingen) and s. con­ wa y morris (university of cambridge) for critica l­ ly reading the manuscript. dr. j. rode is acknowl­ edged for his photographic expertise (sem photographs pi. j, p igs. 2, 3,4). this research was supported in part by a grant from the siovenian ministry of science and technology to the institute of geology, geotech­ nics and geophysics. 3. references brusca, rc. & brusca, g.l. (1990): inverte­ brates.sinauer associates inc., sunderland , massa­ chusetts, 922 p. howell, b.f. (1966): worms.in: moore, r.c. (ed.): treatise on invertebrate paleontology, part w, miscellanea. geol. soc. america & univ. kansas press, boulder and lawrence, w144-wi77 . hyman, l.h. (1951): the invertebrates. acantho­ cephala, aschelminthes and entoprocta. the pse­ udocelomate bilnteralin. volume iii.mcgraw-l-iill , new york, toronto, london, 572 p. jurkoysek, b. (1984): najdba 210 milijonov let stnrega ribjega okostja.proteus, 47/1, 23-26, ljub­ ljana. jurkoysek, b. (1987a): osnov na geoloska kart a sfrj 1:100.000, lista beljak in pontebba.zvezni gcoloski zavod, beograd. jurkoysek, b. (1987b): osnovna gcoloska karta sfrj 1:100000. talmac listov beljak in pontebba.­ zvezni gcoloski zavod, beograd, 59 p. jurkoysek, b. & kolar-jurkoysek, t. (1986): a late triassic (carnian) fish skeleton (fami ly birgeriidae) from slovenia, nw yugo­ slavia.n. jb. geol. palaonl. mh., 8, 475-478 . jurkoysek, b. & kolar-jurkovsek, t. (1992): fosiji v sloveniji.didakta, radovljica, 72 p. kittl, e. (1912): materialen z ll einer monographic der halobiidae und monolidae del' trias rezultate del' wissenschaft.erforschung des balattonsees, 1/1(1),1-229. kolar-jurkoysek, t. (1991): mikrofavna sred­ njega in zgornjega triasa slovcnijc in njcn biostral i­ gralski pomen.geologija, 33, 21-170, ljubljana. ramoys, a. (1984): nova spoznanja 0 kamijsko norijski meji v vzhodnih julijskih alpah.zborn ik radova anub il-l, 8, 213-218, sarajevo. ramoy§, a. (1985): geoloske raziskave sevem ih julijskih alp in njihov biostratigrafski razvoj.jeklo inljudje, 5, 39 1-428, jcsenice. manuscript received may 24, 1996. revised manuscript accepted april 28, 1997. 4 geologia croatica 50/1 plate i valvasoria camiolica n.gen. n.sp. a) hololype, bj 1286, scale bar 10 mm. b) enlargement of the anterior portion of the holotype, b1 1286, scale bar 5 mm. 2 external surface of the cuticle with pores arranged in rows, paralype, bj 1287, scale bar lo ~m. 3 detail of the external surface of the cuticle showing two pores unequal in size, paratypc, bj 1287, scale bar i011111. 4 cross-section of the cuticle, paratype, bj 1287, scale bar 100 j.lm. kobr-jurkovsck & ju rkovsck plate ! 5 6 gcologi; t croaticil 5011 a middle jurassic radiolarite-clastic succession from the medvednica mt. (nw croatia) josip halami∆ 1, ©pela gori»an 2, damir slovenec 1 and tea kolar-jurkov©ek 3 1. introduction in the last few decades, especially after invention of a method for the extraction of radiolarians from radiolarian cherts (dumitrică, 1970; pessagno & newport, 1972; de wever, 1982), investigation of radiolarian cherts in the mediterranean area has intensified. this is the consequence of their stratigraphic importance, bathymetry of their origin, and their common occurrence with ophiolites. all the aforementioned is extremely important for the palaeogeographic reconstruction of this area. from this perspective, in the geological literature dealing with sw part of the pannonian basin (i.e. nw croatia) deposits of this kind were disregarded, and were only mentioned together with magmatic rocks (gorjanovi∆-kramberger, 1908; babi∆, 1974; ©imuni∆ & ©imuni∆, 1979; ©iki∆ et al., 1979; basch, 1983). the age of the magmatic rocks and associated sedimentary rocks of the northwestern part of the medvednica mt. has been, on the basis of their common appearance together with lower cretaceous clastic carbonate deposits (which usually overlie them), previously determined as either lower cretaceous (©iki∆ et al., 1979; basch, 1983; ©iki∆, 1995), or even upper cretaceous (crnkovi∆, 1963). after the discovery of triassic radiolarites together with basic volcanic rocks from kalnik and medvednica mts. (middle carnian to uppermost carnian norian halami∆ & gori»an, 1995; halami∆, 1998), and triassic limestones (peperites) in pillow lavas from medvednica mt. (upper anisian lower ladinian halami∆ et al., 1998), it has been determined that part of the magmatic rocks with pelagic sediments on the medvednica mt. are of triassic age, without regard to its present geotectonic position (accretionary complex halami∆, 1998). furthermore, during these studies it has been determined that part of siliceous rocks are of jurassic age (halami∆ & gori»an, 1995; halami∆ et al., 1995), and will be discussed in detail in this paper. jurassic radiolarites of the medvednica mt. alternate with shales, siltites, matrix-supported conglomerates, or represent the matrix of olistostromes, and therefore are very important for the palaeogeographic reconstruction of the sw part of the pannonian basin in the jurassic. jurassic mass-flow deposits containing olistoliths of triassic pelagic rocks are known from hungary and g eol. cr oat. 52/1 29 57 17 figs. 4 tabs. 4 pls. zagreb 1999 key words: radiolarite-clastic succession, middle jurassic, radiolarians, conodonts, triassic olistoliths, geochemistry, subduction, accretionary complex, medvednica mt., croatia. 1 institute of geology, sachsova 2, p.o. box 268, hr-10000 zagreb, croatia. 2 ivan rakovec institute of palaentology, zrc sazu, gosposka 13, si-1000 ljubljana, slovenia. 3 geological survey of slovenia, dimiëeva 14, si-1000 ljubljana, slovenia. abstract on the nw part of medvednica mt. radiolarites with carbonate olistoliths, shales and siltites, matrix-supported conglomerates and basic volcanic rocks were investigated. this facies association is informally named the poljanica unit. major element geochemical data indicate deposition of radiolarites in the vicinity of the middle oceanic ridge, while sedimentological data indicate deposition in an area closer to the continent. shales and siltites, as well as matrix-supported conglomerates, were deposited in short periods characterised by increased input of terrigenous material. matrix-supported polymict conglomerates are composed of silicified shales, lithic graywackes, cherts and metabasalts, and were deposited by debris flow mechanisms as a consequence of synsedimentary tectonic activity. carbonate olistoliths are composed of biomicrosparite, and jointly with deformed radiolarian cherts compose an olistostrome. basic volcanic rocks represent high-ti tholeiitic basalts formed in the morb realm. micropalaeontological investigation of radiolarite samples proved the middle jurassic (latest bajocian early bathonian to late bathonian early callovian) age of the poljanica unit. additionally, a new radiolarian species theocapsomma medvednicensis n.sp. has been described. conodont analyses from carbonate olistoliths in radiolarites proved their triassic age. the investigated radiolarite-clastic succession is the result of subduction processes. further continuation of this process caused incorporation of these deposits into the accretionary prism, where they were brought in direct contact with triassic volcanic rocks and radiolarites (in the form of a tectonic mélange). based on the lithological similarities with the middle jurassic turbidite-olistostrome successions in the western carpathians and northern calcareous alps, the study area is considered to be part of the meliata-hallstatt ocean. 30 geologia croatica 52/1 slovakia (kozur, 1984, 1991; kozur & mock, 1985, 1995, 1997; kozur et al., 1996), as well as from austria (mandl & ondreji»ková, 1991, 1993; kozur & mostler, 1992; gawlick, 1993). 3. basic geological data medvednica mt. is situated in the sw part of the pannonian basin, and is incorporated as part of the geodynamic unit supradinaricum (herak, 1986) or inner dinarides (herak et al., 1990). tectonically, the medvednica mt. belongs to the mid-transdanubian zone (sensu haas et al., 1988) or zagorje m i d transdanubian zone (as defined by pami∆ & tomljenovi∆, 1998), which is bounded by the balaton line in the north and the zagreb-zemplen (or midhungarian) line in the south. the core of the medvednica mt. is composed mostly of low-grade metamorphic rocks (various metapelites, metapsammites, slate-phyllite, slates, quartzites, marbles, orthoand paragreenschists of palaeozoic, and partly mesozoic age belak et al., 1995), high-pressure metamorphic rocks (blueschists belak & tiblja©, 1998), magmatic rocks associated with sedimentary rocks (crnkovi∆, 1963; ©iki∆ et al., 1979; halami∆, 1998), and clastic-carbonate deposits of triassic, lower cretaceous and upper cretaceous p a l a e ogene age (©iki∆ et al., 1979; ©iki∆, 1995). this core is surrounded by younger tertiary and quaternary sediments (fig. 1). rocks of the magmatic-sedimentary complex, including those described in this paper, outcrop in the nw part of medvednica mt. over an area of approximately 25 km2. towards the east they are in reverse tectonic contact with low-grade metamorphic rocks, and towards the ne they are bounded from the low-grade metamorphic rocks by the normal fault. along their sw margin rocks of this complex are partly surrounded by lower cretaceous and upper cretaceous p a l a e o g e n e sedimentary rocks, and are partly in contact with lower triassic pelites and psammites and middle and upper triassic limestones and dolomites of the zakiënica nappe (©iki∆, 1995). towards the nw, rocks of the magmatic-sedimentary complex are disconformably overlain by sedimentary rocks of the neogene, which are partly in tectonic contact with them. m a g m a t i c rocks are mainly represented by greenish altered basalts (spilites), with subordinate green-grey massive basalts, pillow lavas, diabases and altered diabases in the form of veins dissecting metabalts, and gabbro and metagabfig. 1 location map and geological sketch map of medvednica mt. (from halami∆ et al., 1998). legend: 1) tertiary sedimentary rocks; 2) cretaceouspalaeogene sedimentary rocks; 3) investigated magmatic and sedimentary rocks; 4) triassic clastic and carbonate rocks of zakiënica nappe; 5) metamorphic rocks; 6) stratigraphic boundary; 7) fault; 8) reverse fault; 9) thrust fault; 10) investigated area. bro. among the sedimentary rocks the most frequent are matrix-supported conglomerates, conglomeratic shales and siltites of brown, grey and dark grey colour, composed of pebbles and blocks of sandstones (lithic greywackes, lithic arenites, sublithoarenites), metabasalts and metagabbros. these sediments are most common above the main magmatic body of the nw medvednica mt., but are also found as decametre-sized packages within basic volcanic rocks (halami∆, 1998). in the sw part of the magmatic-sedimentary complex dark red, grey and green-grey shales, siltites and radiolarian shales are abundant together with dark grey and green-grey radiolarites, which are locally in direct contact to spilites. some radiolarites and pillow lavas with pelagic limestones are of triassic age (halami∆ & gori»an, 1995; halami∆ et al., 1998), and a part of these siliceous and siliciclastic rocks is of jurassic age. 3. petrology 3.1. sedimentary rocks siliceous rocks in the poljanica creek were investigated in detail at three localities, while palaeontological and sedimentary-petrographic studies of outcrops of these rocks south of poljanica and towards the ne to the jelenja voda creek were subsequently performed (fig. 2). the geological column p o l j a n i c a a (figs. 2 & 3a) represents the sequence on the sw bank of the poljanica creek, on both sides of the forest road, approximately 600 m e of poljanica village. the measured deposits are 22.5 m thick. the lower 12 m of the column is composed of grey and green-grey radiolarites characterised by very thin bedding (1-5 cm thick, rarely to 15 cm), which is laterally persistive. bedding surfaces are wavy but sharp. cherts are interbedded with mmto cm-thick beds of silicified shales and clayey silty cherts. the matrix of the radiolarian cherts is composed of cryptocrystalline quartz, while planparallel oriented white mica flakes (?muscovite) averagely 0.01 mm, rarely up to 0.5 mm in size, as well as silt-sized detrital quartz grains are subordinate. an opâque mineral (?fe-hydroxide) found in the form of agglomerates up to 0.6 mm in size is an accessory. these cherts are dissected by mm-thick quartz veins and mutually connected mesh-like stylolites. in the lower part, the rocks are characterised by a weakly expressed, parallel laminated structure, while in the upper part the structure is homogenous. laminae composed of skeletons and relics of radiolarians (up to 0.2 mm in diameter) are less than 2 mm thick. most of the radiolarian skeletons are recrystallized and filled with microcrystalline quartz, while some are filled with radial chalcedony. gradation is not visible, both in the laminated and homogenous types of radiolarian cherts. in the middle part of the column there is a 1.7 m thick bed of dark red and green-red conglomeratic sandy-siltose shale. the deposit is characterised by a slaty structure, and is weathered into cm-sized chips. the rock is matrix-supported, and the matrix is composed of clay minerals and cryptocrystalline quartz, with small subrounded to rounded grains of the same composition, detrital quartz grains (up to 0.1 mm in size) and small rounded grains of quartz siltite. pebbles larger than 2 mm are irregularly distributed, and composed of silty radiolarian cherts and lithic graywacke of a green-grey colour. the overlying interval is 1 m thick, composed of a green-grey massive radiolarite, followed by a 2.6 m thick bed of conglomeratic chert. its lower boundary is sharp and relatively flat, while the upper boundary is sharp, irregular and uneven. deformed grey-reddish 31halamiê, goriëan, slovenec & kolar-jurkovπek: a middle jurassic radiolarite-clastic succession... fig. 2 location map of analyzed samples and sections. 32 geologia croatica 52/1 beds of chert have a slaty structure and contain up to 0.3 m large rounded fragments of light-grey carbonates and reddish cherts. carbonate fragments predominate in the lower part of the bed, and chert fragments in the upper part. carbonates are represented by sporadically silicified biointrasparrudites containing completely recrystallized mollusc debris; these rocks were sampled for conodont analyses (samples pa 16, pa 18 and pa 19 fig. 3). the upper part of the column is composed of a 5.2 m thick succession of grey, homogeneous and laminated radiolarite. the rock is intensely tectonised and disintegrated. laminae show no gradation, similar to those in the lower part of the column. the geological column poljanica-b (figs. 2 and 3b) of the rocks on the sw bank of the poljanica creek, east of the poljanica-a column, in a forest road-cut approximately 900 m e of poljanica village, comprises a 9.6 m thick succession. the lower part of the column is composed of 4.2 m of predominantly radiolarian cherts, with subordinate silty radiolarian cherts of a dark red and reddish colour. the rocks are thin-bedded (5-20 cm). bed surfaces are sharp and wavy. the matrix is composed of cryptocrystalline to microcrystalline quartz, containing radiolarian tests up to 0.15 mm in size, which are partly concentrated in mm-thick laminae and partly distributed irregularly. tests are mostly filled with chalcedony, and infrequently with microcrystalline quartz. accesory minerals are white mica and silt-sized detrital quartz grains. an increased content of quartz, in the form of mm-sized elongated lenses is present in silty radiolarian cherts. rocks are impregnated by fe-hydroxides in the form of pigments, resulting in the dark red and red colour of the entire rocks. lamination is the only structural characteristic represented in the sediment. the middle part of the column is composed of a 0.8 m thick bed composed of lens-shaped fragments (up to 40 cm in diameter) of fine-grained limestones and radiolarian cherts. limestones are represented by biomicrosparites, biomicrites, fossiliferous micrites and microsparites. microsparite matrix, which is partially silicified, in some samples contains 10 -20 % of completely recrystallized 0.1-0.25 mm large grains, probably completely calcitized radiolarian tests. the radiolarian cherts are very similar to those from the lower part of the column. the matrix between carbonate and radiolarian chert fragments is slaty, composed of silicified, dark red shale. the upper part of the column is composed of an alternation of deformed layers of radiolarian cherts and sandy radiolarian cherts. these deposits also contain a fig. 3 geological columns in the poljanica creek (for location see fig. 2). legend: 1) shales; 2) siltites; 3) sandstones; 4) paraconglomerates; 5) cherts; 6) radiolarian cherts; 7) micrites; 8) calcarenites; 9) sedimentarypetrographical analysis; 10) palaeontological analysis; 11) geochemical analysis. 33halamiê, goriëan, slovenec & kolar-jurkovπek: a middle jurassic radiolarite-clastic succession... carbonate olistolith, 1.75 m in size (fig. 4), composed of biocalcarenitic sandstone. the matrix of the radiolarian cherts is composed of microcrystalline quartz with infrequent white mica and quartz grains. the sandy component is composed of quartz grains and mica flakes up to 0.1 mm in size. microand macrofossil detritus, ooid fragments, complete radial ooids and micrite intraclasts, with subordinate quartz, feldspar, microquartzite, microcrystalline quartz and granitoid grains comprise the biocalcarenite. intergranular spaces are filled with drusy calcite cement, which is sporadically silicified. this level could be, according to its sedimentary-petrographic and sedimentological characteristics, correlated to the upper part of the poljanica-a column. the third locality studied is a geological section poljanica-c (figs. 2 and 5), located on the n bank of the poljanica creek, approximately 800 m e of the poljanica village. the lower part of the section is composed of matrixsupported conglomerates. the matrix is comprised of brown-grey, slaty, sandy-silty shale. up to 15 cm sized pebbles are composed of grey and grey-green lithic greywackes. there is no inner organisation of the sediment, which was probably deposited from a mud flow. these conglomerates are followed by a 2 m thick succession of reddish, weakly silty, silicified, radiolarian fig. 4 metre-sized olistolith of light-grey calcarenitic sandstone in dark-red shale (geological column poljanica-b). scale bar = 1 m, sample pb18. fig. 5 geological section poljanica-c (for location see fig. 2). legend: 1) shales; 2) sandstones; 3) cherts; 4) radiolarian cherts; 5) micrites; 6) recrystallized and haematized limestones; 7) pillow lavas; 8) metabasalts; 9) sedimentary-petrographical analysis; 10) palaeontological analysis; 11) chemical analysis; 12) reverse fault. note: pillow lavas with shale intercalations in the lower part of the section could represent an olistolith. 34 geologia croatica 52/1 shales, with sharp and wavy lower bedding surfaces. the sediment is thin-bedded (up to 12 cm), and its matrix is composed of clay minerals and subordinate cryptocrystalline quartz, and impregnated with fehydroxides. a silt-sized component is composed of detrital quartz grains and white mica flakes. the matrix comprises up to 5 % of relatively well-preserved radiolarian tests, up to 0.15 mm in size, which are predominantly filled with a greenish mineral from the chlorite group (?seladonite dragutin slovenec, unpublished). infrequent tests are filled either with a ferruginous-clayey substance or radial chalcedony. these radiolarian shales are covered by a 15 m thick succession of pillow lavas. the contact between the sedimentary and volcanic rocks is sheared, as the result of differing competence of the materials. some pillows are more than 1 m in diameter (fig. 6). these volcanic rocks will be described in more detail later. in the middle and upper part of the effusive succession there are a few decimetre thick beds of sediments in contact with volcanic rocks. these are predominantly haematized and silicified shales. along with the clay minerals, which constitute the rock matrix, there is a silt-sized component composed of quartz grains and planparallely oriented white mica particles, with zircon as an accessory. millimetre-sized veins filled with quartz, plagioclase and calcite dissect the deposit. at the shale/metabasalt boundary “tongues” of the sediment penetrate into the volcanic rock (fig. 7), the contact surface is irregular, and joints in the metabasalt are filled by haematized shale and volcanic fragments. since this outcrop is very restricted, the possibility that the basalt with shale intercalations represents a megablock within the sedimentary succession cannot be excluded. on the basic geological map (©iki∆ et al., 1977) basalts in the poljanica creek are presented as small isolated basalt bodies not exceeding 300 m in diameter. this distribution also suggests that the basalt bodies represent allochthonous blocks in a tectono-sedimentary mélange. after a 15 m thick covered interval the section is continued with matrix-supported conglomerates, which in the lower part are brownish-red, and in the upper part dark red and greenish, partly silicified and partly covered by mn or haematite-limonite crusts. in the lower part the matrix is composed of sandy-silty shale, and pebbles are represented by lithic greywackes and almost completely calcitized cherts. pebbles in the upper part of paraconglomerates are represented by brownish-green metabasalts, greenish lithic greywacke, greenish vitreous and grainy chert and dark red siltite. a further part of the section is composed of very thinand thin-bedded, deformed dark red radiolarian cherts. radiolarian tests in these radiolarites are, as in the lower part of the section, filled by a green, chloritic substance (?seladonite). within the radiolarites irregularly distributed pebbles, cobbles and smaller blocks (olistoliths) of light grey limestones can be found (fig. 8). these carbonates are composed of recrystallized, and sporadically dolomitized biomicrosparites and intrabiomicrosparites. beside the aforementioned columns we have investigated several other localities. at the pijesak locality south of the poljanica creek (sample vh 32 on fig. 2) there is an alternation of centimetre-decimetre thick fig. 7 contact of haematized shale (up) and metabasalt (below). note “tongues” of shale filling fractures in metabasalts (poljanica-c section, below 113/2 sample). fig. 6 outcrop of pillow lavas in the lower part of the poljanica-c geological section. pillows up to 1 m in diameter are well exposed (hammer for scale is 30 cm long). 35halamiê, goriëan, slovenec & kolar-jurkovπek: a middle jurassic radiolarite-clastic succession... beds of reddish radiolarian cherts, greenish cherts and dark red fine-grained quartz arenites. the radiolarian cherts are characterised by the same composition as in the aforementioned successions. the chert is composed of a cryptocrystalline quartz matrix, and 0.03 mm long planparallel oriented sericite particles. detrital, subrounded quartz grains from 0.04-0.22 mm in size, which compose submillimetre-thick laminae, are subordinate, as well as rare radiolarian tests. the chert is characterized by stylolitized bedding surfaces, stylolites being filled by a ferruginous substance. quartz arenites are characterized by a psammitic texture and homogenous structure. they are composed of poorly sorted subrounded detrital grains of quartz, up to 0.5 mm in size, most of them exhibiting undulatory extinction. subordinate muscovite particles up to 0.5 mm in size (longer grains are trapped between quartz grains and fragmented) occur with rock fragments (chert and quartzite) and amphibole. zircon and garnet, as well as opâque minerals are accessory, and a haematite-limonite component fills interstices, causing the reddish colour of the rock. the rock matrix is composed of cryptocrystalline quartz and sericite (fig. 9). at the vh 891 locality (fig. 2) interbedded matrixsupported conglomerates were discovered, which are greenish-grey in colour, and characterized by a slaty structure. a greenish-grey silty shale matrix is composed of clay minerals and cryptocrystalline quartz. subordinate silt-sized, rarely sand-sized detrital quartz grains and white mica also occur. zircon and opâque minerals are accessory. poorly-sorted fragments, 2-50 mm in size are found in the matrix, rarely exhibiting orientation of the longer axis subparallel to the schistosity. the matrix around fragments and pebbles show no signs of their subsequent rotation, indicating that their orientation originated during the flow of the mud mass. fragments are angular to subangular, partly rounded, composed predominantly of dark grey, grey, grey-green and yellow-green silicified shale. some fragments are covered by mn and limonite crusts (fig. 10). at this locality radiolarian chert does not crop out; therefore, these rocks are not dated (see table 1). the vh 967 locality is situated on the slope ne of the poljanica village (fig. 2), and the eastern part of the outcrop is composed of a breccia, which is towards the west followed by grey radiolarites. the breccia matrix is composed of calcarenite consisting predominantly of radial ooids with silicified margins and partly visible agglomeration, as well as fragments of recrystallized fossiliferous micrites, cherts and scarce metabasalts in recrystallized microsparite. centimetre sized fragments in the breccia are predominantly composed of grey and light-grey, partly laminated radiolarian cherts. subordinate fragments include biomicritic limestones and metabasalts. radiolarites found in the western part of the outcrop represent typical ribbon radiolarites composed of chert beds ranging in thickness from a few to ten centimetres. the outcrop at the pe 1 locality is composed exclusively of dark red radiolarite, which is tectonically deformed and folded, and the contact with neighbouring rocks is not visible. fig. 8 decimetre-sized carbonate olistoliths within radiolarian cherts in the upper part of the poljanica-c section (objective cap is 55 mm in diameter). fig. 9 quartz arenite bed within radiolarite (outcrop vh32, sample vh32/4). fig. 10 matrix-supported conglomerate. pebbles are composed of cherts and silicified and manganised shales (outcrop vh891). 36 geologia croatica 52/1 the pd 0 locality is situated in a small abandoned quarry, where an olistolith composed of grey, recrystallized and weakly silicified pelmicrite was found within dark red and grey radiolarites. in the pelmicrite pellets and small circular forms, up to 0.03 mm in diameter, which could represent calcitized radiolarians were found. the pc 50 locality is situated approximately 400 m up-stream of the poljanica-b column (fig. 2). the lower part of the outcrop is composed of grey, fractured radiolarian chert covered by matrix-supported conglomerates. an outcrop of grey to light grey radiolarian cherts at the vh 113 locality (fig. 2) lies toward the e, bounded by a several metre wide tectonic zone of upper cretaceous(?) carbonate-clastic deposits, while towards the w, the outcrops are covered by quaternary deluvial deposits. sample vh 882 (fig. 2) was taken from a several metre-sized outcrop of intensely folded dark red, massive, clayey radiolarian chert. the rock is at places intensely manganized. samples vh 141 and vh 147a (fig. 2) were collected from grey and dark red radiolarian cherts. the associated rocks are radiolarites, polymict and monomict matrix-supported conglomerates and metabasalts in the form of pillow lavas. towards the w these deposits are covered by delluvium, while towards the e they are in tectonic contact with cretaceous calcisiltites and calcarenites. samples vh 558 and jv©p (fig. 2) were taken from grey, greenish and red radiolarites, associated with matrix-supported conglomerates and metadiabase and metabasalt blocks. rocks from these localities represent part of the poljanica lithostratigraphic unit, which is composed of radiolarites, siltites and shales with limestone olistoliths, ?blocks of basic volcanic rocks and matrix-supported conglomerates. the footwall of this unit is not defined, while the hanging-wall is composed of debrites of the markov travnik unit, which are in disconformable contact with the poljanica unit. deposits of these units are allochthonous to neighbouring rocks, and represent parts of the accretionary complex (halami∆, 1998). 3.2. volcanic rocks in the eastern part of the poljanica-c section (fig. 5) basic volcanic rocks are present in the form of pillow lavas. these rocks are green (in the lower part) to red (upper part), characterised by irregular fracturing. there are several textural varieties of metabasalts. metabasalt texture is predominantly microcrystalline, ophitic and porphyric-ophitic, and in the upper part of the section towards the contact with shale also divergent-radial. the structure in the lower part is amygdaloidal, while towards the upper part it becomes massive. vesicles are monomineralic, composed either of calcite, chlorite or fine-grained quartz (up to 0.7 mm in diameter). on the basis of textural and structural characteristics the following varieties of metabasalts were separated: ophitic, porphyric-ophitic and divergentradial. these varieties contain the mineral association of albite ± altered clinopyroxene ± secondary minerals. albite in the groundmass has a twig-like habit, commonly ranging 0.1-0.9 mm in size, and rarely occurs in the form of phenocrysts up to 1.6 mm in length. grains are mostly inhomogenous because of small inclusions of chlorite, calcite and minerals from the zoisite-epidote group. albite originated from the alteration of basic plagioclases, by the albitization process under the hydrothermal influence during the postmagmatic phase. clinopyroxenes were found exclusively in the upper part of this sequence as small skeletal relics of yellow augite. in other parts of the succession, albite interstices are filled with completely weathered contours or aggregates of former pyroxenes, which were postmagmatically hydrothermally altered into an aggregate of chlorite and blurred cryptocrystalline mass of ?clinozoisiteepidote. interstices in the upper part of the sequence, near the contact with shale, contain finely dispersed haematite, and on the surface (weathering crust) also limonite, and sporadically radial prehnite, formed by alteration of basic plagioclases. besides chlorite, which is the most abundant alteration product, there is secondary, finegrained calcite which substitute other constituents of the rock, forming irregular aggregates or filling numerous veins. opâque minerals, finely dispersed magnetite and skeletal ilmenite are accessory. besides the poljanica-c section, basic volcanic rocks in the contact with red shales and cherts were investigated at two other localities. locality vs 94 is situated in the poljanica creek valley, 350 m e of poljanica village, and locality vh 1001/1 is located on the ne bank of the nameless creek, in the area called popovëica, approximately 500 m south of oreπje village (fig. 2). these rocks are green, and according to their microphysiographic properties they are identical to the aforementioned rocks from the poljanica-c section. due to their ophitic texture and massive structure they were determined as ophitic metabasalts. main rock-forming minerals, especially pyroxenes, are completely altered, predominantly into chlorite and calcite. associated sedimentary rocks from these localities were not dated. 4. stratigraphy 4.1. radiolarian dating twenty samples of red and green chert were examined for radiolarians. they were prepared using standard hf methods. the location of all samples is shown on the map (fig. 2), the stratigraphic position of the samples from the poljanica-c (samples 113a), poljani37halamiê, goriëan, slovenec & kolar-jurkovπek: a middle jurassic radiolarite-clastic succession... ca-a (samples pa), and poljanica-b (samples pb) sections is shown in figs. 3 and 5. small nassellarians predominate in all samples, spumellarians are represented by rare bernoullius and emi l u v i a in addition to some indeterminable fragments (spines, rays). planktonic foraminifera were found in sample pd 0. the radiolarian dating (table 1) is based on the zonation of baumgartner et al. (1995b). eight samples correspond to the uaz 5 and two to the uaz 7. the assemblages in the other samples do not contain species or pairs of species characteristic of one zone and allow only a broader age assignment corresponding mainly to uazs 5 to 7. the minimum range of the poljanica unit is thus latest bajocian early bathonian (uaz 5) to late bathonian early callovian (uaz 7). theocapsomma cucurbiformis was found in the sample vh 882/1, which is assigned to the uaz 5 based on the co-occurrence of guexella nudata and t h e o capsomma cordis with unuma latusicostatus . this association suggests that the range of t. cucurbiformis (uaz 6 to 7) should be extended. t. cucurbiformis i s therefore not considered indicative of uaz 6 and uaz 7 in the other samples. another example is xitus mag nus, supposed to make its first appearance in the uaz 8 but already occurring in the uaz 7 (see sample vh 967) in association with dictyomitrella ? k a m o e n s i s, stichocapsa naradaniensis and tricolocapsa conexa . the shortened ranges of t. cucurbiformis and x. mag nus in the zonation of baumgartner et al. (1995b) are due to a small number of records for these two species in their database. tricolocapsa plicarum s.l. ranges from uaz 3 to uaz 8 while both subspecies t. plicarum plicarum and t. plicarum ssp. a, range only from uaz 4 to uaz 5. this discrepancy exists because in the oldest and youngest samples containing t. plicarum, this species was not introduced at subspecific level in the database of baumgartner et al. (1995b). the proposed ranges of t. plicarum plicarum and t. plicarum ssp. a are therefore not considered reliable and were not used for age determination. the sample pa 15 comes from a deformed, brecciated chert bed. in addition to c y r t o c a p s a a f f . m a s toidea, stichocapsa robusta a n d tricolocapsa tetrago n a , which first appear in the uaz 5, it also contains cyrtocapsa mastoidea , which is restricted to uazs 3 and 4 and seems to be reworked. the uaz 5 or younger age of this sample is also evidenced by its stratigraphic position above the uaz 5 (sample pa12). 4.1.1. systematics of radiolarians basic synonymy is provided for the species which are not included in the catalogue of baumgartner et al. (1995a). theocapsomma medvednicensis n.sp. is introduced; a short description is given for the species in open nomenclature. we retained the generic names (see species list in table 1) commonly used in the literature on jurassic radiolarians, although some of these names are not in agreement with iczn rules. two examples of incorrect generic assignment have recently been discussed by kozur et al. (1996). most of these taxonomic problems are not satisfactorily solved yet and would need a more thorough revision, which is beyond the scope of this paper. canoptum sp. a (pl. iii, figs. 18-22) 1985 c a n o p t u m sp. yamamoto et al., p. 34, pl. 3, fig. 10. d e s c r i p t i o n : test multicyrtid, conical, with well pronounced constrictions. surface rough, covered with small irregularly arranged nodes. minute pores present on circumferential ridges. a thin spongy meshwork is developed on some specimens (pl. iii, fig. 18) suggesting that c a n o p t u m is closely related to s p o n g o c a p s u l a pessagno. the pitted surface of the circumferential ridges on some specimens resembles that of cinguloturris carpatica d u m i t r ică. it seems that s p o n g o c a p s u l a and c i n g u l o t u r r i s evolved from canoptum. cyrtocapsa aff. mastoidea yao (pl. i, fig. 24) 1994 cyrtocapsa a f f . mastoidea yao gori»an, p. 65, pl. 9, fig. 20. 1995a stichocapsa sp. e baumgartner et al., p. 524, pl. 4042. obesacapsula magniglobosa aita (pl. iii, figs. 6, 7 a-b) 1987 obesacapsula magniglobosa n. sp. aita, p. 71, pl. 2, figs. 4a-b; pl. 9, figs. 10-11. parvicingula ? cappa cortese (pl. iii, figs. 8-9) 1993 parvicingula cappa n. sp. cortese, p. 176, pl. 4, figs. 1-4. protunuma fusiformis ichikawa & yao (pl. ii, figs. 14-16) 1976 protunuma fusiformis n. sp. ichikawa & yao, p. 116, pl. 2, figs. 1-4. protunuma ? lanosus oævoldová (pl. ii, figs. 20-22) 1996 ?protunuma lanosus oævoldová n. sp. sykora & oævoldová, p. 23, pl. 2, fig. 13; pl. 3, figs. 1-6. genus: theocapsomma haeckel, emend. foreman theocapsomma medvednicensis gori»an n. sp. (pl. i, figs. 12a-b, 13, 14a-b, 15-16) 1997 t h e o c a p s o m m a sp. a arakawa, pl. 6, fig. 17. 38 geologia croatica 52/1 .. .... " .... .. " .... • .. .. '" ii .. .. .. .. .. .. .. .. .. '" ii ~ [0 .... .. .. .. ... " 1': 8 .. ii .. ... ..x " ii .. ~ .. ic:llcmx .. " .. x .. x x .. .. .. .. .. .. .. ....... .. .. .. .. -~ .. -0( :.::it .iii: _ _ 39halamiê, goriëan, slovenec & kolar-jurkovπek: a middle jurassic radiolarite-clastic succession... holotype: pl. i, fig. 12a-b; sample pa 12. etymology: the species is named after its type locality, medvednica mountain, northern croatia. d e s c r i p t i o n : test composed of three segments. cephalis small, hemispherical. thorax and abdomen much larger, hemispherical; abdomen distally constricted, having a circular aperture. the lumbar stricture well marked. thorax and abdomen bear small circular pores. thorax and lumbar stricture covered with vertical ridges, the distal part of the abdomen is nodose. r e m a r k s : theocapsomma medvednicensis n.sp. differs from t. cordis kocher (kocher, 1981, p. 100, pl. 17, figs. 2-4) by having ridges on the thorax and at the lumbar stricture. it differs from t. cucurbifor m i s baumgartner (baumgartner et al., 1995a, p. 574, pl. 3047) and t. bicornis b a u mgartner (baumgartner et al., 1995a, p. 572, pl. 3276) by having no horn. measurements (in µm, based on 13 specimens): total height holotype: 90, minimum: 75, maximum: 115, average: 91; width of thorax holotype: 50, minimum: 45, maximum: 60, average: 52; width of abdomen: holotype: 63, minimum: 55, maximum: 75, average: 64. tricolocapsa sp. a sensu yamamoto et al. (pl. ii, figs. 5-6) 1985 tricolocapsa sp. a yamamoto et al., p. 39, pl. 8, figs. 6a-c. 1991 striatojaponocapsa sp. kozur, pl. 3, fig. 3. 1997 protunuma (?) sp. a arakawa, pl. 5, fig. 7. tricolocapsa sp. a (pl. ii, figs. 10-12) 1993 tricolocapsa sp. maaté et al., fig. 3/14, 15. d e s c r i p t i o n : test composed of three segments. cephalis and thorax small, partly encased in the abdomen. abdomen subspherical, inflated. thorax and abdomen perforate, and covered by longitudinal plicae. on the thorax, the plicae are connected with transverse ridges. several rows of small circular pores present between adjacent plicae and transverse ridges. unuma darnoensis kozur (pl. ii, fig. 13) 1991 unuma darnoensis n.sp. kozur, pl. 2, fig. 2. 1994 unuma darnoensis kozur gori»an, p. 95, pl. 10, figs. 7-8, 9a-b. williriedellum marcucciae cortese (pl. i, figs. 26-28) 1993 williriedellum ( ? )marcuccii n.sp. cortese, p. 180, pl. 7, figs. 6-7. 1995a w i l l i r i e d e l l u m sp. a sensu matsuoka baumgartner et al., p. 628, pl. 4060, and synonymy therein. xitus sp. a. (pl. iii, figs. 1-4) 1993 xitus (?) sp. a cortese, p. 181, pl. 7, fig. 8. 1997 x i t u s sp. matsuoka & baumgartner, pl. 3, fig. 16. description: test short, conical. cephalis smooth, poreless, bearing a stout apical horn. thorax and the following segments with pores. prominent tubercles are developed on the post-thoracic segments. 4.2. conodont dating 4.2.1. material and methods seven samples between 0.5 to 1.5 kg were collected and processed for conodonts by dissolving them in 15% acetic acid following standard conodont techniques. after laboratory treatment only four samples proved to contain conodont elements. the frequency of conodonts is low, mostly of fragmentary preservation. the fossil material is stored at the geological survey of slovenia, catalogue numbers iggg 3139-3141. the figured conodont specimens were photographed on an em geol by dr. k. dra©lar (institute of biology, university of ljubljana). the location of investigated samples is shown in figs. 2 and 3. 4.2.2. conodont fauna sample pa 16a (iggg 3128) the sample yields a microfauna that includes foraminifera (toplypammina discoidea t r i f o n o v a ) , ostracods (polycope sp.), echinoderm ossicles as well as conodont elements norigondolella steinbergensis (mosher) (pl. iv, fig. 2) and epigondolella ex gr. postera (kozur & mostler) (pl. iv, fig. 1). age: middle upper norian. in slovenia, diagnostic norian elements epigondolella postera and n o r i gondolella steinbergensis have been recognized in the p o s t e r a -a.z. (alaunian) and b i d e n t a t a-r.z. (sevatian) (kolar-jurkov©ek, 1991). r e m a r k s : the elements which are characterized by a narrow platform, about half of the total unit length and denticles arranged on the anterior part of the plattable 1 occurrence of radiolarian species in the samples studied. the first column gives zonal ranges of species according to baumgartner et al. (1995b), the age of the samples is shown in the bottom row. the radiolarian dating indicates that the poljanica unit spans at least from the latest bajocian -early bathonian (uaz 5) to the late bathonian early callovian (uaz 7). note that the sample pa 15 contains a mixed radiolarian assemblage. 40 geologia croatica 52/1 form are here assigned to e p i g o n d o l e l l a ex gr. p o s t e r a (kozur & mostler). similar elements were separated from the e. postera population of canada (orchard, 1983) and described as e. elongata o r c h ard where it is a name-bearer of the middle norian elongata zone (orchard, 1991b). sample pa 18 (iggg 3130) the sample produced a small microfauna including ramiform conodont elements and rare but diagnostic platform conodont elements of paragondolella foliata budurov. age: the species is characteristic of upper langoba r d i an uppermost julian (kovács, 1983) and has been reported from the tethyan realm except for the west mediterranean province (kozur, 1973; kovács, 1983). sample pa 19a (iggg 3131) the microfauna contains numerous ramiform and platform conodont elements, however mainly of fragmentary preservation. the elements of neocavitella s p . and paragondolella tadpole (hayashi) (pl. iv, fig. 3) are recognized. a g e : stratigraphic range of paragondolella tadpole (hayashi) is the cordevolian lower tuvalian interval (kovács & kozur, 1980; kovács, 1983). sample pb 18 (iggg 3134) a small microfauna is represented by rare foraminifera and a single conodont element referred to norigon dolella navicula (huckriede). age: stratigraphic range of norigondolella navicula is confined to the norian stage (kovács & kozur, 1980; kozur, 1990) and it is regarded as definitive of the basal norian (orchard, 1991a). 4.2.3. summary of the conodont dating triassic conodont faunas are recorded from mt. medvednica, croatia. element p. foliata is recognized in the sample pa 18. it is an index species of the f o l i a t a -r.z. that in slovenia encompasses upper langobardian and lower cordevolian (kolar-jurkov©ek, 1991). the sample pa 19a is characterized by the carnian species p. tadpole . the presence of the ladinian-carnian and carnian conodont elements has been hitherto proved in several locations of mt. medvednica (–ur–anovi∆, 1973; belak et al., 1995). norian conodonts were collected in two outcrops. the element n. navicula was recovered from the sample pb 18 thus proving a norian age. a diverse fauna of the sample pa 16a contains e. ex gr. postera and n. stein b e r g e n s i s . in slovenia, e. postera is recorded in the middle and upper norian (kolar-jurkov©ek, 1991). 5. geochemistry 5.1. radiolarites geochemical analyses were undertaken on the radiolarian cherts from the radiolarite succession, which were dated as jurassic on the basis of radiolarians. additionally, shale samples were collected for correlational purposes. the position of samples in columns and sections, as well as in the field, is presented in figs. 2, 3 and 5. major elements in sedimentary rocks were determined by standard wet chemical analyses. the ca, f e2o3, mg and al contents were analysed complexometrically by edta with corresponding indicators; ti, mn and p were analysed spectrophotometrically from the same solution. the k and na contents were determined by flame photometry, while the fe2+ and si contents were determined gravimetrically. volatiles were measured by loss of ignition at 1150 °c. trace elements were done by the icp-aes method at acme analytical laboratories ltd. (vancouver). rock samples were milled into powder and homogenized in an agate mill. a sample of 0.25 gr. was digested with 10 ml hclo4-h n o3-h clhf at 200 °c to fuming and diluted to 10 ml with diluted aqua regia. this leach is partial for magnetite, chromite, barite, oxides of al, zr and mn and massive sulphide samples. recalculated contents of major elements on 100 % without volatiles, trace elements contents, as well as various ratios between majorand trace elements are presented in table 2. in addition, the table contains average values of majorand trace element contents of the triassic radiolarian cherts and shales (halami∆ & gori»an, 1995; halami∆, 1998). chemical elements can be divided into three groups according to their origin in siliceous deposits. the first group comprise biogenic silica, originating from siliceous tests, spicules and other skeletal detritus. the second group is of terrigenous origin, comprising elements which are predominately related to clay minerals: sio2, t i o2, al2o3, feo*, mgo, na2o, k2o, cr, rb and zr. the third group of so-called hydrogenous elements ( f e2o3, mno, cu, ni, v and zn) comprise elements which are predominantly precipitated directly from marine water (matsumoto & ijima, 1983). alternation of radiolarian cherts and shale beds in radiolarites results from the mutual influence of several processes. it has been undoubtedly proven that during diagenesis there is a segregation of silica from siliceous mud into nodules, lenses and beds (tada, 1991; murray et al., 1992a, b, c; de wever, 1994; murray, 1994 and cited literature). however, beside diagenetic processes, during the deposition of mud there is an alternation of periods characterised by increased bioproductivity (e.g. radiolarians) with the constant sedimentation rate of clastic detritus, or increased input of clastic detritus with constant bioproduction (decker, 1991; de wever, 1994). furthermore, 41halamiê, goriëan, slovenec & kolar-jurkovπek: a middle jurassic radiolarite-clastic succession... partial redeposition of sedimented material by contour currents or low-density turbidite currents is indicated by the sedimentary structures preserved in radiolarian cherts, like gradation, horizontal and wavy lamination and load casts on lower bedding surfaces (nisbet & price, 1974; folk & mcbride, 1978; vecsei et al., 1989; halami∆ & gori»an, 1995). investigations of recent and ancient oceanic siliceous deposits have shown, that during diagenesis, fractionation and migration of some elements occur, which partly result in the formation of radiolarian chert/shale alternation. during these processes important mobilization of biogenic sio2 takes place, which migrates into beds enriched in silica, and from these beds mn, ca, radiolarian cherts siliceous silty shales vh pa1 pa5 pa20 pb2 vh x sd x* vh vs vs 113/3 pa pb x sd x* 558/4 882 n=5 558/2 941) 103/11) 14c 01) n=5 sio2 89.37 91.70 88.42 91.45 95.40 91.00 91.22 2.41 91.27 78.38 70.11 62.72 64.27 79.09 87.15 73.62 9.53 79.97 tio2 0.21 0.20 0.24 0.28 0.12 0.24 0.22 0.05 0.18 0.44 0.61 0.73 0.30 1.44 0.22 0.62 0.44 0.42 al 2o3 0.40 1.80 2.57 2.90 1.55 0.94 1.69 0.95 2.93 9.22 12.38 13.27 5.69 3.96 5.47 8.33 3.89 7.03 fe2o3 6.40 4.13 6.86 3.03 2.03 4.98 4.57 1.89 2.87 5.97 7.09 9.71 10.67 6.42 3.31 7.20 2.67 5.33 mno 0.36 0.05 0.13 0.10 0.05 0.05 0.12 0.12 0.13 0.03 0.12 0.09 0.37 0.20 0.15 0.16 0.12 0.12 mgo 1.07 0.59 0.49 0.59 0.28 0.37 0.57 0.28 0.78 0.92 1.45 1.73 16.33 0.62 0.57 3.60 6.25 1.58 cao 1.72 0.32 0.69 0.37 0.20 0.23 0.59 0.58 0.79 0.73 1.41 0.93 1.87 2.81 0.97 1.45 0.78 1.68 na2o 0.13 0.15 0.15 0.12 0.08 1.23 0.31 0.45 0.35 0.45 1.25 5.41 0.98 0.86 0.31 1.54 1.93 0.87 k2o 0.68 1.21 0.70 1.29 0.41 1.19 0.91 0.36 0.80 4.05 5.68 5.53 1.20 4.87 1.94 3.88 1.89 3.10 p2o5 0.02 0.01 0.01 0.02 0.01 0.01 0.01 0.01 0.00 0.01 0.01 0.02 0.00 0.02 0.01 0.01 0.01 0.01 caco3 2.92 0.46 1.06 0.49 0.27 0.34 0.92 1.02 1.23 0.77 1.77 0.92 2.81 4.50 1.41 2.03 1.41 2.50 al 2o3 / tio2 1.91 9.00 10.71 10.36 12.92 3.92 8.14 4.28 16.28 20.95 20.30 18.18 18.97 2.75 24.86 17.67 7.67 16.74 fe2o3 / tio2 30.48 20.65 28.58 10.82 16.92 20.75 21.37 7.31 15.94 13.57 11.62 13.30 35.57 4.46 15.05 15.60 10.47 12.69 100x fe2o3 /sio2 7.16 4.50 7.76 3.31 2.13 5.47 5.06 2.18 3.14 7.62 10.11 15.48 16.60 8.12 3.80 10.29 4.91 6.66 100x al 2o3 / sio2 0.45 1.96 2.91 3.17 1.62 1.03 1.86 1.05 3.21 11.76 17.66 21.16 8.85 5.01 6.28 11.79 6.44 8.79 fe2o3 / 100-sio2 0.60 0.50 0.59 0.35 0.44 0.55 0.51 0.09 0.33 0.28 0.24 0.26 0.30 0.31 0.26 0.28 0.03 0.27 al 2o3 / 100-sio2 0.04 0.22 0.22 0.34 0.34 0.10 0.21 0.12 0.34 0.43 0.41 0.36 0.16 0.19 0.43 0.33 0.12 0.35 al 2o3 / al 2o3+fe2o3 0.06 0.30 0.27 0.49 0.43 0.16 0.29 0.16 0.51 0.61 0.64 0.58 0.35 0.38 0.62 0.53 0.13 0.57 si / si+al+ fe+ca 0.88 0.91 0.86 0.92 0.95 0.91 0.91 0.03 0.91 0.79 0.72 0.67 0.72 0.81 0.87 0.76 0.07 0.81 al / al+ fe+mn 0.04 0.25 0.22 0.41 0.36 0.12 0.23 0.14 0.43 0.54 0.56 0.51 0.28 0.31 0.54 0.46 0.13 0.47 ba 51 104 98 92 71 85 84 20 130 206 239 276 35 229 100 181 93 297 th 2 2 3 3 < 2 3 2 1 2 7 9 11 5 10 3 8 3 7 nb 2 5 4 4 2 2 3 1 3 6 8 7 3 10 4 6 3 7 sr 37 35 37 58 14 25 34 15 24 49 49 60 16 38 32 41 16 45 y 9 6 6 10 2 6 7 3 4 10 14 25 11 18 12 15 6 10 zr 7 23 21 22 6 15 16 8 13 21 39 58 23 53 20 36 17 38 sc 4 5 6 7 2 6 5 2 4 13 19 23 7 17 7 14 7 12 cr 15 18 25 26 9 20 19 6 16 60 73 97 42 85 30 65 26 37 ni 48 23 26 32 10 44 31 14 20 45 56 116 200 86 32 89 62 54 cu 35 41 55 59 25 47 44 13 51 20 68 81 9 113 65 59 39 88 pb 27 <5 < 5 7 < 5 6 9 9 7 11 20 29 < 5 < 5 7 13 10 15 zn 67 32 44 20 11 55 38 21 33 52 48 118 46 117 33 69 38 72 co 25 7 6 23 5 26 15 10 8 13 7 31 21 28 12 19 10 15 v 25 31 34 45 15 35 31 10 21 93 115 159 107 142 47 111 39 50 la 6 9 13 13 3 10 9 4 7 23 30 36 11 31 13 24 10 18 th/sc 0.50 0.40 0.50 0.43 0.50 0.50 0.47 0.04 0.50 0.54 0.47 0.48 0.71 0.59 0.43 0.54 0.10 0.58 table 2 major element content (%), recalculated on 100% without volatiles and some trace elements (mg/kg) in radiolarian cherts and radiolarian shales. major element analysis were performed by classical silicate-chemical method at the institute of geology, zagreb; analyst: vlasta juri©i∆-mitrovi∆. trace elements were measured by icp-aes at acme laboratories, vancouver, canada. legend: x) average value; sd) standard deviation; x*) average values of triassic sediments (after halami∆ & gori»an, 1995). 1) shale samples are not dated because of the lack of fossil material; however, they are attributed to the poljanica unit since they contact dated cherts. 42 geologia croatica 52/1 mg, p, sr and ba are remobilized and removed (murray, 1994). manganese is especially subject to these processes, and its migration is further enhanced during subductional-accretional processes involving pelagic sediments. during diagenesis moderately migrative elements entering into chert beds are k, na, ge, co and b, while v migrates out. on the basis of these facts murray (1994) proposed that only al, ti, fe and rare earth elements should be used as the most reliable for determination of the geotectonic position of radiolarites and radiolarian chert origin with discrimination diagrams (girty et al., 1996). as a result of the important migration of sio2 d u ring the diagenetic processes, radiolarian tests within shale beds should be weakly preserved (murray et al., 1992a). however, microscopic examination of thinsections prepared from samples of silicified shale beds of jurassic radiolarites of medvednica mt. and similar rocks of triassic age from kalnik and medvednica mts., has shown that radiolarian tests in these rocks are best preserved (halami∆ & gori»an, 1995; halami∆, 1998). therefore, for estimation of the biogenic silica contents in radiolarites we used a value of the si / si+ al+fe+ca ratio (rangin et al., 1981; ruitz-ortiz et al., 1989), while for calculation of caco3 we used a method after baltuck (1982). examination of the major element contents in the analysed samples (table 2) revealed that some of the shale samples are characterised by significantly increased sio2 contents, and therefore could be determined as siliceous shales. furthermore, shales have much higher values of all major elements than the cherts (except sio2, feo and mno contents), which is the result of the quantity and variability of terrigenous material composing the shales. the fe content of shales is generally significantly higher than that of the cherts. results of trace element analysis of shales show generally higher values of all trace elements in respect to cherts, which is caused by the higher clay minerals content of shales. the si / si+al+fe+ca ratio presents information on the content of biogenic silica with respect to aluminosilicates and ferrugenous and calcic minerals (rangin et al., 1981; ruitz-ortiz et al., 1989). rocks rich in biogenic silica have ratio values between 0.8 0.9. investigated radiolarian cherts have an average ratio value on the upper boundary of this range (0.9 see table 2), indicating that the major part of silica in cherts originates from siliceous tests and biogenic siliceous detritus. the principal portion of silica in shales is also of biogenic origin (high values of the ratio 0.76), which is further indicated by well preserved radiolarian skeletons in shales. calculated values of the fe2o3/tio2, al2o3/(al2o3+ fe2o3), 100xfe2o3/sio2, 100xal2o3/sio2, fe2o3/100sio2 and al2o3/ 100-sio2 ratios (table 2) were inserted into discrimination diagrams after murray (1994). this author suggested the aforementioned major element ratios as the most reliable for the determination of depositional environments for siliceous rocks. his chemical sedimentary model distinguished three areas on these diagrams: a) spreading ridge proximal or near ridge, b) pelagic (including parts of the sedimentary area closer to the continent, but topographically protected from more important terrigenous input) and c) contifig. 11 a) diagram of fe2o3 /a l2o3 ratio normalized on sio2. points representing analyzed samples bundle in the field indicating vicinity of the mid-oceanic ridge; b) diagram representing f e2o3 /a l2o3 ratio normalized on 100 -s i o2. the analyzed samples also bundle in the field indicating vicinity of the mid-oceanic ridge; c) diagram showing bundling of jurassic radiolarite samples near the field indicating vicinity of the mid-oceanic ridge, but are below it because of the increased ti values. to a lesser extent samples fall within the field of pelagic environment. *) average value for triassic cherts (n=5; after halami∆ & gori»an, 1995). 43halamiê, goriëan, slovenec & kolar-jurkovπek: a middle jurassic radiolarite-clastic succession... nental margin (back-arc basins, marginal seas, epicontinental seas and open continental shelves) (murray, 1994, p. 218). on the basis of calculation of the aforementioned major element ratios, investigated jurassic radiolarites fall within the fields of the area near the mid-oceanic ridge (fig. 11a and b). figure 11c shows a certain dissipation of a minor part of the data into the pelagic area, while the major part is grouped in the area which corresponds to the vicinity of the mid-oceanic ridge. since they are connected with aluminosilicates, al and ti are good indicators of a terrigenous influence. the al2o3/t i o2 ratio for the analysed cherts ranges from 1.91-12.92 (average value 8.14 see table 2), indicating that detrital material in cherts may have originated from an undifferentiated magmatic arc characterised by a predominance of basic magmatic rocks over acid varieties (al2o3/ t i o2 ratio values for these areas are ≤14 girty et al., 1996). however, the possibility of a detrital origin from the accretionary prism comprising parts of the morb cannot be excluded. values of the th/sc ratio for jurassic cherts (table 2) also indicates an origin of the material from a magmatic arc, but also a possible origin from oceanic island arcs. despite the fact that manganese is very mobile during diagenetic and later processes (as previously discussed), we took values of the al/al+fe+ mn ratio for evaluation of the hydrothermal influence on the origin of the siliceous sediments (baltuck, 1982; adachi et al., 1986), i.e. for estimation of the contribution of continental material in respect to the oceanic material (ruitz-ortiz at al., 1989). removal of manganese from this calculation would not significantly change values of this ratio (because of its small contents in the rocks from 0.05-0.36%, average 0.12%), while in this case it would not be possible to compare our results with published data. the value of this ratio for typical continental material is 0.619 (average value for shale), for marine biogenic material 0.391, for basaltic material of the eastern pacific rift 0.00815 (baltuck, 1982), and for pelagic clays 0.54 (wedepohl, 1969). the studied jurassic cherts exhibit much lower average values (0.23) than for continental material, which indicate a large distance from the continental mass to the sedimentary area, i.e. weaker terrigenous influence. in contrast, debris flow beds and siltite and shales indicate a more important input of terrigenous material. increased values of al /al+fe+mn ratio in shales in respect to cherts represent a consequence of the higher contents of clay minerals. 5.2. volcanic rocks geochemical analysis were performed on 4 samples of magmatic rocks (figs. 2 and 5). samples vs113/1 and vs113a4 were collected on the poljanica-c geological section (fig. 5). samples vs94 and vh1001 from separate localities (fig. 2) are taken from rocks which are in contact with dark red haematized shales without any fossil remains, and therefore they were not stratigraphically determined; however, on the basis of geological relationships they are attributed to the poljanica unit. major element and some trace element (rb, sr, y, nb and ba) analyses were performed by the xrf method at xral laboratories (canada). other trace elements were analysed by the icp-aes method in acme analytical laboratories (canada). results of these analyses are presented in table 3, and the cipw normative composition and petrochemical indices in table 4. sample vh vs vs vs vh vs vs vs average 1001 94 113/1 113a4 10011) 941) 113/11) 113a41) *morb sio2 46.90 37.00 48.10 44.30 51.01 42.08 52.25 49.25 49.10 ± 1.50 tio2 2.13 1.44 0.93 1.11 2.31 1.64 1.03 1.23 1.17 ±0.05 al 2o3 13.10 16.60 14.00 15.40 14.25 18.88 15.50 17.12 15.60 ± 1.60 fe2o3 3.63 2.94 2.43 2.61 3.95 3.34 2.69 2.90 2.60 ± 1.40 feo 9.51 9.77 2.95 6.27 10.34 11.11 3.27 6.97 6.70 ± 1.70 mno 0.29 1.60 0.29 0.83 0.32 1.82 0.32 0.92 0.16 ±0.03 mgo 7.90 9.39 5.68 11.10 8.59 10.68 6.29 12.34 8.20 ±2.30 cao 5.06 5.81 12.00 4.67 5.50 6.61 13.28 5.19 11.80 ± 1.40 na2o 3.03 3.06 3.55 3.47 3.29 3.49 3.93 3.86 2.40 ± 0.50 k2o 0.17 0.03 0.26 0.06 0.18 0.03 0.29 0.06 0.20 ±0.19 p2o5 0.23 0.29 0.14 0.12 0.25 0.33 0.15 0.13 0.12 ± 0.05 loi 6.35 11.20 8.20 9.50 total 99.40 100.30 99.00 100.30 ba 213 298 189 124 cr <50 312 364 780 nb 8 18 12 8 sr 116 52 169 73 v 458 168 238 213 y 51 34 24 25 zr 151 106 75 81 table 3 chemical composition of metabasalts (wt. %) and some trace elements (mg/kg). 1) recalculated on 100 % without volatiles. *morb) middle-oceanic ridge basalt (wedepohl, 1988). 44 geologia croatica 52/1 according to their sio2 contents on the tas diagram (le bas et al., 1986) samples vh1001 and vs113a4 represent basic rocks, sample vs94 ultrabasic, while sample vs113/1 falls within the field of neutral rocks, but very close to the border with basic rocks (fig. 12). on the same diagram two analyzed samples fell within the basalt field, and sample vs113/1 in the field of basaltic andesite, as a consequence of increased s i o2 contents resulting from the presence of quartz vesicles. sample vs94, which represents the most altered rock, falls within the field of basanite and tephrite because of the low sio2 contents, which is a consequence of the presence of a large quantity of chlorite, pumpellyite(?), and less prehnite, the formation of which caused migration of the surplus silica from the rock. according to the normative cipw composition (table 4), most of the samples contain normative hypersthene, except sample vs94 which contains normative nepheline and belong to the alkali basalts. furthermore, normative olivine is present in most samples, and is especially high in sample vs94, where it is stated instead of chlorite. high values of normative nepheline and olivine in sample vs94 are caused by high na contents, which is introduced in the rock by hydrothermal solutions with insufficient si. in normative anorcipw norms petrochemical indices sample vh vs vs vs vh vs vs vs 1001 94 113/1 113a4 1001 94 113/1 113a4 qz 2.01 ai 5.3 1.0 6.8 1.7 c 1.89 1.58 fi 38.7 34.7 24.1 43.0 or 1.09 0.20 1.70 0.39 mi 62.5 57.5 48.7 44.4 ab 27.88 21.48 33.25 32.64 si 33.1 37.7 38.8 47.7 an 23.53 30.63 23.80 24.89 di 31.0 26.0 34.9 33.0 ne 4.32 vsm th th ca ca diwo 0.89 17.16 vsib b pb b b dien 0.53 13.12 difs 0.31 2.24 ca calc-alk. hyen 20.86 1.20 11.55 th tholeiite hyfs 12.18 0.21 3.79 b basalt olfo 18.64 0.94 13.45 pb picrite basalt olfa 14.15 0.18 4.86 mt 5.72 4.58 3.90 4.21 hm il 4.40 3.11 1.95 2.34 ap 0.58 0.76 0.36 0.31 norm pl. (%an) 46 52 42 43 table 4 cipw normative composition and petrochemical indices. fig. 12 tas diagram (le bas et al., 1986). legend: 1) basanite and tephrite; ii) phonotephrite; iii) tephriphonolite; iv) basaltic trachyandesite; v) trachybasalts; vi) basalts; vii) basaltic andesite; viii) andesite. fig. 13 tio2 vs. zr /p2o5 diagram (winchester & floyd, 1976). 45halamiê, goriëan, slovenec & kolar-jurkovπek: a middle jurassic radiolarite-clastic succession... thite part of the calcium from the zoisite-epidote group, as well as prehnite and rarely augite is included; these minerals are very common, and therefore increase the anorthite contents. by comparison of some major elements contents with the average major element contents in oceanic tholeiites of mid-oceanic ridges (morb; table 3) increased na2o contents (as a consequence of postconsolidational changes) and decreased k2o contents may be noted. in sample vh1001 tio2 is increased, in sample vs94 mno is increased, while in sample vs113/1 the fe2 + content is significantly decreased. contents of other major elements are within the range of average values for morb. on the tio2 vs. zr /p2o5 diagram (winchester & floyd, 1976) all samples fall within the field of tholeiite, except sample vs-94 which belongs to the alkali basalts (fig. 13). on the basis of sio2 v s . ( n a2o + k2o) ratio (miyashiro, 1974) it is visible that samples vh1001 and vs113/1 fall within the field of subalkalic basalts, and samples vs94 and vs113a4 within the field of alkali basalts (fig. 14). however, on the sio2 vs. feo*/ mgo diagram (miyashiro, 1974) samples vs113/1 and vs113a4 fall within the field of calc-alkali basalts, sample vh1001 in the field of the tholeiitic series, and sample vs94 in the same field, although outside the diagram (because of decreased sio2 contents). contents of some typical trace elements were used for the interpretation of geotectonic regime in which basic magmas were produced. on the ti-v diagram (shervais, 1982) all rocks belong to high-titanium basalts formed in the morb realm (ti /v ratio > 2 0 ) , except sample vs94, which, due to decreased value of v, falls outside the area (fig. 15). a similar situation is present on the zr :t i / 1 00 :yx3 diagram (pearce & cann, 1973), where all analyzed rocks are concentrated within the morb field (fig. 16). on the zr/4:2 nb: y diagram (meschede, 1986) analyzed samples mostly fall within the e-morb type field, except for one sample which falls within the n-morb field (fig. 17). due to the small number of samples, processes of hydrothermal alteration, spilitization and low-grade metamorphism, together with the enhanced mobility of some major elements, the analyzed rocks concerning the magma character show two different results: they belong to alkalic, but also to tholeiitic rock series. fresh rocks belong to the tholeiitic series, which suggests their primary tholeiitic character. in the geotectonic sense analyzed metabasalts belong to the tholeiitic basalts of the mor. 6. discussion radiolarian cherts in radiolarites show no sedimentary structures except lamination. a lack of other structures indicates the “normal” deposition, i.e. alternation of periods with increased bioproduction or periods with fig. 15 ti-v discrimination diagram (shervais, 1982). legend: i) arc tholeiite; ii) calc-alkali basalts; iii) morb and bab; iv) continental flood basalts; v) ocean-island and alkali basalts. fig. 14 variation diagram f e o* /mgo vs. sio2 and tas diagram (miyashiro, 1974). 46 geologia croatica 52/1 increased input of terrigenous material. the difference in silica contents in different layers is further increased by diagenetic processes (tada, 1991; murray et al., 1992a; murray, 1994). centimetre-thick layers of quartz arenite within radiolarite are the consequence of rapid deposition by gravity flows, while the angularity of grains indicates relatively short transport. on the basis of mineral composition (predominantly undulatory quartz, microquartzite, garnet and mica, and only subordinate magmatogenic quartz) it may be concluded that the continental source area was composed mostly of metamorphic rocks, and subordinately of acid magmatic rocks. metre-thick layers of matrix-supported conglomerates within the radiolarites described from the vh891 locality (fig. 2), as well as from other localities, are the consequence of tectonic activity within the depositional area or on its margin, which resulted in debris flows of unconsolidated sediments. in the study area radiolarites s. str. are subordinate to shales and siltites, and are found as metre-decametre thick packages within pelitic sediments. this indicates that: a) periods with increased input of terrigenous material were much longer than those with increased bioproductivity, or b) that significantly increased input of terrigenous material took place in a short period. debris flow layers support the latter assumption. geochemically analyzed radiolarite samples fall within the diagrammatic fields suggesting the vicinity of the ridge (fig. 11a-c). this might be related to some sediment input from the oceanic crust or accretionary wedge as also suggested by metabasalt clasts in conglomerates. on the basis of the appearance of decimetre-metre sized carbonate olistoliths of triassic age in radiolarites, it may be concluded that parts of the triassic carbonate platform were, during the middle jurassic, located close to the sedimentary realm where siliceous rocks were deposited. carbonate rocks formed the relatively steep slopes of the sedimentary basin, and their parts disintegrated and fell into unconsolidated siliceous mud. additionally, these tectonically uplifted parts represented a barrier to a greater input of terrigenous material into the sedimentary basin. this described arrangement of elevated areas and a deeper-water sedimentary basin is a consequence of subduction processes which were already active in this area (halami∆, 1998). further subduction caused more severe disintegration of the described deposits and resulted in formation of a tectonic mélange, which also incorporated parts of the triassic oceanic crust (basic magmatic rocks) as well as parts of the triassic siliceous rocks. similar middle jurassic successions composed of chert, shale, sandstone and olistostromes with clasts of triassic rocks were described from the western carpathians (kozur & mock, 1985, 1995, 1997; kozur, 1991; kozur et al., 1996) and from the northern calcareous alps (mandl & ondreji»ková, 1991, 1993; kozur & mostler, 1992). these facies associations are considered the most characteristic lower mesozoic tectofacies of the meliaticum (kozur & mock, 1997). halami∆ & gori»an (1995) correlated the triassic radiolarites overlying basic volcanic rocks in the study area, with those of the meliata unit. the presence of a middle jurassic (uppermost bajofig. 16 zr: t i / 1 00 : yx3 diagram (pearce & cann, 1973). legend: a) island-arc tholeiites; b) morb; c) calc-alkali basalts; d) within-plate basalts. fig. 17 zr/4 :2 nb :y diagram (meschede, 1986). legend: ai) within-plate alkali basalts; aii) within-plate alkali basalts and within-plate tholeiite; b) e-type morb; c) within-plate tholeiite and volcanic-arc basalts; d) n-type morb and volcanic-arc basalts. 47halamiê, goriëan, slovenec & kolar-jurkovπek: a middle jurassic radiolarite-clastic succession... c i an lower bathonian to upper bathonian lower callovian) radiolarite-clastic succession further supports the idea that the study area was part of the meliatahallstatt ocean. halami∆ & gori»an (1995) pointed out that the triassic basalts are younger in the medv e d n i ca kalnik area (middle carnian to uppermost c a r n i an norian than in the meliata unit (ladinian to lower carnian). more recently, halami∆ et al. (1998) proved that some pillow lavas of morb type in medvednica mt. are as old as upper anisian to lower ladinian. the age difference between the basalts in the meliata unit and the medvednica-kalnik area is thus minor and does not contradict the assignment of the studied mesozoic succession to the meliata-hallstatt ocean. halami∆ & gori»an (1995) correlated the m e d v e d n i ca kalnik area also with the vardar zone in serbia, based on the occurrence of carnian n o r i a n basic volcanics in both areas. the ophiolite-bearing clastic succession (ophiolitic mélange) of the vardar zone is assignable to the middle and upper jurassic as evidenced by its stratigraphic position (dimitrijevi∆, 1995). due to the lack of more precise biostratigraphic data for the jurassic successions of the vardar zone, a reliable correlation with the poljanica unit is still not possible. 7. conclusions siliceous and siliciclastic deposits from the area between the poljanica and jelenja voda creeks in nw medvednica mt. consist of radiolarites s. str., shales and siltites, radiolarian cherts with carbonate olistoliths and matrix-supported conglomerates. these rocks were attributed to the poljanica informal lithostratigraphic unit. on the basis of radiolarians it is concluded that the analyzed radiolarites were deposited from the latest b a j o c i an early bathonian (uaz 5) to late bathonian early callovian (uaz 7). furthermore, study of conodonts from the carbonate olistoliths proved their late ladinian carnian, carnian and norian age. geochemical scatter diagrams of major elements indicate that the radiolarites were deposited in the area close to the mid-oceanic ridge. however, sedimentological characteristics indicate significant input of terrigenous detritus (matrix-supported conglomerates, siltites and shales), which suggests proximity to the continent. for comparison, diagrams include data for triassic cherts from the same area (halami∆ & gori»an, 1995), which were, according to geochemical data, also deposited in marginal areas, i.e. in the area closer to the continental mass. several textural varieties of metabasalts associated with siliceous rocks were analyzed petrographically. geochemical analysis of these rocks indicated that these high-titanium tholeiitic basalts were generated in the area of the mid-oceanic ridge. it should be noted that the age of these metabasalts has not been proven. it is possible that they represent large olistoliths or offscraped blocks in the mélange and could thus be middle to late triassic in age. investigated middle jurassic radiolarites with triassic carbonate olistoliths, shales and siltites, matrix-supported conglomerates and basic volcanic rocks were incorporated in an accretionary prism, where they were brought in direct contact with triassic volcanic rocks and radiolarites (tectonic mélange). based on the lithological similarities with middle jurassic turbidite olistostrome successions in the western carpathians and in the northern calcareous alps, the study area is considered to have been part of the meliata hallstatt ocean. this palaeogeographic location is also suggested by previously documented triassic basic volcanics (halami∆ & gori»an, 1995; halami∆ et al., 1998). acknowledgements the authors are grateful to drs. h. kozur (budapest), l. dosztály (budapest), s. kovács (budapest), l. palinka© (zagreb) and i. veli∆ (zagreb) for their critical reading and improvement of the manuscript. the authors are indebted to dr. m.j. orchard (vancouver) for critical reading of the conodont dating section. we wish to thank i. lapajne (ljubljana) and m. grm (ljubljana) for processing the scanning electron micrographs of radiolarians. 8. references adachi, m., yamamoto, k. & sugisaki, r. (1986): hydrothermal chert and associated siliceous rocks from the northern pacific: their geological significance as indication of ocean ridge activity.sed. geol., 47, 125-148. aita, y. (1987): middle jurassic to lower cretaceous radiolarian biostratigraphy of shikoku with reference to selected sections in lombardy basin and sicily.tohoku univ., sci. rep., 2nd ser. (geol.), 58/1, 1-91. arakawa, r. (1997): jurassic radiolarian succesion from the siliceous mudstone in the kuzuu area of the ashio terrane, central japan. part i.bull. tochigi pref. mus., 14, 1-19. babi∆, lj. (1974): jurassic-cretaceous sequence of mt. ivanπëica (northern croatia).bull. sci. cons. acad. yougosl., (a)19/7-8, 180-181, zagreb. baltuck, m. (1982): provenance and distribution of tethyan pelagic and hemipelagic siliceous sediments, pindos mountains, greece.sedim. geol., 31, 63-88. basch, o. (1983): osnovna geoloπka karta sfrj 1:100 000. tumaë za list ivaniê grad l33-81.inst. 48 geologia croatica 52/1 za geol. istr. zagreb (1980), savez. geol. zavod, beograd, 66 p. baumgartner, p.o., o’dogherty, l., gori»an, ©., dumitrică-jud, r., dumitrică, p., pillevuit, a., urquhart, e., matsuoka, a. & danelian, t. (1995a): radiolarian catalogue and systematics of middle jurassic to early cretaceous tethyan genera and species.in: baumgartner, p.o., o’dogherty, l., gori»an, ©., urquhart, e., pillevuit, a. & de wever, p. (eds): middle jurassic to lower cretaceous radiolaria of tethys: occurrences, systematics, biochronology. mémoires de géologie, 23, 37-688, lausanne. baumgartner, p.o., bartolini, a., carter, e.s., conti, m., cortese, g., danelian, t., de wever, p., dumitrică-jud, r., gori»an, ©., guex, j., hull, d.m., kito, n., marcucci, m., matsuoka, a., murchey, b., o’dogherty, l., savary, j., vishnevskaya, v., widz, d. & yao, a. (1995b): middle jurassic to early cretaceous radiolarian biochronology of tethys based on unitary association.in: baumgartner, p.o., o’dogherty, l., gori»an, ©., urquhart, e., pillevuit, a. & de wever, p. (eds.): middle jurassic to lower cretaceous radiolaria of tethys: occurrences, systematics, biochronology. mémoires de géologie, 23, 1013-1038, lausanne. belak, m. & tiblja©, d. (1998): discovery of blueschists in the medvednica mountain (northern croatia) and their significance for the interpretation of the geotectonic evolution of the area.geol. croatica, 51/1, 27-32. belak, m., pami∆, j., kolar-jurkov©ek, t., peckay, z. & karan, d. (1995): alpinski regionalmetamorfni kompleks medvednice (sjeverozapadna hrvatska).1st croatian geological congress, proceedings, 1, 67-70, zagreb. cortese, g. (1993): radiolarian biostratigraphy of the tuscan cherts (tuscan succession) from val di lima, tuscany, northern apennines.paleopelagos, 3, 165-185. crnkovi∆, b. (1963): petrografija i petrogeneza magmatita sjeverne strane medvednice.geol. vjesnik, 16, 63-160. decker, k. (1991): rhythmic bedding in siliceous sediments an overview.in: einsele, g., ricken, w. & seilacher, a. (eds.): cycles and events in stratigraphy. springer verlag, 464-479, heidelberg, new york. de wever, p. (1982): radiolaires du trias et du lias de la tethys (systematique, stratigraphie).société géologique du nord, 7, 599 p., lille. de wever, p. (1994): radiolarians and radiolarites.c. r. acad. sci. paris, ii, 513-526. dimitrijevi∆, m.d. (1995): geologija jugoslavije (geology of yugoslavia) (in serbian).geoinstitut, barex, 205 p., beograd. d u m i t r i că, p. (1970): cryptocephalic and cryptothoracic nassellaria in some mesozoic deposits in romania.rev. roum. geol. geophys. geogr., ser. geol., 14/1, 45-124. –ur–anovi∆, æ. (1973): o paleozoiku i trijasu medvednice (zagrebaëke gore) i podruëja dvora na uni na temelju konodonti (about paleozoic and triassic of mt. medvednica and the dvor (una) area based on conodonts).geol. vjesnik, 25, 29-49. folk, r.l. & mcbride, e.f. (1978): radiolarites and their relation to subjacent “oceanic crust” in liguria, italy.jour. sed. petrol., 48, 4, 1069-1102. gawlick, h.-j. (1993): triassische tiefwasserfazieskomponenten (kieselkalke, radiolarite) in der jurassischen strubbergbrekzie am tennengebirgsnordrand (nördliche kalkaalpen, österreich).jb. geol. b.-a., 136/2, 347-350. girty, g.h., ridge, d.l., knaack, c., johnson, d. & al-riyami, r.k. (1996): provenance and depositional setting of paleozoic chert and argillite, sierra nevada, california.jour. sed. research, 66/1, 107-118. gori»an, ©. (1994): jurassic and cretaceous radiolarian biostratigraphy and sedimentary evolution of the budva zone (dinarides, montenegro).mémoires de géologie, 18, 1-177, lausanne. gorjanovi∆ kramberger, d. (1908): geologijska prijegledna karta i tumaë geologijskoj karti zagreb (zona 22, col. xiv).naklada kr. zemaljske vlade, 1-75, zagreb. haas, j., rálisch-felgenhauer, e., oravecz-scheffer, a., nagy, e. & bérczi-makk, a. (1988): triassic key sections in the midtransdanubian (igal) structural zone.acta geol. hungarica, 31/1-2, 3-17. halami∆, j. (1998): litostratigrafska karakterizacija jurskih i krednih sedimenata s ofiolitima medvednice, kalnika i ivanπëice.unpublished phd thesis, university of zagreb, 188 p. halami∆, j. & gori»an, ©. (1995): triassic radiolarites from mts. kalnik and medvednica (northwestern croatia).geol. croatica, 48/2, 129-146. halami∆, j., gori»an, ©. & slovenec, d. (1995): pelagiëki silicijski sedimenti sjeverozapadnog dijela medvednice).1st croatian geological congress, abstracts, 36, zagreb. halami∆, j., slovenec, d. & kolar-jurkov©ek, t. (1998): triassic pelagic limestones in pillow lavas in the oreπje quarry near gornja bistra, medvednica mt. (northwest croatia).geol. croatica, 51/1, 33-45. 49halamiê, goriëan, slovenec & kolar-jurkovπek: a middle jurassic radiolarite-clastic succession... herak, m. (1986): a new concept of geotectonics of the dinarides.acta geol., 16/1, 1-42, zagreb. herak, m., jami»i∆, d., ©imuni∆, a. & bukovac, j. (1990): the northern boundary of the dinarides.acta geol., 20/1, 5-27, zagreb. ichikawa, k. & yao, a. (1976): two new genera of mesozoic cyrtoid radiolarians from japan.in: takayanagi, y. & saito, t. (eds.): progress in micropaleontology. micropaleontology press, 110-117. kocher, r.n. (1981): biostratigraphische untersuchungen oberjurassischer radiolarienführender gesteine, insbesondere der südalpen.mitt. aus dem geol. inst. der eidgenossischen techn. hochschule und der univ. zürich, neue folge, 234, 1-184. kolar-jurkov©ek, t. (1991): mikrofavna srednjega in zgornjega triasa slovenije in njen biostratigrafski pomen.geologija, 33 (1990), 21-170, ljubljana. kovács, s. (1983): on the evolution of excelsa-stock in the upper ladinian-carnian (conodonta, genus g o n d o l e l l a, triassic).schrift. erdwiss. komm., 5, 107-120, wien. kovács, h. & kozur, s. (1980): stratigraphische reichweite der wichtigsten conodonten (ohne zahnreihenconodonten) der mittelund obertrias.geol. paläont. mitt. innsbruck, 10/2, 47-78. kozur, h. (1973): beiträge zur stratigraphie und paläontologie der trias.geol. paläont. mitt. innsbruck, 3/1, 1-30. kozur, h. (1984): new biostratigraphical data from the bükk, uppony and mecsek mountains and their tectonic implications.acta geol. hungarica, 27/34, 307-319. kozur, h. (1990): n o r i g o n d o l e l l a n. gen., eine neue obertriassische conodontengattung.paläont. z., 64/1-2, 125-132. kozur, h. (1991): the evolution of the meliata-hallstatt ocean and its significance for the early evolution of the eastern alps and western carpathians.palaeogeography, palaeoclimatology, palaeoecology, 87, 109-135. kozur, h. & mock, r. (1985): erster nachweis von jura in der meliata-einheit der südlichen westkarpaten.geol. paläont. mitt. innsbruck, 13, 10, 223-238. kozur, h. & mock, r. (1995): first evidence of jurassic in the folkmar suture zone of the meliaticum in slovakia and its tectonic implications.mineralia slovaka, 27, 301-307. kozur, h. & mock, r. (1997): new paleogeographic and tectonic interpretations in the slovakian carpathians and their implications for correlations with eastern alps and other parts of the western tethys. part ii: inner western carpathians.mineralia slovaka, 29, 164-209. kozur, h.w., mock, r. & oævoldová, l. (1996): new biostratigraphic results in the meliaticum in its type area around meliata village (slovakia) and their tectonic and paleogeographic significance.geol. paläont. mitt. innsbruck, 21, 89121. kozur, h. & mostler, h. (1992): erster paläontologischer nachweis von meliaticum and süd-rudabányaicum in den nördlichen kalkalpen (österreich) und ihre beziehungen zu den abfolgen in den westkarpaten.geol. paläont. mitt. innsbruck, 18, 87-129. le bas, m.j., le maitre, r.w., streckeisen a. & zanettin, b. (1986): a chemical classification of volcanic rocks based on the total alkali silica diagram.jour. petrol., 27/3, 745-750. maaté, a., martin-algarra, a., o’dogherty, l., sandoval, j. & baumgartner, p.o. (1993): découverte du dogger dans la dorsale calcaire interne au sud de tétouan (rif septentrional, maroc). conséquences paléogéographiques.c. r. acad. sci. paris, 317, ser. ii, 227-233. mandl, g.w. & ondreji»ková, a. (1991): über eine triadische tiefwasserfazies (radiolarite, tonschiefer) in den nördlichen kalkalpen ein vorbericht.jb. geol. b.-a., 134/2, 309-318. mandl, g.w. & ondreji»ková, a. (1993): radiolarien und conodonten aus dem meliatikum im ostabschnitt der nördlichen kalkalpen (österreich).jb., geol., b.-a., 136/4, 841-871. matsumoto, r. & iijima, a. (1983): chemical sedimentology of some bedded cherts in japan.in: iijima, a., hein, j.r. & siever, r. (eds.): siliceous deposits in the pacific region. elsevier, 175192, amsterdam. matsuoka, a. & baumgartner, p.o. (1997): middle jurassic radiolarians from the basal sediments at dsdp site 534, blake bahama basin, northern atlantic.news of osaka micropaleontologists, spec. vol., 10, 183-191. meschede, m. (1986): a method of discriminating between different types of mid ocean ridge basalts and continental tholeiites with the nb-zr-y diagram.chemical geology, 56, 207-218. miyashiro, a. (1974): volcanic rock series in island arcs and active continental margins.amer. journ. sciences, 274, 321-355. murray, r.w. (1994): chemical criteria to identify the depositional environment of chert: general principles and applications.sedimentary geol., 90, 213-232. 50 geologia croatica 52/1 murray, r.w., jones, d.l. & buchholtz ten brink, m.r. (1992a): diagenetic formation of bedded chert: evidence from chemistry of chertshale couplet.geology, 20, 271-274. murray, r.w., buchholtz ten brink, m.r., gerlach, d.c., price, r. iii g. & jones, d.l. (1992b): rare earth, major, and trace element composition of monterey and dsdp chert and associated host sediment: assessing the influence of chemical fractionation during diagenesis.geochim. et cosmochim. acta, 56, 2657-2671. murray, r.w., buchholtz ten brink, m.r., gerlach, d.c., price, r. iii g. & jones, d.l. (1992c): interoceanic variation in the rare earth, major, and trace element depositional chemistry of chert: perspectives gained from the dsdp and odp record.geochim. et cosmochim. acta, 56, 18971913. nisbet, e.g. & price, i. (1974): siliceous turbidites: bedded cherts as redeposited, ocean ridge-derived sediments.spec. publs. int. ass. sediment., 1, 351366. orchard, m.j. (1983): e p i g o n d o l e l l a p o p u l a t i o n s and their phylogeny and zonation in the upper triassic.fossils and strata, 15, 177-192, oslo. orchard, m.j. (1991a): late triassic conodont biochronology and biostratigraphy of the kunga group, queen charlotte islands, british columbia.geol. survey of canada, paper 90-10, 173-193, vancouver. plate i radiolarians for each illustration the sample number, sem-negative number, and magnification are indicated. the scanning electron micrographs were taken on a jeol jsm-330a at the institute of palaeontology, scientific research centre of the slovenian academy of sciences and arts. rock samples, residues and sem negatives are stored in the collection of the second author. 1-2 eucyrtidiellum ptyctum(riedel & sanfilippo), 1: vh 558/5, 961022; 2: vh 967, 971905; 200x. 3 eucyrtidiellum nodosum wakita, vh 967, 971906, 200x. 4 eucyrtidiellum unumaense pustulatum baumgartner, 113 a13, 962111, 200x. 5 bernoullius cristatus baumgartner, jv©p, 971006, 200x. 6-7 guexella nudata (kocher), 6: pa 12, 960716; 7: jv©p, 971026; 200x. 8-9 stylocapsa oblongula kocher, 8: pe 1, 960113; 9: vh 967, 971934; 200x. 10-11 theocapsomma cucurbiformis baumgartner, 10: pa 15, 961603; 11: vh 882/1, 961733; 200x. 12-16 theocapsomma medvednicensis gori»an n. sp., 12 (holotype): pa 12, a: 960718, b: antapical view, 980101; 13: pb 18a, 960332; 14: pb 18a, a: 960326, b: antapical view, 980115; 15: pa 12, 960527; 16: pd 0, 961101; 300x. 17-19 theocapsomma cordis kocher, 17: jv©p, 971005; 18: vh882/1, 961735; 19: vh 967, 971914; 300x. 20 stichocapsa himedaruma aita, pd 0, 961035, 300x. 21 tricolocapsa? fusiformis yao, pa 15, 961614, 300x. 22 tricolocapsa? aff. fusiformis yao, pd 0, 961207, 300x. 23 cyrtocapsa mastoidea yao, pa 15, 961534, 200x. 24 cyrtocapsa aff. mastoidea yao, pa 15, 961535, 200x. 25a, b stichocapsa robusta matsuoka, pb 18a, 25a: 960321; 25b: antapical view, 960320; 200x. 26-28 williriedellum marcucciae cortese, 26: vh 882/1, 961722; 27: pa 12, 960611; 28: pa 12, 960609; 200x. 51halamiê, goriëan, slovenec & kolar-jurkovπek plate i 52 geologia croatica 52/1 orchard, m.j. (1991b): upper triassic conodont biochronology and new index species from the canadian cordillera.geol. survey of canada bull., 417, 299-335, vancouver. pami∆, j. & tomljenovi∆, b. (1998): basic geological data from the croatian part of the zagorje mid-transdanubian zone.acta geol. hungarica, 41/4, 389-400, budapest. pearce, j.a. & cann, j.r (1973): tectonic setting of basic volcanic rocks determined using trace element analyses.earth planet. sci. lett. 19, 290-300. pessagno, e.a. & newport, r.l. (1972): a technique for extracting radiolaria from radiolarian cherts.micropaleontology, 18/2, 231-234. rangin, c., steinberg, m. & bonnot-courtois, c. (1981): geochemistry of the mesozoic bedded chert of central baja california (vizcainocedros-san benito): implications for paleogeographic reconstruction of an old oceanic basin.earth planet. sci. lett., 54, 313-322. ruitz-ortiz, p.a., bustillo, m.a. & molina, j.m. (1989): radiolarite sequences of the subbetic, betic cordillera, southern spain.in: hein, j.r. & obradovi∆, j. (eds.): siliceous deposits of the tethys and pacific regions. springer verlag, 107127, new york, berlin, heidelberg, london, paris, tokyo. shervais, j.w. (1982): ti-v plots and the petrogenesis of modern and ophiolitic lavas.earth. planet. sci. lett., 59, 101-118. sykora, m. & oævoldová, l. (1996): lithoclasts of middle jurassic radiolarites in debris flow sediments from silica nappe (locality bleskovy pramen, slovak karst, western carpathians).mineralia slovaka, 28, 21-25. ©iki∆, k. (1995): prikaz geoloπke grae medvednice.in: ©iki∆, k. (ed.): geoloπki vodië medvednice. plate ii radiolarians for each illustration the sample number, sem-negative number, and magnification are indicated. the scanning electron micrographs were taken on a jeol jsm-330a at the institute of palaeontology, scientific research centre of the slovenian academy of sciences and arts. rock samples, residues and sem negatives are stored in the collection of the second author. 1 tricolocapsa plicarum plicarum yao, pa 15, 961608, 200x. 2 a, b tricolocapsa plicarum ssp. a sensu baumgartner et al., pd 0, 2a: 961116; 2b: antapical view, 961115; 200x. 3-4 tricolocapsa conexa matsuoka, 3: pa 12, 960510, 4: pb 18a, 960317; 200x. 5-6 tricolocapsa sp. a sensu yamamoto et al., 5: pa 12, 960532; 6: vh 882/1, 961727; 300x. 7-8 tricolocapsa tetragona matsuoka, 7: pd 0, 961129; 8: pb 18a, 960310; 200x. 9 stichocapsa naradaniensis matsuoka, vh 967, 971912, 300x. 10-12 tricolocapsa sp. a, pa 12; 10: 960518; 11: 960713; 12: 960520; 200x. 13 unuma darnoensis kozur, 113 a3, 961913, 200x. 14-16 protunuma fusiformis ichikawa & yao, 14: vh 967, 971908; 15: pa 15, 961612; 16: pa 15, 961613; 200x. 17-18 unuma latusicostatus (aita), 17: pa 12, 960524; 18: pd 0, 961219; 200x. 19 protunuma turbo matsuoka, pb 7, 961504, 200x. 20-22 protunuma? lanosus oævoldová, 20: pd 0, 961208; 21: pa 12, 960515; 22: pb 6, 961409; 300x. 23-24 protunuma? ochiensis matsuoka, pa 12, 23: 960615; 24: 960721; 200x. 25-27 archaeodictyomitra? amabilis aita, 25: pd 0, 961114; 26: pd 0, 961212; 27: pa 12, 960604; 200x. 53halamiê, goriëan, slovenec & kolar-jurkovπek plate ii 54 geologia croatica 52/1 inst. za geol. istraæ. and ina-naftaplin, 7-30, zagreb. ©iki∆, k., basch, o. & ©imuni∆, an. (1977): osnovna geoloπka karta 1:100.000. list zagreb l3880.inst. za geol. istraæ. zagreb (1972), sav. geol. zavod, beograd. ©iki∆, k., basch, o. & ©imuni∆, an. (1979): osnovna geoloπka karta sfrj 1:100 000. tumaë za list zagreb l33-80.inst. za geol. istr. zagreb (1972), sav. geol. zavod, beograd, 81 p. ©imuni∆, al. & ©imuni∆, an. (1979): litofacijelno raπëlanjivanje mezozojskih naslaga kalniëkog gorja.zbornik radova 4. god. znan. skupa sekcije za primjenu geol., geofiz., geokem. znan. savjeta za naftu jugosl. akad. znan. i umjet., stubiëke toplice (1978), 125-137, zagreb. tada, r. (1991): compaction and cementation in siliceous rock and their possible effect on bedding enhancement.in: einsele, g., ricken, w. & seilacher, a. (eds.): cycles and events in stratigraphy. springer verlag, 480-491, heidelberg, new york. vecsei, a., frisch, w., pirzer, m. & wetzel, a. (1989): origin and tectonic significance of radiolarian chert in the austroalpine rifted continental margin.in: hein, j.r. & obradovi∆, j. (eds.): siliceous deposits of the tethys and pacific regions. springer verlag, 65-80, new york, berlin, heidelberg, london, paris, tokyo. wedepohl, k.h. (1969): composition and abundance of common sedimentary rocks.in: wedepohl, k.h. (ed.): handbook of geochemistry, vol. i. springer verlag, 250-271, berlin, heidelberg, new york. wedepohl, k.h. (1988): spilitization in the ocean crust and seawater balances.fortschr. miner., 66/2, 129-146. plate iii radiolarians for each illustration the sample number, sem-negative number, and magnification are indicated. the scanning electron micrographs were taken on a jeol jsm-330a at the institute of palaeontology, scientific research centre of the slovenian academy of sciences and arts. rock samples, residues and sem negatives are stored in the collection of the second author. 1-4 xitus sp. a, 1: pd 0, 961125; 2: pd 0, 961102; 3: pc 50, 962228; 4: vh 147a, 960229; 200x. 5 xitus magnus baumgartner, vh 967, 971928, 150x. 6-7a, b obesacapsula magniglobosa aita, 6: pb 18a, 960413; 7: pd 0, a: 961033; b: antapical view, 961034; 200x. 8-9 parvicingula ? cappa cortese, 8: 113 a13, 962030; 9: pb 18a, 960334; 300x. 10-11 parvicingula dhimenaensis baumgartner s.l., 10: pa 12, 960635; 11: pa 12, 960631; 200x. 12 ristola procera (pessagno), vh 967, 971921, 200x. 13-16 d i c t y o m i t r e l l a? k a m o e n s i s mizutani & kido, 13: pa 12, 960621; 14: pa 18a, 960427; 15: pa 18a, 960428; 16: pd 0, 961209; 200x. 17 ristola? turpicula pessagno & whalen, pa 12, 960720, 200x. 18-22 canoptum sp. a, 18: pb 18a, 960403; 19: pb 18a, 960410; 20: pa 12, 960727; 21: pd 0, 961221; 22: pb 18a, 960415; 200x. 23-24 stichomitra? takanoensis aita gr., 23: pb 7, 961503; 24: pa 12, 960728; 200x. 25-26 cinguloturris carpatica dumitrică, 25: vh 967, 971923; 26: vh 967, 971926; 200x. 27 transhsuum brevicostatum (oævoldová) gr., vh 141, 962233, 200x. 55halamiê, goriëan, slovenec & kolar-jurkovπek plate iii 56 geologia croatica 52/1 plate iv conodonts scale bar = 100 µm. 1 e p i g o n d o l e l l a ex gr. postera (kozur & mostler), sample pa 16a (iggg 3128), 1a: oblique oral view, 1b: aboral view. 2 norigondolella steinbergensis (mosher), sample pa 16a (iggg 3128), 2a: oral view, 2b: lateral view, 2c: aboral view. 3 paragondolella tadpole (hayashi), sample pa 19a (iggg 3131), 3a: oblique oral view, 3b: lateral view, 3c: aboral view (anteriormost platform broken off). winchester, j.a. & floyd, p.a. (1976): geochemical magma type discrimination: aplication to altered and metamorphosed basic igneous rocks.earth planet. sci. lett., 28, 459-469. yamamoto, h., mizutani, s. & kagami, h. (1985): middle jurassic radiolarians from blake bahama basin, west atlantic ocean.bull. nagoya univer. museum, 1, 25-49. manuscript received may 18, 1998. revised manuscript accepted may 28, 1999. 57halamiê, goriëan, slovenec & kolar-jurkovπek plate iv 58 geologia croatica 52/1 vrsaljko et al..indd stratigraphy and palaeogeography of miocene deposits from the marginal area of žumberak mt. and the samoborsko gorje mts. (northwestern croatia) davor vrsaljko1, davor pavelić2 and zlatan bajraktarević3 1. introduction investigated area is located approximately 10–50 km sw of zagreb, comprising the miocene surface terrains of the southeastern slopes of žumberak mt. and the northeastern slopes of the samoborsko gorje mts. (figs. 1 and 2). these terrains are the main objects of interest, covering about 150 km2, starting from ozalj, krašić and st. jana in the south, along the southeastern slopes of plešivica mt., across to svetonedeljski breg, and the region surrounding samobor (figs. 1 and 2). for comparison with neighbouring areas, the closest miocene deposits of the draganići structure and the southwestern part of medvednica mt. were used, along with those in the karlovac–2 deep exploratory well (figs. 1, 2 and 5). from a palaeogeographic point of view, the study area belongs to the marginal area of the southwestern part of the pannonian basin (and the south-western part of central paratethys – fig. 1). this position conditioned the specific evolution of the depositional area during the miocene. miocene sediments are most commonly in tectonic contact with mesozoic carbonates while less often with palaeogene rocks which constitute a major part of the core of žumberak mt. and the samoborsko gorje mts. (šikić & basch, 1975; šikić et al., 1978). towards the northeast, this area borders the sava depression (figs. 1 and 2). there are different types of relationships between the miocene basins of the žumberak mt. and samoborsko gorje mts. with other sedimentation areas, such as the karlovac depression, western part of the sava depression, and the basins of hrvatsko zagorje. during the miocene, along the marginal faults (of nw–se strike) and some younger transverse strike-slip faults (of nw–se strike) “positive and negative structures” were formed that led to the observed lateral and vertical distribution of the depositional environments (šikić & basch, 1975). synsedimentary tectonic movements conditioned the migration of depositional environments and facies, which is most pronounced in the frequent lateral and vertical changes of miocene clastic and carbonate series (similar to concept of magyar et al., 1999; figs. 4 and 5). geologia croatica 58/2 133–150 11 figs. zagreb 2005 key words: stratigraphy, palaeogeography, miocene, žumberak mt., samoborsko gorje mts., northwestern croatia, central paratethys, pannonian basin, croatia. 1 croatian geological survey, p.o. box 268, hr-10000 zagreb, croatia; e-mail: dvrsaljko@hgi-cgs.hr 2 faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, hr-10000 zagreb, croatia. 3 department of geology and palaeontology, faculty of science, university of zagreb, horvatovac 102a, hr-10000 zagreb, croatia. abstract miocene sediments rimming the palaeozoic–mesozoic–palaeogene rocks, form žumberak mt. and the samoborsko gorje mts. spatial analysis of the setting and development of the surface miocene stratigraphy, at the marginal areas of the žumberak and samoborsko gorje mts., allows four palaeogeographic areas to be distinguished: žumberak, plešivica–sveta jana, samobor–sveta nedelja and grdanjci. in the miocene deposits (totaling 350 m), within the area of žumberak, coarse-grained clastics from deltaic deposits of pannonian age prevail. here only, 50 m of sediments of pliocene–pleistocene age overlie the miocene deposits whereas mesozoic carbonates represent the basement. the plešivica–sveta jana area is characterized by a 600 m sequence of miocene deposits, mainly overlying triassic dolomites, where finely-grained layers of marls and silts prevail. in this area, miocene successions from the badenian to the pontian are characterized by a continuity of sedimentation with an inherited depositional environment. in the area of samobor–sveta nedelja, the basement is diverse: triassic dolomites, volcanogenic–sedimentary complex of cretaceous age and a clastic–carbonate complex of palaeogene age. the miocene succession shows a regressive trend from the badenian to the pontian and the total thickness is estimated at 400 m. the area of grdanjci differs considerably from the other miocene palaeorelief. an approximately 50 m-thick series of coarsegrained clastics with coal is distinguished, of unclear stratigraphic age (ottnangian?). miocene sediments of the grdanjci area are represented by both a transgressive type of conglomerates and shallow water limestones of badenian age, with a total thickness of about 100 m. the development of the miocene stratigraphy of the žumberak and samoborsko gorje mts. is generally correlative with that in the other parts of the pannonian area, though it does exhibit local variations. comparison of the miocene palaeorelief of žumberak mt. with the samoborsko gorje mts., together with neighbouring areas, enabled wider correlation with other parts of northern croatia, and the more distant western and central paratethys. 134 geologia croatica 58/2 the main method used in exploration was reconstruction of the miocene palaeogeography using palaeontological and petrographic analyses of the sedimentary successions, and geological mapping of the area. there are relatively few papers published regarding the miocene deposits of the žumberak and samoborsko gorje mts. gorjanović-kramberger (1894) first detailed the entire geology of the miocene. šuklje (1929) investigated the “mediterranean deposits” in more detail (the term is from gorjanovićkramberger, 1894), describing the rich community of molluscs from zaprešić brijeg in the samoborsko gorje mts. pavlovsky (1957, 1960) determined new elements of the molluscan fauna from the same locality, comparing these deposits with “grund’s layers” of tortonian (badennian) age in the vienna basin. bajraktarević (1978), determined the late tortonian (late badenian) age of sediments from zaprešić brijeg locality on the basis of the foraminiferal community. after years of exploration, including part of the b a fig. 1 location map: a) position of the study area within croatia; b) study area with main geological columns: 1 – slapno; 2 – draganići (= draganići structure); 3 – ozalj; 4 – krnežići; 5 – krašić; 6 – hrženik; 7 – kučeri; 8 – dol (= žumberak); 9 – toplica–2; 10 – toplica–1; 11 – miladini; 12 – malunje; 13 – jurjevčani–2; 14 – jurjevčani–1; 15 – podgrađe podokićko; 16 – kladje–1; 17 – kladje–2–3; 18 – vrhovčak (= samoborsko gorje mt.); 19 – podsusedsko dolje; 20 – kostanjek; 21 – bizek (= sw part of medvednica mt.); ka–2 – karlovac–2 well (= karlovac depression). 135 vrsaljko, p avelić & b ajraktarević: s tratigraphy and p alaeogeography of m iocene d eposits... fig. 2 g eological m ap of m iocene deposits of žum berak m t., the s am oborska gora m ts. and the s w part of m edvednica m t. (m odified according to š ik ić et. al., 1979; b a s c h , 1995; v r s a ljk o , 2003). ~ ~ o ? ¥ 1 51an i 't'a.~ i', draganici structure / • / mt. i samobo rsko cd i • i d q, holocene d d ?pi.q, ? pliocene pleistocene d d ·' m upper pliocene d d m: upper ponuan d d m:.m~ upannonian-u.pontian m d m~-z u-r-upper pannonian § ,; d m=m; l. pannonian l. pontian d d ii' low.r pannonian d • • d ffika-2we1l ~ 'w " ~ @ -. l!or.le legend: m, sarmeuan ", sarme.uan m' • up~r bad.,lan 1 mz ? otinangian .g palaeogene transgressive boundary normal boundary main faun linlmll11em subsided block k,-k. c~oul l...l..l...i reverse fault j,.jz jurassic .., .. r,-t. triassic folded sedimenbl ·u permian --@ • i;~ " e9 ka-2 deep well • 3 referent geok)gical column • 5 additional geological column • paiaaogeographlcal bondary palaeogeographical area: cd 2umberak ® pleseviga-5v. jana @ samobor-8v. nedewa @ grdanjci 136 geologia croatica 58/2 area of žumberak mt. and the samoborsko gorje mts., šikić et al. (1978, 1979), published a general geological map, giving an overview of events from the palaeozoic to the quaternary. bajraktarević (1980) investigated the micropalaeontology of the samoborsko gorje mts., and documented the existence of badenian sediments at more localities. velić (1983) provided a new contribution to the neotectonic relationships and development of this area during the miocene, based on geological, geophysical and geomorphological investigations of the western part of the sava depression. pikija et al. (1984) explored the miocene deposits of jurjevčani (southeast slopes of the plešivica mt.; fig. 2) in detail, together with examining the hydrocarbon potential of the wider area of žumberak mt., providing detailed lithological and stratigraphic descriptions of miocene outcrops. pikija et al. (1989) investigated “biolithitic and adjacent carbonate facies of the sarmatian” of the ozalj–krašić area. tomljenović & csontos (2001) investigated neogene–quaternary structures of the žumberak mt. slopes and the karlovac basin itself, on the basis of geophysical and other data, whereas tomljenović (2002) gave a detailed outlook on the geodynamic development of smaller individual neogene basins in the region of the medvednica and samoborsko gorje mts. vrsaljko (2003) within the frame of the project “geological map of the republic of croatia, 1:50,000” studied the miocene sedimentary rocks in detail, and on the basis of a rich molluscan community from žumberak mt. and the samoborsko gorje mts., suggested the zonal distribution of miocene sediments. 2. results 2.1. stratigraphy of žumberak mt. and the samoborsko gorje mts. a number of localities with numerous outcrops were taken into consideration and geological columns were made from the south towards the north: draganići, slapno, ozalj, krnežići, krašić, hrženik, kučeri, dol, toplica, miladini, malunje, jurjevčani, podgrađe podokićko, kladje and vrhovčak (fig. 2). the petrographic and palaeontological composition of sediments has also been analyzed. the spatial distribution of individual miocene units, together with their relationship to basal and overlying strata is presented on a geological map (fig. 2). four miocene palaeogeographic areas are singled out (fig. 4): (1) žumberak, (2) plešivica–sveta jana, (3) samobor–sveta nedelja, and (4) grdanjci. 2.1.1. žumberak 2.1.1.1. the miocene basement the miocene basement consists of triassic dolomites and cretaceous limestones and clastics (fig. 2). dolomites are strongly tectonized as shown in the abandoned slapno quarry. in the ozalj area (fig. 2) the basement is composed of cretaceous–palaeogene carbonates and flysch deposits (šikić et al., 1978, 1979; herak, 1986). 2.1.1.2. sarmatian oldest miocene horizons transgressively overlie the carbonate–flysch cretaceous basement and are of sarmatian age (figs. 2, 4 and 8). between the basement and overlying pannonian clastics, 1–5 m thick clinoform bodies of matrix-supported breccia–conglomerates are found, with recurrent blocks of limestones up to 1 m thick. coarse-grained clastics were most probably deposited from gravity flows on the very steep slope (vrsaljko, 2003; vrsaljko et al., 2003). near the krašić locality, biolithitic rocks of sarmatian age were found, lying directly on pre-miocene basement which consists of triassic dolomites (pikija et al., 1989). the sarmatian age is proven by molluscs (pirenella picta and modiolus incrassatus) which occur among the bioclastic grains and within the sandy matrix of deposits originating in marine environment of reduced salinity (vrsaljko, 2003; vrsaljko et al., 2003). 2.1.1.3. pannonian pannonian sediments transgressively overlie the sarmatian deposits (figs. 2, 4, 9 and 10). at slapno, these are represented by silts and silty marls with coal-rich clastics, whereas by ozalj these are calcarenites (figs. 2, 4 and 9). rare ostracods (hungarocypris auriculata, hemicytheria reticulate and others), determined from this level, indicate an early pannonian age (vrsaljko et al., 2003). conglomerates of proximal deltaic environments, and/or sandy–silty marls of a lacustrine sublittoral, i.e. of prodeltaic environment (ozalj/slapno; figs. 2, 4 and 10), follow in the succession. the molluscan community found in marls (congeria partschi, c. zsygmundi, c. pancici and lymnocardium sp.) indicates a late pannonian age (vrsaljko, 2003; vrsaljko et al., 2003). the conglomerates are succeeded by calcarenites with a mixed fluvio–lacustrine community of molluscs (assemblage: theodoxus–congeria–melanopsidae–lymnocardiidae; vrsaljko, 2003; locality krnežići, figs. 2 and 4). similar deposits with an analogous community of molluscs were described from the vienna basin by papp (1953). in the sandstones an in situ mollusc community, indicates the youngest late pannonian level. 2.1.1.4. pontian lower pontian sediments were determined in the vicinity of krašić (figs. 2 and 11) based on paradacna abichi found in silty marls (vrsaljko, 2003). late pontian communities of molluscs in which congerias and limnocardiidae dominate (congeria rhomboidea, c. croatica, lymnocardium mayeri and others) were recently discovered by investigations in the vicinity of petrovina (southeast from krašić; figs. 2 and 11) where sediments are predominantly sands and silts (vrsaljko, 2003). 137 vrsaljko, p avelić & b ajraktarević: s tratigraphy and p alaeogeography of m iocene d eposits... fig. 3 p alaeogeographic m ap of žum berak m t. and the s w part of m edvednica m t. (from v r s a ljk o , 2003). <"'\ legend: . _ -?m2 m" m, .-t-. .,. -~ '1 -) -~ _ . _ palaeogeographical area boundary i g)®@@ palaeogeographical area ~ transgression-regression trends , ats'ko· , -' " -("'. /'$j:>-" , m, • / ' $<0'-\\fakovac, "'-' _ deoresslon ~ present basement-miocene boundary kf/~ ~ reverse fault ~ strike-slip faul t 138 geologia croatica 58/2 2.1.1.5. pliocene and pleistocene the sediments of pontian age are most often overlain by pliocene–pleistocene deposits, clays and gravels with coal intercalations. in the vicinity of brezarić (south of krašić; figs. 2 and 4), coal layers were discovered containing a community of freshwater gastropods (melanopsidae) determining the pliocene age (vrsaljko, 2003). 2.1.2. plešivica–sveta jana 2.1.2.1. the miocene basement the basement deposits are mainly represented by triassic dolomites, whereas in the area of toplice, the premiocene rocks are cretaceous limestones (fig. 2). at plešivica mt., the current structural setting of the triassic complex indicates that it is partly reversely uplifted onto miocene deposits (badenian and sarmatian; see figs. 2 and 3). 2.1.2.2. upper badenian badenian sediments are most clearly observed in the wider area of jurjevčani (southeastern slopes of plešivica mt.; figs. 2 and 7). the lowest parts of the badenian are represented by marine shallow water conglomerates and algal limestones on which the deep-water marls were deposited. a badenian age is proven by the abundant macrofauna (corbula, nucula, pecten, etc.) the uppermost part of the badenian deposits is characterized by horizontal lamination in marls and clays with lesser proportions of biogenic components (fig. 4). 2.1.2.3. sarmatian sarmatian layers are conformable on the badenian with no visible traces of any lithological discontinuity. foraminifera, ostracod and mollusc (ervilia, musculus, modiolus, cardidae and others) communities define the badenian–sarmatian biostratigraphic boundary, and the transition from an open marine environment towards a basin with reduced salinity (vrsaljko, 2003). the lower sarmatian is mainly composed of marls and clays, with sporadic, cm-thick intercalations of calcarenites and conglomeratic sandstones. the middle parts of the sarmatian are characterized by the presence of varve-like laminated marls and clays, with scarce intercalations of sandstones which could have been deposited from turbidity currents (fig. 4). rhytmites composed of laminites, limestones and sandstones comprise the upper parts of the sarmatian, while in the uppermost ten metres layers of marls and clays dominate, varying in thickness from millimetres to centimetres. 2.1.2.4. pannonian the lower pannonian layers, known as the “croatica limestones” are not developed in this area, possibly because the depositional environment was deeper at that time (figs. 2 and 9). rare forms of brackish ostracods are the only basis for suggesting an early pannonian age. these occur in the approximately 20 m thick lacustrine marl facies from deeper (sublittoral) waters. the boundary with the underlying sarmatian layers is conformable with the inherited depositional environments (figs. 4 and 8). upper pannonian layers are most often developed in the marls, silts and sands facies, which is dominated by massive marls. the marls are poorly fossiliferous and well bioturbated. in the middle and upper part of the upper pannonian sequence (approximately 200 m total thickness, fig. 4) conglomerates of lens-like geometry occur within the marls (region of toplice and sveta jana; figs. 2 and 10). these are probably a consequence of a fluvial influx of terrestrial material from the immediate hinterland into the deeper lacustrine environment. 2.1.2.5. pontian pontian deposits are approximately 130 m thick (fig. 4). lower pontian sediments are represented by massive marls and occasionally silts, as an extension of the pannonian sedimentation cycle. the age is inferred from a scarce brackish community of ostracods (vrsaljko, 2003). the significant occurrence of sands and silts indicates that the late pontian was characterized by variable depositional environments from a lacustrine basin into a deltaic environments (figs. 4 and 11). in the uppermost parts of the pontian sands a recognizable community of molluscs prevail (coarse congeria and lymnocardiidae – vrsaljko, 2003). 2.1.2.6. pliocene and pleistocene the pontian and frequently the pannonian layers are covered by mostly gravels and clays, which are of uncertain stratigraphic position, and could be of pliocene and/ or pleistocene age (figs. 2 and 4). the upper boundary between the miocene layers and their overlying strata is unconformable, i.e. erosional. 2.1.3. samobor–sveta nedelja 2.1.3.1. the miocene basement miocene basement rock types are very variable in samobor–sveta nedelja area. triassic dolomites are the most common, but there are localities where the basement is composed of volcanogenic–sedimentary complexes of cretaceous age, or palaeogene limestones and clastics (kladje and svetonedeljski breg localities; fig. 2). the cretaceous and palaeogene basement is uplifted along the “zagreb–balaton” fault, which explains how these rocks most probably came to the surface forming land areas during miocene times (šikić & basch, 1975; tomljenović & csontos, 2001). lithophaga sp. in basement rocks provides evidence for the existence of the badenian coastline (e.g. svetonedeljski breg locality; figs. 2 and 7). 2.1.3.2. upper badenian the oldest miocene sediments in this area are of badenian age (fig. 2). algal limestones were most com139vrsaljko, pavelić & bajraktarević: stratigraphy and palaeogeography of miocene deposits... lo w er u pp er u pp e r u pp er lo w e r u pp er fig. 4 lithostratigraphic columns of palaeogeographic areas of žumberak mt. and the samoborsko gorje mts.: (1) žumberak; (2) plešivica– sveta jana; (3) samobor–sveta nedelja; (4) grdanjci. 140 geologia croatica 58/2 monly the first deposits on the older palaeorelief, followed both laterally and vertically by silty marls (fig. 7). the limestones contain numerous organisms (including algae, bryozoa, molluscs, and foraminifera) which define the shallow marine environment. marls contain an abundant mollusc community (including pecten, nucula, macoma, tellina etc.), which characterize the deep-water sediments (vrsaljko, 2003). the uppermost part is represented by laminated marls with cmthick laminae and a sparse fossil community. considerable deepening of the area during the badenian probably led to deposition of a thicker sequence of marls (fig. 4). 2.1.3.3. sarmatian sedimentation continued conformably on badenian deposits in reduced salinity environments (pikija et al., 1984). the boundary between the two stages can only be defined biostratigraphically, on the basis of foraminifera and molluscs (vrsaljko, 2003). in the area of svetonedeljski breg, well developed sarmatian sediments can be found, dominated by distinctly laminated marls. occasionally, especially in the lower part of the sarmatian deposits, metre-thick sand beds occur which are probably deposited from gravity flows (figs. 4 and 8). sandstones consist of biogenic detritus, mainly redeposited from badenian rocks. the total thickness of sarmatian deposits is approximately 70 m. 2.1.3.4. pannonian in the samobor–sveta nedelja area, lower and upper pannonian layers can be distinguished (fig. 4). lower pannonian deposits are approximately 30 m thick, and are represented by clayey limestones and marls where hard limestones, with a poor shallow-lacustrine community of molluscs dominate (radices, planorbises, valvatae and limnocardii). limestones, known as “croatica beds” (jenko, 1944), continually and conformably overlie sarmatian marls and are to be found northwest of svetonedeljski breg (around rakovica, south of samobor; figs. 2 and 9). the late pannonian sub-stage is represented by ~100 m of sediments where massive marls dominate (figs. 4 and 10). occasionally, intercalations of decimetre-size gravel occur. a community of tiny brackish molluscs from a deeper lacustrine environment is defined in the marls (congeriae and limnocardii; similar to müller et al., 1999). the boundary between lower and upper pannonian deposits is marked by a gradual transition from limestone to calcite-rich marl with a considerably different fossil content (fig. 4). 2.1.3.5. pontian scarce outcrops of pontian age only occur in the surroundings of rakovica and molvice (south of samobor; figs. 2 and 11), and their estimated thickness is ~80 m. the lower pontian rocks are mainly massive, bioturbated silty marls with tiny molluscs (limnocardii and congeriae), while sands and silts, together with a community of thick-shelled molluscs (congeriae), conformably follow, indicating a late pontian age (fig. 4). 2.1.3.6. pliocene and pleistocene miocene deposits are mainly covered with younger sediments, possibly of pliocene–pleistocene age (figs. 2 and 4). the uppermost ones consist of gravels, clays, and reddish silts which are probably the sediments of fluvial and lacustrine environments. 2.1.4. grdanjci 2.1.4.1. the miocene basement the miocene basement deposits of grdanjci (west of samobor; figs. 2 and 6) consist of rocks previously dated as palaeozoic, while šikić et al. (1978, 1979) determined them as being of mesozoic age (mostly triassic). the specific feature of this area is the lack of sarmatian, pannonian and pontian sediments (figs. 2 and 4). 2.1.4.2. ottnangian? the oldest miocene deposits unconformably overlie the basement (šikić et al., 1978, 1979). by stratigraphic correlation with very similar deposits (gravels, sands, silts and coal) occurring in north croatia, they are defined as fresh-water “helvetic”, meaning they could belong to the ottnangian. the assumed thickness of these sediments is about 50 m. 2.1.4.3. upper badenian the contact of the badenian with older clastic sediments (?ottnangian) has not been observed. gravels, silts, and coal intercalations comprise the lower parts (šikić et al., 1979). this package of deposits probably represents the products of terrestrial deposition immediately before the late badenian transgression (figs. 4 and 7). they are overlain by silts and sands rich in malacofauna, defining them as “tortonian” (šuklje, 1929; pavlovsky, 1957, 1960; bajraktarević, 1978), i.e. of badenian age. due to a lack of better outcrops this opinion cannot be proven, i.e. deposits cannot be biostratigraphically investigated in detail. biogenic limestones from shallow marine environments are the most widespread sediments in the upper parts. these are most clearly visible in the region of otruševac (southwest of samobor; figs. 2 and 7). predominance of biogenic limestones in the uppermost parts of the column suggest gradual formation of shallows by the end of the badenian. badenian sediments are approximately 100 m thick. 2.1.4.4. holocene gravels and clays, are most probably holocene sediments overlying miocene deposits, primarily those of badenian age (figs. 2 and 4). sediments of sarmatian, pannonian and/or pontian have not been determined on the surface in the grdanjci area. 141vrsaljko, pavelić & bajraktarević: stratigraphy and palaeogeography of miocene deposits... 2.2. stratigraphy of neighbouring area the miocene deposits of žumberak mt. and the samoborsko gorje mts. have been compared to the draganići structure (~10 km north of karlovac), the south-western part of medvednica mt. (surrounding podsused), and the karlovac–2 well (approximately 10 km ne of karlovac) (figs. 1 and 2). the terrains and objects mentioned are those closest to the study area; however, each represents a unique individual geological unit (figs. 1–3 and 5). 2.2.1. the draganići structure north-west of draganići a gently uplifted structure has been observed (fig. 1). the core consists of miocene strata and is rimmed with pliocene–pleistocene sediments (fig. 2). towards the southeast, the karlovac depression is located with exposed marshland to lacustrine pleistocene–holocene sediments. the oldest miocene sediments are of sarmatian age, and are about 50 m thick. laminated marls and silts dominate, whereas in the lower parts metre-thick intercalations of sandstones occur (figs. 5 and 8). a sparse community of foraminifera is observed in the marls, but there are no macrofaunal remains (vrsaljko, 2003). some beds are heavily disturbed by synsedimentary sliding. in fault-contact with the sarmatian deposits, the pannonian marls have an assumed thickness of ~70 m (fig. 2). their age is determined as late pannonian, based on fig. 5 lithostratigraphic columns showing miocene deposits from neighbouring areas – karlovac–2 well and sw part of medvednica mt. for legend see fig. 4. 142 geologia croatica 58/2 a poor ostracod community and rare tiny limnocardids (vrsaljko, 2003). the uppermost part of the miocene sediments consists of silts and sands ~50 m thick (fig. 5). coarse congeria shells determine a pontian age (vrsaljko, 2003). the transition from pannonian marls to pontian silts is most probably gradual (figs. 10 and 11). miocene sediments are covered by gravels, sands and clays, probably of pliocene–pleistocene age (figs. 2 and 5). 2.2.2. the karlovac–2 well this well is 4145 m deep (fig. 5) and comparison of the cores with the existing sedimentary column allows some reinterpretation of the stratigraphic sequence. the boundary between mesozoic carbonates and clastics of palaeogene in the pre-miocene basement, and miocene rocks can be located at approximately 2500 m depth (fig. 5). the oldest miocene sediments are represented by an ~800 m thick series (from about 1750 to 2500 m), represented by the intercalation of conglomerates, siltstones, shales and sandstones (fig. 5). these sediments when correlated with surface rocks could belong to the fresh-water ottnangian and not to the “oligo–miocene– egerian” series as previously thought (tomljenović & csontos, 2001). foraminifera determined from limestones at 1734– 1738.7 m depth, indicate a karpatian to early badenian age (m. miknić, pers. comm. 2005). it is very probable that a common sedimentary basin in the karlovac depression had already been formed at this time, and the first miocene, i.e. karpatian transgression occurred (figs. 6 and 7). the core from the upper interval (1641–1645 m) is a silty marl with foraminifera, spiculae and mollusc shells (pectinacea), most likely of badenian age (vrsaljko, 2003). cores from two intervals (1392–1394 m and 1462–1467 m) comprise laminated marls with fish remains which were determined as a feature of surficial sarmatian sediments at outcrop. from 1340–1343 m the core is represented by hard marls with ostracods and relics of terrigenous macroflora, and is most probably of pontian age. 2.2.3. the south-western part of medvednica mt. the miocene of the sw part of medvednica mt. is largely different from its other parts. according to previously published papers, neogene development is known as the “doljanski miocene”, being different from the “čučerjenski” and “zelinski” types (kochanskydevide, 1944; šikić, 1967, 1968; kranjec et al., 1973; kochansky-devide & bajraktarević, 1981; basch, 1983a; vrsaljko, 1997, 1999). on the sw part of the medvednica mt., the base of miocene sediments mainly consists of triassic dolomite with a clearly visible palaeorelief (figs. 2 and 5). fig. 6 palaeogeography during the early miocene (?ottnangian) in the wider area of žumberak mt. and the samoborsko gorje mts. legend: 1 – fresh-water clastics (? fluvial); 2 – pre-miocene basement; 3 – sw boundary of miocene outcrops. 143vrsaljko, pavelić & bajraktarević: stratigraphy and palaeogeography of miocene deposits... upper badenian breccias and conglomerates transgressively overlie the basement. the triassic dolomites are overlain by shallow marine algal limestones (pikija et al., 1995), with lateral and superimposed deposition of shelf and/or lagoonal marls. the uppermost 10 m of the badenian is characterized by weakly fossiliferous, laminated marls and clays (fig. 5). the total thickness of the badenian sediments is about 100 m. sarmatian sediments mainly conformably overlie badenian deposits with no recognized lithological difference. the biostratigraphical boundary can only be defined on the basis of changes in the microand macrofaunal communities between the two stages. the transgressive characteristics of the sarmatian sediments in certain areas are to be expected, e.g. near podsusedsko dolje, where the angular unconformity occurs between the badenian and sarmatian deposits (figs. 2 and 5). most commonly, shallow water badenian limestones underlie the sarmatian clastics, whereas the deepwater marine marls lie beneath the laminated sarmatian marls, which were deposited in a lower-salinity environment (vrsaljko, 1999). in the lower and middle parts of the sarmatian, metre-thick intercalations of coarsegrained clastics are present, whereas in the uppermost parts remarkably well laminated marls dominate (fig. 5). the thickness of the sarmatian sediments is approximately 70 m. lower pannonian deposits (the “croatica beds” – jenko, 1944) are fully developed and are dominated by clayey limestones and marls. the limestones contain numerous ostracods and molluscs suggesting brackish, shallow-lacustrine environments (kranjec et al., 1973; vrsaljko, 1997, 1999). these sediments conformably overlie the sarmatian marls and clays and are about 50 m thick. the upper pannonian “banatica beds” continuously overlie the lower pannonian, with a gradual decrease of carbonate content towards the younger deposits (fig. 5). deposits of the upper pannonian consist mainly of massive, bioturbated marls with deep-water molluscs and ostracods (vrsaljko, 1997, 1999). in the central part gravels and sands commonly occur, as reflections of strong floods on the land (figs. 5 and 10). the uppermost pannonian sediments are represented by massive marls, which are mainly covered by pliocene–pleistocene gravels and clays. the thickness of the upper pannonian beds is estimated at approximately 100 m. 2.3. comparison of the miocene stratigraphy of žumberak mt. and the samoborsko gorje mts. even though the miocene stratigraphy of žumberak mt. and the samoborsko gorje mts. occupies a relatively small area, characterized by expected similarities in development, there are also some differences. these mainly relate to the thicknesses of the miocene deposits; not only to the total thickness, but also the thickness fig. 7 the palaeogeographic situation during the early middle miocene (badenian) in the wider area of žumberak mt. and the samoborsko gorje mts. legend: 1) “coaly series”; 2) shallow water carbonates; 3) slope to basin deposits; 4) sw boundary of miocene outcrops; 5) pre-miocene basement. 144 geologia croatica 58/2 of individual stages of sedimentation. for example, the maximum thickness of miocene deposits is found at plešivica–sv. jana (>600 m; fig. 4), whereas the minimum occurs at grdanjci (~150 m; fig. 4). in the grdanjci unit, clastic sediments have been found which could belong to the ottnangian, as well as coaly silts and biogenic limestones of most probably late badenian age (near otruševec – bajraktarević, 1978, 1980; vrsaljko, 2003; figs. 2 and 7). these are special features of this unit as such sediments are not present in other units of žumberak mt. and the samoborsko gorje mts. in the palaeogeographic area of grdanjci, sarmatian and upper miocene sediments are not developed (fig. 2). additionally, the transition from the sarmatian towards the pannonian is marked by the development of different environments across the wider areas of žumberak mt. and the samoborsko gorje mts. (figs. 2, 8 and 9). while the palaeogeographical area of plešivica–sv. jana remained within a relatively deeper (sublittoral) environment during the early pannonian, shallow-water (littoral) environments formed within the area of samobor–sv. nedelja (figs. 9 and 10). at the same time, in the area of žumberak land existed, which afterward served as the source of clastic material which was deposited in a lacustrine delta (vrsaljko, 2003; vrsaljko et al., 2003; figs. 9 and 10). during the late pannonian in the palaeographic area of žumberak, mainly sublittoral clastics, and to some extent, deep-water marls were deposited, while the areas of plešivica–sv. jana and samobor–sv. nedelja were characterized primarily by deposition of marls of a deeper brackish lacustrine basin with the occasional influx of clastic material (figs. 2 and 10). the early pontian is marked at all three palaeogeographic areas with very similar types of sedimentation. marls prevail with rare occurrences of siltstones (fig. 11), and these are characterized by a scarce macro-faunistic and ostracod community (vrsaljko, 2003). in the late pontian, the basin was infilled, mainly with sandy material, and this is a characteristic of all three areas. sedimentary and petrographic analyses of pontian sediments show the gradual domination of regional influences on sediment source (?alpine), over the local influences (?dinarides), towards the end of miocene (marijan kovačić, pers. comm., 2005). pliocene, pleistocene and holocene compressional tectonics significantly influenced the creation of spatially reduced fresh-water environments in which the material, primarily from local sources, was deposited (horvath, 1995; tomljenović, 2002). fig. 8 palaeogeography during the late middle miocene (sarmatian) in the wider area of žumberak mt. and the samoborsko gorje mts. legend: 1) littoral clastic rocks; 2) basin deposits; 3) sw boundary of miocene outcrops; 4) pre-miocene basement. 145vrsaljko, pavelić & bajraktarević: stratigraphy and palaeogeography of miocene deposits... 2.4.3. karpatian (?) in the karlovac–2 well (1754–1759 m depth) the existence of karpatian sediments is significant (fig. 5), and can be correlated to some extent with similar, neighbouring terrains (i.e. central parts of medvednica mt. – šikić, 1968). 2.4.4. upper badenian upper badenian deposits are often found both in the immediate and broader study, occurring as beds immediately overlying the older basement (figs. 2, 4 and 5). late badenian sedimentation could be interpreted as a consequence of a short, but very intense marine transgression due to eustatic sea level rise with the opening of the connection of central paratethys with the indo–pacific ocean (rögl & steininger, 1984). the most representative exposed sediments are shallow water algal limestones. in some areas, such as the karlovac depression, the first sediments are deep-water marine marls, possibly of badenian age, which continuouslyoverlie karpatian deposits (figs. 5 and 7). 2.4.5. sarmatian sarmatian layers are most often conformable on badenian strata, but in the area of žumberak mt. they also occur as transgressive deposits overlying the mesozoic basement (pikija et al., 1984; vrsaljko, 2003; vrsaljko et al., 2003; figs. 2, 4 and 8). the sar2.4. comparison of the miocene stratigraphy of žumberak mt. and the samoborsko gorje mts. with neighbouring areas 2.4.1. the miocene basement the miocene basement varies a lot over the relatively small area explored, which is a consequence of the mesozoic–palaeogene depositional evolution. at žumberak, the basement is composed of mesozoic carbonates (most often triassic dolomites), while at the samoborsko gorje mts. it consists of palaeozoic–mesozoic–palaeogene carbonates and clastic rocks (fig. 2). in the karlovac–2 well the basement of the miocene rocks consists of palaeogene clastics (fig. 5). in contrast, in the sw part of medvednica mt. the basement is mainly represented by triassic dolomites (see figs. 2 and 5). 2.4.2. ottnangian (?) these sediments, being determined by stratigraphic correlation as ottnangian, are exposed in the samoborsko gorje mts. area (grdanjci unit; figs. 2 and 6), and also occur in the karlovac–2 well. correlation with the surrounding areas of northern croatia (i.e. central part of medvednica mt. – kochansky-devide & slišković, 1978; pavelić et al., 1995) is problematic and questionable. fig. 9 the palaeogeographic situation during the late miocene (early panonian) in the wider area of žumberak mt. and the samoborsko gorje mts. legend: 1) fluvial deposits; 2) deposits of proximal parts of the delta fan; 3) prodeltaic deposits; 4) lacustrine basin; 5) premiocene basement; 6) sw boundary of miocene outcrops. 146 geologia croatica 58/2 matian sequence is characterized by the intercalation of marls and carbonate clastics deposited in a reducedsalinity environment. they are easy to correlate over the wider area of northern croatia because of their lithological characteristics (varve-like) and unique fauna (vrsaljko, 1999, 2003). the end of the sarmatian is characterized by shallowing and emergence, which could be a consequence of the restricted connection to the sea (rögl & steininger, 1984). the presence of land could be a consequence of tectonic movements caused by intraplate stress which overtook the whole pannonian basin at the end of the sarmatian causing its inversion (horvath, 1995; tomljenović & csontos, 2001; pavelić et al., 2003). 2.4.6. lower pannonian the lower pannonian deposits of shallow water lacustrine environments are to be found in the area of southwestern medvednica mt. and samobor–sv. nedelja area (figs. 2 and 9). elsewhere, they are developed in the deep-water marls facies where they could be biostratigraphically determined on the basis of rare occurrence of ostracods. at žumberak, for the clastic development the uppermost part of the late pannonian has been presumed (see slapno and ozalj localities; figs. 2, 9 and 10). 2.4.7. upper pannonian the upper pannonian strata (so-called “banatica beds”) are widespread, and represented by deep-water, lacustrine marls. however, at the south and central parts of žumberak mt. and samoborsko gorje mts., sequences of coarse-grained clastics exist, reflecting occasional flooding of the land. at žumberak, the prevailence of coarse-grained clastics, i.e. the accumulation of terrestrial material in river deltas is significant (fig. 10). these coarse-grained clastics locally occur on žumberak mt. and medvednica mt., and indicate the formation of land, its strong erosion and accumulation of material in the lake (vrsaljko, 1997, 1999, 2003; vrsaljko et al., 2003). 2.4.8. lower pontian lower pontian deposits have only been determined with certainty in the area surrounding krašić, which could indicate deep-water, lacustrine sedimentation (figs. 2 and 11). at the same time, a similar sedimentation regime probably existed within the area of the karlovac depression (surroundings of karlovac–2 well; figs. 5 and 11). elsewhere in the study area, the lower pontian sediments are barely identifiable. only marls and silty marls with very scarce and atypical fossils indicate the development of the early pontian, known as “abichi beds”. fig. 10 palaeogeography during the late miocene (late panonian) in the wider area of žumberak mt. and the samoborsko gorje mts. legend: 1) fluvial deposits; 2) deposits of the proximal parts of the delta fan; 3) prodeltaic deposits; 4) lacustrine basin; 5) pre-miocene basement; 6) sw boundary of miocene outcrops. 147vrsaljko, pavelić & bajraktarević: stratigraphy and palaeogeography of miocene deposits... 2.4.9. upper pontian sediments of the upper pontian are distributed over a wide area of the southeast slopes of žumberak mt. and the samoborsko gorje mts. (figs. 2 and 11). at grdanjci, and on the southwestern parts of medvednica mt., these sediments are either missing, due to their erosion during the plio–quaternary, or are covered by younger layers. they are represented by silts and sands with characteristic coarse-shelled molluscs defining the layers known as the “rhomboidea beds”. 2.4.10. pliocene stratigraphically determined pliocene sediments are found only in the area surrounding brezarić, not far from krašić (figs. 2–4; žumberak area – vrsaljko, 2003). they can be lithologically as well as stratigraphically correlated with freshwater “paludina layers”, which are found near the surface just northeast of the vukomeričke gorice structure (basch, 1983b). 2.4.11. pleistocene and holocene these sediments consist mainly of gravels, clays and silts of unclear stratigraphic affiliation. this series most probably represents young, fluvial–swamp residues (šikić & basch, 1975; šikić et al., 1978, 1979). due to the lack of fossils it is difficult to determine the age of these layers; however, according to superposition, they are classified as pleistocene–holocene. 3. conclusions within northern croatian miocene deposits the areas of žumberak mt. and the samoborsko gorje mts. represent the mere southwestern rim of central paratethys and the pannonian basin. during the miocene, these parts of the northern croatian neogene basin represent, to some extent, a specific area of sedimentation. miocene sediments surround older rocks of žumberak mt. and the samoborsko gorje mts., and are exposed at the surface at ozalj, krašić, sveta jana, plešivica, sveta nedelja, samobor and grdanjci. they can also be observed at the nearby locations – the draganići area, the southwestern part of medvednica mt. and in the subsurface in the karlovac depression, allowing wider correlation of the deposits. spatial analysis of stratigraphic units from the geological map suggests that the terrains of žumberak mt. and the samoborsko gorje mts. can be divided into four palaeogeographic areas. these exhibit common similarities as well as differences in some stratigraphic sections of the miocene: the žumberak mt. (1), plešivica– sv. jana (2), samobor–sv. nedelja (3) and grdanjci (4). the oldest miocene beds are of uncertain age as determined from grdanjci area and at approximately 2500 m depth, from the karlovac–2 well. superposition of the rocks of the clastic complex with coal intercalafig. 11 the palaeogeographic situation during the late miocene (pontian) in the wider area of žumberak mt. and the samoborsko gorje mts. legend: 1) deltaic deposits; 2) prodeltaic deposits – proximal to lacustrine basin; 3) sw boundary of miocene outcrops; 4) pre-miocene basement. 148 geologia croatica 58/2 tions in the grdanjci area is unclear, but signifies freshwater ottnangian deposits. in the karlovac–2 well, deposits of karpatian age are identified which cannot be found elsewhere in the study area. deposits of late badenian age are the most common, representing the base of the miocene on most of the outcrops in the study area. they are mainly composed of algal shallow-water limestones and to a lesser extend marls of shelf and deep-water marine environments. the žumberak palaeogeographical area shows a transgression commenced with sarmatian beds, directly overlying the mesozoic carbonates, which is not the case elsewhere in the study area. the lower pannonian shallow-water carbonates, known as the “croatica beds” are only to be found within the samobor–sv. nedelja area, and could be correlated with similar deposits of the southwestern parts of medvednica mt. elsewhere, these beds are missing, most likely due to significantly different conditions of sedimentation. the upper pannonian beds, known as the “banatica beds”, are found in many places, while a strong terrestrial influence is observed towards the southwestern parts of žumberak mt. and the samoborsko gorje mts. this is demonstrated by increased proportions of clastics, which are most often intercalated with deeperwater lacustrine marls. scarce deeper water lacustrine molluscs and ostracods occur in the marls, which can be compared with typical late pannonian associations in other parts of croatia. the žumberak area is characterized by an increased proportion of coarse-grained clastics in the pannonian. the pontian sediments are less well known since they are mostly overlain by younger deposits. deltaic– lacustrine deposits occur repeatedly, and are classified with uncertainty as upper pontian, whereas lower pontian layers known as the “abichi beds” are rarely determined (near krašić). the miocene sediments are overlain by clastics (gravels, silts, coaly clays) conditionally determined as pliocene, pleistocene and holocene. only in the area south of krašić (žumberak area) pliocene sediments could be unquestionably determined which may correlate with contemporaneous beds known as the “paludina beds”. vertical and lateral distribution of some miocene units in the žumberak mt. and samoborsko gorje mts. shows clear overprint of variable depositional conditions. today, their relationship is largely masked by younger tectonic movements. significant geological variability noticed in the study area enabled interpretation of the palaeogeographic evolution during the miocene (figs. 6–11). some attributes of all the miocene terrains of the žumberak mt. and samoborsko gorje mts. have to be emphasized as they differentiate this area from others in northern croatia: a) clastic, non-fossil beds from grdanjci are questionably determined as fresh-water ottnangian deposits; b) the occurrence of a thick clastic succession (~800 m thick) in the karlovac–2 well, directly overlying palaeogene clastics, which is conditionally determined as being of ottnangian age; c) layers of karpatian age were detected in the karlovac–2 well; d) coal bearing horizons of the area surrounding samobor (vrhovčak), determined with uncertainty as fresh water badenian, directly underlie the upper badenian algal limestones; e) the appearance of sarmatian transgressive layers within the area of žumberak mt. (slapno and ozalj); f) significant thicknesses (about 150 m) of sarmatian beds on the southeastern flanks of plešivica mt.; g) the appearance of a significant thickness (~150 m) of pannonian coarse grained clastics within the area of žumberak mt. (slapno and ozalj); h) the lack of “croatica limestones” in most parts of the study area; i) wide-spread cover of the miocene layers of žumberak mt. and the samoborsko gorje mts., particularly pontian strata. acknowledgements most of data shown in the paper came out of the subproject “clastic–carbonate rocks of the neogene of žumberak mt.” within the project “geological map of the republic of croatia, scale 1:50,000” and is to be found in the archive of the croatian geological survey in zagreb. the approach to cores from karlovac–2 well was enabled through cooperation with mr. željko ivković, m.sc., from ina-naftaplin, plc., to whom we sincerely express our gratitude. for available micropalaeontological analytical data we show appreciation to mirjana miknić, whereas we are grateful to marijan kovačić for useful suggestions on the sedimentary petrology. the graphical appendices are the work of nenad kurtanjek. this paper benefited greatly from reviews by fred rögl and stjepan čorić (austria). 4. references bajraktarević, z. (1978): gornjotortonska starost sedimenata zaprešić-brijega (upper tortonian sediments of zaprešić-brijeg near samobor, north croatia).– geol. vjesnik, 30/1, 63–69. bajraktarević, z. (1980): mikropaleontološka i biostratigrafska istraživanja tortona (badena) nekih lokaliteta samoborskog gorja, plešivice i marija-goričkih brda 149vrsaljko, pavelić & bajraktarević: stratigraphy and palaeogeography of miocene deposits... (micropaleontologic and biostratigraphic investigation of the tortonian (badenian) of some localities of samoborska gora mt., plešivica mt. and marija-gorička brda mt.).– geol. vjesnik, 31, 37–47. basch, o. (1983a): osnovna geološka karta sfrj 1:100.000. tumač za list ivanić-grad, l 33–81 (basic geological map of sfrj 1:100.000. geology of the ivanić-grad sheet).– geološki zavod, zagreb (1980), savezni geološki zavod, beograd, 81 p. basch, o. (1983b): osnovna geološka karta sfrj 1:100.000. list ivanić-grad, l 33–81 (basic geological map of sfrj 1:100.000. the ivanić-grad sheet).– geološki zavod, zagreb (1980), savezni geološki zavod, beograd. basch, o. (1995): geološka karta medvednice (geological map of medvednica mt.).– in: šikić, k. (ed.): geološki vodič medvednice. inst. za geol. istraž. & ina-naftaplin, zagreb. gorjanović-kramberger, d. (1894): geologija gore samoborske i žumberačke [geology of the samoborska gora mt. and the žumberak mt. – in croatian].– rad jazu, 120, 1–82. herak, m. (1986): a new concept of geotectonics of the dinarides.– acta geol., 16/1, 1–42. horvath, f. (1995): phases of compression during the evolution of the pannonian basin and its bearing on hydrocarbon exploration.– marine and petroleum geology, 12/8, 837–844. jenko, k. (1944): stratigrafski i tektonski snošaj pliocena južnog pobočja požeške gore i kasonja brda (stratigraphic–tectonische verhältnisse der pliozänen ablagerungen des süglichen abhanges der požega und kasonja gebirge) [stratigraphic and tectonic contact of southern flanks of the požeška gora mt. and kasonja brda mt. – in croatian and german].– vjestnik hrv. drž. geol. zavoda i hrv. drž. muzeja, 2/3, 89–159. kochansky-devidé, v. (1944): fauna marinskog miocena južnog pobočja medvednice–zagrebačke gore (miozäne marine fauna des südlichen abhanges der medvednica, zagreber gebirge) [fauna of marine miocene of southern flanks of the medvednica mt. and the zagrebačka gora mt. – in croatian and german].– vjestnik hrv. drž. geol. zavoda i hrv. drž. geol. muzeja, 2/3, 171–272. kochansky-devidé, v. & slišković, t. (1978): miocenske kongerije hrvatske, bosne i hercegovine (miozäne kongerien von kroatien, bosnien und herzegowina) [miocene congeria of croatia, bosnia and herzegovina – in croatian and german].– paleontol. jugosl., jazu, 19, 1–98. kochansky-devidé, v. & bajraktarević, z. (1981): miocen (baden i sarmat) najzapadnijeg ruba medvednice (miozän (baden und sarmat) des westlichen randes von medvednica gebirge, kroatien, jugoslawien) [miocene (badenian and sarmatian) of the westernmost rim of the medvednica mt. – in croatian and german].– geol. vjesnik, 33, 43–48. kranjec, v., hernitz, z. & prelogović, e. (1973): prilog poznavanju mlađih tercijarnih naslaga medvednice, sjeverozapadna hrvatska (ein beitrag zur kenntnis jüngerer tertiärschichten des medvednica gebirges, nordwest kroatien) [a contribution to knowledge on younger tertiary beds of the medvednica mt., northwestern croatia – in croatian and german].– geol. vjesnik, 25, 65–99. magyar, i., geary, d.h. & müller, p. (1999): paleogeographic evolution of the late miocene lake pannonian in central europe.– palaeogeography, palaeoclimatology, palaeoecology, 147, 151–167. müller, p., geary, d.h. & magyar, i. (1999): the endemic molluscs of the late miocene lake pannon: their origin, evolution, and family-level taxonomy.– lethaia, 32, 47–60. papp, a. (1953): pannonian molluscs from the vienna basin.– mitt. geol. gesel., 44, 85–222. pavelić, d., šimunić, an., šimunić, al., avanić, r. & kovačić, m. (1995): aluvijalne naslage otnanga – lokalitet vidovec–1 [ottnangian aluvial deposits from vidovec–1 locality – in croatian].– in: šikić, k. (ed.): geološki vodič medvednice. inst. za geol. istraž. & inanaftaplin, zagreb, 152–153. pavelić, d., avanić, r., kovačić, m., vrsaljko, d. & miknić, m. (2003): an outline of the evolution of the croatian part of the pannonian basin system.– in: vlahović, i. & tišljar, j. (eds): 22nd ias meeting of sedimentology, opatija, field trip guidebook, 155– 161. pavlovsky, m. (1957): prilog poznavanju miocenskih gastropoda zaprešić-brijega kraj samobora (ein beitrag zur kenntnis miozäner gastropoden von zaprešić-brijeg bei samobor) [a contribution to knowledge on miocene gastropods of zaprešić brijeg nearby samobor – in croatian and german].– geol. vjesnik, 10, 51–55. pavlovsky, m. (1960): novi elementi faune zaprešićbrijega kraj samobora (neue elemente der fauna von zaprešić-brijeg bei samobor) [new elements within fauna of locality zaprešić brijeg, nearby samobor – in croatian and german].– geol. vjesnik, 13, 213–216. pikija, m., šikić, k. & šikić, l. (1984): miocen na lokalitetima bačuga i jurjevčani, središnja hrvatska [miocene on the locations of bačuga and jurjevčani, central croatia – in croatian].– geol. vjesnik, 37, 65–80. pikija, m., šikić, k., tišljar, j. & šikić, l. (1989): biolititni i prateći karbonatni facijesi sarmata u području krašić–ozalj, središnja hrvatska [sarmatian biolithites and associated carbonate deposits in the krašić–ozalj area, central croatia – in croatian].– geol. vjesnik, 42, 15–28. pikija, m., šikić, k., tišljar, j., vrsaljko, d. & glovacki-jernej, ž. (1995): badenski sedimenti kamenoloma bizek [badenian sediments of the bizek quarry – in croatian].– in: šikić, k. (ed.): geološki vodič medvednice. inst. za geol. istraž. & ina-naftaplin, zagreb, 44–45. rögl, f. & steininger, f.f. (1984): neogene paratethys, mediterranean and indopacific seaways (implications for the palaeobiogeography of marine and terresstrial biotas).– in: brenchley (ed.): fossils and climate, john wiley & sons, chichester, 171–200. šikić, l. (1967): torton i sarmat jugozapadnog dijela medvednice na osnovu faune foraminifera (torton und sarmat 150 geologia croatica 58/2 des südwestlichen teiles der medvednica auf grund der foraminiferenfaunen) [tortonian and sarmatian of southwestern part of the medvednica mt. on the basis of foraminifera fauna – in croatian and german].– geol. vjesnik, 20, 127–135. šikić, l. (1968): stratigrafija miocena sjeveroistočnog dijela medvednice na osnovu faune foraminifera (über die miozänstratigraphie des nordöstlichen teiles des medvednica-gebirges auf grund der foraminiferenfaunen) [the stratigraphy of miocene of northeastern part of the medvednica mt. on the basis of foraminiferal fauna – in croatian and german].– geol. vjesnik, 21, 213–226. šikić, k. & basch, o. (1975): geološka zbivanja od paleozoika do kvartara u zapadnom dijelu zagrebačke regije [geological events from palaeozoic to quaternary in the western part of zagreb region – in croatian].– ii godišnji znanstveni skup sekcije za primjenjenu geologiju, geofiziku i geokemiju, znanstveni savjet za naftu jazu, 69–86. šikić, k., basch, o. & šimunić, a. (1978): osnovna geološka karta sfrj 1:100 000. list zagreb. l33–80 (basic geological map of sfrj 1:100,000.the zagreb sheet).– institut za geološka istraživanja zagreb (1972), savezni geološki zavod, beograd. šikić, k., basch, o. & šimunić, a. (1979): osnovna geološka karta sfrj 1:100.000. tumač za list zagreb l33–80 (basic geological map of sfrj 1:100.000. geology of the zagreb sheet).– institut za geološka istraživanja zagreb (1972), savezni geološki zavod, beograd, 81 p. šuklje, f. (1929): mediteranska fauna zaprešić-brijega u samoborskoj gori [mediterranean fauna in zaprešić brijeg location in the samoborska gora mt. – in croatian].– vijesti geološkog zavoda, 3, 1–52. tomljenović, b. (2002): strukturne značajke medvednice i samoborskog gorja (structural features of the medvednica mt. and samoborsko gorje – in croatian with an english abstract).– unpubl. phd thesis, university of zagreb, 208 p. tomljenović, b. & csontos, l. (2001): neogene–quaternary structures in the border zone between the alps, dinarides and pannonian basin (hrvatsko zagorje and karlovac basin, croatia).– int. j. earth. sci., 90, 560–578. velić, j. (1983): neotektonski odnosi i razvitak zapadnog dijela savske potoline [the neotectonic relations and development of the western part of the sava river depression – in croatian].– acta geol., jazu, 13/2, 26–65. vrsaljko, d. (1997): stratigrafija naslaga panona jugozapadnog dijela medvednice (stratigraphy of the pannonian deposits of southwestern part of the medvednica mt. – in croatian with an english abstract).– unpubl. msc thesis, university of zagreb, 82 p. vrsaljko, d. (1999): the pannonian palaeoecology and biostratigraphy of molluscs from kostanjek, mt. medvednica, croatia.– geol. croatica, 52/1, 9–27. vrsaljko, d. (2003): biostratigrafija miocenskih naslaga žumberačkog i samoborskog gorja na temelju mekušaca (biostratigraphy of the miocene deposits from the žumberak mt. and samoborsko gorje mts. on the basis of molluscs – in croatian with an english abstract).– unpubl. phd thesis, university of zagreb, 143 p. vrsaljko, d., pavelić, d., avanić, r., kovačić, m., miknić, m., basch, o. & bakrač, k. (2003): the late miocene lacustrine transgression on mt. žumberak (western croatia).– in: vlahović, i. & tišljar, j. (eds.): 22nd ias meeting of sedimentology, opatija, field trip guidebook, 163–165. manuscript received september 09, 2004. revised manuscript accepted november 11, 2005. sokac.indd 1. introduction the sample kj–18 contains a rich algal assemblage, which has already been the subject of previous investigations (sokač, 2004; sokač & grgasović, 2004). among numerous sections of various taxa, listed below under the section on stratigraphic position, the species ascribed by jaffrezo et al. (1978) to suppiluliumaella polyreme elliott has also been identified. in about 250 thin-sections made from this sample, this species is represented by over 100 differently oriented sections, some being in a very good state of preservation. these sections show all the main morphological characteristics typical of the genus linoporella steinmann, 1899, but at the same time allow the new species to be determined, because of many well-pronounced species-specific characters. the algal-bearing sample derives from the barremian part of the lower cretaceous sequence, described as megafacies k3 by tišljar et al. (2002), and characterized by an alternation of peritidal–tidal flat, pelletal and stromatolitic limestones, forming shallowing-upward cycles, laterally with carbonate sand bars and with vadose features at the linoporella vesiculifera n.sp., a new calcareous alga (dasycladales) from the upper barremian of mt. biokovo (karst dinarides, croatia) branko sokač top of each cycle. more detailed lithofacies and biofacies characteristics of this part of the analyzed column (containing the sample kj–18) can be found in the papers by tišljar et al. (2002), sokač (2004), and sokač & grgasović (2004). 2. taxonomic description genus linoporella steinmann, 1899, emend. bassoullet et al., 1978, emend. barattolo, 1991 linoporella vesiculifera n.sp. pls. i–iv synonymy 1978 suppiluliumaella polyreme elliott.– jaffrezo, poisson & akbulut, p. 85–86, pl. 3, figs. 1, 4, 7; pl. 4, fig. 5?; pl. 5, fig. 5. origin of the name: the species is named because of the wineskin-shaped ends of the secondary laterals which give a vesiculiferous appearance to the outer surface of the thallus. type locality: mt. biokovo, in a road cut situated approximately in the middle between the vošac mountain hut and the sv. jure peak (1762 m), fig. 1. coordinates: x=6423980, y=4798490. type stratum: the sample with the new alga belongs to the level of light brown, well-bedded, more or less karstified limestone, with bed thickness ranging from 0.3 to 1.2 m. the microfacies types are fenestral, skeletaland oncoid-bearing, intraclastic grainstone and skeletal–peloidal packstone. the allochems include irregular intraclasts, small pellets, micritized skeletons of benthic foraminifera and gastropods, and, less commonly, oncoids, skeletons and bioclasts of dasycladacean algae, and centripetally micritized shell bioclasts. the lithological succession is represented by an alternation of mudstone, algal and foraminiferal wackestone, and sporadic occurrences of skeletal–intraclastic grainstone. holotype: oblique section in thin section kj–18/155, figured in pl. 2, fig. 2. isotypes are represented by variously oriented sections, figured in pl. 1, pl. 2, figs. 1, geologia croatica 58/2 119–131 1 fig. 1 tab. 4 pls. zagreb 2005 key words: calcareous alga, dasycladales, genus linoporella, taxonomy, lower cretaceous (barremian), dinarides, croatia. croatian geological survey, sachsova 2, po box 268, hr-10000 zagreb, croatia; e-mail: amartek@hgi-cgs.hr abstract according to all the main characteristics, the new species belongs to the genus linoporella. at the species-specific level, linoporella vesiculifera n.sp. is characterized by visibly widened distal ends of the secondary branches, which gives a vesiculiferous appearance to the outer surface of the thallus. the distal widenings are spherically or conically shaped and open outwards in a funnel-like form. a short review of the taxonomic validation of some linoporella species is also given. the new species is derived from the barremian deposits of mt. biokovo (central dalmatia, croatia). 120 geologia croatica 58/2 3–8, and plates 3 and 4. the original material is kept at the croatian geological survey (former institute of geology), zagreb. diagnosis: the species is characterized by a cylindrical thallus bearing euspondyle primary laterals. laterals are clearly divided into primaries and secondaries. each phloiophorous primary lateral bears a tuft of 3 secondaries, which have strongly widened distal ends. these distal widenings form gentle bulges of wineskin-shaped chamberlets (vesicles) with funnel-shaped, outward opened, endings on the outer surface, which give the species its most typical characteristic. description: the thallus is cylindrical, unbranched, with a clearly delineated, even, inner edge (pl. ii, figs. 2, 4, 8). the outer surface is characterized by small bulges of the bubble-shaped distal ends of the secondary laterals, with the outward opened, funnel-shaped terminations (pl. i, figs. 4, 6, 8; pl. ii, figs. 1–3). in specimens with a well-preserved inner edge, e.g. those figured in pl. ii, figs. 6, 8 and pl. iii, figs. 1, 5, 8, the axial cavity occupies about 30–40% of the total diameter of the thallus. the calcareous skeleton is composed of secondary mosaic calcite. the species is clearly euspondyle: primary laterals are arranged into regularly distributed rows of whorls, which are clearly visible in longitudinal and oblique sections (pl. i, fig. 2; pl. iv, fig. 4), and, as a radial arrangement of laterals, in transverse sections (pl. iv, fig. 9). the laterals are bipartite, clearly divided into primaries and secondaries. the primaries are generally phloiophorous: slender, and more or less clearly widened distally (pl. i, figs. 1, 3). in some cases, their distal widenings acquire a bulbous, head-like shape (pl. ii, fig. 5), or, depending on where the secondaries branch off, a shallow y-like shape (pl. iv, fig. 8). large cavities (pores) of the primaries’ distal swellings facilitate a more intense destruction of the central zone of the calcareous envelope, which produces visible fissures in circular and oblique sections (pl. i, fig. 8; pl. iii, figs. 5, 7; pl. iv, figs. 6, 9, 10). the primaries are directed upwards, more or less inclined to the main axis at an angle of 18–45°. in adjacent whorls, the laterals are arranged alternately, with minor irregularities (pl. ii, fig. 4; pl. iv, fig. 4). three secondaries grow out from the distal ends of the primary laterals (pl. i, fig. 7; pl. iii, fig. 6), though, sometimes, a fourth secondary may perhaps occur. from their starting point, secondary branches diverge from one another and, though generally directed upwards, some laterals of the same tuft may acquire a horizontal position or are bent even slightly downwards (pl. iii, fig. 1). going outwards, they become slightly club-shaped, similar to the primaries, to widen abruptly into wineskin-shaped or conical swellings in the last (distal) third (pl. i, figs. 4, 6, 8; pl. ii, figs. 1–3). immediately below the outer surface a zone (layer) of densely packed, alternately arranged, vesicle-shaped chamberlets are produced by these distal swellings of the secondaries (pl. i, marginal part of fig. 4), which, in turn, give rise to slight bulges on the outer surface (pl. ii, fig. 2; see marginal part of the calcareous envelope), producing a surface covered with warts. the wart-like surface results in weaker calcification, making the outer surface liable to erosion, which may reach down to the base of the distal swellings. the result is a very different aspect of the section (pl. i, figs. 1–3; pl. iii, fig. 1, upper part of the picture). in many descriptions of dasyclad algae, the question was often raised of whether the pores were open or closed on the surface. in this species, regardless of whether the distal swellings are more or less spherical or conical, they bear on their tops funnel-shaped constrictions, fig. 1 (a) general location of the sample kj–18 locality in the croatian territory. (b) simplified map of the area of the central biokovo mt., type locality of linoporella vesiculifera n.sp. 121sokač: linoporella vesiculifera n.sp., a new calcareous alga (dasycladales)... which open outward (pl. i, figs. 6, 8; pl. ii, figs. 1–3). these funnel-shaped openings on the distal ends of bubble-like (vesiculiferous) chamberlets may indicate the existence of trichoblast tufts; some of which, if wellpreserved, may be mistakenly interpreted as third-order laterals (pl. ii, left part of fig. 4). the distal swellings may be supposed to have functioned as depositories of cysts, which would imply the cladosporous affinity of that species, but this cannot be proven with certainty. somme comments on the diagnosis and the emended diagnoses of the genus linoporella steinmann: the main characteristics of the genus linoporella were given by pia (1927). later, they were emended three times by three different groups of authors, as follows: bassoullet et al. (1978): “cylindrically shaped thallus, made up of primary and secondary branches, arranged in whorls. secondary branches present themselves in a bunch, with a slender diameter in relation to their length. primary and secondary branches are more or less oblique to the main axis and lengthened; they are sometimes slightly thickened at their distal end.” dieni et al. (1985) made the above diagnosis more complete: “secondary branches bear tufts of short tertiary branches. calcification normal, around primary and secondary branches, rare and weak around the tertiary branches.” barattolo (1991) added more detail to the above diagnosis in stating that “the tertiary branches are phloiophorous in shape and form a cortex. reproductive organs were probably placed inside the central stem (endosporate-type).” thus, going from the above quotations, the main question, despite indisputable agreements, centers on the interpretation of the existence of the third-order laterals. dieni et al. (1985) base their amendment on the interpretation of the distal widenings of the secondaries, that, in their opinion, indicate the existence of the tertiary laterals and even expand such an interpretation by also applying it to other linoporella species, namely l. elliotti praturlon and l. kapelensis sokač & nikler. barattolo (1991), unfortunately, failed to support his amendment with adequate sections (photographs). bucur et al. (1995, pl. x, fig. 8) figured a linoporella n.sp. 1 with a tangential–longitudinal section of a skeleton fragment, and in the caption of the figure mentions the existence of the r3 laterals, which form the distal cortex. however, the analysis of that section does not appear to provide a reliable argument proving the unquestionable existence of the r3 laterals; what does appear unquestionable are the widenings of the distal ends of the secondary laterals, visible in a part of the longitudinal section. this is also indicated by larger pores in the lower part of the tangential section, at the same time without the pores that would indicate table 1 correlation of biometric parameters of different species of the linoporella genus. all dimensions are given in millimetres. legend: l – maximum observed length; d – outer diameter of the calcareous skeleton; d – inner diameter of the calcareous skeleton; d/d – relationship between inner and outer diameter of the calcareous skeleton; h – distance between whorls; l – length of primary laterals; p – diameter of primary laterals; l’ – length of secondary laterals; p’ – diameter of secondary laterals; px – diameter of the distal ends of secondary laterals; l” – length of tertiary laterals; p” – diameter of tertiary laterals; w – number of primary laterals per whorl; w’ – number of secondaries 122 geologia croatica 58/2 the existence of the r3 laterals. in the present material, sections figured in pl. i, figs. 4, 6, 8, and pl. ii, figs. 1–3, 8, with clearly visible distal widenings and outward oriented funnel-shaped endings in the secondaries, as exit points for the trichoblasts, make the existence of true third-order laterals highly unlikely. the oblique section figured in pl. ii, fig. 4 (left centre of the picture), where one sole lateral, as opposed to the above examples, may be interpreted as suggesting two small excrescences as a possible third row of laterals, seems to be an exception rather than a rule and thus cannot be taken as proof of the existence of the third-order laterals. the sections figured in pl. i, figs. 1–3, 5, 7, pl. ii, fig. 5, and pl. iii, figs. 1–3, 5, 8, in which the outer surface of the thallus is not completely preserved and which lack the distal ends of the secondaries, showing only open widenings, also prove that the interpretation of the third-order laterals, at least in these cases, cannot be based on a firm foundation. finally, the original diagnosis, with the main characteristics as given by pia (1927), together with the amendments given by bassoullet et al. (1978), seems fully sufficient to enable the valid attribution of l. elliotti praturlon, l. svilajensis sokač & velić, l. kapelensis sokač & nikler, as well as the later described palaeogene species l. parva dieni et al. and l. spissa dieni et al., to the genus linoporella. therefore, the question of the existence of the third-order laterals, which need not be eliminated, is not decisive for the taxonomic classification, more so, as the alleged existence of the tertiary laterals rests upon the authors’ interpretation but lacks visible and reliable proof. as to the amendment given by barattolo (1991), it cannot be competently commented on, as the author unfortunately failed to give any illustrations of sections that would have documented his amendment. similarities and differences: the main characteristics – cylindrical, unbranched thallus, slender primary branches arranged in distinct whorls, and bearing a tuft of distally swollen secondaries – of linoporella vesiculifera n.sp. are all characteristic features of the genus linoporella (pia in hirmer, 1927; emend. bassoullet et al., 1978). though a relatively small number of species have been ascribed to that genus, some still remain inadequately known, which, as already pointed out by praturlon (1965), makes a thorough comparison difficult. the earliest described species, linoporella capriotica (oppenheim), for which the measurement values have been more fully presented by barattolo (1991), and l. taurica pcelincev, remain inadequately and poorly illustrated and, thus, difficult to identify with certainty. not only that, but, as pointed out by bassoullet et al. (1978), l. taurica and the form described as macroporella gigantea by carozzi (1955) should be considered to be younger synonyms of l. capriotica. in contrast, farinacci & radoičić (1991) proposed the emendation and validation of carozzi’s species, with a more complete diagnosis, as linoporella gigantea. they based their opinion on comparison with the illustrations of linoporella capriotica as given by oppenheim under the name of triploporella capriotica (oppenheim, 1889, pl. xix, fig. 7; pl. xx, figs. 11–11c) and of those by steinmann (1899, p. 148–149, fig. 13). however, the illustrations given by those authors represent drawings, i.e. graphic interpretations of the external aspect of the thallus and of a fragment of a tangential–oblique section (on which the genus linoporella was established), except for a very unclear section in steinnmann’s pl. xx, fig. 11b. therefore it is deemed necessary to take up the original description of macroporella gigantea, which was established by carozzi (1955, p. 43, fig. 7) on the basis of drawings (graphic illustrations), of variously oriented sections and only one inadequate photograph of a tangential–oblique section of a fragment (of the skeleton), which really does not enable an objectively more adequate description. as for linoporella taurica pcelincev, it too is represented (in the original description), by only one tangential–oblique section of a skeletal fragment (pcelincev, 1925, pl. 2, fig. 5), which, as is also the case with previous examples, does not enable incontestable conclusions to be drawn. in this species, the thirdorder branches have not been mentioned, but it was said to have tiny spores, mostly situated within the distal ends of the channels of the primary laterals. measurements given with the descriptions of the aforementioned species are not only incomplete, but are also largely unreliable, being based on drawings (reconstructions), and therefore cannot be accepted with certainty. therefore the revalidation of the form ascribed to linoporella gigantea (carozzi) by farinacci & radoičić (1991) is also not based on well founded data which would have enabled an objective comparison. for the time being, short of new finds, all three forms – l. capriotica, l. taurica and l. gigantea – remain inadequately known and it seems justifiable to consider the taurica and gigantea species as younger objective synonyms of l. capriotica, as has been proposed by bassoullet et al. (1978). therefore, the comparison of linoporella vesiculifera n.sp. is objectively possible only with those forms ascribed to the genus linoporella, the morphological characteristics and biometrical parameters of which are unequivocally known. these are: l. kapelensis sokač & nikler, l. elliotti praturlon and l. svilajensis sokač & velić. l. vesiculifera n.sp. differs from the tithonian l. kapelensis by several measurement values. the outer diameter of the new species is, on average, one third smaller than in l. kapelensis or, exceptionally, its largest value may just barely reach the minimum value of l. kapelensis. the same relationships hold true for the inner diameter. in the new species, the distance between neighbouring whorls (h) is much smaller and seldom reaches half of the distance in l. kapelensis. also, the laterals in l. kapelensis are much more steeply directed upwards. further differences concern the number of 123sokač: linoporella vesiculifera n.sp., a new calcareous alga (dasycladales)... branches in a whorl, which in l. vesiculifera n.sp. are one third smaller (24–30) than in l. kapelensis. with regard to l. svilajaensis, the measurement values of the new species are approximately in the same relationship as mentioned above with regard to l. kapelensis. an obvious difference between l. vesiculifera and the two aforementioned species, as well as in l. elliotti, concerns the number of secondary laterals, which is 3 in the new species, as distinct from 4–5 in other species. distal ends of the secondary laterals in the new species are strongly wineskin-shaped, with visible short, funnel-shaped openings at the tops, which support the assumed growth of tufts of thin tertiary assimilatory filaments. similarly, praturlon (1965) has also assumed the existence of tertiary laterals in l. elliotti, based on clearly and visibly widened distal ends of the secondary laterals, that are, in that species, more distinctly club-shaped. the palaeogene species, l. parva dieni et al. and l. spissa dieni et al., are distinctly smaller, in addition to other differences with the older species, as mentioned in the original description (dieni et al., 1985, p. 14–15). in these species the question of tertiary laterals also remains open, though their existence may be assumed on the basis of distal widenings on the ends of the secondaries (dieni et al., 1985, figs. 7a–b), which may be considered to represent their distal wineskin-shaped swellings. the new species is distinguished from all other species by a clearly developed cortical layer of wineskin-shaped vesicles (“chamberlets”; pl. i, figs. 4, 6, 8; pl. ii, figs. 1–2, 6), which is, however, prone to easy destruction and therefore is lacking in many specimens (pl. i, figs. 1–2; pl. iii, figs. 1–2). another species-specific characteristic of the new species is the sporadic occurrence of fissures cutting through the central part of the calcareous envelope, i.e. in the zone (layer) of more or less swollen distal ends of the primary laterals. this feature, however, is not present in all specimens, or may be only fragmentarily developed. the first figured sections of l. vesiculifera in jaffrezo et al. (1978, pl. iii, figs. 1?, 4, 7: pl. iv, fig. 5?; pl. v, fig. 5) have been ascribed to suppiluliumaella polyreme elliott. however, the new species differs from s. polyreme, according to the original description, and the sections illustrated (elliott, 1968, pl. 95, figs. 1–5), by the shape of the primary laterals, which are, in s. polyreme, represented by a long and slender stalk, with a pronounced and abrupt distal swelling from which 4–5 rounded cylindrical (phloiophorous) secondaries grow out, as graphically represented by sokač & nikler (1973, table i). the generic attribution of some species ascribed to the genus linoporella, e.g. linoporella? buseri radoičić and linoporella? lucasi cros & lemoine was already questionable in the original descriptions (as indicated by question-marks put after the generic name), though they were included by granier & deloffre (1993) in their list of linoporella species. however, sokač (2001) ascribed l.? buseri to the genus palaeodasycladus, and bassoullet et al. (1978) stated that l.? lucasi has globular terminations of primary laterals, which is in contrast with their elongated shape in linoporella and brings it closer to the genus dissocladella. this also outlines the differences between those species and the new species, and also emphasizes their equivocal taxonomic position. stratigraphic position: linoporella vesiculifera n.sp. is present with numerous sections in the rich algal assemblage in the upper barremian limestones of mt. biokovo. a detailed description of lithofacies and biofacies is given in the papers by sokač & grgasović (2004) and sokač (2004). the algal assemblage accompanying the new species in the sample kj–18 contains the following, more or less abundant, species: salpingoporella muehlbergii (lorenz), s. verticillata (sokač & nikler), s. patruliusi bucur, s. dinarica radoičić, cymopolia velici sokač & nikler, “praturlonella” dalmatica (sokač & nikler), cylindroporella lyrata masse & luperto sinni, biokoviella robusta (sokač), b. gusici sokač, triploporella ?sarda jaffrezo et al., korkyrella texana (johnson), and rare neomeris cretacea steinmann and suppiluilumaella polyreme elliott. benthic foraminifera are, in general, rarer and stratigraphically insignificant, but the first occurrence of palorbitolina lenticularis (blumenbach) immediately above the algal assemblage is important, as it certainly defines the age of the entire algal assemblage, including the new species, as being middle–late barremian. another locality with linoporella vesiculifera n.sp., in southwest turkey (antalya region – jaffrezo et al., 1978), though quite distant, belongs to a level with an identical shallow water carbonate fossil assemblage, thus suggesting the possibility of its occurrence in other carbonate platform environments of southern tethys. acknowledgement this paper is based on samples that were collected by several colleagues who participated in the field work on biokovo mt., and i am particularly grateful to đuro benček and ivo velić. i would like to thank josip tišljar for his sedimentological analysis and lithofacies interpretation. i am especially grateful to the reviewers, marc a. conrad and felix schlagintweit, who critically read the manuscript, indicated some errors, and provided useful remarks that clearly improved the presentation. i have to admit that with regard to some of their suggestions considering the hitherto diagnosis of the genus linoporella, i decided to retain a critical attitude, in order to provoke and support future investigation. 124 geologia croatica 58/2 3. references barattolo, f. (1991): notes on linoporella capriotica (oppenheim) from the early cretaceous of capri.– in: 5th int. symposium on fossil algae, april 7–12, 1991, 4–6, capri. bassoullet, j.p., bernier, p., conrad, m.a., deloffre, r. & jaffrezo, m. (1978): les algues dasycladacées du jurassique et du crétacé [dasycladal algae of jurassic and cretaceous – in french].– géobios, mém. spéc, 2, 330 p., villeurbanne. bucur, i.i., conrad, m.a. & radoičić, r. (1995): foraminifers and calcareous algae from valanginian limestones in the jerma river canyon, eastern serbia.– rev. paleobiol., 14/2, 349–377. carozzi, a. (1955): les dasycladacées du jurassique supérieur du bassin de geneve [jurassic dasycladal algae of the geneve basin – in french]. – ecl. geol. helv., 18, 31–67. dieni, i., massari, f. & radoičić, r. (1985): palaeogene dasycladalean algae from orosei (eastern sardinia).– mem. sci. geol., 3, 1–32, padova. elliot, g. (1968): three new tethyan dasycladaceae (calcareous algae). – palaeontology, 11/4, 491–497. farinacci, a. & radoičić, r. (1991): late jurassic– early cretaceous dasycladales (green algae) from the western pontides, turkey.– geol. romana, 27, 135–165, roma. granier, b. & deloffre, r. (1993): inventaire critique des algues dasycladales fossiles. iio partie: les algues dasycladales du jurassique et du cretacé [inventory of fossil dasycladal algae. 2nd part: dasycladal algae of jurassic and cretaceous – in french]. – revue de paléobiologie, 12/1, 19–65. jaffrezo, m., poisson, a. & akbulut, a. (1978): bey dağlari tipi serilerin alt kretase algleri (bati toroslar, türkiye) [lower cretaceous algae of bey dağlari series (eastern taurides, turkey) – in turkish].– bull. mineral. res. explor. inst. turkey, 91, 75–88, ankara. oppenheim, p. (1889): beiträge zur geologie der insel capri und der halbinsel sorrent [contribution to the knowledge of geology of the capri island and sorrent peninsula – in german].– z. deutsch. geol. ges., 41, 442– 458, berlin. plate i linoporella vesiculifera n.sp. 1–4 oblique sections showing the well preserved peripheral (cortical) zone of wineskin-shaped swellings at the distal ends of secondary branches (fig. 4). fig. 1, kj–18/110; fig. 2, kj–18/92; fig. 3, kj–18/132; fig. 4, kj–18/132; x22. 5 transverse sections, kj–18/223, x22. 6 fragment of an oblique section with visible cone-shaped widenings at the distal ends of secondary branches. kj–18/56, x34. 7 fragment of an oblique section passing into a tangential one. outer zone of vesicles is partly preserved. in the tangential part of the section (upper part of the figure) the growth of three secondaries may be perceived. kj–18/217, x22. 8 transverse, somewhat oblique sections, with a well preserved peripheral zone of vesicles. on the outer side of individual vesicles short tubular extensions can be observed, open toward the exterior. kj–18/208, x22. 125sokač plate i 1 2 3 4 5 6 7 8 126 geologia croatica 58/2 pcelincev, v. (1925): hydrozoen und dasycladaceen aus den mesozoischen ablagerungen der krim [hydrozoans and dasycladaceans from the mesozoic deposits of crimea – in german].– trav. soc. nat. leningrad, 55/4, sect. geol. min., (refer. 85–86), leningrad. pia, j. (1927): thallophyta.– in: hirmer, m.: handbuch der paleobotanik, i. oldenbourg, münchen und berlin, 31–136. praturlon, a. (1965): a new linoporella (dasycladacea) from middle cretaceous of marsica (central apennines).– geol. rom., 4, 1–6, roma. sokač, b. (2001): lower and middle liassic calcareous algae (dasycladales) from mt. velebit (croatia) and mt. trnovski gozd (slovenia) with particular reference to the genus palaeodasycladus (pia, 1920) 1927 and its species.– geologia croatica, 54/2, 133–257. sokač, b. (2004): on some peri-mediterranean cretaceous dasyclad species (calcareous algae; dasycladales) previously assigned to different genera.– geol. croatica, 57/1, 15–53. sokač, b. & nikler, l. (1973): calcareous algae from the lower cretaceous of the environs of nikšić, crna gora (montenegro).– pal. jugoslav., 13, 57 p., zagreb. sokač, b. & nikler, l. (1973): linoporella kapelensis n.sp. (dasycladaceae) from the tithonian of mt. velika kapela.– geol. vjesnik, 25, 65–71. sokač, b. & velić, i. (1976): linoporella svilajensis n.sp. (calcareous algae, dasycladaceae) from the upper jurassic–lower cretaceous limestone of mt. svilaja, southern croatia (dalmatia).– geol. vjesnik, 29, 173–179. sokač, b. & grgasović, t. (2004): megaporella nikleri n.sp. new calcareous alga (dasycladales) from the upper barremian of mt. biokovo, croatia.– riv. ital. paleont. strat., 11/3, 651–658, milano. steinmann, g. (1899): über fossile dasycladaceen von cerro escamela, mexico.– bot. ztg. 57, 137–154, leipzig. tišljar, j., vlahović, i., velić, i. & sokač, b. (2002): carbonate platform megafacies of the jurassic and cretaceous deposits of the karst dinarides.– geol. croatica, 55/2, 139–170. manuscript received june 1, 2005. revised manuscript accepted november 11, 2005. plate ii linoporella vesiculifera n.sp. 1–2 oblique section; holotype – fig. 2. the section shows the main characteristics of the species: well-developed and clearly visible peripheral zone of vesicles, with their short tubular, outward open extensions on their outer sides, and slight depressions between the vesicles that give rise to their swellings on the outer surface of the thallus. in the central part of the calcareous envelope the incipient development of a fissure can be observed at the level of branching of the primaries. kj–18/155, x22. 3 fragment of an oblique section with the preserved outer part of the calcareous envelope and only secondary branches visible. kj–18/109, x34. 4–5 oblique sections. in fig. 4, the distal zone of the vesicles is completely eroded, in fig. 5 it is partly preserved. fig. 4, kj–18/208; fig. 5, kj–18/78, x22. 6 longitudinal–tangential section. the peripheral zone of vesicles is clearly visible. kj–18/66, x22. 7 oblique section of a specimen with more strongly club-shaped primary branches. 8 transverse section with a clearly visible fissure in the central part of the calcareous wall and the peripheral zone of wineskin-shaped distal swellings of the secondaries. kj–18/77, x22. 127sokač plate ii 1 2 3 6 4 5 7 8 128 geologia croatica 58/2 plate iii linoporella vesiculifera n.sp. 1 oblique–tangential section with clearly visible slender primary branches that divide into the secondaries. in the lower part of the picture, the peripheral zone of wineskin-shaped vesicles is partly preserved. kj–18/111, x22. 2–3 oblique sections. fig. 2, kj–18/130; fig. 3, kj–18/63; x22. 4 (a) transverse section of cylindroporella lyrata masse & luperto sinni; (b) transverse section of linoporella vesiculifera n.sp. kj–18/155, x22. 5 oblique section with clearly visible formation of fissures in the central part of the calcareous envelope (left part of the figure). kj–18/218, x22. 6 fragment of a tangential section. in the upper part of the figure, tufts of three secondary branches are visible. kj–18/126, x34. 7–8 oblique sections. in fig. 7, at the level of branching of the primaries, a secondary circular fissure formed in the middle part of the calcareous wall is clearly visible. figure 8 is an integral section with a visible peripheral zone of wineskin-shaped widenings of the secondaries. fig. 7, kj–18/102; fig. 8, kj–18/228, x22. 129sokač plate iii 1 2 3 4 5 6 7 8 130 geologia croatica 58/2 plate iv linoporella vesiculifera n.sp. 1–3 various oblique sections with clearly visible slender primary branches and a more or less well preserved zone of distal widenings of the secondaries. fig. 1, kj–18/205; fig. 2, kj–18/212; fig. 3, kj–18/132, x22. 4 tangential section with primary branches arranged into visible whorls; kj–18/194, x22. 5 oblique section, kj–18/134, x22. 6 fragment of an oblique section. on the left side, the outer part of the calcareous wall is preserved; on the right side, the formation of the fissure at the level of primary branching is visible. kj–18/129, x22. 7 transverse section, with preserved outer part of the calcareous wall (outward from where the primaries branch off into the secondaries). kj–18/220, x22. 8 fragment of an oblique–tangential section. kj–18/148, x22. 9 transverse section, with visible circular fissure formed at the level in which the primaries branch off, and clearly visible peripheral zone of distal partitions of the secondary branches. the formation of narrow, outwardly directed tubular channels at the distal ends of the “chamberlets” (vesicles) is clearly visible. kj–18/76, x22. 10 transverse, slightly oblique section. kj–18/113, x22. 131sokač plate iv 1 2 3 4 5 6 9 1087 132 geologia croatica 58/2 dreybrodt.indd 129 � ab stra ct when water from the surface, e.g. from a lake, fl ows down through porous carbonate rocks, through a region with high hydraulic conductivity and encounters the water table of a phreatic aquifer, both waters mix by diffusion along their boundary. in a carbonate aquifer, where both surface and phreatic waters are saturated with respect to calcite, mixing corrosion causes renewed dissolution capacity δceq of the carbonate rock in the diffusion-mixing zone, extending from the boundary separating the phreatic water from the surface water encountering it. a numerical model is presented from which the initial change of porosity in such a diffusion-mixing zone is obtained. the initial change of porosity can be calculated from the local distribution of the mixing ratio, and the second derivative of δceq with respect to m. m(x,y)is the spatial distribution of the mixing ratio m= vsurf /(vsuf+ vprh), where the v’s assign the corresponding volumes of surface and phreatic water. the second derivative has been calculated for three geochemical scenarios with differing co2-concentrations of surface and phreatic water by the use of phreeqc-2. the spatial distribution m(x,y) is obtained by using modflow and mt3dms in a modelling domain with constant hydraulic conductivity for various fl ow velocities of the phreatic aquifer. the time scale of cave evolution is estimated from the results. passages of dimensions of about one metre in width and several 10 cm in height, extending in length along the boundary line, where surface and phreatic waters meet, can be created in time scales of 10 000 years. these caves are horizontal with blind ending passages and closely resemble the isolated caves observed in central west florida. keywords: speleogenesis, porous limestone, mixing corrosion, caves, florida evolution of caves in porous limestone by mixing corrosion: a model approach � wolfgang dreybrodt1, douchko romanov2 and georg kaufmann2 1karst processes research group, institute of experimental physics, university of bremen, 28359 bremen, germany; (dreybrodt@ifp.uni-bremen.de) 2institute of geological sciences, fu berlin, malteserstr. 74-100, building d, 12249 berlin, germany; (dromanov@zedat.fu-berlin.de, gkaufma@zedat.fu-berlin.de) doi: 104154/gc.2010.09 geologia croatica 63/2 129–135 6 figs. zagreb 2010 geologia croaticageologia croatica 1. introduction caves in young porous rocks are remarkably different from those in ancient fractured rocks. in the latter, speleogenesis is governed by fl ow along fractures, such as bedding planes and joints, and the matrix conductivity is negligible. consequently, conduits develop along the fl ow directions in these fractures and their walls are solid rock without any porosity. the speleogenesis of these caves was the focus of research for two decades (dreybrodt et al., 2005; dreybrodt & gabrovsek, 2003; palmer, 1991; palmer, 2007; ford & williams, 2007; kaufmann, 2005). caves in porous rocks, however, where the fl ow is not guided along fi ssures but where water is transported by darcy fl ow through the matrix of the rock are different. they are known from young carbonate islands. here mixing of saltwater with freshwater creates fl ank margin caves along geologia croatica 63/2geologia croatica 130 the rim of the island. these isolated caves at the freshwater lens, originate as chambers of moderate size without entrances and exits, mylroie & carew, (1990, 2000, 2003), romanov & dreybrodt (2006), dreybrodt & romanov (2007). in the porous rocks of central west florida, isolated caves are also common. florea (2006), florea & vacher (2004), and florea et al. (2007) have described caves of moderate passage length with blind ending passages. most of these are aligned along nw–se and ne–sw regional discontinuities as revealed from photo lineament features on the surface. the cave passages are not longer than several hundred metres and do not represent an integrated system of passages between inputs and outputs of the aquifer. the walls of these caves consist of porous rock with many small-scale solution features. the principal horizons of cave development appear between 3 m and 5 m; 12 m to 15 m; and 20 m to 22 m above present sea level. these horizons of cave development are related to prior phreatic water tables (florea, 2006; florea et al., 2007) of an unconfi ned aquifer. the caves originate from the following speleogenetic processes. when water from the surface above, e.g. a lake, reaches such a water table, it is already saturated with respect to calcite. it is mixed with the phreatic water, also in equilibrium with respect to calcite. when the co2 concentrations of both waters differ, mixing corrosion boosts the dissolution capacity (dreybrodt, 1988). due to the low hydraulic gradients and the slow fl ow velocity vy, between 10–7 to 10–6 m/s, (hanshaw et al., 1965; davis, 1996) the mixed solution again becomes saturated after several tens of centimetres. therefore initial changes of porosity are restricted to a region close to the boundary line where surface water and phreatic water meet and voids directed vertical to the fl ow of the phreatic water originate. since both bodies of water exhibit darcy fl ow, mixing of the phreatic water with the surface water can only be affected by molecular diffusion and transversal dispersion across the dividing streamline (ds). the diffusion-mixing zone between surface water and the phreatic water zone extends along the z-axis where the surface water enters. mixing corrosion is active in this region and causes increasing porosity along the z-axis where the surface water enters, and down the y-direction along the dividing streamline. this way an isolated cave passage could originate, similar to those passages observed in porous rocks in florida. the conduits are orientated normal to the fl ow direction of water, which has created them. this is similar to the concept of transverse speleogenesis as fi rst suggested by klimchouk (2007), although fl ow is through the matrix of the rock and horizontal, parallel to the water table in contrast to the fl ow ascending through fractures from below in klimchouk’s concept. here, we will investigate how and over what time scale, caves can originate in such a hydrological setup. 2. theoretical background figure 1 represents the geometry of the two domains of phreatic and surface water. it assumes a local input of water from a lake or a river, much larger than the input by meteoric precipitation, which therefore is neglected. such geological settings are reported in lakes in the central lake district, florida, usa, where huge amounts (up to 4 m/year) of water leak down vertically through the bottom of the lake to the water table of the upper floridan aquifer (motz, 1998; motz et al. 2001). the domain of surface water in fig. 1 is idealized and can have other shapes. in any case some kind of a new water table will originate above the former water table of the phreatic aquifer. in this mound of water, fl ow is phreatic and governed by darcy’s law. because in darcyfl ow, fl ow lines can never cross, they must become parallel at the boundary between the water of the underlying aquifer and the surface water or in other words along the dividing streamline. this can be described in the modelling domain shown in fig. 2. the left hand side input boundary idealizes the fi rst fi gu re 1: a) geometry of the hydrological concept: water from a lake at the surface fl ows along some discontinuity with high hydraulic conductivity, down to the water table of an unconfi ned aquifer. the surface water encounters this water table along the z-axis and fl oats with some depth on the phreatic water along the streamline (ds), dividing the two domains of water. both waters are saturated with respect to calcite, but have diff ering co2 concentrations. a diff usion-mixing zone is created along the dividing streamline (ds) of both water bodies. therefore mixing corrosion becomes active creating porosity along the z-axis close to the dividing streamlines. the small rectangle close to the origin of the coordinate system represents the region where the modelling domain is located. b) close up view of a transect showing the rectangle in the x–y plane of fig.1a. due to the infi ltration, a mound of surface water builds up. its upper boundary creates the new water table. its lower border is the dividing streamline (ds) separating phreatic water from surface water. black triangles indicate the fl ow directions. the rectangle md represents the modelling domain, shown in fig.2. a) b) dreybrodt et al.: evolution of caves in porous limestone by mixing corrosion: a model approach geologia croatica 131 reactive transport in such a geochemical situation is described by the dispersion-advection-reaction equations of the species involved, which are ca2+ and co2. these equations read (dreybrodt & romanov, 2007; phillips, 1991) (3) where φ is the porosity of the rock, d is the constant of dispersion, ci the concentration of species i, q→ the darcy – fl ow rate and qi the source term of dissolved material. in the limit of fast dissolution ensuring equilibrium of ca2+ with respect to calcite one gets (4) ceq mix(m,(x,y)), the equilibrium concentration of calcium with respect to calcite is a function of the mixing ratio m. the local distribution of m can be represented by the distribution of a non-reactive tracer with a concentration between 1 and 0. therefore it can be described by a dispersionadvection equation without a source term (5) from equations 4 and 5 qceq and from this the resulting change in porosity dφ/dt in 1/s [volume (m3) of dissolved rock per (m3/s) of the aquifer] can then be calculated by a simple relation (phillips, 1991; romanov & dreybrodt, 2006). (6) m is the molar weight of caco3 and r its density. m(x,y) is the local distribution of mixing in the aquifer. therefore it is only necessary to solve the diffusion – advection equation (6) for mixing in the aquifer. from eq.2 one has d 2 ceq mix/ dm2 = d 2dceq/ dm2. this purely geochemical entity is the second derivative of δceq(m) with respect to m, which can be obtained by use of phreeqc as shown in fig. 3b. to obtain dφ/dt one has to know the mixing ratio m(x,y) and d 2δceq/dm2 as a function of the local coordinates. this method has been successfully applied to the evolution of fl ank – margin caves in the saltwater – freshwater diffusion-mixing zone of coastal carbonate aquifers (romanov & dreybrodt, 2006). encounter of the two water bodies. the y-axis represents the initial part of the dividing streamline. although the velocities could vary locally, in a fi rst approach we assume a constant fl ow velocity vy everywhere in the domain. the corresponding boundary condition is a constant flow rate dis tributed evenly to all cells of the input boundary. the upper and lower boundaries are impermeable to the transport of dissolved ions. this is true in nature only for the upper boundary representing the new water table. the lower boundary in nature is permeable, because the aquifer reaches much deeper. this, however, is only relevant when the width of the diffusion-mixing zone becomes close to the width of the modelling domain. therefore care has to be taken that this does not happen in the model calculations. choosing the width of 1m warrants this. we use cell sizes of 1cm by 1cm. a sharp boundary exists at x = 0.5m, y = 0 m, with calcium concentrations ceq phr for x < 0.5m and ceq sur for x > 0.5m. this sharp boundary cannot be maintained downstream or y > 0m, because there is transversal diffusion and dispersion causing mixing of the two fl uids when they fl ow down the aquifer. when a parcel of water moves downstream along the y-axis and arrives at the position vy·t = y after time t, the sharp boundary has been widened to a mixed fringe with width wx = 2(d·t)1/2 in the x-direction, where d=dm+vy·dm is, the transverse dispersion coeffi cient resulting from molecular diffusion with coeffi cient dm and transversal mechanical dispersion by fl ow with velocity vy through the pores with diameter d. this mixing produces undersaturation with respect to calcite and consequently dissolution of carbonate rock. the concentration cmix of the fresh mixed solution depends on the degree of mixing m, which can be written as: cmix(m)=m·ceq sur+(1–m)·ceq phr (1) with m= vsur/ (vsur+ vphr), where vphr and vsur are the volumes of phreatic and surface water respectively. due to the renewed aggressivity of the mixed water, its equilibrium concentration with respect to calcite increases by δceq. the equilibrium concentration of such mixed water can be written as ceq mix(m)=cmix(m)+dceq(m) (2) it can be calculated by use of phreeqc (parkhurst & appello, 1999) as a function of m. since the groundwater velocities are so slow, the mixed solution has suffi cient time to come to the new equilibrium, and we can assume that this is true everywhere in the diffusion-mixing zone. fi gu re 2: modelling domain derived from fig. 1. a constant fl ow with velocity vy is injected into the left hand side boundary. for 0 < x < 0.5m the infl owing water stems from the phreatic aquifer, corresponding to a mixing ratio m = 0, whereas the region from 0.5m < x < 1m carries water from the surface, with mixing ratio m = 1. the right hand side boundary is open for the outfl ow. the upper and lower boundaries are regarded as impermeable (see text). a) b) geologia croatica 63/2geologia croatica 132 in the next step we have to fi nd d 2δceq/dm for realistic geochemical scenarios. ground waters in carbonate rocks are calcium-bicarbonate dominated. therefore in a good approximation, for simplicity we assume both waters are pure calcium-bicarbonate waters in the system caco3-co2 –h2o, saturated with respect to calcite and in equilibrium with some low pco2 – value characteristic for the phreatic water, and with a pco2 – value signifi cantly higher for the water entering from the surface. with these conditions, both waters are completely defi ned and the chemistry of solutions mixed from these waters can be calculated by geochemical codes such as phreeqc. we have investigated three different geochemical scenarios. in the fi rst scenario a) we assume pco2 = 10–3 atm for the phreatic water and 10–2 atm for the water from the surface. this is a case dominated by an inorganic chemistry. fig. 3a shows the results of phreeqc at a temperature of 25 °c. it depicts δceq(m) as a function of m. δceq(m) can be fi tted by a quadratic expression. therefore the second derivative becomes a constant d2δceq/dm2 = –0.3 mol/m3. in the second scenario b) we assume a signifi cantly higher pco2-value in the surface water, which may have been caused by organic co2-producing processes in the vadose zone. therefore the pco2 of the surface water is raised to pco2 = 0.1 atm. δceq(m) also shown in figure 3a, is no longer symmetric. in the region between m = 0.4 to m = 0.6 values are about –3 mol/m3 one order of magnitude higher than in scenario a). it is just this region, where ñ → (m)2 exhibits its maximum. as a consequence porosity change is enhanced in scenario b) by one order of magnitude compared to scenario a). this will be discussed later in detail. in scenario c) we assume that the water of the phreatic zone is in equilibrium with the pco2 = 3 10–4 atm of the atmosphere and the surface water now has a pco2 of 0.05 atm. the second derivative has values of –2.17 mol/m3 at m = 0.5. also this scenario exhibits enhanced porosity change compared to scenario a). fig. 3b shows the second derivative for the three scenarios. to calculate the distribution m(x,y) we use the modelling domain in fig. 2. but, we now replace the two concentrations by their mixing ratios, m = 1 for the surface water and m = 0 for the phreatic water. the equation governing mixing m is eq. 5, which we rewrite as (7) to obtain the local distribution of m we create a numerical model using pmwin (chiang & kinzelbach, 2001). this software provides a front-end to modflow (mcdonald & harbaugh, 1988) and mt3dms (zheng & wang, 1999). we use these models to calcula te the distribution of m in our modelling domain (see fig. 2). 3. results we use the parameters φ0 = 0.3, vy = 10–6 m/s and d = 100µm. furthermore we assume a constant hydraulic conductivity in the entire modelling domain. fig. 4 depicts the distri bution of mixing m throughout the domain. as expected, the diffusion-mixing zone widens with distance from the entrance. fi gu re 3: a) renewed solution capacity δceq for surface and phreatic water as a function of the mixing ratio m for three geochemical scenarios. a) (inorganic) pco2 of phreatic water 0.001 atm, pco2 of surface water water 0.01 atm, b) (decay of organic matter). pco2 of phreatic water 0.001 atm, pco2 of surface water water 0.1 atm, c) (decay of organic matter). pco2 of phreatic water 0.0003 atm, pco2 of surface water 0.1 atm. b) second derivatives d 2δceq/dm2 for the three scenarios a), b) and c). fi gu re 4: spatial distribution of the mixing ratio m for a homogeneous aquifer in the modelling domain of fig. 2. the curves give isolines of m. vy = 10–6 m/s. a) b) dreybrodt et al.: evolution of caves in porous limestone by mixing corrosion: a model approach geologia croatica 133 by calculating numerically the partial derivatives ¶m/ ¶x and ¶m/ ¶y and applying eq. 7 one obtains the initial change in porosity dφ/dt/0 year–1. the increasing porosity causes a local positive feedback. from eq. 7 we have (8) and from this (9) using the positive feedback of increasing porosity expressed in eqs. 8 and 9, one can estimate an upper limit of the time t for the change of porosity from its initial value φ0 = 0.3 to a value v0 (t)=1 as t = –φ0·τ·ln (φ0). therefore with φ0 = 0.3 the maximum time t needed to excavate the region bordered by the isoline 1/τ = dφ/dt/0 is about t = 0.36·τ. 3.1. geochemical scenario a: the inorganic case in the following we will fi rst discuss the results for the geochemical scenario a), where the second derivative is constant, because in this case the distribution of porosity change is proportional to (ñ → (m(x,y))2. therefore all fi gures showing dφ/dt/0 also refl ect the local distribution of (ñ → (m(x,y))2. fig. 5a illustrates the spatial distribution of porosity change by a gray scale. furthermore it depicts isolines of dφ/dt/0. from fig. 5 one visualizes that over a maximum time span of 120 000 years, a cave is created, extending to about 3 m in width and 0.2 in height. this is seen from the isoline with 3·10–6 year–1. to excavate a void of about 1m width and 0.1 in height (isoline 1·10–5 year–1), only 38 000 years are needed. these numbers are the upper limits because porosity changes increase inside the region bordered by the isoline. fig. 5b illustrates the distribution of initial change of porosity along transects in the x-direction with y = 0.1, 0.5, 1 and 2.5 m. porosity change decreases with increasing distance from the input in the y-direction, such that evolution of porosity is restricted to a region extending a few metres away from the input in the fl ow direction. in the transverse direction to fl ow along x this region is limited to several tenths of a metre. flow velocities in the floridan aquifer are as low as several 10–7 m/s. therefore in fig. 6 we show the results for a fl ow velocity of 5·10–7m/s, everything else being unchanged in comparison to fig. 5. due to the low fl ow velocities, the region where the diffusion-mixing zone exhibits high gradifi gu re 5: a) spatial distribution of initial porosity change dφ/dt/0. the isolines represent porosity change in year–1 for the geochemical scenario a (inorganic). vy = 10–6 m/s; b) vertical distribution of initial porosity change for the three geochemical scenarios a, b, and c along transects shown in panel a as vertical lines. fi gu re 6: a) spatial distribution of initial porosity change dφ/dt/0. the isolines represent porosity change in year –1 a) the geochemical scenario a (inorganic). vy =5·10–7 m/s; b) vertical distribution of initial porosity change for the three geochemical scenarios a, b, and c along transects shown in panel a as vertical lines. a) a) b) b) geologia croatica 63/2geologia croatica 134 ents and consequently high changes of porosity, becomes smaller as can be seen by the isoline of 3·10–6 year–1. the cavity created in 120 000 years extends only to 1m from the input in the y – direction and has a height of about 0.1m. the distribution of porosity change in the x – direction along the transect in fig. 6b closely resembles that of fig. 5b, but the porosity change is lower in the centre of the diffusion-mixing zone. 3.2. geochemical scenarios b) and c): the organic case the times of cave evolution in the inorganic scenario are too long to explain the existence of isolated caves in florida. these have originated during quaternary sea level changes, where times of constant sea level elevations lasted no longer than 10 000 years. mylroye & mylroye (2007) have suggested that biogenic decay of organic matter caught on the top of the phreatic mound of the surface water increases its co2 concentration. we have taken this into account by increasing the pco2 of the surface waters in the geochemical scenarios b) and c). as can be seen in fig. 3b the second derivatives are higher by almost a factor of ten for m ≈ 0.5. therefore one expects the evolution of caves in time scales of 10 000 years, supporting mylroye’s thesis. we have modelled these organic cases. transects of the evolution of porosity in comparison to the inorganic scenario are illustrated in figs. 5b and 6b. they show that porosity changes are indeed signifi cantly higher for both organic scenarios. due to the asymmetry of the second derivatives the maximum of porosity evolution shifts upwards into the surface water region. these results indicate that caves with dimensions of about 1m width and 0.2 m in height can be created along the border where surface water with higher pco2 encounters the water table of the phreatic base fl ow. this way we obtain blind ending passages of several 10 m to100 m length. these results are in concordance with the height to width ratios observed by florea (2006) in the caves of west central florida. most of them (47%) have ratios of about 0.3, similar to our values of about 0.1. the time needed to create such caves is in the order of 10 000 years. note that our modelling assumes a constant sea level during the entire time of evolution to which the palaeo water table of the phreatic aquifer was tied. it should be noted here that at present in this work we have only modelled initial porosity changes and have just considered the feedback by eqs. 8–11 to estimate an upper limit of the time for cave evolution. future modelling should take into account changes of hydraulic conductivity due to the change in porosity. the corresponding changes in the fl ow pattern by focusing of fl ow lines and the corresponding increase in mixing gradients might enhance porosity change in time. our modelling results show that due to the rise of pco2 – levels by decomposition of organic matter in the water seeping down to the phreatic aquifer signifi cant voids and caves similar to those observed in florida can originate in a time scale of 10 000 years as an upper limit. these are the maximum times of constant sea level stand in the quaternary. for the inorganic scenario, signifi cant changes of porosity from 0.3 to 0.5 arise within time spans of about 10 000 years in regions with dφ/dt/0 = 10–5 year–1. in the organic scenarios, even if the times of constant boundary conditions are too short for the evolution of caves, changes in porosity by about 50 % need time spans of about 1000 years. 4. conclusion when two carbonate waters saturated with respect to calcite, but with different concentrations of calcium meet in an aquifer, they are mixed, and the spatial distribution of the mixing ratio m(x,y) describes the degree of mixing. depending on m an amount dceq(m) is dissolved in the diffusion-mixing zone by mixing corrosion and the porosity of the rock increases. the change dφ/dt in porosity depends critically on the spatial distribution of m(x,y) and on the chemistry of the mixed solution. when the two water bodies meet along a one dimensional border, isolated caves with blind ending passages can develop in the diffusion-mixing zone extending along such boundary lines. as long as these are located in the phreatic zone, fl ow through them is directed transverse to these passages and horizontally along the water table. we have modelled cave evolution for a hydrogeological scenario where surface water with elevated pco2 of 0.1 atm, originating from biogenic decay of organic matter, enters the water table of an unconfi ned aquifer below. the results of these modelling attempts closely resemble caves in west – central florida (florea, 2006; florea et al., 2007). this concept of horizontal transverse speleogenesis could be used in the future to explain the evolution of isolated caves, in other karst areas, such as those described at mt scopus formation (israel) by frumkin & fischhendler (2005). our concept should not be mixed with the concept of hypogenic ascending speleogenesis by klimchouk (2007). in this case, aggressive water ascends from adjacent formations below the cave level through fractures, and fl ow crosses the cave passages vertically. the modelling approach presented here is a fi rst step into gaining an understanding of speleogenesis of isolated caves in porous rock, which are so much different from the caves arising by dissolution of limestone with negligible porosity by aggressive solutions fl owing along fractures from an input to an output. references chiang, w.h. & kinzelbach, w. (2001): 3d-groundwater modeling with pmwin.− springer-verlag, berlin, heidelberg, new york, 397 p. davis, h. (1996): hydrogeologic investigation and simulation of groundwater fl ow in the upper floridan aquifer of north-central florida and southwestern georgia and delineation of contributing areas for selected city of tallahassee, florida, water-supply wells: u.s. geological survey water-resources investigations report, 95−4296. dreybrodt, w. (1988): processes in karst systems.− physics, chemistry, and geology, springer, berlin, 288 p. dreybrodt, w. & gabrovšek, f. (2003): basic processes and mechanisms governing the evolution of karst. / speleogenesis and dreybrodt et al.: evolution of caves in porous limestone by mixing corrosion: a model approach geologia croatica 135 evolution of karst aquifers 1 (1), re-published from: gabrovšek, f. (ed.): evolution of karst: from prekarst to cessation. postojna– ljubljana: zalozba zrc, 115−154. dreybrodt, w. & romanov, d. (2007): time scales in the evolution of solution porosity in porous coastal carbonate aquifers by mixing corrosion in the saltwater – freshwater transition zone.− acta carsologica, 36/1, 25−34. dreybrodt, w., gabrovšek, f. & romanov, d. (2005): processes of speleogenesis: a modeling approach.– karst research institute, zrc sazu, postojna, slovenia. florea, l.j. (2006): architecture of air-fi lled caves within the karst of the brooksville ridge, west-central florida.− journal of cave and karst studies, 68/2, 64–75. florea, l.j., vacher, h.l., donahue, b. & naar, d. (2007): quaternary cave levels in peninsular florida.− quaternary science reviews, 26, 1344−1361. florea, l.j. & vacher, l.h. (2004): cave levels, marine terraces, paleoshorelines, and the water table in peninsular florida.− archives of climate change in karst. karst waters institute special publication, 10. ford, d.c. & williams, p.w. (2007): karst hydrogeology and geomorphology.− john wiley & sons ltd., 562 p. frumkin, a. & fischhendler, i. (2005): morphometry and distribution of isolated caves as a guide for phreatic and confi ned paleohydrological conditions.− geomorphology, 67, 457−471. hanshaw, b.b., back, b. & rubin, m. (1965): radiocarbon determinations for estimating groundwater flow velocities in central florida.−. science, 23, 494–495, doi: 10.1126/sci ence.148.3669. 494. kaufmann, g. (2005): structure and evolution of karst aquifers: a fi nite-element numerical modeling approach.− in: dreybrodt, w., gabrovšek, f. & romanov, d. (eds.): processes of speleogenesis: a modeling approach. karst research institute, zrc sazu, postojna, slovenia, 323−371. klimchouk, a. (2007): hypogene speleogenesis: hydrological and morphogenetic perspective, national cave and karst research institute. special paper no.1. mcdonald, m.c.& harbaugh, a.w. (1988): modflow, a modular three – dimensional fi nite difference ground – water fl ow model.− u. s. geological survey, open – fi le report, 83−875. motz, l.h. (1998): vertical leakage and vertically averaged vertical conductance for karst lakes in florida.− water resources research, 34, 159−167. motz, l.h., sousa, g.d.& annable, m.d. (2001): water budget and vertical conductance for lowry (sand hill) lake in north central florida, usa.− journal of hydrology, 250, 134−148. mylroie, j.e. & carew, j.l. (1990): the fl ank margin model for dissolution cave development in carbonate platforms. earth surface processes and landforms, 15, 413–424. mylroie, j.e. & carew, j.l. (2000): speleogenesis in coastal and oceanic settings.− in: klimchouk, a., ford, d.c., palmer, a. & dreybrodt, w. (eds.): speleogenesis: evolution of karst aquifers. national speleological society, huntsville, 226–233. mylroie, j.e. & carew, j.l. (2003): karst development on carbonate islands. speleogenesis and evolution of karst aquife & harris, p.a. (eds.), 1995. unconformities in carbonate strata – their recognition and the signifi cance of associated porosity, aapg memoir, 63, 55–76. mylroie, j.e. & mylroie, j.r. (2007): development of the carbonate karst model.– journal of cave and karst studies, 69, 59−75. palmer, a.n. (1991): origin and morphology of limestone caves.− geological society of america bulletin, 103/1, 1−21. palmer, a.n. (2007): cave geology.− cave books, 454 p. parkhurst, d.l. & appelo, c.a.j. (1999): user's guide to phreeqc (version 2). a computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations: u.s. geological survey water-resources investigations report 99−4259, 312 p. phillips, o.m. (1991): flow and reactions in permeable rocks.− cambridge university press, new york, 285 p. romanov, d. & dreybrodt, w. (2006): evolution of porosity in the saltwater-freshwater diffusion-mixing zone of coastal carbonate aquifers: an alternative modeling approach.− journal of hydrology, 329, 661−673. werth, c.j., cirpka, o.a. & grathwohl, p. (2005): enhanced mixing and reaction through fl ow focusing in heterogeneous porous media water resour. res., 42, 12, w12414 10.1029/2005wr 004511 zheng, c. & wang, p.p. (1999): mt3dms, a modular three-dimensional multi-species transport model for simulation of advection, dispersion and chemical reactions of contaminants in groundwater systems; documentation and user’s guide, u.s. army engineer research and development center contract report serdp-99-1, vicksburg, ms, 202 p. manuscript received november 24, 2009 revised manuscript accepted march 19, 2010 available online may 31, 2010 geologia croatica 63/2geologia croatica 136 1. introduction due to their lithological and sedimentological characteristics, the geometry and genesis of sedimentary bodies of biocalcarenite with large-scale cross-bedding attract special attention in studies of the neogene sediments on the hill-sides of the slavonian mts. they are characterised by a variety of cross-bedding sets in respect to the thickness and angle of inclined beds, type of cross-bedding within certain sets and dimensions of the sets, as well as to their lateral and vertical relations with or without prominent erosion and redeposition. in spite of the fact that such neogene sediments are widely distributed along the croatian sw margins of the pannonian basin, not much data has been published. shoreline cross-bedded biocalcarenites (middle miocene) in the podvrπko-©njegaviê area, mt. psunj, and their petroleum significance (poæega subdepression eastern croatia) josipa veli∆ , josip ti©ljar , ivan dragi»evi∆ and ivan bla©kovi∆ this is especially true for the interpretation of the depositional systems in which these biocalcarenitic sediments were formed. apart from a short review of the contemporary understanding of such sediments, this paper deals with the structure and interpretation of the cross-bedded biocalcarenites in the podvrπko©njegaviê area on the se slope of mt. psunj (fig. 1) and with their significance (potential) as petroleum and gas reservoir rocks. in the last 25 years, the poæega subdepression and its marginal parts have been explored on several occasions. gravimetric and geoelectrical measurements as explained in the work of kova»evi∆ & mujagi∆ (1975) led to a number of conclusions the depression has a markedly blocky structure; the maximal thickness of neogene and quaternary sediments is at least 2500 m; there is a predominance of fine-grained clastics and faults were determined along the northern and western margin of the valley. in a later paper (milju© & vugrinec, 1997) faults at roughly the same positions are shown in maps and cross-sections. a prognosis for the thickness of the transgressive miocene sediments was given for the first time. for example, 5 kilometres in the direction of the valley from the basement outcrops on its western margin (the location of the podvrπko -©njegaviê cross-bedded biocalcarenite sedimentary bodies), the transgressive miocene sediments reach a thickness of 1000 m. results of a more comprehensive study of the poæega subdepression were published by najdenovski & udjbinac (1980). their set of subsurface maps depict the strike of faults and their throws at various marker horizon levels, the position of a number of anticlines and synclines, as well as the thickness of specific sediment intervals. the poæega subdepression was determined by najdenovski (1988) to be a typical intramontane basin, t e c t o n o g e n e t i c m i c r o t e c t o n o c o n c e n t r e with certain sedimentary phases marked by inverse movements the western part subsided faster during deposition of the miocene sediments, and the eastern part subsided more in the pliocene. in the okuëani-pakrac-novska area on the western slopes of mt. psunj, seven lithofacies were determined within a continuous zone of badenian sediments (blag eol. c roa t. 53/2 281 293 6 figs. zagreb 2000 key words: cross-bedded biocalcarenites, shoreline deposits, subaqueous dune, petroleum and gas reservoir sandstone, synsedimentary tectonics, badenian, poæega subdepression, pannonian basin, eastern croatia. university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, hr-10000 zagreb, croatia. abstract the extensively distributed bioclastic sedimentary bodies in the podvrπko-©njegaviê area, mt. psunj (poæega subdepression, eastern croatia) are mostly composed of fragments of bryozoans, echinoids, lamellibranchs and corallinaceans. apart from this, a relatively compositionally uniform, but granulometrically variable bioclastic detritus occurs, which also contains a smaller proportion (5-30%) of siliciclastic grains of medium to coarse sand, as well as sporadic pebbles up to 60 mm in diameter. these sediments are characterised by remarkably large-scale cross-bedding with erosional surfaces clearly delimiting the sets. they are interpreted as shallow-marine shoreface subaqueous dunes, sand bars and barriers formed on the nearshore mainly shoreface area during the late badenian in a high-energy depositional cycle with strong synsedimentary tectonics. with regard to the petroleum-geological reservoir characteristics, the described middle miocene cross-bedded biocalcarenites are compared with numerous large oil and gas pools globally, and in other localities in croatia on the margins of inselberg massifs between the drava and sava rivers and south of the sava river. 282 geologia croatica 53/2 ©kovi∆ et al., 1982). they range from coarse-grained near-shore and the biohermal and biocalcarenite forereef and back-reef sediments, through slope facies to turbidites. large masses of horizontal and cross-bedded biocalcarenites with 5-40% of siliciclastic grains were described. they were interpreted in terms of bioclastic sands that originated from decomposition of biolithite reefs, and were transported and deposited during cyclic variations in water energy, predominantly waves and tide currents. hydrodynamics controlled the intensity of reef destruction, as well as the transport, sorting and accumulation of detritus in shallow high-energy environments. based on outcrop analysis in the vicinity of the podvrπko village, the cross-bedded bioclastic badenian sediments on the se slopes of mt. psunj, close to the margin of poæega subdepression, were interpreted as submarine fan-delta deposits (bla©kovi∆ et al., 1985). the authors had postulated the basic principles of formation of such a delta and assumed (later found to be correct) that kind of large cross-bedded sedimentary body and other similar ones surely exist at other places on the rim of the poæega subdepression. similar conclusions were reached during the survey for the basic geological map. jami»i∆ et al. (1987) explained that the badenian sediments in the gornji vrhovci area are developed in a delta facies. the studied, nearly 100-mthick section of conglomerates consists of several tens of cross-bedded sets that are 0.5 to 3 metres thick. the conglomerates are composed of well-rounded pebbles fig. 1 location map and geological setting (jami»i∆, 1989; jami»i∆ & brki∆, 1987). of different metamorphic and igneous rocks, as well as of lithothamnium, lamellibranch and echinoid fragments. the badenian sediments in the broader surroundings of podvrπko were also found to be of deltaic origin (jami»i∆ et al., 1989). within almost a hundred metres of the conglomerate sequence, a number of cross-bedded sets were discerned. lower miocene freshwater clastics that were deposited before the badenian cross-bedded biocalcarenites were studied by paveli∆ (1998) at mt. poæeπka gora, not far from the podvrπko locality. he interpreted these freshwater sediments, probably of ottnangian age, to have been formed in two successive sedimentary-tectonic phases an older alluvial and a younger lacustrine phase. the uninterrupted ottnangian-badenian sequence of sediments along the southern margin of the pannonian basin system was described by paveli∆ et al. (1998) in terms of a depositional sequence that can be divided into three parts. the lower part is composed of laminated lacustrine siltstones with sandstone interbeds and of horizontally bedded offshore-shoreface sandstones that contain bioclasts of shallow-marine organisms. the middle and upper part of the sequence is characterised by trough cross-bedded sandstones interlayered with thin-bedded horizontally laminated biocalcarenites (mostly composed of the fragments of corallinaceans, bryozoans, lamellibranchs and echinoids) and by trough cross-bedded conglomerates with erosional contacts between the sets. the authors interpreted these sediments as having been formed by migration of subaquatic 3d-dunes in the upper shoreface environment. the planar cross-bedded sandstones and conglomerates with inclination of sets in the 20-30° range and dipping towards the sea compose the middle part of the succession. they are interpreted in terms of the small-scale foresets of the gilbert-type marine fan-deltas. the top part of the succession is composed of massive marls with biocalcarenite interbeds. these marls are interpreted as the offshore sediments, and biocalcarenites as turbidites ta b intervals of the bouma sequences. in light of the above knowledge on the badenian biocalcarenites our aim was to give more details on their genesis, synsedimentary tectonic influence and petroleum geology significance, bearing in mind the distribution of such deposits and their global importance as reservoir rocks. 2. lithologic composition, structure and geometry of the sedimentary bodies in the podvrπko-©njegaviê area (fig. 1) the miocene (mostly badenian) sediments unconformably and transgressively overlie the crystalline rocks of mt. psunj. the sediments are mostly periclinally positioned and as a rule covered by younger deposits. the cross-bedded biocalcarenite sedimentary bodies in the podvrπko ©njegaviê area have a monotonous lithological composition: sandy biocalcarenites prevail over biocalcirudites. apart from the more or less uniform, but granulometrically very variable bioclastic detritus, they contain a minor amount (5-30%) of siliciclastic particles which have dimensions of mediumto coarse-grained sand, and sporadically pebbles up to 60 mm in size. fragments of reef and fore-reef organisms are most frequently found. there is a marked predominance of more or less rounded and abraded, poorly to well sorted bioclasts of bryozoans, echinoids, ostreids and of corallinacean algae (lithothamnions), and fragments of corals and benthic foraminifers are less abundant. siliciclastic grains and pebbles, mostly of the size of coarse and medium-grained sand (0.2-1.5 mm) and partly gravel-sized (2-60 mm), are mainly composed of the monocrystalline and polycrystalline quartz grains, and fragments of crystalline rocks, feldspars and micas. together with quartz grains, the quartzite fragments and mica-schists prevail over the granitoid, gneiss and phyllite fragments. feldspars are represented by the exceptionally fresh grains of microcline and sodium plagioclases, and micas by the coarse leaves of muscovite and a small fraction of comparatively fresh biotite. the siliciclastic grains are generally poorly rounded, although semi-rounded and rounded grains and pebbles occasionally appear. within certain more lithified sets of cross-bedding, matrix is practically absent and the biocalcarenites are characterised by the grain-support of the bioclasts and siliciclastic grains. the intergranular, intraskeletal and interskeletal pores are filled with a relatively large quantity (in comparison with the total rock volume) of macrocrystalline drusy mosaic calcite cement, and all the echinoid bioclasts are covered by the variously thick layer of syntaxial calcite cement. in these kinds of biocalcarenites, where the detritus is very much washed out, the more prominent or total lithification of the sets of cross-bedding is caused by the three factors: the absence of the micrite and clayey matrix, high level of sorting and comparatively high proportion of the syntaxial and drusy mosaic calcite cement. lithified sets of cross-bedding stand out between the majority of the sets, or parts of sets in most of the sets of cross-bedding, that are poorly lithified or unlithified (figs. 2, 4 and 5). so, there was some primary reason for the development of the cyclically changing character of the clast fabric, i.e. composition of the coarse-grained foresets and fine-grained bottomsets (fig. 4). apart from the poorly sorted bioclasts and variable ratio of siliciclastic grains, the upper parts of the sets of large-scale trough cross-bedding of the biocalcarenites contain a large proportion of fine bioclastic detritus (silt-sized) with a very small amount of finely dispersed clayey matrix. this composition hindered lithification, especially cementation, of this type of biocalcarenite making them very poorly lithified and subjected to erosion (figs. 2, 3 and 4). it is common when grain avalanche is the main transport mechanism on foresets that grain size increases downward. 283veliê, tiπljar, dragiëeviê & blaπkoviê: shoreline cross-bedded biocalcarenites (middle miocene)... 284 geologia croatica 53/2 among the most prominent characteristics of these sediments, and the most important one from the sedimentological point of view, is the well-observable cross-bedding (figs. 2, 3, 4 and 5) with erosional surfaces that clearly delimit certain sets of the large-scale trough cross-bedding (figs. 3, 4 and 5). the sets of cross-bedding are between 60 cm and 3 m thick and have a width in the range of 1.5-15 m (figs. 3, 4 and 5). the sets are thinning upwards. the succession of foresets within one set of crossbedding is characterised by a regular repetition of granulometric composition and of the ratio of fossil and siliciclastic material. the foresets of the cross-bedding have the greatest thickness in cross-sections oriented parallel to direction of transport, where thickness in the 5-30 cm range can be measured and the angle of dip maximally reaches 25-35° in sections perpendicular to transport. following the reduction of thickness, the angle of foresets is reduced until it finally becomes parallel to the position of the bottomsets, if bottomsets are developed (fig. 4). the coarse-grained foresets (biocalcarenite biocalcirudite) indicate tangential or sigmoidal foresets deposited by grain avalanche, and finegrained bottomsets (fig. 4) turbulence deposition of fine grains from cloud instead of grain avalanche. poor cementation of fine-grained bottomset sediment (fig. 4) is due to the granulometric composition of bottomsets (rich in carbonate silt and pelite). the upper margins of the sets of large-scale crossbedding are usually sharply cut and have the character of an eroded surface (figs. 2, 3 and 4). a number of colateral sets are cut by the same erosional surface and fig. 2 sets of cross-beds of variable lithification due to variations in grain size and in sorting of the same biocalcarenite beds. in the middle part of the photo there is a low-angle cross-bedded unit (x) with rapid erosion of the large-scale cross-bedded biocalcarenites. podvrπko, mt. psunj. fig. 3 detail from fig. 2: erosional surface at the top of a largescale cross-bedding biocalcarenite and a low-angle cross-bedded unit (x). 285veliê, tiπljar, dragiëeviê & blaπkoviê: shoreline cross-bedded biocalcarenites (middle miocene)... covered by a 10-70 cm thick layer of low-angle (mostly 3-10°) cross-bedded biocalcarenite (x on the figs. 2 and 3). they are mostly composed of well-sorted bioclasts with 10-15% siliciclastic grains. in the upper part they contain no matrix and are strongly cemented by large quantities of syntaxial rim calcite cement and drusy mosaic calcite cement. this layer has the shape and sedimentological characteristics which used to indicate a high-energy and relatively shallow water environment: at about the level of breaking waves (“outer planar facies” elliot, 1986) or may be in the swash zone. thin layers with low-angle cross-bedding often occur between large-scale cross-bedded foresets in the upper part of biocalcarenite bodies (fig. 2). as deduced from the general direction of dip of the layers with low-angle cross-bedding, the dip of the foresets of some troughs that were transected roughly parallel to direction of transport, the generalised direction of palaeotransport was to the se. this was seawards from the mt. psunj crystalline massif that was land in miocene times. such a general direction of progradation of the cross-bedded sediments is paralleled by the reduction of the dip angle of inclined layers, and by reduction of the thickness of inclined layers within the sets. it is also noted that certain cross bedded layers that cover erosional surfaces of a number of sets, thin in the same direction, and that there is a general change in the granulometric composition of the biocalcarenites. in the proximal parts of sets, the foresets are composed of the more coarse-grained, strongly cemented and clast-supported biocalcarenite that is rich in fossil fragments. fig. 4 typical weathering morphology of the cross-bedded biocalcarenites with lithified coarsegrained foresets and unlithified fine-grained bottomsets podvrπko, mt. psunj. fig. 5 parts of two sets of the largescale cross-bedded biocalcarenites with erosional surface and low-angle cross-bedded biocalcarenite unit (in the centre of figure). 286 geologia croatica 53/2 the distal, mildly inclined layers are composed of the more fine-grained, matrix-rich and matrix-supported, poorly cemented sandy biocalcarenite. with increasing distance from the source area, there is a general increase in the ratio of the fine-grained detritus and matrix in respect to the coarser fossil detritus. finally, the seaward ends of the sedimentary bodies are composed of the clayey-carbonate (marly) detritus, already mixed with the basin sediments. generally, in the direction of dip of the foresets i.e. in direction of transport, with increasing distance from the source area sea-wards, the following characteristic changes are observed: a gradual thinning of the sets and of the foresets, general reduction of the dip angle of the foresets within the sets, the cross-bedding becoming markedly less observable together with lower visibility of the contacts between the sets. 2.1. crystalline basement and sediments beneath the cross-bedded biocalcarenite sedimentary bodies the neogene sedimentary complex of the poæega subdepression that transgressively (unconformably) overlies the crystalline basement (in petroleum-geological papers treated as the basement rocks) is illustrated in the schematic outline of sedimentation during the badenian age (fig. 6). comparison of this schematic outline with the geological setting given in fig. 1, facilitates an explanation for the character of the biocalcarenite basement. in the study area, the basement of the cross-bedded biocalcarenite bodies is mostly composed of clayey-silty-marly sediments that have the characteristics of fine clastic material deposited in a low-energy environment. there are no coarser fragments of crystalline rocks, which is interpreted as a quiet transgression in the karpathian and early badenian. in spite of the fact that corrallinacean-bryozoan biolithite build-ups were not preserved in situ w i t h i n both discussed study areas, the existence of numerous and widely distributed build-ups of this kind and of the fore-reef shoals (ecologically suitable for development of the thick-shelled lamellibranchs, echinoids and corals), is deduced from large quantities of their bioclasts. the fine-grained silty-clayey clastics, rich in pelagic foraminifera, that are laterally equivalent to the bioclastic sedimentary bodies and are biostratigraphically determined as the lower badenian, were deposited in the deeper, undisturbed and clean, definitely marine environment. the following species are the most common: globigerinoides trilobus ( r e u s s ) , g l o b i g e r i n a concinna r e u s s , praeorbulina glomerosa b l o w , orbulina suturalis brönnimann and orbulina bilo bata d’orbigny. such relatively thin sediments (100-150 m in the golobrdac area fig. 1) not only underlie the facies described above, but are also present in a more extensive area on the south-eastern slopes of mt. psunj where they have a variable thickness and comprise the basal member of other badenian lithofacies. the contact between the silty-clayey basal part and the coarse sandy bioclastic facies is transitional, but over very short time-span (considering its thickness) and comprises a general upward-coarsening sequence. 2.2. lateral equivalents of the cross-bedded biocalcarenite sedimentary bodies laterally to the cross-bedded biocalcarenite sedimentary bodies, the silty-clayey basal part of badenian rocks is regionally overlain by several lithofacies characterised by the significant increase of a sandy component. this can either be bioclastic limestone detritus originating from the reefal material that was accumulated in the thicker biocalcarenite layers, or the succession of sand-clay-marl carbonate sequences that have some turbidite characteristics and are dominated by siliciclastic material. as a rule, the cross-bedded biocalcarenite bodies in the studied areas pass laterally into the biocalcarenites with less marked bedding, or into massive biocalcarenites. this contact is transitional and poorly identifiable in the field due to the lack of outcrops. as a result of the periodicity of sedimentation, in the more distal part of depositional area, the prograding cross-bedded sedimentary bodies that are the most distant from the clastic source area, are characterised by a transitional contact between the underlying cross-bedded foreshore-shoreface biocalcarenite bars, barriers, or deltaic lithofacies and the turbidites. this is, for instance, the case between the badenian sediments and sarmatian and lower pannonian deposits on the western slopes of mt. psunj in the okuëani-pakrac-novska area (bla©kovi∆ et al., 1982). another example is within the massive marls with biocalcarenite interbeds ta b i n t e r v a l s of bouma-sequences on the southern slope of mt. papuk (paveli∆ et al., 1998). 2.3. sedimentary cover of the cross-bedded biocalcarenite bodies in spite of the fact that the locations with the best exposures of the cross-bedded biocalcarenite sedimentary bodies do not enable the analysis of the entire vertical lithofacies succession (there are no outcrops of overlying sediments), a number of conclusions can be drawn from the data acquired in the more general area. sets of cross-bedding are gradually reduced in thickness, the dip angle of the foresets is reduced and the grains become smaller. all this, together with the less pronounced textural characteristics and domination of organic carbonate material over the siliciclastic in the apical parts, points to the weaker transport of material from the source area by increase in relative source distance and thus to the diminishing strength of the principal driving force of the periodic sedimentary transport. 287veliê, tiπljar, dragiëeviê & blaπkoviê: shoreline cross-bedded biocalcarenites (middle miocene)... the badenian limestone bryozoan reefs containing various proportions of the corallinaceans, fore-reef lamellibranchs and echinoids take over the role of the main sedimentary source. continuous sedimentation resulted in the cross-bedded biocalcarenite sedimentary bodies being covered by the mostly massive biocalcarenites without clearly observable stratification. 3. depositional model of the cross-bedded biocalcarenite sedimentary bodies the exceptionally large and sporadically well exposed outcrops of the cross-bedded biocalcarenite sedimentary bodies (figs. 2-5), compared with other data sources that will be discussed, enable a generalised interpretation of the depositional system to be made. the principal elements of this depositional system are defined by the lithological and sedimentological characteristics of these bodies, by their geographic setting in respect to the masses of mt. psunj and mt. papuk, as well as by the miocene geological evolution of the area. the composition of the siliciclastic component, especially of the rock fragments, unaltered feldspars and biotite, combined with other data define the sedimentary source areas and the low grade of sedimentary maturity, i.e. that these sediments pertain to the first depositional cycle (of weathering, transport and deposition during the badenian age). the source material for the sediments in podvrπko area was derived from the crystalline rocks of mt. psunj (fig. 1). a large proportion of the organic limestone detritus (mostly of reefal bryozoans but also of corallinaceans and of fore-reef echinoid origin) points to the existence of significant biohermal build-ups and shallow-marine limestone sediments on the margins of the relatively shallow nearshore zone of the badenian marine area (fig. 6). it is impossible to asses how much of the detritus was derived from the lower miocene sediments, although jami»i∆ et al. (1989) mention the lower miocene clastics close to the peak of mt. psunj which may also be the potential source of detritus. the majority of badenian biohermal and organic shallow-marine limestone rocks were formed during the phase of transgression (fig. 6) worldwide uplift of the sea level (late karpatian to the mid badenian relative sea-level rise haq et al., 1987). the maximal redeposition of organic detritus and progradation of bioclastics in high-energy conditions containing various proportions of siliciclastic material derived from the crystalline rocks happened during the relative sea-level fall (late badenian). apart from the eustatic changes, contemporaneous tectonic pulses cannot be ignored. synsedimentary tectonics are characterised by the intermittent reactivation of the marginal faults uplift of the crystalline massifs and relative subsidence of the nearshore and central parts of the sedimentary area (fig. 6). tectonic movements on the marginal faults are referred to by kova»evi∆ & mujagi∆ (1975), najdenovski & udjbinac (1980), jami»i∆ (1983, 1989), najdenovski (1988) and prelogovi∆ et al. (1995, 1998). the dynamics of depositional model are analysed in several phases. the preliminary phase serves to explain deposition of the underlying silty-marly sediments in the environment characterised by the similar bathymetric conditions. in conditions of relative tectonic quiescence, without significant uplift of the mt. psunj crystalline rock masses, but with minor relative rises of the sea-level, there is a reduction in the transport of terrigenous material in the shallow and wide nearshore zone of the sedimentary area. the mechanical and chemical weathering of the crystalline rocks takes place but without significant transport towards the area of deposition. there is also a lack of pronounced development of limestone reefs on the rims of the nearshore zone. hydrodynamic factors influence deposition of the silty-marly material in a wider and deeper basin area without rock fragments or coarser particles in spite of the relatively close source area. the preparatory depositional phase reflects the influence of certain regional changes that happened. these are: the rejuvenation of tectonic movements on the marginal faults (kova»evi∆ & mujagi∆, 1975; jami»i∆, 1983, 1989; najdenovski & udjbinac, 1980; najdenovski, 1988; prelogovi∆ et al., 1995, 1998), uplift of the land massifs and a general trend of the relative rise of sea-level in the basinal part, and relative sea-level fall at the nearshore (fig. 6), and also changes in climatic conditions. the tectonic reactivation uplift of the crystalline masses and a general relative rise of the sea level resulted in the faster mechanical weathering of the crystalline rocks and in the stronger influx of terrigenous material in a wide and morphologically variable coastal zone. the growth and development of bioherms on the reliefed rims of the shallow nearshore zone was favoured by the climatic conditions and a general trend of sea-level rise. in this way the back-reef platform became a shallow concave sedimentary area. the sea-level rise was compensated by the rate of deposition conditioned by the increased influx of detritus and tectonic uplift. in some places this balance resulted in preservation of the same bathymetric conditions. in the high energy nearshore marine environment, where relative sea-level fall occurred, there was strong destruction of reefs and the organic debris becomes further reworked and mixed with the siliciclastic material brought from the land by torrents and fluvial streams. the intrabasinal transport in the basinal part (fig. 6) is reduced in this phase only a small mass of the siliciclastic-bioclastic material that accumulates is distributed in the wider basinal area where it conformably overlies the previously deposited silty-marly sediments. the first phase of deposition of the cross-bedded biocalcarenite sedimentary bodies reflects a relatively short-lasting process triggered by the reactivated tec288 geologia croatica 53/2 tonic pulses due to the uplift of land massifs, and by the change in inclination of the dish-like back-reef platform. this caused the sudden transport and redeposition of large masses of bioclastic detritus and their mixing with the siliciclastic material on foreshore shoreface environments. a sudden accumulation of the large masses of detritus occurs in the foresets of cross-bedded bodies sand bars, barriers, 3d subaqueous dunes and ebb-deltas, partly with the characteristic sigmoidal shape of inclined layers. the fast progradation and grain avalanche or grain fall transport of bioclastic detritus is thereby presumed both for the bioclastic material from the pronounced reefs, fore-reefs and forereef shoals, and also for the siliciclastic detritus from the land. ebb-deltas are formed between the large sand bars or barriers. concurrently, apart from the bioclastic shore-barrier sand bars and subaqueous dunes, the turbidites were deposited on submarine slopes further offshore and in the basinal part (fig. 6). the gradual relative fall of sea-level in the nearshore part and a rapid progradation of the zone of shore-barrier bars with several biocalcarenite ebb-delta bodies between the biocalcarenite bars and barriers, gradually progrades seaward. large organic build ups (bryozoans and corallinacean reefs) were required to produce a large amount of bioclasts during relative sea-level highstand (“highstand shedding”). this is the period, when large quantities of bioclasts are produced and transported from the reef to the nearshore and offshore. the relative quiescence after the tectonic shock in the source area of the siliciclastic material, as well as in the reef and fore-reef fig. 6 schematic outline of sedimentation during the badenian age in transgressive and regressive conditions by different synsedimentary tectonics in a nearshore and basinal part. 289veliê, tiπljar, dragiëeviê & blaπkoviê: shoreline cross-bedded biocalcarenites (middle miocene)... zone and the back-reef platform, followed by the change in hydrodynamic conditions, results in termination of the fast grain avalanche or grain fall transport of the bioclastic and siliciclastic material. in conditions of low sedimentation rates in the shoreface and offshore-transition zone above the storm-weather wave base, and also on the spacious platform, the destruction of the top of cross-bedded sediments and foresets takes place. the high-energy conditions in the shoreface-zone result in formation of the subaqueous dunes. well-sorted detritus is then redeposited without the fine-grained matrix, in the shape of variously thick low-angle cross-bedded units (figs. 2 and 4), which used to indicate high-energy and relatively shallow water at the level of breaking waves (elliot, 1986). in the foreshore-shoreface-offshore environments, the described mechanism of sedimentation, with numerous repetitions of the preparatory and main phases, enabled formation of a wide zone of the cross-bedded biocalcarenite sedimentary bodies of large dimensions. variously located bodies of the cross-bedded biocalcarenites along the margin of mt. psunj were deposited in different nearshore and offshore environments: there are prograding biocalcarenite shore-barrier bars, subaqueous dunes, ebb-deltas and the fluvialor tidal-dominated deltas with trough cross-bedded channel fills or with the mouth sand bars. in the basinal distal part of the depositional area, the badenian biocalcarenites occur as turbidite members, i.e. ta c intervals of the bouma sequences. namely, a part of the biodetritus was transported by gravitational flows along the distributary submarine channels and canyons in the deeper basinal part where it was deposited, together with other detritus as calcarenaceous sandstones or biocalcarenites of ta-c intervals of the bouma sequences within the turbidite fans (e.g. between the badenian sediments and sarmatian and lower pannonian ones on the western slopes of mt. psunj in the okuëani-pakrac-novska area (bla©kovi∆ et al., 1982) and in the oil wells of the oil fields obod, ladislavci and beniëanci east from mt. psunj in the drava depression (ti©ljar, 1993). 4. geometry of the biocalcarenite sedimentary body as a whole the biocalcarenite lithofacies has significant outcrop dimensions. in the podvrπko -©njegaviê area on the se slopes of mt. psunj (fig. 1), the length of the cross-bedded biocalcarenite sedimentary body (measured parallel to the direction of transport that was determined by measuring the foreset dip directions) is in the 1500-2000-metre range. due to dispersed dip directions of the foresets, the fan-shaped sedimentary body is interpreted with the lensoid transversal and clino-form clinostratified longitudinal cross-sections. the vertical dimension of the cross-bedded biocalcarenites on outcrops with eroded surfaces is approximately 40 m. data on the subsurface geological structure of the poæega subdepression (najdenovski & udjbinac, 1980; najdenovski, 1988) were made use of in the reconstruction of the distribution of the biocalcarenite lithofacies in areas covered by the younger sediments. according to previous authors, there are significant faults along the eastern margin of mt. psunj and on the se margin of mt. papuk within the area of both studied locations. the throw of these faults at the tertiary basement level (pt) is 1300 m or 1500-1900 in places, while the miocene sediments in the podvrπko area are supposed to be approximately 1300 m thick. in the nw part of the poæega subdepression, close to the margin of mt. papuk, over 100 m of miocene sediments in supposed. towards the centre of subdepression, the thickness of miocene sediments suddenly reaches 900 m. such a great thickness of miocene sediments along the mentioned faults undoubtedly supports synsedimentary tectonic activity. as a rule, this enables the progradation and development of the sand bar and deltaic depositional systems, which means that a comparatively large longitudinal area of distribution of the described lithofacies within the badenian area of sedimentation can be expected. in this specific case, this means that the biocalcarenite lithofacies at podvrπko and in the similar area of the gornji vrhovci-sokolina creek can maximally reach 5 km in the e-se direction. this is, naturally, a supposition that has to be confirmed by additional surface and subsurface investigations of this area. 5. petroleum-geology potential of the middle miocene shoreline cross-bedded biocalcarenites at a certain stage in the course of exploration for accumulations of fluids water, oil or gas, emphasis is put on the definition of the reservoir rocks. the general knowledge on them resulted from explorations in the field of the geology of oil and gas pools, which has experienced a boom since the thirties. since the late fifties, attention was drawn to the stratigraphic types of traps among which one of the major groups of rocks with adequate porosity and permeability, i.e. with good reservoir properties, is represented by sands or sandstones. it was noted (mackenzie, 1972) that the main factors of reservoir formation within the sandstone stratigraphic traps are either the lateral variation of lithologic composition and/or the breaks of their continuity. the lateral variations of porosity are mostly the direct consequence of depositional environment, and to a lesser extent they were caused by the post-depositional processes of selective dissolution of the fossil debris and less stable mineral grains and of cementation. the aforementioned was, for instance, confirmed by the works of cleveland & molina (1990). within the cretaceous-oligocene pools of the cańo limoń field in columbia, they documented large variations of 290 geologia croatica 53/2 both the architecture of the sandstone sedimentary bodies and of the reservoir quality within the shoreline and sand bar systems. after leblanc (1972), the genesis of sandstones can be observed in the three most typical depositional environments. the second one described comprises transitional environments of clastic sedimentation arranged in order from periphery to the centre of a depositional basin, wherein deltaic models and coastalinterdeltaic models are discerned. cross-bedded biocalcarenites on the slope of mt. psunj should accordingly be put into the coastal-interdeltaic models, for which leblanc (1972) emphasises their importance for hydrocarbon accumulation. namely, similar conclusions were reached by several groups of geologists working for example in the gulf coast region, southwestern louisiana, upper texas coast, georgia, new england, northern dutch, etc. in a trend of described tendencies of exploration for stratigraphic traps, serra (1985) studied the possibilities of identification of depositional environments by the means of well-logs. he managed to differentiate between approximately ten principal environments, among which the most interesting in this case is the shallow (siliciclastic) sea environment characterised by detrital deposits in moderate water depth (10-200 m), or on a nearshore continent under tides, waves, wind, longshore currents, or storms as dominant sediment-moving forces. it is not always easy to distinguish between the shallow siliciclastic and the deltaic environments according to well log responses and characteristics (serra, 1985). examples are shown of composite-log and dipmeter results taken in the powder river basin and in the godavari basin in india. this illustrates that the rocks studied in this paper are the globally important hc reservoirs, and are exclusively treated as such i.e. classified in a separate group. it also deserves to be mentioned that the hydrocarbon-bearing potential of shoreline cross-bedded carbonate rocks was recognised even earlier. levorsen (1956) for instance, stated that the cross-bedding may often be seen, however, on the weathered surfaces of clastic carbonate rocks. the rocks formed in this way are likely to be porous and therefore be good reservoir rocks, and they probably form a larger proportion of the carbonate reservoir rocks than is generally realised. the most detailed classification was made by rittenhouse (1972). it can serve as a guide and will therefore be briefly explained. firstly, all of the stratigraphic traps are classified in the two major groups the ones that are not connected with unconformities and the unconformity-related ones. the first group is of interest here. it is subdivided in two facies traps (i) and diagenetic traps (ii). the facies traps (i) are formed either of current-transported reservoir rocks (a) or of ones that were not current-transported (b). the genesis of reservoir rocks by current transport is possible in seven environments, out of which the fifth one is interesting in this case. this, nondeltaic coastal environment of deposition is likely to be the one in which the badenian cross-bedded biocalcarenites in the podvrπko area were deposited. after many years of exploration through subsurface mapping, well-log interpretation (primarily of the spontaneous potential curve) and the stratigraphic interpretation of the seismic data ©imon (1980) interpreted the depositional environment of the sava group (a large lithostratigraphic unit that encompasses sediments of approximately upper pannonian and pontian age) in the pannonian basin of northern croatia. he applied the model of the so-called “concurrent deposition” of channel sediments and a concept of the so-called “sub-sea (sub-lake) fan”. the discovered outcrops of the middle miocene (badenian) delta and barrier-bar sediments partially corroborate such results, and they justify modern attempts to direct the hc exploration in croatia more firmly to the stratigraphic traps. naturally, this is the case of the relatively more modest, smaller bodies (several hundreds of metres in thickness and a few kilometres in length) as compared to the ones described by ©imon (1980), which is likely to be a consequence of the fact that the genesis of the described cross-bedded sedimentary bodies is connected to the different depositional environment with a probably smaller sedimentary source area. it is characteristic that pikija et al. (1993), while exploring the miocene sediments of the pools of croatia’s biggest gas fields molve and kalinovac (located close to the hungarian border), determined that the six facies units can be defined at depths below 3000 m. the facies c predominates. it is composed of the badenian biolithites and reef and fore-reef biocalcarenites to biocalcrudites, mostly deposited in high-energy environments. the results stated above were achieved by investigations at locations with representative outcrops. several specimens for porosity measurements were taken at podvrπko on the same occasion. the results were more than encouraging, because it was found that the porosity measured parallel to the sedimentary structures is 18.3%, and that perpendicular to the structures was lower as expected 15.14%. in many of the marginal parts of the inselbergs in the drava-sava interfluve, as well as south of the sava river (all in the southern part of the pannonian basin that is in croatia), sediments of the same time-span were determined. they have similar, but less pronounced sedimentological characteristics and different geological and geomorphological characteristics of the sedimentary source area. it is therefore possible to suppose the strike of sequences of differently sized delta and barrier-bar biocalcarenites, mostly based on the palaeogeographic and palaeotectonic reconstruction. the last remark is a justification of the above petroleum-geological text. even more so considering the results like the ones in the paper from pikija et al. (1993). since these sediments have the significantly increased porosity and permeability that, together with 291veliê, tiπljar, dragiëeviê & blaπkoviê: shoreline cross-bedded biocalcarenites (middle miocene)... other characteristics (lateral and vertical lithologic variability, isolation by the basal, lateral and overlying massive fine-grained sediments acting as the seal rocks, structural position and tectonic fabric), favours the formation of traps, it is concluded that the search for new fluid pools should also be targeted at them. the exploration should result in definition of the size, shape and palaeogeographic orientation of these sedimentary bodies and their relations to the neighbouring facies, as well as of their porosity and permeability distribution, firstly at the surface and then subsequently at depth, using geophysical and geochemical methods and finally the drilling. 6. discussion and conclusion sedimentological interpretations of cross-bedded sedimentary bodies often occur in the literature. this is especially true for the one example that would have more or less similarity with the subject of this paper in terms of their architecture, internal organisation and composition. the oligo-miocene cross-bedded calcarenites on the northern island of new zealand, are mostly composed of the bioclasts of bryozoans, echinoids and benthonic foraminifers with minor proportion of the corallinacean bioclasts. these where interpreted in terms of subaqueous dunes by anastas et al. (1997). the prominent, mostly undirectional large-scale cross-stratification was interpreted as a consequence of the migration of subaqueous dunes on the sea-floor at depth of 40-60 m. the authors explain that such dunes were formed by strong tidal currents that flowed parallel to the sea coast and were combined with oceanic currents. each of the defined cross-bedded sets was formed by a differently curved 3d-dune in conditions of very variable water current regime due to the changes in strength of the tidal and sea-currents, as well as of the variations in influx and transport of the bioclastic detritus. the dimensions, architecture and internal organisation of the miocene cross-bedded biocalcarenite sedimentary bodies treated in this paper have many more similarities in the literature in the examples of the siliciclastic cross-bedded sand bodies. out of numerous papers, the following are singled out because the interpretations of depositional environments presented in them could, according to our views, be applied in the interpretation of the formation of the badenian crossbedded biocalcarenites on the hill-sides of the mountains within the pannonian basin. an important characteristic of the tide-dominated deltas, in contrast to the fluvial-dominated ones is that they do not have a pronounced delta-front because the majority of the sediment is accumulated in a very wide area, according to einsele (1992) by the deposition of large masses of the trough cross-bedded sands and sandstones with ripples. such sands are deposited either in the shallow sea of the estuary mouths, or in the neighbouring deeper environment of a wide submarine delta platform. differently from the ones in the fluvialdominated deltas, the sands are here not positioned in the discrete and isolated mouth bars, but are rather repeatedly reworked and redistributed by tidal currents in the elongated bodies positioned perpendicular to the coastline. that is why they form the elongated sub-parallel sand ridges in places between the estuary distribution channels of the river mouths, and in the deeper submarine part of the delta platform. although the tidal-dominated estuarine deltas usually show a weak progradation, the delta complex as a whole gradually advances in a seaward direction. the approximately ten metres thick trough crossbedded sands that cover the pro-delta offshore mud, and are overlain by the planar cross-bedded sands with foresets of a small dip angle, were explained by galloway & hobday (1983) as a consequence of the transport and constant progradation of sands in the foreshore/coastal barrier sand ridges within a wide-spread depositional system of a wave-dominated delta. large masses of the trough cross-bedded sands are interpreted by galloway & hobday (1983) as the tidal sand ridges on the pro-delta platform of a tidaldominated delta. the analysed outcrops in the podvrπko © n j e g a v i ê area (figs. 2-5) are located in the gorge of a creek and along the road that goes roughly perpendicular to the crystalline core of mt. psunj. due to the poor exposure of terrain, especially because of the too small outcrops parallel to the crystalline core, and also because of the influence of the synsedimentary tectonics on depositional system, it remains to be clear which of the depositional models described above could be applied in an explanation of these cross-bedded biocalcarenite sedimentary bodies. considering the relevant data on the composition, sedimentary structures and shape of sedimentary bodies, as well as the very important role played by the synsedimentary tectonics and variations in palaeogeomorphology, our interpretation given above has been little different from the simple application of the one of described depositional models. the cross-bedded biocalcarenites in the podvrπko ©njegaviê area on the se slope of mt. psunj at the margin of poæega subdepression, shown in figs. 2-5, are interpreted as parts of shoreline-shoreface large sand bar bodies, partly 3d subaqueous dunes, characterised by a steeply inclined foreset (20-35°) and rapid progradation, that were preserved from redeposition. between large scale cross-bedded biocalcarenites thick lowangle cross-bedded units variously occur composed of well-sorted detritus without the fine-grained matrix with erosion base (figs. 2 and 4). this indicates highenergy redeposition of sand bodies in relatively shallow water at about the level of breaking waves. in the shoreface zone with the large masses of mostly bioclastic detritus ebb-deltas with seaward inclined foresets were formed between the bars or subaqueous dunes. cross-bedded biocalcarenites with the landward 292 geologia croatica 53/2 inclined foresets were not found in the podvrπko© n j egaviê area. due to the very complicated shoreline and variable morphology of the nearshore, shoreface and offshore area, together with the intermittent synsedimentary tectonic pulses and the consequent frequent changes in the rate of sedimentary influx and rate of sedimentation and in the rate of progradation, there were sudden changes in conditions and environments of sedimentation along the coastline, and especially in direction of the sea. parallel to the predominant accumulation of biodetritus on the back-reef platform, reef and fore-reef shoals and in the shoreface area, submarine fans and/or turbidite fans are formed in the deeper offshore and basinal part. this was partly caused by tectonic uplift of the land area the crystalline massif of mt. psunj and the shallowest parts of biohermal reefs and reef fore-reef shoals that were closest to the coast, but also by the faulting and subsidence of the nearshore and offshore area. in this way, the rapid progradation of bioclasts and a comparatively steep inclination of foresets were preserved with similarities to gilbert-deltas. regarding the petroleum-geological reservoir characteristics, the described sediments are correlated with numerous large oil and gas pools around the world and put in a separate group reservoirs formed by current transport. sediments of the same geologic age and of similar sedimentological characteristics are also found in other places in croatia on the margins of inselberg massifs between the drava and sava rivers and south of sava river. because of the supposed size and contacts with neighbouring facies, it would be wise to direct the future search for the new oil and gas pools to these objects. acknowledgements this work was supported by ministry of science and technology of the republic of croatia through projects no. 195005, no. 195018 and no. 195021. we wish to thank to dr. orsolya sztanó and to dr. davor paveli∆ for critical reading of this contribution. the laboratory measurements of porosity were performed by the ina-naftaplin co., zagreb, and authors appreciate the kind help of jasna tadej, m.sc. in this sense. 7. references anastas, a.s., dalrymple, n.p.j. & nelson, c.s. (1997): cross-stratified calcarenites from new zealand: subaqueous dunes in a cool-water oligomicene seaway.sedimentology, 44, no. 5, 869892. bla©kovi∆, i., ti©ljar, j. & veli∆, j. (1982): litofacijelne znaëajke tortonskih naslaga u podruëju okuëani-pakrac-novska.geol. vjesnik, 35, 71-86. bla©kovi∆, i., dragi»evi∆, i., ti©ljar, j. & veli∆, j. (1985): badenian submarine fan-delta in the mt. psunj (croatia).6th ias european regional meeting. abstracts & poster abstracts, 5l8-552, lleida. cleveland, m.n. & molino, j. (1990): deltaic reservoirs of the cańo limoń field, colombia, south america.in: barwis, j.h., mcpherson, j.g. & studlick, j.r.j. (eds.): sandstone petroleum reservoirs. springer-verlag, new york, berlin, heidelberg, london, paris, tokyo, hong kong, 281-315. einsele., g. (1992): sedimentary basins. evolution, facies and sediment budget.springer-verlag, berlin, 628 p. elliott, t. (1986): clastic shorelines.in: reading, h.g. (ed.): sedimentary environments and facies.blackwell, oxford, 155-188. galloway, w.e. & hobday, d.k. (1983): terrigenous clastic depositional systems applications to petroleum, coal, and uranium exploration. springer, new york, heidelberg, 423 p. haq, b.u., hardenbol, j. & vail, p.r. (1987): chronology of fluctuating sea-level since triassic.science, 235, 1156-1167. jami»i∆, d. (1989): osnovna geoloπka karta sfrj 1:100000. list daruvar, l33-95.geol. zavod, zagreb (1975-1988), sav. geol. zavod, beograd. jami»i∆, d. & brki∆, m. (1987): osnovna geoloπka karta 1:100000. list orahovica l33-96.geol. zavod zagreb (1971-1986), sav. geol. zavod, beograd. jami»i∆, d., brki∆, m., crnko, j. & vragovi∆, m (1987): osnovna geoloπka karta 1:100000. tumaë za list orahovica l33-96. geol. zavod, zagreb (1986), sav. geol. zavod, beograd, 72 p. jami»i∆, d., vragovi∆, m. & mati»ec, d. (1989): osnovna geoloπka karta 1:100000. tumaë za list daruvar l33-95.geol. zavod, zagreb (1988), sav. geol. zavod, beograd, 55 p. kova»evi∆, s. & mujagi∆, s. (1975): geofiziëka ispitivanja poæeπke kotline.nafta, 1, 3-12, zagreb. leblanc, r.j. (1972): geometry of sandstone reservoir bodies. am. assoc. petrol. geol., mem., 18, 155-212, tulsa. levorsen, a.i. (1956): geology of petroleum.w.h. freeman and company, san francisco, vii+ 703 p. mackenzie, d. (1972): primary stratigraphic traps in sandstones.in: king, r.e. (ed.): stratigraphic oil and gas fields-classification, exploration methods, 293veliê, tiπljar, dragiëeviê & blaπkoviê: shoreline cross-bedded biocalcarenites (middle miocene)... and case histories.-am. assoc. petrol. geol., mem., 16, 47-63, tulsa. milju©, p. & vugrinec, j. (1977): neke osnovne crte geoloπke grae sjevernog dijela hrvatske i karakteristike nakupljanja ugljikovodika.nafta, 78, 425-440, zagreb. najdenovski, j. (1988): dubinski geoloπki odnosi i razvitak struktura u tercijarnim sedimentima poæeπke kotline.unpublished phd thesis, university of zagreb, 146 p. najdenovski, j. & udjbinac, æ. (1980): o tektonici, osobito o dubinskim strukturnim odnosima poæeπke kotline s osvrtom na naftoplinonosnost (panonski bazen).nafta, 5, 223-235, zagreb. paveli∆, d. (1998): taloæna evolucija slatkovodnog donjeg i srednjeg miocena sjeverne hrvatske na temelju analize facijesa.unpublished phd thesis, university of zagreb, 149 p. paveli∆, d., mikni∆, m. & sarkoti∆ ©lat, m. (1998): early to middle miocene facies succession in lacustrine and marine environments on the southwestern margin of the pannonian basin system (croatia).geologica carpathica, 49, 433-443. pikija, m., ©iki∆, k., ti©ljar, j. & hrabak, n. (1993): miocene formations of the molve-kalinovac area (north croatia).nafta, 12, 665-671, zagreb. prelogovi∆, e., jami»i∆, d., aljinovi∆, b., veli∆, j., safti∆, b. & draga©, m. (1995): dinamika nastanka struktura juænog dijela panonskog bazena.1. hrvatski geoloπki kongres, opatija 18-21.10.1995., zbornik radova, 2, 481-486, zagreb. prelogovi∆, e., safti∆, b., kuk, v., veli∆, j., draga©, m. & lu»i∆, d. (1998): tectonic activity in the croatian part of the pannonian basin.tectonophysics, 297, 283-293. rittenhouse, g. (1972): stratigraphic-trap classification.in: king, r.e. (ed.): stratigraphic oil and gas fields-classification, exploration methods, and case histories.am. assoc. petrol. geol., mem., 16, 14-28, tulsa. serra, o. (1985): sedimentary environments from wireline logs.schlumberger, 211 p. ©imon, j. (1980): prilog stratigrafiji i taloænom sustavu pjeπëanih rezervoara sava-grupe naslaga mlaeg tercijara u panonskom bazenu sjeverne hrvatske.unpublished phd thesis, university of zagreb, 66 p. ti©ljar, j. (1993): sedimentary bodies and depositional models for the miocene oil-producing areas ladislavci, beniëanci and obod (croatia).nafta, 10, 531-542, zagreb. manuscript received february 18, 2000. revised manuscript accepted november 13, 2000. 294 geologia croatica 53/2 1. introduction lake pannon covered the area of the pannonian basin during the late miocene. because of its wide-range distribution, economic importance and unique, mostly “caspi-brackish” endemic biota, its lacustrine deposits have attracted much scientific attention in the past hundred years. according to the latest stratigraphic division accepted for the area and bioprovince of the western or central paratethys these deposits belong to the pannonthe palaeogeography of lake pannon during deposition of the congeria rhomboidea beds sándor gulyás jr. ian and pontian chronostratigraphic stages (s t evanovi∆ e t a l., 1990; steininger et al., 1990) (fig. 1). palaeogeographic and palaeoecologic studies started with the analysis of superficial and shallow borehole lacustrine deposits in the transdanubian region of hungary at the beginning of the century (h a l a v á t s , 1902; lőrenthey, 1905). from the 1930’s onwards the inner parts of the basin were also studied because of the initiation and development of hydrocarbon prospecting in the areas of the great hungarian plain. the reliability of any palaeogeographic reconstruction largely depends on the accuracy of the applied stratigraphy. the older palaeogeographical reconstructions were only undertaken on small parts of the lake on the basis of lithostratigraphic and biostratigraphic data. these however, as well as the synthetic reconstructions for larger areas were by no means accurate, as the stratigraphic concept and the sedimentological model underlying them were not without certain ambiguities. according to the traditional hungarian model based on lithostratigraphic and biostratigraphic division of the lacustrine deposits, the slow deposition of the suspended load from the water of the lake was responsible for the gradual infilling of the lacustrine basin. based on abrupt changes in the lithology and the fossil record the age of the lower finer-grained, deepwater deposits was determined to be “lower pannonian”, while the age of the upper shallow-water, sandy deposits were defined to be “upper pannonian” (strausz, 1941; széles, 1971) (figs. 1 and 2). thus the palaeogeographic maps based on this model were in fact facies maps. halaváts (in h a l a v á t s, 1892) referred to an acceptable sedimentation model by noticing the following as early as the end of the last century: “the congeria rhomboidea horizon indispensable for the accurate determination of the pontian stage has been described so far only from the southern parts of hungary (austro-hungary). according to data present ed in the collection of the hungarian royal geological institute and from the literature, localities of this hori zon are known only from the krassó-szörény moun tains (muntii semencului transylvania) and the hills surrounding the mecsek mountains and the city of geologia croatica 54/1 15 26 11 figs. zagreb 2001 key words: molluscs (bivalve), index fossil, palaeobiogeography, neogene, late miocene, lake pannon. university of szeged, department of geology and paleontology, egyetem u. 2-6, h-6720 szeged, hungary. e-mail: sanyi@geo.u-szeged.hu, gubanc@yahoo.com abstract lake pannon covered the area of the pannonian basin during the late miocene. according to the seismic profiles, prograding deltas from the nw and ne resulted in the s-se migration of the northern palaeoshoreline and the gradual aggradation of the lacustrine basin. the molluscan fauna living in the lake underwent a very rapid evolution. for the younger species, the possibilities of spreading became more and more restricted due to the gradual shoaling of the lake. the bivalve species congeria rhomboidea m. hörnes o c c u r s widely in the upper pannonian (pontian sensu stevanoviê) deposits of hungary and the neighbouring countries. its evolution is relatively well understood. according to magnetostratigraphic data this species appeared in the lake 8.5 mya. according to the maximal geographical distributions of c. rhomboidea and its ancestor congeria praerhom b o i d e a st e v a n o v i∆ occurring in sublittoral clay and silt along with the representatives of prosodacnomya coming from littoral and lagoon deposits of the same age the estimated water coverage was around 75,000 km2 at the time of first emergence of c. rhomboidea in the lake. in the north the distribution of c. praerhomboidea is strictly restricted to the north of that of c. rhomboidea, its descendent, implying a clear s-se trend in the migration of the lake’s northern palaeoshoreline. distributions of the littoral p r o s o d a c n o m y a s in relation to the sublittoral c. rhomboidea of the same age display a similar pattern. meanwhile the western and southern palaeoshorelines underwent only minor fluctuations. 16 geologia croatica 54/1 zagreb. this horizon is totally missing in other parts of the country.” since the younger pontian deposits are restricted to the southern parts of former hungary, the lake must have covered only this part of the country and not the whole pannonian basin during the pontian as the traditional model assumed. however, the recognition of the importance of delta sedimentation in the south-eastern part of the great hungarian plain only brought changes in the traditional sedimentological, stratigraphical and palaeogeographical thinking in the 1970’s (mucsi & révész, 1975; magyar & révész, 1976; révész, 1980; gajdos et al., 1983; bérczi & phillips, 1985). the geometry of progradational delta bodies with the particular facies and subfacies could be clearly identified on the seismic profiles from the inner basin areas (pogácsás, 1984; pogácsás & révész, 1987; mattick et al., 1988; juhász, 1991) (figs. 3 and 4). according to the earlier models the abrupt vertical changes in the fossil record and the lithology of the deposits define horizontal chronohorizons ( s t r a u s z , 1971; barnabás & strausz, 1991; széles, 1962, 1971). however, seismic research has shown that the isochronous surfaces are inclined towards the center of the basin (fig. 2), intersecting the horizons marked by boundaries of the bioand lithofacies (szalay & szentgyörgyi, 1979; pogácsás & révész, 1987; horváth & pogácsás, 1988; pogácsás et al., 1988, 1990). in the past few decades the hungarian magnetostratigraphic research has undergone significant development (rónay & szemethy, 1979; cooke et al. , 1979; elston et al., 1990), and today a large number of data are readily available for purposes of integrated r e s e a r c h (balogh & rakovits, 1976; balogh & jámbor, 1987; balázs & nusszer, 1987). the application of these data onto the seismic profiles shows that lake pannon formations are diachronous fig. 1 chronostratigraphic chart for the areas of the central and eastern paratethys (after s t e ininger et al., 1990). (pogácsás et al., 1988, 1989, 1990; vakarcs e t al., 1994). korpásné hódi (in korpasné hódi et al., 1992) was the first to analyze correlations between the newly defined lithofacies and the occurring biofacies for the area of the danube-tisza interfluve. juhász & magyar (1992) extended this type of study to the tiszántúl area, and suggest that it is possible to characterize certain depositional and deltaic environments by given molluscan assemblages marked by dominant, wellidentifiable species (fig. 5). in this way the biostratigraphic horizons were distinguishable from the biofacies existing in the lake. it also facilitated the chronostratigraphic division of lacustrine deposits in a certain environment or facies by means of analysis of evolutionary lineages of molluscan species (magyar et al., 1999; see fig. 6). with the help of these research results it became more and more apparent, that despite the frequent fluctuations in the water level, the infilling of the basin was mainly a uni-directional process. prograding deltas from the margins resulted in an approximately southsoutheast migration of the northern shorelines, and therefore a gradual southward migration of certain facies or depositional environments. as individual environments can be characterized by given molluscan assemblages, the geographical distribution of some molluscan species found in these environments will give a more or less accurate view of the changes in the lake’s extension through time. as with the gradual s17gulyás: the palaeogeography of lake pannon... fig. 2 the sedimentation models for lake pannon (gulyás, 1998). deep-water deposits are marked with black and dark grey, while the shallow-water deposits with light grey and white. the differences in the hue indicate changes in the ages of these deposits (lighter ones are younger). it is clearly observable that the isochronous surfaces marking the changes in the surface with time are inclining towards the center of the basin (2 delta progradational model). in contrast with the traditional model (1), according to which the abrupt changes in the fossil record and the lithological features mark chronohorizons this type of aggradation results in a gradual movement of the facies from the margins towards the center of the basin (2). fig. 3 general configuration of seismic sequences and supersequences in the pannonian basin of hungary (after mattick et al., 1988). 18 geologia croatica 54/1 se shoaling of the lake and the migration of the facies, the younger forms of the molluscan species were also restricted to the southern areas of the lacustrine basin. 2. materials and method palaeogeographic maps based on the new sedimentary model have been based only on magnetostratigraphic and seismic data so far, and only for the area of presentday hungary ( po g á c s á s et al., 1993; vakarcs e t al., 1994). the aim of this study was to map the palaeoshoreline of lake pannon for a given moment as accurately as possible using palaeobiogeographic data, and to test the underlying new sedimentary model for the basin. the bivalve species congeria rhomboidea m . h ö r n e s occurs widely in the upper pannonian (pontian sensu stevanovi∆) deposits both in hungary and in the neighbouring countries of croatia, bosniaherzegovina, serbia and romania as well, which makes it suitable for such investigation (fig. 8). halaváts (1892) acknowledged its primary function for age determination when in his own words he “nominated this well-traceable geological horizon after one of its permanently occuring molluscan forms c o n geria rhomboidea h o r i z o n ” . he placed the age of the horizon into the upper parts of the then accepted upper pontian stage. the first illustrated description of the bivalve species congeria rhomboidea m. hörnes was published in a work entitled “die fossilen mollusken der fig. 4 idealized view of prograding delta sedimentation and the disri bution of sedimentary environments from the se part of the pannonian basin (after b é r c z i & phillips, 1985). fig. 5 characteristic molluscan assemblages marked by dominant species in relation to depositional environments (after juhász & magyar, 1992). note the assemblages marked by congeria rhomboidea m . hörnes and prosodacnomya. 19gulyás: the palaeogeography of lake pannon... tertiaeren becken von wien ii” by m. hörnes (1855). the type locality of this species is árpád (today nagyárpád, a part of the city of pécs) in hungary. it also appears outside the pannonian basin ( a n d r usov, 1897, 1909; hoernes, 1901; wenz, 1942). several theories concerning the origin and the evolutionary lineage of this species have come to light since the second half of the 19th century. most authors were looking for relative forms of this species outside the pannonian basin (andrusov, 1897, 1909; hoernes, 1901; wenz, 1942). stevanoviê was the first to point to a very important factor in the palaeogeography of lake pannon and the paratethys to underlie his phylogenetic concept of congeria rhomboidea m. hörnes (stevanovi∆, 1961, 1978). the pannonian basin evolved during the miocene period. the late miocene belongs to the post-rift phase of basin evolution accompanied by isostatic thermal subsidence due to the thinning and cooling of the lithosphere following the rifting process (k á z m é r, 1990; r o y d e n et al., 1983). during the miocene, connection of the central paratethys with the mediterranean and the indo-pacific ocean was repeatedly opened and closed (rögl & steininger, 1983). the final isolation of the central paratethys commenced in the beginning of the late miocene (steininger et al., 1988). the attic phase of the alpine orogeny in the southern carpathian mountains isolated the water masses covering the pannonian basin from the rest of parathetys from as early as the bessarabian until the beginning of the pontian (13.5-8.5 my), i.e. during the whole pannonian. in the sarmatian this resulted in the creation of miohaline, “brackish” and later on in the pannonian and pontian oligohaline, “caspi-brackish” conditions in the lake. these factors induced the evolution of an endemic molluscan biota bearing unique features. during the early pontian, the connection between the pannonian and dacian basins was restored by means of a waterway formed near the present iron gate: the –erdap or porta ferra strait. across this strait the eurytropic species, which had evolved in the pannonian basin could have migrated eastward into the dacian-euxinic basins. consequently, this species emerged and developed in the pannonian basin and migrated eastward following the restoration of the connections of waterways at a later stage (stevanovi∆, 1961, 1978). the evolution of congeria rhomboidea m. hörn e s is now relatively well-understood. the gradual evolution of congeria rhomboidea m. hörnes f r o m congeria zsigmondyi and a relation with c o n g e r i a p a r t s c h i seems to be well-traceable in the pannonian basin through a number of transitional forms with gradual changes in the shell morphology. from the bivalve species congeria zsigmondyi or a certain type of it (“semiptera”) a strongly convex form with a high shell develops (“praerhomboidea”). then on this form a strong second rib appears (“dubocaensis”), and finally the size of the shell increases (“rhomboidea”) reaching an extreme rate in the final stage of development (“dilatata”) (fig. 7). this gradual change in the shell’s morphology occurs in such a way that there is an extraordinary variety at all levels, so the names represent only certain stages of the evolution. because congeria rhomboidea fig. 6 integrated correlation chart for the lake pannon deposits (after magyar et al., 1999). note that according to the chart the base of the pontian (8.5 mya) is 1-1.5 my. older in the area of lake pannon than in the eastern parathetys. 20 geologia croatica 54/1 m. hörnes exhibits an almost continuous development with hardly distinguishable stages or forms, it is very hard to define the area of its distribution in the lake without knowing how to define the species itself. in this study the form “dubocaensis” is considered to be the very first representative of the species conge ria rhomboidea m. hörnes on the basis of the morphological feature noticed even by lőr e n t h e y (1905) while he was tracing the lineage between c. tri angularis and c. rhomboidea; i.e. the appearance of the second strong rib on the shell to define the species. according to magnetostratigraphic data this bivalve species appeared in the lake approximately 8.5 million years ago (fig. 6). thus its geographical distribution will give us a more or less accurate view about the extension of the lake at this time. a distributional database has been set up from 77 pieces of literature dealing with the pannonian and the pontian. additional data comes from collections at the university of szeged (jate), university of budapest (elte), the hungarian geological institute and the university of debrecen (klte) as well as from the hungarian oil and gas company (mol rt.) (see gulyás, 1998 for details). data had been applied to maps with a scale of 1:600,000, which were reduced afterwards. the geographical distributions of the bivalve species congeria praerhomboidea s t e v a n o v i ∆ and the representatives of the prosodacnomya genera have also been applied onto maps as a complementary and verificatory check, as congeria praerhomboidea s t e v an o v i ∆ is the direct ancestor of congeria rhomboidea m. hörnes. according to the delta progradation model the geographical distribution of this species was expected to be restricted northward of that of c o n g e r i a r h o m b o i d e a m. hörnes. congeria rhomboidea m . h ö r n e s comes primarily from sublittoral deposits clay and silt. thus its distribution will mark the borderline of the sublittoral facies in the lake. in addition the distribution of the representatives of the p r o s o d a c n o m y a genus of the same age coming from littoral deposits will show the incidence of the littoral facies and the gradually freshening lagoons at the same time. fig. 7 the evolutionary lineage of con geria rhomboidea m. hörnes (after stevanovi∆, 1978). 21gulyás: the palaeogeography of lake pannon... 3. results and discussion the constructed palaeobiogeographic map (fig. 8) displays the geographical distributions of congeria rhom b o i d e a m. hörnes and congeria praerhomboidea stevanovi∆ with 192 data points as well as the distribution of localities with representatives of the proso dacnomya genus (310 data points). the larger signs indicate general localities like “the northern slope of majevica mt.” for example. the scarcity of dots on the map in certain areas is due to lack of information because of an insufficient number of boreholes in the area, or the lack of a continuous data record on sublittoral facies deposits, rather than real rarity of the species. conversely, in other areas where many dots are displayed on the map, this does not necessarily imply that more animals must have existed. rather these dots indicate the distribution of localities with surface outcrops, where there is easy access to these fossil-bearing layers. thus lots of data can be found in these areas. the created palaeobiogeographic map records the outcome of complex processes, which had been going on for millions of years in the lake, and do not represent one single moment in the lake’s history. as the northern shoreline migrated to the s-se with the continuos shoaling of the lake, the littoral and sublittoral facies shifted with the passage of time. consequently, for example the specimen of the prosodacnomya g e n u s found at lake balaton might be even millions of years older than the one from battonya, south-east hungary. in order to draw the boundaries of a given facies marked by the geographical distributions of specimens of congeria rhomboidea m. hörnes or the p r o s o d a c n o m y a genus, the maximal area of their distribution had to be considered by taking into account their marginal occurrences. these will more or less accurately give the boundary of the facies at that time, when this species or genus first appeared in the lake. maps (figs. 9 and 10) were created by considering the maximal areas of distribution for the species conge ria rhomboidea m. hörnes, congeria praerhombo i d e a s t e v a n o v i ∆ and the genus p r o s o d a c n o m y a . these will represent the boundaries of the sublittoral facies marked by congeria rhomboidea , and the littoral facies marked by p r o s o d a c n o m y a at the time the bivalve species congeria rhomboidea m. h ö r n e s first emerged in the lake 8.5-8.6 mya (fig. 6). with fig. 8 the geographical distributions of congeria rhomboidea m. hörnes, congeria praerhomboidea stevanovi∆ and prosodacnomya in the pannonian basin. 22 geologia croatica 54/1 the combinations of these two maps a new palaeogeographic map has been set up with the palaeoshorelines and the roughly estimated boundaries of the two facies in the lake for a given moment (fig. 11). on the basis of data presented on the map a water coverage of roughly 75,000 km2 has been calculated. the path of the lake’s northern shoreline seems to correspond to the line of the 8.2 million year chronoboundary on the map prepared by vakarcs et al. (1994) on the basis of seismic and magnetostratigraphic data. therefore the results of the two methods seem to correspond well, underlying the accuracy of the new delta progradational model. however, the accuracy of the age determination of vakarcs et al. (1994) on their map remain questionable (8.2 mya vs. 8.5 mya). the littoral and lagoonal zones marked by the p r o s o d a c n o m y a are mainly restricted to the northern areas of the lake situated roughly north of the line of hrvatsko zagorje (northern croatia) mecsek mts. (southwest-hungary) paks (on the bank of the danube in south-hungary) egyek (north-eastern hungary) (fig. 11). at the same time in the southern slovenian, croatian, bosnian and serbian parts sublittoral and deepwater environments existed in the lake. in some parts in the centre of the lake and on the south-eastern and south-western marginal areas congeria rhomboidea m . h ö r n e s occurs together with p r o s o d a c n o m y a in the localities of beoëin, serbia (stevanovi∆ et al., 1990), an area between the rivers of sava and majevica, northern bosnia (stevanovi∆ et al., 1990), hrvatsko zagorje, croatia (basch & æagar-saka», 1992) (figs. 9 and 10). congeria rhomboidea m. hörn e s appears in a lower position in sublittoral deposits in the sequences, while the representatives of p r o s o dacnomya occur in the overlying younger littoral deposits. similarly in the southern areas posavo-tamnava, kolubara basin, mislodjin, bodarevac, buëje and beoëin, southern serbia (s t e v a n o v i ∆, 1951; s t e v anovi∆ et al., 1990) the older congeria praerhombo idea s t e v a n o v i ∆ and the younger congeria rhom boidea m. hörnes occur in the same localities, but in different stratigraphic levels (figs. 8 and 9). these imply that there were no significant and permanent changes in the position of the shoreline in these southfig. 9 maximum areas of distribution for congeria rhomboidea m. hörnes and congeria praerhomboidea stevanovi∆. note that on the northern part of the pannonian basin the distribution of congeria praerhomboidea stevanovi∆ is restricted to the north of the maximum distribution area of congeria rhomboidea m. hörnes, indicating a continuous unidirectional s-se migration of the palaeoshoreline there. meanwhile on the southern part the two areas tend to overlap at some places indicating only minor fluctuations in the position of the shoreline. 23gulyás: the palaeogeography of lake pannon... ern areas. only minor fluctuations can be observed, and the shoreline seems to have always returned to its original position. on the northern, eastern and western margins of the lake however, the fact that the littoral representatives of p r o s o d a c n o m y a and the older c o n g e r i a p r a e r h o m b o i d e a are restricted strictly north of the area of distribution of congeria rhomboidea m. hörnes implies a steady, gradual migration of the shoreline towards the s-se. the collective appearance of conge ria rhomboidea m. hörnes and congeria praerhom b o i d e a s t e v a n o v i ∆ in some areas, e.g. táska, m e zőcsokonya, kőbánya, nyárád hungary (fig. 8), might represent transitional forms or possibly be wrong determinations, e.g. for nyárád (m a g y a r, pers. comm.). the water coverage assumed by the presence of littoral p r o s o d a c n o m y a s in the alluvial plain areas near sopron, and the kisalföld, northwestern hungary are highly questionable (fig. 10 dotted line area), and this region was not considered to be a part of the lake’s area on the final map (fig. 11). fossils coming from these areas are very hard to determine due to poor preservation, and the majority of them are lost. specimens collected by istván vitális can be found in the hungarian natural history museum, though the single p r o s o d a c n o m y a from sopron is missing. there are three major ways of interpreting these data. first it could be assumed that all the fossil descriptions are incorrect, so there were no p r o s o d a c n o m y a s existing in this area. alternately, the lake managed to occupy the alluvial plain area of the kisalföld for a very short time, so it seems to be acceptable to have some localities with prosodacnomya there. or perhaps the p r o s o d a c n o m y a was capable of adapting to fresh-water alluvial conditions, so its areal distribution did not correspond to the changes in the lake’s water coverage. further investigation is required to clarify this problem. 4. conclusion results of this palaeobiogeographic study seem to corroborate sedimentation hypotheses based on seismic, magnetostratigraphic and sedimentological data for lake pannon, implying a clear s-se migration of the northern palaeoshorelines and depositional environments. this indicates two major applications of palaeontologic and palaeobiogeographic methods. first, the utilization of an integrated multidisciplinary approach, embedding palaeontological data, gives more reliable fig. 10 maximum area of distribution of the p r o s o d a c n o m y a genus. dotted line indicates uncertainty in the water coverage for the area of kisalfld. 24 geologia croatica 54/1 and accurate results. it also seems to be the only relevant tool in settling the controversies surrounding the stratigraphic subdivison and correlation of lake pannon deposits. secondly, the majority of petroleum displays are connected to certain depositional environments. studies such as this may help petroleum exploration by tracing the migration and geographic distribution of depositional environments significant from the point of reservoir and source potential through time in a basin on a purely palaeontological, palaeoecological basis. acknowledgements the author wishes to express his acknowledgements to the following persons: dr. miklós szónoky at the department of geology and palaeontology at jate university of szeged; colleagues at geologia croatica (zagreb) for making this publication possible, especially to dr. igor vlahoviê and mr. oto basch for their help in the identification of croatian localities; dr. pál sümeghy and dr. miklós kozák (klte), dr. andrás galácz (elte) and dr. pál müller and dr. lászló kordos (máfi) for giving access to the palaeontological collections. thanks to the colleagues of the palaeobiology and palaeontology group of the department of geology and geophysics at the university of wisconsin, madison, for their help in reviewing and commenting on the manuscript. finally to dr. imre magyar (mol rt.) for initiating and fully supporting this work. this work has been partly supported by nsf grant ear 9706230 and national science research foundation (otka) grant t/029342. 5. references andrusov, n.i. (1897): iszkopajemüje i zsivuscsije dressenidae evrazii.otd. geol. i min. esestv. tr. spb. ops., 25, 100, st. petersburg. andrusov, n.i. (1909): kriticseszkie zametki o ruszkom neogene 2.: gorizont sz c. subrhomboidea v kamüsvurunszkom profile obsz jesztyesztrojszp.otd. geol. i min. esestv. tr. spb. ops., 2, 155, kiev. balázs, e. & nusszer, a. (1987): magyarország medenceterületeinek kunsági (pannóniai s. str.) emeletbeli vulkanizmusa.a magyar állami földtani intézet évkönyve, 69, 95-113, budapest. fig. 11 the palaeogeographic view of lake pannon 8.5 mya based on palaeobiogeographic data. 25gulyás: the palaeogeography of lake pannon... balogh, k. & jámbor, á. (1987): a magyarországi kunsági (pannóniai s. str.) emeletbeli képzõdmények idõbeli helyzetének meghatározása.a magyar állami földtani intézet évkönyve 69, 27-36, budapest. balogh, k. & rakovits, z. (1976): ék-magyarország néhány miocén vulkanitjának k-ar kora.a magyar állami földtani intézet évi jelentése az 1974. évrõl, 471-476, budapest. barnabás, k. & strausz, l. (1991): a délnyugat-dunántúli pannónikum földtani közlöny, 119,191-306, budapest. basch, o. & æagar-saka», a. (1992): dreissenidae (mollusca, lamellibranchiata) pontskog kata u hrvatskoj.acta geol., 22, 1-96, zagreb. bérczi, i. & phillips, r.l. (1985): processes and depositional environments within neogene deltaic-lacustrine sediments, pannonian basin, southeastern hungary.geophysical transactions, 31, 71-87. cooke, h.b.s., hall, j.m. & rónay, a. (1979): palaeomagnetic, sedimentary and climatic records from boreholes at dévaványa et vésztõ, hungary.acta geologica hungarica, 22, 89-109, budapest. elston, d.p., lantos, m. & hámor, t. (1990): az alföld pannóniai (s.l.) képzõdményeinek magnetosztratigráfiája.a magyar állami földtani intézet évi jelentése az 1988. évrõl, 109-134, budapest. gajdos, i., papp, s., somfai, a. & völgyi, l. ( 1 9 8 3 ) : az alföldi pannóniai (s.l.) képzõdmények litosztratigráfiai egységei.magyar állami földtani intézet , 70, budapest. gulyás, s. (1998): a pannon-tó õsföldrajzi képe a c o n g e r i a r h o m b o i d e á s rétegek lerakódása idején.unpublished m.sc. thesis, university of szeged, 130 p., szeged. halaváts, gy. ( 1 8 9 2 ) : õslénytani adatok délmagyarország neogén korú üledékei faunájának ismeretéhez. vi. a királykegyei pontusi korú fauna.a magyar királyi földtani intézet évkönyve, 10, 25-41, budapest. halaváts, gy. (1902): a balatonmelléki pontusi korú rétegek faunája.in: lőrenthey, i. (ed.): a balaton tudományos tanulmányozásának eredményei 1/1 õslénytani függelék 4/2. 1-74, budapest. hoernes, r. (1901): congeria oppenheimi und hilberi.sitz. d. math.-nat. kl. d. k. akad. d. wiss., bd.110.a.i., 228, wien. horváth, f. & pogácsás, gy. ( 1 9 8 8 ) : contribution of seismic reflection data to chronostratigraphy of the pannonian basin.in royden, l.h. & horváth, f. (eds.): the pannonian basin. a study in basin evolution. aapg memoir, 45, 97-105, tulsa, budapest. hörnes, m. ( 1 8 5 5 ) : die fossilen mollusken der tertiaeren becken von wien ii.th. -abh. d. k. k. g. r.-a., bd. 4, 364-365, wien. juhász, gy. (1991): lithostratigraphical and sedimentological framework of the pannonian (s.l.) sedimentary sequence in the hungarian plain (alföld), eastern hungary.acta geologica hungarica, 34, 53-72, budapest. juhász, gy. & magyar, i. (1992): a pannóniai s.l. lithofáciesek és molluszka-biofáciesek jellemzése és korrelációja az alföldön.földtani közlöny, 122/2-4,167-194, budapest. kázmér, m. (1990): birth, life and death of the pannonian lake.palaeogeography, palaeoclimatology, palaeoecology, 79, 171-188, amsterdam. korpasné hódi, m., pogácsás, gy. & simon, e. (1992): palaeogeographic outlines of the pannonian s.l. of the southern danube-tisza interfluve.acta geologica hungarica, 35, 145-163. lőrenthey, e. ( 1 9 0 2 ) : die pannonische fauna von budapest.palaeontographica, 48, 137-295. lőrenthey, i. (1905): adatok a balaton melléki pannóniai korú rétegek faunájához és stratigráfiai helyzetéhez.in: lőrenthey, i. (ed.): a balaton tudományos tanulmányozásának eredményei 1/1 õslénytani függelék, 4/3, 1-193, budapest. magyar, i., geary, d., sütõ-szentay, m., lantos, m. & müller, p. (1999): integrated bio-, magneto and chronostratigraphic correlations of the late miocene lake pannon deposits.acta geologica hungarica, 42/1, 5-31. magyar, l. & révész, i. (1976): data on the classification of pannonian sediments of the algyõ area.acta mineralogica petrographica, 22, 267-283, szeged. mattick, r.e., phillips, r.l. & rumpler, j. ( 1 9 8 8 ) : seismic stratigraphy and depositional framework of sedimentary rocks in the pannonian basin in southeastern h u n g a r y . i n : royden, l.h. & horváth, f. ( e d s . ) : the pannonian basin. a study in basin evolution. aapg memoir, 45 , 117-145, tulsa, budapest. mucsi, m. & révész, i. ( 1 9 7 5 ) : neogene evolution of the southern part of the great hungarian plain on the basis of sedimentological investigations.acta mineralogica petrographica, 22, 29-49, szeged. pogácsás, gy. (1984): results of seismic stratigraphy in hungary.acta geologica hungarica, 27, 91-108. pogácsás, gy. & révész, i. (1987): seismic stratigraphic and sedimentological analysis of neogene delta features in the pannonian basin.a magyar állami földtani intézet évkönyve, 70, 267-273, budapest. pogácsás, gy., lakatos, l., ujszászi, k., vakarcs, g., várkonyi, l., várnai, p. & révész, i . (1988): seismic facies, electro-facies and neogene sequence chronology of the pannonian basin.acta geologica hungarica, 31, 175-207. pogácsás, gy., jámbor, á., mattick, r.e., elston, d.p., hámor, t., lakatos, l., lantos, m., simon, e., vakarcs, g., várkonyi, l. & várnai, p. ( 1 9 8 9 ) : a nagyalföldi neogén képzõdmények kronosztratigráfiai viszonyai szeizmikus és palaeomágneses adatok összevetése alapján.magyar geofizika, 30, 41-62, budapest. pogácsás, gy., müller, p. & magyar, i. (1990): seismo and biostratigraphy of the late neogene deposits in hungary.9th congress of regional committee on mediterranean neogene stratigraphy, abstracts, 271-272, budapest. pogácsás, gy., müller, p. & magyar, i. (1993): the role of seismic stratigraphy in understanding biological 26 geologia croatica 54/1 evolution in the pannonian lake (se europe, late miocene).geol. croat., 46/1,63-69. révész, i. ( 1 9 8 0 ) : az algyõ-2 telep földtani felépítése, üledékföldtani heterogenitása és õsföldrajzi viszonyai.földtani közlöny, 110, 512-539, budapest. rónay, a. & szemethy, a. ( 1 9 7 9 ) : az alföld-kutatás újabb eredményei. palaeomágneses vizsgálatok laza üledékeken.a magyar állami földtani intézet évi jelentése az 1977. évrõl, 67-84, budapest. royden, l., horváth, f., nagymarosi, a. & stegena, l (1983): evolution of the pannonian basin system. 2. subsidence and thermal history.tectonics, 2, 91137. rögl, f. & steininger, f.f. (1983): vom zerfall der tethys zu mediterran und paratethys. die neogene palaeogeographie und palinspatik des zirkum-mediterranen raumes.ann. naturhist. mus. wien, 85, 135-163, wien. steininger, f.f., müller, c. & rögl, f. (1988): correlation of central paratethys, eastern paratethys and mediterranean neogene stages.i n : royden, l.h. & horváth, f. (eds.): the pannonian basin. a study in basin evolution. aapg memoir, 45, 79-87, tulsa, budapest. steininger, f.f, bernor, r.l. & fahlsbusch, v. (1990): european neogene marine/continental chronologic correlations.in: lindsay, e.h, fahlbusch, v. & mein, p. (eds.): european neogene mammal chronology, plenum, 135-180, new york. stevanovi∆, p.m. (1951): pontische stufe im engeren sinne obere congerienschichten serbiens und der angrenzenden gebiete.serbische akademie der wissenschaften, sonderausgabe 187, matematisch-naturwissenschaftliche klasse, 1-351, beograd. stevanovi∆, p.m. (1961): pontische fauna mit limnocardium petersi bei kadar an der save (nord bosnien).annalés geologiqués da la péninsulé balkanique, 28, 177216, beograd. stevanovi∆, p.m. (1978): neue pannon-pontische mollusken arten aus serbien.annales geologiques de la péninsulé balkanique, 42, 315-344, beograd. stevanovi∆, p.m., nevesskaya, l.f. marinescu, a., soka», a. & jámbor, á. (eds.) (1990): chronostratigraphie und neostratotypen. neogen der westliche (“zentrale”) parathetys. 8. pontien.jazu-sanu, zagreb-beograd, 952p. strausz, l. (1941): a dunántúli pannon szintezése.földtani közlöny, 71, 220-237, budapest. strausz, l. (1971): pannóniai emelet (pliocén).földtani közlöny, 101, 114-119, budapest. szalay, a. & szentgyörgyi, k. (1979): adatok a szénhidrogénkutató fúrások által feltárt medencebeli pannon képzõdmények litológiai tagolódásának ismeretéhez trendelemzés alapján.az mta 10. oszt. közleményei, 12, 401-423, budapest. széles, m. (1962): alsópannóniai medenceüledékek puhatestû faunája.földtani közlöny, 92, 53-60, budapest. széles, m. (1971): a nagyalföld medencebeli pannon képzõdményei.in: goczan, f. & benkõ, j. (eds.): a magyarországi pannon kori képzõdmények kutatásai. akadémiai kiadó , 253-344, budapest. vakarcs, g., vail, p.r., tari, g., pogácsás, gy. , mattick, r.e. & szabo, a. (1994): third order middle miocene-early pliocene depositional sequences in the prograding delta complex of the pannonian basin.tectonophysics, 240, 81-106. wenz, w. (1942): die mollusken des pliozans der rumanische erdölgebiete.senckenbergiana, 24, 116-117. manuscript received march 23, 2000. revised manuscript accepted april 23, 2001. geo.cro.2-3-61-kb.pdf 363 � stjepko golubić1, crescenzo violante2, anđelka plenković-moraj3 and tonći grgasović4 ab stra ct travertines and calcareous tufa are porous deposits formed by interactions between ambient precipitation of calcium carbonate and resident organisms under different temperature regimes. the distinctions between travertine as thermal spring deposits and calcareous tufa (kalktuff) as deposits in the springs and rivers at ambient temperatures are fl uid. both represent end points in bioand physico-chemical calcifi cation processes across a broad gradient of temperature, mineral composition and ion saturation levels. ecological preferences of microand macroorganisms in travertine depositional systems result in the re-distribution of water fl ow, modifi cation of the landscape and its ecology. the resulting sedimentary structures include new environmental settings with different and diversifi ed biota. they also include different microenvironments of diagenesis with different timings of the processes involved. conditions in modern ambient temperature travertines of the plitvice system of lakes and waterfalls are compared with the similar, ancient system of rocchetta a volturno, in the central apennines. diagenetic alterations are described and illustrated starting with biologically identifi ed primary deposits. keywor ds: carbonate, diagenesis, freshwater, karst, micrite, precipitation, sparite, tufa, travertine 1 biological science center, boston university, 5 cummington str., boston, ma 02215, usa; (golubic@bu.edu) 2 institute for coastal marine environment, national research council, calata porta di massa porto di napoli, 80133 napoli, italy; (crevio@gms01.geomare.na.cnr.it) 3 department of biology, faculty of science, university of zagreb, rooseveltov trg 6, hr–10000 zagreb, croatia; (aplenk@zg.biol.pmf.hr) 4 croatian geological survey, sachsova 2, hr-10000 zagreb, croatia; (tgrgasovic@hgi-cgs.hr) travertines and calcareous tufa deposits: an insight into diagenesis geologia croatica 61/2–3 363–378 4 pls. zagreb 2008 geologia croaticageologia croatica � 1. introduction the term travertine has been used for centuries for porous building stone, desirable for its structural quality especially for the construction of vaults and arches (pentecost, 2005). the term derives from the latin lapis tiburtinus in reference to the town tibur, today’s tivoli, near rome, italy. the term was also used to designate inscriptions in stone of that origin. the porous stone of tivoli is still being quarried today, most of it originating from thermal springs of the area. the use of the name in geology has often been associated strictly with thermal spring deposits, whereas its ambient water counterpart is usually referred to as calcareous tufa (german: kalktuff, croatian: sedra). this distinction is diffi cult to maintain, because hydrothermal springs, range in temperature, and so do the processes of mineral precipitation. as thermal waters cool, carbonate precipitates change from predominantly aragonitic to calcitic and they become rapidly associated with a different microbiota of increasing diversity. travertine as building stone includes both hot spring and ambient temperature deposits. thus, for ecological as well as historic reasons, we prefer to use the term travertine for a range of sedimentary processes along the gradient of different temperatures, as has been the practice in the studies of the ambient temperature system of the plitvice lakes (srdoč et al., 1985). deposition of travertines and calcareous tufa in the region occurred at different times during interglacial and postglacial periods and remained geologia croatica geologia croatica 61/2–3 364 preserved in different stages of development (golubić, 1969). a review of travertine and tufa deposits of the world, listing occurrences in 22 european countries, is given by ford & pedley (1996), and they are common in the karstic region of croatia (e.g. primc-habdija et al., 2001; pavlović et al., 2002). travertines and calcareous tufa are considered excellent indicators of past climate conditions (e.g. peńa et al., 2000), an interest that has been recently triggered by the concerns about climate change. stable isotope and trace element analyses address these topics (lojen et al., 2004; kele et al., 2006; anzalone et al., 2007). diagenetic alterations of travertine deposits depend on microenvironmental infl uences and constitute a background relevant to the interpretation of the isotopic record (srdoč et al., 1983; andrews et al., 1997). this work studies the formation and early diagenesis of mineral products in biologically infl uenced sedimentary processes by recent-to-fossil comparisons, with examples from the plitvice travertine depositional system and from fossil travertine deposits of the river volturno, in the central apennines (golubic et al., 1993). 2. materials and methods live mosses, algae and cyanobacteria were collected in the cascades of the plitvice lakes system, and observed and identifi ed using light microscopy. their relation to carbonate deposits was studied using scanning electron microscopy (sem, jeolco, mbl, woods hole, ma) of critical point-dried specimens. live materials were decalcifi ed in dilute hydrochloric acid and studied by light microscopy. fossil deposits were collected in the plitvice national park and in fossil travertine deposits in the valley of the river volturno, italy. following macroscopic identifi cation at the site of deposition, samples were selected using an incident light dissecting microscope. selected samples were analyzed by sem with subsamples prepared as petrographic thin sections and studied by light microscopy (zeiss universal) using transmitted light, dic illumination and cross-polarized illumination. samples were studied and the results presented in order to illustrate the advancement of diagenetic alteration processes. 3. results and discussion 3.1. the geomorphology of travertine deposits the main distinction between thermal and ambient water travertine deposits is in the porosity. in thermal deposits, where precipitation is rapid, the porosity is produced by the trapped gas and by micrometer sized organisms embedded into the deposit. additional microstructure is produced by crystal growth (pentecost, 1990). ambient temperature systems attract, in addition to microorganisms, also mosses, insect larvae and plants, which shape the deposit leaving imprints and cavities of corresponding size. both systems commonly produce a calcareous deposit, characterized by an even distribution of water-fl ow and formation of pools behind carbonate barriers. both systems result in differentiation between lotic (running water, rapids), and lentic (relatively still water), environmental settings along streams and rivers. in thermal systems, carbonate precipitation predominates, guided by differential degassing, evaporation and cooling, favouring precipitation whe re the water is in direct contact with the atmosphere. the microorganisms are present but their contribution to the shapes of the deposits appears to be limited (pentecost, 1990 vs. chafetz & folk, 1984 and chafetz & guidry, 1999). the diversity and size of organisms increases with the lowering of temperature to ambient levels, and their role in carbonate deposition increases toward the establishment of chemical equilibrium in surface waters (merz, 1992; frančišković-bilinski et al., 2004). in thermal systems, the pools range from millimetre to metre scale, arranged step-wise down the slope, supported by smooth semicircular carbonate walls, over which the water overfl ows in a thin, evenly distributed fi lm (guo & riding, 1999, fi gs. 13, 17). in ambient temperature systems the formation of pools and barriers is less regular, but they are constructed by the same principle of differentiated carbonate deposition. the scale of participating organisms and of the resulting deposits is larger, and the timing is extended and subject to changes in seasons and meteorological conditions. the valley (thal) of the river that deposits calcareous tufa is modifi ed by the selective preference of calcifying rheophilic algae and mosses for growth in rapids, which are also the sites of maximum exchange of gases with the atmosphere. the growth of organisms, combined with carbonate deposition, produces a porous rapidly hardened substrate, which tends to partition the water fl ow. this results in the lateral displacement and fan-like distribution of both the deposit and the fl ow of water, ultimately extending across the river, forming a dam with a pool of water behind. this development has a regulatory effect as the water loses its erosional power, further promoting deposition and vertical growth of dams. the lakes grow larger by competition in barrier accretion in which the growth of lower barriers fl oods those upstream. once formed, the pooled water bodies became effective traps of eroded material (golubić, 1967, 1969). gradually, the river is transformed into a series of distinct lakes and waterfalls, and the initially inclined river bed is altered into a series of terraces. similar systems developed during pleistocene and early holocene throughout southern europe (e.g. peńa et al., 2000), but few remained active. different stages in the progression of this development can be observed in the plitvice system of alternating lakes and waterfalls (plate 1, fig. 1). impressive waterfalls (pl. 1, fig. 2) are the exception rather than the rule in this development, which normally tends to subdivide the water passages and distribute them in a net-like fashion over the entire barrier, a condition which supports the growth of higher plants and trees. yet, the barriers may become unstable and collapse, changing the water passages abruptly. massive waterfalls may be created by occasional erosional events or, more often, by humans, in order to guide the water to their water mills or to maintain waterfalls for a tourist attraction. the shallow fl at-bottomed ponds between smaller barriers, initially support rapid water exchange and create conditions in which carbonate accumulates in microbially coated grains and forms laminated nodules or oncoids (golubic geologia croaticastjepko golubić et al.: travertines and calcareous tufa deposits: an insight into diagenesis 365 & fischer, 1975; pedley, 1990; hägele et al., 2006). within the plitvice system, oncoids are sporadically present along shallow fl at shorelines of lake kozjak, and also as large fi elds in slow fl owing widened areas of the river slunjčica at rastoke (pl. 1, fig. 3). they are dominated by cyanobacteria and microscopic algae. such shallow ponds deepen over time through the vertical growth of barriers between them (pl. 1, fig. 4) and then accumulate fi ne carbonate sand, which supports aquatic plants such as myriophyllum spicatum l. with charophytes on the shallower pond margins. some water passages elevate their bed while maintaining the fl ow on top of a carbonate ridge. these, so called “cat walk” deposits (german: kalkrinnen) are often products of small, carbonate supersaturated springs that emerge on slopes (pl. 1, fig. 5). this represents another depositional feature that is similar in both ambient temperature and hot water deposits (see guo & riding, 1999). carbonate precipitates a certain distance from the spring as soon as the carbonate equilibrium shifts in favour of precipitation. there is a preference of moss growth and associated deposition of carbonate in the spray at the margins of such water fl ows. consequently, the creek bed is elevated while the margins prevent lateral overfl ow. over time, the “cat walk” fl attens in the upper ranges while it steepens distally. the lateral overfl ow and displacement occurs with a delay so that the deposits ultimately widen to produce semiconical tufa structures called “crone” or “cranier” in french, and “hangtuff” in german. the plitvice system of lakes and waterfalls developed in a valley overlying the triassic dolomites, which narrows downstream into a canyon carved into cretaceous limestone (golubić & grgasović, 2007). the upper lakes are wider and the ponds occupy different levels. the fossil sites at rocchetta a volturno occur on slopes of an even wider valley and developed, accordingly, in the form of an extended set of terraces with steeper slopes and waterfall facies on their outer margins. similar systems have been described in antalia, turkey (glover & robertson, 2003). 3.2. the constructive role of aquatic mosses aquatic mosses such as cratoneurum commutatum (hedw.) roth, eucladium verticillatum (with.) bruch & schimper, bryum pseudotriquetrum (hedw.) p. gaertn., b. mey & scherb. and didymodon tophaceus (brid.) jur. are known as travertine-forming organisms. they thrive in the water spray in waterfalls where they become encrusted by carbonate. by their growth preferences, the mosses guide the precipitation and modify the fl ow of water (pl. 1, fig. 6). however, the carbonate encrustation takes place on older leafl ets and on the moss stems rather than on young actively growing leafl ets (pl. 1, fig. 7), which suggests that there is no direct relationship between moss photosynthesis and carbonate deposition. instead, mosses are stimulated to grow at their tips so as to escape being cemented in carbonate. in contrast, the carbonate precipitate is associated with a biofi lm of microorganisms, which overgrows the moss with age. some carbonate deposited in the moss cushions is allochthonous, i.e. precipitated upstream and then trapped by the moss. carbonate precipitation starts on crystallization nuclei provided by the microbial biofi lm of cyanobacteria, diatoms and microscopic chlorophytes, such as the desmid oocardium stratum (pl. 1, fig. 10). similar microbial biofi lms coat the branches and leaf litter trapped in the waterways (pl. 1, fig. 7). encrusted by carbonate, the moss cushions form porous sponge-like carbonate sediment that retains the shape of the moss and fossilizes instantly, often incorporating other plant material (pl. 1, fig. 8). as the calcifi cation continues, the mosses respond by growing out of the deposit. in the race that ensues between moss growth and calcifi cation, the latter is shaped and directed by the growth of mosses which, in turn, follow the water currents, cascades and spray. the porous spongy consistency of moss thalli provides the architectural framework for the travertine deposit. the environmental requirements of rheophilic aquatic mosses promote their settlement in rapids and cascades, where they become encrusted by carbonate. such biologically controlled deposition is contrary to the pattern of inorganic deposition of particulate matter. in addition, the presence of mosses in travertine deposits organizes rock porosity at scales ranging from mm-size spaces between moss leafl ets and stems to cmand metre-scale cavities and caves formed under cascades and waterfalls. the environmental consequence of moss participation is the formation of a voluminous travertine structure from relatively small amounts of carbonate mineral, which would otherwise form compact crusts, similar to cave stone (golubic, 1973). due to the rheophily of aquatic mosses and microorganisms, carbonate accumulates in rapids rather than in pools and depressions where it is deposited as fi ne particulate matter (calcilutite). fossil travertine of both thermal and ambient temperature systems has been used in architecture since ancient times as seen in the ruins of pompeii and in the doric greek temples of magna grecia, in present southern italy (pl. 1, fig. 9). the landscape modifi cation by the combined activity of aquatic mosses, eukaryotic microorganisms such as oocardium stratum (pl. 1, fig. 10), and calcifying cyanobacteria (pl. 1, fig. 11) has important ecological consequences, as new niches and opportunities for growth arise that did not previously exist in the river. the water behind travertine dams accumulates as lakes with their own communities of plankton, benthos and littoral, which are alien to fast fl owing rivers. vaults of travertine that support, (and are shaped by) waterfalls, overhang and enclose cave spaces beneath them (pl. 1, fig. 2), with new habitats provided with trickling water and a humidity-saturated atmosphere, able to support a luxurious microfl ora of cyanobacteria and algae specialized to photosynthesize under dim illumination, e.g. scytonema julianum (kützing) meneghini, s. myochrous (dillw.) agardh (pl. 1, fig. 11) and petalonema alatum berkeley (pl. 1, fig. 12). the spongy porous deposit becomes a home to bacteria as well as to numerous minute invertebrates that thrive on the organics produced in the system and are carried by waters trickling through the porous deposit. these developments derive from the growth preferences and adaptive capacity of aquatic mosses (pl. 2, fig. 1), which are in that sense the real architects of cold water travertine deposits (arenas et al., 2000). mosses fossilize well and identify past environmental geologia croatica geologia croatica 61/2–3 366 plate 1 calcareous tufa formations and their microbiota 1 view of the two lowermost lakes of the plitvice system of korana river, kaluđerovac and novakovića brod, separated by a low barrier. 2 water falls down the tall travertine barrier in the upper parts of the plitvice system, “mali prštavac” waterfall. note the overhanging tufa enclosing caves under the water arches. 3 shallow ponds with high water exchange rates in a part of the water-fl ow network of the river slunjčica, a tributary of the korana (rastoke village), supporting a “pavement” of oncoids. insert: two of the oncoids, the right one cut open to show the laminated internal texture. scale bar is 1 cm long. 4 a series of small tufa barriers with cascades, separating shallow ponds, lower lakes. 5 “cat walk”type calcareous deposit in a small carbonate super-saturated spring located on a hill slope. 6 luxurious cushions of the moss cratoneurum commutatum, growing in the water spray and participating in the even distribution of water along the barrier. scale bar is ca 20 cm long. 7 a leaf of alnus glutinosa trapped in the cascade and overgrown by globular oocardium colonies. scale bars in fi gs 7, 8 and 9 are 1 cm long. 8 fossil calcareous tufa with cavities and incorporated branches of trees fallen into the lakes. 9 doric temple in paestum, southern italy, built of ambient water travertine that preserves aquatic mosses. 10 cells of oocardium stratum inserted in the calcifi ed tubes, forming a single layer of cells on the surface of each colony. 11 two species of scytonema (cyanobacteria). the smaller one on the upper left is calcifi ed s. julianum next to the larger uncalcifi ed s. myochrous below. 12 the nitrogen fi xing cyanobacterium petalonema alatum forms soft gelatinous colonies in the moist cave entrances underneath the waterfalls. note the diff erently pigmented nitrogen-fi xing heterocyst in the centre. scale bars in fi gures 10, 11 and 12 are 10 μm long. geologia croaticastjepko golubić et al.: travertines and calcareous tufa deposits: an insight into diagenesis 367 geologia croatica geologia croatica 61/2–3 368 changes such as seasonal rhythms or the lateral displacement of depositional regimes (pl. 2, fig. 2), often preserving the taxonomic identities of ancient travertine builders (pl. 2, fig. 3). 3.3. the role of cyanobacteria and micro-algae a closer look at the moss leafl et surfaces reveals a biofi lm of cyanobacteria and diatoms in close association with calcite crystals (pl. 2, fig. 4). in addition to aquatic mosses, the other most-important organisms involved in the formation of ambient water travertine are cyanobacteria and eukaryotic algae, which form biofi lms and promote calcifi cation (pl. 2, figs. 5– 7). without their contribution, precipitation of calcium carbonate would still occur, but the precipitate may not be retained in rapids, but transported downstream instead. experiments with exposed copper grids that are toxic to micro organisms and do not support biofi lm development also remain uncalcifi ed (srdoč et al., 1985). calcifi cation on exposed slides shows a positive linear correlation with the rates of periphyton growth (primc-habdija et al., 2001). species-specifi c differences in the degree of calcifi cation and in the shape of the resulting calcium carbonate crystals have been documented in cases of freshwater (obenlüneschloss & schneider, 1991) as well as marine cyanobacteria (golubic & campbell, 1981). similar cases of biological crystal specifi city have been documented in ambient water travertines (e.g. golubic et al., 1993). while some cyanobacterial species calcify, other species remain uncalcifi ed, although growing under the same conditions and in close proximity to each other (pl. 1, fig. 11). in order to investigate the role of microphytes in the process of tufa deposition in the plitvice lakes national park area, qualitative and quantitative analyses of periphyton were carried out between 1985 and 1990 (plenković et al., 2002). the connection between carbonate deposition and periphyton was tested by experimental exposure of microscope slides. glass slides were submerged in streaming water and exposed for 30, 60, and 90 days. seven locations with different intensities of natural tufa deposition were chosen along the plitvice lake system. temperature, ph and current were monitored simultaneously. growth of periphyton was analyzed, and 191 species were determined with the highest diversity being shown by diatoms (139 species). the dominance of diatom species was observed at all locations (especially in winter), irrespective of changes in physicochemical properties of the water and the intensity of caco3 precipitation. a particularly intensive precipitation of microcrystalline calcite was found in the presence of cyanobacteria: chamaesiphon incrustans grunow, homoeothrix varians geitler, hydrococcus rivularis mene ghini, and diatoms: achnanthes affi nis grunow, a. microcephala grunow, a. pyrenaica hustedt, synedra vaucheriae kützing, cymbella affi nis kützing, c. microcephala grunow, gomphonema olivaceum kützing, g. olivaceum var. calcareum cleve, and g. parvulum grunow. in addition to physicochemical and geological factors, the qualitative composition and density of the microphyte community appeared to be of major importance in the formation of tufa. however, recent massive developments of different benthic diatoms in the plitvice lake system associated with an increase in nutrients correlate instead with a decline in calcifi cation intensity, especially in smaller pools on top of the barriers (unpublished observation). calcite precipitation by diatoms (pl. 2, fig. 6), is associated more directly with cell products than their photosynthetic activity, which is less evident with cyanobacteria where the calcifi cation occurs on extracellular sheaths enveloping the cells (pl. 2, fig. 6, insert). diatoms are ubiquitous epiphytes on mosses (pl. 2, fig. 7), but are themselves overgrown by smaller microorganisms such as bacteria (pl. 2, fig. 7, insert). crystal growth takes place around gelatinous stalks produced by the cells of the diatom gomphonema olivaceum var. calcareum cleve, and are arranged in stromatolitic laminae through pulses of diatom growth (winsborough & golubic, 1987). this relationship between a microbial product and crystal nucleation is consistent with the concept of organomineralization sensu trichet (1967) and défarge & trichet (1993). initiation of calcite precipitation on moss leafl et surfaces without the presence of microbial epiphytes, but associated with organic templates of apparent microbial origin, has been recently described by turner & jones (2005). this particular pattern of “dendritic” calcite precipitate has been described earlier and associated with a schizothrix sp. in the everglades, florida (merz & zankl, 1993). we found the same crystallization pattern associated with the sheaths of the subaerial cyanobacterium geitleria calcarea friedmann, which inhabits the semi-enclosed caves in the travertine barriers, beneath the waterfalls (pl. 2, fig. 8). the crystallization follows the mineral lattice of calcite, but favours sharp crystal edges over the plates, which are completed later (pl. 2, fig. 9). dominant assemblages of cyanobacteria and diatoms are present in different natural habitats along the system according to their specifi c adaptations and growth preferences. the exclusive domain of cyanobacteria is on travertine cones under the waterfalls, which receive the direct impact of falling water. these microorganisms are structurally supported by carbonate deposition in and around their extracellular sheaths and envelopes. the associated carbonate deposit is more compact than that forming around mosses, with a fi ne, micrometer-scale porosity provided by the fi laments of cyanobacteria. the most common among these carbonate-encrusted cyanobacteria are phormidium incrustatum (nägeli) gomont. we have followed the early stages in encrustation of this organism in the plitvice travertines (pl. 2, fig. 6, insert and fig. 10), as well as early and late diagenetic changes (see below). other cyanobacteria that show different degrees of calcifi cation in the plitvice system are schizothrix fasciculata (nägeli) gomont, and the moderately encrusted phormidum favosum (bory) gomont, p. uncinatum gomont and hydrocoleum homoeotrichum kützing, these organisms are common in rapidly fl owing channels over and around travertine barriers. similar habitats show frequent growth of hemispherical colonies of rivularia haematites (de candole) agardh, hardened by the dense zonal deposition of calcite grains. a specifi c difference in carbonate precipitates in this and other freshwater species of rivularia has been documented by obenlüneschloss & schneider (1991). geologia croaticastjepko golubić et al.: travertines and calcareous tufa deposits: an insight into diagenesis 369 high rates of calcifi cation, as well as a species-specifi c modifi cation of precipitates, are shown by chlorophytes, especially by the desmid oocardium stratum and the xanthophyte vaucheria geminata (vauch.) de candolle. these cases have been selected in the present study of diagenesis (see below). although subject to numerous investigations, the deposition of calcareous tufa in karstic waters remains incompletely explained. the problem stems largely from different interpretations of the biogenic vs. abiogenic components which are responsible for calcifi cation and the formation of travertines. to approach this question in a constructive fashion requires realization of the complexity of the process, and its sequential development. the environmental conditions such as ph, carbonate chemistry and saturation levels of solutions change as a part of this process and so do the nature and proportion of biogenic vs. abiotic infl uences. an average carbon atom engaged in this process, passes through the phases of (a) carbonate chemistry, (b) nucleation, crystal organization and growth, and (c) accumulation and build-up of carbonate sediment. each of these phases may be responding to a different balance of biogenic vs. abiotic forces, and they may infl uence each other sequentially (golubic, 1973; emeis et al., 1987). carbonate deposition is a process at the intersection of inorganic and organic carbon cycling, which ranges in scale from molecular to global (golubic et al., 1979; golubic & schneider, 1979). the supersaturation of karstic springs, which is the prerequisite for carbonate precipitation, is largely biogenic by enrichment with respiratory co2 in soils. the precipitation of carbonate that follows the emergence of these waters is part of the adjustment of the preceding biogenic carbonate dissolution. the extensive fossil tufa deposits of roccheta a volturno, used here in the current recent-to-fossil comparison, are no longer actively accumulating, since the slopes of the watershed have been deforested and the soils washed out (d’argenio et al., 1995). the barriers of the plitvice lake system are still in the process of active accretion (zwicker & rubinić, 2005), within its densely forested watershed largely protected by its national park status. a predominance of “abiotic” infl uences on carbonate precipitation (e.g. chen et al., 2004), is expected at a relatively short distance from the spring, as part of the re-adjustment of excessive (respiratory) co2 transported in the ground waters to the pco2 of the atmosphere. it is promoted by increase of the air-water interface in waterfalls (zhang et al., 2001). in the hard calcite-saturated waters of the plitvice lakes system, locally strong aeration promotes considerable calcium carbonate precipitation. the predominance of biogenic infl uences on carbonate che mistry through microbial photosynthetic activity is expected later in the water fl ow, after equilibrium with the atmosphere has largely been reached (merz-preiss & riding, 1999; frančišković-bilinski et al., 2004). the microbial biogenic infl uences on crystal nucleation and construction of minerals are separate from the carbonate chemistry (freytet & verrecchia, 1998), and operate at a much fi ner scale than the sedimentary processes under the infl uences of aquatic mos ses, the latter producing the macroarchitecture of travertine deposits. 4. diagenesis in travertine deposits diagenesis of travertine deposits starts early and proceeds unevenly. it is initiated contemporaneously with travertine barrier building, as calcifi cation instantly fossilizes the biological structure. further diagenesis is conditioned by the very porosity of the deposit. as water seeps through the travertine, the gravitational fi eld determines its passage, so that some conduits are in frequent use, while other parts of the porous sediment are avoided and remain unaffected. as in soils, the interstitial waters in travertine barriers collect respirational co2 and may dissolve some of the carbonate deposit, which subsequently precipitates when equilibrium with atmospheric pco2 is re-established (golubić, 1969, 1973). the process is similar to the deposition of stalactites in caves: it produces a coating of compact crystalline carbonate over travertine that becomes superfi cially indistinguishable from cavestone (pl. 1, fig. 8, smooth surfaces). at a microscopic scale, minute details in the travertine deposit become dissolved or re-arranged, gradually losing original texture and biogenic signature. as part of the same process, other places within the travertine structure remain unchanged. this condition permits comparison between different stages of the diagenetic process, which have been arrested and preserved by the changes of water passage. preserved thalli of interglacial and early holocene cratoneurum commutatum remain preserved and recognizable in the caves of the waterfall facies of the roccheta a volturno deposits (pl. 2, fig. 11). similarly, the stromatolitic laminae of alternating chironomid housings and zones of oocardium stratum, testify to seasonal changes on the travertine slopes at the same fossil site (pl. 2, fig. 12), as discussed by golubic et al. (1993, 1995), and documented by stable isotope measurements (anzalone et al. 2007). 4.1. diagenesis of the micrite deposit of phormidium incrustatum (cyanobacteria) diagenetic alterations in sites exposed to direct water impact show considerable variation, as shown in calcifi ed colonies of the cyanobacterium phormidium incrustatum (pl. 3, fig. 1). when active, fi laments of p. incrustatum are composed of sheathed trichomes, about 4 μm in diameter. the trichomes are surrounded by a fi rm sheath of extracellular polymers (eps), which are the locus of intensive calcifi cation. filaments are often arranged parallel to each other, forming upright bundles that jointly resist the water impact. the bundles build colonies in the form of lens-shaped cushions, two to three cm in diameter, slightly inclined in the direction of water fl ow (pl. 3, fig. 2). in petrographic thin section under unpolarized and polarized transmitted light, the outlines of these fi laments appear dark due to the densely arranged grains of micritic calcite (golubic et al., 1993, pl. 2, fi gs. 5, 8). in sections perpendicular to the direction of bundles, the fi laments seen in cross section are similarly outlined by primary micrite, whereas the spaces between bundles are fi lled with sparry calcite (pl. 3, fig. 3). fractured samples along the bundles as seen by sem, (pl. 3, fig. 4), reveal uniformly distributed calcifi ed tubes of empty sheaths preserved as micritic linings. geologia croatica geologia croatica 61/2–3 370 plate 2 aquatic mosses and biofi lms, the main architects of calcareous tufa 1 cratoneurum commutatum dominates the cascades of the plitvice system. scale bar is ca 5 cm long. 2 fossil moss, bryum pseudotriquetrum, forming distinct, apparently seasonal laminae on the travertine slopes at rocchetta a volturno, central apennines. 3 well preserved fossil moss plantlets of eucladium verticillatum near calcareous waterfalls at tivoli, italy. scale bar is 1 cm long. 4 critical-point dried moss plantlets under scanning electron microscope (sem). note the dense overgrowth of microorganisms forming an epiphytic biofi lm. scale bar is 100 μm long. 5 the tip of a moss leafl et coated by microbial biofi lms dominated by leptolyngbya (cyanobacteria), and sessile eukaryotic green algae and diatoms. scale bar is 10 μm long. 6 detail of the biofi lm, dominated by pinnate diatoms and associated carbonate precipitates. insert: heavily calcifi ed tube formed by the cyanobacterium phormidium incrustatum. scale bar is 10 μm long, also for the insert. 7 tip of a diff erent moss leafl et densely covered by synedra (bacillariophyta), insert: heterotrophic bacteria overgrowing the diatom. scale bar is 50 μm for the leafl et and 20 µm for the insert. 8 calcifi ed sheaths of the cyanobacterium geitleria calcarea and g. fl oridana growing subaerially in the semienclosed caves under the waterfalls. 9 detail of the sheaths shown in fi g. 8, illustrating distinctive fi brous growth of the calcite crystals. scale bar is 1 μm long. 10 early growth stages of phormidium incrustatum (cyanobacteria) with heavily calcifi ed sheaths (see insert in fi g. 6). scale bar is 50 μm long. 11 fossil lithifi ed moss (cratoneurum commutatum) comprising a cave ceiling in the waterfall facies of roccketta a volturno. the details are suffi ciently well preserved to identify the fossil organism. 12 interglacial stromatolitic travertine on the slope facies of rocchetta a volturno showing seasonal deposition of oocardium stratum, alternating with housings of chironomid larvae. oocardium settles every june, following chironomid maturation. geologia croaticastjepko golubić et al.: travertines and calcareous tufa deposits: an insight into diagenesis 371 geologia croatica geologia croatica 61/2–3 372 plate 3 diagenesis of a calcareous deposit of phormidium incrustatum 1 calcifi ed cushions of phormidium populations which dominate areas with a strong impact of falling water. the fl ow of water and orientation of the cyanobacterial fi laments are toward the observer. scale bar is 5 cm long. 2 section through the cushions of phormidium in side view; the direction of water fl ow is from left to right. scale bar is 1 cm long. 3 petrographic thin section perpendicular to the fi lament orientation. note dark micritic outlines of cyanobacterial sheaths and large sparitic fi ll of the interfi lament spaces. scale bar is 20 μm long. 4 longitudinal fracture through a bundle of phormidium fi laments preserved as calcifi ed tubes. scale bar is 20 μm long. 5 early stages of diagenesis of phormidium travertine. note that the recrystallization starts in the interior of the bundles and progresses outward. peripheral fi lament imprints are perfectly preserved whereas the interior appears as a solid carbonate block. scale bar is 100 μm long. 6–8 advanced diagenetic alteration of phormidium travertine. scale bars are 50 μm long 6 petrographic thin section through an altered bundle of phormidium. note the pseudostromatolitic lamination stained by bands of concentrated iron precipitate alternating with clear zones. 7 the same frame in cross polarized transmitted light shows the uniform optical orientation of the entire column as a single crystal. 8 large monocrystalline palisades originated from bundles of phormidium fi laments. fig. 8 represents further development of the stage shown in fi g. 5 above. geologia croaticastjepko golubić et al.: travertines and calcareous tufa deposits: an insight into diagenesis 373 geologia croatica geologia croatica 61/2–3 374 plate 4 calcareous deposition by oocardium stratum and vaucheria geminata 1 detail of a micro-reef produced by oocardium showing monocrystalline calcareous tubules that branch with each cell division of the desmid. scale bar is 50 μm long. 2 petrographic thin-section through an upright colony of oocardium in cross polarized light. note that crystal orientation is the same for each clonal population of the alga. 3 similarly fractured upright colony seen by sem. scale bars in fi gs. 2 and 3 are 100 μm long. 4 detail of the rim of the ocardium calcareous tube following hypochlorite treatment to remove organic components. note the orientation of the cleavage pattern is consistent with a single calcite crystal and the cylindrical imprint of the organic tubule. scale bar is 5 μm long. 5 critical-point dried clonal colony of ocardium stratum showing cells in the state of division inserted into calcareous tubes. scale bar is 30 μm long. 6 early diagenetic alteration of an oocardium calcite grain. note the euhedral outline of the grain, while its interior contains the original tubules. scale bar is 50 μm long. 7–9 three advanced stages in diagenetic alteration of an oocardium colony. scale bars in these fi gures are 1 mm long. note the gradual increase in the average size of calcite grains, while their upward divergence remains preserved. 10–15 calcifi ed fi laments of vaucheria geminata; fig. 10 – sem view of the calcifi ed network of vaucheria fi laments; fig. 11 – a fractured group of heavily calcifi ed fi laments; fig. 12 – a single fi lament of vaucheria with the residue of the cell wall visible inside the calcifi ed tube. note the radial arrangement of microspar grains encrusting the fi lament. scale in figs. 10–12 is 100 μm long; fig. 13 – petrographic thin-section of diagenetically altered vaucheria fi laments; fig. 14 – sem of broken vaucheria travertine obliquely cutting the calcareous tubes; fig. 15 – petrographic thin-section of a calcifi ed vaucheria fi lament in cross section. scale bars in figs. 13–15 are 50 μm long. geologia croaticastjepko golubić et al.: travertines and calcareous tufa deposits: an insight into diagenesis 375 geologia croatica geologia croatica 61/2–3 376 diagenetic changes of phormidium incrustatum deposits are accompanied by gradual recrystallization, within which the size of calcite grains increases. this process usually starts in the centres of fi lament bundles and spreads toward the bundle periphery. this stage is shown in pl. 3, fig. 5, where the left side of the image contains bundles unaffected by recrystallization, whereas two bundles to the right are cleaved and show compact interiors, while the periphery of each bundle preserves individual tubules of the original biogenic imprint. in later stages of diagenesis, observed in those parts of the same sample that were affected by serving as a water conduit, the original biogenic signature is completely erased (pl. 3, figs 6–8). in plain transmitted light, a petrographic thin section along the bundle shows pseudostromatolitic structure with rhythmic lamination of iron enrichment lines (pl. 3, fig. 6). the same section in cross-polarized light (pl. 3, fig.7) reveals that the entire pseudostromatolite is comprised of a single crystal grain. the diagenetically altered phormidium incrustatum bundles as shown by sem (pl. 3, fig. 8), are converted into large calcitic palisades with external outlines of the original bundles smoothed but still recognizable. this observed diagenetic sequence is invariably trends towards an increase in the average carbonate grain size, whereas the preserved micritic carbonate identifi es the parts of the original mineralogy. there was no evidence of secondary micritization in this process. 4.2. diagenesis of primary sparite of oocardium stratum (chlorophyceae) diagenesis of fossil oocardium tufa has been reported and discussed by golubic et al. (1993). the present study compares the process with other biogenically modifi ed primary precipitates. the desmid oocardium stratum is a common constituent of ambient temperature travertines. its life cycle, growth patterns and ecology have been studied since the 1930s (wallner, 1933, 1934). in the karstic region of croatia, it was fi rst observed by ivo pevalek, an early explorer of the plitvice system, and later found in the travertine deposits of the river krka (pavletić & golubić, 1956). its taxonomic status was subsequently clarifi ed by golubić & marčenko, (1958). the characteristic calcifi ed light green colonies (pl. 1, fig. 7) of oocardium form contiguous microscopic reefs (golubic et al., 1993, pl. 3). the extracellular polymers produced by this unicellular green alga form a ring around the cell, which starts calcifying by organizing a single calcite crystal that conforms to the shape of the organic ring. as the production of the polymer continues, the cell is lifted from the substrate, carried by a calcifi ed tube. as the cell divides, the tube branches (pl. 4, fig. 1), while continuing the orientation of the monocrystalline lattice. ultimately, the entire clonal colony produces a single calcite spar crystal, as evident by cross-polarized light microscopy (pl. 4, fig. 2) compared with sem images (pl. 4, fig. 3). the combined biological and mineralogical characteristic of the mineral is illustrated in pl. 4, fig. 4, showing uniform orientation of calcite cleavage lines, combined with the round shape of the organic tubule. an entire clonal colony with its mineral product is shown in the sem of a criticalpoint-dried preparation (pl. 4, fig. 5). diagenetic alteration of these primary spars starts by recrystallization of the external parts, from where it proceeds toward the interior. the exterior of altered spars (pl. 4, fig. 6) gains a rhombohedral morphology typical of pure calcite, whereas the interior still preserves the tubular imprint of the original oocardium tubules. the same has been shown in petrographic thin sections (golubic et al., 1993, pl. 4, fi gs. 4–10). advanced stages of diagenetic recrystallization are illustrated in pl. 4, figs. 7–9. note that these three fi gures are at the same low magnifi cation. the recrystallization resulted fi rst in the complete loss of the internal tubular structure, reta ining only “clonal” crystalline identities in the form of wedge -shaped grains (pl. 4, fig.7). the next step resulted in re-organization of the grains toward a radial symmetry with pseudostromatolitic zonation (pl. 4, fig. 8). this stage has certain morphological properties similar to those shown in the diagenetic sequence of phormidium incrustatum (compare with pl. 3, fig. 5) suggesting convergent diagenetic modifi cation starting from different original precipitates. this convergence is further supported by the next stage (pl. 4, fig. 9). 4.3. diagenesis of microsparites of vaucheria geminata (xanthophyceae) large colonies of the fi lamentous xanthophyte (heterocontae) vaucheria geminata are regularly calcifi ed, forming large spongy travertine deposits that compare in volume with mosses (pl. 4, fig. 10). the organism is characterized by tubular fi laments without cross walls which occasionally branch. reproductive organs are carried on short side branches. in travertine depositing systems, the cell walls of vaucheria fi laments are rapidly covered by calcite crystals, which continue to grow outward until they reach a fairly uniform size, intermediate between phormidium micrite and oocardium sparite (pl. 4, figs. 11, 12). the petrographic thin section images (pl. 4, figs. 13, 15) agree well with the sem images. this type of encrustation apparently results from competing growth of synchronously seeded calcite grains, in which only the initial nucleation is under the control of the cell wall composition (pl. 4, fig. 14), whereas further growth of crystals continues under supersaturation of interstitial waters, competing for space. the average size of grains gradually increases from the cell wall surface outward (pl. 4, figs. 12, 15). by comparing different stages in diagenetic alteration, we again observed the same pattern of grain size increase following recrystallization as in other examples, although the initial stages are species-specific and quite different from each other. 5. conclusions the formation of thermal and ambient water travertines have the following properties in common: even distribution of water and modifi cation of the fl ow into pools separated by walls of carbonate deposit. in the ambient temperature tufa of the plitvice system, carbonate precipitation shows differences specifi c to particular microorganisms, whereas the travertine barriers are constructed by mosses. diagenetic alteration of primary precipitates starts contemporaneously with carbonate geologia croaticastjepko golubić et al.: travertines and calcareous tufa deposits: an insight into diagenesis 377 deposition, but depends on the later access of water. in the porous calcareous tufa, diagenesis is uneven, and primary precipitates remain locally preserved. diagenetic changes are derived from recrystallization of primary precipitates and from secondary coating of the structures by cave-stone type deposits. diagenetic recrystallization leads convergently toward an increase in the average carbonate grain size. no evidence of secondary micritization processes was found. the present study has identifi ed several active environments within the plitvice travertine system that correspond to lithofacies assemblages described from quaternary travertines in the central apennines (ferreri, 1985; d’argenio & ferreri, 1987), reviewed by golubic et al. (1993). lithofacies assemblages of lentic environments described as (1) calcareous sands with travertine intercalations, are observed in the plitvice system in smaller deeper ponds separated by barriers that are arranged in terraces between larger upper lakes. (2) phytoclastic calcarenite and phytohermal travertine with phanerogam fragments characterize shallow lentic conditions (quiet waters). within this lithofacies assemblage, we have identifi ed an oncolitic setting (pl. 1, fig. 3). a further four lithofacies associations refer to habitats and biota in lotic (fast fl owing) environments with an increasing slope angle, as a consequence of accretion of travertine barriers. the most conspicuous feature is the stromatolitic type of lamination, which characterizes (3) phytoclastic packstone-grainstone and stromatolitic travertine organized in lensoid and tabular bodies. within this lithofacies, we have studied modern oocardium in association with “bibliolitic” travertine, (layered carbonate-encrustged phanerogame leaf litter), on the edges of cratoneurum facies. in the plitvice system this environment is localized in parts of the barrier with gradual slope. (4) phytoclastic rudstone with microhermal and stromatolitic travertine with moss cushions and (5) micro-phytohermal and stromatolitic travertine with grasses are the two most widespread environments dominating on all the barriers of the plitvice system. within the above environmental context, the present study has uncovered the taxonomic identity of one of the fossil deposits reported by golubic et al. (1993, p. 236, pl. 2, fi g. 8) as vaucheria geminata (pl. 4, figs. 10–15). the sequences of the travertine lithofacies combinations described above, when superimposed in a vertical sedimentary section do not refl ect a change in climatic conditions. instead, they are consequence of the lateral displacement of waterways and sedimentary environments, which are part of the normal depositional processes in travertines. a model illustrating these processes has been proposed (golubić, 1969; golubic et al., 1993) and was more recently documented by deep ground penetrating radar analysis (pedley et al., 2000). references andrews, j.e., riding, r. & dennis, p.f. (1997): the stable isotope record of environmental and climatic signals in modern terrestrial microbial carbonates from europe. – palaeo., palaeo., palaeo., 129, 171–189. anzalone, e., ferreri v., sprovieri, m & d’argenio, b. (2007): travertines as hydrological archives: the case of the pontecagnano deposits (southern italy). – adv. water resour., 30, 2159–2175. arenas, c., gutierres, f., osacar, c. & sancho, c. (2000): sedimentology and geochemistry of fl uvio-lacustrine tufa deposits controlled by evaporite solution subsidence in the central ebro depression, ne spain. – sedimentology, 47, 883–909. chafetz, h.s. & folk, r.l. (1984): travertines: depositional morphology and the bacterially constructed constituents. – j. sediment. petrol. 54/1, 289–316. chafetz, h.s. & guidry, s.a. (1999): bacterial shrubs, crystal shrubs, and ray-crystal shrubs: bacterial vs. abiotic precipitation. – sediment. geol., 126, 57–74. chen, j., zhang, d.d., wang, s., xiao, t. & huang, r. (2004): factors controlling tufa deposition in natural waters at waterfall sites. – sediment. geol., 166, 353–366. d’argenio & ferreri (1987): a brief outline of sedimentary models for pleistocene travertine acumulation in southern italy. – rend. soc. geol. it., 9, 167–170. d’argenio, b., violante, c., & golubic, s. (1995): travertines as proxies to climate controlled/controlling carbonates in geologic time. an introduction. – in: ubertini, l., castelli, f. & bras, r.l. (eds.): climate change and hydrogeological hazards in the mediterranean area. nat. res. council of italy, perugia, 17–23. défarge, c. & trichet, j. (1993): from biominerals to organominerals: the example of the modern lacustrine calcareous stromatolites from polynesian atolls. – in: allemand, d. & cuif, j.p. (eds.):7th international symposium on biomineralization. musee oceanographique, monaco, vol. sp 14/2, 265–271. emeis, k.c., richnow, h.h. & kempe, s. (1987): travertine formation in plitvice national park, yugoslavia: chemical versus biological control. – sedimentology, 34, 595–609. ferreri, v. (1985): criteri di analisi di facies e classifi cazione dei travertine pleistocenici dell’italia meridionale. – rend. acc. scienze. fis. e mat. (napoli), 52, 1–47. freytet, p. & verrecchia, e.p. (1998): freshwater organisms that build stromatolites: a synopsis of biocrystallization by prokaryotic and eukaryotic algae. – sedimentology, 45, 535–563. ford, t.d. & pedley, h.m. (1996): a review of tufa and travertine deposits of the world. – earth–sci. rev., 41, 117–175. frančišković-bilinski, s., barišić, d., vertačnik, a., bilinski, h. & prohić, e. (2004): characterization of tufa from the dinaric karst of croatia: mineralogy, geochemistry and discussion of climate conditions. – facies, 50, 183–193. freytet, p. & verrecchia, e.p. (1998): freshwater organisms that build stromatolites: a synopsis of biocrystallization by prokaryotic and eukaryotic algae. – sedimentology, 45, 535–563. glover, c. & robertson, a.h. (2003): origin of tufa (cool-water carbonate) and related terraces in the antalya area, sw turkey. – geol. j., 38, 329–358. golubić, s. (1967): algenvegetation der felsen, eine ökologische algenstudie im dinarischen karstgebiet. – binnengewässer, 23, 1– 183. golubić, s. (1969): cyclic and noncyclic mechanisms in the formation of travertine. – verhandl. internat. verein, limnol., 17, 956–961. golubic, s. (1973): the relationship between blue-green algae and carbonate deposits. – in: carr, n.g. & whitton, b.a. (eds.): biology of blue-green algae. backwell, oxford, 434–472. geologia croatica geologia croatica 61/2–3 378 golubic, s. & campbell, s.e. (1981): biogenically formed aragonite concretions in marine rivularia. – in: monty, c.l.v. (ed.): phanerozoic stromatolites. springer, berlin, 209–229. golubic, s. & fischer, a.f. (1975): ecology of calcareous nodules forming in little conestoga creek near lancaster pennsylvania. – verh. internat. verein. limnol., 19, 2315–2323. golubić, s. & grgasović, t. (2007): plitvice lakes. – in: grgasović, t. & vlahović, i. (eds.): 9th international symposium on fossil algae, field–trip guidebook and abstracts. croatian geological survey, zagreb, 125–134. golubic, s., krumbein, w.e. & schneider, j. (1979): the carbon cycle. – in: trudinger, p.a. & swaine, d.j. (eds.): biogeochemical cycling of mineral-forming elements. elsevier, 29– 45. golubić, s. & marčenko, e. (1958): zur kenntnis der morphologie and taxonomie der gattung oocardium (on morphology and taxonomy of the genus oocardium – desmids). – schweiz. z. hydrol., 20,177–185. golubic, s. & schneider, j. (1979): carbonate dissolution. – in: trudinger, p.a. & swaine, d.j. (eds.): biogeochemical cycling of mineral-forming elements. elsevier, 107–129. golubic, s., violante, c. & d’argenio, b. (1995): travertine biota: a record of seasonal changes. – in: ubertini, l., castelli, f. & bras, r.l. (eds.): climate change and hydrogeological hazards in the mediterranean area. nat. res. council of italy, perugia, 25–30. golubic, s., violante, c., ferreri, v. & d’argenio, b. (1993): algal control and early diagenesis in quaternary travertine formation (rocchetta a volturno, entral apennines). – in: baratolo, f., de castro, p., & parente, m. (eds.): studies on fossil benthic algae. boll. soc. paleontol. ital., spec. vol. 1, 231–247. guo, l. & riding, r. (1999): rapid facies changes in holocene fi ssure ridge hot spring travertines, rapolano terme, italy. – sedimentology, 46, 1145–1158. hägele, d., leinfelder, r., grau, j., burmeister, e.-g. & struck, u. (2006): oncoids from the river alz (southern germany): tiny ecosystems in a phosphorus-limited environment.palaeo., palaeo., palaeo., 237, 378–395. kele, s., korpás, l., demény, a., kovács-pálffy, p., bajnóczi, b. & medzihradszky, z. (2006): paleoenvironmental evaluation of the tata travertine complex (hungary), based on stable isotopic and petrographic studies. – acta geol. hung., 49/1, 1–31. lojen, s., dolenec, t., vokal, b., cukrov, n., mihelčić, g. & papesch, w. (2004): c and o stable isotope variability in recent freshwater carbonates (river krka, croatia). – sedimentology, 51, 361–375. merz, m. (1992): the biology of carbonate precipitation by cyanobacteria. – facies 26, 81–102. merz, m. & zankl, h. (1993): the infl uence of the sheath on carbonate precipitation by cyanobacteria. – in: baratolo f., de castro, p., & parente, m. (eds.): studies on fossil benthic algae. boll. soc. paleontol. ital., spec. vol. 1, 325–331. merz-preiss, m. & riding, r. (1999): cyanobacterial tufa calcifi cation in two freshwater streams: ambient environment, chemical thresholds and biological processes. – sediment. geol., 126, 103–124. obenlüneschloss, j. & schneider, j. (1991): ecology and calcifi cation patterns of rivularia (cyanobacteria). – arch. hydrobiol., 489–502. pavletić, z. & golubić, s. (1956): oocardium stratum nägeli, in den karstgewässern kroatiens. – bull. sci. yugosl., zagreb, 2, 110. pavlović, g., zupanić, j., prohić, e. & tibljaš, d. (2002): impressions of the biota associated with wateralls and cascades from a holocene tufa in the zrmanja river canyon, croatia. – geol. croat., 55/1, 25–37. pedley, h.m. (1990): classifi cation and environmental models of cool freshwater tufas. – sediment. geol., 68, 143–154. pedley, h.m., hill, i., denton, p. & brasington, j. (2000): three-dimensional modeling of a holocene tufa system in the lathkill valley, north derbishire, using ground-penetrating radar. – sedimentology, 47, 721–737. peńa, j.l., sancho, c. & lozano, m.v. (2000): climatic and tectonic signifi cance of late pleistocene and holocene tufa deposits in the mijares river canyon, eastern iberian range, northeast spain. – earth surfa. proc. land., 25, 1403–1417. pentecost, a. (1990): the formation of travertine shrubs: mammoth hot springs, wyoming. – geol. mag., 127, 159–168. pentecost, a. (2005): travertine. springer, berlin, 472 p. plenković-moraj, a., horvatinčić, n. &. primc-habdija, b. (2002): periphyton and its role in tufa deposition at karstic waters (plitvice lakes, croatia). – biologia, 57, 423–431. primc-habdija, b., habdija, i., & plenković-moraj, a. (2001): tufa deposition and periphyton overgrowth as factors affecting the ciliate communit on travertine barriers in different crrent velocity conditions. – hydrobiologia, 457, 87–96. srdoč, d., horvatinčić, n., obelić, b. & sliepčević, a. (1983): radiocarbon dating of tufa in palaeoclimatic studies. – radiocarbon, 25, 421–428. srdoč, d., horvatinčić, n., obelić, b., krajcar, i. & sliepčević, a. (1985): calcite deposition processes in karst waters with special emphasis on the plitvice lakes yugoslavia. – carsus iugoslaviae, 11, 101–204. trichet, j. (1967): essai d’explication du dépôt d’aragonite sur des substrats organiques. – c. r. acad. sci., iii, 265, 1464–1467. turner, e.c. & jones, b. (2005): microscopic calcite dendrites in cold-water tufa: implications for nucleation of micrite and cement. – sedimentology, 52, 1043–1066. wallner, j. (1933): oocardium stratum naeg., eine wichtige tuffbildende alge südbayerns. – planta, 20, 287–293. wallner, j. (1934): über die bedeutung der sog. chironomidentuffe für die messung der järlichen kalkproduktion durch algen. – hedwigia, 74, 176–180. winsborough, b. & golubic, s. (1987): stromatolitic structures of inland waters built by diatoms. – j. phycology, 23, 195–201. zhang, d.d., zhang, y., zhu, a. & cheng, x. (2001): physical mechanisms of river waterfall tufa (travertine) formation. – j. sediment. res., 71, 205–216. zwicker, g. & rubinić, j. (2005): water level fl uctuations as an indicator of the barrier growth dynamics in the plitvice lakes. – rmz – materials and geoenvironment, 52, 161–163. manuscript received may 18, 2008 revised manuscript accepted september 1, 2008 05 babic.indd babić et al.: uplifted pleistocene marine sediments of the central adriatic island of brusnik 223 � ab stra ct the island of brusnik, located in the central adriatic sea, is mainly known for its triassic igneous rocks. however, it also contains pleistocene conglomerates, limestones and neptunian dikes, as well as holocene rock debris, soil, and beach gravels. quaternary sediments unconformably overlie tectonically disturbed triassic basement. the majority of pleistocene limestones, as well as the matrix of the conglomerates, are predominantly bioclastic grainstones and rudstones. gastropod shells in these sediments retain their original aragonite mineralogy, and may also display their original colours. the majority of the conglomerates and limestones originated in lower beachface and shoreface environments. similar sediments have not been identifi ed in the surrounding area and the dinarides in general. some of the pleistocene sediments originated during mis 5e of the last interglacial based on radiometric evidence. the island experienced uplift of about 30m during the middle and late pleistocene and this process probably continued in the postglacial period. the combination of uplift and cyclic sea-level changes is envisaged to have resulted in an overall downstepping pattern of the pleistocene deposits. keywords: central adriatic sea, late pleistocene, brusnik island, conglomerates, bioclastic limestones, tectonic uplift uplifted pleistocene marine sediments of the central adriatic island of brusnik � ljubomir babić1, marta crnjaković2 and yemane asmerom3 1 department of geology, faculty of science, university of zagreb, horvatovac 102a, 10000 zagreb, croatia; (ljubomir.babic@zg.htnet.hr) 2 croatian natural history museum, demetrova 1, 10000 zagreb, croatia; (marta.crnjakovic@hpm.hr) 3 department of earth & planetary sciences, university of new mexico, 2000 yale blvd., ne, albuquerque, nm 87131; (asmerom@unm.edu) doi: 104154/gc.2012.13 geologia croatica 65/2 223–232 10 figs. 1 tab. zagreb 2012 geologia croaticageologia croatica 1. introduction initial data on the features and age of poorly known quaternary sediments of brusnik island are presented, and discussed, regarding the implications for their origin. brusnik island is located within the foreland zone which separates two orogens: the apennines to the sw and the dinarides to the ne (moretti & royden, 1988; bigi et al., 1990; de alteriis, 1995; among others), (figs. 1 and 2). as the foreland area of the central adriatic sea including brusnik island is almost completely covered by sea, only the islands provide an opportunity to study the exposed rocks of this zone. hence, understanding of the brusnik sediments may contribute to the understanding of the geological evolution of this complex and tectonically unstable area. the brusnik sediments are unique as no comparable deposits have been reported from the surrounding areas, including the sea bed and islands, or from the eastern adriatic mainland. we show that besides conglomerates which have been reported previously (hauer, 1867; kišpatić, 1892; martelli, 1904), there are also limestones and limestone dykes, all of which store data regarding the island’s history. initial radiometric dating of the brusnik sediments is also provided. geologia croatica 65/2geologia croatica 224 2. geological setting and previous work the island is about 300x200 m in size, 30 m high, and displays a rocky, rugged topography. it is located in the central adriatic sea (coordinates: 43000’24’’n, 15048’02’’e), in the foreland area separating opposite verging apenninic and dinaridic orogens (figs. 1 and 2) (moretti & royden, 1988; bigi et al., 1990; kruse & royden, 1994; royden et al., 1987). the foreland is a complex unit, which didn't behave uniformly and includes a variety of tectonic structures (royden et al., 1987; doglioni et al., 1994; kru se & royden, 1994; de alteriis, 1995; ar g na ni & frugoni, 1997; grandić et al., 1997, 2001, 2002, 2010; bertotti et al., 1999, 2001; grandić & mar kulin, 2000; oldow et al., 2002; geletti et al., 2008; bennett et al., 2008; korbar, 2009; among others). figure 2 shows the location of brusnik island within the area bounded by the frontal thrusts of the dinarides to the ne, and the outer (sw) margin of the persistent dinaric carbonate platform. the sedimentary succession of the wider area of brusnik consists of permian–lower triassic red beds with evaporites, triassic rift successions which comprise various facies deposited in grabens and on horsts also including evaporites, and thick upper triassic to lower eocene shallow-marine carbonates with evaporites (grandić et al., 1997, 2001, 2002). these carbonates may be overlain by palaeogene, neogene and quaternary clastics. tectonic structures of the area include sw-vergent compressional structures, wrench faults and diapirs (figs. 2 and 3; grandić et al., 1997, 2002, 2010; grandić & markulin, 2000; geletti et al., 2008). tectonic deformation in the area has continued until the present (aljinović et al., 1987; favali et al., 1993; kuk et al., 2000; oldow et al., 2002; pre logović et al., 2003; herak et al., 2005; bennett et al., 2008; see also faults in fig. 2 based on herak et al., 2005). the island of brusnik largely consists of igneous rocks which are regarded to be genetically related to those exposed on the neighbouring islands of vis and jabuka, i.e. to triassic rifting processes (kišpatić, 1892; golub & vrago vić, 1975; mamužić & raffaelli, 1977; balogh et al., 1994; grandić et al., 2001, juračić et al., 2004). besides the igneous rocks, there are peculiar conglomerates containing marine fossils which display their original colours (hauer, 1867, 1882; kišpatić, 1892; martelli, 1904; ma mužić & raffaelli, 1977; crnjaković, 1998). hauer (1867) was the fi rst to report on a conglomerate sample brought to him from brusnik, which consisted of a cobble of an igneous rock, and carbonate matrix with biogenic particles including a bivalve spondylus gaederopus linné. the bivalve partly retained its original reddish colour, and after this author, the conglomerate is of an “offenbar ganz recenten ursprungs” (i.e. obviously of fully recent origin). recent molluscs in conglomerate matrix, as well as the “very recent” age of its origin and subsequent uplift, have also been mentioned by kišpatić (1892) and martelli (1904). more recently, crnjaković (1998) reported on fi ssures in igneous rocks which are fi lled by limestone. 3. laboratory procedure for u-series dating the 234u–230th dating was done at the radiogenic isotope laboratory, the university of new mexico, usa. samples were spiked with a mixed 229th–233u–236u spike. u and th were separated using conventional anion exchange chromatography. u and th isotopes were measured using a ther mo neptune multi-collector inductively coupled plasma mass spectrometer (mc-icpms) which was optimized for u-series analytical work as described by asmerom et al. (2006). 234u was measured on a secondary electron multiplier with high abundance fi lter, while the other isotopes of uranium were measured on faraday cups with amplifi ers that had mixed 1010, 1011 and 1012 ohm resistors for 233u and 236u, 235u and 238u, respectively. mass fractionation was monitored using the 236u/233u ratio, while the sem/faraday gain was set using sample standard bracketing. a similar procedure was used for th isotope measurements. we used an inifigure 1: tectonic sketch showing the adriatic-apulian foreland and neighbouring orogens (from bigi et al., 1990), as well as the location of brusnik island. location of the dinaridic front is after grandić et al. (2001). framed area is shown in fig. 2. babić et al.: uplifted pleistocene marine sediments of the central adriatic island of brusnik geologia croatica 225 figure 2: main structural features of the central adriatic sea. simplifi ed after geletti et al. (2008). note the position of brusnik (asterisk) within a diapirrelated structure. dashed line a–a' indicates the position of the cross-section in fig. 3. for details see text. figure 3: generalized, sw-ne cross-section located close to brusnik island (after grandić et al., 2002). note the character of the „jabuka-komiža salt wall“ (komiža is located in the w part of vis island). not to scale. for location see fig. 2. for further explanation see text. geologia croatica 65/2geologia croatica 226 tial 230th/232th atomic ratio of 4.4x10–6 assuming a source of th with a bulk earth 232th/238u ratio of 3.8. the age errors in table 1 refl ect analytical errors and uncertainties in the value of the initial ratio (± 50%). the laboratory u and th procedural blanks range from 10–40 pg and 5–20 pg, respectively and were not analytically signifi cant. the crm145 u isotope standard was measured with the samples obtaining the conventionally accepted δ234u value of –36.5±0.5‰ (cheng et al., 2000). 4. description of sediments 4.1. general data the most widely encountered sediments on brusnik island are conglomerates (kišpatić, 1892) which occur in small patches covering triassic igneous rocks. they occur from 0 to >25m above sea-level (a.s.l.). small limestone outcrops are observed locally and seem to represent erosional remnants. limestones also fi ll fi ssures in igneous rocks. the sedimentary succession could not be observed clearly due to the isolated character of the smaller outcrops and common surface cover by rock debris. however, there are indications of a close stratigraphic relationship between the conglomerates and limestones. first, the limestone matrix of the conglomerates displays the same features as the majority of the limestones. furthermore, there are transitional types ranging from igneous clast conglomerates without limestone matrix, to conglomerates with a few molluscs, to conglomerates rich in limestone matrix, to limestones rich in igneous clasts, and fi nally, to limestones with only rare igneous clasts. in addition, a small outcrop was observed showing a limestone intercalation (possible erosional remnant) in conglomerates (location 1 in fig. 4). the sediments cover the irregular igneous basement. the nne part of the island includes a rather fl at surface, gently inclined towards the west which could represent a marine terrace. this feature and its relationship to the quaternary sediments deserves further study. aside from the magmatic basement and sediments mentioned above, the island also displays screes, rock debris, soil and coastal gravels. 4.2. conglomerates the conglomerates mostly appear massive, and locally display indistinct bedding (fig. 5). they show a clast-supported fabric, consist of igneous clasts and matrix represented either by smaller igneous clasts with or without minor biogenic particles (fig. 6), or are of bioclastic limestone with rare igneous particles. several specimens of the gastropod cerithium vulgatum bruguiere (based on riedl, 1983), exhibiting their original brown colours have been identifi ed in the conglomerate matrix. the clasts are usually pebble to figure 4: location of outcrops and samples on brusnik island (1–4) mentioned in text and presented in figs. 5–10. the map has been produced by enlargement of the topographic map 1/25000 of the republic of croatia (sheet otok svetac). smaller numbers are heights a.s.l. and depth below sea-level (in metres). crosses in the sea are rocks. dotted area is a recent gravel beach. figure 5: poor bedding in conglomerates. long diameter of the boulder to the right is 40 cm. loc. 2 in fig. 4. about 5m a.s.l. photo by j. vranić. table 1: uranium-series data for a bivalve taken from the limestone matrix of a conglomerate (loc. 3 in fig. 4). 238u (ng/g) 232th (pg/g) 230th/232th activity ratio 230th/238u activity ratio measured δ234u (‰) initial δ234u (‰) uncorrected age (yrs bp) corrected age (yrs bp) 227 ± 1.2 157 ± 42 3513 ± 931 0.793 ± 0.005 140 ± 2 200 ± 3 125162 ± 1568 125146 ± 1568 all errors are absolute 2σ. subsample powder sizes range from 60 to 160 mg. initial 230th/232th atomic ratio used to correct ages is 0.0000044 (activity ratio = 0.81) ± 100%. yrs bp = years before present, where present = ad 2009. babić et al.: uplifted pleistocene marine sediments of the central adriatic island of brusnik geologia croatica 227 cobble-sized, and clasts attaining 0.5 m in diameter are locally present (fig. 5). besides, an exceptionally large, angular clast of igneous rock 4 m in diameter has been observed (close to loc. 1, fig. 4). the conglomerates may consist either of well-rounded clasts, or sub-angular to angular clasts. the limestone matrix closely resembles the limestones which are described below. 4.3. limestones the limestone outcrops hitherto studied in our investigations occur in the northern part of the island (e.g. 4 in fig. 4), and are mainly represented by bioclastic grainstones and rudstones. biogenic constituents include gastropods, bival ves, bryozoans, corallinaceans, and echinoids (crnja ko vić, 1998), as well as rare smaller benthic foraminifera and attached foraminifera. using riedl (1963, 1983) and mi lišić (1991), who described the recent mediterranean and adriatic fauna and fl ora, it was possible to identify gibbula euxinica andrjavski (fig. 7) and bittium reticulatum da figure 6: igneous clast conglomerate containing many fragments of gastropod tests and debris of other fossils. largest gastropod is a cerithium. its preserved portion is 3 cm long. loc. 1 in fig. 4. about 3m a.s.l. photo by j. vranić. figure 7: gastropod gibbula euxinica andrjavski in bioclastic limestone. the test is 8.5 mm wide. loc. 4 in fig. 4. about 11m a.s.l. figure 8: gastropod bittium reticulatum da costa in bioclastic limestone. the test is 3.5 mm wide. loc. 4 in fig. 4. about 11m a.s.l. figure 9: isopachous, acicular cement lining skeletal particles, including a corallinacean (left) and a gastropod (right). note voids which remained empty after cementation. thin section, plane polarised light. loc. 4 in fig. 4. about 11m a.s.l. costa (fig. 8) among several other gastropod species. there was also a limpet, and an oyster. some gastropod specimens display their original colours, as do the echinoid spines. igneous clasts are variably present in the limestones and may be rare to common. after treatment with fiegl's solution (miller, 1988), it was discovered that sections of several gastropod shells displayed their original, aragonite mineralogy. primary voids, both interskelatal and intraskeletal, are lined by isopachous, acicular fringes of calcite (fig. 9), which was identifi ed by staining with alizarin red s, and fiegl's solution (miller, 1988). 4.4. neptunian dykes neptunian dykes in igneous rocks may be observed at several places (fig. 10). the sedimentary fi ll of the fractures either consists of limestone containing gastropods and other biogenic particles, or contains various proportions of biogenic particles and igneous clasts. geologia croatica 65/2geologia croatica 228 5. radiometric data table 1 presents radiometric dating results for a bivalve test extracted from the limestone matrix of the conglomerate found at locality 3, occurring about 9m a.s.l. (fig. 4). 6. discussion 6.1. origin of the sediments the mollusc species identifi ed in the limestones and conglomerates are known to inhabit the shallow bottoms of the present adriatic sea (rield, 1963, 1983; milišić, 1991), while the other organisms observed may also inhabit these environments. the dominant grainstone to rudstone textures of the limestones suggest reworking of skeletal material by agitated waters, and deposition within a shallow-water environment, above fair-weather wave base (crnjaković, 1998). the occurrence of angular igneous clasts in limestones may be related to the vicinity of the rocky coast composed of igneous rocks. the remains of shallow-water organisms in the conglomerates, together with the inferred close relationship between these and the limestones, is interpreted as indicating a similar, shallow marine setting for the conglomerates (see also below). isopachous, acicular calcite fringes indicate a phreatic environment, are typically marine, but may also be precipitated from meteoric waters (tucker & wright, 1990). it is suggested, that a meteoric origin of this cement may be excluded, as fresh waters would have probably caused dissolution of gastropod skeletal aragonite, which is not observed. calcite cements, such as those in the brusnik limestones, are more common in cooler waters in contrast to aragonite cements, as lower temperatures favour calcite precipitation (e.g. burton & walter, 1987). this is in accordance with the current mid-latitude position of brusnik which was also the case during the pleistocene. a “cool-water” character for the brusnik carbonates is also supported by the dominance of gastropods, bivalves, bryozoans, and corallinaceans in the composition of the bioclastic limestones (review in james, 1997). based on the above data and discussion, it is proposed that the origin of clast-supported conglomerates is related to gravels initially formed within a high-energy, wave-dominated beachface, after which most were mixed with carbonate bioclastic material on the beach and in the upper shoreface zone. as shallow-marine biota which produced skeletal material, i.e. carbonate sediment, presumably dominated the adjacent offshore area, small changes in relative sea level, and/or the local wave patterns may have caused shifts in the shoreline which resulted in the alternation of conglomerates and limestones. the commonly occurring isopachous cement, suggests fi nal deposition was below sea-level. some of the igneous clasts may have been brought to the shoreface zone dominated by biogenic production by storm-related processes, becoming a subordinate component of the limestone. the processes discussed above refl ect a close relationship between the relevant environments which resulted in a close association of lithologic types, as well as in the similarity between the limestone matrix of the conglomerates and limestone sediment. conglomerates containing large, angular clasts of igneous rocks may have been deposited in the vicinity of rocky, rugged coasts consisting of igneous rocks. the constituents of the infi lls of open fractures now representing neptunian dikes correspond to the composition of the sediments discussed above, which suggests that the opening of the fractures and their fi lling occurred at the time when conglomerates and limestones were deposited at the relevant locations. 6.2. a tentative quaternary evolution of the island radiometric dating provided an age of 125146 ± 1568 years bp which corresponds to marine isotope stage (mis) 5e. this stage (or substage) is of global importance for the time correlation of sedimentary, tectonic and eustatic processes based on a variety of evidence collected world-wide (chappel & shackleton, 1986; martinson et al., 1987; bard et al., 1990; hooghiemstra & melice, 1994; petit et al., 1999; lyle et al., 2001; lambeck et al., 2002; shackleton et al., 2003; martrat et al., 2004; among others). mis 5e lasted some 18000 years, corresponds to a warm interval, with its warmest part lasting about 12000 years (shackleton et al., 2003) and embraces the measured date above. the conglomerate including the dated bivalve was probably deposited in the upper shoreface, as discussed previously, and was discovered about 9m a.s.l. if the depositional depth is assumed at -1m, the relative rise of the island amounts to about 10m. as the mis 5e sea-level is thought to had been several metres higher than today (chappel & shackleton, 1986; bard et al., 1990; waelbroeck et al., 2002; ferfigure 10: neptunian dyke of limestone seen as a light diagonal stripe in igneous rock. the dyke is up to 13 cm thick. loc. 2 in fig. 4. about 5m a.s.l. photo by d. lacković. babić et al.: uplifted pleistocene marine sediments of the central adriatic island of brusnik geologia croatica 229 ranti et al., 2006), and assuming mis 5e sea-levels at +6m and +3m, respectively, the conglomerate has been uplifted for some 4–7 m in the last 125000 years. this corresponds to an average uplift rate of between 0.032 and 0.056 mm/ year. limited data do not allow for direct generalisation of the above data concerning all pleistocene sediments of brusnik island. however, the patchy occurrences of similar but poorly known facies up to >+25m could suggest that higher parts of the island show older pleistocene sediments presumably deposited during longer and shorter highstand periods and mainly during mis 7, mis 9 and possibly mis 11. it is believed that the oldest deposits occur at the highest portion of the island and that deposition subsequently occurred lower and lower, being younger and younger in the same direction, thus representing an overall downstepping pattern related to overall relative sea-level fall. deposits younger than mis 5e might be those occurring in the lowermost part of the island. this would imply a total pleistocene uplift corresponding approximately to the highest position of pleistocene sediment, which is +25m. patches of pleistocene sediments may be regarded as representing relics which remained after weathering, which started after each highstand depositional period, and increased in extent at lower altitude due to the increasing subaerial surface of the island. poorly recognizable erosional surfaces at the base of some conglomerates, as well as the fl at surface in the nne part of the island may represent remnants of marine terraces related to different relative sea-levels. the rise of brusnik island may be explained by its structural position within an uplifting structure as mentioned above. the uplift may have been accompanied by extensional deformation and earthquakes responsible for the opening of fractures hosting limestone fi lls. another island in the central adriatic sea, velika palagruža, displays certain similarities to brusnik in its geological history, related to its position within an uplift structure which may have resulted either from compression (bertotti et al., 2001) or from diapirism (grandić & markulin, 2000; fig. 2). velika palagruža shows probable marine straths and beach deposits at about +75m and +13m, respectively (korbar et al., 2009). also pelagosite, which otherwise grows on wet rocky shores, has been found at different heights, including 6500 year old examples at +6m (based on u/th dating) (montanari et al., 2007; korbar et al., 2009). these features resulted from a recent uplift of this island. marine straths and beach deposits of velika palagruža may possibly correlate with some parts of the pleistocene evolution of brusnik. however, this does not imply precise synchroneity in the tectonic activity and uplift of the two islands as they belong to different structures located rather far apart (fig. 2). while the brusnik data provide direct outcrop evidence for a recent uplift trend, the areas surrounding the adriatic behaved variously during the relevant time period. for example, the ne and nw adriatic coasts (including islands) are known to have subsided (ferranti et al., 2006; antonioli et al., 2007, with references; surić & juračić, 2010, with references), while the sw adriatic coast displays uplift related to compressional deformation (ferranti et al., 2006; antonioli et al., 2007). this and other differences in the tectonic evolution of the ne and sw adriatic belts may be regarded as refl ecting the different characteristics of apenninic versus dinaric styles of subduction of the adriatic slab (doglioni, 1994; see also discussion by ferranti et al., 2006 and references therein). 6.3. alternative interpretation for some of the brusnik sediments? the data on pleistocene sediments of brusnik island are scattered and only of locally documented character, especially regarding the upper part of the island. in light of this, alternative interpretations of depositional processes for some parts of these sediments may be discussed. given the diffi culties encountered while searching for the type(s) of organisation, fabrics and structures of brusnik sediments, together with the apparent disorder in the distribution of conglomerates, igneous rocks and limestones, possible deposition by exceptionally high storm waves and tsunami waves is appropriate to be included here. such processes include sudden, energetic resedimentation event(s), by which shallow-marine, carbonate particles, and the gravel from the bea ch face and shoreface, are picked up from their original depositional settings, moved, partly mixed together, and displaced to their fi nal depositional sites which may be located onshore, offshore or both. this could occur during one or several, rapid short term depositional events. storm waves may be discounted as it is unlikely that different parts of the subaerial island surface could have been covered in this way. however, a storm-related origin for modest, locally occurring parts of this detritus might be possible. in contrast, some coarse-grained sediments may have been deposited below sea-level by storm-related processes, as discussed above. it is known that tsunamis may result in erosion, and transport of sediments from different environments, displacement of large blocks, and deposition of this detritus both below sea level and/or onshore, up to considerable distances and heights (e.g. shiki & jamazaki, 1996; fujino et al., 2006; bondevik et al., 1997; nichol et al., 2003; scheffers & kelletat, 2005; nanayama & shigeno, 2006). deposition of large clasts and the mixing of igneous clasts and skeletal particles on brusnik bear some similarity to the features resulting from tsunami events. besides, the unique occurrence of these sediments on brusnik makes them “anomalous”, which is a feature characterising tsunami deposits compared to “normal” sediments. alternatively, consideration of a tsunami interpretation should be coupled with the question of whether a tsunami of an appropriate intensity could have occurred in the adriatic sea at the relevant time (middle-late pleistocene). this question is relevant as the present adriatic is a small, semi-closed basin, in contrast to the oceanic domains, where the great majority of tsunamis has been reported including the examples cited above. even during sea-level highstands of the pleistocene, the adriatic was not considerably larger and deeper. available data from different parts of the adriatic, for the geologia croatica 65/2geologia croatica 230 last 2000 years, include tsunamis of different intensities (tinti et al., 2004; paulatto et al., 2007), and although some of them caused heavy damage and human losses, their intensities were below those of tsunamis known from oceanic domains. this is due to the lower seismicity and shallower water of the adriatic basin compared to the oceans (paulatto et al., 2007). however, the brusnik sediments are older than the tsunami records, hence, extrapolating these records to earlier, much longer periods, may not be appropriate. the possibility of large tsunami events, which could have occurred during these earlier times, may be supported by tectonic processes which operated, and are still operating, in the adriatic area. the overall situation includes three surrounding orogens; the dinarides, alps, and apennines, all of which are characterised by tectonic transport towards the adriatic, which is active in both the onshore and offshore zones, especially along the ne and sw adriatic coasts (e.g. bigi et al., 1990; bennett et al., 2008). consequently, numerous tectonic displacement events and earthquakes may be envisaged to have occurred in these areas during the quaternary, beyond the extent of available records. active tectonic boundaries and epicentres located close to brusnik island (aljinović et al., 1987; favali et al., 1993; kuk et al., 2000; oldow et al., 2002; prelogović et al., 2003; herak et al., 2005; bennett et al., 2008) may be relevant for tsunamogenic potential. tsunamogenic processes in the adriatic may have also been related to large-scale, submarine sliding. such processes are known to have occurred in the sw adriatic in the pleistocene, and are taken as an indicator for possible, future large slides and related tsunamis (minisini et al., 2006). the possibility that important tsunami waves did hit brusnik island cannot be excluded based on this discussion. however, onshore deposition by tsunami(s) for a part of brusnik sediments is unlikely. this is because an extremely high tsunami run up would be required to transport large clasts to heights above 20 m (and much more during periods of sea-level lowstands) where they occur at present, and because tsunami deposits have not been observed on neighbouring islands where they would be expected in the case of a large tsunami(s). 7. summary and conclusion aside from the triassic igneous rocks, the island of brusnik, central adriatic, displays pleistocene conglomerates and limestones, as well as holocene rock debris, soil and beach gravels. pleistocene sediments unconformably overlie tectonically disturbed triassic basement igneous rocks, and also occur as neptunian dykes. based on radiometric evidence, some of the pleistocene sediments originated during mis 5e. the conglomerates were predominantly deposited on a highenergy beachface below sea-level, and in the uppermost shoreface, while the limestones accumulated within the same environments and in the shoreface. the limestones, as well as the limestone matrix of the conglomerates are predominantly composed of bioclastic grainstones and rudstones. gastropods occurring in the limestones and conglomerate matrix retain their original skeletal aragonite and may show original colours. cementation in most limestones, as well as the limestone matrix of the conglomerates occurred in phreatic conditions and resulted in acicular, isopachous calcite fringes. the island experienced uplift of about 30m during the middle and late pleistocene and uplift process probably continued in the postglacial period. it is proposed that the combination of uplift and cyclic sea-level changes produced an overall downstepping pattern of middle and late pleistocene deposits. acknowledgement this work is part of the projects “evolutionary changes of the dinarides from subduction to modern adriatic beaches” (no. 119-119115-1159) and “quaternary sediments of the adriatic area” (no. 0183008), both supported by ministry of science, education and sport of the republic of croatia. thoughtful comments by m. tropeano and an anonymous reviewer helped in improving a previous version of the manuscript. important suggestions have also been provided by v. picotti and t. korbar. we thank d. lacković for the help in the fi eldwork, and r. košćal for the artwork. b. lužar-oberiter and j. robson corrected the english text. samples shown in figs. 7 and 8 are stored in the croatian natural history museum, collection of sedimentary rocks, under codes bs-96-3 and bs-96-6, respectively. references aljinović, b., prelogović, e. & skoko, d. (1987): novi podaci o dubinskoj geološkoj građi i seizmotektonskim aktivnim zonama u jugoslaviji.– geol. vjesnik, 40, 255–263. antonioli, f., anzidei, m., lambeck, k., auriemma, r., gaddi, d., furlani, s., orrù, p., solinas, e., gaspari, a., karinja, s., kovačić, v. & surace, l. (2007): sea-level change during the holocene in sardinia and in the northeastern adriatic (central mediterranean sea) from archaeological and geomorphological data.– quaternary sci. rev., 26, 2463–2486. argnani, a. & frugoni, f. (1997): foreland deformation in the central adriatic and its bearing on the evolution of the northern apennines.– ann. geofi s., 40/3, 771–780. asmerom, y., polyak, v., schwieters, j. & bouman, c. (2006): routine high-precision u-th isotope analysis for paleoclimate chronology.– geochim. cosmochim. ac., 70, p. a24. balogh, k., colantoni, p., guerrera, f., majer, v., ravasz-branyai, i., renzulli, a. veneri, f. & alberini, c. (1994): the medium-grained gabbro of the jabuka islet (“scoglio del pomo”, adriatic sea).– giorn. geol., bologna, (3a), 56/2, 13–25. bard, e., hamelin, b. & fairbanks, r.g. (1990): u-th ages obtained by mass spectrometry in corals from barbados: sea level during the past 130.000 years.– nature, 346, 456–458. bennett, r.a., hreinsdóttir, s., buble, g., bašić, t., bačić, ž., marjanović, casale, g., gendaszek, a. & cowan, d. (2008): eocene to present subduction of southern adria mantle lithosphere beneath the dinarides.– geology, 36, 3–6. bertotti, g., casolari, e. & picotti, v. (1999): the gargano promontory: a neogene contractional belt within the adriatic plate.– terra nova, 11, 168–173. babić et al.: uplifted pleistocene marine sediments of the central adriatic island of brusnik geologia croatica 231 bertotti, g., picotti, v., chilovi, c., fantoni, r., merlini, s. & mosconi, a. (2001): neogene to quaternary sedimentary basins in the south adriatic (central mediterranean): foredeeps and lithospheric buckling.– tectonics, 20/5, 771–787. bigi, g., cosentino, d., parotto, t., sartori, r. & scandone, p. (1990): structural model of italy, 1:500,000.– consilio nazionale delle riccerche. roma. burton, e.a. & walter, l.m. (1987): relative precipitation rates of aragonite and mg calcite from sea water: temperature or carbonate ion control?– geology, 15, 111–114. bondevik, s., svendsen, j.i., mangerud, j. (1997): tsunami sedimentary facies deposited by the storegga tsunami in shallow marine basins and lakes.– sedimentology, 44, 1115–1131. chappell, j. & shackleton, n.j. (1986): oxygen isotopes and sea level.– nature, 324, 137–140. cheng, h., edwards, r.l., hoff, j., gallup, c.d., richards, d.a. & asmerom, y. (2000): the half-lives of uranium-234 and thorium-230.– chem. geol., 169, 17–33. crnjaković, m. (1998): volcanoes on the adriatic islands?– croat. nat. history museum, zagreb, 39 p. de alteriis, g. (1995): different foreland basins in italy: examples from the central and southern adriatic sea.– tectonophysics, 252, 349–373. doglioni, c. (1994): foredeeps versus subduction zones.– geology, 22, 271–274. doglioni, c., mongelli, f. & pieri, p. (1994): the puglia uplift (se italy): an "anomaly" in the foreland of the apenninic subduction due to buckling of a thick continental lithosphere.– tectonics, 13/5, 1309–1321. favali, p., funuciello, r., mattietti, g., mele, g. & salvini, f. (1993): an active margin across the adriatic sea (central mediterranean sea).– tectonophysics, 219, 109–117. ferranti, l., antonioli, f., mauz, b., amorosi, a., dai pra, g., mastronuzzi, g., monaco, c., orrù, p., pappalardo, m., radtke, u., renda, p., romano, p., sansò, p. & verrubbi, v. (2006): markers of the last interglacial sea-level high stand along the coast of italy: tectonic implications.– quat. int., 145–146, 30–54. fujino, s., masuda, f., tagomori, s. & matsumoto, d. (2006): structure and depositional processes of a gravelly tsunami deposit in a shallow marine setting: lower cretaceous miyako group, japan.– sed. geol., 187, 127–138. geletti, r., del ben, a., busetti, m., ramella, r. & volpi, v. (2008): gas seeps linked to salt structures in the central adriatic sea.– basin res., 20, 473–487. golub, lj. & vragović, m. (1975): igneous rocks of the dalmatian islands (in croat., engl. summary).– acta geol., 8/4, zagreb, 19–63. grandić, s. & markulin, z. (2000): triassic synrift euxinic basins as a factor of exploration risk in the croatian offshore area.– proceedings of international symposium of petroleum geology, april 22–24, 1999, nafta, spec. issue, 41–50. grandić, s., boromisa-balaš, e. & šušterčić, m. (1997): exploration concept and characteristics of the stratigraphic and structural models of the dinarides in croatian offshore area.– nafta, 48/8–9, 249–266. grandić, s., biancone, m. & samaržija, j. (2001): geophysical and stratigraphic evidence of the triassic rift structuration in the adriatic offshore area.– nafta, 52/12, 383–396. grandić, s., veseli, v. & kolbah, s. (2002): hydrocarbon potential of dugi otok basin in offshore croatia.– nafta, 53/6–7, 215–224. grandić, s., kratković, i. & rusan, i. (2010): hydrocarbon potential assessment of the slope deposits along the sw dinarides carbonate platform edge.– nafta 61/7–8, 325–338. hauer, f.v. (1867): prehnit von comisa auf der insel lissa und eruptivgesteine aus dalmatien.– verhandl. geol. reichsanst., 1867/4, 89–91. hauer, f.v. (1882): der scoglio brusnik bei st. andrea in dalmatien.– verhandl. geol. reichsanst., 1882/5, 75–77. herak, d., herak, m., prelogovic, e., markusic, s. & mar kulin, z., 2005 jabuka island (central adriatic sea) earthquakes of 2003.– tectonophysics, 398, 167–180. hooghiemstra, h. & melice, j.l. (1994): pleistocene evolution of orbital periodicities in the high-resolution pollen record funza i, eastern cordillera, columbia.– sp. publ. int. 19, 117–126. james, n. (1997): the cool-water carbonate depositional realm.– in: james. n.p. & clarke, j.a.d. (eds.): cool-water carbonates. sepm sp. publ., 56, 1–20. juračić, m., novosel, a., tibljaš, d. & balen, d. 2004: jabuka shoal, a new location with igneous rocks in the adriatic sea.– geol. croat., 57, 81–85. kišpatić, m. (1892): eruptivno kamenje u dalmaciji.– rad jugosl. akad., 111, zagreb, 158–190. korbar, t. (2009): orogenic evolution of the external dinarides in the ne adriatic region: a model constrained by tectonostratigraphy of upper cretaceous to paleogene carbonates.– earth-sci. rev., 96/4, 296–312. korbar, t., montanari, a., koch, g., mariani, s., depaolo, d., turchyn, a.v., miknić, m. & tari, v. (2009): geologic reconnaissance of the island of velika palagruža (central adriatic, croatia).– geol. croat., 62/2, 75–94. kruse, s.e. & royden, l.h. (1994): bending and unbending of an elastic lithosphere: the cenozoic history of the apennine and dinaride foredeep basins.– tectonics, 13/2, 278–302. kuk, v., pelogović, e. & dragičević, i. (2000): seismotectonically active zones in the dinarides.– geol. croat., 53/2, 295–303. lambeck, k., esat, t.m. & potter, e-k. (2002): links between climate and sea levels for the past three million years.– in: ziemelis, k. (ed.): nature insight – climate and water. nature, 419, 199–206. lyle, m., heusser, l., herbert, t., mix, a. & barron, j. (2001): interglacial theme and variations: 500 k.y. of orbital forcing and associated responses from the terrestrial and marine biosphere, u.s. pacifi c northwest.– geology, 29, 1115–1118. mamužić, p. & raffaelli, p. (1977): geology of the sheet svetac (in croat., engl. summary).– in: borović, i., marinčić, s., majcen, ž., magaš, n., raffaelli, p. & mamužić, p.: explanatory notes for sheets vis, jelsa, biševo, svetac, and jabuka. basic geological map of yugoslavia, 1:100000. institute of geological research, zagreb. federal geological institute, beograd, 49–60. martelli, a. (1904): osservazioni geographico-physiche e geologiche sull'isola di lissa (i).– b. soc. geol. ital., 4/5, 530–550. martinson, d.g., pisias, n.g., hayas, j.d., imbrie, j., moore, t.c. jr. & shackleton, n.j. (1987): age dating and the orbital theory of the ice ages: development of a high-resolution 0 to 300,000-year chronostratigraphy.– quat. res., 27, 1–29. martrat, b., grimalt, j.o., lopez-martinez, c., cacho, i., sierro, f.j., flores, j.a., zahn, r., canals, m., curtis, j.h. & hodell, d.a. (2004): abrupt temperature changes in the western mediterranean over past 250,000 years.– science, 306, 1762–1764. milišić, n. (1991): školjke i puževi jadrana.– logos, split, 302 p. miller, j. (1988): microscopical techniques: i. slices, slides, stains, and peels.– in: tucker, m. (ed.): tech. in sedimentology, blackwell, oxford, 86–107. minisini, d., trincardi, f. & asioli, a. (2006): evidence of slope instability in the southwestern adriatic margin.– nat. hazards earth sist. sci., 6, 1–20. geologia croatica 65/2geologia croatica 232 montanari, a., bice, d., druschel, g., mariani, s., marshall, c., olcott, a., sharp, w., tigue, t. & vucetic, m. (2007): rediscovering pelagosite: a mediterranean "microstromatolite" recording recent climate cycles.– geoph. res. abstracts, 9, 01555, 2007.sref-id: 1607-7962/gra/egu2007-a-01555. european geoscience union. moretti, i. & royden, l. (1988): defl ection, gravity anomalies and tectonics of doubly subducted continental lithosphere: adriatic and ionian seas.– tectonics, 7, 875–893. nanayama, f. & shigeno, s. (2006): infl ow and outfl ow facies from the 1993 tsunami in southwest hokkaido.– sed. geol., 127–158. nichol, s.l., lian, o.b. & carter, c.h. (2003): sheet-gravel evidence for a late holocene tsunami run-up on beach dunes, great barrier island, new zealand.– sed. geol., 155, 129–145. oldow, j.s., ferranti, l., lewis, d.s., campbell, j.k., d'argenio, b., catalano, r., pappone, g., carmignani, l., conti, p. & aiken, c.l.v. (2002): active fragmentation of adria, the north african promontory, central mediterranean orogen.– geology, 30, 779–782. paulatto, m., pinat, t. & romanelli, f. (2007): tsunami hazard scenarios in the adriatic sea domain.– nat. hazards earth sist. sci., 7, 309–325. petit, j.r., jouzel, j., raynaud, d., barkov, n.j., barnola, j.-m., basile, i., bender, m., chappellaz, j., davis, m., delaygue, g., delmotte, m., kotlyakov, v.m., legrand, m., lipenkov, v.y., lorius, c., pépin, l., ritz, c., saltzman, e. & stievenrd, m. 1999): climate and atmospheric history of the past 420,000 years from the vostok ice core, antractica.– nature, 399/3, 429–436. prelogović, e., pribičević, b., ivković, ž., dragičević, i., buljan, r. & tomljenović, b. (2003): recent structural fabric of the dinarides and tectonically active zones important for petroleum-geological exploration in croatia.– nafta, 55, 155–161. riedl, r. (1963): fauna und flora der adria.– paul paray, hamburg, 640 p. riedl, r. (1983): fauna und flora der mittelmeeres. 3. ed.– paul paray, hamburg, 836 p. royden, l., patacca, e. & scandone, p. (1987): segmentation and confi guration of subducted lithosphere in italy: an important control on thrust-belt and foredeep-basin evolution.– geology, 15, 714–717. scheffers, a. & kelletat, d. (2005): tsunami relics on the coastal landscape west of lisbon, portugal.– sci. tsun. hazards, 23, 3–16. shackleton, n.j., sánchez-goñi, m.a. pailler, d. & lancelot, y. (2003): marine isotope substage 5e and the eemian interglacial.– global planet. change, 36, 151–155. shiki, t. & jamazaki, t. (1996): tsunami-induced conglomerates in miocene upper bathyal deposits, chita peninsula, central japan.– sed. geol., 104, 175–188. surić, m. & juračić, m. (2010): late pleistocene-holocene environmental changes – records from submerged speleothems along the eastern adriatic coast (croatia).– geol. croat., 63/2, 155–169. tinti, s., maramai, a. & graziani, l. (2004): the new catalogue of italian tsunamis.– nat. hazards, 33, 439–465. http://www. ingv.it//italiantsunamis/tsun.html tucker, m.e. & wright, v.p. 1990: carbonate sedimentology.– blackwell, oxford, 482 p. waelbroeck, c., labeyrie, l., michel, e., duplessy, j.c., mcmanus, j.f., lambeck, k., balbon, e. & labracherie, m. (2002): sea-level and deep water temperature changes derived from benthic foraminifera isotopic records.– quaternary sci. rev., 21, 295–305. manuscript received september 28, 2009 revised manuscript accepted april 25, 2012 available online june 29, 2012 1. introduction the miocene complex of the poæeπka mt. (figs. 1 and 2) represents a part of the sw marginal zone of the pannonian basin (fig. 3), as part of central paratethys. formation of the pannonian basin commenced in the early and middle miocene, due to the collision of the african (apulian) and european plates. the basin is located along the concave side of the a-type subduction arc, and is surrounded by the alps, carpathians and dinarides (horváth & royden, 1981; horváth, 1984, 1993; royden et al., 1982, 1983a, b; royden, 1988; csontos et al., 1992). it is superimposed on the older palaeogene basinal complex as the result of the back-arc extension, and during the miocene pliocene period it existed as one of many lower miocene alluvial deposits of the poæeπka mt. (pannonian basin, northern croatia): cycles, megacycles and tectonic implications davor paveli∆ and marijan kova»i∆ mediterranean back-arc basins (stegena et al., 1975; horváth & royden, 1981; royden et al., 1982; tari et al., 1992a, b). according to these aforementioned authors, deposition in the entire pannonian basin was strongly influenced by extensional tectonics. on the basis of its depositional history, paveli∆ (1998) attributed early miocene extensional processes in the area between the sava and drava rivers, to the formation of a rift-type basin generated by passive continental rifting (early miocene north croatian basin). up to the present there have been no published data on the sedimentology of the lower miocene (?ottnangian) fresh-water deposits of poæeπka mt. some characteristics of these deposits can be found in former regional works (©parica et al., 1980; ©parica & buzaljko, 1984), where they are divided into lower and upper part, and their origin attributed to disintegration of the basement caused by intense tectonic activity. in the lower part of the succession coarse-grained clastics are common: frequent alternations of conglomerates, breccia and sandstone, as well as gravel and sand. this level is characterized by a lack of fossils, and the deposits are interpreted as “prolluvial” in origin. the upper part of these sections is composed of intercalations of marl, gravel, sand, clay and coal. this level is characterised by a fossil fauna typical for fresh-water environments, which was interpreted as lacustrine by kochansky-devidé (1978) and kochanskydevidé & sli©kovi∆ (1978). fresh-water deposits are probably conformably overlain by karpatian marls, sands and gravel of marine origin (©parica et al., 1979), as a consequence of the transgression that affected vast areas of the central paratethys (rögl & steininger, 1983). the entire lower miocene sedimentary complex of poæeπka mt. is situated near the sava fault, which was determined as a dextral strike-slip fault (horváth & royden, 1981; jami»i∆, 1988, 1995; royden, 1988; rumpler & horváth, 1988; bergerat, 1989; horváth, 1993 fig. 3). considerable lithological variability of the alluvial deposits, their genetic relationship to tectonic activity, as well as their proximity to the sava fault, made it neccessary to undertake facies analysis of these deposits. results indicate the depositional style which enables recognition of the vertical trends and allows interpretation of autocyclic and allocyclic control on sedimentation. g eol . croat. 52/1 67 76 7 figs. 1 tab. zagreb 1999 key words: braided alluvial fan, synsedimentary tectonics, sava fault, early miocene, pannonian basin, croatia. institute of geology, sachsova 2, p.o.box 268, hr-10000 zagreb, croatia. abstract in the area of the present poæeπka mt. braided alluvial fans were formed during the early miocene above the subsiding cretaceouspalaeogene basement. due to autocyclic processes, i.e. lateral migration of flows due to vertical aggradation of longitudinal bars, or migration of the main trench, small-scale fining-upward cycles were formed. the complete succession of the alluvial deposits is composed of two fining-upward megacycles, which are the consequence of allocyclic influences, i.e. the pulsating character of synsedimentary tectonics. megacycles were developed parallel to backstepping of the front of the fault scarp towards the mountain massif, caused by normal faulting along the active margin of an extensional basin. this kind of depositional style indicates that the sava fault operated as a normal fault at the beginning of its life during the early miocene, probably the ottnangian. 68 geologia croatica 52/1 2. geological setting and stratigraphy lower miocene fresh-water deposits cover vast areas in northern croatia, both on the surface and in the subsurface (paveli∆, 1998). on the surface they are most widespread in the central and nw part of poæeπka mt. (fig. 2). the age of these deposits is not precisely defined by chronostratigraphic methods. in their upper part, kochansky-devidé (1978) determined endemic species of a lacustrine macrofauna. based on superposition and correlation with some localities in northern croatia and northern bosnia, these deposits are thought to be ottnangian to karpatian in age. ©parica et al. (1980) and ©parica & buzaljko (1984) considered these deposits as “lower helvetian”, because of their gradual transition into the clastic sediments, the age of which is determined by foraminiferal assemblages as being of “upper helvetian”, i.e. marine karpatian. later, ©parica & pami∆ (1986) attributed an ottnangian age to the entire fresh-water complex, but without new stratigraphic data. the lower miocene sedimentary complex of poæeπka mt. (fig. 2) unconformably overlies the pre-miocene basement (©parica et al., 1979; halami∆ et al., 1990), which in a geotectonic sense represents a part of the supradinaric (herak, 1986), i.e. northern margin of the inner dinarides (herak et al., 1990; ©iki∆, 1995). the miocene basement is composed of upper cretaceous (©parica et al., 1979, 1980) and probably palaeogene rocks (halami∆ et al., 1993). the upper cretaceous deposits comprise limestones and clastic rocks (©parica et al., 1979, 1980), although a part of the clastic sequence could be oligocene in age (halami∆ et al., 1993). according to pami∆ & ©parica (1983), ©parica & pami∆ (1986) and pami∆ et al. (1990) the volcano-sedimentary complex is also of late cretaceous age, while belak et al. (1998) indicate the possibility of a continuation of the volcanic activity into the palaeogene. basement rocks were intensely folded during the laramian phase of the alpine orogeny, as well as during the post-cretaceous tectonic activity (jami»i∆ et al., 1985). after the early miocene, deposition continued into the middle miocene. during the badenian, marine clastics and carbonates were deposited, while sarmatian clastics and carbonates were deposited in brackish environments (©parica et al., 1980; ©parica & buzaljko, 1984). the transition from the early to middle miocene is gradual, although pannonian deposits sporadically transgressively overlie older rocks (©parica et al., 1980; ©parica & buzaljko, 1984). according to these authors pannonian carbonates and marls were deposited in brackish environments, while occurrences of clastic rocks are infrequent. during the pontian, marls and sands were also deposited in brackish, and later in fresh-water environments. they are conformably overlain by fresh-water clastic deposits of pliocene age (©parica et al., 1980; ©parica & buzaljko, 1984). 3. facies characteristics of the lower miocene alluvial deposits are well illustrated in two geological sections (fig. 4 and table 1), measured in the central part of poæeπka mt. (fig. 2). their superposition is clearly defined by detailed geological mapping. the depositional sequence measured at poæeπka gora i (pg i) is 109 m thick, and at the poæeπka gora ii (pg ii) its thickness is 50 m (fig. 4). the main characteristics of these deposits are as follows: a domination of clastics over carbonates and fig. 1 location map of the study area. fig. 2 geological sketch-map of the part of poæeπka mt. (from ©parica et al., 1979) with locations of sections pg-i and pgii. legend: 1) quaternary; 2) pontian; 3) sarmatian, pannonian; 4) badenian; 5) karpatian; 6) ottnangian; 7) upper cretaceous; 8) normal boundary; 9) transgressive boundary; 10) fault. coarse-grained over fine-grained deposits; conspicuous variations in grain size; very rapid lateral and vertical facies alternations; occurrences of red beds; changes in composition; and lack of fauna. during geological mapping it has been determined that the investigated deposits pass upward into massive unfossiliferous silts, with rare lenses of gravel exhibiting low-angle crossbedding and massive fabric. these deposits are overlain by lacustrine fossiliferous silts and marls with interbeds of gravel, sand, clay and coal lenses (©parica et al., 1980). deposits in the measured sections were grouped into nine facies units: 1) massive matrix-supported conglomerates (gmu plastic debris flow), 2) massive 69paveliê & kovaëiê: lower miocene alluvial deposits of the poæeπka mt. ... fig. 3 index map of the pannonian basin and surrounding mountain systems. the position of the sava and drava faults has been added (simplified after horváth, 1993). code facies position sediment structure and interpretation in sections main characteristics gmu massive conglomerates, pg-i: 14-86 m no grading, reddish colour, plastic debris flow matrix-supported pg-ii: 14-17 m fragments up to 10 cm long massive conglomerates, inverse to normal grading, gmi matrix-supported, rare pg-i: 23-94 m reddish colour, fragments pseudoplastic debris flow clast-supported up to 40 cm long bcn massive breccia, pg-i: 0-5 m and crude normal grading, rock-fall clast-supported 99-109 m fragments up to 70 cm long crude normal grading, imbrication gc massive conglomerates, pg-i: 23-95 m a(t) b(i), low-angle cross-bedding; main fan-trench; clast-supported pg-ii: 0-50 m no grading; fragments up to longitudinal bar 200 cm long ge pebble to granule pg-i: 13-97 m lenses stream flows; conglomerates pg-ii: 2-49 m crevasse channels sh fineto coarse-grained pg-i: 15. and 99. m horizontal lamination upper flow regime sandstones pg-ii: 1-49 m f1 silt pg-i: 18-96 m massive, brown colour flood plain; abandoned channel f2 silt, scattered granules, pg-i: 11-99 m indications of a soil-forming palaeosol rare calcrete pg-ii: 7-49 m processes, reddish colour p calcrete pg-i: 14. m and horizontal lamination palaeosol 96-98 m table 1 facies, their main characteristics and interpretation. codes are modified after miall (1978a) and waresback & turbeville (1990). 70 geologia croatica 52/1 matrixto clast-supported conglomerates (gmi pseudoplastic debris flow), 3) massive clast-supported breccia (bcn rock-fall), 4) massive clast-supported conglomerates (gc main fan-trench, longitudinal bar, channels), 5) lenses of pebble to granule conglomerates (ge stream flows), 6) horizontally laminated sandstones (sh upper flow regime), 7) massive silts (f1 flood plain), 8) modified silts (f2 palaeosol), and 9) calcrete (p palaeosol). these facies were described in detail and interpreted by paveli∆ (1998). their main lithological characteristics, position in the sequence and interpretation are presented in table 1. the vertical succession of the deposits is dominantly composed of small fining-upward cycles (fig. 4). these cycles are recognised within a general, gradual decrease in grain-size upwards, which is followed by a thinning of beds composed of coarse-grained sediments and corresponding thickening of beds composed of fine-grained sediments. generally, fining-upward cycles begin with deposits of the river bar (gc), commonly formed on the channel lag, followed by deposits of the bar cover (sh), and are capped by sediments deposited on the flood-plain (f1, f2 and p), shallow channels on the bar or crevasse channels (ge) (fig. 4). conglomerfig. 4 measured sections pg-i and pg-ii with typical fining-upward cycles and megacycles. for explanation of the facies codes see table 1. 71paveliê & kovaëiê: lower miocene alluvial deposits of the poæeπka mt. ... ates deposited by gravitational mechanisms (gmu and gmi) occur in various parts of the cycles, from the basal and middle to the upper part, irrespective of the trend. cycle thicknesses range from 0.5-7.8 m, most frequently from 2-4 m. in some places cycles are not developed, e.g. in a 14.5 m thick complex unit of conglomerates of facies gc (fig. 4, pg-i section from 2438.5 m), which comprises the largest fragments in the entire succession. in addition, fining-upward cycles were not found in the basal part of the pg-i section, and at some other places. 4. palaeotransport flow directions are reconstructed by measurements of the dip direction of imbricated platy fragments in coarse-grained facies (gc, ge and bcn). a total of 676 fragment orientations were measured 438 in the section pg-i, and 238 in the section pg-ii (fig. 5). in the entire succession a very wide dispersion of flow orientation data was recorded. the results indicate a general palaeotransport direction towards the north, with a weak ne tendency in deposits of the pgii section (fig. 5b). 5. facies associations and interpretation two facies associations were separated in the investigated deposits. the facies association a is composed of facies bcn, gc, ge, f1, f2 and p. this facies association occurs in the basal and upper part of section pg-i (0-40 m and 99-109 m fig. 4). the facies association b is composed of facies gmu, gmi, gc, ge, sh, f1, f2 and p. this association comprises the middle part of section pg-i (40-99 m) and the entire succession of the pg-ii section (fig. 4). the association of sediments deposited by debris flows mechanisms (facies gmu, gmi and bcn) with deposits of traction currents (facies gc, ge and sh) and sediments of flood-plains (f1, f2 and p) indicates deposition in alluvial environments, relatively close to the source area, probably in the alluvial fan (bull, 1972; rust, 1978; heward, 1978; miall, 1978a, 1990, 1996; nemec & postma, 1993; stanistreet & mccarthy, 1993). previously these deposits were interpreted as “prolluvial” (©parica et al., 1980). according to the subdivision of alluvial fans, which was on the basis of predominant depositional mechanisms as proposed by stanistreet & mccarthy (1993), this fan could be assigned to the mixed form between the debris flow dominated alluvial fan and the braided alluvial fan model. considering the predominance of sediments deposited by traction in the succession, the poæeπka mt. fans seem closer to the braided alluvial fan. the fan evolved in a semi-arid climate, as indicated by the associated occurrence of calcretes, common gravitational flows, red pigmentation and lack of coal (for discussion of climate related characteristics of alluvial fans see miall, 1996). sediments of the facies association a were deposited in the proximal part of the braided alluvial fan. this interpretation is testified by the occurrence of rock-fall breccia (bcn), and very large fragments, up to 200 cm in size, in the complex facies unit gc (fig. 4, pg-i section from 24-38.5 m). sediments of the facies association b were deposited in the medial part of the braided alluvial fan, as indicated by the predominance of sediments deposited by traction currents (facies gc and ge), over debris flows deposits (facies gmi and gmu), as well as relatively thicker units composed of finegrained sediments, which were exposed to pedogenic processes. the erosional base of sediments comprising the small fining-upward cycles suggests an abrupt incision by strong currents into the flood-plain deposits. sediments of the gc facies in the basal part of the cycle indicate formation on longitudinal bars. the remainder of the depositional sequence (excluding deposits of gmu and gmi facies), which is composed of finegrained deposits of the f1, f2 or p facies in the top of the cycle, can be interpreted as a result of vertical bar aggradation, and subsequent formation of the floodplain. vertical aggradation could have been stopped when the bar rose (due to the large input of the material) above the highest water level. in the investigated deposits there are no traces of the lateral accretion of the macroforms, thus meandering, with gradual filling and abandonment of channels can be excluded. therefore, fining-upward cycles could indicate lateral shifts of flows caused by the formation of bars. however, flow shifts may also be caused by lateral shift of the main trench located in the proximal part of the fan (cf. massari et al., 1993). the occurrence of sediments deposited by gravitational flows (gmu and gmi) within these cycles can be explained by individual events within the fan (sensu heward, 1978). they were initiated locally, from the fan top or associated slopes, perhaps during rain as a consequence of a sudden destabifig. 5 rose diagram measured as dip of imbrication shows palaeotransport from the south to the north in deposits of the pg-i section (a), and from the south-west to the north-east in deposits of the pg-ii section (b). a b 72 geologia croatica 52/1 lization of the undercut channel walls, or by a different cause of destabilization of previously deposited, unconsolidated material, similar to the examples presented by larsen & steel (1978) and nemec & postma (1993). this type of cycle is typical for braided alluvial fans as a consequence of the autocyclic process on the surface (heward, 1978; miall, 1996). it occurs in the second phase of fan development, when backfilling of the main fan-trench and flow dispersion commence (decelles et al., 1991) (fig. 6). a 14 m thick conglomerate unit of facies gc indicates very strong flows and long-lasting vertical aggradation. conglomerates of this facies are located between the rock-fall breccia (bcn) and deposits constituting fining-upward cycles formed in the phase of flow dispersion. therefore conglomerates of the aforementioned unit could belong to the main trench, formed in the first phase of fan development (“entrenchment”, after decelles et al., 1991). 6. megacycles and tectonics the measured succession can be divided into two fining-upward megacycles (fig. 4). the beginning of the megacycle is marked by facies of normally graded breccia (bcn fig. 4, pg-i section, basal and top part). the fining-upward trend in the first megacycle (fig. 4, pg-i section except the top) is expressed by a general decrease in the fragment size in coarse-grained deposits and the occurrence of thick calcretes near the top of the cycle (fig. 4, pg-i section, 96.5-98 m), followed by gradual decreasing of the conglomerate unit thickness. in the second megacycle this trend is indicated by more common occurrences and thickening of facies unit f2 in respect to facies gc and ge towards the upper part of the succession (fig. 4, top of the pg-i section and pgii section). fining-upward megacycles indicate the gradual migration of the source area away from the environment of deposition. this succession could be attributed to the backstepping of the fault scarp towards the source mountain massif (cf. heward, 1978), or gradual lowering of the relief by normal faulting along the active margin of the extensional basin (cf. miall, 1978b). the initial deposition of rock-fall breccias in the base of megacycles indicate the very high intensity of tectonic activity, and trapping of coarse-grained clas tics near the steep slopes in the proximity of the source area (sensu blair, 1987; blair & bilodeau, 1988; heller & paola, 1992). a relative decrease in tectonic activity is shown by the development of flows in the mountain massif, and the formation of the alluvial fan at the margin of the basin (sensu blair, 1987; blair & bilodeau, 1988; heller & paola, 1992). these processes are in congruence with the change in sediment composition recorded in the pg-ii section with respect to the pg-i section. namely, the main characteristics of the sediment composition suggest that the source area of deposits observed in the pgi section was predominantly composed of metamorphic rocks, while deposits found in the pg-ii section mostly originated by erosion of sedimentary and volcanic rocks. according to the available data (©parica et al., 1980; halami∆ et al., 1990; halami∆ et al., 1993; pami∆ et al., 1990; belak et al., 1998), the basement of poæeπka mt. below the miocene deposits is composed of sedimentary and volcanic rocks of late cretaceous and palaeogene age. therefore, it may be concluded that a source area for deposits of the pg-i section, according to the reconstructed palaeotransport directions, was probably located south of the present poæeπka mt. the change in sediment composition in the pg-ii section indicates a shift of the source area, which may have been caused by tectonic events along the fig. 6 a model of the poæeπka mt. braided alluvial fan in the phase of dispersed flow. only facies of coarse-grained deposits are presented: gmu and gmi facies are locally initiated debris-flows, bcn facies represents rock-fall breccias, and gc facies indicates channels and longitudinal bars. 73paveliê & kovaëiê: lower miocene alluvial deposits of the poæeπka mt. ... basin margin (cf. lawton, 1986). normal faulting in the period of enhanced tectonic activity, resulted in gradual subsidence of the block which represented the source area for formation of deposits recorded in the pg-i section (fig. 7). in this way the other block, composed of different rocks, became the highest. in the period of weaker tectonic activity between two megacycles a newly exposed block was eroded, which resulted in rapid progradation. reactivation of tectonics resulted in intensified normal faulting and the successive lowering of the relief, and therefore sediments deposited in the fan had the composition reflecting a new eroded block (fig. 7). the boundary between these megacycles could be compared to a boundary surface of the 5th order, and represents a consequence of allocyclic processes (sensu miall, 1996). composition of the alluvial deposits of the poæeπka mt. and reconstructed palaeotransport directions could indicate the now uplifted core of the motajica mt. as the source area (fig. 1), which is composed of granites, metamorphic and clastic rocks (pami∆ & prohi∆, 1987). if the geological position of the alluvial deposits of poæeπka mt. is related to the defined zone of the sava fault, which is characterised as a dextral strike-slip fault (horváth & royden, 1981; jami»i∆, 1988, 1995; royden, 1988; rumpler & horváth, 1988; bergerat, 1989; horváth, 1993 fig. 3), development of the fan would primarily depend on its lateral shift along the fault, as well as the systematic progradation of the fan itself (steel, 1988). in the example presented by steel (1988), contemporaneous lateral shift and progradation of the fan will result in the likely possibility of the formation of predominantly coarsening-upward or coarsening-fining-upward cycles and megacycles. in the case of the poæeπka mt. alluvial deposits, these types of cycles and megacycles are not developed deposits are composed of fining-upward cycles and megacycles (fig. 4). formation of the fining-upward megacycles is interpreted as the result of the normal faulting along the active margin of the subsiding basin (fig. 7), indicating that the sava fault operated as a normal fault in the early miocene. this type of faulting in extensional geotectonic units is characteristic for the rift-type basins (blair & bilodeau, 1988; miall, 1990; frostick & steel, 1993; leeder, 1995). 7. conclusion 1) in the early miocene (?ottnangian), a braided alluvial fan developed in the area of poæeπka mt., as represented by deposits of main trench, braided channels, longitudinal bars and the flood-plain. the fan evolved in a semi-arid climate, and flows were oriented generally towards the north. 2) autocyclic processes, such as the lateral migration of flows due to the vertical aggradation of longitudinal gravely bars or a shift of the main trench of the fan, produced small-scale fining-upward cycles. 3) the entire measured succession of deposits is composed of two fining-upward megacycles, which are the consequence of allocyclic control, i.e. the pulsatory character of the synsedimentary tectonics. megacycles were formed by backstepping of the fault scarp towards the source mountain massif, caused by normal faulting along the active margin of the extensional basin. 4) the determined depositional style suggests that the sava fault operated as a normal fault at the beginning of its formation during the early miocene (?ottnangian). acknowledgements this paper represents a part of the phd thesis of davor paveliê, which was undertaken under the mentorship of professor joæica zupani» (zagreb), to which the authors are very grateful for very useful comments and suggestions. we would like to thank the reviewers, professor josip t i © l j a r (zagreb) and professor orsolya s z t a n o (budapest) for their careful revision of the manuscript. these investigations represent a part of the project: geological map of the republic of croatia, scale 1:50.000, financed by the ministry of science and technology of the republic of croatia. 8. references belak, m., halami∆, j., marchig, v. & tiblja©, d. (1998): upper cretaceous palaeogene tholeiitic basalts of the southern margin of the pannonian basin: poæeπka gora mt. (croatia).geol. croatica, 51/2, 163-174. bergerat, f. (1989): from pull-apart to the rifting process: the formation of the pannonian basin.tectonophysics, 157, 271-280. fig. 7 backstepping of the poæeπka mt. braided alluvial fans caused by successive normal faulting. the stratigraphic position of the compiled sections pg-i and pg-ii is marked by thick black line. 74 geologia croatica 52/1 blair, t.c. (1987): tectonic and hydrologic controls on cyclic alluvial fan, fluvial and lacustrine riftbasin, jurassic-lowermost cretaceous todos santos formation, chiapas, mexico.jour. sedim. petrol., 57, 845-862. blair, t.c. & bilodeau, w.l. (1988): development of tectonic cyclothemes in rift, pull-apart, and foreland basins: sedimentary response to episodic tectonism.geology, 16, 517-520. bull, w.b. (1972): recognition of alluvial-fan deposits in the stratigraphic record.in: rigby, k.j. & h a m b l i n , w.k. (e d s.): recognition of ancient sedimentary environments. soc. econ. petrol. miner. spec. publs., 16, 68-83. csontos, l., nagymarosy, a., horváth, f. & kovác, m. (1992): tertiary evolution of the intra-carpathian area: a model.tectonophysics, 208, 221-241. decelles, p.g., gray, m.b., ridgway, k.d., cole, r.b., pivnik, d.a., pequera, n. & srivastava, p. (1991): controls on synorogenic alluvial-fan architecture, beartooth conglomerate (paleocene), wyoming and montana.sedimentology, 38, 567-590. frostick, l.e. & steel, r.j. (1993): sedimentation in divergent plate-margin basins.in: f r ostick, l.e. & steel, r.j. (eds.): tectonic controls and signatures in sedimentary successions. int. assoc. sed. spec. publs., 20, 111-128. halami∆, j., belak, m. & jami»i∆, d. (1990): geoloπko-petrografski prikaz baziënih vulkanskih stijena poæeπke gore (slavonija, hrvatska).12. kongres na geolozi na jugoslavija, 2, 456-465, ohrid. halami∆, j., belak, m. & paveli∆, d. (1993): the sedimentological significance and stratigraphic position of coarse-grained red beds (?oligocene) of the northwestern margin of mt. poæeπka gora (north croatia).geol. croatica, 46/1, 137-143. heller, p.l. & paola, c. (1992): the large-scale dynamics of grain-size variation in alluvial basins, 2: application to syntectonic conglomerate.basin research, 4, 91-102. herak, m. (1986): a new concept of geotectonics of the dinarides.acta geol., 16/1, 1-42, zagreb. herak, m., jami»i∆, d., ©imuni∆, a. & bukovac, j. (1990): the northern boundary of the dinarides.acta geol., 20/1, 5-27, zagreb. heward, a.p. (1978): alluvial fan sequence and megasequence models: with example from westphalian d stephanian b coalfields, northern spain.in: m i a l l, a.d. (ed.): fluvial sedimentology. can. soc. petrol. geol. mem., 5, 669-702, calgary. horváth, f. (1984): neotectonics of the pannonian basin and the surrounding mountain belts: alps, carpathians and dinarides.annal. geophys., 2, 147-154. horváth, f. (1993): towards a mechanical model for the formation of the pannonian basin.tectonophysics, 226, 333-357. horváth, f. & royden, l. (1981): mechanism for the formation of the intra-carpathian basins: a rewiev.earth sci. rev., 3-4, 307-316. jami»i∆, d. (1988): strukturni sklop slavonskih planina (krndija, papuk i psunj).unpublished phd thesis, university of zagreb, 152 p. jami»i∆, d. (1995): the role of sinistral strike-slip faults in the formation of the structural fabric of the slavonian mts. (eastern croatia).geol. croatica, 48/2, 155-160. jami»i∆, d., crnko, j., prtoljan, b. & mati»ec, d. (1985): strukturni elementi laramijskih pokreta u podruëju sulkovca (poæeπka gora).geol. vjesnik, 38, 149-154. kochansky-devidé, v. (1979): srednjomiocenske kongerijske naslage poæeπke gore.geol. vjesnik, 31, 69-72. kochansky-devidé, v. & sli©kovi∆, t. (1978): miocenske kongerije hrvatske, bosne i hercegovine.palaeont. jugosl., 19, 1-98, zagreb. larsen, v. & steel, r.j. (1978): the sedimentary history of a debris-flow dominated, devonian alluvial fan a study of textural inversion.sedimentology, 25, 37-59. lawton, t.f. (1986): fluvial systems of the upper cretaceous mesaverde group and paleocene north horn formation, central utah: a record of transition from thin-skinned to thick-skinned in the foreland region.in: peterson, j.a. (ed.): paleotectonics and sedimentation in the rocky mountain region, united states. am. assoc. petrol. geol. mem., 41, 423-442. leeder, m.r. (1995): continental rifts and protooceanic rift troughs.in: busby, c.j. & ingersoll, r.v. (eds.): tectonics of sedimentary basins. blackwell, cambridge, 119-148. massari, f., mellere, d. & doglioni, c. (1993): cyclicity in non-marine foreland-basin sedimentary fill: the messinian conglomerate-bearing succession of the venetian alps (italy).in: marzo, m. & puigdefabregas (eds.): alluvial sedimentation, int. assoc. sed. spec. publs., 17, 501-520. miall, a.d. (1978a): facies types and vertical profiles in braided river deposits: a summary.in: miall, a.d. (ed.): fluvial sedimentology. can. soc. of petrol. geologists mem., 5, 597-604. 75paveliê & kovaëiê: lower miocene alluvial deposits of the poæeπka mt. ... miall, a.d. (1978b): tectonic setting and syndepositional deformation of molasse and other nonmarineparalic sedimentary basins.can. j. earth sci., 15, 1613-1632. miall, a.d. (1990): principles of sedimentary basin analysis.springer-verlag, new york, berlin, heidelberg, 668 p. miall, a.d. (1996): the geology of fluvial deposits.springer-verlag, berlin, heidelberg, new york, 582 p. nemec, w. & postma, g. (1993): quaternary alluvial fans in southwestern crete: sedimentation processes and geomorphic evolution.in: marzo, m. & puigdefábregas, c. (eds.): alluvial sedimentation, int. assoc. sed. spec. publs., 17, 235276. pami∆, j. & prohi∆, e. (1989): novi prilog petroloπkom poznavanju alpinskih granitnih i metamorfnih stijena motajice u sjevernim dinaridima i bosni.geol. glasnik, 145-176, titograd. pami∆, j. & ©parica, m. (1983): starost vulkanita poæeπke gore.rad jazu, 404, 183-198, zagreb. pami∆, j., injuk, j. & jak©i∆, m. (1990): prilog geokemijskom poznavanju gornjokredne bimodalne vulkanske asocijacije poæeπke gore u slavoniji (sjeverna hrvatska, jugoslavija).geologija, 31/32, 415-435, ljubljana. paveli∆, d. (1998): taloæna evolucija slatkovodnog donjeg i srednjeg miocena sjeverne hrvatske na temelju analize facijesa.unpublished phd thesis, university of zagreb, 149 p. rögl, f. & steininger, f.-f. (1983): vom zerfall der tethys zu mediterran und paratethys. die neogene palaeogeographie und palinspastik des zirkum-mediterranen raumes.ann. naturhist. mus. wien, 85, 135-163. royden, l.h. (1988): late cenozoic tectonics of the pannonian basin system.in: royden, l.h. & horváth, f. (eds.): the pannonian basin. a study in basin evolution. am. assoc. petrol. geol. mem., 45, 27-48. royden, l.h., horváth, f. & burchfiel, b.c. (1982): transform faulting, extension, and subduction in the carpathian pannonian region.geol. soc. am. bull., 93, 717-725. royden, l., horváth, f., nagymarosy, a. & stegena, l. (1983a): evolution of the pannonian basin system. 2. subsidence and thermal history.tectonics, 2, 91-137. royden, l., horváth, f. & rumpler, j. (1983b): evolution of the pannonian basin system. 1. tectonics.tectonics, 2, 63-90. rumpler, j. & horváth, f. (1988): some representative seismic reflection lines from the pannonian basin and their structural interpretation.in: royden, l.h. & horváth, f. (eds.): the pannonian basin. a study in basin evolution. am. assoc. petrol. geol. mem., 45, 153-169. rust, b.r. (1978): depositional models for braided alluvium.in: miall, a.d. (ed.): fluvial sedimentology. can. soc. petrol. geol., mem., 5, 605-625, calgary. stanistreet, i.g. & mccarthy, t.s. (1993): the okavango fan and the classification of subaerial fan systems.sediment. geol., 85, 115-133. steel, r.j. (1988): coarsening-upward and skewed fan bodies: symptoms of strike-slip and transfer fault movement in sedimentary basins.in: nemec, w. & steel, r.j. (eds.): fan deltas: sedimentology and tectonic settings. blackie, london, 7583. stegena, l., geczy, b. & horváth, f. (1975): late cenozoic evolution of the pannonian basin.tectonophysics, 26, 71-90. ©iki∆, k. (1995): strukturni odnosi i tektogeneza πireg prostora medvednice.in: ©iki∆, k. (ed.): geoloπki vodië medvednice, 31-40, inst. geol. istr. & inaindustrija nafte d.d., zagreb. ©parica, m. & buzaljko, r. (1984): geoloπka karta sfrj 1:100.000. tumaë za list nova gradiπka l 33-107 (geology of the nova gradiπka sheet).geol zavod zagreb and inst. geol. sarajevo (1983), sav. geol. zavod beograd, 54 p. ©parica, m. & pami∆, j. (1986): prilog poznavanju tektonike poæeπke gore.rad jazu, 424, 85-96, zagreb. ©parica, m., juri©a, m., crnko, j., ©imuni∆, a., jovanovi∆, ». & æivanovi∆, d. (1979): osnovna geoloπka karta sfrj 1:100.000. list nova kapela l 33-108 (nova kapela sheet).inst. geol. istraæ. zagreb and geol. zavod sarajevo (1972), sav. geol. zavod beograd. ©parica, m., juri©a, m., crnko, j., ©imuni∆, a., jovanovi∆, ». & æivanovi∆, d. (1980): osnovna geoloπka karta sfrj 1:100.000. tumaë za list nova kapela l 33-108 (geology of the nova kapela sheet).inst. geol. istraæ. zagreb and inst. za geolog. sarajevo (1972), sav. geol. zavod beograd, 55 p. tari, g., báldi, t., báldi-beke, m., horváth, f., kovács, a., lakatos, l., nagymarosy, a., pogácsás, g., sztanó, o., vail, p.r. & vakarcs, g. (1992a): tertiary sequence stratigraphy of the pannonian basin.in: sequence stratigraphy of european basins. cnrs-ifp, abstracts, 90, dijon. tari, g., horváth, f. & rumpler, j. (1992b): styles of extension in the pannonian basin.tectonophysics, 208, 203-219. 76 geologia croatica 52/1 waresback, d.b. & turbeville, b.n. (1990): evolution of a plio-pleistocene volcanogenic-alluvial fan: the puye formation, jemez mountains, new mexico.geol. soc. am. bull, 102, 298-314. manuscript received april 7, 1998. revised manuscript accepted may 28, 1999. geol. c roat. 49/2 19 1 195 7 figs. 1 tab. zagreb 1996 scientific paper organic geochemistry in the rationalization of oil and gas exploration and production gerlrud baric key words: source roc ks, organ ic fac ies, maturi ty, pe troleum alte rat ion. abstract organic geoc hemistry. a comparatively youn g scientific d isci­ pline integrated into the basic geological model can affect the reduc­ tion of o il and gas exp lo rati on ri sks. t he correct lise of these dala, panicularly on a regiona l level, so-called geochemica l mapping, has been success fu l in di scovering the hydrocarbon reservo ir. by select­ ing rclcv:li1! geochemical parameters (source, migration, temperature regime) il has been possible 10 obtain p<l ft icli lary useful inform ati on aboui margina l, markedly unfavourable parts of lh e basin. wh ere ex pl oration costs arc very high. the geoc hemic:l! re sults arc used as co rrelat io n paramete rs, not on ly in ex ploration, but al so duri ng hydrocarbon produc ti on. th ey enable determination of reservoir destruction , as well as co mpositi on change of reservoi r hydrocarbons . howeve r, the combination o f all geo log ical and geopbysica l met hods and techn iq ues in the course of exploration process results in the ma ximum effect of geoc hemical prospection. 1. introduction oil and gas exploration is a complex process requir­ ing the application of numerous geological, geophysical and geochemi ca l methods. every mcthod has cert a in d isadvantages anci it s proper selec tion is impera tive to gain the maximum benefits and reduce exp lora tion ri sks (mu rri s, 1984). the old theory that oil is so widespcad in sed imen­ lary basins that it "generates everywhere and mi gra tes anyw here" has becn abandoned long ago. the mecha­ nisms of hydrocarbon generation, migrat ion and accll­ mulat ion are well known today and are considered uni­ versa l, but depend on basic fact s, i.e. sources, rese r­ voirs, cap rocks and traps (demaison, 1984). geochemistry, as a relati vely new scientifi c di sci­ pline, is primarily used in the process of explora tion ror hydrocarbons, since it enables the determination of so urce rocks, eval uati on of their generating potential , effi ciency or expulsion and detection of migration phe­ nomena. the genetic characterization of reservoir hydrocarbons is achieved by th e applica ti on of geolna -nafiaplin, exploration and development di visio n, lov inciceva i , iir loooo z<lg reb, croatia. proceedings kljucne rijeci: maticne stijene, organski fac ijes , zre­ lost, izmjenjenost ugljikovocli ka. sazctak organska geokemija, rclaliv no mlada znllllstvcna discipi ina , inle­ gri mml u osnovn i geoloski model moze utjecal i na sm:lnjenje ri zik a pri istraiivanju nafte i plina. tspnw na primjena ov ih podataka poseb­ no na reg ionainom planu , tzv . geokemij sko kartiranjc, pokazalo jc ii spjeh u ol krivanju leiista uglj ikovodika. tzbororn re levantn ih geokemij skih paramclara ( izvor, mi g racija. icmpcralurni rdim), mog ucc je dobiti posebno kori sne in formacij e ii g rani cnim, izrazilo nepovo ljnim dijelovima bazena , u kojima su cijcnc istrazivanja vrlo visokc. osirn it istrazivhnj u i lijekom proizvodnje uglj ikovodika koriste sc geokemijski rezu lta ti kao korejacijski pararnctri. nj ima je moguce takodc r utvrditi destrukciju id ist a, kao i izmj enu sas tava lci isnih uglj ikovod ika. maksima lan ueinak geo kernijske prospekcije pos ti zc sc ko mbi ­ nacijom sv ih geoloski h i gco fi zic kih metoda i tchnika u is traznolll procesu . chemical analyses, as well as by the ir co rrelation, iden­ tifi cation of al terati on and trans formation of hydrocar­ bons wi thin accumu lations. an objective evaluati on of the role and application of" geochem istry is possible today and its importance in the hydrocarbon exp loration process has also been defin ed. greater efficiency in the search ror hydrocar­ bon resources and discovery 0[" hydrocarbon reservoirs can be achieved by incorporating geochemical data into basic geological models. 2. results and discussion the paper presents the results o f geochemical inves­ tiga ti on carried ou t to date in the croati an part of the pannonian basin, in the dinaridcs and in the adriatic offshore. the main oil and gas fi e lds in croatia are located in the south-western , marginal part of the pan­ nonian basin (fig. 1). research included the identifica­ tion of source rocks, genelic characteri za tion of hydro­ carbons within accumul ati ons, detennina tion of alter­ ation and destruction of hydrocarbons within reservoirs and ex planation of the mechanisms for the appearance o f high concentrations of chem ica ll y inorganic con192 kaalovac " kaapina zagreb @ ca)(ov~c vaaiizoln % sisak " " '<9l..~ ko~ivn1ta ~~, " vii'!ovitica ® potega ® legend _ oilfield .,. gas field slavqnsi( i eaoo ~ ~ ,,", ~..j ,--, geologi:j. croatica 49/2 " __ ... ~r rj § ~--;; :,:: r) ' l-__ ~~ ________________ ~ ______________________ ~ _______________ ~ __ -= ____ ~ __ ~ \ i } 6 300 000 6'" 000 fig. 1 index map with oil and gas fields in the croati an part of the pannonian basin. depression mura drava west drava east sava depth (rn) >3000 >3000 >2100 >2300 thickness (m) 200-500 200-500 200-300 100-300 mid. to low. mid. to low. mid. miocene mid. (0 low. age miocene miocene, mesowic miocene lithology mudstone, mudstone, marlstone marly limestone siltites silt it es limy marls toc (%) average 0.9 1.5 1.2 1.4 kerogen lype iii (i i) 111 -(1 1) ii (ill ) 11 (1 11) maturity (% ro) 0.7 1.8 0.5 2.2 0.4 0.9 0.6 o.~ b 13cl'd13 (%0) -25.8 to -2~.7 -26.3 [0 -28.s -22.3 to -26.2 -21.6 to -26.6 table i basie source rock qlmlity data in the croatian part of the pannonian basi n. sti tuents in gas and gas-condensate fie lds of the mura and drava depression. in the croatian pan of the pannonian basin, source rocks were identified in a large number of wells by geo­ chemica l analyses and the regional determinat ion of sedimentation facies (table 1). source rocks are pre­ dominantly marly limestones and limy marls of lower to middle miocene age, while bacteria-degraded algal matter and terrigenous lip ids are the precursors of petroleum t • recent investigation established that thick, compact dark-gray (0 black carbonaceous fossiliferous mud stones, clayey mudstones and si ltstones of lower m iocene and mesozoic age at depths exceeding 3,000 m in the mura depression and in the western part of the drava depression represent source rocks in these areas (figs. 2 and 3). terrest rial organic matter and longer exposure to high temperatures resulted in generation of gas-condensate and dry thermogenic gases (baric et a l. , 1990, 1996). geochemical characterization of hydrocarbons with­ in the reservoirs (fig. 4) confi rmed that they genetically belong to the determined source rocks and at the same time established the relatively short source rock accui corn ford , c. (1989): petrol cum gcochemistry of the pannonian 13asin.unpublished ecl report, lna -naftaplin archive, zagreb. n ~ric: org~nic gcochem istry ill tile r~tionalizatio ll of oil and gas exploration and production 193 foct .. hi i ~i~i "gh ''''''' "'" 00 o ~ "'" ~::: ~=~ ayofiia ex'''' ca i foc gas/oil ~s~ :10000.010 iqo tilo 19g i i i 1 i i i i 1 i 1 ~ i i 1 i i ji co 1 i ~ , ~i i =i i i ~ i i ~i i ~i i ~ i i i i i mulation migration paths. the investigat ion confirmed that in som e oi l fields of the east dra va depression source rocks, fi ne-grained pellitic sediments also repre­ sent cap rocks, and in certain locali ties they si multane­ ously act as source and reservoir rocks due to secondary porosity (hernitz ct ai., 1995). mura -2 gas paone vitrinite ilerk'ln(t "'_'.~ .fu ........ ouoi.cu.ated i~ .""..&.5i..reo ..... "'110 •• .~ tm • x ·c ~ .~ i i . .., .~ maturity zones liielo5t ii, ~i~i! :i 0 ~ ; fig. 2 organic facies and maturity log of mllra-2 wel l (afte r baricetal., [996). current results indi cate that duri ng furt her explo­ ra tion in the c roatian part of the pannonian basin the type of hydrocarbons can be predicted. the generating poten tial and volume of the de termined source rocks are mostly in agreement with th e size of the ex ist in g hydrocarbon accumulat ion. geological and gcoehcmiln~ nil/tapl h' 80 ie) \-\--7''''''''-----\-------'''<-'+-1 l())jea ponti an upper pannol-i u n lomea p~nnon ian d early "'a tur~ ~(o 1ilil" 0.5 to 0.7 • mid matur e (0\ 1) 0.7 to \ ir+l late mature (0\ 1) !tm, t o 1.3 eggenbutlgian 1i!00. hlta$s!c , • 0 fig. 3 burial history curves for mllra-2 wel l (after bari c ct ai., 1996). 194 legend' -10 + f b 0 "" -so • k,i xm [::, 51g i .... kb • -'0 ii () l1 t u [j mic p ." <d ·'0 2.0 <d lsn " 4 ,0 0 01 -30 .. hlml ~ ok, thhl 0 g, -20 0 • l'9 250 -200 '50 10() -50 x go 50 ch • i""'i fi g. 4 isotope ratios of natural gases in the western part of the drava depression (gene tic zonation aner schoell, 1983). cal reinterpretation or certain areas has to be undertaken to evaluate further prospectivity of exploration areas and greater attention has to bc paid to those localities in which source-rocks have been determined, but in whose vicinity hydrocarbon reservoirs havc not been discov­ ered. source rock seq uences have been determined in deep exploration well s of the adriatic offshore, sample 1 (2 144.2153m) sample 2 (2300-2311 m) • samp le 4 _~'.lj..lu-l. ,,1: 111~~h fig. 6 gas chromatograms of condensates and bitume n in the mum depression. 900 000 ><700 : ~6001 w _ °u ~ :~o > e x 1.00 [[ )00 200 100 iii geologia croatiea 49/2 o ol-____ i __ ~~~=-____ __ 1.30 1.65 immature loll zone i gas zone , mo' ( ' c) fig . 5 hi t",u diagram showing types and malurity of kerogen in lhe dugi olok basin (adrialic offshore). although their regional dis tribution has not been fully defined. the organic matter in those sediments has not yet reached the stage of maturity, i.e. the oil window (fig. 5). poor physical characteristics of cap rocks, which permit migration of hydrocarbons, arc a special problcm, as bi tuminous impregnations and bi tu men­ filled stylolites confirm (baric et ai., 1988). geochemical analyses were used for determination of the alteration of reservoir hydrocarbons. the most frequent eases are caused by processes of evaporative fract ion ation (thompson, 1987; silverman, 1965). fractionation phenomenon caused by structural deformation or a low degree of regional seal elleetivc­ ness (demaison & huizinga, 1991) arc manifest­ ed in the separation of the saturated gas phase from gas­ saturated liquid. separation resu lt s in dispersion and dismigration of light hydrocarbons, whi le residual hydrocarbons remain in the reservoir and, depending on the quantity of waxes or resin-asphaltelle components, increase thc viscosity and cause difficulties in produc­ tion. the reservoirs in (he mum depression are charac­ terized by different degrees of alteration through cvapo­ rative fractionation and in some cases by the total destruction of hydrocarbons (fig. 6). alteration of hydrocarbons in a reservoir can be influenced by water action, too (tissot & \velte, 1984). water washing processes usually characterize shallow accumulations with active hydrodynamic flows. those processes only sligh tly affect the compo­ sition and physical properties of oil. a higher stage of degradation is the result of the combined ac ti on of water and microorganisms, known as biodegradation. depending on their in tensi ty, partial or full alteration of l3:l ric: organic geoche mistry in the rationalization of oi l and gas exploration and production 195 p, ph fig. 7 gas chromatograms of oil s (sava depression) altered by water action. certain types of hydrocarbons is possible. differenllev­ els or biodegradat ion have been established at the bu­ njani field, while tota l alteration from paraffinic-aro­ matic to naphtcnic-aromatic type characterizes the kriz field oil (fig 7). stud ies rescarc hing the origin of chemically inor­ ganic const ituent s (h 2s and co2) in the molve-kalino­ vac-stari gradac field gases, as well as in the exp lo­ ration loca liti es of vuckovec and vukanovec, were conducted in our geochemical laboratory. it was deter­ mined th at h2s was the result of the thennocatalitic reduction or dissolved sulphates with the simultaneous partial su lphurization of reservoir hydrocarbons. the processes arc thermodynamically controlled, and cyclic, but higher em ission s and degasification can be pred ict­ ed by continuous monitoring of lluid during production (bari c & jungwirth, j 995). carbon dioxide in gases is of inorganic origin, and occurs as a result of the thermal decomposition of reservoir carbonates or car­ bonates from the deeper parts of the basin. changes of equ ilibrium in reservoir sys tems are the res ult of decreased formation pressure, primarily caused by explo itat ion, but can also resuil from thc breakthrough o f formation water with large quantities of di ssolved co2, which causes an increase in the co2 levels in gas­ es of some wells. 3. conclusion a short rev iew of thc results indicates that in th e forecasting and es timation of the further prospectivity or exploration areas, a re latively large amount of ex isting geochemical data has to be used in addition to other geological and geophysical methods, to lower the risk involved in findin g new hydrocarbon reservoirs . th e results also indicate that geochemistry can be success­ fully appli ed in solving the problems arising in the process of hydrocarbon production. 4. referenc es baric, g., brttvic, v. & dragas , m. (1996): source rocks and hydrocarbon accumulations in the mura depression, republic of croatia.nana, 47/1., 25 -34, zagreb. baric, g. & jungwirth, m. (1995) : pocirij cllo h2s i organsko sumpornih spojeva u plin sko-kon­ dcnzatnolll polju simi gradec.1. c roatian geologi­ ca l congress, opatija, proceedin gs, 1, 47-51, zagreb. baric, g. , maricic, m. & radlc, j. (1988 ): geo­ chemical characterization of organic faci es in the dugi otok basin, adria tic sea. organic geochem­ istry , 13,343-349. baric, g. , mesic, i. , jungwirth, m. & spanic, d. (1990): plinsko i plinsko-kondcnzatna polja molve, kalinovac i stari gradac.nana , 41/2, 7189, zagreb. demaison, g. (1984): the generati ve bas in con­ cept.in: demaison, g. & murris, r.j. (cds.): pe troleulll geochemistry and basin evaluation. aapg memoir, 35, i-is. demaison, g. & huizinga, b.j. (j991): genetic class ification of petroleum systel11s. aapg bull. , 75/10,16261243. hernitz, z., vellc, j. & baric, g. (1995): origin o f hydrocarbon s in th e eas tern part of the drava depression (eastern croatia).geologia croa ti ca, 48/ j,87-95. murris, r.j. (1984): introduction. in: demaison, g. & murris , r.j. (ed s.) : petro leum geochem­ istry and basin evaluation. aapg memoir, 35. silverman, s.r. (1 965): migration and segregation of oil and gas.aapg memoir, 4, 53 -65. schoell, m. (t983): genetic characterization of nat­ ura l gases. am. assoc. pe trol. gcol. bull., 67, 2225 -2238. thompson, k.f.m. (1987): fractionated aromatic pet roleum and generation of gas-condensates .­ organic geochemistry, 11/6, 573-590. tissot, b.p. & welte, d.m. (j984): petroleum for­ mation and occurrence.2nd cd ., springer-verlag, 459-469, new york. 196 geologia croalica 49/2 i geol. croat. i 50/2 12s[ 260 [0 figs. zag reb [997 tectonic structures along the periadriatic lineament in slovenia pero mioc key words: pcriadriatic lineament , karavankc, tecto­ nic st ruc tu re, zone of periadriatic lineament, ol1h­ ern karavankc thrust, velunja thnlst, olsev3-kosuta thrust, southern karavanke thrust. abstract the pcriadriatic lineament extends from the sesia zone in italy across southern austria into slovenia, in (he area of the kara vanke mounlains. ii co ntinues eastwards into the pannonian basin in hun ­ gary as [he l3alalon linc. the karavanke mountain range run s from slovenia in the cast wcslw,lrds into the carnian alps of austria. fur­ ther cast ihey ex tend beneath [he tert iary sediments of the pannonian basin in lo ilungary. the karavan kc mountains represent a boundary zone between the eastern alps to the north and the jul ian and savi­ nja-kamnik alps or southern alps to the south. the periadriatic line­ ament intersects the eastern pan of the kar<lvank e mountain s from austria. trending eastwards, dividing this unit into the northern and southern karavanke. geologically, the karavanke mountains consis t of palaeozoic, mesozoic (moslly triassic) rocks and tcrtiary sediments. in the easl· e rn part of ihe karavanke mountains, along the periadriatic linea­ ment, th ere i~ a belt of lll:lgmatic rocks, g ranite in the north and tonalite in the so uth, with 1.1 narrow belt of metaltlorphic rocks in between. the tectonic structure of the aforementioned boundary zone is especially inte resting. new research resull~ show that both the overall structure (1i1d individual tectonic units respectively of thi s zone sleeply deep towards the south beneath the julian and savinja (kam­ nik) alps. the karavank e mountains are on the north thrusted over ea stern alps by horizontal movements along sing le faults. among these faults, the periadriati c lineament. along which [he mentioned magmatic (granitc tonalite) zone appears, is especially interesting. this paper attempts 10 define the seq uencc o f tectonic move­ ments which took place at the end of lh e alpine geotectonic cycle, and lhe tectonic structure or the karavanke m1. zone. 1. introduction the peri adriatic lineament represents an important tectonic line. it extends from the sesia zone in italy across austria into slovenia and across the north-west­ ern part of croatia into hungary in the direction of the balalon line (fig. i). lis lotal !englll exceeds 700 km. the geotectonic position , significance and length or the lineame11l allracted the attention of numerous researgeological survey, dim iceva 14, slo-iooo ljubljana, slovenia. kljucne rijcci: periadrijatski lineamen t, tekton ska struktura, zona periacirijatskog iineamenta, navlaka sjevern ih karavanka , velu nja navlaka, navlaka olseva-kosuta, navlaka juznih karavanka. sazetak periadrialski lineament koji se pruza od sesia zone u ltaliji , pre ko juznoga dijeta austrije scz.c u sloveniju na podrucju karavank.i. pre­ ma istoku sc nastav lja na podrucje panonskog bazena ii mad zarskll kao balaton linija. karavanke se protczu iz pravca istoka u sioveniji i u pravcu zapada se nastavljaju u karnijske alpe u austriji. n:l is tok scz ll pod tercijarnc sedimcntc panonskog bazena i pre laze u madzarsk ll. uzduz svog pru zanja karavanke predslavljaju granicn ll zonu izmedu istoenih alpa na sjeveru i julijskih te savinjsko-kam­ niskih alpa odnosno juznih alpa na jllgu. u isloeni dio karavanki prelazi iz alistrije na isl0k periadriatski lineament , koji razdvaja iii jedinicli na sjcverne i juznc karavanke. u geo loskoj gradi karavanki nastupaju pal eozojske i mezozo­ jskc, prelezno irijaskc nasi age ie terc ijarni sed imenti. u is toc no lll d ijelu kanwan ki javlja sc uzduz periadrijalskog lineamenta pojas magmatski h stijena, granit u sjevernom i tonalit u juznom dijel u pojasa, a izmedu njih se proteze uzak pojas mctamorfnih stijena. u gcotektonskorn smislu karavanke prcdstavljaju granicnu zoilu izmedu istoenih alpa i jllznih alpa. posebno je za nimljiva teklonska grada spomenu tc granicnc zone. noviji rezuliati istraiivanja ukazuju da s trllkture odnosno pojedine tek tonske jed inicc te zonc padaju slr­ mo prcma jugu pod julijske i savinjskc (kamni ske) alpe. prcma sjeveru su karavanke navucene na istoene alpe. pri tom sll zanimlji­ va relat ivna horizontalna kretanja lizdllz pojedinih rasjcda. medu ras­ jcdiohl jc posebno znacajan spome nllti periadrijat ski lineamcnt. uzdll z kojeg<l se pojavljuje prije s pomenllta magmalska (granilllo tonalitna) zona. analizom s po menlllih rezullata novijih istraiivanja. prika zat cemo redoslijed tektonskih krctanja krajern alpidskog geotekwllskog cik lusa i tektonsku gradu ave zonc. chers, whereby it has been given diffe rent names e.g. the "a lpine-dinaric sulure'· suess (1909). ihe "a lpine­ dinaric boundary" tollman (1963), and the "peri­ adrialic lineament" of angenheister & bugel (1972). the periadrialic lineament extends in slovenia from the austrian border aiong the castern part of the kara­ vanke mountains which it divides into the noilhern and soulhern karavanke. the eastern karavanke form a this paper was presented at the scientific meeting dedicated to the 80th anniversary of the life of professor milan herak, held on march 5th, 1997 in zagreb • ' a " e r' c v f{ 1 a ill ,\'uhric line o milullo v<;:u ,u~,;, ..... ,v,il' ... 1 .'vl i. ----------------~ 50 km fig. i the geographic pos ition o f the periadriatic lincamcnt from iverca wilc in ital y to the panollnian basin in hungary. belt 10 to 15 km wide, and approximately 60 km long from the boundary of the pannonian basin to the east. the total length of the western and eastern part of the karavanke mountains from jcsenice in the west to the boe mountain and pannonian basin respectively in the east exceeds 150 km (fig. 2). the karavanke mountain range represents orogcne­ ticaliy, a very impressive mountain range which contin­ ues westwards into the carnian alps of austria. it extends as a narrow belt along the slovenian/austrian border from west of jesenice, eastwards via kosuta, olseva and boe , before passing into the basement of the pannonian basin. the northern boundary of the karavanke mountain range is defined , from the west to the cast, by the mezi­ ca-vitanje tectonic ditch, and the southern part of poho­ rje , at the southern s ide of the western part they are divided from the julian alps by the sava fault, and are also surroundcd by the savinja alps and the velenje­ dobrna basin. the most eastern part of the southern karavanke mountains extends into the area of halozc. the interesting geological composi tion of the kara­ yanke mountains has attracted the attention or many resea rchers. teller (1899) wrote about the geo lo­ gical structure of single parts of the karavanke moun· tains, and produced maps for eac h of those pans. diener (1903), collecti ve ly named the karavanke mts., carnian and zilja alps as thc drava belt (drau­ zug). rakovec (1956) published an overvi ew of the tectonic structure of slovenia, including the karavanke mountain area. anderle ( 1970) wrote about the tec­ tonic structure of the weste rn part of the karavanke mountains and bemmelen ( 1970) about the tcetonics of the eastern part of the southern alps. in the same year, strucl (1970) produced an ovcrvi ew of the geological structure of the northern part of the eastern karavanke mountains in the area around mezica. lately, the karavankc area was studied for produc­ tion purposes for the bas ic geological map, sca le 1:100,000. the western part was s tudied by buser (1980) for the celovcc sheet. the eastern part was stud,... . . '" \ p. j ~gt r ._.-:~. ~/.-.-j 0 i~ vlllach 0 klagenfurt 0 / ~ dr..... " pannonian b "q -. ... _ _ • eastern alps aribor ... '..q .., (/ , ~.~ ~~!~",~~ne ~, i? y a u s l. jill': jesenice ,-a ~ i n j[. 'o/lev. ._-'tkfi. p 0 h 0 r j e r ~ 0 , 4 n alp so ...... r, e (u2') ii· ." .f'akovec' _ nagykaniz _ 2164" ~ ~ trl / grlrtt/l .~ ovelenje dr.vl " ,o~~,j -\ • ii·v jr4mj:!s~)savi"'j.a b h""'" r---""'-------'>--~ \ ~ -. .~ '. / ( o • • uoine i fig. 2 the geographic position of the karavankc mountains. mioe: tectonic strucl\jres along thc pcriadriatic lincament in slovenia .l.. / ) -.ii ~ -« a ( j50 u s __ j50 --­ '253 \ ''-/ / --­ '\ o lo uubuana .......... i ,. -, .... i i -. --'/ ''zagreb o fig. 3 a generalised tectonic map of the karavanke mts. with [he bound.ary tectonic un its of the eastern alps, julian-savi nja alps and panon­ nian basin . legend: jso) julian-savinja units; sko) south karavanke overthrust: o k) olseva-kosula overthrust; pl) peri adriatic linea­ men t; zpl) zone of periadriatic lineamenl ; nko) north karavanke overthru st; ma) middle austroalpine; ua) upper austroalpine; t ) tonalite of pohotje; b) neogene basins; po ) pannonian basin; 1) lavantal fault; 2) sava fault; 3) ljulomer fault ; 4) ruba fault. ied by mioe (1978,1983) and mioc & znjdarcic ( 1983) for the sloyenj gradee and rayne sheets. the most eas te rn extension of the karavanke moumains, reaching into the haloze area, was studied by anicic & jurisa ( 1985) for the rogatee shcet. these authors prepared geological maps and reviews of the geological structure of the studied areas. the peri adriatic lineament runs along the kara­ vanke mountains and divides them into the northern and southern karav'li1ke. near the system of faults , running along the lineament, there is an uplifted part of the metamorphic basement with granite and tonalite. rece ntly these rocks represent a zone dividing the karavankc mountains into three parts . from north south , these are: the northern karavanke, the periadri­ at ie lineament (angenheister & bogel, 1972) or zone of the periadriat ic seam (mioc, 1983, 1984, 1986) and the southern karavanke. in the western part of the slovcnian karavanke mountains, between jese­ nice to the west and olseva to the east, only the south­ ern karavanke mts. occur reaching into slovenia. from olseya to the south to peea to the north all the parts of the karavanke mountains extcnd into slovenia (figs. 2 & 3). 2. stratigraphy subdivi sion of the karavanke mountains into three parts was made according to lithological and stra tigra­ phic charac teri stics as well as the tectonic structure of the single units. to facilitate correlation of the geologi­ cal development with the neighbouring areas of the karavanke mountains, we represent accretionary diagrams for the complete eastern and southern alps (fig. 4). the northern karavanke are formed from si luro­ devonian, permo-triassic and jurassic rocks. the si l­ uro-devonian beds are composed of phylliloidic slates with single plates of diabase in between. these bcds are known as the magdalensberg series (riehl·her· wirsch, 1970). the permo-triass ic clastic sedimentary rocks unconfonnably overlie the lower palaeozoic slates and phyllites of the consol idated pre·alpine basement. the· se sediments are represented by redd ish sandstones and conglome rates of the "yeruccano"-type, which orig i­ nated from weathering of the surrounding metamorphic rocks, and to a lesser extent acid volcanic rocks . they are conformably overlain by the lower triass ic clastic carbonate rocks. in the triassic (scithian) series there are sandstonc, shale and bedded limestone. dolom ite as well as thin bedded limestone of the anisian follow. the ladini an is represented by clayey marl beds in the lower part (pannas beds) with crystalline limestone and dolomite known as the wetterstein beds on top of them. marl s and limestones occur in the carnian sequence and are followed by the norian·rhaetian beds main dolomite (hauptdolomit) and dachstein limestone. bedded lime· stones with cherts and clayey marl sediments belong to the jurass ic, although these mesozoic rocks extend from the lias to the lower cretaceous. the jurassic sediments in the lower parts of litho­ logically heterogeneous sequences are formed from limestone breccias, which are overlain by reddish to greenish platy micritic limestones, which contain cla­ yey mixtures and grade into calci te shales (ramoys major sloven ian part of the eastern and rt::e~~~ra~n:.:e:,:si~[sbo~u~t~hern alps superterrane ":0 zz(i) qo ..... !:: ..... z 00::j <2~ >tertiary cretaceous jurassic triassic carboni­ ferous devonian ordo­ vician zoic legend: 1. ( 4 r b ~ 12 i> ~>i 16 ~ 1 1b 2 3 ...;...0 d . . 5 6 7 el d .' 0"'-' 0 o • 9 10 11 ~ ' . -. w 0 13 14 15 1+ + ++1 ~ fig. 4 accretionary cliagnuns of (he eastern and southern alps in slovenia. legend: i a) facies change; i b) ullcorronn ity; 2) tillites; 3) continental clastics; 4) rcd beds . marine cnviroments: 5) pcl ites: 6) arenites; 7) conglomerates: 8) pelagic carbonates; 9) shallow waler carbonates. volcanic rocks: 10) fe lsic: 11) mafic; 12) inlennediatc: 13) plutonic rocks: 14) ophiol it ic sequence: 15) ages: k = k-ar: r = rb-sr: 16) post-accretionary thrust. & rebek, 1970), these sed iments are interlayered with radiolarian cherts . this basinal sequence was deposited during the lias, dogger, maim and berri­ asian-valanginian as indicated by characterist ic fossils (mioc & sribar, 1975), the limestone radiolarite sequence was also thrusted from the south over the lithological units of the northern karavanke. based on lithological correlation , it can be assumed that thi s sequence was deposited in the northern, distal parts of tethys, the zone of periadriatic lineamelll runs along the norlhern contact of the periadriatic lineame nt and extends from austria int o slovenia near crna east­ wards, and wedges out along the faults, north-cast from velcnje, continuing as a fault into the pannonian basin. the mentioned zone is up to 43 km in length in slove­ nia and up 10 3,5 km wide (strucl, 1970). the zone consists of a gran ite belt jn the north , a metamorphic belt in the central part and a tonalite belt in the south. the gran ite belt on the northern s ide is in tectonic contact with rocks of th e magdalcnsberg series, and on the southern side in primaly contact with the metamorphic belt. along thi s primary con tact, the neighbouring rocks were incorporated into a graniti c magma thus forming intrusive magmatites, (agmatites and ve nites), in the boundary part of the granite and cordierite schists (slates) and appear near the contact in the metamorphic belt (fig. 5). however, many varieties of granite exis t in the granite belt , ranging [rom fine grained, medium grained to porphyritic granite. in some pans, e.g. cofati hill , the granite grades into g ranitoid , and in some places to diorite. the beginning of the alpine orogeny was charac­ terized by intense rifting, which resulted in strong mag­ matic act ivity. in the initial phase there was a granite intrusion. relics of granite . formed at that t ime, arc today found along the periadriatic lineament. numerous authors have published papers on the granite. including exner (1973,1976), faninger & strucl ( 1970), mioc (1983, 1984) and others, isotope analysis or ihe granite gave ihe following resulls: k-a r ~ 245-210 ma, u-pb ~ 230 ma and rb-sr ~ 224-216 ma (cliff el ai. , 1974; scharbert, 1975), accordi ng wh ich ihe gran­ ite and the gran ite intrusion, respectively, are or upper permian triassic age. in the metamorphic belt there arc phyllites (ordovi­ cian-si luri an), amphiboli tes and gneisses, whi ch are considerably o lder. in the upper oligocenc the tonalite mass if originated (k-a r and rb-sr 30-28 ma, schar­ bert, 1975), tile southern kara vgflke consists of the devonian , carboniferous, permian, triass ic, jurassic and tertiary sediments. in the lower devonian there is bedded iimc­ stone, overlain in part by reddi sh breccia. the middle devonian reef limestone with corals and hydrozoa fol ­ lows and in the upper devonian there are beddcd lime­ stones and shales. the lower carboniferou s developed as a n ysch sequence. this includes shales, graywacke, olistostro­ me brcccia, quartz conglomerates and single beds of dark limestone. appearances of quartz porphyry and tuff are also characteristic. the molassc sedimentation began in the upper carboniferous, and is represented mioc: tectonic strucltlrc.~ along the pcri:ldri:uic linealllctll in slovenia i , ,w ---> eofatijev mount (1314 m.j c . 2,5 • 3 km , i fig. 5 schemalic cross·scct ion of the ka ra vanke·granite zone by e rna. legcnd: i) gran ite; 2) porphyroid·gran ite; 3) enclaves of ihe gneiss, amphi bolite and diabase; 4) gneiss and phyllites; 5) magdalensbcrg series (greenish states intruded by diabase sitt s); 6) kornites; 7) tonalite. by quartz sand stones and conglomerates as well as shales with si ngle beds of limestone containing mi cro and macro faunal remains. in the lower permi an there are trogkofel organo­ gen ic limestones, shales, sandstones and co ng lomer­ ates. trbiz breccia and groden clastic layers lie above these beds. the neoschwagcrina limestone is a strati­ graphic equi valent of the mentioned groden layers. in the upper permian there are grey limestones with fossil fauna and dolomite. the age of the palaeozoic, carboniferous and per­ mian sediments has been proven with numerous fossils studied by ramovs and partly kochansky-devide. the foss il fauna has been cited by buser (1980) and mi0c': (1978, 1983, 1984). the triassic begins with yellowish dolomite lying on the uppcr permian beds. it is fo llowed by shales, shaly marls, sandstones and single horizons of bedded limestones. in the middle triassic (anisian) there is bedded dolomite, single horizons of bedded limestones which continue into the ladinian. beds of marl and vol­ cani c rocks (keratophyres and tuff) appear in the ladi­ nian , as well as bedded limestones and dolomites. the upper triassic carnian is represented by limestones, do lom ites and marls, while for the norian-rhaetian main dolom ite and dachstein limestone are most char­ acteris tic. the jurassic is represe nted by bedded limestones with cherts and redd ish marl. the lithological develop­ ment of these beds is similar to that in the northern karavanke. and it is assumed that they originate from the same marine basin. the eocene limestones are the oldest tertiary sedi­ ments of the karavanke mountains. they appear as ero­ sional remnants on the upper triass ic deposits. some of the clastites (marls), which overlie these limestones and are inc luded into the oli gocene, are in fact of eocene age. in the upper oligocene there are breccias, sand­ stones and marl s and characteristic andesite tuff. the 255 tuff is most abundant in the eastern part of the southern karavanke. beside the tuff there are also volcanic brec­ cias and " outflows" or s in gle beds of andes it e. the mentioned vulcanites are also known as the smrekovec series (mioc': , 1983) . these sediment s continue towards the east into the area of hrva tsko zagorje (s im unic & pamic, 1993) and further into the pan­ nonian basi n. the neogene sediments surround the northern kar­ avanke and the eastern part s of the southern kara­ vanke. thcy are represented by clastic sediments which strati graphically range from the ounangian to pli ocene. the quarternary sediment s ineil river valleys and cover the slopes of the alps. the most in tercsti ng arc the glac ial sediments, especially moraines being pre­ served at three different altitudes. 3. tectonics the geotectonic posit ion and correspond ing geolo­ gical and tectonic composition of the karavanke moun­ ta ins have intrigued many researchers. numerous au th­ ors (winkler, 1924; kahler, 1953), have discus­ sed the tectonics of the karavanke mountain s, incl u­ ding rakovec (195 6) who assumed that the kosuta thrust was shifted northwards. the same thru st was mentioned by buser (1980) who interpre ts it to be shifted southwards . anderle ( 1970) di scovered, while researching the austrian part of the western karavanke, that the tectonic units in thi s part were thrust towards the north. struc l ( 1970) wrote about the tec tonics of the no nhern karavanke in slove ni a and also mentioned the thrust of the northern kara­ yanke. sikosek (1971) defined the karavanke mountains geoteetonically as the alpine-dinaride boundary zonc. herak ( 1986) included the karavanke mountains together with the julian and savinja alps into the supradinaricum. according to the resul ts of the latest geo log ical investigations, the northern and southern karavanke were cach divided into two tectonic units, between which lies the periadriatic zone and periad riatic linea­ ment , respectively. in the northern karavankc these are the northern karavan ke th rust and the velunja thrust (mioc':, 1978, 1983, 1984). t hey are foll owed by the peri adriatic lineament and after that the olseva-kosuta thrust and the southern karavanke thrust. the northern karavallke thrust (fig. 6) consists of the middle and upper triassic deposits with the juras­ sic layers caught between them. this unit is thrusted northwards over the tertiary sediments of the mezica­ vitanje tectonic ditch. a single tectonic kl ippen of thi s thrust has been preserved on metamorphic rocks in the area of strojna, and on ostri vrh (sveti duh) of koban­ sko. the tcctonic klippen shows the former size of thi s thru st which lat er di sintegrated and was to a large extent eroded. ne ~ zone of velunja s. a'lps *,.j>e'rlaor'at .. l* thr. ¥zone of the north karavanke scales easteren alps rayne (400 m) )1 fig.6 schematic cross-section of the northern kuruvanke. from the pcriadrialic zone of the south to the eastern alps of the north. legend: i) gneiss; 2) phyllites: 3) miocene deposits: 4) upper triassic dolomite: 5) jurassic deposits; 6) middle triassic-wetterslein limestones ~lfld dolomites: 7) karnian layers; 8) lower triass ic deposits: 9) magdalensberg series: 10) granites (g), metamorphic rocks (m), tonalites (t). single parts of the thrust were stackcd over each other along reverse faults during later tectonic activity. these slacks represent an entire thrust or triassic beds and jurassic pclagic sediments which were all thrusted over the metamorphic basement of the eastern alps. five s ingle stacks were estimated within the frame of the northern karavanke thrust. thrusting over the ciys­ talline rocks north of the present karavanke mountain area had already taken place in the upper cretaceous. later thrusting over the neogene sediments occurred somewhere at the end of the neogene at the timc when the alps were uplifting, indicating a gravitat ional com­ ponent to this thrusting. the veltmja thrust (named after the river velunja) was thrusted northwards on to the triassic deposits of the northern karavanke thrust. from the southern side, the granite of the periadriatic zone has been thrusted over the velunja thrust along a revcrse fault. the com­ position of this tectonic unit includes old palaeozoic s lates of the magdalensberg series whieh dip so uth­ wards under the granite. the periadrialic lineament extends from austria into slovenia as the periadriatic zone. the zone is bounded by two reverse faults and it plunges south­ wards. the reverse faults are the cofatia faull on thc north and the periadriatic lineament , loca lly named smrekovee fault, on the south (figs. 5-7). the zone extends eastwards to paski kozjak where it wedges out and runs as a lineament towards the south-eastern pohoije. the eastcrn extension of the periadriatie linea­ ment is cut by the labat faull, which runs in a nw-se direction along the so uth -wes tern pohorje, where the extension of the lineamen t is shifted towards south­ east. the eastern and north-eastern extension continues along the dravinja river, then along the drava valley, south from ormoz, and further towards cakovec, exte­ nds into the panonnian basin and runs towards balaton in hungary. the geological composition of the periadriatic zone includes a granite belt , metamorphic and tonalite belts. this zone represents a part of the continental c ru st, which was cut along a fault and after horizontal-vertical movement reached the surface. structural clements, including foliation and lineation in the metam orph ic belt, are parallel to the lineament, and the foliation dips steeply (70 90°) towards the sout h. the parallel lin­ eation dips towards the west and south-west (60 80°), which proves horizontal-vertical movements along thc lineament. generally, the periadriatic lineament represents the tectonic boundary between the eastern alps in the nor­ th and the southern alps (julian alps and karavanke mountains in slovenia). single parts of the lineament have loca l names, c.g. the canavese line, insubrie line, guidicaric line, pususte ria line, gail line, smrekovcc line, and in hungary the balaton line (fig. 1). tile ol§eva-kosuig overthru st extends rrom the austrian border in the west, via kosuta, olscva, boc and haloze, respectively, towards the east into the base­ ment or the pannonian basin. it consists most ly of the upper triassic deposits and to a lesser extent, of the jurassic deep marine sediments. in the eastern part, in the area of olseva, this unit bounds to the north to the peri adriatic lineament and dips towards the south (reverse fault), under the sollthern karavankc thru st. the contacts of these two units are clearly visible espe­ cially on the southern slopes of olseva (fig. 7), where the upper carboniferous beds of the southern karamine: tectonic structures along thc periadri~ltic lineament ill slovelli;1 257 ---------------------------------------------fig. 7 the lec(qnic contact of the olseva-kosuw unit with (he southern karavanke unit oil the southern slopes ot olseva. legend: cp) upper carboniferous permian beds (of the southern karavanke thrust); t) the upper triassic dolomites (milonitised) of the olseva-kosuta unit. vanke thrust overthrust the upper triassic sediments (main dolomite) of the olscva-kosuta unit. the juras­ sic sediments arc usually trapped between the triassic sediments. the southern karavanke overthrust (fig. 8) consists of the devonian, carboniferous, permian and triassic beds. the structural elements have, in general, southern vergence. in isolated places, the beds are folded and single parts of the unit disintegrated into numerous smaller parts. the general position of this tectonic unit as a whole also verges towards the south. in the western part or the southern karavanke it dips under the julian alps and in the eastern part of the southern karavankc under the savinja alps. 4. discussion the state of the single tectonic units, in the area directly adjacent to the peri adriatic lineament, is con­ siderably different from the structural state of the tec­ tonic units regionally, e.g. in the sloven ian part of the eastern alps and in the julian and savinje alps. tec­ tonic klippen of the northern karavanke, thrust on the n -----7 __ * _ ~ zone of 0(---south karavanke thrust oj!< olseva kosuta thr.------,.,..-periadriatic l. savinja (660 m.) ~ ii c. 6 km , i fig. 8 schematic cross­ section of the south­ ern karavankc mts. from the peri adriatic lineament to the savi­ nja river. legend: i) permo-carbon iferous layers: 2) triassic sed­ iments: 3) upper tri­ assic dolomites (main dolomite) and dach­ stein limestones: 4) to­ nalite; 5) quaternary rock -fall breccia: pl) peri adriatic lineament. l..jcologm croallcn ':jufl. ~sw ne~ ~ southern alps -+ eastern alps fig. 9 schematic cross­ section between ko­ zjak and tbe savi ­ nja alps. lege nd: i<savinja alps * karavanke -* fsouth+ north 1 pohorje ~ kozjak sa) savinja alps (overthrust): s ko) southern karavan ­ ke thrust; ok) ols­ eva-kos uta thrust; pl) zone of th e peri adriati c linea­ ment; yo) yclunja thrust: nko) nor­ th karavankc thru­ st; te) tertiary de­ posits: ma) mid ­ dle a ust roa lpine: o 10 20 30 km va) uppcr aus­ troalpine; tn) ton ­ alitc. 'l-~ __ ~' __ ~ ___ 'l-~ __ -"' metamorphic comp lex has a subh orizontal position, while tectonic un its ncar the peri adriatic lineament are subvert ical (fig. 9). the force producing these thrusts, as far as we know, was provided by the movement and collision of two "microplates" the adriatic (apulian) and the eas­ tern alps (austroalpini c) microplate in the uppcr cre­ taceous and the tertiary. due to the movement o f the adriat ic plate towards north, the thrust of the southern alps appeared in the same dirccti on (frisch, 1978), and their thrust over the eastern alps (ostalpi num) in the upper cretaceous. at that time, single ihrusts con­ sisting of the lower palaeozoic slates, (e.g. the strojna and remsnik thrust) were sh ifted in the sioveni an part of the eastern alps, as well as the northern karavanke th rust (of the triass ic-ju rass ic sed iments) whi ch was thrusted over the lower palaeozoic rocks. collision of the microplates also caused disintegra­ tion of the southern margi n of the eastern alps plate. classical thrusting stopped, but the continental crust was dislocated and the horizontal-vertical (transcurrent) movements of th e sin gle blocks appeared along the mentioned fault s. si ngle blocks from the basement dis~ integ rated the above laying sediment complexes and some parts, like the pcriadriatic zone, came to the sur­ face (fig. 10). the horizonta l movements are especially dist inctive along the periadriatic lineament, where large facies dif­ ferences of the same strat igraphi c units, recently lying north and south of th e periadriatic lineament can be seen. for example, the permo-triassic was deposited in the area of the easte rn alps in a form of con tinental clastic formati ons, whereas south of the periadriatic lineament the permian and triassic fo rm a marine development. in lombard ia sim ilar permo-triassic sed­ iments lie south of the peri adriatic lineament and have the same mineralogical composition as those in austria and slovenia. on the basis of this, we can conclude that these sediments formed a cohesive regiona l sedimenta­ ry unit. the triassic and jurassic sediments on kosuta, included into kosuta-olseva tectonic unit , were once the same tectonic unit with the corresponding layers of the northern karavanke thrust. it can be concluded that the periadriatic lineament was ac ti ve after overthrusting of the northern kara­ vanke thrust. the pcriadriatic zone reached the surface during or after the miocene, as shown by the inclusions of tonalite fro m the karavanke mountains in the gran­ ites of the ottnangian karpathian sediments (m 10c, 1978). with continuing approach of the adriat ic and aus­ lroalpinic micro-plales, subduclioll of the eastern alps mi cro-plate and anatexa of il s active southern margin occurred. a granitoidic magma was produced as a con­ sequence of these processes. it seems that mafic magma was partially contaminated by continental crust in the southern part of the subduct ion and ana texic zones, respectively. the result o f this mixing was thc kara­ vanke tonalite enriched with hornb lende. the same magma gave rise to the intense andes itic volcan ism. in the upper oligocene, a sialic island ridge wit h a system of volcanoes, which can be traced through the whole of sloveni a from jesenice to rogaska slatina, whe re it crosses to croatia, was formed along the northern mar­ g in of the southern karavanke. south of this ridge, a bas in was formed in which sed imentary-volcanogeni c material was deposited (mioc et ai. , 1986). deposition proceeded from the northern margin area into the basin by mudflows, as reflected in the sedimentary tex tures developed. in the northern part of the basin th ere are coarse to fine grained sediments (from breccia to pelite) with graded bedding, while in the southern part there are mostly laminated layers of turbiditic character. this complex of volcanogenic sediments is called the smre­ kovec series and reaches a th ickness of approx imately 1,000 m (mioc, 1983). northwards, in the area of pohorje, granitoidic mag­ ma havi ng textural characteri stics of tonalite con tains mostly biotite instead of hornblende as a characteristic mineral. dacite appears as its effu sive equ ivalent. it mioe: teclonic strucllires along the periadriatic lincamcnt in slovenia 259 ---------------------------------sa? fig. 10 schematic block-diagrams of the karav<jnke mts. on the border with easlern alps. legend: sa) julian and savinja alps unit; sf) sava faull: sk) southern karavankc overthrust; ok) olsev<l-kosuta overthrust; pl) zone of periadriatic lineament; yo) yelunja ovethrust; nko) north karavanke overthrust; tc) tertiary; ea) eastern alps metamorphic complex. seems that this intrusion occurred a little later, when the miocene dacite volcanism took place in the carpathian. it seems like this part of the intrusive zone was less contaminated with mafic admixtures. in the miocene (ottnangian-carpathian), sedimentation expanded, and a transgression appeared from the southern part towards the north from the lineament. uplifting of the alps during the plio-quaternary caused gravitational overthrusting; from the uplifted parts of the area, over the younger neogene sediments along the margin oflhe northern karavanke. the potocka zijalka palaeolithic station is the most conclusive proof of the intense uplifting in the quater­ nary. thcrc, the rcmains of plants and animals, the food sources of palaeolithic man occur covered by fluvial deposits. acknowledgement the author is grateful to d. brkljaca for his graphical work. 5. references anderle, n. (1970): stratigraphische und tektonis­ che probleme im bereich des ostereiches anteiles dcf vestkaravanken zwischen rosenbach und thorl unter berucksichtigung der alpine orogenese. ­ geologija, 13, 116-132, ljubljana. angenheister, g. & bagel, h. (1972). recent investigations of surficial and deeper crustal structures of the eastern and southern alps.geol. rundsch., 61/2, 349-395, stuttgart. anicic, b. & jurisa, m. (1985): osnovna geoloska karta sfrj i: i 00.000, l33-68. tolmai' za list ro­ gatec (geology of rogatee sheet).zvczni geol. zavod, beograd, 76 p. bemmelen, r.w. (1970): tektonische problemc der ostlichen siidalpen.geologija, 13, 133-158, ljub­ ljana. buser, s. (1980): osnovna geoloska karta sfrj 1:100.000, l33-53. tolmai' lista celovcc (klagen­ furt) (geology of celovee (klagcnfurt) sheet).zve­ zni geol. zavod, 1-62, beograd. cliff, r., holzer, h.f. & rex, d.c. (1974): dthe age of the eisenkapel granite and the history of the pcriadriatic lineament.verh. geo!. b. a., 2-3, 347350, wien. diener, c. (1903): bau und bild der ostalpen und des karstgebietes.ii bd. ball und bild ostene­ iehes, wien, 328 p. exner, c. (1973): geologie der karawankenplutone ostlich eisenkappel, karnten.mitt. geol. ges., 61, 1-108, wien. exner, c. (1976): die geologische position der mag­ matitc des periadriatischen lineamenles.verh. geol. b. a., 2, 2-64, wicn. faninger, e. & strucl, i. (1978): plutonic empla­ cement in the eastern karavanke alps.geologija, 21/1,81 -87, ljubljana. fritsc h, w. ( 1978): a plate tectoni c model of the easte rn alps.in: closs, i-i. , roeder , d. & schmid , k. (cds.): alps, apennines, hellenides. e. schweizerbart. verlagsb. , 167-172, stuttgart. herak , m. ( 1986): a new concept of geotectonics of the dinaridcs.acta geol. , 16, 1-42, zagreb. kahler, f. ( 1953): del' bau del' karawanken und des klagenfurter beckens.charinthia ii , 16, 1-75 , son­ derh. , klagenfurl. m 10 c, p. ( 1978): osnov na gcoloska karta i: 100.000, l-33-55. tolmae za list siovenj gradee (geology of sl ovcnj gradcc shce t).zvczni geo!. zav., beograd , 74 p. m 10 c, p. ( 1983): osnovna geoloska karta i: 100.000, l33-54. tolmao za list ravnc na koroskem (geolo­ gy o r ravne na koroskem shee t) .zvezn i geol. zav. , beograd. 69 p. mioc, p. ( 1984): gcologija prehodnega obmoeja med juznimi in yzhodnimi alpami v sloveniji.unpub­ lished phd thesis, university of zagreb, 202 p. mioc, p. ( 1986): tcktonska gradnja terena uzduz peri ­ adrijat skog sava u sloveniji.xl kongres geologa jugoslavijc , tara, 3, 507-520, beograd. mioc, p. & sribar, l. (1975): jurski skladi severnih karavank (the jurassic beds in the north kara­ yanke mts.).geologja, 18,88-97, ljubljana. mioc, p. & znidarc ic, m. (1983): osnovna geo­ los ka kart a sfrj , ravnc na koroskem l33-54 , i: 100.000. zvezni geol. zav., beograd. mioc, p. , anicic , b. & zntdarcic, m. (1986) . sedimentation o r the sm rekovee sedi mentary-vo l­ canic scrics in the northern slovenia.y. skup sed i­ mentologa jugoslavije, abstracts, 61-64, brioni. rakovec, i. (1956): pregled tektonskc zgradbe slo­ vcnij c.prvi jugoslovanski gcoloski kongres , bled 1954, predavanja in poroeila, 73-83, ljubljana. ljcolog la lroallca ;,u/l ramovs, a. & rebek, r. ( 1970): razvoj jurskih skladov med mezico in s lovcnj gradccm.gcolo­ gija, 13, 105-111, ljubljana. riehl-herwirsch, g. ( 1970): zur aiterss tellung dcr magdalensbergserie mittc lki:irntc ll. oste rrc ich. mitt. geol. ges. , 19, 195-2 14, wien. scharbert, s. (1975 ): radiometri sche aitersdatcn von intrusivgesteinen illl raulll ei scnkappc l (kara­ wanken, karnten).verh. geol. b. a. , 4, 30 1-304, wien. sikosek, b. (1971): tolmai' geoloske karte sfrj jugoslavije 1:500.000 (explanation for geological map of yugoslavia).zvezni gco !. zavod, i-56, be­ ograd. suess, e. (1909): oas antlitz del' erde .tempsky­ freytag, wien-leipzig, 790 p. s im un le , a. & pamie, j. ( 1993): geology and pet­ rology of egerian-eggcnburg ian andes ites from the easternmost parts of periadriali c zonc in hrvat sko zagorje.acta geol. hung. , 36/3 , 3 15-330, buda­ pes t. strucl, i. (1970): stratigrafske in tektonske razmere v vzhodnem delu severnih karavank. gcologija , 13, 5-20, ljubljana. teller, f. (1899): erlauterungcn zur geologi schen karte pragerhof wind. fe istr itz. vcrh. geol. r. a. , wien, 144 p. tollmann, a. (1963): ostalpen-synt hese.veri. deutiehe, wien, 256 p. winkler, a. (1924): ober de n bau del' os tl ichen siidalpen. mitt. geol. ges., 16, 1-272, wien. manuscript received april 14, 1997. revised manuscript accepted novembcr 10, 1997. 1. introduction the structural relationships of northwestern croatia and the adjacent regions of slovenia and bosnia were and remain subject to different treatment. the main approaches are as follows: peters (1863) assumed the existence of an ancient “palaeolithic land” within the balkan peninsula, comprising the “crystalline cores of slavonia and siebenburgen”. this megastructure was not supposed to have participated in tangential alpine tectonics. suess (1875) attributed northwestern croatia (including mt. medvednica) to the southern alps, while diener (1903) regarded the area as part of the eastern alps. mojsisovics (1880) accepted the “land” defined by peters and introduced the name “oriental land”. however, he experienced difficulty in defining its boundaries. pilar (1882) was involved with the geology of western bosnia and concluded that the “flysch”, containing “eruptive rocks” (including ophiolites), continued into croatia. later, ki©pati∆ (1899), studying ophiolites, accepted the opinion that mt. medvednica was a continuation of northern bosnia (i.e., of the inner dinarides), as did also gorjanovi∆-kramberger (1907), with the exception of the part which was tectonic interrelation of the dinarides and the southern alps milan herak attributed to the “oriental land”. salopek (1914), analysing modern tectonic concepts, concluded that autochthonous relationships characterize nw croatia. cviji∆ (1924) accepted the idea of the ancient land (he called it the rhodopian mass) but considered its boundaries as ambiguous. therefore, he proposed to distinguish transitional zones between the “land” and its surroundings. koch (1924) gave preference to the dinaridic elements in the whole area, and included even the slavonian mountains into the dinarides. winkler (1924) believed in north-vergent allochthony in the adjacent area of the slovenian “sava folds”, probably under the influence of suess’s concept of a northward push of the southern alps. in recent times, mio» (1975, 1981) paid special attention to the “sava folds” and to the area of the lower carniolia (dolenjska, eastern slovenia). he defined a unit named the sava nappe which overlies the outer dinarides, and is overlain by a south-vergent nappe composed of elements of the julian and savinja alps. the extension of such relationships should be followed towards mt. æumberak (comprising the area of samobor). premru et al. (1977), by means of some deep boreholes, established a well-marked allochthony in lower carniola (dolenjska) and in the adjacent mt. æumberak. they considered the area as a part of the outer dinarides. the “litija anticline” was defined as the dolsko overthrust (premru, 1983, and earlier). geol. croat. 52/1 83 98 4 figs. zagreb 1999 key words: alps, dinarides, tisia, slovenian trough, sava nappe, pannonian nappe, mid-transdanubian zone, bosnian zone, tectogenesis and geotectonic classification. kljuëne rijeëi: alpe, dinaridi, tisia, slovenski jarek, savska navlaka, panonska navlaka, srednja transdanubijska zona, bosanska zona, tektogeneza i tektogenetska klasifikacija. croatian academy of sciences and arts, a. kovaëiêa 5/ii, hr-10000 zagreb, croatia. abstract the study focuses on northwestern croatia which, including the æumberak (æumberaëka gora), medvednica (zagrebaëka gora), kalnik, ivanπëica, and ravna gora mountains, make a cross area of the slovenian “sava folds”, southern alps, mid-transdanubian zone, tisia, and the inner dinarides. this is a complex structural region and cannot be attributed merely to one of the units. therefore, a geotectonic interpretation is proposed which respects the diversification and multiple superposition of basinal and platform elements. this concept allows linkage of the slovenian trough with the bosnian zone and its southeastern prolongation as a major coherent tectonic unit overlain by different nappe elements. the possible linkage with the budva zone beneath the carbonate nappe is also discussed. saæetak glavna je pozornost posveêena sjeverozapadnoj hrvatskoj, koja ukljuëuje æumberaëku goru, medvednicu, kalnik, ivanπëicu i ravnu goru presjeciπte susjednih slovenskih “savskih bora”, juænih alpa, srednje transdanubijske zone, tisije i unutarnjih dinarida. to je sloæeno strukturno podruëje, pa ne moæe biti pribrojeno samo jednoj jedinici. zbog toga se predlaæe geotektonska interpretacija koja uvaæava diverzifikaciju i viπestruku superpoziciju bazenskih i platformskih elemenata. ovaj koncept omoguêuje povezivanje slovenskog jarka s bosanskom zonom i njezinim jugoistoënim produæenjem u jednu koherentnu tektonsku megajedinicu na kojoj leæe razliëiti navlaëni elementi. takoer se raspravlja o moguêoj vezi s budvazonom. 84 geologia croatica 52/1 the same unit has been subdivided in detail by mlakar (1987). ©iki∆ et al. (1978, 1979), ©imuni∆ (1992), ©imuni∆ & he∆imovi∆ (1979), etc., introduced short distance overthrusting with different vergences to explain the tectonic pattern of mt. æumberak (with the area of samobor) and mt. medvednica as well as of hrvatsko zagorje. they contributed new data to previous interpretations. miladinovi∆ (1981) argued for the existence of an extensive allochthonous unit, called the pannonian nappe. the idea was born in 1974 (see: miladinovi∆, 1981) on the basis of the study of many published papers and with insight from the geologic mapping data. the maps have been made by numerous authors who registered several inverse contacts but did not evaluate them in a geotectonic sense. miladinovi∆ has drawn his tectonic map in 1977 and elaborated in 1981. the nappe concerns only upper palaeozoic and triassic rocks, which overlie cretaceous and jurassic formations. the nappe should cover a broad region stretching from italy through the julian alps, south karavanke and savinja alps, to the “sava folds”, mt. æumberak, banovina, north bosnia, uæice, prizren, pljevlja, “pelagonian massif”, etc. within this megaunit, several tectonic windows and klippen were identified, which include the “zlatibor” window. since the most characteristic areas lie outside the pannonian depression, the name of the assumed nappe has not been generally accepted. likewise, there are some regions that cannot be included into such a simple model of this unit, especially the composite structure called the “pelagonian massif”. as to the western dinarides, the idea itself may be generally acceptable. however, the details require refinement. the possible connection of the slovenian trough with the bosnian zone has been registered in several papers. in mt. æumberak, tornquist (1918) determined pelagic sediments of late tithonian, berriasian and valanginian age. he considered them as a link between analogous slovenian and bosnian deposits. aubouin et al. (1970), cousin (1973), and babi∆ (1973, 1974) were concerned with the same problem, speaking in favour of such a connection. aubouin et al. (1970) assumed the existence of a “furrow”, in which specific (“basinal”) formations have been deposited since the late triassic. however, they do not explain the type of boundary between this “furrow” and the oceanic realm of the inner dinarides, which is characterized by ophiolites and is visible in their reconstruction of the major structures where they propose a direct overthrust of the ophiolitic complex upon the ele ments of the “furrow”. later, babi∆ & zupani» (1978) again evaluated the analogies between the julian alps and the dinarides and contributed some additional elements in favour of a direct connection. however, they also called attention to some difficulties. for instance, between the tolmin selπka sora area and the æumberak area, differences exist in the timing of their aquisition of basinal character. in the tolmin selπka sora region, the basin may be formed during the triassic, while in the æumberak area this occurred no earlier than the end of the lower jurassic. in contrast, dimitrijevi∆ (1982) accepted the existence of a homogenous zone extending from the julian alps, over the “sava folds” and “zagreb zone” (i.e., mid-transdanubian zone in the current terminology), but he placed a sharp boundary towards the dinarides (inclusive of the vardar zone, s . l .). though aware of great differences within the area of the so-called inner dinarides, i preferred to attribute the area in question to a common inner dinaric megaunit (s u p r a d i n a r i c u m) with possible interior differentiation (herak, 1986, 1991, 1995, 1997). for example, the structures consisting of late palaeozoic and triassic rocks were considered as overthrusting parts of the bottom margin of the inner dinarides. more recent explanation of the origin of this nappe requires emendation as discussed later. pami∆ (1993) was concerned with eoalpine and neoalpine magmatic and metamorphic processes in the northwestern vardar zone, the easternmost periadriatic zone and the southwestern pannonian basin. he was of the opinion that the mountains of hrvatsko zagorje “can be interpreted as relics of the sava and/or julian savinja nappes”. he proposed to introduce more dinaridic elements when treating southern marginal parts of the pannonian basin. the participation of dinaridic elements in the mid-transdanubian zone was also acknowledged by berczi-makk et al. (1993). authors from the institute of geology in zagreb use the term mid-transdanubian tectonic zone, which is not delimited towards the inner dinarides (©iki∆, 1995), as did many other authors, e.g. haas et al. (1995). however, by some authors sharp tectonic limits towards the dinarides were assumed (e.g., dimitrijevi∆, 1982). there are many more papers with controversial concepts, but all of them are within the frame of these ideas and, therefore special commentary of them is omitted. by comparison of the proven data in nw croatia and eastern slovenia, the heterogeneity of the region (called the mid-transdanubian zone) is obvious, with the consequence that dinaridic and alpine elements are superimposed. however, the tectogenetic processes and the interior organisation remain under discussion. despite the fact that within northwestern croatia numerous new data, concerning lithostratigraphy and local tectonics, have been collected (©imuni∆ & pami∆, 1989; herak et al., 1990; ©imuni∆, 1992; ©iki∆, 1995; halami∆ & gori»an, 1995, etc.), a general comparative treatment concerning dinaridicalpine geotectonic relations remains elusive. therefore, the major aim of this paper is to rectify that problem. 2. major lithostratigraphic sequences mt. medvednica (zagrebaëka gora) and mt. æumberak (æumberaëka gora) display the greatest diversity of lithostratigraphic units. in a relatively small space there are numerous inverse tectonic contacts indicating piling up of various lithocomplexes that require palinspastic reconstruction of the primary environments. compiled stratigraphic data on mt. medvednica (©iki∆, 1995) include units ranging in age from the palaeozoic to the quaternary. since the main purpose of this paper is the reconstruction of palaeotectonic relationships, the discussion of neogene and quaternary deposits is omitted. as there is a high degree of stratigraphic diversification, the origin of different stratigraphic complexes cannot be explained by means of lateral facies within single consistent depositional areas. usable data have been published in numerous papers cited by ©iki∆ (1995). in this paper, only the most pertinent ones will be taken into account. generally, several primarily consistent lithostratigraphic successions, characterized by features indicating complementary palaeogeographic and tectonic diversification in space and time (figs. 1-4), can be distinguished in the alpino-dinaridic realm, though these are dispersed at the surface. 2.1. variscan basinal formations the palaeozoic, from the silurian to the middle carboniferous, displays prevailingly basinal type of carbonate and clastic sediments. they are exposed in 85herak: tectonic interrelation of the dinarides and the southern alps fig. 1 diversification of mesozoic events in the adjacent areas of the dinarides and the southern alps: u) uppermost platform deposits; s) supradinaric oceanic rocks; d) dinaric platform deposits; e) epiadriatic pelagic deposits and formations with pelagic components. 86 geologia croatica 52/1 mt. medvednica (–ur–anovi∆, 1973; sremac & mihajlovi∆-pavlovi∆, 1983). some outcrops are slightly metamorphosed with relatively well-preserved graptolites, conodonts, etc. even in cases when they are included into the younger metamorphic complex, it is possible to use them as evidence of primary basinal sedimentary conditions. however, in trgovska gora w of the una river, se of zagreb, only non-metamorphic outcrops of the devonian and the carboniferous with conodonts are present (–ur–anovi∆, 1973) what indicates that they do not belong to the same tectonic unit. the change from basinal type of sedimentation in fig. 2 proposal of an emended and generalized map of the dinaridic south alpine joint realm for further considerations; subductional tectonic model, based on selected outcrop-areas with simplified and partially enlarged contours: 1) neogene and quaternary cover; 2) austroalpine; 3) tisia; 4) uppermost nappe (with some tectonic windows); 5) supradinaricum (s. str.); 6) dinaricum; 7) epiadriaticum (pelagic deposits and clastics with pelagic components); 8) adriaticum; 9) ? ionian underthrust; k) mt. kalnik (see fig. 3); m) mt. medvednica (see fig. 3); æ) mt. æumberak with the samobor area (see fig. 4); iv) mt. ivanπëica. 87herak: tectonic interrelation of the dinarides and the southern alps the middle carboniferous is due to the variscan orogeny which formed the structural basis for later molasse sediments. however, variscan megastructures (with some older tectonic elements) are preserved only in the adjacent slavonian mountains belonging to the tisia (jami»i∆, 1983; herak et al., 1990). palaeozoic fragments (together with triassic examples) are poorly preserved as protoliths of the younger metamorphics (greenschists and associated schist members). this rock complex with changed mineral composition originated during the process of progressive lowgrade metamorphism (belak et al., 1995a, b). therefore, it may be treated as a consequence of the alpine tectonic deformations and metamorphism. 2.2. variscan molasse deposits the late palaeozoic is represented by carboniferous deposits with corals as well as clastics, which contain the remains of land plants (banovina, se of zagreb). various plant fragments are also found in mt. medvednica and mt. æumberak. the molasse deposists in the region of samobor are most characteristic. they consist of permian (possibly also of some carboniferous) clastics composed of quartz conglomerates, lithoclastic graywackes, siltites, shales, and sporadic dolomites. the terrestrial origin of the clastic components is further proven by the remains of land plants calamites and sigillaria (jenko, 1944). evaporites were deposited in the transition time between the permian and the early triassic. they are followed continuously by variegated clastics, what may be decisive in the interpretation of the uppermost nappe (fig. 2, u), unifying palaeozoic and triassic deposits as an integral unit which overlies oceanic formations of the inner dinarides. some isolated platform outcrops are “strange” within variscan molasse deposits. possibly they can derive from the subducted (?) dinaric platform. in an eocene breccia in hrvatsko zagorje (vinica and viπnjica w of varaædin), milanovi∆ (1982) found middle carboniferous limestone fragments with foraminifera and calcareous algae. he correlated them with analogous deposits in mt. velebit, banovina, etc. in the area northwest of samobor (near the bregana village), in a small isolated carbonate area, calcareous algae (gymno c o d i u m, a t r a c t y l i o p s i s, etc.) have been determined (herak & ©kalec, 1967). in mt. medvednica a boulder has been found which contains remains of n e o s c h w a g e r i n a ( d e v i d é n e dĕla & kochansky-devidé, 1990). ©imuni∆ (1979) registered lower permian algae in a non-metamorphosed limestone in mt. medvednica. 2.3. tardy-variscan dynamics and the origin of carbonate platforms the main lower triassic components include: sandstones, siltites, marly limestones, oolitic limestones, and some dolomites (in the upper part of the limestones ammonites are preserved). the general tendency of subsidence is obvious. the middle triassic was a time of relative tectonic disquiet, especially in the anisian. some rifting with volcanism (mostly several types of basalts) and clastic sedimentation occurred. however, generally dolomites and dolomitized limestones prevail, continuing also into the ladinian. at several horizons of the middle triassic, small areas of ammonitic limestones have been found. the tectonic dynamics in the middle triassic was tardy-variscan (final), forming the basis for the origin of later carbonate platform areas. in the upper triassic, stromatolitic dolomites and some limestones with megalodontids predominate. carbonate sedimentation lasted until the palaeogene with some oscillations indicated by shallow water clastics and small gaps (crnjakovi∆, 1981). 2.4. mesozoic deposits with pelagic influences the outcrops of late triassic pelagic deposits are encircled either by platform or by oceanic facies from which they can be distinguished: from the platform formations by the type of sediments (platy limestones, radiolarites, etc.), and from the oceanic formations by a lack of a magmatic-sedimentary complex with ultramafics and mafic intrusives. on the nw side they outcrop in the slovenian trough (grad, 1961; cousin, 1973; lapajne & ©ribar, 1973; premru, 1975, 1983; buser, 1977, 1989; babi∆ & zupani», 1978; babi∆, 1980/81; jurkov©ek et al., 1990, etc.). towards the e and se they are present at many isolated sites. in recent times, very important dispersed pelagic outcrops have been described on the northern slope of mt. medvednica and on mt. kalnik (fig. 3), and then on mt. æumberak (fig. 4). at the localities of mt. kalnik the metabasalts, shales and radiolarites outcrop. primary contacts with the surrounding facies are not clearly visible. locally, the outcrops are composed of heavily tectonized rocks. the lower part of the succession is composed of calcitized, porphyritic, ophitic metabasalts. the age of the radiolarites corresponds to the carnian-norian time interval (halami∆ & gori»an, 1995). on the northwest slope of mt. medvednica radiolarian cherts alternate with silty shales. the sediments are intensely folded, partially even overturned. their base is not known due to intensive tectonics, and they are non-conformably overlain by palaeocene calcitic siltstones. however, it is probable that the examined trias sic radiolarites are partially overlain by similar silty siliceous sediments (radiolarian cherts, shales, etc.) of uncertain jurassic age (halami∆ & gori»an, 1995, p. 135). in the adjacent area of mt. hum, nw of mt. medvednica (valley of burnjak), limestones with intercala88 geologia croatica 52/1 tions and lenses of chert outcrop (©iki∆, 1995). discontinuous fragments of pelagic outcrops, belonging to the transition between the upper triassic and the lias are also present, as well as pelagic limestones with radiolarians and lagenid foraminifera of late lias dogger age. some isolated outcrops belong to the jurassic-neocomian, others to the tithonian-berriasian, with a possible “hard ground” at the contact with triassic dolomites (babi∆ & zupani», 1973; babi∆, 1975; ©iki∆, 1995, p. 15). the incompleteness of the columns is ascribed to the condensed sedimentation. in mt. ivanπëica, zupani» et al. (1981), and ©imuni∆ (1992) also emphasized that, due to the “hard ground”, tithonian-valanginian deposits non-conformably overlie different stages of the triassic. explanation of such a phenomenon in that way would anticipate intensive tectonics at the end of the triassic with the consequence that the lack of sedimentation would last until the late tithonian. such a hiatus there has not been substantiated. moreover, the origin of ophiolites, accompanied by younger magmatic-sedimentary rocks in the same area, argues in favour of intensive tectonics during the jurassic and the early cretaceous. besides, the triassic in question does not necessarily belong to the same tectonic unit as the triassic which constitutes the overlying nappe. some other lower cretaceous outcrops also indicate basinal sedimentation (with pelagic influences). such is the “oπtrc formation” in mt. ivanπëica described by zupani» et al. (1981). it overlies the afore mentioned tithonian-valanginian pelagic deposits. the formation consists of calcarenites, sandstones, marly shale, and deposits with radiolaria and spicules. the calcarenites frequently show silicification and recrystallization phenomena. the authors concluded that the part of the basin within the mt. ivanπëica area originated upon the continental crust. analogous relationships also occur at mt. æumberak (babi∆, 1974). moreover, correlation is assumed with the vranduk area in bosnia belonging to the bosnian zone (defined by aubouin et al., 1970), which displays essential differences in sediments beginning with the late triassic, and continuing during the jurassic and cretaceous. the zone may be followed in montenegro. in western serbia obradovi∆ & vasi∆ (1996, p. 191) speak of “isolated bedded series” with radiolarites of different ages within various complexes. analogous deposits outcrop even in albania, however not as a continuous zone but as localfig. 3 simplified main tectonic units in the mountains medvednica and kalnik; basic data from ©iki∆ (1995) and ©imuni∆ (pers. comm.), reinterpreted: 1) uppermost nappe; 2) s u p r a d i n a r i c u m (with possible small dinaric outcrops) disturbed by strong interior tectonism; 3) pelagic deposits and formations with pelagic influences (interpreted as epiadriaticum); 4) neogene and quaternary cover; 5) place of graphical shortening of the terrain. 89herak: tectonic interrelation of the dinarides and the southern alps ized “strange” bodies within the mirdita zone. all this suggests that these deposits with pelagic elements are tectonically emplaced within heterogeneous areas. similar heterogeneity has been found even in other morphotectonic units like the north karavanke alps (mio» & ©ribar, 1975), and in the outer dinarides. the latter were discussed by many authors (cited in herak, 1993). the age of dispersed pelagic deposits within the outer dinarides range from the triassic (outcrops in the budva zone, and in the slovenian trough) to the late cretaceous, with a predominance of upper jurassic outcrops. at the margin towards the inner dinarides even palaeogene outcrops occur. they all require a common provenance influenced by the same open sea environment. the lack of both intrusives and metamorphic rocks means that the distribution area of pelagic components was outside the active orogenic realm. therefore, their recent position can only be explained by entangled tectonics, discussed later. 2.5. oceanic megaenvironment the origin of a belt with oceanic components started within the area most often called the inner dinarides. according to gu©i∆ & babi∆ (1972, p. 336), the lithology and fossil contents of the fragments in the senonian breccia in mt. medvednica “show that the norian-rhaetian limestones had been deposited in a very shallow sea, whereas the liassic sediments had originated in a considerably deeper and quiet marine environment”. it is important to mention that on the northwestern slope of mt. medvednica a tectonically delimited, narrow upper triassic dogger limestone zone, partially dolomitized and recrystallized, is present (©iki∆, 1995). this means that, due to tectonic forces, two major environments have been brought close to one another. this fact requires additional investigation, as pointed out by ©iki∆ (1995, p. 14). for our purpose, it seems acceptable that, in the area where the tectonic dynamics later increased, the deepening within the triassic-liassic carbonate platform started not earlier than the end of the lias. consequently, the above mentioned, tectonically delimited pelagic limestones with chert of upper triassic age (halami∆ & gori»an, 1995; ©iki∆, 1995) should be “strange” in the areas where they are outcropping. the oceanic opening made possible the uplift of ultramafic rocks. the isolated outcrops have been found in mt. medvednica and in mt. kalnik, secondarily emplaced into cretaceous clastics. they are also present in some deep bore-holes north-eastward of mt. medvednica (©imuni∆ & pami∆, 1989; ©iki∆, 1995; pami∆, 1997). furthermore, a magmatic-sedimentary complex originated, composed of clastics and magmatic rocks: gabbro, diabases, spilites, etc. (crnkovi∆, 1963). as to the origin of the adjacent tisia, there are different opinions discussed in numerous papers (see: cloetingh et al., 1993). later, szederkeny fig. 4 simplified tectonic map of the eastern part of mt. æumberak (with the area of samobor), supplemented by j. bukovac: 1) uppermost nappe; 2) s u p r a d i n a r i c u m (with possible small dinaric outcrops); 3) pelagic deposits and formations with pelagic influences (interpreted as e p i a d r i a t i c u m ); 4) neogene and quaternary cover. 90 geologia croatica 52/1 (1996) is of the opinion that during the jurassic (bathonian) the tisia fragments were broken-off the southern margin of the variscan europe and after a complicated drifting, accompanied by rotation, came to their present tectonic position. in this case, the general platform area split into two branches. one is nowadays extended in the mid-transdanubian unit, bükk unit, etc., the other remained southward of the tisia. however, general agreement does not yet exist. anyhow, the oceanic formations were subducted northward under the platform elements, disintegrated them and, possibly, in a latter phase even obducted upon the slavonian part of the tisia (in contrast, matej et al., 1997, assume the subduction of tisia). during the oceanic dynamics metamorphic rocks (greenschists, etc.) were formed (belak et al., 1995a, b). analogous rocks have been found at places outside of our area, e.g. anchizonal metamorphism has been described in hungary in the mid-transdanubian unit. berczi-makk et al. (1993, p. 280) accepts the opinion that it presumably belongs “to a nappe unit of lower position” (i.e., to the s u p r a d i n a r icum, s. str., as it will be treated in this paper). tectonic consolidation processes, approximately at the beginning of the turonian interrupted the tectonic dynamics, responsible for the origin of the magmaticsedimentary complex. the deposition was influenced not only from the open sea, but also from the near-shore and land surfaces due to oscillation of basin bottom depth with changes of depositional environments, followed by subduction processes within the crust. all this changed the future sedimentation processes, which included conglomerates, sandstones, siltites, shales, rudist bioherms, platy limestones with globotruncanids, turbidites (with slope and bottom influences), etc. they are either in superposition or represent only lateral facies. the true relationships are difficult to explain due to subsequent tectonic disturbances. 2.6. predominance of flysch deposits from the senonian the “continental” and “oceanic” troughs were not so well delimited being narrowed due to subduction and bottom uplift. the transgression upon the adjacent land surfaces is often mentioned because flysch elements also overlie different platform surfaces. despite the interfingering with other facies, the predominance of the flysch in the time span from the maastrichtian to the palaeocene is evident (crnjakovi∆, 1981; devidé-nedĕla et al., 1982; bukovac, 1988; marin»i∆ et al., 1995; ©iki∆, 1995, etc.). 2.7. final tectogenetic consequences after the palaeocene continental subduction processes caused piling up and squeezing of different tectonic units, emplacement of granites, etc. afterwards, uplift occurred, followed by oligocene and neogene volcanism, tilting, strike-slip faulting, rotation, and, possibly, slow subduction and/or obduction. however, these events are not the topic of this paper. 3. tectonic evolution and classification the recent general characteristic of the area under discussion is intensive fragmentation of the previously described lithostratigraphic complexes. they have been disturbed by continental (a) subduction, oceanic (b) subduction, then by more or less vertical movements connected with gravitational displacements, and finally by erosion. according to the presented lithostratigraphy, the main events should be the following. before the late triassic, the major events were more or less uniform over the whole area, only displaying interior differentiations, sometimes of a high degree, but not specific enough to be used as diagnostic features in recognizing single well defined megatectonic units. at the beginning of the late triassic, the new major differentiation started. according to the afore mentioned lithostratigraphic sequences and their position between two carbonate complexes visible at many places, a labile (“miodynamic”) continental trough originated, being connected with the open sea. it enabled the open sea to influence the platform areas. the first deposits in this trough were late triassic pelagic sediments (limestones, cherts, etc.). the longitudinal distribution of their outcrops suggests an adequate (longitudinal) common “furrow”. it remains to be seen if it was within the carbonate platforms (herak, 1986, 1991, 1995, 1997, etc.) or within the oceanic realm itself, at the oceanic margin of the platform (aubouin et al., 1970). the latter opinion was common before the mobilistic concept was introduced. however, there are still many adherents (e.g., pami∆ et al., 1998). my concept is based on the fact that at several places the pelagic deposits are emplaced between two carbonate platform units (budva zone, una spring area, slovenian trough, etc.) which would be impossible if the “furrow” were adjacent to the oceanic realm. initially, the deposition was confined to the “furrow” itself, then the surfaces widened upon the platform margins, lagoons and basins of clastic deposition. after the lias, within the northern (northeastern) part of the platform a new deep oceanic trough was formed, being characterized by “eudynamic” processes during the jurassic and a larger part of the cretaceous. later on, the events in all labile areas were characterized predominantly by clastic deposits not only within the basins but also upon the adjacent platforms. according to the mentioned interrelationships, it is obvious that the reconstruction of single major tectonic zones is very difficult. however, this may be attempted, taking into account their composition and recent position. it is possible to distinguish several homogenous nappe units. they will be differently named in order to 91herak: tectonic interrelation of the dinarides and the southern alps distinguish them from the morphotectonic entities (outer dinarides, inner dinarides, southern alps, midtransdanubian zone, etc.), which are usually heterogeneous, composed of elements of two or more subducted (underthrusted) homogeneous units. as the names are a question of convention, the possibility is open for new proposals if they can be supported by better reasons. 3.1. the uppermost nappe (u) the overlying components of the region under discussion (figs. 1-4, u) form a nappe composed predominantly of triassic dolomites with some limestones, accompanied by lower triassic clastics including wellbedded limestones, as well as by upper palaeozoic molasse deposits (which do not derive from the inner dinarides). they are characterized by west-east, or southwest-northeast extension. the nappe is disintegrated and it comprises elements which have been described as the pannonian nappe (miladinovi∆, 1981, and earlier), as well as the sava nappe (mio», 1981, and earlier), or the inverse basement of the inner dinarides (herak, 1991) as a part of the s u p r a d i n a r i c u m . recent additional data (©iki∆, 1995) justify the tectonic distinction of this uppermost nappe deriving outside the dinaric realm (s. str.), i.e., from the southern alpine area, emplaced on the northern side of the oceanic trough (s u p r a d i n a r i c u m , s. str.). this nappe overlies not only the oceanic s u p r a d i n a r i c u m , but also parts of jurassic and cretaceous carbonate rocks of the dinaric carbonate platform (d i n a r i c u m), mostly in the form of klippen. the final emplacement may be at least partly caused by gravitation. at this point, it is necessary to note that some triassic and palaeozoic deposits may not belong to the uppermost nappe but to dinaridic major units as their direct basement. therefore, the utmost care is required in interpretation of the tectonic position of different triassic and palaeozoic outcrops. 3.2. the supradinaric nappe (supradinaricum , s. str., s) this nappe (figs. 1-4, s) comprises the oceanic part of the s u p r a d i n a r i c u m (s. l.), overlain by the uppermost nappe. the nappe is characterized by formations originated as a consequence of “eudynamics” from the lias to the turonian. in the senonian, differentiation increased under pelagic and terrestrial influences. simultaneous uplifts widened the influences of this basin upon adjacent platform margins, in the form of extensions of flysch deposits (marginal flysch) which hide the boundaries between the basin and the platforms. therefore, only flysch deposits, which are tectonically connected with oceanic formations, belong to this nappe. the rest of it (the marginal epiplatform flysch) is to be treated together with the next tectonic megaunit (d i n a r i c u m). the vardar elements are also included in the s u p r a d i n a r i c u m . however, their frame exceeds the frame of the vardar zone as defined by kossmat (1924). the western extension of the s u p radinaricum is covered by the uppermost nappe. 3.3. the dinaric nappe (dinaricum, d) at the southern (southwestern) side, the rocks of the dinaric carbonate platform (figs. 1 and 2, d) bordered the oceanic belt (s u p r a d i n a r i c u m , s. str.). as a major tectonic unit, it is called dinaricum and it underlies the supradinaric nappe. within the d i n a r i c u m s e v e r a l “strange” outcrops of pelagic deposits have been found. their origin and tectonic position were repeatedly discussed (citations in herak, 1993). in the contact area of the s u p r a d i n a r i c u m and d i n a r i c u m , including the marginal flysch (with some karstifications in the basement), the nappe relations are obvious (premru et al., 1977; herak, 1986; bukovac, 1988). consequently, “la sous-zone prékarstique” (blanchet et al., 1970) is also included into this megaunit. previously, the contact zone of the dinaric platform and oceanic formations was treated as a “flexion” or “bending” zone, making a slope of the platform towards the basinal complexes including magmatites. it was supposed that this zone existed probably since the triassic, representing “the adriatic microplate toward the tethys ocean” (dimitrijevi∆, 1982, p. 11). however, it is obvious that this contact zone was created as a consequence of two events. the first, was the opening of the ocean after the lias (more or less vertical contacts). the second was continental subduction during the palaeogene, when the dinaric carbonate platform, together with the overlying marginal flysch, was subducted under the basinal “magmatic-sedimentary” complex (s u p r a d i n a r i c u m ) and even under the uppermost nappe. the corresponding contacts are inclined. the opposite margin of this megaunit, together with the underlying “strange” pelagic outcrops, are discussed below. 3.4. the interplatform megaunit (epiadriaticum , e) the range of the isolated outcrops of pelagic and basinal deposits without ultramafic and mafic intrusions range from the upper triassic to the upper cretaceous, and are to be found as well in the outer as in the inner dinarides (figs. 1-4, u). their distribution is extremely difficult to explain in a generally acceptable way. the continuous outcrops extend only in the budva-krastapindus zone on the southeastern side and in the slovenian trough on the northwestern side. between these areas, numerous tectonically delimited outcrops may indicate that their interconnection could be traced beneath the nappes mentioned earlier. in such a case even the bosnian zone (aubouin et al., 1970) may be connected with the budva-krasta-pindus zone below the d i n a r i c u m due to continental subduction. the indications of such a connection were noticed earli92 geologia croatica 52/1 er. medwenitsch (1964, in siko©ek & medwenitsch, 1965) distinguished the subdinaricum which should consist of budva, mirdita and raduπa elements together with the central ophiolites. their extension is supposed to be beneath the carbonate dinarides. in this way, typical inner dinaric elements (mirdita, raduπa, central ophiolites), which normally overlie the outer dinarides, were connected with the budva zone which underlies them and now can be interpreted as a subducted unit. on the contrary, pami∆ (1993, etc.), tried to connect the bosnian zone with the budva zone (united with the mirdita zone) upon the surface lithologic analogies. however, the main problem, concerning all the pelagic outcrops, is that they are delimited to small areas, which are dispersed and tectonically encircled with deposits of different provenance, belonging to various morphostructural units. for instance, the deposits in question in western slovenia are in contact with the dinaric platform, the julian alps and the “sava folds” (= sava nappe sensu mio», 1981). in mt. æumberak, mt. medvednica, mt. ivanπëica and mt. kalnik pelagic outcrops occur within “magmatic-sedimentary” formations and, exceptionally, within platform elements. likewise, the pelagic elements of the bosnian zone (aubouin et al., 1970) are mostly in tectonic contact with different inner dinaric rocks, including the ophiolites. also there are localities in western serbia (obradovi∆ & vasi∆, 1996), as well as in albania, where localized “strange” bodies (rubik complex, kalur cherts, and lumi i zi sections) are distributed as isolated bodies within the mirdita zone (carosi et al., 1996; marcucci & prela, 1996). besides, numerous jurassic and less numerous cretaceous isolated pelagic outcrops, often in visible tectonic contacts with shallow-water carbonate rocks, are widespread within the dinaric carbonate platform in slovenia, croatia, hercegovina and montenegro, while the budva zone is overthrust upon the adriatic carbonate platform (herak, 1986, with older citations). these facts and opinions require comparison with other possible alternative explanations, to determine which is the most convincing. the first possibility would concern the model with facies differentiation. in that case, tectonic contacts with adjacent facies would be uncommon. besides, it is impossible to assume that similar pelagic environments would prevail at the same time within a basin, which is influenced by magmatic activity and on a stabilized carbonate platform without influences from a common source of the pelagic components. comparing recent and fossil global radiolarian localities, de wever & baudin (1996) came to the following conclusions: (a) “distal basinal or oceanic environments are often optimal sites for the preservation of siliceous and lipid-rich organic material derived from plankton” (p. 310); (b) “the long held assumption of a relationship between abundance of radiolarians and volcanic processes is largely erroneous” (p. 311). even in the case when the basins are separated from the ocean by a platform, they have to be partially open to the ocean (p. 313). however, due to oscillations the deposition itself, characterized by pelagic fossils, occurred in various depressions, i.e. even upon the platforms (in lagoons). the only condition is in the interference with the open sea (in our case the eastern tethys). consequently, the pelagic components had neither oceanic nor platform characteristics. within the derivation trough itself the pelagic column seems to be more or less complete. upon both the adjacent marginal parts of the carbonate platforms the range and extension varied. the peripheral common boundary (at different horizons) has been characterized by the transition of pelagic deposits to carbonate shallow-water sediments. such exposures are, in a tectonical sense, part of the platforms, while, below the dinaricum a consistent tectonic complex is to be supposed. the fragmental exposures require an explanation introducing either erosion of a common overlying and tectonically disintegrated megaunit or by numerous localized uplifts of a consistent major unit outcropping in tectonic windows which were afterwards slightly disturbed, i.e. fractured, tilted, and eroded. the erosion as a main factor, which would disintegrate a homogeneous pelagic major unit, cannot be accepted, because, in that case, this unit should primarily cover the deposits of different ages and environments. such a case is improbable even when there were no tectonic contacts of single outcrops with adjacent deposits. however, in many cases the contacts are distinct. at some localities younger deposits outcrop through the older ones, thus favouring allochthony. the relationships within carbonate terrains are characterized by a very important phenomenon: the rocks of the adriatic carbonate platform primarily and tectonically underlie the pelagic deposits. at the same time, the d i n a r i c u m overlies the pelagic distal deposits (together with the underlying rocks of the adriatic platform) suggesting nappe relationships. the participation of pelagic deposits in the dinaricum is not obvious due to subductional contact. in the subduction process within the continental crust, the ductile deposits were a detachment level, making possible long-rate continental subduction even under the “magmatic-sedimentary” formations, indicating that the dispersed pelagic outcrops within them are tectonic windows. such a concept respects the dispersion of pelagic and other deposits with open sea influences within the belts of different provenance and their contacts with platform and basinal formations. the relationships of platform and pelagic deposits are still hidden due to nappe relationships. the interior reconstruction of their allochthonous disturbances are omitted. 3.5. the adriatic nappe (adriaticum, a) the next lower tectonic major unit consists predominantly of carbonate rocks with some pelagic sediments 93herak: tectonic interrelation of the dinarides and the southern alps and flysch. it is extended on the southwestern side of the overlying e p i a d r i a t i c u m (fig. 2, a). there are also some detached bodies of the d i n a r i c u m overlying the a d r i a t i c u m (possibly, due to younger gravitational displacements). the differences between them are difficult to establish, and require detailed analyses and regional correlations. recently, drobne & trutin (1997) palaeontologically confirmed the existence of a tectonic window of the marginal part of the a d r i a t i c u m t h r o u g h the d i n a r i c u m at buniê in the lika. bla©kovi∆ (1999) proposed a major tectonic classification based on the a d r i a t i c u m, e p i a d r i a t i c u m and d i n a r i c u m f o r purpose of oil prospection. romandi∆ & aljinovi∆ (1999) easily recognized the a d r i a t i c u m b e n e a t h the d i n a r i c u m in strongly disturbed sedimentary sequences, with cumulative thickness of up to 17 km, using geoelectric and palaeomagnetic methods. the a d r i a t i c u m is delimited by the e p i a d r i a t i c u m on one side and by (?)ionian deposits on the other. longitudinally it continues toward the southeast into the gavrovo-tripolitza domain. sporadically, it occurs within the d i n a r i c u m as tectonic windows. remarkable is also the hercegovinian half-window. 3.6. ?the ionian underthrust (?ionicum, i) the insular region of the adriaticum is underlain by cretaceous-palaeogene deposits (lawrence et al., 1995), possibly belonging to the ionian basin, and subducted under the adriaticum (fig. 2, i). this fact may justify the distinguishing of the adriatic and apulian platforms. 4. conclusions to avoid some discrepancies in the interpretation of the alpino-dinaridic realm in a “geosynclinal” way, one of the posibilities is to follow the partially emended concept of continental subductions as accompanying process of oceanic subduction, based upon new lithostratigraphic and structural notions previously cited. the approach to the subduction mechanism encounters great difficulty due to the fact that the traces of the oceanic subduction are quite hidden. only the presence of restricted outcrops of ultramafic rocks (©imuni∆ & pami∆, 1989; pami∆, 1997), secondarily emplaced into cretaceous deposits, testifies such a process. therefore, they do not reflect primary relationships which would define their origin and later tectonic displacements. even the essential problem related to our part of tethys is not obvious; it concerns the question of whether we are dealing only with a branch of tethys or if there was a connection with the penninic belt below the southern alps and the austroalpine nappes. also, the time of the tectonic emplacement of the slavonian mountains (as a part of tisia) is still under discussion. the only certain geotectonic phenomena are the consequences of continental subductions. their traces are preserved within all the major facies, indicating a general northward (northeastward) movement (caused by the movements in the asthenophere). all the complexes of the outer and inner dinarides behaved according to their constitution, being either brittle or ductile. anyway, the rate of the disturbances suggests the existence of weak zones at several levels, which made a strong allochtonous imbrication possible. the continental subductions were preceded by very complex dynamics, and have been followed by uplift of the area (vertical faulting), tilting, possible additional subduction and obduction, rotation, and often neglected gravitational displacements. the time relations of the tectogenetic process are relatively easily distinguished. 1. during the variscan orogeny, vast continental surfaces originated, upon which, later, intensive deposition of terrigenous fragments occurred. however, in that time the continental crust was not completely stabilized. rifting and magmatic processes in the middle triassic (and at the beginning of the late triassic) were renewed, and accompanied by andesitic extrusions (tardy-variscan dynamics). this disquiet was relatively short and final, and it prepared the basis for vast and temporally extensive sedimentation of carbonate platform deposits. in the upper triassic an oscillating interplatform trough was formed. it remained directly connected with the open sea, from which pelagic components were supplied during the whole mesozoic era. the oscillations within the trough caused periodic ingressions of pelagic deposits upon the adjacent platforms, especially in the late jurassic and the late cretaceous. 2. north of the interplatform trough, after the lias, the opening of the ocean (including our western branch) occurred with simultaneous extrusions of already consolidated mantle rocks (ultramafites). so, the “miodynamics” and “eudynamics” were contemporaneous with mutual influences in their final phase. after the extrusions of the mantle rocks (peridotites, serpentinites), the equilibrium was disturbed and northward movements of lithospheric complexes were initiated (as a consequence of adequate dynamics in the asthenosphere). all this resulted in oceanic subduction and the consuming of subducted material, while the more resistent ultramafites remained on the surface, submitted to further disturbances. 3. the asthenospheric northward movements were not only localised under the oceanic lithosphere, but were also active under the continental part, including the trough between the adriatic and dinaric platforms. the influence was different upon the platform surfaces in comparison with the oscillating trough, in which continental subduction started. therefore, the trough narrowed and the sea level rose, with the ingression of pelagic material upon 94 geologia croatica 52/1 the marginal platform areas, overlying platform formations and interfingering with them. 4. the oceanic trough was, in the late jurassic and the early cretaceous, still a place of intensive “eudynamics” accompanied by strong magmatism and low to medium-grade metamorphism. the closure of the trough, approximately in the middle cretaceous, was followed by deposition of clastics accompanied by small reefs, platy limestones, and by flysch deposits. at that time, there were no sharp boundaries of the sedimentary basins within the frame of the dinaridic part of the tethys. 5. due to the closure of epicontinental and oceanic belts, the crust generally coalesced and afterwards behaved more or less as a single major unit composed of rigid and weak domains. this fact determined the future behaviour in respect to the northward movement in the asthenosphere, which continued. the multiple continental subductions were influenced by ductile horizons. in this way a complex allochthonous structural pattern has originated. along the interplatform trough, the subduction was most intensive, resulting in the carbonate rocks with the flysch of the adriatic platform (a d r i a t i c u m) underlying not only the pelagic elements (of epiadriatic provenance), but elsewhere are also directly overlain by the carbonate rocks of the dinaric platform (d i n a r i c u m). the d i n a r i c u m has been subducted under the oceanic formations (s u p r a d i n a r icum, s. str.) which underlie palaeozoic and triassic platform elements of the uppermost nappe. moreover, in the frames of the major nappes imbrication is also present. delimitation and gradation of tectonic units is difficult due to the fact that parts of pelagic and flysch deposits primarily overlie platform margins, and are, in the tectonic sense, only parts of the platform nappe units. along the major contact zones, the underthrusting character of contacts is obvious, though not necessarily equal to one another. then, subduction process increased towards the west (northwest) and, therefore, the zones wedge out. in this way the dinaric strike (se-nw) was finally established. only the elements of the uppermost nappe have not been essentially influenced, and so the difference in strike between this nappe and the dinaridic structural units (nappes) could be explained. such a dynamics lasted approximately until the end of the oligocene and, thus, the basis for the neogene indentation process was prepared. the consequences of the process itself have been interpreted in several papers (e.g., ratschbacher et al., 1991), though the moving forces were not well defined. according to this proposal, they should be represented by continental subductions. 6. simultaneously, in the main alpine and carpathian domains, the subductions were directed generally toward the south. therefore, our region was squeezed and the thickness of sedimentary complexes increased, not only due to piling up of subducted units but also due to the rise of the cretaceouspalaeogene s-granites, final volcanism, etc. 7. the concentrated thermal “diapirism” was distributed within all the tectonic units, and in this way numerous tectonic windows originated, predominantly of the ductile flysch and pelagic deposits. at such places the chaotic carbonate breccias on the northern slope of mt. medvednica (“horvatove stube”, pronjak), as well as in mt. kalnik and mt. ravna gora, have been interesting to many authors (e.g. babi∆ et al., 1973; ©imuni∆ et al., 1993; prtoljan et al., 1995), but a final explanation has not yet been found. their emplacement is characterized by tectonic contacts with the adjacent rocks. the age of the fragments belong to different horizons of the mesozoic, with a matrix of campanian age. ©imuni∆ et al. (1993, p. 614) assume that the upper boundary of these “exotic breccias” is post-palaeocene, and suggest “that they might have been originated along subduction zones”. it could be added that also localized rise of parts belonging to different subducted nappes contributed to the genesis of the breccias, making in fact the (additionally disturbed) tectonic windows. i am conscious that such an unconfirmed opinion might be considered as too courageous, but it should be taken into account in future discussions. 8. the mentioned vertical diversification was intensifi ed during the neogene, and caused disintegration, tilting, rotation and gravitational displacements of parts of the nappes. therefore, fragments with different vergencies are to be found even upon neogene sediments. the process itself is considered as very complicated (possibly combined with slight subductions), and an explanation exceeds the topic of this paper. 9. the proposed model can be understood on the basis of the mobilistic interpretation of geotectonic problems. the assumption of continental subductions helps to explain not only major structures but also “strange”, “uncommon”, “isolated”, and “exotic” phenomena, as single constituents of major tectonic units, within logical, though not anticipated structural frameworks. 10. due to a nappe system, it is necessary to distinguish not only the previously discussed homogeneous tectogenetic units (uppermost nappe, supradinaricum , s. str., d i n a r i c u m, e p i a d r i a t i c u m , a d r i a t i c u m a n d (?)ionian underthrust) but also some more or less individualized morphotectonic complexes, e.g., the adriatic area, high karst belt, outer dinarides, inner dinarides, the pannonian basin, etc. to this category of terms also belong the mid-transdanubian zone, zagreb zone, and “sava folds”. they all are characterized by a heterogeneous, composite 95herak: tectonic interrelation of the dinarides and the southern alps constitution terminated during neotectonic dynamics, and are used in the regional geology and geomorphology. 11. i hope that the intention of this paper to explain the tectonic setting of the alpino-dinaridic realm in a mobilistic sense may be generally acceptable base for further discussions. therefore, the concept may not be considered as final. many pecularities remain open to further confrontations, based upon additional, more accurate (confirming or emending) data. acknowledgements the preparation of the manuscript required additional discussions of some elementary data with experts of different research fields, e.g., with ljubomir babi∆, stjepan bahun, mirko belak, josip bukovac, ivan gu©i∆, domagoj jami»i∆, vladimir jelaska, vladimir majer, pero mio», jakob pami∆, branko soka», antun ©imuni∆, marko ©parica, ivo veli∆, etc. the drawings have been executed by miroslav kladni»ki. to all of them i express my sincere gratitude. 5. references aubouin, j., blanchet, r., cadet, j.-p., celet, p., charvet, j., chorowicz, j., cousin, m. & rampnoux, j.-p. (1970): essai sur la géologie des dinarides.bull. soc. géol. de france, 12, 1060-1095. babi∆, lj. (1973): bazenski sedimenti gornjeg titona i valendisa zapadno od bregane (upper tithonian to valanginian basinal sediments west of bregana).geol. vjesnik, 26, 11-27. babi∆, lj. (1974): razdoblje otriv-cenoman u æumberku: stratigrafija, postanak sedimenata i razvoj prostora (hauterivian to cenomanian time in the region of æumberak, northwestern croatia: stratigraphy, sediments, paleogeographic, paleotectonic evolution).geol. vjesnik, 27, 11-33. babi∆, lj. (1975): kondenzirani lijas medvednice i ivanπëice i njegovo znaëenje za interpretaciju paleogeografskog razvoja unutarnje dinarske regije (condensed liassic sedimentation on mt. medvednica and mt. ivanπëica northern croatia and its significance for the interpretation of the paleogeographic evolution of the inner dinaric belt).geol. vjesnik, zagreb, 28, 11-18. babi∆, lj. (1980/81): the origin of “krn breccia” and the role of the krn area in the upper triassic and jurassic history of the julian alps (postanak “breëe krna” i uloga predjela krna u povijesti julijskih alpa u gornjem trijasu i juri).vesnik zav. geol. geofiz. istraæ., (a), beograd, 38-39, 59-75. babi∆, lj. & zupani», j. (1973): najmlaa jura i najstarija donja kreda u ivanπëici (uppermost jurassic and early cretaceous deposits on mt. ivanπëica northern croatia).geol. vjesnik, 26 (1972), 267272. babi∆, lj. & zupani», j. (1978): kossmatovi “æeleznikarski vapnenci i dolomiti” i “zaliloπki krovni πkriljavci” u predgorju julijskih alpa; podaci o stratigrafiji, facijesu i paleogeografskom znaëenju (kossmat’s “kalke und dolomite von eisnern” and “dachschiefer von salilog” in the julian prealps: data about stratigraphy, facies and paleogeography).geol. vjesnik, 30/1, 21-42. babi∆, lj., gu©i∆, i., & devidé-nedĕla, d. (1973): senonski krπnici na medvednici i njihova krovina (senonian breccias and overlying deposits on mt. medvednica northern croatia).geol. vjesnik, 25 (1971), 11-27. belak, m., pami∆, j., kolar-jurkov©ek, t., pecskay, z. & karan, d. (1995a): alpinski regionalnometamorfni kompleks medvednice sjeverozapadna hrvatska.1. hrv. geol. kongres (opatija, 1995), zbornik radova, 1, 67-70, zagreb. belak, m., sremac, j., crnko, j. & kolarjurkov©ek, t. (1995b): paleozojske stijene niskog stupnja metamorfizma na jugoistoënoj strani medvednice (sjeverozapadna hrvatska).1. hrv. geol. kongres (opatija, 1995), zbornik radova, 1, 7174, zagreb. berczi-makk, a., haas, j., ralisch-felgenhauer, e., & oravecz-scheffer, a. (1993): upper paleozoic-mesozoic formations of the midtransdanubian unit and their relationships.acta geol. hungar., 36/3, 263-296. blanchet, r., cadet, j.p. & charvet, j. (1970): sur l’existence d’unités intermediaires entre la zone haut-karst l’unité du flysch bosniaque, en yougoslavie: la sous-zone prékarstique.bull. soc. géol. de france, 12, 227-236. bla©kovi∆, i. (1999): subsurface tectonic relations a basis for determination of the zones of petroleumgeological prospectivity.working materials, 2nd intern. symposium of petroleum geology, croat. acad of sci. and arts, faculty of mining, geology and petroleum engineering and ina, 133-145, zagreb. bukovac, j. (1988): tectonics of the contact zone of the dinaricum and supradinaricum in the area of krnjak-bariloviê-karlovac, croatia, yugoslavia (tektonski odnosi u kontaktnoj zoni dinarika i supradinarika u podruëju krnjak-bariloviê-karlovac, hrvatska, jugoslavija).acta geol., 18/1, 1-12, zagreb. buser, s. (1977): osnovna geoloπka karta sfrj 1:100.000. list celje l33-67.geol. zavod ljub96 geologia croatica 52/1 ljana (1972-1976), savezni geoloπki zavod, beograd. buser, s. (1989): development of the dinaric and the julian carbonate platforms and of the intermediate slovenian basin (nw jugoslavia).mem. soc. geol. it., 40 (1987), 313-330. carosi, r., codra, a., marroni, m. & mustafa, f. (1996): deformation history of jurassic kalur cherts from the mirdita nappe, albanian ophiolites.ofiolit, 21/1, 41-45, pisa. cloetingh, s., sassi, w. & horváth, f. (eds.) (1993): the origin of sedimentary basins: interferences of the quantitative modelling and basin analyses.tectonophysics, 226, elsevier, 518 p. cousin, m. (1973): le sillon slovène: les formations triassiques, jurassiques et neocomiennes au nordest de tolmin (slovenie occidentale, alpes méridionales) et leur affinites dinariques.bull. soc. géol. france, 15/3-4, 326-338. crnkovi∆, b. (1963): petrografija i petrogeneza magmatita sjeverne strane medvednice (petrography and petrogenesis of the magmatites of the northern part of medvednica mountain).geol. vjesnik, 16 (1962), 63-160. crnjakovi∆, m. (1981): mastrihtski fliπ jugozapadnog dijela medvednice (maastrichtian flysch sediments in the southwest part of mt. medvednica).geol. vjesnik, 34, 47-61. cviji∆, j. (1924): geomorfologija.dræ. πtamparija, beograd, xxi+588 p. d e v i d é n e dĕla, d. & kochansky-devidé, v. (1990): neoschwagerinenfund in medvednicagebirge (zagrebaëka gora).rad jugosl. akad. znan. i umjetn., 449, 29-34, zagreb. d e v i d é n e dĕla, d., babi∆, lj. & zupani», j. (1982): mastrihtska starost fliπa vivodine u æumberku i kod ozlja (zapadna hrvatska) na temelju planktonskih foraminifera (age maestrichtien du flysch de vivodina dans le æumberak et des environs d’ozalj en croatie occidentale yougoslavie).geol. vjesnik, 35, 21-36. de wever, p. & baudin, f. (1996): palaeogeography of radiolarite and organic-rich deposits in mesozoic tethys.geol. rundschau, 85, 310-326, berlin. diener, c. (1903): bau und bild der ostalpen und des karstgebietes.bau und bild österreichs, wien, 2, 1-328. dimitrijevi∆, m.d. (1982): “pregib”, gledan mobilistiëki (“flexion zone” a mobilistic viewpoint).radovi znan. savjeta za naftu jugosl. akad znan. i umjetn., a, 10, 7-11, zagreb. drobne, k. & trutin, m. (1997): alveolinas from the buniê section.geol. croatica, 50/2, 215-223. –ur–anovi∆, æ. (1973): o paleozoiku i trijasu medvednice (zagrebaëke gore) i podruëja dvora na uni na temelju konodonta (about the paleozoic and triassic of medvednica mountain and the area near dvor na uni on the basis of conodonts).geol. vjesnik, 25 (1971), 29-49. gorjanovi∆-kramberger, d. (1907): geologija gore samoborske i æumberaëke.rad jugosl. akad. znan. i umjetn., 120 (matem.-prir, razred, 18), 1-82, zagreb. grad, k. (1961): obavestilo o raziskavah krednih sedimentov v posavskih gubah (note on the investigation of cretaceous sediments in the sava folds).geologija, 6 (1960), 313-315, ljubljana. gu©i∆, i. & babi∆, lj. (1972): die mikrofazies und mikrofauna der obertrias und des lias des medvednica gebirges (nordkroatien).mitt. ge. geol. bergbaustud., 21, 327-340, innsbruck. haas, j., kovács, s., krystyn, l. & lein, r. (1995): significance of late permian-triassic facies zones in terrane reconstruction of alpine north pannonian domain.tectonophysics, 242, 19-40. halami∆, j. & gori»an, ©. (1995): triassic radiolarites from mts. kalnik and medvednica.geol. croat., 48/2, 129-146. herak, m. (1986): a new concept of geotectonics of the dinarides (nova koncepcija geotektonike dinarida).acta geol., 16/1, 1-42, zagreb. herak, m. (1991): dinaridi mobilistiëki osvrt na genezu i strukturu (dinarides mobilistic view of the genesis and structure).acta geol., 21/2, 35-117, zagreb. herak, m. (1993): additional considerations on the epiadriaticum, outer dinarides.geol. croat., 46/1, 165-168. herak, m. (1995): koncepcijski doseg geologije hrvatske (conceptional scope of the geology of croatia).1. hrv. geol. kongres (opatija, 1995), zbornik radova, 1, 25-33, zagreb. herak, m. (1997): croatia.in: moores, e.m. & fairbridge, r.w. (eds): encyclopedia of european and asian regional geology. chapman & hall, london, 155-160. herak, m., jami»i∆, d., ©imuni∆, a. & bukovac, j. (1990): the northern boundary of the dinarides (sjeverna granica dinarida).acta geol., 20/1, (prir. istraæ., 60), 5-27, zagreb. herak, m. & ©kalec, d. (1967): vapnenaëke alge u permu samoborskog gorja (kalkalgen im perm des samoborer gebirges).geol. vjesnik, 20, 37-40. jami»i∆, d. (1983): strukturni sklop metamorfnih stijena krndije i juænih padina papuka (structural fabric of the metamorphosed rocks of mt. krndija and 97herak: tectonic interrelation of the dinarides and the southern alps the eastern part of mt. papuk).geol. vjesnik, 36, 51-72. jenko, k. (1944): geoloπki rad na listu samobor 1:75000.vjesnik hrv. dræ. geol. zav., 2/3, 19-23, zagreb. jurkov©ek, b., ©ribar, lj. & kolar-jurkov©ek, t. (1990): pelagiëke jurske in kredne plasti v zahodnem delu julijskih alp (pelagic jurassic and cretaceous beds in the western part of the julian alps).geologija, 31-32 (1988-89), 285-328, ljubljana. ki©pati∆, m. (1899): nastavak bosanske serpentinske zone u hrvatskoj.rad. jugosl. akad. znan. i umjetn., 139 (matem.-prir. razred, 27), 44-73, zagreb. koch, f. (1924): geotektonische beobachtungen in alpino-dinarischem grenzgebiete.zbornik radova posv. jovanu cvijiêu,341-358, beograd. kossmat, f. (1924): geologie ser zentralen balkanhalbinsel; mit einer übersicht des dinarischen gebirgsbaues. die kriegsschauplätze 1914-1916.bornträger, berlin, v+198 p. lapajne, v. & ©ribar, lj. (1973): zgornjokredni sedimenti na obmoëju posavskih gub (upper cretaceous deposits in the sava folds).geologija, 16, 237-244, ljubljana. lawrence, s.r., tari-kova»i∆, v. & gjuki∆, b. (1995): geological evolution model of the dinarides.nafta, 46/2, 103-113, zagreb. marcucci, m. & prela, m. (1996): the lumi i zi (puke) section of the kallur cherts: radiolarian assemblages and comparison with other sections in northern albania.ofioliti, 21, 71-84, pisa. marin»i∆, s., ©parica, m., beni∆, j. & korolija, b. (1995): sedimenti senona u dolini mikuliê potoka.in: ©iki∆, k. (ed.): geoloπki vodië medvednice. inst. za geol. istraæ. & ina-naftaplin, 7376, zagreb. matej, s., novoselec, e. & tari-kova»i∆, v. (1997): neogene extension and compression processes in the central part of the sava depression, south pannonian basin, croatia.dynamics of the pannonian-carpathian-dinaride system, polish acad. of sci., 1091, krakow zakopane. miladinovi∆, m. (1981): pregled tektonske grae zapadnog dela jugoslavije (vue sur la téctonique des dinarides occidentales yougoslaves).geol. glasnik, 9, 89-106, titograd. milanovi∆, m. (1982): carboniferous microfossils from gorski kotar, hrvatsko zagorje and banija (karbonske mikrofosilne asocijacije gorskog kotara, hrvatskog zagorja i banije).palaeont. jugosl., 28, 1-34, zagreb. mio», p. (1975): prilog poznavanju tektonskih odnosa graniëne zone istoënih posavskih bora i dinarskog πelfa (contribution to the knowledge of the tectonic relations of the boundary zone of the eastern sava folds and dinaric shelf).2. god. znan. skup sekcije za primjenu geol., geofiz. i geokem. znan. savjeta za naftu jugosl. akad. znan. i umjetn., 223-228, zagreb. mio», p. (1981): tektonski odnosi savske navlake u sloveniji te njena veza sa πirim jugoslavenskim podruëjem (tectonic relationship of sava thrust compared to the adjacent units in slovenia and its relation with the broader yugoslav area).nafta, 32/11, 543-548, zagreb. mio», p. & ©ribar, lj. (1975): jurski skladi v severnih karavankah (the jurassic beds in the north karavanke mountains).geologija, 18, 87-97, ljubljana. mlakar, i, (1987): prispevek k poznavanju geoloπke zgradbe posavskih gub in njihovega juænega obrobja (a contribution to the knowledge of the geological structure of the sava folds and their southern border).geologija, 28-29 (1985-86), 157-182, ljubljana. mojsisovics, e. (1880): west bosnien und türkisch-croatien.in: mojsisovics, e., tietze, e. & bittner, a. (eds.): grundlinien der geologie von bosnien-herzegowina. jahrb. geol. reichsanst., 30, 1-100, wien. obradovi∆, j. & vasi∆, n. (1996): the significance of the radiolarites in the evolution of depositional basins some examples in yugoslavia.in: terranes of serbia. univ. of belgrade & serbian acad. of sci. and arts, 191-195, beograd. pami∆, j. (1993): eoalpine to neoalpine magmatic processes in the northwestern vardar zone, the easternmost periadriatic zone and the southwestern pannonian basin.tectonophysics, 226, 503-518. pami∆, j. (1997): the northwesternmost outcrops of the dinaric ophiolites: a case study of mt. kalnik (north croatia).acta geol. hungar., 40/1, 37-56. pami∆, j., gu©i∆, i. & jelaska, v. (1998): geodynamic evolution of the central dinarides.tectonophysics, 297, 251-264. peters, f.k. (1863): bemerkungen über die bedeutung der balkan-halbinsel als festland in der liasperiode.sitzungsber. akad. wiss. (matem.-naturwiss. klasse), 6-10, 418-426, wien. pilar, gj. (1882): geoloπka zapaæanja u zapadnoj bosni. iztraæivanja od 1879.rad jugosl. akad. znan. i umjetn., 65, 1-68, zagreb. premru, u. (1975): starost ponikvastih skladov (das alter der ponikva-schichten).geologija, 18, 7586, ljubljana. premru, u. (1983): osnovna geoloπka karta sfrj 1:100.000. list ljubljana l33-66.geol. zavod 98 geologia croatica 52/1 ljubljana (1969-1978), savezni geoloπki zavod, beograd. premru, u., ogorelec, b. & ©ribar, lj. (1977): o geoloπkoj zgradbi dolenjske (on the geological structure of the lower carniola).geologija, 20, 167-192, ljubljana. prtoljan, b., o©tri∆, n., fu»ek, l., veli∆, i. & ti©ljar, j. (1995): mezozojske vapnenaëke stijene u predjelu horvatove stube markov travnik.in: ©iki∆, k. (ed.): geoloπki vodië medvednice.inst. geol. istraæ. & ina-naftaplin, 137-139, zagreb. ratschbacher, l., frisch, w., linzer, h.g. & merle, o. (1991): lateral extrusion in the eastern alps; part 2: structural analysis.tectonics, 10/2, 257-271. romandi∆, s. & aljinovi∆, b. (1999): interpretation of geophysical data in sw part of dinarides.working materials, 2nd intern. symposium of petroleum geology. croat. acad. of sci. and arts, faculty of mining, geology and petroleum engineering & ina, 195-205, zagreb. salopek, m. (1914): moderna alpinska tektonika i geologija hrvatske i slavonije.glasnik hrv. prir. druπtva, 26/2, 85-109, zagreb. siko©ek, b. & medwenitsch, w. (1965): neue daten zur fazies und tektonik der dinariden.verh. geol. bundesanst., sonderheft g, 86-102, wien. sremac, j. & mihajlovi∆-pavlovi∆, m. (1983): graptoliti medvednice (zagrebaëke gore) (graptolites of mt. medvednica zagrebaëka gora).rad jugosl. akad. znan. i umjetn., 404, (razr. prir. znan., 19), 65-68, zagreb. suess, e. (1875): die entstehung der alpen.bornträger, berlin, 158 p. szederkeny, t. (1996): metamorphic formations and their correlation in the hungarian part of tisia megaunit (tisia composite terrane).in: terranes of serbia. univ. of belgrade & serbian acad. of sci. and arts, 229, beograd. ©iki∆, k. (ed.) (1995): geoloπki vodië medvednice.inst. za geol. istraæ. & ina, zagreb, 199 p. ©iki∆, k., basch, o. & ©imuni∆, a. (1978): osnovna geoloπka karta sfrj 1:100000. list zagreb, l38-80.inst. geol. istraæ. (1972), savezni geol. zavod, beograd. ©iki∆, k., basch, o. & ©imuni∆, a. (1979): osnovna geol. karta sfrj 1:100000. tumaë za list zagreb, l38-80.inst. geol. istraæ. (1972), savezni geol. zavod, beograd, 81 p. ©imuni∆, a. (1979): the deep marine development of paleozoic and mesozoic in northwestern croatia.16th european micropaleont. colloquium, 107-111, ljubljana. ©imuni∆, a. (1992): geoloπki odnosi srediπnjeg dijela hrvatskog zagorja.unpublished phd thesis, university of zagreb, 193 p. ©imuni∆, a. & he∆imovi∆, i. (1979): tektonski odnosi sjeverozapadne hrvatske ivanπëica, kalnik i ravna gora (tectonic relationships of the northwest croatia ivanπëica, kalnik and ravna gora).zbornik radova 4. god. skupa sekcije za primjenu geol., geofiz. and geokem. znan. savjeta za naftu, stubiëke toplice, 1978, jugosl. akad. znan. i umjetn., 187-198, zagreb. ©imuni∆, a. & pami∆, j. (1989): ultramafitne stijene kod gornjeg oreπja na sjeveroistoënim obroncima medvednice (ultramafic rocks on the northeastern flanks of mt. medvednica northern croatia).geol. vjesnik, 42, 93-101. ©imuni∆, a., najdanovski, j. & pami∆, j. (1993): chaotic rock-complexes, possible hydrocarbon accumulations in southwestern parts of the pannonian basin (r. of croatia).nafta, 44/11, 609616, zagreb. tornquist, a. (1918): das erdbeben von rann an der save.mitt. erdbebenkommission, n.f., 52, 1117, wien. winkler, a. (1924): über den bau der östlichen südalpen.mitt. geol. ges., 16 (1923), 1-272, wien. zupani», j., babi∆, lj. & crnjakovi∆, m. (1981): bazenski klastiti donje krede (oπtrc formacija) ivanπëice u sjeverozapadnoj hrvatskoj (lower cretaceous basinal clastics (oπtrc formation) in mt. ivanπëica (northwestern croatia)).acta geol., 11, 1-44, zagreb. manuscript received february 3, 1998. revised manuscript accepted may 28, 1999. 1. introduction the stratigraphic succession exposed in the gebel hafit area of the united arab emirates (fig. 1) ranges from eocene to miocene in age (hunting, 1979; cherif & el deeb, 1984; hamdan & bahr, 1992; anan et al., 1992; anan, 1996). basically, the lower eocene is represented by a relatively thin sequence of limestones, with marl intercalations in its upper part (rus formation), while the middle and upper eocene are represented by thick sequences of limestones with marl and shale intercalations (dammam formation). both formations have a wide aerial extent in the emirates, qatar, and saudi arabia (boukhary & al sharhan, 1998). 2. stratigraphy the stratigraphic section measured along wadi tarabat at the core of the hafit domal structure (fig. 2) is represented by two formations, an older rus formation and younger wadi al nahayan formation. somalina praestefaninii n.sp., a new species of large foraminifera from the dammam formation (lutetian) of gebel hafit, united arab emirates mohamed boukhary1, danielle decrouez2 and yasser a. el safori1 2.1. rus formation, late ypresian the rus formation (thralls & hasson, 1956) is composed of 40 m of white, medium to coarse grained, thickly bedded limestone, with gray chert nodules in the lower part and marl intercalations in the upper part. two members are distinguished within the rus formation, the sulaimi and doha members. 2.1.1. sulaimi member the sulaimi member (boukhary & al sharhan, 1998) is exposed in the lower part of gebel hafit and is composed of about 25 m of thick-bedded white or cream-weathering medium to coarse-grained limestone. the upper part is composed of thinly-bedded cream to light-brown argillaceous limestone. the base of this unit is not exposed. based on foraminifera aca­ rinina bullbrooki bolli, globigerina turgida finlay, and morozovella aragonensis (nuttall), the unit is assigned to the level of the late early eocene. the middle part is either barren or with poorly preserved foraminifera, such as acarinina bullbrooki bolli, a. pentacamerata subbotina, globigerina turgida finlay, morozovella aragonensis (nuttall), and is characterized by a nummulitic horizon with nummu­ lites subramondi de la harpe, besides orbitolites, alveolina and algal nummulitic limestones. this unit is correlated with the middle part of the hili member of the rus formation according to hamdan & bahr (1992). the upper part is conformable with the overlying doha member. 2.1.2. doha member the doha member (boukhary & al sharhan, 1998) is defined from the lower eocene outcrops of qatar. it is unconformably overlain by the dammam formation (as defined from qatar). the unit is composed of well-bedded grey to cream, fine–mediumgrained nodular limestones with chert nodules and marl intercalations (15 m). marls are rich in planktonic foraminifera, including subbotina inaequispira (subbotina), globigerina turgida finlay, moro­ zovella aragonensis (nuttall), m. lensiformis subbotina, m. quetra bolli, acarinina broedermanni cushman & bermudez, a. bullbrooki bolli, a. pentacamerata subbotina, a. pseudotopilensis (subbotina), a. triplex subbotina, a. solda­ geologia croatica 59/2 99–107 4 figs. 1 pl. zagreb 2006 key words: somalina, taxonomy, eocene, united arab emirates. 1 ain shams university, faculty of science, geology department, abbassia 11566, cairo, egypt; e-mail: moboukhary@yahoo.com 2 muséum d’histoire naturelle de genève, 1, route de malagnou, ch-1208 genève, suisse abstract the nodular limestones exposed at the basal part of the gebel hafit (united arab emirates) represent a truncation surface, between the rus and the middle eocene dammam formation (mibazara mem­ ber). somalina praestefaninii n.sp. is a new large foraminiferal species separated from the mibazara member. it is believed that soma­ lina praestefaninii n.sp. is the ancestral form of somalina stefaninii silvestri as it is smaller and has a more simple protoconch. here, it is believed that the taxon somalina (lutetian) could possibly be derived from opertorbitolites nuttall, 1925 (the taxon characteristic for the ypresian). 100 geologia croatica 59/2 doensis subbotina, a. spinuloinflata bandy, and pseudohastigerina micra (cole). some horizons are rich in large foraminifera, e.g. nummulites bassiounii boukhary & blondeau. according to the foraminiferal associations this unit is dated as late early eocene (boukhary & blondeau, 1991). the unit is correlated with the upper part of the hili member of hamdan & bahr (1992). 2.2. wadi al nahayan formation, early/middle lutetian the wadi al nahayan formation (hamdan & bahr, 1992) forms the basal part of the el dammam group. it is composed of tan to light brown limestone with shale interbeds. the dammam group (720 m thick) is separated into four formations from base to top: wadi al nahayan, ain al faydah, maziad, and senaiya formations. the wadi al nahayan formation is separated from the underlying rus formation by a 6 m thick conglomeratic layer, the mibazara member (boukhary et al., 2006). this unit is composed of highly compacted and unoriented limestones pebbles and cobbles. the clasts are highly cemented by a fine reddish matrix of marly nummulitic carbonates rich in large benthic foraminifera, including assilina spira abrardi schaub, somalina praestefaninii n.sp., and nummulites perplexus schaub, similar to the basal u. eocene maziad fm. (m. eocene) fig. 1 location map of the gebel hafit area (after cherif & el deeb, 1984). 101boukhary, decrouez & el safori: somalina praestefaninii n.sp. ... lutetian assemblage of italy (schaub, 1981, p. 132). the unit is exposed on both limbs of the hafit anticline with a variable thickness (3–6 m). these conglomerates represent a sudden shallow shift in sedimentation related to an uplift of the arabia platform during the early to middle lutetian. also, this uplift seems to be responsible for the absence of the p10–p12 interval on the western side of qatar (lutetian lacuna, boukhary & al sharhan, 1998). 2.3. stratigraphic remarks the studied section is correlated with other countries (qatar, saudi arabia and egypt) to delineate important stratigraphic levels related to somalina occurrences (fig. 3). consequently, somalina praestefaninii n. sp. recorded from the basal part of the dammam fomation (lutetian) is the ancestral form of somalina stefaninii silvestri, a characteristic species for the bartonian. also, the sequence of somalina praestefaninii n. sp. could be correlated with the stratigraphic lacuna (between the rus and dammam formations) in qatar, bahrain, kuwait, saudi arabia and egypt (boukhary & al sharhan, 1998; boukhary et al., 2006). accordingly, the mibazara member corresponds to the black and red tuffs with nummulites perplexus of malo, italy (schaub, 1981), where both of the two units are characterized by conglomeratic facies. fig. 2 stratigraphy of the early–middle eocene outcrop section in the hafit area. 102 geologia croatica 59/2 also, somalina hottingeri white may be related to somalina praestefaninii n.sp. according to the known global sequences, four major (2nd order) stratigraphic sequences are recorded as follows. 1 – umm er radhuma–rus sequence (ypresian, ta–2): umm er radhuma–rus/esna thebes–minia formations. this sequence is represented by a succession of shales and limestones and laid down under a major tethyan transgression. the sequence ended with a major regression resulting in the absence of early lutetian deposits in many parts of the arabian plate (boukhary & al sharhan, 1998). 2 – wadi al nahayan–ain al faida sequence (lute­ tian, early–middle ta3): wadi al nahayan–ain al faida / samalut–maghagha–qarara formations. this sequence is represented by a succession of marls and limestones and was laid down under a major tethyan regression accompanied by the middle eocene hyperthermal event (schmidt & shindell, 2003). this sequence is only recorded from the united arab emirates and egypt. a tectonic trigger for this sequence is obvious from the lower egyptian basins (mokattam). lithostratigraphysequence stratigraphy egypt somalina sp. evolution saudi arabiaqatar mokattamnile valley united arab emirates 3rd or de r 2nd or de r c hr on os tra tig ra ph y 4.3 4.2 pr ia bo ni an um bab mb. maadi fm. sc ha ib on fm . se na yi a fm . 4.1 ta 4 dukhan mb. giushi mb.3.6 so m al in a ste fa ni ni i d am m am fm . midra mb./ saila mb. d am m am fm . upper building stone mb. m ok at ta m fm . el fa sh n fm . m az ia d fm . b ar to ni an 3.5 g iz eh en si s m b. (c ita de l) q ar ar a fm . a in a lf ay da h fm . 3.4 m ag ha gh a fm . 3.3 3.2 so m al in a pr ae ste fa ni ni i sa m al ut fm . m ib az ar a m b. w ad ia ln ah ay an fm . ta 3 lu te tia n minia fm. 3.1 doha mb. doha mb.2.9 so m al in a ho tti ng er i sulaimi mb. sulaimi mb.2.8 r us fm . abu samra mb. r us fm . abu samra mb. r us fm . 2.7 thebes fm. 2.6 umm radhuma fm. umm radhuma fm.esna shale umm radhuma fm. d am m am g ro up ta 2 y pr es ia n eo ce ne 2.5 um bab mb. dukhan mb. midra mb./ saila mb. fig. 3 a proposed stratigraphic classification and correlation of the eocene sequences in the united arab emirates, and the somalina evolution trend. grey areas are unconformities. 103boukhary, decrouez & el safori: somalina praestefaninii n.sp. ... 3 – maziad sequence (bartonian, late ta3): maziad / mokattam–fashn / dammam formations. this sequence is represented by limestones deposited under a major transgression of tethys. the sea level rise may have led to the evolution of somalina stefaninii silvestri across broad extents of the arabian and african plates. the sequence has a wide distribution in the various arabian countries. 4 – senaiya sequence (early priabonian, ta4): senaiya / schaibon formations. this sequence is represented by a succession of marl and limestone and was laid down under a major regression of tethys which led to the absence of early priabonian sediments in many parts of the arabian plate. like the wadi al nahian–ain al faida sequence, this sequence is only recorded from the united arab emirates and egypt. 3. systematic palaeontology classification: following loeblich & tappan (1988) suborder: miliolina delage & herouard, 1896 superfamily: soritacea ehrenberg, 1839 family: soritidae ehrenberg, 1839 genus: somalina silvestri, 1939 the genus somalina, considered as monospecific, was first figured by silvestri (1938) and described by himself in 1939 from the lower eocene of somalia and egypt. in 1948, he mentioned and illustrated for the second time, new specimens provided from egypt (gebel ataka, collection of j. cuvillier) of lower eocene age. henson (1948) erected from the lutetian of iraq and oman the species s. danieli henson (s. danieli sp.nov., p. 60, pl. 3, figs. 2–3, henson, 1950). henson’s illustrated thin sections are oblique sections and the only difference, given by this author, from the type species is by that it has a “smooth” or only slightly pitted surface. henson (1950) also mentioned from the upper eocene of iraq somalina danieli sp. nov. var.? (p. 61, pl. 3. figs. 4–6). the difference from the type species is “... a marked inflation of the test at the poles and an exceptionally large, irregular, multicellular, megalospheric embryo ranging in diameter from 0.3 mm to over 2 mm”. henson justified this separation mainly on the younger age of this form, because he admitted that the criteria for its separation are not particularly significant. azzaroli (1952) described and again illustrated s. stefaninii silvestri from the ledian of somalia (in the lower part of the carcar iv) with linderina buranen­ sis nuttall & brighton, pentellina sp., rotalids and miliolids. rahaghi (1978) described somalina stefaninii silvestri from the middle eocene of iran (region of shiraz), the diameter of these specimens is 8 mm and their thickness is 1.6 mm. the embryonic apparatus has an internal dimension (in vertical section) of 600x400 μm. this species is associated with pseudo­ lituolinella reicheli marie, lituonella sp., dictyoconus sp., praerhapydionina sp., and orbitolites complanatus lamarck. also, this author described two new species: somalina gigantea rahaghi and s. khorassani­ ca rahaghi, both from the middle eocene. s. gigan­ tea rahaghi 1978 (pl. 3, figs. 1–3; pl. 4, figs. 1–3; pl. 41) has a diameter of 3.7 mm and a thickness of 0.4 mm for the forma a with a plurilocular apparatus in vertical section, with internal dimension of 1200x500 μm. for the forma b, the diameter is 33 mm for a thickness of 3 mm. the lateral layers, with vacuoles of variable dimensions, are similar to those of the type species. the new species mainly differs from the other species by its shape and size. it is associated with alveolina aff. muni­ eri hottinger and alveolina sp. only the form a of s. khorassanica rahaghi is known (rahaghi, 1978, p. 41–42, pl. 2, fig. 4). the main characteristic of this form is the reduction and even the absence of the lateral layers. its diameter is 0.7 mm and can reach 8 mm. the embryonic apparatus has an internal dimension of 300x400 μm. it is associated with alveolina sp. and rotalia sp. these characteristics, in our opinion, are not sufficient to nominate a new species. however, it is impossible to have a definite opinion on this matter before examining the samples. it should be, nevertheless, noticed that rahaghi must have had an extremely rich collection, which explains the great diversity he was able to observe. he again mentions these species in his later work (rahaghi, 1980). beun (1982) mentioned s. stefaninii silvestri from the lower eocene of se afghanistan, accompanied by assilina spinosa davies, and a. placentula deshayes. kaever (1970) recorded somalina stefaninii silvestri from the middle eocene of afghanistan. kureshi (1969, 1972) mentioned s. stefaninii silvestri from the lower eocene of western pakistan. forteleoni & radrizzani (1972) recorded s. stefaninii silvestri from the middle eocene of somalia (pl. v, fig. 1) with lockhartia haimei (davis), rotalia sp., dendriti­ na sp. and miliolidae. sampo (1969) mentioned soma­ lina stefaninii silvestri (pl. 39 – middle eocene and pl. 45 – ”jahrum formation”) from iran. james & wynd (1965) illustrated somalina sp. from the “jahrum formation” of iran (fig. 66). lehmann (1961) renewed the description of the species after examining specimens from egypt and iran. however, the author noticed that the forms from iran are larger than those from egypt. stratigraphically, lehmann considered somalina as a foraminifera of the lutetian (p. 660– 663, figs. 47–49, tab. 14, figs. 4 & 5). white (1997) described somalina hottingeri white with partially vacuolate lateral walls from wadi fatah, oman, arabian gulf. shamah & helal (1994) recorded somalina stefaninii silvestri from an eocene hill south west gebel el goza el hamra, shabrawet area, cairo–suez district, egypt. 104 geologia croatica 59/2 depository: all types are deposited in the collection of mohamed boukhary, department of geology, faculty of science, ain shams university, cairo, egypt. somalina praestefaninii n.sp. (pl. 1, figs. 1–13) etymology: prior to somalina stefaninii silvestri in age. holotype: pl. 1, fig. 13, sample no. sh. 17b. paratypes: 7 microspheric individuals and 2 megalospheric individuals in thin sections. locus typicus: gebel hafit, wadi tarabat (lat. 24°02’n and long. 55°54’e). stratum typicum: conglomeratic limestone with boulders and fragments containing n. bassiounii boukhary & blondeau and reddish matrix with assilina spira abrardi schaub, early lutetian (wadi al nahayan formation, mibazara member, gebel hafit), sample no. sh. 17b. diagnosis: somalina praestefaninii n. sp. is believed to be the ancestral form of somalina stefaninii silvestri. it differs from somalina stefaninii silvestri by being smaller in size, with a smaller protoconch, and a less complicated embryonic chamber. instead of having a wrinkled protoconch as in the case of somalina stefaninii silvestri, the protoconch of somalina praestefaninii n. sp. is partially divided by a simple loop (fig. 4). description microspheric form: test of medium size, flat to lenticular, sometimes compressed to extremely pointed at the peripheral margin, diameter 15–20 mm, thickness 2– 4 mm, the test consists of median and lateral structures, chambers in the median part of cavities and the lateral chambers are arcuate, larger near the central area and smaller in the outer margin. cavities of the median part are elongated. stolon is represented by a fine passage connecting the chamberlets. aperture not possibly seen since all the material is embedded in hard limestones. megalospheric form: test relatively small, diameter 3–3.5 mm with an average thickness of 500 to 750 μm. protoconch rounded, rectangular to subrectangular, 250–500 μm. the protoconch appears to be occupied by a half circle ribbon, more simplified than that in soma­ lina stefaninii silvestri, in which the protoconch is plurilocular. acknowledgements the authors wish to thank prof. dr. mohamed bassiouni, ain shams university, and prof. dr. bahay issawi, former director of the egyptian geological survey for reviewing the manuscript. the authors are deeply grateful to prof. dr. hans-peter luterbacher for his kind help in identifying planktonic foraminifera. also, we are thankful to prof. dr. rajko pavlovec for his critical review of the manuscript. 4. references anan, h.s. (1996): early eocene foraminifera of jabal hafit, united arab emirates.– m.e.r.c. ain shams univ. earth sci. ser., 10, 147–162. anan, s.h., bahr, s.a., bassiouni, m.a., boukhary, m.a.& hamdan, a.a. (1992): contribution to early eocene–oligocene biostratigraphy of jabal hafit succession, united arab emirates.– m.e.r.c. ain shams univ. earth sci. ser., 6, 225–247. azzaroli, a. (1952): i macroforaminifera della serie del carcar in somalia (eocene medio e superiore) e la loro distribuzione.– palaontographia italica, 47, 99–131. beun, n. (1982): grands ensembles sédimentaires et structuraux des montagnes situées ă l’est de la faille de chaman–arghandeh, entre ghazni et nopur (afghanisstan du sud–est).– bull. soc. géol. france, 7(24)/2, 331–339. boukhary, m. & al sharhan, a.s. (1998): a stratigraphic lacuna within the eocene of qatar: an example of the fig. 4 protoconch characteristics of somalina stefaninii silvestri and somalina praestefaninii n.sp. 105boukhary, decrouez & el safori: somalina praestefaninii n.sp. ... interior platform of the arabian peninsula.– revue paléobiol., genève, 17/1, 49–68. boukhary, m. & blondeau, a. (1991): nummulites bassiounii n. sp. (n. perplexus lineage) of late cuisian from beni hassan, nile valley, egypt.– n. jh. geol. paläont. mh., 21–30. boukhary, m., el safori, y.a., decrouez, d. & faris, m.m. (2006): bioand isotope stratigraphy of the lower/middle eocene section at gebel hafit area, united arab emirates.– n. jh. geol. palaont. mh., 3, 129–147. cherif, o.h. & el deeb, w.m.z. (1984): the middle eocene–oligocene of the northern hafit area, south of al ain city (united arab emirates).– géologie méditerranéene, 11/2, 207–217. forteleoni, p.g. & radrizzani, g.p. (1972): microfaunes form the karka formation (somaliland).– rev. esp. micropal. serie 7, 3, 1975, proc. 5th african colloq. micropal., addis abeba, 10–12 avril 1972, 385–415. hamdan, a.r.a. & bahr, s. (1992): lithostratigraphy of the paleogene succession of northern jabal hafit, al ain area, united arab emirates.– m.e.r.c. ain shams univ. earth sci. ser., 6, 201–224. henson, f.r.s. (1948): larger imperforate foraminifera from south western asia.– british museum nat. hist., 16, 127 p. henson, f.r.s. (1950): middle eastern tertiary peneroplidae (foraminifera), with remarks on the phylogeny and taxonomy of the family.– unpubl. phd thesis, leiden (wakefield), 70 p. hunting (1979): report on mineral survey of the united arab emirates, geology and mineral potential.– hunting geology and geophysics ltd. sponsored by petroleum & mineral resources, abu dhabi, 9, 1–29. james, g. & wynd, j.g. (1965): stratigraphic nomenclature of iranian oil consortium agreement area.– aapg bull., 49/12, 2182–2245. kaever, m. (1970): die alttertiären grossforaminiferen südost-afghanistans unter besonderer berücksichtigung der nummulitiden. morphologie, taxonomie und biostratigraphie.– munster. forsch. geol. paleont., h. 16, 400 p. kureshi, a.a. (1969): eocene biostratigraphy of pakistan.– mem. b.r.g.m., coll. sur l’eocène, paris, mai 1969, 69, 219–224. kureshi, a.a. (1972): the cretaceous and tertiary larger foraminifera of west pakistan.– rev. esp. micropal., 73, proc. of the 5th african colloq. on micropaleontology, 553–564. lehmann, r. (1961): strukturanalyse einiger gattungen der subfamilie orbitolitinae.– eclogae geol. helv., 54, 597–667. loeblich, a.r. & tappan, h. (1988): foraminiferal genera and their classification.– nostrand reinhold company, new york, 970 p. rahaghi, a. (1978): paleogene biostratigraphy of some parts of iran.– nat. iranian oil company, geol. lab. pub., 7, 165 p. rahaghi, a. (1980): tertiary faunal assemblage of qum– kashan, sabzewar and jahrum areas.– national iranian oil company, geological laboratories, publication 8, 1–64. sampo, m. (1969): microfacies and microfossils of the zagros area, southwestern iran (from pre-permian to miocene).– sed. petr. series, 12, brill., leiden, 102 p. schaub, h. (1981): nummulites et assilines de la téthys paléogène. taxinomie, phylogénèse et biostratigraphie.– mém. suisse paléont., 104, 236 p. schmidt, g.a. & shindell, d.t. (2003): atmospheric composition, radiative forcing, and climate change as a consequence of a massive methane release from gas hydrates.– paleoceanography, 18, 1004, 4-1–4-9. shamah, k. & helal, s. (1994): large foraminifera from the eocene sediments of shabrawet area, cairo–suez district, egypt.– rev. paléobiol., 14/1, 21–33. silvestri, a. (1938): foraminiferi dell’eocene della somalia, parte i in paleontologia della somalia. iv fossili dell’eocene.– palaeontolographia italica, xxxii, suppl. 3, 49–89 (37–77). silvestri, a. (1939): foraminiferi dell’eocene della somalia, parte ii in paleontologia della somalia. iv fossili dell’eocene.– palaeontolographia italica, xxxii, suppl. 4, 1–102 (79–180). thralls, w.h. & hasson, r.c. (1956): geology and oil resources of eastern saudi arabia.– 20th international geol. cong. mexico, symposium, store yacimientos de petroleo y gas, 11, 9–32. white, m.r. (1997): a new species of somalina (somalina hottingeri) with partially vacuolated lateral walls from middle eocene of oman.– jour. of micropalaeont., 16, 131–135. manuscript received february 28, 2006. revised manuscript accepted november 24, 2006. 106 geologia croatica 59/2 plate 1 somalina praestefaninii n.sp., sample sh17b, mibazara member, wadi al nahayan formation, gebel hafit figs. 1–10 microspheric form of somalina praestefaninii n.sp. (fig. 6 in boukhary et al., 2006). scale = 1 mm. figs. 11–13 megalospheric form of somalina praestefaninii n.sp. scale = 1 mm. 107boukhary, decrouez & el safori plate 1 108 geologia croatica 59/2 interdependence of petrophysical properties and depth: some implications of multivariate solution on distinction between the lower pontian hydrocarbon-bearing sandstone units in the western part of the sava depression bruno safti∆1, zoran peh2, josipa veli∆1 and ivanka jüttner1 geologia croatica 54/2 259 277 11 figs. 9 tabs. zagreb 2001 key words: sandstone reservoir rocks, reservoir properties, multivariate analysis, genetic stratigraphic sequences, lower pontian, oil and gas fields, sava depression, pannonian basin, croatia. kljuëne rijeëi: pjeπëenjaëke kolektorske stijene, kolektorska svojstva, viπestruka statistiëka analiza, genetske stratigrafske sekvencije, donji pont, naftna i plinska polja, savska depresija, panonski bazen, hrvatska. 1 faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, hr-10000 zagreb, croatia; e-mail: bsaft@rgn.hr 2 institute of geology, sachsova 2, hr-10000 zagreb, croatia. abstract statistical analysis of reservoir data from the lower pontian clastics (the most important hydrocarbon reservoir rocks in the sava depression), supports established knowledge of the interdependence of petrophysical properties and depth. irrespective of the focus that the reservoir data may be studied and presented, depth always emerges as a fundamental reservoir descriptor. this is particularly evident when studying the differences between widely spaced oil and gas fields, when the numerical model completely separates the two sets of descriptor variables, indicating two different sources of their internal variability. porosity and permeability belong to “intrinsic rock properties” while depth must be ascribed to other sources, e.g. tectonic subsidence. discriminant function weighted with depth (df1) has such group centroid values, that zones can be drawn within a particular field that coincide with structural relationships. on the function marked with reservoir properties (df2), group centroid values are higher close to the axes of palaeotransport channels, where sandstone layers are the thickest and particles are best sorted. group centroid values on the third function (df3) depict the areas of relatively higher permeability in the apical parts of structures, possibly caused by fracturing due to folding, or by cementation of other parts of reservoirs, where the circulation of pore waters was more pronounced. in the case of the most thoroughly investigated æutica field, the inverse relationship between depth and porosity becomes evident when compared with the direction of palaeotransport and thickness of reservoir rocks on the respective structure and thickness maps. saæetak numeriëki modeli izraëunati na osnovi podataka o kolektorskim svojstvima donjopontskih klastiënih stijena kao vaænih stijena nosioca ugljikovodika u podruëju savske depresije u skladu su s ëinjenicama o meusobnoj ovisnosti fiziëkih svojstava i dubine. neovisno o pristupu analizi varijacija kolektorskih svojstava, dubina se uvijek istiëe kao najvaænija varijabla koja opisuje leæiπte. to osobito vrijedi pri prouëavanju razlika izmeu meusobno udaljenih leæiπta nafte i plina. u tom sluëaju numeriëki model u potpunosti razdvaja dva skupa pokazatelja, ukazujuêi na dva razliëita izvora njihove unutarnje varijabilnosti. porozost i propusnost pripadaju podruëju inherentnih svojstava samih stijena, dok dubinu treba pripisati drugim uzroënicima, poglavito subsidenciji. centroidi grupa na funkciji obiljeæenoj dubinom (df1) imaju takve vrijednosti da se unutar jednoga polja moæe ocrtati zone koje su u skladu sa strukturnim odnosima. poviπene vrijednosti centroida na funkciji obiljeæenoj kolektorskim svojstvima (df2) nalaze se uz osi paleotransportnih kanala gdje su pjeπëenjaci najdeblji, a zrnca najsortiranija. vrijednosti centroida grupa na treêoj diskriminantnoj funkciji (df3) ukazuju da je propusnost najveêa u tjemenima struktura uzrok ëemu mogu biti pukotine nastale uslijed boranja, te cementacija u ostalim dijelovima leæiπta s izraæenijom cirkulacijom slojne vode. u sluëaju najpotpunije istraæenog polja æutica, obrnuto proporcionalan odnos izmeu dubine i poroznosti posebno je naglaπen kad se matematiëki model usporedi sa smjerom paleotransporta i promjenama debljine kolektorske stijene na odgovarajuêim strukturnim kartama. 260 geologia croatica 54/2 1. introduction and previous investigations analyses of well cores are surely among the most important procedures during exploration for hydrocarbon accumulations and also during the subsequent production phase. data obtained by laboratory measurements are the most straightforward measure of reservoir rock properties, i.e. of the porous medium. the first parameter is the “storage capacity” or porosity, and the second one is the “circulation capacity” or permeability. in their systematisation of laboratory measurements during the various phases of development and production, gori»nik et al. (1985) have put the determination of porosity and permeability in first place within the phase of reservoir development. in this phase, together with other analyses, it enables the quantitative description of a reservoir, calculation of reserves and its techno-economical evaluation. the most realistic values of relative permeability are vital for such calculations (krizmani∆ et al., 1976), and this can be achieved by a very carefully chosen set of core samples. samples have to be representative and of homogeneous composition and structure, because the permeability varies with the lamination of sandstones. furthermore, the rigorous x-ray examination of homogeneity is required. it was also observed that, if a core is only weakly layered perpendicular to the flow direction, it doesn’t necessarily affect the relative permeability. conversely, if a core is layered parallel to the direction of flow, it has a large effect on permeability. it was also proven by krizmani∆ (1980) that significant differences in measured permeability can occur between laboratories and even within a single laboratory, if there was a change of instrument, measurement media or laboratory conditions. as for the further processing of measured data, numerous reservoir management investigations have shown that the architecture and properties of the hydrocarbon-saturated layers may show great spatial variability that often renders the available data unfit for obvious geological interpretation. much uncertainty is thus introduced from the start in the prediction of reservoir performance on a regional or even local scale. however, the abundance of data, including core and well log data, can provide a more or less integrated picture of the reservoir attributes if multivariate geostatistical techniques are used. such techniques are indispensable, not only because reservoir data are essentially of a multivariate nature, but also because this method allows their reduction into an integrated model. reservoir performance is a result of the interdependency of its various characteristics. method which differentiates between reservoirs or units pertaining to various fields, usefully emphasises the differences between depth, rock properties, or some other available reservoir data. of these, discriminant analysis is a very advantageous multivariate method because one can directly ponder on differences between the groups and simultaneously infer the predictor variables that are the most responsible for these differences in the study area. in this study, porosity and permeability were statistically analysed, because these are the two properties that have the most influence, both on oil and gas recovery and on the methods utilised to increase this recovery. there is a certain proportion of hydrocarbons that are going to remain in the known reservoirs, both on a macro and micro scale. the percentage of the oil remaining in place is mostly dependent on the complexity of a reservoir and on its lithology, especially the distribution of flow barriers. it is with new procedures of reservoir management that the quantities of remaining oil in certain pools are reduced. advances in technology, such as 3d-seismics or horizontal wells, enable discoveries in places where hydrocarbons still remain, where they were by-passed in initial saturation, or in reservoirs that would have been regarded as depleted according to the usual standards (bassiouni & veli∆, 1996). 1.1. improvements to the recovery ratio croatian literature that directly or indirectly discusses the relationship between porosity and permeability comprises papers that are concerned with methods to improve oil recovery, or these that are based on statistical methods of analysis. it has already been stated that large amounts of hydrocarbons remain in reservoirs at the end of the primary depletion period. in fact, this is usually more than 60% of the original oil in place (ooip). according to production data published by se»en (1979), the average oil recovery in croatia, achieved in the primary production stage for solution gas drive was in the range of 16-20%, and for the gas cap drive it was between 2025%, while the water-drive resulted in recovery of 3050%. the average oil recovery in 1970 was 25%, while the most unfavourable 16% occurred in the largest reservoirs of the ivaniê-grad and æutica fields. an average recovery of 35% was achieved post 1975 (se»en, 1979, 1980, 1987; bauk et al., 1988). there was a sustainable growth in oil production in croatia until 1980, the year when it crossed the 3 mil.t/yr., after which it remained more or less stable throughout the following decade. subsequently, the production started to decline because of lost reservoir energy and there were no new compensating discoveries (peri∆, 1992). production histories from around the world reveal that waterflooding is the most adequate and economic method for improving oil recovery. it was actually discovered by chance back in the 1870’s in pennsylvania. in croatia, the method of conventional waterflooding was first implemented in 1972, in one layer of the ivaniê-grad oil field. due to the fact that this is usually applied after the primary production stage, waterflooding is regarded as a secondary phase of depletion i.e. as a secondary method of production, together with a method of gas injection in primary gas caps. this second method (gas injection) has been applied in croatia since 1982, when it was initialised in some layers (a1 3) of the æutica oil field (peri∆, 1992). from reservoirs with water injection, oil recovery in the range of 4054% was achieved, primarily due to a favourable oil viscosity of 0.64-1.31 mpa s (se»en, 1980). nine reservoirs in total were injected with water, and these were the reservoirs that contained 58% of the ooip in croatia (se»en et al., 1988; bauk et al., 1988). gas was injected into two reservoirs with primary gas caps. between 1982-1987, these methods resulted in the production of an additional 16 mil. t of oil. in the late 1980’s, the amount of oil produced from the waterinjected pools accounted for 50% of the total annual production. approximately 50 years ago, further new methods of increasing oil recovery were developed and tested. according to their planned implementation in the third phase, they were called “tertiary recovery techniques”. some of the techniques involved were aimed at producing oil remaining in the part of the reservoir already swept by displacing fluid (called increasing displacement efficiency). conversely, increasing sweep efficiency relates to techniques used to extract the oil remaining in the part of the reservoir not swept by displacing fluid. some techniques, of course, can increase both displacement and sweep efficiency. the use of such techniques is called “enhanced oil recovery” (eor). technically, eor consists of methods aimed at increasing the ultimate oil recovery by injecting appropriate agents not normally present in the reservoir, chemicals, solvents, oxidizers and heat carriers, in order to induce new mechanisms for displacing oil. these methods are based on the fact that a low oil recovery by conventional methods results from the combined action of several physico-chemical factors (gori»nik, 1981; se»en, 1979, 1980, 1987; bauk et al., 1988). these factors are: the interfacial tension between the oil and injected fluids, varying viscosity of oil, water and especially of gas (resulting in injection fluids rapidly bypassing the viscous oil), capillary attraction between rocks and fluids, as well as heterogeneity in the petrophysical properties of reservoir rocks in both a vertical and horizontal direction. displacement of the remaining oil from reservoirs can be achieved by the reduction of interfacial tension between oil and water and by reduction of capillary forces. these processes can be divided into three groups according to the procedures applied thermal, chemical and gas injection in miscible, near-miscible or nonmiscible conditions (se»en, 1980; bauk et al., 1988). a preliminary decision in the selection and use of tertiary methods (gori»nik, 1981) is dependent on technological and economic factors (particularly the price). among others, technological factors such as lithology, depth and thickness of reservoir rocks, pressure and temperature, gravity and viscosity of oil, and also the (average) permeability of the reservoir are the screening criteria for selection of the main eor processes. se»en et al. (1988) emphasised that in order to obtain good connections between the injection and production wells, it is of primary importance to thoroughly study the reservoir continuity and distribution of the porosity, permeability and saturations within a reservoir. from the thermodynamic point of view, research was undertaken on the injection of dry gas in the æutica oil field in order to achieve miscibility conditions between injected dry gas and oil in place (jüttner, 1996). according to peri∆ (1992) up to 80% of the known geological reserves in production, and around 75% of the total “balance reserves” (the fraction that can be economically produced with existing technology see bauk, 1996) of oil in the croatian part of pannonian basin occur in sandstone reservoirs. therefore, the study of porosity and permeability of these sandstones is of primary importance in the selection of methods for enhanced oil recovery. results of various studies (gori»nik et al., 1978, 1980, 1993; bauk et al., 1988; peri∆ et al., 1991) have indicated that the optimal method would be the displacement of oil by co2-injection in almost totally miscible conditions. the best candidates for this method are the reservoirs of the ivaniê-grad and æutica fields, where between 50-60% of the residual oil could be produced (bauk et al., 1988). recently (jüttner & rajkovi∆, 2001), economic, and especially environmental factors have been emphasised as the most important in the management of reservoirs. 1.2. previous statistical analyses few papers published in croatia document the use and results of mathematical methods in geology, especially in the field of subsurface geology. hernitz & jurak (1973) where pioneering in their statistical proof that, in the region of ivaniê-grad, there is a clear stochastic dependence between the thickness of lithostratigraphic units formations and depth of marker horizons that define them. an average correlation index of 0.8 was calculated. molak (1977) statistically analysed thousands of laboratory measurements of porosity and permeability, altogether 5,921 core sample taken from 11 oil and gas fields. the okoli, struæec and æutica fields were also contained in this data set. in all cases, these were the sandstones with hydrocarbon accumulations. as has been found elsewhere, several conclusions were reached: porosity is characterised by a normal distribution, permeability by log-normal distribution, both these properties reduce with depth and there is a strong (functional) correlation between the porosity and permeability. based on the correlation between the porosi261saftiê, peh, veliê & jüttner: interdependence of petrophysical properties and depth... 262 geologia croatica 54/2 ty and permeability, the permeability can be comparatively reliably determined on the basis of porosity data good correlation was achieved by the square and linear function of porosity in the 14-34% range. it is assumed that certain statistical procedures were also used in papers where values of average permeability were published (se»en, 1979; bauk & keber, 1980; gori»nik, 1981). in a sense, the statistical analyses of jüttner et al. (1999, 2001) are a continuation of the study undertaken by molak (1977). they were governed by the aim of studying interdependence between the porosity and permeability of the lower pontian sandstones in the western part of sava depression, and the stratigraphic architecture of these sediments together with palaeotectonics. the results partly supported the earlier work, except that, when the high-resolution stratigraphy of reservoirs is taken in account, there are significant differences between the fields. for example, there is no correlation between the depth and porosity and depth and permeability in the sandstones of gss poljana at the struæec field. similar correlations for the okoli field were moderately to well expressed. 2. geological setting statistical analysis of the porosity, permeability and depth was undertaken on measurements from the lower pontian clastics. these, together with the pannonian sandstones, are the most important hc reservoir rocks in the sava depression. the typical composition of these sediments is a sequence of grey, fine-grained sandstones and clayey-silty marls that were deposited in a brakish marine environment. sandstone layers in the deeper parts of the depression are intercalated with and embedded within the marls. lithostratigraphically, these sediments form the kloπtar ivaniê formation, encompassing all the strata between the e-log markers z’ (base) and rϕ (top), as explained by ©imon (1970). the formation is subdivided into three smaller units genetic stratigraphic sequences (gss) which in geochronological order are the poljana, graberje and bregi units (fig. 3). each gss represents one depositional pulse starting with a progradational phase, a middle aggraddational section, and ending with retrogradation and a subsequent marine flooding surface followed by the overlying sequence (safti∆, 1998). sandstone bodies in all of the three genetic sequences are elongated in the nw-se direction, and according to their maximal thickness axes demonstrate a translation of the depocentre in a southwest and westerly direction. reservoir properties were measured on horizontal core plugs from the productive intervals of 4 fields in the western part of the sava depression. porosity was measured at a 10-cm spacing and permeability at 1 m. these fields are, from nw-se (figs. 1 and 2), the dugo selo field (wells marked with glwhich stands for “glavniëica”), æutica (wells marked with æu-), okoli (ok-) and struæec (wells marked owhich stands for “osekovo”). the nature of the data that were available limited the possibilities for analysis and interpretation. there were no petrographic data details of the composition and texture of sandstones. it can only be said that they are mostly fine-grained, laminated and interlayered with thin marls and that there is an internal architecture of sandstone bodies in the shape of a submarine fan (safti∆, 1998). another limitation was that there were no pressure data to be analysed. a general constraint is that no overpressure zones were found in these sediments, which is presumed to result from both the numerous sandstone layers and at least three intersecting fault systems that were reactivated in several tectonic phases and enabled the migration of pore water (veli∆, 1980, 1983; prelogovi∆ et al., 1998; lu»i∆ et al., 2001). finally, there was no measure of the primary vs. secondary porosity, which limited the possibilities for interpretation. also, the entire area is under an active wrench tectonic regime in neotectonic phase, characterised by the general orientation of the maximal horizontal stress n-s, with significant local variation in the vicinity of active faults (prelogovi∆ et al., 1998). the generalised structure map of the e-log marker z’ (base of kloπtar ivaniê formation) given in fig. 4, also shows the shaded outlines of the three fields that are comparatively closely spaced æutica, okoli and struæec. the dugo selo field lies 24 kilometres nw of the æutica field. looking at the structure contours of this map, simplified structures can be observed, and also the fact that the reservoirs of these fields lie at various depths. the contours of the æutica and struæec fields coincide with anticlines, while the deepest, okoli field lies on the plunging nose of an anticline. the shallowest samples are from the dugo selo field (882-1,013 m), the deepest from okoli (1,700-2,015 m), those from æutica lie in the range of 1,492-1,842 m, and 1,0471,949 m from struæec. these depth ranges can be seen in the schematic cross-section given in fig. 3. significant differences in the thickness of the kloπtar ivaniê formation can be observed over short distances (fig. 5, veli∆, 1980). the maximum of more than 700 m occurs south of the okoli field. the unit gradually thins in a ne direction, towards the margin of the sava depression. it is also significant that there is a reduction of thickness that coincides with the apical parts of the æutica, okoli and struæec structures. this can be attributed to a palaeostructural influence, i.e. to synsedimentary tectonics that uplifted these structures and partly to differential compaction in the areas where less or no sandstones were deposited on top of the structures. the æutica structure is characterised by tectonic movements of inherited character. in the neogene, the structure of the struæec field was partly renewed and partly inherited, while the okoli field 263saftiê, peh, veliê & jüttner: interdependence of petrophysical properties and depth... fig. 1 situation map. fig. 2 index map showing locations of field areas. 264 geologia croatica 54/2 structure experienced diversification into three smaller anticlines (veli∆, 1979, 1983). the thickness of the oldest of the three genetic stratigraphic sequences within the kloπtar ivaniê formation gss poljana is illustrated in fig. 6, primarily based on well data. thorough wireline log correlation across the western part of the sava depression (safti∆, 1998) confirmed that the areas of maximal thickness of this unit coincide with the maximal thickness of the sandstone reservoirs. these elongated sedimentary bodies were formed by accumulation of sandy material within the submarine channels that formed conduits for the sedimentary transport. this explains why the generally nw-se trending palaeodrainage axes are drawn through the areas of maximal thickness of gss poljana. two main channels can be distinguished in the mapped area the main palaeotransport axis of the sava depression, and a main local transport channel that is located to the north. 3. multivariate analysis of the well data exploratory multivariate analysis is a powerful statistical tool when dealing with a volume of numerical data as, for example, various measurements from wells across the oil fields. through the process of data contraction it can reduce problems of structuring, distinguishing or comparison of data to scale providing a clearer insight into the underlying geological control. also, it helps to organise the data into a mappable form which clarifies interrelationships more clearly. discrimination functions can be particularly convenient when applied to a problem involving several thousand of data scattered within and across different boundaries such as wells, geological units or hc fields, and which contain the same set of observed qualities. their primary purpose is to separate the a priori d e f ifig. 3 cross-section dugo selo-æutica-okoli-struæec. 265saftiê, peh, veliê & jüttner: interdependence of petrophysical properties and depth... ned clusters or groups in such a way that inter-group variance is maximised in comparison to the variance within each group (dillon & goldstein, 1984). truly, the process of discrimination transforms the original set of data into a number of discriminant scores that place each object or group (represented by its mean) along one or more lines defined by the computed linear discriminant functions (davis, 1986). simultaneously, the multivariate problem simply collapses to the least-dimensional solution that is dependent on the number of groups or variables, whichever is the smaller. 3.1. the strategy of analysis the data collected from a great number of wells through the kloπtar ivaniê formation can be organised in several ways, as the grouping criteria are subject to different conceptions. the most obvious manner of grouping follows the trends of depth and area after which the two types of clusters can be formed, namely the fields and (stratigraphic) units. such a priori formed groups are quite “natural”, and basic differences between them can be easily inspected provided that the data variability is great enough to disclose them. however, merely three or four or even more (combining fields with units) groups of data, thus formed, do not allow their mutual relationship to be meaningfully represented on relevant field maps since there are insufficient mappable points to produce a grid. also, only the lowest unit the gss poljana contains the entire body of measured data across the investigated area, and in most of the wells. on the other hand, the well data are arranged in intervals rendering their representation, unless depicted in a cross-section, largely abstract. to avoid this problem and, possibly, to focus on a narrower stand such as a single field, the groups can be reshaped by combining the wells with units or fields, or both. thus, each well might be portrayed as a group with its intervals as objects. through this rearrangement, new groups can be created and represented on a map via the relevant well locations. these groups though, being arbitrarily created, can introduce a form of artificiality into the “naturalness” of the original data. in such a case interpretation must be exercised with great care as differences between larger groups, such as fields or units, can easily be offset by variations within the smaller ones, such as wells. three discriminant exploratory analyses can be performed following the observed methods of grouping the fig. 4 structure contour map base of kloπtar ivaniê formation. 266 geologia croatica 54/2 well data. in the first case, the data are arranged in such a way that sources of variation between the hydrocarbon-bearing fields dugo selo (wells labelled gl-), okoli (wells labeled ok-), struæec (wells labeled o-) and æutica (wells labeled æu-) can be examined. the second case deals with differences between the three units containing the sandstone reservoirs the gss poljana, gss graberje and gss bregi units, that always appear in the same superpositional sequence. the third possibility was a well-field combination that is narrowed to the poljana unit and contains 31 groups (wells). this last attempt was aimed at highlighting possible variations within a single unit. in all three cases, the same set of four variables is utilised, namely depth (d), vertical permeability (kv) , horizontal permeability (k h ), and porosity (φ). 4. results 4.1. case 1 “fields” discriminant analysis performed on the data matrix of four groups containing 1,401 valid objects and four variables resulted in three discriminant functions, the first of which explains almost 94% of the total system variability. the results, arranged in table 1, portray the structure matrix of correlation between discriminant functions and observed variables. the first discriminant function (df1) has a strong loading on only one variable, namely the descriptor of depth, while the remaining three variables can be deemed irrelevant. according to its structure it can be properly labelled the depth function. the other two functions can be interpreted as reflecting the relationships among the basic physical properties. of these, the second (df2) is loaded heavily with porosity, while the fig. 5 isopach map of kloπtar ivaniê formation. discr. funct. variable df1 df2 df3 depth -0.86* -0.28 -0.41 horiz. permeability 0.02 0.45 0.74* vert. permeability 0.04 0.42 0.91* porosity 0.06 0.97* 0.25 % explained 93.66 5.91 0.42 table 1 the structure matrix for fields. 267saftiê, peh, veliê & jüttner: interdependence of petrophysical properties and depth... third (df3) deals with indices of permeability. both are slightly bipolar as their predictor variables are negatively associated with depth, although the relation is weak. thus the sequence depth p o r o s i ty permeability in decreasing order of variability and interpretability can be established through the fields. relationships among the descriptor variables and related groups can best be represented diagrammatically, in which case the discriminant functions are viewed as axes in the reduced discriminant space. however, diagrams can not be directly compared as different scales are used in both cases. discriminant axes on the scatterplot of variables (figs. 7a-b) are drawn as normalised vectors, while on the scatterplot of canonical means (centroid values for field groups) these indicate an altogether different scale (figs. 7c-d). thus, the interpretation of interdependence between variables and groups is always based on their shared position along the appropriate axis. the points placed close to the axis intersection (main centroid) are subject to little or no discrimination whatsoever. the interpretation of diagrams is straightforward. comparing the pairs of scatterplots it is easily observed that, according to df1, the fields are arranged in the sequence of okoli æ u t i ca s t r u æ ec dugo selo (glavniëica), of decreasing depth. the æutica field is marked with an almost zero value (table 2) of its centroid (group mean) functioning as the average depth value for fields. regarding df2, the diagram (fig. 7c) is indicating increasing porosity with dugo selo field and decreasing porosity with the struæec and, particularly, the okoli fields. in the case of df3 only the dugo selo field is clearly discriminated (fig. 7d) on account of its lower permeability, while other fields remain virtually indistinguishable. a classification matrix (table 3) helps to understand the accuracy of discrimination results via the rela fig. 6 isopach map of gss poljana with directions of palaeotransport. discr. funct. group df1 df2 df3 dugo selo 9.09 0.41 -1.70 okoli -1.64 -0.84 -0.05 struæec 3.99 -0.50 0.09 æutica -0.09 0.09 0.00 table 2 group centroids for fields. 268 geologia croatica 54/2 tionship between the a priori defined and mathematically computed groups. discrimination efficiency exceeds 92% of a combined sample although it is unevenly distributed among the groups. the okoli field displays the lowest classification results as most of its samples proved to be more akin to the æutica field. the correctly classified groups are placed diagonally across the table. 4.2. case 2 “units” as in case 1, discriminant analysis is carried out on the same data matrix but with only three groups representing the three units through all fields (gss poljana, gss graberje and gss bregi, superimposed as in fig. 3). the analysis resulted in two discriminant functions as can be seen in the structure matrix (table 4). although the depth variable is an obvious predictor due to the fact that the sandstone units are always bedded in the same sequence of increasing depth, gss bregi g s s g r a b e r je -gss poljana, it is nevertheless included into the analysis for the possible interrelations with physical properties of rocks. in contradistinction to the discrimination among fields, the first discriminant function (df1) is of a prominently bipolar nature, weighting the strongly loaded depth variable against the moderately loaded set of physical properties (kh, kv and porosity), as can be seen from table 4. it accounts for almost the total variability (99.9%) of the units system. the second discriminant function (df2) is essentially concerned with a single variable, namely that of porosity, but having almost negligible interpretative worth (0.1%) it can be fig. 7 comparison of variables and fields: scatterplots of variable loadings (a, b) and of group means (c, d). mathematically defined group group d.s. ok. str. æu. total % correct dugo selo 2 0 0 0 2 100.00 okoli 0 8 0 87 95 8.42 struæec 0 0 60 4 64 93.75 æutica 0 1 20 1219 1240 98.31 total 2 9 80 1310 1401 92.01 table 3 classification matrix for fields. 269saftiê, peh, veliê & jüttner: interdependence of petrophysical properties and depth... excluded from further considerations. thus, the interpretation of results in the case of units is very simple, particularly when inspecting the diagrammatic representation of variable-unit association (figs. 8a-b). the gss bregi unit is placed on top of the others as expected, with a slight increase of kh, kv and porosity values, but the graberje unit instead of poljana shows the inverse relationship of their natural sequence (table 5, fig. 8b) which requires further consideration. with regard to df2, the gss bregi and gss poljana are quite indistinctive, while gss graberje is assigned with decreased porosity. the classification matrix (table 6) reveals the apparent misclassification of the graberje unit which is, according to all its properties, most similar to the lowest, poljana unit. the overall classification accuracy exceeds 94% of a combined sample (1,401 valid cases). discriminaton analysis for both fields and units represents a great error in classifying samples from the okoli wells drilled through the gss graberje sandstone layers, the middle of the three units. the canonical mean (group centroid) for gss graberje in table 5 is highlighted, which is excessive, indicating deeper emplacement, when compared to the sandstones of gss poljana. this may be the result of different or changed physical properties that caused the reduction of reservoir quality of the unit in question. 4.3. case 3 “wells” discriminant analysis performed on 31 combined groups (associating the wells from all fields with the lowest unit, gss poljana) with 1,069 valid objects and the same four variables, resulted in four discriminant functions, the first three of which can be meaningfully interpreted. the results are similar to case 1, with one discr. funct. variable df1 df2 depth 0.92* 0.02 horiz. permeability -0.39 0.21 vert. permeability -0.46 -0.10 porosity -0.37 0.70* % explained 99.90 0.10 table 4 structure matrix for units. discr. funct. group df1 df2 gss bregi -2.18 -0.00 gss graberje 2.19 -0.70 gss poljana -0.64 0.00 table 5 group centroids for units. fig. 8 comparison of variables and units: scatterplots of variable loadings (a) and of unit means (b). mathematically defined group group bregi graberje poljana total % correct gss bregi 295 0 26 321 91.90 gss graberje 0 0 4 4 0.00 gss poljana 53 0 1023 1076 95.07 total 348 0 1053 1401 94.08 table 6 classification matrix for units. 270 geologia croatica 54/2 exception that much greater importance is placed on the first discriminant function (over 98%) which is weighted with the single variable of depth. explaining almost the entire variability potential of the wells system, df1 acquires the quality of a fundamental discriminator indeed within the area of investigation (table 7). far behind lie the two remaining functions (explaining together less than 2% of the system’s variance) which, nevertheless, are still capable of elucidating some nuances that may appear across relatively short distances, that is, within the same field. the first discriminant function strongly separates the a priori established groups on the basis of their relative depth, as can be seen from close inspection of the group and variable scatterplots (figs. 9a-d). the arrays of group centroids are strewn diagonally across the diagrams, emphasising the distinct position of the dugo selo and struæec fields (gland owells). obviously, the pertinent fields are placed less deeply in respect to the remaining field-unit assemblage. alternatively, the points representing the æutica wells are concentrated around the main centroid (axis intersection) indicating intermediary depths at regional scale, while the okoli points are placed somewhat deeper. moreover, one can discr. funct. variable df1 df2 df3 depth -0.99* 0.09 -0.06 horiz. permeability 0.03 0.70 0.70* vert. permeability 0.02 0.60 0.56* porosity 0.04 0.96* -0.24 % explained 98.26 1.11 0.54 table 7 structure matrix for wells. discr. funct. group df1 df2 df3 gl-16 57.86 -1.65 -1.95 ok-1 -10.40 -0.83 0.33 ok-4 -5.91 0.26 0.61 ok-20 -7.67 -0.39 1.46 ok-35 -8.98 -0.63 0.31 o-127 25.22 -2.00 0.58 o-135 25.83 -0.33 -0.71 æu-25 5.94 0.61 -0.52 æu-26 -1.37 0.01 -0.17 æu-30 6.55 0.91 0.43 æu-42 0.91 1.99 0.96 æu-45 -0.30 -0.21 0.33 æu-54 -3.13 -0.03 -0.32 æu-62 -0.14 -1.56 0.51 æu-66 1.34 -1.32 0.86 æu-81 3.25 0.34 0.77 æu-86 1.04 1.10 0.38 æu-94 0.51 0.68 0.58 æu-122 -0.57 -0.89 0.09 æu-124 1.40 0.06 -0.57 æu-130 0.31 0.18 -0.44 æu-146 4.11 1.37 1.11 æu-155 -1.79 0.09 -0.46 æu-156 -0.56 -0.47 -0.63 æu-157 -0.95 0.03 -0.81 æu-158 -0.76 0.95 -0.50 æu-159 -0.59 0.39 -0.23 æu-161 -0.54 -0.16 -0.59 æu-163 -0.26 0.94 -0.73 æu-164 0.34 0.13 -0.51 æu-167 -0.53 -0.24 -0.05 table 8 group centroids for wells. group no. of cases % correct gl-16 2 100.00 ok-1 5 0.00 ok-4 3 0.00 ok-20 15 46.67 ok-35 64 100.00 o-127 16 93.75 o-135 26 80.77 æu-25 6 0.00 æu-26 132 46.97 æu-30 91 98.90 æu-42 7 42.86 æu-45 16 0.00 æu-54 326 82.21 æu-62 58 68.97 æu-66 30 53.33 æu-81 3 0.00 æu-86 34 41.18 æu-94 35 17.14 æu-122 5 0.00 æu-124 10 20.00 æu-130 12 0.00 æu-146 32 50.00 æu-155 28 0.00 æu-156 12 0.00 æu-157 16 0.00 æu-158 22 9.09 æu-159 13 0.00 æu-161 5 0.00 æu-163 7 0.00 æu-164 27 22.22 æu-167 12 0.00 total 59.31 table 9 efficacy of classification for wells. 271saftiê, peh, veliê & jüttner: interdependence of petrophysical properties and depth... observe that æupoints are not dispersed widely along the axis, which is a positive indicator of their rather constant depth at their respective level. the second and third discriminant functions separate the groups with much less efficacy than the first one, because porosity and permeability are much poorer predictor variables than depth. such a situation implies that within-group variance may strongly offset the difference among groups, which is why great caution must be exercised in explaining the group separation along these two axes. their low discriminating capacity may well be the unfortunate result of low data variability concerning the mentioned predictors. also, the groups markedly differ in size (varying from 2 to 326 objects), which laid too much weight on the large æugroups (functioning as average) such as, for example, æu-54. this has a grave impact on the effectiveness of the classification of the combined samples which becomes much lower (table 9) and does not exceed 59%. figures 9a-d immediately disclose the symmetrical scattering of the æutica wells along both df2 or df3 axes which is in accordance to their permeability/porosity relationship. care must be taken here with distinction from case 1 as df2 and df3 do not weight depth against physical properties, while porosity on df3 exerts a slight negative correlation with permeability indices. in fig. 9c, some wells of the æutica field show the greatest shift from the group mean (as revealed previously in fig. 7) into the area of increased porosity/ permeability, while others from the same field are distinguished by the lowest porosity/permeability scores on the second axis. df3 is even less revealing and more should be expected only through the inspection of the discriminant score maps (created on the basis of table 8 ) which will be explained later (figs. 10a-c and 11ac). the scattering on the df2 and df3 has not much weight because the dwarfed discriminating potential of these axes should be obvious when comparing their relevant scales to that of the depth axis. 5. interpretation of results the results of all three cases have shown that, regardless of the angle from which the variation of the reservoir data can be studied and presented as a numerical model, depth will always emerge as a fundamental reservoir descriptor. this was to be expected under conditions of normal compaction. it is particularly evident when attempting to establish the interdependence between depth and substantial petrophysical properties over greater horizontal distances that embrace several widely scattered oil fields. in this case, the numerical models will tend to completely separate the two sets of descriptor variables of which one (porosity and permeability) belongs to the realm of intrinsic rock properties while the other (depth) is related to other causes, most fig. 9 comparison of combined groups within gss poljana: scatterplots of variable loadings (a, b) and of group means (c, d). 272 geologia croatica 54/2 likely tectonics. the spatial distribution of the latter obviously has much greater variability when mirrored in the, often subtle, changes of petrophysical data. if one should investigate and predict the reservoir performance solely on the basis of the depth-porosity relationship both internally and between as many as four oil and gas fields, with no linking data (e.g. from exploration wells), the attempt would be highly questionable due to the vast impact of the depth factor which would offset a commonly weak correlation of that variable with other reservoir descriptors. the effect is also aggravated if noise caused by short distance irregularities from wells is introduced into the scheme such as in case 3. thus, spatial (between-field) interdependence between depth and porosity/permeability can only be disclosed by a simultaneous review of the two computed functions in discriminant analysis, df1 and df2. case 1 is particularly instructive in this sense; with the æutica field as a pivot, with no distinctive depth and physical properties, other fields are arranged according to their weak but still observable inverse relationship. dugo selo is placed closest to the surface (df1=9.09) with the highest porosity/permeability indices (df2=0.41), while okoli is the deepest (df1=-1.64) with the lowest petrophysical qualities (df2=-0.84). struæec is somewhere in between (df1=3.99; df2=0.50). when interpretation is focused on vertical instead of horizontal distances, one can assess a more realistic representation of reservoir heterogeneity, because the actual spatial distribution of petrophysical attributes is spread through the same sedimentary sequence. when the sandstone units are correlated, depth and physical properties are directly linked to each other and one can more directly observe their inverse relationship. as expected, porosity and permeability features are reduced with increasing depth, which is directly observable from one and the same function computed in discriminant analysis for units (case 2). symbols in figs. 10a-c depict the spatial distribution of the wells of three fields æutica, okoli and struæec, where each symbol depicts the value of the group centroid on one of the three discriminant functions (df1-df3). as can be observed from the scatterplot in fig. 9a, the df1 function is strongly weighted with depth, which means that data from wells with negative values in fig. 10a are located at relatively greater depth compared to the entire data set. it can be observed that the cores from the okoli field wells are the deepest, those from the struæec field are the shallowest, while the data from the æutica field have a midrange of values. since this field is illustrated by the largest number of wells, and the classes with different symbols do not have equal span (see legend in fig. 10a), a local zonation becomes obvious. more precisely, it is observable that symbols in the centre of the southern part of the æutica structure correctly correspond to shallower locations than those in the peripheral parts of the field. exact df1 values are given in table 8. it can be presumed that the okoli and struæec fields would also exhibit a range of values if a larger number of wells would have been available and if they were more widely spaced. the map in fig. 10b depicts the regional distribution of the group centroids on the second discriminant function (df2). it is weighted with reservoir properties, strongly with porosity and mildly with both horizontal and vertical permeability (see in fig. 9a). simplified, this means that the specimens from the wells with increased df2 values are relatively more porous. in the okoli and struæec fields it can thus be observed that there is a porosity decrease in a se direction, and there is a local zonation in the æutica field area. in this field, there is a local area of increased porosity that is elongated nw-se and lies approximately between the southern and northern part of the æutica structure. there is also an area of reduced porosity along the sw margin of the field. if these relations are compared with the gss poljana isopach map (fig. 6) where the directions of palaeotransport are also marked, it becomes clear that the increased df2 values are located close to the transport channel axes which were drawn based on the thickness variations of both the entire interval of this genetic stratigraphic unit, and also on the variations of the total thickness of sandstone layers of this unit (safti∆, 1998; safti∆ & veli∆, 2000). this regularity can be explained by the fact that the transport channels were almost entirely filled with sandstones, and the thickest sandstone bodies are at the same time characterised by the highest level of sorting which results in maximal porosity values. regional distribution of the group centroids on the third discriminant function (df3) is illustrated in fig. 10c. it can be observed from fig. 9b that these values are proportional to the permeability and inversely proportional (but with less influence) to porosity. this can be read in such way that the increased df3 values depict the areas of high permeability. in fig. 10c, this is in the centre of the southern part of the æutica field, in the sw part of the okoli field and in the eastern part of struæec. it appears that df3 is spatially too variable to allow any conclusions regarding the okoli and struæec fields. however, similar layers in the okoli field (located 600 m deeper) show higher permeability than their counterparts overlying the top of the shallower struæec structure. it is also apparent that numerous wells of the æutica field show a distribution of df3 values which indicates that the most permeable parts are in the centre of the southern part of the field, which also represents the crest of an anticline, while the marginal parts of the field are less permeable. by comparison of this map (fig. 10c) with structure contours (fig. 4), isopachs of the kloπtar ivaniê formation (fig. 5) and of the gss poljana (fig. 6) it can be concluded that the regional distribution of permeability does not coincide with the 273saftiê, peh, veliê & jüttner: interdependence of petrophysical properties and depth... thickness of the unit but rather with structural highs. it is a known fact that the southern part of the æutica structure is in the gss poljana interval covered by only 40 m of sandstones (safti∆, 1993) and it can be observed from the e-logs that the permeability of these layers is occasionally really high. in the æutica field, favourable placement of wells with samples enabled construction of the df1-df3 contour maps (figs. 11a-c) which can actually be read as details of figs. 10a-c. the maps were created automatically, using pc and geological software. a relatively small area is shown (approx. 4x4 km, figs. 10a-c), and therefore the values were recalculated in a coarse regular grid of 25x25 nodes. for this calculation, the inverse distance method was used in all three cases. namely, it appeared that in this way calculated node values maximally honour the original values in the area surrounded by wells. from fig. 11a, which illustrates depth relations (as for fig. 10a), it can be observed that contour lines coincide with the structure contours of the southern part of æutica field as previously illustrated by the structure contour map (fig. 4). looking at the detailed spatial distribution of porosity (in fig. 11b), it is notable that the increased df2 values depict the extension of sandstone fill of one of the transport channels named “the main local transport channel”, which has already been drawn in the central part of the æutica field, based on the thickness variations of genetic units fig. 10 a) regional distribution of the group centroids on the first discriminant function (df1); b) regional distribution of the group centroids on the second discriminant function (df2); c) regional distribution of the group centroids on the third discriminant function (df3). 274 geologia croatica 54/2 and of their sandstone isolith (safti∆, 1993). the spatial distribution of df3 values (shown in fig. 11c), which is marked by permeability, is very variable. even at a local scale, it appears that there is no clear dependence between the permeability distribution and thickness of sandstone bodies. when compared with fig. 6 it can be seen that, regardless of the extensive area of increased thickness of gss poljana in the central part of the æutica field, there are significant changes of permeability along this “main local transport channel”. previous correlation indicated that sandstones of this unit are of a relatively homogeneous composition, which allows comparison of the spatial changes in architecture of each sandstone layer, based on the variations of the wireline log response (safti∆, 1993). therefore, spatial variations of permeability (figs. 10c and 11c) could be explained in two ways; either the apical parts of structures are usually slightly fractured due to strain, which causes an increase of permeability through microscopic fractures; or it is the result of the influence of stronger cementation in parts of the reservoir with increased circulation of pore water as opposed to areas at least partly saturated with hydrocarbons, or the permeability is originally smaller. as explained by tadej et al. (1996), it is therefore possible that originally “cleaner” and more permeable parts of sandstone layers become less permeable than the parts with a higher proportion of clayey and silty particles. 7. conclusions analysis of discriminant functions in four oil and gas fields dugo selo, æutica, okoli and struæec (case 1) has shown the following regularities. 94% of the variability of the entire system is related to depth. this means that differences between the fields are mostly marked with the depth of the studied reservoirs in a particular field. there is also an unusual reduction of the df2 group centroid values (marked with porosity) in the struæec field where reservoir layers are shallower in comparison to the deeper æutica field. no differences in architecture of sandstone layers that could explain this can be observed on the thickness maps or on wireline logs. the study of df3 (permeability) separated the dugo selo field (glwells) on the basis of its reduced permeability. the reservoirs of this field are much shallower than in the other three fields, which means that a substantial proportion of the permeability should have been preserved there. the reduced permeability is therefore explained by two facts the dugo selo field is quite distant from the other three studied fields, and it lies in the marginal part of the sava depression, where sandstone layers are thinner and are more poorly sorted. it is also interesting why only 8.42% of data from the okoli field are correctly classified (table 3). this may be explained by the great depth of the layers in this field, and the potential slowing of certain diagenetic processes. the okoli data here are more similar to the figs. 11 maps of æutica field spatial variation of the group centroids on discriminant functions df1 (a), df2 (b) and df3 (c). 275saftiê, peh, veliê & jüttner: interdependence of petrophysical properties and depth... properties in the 300 m shallower layers of the æutica field, which means that deeper emplacement did not affect the reservoir properties in this field and the pools retained the properties indicative of shallower layers. different properties within the three genetic stratigraphic sequences gss poljana, gss graberje and gss bregi (case 2), where only two discriminant functions were calculated, can not be discussed in more detail, because it showed that df2 has an insignificant interpretative value (only 0.1% of the system’s variabil ity), and the rest is connected with the depth. anyway, the units are in a sequence of superposition. there is a significant difference in classification of data from gss graberje in the okoli field. they appear to be either the deepest or of the poorest reservoir properties. this is caused by the different lithology of gss graberje, which is, in the okoli field area, composed of clayand silt-sized particles and contains no significant sandstone layers. in the lithostratigraphic system of units this is the area where, instead of the graberje member, its lateral equivalent named the graberje marl is present. this congruence is considered as an independent proof of the validity of this kind of statistical analysis. a combination of fields and wells (case 3) was aimed at depicting the regional distribution of the group centroids on three discriminant functions df1 (marked with depth), df2 (porosity) and df3 (permeability). it was established that df1 strongly separates the a priori defined groups, and that df2 and df3 have very weak influence (less than 2% of the system variance) which hinders any comparison apart from the ones within the margins of one particular field. certain regularities can also be spotted on the maps of regional distribution of the group centroids on all three discriminant functions. the values on the function which is marked with depth (df1) are such that, providing there are data from a larger number of wells, a zonation can be made within a particular field which conforms to structural relations. increased values of group centroids on the function which is marked with reservoir properties (mostly with porosity df2) are located close to the axes of palaeotransport channels. these channels were filled with the thickest sandstone bodies, with the highest level of particle sorting (coarsest grains) and the highest porosity. values on the third discriminant function (df3 proportional to permeability and inversely proportional to porosity but with lesser influence) show that permeability is not high in the areas where the genetic stratigraphic unit is the thickest but rather in the areas that coincide with the apical parts of structures. the differences may have been caused in two ways: either the crestal parts of the anticlines were fractured due to folding, or the lower parts experienced increased circulation of pore waters and therefore faster and stronger cementation. the distribution of group centroids and possibilities for zonation of these values much depend on the available number of wells (number of valid data and analysed samples). the spatial distribution of well data strongly affects interpretability, which means that it would be advisable to “activate” all the existing data and to systematically collect newly acquired information. there is a large data set of reservoir properties measured on horizontal cores in the ina naftaplin archives, but only the data that were within 10 cm vertical spacing were regarded as a set of three measurements porosity, horizontal and vertical permeability, that could be used in calculation, thus invalidating a large part of the data. experience has proved that many failures encountered in eor are due to poor understanding of the reservoir, particularly because of insufficient characterization. therefore the analysis of the spatial distribution of porosity and permeability is the most important issue in the description of the reservoir architecture, and in understanding of the geological model and fluid movement in the reservoir. a comparison between the regional distribution of petrophysical characteristics with lithological composition of the genetic stratigraphic units and with the interpreted palaeodrainage pattern of a submarine fan system, could be potentially useful in predicting both the reservoir behaviour and prospective areas for further exploration or infill drilling. acknowledgements the authors would firstly like to thank to dr.sc. slavka pfaff, who advised them in the statistical analysis techniques in the preparatory phase. secondly, the paper greatly benefited from the review by prof. patrick corbett, whose suggestions were partly comprehended as guidance for future work. a domestic review by dr.sc. boris vrbanac is also appreciated, as well as the financial support from the scientific projects 195018 and 195037 funded by the ministry of science and technology of the republic of croatia. 8. references bassiouni, z. & veli∆, j. (1996): prospecting for bypassed oil and gas.in: veli∆, j., hernitz, z. & safti∆, b. (eds.): proceedings of 1st international symposium of petroleum geology. economic aspects of petroleum exploration an approach to rational exploration. zagreb, april 18-19, 1996, geol. croat., 49/2, 197202. bauk, a. (1996): hydrocarbon reserves replacement methods and expenditures.in: veli∆, j., hernitz, z. & safti∆, b. (eds.): proceedings of 1st international symposium of petroleum geology. economic aspects of petroleum exploration an approach to rational exploration. zagreb, april 18-19, 1996, geol. croat., 49/2, 203209. bauk, a. & keber, d. (1980): karakteristike proizvodne razrade najznaëajnijih plinskih polja ina-naftaplina.struëni ëasopis dit, 2, 57-65, zagreb. 276 geologia croatica 54/2 bauk, a., saridja, v., »ubri∆, s. & gori»nik, b. (1988): novi pristup razradi leæiπta nafte i plina.nafta, 39/11-12, 659-672, zagreb. davis, j.c. (1986): statistics and data analysis in geology.2nd edition, john wiley & sons, new york, 646 p. dillon, w.r. & goldstein, m. (1984): multivariate analysis: methods and applications.john wiley & sons, new york, 575 p. gori»nik, b. (1981): rezultati laboratorijskih istraæivanja indiciraju realne moguênosti poveêanja iscrpka nafte primjenom nekih tercijarnih metoda u nas.struëni ëasopis dit, 6, 31-37, zagreb. gori»nik, b. & domitrovi∆, d. (1994): kontrola pokretljivosti plina pri procesu poveêanja proizvodnje nafte utiskivanjem ugljik dioksida.struëni ëasopis dit, 14/2, 71-76, zagreb. gori»nik, b., ∆elap, s., radionov, s., tomi∆, m., viplel, g. & rudan, s. (1978): eksperimentalno odreivanje utjecaja povrπinsko aktivnih tvari na poveêanje iscrpka nafte.zbornik radova simpozija “svojstva naftnih i plinskih leæiπta i njihov utjecaj na konaëni iscrpak”, znanstveni savjet za naftu jazu, 167-187, zagreb. gori»nik, b., peri∆, m. & sarapa, m. (1980): moguênost primjene tercijarnih metoda pri iskoriπtavanju naftnih leæiπta sr hrvatske.zbornik radova savjetovanja “nauëna i tehnoloπka istraæivanja u geologiji, rudarstvu i metalurgiji”, 871-833, neum. gori»nik, b., ∆elap, s., tomi∆, m. & sarapa, m. (1985): laboratorijska istraæivanja svojstva stijena i fluida leæiπta slavonsko-srijemske potoline.struëni ëasopis dit, 16, 35-45, zagreb. gori»nik, b., sarapa, m., csisko, m., peri∆, m., kulenovi∆, i. & zelenko, z. (1993): projekt istiskivanja nafte ugljik dioksidom laboratorijska istraæivanja, simulacija i tehnologija procesa.struëni ëasopis dit, 14/1, 76-90, zagreb. hernitz, z. & jurak, v. (1973): primjena paleostrukturne i statistiëke analize naslaga mlaega tercijara u podruëju ivaniê-grada (sjeverna hrvatska).nafta, 24/7, 343367, zagreb. jüttner, i. (1996): dry gas injection for miscible displacement on æutica oil field.in: veli∆, j., hernitz, z. & safti∆, b. (eds.): proceedings of 1st international symposium of petroleum geology. economic aspects of petroleum exploration an approach to rational exploration. zagreb, april 18-19, 1996, geol. croat., 49/2, 243247. jüttner, i. & rajkovi∆, d. (2001): economic and environmental aspects of enhanced oil recovery implementation.minerals & energy raw materials report, 16/1, 32-37, lulea univ. of technol., sweden. jüttner, i., safti∆, b. & veli∆, j. (1999): distribution of porosity and permeability within the pontian sandstones in the western part of sava depression in relation to their stratigraphic architecture, palaeotectonism and production of oil and gas.2nd international symposium of petroleum geology. probability approach to petroleum exploration. april 22-24, 1999, zagreb. working materials, 21-27, zagreb. jüttner, i., safti∆, b. & veli∆, j. (2001): distribution of porosity and permeability within the pontian sandstones in the western part of sava depression in relation to their stratigraphic architecture and palaeotectonic relations.nafta, zagreb (in press). kranjec, v. (1990): neke promjene ocrta dubinskogeoloπkih struktura i njihovo naftnogeoloπko znaëenje u savsko-dravskom podruëju i podmorju jadrana.rad jazu, 449, 195-225, zagreb. krizmani∆, k. (1980): odreivanje propusnosti stijena nosilaca ugljikovodika na osnovi kapilarnih pritisaka mjerenih metodom utiskivanja æive.nafta, 31/3, 122-134, zagreb. krizmani∆, k., abdulkarim, o., saad, s.f., mesmari, n. & el-ashahab, b.m. (2000): co2 f l o o d projects of clastic and carbonate reservoirs in the arabian gulf oil company libya.nafta, 51/7-8, 265-286, zagreb. krizmani∆, k., prni∆, æ. & nikoli∆, b. (1976): mjerenja i raëunanja relativnih propusnosti stijena nosilaca ugljikovodika.nafta, 27/9, 477-487, zagreb. lu»i∆, d., safti∆, b., krizmani∆, k., prelogovi∆, e., britvi∆, v., mesi∆, i. & tadej, j. (2001): the neogene evolution and hydrocarbon potential of the panonian basin in croatia.marine and petroleum geol., 18, 133-147. molak, b. (1977): kakve fizikalne pokazatelje stijena (propusnost, πupljikavost) moæemo oëekivati u pjeπëanim kolektorima ugljikovodika na veêim dubinama u jugozapadnom dijelu panonskog bazena.nafta, 28/12, 815-821, zagreb. peri∆, m., ten»i∆, m., kova», s. & bari∆, b. (1991): simulacijska studija primjenjivosti procesa istiskivanja nafte ugljik dioksidom na polju ivaniê-grad.nafta, 42/11, 445-458, zagreb. peri∆, m. (1992): uloga sekundarnih i tercijarnih metoda u poveêanju iscrpka ugljikovodika iz leæiπta.struëni ëasopis dit, 32, 7-13, zagreb. prelogovi∆, e. (1974): znaëenje klasifikacije neotektonskih struktura u paleotektonskoj rekonstrukciji.nafta, 25/10, 518-526, zagreb. prelogovi∆, e., safti∆, b., kuk, v., veli∆, j., draga©, m. & lu»i∆, d. (1998): tectonic activity in the croatian part of the pannonian basin.tectonophysics, 297, 283-293. safti∆, b. (1993): taloæni sustav pjeπëanih rezervoara genetske sekvencije slojeva pjeπëenjaka poljana u neogenskim naslagama polja æutica.unpublished m.sc. thesis (in croatian with an english abstract), faculty of mining, geology and petroleum engineering., university of zagreb, 55 p. safti∆, b. (1998): genetska stratigrafska sekvencijska analiza u pontskim naslagama zapadnoga dijela savske depresije.unpublished ph.d. thesis (in croatian with an english abstract), faculty of mining, geology and petroleum engineering., university of zagreb, 136 p. safti∆, b. & veli∆, j. (2000): genetic stratigraphic sequences in the upper miocene sediments of the sava basin.62nd eage conference and technical exhibition, 277saftiê, peh, veliê & jüttner: interdependence of petrophysical properties and depth... glasgow, scotland, 29 may 2 june 2000, extended abstracts book, 2, p-33, european association of geoscientists & engineers, houten. se»en, j. (1979): moguênost poveêanja iscrpka naftnih leæiπta u sr hrvatskoj.zbornik radova rudarsko-geoloπko-naftnog fakulteta sveuëiliπta u zagrebu u povodu 40 godina rada 1939-1979, 451-467, zagreb. se»en j. (1980): primjena dopunskih metoda eksploatacije (sekundarne i tercijarne metode).nafta, 31/7-8, 355-368, zagreb. se»en, j. (1987): moguênost daljnjeg poveêanja iscrpka nafte.struëni ëasopis dit, 21, 17-32, zagreb. se»en, j., vla©i∆, b., jan»ikovi∆, b. & »orak, v. (1988): veêom kvalitetom radova do novih zaliha ugljikovodika.nafta, 39/11-12, 641-649, zagreb. ©imon, j. (1970): prilog stratigrafskoj analizi tercijarnih sedimenata na sjeverozapadnom predjelu savske potoline.vii kongr. geol. sfrj, 1, 347-360, zagreb. tadej, j., mari∆-–urekovi∆, æ. & slavkovi∆, r. (1996): porosity, cementation, diagenesis and their influence on the productive capability of sandstone reservoirs in the sava depresion (croatia).in: veli∆, j., hernitz, z. & safti∆, b. (eds.): proceedings of 1st international symposium of petroleum geology. economic aspects of petroleum exploration an approach to rational exploration. zagreb, april 18-19, 1996, geol. croat., 49/2, 311-316. veli∆, j. (1979): o razlikovanju neotektonskih struktura u zapadnom dijelu savske depresije.geol. vjesnik, 31, 175-184, zagreb. veli∆, j. (1980): geoloπka graa zapadnog dijela savske depresije.unpublished ph.d. thesis (in croatian),faculty of mining, geology and petroleum engineering., university of zagreb, 137 p. veli∆, j. (1983): neotektonski odnosi i razvitak zapadnog dijela savske potoline.acta geol., 13/2, 1-39, zagreb. manuscript received march 14, 2001. revised manuscript accepted november 20, 2001. 278 geologia croatica 54/2 jurkovic.indd 241 � ab stra ct in palaeozoic rocks of south-eastern bosnia (seb) there are numerous, but very small vein and replacement barite ore deposits containing up to 10% pb-zn-fe-cu sulphides. their geochemical characteristics are compared with large barite monosulphide (hg-tetrahedrite) ore deposits in mid-bosnian schist mountains (mbsm). the 87sr/86sr isotope ratios in the barites of both areas are very similar, (0.710972 and 0.714170 in seb, 0.711764 and 0.712548 in mbsm), and indicate the epigenetic hydrothermal origin of the barite ore deposits. this conclusion is supported by the elevated sr content in barites of both areas (0.48 to 2.83% in seb, 1.44% in mbsm) and the δ13c and δ18o values in calcite and siderite of barite ore deposits which are shifted toward lower values relative to typical values occurring in the devonian host rock. the δ18o values in barites from seb (+14.2‰ to +15.6‰) are remarkably lower than those from mbsm (+15.8‰ to +22.4‰). this can be explained by the lower temperature and lower salinity of mineralisation fl uids in barite ore deposits of seb. the δ34s values in barites of seb are positive (+11.6‰ to 17.7‰), and enriched in heavy sulphur isotopes in comparison with sulphides of seb (–0.41 to +4.26‰), whereas those in tetrahedrites are negative (–4.95 in seb, –5.50 to –15.40‰ in mbsm) indicating two remarkably different sulphur sources and times of formation. barite ore deposits of both areas, seb and mbsm, have been genetically linked to fl uids that originated during late variscan s-type magmatism and metamorphism of upper proterozoic and lower palaeozoic rock complexes. however, later post variscan/eoalpine heating processes affected signifi cant parts of barite ore deposits in mbsm. they caused fl uidization of sulphides in barite deposits, ascension of subcrustal deepseated fl uids enriched in h2s and mercury (± fl uorine), which passed through upper proterozoic and caledonian ore deposits amalgamating their au and ag content leading to formation of a new mineral, hg-tetrahedrite rich in au (10–50 g/t) and ag (1000 do 3000g/t). keywords: palaeozoic complexes of south-eastern bosnia and mid-bosnian schist mountains, barite ore deposits, trace elements, isotopic composition of sulphur, oxygen and strontium in barite, pb-zn-fe-cu-sb sulphides, hg-tetrahedrite geochemical characteristics of barite occurrences in the palaeozoic complex of south-eastern bosnia and their relationship to the barite deposits of the mid-bosnian schist mountains � ivan jurković1, vesnica garašić1 and hazim hrvatović2 1faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, hr-10 000 zagreb, croatia; (vesnica.garasic@rgn.hr) 2federal geological institute, ustanička 11, ilidža, sarajevo, bosnia and herzegovina doi: 104154/gc.2010.20 geologia croatica 63/2 241–258 10 figs. 7 tabs. zagreb 2010 geologia croaticageologia croatica geologia croatica 63/2geologia croatica 242 1. introduction the biggest barite ore deposits in the whole dinarides are located in the mid-bosnian schist mountains (mbsm). this palaeozoic complex consists mostly of lower palaeozoic (ordovician(?)–silurian-devonian) rocks and subordinately of lower–middle carboniferous and upper permian rocks. these deposits are, regarding their mineral paragenesis, unique even on a global scale. the main mineral in the mineral paragenesis, in addition to barite and locally siderite, is hgag-au-rich antimony tetrahedrite, named schwazite after the schwaz locality, in austria. schneiderhöhn (1942) group ed this type of paragenesis as a separate genetic type. barite occurrences in the palaeozoic complex of southeastern bosnia (seb) represent the most south-eastern outcrops of numerous mineable barite deposits in the dinarides (fig. 1). compared to numerous geochemical data of barites from mbsm only a few geochemical analyses of barites from seb (pezdič et al., 1977/1979; kubat et al., 1979/ 1980) have been performed. the aim of this study is to present the more comprehensive geochemical data on barite occurrences in seb and compare them with those in the mbsm area. a model for the origin of the barite has been developed on the basis of trace elements, 87sr/86sr ratios, isotope composition of sulphur and oxygen in barites, carbon and oxygen in neocarbonates (neocalcite, neodolomite, neosiderite), and sulphur isotope composition in associated pb, zn, cu, sb and fe sulphides. research history of the barite occurrences in south-eastern bosnia initial data concerning the barite occurrences in south-eastern bosnia were described by jojić (1947), ra mović, m. (1954) and jeremić (1958). in the barite belt of reno vica-prača-omrke, which has a general nne-ssw trend, ramović, m. (1956, 1957) discovered three different paragenetic types of barite bodies (fig. 2a). jeremić (1963) registered 52 barite occurrences in palaeozoic rocks of seb (figs. 2b, 2c, 2d). most barite veins strike at 340o, dip more than 12o to ne, are very small (100 tons to a few thousand tons), and the total production from 1954–1966 was 24.000 tons of barite (ramović, m. et al., 1976; ramović, m. et al., 1979). kubat et al. (1979/1980) produced the fi rst isotopic sulphur analyses for pb and fe sulphides, barite, and 1 pb isotopic analysis for galena (pezdič et al., 1977/1979). ramovš & kulenović (1982) determined the stratigraphic position of mineralisation in sideritised limestones in the areas of šarulje-mastilove stijene, the kamenička river and milotina as being primarily lower devonian and to a lesser extent middle devonian. janjić & đorđević (1985) published results of isotopic analyses in minerals of ore deposits potkozara (kratina) and oglečevski potok (kordići). kulenović (1987) produced a brief overview of barite occurrences in seb, stating that deposits occur in a 15 km long and 3 to 6 km wide belt extending from fočanska jabuka in the south-west across borovac, klek and prača to renovica in the northeast (figs. 2e, 2f, 2g, 2h). ramović, e. (1991) published the project investigation of blečić (1983) on fl uid inclusions in sphalerite and barite in the ranoprge deposit, fl uid inclusions in quartz and δ34s of antimonite in kratina and kordići (goražđe). most researchers of seb consider that barite deposits originated in the hercynian metallogenic epoch probably associated with quartzporphyry being similar that quartz-porphyry in the mbsm (ramović, m., 1957; jeremić, 1963; živa nović, 1972; ramović, m. et al., 1976; ramović, m. et al., 1979). kulenović (1986, 1987) and čičić (2002) proposed a hypothesis suggesting the existence of more than one metallogenic epoch in the palaeozoic of seb indicating the probable existence of a caledonian metallogenic epoch (in the upper silurian and lower devonian). 2. geological setting the palaeozoic of seb is elaborated by katzer (1926), kostić–podgorska (1958), živanović (1962), dimitrijević, n.m. & dimitrijević, d.m. (1972), buzaljko & pamić (1982), vujnović (1983), ramovš & kulenović (1982), kulenović (1986), krstić et al. (1988), čičić (2002) & hrvatović (2006), and ramovš et al. (1984). the most detailed research resulting in many new palaeontological data was carried out by kulenović (1986), and produced evidence for upper silurian (s3), lower devonian (d1), middle devonian (d2), upper devonian (d3), lower carboniferous (c1) and upper permian (p3) deposits (fig. 3). upper silurian (s3) deposits, being <100 m thick, were found near prača and ustikolina, but the upper and lower boundaries are uncertain. they consist of silicic, clastic and fi gu re 1: the location of the palaeozoic complex of south-eastern bosnia (seb) in relation to palaeozoic complexes of the mid-bosnian schist mountains (mbsm), eastern bosnia (eb) and the una-sana area in bosnia and herzegovina. jurković et al.: geochemical characteristics of barite occurrences in the paleozoic complex of south-eastern bosnia... geologia croatica 243 fi gu re 2: barite occurrences in palaeozoic rocks of seb: a) lensoid barite bodies in limestone of kurjača, near prača (ramović, m. 1957); b) folded barite vein in schists of badnjevi, near prača (jeremić, 1963); c) brecciated barite body in limestone of debeljak, near prača (jeremić, 1963); d) crossed quartz and barite veins in silicifi ed breccia of ravne njive, near prača (jeremić, 1963); e) barite bodies in palaeozoic brecciated chert of gradina, in seb (kulenović, 1987); f ) barite bodies in palaeozoic rocks of homar klek, in seb (kulenović, 1987) where 1 = gray metasandstone, 2 = barite bodies, 3 = brecciated barite, 4 = alevrolite, 5 = red sandstone; g) barite bodies in palaeozoic gray metasandstone of rasoha-jasik, in seb (kule nović, 1987); h) barite body in palaeozoic rocks of šušnjata glava in seb (kulenović, 1987). a) b) c) d) e) f ) g) h) geologia croatica 63/2geologia croatica 244 dolomitic limestone rock with conodonts. sedimentation from the upper silurian continued into the lower devonian, but transitional deposits (s3–d1) could not be separated. sequences are composed of alevrolites, cherts, argilloschists, metasandstones, tuffi tes and marbleized limestone (kulenović, 1986). the lower devonian consists of alevrolites with chert (either independent small masses or intercalations in alevrolites), layered and bank limestones. this lower part of the lower devonian is overlain by sequences composed of cherts, diverse argilloschists, metasandstones and limestones among which very fossiliferous bank limestones occur. chert breccias, metadiabases, schistose spilites, diabases and some red clastites are locally developed. according to kule nović (1986) granitoides occurring in the odska river and osanica, intruded between lower and upper devonian or in the upper devonian. the upper devonian is composed of limestone schists, cherts, chert breccias, ferrous sandstone and marbleized limestones. tabular sericite-quartz schists mark the lower part of the lower carboniferous. they are overlain by phyllite schists with intercalations or lenses of schistose sandstones containing fossil fl ora of lower visean age. fossiliferous lower carboniferous phyllites with black lydite inter calations are the next deposits in the sequence (kulenović, 1986). the uppermost, unfossiliferous part of the phyllite schists represents, the transition from the lower to middle carboniferous according to kulenović (1986). these are discordantly overlain by deposits of upper permian sandstones, schists, conglomerates and fossil-rich bellerophone limestones. krstić et al. (1988) discovered olistoliths and olistostromes composed of limestones and clastics in the "culm fl ysch" in the prača area. they stated that olistostrome formation is associated with very active tectonic zones, which caused the shearing and movement of large blocks such as vlaška stijena, kiseljak, klek and some others. čičić (2002) and hrvatović (2006) presented short over views of the stratigraphic development of quartz-porphyry in seb. the most widespread rocks of the mid-bosnian schist mountains (mbsm) are pre–devonian metamorphic rocks (sofilj et al., 1980). majer et al. (1991) determined that they were formed by low grade metamorphism at 350°– fi gu re 3: geological map of the area between fočanska jabuka and prača (after kulenović, 1986). circles denote the locations of barite samples analyzed here, whereas rectangles represent locations, which are undergoing analysis. t1–2 = lower-middle triassic; p3 = upper permian; c1–2 = lower-middle carboniferous; d3 = upper devonian; d2 = middle devonian; d1 = lower devonian; s3– d1 = upper silurian-lower devonian; s3 = upper silurian; γ = granitoid. jurković et al.: geochemical characteristics of barite occurrences in the paleozoic complex of south-eastern bosnia... geologia croatica 245 400°c and a pressure of 3–5 kbars. their crystallization age, obtained by k–ar dating is 343 ± 13 ma (palinkaš et al., 1996). fossiliferous devonian carbonate rocks overlie this metamorphic complex (živanović, 1972). the uplift of this area is related to the hercynian orogeny and extrusions of rhyolites. upper permian continental and lagoonal deposits that unconformably overlie older palaeozoic rocks, grade into lower and middle triassic sediments. mineralization in the seb palaeozoic complex comprises small, but numerous barite deposits. they occur as irregular metasomatic barite bodies and epigenetic veins in the carbonate rocks, and contain traces or accessory amounts of pb, zn, and subordinantly cu and fe sulphides (fig 4). additionally, they occur as epigenetic barite veins located in metaclastites but enriched in sulphides (up to 10%). all sulphides have positive δ34s values (0 to +5‰). the rare younger hg–ag tetrahedrite is characterized by a negative δ34s value (–4.95‰). the hg–ag–au tetrahedrite deposits in the mbsm represent a peculiar and unique phenomenon in the whole dinarides (katzer, 1907; jurković, 1956). the mačkara vein type is observed in pre–devonian metamorphic rocks of the gornji vakuf area (jurković, 1960; jurković et al., 1994). the kreševo vein and metasomatic irregular bodies are very widespread in the area composed of devonian dolomites and limestones (jurković, 1996). the trošnik metasomatic type that occurs in the fojnica– bakovići area represents, at present, a unique exception among tetrahedrite-bearing barite deposits in mbsm. its tetrahedrite is neither the main nor the unique sulphide mineral rich in mercury, but is subordinate to pyrite and chalcopyrite and characterized by traces of mercury and positive δ34scdt values (jurković, 1958). 3. analytical methods ore samples were collected from seven outcrops in seb and ten outcrops in mbsm. barites were hand-picked under binocular microscope and then crushed and powdered for chemical analyses in an agate mortar. trace elements were analysed by inductively coupled plasma (icp) mass spectrometry in acme analytical laboratories (vancouver) ltd in canada. in order to use x-ray powder diffractometry (xrd), barite samples were powdered in an agate mortar. diffractograms were recorded by a philips diffractometer with counter and cu-kα radiation at u =40 kv and i = 20 ma at the institute of mineralogy, petrology and mineral resources at faculty for mining, geology fi gu re 4: photographs of white barite occurrences: a) in permian limestone of datelji; b) in carboniferous schists of pale; c) in devonian limestone of the glumac deposit (kreševo); d) in devonian limestone of the dubrave deposit (kreševo). note hammer for the scale. a) b) c) d) geologia croatica 63/2geologia croatica 246 table 1: trace element contents of barites from seb and mbsm. mbsm seb seb seb seb seb seb mbsm seb sample k d s dp j p fc range ppm ppm ppm ppm ppm ppm ppm ppm ppm ba >50000 >50000 >50000 >50000 >50000 >50000 >50000 be <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 co 0.3 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 cs 0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 ga <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 hf 0.5 0.4 0.3 0.3 0.3 0.7 0.6 0.5 0.3–0.7 nb <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 rb 0.4 0.3 0.1 0.2 0.2 0.2 <0.1 0.4 <0.1–0.3 sn <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 sr 14354 12201 4846 6158 18888 7650 28292 14354 4846–28992 ta 1.4 0.9 0.8 0.8 0.9 1.7 1.7 1.4 0.8–1.7 th <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 u <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 v 13 10 <8.0 <8.0 <8.0 <8.0 <8.0 13 <8–10 w <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 zr 1.6 0.4 <0.1 <0.1 0.2 0.2 1.4 1.6 <0.1–1.4 y 1.0 0.7 0.9 0.5 0.6 1.2 1.3 1.0 0.5–1.3 la 2.4 1.6 1.4 1.8 1.7 1.1 3.5 2.4 1.1–3.5 ce 0.9 0.3 0.2 0.2 0.3 0.2 0.7 0.9 0.2–0.7 pr 0.10 0.04 0.03 0.04 0.04 0.03 0.06 0.10 0.03–0.06 nd 0.3 <0.3 <0.3 <0.3 <0.3 <0.3 <0.3 sm 0.45 0.33 0.35 0.25 0.30 0.58 0.67 0.45 <0.25–0.67 eu 0.85 <0.02 0.04 0.24 <0.02 1.03 1.00 0.85 <0.02–2.03 gd 1.02 0.80 0.81 0.70 0.68 1.44 1.62 1.02 0.68–1.62 tb 0.08 0.06 0.06 0.05 0.05 0.10 0.10 0.08 0.05–0.10 dy 2.78 2.20 2.09 1.76 1.74 3.80 4.05 2.78 1.74–4.05 ho <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 er 0.03 <0.03 <0.03 <0.03 <0.03 <0.03 <0.03 tm 0.02 0.11 0.01 <0.01 <0.01 0.03 0.03 0.02 0.01–0.11 yb 0.07 <0.05 0.06 <0.05 <0.05 0.06 0.08 0.07 <0.05–0.08 lu <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 mo 0.20 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 cu 3.90 1.40 1.60 0.30 2.30 18.10 0.80 3.90 0.3–18.1 pb 2.40 1.20 4.50 11.20 4.30 0.40 0.50 2.40 0.4–11.2 zn 6.00 1.00 1.00 <1 2.00 1.00 <1 6.00 <1–2 ag <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 ni 0.90 0.20 0.30 0.10 0.20 <0.1 <0.1 0.90 <0.01–0.3 as <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 au <0.0005 <0.0005 0.00120 <0.0005 <0.0005 <0.0005 <0.0005 cd <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 sb 0.30 0.10 0.10 1.20 0.10 0.90 0.20 0.30 0.1–0.2 bi <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 hg 0.19 0.09 1.66 0.42 0.63 0.22 0.03 0.19 0.03–1.66 tl <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 se <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 ca 300.00 500.00 1.31 0.01 <0.1 <0.1 <0.1 300.00 <0.01–13100 σree 9.03 5.87 5.41 5.46 5.25 8.73 12.17 lan/ybn 24.59 22.95 16.74 25.82 24.39 13.15 31.38 eu/eu* 19.08 0.46 0.91 5.97 0.45 24.17 23.04 ce/ce* 0.47 0.12 0.08 0.08 0.12 0.09 0.24 jurković et al.: geochemical characteristics of barite occurrences in the paleozoic complex of south-eastern bosnia... geologia croatica 247 and petroleum engineering at the university of zagreb. carbon, sulphur and oxygen isotopes were determined at the stable isotope laboratory of the university of lausanne using the finnigan mat facility. strontium isotopic ratios were determined by thermal ionisation mass spectrometry (tims) in the activation laboratory ltd in anchaster (ontario). 4. results 4.1. trace element composition of barite samples trace elements were analysed in six samples of pure barite from the prača-foča area in seb and in one sample of pure barite from the glumac deposit in the kreševo area (k) in mbsm. barite samples in seb were collected in the šarulje (š), jabukovik (j), pale (p), datelji (d), dragosin potok (dp) and fočanska jabuka (fj) barite deposits. the trace element contents of the analysed barites are listed in table 1. they are generally present in very low concentrations. the values of 15 trace elements (be, ga, nb, sn, th, u, w, ho, lu, ag, as, cd, bi, ti, se) are below the detection limits of the analytical method in both areas. five trace elements (cs, co, nd, mo, er) only occur in the glumac deposit (mbsm), whereas au (1.2 ppm) is only detected in the šarulje deposit (seb). of the 24 trace elements detected in the barites of both areas, 16 show similar values in both seb and mbsm, 6 are slightly higher in mbsm and 2 trace elements (zn and ni) are signifi cantly higher in mbsm (table 1). rees are present in very low concentrations. maximum total ree contents range from 5.25 to 12.17 ppm. (table 1). the chondrite normalized (sun & mcdonough, 1989) ree patterns of all analysed barites are shown in fig. 5. the ree patterns are characterized by an enrichment of the lree against the hree such as ho, er, tm, yb and lu (minimal lan/ybn = 13.15 to 31.38). the tm values in all barite deposits excluding jabukovik and dragosin potok deposits are an exception to this statement. the ree patterns of all barite samples display a negative ce anomaly (ce/ce* = 0.08 to 0.47). signifi cant difference in the ree patterns of studied barites is visible only in eu anomaly. barites of the jabukovik, datelji and šarulje deposits are characterised by a negative eu anomaly (eu/eu* = 0.45; 0.46 and 0.91 respectively), whereas those of the dragosin potok, pale, fočanska jabuka and kreševo deposits show positive anomaly (eu/eu* = 5.97; 24.17; 23.04; 19.08 respectively). 4.2. ca content in barites minor substitution of ca for ba in the crystal lattice of barite is often observed. in the studied barites, the highest ca content is found in the barite from the šarulje deposit (1.31 %). the barite from the datelji deposit contains 0.05 % ca, in kreševo area 0.03 % ca and the barite from dragosin potok only 0.01 % ca. other studied barites are characterized by a ca content which is below the detection limits of 0.01 % (table 1). the x-ray analyses of the barites from šarulje, datelji and the kreševo area reveal the presence of calcite as individual phase only in the barite from the šarulje deposit (3.24 % caco3). the ca content in other ca bearing barites is most probably substituted for ba in the crystal lattice. consequently, the barite from the datelji deposit contains 0.17 % caso4, 0.10% in the kreševo area and the barite from dragosin potok has 0.03 % caso4 component. 4.3. sr content in barites in comparison to other foreign elements in the crystal lattice of barite, sr is evidently enriched in all the studied barite. its content varies from 0.48 to 2.83 % in the barites of seb and in the barite from mbsm it is 1.44 % (table 2). the sr content of barites in table 2 is additionally expressed as a srso4 component. the obtained sr value for barite of mbsm is in agreement with sr values for 22 barite samples already published by jurković et al. (1997), which range from 0.48 to 3.15% sr (average 2.0%). the x-ray analyses of the barites revealed that their sr content is the lowest in šarulje deposit, the middle in kreševo area and the highest in fočanska jabuka deposit, and demonstrated that strontianite (srco3) as an individual phase does not exist in the barites. accordingly, the presence of sr in the barites could be explained by its substitution for ba in the crystal lattice, and expressed as a srso4 component. such a relatively high sr content is typical for an ascending hydrothermal type of mineralization, whereas a low sr content characterizes the volcano-sedimentary type of barite deposits. fi gu re 5: plot of rare-earth elements normalized to c1 chondrites (sun & mcdonough, 1989). legend: šarulje (s), jabukovik (j), pale (p), datelji (d), dragosin potok (dp), fočanska jabuka (fj) and kreševo (k). table 2: content of sr and srso4 in barite. sample sr (%) srso4 (%) k 1.44 3.03 d 1.22 2.56 s 0.48 1.03 dp 0.62 1.30 j 1.89 3.96 p 0.77 1.60 fc 2.83 5.93 geologia croatica 63/2geologia croatica 248 4.4. isotopic composition of sulphur (as sulphate) and oxygen in barites the isotopes are analysed not only in the barites of previously mentioned localities in seb and kreševo area, but also in some other barite deposits in mbsm (table 3). sulphur isotope data in table 3 are expressed relative to canon diablo troilite and oxygen isotope data relative to vienna standard mean ocean water. the sulphur isotopes (δ34s) in the barites from seb span a narrow range, from +11.6‰ to +17.7‰ (mean +14.4‰). the only available δ34s analysis of the barite from the šarulje deposit (pezdič et al., 1977/1979; kubat et al., 1979, 1980) has a value of 12.4‰ and fi ts very well into the range determined here. barites from mbsm also display a narrow range of δ34s values, varying between +10.1‰ and +16.8‰ (mean value = +11.8‰). this data is in accordance with the earlier published δ34s values from 22 barite samples from mbsm (jurković et al., 1997), which vary from +8.05‰ to +18.48‰ (mean value = +11.5‰). regarding only the mean values, the barites from mbsm are characterized by a slight enrichment of the light sulphur isotope compared to the barites from seb. the oxygen isotope values (δ18o) shown in table 3 represent the fi rst δ18o data for selected barites in the dinarides. the barites from seb have δ18o values within a narrow range, from +14.2‰ to +15.6‰ (mean +14.7‰). the barite samples from mbsm reveal remarkably higher δ18o values ranging from +15.8‰ to +22.4‰ (mean +18.47‰). the sulphur and the oxygen isotope data of the barites investigated in this study are summarized in fig. 6. 4.5. isotopic composition of carbon and oxygen in neominerals from seb the carbon (δ13c) and oxygen (δ18o) isotope ratios in the neominerals of the barite deposits from seb are represented in table 4. the δ13c values are expressed relative to the vienna peedee belemnite standard (vpdb) and the δ18o values relative to both the vienna peedee belemnite standard (vpdb) and the vienna standard mean ocean water (smow). the values of δ13c measured in the microcrystalline siderite from šarulje deposit and in the "red spar" siderite from ljaljice (fočanska jabuka) deposit are –7.60‰ and –3.22‰ respectively. the coarse crystallised calcite from the dragosin potok deposit has a positive δ13c value (+0.19‰). the δ18ovpdb values are negative for all examined minerals and range from –6.5‰ to –9.90‰ (table 4). the data are in agreement with previously published δ13c and δ18o values for neominerals occurring in the devonian host rock of other deposits in bosnia. for the purpose of comparison, data published by janjić & đorđević (1985) and jurković et al. (1997) are listed in table 4. 4.6. strontium isotope ratios in the barites and the metarhyolite the strontium isotope ratios (87sr/86sr) in the barites are listed in table 5. the 87sr/86sr values in the barites of seb are 0.710972 and 0.714170 and are very similar to those in the barites from mbsm (0.711764 and 0.712548). such sr ratios in the barites from both areas are more radiogenic, when compared to the values between 0.70680 and 0.70925, which characterize coeval seawater, rocks and fossils from lower cambrian to upper permian (gradstein et al., 2006). the 87sr/86sr value of the metarhyolite from the vranica mountain in mbsm is extremely high (0.776995). table 3: sulphur and oxygen isotope data in the barites from seb and mbsm. sample δ34scdt δ34sstd δ18ovsmow δ18ostd locality sign seb datelji d 13.1 0.0 14.8 0.1 ljaljice lj-1 17.6 0.2 15.6 <0.5 jabukovik j 16.7 0.2 15.3 0.3 fočanska j. fc 17.7 0.2 15.1 0.1 šarulje s 14.4 0.5 14.4 0.2 dragosin p. dp 11.6 0.0 15.3 0.2 pale p 12.2 0.3 14.2 0.0 šarulje, glav.* 12.4 mbsm mačkara 1 mc-1 11.6 <0.3 17.6 <0.5 kreševo k 10.8 0.2 19.7 0.2 rijetka kosa rik 11.4 <0.3 21.7 <0.5 otunjski vis otv 10.1 <0.3 16.3 <0.5 sabiljine p. sbp 11.2 0.15 15.8 <0.5 vrelo-1 vrl-1 11.7 <0.3 18.0 <0.5 selakova k. sek 16.8 0.18 16.1 <0.5 medenik-1 med-1 10.8 <0.3 22.4 <0.5 medenik 2 med-2 12.1 <0.3 21.2 <0.5 mačkara-2 mac 11.7 <0.3 16.1 <0.5 šarulje, glav.*= δ34s analyse made by pezdič et al. (1977/1979) fi gu re 6: comparison of sulphur and oxygen isotope data in the barites from seb and mbsm. jurković et al.: geochemical characteristics of barite occurrences in the paleozoic complex of south-eastern bosnia... geologia croatica 249 5. discussion the discussion is focused on conclusions of the newly obtained geochemical data on barite and those previously published by numerous authors (palinkaš & jurković, 1994; jur ković et al., 1997; strmić et al., 2000; palin kaš et al., 2001; jurković & palinkaš, 2002; pa linkaš et al., 2008). typical devonian barite deposits with pb, zn, and fe sulphides in the palaeozoic area of graz (austria) belong to the synsedimentary volcanogenic type of barite deposit and were used here as geochemical parameter to distinguish syngenetic from hydrothermal-epigenetic type of barite deposits. additionally, the comparison is related to the geochemical investigations of the brixlegg ore deposit, tyrol, austria (schulz, 1972; gstrein, 1979; schroll & pak, 1980; frimmel & papesch, 1990; ebner et al., 1999), and the rudnany ore deposit, gemericum unit, slovakia (cambell et al., 1985; žak et al., 1991; radvanec et. al., 2004). besides the bosnian tetrahedrite occurrences, these represent the most important european hg-ag-sb tetrahedrite ore deposits, and are included into the discussion. 5.1. ree the low total ree concentrations, light ree enriched chondrite normalized ree patterns and negative ce anomaly determined in the barites are usually interpreted as an indication of a hydrothermally infl uenced seawater fl uid component in the barite origin (guichard et al., 1979; murray et al., 1990). the most signifi cant difference in the shape of ree patterns is expressed in the eu-anomaly that is positive for barites from dragosin potok, pale, fočanska jabuka and kreševo area, and negative for the barites from the šarulje, datelji and jabukovik deposits. this indicates the presence of two different sources of hydrothermal fl uids. spatially large (up to 1 km long) but poor barite ore deposits associated with siderite and fe-, cu-, pb-, znand sbsulphides in the area of šarulje, mastilove stijene, kamenička river and milotina, are especially interesting from the genetic point of view. according to kulenović (1987), these are stratabound types of deposits. the 87sr/86sr ratio of barite from šarulje (table 5) indicates an epigenetic type of formation. the investigation will try to resolve the ambiguity based on more precious ree analyses and 87sr/86sr ratios in barite and host rock (devonian dolomite). 5.2. 87sr/86sr ratio the rb/sr ratios in the investigated barites from both the, seb and mbsm, are very low (table 1). accordingly, the initial 87sr/86sr ratios of the barites have not signifi cantly increased since the time of crystallization and refl ect the composition of the host fl uids. the signifi cantly higher 87sr/86sr ratios of the barites from seb and mbsm (0.710972 to 0.714170) relative to those of contemporaneous seawater, rocks and fossils from lower cambrian to upper permian (0.70680 and 0.70925, after gradstein et al., 2006), suggest hydrothermal fl uids and an epigenetic origin of bosnian barites. the higher recorded 87sr/86sr ratios of the rocks through which hydrothermal fl uids have circulated suggest an evolved crustal source for ba, sr and rb. an extremly high 87sr/86sr ratio of metarhyolite (0.776995) indicates a crustal source for the rhyolite magma (s-type of granitoid magma). table 4: isotopic composition of carbon and oxygen in the neominerals from seb and their comparation with already published analyses of the same type in seb and mbsm. sample type of mineral/ δ13cvpdb δ13cstd δ18ovpdb δ18ovsmow δ18ostd locality sign deposit rock ‰ ‰ ‰ seb dragosin p. dp barite calcite +0.19 0.06 –6.50 +24.2 0.12 šarulje s barite siderite –7.60 0.04 –6.83 +23.9 0.05 ljajice lj barite siderite –3.22 0.10 –9.90 +20.7 0.12 seb* kratina stibnite dolosparite –1.10 to –2.02 kordići microsparite –0.66 to –1.53 –11.60 to –12.73 mbsm** gornji v. zec mountain barite/ tetrahedrite calcite –2.62 to +1.20 –8.32 to –6.66 deževica kreševo siderite –5.55 to +1.01 –8.82 to –10.33 * analyses published by janjić & đorđević, 1985. **analyses published by jurković et al., 1997. table 5: strontium isotope analyses in the barites from seb and mbsm and metarhyolite. sample mineral/rock 87sr/86sr locality sign value +/– 2s seb šarulje š barite 0.710972 6 ljajice lj-1 barite 0.714170 5 mbsm kreševo k barite 0.712548 8 mačkara mac barite 0.711764 4 vranica d1 metarhyolite 0.776995 5 geologia croatica 63/2geologia croatica 250 the comparison of 87sr/86sr ratio in barites from seb and mbsm and those from the brixlegg, graz and rudnany deposits are shown in fig. 7a. 5.3. srso4 content in barite the relationhips between the srso4 content in barites of bosnia and some other worldwide known barite deposits are shown in fig. 7b. the srso4 content in barites depends signifi cantly on the genetic type of barite deposit. for instance, the palaeozoic barites from graz (austria) belong to the synsedimentary volcanogenic type of barite deposit and have low srso4 contents (0.6 to 1.6 wt%). devonian barites of the same genetic type in meggen and rammelsberg deposits, also have low srso4 contents (0.23–0.59 wt%). in contrast, barites of bosnia and also those of the brixlegg (bx) deposit in austria and the rudnany (rd) deposit in slovakia are characterized by considerably higher srso4 contents (0.9 to 5.01 wt% and 0.8 to 3.2 wt%, respectively), which are typical for hydrothermal epigenetic deposits. extended rang es of srso4 contents could be the result of partial remobilization processes during the hercynian and alpine orogeny. 5.4. δ13c and δ18ovpdb of the main host-rock and neominerals the δ13c and δ18ovpdb values determined in neominerals of devonian rocks hosting different barite deposits in bosnia, have been compared with those being typical for primary devonian dolomite, and are shown in figs. 8a and 8b. in primary devonian dolomite the typical δ13c values range from +0.5‰ to +3‰ and the δ18ovpdb values between –3.5‰ and –7.0‰ (gradstein et al., 2006). carbon and oxygen isotope values of all neominerals in the devonian dolomites are shifted relative to these typical values toward lower values as clearly demonstrated in fig. 8. this indicates a change in the isotopic characteristics of devonian host rocks during mineralization and points to the epigenetic origin of barite deposits. the isotopic data of carbon and oxygen of previous investigators, (presented in table 4), also suggests the same conclusion. the comparison of δ13c and δ18osmow ratio in siderites from seb and mbsm and those from the brixlegg, graz and rudnany deposits are shown in figs. 9a and 9b. fi gu re 7: comparison of 87sr/86sr ratio, srso4 %, δ34s and δ18o values in barites from seb and mbsm and those from brixlegg (bx), graz (gz) and rudnany deposits (rd): a) besides 87sr/86sr ratio in barites, typical values of 87sr/86sr ratio in devonian dolomite (d) and in strontianite (srco3) and in celestine (srso4) of rudnany deposit are shown too; b) the srso4 content in barites; c) measured δ34s values in barites where ht = hydrothermal barite; s = sedimentary barite, vs = volcanogenic-sedimentary barite; d) measured δ18o values in barite. fi gu re 8: comparison of δ13c (a) and δ18ovpdb (b) values of neominerals in devonian rocks hosting diff erent barite deposits in bosnia and those being typical for primary devonian dolomite. a) b) c) d) a) b) jurković et al.: geochemical characteristics of barite occurrences in the paleozoic complex of south-eastern bosnia... geologia croatica 251 5.5. δ34s in barites and sulphides most barite deposits in mbsm contain tetrahedrite as the sole ore mineral. measured δ34s values in 18 samples of hg tetrahedrite in mbsm range from –5.50‰ to –15.40‰ (mean values −10.49‰). the δ34s values in 3 pyrite samples from the same deposits are –0.7‰, –4.6‰ and –9.86‰ (šiftar, 1988, 1990). distinctively, the tetrahedrite from the trošnik (foj nica) deposit, which has a minimal content of hg, gave positive δ34s values (+3.28‰ and +3.73‰), as did another sulphide mineral in this deposit (kubat et al., 1979/1980). the measurements of δ34s values in antimonite in the čemernica deposit gave +3.48‰, +2.12‰ and +2.21‰ and in sphalerite +3.71‰ (kubat et al., 1979/1980). obviously, two different sulphur sources were included in the genesis of sulphide minerals in mbsm. the δ34s values in barites are characterized relative to these sulphides by a signifi cant enrichment of the heavy sulphur isotope (+10.1‰ to +16.8‰). hg-tetrahedrite also occurs in the barite deposits in seb, but as a minor component. its δ34s values are also negative (–4.95%, fočanska jabuka). the main ore minerals are galena, sphalerite and pyrite, and chalcopyrite is subordinate. according to kubat et al. (1979/1980) the δ34s values of these sulphides range from –0.5 to +4.5‰ (table 6). compared to these data, the δ34s values in barites are enriched by heavy sulphur isotope (as in the barite deposits in mbsm). two isotopically different types of sulphide also occur in the rudnany deposit. the main ore minerals are hg-tetrahedrite and chalcopyrite, which have markedly negative δ34s values (fig. 10). in contrast, pyrite and cinnabar have positive δ34s values (cambell et al., 1985). according to žak et al. (1991) and grecula et al. (1991) negative δ34s values in tetrahedrite and chalcopyrite are consequences of isotope fractionation between h2s, (derived from deepseated fl uids) and so4 2–, (derived from the permian sea water). in palaeozoic strata of graz, galena, sphalerite and pyrite occur, and they exhibit relatively high positive δ34s values ranging from +2.5‰ to +13.2‰ (pak et al., 1980). data are not available for the brixlegg deposit where hg-tetrahedrite is the sole ore mineral and other sulphides only occur as accessory minerals δ34s. analysis of tetrahedrite from schwaz, tyrol (obtained from professor prohaska (leoben) revealed a negative δ34s value (–1.60‰). comparison of the sulphur isotopic composition in sulphide minerals from different barite deposits in seb, mbsm, graz and rudnany is shown in figs. 10a and 10b. positive δ34s values in sulphides of both barite deposits from seb (table 6) and polymetallic sulphide deposits from mbsm (kubat et al., 1979/1980), and also positive δ34s values in barites from barite deposits in seb and mbsm indicate that one of the sources of the sulphur in these deposits could be older lower palaeozoic stratiform volcano-sedimentary sulphide deposits. studies of such a type of sulphide deposit were undertaken on the lower palaeozoic series of gemericum in slovakia. they revealed δ34s values ranging between +2‰ to +15‰ (kantor & rybay, 1970; radvanec et al., 1992). there are still no measurements of δ34s values in lower palaeozoic stratiform volcano-sedimentary sulphide deposits in the dinarides. variscan metamorphism caused the circulation of hydrothermal fl uids that remobilized sulphur from the lower palaeozoic and older stratiform volcano-sedimentary sulphide deposits and led to the formation of the younger sulphide deposits. the obvious enrichment of heavy sulphur isotopes in barites compared with those in sulphides in the barite deposits of both, seb and mbsm, indicates retrograde variscan metamorphism and infl uence of the sulphate derived sulphur from the permian sea. 5.6. δ18ovpdb, smow in barites and fl uid inclusions the δ18o values in barites in seb (+14.2‰ to +15.6‰) are very similar to those in the brixlegg and rudnany barite defi gu re 9: comparison of δ13c (a) and δ18osmow (b) values in siderites from seb and mbsm and those from the brixlegg, graz and rudnany deposits where cp = typical carboniferous-permian values. table 6: sulphur isotope data for sulphides in barite deposits of seb (kubat et al.,1979/80) locality mineral δ34s (‰) ranoprge galena +3.04 chalcopyrite +2.49 pyrite +2.80 kurjača galena +0.34 šarulje galena +0.53 kopilovo galena –0.41 pyrite +1.44 goražde stibnite +1.21 stibnite +2.29 stibnite +4.26 a) b) geologia croatica 63/2geologia croatica 252 posits (fig. 7). remarkably higher δ18o values occur in barite samples from mbsm (+15.8‰ to +22.4‰ ). according to ramović e. (1991) the only fl uid inclusion study in barite deposits in seb was that of blečić (1983), who discovered primary fl uid inclusions in the barite in the pb-zn deposit in ranoprge (fočanska jabuka) and determined th between +110ºc and +140ºc and a salinity of 10 wt% nacl equ. in the last 15 years, numerous fl uid inclusion studies were carried out in ore deposits (mostly barite deposits) of palaeozoic complexes in mbsm (palinkaš & jurković, 1994; jurković & palinkaš, 1999; strmić et al., 2000; palinkaš et al., 2001; jurković & palinkaš, 2002; palinkaš et al., 2008). the results of all these studies demonstrated higher salinity 24.2 do 26.3 wt% nacl equ. in kreševo and 32.6 to 32.9 wt% nacl equ. in raštelica. analyses of fl uid inclusions of these authors in barites of barite deposits in mbsm revealed higher homogenisation temperatures (+210ºc to +310ºc in kreševo area, +230ºc to 270ºc and 320º to +350ºc in the raštelica deposit. there is a clear correlation between lower δ18o values and lower th of fl uid inclusions in barite deposits from seb relative to higher δ18o values and higher th of fl uid inclusions in barite deposits from the mbsm. this is in agreement with the statement of hoefs (1997) who stated that mineralisation fl uids of higher temperature are characterized by higher salinity and higher δ18o values. the process of barite mineralisation in the brixlegg deposit took place at temperatures ranging from +70ºc to 130ºc (frimmel, 1991). in rudnany, (a vein ore deposit consisting of siderite, barite, tetrahedrite and chalcopyrite), the study of fl uid inclusions determined th varying between +150ºc and +300ºc (radvanec et al., 2004). 5.7. origin of the barium-strontium bearing hydrothermal fl uids the 87sr/86sr ratios determined in the barites (0.710972 to 0.714170) from both seb and mbsm are high. the high ba content and high 87sr/86sr ratio in the mineralisation fl uid could be achieved by hydrothermal leaching of rb-rich altered felsic rock. according to frimmel & papesch (1990) the high 87sr/86sr ratios are typical for fl uids being connected to s-type magmatism and/or being crustal contaminated by circulation through rb-rich clastites and extrusive magmatic rocks. until 1969 or 1972 respectively it was believed that the carbonate sequences of jezero (jajce) and vranica mountain were of upper carboniferous to lower permian age (katz er, 1926). rhyolitic magmatism occurred in the middle and upper permian and partly in the triassic (katzer, 1926). jurković & majer (1954) found signs of contact metamorphism at the contact between the rhyolite and these carbonate rocks on the vranica mountain and sinjakovo, concluding that the rhyolite is of upper carboniferous to middle permian age. mudrenović et al. (1969) however, found silurian-devonian conodonts in limestones in the jezero area (jajce). based on devonian fossils on the vranica mountain, however, the age boundary of rhyolite to middle-upper carboniferous-lower permian has been revised (živanović, 1972). according to hrva tović (1996, 2006) rhyolites are the product of two stage volcanic activity. most of them are synsedimentary with metasediments of presumed silurian age. some hypabyssal rhyolites intruded into late silurian and early devonian limestones, which also occur as xenoliths within the volcanic bodies. hrvatović marked the upper permian as the upper boundary of rhyolite age, while he observed a large quantity of quartz-porphyry pebbles in basal breccias and conglomerates of discordant upper permian formation of kruščica mt. the basal discordant breccias, with quartz-porphyry fragments, were previously observed by jeremić (1963). petrological studies of the rhyolites of sinjakovo and vranica mt. were undertaken by jurković & majer (1954) and majer & garašić (2001). jurković & majer (1954) determined the leucogranite or albite granitic character of the rhyolite magma. majer & garašić (2001) identifi ed the peraluminous character of the rhyolite of vranica mountain (pi = 1.9–4.1). the low content of compatible trace elements and high contents of incompatible trace elements indicate a crustal magmatic origin. additionally, the authors concluded that relationships between rb, y and nb suggest a syncollisional origin of the rhyolite magma. in the same sample of metarhyolite being studied by majer & garašić (2001) we determined an extremely high 87sr/86sr ratio (0.776995 ±2s), confi rming the hypothesis of a crustal origin of the rhyolite magma. in slavonian s-granites (psunj, papuk and krndija mountain), lanphere & pamić (1992) discovered that the 87sr/86sr ratio corresponds to a value of 0.72539±17, while in the moslavačka mountain it is 0.74302±5. an unusual spectrum of paragenetic types of ore deposits (jurković, 1956) supfi gu re 10: comparison of δ34s values in tetrahedrites and other sulphides from seb, mbsm and those from the brixlegg, graz and rudnany deposits where t = tetrahedrite, ch = chalcopyrite, py = pyrite, ss = sedimentary sulphides, hs = hydrothermal sulphides, vss = volcanogenic-sedimentary sulphides. a) b) jurković et al.: geochemical characteristics of barite occurrences in the paleozoic complex of south-eastern bosnia... geologia croatica 253 ports the presence of an s-type granite in mbsm. ore deposits of ba and subordinately of fe (barite, siderite, ankerite, pyrite and stibnite) dominate. all other ore deposits of cu, pb, zn and as are very small and their minerals are subordinate to barite and siderite ore deposits. metals, typical for i-type magma (sn, w, mo, f, b, li) occur very rarely, only as occurrences of mineralogical importance. 5.8. genetic model for the formation of the baritesulphide deposits in the palaeozoic complexes of mbsm and seb on the basis of geological and geochemical data comprising former investigations and data determined in this study, it can be concluded that barite ore deposits in seb and mbsm had been formed by hydrothermal fl uids,linked to magmatic and metamorphic processes and infl uenced by permian seawater. the following phases of hydrothermal mineralisation have been recognized in the seb and mbsm area: a) early variscan phase which is not the subject of this study; b) late variscan phase which is responsible for the origin of barite ore deposits containing fe-, cu-, zn-, pband sb(as) sulphides with positive δ34scdt values; c) post-variscan (early eoalpine) phase which affected the existing late variscan barite ± siderite ore deposits with mercury-bearing fl uids associated with the processes of degassing of the upper mantle, and leading to formation of hg-, agand au-rich tetrahedrites showing negative δ34scdt values. degassing pro cesses were linked to the early phase of the permo-triassic intercontinental rifting. late variscan phase. in the whole of the dinarides, barite ore deposits were formed in the late stage of the variscan cycle and are located in the upper silurian, devonian, carboniferous and permian rocks. ore mineralisation in the clastites is usually present in the form of veins or impregnations, whereas in carbonate rocks it occurs as irregular bodies or replacement nests. barite is the dominant mineral, quartz is subordinate and siderite and calcite occur only locally. sulphides of fe, cu, zn, pb, sb and as occur in very variable mutual relationships, ranging from trace amounts up to 10 %, but all have positive δ34s values. the form of occurrence and geochemical data of the studied barite ore deposits indicate their epigenetic nature and origin, caused by circulation of hydrothermal fl uids which were related to late stage variscan metamorphism and magmatism and infl uenced by permian seawater. the bulk of the late variscan barite ore deposits were formed most likely in lower permian time. most of the barite ore deposits in mbsm experienced processes of regeneration and remobilisation in the postvariscan stage. only rare barite deposits have been partly or completely preserved. the trošnik deposit is a very good example of a preserved type of barite ore deposit, located near fojnica in the ne part of mbsm. it occurs in a predevonian complex of rocks. the paragenesis of the deposits contain pyrite and chalcopyrite as the main minerals, whereas siderite and quartz occur as gangue minerals. sband fe-rich tetrahedrite occurs too, but contains only traces of hg and has positive δ34s values (+3.23‰ to +3.73‰, kubat et al., 1979/1980). a very similar result (+4.0‰) was produced in the current analysis of this tetrahedrite. barite ore deposits in seb, however, have been almost completely preserved in their primary state. they are small but numerous, characterized by fe-, cu-, zn-, pband sbsulphides, but do not contain au, only small amounts of ag. a post-variscan overprint characterized by the formation of au-, hg-tetrahedrite having negative δ34s values (–4.95‰) is only locally present (fočanska jabuka, šarulje). geochemical differences between barite ore deposits in mbsm and seb are summarized in table 7. monosulphide hg-tetrahedrite barite ore deposits in mbsm differ from polysulphide barite ore deposits in seb in having: a) more positive δ18o values in barites, b) lower δ34s values in barites, c) pronouncedly negative δ34s values in hg-tetrahedrite, d) signifi cantly higher homogenisation temperature and higher salinity in fl uid inclusions of barites, quartzes and fl uorites. regarding the connection of other ore deposits in dinarides with the late variscan phase, it should be emphasized that at the end of the lower permian, continental or shallow marine clastic sediments of the grödener formation were formed under a warm arid climate. these sediments are widespread in the dinarides and are according to jurković & palinkaš (1996) bearers of uranium (žirovski vrh, slovenia), copper (cerkno-sava fold, slovenia; vitezustiprača, monte negro) and low manganese haematite ore deposits (mokronog-hrastno, slovenia; rude, croatia; bukovica, croatia). these deposits are described by drovenik et al. (1980), šinkovec (1971), čop et al. (1998), and kulenović (1987). the middle permian sediments grade upwards into the upper permian shallow marine evaporite and carbonate sediments, (the bellerophon formation), or locally into the sabkha transition zone or continental red beds. an early diagenetic sabkha type deposit is described by palinkaš et al. (1993). most of the upper permian evaporites occur on tectonic lines along the una, sana, vrbas and bosna rivers, and in the mostar, sinj, knin and drniš areas. upper permian evaporites are characterized by a mean δ34s value of + 11‰ (jurković & šiftar, 1995). the post-variscan/ eoalpine phase. strong magmatic activity (rhyolites, keratophyres, diabases) took place during the permian period, especially in the asslian-sakmarian stages. pamić et al. (2004) using k-ar method determined the age of metadiabase (287.8 ± 11.1 ma) and ortho-greenschist (268.7 ± 10.2 ma) at bradine (ivan mt., mbsm) and connected their results to post-variscan magmatism. using the same method on the same rock types, the authors determined a cooling phase which lasted until the triassic (247.0 ± 9.5 ma; 238.4 ± 9.2 ma). the results support the heating event during upper permian time in the mbsm. heating of some parts of the crust in the dinarides during the middle/upper permian enabled lateral (extensional) movements of the continental crust and the rise of upper mantle fl uids. the optimum geotectonic environments in the geologia croatica 63/2geologia croatica 254 dinarides developed along a permo-triassic intracontinental rift. contemporaneously, former late palaeozoic faults, the western voljevac fault and eastern busovača fault, as well as a dense framework of faults of lower order between them, had been reactivated. the geotectonic conditions facilitated penetration of mercury (± fl uorine)-bearing fl uids from deep levels of the upper mantle to higher levels of the crust. karamata et al. (1995) emphasized that the highest concentration of mercury in former yugoslavia occurred in the triassic mineralization of the dinarides (mercury deposits idrija, tršće, spič, draževići, kovač mt). independently of this statement, jurković & palinkaš (1996) wrote ”fluorine and mercury bounded to the hg-tetrahedrite in the mbsm were probably derived at least partially from the uppermost zone of the mantle”. on their way to upper levels fl uids passed through upper proterozoic and caledonian au and agbearing ore deposits, and hg being present in fl uids amalgamated with the au and ag. at still higher levels, these fl uids reached barite ore deposits being formed in the late variscan phase. there, most of the primary sulphides have been fl uidized, and a new mineral, hgtetrahedrite, rich in au (10–50 g/t) and ag (1000 do 3000g/t) was formed. results of 183 mercury-bearing minerals analysed from the ore deposits of the dinarides suggested the conclusion that isomorphic substitution of mercury into the host minerals decreased in the following order: sphalerite → tetrahedrite → gold/silver → pyrite → galena → realgar → antimonite (karamata et al., 1995). this is in agreement with the situation in the mbsm. strongly negative δ34s values of hg-tetrahedrite in mbsm ore deposits were explained by remobilization of isotopically light sulphur of biogenic origin from the middle/upper permian stratiform u-cu (±fe) ore deposits in the dinarides and/or from older similar genetic types of ore deposits. the role of isotope fractionation between ascending deep-seated h2s and descending so4 2– from permian seawater is not excluded. the early phase of intracontinental rifting: controversial opinions exist concerning the beginning of the alpine cycle. cassinis et al. (1975) and wopfner (1984) considered that the hiatus between the lower and middle permian sedimentary cycles separates the variscan cycle from the overlying alpine cycle. krainer (1993) considers the rifting processes during the middle triassic as indicating the beginning of the alpine cycle. the contemporaneous nature of the early phase of the intracontinental rifting and the beginning of the alpine cycle in the dinarides is emphasised here, because the permian/ triassic boundary (251 ma) has a well documented suite of table 7: summarized geochemical data from barite ore deposits in seb and mbsm. geochemical data ore area n late variscan n post variscan/eoalpine authors th (homogenisation temperature) seb +110ºc to +140ºc blečić (1983) mbsm +190ºc to +140ºc (kreševo) +210ºc to +250ºc ; +320ºc to +350ºc (raštelica) palinkaš & jurković (1994) strmić et al. (2000) salinity wt% nacl equ. seb ~ 10 wt% blečić (1983) mbsm 24.2 to 32.9 wt% palinkaš & jurković (1994) strmić et al. (2000) % srso4 in barites seb 6 1.03 to 5.93 (2.73)% this work mbsm 1 23 3.03 % 1.60 to 6.60 (4.22)% this work jurković et al. (1997) δ34scdt in barites seb 7 +11.6 to +17.7 (+14.61) ‰ this work mbsm 10 +10.1 to +16.8 (+11.80) ‰ this work δ18ovsmow in barites seb 7 +14.2 to 15.6 (+14.7) ‰ this work mbsm 10 +15.8 to +22.4 (+18.50) ‰ this work δ34scdt in tetrahedrites seb 1 –4.95 ‰ kubat et al. (1979/80) mbsm 18 –5.5 to –15.4 (–10.49) ‰ jurković et al. (1997) δ34scdt in fe-cu-zn-pb-sb sulphides seb 10 –0.41 to +4.26 ‰ kubat et al. (1979/80) mbsm –4.55 ‰ jurković et al. (1997) δ13cvpdb in neocarbonates seb 3 –7.60 to +0.19‰ this work mbsm +1.20 to –5.50 (–2.12) ‰ jurković et al. (1997) δ18osmow in neocarbonates seb 3 +20.7 to +24.2 ‰ this work mbsm +23.7 to +29.1 ‰ jurković et al. (1997) 87sr/86sr ratio seb 2 0.710972 and 0.714170 this work mbsm 2 0.711764 and 0.712548 this work jurković et al.: geochemical characteristics of barite occurrences in the paleozoic complex of south-eastern bosnia... geologia croatica 255 chemical evidence supported by global correlation (gradstein et al., 2006). the most important are as follows: a) an extraordinarily fast rise in the δ34s of sea water sulphate, ranging from +8 up to +12‰ to +20 up to +29‰ between the middle and upper lower triassic (245 ma) termed the “roet event” (nielsen, 1965; rick, 1990); b) global cooling and the beginning of mass extinction coincide with the remarkable increase in 87sr/86sr values from 0.7068 to 0.7080 from the end of the capitanian (260ma) to the upper permian-lower triassic boundary (251 ma) (martin & macdougall, 1995). korte et al. (2003) consider that this event may be a response to increased continental weathering following glacial climates of the early permian. c) the end-permian mass extinction coincides with an abrupt negative shift of 4% in values of carbon isotopes in marine and terrestrial settings, probably caused by decreased marine production and an infl ux of light carbon from volcanic, soil-carbon or a methanogenic source (sephtone et al, 2002). the triassic period begins just after this carbon minimum (erwin, 1995) d) large scale global shifts to higher δ18o values in carbonates indicate a general progressive change from the late permian through the triassic and are interpreted as the result of cooler sea water or a glacial episode suggesting a total cooling of 4°c in tropical seas (wallman, 2001). 6. conclusion geochemical investigations of barites revealed: (1) trace element compositions in barites from both area (seb and mbsm) are very similar indicating a unique ore bearing area with the infl uence of seawater on hydrothermal barite origin. (2) barites of both areas show elevated sr content (0.48 to 2.83% in barites from seb, 1.44% in barite from mbsm), typical for epigenetic hydrothermal barite ore deposits. the sr substitues for ba in the crystal lattice. (3) the 87sr/86sr isotope ratios in the barites of both areas are similar (0.710972 and 0.714170 in barites from seb, 0.711764 and 0.712548 in barites from mbsm) and are more radiogenic in comparison with values which characterize coeval seawater, rocks and fossils from lower cambrian to upper permian (0.70680 to 0.70925). this also indicates an epigenetic hydrothermal origin of barite ore deposits. (4) very high 87sr/86sr isotope ratio (0.776995) determined in a rhyolite sample from vranica mt. (mbsm) confi rms the origin of rhyolite magma by crustal anatexis. (5) the δ13c and δ18o values in calcite, dolomite and siderite of barite ore deposits are shifted toward lower values relative to typical values occurring in devonian host rock, also indicating an epigenetic origin of barite ore deposits. (6) the δ18o values in barites in seb (+14.2‰ to +15.6‰) are remarkably lower than δ18o values of barite samples from the mbsm (+15.8‰ to +22.4‰). this can be explained by a lower temperature and lower salinity of mineralisation fl uids in barite ore deposits of seb (hoefs, 1997). (7) the barite ore deposits of seb are characterized by δ34s values which are positive (+11.6‰ to +17.7‰) and enriched in heavy sulphur isotope in barites in comparison with sulphides (–0.41 to +4.26‰), and negative in tetrahedrite (–4.95‰). this indicates three different sulphur sources for barite ore deposits in seb. the same is true for δ34s values in barite ore deposits of mbsm (+10.1 to +16.8‰ in barites, –9.86 to –0.71‰ in pyrites, –5.50 to –15.40‰ in tetrahedrites). the source of heavy sulphur isotope in fe, cu, zn, pb, sb sulphides and in barites is deep seated, linked to caledonian, neoproterozoic and early palaeozoic sulphide deposits. the δ34s values of barites of the late variscan deposits have been infl uenced by permian sea-water sulphate. this infl uence was stronger in the barites of the post-variscan phase. in contrast the very light sulphur isotope in hg-tetrahedrites is probably of biogenic origin and/or a consequence of isotope fractionation between h2s derived from deeper seated upper mantle fl uids and so4 2–, derived from the permian evaporites. (8) in both ore areas of bosnia, seb and mbsm, two paragenetic types of barite ore deposits were determined. the older type originated in the late variscan phase (lower permian) and the younger one in the post variscan/early eoalpine phase. the older type of barite ore deposit contains more than 90% barite, small amounts of quartz, locally siderite and calcite, and polysulphides (fe-, cu-, pb-, znand sb(as)–sulphides), the amount of which depends on the host rock (5–10% in clastites, 1–2% in carbonate rocks). this type dominates in seb, and very rarely shows signs of the post-variscan overpint. in the mbsm area, it only occurs in the trošnik deposit and partly altered in the jezero area (jajce). all other barite ore deposits in mbsm (kreševo, kiseljak, zec and pogorelica mt., gornji vakuf, medenik) were overprinted during the post-variscan phase and have the genetic characteristics of a younger regenerated type of barite ore deposit. the younger type of barite ore deposit is characterized by monosulphide (au-, agand hg-rich tetrahedrite). other sulphides, mainly cu-sulphosalts, only occur in trace amo unts. this tetrahedrite has been formed by regeneration and fl uidization of sulphides of older types of barite ore deposit with a supply of hg, au, ag and f from the mantle and/ or amalgamation of au and ag from caledonian and older ore deposits. the younger type of barite ore deposit occurs only sporadically in seb (fočanska jabuka) and then as younger barite veins and nests with hg tetrahedrite having negative δ34s (–4.95‰). acknowledgement we would like to thank ladislav palinkaš and vladimir bermanec who critically reviewed an earlier version of this manuscript. references blečić, a. (1983): ispitivanje izotopa sumpora, kisika i ugljika u antimonskim ležištima potkozara i kordići [examination of sulphur, oxygen and carbon isotope in antimony deposits of potkozara and kordići – in croatian].– in: ramović, e. (1991): metalogenija bosne i hercegovine [metallogeny of bosnia and herzegovina – in croatian].– unpubl. phd thesis, faculty of mining, geology and petroleum engineering, university of zagreb, 239 p. geologia croatica 63/2geologia croatica 256 buzaljko, r. & pamić, j. (1982): osnovna geološka karta sfrj 1:100000, tumač za list foča [basic geological map of sfry 1:100000, geology of the foča sheet – in croatian].– savezni geološki zavod, beograd, 61 p. cambel, b. & jarkovský., j. (1985): rudnianske rudne pole – geochemicko-metalogeneticka charakteristika [the rudnany ore fi eld – geochemical and metallogenetic characteristics – in slovakian].– veda vydavatelstvo slovenskej akadémie vied, bratislava, 363 p. cassinis, g, elter, g., rau, h. & tongiorni, m. (1979): verrucano: a tectofacies of the alpine-mediterraneas southern europe.– memorie della societa geologica italiana, 20, 135–149. čičić, s. (2002): geološki sastav i tektonika bosne i hercegovine [geological composition and tectonics of bosnia and herzegovina – in croatian].– earth science institute, sarajevo, 350 p. čop, m., jurković, i. & slovenec, d. (1998): sedimentary lowmanganese hematite deposits of the bukovaca area in the north western mt. petrova gora, central croatia.– rudarsko-geološkonaftni zbornik, 10, 1–24. dimitrijević, m.n. & dimitrijević, m.d. (1972): kulmski fl iš okoline prače [culm flysch of the prača area – in serbian].– vii. kongres geologa sfrj (7th national congress of geologists), knj. ii, zagreb, 59–72. drovenik, m., pleničar, i. & drovenik, f. (1980): origin of ore deposits in sr slovenian.– geologija, 23, 1–157. ebner, f., cerny, i., eichhorn, r., götzinger, m.a., paar, w.h., prochaska, w. & weber, l. (1999): mineral resources in the eastern alps and adjoining areas.– in: neubauer, f. & höck, v. (eds.): aspects of geology in austria.– austrian journal of earth sciences, 92, 157–184. erwin, d.h. (1995): the end-permian mass extinction.– in: sholla, p.a., peryt, t.m. & ulmer-scholle, d.s. (eds.): the permian of northern pangea. springer-verlag, berlin, 1, 20–34. frimmel, h.e. (1991): isotope constraints on fl uid rock ratios in carbonate rocks: barite–sulfi de mineralization in the schwaz dolomite, tyrol (eastern alps, austria).– chemical geology, 90, 195–209. frimmel, h.e. & papesch, w. (1990): sr, o and c isotope study of the brixlegg barite deposit, tyrol (austria).– economic geology, 85, 1162–1171. gradstein, f., ogg, j. & smith, a. (2006): a geologic time scale.– cambridge, university press, 589 p. gstrein, p. (1979): neuerkenntnisse über die genese der fahlerzlagerstätte schwaz (tirol). – mineralium deposita, 14, 185–194. grecula, p., radvanec, m. & bartolsky, b. (1991): critical thermic isograde in metamorphic-hydrothermal model of vein mineralization on the back ground of the variscan events; gemeric unit, western carpathians.– newsletters, no 3, project igcp no 276, mineralia slovaca, 23, 403–411. guichard, f., church, t.m., treuil, m. & jaffrezic, h. (1979): rare earths in barites: distribution and effects on aqueous partitioning.– geochimica et cosmochimica acta, 43, 983–997. hoefs, j. (1997): stable isotope geochemistry.– 4th completely revised, updated and enlarged edition. springer verlag, berlin, 201 p. hrvatović, h. (1996): strukturno–facijalna analiza sjeverozapadnog škriljavog gorja [structural and facies analysis of the mid-bosnian schist mts. – in bosnian].– unpubl. phd thesis, university of tuzla, 112 p. janjić, s. & djordjević, d. (1985): rezultati ispitivanja sb–minerala iz područja goražda (ji bosna) [the results of investigation of sb minerals from the goražde area (se bosnia) – in serbian].– zbornik radova, tehnički fakultet i institut za bakar, bor, 21/1, 41–56. jeremić, m. (1958): baritska ležišta jugoslavije i mogućnost njihovog razvoja [barite deposits of yugoslavia and the possibility of their development – in serbian].– tehnika 3, 401–412. jeremić, m. (1963): metalogenija paleozojskih ležišta barita bosne [metallogeny of palaeozoic barite deposits of bosnia – in serbian].– technologica acta, 1/2, 1–60. jojić, d. (1947): pregled nalazišta barita na području nr bih [overview of barite deposits in the area of bosnia and herzegovina – in serbian].– fond stručnih dokumenata, geoinženjering, sarajevo, 1–7. jurković, i. (1956): mineralne parageneze srednjobosanskog rudogorja s osobitim osvrtom na tetraedrite [mineral paragenesis of midbosnian ore mountains with special review of tetrahedrite – in croatian].– unpubl. phd thesis, faculty of engineering, university of zagreb, 550 p. jurković, i. (1958): tetraedrit iz rudne pojave trošnik kraj fojnice u srednjobosanskom rudogorju [tetraedrite from the ore deposit of trošnik near fojnica in the mid-bosnian ore mountains – in croatian].– geološki glasnik, 4, 221–246. jurković, i. (1960): quecksilberfahlerz vom mačkaragang bei gornji vakuf in bosnien (jugoslawien).– neues jhrb. d. mineral., 94, 539– 558. jurković, i. (1996): barite, hematite and cinnabar ore deposits in the dusina area, mid–bosnian schist mountains.– rudarsko-geološkonaftni zbornik, 8, 51–65. jurković, i. & majer, v. (1954): rioliti (kremeni porfi ri) vranice planine i albitski riolit sinjakova u srednjobosanskom rudogorju [rhyolithe (quartzporphyre) des vranica – gebirges und albit– rhyolit (quartzkeratophyr) von sinjakovo im mittelbosnischen erzgebirge – in serbian].– vesnik zavoda za geološka i geofi zička istraživanja rn srbije, knjiga xi, 207–233. jurković, i. & palinkaš, l. (1996): late variscan, middle-upperpermian, post-variscan and triassic rifting related ore deposits in the northwestern and central dinarides.– proceeding of the annual meeting, unesco project no. 356, plate tectonic aspects of the alpine metallogeny in the carpatho-balkan region, sofi a, 1, 19–27. jurković, i. & palinkaš, l. (1999): sulphur isotope and fl uid inclusion data of barites from the dinarides.– in: stanley, c. j. et al. (eds.): mineral deposits, processes to processing – 6th biennal meeting of sga and iagod, london 1999, proceedings, balkema publication, rotterdam, 45–49. jurković, i. & palinkaš, l. (2002): discrimination criteria for assigning ore deposits located in the dinaridic palaeozoic-triassic formations to variscan or alpidic metallogeny.– in: blundell, d. j. neubauer, f. & von quade, a. (eds.): the timing and location of major ore deposits in an orogen. geological society, london, special publications, 204, 229–245. jurković, i. & šiftar, d. (1995): sulphate sulphur. isotope composition of evaporites in the western dinarides.– in: pašava, j, kribak, b. & žak, k. (eds.): mineral deposites: from origin to their environmental impacts. a.a. balkema, rotterdam, 581–584. jurković, i., pezdič, j. & šiftar, d. (1994): geology and geochemistry of the mineralization from the gornji vakuf area, bosnia.– rudarsko-geološko-naftni zbornik, 6, 19–37. jurković, i., palinkaš, l., slovenec, d., šiftar, d., miko, s., jakšić, m. & pezdič, j. (1997): geochemical characteristics of mercurian tetrahedrites from the middle bosnian schist mountains.– in: papunen, e. (ed.): mineral deposit: research and exploration. where do they meet? – 4th biennal sga meeting, turku, finland, august 1997, a.a. balkema, rotterdam, 829–832. kantor, j. & rybay, m. (1970): radiometric ages and polyphase character of gemeride granites.– geologicky zbornik – geologica carphatica, 4, 433–448. karamata, s., ozerova, n.a. & janković, s. (1995): metallogenic aspects of mercury geochemistry in ore deposits of the central part of the balkan peninsula.– geological society of greece, spec. publ., athens, 4, 741–746. jurković et al.: geochemical characteristics of barite occurrences in the paleozoic complex of south-eastern bosnia... geologia croatica 257 katzer, f. (1907): die fahlerz–und quecksilbererzlagerstätten bosniens und der hercegovina.– manzsche k. u. k. hof-verlags und universitäts buchhandlung i., kohlmarkt, 20, 1–122. katzer, f. (1926): geologie bosniens und der herzegovina.– erster band, i. u. ii. hälte, sarajevo. korte, c., kozur, h.w., brucksehen, p. & veizer, j. (2003): strontium isotope evolution of late permian and triassic seawater.– gechimica et cosmochimica acta, 67, 47–62. kostić-podgorska, v. (1958): fauna i biostratigrafski odnosi paleozojskih tvorevina u okolini prače [fauna und biostratigraphic relationship of palaeozoic formations in prača area – in serbian]. – glasnik zavoda za geološka istraživanja, sarajevo, 4, 1–220. krainer, k. (1993): late and post-variscan sediments of the eastern and southern alpes.– in: raumer, l., & neubauer, f. (eds.): pre-mesozoic geology in the alps.– springer-verlag, 32, 537–564. krstić, b., filipović, i. & maslarević, lj. (1988): palaeozoic olistostromes of prača area, se bosnia.– geološki anali balk. poluostrva, beograd, tom li, 223–229. kubat, i., ramović, e., tomičević, d., pezdič, j. & dole nec, t. (1979/1980): rezultati ispitivanja izotopskog sastava sumpora, kiseonika, ugljenika i olova u nekim rudnim ležištima i pojavama bosne i hercegovine [the results of the investigations of s, o, c and pb isotopic composition in some ore deposits and occurrences in bosnia and herzegovina – in serbian].– geološki glasnik, 24/25, 61–84. kulenović, e. (1986): paleozoik jugoistočne bosne [palaeozoic of south-eastern bosnia – in serbian].– unpubl. phd thesis, faculty of natural sciences and engineering, edvard kardelj university, ljubljana, 151 p. kulenović, e. (1987): mineralizacije u paleozoiku jugoistočne bosne [mineralisations in palaeozoic of south-eastern bosnia– in serbian].– geološki glasnik, 31/31, 106–143. lanphere & pamić (1992): k-ar and rb-sr ages of alpine granitemetamorphic complexes in the northwestern dinarides and the southwestern part of the pannonian basin in northern croatia.– acta geologica, 22/2, 97–111. majer, v., lugović, b. & trubelja, f. (1991): metamorphism of the midd–bosnian schist mountains – a preliminary investigation (in croatian).– radovi anubih, sarajevo, 87/13 141–158. majer, v. & garašić, v. (2001): metarioliti vranice planine u paleozoiku središnje bosne [metarhyolites of vranica mountais in paleozoic of middle bosnian – in croatian].– rudarsko-geološko-naftni zbornik, 13, 9–14. martin, e.e. & macdougal, j.dr. (1995): sr and nd isotopes at the permian/triassic boundary: a record of climate change.– chemical geology, 125, 1/2, 73–99. mudrenović, v., stojanović–kuzenko, s. & pajić, v. (1969): razvoj silura i devona u području jezera kod jajca (z. bosna).– iii simpozij dinarske asocijacije, institut za geološka istraživanja, zagreb, 135–146. murray, r.w., buchholtz ten brink, m.r., jones, d.l., gerlach, d.c. & russ iii, g.p. (1990): rare earth elements as indicators of different marine depositional environments in chert and shale.– geology, 18, 268–271. nielsen, h. (1965): schwefelisotope in marinen kreislauf und das δ34s der früheren meere.– tsch. rundschau, 55, 160–172. pak, e., schroll, e. & weber, l. (1980): zur schwefelisotopenzusammensetzung der pb–zn vererzung des grazer paläozoikums (ostalpen).– mineralium deposita, 15, 315–325. palinkaš, l. & jurković, i. (1994): lanthanide geochemistry and fl uid inclusion peculiarities of the fl uorite from the barite deposits south of kreševo (bosnia and herzegovina).– geol. croat., 47/1, 103–115. palinkaš, l.a., pezdič, j. & šinkovec, b. (1993): the lokve barite deposit: an example of early diagenetic sedimentary ore deposits.– geol. croat., 46/1, 97–106. palinkaš, l.a., majer, v., balogh, kad., bermanec, v. & jurković, i. (1996): geochronometry and termochronometry of the metamorphism in the inner dinarides, mbsm.– annual meeting of unesco igcp project, no 356, sofi a, 1. palinkaš, l.a., strmić, s., jurković, i. & hrvatović, h. (2001): epithermal gold deposits in central bosnia.– geode workshop "geodynamics and ore deposits evolution of the abcd– province", vata bai, romania, june 2001. romanian journal of mineral deposits, bucharest, 79/2, 77. palinkaš, l.a., borojević-šoštarić, s. strmić-palinkaš, s. (2008): metallogeny of the northwestern and central dinarides and southern tisia.– ore geology reviews, 34/3, 501–520. pamić, j., balogh, k., hrvatović, h., balen, d., jurković, i. palinkaš, l. (2004): k-ar and ar-ar dating of the palaeozoic metamorphic complex from the mid-bosnian schist mts., central dinarides, bosnia and herzegovina.– mineralogy and petrology, 82, 65–79. pezdič, j., perko, s., weiss, a. & popović, s. (1977/79): izotopne analize sumpora u galenitu, halkopiritu, piritu i baritu područja prače, jugoistočna bosna [sulphur isotopic analyses in galena, chalcopyrite, pyrite and barite of area prače, south-eastern bosnia – in serbian].– institut jože štefan, ljubljana. fond dokumenata instituta. radvanec, m. (1992): zonality of low pressure and polyphase fl uidopen metamorphism in the gneiss-amphibolite complex of gemericum.– mineralia slovaca, 24, 175–196. radvanec, m., grecula, p. & žak, k. (2004): siderite mieralization of the gemericum superunit (western carpathians, slovakia): review and a revised genetic model.– ore geology review, 24, 267–298. ramović, e. (1991): metalogenija bosne i hercegovine [metallogeny of bosnia and herzegovina – in croatian].– unpubl. phd thesis, faculty of mining, geology and petroleum engineering, university of zagreb, 239 p. ramović, m. (1954): izvještaj o geološko-rudarskim radovima tokom 1954. godine na istragama cinka i olova u srezu foča [report of geological and mining activity regarding zinc and lead investigations during 1954 in canton foča – in serbian].– fond stručnih dokumenata, sarajevo, 28 p. ramović, m. (1956): kratki pregled baritnih ležišta bosne i hercegovine [short overview of barite deposits in bosnia and herzegovina– in serbian].– geološki glasnik, 2, 67–82. ramović, m. (1957): pregled nalazišta minerala cinka i olova u bosni i hercegovini [overview of mineral deposits of zinc and lead in bosnia and herzegovina – in serbian].– geološki glasnik, 3, 3–121. ramović, m., gagić, m., đurić, s., knežević, v. & turić, m. (1976): barit [barite – in serbian]. – in: čičić, s. (ed.): mineralne sirovine bosne i hercegovine, prvi tom, knjiga ii, ležišta nemetala, geoinženjering, sarajevo, 358–379. ramović, m., kubat, i., veljković, d., kulenović, e. & đurić, s. (1979): ležišta obojenih metala jugoistočne bosne u okolini prače, foče, goražda i čajniča [deposits of coloured metals of south-eastern bosnia in the surrounding of prača, foča, goražde and čajnice – in serbian].– in: čičić, s. (ed.): mineralne sirovine bosne i hercegovine, drugi tom, knjiga iii, ležišta obojenih metala, geoinženjering, sarajevo. ramovš, a. & kulenović, e. (1982): o novim nalazištima starijeg paleozoika u jugoistočnoj bosni [about new lower palaeozoic localities in south-eastern bosnia – in serbian].– geološki glasnik, 27, 49–60. geologia croatica 63/2geologia croatica 258 ramovš, a., hinterlechner-ravnik, a., kalenić, m. karamata, s., kochansky-devide, v., krstić, b., kulenović, e., mirković, m., petkovski, p., sremac, j. & tenkova, v. (1984): stratigraphic correlation forms (sfc) of yugoslav palaeozoic. igcp no. 5 newsletter 6, 81–109, barcelona. rick, b. (1990): sulphur and oxygen isotopic composition of swiss gipskeuper (upper triassic).– chemical geology, 80/3, 243–250. schneiderhöhn, h. (1942): die erzlagerstättenlehre, 240 p. schroll, e. & pak, e. (1980): schwefelisotopenzusammensetzung von baryten aus den ost–und südalpen. tschermaks min. petr. mitt., 27, 79–91. schulz, o. (1972): unterdevonische baryt–fahlerz–mineralisation und ihre steilachsige verformung im groβkogel bei brixlegg (tirol).– tschermaks min. petr. mitt., 18, 114–128. sephton, m.a., looy, c.v., veefkind, r.j. & al. (2002): synchroneus record of δ13c shifts in the oceans and atmosphere at the end of the permian.– in: koebert, c. & macleod, k.g. (eds.): catastrophic events and mass extinctions: impacts and beyond. geol. soc. of america, sp. paper, 356, 455–462. sofilj, j., živanović, m. & pamić, j. (1980): osnovna geološka karta sfrj 1:100000, tumač za list prozor [basic geological map of sfry 1:100000, geology of the prozor sheet – in serbian].– savezni geološki zavod, beograd, 49 p. strmić, s., palinkaš, l., jurković, i. & hrvatović, h. (2000): the fl uids in quartz from the middle bosnia.– in: vlahović, i. & biondić, r. (eds.): 2th hrvatski geološki kongres – cavtat, svibanj 2000, zbornik radova, institut za geološka istraži vanja, zagreb, 415–419. sun, s.s. & mcdonough, w.f. (1989): chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes.– in: saunders, a.d. & norry, m.j. (eds.): magmatism in the ocean basins, geological society, special publication, london, 42, 313–345. šiftar, d. (1988): the chemical characteristics of barite from some bosnian deposits.– rudarsko-metalurški zbornik, 35, 75–89. šiftar, d. (1990): usporedba kemizma barita iz područja raštelice i kreševa u srednjobosanskom rudogorju [comparison of barite chemistry rom raštelica area and kreševo in mid-bosnian ore mountains – in croatian].– geol. vjesnik, 43, 109–112. šinkovec, b. (1971): geology of iron and copper deposit at rude near samobor.– geol. vjesnik, 24, 165–181. vujnović, l. (1983): osnovna geološka karta sfrj 1:100000, tumač za list prača [basic geological map of sfry 1:100000, geology of the prača sheet – in serbian].– savezni geološki zavod, beograd, 56 p. wallmann, k. (2001): the geological cater cycle and the evolution of marine δ18o values.– geochimica et cosmochimica acta, 65, 2469–85. wopfner, h. (1984): permian deposits of the southern alps as product of initial alpidic tephrogenesis.– geol. rundschau, 73, 259– 277. žak, k., radvanec, m., bartalsky, b. & grecula, p. (1991): sr, s, c, o-isotopes and metamorphic-hydrothermal model of vein mineralisation in the gemericum [in slovakian].– mineralia slovaca, 23, 95–108. živanović, m. (1962): izvještaj o geološkoj prospekciji paleozojskog područja prača–foča [report of geological prospecting of palaeozoic area in prača-foča – in serbian].– fond stručnih dokumenata, geoinstitut, sarajevo, 74 p. živanović, m. (1972): geological structure and tectonic framework of the vranica mountain in central bosnia (in serbian).– unpubl. phd thesis, university of beograd. manuscript received september 19, 2009 revised manuscript accepted april 30, 2010 available online june 28, 2010 geo.cro.2-3-61-kb.pdf 333 � daniela basso1, davor vrsaljko2 and tonći grgasović3 ab stra ct the fossil coralline fl ora of the badenian bioclastic limestone outcropping in northern croatia is known by the name “litavac”, shortened from “lithothamnium limestone”. the name was given to indicate that unidentifi ed coralline algae are the major component. in this fi rst contribution to the knowledge of the coralline fl ora of the litavac, lithothamnion valens seems to be the most common species, with an unattached, branched growth-form. small rhodoliths composed of phymatolithon calcareum and mesophyllum roveretoi also occur. the badenian benthic association is dominated by melobesioid corallines, thus it can be compared with the modern maërl facies of the atlantic ocean and mediterranean sea. since l. valens still survives in the present-day mediterranean, an analogy between the badenian litavac and the living l. valens facies of the mediterranean is suggested. keywor ds: calcareous rhodophyta, corallinales, rhodoliths, maërl, badenian, croatia 1 dipartamento di scienze geologiche e geotecnologie, università degli studi di milano – bicocca, piazza della scienza 4, 20126 milano, italy; (daniela.basso@unimib.it) 2 croatian natural history museum, demetrova 1, hr-10000 zagreb, croatia; (davor.vrsaljko@hpm.hr) 3 croatian geological survey, sachsova 2, hr-10000 zagreb, croatia; (tgrgasovic@hgi-cgs.hr) the coralline fl ora of a miocene maërl: the croatian “litavac” geologia croatica 61/2–3 333–340 1 fig. 1 pl. zagreb 2008 geologia croaticageologia croatica � 1. introduction since roman times, a building stone named “litavac” has been quarried at many croatian localities, particularly on the sw slopes of the medvednica mts. (fig. 1). the name derives from the shortening of the croatian words litotamnijski vapnenac meaning “lithothamnium limestone”. the litavac corresponds to a facies of biolithites and bioclastic limestones (e.g. biocalcirudites, biocalcarenites and biocalclutites) belonging to the upper badenian succession (lower serravallian of the standard chronostratigraphy; details in piller et al., 2007) which are characterized by fully marine environments in northern croatia (kochanski, 1944; šikić, 1967, 1968; avanić et al., 1993; vrsaljko et al., 2005, 2006). the upper badenian deposits unconformably overlie older rocks, and in the area of mt. medvednica over upper triassic dolomites. the litavac facies is interposed between a facies of coarse-grained clastics (with clasts from underlying dolomites and limestones), at the base and an overlying facies of fi ne-graded clastics: fi ne-graded sands, marls, clayey limestones and calcsiltites (vrsaljko et al., 2006, 2007a). litavac is almost structureless, but cross-bedding or even fl at-bedding can occasionally be observed. a description of the stratigraphy and palaeogeography of miocene deposits from the investigated area (sw medvednica) and neighbouring samoborsko gorje – žumberak mts. is provided by vrsaljko et al. (2005). the sedimentology and palaeoenvironmental evolution of upper badenian and sarmatian deposits of mt. medvednica is discussed by vrsaljko et al. (2006). the litavac is composed predominantly of corallines with fragments of bivalves including lucinoma boreale (l.), nucula sp., pectinidae, ostrea sp., arcidae, glycymerididae, cardiidae, glossus humanus (l.), corbula gibba (olivi), gastropods (conus sp. ficus sp.), echinoderms (clypeaster sp.), marine benthic foraminifers (textulariidae, planostegina sp., amphistegina sp., brizalina dilatata (reuss), heterolepa dutemplei (d’orbigny) with common lobatula lobatula geologia croatica geologia croatica 61/2–3 334 (walker & jacob), elphidium fi chtelianum (d’or bigny) and rare planktonic forams), ostracods (i.e. cytheretta tenuipunctata dentata brestenska), bryozoans, hydrozoans and corals (flabellum sp.), denoting a shelf palaeoenvironment within the infralittoral to shallow circalittoral zones (vrsaljko et al., 2007a, c,d). the skeletal fragments are cemented with calcite. the name “lithothamnium limestones” refers to the dominance of coralline nodules and remains but has simply a lithogenetic sense, since several genera of non-geniculate coralline algae other than lithothamnion can be identifi ed. the same is true for the tortonian “calcari a briozoi e litotamni” of the central-southern apennines in italy, (= bryozoan and lithothamnium limestones; simone & carannante, 1985; brandano, 2002), for the badenian leitha limestone of the vienna basin (=nullipora, lithothamnium or lithothamnion limestone; riegl & piller & 2000), for the badenian leithakalk units of hungary (randazzo et al., 1999) and for the early badenian pinczow limestones in poland (studencki, 1988). despite the historical use of litavac as a building stone (more than 2250 m3 were used to build the present zagreb cathedral; vrsaljko & al., 2007a,b), and its importance as a reservoir rock for water and oil and gas (lučić et al., 2001), the taxonomy of the coralline algae composing the limestone has never been investigated in detail. the aim of this paper is to provide a fi rst account of the fossil coralline fl ora of the northern croatian litavac, and its possible palaeoenvironmental interpretation. 2. material and methods sampling has been performed at the quarries of gornje vrapče and bizek (nw of zagreb, medvednica mt.; fig. 1), in the bioclastic limestones facies of upper badenian age. figured specimens are from the bizek quarry where the litavac crops out and is about 30 m thick (see vrsaljko et al., 2007d). observations of coralline anatomy and biometry have been made on thin sections. thallus nomenclature follows basso et al., (1997). in particular, the terms cortex and medulla, in the description of protuberances, are used with a merely topographic sense, to distinguish the central cell fi laments running parallel to the main axis of the protuberance (= the medulla) from the derivatives diverging and bending toward the surface of a protuberance (= the cortex). the terms unattached branches and prâline are used according to basso (1998). growthform nomenclature follows woelkerling et al., (1993). percentage quantifi cation of total coralline algal thalli is based on visual estimate. 3. results the litavac from the studied localities is a calcareous rudstone, mainly composed of fragments of fruticose corallines (vrsaljko et al., 2007d, fi g. 2). the litavac corallines are free-living, unattached branches or small rhodoliths with various degrees of protuberance development. the litavac underwent dolomitization and dissolution, preventing identifi cation of a large part of the algal remains. however, despite fi gu re 1: map of the investigated litavac quarries in the zagreb area, croatia. geologia croaticadaniela basso et al.: the coralline fl ora of a miocene maërl: the croatian “litavac” 335 fossil diagenesis, numerous algal fragments still have their microscopical anatomy preserved, therefore allowing identifi cation. 3.1. the coralline fl ora division rhodophyta wettstein, 1901 order corallinales silva & johansen, 1968 family hapalidiaceae gray, 1864 emend. harvey, broadwater, woelkerling & mitrovski, 2003 subfamily melobesioideae bizzozero, 1885 genus phymatolithon foslie, 1898 phymatolithon calcareum (pallas) adey & mckibbin, 1970 (pl. 1, fig. 1) neotype: bm box collection no. 1626 (woelkerling & irvine, 1986). basionym: millepora calcarea pallas 1766, p.265. 1943 pomatophyllum operculatum conti, p. 52–54, fi g. 3, pl. vi/4, pl. viii/5 1950 lithothamnion operculatum conti, p. 117 1997 phymatolithon calcareum – basso et al., p. 168–170, pl. 36 the lumpy growth-form of this species has been identifi ed in a single rhodolith, about 6 mm in diameter, among dominant branches of l. valens. the thallus shows a thin hypothallium, with cells l 6–11 x d 6–7 μm, a perithallium with cells l 8–11 x d 7–8 μm and rounded multiporate conceptacles with diam. 125–150 x 75–90 μm in height. although the epithallial cells are not preserved, the specimen is attributed to phymatolithon calcareum on the basis of the correspondence of all the other known anatomical features (basso et al., 1997). p. calcareum is distributed from the oligocene to recent (basso et al., 1997). genus mesophyllum lemoine, 1928 mesophyllum roveretoi conti, 1943 (pl. 1, figs. 2–3) protologue: conti, 1943, p.55, pl. vii, fi g. 1a–c; pl. 8, fi g. 6. rhodolith-forming plant with a lumpy growth-form shows stout protuberances reaching about 2 mm in length. each thallus barely exceeds 450 μm in thickness, but several thalli are superimposed to give the total thickness. in thin sections, the protuberances appear to have originated from the superposition of fertile and sterile layers of the thallus, which thicken up in correspondence with the conceptacle chambers. hypothallium coaxial is 100–200 μm thick, with cells l 22–25 x d 12–14 μm. perithallial cells are l 9–16 x d 8–9 μm. multiporate conceptacles abundant has d 275–425 x h 155–205 μm with roof thickness of 50–75 μm. several conceptacle chambers show a partial infi ll of irregularly-shaped, large “cells”. the stratigraphic distribution of m. roveretoi ranges from the upper eocene to the miocene of the tertiary piedmont basin (fravega et al., 1987) and in the badenian of the leitha limestone (vienna basin; conti, 1946b). genus lithothamnion heidrich, 1897 lithothamnion valens foslie, 1909 (pl. 1, figs. 4–6) holotype: trh, unnumbered; includes slides 1731–1733. fig ur ed by basso et al. (1997, pl. 37, fi gs. 1–8; pl. 38, fi gs. 3, 5, 6). 1946a lithothamnium ramosissimum (gümbel non reuss) conti, p.18–22, pl. i/1 a–f; pl. vii/1–3 1997 lithothamnion valens – basso et al. (1997), p. 170– 176 the species is common as branches and their fragments, with diameters ranging from 2 to 4–5 mm. also some prâlines with fruticose growth-forms have been identifi ed. single protuberances (branches) can regularly exceed 2 cm in length. fragments of branches containing the hypothallium have not been observed. the perithallium shows a sharp zonation, with large rectangular cells (l 17–24 x 9–12 μm) at the base of each growth zone, gradually decreasing in size toward the more square shaped cells at the top of the same zone (l 10–12 x 9–12 μm). this superimposed growth zone begins sharply with the large cells, without any transition. multiporate conceptacle chambers d 260–380 x h 105–120 μm show roof thickness ranging from 32 to 45 μm. the stratigraphic distribution of l. valens ranges from the priabonian to the recent (basso et al., 1997). 3.2. the facies on the basis of the lithology and fossil components (relative abundance of prâlines, more or less fragmented coralline unattached branches, small and large benthic/planktic foraminifera and molluscan remains) at least three different facies can be distinguished within the bizek limestone. branches dominate in facies a, small rhodoliths dominate in facies b, corallines are fragmented and probably were not autochthonous in facies c. facies a and b were also recognized at gornje vrapče (fig. 1), though their geometry and palaeoenvironmental / stratigraphic relationships need further investigation. facies a (pl. 1, fig. 7) has been sampled at about 50 cm above the triassic base. it represents a micro-breccia with angular and sub-rounded clasts of dolomite mixed with bioclasts. coralline branches and their fragments are dominant in the limestone. other components include centimetre to millimetre-sized fragments of bryozoan colonies and small benthic foraminifera (lobatula lobatula, textularidae, elphidiidae, miliolidae). external moulds of large arcidae and glycymeris sp. randomly occur. dolomitization of bioclasts is extensive, and was followed by dissolution, both of bioclasts and lithoclasts. the resulting mouldic porosity involves about 20–30% of the rock. the well preserved algal fragments (about 20–40% of the total algal fragments) are irregularly cylindrical, 1–5 mm in diameter and up to about 1 cm in length. corallines with lumpy to fruticose growth-forms compose sparse, small prâlines (sensu basso, 1998), 1–3 cm in diameter. most algal remains belong to l. valens, with the contribution of p. calcareum and m. roveretoi. geologia croatica geologia croatica 61/2–3 336 plate 1 1 phymatolithon calcareum (pallas) adey & mckibbin, 1970. two conceptacles with the characteristic roof. note thallus zonation and abraded thallus surface. thin section biz1, bizek quarry, om photograph. 2 mesophyllum roveretoi conti, 1943. several superimposed fertile thalli which compose a protuberance. the coaxial hypothallium is visible. thin section cro4/1c, bizek quarry, om photograph. 3 mesophyllum roveretoi conti, 1943. detail of the multiporate conceptacles. the improper thallus orientation hides the coaxial organization of the hypothallium. thin section cro4/1c, bizek quarry, om photograph. 4 lithothamnion valens foslie, 1909. an oblique section of a protuberance showing the typical thallus zonation and multiporate conceptacles. note diagenetic fractures deforming the original conceptacle shape. thin section cro4/1a, bizek quarry, om photograph. 5 lithothamnion valens foslie, 1909. a longitudinal section of a protuberance showing the sharp zonation in the medulla and the multiporate conceptacles developing in the. cortex. thin section biz6, bizek quarry, om photograph. 6 lithothamnion valens foslie, 1909. detail of the multiporate conceptacles of fig. 5. note the preservation of some (?sporangial) remains hanging from the roof of the conceptacle. thin section biz1, bizek quarry, om photograph. 7 litavac facies a (bizek quarry, sample biz 1). note the preserved fossil algal thalli appearing as white, irregular cylindrical clasts in the limestone (thick arrows on branching growth-forms). mouldic porosity due to dissolution of dolomitic clasts is indicated by thin arrows. 8 litavac facies b (bizek quarry, sample biz 6). note the common occurrence of small rhodoliths (thick arrows), together with branching growth-forms and the abundant larger foraminifera (arrows). 9 litavac facies c (bizek quarry, sample biz 8). most coralline algae that occur as micro-fragments are detectable only under o.m. benthic and planktic foraminifera are the major components. note also common ditrupa (thick arrows) and molluscan (arrow) shell fragments. geologia croaticadaniela basso et al.: the coralline fl ora of a miocene maërl: the croatian “litavac” 337 geologia croatica geologia croatica 61/2–3 338 two other facies b and c (pl. 1, figs. 8, 9) appear as lateral variations at the same stratigraphic level, at about 15 m height within the upper badenian strata. in the algal biocalcarenite of facies b (pl. 1, fig. 8), which represents the most typical litavac, the fragments of coralline branches become less abundant and smaller, while small rhodoliths become common. the coralline fl ora is composed of lithothamnion spp. and mesophyllum spp. large benthic foraminifera (amphistegina and planostegina) are the co-dominant components. in facies c (pl. 1, fig. 9), an evident orientation of the grains is observed. it represents a mud supported micro-conglomerate with small sub-rounded dolomitic clasts in a matrix of fi ne grained crushed bioclasts. the dominant components are the large benthic foraminifera, mostly as fragments, together with small benthic and common planktic foraminifera. other components are small gastropods and fragments of bivalves together with annelid tubes. millimetre-sized fragments of uncommon corallines also occur. 4. discussion and conclusions the accumulation of prevalently loose-lying non-geniculate, branched corallines corresponds to the modern concept of maërl. maërl is a breton word defi ning a benthic association dominated by free-living, branching algal thalli. along the north-western coast of france, at many localities in ireland, and in galicia, maërl covers large areas of the infralittoral seafl oor at < 20 m of water depth in a macrotidal environment, thus exposed to oscillating tidal currents (cabioch, 1969; biomaerl team, 2003). in the mediterranean, maërl occurs infrequently at about 40 m of water depth, in current-swept, coastal bio-detritic, benthic environments of the upper circalittoral zone (basso & brusoni, 2004). the available literature reports analogues of fossil algal facies in the miocene of europe. the “branching algae facies” reported by studencki (1988) occurs in the basal layer of the pinczow limestone outcropping west of pinczow (ne of cracow, poland). it is composed of an accumulation of branching thalli of sporolithon sp. and lithothamnion valens (reported as archaeolithothamnium sp. and lithothamnium ramosissimum (gümbel) respectively in studencki, 1988) and subordinate encrusting growth-forms of mesophyllum ingestum conti, 1946b and neogoniolithon contii (mastrorilli) quaranta, vannucci & basso, 2007 (reported as mesophyllum rigidum mastrorilli in studencki, 1988). this facies has been interpreted as the fi rst step of an ecological succession leading to a rhodolith pavement along a shallowing trend (studencki, 1988). maërl occurs as a facies of the leitha limestone in the vienna basin (dullo, 1983; riegl & piller, 2000). several species of non geniculate corallines have been identifi ed in the austrian leitha limestone, among which the most common are lithothamnion valens, lithothamnion ramosissimum (reuss) piller, 1994, phymatolithon calcareum, mesophyllum roveretoi, spongites albanensis (lemoine) braga, bosence & steneck, 1993 (for reference: conti, 1946b; piller, 1994; basso et al., 1997). among these species, l. valens and l. ramosissimum commonly show a free-living, branching growth-form, while the others have been identifi ed as encrusting thalli or rhodolith builders. a cool-water, algal rudstone/fl oatstone microfacies composed of whole and fragmented red algae has been described for the hungarian leithakalk (randazzo et al., 1999). corallines appear in numerous growth-forms, can be referred to maerl or prâlines and are associated with benthic foraminifera (amphistegina and heterostegina) and worm tubes. they are reported to belong to several coralline genera, including lithothamnion, sporolithon (quoted as archaeolithothamnion), meso phyllum and lithophyllum. unluckily, the absence of palaeontological descriptions and insuffi cient illustration prevent confi rmation and more detailed identifi cation of the reported taxa (randazzo et al., 1999). branch fragments of corallines in a marly matrix, possibly comparable with a maërl, occur in the badenian algal limeston es of the transylvania basin (romania; bucur & fili pes cu, 1994). the diversifi ed coralline fl ora of the badenian algal limestones includes several species of the genera sporolithon, lithothamnion (among which l. ramosissimum, quoted as p. archaeotypum conti), mesophyllum (among which m. roveretoi), lithophyllum and spongites albanensis (quoted as lithophyllum?albanense lemoine), mostly composing rhodoliths (bucur & filipescu, 1994). these observations support the conclusion that in paratethys, a badenian maërl was predominantly composed of lithothamnion (free-living branches) and mesophyllum, with locally subordinate sporolithon, spongites and phymatolithon (in rhodoliths). we can attempt a comparison of this badenian fossil association with the present-day maërl. the coralline association of the atlantic maërl (nw france, ireland and galicia) is dominated by lithothamnion corallioides (p.l. & h.m. crouan) p.l. & h.m. crouan, 1867 and phymatolithon calcareum. other species contributing to the atlantic maërl are lithothamnion glaciale kjellman, lithothamnion tophiforme (esp er) unger, 1858, lithophyllum dentatum (kützing) foslie, 1900, lithophyllum fasciculatum (lamarck) foslie, 1900 and, more occasionally, mesophyllum. the mediterranean maërl has a diversifi ed algal fl ora, with the occurrence of several species of lithothamnion, phymatolithon, lithophyllum and mastophoroideae. presently, l. valens is a mediterranean endemic, infrequently occurring at considerable depth (50–70 m), mainly in the western mediterranean (basso, 1996; babbini & bressan, 1997). in the tropics, an analogous maërl (based on the algal growthform) is represented by the accumulation of unattached branches of neogoniolithon in seagrass meadows (basso et al., in press). the badenian maërl has no obvious analogies with the tropical neogoniolithon facies. the atlantic and the mediterranean maërl and their badenian fossil counterparts are dominated by melobesioid corallines. however, one of the most characteristic and abundant species in the badenian maërl, lithothamnion valens, does not occur in the present-day maërl association living in the atlantic. since l. valens still occurs in relatively deep mediterranean waters, we conclude that the geologia croaticadaniela basso et al.: the coralline fl ora of a miocene maërl: the croatian “litavac” 339 temperate-water, modern mediterranean maërl is fl oristically the most similar analogue of the badenian litavac. however, direct palaeodepth interpretations based on the mediterranean occurrence of l. valens would be speculative, until further palaeoecological investigations based on the whole benthic association and sedimentary environment of the litavac have hopefully clarifi ed the matter. references adey, w.h. & mckibbin, d. (1970): a revision of the foslie crustose coralline herbarium. – k. norske videns. selsk. skr., 1, 1–46. avanić, r., kovačić, m., pavelić, d., miknić, m., vrsaljko, d., bakrač, k. & galović, i. (2003): the middle and upper miocene facies of mt. medvednica (northern croatia). – in: vlahović, i. & tišljar, j. (eds.): stages in evolution of the miocene north croatian basin (pannonian basin system). 22nd ias meeting of sedimentology, field trip guidebook, 167–172. babbini, l. & bressan, g. (1997): recensement des corallinacées de la mer méditerranée et considérations phytogéographiques. – bibliotheca phycologica, 103, 421 p. basso, d. (1996): soft bottom mediterranean calcareous algae (nongeniculate corallinaceae): distribution and ecology. – in: albertelli, g., de maio, a. & piccazzo, m. (eds.): atti dell’11 congresso a.i.o.l., sorrento, 26–28 ottobre 1994, 225–234. basso, d. (1998): deep rhodolith distribution in the pontian islands, italy: a model for the paleoecology of a temperate sea. – paleo. paleo. paleo., 137, 173–187. basso, d. & brusoni, f. (2004): the molluscan assemblage of a transitional environment: the mediterranean maërl from off the elba island (tuscan archipelago, tyrrhenian sea). – boll. malacol., 40, 37–45. basso, d., fravega p. & vannucci, g. (1997): the taxonomy of lithothamnion ramosissimum (gümbel non reuss) conti and lithothamnion operculatum (conti) conti (rhodophyta, corallinaceae). – facies, 37, 167–182. basso, d., nalin, r. & nelson, c.s. (in press): shallow water sporolithon rhodoliths from north island (new zealand). – palaios. biomaerl team (2003): conservation and management of northeast atlantic and mediterranean maërl beds. – aquatic conservation: marine and freshwater ecosystems, 13/1, s65–s76. braga, j.c., bosence, d.w.j. & steneck, r.s. (1993): new anatomical characters in fossil coralline algae and their taxonomic implications. – palaeontology, 36, 535–547. brandano, m. (2002): la formazione dei “calcari a briozoi e litotamni” nell’area di tagliacozzo (appennino centrale) e considerazioni paleoambientali sulle facies rodalgali. – boll. soc. geol. it., 121, 179–186. bucur, i.i. & filipescu, s. (1994): middle miocene red algae from the transylvanian basin (romania). – beitr. paläont., 19, 39–47. cabioch, j. (1969): les fonds de maërl de la baie de morlaix et leur peuplement végétal. – cahiers de biologie marine, 10, 139–161. conti, s. (1943): contributo allo studio delle corallinacee del terziario italiano. ii: le corallinacee del miocene del bacino ligure-piemontese. – palaeont. ital., 41, 37–61. conti, s. (1946a): revisione critica di lithothamnion ramosissimum reuss. – pubbl. ist. geol. univ. genova, serie a, 1, 3–29. conti, s. (1946b): le corallinaceae del calcare miocenico (leithakalk) del bacino di vienna. – pubbl. ist. geol. univ. genova, serie a, 2, 31–68. conti, s. (1950): alghe corallinaceae fossili. – pubblicazioni dell’istituto di geologia dell’universita di genova 4 (ser a), 1–155. crouan, p.l. & crouan, h.m. (1867): florule du finistère. – friedrich klincksieck & j.b. et a. lefournier. dullo, w.c., (1983): fossildiagenese im miozänen leitha-kalk der paratethys von österreich: ein beispiel für faunenverschiebung durch diageneseunterschiede. – facies, 8, 1–112. foslie, m. (1900): new or critical calcareous algae. – kongelige norske videnskabers selskabs skrifter, 5, 1–34. foslie, m. (1909): algologische notiser. vi. – k. norske vidensk. selsk. skr., 2, 1–63. fravega, p., giammarino, s., piazza, m., russo, a. & vannucci, g. (1987): signifi cato paleoecologico degli episodi coralgali a nord di sassello. nuovi dati per una ricostruzione paleogeografi co-evolutiva del margine meridionale del bacino terziario del piemonte. – atti soc. tosc. sc. nat. mem, s. a, 94, 19–76. kochanski, v. (1944): fauna marinskog miocena južnog pobočja medvednice (zagrebačke gore) (miozäne marine fauna des südlichen abhanges der medvednica – zagreber gebirge). – vjestnik hrvatskog drž. geol. zavoda i hrv. drž. geol. muz., 2–3, 171–280. lučić, d., saftić, b., krizmanić, k., prelogović, e., britvić, v., mesić, i. & tadej, j. (2001): the neogene evolution and hydrocarbon potential of the pannonian basin in croatia. – marine and petroleum geology, 18, 133–147. pallas, p.s. (1766): elenchus zoophytorum sistens generum adumbrationes generaliores et specierum cognitarum succinctas descriptiones cum selectis auctorum synomymis. – p. van cleef, hague, 265, 28+451 p. piller, w.e. (1994): nullipora ramosissima reuss, 1847 – a rediscovery. – beitr. paläont., 19, 181–189. piller, w.e., harzhauser, m. & mandić, o. (2007): miocene central paratethys stratigraphy – current status and future directions. – stratigraphy, 4, 151–168. quaranta, f., vannucci, g. & basso, d. (2007): neogoniolithon contii comb. nov. based on the taxonomic re-assessment of mastrorilli’s original collections from the oligocene of nw italy (tertiary piedmont basin). – riv. ital. paleont. strat., 113, 43–55. randazzo, a.f., müller, p., lelkes, g., juhász, e. & ham-or, t. (1999): cool-water limestones of the pannonian basinal system, middle miocene, hungary. – j. sed. res., 69, 283–293. riegl, b. & piller, w.e. (2000): biostromal coral facies – a miocene example from the leitha limestone (austria) and its actualistic interpretation. – palaios, 15, 399–413. šikić, l. (1967): torton i sarmat jugozapadnog dijela medvednice na osnovi faune foraminifera (torton und sarmat des südwestlichen teils der medvednica auf grund der foraminiferenfauna). – geol. vjesnik, 20, 127–135. šikić, l. (1968): stratigrafi ja miocena sjeveroistočnog dijela medvednice na osnovu faune foraminifera (über di miozänstratigraphie des nordöstlichen teiles des medvednica gebirges auf grund der foraminifferenfaunen). – geološki vjesnik, 21, 213–227. simone, l. & carannante, g. (1985): evolution of a miocene carbonate open shelf from interception to drowning: the case of the southern apennines. – rend. acc. sci. fis. mat., iv, lii/2, 1–43. studencki, w. (1988): facies and sedimentary environment of the pinczow limestones (middle miocene; holy cross mountains, central poland). – facies, 18, 1–26. unger, f. (1858): beiträge zur näheren kenntniss des leithakalkes, namentlich der vegetabilischen einschlüsse und der bildungsgeschichte desselben. – denkschr. kais. akad. wiss., math.-nat. klasse, 14, 13–35. geologia croatica geologia croatica 61/2–3 340 vrsaljko, d., pavelić, d. & bajraktarević, z. (2005): stratigraphy and palaeogeography of miocene deposits from the marginal area of žumberak mt. and the samoborsko gorje mts. (northwestern croatia). – geol. croat., 58/2, 133–150. vrsaljko, d., pavelić, d., miknić, m., brkić, m., kovačić, m., hećimović, i., hajek-tadesse, v., avanić, r. & kurtanjek, n. (2006): middle miocene (upper badeninan/sarmatian) palaeoecology and evolution of the environments in the area of medvednica mt. (north croatia). – geol. croat., 59/1, 51–63. vrsaljko, d., hećimović, i. & avanić, r. (2007a): miocene deposits of northern croatia. – in: grgasović, t. & vlahović, i. (eds.): 9th international symposium on fossil algae, field trip guidebook and abstracts. croatian geological survey, zagreb, 143– 153. vrsaljko, d., marković, s. & grgasović t. (2007b): zagreb cathedral of the assumption of the blessed virgin mary. – in: grgasović, t. & vlahović, i. (eds.): 9th international symposium on fossil algae, field trip guidebook and abstracts. croatian geological survey, zagreb, 155. vrsaljko, d., miknić, m., hajek-tadesse, v., bakrač, k., avanić, r., grizelj, a. & koch, g. (2007c): miocene deposits in gornje vrapče. – in: grgasović, t. & vlahović, i. (eds.): 9th international symposium on fossil algae, field trip guidebook and abstracts. croatian geological survey, zagreb, 161–163. vrsaljko, d., avanić, r., miknić, m., grizelj, a., hajektadesse, v. & bakrač, k. (2007d): the badenian deposits of bizek quarry. – in: grgasović, t. & vlahović, i. (eds.): 9th international symposium on fossil algae, field trip guidebook and abstracts. croatian geological survey, zagreb, 165–167. woelkerling, w.j. & irvine, l.m. (1986): the typifi cation and status of phymatolithon (corallinaceae, rhodophyta). – british phycol. j., 21, 55–80. woelkerling, w.j., irvine, l.m. & harvey, a.s. (1993): growth -forms in non-geniculate coralline red algae. – austral. syst. bot., 6, 277–293. manuscript received may 25, 2008 revised manuscript accepted july 31, 2008 goldscheider.indd 137 � ab stra ct mobile particles play crucial roles for contaminant transport in karst aquifers, but few studies have investigated the relationships between sediment dynamics and contaminants. this is partly due to the diffi culty in monitoring suspended particles: turbidity is easy to measure but does not deliver detailed information on the size and type of particles; mineralogical laboratory analyses are laborious and not suitable for continuous monitoring. a portable particle counter was used for the study presented here. the instrument delivers time-series of particle-size distribution (psd), i.e. the number and diameter of suspended particles, grouped into different size-classes ranging from 0.9 to 139 µm. the test site is a karst system near the city of yverdon-les-bains, switzerland. a swallow hole draining agricultural land is connected to two karst springs, 4.8 and 6.3 km away, which are occasionally contaminated by faecal bacteria at highly variable levels. turbidity alone turned out not to be a reliable indicator for microbial contamination. to obtain more insight into bacteria and particle transport towards the springs, a comprehensive research program was carried out, including tracer tests and monitoring of psd, turbidity, total organic carbon (toc), faecal bacteria (e. coli) and various hydrologic and physicochemical parameters. results show that there are two types of turbidity: a primary turbidity signal occurs shortly after rainfall during the rising limb of the hydrograph; a secondary signal typically occurs during spring fl ow recession. the fi rst signal is explained by remobilization of conduit sediments due to a hydraulic pressure pulse (autochthonous or pulse-through turbidity). the second peak indicates the arrival of water from the swallow hole, often together with toc and faecal bacteria (allochthonous or fl ow-through turbidity). psd analyses revealed that autochthonous turbidity is composed of a broad mixture of fi ne and large particles, while allochthonous turbidity predominantly consists of very fi ne particles. this is explained by sedimentation of larger particles between the swallow hole and the springs. during allochthonous turbidity periods, very good correlation between the fi nest particles (0.9–1.5 µm) and e. coli was found (r2 = 0.93). the relative increase of fi ne particles can consequently be used as an “early-warning parameter” for microbial contamination of karst spring water. further applicability and limitations of this approach are also discussed. keywords: particle-size distribution, turbidity, faecal bacteria contamination, karst groundwater monitoring, total organic carbon new insights into the transport of sediments and microorganisms in karst groundwater by continuous monitoring of particle-size distribution � nico goldscheider1, michiel pronk2 and jakob zopfi 3 1 technische universität münchen (tum), department for civil, geoand environmental engineering, hydrogeology and geothermics group, arcisstr. 21, 80333 munich, germany; (goldscheider@tum.de) 2 centre of hydrogeology, university of neuchâtel, 2009 neuchâtel, switzerland; (michiel.pronk@unine.ch) 3 institute of geology and paleontology, university of lausanne, 1015 lausanne, switzerland; (jakob.zopfi @unil.ch) doi: 104154/gc.2010.10 geologia croatica 63/2 137–142 5 figs. zagreb 2010 geologia croaticageologia croatica geologia croatica 63/2geologia croatica 138 2. test site and methods 2.1. test site the studied karst aquifer system is located near the city of yverdon-les-bains, switzerland, between two major geological and landscape units: the folded jura mountains and the molasse basin, forming the swiss plateau (fig. 1). the se slope of the jura mountains, where upper jurassic (malm) and cretaceous limestones outcrop, is the principal autogenic recharge area of the aquifer system. further to the se, due to a complex arrangement of folds and faults, limestone is exposed in two “hydrogeologic windows” within the low-permeability sediments of the swiss plateau. at the western window, a stream sinks into the feurtille swallow hole at an altitude of 600 m. the stream drains agricultural land and frequently contains high levels of turbidity, toc and faecal bacteria. about 4 km to the east, at the second window (mont de chamblon), two springs are located at approximately 450 m: the moulinet spring, which consists of eight orifi ces showing identical physicochemical characteristics, and the cossaux spring, which is captured by eight inclined drillings and contributes to the water supply of the city. five tracer tests have been carried out during different hydrological conditions, ranging from low-fl ow to high-fl ow, in order to characterize the connection between the swallow hole and the springs. transit times (fi rst tracer detection) varied between 24 hours during very high-fl ow conditions and 12 days during extreme low-fl ow conditions. this also means that suspended particles and associated contaminants infi ltrating into the swallow hole are expected to arrive at the springs after about 1 to 12 days, depending on the hydrological conditions. this discovery makes it easier to interpret the variability of natural parameters monitored at the springs, as described below. fi gu re 1: geologic map of the karst system near yverdon-les-bains. the feurtille swallow hole (f) is connected to two karst springs: moulinet (m) and cossaux (c). reprinted with permission from pronk et al. (2007). copyright 2007 american chemical society. 1. introduction sediments in karst conduits and suspended mineral particles in groundwater are crucial for the transport and attenuation of contaminants in karst aquifers, such as toxic metals, dnapls and pathogenic microorganisms. however, relatively few studies have investigated sediment dynamics and sedimentcontaminant interactions in karst groundwater fl ow systems (mahler & lynch, 1999, mahler et al., 2000, vesper & white, 2003, vesper & white, 2004). a major challenge lies in the monitoring of suspended particles in groundwater and spring water. two conventional techniques are commonly used – turbidity measurements and mineralogical laboratory analyses of water samples. both approaches have advantages but also major drawbacks: turbidity is an optical parameter qualitatively indicating the amount of colloids and particles in the water; it can easily be measured continuously, but turbidity measurements do not deliver any detailed and quantitative information concerning the size, number and type of suspended particles (massei et al., 2006, schnegg, 2002). mineralogical and geochemical analyses in the laboratory can deliver this type of information but are laborious and consequently not suitable for continuous monitoring (herman et al., 2007). therefore, a modern portable particle counter was used for the study presented here. the instrument delivers quasicontinuous time-series of particle-size distribution (psd), i.e. the number and size of suspended particles in water. the test site is a karst aquifer system in western switzerland, consisting of a swallow hole draining agricultural land, connected to two karst springs, one of which is used as a drinking water source for the city of yverdon-les-bains. occasional faecal bacteria contamination at highly variable levels poses a problem for the water supplier. turbidity alone turned out not to be a reliable indicator for water quality – contamination sometimes occurred when turbidity was low, while high values did not always correspond to poor water quality. therefore, the main objectives of this study were: • to better understand the origin, transport and dynamics of suspended sediment particles and faecal bacteria in karst groundwater fl ow systems; • to test the applicability and limitations of particle counters and continuous psd monitoring for karst hydrogeological studies; and • to identify reliable “early-warning parameters” indicating the possible presence of faecal and pathogenic microorganisms in karst spring water. major results of this study, which also included detailed microbiological investigations using methods from molecular microbiology and unsaturated zone investigations, have been published in several papers by the authors (pronk et al., 2006, 2007, 2009a, b). this communication focuses on the application and usefulness of psd measurements for the monitoring of microbial water quality for the springs of yverdon-les-bains. goldscheider et al.: new insights into the transport of sediments and microorganisms in karst groundwater... geologia croatica 139 particle (fig. 2). this makes it possible to count the particles and measure their equivalent spherical diameters. 3. results and discussion 3.1. spring response to an individual rainfall event two types of turbidity were observed at the springs during and after storm rainfall (fig. 3). a primary turbidity signal (t1) occurred during the rising limb of the spring hydrograph, explained by the remobilization of sediments from karst conduits due to a hydraulic pressure pulse; it is thus referred to as autochthonous or pulse-through turbidity. a secondary turbidity signal (t2) occurred 1 to 12 days later and is explained by the arrival of turbid storm-derived water 2.2. monitoring of physicochemical and microbiological parameters discharge, water temperature (t), electrical conductivity (ec), total organic carbon (toc) and turbidity were monitored continuously at the swallow hole and the two springs using weirs and pressure probes (dl/n 64, sts, sirnach, switzerland), ec-t probes (cond 340i, wtw, weilheim, germany), data loggers (dt50, datataker, rowville, australia) and fi eld fl uorometers (ggun-fl30, neuchâtel, switzerland). daily precipitation data (meteoswiss) from three stations were considered. during selected hydrological events, water samples were collected hourly using automatic samplers (6712c sampler, teledyne isco, lincoln, usa) with sterilized bottles, transported to the laboratory in cooling boxes, and processed with in 6 h to 30 h for chemical and microbiological analyses. samples were analyzed for major inorganic ion chemistry using ion chromatography (ic dx-120, dionex, sunnyvale, usa) and for faecal indicator bacteria, mainly e. coli, using standard cultivation techniques. 2.3. monitoring of particle-size distribution particle-size distribution (psd) was monitored at the springs during selected high-fl ow events using a portable particle counter (abakus mobil fl uid, klotz, unterhaugstett, germany) that counts suspended particles in the range of 0.9 to 139 µm and groups them into up to 32 defi nable size classes. the instrument takes discrete measurements in suffi ciently short (minutes), defi nable time intervals, to be used for quasi-continuous monitoring. the measurement principle is as follows: the water sample, usually 10 ml, passes through a fi ne tube (0.3 mm) illuminated by a laser beam perpendicular to its axis. a light detector measures the intensity decline caused by the individual particles, i.e. the “shadow” of each fi gu re 2: schematic illustration of the particle counter. the water sample passes through a tube illuminated by a laser beam. every particle (1, 2, 3) creates a “shadow” observed at a light detector, which makes it possible to determine the number and size of the particles. fi gu re 3: variability of discharge, turbidity, toc and two diff erent particle-size classes at the moulinet spring. the primary turbidity signal (t1) consists of a mixture of fi ne and large particles; the secondary signal (t2) is mainly composed of fi ne particles (0.9–1.5 µm) and high toc levels. geologia croatica 63/2geologia croatica 140 that entered the swallow hole; it is thus referred to as allochthonous or fl ow-through turbidity. this range of transit times and its dependency on the hydrological conditions coincide well to the transit times obtained by tracer tests. during the fi rst turbidity signal, toc remains constant and low at prestorm levels, while the second turbidity signal coincides with a signifi cant increase of toc. as toc typically originates from the soil, land surface and sinking streams, this observation supports the allochthonous origin of the second turbidity signal. psd monitoring allowed further differentiation of the two turbidity signals. while the primary turbidity signal (t1) consists of a broad mixture of fi ne and larger particles, the secondary turbidity (t2) signal is predominantly composed of very fi ne particles (colloids) with an equivalent spherical diameter of 0.9–1.5 µm. the explanation can be found in the classical hjulström diagram, which describes the relations between fl ow velocity and erosion, transport and deposition of sediment particles of different size. increased fl ow velocities during the rising limb of the spring hydrograph mobilize a mixture of clay and silt particles, but only the very fi ne particles are transported from the swallow hole to the spring, while larger particles are removed by sedimentation. 3.2. spring response to a double rainfall event fig. 4 presents monitoring results from the moulinet spring following two successive intense precipitation events. two primary, autochthonous turbidity signals (t1a, t1b) were observed shortly after the two rainfalls, when spring discharge was rapidly increasing. these signals consist of a mixture of fi ne and larger particles and are characterised by stable and very low levels of e. coli and toc. two secondfi gu re 4: variability of psd, e. coli and various hydrological and physicochemical parameters at the moulinet spring following a double rainfall event. (a) feurtille swallow hole and (b) moulinet spring. adapted with permission from pronk et al. (2007). copyright 2007 american chemical society. a) b) goldscheider et al.: new insights into the transport of sediments and microorganisms in karst groundwater... geologia croatica 141 ary, allochthonous turbidity signals (t2a, t2b) occurred several days later and are mainly composed of very fi ne particles (0.9–1.5 µm). toc increases in two steps and e. coli display two distinct peaks, highly correlated to the evolution of fi ne particles (r2 = 0.93). these fi ndings clearly indicate the arriv al of storm-derived water from the swallow hole, containing high levels of toc and faecal bacteria. most large particles have been removed by sedimentation between the swallow hole and the springs, attenuation processes. 4. conclusions and outlook turbidity in karst groundwater has two principal origins: autochthonous turbidity results from the mobilization or remobilization of sediments in karst conduits, while allochthonous turbidity originates from the soil zone, land surface or sinking surface streams (fig. 5). monitoring of particle-size distribution (psd) makes it possible to characterise and differentiate the two turbidity types. autochthonous turbidity consists of a broad mixture of different particle-size classes. in the allochthonous turbidity, most large particles have been removed by sedimentation in the system, so that this turbidity is predominantly composed of fi ne particles. toc and faecal bacteria also originate from the land surface or sinking streams, i.e. they are also allochthonous (fig. 5). therefore, the differentiation of autochthonous and allochthonous turbidity has practical implications for spring water quality monitoring. two alternative “early-warning systems” for the possible presence of faecal bacteria and pathogenic microorganisms can be proposed: • the simultaneous increase of turbidity and toc; • the selective increase of fi ne particles (0.9–1.5 µm) without signifi cant variation of larger particles. monitoring of various high-fl ow events at the yverdonles-bains test site, at another karst aquifer system in the jura mountains, and at an unsaturated zone experimental site (pronk et al., 2009b), demonstrated that these early-warning systems are reliable in the case of microbial contamination resulting from agricultural activities at the land surface. such contamination enters the aquifer during rainfall and recharge periods, while direct and permanent wastewater injections into sinking streams, or into groundwater, are likely to cause permanent spring water contamination without distinct toc or psd variations. besides the practical use for water-quality monitoring, psd measurements can also aid the acquisition of better insights into other relevant processes in karst systems, such as soil erosion and the removal of residual clay and silt during karstifi cation and speleogenesis. acknowledgment we thank the water supply company of yverdon-les-bains for technical and logistic support, and the swiss national science foundation (grant no. 200020-113609/1) for funding. references goldscheider, n. & drew, d. (2007): methods in karst hydrogeology iah: international contributions to hydrogeology, 26.– taylor & francis, london, 264 p. herman, e.k., tancredi, j.h., toran, l. & white, w.b. (2007): mineralogy of suspended sediment in three karst springs.– hydrogeology journal, 15/2, 255–266. mahler, b.j. & lynch, f.l. (1999): muddy waters: temporal variation in sediment discharging from a karst spring.– journal of hydrology, 214/1–4, 165–178. mahler, b.j., personne, j.c., lods g.f. & drogue c. (2000): transport of free and particulate-associated bacteria in karst.– journal of hydrology, 238/3–4, 179–193. massei, n., dupont, j.p., mahler, b.j., laignel, b., fournier, m., valdes, d. & ogier, s. (2006): investigating transport properties and turbidity dynamics of a karst aquifer using correlation, spectral, and wavelet analyses.– journal of hydrology 329/1–2, 244–257. pronk, m., goldscheider, n. & zopfi, j. (2006): dynamics and interaction of organic carbon, turbidity and bacteria in a karst aquifer system.– hydrogeology journal, 14/4, 473–484. pronk, m., goldscheider, n. & zopfi, j. (2007): particle-size distribution as indicator for fecal bacteria contamination of drinking water from karst springs.– environmental science & technology 41/24, 8400–8405. pronk, m., goldscheider, n. & zopfi, j. (2009a): microbial communities in karst groundwater and their potential use for biomonitoring.– hydrogeology journal, 17/1, 37–48. pronk, m., goldscheider, n., zopfi, j. & zwahlen, f. (2009b): percolation and particle transport in the unsaturated zone of a karst aquifer.– ground water, 47/3, 361–369. fi gu re 5: block diagram of a karst aquifer illustrating diff erent origins of sediment particles and faecal bacteria in spring water. particles either originate from remobilization of intrakarstic sediments (autochthonous) or from the soil and sinking streams, often including high levels of bacteria and organic carbon (allochthonous) (modified after goldscheider & drew, 2007). geologia croatica 63/2geologia croatica 142 schnegg, p.a. (2002): an inexpensive fi eld fl uorometer for hydrogeological tracer tests with three tracers and turbidity measurement; xxxii iah and alhsud congress groundwater & human development. balkema, mar del plata, argentina, 1484–1488. vesper, d.j. & white, w.b. (2003): metal transport to karst springs during storm fl ow: an example from fort campbell, ky/tn, usa.– journal of hydrology, 276/1–4, 20–36. vesper, d.j. & white, w.b. (2004): spring and conduit sediments as storage reservoirs for heavy metals in karst aquifers.– environmental geology, 45/4, 481–493. manuscript received november 24, 2009 revised manuscript accepted march 19, 2010 available online may 31, 2010 geo.cro.2-3-61-kb.pdf 73 � robert riding ab stra ct authigenic seafl oor carbonate crusts include fenestrate microbialite, thrombolite, and four types here designated: fine-grained crust, sparry crust, hybrid sparry fine-grained crust, and sparry crust plus coarse grains. each of the latter four types includes at least some layered examples that have generally been regarded as stromatolites. recognition and interpretation of these various deposits assists understanding of stromatolite development. sparry crust is common in the late archaean-mesoproterozoic. it includes botryoidal fans and other crystal pseudomorphs, microdigitate stromatolite, dendrite, isopachous laminite, and herringbone calcite. although differing in primary mineralogy and bedform, these are all characterized by coarse sparry, commonly radial fi brous, fabric and appear light coloured in thin-section. they have commonly been referred to as seafl oor cement, although they formed at the open sediment-water interface rather than as void-fi lls. two of them in particular, isopachous laminite and microdigitate “tufa”, typically form isopachous layers with good vertical inheritance and have been regarded as stromatolites. in contrast to sparry crust, fine-grained crust has fi ne-grained (micritic, clotted, peloidal, fi lamentous) microfabric that appears dark in thin-section, and irregular uneven layering with relatively poor inheritance. mixed crusts, composed of millimetric alternations of sparry and fine-grained crust, are here termed hybrid sparry finegrained crust. sparry crust with coarse allochthonous grains – here termed sparry crust plus coarse grains – includes some examples that have been given formal stromatolite names, e.g., gongylina and omachtenia. sparry, hybrid, and fine-grained crusts are common components of precambrian stromatolites. their relative abundances change through time. archaean stromatolite fabrics are commonly obscured by recrystallization, but their preserved lamina arrangements suggest that many of them could be composed mainly of sparry or hybrid crust. during the palaeoproterozoic-mesoproterozoic, sparry crust fabrics were common in peritidal stromatolites, whereas hybrid crust appears to have dominated large subtidal domes and columns. fine-grained crust may not have become generally abundant until the neoproterozoic, when it commonly formed both stromatolites and throm bolites. phanerozoic normal marine stromatolites are also typically composed of fine-grained crust. present-day analogues of sparry crust fabrics occur in some speleothem, hot spring, and splash-zone marine crusts, and of fine-grained crust in lithifi ed microbial mats. light-dark millimetric alternations of sparry and fi ne-grained crust that characterize hybrid crust have analogues in freshwater stromatolites. taken together, these com parisons suggest that some precambrian stromatolites are abiogenic, some microbial, and others are intimate hybrid mixtures of the two, and that – preservation permitting – these varieties can be distinguished using microfabric and lamina criteria. keywor ds: archaean, carbonate, microbial, proterozoic, stromatolite, thrombolite department of earth and planetary sciences, university of tennessee, 1412 circle drive, knoxville, tn 37996, usa; (riding@cardiff.ac.uk) abiogenic, microbial and hybrid authigenic carbonate crusts: components of precambrian stromatolites geologia croatica 61/2–3 73–103 14 figs. 1 tab. zagreb 2008 geologia croaticageologia croatica � geologia croatica geologia croatica 61/2–3 74 1. introduction stromatolites (kalkowsky, 1908) are often carbonate in composition and characteristically exhibit decimetric domical and columnar morphologies (hofmann, 1969). based on present-day analogues (walcott, 1914; black, 1933; logan 1961), they have long been regarded essentially as lithifi ed microbial mats (awramik & margulis, 1974). however, morphological similarities between stromatolites and a variety of other geological deposits and structures have confused their recognition and generated debate about how the term “stromatolite” should be defi ned (semikhatov et al., 1979; riding, 1999; awramik & grey, 2005). uncertainty about kalkowsky’s (1908) view of stromatolites has been created by a defi nition made by krumbein (1983, p. 499) and wrongly attributed to kalkowsky: “stromatolites are organogenic, laminated, calcareous rock structures, the origin of which is clearly related to microscopic life, which in itself must not be fossilised”. although kalkowsky (1908) did not write this statement (see riding, 1999, p. 323), it has been repeated as if it were a literal translation from his paper (e.g., ginsburg, 1991, p. 25; feldmann & mckenzie, 1998, p. 201; grotzinger & knoll, 1999, p. 316; mcloughlin et al., 2008, p. 96). compounding this mistake, the somewhat awkward wording employed by krumbein (1983) (use of “must not” rather than “need not”) has been cited not only as “paradoxical”, and “confusion” to be avoided, but also as an example of the defi ciencies of such genetic defi nitions (grotzinger & knoll, 1999, p. 316; mcloughlin et al., 2008, p. 96). in his 1908 paper ernst kalkowsky did not provide a specifi c defi nition of stromatolite, apart from repeatedly emphasizing that they he regarded them as laminated organic structures. he thought that the life forms involved were “niedrig organisierte planzliche organismen” (simple plantlike organisms, kalkowsky, 1908, p. 125). it is reasonable to conclude that he regarded stromatolites essentially as laminated microbial deposits (riding, 1999). during the century since kalkowsky (1908) introduced the term “stromatolith” (stromatolite), particular problems have centred on confi dent discrimination between lithifi ed microbial mats and a variety of other geological deposits that can have broadly similar appearances, such as invertebrate skeletons, diagenetic concretions, deformation structures, and sub-aqueous abiogenic precipitates. the variety of these diffi culties has been reduced as understanding of fossils and carbonate sediments has progressed. for example, it is now unusual for invertebrate skeletons or diagenetic concretions to be mistaken for lithifi ed microbial mats, although confusion between deformed soft sediment and microbial domes was suggested relatively recently (lowe, 1994). however, research (e.g., grotzinger 1989a, b) incrementally focused attention on the diffi culty of discriminating between lithifi ed microbial mats and sparry sub-aqueous authigenic carbonate crusts. this continuing problem (perry et al., 2007) can arise for several reasons. firstly, essentially abiogenic seafl oor crusts and lithifi ed mic robial mats can both create layered, often domical, structures of broadly similar appearance. second ly, processes that drive seafl oor precipitation and microbial calcifi cation are not necessarily mutually exclusive, and their products may be intimately associated, raising the possibility that, in addition to lithifi ed microbial mat and sparry crust end -members, there are deposits that represent complex mixtures of both. thirdly, scarcity of present-day analogues for sparry seafl oor crusts (grotzinger & james, 2000, p. 9) has hindered their recognition as distinct deposits. the need to distinguish these components has been recently emphasized. perry et al. (2007, p. 169) noted that “microbially constructed stromatolites should not … be confused with abiotic, chemically precipitated carbonate crusts”. pope et al. (2000, p. 1139) regarded “iso pachous stromatolites to have been dominated by chemogenic precipitation in the absence of microbial mats, and the growth of peloidal stromatolites to have been controlled by sedi mentation in the presence of microbial mats”, and suggested that “thinly laminated isopachous stromatolites are considered to have a largely abiotic origin” (idem, p. 1149). here i explore this suggestion that microfabric details and lamina arrangement can be used to discriminate between an cient abiogenic deposits and those made by microbial mats, by reviewing published details of precambrian authigenic carbonate crusts and their possible present-day analogues. in addition to stromatolites, precambrian authigenic subaq ue ous carbonate crusts include botryoidal crystal fans, dendrite, herringbone calcite, fenestrate microbialite, and thrombolite. since these are often intimately associated with stromatolites and share similar components with them, i include them here. but the focus is stromatolites, and three generalizations arise from this overview. firstly, precambrian stromatolites basically consist of one or both of two com ponents: fi ne-grained carbonate and sparry carbonate. secondly, com parisons with present-day analogues suggest that finegrained crust is lithifi ed microbial mat, and that sparry crust is essen tially abiogenic. thirdly, precambrian stromatolites generally consist of one of these components (fine-grained crust, spar ry crust) or of millimetric alternations of both of them – hybrid crust. tracing the secular distribution of these deposits reveals that hybrid crusts were very important in stromatolite formation during the palaeoproterozoic and meso proterozoic. they are major components of large stromatolite domes that dominate subtidal facies of extensive proterozoic carbonate platforms such as the ~1.9 ga pethei group (sami & james, 1996) and ~1.0 ga burovaya formation (petrov & semi khatov, 2001, fi g. 6). the combination of microbial growth and abiogenic precipitation in hybrid crusts may have promot ed rapid accretion of these large, locally decametric, stroma tolites. some archaean stromatolites are equally large, e.g., in the campbellrand-malmani platform of south africa (beuk es, 1987) and at steep rock, ontario (wilks & nisbet, 1985). these examples are more diffi cult to interpret because discrimination between sparry and fine-grained crust relies on microfabric details that are readily obscured by poor preservation in old stromatolites. in the campbellrand, large elongate stromatolite domes that are mageologia croaticarobert riding: abiogenic, microbial and hybrid authigenic carbonate crusts: components of precambrian stromatolites 75 jor components of extensive platform carbonates (sumner & grotzinger, 2004, fi gs. 2,10) have an overall appearance of smooth even lamination penetrated by crystal pseudomorphs (sumner & grotzinger, 2004, fi g. 11a) consistent with essentially abiogenic precipitation. however, these “boetsap laminae” contain both sparry and micro crystalline layers, and the latter could be interpreted as detrital silt or as microbial mat pre cipitate (sumner & grotz inger, 2004, fi g. 3). if the micro crystalline layers are silt that was not microbially trap ped, and the sparry fabrics are abiogenic crusts, then these large domes would be essentially abiogenic structures; but if they are mat precipitate then these deposits are hybrid crusts. discrimination between sparry and hybrid crusts therefore focuses attention on whether such large archaean domes are hybrid combinations of mats and abio genic crusts, similar to those of the pethei and burovaya reefs, or are sparry crusts – possibly with detrital carbonate – and therefore essentially abiogenic? proterozoic stromatolite devel opment is more readily interpreted due to better overall preservation. hybrid crust dominated subtidal stromatolites during the early-mid proterozoic, and sparry crust pro gressively declined (grotz inger & kasting, 1993, p. 235; kah & knoll, 1996, p. 81). by the neoproterozoic, fine-grained crust stromatolites (and thrombolites) had probably surpassed hybrid crust de posits in abundance. this suggests that, whereas present-day microbial mats may provide analogues for most phane rozoic stromatolites, their relevance is diminished in examples older than ~1000 ma. these considerations lead to a liberal view of the term “stromatolite” as broadly encompassing laminated authigenic crusts formed at the sediment-water interface in springs, rivers, lakes and seas. these characteristically can exhibit both large and small domical and columnar morphologies. 2. precambrian carbonate crusts research into precambrian stromatolites has revealed not only fi ne-grained lithifi ed microbial mats (e.g., vologdin, 1962; walter, 1972; komar, 1976) but also dis tinct ive sparry fabrics. radial spar is the dominant component of the small digitate stromatolites recognized by donaldson (1963) and described as microdigitate tufa by hoffman (1975). these were given names such as pseudogymnosolen (cao & liang, 1974) and asperia (semikhatov, 1978) and came to be generally termed microdigitate stromatolites. larg er stromatolites often exhibit sparry layers that alternate with fi ner ones (hofmann, 1969, p. 4, 16, fi g. 13), as in conophyton (komar et al., 1965) (fig. 1) and in botryoidal sparry crust fabrics of digitate stromatolites that bertrandsar fati (1972) compared with calcifi ed cyanobacterial co lonies. at the same time, evidence of early lithifi cation was noticed in the localization of stromatolitic carbonates (serybryakov & semikhatov, 1974), and in the support re quired by high-relief coniform stromatolites (gebelein, 1976; donaldson, 1976). john grotzinger’s research, beginning with the ~1.9 ga rocknest platform, was seminal in focusing attention on these seafl oor precipitates. recognition of the primary aragonite mine ra logy of microdigitate stromatolites (grotzinger & read, 1983) led to interpretation of large crystal botryoids as originally aragonite rather than gypsum, and to the sug gesti on that long-term decline in deposits such as microdigitate stromatolites could refl ect progressive reduction in seawater carbonate saturation (grotzinger, 1989a, p. 96, fi g. 15). grot zinger (1989b, p. 11) listed “substrate-parallel layers of neomorphic fi brous cement”, “radial fi brous fabics … that constitute microdigitate stromatolites”, and “conoform stro ma tolites” as evidence for “in situ carbonate production”. the outcome was increased recognition of seafl oor sparry crusts. the superposed radial fi brous botryoid fabrics of meso proterozoic tarioufetia and tungussia, fi rst thought to be cal cifi ed cyanobacteria (bertrand-sarfati, 1972), were com pared with aragonite cements (fairchild et al., 1990, p. 61). in addition to botryoidal fans and microdigitate stro matolites, isopachous laminite (jackson, 1989), den drites (sami & james, 1996, fi g. 6a), and herringbone calcite (grotzinger & kasting, 1993), were distinguished, especially in palaeoproterozoic and archaean carbonates. as a result, grotzinger & james (2000, p. 7) were able to sum marize precambrian marine “abiotic precipitates” as: (i) decimetric to metric radial fans (after aragonite), (ii) mic rodigitate stromatolites, (iii) isopachous millimetric la minites, (iv) isopachous layers of herringbone calcite, and (v) dendrites (“dendritic tufa”). grotzinger & knoll (1999, p. 329– 330) cited “petrographic evidence not only for early lithi fi cation, but also for direct growth of encrusting marine cement directly on the growing stromatolite, particularly for stro matolites of mesoproterozoic and older ages”. fi gu re 1: conophyton. stag arrow formation, manganese group, bangemall basin, western australia, ~1050–1100 ma. width of view, 5.5cm. photograph courtesy of kath grey. geologia croatica geologia croatica 61/2–3 76 sparry crusts occur thinly interlayered with fi ne-grained crust in coniform stromatolites (e.g., walter, 1972), and, for example, in palaeoproterozoic pethei stromatolites described by sami & james (1996), in latest mesoproterozoic and early neoproterozoic baicalia lacera described by knoll & semikhatov (1998) and petrov & semikhatov (2001), and in the ~800 little dal “lamelliform elements” described by aitken (1989) and turner et al. (2000a). thus, the main components of precambrian subaqueous carbonate crusts recognized here are sparry and fi ne-grained precipitates, and hybrid mixtures of the two. all three of these may incorporate allochthonous grains. discrimination of mudand silt-grade allochthonous grains is diffi cult, but coarse grains can be recognized. these components occur in fi ve main combinations (fig. 2): fine-grained crust, sparry crust, hybrid sparry fine-grained crust, sparry crust with coarse grains, and fine-grained crust with coarse grains. all of these include at least some deposits that have been generally regarded as stromatolites. fine-grained crust with coarse grains is common in neogene coarse-grained stromatolites, such as lee stocking island and some shark bay columns, but does not appear to be common in the precambrian. two additional seafl oor crust categories that are locally common during certain periods in the precambrian, but which do not contain stromatolites, are fenestrate microbialite and throm bolite. accordingly, the categories of seafl oor carbonate crust discussed here include fine-grained crust, sparry crust, hybrid sparry fine-grained crust, sparry crust with coarse grains, fenestrate microbialite and thrombolite (table 1). these are outlined below. fi gu re 2: authigenic sparry and fi ne-grained carbonate crust recognized here together with hybrid crust and coarse-grained admixtures. all crust categories in boxes (fine-grained, sparry, hybrid, sparry + coarse grains, and fine-grained + coarse grains) all include at least some deposits that have been generally regarded as stromatolites. note that fi ne-grained crust can include fi ne allochthonous grains as well as fi ne-grained in situ precipitate. table 1: categories of subaqueous authigenic carbonate crust common in precambrian carbonates. fine-grained crust, sparry crust, hybrid sparry fine-grained crust and sparry crust with coarse grains all contain examples generally regarded as stromatolites. the following general interpretations, based on present-day analogues, are suggested: finegrained crust, fenestrate microbialite and thrombolite represent lithifi ed microbial mat; sparry crust and sparry crust with coarse grains are essentially abiogenic precipitates. hybrid sparry fine-grained crust results from submillimetric to millimetric alternations of sparry (abiogenic) and fine-grained (lithifi ed microbial mat) crust. 1. fine-grained crust 2. sparry crust botryoidal fans and crystal pseudomorphs; radial fi brous microbotryoids microdigitate stromatolite; dendrite isopachous laminite herringbone calcite 3. hybrid sparry fine-grained crust microcrystalline-peloidal carbonate conophyton baicalia lacera laminar fi brous crusts and micritic peloidal laminae clotted-bushy-peloidal micrite filamentous boetsap laminae: microspar crusts of uncertain origin 4. sparry crust plus grains herringbone calcite with coarse grains radial fi brous crust with silt and sand grains (e.g., gongylina, omachtenia) crystal fans with coarse grains 5. fenestrate microbialite 6. thrombolite geologia croaticarobert riding: abiogenic, microbial and hybrid authigenic carbonate crusts: components of precambrian stromatolites 77 2.1. fine-grained crust fine-grained (micritic, clotted, peloidal, fi lamentous) microfabrics and irregular uneven layering with relatively poor inheritance are typical of microbial stromatolites (e.g., monty, 1976). these fabrics occur interleaved with other deposits in hybrid crusts, but on their own they also constitute the dominant components of many stromatolitic domes, columns and layers, as well as thrombolites. they may contain fenestrae and incorporate allochthonous grains. in older examples the micritic fabrics have often aggraded to microspar. finegra ined subaqueous crust described here is regarded as the pro duct of lithifi ed microbial mats, and therefore as an es sentially biotic deposit (see present-day analogues). proterozoic fine-grained crust, together with including hybrid crust, is fi gured extensively by vologdin (1962). latest ediacaran examples are fi gured by schmitt (1979, pl. 16, fi gs. 3, 4; pl. 22, fi g. 2) from the anti-atlas mountains, morocco. neoproterozoic examples (some of which are fenestral) with “streaky” microstructure occur in the ~800 ma bitter springs formation of central australia (walter, 1972, pls. 2, 3, 23, 25) and in the little dal reefs (e.g., turner et al., 2000a, fi g. 15f). in the little dal, these locally also exhibit fi lamentous fabrics (e.g., aitken, 1989, fi g. 10; turn er et al., 2000a, fi g. 8 e, f, g). jefferson & young (1989, fi g. 5a) show stromatolites underlying the little dal group which have “clotted/grumous microfabric”. grotzinger & knoll (1999, fi g. 3f) fi gure fi lament moulds in “micritic stromatolite laminae” from the neoproterozoic chernya rechka formation, siberia. riding & sharma (1998) found clotted microfabrics “irregular masses of micrite bounded by microspar and sparite” to be the common in late palaeoproterozoic vempalle stromatolites from southern india. in riding & sharma (1998), they dominate ex am ples of both poorly (idem, fi g. 2) and evenly (idem, fi gs. 3, 4) laminated forms in which sparry layers or fenestrae occupy a relatively minor volume of the structure. in general, however, fi ne-grained stromatolites – as opposed to hybrid crusts – appear relatively scarce in the palaeo pro terozoic, but this requires further verifi cation. 2.2. sparry crust sparry crust includes stromatolitic deposits (microdigitate stromatolite, isopachous laminite); large and small botryoidal fans as well as related crystal pseudomorphs; extensive her ringbone calcite beds; and rarely recorded large den dri tes. 2.2.1. botryoidal fans and crystal pseudomorphs these centimetric to metric pseudomorphs after crystals that formed at the sediment-water interface occur as layers and beds, commonly draped by fi ne-grained carbonate. typically they are conical and fan-shaped with a convex upper surface (fig. 3). they range from isolated skeletal crystals and widely spaced “fanning pseudomorphs” to extensive beds of juxtaposed botryoids of upwardly diverging radial crystal fans, e.g., in the late archaean campbellrand-malmani platform of south africa (sumner & grotzinger, 2000, fi gs. 3a, 5; sumner & grotzinger, 2004, fi g. 7). the original mineralogy of these “giant botryoids” (grotz inger & kasting, 1993, p. 234) has been interpreted as gypsum (bertrand-sarfati, 1976; hardie, 2003) or aragonite (sumner & grotzinger, 1996a, p. 120). they also occur in the ~3.45 ga warrawoona group ~50 km west of marble bar, western australia (hofmann et al., 1999, p. 1257); the ~2.8 ga steep rock carbonate platform, ontario; the ~2.6 ga carawine dolomite, western australia; the ~2.9 ga uchi greenstone belt of ontario (sumner & grotzinger, 2000, p. 139), and as “coxco needle” fans in the ~1.64 ga mcarthur group of the northern territory, australia (winefield, 2000). at steep rock they may form the structure that walcott (1912) named atikokania (hof mann, 1971; sumner & grotz inger, 2000, p. 134). fans up to 1.6m high that lack detrital sediment fi gu re 3: laterally juxtaposed botryoidal radial fans with convex internal bands. late archaean campbellrand-malmani platform, south africa. width of fi eld ~12 cm. geologia croatica geologia croatica 61/2–3 78 indicate they “did not grow within the sediment” (sumner, 2002, p. 109). sumner & grotz ing er (2000, p. 139) regarded “all the pseudomorphs as replacing aragonite with the exception of morphologically distinct gypsum pseudomorphs from the 2.6 ga carawine dolomite (simonson et al., 1993)” (sum ner, 2002, p. 109). bertrand-sarfati (1976) interpreted camp bellrand-malmai crystal rosettes as pseudomorphs after gypsum. martin et al. (1980) considered similar “radiating crystal structures” associated with stromatolitic domes, in the ~2.6 ga cheshire formation of the belingwe greenstone belt, ~150 km east of bulawayo, zimbabwe, to be replacements of aragonite or gypsum. grotzinger & kasting (1993, p. 235) cited “prolifi c precipitation of aragonite as giant botryoids up to 1 m in radius” as evidence that archaean seawater was signifi cantly oversaturated for caco3. well exposed fan beds occur in the cambellrand-malmani platform (sumner & grotzinger, 1996a, fi g., 4; 2000, fi g. 3). sumner & grotzinger (2000, p. 131–133) described cyclic sequences (approximately similar in age to those described by martin et al., 1980) in huntsman quarry, ~50 km nne of bulawayo with layers of crystal fans after aragonite, herringbone calcite, large domical stromatolites (described by macgregor, 1941), and fenestrate microbialite. they concurred with mac gregor (1941) that the environment was probably subtidal. hardie (2003) restated bertrandsarfati’s (1976) interpretation that late archaean fans were after gypsum. sumner (2004) countered this with petrographic and trace element data that support their primary aragonite mineralogy (see also sumner & grotzinger, 2000, p. 1137–1139). radial fi brous microbotryoids. small (~< 1 mm) radial fi brous botryoids, reminiscent of far larger “giant” botryoids (e.g., grotzinger & kasting, 1993), form tussocky microfabric in some mesoproterozoic stromatolites (bertrand-sarfati, 1976). similar but more irregular “fi brous precipitate masses” are principal components of some pala eoproterozoic stromatolites (sami & james, 1996, fi g. 7c, d). tussocky microstructure (“microstructure en touffes”) occurs as superposed radial fi brous botryoid fabrics in digitate mesoproterozoic stromatolites such as tarioufetia hemi spherica, tungussia globulosa, tungussia cumata and serizia radians in nw africa (bertrand-sarfati, 1972, p. 94, 103, 105, 131, fi g. 26c, pls. 23–26). the columns are elongate to irregular and up to 8cm in diameter and 30 cm in height. the botryoids are sub-millimetric to millimetric and arranged from isolated irregularly superposed hemispheroids to laterally amalgamated layers of lenses. locally botryoids are interlayered with micrite (idem, pl. 25, fi g. 2) and scattered detrital quartz grains (idem, pl. 26, fi g. 1). bert rand-sarfati (1976, p. 253, fi g. 2a) refi gured t. globulosa and described “micro struc ture en touffes” as “tussocks” commonly interlayered by spa rite cement, a dark fi lm, or detrital quartz. she compared them with present-day calcifi ed colonies of rivularia, but it was sub sequently noted that they are “strikingly similar to … originally aragonitic cements” (fairchild et al., 1990, p. 63). in these atar examples intercalated micrite and quartz layers appear to be minor components and so they are here classed as essentially sparry rather than hybrid crust. but in the pethei group, where they also create digitate columnar stromatolites, fi brous precipitate masses are associated with clotted micrite cores and voids fi lled by detrital micrite (sami & james, 1996, fi gs. 7c, d, 8h) and they can be regarded as hybrid crust. sami & james (1996, p. 218) noted that “digitate stromatolite heads composed of clustered fi brous cement fans formed a rigid framework analogous to paleozoic reef fabrics”. 2.2.2. microdigitate stromatolites and dendrite microdigitate stromatolites are small stubby digitate laminated columns, typically <5 mm wide and <20 mm high, closely packed in extensive layered sheets that can dominate the shallow parts of peritidal cycles (hoffman, 1975, p. 262), especially in the early-mid proterozoic (fig. 4). the laminae show good inheritance and may be traced through adjacent columns, and individual columns can exhibit radial fi brous fabric (hofmann & jackson, 1987, p. 964). in the ~2.1 ga denault formation of labrador, donaldson (1963, p. 12, pls. 4–5) noticed very small “digitate stromatolites”, “branching, fi nger-like structures 1 to 5 mm in fi gu re 4: microdigitate stromatolites, silicifi ed after carbonate. wumishan formation, mesoproterozoic, ~25 km north of beijing. width of view ~25 cm. note welldeveloped overall layering, and large size variation of individual digitate forms. geologia croaticarobert riding: abiogenic, microbial and hybrid authigenic carbonate crusts: components of precambrian stromatolites 79 diameter and less than 2 cm in height” that show regular layering and “correspondence of lamination thickness at coincident levels”. hoffman (1975, p. 262) recognized that similar deposits were important components of the shallow parts of rocknest peritidal cycles and described them as “tiny arborescent stromatolites that resemble structures in modern algal tufa. where silicifi ed, microscopic fi lament molds are preserved in the stromatolites”. he compared them with “crusts of calcareous tufa” in “brackish algal marshes, such as those in the bahamas” described by shinn et al. (1969). grotzinger & read (1983, p. 712, fi g. 1f) subsequently termed these rocknest deposits “cryptalgal tufas”, describing them as “cement laminae” that “commonly form discrete, tiny columnar structures (microdigitate stromatolites), 1–10 mm wide and with 0.1–5 mm relief”. they followed hoffman (1975) in interpreting them as tidal fl at deposits but suggested that the environment was semiarid rather than humid, adding “cement crusts appear to have formed by precipitation of aragonite as sheet-like tufa layers and microdigitate stromatolites within mats on surfaces of tidal fl ats or shallow, evaporitic ponds” (grotzinger & read, 1983, p. 712). “digitate stromatolites”, “calcareous tufa” and “cryp talgal tufas” noted by donaldson (1963), hoffman (1975), and grotzinger & read (1983) have also since then variously been termed microdigitate tufa, microdigitate stromatolites, ministromatolites (hofmann & jackson, 1987), and tidal fl at tufa (grotzinger & knoll, 1999, fi g. 4a), as well as being assigned formal names (e.g., pseudo gymnosolen cao & liang, 1974; asperia semikhatov, 1978). grey & thorne (1985) regarded them as biogenic, but grotzinger (1986a, p. 842) considered that “the tufas are, in essence, evaporites”, and suggested that they refl ect “microbially infl uenced inorganic calcifi cation (although it is possible that they are entirely abiotic in origin)” (grotz ing er, 1986b). hofmann & jackson (1987) compared 1.9 ga examples from the belcher supergroup in hudson bay with those described by donaldson (1963) from the de nault formation, and discussed a variety of possible inter pre tations. they compared the radial fi brous fabric with “che mo genic carbonate crusts” including pisoids, aragonite ce ments and speleothems (idem, p. 969) and concluded “chemical pre ci pitation played a signifi cant role in the formation of the ra dial-fi brous fabric here described. whether the precipitation was biologically mediated, or occurred within or on microbial mats is less clear” (idem, p. 970). grotz inger (1989b, p. 11) described them as “microbial tufa”, but subsequently they have often been regarded as inorganic. sami & james (1994, p. 116) described them as cement laminae up to 2 cm thick con sisting of micro digitate “stalks” separated by thinner mi crite layers, and grotz inger & knoll (1999, p. 347) wrote that mic rodigitate stromatolites are “pure precipitate structures”. microdigitate stromatolites are common in late archaean and early proterozoic carbonates (raaben, 1980, 2005; liang et al., 1984, 1985; grey & thorne, 1985, p. 193– 194, fi g. 12; cao, 1991; sharma & shukla, 1998), and are also well-known in the mesoproterozoic (raaben, 1980; kah & knoll, 1996). dendrite. closely spaced subvertical dendrites, often 3– 5 cm in height and ~0.5 cm wide, form layers and irregular higher-than-wide mounds 50 cm or more in width that constitute beds up to ~3m thick; individual dendrites consist of micritic stalks and branches coated by fi brous spar (pope & grotzinger, 2000, p.106, fi g. 5). these dendrites broadly resemble microdigitate stromatolites, but are larger and less well bedded. the hearne formation at the top of the pethei group remains the only described occurrence. they may have fi rst been fi gured by sami & james (1996, fi g. 6a), and are shown as “dendritically branching tufa” by grotzinger & knoll (1999, fi g. 6c; see also grotzinger & james, 2000, fi g. 5e). pope & grotzinger (2000, p. 106–110) described them in detail. they considered the dendrites to be “chemically precipitated structures” formed “in a manner similar to laboratory deposition of zinc and copper dendrites” (pope & grotzinger, 2000, table 1, p. 109). the dendrites are overlain by irregularly laminated stromatolites and then by isopachous laminites. 2.2.3. isopachous laminite isopachous laminite forms stromatolites composed of even, laterally continuous, radial fi brous layers that grew “normal to the stromatolite surface, regardless of local curvature” (grotzinger & knoll, 1999, fi g. 6a, b; pope & grotzing er, 2000, p. 113) (fig. 5). these stromatolites can form thin (e.g., 3–5 m) but extensive beds (jackson, 1989, p. 70) within shallowing sequences, associated with transition to evaporite conditions (pope et al., 2000, p. 1140). in addition to smooth domical morphologies (e.g., grotzinger & knoll, 1999, fi g. 3a), isopachous laminites can exhibit peaked crests (jackson, 1989, fi gs. 6, 13; sumner & grotzinger, 2004, fi g. 4a) and angular asymmetry (pope et al., 2000, fi gs. 2d, 4, 7a, 9b; pope & grotzinger, 2000, fi g. 8). pope et al. (2000, p. 1142) found that “stromatolites with isopachous fi ne lamination” commonly have “radial fi brous texture”. “isopachous, evenly laminated stromatolites”, described in detail from the uppermost pethei group, consist of dolomicrite and fi ne dolosparite (pope & grotzinger 2000, p. 112–113). in the ~2.6 ga cheshire formation of the belingwe greenstone belt, ~150 km ese of bulawayo, martin et al. (1980, fi gs. 10, 12, p. 348, table 2) recognized “crinkle lamination” “with good inheritance” and synoptic relief up to 10 cm, forming metric beds, which they compared with stratifera?. sumner & grotzinger (2000 p. 128) des cribed these as “crinkly laminite facies” overlying pseudo morph fans and “composed of sub-millimeter to millimeter-thick micro sparitic laminae that have a constant thickness normal to la yering”. jackson (1989, p. 70, fi gs. 6, 13) described “un usual, 5 m thick, ridged or peaked stromatolites” interpreted to form a laterally continuous subtidal bioherm in the 1.89 ga cowles lake reef south of coronation gulf, canada, and added “the laminations show very strong inheritance and have a maximum synoptic relief of about 1 m”. grotzinger (1989b, p. 11) commented that these “show textural evidence for having been produced by in situ carbonate progeologia croatica geologia croatica 61/2–3 80 duction”. grotzinger & knoll (1995, p. 581) noted that “stroma tolites formed by direct precipitation on the sea fl oor are a conspicuous feature of archean and proterozoic carbonates. isopachous sparitic, fi brous and micritic layering, generally devoid of clastic carbonate, is the characteristic microstructure. these structures were fully lithifi ed as they accreted”. turner et al. (2000a, p. 189, fi g. 12g) described “cement -rich stromatolites” from the neoproterozoic little dal of north-west canada that form “a uniform veneer of domal stromatolites” (idem, fi g. 11). they consist of millimetric “cement-rich grumous layers alternating with thin fi lms (ca. 100 µm) of micrite”; “laminae are even and regular, and show a high degree of inheritance” (idem, p. 189). pope et al. (2000) fi gured isopachous thinly laminated stromatolites from the ~2.55 ga malmani fm of the transvaal (idem, fi g. 2d), ~1.9 ga uppermost pethei group (idem, fi g. 4), and late permian zechstein deposits of ne england (idem, fi g. 9). they interpreted these to have formed by carbonate pre cipitation at the sediment-water interface, stimulated by high saturation levels (idem, p. 1149), and concluded, “thinly laminated isopachous stromatolites are considered to have a largely abiotic origin, in that as part of the evaporite sequence, the inorganic process of evaporative seawater concentration was critical for their growth” (pope et al. 2000, p. 1149–1150). nonetheless, sumner & grotzinger (2004, p. 7, fi g. 4a) fi gured the same isopachously laminated stroma tolites of the neo archaean cambellrand-malmani platform and sug gested that they formed by precipitation or trapping within microbial mats. late miocene-pliocene (~6–4 ma) lacustrine furnace creek stromatolites in death valley, cali fornia, have isopachous laminae composed of radiating crystal fans interpreted to be “indicative of predominantly abiotic pre cipitation” (corsetti & storrie-lombardi, 2003, fi g. 1). 2.2.4. herringbone calcite herringbone calcite occurs as void-fi lling cement but also, especially in the late archaean, has formed extensive decimetric to metric massive sheet-like seafl oor crusts. it is characterized by distinctive delicate serrated or crenulated banding formed by light and dark couplets ~<1 mm in thickness (fig. 6), and is thought to be derived from a mg-calcite precursor (sumner & grotzinger, 1996b). herringbone calcite occurs as a cement in palaeozoic reef and stromatactis cavities (e.g., krebs, 1969; lehmann, 1978; mcgovney, 1989; de wet et al., 2004) and has been variously named (sumner & grotzinger, 1996b). grotzinger & kasting (1993, fi g. 1) recognized herringbone calcite beds as a feature of late archaean carbonate sedimentation. in the campbellrand-malmani platform, for example (sumner & grotzinger, 1996b), it is laterally extensive, forming decimetric beds traceable over 140 x 50 km in the deep subtidal transgressive gamohaan formation (sumner & grotzinger, 1996b, p. 420; sumner, 2002, fi g. 2c). it is also closely associated with “plumose micro bialites” and in “grainstone-precipitate” beds (sumner, 1997a, table 1, p. 464, 470), where it can be “repetitively interbedded with clastic carbonate on a centimetre scale” (sumner & grotzinger, 1996b, p. 420). it both fi lls voids and isopachously encrusts seafl oor surfaces (sumner & grotzinger, 1996b, p. 420). gandin & wright (2007, p. 301) interpreted some gamohaan herringbone calcite as a replacement of a precursor sediment “likely to have been a gypsum-mush”, whereas sumner & grotzinger (1996a, b) suggested that herringbone calcite refl ects anoxic conditions with low [fe2+] seawater values that inhibited calcite precipitation. herringbone calcite ~2.6 ga in age occurs in huntsman quarry, ~50 km nne of bulawayo, in decimetric layers associated with crystal fans, domical stro ma tolites, and “fenestrated microbialites” (sumner & grotz inger, 2000, fi g. 9). sumner (2002, fi g. 2b) term ed her ringbone calcite “serrate, fi brous marine cement”. 2.3. hybrid sparry fine-grained crust hybrid crust comprises alternations of light-dark layers. for example, bertrand-sarfati (1972, p. 25–26) noted fi gu re 5: peritidal isopachous laminite composed of fi brous dolomite. society cliff s formation, bylot supergroup, ~1.2 ga, white bay, south of bylot island northern baffi n island. width of view, ~7cm. note 1–2 mm very even layering and good inheritance. photograph courtesy of linda kah. geologia croaticarobert riding: abiogenic, microbial and hybrid authigenic carbonate crusts: components of precambrian stromatolites 81 light-dark couplets (“doublet: couche claire et couche som bre”) in some atar and other african proterozoic stromatolites. these include some members of the crustophycaceae and lopatinellaceae of vologdin (1962, p. 195–226), zonalia and arca microstructures of komar (1989, pl. 3), and sparmicrite couplets of sami & james (1996). the dark layers show a variety of micrite and/or microspar fabrics, including dense, peloidal, bushy, clotted, and/or fi lamentous. the light layers are sparry carbonate, often radial fi brous in form. frequency curves of light and dark layer thickness have been used to routinely compare stromatolites with this microstructure (e.g., komar et al., 1965; bertrand-sarfati, 1972, p. 25–26). in english, this general fabric has variously been termed “ribboned” and “striated” (hofmann, 1969, p. 16, fi g. 13), “streaky” (walter, 1972, p. 12), and “fi lm” (bertrand-sarfati, 1976, p. 253). three main types of hybrid crust are recognized here, based on fi ne-grained dark layer microfabric: microcrystallinepeloidal, clotted-bushy-peloidal, and fi lamentous. in addition, layer defi nition, thickness and evenness vary; typically from thinner (≤ 1 mm), better defi ned and more even, to thicker (≥ 1 mm), less well defi ned and less even. layer defi nition, thickness and evenness appear generally to progressively decrease from microcrystalline-peloidal, through clotted-bushy-peloidal, to fi lamentous fabrics. however, fabric preservation com pli cates recognition of these sub-types, particularly of fi la mentous microfabric. for example, knoll & semi khatov (1998, p. 410) found that fi lmy microstructure in early neoproterozoic baicalia lacera “intergrades with a distinctly fi lamentous microstructure”. in contrast, late meso proterozoic b. lacera shows distinctive micritic fi lms but only “rare ghosts of fi laments” (petrov & semikhatov, 2001, p. 270, fi g. 6). whether well-preserved baicalia lacera consistently exhibits fi lamentous microfabric remains to be determined. the categories and examples distinguished here are based on relatively well-preserved proterozoic exam ples. they require further description, comparison and clarifi cation. 2.3.1. microcrystalline-peloidal carbonate conophyton. laterally persistent, interleaved sub-millimetric to millimetric dark-light layers are common in proterozoic coniform stromatolites (vologdin, 1962, pls. 24–25; ko mar et al., 1965; bertrand-sarfati, 1972, pl. 11(4); walter, 1972, p. 103–112) (figs. 7, 8). the layering ranges from uneven with irregular thicknesses to even and regular. thickness and confi guration of these bands are among the features used to distinguish conophyton species (cloud & semikhatov, 1969, fi g. 2), and komar et al. (1965) re cognized general long term increase in dark relative to light laminae in conophyton through the riphean. it was suggested that dark laminae “represent originally algarich layers” (komar et al., 1965, p. 67), and walter (1972, p. 86) commented that “presumably the pale laminae originally had less organic matter”. some coniform stromatolites show co arse sparry layers whose lateral variation in thickness sug gests that they refl ect recrystallization in addition to their primary character (e.g., vologdin, 1962, pl. 32, fi g. 3, pl. 72, fi g. 1; walter, 1972, pl. 10, fi g. 2). fi gu re 6: herringbone calcite seafl oor crust. neoarchaean, campbellrandmalmani platform, south africa. note delicate sub-millimetric uneven, crenulated layering. fi gu re 7: conophyton garganicum, middle riphean, russia. stratigraphic unit and locality not known; specimen donated to geological survey of canada by m.a. semikhatov. width of view 8 mm. note laterally persistent, relatively even, submillimetric interleaved layering of thin fi ne-grained and light-coloured sparry layers, and good inheritance. photograph courtesy of hans hofmann. geologia croatica geologia croatica 61/2–3 82 inzeria lindina. bertrand-sarfati (1972, p. 155, fi g. 58, pl. 22(2, 3)) described repeated millimetric alternations of dolomicrite-microsparite with dolospar in decimetric stubbily branched inzeria lindina from the late? proterozoic of lindi, zaire (now congo). she suggested that these might include seasonal rhythmicity. baicalia. the bands are often laterally persistent and can occur on steep-sided coniform (e.g., walter, 1972, pl. 5, fi gs. 3, 4) and other (e.g., baicalia lacera, petrov & semikhatov, 2001, fi g. 5a, b) stromatolites. the fi ne-grained material ranges from micrite to microspar and can be quite heterogeneous, including calcifi ed fi laments, clots, peloids and bush-like structures, as well as spongy “vermiform” fabrics. the spar is typically radial-fi brous or blocky. the laminae are submillimetric to millimetric, occasionally centimetric (e.g. walter, 1972, pl. 12, fi g. 1) and range from isopachous with good inheritance to irregular and discon tinuous. proportions of light and dark bands range from predominantly dark to ~50% light. where dark layers predominate and sparry bands are thin and few, spar can occur in irregular fenestrae. in some cases, fi lamentous fabrics are well developed, as in the case of baicalia lacera which forms distinctive “platy” dark-light alternations (knoll & semikhatov, 1998; petrov & semikhatov, 2001, fi g. 6) (fig. 9) (see filamentous, below). bertrand-sarfati (1972, p. 112, pl. 13) described distinctive light-dark layers in mesoproterozoic baicalia mauritanica from atar. the dark layers are thin, generally <0.1 mm, whereas the light layers range up to 0.75 mm (fi g. 37). the dark layers are themselves composed of up to 5 or 6 thin leaves (“feuillets”) with a platy appearance (idem, pl. 13(1–3)) that she compared with that of baicalia lacera (idem, p. 113). tungussia nodosa. bertrand-sarfati (1972, p. 99, p. 187, pl. 19(1–3)) described millimetric micrite-micro spar (and locally sparite) alternations as “microstructure en tapis” (“micritic mat” in bertrand-sarfati, 1976, p. 256) in tungussia nodosa and t. aff. nodosa from atar. laminar fi brous crust and micritic peloidal laminae. in the pethei platform sami & james (1994, p. 116; 1996, p. 216, fi g. 6d) recognized “wavy microbialite” as a major component of peritidal facies. it consists of “stromatolites composed of cement laminae, 1–2 mm thick, separated by thin (< 1 mm), dark micritic surfaces and lenticular peloid grainstone laminae” (sami & james, 1994, p. 116). the laminae are laterally persistent, smoothly undulose and isopachous, with good inheritance and intervening troughs are occupied by fi ne sand. laminar fi brous crusts can be interbedded with detrital grains (sami & james, 1996, fi g. 5f) (and see gongylina, below). they attributed accretion to “com bination of cement precipitation and binding of peloids by smooth microbial mats” and interpreted it to form in lower intertidal and shallow subtidal conditions. sami & james (1994, p. 116) considered fenestral microbial laminite to be a low energy, upper intertidal to supratidal equivalent of laminar fi brous crust, consisting of “thin (1–2 mm), fi gu re 9: hybrid crust composed of submillimetric dark-light alternations. baicalia lacera. burovaya fm, turukhansk, siberia, latest mesoproterozoic (~1020 ma). the delicate, gently curved thin, even and persistent appearance of the dark layers, characteristic of “platy” baicalia lacera microstructure, may be fi lamentous in detail (knoll & semikhatov, 1998). reprinted from petrov & semikhatov (2001, fi g. 6a), with permission from elsevier. fi gu re 8: hybrid crust microfabrics (detail of fig. 7, conophyton garganicum). sparry and fi ne-grained layers can be interpreted as hybrid crust composed of thin layers of lithifi ed microbial mat (fi ne-grained) separated by thicker layers of surfi cial crust and/or early cavity fi ll (sparry) (cf. monty & hardie, 1976, fi g. 2b, see analogues, below). however, neomorphic spar aggradation cannot be ruled out. geologia croaticarobert riding: abiogenic, microbial and hybrid authigenic carbonate crusts: components of precambrian stromatolites 83 irregular to continuous, micrite and spar laminae with thin (< 1 mm), dark, clay-rich drapes” and irregular spar-fi lled fenestrae. the clotted microfabric “may represent either pelo ids or micrite-cement”. based on sami & james’ (1994, p. 116) inter pre tation of combined “cement” precipitation and mat bound peloids it could be regarded as a hybrid of isopachous, es sentially abiogenic, laminite and detrital carbonate, but if the peloids are in place microbial precipitates then this would essentially be a hybrid abio genic-biotic precipitated crust. 2.3.2. clotted-bushy-peloidal micrite clotted-peloidal-bushy micrite forms laminae interlayered with seafl oor precipitate and detrital micrite. the irregular micrite aggregates are often interspersed with microspar and spar, giving the lamina a relatively light appearance in thinsection. in addition to abundant synsedimentary “cement”-like precipitate, sami & james (1996, p. 213) recognized peloidal clotted micrite as “a signifi cant component (10–45%) of most stromatolitic laminae”. the clots consist of poorly defi ned 50–100 µm peloids and together with fi brous and blocky spar form laminae in “prone stromatolitic laminite” (sami & james, 1996, fi g. 7a, b). “prone microbial laminite” is a major component of pethei carbonates where it contributes signifi cantly to large elongate stromatolite domes (sami & james, 1993, p. 405, table 1). clotted-peloidal-bushy micrite aggregates can be very irregular, but locally distinctive vertically elongate shrub-like structures occur that are similar to present-day calcifi ed cyanobacterial sheaths (kah & riding, 2007). the shrubs are typically separated by spar, giving the layers a broadly fl occulent or palisade-like appearance. in the ~1200 ma society cliffs formation, laminae with shrubs form submillimetric laminae within isopachous laminite (kah & riding, 2007). the shrubs consist of fi ne microspar and are up to 600 μm high and 200 μm wide and have irregular margins and tend show vertical orientation on sloping surfaces. they closely resemble the calcifi ed thick irregular sheaths of present-day oscillatoriacean cyanobacteria (see riding & voronova, 1982). the society cliffs shrubs are associated with calcifi ed fi laments that are currently the oldest examples of sheathcalcifi ed cyanobacteria (kah & riding, 2007). somewhat similar fabrics have been fi gured from latest precambrian stromatolites as vesicularia (vologdin, 1962, pl. 39) and as “vermiform microstructure” in madiganites mawsoni from central australia (walter, 1972, pl. 1, fi gs. 1,2) of late cambrian age (lindsay et al., 2005; see also bertrandsarfati, 1976, p. 255), but these do not appear to be elements of hybrid deposits. 2.3.3. filamentous tangled to prostrate girvanella-like fi laments within sparmicrospar cement form relatively persistent platy to curved fl occulent submillimetric to millimetric layers. the fi laments may be constant diameter tubes with thin even-thickness walls, conforming to the calcifi ed cyanobacterial sheaths of girvanella (see riding, 1977a) but more commonly are less regular and less distinctly tubiform. they are tangled and irregular, often prostrate, and interspersed among microsparspar. filamentous microstucture with girvanella tubules, but without well developed interleaved sparite layers, occurs in some phanerozoic oncoid cortices (e.g., garwood & goodyear, 1924; biddle, 1983). in proterozoic stromatolites, layers of fi lamentous microstructure are commonly interleaved with millimetric sparite layers. some of these exhibit a distinctively striated “fi lmy” or “streaky” microstructure, as in baicalia lacera, tungussia confusa and other forms (knoll & semikhatov, 1998, table 1). microstructure with fi lament moulds was termed canaliphorida and filiformita by komar (1976, 1989; see also bertrand-sarfati et al., 1994, p. 182, fi g. 18). aitken (1989) recognized “dendriform” and “lamelliform” fabrics as framework components of stromatolitic bioherms in ~835 ma little dal group of nw canada. he remarked that these fabrics “are not typically stromatolitic” and that “sediment trapping may not have been the dominant process in their formation” (idem, p. 15). he described them as “cellular” and containing tubular and renalcis-like structures (idem, fi gs. 10–13). subsequently, turner et al. (1993, 2000a, fi g. 10b; 2000b) compared the tubules with girvanella and noted that the lamelliform fabric consists of alternating dark layers of “calcimicrobial fi laments” and lighter “more cement-rich” areas. little dal “hollow tubules with micritic walls” are fi gured by batten et al. (2004, fi g. 9b). knoll & semikhatov (1998, p. 410, fi gs. 3, 4) described well-preserved “fi lmy or platy” microstructure in early neoproterozoic baicalia lacera stromatolites from the chernaya rechka formation, igarka, siberia. they found it to be associated with “a distinctly fi lamentous microstructure” in which “laminae comprising densely interwoven to scattered, vertically or subhorizontally oriented fi laments are in ter spersed with layers of spongy or dense microspar”. they interpreted the 8–10 µm tubes as “sheaths of lpp-type (lyngbya, phormidium, plectonema) cyanobacteria and preserved as drusy microspar encrustations” (knoll & semikhatov, 1998, p. 411). similar baicalia lacera fabrics in the ~1ga burovaya formation of west-central siberia locally contain calcifi ed tubes resembling siphonophycus (petrov & semi khatov, 2001, p. 270). aitken (1989, p. 15–16) described “dendriform” and “lamelliform elements” as important components of little dal reefs in the mackenzie mountains. he regarded both as stromatolites with “unusual” or “unique” characteristics: thinwalled tubes and renalcis-like objects in dendriform element, and a reticulate “ladder-rung” arrangement that “may be formed by a meshwork of tubes” in lamelliform element. dendriform and lamelliform elements look quite similar in two of his illustrations (idem, fi gs. 10, 13). turner et al. (2000a, p. 185, 188) related these elements to growth stages in the reefs, with dendriform most common in stage iii and lamelliform in stage iv. their illustrations of dendriform elements geologia croatica geologia croatica 61/2–3 84 (turner et al., 2000a, fi g. 8a, b, e) show irregular closelyspaced centimetric digitate stromatolites with laminar-reticulate cores and marginal renalcis-like clots. they des cribe lamelliform elements as commonly steeply sloping (45–70°) and containing dark fi lamentous and more cement-rich light layers (turner et al., 2000a, fi g. 10b). these resemble the distinctive “fi lmy” microstructure of similar age baicalia lacera (petrov & semikhatov, 2001, fi gs. 5b, 6a) which also has steeply dipping laminae and, as noted above, quite possibly fi lamentous microstructure too. in the examples cited above, layers of fi lamentous fabric are generally interleaved with lighter, sparry, layers. if the sparry layers were lacking then the deposit would be in distinguishable from “skeletal stromatolite” (riding, 1977b) and “porostromate stromatolite” (monty, 1981). in addition to the little dal and chernaya rechka examples, calcifi ed fi laments reminiscent of girvanella are relatively widespread elsewhere in the neoproterozoic, e.g., in the ~750–700 ma draken fm (swett & knoll, 1985; knoll et al., 1993), ~725–675 ma svanbergfgellet fm (raaben, 1969), and ~700 ma upper eleonore bay supergroup, greenland (bertrand-sarfati & caby, 1976) (all references in knoll & semikhatov, 1998, p. 413). however, mesoproterozoic examples reported from the ~1200 ma society cliffs fm are currently the oldest known girvanella-like calcifi ed fi laments, and are associated with micritic bush-like structures also interpreted as calcified cyanobacteria (kah & riding, 2007). 2.3.4. boetsap laminae: microspar crusts well-developed relatively even lamination described from the neoarchaean campbellrand-malmani platform of south africa as boetsap lamination (sumner & grotzinger, 2004) also represent a type of hybrid sparry-microcrystalline crust, but is diffi cult to interpret due to uncertainty regarding the origin of the layers, which appear to be entirely microspar, with no sign of clotted or peloidal fabric. the main question is whether the microspar is entirely primary, or includes altered micrite. giant elongate domes in the campbellrand-malmani platform are dominated by millimetric layers of fi ne-grained dolomite (red-brown) and calcite (grey) that sumner & grotzinger (2004, p. 14–16) termed “boetsap lami nation”. they distinguished two main, equally abundant, components: (i) dark microcrystalline dolomite, varying 1–3 mm in thickness along a single lamina, commonly with peaked upper surfaces, (ii) thin (<1mm) uniform layers of light microcrystalline calcite and dolomite, showing a vertical fabric in thicker laminae. they interpreted the thicker layers with varied thickness as fi ne clastic carbonate, and the thinner uniform layers with vertical fabric as precipitated laminae. sumner & grotzinger (2004, p. 22) commented that “apparent paucity of micrite suggests that spontaneous precipitation of carbonate, i.e., whitings, was not common across seaward sides of the platform”, and noted that “micrite beds were not observed in shallow subtidal depositional environments” and “most intertidal to deep subtidal stromatolites and microbialites contain fi brous calcite cements”. but they also emphasized that extensive recrystallization made it diffi cult to interpret the fi ne-grained components (idem, p. 6, 8). at the boetsap section (sumner & grotzinger, 2004, fi g. 3) they estimated that elongate stromatolites are dominated by “microcrystalline” and “precipitated” fabrics, in which microcrystalline represents microspar to silt-sized crystals that “could have been either transported silt-sized carbonate or carbonate precipitated within microbial mats”, and precipitated represents “cement-like crystal textures”. they concluded that some elongate stromatolite mounds contain “a signifi cant component of clastic carbonate” whereas others, especially those better preserved, have “more precipitated textures” (idem, p. 16). boetsap laminae differ from isopachous laminite mainly by the presence of dark-light layering. interpretation of boetsap laminae presents problems to similar those of laminar fi brous crusts and micritic peloidal laminae (the key components of sami & james’ (1994, p. 116) “wavy microbialite”). both are hybrid deposits in which the origin of the fi ne-grained carbonate requires clarifi cation. boetsap lamination is regular but includes discontinuous layers (sumner & grotzinger, 2004, fi g. 11a) and the microspar to silt-sized crystals could represent detrital grains or microbial mat precipitate (sumner & grotzinger, 2004, fi g. 3). until these possibilities are resolved it is not possible to tell whether boetsap laminae, and therefore the “giant” domes of which they are an important component (sumner & grotzinger, 2004, p. 14, 16) are essentially sparry or hybrid crust. 2.4. sparry crust plus coarse grains abiogenic precipitates both cement and surfi cially veneer particulate carbonate. these hybrid “grainy crusts” are most distinctive where the grains are coarse. in the precambrian, examples of grains incorporated in seafl oor herringbone cal cite and in radial fi brous carbonate crusts have been des cribed, and some have been given stromatolite names, e.g., gongylina. 2.4.1. herringbone calcite with coarse grains herringbone calcite associated with grainstone forms laterally persistent centimetric to decimetric layers with scours and cross-lamination; the grainstone occurs as basal graded units or fi lls troughs between herringbone calcite domes (sumner, 1997a). in centimetric to decimetric “grainstone-precipitate” cycles in the subtidal gamohaan and frisco formations of the campbellrand-malmani platform, basal grainstones pass up into “precipitate-rich” beds (sumner, 2002, fi g. 2c), or grainstones fi ll troughs between stromatolitic “precipitate” domes (sumner, 1997a, table 1, p. 464–466). grainstone beds have basal scours and contain wave ripples. stromatolites are poorly laminated and dominated by herringbone calcite, which is also present between grains. synsedimentary lithifi cation is refl ected in vertical ripple propagation. geologia croaticarobert riding: abiogenic, microbial and hybrid authigenic carbonate crusts: components of precambrian stromatolites 85 2.4.2. radial fi brous crusts with silt and sand grains (e.g., gongylina, omachtenia) alternating submillimetric layers of particulate carbonate and radial fi brous crusts, infl uenced by synsedimentary scouring and micro-crosslamination, create distinctive dark-light well laminated rippled microstructures in laterally persistent decimetric to metric beds (knoll & semikhatov, 1998, p. 414–418). the pseudocolumnar to stratiform deposits formed by these grainy crusts form have been given form names within groups such as gongylina komar, 1966 (fig. 10) and omachtenia nuzhnov, 1967. omachtenia omachtensis with muddy to silty sediment, and gongylina differenciata with silt and sand, are regarded as characteristic of the mesoproterozoic (knoll & semikhatov, 1998, p. 418). hofmann (1969, table 13, p. 38) recognized that stratiform gongylina “appears to be nothing more than a form dependent on the periodic infl ux of sandor silt-sized material”. knoll & semikhatov (1998, p. 417–418, fi g. 11) agreed, and extended this inter pretation to include omachtenia omachtensis. they ruled out both trapping/binding and precipitation “by actively photosynthesizing mats”, and regarded these deposits as “mechanically emplaced sediments” encrusted by thin veneers of “cements”. they interpreted them as alternations of grains and seafl oor precipitates on peritidal fl ats locally associated with “micro digitate precipitates”. nonetheless, they con sidered that microbial mats appeared to have “covered and stabilized event beds and provided sites for the nucleation of carbonate crystals after degradation (knoll & semi khatov, 1998, p. 418). a variant of this mixed deposit is where grainy sediment accumulated lateral to domes, as in rocknest isopachous laminites where “precipitated laminae pinch out in adjacent depression, fi lled by both precipitated laminae and peloidal grains” (grotzinger & knoll, 1999, fi g. 3a). sami & james (1994, fi g. 6) noted “ooid grainstone with thin microbial laminae draping climbing ripples” in pethei shallowing cycles, and laminar fi brous crusts interbedded with detrital grains (sami & james, 1996, fi g. 5f). whereas grainy herringbone calcite deposits are centimetric-decimetric, in gongylina and omachtenia the radiaxial carbonate and grainy layers are both submillimetric. these deposits evidently form ed by alternation of sparry crust precipitation with sand and silt infl ux. they are likely to fi nd analogues, albeit in shallower water, in present-day hot-spring travertines and cave fl owstone. 2.4.3. crystal fans with coarse grains crystal pseudomorph fans also can be interbedded with crossstratifi ed grainstones, e.g., cheshire fm., zimbabwe (sum ner, 2002, fi g. 1c). 2.5. fenestrate microbialite these are thin beds of net-like masses of thin curved wispy dark layers, often rounded and contorted, that defi ne millimetric to centimetric lensoid to irregular areas of light-coloured cement that includes radial, sparry and herringbone calcite fabrics (fig. 11). the network is commonly structured by thinner dark layers draped from thicker dark subvertical “supports”. these distinctive deposits were recognized and described in detail from the campbellrand-malmani platform where they form thin (decimetric, sumner, 1997a, p. 462; sumner & grotzinger, 2004, fi g. 12) but laterally very extensive (sumner, 1997b, p. 315) beds. sumner (1997a, b) interpreted them as delicate convoluted microbial mats forming open networks (sumner & grotzinger, 2004, p. 16), with the thicker supports and laminated drapes being due to different microbial communities; the delicate wispy sheets being encrusted by calcite as they grew. varieties have been termed tented, cuspate, irregular columnar and plumose (sumner, 1997b) and, as a whole, fenestrate microbialites (sumner, 2000). they are typically closely associated with herringbone calcite, that preferentially veneers the vertical “supports”, together with bladed and blocky calcite cements (sumner, 1997b, p. 313). kerans & donaldson (1989, p.85, fi g. 6) described “massive accumulation of concave-upward, dishor bowlshaped algal plates ranging in size from 0.1 to 2 m” in the dismal lakes group, and termed them “cyanobacterial plate bioherms” (idem, fi g. 3). the plates, a few millimetres thick and a few centimetres long, are veneered by a few millimetres of “isopachous fi brous cement crust” (idem, fi g. 6b). these show some resemblance to fenestrate microbialites, but lack the net-like organization. in campbellrand-malmani car bonates, sumner (1997a, p. 458, fi g. 7) recognized “fi lmy laminae” draping over “supports creating complex microbial structures with complex voids” that combine to form cuspate, planar laminated, irregular columnar and contorted laminated structures, cemented and coated by herringbone calcite, in deep subtidal environments. sumner (1997b, p. 313) interpreted fenestrate microbialite as delicate thin microbial mats that provided irregular substrates for herringbone calcite cements that “precipitated contemporaneously with microbial growth”, and recognized that these deposits graded into herringbone calcite beds (sumner, 1997b, fi g. 7) that precipitated directly on the seafl oor. she suggested that present-day mineral encrusted fl oating substrate-attached mats may help understand fenestrate microbialites (sumner, 1997b, p. 311). fi gu re 10: diagrammatic representation of gongylina: submillimetric interlayers of sparry crust and coarse grains (after knoll & semikhatov, 1998, fi g. 11). geologia croatica geologia croatica 61/2–3 86 sumner (2000) reported fenestrate microbialites from greenstone belt carbonates at steep rock, ontario (~2.8 ga) and huntsman, zimbabwe (~2.8 ga) and regarded fenestrate microbialite essentially as “laminated mat encased in … fi brous marine cement” (sumner, 2002, fi g. 2b). sumner & grotzinger (2004, p. 16–17) described spatial distri butions of varieties of these deposits across the campbellrandmalmani platform, where they are most abundant in deeper water facies. they are associated with layers of “contorted laminated mat” (idem, fi g. 12) and may grade into less distinctive by grossly similar “fenestral laminite” that in turn is associated with isopachous laminite (idem, fi g. 9). bart ley et al. (2007, p. 216) reported, but did not fi gure, cuspate microbialite from the ~1300–1000 ma avzyan fm of the southern urals. fenestrate microbialites appear to lack fi lamentous microfabric (see sumner, 1997b, fi g. 5) but show some broad resemblance to “dendriform” and “lamelliform” little dal microfabrics. both essentially consist of thin wispy netlike layers that defi ne cement fi lled voids, but fenestrate microbialite microstructure is generally signifi cantly (~10–100 x) coarser than that of dendriform and lamelliform fabric (cf. sumner, 1997b, fi gs. 8, 10 with aitken, 1989 fi gs. 10, 13). nonetheless, the fi ne structure of lamelliform “ladderrung” fabric (aitken, 1989 fi g. 12) and laminated mat (sum ner, 1997b, fi g. 5a) is not dissimilar. 2.6. thrombolite the dense, peloidal, clotted and/or fi lamentous, micritic and microspar microfabrics typical of fine-grained crust occurs in thrombolites as well as stromatolites. thrombolites are distinguished by their lack of well-developed layering, and by their macroscopic patchy or clotted fabrics – typically millimetric to centimetric irregular dark masses (clots) in a lighter coloured matrix (aitken, 1967). they form beds and mo unds, sometimes in association with stromatolites, and in the proterozoic are rich in cement and/or fi laments. calcifi ed microbial thrombolites (riding, 2000, p. 192) are well known in the early palaeozoic (pratt & james, 1982; kennard & james, 1986). the earliest reported thrombolites are in the ~1.9 ga rocknest formation and are suggested to have formed “through the inorganic encrustation of probable microbial communities by marine cements” (kah & grotzinger, 1992, p. 305). no mesoproterozoic thrombolites have been reported, but there are several reports from the neoproterozoic. aitken & narbonne (1989) described thrombolites from the ~800 ma little dal group and the ediacaran bluefl ower formation of northwest canada. in the lower two-thirds of the little dal reefs “dendriform” and “lamelliform” stromatolites (aitken, 1989) are interlayed with thrombolitic deposits with fi lamentous, clotted and spongy “cellular” fabrics (turner et al., 1993; 2000a, fi gs. 6e, 8h,i) comparable with those of cambro-ordovician thrombolitic bioherms (turner et al., 1997, p. 441, 449; batten et al., 2004). thrombolites also occur in the latest neoproterozoic of oman (mattes & conway morris, 1990) and namibia (grotzinger et al., 2000, 2005; johnson & grotzinger, 2006). coincidence of relatively widespread neoproterozoic development of thrombolites with the development of fi la mentous fabric supports the view (kennard & james, 1986) that these thrombolites refl ect microbial calcifi cation. batten et al. (2004, p. 264, fi g. 10) suggested that neoproterozoic and early palaeozoic thrombolites generally developed in relatively deeper water than associated stromatolites. 3. discussion 3.1. present-day analogues the early search for present-day analogues for ancient stromatolites led from freshwater tufa (walcott, 1914; roddy, 1915) to marginal marine domes (black, 1933) and columns (logan, 1961). these discoveries strongly supported kal kowsky’s (1908) inference that stromatolites are essentially microbial deposits. they stimulated widespread studies of lithifi ed microbial mats, but optimism that such examples provide appropriate analogues for all ancient marine stromatolites diminished as studies of precambrian examples advanced (e.g., serebryakov, 1976, p. 633; grotzinger & knoll, 1999, p. 314). although there may be no present-day examples that closely resemble the very large domes and columns of the late archaean and early-mid proterozoic, nonetheless there are smaller examples in diverse environments that appear to contain comparable fab rics. fi gu re 11: fenestrate microbialite. late archaean campbellrandmalmani platform, south africa. width of fi eld ~ 16 cm. meshwork of rounded or angular to lunate fenestrae (white), generally <1cm in size, defi ned by thin curved dark layers, and crudely stacked in elongate, erect to sloping, masses a few centimeters in length. geologia croaticarobert riding: abiogenic, microbial and hybrid authigenic carbonate crusts: components of precambrian stromatolites 87 3.1.1. fine-grained crusts fine-grained crusts typically contain complex, dominantly fi ne-grained, carbonate microfabrics that refl ect precipitation in intimate association with organic matter, especially cell material and the extracellular polymeric substances that they produce, in microbial mats as a result of synsedimentary calcifi cation associated with processes such as oxygenic photosynthesis and bacterial sulphate reduction (e.g., trichet & défarge, 1995; visscher et al., 1998, 2000; reid et al., 2000; riding, 2000, table 1; arp et al., 2003; kuhl et al., 2003; dupraz et al., 2004; dupraz & visscher, 2005; baumgartner et al., 2006; kremer et al., 2008). these fi ne-grained microfabrics range from dense, through clotted, to peloidal and fi lamentous (riding, 2000, fi gs. 6, 7). individual, or associations of a few, micrite grains have been attributed to calcifi cation of bacterial cells after death (maurin & noël, 1977; krumbein, 1979; folk, 1993) and during life (thompson & ferris, 1990). clotted (grumous) microfabrics have commonly been linked with microbial processes (kaisin, 1925; pia, 1927, p. 36; hofmann, 1969, p. 40; bertrand-sarfati, 1976; monty, 1976, fi g. 27, 1981, p. 2). peloids – micritic aggregates of uncertain origin (mckee & gutschick, 1969) – include in place precipitates that have been variously interpreted as essentially abiogenic cements (macintyre, 1984, 1985) and as bacterial aggregates (chafetz, 1986). associations of clotted and peloidal micrite develop in microbial organic matter (monty, 1976, p. 229, fi g. 27e; zankl, 1993), including decaying sponges (reitner et al., 2000), and are commonly preserved in fossil sponges (mock & palmer, 1991; warnke, 1995). they have also been interpreted as products of calcifi ed bacterial biofi lm (riding, 2002). although the presence of heterotrophic bacteria has been suggested to lead to cyanobacterial calcifi cation (pentecost, 1991, p. 6; chafetz & buczynski, 1992) this may in part be related to the experimental growth medium used (arp et al., 2002). furthermore, such degraded sheaths are likely to be irregular in form and encrusted by carbonate to varying de grees, whereas fossils such as girvanella exhibit regular tube morphology in which wall-thickness remains constant in individual specimens, suggesting in vivo sheath impregnation (riding, 1977a, 2006). such sheath calcifi cation is linked to photosynthetic carbon uptake (golubic, 1973; pentecost, 1987, p. 134) particularly of hco3 -. some cyanobacterial sheaths are tubular and others are irregularly digitate and often show vertical orientation that creates a bush-like appearance (riding & voronova, 1982). these diverse examples indicate that a wide range of fi ne-grained clotted-peloidal-shrub-like and fi lamentous fabrics, often co-occurring, characterize lithifi ed microbial mats. 3.1.2. sparry crusts speleothem. cave carbonate precipitates include a wide array of deposits that include sparry subaqueous crusts, e.g., phreatic pool deposits (fairchild et al., 2007, fi g. 7.1b), and extensive fl owstone (e.g., burns et al., 1999, p. 499) that can also incorporate allochthonous grains. speleothem calcite exhibits palisade calcite (kendall & broughton, 1978). kendall & iannace (2001, fi g. 6c) fi gured stromatolitic crusts from a pleistocene rimstone dam from sor rento, italy, and also laminated dendrite crystals (idem, fi g. 8). they suggested (kendall & iannace, 2001, p. 695) that these might assist interpretation of similar lamination in freshwater stromatolites such as described by freytet & ver recchia (1999), and also the sub-millimetric micritemic rospar laminae typical of the problematic stromatolite-like structure archaeolithoporella. travertine. hot spring travertines can include crystalline crusts and shrub-like fabrics (chafetz & folk, 1984; guo & riding, 1992; riding, 2000, p. 196; pentecost, 2005, pl. 8c) that resemble some precambrian isopachous laminites, and dendritic fabrics, as well as alternations of sparry crusts and allochthonous grains such as in gongylina and omachtenia. calcrete. laminar calcretes include stromatolitic fabrics with sub-millimetric light-dark bands (read, 1976, pl. 3). some have been termed lichen stromatolites (klappa, 1979) and terrestrial stromatolites (wright, 1989), and can in clude diverse fabrics (see references in riding, 2000, p. 196). alkaline lake crusts. grotzinger & james (2000, p. 9) noted the scarcity of present-day analogues of seafl oor precipitated calcite and aragonite. they suggested that partial analogues may exist in non-marine thermal springs and also in alkaline lakes such as those of pyramid lake, nevada (e.g., benson, 1994). kazmierczak & kempe (2006, fi g. 3, p. 124) illustrate partially silicifi ed aragonite stromatolitic crusts from alkaline lakes of niuafo’ou island, tonga, that have with laminated, arborescent and tussock fabrics. they compared them with proterozoic and also palaeozoic ex amples. the stromatolites contain cyanobacterial remains (kazmierczak & kempe, 2006, fi g. 2) but do not appear to be precipitating at present (idem, p. 124). marine evaporative splash crusts. intertidal-supratidal carbonate crusts have been termed “pelagosite”, after the italian name pelagosa for the croatian island palagruža (see palache et al., 1951), and “coniatolite” (purser & loreau, 1973). these can be well-developed along evaporitive shorelines and intertidal radial-fi brous aragonite crusts up to 3cm thick on beach rock in the southern persian gulf (purser & loreau, 1973) form through repeated immersion and evaporation of slightly hypersaline seawater. such in durated crusts have been termed “marine cements” and compared with travertine and great salt lake cements (alsharhan & kendall, 2003, pl. 2, p. 230, 237). locally they are coated by cyanobacteria (alsharhan & kendall, 2003 p. 214) and may therefore provide examples of hybrid crusts. hofmann & jackson (1987, p. 969) compared proterozoic microdigitate stromatolite fabrics with the microstructure of the carbonate crusts described by purser & loreau (1973, p. 368). montanari et al. (2007) des cribed pelagosite from palagruža and hvar, croatia, as “microstroma tolite” and interpreted the light-dark laminae as annual layers. geologia croatica geologia croatica 61/2–3 88 hypersaline stromatolites. in the marginal marine sebkha el melah of se tunisia, 5500 bp stromatolites that formed on beachrock and serpulid bioherms at the margins of a restricted lagoon have clotted and radial fi brous aragonitic microfabrics (davaud et al., 1994, fi gs. 9, 10c, d). metric stromatolitic domes composed of aragonite also occur in the present-day great salt lake (eardley, 1938; carozzi, 1962; halley, 1976) and in late pleistocene lake lisan deposits of the dead sea (buchbinder, 1981). beachrock. aragonite cements are lithifying components in both beachrock and stromatolites near lee stocking island, exuma cays (whittle et al., 1993). beachrock at san salvador island, while differing in morphology from stocking island stromatolites (reid & browne, 1991; mac in tyre et al., 1996) exhibits similar fenestral layering (kindler & bain, 1993, fi g. 4b, p. 245). microbial infl uences on beachrock formation (krumbein, 1979) suggest a con nec tion with the formation of coarse-grained near beach stro matolites (e.g., stocking island and highborne cay, bahamas) that should be explored. subtidal marine “cement” crusts. research into marine lithifi cation during the 1960’s and 1970’s revealed thick fi brous calcite crusts, for example in late palaeozoic reefs (otte & parks, 1963), that were subsequently compared with holocene submarine cements (schroeder, 1972; james et al., 1976) and, in some cases, interpreted to have been precipitated directly on the seafl oor (e.g., mazzullo & cys, 1979, p. 918). these were often referred to as “cements” and this terminology has commonly been applied to similar precambrian sparry seafl oor precipitates. present-day examples are typically subtidal botryoidal crusts of aragonite and mg-calcite. well-documented examples from the belize fore-reef are restricted to millimetric to centimetric cavities (james & ginsburg, 1979, p. 117, fi gs. 6–5), and in some cases aragonite cement is intimately associated with peloidal silt (idem, fi gs. 6–15d, 6–17d). 3.1.3. hybrid crusts freshwater tufa. partial analogues for proterozoic stromatolitic hybrid crust are likely to exist in present-day evaporitic and freshwater carbonates. freshwater “tufa stromatolite” (riding, 2000, p. 191) is characterized by light-dark banded cyanobacterial deposits that commonly consists of fi lamentous, shrub-like and coarse spar fabrics (e.g., pia, 1933, p. 41–42; stirn, 1964; irion & müller, 1968; golubic, 1973; monty, 1976, fi g. 7; pentecost, 1995; freytet & plet, 1996; kano et al., 2003; andrews, 2005; pen tecost, 2005, pl. 14c, d). these intimate associations of sheath impregnation and encrustation (e.g., riding, 1977a; monty & mas, 1981, fi g. 18b) preserve seasonal variations in microbial growth and associated precipitation. bertrand-sarfati (1972, p. 29, 169, 188; 1976, p. 253) compared light-dark “fi lm” layering in mesoproterozoic atar stromatolites with present-day cyanobacterial mats from andros island (monty, 1965) and suggested that, for example in some conophyton and inzeria specimens, they may be seasonal (bertrand-sarfati, 1972, pl. 11(4), pl. 22(2)) or even virtually daily (bertrand-sarfati, 1976, p. 253). in this context, it is relevant to compare bertrand-sarfati’s (1976, fi g. 1b) mesoproterozoic fi lm microstructure with superposed layers of schizothrix (monty & hardie, 1976, fi g. 2b) in present-day andros mats. similarly, bertrand-sarfati et al. (1994, p. 178–184) compared “alternating micrite-microsparite laminae” and fi lamentous and tussocky fabrics in palaeogene fl uvio-lacustine stromatolites from france, with similar fabrics in proterozoic stromatolites. in late pleistocene and holocene marginal stromatolites of east african rift lakes, casanova (1994, fi g. 10a) described “doublets” composed of “light-coloured sparitic laminae and dark micritic laminae” as the “most frequent micro structure observed in lacustrine stromatolites”. although light-dark bands are widespread and often distinct in freshwater stromatolites, their interpretation may not be straightforward (pentecost, 2005, p. 38–40). monty (1976, p. 199–208) described the complexity of layering in andros and also fl uviatile mats. he noted that andros mats essentially show alternations of “whitish calcareous layers and brownish organic ones”, but emphasized their complexity, that can include layers that develop within mats (monty, 1976, p. 199, 204). fluviatile rivularia shows both broad seasonal bands that relate to inorganic precipitation and fi ner bands thought to relate to photosynthetic activity (pentecost, 1987, p. 125). as a result, the winter bands can be more heavily calcifi ed and light-coloured (pentecost, 1987, fi g. 6b; pentecost & spiro, 1990, p. 18). similarly, in fl uviatile tufas, irion & müller (1968, fi g. 3) recognized light sparry winter layers, and commented “as the algae do not grow in winter, pure layers of sinter are formed during this period” (idem, p. 165). on the other hand, in seasonal couplets from lake manyara and lake natron, tanzania, casanova (1994) interpreted the thinner (5–900 µm) organic rich micritic layers as forming during the dry season, and thicker (20–1500 µm) sparitic layers, with numerous erect ~1 µm diameter fi laments, representing rainy season growth of fi lamentous cyanobacteria (casanova, 1994, p. 212–213, fi gs. 10, 11). thus, in the fl uviatile tufas the light bands may be relatively inorganic sparry precipitates, whereas in the lake natron example the sparry layers represent rapid growth of erect cyanobacteria. in fact this latter case may also apply to some fl uviatile tufa too; e.g., irion & müller (1968, fi g. 4) show “dark layers … deposited during the winter” and “white layers, formed during the summer”. not surprisingly, therefore, there has been debate concerning controls on lamina formation in fl uviatile tufas (kano et al., 2003, p. 259; andrews & brasier, 2005, p. 413; andrews, 2005; pentecost, 2005, table 3). kano et al. (2003, p. 255) report reversed seasonal patterns at different sites: dense winter and porous summer laminae at one, and dense summer and porous winter laminae at another. in contrast, many studies report denser/micritic winter-spring layers and more porous/sparry summer layers at both north ame rican (e.g., chafetz et al., 1991) and european (e.g., jansgeologia croaticarobert riding: abiogenic, microbial and hybrid authigenic carbonate crusts: components of precambrian stromatolites 89 sen et al., 1999, fi g. 2d; and other references in and rews & brasier, 2005, p. 413). in addition to depositional processes, diagenetic effects are also probably important (arp et al., 2001; andrews & brasier, 2005, p. 419; pen tecost, 2005, fi gs. 8, 9). for example, fossil tufas in belgium possess “more sparry calcite laminae than the recent preci pitates” that have preferentially developed at particular horizons (janssen et al., 1999, fi g. 5). these studies suggest that interpretation of hybrid crust in ancient stromatolites will not be simple, although it remains possible that they too, in some cases, may be seasonal. travertine shrubs. the likelihood that microdigitate stro matolites are essentially inorganic has long been con sidered (grotzinger, 1986b; hofmann & jackson, 1987). however, based on similar structures (shrub travertine) in present-day hot spring travertines, they too may have combined inorganic and microbial components (chafetz & folk, 1984; guo & riding, 1994). these shrubs are typically a few millimetres to centimetres in size, but larger examples up to 8 cm long (chafetz & folk, 1984, p. 305, fi g. 8) resemble dendrites described from the upper pethei group by pope & grotzinger (2000). cave crusts. sparry cave crusts can be interleaved with fi ne-grained layers, e.g. fi ne dark laminae in cave popcorn, some of which may be microbial (thrailkill 1976; melim et al., 2001) in which case they could be regarded as hybrid crusts. nonetheless, “much cave popcorn contains thick layers of clear calcite or aragonite with no indication of organic involvement” (thrailkill, 1976, fi gs. 7–12, p. 83). cox et al. (1989) described cyanobacterial speleothem as subaerial stromatolite. marine evaporitive splash crusts. present-day abu dhabi crusts formed through repeated immersion and evaporation of slightly hypersaline seawater are ephemerally coated by cyanobacteria (alsharnan & kendall, 2003 p. 214) possibly develop interlayered sparry and microbial fabrics, and alternations of pellet micrite and fi brous aragonite layers occur in sub-recent dead sea stromatolites (druckman, 1981, fi g. 6). evaporite stromatolites. microbial mats in hypersaline environments can be colonized and be encrusted by evaporite minerals (e.g. kendall & skipwith, 1968; gerdes et al., 1993, pl. 13) and involved in the development of stro matolitic structures (aref, 1998, fi gs. 4a, 6b). these can contain calcifi ed microbial fi laments and show well-defi ned even la mination (rouchy & monty, 1981, fi gs. 7, 9; 2000, fi g. 1). miocene marine stromatolite. coniglio et al. (1988, p. 102, 105, fi gs. 3, 7) described a mid-miocene reefal platform veneered by a 1m thick dolomitized deep-water “stromatolite” bed, forming domes up to 10 m across, composed of micropeloidal and homogeneous mudstone that locally grades to fi brous fabric that they compared with calcitized aragonite cement. 3.1.4. fenestrate microbialite sumner (1997b, p. 311) envisaged that plumose and similar archaean fenestrate fabrics originated by synsedimentary lithifi cation of vertically tufted microbial fi lms, as in hot springs (e.g., walter et al., 1976) and in the pinnacle, columnar and lift-off mats of ice-covered lakes in antarctica (wharton 1994, fi g. 3). comparisons could also be suggested with cool and hot spring travertine fabrics, especially those with rounded millimetric to centimetric voids formed by precipitation on water and bubble surfaces; these (e.g., reis, 1926, p. 181; guo & riding, 1998, fi gs. 4, 5). gandin & wright (2007) interpreted campbellrand-malmani fenestrate fabrics as products of synsedimentary deformation of organic fi laments “exerted by the growth of evaporite nodules, during the coalescence of enterolithic folds”. 3.1.5. thrombolite neoproterozoic thrombolites have been compared with early palaeozoic examples (turner et al., 1997), but present-day analogues of these types of thrombolite have not been confi dently recognized. laval et al. (2000) suggested that fabrics within freshwater tufa mounds from pavilion lake, british columbia, might be analogous with those of cambrian thrombolitic reefs containing epiphyton and girvanella. this brief and very incomplete overview suggests that diverse partial analogues of sparry and hybrid crust deposits may be found in quaternary evaporitic, alkaline lake, and fresh water environments. none of these present-day deposits is known to create sparry crusts on the scale observed in the precambrian, e.g., in metric domes and cones. nonetheless, some should provide analogues for small crusts, and in particular for their microfabrics. 3.2. recognition and interpretation of precambrian stromatolitic crusts abiogenic precipitated stromatolites. awareness of the widespread existence of seafl oor precipitates that could be confused with lithifi ed microbial mats emerged gradually from studies of proterozoic, and subsequently archaean, stromatolites in the 1980’s (e.g., kerans, 1982; grotzinger, 1986a). this research led to critical reassessment of the nature and signifi cance of precambrian authigenic seafl oor carbonate crusts. grotzinger & read (1983) described microdigitate stromatolites as “cement laminae”, and grotzinger (1986b) considered the possibility that they were “entirely abiotic”. grotzinger (1989b, p. 11) drew attention to “the direct precipitation of stromatolitic laminae” and grotzinger & rothman (1996, p. 424) suggested that the growth of large early proterozoic stromatolites (jackson, 1989, fi g. 13) could “be accounted for exclusively by abiotic mechanisms, particularly where growth by precipitation is thought to be important”. grotzinger & knoll (1999, p. 343) noted that “the growth of abiotic marine crusts might substitute for mats and create the same end result” and grotzinger & james (2000, p. 7) commented “abiotic precipitates are morphologically and mineralogically identical to marine cements of phanerozoic age … with the striking difference that they do not simply fi ll voids but are widespread as direct precipitates on the sea fl oor itself”. these abiogenic precipitates were commonly referred to as seafl oor cements, geologia croatica geologia croatica 61/2–3 90 and this usage continued even after grotzinger & knoll (1995, p. 579) pointed out that seafl oor crusts/encrustations should be distinguished from “true cements which bind sediment particles and line voids” (e.g., kah & knoll, 1996, p. 79; pope et al., 2000, p. 1145). these investigations led to realization that abiogenic seafl oor precipitates were not only associated with stromatolites but also, in some cases, included them. thus, grotzinger & james (2000, p. 7, fi g. 5) summarized “sea-fl oor encrusting precipitates” as including microdigitate stromatolites, large crystal fans, isopachous laminites, herringbone calcite, and dendritic tufa. inclusion of isopachous laminites implied that abiogenic seafl oor crusts had not only formed micro digitate stromatolites on peritidal fl ats, but were also responsible for larger subtidal stromatolites that included palaeoproterozoic (jackson, 1989, fi gs. 6, 13; grotzinger & rothman, 1996, fi g. 1b; grotzinger & knoll, 1999, fi g. 3a; pope et al., 2000, fi g. 4; pope & grotzinger, 2000, fi g. 8) and late archaean (grotzinger & knoll, 1995, fi g. 1b; pope et al., 2000, fi g. 2d; sumner & grotz inger, 2004, fi g. 4a) examples. as a result, pope et al. (2000, p. 1149) considered “thinly laminated, isopachous stromatolites” “to have a largely abiotic origin”. fine-grained and sparry crust. the outline of previous research presented here suggests that three principal categories of well-preserved stromatolites can be recognized in the proterozoic: fine-grained, sparry and hybrid crust. although no present-day large subaqueous domes and cones with comparable structure are known, smaller present-day deposits can guide interpretation by providing partial analogues on two levels: microfabric and lamina structure. precambrian finegrained crust stromatolites resemble present-day lithifi ed microbial mats; in addition they conform to the great majority of phanerozoic normal marine stromatolites. in contrast, spar ry crust stromatolites have fabrics and structures that resem ble present-day speleothem fl owstone and hot-spring traver tine crystalline crust. this suggests that sparry crust stromatolites are essentially abiogenic aqueous precipitates, in the sense that their formation does not require biotic pro cesses and that they do not typically contain organically generated fabrics. sparry and fine-grained carbonate stromatolites can broadly resemble one another in stratiform to domical and columnar morphologies, but are generally distinct in fabric and lamina arrangement. fine-grained stromatolites have micritic and microspar microfabrics and their layering is relatively uneven to discontinuous and usually shows poor inheritance. sparry stromatolites have coarsely crystalline, equant spar or radialfi brous, microfabrics and their layering is even to isopachous, and laterally persistent layers with good inheritance. hybrid crust. since fine-grained and sparry stro matolites differ in fabric and detailed structure and, as interpreted here, differ in origin (microbial as opposed to abiogenic) it could well be argued that they need not be grouped together as stromatolites. however, the gap between fine-grained and sparry crust stromatolites is bridged by hybrid crust stromatolites, which typically consist of millimetric alternations of fi gu re 12: interpretive summary of precambrian authigenic crusts. principal components: sparry crust (essentially abiogenic precipitate), fine-grained crust (lithifi ed microbial mat), and allochthonous grains. intermediates: hybrid crust, coarse grained crust, and coarse grained mat. apart from allochthonous grains, each of the other fi ve components and intermediates has at some time been regarded as containing examples of stromatolites. examples of these stromatolitic deposits are indicated in red. geologia croaticarobert riding: abiogenic, microbial and hybrid authigenic carbonate crusts: components of precambrian stromatolites 91 sparry and fine-grained crust. these alternations are interpreted here as more-or-less regular, possibly seasonal, fl uctuations in microbial accretion and abiogenic precipitation. if this is correct then they refl ect a relatively balanced mix of abiotic and biotic processes. in the early-mid proterozoic, hybrid crust does not merely provide a link between finegrained and sparry crusts, but – in many subtidal carbonate platform environments – it appears to supercede them in abundance. for example, giant decametric subtidal domes of the palaeoproterozoic pethei group (sami & james, 1996), and mesoproterozoic burovaya formation (petrov & semi khatov, 2001) are composed of hybrid crusts, and one of the most distinctive stromatolites, conophyton, which locally forms decametric cones, also often has a hybrid crust composition (see walter, 1972). awareness of the importance of authigenic carbonate crusts in association with precambrian stromatolites was presaged by recognition of the role of synsedimentary lithifi cation in the formation of high-relief coniform stromatolites (donaldson, 1976; gebelein, 1976). conophyton and similar forms were already known to commonly contain distinctive streaky microstructure (komar et al., 1965; cloud & semikhatov, 1969, fi g. 2). clearer understanding of the signifi cance of these fabrics came from kerans’ (1982) (see grotzinger, 1989b, p. 10) suggestion that “cement crusts were precipitated on microbial laminae while stro matolites were growing”. similarly, grotzinger & knoll (1999, p. 329–330) later suggested that “the growth of abiogenic marine crusts might substitute for mats and create the same end result”. it thus appears that some stromatolites, such as some forms of conophyton, persistently had a dual abiogenic and microbial origin in which the fi ne-grained layers are essentially organic in origin (komar et al., 1965, p. 67; see walter, 1972, p. 86) and the precipitated spar, as kerens (1982) suggested, is essentially inorganic. sub se quently, sami & james (1994, p. 120) suggested that sparmicrite couplets refl ect alternation of “cement precipitation and microbial mat growth”. there is therefore a need to distinguish not only between what perry et al. (2007, p. 169) regarded as “microbially constructed stromatolites” and “abiotic, chemically precipitated carbonate crusts”, but also between these and hybrid crust stromatolites. crust discrimination. against earlier expectation (e.g., grotzinger & rothman, 1996; grotzinger & knoll, 1995, 1999) it now seems possible to apply details of fabric and lamina arrangement criteria to the recognition of fine-grained, hybrid, and sparry crusts (fig. 12). these criteria draw on observations developed by grotzinger & read (1983) in their recognition of the nature of micro digitate stromatolites, and by grotzinger (1989b, p. 11) when he drew attention to “the direct precipitation of stromatolitic laminae”. seafl oor encrusting precipitates typically consist of fans and layers of elongated fi brous crystals or dendrites (grotzinger & james, 2000, p. 7, fi g. 5). similarly, pope et al. (2000, p. 1142) found that “stromatolites with isopachous fi ne lamination” commonly have “radial fi brous texture”. pope et al. (2000) interpreted “isopachous stromatolites to have been dominated by chemogenic precipitation in the absence of microbial mats, and the growth of peloidal stromatolites to have been controlled by sedimentation in the presence of microbial mats” (idem, p. 1139), and added “thinly laminated isopachous stromatolites are considered to have a largely abiotic origin” (idem, p. 1149). thus, whereas lithifi ed microbial mats are characterized by micritic (clottedpeloidal-bushy), and sometimes grainy, fabrics and uneven to irregular layering, crystalline seafl oor precipitated crusts are characterized by sparry/radial-fi brous fabrics and more even and regular layering. hybrid crusts consist of millimetric alternations of these fabrics, in layers that are more regular than those usually present in fine-grained stromatolites, and less regular than those of sparry crust stromatolites (fig. 12). if these generalizations are valid, they signal an advance towards the holy grail of stromatolite studies – confi dent discrimination between abiogenic and microbial deposits. at the same time this recognizes hybrid crust as a key component of early-mid proterozoic stromatolites. realization of the existence of hybrid crust raises questions concerning its role in “giant” stromatolite formation, which may be signifi cant, as well as the nature of archaean stromatolites – specifi cally the relative importance of sparry, hybrid and fine-grained crusts in their formation. sparry crust with subordinate fine-grained crust. hyb rid crust as defi ned here generally exhibits relatively regular alternations of sparry and fine-grained crust. but in some cases the proportions of sparry and fine-grained crust are less balanced, as in the ~1200 ma society cliffs formation (kah & riding, 2007, p. 799) where fi ne-grained calcifi ed cyanobacterial crust layers are subordinate to sparry crust. this raises questions, apart from terminological ones. for example, is there an overriding control on hybrid crust de velopment? in fl uviatile and lacustrine tufa stromatolites, darklight layers appear to refl ect seasonal controls on microbial growth and carbonate precipitation, and this might also apply to precambrian hybrid crusts (see analogues, hybrid crusts, freshwater tufa, above). however, if subaqueous colonization of sparry crust by microbial mat were intermittent, in response to environmental factors operating on different and less regular time-scales, such as changes in water depth or salinity, then irregular alternations could be produced. these could include rare layers of fine-grained crust within sparry crust, and vice versa. further exploration of these possibilities and their controlling factors is required. 3.3. giant stromatolites the volumetric importance of stromatolites in the construction of precambrian carbonate platforms has long been emphasized (e.g., hoffman, 1969; grotzinger, 1990, p. 96) and the sizes of individual domes and cones can be remarkable. kerens & donaldson (1989, p. 84, fi gs. 4,5c) described upward transition from conical to domal stromatolites in the dismal lakes group, with cones up to 6 m diameter and 12 m in synoptic relief, and domes up to 40 m in geologia croatica geologia croatica 61/2–3 92 diameter and 10–15 m in synoptic relief. whereas such large cones appear to be relatively rare, metric to decametric domes are locally important subtidal components of precambrian carbonate platform (sumner & grotzinger, 2004, p. 16). archaean examples include steep rock (e.g., nisbet & wilks, 1989), campbellrand-malmani (e.g., young, 1932; truswell & eriksson, 1973, p.6; eriksson, 1977; beukes, 1987), and carawine (e.g., murphy & sumner, 2008). palaeoproterozoic examples include the whalen group, wyoming (hofmann & snyder, 1985, p. 843) (now regarded as probably correlative with the lower nash form fm., and therefore ~2.1 ga, bekker et al., 2003, p. 311), pethei group (e.g., hoffman, 1969), rocknest (grotzinger, 1986b, p. 833) and beechey fm (pelechaty & grotzinger, 1989, fi g. 9). a late mesoproterozoic example is the burovaya fm (petrov & semikhatov, 2001). neoproterozoic examples include little dal reefs (aitken, 1989), boot inlet fm (narbonne et al., 2000), and noonday dolomite (cloud et al., 1974; corsetti & grotzinger, 2005). in the latest archaean campbellrand-malmani platform, elongate mounds up to 10m across and 40m or more in length (beukes, 1987, p. 9; sumner & grotzinger, 2004, fi gs. 10, 14) contain occasional pseudomorph fans, and grainstone and “cement” layers, but their principal constituents are “boetsap-style lamellae” consisting of darker fi nely crys talline and lighter coarse sparry layers (sumner & grotzinger, 2004, p. 14, fi g. 11). archaean and palaeoproterozoic “giant mounds” are commonly steep-sided, elongate – presumably in response to current infl uence – and associated with decimetric fans and crusts (grotzinger, 1986b, p. 833; sumner & grotzinger, 2004, p. 16). grotzinger (1986b, p. 833) described rocknest stromatolitic mounds “5–40 m wide and with up to 4m of synoptic relief” locally “encrusted with layers of bladed, isopachous marine cement which may compose up to 50% of the bioherm”. at the groot boetsap river section, 45 km wnw of warrenton, south africa, a 135 m section of cambrellrand-malmani carbonates shows elongate stromatolite mounds up to 10 m wide, 40 m long and 2.5m relief dominated by crinkled lamination with good inheritance (truswell & ericksson, 1973, p. 6, fi g. 3) (fig. 13). where well-preserved microstructures are documented, these large domes often appear to be characterized by sparry or hybrid crusts. sami & james (1996, p. 217) emphasized the importance of “spar-micrite couplets” in pethei subtidal stromatolites, and in the late mesoproterozoic burovaya petrov & semikhatov (2001, fi g. 6, p. 269) noted that “cement-based microstructures” interlayered with clotted micrite create parallel lamination that “is remarkable in the giant dome facies for its smoothness and lateral extent”. it seems reasonable to infer that, in addition to providing increased strength and stability, a signifi cant abiogenic sparry crust component enhanced stromatolite accretion, contributing to their size and relief. conversely, it appears possible that few if any of the impressively large stromatolites that dominate the shallow subtidal areas of proterozoic carbonate platforms was solely composed of lithifi ed microbial mat. at the present-day, coarse grained agglutinated stromatolites (riding, 1991, p. 30) can have metric dimensions, as at lee stocking island (dill et al., 1986), but none is known that compares in size with the largest precambrian domes. nonetheless, there are phanerozoic examples where stro matolite size has increased with evaporative conditions. for example, metric domes occur in association with gypsum deposits in the mid-miocene of the eastern ukraine (peryt et al., 2004, fi g. 4). dolomitized laminar crusts, usually regarded as stromatolites and often associated with early marine cements, form large reefal masses in the late permian zechstein carbonate-evaporite cycles of northern europe (paul, 1995), and pope et al. (2000, p. 1143) drew attention to the similar age “very thinly and evenly laminated” metric stromatolites associated with evaporites in the zechstein basin of northeast england. fi gu re 13: stromatolite domes, tens of metres in extent, elongated in direction of view. late archaean campbellrand-malmani platform, dry bed of groot boetsap river, south africa. note generally even layers and good inheritance, even at this scale. persons at upper left indicate size. geologia croaticarobert riding: abiogenic, microbial and hybrid authigenic carbonate crusts: components of precambrian stromatolites 93 3.4. nature of archaean stromatolites whether giant archaean domes, such as those in steep rock and campbellrand-malmani carbonates, are also largely hyb rid crusts remains uncertain. their relatively even layering and good inheritance suggest that they are likely to be hybrid and/or sparry crusts. however, their microfabric preservation is generally poor and even in the relatively well-preserved cambellrand-malmani carbonates the nature of the boetsap laminae that are major components of the large domes is unclear. sumner & grotzinger (2004, p. 16) concluded that some elongate stromatolite mounds contain “a signifi cant component of clastic carbonate” whereas others, especially those better preserved, have “more precipitated textures”. but whether this was microbially mediated or essentially abiogenic is uncertain. thus, campbellrand-malmani giant domes may have been hybrid crusts; but there is also the possibility that they are more completely abiogenic. coniform stromatolites in the warrawoona group (~3.45 ga) of western australia show fi ne continuous laminae (lowe, 1980, 1983) and sparry microfabrics (hofmann et al., 1999, fi g. 3), although these could well be secondary (hofmann et al., 1999, p. 1259). the origins of pilbara stro matolites have been debated (e.g., lowe, 1994, 1995; buick et al., 1995). hofmann et al. (1999, p. 1260–1261) argued that examples ~50 km west of marble bar should be regarded as having “a biogenic component” based on features such as greater uniformity of laminae in the columns than in intervening areas, second-order corrugation that appear to have accreted upward, continuity of non-isopachous laminae, extensive regular development, steep slopes – often >40° and up to 75° – not known to be formed abiogenically. allwood et al. (2006, p. 717) supported a biogenic origin, including in their reasoning the diffi culty of accounting abiogenically for both the conical shape and the non-isopachous layering which has produced parallel-sided pseudocolumns, and also the more variable interspace laminae. furthermore, the only known present-day analogues for coniform stromatolites are structures formed by the infl uence of “vertically motile” microbes in hot springs such as yellowstone (walter et al., 1976; allwood et al., 2006, suppl. notes, p. 16). thus, although some of these pilbara structures superfi cially resemble isopachous laminites, they could differ from them in signifi cant details: specifi cally conical form and non-isopachous laminae with near vertical rather than upward expanding margins to the pseudocolumns. some pilbara stromatolites show well lami nated interspaces (see hofmann, 2000, fi g. 3b), sug gesting that these as well as the cones were seafl oor crusts. perhaps the outstanding question is whether coniform structures with vertical margins really cannot be produced by abiogenic precipitation. 3.5. secular changes and controls grotzinger & kasting (1993, p. 235, fi gs. 1, 2) pointed out that “massive, thick beds of marine cements”, common in the late archaean, gave way to “microdigitate stromatolites (tidal-fl at marine cement crusts)” in the palaeoproterozoic, and to “micritic whitings” in the neoproterozoic. they argued that “prolifi c precipitation of aragonite as giant botryoids up to 1 m in radius and magnesian calcite as stratigraphic sheets up to several meters thick” in the archaean refl ected elevated over-saturation for caco3 that subsequently declined over geological time (grotzinger & kasting, 1993, 235– 236). subsequent research provided further details of this sig nifi cant long-term trend (grotzinger & knoll, 1995; kah & knoll, 1996; sami & james, 1996; sum ner & grotzinger, 1996a, b). on an even larger time-scale, james et al. (1998, jsr) suggested that carbonate sedimentation was respectively dominated by massive seafl oor precipitates (archaean-palaeoproterozoic), molar-tooth mudstones and grainstones (meso-neoproterozoic), and burrowed and fossiliferous limestones (phanerozoic). in this context it seems possible that the early-mid proterozoic importance of hybrid crust stromatolites coincided with long-term transition from dominance of sparry crusts on archaean seafl oors to the rise to prominence of fine-grained stromatolites and thrombolites in the neoproterozoic. it may even be speculated that conditions favouring abiogenic sparry crust precipitation in the late archaean tended to inhibit microbial growth and substrate colonization, and that hybrid crusts developed as these conditions gradually became more favourable to microbial growth. perhaps conditions that alternately favoured microbial growth and abiogenic precipitation fl uctuated at relatively regular intervals, perhaps even seasonally. as sparry and hybrid crust stromatolites declined, fine-grained crust stromatolites, together with thrombolites, increased and probably become dominant during the neoproterozoic. from the mid-mesoproterozoic onward they locally contain conspicuous – presumably cyanobacterial – fi lamentous fabrics. the key long-term secular control on sparry crust development during the archaean and proterozoic has long been suggested to be seawater chemistry and its effect on carbonate nucleation and precipitation (grotzinger, 1990; grotzinger & kasting, 1993; sumner & grotzinger, 1996a). hybrid crust development can be integrated with this view. as seawater carbonate saturation declined, sparry crusts declined and fine-grained crusts increased, and during this long transition hybrid crusts were volumetrically abundant. in addition, cyanobacterial sheath calcifi cation could refl ect induction of co2-concentrating mechanisms in response to declining atmospheric co2 level, and this may have been primarily responsible for the mid-proterozoic appearance of widespread fi lamentous microbial fabrics in stromatolites and thrombolites (riding, 2006; kah & riding, 2007). thus, long-term patterns of stromatolite and thrombolite fabric development may be intimately related to large-scale changes in ocean-atmosphere composition. conditions of sparry crust formation, especially rapid accumulation, may have tended to inhibit microbial growth and colonization. as these conditions reduced, sparry and fine-grained crusts may increasingly have interacted to develop hybrid crust. lithifi ed microbial mat stromatolites geologia croatica geologia croatica 61/2–3 94 may therefore have antecedents in hybrid crusts that formed in environments of intense seafl oor carbonate precipitation. certainly it appears that many stromatolites older than ~1000 ma differ from present-day normal marine stromatolites characterized by fine-grained crust. conversely, marine sparry crusts, as both stromatolitic and other deposits, have been generally scarce since the mesoproterozoic (sumner & grotzinger, 2004, p. 2). however, they redeveloped briefl y in cap carbonates associated with rapid neoproterozoic deglaciation events (e.g., grotzinger & james, 2000, fi g. 7; sumner, 2002; nogueira et al., 2003) and also at times during the phanerozoic when “massive carbonate precipitation was favored” (grotzinger & knoll, 1995, p. 578). pope et al. (2000, p. 1139) suggested that isopachously laminated stromatolites “are dominated by chemogenic precipitation in the absence of microbial mats” and are “best developed atop proterozoic and paleozoic carbonate platforms that underlie major evaporite successions”. among several examples, they cited coatings on reefs in the silurian michigan basin, and also late permian crinkly stromatolites noted by smith (1981) from the zechstein basin of northern europe (pope et al., 2000, table 1, fi gs. 7, 9). they described the michigan isopachous stromatolites as commonly having “radial fi brous texture” (pope et al., 2000, p. 1142) which suggests that they are sparry crust, but the precise nature of the “crinkly” zechstein stromatolites remains uncertain. 4. summary seafl oor carbonate crusts. petrographic classifi cations emerging from the “carbonate revolution” of the 1950’s (e.g., folk, 1959; dunham, 1962) were primarily focused on phanerozoic marine examples. extensive research since then has shown that precambrian seafl oor carbonate crusts com prise a wide variety of deposits that accreted at the sediment-water interface at depths ranging from intertidal to deep subtidal. they occur as irregular sheets and also as domes and columns, some of which are decametric in scale. based on the information reviewed here, six categories can be recognized (table 1) of which four (fine-grained crust, sparry crust, hybrid crust, sparry crust plus grains) include at least some examples that have been regarded as stromatolites. interpretations based on partial present-day analogues suggest that fine-grained crust is lithifi ed microbial mat, sparry crust is essentially abiogenic precipitate, hybrid crust is a mixture in which microbial mat and abiogenic crusts alternate, and sparry crust plus grains forms where relatively large grains are incorporated into abiogenic crust (fig. 14). fine-grained crust is dominated by micritic and microsparitic (dense, clotted, peloidal, fi lamentous) microfabrics. these may contain fenestrae and incorporate allochthonous grains. in older examples micritic fabrics have often aggraded to microspar. it forms diverse stratiform, domical and columnar stromatolites with relatively uneven to discontinuous layers that usually show poor inheritance. it is also a key component of thrombolite. in the proterozoic, fine-grained crust is interleaved with sparry crust to form hybrid crust. in addition, it is the dominant components of many, usually relatively small (typically centimetric–decimetric) stromatolitic domes, columns and layers. palaeoproterozoic examples of these are less well-known, possibly due to poor fabric pre ser va tion. fine-grained crust thrombolites are relatively wide spread in the neoproterozoic. present-day analogues of fine-gra ined crust are diverse as lithifi ed microbial mats in non -marine and marine environments (see analogues). on this basis, proterozoic fine-grained crust is interpreted as an essentially biotic deposit resulting from in situ microbial mediation of carbonate precipitation, locally augmented by incorporation of allochthonous grains. sparry crust has coarsely crystalline, often radial-fi brous, microfabric. examples include large and small radial botryoids and crystal pseudomorphs, microdigitate stromatolitic “tufa”, dendrite, isopachous laminite, and herringbone calcite. these variously form domes, vertical crystal growths, and extensive layers. at least two categories, microdigitate “tufa” and isopachous laminite, create structures that have been generally regarded as stromatolites. these sparry crust stro matolites are characterized by even, often isopachous, laterally persistent layers with good inheritance, and have been most widely recognized in the palaeoproterozoic and meso pro terozoic, with microdigitate forms occupying peritidal envi ronments and isopachous laminite relatively deeper water facies. large subaqueous sparry crust domes, comparable with those of the proterozoic, are not known at the present-day. nonetheless, there is a wide variety of potential present-day analogues for sparry crust fabrics in smaller scale deposits, e.g., speleothem fl owstone, and hot-spring travertine crystalline crust (see analogues). these analogues suggest that sparry crust is essentially abiogenic, in the sense that its formation does not require biotic processes and that it does not typically contain organically generated fabrics. nonetheless, it can incorporate and veneer organisms and organic material. fi gu re 14: key features of crust discrimination, based on microfabric (fi ne-grained or sparry) and layer arrangement (irregular, poor inheritance; even, good inheritance). geologia croaticarobert riding: abiogenic, microbial and hybrid authigenic carbonate crusts: components of precambrian stromatolites 95 sparry crust has often been termed “seafl oor cement”, although it has been pointed out that this confl icts with the general usage of cement as precipitate between grains and within voids (grotzinger & knoll, 1995, p. 579). it has also been referred as “seafl oor crusts” and “inorganic crusts” (grotzinger & knoll, 1995, p. 578–579), “encrusting beds” (of bladed and herringbone calcite) and “microbialites coated by cements” (sumner & grotzinger, 1996a), “abiotic marine crusts” (grotzinger & knoll, 1999, p. 343), “encrusting marine cement directly on the growing stromatolite” (grotzinger & knoll, 1999, p. 329–330), “seafl oor-encrusting marine cement” (pope et al. 2000, p. 1145), and “seafl oor encrustations” (sumner, 2002). of the four general categories of subaqueous sparry crust recognized here, based on precambrian examples (table 1), three include stromatolitic deposits: (i) botryoidal fans and crystal pseudomorphs include small radial fi brous millimetric microbotryoids that build tarioufetia and tungussia (bertrand-sarfati, 1972); (ii) microdigitate stromatolites: small laminated columns of radial crystals (grotzinger & read, 1983; hof mann & jackson, 1987); (iii) isopachous laminite (jackson, 1989, sumner & grotzinger, 2004). in addition, thin (millimetric and submillimetric) sparry crust interlayered with fine-grained crust is an integral component of hybrid crust (see below). hybrid crust typically consists of light-dark, often milli metric, alternations of sparry and fine-grained crust. it builds stromatolites with well-developed even, although not usually isopachous, layering that is laterally quite persistent with generally good inheritance. this layering is therefore intermediate in regularity between that for sparry crust stro matolites and fine-grained crust stromatolites. hybrid crust appears to be a major component of palaeoproterozoic and mesoproterozoic stromatolites, which can include very large domical and conical examples. for example, metric to decametric stromatolite domes of hybrid crust are prominent components of some palaeoproterozoic (e.g., pethei group) and meso pro terozoic (e.g., burovaya formation) shallow subtidal carbo nate platform sequences. hybrid crust exhibits a variety of fine-grained crust microfabrics, and fi lamentous microfabric is locally common in hybrid crusts from the mid -proterozoic onward. light-dark millimetric alternations typical of hybrid crust have long been recognized in many precambrian stro matolites (e.g., vologdin, 1962; hofmann, 1969, fi g. 13), particularly in coniform examples (e.g., komar et al., 1965; walter, 1972, pls. 5, 6, 10, 12). for example, bert rand-sarfati et al. (1994) noted that microstructure consisting of alternations of micrite-microspar laminae “is one of the most frequently found in proterozoic stromatolites”. in the pethei group, sami & james (1994, p. 113; 1996, p. 217) emphasized the widespread importance of “spar-micrite couplets”, which are generally 1–2 mm thick, and comprise two broad groups: “laminar fi brous crusts” interlayered with micritic laminae (idem, fi g. 6d) and “clotted micrite pre ci pi tates arranged in vertical pillars and surrounded by fi brous and blocky precipitates” (idem, fi g. 7a,b). laminar fi brous crusts are here regarded as a possible hybrid form of iso pa chous la minite, and clotted micrite pillars are grouped with “bushy” microfabrics. knoll & semikhatov (1998), bart ley et al. (2000) and petrov & semikhatov (2001) also drew attention to the contrast between fi brous and mic ritic syn se dimentary precipitates in proterozoic stro matolites. large subaqueous hybrid crust domes, comparable with those of the proterozoic, are not known at the present-day, but potential analogues for their fabrics occur in freshwater stromatolites (see analogues). these examples tend to support the sami & james’ (1994, p. 120) suggestion that sparmicrite couplets refl ect alternation of “cement precipitation and microbial mat growth”. furthermore, layered alternations could refl ect secular changes that in some cases may be seasonal (bertrand-sarfati, 1972, pl. 11(4), pl. 22(2)). in present-day fl uviatile examples, the dark – microbial – layers often have fi lamentous fabric produced by fi lamentous cyanobacteria. in the proterozoic, hybrid crust appears to be responsible for some of the largest stromatolites known, with decametric dimensions. the size of these deposits might rapid accretion amplifi ed by combined effects of abiogenic precipitation and microbial growth. however, interpretation of hybrid crust can be complicated by poor preservation that hinders discrimination between detrital and microbial micrite, and blocky and radial spar (sami & james, 1994, p. 120). in particular, it can be diffi cult to decide (i) whether fi ne-grained carbonate represents primary siltor micrite-grade material; (ii) whether it is detrital or precipitated, (iii) the extent to which spar is void-fi lling or precipitated directly on the seafl oor, and (iv) the precise origins of putative microbial fabrics that may be clotted, peloidal, bush-like fabrics or fi la men tous. three broad categories of “spar-micrite couplet” are recog nized here, according to the dominant fi ne-grained fabric: (i) relatively dense, but also peloidal, microcrystalline carbonate with either generally even and extensive laminae or uneven and discontinuous laminae, (ii) clotted-bushy-peloidal micrite, (iii) fi lamentous. these categories can intergrade and co-mingle, both in terms of components and of laminar evenness and continuity. their discrimination is highly dependent on the quality of fabric preservation; micrite may be present locally (e.g., pethei, sami & james, 1996, p. 203) but even so is often converted to microcrystalline spar (sami & jam es 1996, p. 210) and in other cases is absent or hard to recog nize in others (e.g., campbellrand-malmani, sumner & grotzinger, 2004, p. 8). these categories should be regard ed as preliminary generalizations, and the examples selected require further comparison and probably subdivision. sparry crust plus grains. intercalation of sparry crust with allochthonous grains may prove to be a common deposit, but it has relatively rarely been reported. nonetheless, stromatolitic examples from the mesoproterozoic, in which radial fi brous sparry crust is interleaved with draped layers of silt and sand, have been given formal names, e.g., gongylina, omachtenia (semikhatov & knoll, 1998, fi gs. 9–11). these alternations of sparry crust precipitation with grainy sedimentation probably have partial analogues in hot-spring travertine and cave fl owstone (see analogues). geologia croatica geologia croatica 61/2–3 96 abiogenic and biogenic stromatolites. awareness of the existence of abiogenic stromatolites, emphasized by pope et al. (2000), has led to uncertainties regarding stromatolite defi nition and interpretation and has made it diffi cult to assess their signifi cance as indicators of both early life and environments. as corsetti & storrie-lombardi (2003, p. 649) noted, “it has been underappreciated that inorganic processes can produce stromatolites”, and perry et al. (2007, p. 169) recognized the need to discriminate between microbial stromatolites and abiotic carbonate crusts. pope et al. (2000, p. 1149) showed the way forward by regarding “thinly laminated isopachous stromatolites” as largely abiotic. the overview presented here suggests that precambrian stromatolites include not only essentially abiogenic (sparry crust) and lithifi ed microbial mat (fine-grained crust) examples, but also intimate mixtures of the two (hybrid crust). nonetheless, despite these complexities it seems likely that many proterozoic stromatolites retain suffi cient structural and fabric information to be distinguished as either sparry, hybrid or microcrystalline crust. this may also apply to well-preserved archaean stromatolites. if this is correct then it should be possible to use these distinguishing features to further elucidate the history of precambrian stromatolites and increase understanding of their signifi cance as environmental and biological indicators of past life and conditions. acknowledgement kath grey, hans hofmann and linda kah each generously provided stromatolite photographs. stimulating discussions with linda kah helped to motivate concept development. jam es wheeley and dave wright kindly made very helpful reviews. this article owes its existence to the persistence of tonći grgasović. alisa martek provided expert editorial ad vice. participation in the zagreb international fossil algae symposium was supported by the the royal society of london. to all, my grateful thanks. references aitken, j.d. (1967): classifi cation and environmental signifi cance of cryptalgal limestones and dolomites, with illustrations from the cambrian and ordovician of southwestern alberta. – j. sediment. petrol., 37, 1163–1178. aitken, j.d. (1989): giant “algal” reefs, middle/upper proterozoic little dal group (>770, <1200 ma), mackenzie mountains, n.w.t., canada. – in: geldsetzer, h.h.j., james, n.p. & tebbutt, g.e. (eds): reefs, canada and adjacent area. canadian soc. petrol. geol. memoir, 13, 13–23. aitken, j.d. & narbonne, g.m. (1989): two occurrences of precambrian thrombolites from the mackenzie mountains, northwestern canada. – palaios, 4, 384–388. allwood, a.c., walter, m.r., kamber, b.s., marshall, c.p. & burch, i.w. (2006): stromatolite reef from the early archaean era of australia. – nature, 441, 714–718. alsharhan, a.s. & kendall, c.g.st.c. (2003): holocene coastal carbonates and evaporites of the southern arabian gulf and their ancient analogues. – earth-sci. rev., 61, 191–243. andrews, j.e. (2005): palaeoclimatic records from stable isotopes in riverine tufas: synthesis and review. – earth-sci. rev., 75, 85–104. andrews, j.e. & brasier, a.t. (2005): seasonal records of climatic change in annually laminated tufas: short review and future prospects. – j. quaternary sci., 20, 411–421. aref, m.a.m. (1998): holocene stromatolites and microbial laminites associated with lenticular gypsum in a marine-dominated environment, ras el shetan area, gulf of aqaba, egypt. – sedimentology, 45, 245–262. arp, g., reimer, a. & reitner, j. (2002): calcifi cation of cyanobacterial fi laments: girvanella and the origin of lower paleozoic lime mud: comment. – geology, 30, 579–580. arp, g., reimer, a. & reitner, j. (2003): microbialite formation in seawater of increased alkalinity, satonda crater lake. – j. sediment. res., 73, 105–127. arp, g., wedemeyer, n. & reitner, j. (2001): fluvial tufa formation in a hard-water creek (deinschwanger bach, franconian alb, germany). – facies, 44, 1–22. awramik, s.m. & grey, k. (2005): stromatolites: biogenicity, biosignatures, and bioconfusion. – proceedings of spie 5906, 590601– 590609. awramik, s.m. & margulis, l. (1974): defi nition of stromatolite. – stromatolite newsletter, 2, 1–5. bartley, j.k., kah, l.c., mcwilliams, j.l. & stagner, a.f. (2007): carbon isotope chemostratigraphy of the middle riphean type section (avzyan formation, southern urals): signal recovery in a fold-and-thrust belt. – chem. geol., 237, 211–232. bartley, j.k., knoll, a.h., grotzinger, j.p. & sergeev, v.n. (2000): lithifi cation and fabric genesis in precipitated stromatolites and associated peritidal carbonates, mesoproterozoic billyakh group, siberia. – in: grotzinger, j.p. & james, n.p. (eds): carbonate sedimentation and diagenesis in the evolving precambrian world. sepm spec. publ. 67, 59–73. batten, k.l., narbonne, g.m. & james, n.p. (2004): paleoenvironments and growth of early neoproterozoic calcimicrobial reefs: platformal little dal group, northwestern canada. – precambrian res., 133, 249–269. baumgartner, l.k., reid, r.p., dupraz, c., decho, a.w., buckley, d.h., spear, j.r., przekop, k.m. & visscher, p.t. (2006): sulfate reducing bacteria in microbial mats: changing paradigms, new discoveries. – sediment. geol., 185, 131–145. bekker, a., karhu, j.a., eriksson, k.a. & kaufman, a.j. (2003): chemostratigraphy of paleoproterozoic carbonate successions of the wyoming craton: tectonic forcing of biogeochemical change?– precambrian res., 120, 279–325. benson, l.v. (1994): carbonate deposition, pyramid lake subbasin, nevada: 1. sequence of formation and elevational distribution of carbonate deposits (tufas). – palaeo., palaeo., palaeo., 109, 55–87. bertrand-sarfati, j. (1972): stromatolites columnaires du précambrien supérieur du sahara nord-occidental. – cnrs, paris, centre de recherches sur les zones arides, géologie, 14, xxxvii+ 245 p. bertrand-sarfati, j. (1976): pseudomorphoses de gypse en rosettes dans un calcaire cryptalgo-laminaire du précambrien inférieur (système du transvaal, afrique du sud). – bull. soc. géol. france, suppl., 1976(3), 99–102. bertrand-sarfati, j. & caby, r. (1976): carbonates et stromatolites du sommet du groupe d’éleonore bay (précambrien terminal) au canning land (groenland oriental). – bulletin grønlands geologiske undersøgelse, 119, 51 p. bertrand-sarfati, j., freytet, p. & plaziat, j.c. (1994): microstructures in tertiary nonmarine stromatolites (france). comgeologia croaticarobert riding: abiogenic, microbial and hybrid authigenic carbonate crusts: components of precambrian stromatolites 97 parison with proterozoic. – in: bertrand-sarfati, j. & monty, c. (eds): phanerozoic stromatolites ii. kluwer, dordrecht, 155– 191. beukes, n.j. (1987): facies relations, depositional environments and diagenesis in a major early proterozoic stromatolitic carbonate platform to basinal sequence, campbellrand subgroup, transvaal supergroup, southern africa. – sediment. geol., 54, 1–46. biddle, k.t. (1983): girvanella oncoids from middle to upper triassic allochthonous boulders of the dolomite alps, northern italy. – in: peryt, t.m. (ed.): coated grains. springer, berlin, 390–397. black, m. (1933): the algal sedimentation of andros island bahamas. – philos. t. roy. soc. london, ser. b: biol. sci., 222, 165–192. buchbinder, b. (1981): morphology, microfabric and origin of stromatolites of the pleistocene precursor of the dead sea, israel. – in: monty, c. (ed.): phanerozoic stromatolites. springer, berlin, 181–196. buick, r., groves, d.i. & dunlop, j.s.r. (1995): abiological origin of described stromatolites older than 3.2 ga: comment and reply. comment. – geology, 23, 191. burns, s.j., matter, a., frank, n. & mangini, a. (1999): speleothem-based climatic record from northern oman. – geology, 26, 499–502. cao, r. (1991): origin and order of cyclic growth pattern in mat-ministromatolite bioherms from the proterozoic wumishan formation, north china. – precambrian res., 52, 167–178. cao, r. & liang, y. (1974): on the classifi cation and correlation of the sinian system of china, based on a study of algae and stromatolites. – nanjing inst. geol. palaeont. memoir, 5, 1–26. carozzi, a.v. (1962): observations on algal biostromes in the great salt lake, utah. – j. geol., 70, 246–252. casanova, j. (1994): stromatolites from the east african rift, a synopsis. – in: bertrand-sarfati, j. & monty, c. (eds): phanerozoic stromatolites ii. kluwer, dordrecht, 193–226. chafetz, h.s. (1986): marine peloids; a product of bacterially induced precipitation of calcite. – j. sediment. petrol., 56, 812–817. chafetz, h.s. & buczynski, c. (1992): bacterially induced lithifi cation of microbial mats. – palaios, 7, 277–293. chafetz, h.s. & folk, r.l. (1984): travertines; depositional morphology and the bacterially constructed constituents. – j. sediment. petrol., 54, 289–316. chafetz, h.s., utech, n.m. & fitzmaurice, s.p. (1991): differences in the delta 18o and delta 13c signatures of seasonal laminae comprising travertine stromatolites. – j. sediment. res., 61, 1015–1028. cloud, p. & semikhatov, m.a. (1969): proterozoic stromatolite zonation. – am. j. sci., 267, 1017–1061. cloud, p., wright, l.a., williams, e.g., diehl, p.e. & walter, m.r. (1974): giant stromatolites and associated vertical tubes from the upper proterozoic noonday dolomite, death valley region, eastern california. – geol. soc. am. bull., 85, 1869–1882. coniglio, m., james, n.p. & aďssaoui, d.m. (1988): dolomitization of miocene carbonates, gulf of suez, egypt. – j. sediment. petrol., 58, 100–119. corsetti, f.a. & grotzinger, j.p. (2005): origin of tube structures in neoproterozoic post-glacial cap carbonates: example from noonday dolomite, death valley, united states. – palaios, 20, 348–362. corsetti, f.a. & storrie-lombardi, m.c. (2003): lossless compression of stromatolite images: a biogenicity index?– astrobiology, 3, 649–655. cox, g., james, j.m., leggett, k.e.a. & osborne, r.a.l. (1989): cyanobacterially deposited speleothems: subaerial stromatolites. – geomicrobiol. j., 7, 245–252. davaud, e., strasser, a. & jedoui, y. (1994): stromatolite and serpulid bioherms in a holocene restricted lagoon (sabkha el melah, southeastern tunisia). – in: bertrand-sarfati, j. & monty, c. (eds): phanerozoic stromatolites ii. kluwer, dordrecht, 131–151. de wet, c.b., frey, h.m., gaswirth, s.b., mora, c.i., rahnis, m. & bruno, c.r. (2004): origin of meter-scale submarine cavities and herringbone calcite cement in a cambrian microbial reef, ledger formation (u.s.a.). – j. sediment. res., 74, 914–923. dill, r.f., shinn, e.a., jones, a.t., kelly, k. & steinen, r.p. (1986): giant subtidal stromatolites forming in normal salinity waters. – nature, 324, 55–58. donaldson, j.a. (1963): stromatolites in the denault formation, marion lake, coast of labrador, newfoundland. – geol. surv. canada bull., 102, 33 p. donaldson, j.a. (1976): paleoecology of conophyton and associated stromatolites in the precambrian dismal lakes and rae groups, canada. – in: walter, m.r. (ed.): stromatolites. developments in sedimentology 20. elsevier, amsterdam, 523–534. druckman, y. (1981): sub-recent manganese-bearing stromatolites along shorelines of the dead sea. – in: monty, c. (ed.): phanerozoic stromatolites. springer, berlin, 197–208. dunham, r.j. (1962): classifi cation of carbonate rocks according to depositional texture. – in: ham, w.e. (ed.): classifi cation of carbonate rocks. aapg memoir, 1, 108–121. dupraz, c. & visscher, p.t. (2005): microbial lithifi cation in marine stromatolites and hypersaline mats. – trends microbiol., 13, 429–438. dupraz, c., visscher, p.t., baumgartner, l.k. & reid, r. p. (2004): microbe-mineral interactions : early carbonate precipitation in a hypersaline lake (eleuthera island, bahamas). – sedimentology, 51, 745–765. eardley, a.j. (1938): sediments of the great salt lake, utah. – aapg bull., 22, 1305–1411. eriksson, k.a. (1977): tidal fl at and subtidal sedimentation in the 2250 m.y. malmani dolomite, transvaal, south africa. – sediment. geol., 18, 223–244. fairchild, i.j., frisia, s., borsato, a. & tooth, a.f. (2007): speleothems. – in: nash, d.j. & mclaren, s.j. (eds): geochemical sediments and landscapes. blackwells, oxford, 200–245. fairchild, i.j., marshall, j.d. & bertrand-sarfati, j. (1990): stratigraphic shifts in carbon isotopes from proterozoic stromatolitic carbonates (mauritania): infl uences of primary mineralogy and diagenesis. – am. j. sci., 290a, 46–79. feldmann, m. & mckenzie, j.a. (1998): stromatolite-thrombolite associations in a modern environment, lee stocking island, bahamas. – palaios, 13, 201–212. folk, r.l (1993): sem imaging of bacteria and nannobacteria in carbonate sediments and rocks. – j. sediment. petrol., 63, 990–999. folk, r.l. (1959): practical petrographic classifi cation of limestones. aapg bull., 43, 1–38. freytet, p. & plet, a. (1996): modern freshwater microbial carbonates: the phormidium stromatolites (tufa-travertine) of southeastern burgundy (paris basin, france). – facies, 34, 219–237. freytet, p. & verrecchia, e.p. (1999): calcitic radial palisade fabric in freshwater stromatolites: diagenetic and recrystallized feature or physicochemical sinter crust?– sediment. geol., 126, 97– 102. geologia croatica geologia croatica 61/2–3 98 gandin, a. & wright, d.t. (2007): evidence of vanished evaporites in neoarchaean carbonates. – in: schreiber, b.c., lugli, s. & babel, m. (eds): evaporites through space and time. geological society, london, spec. publ. 285, 285–308. garwood, e.j. & goodyear, e. (1924): the lower carboniferous succession in the settle district and along the line of the craven faults. – quart. j. geol. soc. london, 80, 184–273. gebelein, c.d. (1976): the effects of the physical, chemical and biological evolution of the earth. – in: walter m.r. (ed.): stromatolites. developments in sedimentology 20. elsevier, amsterdam, 499–515. gerdes, g., claes, m., dunajtschik-piewak, k., riege, h., krumbein, w.e. & reineck, h-e. (1993): contribution of microbial mats to sedimentary surface structures. – facies 29, 61– 74. ginsburg, r.n. (1991): controversies about stromatolites: vices and virtues. – in: muller, d.w., mckenzie, j.a., & weissert, h. (eds): controversies in modern geology; evolution of geological theories in sedimentology, earth history and tectonics. academic press, london, 25–36. golubic, s. (1973): the relationship between blue-green algae and carbonate deposits. – in: carr, n. & whitton, b.a. (eds): the biology of blue-green algae. blackwell, oxford, 434–472. grey, k. & thorne, a.m. (1985): biostratigraphic signifi cance of stromatolites in upward shallowing sequences of the early proterozoic duck creek dolomite, western australia. – precambrian res., 29, 183–206. grotzinger, j.p. (1986a): evolution of early proterozoic passivemargin carbonate platform, rocknest formation, wopmay orogen, northwest territories, canada. – j. sediment. petrol., 56, 831–847. grotzinger, j.p. (1986b): cyclicity and paleoenvironmental dynamics, rocknest platform, northwest canada. – geol. soc. am. bull., 97, 1208–1231. grotzinger, j.p. (1989a): facies and evolution of precambrian carbonate depositional systems: emergence of the modern platform archetype. – in: crevello, p.d., wilson, j.l., sarg, j.f., & read, j.f. (eds): controls on carbonate platform and basin development. sepm spec. publ., 44, 79–106. grotzinger, j.p. (1989b): introduction to precambrian reefs. – in: geldsetzer, h.h.j., james, n.p. & tebbutt, g.e (eds): reefs, canada and adjacent areas. canad. soc. petrol. geol. mem., 13, 9–12. grotzinger, j.p. (1990): geochemical model for proterozoic stromatolite decline. – am. j. sci., 290-a, 80–103. grotzinger, j., adams, e.w. & schröder, s. (2005): microbial-metazoan reefs of the terminal proterozoic nama group (c. 550-543 ma), namibia. – geol. mag., 142, 499–517. grotzinger, j.p. & james, n.p. (2000): precambrian carbonates: evolution of understanding. – in: grotzinger, j.p. & james, n.p. (eds): carbonate sedimentation and diagenesis in the evolving precambrian world. sepm spec. publ., 67, 3–20. grotzinger, j.p. & kasting, j.f. (1993): new constraints on precambrian ocean composition. – j. geol., 101, 235–243. grotzinger, j.p. & knoll, a.h. (1999): stromatolites in precambrian carbonates: evolutionary mileposts or environmental dipsticks?– annu. rev. earth pl. sc., 27, 313–358. grotzinger, j.p. & read, j.f. (1983): evidence for primary aragonite precipitation, lower proterozoic (1.9–ga) rocknest dolomite, wopmay orogen, northwest canada. – geology, 11, 710–713. grotzinger, j.p. & rothman, d.r. (1996): an abiotic model for stromatolite morphogenesis. – nature, 383, 423–425. grotzinger, j.p., watters, w.a. & knoll, a.h. (2000): calcifi ed metazoans in thrombolite-stromatolite reefs of the terminal proterozoic nama group, namibia. – paleobiology, 26, 334–359. guo, l. & riding, r. (1992): microbial micritic carbonates in uppermost permian reefs, sichuan basin, southern china: some similarities with recent travertines. – sedimentology, 39, 37–53. guo, l. & riding, r. (1994): origin and diagenesis of quaternary travertine shrub facies, rapolano terme, central italy. – sedimentology, 41, 499–520. guo, l., & riding, r. (1998): hot-spring travertine facies and sequences, late pleistocene, rapolano terme, italy. – sedimentology, 45, 163–180. halley, r.b. (1976): textural variation within great salt lake algal mounds. – in: walter, m.r. (ed.): stromatolites. developments in sedimentology 20. elsevier, amsterdam, 435–445. hardie, l.a. (2003): secular variations in precambrian seawater chemistry and the timing of precambrian aragonite seas and calcite seas. – geology, 31, 785–788. hofmann, h.j. (1969): attributes of stromatolites. – geol. surv. canada paper, 69–39, 58 p. hofmann, h.j. (1971): precambrian fossils, pseudofossils, and problematica in canada. – geol. surv. canada bull., 189, 146 p. hofmann, h.j. (2000): archean stromatolites as microbial archives. – in: riding, r.e. & awramik, s.m. (eds): microbial sediments. springer, berlin, 315–327. hofmann, h.j. & jackson, j.d. (1987): proterozoic ministromatolites with radial fi brous fabric. – sedimentology, 34, 963–971. hofmann, h.j. & snyder, g.l. (1985): archean stromatolites from the hartville uplift, eastern wyoming. – geol. soc. am. bull., 96, 842–849. hofmann, h.j., grey, k., hickman, a.h. & thorpe, r.i. (1999): origin of 3.45 ga coniform stromatolites in warrawoona group, western australia. – geol. soc.am. bull., 111, 1256–1262. hoffman, p.f. (1969): proterozoic paleocurrents and depositional history of the east arm fold belt, great slave lake, northwest territories. – can. j. earth sci., 6, 441–462. hoffman, p.f. (1975): shoaling-upward shale-to-dolomite cycles in the rocknest formation (lower proterozoic), northwest territories, canada. – in: ginsburg, r.n. (ed.): tidal deposits. springer, berlin, 257–265. irion, g. & müller, g. (1968): mineralogy, petrology and chemical composition of some calcareous tufa from the schwäbische alb, germany. – in: müller, g. & friedman, g.m. (eds): recent developments in carbonate sedimentology in central europe. springer, berlin, 157–171. jackson, m.j. (1989): lower proterozoic cowles lake foredeep reef, n.w.t., canada. – in: geldsetzer, h.h.j., james, n.p. & tebbutt, g.e. (eds): reefs, canada and adjacent area. can. soc. petr. geol. memoir, 13, 64–71. james, n.p. & ginsburg, r.n. (1979): petrography of limestones from the wall and fore-reef. – in: james, n.p. & ginsburg, r.n. (eds): the seaward margin of belize barrier and atoll reefs. ias spec. publ. 3. blackwell, oxford, 111–152. james, n.p., ginsburg, r.n., marszalek, d.s. & choquette, p.w. (1976): facies and fabric specifi city of early subsea cements in shallow belize (british honduras) reefs. – j. sediment. petrol., 46, 523–544. geologia croaticarobert riding: abiogenic, microbial and hybrid authigenic carbonate crusts: components of precambrian stromatolites 99 james, n.p., narbonne, g.m. & sherman, a.g. (1998): molartooth carbonates: shallow subtidal facies of the midto late proterozoic. – j. sed. res., 68/5, 716-722. janssen, a., swennen, r., podoor, n. & keppens, e. (1999): biological and diagenetic infl uence in recent and fossil tufa deposits from belgium. – sediment. geol., 126, 75–95. jefferson, c.w. & young, g.m. (1989): late proterozoic orangeweathering stromatolite biostrome, mackenzie mountains and western arctic canada. – in: geldsetzer, h.h.j., james, n.p. & tebbutt, g.e. (eds): reefs, canada and adjacent area. – can. soc. petrol. geol. memoir, 13, 72–80. johnson, j. & grotzinger, j.p. (2006): effect of sedimentation on stromatolite reef growth and morphology, ediacaran omkyk member (nama group), namibia. – s. afr. j. geol., 109, 87–96. kah, l.c. & grotzinger, j.p. (1992): early proterozoic (1.9 ga) thrombolites of the rocknest formation, northwest territories, canada. – palaios, 7, 305–315. kah, l.c. & knoll, a.h. (1996): microbenthic distribution of proterozoic tidal fl ats: environmental and taphonomic considerations. – geology, 24, 79–82. kah, l.c. & riding, r. (2007): mesoproterozoic carbon dioxide levels inferred from calcifi ed cyanobacteria. – geology, 35, 799–802. kaisin, f. (1925): les calcaires oolithiques de l’étage viséen. – ann. soc. sci. bruxelles, 44, 365. kalkowsky, e. (1908): oolith und stromatolith im norddeutschen buntsandstein. – zeitschr. deutsc. geol. gesellsch., 60, 68–125. kano, a., matsuoka, j., kojo, t. & fujii, h. (2003): origin of annual laminations in tufa deposits, southwest japan. – palaeo., palaeo., palaeo., 191, 243–262. kazmierczak, j. & kempe, s. (2006): genuine modern analogues of precambrian stromatolites from caldera lakes of niuafo‘ou island, tonga. – naturwissenschaften, 93, 119–126. kendall, a.c. & broughton, p. (1978): origin of fabrics in speleothems composed of columnar calcite crystals. – j. sediment. petrol., 48, 519–538. kendall, a.c. & iannace, a. (2001); “sediment”-cement relationships in a pleistocene speleothem from italy: a possible analogue for “replacement” cements and archaeolithoporella in reefs. – sedimentology, 48, 681–698. kendall, c.g.st.c. & skipwith, p.a. d’e. (1968): recent algal mats of a persian gulf lagoon. – j. sediment. petrol., 38, 1040– 1058. kennard, j.m. & james, n.p. (1986): thrombolites and stromatolites; two distinct types of microbial structures. – palaios, 1, 492– 503. kerans, c. (1982): sedimentology and stratigraphy of the dismal lakes group, proterozoic, northwest territories. – unpublished phd thesis, carleton university, ottawa, canada. kerans, c. & donaldson, j.a. (1989): deepwater conical stromatolite reef, sulky formation (dismal lakes group), middle proterozoic, n.w.t. – in: geldsetzer, h.h.j., james, n.p. & tebbutt, g.e. (eds): reefs, canada and adjacent area. can. soc. petrol. geol. memoir, 13, 81–88. kindler, p. & bain, r.j. (1993): submerged upper holocene beachrock on san salvador island, bahamas: implications for recent sealevel history. – geol. rundsch., 82, 241–247. klappa, c.f. (1979): lichen stromatolites: criterion for subaerial exposure and a mechanism for the formation of laminar calcretes (caliche). – j. sediment. petrol., 49, 387–400. knoll, a.h. & semikhatov, m.a. (1998): the genesis and time distribution of two distinctive proterozoic stromatolite microstructures. – palaios, 13, 408–422. knoll, a.h., fairchild, i.j. & swett, k. (1993): calcifi ed microbes in neoproterozoic carbonates; implications for our understanding of the proterozoic/ cambrian transition. – palaios, 8, 512– 525. komar, v.a. (1966): stromatolites of the upper precambrian sediments of the north of the siberian platform, and their stratigraphic signifi cance. – nauka, moscow, 122 p. [in russian]. komar, v.a. (1976): classifi cation of stromatolites according to microstructure. – in: palaeontology of the precambrian and early cambrian, all union symposium, novosibirsk, ussr, p. 41–43. [in rus sian]. komar, v.a. (1989): classifi cation of the microstructures of the upper precambrian stromatolites. – himalayan geology, 13, 229–238. komar, v.a., raaben, m.e. & semikhatov, m.a. (1965): conophyton in the riphean of the ussr and their stratigraphic importance. – trudy geological institute, leningrad, 131, 72 p. [in russian]. krebs, w. (1969): early void-fi lling cementation in devonian fore-reef limestones (germany). – sedimentology, 12, 279–299. kremer, b., kazmierczak, j. & stal, l.j. (2008): calcium carbonate precipitation in cyanobacterial mats from sandy tidal fl ats of the north sea. – geobiology, 6, 46–56. krumbein, w.e. (1979): photolithotrophic and chemoorganotrophic activity of bacteria and algae as related to beachrock formation and degradation (gulf of aqaba, sinai). – geomicrobiol. j., 1, 139– 203. krumbein, w.e. (1983): stromatolites – the challenge of a term in space and time. – precambrian res., 20, 493–531. kuhl, m., fenchel, t. & kazmierczak, k. (2003): growth, structure and calcifi cation potential of an artifi cial cyanobacterial mat. – in: krumbein, w.e., paterson, d. & zavarzin, g. (eds): fossil and recent biofi lms, a natural history of life on earth. kluwer, dordrecht, 77–102. laval, b., cady, s.l., pollack, j.c., mckay, c.p., bird, j.s., grotzinger, j.p., ford, d.c. & bohm, h.r. (2000): modern freshwater microbialite analogues for ancient dendritic reef structures. – nature, 407, 626–629. lehmann, p. (1978): deposition, porosity evolution, and diagenesis of the pipe creek jr. reef (silurian), grant county, indiana. – unpublished ms thesis, university of wisconsin, madison, usa, 234 p. liang, y., cao, r.-j., zhang, l., qiu, s., xiao, z., cao, r.-g., duan, j., du, r., bu, j. & gao, z. (1984): pseudogymnosolenaceae of the late precambrian of china. – scientia sinica, b27 (5), 534–546. liang, y., zhu, s., zhang, l., cao, r., gao, z. & bu, d. (1985): stromatolite assemblages of the late precambrian in china. – precambrian res., 29, 15–32. lindsay, j.f., kruse, p.d., green, o.r., hawkins, e., brasier, m.d., cartlidge, j. & corfield, r.m. (2005): the neoproterozoic-cambrian record in australia: a stable isotope study. – precambrian res., 143, 113–133. logan, b.w. (1961): cryptozoon and associated stromatolites from the recent, shark bay, western australia. – j. geol., 69, 517–533. lowe, d.r. (1980): stromatolites 3,400–3,500 myr old from the archean of western australia. – nature, 284, 441–443. geologia croatica geologia croatica 61/2–3 100 lowe, d.r. (1983): restricted shallow-water sedimentation of early archean stromatolitic and avaporitic strata of the strelley pool chert, pilbara block, western australia. – precambrian res., 19, 239–283. lowe, d.r. (1994): abiological origin of described stromatolites older than 3.2 ga. – geology, 22, 387–390. lowe, d.r. (1995): abiological origin of described stromatolites older than 3.2 ga: comment and reply. reply. – geology, 23, 191–192. macgregor, a.m. (1941): a pre-cambrian algal limestone in southern rhodesia. – trans. geol. soc. s. africa, 43 (1940), 9–16. macintyre, i.g. (1984): extensive submarine lithifi cation in a cave in the belize barrier reef platform. – j. sediment. petrol., 54, 221– 235. macintyre, i.g. (1985): submarine cements – the peloidal question. – in: schneidermann, n. & harris, p.m. (eds): carbonate cements. sepm spec. publ. 36, 109–116. macintyre, i.g., reid, r.p. & steneck, r.s. (1996): growth history of stromatolites in a holocene fringing reef, stocking island, bahamas. – j. sediment. res., 66, 231–242. martin, a., nisbet, e.g. & bickle, m.j. (1980): archaean stromatolites of the belingwe greenstone belt, zimbabwe (rhodesia). – precambrian res., 13, 337–362. mattes, b.w. & conway morris, s. (1990): carbonate/evaporite deposition in the late precambrian-early cambrian ara formation of southern oman. – in: robertson, a.h.f., searle, m.p. & ries, a.c. (eds): the geology and tectonics of the oman region. geol. soc. london, spec. publ., 49, 617–636. maurin, a.f. & noël, d. (1977): a possible bacterial origin for famennian micrites. – in: flügel, e. (ed.): fossil algae, recent results and developments. springer, berlin, 136–142, mazzullo, s.j. & cys, j.m (1979): marine aragonite sea-fl oor growths and cements in permian phylloid algal mounds, sacramento mountains, new mexico. – j. sediment. res., 49, 917–936. mcgovney, j.e. (1989): thornton reef, silurian, northeastern illinois. – in: geldsetzer, h.h.j., james, n.p. & tebbutt, g.e (eds): reefs, canada and adjacent area. can. soc. petrol. geol. memoir, 13, 330–338. mckee, e.d. & gutschick, r.c. (1969): analysis of lithology. – in: mckee, e.d. & gutschick, r.c. (eds): history of the redwall limestone of northern arizona. – geol. soc. am. mem., 114, 97– 124. mcloughlin, n., wilson, l.a., & brasier, m.d. (2008): growth of synthetic stromatolites and wrinkle structures in the absence of microbes – implications for the early fossil record. – geobiology, 6, 95–105. melim, l.a., shinglman, k.m., boston, p.j., northup, d.e., spilde, m.n. & queen, j.m. (2001): evidence for microbial involvement in pool fi nger precipitation, hidden cave, new mexico. – geomicrobiol. j., 18, 311–329. mock, s.e. & palmer, t.j. (1991): preservation of siliceous sponges in the jurassic of southern england and northern france. – j. geol. soc. london, 148, 681–689. montanari, a., bice, d., druschel, g., mariani, s., marshall, c., olcott, a., sharp, w., tigue, t. & vučetić, m. (2007): rediscovering pelagosite: a mediterranean “microstromatolite” recording recent climate cycles. – geophys. res. abstracts, 9, 01555. monty, c. (1965): recent algal stromatolites in the windward lagoon, andros island, bahamas. – ann. soc. géol. belgique, 88, 269– 276. monty, c.l.v. (1976): the origin and development of cryptalgal fabrics. – in: walter, m.r. (ed.): stromatolites. developments in sedimentology 20. elsevier, amsterdam, 193–249. monty, c.l.v. (1981): spongiostromate vs. porostromate stromatolites and oncolites. – in: monty, c.l.v. (ed.): phanerozoic stromatolites. springer, berlin, 1–4. monty, c.l.v. & hardie, l.a. (1976): the geological signifi cance of the freshwater blue-green algal calcareous marsh. – in: walter, m.r. (ed.): stromatolites. developments in sedimentology 20. elsevier, amsterdam, 447–477. monty, c. & mas, j.r. (1981): lower cretaceous (wealden) bluegreen algal deposits of the province of valencia, eastern spain. – in: monty, c. (ed): phanerozoic stromatolites. springer, berlin, 85– 120. murphy, m.a. & sumner, d.y. (2008): variations in neoarchean microbialite morphologies: clues to controls on microbialite morphologies through time. – sedimentology, 55/5, 1189-1202. narbonne, g.m., james, n.p., rainbird, r.h. & morin, j. (2000): early neoproterozoic (tonian) patch reef complexes, victoria island, arctic canada. – in: grotzinger j.p. & james n.p. (eds): carbonate sedimentation and diagenesis in the evolving precambrian world. sepm spec. publ. 67, 163–177. nisbet, e.g. & wilks, m.e. (1989): archaean stromatolite reef at steep rock lake, atikokan, northwestern ontario. – in: geldsetzer, h.h.j., james, n.p. & tebbutt, g.e. (eds): reefs, canada and adjacent area. can. soc. petrol. geol. memoir, 13, 89–92. nogueira, a.c.r., riccomini, c., sial, a.n., moura, c.a.v. & fairchild, t.r. (2003): soft-sediment deformation at the base of the neoproterozoic puga cap carbonate (southwestern amazon craton, brazil): confi rmation of rapid icehouse to greenhouse transition in snowball earth. – geology, 31, 613–616. nuzhnov, s.v. (1967): riphean deposits of the south-eastern margin of the siberian platform. – nauka, moscow, 160 p. [in russian]. otte, c., jr. & parks, j.m., jr. (1963): fabric studies of virgil and wolfcamp bioherms, new mexico. – j. geol., 71, 380–396. palache, c., berman, h. & frondel, c. (1951): the system of mineralogy of james dwight dana and edward salisbury dana, yale university 1937–1892, volume ii: halides, nitrates, borates, carbonates, sulfates, phosphates, arsenates, tungstates, molybdates, etc., 7th edition. – john wiley and sons, new york, 183 p. paul, j. (1995): stromatolite reefs of the upper permian zechstein basin (central europe). – facies, 32, 28–31. pelechaty, s.m & grotzinger, j.p. (1989): stromatolite bioherms of a 1.9 ga foreland basin carbonate ramp, beechey formation, kilohigok basin, northwest territories. – in: geldsetzer, h.h.j., james, n.p. & tebbutt, g.e. (eds): reefs, canada and adjacent area. can. soc. petrol. geol. memoir, 13, 93–104. pentecost, a. (1987): growth and calcifi cation of the freshwater cyanobacterium rivularia haematites. – p. roy. soc., london, b 232, 125–136. pentecost, a. (1991): calcifi cation processes in algae and bacteria. – in: riding r. (ed.): calcareous algae and stromatolites. springer, berlin, 3–20. pentecost, a. (1995): signifi cance of the mineralizing bioniche in a lyngbya (cyanobacterium) travertine. – geomicrobiol. j., 13, 213– 222. pentecost, a. (2005): travertine. – springer, berlin, 445 p. pentecost, a. & spiro, b. (1990): stable carbon and oxygen isotope composition of calcites associated with modern freshwater cyanobacteria and algae. – geomicrobiol. j., 8, 17–26. geologia croaticarobert riding: abiogenic, microbial and hybrid authigenic carbonate crusts: components of precambrian stromatolites 101 perry, r.s., mcloughlin, n., lynne, b.y., sephton, m.a., oliver, j.d., perry, c.c., campbell, k., engel, m.h., farm er, j.d., brasier, m.d. & staley, j.t. (2007): defi ning biominerals and organominerals: direct and indirect indicators of life. – sediment. geol., 201, 157–179. peryt, t.m., peryt, d., jasionowski, m., poberezhskyy, a.v. & durakiewicz, t. (2004): post-evaporitic restricted deposition in the middle miocene chokrakian-karaganian of east crimea (ukraine). – sediment. geol., 170, 21–36. petrov, p.yu. & semikhatov, m. a. (2001): sequence organization and growth patterns of late mesoproterozoic stromatolite reefs: an example from the burovaya formation, turukhansk uplift, siberia. – precambrian res., 111, 257–281. pia, j. (1927): thallophyta. – in hirmer, m.: handbuch der paläobotanik. oldenbourg, munich, 1, 31–136. pia, j. (1933): die rezenten kalksteine. – mineralogische und petrologische mitteilungen, neue folge, ergänzungsband, 1–420. pope, m.c. & grotzinger, j.p. (2000): controls on fabric development and morphology of tufas and stromatolites, uppermost pethei group (1.8 ga), great slave lake, northwest canada. – in: grotzinger, j.p. & james, n.p. (eds): carbonate sedimentation and diagenesis in the evolving precambrian world. sepm spec. publ., 67, 103–121. pope, m.c., grotzinger, j.p., & schreiber, b.c. (2000): evaporitic subtidal stromatolities produced by in situ precipitation: textures, facies associations, and temporal signifi cance. – j. sediment. res., 70, 1139–1151. pratt, b.r. & james, n.p. (1982): cryptalgal-metazoan bioherms of early ordovician age in the st. george group, western newfoundland. – sedimentology, 29, 543–569. purser, b.h. & loreau, j.p. (1973): aragonitic supratidal encrustations on the trucial coast, persian gulf. – in: purser, b.h. (ed.): the persian gulf. springer, berlin, 343–376. raaben, m.e. (1980): microstromatolites – a characteristic element of the lower proterozoic stromatolite assemblage. – doklady akademia nauk sssr, 250, 734–737 [in russian]. raaben, m.e. (2005): archean and proterozoic ministromatolites: taxonomic composition of successive assemblages. – stratigr. geol. correlation, 13, 367–379. read, j.f. (1976): calcretes and their distinction from stromatolites. – in: walter, m.r. (ed.): stromatolites. developments in sedimentology 20. elsevier, amsterdam, 55–71. reid, r.p. & browne, k.m. (1991): intertidal stromatolites in a fringing holocene reef complex, bahamas. – geology, 19, 15–18. reid, r.p., visscher, p.t., decho, a.w., stolz, j.f., bebout, b.m., dupraz, c., macintyre, i.g., paerl, h.w., pinckney, j.l., prufert-bebout, l., steppe, t.f. & desmarais, d.j. (2000): the role of microbes in accretion, lamination and early lithifi cation of modern marine stromatolites. – nature, 406, 989–992. reis, o.m. (1926): zusammenfassung über die im ries südlich von nördlingen auftretenden süβwasserkalke und ihre entstehung. – jahresberichte und mitteilungen des oberrheinischen geologischen vereins, neue folge 14, 176–190. reitner, j., thiel, v., zankl, h., michaelis, w., wörheide, g. & gautret, p. (2000): organic and biogeochemical patterns in cryptic microbialites. – in: riding, r.e. & awramik, s.m. (eds): microbial sediments. springer, berlin, 149–160. riding, r. (1977a): calcifi ed plectonema (blue-green algae), a recent example of girvanella from aldabra atoll. – palaeontology, 20, 33–46. riding, r. (1977b): skeletal stromatolites. – in: flügel, e. (ed.): fossil algae, recent results and developments. springer, berlin, 57– 60. riding, r. (1991): classifi cation of microbial carbonates. – in: riding, r. (ed.): calcareous algae and stromatolites. springer, berlin, 21–51. riding, r. (1999): the term stromatolite: towards an essential defi nition. – lethaia, 32, 321–330. riding, r. (2000): microbial carbonates: the geological record of calcifi ed bacterial-algal mats and biofi lms. – sedimentology, 47 (suppl. 1), 179–214. riding, r. (2002): biofi lm architecture of phanerozoic cryptic carbonate marine veneers. – geology, 30, 31–34. riding, r. (2006): cyanobacterial calcifi cation, carbon dioxide concentrating mechanisms, and proterozoic-cambrian changes in atmospheric composition. – geobiology, 4, 299–316. riding, r. & sharma, m. (1998): late palaeoproterozoic (~1800– 1600 ma) stromatolites, cuddapah basin, southern india: cyanobacterial or other bacterial microfabrics?– precambrian res., 92, 21–35. riding, r. & voronova, l. (1982): recent freshwater oscillatoriacean analogue of the lower palaeozoic calcareous alga angulocellularia. – lethaia, 15, 105–114. roddy, h.j. (1915): concretions in streams formed by the agency of blue-green algae and related plants. – p. am. philos. soc., 54, 246– 258. rouchy, j.m. & monty, c.l. (1981): stromatolites and cryptalgal laminites associated with messinian gypsum of cyprus. – in: monty, c. (ed): phanerozoic stromatolites. springer, berlin, 155–180. rouchy, j.m. & monty, c. (2000): gypsum microbial stromatolites: neogene and modern examples. – in: riding, r.e. & awramik, s.m. (eds): microbial sediments. springer, berlin, 209–216. sami, t.t. & james, n.p. (1993): evolution of an early proterozoic foreland basin carbonate platform, lower pethei group, great slave lake, northwest canada. – sedimentology, 40, 403–430. sami, t.t. & james, n.p. (1994): peritidal carbonate platform growth and cyclicity in an early proterozoic foreland basin, upper pethei group, northwest canada. – j. sediment. res., b64, 111–131. sami, t.t. & james, n.p. (1996): synsedimentary cements as paleoproterozoic platform building blocks, pethei group, northwestern canada. – j. sediment. res., 66, 209–222. schmitt, m. (1979): the section of tiout (precambrian/cambrian boundary beds, ant-atlas, morocco): stromatolites and their biostratigraphy. – arb. paläont. inst. würzburg, 2, 188 p. (dissertation, julius-maximilians-universität, würzburg, germany). schroeder, j.h. (1972): fabrics and sequences of submarine carbonate cements in holocene bermuda cup reefs. – int. j. earth sci., 61, 708–730. semikhatov, m.a. (1978): aphebian assemblage of stromatolites: general characteristics and comparison with the riphean ones. – in: lower boundary of the riphean and stromatolites of the aphebian. trudy geol. inst. acad. nauk sssr, 312, 148–158 [in russian]. semikhatov, m.a., gebelein, c.d., cloud, p., awramik, s.m. & benmore, w.c. (1979): stromatolite morphogenesis – progress and problems. – can. jour. earth sci., 16, 992–1015. serebryakov, s.n. (1976): biotic and abiotic factors controlling the morphology of riphean stromatolites. – in: walter m.r. (ed.): stromatolites. developments in sedimentology 20. elsevier, amsterdam, 321–336. geologia croatica geologia croatica 61/2–3 102 serebryakov, s.n. & semikhatov, m.a. (1974): riphean and recent stromatolites: a comparison. – am. j. sci., 274, 556–574. sharma, m. & shukla, m. (1998): microstructure and microfabric studies of palaeoproterozoic small digitate stromatolites (ministromatolites) from the vempalle formation, cuddapah supergroup, india. – j. palaeont. soc. india, 43, 89–100. shinn, e.a., lloyd, r.m. & ginsburg, r.n. (1969): anatomy of a modern carbonate tidal-fl at, andros island, bahamas. – j. sediment. petrol., 39, 1202–1228. simonson, b.m., schubel, k.a. & hassler, s.w. (1993): carbonate sedimentology of the early precambrian hamersley group of western australia. – precambrian res., 60, 287–335. stirn, a. (1964): kalktuffvorkommen und kalktufftypen der schwäbische alb. – abhandlung zur karst und hohlenkunde, reihe e, 1–92. sumner, d.y. (1997a): carbonate precipitation and oxygen stratifi cation in late archean seawater as deduced from facies and stratigraphy of the gamohaan and frisco formations, transvaal supergroup, south africa. – am. j. sci., 297, 455–487. sumner, d.y. (1997b): late archean calcite-microbe interactions: two morphologically distinct microbial communities that affected calcite nucleation differently. – palaios, 12, 302–318. sumner, d.y. (2000): microbial vs environmental infl uences on the morphology of late archean fenestrate microbialites. – in: riding, r.e. & awramik, s.m. (eds): microbial sediments. springer, berlin, 307–314. sumner, d.y. (2002): decimeter-thick encrustations of calcite and aragonite on the sea fl oor and implications for neoarchean and neoproterozoic ocean chemistry. – in: altermann, w. & corcoran, p.l. (eds): precambrian sedimentary environments: a modern approach to ancient depositional systems. i.a.s. spec. publ. 33, 107–120. sumner, d.y. (2004): secular variations in precambrian seawater chemistry and the timing of precambrian aragonite seas and calcite seas: comment. – geology: online forum, p. e56. sumner, d.y. & grotzinger, j.p. (1996a): were kinetics of archean calcium carbonate precipitation related to oxygen concentration. – geology, 24, 119–122. sumner, d.y. & grotzinger, j.p. (1996b): herringbone calcite: petrography and environmental signifi cance. – j. sediment. res., 66, 419–429. sumner, d.y. & grotzinger, j.p. (2000): late archean aragonite precipitation: petrography, facies associations, and environmental signifi cance. – in: grotzinger, j.p. & james, n.p. (eds): carbonate sedimentation and diagenesis in the evolving precambrian world. sepm spec. publ., 67, 123–144. sumner, d.y. & grotzinger, j.p. (2004): implications for neoarchaean ocean chemistry from preimary carbonate mineralogy of the campbellrand-malmani platform, south africa. – sedimentology, 51, 1–27. swett, k. & knoll, a.h. (1985): stromatolitic bioherms and microphytolites from the late proterozoic draken conglomerate formation, spitsbergen. – precambrian res., 28, 327–347. thompson, j.b. & ferris, f.g. (1990): cyanobacterial precipitation of gypsum, calcite, and magnesite from natural alkaline lake water. – geology, 18, 995–998. thrailkill, j. (1976): speleothems. – in: walter, m.r. (ed.): stromatolites. developments in sedimentology 20, elsevier, amsterdam, 73–86. trichet, j. & défarge, c. (1995): non-biologically supported organomineralization. – bull. inst. océanogr. monaco, num. spéc. 14, 203–236. truswell, j.f. & eriksson, k.a. (1973): stromatolitic associations and their palaeo-environmental signifi cance: a re-appraisal of a lower proterozoic locality from the northen cape province, south africa. – sediment. geol., 10, 1–23. turner, e.c., james, n.p. & narbonne, g.m. (1997): growth dynamics of neoproterozoic calcimicrobial reefs, mackenzie moun tains, northwest canada. – j. sediment. res., 67, 437–450. turner, e.c., narbonne, g.m. & james, n.p. (1993): neoproterozoic reef microstructures from the little dal group, northwestern canada. – geology, 21, 259–262. turner, e.c., narbonne, g.m. & james, n.p. (2000a): framework composition of early neoproterozoic calcimicrobial reefs and associated microbialites, mackenzie mountains, n.w.t., canada. – in: grotzinger, j.p. & james, n.p. (eds): carbonate sedimentation and diagenesis in the evolving precambrian world. sepm spec. publ. 67, 179–205. turner, e.c., james, n.p. & narbonne, g.m. (2000b): taphonomic control on microstructure in early neoproterozoic reefal stromatolites and thrombolites. – palaios, 15, 87–111. visscher, p.t, reid, r.p., bebout, r.m., hoeft, s.e., macintyre, i.g. & thompson jr., j.r. (1998): formation of lithifi ed micritic laminae in modern marine stromatolites (bahamas): the role of sulfur cycling. – am. mineral., 83, 1482–1493. visscher, p.t, reid, r.p. & bebout, r.m. (2000): microscale observations of sulfate reduction: correlation of microbial activity with micritic lithifi ed laminae in modern marine stromatolites. – geology, 28, 919–922. vologdin, a.g. (1962): the oldest algae of the ussr. – academy of sciences, moscow, 656 p. [in russian]. walcott, c.d. (1912): notes on fossils from limestone of steeprock series, ontario. – geol. surv. canada mem., 28, 16–23. walcott, c.d. (1914): cambrian geology and paleontology iii. precambrian algonkian algal fl ora. – smithsonian miscellaneous collection, 64, 77–156. walter, m.r. (1972): stromatolites and the biostratigraphy of the australian precambrian and cambrian. – spec. pap. palaeontology, 11, 190 p. walter, m.r. (ed.) (1976): stromatolites. developments in sedimentology 20. elsevier, amsterdam, 790 p. walter, m.r., bauld, j. & brock, t.d. (1976): microbiology and morphogenesis of columnar stromatolites (conophyton, vacerrilla) from hot springs in yellowstone national park. – in: walter, m.r. (ed.): stromatolites. developments in sedimentology 20. elsevier, amsterdam, 273–310. warnke, k. (1995): calcifi cation processes of siliceous sponges in viséan limestones (counties sligo and leitrim, northwestern ireland). – facies, 33, 215–227. wharton, r.a., jr., (1994): stromatolitic mats in antarctic lakes. – in: bertrand-sarfati, j. & monty, c. (eds): phanerozoic stromatolites ii. kluwer, dordrecht, 53–70. whittle, g.l., kendall, c.g.st.c, dill, r.f. & rouch, l. (1993): carbonate cement fabrics displayed: a traverse across the margin of the bahamas platform near lee stocking island in the exuma cays. – marine geol., 110, 213–243. wilks, m.e. & nisbet, e.g. (1985): archaean stromatolites from the steep rock group, northwestern ontario, canada. – can. j. earth sci., 22, 792–799. geologia croaticarobert riding: abiogenic, microbial and hybrid authigenic carbonate crusts: components of precambrian stromatolites 103 winefield, p.r. (2000): development of late paleoproterozoic aragonite seafl oor cements in the mcarthur group, northern australia. – in: grotzinger, j.p. & james, n.p. (eds): carbonate sedimentation and diagenesis in the evolving precambrian world. sepm spec. publ. 67, 145–159. wright, v.p. (1989): terrestrial stromatolites and laminar calcretes; a review. – sediment. geol., 65, 1–13. young, r.b. (1932): the occurrence of stromatolitic or algal limestones in the campbell rand series, griqualand west. – transactions geological society south africa, 35, 19–36. zankl, h. (1993): the origin of high-mg-calcite microbialites in cryptic habitats of caribbean coral reefs – their dependence on light and turbulence. – facies, 29, 55–60. manuscript received july 6, 2008 revised manuscript accepted september 3, 2008 geol. croat. 49/2 335 337 1 fig. zagreb j996 absrracf note the integration of geological parameters: procedure, importance, practical value dubravko lucie 1. introduction the procedure from petroleum exploration through field development 10 production activities in any region is undoubtedly a very expensive and risky business. recent changes in the traditional organization of many oil and gas companies has been caused by several fac­ tors. tn an area of fluctuating oil and gas prices, an increased emphasis on profit margins, finding and development costs, production expenses, and the opti­ mal exploitation of producing properties have been of major imporlance. in attempt to reduce down pre­ drilling risks/costs, with the intention of production optimization, the integration of all the geological, petro­ physical and other parametcrs is obvious. carefully selected "playcrs" with special skills work together, resolving the particular problems, from the microscopic point to interwell and fieldwide scale via a depositional model and log/seismic analysis. technicaly, the first step is necessary to make the petrophysical and geolog­ ical integration of all the available, laboratory "in situ" parameters. in addition to "mechanical" propcrties (alhilali & shanmugam, 1991), the other geo­ logical disciplines (lucic & krizmanic. 1993) like sedimentology (johnson & stewart, 1987) , sequence stratigraphy (pa yton, 1977; lucic, 1995), biostrat igraphy, palaeoecology (krizmanic & pre­ mec-fucek, j 996), geochemis try etc .• also have to be takcn into accou nt for the bettcr understanding of the dynamic history ofthc rcscrvoir (vavra et al., 1991), or sourcc rock development. the results of such inte­ gration process should be used as the calibration tool for additional methods e.g. wire-line logging, seismic etc. (serra, 1985), which enable latera l correlation. in this way, with a relatively low budget a real and nat­ urally crcated object is described within a chronostrati­ graphicaly defined environment (sneider et ai., 1987), and should be prepared for the additional explo­ ration or production development. a very important aspect in such geological integra­ tion is a management philosophy. the key to the inte­ gration process is to take a company's rcspective capaina-naflaplin, laboratory dept., lovinciceva i, hr-ioooo zagreb, croatia. proceedings bilities, and apply them routinely as the team in a front linc operating mode. something like solving a puzzle of technological pieces, creating artificial intelligence by forming a synergis tic t organization (sneider, 1991). 2. synergy between geology, petrophysics and engineering the rocks are basic. the industry's technological advances con tinually provide new measurements and sensors to indirectly image the reservoir. one can lose sight of the simple fact that it is a real rock that is being described. any st udy should be based on detailed palaconto­ logical and petrographic analyses, sedi mentological descriptions of cored intervals, petrophysical analysis and detailed log analysis of the same cored wells. 3. objectives i. stratigraphic setting 2. lithofacies/petrofacies/mechanical facies definition 3. establishing thc internal geometry of the reservoir zonation of reservoir flow units discrimination of pay from non-pay intervals cvaluation of the continuity of different pay zones and of barriers to f low 4. depositional environment relationships between petrofacies and depositional environment rcscrvoir quality control (diagenesis/depositional environment) subdividing the formation into stratigraphicaly correlative units 5. recognition of litho/pet ro/mcchanical facies from the wejj logs· 6. wei! to well correlation i synergy is defined as the "action of discreet agencies so that the total effect is grater than the sum of the effects taken independen­ tly". tn the petroleum exploration and production business, synergy means that geologists, geophysicists, petroleum engineers and oth­ ers work together on a project as a team. 336 petrologists i sedimentolog1sts i paleontologists development geologist exploration i development geophysicist exploration geologist petrophys1sicts facilities engineers res ult :::: production operation optimizat ion opti ­ mized fi eld development (drilling less well s in bet­ te r places), optimi zing individual we ll production, pl anning a production fac ility designed specifically 10 the longterm requirements of the ri e ld. the s tudy demons trates ihe utili sation o f an inte­ grated palaeontological, pe trologica l, sedimentologica l and wi re line log analyses in ident ify ing the contro ls on reservoir quality at the pore level and ex tending this to the int e rwe l! and fie ld wide scal e via a depos itional model and log analysis. an interactive a pproach would have to employ eng inee rs, a geo log is t, and a petro­ physicist to "fine tunc" the model to aclual ri e ld resu lts (fig. i) 4. t ea m organization and management philosophy in the previolls chap ter some technica l de tails con­ cerni ng the integrat ion procedure were presented. i-je re are some comme nts on the sociological aspect of team­ work o rgani zat ion. the fund amen ta l worthwhile probl ems today in finding oi l arc a m ix ture of enginccring-geology-mathe­ matics-gcophysics wit h the variabl e addit ion or fin ance, gas/o il marke ting, drilling costs, eco logy e tc. conse­ quen tly it requires a large and sometimes very complex organiza tion. no genius wi ll comc a lone to solve such a problem, we have to bu ild a genius by ourse lves. what do we need? a rte r masters ( 199 1) ihe main poinls are: a. find oil come together to rind oil not only to make footage. drill a hole that can be properly evaluated and optimal­ iyeomp leled . reservotr engineers production engineers stratigraphers drilling engineers geologia cromie:. 49/2 fig. i synergislic organ isalion. b. f'reedom freedom to contribute and communicate. c. disband disband the leam when the problem is sol ved. the team bui lding is a socia l acl ivity. wha t arc the building blocks? what is necessary? i. recognition of teams (in tegrated brain power of numerous special is ts) 2. commitment from t he top (financial and technological support) 3. people (eonsislenlly high-qualily people) 4. tr ust & friendship (tru st from the management and am ongs t them­ selves) 5. contrib ute (freedom 10 colllribule) 6. communicate (rreedom to communicate) 7. ac hi evement uob sat isfact ion by achievement rather than title) 8. flexible organiza tlon ( fl exible, fluid organ iza ti on; less administ rati on) 9. participation (anyone who doesn ' t participate is out; vita l rule) i ,ll~ic: '!1ic intcgrati on ofgcoiogic;\i l'ar;l1llclcrs: procedure. importance. pi~\c ti ci\l v,liuc 337 5. conclus ion the success ful employment of task rocused team ­ wo rk and techn o logy can provide a company with a competit ive advantage in the oil and gas industry of the future . comparison of the organization or the traditio­ nal large co mpany divi s ion and the small synergistic co mpany or several foreign cxamples (sne ider , 1991; masters, 1991) was amazing. smal l synergis­ ti c tcam s found about 2 .8 timcs thc reserves at about hall' the cos t, bes idc that the developmcnt cos ts arc of course s igni fi cantly lower for thc small cr group. we have to try together to improve the hlllnin g of our exp loration -production business and become more competiti ve in the increasi ngly complex techno logica l search 1'01' oi l that we arc in vo lved in. 6. references aljiil/\lj, k.a. & shanmugam, g. ( [991 ): utili ­ ty or mechanical facies for rock classificat ion, char­ ac te ri za tion and correlalioll.tn: proceedings of the 1st archie conference, the integration of geology, gcophysics, pe trophysics and petrol eum delin ­ eation , descrip tion and managcll1 enl. aapg , 801m. joh ns on, [-1.0. & stewart, d.j. (1987): ro[ e 0 [' clastic sedimentology in the explorat ion and produc­ ti on of oil and gas in thc north sea.in: bea ­ mont, e.a. & foster , n. h. (cds.): reservoir [, properties , treatise o r pcl ro leum geology, aa pg , reprint sci'., 3, 29-44. kr[ z man [c, k. & premecfucek, v. ( 1996): jusliriability or the biostratigraphy explorations in petroleum geology. geol. croat. , 49/2, 333-334. luc[c, d & krizmanic, k. (1993): laboratorij ske tehnike i metod ika primjene rezu ltata tijekom geo­ loskog istrazivanja i razrade podzemlja. naftaplin, [4/1, [s [9, zagreb. lucic, d. ( [995 ) : sekveneijs ka strat ig ra fija novi pu tokaz u is trazivanju karbonalni h stijena na prim­ jeru srednjojadranskog podmorja.na i't apl in, 15/1, 13-22, zagreb. masters , j .a. (1991 ): teamwo rk.in : proceedings o f the 1st arch ie conference, the integ ra tion of geology, geophysics, pe trophysics and petroleum del ineation, descripl ion and management. aapg, 335-339, tulsa. payton, c.e . (cd.) ([977): seismic strati graphy­ app lications to hydroca rbon resea rch. aa pg , mem. , 26, 503 p. serr a, o. (1985 ): sedime ntary env ironments from wirel ine logs .schlumberger, spec. issue, 7-2 11. sneider , r.m. , richardson, f. [ i. , paynter, d.o. , eddy, r.e. & wyant, i.a. ( [ 987) : pre­ dicting rock geometry and continuity in pennsy lvan­ ian reservoirs, e[k city fic[d, ok[ahoma.in: bea­ mont, e.a. & foster , n. [ i. (cds.): rescrvoir ii , properti es, treati se of pe troleum geology, aa pg , reprint sci'., 4, 1-62. sneider, r.m. ([991): the economic value 0[' a syn­ e rg istic organization. tn: proceed in gs of th e 1st arch ie conference, th e integ rati o n or geo logy, geophys ics, petrophys ics and pe troleum delin ­ eation, descri ption and managemenl. aapg , 328334. vavra, c.l., sci-ieining, m.h. & kle[n , j.d. ( 1991): reservoir geology of the t ay lor sandstone in the oak hill f ield , rusk count y, texas: integra­ tion o[ petrology, sedim entol ogy and log anal ys is for dc lincl:lt ion of reservo ir quali ty in a light gas sl:lnd. in: proceedings o f the i s t archie con ference, the tnteg ration of geology, geophysics, petro­ physics and petroleum del ineat ion , description and management. aapg , [30[59. :bx gcologi;, cro:l1ic:i 49j2 geol. croat . 50/2 243·250 2 f igs. zagreb 1997 triassic deposits of hrvatsko zagorje antull simunic and alka simunic key word s: triass ic , sandstones, dolomites, lime ­ stones, c lastics, tuffs, andesi tes, basalts, j-irva tsko zagorje, croatia. abstract in the area of hrvalsko zagorjc, t riassic deposits crop-oul in the form of tccton ic emplacemen ts, formi ng the cores of all the inajor mountains. 'nlcy also underlie neogene deposi ts, as proven in nume­ rous boreholes. during the triass ic reriod , contin uous sedi mentation occurred mainly in $h:lliow marine env ironment s, though transient subsidence occurred in the anisian and lad inian epochs. in the lower triass ic, the ncmshorc clastic and carbonate sediments were deposited, which were succeeded in the middle and upper triassic by shall ow·wat cr limestoncs. the lallcr for their most par! have undergone later do lo · miti salioo. ow ing (0 rapid sub si dence during middl e ani siun and ladinian limes . sedime ntation of the fin e-grained c lastics, pelagic limestones lind chc rl.~ occurred together wi th loca l vo lcanic intru­ sions. 1. introduction geologica l research on the tri ass ic sediments 111 hrva ts ko zago rje was initi a ted by austro· hunga rian geologists in ihe middle of ihe last century. many trea­ ti ses we re publi shed on these inves tigations, the work by ha uer ( 1868), who distinguished lower triass ic sed im ents in the ivanscica and strahin scica mts., and ass igned all limestone and dolomite rocks in hrvatsko zagolj e to " i-iall stattc r und esino schichten", bei ng the mosi imponant. the resu lt s of previous inves tiga ti ons were col lated by gorjanovic>kramberger (1902, 1904a, b), inc luding his own works, and pub­ lished in the fol1n of geological maps, and explanations or the shee ts vi nica, rogateckozje and zlatar-krap­ ina. after golj anovic's works had been published, the regiona l geological investigations in the area of hrvat­ sko zagorje were terminated. some fifty years later, a new cycle of invest iga tion of the triassic deposits in hrvatsko zagorje was com­ menccd by the academic ian m. herak. coworking wilh tn stitute of geology, sachsova 2. p.o. box 268, hr· 10000 zagreb, croatia. m. malez he proved for the firs t time, using the disco­ ve ry of the alga telll/oporella !jercu/ea (sto ppanl). that ladinian deposits deve loped in the carbonate facies also exist in this area (herak & malez, 1956). sev­ e ral years la ter he describcd the lad inian sponges fou nd on the north side of ivanscica mi. , aner which he publ i­ shed a review of tri assic sed imen ts o f yugos lav ia , emphasizing the impac t of tec tonic s tages on the sedi­ mentary conditions (herak, 1960, 196 1). t hi rty years later, di viding the tectonic zones of the dinar ides and de finin g the ir northe rn limits, he inc luded hrvatsko zago rje in "s upradinari eum '" (h erak, 1986. 1991; herak et al. . 1990). other geological inves ti gati ons o j" ihc triass ic sedi ­ ments of hrvatsko zago~je were re lated mainly either to work on the sheets of the bas ic gcological maps: zag­ reb (s iki c c t a i. , 1979), varazd in (s imun ic et a i. , 1981), rogatce (an1c ic & jur1sa. 1985) ancl l vanic g rad (basch. 1983), or to some minor works with re f­ erence to specific geological problems. thesc works are referred to in the explana tio ns of the basic geolog ical map, and they will be rev iewed later in the tcxi in order to avoid repet ition. it should be emphasized tha t thi s paper rcp resents the first attempt to display the triassic system of hrva t­ sko zagorje integrally. comprehensive atten tion is paid to lesser known topics such as the relationships between specific lithostratigraphic units, as well as to geological boundaries, sedimentary conditi ons, reexa mination of stratigraphic determination of c lasti cs with vo lcanites, and corre lat ion of contcmporaneous depos it s in the wider regi on. 2. lithostratigraphi c characteristics triassic sediments foml the central parts of the maj­ ority of the zagorje mountains, where they appear in the form of tectonic emplacement s, mainly in the corcs of the neogene anticlines (fig. 1). the exception is med this paper was presented at the scientific meeting dedicated to the 80th anniversary of the life of professor milan herak, held on march 5th, 1997 in zagreb 244 n ...... d 0 , eb o.konjicina : .. ' o .' .' . .... .. ' ........ zoqreb ueologia croatica 5uri fig. 1 distribution of triassic dc­ posits in the area of hrvatsko zagorje. legend: i) study ar­ ea; 2) mostly triassic dolomi­ tes and limestones; 3) mostly triassic tuffs; 4) neogene and quaternary sedimems; 5) deep boreholes with pierced trias­ sic deposits; 6) mountains of hrvatsko zagorje: i ravna gora, 2 hum , 3 brda, 4 sv. duh, 5 zeljeznica, 6 varazdinske loplice, 7 . kost­ run, 8 kuna gora, 9 slmhin­ scica, 10 ivanscica, 11 cc­ sarsko brdo, 12 strugaca, 13 ,:1 eels vucak, 14 ljubelj, 15 hum-sagudovec, 16 zakic­ nica. vednica mt., where triassic rocks occur in a much mo­ re complicated form, most ly as the remnants of over­ thrusts (sikic et ai., 1979). furthermore, it is proven by numerous boreholes that in the greater part of hrvat­ sko zagorje triassic sediments underlie neogene car­ bonates and clastics. the mountains of hrvatsko zagorjc display a very intricate tectonic configuration, which is the reason why hardly a single tectonically quiescent area can be found to establish the integral geologic column. the given geologic column (fig. 2) is composed of partially drawn c ross sections and data assessed by geological mapping. on the basis of lithological and palaentological charac teristics, the triassic of hrvatsko zagorje is divi­ ded into three major parts. clastic and carbonate depo­ sits relate to the lower triassic, the carbonate and vol­ cano-clastic sediments belong to the middle triassic, whereas only the carbonate rocks pertain to the upper triassic. occasionally, one can arrive at more detailed division of the triassic system into eight lithostratigraphic units, but, due to the major dislocation of sedi ­ ments and scarcity of fossil findings, it is hardly feasi ­ ble over the entire area of hrvatsko zagorje. 2.1. the lower triassic (scythian) the lower triassic sediments occur on almost all mountains of hrvatsko zagorje, except fo r the kalnik and strugaca mts. their greatest exposure is on the ravna gora mt., while elsewhere they appear in the form of narrow zones, erosional remnants, or enclosed tectonic blocks. during hydrothermal research, their extension was also established beneath the surface, as they are partially drilled in krapinske toplice at a depth of 6s0-720 m, and in stubicke toplice at depths of 260390 m. due to later tectonic movements, the exposure of lower triassic clastics is irregular and unpred ictable. sometimes they are accumulated in a single place resulting in deposits several hundred metres thick, while sometimes they can be found only in traces. tntesimunic & simunic· tri·\ssic deposits of j irvatsko zagorje 24, u vi i / / vi ... triaslna hantkenl ell/plica 1= . /1/ / / permodtscus pragsoldes ~ i i i megalodus sp. a: i i i "' il. i / il. ::> -/--if f-t fu u f-t i-j ih h z ladlnella porata -j -/1-... " teulloporeua herculea f !1t+tt1-t z dlplopora annulala debuts ~ i v •••.•• uvanella lrreg ularl'i 0 '" v (f) ... +1 -f'it + ito ...j ii~ hr+~ ~ / dlplotremmtna aslrojlmbrlala (f) ~ i--f; f --4 t;i 4f -imacroporella alpina ~ anlsoporella anlslca rtf h.ff it z ~ meandrosplra dlnarlca ... « .... ....... . 0 a a , v v -. . . . . . . . . . . '" , a / vi v v v v v· •• g lomosplra densa ~ it -f-.:t +; ~ if + macroporeua aiplna f if-t-t frondlcularla woodwardi z " -i+ -fphysoporella pauctjorata a: ... / i i .... 0; ammodiscus cj (ncerius fig. 2 schematic geological ~ z ~ meandrosplra pussilla column of the triassic ... -=--:;: n . . . . . . deposits in hrvatsko " natlcella castala >= " zagolje. legend: i) mi u • . . . . . .. . . myaclles (anodonlophora) jw;saensis caceous sandstones and c 0 0 0 0 0 0 vi ~ pseudomanotls (elaraia) daral siltites; 2) shales; 3) 00-.. litie limestones; 4 lime~~~f;:r=;=lr:z::;:z:::l~~ ~~ 1~2~3tii±:rn 4l::::d 5tz:::::zj6~7~8~9~ stones; 5) bedded dolo­ mites; 6) massive dolo­ mites; 7) andesite-ba­ salts; 8) luffs; 9) cherts. nsive [olding is part icularly evident on the thrust fronts as, for example, near l ab lanovec on the medvednica mt., in the vicini ty of the road tunnel on the strahin­ scica mt., and in the crests of folds in the ravna gora mi. or at hromec village in the li ne o[ hum na sutli lepoglava belctinec. up to the present lime various opinions ex ist con­ cerning the nature of the geological boundary between lhe upper permian and lower triassic. on the sheets of the basic geological map of varaidin and rogalec, this boundary is deduced as an uninterrupted sequence, while on the sheets of zagreb and ivanic grad it appears as an eros ional unconformity. recent investiga­ tions have shown that the undisturbed relat ionship between the upper permian and lower triassic only ra re ly occurs in hrvatsko zagorje, while for the most part ihe boundary appears as an erosional unconfor­ mity. the scarce outcrops in the wes tern pail of ivanscica mr., and in the area of strahinscica me reveal that lower triassic clastics overlie the brown-red conglomerates and coarse-grained sandstones, or the so-called "groden deposits" (perm ian). the layers are mutually concordant making their appearance on the terrain as the norm al transition of permian into lowcr triassic clastics. such a boundary, regardless of the absence of angular discordance can not be considered as an unin­ terrupted sequence because in the lower triassic sand­ stones the content of terrigenous material changed as the particle size reduced, and the quantity of muscovite increased. this was caused by signifi can t palaeogeo­ graphic modifications which brought about a change in provenance of the clastic material, a reduction in relief, and longer transporlation distances. in the eastern part o f ivanscica mt. and on cesarsko brdo mt., a 1-2 m thi ck layer of grey porous dolomite sporadically appears at the boundary of palaeozoic bla­ ck shales and sandstones with overlying brow n-red werfenian (lower triassic) sediments. the occurrence of dolomite, sometimes with salt or gypsum, shows that the input of clastic material was sporadically interrupt­ ed, with emergence of a lagoon where the evaporitic 246 sediments had been formed. there is a well-known sail deposit on the northern slopes of mcdvednica mt., in siani potok (salt creek). the salt appears at the border between metamorphic rocks and lower triassic sand­ stones. ncar rude, in neighbouring samoborska gora mi., well-known deposits of gypsum can be found, whereas in the valley of the bregana brook dolomite occurs instead of gypsum, containing the upper permi­ an calcareous algae (herak & skalec. 1967). in the area of hrvatsko zagorje, the lower triassic sediments maintain the overall uniform development and can be divided into two parts: the lower (clastic) and upper (carbonate) werfenian. in the lower triassic, which can be considered as an equivalent of the lower wcrfenian sediments, the recurrent alternations of micaceous sandstones, mica si ltites, shales, marls and, more rarely, oolitic lime­ stones has been observed . thei r colour is mostly red­ brown, brought about by the content of haematite and limonite. lon g ago, the iron ore was mined in these rocks, leaving on the s lopes of medvednica mt. nume­ rous pits, remnants of smelting furnaces, and even the traces of slag at some places . sediments without the iron content are yellow, grey or greenish-grey in colour. red-brown, micaceous sandstones occur as the most extensive lithological member of the lower triassic sedi rn ent s. they are determined as sublithie arenites and quartz arcnites. the main components of sublithic areni tes are quartz, feldspars (albite and andesine) and muscovite, while quartz prevails in the quartz arenites. the sandstone cement is variable in composition: some­ times it is quartz and limonite, or haematite and limo­ nite with additional sericite, and sometimes it is calcite with a mixture of limonite. among the heavy minerals, rounded apatite and zi rcon prevail, while garnet and epidote occur more rarely. the sandstones sometimes appear schis tose as a result of the parallel orientation of foliate minerals, and they sometimes display vestiges of metamorphosis. ripple-marks and smooth laminations are common. fine-grained sandstones and silt ites are very mica­ ceous, sometim es co ntaining ferruginous substances. the bl ack and grey varieties of these are enriched in carbon. the sandstones and marls are interbedded with thin layers or lenses of oolitic limestones. the main compo­ nents arc ooids varying in size between 0.04-0.5 mm, with mixtures of non-carbonate and arenitic particles. the ooid core can be a microfossil, a fragment of mac­ rofossil or intraclast. the limestone cement is com­ posed of the fine-grained calcite wh ich envelops the ooids and fills the interstices. the main components of shale are clay, muscovite and sc ri cite, while quartz, chlorite and calcite occur rather rarely. in thc marls, the quantity of microcry­ stalline calc ite, togethcr with previously quoted compo­ nents, amounts to 65% of the rock. strat igraphic determination of the lower triassic clastics is established from the abundant fossil content geologia croatica 50(2 found in almost all the zagolje mountains. the follow ­ ing species of lamellibranchiata and gastropoda have been determined: myacites (anodontophora) jassaensis wissman, pseudomol1tis (claraia) ciarai emm­ ricl-i, and naticel/a costata (monster) (lipold, 1862; sikic et ai., 1979; simunic et ai. , 1980; anicic & jurisa, 1985; basch, 1983). the upper werfenian consists of dark-grey, tabu ­ late and thin to middle-bedded limestones that outcrop on the ravna gora ml. and in the ivanseica strahin­ seica kostrun mt. range. on other mountains their thickness is small (10-20 m) , wh ich is why they arc generally not displayed on geological maps. on the ravna gora mt., a gradual transition has been observed from the lower to the upper werfenian. in the upper levels of the lower werfcnian clast ics intercalations of the dark-grey limestones appear, which afterwards completely prevail. thi s boundary is rather interesting in a geological sense since it points to the initial deposition of carbonates which, although inter­ mittent through the anisian and ladinian, proceeded into the jurassic. the limestones along thc lower boundary can also contain mixtures of quartz and limonitic-clayey mate­ rial, while fine-grained, microsparite calcite gradually prevails in the upper levels. the following types of limestones are determined: microsparites, fossiliferous microsparites and crinoidal microsparites. freq uently there appear "schistose" or "breccia-like" textures, whi­ ch arc associated with the disposition of joints, thin vei­ ns and microstylojites, being caused by post-triassic tectonic activity. in the arca of ravna gora, the fossiliferous micro­ sparites are abundant with foraminifera, crinoid debris and mollusc shells, while intraclasts, peliets and ooids arc sparse. crinoidal limestones, specifj cally crinoidal microsparites, also frequently occur. these rocks arc formed exclusively from the crinoid sterns and forami­ nifera, while ooids, mollusc shell s and non-carbonate arenitic components arc sparse. calcareous dolomites and black shales may occur in alternation with the limestones. dolomites are thin-bed­ ded, finc-grained, and sometimes contain mixtures of clay and limonite. in the upper parts of the upper wcr­ fenian deposits, the number and thickness of dolomite layers ever incrcase up to th e absolute prevailance of dolomites at the anisian boundary. from the upper werfenian limestones of the ivans­ cica and ravna gora mts. the fo llowin g species of microfossils were determined by m. milanovic (in simunic ct ai., 1980): meandrospira pus ilia (ho), ammodiscus incertlls (d' orbigny) and glomospira sp. 2.2. the middle triassic during the middle triassic shallow-water lim e­ stones were predominantly deposited, their origin relat­ ed to a "carbonate platform". today these rocks arc for the most part dolomitised and tectonically displaced, silllllilic & si11lljllic: trial>si(.; del}()\ils or ilr\':lisko z:lgorjc though on the basis of rare fossil finds and their mutual superposition they can be divided into the anisian and ladinian series. in the middle of the anisian and ladinian epochs the fine~graincd clas tics, cherts and tuffs were deposit ­ ed, with sporad ic occu rrences of volcanic intrus ions. the origin of the c las tics and volcanites is related to the abrupt and relat ively shorl~lived periods of subsidence with s ubsequ ent recc urrcnee or sedimentation in the s hall ow~water marine basins. the anis ian dolomites and limestones form mosl of the l vansc ica strahinseica ravnu gora ~ kostrun mts. range, but they ca n also be found on the other mount ai ns (except mi. kalnik). almos t alt thcnnal wa­ ter boreholes have reached the triassic dolomites and dolomite breccias (fig. i ). up to the present, a continu~ ous sequence of sedimentation from the upper scythi an to the anisian has only been discovered on ravna gora mi. , while on the othe r mountains the said boundary is tec toni call y dislocated or concealed. a similar geolog i ~ cal cross section ncar rimske toplice in eastern slove~ nia (ramoys & anicic, 1995) proves this to be, at any rate, noi an iso lated phenomenon. dark-grey dolomites are the illost frequent and most identifiable mcmber of the lower part of thc anisian stage in ilrvatsko zago rje. fragments of crinoids can o rt en be found in these rocks , suggesting that these dolomites originated by the process of dolomitisation of the c rinoidal limcstones. this rules out any sign ificant palaeogeographic va riations having occurred at the uppe r wcrfcnian ~ lower anisian boundary. not on ly did sedi mentation of carbonates never cease bui , co j1 ~ versc ly, layers of conside rable thickness have been pro­ duced. on the bas is of chemi cal analyses it has been de te rmined that the dark dolomite colo uring der ives from an increased co nccntration of organic matter. sometimes, these rocks include the intercalations of che rt of 1111ll -cill dimensions which arc supposed to be di agenetic in origin (s im unic & sim unic, 1980). it can be observed at outcrop that dolomites abrupt ­ ly change from black to grcy, which is most probably a conseq uence of reg ressive movement s in the sedimen~ tary bas in which caused al gal limestones to be dcpos it ~ cd instead of c rinoida l ones. sedimenla ry~pelrographie anal yses have de te rmined that these do lomites be long to the middle-grained calcarcous , stromatolite and algal iypes. they have arisen by dolomiti zation of algal lime­ stones, a llowing 1'01' all possible trans itions in appear­ ance. major bodies of limestones, not affected by dolomi ­ tization , c rop oul on the ravna gora and eastern part of ivanse ica mts., but the se can also be seen in minor exposu res in other zago rjc mountains . they arc very important ror the clari fi cation of st ratigraphic relation­ sh ips, having been the only source of determinable fos~ sils. the fo llowin g spec ies of algae and foraminife ra have been determined by m. milanovic (i n simunic c t ai., 1980) : meal/drospira dil/arica kocl-lansky­ devide & panti c, g/olllospira del/sa (pantic), 247 macroporefla a/pina pia, pacel/refla hexasler (p ia ), physoporel/a pgllei/orata (gumb el). on thc northern s lopes of the ivanscica and strahin ~ seica mts. great bodies of grey and dark~grey dolomi te breccia are exposed. these originated from crushing of dolomites and their subseq uent recementing. they arc intersected by numerous joints fill ed with recrystalli zed dolomite and calcite. large slickensides, trac ing major fault s, fault zones, o r thrust pl anes, can be found in these rocks. due to their great porosity, thesc breccias have proven to be ve ry good fresh~wa t e r and the rmal water aquifers (semnicke topliee, yratno) in ihe middle anisian an abrupt change in sed imen­ tation occurred with deposition of deep-water c last ics and vol canites instead of shallow-wate r carbonates. these rocks are present in almost all the mountains or hrvatsko zagorje, having been drilled ncar konjseina at depths of 3,850-4,250 m (dragi ceyic ct ai., 1995), and ncar krapinske toplice at 550 m. the st rati ­ graphic position of these rocks was variollsly int erpret ~ ed in the works of previous authors and subsequent explanations of the basic geologica l maps, while the ir supposed age extended roughly from the palaeozoic to the lower miocene. among the scdim entary rocks, the most common arc the black and rcd shales, black and grey siltites, and rcd-brown radiolarian cherts. in addition , the grey, fin e­ grai ned limestones with radiolaria and filam e nt s, as well as luffilic limcs tones wi th radiola ri a, turfs and andes ite-basalts sporadically occur (s imunic & s im­ unic, 1980/81). great expanses 01" tuffs and bas ic ehusives arc present on the northern slopes of jvanse iea mi. , but they can al so be found on st rahinscica, kuna gora, and kostrun mts. they arc intercalated wit h dolomites, and vary in thickncss from 20-200 m. gorjanoyic-kramberg er (1904a. b) eon­ sidcred the clastics with volcanites in the area of l vans~ eiea, strahinsciea and kostrun mts. as being or palaeo­ zoic agc, while similar rocks on kuna gora ml. were class ified as an anisian "eoquina" on thc bas is of the ammonit e fossil s. salopek ( 1918) studied the co l­ lected cephalopod fauna of kuna gora mt. and came to the conc lusion that it indicated an upper anisian age. tucan (1922) supposed the andes ites and basalts on ivanseica to be olde r than "carbonife rous sla tcs" and "werfen ian schists" on the basis of the latter bein g without ev idence of contact metamorphi sm. sed imentation of the middle triassic c lastics wi th volcanites occurred suddenly, which is not easy to ex p­ lain in the face of familiar sedimentary processes. pre­ viously they werc supposed to be deposited in a eugeo­ syncline , but recently the majority of geologist s are of the opinion that ihay have arisen during the birth of a "rift va ll ey". thus, indeed , the sw ift subsidence and sediment ation of the deep~ sea deposit s can be exp la ~ ined, but it is not easy to elucidate the rapid regress ion and recurrent sedimentation or shal low-water carbon­ ates. were the "rift val ley" closed by compression, the rocks wit hin would have been compressed 100 , and .,. could certainly not be preserved. the low~ang l e thrust can a lso be infe rred w hi ch , owing to its immen sity, resembles an overlying rock mass, though it is not easy to assume it wi ll always affect the same stratigraphic level. in other words, an arrangement of strata such as this, along with pe riodic thickening or thinning of the clastics and volcanitcs, can be traced from ivanscica to kostrun mts. (about 50 km). perhaps the most accept­ able is boillot 's concept (boillot, 1983 ) whereby s im ilar phe nollle na are expla ined by subduc tion on a carbonate platform. after the subduction processes had been terminated, the entire area was uplifted with sub­ sequent recurrence of the sedimentation of the shallow­ water carbonates. light-grey, fi nc-grained , intensely sili ci fi ed tuffs, ex tending fro l11 rogatec throu gh lepoglava to vara­ zdinskc toplice. arc also included in the midd le trias­ sic (fig. 1). they are determined as vitric, crystallo-vit­ ri c, c rystallic and lithi c tuffs and tuffites. t hese arc sometimes "pierced" by the altered spili ti zed diabase and sporadica lly interbedded with quartz schists. they o ften overlie lower miocene clastics which is why they were ass igned to the lower miocene by gorja­ no vickramberg er ( 1904a), while kispatic ( 1909) never conside red these rocks as tuffs, but as fine-gra ined quartz rocks instead. even on the separate shee ts o f the bas ic geo logical map of varazdin and rogatcc these arc variolisly interpreted. more recent research has shown the presence of two types of tuffs in thi s series. earl ie r tuffs usually include in their basal part the lower triass ic deposits overlain sporadically by ani sian dolomites and limestones. in addition, they are proven to be occasionally thrusted over lower mi oce ne clastics, which made earl ier auth ors ass ign them to the lower mioce ne. later tuffs arc of the andesite-dacite typc, bcing weakly li th ifi cd and placed a t the egerian-eggenburg ian bou ndary (s imunic & pamic, 1993). therefore, there are two groups of vol­ canic rocks in thc " gorjanovic andcsitc iinc" which points to the instabili ty o f the area and a reccurrence of the volcanic activ ity. in the upper part of the anisian sed imen tation of algal limesto nes con tinued wh ich werc late r mostly dolom itised. however, in the eastern part of ivanscica mi. , on ly a few metres above the clastics, blue-gree n algae have been folind . the following speci es have been dctermined from the belski do l area by mi lanovic (in simunic et a i. , 1980): diplotremino ostrofimbriato kristan-toll­ mann, macroporella a/pina pia, anisoporel/a anisi­ co (zanin-buri) , mendrospira dinorico kochan­ sky-devide & pantic. according to the geological map and partially estab­ lished geologic columns one can suppose the total thi ckness of the ani sian deposits to be 400-500 m. herein a zone of tu ffs running from hum l1 a sutli lepoglava beletinec to varazdinske toplice must be sorted out, the thickness of which occasionally exceeds 400 m. sedimentation of shall ow-water limestones contin­ ued through the ladinian and these were late r largely dolomitiscd and recrystalli zed. thi s extensive mass of grey, fineto medium-grained dolomites infrequently contains re lic blocks of li mestones . the limestones are fine-grained . often recrystallized, and sporadically sili ­ cified. t heir occurrence is important for stra ti graphic de termination because they are the only source of the de terminable fo ssil remnant s . for the time being the ladinian sediments have been proven only in the area of ivanscica mt. the first ladinian fossils found there had been decribed by herak & malez (j 95 6) and herak (1960), but they were subsequently discovered elsewhere. the following species have been detennined by milanovic (in simunic e t a i. , 1980) : uvane llo irregularis ott, dictyocoelia mollon (monster), lodillello porow ott, teutloporello haw lea (stop­ pani), diploporo anllulata debilis pia and other. on the southwestern slopes of ivanscica mi. , a nar­ row and intermittent zone of shales, siltites and weath­ ered pyroclastics has been observed wi thin the shallow­ water carbonates. the pyroc las tics are determined as vitric and crystallo-lithic tuffs, tes tifying by their pres­ ence volcan ic activity wi th in the same basin. at the moment, the true thickness of ladinian depo­ sits remains unknown due to continuous sedimentation into the upper triassic, while both their great ext ent and intensive tec tonics did not a llow direct fi e ld mea­ surements. according to the geo log ical map and cross sect ions, the th ickness of ladinian deposits is assumed not to exceed 300 m. 2.3. the upper triassic the upper triassic deposits are most ex tens ive ly exposed in the ce ntral and eastern parts of ivan sc ica mi. , but more rare ly o n the northern slopes of kalnik mt. and in the western part of medvednica mt. the upper triassic dolomites and limestones encoun tered elsewhere in the zagorje mountains on ly occur in the form of isolated blocks. most of the upper triass ic rocks on the southwestern s lopes of medvedni ca and southern slopes of ivan sc ica mt s. rcpresent the rem­ nants of thrust faults (sikic et ai. , 1979; simunic et ai. , 198 1). due to occurrence of largely dislocated rocks, cont i­ nuity of sed imentation from the midd le to the uppe r triassic has never been proven in the field , whereas it can be assumed on the basis of the unaltered litholog i­ cal composition of the sediments. in the upper triassic, the stromatolitic, intraclastic, fineto medi um-grai ned dolomites dom inate over the algal, peloidal and. more rarely. oncoidal limestones. dolomite and calc-dolom ite breccias can be frequently found , being occasionally interbedded with dolomites. moreover, in the area of the kal nik and medvednica mis. cherts and radiolarian shales have been found , the karnian and karnian-norian age of which have been determined on the basis o f radiolaria (halamic & gorican, 1995). simunic & simunic: rriassic deposits of hrvatsko zagorjc tn the area of ihe lvanscica and kalnik mis., find­ ings of megalodonts have been known since the times of austro-hungarian geologists (foetterle, 1861/ 62), and were lat er found on a few different sites. occurrences of upper triassic fossils are abundant only on the southern slopes of strahinscica mt. the follow­ ing spec ies have been determined by milanovic (in simunic et ai. , 1980): triasina hanlkeni elliplica majzon, permodiscl/s pragosides (oberi-iauser), glol1lospira sp., trocholillg sp. and other. the most detailed geological cross section through upper triassic deposits in northwestern croatia was discovered in a quarry ncar podsused, in the northwest­ ern part of medvednica ml., but later, unfortunately, completely destroyed due to mining. for 200 metres across the site, a rh ythmic sequence from cryptocrys­ talline through microcrystalline dolomite and dolomi­ crite, to llh stromatolite and fenestral stromatolite, as well as dolomicrite was determined. investigation of thi s geological cross seclion allowed the sparse fossil assemblage to be documented, but only the forami­ nifera triasillg haf1fkeni was determined (fucek ct ai., 1995). in the area of hrvatsko zagorje, detai led division of the upper triassic stage could never have been per­ fo rmed because of dolomitisation, recrystallization, scant fossil findings, and extensive tectonic disruptions. furthermore, true thickness has not been determined, although, according to fie ld observations and represen­ tat ion on the geo logical map, it can be inferred to be approximately 250-400 m. 3, conclusion the triassic deposits form the central parts of most of the zagorje mountains, with the exception of mec!­ vednica mi., where these rocks are thrusted over younger deposits. besides, the triassic rocks also un­ derlie neogene clastics, which is proven by numerous boreholes. during triassic sedimentation was continuous, mos­ tly within shallow marine basins , whereas the intermit­ tent subsidence occured during the anisian and ladi­ nian. in the lower part of the scythian, fine-grained clastics were deposited, whereas in the upper scythian sed imentation of carbonate rocks began which, regard­ less of temporary cessations, continued into the liassic. deposition of the carbonate rocks was temporarily interrupted in the middle an isian and in the ladinian, when deep-sea clastics, cherts and pyroclastics were deposited along with sporadic intrusions of volcanites. 1n hrvatsko zagorje the existence of all the triassic series has been proven due to the fossil occurrences, but because of intensive tectonism, no single area could be found to es tabli sh the complete geological column. nevertheless, on the basis of the aforementioned char­ acterist ics, the triassic sediments of hrvatsko zagorje can be divided into eight lithostratigraphic units that 249 will be di splayed on the new geological map of the republic of croatia, scale 1 :50.000, which is currently being compiled. on thc ivanscica mi. the lower, middle and upper triassic has been proven, though the conformity is only incompletely established. it is supposed that all the series of the triassic exist on the medvednica mi., but only their lower and upper parts are proven palaeontologically. the lower and upper triassic deposits are proven on ravna gora, strah inscica, kuna gora, kostrun and cesarsko brdo mts., as well as in the hum na sutl i lepoglava beletinec varazdinskc toplice range of hills. in the area of mi. kalnik, the middle and uppcr tri­ assic was determined, whereas on strugaca mt. no fos­ sil remains were found aided the st ratigraphic determi­ nation of the grey dolomites which was the reason of their assignation to the middle triassic. 4. references anicic, b. & jurisa, m. (1985): osnovna geoloska karta sfrj, i: 100.000. tumac za list rogatcc l3368 (geology of rogatec sheet). geoloski zavod ljubljana & geoloski zavod zagrcb ( 1983), savezni geol. zavod beograd, 76 p. basch, o. (1983): osnovna geoloska karta sfrj, 1:100.000. tumac za list ivanic grad l33-8 1 (geol­ ogy of ivanic grad sheet). geoloski zavoc! zagreb (1981), savezni geol. zavod beograd, 66 p. boillot, g. (1983): geologie des marges contincn­ tales. masson, paris, 148 p. dragicevic, b. , udjbinac, z. & simunic, an. (1995): geoloska grada podzemlja hrvat skog za­ gorja. in: vlahovic, i. , velic, i. & sparica, m. (cds.): 1st croatian geological congress, opati­ ja 1995, abstracts, 30, zagreb. foetterle, f. ( 1861/62): geologische karte von croatien. jahrb. geol. reichsanl. , 12/1, (verh. 123124), wien. fucek, l., tisljar, j., sokac, b., prtoljan, b. & ostric, n. (1995): gornjotrijaski dolomiti u kamenolomu podsused.in: sikic, k. (cd.): geo­ loski vodic medvednice. institut za geo!. islraiiva­ nja i ina-industrija nafte d.d. , 41 -43, zagreb. gorjanovic-kramberger, d. (1902): geologi ­ jska prijeg ledna karta hrvatske i siavonije, 1 :75.000. tumac geologijske karte vinica, zona 20, co l. xiv.naklada kralj. zemalj. vlade, odjel za unutarnje poslove, zagreb, 30 p. gorjanovic-kramberger d. (l904a): geolo­ gijska prijegledna karta hrvatske i siavonije, 1:75:000. tumac geologijske karte rogatec-kozje. l ... u zona 21, col. xlll.~ naklada kralj. zemalj. vlade, odjel za unutarnje poslove, zagreb, 24 p. gorjanovic~kramberger, d. (1904b): geolo~ gijska prijegledna karta hrvatske i slavonije, 1:75.000. tumae geologijske karte zlatar~krapina. zona 21, co. xvi.~ naklada kralj. zemalj. vlade, odjel za unutarnje poslovc, zagreb, 42 p. halamic, j. & gorican, s. (1995): triassic radi~ olarites from mis. kalnik and medvedniea (north­ western croa tia).~ geol. croat., 4s/2, 129~ 146. hauer, f. (1868): geologische uberzic hkarte dcr osterreichischen monarchic, i :476.000. blat 6, ostlichc alpenlander.~ jahrb.geol. rcichsanst., is, 1 ~44, wien. herak, m. (1960): kreda s ofiolitima u ivanseiei (sjeverozapadna hrvatska) (kreide mit ophiolithcn in del' tvansciea (nw croatia).acta geo !. , 2,11120, zagreb. herak, m. (1961): trias dc la yougoslavie.~ geol. vjcsnik, 15/1, 303 ~31o. herak, m. (1986): a new concept of geotectonics of the dinarides.~ acta gcol., 16/1, 1 -42, zagreb. herak, m. (1991): dinaridi. mobilisticki osvrt na genezu i struktu ru (dinarides. mobilistic view of the genesis and strukture).acta geo!., 21/2,35-117, zagreb. herak, m. & malez, m. (1956): teutloporella her~ culea (stoppani) in the district of golubovec (nw croatia).~ bull. sci. cons. acad . yougosl., 2/4, 106~ 107, zagrcb. herak, m., jamicic, d., simunic, an. & buko~ y ac, j. (1990): the northern boundary oi the dinarides (sjeverna granica dinarida).acta geo!., 220/1, 5~27, zagreb. herak, m. & skalec, d. (1967): kalkalgen im perm des samoborer gcbirges (vapnenacke alge u pennu samoborskog gorja). geol vjesnik, 20, (1966), 37~39. kispatic, m. (1909): mladje eruptivno kamenje u sjcverozapadnom dijelu hrvatske.~ rad jazu , 177, 97~154, zagreb. lipold, m.y. (1862): galmei und braunkohlenberg~ bau in ivanec.lahrb. geo!. reichsanst., 12/2, 135139, wicn. licologla croatlca ju/l ramoys, a. & anicic, b. (1995): untertrias und unteranis ausbildung im misnica-tal, ostlich von rimske toplice, ostslowenien.rudarsko-meta­ lurski zbornik, 42/3-4, 143~155, ljubljana. salopek, m. (1918): monografija trijadickc eefalo~ podne [aune kuna-gore.prir. istraz. jazu, 13,2127, zagreb. sikic, k., basch, o. & simunic, an . (1979): osnovna geoloska karta sfrj, i: 100.000. tumae za list zagreb, l33~80 (geology of zagreb shect).~ institul za geol. islraz. zagrcb (1972), savezni geot zavod, beograd, 81 p. simunic, ai. & simunic, an. (1980): petrografski sastav i geneza trijaskih naslaga ivanscice, kalnika i ravne gore (hrvatsko zagorje) (petrographic com­ position and genesis of triassic deposits or ivans­ cica, kalnik and the ravna gora mountain).geol. vjesnik, 32 (1979), 243~253. simunic, ai. & simunic, an. (1980/81): dliboko~ vodni sedimenti srednjeg trijasa kostruna (zapadni dio hrvatskog zagorja) (deep walei' sediments or the middle triassic of kostrun montain (western parts of hrvatsko zagolje».vcsnik zav. geol geo­ iiz. istrai., (a), 38 ~ 39, 205~221, beograd. simunic, an. & pamic j. (1993): geology and pet~ rology of egerian-eggenburgian andcsites from (he easternmost parts of the periadriatic zone in hrvatsko zagorjc (croatia).acta geol. hungarica, 36/3, 315~330, budapest. simunic, an., pikija, m., hecimoyic, i. & sim~ unic, ai. (1981): osnovna geoloska karta sfrj, 1:100.000. tumac za list yaraidin, l33~69 (geolo~ gy of varazdin sheet).-institut za geol. istraz. zag­ reb (1981), savezni geol. zavod, beograd, 75 p. simunic, an., simunic, ai. & milanovic, m. (1980): geoloska grada tvanscice i ravne gore (geology of ml ivanscica and mt. ravna gora (northwestern croatia)). ~ geol. vjesnik, 31 (1979), 157~174. tucan, f. (1922) : starije eruptivno kamenje u sjeve~ rozapadnom dijelu hrvatske.glasnik hrv. prji'. drus., 34, 169~184, zagreb. manusgript received april 14, 1997. revised manuscript accepted november 10, 1997. palinkas.indd 93 � ab stra ct samoborska gora mts. is situated within the westernmost part of the zagorje–mid–transdanubian zone of the internal dinarides. the samoborska gora mts. predominantly consists of permian unmetamorphosed siliciclastic sediments and evaporites, overlain by lower triassic sediments. rude mineralisation is hosted by permian siliciclastic sediments, below gypsum and anhydrite strata. the central part of the deposit consists of a 1.5 km long stratabound mineralisation, grading laterally into ferruginous sandstone and protruding vertically into a gypsum–anhydrite layer. siderite–polysulphide–barite–quartz veins are located below the stratabound mineralisation. the stratiform part of the deposit is situated above the stratabound and consists of haematite layer with barite concretions and veinlets. late stage galena–barite veins overprint earlier types of mineralisation. the rude ore deposit was generated by predominantly nacl ± cacl2–h2o solutions. detrital quartz from stratiform mineralisation contains fl uid inclusions with salinities between 7 and 11 wt. % nacl equ., homogenizing between 150 °c to 230 °c. stratabound/siderite–polysulphide–barite–quartz vein type mineralisation was derived from solutions with salinities between 5 and 19 wt. % nacl equ., homogenizing between 60 °c and 160 °c, while late stage galena– barite veins were precipitated from solutions with salinities between 11 and 16 wt. % nacl equ., homogenizing between 100 °c to 140 °c. fluid inclusion bulk leachate chemistry recorded na+>mg2+>k+>ca2+>li+ and cl–>so4 2– ions. sulphur isotope composition of barites and overlying gypsum stems from permian seawater sulphate, supported by increased br– content, which follows successively the seawater evaporation line. the sulphur isotopic composition of sulphides varies between –0.2 and +12.5 ‰, as a result of thermal reduction of permian marine sulphate. ore–forming fl uids were produced by hydrothermal convective cells (refl ux brine model), and were derived primarily from permian seawater, modifi ed by evaporation and interaction with permian sedimentary rocks. rude deposits in samoborska gora mts. may be declared as a prototype of the permian siderite–polysulphide–barite deposits (products of rifting along the passive gondwana margin), in the inner dinarides, and their equivalents extending northeastward into the zagorje–mid–transdanubian zone and the gemerides, and southeastward to the hellenide–albanides. keywords: rude siderite–polysulphide–barite–haematite deposit, early intracontinental rifting, sedex, feeder zone, evaporites, shock quartz, planar deformation feature, pdfs, zagorje–mid–transdanubian zone, internal dinarides permian–polysulphide-siderite–barite– haematite deposit rude in samoborska gora mts., zagorje–mid–transdanubian zone of the internal dinarides � ladislav a. palinkaš1, sibila borojević šoštarić1, sabina strmić palinkaš1, walter prochaska2, jorge spangenberg3, stela cuna4 and †boris šinkovec5 1 faculty of science, university of zagreb, horvatovac 95, hr-10000 zagreb, croatia; (lpalinkas@geol.pmf.hr; phone: +385-1-465-971; fax: +385-1-4605-988) 2 institut für geowissenschaften, montanuniversität, peter-tunner-strasse 5, a–8700 leoben, austria 3 institute of mineralogy and geochemistry, university of lausanne, bfsh–2, ch-1015 lausanne, switzerland 4 national institute for research and development of isotopic and molecular technologies, 65–103 donath, ro-400293 cluj-napoca, romania 5 faculty of mining, geology and petroleum engineering, university of zagreb, croatia doi: 104154/gc.2010.06 geologia croatica 63/1 93–115 30 figs. 4 tabs. zagreb 2010 geologia croaticageologia croatica geologia croatica 63/1geologia croatica 94 nica mts. can be grouped into four main units. autochthon: 1) tectonized ophiolite mélange, including all lithological members, from sediments, to basic and ultrabasic igneous components, 2) palaeozoic–triassic magmatic–sedimentary complex overprinted by early cretaceous metamorphism, 3) late cretaceous–palaeocene fl ysch, and allochthon: 4) triassic and younger sequences belonging mainly to carbonate platform facies (šikić et al., 1978; 1979; basch, 1981; šikić, 1995). the autochthon of samoborska gora mts. consists only of: 1) palaeozoic unit, composed of late carboniferous dark gray schists, shales and sandstones. shallowing of the sedimentary basin evolved into a dry-land phase, followed by deposition of fi ne to coarse–grained sandstones, interlayered with conglomerates, dolostones and evaporites (herak, 1956). these deposits are unconformably overlain by an early triassic clastic–carbonate unit, followed by middle and late triassic carbonate–marl sediments, with occasional appearances of cherts; 2) cretaceous mélange is predominantly composed of basalts and diabases within shal es, graywackes, conglomerates, radiolarites and limestones of different mesozoic ages, covered by neogene sediments. the volcanics, often as basalt–spilite pillow lavas, might be products of a triassic rifting stage, and allochthon: 3) is represented by mesozoic carbonate platform lithotypes. the basic difference in geology of the samoborska gora mts. in relation to medvednica mts. geology is the absence of the palaeozoic–triassic magmatic–sedimentary complex overprinted by early cretaceous metamorphism in the form er, and the presence of ultrabasic members in the ophiolitic mélange of the latter (šikić et al., 1979; tomljenović, 2000). the common feature is the presence of siderite–polysulphide–barite–quartz deposits, at rude (samoborska gora mts.) and bistra (medvednica mts.) within the permian non– metamorphosed clastics. the deposits are confi ned to early intracontinental rifting in the northwestern sector of neotethys and were emplaced along the passive continental margin of gondwana (palinkaš, 1990; palinkaš et al., 2008). 3. mineralisation the rude siderite–polysulphide–barite–haematite ore deposit is located within the valley of gradna creek, in the village of rude, 25 km west of zagreb. the mineralisation is hosted by permian siliciclastic sediments, overlain by gypsum and anhydrite deposits (fig. 2), and consists of three epithermal ore types (low to intermediate temperature): 1) siderite–polysulphide–barite–quartz veins (fig. 3a), 2) stratabound siderite–pyrite–barite–quartz ore beds (fig. 3b), 3) and late stage barite–galena–quartz veins (fig. 3c), and two stratiform ore types, 4) stratiform haematite–barite–quartz beds (fig. 3d), and 5) gypsum and anhydrite layers (fig. 3e). 1) siderite–polysulphide–barite–quartz veins are below the stratabound siderite-barite-quartz ore bodies on the eastern side of the gradna valley (fig. 2) the sulphide veins cut the palaeozoic sandstones (fig. 3a). the veins are most 1. introduction the study focuses on the genesis of siderite–polysulphide– barite–haematite mineralisation of rude, samoborska gora mts., supported by geological observation, fl uid chemistry, and isotope composition of sulphides and sulphates. siderite –polysulphide–barite–quartz deposits (spbq) of the samoborska gora, trgovska gora, and petrova gora mts. are remarkably comparable in geology, mineralogy, geochemistry of fl uids and nature of metal sources. spbq deposits can be well correlated with similar spbq deposits hosted within non–metamorphosed units of the internal dinarides. these include ljubija (nw bosnia), those in the zagorje–mid– transdanubian zone, rudabanya (northernmost hungary, lower triassic), siderite–magnesite deposits in the gemerides (rudnyani, nižna slana, jelšava and others), and siderite deposits in the eastern alps (prochaska & henjeskunst, 2007; radvanec et al., 2004; palinkaš et al., 2008; strmić palinkaš et al., 2009). the spbq deposits of the samoborska gora, trgovska gora and petrova gora mts. were described by jurković (1958, 1959, 1960, 1961, 1962); jurković & durn (1988) and šinkovec (1971). the deposits have a variable appearance, epigenetic veins, stratabound and stratiform characteristics. replacement ore is present where the carboniferous carbonates are the host rocks (trgovska gora mts. and ljubija deposit). according to palin kaš (1985, 1988, 1990); palinkaš et al. (2003, 2008); borojević šoštarić (2004); borojević šoštarić et al. (2009), these deposits were formed by sub-terrestrial hydrothermal convective cells (sensu hardie, 1990), or the refl ux brine model (sensu leach et al., 2005), along the passive continental margin, during the permian early intracontinental rifting. sulphur isotopes point to the dominant contribution of the permian evaporitic sea water, as an ore– forming fl uid, modifi ed by interaction with the host rocks. it rules out a carboniferous distal volcano–exhalative genetical model (jurković, 1988), and linkage with the alpine type stratabound epigenetic pb–zn sulphide deposits, (e.g. mežica–bleiberg types in the alps), as argued for by lead isotopes (köppel, 1983; palinkaš, 1985). they also differ remarkably in sulphate isotope composition from the middle triassic dinaridic deposits, as do their prominent representatives at vareš (sedex) and idrija (epigenetic hydrothermal and sedex), (palinkaš, 1985, 1988, 1990; palinkaš et al., 2003, 2008). 2. geological setting the samoborska gora and medvednica mts. represents the westernmost part of the zagorje mid–transdanubian zone (zmtz), (sensu pamić & tomljenović, 1998; tomlje nović, 2002) or the sava composite unit (sensu haas et al., 2000; figs. 1a, b). units in the zmtz show alpine and dinaridic characteristics, including elements of both the external and internal dinarides. the zmtz is fl anked between two prominent fault zones, the periadriatic–balaton and the zagreb–zemplin lineament systems. the mountains are composed of palaeozoic, mesozoic–palaeogene and neogene formations. tectonostratigraphic units of the medvedpalinkaš et al.: permian–polysulphide-siderite–barite–haematite deposit rude in samoborska gora mts... geologia croatica 95 in the kokel and sv. trojstvo corridors, a massive siderite bed together with ferruginous sandstones, represents the stratabound ore, formed by infi ltration of hydrothermal solutions through the footwall sandstones, and partly through the overlying evaporite beds (figs. 2 and 4). mineralisation consists predominantly of coarse–grained siderite and quartz aggregates, and minor pyrite, mica and rutile. siderite mineralisation is underlain by iron–rich sandstones intercalated with 5–20 cm thick layers of clays, marl clays, cherts and siderite. the upper part of the siderite body is represented by iron rich and iron poor gray sandstones with clay intercalations. quartz pervasively replaces siderite in these ores (fig. 3b). widespread silicifi cation, and irregular veining, and in places the anastomosing appearance of quartz aggregates, suggests a hydrothermal origin, as evidenced by fl uid inclusion studies (presented in the forthcoming paragraph) rather than diagenetic recrystallization of silica. commonly cms to dms in thickness, but they can reach up to 3 m in some places (šinkovec, 1971). veins predate, are contemporaneous with, and postdate formation of the stratiform–stratabound mineralisation. the vertical extent of the vein–type mineralisation is not more than 40 to 50 m. quartz and pyrite, are severely fractured, crushed and brecciated in the veins. however, aggregates of marcasite, pyrite and chalcopyrite, in contrast, show little ductile deformation, due to compensation of the strain by the softer parts of the parageneses. the major vein mineral is siderite, which precipitated earlier than quartz, sulphides and barite. 2) the stratabound siderite–pyrite–barite–quartz ore consists of an iron ore layer extending more than 1.5 km in the ne–sw direction. the central part of the deposit is composed of a yellow–brownish siderite ore body, 180 m long, 80 m wide and up to 8 m thick (average 3–4 m) which dips 25–35° toward the nw (fig. 2; šinkovec, 1971). fi gu re 1: overview of the major tectonic units of the zagorje mid–transdanubian zone, with geological sketch map of samoborska gora mts. and the location of the rude mineralisation (pamić & tom ljenović, 1998; tomljenović, 2002). a b geologia croatica 63/1geologia croatica 96 fi gu re 2: simplifi ed cross–section through the rude ore deposit. the principle ore types are: siderite–polysulphide (cu, pb, zn)–barite–quartz veins (designated on the fi gure as cu–fe ore veins), stratabound siderite–barite–quartz beds (on the fi gure as siderite), stratiform haematite–barite beds (on the fi gure haematite), and gypsum and anhydrite beds (on the fi gure as evaporites). old mining corridors were drawn as trapezoidal openings. the cross– section is in realistic scale based on the mining maps (šinkovec, 1971). fi gu re 3: structure of the principal ore types: a) content of the vein mineralisation: siderite (sd)–chalcopyrite (cpy)–pyrite (py)–barite (brt)–quartz (qtz); b) stratabound massive siderite (sd) with irregular patches of quartz (qtz); c) successive growth of galena (gn) and barite (brt) in the late stage veins; d) stratiform beds of haematite (hm) with detrital, heavily fractured quartz (qtz); e) gypsum (gp) with highly contorted bends, coloured with iron and manganese oxy–hydroxides (hm). a b c d e palinkaš et al.: permian–polysulphide-siderite–barite–haematite deposit rude in samoborska gora mts... geologia croatica 97 a change to more oxidizing condition can be deciphered by the presence of barite (fig. 4) at sites 6, 10, 11, and 12. pyrite is highly cataclased (fig. 6; site 10). the massive siderite ore layer laterally grades into the ferruginous sandstone. the siderite cement of the sandstone is gradually converted to a haematitic one, by a process synchronous with mineral precipitation. it is evidenced by the intimate intergrowth of quartz grains and haematitic cement, as well as the absence of traces of box-work or any other supergenic texture, even on a microscopic scale (sites 9 and 13). in contrast to simultaneous precipitation, elsewhere, siderite ore underwent oxidation and attained a micro–brecciated structure. the exposed siderite sandstones are oxidized by supergenic conditions and quartz grains are coated by colloform goethite, forming garlands, with a cockade ore texture, while a box–work texture developed in the oxidized massive siderite (figs. 18, 19, 20). 3) late stage, low-intermediate temperature, galena–barite veins consisting predominantly of galena, barite and minor sphalerite and quartz, cut upper palaeozoic sandstones these are the youngest veins in the rude ore deposit, and thus they overprint earlier types of mineralisation (fig. 3c). maximum thickness is 20–30 cm, and the veins usually end in a network of horstail veinlets. 4) the stratiform haematite–barite–quartz ore (fig. 3d) consists of small lenticular ore bodies, 5 to 30 m in length, and 1 to 4 m thick. vertically and laterally this kind of ore passes gradually into ferruginous sandstones with 8 to 30 wt. % iron content. the old mining site and outcrops of the haematite–barite–quartz ore are exposed at the klassenbruch locality, at the upper riverhead of the gradna stream. the stratiform haematite–barite–quartz ore has a homogenous structure (fig. 3d). the major ore mineral is haematite. in places, barite veinlets, no longer than 4 mm, and barite concretions, mm-cm in size, accompany the major mineral. quartz is ubiquitous, and sometimes rhythmically alternates with haematite. haematite conglomerates, with rounded and angular quartz clasts, are matrix– and clast– supported (from a micro– to cm– scale). the origin of quartz is ambiguous, either chemogenic or detrital (figs. 3d, 21, 22). the problem of detrital quartz in the stratiform ore type was questioned and indicated in the original paper of šinkovec (1971). detrital quartz is marked by a mosaic suture along the grain boundaries (figs. 21, 22). the shape and sharp contours of the grains, attest little or no transport. quartz agglomerations, show conical organization of grains, resembling shattered cones. the quartz grains are severely frac tured, radially or across the grain boundaries. jigsaw-fi t structures are common (fig. 21). the deformation features, no wider than 0.1–1 μm, cut across the grains as planar or bent lamellae, closely spaced, following crystallographic planes, usually decorated by fl uid and/or mineral inclusions as a result of annealing and healing (french, 1998). plastic deformations are easily observed in the form of undulatory extinction on rotation of the stage of the polarizing microscope, which follows the same inclusion-bearing tracks visible in plane polarized light (fig. 22). they are referred to as possible shock metamorphic phenomena, induced by meteorite impact at the p/t boundary (kieffer, 1971; kieffer et al., 1976; grieve et al., 1996; french, 1998). there are two possibilities for how quartz entered the ore and sedimentary environment of evaporation. one is being washed into the basin from an already impacted paleorelief, or introduced as an instantaneous impact load into the soft, iron rich mud (the future stratiform ore). filling of fi ne jigsaw-fi t fractures with haematitic cement, suggests the latter mechanism. more detailed elaboration requires further fi gu re 4: sketch map of the sv. trojstvo and kokel pits with old mining works (šinkovec, mining report, 1954). the numbers and spots mark the sites examined by microscopy. stratabound siderite–barite–polysulphide ore, below a gypsum layer, consists of massive yellow–brownish siderite, with pyrite, intensively silicifi ed and partly oxidized (sites, 1., 2., 3., 4., 5., 7.). the reducing conditions during precipitation gradually changed to more oxidizing, evidenced by the presence of barite (sites, 6., 10., 11. and 12.). stratabound ore in the form of ferruginous quartz sandstones, with siderite cement, partly hematized, microbrecciated, is the lateral extension of the siderite layer. siderite–sulphide veins intersect or cross the siderite layer. geologia croatica 63/1geologia croatica 98 research efforts, and the rude deposits may be an interesting object for the international audience regarding p/t bound ary phenomena. 5) the gypsum and anhydrite layers, heavily contorted with red–green–gray–white bands are part of the ore series and are present in the hanging wall of the ore body together with dark dolomite, chert and fi ne and coarse grained siliciclastics (šinkovec, 1971, fig. 3e). the sulphur isotope values suggest their permian age mimicking the secular variation of the standard permian sea water. a wide scatter of δ34s values in some gypsum specimens, however, indicates a signifi cant contribution of an extraneous source of sulphate ions (šiftar, 1989), as does a high content of lead. 4. materials and methods of study the samples for ore petrography were prepared by a standard procedure. cut ore samples were embedded into plastic rings 2–4 cm in diameter, greased, ground (using 120, 240, 400, 600, 800, 1200 mesh quartz powders) and polished (using 6, 3, 1 and 1/2 μm diamond and aluminium powders). a zeiss axioplan microscope equipped with a digital camera at etvös lorand university, budapest was used to determine ore minerals, paragenetic successions and distinct textures. microthermometric measurements were performed on 0.3–0.5 mm thick wafers of quartz on a leitz–wetzlar microscope with objectives p25/0.50 for freezing and um 32/0.30 for heating runs by a chaixmeca cooling and heating stage, operating between –180 and +600 °c. a linkam thms 600 stage was mounted on the olympus bx 51 microscope using 10x and 50x olympus long–working distance objective lenses for visible light. two synthetic fl uid inclusion standards (syn flinc; pure h2o, mixed h2o–co2), were used to calibrate the equipment. the precision of the system was ±2.0 °c for the homogenisation temperature, and ±0.2 °c in the temperature range between –60 and +10 °c. primary fl uid inclusions were determined on the base of their petrography, according to procedure described by roedder (1984) and sheperd et al. (1985). fluid inclusions were measured in: i) quartz associated with stratabound siderite–pyrite–barite–quartz mineralisation; ii) detrital quartz associated with stratiform mineralisation; and iii) barite associated with late stage galena–barite vein mineralisation. the salinity was calculated from ice and hydrohalite melting temperatures using the fluids computer program developed by bakker (2003), and according to the procedure described by naden (1996). isochores were calculated using the computer program isoc (bakker, 2003), from the equation of state by zhang & frantz (1987), and corrected for the volumetric properties of quartz. the bulk ion compositions of trapped fl uids were analysed by ion chromatography at montanuniversität leoben by the technique modifi ed after bottrell et al. (1988). a dionex dx–500 system was used for analyses of halogens. cations were analyzed in the aliquots of the same solution using standard atomic absorption spectrometry. the bulk crush–leachate analysis was performed on: i) quartz, haematite and barite associated with stratiform mineralisation; ii) quartz and siderite associated with stratabound mineralisation; and iii) barite and galena associated with late stage galena–barite vein mineralisation. the sulphur isotope compositions of sulphide (n=9) and barite (n=2) samples were determined at the institute of mineralogy and geochemistry at the university of lausanne using the carlo erba 1108 elemental analyzer (ea), connected to the thermo fischer scientifi c thermoquest/finnigan mat delta s irms (ea/irms). barite and gypsum samples were collected from i) stratiform mineralisation. pyrite, chalcopyrite, sphalerite, galena and barite were sampled from ii) siderite –polysulphide–barite–quartz vein mineralisation, and galena and barite from iii) late stage galena–barite vein mine ralisation. the isotope values are reported relative to the vienna– fi gu re 5: ore petrography with photomicrographs: a) coarse grained euhedral siderite i (sd i), with patches of pyrite ii (py ii), accompanied by cogenetic quartz ii (qtz ii) and followed by idiomorphic to hypidiomorphic marcasite (mrc) and fi ne grained subhedral siderite ii (sd ii). plain polarized light; b) polars crossed. the photo shows marcasite (mrc) with expressive anisotropic eff ects and pyrite ii. because the rate of direct nucleation of fes2 is insignifi cant in slightly acidic solutions below 300 °c, most of the pyrites and marcasites in hydrothermal ores form via the conversion of an fes precursor. marcasite can form in excess of 300°c and it can persist on a geological time scale only below 160°c. it has repercussion on the assessment of metamorphic grade of the autochtonous palaeozoic–mesozoic formation of samoborska gora mts., which has not been registered yet. 5a 5b palinkaš et al.: permian–polysulphide-siderite–barite–haematite deposit rude in samoborska gora mts... geologia croatica 99 canyon diablo troilite standard (v–cdt). the reproducibility, assessed by replicate analyses of the laboratory standard (pyrite, working value = +6.1 ‰; synthetic mercury sulphide, working value = +15.5 ‰; barium sulphate, working value = +12.5 ‰ δ34s) was better than 0.2 ‰. additional sulphur isotope compositions of sulphide (n=4) and barite (n=2) were determined at the national institute for research and development of isotopic and molecular technologies, cluj–napoca, romania. major, trace elements and ree in one sample of gypsum from stratiform mineralisation are determined by xrf and icp-ms at the bundesanstalt für geowissenschaften und rohstoffe in hannover. 5. petrography microscopy of the hydrothermal ore samples from the stratabound and vein type mineralisations determined the following primary minerals: siderite, quartz, pyrite, marcasite, greigite (melnikovite), chalcopyrite, sphalerite, galena, tetrahedrite, linnaeite, barite and chlorite. secondary minerals are: bornite, chalcocite, covellite, cuprite, and goethite (šinkovec, 1971). there are two generations of siderite. siderite i (sd i) is a coarse grained and forms euhedral to subhedral crystals (figs. 5a, 6, 7), often with annealing effects, with an approximate 120° interfacial angle. sd i is the major constituent of the vein and stratabound mineralisation, growing simultaneously with quartz i (qtz i) and pyrite i (py i) which is often cataclased (fig. 6). siderite ii (sd ii) is fi ne grained, usually euhedral and is associated with marcasite (mrc) and pyrite ii (py ii) (figs. 5a, b). as the rate of direct nucleation of fes2 is insignifi cant in slightly acidic solutions below 300°c, most of pyrite and marcasite in hydrothermal ores form via conversion of an fes precursor (schoonen & barnes, 1991). the pyrite to marcasite ratio from the sulphidation reactions is strongly dependent on ph. marcasite is the predominant product below ph 5 at 25°c, whereas pyrite is dominant in neut ral and alkaline solutions (murowchick & barnes, 1986). the same trend is observed at higher temperatures. however, although marcasite can form at temperatures in excess of 300°c, it can only persist on a geological time scale below 160°c (rising, 1973). it has previously unrecognized repercussions for assessment of the metamorphic grade of the autochthonous palaeozoic–mesozoic formation of the samoborska gora mts. quartz, beside siderite, is the most abundant mineral in the vein–type mineralisation. there are three generations of quartz: quartz i (qtz i) is cogenetic with siderite i (fig. 6). quartz ii (qtz ii) pervasively infi lls the fractures in siderite i, coprecipitating with pyrite ii. (figs. 3, 9a, b). quartz iii (qtz iii) is a product of widespread silicifi cation and coexists with all other sulphide minerals and barite (figs. 11a, b). fi gu re 6: coarse euhedral grains of siderite i (sd i), quartz i (qtz i), and pyrite i (py i). the pyrite is highly cataclased. plain polarised light. fi gu re 7: coarse subhedral grains of siderite i (sd i), with cogenetic euhedral pyrite i (py i), and later chalcopyrite (cpy) within inter–granular space. plain polarised light. fi gu re 8: a veinlet of cataclased and idiomorphic pyrite ii (py ii), embedded in the quartz ii (qtz ii). the silicifi ed siderite host was pervasively penetrated by copper rich solutions. chalcopyrite (cpy) resorbed pyrite, producing corroded, granular and rounded interfaces. the pyrite faces, embedded in the quartz stayed perfectly unaff ected by advancing replacement. plain polarised light. 6 7 8 geologia croatica 63/1geologia croatica 100 fi gu re 9: a) growth zoning; unobstructed zonal growth of pyrite i (py i) was gradually retarded by the simultaneous precipitation of quartz ii (qtz ii), which converted growth of pyrite into sectorial growth. plain polarised light; b) the sectorial texture allowed easy penetration of the copper rich solution, through a sieve-like assemblage of quartz and pyrite, and replacement of pyrite grains by chalcopyrite. replacement of pyrite proceeded by galena (upper right corner). plain polarised light. fi gu re 10: a) cataclastic pyrite ii (py ii), and marcasite (mrc) minutely disintegrated, and cemented with interstitial quartz ii (qtz), underwent massive replacement by chalcopyrite (cpy). predominantly brittle cataclasis of pyrite and marcasite grains, gradually changed to ductile deformation observed at the right corner of the photo. plain polarised light; b) advanced stage of pyrite replacement by chalcopyrite. the quartz ii (qtz ii) and pyrite ii (py ii) remain as relics of the former veinlet. pyrite severely cataclasted with crystal faces entirely rounded. plain polarised light. fi gu re 11: a) crustifi cation texture. siderite host crosscut by a symmetrical, crustifi ed veinlet showing successive inward precipitation of minerals, from the open fi ssure walls: siderite ii (sd ii) – quartz iii (qtz iii) – pyrite ii (py ii) – sphalerite (sph) – barite (brt). central part of the veinlet is fi lled with barite. plain polarised light; b) the same microphoto. crossed polars. 11a 11b 10a 10b 9a 9b palinkaš et al.: permian–polysulphide-siderite–barite–haematite deposit rude in samoborska gora mts... geologia croatica 101 marcasite; a fi ne grained aggregates of marcasite usually follows pyrite ii, and mark a slight change in the ph of the hydrothermal fl uid (figs. 5a, b). greigite (melnikovite) forms colloform spherulites, in places with garland texture (figs. 12a, b) and represents a late stage phase, however, predating galena and barite. below 300°c pyrite and marcasite form via an fes precursor (schoonen & barnes, 1991). chalcopyrite (cpy) rarely develops idiomorphically, but regularly replaces pyrite and marcasite or just infi lls the fractured grains (figs. 7, 10, 13). sphalerite (sph) is rare and is associated with barite (brt) and galena (gn) (figs. 11a, b). tetrahedrite (tet) post–dates and replaces pyrite, likewise chalcopyrite. it occurs before galena but has not been observed as having been replaced by it (fig. 14). galena (gn) is the youngest member of the paragenesis. it replaces pyrite and chalcopyrite effi ciently (figs. 12a, 13, 15), or infi lls intergranular spaces in the siderite–quartz host, forming a disseminated style of mineralisation (figs.16, 17). linnaeite (ln) is mostly euhedral, regularly embedded in chalcopyrite or occurs as individual grains (fig. 16). barite (brt) is the youngest mineral phase in the veins, infi lling inter–granular spaces induced by fractures (figs. 11a, b). in the area of klassenbruch, at the end of the gradna valley, it forms 10 to 20 cm thick barite–galena (±pyrite, quartz) veins cutting the host sandstones. fi gu re 12: a) greigite or melnikovite (grg) forms colloform globular textures, with spheruloids and garlands consisting of radial aggregates. it growths over diff erent nucleation seed cores, usually quartz ii (qtz ii). galena (gn) post–date greigite and partly or completely replaces it. plain polarised light; b) detailed image of the greigite globular texture. the zonal texture consists of bends, with random, radial or crustifi ed arrangement of aggregate elements. in the center is a quartz grain, serving as a nucleation site. the greigite probably developed over a fes precursor, gradually converting to pyrite at the outer rims of the globule. the globule is dissected by a galena veinlet, with clear sign of resorption of iron sulphide, and partially infi lled by galena. plain polarised light. figure 13: the host, coarse grained siderite (sd i), experienced several successive replacement events: fi rst silicifi cation and pyritization (qtz ii, py ii), then copper metasomatism, and resorbption of pyrite grains, while the galena (gn) stage is the last one. the cleavage pits in galena are post–depositional features. plain polarised light. figure 14: a hypidiomorphic grain of tetrahedrite (tet) resorbed a pyrite (py ii) grain. the next precipitating phase was galena which penetrated the siderite host, but did not aff ect the trahedrite grain boundary. plain polarised light. 12a 12b 13 14 geologia croatica 63/1geologia croatica 102 6. results 6.1. fluid inclusion study 1) quartz associated with stratabound mineralisation contains the following fl uid inclusion types with different degree of fi lling (palinkaš et al., 2003; borojević šoštarić, 2004): i) primary, liquid–rich inclusions, occasionally containing anisotropic daughter mineral, predominates greatly (l+v±sa), ii) pseudosecondary, metastable, liquid rich inclusions, sometimes with anisotropic daughter mineral (l±v±sa). since the vapor bubble develops after cooling runs, the meta-stability might be induced by ice extension. iii) rare vapor rich inclusions (v+l±sa), (figs. 23e, f). inclusions are spherical and irregular in shape, and range in size between 5 and 20 µm. during freezing, the following melting sequence was observed (in the presence of a vapour figure 15: atoll texture; resorption of euhedral pyrite by galena in quartz veinlet. the host is siderite i (sd i). at the bottom of the atoll–pyrite a tiny grain of pyrite is almost completely replaced. plain polarised light. figure 16: corona texture; idiomorphic crystals of pyrite (py ii) and linnaeite (ln) in the quartz (qtz ii) veinlet, are hosted between walls of coarse crystalline siderite i (sd i). at the bottom of the large galena grain (gn) a linnaeite grain (ln) is replaced by a shapeless aggregate. an idiomorphic crystal of linnaeite, however, persisted to keep a euhedral shape, but a rejuvenated galena veinlet, cut the linnaeite grain diagonally along the former veinlet path, and embraced the linnaeite crystal, forming a corona– like galena rim. plain polarised light. figure 17: siderite i (sd i) host experienced pervasive silicifi cation and pyritization (py ii). galena (gn) precipitated next, infi lling inter–granular spaces and producing disseminated galena mineralisation. curved cleavage pits have developed as a result of post–precipitation deformation. galena replaces all former sulphides. pyrite ii highly corroded. plain polarised light. figure 18, 19: ferruginous sandstone with siderite cement, oxidized to goethite (gt), which forms colloform rims around quartz grains (qtz) in the form of garlands making cockade textures. plain polarised light. 15 17 16 18 19 palinkaš et al.: permian–polysulphide-siderite–barite–haematite deposit rude in samoborska gora mts... geologia croatica 103 phase), i + hy + a → i + hy + a +le → i + hy + l → i +l →l, where i = ice, hy = hydrohalite, a = antarcticite, le = eutectic liquid and l = liquid. first melting (te) in a predominant number of liquid– vapour inclusions was observed between –65 °c and –45 °c, indicating the presence of divalent cations in inclusion liquids (ca2+, mg2+; crawford, 1981; davis et al., 1990). hydrohalite melting (tm hyd), was observed at temperatures between –50.0 °c to –23.5 °c. ice melting temperatures (tm ice) are from –15.5 °c to –3.2 °c. homogenisation to a liquid phase (th) occurred at temperatures between 56 °c and 158 °c. higher homogenisation temperatures, between 263 °c and 286 °c, were observed only in two inclusions bulk composition was calculated by the melting temperature of ice and hydrohalite. salinity of fl uid inclusions varies between 0.3 to 7.5 mass % nacl + 4.3 to 14.5 mass % cacl2, with a mass ratio of nacl/(nacl+cacl2) ranging from 0.07 to 0.76, and the total salinity ranges from 5.3 to 19.2 wt. % nacl equ. several vapour rich inclusions showed high salinity (17.9 to 18.9 wt. % nacl equ.) and very high homogenisation temperatures (between 352 °c to 449 °c) to the vapour state (figs. 24a, c, d). the inclusion behaviour is interpreted as a result of leakage. 2) the following fl uid inclusion types were found in barite associated with late stage galena–barite vein mineralisation: i) primary, metastable liquid rich inclusions (l±v), ii) pseudo-secondary liquid inclusions (l). inclusions with very small sizes (1–3 µm), occurring in clusters within healed fractures, are interpreted as pseudosecondary (roedder, 1984, figs. 23g, h, i). the last melting of ice was registered at temperatures from –12.2 °c to –7.8 °c. the homogenisation to liquid occurs at temperatures between 102 °c and 140 °c. the total salinity of fl uid inclusions was estimated to be between 11.5 and 16.2 wt. % nacl equ. (table 1, figs. 24b, c). 3) fluid inclusions in detrital quartz associated with stratiform type of mineralisation detrital quartz intergrown with haematite was separated from haematite–barite–quartz samples (fig. 3 d) from the sedimentary part of the rude deposit and the following types of fl uid inclusion were observed in them: i) secondary, metastable liquid rich inclusions (l±v), ii) secondary liquid inclusion (l), (figs. 21, 22, 23a, b, c, d). microthermometric measurements were performed only on inclusions that nucleated vapour bubble after cooling runs. due to the very small size of the inclusions (1–4 µm), during cryometric measurements, only the last melting of ice (tm ice) was registered at temperatures from –7.5 °c to –1.1 °c (table 1). the homogenisation to liquid (th) occurred at temperatures between 150 and 231 °c. the total salinity of fl uid inclusions is between 7.2 and 11.1 wt.% nacl equ. (table 1; figs. 24b, c). high temperature of homogenisation (th), with salinities between 7.2 and 11.1 wt. % nacl equ. would suggest an figure 20: box–work texture of goethite (gt) developed after oxidation of massive siderite cement. plain polarised light. figure 21: detrital quartz in the stratiform haematite beds, has developed mosaic suture joints. planar deformation features (pdfs) cross the grain boundaries. jigsaw–fi t feature on the central grain postdate the pdfs. plain polarised light. figure 22: pdfs in detrital quartz are decorated by solid and fl uid inclusions visible under high magnifi cation only. 20 21 22 geologia croatica 63/1geologia croatica 104 table 1: microthermometric data grouped according to the inclusion types in quartz from stratabound siderite-barite-quartz mineralisation, detrital quartz associated with stratiform mineralisation, and in barite from the late stage galena–barite veins. quartz, stratabound/vein type ore fi type f te (oc) tm hyd (oc) tm ice (oc) th (oc) s (wt.%nacl equ.) ρ (g/cm3) molality wt.% nacl wt.% cacl2 nacl/nacl+cacl2 l+v 0.95 –65.0 –50.2 –10.1 122.5 14.1 1.040 2.807 1.0 13.8 0.07 l+v 0.90 –40.8 –12.5 115.0 16.5 1.060 3.388 2.0 14.0 0.13 l+v 0.90 –49.0 –44.0 –11.1 112.0 15.1 1.056 3.053 1.5 14.5 0.09 l+v 0.95 –48.8 –45.3 –10.8 132.5 14.8 1.038 2.980 1.3 13.8 0.08 l+v 0.95 –27.4 –7.4 263.5 0.878 2.112 5.5 5.8 0.49 l+v 0.95 –26.8 –9.6 158.0 13.6 1.017 2.682 7.5 6.0 0.56 l+v 0.98 –6.8 132.8 10.2 1.006 1.952 l+v 0.90 –6.1 286.0 0.833 1.762 l+v 0.95 –6.1 9.3 l+v 0.98 –27.0 –6.0 9.2 5.3 4.3 0.55 l+v 0.98 –27.0 –5.7 8.8 5.0 4.3 0.54 l+v 0.98 –27.0 –5.7 8.8 5.0 4.3 0.54 l+v 0.95 –48.0 –6.2 124.0 9.5 1.007 1.789 0.5 9.8 0.05 l+v 0.98 –5.8 114.4 8.9 1.011 1.680 l+v 0.98 –3.8 109.0 6.1 0.996 1.120 l+v 0.98 –3.2 137.4 5.3 0.969 0.947 l+v 0.98 111.8 l+v 0.98 –45.0 –34.0 –5.0 112.4 7.9 1.005 1.458 2.0 6.8 0.23 l+v 0.95 –62.2 –38.0 –5.7 139.0 8.8 0.991 1.653 1.0 8.8 0.10 l+v 0.95 –61.0 –36.2 –5.2 137.5 8.1 0.998 1.514 1.0 8.0 0.11 l+v 0.95 –60.7 –38.5 –5.2 126.5 8.1 0.997 1.514 0.8 8.8 0.08 l+v 0.98 –62.5 –49.1 –11.2 114.1 15.2 1.054 3.078 0.8 15.0 0.05 l+v 0.95 –62.5 –33.5 –6.9 10.4 2.5 8.0 0.24 l+v 0.98 –58.1 –38.0 –4.4 112.0 7.0 1.000 1.290 0.8 6.3 0.11 l+v 0.98 –57.6 –38.5 –4.4 110.3 7.0 1.001 1.290 0.3 6.3 0.04 l+v 0.95 –66.5 –4.7 7.4 l+v 0.95 –47.5 –23.5 –6.2 9.5 7.3 2.3 0.76 l+v 0.85 –52.0 –27.1 –6.3 9.6 5.3 4.5 0.54 l+v 0.98 –53.0 –31.3 –13.1 107.4 17.1 1.073 3.528 5.5 4.5 0.55 l+v 0.95 –55.5 –29.6 –15.5 19.2 4.0 14.3 0.22 l+v 0.98 –36.2 –5.2 120.4 8.1 1.000 1.514 1.8 7.3 0.19 l+v 0.98 –58.8 –38.5 –5.2 121.8 0.8 8.8 0.08 l+v 0.95 148.8 l+v 0.95 122.0 l+v+sa 0.98 125.6 l+v+sa 0.95 –58.7 –38.5 –4.8 7.6 0.8 7.5 0.09 v+l 0.15 –46.2 –31.5 –14.8 18.6 0.842 3.914 5.8 12.0 0.32 v+l 0.15 –32.0 –14.0 17.9 0.697 3.734 5.3 12.3 0.30 v+l 0.25 –31.5 –15.0 18.8 0.821 3.959 6.0 12.5 0.32 l±v 0.98 –56.0 –33.2 –8.5 78.3 12.3 1.059 2.401 3.5 9.0 0.28 l±v 0.98 –45.0 –34.0 –5.1 97.0 8.0 1.016 1.486 2.0 7.0 0.22 l±v 0.98 –62.2 –36.2 –5.1 56.0 8.0 1.040 1.486 1.8 7.5 0.19 l±v 0.95 –9.7 96.0 13.7 l±v 0.95 –9.4 94.0 13.3 l±v 0.98 –51.2 –30.1 –4.5 83.6 7.2 1.019 1.318 2.3 4.0 0.36 l±v 0.98 –54.5 –32.4 –9.2 81.0 13.1 1.064 2.580 l±v –28.8 –6.1 97.0 9.4 1.025 1.762 l±v –28.8 –5.2 86.0 8.1 1.024 1.514 l±v –55.0 –30.6 –5.5 90.0 8.5 1.024 1.597 l±v –55.0 –29.8 –5.1 102.0 8.0 1.013 1.486 palinkaš et al.: permian–polysulphide-siderite–barite–haematite deposit rude in samoborska gora mts... geologia croatica 105 unrealistic pressure of fl uids originating in a shallow depositional environment. it suggests another origin of fl uid inclusions, as well as their resemblance to pdfs. 6.2. bulk crush–leach analysis the bulk crush-leach analysis was undertaken on the fl uid inclusions in anticipation that the primary inclusions were the predominant group, as attested to by fl uid inclusion (fi), microscopy. detrital quartz in the stratiform ore, however, contains mostly secondary fis, following the deformation features, not wider than 0.1–1μm, cross-cutting the grains as planar or bent lamellae. 1) samples associated with stratabound/vein sulphide mineralisation data obtained in quartz and siderite from the vein type siderite–polysulphide–barite–quartz mineralisation show dominant na+ and mg2+ cations, followed by k+ and ca2+. the dominant anion is cl– (table 2). the data confi rmed the presence of divalent mg2+ and ca2+ cations within fl uids, predicted by cryometry. the mass balance shows an excess of cations (q+/q– from 2.4 to 8.2), similar to the samples from the stratiform part of the deposit. 2) samples associated with late stage galena–barite veins barite and galena were analyzed from the late stage galena–barite vein mineralisation. the dominant cations are na+ and mg2+, while the dominant anion is chlorine within barite, and sulphate within galena. the mass balance (q+/q–) ranges from 0.8 to 1.4 (na+>mg2+>k+>ca2+>li+, table 2). late stage barite–galena veins were precipitated from moderate salinity–low temperature fl uids (salinity between 11.5 and 16.2 wt. % nacl equ., th between 102 °c and 140 °c). 3) samples associated with stratiform mineralisation the bulk crush–leach analysis was performed on detrital quartz, haematite and barite associated with the haematite mineralisation. calculated ion ratios reveal the presence of predominantly na–mg–ca–k chloride solutions. the amount of so4 2– is increased in haematite samples (ratio cl–/so4 2–, from 0.1 to 0.4). leachate of the haematite samples confi rms a mg–k–ca–na sulphate rich solution. the mass balance (q+/q–) ranges from 1.0 to 7.1. several samples show an excess of cations (up to 9.6), attributed to a possible high co3 2– and/or hco3 – concentration within bulk fl uids (due to the onset of siderite precipitation), which were not measured during the procedure (table 2). 6.3. sulphur isotopes 1) siderite–polysulphide–barite–quartz veins fifteen sulphide samples from the siderite–polysulphide– barite–quartz veins were analyzed. their isotopic compositions range between –0.2 and +12.5 ‰ v–cdt. pyrite varies between –0.2 and +11.1 ‰, chalcopyrite between –0.2 and +1.2 ‰, galena between +1.7 and +7.3 ‰ and sphalerite from +11.3 to +12.5 ‰. values increased from chalcopyrite towards galena and sphalerite (fig. 26, table 3). 2) stratiform mineralisation the δ34s values of sulphates (gypsum and barite) in the stratiform mineralisation span between +3.2 and +13.6 ‰ v–cdt (fig. 26). 3) late stage galena–barite vein type mineralisation two pairs of barite and galena samples were analyzed from the late stage galena–barite vein type mineralisation. isotopic values vary from +1.7 to +4.6 ‰ for galena and between +5.8 and +8.7 ‰ for barite samples (fig. 26). quartz, stratiform ore fi type f te (oc) tm hyd (oc) tm ice (oc) th (oc) s (wt.%nacl equ.) ρ (g/cm3) molality wt.% nacl wt.% cacl2 nacl/nacl+cacl2 l±v 0.98 73.0 l±v 0.95 –7.5 191.0 11.1 2.135 l±v 0.98 155.0 9.2 l±v 0.98 –1.1 155.0 9.2 0.959 0.333 l±v 0.98 150.0 9.2 l±v 0.98 –6.1 9.3 1.762 l±v 0.95 –4.5 231.0 7.2 0.890 1.318 barite, late brt–gn veins fi type f te (oc) tm hyd (oc) tm ice (oc) th (oc) s (wt.%nacl equ.) ρ (g/cm3) molality wt.% nacl wt.% cacl2 nacl/nacl+cacl2 l±v 0.98 –12.2 102.0 16.2 1.059 3.316 l±v 0.98 –10.3 122.0 14.3 1.029 2.856 l±v 0.98 –7.8 108.0 11.5 1.018 2.216 l±v 0.98 –9.0 138.0 12.9 1.008 2.529 l±v 0.98 –9.0 128.0 12.9 1.015 2.529 l±v 0.98 –10.0 140.0 14.0 1.015 2.782 l±v 0.98 –9.0 117.0 12.9 1.022 2.529 table 1: continued geologia croatica 63/1geologia croatica 106 figure 23: a, b, c, d, e, f, g) photomicrographs of fl uid inclusion (fis) in: 23a, b) quartz associated with stratiform haematite mineralisation. high temperature of homogenisation and salinities indicate an unrealistic pressure of fl uids originating in a shallow depositional environment. it suggests another origin of fl uid inclusions, as well as their resemblance to pdfs. 23c, d) quartz associated with stratabound side rite–barite–quartz mineralisation; shows trails of secondary, liquid rich fis. 23e, f, g) quartz associated with late stage galena–barite veins with trails of pseudo-secondary, liquid rich fis, in addition to the primary, liquid rich fis. a b c d e f g palinkaš et al.: permian–polysulphide-siderite–barite–haematite deposit rude in samoborska gora mts... geologia croatica 107 figure 24: chemical and microthermometric data of studied fl uid inclusions: a) temperature of eutecticum (te), melting of hydrohalite (tm hyd), melting of ice (tm ice) in fis of quartz from stratabound ore; b) temperature of melting of ice (tm ice) in quartz from the late stage galena–barite veins, and detrital quartz from the stratiform mineralisation; c) salinity vs. temperature of homogenisation (th) in quartz from stratabound ore, detrital quartz (pdfs) in stratiform mineralisation, and barite in late stage galena–barite veins; d) three component diagram h2o–nacl–cacl2 of melting of the last solid phase (ice). table 2: bulk crush–leachate data of siderite, barite, haematite and quartz from stratiform, stratabound and late stage galena–barite veins from rude. sample no. mineral location li+ (µmol/l) na+ (µmol/l) k+ (µmol/l) mg2+ (µmol/l) ca2+ (µmol/l) cl– (µmol/l) i– (µmol/l) br– (µmol/l) so4 2– (µmol/l) q+/ q– k+/ na+ (br–/cl–) *1000 so4 2–/ cl– s3/b quartz stratiform ore 0.12 113.92 14.71 96.32 6.72 83.36 1.90 0.30 15.93 2.85 0.13 3.65 0.19 s6/b quartz stratiform ore 0.18 102.99 14.71 94.09 402.49 88.33 1.68 0.44 12.31 9.66 0.14 5.03 0.14 s5/a barite stratiform ore 0.29 176.51 14.46 92.08 96.01 169.42 0.68 0.47 177.90 1.08 0.08 2.78 1.05 s7/b barite stratiform ore 0.33 110.48 11.06 93.07 26.49 111.08 1.97 0.57 55.07 1.61 0.10 5.13 0.50 s6/a haematite stratiform ore 0.41 44.73 123.81 82.29 1.95 21.11 3.55 71.02 2.02 2.77 3.36 s5/b haematite stratiform ore 0.91 41.86 71.97 110.43 470.20 26.96 2.87 74.76 7.11 1.72 2.77 s7/a haematite stratiform ore 0.80 23.36 60.06 99.98 28.45 7.96 2.36 74.62 2.14 2.57 9.38 s3/a haematite stratiform ore 0.33 51.06 62.95 82.29 24.68 22.32 2.58 52.79 2.52 1.23 2.37 s9/b quartz stratabound/ vein type ore 0.54 83.46 34.84 91.92 1.95 118.19 1.33 0.39 3.07 2.43 0.42 3.30 0.03 77a quartz stratabound/ vein type ore 0.24 74.03 24.07 90.63 1.29 82.68 1.71 0.32 6.17 2.91 0.33 3.85 0.07 s9/a siderite stratabound/ vein type ore 0.37 117.76 16.86 364.84 30.33 112.29 1.79 0.37 21.06 5.91 0.14 3.32 0.19 s10 siderite stratabound/ vein type ore 0.35 113.42 11.17 414.60 145.41 119.86 2.75 0.51 14.06 8.23 0.10 4.29 0.12 s8/b barite late ba-gn veins 0.37 214.88 13.54 91.46 5.46 193.75 1.39 0.49 56.09 1.37 0.06 2.52 0.29 s8/a galena late ba-gn veins 0.47 71.11 18.55 195.11 15.19 40.06 4.33 278.07 0.85 0.26 6.94 a b c d geologia croatica 63/1geologia croatica 108 6.4. geochemistry of a selected gypsum sample major elements (xrf, %), trace elements (icp-ms, ppm) and ree (icp-ms, ppm) of the selected gypsum sample from the stratiform mineralisation are presented in table 4. 7. discussion fluid inclusion data indicate differences in precipitation conditions for the stratiform and stratabound/ vein types of mineralisation (fig. 24c). the vein/stratabound mineralisation precipitated from fl uids with highly variable salinities (between 5.3 to 19.2 wt. % nacl equ.), and homogenisation temperatures between 56 °c and 158 °c (fig. 24c). late stage barite–galena veins precipitated from moderate salinity–low temperature fl uids (salinity between 11.5 and 16.2 wt. % nacl equ., and th between 102 °c and 140 °c. all measured salinities are increased relative to seawater, and the predominant portion of salinities corresponds to the composition of seawater that passed the gypsum and anhydrite precipitation point (figs. 24c, 25a, b). at some point, meteoric water entered into the system, causing dilution down to 5.3 wt. % nacl equ. the intrusion of meteoric water is a plausible explanation for coexistence between low salinity and a high br–/cl– ratio. fresh water with low concentrations of br– and cl– would have not affected their ratio but would have decreased the salinity. the chemistry of the late stage galena-barite vein changed to become more sodic in comparison to the stratiform ore which shows an expressive calcic character. the bromine/chlorine concentration ratio in quartz and barite leachates corresponds to 6.5–10.5 % of recent seawater evaporation. some part of the samples follow a seawater evaporation trend (set) to a high percentage of seawater evaporation (figs. 25a, b). the br/cl ratios demonstrate clustering of data between 15 and 35 % of seawater evaporation, but the high excursion of k/na ratios, exceeding 2 to 3 times the evaporitic concentration, is probably due to hydrothermal water/rock interactions (mccaffrey et al., 1987). ore forming fl uids underwent different degrees of evaporation, whereas a maximum degree of 35 % (according to br/cl ratios) indicates that brines locally passed the halite saturation point. these is in disagreement with the obfigure 25: composition of fl uids obtained from bulk crush/leachate ionic chromatography on barite, and detrital quartz from stratiform mineralisation, siderite and quartz from stratabound mineralisation and late stage galena–barite veins from rude: a) k/na vs. br/cl; b) k/na vs. so4/cl. evaporation trend of sea water after mccaffery et al., 1987; composition of permian seawater after horita et al., 1991. table 3: sulphur isotope values (δ34s, ‰) of sulphides and sulphates. sample no. mineralisation type mineral δ34s (‰) reference sg 1 gypsum strata gypsum 13.4 šiftar, 1989 sg 2 gypsum strata gypsum 13.6 šiftar, 1989 sg 3 gypsum strata gypsum 13.4 šiftar, 1989 sg 4 gypsum strata gypsum 10.8 šiftar, 1989 sg 5 gypsum strata gypsum 11.8 šiftar, 1989 sg 6 gypsum strata gypsum 10.5 šiftar, 1989 sg 7 gypsum strata gypsum 6.7 šiftar, 1989 sg 8 gypsum strata gypsum 3.2 šiftar, 1989 sg 9 gypsum strata gypsum 7.2 šiftar, 1989 sg 10 gypsum strata gypsum 6.2 šiftar, 1989 sg 11 gypsum strata gypsum 3.6 šiftar, 1989 sg 12 gypsum strata gypsum 8.4 šiftar, 1989 sg 13 gypsum strata gypsum 9.6 šiftar, 1989 sg 18 gypsum strata gypsum 11.1 this study sg 14 stratiform (haematite) gypsum 7.1 šiftar, 1989 sg 100 stratiform (haematite) barite 6.0 this study sg 15 stratabound/vein type* barite 11.6 šiftar, 1989 sg 16 stratabound/vein type* galena 3.0 šiftar, 1989 sg 104 stratabound/vein type* galena 7.3 this study sg 306-1 stratabound/vein type* pyrite 1.2 this study sg 304-1 stratabound/vein type* pyrite 1.1 this study sg 105 stratabound/vein type* pyrite –0.2 this study sg 301-2 stratabound/vein type* pyrite 9.9 this study sg 303-2 stratabound/vein type* pyrite 11.1 this study sg 304-2 stratabound/vein type* chalcopyrite 0.6 this study sg 306-2 stratabound/vein type* chalcopyrite 1.2 this study sg 17 stratabound/vein type* chalcopyrite 0.6 šiftar, 1989 sg 103 stratabound/vein type* chalcopyrite –0.2 this study sg 303-1 stratabound/vein type* sphalerite 12.5 this study sg 305-1 stratabound/vein type* sphalerite 11.3 this study sg 102 late brt-gn veins barite 5.8 this study sg 302-2 late brt-gn veins barite 8.7 this study sg101 late brt-gn veins galena 1.7 this study sg 302-1 late brt-gn veins galena 4.6 this study * quartz-polymetallic-siderite palinkaš et al.: permian–polysulphide-siderite–barite–haematite deposit rude in samoborska gora mts... geologia croatica 109 served fl uid salinities (max. 20 wt. % nacl equ.; e.g. undersaturated solution) and the existence of gypsum–anhydrite strata precipitated at 3.8–10.6 % of seawater evaporation. undersaturation to 20 wt. % nacl equ. or lower values of salinity were achieved by intrusion of meteoric water, with preservation of the high br/cl ratio. enrichment of sulphate (so4 2–/cl– ratio) is interpreted as the contribution of an extraneous source, which might have been oxidation of sulphide ions brought by hydrotherms, or from the host black shale by discharge of organically bounded sulphur or dissolution of sedimentary pyrite. oxidation of sulphide ions is evidenced in lowering of δ34s values in evaporites to +3 ‰. as a corollary, the dominant portion of fl uid was evaporated seawater, which temporarily did pass the halite precipitation point, and was modifi ed by evolved hydrothermal water and intrusion of meteoric water. the result was spoiling of the set line, by raising k/na and increasing the so4 2–/ cl– ratio of the fl uids. detrital quartz in the stratiform mineralisation had a puzzling habit, not corresponding to the common sedimentary origin. the uncommon but ubiquitous jigsaw–fi t structure of the detrital quartz, as well as planar deformation features across the quartz grains, pdfs, (kieffer et al., 1976; figs. 21; 22), provide evidence of two distinctive episodes during formation of the stratiform ore. the fi rst one, responsible for the trails of liquid and solid inclusions across the chert aggregates, is a shock phenomenon (pdfs, high th, 150–231 °c, and higher cl– concentration; figs. 21, 22, 24c). the second is sedimentation of massive haematite ore accompanied by barite, documented by their higher sulphate content (ion chromatography data, table 2), and incorporation of detrital quartz. according to šiftar (1989), the δ34s values of overlying gypsum from samoborska gora mts. are between +3.2 and +13.6 ‰ (fig. 26, table 3). most of the values (between +9 and +11 ‰) fall within the range of permian marine sulphates (claypool et al., 1980). lower values, between +3 and +7 ‰, are controlled by oxidation of the ascending ore forming fl uids, rich in sulphide species. increased values (up to +13.5 ‰) are interpreted as representing deposition of gypsum from the ascending sulphate already modifi ed by the thermochemical reduction of seawater which produced isotopic light sulphides and fractionated sulphates, heavier than those of the permian evaporitic water. these data overlaps with the δ34s value of sulphates in the barite from the stratiform mineralisation (+6.0 ‰), indicating the strong infl uence of the permian seawater sulphate, slightly modifi ed by sulphate formed by oxidation of hydrothermal sulphide. isotopic composition of sulphides from the vein mineralisation varies between –0.2 and +12.5 ‰ (fig. 26). a general trend of increasing isotopic values toward the late stage of mineralisation is observed (chalcopyrite < galena < sphalerite). maximum values of sulphide overlap with the values within overlying gypsum strata, proposing progressive thermochemical reduction, to completion, of the permian seawater sulphate. sulphides did seemingly precipitate under non–equilibrium conditions. the virtual non–equilibrium between sulphate and sulphide within the ore forming fl uid, and increasing trend of sulphide isotopes, is a result of successive precipitation from malcopyrite to sphalerite, with a gradual rise in sulphide isotope composition. pyrite shows figure 26: sulphur isotope data of cu–fe–pb–zn sulphides, barite and overlying gypsum in relation to permian sea water sulphates, for explanation see text (claypool et al., 1980). figure 27. the composition of the sulphur source for the late galena–barite veins was determined on the δ34sbarite/galena vs. δ34sbarite–galena plot. ore forming fl uid from which barite and galena precipitated had δ34sσs value of +6.2 ‰, and the ratio sulphate/sulphide rso4/h2s = 0.5, is determined by the slope of the line δ34sgalena vs. δ34sbarite–galena. geologia croatica 63/1geologia croatica 110 scatter of values in responds to precipitation from the earliest to the latest phases, as py i, py ii and py iii. the successions are clearly observed by ore microscopy, and progressive replacement stages (figs. 4 to 20, ohmoto & rye, 1979; ohmoto & lasaga, 1982). the composition of the sulphur source for the late galena–barite veins was determined from the isotopic values of galena and barite plotted on the δ34sbarite/galena vs. δ34sbarite– galena plot. ore forming fl uid from which barite and galena precipitated had an δ34sσs value of +6.2 ‰ (fig. 27). the ratio sulphate;sulphide, r so4/h2s = 0.5, was determined by the slope of the line δ34sgalena vs. δ34sbarite–galena. the sample of gypsum collected at the old hameatite mining site of klassenbruch has a value of +11.1 δ34s, which approximates to the well known negative peak on the curve of secular variation of permian sea water. the gypsum sample, on the other hand, has an unusually high lead (258 ppm), ba (534 ppm), v (3.4 ppm), ni (3.4), and cr (2.1) content (table 4), which speaks in favour of the contribution of metal rich brines, issuing intermittently into the evaporitic ponds. it was already evidenced by the existence of low sulphate isotope values in some gypsum samples (šiftar, 1989). high pb (534 ppm) and the relatively low content of zn (31.5 ppm) and cu (2.1 ppm) is due to the low mobility of pbso4, and dissipation of the other two ore metals, which are mobile in a cl– and so4 2rich environment. concentrations of ree are highly enriched relative to standard ocean water (sow) by a factor 105 to 106 (martin & withfield, (1983; fig. 28). the fl at, ree diagram, normalized to sow, supports the open marine origin of evaporating water, with little or no infl uence from potential dry land run–off (playa et al., 2007). lack of a negative ce/ce* anomaly and positive eu/eu* is further evidence of hydrothermal input into the evaporitic ponds. figure 28: ree in a gypsum sample from the klassenbruch haematite mining site, normalized to the standard sea water (martin & whitfield, 1983), and phanerozoic greywacke (taylor & mclen nan, 1985). the sea water is also normalized to the greywacke (analyses were undertaken in the bundesanstalt, hannover, by v. marchig). table 4: geochemistry of a selected gypsum sample: a) major elements (xrf, %); b) trace elements (icp-ms, ppm), sulphur isotope (δ34s, ‰); and c) ree (icp-ms, ppm). a) major elements (xrf, %) sio2 tio2 al2o3 fe2o3 mno mgo cao na2o k2o p2o5 so3 cl f loi summ 0.55 0.022 0.33 0.12 0.01 0.26 31.73 0.1 0.06 0.02 44.59 0.004 0.258 21.7 99.76 b) trace elements (icp-ms, ppm), sulfur isotope (δ34s ‰) ba zn pb cu cr mn ni sr ti v δ34s (‰) 534.0 31.5 258.0 2.1 2.7 17.4 3.4 891.0 57.7 3.4 11.1 c) ree (icp-ms, ppm) la ce pr nd sm eu gd tb dy ho er tm yb lu 0.580 1.200 0.150 0.570 0.100 0.074 0.093 0.016 0.092 0.018 0.050 0.007 0.058 0.009 palinkaš et al.: permian–polysulphide-siderite–barite–haematite deposit rude in samoborska gora mts... geologia croatica 111 lead isotope values obtained on galena from siderite– polysulphide–barite–quartz deposits of samoborska gora mts., trgovska gora mts. and ljubija, yield coherent model ages of 275, 285 and 280 ma respectively, by use of isochrones on the doe–zartman (1979) multistage growth curves (palinkaš, 1985; 1988). the pb–isotope evolution diagram with growth curves, (broken curve, μ = 9.56; fig. 29), represents (according to doe & stacey, 1974), the evolution of average crustal lead. the 207pb/204pb – 206pb/204pb values of the three deposits are marked on the plot and occupy the area between orogen, mantle and lower crust. the pb–zn deposits in triassic host rocks, bleiberg–kreuth, raibl, mežica, salafossa, including pb-zn deposit sv. jakob on medvednica, fall in the area marked by the broken line, designating the upper crustal reservoir (köppel, 1983; zartman & heines, 1988). one can distinguish two lead provinces, the inner dinarides with siderite–polysulphide–barite–quartz deposits, including rude, and a younger one with pb–zn deposits in carbonates like bleiberg and mežica, within the pre-existing triassic carbonate platform. the lead incorporated in galena of the two distinctly different ore types, originated from the basement greywackes, rich in feldspars (bearer of the common lead) by interaction with mineralizing fl uids. the radiogenic pb–rich source for the upper palaeozoic deposits, related to the rifting processes, is placed as shallow, affected by sub–terrestrial hydrothermal cells, fl ashed by heated evaporitic sea water. in contrast, ore forming fl uids for the triassic pb–zn deposits are deep seated brines, remobilized from deeper parts of the gondwana basement, with older but more radiogenic lead. the genetic model of the rude ore deposit had been proposed by šinkovec (1971) supported by detailed underground and surface geological mapping. the model relies on the geosyncline concept, and fi eld observations, and suggests the major physical processes engaged in the ore formation. the research presented here, sheds more light on the geochemistry of chemical processes, introducing global tectonic elements in order to establish the model and to answer the unresolved questions regarding tectonic environment, thermal regime, and the source of the metal and sulphur. the upper permian and the p/t boundary, was a transition time between the early intracontinental and advanced rifting stages in the formation of neotethys, as marked by thermal doming and extensional tectonics. dry land facies, evaporite ponds, a disturbed thermal regime in the incipient rifts, due to rifting magmatism, created favourable ore forming conditions for hydrothermal ore deposits (sedex) with a well developed feeder zone in the subterrestrial level. hydrothermal convective cells along the passive continental margin of gondwana, demarcating the future opening of the neotethys, produced numerous siderite-barite-polysulphide deposits in the alps, dinarides, hellenides and albanides. fig. 30 depicts a genetic model with basic physico-chemical processes, which governed the ore formation. the rude ore deposit is a sedex (volcano-sedimentary) hydrothermal deposit with a genetically linked feeder zone below the stratiform and stratabound ore bodies. the rifting tectonic regime, comprised thermal disturbance, caus ed by wide-spread magmatic activity, and reaching paroxysm in the middle triassic. while the global lateral extension developed deep water rift basins, and subsequent jurassic oceanization, the early rifting phenomena, including the rude mineral deposit faded gradually, and their products were covered by the stable mesozoic carbonate platform compiled of mostly carbonate sediments. the convective hydrothermal cell, forced by volcanism, as dues ex machine, (wide-spread but not recorded within the deposit itself), generated ore bearing fl uids. the special chemistry of the fl uid was comfigure 29: lead isotope evolution diagram with growth curves according to doe & stacey (1974). the curve represents the evolution of the average crustal lead, with an area discriminated for the morb basalts, red sea sediments and modern pelagic sediments. doe & zartman (1979) growth curves are construct ed for the discrete lead reservoirs, in the upper and lower crust and mantle. lead isotope data of permian siderite deposits from the trgovska gora mts., ljubija and samoborska gora mts. are distinctly separate from the middle triassic pb-zn deposits in the carbonates (mežica, bleiberg, salafossa, and sv. jakob, medvednica mts.), between the lead growth curves of orogen and mantle (lower crust out of the plot). geologia croatica 63/1geologia croatica 112 posed of evaporitic brines and meteoric water which sank from the surface into the sub-terrestrial environment and interacted with the sedimentary host rocks. the physico-chemical change of surfi cial waters includes heating, alteration of redox-potential and ph, leaching of sedimentary sulphur and dispersed metals, while upgrading into the ore forming concentration. precipitation of ore minerals started on the way to the surface in the feeder zone, within the porous sediment below the evaporitic pond, forming stratabound ore bodies. at the same time the mineralized water issued into the pond and coprecipitated with evaporites as stratiform ore. the impact shock must have been an interregnum event if one ever existed in the ore forming period. 8. conclusion the rude deposit in the samoborska gora mts. is hosted by permian non–metamorphosed siliciclastic sediments and eva porates, and composed of stratiform haematite–barite ore, stratabound/vein siderite–polysulphide–barite–quartz mineralisation, and late stage galena–barite veins. comparative study, of all types of mineralisation, provided a relevant basis for convincing genetic model. ore forming fl uids were formed by a convective hydrothermal cell over thermal anomalies (hardie, 1990), caused by wide-spread rifting magmatism (not recorded within the ore deposit itself). residual evaporitic brines, derived primarily from the permian seawater, were involved and modifi ed by interaction with the late palaeozoic sedimentary sequence (leach et al., 2005). the following evidence and data support the genetic model: sulphur isotope composition of overlying gypsum involves permian seawater sulphate. the sample of gypsum collected at the old haematite mining site of klassenbruch has a value of +11.1 δ34s, what approximates to the well known negative peak on the curve of secular variation of sulphur isotopes in the permian sea water. a wide variation of sulphate isotope values in gypsum, colored by pinkish and brownish hues, from light 3.2 to heavy 13.6 δ34s ‰, (a hanging-wall above the stratabound mineralisation), is explained by the introduction of extraneous sulphate by hydrothermal water into the evaporitic ponds. the light sulphate was formed by oxidation of hydrothermal sulphide ions. the heavy isotope ratio was generated by opposite process, reduction of sulphate, which might have been inorganic or organic in origin, and fractionation between sulphide/sulphate. this data overlaps with the δ34s values of sulphates in the barite from the stratiform mineralisation, indicating the strong infl uence of the permian seawater sulphate, slightly modifi ed by sulphate formed by oxidation of hydrothermal sulphide. the vein/stratabound mineralisation precipitated from fl uids with highly variable salinities (between 5.3 to 19.2 naci equ. wt. %). homogenisation temperatures of fl uid inclusions,wich encapsulated ore forming fl uids, is between 56 °c and 158 °c. figure 30: the fi gure depicts a genetic model with basic physico-chemical processes which governed the ore formation. the rude ore deposit is a sedex (volcano-sedimentary) hydrothermal deposit with genetically linked feeder zone below the stratiform and stratabound ore bodies. the rifting tectonic regime, followed by thermal disturbance, created a subsurface convective circulation of hot brines over thermal anomalies, as dues ex machine, generated ore bearing fl uids. the fl uid chemistry was derived from that of evaporitic brines and meteoric water which sank from the surface into the sub-terrestrial environment below, and interacted with the sedimentary host rocks. physico-chemical changes of surfi cial waters include heating, alteration of the redox-potential and ph, leaching of sedimentary sulphur and dispersed metals, upgrading into the ore forming concentration. precipitation of ore minerals began on the way to the surface in the feeder zone, within the porous sediment below the evaporitic pond, forming stratabound ore bodies. the mineralized water issued into the pond and coprecipitated with evaporites as stratiform ore. palinkaš et al.: permian–polysulphide-siderite–barite–haematite deposit rude in samoborska gora mts... geologia croatica 113 late stage barite–galena veins precipitated from moderate salinity–low temperature fl uid (salinity between 11.5 and 16.2 nacl equ. wt.%), which were trapped in fl uid inclusions displaying homogenisation temperature between 102 °c and 140 °c. ore forming fl uid, which precipitated barite and galena, had an δ34sσs value of +6.2 ‰, and the ratio sulphate/ sulphide r so4/h2s = 0.5. fluid inclusions bulk leachate chemistry recorded the presence of na+, mg2+, k+, ca2+, li+ and cl– and so4 2– ions in the fl uids. the stratiform type of mineralisation precipitated from predominantly na–mg–ca–k chloride solutions. the amount of so4 2– is increased in haematite samples, due to fi nely dispersed barite probably (ratio so4 2–/cl– from 0.1 to 0.4). leachate of the haematite samples confi rms mg–k–ca–na sulphate rich solution. the uncommon but ubiquitous jigsaw–fi t structure of the detrital quartz, (mostly chert in origin), as well as planar deformation features across the quartz grains, pdfs, (kieffer et al., 1976; figs. 21; 22), provides evidence for a possible shock episode induced by meteorite impact at the p/t boundary, during formation of the stratiform mineralisation. isotopic composition of sulphides from the vein mineralisation varies between –0.2 and +12.5 ‰. the sulphur isotopic composition is interpreted as a product of the thermochemical reduction of permian marine sulphate. the general trend of increasing isotopic values toward the late stage of mineralisation is as follows: chalcopyrite < galena < sphalerite. the maximum value of sulphur isotopes in sphalerite (+12.5 ‰) overlaps with the values of the overlaying gypsum strata, proposing progressive thermochemical reduction to the completion, of the permian seawater sulphate. lead isotope values obtained on galena from samoborska gora, trgovska gora and ljubija siderite–polysulphide– barite–quartz deposits yield coherent model ages, 275, 285 and 280 ma respectively, by using isochrones on the doe– zartman (1979) multistage growth curves (palinkaš, 1985; 1988). siderite–polysulphide–barite–quartz deposits of samoborska gora mts., trgovska gora mts. and ljubija are remarkably comparable in geology, mineralogy, geochemistry of fl uids and nature of metal sources. siderite deposits can be easily correlated with similar siderite deposits hosted within non– metamorphosed units of the inner dinarides (ljubija, nw bosnia), and with those in the zagorje–mid–transdanubian zone. these include; rudabanya (northernmost hungary, low er triassic), siderite–magnesite-polysulphide deposits in gemerides (rudnyani, nižna slana, jelšava and others), and siderite deposits in eastern alps (palinkaš et al., 2008; prochaska & henjes-kunst, 2007; hurai et al., 2002; radvanec et al., 2004). the rude deposits with characteristic geotectonic setting, structural geology, chemistry of ore forming fl uids, stable and radiogenic isotope composition of mineral parageneses, represents locus typicus of the permian siderite -barite-poly sulphide deposits in the western tethyan realm. acknowledgement this paper is a result of a large scale study and research activity under the projects, 119-0982709-1175, 098-0982934-2742 of the ministry of science, education and sports, republic of croatia, and the scopes project no. 7krpj065483.01, to whom we express our sincere gratitude. thanks also go to tihomir marjanac for constructive discussion and relevant literature on the problems of shock quartz and impact phenomena, and to vesna mar chig for geochemical and isotopic data on a gypsum sample, processed in the bundesanstalt, hannover. acknowledgement are also addressed to the reviewer vesnica garašić and ferenc molnár whose comments, suggestions and meticulous reduction greatly cleared up those statements which were taken clear as granted. references basch, o. (1981): osnovna geološka karta sfrj 1:100000, list ivanić grad, l 33–81 [basic geological map of sfr yugoslavia scale 1 : 100000, sheet ivanić-grad, l 33–81 – in croatian].– inst. geol. istraž., zagreb, sav. geol. zavod, beograd. bakker, r.j. (2003): package fluids 1. computer programs for analysis of fl uid inclusion data and for modeling bulk fl uid properties.– chem. geol., 194, 3–23. borojević šoštarić, s. (2004): geneza sideritno-baritno-polisulfi dnih ležišta u paleozoiku unutarnjih dinarida [genesis of the siderite–barite–polysulphide deposits within the palaeozoic blocks of inner dinarides – in croatian].– unpubl. m.sc. thesis, university of zagreb, 120 p. borojević šoštarić, s., palinkaš l.a., strmić palinkaš, s., bermanec, v., neubauer, f., spangenberg, j. & prochaska, w. (2009): origin of siderite mineralisations in petrova and trgovska gora mts., nw dinarides.– mineral. petrol., 97, 111–128. bottrell, s.h., yardley, b.w.d. & bucley, f. (1988): a modifi ed crush–leach method for the analysis of fluid inclusion electrolytes.– bull. mineral., 111, 279–290. channer, d.m.der., bray, c.j. & spooner, e.t.c. (1999): integrated cation–anion volatile fl uid inclusion analysis by gas and ion chromatography; methodology and examples.– chem. geol., 154, 59–82. claypool, g.e., holser, w.t., kaplan, i.r., sakai, h. & zak, i. (1980): the age curves of sulphur and oxygen isotopes in marine sulphate and their mutual interpretation.– chem. geol., 28, 199–260. crawford, m. (1981): phase equilibria in aqueous fl uid inclusions.– in: hollister, l. & crawford, m. (eds.): fluid inclusions: applications to petrology. mineral. assoc. canada short course, 6, 304 p. cumming, g.l. & richards, j.r. (1975): ore lead isotope ratios in a continuously changing earth.– earth planet. sci. lett., 28, 155–171. davis, d.w., lowenstein, t.k. & spencer, r.j. (1990): melting behaviour of fl uid inclusions in laboratory–grown halite crystals in the systems nacl–h2o, nacl–kcl–h2o, nacl–mgcl2–h2o, and nacl–cacl2–h2o.– geochim. cosmochim. acta, 54, 591–601. doe, b.r. & stacey, j.s. (1974): the application of lead istotopes to the problems of ore genesis and ore prospect evolution: a review.– econ. geol., 63, 757–776. doe, b.r. & zartman, e. (1979): plumbotectonics, the phanerozoic.– in: barnes, h. l. (ed.): geochemistry of hydrothermal ore deposits.– john wiley and sons, newyork, ny, 22–70. french, m.b. (1998): traces of catastrophe. lpi contribution no. 954.– lunar and planetary institute, houston, texas, 120 p. geologia croatica 63/1geologia croatica 114 grieve, r.a.f., langenhorst, f. & stöffler, d. (1996): shock metamorphism of quartz in nature and experiment: ii signifi cance in geoscience.– meteoritcs planet. sci., 31, 6–35. hardie, l.a. (1990): the roles of rifting and hydrothermal cacl2 brines in the origin of potash evaporates: an hypothesis.– amer. jour. science, 290, 43–106. herak, m. (1956): geologija samoborskog gorja.– acta geol., jazu, zagreb, i, 49–74. haas, j., mioč, p., pamić, j., tomljenović, b., arkai, p., berczi-makk, a., koroknai, b., kovacs, s. & felganhauer, e. (2000): complex structural pattern of the alpine–dinaric –pannonian triple junction.– int. j. earth. sci. (geol. rundsch.), 89, 377–389. horita, j., friedman, t.j., lazar, b. & holland, h.d. (1991): the composition of permian seawater.– geochim. cosmochim. acta, 55, 417–432. hurai, v., harcova, e., huraiova, m., ozdn, d., prochaska, w. & wiegerova, v. (2002): origin of siderite veins in the western carpathians – i. p-t-x-δ13c-δ18o relations in ore-forming brines of the rudnany deposits.– ore geol. rev., 21, 67–101. jurković, i. (1958): metalogeny of petrova gora mts. in southwestern croatia (in croatian).– geol. vjesnik, zagreb, 11, 143–228. jurković, i. (1959): polymetal paragenesis of the ore occurrence in the catchment area of the srebrenjak brook south of the town dvor na uni in croatia (in croatian).– geol. vjesnik, zagreb, 13, 149–161. jurković, i. (1960): mineralogical investigation of iron–ore deposit ljubija near prijedor in bosnia (in croatian).– geol. vjesnik, zagreb, 14, 161–220. jurković, i. (1961): minerali željeznih rudnih ležišta ljubije kod pri jedora [mineralogical investigation of iron–ore deposit ljubija near prijedor in bosnia – in croatian].– geol. vjesnik, zagreb, 14, 161–220. jurković, i. (1962): the results of ore deposit research in republic of croatia (in croatian).– geol. vjesnik, zagreb, 15/1, 249–294. jurković, i. (1988): hercinska metalogenija rudnih ležišta trgovske gore u hrvatskoj [the hercynian metallogenesis of the ore deposits of trgovska gora in croatia – in croatian].– geol. vjesnik, zagreb, 41, 369–393. jurković, i. & durn, g. (1988): lead deposit in the zrin district of trgovska gora in croatia.– geol. vjesnik, zagreb, 41, 317–339. kieffer, s.w. (1971): shock metamorphism of the coconino sandstone at meteor crater, arizona.– j. geophys. res., 76, 5449–5473. kieffer, s.w., phakey, p.p. & christie, j.m. (1976): shock processes in porous quartzite: transmission electron microscope observations and theory.– contr. mineral. petrol., 59, 41–93. köppel, v. (1983): summary of lead isotope data from ore deposits of the eastern and southern alps: some metallogenetic and geotectonic implications.– in: schneider, h.j. (ed.): mineral deposits of the alps and of the alpine epoch in europe. springer–verlag, berlin–heidelberg, 402 p. leach, d., marsh, e., bradly, d., gardoll, s. & huston, d. (2005): the distribution of sedex pb-zn deposits through earth history.– in: jingwen m. & bierlein f.p. (eds.): mineral deposit research: meeting the global challenge proceedings of the eighth biennial sga meeting beijing, 145–148. martin, j.m. & whitfield, m. (1983): the signifi cance of the river input of chemical elements to the ocean.– in: wong, c.s. & boyl, e. et al. (eds.): trace metals in sea water. plenum, new york, 265–296. mccaffery, m.a., lazar, b. & holland, h.d. (1987): the evaporation path of seawater and the coprecipitation of br– and k+ with halite.– j. sedim. petrol., 57, 928–937. murowich, j.b. & barns, h.l. (1986): marcasite precipitation from hydrothermal solution.– geochim. cosmochim. acta, 50, 2615–2630. naden, j. (1996): calcic brine: a microsoft excel 5.0 add–in for calculating salinities from microthermometric data in the system nacl–cacl2–h2o.– in: brown, p.e. & hagemann, s.g. (eds.): pacrofi vi, pan american conference on research on fluid inclusion. madison proceedings, 97–98. ohmoto, h. (1986): stable isotope geochemistry of ore deposits.– in: valley, j.w., taylor, h.p. jr. & o` neil, j.r. (eds.): stable isotopes in high temperature geological processes. rev. mineral., bookcrafters inc., chelsea, 16, 419–556. ohmoto, h. & rye, r.o. (1979): isotopes of sulphur and carbon.– in: barnes, h.l. (ed.): geochemistry of hydrothermal ore deposits. a wiley–interscience publication, new york, 509–561. ohmoto, h. & lasaga, a.c. (1982): kinetics of reactions between aqueous sulphates and sulphides in hydrothermal systems.– geochim. cosmochim. acta, 46, 1727–1745. palinkaš, a.l. (1985): lead isotopes patterns in galenas from some selected ore deposits in croatia and nw bosnia.– geol. vjesnik, zagreb, 38, 175–189. palinkaš, a.l. (1988): geokemijske karakteristike paleozojskih metalogenetskih terena: samoborske gore, gorskog kotara, like, korduna i banije [geochemical characteristics of palaeozoic metallogenic regions: samoborska gora mts., gorski kotar, lika, kordun and banija – in croatian].– unpubl. phd thesis, university of zagreb, 108 p. palinkaš, a.l. (1990): siderite–barite–polysulphide deposits and early continental rifting in dinarides.– geol. vjesnik, zagreb, 43, 181–185. palinkaš, a.l., borojević, s., strmić, s., prochaska, w. & spangenberg, j. (2003): siderite–haematite–barite–polysulphide mineral deposits, related to the early intra–continental tethyan rifting, inner dinarides.– in: eliopoulos, d.g. et al. (eds.): mineral explorations and sunstainable development. proceedings of the 7th biennial sga meeting athens, greece, 24–28 august, 2003, millpres, rotterdam, 1225–1228. palinkaš, l., borojević šoštarić, s. & strmić palinkaš, s. (2008): metallogeny of the north–western and central dinarides and southern tisia.– ore geol. rev., 34, 501–520. strmić palinkaš, s., spangenberg, j. & palinkaš, a.l., (2009): organic and anorganic geochemistry of ljubija siderite deposits, nw bosnia and herzegovina.– miner. deposita, 44, 893–913. pamić, j. & tomljenović, b. (1998): basic geological data from the croatian part of the zagorje–mid–transdanubian zone.– acta geol. hungarica, 41/4, 389–400. playa, e., cendon, d.i., trave, a., chivas, a.r. & garcia, y.a. (2007): using multiple geochemical proxies to trace origin of gypsum (gulf of carpentaria, australia, –70ka).– geogaceta, 42, 135–138. prochaska, w. & henjes-kunst, f. (2007): the origin of sparry magnesite in the eastern alps: evidence from inclusion fl uid and sr–nd isotope chemistry.– in: andrew, c.j. et al. (eds.) proceedings of the 9th biennial meeting of the society for geology applied to mineral deposits. dublin, iaeg, vol. ii, 823–826. radvanec, m., grecula, p. & žák, k. (2004): siderite mineralisation of the gemericum superunit (western carpathians, slovakia): review and a revised genetic model.– ore geol. rev., 24, 267–298. rising, b.a. (1973): phase relations among pyrite, marcasite and pyrrhotite below 300°c.– ph.d. dissertation, the pennsylvania state university, 192 p. palinkaš et al.: permian–polysulphide-siderite–barite–haematite deposit rude in samoborska gora mts... geologia croatica 115 roedder, e. (1984): fluid inclusions.– mineral. soc. amer. rev. mineral., 12, washington, 644 p. schoonen, m.a.a. & barnes, h.i. (1991): mechanism of pyrite and marcasite formation from solution: iii. hydrothermal processes.– geochim. cosmochim. acta, 55, 3491–3504. sheperd, t.j., rankin, a.h. & alderton, d.h.m. (1985): a practical guide to fl uid inclusion studies.– blackie and son ltd., glasgow, 239 p. stacey, j. & krammers, j.d. (1975): approximation of terrestrial lead isotope evolution by a two–stage model.– earth planet. sci. lett., 26, 207–221. šiftar, d. (1989): starost evaporita i podrijetlo sulfata u rudama [the age of evaporates and the origin of sulphate in rude deposit – in croatian].– geol. vjesnik, zagreb, 42, 59–64. šikić, k., basch, o. & šimunić, a. (1978): osnovna geološka karta sfrj 1:100 000. list zagreb. l33–80 [basic geological map of sfry 1:100000, zagreb sheet – in croatian].– inst. geol. istraž., zagreb (1972), sav. geol. zavod, beograd. šikić, k., basch, o. & šimunić, a. (1979): tumač osnovne geološ ke karte 1:100000, list zagreb [basic geological map of sfry 1:100 000, geology of the zagreb sheet – in croatian].– sav. geol. zavod, beograd, 81 p. šikić, k. (1995): geološki vodič medvednice [geological guide of medvednica – in croatian].– zagreb: inst. geol. istraž., zagreb, 199 p. šinkovec, b. (1971): geologija ležišta željezne i bakrene rude u ruda ma kraj samobora [geology of iron and copper ore from rude near samobor – in croatian].– geol. vjesnik, zagreb, 24, 165–181. taylor, s.r. & mclennan, s.m. (1985): the continental crust: its composition and evolution.– blackwell sci. publ., oxford, 309 p. tomljenović, b. (2000): zagorje–mid–transdanubian zone.– in: pamić, j. & tomljenović, b. (eds.): vijesti.– fieldtrip guidebook. proc. of the pancardi 2000, dubrovnik, croatia, 1–3 october, 2000, zagreb, 37/2, 27–33. tomljenović, b. (2002): strukturne karakteristike medvednice i samoborskog gorja [structural characteristics of the mts. medvednica and the samoborsko gorje mts. – in croatian].– unpubl. phd thesis, university of zagreb, 208 p. zartman, r.e. & heines, s.m. (1988): the plumbotectonic model for pb isotopic systematics along major terrestrial reservoirs – a case for bi–directional transport.– geochim. cosmochim. acta, 52, 1327–1339. zhang, y.g. & frantz, j.d. (1987): determination of the homogenisation temperatures and densities of supercritical fl uids in the system nacl–kcl–cacl2–h2o using synthetic fl uid inclusions.– chem. geol., 64, 335–350. manuscript received april 15, 2009 revised manuscript accepted february 10, 2010 available online february 28, 2010 korbar.indd 75 � ab stra ct velika palagruža (pelagosa) is the largest island of the palagruža archipelago (central adriatic sea, croatia). despite its minute size the island bears a certain geological interest being the only exposed piece of land in the central part (mid-adriatic ridge) of the common adriatic foreland of the apenninic and the dinaridic orogenic domains. the litho-, bio-, and chemostratigraphic (strontium and sulphur isotopes) characteristics of the sedimentary units, along with tectono-structural and geomorphic characteristics of the island, are described in this paper. the oldest žalo unit is composed of highly deformed siliciclastics containing gypsum, and carbonates of middle triassic (ladinian) age. this unit represents a transitional fl uvial-to-shallow marine, occasionally evaporitic environment, typical of the middle triassic rifting phase of the adriatic microplate. soft and strongly deformed žalo unit deposits are found along a probably still active, wnw–ese striking, subvertical, oblique-slip fault that crosses the entire length of the island. the žalo unit is probably in diapiric contact with the lanterna unit, poorly defi ned as late triassic, and characterized by dolomite with chert and dolomite breccia, presumably deposited in a transitional platform-to-basin environment of an evolving adriatic basin. the lanterna unit deposits are capped by miocene biocalcarenites of the salamandrija unit over an almost perpendicular discordance, possibly representing an unconformity, suggesting that an early deformational phase preceded a miocene marine transgression. talus, landslide deposits, and humic soil make up the cover of the bedrock sedimentary succession, and they represent the ultimate phase of emersion of the island, which probably occurred during pliocene(?) to quaternary times. an active neotectonic regime of the central adriatic is evidenced by present-day seismicity, while recent uplifting of the island is shown by the presence of remnants of pebbly palaeobeach deposits, marine (erosional) straths, and cyanobacterial supratidal encrustations (pelagosite) currently observed at various elevations above mean sea level. keywords: carbonate platform, basin, triassic, neogene, mid-adriatic ridge, recent uplift geologic reconnaissance of the island of velika palagruža (central adriatic, croatia) � tvrtko korbar1, alessandro montanari2, georg koch1, sandro mariani2, don depaolo3, alexandra v. turchyn4, mirjana miknić1 and vlasta tari5 1 croatian geological survey, department of geology, sachsova 2, hr-10000 zagreb, croatia; (tvrtko.korbar@hgi-cgs.hr) 2 osservatorio geologico di coldigioco, 62021 apiro, italy 3 department of earth and planetary science, university of california, berkeley, ca 94720-4767-u.s.a. 4 department of earth sciences, cambridge university, downing st., cambridge, cb2 3eq, united kingdom 5 exploration department, ina-naftaplin, šubićeva 29, hr-10000 zagreb, croatia doi: 10.4154/gc.2009.07 geologia croatica 62/2 75–94 15 figs. 2 tabs. zagreb 2009 geologia croaticageologia croatica geologia croatica 62/2geologia croatica 76 1. introduction and previous work velika palagruža (pelagosa in italian) is a small island in the central adriatic sea, the largest within the palagruža archipelago (fig. 1). the island is placed within the common adriatic foreland of the apennines and the dinarides, 57 km from the gargano promontory to the south, and 60 km from the island of lastovo to the northeast. the distance from the mainland as well as steep slopes and a hostile rocky coast, makes access to the island rather diffi cult. a handful of published studies be counted since the fi rst geological and palaeontological reconnaissance of the island of palagruža was carried out by stur (1874), at about the time when the austrians were building the monumental lighthouse on the highest point of the island. palagruža was then revisited by stache (1876) and, independently, by marchesetti (1876). further geological studies were carried out by bo žičević et al. (1965). the authors proposed a middle jurassic age for the basal dolomite formation based on the presence of lithothamnion, and a miocene age for the biocalcarenitic limestone at the top of the succession, according to the foraminiferal and mollusc association. the stratigraphic bedrock succession of velika palagruža is capped by pliocene(?) to quaternary talus breccias and humic soil. the authors of the explanatory notes for the basic geological map sheet (korolija et al., 1977) proposed a jurassic age for a siliciclastic unit with gypsum exposed near the beach of žalo (see fig. 2 for location), based on a general lithological analogy with the komiža complex on the island of vis (at the time considered to be of jurassic age), and stratigraphic relationships with the underlying dolomites containing chert nodules of proposed late jurassic age. korolija et al. (1977) argued for the late cretaceous age of the overlying biocalcarenites exposed in a quarry pit at salamandija (see fig. 2 for location). sokač et al. (1980) identifi ed the foraminifera meandrospira pusilla from a small outcrop of siliciclastic-evaporitic rocks near žalo containing sandstones, gypsum, clay, and silt, which, along with results from mineralogical analyses, indicated an early triassic or possibly even older (late permian) age. the authors, in agreement with the interpretation of korolija et al. (1977), viewed this siliciclasticevaporitic unit at žalo as a diapir. the diapiric setting of the palagruža block was suggested by grandić et al. (2002) following seismo-stratigraphic interpretation. grandić et al. (2002) also referred the broader area of the palagruža archipelago to the jurassic to palaeogene adriatic basin domain. gypsum often occurs in upper permian to triassic formations throughout the alpine domain, and represents shallow water evaporitic environments during an early subsidence phase of the adriatic microplate, which was probably attached to the african continental crust (e.g. channell et al., 1979; bosellini, 2002). however, the stratigraphic position of adriatic evaporites and associated rocks is often doubtful, mainly due to their chaotic setting. from the few geologic reports cited above it appears that palagruža has a geological complexity and overall importance much bigger that its own minute size, which defi nitively demands more detailed study. the results of a preliminary geological survey are reported here, which highlights the stratigraphic and structural complexity of this island. while some uncertainties still remain in the accurate chronostratigraphic assessment of the main rock formations, structural and geomorphic features exposed in the island offer new evidence for a past and recent history of geodynamic events. 2. regional geological and tectonic settings palaeogeographically, the central adriatic area is considered to represent a jurassic to palaeogene adriatic basin enclosed between the apulia carbonate platform to the southwest (italy), and the adriatic (dalmatian) carbonate platform to the northeast (croatia) (zappaterra, 1994; bosellini, 2002; grandić et al., 2002; tari, 2002; vlahović et al., 2005). at present, the succession of mostly pelagic forfi gu re 1: simplifi ed geotectonic map of the wider adriatic region, and location of the palagruža archipelago. korbar et al.: geologic reconnaissance of the island of velika palagruža (central adriatic, croatia) geologia croatica 77 mations of the central adriatic basin is covered by thick neogene siliciclastic deposits (bertotti et al., 2001). the se formations are known from boreholes and seismic profi les (e.g., grandić et al., 2002, and references therein), and palagruža is the only place in the whole region where some of these units are exposed above sea level. bognar (1995) proposed that palagruža represents a “pop-up” structure, which consists of a fault-bounded fragment of continental crust that is being pushed laterally and vertically by compressional tectonic forces. in other words, palagruža is uplifting due to the head-on collision between the converging apenninic and dinaridic orogenic systems (fig. 1), and, for this very reason, it is subject to seismic activity. through modelling gps measurements of crustal velocity along a transverse profi le across the southern adriatic microplate and south-central dinarides, bennett et al. (2008) assumed a nne dipping thrust fault, which surfaces along the offshore of southern dalmatia, between the islands of vis and palagruža, not far north of palagruža. bennett et al. (2008) argued for sw-migrating deformation in an active fold-and-thrust belt as a consequence of uninterrupted subduction of the southern adria mantle lithosphere beneath eurasia since the eocene. in this tectono-seismic scenario, palagruža is located on the footwall of the thrust not far from its line of emergence to the north, and its present horizontal movement toward the ne in respect to fi xed eurasia is about 5 mm/yr (bennett et al., 2008). recent regional seismic-stratigraphic data (grandić et al., 2002) suggest that diapirism probably contributes to the current crustal uplifting along two wnw–ese divergent reverse faults (suggesting transpression), which delimit the palagruža submarine rise – palagruža high (bertotti et al., 2001) or mid-adriatic ridge (grandić et al., 1997; geletti et al., 2008), in the southern and northern off shore of the island. geletti et al. (2008) argued for a miocene onset of the diapirism, according to seismostratigraphic interpretations, whereas the related deformations continue to date. at present, the central adriatic is seismically active (e.g. herak et al., 1996; grandić et al., 2002; chiarab ba et al., 2005; ridente & trincardi, 2006). the most important seismic event in recent times was represented by the 1988 swarm, which started in february 1988, and ended early in 1989. more than 100 quakes > 3m were recorded during this period, with epicenters spread over an area about 30 km long (in a ne–sw direction) and 20 km wide (herak et al., 1996). the largest earthquake of this sequence reached a magnitude of 5.3, and its epicenter was located 38 km se of palagruža, with a focal mechanism indicating slightly oblique reverse faulting with an e–w strike (ridente & trincardi, 2006). this is consistent with the general deformation on strike-slip and thrust faults resulting in ne–sw shortening along the eastern coast of the adriatic sea (battaglia et al., 2004). in summary, the mid-adriatic ridge belongs to the adriatic foreland, and its origin is related to combined strike-slip faulting and vertical salt movement. palagruža is probably placed at the topmost part of an active diapiric structure characterized by a very deep root. 3. sedimentary units and tectonics the sedimentary units exposed at velika palagruža are described according to direct observations of key outcrops and their distribution in our original geologic map (fig. 2), which highlights the remarkably complex geology of this tiny island. however, it should be stressed that a more precise age determination, as well as more detailed stratigraphic and tectonic relationships between the sedimentary units, requires further research. nevertheless, the units are described below and are organized according to their proposed stratigraphic position. 3.1. žalo unit an outcrop of stratifi ed yellowish siltstones and green-grey claystone associated with gypsum is located in the southern central part of the island, about 50 m west of a fi shermans shack at the western end of žalo beach (location 1, fig. 2). these rocks comprise a stratigraphic succession from a basal homogeneous green-gray clay unit, to a lens of fractured white gypsum about 1.5 m thick, overlain by a fi nely stratifi ed clay-rich siltstone unit containing disperse gypsum, and terminating with a second horizon of green-gray clay-rich siltstone (fig. 3a). fragments and whole shells of microgastropods, and small vertebrate bones were observed in a sample of green-gray clay/claystone from the žalo outcrop, but have not so far yielded a taxonomic determination. the succession is covered by a rockfall of dolomite boulders. apart from the fractured gypsum, where greengray clay fi lls the fractures (fig. 3b), this outcrop appears undeformed, with regular, parallel bedding constantly dipping 32°ne. the green-gray clay of the žalo unit is also exposed in the lower part of a ravine at picokare, about 200 m further west (fig. 4a). some metres above this outcrop, a package of thin-bedded, beige-yellowish dolomite layers are exposed, with a dip of 27°nw. unfortunately, the contact between the clay and this thin-layered unit is not exposed, but it seems that the žalo unit occupies this part of the island, from the fi sherman shack at žalo beach to the picokare gully, and it is covered by boulder rock fall and south-dipping coarse talus (see figs. 2 and 4a). on the other hand, the contact between the žalo unit clay and the lanterna unit dolomite with chert (see section 3.2.) to the west of the picokare ravine, is well exposed, and it is represented by a sharp discordance (fig. 4a). practically, the thick-bedded dolomite layers with chert of the lanterna unit (unit a, see below), which dip steelpy to the sw, are cut by a fl at and smooth undulatory surface, with a dip of about 45° toward the e. the clay of the žalo unit is found resting on top, against this surface (fig. 4b). we are still uncertain on the exact nature of this discordance, which does not appear to be a simple angular unconformity. we do not exclude that the fl at discordance surface is actugeologia croatica 62/2geologia croatica 78 ally a deformed fault pla ne, as some oblique slickenside striations on the smooth surface suggest, and that the žalo unit has been put in place against the already tilted lanterna dolomites by the combined action of oblique-slip faulting and diapiric uplifting. however, the age relationship between the žalo unit and the lanterna unit is still uncertain (see below), which limits the plausibility of the interpretation for this rather odd structural situation. another key exposure of the žalo unit is located on the southeasternmost coast of the island, south of a locality called jonkova njiva (fig. 5a). as at picokare, the žalo unit rests on top of thick-bedded dolomite layers of the lower part of the lanterna unit (i.e., unit a in the legend of fig. 2). the rocks, which include marly siltstones containing disperse nodules of gypsum, and a few layers of stromatolitic limestone, are strongly deformed (fig. 5b). on the north side of fi gu re 3: a) outcrop of the siliciclastics and gypsum of the žalo unit west of the žalo beach; b) close up of the fractured gypsum with greenish-gray clay fi lling in the cracks. fi gu re 2: geologic map and synthetic stratigraphic column of the island of velika palagruža. sampling locations on inserted map (not in scale): 1 – samples pal–5 and pal–6; 2 – samples pal–22 and pal–23; 3 – sample pal–14; 4 – sample pal–16; 5 – sample pal–12d; 6 – samples pal–10 and pal–13. a b korbar et al.: geologic reconnaissance of the island of velika palagruža (central adriatic, croatia) geologia croatica 79 this outcrop a wnw–ese striking subvertical oblique-slip fault puts the žalo unit in contact with strongly deformed, medium-thick bedded dolomites and dolomite breccias of the presumed upper part of the lanterna unit (unit b). this fault is probably the continuation of the oblique-slip fault that dissects the whole length of the island from stara vlaka on the nw, to the southeastern point of jonkova njiva, where žalo unit rocks occur in a strongly deformed fault zone. a similar situation is found on the south side of the stara vlaka cove (figs. 2 and 6), where strongly deformed thinbedded dolomites and green-grey clay are found within the highly tectonized zone of the same oblique-slip fault (fig. 6a and b). 3.1.1. palynostratigraphy of the žalo unit to overcome the age uncertainty of the žalo unit, and assess its palaeoenvironmental and biostratigraphic attributes, a detailed palynological study of a number of soft rock samples from various outcrops throughout the island, was undertaken. sample pal–5 (žalo unit gypsum, w of žalo beach, location 1 on fig. 2) is palynologically barren. sample pal–6 (žalo unit silty claystone, w of žalo beach, location 1 on fig. 2). palynofl ora of the sample pal–6 (appendix 1 and fig. 7) is represented by a diverse and wellpreserved assemblage of predominantly sporomorphs and may well be correlated to the palynofl ora of the european and circum-mediterranean independently dated ladinian sections (visscher & brugman, 1981; warrington, 2002; schulz & heunisch, 2005). in the alpine region of the dolomites in italy, the palynofl ora of sample pal–6 corresponds to the palynological secatus – dimorphus phase of van der eem (1983). this type of palynofl ora has been described from sections of southeastern switzerland (scheuring, 1978) and the dolomites (blendinger, 1988; hochuli & roghi, 2002), as well as from liechtenstein,western austria (brühwiler et al., 2007) and hungary where it has been designated as meieri – scheuringii phase (góczán & oravecz-scheffer, 1993; kovács et al., 1994). the secatus – dimorphus pha se concours with the ammonoid gredleri zone and archelaus zone (van der eem, 1983; brugman, 1986), which, according to brack et al. (2005), are late fassanian–early langobardian in age. among the stratigraphically signifi cant sporomorphs that are shared between the secatus – dimorphus phase and the palynofl ora of sample pal–6, heliosaccus dimorphus has a range within the secatus – dimorphus phase whilst camerosporites secatus, duplicisporites granfi gu re 4: a) panoramic view of the picokare ravine from the south, showing discordance (?diapiric contact) between the žalo unit clay and the subvertical, thick-bedded dolomites with chert of the lanterna unit a, both capped by stratifi ed talus; b) close up (from above) of the contact between extremely deformed greenish clay of the žalo unit and the dolomite of the lanterna unit a. fi gu re 5: a) panoramic view of the outcrop of the žalo unit near jonkova njiva, and b) close up of the discordant (?diapiric) contact with the underlying lanterna unit a. a b a b geologia croatica 62/2geologia croatica 80 ulatus, sellaspora rugoverrucata, kyrtomisporis ervei and brachysaccus neomundanus fi rst appear at the base of the early fassanian ammonoid curionii zone (earliest ladinian), i.e. plurianulatus – secatus phase (van der eem, 1983; brugman, 1986). according to brühwiler et al. (2007), the fi rst appearance of c. secatus and d. granulatus is higher and corresponds to the base of secatus – dimorphus phase of the ammonoid gredleri zone. last appearance of cannanaropollis scheuringii is at the top of late langobardian (latest ladinian) secatus – vigens phase which correspond to the ammonoid regoledanus zone (van der eem, 1983; brugman, 1986). the last appearance of this taxon has been found at the top of the ladinian also in other parts of the alpine facies (scheuring, 1978; góczán & oravecz-scheffer, 1993; kovács et al., 1994). several taxa of the pal–6 palynofl ora also occur in other alpine sections, e.g. haberkornia parva/gudati and podosporites amicus, ranging approximately with the secatus – dimorphus phase, and doubingerispora fi lamentosa, which fi rst appears at the base of the ladinian. sample pal–6 also contains the stratigraphically signifi cant sporomorphs staurosaccites quadrifi dus, ovalipollis pseudoalatus and partitisporites spp., which fi rst appear at the base of the plurianulatus – novimundanus phase of the ammonoid nevadites sp. (=secedensis) zone, previously considered as early fassanian (earliest ladinian) by van der eem (1983) and brugman (1986). after the acceptance of the gssp for the base of the ladinian stage at the base of the ammonoid curionii zone (brack et al., 2005), the plurianulatus – novimundanus phase represents the latest anisian palynofl oral development. the plurianulatus – novimundanus phase contains, in the lower part, the late anisian sporomorphs stellapollenites thiergartii and dyupetalum vicentinense, and its top is defi ned by the last appearance of illinites chitonoides and concentricisporites plurianulatus (brugman, 1986). since these sporomorphs have not been identifi ed in the sample pal–6, the pre sence of s. quadrifi dus, o. pseudoalatus and partitisporites spp. alone suggests an age not older then earliest ladinian. considering the highest range of the sample pal–6 palynofl ora, the lack of enzonalasporites vigens, weylandites magmus, and “lueck is porites” cf. singhii, which fi rst appear at the base of secatus – vigens phase of the ammonoid regoledanus zone, treat ed as late langobardian (latest ladinian) (van der eem, 1983, brugman, 1986; broglio loriga et al., 1999), suggests an age not young er than latest ladinian. in the germanic facies, the palynofl ora of sample pal–6 corresponds to the palynological record of the lettenkohle successions (lower keuper). in poland, orłowska-zwolińska (1983) designated the lettenkohle palynofl ora as representing the heliosaccus dimorphus zone. in germany, several palynological zones, phases and subphases have been described, which allowed correlation to the alpine time equivalents (reitz, 1985; heunisch, 1986; van den bergh, 1987; brugman et al., 1988; van bergen & kerp, 1990; brugman et al., 1994; beutler et al., 1996; heunisch, 1999). the palynofl ora of the lettenkohle successions in france correspond to the correlatives in other parts of the germanic facies (adloff et al., 1984; courtinat & rio, 2004). the palynofl ora of the lettenkeuper has been dated bas ed on both independent control and palynological correlation with the alpine record. the palynofl oral record from southern germany, which is enhanced within the iliacoides – dimorphus sub/phase (van den bergh, 1987; brugman et al., 1988) and perforatus – dimorphus phase of (van bergen & kerp, 1990; brugman et al. (1994), corresponds to the alpine secatus – dimorphus phase. in the circum-mediterranean region of spain, the palynofl ora of sample pal–6 corresponds to the secatus – meieri subphase of besems (1983) which represents the lower part of the camerosporites secatus phase (visscher & krystyn 1978; visscher & van der zwan, 1981; van der eem, 1983) and is similar to the palynofl ora of lettenkohle as described by garcia gil & diez (2006). in libya, adloff et al. (1986) reported on a palynofl ora, which they correlate, to the alpine secatus – dimorphus phase of van der eem (1983). in israel, eshet (1990) described the palynofl ora from the ammonoid controlled section which has been assigned to the podosporites amicus zone corresponding in many elements to the european correlatives. syrian subsurface sections revealed a palynofl ora which yaroshenko & bash imam (1995) and lučić et al. (2003) compare to the palynofl oras of the circum-mediterranean and european ladinian correlatives. fi gu re 6: a) panoramic view of the western point of velika palagruža looking east with the indications of the geologic features described in the text; b) the exposure at stara vlaka cove showing the fault contact between a tectonized žalo unit and the dolomite breccia of the lanterna unit b, and the discordant contact with the thick-bedded dolomite of the lanterna unit a. the dolomite breccia of lanterna unit b is covered by a pebbly palaeobeach deposit resting below a talus slope. a b korbar et al.: geologic reconnaissance of the island of velika palagruža (central adriatic, croatia) geologia croatica 81 fi gu re 7: palynomorphs and palynofacies of the žalo unit claystone sample pal–6 (location 1 on fig. 2). autochthonous ladinian: 1) kyrtomisporis ervei, 2) doubingerispora fi lamentosa, 3) cannanoropollis scheuringii, 4) heliosaccus dimorphus, 5) lunatisporites acutus, 6) striatoabieites balmei, 7) triadispora plicata, 8) ovalipollis pseudoalatus, 9) staurosaccites quadrifi dus, 10) haberkornia parva, 11) duplicisporites verrucosus, 12) camerosporites secatus, 13) aulisporites astigmosus, and 14) veryhachium sp., 15) palynofacies. reworked lower triassic: 16) densoisporites nejburgii and 17) endosporites papillatus. geologia croatica 62/2geologia croatica 82 along with the authochtonous ladinian palynofl ora, sample pal–6 also contains reworked sporomorphs (appendix 2, fig. 7/16, 17), among which, endosporites papillatus and densoisporites nejburgii suggest reworking from lower triassic successions. several sporomorphs assigned as cf. lueckisporites virrkiae, limitisporites sp. and cf. nuskoisporites sp. indicate reworking most likely from permian successions. from the palynological point of view, the palynofl ora of sample pal–6 is almost identical to the palynofl ora from the surface sections of the diapiric structure at komiža, the island of vis (belak et al., 2005), which has been designated as the dimorphus interval zone and interpreted as late fassanian–early langobardian in age. at the komiža site, belak et al. (2005) also reported discovery of the dasycladal alga diplopora nodosa with a late anisian–ladinian range according to grgasović & sokač (2003) as well as the problematic taxon plexoramea cerebriformis with a middle anisian–carnian range according to goričan et al. (2005). at present, the fi ndings of d. nodosa represent the stratigraphycally narrowest independent control of the described palynofl ora in the area under consideration. sample pal–14 (žalo unit clay, stara vlaka cove, location 3 on fig. 2) contains a moderately to poorly preserved palynofl ora, predominantly of sporomorphs, generally similar to the palynofl ora of sample pal–6, and may therefore be considered ladinian in age. sample pal–22 (žalo unit stromatolitic limestone, se of jonkova njiva, location 2 on fig. 2) contains a small amount of degraded palynological organic matter and only a few poorly preserved bisaccate pollen grains and cf. camerosporites secatus suggesting a ladinian–carnian age. sample pal–23 (žalo unit marly siltstones, se of jonkova njiva, location 2 on fig. 2) contains palynofl ora similar to pal–14. however, the assemblage is less diverse allowing an age assignment within a wider ladinian–carnian range. 3.1.2. age of the žalo unit according to the palynostratigraphy reported here (section 3.1.1., appendix 1, fig. 7/1–15), the žalo unit was dated as middle triassic in age (ladinian). the žalo unit was dated as lower triassic by sokač et al. (1980), according to the lower triassic foraminifera meandrospira pusilla found in limestone microlithoclasts of quartzose calcarenitic sandstones. unfortunately, neither the sandstones mentioned by sokač and co-workers, nor the microfossils were found within analysed outcrops or elsewhere in the žalo unit. however, redeposited lower triassic palynomorphs were found (see chapter 3.1.1., appendix 2, fig. 7/16, 17). thus, it is suggested that sokač et al. (1980) reported on presumably ladinian sandstones containing redeposited lower triassic limestone microlithoclasts. 3.1.3. palynofacies of the žalo unit the composition of the palynological organic matter of samples pal–6, pal–14 and pal–23 is almost identical. sample pal–6 (fig. 7/15) is characterized by a better preservation state of the organic matter in respect to other samples. most of the organic matter consists of fragments of woody tissue (90%) followed by leaf (cuticle) remains (5%), and palynomorphs (5%). opaque clasts of presumably woody tissue (as suggested by the shape of the clasts) are rare (<1%). amorphous organic matter and structureless organic matter occur in traces showing thier liptinitic origin under blue light. woody tissue is represented by brown to dark-brown, partly well structured, variably sized (mostly 5–50 μm, partly up to 400 μm) and shaped (equidimensional to lath-shaped) particles that are predominantly angular and weakly sorted. cuticle remains most ly occur as well preserved, structured fragments (50–500 μm). most of the palynomorphs are well pre served and represented predominantly by terrestrial palynomorphs, i.e. sporomorphs (94%) of which bisaccate pollen (64%) is most abundant, followed by circumpolles (20%), spores (10%), monosaccate pollen (3%), and asaccate pollen (3%). aquatic palynomorphs (6%) are mostly represented by prasinophyceans (60%) followed by acritarchs (34%), and chlorophyceans (6%). pyrite inclusions have not been observed. samples pal–14 and pal–23 differ from pal–6 in a somewhat lower abundance of cuticle fragments as well as their lower abundance and diversity of sporomorph assemblages. the palynological composition of the sedimentary organic matter of the analyzed samples indicate that this silty claystone was deposited in a low-energy, dysoxic environment, proximal to the input of terrestrial organic matter and under fl uvial and open marine infl uence, and may, therefore, be characterized as marine-brackish-fl uvial tidal fl at (cf. tyson, 1995 and batten, 2002). the environmental interpretation of sample pal–6 can be also applied to that for samples pal–14 and pal–23 since their palynofacies features are almost identical. sample pal–22 contains a small amount of palynological organic matter mostly consisting of amorphous organic matter (95%), part of which is represented by clasts of fragmented cyanobacterial laminae. woody tissue (5%) is weakly structured. sporomorphs occur in very low frequency. except for a few leiosphaeridia, other aquatic palynomorphs have not been observed. the palynofacies features of sample pal–22 suggest a carbonate, shallow water depositional setting with scarce terrestrial input. 3.1.4. palaeoclimatological and palaeoenvironmental intepretation of the žalo unit for the purposes of palaeoclimatological/palaeoenvironmental interpretation, the palynomorphs are grouped into categories indicating their botanical affi nity and ecological sensitivity (appendix 3) according to visscher & van der zwan (1981), brugman et al. (1994), visscher et al. (1994) and roghi (2004). groups a–g are of equisetophytic, lycopodiaphytic and pterophytic and category h of bennettitalean and gnetalean affi nity. groups a–h refl ect hygrophytic plant communities of swamps, marshes, mangrovas and generally wet and water-saturated substrates of fl uviatile and lacustrine environkorbar et al.: geologic reconnaissance of the island of velika palagruža (central adriatic, croatia) geologia croatica 83 ments. group i is of bryophytic and group j is of pteridosperm origin while groups k–p are of coniferalen affi nity, respectively. groups i–p refl ect xerophytic plant communities of hinterland vegetation. group p represents prasynophycean algae and group q coenobial chlorophycean algae which refl ect freshwater-brackish to intertidal shallow marine and lagoonal depositional sets. group q represents phytoplankton of marine environments. the quantitative distribution of the groups within the palynofl ora of pal–6 (appendixes 1 and 3) shows that the groups k–p constitute 80% of the whole palynological assemblage indicating predominantly xerophytic plant communities which suggests semi-arid climate conditions. this may well be supported by high frequencies of group l (ovalipollis/staurosaccites; 26.6%) and group p (circumpolles; 19.8%), which are indicators of regional aridity, and a high frequency of bisaccate pollen (64%) indicating the proximity of xerophytic plant communities of the hinterland vegetation. 3.1.5. sulphur isotopes of the žalo unit gypsum to separately test the triassic age for the žalo unit, we analyzed the sulfur isotope composition (δ34s) of selenitic gypsum from the outcrop pal–5, (location 1, fig. 2). sulfur isotope measurements were made both on original evaporite minerals and on samples that were leached in water and reprecipitated as barium sulfate prior to isotope analysis. both replicates are presented in table 1. the isotope analyses are in parts per thousand or ‰ and the standard is the canon diablo troilite (cdt). the analytical error of the isotope measurement is ±0.2‰. in theory, the δ34s of marine gypsum or other sulfateevaporite mineral should be related to the δ34s of global marine sulfate at the time the evaporite formed (šiftar, 1987). the δ34s of global ocean sulfate was distinct in the miocene (22‰) from the permian to triassic (~10 to 15‰). using the δ34s of an evaporite mineral as a geochronological indicator can however be problematic. first, there can be isotope dynamics associated with evaporating basins; sulfur isotopes can be fractionated during precipitation and progressive evaporation and this will impact on the δ34s of the sulfate in the evaporitic brine. second, and more problematically, the sulfate that is used to form the evaporite mineral could come not from ocean-sulfate but from oxidized hydrogen sulfi de (h2s). h2s forms from bacterial sulfate reduction in anoxic sediments and rocks; because of sulfur isotope fractionation during bacterial sulfate reduction, the h2s formed has a δ34s that is 10 to 50‰ lower than the original sulfate. if this h2s migrates and then oxidizes, the sulfate formed during oxidation will also be isotopically “light” and distinct from seawater sulfate. for example, the microcrystalline gypsum slush mass found in the frasassi caves (italy) has δ34s of –13.7‰, and was likely formed from subaerial reaction between h2s and a lower jurassic limestone of the calcare massiccio formation (e.g. mariani et al., 2007, and references therein). in this case, the h2s originates from reductive dissolution of a triassic anhydrite in the underlying triassic burano formation. the sample from palagruža (gyp) has a similar δ34s of –11.4‰, which suggests that the source of the sulfate for this gypsum is not seawater, but instead reoxidized h2s. if the palagruža gypsum were precipitated directly from miocene, triassic or permian seawater then we would expect values similar to those typical for marine evaporites. therefore, we cannot use the δ34s of the palagruža gypsum to place this unit in the chronological context. 3.2. lanterna unit the most widespread rocks found at palagruža are grey, hard, cryptocrystalline dolomites, all of which make up the lanterna unit. except for the area covered by humic soil, rock fall, and talus on the northern side of the island and at picokare, this unit is well exposed on the coastal cliffs all along the perimeter of the island (fig. 2), and it includes mediumto thick-bedded dolomite and irregular bodies of massive dolomite breccia. however, in many places the rocks are strongly deformed, fractured, and tectonically brecciated to the point that it is often diffi cult to discern primary bedding. moreover, dolomitization has also obliterated internal structures and fossils of the source limestone, which prevents palaeontological age and palaeoenvironmental determinations. nevertheless, we have distinguished two subunits in the whole dolomite body of the island (unit a and unit b; see legend in fig. 2) on the basis of bedding thickness and style, and the presence of nodular chert. however, the stratigraphic relationship between these two subunits is uncertain as they are separated by the oblique-slip fault, which cuts across the whole length of island from wnw to ese. the lanterna unit a makes up the southwestern, most elevated part of the island, and both the northeastern and southeastern points of the jonkova njiva promontory. this unit would correspond to “the basal dolomite” described by božičević et al. (1965). in the southern cliffs below the lighthouse between picokare and biljovka, beds dip steeply (subvertically) to the southwest (fig. 2). elsewhere in the northern sector of the island, bedding is not clear due to strong tectonization and the presence of massive bodies of coarse dolomite breccia. its most distinguishing feature is mediumto thick-bedded cryptocrystalline dolomite containing nodules and lenses of gray chert aligned along bedding (fig. 8). thin-bedded dolomites interbedded with softer silty dolomite occure in the lowermost part of the unit (fig. 9). gray to beige, medium to thin-bedded dolomite devoid of chert nodules is the distinguishing feature of the lanterna unit b, which makes up most of the central-northern part of the island (fig. 2). the unit b is often strongly tectonized, and contains massive bodies of coarse dolomite breccia (fig. 6b). table 1: δ34s isotope data from samples of palagruža žalo unit gypsum (location 1 on fig. 2; fig. 3) sample id d34s vcdt elemental composition gyp-a –11.4 16.1 gyp-c –11.5 12.7 gyp-d –11.1 12.0 geologia croatica 62/2geologia croatica 84 3.2.1. palynology of lanterna unit a we analyzed a soft interbed of yellowish silty dolomite of the lanterna unit a exposed at the fi rst switchback on the trail to the lighthouse (sample pal–12d; location 5 on fig. 2; fig. 9), and in the coastal outcrop sw of stara vlaka (sample pal–16; location 4 on fig. 2). sample pal–12d is palynologically barren whereas sample pal–16 revealed a poorly preserved, undiversifi ed sporomorph assemblage containing cf. patinasporites densus, which fi rst appears close to the base of the carnian, i.e. at the base of the ammonoid aon zone palynologically characterized as the vigens – densus phase by van der eem (1983), and at the base of the ammonoid canadensis zone designated as assemblage b by broglio loriga et al. (1999), respectively. occurrences of weakly preserved cf. camerosporites secatus may suggest that sample pal–16 is likely to be carnian in age since its last appearance is placed at the top of carnian (visscher & brugman, 1981; warrington, 2002). sample pal–16 contains a small amount of organic matter, insuffi cient for palynofacies analysis or palaeoclimatological/palaeoenvironmental interpretation. 3.2.2. age and paleoenvironment of the lanterna unit a the age of the lanterna unit a is poorly defi ned as late triassic, according to palynological results (see section 3.2.1.). radiolarians reported by korolija et al. (1977) from the chert nodules of lanterna unit a, and traces of lithothamnion reported by božičević et al. (1965), would indicate an age not older than middle jurassic for this formation. unfortunately, neither microfossils nor macrofossils could be determined in the numerous samples of dolomite inspect ed in the fi eld, or studied in thin sections. it is likely that dolomitization of the parent limestone, which led to a cryptocrystalline textural homogenization of these rocks, would have obliterated any original internal structure or microfossil trace. the study of thin sections from the lanterna unit chert nodules (picokare and stara vlaka, fig. 8) did not reveal any radiolaria or any other kind of microfossil, nor lithic grains, which could have aided age assessment and determination of a palaeoenvironment setting for these rocks. however, the poorly preserved palynofl ora of pal–16 including patinasporites, enzonalasporites, camerosporites and bisaccate pollen, suggests a semi-arid climate since these taxa represent coniferalean, xerophytic plant communities. it should be noted that chert is common in the late triassic transitional and basinal limestone and dolomite successions of the southwestern apennines (i.e. the lagonegro-molise basin; bertinelli et al., 2005; servizio geo logico d’italia, 2007). these carbonate rocks also include breccia, shale, marl and siltstone units, but dolomitization seems to be restricted to the upper triassic calcari con selce formation, which represents proximal to transitional depositional environments. dolomitization is not present in the calcari con selce in distal, deep-water successions. thus, based on palynostratigraphy (section 3.2.1.) and the analogy with the central and southern apenninic formations, we presume that the lower part of the lanterna unit may represent proximal or transitional carbonate platform-to-basin deposits of late triassic age. 3.3. salamandrija unit the central part of velika palagruža (salamandrija) is characterized by a regular, fl at area, which dips toward the nne, and is mostly covered by humic soil. a small quarry pit located some 50 m ne of the archaeological site of salamandrija (kirigin & čače, 1998; forenbaher & kaiser, 2005; fig. 2) reveals that this point of the island is composed of thick layers of light-grey to yellowish, porous bio-intra-lithoclastic to skeletal packstones and grainstones (biocalcarenites). another outcrop occurs on the trail to the lighthouse, along the wnw–ese striking fault (fig. 2), separating the unit from the underlying rocks. therefore, it is not possible to determine the exact stratigraphic relationship of this unit with the underlying rock units without new detailed fi eld investigations. nevertheless, the bedding attitude of the salamandija unit exposed in the quarry pit is approfi gu re 8: chert nodules and layers of gray chert aligned along bedding of the lanterna unit a dolomite (stara vlaka cove). fi gu re 9: outcrop of upper triassic thin-bedded dolomite interbedded with softer silty dolomite – lanterna unit a (location 5 on fig. 2). scale bar in cm. korbar et al.: geologic reconnaissance of the island of velika palagruža (central adriatic, croatia) geologia croatica 85 ximately perpendicular in respect to the lanterna unit b expos ed along the crest of the island, suggesting a sharp angul ar unconformity. 3.3.1. biostratigraphy and depositional environment of the salamandrija unit study of thin sections of the salamandrija biocalcarenite (samples pal–10 and pal–13, location 6 on fig. 2) confi rmed the presence of some microfossils reported by božičević et al. (1965). within recrystallized bioclastic-skeletal-lithoclastic grainstones (fig. 10) biogenic debris mostly made up of bioclasts of sea urchins, red algae, mollusc shells and tests of benthic foraminifera was discovered. among the latter, the most abundant are elphidium sp. (including elphidium crispum), followed by asterigerinata sp., melonis sp., heterolepa sp., gyroidinoides sp., ammonia sp., neoeponides sp., etc). e. crispum occurs, in the mediterranean region, in miocene sediments (agip, 1982). in a preliminary study of the fossil content of the salamandrija unit, božičević et al. (1965) reported, besides casts and fragments of molluscs, fragments of calcareous algae, and recrystallized globigerinids, a number of benthic foraminifera including robulus sp., amphistegina sp., nonion granosum, n. soldanii, rotalia beccarii, elphidium cripum and ostracod species cythereis tricostata. according to božiče vić et al. (1965), this fossil assemblage indicates a general neogene age, similar to a marine pliocene assemblage found in southern apulia. however, the abundance of elphidium sp. is suggestive of a miocene age, and, in any case, as a detrital limestone made up of reworked bioand lithoclasts, the fossil assemblage of the salamandrija unit is not conducive to precise age determination. the foraminiferal association indicates an inner shelf environment (cf. boltovskoy & wright, 1976). božičević et al. (1965) suggest a coastal sedimentary environment based on the abundance of amphistegina sp. undefi ned subangular lithoclasts of older rocks are also present, including micritic limestones containing calpionellids (tintinnids). these redeposited subangular lithoclasts suggest that older rocks (including mesozoic deeper-water micritic limestones) were deformed and exposed during sedimentation of the salamandrija unit. 3.3.2. strontium isotopes of the salamandrija unit as an independent method to determinate age for the salamandrija unit, the 87sr/86sr composition of a bulk biocalcarenite sample from the salamandrija quarry pit were analysed. (location 6 on fig. 2), along with the shells of two modern intertidal gastropods, natica millepunctata and patella coerulea, col lect ed at the island of hvar and representing the present stron tium isotopic composition of adriatic seawater. in addition, a sample of pelagosite, which represents a bioaragonite related to the cyanobacterial activity in the supratidal zone (see section 4.3.), and a sample of dolomite from the lanterna unit a were also analysed. analysis was undertaken at the berkeley institute for isotope geochemistry, using sample preparation and an analytical procedure similar to that described by depaolo & ingram (1985). the results are shown in table 2, and plotted in fig. 11 against the curve of seawater strontium composition from the permian to recent (mcarthur et al., 2001). the composition of the lanterna unit a dolomite resulted in an ambiguous age determination, because of strong diagenetic alteration of the parent rock. the 87sr/86sr value of 0.709072 from the salamandrija biocalcarenites provides a minimum age of about 9 ma (i.e. lower tortonian). 3.3.3. age of the salamandrija unit salamandrija biocalcarenites contain a wealth of microfossils and skeletal fragments of shallow-marine benthic forafi gu re 10: microfacies and microfossils in the miocene biocalcarenite of the salamandrija unit (sample pal–13, location 6 on fig. 2). scale bar 0.5 mm. geologia croatica 62/2geologia croatica 86 minifera, which indicate a broadly neogene age (section 3.3.1., fig. 10). combining the biostratigraphic data with the chemostratigraphy (section 3.3.2.; fig. 11) a broadly miocene age is proposed here for the salamandrija unit. 3.4. talus units and rock falls the stratigraphic succession making up the bedrock of velika palagruža is covered, particularly in the central part of the island, by loose or locally cemented talus, including breccia, rock-fall boulders, and soil. in the area of stara vlaka, a wedge of dip-slope, coarse, poorly cemented detritus covers up the dolomites of the lanterna unit b. a cross section of the wedge and the underlying bedrock is exposed in the stara vlaka cove (fig. 6a), offering the opportunity to determine the relationship between the cover and the underlying bedrock. here, the dolomitic breccias of the lanterna unit b are strongly tectonized, and displaced by the wnw– ese striking oblique-slip fault, which puts them in contact with the equally tectonized žalo unit (fig. 6b). the fault as well as the contact between the žalo unit and the lanterna unit a is capped by the detrital wedge, which clearly dips downslope toward the ne. the wedge is composed of layers of poorly cemented dolomite breccia resting on top of fi ner, reddish debris, probably representing a lateritic soil. near the contact with the underlying dolomite bedrock, at 13 m asl, a deposit of rounded pebbles suspended in a reddish sandy matrix (fig. 12a) occurs. in between the pebbles, rare fragments of bivalve shells and pebbles showing the typical superfi cial texture produced by perforating algae suggest a palaeobeach depositional environment. one pebble we collected is perforated by a lithodomus burrow, which still contains the original bivalve shell (fig. 12b). fi gu re 11: plot of the 87sr/86sr composition of samples from the lanterna unit a (dolomite), the salamandrija unit (biocalcarenite), pelagosite (bioaragonite), and modern adriatic gastropod shells compared to the permian to present seawater 87sr/86sr curve of mcarthur et al., 2001. table 2: strontium isotope ratios of the palagruža (plg) samples: lanterna unit a dolomite (cliff near picokare, fig. 2), salamandrija unit biocalcarenite (locality 6 on fig. 2) and pelagosite sample (cliff near picokare, fig. 2) compared with modern mollusc shells from the adriatic sea (island of hvar – hva) sample material formation age 87sr/86sr error ± plg/05-4 d dolomite lanterna unit a late triassic (?) 0.707490 0.000008 plg/05-10 l limestone salamandrija unit late miocene 0.709072 0.000010 plg/05-4 p aragonite pelagosite holocene 0.709232 0.000010 hva/07 nat calcite natica shell present 0.709221 0.000009 hva/07 pat calcite patella shell present 0.709235 0.000008 fi gu re 12: a) outcrop of the pebbly palaeobeach of stara vlaka: b) a rounded pebble showing the surface perforated by burrowing algae and lithodomus. a b korbar et al.: geologic reconnaissance of the island of velika palagruža (central adriatic, croatia) geologia croatica 87 it is uncertain whether this deposit represents the remnant of a quaternary palaeobeach or an older deposit formed during a miocene transgression or pliocene(?) to quaternary marine regressions (i.e., during the emergence of the island). as for the bedded talus, it appears that it formed in recent times after the emersion of the island, and it does not represent a sedimentary continuation of the salamandrija unit. a similar talus exposure, which suggests a post-mioce ne, post-deformational talus deposit, is observed on the west side of the picokare ravine (see fig. 4a). here the poorly cement ed breccia layers dip south, thus representing a talus slope with a bedding direction essentially perpendicular to the salamandrija unit and the stara vlaka talus wedge. it is worth mentioning that just below the saddle between salamandrija and the lighthouse peak, at about 50 m asl at the head of the picokare ravine, we found some sparse ro und ed pebbles, which may represent yet another, older paleobeach deposit. the slope on the south side of salamandija, between žalo and picokare, is littered by loose rock waste and boulders, some of which are so large that they may in fact represent bedrock remnants of a strongly eroded cliff topography. it is also to be noted that, it has been reported that catastrophic rock falls occurred in very recent times (forenbaher & kaiser, 2005). 4. neotectonics and related features the island of velika palagruža can be described as a vertical topographic feature, in which the bedrock has been emerging from the sea in response to active tectonics, and is affected by marine erosion. in section 2 we reviewed the present seismotectonic situation of the central adriatic, which places palagruža near the emergence of a large, seismically active thrust fault (bennett et al. 2008), and/or in an area where wrench tectonics and salt diapirism causes uplifting (e.g. grandić et al., 2002; geletti et al., 2008). while surveying the island in recent years, several features were discovered, which testify to the recent uplifting of the island. these are fl at areas (marine straths), palaeobeach deposits, and pelagosite, all occurring at different elevations throughout the island. 4.1. marine straths there are only few places where the topography is fl at at palagruža, which contrasts with the otherwise vertical topography of the island. these areas may represent marine straths (see fig. 2 for locations). of course, in this tiny island there are no extensive fl at surfaces that may strictly be defi ned as a marine strath or peneplain. thus, we use here the term of marine strath in a general sense, indicating a fl at and nearly horizontal erosional surface cutting across steeply dipping bedrock layers. one such marine strath is found at about 75 m asl, just above the biljovka cove (figs. 6a and 13a). another possible case of marine strath is represented by salamandrija, which is the largest fl at area of the island at about 60 m asl, and, in fact, this has been the site of human settlements since the early neolithic (forenbaher & kaiser, 2005). similarly, the archaeological site of jonkova njiva (about 50 m asl) on the eastern end of the island, and a small fl at area at about the same elevation on the westernmost point of the island may also be considered remnants of fl at erosional surfaces. finally, the rocky promontory composed of dolomite breccia of the lanterna unit b, which delimits the northern side of stara vlaka cove, is also cut by a fl at and nearly horizontal surface, at about 13 m asl (fig. 13b). this plateau is now covered in part by large rock-fall boulders, but in its inland part is overlain by the palaeobeach deposit. 4.2. palaeobeach deposits one palaeobeach deposit made up of rounded pebbles is described in section 3.4. (fig. 12a). a relatively conspicuous beach deposit is found at the western foot of the picokare ravine resting at about 6 m asl, and consisting of rounded pebbles, cobbles, and boulders (up to 40 cm in diameter) free of any matrix (fig. 14). some pebbles exhibit a perforated surface possibly caused by burrowing algae or lithophagous bivalves, but no shells, nor encrusting algal remains have been found so far. a deposit of rounded pebbles was observed fi lling a ledge on the vertical sea cliff just above the palaeobeach deposit of picokare, at about 13 m asl (fig. 14). although the boulders could be deposited 6 m asl from the recent shoreline by gigantic waves under specifi c hydrofi gu re 13: marine straths a) at 75 m above sea level above the biljovka cove, and b) making up the northern spur of stara vlaka cove. a b geologia croatica 62/2geologia croatica 88 dynamic regimes, the deposit was still interpreted as a remnant of a palaeobeach, since in the footwall of the cliff pebbly beach deposits have not been observed. thus, the pala eobeach also indicates recent uplifting of the island. unfortunately there are no means to determine an age for these palaeobeach deposits due to the absence of fossil remains. a more thorough survey of the cliffs around the lighthouse peak may reveal other deposits of this kind at different elevations, and chances are that fossil remains of sea molluscs can be found, providing material for radioisotopic dating. 4.3. pelagosite further evidence for the recent tectonic uplifting of palagruža comes from black mineral incrustations with a vitreous lustre resembling tar, which covers, in irregular patches, the rocky coast of the island from just above the tide line up to 13 m asl (fig. 15a). this strange substance was fi rst reported by marchesetti (1876), and, one year later, it was nam ed “pelagosite” (from pelagosa, the latin name of palagruža) by stossich (1877). the reports by marchesetti and stossich were followed by 50 years of debate in the international scientifi c community about the nature and origin of this strange mineral (e.g. cloëz, 1878; squinabol & ongaro, 1901; clerici, 1920). finally, onorato (1926) published a comprehensive paper on the morphological, mineralogical, physical, chemical, and microbiological characteristics of pelagosite samples from the tremiti islands, which are located some 75 km southwest of palagruža. pelagosite turned out to be pisolitic aragonite. it consists of pearl or mamellon-shaped objects with a concentric ring internal structure “similar to tree rings”, made of a pure aragonite, and solidly attached to the rocky substratum. according to onorato (1926), pelagosite is produced by “blue-green algae” (i.e., cyanobacteria) where the supralittoral rock is frequently wetted by sea aerosol. optical microscopy by montanari et al. (2007) confi rmed the pisolitic structure of pelagosite, as originally observed by onorato (1926), and showed that 2–3 μm thick alternating dark-light laminae are arranged rhythmically through mm-thick sections of pelagosite crusts (fig. 15b). thicker laminae contain submicron-size inclusions of organic matter (fig. 15c), including fragments of cyanobacterial cells (fig. 15d) similar to those observed by onorato (1926) in the tremiti pelagosite. by assuming that these laminae represent yearly accretions (just like the rings in a tree trunk), montanari et al. (2007) determined that their arrangement bears cyclicity with frequencies comparable to those of the periodic climate changes controlled by el nińo and the north atlantic oscillation (i.e., dry-wet/cold-warm meteorologic conditions alternating approximately every 3, 8, and 12 years). in a recent microbiological study of pelagosite samples from palagruža, macalady et al. (2008) confi rmed onorato’s conclusion of a biogenic origin for this aragonite and, through dna analysis of the organic fraction, they determined the presence of cells belonging to xenococcus (fig. 15d), a rare genus of cyanobacteria, and apparently a new species never described before. the fact that pelagosite apparently forms within a couple of metres above tide line, but today is found up to 13 m above sea level, suggests that palagruža is currently uplifting. the uplifting rate of the gargano promontory (apulia domain, fig. 1), estimated by mastronuzzi & sansò (2002) from u/th dating of bioherms and other paleo-sea level indicators, is 1.5 mm yr–1. in contrast, the coastal areas of ne adriatic (croatia) are presently under a regime of subsidence (benac et al., 2004; antonioli et al., 2007). the preliminary u/th dating of pelagosite from velika palagruža by montanari et al. (2007), yielded ages around 2200 years for samples collected between 3 and 4 m above sea level at picokare, and 6500 years for a sample from 6 m above sea level, suggesting that palagruža is uplifting at a rate comparable with the uplifting rate of the gargano promontory estimated by mastronuzzi & sansò (2002). this encourage further work to better evaluate the potential of this biomineral for assessing vertical tectonic movements of littoral environments. 5. summary and conclusions the tiny islands of the palagruža archipelago represent the only pieces of dry land exposed in the middle of the central adriatic sea. the outcrops offer the unique opportunity to study mesozoic and cenozoic deposits in the central part (mid-adriatic ridge) of the common adriatic foreland of the apenninic and dinaridic orogenic domains. our geological reconnaissance of the island of velika palagruža, the largest in the archipelago, allows us to assess some stratigraphic and tectonostructural characteristics, which were never described in the few geological reports available in accessible literature. velika palagruža is composed of four main sedimentary units. however, evidence that these units are in stratigraphic continuity is lacking, as they are all bounded by faults and discordances. fi gu re 14: subvertical bedding of the dolomites of the lanterna unit a exposed along the littoral cliff of picokare. pebbly palaeobeach deposits at the bottom of the picokare ravine (at about 6 m asl) and in a ledge of the cliff at about 13 m asl. korbar et al.: geologic reconnaissance of the island of velika palagruža (central adriatic, croatia) geologia croatica 89 the oldest unit recognized is formed of highly deformed siliciclastic (silt and clay) deposits containing gypsum and thin layers of stromatolitic limestones capped by a package of thin-bedded dolomite layers. palynomorphs contained in the clay at the base of this succession indicate a middle triassic age (ladinian). this unit, named žalo, represents a transitional fl uvial-to-shallow marine, occasionally evaporitic environment, typical of the middle triassic rifting phase of the adriatic microplate. the žalo unit is in discordant relationship with the young er lanterna unit of thick to medium-thick bedded dolomite and dolomite breccia, with or without chert. palynomorphs in a sample from the lanterna unit indicate a late triassic age. the lanterna unit is actually made up of two subunits recognizable for their different bedding thickness and style. unit a is characterized by thick and medium-thick layers of dolomite with chert, and unit b is characterized by massive dolomite breccia and thinto medium-thick dolomite layers devoid of chert. these two subunits are separated by a wnw – ese striking, subvertical, oblique-slip fault, which crosses the entire length of the island. the presence of well-bedded dolomite with chert and massive bodies of dolomite breccia suggests a transitional platform-to-basin depositional setting of an evolving adriatic basin domain. the lanterna unit dolomites are capped by biocalcarenites of the salamandrija unit, containing abundant microfossils, which, along with strontium isotope data, indicate a broadly miocene age. the biocalcarenites bedding alignment is highly discordant in respect to the underlying lanterna unit, although the actual contact between the two units is not visible because it is covered by talus. talus, landslide deposits, and humic soil make up the cover of the bedrock sedimentary succession of the island, and they represent the ultimate phase of emergence of the island, which probably occurred during pliocene? to quaternary times. the bedrock units of velika palagruža, each one displaced by faults and/or in diapiric contact to each other, and therefore not in stratigraphic continuity, represent just a few pieces of a large and complicated puzzle depicting the tectono-sedimentary evolution of the central adriatic basin. the almost perpendicular discordance (unconformity?) separating the salamandrija unit from the underlying triassic dolomites suggests a deformational phase preceding miocene marine deposition, perhaps a marine transgression over an already deformed and eroded dolomite massif. the wnw–ese striking subvertical oblique-slip fault that crosses the entire length of the island is probably still active. soft and strongly deformed ladinian siliciclastic-evaporitic žalo unit deposits occur along the fault, and may be related to diapirism. the central adriatic area is under an active seismic regime. recent uplifting of velika palagruža is shown by remnants of pebbly palaeobeach deposits, marine (erosional) fi gu re 15: a) pelagosite encrustations on the cliff near picokare at about 4 m above sea level; b) polished section of a pelagosite crust; c) thin section microphotograph (transmitted plain light) of a pelagosite crust from picokare showing a rhythmic microlaminar arrangement; d) a cell of cyanobacterium xenococcus extracted from pelagosite. a c b d geologia croatica 62/2geologia croatica 90 straths, and cyanobacterial supratidal encrustations (pelagosite) today found at various elevations above mean sea level. further detailed research on the structural geology, stratigraphy, micropalaeontology, and radioisotope geochronology will hopefully add detailed constraints in a more accurate reconstruction of the geologic and tectonic history of the palagruža archipelago. acknowledgement we would like to thank dr. branko kirigin, and his team of archaeologist researchers, for introducing us to palagruža and its marvels, and for supporting us with the logistics while surveying the island in several expeditions between 2005 and 2007. we thank ross mitchell, maxwell montanari, elisabetta ferroni, and markus fiebig for assistance during fi eldwork in several separate expeditions. we are also grateful to matteo d’amato and mislav for having given us a ride with their fast boats to the island in the expedition of october 2005. we like to thank simone galeotti and vincenzo picotti for a preliminary microfossil identifi cation of the salamandrija biocalcarenite. the sulphur analyses were undertaken at the university of leeds s isotope facility thanks to the help of rob newton. careful reviews by igor vlahović, simonetta cirilli, and mladen juračić, which signifi cantly improved the quality of the paper, are greatly acknowledged. this study was partly supported by the project “stratigraphy and geodynamic context of cretaceous deposits in the ne adriatic region” no. 181-1191152-2697 of the ministry of science, education and sports of the republic of croatia. references adloff, m.c., appia, c., doubinger, j. & lienhardt, m.j. (1984): zonation palynostratigraphiques dans les séries triasique traversées par de sondage le jura et le bas-dauphiné.– géol. fr., 1, 3–21. adloff, m.c., doubinger, j., massa, d. & vachard, d. (1986): trias de tripolitaine (lybie). nouvelles données biostratigraphiques et palynologiques. deuxičme partie. rev. inst. fr. pe., 41, 27–72. agip (1982): foraminiferi padani (terziario e quaternario).– atlante iconografi co e distribuzioni stratigrafi ca. 2nd edition, 52 pls. antonioli, f., anzidei, m., lambeck, k., auriemma, r., gaddi, d., furlani, s., orrů, p., solinas, e., gaspari, a., karinja, s., kovačić, v. & surace, l. (2007): sea-level change during the holocene in sardinia and in the northeastern adriatic (central mediterranean sea) from archaeological and geomorphological data.– quarter. sci. rev., 26, 2463–2486. doi: 10. 1016/j.quascirev.2007.06.022 batten, d.j. (2002): palynofacies and palaeoenvironmental interpretation.– in: jansonius, j. & mcgregor, d.c. (eds.), 2nd edition, palynology: principles and applications. aasp foundation, 3, 1011–1064. battaglia, m., murray, m.h., serpelloni, e. & bürgmann, r. (2004): the adriatic region: an independent microplate within the africa-eurasia collision zone.– geophy. res. lett., 31, l09605. doi:10.1029/2004gl019723. belak, m., koch, g., grgasović, t., vlahović, i., velić, i., sokač, b. & benček, đ. (2005): novi prinosi stratigrafi ji evaporitno-karbonatno-klasatično-vulkanogenog kompleksa komiškog zaljeva (otok vis, hrvatska) [new contribution to the stratigraphy of evaporitic-carbonate-clastic-volcanogenic complex of komiža bay (island of vis, croatia) – in croatian].– in: velić, i., vlahović, i. & biondić, r. (eds.): 3. hrvatski geološki kongres, (3rd croatian geological congress), opatija 29.09.–01.10. 2005., knjiga sažetaka (abstract book), hrvatski geološki institut – croatian geological survey, zagreb, 13–14. benac, č., juračić, m. & bakran-petricioli, t. (2004): submerged tidal notches in the rijeka bay ne adriatic sea: indicators of relative sea-level change and of recent tectonic movements.– mar. geol., 212, 21–33. doi: 10.1016/j.margeo.2004.09.002 bennett, r.a., hreinsdóttir, s., buble, g., bašić, t., bačić, ž., marjanović, m., casale, g., gendaszek, a. & cowan, d. (2008): eocene to present subduction of southern adria mantle lithosphere beneath the dinarides.– geology, 36/1, 3–6. doi: 10.1130/g24136a.1 bertinelli, a., ciarapica, g. & passeri, l. (2005): late triassic–jurassic basinal successions in molise and northern basilicata: the northernmost witness of the ionian ocean.– boll. soc. geol. it., 124, 177–188. bertotti, g, picotti, v., chilovi, c., fantoni, r., merlini, s. & mosconi, a. (2001): neogene to quaternary sedimentary basins in the south adriatic (central mediterranean): foredeeps and lithospheric buckling.– tectonics, 20/5, 771–787. besems, r.e. (1983): aspects of middle and late triassic palynology. 3. palynology of the hornos-siles formation (prebetic zone, province of jaén, southern spain) with additional information on the macroand microfaunas.– österreich. akad. wissensch. schriftenr. erdwissensch. komm., 5, 37–56. beutler, g., heunisch, c., luttpold, f.w., rettig, b. & röhling, h.-g. (1996): muschelkalk, keuper und lias am mittellandkanal bei sende (niedersachsen) und die regionale stellung des keupers.– geol. jb., a 145, 67–197. blendinger, e. (1988): palynostratigraphy of the late ladinian and carnian in the southern dolomites.– rev. palaeobot. palynol., 53, 329–348. doi: 10.1016/0034-6667(88)90038-3 bognar, a. (1995): geomorphological characteristics of the palagruža archipelago: in palagruža the pearl of the adriatic.– proceeding of the croatian meterological society, split, 87–95. boltovskoy, e. & wright, r. (1976): recent foraminifera.– the hague, dr. w. junk b.v. publishers, 515 p. bosellini, a. (2002): dinosaurs “re-write” the geodynamics of the eastern mediterranean and paleogeography of the apulia platform.– earth-sci. rev., 59/(1–4), 211–234. doi: 10.1016/s0012-8252(02) 00075-2 božičević, s., muldini-mamužić, s. & vrsalović-care vić, i. (1965): the sedimentary-petrographic and palaeontologic characteristics of the insular group of palagruža.– bull. acad. council sci. rsf yugoslavia, section a, zagreb, 10, 66–67. brack, p., rieber, h., nicora, a. & mundil, r. (2005): the global boundary stratotype section and point (gssp) of the ladinian stage (middle triassic) at bagolino (southern alps, northern italy) and its implication for the triassic time scale.– episodes, 28, 233–244. broglio loriga, c., cirilli, s., de zanche, v., di bari, d., gianolla, p., laghi, g.f., lowrie, w., manfrin, s., mastandrea, a., mietto, p., muttoni, g., neri, c., posenato, r., rechichi, m., rettori, r. & roghi, g. (1999): the prati di stuores/stuores wiesen section (dolomites, italy): a candidate global stratotype section and point for the base of the carnian stage.– riv. ital. paleontol. stratigr., 105, 37–78. brugman, w.a. (1986): palynological characterization of the upper scythian an anisian of the trans-danubian central range (hungary) and the vicentinian alps (italy).– unpubl, phd. thesis, university of utrecht, 95 p. brugman, w.a., veld, h., van buggenum, j.m., holshuijsen, r.p., boekelman, w.a., van den bergh, j.j., almekinders, m.p., poort, r.j., abbink, o.a. & d’engelbronner, e.r. (1988): palynological investigation within the triassic of the germanic basin of southern germany.– stuifmail, 6, 52–54. korbar et al.: geologic reconnaissance of the island of velika palagruža (central adriatic, croatia) geologia croatica 91 brugman, w.a., van bergen, p.r. & kerp, j.h.f. (1994): a quantitative approach to triassic palynology, the lettenkeuper of the germanic basin as an example.– in: traverse, a. (ed.): sedimentation of organic particles. univ. press cambridge, 409–429. brühwiler, t., hochuli, p.a., mundil, r., schatz, w. & brack, p. (2007): bioand chronostratigraphy of the middle triassic reifl ing formation of the westernmost northern calcareous alps.– swiss j. geosci., 100, 443–455. doi: 10.1007/s00015-0071240-2 channell, j.e.t., d’argenio, b. & horvath, f. (1979): adria, the african promontory, in mesozoic mediterranean palaeogeography.– earth-sci. rev., 15, 213–292. doi: 10.1016/0012-8252(79) 90083-7 chiarabba, c., jovane, l. & distefano, r. (2005): a new view of italian seismicity using 20 years of instrumental recordings.– tectonophys., 395, 251–268. doi: 10.1016/j.tecto.2004.09.013 clerici, e. (1920): pelagosite di canalgrande nell’inglesiente.– rendiconti dell’ccademia dei lincei, serie 5, fascicolo 11. cloëz, s. (1878): note sur une matičre minérale d’apparance vitreuse, qui se depose sur la roche littoral de la méditerranée.– bull. soc. géol. france, 6, 84. courtinat, b. & rio, m. (2004): the statistical analysis of palynofacies of the ladinian strata of the south east massif central, france (analyse statistique de palynofacičs des dépôts ladinien du se du massif central français).– rev. micropal., 47, 28–35. doi: 10.1016/ j.revmic.2004.01.002 cros, p. & doubigner, j. (1982): étude palynologiques de sédiments terrigčnes et pélagique du trias moyen des dolomites italiennes. relation avec la paléonvironnement.– sci. géol. bull., 35, 157–182. depaolo, d.j. & ingram, b.l. (1985): high-resolution stratigraphy with strontium isotopes.– science, 227, 938–941. doi: 10.1126/science.227.4689.938 eshet, y. (1990): paleozoic-mesozoic palynology of israel. 1. palynological aspects of the permo-triassic succession in the subsurface of israel.– geol. surv. isr. bull., 81, 1–57. forenbaher, s. & kaiser, t. (2005): palagruža i širenje zemljoradnje na jadranu (palagruža and the spread of the farming in the adriatic).– opvscula archaeologica, 29, 7–23. garcia gil, s. & diez, j.b. (2006): microfl ora of the “muschelkalk sedimentary cycle” in the nw iberian range, central spain.– 7th european palaeobotany-palynology conference, september 6–11, praque, program and abstracts, 47. geletti, r., del ben, a., busetti, m., ramella, r. & volpi, v. (2008): gas seeps linked to salt structures in the central adriatic sea.– basin res., 20, 473–487. doi: 10.1111/j.1365-2117. 2008.00373.x góczán, f. & oravecz-scheffer, a. (1993): the anisian/ladinian boundary in the transdanubian central range based on palynomorphs and foraminifers.– acta geol. hung., 36, 73–143. goričan, š., halamić, j., grgasović, t. & kolarjurkovšek, t. (2005): stratigraphic evolution of triassic arcbackarc system in northwestern croatia.– bull. soc. géol. france, 176, 3–22. doi: 10.2113/176.1.3 grandić, s., boromisa-balaš, e., šušterčić, m. (1997): exploration concept and characteristics of the stratigraphic and structural models of the dinarides in croatian offshore area.– nafta, 48/8–9, 249–266. grandić, s., biancone, m. & samaržija, j. (2002): geophysical and stratigraphic evidence of the adriatic triassic rift structures.– mem. soc. geol. it., 57, 315–325. grgasović, t. & sokač, b. (2003): review on fossil dasycladalean associations in the triassic of croatia.– acta micropalaeont. sinica, 20/1, 75–79. herak, m., herak, d. & markušić, s. (1996): revision of the earthquake catalogue and seismicity in croatia (1908–1992).– terra nova, 8, 86–96. doi: 10.1111/j.1365-3121.1996.tb00728.x heunisch, c. (1986): palynologie des unteren keupers in franken süd deutschlands.– palaeontographica b, 200, 33–110. heunisch, c. (1999): die bedeutung der palynologie für biostratigraphie und fazies in der germanischen trias.– in: hauschke, n. & wilde, v. (eds.): trias. eine ganz andere welt. mitteleuropa im frühen erdmittelalter. verlag dr. friedrich pfeil, münchen, 207–220. hochuli, p.a. & roghi, g. (2002): a palynological view on the anisian/ladinian boundary – new results from the seceda section (dolomites, northern italy).– i.u.g.s. commission on triassic stratigraphy, sts/igcp 467, field meeting, veszprém, hungary, 5–8 september 2002, geological institute of hungary, program and abstracts, 29–30. kirigin, b. & čače, s. (1998): archaeological evidence for the cult of diomedes in the adriatic.– hesperia, 9, 63–110. korolija, b., borović, i., grimani, i., marinčić, s., jagačić, t., magaš, n. & milanović, m. (1977): osnovna geološka karta sfrj 1:100 000. tumač za lastovo, korčulu i palagružu, k 33–46, k 33–47 i k 33–57. [basic geological map of sfry 1:100 000, geology of the lastovo, korčula and palagruža sheets – in croatian]. institut za geološka istraživanja, zagreb, savezni geolški zavod, beograd, 53 p. kovács, s., dosztály, l., góczán, f., oravecz-scheffer, a. & budai, t. (1994): the anisian-ladinian boundary in the balaton highland, hungary – a complex microbiostratigraphic approach.– albertiana, 14, 53–64. lučić, d., koch, g., foršek, g., maretić, s., balažboromisa, e., krizmanić, k., španić, d., mesić, i. & bubnić, j. (2003): lithofacies, palynofacies and organic facies of triassic evaporitic-carbonate succession: examples from croatian off-shore and syrian on-shore wells.– 22nd ias meeting of sedimentology, opatija. abstracts book, 111. macalady, j.l., montanari, a., bice, d.m., schaperdoth, i., maclean, l. & mariani, s. (2008): pelagosite climate record and the role of cyanobacterial biomineralization.– geochim. cosmochim. acta, 72/2, a579. marchesetti, c. (1876): descrizione dell’isola di pelagosa.– boll. soc. adriatic. sci. nat., 2, trieste, 283–306. mariani, s., mainiero, m., barchi, m., van der borg, k., vonhof, h. & montanari, a. (2007): use of speleologic data to evaluate holocene uplifting and tilting: an example from the frasassi anticline (northeastern apennines, italy).– earth planet. sci. lett., 257, 313–318. doi: 10.1016/j.epsl.2007.02.045 mastronuzzi, g. & sansň, p. (2002): holocene uplift rates and historical rapid sea-level changes at the gargano promontory, italy.– j. quarter. sci. 17, 593–606. doi:10.1002/jqs.720 mcarthur, j.m., howarth, r.j. & bailey, t.r. (2001): strontium isotope stratigraphy: lowess version 3: best fi t to the marine sr-isotope curve for 0–509 ma and accompanying look-up table for deriving numerical age.– j. geol., 109, 155–170. doi: 10.1086/319243 montanari, a., bice, d., druschel, g., mariani, s., marshall, c., olcott, a., sharp, w., tigue, t. & vucetić, m. (2007): rediscovering pelagosite: a mediterranean “microstromatolite” recording recent climate cycles.– geophys. res. abstr., 9, 01555, 2007, sref-id: 1607–7962/gra/egu2007-a-01555. onorato, e. (1926): sulla pelagosite delle isole tremiti nell’adriatico.– boll. soc. geolog. ital., 45, 17–31. orłowska-zwolińska, t. (1983): palinostratygrafi a epikontynentalnych osadów wyższego triasu w polsce (palynostratigraphy of the upper part of triassic epicontinental sediments in poland).– pr. inst. geol., 104, 1–89. geologia croatica 62/2geologia croatica 92 reitz, e. (1985): palynologie der trias in nordhessen und südniedersachsen.– geol. abh. hessen, 86, 1–36. ridente, d. & trincardi, f. (2006): active foreland deformation evidenced by shallow folds and faults affecting late quaternary shelf-slope deposits (adriatic sea, italy).– basin. res., 18, 171–188. roghi, g. (2004): palynological investigation in the carnian of the cave del predil are (julian alps, ne italy).– rev. palaeobot. palynol., 132, 1–35. doi:10.1016/j.revpalbo.2004.03.001 servizio geologico d’italia (2007): carta geologica d’italia 1:50.000 – catalogo delle formazioni quaderni.– serie iii – volume 7 – fascicolo vii – unitŕ tradizionali (2). scheuring, b. (1978): mikrofl oren aus den meridekalken des monte san giorgio (kanton tessin).– schweiz. paläont. abh., 100, 1–205. schulz, e. & heunisch, c. (2005): palynostratigraphische gliederungsmöglichkeiten des deutschen keupers.– in: beutler, g. (coord.), stratigraphie von deutschland iv, keuper. cour. forsch. inst. senckenberg, 253, 43–49. sokač, b., ščavničar, b. & velić, i. (1980): klastiti donjeg trijasa uz evaporite na otoku velika palagruža (središnji jadran) [the lower triassic clastics and the evaporites on the island of velika palagruža (central adriatic) – in croatian ].– geol. vjesnik, 32, 207–212. squinabol, s., & ongaro, g. (1901): sulla pelagosite. – riv. mineralog. cristallograf., 24, 44. stache, g. (1876): geologische notizen über die insel pelagosa.– verhandungen d. geol. reichsanst., 6, 123–127. stossich, m. (1877): sulla geologia e zoologia dell’isola di pelagosa.– boll. soc. adriatic. sci. nat., 3, trieste, 186. stur, d. (1874): tertiär petrefacte von der insel pelagosa in dalmatien, eingesendetvon herrn g. buchich in lesina.– verhandlungen d. geol. reichsanst., 391. šiftar, d. (1987): primjena izotopne analize sumpora u određivanju starosti anhidrita iz jadranskog evaporitskog područja [the use of sulfur isotope analysis in the age determination of the adriatic evaporitic area anhydrites – in croatian].– geol. vjesnik, 40, 65–74. tari, v. (2002): evolution of the northern and western dinarides: a tectonostratigraphic approach.– european geosciences union, stephan mueller special publication series, 1, 223–236. tyson, r.v. (1995): sedimentary organic matter. organic facies and palynofacies.– chapman and hall, 591 p. van bergen, p.f. & kerp, j.h.f. (1990): palynofacies and sedimentary environments of a triassic section in southern germany.– in: fermont, j.j. & weegink, j.w. (eds.): international symposium on organic petrology. med. rijks geol. dienst, 45, 23–39. van den bergh, j.j. (1987): aspects of middle and late triassic palynology. palynologocal investigation in the keuper (upper ladinian, karnian, norian and rhaetian) and lower jurassic (lias α1 + α2) of franken, se west-germany.– stuifmail, 5, 26–33. van der eem, j.g.l.a. (1983): aspects of middle and late triassic palynology. 6. palynological investigation in the ladinian and karnian of the western dolomites, italy.– rev. palaeobot. palynol., 39, 189–300. doi:10.1016/0034-6667(83)90016-7 visscher, h. & krystyn, l. (1978): aspects of late triassic palynology. 4. a palynological assemblage from the ammonoid-controled late karnian (tuvalian) sediments of sicily.– rev. palaeobot. palynol., 26/ 1–4, 93–113. doi:10.1016/0034-6667(78)90007-6 visscher, h. & brugman, w.a. (1981): ranges of selected palynomorphs in the alpine triassic of europe.– rev. palaeobot. palynol. 34, 115–128. doi: 10.1016/0034-6667(81)90069-5 visscher, h. & van der zwan, c.j. (1981): palynology of the circum-mediterranean triassic: phytogeographical and palaeoclimatological implications.– geol. rundsch., 70, 625–634. doi: 10. 1007/bf01822140 visscher, h., van houte, m., brugman, w.a. & poort, r.j. (1994): rejection of a carnian (late triassic) “pluvial event” in europe.– rev. palaeobot. palynol., 83, 217–226. doi: 10.1016/ 0034-6667(94)90070-1 vlahović, i., tišljar, j., velić, i., & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeog., palaeoclimatol., palaeoecol., 220/3–4, 333–360. doi: 10.1016/j.palaeo.2005.01.011 warrington, g. (2002): triassic spores and pollen.– in: jansonius, j. & mcgregor, d.c. (eds.), 2nd edition, palynology: principles and applications. aasp foundation, 2, 755–766. yaroshenko, o.p. & bash imam, i. (1995): age variability of palynomorph compositions of the middle and late triassic of syria and their relation to climate and facies.– stratigr. geo. correl., 3, 375–392. zappaterra, e. (1994): source rock distribution model of the periadriatic region.– aapg bull., 78/3, 333–354. manuscript received december 10, 2008 revised manuscript accepted may 25, 2009 available online june 19, 2009 korbar et al.: geologic reconnaissance of the island of velika palagruža (central adriatic, croatia) geologia croatica 93 appendix 1. list of autochthonous ladinian palynomorphs from the žalo unit claystones (sample pal–6, location 1 on fig. 2) spores calamospora tener (leschik, 1955) mädler, 1964a – 0.6% calamospora keuperiana mädler, 1964a – 0.6% todisporites minor couper, 1958 – 0.2% todisporites major couper, 1958 – 0.2% todisporites cinctus (maljawkina, 1964) orłowskazwolińska, 1971 – 0.4% deltoidospora minor (couper, 1953) pocock, 1970 – 0.2% concavisporites toralis (leschik, 1955) nilsson, 1958 – 0.8% concavisporites crassexinius nilsson, 1958 – 0.4% osmundacidites wellmanii couper, 1953 – 0.2% verrucosisporites morulae klaus, 1960 – 0.2% uvaesporites gadensis praehauser-enzenberg, 1970 – 1.2% porcellispora longdonensis (clarke, 1965) scheuring, 1970 – 0.4% anapiculatisporites spiniger (leschik, 1955) reinhardt, 1961 – 1.4% sellaspora rugoverrucata van der eem, 1983 – 0.2% kyrtomisporis ervei van der eem, 1983 – 1.4% (fig. 7/1) aratrisporites fi mbriatus (klaus, 1960) mädler, 1964a – 0.4% leschikisporis aduncus (leschik, 1955) potonié, 1958 emend. bharadwaj & singh, 1964 – 0.4% pollen enzonalasporites sp. patinasporites sp. heliosaccus dimorphus mädler, 1964b – 0.4% (fig. 7/4) cannanoropollis scheuringii brugman, 1986 – 1.4% (fig. 7/3) kuglerina meieri scheuring, 1978 – 0.8% doubingerispora fi lamentosa scheuring, 1978 – 0.2% (fig. 7/2) infernopollenites sulcatus (pautsch, 1958), scheuring, 1970 – 0.4% lunatisporites acutus leschik, 1955 emend. scheuring, 1970 – 4.2% (fig. 7/5) striatoabieites aytugii visscher, 1966 emend. scheuring,1970 – 0.8% (fig. 7/6) striatoabieites balmei klaus, 1964 emend. scheuring, 1978 – 4.6% triadispora plicata klaus, 1964 – 0.4% (fig. 7/7) triadispora crassa klaus, 1964 – 0.4% triadispora stabilis scheuring, 1970 emend. scheuring, 1978 – 0.4% triadispora verrucata (schulz, 1966) scheuring, 1970 – 1.2% podosporites amicus scheuring, 1970 emend. scheuring, 1978 – 1.2% brachysaccus neomundanus mädler, 1964a – 3.8% samaropollenites speciosus goubin, 1965 – 3.8% ovalipollis pseudoalatus (thiergart, 1949) schuurman, 1976 – 24.8% (fig. 7/8) staurosaccites quadrifi dus dolby, 1976 in dolby & balme, 1976 – 1.8% (fig. 7/9) vitreisporites pallidus (reissinger, 1950) nilsson, 1958 – 1.2% alisporites opii daugherty, 1941 emend. jansonius, 1971 – 2.4% falcisporites stabilis balme, 1970 – 0.8% sulcatisporites kraeuseli mädler, 1964a – 1.8% microcachryidites fastidioides (jansonius, 1962) klaus, 1964 – 7.4% haberkornia gudati scheuring, 1978 – 0.4% (fig. 7/10) haberkornia parva scheuring, 1978 – 0.4% praecirculina granifer (leschik, 1955) klaus, 1960 – 0.6% partitisporites verrucosa (praehauser-enzenberg, 1970) van der eem, 1983 – 0.8% duplicisporites granulatus leschik, 1955 – 0.4% duplicisporites verrucosus leschik, 1955 – 0.4% (fig. 7/11) camerosporites secatus leschik, 1955 emend. scheuring, 1978 – 15.8% (fig. 7/12) ephedripites primus klaus, 1963 – 0.4% cycadopites follicularis wilson & webster, 1946 – 0.8% aulisporites astigmosus (leschik, 1955) klaus, 1960 – 1.4% (fig. 7/13) prasynophycean algae leiosphaeridia sp. div. – 3.6% acritarcha veryhachium sp. 0.4% (fig. 7/14) micrhystridium sp. – 0.4% dictyotidium tenuiornatum eisenack, 1955 – 1.2% coenobial chlorophycean alga (chlorococcales) plaesiodictyon mosellanum wille, 1970 – 0.2% botryococcus sp. 0.2% geologia croatica 62/2geologia croatica 94 appendix 3. list of palynomorph groups according to their botanical affinity and ecological sensitivity a leschikisporis aduncus b calamospora spp., todisporites spp. c deltoidospora spp., concavisporites spp. d osmundacidites spp., verrucosisporites spp., anapiculatisporites spp. e uvaesporites spp., sellaspora spp. f kyrtomisporis ervei g aratrisporites spp. h cycadopites spp., aulisporites astigmosus, ephedripites primus i porcellispora longdonensis j vitreisporites pallidus, alisporites spp., k brachysaccus neomundanus, falcisporites stabilis, sulcatisporites kraeuseli, microcachryidites fastidioides, podosporites amicus, samaropollenites speciosus l ovalipollis pseudoalatus, staurosaccites quadrifi dus m infernopollenites spp., lunatisporites spp., striatoabi eites spp. n triadispora spp. o heliosaccus dimorphus, cannanoropollis scheuringii, kuglerina meieri, doubingerispora fi lamentosa p haberkornia gudati, haberkornia parva, praecirculina granifer, partitisporites spp., duplicisporites spp., camerosporites secatus q leiosphaeridia spp., r plaesiodictyon mosellanum, botryococcus spp. s veryhachium spp., micrhystridium spp., dictyotidium tenuiornatum appendix 2. list of reworked permian and lower triassic palynomorphs from the žalo unit claystones (sample pal–6, location 1 on fig. 2) spores cyclotriletes sp. endosporites papillatus jansonius, 1962 (fig. 7/17) densoisporites nejburgii (schulz, 1964) balme, 1970 (fig. 7/16) lundbladispora sp. kraeuselisporites sp. pollen cf. nuskoisporites sp. limitisporites sp. cf. lueckisporites virrkiae acritarcha micrhystridium sp. 1. introduction the tisza unit (fig. 1), a prominent part of which forms the objective of the present study, originated from the northern, european margin of tethys by mostly meso-alpine horizontal block (microplate) displacements (g é c z y , 1973; k o v á c s , 1982, kázmér & k o v á c s , 1985). the tisza unit in the sense of csont o s et al. (1992), which is equivalent to the tisia megaunit of szederkényi (1996), was one of the most stable blocks of the pannonian basin during the alpine tectonometamorphic cycle (árkai, 1991). in general, the first metamorphic event recorded in the tisza unit is characterized by barrow-type amphibolite facies regional metamorphism. this event was a clockwise p-t path from the variscan basement of the tisza unit, pannonian basin, hungary péter árkai , péter horváth and géza nagy overprinted by a low-pressure variscan event with grades varying from subgreenschist facies up to amphibolite facies with andalusite, closely related to granitoid magmatism (for reviews see lelkes-felvári & s a s s i , 1981; á r k a i , 1984; s z e d e r k é n y i , 1 9 8 4 ; árkai et al., 1985). having applied various thermobarometric methods á r k a i (1984) and á r k a i et al. (1985) calculated for gneisses, micaschists and intercalated amphibolites, peak conditions of 500-600°c and 5 00 -900 mpa for the first barrow-type amphibolite facies event. this event was supposed to be pre-variscan (l e lkes-felvári & sassi, 1981). á r k a i et al. (1985) elaborated alternative pre-variscan variscan polycyclic and variscan polyphase models. for the time being no isotopic ages older than variscan are available from the metamorphic basement of the tisza unit (lelkesf e l v á r i et al., 1996), which can be, at least partly explained by the intense variscan heating. the aim of the present paper is to provide thermobarometric data on the metamorphic history of a gneissamphibolite complex on the basis of new microstructural, mineral paragenetic and mineral chemical data and thermobarometric calculations, paying special attention to the chemical zoning of garnet porphyroblasts and their coexisting mineral assemblages (mineral inclusions and adjoining matrix minerals, respectively). 2. geologic outline and previous data the baksa-2 borehole, from which the investigated samples originated, is located at the se part of the tisza unit in se transdanubia, hungary (fig. 2). below a few tens of metres of neogene sedimentary cover, the elevated metamorphic basement of the görcsöny ridge (referred to gr in this study) is exposed, for a total thickness of over 1000 m, with near 100% core recovery (fig. 3). according to s z e d e r k é n y i (1976) the rocks of the gr suffered prograde “barrovian” regional metamorphism changing from the chlorite zone to the sillimanite zone. k o v á c h et al. (1985) described the metamorphic pile crosscut by the baksa-2 borehole, as the following downward succession: “upper marble”, chloritic two-mica gneiss, “lower marble” and garnetiferous two-mica gneiss and schist, intercalated with g eol . croat. 52/2 109 117 5 figs. 4 tabs. zagreb 1999 key words: gneiss, amphibolite, geothermobarometry, variscan regional metamorphism, tisza unit, pannonian basin, hungary. laboratory for geochemical research, hungarian academy of sciences, budaörsi út 45, h-1112 budapest, hungary. e-mail: arkai@sparc.core.hu abstract the polymetamorphic basement of the tisza unit forms a detached fragment of the variscan european foreland of the neotethyan realm. a clockwise evolution path of a gneiss-amphibolite complex of the tisza unit was reconstructed, investigating the polymetamorphic rocks of the borehole baksa-2, se transdanubia, hungary. the results obtained by microstructural and mineral paragenetic observations, mineral chemical analyses, and thermobarometric calculations define a p-t loop which suggests a complex variscan polyphase model rather than a pre-variscan variscan polycyclic one. the early part of the prograde path with kyanite is characterized by t-p conditions of 480±50°c and 470±70 mpa, respectively. the metamorphism reached its peak at 660±25°c and 750±50 mpa, when both kyanite and staurolite were stable. this metamorphic climax was followed by a nearly isothermal decompression to 440±2 0 mpa at 650±40°c. this event is marked by the presence of sillimanite and a second generation of garnet, and is closely related to the collisional variscan granitoid magmatism observed in considerable parts of the tisza unit. in amphibolites intercalated with gneisses, only this last event was preserved, providing t-p estimates of ca. 650-690°c / 400-500 mpa. the present paper provides the first demonstration of a continuous, clockwise p-t path from the metamorphic basement of the hungarian part of the tisza unit. 110 geologia croatica 52/2 amphibolites. according to kovách et al. (1985), the first metamorphic event that produced garnet, staurolite, kyanite and sillimanite in gneiss and micaschist, diopside in carbonate rocks and hornblende + a n d e s i n e labradorite in amphibolite occurred at 6306 50°c and 5 00-700 mpa. they obtained a whole rock rb/sr isochron age of 331±13 ma for these rocks that was interpreted as the age of this first metamorphic event. k o vác h et al. (1985) also defined a second phase of regional metamorphism that occurred at 400 4 10 ° c and 300-400 mpa at ca. 315±4 ma as deduced from a single rb/sr model age obtained on biotite. according fig. 1 tectonic sketch map of the pannonian basin (box indicates the study area, enlarged in figure 2). the -.-. -line shows the state boundary of hungary. fig. 2 a simplified pre-tertiary geological map of the görcsöny ridge and surrounding area after fülöp (1994), with the location of the baksa-2 borehole. legend: 1) metamorphic rocks of the görcsöny ridge; 2) metamorphic rocks of the somogy-d r áva basin; 3) gyód serpentinite; 4) carboniferous molasse; 5) permian molasse; 6-8) villány-type mesozoic; 6) triassic rocks; 7) jurassic rocks; 8) cretaceous rocks. to kovách et al. (1985), this event is demonstrated by the formation of a new biotite generation and partly, by a second generation of garnet, and was followed by a contact metamorphism restricted to the carbonate intercalations (pyroxene hornfels, hornblende hornfels) caused by aplite intrusions connected to the s-type, collisional variscan granitoid magmatism in the surrounding region (see also buda, 1981, 1985). 3. petrography in the metamorphic section of the baksa-2 borehole paragneisses and micaschists are predominant, intercalated with some amphibolites, minor calc-silicate rocks and marbles. for the present study characteristic paragneiss and amphibolite samples from various parts of the rock column were selected. the mineral abbrevations are after k r e t z (1983) except for amphibole (amph). the paragneisses consist of biotite+quartz +plagioc l a se + g a r n et + s i l l i m a n i te ± m u s c o v i te ± s t a u r o l i te ± k y a n i te ± k-feldspar and accessory apatite, zircon and tourmaline. two types of gneisses can be distinguished in thin-sections. type i gneisses contain large subhedral garnet porhpyroblasts with a few biotite and plagioclase inclusions. biotite and plagioclase are also present near the garnet rims with staurolite and kyanite. type ii gneisses also have garnet, but these garnets are much smaller and contain abundant inclusions of biotite, plagioclase and quartz. the matrix consists of fibrolitic sillimanite, biotite, muscovite, plagioclase and quartz. relic kyanite and staurolite can also be seen. b i o t i t e occurs in both types of gneiss, either as fine flakes in the matrix with fibrolitic s i l l i m a n i t e a g g r e gates defining the foliation, or as relic crystals wrapped by and pre-dating the foliation. the latter types of biotite also occur as inclusions in the large garnet porphyroblasts and rim the garnet blasts. fine-grained fibrolitic sillimanite is intergrown with biotite. m u s covite was found only in association with matrix biotite in type ii gneisses. biotite, muscovite and sillimanite are often folded together. the presence of large (generally >1 cm diameter) g a r n e t porphyroblasts is the most remarkable feature of type i gneisses. these subhedral, garnet grains display smooth surfaces, contain inclusions of biotite and plagioclase, and are sometimes rimmed by biotites (fig. 4a). the smaller garnets (max. 12 mm) found in type ii gneisses generally form poikiloblastic, irregularly shaped skeletal grains lacking any internal fabric. instead, they contain numerous inclusions of biotite and plagioclase (fig. 4b). plagioclase is usually xenoblastic or subhedral, and untwinned. kyan i t e and s t a u r o l i t e occur as relic porphyroblasts in biot i te s i l l i m a n i te -muscovite and/or quartz -p l a g i o c l a s e matrix in both types of gneisses. rarely, they reach the size of the garnet porphyroblasts in the type i gneisses, where they exhibit a rounded shape and occur in larger quantities than in type ii gneisses. sometimes small biotite inclusions are embedded in kyanite grains. a m p h i b o l i t e s exhibit lineation and show equigranular microstructure. their primary mineral assemblage contains amphibole + p l a g i o c l a se + quartz and subordinate epidote. a m p h i b o l e is the dominant phase forming prismatic or subhedral grains of 2-5 mm in length that are aligned with the lineation. p l a g i o c l a s e occurs as interstitial, xenoblastic grains, or forms veinlets with quartz. e p i d o t e forms small grains generally associated 111árkai, horváth & nagy: a clockwise p-t path from the variscan basement of the tisza unit... fig. 3 geologic profile of the baksa-2 borehole (modified after kovách et al., 1985). legend: 1) gneiss; 2) micaschist; 3) amphibolite; 4) marble; 5) aplite; 6) samples used for geothermobarometric calculations. 112 geologia croatica 52/2 with amphibole. the amphibolites contain some secondary k-feldspar and chlorite. 4. mineral chemistry chemical analyses of minerals were carried out using a jeol jxca-733 electron microprobe equipped with 3 wds, with a measuring programme of n a g y (1984) in the laboratory for geochemical research, hungarian academy of sciences. the measuring conditions were 15 kv, 30 na, defocused electron beam with a diameter of 5-10 µm, measuring time 5x5 s. matrix effects were corrected using the method of bence & a l b e e (1968). the following standards were used for quantitative analysis: orthoclase (k, al, si), synthetic glass (fe, mg, ca), spessartine (mn), rutile (ti) and albite (na). statistical (absolute) errors expressed as 1 σ are as follows: sio2: ±0.3, tio2: ±0.05, al2o3: ± 0 . 0 5 , feo: ± 0.2, mgo: ±0.1, mno: ±0.05, cao: ± 0 . 1 , na2o: ±0.03, and k2o: ±0.02 %. mineral compositions used in geothermobarometric calculations are given in tables 1-4. representative analyses and the structural formulae of biotite and muscovite are given in table 1. b i o t i t e occurs in all the metapelites investigated. its grains are unzoned, and their mg / ( m g + f e2 +) ratios range from 0.42 to 0.47. the ti content is between 0.22-0.3. biotites in the large garnet porphyroblasts of type i gneisses have the highest mgo (bt1). the highest ti was observed in biotites near the rim of the large garnet por phyroblasts (bt2). the composition of biotite in type ii gneisses is quite uniform regardless of whether the flakes are in the matrix or occur as inclusions in the garnets (bt3). inclusions of biotite in kyanite have the same composition as the biotites in the large garnet porphyroblasts. the composition of m u s c o v i t e flakes is homogenous. it contains 6.15 -6.2 si atoms p.f.u. the ga r n e t s are alm-rich in all rock types, independent of their textural position (table 2). the large garnet porphyroblasts (grt1) display composite zoning. the core is prp7alm76sps3grs14, while the rim is richer in prp and fig. 4 a) bse image of the large garnet (grt1) porphyroblast with biotite and plagioclase as inclusions and near the garnet; b) bse image of a grt2 porphyroblast with biotite and plagioclase occuring as inclusions and rimming the garnet. numbers refer to the mineral compositions given in tables 1-4, g1.1 = grt1core, g1.2 = grt1rim. bt1 bt2 bt3 mslocation grt1 core grt1 rim grt2 rim grt2 rim sio2 34.55 34.80 35.09 45.76 tio2 1.95 2.59 1.96 0.60 al 2o3 19.68 19.48 19.09 34.47 feo* 19.09 19.16 20.01 0.93 mno 0.10 0.10 0.13 0.04 mgo 8.87 8.85 8.53 0.59 cao 0.02 0.01 na2o 0.15 0.36 0.09 1.06 k2o 9.41 8.84 9.43 9.68 total 93.80 94.18 94.35 93.14 cation numbers on the basis of 22 oxygens si 5.344 5.346 5.415 6.204 ti 0.227 0.299 0.227 0.061 al 3.587 3.527 3.472 5.508 fe2+ 2.469 2.461 2.582 0.105 mn 0.013 0.013 0.017 0.004 mg 2.045 2.026 1.962 0.119 ca 0.003 0.001 na 0.045 0.107 0.027 0.279 k 1.857 1.732 1.856 1.674 total 15.586 15.511 15.562 13.956 mg# 0.45 0.45 0.43 0.53 al iv 2.656 2.654 2.585 1.796 alvi 0.931 0.872 0.887 3.712 t site 8.000 8.000 8.000 8.000 y site 5.685 5.672 5.676 4.002 z site 1.901 1.839 1.887 1.954 table 1 biotite and muscovite compositions used for p-t calculations. feo* = fe total. 113árkai, horváth & nagy: a clockwise p-t path from the variscan basement of the tisza unit... poorer in grs content (prp13alm74sps6grs7) with almost constant alm and sps. in comparison, the small garnet (grt2) shows a homogeneous chemical composition, with prp1 2a l m7 7s p s7g r s4. p l a g i o c l a s e coexisting with a core of grt1 is richer in an (an6 2), than plagioclase in contact with the rim of grt1 or with grt2 which are a n2 6 and an3 0, respectively (table 3). the composition of the plagioclase in amphibolites is rather homogeneous, showing an average an content of 33%. amphibole compositions are given in table 4. the calculations of cation numbers for a m p h i b o l e s f o l l o w the scheme of r o b i n s o n et al. (1982). using the classification of l e a k e et al. (1997) the analyzed amphiboles all belong to the calcic amphibole group, and within this fall into the tschermakite field (leake et al., 1997). 5. geothermobarometry temperatures and pressures for the paragneisses were calculated by the tweequ programme (version 2.02) of b e r m a n (1991) using the thermodynamic dataset of b e r m a n (1988), and activity models for garnet (b e r m a n , 1990), biotite (mcm u l l i n et al., 1991), muscovite (chatterjee & froese, 1 9 7 5 ) and plagioclase (fuhrman & lindsley, 1 9 8 8 ) . we also used the computer programme thermobarometry of spear (1993) with various calibrations of the garnet-biotite thermometer (ferry & spear, 1978; hodges & spear, 1982; kleemann & r e i n h a r d t , 1995), and the gasp barometer of newton & haselton (1981) and hodges & s p e a r (1982). in addition, the garnet-phengite thermometer of green & hellman (1982), the phengite barometry of massonne & schreyer ( 1 9 8 7 ) and the garnet-plagioclase-biotite-muscovite barometer of ghent & stout (1981) and hodges & crow l e y (1985) were applied to the gneiss sample containing muscovite. for the zoned garnet porphyroblasts the gibbs programme of s p e a r (1993) provided additional information on the p/t conditions for the garnet cores. for the amphibolites the thermobarometric methods of p l y u s n i n a (1982), holland & b l u n d y (1994) and g e r y a et al. (1997) were applied. results obtained by various methods are listed in table 5. in p a r a g n e i s s e s the composition of the core of the large garnet porphyroblasts (grt1), together with the biotite and plagioclase inclusions were used to obtain p-t data for the early part of the garnet growth, and the garnet rim composition with adjacent biotite and plagioclase for the conditions of the crystallization of the rim. on the basis of mineral paragenetic microstructural observations, kyanite was the stable aluminosilicate in these assemblages. garnet-biotite thermometry gave temperature estimates of 480±50°c, and gasp (garnet-kyanite-quartz-plagioclase) barometry gave pressure estimates of 460±50 mpa for the core using the tweequ programme. similar results were derived from the thermobarometry programme (470 4 90°c and 400 -550 mpa). using the gibbs progrt1 grt1 grt2location core rim rim sio2 36.77 36.90 37.48 tio2 0.16 0.01 0.08 al 2o3 21.01 21.55 20.87 feo* 34.18 33.36 33.69 mno 1.12 2.37 2.89 mgo 1.59 3.31 2.98 cao 5.50 2.37 1.66 na2o 0.06 0.03 0.01 k2o 0.07 total 100.39 99.97 99.64 cation numbers on the basis of 12 oxygens si 2.966 2.964 3.023 ti 0.010 0.010 0.004 al 1.997 2.040 1.984 fe2+ 2.306 2.241 2.272 mn 0.076 0.161 0.197 mg 0.191 0.396 0.358 ca 0.475 0.204 0.143 na 0.009 0.005 0.002 k 0.007 total 8.030 8.020 7.982 prp 6.37 13.20 12.11 alm 77.14 74.64 76.97 sps 2.55 5.37 6.67 grs 13.99 6.79 4.20 table 2 garnet compositions used for p-t calculations. feo* = fe total. plagioclase location grt1 grt1 grt2 amphicore rim rim bolite sio2 52.20 61.09 60.08 59.04 al 2o3 30.04 24.18 24.72 24.70 cao 12.79 5.43 6.40 6.96 na2o 4.30 8.52 8.11 7.61 k2o 0.06 0.10 0.15 0.15 total 99.39 99.32 99.46 98.46 cation numbers on the basis of 8 oxygens si 2.381 2.739 2.690 2.673 al 1.615 1.273 1.304 1.318 ca 0.625 0.260 0.307 0.338 na 0.380 0.738 0.704 0.668 k 0.003 0.006 0.009 0.009 total 5.004 5.006 5.014 5.006 an 61.96 25.90 30.11 33.28 ab 37.70 73.54 69.05 65.87 or 0.34 0.56 0.83 0.85 table 3 plagioclase compositions used for p-t calculations. 114 geologia croatica 52/2 gramme of spear (1993) we obtained 520°c and 400 mpa for the core. for the rim assemblage of grt1 6 60± 25°c and 750±50 mpa were obtained using tweequ, and 640 -6 80°c and 700 -800 mpa with thermobarometry. the chemically homogeneous, small garnet (grt2) with matrix and inclusion biotite and plagioclase, together with matrix muscovite and sillimanite, gave p-t estimates of 650±40°c and 440 ± 20 mpa with tweequ. for the same assemblage 630 6 50°c and 400 500 mpa were estimated with thermobarometry. using the phengite barometry of massone & schreyer (1987) with 6.2 si atoms p.f.u, similar pressure-ranges were obtained. however the pressures obtained with phengite barometry can only be interpreted as minimum pressures, because no k-feldspar was found in this assemblage. for a m p h i b o l i t e s three thermobarometric calibrations were used to decipher the p and/or t conditions of their formation. the results obtained by the methods of holland & blundy (1994) and g e r y a et al. (1997) are close to each other (680-690°c at 450 mpa, 6 50 -6 70°c at 400-500 mpa, respectively), while the earlier method of p l y u s n i n a (1982) gave significantly lower t (550°c) but similar p (550 mpa) values. 6. discussion figure 5 displays a model for joint interpretation of the results outlined above. microstructural and mineral paragenetic observations gave clear evidence for relative time-relations of the various mineral assemblages. these relations are indicated by the arrows in fig. 5. the detectable, first point in the prograde part of the p-t-relative time path was of medium-pressure type, with kyanite as index mineral. its calculated physical conditions were 480±50°c and 470±70 mpa. staurolite started to form in later stages of the prograde path. the metamorphism reached its peak conditions of 6 60±20°c, and 750±50 mpa, when both kyanite and staurolite were stable. this path, characterized by a simultaneous increase in temperature and pressure, was followed by a nearly isothermal decompression to 4 40±20 mpa at 650± 40°c. this event is marked by the presence of sillimanite, a new generation of small garnets and the formation of the observed foliation in the gneisses. it is likely to be closely related to the collisional variscan granitoid magmatism observed in the immediate vicinity of the studied occurrence and also in various parts of the tisza unit (buda, 1981, 1985). in amphibolites intercalated with gneisses, only this last event was preserved, providing less precise t-p estiamphibole sio2 42.47 42.89 42.86 tio2 0.57 0.84 0.69 al 2o3 13.29 12.40 12.62 feo* 16.07 15.77 16.01 mno 0.30 0.33 0.31 mgo 10.81 11.01 10.86 cao 11.44 11.72 11.59 na2o 1.56 1.55 1.49 k2o 0.71 0.55 0.76 total 97.22 97.06 97.19 cation numbers on the basis of 23 oxygens si 6.248 6.335 6.325 al iv 1.752 1.665 1.675 alvi 0.552 0.494 0.520 ti 0.063 0.093 0.077 fe3+ 0.889 0.727 0.767 mg 2.370 2.424 2.389 fe2+ 1.088 1.221 1.209 mn 0.037 0.041 0.038 ca 1.803 1.855 1.833 na 0.445 0.444 0.426 na 0.248 0.299 0.260 k 0.133 0.104 0.143 total 15.684 15.649 15.663 al total 2.304 2.159 2.195 table 4 amphibole compositions used for p-t calculations. feo* = fe total. assemblage temperature ( oc) pressure (mpa) paragneiss fs78 hs82 kr94 twq gh82 nh81 hs82 twq hc85 gs81 grt1core+ bt1+pl+ky 440-460 450-490 520-530 430-530 400-550 400-500 410-510 grt1rim+bt2+ pl +ky+st 630-670 640-670 600-630 635-685 700-820 660-770 700-800 grt2+bt3+ ms+ pl +sil 610-650 620-650 590-620 610-690 620-650 480-600 460-530 420-460 580-700 400-430 temperature ( oc) pressure (mpa) amphibolite p82 hb94 g97 p82 g97 amph+pl 550 680-690 650-670 550 400-500 table 5 p-t calculations on samples from the baksa-2 borehole. legend: fs78) ferry & spear (1978); hs82) hodges & spear (1982); kr94) kleemann & reinhardt (1995); twq) tweequ; gh82) green & hellman (1982); nh81) newton & haselton (1981); hc85) hodges & crowley (1985); gs81) ghent & stout (1981); p82) plyusnina (1982); hb94) holland & blundy (1994); g97) gerya et al. (1997). 115árkai, horváth & nagy: a clockwise p-t path from the variscan basement of the tisza unit... mates (ca. 650-690°c / 400-500 mpa) than the gneisses. as no prograde zonation was observed either in amphibole or in plagioclase of the amphibolites, one has to presume that the p-t results obtained from the amphibolites reflect the conditions of the last phase of metamorphism. the results obtained using the calibrations of holland & blundy (1994) and g e r y a et al. (1997) are in agreement with those obtained for the small garnet-bearing assemblage of the gneisses. as to the opinion of the present authors, the only isotopic data on the gneisses published by kovách et al. (1985) do not provide a reliable time-scale for the detailed metamorphic history, especially if the errors of age determinations are also taken into consideration. in addition, these dates are also in contradiction with the age of the granitoid magmatism (320 350 ma), that was summarised by buda (1985), who applied a wide series of isotopic methods to various minerals. therefore, the present authors think that the results of k o vác h et al. (1985) prove only the variscan age of the metamorphism in general, and demonstrate that no significant post-variscan heating occurred in the rocks investigated. in order to determine the age-sequence of the metamorphic events depicted in the present study, further isotope geochronological investigation of garnets and other accessory minerals is needed. nevertheless, the continuous changes in mineral chemistry, and especially the lack of any signs of retrogression (considerable cooling) between the metamorphic events, suggest that at present the complex polyphase variscan metamorphic model outlined by á r k a i (1984) and á r k a i et al. (1985) seems to be a more realistic working hypothesis than the polycyclic pre-variscan variscan model. 7. conclusions on the basis of microstructural, mineral paragenetic, mineral chemical and geothermobarometric investigations of gneisses and amphibolites characteristic of the basement of the tisza unit in se transdanubia, hungary, the metamorphic evolutionary path was reconstructed. using the chemical compositions of mineral inclusions and the core of large garnet porphyroblasts the pt conditions of the early prograde path were constrained (480±50°c and 470±70 mpa). the metamorphic peak conditions (660± 25°c, and 750±50 mpa) were similar or near to those calculated by á r k a i (1984) and á r k a i et al. (1985) for other parts of the basement of se transdanubia (somogy-dráva basin). the metamorphic climax was followed by isothermal decompression to 440±20 mpa at 650±40°c, most probably related to the variscan granitoid magmatism. considering the available isotope geochronological data, the new results can be best explained by a complex polyphase variscan metamorphic evolution model. acknowledgements the authors are indebted to prof. tibor szederkényi (józsef attila university, szeged, hungary) for providing selected rock samples from borehole baksa-2. the present paper forms a part of the metamorphic petrogenetic research program of p.á. (no. t022773) supported by the hungarian national research fund (otka), budapest. fig. 5 reconstructed pressure-temperature path of the gneiss-amphibolite complex from the baksa-2 borehole. boxes represent the estimated p-t conditions for the gneisses and circles for the amphibolites. al2s i o5 t r i p l e point is after h o l d a w a y (1971), the stability field of staurolite (grey area) is from spear (1993). legend: gb) garnet-biotite thermometry; gasp) garnet a l2s i o5q u a r tz -plagioclase barometry; gpmb) garn et p l a g i o c l a se m u s c o v i te biotite barometry; ap) amphibole plagioclase thermobarometry; g) gerya et al. (1997); hb) holland & blundy (1994); p) plyus n i n a (1982). numbers in subscript refer to the mineral compositions given in tables 1-4, g1.1 = grt1core, g1.2 = grt1rim. 116 geologia croatica 52/2 8. references á r k a i, p. (1984): polymetamorphism of the crystalline basement of the somogy-dráva basin (southwestern transdanubia, hungary).acta miner. petr. szeged, 26, 129-153. á r k a i, p. (1991): alpine regional metamorphism of the different tectonic domains in the hungarian part of the pannonian basin.in: b a u d, a., t h é l i n, p. & s t a m p f l i , g. (eds.): paleozoic geodynamic domains and their alpidic evolution in the tethys. igcp project no. 276, newsletter no. 2, mémoires de géologie (lausanne), 10, 5-13. á r k a i, p., nagy, g. & dobosi, g. (1985): polymetamorphic evolution of the south hungarian crystalline basement, pannonian basin: geothermometric and geobarometric data.acta geol. hung., 28, 165-190. bence, a.e. & albee, a. (1968): empirical correction factors for electron microanalysis of silicates.j. geol., 76, 382-403. berman, r.g. (1988): internally-consistent thermodynamic data for minerals in the system na2o-k2oc a o m g o f e o f e2o3a l2o3t i o2h2o c o2.j. petrol., 29, 445-522. berman, r.g. (1990): mixing properties of ca-mgfe-mn garnets.am. mineral., 75, 328-344. berman, r.g. (1991): thermobarometry using multi-equilibrium calculations. a new technique, with petrologic applications.can. mineral., 29, 835855. buda, gy. (1981): genesis of the hungarian granitoid rocks.acta geol. acad. sci. hung., 24, 309-318. b u d a, gy. (1985): genesis of collision type variscan granitoides in hungary, western carpathians and in the bohemian massif.unpublished phd thesis (in hung.), university of budapest, 148 p. chatterjee, n.d. & froese, f. (1975): a thermodynamic study of the pseudobinary join muscovite-paragonite in the system kalsi3o8n a a l si3o8-al2o3-sio2-h2o.am. mineral., 60, 985-993. csontos, l., nagymarosy, a., horvath, f. & kovac, m. (1992): tertiary evolution of the intra-carpathian area: a model.tectonophysics, 208, 221-241. ferry, j.m. & spear, f.s. (1978): experimental calibration of the partioning of fe and mg between biotite and garnet.contrib. mineral. petrol., 66, 113-117. fuhrman, m.l. & lindsley, d.h. (1988): ternary-feldspar modeling and thermometry.am. mineral., 73, 201-216. fülöp, j. (1994): the geology of hungary, paleozoic ii.monograph, akadémiai kiadó, budapest, 445 p. géczy, b. ( 1 9 7 3): the origin of the jurassic faunal provinces and the mediterranean plate tectonics.ann. univ. sci. budapest. r. eötvös nom. sect. geol., 16, 99-114. gerya, t.v., perchuk, l.l., triboulet, c., audren, c. & sez’ko, a.i. (1997): petrology of the tumanshet zonal metamorphic complex, eastern sayan.petrology, 5, 503-533. ghent, e.d. & stout, m.z. (1981): geobarometry and geothermometry of plagioclase-biotite-garnetmuscovite assemblages.contrib. mineral. petrol., 76, 92-97. green, t.h. & hellman, p.l. (1982): fe-mg partitioning between coexisting garnet and phengite at high pressure, and comments on a garnet-phengite geothermometer.lithos, 4, 253-266. hodges, k.v. & crowley, p.d. (1985): error estimation and empirical geothermobarometry for pelitic systems.am. mineral., 70, 702-709. hodges, k.v. & spear, f.s. (1982): geothermometry, geobarometry and the al2s i o5 triple point at mt. moosilauke, new hampshire.am. mineral., 67, 1118-1134. holdaway, m.j. (1971): stability of andalusite and the aluminium silicate phase diagram.amer. j. sci., 271, 97-131. holland, t.j.b. & blundy, j. (1994): non-ideal interactions in calcic amphiboles and their bearing on amphibole-plagioclase thermometry.contrib. mineral. petrol., 16, 433-447. kázmér, m. & kovács, s. (1985): permian paleogene paleogeography along the eastern part of the insubric periadriatic lineament system: evidence for the continental escape of the bakony drauzug unit.acta. geol. hung., 28, 71-84. kleemann, u. & reinhardt, j. (1995): garnetbiotite thermometry revisited: the effect of al vi and ti in biotite.eur. j. mineral., 6, 925-941. kovách, á., svingor, é. & szederkényi, t. (1985): rb-sr dating of basement rocks from the southern foreland of the mecsek mountains, southeastern transdanubia, hungary.acta miner. petr. szeged, 27, 51-56. kovács, s. ( 1 9 8 2): problems of the “pannonian median massif” and the plate tectonic concept. contributions based on the distribution of late paleozoic early mesozoic isopic zones.geol. rundschau, 71, 617-640. kretz, r. (1983): symbols for rock-forming minerals.am. mineral., 68, 277-279. 117árkai, horváth & nagy: a clockwise p-t path from the variscan basement of the tisza unit... leake, b.e., woolley, a.r., arps, c.e.s., birch, w.d., gilbert, m.c., grice, j.d., hawthorne, f.c., kato, a., kisch, h.j., krivovichev, v.g., linthout, k., laird, j., mandarino, j., maresch, w.v., nickel, e.h., rock, n.m.s., schumacher, j.c., smith d.c., stephenson, n.c.n., ungaretti, l., whitakerr, e.j.w. & youzhii, g. ( 1 9 9 7 ) : nomenclature of amphiboles: report of the subcommittee on amphiboles of the international mineralogical association commission on new minerals and mineral names.mineral. mag., 61, 295321. lelkes-felvári, gy. & sassi, f.p. ( 1 9 8 1): outlines of the pre-alpine metamorphism in hungary.in: karamata, s. & sassi, f.p. (eds.): igcp project no. 5 newsletter, 3, 89-99. lelkes-felvári, gy., árkai, p., sassi, f.p. & balogh, k. (1996): main features of the regional metamorphic events in hungary. a review.geol. carp., 47, 257-270. massonne, h.j. & schreyer, w. (1987): phengite barometry based on the limiting assemblage with k-feldspar, phlogopite, and quartz.contrib. mineral. petrol., 96, 212-224. mcmullin, d.w., berman, r.g. & greenwood, h.j. (1991): calibration of the sgam thermometer for pelitic rocks using data from equilibrium experiments and natural assemblages.can. mineral., 29, 889-908. nagy, g. (1984): computer programs for quantitative electron microprobe analysis developed for geological applications.proc. 8th eur. congr. on electron microscopy, eurem ’84, budapest, 1041-1042. newton, r.c. & haselton, h.t. (1981): thermodynamics of the garnet-plagioclase-al2s i o5quartz geobarometer.in: newton, r.c. ( e d . ) : thermodynamics of minerals and melts. springer verlag, new york, 131-147. plyusnina, l.p. (1982): geothermometry and geobarometry of plagioclase-hornblende bearing assemblages.contrib. mineral. petrol., 80, 140-146. robinson, p., spear, f.s., schumacher, j.c., laird, j., klein, c., evans, b.w. & doolan, b.l. (1982): phase relations of metamorphic amphiboles: natural occurrence and theory.in: veblen, d.r. & ribbe, p.h. (eds.): amphiboles: petrology and experimental phase relations. reviews in mineralogy, 9b, mineralogical society of america, 227 p. spear, f.s. (1993): metamorphic phase equilibria and pressure-temperature-time paths.monograph, mineralogical society of america, washington d.c., 799 p. szederkényi, t. (1976): barrow-type metamorphism in the crystalline basement of southeastern transdanubia.acta geol. hung., 13, 27-34. szederkényi, t. (1984): az alföld kristályos aljzata és földtani kapcsolatai (crystalline basement of the great plain and its geological connections).unpublished phd thesis (in hung.), university of szeged, 184 p. szederkényi, t. (1996): metamorphic formations and their correlation in the hungarian part of the tisia megaunit (tisia megaunit terrane).acta miner. petr. szeged, 37, 143-160. manuscript received june 17, 1999. revised manuscript accepted november 12, 1999. 118 geologia croatica 52/2 geo.cro.2-3-61-kb.pdf 251 � branko sokač and tonći grgasović ab stra ct in this paper a new species salpingoporella tari n.sp. is established, found in a sample of barremian intraclastic grainstone. it is similar to s. annulata (lorenz) and s. grudii (radoičić), but visibly more robust. it has few branches per whorl, and the whorls being spaced far apart. the branches are laterally compressed at their distal ends, therefore being vertically elongated. new fi nding of salpingoporella cemi (radoičić) gave the new data on the variability of the shape of its branches, and on the precise stratigraphic position of the investigated localities. besides, salpingoporella patruliusi bucur is illustrated, this being its fi rst fi nd outside monti apuseni (south carpathians) and its geographic range thus encompassing also the dinarides. also, a large observed number of specimens of salpingoporella muehlbergii (lorenz) with ramifi ed thallus makes that feature both its species-specifi c and generic characteristic. quite strongly varying values of various biometric parameters, depending on the position on the thallus in one and the same specimen, raises serious questions as to their reliability and usefulness as a distinguishing factor in comparing both the specimens of one and the same species and of species of the same genus. keywor ds: dasycladales, salpingoporella, taxonomy, biogeography, lower cretaceous, dinarides, croatia croatian geological survey, sachsova 2, hr-10000 zagreb, croatia; (tgrgasovic@hgi-cgs.hr) on some salpingoporella species from the lower cretaceous of dinaric karst geologia croatica 61/2–3 251–271 1 fig. 1 tab. 7 pls. zagreb 2008 geologia croaticageologia croatica � 1. introduction in the course of investigations carried out by the croatian geological survey within the frames of various scientifi c and economic assignments in the area of the dinaric karst in croatia, samples for micropalaeontological analyses are also being collected. sporadic fi nds of abundant algal remains enable detailed specialized research, directed to more detailed stratigraphic positioning and analysis, better knowledge of biogeographic distribution, grouping of characteristic fossil assemblages, and establishing new taxa or emendation of the existing ones, respectively. this is also the purpose of this paper. we shall analyse some species of the dasyclad genus salpingoporella: establish a new species s. tari, describe and illustrate s. cemi (radoičić) and s. patruliusi bucur, and report on abundant fi nds of s. muehlbergii showing branching thallus. 2. description of algal taxa salpingoporella cemi (radoičić, 1968) radoičić, 1975 (pls. i–ii; pl. iii, figs. 1–8) 1968 pianella cemi n. sp. – radoičić, p. 189, pls. 9–11 1975 salpingoporella cemi (radoičić) – radoičić, p. 277 2006 salpingoporella cemi (radoičić) – carras, conrad & radoičić, p. 469 (complete synonymy), pl. ii, fi gs. 1–5 the species was originally described as pianella cemi n. sp. (radoičić, 1968). later radoičić (1975) designated the lectotype and transferred species to the genus salpingoporella. this alga has not been known from the area of the dinaric karst in croatia, and with the new fi ndings in the limgeologia croatica geologia croatica 61/2–3 252 ska draga (west istria) and biokovo mt. (dalmatia) the knowledge of upper neokomian microfossil association in this area is improved. some new data can be added on the previous descriptions of this species. cylindrical, unramifi ed, thallus is characterized by thick walls built of mosaic calcite derived by heteroaxial transformation of, probably, primary aragonitic skeleton. along the margins of the skeleton tiny, short-prismatic, calcite crystals are developed, whereas the remainder of the skeleton is fi lled up with middleto coarse-grained mosaic calcite cement. skeletal walls are delineated with very thin micritic lining of constant thickness. inner surface of skeleton is even and smooth. outer surface of skeleton was originally, probably, also smooth, but in the thin sections available it is secondarily eroded and only fragmentarily preserved in individual sections (pl. i, fig. 2; pl. ii, figs. 4–6, 8). it is generally characterized by open pores of distally widened branches (pl. i, figs. 5, 7; pl. ii, figs. 4, 6). central cavity usually occupies 25–30% of the total diameter. salpingoporella cemi is characterized by simple, comparatively large, phloiophorous branches with visibly widened distal ends, arranged in clear whorls and with alternating position in consecutive whorls (pl. i, fig. 4). though being generally of the phloiophorous shape, when comparing the sections of several individuals, the branches show a variation in their shapes, due to either a more or less regular gradual widening towards the distal ends (pl. i, fig. 3; pl. ii, figs. 2, 6–7; pl. iii, figs. 2, 3, 5–7), or an abrupt widening in the distal third of their length (pl. i, figs. 7, 8; pl. ii, fig. 24; pl. iii, fig. 2) that may sometimes come nearer to the vesiculiferous type. in the relation to the longitudinal axis, the branches are subhorizontal or slightly directed upwards, as was already stated in original description of this species (radoičić, 1968). one confusing specimen from this article (radoičić, 1968, pl. ix, fi g. 6) suggest the articulation (annulation) of the skeleton, while particular branches suggest metaspondility (?), so it may be interpreted as species falsolikanella danilovae (radoičić). sporadic occurrence of rather unclear rounded structures within the distal widenings of the branches (pl. ii, figs. 8–9; pl. iii, figs. 1, 5) may indicate the existence of cysts, whereupon the species should belong to the cladosporous type of the dasycladal algae (family triploporellaceae). dimensions in mm (n = 26): outer thallus diameter (d) 0.92–1.68 inner thallus diameter (d) 0.34–0.64 relation d/d 0.243–0.452 length of branches (l) 0.30–0.54 proximal diameter of branches (pp) 0.05–0.10 distal diameter of branches (pd) 0.12–0.39 distance between neighboring whorls (h) 0.12–0.20 number of branches per whorl (w) 10–14 salpingoporella cemi (radoičić) seems to be less comon then other species of this genus. new fi ndings comprise few specimens from limska draga and island mljet, and large number of well preserved specimens in sample kj-8 from the biokovo mt. all these fi nds come from the same stratigraphic level: terminal part of the neocomian deposits. this conclusion is based upon the monitoring of occurrences and disappearances of particular species in the accompanying as semblage. biokovo mt. locality is an outcrop located on the cut-off of mountain road leading to sv. jure peak (1762 m), described in detail by sokač (2007). the sample with s. cemi contains also numerous humiella catenaeformis (radoičić) and clypeina? solkani conrad & radoičić (pl. iii, fig. 9), together with rare salpingoporella annulata (lorenz). this assemblage is also characterized by the fi rst occurrence of the signifi cant foraminiferal species campanelulla capuensis de castro, which has a fairly well defi ned upper hauterivian – lower barremian stratigraphical range. according to our present knowledge, whereas h. catenaeformis and s. annulata do not exceed the hauterivian-barremian boundary in the dinarides, the fi rst occurrence of c. capuensis falls into the upper hauterivian, and thus the position of the kj-8 sample may be reliably defi ned as upper hauterivian. an almost identical assemblage, lacking only h. catenaeformis (which, so far, does not seem to occur in the nw dinarides) but enriched with falsolikanella danilovae (radoičić) occurs in the limska draga samples (l-77 and l-78), just below a short lasting emersion which marks the neocomian-barremian boundary. at described localities fi ndings of s. cemi lie bellow the fi rst appearance of salpingoporella melitae radoičić. salpingoporella tari n. sp. (pl. iv) derivation of name: the species has been named after the cove and village tar in west istria, where the sample with that alga has been collected during a reconnaissance campaign. type locality: istria, south-southwest of the village tar, on the road toward the nova vas (fig. 1). geographic coordinates are: x = 5016.701 (λ=45°17’11“), y = 5391.911 (φ= 13°37’19“). the sample-yielding outcrops were situated in an excavation for water pipes along the road, but small isolated and kar stifi ed outcrops can also be found in the surroundings, scattered within plowed fi elds. outcrops are characterized by stromatolitic and grain-supported intra-pelsparitic limestones with algal fragments. the algal bearing microfacies is an intraclastic-algal grainstone. algae can be found also within the grains. the sedimentary environment may be interpreted as shallow subtidal with slow carbonate deposition. holotype: longitudinal-tangential section fi gured in pl. iv, fig. 3, thin section tar-1. isotypes are illustrated by other, variously oriented, sections, fi gured in the same plate (pl. iv). the type material is stored at the authors’ collection in the croatian geological survey. five thin sections have been made of one sample. diagnosis: alga has relatively robust cylindrical skeleton, made from mosaic calcite. it is characterised by pronouncedly spaced whorls of phloiophorous branches. branches are laterally compressed in distal part that resulted in their vertical elongation and makes vertical and horizontal cross-sections of branches signifi cantly different. in the horizontal cross -secgeologia croaticabranko sokač and tonći grgasović: on some salpingoporella species from the lower cretaceous of dinaric karst 253 tion, branches by their exit from the central cavity gradually and regularly widen. in longitudinal and parts of oblique sections, depends of the section plane, after the fi rst third or half of their length, branches more or less abruptly widen, attaining funnel-like shape. at the outer surface upper and lower edges of vertically elongated branches are in mutual contact that, in respect to the size of pores, favours destruction of the surface of calcareous envelope. dimensions in mm (n = 12): outer thallus diameter (d) 0.58–0.88 inner thallus diameter (d) 0.15–0.38 relation d/d 0.259–0.438 distance between neighbouring whorls (h) 0.24–0.40 length of branches (l) 0.24–0.30 proximal diameter of branches (pp) 0.04–0.10 distal diameter of branches in horizontal section (pdh) 0.10–0.12 distal diameter of branches in vertical section (pdv) 0.15–0.38 number of branches per whorl (w) 8–12 description: comparatively small cylindrical skeleton is built up of medium-grained mosaic calcite with a thin micritic margin. outer surface of skeleton is originally characterized by large cavities of branches’ pores, but is often additionally uneven due to destruction of partitions between distal parts of pores and diagenetic processes. the inner surface is delineated by an even, sometimes slightly wavy, thin line, perhaps indicating sporadic constrictions and swellings of the main cell (pl. iv, figs. 3–5, 9). beside the visible variation of the inner diameter (d), the difference between the smallest and the largest value of the d/d relation may be due to the varying outer diameter (d), as a result of a more or less progressing destruction of the outer surface. typical phloiophorous, comparatively large, branches are arranged into regular, clearly separated whorls (pl. iv, figs. 1, 3, 6, 9–10). going outwards from the main cell toward the outer part of the thallus, where they are laterally compressed and vertically elongated, the branches widen up irregularly. because of that, the shape of their pores within the skeleton is different in horizontal section from that in vertical section. in transverse sections, going outwards from the central cavity, they widen slowly, gradually, and in a relatively regular manner (plate iv, figs. 21–25). in longitudinal oblique sections, depending on the plane of sectioning, they appear generally funnel-shaped, and the abruptly widen after the fi rst third or about the half of their total length (pl. iv, figs. 3–4, 7, 12–13, 20). the arrangement of pores of the consecutive whorls, as well as their possible mutual touching on the outer surface, cannot be clearly seen. a few oblique sections passing into the tangential ones (pl. iv, figs. 9, 11, 15) reveal the true shape of the branches, showing the circular transverse section in their proximal part whereas more distally they become laterally com pressed and vertically elongated, giving, in transverse sections, a shape of a vertical rectangle with rounded edges. the branches in neighboring whorls probably stayed one above the other, very closely or even touching each other, as indicated in oblique (pl. iv, figs. 3–4, 7) and tangential sections (pl. iv, figs. 6, 9, 15). similarities and differences: s. tari n. sp. belongs to that group of not numerous salpingoporella species that are characterized by vertically fl attened and elongated distal part of the branches, due to their being horizontally compressed. by its general characteristics, s. tari n. sp. is most similar to s. annulata carozzi and s. grudii (radoičić). with regard to s. annulata (carozzi, 1953), the new species is considerably larger, contains less branches per whorl (8–12, most frequently 8–10), and has distinctly more spaced out whorls. the new species lacks pseudoannulation, menfi gu re 1: a) general position of the type locality of salpingoporella tari n. sp. b) simplifi ed topographic map of the type locality. arrow point to the outcrop of sample tar–1. geologia croatica geologia croatica 61/2–3 254 plate i salpingoporella cemi (radoičić, 1968) radoičić, 1975; x34 1 fragment of tangential section, kj-8/4. 2–9 diff erent oblique sections. fig. 2, kj-8/2; figs. 4–5, 7, kj-8/1; fig. 6, kj-8/10; fig. 8, kj-8/5; fig. 9, kj-8/9. geologia croaticabranko sokač and tonći grgasović: on some salpingoporella species from the lower cretaceous of dinaric karst 255 geologia croatica geologia croatica 61/2–3 256 plate ii salpingoporella cemi (radoičić, 1968) radoičić, 1975; x34 1–5, 9 diff erent oblique sections. fig. 1, kj-8/8; fig. 2, kj-8/13; fig. 3, kj-8/12; fig. 4, kj-8/7; fig. 5, kj-8/11; fig. 9, kj8/16. 6–8 transverse sections. figs. 6–7, kj-8/18; fig. 8, kj-8/17. geologia croaticabranko sokač and tonći grgasović: on some salpingoporella species from the lower cretaceous of dinaric karst 257 geologia croatica geologia croatica 61/2–3 258 plate iii 1–8 salpingoporella cemi (radoičić, 1968) radoičić, 1975; x34 1 fragment of tangential section, kj-8/15. 2–4, 7–8 diff erent oblique sections. figs. 2–3, kj-8/16; fig. 4, l-77/7; figs. 7–8, l-77. 5–6 transverse sections. fig. 5, l-77/3; fig. 6, l-77/2. 9 clypeina? solkani conrad & radoičić, 1971 9 oblique section, kj-8/12, x34. geologia croaticabranko sokač and tonći grgasović: on some salpingoporella species from the lower cretaceous of dinaric karst 259 geologia croatica geologia croatica 61/2–3 260 plate iv salpingoporella tari n.sp.; x32 1,7, 9–11, 13, 16–19 diff erent oblique sections. figs. 1, 9, 17–19, tar-1; fig. 4, 7, 11, 13, 16, tar-1/3; fig. 10, tar-1/4. 2–4 longitudinal-oblique sections. holotype on fig. 3, tar-1. fig. 2, tar-1/4, fig. 4, tar-1/3. 5, 8, 12, 20 longitudinal sections. fig. 5, tar-1/4; fig. 8, tar-1; fig. 12, tar-1/2; fig. 20, tar-1/1. 6, 14 oblique-tangential sections. fig. 6, tar-1/1; fig. 14, tar-1/3. 15 fragment of tangential section, tar-1. 21–25 transverse sections. fig. 21, tar-1/4, fig. 22, tar-1/1; figs. 23–24, tar-1/2; fig. 25, tar-1/13. geologia croaticabranko sokač and tonći grgasović: on some salpingoporella species from the lower cretaceous of dinaric karst 261 geologia croatica geologia croatica 61/2–3 262 tioned in s. annulata. in s. annulata, the branches are very thin in their proximal part, as distinct from s. tari in which they are larger and, in horizontal section, uniformly broaden toward outer ends. because of s. grudii being very similar to s. annulata (possible synonym), the differences to s. annulata apply also to s. grudii (radoičić, 1962). with regard to s. croatica sokač, which, according to our opinion, cannot be considered synonymous with s. annulata as proposed by carras et al. (2006), the new species differs by very different shape of the branches. in s. tari, the distal ends of the branches are laterally compressed and vertically elongated, whereas in s. croatica the branches widen relatively uniformly toward exterior, somewhat more strongly only in the very distal parts (sokač, 1992, pl. i, fi gs. 18, 21), thus giving a more or less circular shape of the pores in tangential sections (sokač, 1992, pl. ii, fi g. 1). there exists also some similarity in oblique and longitudinal sections between the new species and s. biokoviensis sokač & velić. the difference exists in the shape of the branches, which in s. biokoviensis gradually and uniformly become wider in both horizontal and vertical sections, resulting in more or less quadrangular pores in tangential sections (sokač & velić, 1980), as distinct from s. tari, where the pores are only laterally compressed, thus gradually widening only in transverse sections, and abruptly widen in transversal sections. there is a confusing similarity, but oly in cross sections, with clypeina? solkani conrad & radoičić, while in oblique and logitudinal sections the difference is obvious. clypeina? solkani has articulated thallus and uniformly widened branches, in contrary to s. tari n. sp. that has simple cylindrical thallus and pronounced widening and vertical elongation of the branches. stratigraphic position: salpingoporella tari n. sp. comes from a randomly collected sample, which, except for numerous variously oriented sections of that alga, did not contain any other fossil remains, which would possibly have enabled a direct determination of its stratigraphical position. therefore we have analysed the fossil contents of the samples coming from isolated and scattered neighboring outcrops, which, however, cannot give reliable indications of the precise stratigraphic position of the sample analysed. there are some outcrops of stromatolitic and pelsparitic limestones not very far apart that yielded salpingoporella melitae radoičić, followed by locally heavily limonitized skeletal biosparites and these, in turn, being probably overlain by bacinella biomicrites which, in the sequence, contain also rare palorbitolina lenticularis (blumenbach). generally, the distribution of outcrops in the surrounding area and their rather scarce fossil content indicate the statigraphic position of that species as being possibly upper barremian. in istria, the transition to the aptian is characterized by a change in depositional system, with sudden regional deepening of sedimentary environment and sedimentation of thick-bedded and massive bacinella-fl oatstones, known as “yellow istrian” (“giallo d’istria”) architectural-building stone (velić et al., 1989, 2003; vlahović et al., 2003). salpingoporella patruliusi bucur, 1985 (pl. v; pl. vi, figs. 1–4) 1985 salpingoporella patruliusi n. sp. – bucur, p. 81–84, text-fi g. 1, pls. i–iii 1992 salpingoporella patruliusi bucur, 1985 – bucur, p. 449–450, text-fi g. 1 1999 salpingoporella patruliusi bucur – bucur, pl. ii, fi gs. 1–10 2001 salpingoporella patruliusi bucur – pop & bucur, pl. viii, fi g. 9 2001 salpingoporella patruliusi bucur – bucur & cociuba, p. 122, pl. 2, fi gs. 1–3 2007 salpingoporella patruliusi bucur – sokač, p. 84, pl. iii, fi gs. 1–3 this species was validly described and well illustrated, accompanied also by a graphic reconstruction, by bucur (1985, text-fi g. 1, pls. i–iii,). a renewed description with illustrations has also been published by bucur (1992). according to the original diagnosis (bucur, 1985), the species is characterized by relatively large cylindrical thallus, unbranched and unsegmented, with a narrow stipe, and phloiophorous branches arranged in alternating whorls. the branches are tilted with respect to the stipe and are surrounded by a relatively thick calcareous sheath. in their distal portion the branches are compressed, showing a rhombic, less commonly polygonal outline. calcifi cation around branches gives an outline of relatively thick envelope bordered by a thin micritic line. terminal parts of branches are not calcifi ed. so far, this species has been known only from the region of monti apuseni (southern carpathians) and thus, this being its fi rst fi nd outside the area mentioned, it represent a broadening of its are of distribution into the dinarides. in our material, the species is present, though by not numerous sections, in an otherwise rich algal assemblage in the sample kj-18, which has already been mentioned several times previously (sokač, 2004, 2005; sokač & grgasović, 2004). the dinaridic specimens (pl. v; pl. vi, 1–4) do not show any new remarkable characteristics. the thick calcareous sheath, enveloping the branches as mentioned by bucur (1985), composed of sparite and surrounded by a darker line of micrite, is hardly distinguishable and present in only a few specimens (pl. v, fig. 4; pl. vi, fig. 4). one gain an impression, that this sporadically present feature, as a possible consequence of quicker or slower calcifi cation spreading out from the rim of the branch membrane into the space between the branches, is not always fully completed leaving the remaining space to be subsequently fi lled up by micrite. the here illustrated specimens from mt. biokovo are in general somewhat larger, thus having somewhat larger values of biometric parameters in relation to those from the type locality (table 1). these differences in dimensions appear not important and seem to be well within the presumed variation range, when comparing specimens coming from localities situated so far apart from each other. beside the sections that can be reliably ascribed to s. patruliusi bucur, we have noticed several transverse sections geologia croaticabranko sokač and tonći grgasović: on some salpingoporella species from the lower cretaceous of dinaric karst 263 (pl. vi, figs. 5–8) which, in spite of some similarities with s. patruliusi, clearly differ from it. because of their scarcity and poor preservation we found it useful to enumerate some of their characteristics similar to s. patruliusi: narrow central cavity in relation to relatively large value of the outer diameter, clearly euspondyle (verticillate) arrangement of phloiophorous branches, very clearly expressed distal broadening of the branches, two or three rows of pores in the same plane of section with their diameters increasing going towards the outer rim. such arrangement of pores, with their maximum widening in the outermost circle, which corresponds to one of the lower whorls, is indicative of small distance between neighboring whorls and oblique position of branches, declining from the longitudinal growth axis under an angle of 30–40° and possible downwards bending in the peripheral part. with regard to s. patruliusi, there are more branches per whorl, which, in the available sections, can reasonably be estimated at 20–30. based on the features defi ned and supposed above, these sections can be ascribed, with necessary caution, to an as yet undescribed salpingoporella form. in spite of several unknowns, illustrations of that species can perhaps be useful as being indicative of the stratigraphic position of deposits with such remains in cases of new fi nds without better stratigraphic indicators. stratigraphic position: in the original description (bucur, 1985), the stratigraphic position of s. patruliusi is defi ned as being in the lower level of the pachyodont limestone, whose total range is barremian – lower aptian. in a later report and illustration (pop & bucur, 2001), the species is mentioned in the assemblage whose stratigraphic position is more reliably defi ned by palaeodictyoconus arabicus as upper barremian. the stratigraphic position and lithological characteristics of the algal-bearing deposits which yielded the algal-rich sample kj-18 from mt. biokovo have been reported and discussed in earlier papers (sokač, 2004, 2005, 2007; sokač & grgasović, 2004; tišljar et al., 2002). according to all data available so far, based on the rich fossil assemblage from the same sample, this fi nd, too, can be defi ned as upper barremian. salpingoporella muehlbergii (lorenz, 1902) pia, 1918 (pl. vi, figs. 9–11; pl. vii) the type species of the genus salpingoporella, found at numerous localities in the perrimediterranean region, in the dinarides is regularly present in the more or less rich algal assemblage whose range is within the barremian. the renewed description of that species, along with the emendation of the genus salpingoporella, has been given by conrad (1970), and once more, very succinctly, by bassoullet et al. (1978). in those descriptions, an unramifi ed and unsegmented thallus was emphasized as one of the main characteristics. sokač (1996, pl. i, fi g. 6), however, fi gured one section of a branching thallus of that species, and several more branching thalli of salpingoporella dinarica radoičić, and, based on that, proposed an amendment of the generic diagnosis, including the ramifi ed thallus. carras et al. (2006), both in their amend ment of the generic diagnosis and in the description of s. muehlbergii (lorenz), not mentioned that feature. in discussing the generic diagnosis, they stated that the exceptionally observed ramifi ed thallus in s. dinarica and s. muehlbergii, among many normal specimens (cylindrical tubes), may be teratogenous or result of a wound. disregarding the frequency and the cause, the observed ramifying thallus in the type species, as a subsequently established feature, should be included in the generic characteristics. today it appears quite unbelievable that the fi rst fi nd of a ramifi ed thallus in the type species came only after its numerous fi nds and more than centennial presence in the literature and, moreover, to be recorded by just one section. therefore we continued to record its fi nds, directing our research onto samples exceptionally rich with its sections and trying to fi nd new and more numerous specimens with branched thallus. several new sections, though, admittedly, still not very numerous in relations to the number of thin sections available (250), were found and reported in the previously mentioned sample kj-18 (sokač, 2004, 2005; sokač & grgasović, 2004). the new sections show without any doubt the presence of ramifi ed thalli in s. muehlbergii and open the possibility of redefi ning the values of the biometric parameters and their reliability in the comparative analysis, which was the prime goal of this discussion anyway. dimensions in mm (n = 11): in the lower part of the thallus, below the branching: d = 0.53–1.06 d = 0.28–0.76 d/d =0.514–0.843 in the lower part of the branched parts of thallus: d’ = 0.36–0.76 d’ = 0.16–0.24 d/d = 0.230–0.555 the fact that a comparatively small number of visibly ramifi ed thalli has been observed, as well as their long-lasting absence from the literature, cannot be taken as a proof of their being an exceptionally rare feature in that alga, but, rather, as a result of random sectioning, representing always only one plane of section. in spite of a comparatively small number of suitable sections, in which the outer and inner diameters of both the unbranched and the branching part of the thallus can be measured in one specimen, the mentioned values are twice as large in the unramifi ed part of the thallus (d, d) than in the table 1: comparison of biometrical parameters of specimens s. patruliusi bucur originating from the type locality in monti apuseni and of those from mt. biokovo (n = 11). dimensions are in mm. locality l d d d/d h l l pl w α apuseni 5.12 1.10–2.30 0.11–0.24 0.10–0.24 0.22–0.28 0.56–1.00 0.16–0.31 0.040–0.78 7–9 25–35 biokovo 8.9 1.26–2.66 0.40–0.85 0.182–0.354 0.20–0.24 0.74–1.24 0.24–0.44 0.09–0.15 9–14 20–40 geologia croatica geologia croatica 61/2–3 264 plate v salpingoporella patruliusi bucur, 1985 1 tangential-longitudinal section. kj-18/1, x17. 2 tangential-oblique section. kj-18/39, x14. 3 longitudinal section. kj-18/150, x22. 4–6 oblique-tangential sections. fig. 4, kj-18/91; fig. 5, kj-18/57; fig. 6, kj-18/159; x22. geologia croaticabranko sokač and tonći grgasović: on some salpingoporella species from the lower cretaceous of dinaric karst 265 geologia croatica geologia croatica 61/2–3 266 plate vi 1–4 salpingoporella patruliusi bucur, 1985 1 oblique section. kj-18/62, x17 2–4 transverse sections. fig. 2, kj-18/39; fig. 3, kj-18/19; fig. 4, kj-18/160; x22 5–8 ?salpingoporella sp. 5–8 transverse sections. fig. 5, kj-18/1, x22; fig. 6, kj-18/1, x17; fig. 7, kj-18/28; x22; fig. 8, kj-18/30, x22 9–11 salpingoporella muehlbergii (lorenz) with ramifi ed thallus 9 oblique section. kj-18/30, x34 10–11 longitudinal sections of secondary branches of the thallus. fig. 10, kj-18/9; fig. 11, kj-18/5; x22. geologia croaticabranko sokač and tonći grgasović: on some salpingoporella species from the lower cretaceous of dinaric karst 267 geologia croatica geologia croatica 61/2–3 268 plate vii salpingoporella muehlbergii (lorenz, 1902) with ramifi ed thallus, x22 1–9 diff erent sections of ramifi ed thalus, partly only secondary branches of the thallus (figs. 5, 6). fig. 1, kj-18/18; fig. 2, kj-18/54; fig. 3–4, kj-18/1; fig. 5, kj-18/30; fig. 6, kj-18/5; fig. 7, kj-18/175; fig. 9, kj-18/28. geologia croaticabranko sokač and tonći grgasović: on some salpingoporella species from the lower cretaceous of dinaric karst 269 geologia croatica geologia croatica 61/2–3 270 ramifi ed part (d’, d’). this suggests the possibility that different dimensions of identically oriented sections in the same sample do not, at least partly, refl ect varying dimensions between different specimens, but are taken at different places in more-less equally large specimens. further on, the frequently encountered wildly differing d and d values of similarly oriented sections in the same sample makes us believe that ramifi ed thalli are in fact much more frequent than could be concluded from a few sections where the branching is clearly visible. an additional confusion into analysis and discussion of biometric parameters and their comparison is brought in by comparatively numerous sections with distinctly small values, which we suppose derive from top parts of the branches, in which, of course, their thinning towards the top is refl ected in both smaller d and d (or, to be more precise, d’ and d’) values and the reduced thickness of the calcareous envelope (sokač, 1996, pl. i, fi g. 4; this paper pl. vi, figs. 10–11, pl. vii, fig. 6), which, then, also gives different values for some other parameters (l, p). from all that has been mentioned above, it can be concluded that the application of comparative analysis of biometrical parameters in fossil dasyclad algae, especially in the genus salpingoporella, leaves open a lot of uncertainties and open questions and therefore requires caution in bringing out conclusions. acknowledgement the samples used for analysis in this paper were collected during geological investigations in western istria and south dalmatia. in the fi eld work, numerous colleagues were involved, to whom we express our thanks, particularly to ivo velić, who also helped us by identifying accompanying foraminiferal assemblages and to igor vlahović and josip tišljar. we are grateful for the fi nancial support that was obtained by the ministry of science and higher education of the republic of croatia through the project “microfossil assemblages in carbonate sediments of the karst dinarides”, and also by the national science foundation through the project “geologic map of the konavle area” that enabled us comparative analysis of the contemporaneous fossiliferous strata in konavle area. we are particularly thankful to the reviewers marc conrad and ivan gušić for their careful reading of the manuscript and useful suggestions, which greatly contributed to the fi nal version of this paper. references bassoullet, j.p., bernier, p., conrad, m.a., deloffre, r. & jaffrezo, m. (1978): les algues dasycladacées du jurassique et du crétacé. – géobios, mém. spéc. 2, 1–330. bucur, i.i. (1985): a new dasycladacean alga in the urgonian limestones from padurea craiului (apuseni mountains): salpingoporella patruliusi n. sp. – rev. roumaine geol. geograph. geophys., ser. geologie, 29, 81–84. bucur, i.i. (1992): revised description of some dasyclad species from the romanian lower cretaceous. – rev. paleobiol., 11/2, 447–46. bucur, i.i. (1999): lower cretaceous dasyclad algae from the padurea craiului massif (northern apuseni mountains, romania). – acta palaeont. romaniae, 2, 53–72. bucur, i.i. & cociuba, i. (2001): lower cretaceous algae of padurea craiului. – in: bucur i.i., filipescu s. & sasaran e. (eds.): algae and carbonate platforms in the western part of romania, field trip guide, 4th regional meeting of ifaa. cluj university press, cluj-napoca, 119–127. carras, n., conrad, m.a. & radoičić, r. (2006): salpingoporella, a common genus of mesozoic dasycladales (calcareous green algae). – rev. paléobiol., 25/2, 457–517. carrozi, a. (1953): découverte du genre salpingoporella dans le juras sique supérieur du grand saleve. – arch. sci. geneve, vii, 19– 324e. conrad, m. a. (1970): barremian and lower aptian dasycladaceae in the area surrounding geneva (switzerland). – geol. romana, ix, 63–100. lorenz, t. (1902): geologische studien im grenzbebiete zwischen helvetischer und ostalpiner facies. – ber. naturforsch. ges. freiburg breisgau, 12, 34–62. pia, j. (1918): dasycladaceae. – in: trauth, f. (ed.): das eozänvorkommen bei radstadt im pongau und seine beziehungen zu den gleichalterigen ablagerungen bei kirchberg am wechsel und wimpassing am leithagebirge. k. akad. wiss., 95, 171–278. pop, g. & bucur, i.i. (2001): upper jurassic and lower cretaceous sedimentary formations from the valcan mountains (south carpathians). – studia univ. babes-bolyai, series geologia, 46/2, 7–94. radoičić, r. (1962): o jednoj novoj gornjojurskoj dazikladacei: pianella grudii nov. gen., nov. sp. (sur une nouvelle dasycladacee du jurassique supérieur: pianella grudii nov. gen., nov. sp.). – vesnik, a, 20, 202–209. radoičić, r. (1968): likanella? danilovae spec. nov. i neke druge dazikladacee iz donje krede spoljašnjih dinarida (likanella? danilovae spec. nov. and some other lower cretaceous dasycladaceae from the outher dinarides). – vesnik (a), 26, 177–194. radoičić, r. (1975): linoporella buseri sp. nov. from the liassic of the julian alps (a preliminary report). – bull. sci. cons. acad. sci. arts rsf youg. sect. a: sci. nat. techn. médic., 20/9–10, 277–278. sokač, b. (1992): two new species of calcareous algae (dasycladaceae) from the upper dogger of southern dalmatia (croatia) (dvije nove vrste vapnenačkih alga (dasycladaceae) iz gornjeg dogera južne dalmacije (hrvatska)). – geol. croat., 45, 15–24. sokač, b. (1996): taxonomic review of some barremian and aptian calcareous algae (dasycladales) from the dinaric and adriatic karst regions of croatia. – geol. croat., 49/1, 1–79. sokač, b. (2004): on some peri-mediterranean lower cretaceous dasy clad species (calcareous algae; dasycladales) previously assigned to different genera. – geol. croat., 57/1, 15–53. sokač, b. (2005): linoporella vesiculifera n.sp., a new calcareous alga (dasycladales) from the upper barremian of mt. biokovo (karst dinarides, croatia). – geol. croat., 58/2, 119–131. sokač, b. (2007): stop-11 – upper hauterivian algae – south of mali troglav. – in: grgasović, t. & vlahović, i. (eds.): 9th international sympo sium on fossil algae – croatia 2007, field trip guidebook and ab stracts. croatian geological survey, zagreb, 79–81. sokač, b. & grgasović, t. (2004): megaporella nikleri n.sp., a new calcareous alga (dasycladales) from the upper barremian of mt. biokovo, croatia. – riv. ital. paleontol. stratigr., 110/3, 651–658. sokač, b. & velić, i. (1980): a new calcareous alga, salpingoporella biokoviensis n.sp. (dasycladaceae) from lower aptian deposits of mt. biokovo, dalmatia (south croatia). – geol. vjesnik, 31 (1979), 145–150. tišljar, j., vlahović, i., velić, i. & sokač, b. (2002): carbonate platform megafacies of the jurassic and cretaceous deposits of the karst dinarides. – geol. croat., 55/2,139-170. geologia croaticabranko sokač and tonći grgasović: on some salpingoporella species from the lower cretaceous of dinaric karst 271 velić, i., tišljar, j. & sokač, b. (1989): the variability of thicknesses of the barremian, aptian and albian carbonates as a consequence of changing depositional environments and emersions in western istra (croatia, yugoslavia). – mem. soc. geol. ital., 40, 209–218. velić, i., tišljar, j., vlahović, i., matičec, d. & bergant, s. (2003): evolution of the istrian part of the adriatic carbonate platform from the middle jurassic to the santonian and formation of the fl ysch basin during the eocene: main events an dregional comparison. – in: vlahović, i. & tišljar, j. (eds.): evolution of depositional environments from the palaeozoic to the quaternary in the karst dinarides and the pannonian basin. fieldtrip guidebook 22nd ias meeting of sedimentology, 3–17. vlahović, i., tišljar, j., velić, i., matičec, d., skelton, p.w., korbar, t. & fuček, l. (2003): main events recorded in the sedimentary succession of the adriatic carbonate platform from the oxfordian to the upper santonian in istria (croatia). – in: vlaho vić, i. & tišljar, j. (eds.): evolution of depositional environ ments from the palaeozoic to the quaternary in the karst dinarides and the pannonian basin. fieldtrip guidebook 22nd ias meeting of sedimentology, 19–56. manuscript received february 19, 2008 revised manuscript accepted may 19, 2008 tisljar et al.indd carbonate platform megafacies of the jurassic and cretaceous deposits of the karst dinarides josip tišljar1, igor vlahović2, ivo velić2 and branko sokač2 1. introduction platform carbonate deposits found along the ne adriatic coast, usually referred to as the “karst dinarides”, represent a belt approximately 700 km long and, (after tectonic reduction), 80–210 km wide. this huge carbonate body stretches from the julian alps along the border between italy and slovenia, through the western and central parts as well as the coastal area and adriatic islands of croatia, through the western and southern part of bosnia and herzegovina to se montenegro and nw albania (fig. 1). the entire area was characterised by the long-term (middle triassic to middle eocene, or in some areas, from carboniferous) existence of carbonate platform environments, resulting in a very thick sequence of deposits. after polšak (1965a), who suggested that “the most appropriate term for the entire depositional area with characteristics of carbonate sill (the old term for carbonate platform – auth. comm.) stretching from nw slovenia to montenegro would be adriatic zone”, the area of karst dinarides was treated by numerous authors as a united carbonate platform, although with different names. the most common terms were “carbonate shelf of dinarides” (jelaska, 1973), “platform of the outer dinarides” (grandić, 1974), “adriatic plate (“carbonate platform”)” (polšak, 1981), “carbonate platform of the outer dinarides” (tišljar, 1983), “mesozoic carbonate platform” (tišljar et al., 1983b), “dinaric carbonate platform” (ogorelec, 1987; dragičević & velić, 1994; buser, 1989), “adriatic–dinaric carbonate platform” (velić et al., 1987; gušić & jelaska, 1993), “adriatic–dinaridic carbonate platform” (pamić et al., 1998) and “adriatic carbonate platform” (gušić & jelaska, 1990). all these names are synonymes for a single carbonate platform without regard to the recent geotectonic situation. since the 2nd international symposium on the adriatic carbonate platform, which was held in 1991 in zadar, croatia (vlahović & velić (eds.), 1991), it seems that most of the authors refer to this carbonate platform as the adriatic carbonate platform. a second, smaller group of authors accepted the geotectonic concept of the dinarides according to herak (1986), considering the existence of several geologia croatica 55/2 139–170 7 figs. zagreb 2002 key words: carbonate platform facies, carbonate platform slope, carbonate debrite and turbidite, emersion, bauxite, dolomite, sabkha evaporite, synsedimentary tectonics, jurassic, cretaceous, adriatic carbonate platform, karst dinarides, offshore and coastal adriatic areas, croatia, slovenia, bosnia and herzegovina, montenegro. 1 university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, hr-10000 zagreb, croatia; e-mail: jtisljar@rgn.hr 2 institute of geology zagreb, sachsova 2, hr-10000 zagreb, croatia. abstract platform carbonate deposits of the karst dinarides area have a stratigraphic range from the middle triassic (or even carboniferous in some places) to the middle eocene, forming a belt nearly 700 km long and, (after reduction by younger tectonics) 80–210 km wide. besides their significant thickness (4500 to 8000 m) they are characterised by frequent lateral and vertical alternations of different facies, mostly associated with shallow marine environments. environments ranging from peritidal through low-energy shallow subtidal–lagoons, restricted inner platform shallows, high-energy tidal bars, beach and shoreface to reefal–perireefal predominate, but there are also carbonate slope deposits and those representing temporarily drowned platform facies and intraplatform troughs. the jurassic to cretaceous part of this carbonate succession has been subdivided into 19 megafacies units (9 for the jurassic and 10 for the cretaceous), the majority of which represent an inner part of the ancient adriatic carbonate platform. marginal parts of the platform are mostly buried, either by the recent adriatic sea along the sw margin, or younger deposits along the ne margin; at some localities such jurassic and cretaceous deposits are represented by debrites and/or carbonate turbidites. an additional short review of the overlying uppermost cretaceous and palaeogene deposits (4 megafacies units) enabled a better insight into the post-platform evolution. the very complex vertical and lateral alternation of different megafacies units, including emerged areas which were observed throughout the studied sequence in different parts of the karst dinarides, indicate the significant palaeogeographic dynamics of the region. this variability resulted from interaction of the global eustatic signal and local factors, including extensive organic production on the carbonate platform and synsedimentary tectonics controlled by the specific palaeogeographic position of the platform during its geological history. 140 geologia croatica 55/2 141tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... palaeogeographic units in the same area during the mesozoic. according to herak (1986, 1989, 1991, 1993) two carbonate platforms existed in the area of the karst dinarides from the late triassic to the eocene – the adriatic carbonate platform (adriaticum) and the dinaric carbonate platform (dinaricum), separated by a persistant deep-water interplatform trough (epiadriaticum). for more information on this concept see blašković (2001) and vlahović et al. (2002c – this vol.). however, in this paper we will not use any specific term for the carbonate platform on which most of the carbonate deposits originated – instead we will use the term karst dinarides. namely, the adriatic carbonate platform s.s. comprises deposits of a stratigraphic range from the upper lias to the end of cretaceous ? fig. 1 location map with schematic drawing of the mesozoic platform carbonate deposits of the karst dinarides region. z welllm-6 ". we111m-3 .0" welllm-4 well~ weliim-22b weill':, offshore well kollllljka -1 .,. study area: ". ". " . ". ". "'. ". "'. ". 20. ~. ... wa.t.m, central and southern istria northern istria ". so. 3d. •• 50. ". 50. ". 50. m. eastern istrla cic:arlja ml southern isbia well pula-1 brijunl adriatic aea (aiflihore wells jadran-86) adriatic aa. (offshore weill lfira more 1m 1 to 5) adriatic sea (afl'shore wells jadran j-15) island of susak. (well su-1) island ofpremuda (well pr-1) 1.landa of komati (well kale-1) v.1.bit mt. mali halen v.lsblt mt. kubus velebit mt. lifko cerja mazln brunj plllylce lakee suha klliijina dolenjska nanos ml hrullca ml logdka planota trnovski gozd 1ia . kar10vac area (mllflinlca.k duga reali) isbell velika kapala mi.sanj-ogulin profile 8d. gorki kotar piaiiikgomje jelenje lie . gorki kotar sknici area 81". gorki kotar ziobin iu'h 7 • nikiic ii • podgortca ii • ceunje 10.. dlnara mt. lob. kamelnlca mi. 11 • biokovo mt. 12 • trogirarea (well boraja-1) 13 • island of brae 14 • drvar area 15 • smelica mi. " " , .. 10' 100 , .. 19 " " 22 " " , .. '" "" ,., " " " " '" '" " 33 " platform carbonates . ..1 a mi banjaluka ar ... glamck! 8rea trebinja .i'm dubrovnlk area (siano zavaja profile) dubrovnlk area (oeojnlk glliipci profile) dubrovnlk area (konayoska brda proftl.) dubrovnik ..... (cerovac hum profile) island of l.astovo kupl'm area pokuplje bihafarea lamel, maovice vinodol ravnl kotarl (wells rk-1 to rk-4) wells nln (nln-1) island of olib (outcrops and well ol-1) island of 1st island of dugl otok (outcrops and well 00-1) island of hvar island of crea island of krk island of loiinj island of pag oi'fshore well koraljka-1 island of vis (via-1) island of korfula 50 bosnia and 100 kin i her egovina 35 • island of mljet sa • peljelac peninsula 37 • primolten area sa.. janj area 311b. jajeearea 3k. oonji beipelj area 3!1 • banjaluka area i 140 geologia croatica 55/2 141tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... (see discussion by dragičević & velić, 2002 and vlahović et al., 2002c in this vol.), and we will discuss also some older and younger deposits. carbonate platform deposits of the karst dinarides are, besides their significant thickness (4500–8000 m, 6000 m in average), characterised by frequent lateral and vertical alternations of different facies, mostly associated with shallow marine environments. environments ranging from peritidal through low-energy shallow subtidal – lagoons, restricted inner platform shallows, high-energy tidal bars, beach and shoreface to reefal–perireefal areas are the most common, but the succession also comprises deposits of carbonate slopes and temporarily drowned platform facies and intraplatform troughs. on the basis of their main sedimentological, lithological, biofacies and lithofacies characteristics, the deposits accumulated in this area from the early jurassic to eocene can be subdivided into several megafacies units characterised by their extensive occurrence, i.e. regional importance, regardless of their thickness. for subdivision of rock sequences into megafacies, the additional works of numerous other investigators were also consulted. unfortunately, it was commonly impossible to use data from older publications, because although information on stratigraphy, palaeontological composition and general lithology was provided elements needed for facies reinterpretation were lacking; therefore these papers were neither used nor cited. this paper deals with a several thousand metre thick sequence of deposits covering a huge area, and therefore only simplified typical geological columns are presented. for detailed sedimentological and stratigraphical interpretations and illustrations, interested readers should check the original literature cited in this paper. the lateral and vertical pattern of different megafacies units, their locations, thickness and duration of sedimentary environments resulting in their deposition provide significant information not only about conditions in the depositional area but also about synsedimentary tectonics and the palaeogeomorphological evolution of the carbonate platform. temporal and spatial correlation of the megafacies identified here document the main sedimentological and tectonic events in the area of the karst dinarides. additionally, these data provide important arguments for interpretation of the palaeogeography of the entire area during the jurassic and cretaceous (and palaeogene to a certain extent). 2. carbonate megafacies of the jurassic deposits jurassic carbonate deposits of the karst dinarides can be subdivided into 9 megafacies units (figs. 2–4): j–1: megafacies of peritidal micritic, fenestral and vadose limestones with interbeds of early-diagenetic dolomites and emersion breccia, emersions and occasional bauxites; j–2: megafacies of lagoonal and subtidal inner platform oncoid, pelletal and skeletal mudstones/wackestones; j–3: megafacies of bioturbated and late-diagenetically dolomitized “spotty limestones” – mudstones and wackestones deposited in isolated and restricted lagoon/deeper subtidal areas of the inner platform; j–4: megafacies of lithiotid and brachiopod lithosomes and tempestite coquinas of shallow subtidal and lagoonal regions of the inner platform; j–5: megafacies of ooid grainstones deposited in environments with agitated water and ooid bars; j–6: megafacies of skeletal and intraclastic grainstones/ rudstones deposited in shallows with agitated water; j–7: megafacies of peri-reefal bioclastic limestones (rudstones and grainstones) with hydrozoan, stromatoporoid and coral patch reefs and biostromes; j–8: megafacies of “limestones with cherts” (including “lemeš deposits”), deposited within intraplatform troughs with temporary or continuous connection to the open sea, and j–9: megafacies of late-diagenetic dolomites. 2.1. megafacies of peritidal micritic, fenestral and vadose limestones with interbeds of earlydiagenetic dolomites and emersion breccia, emersions and occasional bauxites (j–1) deposits of megafacies j–1, i.e. peritidal micritic, fenestral and vadose limestones with interbeds of earlydiagenetic dolomites and emersion breccia, emersions and occasional bauxites, are most common in the lower and middle lias, dogger, oxfordian, kimmeridgian and upper tithonian deposits (figs. 2–4). they are mostly composed of fenestral and/or vadose limestones (mudstones, pelletal and/or skeletal wackestones), with layers of llh-stromatolites and skeletal/pelletal packstones and grainstones, while black-pebble and tempestite breccias and early-diagenetic dolomites are infrequent (tišljar, 1976; tišljar & velić, 1991). at some localities, mostly within middle lias and tithonian sediments, deposits of this megafacies are characterised by numerous shallowing-upward cycles on a dmto m-scale. cycles ending with desiccation cracks, desiccation breccia or vadose features (“desiccation cycles” – tišljar et al., 1983a; “vadose rhythms” and “vadose cycles” – tišljar, 1983; tišljar & velić, 1993) are common. a very good example of these cycles was described from upper tithonian deposits in western istria (locality 1a on 142 geologia croatica 55/2 143tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... a: w it :::l 6b-c senj ogulin profile __ ~m=-egafacies units ~ j-9 ~ k-10 1 ~.,. ~ .,.1 j-8 u:: ] k-9b i:lfafl j-7 ~ ~ j-6 j-5 j-4 j-3 1 1 j-2 iiii j-1 triassic 1 1 t-3 [11';,1;1 '. :'. ,.'. cj 3 ~ k-9a k-8 k-6a k-6 k-5 k-4 k-3 k-2 142 geologia croatica 55/2 143tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... fig. 1), but similar deposits were also found in a penecontemporaneous succession in offshore wells in the northern adriatic (locality 2c, wells j–15/3, j–15/4, j–15/6, j–18/5; veseli, 1999). early-diagenetic dolomites without traces of evaporites, formed by early-diagenetic dolomitization of supratidal carbonate muds under a relatively humid climate have been found only as thin interbeds within peritidal limestones of liassic age, e.g. in the lika region near ličko cerje and mazin (localities 3c and 3d), and within tithonian subtidal algal “clypeina limestones” near slunj in central croatia (locality 4). emersion breccias with typical palaeokarstic features and stratigraphic hiatuses, with sequences characterised by reductions of several tens to several hundreds metre thick intervals, partly with bauxite (figs. 2–4) have been documented from various stratigraphic levels in different regions of the karst dinarides. a hiatus lasting from the middle lias to the kimmeridgian has been documented in trnovski gozd (nikler, 1978), the suha krajina in slovenia (locality 5a – buser, 1969; dozet, 1994), the karlovac environs in croatia (locality 6a – bukovac et al., 1974; šparica, 1981; dragičević & velić, 1994), western and central bosnia (šparica, 1981; mojičević et al., 1978; marinković & ahac, 1980; vujnović, 1980) and in montenegro west of nikšić (locality 7 – radoičić & vujisić, 1970), and north and northeast of podgorica (locality 8 – živaljević et al., 1971). upper jurassic hiatuses or shorter gaps with karstification and/or bauxite formation were determined in different regions of the karst dinarides, usually in a stratigraphic range from the oxfordian to the late tithonian. e.g., in slovenia important emersions occur mostly within kimmeridgian beds (buser et al., 1967; dozet & mišič, 1997) in the nanos mt. (locality 5c), near hrušica mt. (locality 5d), in logaška planota (locality 5e) and suha krajina (locality 5a). in croatia emersion in western istria (locality 1a) lasted from the latest oxfordian/earliest kimmeridgian to the late tithonian (velić & tišljar, 1988), on the biokovo mt. (locality 11, fig. 3) from early oxfordian to early kimmeridgian and from late kimmeridgian to the middle tithonian (tišljar et al., 1989; tišljar & velić, 1991), and on the dinara mt. (locality 10a) from late tithonian to the early valanginian (fig. 5). in western bosnia emersion of similar duration to that in istria was recorded nw of drvar (locality 14 – šušnjar & bukovac, 1978), in srnetica mt. se from bosanski petrovac (locality 15 – vrhovčić et al., 1983) and nw from glamoč (locality 16 – ahac et al., 1977), in eastern herzegovina n and nw from trebinje (locality 17 – natević & petrović, 1967), and in montenegro in the region of nikšić (locality 7 – radoičić & vujisić, 1970; vujisić, 1972) and nw of cetinje (locality 9 – antonijević et al., 1969). 2.2. megafacies of lagoonal and subtidal inner platform oncoid, pelletal and skeletal mudstones/wackestones (j–2) megafacies j–2 is a dominant facies type within jurassic deposits (figs. 2–4). it is composed of thick-bedded to massive wackestones/packstones to floatstones with algal oncoids (“cyanoids”– riding, 1983), as well as pelletal and skeletal wackestones and mudstones containing faecal pellets, gastropod cortoids and centripetally micritized benthic foraminiferal tests and mollusc bioclasts. massive and/or thick-bedded mudstones and wackestones of megafacies j–2 are predominant in the middle lias, lower and middle dogger, oxfordian and kimmeridgian carbonates. this megafacies prevails in velika kapela mt. and in the senj–ogulin profile (locality fig. 2 correlation of jurassic and cretaceous platform carbonate megafacies from the senj–ogulin profile (modified after matičec et al., 1997), triassic, jurassic, cretaceous and palaeogene carbonates of northern margin of the carbonate platform in the karlovac–duga resa area (modified after bukovac et al., 1974; dragičević & velić, 1994, 2002), and cretaceous–palaeogene carbonates of northern margin of the carbonate platform in the donji bešpelj area, bosnia and herzegovina (modified after dragičević, 1987; dragičević & velić, 1994). legend: k–10: megafacies of calclithite–marly flysch; k–9a: megafacies of slope carbonates: carbonate debrites and coarse-grained carbonate turbidites; k–9b: megafacies of slope carbonates: middleto fine grained carbonate turbidites or allodapic limestones; k–6: megafacies of rudist coquinas/coquinites with small rudist biostromes and lithosomes; k–6a: megafacies of coarse-grained rudist coquinas/coquinites accumulated within shallows with agitated water, “intra-shelf troughs”, and particularly on the slope toward the open sea; k–5: megafacies of intraclastic/peloidal and skeletal foreshore and shoreface grainstones and packstones; k–4: megafacies of inner platform lagoonal and shallow subtidal oncoid and peloidal micritic limestones; k–3: megafacies of peritidal–tidal flat pelletal and stromatolitic limestones forming shallowing-upward cycles; k–2: megafacies of peritidal and vadose limestones, black-pebble breccia/conglomerates, emersion breccia, clays, swamp deposits and palaeosols, long-lasting emersions and bauxites; j–9: megafacies of late-diagenetic dolomites; j–8: megafacies of “limestones with cherts” (including “lemeš deposits”), deposited within intraplatform troughs with temporary or continuous connection to the open sea; j–7: megafacies of peri-reefal bioclastic limestones (rudstones and grainstones) with hydrozoan, stromatoporoid and coral patch reefs and biostromes; j–6: megafacies of skeletal and intraclastic grainstone/rudstones deposited in shallows with agitated water; j–5: megafacies of ooid grainstones deposited in environments with agitated water and ooid bars; j–4: megafacies of lithiotid and brachiopod lithosomes and tempestite coquinas of shallow subtidal and lagoonal regions of the inner platform; j–3: megafacies of bioturbated and late-diagenetically dolomitized “spotty limestones” – mudstones and wackestones deposited in isolated and restricted lagoon/deeper subtidal areas of the inner platform; j–2: megafacies of lagoonal and subtidal inner platform oncoid, pelletal and skeletal mudstones/wackestones; j–1: megafacies of peritidal micritic, fenestral and vadose limestones with interbeds of early-diagenetic dolomites and emersion breccia, emersions and occasional bauxites; t–3: megafacies of peritidal and supratidal carbonates – main dolomite (hauptdolomit). 144 g eologia c roatica 55/2 145 tišljar, v lahović, velić & s okač: c arbonate p latform m egafacies of the jurassic and c retaceous d eposits... 6b–c on fig. 1), in the d ogger of velebit m t. (localities 3a–b), and b iokovo m t. (locality 11), as w ell as in the trnovski g ozd (locality 5f) and k arlovac area (locality 6a), and low er m alm of the d ubrovnik region (locality 18b – o sojnik–g repci area). sim ilar deposits are also know n w ithin jurassic deposits of other areas of the k arst d inarides, but lite rature data are quite scarce. e.g., deposits belonging to m egafacies j–2 can also be found in the d ogger of the central part of the k arst d inarides in w estern b osnia 3a south.velebit mt. upper n '//////) ?'..?'".az..-... n 11 biokovomt. :e .......... _ ............. -....., ...j ,,_ r. ....... <fr" :l ,~{0rrf:i:t 1",~'::;":,\~;$'''';;;,.,>,.~~ -.....,~-'~n ..... ~ o kim""",,,,,,,g zw <~ i ~;'//-%:q ~ a: " wq "" o ~ upper '\";';";"';";';'~~~::?-~--'~ r ... ~ ~;;;~ .... ,~ .. -.... -. : .... :: ... : .... ~:.!: ... ~z£l£lc..-.. ulz~ --'azr-£.t't~ .-." ', .. " '~' ;,,',;:., ~ .... : mmmmr;:!:'*'~:";';~;:·"~';~ i ::... ~~ upper triassic t-3 main dolomite -j-1 j-2 .. megafacies units ~~ ~':\:i;':~': j·3 j-4 j-5 j-6 18a sland zavala jrofile :" '.,~ :, . " ~:,,,, , -c;.""~'."" " ' ;;, .~."". j-7 18b osojnik·grepci , ...... . ~ .•. j-9 k-2 k-3 18e kqnavoska brda l. ~/////) .////// . "~, ,-, "~, ,-, ,-, upper triassic 144 geologia croatica 55/2 145tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... and croatia, in malm deposits of suha krajina in slovenia (locality 5a; dozet, 1995), the oxfordian and kimmeridgian of se montenegro, and upper kimmeridgian and tithonian of eastern herzegovina (radoičić, 1966), etc. upper malm deposits are frequently composed of algal wackestones, (so-called clypeina limestones), which usually represent the initial members of smallscale shallowing-upward cycles (tišljar & velić, 1991). 2.3. megafacies of bioturbated and latediagenetically dolomitized “spotty limestones” – mudstones and wackestones deposited in isolated and restricted lagoon/deeper subtidal areas of the inner platform (j–3) deposits of megafacies j–3 are typical for the upper lias of the velebit mt. (figs. 2 and 3; localities 3a – mali halan and 3b – kubus), velika kapela mt. and senj–ogulin profile (locality 6b–c), and platak–gornje jelenje in gorski kotar (locality 6d). this megafacies is widely distributed in the western part of the karst dinarides, stretching from w bosnia and s croatia (northern dalmatia) towards the nw into southern slovenia (tišljar & velić, 1991; dozet & šribar, 1998a; dragičević & velić, 2002). however, it is completely missing in the ese, from central bosnia towards herzegovina, montenegro and the croatian southern adriatic coast (fig. 3). the main characteristic of these “spotty limestones” is intense bioturbation of carbonate muds in restricted areas with very reduced fossil assemblages, indicating low sedimentation rates during late lias. the depositional area was probably an isolated, restricted lagoon in the inner part of the platform, formed by the interaction of gentle synsedimentary tectonics and eustatic sealevel change. this spotty appearance is a consequence of bioturbation and different amounts of organic matter in a host rock (predominantly mudstones) and bioturbation infillings (mostly wackestones to packstones), although differences have been subsequently exaggerated by the variable influences of late-diagenetic dolomitization and recrystallization. 2.4. megafacies of lithiotid and brachiopod lithosomes and tempestite coquinas of shallow subtidal and lagoonal regions of the inner platform (j–4) deposits separated into megafacies j–4 are present only within the middle lias deposits (figs. 2 & 3), in velebit mt. (localities 3a–b), near duga resa in the karlovac area (locality 6a), velika kapela mt. and senj–ogulin profile (locality 6b–c), and dubrovnik area (locality 18c – konavoska brda). biostromes are 0.3–0.8 m thick, and are characterised by their limited lateral extent. they are composed of very large shells of lithiotids and brachiopods lithified in living position, and occur only at some localities, for example, on the kubus ridge of velebit mt. (locality 3b) and konavoska brda near dubrovnik (locality 18c). however, shell coquinas and tempestite coquinas consisting of coarse debris of lithiotids and brachiopods very often occur in penecontemporaneous deposits, both in these and other aforementioned localities (e.g. jelaska & velić, 1971; tišljar & velić, 1991; buser & debeljak, 1996; debeljak & buser, 1998). limestones with lithiotids can be found throughout the area of the former platform except for its marginal parts (fig. 1; dragičević & velić, 2002). depending on bathymetry and morphology of the sea bottom, the frequency of these beds varies from place to place, with maximal 4 to 12 beds in middle lias of the velebit mt. (locality 3b; sokač, 1973), and minimal 1 to 3 beds in the w gorski kotar (platak–gornje jelenje – locality 6d). tempestite coquinas were deposited by storm waves and storm tides in shallow subtidal to lower intertidal environments, and are associated with limestones of megafacies j–1, j–2 and j–6. 2.5. megafacies of ooid grainstones deposited in environments with agitated water and ooid bars (j–5) deposits of megafacies j–5 are most common in the middle and upper lias and dogger of the trnovski gozd (locality 5f on fig. 1), in the upper lias, dogger and malm succession of velika kapela mt. and the senj–ogulin profile and karlovac area (fig. 2), and fig. 3 correlation of the jurassic platform carbonate megafacies units of velebit mt. (mali halan), biokovo mt. (area of kozica) and the southern adriatic (locations 18a – osojnik and 18b – konavoska brda). partly modified after tišljar & velić (1991). legend: k–3: megafacies of peritidal–tidal flat pelletal and stromatolitic limestones forming shallowing-upward cycles; k–2: megafacies of peritidal and vadose limestones, black-pebble breccia/conglomerates, emersion breccia, clays, swamp deposits and palaeosols, long-lasting emersions and bauxites; j–9: megafacies of late-diagenetic dolomites; j–7: megafacies of peri-reefal bioclastic limestones (rudstones and grainstones) with hydrozoan, stromatoporoid and coral patch reefs and biostromes; j–6: megafacies of skeletal and intraclastic grainstone/rudstones deposited in shallows with agitated water; j–5: megafacies of ooid grainstones deposited in environments with agitated water and ooid bars; j–4: megafacies of lithiotid and brachiopod lithosomes and tempestite coquinas of shallow subtidal and lagoonal regions of the inner platform; j–3: megafacies of bioturbated and late-diagenetically dolomitized “spotty limestones” – mudstones and wackestones deposited in isolated and restricted lagoon/deeper subtidal areas of the inner platform; j–2: megafacies of lagoonal and subtidal inner platform oncoid, pelletal and skeletal mudstones/wackestones; j–1: megafacies of peritidal micritic, fenestral and vadose limestones with interbeds of early-diagenetic dolomites and emersion breccia, emersions and occasional bauxites; t–3: megafacies of peritidal and supratidal carbonates – main dolomite (hauptdolomit). 146 geologia croatica 55/2 147tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... in the lower, middle and upper dogger and lower malm of velebit mt., upper lias/lower and middle/ upper dogger of biokovo mt. and upper lias and lower to middle dogger in the dubrovnik area (fig. 3; dragičević & velić, 2002). ooid grainstones and bioclastic–ooid grainstones are also common in oxfordian strata of western istria and western gorski kotar area (fig. 4). deposits of this megafacies are also widely distributed in several levels of jurassic rocks in other parts of the karst dinarides, most commonly in upper lias–lower dogger, dogger and malm in general, and oxfordian and tithonian. the best outcrops are described from bosnia and herzegovina, se of kupres (locality 20), montenegro (see dragičević & velić, 2002 – this vol.; farinacci & radoičić, 1964; radoičić, 1966; d’argenio et al., 1971), and especially slovenia (buser, 1978, 1979; orehek & ogorelec, 1979, 1981; ogorelec & dozet, 2000), in different levels of stratigraphic range middle lias to kimmeridgian (dozet & šribar, 1998a), and in some places throughout the dogger, oxfordian and lower kimmeridgian (strohmenger & dozet, 1990; dozet, 2000). ooid grainstones were frequently deposited in the form of ooid bars, exhibiting large-scale cross-bedding, but also ooid grainstones or ooid–bioclastic–intraclastic grainstones to rudstones are common as the first member of the shallowing-upward cycles. in this type of parasequences the second member is pelletal or oncoid wackestone or peloid–oncoid floatstone, while the third, upper member of the cycles, is pelletal or oncoid wackestone with fenestral fabric, locally with vadose features (tišljar & velić, 1991). ooid grainstones are composed of well-sorted, spheroidal and frequently broken ooids and mosaic and/ or fibrous calcite cement. rocks comprise different ooid types: most common are radial, tangential and micritic, although there are also oomoldic, leached and broken and regenerated ooids. oomoldic and leached ooids are more frequent only within oolitic grainstones of lower dogger age in the dubrovnik area (locality 18b – osojnik–grepci profile) and from the lower lias on velebit mt. (locality 3a – mali halan). their abundance indicates that ooid tidal bars were occasionally exposed to the influence of fresh water, causing complete or partial leaching of their probably originally aragonitic cortex. ooid grainstones of megafacies j–5 were deposited in environments of ooid shoals and bars with high water-energy. 2.6. megafacies of skeletal and intraclastic grainstone/rudstones deposited in shallows with agitated water (j–6) megafacies j–6 consists of bioclastic grainstones and rudstones, and sporadically of floatstones containing well-sorted and rounded intraclasts, bioclasts and coated bioclasts (“cortoids”), 0.5–10 mm in size. bioclasts of hydrozoans and other stromatoporoids, intraclasts and ooids are predominant, while fragments of corals and gastropods are relatively rare. these rocks are characterised by their high content of drusy mosaic and often fibrous rim calcite cement, and they originated by the destruction of skeletons of reef and patch-reef organisms in open shoals with high water energy and normal marine salinity and by migration and deposition of bioclasts in shoals with agitated water. deposits of megafacies j–6 (fig. 4) are common only in the malm of western and southern slovenia in the trnovski gozd area (locality 5f – turnšek et al., 1981; ogorelec et al., 1996), and in croatia in the pokuplje (locality 21) and karlovac area (locality 6a), in western istria (locality 1a – “tidal bar facies” in tišljar & velić, 1987), in oxfordian sediments of western gorski kotar area (locality 6d – platak–gornje jelenje), in the upper tithonian of velika kapela mt. and senj–ogulin profile (locality 6b–c), and in the oxfordian of velebit mt. (mali halan – locality 3a) and biokovo mt. (locality 11). a variety of megafacies j–6 deposits, composed of well-sorted and rounded intraclasts and bioclasts of pachyodont shells and echinoderms deposited in shallows with agitated water, occur in the lower and middle lias in western slovenia, in the middle lias and upper dogger of velebit mt. (mali halan – locality 3a), while in the lower dogger of the biokovo mt. (locality 11) skeletal and intraclastic grainstones/rudstones occur (fig. 3). deposits of this variety of megafacies j–6 are especially important for the middle dogger succession of the dubrovnik area (localities 18a–c on fig. 3). 2.7. megafacies of peri-reefal bioclastic limestones (rudstones and grainstones) with hydrozoan, stromatoporoid and coral patch reefs and biostromes (j–7) deposits of megafacies j–7 only occur sporadically in typical carbonate platform deposits, usually within the succession of megafacies j–6 in malm deposits (figs. 2 & 3). smaller coral and/or hydrozoan patch-reefs were well developed in the oxfordian of the island of lastovo (locality 19), in the tithonian of velika kapela mt. and the senj–ogulin profile (locality 6b–c) and in the gorski kotar (zlobin area – locality 6f). during the late jurassic the northern, ne and se margins of the platform were characterised by an almost continuous belt of coral–hydrozoan barrier reefs stretching from w slovenia (turnšek, 1966; turnšek et al., 1981) to se montenegro and nw albania (velić et al., 2002a). in addition, there were also coral–hydrozoan reefs within the platform interior, where they surrounded intraplatform depressions, e.g. in gorski kotar (velić et al., 1994, 2002b) or the “lemeš” trough extending approximately from the vicinity of bihać in w bosnia (locality 22) towards 146 geologia croatica 55/2 147tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... the south to central dalmatia, i.e. knin, drniš and sinj (velić et al., 2002a). besides this, barrier reefs, extending for tens or hundreds of kilometres, there were also isolated patch reefs, for example near senj (locality 6b), in gorski kotar near zlobin (locality 6f), in biokovo (locality 11) in croatia, as well as in the area of nanos, hrušica (localities 5c–d) and dolenjska (locality 5b) in slovenia (turnšek, 1997). most of these reefs were not preserved in situ as skeletal reefs – they occur as smaller or larger quantities of skeletal detritus in the form of peri-reefal bioclastic limestones of a rudstone/grainstone type. large organic reefs or reef complexes have not been recognized within jurassic carbonates in the croatian part of the adriatic carbonate platform. some of these ancient reefs have been completely destroyed and redeposited (tišljar & velić, 1991), e.g. there are relics of destroyed reefs in the upper malm of the pokuplje and karlovac area (localities 21 and 6a), in gorski kotar near zlobin (locality 6f), in the oxfordian of western istria (locality 1a), in the lower tithonian of velika kapela mt. (locality 6b) and in the upper malm of biokovo mt. (locality 11). opinion is divided concerning the stratigraphic position of reefal/peri-reefal deposits within upper jurassic deposits in slovenia. for example: turnšek et al. (1981), buser (1989) and turnšek (1997) consider these deposits to be of oxfordian–kimmeridgian age, while nikler (1978) considered that they are of upper kimmeridgian–tithonian age, similar to the age of corresponding deposits in croatia (milan, 1965, 1969; nikler, 1965, 1969, 1978; bukovac et al., 1974, 1984; velić, 1977; tišljar & velić, 1991; velić et al., 1994). reefal/peri-reefal deposits with abundant corals and hydrozoans are very common along the ne margin of the platform in the area from central bosnia to southern montenegro, but their stratigraphic age is generally determined as upper jurassic (e.g. papeš, 1972, 1985; vujnović, 1980; mirković & vujisić, 1989; mirković et al., 1977, 1979). 2.8. megafacies of “limestones with cherts” (including “lemeš deposits”), deposited within intraplatform troughs with temporary or continuous connection to the open sea (j–8) megafacies j–8 comprises “limestones with cherts”, and it is especially well developed in the kimmeridgian of velika kapela mt., in the area of karlovac (fig. 2) and within the so-called “lemeš beds” which can be found in the central part of the platform from bihać in nw bosnia, along the una valley, through e lika (donji lapac, udbina) and n dalmatia (knin, drniš) to central dalmatia (sinj) (fig. 7 in velić et al., 2002a). comparable deposits are completely missing in the coastal area and on the islands of the central and southern adriatic (tišljar & velić, 1991). “limestones with cherts” deposited within an intraplatform trough in the area of the present day velika kapela mt. (locality 6b–c) had only weak, temporary connections with the open sea. on the contrary, for deposits of the so-called “lemeš beds” a continuous and direct connection with the open tethys is supposed. “limestones with cherts” have also been found in slovenia, where according to buser (1989) in the region of trnovski gozd (locality 5f) they were accumulated somewhat earlier, during the oxfordian, in a deeper trench formed within the platform, which was connected towards the north with the slovenian basin. in the area of velika kapela mt. and the senj–ogulin profile (locality 6b–c, fig. 2) thinto well-bedded grey to dark grey mudstones/wackestones with interbeds of cherts gradually overlaid oxfordian deposits of megafacies j–2. their thickness is very variable, and their upper boundary is also gradual with redeposited bioclastic limestones of megafacies j–5 (fig. 2). in their lower part “limestones with cherts” are composed of grey to dark grey pelletal–bioclastic wackestones and mudstones with nodules and rare lenses of cherts. in their upper part within the well-bedded rocks of similar lithology, but including small peloids, oncoids, pelagic crinoids, bioclasts of echinoderms, corals, hydrozoans and stromatoporoids, rare ooids and very rare ammonites, there are lot of nodules, lenses and intercalations of cherts. cherts comprise numerous relics of radiolarians and spicules of silica sponges. they originated by earlydiagenetic silicification of carbonate muds under the influence of solutions enriched in silicic acid originating from fine volcanoclastic detritus, and some beds are direct products of the alteration of tuffs, as first mentioned by šćavničar & nikler (1976). “lemeš beds” were described as platy to thickbedded limestones with interbeds and lenses of cherts and/or thin-bedded silicified limestones (ivanović et al., 1977, 1978; krkalo et al., 1995). limestones are mostly pale brown fossiliferous mudstones to wackestones, but also wackestones to packstones comprising pellets, ooids, oncoids and bioclasts. they contain relatively numerous ammonites, aptichuses, fish remains, brachiopods, benthic and pelagic foraminifera, calcisphaeres and radiolarians. according to krkalo et al. (1995) “lemeš beds” at a typical locality in svilaja mt. (lemeš, maovice – locality 23) within the continuous succession of upper jurassic deposits overlie dark grey oxfordian limestones (probably representing deposits of megafacies j–2). in their basal part there is an alternation of platy and thin-bedded limestones (beds up to 20 cm thick) with chert lenses and nodules (cmto dm-thick). limestones predominate, but the proportion of cherts increases upwards. interbeds and lenses of montmorillonitic clays containing volcanic glass and pyroclastic quartz have been determined. in the central part of the succession thin bedded siliceous sediments prevail – silicified carbonates (predominantly mudstones) and 5–10 cm thick cherts with relics of ammonites and bivalves, characterised by occurrences 148 geologia croatica 55/2 149tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... 1a w&s istria ~ i ii: w 0w i 2b l offshore ~ well im-1 i ., ~ ::> 0 w ~ i-' w '" 0 i '" ~ w .. f ~ .. ::> ~ i ~ 0 ., ::> 0 w i 0 ~ " w l '" 0 ~ .<g 110 .,w !~ ",0 w'" .. w !l;~ ~ 0-5 emllfllion ~ 200m 150m 100m 50m om callovian w z l:ll ~ p-3 o~ ~ @ ____ • p-2 1£ _ kp-1 k-9b k-9a k-8 k-7 k-6 k-5 k-4 j-9 u j-6 ~ ~ [,',:,:: t: :,j j-5 ~i==l l===:::j j-2 = j-1 6d gorski kotar: (platak gomje jelenje) 148 geologia croatica 55/2 149tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... of horizontal and oblique lamination. the upper part of the “lemeš beds” succession begins with the alternation of limestones and cherts, characterised by the gradual reduction in the proportion of chert (they finally disappear completely) and thickening of limestone beds (up to 80 cm), containing successively more shallow water carbonate debris, especially bioclasts of bivalves and echinoderms. for more details on the kimmeridgian environments and deposits in the area of velika kapela see velić et al. (1994, 2002b – this vol.) and bucković (1995). 2.9. megafacies of late-diagenetic dolomites (j–9) megafacies j–9 includes large masses, bodies and layers of microcrystalline to coarsely-crystalline dolomites with mosaic texture. they often contain relics of more or less intensively dolomitized limestones, mainly of megafacies j–2, j–6 and j–7, and rarely of megafacies j–1 (figs. 2–4). their late-diagenetic origin is suggested by the following features: the relative large size of dolomite crystals (0.02–0.8 mm), selective dolomitization of limestone components, occurrence of irregular dolomite lenses and bodies within undolomitized or weakly dolomitized limestones, gradual transitions of limestones to dolomite and undolomitized relics of limestones in dolomites, practically constant structures and composition of dolomites in large areas formed by dolomitization of different structural, genetic and stratigraphic types of limestones, as well as their high ca–excess (these are usually ca52–57 mg43–48 dolomites). megafacies j–9 is the dominant megafacies unit of the lower oxfordian and upper tithonian of velika kapela mt. and the senj–ogulin profile (locality 6b–c), the lower and middle lias in karlovac area (locality 6a), upper malm of the central and southern adriatic coast – biokovo mt. and dubrovnik area (localities 11 and 18a–c), and the upper malm in the offshore well im–1 (locality 2b). it is also very common in the lower lias and lower dogger of the gorski kotar area (locality 6d – platak–gornje jelenje), velika kapela mt. and the senj–ogulin profile (localities 6b–c), velebit mt. (localities 3a–b), biokovo mt. (locality 11) and in the southern adriatic region (island of lastovo – locality 19, dubrovnik area – localities 18a–c). in central croatia, from the vicinity of vrbovsko, ogulin, plaški and lička jesenica to the wider region of the plitvička jezera lakes (the area between localities 6c and 4 and s of locality 4), a belt from a few hundred m to more than 10 km wide, composed of late-diagenetic dolomites of upper malm to neocomian age crops out. within this belt in the area between josipdol, modruš and plaški an almost complete jurassic succession (from the middle lias to the end of the malm) is completely dolomitized. the age has been determined since within these dolomites lenses and interbeds of undolomitized limestones comprising index fossils are more or less common. in the liassic part of this succession there are indications for occurrences of early-diagenetic dolomites. 3. carbonate, clay-bearing and sabkha anhydrite megafacies of the lower cretaceous and carbonate megafacies of the upper cretaceous deposits cretaceous carbonate deposits of the karst dinarides can be divided into 10 megafacies units: k–1: megafacies of supratidal early-diagenetic dolomites, which can be subdivided into 3 different sub lithofacies types: k–1a: facies of supratidal early-diagenetic dolomites without evaporites, k–1b: facies of supratidal early-diagenetic dolomites with evaporites, i.e. sabkha cycles, and k–1c: facies of supratidal laminated early-diagenetic dolomites with crystal moulds of evaporite minerals; k–2: megafacies of peritidal and vadose limestones, black-pebble breccia/conglomerates, emersion breccia, clays, swamp deposits and palaeosols, long-lasting emersions and bauxites; fig. 4 megafacies units of the malm, cretaceous and palaeogene deposits: correlation of the off-shore well im–1 (northern adriatic sea, deep marine succession – partly modified after veseli, 1999) with megafacies of western and southern istria and western gorski kotar (platak area) (partly modified after tišljar et al., 1994, 1998). legend: p–3: megafacies of foraminiferal limestones; p–2: megafacies of peritidal/lagoonal stromatolitic, pelletal and skeletal micritic limestones; kp–1: megafacies of emersions with bauxites, and terrestrial, fresh-water and brackish (liburnian) deposits; k–9a: carbonate debrites and coarse-grained carbonate turbidites; k–9b: middleto fine grained carbonate turbidites or allodapic limestones; k–8: megafacies of late-diagenetic dolomites; k–7: megafacies of limestones with pelagic fauna which originated during phases of temporary platform drowning; k–6: megafacies of rudist coquinas/coquinites with small rudist biostromes and lithosomes; k–5: megafacies of intraclastic/peloidal and skeletal foreshore and shoreface grainstones and packstones; k–4: megafacies of inner platform lagoonal and shallow subtidal oncoid and peloidal micritic limestones; k–3: megafacies of peritidal – tidal flat pelletal and stromatolitic limestones forming shallowing-upward cycles; k–2: megafacies of peritidal and vadose limestones, black-pebble breccia/conglomerates, emersion breccia, clays, swamp deposits and palaeosols, long-lasting emersions and bauxites; k–1: megafacies of supratidal early-diagenetic dolomites; j–9: megafacies of late-diagenetic dolomites; j–6: megafacies of skeletal and intraclastic grainstone/rudstones deposited in shallows with agitated water; j–5: megafacies of ooid grainstones deposited in environments with agitated water and ooid bars; j–2: megafacies of lagoonal and subtidal inner platform oncoid, pelletal and skeletal mudstones/wackestones; j–1: megafacies of peritidal micritic, fenestral and vadose limestones with interbeds of early-diagenetic dolomites and emersion breccia, emersions and occasional bauxites. 150 geologia croatica 55/2 151tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... k–3: megafacies of peritidal–tidal flat pelletal and stromatolitic limestones forming shallowing-upward cycles; k–4: megafacies of inner platform lagoonal and shallow subtidal oncoid and peloidal micritic limestones; k–5: megafacies of intraclastic/peloidal and skeletal foreshore and shoreface grainstones and packstones; k–6: megafacies of rudist coquinas/coquinites with small rudist biostromes and lithosomes; k–7: megafacies of limestones with pelagic fauna which originated during phases of temporary platform drowning; k–8: megafacies of late-diagenetic dolomites; k–9: megafacies of slope carbonates: debrites and turbidites, and k–10: megafacies of calclithite–marly flysch. 3.1. megafacies of supratidal early-diagenetic dolomites deposits of megafacies k–1 occur within cretaceous platform carbonates of the dinaric karst region as three types, differing according to their origin and depositional environments. 3.1.1. facies of supratidal early-diagenetic dolomites without evaporites (k–1a) deposits of facies k–1a only occur in lower cretaceous carbonates in the berriasian succession of western istria (locality 1a), berriasian and valanginian carbonates of southern slovenia (orehek & ogorelec, 1979, 1981; dozet, 1992a, b; dozet & šribar, 1998b), upper albian/vraconian of biokovo mt. (locality 11), offshore well kate–1 in the kornati area (locality 2f) and in the dubrovnik area (locality 18d). 3.1.2. facies of supratidal early-diagenetic dolomites with evaporites, i.e. sabkha cycles (k–1b) deposits of facies k–1b only occur in the lower cretaceous deposits in wells drilled in the ravni kotari area (locality 25a: wells rk–1, rk–3, rk–4, locality 25b: nin–1) and wells in the adriatic region: ol–1 (locality 26a – island of olib), and do–1 (locality 27 – island of dugi otok). lower cretaceous sabkha anhydrites are represented by typical sabkha cycles (tišljar, 19843, 2001), composed of member a (kerogenous ostracod wackestones/mudstones deposited in subtidal–lagoon), member b (homogenous and stromatolitic intertidal/ supratidal early-diagenetic dolomite) and member c (nodular sabkha anhydrite). cretaceous sabkha anhydrites from deep wells have significantly different mineralogical, petrological, sedimentological and geochemical properties from upper permian anhydrites (papeš, 1985; šušnjara et al., 1992; tišljar, 1992) or “permo–triassic(?)” evaporites of central and northern dalmatia and una valley in lika and bosnia (sakač et al., 1970; herak, 1973, 1983; ivanović et al., 1977; papeš et al., 1982; bahun, 1985). 3.1.3. facies of supratidal laminated early-diagenetic dolomites with crystal moulds of evaporite minerals (k–1c) deposits of facies k–1c only crop out within upper santonian–lower campanian peritidal deposits in the area of sućuraj on the island of hvar (locality 28 on fig. 1). this megafacies is characterised by the typical alternation of thin (0.2–6 mm), very wavy laminae of light and dark coloured dolomites (therefore it is called “zebra dolomite”), as well as fenestral fabric and desiccation cracks, resulting from recurrent dehydration and moisturisation by high and storm tides in supratidal environments. occurrence of this type of deposits within upper santonian–lower campanian peritidal carbonates of megafacies k–3 has very important sedimentological, palaeomorphological and palaeoclimatological significance for the interpretation of sedimentary environments and evolution of the adriatic carbonate platform in the late cretaceous. 3.2. megafacies of peritidal and vadose limestones, black-pebble breccia/ conglomerates, emersion breccia, clays, swamp deposits and palaeosols, long-lasting emersions and bauxites (k–2) deposits of megafacies k–2 without long-lasting emersion and bauxites are most common within limestones of the upper aptian, and in some parts of hauterivian, barremian, and lower albian successions in the continental part of the karst dinarides (figs. 4 and 5). they also occur on the islands of brijuni, cres, lošinj, vis, hvar, korčula, mljet and the pelješac peninsula (localities 1e, 29, 31a, 33, 28, 34, 35 and 36), as well as in onshore and offshore wells pula–1, susak–1, premuda–1, kate–1 and boraja–1, i.e. on localities 1d, 2d–f and 12 (tišljar, 1978a, b, 1980, 1986; tišljar et al., 1981, 1997; velić & tišljar, 1987; velić et al., 1989, 1995; tišljar & velić, 1991; veseli et al., 1991; fuček et al., 1995; veseli, 1994; vlahović et al., 2000; husinec et al., 2000). after important relative sea level falls connected with emersions, e.g. after the regional aptian emersion, several shallowing-upward cycles were initiated 3 tišljar, j. (1984): sedimentološka i litofacijesna interpretacija karbonatno–anhidritnog kompleksa dubokih bušotina ravni kotari–3, dugi otok–1, nin–1, brač–1 i lastovo–1 [sedimentological and lithofacies interpretation of the wells rk–1, do–1, nin–1, brač–1 and lastovo–1 – in croatian].– unpubl. study, ina–naftaplin, zagreb, 64 p. 150 g eologia c roatica 55/2 151 tišljar, v lahović, velić & s okač: c arbonate p latform m egafacies of the jurassic and c retaceous d eposits... fig. 5 c orrelation of the low er c retaceous platform carbonate m egafacies units of d inara m t., b iokovo m t., d ubrovnik area and the island of k orčula. p artly m odified after tiš lja r et al. (1983b) and tiš lja r & v e lić (1991). legend: k –8: m egafacies of late-diagenetic dolom ites; k –7: m egafacies of lim estones w ith pelagic fauna w hich originated during phases of tem porary platform drow ning; k –6: m egafacies of rudist coquinas/coquinites w ith sm all rudist biostrom es and lithosom es; k –5: m egafacies of intraclastic/peloidal and skeletal foreshore and shoreface grainstones and packstones; k –4: m egafacies of inner platform lagoonal and shallow subtidal oncoid and peloidal m icritic lim estones; k –3: m egafacies of peritidal–tidal flat pelletal and strom atolitic lim estones form ing shallow ingupw ard cycles; k –2: m egafacies of peritidal and vadose lim estones, black-pebble breccia/conglom erates, em ersion breccia, clays, sw am p deposits and palaeosols, long-lasting em ersions and bauxites; k –1: m egafacies of supratidal early-diagenetic dolom ites; j–9: m egafacies of late-diagenetic dolom ites; j–6: m egafacies of skeletal and intraclastic grainstone/rudstones deposited in shallow s w ith agitated w ater; j–2: m egafacies of lagoonal and subtidal inner platform oncoid, pelletal and skeletal m udstones/w ackestones; j–1: m egafacies of peritidal m icritic, fenestral and vadose lim estones w ith interbeds of early-diagenetic dolom ites and em ersion breccia, em ersions and occasional bauxites. turonian 10a dinara mt. 11 biokovo mt. _ <d _0 _ <d -i k-4 cenomanian i ~"'(1 -tfi, )k. vraconian ~ ~ ~ ~ i o 0 • k .. k-5 k-4 k-5 z ,g; ..... '" -' '" k-3 k-4 k-5 i ~;; :~~ ~ k-4 iiddi::cow ., ...... ~ i!1;: ~0 0~ i ~~<~~~;;i ~ hauterivian )=:: ~ ;-;;: k-3 ,~ ~<d , ~ ~ ~0 ~ ~0 ~ ~ k .. --~---, .-~ ~ _ <d _ _ ~ 0 ~ o ~ valanginian l~~ k-3 ... "'" r. j.6 tithonian f·'···· ···,··· .• ,,'.1 j-1 34 islandof korgula _0 _ <d _ <d i ~ i ~< ~< '(213 ,~ ~<d ,~ ~<d , k-4 o _ 0_ ~. -~---' ... --, cenomanian vraconian 18d dubrovnik (cerovac hum) k .. ~~ .~ k~""";" ----~~~ii~~~~k~-3~ .. ~--upper albian hauterivian ~ valanginian tithonian .~ m ~0 ~ <d ... _ i k-4 ~k-5 k-4 megafacies units k-8 ~k-7 r,,:·:vj k-6 -, .. :.,., k-5 i~~~ ;; 1 k-4 k-3 t:----='l k-2 ~. k-1 / . . //j /. , j-9 j-6 i i j-2 i!!!!!!i j-1 300m 200m 100m om 152 geologia croatica 55/2 153tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... composed of peritidal limestones alternating in vertical, partially even in lateral succession with soft pebble conglomerates, black-pebble breccias, emersion breccias, grey and dark clay intercalations and palaeosols. this was a consequence of oscillatory relative sea level fluctuations caused by the interaction of eustatic changes, tidal flat and shoreline progradation and gentle synsedimentary tectonics (tišljar et al., 1995, 1998; matičec et al., 1996). the frequent short-lived emersions in lower cretaceous limestones were connected with interruptions of sedimentation, temporary emersions of incompletely consolidated carbonate deposits and the appearance of thin intercalations of soft pebble conglomerates, blackpebble breccias, emersion breccias, grey and dark green clay intercalations and palaeosols. the black-pebble conglomerates and breccias consist of poorly sorted angular to more or less rounded fragments or pebbles of stromatolites, pelletal and fenestral wackestones to packstones and mudstones originating from underlying or lateral beds, in a clayey and/or marly matrix. usually they occur as channel or depression fills on eroded (or in the case of longer hiatuses even karstified) surfaces of peritidal limestones. black-pebbles are frequently 10 to 50 mm in diameter, which were originally intertidal or subtidal limestone clasts blackened by organic matter and pyrite in coastal swamps, bogs or pools (tišljar, 1986). the grey, greenish and dark clays were deposited during relative sea level fall when swamp environments were developed in the coastal area (tišljar, 1986; tišljar et al., 1997). greenish clays associated with lower cretaceous peritidal and lagoonal carbonates, especially within the late aptian to middle albian long-lasting emersion in istria (velić et al., 1989), but also in other parts of the platform (e.g., slovenia – jurkovšek et al., 1996), show evidence of subaerial exposure and pedogenesis, and are considered palaeosols. the very high smectite content in these deposits indicate an additional volcanic contribution before and during the subaerial exposure (ottner et al., 1999; durn et al., 2000). vast tidal flats interfingering with shallow subtidal areas and coastal swamps in the area of present day istria represented during the cretaceous, suitable settings for dinosaurs, traces of which have been documented in deposits of megafacies k–2 and k–3 within the hauterivian (including bones preserved in swamp environments – dalla vecchia, 1998; dini et al., 1998; dalla vecchia et al., 2000a), barremian, albian and upper cenomanian (bachofen-echt, 1925; polšak, 1965b; tišljar et al., 1983a; velić & tišljar, 1987; dalla vecchia et al., 1993, 2000b, 2002; dalla vecchia & tarlao, 1995). in neighbouring slovenia there are even younger occurrences of dinosaurs of upper campanian to lower maastrichtian age (debeljak et al., 1999, 2002). such an important time span with appropriate conditions for dinosaur survival represents a very important fact for the interpretation of palaeogeomorphological and sedimentological relationships in the nw part of the adriatic carbonate platform (dalla vecchia & tarlao, 1995; matičec et al., 1996). in the karst dinarides area, long-lasting emersions with bauxites have also been documented within cretaceous deposits. there are several stratigraphic levels characterised by emersions and significant karstification. the oldest level is represented by the previously mentioned emersion at the jurassic–cretaceous boundary (kupres area – locality 20, fig. 5), where tithonian limestones represent the footwall and valanginian limestones the hanging wall of the bauxites. in the area of grmeč mt. in w bosnia (e of locality 22) bauxites have been found between malm and barremian–aptian limestones (sakač, 1969; sakač et al., 1969). lower cretaceous bauxites have been found in montenegro (stara crna gora – grubić, 1969), and w of nikšić (locality 7) bauxite deposits occur between barremian and upper cenomanian limestones (radoičić & vujisić, 1970; vujisić, 1972). bauxites between lower and upper cretaceous deposits in se slovenia (metlika, vinica) have been documented by buser & lukacs (1969). dragičević (1987) has determined that the largest bauxite deposits in the area of jajce in central bosnia (bešpelj– liskovica – locality 38c) occur between albian (or rarely cenomanian) limestones and rudist limestones of santonian age (fig. 2). a similar situation occurs in the area of grmeč mt. in w bosnia (e of locality 22), where in the footwall of the bauxites cenomanian limestones prevail, and they are overlain by santonian– campanian rudist limestones and clastic–carbonate flysch deposits of maastrichtian–palaeocene age (sakač, 1969; sakač et al., 1969). from istria, the northern adriatic islands, dalmatia and herzegovina to se montenegro, the most frequent bauxite deposits are located between cenomanian (more rarely turonian and santonian) limestones and palaeogene deposits (foraminiferal limestones and promina deposits); these bauxites are usually called “palaeogene bauxites” (sakač & šinkovec, 1991). 3.3. megafacies of peritidal–tidal flat pelletal and stromatolitic limestones forming shallowing-upward cycles (k–3) deposits of megafacies k–3 are mostly characterised by the alternation of thin-bedded pelletal wackestones/ packstones to grainstones and llh-stromatolites. they occur within all cretaceous chronostratigraphic units on the entire carbonate platform region. they often occur especially in the lower cretaceous of istria, dinara mt., biokovo mt., kamešnica mt., pelješac peninsula, dubrovnik area, wells kate–1 and boraja 1 (figs. 4–6) and the adriatic islands cres, korčula, mljet, i.e. localities 29, 34 and 35 (füchtbauer & tišljar, 1975; tišljar, 1978a, b, 1986; magaš, 152 geologia croatica 55/2 153tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... 1980; tišljar et al., 1983b; šebečić et al., 1983; tišljar & velić, 1986, 1991; velić et al., 1995; vlahović, 1999; husinec, 2002). in the lower cretaceous shallowing-upward cycles composed of pelletal or skeletal wackestones and llh-stromatolites with fenestral fabric and desiccation cracks within mudstone laminae are most frequent. skeletal wackestones are characterised by abundant greenalgae (especially salpingoporella dinarica), gastropods, ostracods and benthic foraminifera, among which palorbitolinas and mesorbitolinas are very important. these limestones were deposited in very shallow subtidal and intertidal flat environments (tišljar, 1978b; tišljar & velić, 1991; vlahović, 1999). in the upper cretaceous, deposits of megafacies k–3 very often occur on the entire carbonate platform within the middle and upper cenomanian and upper turonian to lower santonian deposits (figs. 4 & 6). good examples can be found in southern and northern istria – localities 1a, 1b (tišljar et al., 1983a, 1995, 1998; vlahović et al., 1994), the island of cres – locality 29 (mamužić et al., 1982; fuček et al., 1995), olib and ist islands – localities 26a–b (moro & jelaska, 1994), central and southern dalmatia (radovčić et al., 1983; mamužić et al., 1983), island of brač – locality 13 (jelaska & ogorelec, 1983; glovacki-jernej, 1988; gušić & jelaska, 1990), the island of hvar – locality 28 (mamužić et al., 1981) and the island of korčula – locality 34 (mamužić et al., 1980). in the upper cretaceous deposits the first member of a shallowing-upward cycle is usually foraminiferal– peloidal wackestone/packstone with green-algae thaumatoporella and aeolisaccus, in some places with chondrodonts mostly oriented parallel to the bedding planes and/or with rudist fragments. the upper member of each cycle is represented by laminated limestones (frequently late-diagenetic dolomitized), consisting of very thin microbacterial and mudstone laminae totally without fossil remains or containing very rare thaumatoporella and aeolisaccus remnants. during the late cretaceous within the peritidal parts of restricted shallows and lagoons with weak circulation and poor water aeration, i.e. oxygen deficiency, there are sporadic occurrences of “platy limestones with fishes”. they occur especially often in the turonian and senonian of the hinterland near primošten in central dalmatia (locality 37), the island of hvar (locality 28 – hemleben & freels, 1977; radovčić et al., 1983), and the cenomanian of western slovenia (komen limestones – ogorelec et al., 1987; jurkovšek et al., 1996; cavin et al., 2000). 3.4. megafacies of inner platform lagoonal and shallow subtidal oncoid and peloidal micritic limestones (k–4) within the cretaceous succession of the karst dinarides deposits of megafacies k–4 are the most widespread type, especially in the valanginian, hauterivian and lower aptian, but they are also very frequent in berriasian, barremian, lower albian, cenomanian, turonian and coniacian–lower campanian deposits (figs. 2, 4–6). they are represented by thick beds (0.4–3 m) or even massive mudstones, oncoid, pelletal and skeletal wackestones/packstones to floatstones. the limestones of megafacies k–4 were deposited in lagoons and restricted shallows in the inner part of the carbonate platform. in the lower cretaceous these limestones are mostly micritic rocks consisting predominantly of carbonate mud, i.e. micrite, and algal oncoids, faecal pellets, peloids and skeletons and/or bioclasts of restricted marine flora and fauna: green-algae (especially salpingoporella dinarica), gastropods, ostracods and micritized benthic foraminifera – primarily palorbitolinas and mesorbitolinas (šribar, 1979; koch, 1988; koch et al., 1989, 2002; tišljar & velić, 1991; turnšek et al., 1992). during the late cretaceous, limestones of megafacies k–4 were deposited within a complex pattern of lagoons and restricted shallows behind areas with abundant rudist and chondrodont communities and shallows characterised by the rapid deposition of bioclastic debris produced by these assemblages. micritic deposits of megafacies k–4 were therefore characterised by variable amounts of fine-grained rudist debris, peloids, benthic foraminifera, thaumatoporella, aeolisaccus and oncoids. within such a complex pattern of different small-scale environments rhythmical alternations characterised by shallowing-upward trend were deposited mostly by autocyclic mechanisms, usually composed of mudstones/wackestones with frequent thaumatoporella and aeolisaccus, rudist floatstones (sometimes in life-position as biostromes or thickets) and/or peritidal laminated limestones. alternations of this type are very common within cenomanian and senonian deposits throughout the karst dinarides (tišljar, 1978b; pleničar, 1979; mamužić et al., 1981, 1983, 1984; jelaska & ogorelec, 1983; gušić & jelaska, 1990; šribar & pleničar, 1990; vlahović, 1993; moro & jelaska, 1994; veseli, 1994; jurkovšek et al., 1996). within the upper albian inner platform, lagoonal and shallow subtidal oncoid and peloidal mud-bearing limestones of megafacies k–4 the occurrence of “quartz diagenetic sediments” (tišljar, 19854, 1994; vlahović et al., 2002a) or “quartz sediments” (šušnjara et al., 1971; galović, 1991) is very characteristic. they occur in central and southern istria (localities 1a, 1b), ćićarija mt. in ne istria (locality 4 tišljar, j. (1985): litološke i sedimentološke karakteristike podine, krovine i sloja kvarcnoga sedimenta u istri [lithology and sedimentology of the underlying and overlying limestones and quartz sediments in istria – in croatian].– unpubl. study, archive of the institute of geology zagreb, 87 p. 154 geologia croatica 55/2 155tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... w z w u o w en ::::l 0 w u « fw 0:: u 0:: w 00::::l en ::::l o w u « f­ w ~ z ~ ~ 2f wellkate-1 (komali area) .-<111 ... k-3,4,6 .-3 0:: i-~~=;c~~ u 0:: 12 well boraja-1 (tragir area) k-6 i~~~ ;; lk-4 ~k-3 megafacies units _ kp-1 k-8 t x ,=", k-7 t« ;~: l k-6 c ~ lower ~ albian • c -------cower ~ aptian ? barremian ilui p-3 p-2 ~.menlon 13 island ofbrac ...... ~ ~ 0 z w u 154 geologia croatica 55/2 155tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... 1c) and on the island of vis (locality 33), as well as authigenic quartz in dinara mt. (locality 10a) and svilaja mt. (se of locality 23). in earlier papers these deposits were known as “quartz sands” and “quartz sandstones” (polšak, 1965b, 1970) or “mechanochemogenic quartz sediments” (crnković, 1967). besides authigenic quartz and chalcedony they are composed of variable amounts of limestone relics, and in some places also well preserved silicified remains of green algae, benthic foraminifera, gastropods and bivalves. the origin of “quartz sediments” is probably connected with processes of early-diagenetic silicification of carbonate sediments, caused by the aeolian input of very fine volcanic ash mixed with carbonates, which was gradually dissolved in restricted alkaline lagoonal environments (tišljar, 19854, 1994, 2001; galović, 1991). 3.5. megafacies of intraclastic/peloidal and skeletal foreshore and shoreface grainstones and packstones (k–5) deposits of megafacies k–5 are predominantly composed of well-sorted and rounded intraclasts and/or peloids, benthic foraminiferal tests and in some places mollusc bioclasts (bivalves and gastropods). in the lower cretaceous succession of the karst dinarides megafacies k–5 is a typical megafacies unit in the upper albian of istria (fig. 3), lower aptian of the dinara mt. (locality 10a), upper aptian of biokovo mt. (locality 11), and the albian of the entire carbonate platform region, especially of the dinara mt., biokovo mt. and korčula island (locality 34) (fig. 5). well-sorted and rounded grains (intraclasts, peloids and miliolid tests), cross-lamination and cross-bedding, small-current ripples and wave ripples indicate the existence of foreshore and shoreface environments with agitated water, tidal channels and carbonate sand bars (tišljar et al., 1983b; tišljar & velić, 1991). in the upper cretaceous succession, deposits of megafacies k–5 occur only sporadically (fig. 6), e.g. in the kate–1 and boraja–1 wells (localities 2f and 12; veseli, 1994). 3.6. megafacies of rudist coquinas/coquinites with small rudist biostromes and lithosomes (k–6) deposits of megafacies k–6 are mostly composed of thick-bedded to massive floatstones, wackestones/packstones and rudstones. they usually contain a large quantity of rudist, and in some places chondrodont, debris of variable size, rounding and sorting, with very variable amounts of matrix and calcite cements. these deposits are very common in cenomanian, turonian and santonian–campanian deposits over the entire area of the mesozoic carbonate platform (figs.2, 4 and 6). alternations of rudist coquinas and thinner or thicker rudist biostromes and/or thickets with rudist shells in life position are common, and in some localities are even the predominant lithologies. during the late cretaceous, rudist assemblages, in some places accompanied by chondrodonts and gastropods, colonized vast areas of inner platform shallows and flourished along inner marginal areas towards intraplatform troughs and platform margins. for example, “rudist limestones” or rudist coquinas and thinner or thicker rudist biostromes and/or thickets with rudist shells in life position were described by polšak (1965b, 1970), mamužić et al. (1970, 1980, 1981, 1982, 1983), magaš (1973), pleničar (1973, 1974, 1975, 1977), tišljar (1978b), koch (1978, 1988), jelaska & ogorelec (1983), dragičević (1987), gušić & jelaska (1990), veseli et al. (1991), vlahović (1993, 1999), veseli (1994), vlahović et al. (1994, 2002b), moro & jelaska (1994), jurkovšek et al. (1996), pleničar & jurkovšek (1996, 1997, 1998, 2000a, b, 2001), koch et al. (1998), korbar et al. (2001, 2002), moro et al. (2002), tišljar et al. (2002a, b), etc. disintegration of rudist and chondrodont shells by bioerosion and other physical processes produced enormous quantities of bioclastic material, both coarsegrained which accumulated within shallows with agitated water, and fine-grained, well-sorted material within lagoons and platform margins. migration and accumulation of skeletal detritus was commonly very intensive, resulting in some places with the formation of clinoform bodies within high-energy foreshore– shoreface environments (tišljar et al., 1998). fine-grained detritus was redistributed by currents and waves, sometimes over large distances, and accumulated within low-energy inner platform deposits of megafacies k–4 or deeper environments characterised by pelagic fossil assemblages (megafacies k–7 and k–9a). along the n–ne margin of the platform, e.g. in nw and central bosnia, from the upper santonian to the maastrichtian there were occurrences of reefs and fig. 6 correlation of the cretaceous platform carbonate megafacies units of the adriatic area: well kate–1 (kornati), well boraja–1 (partly modified after veseli, 1994) and the island of brač (partly modified after gušić & jelaska, 1990). legend: p–3: megafacies of foraminiferal limestones; p–2: megafacies of peritidal/lagoonal stromatolitic, pelletal and skeletal micritic limestones; kp–1: megafacies of emersions with bauxites, and terrestrial, fresh-water and brackish (liburnian) deposits; k–8: megafacies of late-diagenetic dolomites; k–7: megafacies of limestones with pelagic fauna which originated during phases of temporary platform drowning; k–6: megafacies of rudist coquinas/coquinites with small rudist biostromes and lithosomes; k–5: megafacies of intraclastic/peloidal and skeletal foreshore and shoreface grainstones and packstones; k–4: megafacies of inner platform lagoonal and shallow subtidal oncoid and peloidal micritic limestones; k–3: megafacies of peritidal – tidal flat pelletal and stromatolitic limestones forming shallowing-upward cycles; k–2: megafacies of peritidal and vadose limestones, black-pebble breccia/conglomerates, emersion breccia, clays, swamp deposits and palaeosols, long-lasting emersions and bauxites. 156 geologia croatica 55/2 157tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... peri-reefal deposits composed of corals, hydrozoans, stromatoporoids and abundant rudists. destruction of these deposits produced enormous quantities of material, redeposited during the late cretaceous in the form of flysch deposits on platform slopes and in the proximal part of the basin (see megafacies k–9 and k–10 and dragičević & velić, 2002 – this vol.). 3.7. megafacies of limestones with pelagic fauna which originated during phases of temporary platform drowning (k–7) deposits of megafacies k–7 are most common around the cenomanian/turonian boundary and within the late santonian–campanian succession (figs. 4, 6). they are composed of micritic limestones with pelagic fossil assemblages, formed during temporary drowning of the platform caused by the interaction of eustatic sea-level rise and synsedimentary tectonics. because of the latter, the influence of eustatic changes was not constant over all areas of the platform. within lower cretaceous platform carbonates of the karst dinarides, the oldest pelagic fauna is recorded in the lower aptian deposits of the ogulin area in central croatia (locality 6c; velić & sokač, 1978). this episode represents evident pelagic influence during the deposition of lagoonal limestones with palorbitolinas, characterised by frequent hedbergellas and saccoccomas. the first late cretaceous pelagic episode is recorded within lower cenomanian deposits of the island of cres (locality 29; korbar et al., 2001). however, the most important are two regional episodes of platform drowning. older deposits of a drowned platform system (upper cenomanian–lower turonian) occur at numerous localities along the adriatic coast and islands (gušić & jelaska, 1990; 1993; fuček et al., 1990; veseli et al., 1991; tišljar et al., 1995, 1998; vlahović et al., 1994, 2002b; šribar, 1995; cavin et al., 2000). they are represented by thick-bedded, in some places nodular micritic limestones (mostly wackestones and packstones) containing calcisphaeres, rare crinoids, echinoderm remains and spicules of siliceous sponges, and very rare ammonites; in some places chert nodules are common. younger levels of megafacies k–7 deposits mostly correspond to the upper santonian–lower campanian. these micritic limestones, mudstones, wackestones and packstones, containing numerous pelagic fossils (calcisphaeres, globotruncanids) and fine rudist debris, are well-developed on the adriatic islands, especially the island of brač (locality 13 – gušić & jelaska, 1990) and island of dugi otok (locality 27 – fuček et al., 1990). 3.8. megafacies of late-diagenetic dolomites (k–8) deposits of megafacies k–8 are very frequent and occur in large bodies (figs. 4–6), especially at the beginning and at the end of the lower cretaceous – in the berriasian and albian of istria (locality 1), in the berriasian, valanginian and upper albian–lower cenomanian of the velika and mala kapela mts. (locality 6b), in the kordun and lika areas (south of locality 6a and between localities 4 and 3, respectively), in central dalmatia (murter–pirovac–vodice – between localities 25a and 37), dinara mt. (locality 10a), biokovo mt. (locality 11), the dubrovnik area (locality 18d), and the islands of cres, krk, dugi otok (localities 29, 30, 27), rava, pašman, prvić, zlarin (between localities 24 and 37), hvar, korčula and mljet (localities 28, 34, 35), and in the upper cretaceous of the islands of brač, wells kate–1 and boraja–1, and island of vis (localities 13, 2f, 12, 33). all the cretaceous examples are hypidiotopic and xenotopic mosaic macrocrystalline and/or microcrystalline dolomites with high ca-excess and a low degree of lattice ordering. they very often contain relics of more or less intensely dolomitized limestones of megafacies k–3, k–4, k–5 and k–6. however, late-diagenetic dolomites of megafacies k–8 are frequently dedolomitized or calcitized and transformed into microcrystalline “limestones of recrystallized texture”. this process is connected to the near surface zone, reaching a maximum at depths of 10 to 40 m, but also in the vicinity of intensely tectonized zones, since in these areas there is intense circulation of fresh-water, characterised by a low mg/ca molar ratio and rapid removal of mg2+ ions. 3.9. megafacies of slope carbonates: debrites and turbidites (k–9) deposits of megafacies k–9 mostly occur within the upper cretaceous, most frequently the upper santonian and campanian, in some places in deposits of maastrichtian age or transitional cretaceous–tertiary sequences along the platform margins, or along fault escarpments within the platform (fig. 2). they can be traced along the ne margin from the slovenian trough in the nw, through slovenia and central croatia, se of karlovac, slunj and bihać to central bosnia, herzegovina and montenegro. the best outcrops can be found in the area of karlovac–slunj–bihać–banjaluka– jajce–kupres (localities 6a, 4, 22, 39, 38b,c and 20), while along the sw margin they have been documented from offshore wells. megafacies k–9 can be subdivided into two types according to its lithological and sedimentological properties: – k–9a – carbonate debrites and coarse-grained carbonate turbidites, and 156 geologia croatica 55/2 157tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... – k–9b – middleto fine-grained carbonate turbidites or allodapic limestones. along the ne margin deposits of facies k–9a are represented by coarse-grained (2–60 cm) carbonate breccias composed of angular to subangular, weakly sorted clasts (up to small blocks) of shallow-water jurassic and cretaceous limestones and dolomites. these deposits are of albian to santonian–campanian age, and are, in all localities, covered by middleto fine grained carbonate turbidites (facies k–9b) and pelagic limestones and marls and campanian–palaeocene flysch deposits (dragičević, 1987; dragičević & velić, 1994), which are in this paper separated into megafacies k–10. for more information on the stratigraphic relationships and sedimentary environments along the ne margin of the adriatic carbonate platform see dragičević & velić (2002 – this vol.). in the area of the sw margin of the platform, deposits of megafacies k–9 have been found in numerous offshore wells in the northern and central adriatic. in the northern adriatic area, w and sw of istria in offshore wells, deposits of this megafacies are several hundred metres thick, e.g. a 740 m thick sequence in im–1 well (locality 2b), was deposited throughout the complete cretaceous and palaeogene periods. however, there are some exceptions (e.g. the 300 m thick sequence in j–86/1 – locality 2a, was deposited in a shorter time-interval – from the maastrichtian to the early eocene). generally, these deposits accumulated in environments ranging from carbonate platform, carbonate ramp with distributary channels and the transition into the basin plain (veseli, 1999). in the central adriatic area in an offshore well koraljka–1 (locality 32) a continuous sequence from the maastrichtian to the upper eocene was recorded within deep marine deposits of facies k–9b and megafacies k–10. these deposits consist of fossiliferous pelagic micrites and chalky limestones containing numerous planktonic foraminifera and nannoplankton (in some levels with cherts), and intercalations and thin beds of resedimented bioclastic limestones. this alternation of pelagic and bioclastic limestones were interpreted as carbonate turbidite deposits (lučić et al., 1993). fuček et al. (1991) documented resedimented middle turonian carbonate deposits (which could represent facies k–9b) in brbišnica cove on the island of dugi otok (locality 27) within a succession of pelagic limestones. 3.10. megafacies of calclithite–marly flysch (k–10) deposits of megafacies k–10 are predominantly composed of calclithite sandstones and marls forming typical bouma ta–d sequences. intervals ta–c are usually represented by calcirudites to calcisiltites, and td intervals by marls and silty marls. within such flysch deposits in some places, e.g. in the region of karlovac and the river vrbas in nw and central bosnia (figs. 1 & 2), there are occurrences of coarse-grained turbidites, i.e. breccias and breccio–conglomerates composed of poorly-sorted fragments, with or without large olistoliths of jurassic and cretaceous limestones and dolomites. these occurrences indicate synsedimentary tectonics with the formation of steeper slopes in the initial phase of flysch trough formation (dragičević & velić, 1994). deposits of megafacies k–10 were predominantly deposited from turbidity currents of low density, although occasionally there are deposits accumulated from high-density currents. in the deeper parts of the basin, farther from the mainland and islands deposition of carbonate muds took place in the same period. these mudstone and wackestone limestones contain pelagic fauna and grains of fine sand, silt or clay, and usually diagenetic chert nodules and layers. these are so-called “scaglia” limestones, which laterally and vertically gradually pass into flysch deposits (ogorelec et al., 1976). 4. carbonate and siliciclastic megafacies of the uppermost cretaceous and palaeogene deposits although the main topic of this paper is a discussion of jurassic and cretaceous deposits, we decided to add a short review of the overlying uppermost cretaceous and palaeogene deposits, to enable better insight into the post-platform evolution. cretaceous deposits are directly overlain by the following megafacies units (figs. 2, 4 and 6): kp–1: megafacies of emersions with bauxites, and terrestrial, fresh-water and brackish (liburnian) deposits, p–2: megafacies of peritidal/lagoonal stromatolitic, pelletal and skeletal micritic limestones, p–3: megafacies of foraminiferal limestones, and p–4: megafacies of pelagic limestones and carbonate turbidites – allodapic limestones. 4.1 megafacies of emersions with bauxites, and terrestrial, fresh-water and brackish (liburnian) deposits (kp–1) deposits of megafacies kp–1 comprise very variable rocks, united by their non-marine environments of origin, either during long-lasting emersion with or without bauxites, or within fresh-water or brackish environments before the final palaeogene transgression. non-marine conditions prevailed for very variable periods of time in different parts of the former carbonate platform. the emersion commenced at different times (mostly from the cenomanian to san158 geologia croatica 55/2 159tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... tonian, rarely to the maastrichtian, but in some parts it had already started in the early cretaceous), while the palaeogene transgression in the croatian parts of the karst dinarides started mostly in the early eocene. additionally, it is not easy to speculate on the proportion of the former carbonate platform, which was covered by the palaeogene sea, because in this period the area was morphologically diverse. in the northern adriatic area (im and j wells – locality 2b–c, fig. 1) the youngest cretaceous deposits are of upper cenomanian age, and are covered by pliocene deposits (veseli, 1999). in northern istria, (locality 1b) emersion occurred from the cenomanian (savudrija–buzet anticline, lower part of the učka mt.), coniacian (ćićarija mt. – locality 1c) to the santonian (top of the učka mt.). in central istria there are several occurrences of palaeogene limestones covering lower cretaceous deposits (valanginian, hauterivian, barremian, and albian – matičec et al., 1996), and depressions in the palaeorelief of karstified cenomanian limestones are filled by bauxites and brackish palaeogene liburnian deposits (marinčić & matičec, 1989), while in southern istria the youngest cretaceous rocks are of upper santonian age (moro et al., 2002). in the northern part of the island of cres (locality 29) bauxites overlie upper cenomanian deposits, while in the southern part the youngest cretaceous deposits are of turonian–coniacian age or even slightly younger (korbar et al., 2001). on the island of krk (locality 30) bauxites cover upper cenomanian to lower turonian deposits, while on the islands of lošinj and pag (localities 31a and 31b) the youngest cretaceous deposits are of senonian age, similar to the situation in the ravni kotari area. in dalmatia and herzegovina emersion commenced differently from place to place, and bauxites, if present, and palaeogene fresh-water, brackish and marine deposits cover emerged and more or less palaeokarstified upper cretaceous rocks of different stratigraphic levels – from the cenomanian to the maastrichtian. on the island of brač (locality 13) there are outcrops of maastrichtian rocks (gušić & jelaska, 1990), and in herzegovina bauxites and brackish deposits cover turonian–senonian limestones (dragičević et al., 1992). bauxite deposits occur as sedimentary bodies of various shapes and sizes. they were formed in palaeorelief recesses on the underlying limestones and represent a regional palaeogeographical and sedimentological marker connected with emersion phases. their stratigraphic position – as defined by the age of underlying and overlying rocks – is very variable. liburnian deposits resulted from oscillatory ingression, and are mostly represented by fresh-water and brackish deposits of lower eocene age composed of alternating layers of gastropod wackestones/packstones and algal wackestones, and occasionally bivalve floatstones or packstones and microcodium-bearing wackestones/mudstones. they were deposited only in the lowermost parts of the palaeorelief. at some localities in sw slovenia there is almost a continuous succession from the cretaceous to the palaeogene (drobne et al., 1989, 1998; drobne, 1979; delvalle & buser, 1990; ogorelec et al., 1995, 2001; jurkovšek et al., 1996, 1997; pugliese et al., 1995), but in croatia palaeocene rocks are practically missing (drobne, 1977; drobne et al., 1991, 2000; ćosović & drobne, 1998; velić et al., 2002c), and maastrichtian deposits are relatively rare. 4.2. megafacies of peritidal/lagoonal stromatolitic, pelletal and skeletal micritic limestones (p–2) deposits of megafacies p–2 represent the first palaeogene marine deposits, in some places overlying a sequence of megafacies kp–1, while elsewhere they represent the oldest palaeogene rocks infilling the lowest parts of the palaeorelief. they are characterised by the alternation of laminated and/or thin-bedded wackestones/mudstones with characean gyrogonnites and frequent microcodium with llh-stromatolites and miliolid wackestones deposited in intertidal and shallow subtidal environments (ogorelec et al., 2001). 4.3. megafacies of foraminiferal limestones (p–3) deposits of megafacies p–3 can be subdivided into four lithostratigraphic types, mostly deposited from the early to middle eocene, named after the prevailing biota as miliolid limestones, alveolinid limestones, nummulite limestones and discocyclinid limestones. since these facies units penecontemporaneously occupied different environments, from restricted shallows to carbonate slopes in the investigated carbonate successions characterised by a general transgressive trend, they are mostly in superpositional relations. foraminiferal limestones are mostly composed of the complete and disintegrated tests of benthic foraminifera, while the detritus of molluscs, echinoderms and bryozoans, as well as glauconite in the uppermost (i.e. youngest) part, are subordinate. such a composition is typical of a foramol association. miliolid limestones represent the restricted inner part of the carbonate platform, alveolinid limestones and nummulite limestones the shallower and deeper parts of shoreface environments and discocyclinid limestones the deeper parts of relatively open carbonate ramps. the same types in different areas are usually of somewhat different ages, but a general deepening-upward trend is always present. this trend is a consequence of the interaction of several causes, mainly intense synsedimentary tectonics (restricting the carbonate factory to the relatively narrow zones along the basin margins and ensuring appropriate accommodation space was available for the redistribution of shallowwater material to the basin), and relatively low net 158 geologia croatica 55/2 159tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... sedimentation rate as a consequence of deposition in environments which were no longer ideal for biogenic carbonate production. additionally, large quantities of foraminiferal tests and their remains were resedimented into the deeper parts of the basin by turbidity currents. deposits of this megafacies are most common in the coastal area and hinterland of the karst dinarides, especially in sw slovenia (pavlovec, 1963; drobne, 1977; drobne & pavlovec, 1991), along the adriatic coast in croatia (central and n istria – locality 1, vinodol area – locality 24, dalmatia and adriatic islands) in herzegovina and se montenegro. 4.4. megafacies of pelagic limestones and carbonate turbidites – allodapic limestones (p–4) deposits of megafacies p–4 are composed of mud-supported pelagic limestones and intercalations of thinner or thicker calcarenite layers. in the lowermost part they are usually characterised by the so-called “transitional beds” – marls with frequent crabs and glauconite grains. megafacies p–4 rocks are common along the adriatic coast, on islands and in western herzegovina (e.g. mamužić & sokač, 1973; mamužić, 1975; marinčić, 1981; babić & zupanič, 1990; babić et al., 1993), as well as in numerous offshore wells, e.g. j–86/1 and im–1, 2, 3, 4 and 5 (localities 2a and 2b – veseli, 1999), and koraljka–1 (locality 32 – lučić et al., 1993). similar deposits also occur along the ne platform margin (dragičević, 1987; dragičević & velić, 1994). pelagic limestones of mudstone, wackestone to packstone types contain a rich planktonic fauna (especially planktonic foraminifera) and variable amounts of very fine-grained detritus. usually they have thin intercalations of calcarenites with variable amounts of siliciclastic grains. this alternation can be interpreted as fine-grained or muddy carbonate turbidites of a piper type. in some localities within pelagic limestones and marls there are 5–20 cm (in some places several metres thick) calcarenite beds deposited from gravitational flows, representing ta–c and tb–c intervals of bouma sequences of middle-grained carbonate turbidites or allodapic limestones. these beds contain a large quantity of fine-grained carbonate detritus (complete and disintegrated benthic foraminifera tests, as well as bioclasts of echinoderms, molluscs, peloids, intraclasts, etc.), transported from marginal areas of the flysch basin. in some areas pelagic and allodapic limestones contain chert nodules, e.g. in northern adriatic offshore wells (localities 2a and 2b – veseli, 1999). 6. disscusion and conclusions the lateral and vertical pattern of different megafacies, their thickness and the duration of sedimentary conditions suitable for their origin, provide very important data on the palaeogeomorphological evolution of the carbonate platform. penecontemporaneous occurrences of different megafacies on different parts of the carbonate platform during the long period studied, from the jurassic to the middle eocene, clearly indicate the diverse environments and depositional conditions present during the same periods (fig. 7). additionally, deposits of the same megafacies units in different areas are commonly characterised by the variable duration of similar conditions. this is especially true for the late cretaceous and palaeogene (characterised by the final disintegration of the platform). however, even during a period of optimal platform development, approximately from the lias to the albian, there are numerous examples of facies variation in the platform realm. minor changes of platform conditions and environments represented the consequence of various factors, e.g. variable accumulation and subsidence rates, changes in water-energy, variability of local morphology, influence of sporadic storms and ecological changes controlling the different roles of organisms in the production of skeletal and non-skeletal allochems. however, interference of small changes in different factors within such a complex sedimentary system of the carbonate platform produced very important changes in sedimentary record. in some periods regressive tendencies resulted in shorter or longer emersions recorded in different areas of the platform – practically throughout the entire studied stratigraphic range a smaller or larger area of the platform was emerged at any given time (fig. 7): – from the middle lias to kimmeridgian a large area from trnovski gozd (locality 5f) and suha krajina (locality 5a) in slovenia, through central croatia (karlovac area – locality 6a) and from nw to central bosnia and central montenegro; – from the oxfordian to the late tithonian in southern slovenia (suha krajina, nanos, hrušica, logaška planota – localities 5a, c, d and e), in croatia (western istria – locality 1a, and biokovo mt. – locality 11), in bosnia and herzegovina (drvar, srnetica mt., glamoč and trebinje area – localities 14–17) and in montenegro (nikšić and cetinje area – localities 7 and 9); – from the late tithonian to the valanginian in the dinara mt. and kamešnica mt. (localities 10a and 10b), and from the late kimmeridgian to the barremian in grmeč mt. in w bosnia (e of locality 22). – from the early or late aptian to the middle albian in western and central istria (locality 1), but also shorter 160 g eologia c roatica 55/2 161 tišljar, v lahović, velić & s okač: c arbonate p latform m egafacies of the jurassic and c retaceous d eposits... hiatuses (late a ptian to early a lbian) at num erous other localities on the a driatic c arbonate platform ; – from the late triassic, late m alm , b arrem ian, a ptian and a lbian to the santonian–c am panian along the northern platform m argin in b osnia (b anjaluka–d . b ešpelj–jajce–janj–k upres – localities 39, 38c-b-a and 20); – from the c enom anian, turonian, santonian–c am fig. 7 tim e distribution of long-lasting em ersions (terrestrial conditions) and jurassic, c retaceous and p alaeogene units of the k arst d inarides (tim e scale after g r a d s te in & o g g , 1996). k -7 jurassic cretaceous tertiary m .... lei eocene i localities r[1 i i i i· 1~1 ... 1 lie i ~~~~ol ,,,,,,,;;, .. ,.,'7 ,''''''!,,,,, •• 5f •••• 7 .• ~ i i w. j 1 ........... q 1l17 • regional ""i'"""i"""i"~~~""i'"-'" 10c8~1ly 108 i~iities 1~ lind 1~ i •• ~.~.liily.,.. .. ~i!i!i.~ or;9 '" ::i. 0'" od. ::i!il. high-<>nergy sl10als ana bars ~, ~ ::i. m i!l: trough g~ .,0 :i"i ~q~~hi ~ t rti i'tn c;~ , f------i~ vi~h--hf'i\ ~ ~~~/ -8--t-l-r-~----~ ---~-i-rl-~-"""-'-' ~ ~t rr rnncalily 6c p . p~ ii~ late>ii diagen.etic t dolomites ~ ~ i ~ i@i ~~ i ~ i i ~ i i ~l;j i i ii ~ ~ 13.bi 6.b i 5.71 9.5 3.61 7.3 14.b 15.0 15.313.41 b.b 15.414.515.0 i b.o i b.b 13.3 5.414.513.2~.3 12.2 i 6.3 i 10.1 ~~-~~---~~(---~>-i~----~-~--~~--~25.b m.y. 20.7 m.y. 17.5 m.y. 43.0 m.y. 33.9 m.y. b3.b m.y. 77.0 m.y. 3. ~• 160 geologia croatica 55/2 161tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... panian or maastrichtian to the eocene in the entire coastal area and adriatic islands, as well as in western herzegovina. in istria there are some localities with stratigraphic hiatus from the valanginian, hauterivian, barremian or albian to the eocene. the opposite situation is recorded in periods characterised by eustatic sea-level rise resulting in establishment of drowned platform environments (megafacies k–7), e.g. near the cenomanian/turonian boundary or from the late turonian–santonian to the earliest campanian. however, both the aforementioned regionally important phases of emersion and platform drowning had different consequences on different parts of the adriatic carbonate platform, since the regional or global eustatic signal was significantly corrected by local factors, especially synsedimentary tectonics. although the influence of synsedimentary tectonics on the carbonate platform is rarely clearly visible, especially because of the high organic production enabling fast infilling of any available accommodation space, its understanding is essential for the correct interpretation of the geological history of the platform. by careful examination of different penecontemporaneous successions it is possible to extract the tectonic signal resulting in the formation of environments which otherwise would not be possible. a very good example of the influence of synsedimentary tectonics can be seen in the upper jurassic successions in different parts of the karst dinarides. the latest oxfordian (or earliest kimmeridgian) was, in the area of present istria (locality 1a on fig. 1), characterised by the beginning of the long-lasting emersion – shallow-marine deposition recurred in the late tithonian, i.e. practically the complete kimmeridgian and lower tithonian deposits are missing. at biokovo mt. (locality 11) there are two emersions: from the early oxfordian to the early kimmeridgian and from the late kimmeridgian to the middle tithonian, divided by a relatively thin sequence of kimmeridgian deposits (tišljar & velić, 1991). in the same period the western part of the gorski kotar area (platak–gornje jelenje and zlobin – localities 6d and 6f) was characterised by continuous shallow-water sedimentation, while in its eastern part (velika kapela mt. and senj–ogulin area, localities 6b–c) an intraplatform trough was formed. it was characterised by deposition of limestones with cherts (megafacies j–8 – see velić et al., 2002b for more information). somewhat deeper marine environments in this area prevailed only temporarily – intense progradation of calcitic detritus (ooids, intraclasts, and especially peri-reefal bioclasts) from marginal areas gradually filled in the sedimentary basin, resulting in the final recovery of shallow-water deposition in tithonian (megafacies j–5, j–6, j–7 and j–2). along the northern margin the kimmeridgian was characterised by a transgression over an area emergent for a long period (emersion started in the middle lias). such variability in the sedimentary record definitely cannot be interpreted without the important influence of local synsedimentary tectonics. namely, the oxfordian deposits are more or less similar throughout the area, while during the kimmeridgian completely different environments were formed. some parts were affected by emersion, in others shallow-marine deposition continued, some parts were characterised by deepening and an open marine influence, while in others transgression over areas which had been exposed for a long time was recorded. tithonian successions are again similar throughout the area, represented mostly by shallowwater algal limestones. an interesting example of the influence of extensive organic production on a carbonate platform is provided by a study of late cretaceous environments colonized by flourishing rudist communities. according to their ecological preferences, different rudist types usually accompanied by different molluscs (mostly chondrodonts and nerineids) occupied a wide range of different environments, from the inner, restricted parts of the platform, shallows with agitated water, somewhat deeper lagoons and inner parts of the platform margins. their carbonate production was very high, and the material produced by disintegration of their skeletons by bioerosion and mechanical processes represented an important part of the total carbonate production in the late cretaceous. this material was reworked and continuously removed to other areas by waves and currents, enabling infilling of former smaller or larger depressions and the formation of a variable sea-bottom morphology by different mechanisms, e.g. migration of subaqueous dunes, but also transportation to far distances by turbidity currents. in this way organic production interacted with the environment, since it was influenced by its environment, but also the environment was significantly changed by organic production. the very complex vertical and lateral alternation of different megafacies units therefore indicate the significant palaeogeographical dynamics of the karst dinarides. this variability resulted from the interaction of a global eustatic signal and local factors, first of all extensive organic production on carbonate platform and synsedimentary tectonics controlled by the specific palaeogeographic position of the platform during its geological history. acknowledgement the authors are sincerely grateful to the reviewers, dr. bojan ogorelec and dr. bogdan jurkovšek (geological survey of slovenia) for their numerous comments and useful suggestions, especially concerning data on the slovenian part of the adriatic carbonate platform. 162 geologia croatica 55/2 163tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... 7. references ahac, a., papeš, j. & raić, v. (1977): osnovna geološka karta sfrj 1:100.000. list glamoč l33–142 (basic geologic map of sfry 1:100.000 – the glamoč sheet).– geološki zavod sarajevo (1963–1965), savezni geol. zavod beograd. antonijević, r., pavić, a. & karović, j. (1969): osnovna geološka karta sfrj 1:100.000. list kotor k34–50 (basic geologic map of sfry 1:100.000 – the kotor sheet).– zavod za geol. geofiz. istraž. beograd (1962–1969), savezni geol. zavod, beograd. babić, lj. & zupanič, j. (1990): progradacijski slijedovi u paleogenskom klastičnom bazenu vanjskih dinarida, od sjeverne dalmacije do zapadne hercegovine (progradational sequences in the paleogene clastic basin of outer dinarids, from nothern dalmatia to western herzegovina).– rad jazu, 449, 319–343, zagreb. babić, lj., zupanič, j. & crnjaković, m. (1993): an association of marine tractive and gravity flow sandy deposits in the eocene of the nw part of the island of pag (outer dinarides, croatia).– geol. croatica, 46/1, 107–123. bachofen–echt, a. (1925): iguanodon-fährten auf brioni.– paläont. zeitsch., 7/7, 172–173. bahun, s. (1985): trijaske naslage i jelar-formacija u dolini une između srba i brotnje (hrvatska) (triassic deposits and jelar-formation in the una valley between srb and brotnja (croatia)).– geol. vjesnik, 38, 21–30. blašković, i. (2001): karbonatna platforma ili karbonatne platforme dinarida (the “carbonate platform” or “carbonate platforms” of the karst dinarides).– in: dragičević, i. & velić, i. (eds.): 1. znanstveni skup “karbonatna platforma ili karbonatne platforme dinarida” (1st scientific meeting “carbonate platform or carbonate platforms of dinarides”), knjiga sažetaka (abstracts). rgnf, pmf & igi, 8, zagreb. bucković, d. (1995): upper jurassic carbonate facies succession at breze (velika kapela, croatia).– geol. croatica, 48/1, 9–16. bukovac, j., velić, i. & sokač, b. (1974): stratigrafski, tektonski i paleogeografski odnosi u području dugarese, barilovića i skradske gore (stratigraphy, tectonics and palaeogeography of the region between duga resa, barilović and skradska gora, croatia).– geol. vjesnik, 27, 59–77. bukovac, j., poljak, m., šušnjar, m. & čakalo, m. (1984): osnovna geološka karta sfrj 1:100.000. tumač za list črnomelj l33–91 (basic geologic map of sfry 1:100.000 – geology of the črnomelj sheet).– geološki zavod zagreb, geološki zavod ljubljana (1972– 1983), savezni geol. zavod, beograd, 63 p. buser, s. (1969): osnovna geološka karta 1:100.000. list ribnica l33–78 (basic geologic map of sfry 1: 100.000, the ribnica sheet).– geološki zavod ljubljana (1961–1965), savezni geološki zavod beograd. buser, s. (1978): razvoj jurskih plasti trnovskega gozda, hrušice in logaške planote (the jurassic strata of trnovski gozd, hrušica and logaška planota).– rud. met. zb., 4, 385–406, ljubljana. buser, s. (1979): jurassic beds in slovenia.– in: drobne k. (ed.): guidebook of 16th european micropaleontological colloquium. 27–36, ljubljana. buser, s. (1989): development of the dinaric and the julian carbonate platforms and of the intermediate slovenian basin (nw yugoslavia).– mem. soc. geol. ital., 40, 313–320. buser, s. & debeljak, i. (1996): lower jurassic beds with bivalves in south slovenia.– geologija, 37–38, 23–62, ljubljana. buser, s. & lukacs, e. (1969): bauxite in slowenien.– annales instituti geologici publici hungarici, 54/3, 209–220. buser, s., grad, k. & pleničar, m. (1967): osnovna geološka karta sfrj 1:100.000. list postojna l33–77 (basic geologic map of sfry 1:100.000, the postojna sheet).– geološki zavod ljubljana (1963), savezni geol zavod beograd. cavin, l., jurkovšek, b. & kolar-jurkovšek, t. (2000): stratigraphic succession of the upper cretaceous fish assemblages of kras (slovenia).– geologija, 43/2, 165–195, ljubljana. crnković, b. (1967): quartz sedimente in istrien – produkte der kieselsäurefällung.– ber. deutsch. ges. geol. wiss. b. miner. lagersttatenf., 12/2, 181–186. ćosović, v. & drobne, k. (1998): lutetian orthopragminae from the istrian peninsula (adriatic sea, croatia and slovenia).– dela – opera sazu, classis iv, 34/2, 173–181, ljubljana. dalla vecchia, f.m. (1998): remains of sauropoda (reptilia, saurischia) in the lower cretaceous (upper hauterivian/lower barremian) limestones of sw istria (croatia).– geol. croatica, 51/2, 105–134. dalla vecchia, f.m. & tarlao, a. (1995): dinosaur evidence in the cretaceous of istria (croatia).– in: vlahović, i., velić, i. & šparica, m. (eds.): 1. hrvatski geološki kongres, zbornik radova (first croatian geological congress, proceedings), 1, 151–154, zagreb. dalla vecchia, f.m., tarlao, a. & tunis, g. (1993): theropod (reptilia, dinosauria) footprints in the albian (lower cretaceous) of the quieto/mirna river mouth (nw istria, croatia) and dinosaur population of istrian region during the cretaceous.– mem. sci. geol., 45, 139–148, padova. dalla vecchia, f.m., tarlao, a., tentor, m., tunis, g. & venturini, s. (2000a): first record of hauterivian dinosaur footprints in southern istria (croatia).– in: vlahović, i. & biondić, r. (eds.): zbornik radova 2. hrvatskog geološkog kongresa (proceedings of the second croatian geological congress). 143–149, zagreb. dalla vecchia, f.m., tarlao, a., tunis, g. & venturini, s. (2000b): new dinosaur track sites in the albian (early cretaceous) of the istrian peninsula (croatia).– mem. sci. geol., 52/2, 193–292, padova. dalla vecchia, f.m., vlahović, i., posocco, l., tarlao, a. & tentor, m. (2002): late barremian and late albian (early cretaceous) dinosaur track sites in the main brioni/brijun island (sw istria, croatia).– natura nascosta, 25, 1–36, monfalcone. 162 geologia croatica 55/2 163tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... d’argenio, b., radoičić, r. & sgrosso, i. (1971): a paleogeographic section through the italo–dinaric external zones during jurassic and cretaceous times.– nafta, 22/4–5, 195–207, zagreb. debeljak, i. & buser, s. (1998): lithiotid bivalves in slovenia and their mode of life.– geologija, 40, 11–64, ljubljana. debeljak, i., košir, a. & otoničar, b. (1999): a preliminary note on dinosaurs and non-dinosaurian reptiles from the upper cretaceous carbonate platform succession at kozina (kras, sw slovenia).– razprave iv. razr. sazu, 40, 3–25, ljubljana. debeljak, i., košir, a., buffetaut, e. & otoničar, b. (2002): the late cretaceous dinosaurs and crocodiles of kozina (sw slovenia): a preliminary study.– mem. soc. geol. ital., 57/1, 193–202, roma. delvalle, d. & buser, s. (1990): mikrofacies analysis of limestone from the upper cretaceous to the lower eocene of sw slovenia (yugoslavia).– geologija, 31/32 (1988/89), 351–394, ljubljana. dini, m., tunis, g. & venturini, s. (1998): continental, brackish and marine carbonates from the lower cretaceous of kolone–barbariga (istria, croatia): stratigraphy, sedimentology and geochemistry.– palaeogeography, palaeoclimatology, palaeoecology, 140, 245–269. dozet, s. (1992a): litostratigrafske enote in značilne mikrofacije kočevske jure (lithostratigraphic units and significant microfacies of the kočevje jurassic).– rud. met. zb., 39/3–4, 287–305, ljubljana. dozet, s. (1992b): litostratigrafija, diageneza, sedimentacijsko okolje in geokemija jurskih plasti na listu delnice (lithostratigraphy, diagenesis, environment and geochemistry of the jurassic beds on the delnice sheet).– rud. met. zb., 39/1–2, 193–210, ljubljana. dozet, s. (1994): stratigraphy of the suha krajina area (slovenia) and stratigraphic gap middle liassic–lower malm.– rudarsko–metalurški zbornik, 41, 231–238, ljubljana. dozet, s. (1995): the malm algal nodules (oncolites) from the suha krajina region (slovenia).– rudarsko–metalurški zbornik, 42/3–4 165–169, ljubljana. dozet, s. (2000): kočevje oolitic group, central slovenia.– acta carsologica, 29/1, 185–199, ljubljana. dozet, s. & mišič, m. (1997): on malm bauxites and adjacent carbonate rocks in suha krajina (central slovenia).– rudarsko–metalurški zbornik, 44/3–4, 201–222, ljubljana. dozet, s. & šribar, lj. (1998a): biostratigraphy of shallow marine jurassic beds in southeastern slovenia.– geologija, 40, 187–221, ljubljana. dozet, s. & šribar, lj. (1998b): lower cretaceous shallow marine sedimentation and biota on dinaric carbonate platform between logatec, krka and kolpa (southeastern slovenia).– geologija, 40, 153–185, ljubljana. dragičević, i. (1987): paleogeografska evolucija rubnog dijela mezozojske karbonatne platforme dinarida između vrbasa i bosne (palaeogeographical evolution of the marginal zone of the mesozoic carbonate platform of dinarides in the area between vrbas and bosna rivers).– unpubl. phd thesis, university of zagreb, 90 p. dragičević, i. & velić, i. (1994): stratigraphical position and significance of reef facies at the northern margin of the dinaric carbonate platform during the late jurassic and cretaceous in croatia and bosnia.– géologie méditerranéenne, 3–4, 59–63. dragičević, i. & velić, i. (2002): the northeastern margin of the adriatic carbonate platform.– geol. croatica, 55/2, 185–232. dragičević, i., blašković, i., tišljar, j. & benić, i. (1992): stratigraphy of paleogene strata within the mesihovina–rakitno area (western herzegovina).– geol. croatica, 45, 25–52. drobne, k. (1977): alvéolines paléogènes de la slovénie et dell’istrie.– mem. suiss. paleont., 99, 175 p. drobne, k. (1979): paleogene and eocene beds in slovenia and istria.– gudebook of the 16th europ. micropal. coll., ljubljana, 49–63. drobne, k. & pavlovec, r. (1991): paleocene and eocene beds in slovenia and istria.– igcp project 286 – early paleogene benthos, 2nd meeting postojna, 7–17, ljubljana. drobne, k., ogorelec, b., pleničar, m., barattolo, f., turnšek, d. & zucchi–stolfa, m.l. (1989): the dolenja vas section, a transition from cretaceous to paleocene in the nw dinarides, yugoslavia.– mem. soc. geol., ital., 40 (1987), 73–84, roma. drobne, k., vlahović, i., trutin, m., pavlovec, r., ćosović, v., babac, b., cimerman, f., lučić, d. & pavšič, j. (1991): excursion b – ravni kotari – paleogen.– in: vlahović, i. & velić, i. (eds.): some aspects of the shallow water sedimentation on the adriatic carbonate platform (permian to eocene). excursion guide–book, 2nd internat. symposium on the adriatic carbonate platform, institute of geology, zagreb, 53–107. drobne, k., ogorelec, b., pleničar, m., zucchistolfa, m. l. & turnšek, d. (1998): maastrichtian, danian and thanetian beds in dolenja vas (nw dinarides, yugoslavia) – microfacies, foraminifers, rudists and corals.– razprave sazu, 4. razr., 29, 147–224, ljubljana. drobne, k., pugliese, n. & trutin, m. (2000): correlation of palaeocene biota of the north adriatic karst area and herzegovina.– in: vlahović, i. & biondić, r. (eds.): 2. hrvatski geol. kongr. (2nd croatian geological congress), cavtat–dubrovnik, zbornik radova (proceedings), 167–170, zagreb. durn, g., ottner, f., tišljar, j., schwaighofer, b., fröschl, h. & ćović, m. (2000): mineraloški, mikromorfološki i geokemijski pokazatelji pedogenetske prirode glina vezanih na regionalnu emerziju u mlađem aptu i starijem albu u istri, hrvatska (mineralogical, micromorphological and geochemical indications of pedogenetic clay nature within the regional emersion in the late aptian and early albian in istria).– in: vlahović, i. & biondić, r. (eds.): 2. hrvatski geol. kongr. (2nd croatian geological congress), cavtat–dubrovnik, zbornik radova (proceedings), 503–504, zagreb. 164 geologia croatica 55/2 165tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... farinacci, a. & radoičić, r. (1964): correlazioni fra le serie giuresi e cretacee dell’apennino centrale e delle dinaridi esterne.– ricerca sci. (rendiconti), 34, 269–300. fuček, l., gušić, i., jelaska, v., korolija, b. & oštrić, n. (1990): stratigrafija gornjokrednih naslaga jugoistočnoga dijela dugog otoka i njihova korelacija s istovremenim naslagama otoka brača (upper cretaceous stratigraphy of the se part of the dugi otok island and its correlation with the corresponding deposits of the brač island, adriatic carbonate platform).– geol. vjesnik, 43, 23–33. fuček, l., jelaska, v., gušić, i., prtoljan, b. & oštrić, n. (1991): padinski turonski sedimenti uvale brbišnica na dugom otoku (turonian slope deposits in the brbišnica cove, dugi otok island, croatia).– geol. vjesnik, 44, 55–67. fuček, l., velić, i., vlahović, i., oštrić, n., korolija, b. & matičec, d. (1995): novi podaci o stratigrafiji donje krede otoka cresa (new data on the lower cretaceous stratigraphy of the island of cres).– in: vlahović. i., velić, i. & šparica, m. (eds.): zbornik radova 1. hrvatskog geološkog kongresa (1st croatian geol. congress, proccedings), 1, 167–172, zagreb. füchtbauer, h. & tišljar, j. (1975): peritidal cycles in the lower cretaceous of istria (croatia, yugoslavia).– sedimentary geology, 14, 219–233. galović, i. (1991): geološki položaj i geneza kvarcnih sedimenata istre (geological position and origin of quartz sediments in istria).– unpubl. phd thesis, university of zagreb, 119 p. glovacki-jernej, ž. (1988): lovrečina emerzija u kampan–mastrihtu otoka brača (lovrečina emersion in the campanian–maastrichtian of the island of brač).– geol. glasnik, posebno izd., 6, zbornik radova 6. skupa sedimentologa jugosl., 57–65, titograd. grandić, s. (1974): neke naftnogeološke karakteristike vanjskih dinarida (some petroleum-geological characteristics of the outer dinarids).– nafta, 25/3, 111–120, zagreb. gradstein, f.m. & ogg, j.g. (1996): a phanerozoic time scale.– episodes, 19/1–2, 3–4. grubić, a. (1969): les bauxites de yougoslavie.– annales instituti geologici publici hungarici, 54/3, 195–207. gušić, i. & jelaska, v. (1990): stratigrafija gornjokrednih naslaga otoka brača u okviru geodinamske evolucije jadranske karbonatne platforme (upper cretaceous stratigraphy of the island of brač within the geodinamic evolution of the adriatic carbonate platform).– jazu and inst. geol. istraživanja, zagreb,160 p. gušić, i. & jelaska, v. (1993): upper cenomanian–lower turonian sea-level rise and consequences on the adriatic–dinaric carbonate platform.– geol. rundsch., 82/4, 676–686. hemleben, c.h. & freels, d. (1977): algen-laminierte und gradierte plattenkalke in der oberkreide dalmatiens (jugoslawien).– n. jb. geol. paläont. abh., 154/1, 61–93. herak, m. (1973): some tectonical problems of the evaporitic area in the dinarides of croatia.– geol. vjesnik, 26, 29–40. herak, m. (1983): some ideas and dilemas concerning the genesis and tectonics of the adriatic and periadriatic areas.– in: babić, lj. & jelaska, v. (eds.): contributions to sedimentology of some carbonate and clastic units of the coastal dinarides. 4th ias regional meeting, excursion guide-book, 7–11, split. herak, m. (1986): a new concept of geotectonics of the dinarides.– acta geologica, 16/1, 1–42, zagreb. herak, m. (1989): relationship between adriatic and dinaric platforms.– mem. soc. geol. ital., 40, 289–293, roma. herak, m. (1991): dinarides – mobilistic view of the genesis and structure.– acta geologica, 21/2, 35–117, zagreb. herak, m. (1993): additional considerations on the epiadriaticum, outer dinarides.– geol. croatica, 46/1, 165–168. husinec, a. (2002): stratigrafija mezozojskih naslaga otoka mljeta u okviru geodinamske evolucije južnoga dijela jadranske karbonatne platforme (mesozoic stratigraphy of the island of mljet within the geodynamic evolution of the southern part of the adriatic carbonate platform).– unpubl. phd thesis, university of zagreb, 300p. husinec, a., velić, i., fuček, l., vlahović, i., matičec, d., oštrić, n. & korbar, t. (2000): mid-cretaceous orbitolinid (foraminiferida) record from the islands of cres and lošinj (croatia) and its regional stratigraphic correlation.– cretaceous research, 21, 155–171. ivanović, a., sikirica, v., marković, s. & sakač, k. (1977): osnovna geološka karta sfrj, 1:100.000. list drniš k33–9 (basic geologic map of sfry 1:100.000 – the drniš sheet).– inst. geol. istraž. zagreb (1967–1972), savezni geol. zavod beograd. ivanović, a., sikirica, v. & sakač, k. (1978): osnovna geološka karta sfrj, 1:100.000. tumač za list drniš k–33–9 (basic geologic map of sfry 1:100.000 – geology of the drniš sheet).– inst. geol. istraž. zagreb (1972), savezni geol. zavod beograd, 59 p. jelaska, v. (1973): paleogeografska i naftnogeološka razmatranja zapadnog dijela karbonatnog šelfa dinarida (paleogeographical and petroleum–geological considerations of the western part of the dinaric carbonate shelf).– geol. vjesnik, 25, 57–64. jelaska, v. & ogorelec, b. (1983): the upper cretaceous depositional environments of the carbonate platform on the island of brač.– in: babić, lj. & jelaska, v. (eds.): contribution to sedimentology of some carbonate and clastic units of the coastal dinarides. excursion guide–book, 4th ias regional meeting, 99–124, split. jelaska, v. & velić, i. (1971): stratigrafija jure južnog velebita (general stratigraphic review of the jurassic of the southern velebit).– nafta, 22/4–5, 485–495, zagreb. jurkovšek, b., toman, m., ogorelec, b., šribar, l., drobne, k., poljak, m. & šribar, lj. (1996): formacijska geološka karta južnega dela tržaško–komenske planote. kredne in paleogenske karbonatne kamnine, 1:50.000. (geological map of the southern part of the trieste–komen plateau, cretaceous and paleogene carbonate rocks).– inst. geol, geoteh., geofiz., ljubljana, 143 p. jurkovšek, b., kolar-jurkovšek, t. & ogorelec, b. (1997): geology of the divača–kozina motorway section (kras, slovenia).– annales, 11, 161–186, koper. 164 geologia croatica 55/2 165tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... koch, r. (1978): fazies und diagenese eines biostrom– komplexes (oberkreide, jugoslawien).– ergänzungsband erdöl und kohle, compendium 78/79, 41–64, hamburg. koch, r. (1988): mikrofazielle und diagenetische entwicklung kretazischer karbonat-gesteine im jugoslawischen raum.– habilitationsschrift univ. heidelberg, heidelberg, 210 p. koch, r., ogorelec, b. & orehek, s. (1989): microfacies and diagenesis of lower and middle cretaceous carbonate rocks of nw–yugoslavia (slovenia, trnovo area).– facies, 21, 135–170. koch, r., buser, s. & bucur, i.i. (1998): biostratigraphy and facies development of midto late cretaceous strata from the nanos mountain (western slovenia, high karst).– zbl. geol. paläont. i, 11/12, 1195–1215, stuttgart. koch, r., moussavian, e., ogorelec, b., skaberne, d. & bucur, i.i. (2002): development of a lithocodium (syn. bacinella irregularis)–reef-mound – a patch reef within middle aptian lagoonal limestone sequence near nova gorica (sabotin mountain, w. slovenia).– geologija 45/1, 71–90, ljubljana. korbar, t., fuček, l., husinec, a., vlahović, i., oštrić, n., matičec, d. & jelaska, v. (2001): cenomanian carbonate facies and rudists along shallow intraplatform basin margin – the island of cres (adriatic sea, croatia).– facies, 45, 39–58. korbar, t., skelton, p.w., tišljar, j., moro, a., vlahović, i., velić, i. & fuček, l. (2002): middle to upper cenomanian transition: high-energy shoals with recumbent rudists to relatively low-energy environments with elevator rudists in southern istria (gomila, tašalera and fenoliga islet).– in: vlahović, i. & korbar, t. (eds.): 6th international congress on rudists, rovinj, abstracts and excursion guidebook. 111–122, zagreb. krkalo, e., šušnjara, a., šćavničar, b. & gabrić, a. (1995): jurski silicijski sedimenti lemeškog facijesa (malm) u dalmaciji i lici.– in: vlahović, i., velić, i. & šparica, m. (eds.): 1. hrv. geol. kongres, zbornik radova (first croatian geol. congress, proceedings), 1, 321–326, zagreb. lučić, d., benić, j., stanković, d. & miletić, d. (1993): cretaceous/tertiary boundary from the koraljka– 1 off-shore well (sw of zadar, adriatic sea).– geol. croatica, 46/1, 41–61. magaš, n. (1973): osnovna geološka karta sfrj 1:100.000. tumač za list cres l33–113 (basic geologic map of sfry 1:100.000 – geology of the cres sheet).– geološki zavod zagreb (1965), savezni geol. zavod beograd, 42 p. magaš, n. (1980): geološki profil kroz naslage mezozoika i tercijara od rude do blizničkoga brijega (planina kamešnica) u južnoj hrvatskoj (coupe géologique á travers les couches mésosoiques et tertiares de la région ruda–bliznički brijeg (montague de kamešnica) dans la croatie méridionale).– geol. vjesnik, 31, 73–90. mamužić, p. (1975): osnovna geološka karta sfrj 1: 100.000. tumač za list šibenik k33–8 (basic geologic map of sfry 1:100.000 – geology of the šibenik sheet).– inst. geol. istraž. zagreb (1966), savezni geol. zavod beograd, 37 p. mamužić, p. & sokač, b. (1973): osnovna geološka karta sfrj 1:100.000. tumač za listove silba i molat l33– 126 (basic geologic map of sfry 1:100.000 – geology of the silba and molat sheet).– inst. geol. istraž. zagreb (1967), savezni geol. zavod beograd, 45 p. mamužić, p., sokač, b. & velić, i. (1970): osnovna geološka karta sfrj 1:100.000. tumač za list silba l33–126 (basic geologic map of sfry 1:100.000 – geology of the silba sheet).– inst. geol. istraž. zagreb (1963– 1969), savezni geol zavod beograd, 45 p. mamužić, p., polšak, a., grimani, m., šimunić, al., & korolija, b. (1980): detaljni geološki stup kroz naslage cenomana sjeverno od vela luke na otoku korčuli (detailed geological column through cenomanian deposits north of vela luka, island of korčula, dalmatia, southern croatia).– geol. vjesnik, 31, 91–103. mamužić, p., polšak, a., grimani, m., šimunić, al., & korolija, b. (1981): detaljni geološki stup kroz naslage cenomana u zapadnom dijelu otoka hvara (collone stratigraphique détaillée du cenomanien et du turonien dans la partie occidentale de ľile de hvar).– geol. vjesnik, 33, 49–57. mamužić, p., polšak, a., grimani, m. & korolija, b. (1982): detaljni geološki stup kroz naslage cenomana i donjega turona u središnjem dijelu otoka cresa (collone stratigraphique détaillée á travers du cenomanien et du turonien inférieur dans la partie centrale de ľile de cres).– geol. vjesnik, 35, 65–70. mamužić, p., korolija, b., grimani, m. & šimunić, al. (1983): geološki stup kroz naslage krede (raspona gornji cenoman – donji senon) središnjega dijela poluotoka pelješca (collone stratigraphique détaillée á travers les couches cretacées (cénomanien supérieur – sénonien inférieur) dans la partie centrale de la presqu’ile de pelješac).– geol. vjesnik, 36, 73–77. mamužić, p., grimani, m. & šimunić, al. (1984): geološki stup kroz naslage gornjeg turona i donjeg senona kod primoštena u dalmaciji (collone geologique á travers les couches du turonien supérieur – sénonien inférieur près de primošten en dalmatie centrale).– geol. vjesnik, 37, 55–58. marinčić, s. (1981): eocenski fliš jadranskog pojasa (eocene flysch of adriatic area).– geol. vjesnik, 34, 27–38. marinčić, s. & matičec, d. (1989): kolapsne strukture u boksitnim jamama istre (collapse structures in bauxite pits of istria).– geol. vjesnik, 42, 121–131. marinković, r. & ahac, a. (1980): osnovna geološka karta sfrj, 1:100.000, list jajce l33–131 (basic geologic map of sfry 1:100.000 – the jajce sheet).– geoinženjering sarajevo (1975), savezni geol zavod beograd. matičec, d., vlahović, i., velić, i. & tišljar, j. (1996): eocene limestones overlying lower cretaceous deposits of western istria (croatia): did some parts of present istria form land during the cretaceous?– geol. croatica, 49/1, 117–127. matičec, d., vlahović, i., fuček, l., oštrić, n. & velić, i. (1997): stratigraphy and tectonic relationships along the senj–ogulin profile (velika kapela mt., croatia).– geol. croatica, 50/2, 261–268, zagreb. 166 geologia croatica 55/2 167tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... milan, a. (1965): korelacija malma ličke plješevice, senjskog bila i jugozapadnih padina velike kapele (corrélation du malm de la lička plješevica, du senjsko bilo et des versants sw de la velika kapela).– acta geologica, 5, 367–372, zagreb. milan, a. (1969): facijelni odnosi i hidrozojska fauna malma primorskog dijela sjevernog velebita i velike kapele (faziesverhältnisse und hydrozoenfauna des malms im küstenland des nördlichen velebit und velika kapela).– geol. vjesnik, 22, 135–217. mirković, m. & vujisić, p. (1989): osnovna geološka karta sfrj 1:100.000. list žabljak k34–27 (basic geologic map of sfry 1:100.000 – the žabljak sheet).– zavod geol. istraž. crne gore (1980–1986), savezni geol. zavod beograd. mirković, m., kalezić, m. & pajović, m. (1977): osnovna geološka karta sfrj 1:100.000. list bar k34–63 (basic geologic map of sfry 1:100.000 – the bar sheet).– zavod geol. istraž. crne gore (1962–1968), savezni geol. zavod beograd. mirković, m., pajović, m. & kalezić, m. (1979): osnovna geološka karta sfrj 1:100.000. list gacko k34–26 (basic geologic map of sfry 1: 100.000, the gacko sheet).– zavod geol. istraž. crne gore (1967– 1974), savezni geol. zavod beograd. mojičević, m., maksimčev, s. & vrhovčić, j. (1978): osnovna geološka karta sfrj, 1:100.000. list bosanska krupa l33–117 (basic geologic map of sfry 1:100.000 – the bosanska krupa sheet).– inst.geol. istraž. sarajevo (1964–1971), savezni geol. zavod beograd. moro, a. & jelaska, v. (1994): upper cretaceous peritidal deposits of olib and ist islands (adriatic sea, croatia).– geol. croatica, 47/1, 53–66. moro, a., korbar, t., skelton, p.w., velić, i., tišljar, j., vlahović, i., fuček, l., matičec, d. & ćosović, v. (2002): upper santonian rudist-bearing lithosomes formed in the transition from deeper to shallower subtidal environments at cape marlera and učka mountain.– in: vlahović, i. & korbar, t. (eds.): 6th international congress on rudists, rovinj, abstracts and excursion guidebook. 133–139, zagreb. natević, lj. & petrović, v. (1967): osnovna geološka karta sfrj, 1:100.000. list trebinje k34–37 (basic geologic map of sfry 1:100.000 – the trebinje sheet).– geološki zavod sarajevo (1963), savezni geol zavod beograd. nikler, l. (1965): entwicklung der jura in dem nordwestlichen teile der velika kapela.– bull. sci. acad. rsf yugosl. (a), 10/1, 3–4, zagreb. nikler, l. (1969): nerineje titona velike kapele (die nerineen des tithons von velika kapela).– geol. vjesnik, 22, 219–227. nikler, l. (1978): stratigrafski položaj grebenskoga facijesa malma u sjeverozapadnim dinaridima (stratigraphic position of the malmian reef facies in northwestern dinarids).– geol. vjesnik, 30/1, 137–150. ogorelec, b. (1987): sedimentary features of the upper triassic (norian and rhaetian) rocks of the dinaric carbonate platform (sw slovenia).– internat. symp. “evolution of the karstic carbonate platform: relation with other periadriatic carbonate platforms”, abstracts, 45, trieste. ogorelec, b. & dozet, s. (2000): oolitic limestone and dolomite in mesozoic beds in slovenia.– in: vlahović, i. & biondić, r. (eds.): 2. hrvatski geol. kongr. (2nd croatian geological congress), cavtat–dubrovnik, zbornik radova (proceedings), 509–511, zagreb. ogorelec, b., šribar, l. & buser, s. (1976): o litologiji in biostratigrafiji volčanskega apnenca (on lithology and biostratigraphy of volče limestone).– geologija, 19, 125–151, ljubljana. ogorelec, b., orehek, s., buser, s. & pleničar, m. (1987): komen beds – skopo at dutovlje (upper cretaceous).– “evolution of the karstic carbonate platform”, excursion guidebook, 61-66, trieste. ogorelec, b., dolenec, t., cucchi, f., giacomich, r., drobne, k. & pugliese, n. (1995): sedimentological and geochemical characteristics of carbonate rocks from the k/t boundary to lower eocene in the karst area (nw adriatic platform).– in: vlahović, i., velić, i. & šparica, m. (eds.): 1. hrvatski geol. kongr. (1st croatian geological congress), opatija, zbornik radova (proceedings), 2, 415–421, zagreb. ogorelec, b., jurkovšek, b., šatara, d., barić, g., jelen, b. & kapović, b. (1996): potencijalnost karbonatnih kamenin za nastanek ogljikovodikov v zahodni sloveniji (carbonate rocks of west slovenia as potential sources for hydrocarbons).– geologija, 39, 215–237, ljubljana. ogorelec, b., drobne, k., jurkovšek, b., dolenec, t. & toman, m. (2001) paleocene beds of the liburnian formation in čebulovica (slovenia, nw adriatic–dinaric platform) (paleocenske plasti liburnijske formacije v profilu čebulovica (nw jadransko – dinarska platforma)).– geologija 44/1, 15–65, ljubljana. orehek, s. & ogorelec, b. (1979): sedimentološke značilnosti jurskih in krednih karbonatnih kamenin na trnovskem gozdu (sedimentologic features of the jurassic and cretaceous carbonate rocks of trnovski gozd).– geol. vjesnik, 32, 185–192. orehek, s. & ogorelec, b. (1981): korelacija mikrofacialnih in geokemičnih značilnosti jurskih in krednih kamenin južne karbonatne platforme slovenije (correlation of microfacial and geochemical characteristics of jurassic and cretaceous rocks of the southern carbonate platform in slovenia).– zav. geol. i geof. istraž., vestnik, a, 38/39, 171–185, beograd. ottner, f., durn, g., schwaighofer, b. & tišljar, j. (1999): clay minerals in paleosols of cretaceous age in istria, croatia.– chinese science bulletin, 44, suppl. 1, climatic change: paleopedological and soil rocks magnetic approaches, 145–151. pamić, j., gušić, i. & jelaska, v. (1998): geodynamic evolution of the central dinarides.– tectonophysics, 297, 251–268. papeš, j. (1972): osnovna geološka karta sfrj, 1:100.000. list livno k33–11 (basic geologic map of sfry 1: 100.000 – the livno sheet).– geološki zavod sarajevo (1962–1967), savezni geol. zavod beograd. papeš, j. (1985): geologija jugozapadne bosne (geology of the southwestern bosnia).– geol. glasnik, pos. izd. (spec. publ.), 19, 197 p., sarajevo. 166 geologia croatica 55/2 167tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... papeš, j., magaš, n., marinković, r., sikirica, v. & raić, v. (1982): osnovna geološka karta sfrj, 1: 100.000. list sinj k33–10 (basic geologic map of sfry 1:100.000 – the sinj sheet).– geoinženjering sarajevo (1968–1980), inst. geol. istraž. zagreb (1971–1976), savezni geol. zavod beograd. pavlovec, r. (1963): stratigrafski razvoj starejšega paleogena v južnozahodni sloveniji.– razprave sazu, 4. razr., 7, 421–556, ljubljana. pleničar, m. (1973): radiolites from the cretaceous beds of slovenia, part i.– geologija, 16, 187–226, ljubljana. pleničar, m. (1974): radiolites from the cretaceous beds of slovenia, part ii.– geologija, 17, 131–177, ljubljana. pleničar, m. (1975): hipuriti nanosa in tržaško–komenske planote.– razprave 4. razr. sazu, 18, 85–115, ljubljana. pleničar, m. (1977): rudists from the cretaceous beds of slovenia.– geologija, 20, 1–31, ljubljana. pleničar, m. (1979): cretaceous beds in slovenia.– in: drobne, k. (ed.): guidebook of the 16th european micropaleontological colloquium, 37–48, ljubljana. pleničar, m. & jurkovšek, b. (1996): patch reef near senožeče.– razprave 4. razr. sazu, 37/3, 37–83, ljubljana. pleničar, m. & jurkovšek, b. (1997): rudisti iz lipiške formacije v kamnolomu lipica 1.– annales, 11, 115–139, ljubljana. pleničar, m. & jurkovšek, b. (1998): zgornjesantonijski rudisti osrednjega dela tržaško–komenske planote (the upper santonian rudists of the central part of the triest–komen plateau).– razprave iv. razr. sazu, 39/1, 3–53, ljubljana. pleničar, m. & jurkovšek, b. (2000a): rudisti iz cenomanijskih bioherm hrušice in nanosa.– geologija, 42, 69–116, ljubljana. pleničar, m. & jurkovšek, b. (2000b): rudists from the santonian–campanian bioherm near the spring of the lijak brook (sw slovenia).– razprave sazu, 41/1, 51–79, ljubljana. pleničar, m. & jurkovšek, b. (2001): rudisti javornikov.– razprave sazu, 42/1, 103–161, ljubljana. polšak, a. (1965a): stratigrafija jurskih i krednih naslaga srednje istre (stratigrafie des couches jurassiques et crétacées de ľ istrie centrale).– geol. vjesnik, 18/1, 167–184. polšak, a. (1965b): geologija južne istre s osobitim obzirom na biostratigrafiju krednih naslaga (géologie de ľistrie méridionale spécialements par rapport é la biostratigraphie des couches crétacées).– geol. vjesnik, 18/2, 415–510. polšak, a. (1970): osnovna geološka karta sfrj 1: 100.000. tumač za list pula l33–112 (basic geologic map of sfry 1:100.000 – geology of the pula sheet).– inst. geol. istraž. zagreb (1963), savezni geol. zavod beograd, 44 p. polšak, a. (1981): upper cretaceous biolithitic complexes in a subduction zone: examples from the inner dinarides, yugoslavia.– in: toomey, d.f. (ed.): european fossil reef models. sepm spec. publ., 30, 447–472. pugliese, n., drobne, k., barattolo, f., caffau, m., galvani, r., kedves, m., montenegro, m.e., pirini-radrizzani, c., pleničar, m. & turnšek, d. (1995): microand macrofossils from k/t boundary through paleocene in the northern adriatic platform.– in: vlahović, i., velić, i. & šparica, m. (eds.): 1. hrvatski geol. kongr. (1st croatian geological congress), opatija, zbornik radova (proceedings), 2, 505–513, zagreb. radoičić, r. (1966): microfaciès du jurasique des dinarides externes de la yougoslavie.– geologija, 9, 5–378, ljubljana. radoičić, r. & vujisić, t. (1970): korelacija litostratigrafskih stubova boksitonosnog područja zapadne crne gore (corrélation des colonnes litostratigraphiques de la région bauxitifére du monténégro occidentale).– vesnik zav. geol. geofiz. istraž.(a), 165–173, beograd. radovčić, j., tišljar, j. & jelaska, v. (1983): upper cretaceous fish-bearing platy limestones in central dalmatia.– in: babić, lj. & jelaska, v. (eds.): contribution to sedimentology of some carbonate and clastic units the coastal dinarides. excursion guidebook, 4th ias regional meeting, international assoc. of sedimentologists, 79–85, split. riding, r. (1983): cyanoliths (cyanoids): oncoids formed by calcified cyanophytes.– in: peryt, t. (ed.): coated grains. springer verlag, berlin–heidelberg–new york– tokyo, 275–283. sakač, k. (1969): o stratigrafiji, tektonici i boksitima planine grmeč u zapadnoj bosni (on stratigraphy, tectonics and bauxites of the grmeč mountain in western bosnia).– geol. vjesnik, 22, 269–301. sakač, k. & šinkovec, b. (1991): the bauxites of the dinarides.– travaux, icsoba, 20–21, 1–13. sakač, k., jelaska, v. & amšel, v. (1969): the first find of fossils in the cretaceous bauxites of grmeč in western bosnia.– bull. sci., a, 14/7–8, 215–216, zagreb. sakač, k., gušić, i. & šćavničar, b. (1970): age of the clastic and evaporite deposits in environs of drniš (dalmatia).– bull. sci. cons. acad. yugoslav. (a), 15/ 9–10, 312–313, zagreb. sokač, b. (1973): geologija velebita (geology of the velebit mt.).– unpubl. phd thesis, university of zagreb, 151 p. strohmenger, c. & dozet, s. (1990): stratigraphy and geochemistry of jurassic carbonate rocks from suha krajina and mala gora mountain (southern slovenia).– geologija, 33, 315–351, ljubljana. šćavničar, b. & nikler, l. (1976): staklasti tuf u lemeškim naslagama velike kapele (vitric tuff in upper jurassic lemeš-deposits of mt. velika kapela, croatia).– geol. vjesnik, 29, 269–275. šebečić, b., velimirović, z., stoisavljević, m. & trutin, m. (1983): lithostratigraphic survey of the central part of the pelješac peninsula (pelješac formation).– in: babić, lj. & jelaska, v. (eds.): contribution to sedimentology of some carbonate and clastic units the coastal dinarides. excursion guidebook, 4th ias regional meeting, international assoc. of sedimentologists, 63–78, split. 168 geologia croatica 55/2 169tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... šparica, m. (1981): mezozoik banije, korduna i dodirnog područja bosne (geology of the mesozoic areas of kordun, banija and nw bosnia, yugoslavia).– nafta, zagreb, spec. publ., xii+245 p. šribar, lj. (1979): biostratigrafija spodnjekrednih plasti na logaški planoti (biostratigraphy of lower cretaceous beds from the logatec plain).– geologija, 22/2, 277–308, ljubljana. šribar, lj. & pleničar, m. (1990): zgornjekredne cenocone v jugozahodni sloveniji (upper cretaceous assemblage zones in southwestern slovenia).– geologija, 33, 171–205, ljubljana. šribar, lu. (1995): evolucija gornjokredne jadransko– dinarske karbonatne platforme u jugozapadnoj sloveniji.– unpublished m.sc. thesis, university of zagreb, 89 p. šušnjar, m. & bukovac, j. (1978): osnovna geološka karta sfrj 1:100.000, list drvar l33–129 (basic geologic map of sfry 1:100.000 – the drvar sheet).– inst. geol. istraž. zagreb (1969), savezni geol. zavod beograd. šušnjara, a., šćavničar, b. & ivanović, a. (1971): kvarcni sedimenti sjeverozapadnog dijela otoka visa (quartz sediments in the nw part of the island of vis).– geol. vjesnik, 24, 91–101. šušnjara, a., sakač, k., jelen, b. & gabrić, a. (1992): upper permian evaporites and associated rocks of dalmatia and borderline area of lika and bosnia.– geol. croatica, 45, 95–115. tišljar, j. (1976): ranodijagenetska i kasnodijagenetska dolomitizacija i dedolomitizacija u krednim karbonatnim sedimentima zapadne i južne istre (hrvatska, jugoslavija) (early-diagenetic and late-diagenetic dolomitization and dedolomitization in the cretaceous deposits of the western and southern istria, croatia).– geol. vjesnik, 29, 287–321. tišljar, j. (1978a): onkolitni i stromatolitni vapnenci u donjokrednim sedimentima istre (the oncolites and stromatolites in the lower cretaceous deposits of istria, western croatia).– geol. vjesnik, 30/2, 363–382. tišljar, j. (1978b): tidal flat, lagoonal and shallow marine carbonates in the upper jurassic and cretaceous of istria (yugoslavia).– acta geologica, ix/5, 159–194, zagreb. tišljar, j. (1980): fenestralni sklop i vadozne ranodijagenetske tvorevine u litoralnim vapnencima titon–berijasa okolice dubrovnika (the fenestral and vadose early-diagenetic fabric of the tithonian–berriasian peritidal limestones in the dubrovnik area).– krš jugoslavije, 10/3, 77–86, zagreb. tišljar, j. (1983): coated grains facies in the lower cretaceous of the outer dinarides (yugoslavia).– in: peryt, t. (ed.): coated grains. springer–verlag, berlin–heidelberg–new york–tokyo, 566–576. tišljar, j. (1986): postanak crnih valutica i oblutaka (“black pebbles”) u periplimnim vapnencima titona zapadne istre i barema otoka mljeta (origin of the black-pebbles in the peritidal limestones of the western istria (tithonian) and island of mljet (barremian)).– geol. vjesnik, 39, 75–94. tišljar, j. (1992): origin and depositional environments of the evaporite and carbonate complex (upper permian) from the central part of the dinarides (southern croatia and western bosnia).– geol. croatica, 45, 115–127. tišljar, j. (1994): sedimentne stijene.– udžbenik sveučilišta u zagrebu (manualia universitatis studiorum zagrebiensis), školska knjiga, zagreb, 422 p. tišljar, j. (2001): sedimentologija karbonata i evaporita.– institute of geology, zagreb, 375 p. tišljar, j. & velić, i. (1986): ritmična sedimentacija u peritidalnim i lagunskim sedimentima donje krede istre (rhythmical sedimentation in the peritidal and lagoonal deposits of the lower cretaceous in istria).– v skup sedimentologa sfrj, vodič ekskurzije (5th meeting of the yugoslav sedimentologists, excursion guide-book). brijuni, hrvatsko geološko društvo, 1–27, zagreb. tišljar, j. & velić, i. (1987): the kimmeridgian tidal-bar calcarenite facies in western istria (western croatia, yugoslavia).– facies, 17, 277–284. tišljar, j. & velić, i. (1991): carbonate facies and depositional environments of the jurassic and lower cretaceous of the coastal dinarides (croatia).– geol. vjesnik, 44, 215–234. tišljar, j. & velić, i. (1993): upper jurassic (malm) shallow water carbonates of the western gorski kotar: facies and depositional environments (croatia).– geol. croatica, 46/2, 263–279. tišljar, j., đurasek, n., sokač, b. & velić, i. (1981): facijesna korelacija donje krede jadranskog područja (correlation of the lower cretaceous facies in the adriatic coastal and offshore region).– zbornik radova znan. simpozija “naftno-geološka problematika podmorja i priobalnih dijelova jadranskog mora” (symposium on oil-geological problematics of the adriatic coastal and offshore region, proceedings), jazu, 163–171, zagreb. tišljar, j., velić, i., radovčić, j. & crnković, b. (1983a): upper jurassic and cretaceous peritidal, lagoonal, shallow marine and perireefal sediments of istria.– in: babić, lj. & jelaska, v. (eds.): contribution to sedimentology of some carbonate and clastic units of the coastal dinarides. excursion guide-book, 4th ias regional meeting, international assoc. sedimentologists, 13–35, split. tišljar, j., velić, i. & sokač, b. (1983b): flachwasserkarbonate der unterkreide im dinarischen karstgebiet entlang der adriaküste.– zitteliana, 10, 201–206, münchen. tišljar, j., velić, i. & sokač, b. (1989): einflüsse von emersionen auf die flachwasser-karbonatsedimentation im malm (ober jura) des biokovo-gebirges (südkroatien, jugoslawien).– geol. paläont. mitt. innsbruck, 16, 199– 202. tišljar, j., velić, i. & vlahović, i. (1994): facies diversity of the malmian platform carbonates in western croatia as a consequence of synsedimentary tectonics.– géologie méditerranéenne, xxi/3–4, 173–176. tišljar, j., vlahović, i., matičec, d. & velić, i. (1995): platformni facijesi od gornjega titona do gornjeg alba u zapadnoj istri i prijelaz u tempestitne, klinoformne i rudistne biolititne facijese donjega cenomana u južnoj istri (ekskurzija b) (platform facies from the upper tithonian to upper albian in western istria and transition into tempestite, clinoform and rudist biolitite facies of the lower cenomanian in southern istria (excursion b)).– in: vlahović, i. & velić, i. (eds.): 1. hrvatski geološki 168 geologia croatica 55/2 169tišljar, vlahović, velić & sokač: carbonate platform megafacies of the jurassic and cretaceous deposits... kongres, vodič ekskurzija (1st croatian geological congress, excursion guide-book), 67–110, zagreb. tišljar, j., đokić, z. & ženko, t. (1997): influence of the sedimentary environment on the technical properties of the lower cretaceous limestones from the lakovići quarry in istria (croatia).– rgn zbornik, 9, 23–39, zagreb. tišljar, j., vlahović, i., velić, i., matičec, d. & robson, j. (1998): carbonate facies evolution from the late albian to middle cenomanian in southern istria (croatia): influence of synsedimentary tectonics and extensive organic carbonate production.– facies, 38, 137–152. tišljar, j., vlahović, i., skelton, p.w., korbar, t., moro, a., velić, i. & matičec, d. (2002a): upper albian to middle cenomanian facies evolution with extensive rudist production in southern istria (banjole, vinkuran and frašker island).– in: vlahović, i. & korbar, t. (eds.): 6th international congress on rudists, rovinj, abstracts and excursion guidebook. 101–109, zagreb. tišljar, j., vlahović, i., skelton, p.w., moro, a., korbar, t. & velić, i. (2002b): turonian vast production and progradation of rudist shells and debris (valtura quarry, southern istria).– in: vlahović, i. & korbar, t. (eds.): 6th international congress on rudists, rovinj, abstracts and excursion guidebook. 129–132, zagreb. turnšek, d. (1966): zgornjejurska hidrozojska favna iz južne slovenije (upper jurassic hydrozoan fauna from southern slovenia).– razprave sazu, iv, 9/8, 355–428, ljubljana. turnšek, d. (1997): mesozoic corals of slovenia.– zrc sazu, ljubljana, 513 p. turnšek, d., buser, s. & ogorelec, b. (1981): an upper jurassic reef complex from slovenia,yugoslavia.– sepm spec. publ., 30, 361–369. turnšek, d., pleničar, m. & šribar, lj. (1992): lower cretaceous fauna from slovenski vrh near kočevje (south slovenia).– razprave sazu, iv, 33/8, 205–257, ljubljana. velić, i. (1977): jurassic and lower cretaceous assemblagezones in mt. velika kapela, central croatia.– acta geologica, 9/2, 15–37, zagreb. velić, i. & sokač, b. (1978): biostratigraphic analysis of the jurassic and lower cretaceous in the wider region of ogulin, central croatia.– geol. vjesnik, 30/1, 309–337. velić, i. & tišljar, j. (1987): biostratigrafske i sedimentološke značajke donje krede otoka veli brijun i usporedba s odgovarajućim naslagama jugozapadne istre (biostratigraphic and sedimentological characteristics of the lower cretaceous deposits of the veli brijun island and comparison with the corresponding deposits in sw istria, western croatia).– geol. vjesnik, 40, 149–168, zagreb. velić, i. & tišljar, j. (1988): litostratigrafske jedinice u dogeru i malmu zapadne istre (zapadna hrvatska, jugoslavija) (lithostratigraphic units in the dogger and malm of western istria, western croatia).– geol. vjesnik, 41, 25–49. velić, i., tišljar, j. & sokač, b. (1987): the variability of thicknesses of the aptian and albian carbonates as a consequence of changing depositional environments and emersions.– internat. symposium “evolution of the karstic carbonate platform: relation with other periadriatic carbonate platforms”, abstracts, 59–62, trieste. velić, i., tišljar, j. & sokač, b. (1989): the variability of thicknesses of the barremian, aptian and albian carbonates as a consequence of changing depositional environments and emersions in western istra (croatia, yugoslavia).– mem. soc. geol. ital., 40, 209–218. velić, i., vlahović, i. & tišljar, j. (1994): late jurassic lateral and vertical facies distribution: from peritidal and inner carbonate ramps to perireefal and peritidal deposits in se gorski kotar (croatia).– géologie méditerranéenne, 3–4, 177–180. velić, i., matičec, d., vlahović, i. & tišljar, j. (1995): stratigrafski slijed jurskih i donjokrednih karbonata (bat–gornji alb) u zapadnoj istri (ekskurzija a) (stratigraphic succession of the jurassic and lower cretaceous carbonates (bathonian–upper albian) in western istria (excursion a)).– in: vlahović, i. & velić, i. (eds.): 1. hrvatski geološki kongres, vodič ekskurzija (1st croatian geological congress, excursion guide-book), 31–66, zagreb. velić, i., vlahović, i. & matičec, d. (2002a): depositional sequences and palaeogeography of the adriatic carbonate platform.– mem. soc. geol. it., 57, 141–151. velić, i., tišljar, j., vlahović, i., velić, j., koch, g. & matičec, d. (2002b): palaeogeographic variability and depositional environments of the upper jurassic carbonate rocks of velika kapela mt. (gorski kotar area, adriatic carbonate platform, croatia).– geologia croatica, 55/2, 121–138. velić, i., tišljar, j., vlahović, i., matičec, d., korbar, t., moro, a. & ćosović, v. (2002c): geological evolution of istria (nw part of the adriatic carbonate platform, croatia).– in: vlahović, i. & korbar, t. (eds.): sixth international congress on rudists, rovinj 2002, abstracts and excursion guidebook. 83–93, zagreb. veseli, v. (1994): barremian to santonian shallow marine carbonates in the boraja–1 well (adriatic carbonate platform, southern croatia).– géologie méditerranéenne, 3–4, 181–184. veseli, v. (1999): facijesi karbonatnih sedimenata mlađeg mezozoika i paleogena u pučinskim bušotinama sjevernog jadrana (carbonate facies of the late mesozoic and palaeogene in offshore wells from northern adriatic sea).– unpubl. phd thesis, university of zagreb, zagreb, 306 p. veseli, v., tišljar, j., tadej, j. & premec-fuček, v. (1991): lithofacies and biofacies of cretaceous and paleogene carbonate sediments in kate–1 off-shore well (kornati area, adriatic sea, croatia).– in: velić, i. & vlahović, i. (eds.): second internat. symposium on the adriatic carbonate platform, abstracts, 115–116, zagreb. vlahović, i. (1993): facijesi i taložni sustav cenomanskih karbonatnih naslaga područja buzet–savudrija (facies and depositional system of the cenomanian carbonate deposits of the savudrija–buzet area, northern istria).– unpubl. msc thesis, university of zagreb, 118 p. 170 geologia croatica 55/2 vlahović, i. (1999): karbonatni facijesi plitkovodnih taložnih sustava od kimeridža do gornjega alba u zapadnoj istri (carbonate facies of shallow-marine depositional systems from kimmeridgian to late albian in western istria).– unpubl. phd thesis, university of zagreb, 327 p. vlahović, i. & velić, i. (eds.) (1991): some aspects of the shallow water sedimentation on the adriatic carbonate platform (permian to eocene), excursion guide-book.– the second international symposium on the adriatic carbonate platform – relations with adjacent regions, 121 p., zagreb. vlahović, i., tišljar, j. & velić, i. (1994): influence of synsedimentary tectonics and eustatic changes on deposition of the cenomanian platform carbonates in istria (western croatia).– géologie méditerranéenne, 3–4, 189–193. vlahović, i., tišljar, j., velić, i. & matičec, d. (2000): lacuna di importanza regionale corrispodente all’intervallo aptiano superiore – albiano superiore: limite tra la seconda e la terza megasequenza. stop 7: canfanaro/kanfanar.– in: carulli, g.b. (ed.): guida alle escursioni. 80a riunione estiva, trieste, 6–8 settembre 2000, 269–275, società geologica italiana, trieste. vlahović, i., tišljar, j., fuček, l., prtoljan, b., velić, i. & matičec, d. (2002a): the origin and importance of the dolomite–limestone breccia between the lower and upper cretaceous deposits of the adriatic carbonate platform: an example from ćićarija mt. (istria, croatia).– geol. croatica, 55/1, 45–55. vlahović, i., korbar, t., moro, a., velić, i., skelton, p.w., fuček, l. & tišljar, j. (2002b): latest cenomanian to earliest turonian platform drowning and turonian recovery of shallow-water platform deposition in southern istria.– in: vlahović, i. & korbar, t. (eds.): 6th international congress on rudists, rovinj, abstracts and excursion guidebook. 123–127, zagreb. vlahović, i., tišljar, j., velić, i. & matičec, d. (2002c): the karst dinarides are composed of relics of a single mesozoic platform: facts and consequences.– geol. croatica, 55/2, 171–183. vrhovčić, j., vujnović, l. & mojičević, m. (1983): osnovna geološka karta sfrj 1:100.000. list ključ l33– 130 (basic geologic map of sfry 1:100.000 – the ključ sheet).– geoinženjering sarajevo (1969–1978), savezni geol. zavod beograd. vujisić, t. (1972): osnovna geološka karta sfrj 1:100.000. list nikšić k34–38 (basic geologic map of sfry 1: 100.000 – the nikšić sheet).– zavod geol. geofiz. istraž. beograd (1962–1967), savezni geol. zavod beograd. vujnović, l. (1980): osnovna geološka karta sfrj 1: 100.000. list bugojno l33–143 (basic geologic map of sfry 1: 100.000 – the bugojno sheet).– geoinženjering sarajevo (1967–1975), savezni geol. zavod beograd. živaljević, m., đokić, v., & pajović, m. (1971): osnovna geološka karta 1:100.000. list titograd k34–51 (basic geological map 1:100.000, the titograd sheet).– zavod za geološka istraživanja titograd (1962–1967), savezni geološki zavod beograd. mansour.indd diagenesis of upper cretaceous rudist bivalves, abu roash area, egypt: a petrographic study ahmed sadek m. mansour 1. introduction the upper cretaceous was a period when reefs and reef mounds were abundant in many parts of the world (james, 1983). one of the most remarkable features of the cretaceous carbonate platforms in tropical and subtropical environments of the tethyan realm, was the development of facies complexes dominated by rudists, with or without associated corals (masse & philip, 1981; ross & skelton, 1993; gili et al., 1995b). geologia croatica 57/1 55–66 6 figs. zagreb 2004 key words: rudists, diagenesis, silicification, upper cretaceous, egypt. department of geology, faculty of science, alexandria university, 21511 moharm baih, alexandria, egypt; e-mail: ah_sadek@hotmail.com abstract upper cretaceous rudist buildup from the abu roash area, egypt, is characterised by floatstone to rudstone textures. the low diversity of rudist types, the abundant fine-grained carbonate matrix, and the presence of some coral heads suggest that the investigated buildup was developed under warm, relatively quiet, somewhat protected water conditions, in a shallow shelf area or open lagoon. the rudist shells underwent different types of diagenetic alteration (e.g. cementation, neomorphism, partial silicification, and compaction). different types of calcite cements are recorded: (a) early marine micritic and bladed cement, (b) early meteoric isopachous and equant calcite, and (c) late meteoric vug-filling calcite of coarse crystalline texture after partial dissolution of the shells. stabilization of the bimineralic shells took place within a meteoric phreatic milieu, where the aragonitic shell layers were dissolved or recrystallized to more stable diagenetic calcite and the calcitic layers also suffered some recrystallization. silicification of the shell components is the more important diagenetic event. it postdates the early meteoric diagenetic equant calcite cement and occurred before the precipitation of the late meteoric diagenetic vug-filling cement. megaquartz and fibrous chalcedony partially replaced the shells. the silica was probably derived from different sources, pressure-solution of quartz and transformation of clay minerals during later compaction of underlying siliciclastic rocks and/or dissolution of silica-producing organisms such as silica sponge spicules and radiolaria. silicification possibly occurred within a mixing zone environment where meteoric water, which is the carrier of silica, mixed with marine water producing a solution supersaturated with quartz and undersaturated with respect to caco3 minerals. kauffman & johnson (1988) proposed that the rudists evolved to become the primary reef-builders of the cretaceous. in the abu roash area, northern egypt (fig. 1), environmental conditions during the turonian allowed shallow marine benthonic communities with rudists and milleporoid corals as frame builders to flourish (hamza, 1993). the traditional perception of rudists as reef builders has been questioned (gili et al., 1995a), and rudist communities are interpreted as gregarious sediment-dwellers and regarded as biostromes. reefs are particularly susceptible to diagenetic modifications and, because of their relatively welldefined limits, are exceptionally favourable sites for the study of diagenetic processes and sequences (purser & schroeder, 1986). coral and algal reef diagenesis have been studied intensively, meanwhile rudist biostromes have received less attention (e.g., al-aasm & veizer, 1986a, b; enos, 1986; m’rabet et al., 1986; woo et al., 1993; moss & tucker, 1995; steuber, 1999). rudist communities, which crop out in the abu roash area, have been studied by few authors. hamza (1993) studied the rudist–coral mounds at the el hassana dome, abu roash area, from the sedimentological and palaeoecological viewpoints. de castro & sirna (1996) and el-sabbagh & el-hedeny (2003) have undertaken palaeontological studies. the purpose of this study is to demonstrate the different types of diagenetic alteration that affected the rudists in this buildup and to define the sequence of these diagenetic processes. 2. geological setting and stratigraphy the abu roash area represents one of the structural highs that characterize the northern parts of egypt. these are represented by a group of ne–sw trending, plunging synand anticlines, related to the syrian arc system of folds initiated due to the late cretaceous tectonic movements (said, 1962). abd el shafy (1984) mentioned that the abu roash area was slightly subjected to tectonic activity in the form of interrupted pulses, during sedimentation of the turonian rocks, thus causing their uplift. this turonian tectonic phase is considered as an interrupted pulse of the laramid 56 geologia croatica 57/1 57mansour: diagenesis of upper cretaceous rudist bivalves... movements associated with global lowering of sea level and the elevation of numerous areas which are recorded along the southern tethyan margin, as in syria, palestine, libya, tunisia and northern egypt (kerdany & cherif, 1990; m’rabet et al., 1992; said, 1962). furthermore, the upper cretaceous rocks at abu roash area were subjected, at least in localized parts, to the hydrothermal effects of tertiary volcanicity, which resulted in differential silicification and dolomitization of some beds (abd el shafy, 1984; faris & soliman, 1961). moustafa (1988), however, studied the structural setting of the abu roash area in some detail, and recognized a series of half domes, namely el gaa, el hassana and el ghigega, which were a result of the turonian tectonic phase. in the abu roash area, a complete sequence of upper cretaceous strata crops out (fig. 2). the rocks are mainly composed of limestones and dolomites with shales and marly intercalations. topographically, the elevated upper cretaceous rocks are surrounded by younger tertiary rocks in lowland areas. at the el hassana dome, the core of the domal structure is represented by cenomanian clastics (i.e. sandstone and shales), which are overlain by 140 metres of fossiliferous and chalky limestones and marls with occasional dolomite beds of turonian age (faris & soliman, 1961; ghorab & ismail, 1970). the exposed upper cretaceous rock sequence is divided, stratigraphically, into the following series from base to top: sandstone series, rudistae series, limestone series, actaeonella series, flint series, plicatula series and chalk (beadnell, 1902; faris, 1948; said, 1962). the entire rock units beneath the chalk are grouped into only one stratigraphic unit, which is the abu roash formation of norton (1967). in the studied area the actaeonella series, which include the rudist biostrome, is characterized by the presence of some common turonian index fossils including actaeonella (trochactaeon) salomonis, nerinea requieniana and millestroma nicholsoni. the studied rudist shells are collected from the well-developed organic buildup (biostrome) at the el hassana dome. this biostrome crops out in the form of an isolated mound and consists of rudist–coral communities in which rudists of the elevator type (radiolitids) are common. de castro & sirna (1996) stated that the rudist biostrome of the el hassana dome is made up mostly of radiolitids, referred to durania arnaudi. in a more recent study, el-sabbagh & el-hedeny (2003) recorded seven radiolitid species belonging to three genera (durania, lapeirousella and sauvagesia). the rudist shells are present in the form of isolated specimens or small clusters embedded in marly limefig 1 simplified geological and location map of the abu roash area (after said, 1962). 56 geologia croatica 57/1 57mansour: diagenesis of upper cretaceous rudist bivalves... stone beds in an interval about 5 metres thick. the size of the whole shell reaches 20 cm. the rudist shells are associated, in some intervals, with coral heads of hemisphaerical growth forms that may reach 30 cm in size. the rudist–coral dominated beds occur and are exposed on the top of the actaeonella series, flanking the crest of the dome (fig. 2). these limestone beds are underlain by pale yellow to white fine-grained compacted limestones crowded with gastropod shells (mostly actaeonella (trochactaeon) salomonis), rich in miliolid foraminifera and overlain by fossiliferous carbonates composed of sand-size particles. 3. petrography and facies analysis the rudist-dominated mound is, petrographically, composed of floatstones to rudstones where whole rudists and fragments of their shells are, in addition to rounded dark pellets and some sand-sized bioclasts, embedded in a carbonate matrix. the matrix is of finegrained texture and more or less marly in composition. the recorded bioclasts include bivalves (rudists are more common), corals, rare echinoderms and bryozoa, in addition to a few benthic foraminifera. a little microcrystalline calcareous cement is observed in parts, where the amount of micritic matrix decreases, and it cemented the fine bioclasts. the fine-grained matrix is, in parts, neomorphically crystallized to a coarser crystalline texture. the studied turonian rudist shells are mainly those of radiolitids. in general, the radiolitid rudist shells are composed of three layers (skelton, 1974; ross & skelton, 1993), an outer well preserved thick layer composed of fibrous prisms of low-mg calcite and two inner thin aragonitic layers (al-aasm & veizer, 1986a). the inner metastable aragonitic layers are either altered to more stable diagenetic low-mg calcite or are completely dissolved. petrographic studies of the investigated radiolitid rudists reveal that only the outer calcitic layer is preserved, while the inner aragonitic layers were dissolved. the outer calcitic layer is composed of a thick outer cellular layer called the “cellular–prismatic layer” by deschaseaux et al. (1969), and a thin brown inner prismatic layer. the outer cellular layer is characterized by an original hollow structure of honeycomb-like cells (woo et al., 1993; steuber, 1999), and shows a reticulate pattern in thin section. the calcite prisms of the outer layer are cut by dull inclusions, probably representing organic matter remnants, arranged in lines similar to the pattern of growth laminae in modern unaltered bivalve shells (bathurst, 1975; woo et al., 1993; steuber, 1999). the cells are now filled with diagenetic coarse crystalline calcite cement (intraskeletal void-filling spar) and authigenic coarse quartz crystals. in contrast, the body cavities of the shells are either filled with a fine-grained marly carbonate matrix or are partially lined by coarse crystalline calcite cement. in general, rudists were abundant in low-latitude, warm, shallow carbonate-dominated seas (ross & skelton, 1993). hamza (1993) suggested that the fig 2 (a) general sequence of the upper cretaceous rock units in the abu roash area (after said, 1962). (b) rock succession and related microfacies in the studied mound at the el hassana dome. 58 geologia croatica 57/1 59mansour: diagenesis of upper cretaceous rudist bivalves... frequent fine carbonate sediment accumulation, the low content of terrigenous materials, and the enormously thick rudist shells in the rudist–coral buildup in the abu roash area, egypt, indicate development under a warm, arid climate, in an outer shelf area. the low diversity of the studied rudists (very rare species of elevator rudists of broad-conical morphotype are dominant), and their association with some miliolid foraminifera may indicate shallow, relatively quiet water, of somewhat protected areas in the inner shelf or lagoonal settings (cf. skelton et al., 1997; steuber, 2000). however, the occasional association of rudists with some coral heads suggest that depositional environment varied from a shallow inner shelf area to slightly deeper and more open water settings where the corals are more developed (cf. hamza, 1993; ross & skelton, 1993; skelton et al., 1997). alternatively, the rock succession at the studied rudist-dominated mound includes, in addition to the rudist carbonate facies, different fossiliferous finegrained carbonate facies with nerineids, acteonelids and miliolids, which suggest that sedimentation took place in an open lagoon (cf. sanders & pons, 1999). petrographic investigations of the rock succession indicate that the rock microfacies varied vertically (fig. 2). the rudist dominated beds are underlain by white to yellow fine-grained limestones, represented by biopeloidal wackestones and floatstones to packstones rich in actaeonella (trochactaeon) salomonis, peloidal grains, miliolid foraminifera, fine echinoid shell fragments and micritized bioclasts. these microfacies show obvious affinities with a shallow marine, semirestricted setting of low energy, in the inner to middle shelf environments (enos, 1983). in contrast, the rudist-dominated beds are overlain by coarse-grained limestones of sand-sized grains of different fossils, bioclasts, peloids and intraclasts, and are represented by packstone to grainstone microfacies. the variations from wackestone and floatstone at the base of the succession to packstone and grainstone near the top parts and with the upward decreasing of the amount of the fine-grained matrix indicate a shallowing upward trend in the depositional environment. 4. diagenesis the rudist bivalves underwent different types of diagenetic alteration under both marine and meteoric-diagenetic environments. diagenesis of the studied rudists involved variable types of calcite cements, partial silicification of the rudist shells, and neomorphic alteration of the original metastable carbonate components. 4.1. carbonate cementation different calcite cement types are observed within the rudist shells (fig. 3a–d). the cements occlude primary and secondary pore spaces of the shells and each one exhibits its own peculiar texture, origin and timing of formation. cellular cavity-filling calcite the original intraskeletal pores within the thick cellular–prismatic outer layers of the studied rudist shells are filled with more than one cement phase: (a) micritic calcite cement lined the wall of some cells precipitated during an early marine diagenetic stage. the micritic crystals may be recrystallized to microspar during subsequent diagenetic stages. (b) thin clear isopachous calcite crystals fringe at one side of some skeletal cell walls (fig. 3a, b). this isopachous calcite represents an early meteoric diagenetic cement and its bladed isopachous rim geometry indicates a freshwater phreatic origin (cf. longman, 1980). (c) equant calcite cement with crystals of clear subhedral, coarse crystalline texture completely filled the cells (fig. 3a, b). this coarse equant calcite cement also occludes the intraskeletal pores of the coral heads. the fabrics of this calcite cement suggest that it formed from phreaticmeteoric water after subaerial exposure of the turonian rocks. in later stages, this calcite cement is partially replaced by authigenic silica. irregular vug-filling calcite few small vugs, after partial dissolution of the shells by freshwater, were later filled by coarse crystalline meteoric calcite cement (fig. 3c). these irregular pores cut the skeletal cells, which are filled by both the equant calcite cement of the early meteoric-diagenetic phase and by the silica pore-filling. this indicates that formation of this cement postdates both precipitation of the early meteoric equant cement and the silicification of the shells. body cavity-filling calcite the large body cavities of the rudist shells are almost filled by fine-grained carbonate sediments with fine shell fragments, benthonic foraminifera and peloidal grains. in some cases, the position of the shells allowed the lining and partial infilling of the internal cavities by coarse crystalline calcite. these calcite crystals have two fabrics: (a) columnar calcite (fig. 3d) of inclusionrich, very coarse, elongate crystals where their long axes are normal to the inner prismatic shell layer, and (b) equant calcite of coarse crystalline texture. 4.2. silicification one of the most important diagenetic features observed in the studied rudist shells is the partial silicification of some shells. this also affected the skeleton of the coral heads. the silicification process affects the structural layers of the whole shells and also some fine rudist shell debris embedded in the matrix, while the fine-grained matrix exhibits no replacement by silica. the selective silicification of the rudist shells may be attributed to 58 geologia croatica 57/1 59mansour: diagenesis of upper cretaceous rudist bivalves... organic matter acting in some way as a catalyst, which may increase carbonate solubility (hesse, 1987). jacka (1974) suggested that organic decomposition products create a special microenvironment conducive to silica-replacement. the reported authigenic silica is found either as pore-filling in the cellular shell structure or as partial replacement of the shells (fig. 4a–f). it is precipitated in the form of equigranular megaquartz and fibrous quartz as spherulitic chalcedony. quartz cavity-filling the silica is precipitated as crystals of megaquartz, infilling intraskeletal pores of the cellular–prismatic outer layer of some shells (fig. 4a). the quartz is of clear, equant, coarse to medium crystalline fabric. some of the crystals possess wavy extension and others are cracked. the contact of the quartz crystals with the boundary of the cell is sharp and these boundaries are not dissolved or replaced by the silica and the original shell microstructure is preserved. this indicates that the quartz crystals were precipitated as cavity-filling cement after stabilization of the wall boundaries. the presence of relics of diagenetic equant calcite cements inside the quartz crystals suggest that silicification occured after calcite cementation of cells in the shell where quartz replaced the former equant calcite cements during or after their dissolution. spherulitic chalcedony in this form, crystals of chalcedony partially replaced the structural layers of the rudist shells and the coral skeleton (fig. 4b–e). the crystals are of finely fibrous fabric with wavy extension and form small spherulitic shapes. the replacement of the rudist shells by chalcedony is mostly destructive to the shell fabric. the thin inner prismatic layers were highly subjected to silicification and partial replaced by chalcedony and their microstructure was obscured (fig. 5c). also, the cells of the outer cellular–prismatic layers that were filled with equant calcite crystals, are partially replaced a b c d 0.3 mm 0.1 mm 0.3 mm0.1 mm fig. 3 (a) photomicrograph showing the microstructure of the outer cellular–prismatic layer of a radiolitid shell. the intraskeletal pores are filled with two phases of calcite cements. crossed nicols. (b) enlargement of (a). note the two phases of cements, isopachous rim (arrow) and coarse equant calcite. crossed nicols. (c) irregular vug is filled with coarse crystalline calcite (c). note that the void cut the cells, which are filled with authigenic silica cement – s. plane light. (d) columnar calcite crystals line the internal body cavity of the shell. note that the elongated crystals are normal to the prismatic layer (arrow). crossed nicols. s c 60 geologia croatica 57/1 61mansour: diagenesis of upper cretaceous rudist bivalves... by chalcedony and the boundaries of these cells are mostly obliterated. relics of the original calcitic components are found between the chalcedony crystals. 4.2.1. sources of silica silica in the turonian rocks of the studied area includes the silicification products of the rudists and the thin bands of chert interbedded with the carbonate sediments. in general, the sources of silica are unequivocal. the biogenic source of silica is considered as the common one by many workers (e.g. jacka, 1974; knauth, 1979; lawrence, 1994; gimenez-montsant et al., 1999), where the silica can be derived from dissolution of silica-producing organisms such as siliceous sponge spicules, radiolaria and diatoms. also, the silica can be derived from a silica-rich solution generated by pressure-solution of sand and silt quartz grains or feldspar (hesse, 1987; houseknecht, 1988), by the transformation of montmorillonite to illite or mica (keene & kastner, 1974; lawrence, 1994), or from rapid cooling and a change in the ph of silica-supersaturated hot geothermal water (jones et al., 1997). keheila & el-ayyat (1992) considered volcanic ash and tuffs to be a source of silica for chert nodules in the drunka fm. along the nile river valley. faris & soliman (1961) and abd el shafy (1984) recorded some metasomatic alteration in parts of the upper cretaceous and eocene rocks in the abu roash area. they suggested that these rocks were subjected, at least in some parts, to silicification and to iron and manganese mineralization by the tertiary ascending hydrothermal solutions. from the geological setting of the studied el hassana dome area, the turonian beds were affected by late cretaceous tectonic movements causing the folding of these beds, including the interbedded chert bands. also, no volcanogenic materials and other effects of hydrothermal solution are observed. it can be suggested that the formation of these chert bands and also the silicification of some turonian rocks preceded the tectonic movements. therefore, the volcanic origin of silica required for silicification of the rudist shells and also formation of the interbedded chert bands can not be suggested. it can be considered that the silica required for silicification of the rudist shells may be derived from more than one source as: biogenic silica from the host and surrounding late cretaceous carbonate rocks, and/or pressure-solution of quartz and feldspar and the transformation of clay minerals during the compaction of the underlying cenomanian and pre-cretaceous sandstone and mudstone rocks. this silica was redistributed and migrated from the host or surrounding rocks to the site of diagenesis, and then replaced the shells. 4.2.2. mechanism of silicification textural relationships of silica-replacement within the rudist shells indicates that silicification postdates the deposition of the rocks and occurred after the precipitation of the early diagenetic meteoric calcite cement in the intraskeletal cavities of the cellular shell microstructure (fig. 4e). textural evidence shows that the authigenic quartz (megaquartz and chalcedony) were formed by volume-by-volume replacement of the original carbonate minerals of the shells or calcite cavity filling, where carbonate dissolution rarely occurred immediately adjacent to the silicified parts. this indicates that calcite dissolution is linked to silica precipitation during the silicification process and they may have occurred simultaneously. silica can not be precipitated within a normal marine environment, but it precipitates in certain environments that controlled the prevailing physico–chemical conditions. it began to precipitate with the reduction of the ph of the waters or by the mixing of marine and meteoric waters (knauth, 1979; maliva & siever, 1988). according to maliva & siever (1988), silicification requires a sufficient degree of local supersaturation with respect to authigenic silica and suitable conditions for nucleation of the initial crystals. the chertification of the lower eocene drunka formation (mc bride et al., 1999) and thebes limestones (abd el-hameed et al., 1997) in some areas in egypt, was attributed to dominantly meteoric fluids, possibly a time when meteoric water was flushing marine pore water. thiry & ribet (1999) proposed that silicification of limestones is considered as a groundwater process and occurs within the groundwater or in the vicinity of the water table or even above the water table after the uplift of the rocks. they suggested that the silica introduced by high flow rates of groundwater through the interstices, where the calcite–silica replacement takes place through diffusion along very thin intergranular water films. knauth (1979) proposed that silica can replace carbonate in the mixing zone when silica-rich meteoric water mixes with marine water producing waters highly supersaturated with respect to quartz and undersaturated with respect to calcite and aragonite. one of the characteristic features associated with the silicification process is the presence of a few disseminated euhedral dolomite rhombs inside some rudist shells and coral heads and also in the finegrained matrix (fig. 4f). these dolomite rhombs exist as individual crystals and mostly have dissolved cores with dark rims. dolomite inclusions in the siliceous rocks are recorded and described elsewhere by many authors. kastner et al. (1977) attributed the origin of dolomite rhombs in chert to the release of magnesium during the transformation of opal-ct to quartz. jacka (1974) attributed the formation of microdolomite in silicified carbonate rocks to the silicification process where, to some degree, exsolution of dolomite and replacement of high-mg calcite by chalcedony occurred concurrently. according to the model of silicification in a mixing-zone environment proposed by knauth 60 geologia croatica 57/1 61mansour: diagenesis of upper cretaceous rudist bivalves... a 0.3 mm 0.3 mm b c d e f 0.3 mm 0.3 mm 0.3 mm 0.1 mm fig. 4 photomicrographs showing partial silicification of the rudist shells. (a) equant megaquartz crystals fill the pores of the cellular–prismatic layer after their replacement by equant calcite cement. note the preservation of the original microstructure of the cell walls. crossed nicols. (b) high silicification of the cellular–prismatic layer and the replacement of calcitic components by chalcedony. crossed nicols. (c) similar as (b) – the original cellular microstructure has begun to be destroyed by the presence of remnant organic materials. plane light. (d) partial silicification of the skeleton of a coral head. note the destruction of the original microstructure after its replacement by chalcedony. relics of equant calcite cement are still present. crossed nicols. (e) start of silicification of the shells after the filling of the intraskeletal pores of the cellular–prismatic layer by coarse equant calcite cement. crossed nicols. (f) a few dolomite rhombs associated with the silicified shell after its replacement by chalcedony. plane light. 62 geologia croatica 57/1 63mansour: diagenesis of upper cretaceous rudist bivalves... (1979), these conditions can allow the concurrent precipitation of dolomite during silicification. hesse (1987) suggested that microdolomite formation was independent of silicification and that it is produced during the stabilization of high-mg calcite components to low-mg calcite. gimenez-montsant et al. (1999) related the presence of dolomite crystals within the cherts to early diagenetic interaction between the silica-rich fluids and the host sediment before chert formation. the occurrence of the dolomite rhombs, in both the studied carbonate matrix and in the silicified parts of the rudist shells and corals suggests that the formation of the dolomite is related to the silicification process, but the magnesium originated and was released from the calcareous components during their stabilization and dissolution. accordingly, it can be proposed that the silicification process took place in the mixing-zone environment and was associated with minor late diagenetic dolomitization. on the other hand, the presence of authigenic quartz in the silicified rudist shells in two forms, equant megaquartz and fibrous chalcedonic quartz, is highly controlled by the rate of nucleation and crystallization, which in turn is mostly dependent on the degree of saturation (folk & pittman, 1971). with high silica concentrations and rapid precipitation, chalcedony is formed, while equant megaquartz usually forms at slower rates of precipitation from solutions having low degree of silica supersaturation. thus, it can be proposed that the silicification of the rudist shells might take place either in more than one stage, and each stage was characterized by different conditions of the degree of saturation and rate of crystallization, or the two quartz-phases were precipitated concurrently with the presence of micro-variability in the concentration of dissolved silica in the fluids. a b dc 0.3 mm 0.3 mm 0.1 mm0.1 mm fig. 5 (a) photomicrograph of the outer cellular–prismatic layer of a radiolitid showing the recrystallization of the cell walls to coarse crystallized calcite. note the presence of the dark relics of the original microstructure (arrow). the intraskeletal pores are filled with coarse equant quartz crystals. crossed nicols. (b) radiolitid shell, showing the thick outer cellular–prismatic and the thin inner prismatic layers. note the partial preservation of their microstructure. plane light. (c) radiolitid shell showing partial silicification of the prismatic layer (arrow), with complete obliteration of the original microstructure in the silicified parts. plane light. (d) break up of a cell wall in the cellular layer due to early mechanical compaction. the cells are filled with equant calcite cement. crossed nicols. 62 geologia croatica 57/1 63mansour: diagenesis of upper cretaceous rudist bivalves... 4.3. neomorphism of the shell layers the bimineralic and polylayered rudist shells underwent diagenetic alteration during the meteoric diagenetic stages. the cells wall of the outer thick cellular– prismatic calcite layers have been highly recrystallized to coarse crystalline, more stable diagenetic low mg-calcite, with the presence of micritic relics (fig. 5a). however, the cell walls preserved their original microstructures and identities. also, the thin prismatic calcite layer probably suffered some recrystallization, but their original microstructure is mostly preserved (fig. 5b). in contrast, the original aragonitic inner thin layers of crossed-lamellar microstructure are not observed in the studied rudist shells. they have been either dissolved and subsequently infilled by equant calcite cement or by internal sediments, or were neomorphically transformed to the more stable low-mg calcite, without preservation of the original microstructure during periods of exposure to meteoric waters. similar diagenetic alterations of rudist shells are reported by al-aasm & veizer (1986a) and woo et al. (1993). the primary microstructures of the layers have been highly destroyed when the layers were subjected to silicification and replaced by fibrous chalcedony (fig. 5c). 4.4. compaction the rudist shells were subjected to fragmentation, after settling in the shallow marine conditions, by the effect of current and waves resulting in the reduction of some shells to coarse and fine debris, and breaking up of the cell walls of the cellular–prismatic layer of some shells before the introducing of the equant meteoric calcite cement (fig. 5d). also, the rudist shells were subsequently subjected to compaction in shallow burial conditions, resulting in some mechanical compaction fabrics, including breaking up of some shells, orientation of some rudist shell fragments, and cracking of some quartz crystals and their exhibition of wavy extinction. 5. paragenetic sequence petrographic observations of the studied turonian rudists in the abu roash area show that the shells were subjected to different diagenetic alteration during marine, mixed marine–meteoric, and meteoric diagenesis and also during shallow burial diagenesis. each diagenetic stage is characterized by certain diagenetic processes (fig. 6). a paragenetic sequence reveals the different diagenetic events that can be proposed as follows: (1) early marine diagenesis: in this stage, a little micritic calcite cement was precipitated in the pores of the cellular layer and the body cavities of some shells and formed in submarine conditions. subsequent meteoric alteration may affect this cement where it was recrystallized to microspar. some bladed high mgcalcite crystals were probably formed in this stage and precipitated as an isopachous rim, lining some pores of the cellular layer. fragmentation and break down of cells walls of some shells took place in this stage. (2) early meteoric diagenesis: with the subaerial exposure of the sequence, the rocks were subjected to meteoric water diagenesis, including precipitation of two types of calcite cement that occluded the intraskeletal pores of the cellular layers. the first type is the isopachous calcite rim, which was followed by precipitation of equant calcite cement as a complete fig. 6 chart of the paragenetic sequence of the studied rudist shells. straight lines indicate clearly observed processes; dash lines indicate minor processes. 64 geologia croatica 57/1 65mansour: diagenesis of upper cretaceous rudist bivalves... infilling of the intraskeletal pores. also in this stage the columnar calcite crystals, which lined the large body cavity of the shells, were precipitated. stabilization and recrystallization of the shell components began. (3) mixing zone diagenesis: partial silicification of the rudist shells and coral heads may have occurred in the mixing zone environment where meteoric water, which is the carrier of silica, mixed with marine water producing a solution of low ph, undersaturated with respect to caco3 minerals but supersaturated with respect to quartz. this solution allowed the partial dissolution of both the shell components and the early meteoric equant calcite cement and the precipitation of authigenic silica. the presence of some disseminated euhedral dolomite rhombs within the silicified rudist shells and the corals and also in the matrix may support the idea of silicification in a mixing zone environment. from petrographic observations, silicification of the shells postdates the precipitation of the early meteoric cements and preceded the precipitation of the late meteoric vug-filling calcite cement. (4) late meteoric diagenesis: with the re-exposure of the beds to a freshwater lens, a few small irregular vugs were formed, cutting the shell components and were infilled by coarse crystalline calcite. this pore-filling cement postdated the formation of early meteoric intraskeletal equant calcite cement and also the silicification of the shells. stabilization and recrystallization of the shell components probably occurred during this stage. (5) shallow burial diagenesis: represented by slight mechanical compaction resulting in the breakage of some shells, cracking of quartz crystals, and also recrystallization of the shell components. 6. conclusions petrographic study of the rudist shells of the upper cretaceous rudist buildup at the el hassana dome, abu roash area revealed that the shells underwent different diagenetic modifications in variable diagenetic environments (marine, meteoric phreatic and mixing zones and also shallow burial setting). there were three major diagenetic stages that the rudist shells have passed through. (1) early submarine diagenetic stage, involving precipitation of a few micritic and bladed calcite cements and break down of some cell walls of the shells. (2) meteoric and mixing zones diagenetic stage during the subaerial exposure of the beds. it involved the precipitation of an early meteoric isopachous calcite rim followed by precipitation of equant and columnar calcite cements. partial silicification of the rudist shells postdated the early meteoric calcite cements and occurred within a mixing zone environment where meteoric water, which is the carrier of silica, mixed with marine water producing a solution which allowed the partial dissolution of both the shell components and the early meteoric calcite cements, and the precipitation of authigenic silica. the silica is probably derived from pressure-solution of quartz and transformation of clay minerals during compaction of the underlying siliciclastic rocks and/or dissolution of silica-producing organisms. in later times, late meteoric vug-filling calcite cement was precipitated. stabilization and recrystallization of the shell components probably occurred during this stage, where the aragonitic shell layers were dissolved or recrystallized to more stable diagenetic calcite and also the calcitic layers suffered some recrystallization. (3) shallow burial diagenetic stage, involving mechanical compaction which resulted in the break up of some shells, cracking of some quartz crystals, and also the recrystallization of the shell components. 7. references abd elshafy, e (1984): on the minor structures of abu roash area, west of cairo, northern egypt.– bull. fac. sci. zagazig univ., 6, 3–10. abd el-hameed, a.t., abdel-wahab, a.a., elshishtawy, a. & abu shama, a.m. (1997): petrogenesis of some lower eocene siliceous rocks from egypt.– egyptian mineralogist, 9, 215–250. al-aasm, i. & veizer, j. (1986a): diagenetic stabilization of aragonite and low-mg calcite, i. trace elements in rudists.– j. sediment. petrol., 56, 138–152. al-aasm, i. & veizer, j. (1986b): diagenetic stabilization of aragonite and low-mg calcite, ii. stable isotopes in rudists.– j. sediment. petrol., 56, 763–770. bathurst, r.c. (1975): carbonate sediments and their diagenesis.– 2nd ed., elsevier, amsterdam, 658p. beadnell, h.j.l. (1902): the cretaceous region of abu roash near the pyramids of giza.– egypt. surv. dept., cairo, 48p. de castro, p. & sirna, g. (1996): the durania arnaudi biostrome of el-hassana, abu roash area (egypt).– geologica romana, 32, 69–91. deschaseaux, c., coogan, a. & cox, l. (1969): systematic descriptions; hippuritoida–hippuritacea.– in: cox, l.r., newell, n.d., boyd, d.w., branson, c.c., casey, r., chavan, a., coogan, a.h., dechaseaux, c., fleming, c.a., haas, f., hertlein, l.g., kauffman, e.g., keen, a.m., larocque, a., mcalester, a.l., moore, r.c., nuttall, c.p., perkins, b.f., puri, h.s., smith, l.a., soot-ryen, t., stenzel, h.b., trueman, e.r., turner, r.d. & weir, j. (eds.): treatise on inverte64 geologia croatica 57/1 65mansour: diagenesis of upper cretaceous rudist bivalves... brate paleontology, part n, 3, mollusca 6, bivalvia. geological society of america and university of kansas press, n749–n817. el-sabbagh, a.m. & el-hedeny, m.m. (2003): upper turonian radiolitidae (rudist bivalves) from the actaeonella series, el-hassana dome, abu roash, egypt.– egyptian j. paleontology (in press). enos, p. (1983): shelf environment.– in: scholle, p.a., bebout, d.g. & moore, c.h. (eds.): carbonate depositional environments. amer. assoc. petrol. geol. mem., 33, 267–296. enos, p. (1986): diagenesis of mid-cretaceous rudist reefs, valles platfom, mexico.– in: schroeder, j.h. & purser, b.h. (eds.): reef diagenesis. springer verlag, new york, 160–185. faris, m.i. (1948): contribution to the stratigraphy of abu rauwash and the history of the upper cretaceous in egypt.– bull. fac. sc. cairo univ., 27, 221–239. faris, m.i. & soliman, s.m. (1961): petrology of the dolomite rocks of abu roash and its consideration to possible petroleum reservoirs in other parts of egypt.– third arab petrol. congr., alexandria, 1–30. folk, r.l. & pittman, j.s. (1971): length-slow chalcedony: a new testament for vanished evaporites.– j. sediment. petrol., 41, 1045–1058. ghorab, m.a. & ismail, m.m. (1970): microfacies of the abu roash surface sections.– bull. fac. sc. alexandria univ., 9, 331–363. gili, e., masse, j.p. & skelton, p.w. (1995a): rudists as gregarious sediment-dwellers, not reef-builders, on cretaceous carbonate platforms.– palaeogeogr. palaeoclimatol. palaeoecol., 118, 245–267. gili, e., skelton, p.w., vicens, e. & obrador, a. (1995b): corals to rudists – an environmentally induced assemblage succession.– palaeogeogr. palaeoclimatol. palaeoecol., 119, 127–136. gimenez-montsant, j., calvet, f. & tucker, m.e. (1999): silica diagenesis in eocene shallow-water platform carbonates, southern pyrenees.– sedimentology, 46, 969–984. hamza, f.h. (1993): upper cretaceous rudist–coral buildups associated with tectonic doming in the abu roash area, egypt.– n. jb. geol. paleont. mh., 2, 75–87. hesse, r. (1987): selective and reversible carbonate–silica replacements in lower cretaceous carbonate-bearing turbidites of the eastern alps.– sedimentology, 34, 1055–1077. houseknecht, d.w. (1988): intergranular pressure solution in four quartzose sandstones.– j. sediment. petrol., 58, 228–246. jacka, a.d. (1974): replacement of fossils by length-slow chalcedony and associated dolomitization.– j. sediment. petrol., 44, 421–427. james, n.p. (1983): reef environment.– in: scholle, p.a., bebout, d.g. & moore, c.h. (eds.): carbonate depositional environments.– amer. assoc. petrol. geol. mem., 33, 345–462. jones, b., rosen, m. & renaut, r.w. (1997): silicacemented beachrock from lake taupo, north island, new zealand.– j. sediment. research, 67, 805-814. kastner, m., keene, j.b. & gieskes, j.m. (1977): diagenesis of siliceous oozes. i. chemical controls on the rate of opal-a to opal-ct transformation – an experimental study.– geochim. cosmochim. acta, 41, 1041–1059. kauffman, e.g. & johnson, c. (1988): the morphological and ecological evolution of middle and upper cretaceous reef-building rudists.– palaios, 3, 194–216. keene, j.b. & kastner, m. (1974): clays and formation of deep-sea chert.– nature, 249, 754–755. keheila, e.a. & el-ayyat, a.m. (1992): silicification and dolomitization of the lower eocene carbonates in the eastern desert between sohag and qena, egypt.– j. afr. earth. sci., 14, 341–349. kerdany, m. & cherif, o.h. (1990): mesozoic.– in: said, r. (ed.): the geology of egypt. balkema publ., brookfield, 407–438. knauth, l.p. (1979): a model for the origin of chert in limestone.– geology, 7, 274–277. longman, m.w. (1980): carbonate diagenesis textures from near surface diagenetic environments.– amer. assoc. petrol. geol. bull., 64, 461–487. lawrence, m.j.f. (1994): conceptual model for early diagenetic chert and dolomite, amuri limestone group, north-eastern south island, new zealand.– sedimentology, 41, 479–498. maliva, r.g. & siever, r. (1988): mechanism and controls of silicification of fossils in limestones.– j. geology, 96, 387–398. masse, j.p. & philip, j. (1981): cretaceous coral–rudistid buildups of france.– in: toomey, d.f. (ed.): european fossil reef models. soc. econ. paleont. mineral. spec. publ. 30, 399–426. mc bride, e.f., abdel-wahab, a. & el-younsy, a.r.m. (1999): origin of spheroidal chert nodules, drunka formation (lower eocene), egypt.– sedimentology, 46, 733–755. moss, s. & tucker, m.e. (1995): diagenesis of barremian–aptian platform carbonates (the urgonian limestone formation of se france): near-surface and shallowburial diagenesis.– sedimentology, 42, 853–874. moustafa, a.r. (1988): wrench tectonics in the north western desert of egypt (abu roash area, southwest of cairo).– mid. east research cent., ain shams univ., earth sc. ser., egypt, 2, 1–16. m’rabet, a., negra, m.h., purser, b.h., sassi, s. & benayed, n. (1986): micrite diagenesis in senonian rudist build-ups in central tunisia.– in: schroeder, j.h. & purser, b.h. (eds.): reef diagenesis. new york (springer), 210–223. m’rabet, a., almaleh, a.k., chellai, e.h., sebta, a.m., icame, n., mouty, m. & razgallah, s. (1992): cretaceous global events and changes of the southern tethyan margin: evidence from the sedimentary record in syria, libya, tunisia and morocco.– 1st intern. conf. geol. arab world, cairo, abstracts, 15. 66 geologia croatica 57/1 norton, p. (1967): rock stratigraphic nomenclature of the western desert.– pan american oil co., u.a.r., 18 p. purser, b.h. & schroeder, j.h. (1986): the diagenesis of reefs: a brief review of our present understanding.– in: schroeder, j.h. & purser, b.h. (eds.): reef diagenesis. springer verlag, new york, 424–446. ross, d.j. & skelton, p.v. (1993): rudist formations of the cretaceous: a palaeoecological, sedimentological and stratigraphic review.– in: wright, p. (ed.): sedimentology review, 1, blackwell, london, 73–91. said, r. (1962): the geology of egypt.– elsevier, amsterdam, 377 p. sanders, d. & pons, j.m. (1999): rudist formations in mixed siliciclastic–carbonate depositional environments, upper cretaceous, austria: stratigraphy, sedimentology, and models of development.– palaeogeogr. palaeoclimat. palaeoecol., 148, 249–284. skelton, p.w. (1974): aragonite shell structures in the rudist biradiolites and some palaeobiological inferences.– géologie méditerranéenne, 1, 63–74. skelton, p.w., gili, e., roson, b.r. & valldeperas, f.x. (1997): corals and rudists in the late cretaceous: a critique of the hypothesis of competitive replacement.– bol. r. soc. esp. hist. nat. (sect. geol.), 92, 225–239. steuber, t. (1999): isotopic and chemical intra-shell variations in low-mg calcite of rudist bivalves (mollusca– hippuritacea): disequilibrium fractionations and late cretaceous seasonality.– int. j. earth sciences, 88, 551–570. steuber, t. (2000): skeletal growth rates of upper cretaceous rudist bivalves: implications for carbonate production and organism–environment feedbacks.– in: insalco, e. et al. (eds.): carbonate platform systems: components and interactions. geol. soc. london, spec. publ., 178, 21–32. thiry, m. & ribet, i. (1999): groundwater silicification in paris basin limestones: fabrics, mechanisms, and modelling.– j. sediment. research, 69, 171–183. woo, k.s., anderson, t.f. & sandberg, p.a. (1993): diagenesis of skeletal and nonskeletal components of mid-cretaceous limestones.– j. sediment. petrol., 63, 18–32. manuscript received january 10, 2003. revised manuscript accepted may 04, 2004. adamcova et al.indd problems of hydraulic conductivity estimation in clayey karst soils renata adamcova1, franz ottner2, goran durn3, sabine greifeneder2, ivan dananaj4, maria dubikova5, rastislav skalsky6, slobodan miko7 and sanja kapelj7 1. introduction karren fields are a typical karst phenomenon in the erosion zones in karst areas, where the uncovered fissured carbonate rock enables very rapid infiltration of surface water, with all pollutants included. groundwater vulnerability is therefore extremely high. elsewhere, there are places continuously covered with soil, which seem to function as natural pollution barriers. a considerable thickness of the soil cover can be found in depressions or in other accumulation zones. the degree of karst groundwater protection by soils depends not only on their thickness, but also on both their hydraulic conductivity and retention properties. between 2000–2003, soils from selected karst terrains in slovakia, croatia and austria (fig. 1) were studied within one slovakian and three international interdisciplinary research projects. this paper summarizes one part of the results, dealing only with the hydraulic conductivity of fine-grained karst soils. it can be concluded that: – wide intervals of hydraulic conductivity were measured by different methods in selected soil types; – hydraulic conductivity assessment methods based solely on the grain-size distribution in the fine-grained soils are unsuitable; – factors influencing the hydraulic conductivity are complex. 2. study areas selected karst areas were chosen for investigation in all three countries. the brezovske karpaty mts. (the small geologia croatica 58/2 195–203 10 figs. 2 tabs. zagreb 2005 key words: karst soils, hydraulic conductivity, triaxial permeameter, consolidometer, guelp permeameter, grain size. 1 comenius university in bratislava, faculty of natural sciences, mlynska dolina, 84215 bratislava 4, slovak republic; e-mail: adamcova@fns.uniba.sk 2 university of natural resources and applied life sciences vienna, institute of applied geology, peter-jordan-strasse 70, a-1190 vienna, austria; e-mail: ottner@mail.boku.ac.at 3 e-mail: gdurn@rgn.hr 4 state geologic survey of slovak republic, mlynska dolina 1, 81704 bratislava 1, slovak republic; e-mail: dananaj@fns.uniba.sk 5 university of new south wales, school of materials science & engineering, 2052 sydney, australia; e-mail: dubikova@materials.unsw.edu.au 6 soil science and conservation research institute, gagarinova 10, 82713 bratislava 2, slovak republic; e-mail: skalsky@vupu.sk 7 croatian geological survey, sachsova 2, 10000 zagreb, croatia; e-mail: smiko@hgi-cgs.hr, sanja.kapelj@zg.t-com.hr abstract even in karst areas, considerably thick soils can be found in accumulation zones. here, the degree of groundwater vulnerability depends not only on the thickness, but also on the hydraulic conductivity and retention properties of the soil cover. the hydraulic conductivity of fine-grained karst soils from slovakia, croatia and austria was studied within several international research projects, by the application of four different test methods. results are discussed from different points of view. triaxial tests yielded a very broad interval between the maximum and minimum hydraulic conductivity (from 5.83x10-7 m.s-1 to 3.50x10-11 m.s-1), therefore the mean value cannot be used in any calculations. the consolidometer method gave lower values in general, between 9.40x10-10 m.s-1 to 3.59x10-8 m.s-1. however, this method overestimates the soil “impermeability”. estimates based on grain size are unsuitable, as fine-grained soils did not fulfil the random conditions of known formula. finally, the “in situ” hydraulic conductivity was measured using a guelph permeameter. as expected, “in situ” tests showed 100 to 1000-times higher kf than the laboratory tests. this method best reflects the real conditions. therefore, only this type of data should be considered in any environmental modelling. in a soil profile, hydraulic conductivity depends on the mineral composition, depth, secondary compaction, etc. the degree and duration of saturation with water is very important for young soils containing smectite. their hydraulic conductivity might be very low when saturated for long time, but also very high, when open desiccation cracks occur. a very slight trend was found, but only in slovak soils, showing a decrease in the hydraulic conductivity with increasing content of the clay fraction <0.002 mm. these results should contribute to a better estimate of the protective role of soils in groundwater vulnerability maps. 196 geologia croatica 58/2 carpathians mts.) and the slovensky kras mts. (the slovak karst mts.) were studied in slovakia, the istrian peninsula in croatia and the dobratsch mts. (the gailtaler alps) in austria (fig. 1). slovakia the karst area in the brezovske karpaty mts. is built up by triassic carbonates of the jablonica group (carnian wetterstein limestones and dolomites, and upper carnian–norian dolomites). they belong to the nedzov nappe. both limestone and dolomite complexes of the jablonica group are highly permeable, but the karst processes are mainly developed in limestones, producing wide karst joints, caverns and caves. the quaternary of the brezovske karpaty mts. is mainly represented by pleistocene aeolian sediments covering the se foot slopes of plesiva hora, as well as by holocene fluvial sediments and slope sediments (began et al., 1984). the slovensky kras mts. is an area with the most typical karst development in slovakia. these exemplary karst phenomena are on the unesco list of world heritage sites. the research was undertaken on the silicka plateau. in synclinal bedding, the middletriassic limestone–dolomite complex overlies the less permeable to impermeable lower triassic sediments that also occasionally appear on the surface. both complexes belong to the silica nappe (mello et al., 1996). in the sw part of the silicka plateau, the mesozoic complexes are covered by tertiary clays, gravels and sands of the poltar formation. small remnants of these sediments also occur in the eastern part of the area. quaternary sediments are represented mostly by slope debris. fluvial sediments are reduced to brook alluvium (mello et al., 1996). croatia karst terrains cover approximately 50% of croatian territory and predominantly consist of karstified mesozoic and tertiary limestones and dolomites. the istrian peninsula represents the nw part of the spacious adriatic carbonate platform and consists predominantly of carbonate rocks ranging in age from late middle jurassic to eocene, with subordinate eocene siliciclastic rocks, flysch and calcareous breccia, and quaternary terra rossa and loess. the istrian upper middle jurassic to eocene succession can be divided into four large-scale sequences (velić et al., 1995). the 1st, fig. 1 most important carbonate rock outcrops in slovakia, croatia and austria and studied karst areas. 197adamcova et al.: problems of hydraulic conductivity estimation in clayey karst soils 2nd and 3rd of these are composed of carbonates, each terminated by important, lengthy periods of emersion, i.e. type 1 sequence boundaries (tišljar et al., 1998). the 4th large scale sequence consists of carbonate and clastic rocks and unconformably overlies the palaeorelief developed on carbonate rocks. the most widespread sediments in this sequence are flysch deposits. since the formation of flysch, the surface has been affected by tectonics, karst processes and weathering which has led to the development of both surficial and underground features. different types of sediments, polygenetic palaeosols and soils have been formed. for the most part, they irregularly cover all the four aforementioned largescale sequences of istrian carbonates and flysch. austria the dobratsch mt. belongs to the oberostalpin tectonic unit and is very similar to the north part of the karavanken mts. colins & nachtmann (1978) gave a complete description of the geology, beginning from the crystalline basement, through sedimentary rocks of carboniferous and permian ages, up to the triassic complexes that prevail. the dobratsch mt. is mainly built up of the wetterstein-type limestone of ladinian age. it is up to 700 m thick, with deep open vertical fissures. these are mostly of tectonic origin, connected with the major n–s and e–w faults bordering the mountain against the valleys. the upper part of the karstic rock is typically dry, but huge and important karst springs occur at the contact with the “impermeable” werfenian complex at the bottom, in the north, north-east and east. due to the deep circulation along the faults, some thermal springs are also present. the summit of the mountain is built up by reef limestones (ladinian to carnian in age). glacial gravelly moraines are the main quaternary sediments, covering mostly the northern parts of the mountain with a considerable thickness. under the steep southern slopes, huge masses of a prehistoric rockfall can be found, but the slopes are still not stable due to the active periadriatic fault at the foot. 3. materials and methods fifteen soil profiles at eight different locations were studied. table 1 shows the studied sites, together with the numbers of studied soil profiles at each. data on the pedological characteristics of the studied areas, as well as mineral composition of the soil samples have already been described in detail (adamcova et al., 2001, 2002) and will not be presented here. both undisturbed and disturbed soil samples were taken from up to 3 horizons of every studied soil profile, depending on the soil thickness. after a macro-morphological description “on site”, micro-morphological analyses of thin soil sections have been carried out. both the qualitative and the semi-quantitative mineral compositions were studied by xrd. the soils were classified according to isss–isric–fao (spaargaren, 1994) as cambisols (10 profiles), luvisols (4 profiles) and leptosol (1 profile). the following physical properties of the soils were tested on 38 undisturbed samples in the laboratory: – grain size distribution: measured on the <2 mm fraction by combining wet sieving either with the hydrometer method (bs 1377 – part 2, 1990) or with sedigraph; – atterberg limits and plasticity index (necessary for the engineering-geological classification): plastic limit by rolling and liquid limit by the one-point casagrande method, both according to bs 1377 – part 2 (1990); – hydraulic conductivity: determined by up to 3 different laboratory methods: a) permeameter with a triaxial pressure chamber – method also required by soil scientists (stn 72 1020, 1990 – method g); austrian samples have been tested in an other permeameter type, results are incomparable – greifeneder (2000); b) consolidometer: the filtration coefficient kf was calculated from the consolidation curve (dananaj et al., 2005); c) calculation of kf from the grain-size curve: applying the most suitable empirical formulas selected by the pc software geofil; – in order to define the retention ability of the soils regarding heavy metals, other special laboratory tests have also been done that are not discussed here. to complete the data on hydraulic conductivity and to check the results of laboratory tests, field “in situ” tests were carried out using the guelph permeameter, but only in slovakia and austria (greifeneder, 2000; fiala, 1999). country slovakia croatia austria area the small carpathians mts. the slovak karst mt. istria peninsula the gailtaler alps w slovakia e slovakia nw croatia s austria site ardovo (1) plomin (2) (number of dobrá voda (2) silica (2) medulin (2) dobratsch (3) profiles) silicka brezova (1) pekići (2) table 1 location of sampling points (soil profiles). 198 geologia croatica 58/2 4. results and discussion table 2 summarizes the hydraulic conductivity results, showing the mean, minimum and maximum values, specified by the applied method and studied soil type. the mean value of all triaxial tests is 9.47x10-8 m.s-1, but instead of applying this number in any modelling (e.g. zenisova et al., 2002; malik & vojtkova, 2004), the very broad interval between the maximum and minimum should be remembered. in general, lower values with smaller extremes have been measured by the consolidometer method that overestimates the soil “impermeability”. the estimate from grain size produced poor results since no differences were determined between the soils, as the formulas do not include natural porosity or bulk density. although these results are often similar to the results produced by the consolidometer, they are unacceptable, because none of the soils fulfilled the random conditions of the applied formulas (e.g. d10>0.05 mm for the most frequent formula of carman–kozeny) (melioris et al., 1986). all of the studied soils could be classified as clays in the terms of engineering-geological classification (stn 73 1001, 1987). therefore, this computer output is not factually valid, and the method should not be applied to fine-grained soils. as expected, “in situ” tests showed 100 to 1000times higher hydraulic conductivity than the laboratory tests, reflecting the presence of big macro-pores. such pores are usually not present in undisturbed laboratory samples. for this reason, the results of laboratory tests cannot be applied when evaluating the hydraulic conductivity of soils “in situ”, as the differences from reality are too great. the hydraulic conductivity of the studied soils also changes from one horizon to another within the same profile. trends observed by one test method are often opposite to the trends seen by other methods (fig. 2). this is because hydraulic conductivity reflects the simultaneous effect of many different factors, both primary and secondary. grain size is only one of them. in general, the studied croatian soils are finer than similar soils in slovakia which are again finer than the austrian ones. no real correlation between grain size and hydraulic conductivity tested in the triaxial permeameter could be found. only a very weak descending trend with the increasing content of the clay fraction (<0.002 mm) could be observed (fig. 3), similar to the results of the consolidometer method (fig. 4). there was no correlation between the contents of the whole fine fraction <0.063 mm and kf (fig. 5). a very draft estimate of the filtration coefficient kf from the content of the clay fraction might be possible, but only for slovak soils despite the soil type. here, an exponential trend was found, however, the reliability is very low (fig. 6). the differences between the classified soil types are small. however, some differentiation can be seen looking at the results of field tests (fig. 7). unfortunately, there are not enough data on the leptosols. surprisingly, the leptosol from silica yielded the lowest hydraulic conductivity in the triaxial test: 3.5x10-11 m.s-1 in the uppermost horizon (depth 0–10 cm). however, this was probably due to imperfections in the method (secondary method kf (m.s-1) all soils cambisol luvisol leptosol permeameter with number of tests 30 19 9 2 triaxial pressure mean value 9.47x10-8 8.89x10-8 7.17x10-8 2.60x10-7 chamber minimum 3.50x10-11 1.45x10-10 1.97x10-10 3.50x10-11 maximum 5.83x10-7 3.97x10-7 5.83x10-7 5.22x10-7 number of tests 33 23 8 2 consolidometer mean value 7.13x10-9 6.50x10-9 8.22x10-9 1.00x10-8 minimum 9.40x10-10 9.40x10-10 1.40x10-9 7.02x10-9 maximum 3.59x10-8 1.73x10-8 3.59x10-8 1.30x10-8 number of tests 40 26 12 2 geofil (grain size) mean value 2.98x10-9 2.17x10-9 2.78x10-9 1.56x10-9 minimum 1.01x10-9 1.08x10-9 1.01x10-9 1.21x10-9 maximum 9.96x10-9 9.96x10-9 4.11x10-9 1.92x10-9 number of tests 51 23 22 6 guelph mean value 9.33x10-6 8.20x10-6 1.28x10-5 9.67x10-7 permeameter minimum 8.09x10-9 1.13x10-8 5.63x10-8 8.09x10-9 maximum 6.88x10-5 5.49x10-5 6.88x10-5 2.36x10-6 la bo ra to ry fi el d table 2 hydraulic conductivity of studied soil types – results of four test methods. 199adamcova et al.: problems of hydraulic conductivity estimation in clayey karst soils factor). the chamber pressure might compact the very loose sample. also 15 cm deeper, the volume reduction after the test reached 16%. the highest hydraulic conductivity measured by this method was 5.8x10-7 m.s-1 in the upper luvisol sample from dobra voda 2, probably due to many roots and cracks (primary factor) and short saturation before the test (secondary factor). fig. 2 different test methods yielded partly opposing trends of hydraulic conductivity variability with depth. legend: a – permeameter with triaxial chamber; b – consolidometer; c – geofil; d – guelph field permeameter. fig. 3 hydraulic conductivity – results of tests using the permeameter with a triaxial pressure chamber. a – distribution according to soil type; b – distribution according to country. a b 200 geologia croatica 58/2 sometimes the changing kf could be easily explained by the mineralogy, e.g. in slovak samples containing smectite (dobra voda, silica). here, permeability decreased considerably during 2 weeks in the triaxial chamber, as the pores were closed due to smectite swelling (fig. 8). both the degree and duration of saturation, as well as porosity are very important, whereby these factors are in very close relationships in soils containing swelling clay minerals. there, the results of “in situ” tests are very season-dependent. in the autumn, fig. 4 hydraulic conductivity – results of tests using the consolidometer. a – distribution according to soil type; b – distribution according to country. a b fig. 5 hydraulic conductivity – results of tests using the guelph field permeameter, related to the content of the whole fine fraction (silt and clay). a – distribution according to soil type; b – distribution according to country. 0.1 1 10 100 1000 70 80 90 100 content of the fraction <0.063 mm (%) cambisol luvisol leptosol 0.1 1 10 100 1000 70 80 90 100 sk a content of the fraction <0.063 mm (%) 0.1 1 10 100 1000 70 80 90 100 content of the fraction <0.063 mm (%) cambisol luvisol leptosol 0.1 1 10 100 1000 70 80 90 100 sk a content of the fraction <0.063 mm (%) a b 201adamcova et al.: problems of hydraulic conductivity estimation in clayey karst soils when the soil was highly saturated for long periods, considerably lower hydraulic conductivity (10-8 m.s-1) was measured in dobra voda than in the hot dry summer (10-5–10-6 m.s-1). this also explains the fact that slovak luvisols (containing smectite) seem to be slightly less permeable than cambisols (without smectite) in the lengthy triaxial tests, having enough time for the smectite expansion, but are more permeable during the short field tests by good weather. it can be concluded that if any accident with liquid pollutants occurs on the surface covered with expandable soils (here the luvisols), the chance of successful remediation and prevention of groundwater contamination is high in the wet seasons, when the soil is saturated for long periods, but the groundwater vulnerability is very high there in dry seasons, due to the occurrence of contraction cracks. in older soils, without smectite, secondary compaction can lower the effective porosity and thus the hydraulic conductivity. this was observed in the uppermost horizons at the dobratsch mt. due to cattle grazing (figs. 9 and 10), but the primary compacting effect of the geostatic pressure was also evident in the deeper horizons of thick soils in slovak samples. fig. 6 increasing content of the clay fraction should reduce the hydraulic conductivity. however, this trend could be proved only within the field tests on slovak soils. unfortunately, no field tests could be done at the croatian profiles yet. fig. 7 hydraulic conductivity – results of tests using the guelph field permeameter, related to the content of the clay fraction. a – distribution according to soil type; b – distribution according to country. a b 202 geologia croatica 58/2 5. conclusions the detailed study illustrates the difficulties and the complexity of the problem of determining the hydraulic conductivity of soils. this should be taken into account when preparing a methodology for groundwater vulnerability mapping (malik & svasta, 1999; marschalko & ides, 2000). some attempts have already been published, where the assessment of soil permeability was based solely on an field estimate of the content of the clay fraction. but, such results are far away from the hydraulic conductivity measured “in situ”. therefore, the methodology needs further development, based on results collected from many field tests and maybe sorted according to the exact soil type in terms of soil science (the weather conditions during the test period should be also taken into account). this would allow soil maps to be used as an important input for groundwater vulnerability mapping. acknowledgement we gratefully acknowledge the research support scheme of the open society foundation (project no. 1326/2000), action austria–slovakia (projects no. 37s11 and 42s6), as well as the slovak granting agency vega (project no. 1/9160/02) for financial support. 6. references adamcova, r., dubikova, m., skalsky, r., durn, g., miko, s., kapelj, s. & ottner, f. (2001): vyskum vybranych typov pod ako barier znecistenia podzemnych vod anorganickymi latkami [research of the barrier effect of selected soil types against inorganic groundwater pollutants – in slovak].– conf. proceedings hydrogeochemia ‘01, sah, bratislava, 27–34. adamcova, r., durn, g., miko, s., skalsky, r., kapelj, s., dubikova, m. & ottner, f. (2002): soil cover as pollution barrier in karst areas – brief summary of research results.– prace wydziału nauk o ziemi uniwersytetu śląskiego, 22, 9–17, sosnowiec. began, a., hanacek, j., mello, j. & salaj, j. (1984): geologicka mapa myjavskej pahorkatiny, brezovskych a cachtickych karpat 1:50000 [geological map of the myjavska upland, the brezovske and the cachticke karpaty mts. – in slovak].– guds, bratislava. bs 1377 – part 2 (1990): british standard methods of tests. part 2: soils for civil engineering.– british standards institution, london, 62 p. colins, e. & nachtmann, w. (1978): geologische karte der villacher alpe (dobratsch), kärnten [geological map of the dobratsch mt. – in german].– mitteilungen der ges. geol. bergbaustud. oesterr., 25, vienna. dananaj, i., frankovská, j. & janotka, i. (2005): the influence of smectite content on microstructure and geotechnical properties of calcium and sodium bentonites.– applied clay science, 228, 223–232. fiala, k. (ed.) (1999): zavazne metody rozborov pod [obligatory methods of soil analyses – in slovak].– vúpaop bratislava, 139 p. greifeneder, s.m. (2000): wasserhaushalt und mineralogische eigenschaften der böden im einzugsgebiet der unionund thomasquelle am dobratsch in kärnten [water balance and mineralogical properties of soils in the infiltration area of union and thomas springs in the 0 5 10 15 20 25 0 5000 10000 15000 20000 25000 time (min) k f 10 x 10 8 (m .s-1 ) fig. 8 decreasing hydraulic conductivity of the soil from dobra voda (depth 20–30 cm), due to smectite swelling during two weeks of the triaxial test (recalculated to the temperature of 10°c). fig. 9 on the meadows of the dobratsch mt. (austria), the hydraulic conductivity of the thin soil cover may be very low even without swelling clay minerals, being highly compacted by cattle. after the rain, water remains in flat depressions for several days. fig. 10 detail from the dobratsch mt., showing precipitation water on the surface. 203adamcova et al.: problems of hydraulic conductivity estimation in clayey karst soils dobratsch mt. in austria – in german].– unpubl. bsc. thesis, iag boku, vienna, 83 p. malik, p. & svasta, j. (1999): reks – an alternative method of karst groundwater vulnerability estimation. hydrogeology and land use management.– proceedings of the xxix congress of iah, bratislava, 79–85. malik, p. & vojtkova, s. (2004): groundwater vulnerability assessment of tisovec karst using physically-based approaches of contamination spreading.– podzemna voda, x/1, 70–81, bratislava. marschalko, m. & ides, d. (2000): vyuzivani souboru ucelovych map [use of special purpose maps – in czech].– zbornik konf. recyklace odpadu iv, všb – tu ostrava, 185–189. melioris, l., mucha, i. & pospisil, p. (1986): podzemna voda – metody vyskumu a prieskumu [groundwater – methods of research and survey – in slovak].– alfa, bratislava, sntl, praha, 429 p. mello, j., elecko, m., pristas, j., reichwalder, p., snopko, l., vass, d. & vozarova, a. (1996): geologická mapa slovenského krasu 1:50000 [geological map of the slovensky kras mts. – in slovak].– guds, bratislava. spaargaren, o.c. (ed.) (1994): world reference base for soil resources. draft.– isss–iris–fao, wageningen/ rome. stn 72 1020 (1990): laboratorne stanovenie priepustnosti zemin [slovak technical standard. laboratory determination of soil permeability – in slovak].– unm, praha, 78 p. stn 73 1001 (1987): zakladova poda pod plosnymi zakladmi [slovak technical standard. foundation of structures. subsoil under shallow foundations – in slovak].– unm, praha, 80 p. tišljar, j., vlahović, i., velić, i., matičec, d. & robson, j. (1998): carbonate facies evolution from the late albian to middle cenomanian in southern istria (croatia): influence of synsedimentary tectonics and extensive organic carbonate production.– facies, 38, 137– 152. velić, i., tišljar, j., matičec, d. & vlahović, i. (1995): opći prikaz geološke građe istre (a review of the geology of istria).– in: vlahović, i. & velić, i. (eds.): lst croatian geological congress, excursion guide-book, zagreb, 5–30. zenisova, z., flakova, r. & adamusova, a. (2002): hydrogeochemical modelling in porous and karst-fissure media.– prace wydziału nauk o ziemi uniwersytetu śląskiego, 22, 233–240, sosnowies. manuscript received october 14, 2004. revised manuscript accepted november 11, 2005. 204 geologia croatica 58/2 gabrovsek.indd 187 � ab stra ct karst ground water dynamics between the planinsko polje and the springs of ljubljanica (slovenia) was studied based on the monitoring of stage and temperature of ground water in four caves. the unica river, which fl ows over the planinsko polje, and sinks at its e and n rim, is considered as the main input to the observed system. at small fl ood events its role is none or questionable. at medium and large events, when the discharge of unica exceeds 25 m3/s, it becomes an important and/or the dominant input to the system. when the capacity of the primary (eastern) ponors in the polje is exceeded, the stage in a cave, which is fed solely through these ponors, reaches the plateau followed by a very slow recession. the surplus fl ow goes towards northern ponors causing a fast rise of the stage in adjacent to them. in two of the northernmost caves, the stage response is almost identical, but the temperature variations are different. the uniform water level suggests a highly permeable region bounded by a low permeability barrier in the down-fl ow direction, while different temperature behavior indicates a different origin of the waters for each cave. keywords: ground water fl ow, caves, fl ood pulse, recharge, hydrographs, slovenia observations of stage and temperature dynamics in the epiphreatic caves within the catchment area of the ljubljanica river (slovenia) � franci gabrovšek and janez turk karst research institute, zrc sazu, postojna, titov trg 2, slovenia; (gabrovsek@zrc-sazu.si; janez.turk@zrc-sazu.si) doi: 104154/gc.2010.16 geologia croatica 63/2 187–193 7 figs. zagreb 2010 geologia croaticageologia croatica 1. introduction the springs of the ljubljanica river drain more than 1100 km2 of karst area in central and south-east slovenia (šušteršič, 2000). the catchment comprises a vegetated karst surface and a series of karst poljes, including the periodically fl ooded cerkniško and planinsko poljes. water from the poljes fl ows underground towards the springs of ljubljanica, at the rim of the ljubljana basin. intensive hydrogeological investigations of the area have been carried out for more than a century. among others, the tracing tests of gospodarič & habič (1976) have shown clear connections between the ponors and springs. however a more detailed picture of groundwater dynamics in the aquifer is still needed. part of the system, related to this study, is shown on fig. 1. the level of karst ground water between the planinsko polje and springs of the ljubljanica river can be reached through several caves. some of these are in the imediate vicinity of the planinsko polje, close to the ponors. only three caves reach the level of groundwater further downstream in the direction of the springs (fig. 1): gradišnica was explored geologia croatica 63/2geologia croatica 188 more than a century ago, while vetrovna jama pri laški kukavi (vetrovna jama = windy cave) and gašpinova jama have been discovered and explored during the last decade. we established simultaneous and continuous logging of ground water level and temperature in these three caves and in najdena jama, which is in the immediate vicinity of the northern rim of the planinsko polje. the study had two main goals: to determine the groundwater dynamics in the described system by analyses of stage and temperature hydrograms, and to demonstrate the potential use of caves as points of groundwater monitoring. 2. description of the studied area all the monitored caves belong to the ravnik area, which is comprised of a well-karstifi ed cretaceous limestone with patches of dolomite. a more impermeable triassic dolomite forms the bottom of the planinsko and cerkniško poljes (see fig. 1) (pleničar et al., 1970). the unica river emerges at the contact of the cretaceous strata with the triassic dolomite and fl ows across the planinsko polje, sinking again at the eastern and northern margin of the polje. cerkniško, planinsko and logaško poljes are covered by the quaternary sediments. recharge of the system recharge of the studied system is complex. the majority of water comes from the ponors of the unica river at the eastern and northern rim of the planinsko polje. the unica is not a typical allogenic river it has several karstic springs at the southern rim of the polje and acts as an overfl ow of the waters arriving from the cerkniško polje, the pivka basin and javorniki mountains to the south. the complexity and origin of the unica are not the concerns of this paper, but it is simply considered as a sinking river providing input to the observed system. some of the water in the observed caves may originate directly from the cerkniško polje. its direct connection to the springs at bistra has been proven by dye tracing (gopodarič & habič, 1976). another area of recharge is a dolomitic region in logaške rovte to the west. two surface streams emerge and sink in this area. these streams are much smaller than the unica river, but can play some role at specifi c hydrological events. the logaščica sinks in the town of logatec, which is downstream (north) of all the observed caves. the ponor is in the proximity of gašpinova jama, and it could also have an infl uence on the stage in gradišnica. hotenka sinks further ssouth-west most probably joins the system in the region where the observations were made. however, this has not been proven so far. the only data available concerns the discharge of the unica and precipitation. other recharge data is lacking. discharge of the unica was measured downstream from all the springs and about 5 to 6 km upstream from the eastern ponors, and 16 km upstream from the northern ponors. these ponors are the main, but not the only sinking points, as the river leaks at many other locations along its meandering course over the planinsko polje. mean annual discharge of the unica river at the gauging location is 26 m3/s, the minimum is a few cubic metres per second and the maximum may be more than 100 m3/s (breznik, 1988). the polje starts flooding when discharge is greater than 60 m3/s (šušteršič, 2002). 3. materials and methods 3.1. the data sources to measure and log pressure and temperature of water, we used schluberger divertm instruments, which were fi xed to cave walls at selected locations (fig. 2). pressure is converted to the height of the water column. the temperature and pressure accuracy is 0.1 °c and ±0.2 % of the measurement range respectively. the instruments are programmed via an optical bridge using a pc or a pocket pc. the storage capacity is 24000 readings in fi xed or event based time intervals. during this study a time interval of 30 minutes was chosen. based on experiences from similar systems (gabrovšek & peric, 2006) this interval was considered suffi ciently short to record all the important variations and separate the arrival of fl ood pulses to different measurement points. the loggers were relatively remote in the caves, figure 1: a generalized geological map of the study area. the position of the observed caves, surface waters and presumed directions of groundwater fl ow are indicated. gabrovšek and turk: observations of stage and temperature dynamics in the epiphreatic caves within the catchment area of the ljubljanica river (slovenia) geologia croatica 189 therefore their autonomy was important to avoid too many trips; 30 min intervals with 24000 readings gives 16 months recording before the logger’s memory is full. daily precipitation data from planinsko polje (station planina, fig. 1) were obtained from the environmental agen cy at the ministry of the environment and spatial planning of slovenia. the system was observed between june 2006 and december 2007, although all stations were not active during the whole period. records from vetrovna jama and najdena jama are missing for spring 2007. the unica river was monitored from september 2006 and the cerkniško polje after may 2007. 3.2. temperature variations the highest temperature changes in the system occur during the fl ood events when an event water with different temperature invades the system. waters of different origin carry different temperature signals. as a surface river, the unica river exhibits diurnal variations of temperature with amplitudes of up to 2 °c at the point of observation. amplitudes become higher further downstream at ponors and sometimes even in the caves. there is no other source of diurnal temperature variations besides the unica. these variations, mainly driven by shortwave solar radiation, are preserved along the underground fl ow, although the amplitude decreases because of the heat exchange with the streambed and surrounding rocks (wicks, 1997; gu & li, 2002). for the observed system, the presence of diurnal temperature variations in any of the caves shows the presence of the sinking unica river. assuming that the temperature signal is dominantly transported by advection, the phase shift between the temperature maxima and minima in the river and at observation points in the caves or between the two observation points in the caves is a good approximation for the transit time of water between the different locations (stonestrom & constantz, 2003; birk et al., 2004). 4. results figure 3 shows precipitation at planina, stage and temperature hydrograms in caves and a fl ow and temperature hydrogram of the unica river for the period between september 10th and october 20th, 2007. grey areas numbered 1 to 3 denote three events discussed in detail below. they occurred in an increasing order of magnitude. small event (fig. 4a) presents the hydrographs of event 1 from fig. 3. it was triggered by 30 mm of rain on september 11th, 2007. the discharge of the unica increased from 4 m3/s to 6 m3/s. the stage hydrograms of gradišnica and gašpinova jama are very similar and symmetrical. in contrast, a fast response in najdena jama is followed by slow recession. such a response could be caused by local runoff from the neighbouring planinsko polje or a fast fl ow of autogenic origin. figure 3: stage and temperature hydrographs of the four monitored caves, cerkniško polje (yellow) and the unica river for the period between september 10th and october 20th, 2007. shaded areas numbered 1 to 3 represent three events which are discussed in more detail and shown in figs 4a–c. figure 2: data logger in a cave (left) and connected to a pc via optical bridge (right). geologia croatica 63/2geologia croatica 190 the stage hydrograph in vetrovna jama shows a double peak; it cannot be resolved if the peaks belong to waters of different origins or if it is simply the consequence of the temporal distribution of rainfall intensity. the peak stage in all caves precedes the peak fl ow of the unica, and it hterefore follows that the recharge of unica has little importance for small events. there was no temperature change in najdena jama and gradišnica. the step change of temperature in gašpinova jama is apparent, as the sensor had been above the water surface prior to the event (in other caves the sensor is always below the water surface). there is a slight decrease of temperature in vetrovna jama. a medium event (event 2, fig. 4b) was triggered by rain on september 18th and 19th. the fi rst peaks in the stage hydrographs correspond to those in figure 4a. they all precede the peak fl ow of the unica river. the stage hydrographs in gradišnica and gašpinova jama are almost identical. the stage hydrograph in vetrovna jama has one broad peak. a clear infl ection point in the rising limb probably corresponds to the fi rst peak of event 1, but the peak is not clear as it is overprinted by the arrival of the main water which raises the stage to 13 m. secondary peaks in gradišnica, gašpinova jama and najdena jama are clearly following the peak fl ow of unica. there are no temperature variations in najdena jama and gradišnica. the temperature hydrogram in gašpinova jama shows the additional step change (indicated by the arrow in figure 4b), which is not present in any other cave. such a step change also occurs at other similar events (not presented here) and probably indicates a local infl ow. there is a clear increase in water temperature in vetrovna jama caused by surface water. it shows no clear correlation with the temperature of the unica river. however, the river is heated between the observation points and the ponors and it is possible that the temperature remains higher until water reaches the cave. but, diurnal variations are not present in the cave, which is in confl ict with the previous argument. temperature hydrographs of the unica and vetrovna jama for other similar events (not presented here) are clearly correlated (turk & gabrovšek, 2009). a large event (event 3, fig. 4c) was triggered by two consecutive rainfall events between september 28th and 30th and on october 7th. peak fl ows of the unica were 54 m3/s and 51 m3/s respectively. the initial stage response in all caves resembles that of small and medium events. the peaks precede the peak fl ow of the unica, but are immediately followed or masked by a much larger secondary peak. a stage hydrograph in gradišnica and gašpinova jama shows only small differences. the maximum rise is 36 m in gradišnica and 33 m in gašpinova jama. recession is well correlated with the recession of the unica. the stage hydrograph in najdena jama shows several small peaks prior to the large one, when the stage rises to 25 m. the hydrograph in vetrovna jama is different. the initial peak turns into a steep rise of stage to 17 m. the second event caused another peak at 16 m again followed by a slow recession. figure 4a: hydrographs for event 1. figure 4b: hydrographs of event 2. the green arrow indicates a step change in gašpinova jama (see text). figure 4c: hydrographs of event 3. gabrovšek and turk: observations of stage and temperature dynamics in the epiphreatic caves within the catchment area of the ljubljanica river (slovenia) geologia croatica 191 a slow recession followed, until discharge of the unica dropped below 13 m3/s, when a faster recession began. such stage hydrographs are typical for vetrovna jama for all large events. a fast initial rise to 15–18 m followed by a slow recession until the discharge of the unica drops below 13 m3/s. temperature hydrograms show clear diurnal variations in vetrovna jama and najdena jama. when the discharge of the unica is above 30 m3/s, diurnal variation of temperatures is also present in gradišnica. figure 5 shows the details of event 3. a characteristic change of temperature in najdena jama appears 9 hours latter in gradišnica. the same lag in both caves is recorded between diurnal maxima. diurnal temperature variations ''fade out'' in gradišnica when the discharge of the unica drops below 30 m3/s. the temperature variations in gašpinova jama are different. the step increase in temperature is followed by an infl ow of relatively colder water at the fi rst fl ood event. the temperature is only slightly disturbed at the second event. diurnal temperature variations in gašpinova jama are present only at events, when the discharge of the unica exceeds 60 m3/s. direct recharge from the cerkniško polje so far we have not commented on the hydrographs obtained in the cerkniško polje which are also shown on fig. 3. the instrument was installed into the ponor at the bottom of the lake. these ponors are fed by the stržen stream which fl ows over the polje. although the stream "leaks" into the observed ponors, most of its fl ow continues to the series of ponor caves at the western rim of the polje, which are part of the unica catchment. the capacity of the observed ponors is low (probably below a few hundred litres per second). this is also demonstrated by the data shown on fig. 3, where the observed area was fi lled during most of the time, except for the two short periods following very dry weather in september. tracing tests in the 1970s (gospodarič & habič, 1976), showed that water from the observed ponors preferentially fl ows directly to the ljubljanica springs therefore we expected to sense this water in some of our caves, particularly in vetrovna jama. however the data show no clear sevidence of this. neither stage nor temperatures in any of the caves show clear correlations with the cerkniško polje. if a connection exists, recharge from the lake should be small compared with the recharge from the unica river and other sources. 5. discussion the observations described above are also representative of additional events not presented here. differences between the events exist due to the variable distribution of rainfall intensity in the recharge zone, which is a topic for future study. however, there are several characteristics of the system, which are observed during all events. almost identical stage, but considerably different temperatures show that gradišnica and gašpinova jama are hydraulically well connected, but they belong to different fl ow paths within the aquifer. only at extremely high fl oods, when the discharge of the unica approaches 60 m3/s, do temperatures in these two caves almost equalise. the water table in this part of the aquifer is very uniform; it is about 70 m above the spring level at vrhnika. between gašpinova jama and the spring of ljubljanica, no other known cave reaches the water level. these facts indicate the presence of a relatively impermeable barrier downstream from the region of the two caves. such a barrier would explain a uniform water table in the very conductive zone upstream. a candidate for the low permeability zone is a band of triassic dolomite that extends in a nw-se direction north of the observed caves as shown schematically on fig. 7. during the observation period the stage in vetrovna jama never rose above 19.5 m. it remains high until the discharge of the unica falls below 13 m3/s. when the stage in vetrovna jama approaches its maximum, the unica invades through northern ponors, resulting in a large increase of stage and the occurrence of diurnal temperature variations in najdena jama and gradišnica. these observations suggest a limited capacity for the eastern ponors. when this is reached, higher discharge of the unica has no infl uence on the stage in vetrovna jama, all the surplus fl ow goes to the northern ponor causing a massive infl ow in the region of najdena jama. however, we should also be aware that the eastern ponors are located at different altitudes and when discharge increases suffi ciently, and then additional ponors are activated. this may explain the highest peaks on the stage hydrographs in vetrovna jama (see peaks above the »plateau« on fig. 3). flow from najdena jama continues towards the north and reaches gradišnica in several hours. only when the discharge of the unica drops below 13 m3 does the outfl ow in vetrovna jama become larger than the infl ow and faster stage recession starts. such benaviour could also be explained by the divergence of subterranean fl ow (turk & gabrovšek, 2009). the stage in caves which are close to the points of concentrated recharge is often determined by hydraulic restriction from channels of small diameter, breakdowns etc. the rate of change of stage in front of such restrictions is figure 5: detail of event 3, showing a delay between the temperature signals in najdena jama and gradišnica. geologia croatica 63/2geologia croatica 192 dh/dt = a(h) x (qin–qout), where qin and qout are input and output fl ow rates and a(h) is the area of the water surface at height h. (gabrovšek & peric, 2006). stage hydrograms in such scenarios show fast rise and slow recession. najdena jama and to some extent vetrovna jama also fi t into this category. the input to caves which are deeper in the system is fi ltered by the upstream restrictions, therefore hydrograms become more symmetrical. such are the stage hydrographs of gradišnica and gašpinova jama, but use of a simple reservoir-restriction model is questionable here. these caves can be considered as natural piezometers in an aquifer with a well developed and braided conduit system. fig. 6 shows an elevation profi le of the terrain between planinsko polje and ljubljana basin. very generalised profi les of the observed caves are shown and some conclusions as to the groundwater level and direction as obtained by this study are presented. selection criteria for the observation points within the cave have not been discussed and, depending on the role and position of a cave in an aquifer, this can be an important issue. for example, fig. 7 shows a generalized cross-section of gradišnica and an extract from event 3. the instrument is located in the terminal lake at a depth of 220 m as indicated on figure 7a. during small and medium events the level of the lake oscillates, but there is no or only minor fl ow of the event water and temperature changes through the site. at large events, when the recorded stage is higher than 20–23 m, the lake water rises to the level of the large putick´s chamber and fl ows to a system of channels on the other side of the chamber. the event water passes the observation point as can be seen from the temperature hydrographs which exhibit large and even diurnal variations. for all large events, the stage hydrograph in gradišnica has an infl ection point at about 22 m. this is valid for both limbs of the hydrograph. at this level the water from the lake starts to fi ll putik´s chamber which has a large storage capacity. as the rate of change of stage is inversely proportional to the surface of the area that the water fi lls or drains, the rise and drop of the stage is reduced when the water level is at the position of the largest surface area. 6. conclusion monitoring enabled a new insight into the aquifer. caves are important windows to the groundwater and representative observation points. however, the study posed more questions than answers. further research should be undertaken in order to delineate the sources of recharge. the fl ow and sinking of the unica river should also be investigated in more detail. results should be compared to the results of monitoring at the springs. although the planinsko polje fl oods regularly at least once per year, it was not fl ooded during our study. to this extent figure 6: an elevation profi le of the area between planinsko polje and ljubljana basin in an approximate north-south direction. the cross-sections of the caves are generalised and simplifi ed. vetrovna jama is shifted to the south, because it would overlap with najdena jama if positioned correctly. this way its connection to eastern ponors is emphasised. dashed lines show the estimated level and direction of groundwater fl ow. figure 7: a) simplifi ed cross-section of gradišnica adapted from nagode (1997) with the position of the observation point and assumed fl ow direction at high fl oods. b) detail of event 3 with the infl ection in the stage hydrograph, which occurs when the putick’s chamber is fi lled and emptied. gabrovšek and turk: observations of stage and temperature dynamics in the epiphreatic caves within the catchment area of the ljubljanica river (slovenia) geologia croatica 193 important information on what happens when the polje is fl ooded for few weeks was missed. ironically, it was fl ooded twice within a few months after the monitoring ceased. acknowledgement the authors would like to thank members of logatec caving club, especially mr. bojan volk, who assisted the work in gašpinova jama and vetrovna jama. references birk, s., liedl, r. & sauter, m. (2004): identifi cation of localized recharge and conduit fl ow by combined analysis of hydraulic and physico–chemical spring responses (urenbrunnen, sw–germany).– journal of hydrogeology, 286, 179−193. breznik, m. (1998): storage reservoirs and deep weels in karst regions.– a.a. balkema publishers, rotterdam, 251 p. gabrovšek, f. & peric, b. (2006): monitoring of the fl ood pulses in the epiphreatic zone of karst aquifers: the case of reka river system, karst plateau, sw slovenia.– acta carsologica, 35/1, 35–45. gospodarič, r. & habič, p. (1976): underground water tracing – investigations in slovenia 1972–1975.– institute for karst research sazu, ljubljana, 309 p. gu, r.r. & li, y. (2002): river temperature sensitivity to hydraulic and meteorological parameters.– journal of environmental management, 66, 43–56. nagode, m. (1997): novejše raziskave v gradišnici.– naše jame, 1/1, 21–36. pleničar, m. (1970): tolmač osnovne geološke karte 1:100000, list postojna l 33−77 [basic geological map of sfry 1:100000, geology of the postojna sheet − in slovenian].− geološki zavod ljubljana, zvezni geološki zavod, beograd, 69 p. stonestrom, d.a. & constantz, j. (2003): heat as a tool for studying the movement of ground water near streams. − u.s. geological survey, reston, virginia, 96 p. http://pubs.water.usgs.gov/ circ1260/ šušteršič, f. (2000): speleogenesis in the ljubljanica river drainage basin, slovenia. in: speleogenesis, evolution of karst aquifers.− in: klimchouk a.b., ford d.c., palmer a.n., & dreybrodt w. (eds.): national speleological society, hunstville, 397–406. šušteršič, f. (2002): where does underground ljubljanica fl ow?– materials and geoenvironment, 49/1, 61–84. turk, j. & gabrovšek, f. (2009): hidrogeologija vetrovne jame v vodonosniku severno od planinskega polja (hydrogeology of cave vetrovna jama in karst aquifer north from planinsko polje).– geologija, 52/1, 137–144. wicks, c.m. (1997): origins of groundwater in a fluviokarst basin: bonne femme basin in central missouri, usa.– hydrogeology journal, 5/3, 89–96. manuscript received december 23, 2009 revised manuscript accepted june 14, 2010 available online june 28, 2010 geologia croatica 63/2geologia croatica 194 03 segovic.indd 19 � 1. introduction in car bo na te ter rai ns goet hi te is a com mon pa ra ge ne tic mi neral in soi ls, par ti cu lar ly in ter ra ros sa, and is al so fou nd as princi pal con sti tue nt of fe-cre tes or it can be tra ced as the ma jor pha se in so me mi ne ral de po si ts in kar sti fi ed areas. the se kin ds of goet hi te ap pea ran ce are ob vious ly con trol led by weat he ri ng whi ch cause an en vi ron me nt fa vou ri ng for ma tion of aci dic so lu tio ns. the type and exte nt of goet hi te mi ne ra li za tion is de pen de nt on the geoc he mi cal abi li ty and amou nt of sub stra te avai lab le du ri ng the weat he ri ng pro ces ses. the mi ne ra li za tion has col lo mor ph textu res; goet hi te is low al-sub sti tu ted and poor ly crystal li zed. this wo rk pro vi des evi den ce of a com ple te ly dif fe re nt ki nd of goet hi te mi ne ra li za tion in the ad ria tic seg me nt of the ad ria ti c-di na ri de car bo na te plat fo rm, wi th the type lo ca li ty oc cur ren ce in the br bin šći ca co ve on du gi otok (cen tral ad riatic). he re, ve ry fi ne ag gre ga tes of we ll crystal li zed, al-sub stitu ted and stoi chiomet ric goet hi te, ac com pa nied by coar se grained cal ci te in fi ll sha rp tec to nic cre vi ces and in te r-bed di ng pla nes in the up per cre ta ceous li mes to nes. the mi ne ra li za tion sug ges ts pre ci pi ta tion from a ba sic so lu tion and a deep pla ced sour ce, ri ch in fe, al, si and p. he re, we pre se nt a set of xray dif frac tion (xrd), scan ni ng elec tron mic ros co pe (sem) and elec tron pro be mic roa na lyses (epma) mi ne ra lo gi cal and geoc he mi cal da ta on the goet hi te mi ne ra li za tion. the ori gin of the mi ne ra li za tion is dis cus sed and its sig ni fi can ce on a re gio nal sca le is stres sed in re ga rd to the nor the rn sub mer ged seg me nt of the ad ria mic rop la te. 2. geo lo gi cal set ti ng and mi ne ra li za tion textu res du gi otok, as pa rt of the ad ria tic car bo na te plat fo rm, be lon gs to the di na ri dic oro ge nic moun tain chain whi ch was fi nal ly sha ped by exten si ve sea le vel ri se du ri ng the ho lo ce ne deg labra ni mir šegvić1, boš ko lugović1, ne ven tadej1, vla di mir bermanec2, and lov ro panjkota1 ab stra ct at the we stern seawa rd coa st of the is la nd of du gi otok, unu sual goet hi te mi ne ra li za tion oc cu rs as the in fi l li ng of a system of thin cre vi ces in the up per cre ta ceous li mes to nes of the ad ria tic car bo na te plat fo rm. goet hi te is excep tional ly we ll or de red and shows a va rie ty of che mi cal com po si tio ns ran gi ng from al mo st pu re feo·oh to al-sub sti tu ted com po si tion ac com pa nied by hi gh si and p im pu ri ty. the most cha rac te ris tic textu ral type as sem bla ges are goet hi te and coar se grained cal ci te in com po si te ag gre ga tes. these ag gre ga tes con tain al-sub sti tu ted goet hi te wi th me ta morphic si li ca te mi ne ra ls em bed ded in the co re (bla ck goet hi te), ar mou red by the xr d-pu re, al mo st stoi chiomet ric goethi te (brown goet hi te). the geoc he mi cal and mi ne ra lo gi cal fea tu res of the mi ne ra li za tion sug ge st an as cen di ng so lution from a hid den me ta mor phic sour ce. we spe cu la te that the sour ce cou ld ha ve been ac ti va ted by the ther mal in fl ux lin ked to the plio ce ne in trap la te mag ma ti sm in the eas te rn seg me nt of ad ria. keywor ds: al-goet hi te, stoi chiomet ric goet hi te, crysta loc he mis try, en do ge nic ori gin, du gi otok, adriatic sea, ad ria mic rop la te, croatia 1 fa cul ty of mi ni ng, geo lo gy and pet ro leum en gi nee ri ng; uni ver si ty of zag reb, pie rot ti je va 6, hr-10 000 zag reb, croa tia (bseg vic@r gn.hr; bseg vic @geos.uni-heidelberg.de, bosko.lugovic@rgn.hr, neven.tadej@ rgn.hr, lovro.panjkota@rgn.hr) 2 institute of mineralogy and petrology, de par te me nt of geology, fa cul ty of scien ce, uni ver si ty of zag reb, hor va to vac bb, hr-10 000 zag reb, croa tia (vberman@public.carnet.hr) si-p im pu re al-goet hi te mi ne ra li za tion on the is la nd of du gi otok (cen tral ad ria tic, croa tia) geologia croatica 61/1 19–26 7 figs. 3 tabs. zagreb 2008 geologia croaticageologia croatica � 03 segovic.indd 1903 segovic.indd 19 24.6.2008 11:06:2024.6.2008 11:06:20 geologia croatica geologia croatica 61/1 20 cia tion (fig. 1). the is la nd con sis ts en ti re ly of up per cre taceous do lo mi tes and li mes to nes showi ng va rious kar sti fi cation mor pho lo gies (džaja, 2003). goet hi te mi ne ra li za tion oc cu rs exclu si ve ly alo ng the wes te rn seawa rd coa st of the is la nd, as the in fi l li ng of in ter beddi ng pla nes (fig. 2a) and sub ver ti cal ly, up to 10 cm thi ck tec to nic cre vi ces in the ho st li mes to nes (fig. 2b) whi ch abundan tly con tain chon dro don ts and rudists of the cenomanian age. goet hi te mi ne ra li za tion shows three textu ral types. mi nera li za tion of textu ral type 1 is con fi ned to the vei ns in si de the ho st li mes to nes fi l led wi th a para ge ne tic as sem bla ge con sisti ng of ag gre ga tes of sub mic ro nic goet hi te and eu hed ral coar se grai ned cal ci te (fig. 3a). due to the mic ros co pic to sub micros co pic si zed si li ca te mi ne ral im pu ri ties, goet hi te ag gre ga tes show a bla ck in ner pa rt (bla ck goet hi te co re), sur roun ded by the brown goet hi te wit hout xrd de tec tab le in clu sio ns (brown goet hi te man tle). the textu ral type 2 (fig. 3b) com pri ses brown goet hi te ag gre ga te [plus a mi nor quan ti ty of sub mic ros co pic quar tz] fi l lin gs of mic ro frac tu res in si de the ho st li mes to ne. al thou gh si mi lar to the pre vious type 2, the textu ral type 3 (fig. 3c) is cha rac te ri sed by an ad mixtu re of the vir tual waxy quar tz im preg na tio ns alo ng the ho st li mes to ne bed di ng pla nes. fi gu re 1: map of the ad ria tic sea and sur roun di ng main la nd showi ng the lo ca tion of goet hi te mi ne ra li za tion on du gi otok. dof = du gi otok fau lt; iaf = in ter nal ad ria tic frac tu re (geop hysi cal ano ma lies ac cor di ng to brdarević & oluić, 1979 and košćec, 1986) fi gu re 2: pho tog rap hy of an out crop of goet hi te mi ne ra li za tion at br bin šći ca co ve, in fi l li ng the system of in ter bed di ng pla nes (a) and sub ver ti cal tec to nic cre vi ces (b) in the ho st up per cre ta ceous li mes to ne from the shal low sea and hi gh-ti dal zo ne. the oc cur ren ce com pri ses goet hi te mi ne ra li za tion of textu ral type 1. fi gu re 3: pho tog rap hs of ha nd spe ci me ns of goet hi te mi ne ra li za tion of textu ral type 1 (a), textu ral type 2 (b) and textu ral type 3 (c). on textu ral type 3 com ple te ly ge ne tic and tem po ral in de pen de nt to do ro ki te mi ne ra li sa tion is ob ser ved whi ch is the sub je ct of anot her pa per (lugović et al., 2008). for goet hi te mi ne ra li za tion de tai ls see the text. 03 segovic.indd 2003 segovic.indd 20 26.6.2008 9:17:5426.6.2008 9:17:54 geologia croatica 21 bra ni mir šegvić: si-p im pu re al-goet hi te mi ne ra li za tion on the is la nd of du gi otok (cen tral ad ria tic, croa tia) 3. ana lyti cal methods sam ples rep re sen ti ng all three textu ral grou ps we re trea ted wi th ph 4.5 buf fe red naac/hac so lu tion to dis sol ve cal ci te and di sag gre ga te the goet hi te. brown and bla ck goet hi te of textu ral type 1 se pa ra ted as vir tual ly pu re frac tio ns by ha nd pic ki ng, usi ng a bi no cu lar mic ros co pe af ter crus hi ng the com po si te sam ple. the xrd ana lyses of powde red se pa ra tes from the goethi te mi ne ra li za tion textu ral types 1 and 2 we re per for med at the fa cul ty of mi ni ng, geo lo gy and pet ro leum en gi nee ri ng, uni ver si ty of zag reb, usi ng a phil li ps dif frac to me ter 1820 and cukα ra dia tion, grap hi tic mo noc hro ma tor (u = 40 kv, i = 35 ma). the sam ples we re scan ned at a ra te of 0.5°/min over the ran ge of 2–70° 2θ. the mi ne ral pha ses we re iden ti fi ed usi ng the powder dif frac tion fi le (1996)(*) da ta system (goet hi te – jcpdf car ds num ber 00-029-0713; cal ci te – jcpdf car ds num ber 00-005-0586; quar tz – jcpdf car ds num ber 00-0050490). the xrd ana lyses of textu ral type 3 we re do ne at the fa cul ty of scien ce, uni ver si ty of zag reb usi ng a phil li ps dif frac to me ter x’pert pro (u = 45 kv, i = 40 ma). the sam ples we re scan ned at the ra te of 2°/min over the ran ge of 4–64° 2θ and the dif frac tion pat ter ns we re iden ti fi ed usi ng the jcpds system da ta ba se (quar tz – jcpdf car ds num ber 00-046-1045). the che mi cal com po si tion of goet hi te from textu ral types 1 and 2 was mea su red by sem eds and epma at the mi nera lo gi cal in sti tu te of the rup rec ht-kar ls uni ver si ty of hei delbe rg usi ng the cameca sx51 elec tron mic rop ro be equip ped wi th fi ve wa ve len gth-dis per si ve spec tro me te rs. ope ra ti ng pa rame te rs we re 15 kv ac ce le ra ti ng vol ta ge, 20 na beam cur re nt, ~1 µm beam si ze and 10 s coun ti ng ti me for all ele men ts. na tural mi ne ra ls, oxi des (co run dum, spi nel, haema ti te and ru ti le) and si li ca tes (al bi te, or thoc la se, anor thi te and wol las to ni te) we re used for ca lib ra tion. raw da ta for all ana lyses we re cor rec ted for mat rix ef fec ts wi th the pap al go rit hm (pouchou & pichoir, 1984, 1985) im ple men ted by cameca. for mu lae cal cu la tio ns we re do ne usi ng a sof twa re pac ka ge de sig ned by ha ns-pe ter meyer (mi ne ra lo gi cal in stitu te of the rup rec ht-kar ls uni ver si ty of hei del be rg). 4. results 4.1. xrd mi ne ra lo gy goet hi te of textu ral type 1 cha rac te ri zes stro ng pea ks at 4.1698 å, 2.4499 å and 1.7195 å for bla ck ag gre ga te, and 4.1730 å, 2.4469 å and 1.7166 å for brown aggre ga te (tab le 1). the xrd pat ter ns of bo th ag gre ga tes sug ge st re la ti ve ly hi gh crystal li ni ty, par ti cu lar ly that of the bla ck va rie ty. quar tz was iden ti fi ed as the mixi ng pha se wit hin the bla ck ag gre ga te, whe reas the xrd pat te rn of the brown ag gre ga te iden ti fi ed only goet hi te. unit ce ll crystal log rap hic pa ra me te rs for brown and bla ck goet hi te from the mi ne ra li za tion textu ral type 1 are dis played in tab le 2. the b axis di men sio ns are al mo st iden tical whi le the a and c axes of bla ck goet hi te, i.e. al-sub sti tu ted va rie ty (see be low), are slig htly lar ger re sul ti ng in its lar ger unit ce ll vo lu me. sin ce al3+ is smal ler than fe3+ the se da ta ap pear crystalloc he mi cal ly il lo gi cal and wi ll be re vi si ted in the dis cus sion. goet hi te of textu ral types 2 and 3 is cha rac te ri zed by stro ng pea ks at 4.176 å, 2.444 å, 1.717 å and 4.915 å, 2.577 å, 1.720 å res pec ti ve ly. quar tz is a mixi ng pha se in bo th types as we ll as mno·oh in the textu ral type 3. 4.2. epma and sem mi ne ra lo gy and che mis try scan ni ng elec tron mic ros co pe (sem) ob ser va tio ns (fi gs 4a and 5) re vea led that goet hi te mi ne ra li za tion of textu ral type 1 com pri ses a he te ro ge neous co re, wi th va rious em bed ded pet roge ne tic mi ne ra ls (bla ck goet hi te), and a ho mo ge nous man tle con si sting of goet hi te free of vir tual in clu sio ns (brown goethi te). k-fel dspar (or91.4–94.9ab5.1–8.4), al man di ne-ri ch me ta morphic gar net (py9.7alm62.5sp5.0and4.5gro17.9), cal ci te, quar tz and (*) jcpdf in ter na tio nal cen ter for dif frac tion da ta (1996) table 1 va lues for d-spa ci ng (d/å) and in ten si ty (i/%) for the re fe re nt goet hi te and for brown and bla ck goet hi te from the du gi otok mi ne ra li zation textu ral type 1 hin dlow. uk (00-029-0713) sam ple do-1d brown goet hi te sam ple do-1c bla ck goet hi te d i dhkl ihkl dhkl ihkl 4.9800 12 4.9661 14 4.9599 12 4.1830 100 4.1730 100 4.1698 100 3.3830 10 3.3799 16 3.3749 9 2.6930 35 2.6900 40 2.6899 27 2.5270 4 2.5219 5 2.5212 8 2.4890 10 2.4857 8 2.4863 9 2.4500 50 2.4469 63 2.4449 39 2.2530 14 2.2498 14 2.2499 7 2.1900 18 2.1836 15 2.1876 14 2.0890 1 2.0078 3 2.0888 3 1.9200 5 1.9176 6 1.9172 3 1.7728 1 1.7166 21 1.7196 20 1.5637 10 1.5638 10 1.5649 10 1.4541 5 1.4536 11 1.4552 7 table 2 crysta log rap hic pa ra me te rs of the brown and bla ck goet hi te of the du gi otok mi ne ra li za tion textu ral type 1 ce ll pa ra me te rs brown (do-id) bla ck (do-ic) a (å) 4.609(1) 4.616(2) b (å) 9.961(2) 9.963(3) c (å) 3.015(8) 3.022(1) vo lu me 138.44(5) 138.99(6) 03 segovic.indd 2103 segovic.indd 21 24.6.2008 11:06:2724.6.2008 11:06:27 geologia croatica geologia croatica 61/1 22 ru ti le we re iden ti fi ed amon gst the inclu sio ns in the bla ck goethi te (fig. 4b). textu ral type 2 goet hi te showed no su ch re gula ri ties in the sen se of struc tu ral and che mi cal di su ni ty. al thou gh the epma mea su re men ts we re per for med usi ng a hig hly fo cu sed beam (~1 µm), all goet hi te ana lyses ap pear to be con ta mi na ted by ac ces so ry pha ses, par ti cu lar ly quar tz (tab le 3). howe ver, the mea su red che mi cal com po si tio ns from the bla ck and brown seg men ts of type 1 mi ne ra li za tion are clear ly dis tin guis hed in the fe2o3/(fe2o3+al2o3) vs. fe2o3 plot (fig. 6). the ma jo ri ty of the ana lyses from the bla ck seg me nt fo rm a nar row com po si tio nal fi e ld (70–76 wt % fe2o3, fe-al ra tio 0.91–0.94), and clo sely rep re se nt the com posi tion of al-sub sti tu ted, i.e. bla ck goet hi te. brown man tle goethi te shows com pa ra ti ve ly low al2o3 and sio2 (tab le 3) and wi th the fe2o3/(fe2o3+al2o3) ra tio of ~ 1 re sem bles the stoichiomet ric com po si tion. the dis cre te knob by va rie ties it se lf show si mi lar po la ri zed com po si tio ns in de pen de nt of the textural po si tion of the ana lyzed spo ts (fig. 6). ran dom sem eds ana lyses of goet hi te of textu ral type 1 are dis played in fig. 7 as four ma jor cor re la tion tren ds. the cor re la tion diag ram al2o3-sio2 (fig. 7a) de pic ts the po si ti ve cor re la tion of si li ca wi th al, i.e. it con strai ns si li ca exclu si ve ly alo ng wi th the al-goet hi te in the bla ck co res (r2=0.69). the es tab lis hed al2o3-sio2 cor re la tion is plot ted again st the fe2o3, mgo and p2o5 (fi gs. 7b–7d) abun dan ces. a nega ti ve fe2o3 cor re la tion in res pe ct to the al2o3-sio2 (r2=0.52) (fig. 7b) amou nt shows the wa ne of goet hi te fe con te nt towar ds the mi ne ral co re. a posi ti ve mgo cor re la tion in res pe ct to the al2o3-sio2 amou nt (r2=0.37) (fig. 7c) cor ro bo ra tes an amou nt of crypto-crystal li ne si li ca te pha ses in the goet hi te co re. sem eds ana lyses re vea led unu sual ly hi gh p2o5 con cen tra tion in the ana lyzed goet hi te (up to 2.8 wt %, fig. 7d). hig her phospho rus va lues are as so cia ted wi th hi gh fe2o3 values (80–100 wt %) sug ges ti ng its com po si tio nal en ric hme nt in the goet hi te bla ck co re ag gre ga tes. 5. discussion 5.1. mi ne ra li za tion as sem bla ge and goet hi te che mis try due to the slow goet hi te growth, the ana lysed mi ne ra lization con si sts of nu me rous me dium to hi gh crystal li ni ty sub mic roso pic goet hi te crystal li tes. the mi ne ra li za tion is com po sed al mo st en ti re ly of goet hi te. im pu ri ties wit hin goet hi te (e special ly bla ck goet hi te of textu ral type 1), com pri se si li ca te pha ses (quar tz, k-fel dspar, me ta mor phic gar net and ru ti le) and cal ci te. howe ver, apa rt from coar se cal ci te and ubiqui tous quar tz, their amou nt is always be low the xrd de tec tion li mit (~5 wt %). it is known that quar tz and p, (in the fo rm of po4 3–), bi nd to the reac ti ve pla ces of goet hi te ter mi nal fa ces and do not en ter the crystal struc tu re (glasauer et al., 1999; parfitt, 1979, 1989). in synthe tic goet hi te, si li ca is con strai ned to be ad sor bed on sur fa ces and lo ca ted wit hin the po res be tween struc tu ral do mai ns (fisher, 1999; glasauer et al., 1999). fi gu re 4: a. sem ima ge ry of goet hi te mi ne ra li za tion textu ral type 1 showi ng the lo ca tion of the epma wds mea su red com po si tio nal pro fi le. bla ck goet hi te in the co re (grey) in clu des va rious mi ne ral im pu ri ties. clean brown goet hi te (brig ht) for ms a man tle arou nd the bla ck goet hi te. b. bse ima ge ry of goet hi te mi ne ra li za tion textu ral type 1. kfs = k-fel dspar, grt = gar net, rt = ru ti le, qtz = quar tz and cc = cal ci te in clu sio ns. fi gu re 5: sem ima ge ry of goet hi te mi ne ra li za tion type 1 showi ng in mo re de tail the re la tio nshi ps from fi gs. 4a and b. bla ck goet hi te (lig ht grey) exhi bi ts va rious si li ca te mi ne ral in clu sio ns (bla ck spo ts). clean brown goet hi te (da rk) for ms a rim arou nd the bla ck goet hi te. 03 segovic.indd 2203 segovic.indd 22 24.6.2008 11:06:2824.6.2008 11:06:28 geologia croatica 23 bra ni mir šegvić: si-p im pu re al-goet hi te mi ne ra li za tion on the is la nd of du gi otok (cen tral ad ria tic, croa tia) this va rie ty is col loquial ly na med si-goet hi te. we pro po se to avoid this na me sin ce si li ca is not struc tu red in to the goet hi te ce ll. in the ba sic and slig htly acid en vi ron me nt, phos pha te wil lin gly ma kes com plexes wi th fe3+ de pen di ng on reac ti ve sur fa ce feo·oh grou ps and the crystal li ni ty of the oxi de. the reac tion pro bab ly in vol ves a rapid, stro ng li ga nd exchan ge, fol lowed by wea ker li ga nd exchan ge and phos pha te pe net ration at de fe ctive si tes and po res (parfitt, 1989). the re fo re, the ran dom phos pho rus con te nt of ana lysed bla ck goet hi te (fig. 7d) refl ec ts its com plex po ro si ty. the measu red goet hi te che mi cal com po si tion was in fl uenced by the che mis try of ir ra dia ted sub mic ro nic im pu ri ties, cau si ng a sig ni fi ca nt num ber of ana lyses to be con ta mi na ted (fig. 6, fe203 < 70 wt %). resul ts wi th fe2o3 > 70 wt % may be ac cep ted as the lea st con ta mi na ted or even un con ta mi na ted (fe2o3 > 80 wt %). the re sul ts be tween 70 and 76 wt % fe2o3 ob tai ned for bla ck goet hi te co res of textu ral type 1 show a hi gh abun dan ce of al, (tab le 3, fig. 6) and si, whi ch is mos tly al lo ca ted to quar tz. the amou nt of al can not be stoic hio metrically com bi ned wi th ot her ana lyzed ca tio ns to yie ld any known (si li ca te) mi ne ral pha se. sin ce al (oxy)hydroxi des are exclu ded as pos sib le pa ra ge ne tic mi ne rals, we pre su me that al is sub sti tu ted for fe in the goet hi te ag gre ga ted bla ck co re of the textu ral type 1, (fig. 6, fe2o3/(al2o3+fe2o3) ra tio va ries from 0.90 to 0.95). goet hi te from the brown man tle of the same textu ral type is al poor (fig. 6, fe2o3/(al2o3+fe2o3) ra tio ~1), and re sem bles a near stoic hio met ric com po si tion. in na tu ral goet hi te, fe3+ is rea di ly sub sti tu ted by al oc casio nal ly reac hi ng up to 0.33 mo le frac tion (e.g. fitzpatrick & schwertmann, 1982; tardy & nahon, 1985; fabris et al., 1986; carlson, 1995). the deg ree of sub stitu tion of al for fe is one of the pa ra me te rs fa vou ri ng hi gh p abun dan ce in goet hi te (ainsworth & sumner, 1985). al sub sti tu ted goet hi te from the ana lysed goet hi te mi ne ra li zation stron gly sup por ts this sta te me nt by a po si ti ve cor re la tion of p and al abun dan ces (fig. 7d). refer ri ng to the unit ce ll pa ra me ter con tra dic tion, i.e. lar ger ce ll vo lu me of al-sub sti tu ted goet hi te (bla ck goet hi te) com pa red to the stoic hio met ric goet hi te (brown goet hi te), the phe no me non can be explai ned wi th ran dom al-sub sti tu tion as a plau sib le cau se of this crystalloc he mi cal dis cre pan cy. investi ga tio ns of al-sub sti tu ted goet hi te pre ci pi ta ted at re la ti ve ly table 3 se lec ted mic rop ro be spot ana lyses (in wt.%) of the du gi otok goet hi te mi ne ra li za tion mi ne ra li za tion type ic ic im im ii ii iii iii ana lyses no. 9a 27 02 17 01 04 04b 02a sio2 7.54 11.31 1.79 1.68 6.49 2.34 6.42 15.36 tio2 0.17 0.31 0.00 0.00 0.05 0.02 0.09 0.35 al2o3 5.97 11.46 0.04 0.05 4.77 0.00 4.59 9.12 cr2o3 0.00 0.02 0.00 0.00 0.02 0.00 0.02 0.04 fe2o3 71.22 60.59 81.12 81.08 71.57 78.26 72.59 58.36 mno 0.00 0.06 0.08 0.03 0.06 0.03 0.14 0.12 mgo 0.55 0.48 0.12 0.18 0.99 0.09 0.76 1.46 cao 0.25 0.21 0.33 0.36 0.38 0.34 0.52 0.82 na2o 0.16 0.20 0.05 0.02 0.21 0.10 0.12 0.18 k2o 0.42 0.13 0.02 0.00 0.19 0.01 0.52 1.88 to tal 86.29 84.77 83.55 83.40 84.73 81.19 85.77 87.69 al sub st. (mol. %) 13.10 29.60 0.10 0.10 10.40 0.00 9.90 24.50 � mi ne ra li za tion types i, ii and iii mat ch diff e re nt textu ral types (see text for de tail in for ma tion). � c=co re, m=man tle of the goet hi te ap pea ran ce from the textu ral type 1. � al sub st. (mol. %) cor res pon ds to goet hi te for mu la cal cu la ted on the ba sis of 1.5 oxygen and 1.0 to tal ca tion af ter sub trac tion of sio2 and al ka lies from the epma poi nt ana lyses. fi gu re 6: plot of fe2o3/(fe2o3+al2o3) ver sus fe2o3 for epma wds spot ana lyses of goet hi te mi ne ra li za tion from all three textu ral types. in the mi ne ra li za tion of textu ral type 1, three diff e re nt com po si tio ns are clear ly dis tin guis hed: sio2 + si li ca pha ses hig hly mixed com po si tion and alsub sti tu ted com po si tion (vir tual ly goet hi te) and near stoi chiomet ric goet hi te (vir tual brown goet hi te). the other two textu ral types show si mi lar com po si tio nal re la tio ns. 03 segovic.indd 2303 segovic.indd 23 24.6.2008 11:06:3024.6.2008 11:06:30 geologia croatica geologia croatica 61/1 24 low tem pe ra tu res, al so indi ca te that unit ce ll pa ra me te rs in crea se wi th dec rea si ng synthe sis tem pe ra tu re (cornell & schwertmann, 2003). this re la tion ship is at tri bu ted to the incor po ra tion of struc tu ral oh in the goet hi te lat ti ce whi ch aug men ts in crea si ng al-sub sti tu tion (schwertmann et al., 1985). 5.2. che mi cal con straints of goet hi te for ma tion goet hi te is a com mon and abun da nt con sti tue nt of ma ny se conda ry iron ore de po si ts and va rious types of soi ls, par ti cu lar ly of ter ra ros sa (durn et al., 1999). for ma tion of the se pro duc ts is stron gly con trol led by weat he ri ng, i.e. by des cen di ng so lutio ns. su ch goet hi te-bea ri ng oc cur ren ces com pri se leac hi ng of fe from a pri ma ry sub stra te and mo bi li sa tion in the fo rm of fer ri hydri te (singer et al., 1998). la ter, goet hi te is for med di rec tly by the tran sfor ma tion of fer ri hydri te and/or even tual ly via hae ma ti te in an as sem bla ge al so con sis ti ng of al-hydra ted oxi des and clay mi ne ra ls as the pro duc ts of in com ple te la te riti za tion (tardy & nahon, 1985). an as sem bla ge for med fol lowi ng this ge ne tic pat te rn shows typi cal col lo mor phban ded textu re, poor crystal li ni ty of all pha ses and pu re ly alsub sti tu ted goet hi te. in con tra st, goet hi te from the ana lysed mi ne ra li za tion is we ll crystal li zed and may show excep tio nal ly coar se ag gre gates (fig. 3a). ear ly crystal li zed al-sub sti tu ted goet hi te em be ds k-fel dspar, al man di ne-ri ch me ta mor phic gar net, cal ci te, quar tz and ru ti le and is fol lowed by al mo st pu re goet hi te (fig. 4). this na tu ral ca se sup por ts the re sul ts of ther mo dyna mic experi men ts whi ch show that the ra te of al-sub sti tu tion in goet hi te is stron gly de pen de nt on the avai la bi li ty of al and the che mistry of as so cia ted mi ne ra ls (tardy & nahon, 1985). the al-substituted goethite (black goethite) from dugi otok is characterized by 13.1–29.6 mol % of al (table 3, fig. 6), and high amounts of silica impurities and bonded phosphate. silica binds to the goethite terminal faces suppressing the growth rate and consequently enhances its crystallinity (cornell & giovanoli, 1990). the adsorption of silica is minimal at low ph due to formation of protonated or neutral silica polymers which make a stable feosi(oh)3 2+ complex (weber & stumm,1965). at ph values between 8 and 11, goethite forms at the expense of hydrolyzed fe(oh)4 −, whereas silica interferes either by hindering nucleation and crystal growth of goethite or by reacting with metastable ferrihydrite, thus retarding the supply to growing units (glasauer et al., 1999). phosphate enrols the goethite surface rapidly with strong ligand exchange both at the surface and at defect sites and pores. the rate of goethite formation is greatly reduced in the presence of phosphate, due to an increase in the entropic component of the free energy of activation. analogous to the silica effect, the overall goethite crystallinity is enhanced due to the slower crystal growth (shaw et al., 2005). the en han ced crystal li ni ty of goet hi te com po si tio nal types, the com po si tion of al-sub sti tu ted goet hi te wi th si li ca su b-mic ro do mai ns, the pre sen ce of p but la ck of fe-phos pha te and stab le, coar se grai ned cal ci te in the pa ra ge ne sis stron gly sug ge sts al ka li ne con di tio ns of for ma tion. the re fo re, for mation of du gi otok goet hi te mi ne ra li za tion di rec tly lin ked to kar sti fi ca tion cou ld ha ve been exclu ded sin ce kar sti fi ca tion fi gu re 7: ma jor ele me nt (a ll in wt.%) cor re la tion diag ra ms of sem eds spot ana lyses from goet hi te mi ne ra li za tion type 1. no te the almo st stoi chiometric com po si tion of goet hi te from the brown man tle (ar row). a) al2o3 vs. sio2 diag ram showi ng a po si ti ve cor re la tion. b) feo vs. (sio2+al2o3) diag ram showi ng a ne ga ti ve cor re la tion. c) mgo vs. (sio2+al2o3) showi ng a slig ht po si ti ve cor re la tion. d) p2o5 vs. (sio2+al2o3) showi ng a slig ht po si ti ve cor re la tion. 03 segovic.indd 2403 segovic.indd 24 24.6.2008 11:06:3124.6.2008 11:06:31 geologia croatica 25 bra ni mir šegvić: si-p im pu re al-goet hi te mi ne ra li za tion on the is la nd of du gi otok (cen tral ad ria tic, croa tia) fa vou rs an acid en vi ron me nt. this sta te me nt is cor ro bo ra ted wi th the mo de of mi ne ra li za tion oc cur ren ce ob ser ved at the out cro ps. 5.3. geo tec to nic en vi ron me nt of goet hi te mi ne ra li za tion simi lar goet hi te mi ne ra li za tion of po st eo ce ne age was re ported near no vi vi no dol ski and on the is lan ds of krk and cres si tua ted so me 125 km nnw from du gi otok (fig. 1) (mar ković, 2002) sug ges ti ng that the in ves ti ga ted goet hi te mi ne ra li za tion shou ld be con si de red on the re gio nal sca le of the nor th ad ria tic. the pre se nt sur fa ce lit ho lo gy of du gi otok does not of fer any sub stra tum from whi ch fe, al, si and p may ha ve been de ri ved. hen ce, we pos tu la te their sour ce as bei ng in the sub mer ged ad ria tic cru st. there is a hi gh po si ti ve gra vi met ric ano ma ly si tua ted la nd-wa rd of du gi otok, (košćec, 1986). fur ther mo re, se ve ral geo mag ne tic ano ma lies are lo ca ted seawa rd of the is la nd (brdarević & oluić, 1979). all cou ld be as sig ned to ig neous roc ks, al thou gh ig neous ma teria ls we re not pro ven (fig. 1). howe ver, ul tra-al ka li ne in trapla te vol ca nic roc ks da ted to the plio ce ne we re re cog ni zed in se ve ral co res dril led in the dep res sion of du gi otok (miletić & lugović, 2000). the ig neous oc cur ren ces tra ce the sou th eas te rn seg me nt of the schio fau lt system whi ch con ti nuous ly stret ches nw-se from vi cen za to pa lag ru ža (grandić et al., 1997). the du gi otok fau lt (dof), be lon gs to this fau lt system (fig. 1), and tra ces a lithos phe ric frac tu re (in ter nal ad ria tic frac tu re – iaf) wit hin the ad ria mic rop la te (oldow et al., 2002). the schio fau lt system cau sed ma jor ver ti cal dis pla ce men ts in the ad ria tic cru st and is tran sec ted by dextral stri ke slip w-e tren di ng li tos phe ric faul ts (di bucci & mazzoli, 2003). bo th fau lt syste ms we re reac ti va ted du ri ng the plio ce ne (5–2 ma bp) on ac cou nt of an ancie nt struc tu ral weak ne ss in the ad ria tic cru st. mag ma tic oc cur ren ces are lo cated at or near the in ter sec tio ns of the se fau lt syste ms (fig. 1). we li nk the du gi otok goet hi te mi ne ra li za tion to the plio ce ne exten sio nal tec to nic ac ti vi ty whi ch pro du ced sub ma ri ne mag ma tic ac ti vi ty du ri ng an exten si ve ma ri ne tran sgres sion af ter the mio ce ne emer sion. the tem pe ra te as cen da nt pa ren tal so lu tions ri ch in fe2+, al, si and p, yie lded goet hi te mi ne ra liza tion, repre sen ti ng the af ter ma th of plio ce ne mag ma ti sm. 6. conclusions in our mo del, goet hi te crystal li zed from as cen da nt so lu tio ns, pro bab ly slig htly war med due to in crea sed hea th fl ux cau sed by plio ce ne ig neous ac ti vi ty. the fe2+, al, si and p ri ch so lutio ns to get her we re tec to ni cal ly mo bi li zed from a hid den feen ric hed me ta mor phic si li ca te sour ce, and ro se up throug hout the com plex sub mer ged cre vi ces for med by mio ce ne kar sti fi ca tion and plio ce ne tec to nic ac ti vi ty. it is li ke ly that du ri ng the up li ft, ve ry sma ll quan ti ties of the me ta mor phic sub stra te we re in clu ded in the so lu tion repre se nted by in com ple te dis solved si li ca te mi ne ra ls. ini tial crystal li za tion took pla ce un der hi gh oxygen fu ga ci ty, and slig htly ba sic ph, lea di ng to the fa st re mo val of al, si and p throu gh the pre ci pi ta tion of mixtu res com pri si ng al-sub sti tu ted goet hi te and quar tz wi th syntem poral de po si tion of sus pen ded me ta mor phic pha ses. the refo re, due to the com ple te re mo val of si li ca and al, the re si dual so lution crystal li zed as al mo st pu re, stoic hio met ric goet hi te. acknowledgment this pub li ca tion is the re su lt of con tri bu tion from the 0195025 and 195-1951126-3205 to bl and 0119420 to vb gran ts fo rm the croatian mi nis try of scien ce, edu ca tion and spor ts. than kful re gar ds go to r. al the rr and h.-p. meyer from the mi ne ra lo gi cal in sti tu te of the rup rec ht-kar ls uni ver si ty in hei del be rg, who pro vi ded the in strumen tal fa ci li ties. v. garašić and an ano nymous re viewer sig ni fi cantly im pro ved an ear ly ver sion of the ma nus cri pt. the aut ho rs are great ly in deb ted to g. du rn and g. si ja ric for their de tai led re view. we exte nd our ap pre cia tion to ž. ži go več ki go bac for her he lp du ri ng the xrd mea su re men ts and in ter pre ta tion as we ll as to n. če gec, b. pr ša and m. va le nt for their as sis tan ce in the la bo ra to ry. mrs. kras na panj ko ta pro vi ded us wi th her ki nd hos pi ta li ty du ri ng fi e ld wo rk. references: ainsworth, c. c. & sumner, m. e. (1985): ef fe ct of alu mi nium sub sti tu tion in goet hi te on phos pho rus ad sor ption. ii ra te of ad sorption. – soil scien ce so cie ty of ame ri ca jour nal, 49, 1149–1153. brdarević, n. & oluić, m. (1979): pri log poz na va nju tek ton ske gra đe jad ran skog pod mor ja [a con tri bu tion to un der stan di ng of the ad ria tic sea bed tec to ni cs – in croa tian]. – zbor nik rgn fa kul te ta u po vo du 40 go di na ra da (1939–1979), 318–332. carlson, l. (1995): alu mi nium sub sti tu tion in goet hi te in la ke ore. – bul le tin of the geo lo gi cal so cie ty of fin la nd, 67, 19–28. cornell, r. m. & giovanoli, r. (1990): tran sfor ma tion of aka ganei te in to goet hi te and hae ma ti te in al ka li ne me dia. – clays and clay mi ner., 38, 469–476. cornell, r. m. & schwertmann, u. (2003): the iron oxi des: struc tu re, pro per ties, seac tio ns, oc cu ren ces and uses, 2nd edn. – wiley-vch, wein heim, 664 p. di bucci, d. & mazzoli, s. (2003): the oc to be r-no vem ber 2002 mo li se seis mic sequen ce (sout he rn ita ly): an expres sion of ad ria in trap la te de for ma tion. – j. geol. soc., 160, 503–506. durn, g., ottner, f. & slovenec, d. (1999): clay mi ne ra ls as an in di ca tor of po lyge ne tic ori gin of ter ra ros sa in is tria, croa tia. – geo der ma, 91, 125–150. džaja, k. (2003): geo mor fo loš ke zna čaj ke du gog oto ka [geo mor pholo gic fea tu res of the du gi otok is la nd – in croa tian]. – geoad ria, 8/2, 5–44. fabris, j. d., resende, m., allan, j., & coey, j. m. d. (1986): mössbauer ana lysis of bra zi lian oxi so ls. – hyper fi ne in te rac tio ns, 29, 1093–1096. fisher, l. (1999): in ves ti ga tio ns of the as-/desorption and dif fu sion pro ces ses of hea vy me ta ls and alu mi nium wi th goet hi tes of dif fe rent crystal li ni ty – expe ri men tal re sul ts and pro ce ss mo del li ng. – ph.d. the sis, univ. of bo nn, 205 p. fitzpatrick, r. w. & schwertmann, u. (1982): al-sub sti tu ted goet hi te-an in di ca tor of pe do ge nic and ot her weat he ri ng en vi ronmen ts in sou th af ri ca. – geo der ma, 27, 335–347. glasauer, s., friedl, j. & schwertmann, u. (1999): pro perties of goet hi tes pre pa red un der aci dic and ba sic con di tio ns in the pre sen ce of si li ca te. – jour nal of col loid and in ter fa ce scien ce, 216, 106–115. 03 segovic.indd 2503 segovic.indd 25 24.6.2008 11:06:3124.6.2008 11:06:31 geologia croatica geologia croatica 61/1 26 grandić, s., boromisa-balaš, e. & šušterčić, m. (1997): explo ra tion con ce pt and cha rac te ris tic of the di na ri des stra tig raphic and struc tu ral mo del in the croa tian of fsho re area, pa rt 1. – nafta, 48, 117–128. košćec, b. (1986): prim je na da ljin skih me to da u naf tno geo loškim istraživa nji ma is tre i pod mor ja sje ve rois točnog jad ra na [the ap pli cation of re mo te sen si ng met ho ds in pet ro leum geo lo gy in ves ti ga tion of is tra and ne ad ria tic sea bed – in croa tian]. – ph.d. the sis, univ. of bel gra de, 277 p. lugović, b., šegvić, b. & šegvić, t (2008): mn-cru st to do ro ki te mi ne ra li za tion on sw bac ksho re cre ta ceous li mes to nes from the is la nd of du gi otok (cen tral ad ria tic, croa tia). – ac ta ad ria ti ca, 49, 55–64. marković, s. (2002): hr vat ske mi ne ral ne si ro vi ne. [croa tian mi neral re sour ces – in croa tian]. – hr vat. geol. in sti tut, zag reb, 544 p. miletić, d. & lugović, b. (2000): con tras ti ng ul traal ka li lit hoc lasts in plio ce ne se di men ta ry roc ks from the dep res sion of du gi otok is la nd, ad ria tic o ff-sho re (croa tia). – 2nd croat. geol. con gre ss abstra ct book (i. vla ho vić & r. biondić, eds.), hr vat. geol. in sti tut, zag reb, 327–331. oldow, j. s., ferranti, l., lewis, d. s., campbell, j. k., d’ argenio, b., catalano, r., pappone, g., carmignani, l., conti, p. & aiken, c. l. v. (2002): ac ti ve frag men ta tion of ad ria, the nor th af ri can pro mon to ry, cen tral me di ter ra nean oro gen. – geo lo gy, 30, 779–782. parfitt, r. l. (1979): the avai la bi li ty of p from phos pha te-goet hi te brid gi ng com plexes. de sor ption and up ta ke by ryeg ra ss – pla nt and soil, 53, 55–65. parfitt, r. l. (1989): phos pha te reac tio ns wi th na tu ral al lop ho ne, ferri hydri te and goet hi te. – jour nal of soil scien ce, 40, 359–369. pouchou, j. l. & pichoir, f. (1984): a new mo del for quan ti ta ti ve ana lyses. i. ap pli ca tion to the ana lysis of ho mo ge neous sam ples. – la rec her che aéros pa tia le, 3, 13–38. pouchou, j. l. & pichoir, f. (1985): »pap« (ϕ−ρ−ζ) cor rec tion pro ce du re for im pro ved quan ti ta ti ve mic roa na lysis. – mic ro beam ana lysis (j. t. ar mstro ng eds.), san fran cis co pre ss, 104–106. schwertmann, u., cambier, p. & murad, e. (1985): pro perties of goet hi tes of va ryi ng crystal li ni ty. – clays and clay mi ner., 33, 369–378. shaw, s., pepper, s., bryan, n. d. & livens. f. (2005): the kine ti cs and mec ha nis ms of goet hi te and he ma ti te crystal li za tion under al ka li ne con di tio ns, and in the pre sen ce of phos pha te. – am. mi ner., 90, 1852–1860. singer, a., schwertmann, u. & friedl, j. (1998): iron oxi de mi ne ra lo gy of ter re ros se and ren dzi nas in re la tion to their mois ture and tem pe ra tu re re gi mes. – eur. jour. of soil sci., 49, 385–395. tardy, y. & nahon, d. (1985): geoc he mis try of the la te ri tes, sta bili ty of al-goet hi te, al-he ma ti te, and fe3+-kao li ni te in bauxi tes and fer ric re tes: an ap proa ch to the mec ha ni sm of con cre tion for ma tion. – am. j. sci., 285, 865–903. weber, w. j. & stumm, w. (1965): for ma tion of a si li ca to-i ron (iii) com plex in di lu te aqueous so lu tion. – jour nal of inor ga nic and nuclear che mis try, 27, 237–239. manuscript received june 6, 2007. revised manuscipt accepted january 18, 2008. 03 segovic.indd 2603 segovic.indd 26 24.6.2008 11:06:3224.6.2008 11:06:32 chronohorizons based on resistivity curve variations upper miocene sediments of the ivaniê grad formation in the sava depression (nw croatia) boris vrbanac 1. introduction regionally recognisable sections of motifs (sequences of equally developed peaks) on resistivity curves of wells drilled in the croatian part of the pannonian basin system were as early as the 1960’s (e.g. ©imon, 1963, 1970, 1973; pletikapi∆, 1965). in well intervals composed of marls, the ek-markers within these motifs were placed on the characteristic points of resistivity curves that were best traced over almost the entire area of the croatian part of the pannonian basin. these ek-markers enabled regional correlation of the sediments, using the markers to construct a framework of lithostratigraphic subdivisions. however, a more comprehensive explanation of what the ek-markers actually indicate was omitted. are they thin layers of specific characteristics, or is it a certain physical property of marls that produces these regionally recognizable motifs composed of resistivity peaks? a third possibility is that they reflect sequence surfaces of some kind. ©imon (1980) stated that: “their proved regional uniformity and stability gave them the characteristic of chronohorizons, ...”. in a more recent, unpublished report (banks et al., 19901) the markers are treated as facies boundaries. in order to define a depositional model for the ivaniê grad formation in the sava depression, the first task was to resolve the nature of the resistivity curve motifs, i.e. to establish the reasons for their repetition, thus also facilitating definition of the stratigraphic meaning of the ek-markers. 2. geologic framework the sava depression is the southernmost part of the pannonian basin system. it extends in a nw-se direction, around 90 km in length and 25 km in width (fig. 1). the ivaniê grad formation comprises part of the geologia croatica 55/1 11 23 10 figs. zagreb 2002 key words: resistivity curve, chronohorizons, single cycle, upper miocene, ivaniê grad formation, sava depression, croatia. ina naftaplin, exploration department, ©ubiêeva 29, hr-10000 zagreb, croatia. e-mail: boris.vrbanac@ina.hr abstract regional definition of chronohorizons represents a fundamental and most difficult problem in geology. adequate precision of dating can only be obtained from biological evolution, radioactive decay and from the key surfaces of the sequence stratigraphic concept (mfs, tse, and lse). it is concluded in this paper that the variation of formation resistivity values (ra curve), as measured in wells located in the croatian part of the pannonian basin system, is also a criterion for the stratigraphic definition of concurrently deposited sediments. this enables the construction of a sequence of lithogenetic units relat ed to very small time-intervals. the morphology of the resistivity curve measured in well sections composed of massive marls (that were deposited in a quiet environment of moderate water depth), is regionally exceptionally well defined. this pattern consists of a succession of peaks of lower and higher resistivity values that are in the same relative position regionally, which results in similar form of the resistivity curves of the wells in the study area. on the curve, one peak of higher values together with the next (overlying) peak of lower ones composes a single cycle (sc). marls of a single cycle were regionally deposited at the same time, thus enabling the points of both the maximal and minimal resistivity values of each sc to be considered as time-markers (chronohorizons). variation of the resistivity reflects fine changes of petrographic and granulometric composition which can be associated with cyclic water-level fluctuations (milankovitch cycles). for future exploration of the remaining, potential hydrocarbon accumulations in the sandstone reservoirs of the ivaniê grad formation in the sava depression, spatial modelling of the distribution, geometry, facies and palaeocurrent structure of separated depositional episodes and genetic units is suggested. this should be done with special emphasis on the spatial definition of channel sandstones that are the most important hydrocarbon reservoirs (according to current interpretations). 1 banks, n.l., cornford, c. & tubb, s. (1990): pannonian basin (phase ii final report).unpublished report, ina-naftaplin ecl (world bank project), fsd ina-naftaplin, zagreb. 12 geologia croatica 55/1 neogene clastic sedimentary complex and is composed of a sequence of sandstone, marl and siltstone layers. the approximate age of the sediments of this formation is late pannonian (late miocene). in the deepest parts of the depression the neogene complex is more then 5,000 m thick. the basement consists of metamorphic, eruptive and clastic palaeozoic rocks (pandæi∆, 1980; najdenovski et al., 1983). in the marginal parts of the depression, the thickness of the ivaniê grad formation ranges from 150-250 m, and it is almost exclusively composed of marls. in the central parts, where marls are interbedded with sandstone and siltstone layers, the total thickness occasionally reaches 800 m. in accordance with the sedimentological characteristics of the cored material (lithology, bedding, sedimentary structures, sand/shale ratio), the geometry of sandstone bodies and interpretation of the well-logs, the explored formation was found to be composed of hemipelagic muds and sediments of turbidite origin (vrbanac, 1996). the following facies were determined: massive marls facies (f1), thick-bedded to massive sandstones (f2), thin-bedded sandstones (f3) and facies of thin-bedded sandstones, siltstones and marls ( f4). hemipelagic muds are represented by massive marl facies (f1). the massive marls facies (f1) is located in whole parts of the sedimentary basin. the f2f4 turbidite facies are exclusively located in the central part of the depression, where they form an elongated sedimentary body that extends over 90 km in length, and is up to 15 km wide. in a ne direction, the sava depositional basin was separated from the drava basin by a submerged tectonically uplifted ridge. towards the east, the sandstone sedimentary bodies thin out when reaching the uplifted tectonic block that connected mt. psunj with mt. prosara (fig. 1). in spite of the fact that the upper pannonian marls crop out in the banovina region, south of the sava depression, the contemporary extension of the depositional basin in this direction can only be supposed. furthermore, the general mechanism fig. 1 location map of the studied area. of infilling can be regarded as aggradational, although smaller progradational and retrogradational phases have been identified by the detailed mapping of sandstone bodies within the lithostratigraphic members (the iva and okoli sandstones, respectively). the progradational phases are interpreted as periods when sandstone bodies gradually spread more and more from nnw to ese, while the retrogradational ones pertain to periods of sandstone retreat in a nw direction (vrbanac, 1996). 3. resistivity curve analysis comparison between the core material and resistivity curves leads to the conclusion that the regionally recognisable motifs on the resistivity curve are exclusively connected with the massive marls facies (f1). this facies is composed of homogeneous and massive, most ly unstratified marls. occasional traces of stratification are mostly observed through a change of colour or by the occasional thin interbed of siltstone or sandstone. the observed homogeneous appearance and petrographic composition of massive marls still results in variation of certain physical properties that are reflected in a succession of characteristic peaks on the resistivity curve. these peaks represent 1-3 m thick packages of marls, and their sequence, with major or minor variations, forms the regionally recognizable structure both in the marginal and central parts of depression. the resistivity curves of the wells in the marginal parts of the depression (fig. 1) clearly illustrate the identical motifs of peaks in all of the wells, as shown in figs. 2 and 3. selected peaks are connected by dotted lines in order to facilitate the correlation of shapes within the intervals. it can be observed that each and every one of the peaks on one curve has a corresponding peak on other curves, thus making a characteristic succession of peaks with identical shape and relationship to preceding and succeeding peaks. in this way, the sequence of peaks identify and characterise shape of the resistivity curve. the amplitude of peaks is not always the same, which means that they are not equally well marked in all of the wells, but most importantly they do exist. their constant shape and relative relationships between peaks that laterally remain unchanged are also important. so, the marginal parts of depression are exclusively composed of the massive marls that have a regionally identical structure of peaks on the resistivity curve. in order to illustrate the almost ideal sequence of the regionally recognizable peaks, a type-curve was constructed (fig. 4) by amalgamating of the resistivity curves measured in two wells (o-135 and hra-2). an overview of the resistivity curves from the wells located in the central part of the depression resulted in the interpretation of three turbidite facies, mostly represented by sandstone bodies, being interlayered with the massive marls that are identified by the characteristic peaks (figs. 5-8). these peaks allow the massive marls to be distinguished from the marl that was deposited from the tail of the turbidity current. a similar situation can be observed on the resistivity curves of 1700 wells in the central part of the depression, whereby the location of the well in the depression roughly defines which of the peak sequences of massive marls will be more pronounced. it is imperative to explain the cause of the observed regularity of peak structure on the resistivity curve in the massive marls intervals. let us analyse the factors that influence the shape of resistivity curves and the vertical change of the resistiv13vrbanac: chronohorizons based on resistivity curve variations... fig. 2 the identical structure of peaks on the resistivity curve (ra) within the massive marls facies association. the chosen logs are from the wells located in the marginal parts of the sava depression where the facies of massive marls is exclusively developed. the interval between the ek-markers rs5 and rρ is shown (f fault). 14 geologia croatica 55/1 ity of clastic sediments. the first group of factors consists of the ones that are preconditions in order to measure the quality of the resistivity curve. for instance, the well should be of either the nominal or a slightly greater diameter, the degree of the mud infiltration into the formation should be minimal, etc. factors determining the average resistivity of a formation or lithological member are located in the second group. the following can be quoted: formation water resistivity, mud resistivity/formation water resistivity ratio, bedding thickness, sedimentary structures that influence the permeability, type and degree of cementation, lithologic composition, formation resistivity and hydrocarbon saturation. the factors of this group exhibit insignificant vertical changes in the intervals of massive marls. this is because of the impermeability and lithological homogeneity of marls, the weakly expressed bedding, lack of hydrocarbons and constant formation resistivity. therefore, the factors of the second group do not influence the variation of resistivity at every point, but the variation of an average value instead. a third group is composed of factors that affect the variation of resistivity at every point around the trend-line of the average value. these are: the average grain-size at certain points, the ratio of clay particles, level of sorting and the packing of grains that depends on it, grain-supported or mudsupported structure, type and degree of cementation and compaction level as well as the relationship between cementation and compaction and the shape of sedimentary body. fig. 4 the type resistivity curve with characteristic peaks in the massive marls facies. it is composed by amalgamating the resistivity curves from the o-135 well (rs5 rρ) and the hra-2 well (rρ z’). fig. 3 the identical structure of peaks on the resistivity curve (ra) within the massive marls facies association. the chosen logs are from the wells located in the marginal parts of the sava depression where the facies of massive marls is exclusively developed. interval between the ek-markers rρ and z’ is shown (f fault). 15vrbanac: chronohorizons based on resistivity curve variations... since any change in the physical properties of sediments or any kind of external influence results in a change of the resistivity (respectfully, the electric conductivity), the true formation resistivity can only be measured in undisturbed sediments. in a “clean formation” of the water-saturated sandstone with no clay, the resistivity is a function of the porosity, pore geometry (reflected in the cementation factor) and of the mineralization of the formation water 2: ra = rw / φm (1) where: ra resistivity of formation 100% saturated with water (sw = 1), rw resistivity of formation water, φ porosity, m cementation factor. the porosity depends on grain dimensions, type of packing and on the sorting level. the cementation factor depends on the pore geometry. the more complex the geometry, the higher is the cementation factor. types of packing and pore geometry are also dependent on the compaction level, i.e. on the pressure that is acting on the bed. experience indicates that the resistivity curves in clastic sediments exhibit a general linear increase with depth due to compaction, in other words, that the compaction of sediments causes the resistivity to increase. at the same time, the relationship between fig. 5 ek-marker correlation in the massive marls of the an-1 and o-135 wells. 2 schlumberger ltd., log interpretation, vol. 1 principles, 1974. 16 geologia croatica 55/1 the resistivity of two layers in contact always remains the same. this means that the shape of the resistivity curve still remains the same and curve is only shifted to a range of higher values. a sandstone itself has no electrical conductivity. its resistivity is unmeasurable. the only conduit of electric current is the formation water. the resistivity of formation water is a function of its mineralization. since the mineralization exhibits no significant change even over larger depth intervals, this factor does not affect the shape of the resistivity curve, only its position, or the average value. saturation with oil or gas results in an increase of resistivity proportional to the quantity of hydrocarbons that fill the pore space together with the formation water. resistivity of sandstone layers that contain certain amounts of silt and clay-size particles can be calculated from the following equation2: rt = rsh / vsh + rw / φm (1-vsh) sw n (2) where: rt true resistivity of formation, rsh resistivity of marls (shales), vs h relative proportion of marls (shales) per volume unit, sw water saturation, n saturation exponent. according to the above formula, the proportions of the silt and clay-size particles, as well as their resistivity, significantly influence the bulk resistivity of rock. the clay particles possess a certain level of electric fig. 6 ek-marker correlation in the massive marls of the kri-4 and o-135 wells. 17vrbanac: chronohorizons based on resistivity curve variations... conductivity due to the presence of crystal water. this electrical conduit is independent of the one provided through the water in pores, meaning that the conductivity remains even if the pore water is totally replaced by hydrocarbons. it can thus be concluded that the average granulometric composition, presence of clay minerals and the type of grain packing, the factors that jointly influence the porosity and permeability of rock, are also the factors that significantly influence the amplitude of every peak on the resistivity curve, and in fact the shape of the curve itself. in spite of the fact that these formulae describe the relationships in sandstones without clay particles (1) and the ones with a certain amount of clay (2), they can also be used for the calculation of resistivity in the marl intervals. naturally, the range of average values will then be lower. the marls of this formation largely have the same mineral composition as the sandstones: quartz, feldspar, mica, chlorite and rock fragments (dominated by dolomite and with smaller proportions of limestone, chert and quartzite), but they contain less quartz and more carbonates and clay particles. they are classified as the siltstones and silty marls. within the massive marls intervals there is a regionally recognisable pattern of peaks on the resistivity curve and therefore it is likely that the variations of the above mentioned factors were also regional. this means that there were similar conditions of transport and deposition of clastic material and that the deposition of sediments corresponding to one characteristic fig. 7 ek-marker correlation in the massive marls of the pb-1z and hra-2 wells. 18 geologia croatica 55/1 peak happened concurrently and in the same time interval . therefore, the factors influencing the resistivity variations do not reflect the changes in depositional environment, but rather the minor variations of the relative water level and the related small changes of energy of the transport media that conditioned the composition of clastic material brought into the basin. let us analyse the structure of a set of massive marls, represented on the resistivity curve by a number of characteristic peaks (fig. 9a). since the resistivity variation is an indirect function of the average grainsize and the type of packing, the curve will also reflect the changes of average grain-size. the line drawn through the inflection points of the curve reflects the trend of the average resistivity values. the peaks above and below this line reflect the variation of the maximal (dotted line), and the minimal resistivity values (hatched line). in this way, the exceptionally regular sequence of peaks of higher and lower resistivity values is illustrated; this reflects a sequence of massive marls packages with the same thickness but different resistivity values due to the variable average grain-size, sorting level, type of grain packing and content of clay particles. it can be concluded that the regular sequence of fig. 8 ek-marker correlation in the massive marls of the vl-3 and hra-2 wells. 19vrbanac: chronohorizons based on resistivity curve variations... peaks reflects a sequence of high-order cycles where one of the cycles encompasses one peak of higher and one of lower resistivity values. the sediments of one cycle on the resistivity curve will be regarded as a single cycle (fig. 9b). in this way, the single cycle (sc) is the thin stratigraphic unit composed of hemipelagic sediments that were deposited during one cycle of the relative water level fluctuation in the basin. a cycle is composed of concurrently deposited sediments and the extreme point of resistivity values within every sc have the character of chronohorizons. the relationship between the massive marls and the sandstone bodies presents another problem that has to be explained. according to the spontaneous potential curve of the gl-33 well (fig. 10) the sandstone body “i” is easily observable. the resistivity curve clearly shows that the sandstone body lies within the obvious marked succession of sc-s. a comparison between the sc-s below and above the “i” sandstone in the gl-33 well with those in the o-135 well (taken for reference in this part of the sc-succession), results in a correlation of the sandstone body “i” in the gl-33 well with the sc named “i’” in the o-135 well. it can be observed from the spontaneous potential curve that the sandstone body “i” is not homogeneous, but rather characterised by a variation of the sp that results from a number of thin marl interbeds. illustrated in this example, but based on very numerous cases that can be observed on the logs of almost every well, it can be concluded that a set of massive marls represented by one sc, corresponds to a sequence of depositional events caused by the intermittent activity of the turbidity currents that deposited thinner and thicker layers of sandstone, siltstone and marl in the central parts of the depression. the massive marls represented on the resistivity curve by a succession of sc-s are therefore interpreted as having been formed by deposition of muddy material that was transported into the depression by the permanent and weak, surface, internal and bottom-currents. in the parts of depression characterised by deposition from the intermittent turbidity currents in the same time interval, the sc is correlated with a corresponding “depositional episode”. the episode is composed of a set of sandstone, siltstone and marl layers, each of which was formed by deposition of clastic material transported by a single turbidity current. each of these turbidity currents is an independent event, it transported its own quantity of clastic material and deposited it in a specific area where it has a certain thickness that is laterally variable. there are differences in a number of turbidity currents that form one depositional episode in different parts of the depression, as well as in the surfaces covered by the clastic material of single turbidity currents. under optimal conditions, the maximally obtainable vertical resolution would be to correlate the sediments of one depositional episode. fig. 9 a) cyclic variation of the granulometric composition of massive marls in accordance to the resistivity curve; b) a single cycle. 20 geologia croatica 55/1 4. discussion the single cycle (sc) forms the fundamental genetic unit in the sedimentary sequence, i.e. the one of lowest rank. it consists of massive marl of a particular composition and grain packing, and it encompasses the complete cycle of the variation of granulometric composition. the regularity of the sequence of this genetic unit indicates that every single sc forms only part of a larger stable system that functioned and oscillated throughout deposition of the studied sediments. this oscillation is reflected in the cyclic changes of granulometric composition. although it is within a single lithological member (marl), the cyclicity is seen in the sequence of marl sets characterised by roughly equal thickness, that resulted from the minor and permanent cyclic changes in granulometric composition of the transported muddy material, and in connection with the relative water level variations. according to the rule that relates the thickness of sediments with the time-interval of their deposition (sander, 1936) it is most likely that, under normal stable depositional conditions, the cycles marked by the sediments of equal thickness that are continuously deposited within the studied statistical (time) intervals, also represent equal time-intervals. therefore, it is difficult, if not impossible to imagine depositional mechanisms that lead to such changes in the rate of deposition in different time-intervals which result in the same thickness of sediments. alternatively, the rule states that the same time-intervals are likely be represented by sediments of various thickness, which results from the changes in the rate of deposition. such changes almost always exist, except in the case of a marked stability of the system. it can be observed from the well-logs (figs. 2-8), that the thicknesses of the scs are roughly equal in all the wells. there is insignificant variation between the wells, depending on their location within the depression in other words, variation with the distance from the source area and sedimentation axis, and the position relative to the palaeorefig. 10 correlation of depositional episode a in the gl33 well with the single cycle a’ in the o-135 well, obtained by the precise correlation of the succession of single cycles within the massive marls in both wells. 21vrbanac: chronohorizons based on resistivity curve variations... lief, as well as to compaction (differences in petrostatic pressure and thickness of sedimentary cover). since the deposition of hemipelagic sediments that were the source material for the massive marls occured in the deeper water environment, it can be concluded that the system was stable for a long period of time. it can also be stated with a degree of confidence that the thickness cyclicity reflects higher time cyclicity. this is a case of a specific type of cyclicity which is not based on cycles of repetition of various depositional environments and their corresponding lithological composition, but rather on small, temporally levelled (cyclic) variations of the granulometric composition of clastic material. this material was brought into the depositional basin by the permanent surface, internal and bottom-currents that were active in the generally stable depositional environment over a long time-interval. the occasional “breakthroughs” of turbidity currents, although contributing more material to the depositional area, acted in a limited area and over a very short time-span, and the syngenetic tectonic movements were, according to evidence shown in the massive marls, very slow, and therefore did not influence the stability of the environment and depositional conditions. however, the relative water depth was always deep enough to compensate for water-level variations due to either tectonics, or the influences of climate change. the sedimentary cycle is related to three categories of regularity the regularity in the repetition of either the lithology or the sedimentary structures, the regularity in variation of the thickness of sediments pertaining to one cycle, and the regularity of the time interval that forms the depositional cycle (schwarzacher, 1993). let us analyse the sc-s in respect of these regularities. the first regularity is related to the cyclic changes of granulometric composition and the type of packing. the second is related to the sc thickness variation that results from the oscillation process. in areas where it is exclusively composed of the massive marls facies with characteristic sc-s, the thickness of the ivaniê grad formation is in the order of 150-250 m. comparison of the resistivity curves of a large number of wells resulted in a total number of 82 sc-s as the minimal number of intervals that comprise the complete marl succession of sediments of the studied unit. since the sc-s within a single well are of approximately the same thickness, it can be easily calculated that the average sc thickness is in the range of 1.1 to 3 m. considering the rule that relates the thickness of sediments with the time-interval of deposition (sander, 1936), an approximate calculation of the time-span of a single cycle can be performed. the pannonian interval on the absolute radiometric age scale is between 11.5 and 8.5 ma. supposing that the deposition of the studied sediments, mostly of upper pannonian age, lasted for the one half of this time-span, the calculated duration of the single sc deposition is around 18.3 x 103 years. in other words, deposition occurred in 18.3 x 103 y e a r s cycles. from the approximate determination of the single cycle time-interval, the logical succession of further speculative considerations is in definition of the origin of these cycles. there are two types of oscillating systems that can be applied to solve the question of how the sedimentary cycles were generated. the first type is represented by the self-oscillating systems, among which the so-called tectonic model (bott, 1964) is very interesting and applicable to the studied sediments. a number of factors indicate that this system could have produced the cyclic variation of the relative water level; basin subsidence over a lengthy period, the existence of marginal faults, existence of the shelf and source area that were undoubtedly uplifting, and differences in the temporal pulsation of the prevailing uplift of the source and shelf area with respect to the basin subsidence. since this was environment of moderate water depth, the cyclic changes of the relative water level could not have significantly influenced the depositional conditions. this means that minor cyclic changes in the granulometric composition of the massive marls reflect small variations of the relative depth of water caused by a time-delay between the tectonic movements on the shelf and in the basin area. the large number of the turbidity currents that entered the basin over the duration of single depositional episode results in a number of sandstone interbeds within one episode. this implies that the discontinuous transport of sand-size material from the shelf into the basin area probably was not caused by the aforementioned cyclic variations of the relative water level, but by tectonic activity that led to the continuous uplift of the shelf area. an important aspect of every oscillating system is the question of domain the area of the system’s activity. the registration of recognisable sc-s is taken as the fundamental criterion for definition of the system’s area. therefore, it is without doubt that the area of this system extended throughout the entire sava depression, the whole region between the sava and drava depressions, and over the larger, western part of the drava depression (vrbanac et al., 2000). the size of the domain, together with the long period of time over which the oscillating system was active, indicates the influence of supporting processes at least regional if not global in scale. applying the tectonic model to the sava depression example, the driving and supporting mechanism would be found in the temperature induced extensional subsidence movements (royden, 1988). nevertheless, the acceptability of the tectonic oscillating system has to be assessed very carefully. although the convection currents represent the supporting force of the oscillating system that is very adequate in terms of dimensions and permanency, the most important factor is something else. it is hardly conceivable in this model, that supposed consequent tectonic activities of opposing character, which were active in several separate basins over a large area and of lengthy duration, could have been so ideally composed and equally measured, to have the time-delays between the uplift and subsi22 geologia croatica 55/1 dence tectonic movements necessary for almost ideal cyclic variations of water level of the lowest rank. the second type of oscillating system is the planetary system. its most important characteristic is a greater potential for stability than for any other system that can influence sedimentary processes. this stability is based on well-defined physical laws. the system’s stability is not absolute, there are minor internal variations that can have strong geological effects. it was proved (milankovi∆, 1941) that small cyclic variations of orbital elements (eccentricity, precession, obliquity) influence the amount of solar radiation that reaches the earth’s surface and its atmosphere and in this way indirectly determine the climate. the previously calculed 18.3 x 103 year period of the single sc timeinterval is very close to the cycle amplitude of precession of 18.9 x 103 years calculated by milankovi∆ (1941) and berger (1978). taking in account the exceptionally regular and marked cyclicity of sediments that were surprisingly undisturbed, it is more likely that the variations of water level are directly connected with climate changes, namely with the warmer and colder periods in earth history. there is also the possibility that these cyclic climate variations resulted in cyclic variations of the water temperature and in changes of the energy level at the floor of depositional basin, which caused the variation in granulometric composition. naturally, it has to be noted that there is the possibility that all three factors influenced the aforementioned variations in a certain way. the only measurable value based on which the cyclicity of the studied sediments is supposed, are the thicknesses of the sc-s, and relative to certain cyclic changes in the physical characteristics of sediments. these variations are regretfully not substantiated by adequate analyses, e.g. of the mineral, granulometric and chemical composition. the milankoviê theory was accepted after measurement of isotope signals in deepwater sediments, testing in accordance to the changes of magnetic poles, radiometric age measurement by c1 4 and spectral analysis. none of these measurements were performed in this case. therefore, it can only be supposed that each sc is a reflection of one complete cycle of the rising and lowering of the water level, or energy level fluctuations, or temperature changes of the water. in this way the coarser clastic part of the single cycle represents the low water phase, and the part with finer grains corresponds to the high water phase. although almost insignificant, these fine changes of granulometric composition were inevitably reflected in the type of grain packing. it can be stated that this consideration is a speculative one, for it has observable and clear consequences, but the positive and scientifically acceptable definition of the causes would only be possible after the aforementioned measurements have been taken and analysed. 5. conclusions (1) the dual mechanism of transport and deposition of clastic material in the depression (by turbidity currents and from normal basin currents) is recognised from the resistivity and the spontaneous potential curves. (2) within the massive marls facies, formed by deposition of fine-grained clastic material from the permanent basin currents, single cycles (sc) are distinguishable on the resistivity curve. each sc encompasses one cycle of changes of granulometric composition, and these changes result from the cyclic water-level fluctuation and/or changes in water temperature and energy level on the basin floor. (3) the sc is a basic genetic depositional unit of extremely short time-span (close to the 20,000 years). (4) on the spontaneous potential curve, the sandstone, siltstone and marl layers formed by lithification of clastic material that was brought in by the turbidity currents in the time-interval of one sc deposition (within the cycle of a sc) comprise a depositional episode . (5) the sandstone bodies are composed of sandstone layers of one, two or more depositional episodes. the numbers of sandstone bodies and of depositional episodes forming each body varies along the basin. the distribution and thickness of every sandstone layer was influenced by the mass of transported clastic material, the energy of each turbidity current, the contemporary inclination of slope and by the palaeorelief of the basin bottom. (6) such heterogeneous composition of the sandstone bodies (and respectively of the sandstone reservoirs), explains the very common irregular oilwater contacts in the existing oil fields and the irregular outer contours of the pools. (7) since the majority of the already proven hydrocarbon reserves is contained in the facies of the thicklayered channel sandstones and the lobe sandstones, and to a lesser extent in marginal or distal sandstones, in order to further search for the potential oil and gas fields it is firstly necessary to define the palaeocurrent pattern. (8) the construction of a set of 82 maps of the upper miocene sediments of the ivaniê grad formation, where the area of every single cycle would be separated from the area of depositional episodes with marked facies and palaeocurrent channels, supplemented by the structural and tectonic elements, would provide exceptionally precise input for three-dimensional modelling of regional sandstone reservoirs and of their depositional system within the depression. 23vrbanac: chronohorizons based on resistivity curve variations... acknowledgements an earlier version of this paper was critically read by dr. joæef ©i m o n, ina-naftaplin, zagreb, dr. bruno s a f t i ∆, faculty of mining, geology and petroleum engineering, university of zagreb, prof. h.g. r e a di n g, university of oxford, and dr. györgyi j u h a s z, geological institute of hungary, budapest, who contributed extensive and valuable suggestions. i am also grateful to gordan brzica, gordana raffael-guji∆ and neven butina (ina-naftaplin) on graphic outfit of the paper. 6. references berger, a.l. (1978): long-term variations of daily insolation and quaternary climatic changes.jour. atmos. sci., 35, 2362-2367. bott, m.h.p. (1964): formation of sedimentary basins by ductile flow of isostatic origin in the uper mantle.nature, 201, 1082-1084. milankovi∆, m. (1941): kanon der erdbestrahlung und seine anwendung auf das eiszeitproblem.akad. r.s., 133, 1-633. najdenovski, j., hernitz, z. & bla©kovi∆, i. (1983): a review on the geological relations of variscides in the southeastern part of the pannonian basin.newsletler igcp (unesco), 5/5, 108-117, padova. pandæi∆, j. (1980): pretercijar jugozapadnog dijela panonskog bazena (geology of the pre-tertiary base of southwestern part of the pannonian basin).unpublished phd thesis, university of beograd, 183 p. pletikapi∆, æ. (1965): stratigrafija, paleogeografija i naftoplinonosnost ivaniê grad formacije na obodu moslavaëkog masiva (stratigraphy, paleogeography and oil gas possibilities of the ivaniê grad formation on the border of the moslavaëka gora range).unpublished phd thesis, university of zagreb, 71 p. royden, l.h. (1988): late cenozoic tectonics of the pannonian basin system.aapg mem., 45, 27-48. sander, b. (1936): beiträge zur kenntnis der anlagerungsgefüge (rhytmische kalk und dolomit aus der trias).mineral. petrogr. mitt., 48, 27-209. schwarzacher, w. (1993): cyclostratigraphy and milankovitch theory.elsevier, amsterdam, 225 p. ©imon, j. (1970): prilog stratigrafskoj analizi tercijarnih sedimenata na sjeverozapadnom predjelu savske potoline.vii kongr. geol. jugosl., 1, 347-360, zagreb. ©imon, j. (1973): o nekim rezultatima regionalne korelacije litostratigrafskih jedinica u jugozapadnom podruëju panonskog bazena (some results of regional correlation of lithostratigraphic units in the southwestern part of the pannonian basin).nafta, 24/12, 623-630, zagreb. ©imon, j. (1980): prilog stratigrafiji i taloænom sustavu pjeπëanih rezervoara sava-grupe naslaga mlaeg tercijara u panonskom bazenu sjeverne hrvatske (contribution to stratigraphy and depositional system of sandstone reservoirs of sava group younger tertiary deposits in pannonian basin, northern croatia).unpublished phd thesis, university of zagreb, 66 p. vrbanac, b. (1996): paleostrukturna i sedimentoloπka analiza gornjopanonskih naslaga formacije ivaniê grad u savskoj potonini (paleostructural and sedimentological analysis of the upper pannonian deposits of ivaniê grad formation in sava depression).unpublished phd thesis, university of zagreb, 125 p. vrbanac, b., ©imon, j. & hernitz, z. (2000): sjeverna hrvatska tijekom gornjeg panona plitkovodni ili dubljovodni taloæni bazen?in:vlahovi∆, i. & biondi∆, r. (eds.): 2nd croatian geological congress, cavtat dubrovnik, proceedings, 469-474, zagreb. manuscript received september 1, 2000. revised manuscript accepted may 20, 2002. 24 geologia croatica 55/1 1. introduction regional geochemical mapping makes use of various sample media which offer the general prospect either of finding a particular type of mineral deposit or, more commonly, of locating the presence of certain anthropogenic contaminants. opinions on the particular advantages and drawbacks concerning different types of sample materials have been amply described (e.g. reimann, 1988; ottesen et al., 1989; macklin et al., 1994; edén & björklund, 1994; pulkkinen & risanen, 1997; huisman et al., 1997; swennen & sluys, 1998; swennen et al., 1998, and others). yet, owing to the fact that all of these are not readily available in different parts of the globe, the general consensus has not been established hitherto, which is why the regional and local schemes of geochemical survey in various countries, and sometimes even in the same country, differ accordingly. in croatia, regional geochemical mapping is based upon soil as the primary sample medium. this is mainly due to the fact that soil is the only sample material geochemical comparison of stream and overbank sediments: a case study from the æumberak region, croatia zoran peh and slobodan miko available throughout the country, particularly when the southern, almost entirely carbonate terrains are considered. in the northern, pannonian region, owing to the expansive drainage system, other sample materials, e.g. stream or overbank sediments, can be found in abundance. as a consequence, the question may arise whether stream sediment, or soil, or, perhaps some other type of regolith material, would be the most appropriate for sampling in order to detect the greatest variation among geochemical data. this is particularly of interest in areas where two distinctly different lithologies, such as carbonate and non-carbonate sedimentary rocks, associate in a complex way (as in the æumberak region). it should be emphasized that soil sampling, when compared to the sampling of stream or overbank sediments, is based on an altogether different philosophy. the first approach is, as it were punctuated, with no strictly defined conjoined area of underlying bedrock influence, regardless of the chosen sample design. the second approach is area-related which increases the possibility of reflecting the surface lithology of the whole area upstream from the sampling site. besides, when observing the drainage basin as a fundamental geomorphological unit (chorley, 1969), it is certain that less bias would be inferred if one can deem it to be an area originated and embedded in the surrounding landscape by a set of natural processes pertaining not only to the strictly geomorphological but also to the geochemical domain. this is why many authors, especially from the northern, carbonate-free part of europe, but also elsewhere in the world, applied, as a rule, the catchment basin analysis in their geochemical research (bonham-carter et al., 1987; carranza & halle, 1997; ódor et al., 1997, and others). thus, the sampling of appropriate media in a catchment basin is rendered desirable wherever the landscape allows it, because their geochemical assemblage may elucidate the average composition of this unit area more faithfully than any of the soil sampling designs. this may be of particular value in the case of geochemical reconnaissance both in the regions suspected of mineralization or for possible pollution. when reconnaissance geochemical surveys are carried out in lowto medium-order drainage basins, where both stream and overbank sediments are obtainable for sampling, it may not be obvious as to which of geologia croatica 54/1 119 130 6 figs. 4 tabs. zagreb 2001 key words: geochemical mapping, drainage basin approach, stream sediment, overbank sediment, discriminant analysis, æumberak, croatia. institute of geology, sachsova 2, hr-10000 zagreb, croatia. abstract geochemical comparison between the stream and overbank sediments from lowto medium-order drainage basins is grounded on the presupposed statistical contradistinction of their locality-paired sample correlatives. discriminant analysis differentiated the overbank from stream material mainly on account of higher content of most of the analyzed elements in the former vis-à-vis an otherwise common geochemical semblance. only the carbonate material seems to be depleted in overbank sediment samples. investigations also demonstrated that in the relatively non-contaminated area it may be more difficult to verify the supposed purity-contamination reciprocity between the investigated media, since the recent and prehistoric materials were not contrasted as regards their non-lithogenic components. 120 geologia croatica 54/1 these media, or perhaps both, should be sampled in order to acquire the best geochemical information from the study area. granted that processes having control over the mass movement within the catchment basin are common in both cases, one may suppose a subsequent similitude in their overall geochemical assemblage, with only a small variation in the data. nevertheless, for practical consideration a time dimension should always be taken into account, especially in validating the anthropogenic versus natural contribution to the chemical content of alluvial materials. this is due to the fact that stream sediment represents an active material of recent origin which is temporarily suspended on a stream bed, while overbank sediment indicates alluvial regolith of earlier depositional cycle(s) produced as a result of extensive floods (ottesen et al., 1989). on this premise, a tacit assumption is made about the main difference in the geochemical composition between the two types of alluvial sediment. namely, overbank sediment (except in its uppermost section) should represent an unpolluted, pristine medium when deposited in a natural, pre-industrial environment, while, on the other hand, stream sediment is expected to reflect every kind of recent contamination that may arise in the investigated area. furthermore, geochemical variation resulting from potential mineralization within a catchment basin is supposedly detectable in both. therefore, the immediate scope of the present study will be to explore the geochemical difference between these two sample media in an area with a well-known overall geological setting and expected, but minor, anthropogenic influence. it will hopefully shed some light on the possible advantages in utilization of one or, perhaps, both of these sample media in further lowto medium-density geochemical mapping of some target areas in croatia. 2. description of the study area æumberak is a mountainous territory located to the west and in the immediate vicinity of the croatian capital of zagreb. to the north and west it is bordered by slovenia, and to the south by the kupa river, while its east and southwest portions gently dip towards the karlovac depression (fig. 1). the landscape combines the features of dinaric, highly dissected, carbonate terrains abounding in various karstic phenomena such as sinkholes, together with pannonian, mostly non-carbonate terrains of moderate relief and with a regular drainage network. the highest point in the area is the summit of sveta gera (1,160 m), while the surrounding valleys of the sava, krka and kupa rivers with their terraces do not exceed altitudes of about 200 m. 2.1. geological setting the study area is geologically mapped at 1:100,000 scale and presented mostly on the sheet of zagreb (©iki∆ et al., 1978). only a small portion falls within the sheets of »rnomelj (bukovac et al., 1983) and novo mesto (pleni»ar et al., 1976). geotectonically, it belongs to the broad boundary zone between the dinaric carbonate platform (dinaricum) spreading to the southwest, and adjacent inner dinaride area (supradinaricum) lying on the northeast (herak & bukovac, 1988; herak, 1991). the geotectonic character fig. 1 simplified geological map showing location of the study area (after bukovac et al., 1983; ©iki∆ et al., 1978; pleni»ar et al., 1976). legend: q2) holocene in general; q1) pleistocene in general; plq) plio-quaternary: unconsolidated sediments; ng) neogene in general: clastic rocks; k2) upper cretaceous: limestones, dolomites and flysch; j) jurassic in general: predominantly limestones; t3) upper triassic: predominantly dolomites; t1) lower triassic: predominantly clastic rocks; p2 , 3) middle and upper permian: predominantly clastic rocks. is well reflected in the intricate tectonic and, particularly, lithological patterns. the oldest rocks in the area are mostly clastic sedimentary rocks of middle and upper permian age. these consist predominantly of sandstones, more rarely of conglomerates, shales and siltites. apart from the clastic rocks, limestones and dolomites occur sporadically. the early triassic rocks are prevalently non-carbonate, mostly sandstones in their lower part with increasing portions of carbonate component toward the upper levels. sedimentation was continuous until the middle and upper triassic in predominantly carbonate facies. the upper triassic dolomites are the most significant lithological member of the series. jurassic sedimentary rocks are almost entirely carbonate with limestones as a dominant member, while the overlying discordant upper cretaceous rocks consist of a thick flysch-type series which was deposited during the cenomaniansenonian period. the latter include predominantly calcareous and clayey marls and calcarenites which, together with the former, frame the margin of the dinaric carbonate platform. their contact with the surrounding upper triassic dolomites (supradinaricum) is clearly tectonic, the nappe front frequently masked by vertical neotectonic faults (herak & bukovac, 1988). frequent tectonic activity with periodic changes of depositional environment during the tertiary resulted in greater diversity of the clastic sedimentary facies. from palaeocene to pliocene, a variety of clastic sedimentary rocks were formed, mostly sandstones and marls. carbonate clastic rocks predominate only through the badenian. the transition into the quaternary was marked by the onset of freshwater sedimentation with an extensive and thick series of lithofacially differentiated sediments from gravel to clays. plioquaternary sediments occupy a considerable part of the study area, particularly its lowered southern rim border ing the karlovac depression. quaternary deposits are represented almost entirely by the holocene alluvial sediments of the local streams. 2.2. mineral occurrences mineralization in the investigated area is related mostly to the layers or veins hosted in the fine-grained clastic permian rocks. apart from a number of scattered fe, pb, zn, cu, au and hg occurrences together with gypsum and barite, there is a small-scale siderite-haematite-sulphide ore deposit in the valley of rudarska gradna. until the middle of the last century it had been mined extensively for iron for a few hundred years. the iron ore typically occurs in the form of a siderite layer of submarine sedimentary origin interstratified between the palaeozoic sandstone beds (©inkovec, 1971; ©iftar, 1989). the main ore body is accompanied by haematite lenses as well as with sulphide veins containing chalcopyrite and a barite-galena paragenesis. the latter occur invariably in the underlying sandstone strata, while the overlying sandstone series contains in its uppermost parts the thick (45 m) gypsum-anhydrite bed (©inkovec, 1971) which marks the border with the triassic. small mineral occurrences of the same origin are widely disseminated through the permian outcrops of the nearby valleys such as lipovaëka gradna and ludviê, as well as okiênica. a different type of mineralization can be found in the western part of the investigated area. it appears as small remnants of sedimentary limonite deposits covering the middle and upper triassic dolomite palaeosurface. a few such occurrences are strewn over the area of the slapnica valley, north of kraπiê. 2.3. anthropogenic influence the area of investigation is free from the immediate impact of great industrial or other sources of contamination. the nearest industrial center, the capital city of zagreb, is more than 20 kilometres away to the east. small cities such as samobor, scattered on the perimeter of the investigated mountainous area, do not employ industries of great scale or pollution capacity. there are, however, two known sources of human influence that may be observed in the local catchment areas. one can be ascribed to the bygone mining activities that may have left traces of increased concentrations of heavy metals such as pb, zn and fe both in the stream and overbank sediments within some of the loworder catchments. the other can result from recent agricultural activity, generally viniculture, with anticipated increases in cu (from bluestone) and p (from fertilizers). the former is restricted to the inner, mountainous part of the study area, while the latter can be found scattered over the wider zone of the southern slopes of samoborsko gorje, particularly in the surroundings of kraπiê and jastrebarsko. 3. materials 3.1. sampling more than forty lowto medium-order drainage basins ranging in size from 0.65 to 122.94 km2 were sampled, in a close-spaced sampling design covering the territory of approximately 600 km2 (fig. 2). for a closer inspection into the sources of geochemical variance between the stream and overbank sediments the paired samples of both media were regularly collected from the same sample site (within a few metres). this procedure necessarily excluded a number of smaller, dominantly mountainous drainage basins (mostly of the fourth order) from the analysis, where only stream samples were available for sampling. a total of 40 sites with both stream and overbank material have been sampled over the entire area (table 1), a sampling density of approximately one sample per 15 square kilometers being thus defined. 121peh & miko: geochemical comparison of stream and overbank sediments... 122 geologia croatica 54/1 the sample sites were selected at the basin outlets, sufficiently upstream from the confluence with higher or same order streams in order to avoid sampling the sediment that may result from mixing of material from the two channels during the flood flow. an active stream sediment, which represents the composite of the recently deposited bed load material, was collected from several spots (ordinarily 5-10 as recommended by salminen et al., 1998) over a short channel stretch upstream of the selected site. simultaneously, a single overbank sediment sample was taken from approximately the same point at the exposed area of either bank of a channel. the latter is composite material taken from the bank section ranging in height from 25 cm beneath the surface down to the water level (usually 0.5 to 2 m thick), while the first 25 cm of upper, near surface, horizon was avoided because of possible anthropogenic disturbance and pedogenesis. in both cases a quantity of about 3 kg of sediment was collected to yield enough representative material for sieving and analysis. 3.2. sample preparation collected samples were air-dried (at <40°c) for approximately three months. after drying, the samples were disaggregated in a porcelain mortar, homogenized, and finally dry-sieved through stainless-steel screens to the fraction of <125 µm. this fraction was preferred because the highest concentration of most of elements, especially trace elements, occur in the finegrained, usually from 63 to 125 µm size fraction (e.g. rhoads & cahill, 1998). also, different studies show that the <125 µm size fraction makes up more the 95% of the particles in most samples (swennen et al., 1998). 3.3. analytical methods analytical work was performed at the acme analytical laboratories in vancouver, canada, where samples were subjected to multi-acid digestion icp analysis, and geochemical hg analysis by flameless aa. a total of 36 elements were thus analyzed with au, be, bi, mo, u and w invariably, and ag, sb, sn and cd mostly having concentrations below the detection limit. elements such as th, y, nb and sc were measured slightly above the threshold, so that all of these were omitted at the outset from further considerations. 4. statistical analysis 4.1. univariate statistics and data transformation a set of 22 elements was used in statistical analysis. eight major and 14 minor and trace elements were selected as predictor variables in the process of discrimination. table 2 displays the summary statistics of the analytical data including the skewness coefficient as a measure of normality. due to the fact that a number of variables in both groups show highly positively skewed fig. 2 sample map. 123peh & miko: geochemical comparison of stream and overbank sediments... frequency distributions, transformation must have been carried out for most of the minor and trace elements such as hg, pb, cu, sr, ba, as, zn and cr, but also for some major elements such as ti and p. the process of conventional logand ln-transformation was applied separately for each group, but in some cases (ni for example) the results were poorer than original distributions. in such instances the variables were left natural (the total data set can be requested from the authors). 4.2. basic principles of discriminant analysis geochemical variation between the two investigated sample media, already “known” to be geochemically separable, can be thoroughly investigated by the use of multivariate discriminant analysis. thus, the two-group (k=2) problem is introduced which presents the simplest case with a solitary discriminant function as a basis for separation. in analysis these groups are labelled stream or overbank, respectively. the discrimination procedure revolves generally around how to compute a linear combination of original (predictor) variables that will best distinguish between the groups. this is achieved by both maximizing the ratio of between-group in comparison to within-group variability and generating the smallest misclassification errors (dillon & goldstein, 1984; davis, 1986; rock, 1988). the latter is also enhanced by limiting case sample drainage basin order catchment area (km 2) 1 41 ludviê 4 sava 4.41 2 194 orejovec 4 kupa 5.25 3 196 piroπki potok (slo) 4 krka 6.03 4 197 skradnja (slo) 4 krka 5.07 5 214 fuëanski jarak 4 sava 2.81 6 221 velika draga 4 sava 2.99 7 349 jaπevnica 4 kupa 12.02 8 351 ponornica 351 4 krka? 1.01 9 354 ponornica 354 4 kupa? 2.86 10 366 vorbaπëica 4 kupa 4.56 11 371 potok 371 4 kupa 0.65 12 19 ©krobotnik 5 sava 8.79 13 21 breganica 5 sava 11.21 14 42 lipovaëka g. 5 sava 26.00 15 43 rudarska g. 5 sava 15.48 16 178 reka 5 kupa 9.19 17 187 okiênica 5 kupa 19.11 18 190 potok 190 5 kupa 3.15 19 198 suπica (slo) 5 krka 9.79 20 275 bregana 5 sava 14.52 21 276 rakovac 5 sava 8.39 22 328 æumberaëka reka 5 kupa 15.96 23 331 suπica 5 krka 8.51 24 333 suvaja 5 kupa 22.91 25 334 potok 5 kupa 5.44 26 335 svilnica 5 kupa 3.63 27 337 ponikva 5 kupa 6.46 28 338 slapnica 5 kupa 16.25 29 339 puπkarov jarak 5 kupa 9.77 30 340 brebrovac 5 kupa 5.69 31 342 stiska 5 kupa 11.43 32 343 malunja 5 kupa 6.87 33 344 gonjeva 5 kupa 8.11 34 345 kamenica 5 kupa 17.23 35 346 bukovica 5 kupa 12.25 36 347 slatinek 5 kupa 4.33 37 368 stiper 5 kupa 5.72 38 370 selna 5 kupa 5.32 39 18 bregana 6 sava 57.40 40 72 kupëina 6 kupa 122.94 table 1 general data describing the sample sites. 124 geologia croatica 54/1 the size of both groups at an approximately equal number of objects so that the optimal cutting score is placed exactly between their centroids. graphically, the calculated discriminant function portrays a new axis along which the groups are maximally set apart. finally, according to variables with the most prominent discriminant loadings, geological meaning could be attached to the axis. thus it can be labelled with regard to a specific gechemical process which is liable for separation between the groups. other measures for determining the individual contribution of predictor variables, such as the standardized coefficients, may be often fairly misleading as they are more subject to instability caused by intercorrelations between discriminatory variables (dillon & goldstein, 1984). 5. results the results of the two-group discriminant analysis are briefly summarized in table 3. owing to data standardization the optimal cutting score for the two groups of equal abundance (40) has a zero value, with the group centroids placed at equal distance from the cutting point along either side of the discriminant axis. on the value of the test statistics the difference in the separation of the stream and overbank centroids can be judged as statistically significant, although a few samples in both groups appear to be more loosely scattered about their means. accuracy of the discrimination procedure can be inspected from the classification matrix (table 4). 69 samples out of total of 80 in the data set are correctly classified on the basis of their geochemical composition, which makes 86 percent for the combined population of both groups. as can be seen from the table 4, the unequal classification efficiency of the two groups shows that these are asymmetrically discriminated. better results are achieved with the stream group having only three misclassified samples (7.5 percent incorrect), while overbank shows much more asymmetry with 20 percent of inaccurately classified samples. this asymmetry, however, does not diminish the efficacy of discrimination between the two sample media, particularly considering the problems of multivariate normality (rock, 1988). despite the recommended normalization procedures of observed data, some variables still tend to be distributed differently in both groups, which results in unequal dispersion of predicted groups. when the significance of a particular subset of elements in the general discrimination scheme is considered, it is evident that in spite of the apparently bipolar nature of the discriminant function, the accent is heavily placed on the positive pole (fig. 4), where the bulk of the analyzed elements are loaded. the axis weighs v, al, fe, zr and la against essentially a single element ca, which is obviously a reflection of the inverse relationship between the aluminosilicate and carbonate component in the two sample media. owing to their low discriminant loadings, other elements add little to stream overbank mean st.d. skew. mean st.d. skew. fe (%) 1.55 0.67 0.17 2.25 0.86 0.83 ca (%) 9.56 4.90 -0.20 7.10 4.16 0.11 mg (%) 3.28 2.50 0.45 2.67 2.12 0.89 ti (%) 0.22 0.13 2.48 0.25 0.07 -0.17 al (%) 2.94 1.20 0.00 4.18 1.22 0.19 na (%) 0.36 0.15 0.72 0.41 0.11 0.51 k (%) 0.80 0.35 0.33 1.08 0.41 1.40 p (%) 0.05 0.02 1.76 0.04 0.01 0.89 cu (ppm) 21.63 18.10 3.89 41.55 101.33 6.19 pb (ppm) 42.43 149.09 6.29 25.7 20.11 3.41 zn (ppm) 47.23 21.17 1.70 56.28 24.92 2.94 ni (ppm) 27.93 17.08 1.20 40.23 19.78 1.25 co (ppm) 9.25 5.14 0.60 13.00 5.81 0.30 mn (ppm) 757.13 509.10 0.73 847.65 590.75 1.12 as (ppm) 8.08 3.75 1.77 9.76 7.24 2.95 sr (ppm) 118.83 100.56 2.68 128.20 127.61 3.06 v (ppm) 49.25 18.37 0.32 70.10 19.26 0.15 la (ppm) 19.15 8.51 0.05 25.60 7.78 -0.38 cr (ppm) 47.68 24.66 1.53 58.80 19.70 0.46 ba (ppm) 195.03 118.46 2.63 337.93 589.20 6.09 zr (ppm) 24.6 11.73 0.26 33.68 11.63 0.10 hg (ppb) 62.63 139.00 6.10 363.48 1831.75 6.31 table 2 univariate statistics (mean, standard deviation and skewness) of major, minor and trace elements in the stream and overbank sediment samples of the æumberak region. 125peh & miko: geochemical comparison of stream and overbank sediments... the geochemical distinction between stream and overbank. this is particularly evident with some major and minor elements such as mg, na, ti, p, but also mn and sr. 6. discussion comparison between the classification results represented by the plot of all samples (fig. 3) against the plot of variable contributions (fig. 4) along the discriminant axis offers insight into the geochemical relationship between the groups. there is an immediate impact of stream and overbank sediments differing primarily in the relative abundance of a bulk of analyzed elements, as only ca (and disregarding mg and p) can be found increased in the stream samples. this can be interpreted in two ways: either as an indication of the predominantly carbonate character of the active stream sediment in the investigated catchment basins, or (not excluding the first), that material composing the overbank samples contains greater concentrations of elements with a higher natural variability and considerably higher metal contents (particularly v, al and fe). the latter can be of interest in further investigations for possible anomalies concerning mineralization or contamination in the study area. the main reason for the shift to the increase of ca in the stream sediments can be sought from two sources. one is probably due to the dominant carbonate lithology in most of the sampled drainage basins over two-thirds of their area is underlain by dolomite and limestone. however, having in mind that we are dealing here with the present-day stream bed material, it cannot, naturally, represent the whole catchment area but is limited only to a portion which is exposed to recent fluvial erosion (ottesen et al., 1989). most obviously, the central part of the æumberak, undergoing vigorous tectonic uplift (prelogovi∆, 1969), provides an ample source of carbonate material which is eroded from the bedrock in the deeply cut valleys (such as bregana, for example) and feeds the sample sites at the basin outlets. regional tectonic influence is of particular importance because it represents a clear-cut example that a tacit assumption of equal erosion through the whole drainage basin may not be true (rose et al., 1979). the lower parts of the sampled drainage basins, especially in the southeast part of the studied area (the catchment of the kupa river) are distinguished by the processes of aggradation or, at least, by the greatly reduced capacity for erosion due to the low channel gradients. of no lesser significance is that their stream channels, particularly those of higher order (fifth and sixth), run mostly through non-carbonate (neogene clastic) rocks, highlighting the contrast between “alien”, more carbonate, recent material in the stream bed and adjacent overbank. the other reason for the higher content of ca in the stream samples as contrasted with its overbank counterpart is of a geochemical nature and still more emphasizes their recentness. during the short depositional history of the stream sediment, the friable ca and mg minerals from dolomite and limestone were subjected mostly to physical weathering which resulted primarily in the finer grain size of clastic particles downstream. chemical weathering contributes little to the loss of carbonate material via running water and out of the system (which also includes the riverplain), especially in the æumberak streams which are weakly alkaline (ph = 7-8). on the other hand, most of the dissolved material number of variables in model (p) 22 number of groups (k) 2 number of functions (k-1) 1 number of cases (n1, n2) 40, 40 approximate f ratio (degrees of freedom) 4.04 (22, 57) p-level 0.000008 canonical r 0.78 average r value for stream (centroid), r1 -1.23 average r value for overbank (centroid), r2 1.23 mahalanobis distance d2 6.23 table 3 compositional differences between stream and overbank sediments. predicted group observed stream overbank % total group (p=0.5) (p=0.5) correct stream 37 3 92.50 40 overbank 8 32 80.00 40 total 45 35 86.25 80 table 4 classification matrix. 126 geologia croatica 54/1 in the streams comes from solution by groundwater (easterbrook, 1969). this is the process, perhaps, that accounts for most of the lack of ca and mg in overbank sediment over the study area, namely, decalcification of the previously deposited alluvium due to fluctuating hydrological conditions in the area. the dissolution of carbonate minerals in the overbank sediment is induced by the raising of the groundwater level which creates periodic waterlogged conditions with a significant decrease in ph in the upper part of the overbank profile (berg & loch, 1998). in the two-group discrimination model it is reflected the other way round, that is, through the increasing carbonate component in the stream group. the second indication distinguishing the two sample media, as seen in fig. 4, is related to the greater deficiency of analyzed elements in the stream sediment. lower overall concentrations in this material have been generally observed earlier (e.g. reimann, 1987; swennen et al., 1998), and can be accounted for the fact that much of the element contents (v, al and fe in particular in this case) are dispersed in the finer fraction (silt-clay) which is winnowed out leaving the stream sediment coarser and “depleted”. apart from being accordingly attenuated, this material is also fairly nonhomogeneous as can be seen from the asymetrically shaped histogram of discriminant scores (ds) for stream (fig. 5a). in contradistinction to its stream counterpart, the overbank sediment appears to have a higher “natural” background, much on account of its longer depositional history which supplied it with a mixture of geochemical fig. 3 plot of discriminant scores (ds) (projection of samples onto discriminant function line). fig. 4 plot of discriminant loadings (projection of variables onto discriminant function line). 127peh & miko: geochemical comparison of stream and overbank sediments... and mineralogical characteristics that embrace the whole drainage area upstream from the sample site. this is particularly important with respect to the distribution of heavy metals and trace elements in both sample media (originating either from ore mineralization or man-made pollution) because, as can be seen from fig. 4, there is no preferential distribution pattern. apart from the relative abundance of non-carbonate components in the overbank sediment, a much greater geochemical homogeneity of precipitated material (analyzed as a composite sample) can also be expected. this is clearly shown by the normally distributed discriminant scores for overbank (fig. 5b). the more uniform dispersion of chemical elements through overbank samples affects the boundary between overbank and stream groups making it a little unilaterally diffuse. as a result, more overbank samples with lower element concentrations are lost to the other group showing more affinity with the stream sediment. the cohesion of the stream group can be deemed considerable as only three samples bear more similarity with adjoiningly sampled overbank. this is obvious from closer inspection into the areal distribution of discriminant scores for both groups (figs. 6a and b). excluding the eastern borders of the studied area, where the overbank composition clearly conforms with entirely noncarbonate bedrock, it may be hard to locate an uninterrupted section with a greater agglomeration of drainage basins containing highly discriminated overbank samples (ds>1), despite attempting to relate them with the underlying bedrock. conversely, the stream sediment characteristics are much more perceptible on the terrain as the pertinent basins are scattered almost evenly all over the study area (ds<-1) with only a minor clustering along its southern and northern fringes: stream sedi ment samples in the southwest are almost indistiguishfig. 5 a) histogram of discriminant scores for stream; b) histogram of discriminant scores for overbank. a b 128 geologia croatica 54/1 b a fig. 6 a) map displaying the areal dispersion of discriminant scores for stream. legend: 1) misclassified samples (ds>0); 2) weakly separated samples (-1<ds<0); 3) well separated samples (-2<ds<-1); 4) extremely separated samples (ds<-2). b) map displaying the areal dispersion of discriminant scores for overbank. legend: 1) misclassified samples (ds<0); 2) weakly separated samples (0<ds<1); 3) well separated samples (1<ds<2); 4) extremely separated samples (ds>2). 129peh & miko: geochemical comparison of stream and overbank sediments... able from the adjacent overbank (-1<ds<0) which obviously concurs with the underlying senonian flysch, mostly marls, producing a weak geochemical contrast between the two sample media. the basins in the central south are best discriminated probably due to the share of contrasted lithologies their upper parts draining the carbonate, almost entirely dolomitic bedrock, while the lower portions overly the neogene, essentially non-carbonate terrain, which enhances the contrast; the basins in the south-east and the north conform with the foregoing picture with one noticeable distinction. there is but one stream sediment sample that not only deviates markedly from its own group (more than two standard deviations) but is, moreover, placed among the most prominent members of the other group. such a misclassification (sample 344-gonjeva, fig. 3), provided that the sampling procedure was correctly carried out, is ultimately due the causes other than regular erosion-aggradation processes in the vicinity of the sample site (the fifth-order drainage basin of gonjeva, which is the tribute of the kupa river). it is assumed that the nature of drainage basin processes that brought about the discussed differences between stream and overbank groups cannot differ greatly over small area of the few tens of kilometres across. actually, such a case is probably induced by poor geomechanical properties of the bank material, having an impact on the slope stability at the sampling site or upstream. the bank failure might have been triggered by hydrogeological causes, probably by rainfall, somewhere along a two-metre high levee, the slump being resedimented downstream as fine-grained bedload. another cause is possibly lateral erosion and reworking of the overbank material due to the slight meandering of the gonjeva channel at the sampling location. the process of stream downcutting through its own alluvium in view of tectonics may be ruled out on account of the absence of similar anomalies in the nearby drainage basins (190, 194). besides, the lower part of the gonjeva stream runs through the karlovac depression which is currently undergoing a stage of steady tectonic subsidence (veli∆, 1983). 7. conclusion geochemical comparison of the lowto medium-order stream and overbank sediments based on the direct contrast between locality-paired samples was conducted to elucidate the possible differences in natural geochemical variation in both media. of particular interest was spotting the disposition of a subset of elements for a specific medium explainable in terms of either mineral ore occurrences or anthropogenic influences (mostly municipal) in the investigated drainage basins. this would help narrow the focus of interest onto the medium with better availability to sampling, as well as lesser problems of interpretation. the media comparison was performed using twogroup discriminant analysis which allowed the best insight into the group structuring and differences caused by the selective contribution of predictor variables. the results can be summarized as follows: a) stream and overbank are well separated groups with 86.25% correctly classified samples (only 11 out of 80 are misclassified). b) the total element content is much more uniformly dispersed in the overbank material, obviously as a result of recurrent flooding and mixing during its depositional history. c) the geochemical difference between the sample media is conveyed almost entirely by the higher content of the greatest part of analyzed elements in the overbank sediment. d) overbank sediment is depleted in carbonate material (ca, mg), perhaps due to decalcification. e) vanadium is the trace element with the highest discrimination potential, increased in overbank sediment. f) there is no apparent preference of heavy metals and trace elements with regards to either sample medium evidence of mineralization and pollution is screened by the reciprocal “abundance-scarcity” relationship between the media. concerning the fact that the investigated catchment basins are of an order that almost invariably supplies both media with sample material, one can draw a fairly resolute choice between these, at least on regional level, on account of the clues inferred above. in comparison to its stream correlate the overbank sediment seems to be more convenient for sampling, especially by reason of its higher natural geochemical variability on the background of an otherwise common geochemical semblance. in a relatively low-polluted area, such as the investigated æumberak region, an active stream sediment, which is a sample medium of recent origin, is not capable of indicating the presence of pollutants in contrast to its presumably pristine, pre-industrial overbank associate. more so since the mineral ore occurrences can be detected regularly in both recent and earlier sedimented material. 8. references berg van den, g.a. & loch, j.p.g. (1998): decalcification of soils in wetlands subject to fluctuating hydrological conditions.in: berg van den, g.a. (ed): geochemical behaviour of heavy metals in a sedimentation area of the rivers rhine and meuse. geologia utraiectina, 163, 21-39, utrecht. bonham-carter, g.f., roger, p.j & ellwood, d.j. (1987): catchment basin analysis applied to surficial geochemical data, cobequid highlands, nova scotia.j. geochem. explor., 29, 259-278. 130 geologia croatica 54/1 bukovac, j., ©u©njar, m., poljak, m. & »akalo, m. (1983): osnovna geoloπka karta sfrj, 1:100.000, list »rnomelj, l33-91 (basic geological map of sfrj, 1:100.000, the »rnomelj sheet).geoloπki zavod zagreb and geoloπki zavod ljubljana (1972-1983), savezni geoloπki zavod, beograd. carranza, e.j.m. & hale, m. (1997): a catchment basin approach to the analysis of reconnaissance geochemical-geological data from albay province, philippines.j. geochem. explor., 60, 157-171. chorley, r.j. (1969): the drainage basin as the fundamental geomorphic unit.in: chorley, r.j. (ed.): water, earth and man. methuen and co., london, 72-99. davis, j.c. (1986): statistics and data analysis in geology.2nd ed., john wiley & sons, new york, 646 p. dillon, w.r. & goldstein, m. (1984): multivariate analysis: methods and applications.john wiley & sons, new york, 575 p. easterbrook, d.j. (1969): principles of geomorphology.mcgraw-hill, new york, 462 p. edén, p. & björklund, a. (1994): ultra-low density sampling of overbank sediment in fenoscandia.j. geochem. explor., 51, 265-289. hawkes, h.e. (1976): the downstream dillution of stream sediment anomalies.j. geochem. explor., 6, 345-358. herak, m (1991): dinaridi: mobilistiëki osvrt na genezu i strukturu (dinarides: mobilistic view of the genesis and structure).acta geologica, 21/2 (prir. istraæ., 63), 35-117 (1-83), zagreb. herak & bukovac, i. (1988): the tectonic window of duralije in æumberak mt.geol. vjesnik, 41, 231-236. huisman, d.j., vermuelen, f.j.h., baker, j., veldkamp, a., kroonenberg, s.b. & klaver, g.th. (1997): a geological interpretation of heavy metal concentrations in soils and sediments in the southern netherlands.j. geochem. explor., 59, 163-174. macklin, m.g., ridgway, j., passmore, d.g. & rumsby, b.t. (1994): the use of overbank sediment for geochemical mapping and contamination assessment: results from selected english and welsh floodplains.appl. geochem., 9, 689-700. ódor, l., horváth, i. & fügedi, u. (1997): low-density geochemical mapping in hungary.j. geochem. explor., 60, 55-66. ottesen, r.t., bogen, j., bølviken, b. & volden, t. (1989): overbank sediment: a representative sample medium for regional geochemical mapping.j. geochem. explor., 32, 257-277. pleni»ar, m., premru, u. & herak, m. (1976): osnovna geoloπka karta sfrj, 1:100.000, list novo mesto, l33-79 (basic geological map of sfrj, 100.000, the novo mesto sheet).geoloπki zavod ljubljana (1963-1969), savezni geoloπki zavod, beograd. pulkkinen, e. & risanen, k. (1997): a geochemical investigation on overbank sediments in the inari area, northern finnish lapland.j. geochem. explor., 59, 1126. reimann, c. (1988): comparison of stream sediment and soil sampling for regional exploration in the eastern alps, austria.j. geochem. explor., 31, 75-85. rhoads, b.l & cahill, r.a. (1999): geomorphological assessment of sediment contamination in an urban stream system.appl. geochem., 14, 459-483. rock, n.m.s (1988): numerical geology.lecture notes in earth sciences, vol. 18, springer-verlag, berlin heidelberg new york london paris tokyo, 427 p. rose, a.w., hawkes, h.e. & webb, j.s (1979): geochemistry in mineral exploration.2nd ed., academic press, london, 657 p. salminen, r., tarvainen, t., demetriades, a., duris, m., fordyce, f.m., gregorauskiene, v., kahelin, h., kivisilla, j., klaver, g., klin, h., larson, j.o., lis, j., locutura, j., marsina, k., mjartanova, h., mouvet, c., o’connor, p., odor, l., ottonello, g., paukola, t., plant, j.a., reimann, c., schermann, o., siewers, u., steenfelt, a., van der sluys, j., de vivo, b. & wiliams, l. (1998): foregs geochemical mapping field manual. geological survey of finland, 36 p., espoo. swan, a.r.h. & sandilands, m (1995): introduction to geological data analysis.blackwell science ltd., oxford, london, 442 p. swennen, r. & van der sluys, j. (1998): zn, pb, cu and as distribution patterns in overbank and mediumorder steam sediment samples: their use in exploration and environmental geochemistry.j. geochem. explor., 65, 27-45. swennen, r., van der sluys, j. & brusselmans, a. (1998): geochemistry of overbank and high-order stream sediments in belgium and luxembourg: a way to asses environmental pollution.j. geochem. explor., 62, 67-79. ©iftar, d. (1989): starost evaporita i porijeklo sulfata u rudama kraj zagreba (the age of evaporites and the origin of sulfate at rude near zagreb).geol. vjesnik, 42, 59-64. ©iki∆ k., basch, o. & ©imuni∆, a. (1978): osnovna geoloπka karta sfrj, 1:100.000, list zagreb, l38-80 (basic geological map of sfrj, 1:100.000, the zagreb sheet).institut za geoloπka istraæivanja, zagreb (1972), savezni geoloπki zavod, beograd. ©inkovec, b. (1971): geologija leæiπta æeljezne i bakrene rude u rudama kraj samobora (geology of the iron and copper ore deposit at rude near samobor).geol. vjesnik, 24, 165-181. veli∆, j. (1983): akceleracija vertikalnih tektonskih pokreta tijekom neogena i kvartara u zapadnom dijelu savske depresije (the neotectonic relations and development of the western part of the sava river depression).geol. vjesnik, 36, 225-265. manuscript received february 2, 2000. revised manuscript accepted april 23, 2001. the origin and importance of the dolomite-limestone breccia between the lower and upper cretaceous deposits of the adriatic carbonate platform: an example from ∆iêarija mt. (istria, croatia) igor vlahovi∆ 1, josip ti©ljar 2, ladislav fu»ek1, nenad o©tri∆1, boæo prtoljan 1, ivo veli∆1 and dubravko mati»ec1 1. introduction during the exploratory geological works for the railway tunnel project through the ∆iêarija mt. belt (western croatia fig. 1) special attention was paid to the problem of the complex of dolomite-limestone breccia on the ne flank of the mountain, regarding the position, shape, and origin of the sedimentary body. previously there were two opposing opinions concerning the occurrence and origin of the dolomite-limestone breccia. according to the explanatory notes of the basic geological map, sheet ilirska bistrica (©iki∆ & pleni»ar, 1975) these deposits were formed by erosion of the carbonate rocks during tectonic uplift, and redeposition of the derived coarse-grained material into the basin. the brecciated appearance would therefore represent the consequence of irregular fragmentation of the carbonate rocks during weak synsedimentary movements, which were attributed to the “austrian tectonic phase”. therefore, these breccia deposits were interpreted as intraformational, i.e. deposits which are positioned within the structure between lower cretaceous and upper cretaceous shallow-water platform limestones. the same level of brecciated rocks in the central istria were referred to as “the horizon of the clastic-carbonate rocks”, and interpreted in similar way by pol©ak & ©iki∆ (1973). according to the second, later opinion of some investigators presented in unpublished reports, these deposits would correspond to the so-called jelar breccia, or jelar beds, i.e. a post-cretaceous tectogenic rock-fall breccia covering large areas of velebit mt. and some of the northern adriatic islands. in this case the breccia deposits would represent irregular, lensoid bodies covering palaeodepressions in the more or less tectonized underlying cretaceous deposits therefore, they would not be concordantly inserted within the structure of the ∆iêarija mt., i.e. between the lower and upper cretaceous carbonate deposits. explanation of the problem of structural position and origin of the dolomite-limestone breccia of the geologia croatica 55/1 45 55 10 figs. zagreb 2002 key words: lower to upper cretaceous transition, tectogenic-diagenetic breccia, late-diagenetic dolomitization, late-diagenetic silicification, ∆iêarija mt., adriatic carbonate platform, croatia. 1 institute of geology, sachsova 2, p.o.box 268, hr-10000 zagreb, croatia; e-mail: geologia-croatica@zg.tel.hr 2 faculty of mining, geology & petroleum engineering, university of zagreb, pierottijeva 6, hr-10000 zagreb, croatia. abstract on the ne slopes of ∆iêarija mt. (n istria) a 120-150 m thick complex composed of dolomite-limestone breccia crops out between the lower and upper cretaceous deposits. this studied breccia sequence is of post-sedimentary, tectogenic-diagenetic origin. it was formed by polyphase tectonic fracture of the upper albian to lower cenomanian earlyand late-diagenetic dolomite succession with relics of recrystallized limestone, which enabled very important subsequent diagenetic alteration. this included partial dissolution, dedolomitization, recrystallization and calcitization of the fine-grained, crushed dolomite matrix, and centripetal dissolution of dolomite fragments and their cementation by calcite and ferroan calcite cements, as well as the partial collapse of fragments from the roofs of dissolution cavities and limited late-diagenetic silicification (the silica surplus originating from layers of diagenetic quartz from underlying upper albian deposits). such a complex pattern of different events resulted in the high variability of breccia characteristics over relatively small distances, especially near more intensively tectonized zones. the contemporaneous stratigraphic level (lower to upper cretaceous transition) in other parts of the adriatic carbonate platform is also characterised by predominantly late-diagenetic dolomites with relics of limestones (including local occurrences of early-diagenetic dolomites) which are, in more tectonized areas, late-diagenetically altered into tectogenic-diagenetic breccias. 46 geologia croatica 55/1 ∆iêarija mt. (vlahovi∆ et al., 1995) was a very important issue in the construction of the geological profile of the future tunnel, especially regarding their extremely variable, and more or less unfavourable engi neering-geological properties (biondi∆ et al., 1995). therefore, during the exploratory works detailed investigation of their superficial occurrence, relationship with neighbouring lithostratigraphical units, as well as a complex investigation of their sedimentological, petrographical, palaeontological and stratigraphic properties was performed. the results of these investigations and the completely new interpretation of their origin, as well as a brief regional overview of the transitional level between the lower and upper cretaceous deposits, are the main topics of this paper. 2. the occurrence, lithological properties and stratigraphic position of the investigated breccia 2.1. occurrence of the breccia deposits in the study area breccia deposits occur in the undivided, approximately 1-1.5 km wide zone near the core of an anticline composed mostly of the cretaceous deposits. a similar zone composed of dolomite-limestone breccia is also present in the ne limb of the anticline, in a contemporaneous stratigraphic position between the albian and cenomanian shallow-water limestones (fig. 2). the field observations suggest that these deposits represent part of the structure, i.e. that they are concordant within the upper albian and middle cenomanian limestones. this, together with the need for obtaining as much data as possible concerning their engineeringtechnical properties at the level of the future tunnel, resulted in the location and drilling a 350 m deep well (æt∆-2). the well was located within the area composed of cenomanian limestones dipping at approximately 25° w, and in compliance with the prognosis profile penetrated the breccia deposits at depth between 50.5 to 215.4 m (fig. 3). the well ended in the upper albian deposits (limestones and rarely late-diagenetic dolomites, including three layers of diagenetic quartz deposits equivalent to the contemporaneous deposits in istria and island of vis galovi∆, 1992). contacts between the breccia deposits and underlying albian limestones, as well as the overlying cenomanian deposits are very irregular, both in the well-core and on the surface. generally, all varieties of gradual transitions from completely undisturbed limestones, over more or less intensely cataclastized and late-diagefig. 1 location map showing localities mentioned in the text, study area (black rectangle) and some other occurrences of a similar breccia (grey circles). netically dolomitized limestones, to the typical breccia can be observed in the transitional areas. within the breccia zone there are also frequent lateral changes, especially along the younger fault zones: in the areas further from the tectonic zones cutting the breccia unit, large, more or less well preserved dolomite blocks (in some places even with limestone relics) occur, while near the faults, rocks are completely fractured and brecciated. 2.2. lithological properties the breccia is predominantly composed of dolomite fragments, with variable amounts of limestone relics, authigenous quartz aggregates and mostly calcitic microspar to spar cement (figs. 4 and 5). dolomite fragments are characterised by variegated structural types: besides the most common homogenous crypto to microcrystalline texture some grains show alternation of dolomicritic and dolopelsparitic laminae with relics of cryptalgal lamination, indicating their origin from partially recrystallized early-diagenetic dolomites. fragments exhibit different hues of a grey colour, a commonly obvious consequence of the varying intensity of diagenetic alteration, mostly by recrystallization and dedolomitization. some fragments clearly exhibit their early-diagenetic dolomite origin, while others were formed by stronger or weaker recrystallization of fractured and crushed early-diagenetic dolomites or the complete late-diagenetic dolomitization of former limestones. fragment size is very variable, the most common grains being 1-50 mm in diameter, but in some parts of the breccia zone there are dm-sized fragments, 47vlahoviê et al.: the origin and importance of the dolomite-limestone breccia... fig. 2 simplified geological map of the north-eastern slope of ∆iêarija mt. with the location of well æt∆-2 (on the left). fig. 3 simplified well-log showing subsurface relations of the studied deposits. 48 geologia croatica 55/1 and even blocks a few metres in size. the fragments are more or less isometric, mostly angular with more or less rounded corners. infrequent rounded grains are obviously the result of corrosion and solution of the original rock by aggressive pore solutions and replacement of dolomite by calcite (i.e. dedolomitization), not of rounding during possible transport. corrosional “rounding” of fragments is clearly visible in thin sections, especially by obvious centripetal calcitization, i.e. this process gradually prograded from tectonic fissures surrounding the fragments towards the interior of the grains (fig. 4). fitting (füchtbauer & richter, 1983), i.e. the compatibility of the contours of neighbouring grains, is variable, but relatively high: fragments are commonly divided only by tectonic fissures and joints (similar effects are also present in the underlying rocks fig. 6), which are more or less widened by corrosion (fig. 5). in the more tectonized parts of the study area, characterised by more important dissolution and formation of dissolution pores and caverns, collapsed material within such open spaces is characterised by very low fitting. fitting is also low in tectonic breccias formed along clearly marked tectonic lines. in some places, especially in the vicinity of more tectonized zones, intergranular contacts are frequently stylolitic, i.e. formed as a consequence of subsequent intense pressure solution (fig. 7). quartz aggregates, which macroscopically appear as compact white clasts (fig. 9b; these clasts were occasionally in former investigations even mistaken for white cenomanian limestone clasts!), were formed by selective early-diagenetic silicification of the most unstable carbonate components (mostly dissolved and dedolomitized dolomite fragments, in some places also fig. 4 photomicrograph of diagenetic breccia composed of dolomicrite fragments and calcitized and partly silicified matrix. note “rounding” of fragments due to corrosion of the dolomite fragments. æt∆-2, 180.6 m; stained thin-section, polarised light, photo length = 3.3 mm. fig. 5 photomicrograph of diagenetic breccia with corroded dolomite fragments and completely calcitized fine-crystalline matrix and neocalcite mosaic cement. most of the fragments are still characterised by relatively high fitting. æt∆-2, 73.3 m; stained thin-section, polarised light, photo length = 3.3 mm. 49vlahoviê et al.: the origin and importance of the dolomite-limestone breccia... calcitized fine-grained carbonate matrix). these quartz druses are mostly composed of hypidiomorphic crystals of variable size, which were during the most recent calcitization processes frequently disintegrated by neocalcite growth between quartz aggregates, resulting in formation of isolated quartz “grains” within a calcite mass. quartz crystals frequently exhibit radial growth of the terminal surfaces in the form of rosettes (fig. 8). subsequent calcitization of quartz aggregates is most obvious near numerous irregular tectonic fissures and fractures formed by the youngest tectonic movements (neotectonic phase post-miocene). calcitization is generally clearly centrifugal, resulting in complete calcitization of the inner parts of quartz rosettes. quartz aggregates were formed by in situ growth of quartz crystals during late diagenetic circulation of solutions enriched in silicic acid. the silica surplus probably originated from diagenetic quartz deposits found in the underlying upper albian deposits. the cement and matrix of the dolomite-limestone breccia are mostly composed of microsparitic calcite. this matrix was formed by calcitization (i.e. dedolomitization) of finely crushed dolomicrite, which is present only in the form of small relics, while calcite cement filled the remaining voids. in some places gradual transitions from dolomicrite fragments and partially calcitized dolomicrite to cryptocrystalline calcite with rare dolomicrite relics are visible. significant calcitization occurred in the most tectonically disintegrated areas, i.e. the intensity of calcitization is more or less positively correlatable with the intensity of tectonic disintegration. both cement and matrix are partially recrystallized, and in some parts spelaeothems, formed by the circulation of solutions through corrosionally widened fig. 6 photomicrograph of tectonized albian limestone showing fractures filled by coarse-crystalline calcite cement. note high fitting. æt∆-2, 285.4 m; stained thin-section, polarised light, photo length = 7.5 mm. fig. 7 photomicrograph of stylolitization breccia characterised by stylolitic intergranular contacts formed as a consequence of intense pressure solution. note intense late-diagenetic silicification of two small fragments of dolomicrites in the lower left, subsequently cut by calcite veins. æt∆-2, 121.4 m; stained thin-section, polarised light, photo length = 7.5 mm. 50 geologia croatica 55/1 tectonical fractures, were observed. younger tectonic fractures and some solution cavities are completely cemented by mosaic sparry calcite. 2.3. stratigraphic position no index fossils have been discovered in fragments or matrix of the dolomite-limestone breccia, which is not unusual as they are mostly composed of earlyand latediagenetic dolomites with late-diagenetic calcitized fractures. only in infrequent undolomitized limestone relics have rare miliolids and ostracods been observed, but without any stratigraphic significance. therefore, the stratigraphic position of the studied sequence can only be established on the basis of superpositional relationships. both from surface data and information from drilling it is clear that the studied dolomite-limestone breccia is situated between albian and cenomanian carbonates. the underlying deposits are mostly grey, dark greybrownish to almost black, platy to thin-bedded (≤ 3 0 cm) mudstones, which are, in the upper part, frequently late-diagenetically dolomitized. on the basis of their fossil content (c h a m a sp., gastropods, nubecularids, and benthic foraminifera: praechrysalidina infracreta cea luperto-sinni, pseudonummoloculina heimi (bonet) and other miliolids) and correlation with similar deposits of the neighbouring areas their albian age is certain. however, the geological position of the studied deposits and three levels of diagenetic quartz deposits determined in the æt∆-2 well (at 215.3-217.5, 223.1-223.2 and 244.1-244.3 m), which are regionally important for the latest albian, indicate a probable upper albian age. fig. 8 photomicrograph of partially silicified calcitized matrix (upper right) and a partly dedolomitized dolomicrite fragment (lower left) of diagenetic dolomite-limestone breccia. note that quartz crystals frequently exhibit radial growth of the terminal surfaces in the form of rosettes. æt∆-2, 51.25 m; stained thin-section, polarised light, photo length = 3.3 mm. fig. 9 five typical examples of different varieties of the studied breccia from well æt∆-2. a) completely corroded dolomite fragments (“rounded” grains) surrounded by a large quantity of finely crushed recrystallized matrix; b) large fragments of dolomite “floating” in dark calcitic matrix; c) matrix-rich breccia characterised by intense corrosion (isometric solution vugs formed by dedolomitization); d) breccia composed of completely silicified white fragments and laminated early-diagenetic dolomites; e) fractured dolomite with thin fillings of white calcite between dolomite fragments. 51vlahoviê et al.: the origin and importance of the dolomite-limestone breccia... overlying deposits are represented by brown dark brown, rarely yellowish and grey-brownish, partly recrystallized mudstones to peloid-skeletal wackestones with infrequent rudist debris. radiolitid and ostreid floatstones are relatively rare. in these deposits typical middle to upper cenomanian fossils of the adriatic carbonate platform have been observed: c h r y s a l i d i n a g r a d a t a d’orbigny, nummoloculina regularis p h ilippson, pseudonummoloculina heimi, p s e u d o l i t u o nella reicheli marie, etc. concerning the position of deposits directly overlying the breccia in the study area, the lack of b r o e c k i n a (p a s t r i k e l l a ) b a l c a n i c a c h e rchi et al., a typical index species for the upper part of the middle and upper cenomanian in the neighbouring area (veli∆ & vlahovi∆, 1994), indicates that a middle cenomanian age seems more probable. on the basis of the aforementioned data, it may be concluded that the studied succession of dolomite-limestone breccia is probably of uppermost albian (vraconian) to lower cenomanian age. this determination completely complies with the stratigraphic position of the same or similar deposits (dolomite or dolomitelimestone breccia, recrystallized early and late-diagenetic dolomites, late-diagenetically dolomitized and recrystallized limestones) in other parts of the adriatic carbonate platform in croatia (e.g. eastern part of istria, islands of krk and cres, gorski kotar area) and slovenia (e.g. “massive to indistinctly bedded bituminous dolomitic breccia” of the povir formation in the area of the trieste-komen plateau jurkov©ek et al., 1996), and also in neighbouring italy (tentor et al., 1994). the complete thickness of the studied sequence of dolomite-limestone breccia of the ∆iêarija mt. could be approximated to 130-150 m, on the basis of surface and subsurface data, which is concordant with the estimated thickness of the corresponding level in other areas (e.g. sis formation on the island of cres or povir formation of the trieste-komen plateau jurkov©ek et al., 1996). however, concerning the thickness of this complex it should be emphasised that both boundaries with the overlying and underlying lithostratigraphic units are gradual and irregular as the result of different amounts of tectonic disturbance and selectivity of diagenetic processes; therefore, the thickness of the breccia complex is laterally variable. 3. origin of the dolomite-limestone breccia the origin of the studied rock complex is very complex and polygenetic, as in both the field and in thin-section several genetic types of breccia could be recognised, including different gradual transitions between them. this resulted in great variability of the observed lithofacies, i.e. almost each sample seems at least somewhat different form the others in its close vicinity (fig. 9). all breccia deposits are characterised by the important influence of late-diagenetic processes, which were enabled by intense tectonic disintegration, therefore the entire succession is defined as t e c t o g e n i c d i a g e n e t i c b r e c c i a . however, within the breccia zone there are also spatially restricted occurrences representing relics of breccia deposits of specific origin, also caused more or less directly by recurring intense tectonic activity during post-cretaceous tectonic phases (tertiary tectonic phase and neotectonic phase): a) tectonic breccia; b) stylolitization breccia; c) collapse breccia. tectonic breccias were formed by tectonic disintegration of all rock types (fig. 6), and only occur very close to important faults. therefore, their surficial and subsurface extension is limited. stylolitization brecc i a s were formed by karstification of intensely stylolitized, and subsequently partially cemented dolomites and limestones (fig. 7). both these aforementioned breccia types can also be seen in the underlying and overlying deposits, as well as in other carbonate successions. in the areas of very high dissolution, i.e. near the major zones of circulation, numerous cavities of variable size were formed, and collapse of material from their roofs caused formation of specific type of breccia collapse breccia . this type is characterised by a mixture of different fragments originating from neighbouring beds (which were rotated during their accumulation, therefore resulting in much lower fitting), as well as variable proportions of fragments, finely-crushed matrix and cement filling remaining open spaces. collapse breccias are much more common near major tectonic lines, but are usually also subsequently diagenetically altered. sometimes it is hard to define a borderline between the aforementioned types of breccia and the most complex, and by far the most comprehensive type described in this paper tectogenic-diagenetic breccia . within this breccia type elements of all the other types are encompassed in some places, but they are more or less overprinted by important polyphase diagenetic alterations. therefore, in this paper the term tectogenic-dia genetic breccia is a collective designation for rocks of brecciated appearance formed as a result of the diagenetic alteration of in situ rocks affected by intense tectonics , although in some parts there are still visible traces of a specific major cause of brecciation (i.e. tectonic crushing, collapse of material from the cavity roof or stylolitization). it is important to notice that most of the rocks of this breccia type are characterised by in situ brecciation, i.e. the transport distance of fragments in the breccia is very short (e.g. in the case of collapse origin) or practically absent. 52 geologia croatica 55/1 the original rock succession, before intense postcretaceous tectonic activity, represented the alternation of peritidal early-diagenetic dolomites and limestones. fragments of the early-diagenetic dolomites are commonly characterised by relics of cryptalgal lamination, indicating their formation by early-diagenetic dolomitization in peritidal (supratidal) conditions. interbedded shallow subtidal limestones were subsequently, during the late-diagenetic phase, gradually dolomitized into late-diagenetic dolomite characterised by a mosaic structure composed of hypidiomorphic dolomite crystals. similar successions have been described from the berriasian of istria (“fantazija dolomites” veli∆ & ti©ljar, 1988; ti©ljar et al., 1995) and the upper albian of biokovo mt. (ti©ljar & veli∆, 1991). underlying upper albian deposits and overlying cenomanian deposits were composed of almost pure limestones. this is very important for the origin of the investigated breccia deposits, which resulted from polyphase processes and diagenetic changes which are here, as in other analogous cases, mainly induced by the presence of unit of specific lithology (in this case dolomites) surrounded by rocks of a different composition (in this case predominantly limestones, including infrequent layers of diagenetic quartz in the underlying succession). during the tertiary, the entire sequence of deposits in the study area was affected by quite intense post-sedimentary tectonics (this is the area characterised by the “collision” of istria and its hinterland, resulting in the formation of the ∆iêarija mt. belt, as well as by intense neotectonic deformation). however, concerning the fact that the dolomite rocks are much more prone to tectonic disintegration than limestones (handin & hager, 1957), it is not unusual that the alternation of early-diagenetic and late-diagenetic dolomites was even more intensely fractured than the surrounding albian and cenomanian limestones. in zones near major faults they were even completely crushed, resulting in their greatly enhanced permeability. further diagenetic changes took place under conditions where limestone represented the stable and dolomite the unstable phase. highly fractured and permeable dolomite rocks enabled circulation of chemically aggressive pore solutions causing partial dissolution and/or diagenetic changes of the rock fragments, since these solutions were oversaturated with respect to calcite and undersaturated in respect of dolomite. such a chemical composition of pore waters, i.e. relatively high concentration of calcium hydrogencarbonate, resulted from the intense pressure solution of a thick sequence of mesozoic deposits (predominantly limestones) during the phases of tectonic stress, as well as dissolution of the surficial part of deposits by meteoric waters enriched in co2. relatively aggressive pore solutions caused partial dissolution of dolomite rocks and important allochemical late-diagenetic processes, i.e. calcitization (dedolomitization) and late-diagenetic silicification, which were accelerated by the relatively large reactive surfaces of tectonically disintegrated dolomites, resulting in important changes of mineral and chemical composition of the original rocks. dissolution of dolomite rock along the tectonic fissures and joints caused formation of corrosional voids of varying size, significant widening of fissures and joints, as well as corrosion of surfaces and corners of dolomite fragments (therefore, in zones of intense circulation many “grains” are more or less rounded, which was formerly misinterpreted as a result of rounding of coarse-grained material during transport). recrystallization of the matrix and cementation of neomorphic calcite crystals in open spaces, fissures and fractures as a result of oversaturation of pore solutions in respect to calcium carbonate was a very important diagenetic process. this was followed by gradual replacement of dolomite by calcite, i.e. dedolomitization, which was especially important in the more intensely tectonized zones, resulting in further “rounding” of fragments. calcitization was a polyphase process, as there are several generations of neocalcite of different composition (from calcite to ferroan calcite) caused by polyphase tectonics and variable chemical composition of pore solutions. another important allochemic diagenetic process, although of much lesser extent, was the late-diagenetic silicification of dolomites and dedolomites, and also neocalcite forming the matrix and cement. solutions comprising sio2 diluted in the form of silicic acid gradually replaced carbonate minerals that were unstable under weakly acid ph conditions. silicification resulted in the formation of microcrystalline, rarely even cryptocrystalline quartz aggregates, commonly within the contours of the dolomite fragments or within the calcitized matrix. silicification was obviously a later process than the main calcitization phase, but it is evident that there was at least one subsequent phase of calcite crystallisation. the most probable source of the silica surplus was the underlying diagenetic quartz beds of upper albian age found in the æt∆-2 well. these were formed by late-diagenetic silicification of lagoonal limestones caused by the aeolian input of volcanic ash. this is also why silicification is more intense in the lower part of the studied breccias. 4. discussion and conclusion carbonate breccias are deposits that are quite underestimated in the sedimentological literature. there are several reasons for this, but probably the most important one is their complexity caused by the very common presence of different genetic types at the same locality. furthermore, breccias are often subsequently considerably modified either by tectonics or diagenetic processes, disabling the possibility of direct determination of 53vlahoviê et al.: the origin and importance of the dolomite-limestone breccia... their origin. this results in a common problem in the general perception of breccia: either their mystification (unfortunately, commonly resulting in their complete omission from discussions) or their extreme simplification (placing all types together and suggesting that their origin is already well-known), despite their importance for the appropriate determination of specific events in the geological history of many areas. the transitional level between the lower and upper cretaceous, i.e. upper albian and lower cenomanian deposits, is in most parts of the adriatic carbonate platform characterised by intense dolomitization and recrystallization of limestone relics. at many locations it is obvious that the surplus of magnesium necessary for the massive late diagenetic dolomitization of limestones was provided by early-diagenetic dolomites, as a consequence of the formation of extensive tidal flats during relative sea-level fall. this is the reason why this level is one of those regionally recognised for profound dolomitization. however, dolomite-carbonate breccias are present only in some places, e.g. ∆iêarija mt., hinterland of rijeka, parts of se istria, parts of cres and krk island, etc. why are they absent in other areas? the case of the ∆iêarija mt. dolomite-limestone breccia clearly indicates two substantial prerequisites for the formation of this type of breccia: (1) presence of rocks of specific lithology, different from neighbouring units, (2) their occurrence within zones of intense tectonic activity. only the appropriate combination of both factors enabled the intense disintegration of rocks and significant influence of polyphase complex diagenetic processes. this is the main reason why the amount of tectogenic-diagenetic alterations is laterally extremely variable: even intense tectonic activity will result only in limited changes in successions composed of similar lithologies (since there will be no major allochemical diagenetic changes necessary for the formation of this kind of brecciated rocks) and vice versa: without tectonic disintegration even the successions of completely different lithology than neighbouring units will remain almost unchanged (since diagenetic processes will be much slower and of lesser extent). on the basis of the occurrence of dolomite-limestone breccias of ∆iêarija mt., their composition and structural-textural characteristics, as well as the complex tectonic and diagenetic processes relevant to their formation the following main conclusions may be drawn: 1) these rocks are not sedimentary, intrabasinal breccias formed by synsedimentary tectonic phases between the lower and middle cretaceous; 2) the investigated sequence of breccia deposits represent a continuous succession located within the structure of ∆iêarija mt. between the upper albian and middle to upper cenomanian deposits, i.e. they are not equivalent to a tectogenous rock fall breccia of the jelar type (cenozoic breccia covering large areas of velebit mt. and some of the northern adriatic islands bahun, 1974); 3) the studied sequence represents rocks of specific properties and origin, formed by complex tectonic and diagenetic processes affecting a specific lithological succession different from neighbouring units besides other specific breccia types recognised within the studied sequence, most of the rocks could be referred to as post-sedimentary tectogenic-diagenetic breccia formed in situ. this kind of genetic interpretation is also partly or completely applicable for breccias from some other stratigraphic levels in the adriatic carbonate platform realm, although these sequences are not so thick and outcrops of similar rocks are not so extensive. in these cases the interrelation of intense tectonics and specific lithologies is also obvious, as in the area of mala kapela mt. where good examples of neocomian tectogenicdiagenetic dolomite breccia can be found (fig. 10). very similar, although resulting from the completely opposite process (late-diagenetic dolomitization of calcite along tectonic fractures), breccias were described in the malm deposits of the velebit mt. (ti©ljar, 1990). the correct genetic interpretation of breccia deposits is extremely important for the sedimentological, tectonic and palaeogeographic interpretation of the wider region (ti©ljar, 2001). in the case of ∆iêarija mt. erroneous substitution of this type of breccia with synsedimentary ones, or their erroneous interpretation as younger, rock-fall breccias forming lens-shaped bodies only in near-surface zone, would be extremely critical. this is not purely a scientific question: in this case the interpretation of a large part of the geological profile for the planned tunnel through ∆iêarija mt. have to be based on the right conclusion, especially concerning possible serious problems during drilling of the studied complex. 5. references bahun, s. (1974): tektogeneza velebita i postanak jelarnaslaga (the tectogenesis of mt. velebit and the formation of jelar deposits).geol. vjesnik, 27, 35-51. biondi∆, b., braun, k., vlahovi∆, i., mlinar, æ., andri∆, m., balen, i., pollak, d., fu»ek, l., o©tri∆, n., prtoljan, b., ©aban, b., blagus, z., dukari∆, f., buljan, r. & biondi∆, r. (1995): inæenjerskogeoloπki model æeljezniëkog tunela ∆iêarija (engineering-geological model of the railway tunnel “∆iêarija”).in: vlahovi∆, i., veli∆, i. & ©parica, m. (eds.): 1. hrvatski geoloπki kongres (first croatian geological congress), zbornik radova (proceedings), 1, 81-87, zagreb. füchtbauer, h. & richter, d.k. (1983): relations between submarine fissures, internal breccias and mass 54 geologia croatica 55/1 flows during triassic and earlier rifting periods.geol. rundschau, 72/1, 53-66. galovi∆, i. (1992): geoloπki poloæaj i geneza kvarcnih sedimenata istre.unpublished phd thesis (in croatian with an english abstract), university of zagreb, 120 p. handin, j. & hager, r.v. (1957): experimental deformation of sedimentary rocks under confining pressure.bull. am. assoc. petrol. geol., 41, 1-50, (and 42, 2897-2934). jurkov©ek, b., toman, m., ogorelec, b., ©ribar, l., drobne, k., poljak, m. & ©ribar, lj. (1996): formacijska geoloπka karta juænega dela træaπko-komenske planote 1:50000. kredne in paleogenske karbonatne kamnine (geological map of the southern part of the trieste-komen plateau. cretaceous and paleogene carbonate rocks).inπtitut za geologijo, geotehniko in geofiziko, 143 p., ljubljana. pol©ak, a. & ©iki∆, d. (1973): osnovna geoloπka karta sfrj 1:100.000, tumaë za list rovinj l33-100 (geology of rovinj sheet).institut za geoloπka istraæivanja zagreb (1963), savezni geoloπki zavod, 51 p., beograd. ©iki∆, d. & pleni»ar, m. (1973): osnovna geoloπka karta sfrj 1:100.000, tumaë za list ilirska bistrica l33-89 (geology of ilirska bistrica sheet).institut za geoloπka istraæivanja zagreb & geoloπki zavod ljubljana (1967), savezni geoloπki zavod, 50 p., beograd. tentor, m., tunis, g. & venturini, s. (1994): schema stratigrafico e tettonico del carso insontino.natura nascosta, 9, 1-32, monfalcone. ti©ljar, j. (1990): postsedimentne dolomitizacijske breëe u jurskim plitkomorskim karbonatnim sedimentima malog halana na juænom velebitu (postsedimentary dolomitization breccias in the jurassic shallow-marine carbonate sediments of the mali halan southern velebit mt.).rudarsko-geoloπko-naftni zbornik, 2, 59-65, zagreb. ti©ljar, j. (2001): sedimentologija karbonata i evaporita.institute of geology, zagreb, 375 p. ti©ljar, j. & veli∆, i. (1991): carbonate facies and depositional environments of the jurassic and lower cretaceous of the coastal dinarides (croatia).geol. vjesnik, 44, 215-234. ti©ljar, j., vlahovi∆, i., mati»ec, d. & veli∆, i. (1995): platformni facijesi od gornjeg titona do gornjega alba u zapadnoj istri i prijelaz u tempestitne, klinoformne i rudistne biolititne facijese donjega cenomana u juænoj istri (ekskurzija b) (platform facies from the upper tithonian to upper albian in western istria and transition into tempestite, clinoform and rudist biolithite facies of the lower cenomanian in southern istria (excursion b)).in: vlahovi∆, i. & veli∆, i. (eds.): 1. hrvatski geoloπki kongres (first croatian geological congress), vodië ekskurzija (excursion guide-book), 67-110, zagreb. fig. 10 photograph of the outcrop of neocomian tectogenic-diagenetic dolomite breccia on the mala kapela mt. coin is 27 mm in diameter. a) tectogenic-diagenetic breccia characterised by different amounts of diagenetic alteration of the original dolomite rock. tectonic fissures are filled with white calcite cement. the lower part of the photograph represents completely crushed dolomite with only small “rounded” relics of the original rock. b) detail of the upper right part of fig. 10a showing more intensely tectonized part of the outcrop, characterised by a large amount of white calcitized matrix and still relatively high fitting of dolomite fragments. 55vlahoviê et al.: the origin and importance of the dolomite-limestone breccia... veli∆, i. & ti©ljar, j. (1988): litostratigrafske jedinice u dogeru i malmu zapadne istre (zapadna hrvatska, jugoslavija).geol. vjesnik, 41, 25-49. veli∆, i. & vlahovi∆, i. (1994): foraminiferal assemblages in the cenomanian of the buzet-savudrija area (northwestern istria, croatia).geologia croatica, 47/1, 25-43. vlahovi∆, i., ti©ljar, j., veli∆, i., fu»ek, l., o©tri∆, n. & prtoljan, b. (1995): o podrijetlu i znaëenju tzv. vapnenaëko-dolomitnih breëa izmeu donje i gornje krede: primjer ∆iêarije (on the origin and significance of the limestone-dolomite breccia between the lower and upper cretaceous: an example of ∆iêarija).in: vlahovi∆, i., veli∆, i. & ©parica, m. (eds.): 1. hrvatski geoloπki kongres (first croatian geological congress), knjiga saæetaka (abstracts), 99, zagreb. manuscript received june 18, 2001. revised manuscript accepted may 20, 2002. 56 geologia croatica 55/1 juracic et al.indd 1. introduction the central part of the adriatic sea is situated between the western coast of croatia and the eastern italian coast, and its shape is characterised by the surrounding alpine mountains. two mountain chains, the apennines and the dinarides, mark its edges, predetermine its nature, and separate it from the western mediterranean, and from the eastern alps and the pannonian basin, respectively. in the adriatic sea area, occurrences of igneous rocks are exceptionally rare at the surface but have been observed since the 18th century (donati, 1750) and recognised since the end of the 19th century and later (hauer, 1882; kišpatić, 1892; tućan, 1953; barić, 1961; golub & vragović, 1975; balogh et al., 1994). the igneous rocks from the western part of vis island were classified as augiteporphyry and melaphyre (hauer & stache, 1862). carella (1961) named them augite-andesite and augite basalt. golub & vragović (1975) determined them as extrusive types with augite-andesite, spilite-keratophyre and spilite. in contrast, the rocks that form the entire brusnik and jabuka islets, to the west of vis island are regarded as intrusive rocks because of their texture and were classified as augitediorite (foullon, 1883), and diorite (pelleri, 1942). kišpatić (1892) and raffaelli (1977) jabuka shoal, a new location with igneous rocks in the adriatic sea mladen juračić1, anđelko novosel2, darko tibljaš1 and dražen balen1 found diabasic texture in these rocks and named them diabase and quartz-diabase. golub & vragović (1975) considered them to be subvolcanic augite-diabase, vrkljan (1979) named the jabuka islet rocks as augite diabase and spilitized augite diabase, whereas balogh et al. (1994) as medium-grained gabbro. recently, garašić et al. (2001), described dolerite from the islet of brusnik. the main difference between rocks found on the jabuka and brusnik islets is in their appearance. jabuka islet is probably a core of a small magmatic body while brusnik islet is partially built up of conglomerate with pebbles up to 50 cm in diameter (crnjaković, 1998). the radiometric ages (k–ar 215–200 ma, and ar–ar 200 ma) measured on gabbro from jabuka islet reflects the latest stage of crystallization after the intrusion, since negligible rejuvenating processes due to synand postmagmatic hot fluids circulation have been inferred (balogh et al., 1994). this age corresponds to the triassic–jurassic boundary and could be interpreted as a late stage of rift-related magmatism. the aim of this paper is to present a new locality with igneous rocks in the adriatic sea, provide basic petrographic and geochemical data, and discuss their significance. 2. results and discussion nautical maps reveal few shoals in the region near to the jabuka and brusnik islets and we presumed that some of the shoals might also have igneous rocks. research in the summer of 2001 concentrated on the shoal approximately 2300 m wnw of jabuka islet, as indicated/mapped on the coastal chart (hhi, 2000) 100–22 jabuka–vis, scale 1:100,000. the location of the jabuka shoal is 43°06’06”n, 15°26’21”e. the top of the shoal is located 6 m below sea level. its location and relationship to other islands in the region is presented in fig. 1 (after hhi, 1980). no precise map of the jabuka shoal exists. in order to locate sampling points the jabuka shoal was measured and a sketch of the top of the shoal was produced (fig. 2a and b). transects where rock sampling was performed, at different depths on the flanks (“cliffs”) are also presented. a large part of the shoal is covered with algae (fucus) and it was rather difficult to sample the source rock. in appearance it is interesting geologia croatica 57/1 81–85 5 figs. 1 tab. zagreb 2004 key words: gabbro, magmatism, fault zone, jabuka shoal, adriatic sea, dinarides, croatia. 1 university of zagreb, faculty of science, department of geology, p.o.box 332, hr-10002 zagreb, croatia; e-mail: mjuracic@geol.pmf.hr 2 institute of geology, sachsova 2, hr-10000 zagreb, croatia. abstract petrographic and xrf analyses of the magmatic rock from jabuka shoal, 2300 m west of jabuka islet (central adriatic sea) revealed that the rock is gabbro. this new location of magmatic rocks in the adriatic confirms their linear arrangement, and indicates the presence of an important fault line which predisposed the occurrences of magmatic rocks. 82 geologia croatica 57/1 83juračić, novosel, tibljaš & balen: jabuka shoal, a new location with igneous rocks... that at the jabuka shoal a massive (monolithic rock) along with cobbles and pebbles (conglomerate) is present, a combination of the way the rock appears at brusnik islet. 2.1. petrography samples from jabuka shoal (fig. 3) are mostly mediumgrained rocks of hypidiomorphic holocrystalline texture having a massive structure. however, some portions of rock characteristically resemble ophitic texture while other parts rarely contain spherulites, amygdales and fissures, filled with non-oriented needles of prehnite. their mineral composition comprises clinopyroxenes and plagioclase, with subordinate amphibole (uralite), chlorite and opâque minerals. the most common mafic minerals are clinopyroxenes (pale green and brown monoclinic pyroxene). the first one is slightly zoned and shows weak pale green pleochroism. the distribution of fine-grained opâque minerals marks zoning in the clinopyroxene. uralitization altered clinopyroxene and produced secondary green amphibole. in these mineral aggregates chlorite is also present as a product of a later alteration process. the plagioclase commonly displays weak zoning with a more basic core and an acidic rim. usually plagioclase contains sericite flakes and non-oriented opâque mineral inclusions (poikilitic texture). also it shows polysynthetic twins. accessories are opâque mineral(s) and apatite. all of the primary minerals are altered to various degrees. in spite of the fact that the rock suffered changes up to prehnite–pumpellyite facies, the presence of small amounts of newly-formed minerals mean that the rock is still determined as gabbro. petrographic data reveal that the samples from jabuka shoal have similar structural, textural and compositional features compared to the ~2 km distant jabuka islet as described in detail in balogh et al. (1994). 2.2. geochemistry major and trace element contents of rock sample pj 2/18 from the jabuka shoal, analyzed by the xrf method in the activation laboratories ltd., canada, along with a sample from jabuka islet (ja01/4) and data from balogh et al. (1994) and from golub & vragović (1975) are given in table 1. the low content of mgo (3.49 wt. %), low magnesium number (41.0) and also the low content of ni and cr (8, <5 ppm, respectively) show that the magma was not primitive in its nature. fig. 1 location of the jabuka shoal and jabuka islet in the adriatic sea. after nautical chart 300–33 pescara–split (hhi, 1980). 82 geologia croatica 57/1 83juračić, novosel, tibljaš & balen: jabuka shoal, a new location with igneous rocks... the major element content of jabuka shoal rocks is similar with those of the nearby jabuka islet magmatic rocks. figure 4 – tas classification diagram (le bas et al., 1992) shows that both the jabuka shoal and the jabuka islet rock samples plot in a relatively narrow area overlapping the basaltic andesite and basaltic trachyandesite fields. the trace elements distribution reflects the major element content. a diagram after winchester & floyd (1977) based on immobile trace elements (fig. 5) shows that the samples chemically correspond to the basalt/ andesite field. the presented results indicate that magmatic melts moved upwards along fractures into the overlying continental crust. in the newly formed “magma chambers”, various differentiation and crystallization processes took place and finally produced gabbro. the position of three known localities (jabuka, brusnik and komiža) together with the new jabuka shoal occurrence, 2300 m west of the jabuka islet, show a linear arrangement that can be set up as a superficial marker of fault system(s) which predisposed the occurrences of the magmatic rocks. 3. conclusion the main contribution of this research and the discovery of magmatic rocks on the jabuka shoal is that the linear arrangement indicates a structure connecting the jabuka shoal, jabuka and brusnik islets and komiža. they may be regarded as an important superficial marker of a fault system(s) which predisposed the occurrences of magmatic rocks. fig. 2 (a) sketch of the top of the jabuka shoal with transect locations pj1 and pj2; depths in m; (b) schematic transects with sampling locations. fig. 3 detail of gabbro texture – pyroxene (cpx) and plagioclase (pl) grains with alteration products; sample pj2 jabuka shoal, depth 18 m, plane polarized light, crossed polars, picture width 1.6 mm. a b 84 geologia croatica 57/1 85juračić, novosel, tibljaš & balen: jabuka shoal, a new location with igneous rocks... sample pj2/18 ja–01/4 ja–bal ja–gv1 ja–gv2 ja–gv3 ja–gv4 ja–gv5 sio2 52.15 52.49 50.60 51.63 52.48 51.88 51.50 53.62 tio2 0.84 0.94 1.14 1.71 2.27 2.08 1.40 1.67 al2o3 17.18 17.06 14.76 17.12 15.88 12.58 17.68 13.30 fe2o3 9.95 10.63 13.80 4.26 6.69 9.55 3.94 7.06 feo 0.00 0.00 0.00 5.07 4.52 4.78 7.12 6.37 mno 0.13 0.19 0.20 0.06 0.05 0.13 0.16 0.11 mgo 3.49 3.36 5.34 3.83 1.44 4.70 3.31 3.28 cao 7.27 7.67 7.51 8.42 8.03 7.61 7.71 5.18 na2o 5.22 3.35 2.95 4.21 5.42 2.87 3.30 6.48 k2o 1.17 1.66 1.21 1.43 1.27 0.85 1.45 0.22 p2o5 0.18 0.20 0.18 0.15 0.25 0.20 0.18 0.36 h2o 2.54 2.53 2.32 2.12 2.06 2.53 2.32 2.28 total 100.12 100.08 100.01 100.01 100.36 99.76 100.07 99.93 mg # 41.0 38.5 43.4 43.4 19.6 38.5 35.6 31.5 ba 267 338 323 ce 0 0 26 co 25 27 0 cr <5 <5 63 cu 107 106 241 ga 18 19 0 la 0 0 14 nb 3 2 4 nd 0 0 14 ni 8 10 16 rb 28 51 29 sc 0 0 38 sr 250 336 336 v 199 227 256 y 23 23 23 zn 41 63 238 zr 77 76 77 table 1 major (wt. %) and trace (ppm) elements for the jabuka shoal (pj) and islet (ja) samples; bal – balogh et al. (1994); gv – golub & vragović (1975). mg # = 100*molar mgo/(mgo+feotot). fig. 4 segment of the total alkali–silica (tas) classification diagram (le bas et al., 1992) for igneous rocks of the jabuka shoal and jabuka islet (central adriatic sea): empty circle – jabuka shoal; full circle – jabuka islet, this work; full square – jabuka islet, balogh et al. (1994); empty square – jabuka islet, golub & vragović (1975). numbers on diagram: 1 – basaltic andesite; 2 – basaltic trachyandesite. fig. 5 plot of zr/tio2 against nb/y (winchester & floyd, 1977) for igneous rocks of jabuka shoal and jabuka islet (central adriatic sea): empty circle – jabuka shoal; full circle – jabuka islet, this work; full square – jabuka islet, balogh et al. (1994); 1 – range of andesite/basalt. 84 geologia croatica 57/1 85juračić, novosel, tibljaš & balen: jabuka shoal, a new location with igneous rocks... 4. references barić, lj. (1961): wo kommen auf den südund mitteldalmatinischen inseln die eruptivgesteine vor? [where igneous rocks come on southand middle dalmatian islands? – in german].– iii kongres geologa jugoslavije, 1, 343–355, titograd. balogh, k., colantoni, p., guerrera, f., majer, v., ravasz-baranyai, l., renzulli, a., veneri, f. & alberini, c. (1994): the medium-grained gabbro of the jabuka islet (“scoglio del pomo”, adriatic sea).– giornale di geologia, ser. 3a, 56/2, 13–25, bologna. carella, r. (1961): nuove osservazioni sull’isola di lissa (vis) in jugoslavia [new observations on vis island in yugoslavia – in italian].– boll. soc. geol. ital., 80, 27–37. crnjaković, m. (1998): vulkani na jadranskim otocima? [volcanoes on the adriatic islands? – in croatian].– hrvatski prirodoslovni muzej, 40 p., zagreb. donati, v. (1750): della storia naturale marina dell’adriatico [natural history of the adriatic sea – in italian].– appresso francesco storti, 81 p., venezia. foullon, h. (1883): der augitdiorit des scoglio pomo in dalmatien [the augitdiorite of jabuka islet in dalmatia – in german].– verhandl. der k.k. geol. r.-a., 1883, wien, 283–286. garašić, v., vrkljan, m., tadej, n. & majer, v. (2001): dolerites from the islet of brusnik (adriatic sea, croatia).– berichte der deutschen mineralogischen gesellschaft, beih. z. eur. j. mineral., 13/1, 56. golub, l. & vragović, m. (1975): eruptivne stijene dalmatinskih otoka (vis, jabuka i brusnik) [igneous rocks of the dalmatian islands (vis, jabuka and brusnik) – in croatian].– acta geologica, 8/4, 19–63, zagreb. hauer, f. (1882): der scoglio brusnik bei st. andrea in dalmatien [brusnik islet near sv. andrija island in dalmatia – in german].– verhandl. der k.k. geol. r.-a., 1882, wien, 75–77. hauer, f. & stache g. (1862): aufnahmreise in dalmatien [prospection in dalmatia – in german].– verhandl. der k.k. geol. r.-a., 1861 und 1862, wien, 257 p. hhi (1980): nautical chart 300–33, pescara–split, scale 1:300000.– hrvatski hidrografski institut, split. hhi (2000): coastal chart 100–22, jabuka–vis, scale 1:100000.– hrvatski hidrografski institut, split. kišpatić, m. (1892): eruptivno kamenje u dalmaciji [igneous rocks in dalmatia – in croatian].– rad jazu, 111/15, zagreb, 158–190. le bas, m.j., le maitre, r.w. & wooley, a.r. (1992): the consideration of the total alkali–silica classification of volcanic rocks.– mineral. petrology, 46, 1–22. pelleri, l.c. (1942): sulle rocce dioritiche degli scogli pomo e mellisello nel mare adriatico [about diorite rocks of jabuka and brusnik islets – in italian].– per. mineral., 13/2, 191–199. raffaelli, p. (1977): osnovna geološka karta sfrj 1:100.000. tumač za list jabuka k33–31 (basic geological map sfrj 1:100 000. geology of the jabuka sheet k33–31).– institut za geološka istraživanja zagreb (1968), savezni geološki zavod, beograd, 63–67. tućan, f. (1953): o istraživanju eruptivnih stijena otoka jabuke, brusnika i visa [about research on igneous rocks from jabuka, brusnik and vis islands – in croatian].– ljetopis jazu, 57, 215–225, zagreb. vrkljan, m. (1979): neki mikroelementi u eruptivnim stijenama dalmatinskih otoka [some trace elements in igneous rocks of the dalmatian islands – in croatian].– geol. vjesnik, 31, 309–314. winchester, j.a. & floyd, p.a. (1977): geochemical discrimination of different magma series and their differentiation products using immobile elements.– chemical geology, 20, 325–343. manuscript received july 29, 2003. revised manuscript accepted may 04, 2004. 86 geologia croatica 57/1 geo.cro.2-3-61-kb.pdf 177 � carles martín-closas1, jean-paul colin2, jean-paul billon-bruyat3, abder el-albani4, jean-michel mazin5 and johann schnyder6 ab stra ct a charophyte assemblage including latochara tenuicostata (peck 1937) and mesochara gr. voluta (peck 1937) was found in the lower tithonian bone-bed 148 of the stratigraphic section at the pointe de chassiron, oléron island (charente-maritime, southwestern france). this bed, which is well known for its rich and diverse fauna of tetrapods, was deposited in a margino-littoral environment of purbeckian facies in the late jurassic charente palaeogulf. the occurrence of latochara at oléron island is the most southern location known in the distribution of this genus during the late jurassic. this suggests that the boundary between the charophyte boreal and tethyan provinces, defi ned on the basis of this distribution, is not solely determined by latitudinal (i.e. thermal) factors. ecological factors such as salinity and competition with other charophyte families are hypothesized as alternative explanations. keywor ds: charophytes, ostracods, vertebrates, tithonian, france, bioprovinces 1 departament d’estratigrafi a, paleontologia i geociències marines, facultat de geologia, universitat de barcelona, carrer de martí i franqu’s, 08028 barcelona, catalonia, spain; (cmartinclosas@ub.edu) 2 3 impasse des biroulayres, 33610 cestas, france 3 section d’archéologie et paléontologie, offi ce de la culture, république et canton du jura, hôtel des halles, 2900 porrentruy, switzerland 4 umr 6531 hydrasa, ufr sfa bâtiment sciences naturelles, université de poitiers, 40 avenue du recteur pineau, 86022 poitiers cedex, france 5 umr 5125 peps cnrs, france; université lyon 1, campus de la doua, bt. géode, 69622 villeurbanne cedex, france 6 upmc-université paris 06, cnrs, umr tectonique, case 117, 4, pl. jussieu, 75005 paris, france palaeobiogeography of the genus latochara (fossil charophyta) in the upper jurassic of southern europe. new data from oléron island (france) geologia croatica 61/2–3 177–184 3 figs. zagreb 2008 geologia croaticageologia croatica � 1. introduction palaeobiogeography of late jurassic and early cretaceous charophytes is a relatively new and poorly understood subject in charophyte research. the pioneer studies of sirna (1968) and palamarev (1971) on early cretaceous clavatoraceans, showed for the fi rst time that large palaeogeographic regions shared a similar charophyte fl ora, which was useful not only for characterising them biogeographically, but also for large-scale biostratigraphic correlation. late jurassic cha rophyte biogeography of the northern hemisphere, (europe and north america), was characterized by schudack (1996) and schudack et al. (1998). these studies were signifi cant in showing that fl oras from north america and northern europe were much more like each other than like fl oras of the tethyan domain. thus, without calling them bioprovinces, schudack et al. (1998) characterized two different regions on the basis of late jurassic charophyte assemblages. a northern or boreal region was determined with characean-porocharacean fl oras in opposition to a southern or tethyan region, dominated at that time by clavatoracean fl oras. the genus geologia croatica geologia croatica 61/2–3 178 m thick, is late kimmeridgian (biozone autissiodorensis) to early tithonian (biozone gigas) in age (hantzpergue, 1989; hantzpergue et al., 2004). a sequence boundary associated with a drop in sea-level is found at the top of the previous limestone-dominated succession and is marked by a conglomerate 50 cm thick, showing at the top, an accumulation of large woody remains (fig. 1). upon this boundary bed, a purbeckian succession, 56 m thick, developed with non-marine lutites dominating in the lower and upper members, whilst marine carbonates are characteristic of the central member. bioclasts accumulated in particular horizons. the top of the section includes one gypsum layer. sedimentological evidence and the occurrence of layers with marine fossils, such as benthic foraminifera, marine ostracods, echinoderm debris and brachiopod-rich horizons, alternating with other layers rich in charophytes and non-marine ostracods, indicate that this succession was formed in a shallow marine, littoral context infl uenced by freshwater discharges (bousquet, 1967; schnyder, 2003). the age of the fi gu re 1: the studied locality and stratigraphic section at the pointe de chassiron (oléron island, southwestern france) with the charophyte bearing bed (bed 148) indicated. latochara was considered as a key taxon of the northern re gion. furthermore, the boundary between both regions was set at the 20°c isotherm of mean winter temperature. later studies show ed that even in the northern part of the iberian pa laeoisland, tithonian charophyte assemblages lacked this genus and were instead dominated by clavatoracean genera such as globator and clavator (hernández et al., 1999; martín -closas, 2000). this suggested that the 20°c iso therm could be a real late jurassic bioprovincial boundary. now, the occurrence of the marker of the northern province, (the genus latochara), south of the boundary, raises the question of whether factors other than thermal boundaries should be taken into account if we are to understand charophyte palaeobiogeography. 2. geological and palaeontological setting 2.1. geological background the beginning of the uppermost jurassic is generally represented in western europe by a major drop in relative sea level. thus, the epicontinental marine deposits of the lowermost upper jurassic are covered by lagoonal to non-marine facies, including evaporites that develop well into the lower cretaceous (jacquin et al., 1998; rusciadelli, 1999). these facies are generally referred to as “purbeckian”, through com parison with reference-sections in england. in france, the charente basin is one such purbeckian basin that is rich in evaporites. the palaeogeography of this basin shows a narrow gulf opening to the west according to delfaud & gottis (1966) and hantzpergue & lafaurie (1994). this hypothesis has been challenged by a recent palaeogeographic reconstruction by thierry (2000), showing a connection southward and eastward between the aquitanian basin and the mediterranean tethys. the outcrops are located in the northern part of oléron island, along the cliffs of the pointe de chassiron, near the chassiron lighthouse (fig. 1). this section represents the most complete stratigraphic record of the purbeckian basin of the charentes. in particular, it is an excellent outcrop of the boundary between the underlying upper jurassic marine rocks and the purbeckian non-marine facies. the stratigraphy and biostratigraphy of the section were studied in detail by lantz (1958), donze (1960), malz (1958, 1966) and bousquet (1967), who provided a de tail ed sedimentological study and bourgueil et al. (1976). more recently, hantzpergue (1989) and hantzpergue et al. (2004) reported new biostratigraphic data and schnyder (2003) proposed a new palaeoclimatic interpretation based on palynological and mineralogical evidence. 2.2. description of the stratigraphic section at pointe de chassiron the base of the section consists of grey-beige limestones (mud stone to bioclastic packstone), showing poorly stratifi ed or irregular, nodular bedding, alternating with marls (fig. 1). in sedimentological and palaeontological terms, the facies correspond to a shallow, open platform of normal salinity, with ammonites, echinoderms and dinofl agellates (bousquet, 1967; schnyder, 2003). this succession which is up to 24 geologia croaticacarles martín-closas et al.: palaeobiogeography of the genus latochara (fossil charophyta) in the upper jurassic of southern europe... 179 purbeckian succession is not easy to establish in the absence of ammonites. however, an early to late tithonian age was suggested on the basis of ostracods, brachiopods (hantzpergue et al., 2004), calcareous nannofossils and dinofl agellates (schnyder, 2003). bed 148, which provided the fossils that are the subject of this study, is a marl with small carbonaceous nodules, lo cat ed in the lower part of the purbeckian succession, upon a greenish marly-silty layer (fig. 1). it shows an accumulation of woody remains at the base, charophyte gyrogonites and vertebrate remains. the member of the section containing this layer was attributed to the early to middle tithonian. this member is formed by dark blue marly claystones interlayered with siltstones and silty, fi nely bedded limestone. these rocks are thought to have been deposited in a littoral or estuarine bay with abundant freshwater discharges. the lack of fauna indicating normal marine salinity such as echinoderms is of particular interest and, in contrast, the presence of rare ostracods of the “cypris” type, indicates brackish to freshwater conditions, together with charophytes (bousquet, 1967; schnyder, 2003). 2.3. the fauna associated with charophytes two main groups of fossils were found associated with the charophytes studied: ostracods and vertebrates. ostracods are represented by about 20 species. the euryaline form fabanella boloniensis ornata (steghaus, 1953) and the limnic genus mantelliana cf. perlata wienholz, 1968 are dominant. the remaining fauna consists mainly of non-marine species: cetacella armata martin, 1958, darwinula oblonga (roemer, 1839), alicenula leguminella (forbes in lyell 1855) the rio synoecum aff. forbesii (jones, 1885), theriosynoecum cf. albertense (pinto & sanguinetti, 1962), cypridea spp., eo paracypris sp., stenestroemia sp., damonella pygmaea (an derson, 1941), damonella ellipsoidea (wolburg, 1962), “bisulcocypris” dilatata anderson, 1971, and rhi nocypris jurassica (martin, 1940). marine genera are rare and represented by a few specimens of dicrorygma, asciocythere? and cytheropterina. the vertebrate fauna from the pointe de chassiron consists of chondrichthyans, osteichthyans and tetrapods. tetrapods have been reported in 14 beds from the purbeckian succession (beds b104 to b203a from bousquet, 1967). they include remains from a lissamphibian, turtles, a lepidosaurian, crocodilians, pterosaurs and dinosaurs (lapparent & oulmi, 1964; rieppel, 1980; billon-bruyat et al., 2001; bil lon -bruyat, 2003). a detailed list and a description of these tetrapods is given in billon-bruyat (2003). bed 148 (b148 from bousquet, 1967) was termed a bone-bed and is considered the horizon with the most diverse vertebrate fauna in the section. a preliminary study of chondrichthyans and osteichthyans from this bed was carried out by vullo (2001), who reported a number of families living in marine or margino-littoral environments. a recent isotopic geochemical study showed that semionotidae remains from bed b148 are of marine origin (billon-bruyat et al., 2005). tetrapod remains from the same bed include a lissamphibian (urodela incertae sedis), turtles (plesiochelyidae), crocodilians (teleosauridae, atoposauridae, goniopholididae, ber nissartiidae), pterosaurs (pterodactyloidea indet, pterosauria indet.) and dinosaurs (theropoda indet.). most of these taxa were identifi ed on the basis of microremains, mainly isolated teeth. only the plesiochelyids, teleosaurids, goniopholidids and a theropod are represented by larger remains. the stratigraphic distribution of these tetrapod families is consistent with a latest jurassic age. they were known from the jurassic and cretaceous with the exception of plesiochelyids, which disappeared in the tithonian, and teleosaurids, which are only represented in the cretaceous by a single questionable specimen (cornée & buffetaut, 1979; benton, 1993; bardet, 1995). a margino-littoral depositional environment is consistent with the composition of the tetrapod fauna. plesiochelyids and teleosaurids in particular are considered as co ast al marine reptiles (buffetaut, 1982; broin, 1994; bardet, 1995). in addition, billon-bruyat et al. (2005) reported that samples from these families in bed b148 indicate a marine isotopic signal. their remains were abundant and include some connected bones. all the other tetrapod families were non-marine, either freshwater/terrestrial (lissamphibians), freshwater/brackish (goniopholidid, bernissartiid crocodilians), terrestrial (atoposaurid crocodilians, theropod dinosaurs) and aerial elements (pterosaurs). the occurrence of these continental families in the margino-littoral depositional environment clearly refl ects a freshwater infl ow. 3. systematic palaeontology division charophyta migula, 1897 class charophyceae smith, 1938 order charales lindley, 1836 family nitellaceae von leonhardi, 1864 emend. martín-closas & schudack, 1991 genus latochara mädler 1955 emend. feist in feist & cubaynes, 1984 latochara latitruncata (peck, 1937) mädler, 1955 (figs. 2.1–2.4) 1937 aclistochara latitruncata peck, n. sp. – peck, p. 89, pl. 14, fi gs 1–4 1955 latochara latitruncata (peck) nov. comb. – mädler, p. 271 1957 latochara latitruncata (peck) – peck, p. 32–33, pl. 5, fi gs. 7, 21–33 1957 latochara concinna peck, n. sp. – peck, p. 34, pl. 5, fi gs. 5–6, 8–9 1990 latochara latitruncata (peck 1937) mädler 1955 – schudack, p. 219, pl. 2, fi gs. 1–4 1993 latochara latitruncata (peck 1937) mädler 1955 – schudack, p. 56, pl. 4, fi gs. 1–4 material: about 200 gyrogonites from sample 148b. description: medium-sized gyrogonites, in shape sub spherical to ellipsoidal. length ranges 351–432 mm (average 404 mm), including the neck. width ranges 270–351 mm (average 312 mm). isopolarity index 123–136 (average isi 129). geologia croatica geologia croatica 61/2–3 180 spiral cells are fl at or slightly concave with carinated sutures. the number of convolutions visible in frontal view ranges from 10 to 13. apex generally pointed. apical neck generally short and pyramidal but in isolated specimens may be almost prismatic, similar to the neck of stellatochara. when approaching the neck, spiral cells become fi rst wider and then narrow suddenly up to the summit. in this area the spiral cells are strongly concave. a periapical depression is present in some specimens. the apical pore is small and hardly visible. base rounded or truncated. basal plate not observed, but probably multipartite, as in other species of the genus. discussion: the population studied belongs to mediumsized jurassic and lower cretaceous latochara species. these are l. latitruncata, l. collina peck, 1957, l. concinna peck, 1957, l. tenuicostata (peck, 1937) and l. maedleri schudack, 1996. other species are smaller, i.e. about 300 mm average length (l. mensinki schudack, 1990 and l. bellatula peck, 1957) or larger, i.e. more than 500 mm average length (l. sphaerica peck, 1957 and l. durand-delgai feist 1984) and will be not be considered for comparison. the population studied is similar in size and shape to l. latitruncata (peck, 1937) from the tithonian and kim meridgian of the morrison formation (usa), with the difference that this population is more ellipsoidal and has more numerous and thinner spiral cells. the specimen shown by peck (1957, pl. 5, fi g. 22) is very close to this population in its numb er of convolutions and general shape. apart from the morrison formation, this species was reported from the lower kimmeridgian of the saxony basin (nw germany), by schudack (1993) and from the tithonian of the dnieper-donets basin (ukraine) by shaďkin (1967). the german material shown by schudack (1990, 1993) differs from the population studied here in the stronger calcifi cation of spiral cells. the number of convolutions is somewhat smaller but overlaps with the range of the french population. latochara collina peck 1957 is very close to the previous species and peck (1957) suggested that they may be distinct only at the sub-species level. the only noticeable difference between the two species is the shape of the intercellular sutures which is wavy in l. collina. this may give a knotty aspect to spiral cells. this characteristic is not present in this material. schudack (1993) points to the larger width (sublat shape) and the truncated summit of gyrogonites to distinguish this species; however these characters are also present in latochara latitruncata, as clearly indicated in its species description. latochara concinna peck 1957 is considered in the original description as being very similar to l. latitruncata and schudack (1993) concludes that both species are synonymous, a point of view to which we adhere. latochara tenuicostata peck 1957 from the aptian of wyoming is somewhat smaller than the material here, but is similar in the number of convolutions. however, the apical pore of this species is large and rose-shaped, unlike the apical pores of other latochara. this pore is reminiscent of the apical pores of clavatoraceae. also the overall aspect of the gyrogonite, including its pointed base, is similar to internal casts of the fructifi cation of genus atopochara. peck (1957) noticed the presence of clavatoracean remains associated with latochara tenuicostata. in consequence, it appears that this species should not be ascribed to the genus latochara but rather to an internal cast of a clavatoracean oosporangium. latochara maedleri schudack, 1996 from the berriasi an of nw germany is distinct from other species in its extremely truncated apex, which results in a very wide gyrogonite. this form does not occur in the material described here. fi gu re 2: early tithonian charophytes from bed 148 at the pointe de chassiron. 1, 2: latochara latitruncata. lateral view of two gyrogonites showing globulosity and pointed apex. 3: lateral view of gyrogonite showing an elongated shape and an apical neck. 4: lateral view of a wellcalcifi ed gyrogonite showing a conical apex. 5: mesochara gr. voluta. lateral view of gyrogonite showing drop shape and prominent sutures. geologia croaticacarles martín-closas et al.: palaeobiogeography of the genus latochara (fossil charophyta) in the upper jurassic of southern europe... 181 family characeae (r. ex c. agardh, 1824) emend. martín-closas and schudack, 1991 genus mesochara grambast, 1962 mesochara gr. voluta (peck, 1937) emend. peck, 1957 nov. comb. grambast, 1965 (fig. 2.5) 1937 chara voluta peck, n. sp. – peck, p. 85–86, pl. 14, fi gs. 16–19 1957 praechara voluta (peck) – peck, p. 39, pl. 7, fi gs. 7, 22–27 1965 mesochara voluta (peck) nov. comb. – grambast, p. 581 material: six gyrogonites from sample 148b. description: the gyrogonite is small, 270–350 mm in high and 240–300 mm wide. isopolarity index ranges between 100 and 120. the gyrogonite is normally drop-shaped with a fl at apex and a pointed base. some specimens also show a pointed apex. the maximum width is above the middle point. in pro fi le, 7–8 convolutions are visible, separated by prominent ridges. in the equatorial zone, spiral cells are between 25–60 mm high. apex closed by simple junction of spiral cells. base shows a pentagonal pore with a maximum diameter of about 50 mm. basal plate not observed. discussion: the group voluta has a wide chronostratigra phic range, from the kimmeridgian to the barremian (schudack, 1993; martín-closas, 2000). 4. palaeobiogeography whilst latochara from the lower jurassic is known from south ern france, (feist and cubaynes, 1984), in the up per jurassic and lower cretaceous, the genus was exclusively known from the boreal domain, i.e. regions north of the tethyan sea. peck (1957) and schudack et al. (1998) reported the genus in the kimmeridgian and berriasian of the morrison formation (western united states), feist et al. (1995) in the upper tithonian–lower berriasian from the purbeck facies in england, schudack (1993) from the kimmeridgian, tithonian and berriasian in the north-western german basins, and shaďkin (1967), from the tithonian of the dnieper-donetz basin (fig. 3). however, the genus is completely un known in the tithonian–berriasian basins of central tethys, i.e. in the iberian peninsula, sardinian high, provence and northern africa, where charophyte associations were generally dominated by clavatoraceans during that period (schudack et al., 1998; martín-closas, 2003). in consequence, the latochara genus was considered by schudack (1996) as one of the most characteristic genera of the northern charophyte biogeographic province during the kimmeridgian–tithonian and berriasian. he hypothesized that a thermal barrier at 20°c of mean winter temperature would account for the biogeographic boundary (fig. 3). the occurrence of latochara tenuicostata at oléron island, southwestern france, during the late jurassic, allows us to shift the known biogeographic distribution of this genus 570 km southwards, to touch the northern margins of the mesogea, in central tethys. the new distribution suggests that the biogeography of the genus was not just controlled by temperature as proposed by schudack (1996). other factors, in addition to temperature, may have hindered the expansion of the genus into the central tethyan islands (iberian peninsula, sardinian high and morocco meseta). the next upper jurassic-lower cretaceous charophyte locality south of oléron island occurs in the lower berriasian lacustrine limestone of the aguilar de campoo fm, cantabrian chain, where charophyte assemblages are dominated by globator maillardii praecursor and clavator reidii (hernández et al., 1999). this formation is attributed to deposition in large, permanent, alkaline and freshwater lakes without any marine infl uence. also the other localities from iberia (schudack, 1993), the sardinian high (colin et al., 1985) and the morocco meseta (mojon, 2002) correspond to lacustrine limestone belonging to freshwater alkaline lakes, whilst localities dominated by latochara, such as the new occurrence described here, correspond to brackish or littoral marshes. in conclusion, palaeoecology also appears to play a signifi cant role in the distribution of latochara in addition to climate. it is known that late jurassic and early cretaceous charophyte assemblages dominated by porocharaceans, (the family to which latochara belongs), are cha racteristic of brackish environments (martín-closas & grambast-fessard, 1986; mojon, 1989). palaeoenvironmental factors, such as water alkalinity or salinity, may be an important factor in the palaeogeographic distribution of meso zoic charophytes. also, the conjoint or disjoint disposition of gametangia has to be taken into account when drawing the biogeography of fossil species. proctor (1980) showed that monoecious species of extant chara were cosmopolitan whilst dioecious ones were restricted to single land masses. this was found to be signifi cant in at least one early cretaceous species, atopochara trivolvis according to martín-closas & wang (2008). fi gu re 3: global distribution of tithonian latochara with its southernmost location on oléron island, beyond the winter isotherm of 20°c (modifi ed from schudack et al., 1998). legend: 1–5 localities in the morrison fm (united states), 1. montana, 2. south dakota, 3. central and eastern wyoming, 4. east-central utah, 5. colorado, 6. purbeck basin, s. england, 7. saxony basin, n. germany, 8. oléron island, charente basin, france. geologia croatica geologia croatica 61/2–3 182 5. conclusion bone bed 148 of the pointe de chassiron section on oléron island, (charente-maritime, france) contains a tithonian assemblage of latochara tenuicostata and mesochara gr. voluta that represents the southernmost occurrence of the genus latochara in the latest jurassic-earliest cretaceous of europe. this genus, which was considered by schudack et al. (1998) to be characteristic of a boreal charophyte region, occurs beyond the southern boundary (as set by these authors at the 20°c isotherm of winter temperature) of this boreal region. since all the latest jurassic to earliest cretaceous localities without latochara, occur south of oléron island and were deposited in freshwater alkaline lakes we suggest that palaeonvironmental factors as well as thermal boundaries were involved in the biogeographic distribution of the genus. acknowledgement this study is a contribution to the project cgl2005-00404 of the spanish ministry of science and technology. we acknowledge the facilities provided by the serveis científi cotècnics unit of the university of barcelona for studying the charophyt es using the sem. the english text was revised by mr. robin rycroft (servei d’assessorament lingüístic, universitat de barcelona). we also thank dr. p. hantzpergue (lyon) for providing fi gure 1 and m. dominique abit for allowing access to his collection and for his assistance during the sampling. the manuscript was greatly improved after peer-review by monique feist (cnrs, montpellier) and j.p. berger (univ. of fribourg). references agardh, c.a. (1824): systema algarum. – lundae literis berlingianis, lund, 312 p. anderson, f.w. (1941): ostracoda from the portland and purbeck beds at swindon. – p. geologists assoc., 41, 373–384. anderson, f.w. (1971): the sequence of ostracod faunas in the wealden and purbeck of the warlingham borehole. – in: worssam, b.c. & ivimey-cook, h.c.: the stratigraphy of the geological survey borehole at warlingham, surrey. bulletin of the geological survey of great-britain, 36, 122–138. bardet, n. (1995): evolution et extinction des reptiles marins au cours du mésozoïque. – paleovertebrata, 24, 177–283. benton, m. j. (1993): the fossil record 2. – chapman & hall, london, 845 p. billon-bruyat, j.-p. (2003): les écosystèmes margino-littoraux du jurassique terminal et du crétacé basal d’europe occidentale: biodiversité, biogéochimie et l’événement biotique jurassique/crétacé. – unpublished phd thesis, university of poitiers (france), 254 p. billon-bruyat, j.-p., buffetaut, e. & abit, d. (2001): new occurrence of pterosaur remains in the latest jurassic of western france. – strata, 1, 20–22. billon-bruyat, j.-p., lécuyer, c., martineau, f. & mazin, j.-m. (2005): oxygen isotope compositions of late jurassic vertebrate remains from lithographic limestones of western europe: implications for the ecology of fi sh, turtles and crocodilians. – palaeogeogr., palaeoclim., palaeoecol., 216, 359–375. bourgueil, b., moreau, p., dubreuilh, j. & vouvé, j. (1976): notice de la carte géologique de la france au 1/50 000 n°657, île d’oléron. – bureau des recherches géologiques et minières, paris, 23 p. bousquet, p. (1967): contribution à l’étude stratigraphique et micropaléontologique du jurassique et du crétacé de l’île d’oléron (charentes-maritime). – thèse de la faculté des sciences, université de paris, 180 p. broin, f. de (1994): données préliminaires sur les chéloniens du tithonien inférieur des calcaires lithographiques de canjuers (var, france). – geobios mém. spéc., 16, 167–175. buffetaut, e. (1982): radiation évolutive, paléoécologie et biogéographie des crocodiliens mésosuchiens. – mém. soc. géol. france, 142, 1–88. colin, j.p., feist, m., grambast-fessard, n., cherchi, a. & schroeder, r. (1985): charophytes and ostracods from the berriasian (purbeckian facies) of cala d’inferno (nurra region, nw sardinia). – boll. soc. paleontol. ital., 23, 345–354. cornée, j.-j. & buffetaut, e. (1979): découverte d’un téléosauridé (crocodylia mesosuchia) dans le valanginien supérieur du massif d’allauch (sud-est de la france). – c. r. acad. sci., paris, 288, 1151–1154. delfaud, j. & gottis, m. (1966): sur quelques fi gures de sédimentation dans le portlandien du lot et sur leur cadre paléogéographique en aquitaine septentrionale. – actes de la société linnéenne de bordeaux b7, 103, 3–9. donze, p. (1960): les formations du jurassique terminal de la partie nw de l’île d’oléron, charente maritime. – travaux du laboratoire de géologie de la faculté des sciences de lyon, num. spec., 5, 1–30. feist, m. & cubaynes, r. (1984): découverte de charophytes dans le lias du sud de la france. implications paléoécologiques et phylogénétiques. – c. r. acad. sci., paris, 299, ser. ii, 593–596. feist, m., lake, r.d. & wood, c. j. (1995): charophyte biostratigraphy of the purbeck and wealden of southern england. – palaeontology, 38, 407–442. grambast, l. (1962): classifi cation de l’embranchement des charophytes. – naturalia monspeliensia, série botanique, 14, 63–86. grambast, l. (1965): état des connaissances acquises sur les charophytes du crétacé inférieur. – mémoires du bureau des recherches géologiques et minières, 34, 577–582. hantzpergue, p. (1989): les ammonites kimméridgiennes du hautfond d’europe occidentale: biochronologie, systématique, évolution, paléobiogéographie. – cahiers de paléontologie, éditions du cnrs, 428 p. hantzpergue, p., boullier, a., colin, j.-p. & abit, d. (2004): nouveaux repères biostratigraphiques à terebratulidés (brachiopodes) dans le tithonien inférieur ouest-européen. – geobios, 37, 361–375. hantzpergue, p. & lafaurie, g. (1994): les calcaires lithographiques du tithonien quercynois: stratigraphie, paléogéographie et contexte biosédimentaire. – in: bernier, p. & gaillard, c. (eds.): les calcaires lithographiques: sédimentologie, paléontologie, taphonomie. geobios, ms, 16, 237–243. hernández, j.m., pujalte, v., robles, s. & martín-closas, c. (1999): división estratigráfi ca genética del grupo campoo (malm-cretácico inferior, so cuenca vascocantábrica). – revista de la sociedad geológica de espańa, 12, 277–296. jacquin, t., dardeau, g., durlet, c., graciansky, p.-c. de & hantzpergue, p. (1998): the north-sea cycle: an overview of 2nd-order transgressive/regressive facies cycles in western europe. – sepm spec. publi., 60, 445–466. geologia croaticacarles martín-closas et al.: palaeobiogeography of the genus latochara (fossil charophyta) in the upper jurassic of southern europe... 183 jones, t.r. (1885): on the ostracoda of the purbeck formation with notes on the wealden species. – quarterly journal of the geological society of london, 41, 311–353. lantz, j. (1958): étude des spores et pollens d’un échantillon purbeckien de l’île d’oléron. – rev. micropal., 1, 33–37. lapparent, a.f. de & oulmi, m. (1964): une empreinte de pas de dinosaurien dans le portlandien de chassiron (île d’oléron). – comptes rendus sommaires de la société géologique de france, 61, 232–233. leonhardi, h. von (1864): die bisher bekannten österreichischen armleuchter-gewächse besprochen von morphogenetischen standpunkte. – verhandlungen der naturforschende vereins zu brünn, 2, 122–224. lindley, j. (1836): a natural system of botany. 2nd edition. – longman, london, 526 p. lyell, c. (1855): manual of elementary geology. 5th edition.− little, brown and co., boston, 655 p. malz, h. (1958): die gattung macrodentina und einige andere ostracoden-arten aus dem oberen jura von nw-deustchland, england und frankreich. – abhandlungen der senckenbergischen naturforschenden gesellshaft, 497, 1–67. malz, h. (1966): rectocythere rugosa, eine neue ostracoden-art aus dem französischen portlandian. – senckenbergiana lethaea, 47, 405–409. mädler, k. (1955): zur taxinomie der tertiären charophyten. – geologisches jahrbuch, 70, 265–328. martin, g.p.r. (1940): ostracoden des norddeutschen purbeck und wealden. – senckenbergiana, 22, 275–402. martin, g.p.r. (1958): cetacella, eine neue ostracoden-gattung aus dem kimmeridge nordwestdeustchlands. – paläontologische zetschrift, 32, 190–196. martín-closas, c. (2000): els caròfi ts del juràssic superior i cretaci inferior de la península ibèrica [charophytes from the upper jurassic and lower cretaceous of the iberian peninsula – in catalan]. – arxius de les seccions de ciències, institut d’estudis catalans, 125, 1–304. martín-closas, c. (2003): the fossil record and evolution of freshwater plants. a review. – geologica acta, 1, 315–338. martín-closas, c. & grambast-fessard, n. (1986): les charo phytes du crétacé inférieur de la région du maestrat (chaîne ibérique, catalanides, espagne). – paléobiologie continentale, 15, 1– 66. martín-closas, c. & schudack, m.e. (1991): phylogenetic analysis and systematisation of post-palaeozoic charophytes. – revue de la société botanique de france, 138, actualités botaniques, 1, 53–71. martín-closas, c. & wang, q. (2008): historical biogeography of lineage atopochara trivolvis peck 1941 (cretaceous charophyta). – palaeogeography, palaeoclimatology, palaeoecology, 260/3, 435–451. migula, w. (1897): die characeen deutschlands, österreich und der schweiz [the characeans of germany, austria and switzerland – in german]. – in: rabenhorst, x. (ed.): kryptogamic flora, vol. 5. e. kummer, leipzig, 1–765. mojon, p.o. (1989): polymorphisme ecophenotypique et paléoécologique des porocharacées (charophytes) du crétacé basal (berriasien) du jura franco suisse. – rev. paléobiol., 2, 505–524. mojon, p.o. (2002): la lignée phylogénétique des hemiglobator nov. gen – globator (clavatoracées, charophytes) du jurassique terminal – crétacé inférieur de l’europe et de l’afrique nord-occidentale. – archives des sciences genève, 55, 33–45. palamarev, e. (1971): fossile charophyten aus der unterkreide nordbulgariens. – mitteilungen des botanischen instituts, 21, 145–159. peck, r.e. (1937): morrison charophyta from wyoming. – j. paleontol., 11, 83–90. peck, r.e. (1957): north american charophyta. – geol. surv. prof. paper, 294 a, 44 p. pinto, i. & sanguinetti, y. (1962): a complete revision of the genera bisulcocypris and theriosynoecum (ostracoda) with the world geographical and stratigraphical distribution. – escola de geologia de porto alegre, publ. esp., 4, 1–165. proctor, v.w. (1980): historical biogeography of chara (charophyta) an appraisal of the braun-wood classifi cation plus a falsifi able alternative for future consideration. – j. phycol., 16, 218–233. rieppel, o. (1980): the skull of the upper jurassic cryptodire turtle thalassemys, with a reconsideration of the chelonian braincase. – palaeontographica abt. a, 171, 105–140. roemer, f.a. (1839): die versteinerungen des norddeutschen oolithengebirges. – hahn, hannover. rusciadelli, g. (1999): stratigraphie séquentielle et analyse de l‘espace disponible du jurassique supérieur et du crétacé inférieur du bassin de paris. – atti ticinensi di scienze della terra, serie speciale 8, 3–83. schnyder, j. (2003): le passage jurassique/crétacé: évènements instantanés, variations climatiques enregistrées dans les faciès purbéckiens français (boulonnais, charentes) et anglais (dorset). comparaison avec le domaine téthysien. – thèse de 3‘me cycle, universités de lille 1 et paris 6, 389 p. schudack, m. (1990): bestandsaufnahme und lokalzonierung der charophyten aus dem oberjura und unterkreide des nordwestdeutschen beckens. – berliner geowissentschaftliche abhandlungen (a), 124, 209–245. schudack, m.e. (1993): die charophyten im oberjura und unterkreide westeuropas. mit einer phylogenetischer analyse der gesamtgruppe. – berliner geowissenschaftliche abhandlungen (a), 8, 209 p. schudack, m.e. (1996): ostracode and charophyte biogeography in the continental upper jurassic of europe and north america as infl uenced by plate tectonics and paleoclimate. – in: m. morales (ed.): the continental jurassic. museum of northern arizona bulletin, 60, 333–341. schudack, m.e., turner, c.e. & peterson, f. (1998): biostratigraphy, paleoecology and biogeography of charophytes and ostracodes from the upper jurassic morrison formation, western interior, usa. – modern geology, 22, 379–414. shaďkin, i.m. (1967): fossil charophyta of upper jurassic deposits of the dnieper-donetz depression. – in: fossil algae of the uss. izdat nauk sssr, 43–47 [in russian]. sirna, g. (1968): the lower cretaceous charophyta and the paleogeography of mediterranean basin. – atti accademia nazionali lincei (rendiconti della classe di scienza fi siche, matematiche e naturali), serie 8, 44, 566–573. smith, g.m. (1938): botany. vol. i, algae and fungi. charophyceae. – mcgraw hill, new york, 127 p. steghaus, h. (1953): über die möglichkeit einer gliederung des weiss-jura von dalum. – berliner naturforschung gesellschaft, 42, 39–46. thierry, j. (2000): early tithonian (141–139 ma). – in: crasquin, s. (ed.): atlas peri-tethys, palaeogeographical maps-explanatory notes. ccgm/cgmw, paris, 99–110. geologia croatica geologia croatica 61/2–3 184 vullo, r. (2001): étude d’un niveau de type „bone-bed“ dans le tithonien (faciès purbeckien) de chassiron (île d’oléron, charentemaritime, france. – mémoire de maîtrise, université de poitiers (france), 20 p. wienholz, e. (1968): ostracodenfaunen der jura/kreide-grenzschicht en im norden der deutschen demokratischen republik. – berichte der deutschen gessellschaft für geologische wissenschaften, a, 13, 233–238. wolburg, j. (1962): die leitenden ostracoden des nordwestdeutschen wealden. – in: simon, w. & bartenstein, h.l. (eds): leitfossilien der mikropaläontologie. gebrüder borntraeger, berlin, 204–224. manuscript received december 20, 2007 revised manuscript accepted may 19, 2008 1. introduction in the scope of the groundwater quality monitoring programme near the remedied part of the “jakuπevec” waste depository (fig. 1), the three deeper structuralpiezometric wells were drilled, all of the similar depth, between 100.20 and 101 m. the wells were cored all the way, which means that a total of 301.70 m of core was available for field determination, whereby 92 samples were taken for various laboratory investigations. upon the correlation of the core determination with the well-logs, 82 samples were chosen in such a manner that all the stratigraphic and lithological units are covered by an equal density of samples and most were adequately represented (fig. 2). lithologic composition and stratigraphy of quaternary sediments in the area of the “jakuπevec” waste depository (zagreb, northern croatia) josipa veli∆ , bruno safti∆ and tomislav malvi∆ synthesis of all the data obtained from geologicgeophysical exploration resulted in certain ideas regarding the subsurface-geological relations of the “jakuπevec” waste depository area being formed. a detailed lithological determination was performed which helped to delimit the three chronostratigraphic units in the rank of series together with some smaller units. the large waste depository “jakuπevec” contains a mixture of communal and technological waste, and is presently partly arranged and organised. it is situated at prudinec locality between the villages of jakuπevec and miëevec in the south-eastern outskirts of zagreb (fig. 1). the waste depository lies parallel to the sava river on its southern bank, it is 1,500 m long and 400 m wide, covering an area of 600,000 m2. this position is totally unfavourable in many ways. apart from being located in the vicinity of the town, some 6.5 km from the centre, the waste-depository also lies in the groundwater geol. croat. 52/2 119 130 7 figs. zagreb 1999 key words: pleistocene, holocene, freshwater sediments, erosional unconformity, palaeoclimate, “jakuπevec” waste depository, zagreb, croatia. kljuëne rijeëi: pleistocen, holocen, slatkovodne taloæine, erozijska diskordancija, klima tijekom kvartara, smetliπte “jakuπevec”, zagreb, hrvatska. faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, hr-10000 zagreb, croatia. abstract in the area covered by the “jakuπevec” waste depository, to a depth of 101 m, six lithological units were determined based on fieldwork and laboratory geologic-geophysical investigations. it was discovered that the silty-clayey units (units 1, 3 and 5) are covered by sandy-gravely (units 2 and 4) and gravely ones (unit 6), respectively. these units constitute the sediments of the middle and upper pleistocene and holocene and are separated by erosional unconformities. the pleistocene gravels are predominantly of quartz-quartzite composition, while the holocene ones are composed of carbonate cobbles and pebbles. in contrast, the sands exhibit a fairly uniform mineral composition throughout the column. the pleistocene silt and clay are mostly composed of muscovite-illite and quartz with lesser amounts of chlorite, kaolinite and smectite. there is a difference in composition of this fraction in unit 6, where the quartz, calcite and dolomite particles prevail and smectite and illite/smectite are absent. unit 3 is characterised by the goethite content. the pleistocene layers were formed in a lacustrine-marshy environment while the holocene sediments are fluviatile. this sedimentary sequence is interrupted by occasional terrestrial phases, or drying-up periods, dependent on the palaeoclimate conditions, particularly the interchange of cold and dry glacials with the warmer and more humid interglacial stages. saæetak u podruëju smetliπta “jakuπevec” do dubine od 101 metra na osnovi terenskih i laboratorijskih geoloπko-geofiziëkih istraæivanja razluëeno je πest litoloπkih jedinica, pri ëemu se izmjenjuju praπinasto-glinovite (1., 3. i 5. jedinica) s pjeskovito-πljunkovitima (2. i 4. jedinica), odnosno πljunkovitima (6. jedinica). one izgrauju naslage srednjega i gornjega pleistocena te holocena, a odvojene su povrπinam a erozijskih diskordancija. pleistocenski πljunci preteæno su kvarckvarcitnog, a holocenski vapnenaëkog sastava, dok je mineralni sastav pijesaka kroz cijeli stup dosta ujednaëen. pleistocenski prah i glina u glavnini sadræe muskovit-ilit i kvarc uz stanovite koliëine klorita, kaolinita i smektita. za razliku od toga, u πestoj jedinici prevladavaju kvarc, kalcit i dolomit, a smektita i ilit/smektita uopêe nema. znakovita je prisutnost getita u treêoj jedinici. pleistocenske taloæine nastale su u jezersko-moëvarnom, a holocenske u rijeënom okoliπu, s povremenim kopnenim fazama ili isuπivanjima ovisno o paleoklimatskim okolnostima, tj. izmjeni hladnih i suhih glacijala s toplijim i vlaænim interglacijalima. 120 geologia croatica 52/2 protection zone of both the existing and planned-to-bebuilt well fields (mayer & markovac, 1992). therefore, remediation of the waste-depository site was highlighted as the best solution in order to prevent its negative influence on environment, especially on groundwater quality. the quaternary sediments surrounding zagreb were firstly described in the beginning of the century (gorjanovi∆-kramberger, 1908). more recent papers can be grouped into hydrogeological ones (mileti∆ & bor»i∆, 1967; novinska et al., 1967; bor»i∆ et al., 1968; »akarun et al., 1987; mayer & markovac, 1992) and a geological group (crnkovi∆ & bu©i∆, 1970; ©imuni∆ & basch, 1975; hernitz et al., 1981; ©imuni∆ et al., 1988). since 1991, there has been a partial modification in approach to these kind of studies. based on the synthesis of all the available geologic-geophysical data and application of subsurface-geological methods, a successful reconstruction of the composition and structure of pleistocene and holocene sediments was completed to a depth of approximately 100 m. adequate chronostratigraphic subdivision was obtained with an improved understanding of the influence of drastic climate changes and quaternary palaeotectonism. the process started with exploration near samobor in the west (veli∆ & safti∆, 1991) and gradually encompassed the zagreb area (veli∆ & durn, 1993; veli∆ et al., 1995). the most recently explored area is a section of the south-eastern outskirts of zagreb (veli∆ & safti∆, 1996). 2. lithological composition of the sediments detailed lithological description, performed simultaneously with core determination undertaken in phases parallel to the advance of drilling, was later substantiated with granulometric measurements. apart from the sedimentary composition, the colour, mottling, macrofossil content, and presence of concretions and rhizocretions were noted. such complete analyses facilitated comparisons between the jm-7, jm-13 and jm-19 wells and correlation with previously explored localities (veli∆ & safti∆, 1991; veli∆ & durn, 1993; veli∆ et al., 1995; veli∆ & safti∆, 1996). down to the depth of 100 m the sediments are composed of loose or weakly cemented clastics gravels, sands, silts and clays in variable proportions. the shallowest part (upper 50 m) is dominated by gravels. they are underlain by a thin layer of silty clay overlying the following drilled sequence: gravels and sands; thin silty-clayey sediments; then more sand and finally silts and clays forming the lowermost 10 metres. obviously, fig. 1 location map. the 6 lithologic levels can be defined. based on field determinations and results of various laboratory investigations, each of these units is described in detail below. 2.1. lithologic unit 1 the oldest lithohorizon lies deeper than 90 m (jm13 well, fig. 2). in jm-19 well it was entered at a depth of 92.90 m, and in jm-7 well at 93.50 m (both in fig. 7). due to the fact that all three wells were stopped before encountering the basal margin of this unit, its thickness can only be estimated, but it is surely more than 10 metres. granulometric measurements confirmed that this is the silty-clayey sediment that contains a certain amount of sand. the generalised composition is: 40-60 % silt, <20 % of clay with occasionally 20-30 % of sand. the colour varies from shades of grey and dark-grey, to bluish-grey and greenish-grey. a 121veliê, saftiê & malviê: lithologic composition and stratigraphy of quaternary sediments... fig. 2 lithologic column of jm-13 well. 122 geologia croatica 52/2 dark-grey coloration predominates, for instance, the complete interval of this unit in the jm-13 well is solely grey (fig. 2). the x-ray diffraction analyses (fig. 3) gave the following composition of silts and clays. the most abundant are particles of muscovite-illite and calcite as well as quartz, all in the range of 28 -30 %. dolomite comprises a significant 10 -15 % while other minerals contribute 4 -5 % chlorite, kaolinite and smectite. the light mineral fraction of sand is composed of 65 % of quartz, 20 % of rock fragments, 12 % of feldspar and 3 % of muscovite. the heavy mineral fraction (figs. 4 and 5) is dominated by transparent minerals (64 % in total) and is composed of garnets (41 %), epidotezoisite (21 %), amphibole and tourmaline (12 % each), together with disthene, staurolite and apatite (each approximately 3 %). these fine-grained deposits contain weathered white concretions, sporadic pebbles of lithothamnium limestone and flint, weathered and crumbly mollusc shells, gastropod operculums and carbonised plant remnants. an ostracod fauna was also determined, characterised by a uniform composition and quite a large number of specimens, indicating a lacustrine depositional environment and middle pleistocene age. the topmost 5 m of this unit is laminated. lamina-sets consist of a sequence of silty clays, clayey silt and fine-grained sand (< 1 mm thick laminae) thus making an alternation of dark-grey and light-grey laminae. each pair of lamina can be interpreted as a varve, whereby laminae of fine-grained sand were deposited in warmer periods, and siltyclayey ones in colder periods. these laminae depict lacustrine sedimentation, in other words, the transport of fine-grained material by watercourses flowing on the surrounding flood-plain. once brought into the lake, the fine-grained material spread in suspension and was deposited very slowly. 2.2. lithologic unit 2 the previously described silty-clayey unit is covered by another lithohorizon with a relatively abrupt contact between the two units. in the aforementioned three wells, this unit appears at different depth intervals: in jm-7 well it lies between 78.90 and 93.50 m (fig. 7), in jm-13 it is between 80.40 and 90 m (figs. 2 and 7) and in jm-19 in 80.30-92.90 m interval (fig. 7). in this way, the sandy unit 2 has a drilled thickness in the range of 9.60-14.60 metres, with a maximum in the jm-7 well and minimal thickness in jm-13. with a ratio of 30-90 %, sand is the dominant granulometric fraction of this sediment. the maximal amount of sand was drilled in the jm-7 well, in the deepest 2.5 m of this unit. the most common sand ratios are in the range of 50-60 %. other grain-sizes are also present. gravels occur in the range of 15-58 %, but mostly under 20 %. there is an increased amount of gravel in the 82.40-88.10 m interval of the jm-7 well. the maximal portion of silt is 25 % and clay was determined in the 5-10 % range. unit 2 was described in the field as a mostly grey or ash-grey uncemented sediment. it was also noted that sand contains sporadic pebbles and fragments, 3-4 mm in diameter, of both grey and white quartz, black quartzite, dark-red sandstones, green diabase and orange slate. occasionally, these pebbles are covered by a limonite coating having the colour of rust. in the jm-13 and jm-19 wells, the deepest 3-4 m are composed of fine-grained gravel and coarse sand. this interval is fig. 3 mineral composition histogram of core samples from wells jm-7 and jm-13 determined by x-ray powder diffraction. 123veliê, saftiê & malviê: lithologic composition and stratigraphy of quaternary sediments... covered by medium-grained sand, while the top of the unit is made of fine-grained sand with small amounts of silt and clay. such a clastic sequence, described on the basis of the field grain-size estimations, is substantiated by laboratory measurements and in part depicts the normally graded bed. in comparison to the older unit 1, sands of this unit contain a 10% higher ratio of quartz (70-75 %), significantly more muscovite (up to 9 %), somewhat smaller amount of feldspar (9 -11 %), while the presence of rock fragments varies (14-21 %). the mineral composition of the transparent heavy mineral fraction remained the same prevailing garnets followed by epidotezoisite, amphibole and tourmaline (figs. 4 and 5). the cobbles, pebbles and fragments of the gravel fraction are mostly composed of quartz and quartzite ( 5 6 .86 3 .3 %), then of dark-grey and black sandstones and siltites probably of palaeozoic age, and of darkred triassic and/or cretaceous sandstones and siltites ( 2 2 .6-2 3 .1 %). other rock fragments are the crystalline fig. 4 heavy fraction mineral composition of sand samples from well jm-13. fig. 5 transparent heavy minerals composition of sand samples from well jm-13. 124 geologia croatica 52/2 schists (0.98 .5 %), extrusives (1.4 -6 .3 %), limestones ( 2 .75 .4 %), chert (0.7-3 .6 %) and the dolomite (under 3.5%). in the jm-7 well, the clastic fraction with diameters larger than 4 mm is poorly sorted. it contains a quantity of well-rounded to subrounded and abraded grains measuring between 4 -10 mm, with solitary cobbles and angular fragments that reach up to 20 mm in diameter. the chert, extrusives and quartz/quartzite particles are well rounded and abraded. contrary to the situation in jm-17, in the jm-19 well the fraction above 4 mm is well sorted. due to the high level of roundness and comparatively small dimensions, most of the siliciclastic particles are interpreted to have gone through a number of cycles of reworking and redeposition. these grains must have originated from older clastic sediments, probably from the palaeozoic, triassic and cretaceous sandstones and siltites. 2.3. lithologic unit 3 the third unit is a bed of clayey silt and/or silty clay. in the jm-17 well it was drilled in the 77.10-78.90 m interval, so it is only 1.80 m thick (fig. 7). in the jm13 well this unit is 2 metres thick and comprises the 7 8 . 40 -80.40 m interval (figs. 2 and 7), while in the jm-19 it has a thickness of only 0.9 m and lies between 79.40 and 80.30 m (fig. 7). these clays and silt contain sporadic granules and small fragments (measuring a few millimetres) of quartz and quartzite. the unit is characterised by a mottled rusty-brown to brownishorange and gray coloration. apart from the irregular coloration, coloured lamina-sets were observed with characteristic change of the same range of tones. based on the granulometric analyses of cores taken from the jm-7 and jm-13 wells, the grain-size distribution of this sediment is such that clay particles prevail (48 50 %) but with an almost equal amount of silt (44 48 %). remaning particles have a size of fine-grained sand (fig. 2). there is a slight difference in composition of sediment drilled in the jm-19 well, where unit 3 is found to be composed of 22 % clay and 32 % silt with predominant sand (43 %) and some gravel (3 %). based on the cores taken from the jm-7 and jm-13 wells, the mineral composition of the silts was analysed (fig. 3). the dominant mineral constituents are muscovite-illite and quartz (30 40 %). the sample taken from the 77.2077.35 m interval of the jm-7 well gave 15 % of calcite, while in the same unit, this mineral has not been determined in well jm-13. an additional common characteristic of the unit 3 mineral composition is a significant amount of smectite and illite-smectite (1019 %). due to the adsorbing capabilities of smectite, even smaller proportions in the underlying rocks are of importance for the remediation process of the “jakuπevec” waste depository, because of the implications for the preservation of the groundwater quality. there is another important fact that has to be pointed out, too. this is the presence of goethite (up to 10 % in jm-7, and 6 % in jm-13). the dolomite has not been identified, not even in very small quantities. the presence of goethite in the unit 3 is in concordance with the characteristic brown colour of this sediment. it is interpreted as being formed after the lake/ marsh infilling, when a certain break in aquatic sedimentation occurred and a short-lasting terrestrial phase commenced with characteristic oxidation processes. 2.4. lithologic unit 4 in comparison to the previously described units, this one has the greatest thickness. in the jm-7 well it was drilled in the 52.70-77.10 m interval (fig. 7), in jm-13 between the 56.80 and 78.40 m (figs. 2 and 7) and in jm-19 in the depth interval 51.70-79.40 m (fig. 7), so the drilled thickness of this unit in the three wells thus is 24.40, 21.60 and 27.70 m. based on the granulometric composition, unit 4 is composed of several layers apart from the prevailing sands, there are sandstones, gravels and conglomerates. there are also a variety of colours grey, yellowish-grey, greyish-brown, brownish-grey and rusty-brown sediments were found. the sands and fine-grained gravels sporadically contain quartz and quartzite pebbles larger than 1 cm. the weakly cemented sandy conglomerate layers are 20 100 cm thick and are marked with the mottled cement grey, violet and rusty-brown. they contain a large portion of silty-clayey matrix. comparison of the granulometric composition did not result in the reliable correlation of this unit in all three wells, because the ratios of some fractions significantly vary with depth. the jm-7 well has the following column domination of sand (58 %) in the lowest 3.5 m, covered by 11 m of mostly sand and gravel (2840 % each) with the addition of silt and clay-size particles (less than 30 % together), and with the upper 9 metres of a prevailing sandy fraction (54 -68 %) and addition of 20 % of silt. the composition of unit 4 in jm-13 well is dominated by gravels which contribute around 50 % or more in most of this unit’s interval. there are only two smaller intervals that are the exception 67.0068.50 m mostly of sand (77 %) with remains of gravel and silt, and 59.40-61.90 m with nearly half sand (48 %) and rest of silt (fig. 2). it is only in the jm-19 well that unit 4 shows a certain degree of granulometric regularity. namely, there is an upwards-fining sequence with a gradual increase in the sand and silt content and a parallel reduction of gravel-size grains. the lower 9.5 m is dominated by 62-72 % of gravel, while the upper 16 m (or less) are characterised by a reduction in the gravel content from 18 % to 9 % followed by the increase in sand ratio from 20 % to 57 -65 % and silt ratio from 9 % over 18 % to 28 %. there is a potential for interpretation of this data in terms of depositional environment, especially of dynamic sand influx from a number of transport direc125veliê, saftiê & malviê: lithologic composition and stratigraphy of quaternary sediments... tions. however, in order to reach a more decisive and more substantiated conclusion, a larger number of analyses are needed from several wells. the quality of the analyses is also critical they have to be performed very carefully, taking measures to prevent the finer fractions from being washed out from the core. the laboratory analyses of 7 gravel samples showed the pebble-size contents in the 15.6 -4 1 .3 % range with 5 8 .7-84.4 wt. % of clayey-silty sand sediment. almost all the fractions above 4 mm are well sorted. their composition is markedly dominated by sub-rounded pebbles and fragments of quartz/quartzite measuring between 4-8 mm. there is also a comparatively high content of dark-grey and dark-red sandstones, probably of palaeozoic, triassic and/or cretaceous age, with some fragments of siltites and pelites. each of these rock components contributes within a characteristic range quartz and/or quartzites 53.4 6 8 .5 %, sandstones and conglomerates 12.2-29.1 %, limestones 3.21 3 .4 %, extrusive rocks 1.2 9 .3 %, crystalline schists 1 .8 6 .2 %, dolomite 0.8 5 .6 % and chert 0.8 3 .6 % (fig. 6). the sand mineral composition is generally comparable with that determined in the older units. light mineral fraction is composed mostly of quartz (58 -75 % ) , rock fragments (17-30 %), feldspars (4-13 %) and muscovite (1-8 %). garnet remained dominant in the transparent heavy mineral fraction, followed by epidotezoisite and tourmaline. pyroxene and rutile were for the first time determined as the fourth most frequent minerals. 2.5. lithologic unit 5 the previously described sandy-gravely unit is covered by clays and silts of unit 5. the pronounced lateral change of thickness is the marked characteristic of this layer. in the jm-7 well unit 5 lies in the 51.0052.70 m interval and is 1.7 m thick (fig. 7). in the jm-13 well it is between the 51.40 and 56.80 m (5.4 m thick, figs. 2 and 7). in the jm-19 well, the depth-interval of unit 5 is 4 8 . 00-51.70 m, where it is of medium thickness 3.70 m (fig. 7). these fine-grained clastics are, also like the older ones, coloured in shades of gray, bluish-grey, brown and rusty-brown, with an occasional mottled appearance. especially important is the topmost 20 cm of this unit in the jm-13 well, which has a very distinctive brown colour, resulting from palaeogeographic location and being due to soil forming processes during phases of subaerial exposure (veli∆ & durn, 1993). the clays of unit 5 contain thin, <20 cm thick layers of finegrained sands with some gravels. these layers are in brown tones and contain fossil mollusc shells, which are crumbly and impossible to separate from the sediment, so they could not be determined. in the jm-7 well, this was noted in the 51.50-52.30 m interval that contains 58 % of sand. in the jm-19 well, such a layer lies between 49.20 and 49.60 m having 20 % of sand and 57 % of gravel. apart from the aforementioned, the granulometric composition of this unit is 54 -67 % of silt and 23-42 % of clay. in addition to the fossil fauna, the clays contain carbonised plant remnants and angular quartz and quartzite fragments up to 5 mm in diameter. the mineral composition of silts and clays in unit 5 is dominated by muscovite-illite (30-35 %) and quartz ( 18 30 %). there is again a difference in the calcite contents in the jm-7 well it was found to be around 18 %, and in jm-13 only 1 %. the same spatial relation was observed in the unit 1. in both of these two wells, unit 5 contains a significant amount of chlorite (10 13 %) which makes a marked difference from all the fig. 6 mineral-petrographic composition of gravel fraction from well jm-13. 126 geologia croatica 52/2 previously described units and from the overlying unit 6. also, the second appearance of 5-12% of dolomite is stressed because it is totally absent in the unit 3 (fig. 3). in the thin layer of fine-grained gravel, the fraction above 4 mm is dominated by well-rounded platy and ellipsoid carbonate pebbles (49.3 %) and fragments measuring between 6 and 30 mm. a secondary component includes subangular to subrounded, occasionally rounded pebbles and fragments of quartz/quartzite ( 2 7 .4 %). well rounded, mostly platy pebbles and fragments of sandstones and sandy conglomerates compose 1 0 .5 %, and angular to subangular grains of chert and extrusives form 4.2 %, the same proportion as the crystalline schists. from each of the three wells, one specimen of sand was taken from the unit 5. based on the mineral composition analyses, there are no significant differences from the composition of older lithohorizons. in the transparent heavy mineral fraction, together with garnet and epidote-zoisite as the prevailing components, the topmost part of the unit contains equal proportions of amphiboles, tourmaline and rutile 6 %. 2.6. lithologic unit 6 the youngest and shallowest unit is mainly composed of gravels and sands mixed in different proportions. the following intervals were determined: in the jm-7 well from the surface down to the depth of 51.00 m (fig. 7), in jm-13 to the depth of 51.40 m (figs. 2 and 7) and in the jm-19 to the 48.00 m (fig. 7). these sediments are characteristic for the domination of wellrounded limestone and dolomite pebbles and cobbles, as well as for their colour. contrary to the older deposits, these sediments are markedly light-coloured light-grey, occasionally pale-yellowish. the two general conclusions can be drawn based on the granulometric results (1) the gravel fraction is markedly dominant ( 55 80 %) and (2) the granulometric composition is more-less uniform throughout the interval, meaning that gravel dominates the whole unit. sand forms the secondary component (18-25 %) and the remainder is silt and clay. the average clay content is only 1-3 %. neither the field core determination, nor the laboratory analyses, enabled identification of any phenomena that would facilitate further, more detailed correlation within this unit. the gravels of this topmost unit were represented by eleven samples. they contained 41.8 8 5 .4 % of fraction above 4 mm, with a weight percentage of muddy sand sediment in the 14.6 5 8 .2 % range. the fraction larger than 4 mm was found to contain both well-sorted and poorly sorted pebbles and cobbles with a diameter range up to 70 mm. the contribution of different petrographic types is limestones 32.5 5 7 .7 %, quartzquartzites 6.8 2 7 .3 %, dolomites 3.4 2 3 .3 %, sandstones and/or conglomerates 8.7 -21 %, extrusives 1.78 .7 %, cherts 0.7 6 .8 % and crystalline schists 0.6 6 .3 % (fig. 6). it is notable that the well rounded, platy to ellipsoidal carbonate pebbles and cobbles are the primary component of unit 6. there are also significant contributions of the well rounded, mostly platy, pebbles and cobbles of sandstones and conglomerates (under 21 %), and of the sub-angular to sub-rounded, seldom rounded quartz and quartzite grains (less than 27.3 % ) that as a rule make the finest part of the gravel fraction. the light mineral fraction of sand is composed of up to 70 % quartz with lithoclasts (16-26 %), feldspars (714 %) and muscovite (1 -5 %). the transparent heavy mineral fraction in this unit remained dominated by garnet in a somewhat smaller percentage (47 %) and by epidote-zoisite (under 34 %). it is interesting that a number of minerals comprise the fourth place amphibole, pyroxene, tourmaline and rutile. the presence of pyroxene is significant in light of the results of raffaelli & muti∆ (1982), who found this mineral to be characteristic for the holocene sediments of the zagreb area. in relation to the older units, the difference in composition of clays and silts of the unit 6 was expected. the most frequent mineral components are quartz (3065 %) and calcite (25 -55 %), with an addition of dolomite (30 %) in the shallowest sample from the jm13 well (7.4 -7.5 m sample in fig. 3). the rest of the minerals were present in small proportions (1% to exceptionally 6 %). the absence of larger quantities of chlorite is significant (<2 %), while smectite and illitesmectite are totally absent (fig. 3). 2.7. comparison of the results of quantitative determination of mineralogical-petrographic composition based on the results of quantitative determination of the mineralogical-petrographic composition of the gravel fraction, down to the depth of 92.8 m, two mineralogical-petrographic assemblages can be discerned. due to their petrographic-sedimentary characteristics, they are interpreted as being formed by depositional cycles with the same or similar source areas. the predominantly carbonate assemblage is described by the samples taken shallower than 32.20 m in jm-7 well, 45.5 m in jm-13 well and 46.9 m in jm-19 well. these are the holocene sediments and the sava river deposits. all of the other gravel samples are from the older, predominantly siliciclastic (quartz-quartzite) assemblage. according to its petrographic-sedimentary characteristics, these sediments are made of detritus that resulted from erosion of the mesozoic and palaeozoic rocks where by grain dimensions, roundness of the quartz/quartzite clasts and the high content of the most resistant clasts, it was found that the grains have undergone multiple cycles of weathering (erosion), transport and deposition. this makes it likely that the detritus of this assemblage, although it is from primary crystalline rock, in the holocene sediments mostly originates from the erosion and redeposition of the mesozoic and palaeozoic conglomerates and sandstones. with respect 127veliê, saftiê & malviê: lithologic composition and stratigraphy of quaternary sediments... to the 6 determined units, this means that the units 2 and 4 (and most probably one gravely-sandy layer of the unit 5), pertain to the older siliciclastic assemblage, while the unit 6 has a composition of the younger, carbonate mineral assemblage. these facts are very important for stratigraphic analysis. analysis for characteristic transparent heavy mineral compositions in the chronostratigraphic units was only partly successful. garnet is the most abundant mineral in all of the samples, occurring in the 30-60 % range regardless of sample location. epidote and zoisite are next with ranges from 9 -34 %, and similar proportions were determined throughout the whole studied sedimentary sequence. it is only on the basis of the quantities of amphibole, tourmaline and rutile that certain changes are observed. in more detail, the older, pleistocene sediments often have tourmaline as the third major mineral component (6 -16 %) and sometimes rutile, also. this is especially true for units 1, 2 and 4. in the units 5 and 6 the third mineral component is amphibole (8-11 %) and the pyroxene is determined in just a few percent, enough to characterise the holocene sediments. based on the mineral composition and morphologic characteristics of particles, it is concluded that the detritus originates mostly from the metamorphic and older sedimentary rocks, very rarely from the acidic igneous rocks. this finding is in concordance with the petrologic-sedimentary characteristics of gravels. by comparison of all the values of xrd analysis of silts and clays, the following factors are found to be potentially important for discrimination between units 1-6: unit 1 is dominated by muscovite-illite, quartz and calcite with a smaller amount of dolomite and some chlorite and kaolinite; unit 3 is characterised by the absence of dolomite and a lot of goethite the highest content within the studied sediments; units 3 and 5 have a predominance of the muscoviteillite and quartz with a significant quantity of smectite and kaolinite; unit 6 is mainly composed of quartz, calcite and dolomite, while the smectite and illite/smectite are totally absent. 3. stratigraphic relationships it is possible to define the stratigraphic relationships in the “jakuπevec” waste-depository area to the depth of 100 m, namely for the sedimentary sequence that was explored in detail by the three wells jm-7, jm-13 and jm-19. it is regrettable that jm-19 was not drilled to the depth of 120-150 m as suggested, because the basement of the middle pleistocene sediments could have been reached, and this stratigraphic surface roughly corresponds to the regional well-log marker q’. having taken the results of the previous exploration of quaternary sediments in the lowlands of the zagreb area (around samobor and podsused, veli∆ & safti∆, 1991), in the area of preëko (veli∆ & durn, 1993) as well as in the area of the zagreb centre (veli∆ et al., 1995), and comparing them with the findings from “jakuπevec”, the sediments are interpreted to belong to the quaternary system, and the pleistocene and holocene series within. the pleistocene sediments are further divided into the middle and upper pleistocene. this subdivision is partly confirmed by the results of the palaeontological investigations on 30 samples that were all macerated. the common characteristic of these samples was that they were not fossiliferous only 1 of 9 samples taken from the jm-7 well had a microfauna content, 4 out of 12 from the jm-13 and 3 out of 9 from the jm-19 well contained fossils. the most frequently encountered microfossils were ostracods, remains of gastropod operculums and partly destroyed micromolluscs. among the ostracods, two species were determined scottia gagicae soka» and cytherissa lacustris (g.o.sars) together with the larval forms of the c a n d o n a genus. the majority of samples contained only a small number of fossil specimens. the opposite was the case for unit 1 clayey silts and silty clays where an exceptionally rich and well preserved fauna of ostracods was found. although located at different depth intervals (93.80 -94 m in jm-7, 92 92.2 m and 93.4-93.5 m in jm-13 and 93.893.95 m in jm-19), all of the samples pertain to the same layer. the determined ostracod fauna of uniform composition allows a middle pleistocene age to be assigned to these sediments (soka», 1978). while drilling, the middle pleistocene sediments were encountered at different depths in the three wells (in jm-7 at 77.1 m, in jm-13 at 78.4 m and in jm-19 at 79.4 m). the quoted depths are given according to the core determination in the field. the well-logs shown in figs. 2 and 7 show slightly different depths and there is a small discrepancy between the well-log curve and lithological intervals drawn after the core determination. the middle pleistocene sediments encompass units 1, 2 and 3, two of which have the clayey-silty lithologic composition and one of sand. unit 3 is significant, because it marks the final phase of lacustrine-marshy sedimentation in the middle pleistocene and was for a certain period of time exposed on the surface, which resulted in its brownish and rusty colour. due to the fact that the basement of this chronostratigraphic unit was not reached by any of the three wells, the total thickness is difficult to estimate, but it is surely more than 23 m. between the middle and upper pleistocene sediments there is an erosional unconformity. the upper pleistocene sediments encompass the lithological units 4 and 5. they were both deposited in the newly-formed sub-aqueous environment and contain roughly equal proportions of gravels and sands. there is also a marked difference in thickness (the biggest in jm-19 well is 128 geologia croatica 52/2 fig. 7 correlation cross-section. ., 1 ~........ i ] n . '), i ) ) ) jo . 'r~ ~. ') } ..... : i 1~r-+-+-+-+-+-4-4-~~. ~~~.~, ~~~~~~~-rr..~~,~~~.r~~~(~~~,~h~-,/~.~ ~. i ..:.. r-:-: to:::::';: t · ... h i:;:,r, . -_-~ ~ r~".,,· j l .iii ... hu i i ~ ,,, ,.,--. ---... i--' 1\ .. -.-______ ~ __ f---' -.. ~ i '1. ou) [hj!d3ci i ; \i 129veliê, saftiê & malviê: lithologic composition and stratigraphy of quaternary sediments... 31.4 m, over 27 m in jm-13, to the smallest value of 26.1 m in jm-7). the apical part of this chronostratigraphic unit is also composed of fine-grained clastics that were altered under atmospheric influence. the presence of goethite is significant in this sense, because this is the mineral that forms from iron minerals in the oxidation zone of the weathering crust. this is a clear evidence of a second terrestrial phase. subsequent to the climatic changes and tectonic processes that enabled the sava to start flowing in its present river bed, the youngest chronostratigraphic unit was deposited. these are the holocene carbonate gravels (lithological unit 6) that were transported by the river and its neighbouring smaller tributaries and then deposited when the water flow lost the necessary energy, thus forming the sava alluvium. these gravels have a thickness in the range of 48 m (in jm-19 well) to the 51.4 m (in jm-13). in the jm-7 well, the 51 m was drilled. this thickness is several times greater than the thickness of the sava carbonate deposits that was determined in the preëko area (veli∆ & durn, 1993) which depicts local changes of depositional environment most probably due to the tectonic movements. the exact explanation would become possible only after the additional study of both the “jakuπevec” locality and its broader surroundings. the relationship between the delimited chronostratigraphic units is illustrated by the schematic correlation cross-section (fig. 7). the most important features are deviations of the gamma-ray log (natural gamma radiation) in the intervals of erosional unconformities. this is because of the increased radioactivity of clays and silts in the topmost parts of the middle pleistocene and upper pleistocene sediments. 4. results and conclusion based on the synthesis of the fieldwork and laboratory results, the subsurface geological relationships under the reconstructed part of the “jakuπevec” waste depository are defined. the following findings are the most important. 1) the shallowest 100 m of sediments is composed of loose or poorly cemented gravels, sands, silts and clays mixed in variable proportions. 2) the six lithologic units are defined, depicting the changeable sequence of coarseand fine-grained clastics. the oldest, unit 1 is mainly composed of clayey silt and has a thickness of more than 10 m. unit 2 is 9.6-14.6 m thick and has a sandy-gravely composition. the third unit is again composed of clayey silt and is only 0.9 to 1.8 m thick. the overlying unit 4 is sandy-gravel and has a thickness in the 21.6-27.7 m range. unit 5 is clayey-silt and 1.75.4 m thick, while the topmost, youngest gravelysand unit has a thickness of 48-51.4 m. 3) the gravels of units 2, 4 and 5 are clearly differing from the ones in unit 6. the first gravels belong to the siliciclastic (quartz-quartzite) assemblage that was formed from detritus originating from the erosion of the palaeozoic and mesozoic rocks and has undergone multiple cycles of weathering, transport and deposition. the gravels of unit 6 are composed of carbonate (limestone) comprising the sava alluvium of holocene age. 4) the sand mineral composition is quite uniform. in all of the samples of the transparent heavy mineral fraction the most frequent minerals are the garnets, epidote and zoisite. in the older, pleistocene sediments (units 1, 2 and 4) tourmaline appears as the third most frequent mineral, while in the units 5 and 6 this place is taken by amphibole. this might represent one of the additional criteria for subdivision of quaternary sediments in the studied area. according to the described mineral composition and the morphologic characteristics of grains, the sand mostly originates from the metamorphic and older (palaeozoic mesozoic) sedimentary rocks. 5) the mineral composition of silts and clays is also comparatively uniform. there is a general predominance of muscovite/illite, quartz and calcite. certain differences were also observed that enable identification of the lithologic units. unit 1 is characterised by the regular presence of small amounts of chlorite and kaolinite. unit 3 has a significant proportion of goethite, smectite and kaolinite, and the last two minerals are also significantly present in unit 5, but without goethite. unit 6 is totally without smectite and illite/smectite. due to the adsorbing capabilities of smectite, even small proportions can be of importance for groundwater protection. that is why the hydrogeological significance of unit 3 is stressed, because it contains almost 20 % of smectite. 6) the studied sediments have a low fossil content. it is only in the samples taken from the 92-94 m interval that the uniform fauna of ostracods typical for the middle pleistocene was determined. 7) the sediments of units 1, 2 and 3 are of middle pleistocene age. above the erosional unconformity covering the unit 3, lie the upper pleistocene sediments of the units 4 and 5. there is another unconformity on the top of the pleistocene sediments which are overlain by unit 6 of holocene age. the sedimentary sequence is interpreted in terms of interchangeable deposition in the aquatic (lacustrine-marshy) and in alluvial environment with occasional emersion phases or dry-up periods which resulted from the climatic changes as described by veli∆ & durn (1993). 8) the achieved results indicate that only comprehensive and systematic geological investigation can yield the reconstruction of the subsurface relations 130 geologia croatica 52/2 and enable reliable correlation to be made. this correlation is most important from the hydrogeological point of view, especially in the groundwater protection aspect that was and still remains the aim of the “jakuπevec” waste depository remediation project. acknowledgements for permission to use the results of their laboratory analyses, the authors would like to express their gratitude to j. ti©ljar, m. sarkoti∆-©lat, d. slovenec and a. soka». the support and understanding of the research programme from the sides of g. hubeny, a. kerekovi∆ and m. matasovi∆ is also gratefully acknowledged. certain research activities were accomplished as a part of the scientific project no. 195018 “subsurface and geohazard explorations in croatia”, funded by the croatian ministry of science and technology. 5. references bor»i∆, d., capar, a., »akarun, i., kostovi∆, k., mileti∆, p. & tufek»i∆, d. (1968): prilog daljnjem poznavanju aluvijalnog vodonosnog horizonta na πirem podruëju zagreba.geol. vjesnik, 21, 303-309. crnkovi∆, b. & bu©i∆, m. (1970): mineraloπkopetrografski sastav nanosa rijeke save.zbornik radova rud.-geol.-naftnog fak. sveuë. zagreb u povodu 30 god. rada (1939-1969), 133-140. »akarun, i., mraz, v., babi∆, æ., muti∆, r., soka», a. & frani∆, d. (1987): geoloπke i hidrogeoloπke specifiënosti kvartarnog vodonosnog kompleksa prisavske ravnice na dionici granica sr slovenija-rugvica.geol. vjesnik, 40, 273-289. gorjanovi∆-kramberger, d. (1908): geologijska prijegledna karta kraljevine hrvatske-slavonije. tumaë geologijskoj karti zagreb (zona 22, col. xiii).nakl. kralj. zemalj. vlade, odjel za unutar. poslove, zagreb, 76 str. hernitz, z., kova»evi∆, s., veli∆, j., zeljko, b. & urli, m. (1981): primjer kompleksnih geoloπko-geofiziëkih istraæivanja kvartarnih naslaga u okolici prevlake.geol. vjesnik, 33, 11-34. mayer, d. & markovac, z. (1992): hidrogeologija podruëja smetliπta jakuπevac (zagreb).rudarsko-geoloπko-naftni zbornik, 4, 15-21, zagreb. mileti∆, p. & bor»i∆, d. (1967): prilog poznavanju podzemnih voda na podruëju zagreba.geol. vjesnik, 20, 285-291. novinska, n., mileti∆, p., bor»i∆, d. & tufek»i∆, d. (1967): prilog poznavanju aluvijalnog vodonosnog horizonta na uæem podruëju zagreba.geol. vjesnik, 20, 293-301. raffaelli, p. & muti∆, r. (1982): moguênost razdvajanja asocijacija teπkih minerala primjenom faktorske analize.x. jubilarni kongres geologa jugoslavije, zbornik radova, i, 495-508, budva. soka», a. (1978): pleistocene ostracode fauna of the pannonian basin in croatia.paleont. jugosl., 20, 151. ©imuni∆, al., novosel-©kori∆, s. & piljurovi∆, lj. (1988): litoloπka korelacija i kronostratigrafsko razgraniëavanje kvartarnih naslaga na lokalitetu prevlaka jugoistoëno od zagreba.geol. vjesnik, 41, 167-179. ©imuni∆, an. & basch, o. (1975): stratigrafija kvartarnih sedimenata zagrebaëkog posavlja.geol. vjesnik, 28, 153-164. veli∆, j. & durn, g. (1993): alternating lacustrinemarsh sedimentation and subaerial exposure phases during quaternary: preëko, zagreb, croatia.geol. croat., 46/1, 71-91. veli∆, j. & safti∆, b. (1991): subsurface spreading and facies characteristics of middle pleistocene deposits between zapreπiê and samobor.geol. vjesnik, 44, 69-82. veli∆, j. & safti∆, b. (1996): dubinskogeoloπki odnosi podruëja smetliπta “jakuπevec” ëimbenik sanacije.zbornik radova iv. meunarodnog simpozija “gospodarenje otpadom zagreb ‘96”, 197205, zagreb. veli∆, j., tadej, n., durn, g. & safti∆, b. (1995): genesis of quaternary deposits in the area of zagreb and surroundings of samobor.in: vlahovi∆, i., veli∆, i. & ©parica, m. (eds.): first croatian geological congress, opatija, abstracts, 97, zagreb. manuscript received july 16, 1999. revised manuscript accepted november 12, 1999. geol. croat. 49/2 251 257 6 figs. i 9 tabs. i zagreb 1996 review paper selection of exploration strategy slevo kolundzic key words: exploration, reserves replacement, highly explo red area, offshore, onshore, risk of expjo­ ration, turnover, production cost, public company. abstract the ex ploration of oil and gas depends on investmen ts and prospective area to be explored. exploration as a risky business, has \0 be fi nanced from company's resources, nol through loan. basical ­ ly, exploration provides oil and gas producers , who are financed through actual production. our prospective area is well explored and there is a diminished probability of discovering large deposits. production has a decreasing trend. thi s is why the strategy of exploration needs to be checked and redefined . especially as this coincides with poiitical and economic changes and with changes in owners hip. owners and/or their repre­ sen tatives arc ready to invest in exploration if the target is clear, the cost defined and there is a high probability of finding oil and/or gas. 1. introduction the transformation of the social and political sys­ tem, together with the consequences of war, have forced the oil industry of croatia to redefine its busi ­ ness strategy including that of cxploration. this strate­ gy shall remedy negative trend s and it has to be con­ vi/king enough [or the owner's representatives to make decisions on investment in exploration. forecast ing production and the state of reserves indicates the required volume o[ replacement reserves (over a given period). however, restrictive factors includc the access ibility of a quality exploration area under acceptable conditions and the availability of capi­ tal for cxploration. ina research & development, savska 41/10, hrloooo zagreb, croatia. proceedings kljucne rijeci: istrazivanje, obnova zaliha, visoka istrazenost, podmorje, ozemlje, istrazivacki ri zi k, ukupni prihod, trosak proizvodnje, javno poduzece. saietak progrnmiranje istrazivanja narte i plina prvenslveno ovisi 0 velicini sredstava za isitazivanje i raspolozivom i perspc klivnom istraznom prosloru. buduci je istrazivanje rizican posao, ono se ti pravilu finaneira iz vlastitih sredslava. to uvelike odreduje poliliku gospodarenja zalihama, odnosno proizvodnju. nas nacionalni prostor je visokoistrazen i mala je vjerojatnoca nalaza velikih zaliha. proizvodnjaje usia u irend pada. to su dovoljni razlozi da se vrednuje i nade i/ili potvrdi stra!egija istrazivanja. tim vise ~to to u nas koincidira s novim vlas nickim odnosima, a ovlastenici prosuduju strategiju koja, u odnosu na druga ulaganja, sadrzi nellobieajeno vetik rizik, dodu~e i profit, ali sve zastire jednako ncuobicajeno udaljen vrcmenski horizont desetak i vise godina. nasuprot tome , llspjch u!aganja u proizvodnju cipcla vidite u jednoj sezoni, u gradevinarstvu u jednoj god in i, a u vecini s lozenijih projeka!<l unlliar pet godina. 2. reserves and production as criteria for defining exploration strategy as production depend s both on reserves and the policy of exploitat ion, it therefore makes sense to con­ sider the influence of both parameters on defining the scope of exploration. on the basis of reserves, the mini­ mal objective in both the medium-term and particularly long-term periods, is to discover such rcserves and to prevent the decrease of existing ones over a certain peri­ od of time. this means that the replacement coefficient should be at least equal to 1 or greater than 1. production depends not only on the state of reservcs but also on the market. therefore, if production has an increasing trend, exploration would have to provide for reserves, while the economic base for fi nancing the exploration would grow as well. although, generally, it depends on the continuity of explorat ion successes, per­ centage of field dcplction and production costs. 252 north amd'ica south amcrica europe africa middlc east asia far east total sources (223) (223) (75) (259) (848) (443) ( 149) reserves by conventional methods proven reserves 45 74 30 59 268 96 30 potential reserves 67 45 is 1m 170 96 59 according to thc production criterion a lone (without possible market sales), in the present exp!oatation poli­ cy replacement reserves are required [or covering some 4 million toe/i or current annual production. 3. the scope of explora non and area quality as criteria for new strategy in terms of explorat ion [or oil and gas, the territory of croatia is a highly explored area. throughout some fifty years the oil and gas production expanded until the mid-eighties, which was largely a consequence of suc­ cessfu l exploration. from the discovery o[ the oojlo and kriz oil fields to that of the podravina gas fields, in each decade discoveries have been at ever increasing deplhs, and deposils (of oil and gas) have been found under progressively more complex condi tions of pres­ sure, temperature and huld composition. analyzing the results of exploration in tcxas and wyoming in ihe usa (ivanhoe, 1996), il has been noted thai on a sample of over 750 wells there is a sta­ tistical regularity of inverted proportionality of layer thickness and permeability as well as permeability and porosity, and a direct proportionality of depth and pro­ duction cost. to some extent this is also confirmed in croatia in the discoveries of the molve, kalinovac and stari oradac fields. deeper and deeper exploration objectives require more extensive investments, simulta­ neously with the stagnant low price of oil and gas . bcsides, as mentioned earlier, croatia represents a highly explored area, the probability of finding a large quantity reserves has to be inversely proportional to the explored level. this aspect has been dealt with in the literature, periodically and mainly statistically, with the intention of establishing the volume o[ remaining reserves, their price, etc. during 1987, after the prices dropped precipitously from 30 to 10 us$/bbl and then seemingly stabi lized at i tons of oil equivalent per year. additional reserves after the application ofeor proven reserves 74 81 15 30 251 192 23 potential reserves 37 23 15 67 59 59 37 geologia croalica 49(2 table i estimate of the volume or sources and possibilities of conversion into rese rves (in i o~ bbl). uss 18, the president of elf aquilaine stated that with a price of 20 us$/bbl it would be possib le to convcrt 82% of resources into provcn rcserves (ooj, 1987a), which al the time amounted to 2200 bill ion bbl and this would cover 85% of annual consumption [rom 1987. the current est imates of the time were those based on the regional distribution of resources and reserves, shown in table 1. according to the same source, with the price of 12 us$/bbl it was possible to discover and bring to pro­ duction only 58% of the potential world reserves i. e. resources, while with a price of up lo 30 us$/bbl, as much as 95%. in ogj report (ogj, 1987b), there were mentioned almost 1000 fields discovered in offshore areas of the world, but they were not put into production because or the high cost. most of the fields (293) were found in ihe area oj" far east, 264 in the region of africa, and even 263 in the area of europe. in south america 98 fields were discovered, but only 51 % in the offshore. approx­ imately one third of these fields were found at sca depths of up to 30 m 271 fields, and 554 fields were discovered at depths from 30 to 120 m; at depths from 120-300 m 118 fields, and over 300 m 24 fields. _ mi<\dieed,,\ _ e £'iron. f$u, as'". 0<;""""" : _ wke'1'1's~_ai.-..;".w .8 . , i ~ l i ~ " fig. 1 history of oil production growth and forecasts of the flirt her course. from ivanhoe, 1996 (i·lubber! curve added by ivanhoe is weighted average of global oit discovered 1915-1992). kolulldiic : sd(;ctioll of exploration strategy 253 year 1987 1988 1989 1990 1991 1992 1993 1994 1995' total number of ri gs in operation 1050 900 860 1000 850 in the united states of ailler ica year 1982 1983 number of deep wells drilled 1205 577 average depth (m) 5290 5175 a vcrage price per well (1,000 us$) 6636 6095 number of producers 600 301 1t mu st be stressed that through exploration , croatia can discover new reserves but at the present price of oi l the cost of new reserves has to be acceptable. accord­ ing to this, the general philosophy of life reserve con­ firms the justifiability of exp loration even in highly explored areas. iv anh oe (l99s), by updating the hubbert curve attem pt s to answer a number of complex questions and presents statistica lly based arguments for constructing the oil life curve (fig. i). according to these results the world reserves will reach thei r maximum at the end of th is century. world oil exploration, pai1icularly drilling, has been conside rably red uccd si nce 1986, until the present. prom table 2 it can be observed that , with the excep­ tion of 1990 when the number of rigs in operation was somewhat increased , until 1993 there were less rigs in operation than in 1987. the exploration forecast in the offshore area as well as the production es timate were given by kvinns ­ land (1993) on the basis or samples in 89 countries. a number of we ll s were analysed and not the number of ri gs, but only the wells in the world offshore areas. according ky1nns land (1993) , in the four ycars following the decrease of ac tivity in 1986/7, the number of drilled wells worldwide was increas ing (to over 1200/year during 1988-1 991), with a si multaneo us decrease of wells in both the americas (less than 900). in 1993 therc appcal·cd an incrcasing trcnd of drilled wells with an expected further increase in the followin g years, in all the regions. access ible papers on future world exploration refer to a few general conclusions, which can be useful in our business strat egy and especially in the strategy of exploration. 1. the forecasting of a increase in exploration and development in the context of oi l and gas pri ces encourage our own explorational complex; 2. regional forecasting of exploration and development suggests that no extensive operations in the mediter­ ranean are foreseen (this renders more difficult the 750 1984 614 5099 5817 288 table 2 number of drilling rigs in operation in lhe period 650 1000 1000 from 1987 to 1993 (after kvinnsland, 1993 and galovic, 1(96). * data for the fi rst 6 months. 1985 1986 566 391 5170 5198 table 3 deve lopments in the 5574 5394 usa at the beg inn ing of the eighties, until the drop of pri 284 174 ces (from kvinnsland, 1993). marketing of our services, that is, of our free equ ip­ ment and manpower; 3. with respect to our foreign exp loration , besides community of independent states and in particular russ ia, effort s should be focused on the western coast of africa, especially angola where we have already been involved . thc us data presented in table 3 ind icate the devel­ opments at the beginning of the eighties, until the drop of prices. 4. sources of exploration financing it is well known that the possibi lity of ex ploration financing depends on current production. the financing of oil and gas exploration, due to the risks involved, is sourced as a rule , from the proper equity of the compa­ ny or from the pooled assets of a partner. credit financ­ ing should not be used . the international accounting system appl ied in croatia since 1994 has brought about considerable changes in the method of exploration f inancing, and now requires that special care be taken over expenditure, in order to provide continuity in ex ploration (under the current or cven declining oil prices). positive di scovery and revival of production shall increase the turnover. tabl e 4 shows that between 1960-1981 naj'taplin surpassed, in oil product ion , the limit 01'0.8 mil. t per year in 1960 and in 1970 it sur­ passed 2 mil. t and in 1980 3 mil. t. natural gas produc­ tion started vith 100 mil. m 3 in 1964, 500 mil. m 3 in 1971 surpassing i bi!. m3 in 1981. the turnover and particularly income, due to the price policy and to con­ stant economic changes do not completely follow the increas ing product ion although th e turnover (and thc economic power of the company) do follow, to a cer­ tain degree , the curve of a pretty reg ula r production increase. in the eighties (table 5), increased investment into exploration resulted from a large share of the offshore year oi l gas tons of oi l (i) (1000 m') equivalent (toe) 1960 768,028 38,564 806,592 1961 1,125,034 55,472 1,080,506 1962 1,156,476 61,419 1,234,313 1963 1,151,005 77,837 1,228,842 1964 1,285,362 130,602 1,415,965 1965 1,415,921 15 1, 106 1,567,027 1966 1,545, 110 188,826 1,733,936 1967 1,702,005 232,359 1,934,364 1968 1,8 18,336 329,728 2,148,064 1969 1,931 ,641 408,624 2,340,265 1970 2,055 ,248 477,671 2,532,919 1971 2, 136,791 547,537 2,684,328 1972 2,326,456 569,162 2,895,608 1973 2,422,930 611,723 3,034,653 1974 2,470,197 573,796 3, 143,993 1975 2,669,751 751,310 3,421,061 1976 2,812,779 911,185 3,723,964 1977 2,828,717 1,009,052 3,837,779 1978 2,93 1,166 934,294 3,865,460 1979 2,971,006 805,668 3,776,674 1980 3,056,388 983,241 4,039,629 198 1 3,140777 1,168,926 4,309,703 1982 3,047,194 1,244,541 4,29 1,735 1983 2,860,466 1,195,127 4,056,595 1984 2,853 ,327 1,231,493 4,084,820 1985 3,020,189 1,463,594 4,483,783 1986 3,006,856 1,699,388 4,706,244 1987 2,946,648 1,973,458 4,922,126 1988 2,844,668 2, 122,910 4,967,578 1989 2,705,166 2,176,657 4,881,923 1990 2,496,794 1,982,287 4,479,081 1991 1,902,956 1,838,876 3,741,832 1992 1,742,852 1,820,397 3,563,249 tablc 4 product ion of oil, gas and conditional oil in naftaplin from 1960-92 (kolundzic, 1995). exploration as well as from the exploration and devel­ opment of deep gas wells in podravina. in such a way, the expenditure was increased from 1/2 of the tota l rev­ enue to more than 2/3 . the mosl rapid increase of materi al and energy costs (as well as of foreign services) can be observed as a consequence of addressing more costly forms of exploration: greater depths, offshore dri lli ng area and an increase in the number of production fields. explo­ ration and deve lopment expenditure was being increased at lower rates. besides, the material and ener­ gy costs were increased quite surely as a consequence of a great number of wells, particularly for oil. during a great reduction of oil and gas prices (as in 1986), there shall bc det ermined the limit of profitable production geologia cromiea 49/2 per well and those wells which by their production do not cover the production costs wil l be cxcluded from production. table 6 shows a trend of increasing share or costs in the total revenue. around 1980 that share was betwcen 39-40% whereupon it started to increase. such a progressive increase of costs after 1985 was conditioned by the decrease in oil pricc in 1986, but it also shows that the costs were not reduced. to estimate exploration financing from 1989, in view of the production potential (fig. 2) over a fifteen­ year period, the resource will decrease with no signifi ­ cant price increasc. such an estimated profile affects the cash flow. with respect to the basic products, oil and gas, these projections arc shown in figs. 3 and 4. ij', in pri nciple, we expect ever reducing financia l resources for oi l and gas exploration, then these should be focused on the elements of efficiency regarding both our own services and the quality of concessions as well as the efficiency of lhe operators' activi ties. the exploration of oil and gas of ina -na ftaplin shows a growth of the efficiency coefficient from j 945 to 1985. as shown in table 7. the growlh of d ri ll ing efficiency has an intrinsic value, due to the fact that the efficiency is being increased although the structures are cons istently deeper, drillin g cond itions increasing ly more difficult, and the explored level indicator is ever higher. however, the correlat ion between the number of exp loration metres and tons of new production is, or course, not linear and it considerably depends upon the explored level indicators of the area concerned. the productiv ity as a rate of efficiency, suggests a dec line. through the combin ed influence of a price drop and furt her growth (i nstead of reductio n) of the number of employees, the productivity has tended to decline since the beginni ng of the eighties , and in the second ha lf of the decade became dramatic. the time dispari ty of the infl ection poi nts fo r the base ac tivit ies of ina arises out of constant changes of external and interna l cond itions of business activities . a series of key indicators from 1970-1990 show a break of conti­ nui ty in the middle of the eighties. ii may be slaled that from 1970 to 1990 the produc­ tion of natural gas increased and the production of oil after 1986 has been in gradual decline. the tota l pro­ duct ion of oil and gas, as shown in tons of oil equiva­ lent is in constant growth; howeve r, due to a fas ter growth of the number of employees, the prod uct ion in toe per employee since 1970 has decli ned (table 8). in addilion, the natural production of oil equivalent increased from 1970-1980 by 37%, from 1980-1985 by 11 .4% and from 1985-1990 by 3.6%. the reserves of oil and associated gas have decreased, and the rcserves of natural gas have increased (table 8). the absence of adequate reactions in the eighties, (by 1986 at ihe latest), should be attributed to the estab­ lished econom ic and political system in croatia. the rat ionalization and reduction of the number of employkolundiic: selection of exploration strategy year materihi and energy 1970 100 1975 332 1980 1,485 1985 28,964 1989 552,409 yem' 1981 1982 1983 1984 1985 1986 1987 1988 1989 services of others loa 462 1,369 17,428 172,398 depreciation 100 559 6,544 30,088 176,991 share of costs in total revenue (%) 39.6 46.4 46.0 44.8 58.8 77.9 80.6 82.6 96.2 table 6 share of cosis in the lotal revenue (from kolundzic, 1995). ees as one aspect of cost reduction was not possible, and a number of protective mechanisms depended there­ upon (table 9). in the ten-year period between 1984-1994 a sample of oil companies from the united states shows a growth of crfectiveness, both through reduction of discovery costs of 250% (fig. 5) and through a high reserve replacement rate (fig. 6). however, for the overall improvement of efficiency in the field of oil and gas exploration and production, cost cutting measures combined with organizational adaptation (down-sizing) will not give result s unless thi s is undertaken in conjuction with a reasonable explorat ion levcl. what is a reasonable level? the data supporting exploration efficiency and requirements for rcp lace­ ment of reserves suggest thai an investment or 6 us$ per boe produced is necessary in order to halt the decrease in production. i~i!! ! !!!!!!! ra gas condensate i_ natural gas lui" ! ! ! , ! ! ii! iii i ~ ! i y • ., fig.2 estimate of the produc1ion profile (from kolundzic, 1995). investment main tel1hl1ce 100 395 202 6,068 85,227 [nvest. into explor. & development lao 524 4,113 49,111 274,123 255 table 5 review of a relative increase of certain financial indicators in ina-naftaplin (from kolundzic, 1995). naftaplin planned to invest 49 million us$ for exploration within croatia and abroad and 40.5 million uss for development in 1995. in the relation to the total production of oil and gas and the value obtained at actual prices the planned investments make 3.8 us$ per produced boe or 1.9 us$/bbl for o il and gas explo ­ ration. in compliance with some data, 2.4 uss/bbl was spent on exploration in 1994. the relevant world literature reiterates the necessity for investment into new reserves from 6 to 8 uss/bbj. the data of the well-known auditing house arthur andersen showed on a model of several jnternational companies that the investments amounted to 5.6 us$/bbl in the year 1994. however, investments should be increased in rela­ tion to the actual ones within the realm of possibility and cont inuity shou ld be provided. the quality of exp loration and efficiency should be assured, through the possibility of select ing an exploration objective. 12000 10000 t----t-r-.... 8000 ~ m 6000 § 4000 2000 ~ :;: m ~ ~ i'tt--r--r-....t--t-t--t--h-a ~ 8 m ~ 0 n year b i t-f3 total net cash flow o tax 25% ocapex n • is ~ 0 0 0 0 0 " 0 n n n fig. 3 forecasts of oi l production and revenue: a) oil production; b) cash now. kuna (kn) is croatian money unit (i kn 0.2 us$). from kolundzic (1995) and galov rc (1996). 256 " "" .. "" " "" ~ " "" .= § "'" """ ''': i ~ ~ ~ a • total nel c&sh ::icw '''''' ,_~~~. __ ~~~~~~~_ ota... 25% """ "'" b rig. 4 forccasts of gas production and revenue: a) gas production; b) cash flow . from kolundzic (1995) and galovic ( 1996). s. conclusions exploration is a mult idimensional problem. the exp lore rs consider it from a professional, geo logical , developmental, technological and user's poin t of view. the management reach their final decisions on the basis or v~due ~lt1d scope of in vestmen t, rate of return and evaluation of risk. the owner or his representative is not usually an oilman. he rarely has any exp loration and/o r minin g sentiment and is additiona lly perplexed by the tim e component in the o il business. a time horizon rang ing from 5 to 20 years, necessity of inves tment cont inui ty , the scope of investmelll all these are the characteris­ tics which obstruct the vision. through providing a greater selec tion of exploration objectives (both within croatia and abroad) th an the planned scope of exploration, it is possible to establish, by comparative analysis, a priority between object ives . such basic data also enable comparative analyses with geologia croatica 49/2 ... ,.,. '''' " .. "'" "" "w fig. 5 trend of reduction of exploration and developmen t costs in usa (from artur andcrsen & co. , sc: hyd rocarbon value chain analysis. unpubli shed report , sept. 1995 , lna-narlaplin archive). i --production 1 ~~coveries and revisions y,1t ri g. 6 curves of growt h for production and discovery of reserves (from anur andersen & co., sc: hydrocarbon value chain analy sis.unpublished report, sept. 1995, ina-nartaplin archive). the prices of discovered reserves being offered for sale. iii addition to this, by pas t anal ysis, it can be eas il y proven that bot h exploration and production were a profitable business. through bc ttcr organization, and a choice of exploration objectives, the efficiency of exploration will be increased, probably with a new strategy of exploration as follows: intensify exploration abroad; increase the number of concess ions to 5-10; period toe drilling meters (m) efficiency coerf. 1945· 1954 727,370 232,492 3.1 3 1955-1964 7,668, 120 989,662 7.751 19651974 25,856,600 1,68 1,(j43 5.38 1975·1984 40,913,982 1,922,339 21.28 1945· 1984 75 , 167,431 4,825,536 15 .58 1985 4,606,911 239,646 19.22 1945· 1985 79,774,342 5,065,182 15 .75 table 7 efficiency of dri ll ing (from kolundz1c, 1995). kolullcizic: selection of e"plor~lt ion stralt.:gy 257 change (%) 1970 1975 1980 1985 1990 70·75 75·80 80·85 85·90 explor. drilling, m 48,863.0 71,319.0 60,379.0 89,282.0 82,000 7.9 3.3 8.1 .1.7 oil produclion, 10j i 2,057.1 2,669.7 3,056.4 3,059.2 2,696 5.4 2.7 0.0 -2.5 gas produc!., 106 rn' 477.7 7s 1.3 983.2 1,441.0 1,966 9.9 0.7 local prod. toe 2,534.8 3,421.0 4,039.6 4,500.2 4,662 product./elll p loyce 600 597 519 sis ("toe")/ernployee oil reserves a+b+c , i06 1 35 35 35 25 20 natural gas reserves lpg 10') m' 15 12 7 6 5 ng 109 ill) 12 15 30 22 40 table 8 production of somc basic products in the period from 1970 to 1990 and production per employee (from kolundzj<:, 1995). 1970 1980 1985 ina tolal 22.3 163.6 223.2 ina jp (public company) ' 12.0 199.8 280.8 i. ups tream 10.3 126.3 176.4 ii. processing 32.4 418 .8 369.0 iii. pelrochelll. 21.6 62 .0 81.2 define methods or evaluating a concession as well as the maximum and minim um participation; define (or delimit) the exploration as agreed with the owner including a proposal or reinvesting the entire profit to ihe year 2000. 6. references galov ic, s. (1996): the future of fossil fuel resourees.naita, 47/10, 275-294. iva nhoe, l.f. (1995): future world oil supplies: ihere is a rinite limil. world oil , october 1995, 7788. ivanhoe, l.f. (1996): updated i-iubberl curves ana­ lyze world oil supply.world oil, nov 1996,94. 1989 1990 118 .6 87.4 table 9 economic indicators of 139.8 101.1 productivity (1,000 us$) 89.6 61.1 total revenue per employee 162.7 126.4 (average value). ina lp (public company) was cnga71.2 48.0 gcd in thc core business of ina group. kolundzic , s. (1995): contribution to a complex modelling of system for production and market sup­ ply with natural gas.unpublished phd t hesis, university of zagreb. kvinnsland, o.j. (1993): worldwide act ivity will foclis on exploration appraisal.petrol. eng., viii/1993,26-32. ogj (i 987a): oil executives eye prospects [or erucle oil pr ice stability.report no.2, 12 wpc, ogj, may i i, 28-3 /. ogj (1987b): development stralegies for producers will focus on lower costs, hi g h recovery. ogj report, may ii , p. 37-40. 258 gcojogi'1 croatica 49(2 vlahovic et al.indd the karst dinarides are composed of relics of a single mesozoic platform: facts and consequences igor vlahović1, josip tišljar2, ivo velić1 and dubravko matičec1 1. introduction during the last two decades, a new concept appeared in the literature proposing the existence of two mesozoic carbonate platforms – dinaric and adriatic, separated by a deeper area – labile interplatform belt epiadriaticum (herak, 1986, 1989, 1991, 1993), which has unformally divided the croatian geological community into three groups. two relatively small groups of croatian and foreign researchers are directly involved in this problem and therefore have definite opinions, either supporting the idea of the existence of two platforms separated by a deeper basin during the mesozoic (fig. 1a – e.g. d’argenio et al., 1971; herak, 1986, 1989, 1991, 1993; radoičić, 1989a, b; cati et al., 1989; drobne & trutin, 1997; blašković, 2001), or opposing this concept, i.e. proclaiming that during the mesozoic this area represented a single, but more or less differentiated platform (fig. 1b – polšak, 1965b, 1981; jelaska, 1973; tišljar, 1983, 2001; buser, 1989; velić et al., 1989, 2002b; dercourt et al., 1993; gušić & jelaska, 1993; grandić et al., 1997, 1999; pamić et al., 1998, etc.), although frequently described under different names. the third group is the largest, comprising geologists who are not directly involved in this discussion. however, some of them use the proposed terms without adequate consideration. namely, although at first glance the problem of the existence of one or two carbonate platforms during the mesozoic seems like an exclusively scientific question, interesting only for a relatively small number of specialists, the practical meaning of the chosen concept is extremely important, not only for the regional geological framework, but also for study of the hydrogeology, engineering-geology and petroleum geology of the entire area. the aim of this paper is therefore to highlight the basic differences of the opposed concepts and analyse available material data on which they are founded. additionally, we will comment on the reasons for the significant dynamics of this carbonate body during the mesozoic, but we will also briefly discuss its duration and different names, suggesting which, in our opinion, is the best. geologia croatica 55/2 171–183 4 figs. zagreb 2002 key words: synsedimentary tectonics, palaeogeography, karst dinarides (external dinarides), lias to maastrichtian, adria microplate, adriatic carbonate platform, slovenia, croatia, bosnia and herzegovina, montenegro. 1 institute of geology zagreb, sachsova 2, hr-10000 zagreb, croatia; e-mail: igor.vlahovic@igi.hr 2 university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, hr-10000 zagreb, croatia. abstract croatian geological literature during the mid nineteen-eighties and nineties was marked by the appearance of a new geotectonic concept of the dinarides proposing that the recent, very complex structural setting is a direct consequence of a specific palaeogeographic relationship during the mesozoic, i.e. the proposed existence of two carbonate platforms separated by a long-lasting deep marine area (interplatform trough). although the idea was very interesting and provoked discussion, resulting in the questioning of formerly established concepts, detailed analysis of available data indicate that the karst dinarides (external dinarides) were formed by the destruction of a single, although morphologically considerably variable shallow water carbonate platform. this platform was in some periods very dynamic because of its palaeogeographic position during the mesozoic, resulting in many periods of large-scale facies differentiation, especially during the late cretaceous. the final disintegration of the platform area culminated in the formation of flysch trough(s) in the latest cretaceous and palaeogene and the subsequent uplift of the dinarides. recently there have been some misunderstandings resulting from the imprecise use of newly established terms, which are, by circular logic, used to connect recent geotectonic relationships with mesozoic palaeogeography without adequate material proof. therefore, the terms dinaricum and adriaticum should be redefined and used only for description of the recent tectonic pattern, without implying a palaeogeographic component, since during the mesozoic they represented a single entity. additional confusion is added by different names used for the same shallow water carbonate platform. probably the best, although not the ideal name is the most frequently used one: the adriatic carbonate platform. its duration may be estimated from the late lias to the late cretaceous, representing the most important part of a thick carbonate succession in the karst dinarides (ranging from carboniferous to eocene). 172 geologia croatica 55/2 173vlahović, tišljar, velić & matičec: the karst dinarides are composed of relics of... our goal is to present the material in a very straightforward way, enabling a wider audience to understand the fundamental differences between the proposed concepts and to become aware of the importance of the different concepts in the interpretation of the general geology of the area. 2. analysis of available data supporting the existence of two platforms the proposed concept of the existence of two mesozoic carbonate platforms practically means that from the late triassic to the eocene (herak, 1986, 1989, 1991, 1993) two individual carbonate platforms should have existed: the adriatic (geodynamic synonime adriaticum) and dinaric (geodynamic synonime dinaricum), separated by a long-lasting palaeogeographically deeper area, the interplatform trough epiadriaticum (fig. 1a), all on the same basement, i.e. adria microplate (dewey et al., 1973) or apulian promontory (ricou et al., 1986; dercourt et al., 1993). in the original papers, the similarity of the stratigraphic successions on both supposed platforms was explained by their relative proximity, i.e. the possibility of communication across a deeper area. the recent structural pattern of the karst dinarides (external dinarides), according to this concept, represents a consequence of collision and shallow subduction of the adriaticum below dinaricum, while deposits of a supposed labile trough (epiadriaticum) were mostly consumed during this process. the recent tectonic pattern of the dinarides is quite complex, where the geodynamic complex of adriaticum would generally correspond to the dalmatian zone of aubouin (1960) or to the adriaticum of sikošek & medwenitsch (1965) and the dinaricum to the high karst zone of kossmat (1924) or high dinaricum of sikošek & medwenitsch (1965), which are separated by major faults. the concept of herak (1986, 1989, 1991, 1993) refreshed an interest for a regional interpretation of the origin of the dinarides, especially of its strong mobilistic component, and therefore provoked significant scientific discussion. probably the key issue in this concept is an attempt to connect the original mesozoic palaeogeography with the regional geotectonic pattern of the dinarides which were formed by later destruction of the carbonate producing area, i.e. to undertake a multidisciplinary endeavour to connect the scope of interest of sedimentologists and palaeontologists dealing with mesozoic rocks with that of structural and regional geologists dealing with the recent structural pattern of the area. however, the key question for the critical analysis of the proposed concept is the validity of evidence for the continuous existence of a labile interplatform belt – epiadriaticum – the main prerequisite for the existence of two individual platforms is this deeper area separating them, i.e. without this area there are no separate platforms. this supposed deeper marine succession of the epiadriaticum should have a stratigraphic range from the late triassic to the eocene. in the original papers (herak, 1986, 1989, 1991, 1993) only some relatively small outcrops of kimmeridgian limestones (so-called “lemeš deposits” and correlative “limestones with cherts and ammonites”) and palaeogene flysch deposits were designated as deposits of supposed epiadriaticum in the area between budva and the slovenian troughs, and the rest is considered to be consumed under a regional nappe system. this means that from the entire supposed deep marine sequence, which, according to the international stratigraphic chart (ics, 2000), should have lasted almost 190 my, only 4 small outcrops of kimmeridgian and 15 outcrops of palaeogene deposits are preserved, representing only 11 my, or less than 6% of the time for sediment deposition. other mentioned outcrops belong to the marginal areas, and were influenced by the neighbouring open tethyan realm. in other words, for more than 94% of the duration of the supposed deep marine trough within the karst dinarides there is no material record. additionally, there are several other issues raising doubt on this concept. even if we accept the possibila b fig. 1 differences between a concept proposing the existence of two carbonate platforms (adriatic and dinaric) separated by a deep-marine realm (a), and the existence of a single adriatic carbonate platform (b) during the mesozoic. note shorter stratigraphic range proposed in this paper for (b) – see section 4. 172 geologia croatica 55/2 173vlahović, tišljar, velić & matičec: the karst dinarides are composed of relics of... ity that the most of the deposits of the supposed deeper marine trough were consumed during the subduction processes no traces of such rocks were documented in numerous wells drilled in the area of the dinarides during the last few decades. furthermore, such a long-lasting deeper marine area would probably have been surrounded by specific marginal facies along the platform rims, e.g. reefs, sand bars and material transported down the slopes, whether as debrites or turbidites. however, within the karst dinarides there are no outcrops of deposits of this type (excluding kimmeridgian deposits surrounding a short-lasting intraplatform trough formed by synsedimentary tectonics – velić et al., 1994, 2002a, or upper cretaceous deposits, when the platform area was already significantly differentiated – jelaska et al., 2000; velić et al., 2002b). there are no records of such deposits in numerous wells drilled in the area, and there are even no elements indicating such deposits on seismic profiles (where such specific facies within well-bedded platform carbonates would be very recognisable). additionally, supposed consummation of practically all deposits of the deeper-marine trough undoubtedly indicates large-scale horizontal movements within the dinarides, i.e. nappe structures, although recent structural investigations clearly indicate the predominance of relatively steep reverse faults (e.g. ćićarija mt., velebit mt., biokovo mt., etc.). from the structural point of view there is also a question of the possibility of having more or less circular outcrops of the aforementioned rocks, as presented in original papers, in the area characterised by strong collisional tectonics and clear linear orientation of structures. each of the aforementioned open questions, and especially when taken together, cast doubt on the possibility of the existence of a deeper marine area during such a long period, and in this way the possibility of the existence of two separate carbonate platforms. however, even if we would be able to find appropriate answers to these previous questions there is an additional, crucial one: whether the limited proposed deeper marine, i.e. intraplatform trough deposits (which are found in only 19 small outcrops, representing less than 6% of the complete duration of the supposed trough) could be undoubtedly attributed to this environment? such a supposed interplatform trough should be, by definition, characterised by continuous deeper marine deposition from the late triassic to the eocene. consequently, the main attribute of each sequence originating from this area has to be its continuous deeper marine succession, even if it is tectonized. velić et al. (1994, 2002a) and bucković (1995) studied sequences of kimmeridgian limestones with chert and ammonites proposed as epiadriaticum deposits in the original papers (herak, 1986, 1989, 1991). all the studied sequences are characterised by shallower marine underlying and overlying deposits, completely excluding the proposed origin – limestones with cherts and (very rare) ammonites were deposited within short-lasting intraplatform troughs (probable pull-apart basins) formed by synsedimentary tectonics, and which were gradually infilled by the progradation of perireefal material from its margins (fig. 2). a similar situation occurs with palaeogene outcrops proposed as epiadriaticum deposits – all deeper marine flysch deposits overlie shallow water foraminiferal limestones which are transgressive over cretaceous deposits of variable age. therefore, palaeogeographical variety during the palaeogene, when opposite coasts of the same flysch basin were characterised by different deposits and biota (e.g. drobne & trutin, 1997) has nothing to do with the palaeogeographic relationships during the mesozoic – it is the consequence of significant tectonic control, i.e. the final disintegration of the former platform area resulting in formation of the dinaridic mountain chain. furthermore, in the area where despite complex tectonics, the overlying sequence of deposits exists it is characterised by a clear regressive succession, from deep marine to shallow marine, coastal and alluvial deposits (so-called promina deposits). all the aforementioned arguments undoubtedly indicate that up to now there is an inadequate amount of material evidence to support the proposed concept of the existence of two platforms separated by a deep marine area from the late triassic to the eocene. therefore this concept, until supported by new evidence, can only be treated as hypothetical. we can conclude that the present day karst dinarides were formed by deformation of a single, but more or less differentiated mesozoic platform – commonly referred to as the adriatic carbonate platform (discussion on the name of the platform is given below), and that this mountain chain can be geotectonically subdivided into several geotectonic units. from the palaeogeographic point of view it is clear that the area of the platform was a very dynamic entity, both concerning its general shape (irregular outer margins and incised deeper trough in its nw part and budva–cukali trough in its se part – fig. 3) and very variable lateral and vertical alternation of platform facies. especially interesting is the fact that from the moment of its isolation in the late lias to its demise in the late cretaceous (discussed later) there were practically no periods when the entire platform was covered by the sea, i.e. without long-lasting terrestrial areas (i.e. islands) to a greater or lesser extent over the platform (tišljar et al., 2002). although the proposed terms adriaticum and dinaricum might be very attractive for a mere description of the recent structural pattern of the dinarides (and are often used in this sense, without much consideration, as handy synonyms for the adriatic zone and high karst 174 geologia croatica 55/2 175vlahović, tišljar, velić & matičec: the karst dinarides are composed of relics of... fig. 2 a different interpretation of kimmeridgian deposits: in the case of the existence of two carbonate platforms separated by a deep marine interplatform trough (a) all deposits of this deep basin should be of deep-marine origin (i.e. oxfordian, kimmeridgian and tithonian deposits should be deep-marine). however, kimmeridgian deposits of the gorski kotar area (upper part of the figure) indicate a different succession (b): shallow-marine oxfordian deposits are overlain by deeper-marine (not very deep) kimmeridgian deposits, i.e. limestone with chert deposited within the intraplatform trough, and this environment was gradually infilled by progradation of bioclastic material from its margins – tithonian deposits are again of typical shallow-marine origin (for details see velić et al., 2002a). a b sw ne sw ne 174 geologia croatica 55/2 175vlahović, tišljar, velić & matičec: the karst dinarides are composed of relics of... zone, respectively, which would correspond to their original definition by sikošek & medwenitsch, 1965) they should not be used in this way before their careful and complete redefinition or clear notification. namely, their definition in a palaeogeographic sense, i.e. as mesozoic palaeogeographic entities (herak, 1986, 1989, 1991) undoubtedly indicates their palaeogeographic origin as two individual platforms separated by a deeper marine realm, and their recent structural position therefore represents only a secondary characteristic. therefore, the authors have to be completely aware that even by using these terms only for description of the recent geotectonic setting they are inevitably indirectly indicating the existence of two different carbonate platforms during the mesozoic. 3. depositional dynamics of the platform one of the major characteristics of deposition in the area of the present day karst dinarides was the significant dynamics caused by palaeogeographic position on the mobile adria microplate. this mobility resulted in some periods of the platform history with important changes in its physiography, i.e. synsedimentary tectonic deformation has from time to time completely changed the large-scale facies distribution and architecture of this huge carbonate body, which was additionally eustatically controlled. some of the most dynamic periods in the geological history of the karst dinarides were: – middle triassic, when the adria microplate separated from gondwana (stampfli & mosar, 1999); – late lias, when a deep-marine trough connecting the ionian and belluno basins opened, resulting in the disintegration of the huge platform formed on the adria microplate foundation, and formation of the isolated adriatic, apulian and apenninic carbonate platforms (e.g. bernoulli, 1971; jelaska, 1973; zappaterra, 1990, 1994; grandić et al., 1999); – kimmeridgian, when completely different environments were established in the inner part of the platform (velić et al., 1994; tišljar et al., 1994), from transgression over emerged areas and formation of deeper intraplatform areas to emergence and formation of bauxite deposits (e.g. polšak, 1965b; natević & petrović, 1967; vujisić, 1972; vrhovčić et al., 1983; papeš, 1985; mirković & mirković, 1987; velić & tišljar, 1988; dozet & mišič, 1997; matičec et al., 2001, vlahović et al., 2001); fig. 3 the recent distribution of adriatic carbonate platform deposits on the mainland (grey) and under the adriatic sea (dark grey) – sw platform boundary after grandić et al. (1999), ne after velić et al. (2002b). the area was compressed significantly during the tertiary tectonic phase resulting in the uplift of the dinarides. also, note that despite the post-sedimentary tectonic deformation there is a continuous transition of the adriatic carbonate platform towards the southeast (into albania, greece and turkey) and probably towards the northwest (italy). adriatic carbonate platform (adcp) deposits 176 geologia croatica 55/2 177vlahović, tišljar, velić & matičec: the karst dinarides are composed of relics of... – late cretaceous, when significant differentiation of facies, which in some places had already begun in the early cretaceous (matičec et al., 1996), culminated in the establishment of laterally completely different successions (e.g. gušić & jelaska, 1990, 1993; vlahović et al., 1994; tišljar et al., 1998, 2001; korbar et al., 2001; velić et al., 2002b, etc.) and disintegration of the platform resulting in a complete emersion of variable duration (e.g. jelaska et al., 1994; ćosović et al., 1994; matičec et al., 1996); – tertiary, when continued deformation resulted in the formation of the flysch basin (mainly palaeocene and eocene) and the final collision in the area of the former carbonate platform (mainly oligocene– miocene), causing uplift of the dinaridic mountain chain and formation of the recent geotectonic pattern (lawrence et al., 1995). one of the arguments for the supposed existence of two mesozoic platforms separated by a deep-marine area was the recent structural pattern composed of two large-scale structural elements, usually referred to as the adriatic zone and high karst zone. therefore, a question arises as to how this structure could have been formed within a single platform area? the answer is connected with the geological history of the area: as previously mentioned, the late cretaceous and palaeogene periods were marked by the gradual disintegration of the platform, and formation of a labile belt, i.e. the flysch basin (or even several more or less parallel basins – dragičević & velić, 1994, 2002; velić et al., 2002b). continuation of strong compression of the area resulted in the formation of reversed structures and uplift of the hinterland, and in some places with the formation of nappe structures. steep planes of reverse faults (commonly more than 70º) were probably the consequence of inverse tectonics, i.e. reactivation of inherited structures – lineaments from the platform foundation. however, the recent structural pattern of dinarides is very complex, and the main structural discontinuities are not only located on the boundaries between the large-scale structural units of the adriatic zone (or adriaticum in herak’s concept) and the high karst zone (or dinaricum in herak’s concept), but also within them (e.g. the una–knin–drniš–sinj–jabuka–buško blato tectonic line in the hinterland, where upper permian and upper eocene/oligocene rocks are in direct contact). this requires additional tectonic interpretation which is beyond the scope of this paper, which deals primarily with the palaeogeographical aspect of the karst dinarides area. therefore, we could conclude the following succession of main events in the evolution of the karst dinarides area: 1) deposition of mixed carbonate–clastic sediments on an epeiric carbonate platform along the northern gondwana margin during the palaeozoic and early triassic. 2) an initiation phase characterised by the formation of steep faults in the basement and separation of the adria microplate (midle triassic); 3) a platform phase (from late triassic to late lias as a huge united platform on the adria microplate basement, from the late lias as an isolated adriatic carbonate platform) with temporary synsedimentary deformation which were reinforced towards the end of the cretaceous; 4) a disintegration phase characterised by the establishment of flysch basin(s) from the late cretaceous, and especially in the palaeogene (middle to late eocene); 5) tectonic contraction of the platform area resulting in the uplift of the dinarides (oligocene–miocene). 4. stratigraphic span of the platform the other important but complex issue needing significant reconsideration is the question of the stratigraphic span of the adriatic carbonate platform. during its evolution this huge carbonate body passed through different phases as a consequence of the previously mentioned significant dynamics caused by its palaeogeographic position. however, only one part although the significant one, of the entire carbonate sequence which is today incorporated into the karst dinarides (external dinarides), can be attributed to the isolated adriatic carbonate platform. the first significant carbonate deposition documented in the area of the karst dinarides was of permian age (occurrences of carboniferous carbonates are very restricted), when a thick sequence of limestones and dolomites in lateral and vertical alternation with clastic deposits and evaporites was deposited in central dalmatia, bosnia and lika (šušnjara et al., 1992; tišljar, 1992) in the form of an epeiric carbonate platform of the northern gondwana margin (fig. 4a). during the early triassic, siliciclastic environments prevailed, while in the middle triassic carbonate facies with locally significant volcanoclastic influence were deposited. it is supposed that this was a period of separation of the adria microplate from the gondwana (stampfli & mosar, 1999), based on these regionally important occurrences and mainly clastic deposition in the carnian. this event might be interpreted as the beginning of the existence of the isolated, intraoceanic carbonate platform, since the area was no more under the influence of the continental environments (fig. 4b). however, the late triassic succession of the so-called main dolomite (hauptdolomit, dolomia principale) and dachstein limestones represents a regional event characteristic for the very wide region of central and eastern europe. undoubtedly during this period the studied area represented only a part of a larger shallow water 176 geologia croatica 55/2 177vlahović, tišljar, velić & matičec: the karst dinarides are composed of relics of... carbonate platform, being connected, e.g. with the area of the future apulian and apenninic platforms. the very beginning of the existence of the adriatic carbonate platform as a palaeogeographical entity unfortunately cannot be documented in the investigated area of the karst dinarides, (because of the practically continuous inner platform shallow-water deposition from the late triassic – the margins of the platform are today covered by the adriatic sea), but in contemporaneous deposits drilled in the offshore wells in the adriatic, there is clear evidence of the important event which took place in the middle and late lias (bernoulli, 1971; jelaska, 1973; zappaterra, 1990, 1994; grandić et al., 1999). in these wells, which are located near the platform margin, a succession from shallow water triassic and early to middle lias deposits to the basinal upper lias and later rocks was documented – suggesting that during the late lias the adria microplate was segmented into smaller carbonate platforms and the new adriatic basin was formed (fig. 4c), connecting deeper marine areas of the belluno basin to the north with the ionian basin to the south. along the margins of this basin new carbonate platforms were born: the apulian and apenninic carbonate platforms along the western coast of the basin and the adriatic carbonate platform along its eastern side. the south-western margin of the adriatic carbonate platform is today covered by the recent adriatic sea, and can only be studied by geophysical methods and analysis of offshore wells. in contrast, the ne platform margin is exposed in the area of žumberak mt., samoborska gora mt. and karlovac area. individualization of the platform is also recorded in the late lias (radoičić, 1966; gušić & babić, 1970; bukovac et al., 1974, 1984; šikić & basch, 1975; babić, 1976; pleničar et al., 1976; šikić et al., 1978; šparica, 1981; bukovac & sokač, 1989; velić et al., 2002b). however, dragičević & velić (2002), indicate that initial events connected with formation of the later ne margin of the adriatic carbonate platform had already started in the early lias (late sinemurian). although the adriatic carbonate platform was mostly characterised by the profuse production of carbonates in predominately typical shallow water environments of the inner part of the platform, it was, during its history, commonly morphologically differentiated as a consequence of the interaction of eustatic sea-level changes and the important influence of synsedimentary tectonic deformation (polšak, 1965a, b; jelaska, 1973; tišljar et al., 1983; gušić & jelaska, 1990, 1993; tišljar & velić, 1991; vlahović et al., 1994, etc.). these events caused formation of temporary intraplatform lagoons and small basins (e.g. in kimmeridgian – velić et al., 1994, 2002a; bucković, 1995), occurrences of local or regional emersions in the malm (e.g. polšak, 1965a; natević & petrović, 1967; vujisić, 1972; bukovac et al., 1974, 1984; vrhovčić et al., 1983; mirković & mirković, 1987; velić & tišljar, 1988; tišljar et al., 1989, 1994; dozet & mišič, 1997) or near the aptian/albian transition (velić et al., 1989; tišljar & velić, 1991), as well as temporary drowning of the platform (e.g. in large parts of the platform near the cenomanian/turonian transition – gušić & jelaska, 1990, 1993; jenkyns, 1991; vlahović et al., 1994, 2002). it is important to notice that the morphological differentiation was progressively more well expressed in the late cretaceous, when laterally different environments were established, from islands, spacious shallow-water areas to deeper parts, lagoons and carbonate ramps. at the end of the cretaceous, the major part of the platform emerged (except for its ne margin which was drowned during the late cretaceous and characa b c sw ne fig. 4 schematic illustration showing the main events before the separation of the adriatic carbonate platform: (a) until the middle triassic rifting the study area represented a part of the epeiric platform located along the northern gondwana margin; during this event the adria microplate or apulian promontory was separated, and a huge isolated platform was formed (b), which was partly disintegrated during the late lias, resulting in formation of the adriatic basin (ab) and molise–lagonero basin (not shown), and the final separation and isolation (c) of the adriatic carbonate platform (adcp), the apulian carbonate platform (apcp) and the apenninic carbonate platform (not shown). 178 geologia croatica 55/2 179vlahović, tišljar, velić & matičec: the karst dinarides are composed of relics of... terised by continuous flysch deposition from the late cretaceous to the palaeogene – see dragičević & velić, 2002 this vol.), but the duration of this phase was very variable over different parts of the platform (e.g. see ćosović et al., 1994). this event might be considered as the end of the adriatic carbonate platform, since renewed carbonate deposition in the palaeogene was largely controlled by regional tectonics, and areas of primary carbonate production were gradually overwhelmed by clastic deposition. the palaeogene succession commenced in the eocene (palaeocene deposits are practically missing in the inner part of the former platform – drobne, 1977; drobne et al., 1991; ćosović & drobne, 1998; velić et al., 2002b), with a transgression over very differentiated palaeorelief, resulting in significant lateral and vertical facies changes over small distances. carbonate deposition took place along spatially restricted, relatively narrow carbonate ramps surrounding flysch basin(s) which were contemporaneously formed by intense tectonic compression of the area. a major part of the material was produced by large benthic foraminifera (miliolids, alveolinids, nummulitids and discocyclinids), and these deposits are therefore known as foraminiferal limestones. their net sedimentation rate was quite low, partly because of the probably originally slower carbonate production (major carbonate producers like green algae are practically missing in this primarily foramol type association), and partly because of the important reworking and transport of material towards the deeper parts of the contemporaneously forming basin(s). carbonate production was incapable of keeping pace with the strong tectonic deformations which were significantly changing palaeogeographical relationships. therefore the areas of carbonate production were generally retreating, and in this retrogradational sequence they were substituted by deeper marine environments, first “globigerina marls” and than flysch deposits. however, reconstruction of the palaeogene palaeogeography is complicated both by the important role of synsedimentary tectonics which caused formation of the palaeogene foreland basins and by the very complicated recent structural pattern. from the above discussion it is obvious that both temporal boundaries of the adriatic carbonate platforms cannot be easily and unequivocally defined. however, on the basis of present knowledge probably the best approximation of its duration would be a stratigraphic range from the late lias to the end of the cretaceous, when the adriatic carbonate platform was completely isolated (i.e. surrounded by other platforms having specific names) and characterised by massive carbonate production resulting in a huge pile of practically pure carbonate deposits. in this definition common incorporation of carbonate deposits of wider stratigraphic range (e.g. permian to eocene – tišljar et al., 1991; velić, 2000; velić et al., 2002b; or late triassic to eocene – pamić et al., 1998), originating from different palaeogeographic patterns, into the same palaeogeographic entity, would be avoided. this area was bounded by the ionian, adriatic and belluno basins, as well as by eastern tethys, and its continuity towards the south is characterised by narrowing in the area of montenegro and albania (which is practically defined as the boundary of the adriatic carbonate platform), but relics of the larger mesozoic platform can also be found in albania (kruja platform), greece (gavrovo and tripolitza platforms) and turkey (menderes platform). therefore, by the cenozoic, tectonic relics of the carbonate platform (parts of which are known under different names) became part of the mountain ranges of the dinarides, albanides, hellenides and taurides. it is obvious that in this way, the defined adriatic carbonate platform does not comprise all of the important carbonate successions of the karst dinarides. underlying deposits comprise mixed permian to lower triassic clastic–carbonate deposits of the epeiric platform spreading along the northern gondwana margins, thick middle triassic limestones, as well as upper triassic to middle lias carbonates representing a part of the huge periadriatic carbonate platform covering the adria microplate drifting from gondwana after the middle triassic segmentation (pamić et al., 1998). overlying deposits comprise a succession of palaeogene foraminiferal limestones and flysch deposits which are mostly composed of carbonate clasts. 5. the name of the carbonate platform of the karst dinarides the name of the mesozoic carbonate platform, the disintegration of which provided the material for the dinarides is also an interesting question. although this platform was referred to by several different names (see tišljar et al., 2002, for some of the terms), those most recently used are the dinaric carbonate platform, adriatic–dinaric carbonate platform and adriatic carbonate platform, and therefore these are the only ones discussed here. the main argument for usage of the term dinaric carbonate platform is its apparent geographic connotation, because the rocks of the mesozoic platform represent a part of the dinaridic mountain range. however, there are several counterarguments: (1) the dinarides are, in a large part, composed of rocks which did not originate on the mesozoic carbonate platform, e.g. pre-platform clastic and carbonate rocks (palaeozoic, triassic and lower jurassic), eocene clastic and carbonate rocks, neogene clastic rocks, postsedimentary breccias, different types of magmatic and metamorphic rocks and quaternary deposits. additionally, most of the highest mountains in the dinaridic mountain range are located within the so-called inner dinarides, i.e. within the ne part of the dinaridic mountain range 178 geologia croatica 55/2 179vlahović, tišljar, velić & matičec: the karst dinarides are composed of relics of... which is genetically not connected to the mesozoic carbonate platform. (2) the temporal designation of this term is erroneous: the dinarides, which would represent a source for the designation of the platform, were produced by tectonic events which culminated in the oligocene– miocene (i.e. there were no dinarides before that period). therefore, the platform would be named after the mountain range formed more than 160 my after the beginning of the platform existence and 30–40 my after the end of the platform existence. (3) usage of this term inevitably causes confusion between the name of the platform and the product of its disintegration, and therefore possible misinterpretation of many phrases including “dinaric units” or “dinaric elements” which in theory, could refer either to the original mesozoic platform or the recent tectonic pattern. the mixed term adriatic–dinaric carbonate platform, used by some authors, is potentially confusing, since: (1) the second part of the name also implies all the aforementioned problems connected with the term “dinaric”, especially concerning its temporal dimension; (2) as a composite term it might confuse uninitiated readers on the possible existence of two platforms united into one (although in their original papers the authors have clearly indicated that they consider this area to be a united palaeogeographic entity, i.e. a single carbonate platform – e.g. gušić & jelaska, 1993; jelaska et al., 1994). the name adriatic carbonate platform is probably the best, although not the ideal one (since the term “adriatic” might include the entire adriatic area, i.e. both coasts). however, carbonate platforms which are located along the sw coast of the adriatic sea, and which have the same foundation as the platform studied in this paper since they were formed on the adria microplate after its disintegration in the late lias, have their specific names – apulian and apenninic carbonate platforms. concerning the temporal dimension this name for the platform would be definitely the most appropriate: the adriatic basin connecting deeper marine areas of the ionian and belluno basins, i.e. precursor of todays adriatic sea, was formed in the late lias, and therefore the entire succession of the investigated mesozoic carbonate platform was formed along the ne coast of this ancient deep marine trough. finally, this name would keep the priority of polšak’s (1965b) designation, since he called the entire shallow marine area which by its disintegration formed the karst dinarides (external dinarides) as the “adriatic zone”, and later as the “adriatic plate (“carbonate platform”)” (polšak, 1981), resulting in later establishment of the name “adriatic carbonate platform” (gušić & jelaska, 1990). although this name of the platform has previously been shortened to “acp” a better acronym would be “adcp”, since “acp” is commonly used as an abbreviation for the apenninic carbonate platform. 6. conclusion on the basis of the critical analysis of the available arguments for the supposed continuous existence of two separate platforms and a deeper marine area between them from the late triassic to the eocene we may conclude: – from the supposed complete sequence of deep marine succession only outcrops of kimmeridgian and palaeogene age have been found, i.e. for 94% of the supposed duration there is no adequate material evidence; – deep marine deposits of other stratigraphic periods have not been found in deep wells within the karst dinarides area; – at the surface, in the wells or on seismic profiles over the entire karst dinarides area (which comprise the supposed adriaticum, epiadriaticum and dinaricum geotectonic units) there are no elements indicating marginal platform facies (reefal/perireefal bodies, sand bars, slope deposits and turbidites) towards the supposed interplatform area; – the recent tectonic pattern of the dinarides is predominantly characterised by relatively steep reverse faults, and not by nappe structures with significant horizontal movements necessary for consumption of the supposed deep-marine deposits; – detailed analysis of outcrops of the supposed intraplatform deposits indicate that their underlying deposits (in the case of palaeogene flysch deposits) or both underlying and overlying deposits (in the case of the kimmeridgian limestones with cherts and ammonites and palaeogene flysch deposits with visible overlying deposits) are of the shallow-marine origin. these facts exclude their possible origin within continuous deep marine environments of the supposed interplatform trough. on the basis of these presented facts we can, according to the up to now available data, conclude that the area of the karst dinarides was formed by the tectonic disintegration of a single, but throughout the period of its existence, a more or less morphologically variable shallow-marine carbonate platform. the supposed existence of two platforms divided by a deep marine interplatform area from the late triassic to the eocene, cannot be theoretically excluded, but at present there is no adequate material evidence to support it. this single carbonate platform was very dynamic because of its specific palaeogeographic position, 180 geologia croatica 55/2 181vlahović, tišljar, velić & matičec: the karst dinarides are composed of relics of... resulting in several episodes of large-scale facies differentiation during its history. the dynamics of events in the platform area increased in the late cretaceous, and culminated in the cenozoic by the formation of flysch troughs and the final uplift of the dinarides, i.e. the formation of the recent tectonic pattern. however, this recent tectonic pattern cannot be uncritically equated with depositional basins during the mesozoic, which is a common misconception. there are discrepancies concerning the name of the mesozoic platform of the present karst dinarides – we consider that the best, although not an ideal term, is the adriatic carbonate platform. according to the regional events and palaeogeography of the platform it may be concluded that the most appropriate time-span for its existence is a stratigraphic range from the late lias to the late cretaceous. however, it is obvious that the platform defined in this way cannot include all carbonate deposits occurring in the area of the karst dinarides: relatively large quantities of carbonates were also deposited during the late permian, triassic, early jurassic and the eocene. it may be concluded that on the foundation of the adria microplate during the mesozoic, a single, but morphologically variable adriatic carbonate platform (adcp) was formed, and its disintegration in the cenozoic resulted in the formation of the dinaridic mountain chain. acknowledgement the authors are sincerely grateful to the reviewers, professor vladimir jelaska (faculty of sciences, university of zagreb) and dr. bojan ogorelec (geological survey of slovenia), for their comments and useful suggestions. 7. references aubouin, j. (1960): essai sur l’ensemble italo-dinarique et ses rapports avec l’arc alpin.– bull. sci. géol. france, 7/2, ii, 487–526. babić, lj. (1976): pomak granice između unutrašnje i vanjske dinarske regije, primjer šireg područja žumberka (migration of the boundary between “inner” and “outer” dinaric zones).– zbornik radova 8. jugosl. geol. kongresa bled (1974), ljubljana (proceedings of the 8th yugosl. geol. congress), 2, 45–51. bernoulli, d. (1971): redeposited pelagic sediments in the jurassic of the central mediterranean area.– annales instituti geologici publici hungarici, 54/2, 71–90. blašković, i. (2001): međuplatformni mobilni pojas – nužnost u objašnjenju kinematike formiranja recentnih tektonskih odnosa u obalnom području vanjskih dinarida (interplatform mobile belt – necessity for the explanation of the kinematics of formation of the recent tectonic relations in the coastal area of the external dinarids).– in: dragičević, i. & velić, i. (eds.): 1. znanstveni skup “karbonatna platforma ili karbonatne platforme dinarida” (first scientific meeting ”carbonate platform or carbonate platforms of dinarids”), zagreb october 2001, abstracts (in croatian), 65. bucković, d. (1995): upper jurassic carbonate facies succession at breze (velika kapela, croatia).– geol. croatica, 48/1, 9–16. bukovac, j. & sokač, b. (1989): upper triassic–lower liassic limestones on the northern slopes of mt. gorjanci and south of kostanjevica (southeast slovenia) and their significance for the geotectonics of the larger area.–geol. vjesnik, 42, 7–13. bukovac, j., velić, i. & sokač, b. (1974): stratigrafski, tektonski i paleogeografski odnosi u području dugarese, barilovića i skradske gore (stratigraphy, tectonics and palaeogeography of the region between duga resa, barilović and skradska gora, croatia).– geol. vjesnik, 27, 59–77. bukovac, j., šušnjar, m., poljak, m. & čakalo, m. (1984): osnovna geološka karta sfrj 1:100.000. list črnomelj l33–91 (basic geological map sfry 1: 100.000, the črnomelj sheet).– geološki zavod zagreb, geološki zavod ljubljana (1983), savezni geološki zavod beograd. buser, s. (1989): development of the dinaric and the julian carbonate platforms and of the intermediate slovenian basin (nw yugoslavia).– mem. soc. geol. ital., 40, 313–320. cati, a., sartorio, d. & venturini, s. (1989): carbonate platforms in the subsurface of the northern adriatic area.– mem. soc. geol. ital., 40, 295–308. ćosović, v. & drobne, k. (1998): lutetian orthophragminae from the istrian peninsula (adriatic sea, croatia and slovenia).– dela-opera sazu 4 razr., 34/2, 173–181, ljubljana. ćosović, v., balončić, d., koić, m., marjanac, t., moro, a., gušić, i. & jelaska, v. (1994): paleontological evidence of paleogene transgression on adriatic carbonate platform.– géologie méditerranéenne, 21/3–4, 49–53. d´argenio, b, radoičić, r. & sgrosso, i. (1971): a paleogeographic section through italo–dinaric external zones during jurassic and cretaceous times. nafta, 22/ 4–5, 195–207. dercourt, j., ricou, l.e. & vrielynck, b. (eds.) (1993): atlas tethys palaeo-envinronmental maps.– gauthier–villars, paris, 307 p. dewey, j.f., pitman, w.c., ryan, w.b.f. & bonnin, j. (1973): plate tectonics and evolution of the alpine system.– bull. geol. soc. am., 84, 3137–3170. dozet, s. & mišič, m. (1997): on malm bauxites and adjacent carbonate rocks in suha krajina (central slovenia).– rudarsko–metalurški zbornik, 44/3–4, 201–222, ljubljana. dragičević, i. & velić, i. (1994): stratigraphical position and significance of reef facies at the northern margin of the dinaric carbonate platform during the late jurassic 180 geologia croatica 55/2 181vlahović, tišljar, velić & matičec: the karst dinarides are composed of relics of... and cretaceous in croatia and bosnia.– géologie méditerranéenne, 21/3–4, 59–63. dragičević, i. & velić, i. (2002): the northeastern margin of the adriatic carbonate platform.– geol. croatica, 55/2, 185–232. drobne, k. (1977): alveolines paleogenes de la slovenie et de l’istrie.– mem. suiss. paleont., 99, 175 p. drobne & trutin (1997): alveolinas from the bunić section.– geol. croatica, 50/2, 215–223. drobne, k., vlahović, i., trutin, m., pavlovec, r., ćosović, v., babac, b., cimerman, f., lučić, d. & pavšič, j. (1991): excursion b – ravni kotari – paleogen.– in: vlahović, i. & velić, i. (eds.): some aspects of the shallow water sedimentation on the adriatic carbonate platform (permian to eocene). excursion guide–book, 2nd internat. symposium on the adriatic carbonate platform, institute of geology, zagreb, 53–107. grandić, s., boromisa-balaš, e. & šušterčić, m. (1997): exploration concept and characteristic of the dinarides stratigraphic and structural model in the croatian offshore area, part 1.– nafta, 48/4, 117–128, zagreb. grandić, s., boromisa-balaš, e., šušterčić, m. & kolbah, s. (1999): hydrocarbon possibilities in the eastern adriatic slope zone of croatian offshore area.– nafta, 50/2, 51–73, zagreb. gušić, i. & babić, lj. (1970): neke biostratigrafske i litogenetske osobine jure žumberka (some biostratigraphic and lithogenetic characteristic of the jurassic in žumberak, northwest croatia).– geol. vjesnik, 23, 39–54. gušić, i. & jelaska, v. (1990): stratigrafija gornjokrednih naslaga otoka brača u okviru geodinamske evolucije jadranske karbonatne platforme (upper cretaceous stratigraphy of the island of brač within the geodynamic evolution of the adriatic carbonate platform).– jazu and inst. geol. istraživanja, zagreb,160 p. gušić, i. & jelaska, v. (1993): upper cenomanian– lower turonian sea-level rise and consequences on the adriatic–dinaric carbonate platform.– geol. rundschau, 82/4, 676–686. herak, m. (1986): a new concept of geotectonics of the dinarides.– acta geologica, 16/1, 1–42. herak, m. (1989): relationship between adriatic and dinaric platforms.– mem. soc. geol. ital., 40, 289–293, roma. herak, m. (1991): dinarides – mobilistic view of the genesis and structure.– acta geologica, 21/2, 35–117, zagreb. herak, m. (1993): additional considerations on the epiadriaticum, outer dinarides.– geol. croatica, 46/1, 165–168. ics (2000): international stratigraphic chart.– international union of geosciences – commission on the geological map of the world. jelaska (1973): paleogeografska i naftnogeološka razmatranja zapadnog dijela karbonatnog šelfa dinarida (paleogeographic and oil-geologic considerations of the west part of the dinaride carbonate shelf).– geol. vjesnik, 25, 57–64. jelaska, v., gušić, i., jurkovšek, b., ogorelec, b., ćosović, v., šribar, l. & toman, m. (1994): the upper cretaceous geodynamic evolution of the adriatic–dinaric carbonate platform(s).– geol. méditerranéenne, 21/3–4, 89–91. jelaska, v., benček, đ., ćosović, v., gušić, i. & matičec, d. (2000): upper cretaceous–paleogene resedimented carbonates: their significance for the dynamics of the adriatic–dinarids carbonate platform.– symposium quantitative models on cretaceous carbonates and the eastern margin of the apulia platform. vieste–gargano, italy, september 2000, abstract book, 12. jenkyns, h.c. (1991): impact of cretaceous sea-level rise and anoxic events on mesozoic carbonate platform of yugoslavia.– am. ass. petrol. geol. bull., 75, 1007–1017. korbar, t., fuček, l., husinec, a., vlahović, i., oštrić, n., matičec, d. & jelaska, v. (2001): cenomanian carbonate facies and rudists along shallow intraplatform basin margin – the island of cres (adriatic sea, croatia).– facies, 45, 39–58. kossmat, f. (1924): geologie der zentralen balkanhalbinsel. mit einer übersicht des dinarischen gebirgsbaues.– in: wilser, j. (ed.): die kriegsschauplätze 1914-1918 geologisch dargestellt. h.12, gebruder borntraeger berlin, 198 p. lawrence, s.r., tari-kovačić, v. & gjukić, b. (1995): geological evolution model of the dinarides.– nafta, 46/2, 103–113, zagreb. matičec, d., vlahović, i., velić, i. & tišljar, j. (1996): eocene limestones overlying lower cretaceous deposits of western istria (croatia): did some parts of present istria form land during the cretaceous?– geol. croatica, 49/1, 117–127. matičec, d., vlahović, i., velić, i. & tišljar, j. (2001): sinsedimentacijska tektonika na jadranskoj karbonatnoj platformi (synsedimentary tectonics on the adriatic carbonate platform).– in: dragičević, i. & velić, i. (eds.): 1. znanstveni skup “karbonatna platforma ili karbonatne platforme dinarida” (1st scientific meeting “carbonate platform or carbonate platforms of dinarids”), knjiga sažetaka (abstracts), 46–50, zagreb. mirković, m. & mirković, b (1987): novi podaci o rasprostranjenju jurskih sedimenata u području sinjavine, durmitora i ljubišnje (new data about distribution of jurassic sediments in the area of sinjavina, durmitor and ljubišnja).– geološki glasnik, 12, 61–87, titograd. natević, lj. & petrović, v. (1967): osnovna geološka karta sfrj 1:100.000. list trebinje (basic geological map sfry 1:100.000, the trebinje sheet) k 34–37.– geološki zavod sarajevo (1963), savezni geološki zavod beograd. pamić, j., gušić, i. & jelaska, v. (1998): geodynamic evolution of the central dinarides.– tectonophysics, 297, 251–268. papeš, j. (1985): geologija jugozapadne bosne (geology of the southwestern bosnia).– geol. glasnik, pos. izd. (spec. publ.), 19, sarajevo, 197 p. pleničar, m., premru, u. & herak, m. (1976): osnovna geološka karta sfrj 1:100.000. list novo mesto l33– 79 (basic geological map of sfry 1:100,000. the novo mesto sheet).– geološki zavod ljubljana (1963–1969), savezni geološki zavod beograd. 182 geologia croatica 55/2 183vlahović, tišljar, velić & matičec: the karst dinarides are composed of relics of... polšak, a. (1965a): stratigrafija jurskih i krednih naslaga srednje istre (stratigraphie des couches jurassiques et crétacées de l’istrie centrale).– geol. vjesnik, 18/1, 167– 184, zagreb polšak, a. (1965b): geologija južne istre s osobitim obzirom na biostratigrafiju krednih naslaga (géologie de ľistrie méridionale spécialements par rapport é la biostratigraphie des couches crétacées).– geol. vjesnik, 18/2, 415–510. polšak, a. (1981): upper cretaceous biolithitic complexes in a subduction zone: examples from the inner dinarides, yugoslavia.– sepm, spec. publ., 30, 447–472. radoičić, r. (1966): microfaciès du jurasique des dinarides externes de la yougoslavie.– geologija, 9, 5–378. radoičić, r. (1989a): the dinaric carbonate platform: adjacent basins and depressions.– mem. soc. geol. it., 40, 309–311. radoičić, r. (1989b): preplatform and first carbonate platform development stages in the dinarides (montenegro– serbia sector, yugoslavia).– mem. soc geol. it., 40, 355–358. ricou, e.l., dercourt, j., geyssant, j., grandjacquet, c., lepurier, c. & biju-duval, b. (1986).– geologic constraints on the alpine evolution of the mediterranean tethys.– tectonophysics, 234, 73–94. sikošek, b. & medwenitsch, w. (1965): neue daten zur fazies und tektonik der dinariden.– verh. geol. bundesanst., sonderheft g., 86-102. stampfli, g.m. & mosar, j. (1999): the making and becoming of apulia.– in: gosso, g., jadoul, f., sella, m. & spalla, m.i. (eds.): 3rd workshop on alpine geological studies. memorie di scienze geologiche, 51/1, 141–154, padova. šikić, k. & basch, o. (1975): geološka zbivanja od paleozoika do kvartara u zapadnom dijelu zagrebačke regije (geological events from paleozoic to quaternary in the western part of zagreb area).– 2. godišnji znanstveni skup sekcije za primjenu geol., geofiz., geokem., znanstveni savjet za naftu jazu zagreb (a), 5, 69–86. šikić, k., basch, o. & šimunić, a. (1978): osnovna geološka karta sfrj 1:100.000. list zagreb l33–80 (basic geological map of sfry 1:100,000. the zagreb sheet).– institut za geološka istraživanja zagreb (1972), savezni geološki zavod beograd. šparica, m. (1981): mezozoik banije, korduna i dodirnog područja bosne (geology of the mesozoic areas of kordun, banija and nw bosnia, yugoslavia).– nafta, zagreb, spec. publ., xii+245 p. šušnjara, a., sakač, k., jelen, b. & gabrić, a. (1992): upper permian evaporites and associated rocks of dalmatia and borderline area of lika and bosnia.– geol. croatica, 45, 95–115. tišljar, j. (1983): coated grains facies in the lower cretaceous of the outer dinarides (yugoslavia).– in: peryt, t. (ed.): coated grains. springer-verlag, berlin–heidelberg–new york–tokyo, 566–576. tišljar, j. (1992): origin and depositional environments of the evaporite and carbonate complex (upper permian) from the central part of the dinarides (southern croatia and western bosnia).– geol. croatica, 45, 115–127. tišljar, j. (2001): sedimentologija karbonata i evaporita (sedimentology of carbonates and evaporites – in croatian).– institute of geology, zagreb, 375 p. tišljar, j. & velić, i. (1991): carbonate facies and depositional environments of the jurassic and lower cretaceous of the coastal dinarides (croatia).– geol. vjesnik, 44, 215–234. tišljar, j., velić, i. & sokač, b. (1983): flachwasserkarbonate der unterkreide im dinarischen karstgebiet entlang der adriaküste.– zitteliana, 10, 201–206, münchen. tišljar, j., velić, i. & sokač, b. (1989): einflüsse von emersionen auf die flachwasser-karbonatsedimentation im malm (ober jura) des biokovo-gebirges (südkroatien, jugoslawien).– geol. paläont. mitt. innsbruck, 16, 199– 202. tišljar, j., vlahović, i., sremac, j., velić, i., veseli, v. & stanković, d. (1991): excursion a – velebit mt., permian–jurassic.– in: vlahović, i. & velić, i. (eds.): some aspects of the shallow water sedimentation on the adriatic carbonate platform (permian to eocene), excursion guide-book. the second international symposium on the adriatic carbonate platform – relations with adjacent regions, 1–49, zagreb. tišljar, j., velić, i. & vlahović, i. (1994): facies diversity of the malmian platform carbonates in western croatia as a consequence of synsedimentary tectonics.– géologie méditerranéenne, xxi/3–4, 173–176. tišljar, j., vlahović, i., velić, i., matičec, d. & robson, j. (1998): carbonate facies evolution from the late albian to middle cenomanian in southern istria (croatia): influence of synsedimentary tectonics and extensive organic carbonate production.– facies, 38, 137–152. tišljar, j., velić, i. & vlahović, i. (2001): makrofacijesi gornjotrijaskih, jurskih, krednih i paleogenskih platformnih karbonata krškog područja dinarida (upper triassic, jurassic, cretaceous and palaeogene carbonate platform deposits in the karst dinarides).– in: velić, i. & dragičević, i. (eds.): 1. znanstveni skup “karbonatna platforma ili karbonatne platforme dinarida” (1st scientific meeting “carbonate platform or carbonate platforms of dinarids”), knjiga sažetaka (abstracts), 38–40, zagreb. tišljar, j., vlahović, i., velić, i. & sokač, b. (2002): carbonate platform megafacies of the jurassic and cretaceous deposits of the karst dinarides.– geol. croatica, 55/2, 139–170. velić, i. (2000): the karst dinarides: the adriatic carbonate platform or carbonate pie up to 8.000 m thick, built through the period of more than 200 milions of years.– in: carulli, g.b. & longo salvador, g. (eds.): riassunti delle comunicazioni orali e di poster. 80. riunione estiva, trieste 2000, soc. geol. it., 452–455. velić, i. & tišljar, j. (1988): litostratigrafske jedinice u dogeru i malmu zapadne istre (zapadna hrvatska, jugoslavija) (lithostratigraphic units in the dogger and malm of western istria, western croatia).– geol. vjesnik, 41, 25–49. 182 geologia croatica 55/2 183vlahović, tišljar, velić & matičec: the karst dinarides are composed of relics of... velić, i., tišljar, j. & sokač, b. (1989): the variability of thicknesses of the barremian, aptian and albian carbonates as a consequence of changing depositional environments and emersions in western istra (croatia, yugoslavia).– mem. soc. geol. ital., 40, 209–218. velić, i., vlahović, i. & tišljar, j. (1994): late jurassic lateral and vertical facies distribution: from peritidal and inner carbonate ramps to perireefal and peritidal deposits in se gorski kotar (croatia).– géologie méditerranéenne, 21/3–4, 177–180. velić, i., tišljar, j., vlahović, i., velić, j., koch, g. & matičec, d. (2002a): palaeogeographic variability and depositional environments of the upper jurassic carbonate rocks of velika kapela mt. (gorski kotar area, adriatic carbonate platform, croatia).– geol. croatica, 55/2, 121–138. velić, i., vlahović, i. & matičec, d. (2002b): depositional sequences and palaeogeography of the adriatic carbonate platform. – mem. soc. geol. it., 57, 141–151. vlahović, i., tišljar, j. & velić, i. (1994): influence of synsedimentary tectonics and eustatic changes on deposition of the cenomanian platform carbonates in istria (western croatia).– géologie méditerranéenne, 3–4, 189–193. vlahović, i., velić, i., tišljar, j. & matičec, d. (2001): utjecaj sinsedimentacijske tektonike na malmsku paleogeografiju jadranske karbonatne platforme (malmian palaeogeography of the adriatic carbonate platform as a consequence of the synsedimentary tectonics).– in: dragičević, i. & velić, i. (eds.): 1. znanstveni skup “karbonatna platforma ili karbonatne platforme dinarida” (1st scientific meeting “carbonate platform or carbonate platforms of dinarids”), knjiga sažetaka (abstracts), 51–54, zagreb. vlahović, i., korbar, t., moro, a., velić, i., skelton, p.w., fuček, l. & tišljar, j. (2002): latest cenomanian to earliest turonian platform drowning and turonian recovery of shallow-water platform deposition in southern istria.– in: vlahović, i. & korbar, t. (eds.): 6th international congress on rudists, rovinj, abstracts and excursion guidebook. 123–127, zagreb. vrhovčić, j., vujnović, l. & mojičević, m. (1983): osnovna geološka karta sfrj 1:100.000. list ključ, (basic geological map sfry 1:100.000, the ključ sheet). l 33–130.– geoinženjering sarajevo (1978), savezni geološki zavod beograd. vujisić, t. (1972): osnovna geološka karta sfrj 1:100.000. list nikšić (basic geological map sfry 1:100.000, the nikšić sheet), k 34–38.– zavod za geol. i geofiz. istraž. beograd (1967), savezni geološki zavod beograd. zappaterra, e. (1990): carbonate paleogeographic sequences of the periadriatic region.– boll. soc. geol. ital., 109, 5–20. zappaterra, e. (1994): source rock distribution model of the periadriatic region.– aapg bull., 78/3, 333–354. 184 geologia croatica 55/2 geo.cro.2-3-61-kb.pdf 379 � borna lužar-oberiter1, snježana mikulčić pavlaković2, marta crnjaković2 and ljubomir babić1 ab stra ct the composition of beach sands from the islands of rab and susak (northern adriatic) has been studied in order to determine how individual beaches are supplied with detritus. the beaches on both islands are composed of quartz dominated siliciclastic sand, with subordinate carbonate content. three end-member heavy mineral assemblages have been identifi ed among the studied beach sands, each one associated with a specifi c source rock: (1) a garnet dominated assemblage and (2) a zircon, rutile and tourmaline dominated assemblage on rab island, as well as (3) an assemblage dominated by unstable minerals on susak island. sands from individual beaches contain one of these specifi c assemblages or display a mixing of two varieties. the end-member assemblages are very comparable with those of eocene and pleistocene sediments which crop out on the two islands, identifying them as the principal sources of detritus. cretaceous and eocene carbonate rocks, although present to a considerable extent in the study area, have shown to be a negligible source of sandy material. thus, the supply of detritus to the beaches is primarily controlled by erosion of siliciclastic rocks in the immediate or nearby hinterland. keywor ds: beach sands, sediment supply, framework composition, heavy minerals, rab, susak, croatia 1 department of geology, faculty of science, university of zagreb, horvatovac 102a, 10000 zagreb, croatia; (bluzar@geol.pmf.hr) 2 croatian natural history museum, demetrova 1, 10000 zagreb, croatia variable sources of beach sands of north adriatic islands: examples from rab and susak geologia croatica 61/2–3 379–384 4 figs. 2 tabs. zagreb 2008 geologia croaticageologia croatica � 1. introduction analysis of framework composition and heavy mineral assemblages are commonly used tools for delineating provenance of both ancient and recent sediments (weltje & von eynatten, 2004; garzanti & ando, 2007). in particular, many studies have employed such methods to determine sources of detritus and reconstruct supply pathways by which coastal areas are supplied with sand (e.g. giles & pilkey, 1965; gandolfi et al., 1982; clemens & komar, 1988; potter, 1994; marchesini et al., 2000; sabeen et al., 2002; garzanti et al., 2002, 2003; cascalho & fradique, 2007). beaches represent a delicate coastal environment, one that is easily subject to destructive processes if an imbalance is created between the supply of detritus and erosion (komar, 1998). in the european union, comprehensive coastal investigations have shown that its coastal beach environments are experiencing increased erosion due to lack of sediment, attributed primarily to human activity (salman et al., 2004). given the rising pressure from development, the coastal environments of croatia can be expected to become more and more vulnerable to such processes in the future. a better understanding of how beaches are supplied with sandy material is crucial when considering the protection and management of such environments, which is essential if their aesthetic, recreational and economic values are to be preserved. with the above notions in mind, we have conducted a comparative beach sediment study on the islands of rab and susak, located in the kvarner region of the ne adriatic (fig. 1). to date our research on beach sands from rab island has shown that considerable variability exists in their heavy mineral compositions (babić et al., 1997; crnjaković et al., 1998; lužar-oberiter et al., 2005; lužar-oberiter, 2006). in the current study, data has been obtained from geologia croatica geologia croatica 61/2–3 380 both modern beach sands and ancient rocks from both islands, which we use to document the presence of three end-member heavy mineral assemblages and more precisely defi ne the relationships between individual beaches and their source(s) of sand (mikulčić pavlaković et al., 2006). 2. material and methods six separate beaches have been chosen from various bays on rab island, while for the smaller island of susak, the beach in bok bay has been selected as a representative location (fig. 1). samples of beach sands were taken from the foreshore of each beach (samples r1 to r6 and s1 to s3). to identify the sources from which the individual beaches are supplied with detritus, potential source rocks which crop out on the islands were identifi ed and sampled. these included eocene sandstones (samples er1 and er2) which are ubiquitous on rab island (fig. 1), as well as pleistocene sediments from both islands (samples pr1, pr2, ps1 to ps3). thin sections were produced from both hard rock and disaggregated sand samples. for disaggregated samples, which included beach and pleistocene sands, the material was fi rst artifi cially cemented with epoxy. thin sections were inspected under a polarizing light microscope to determine framework composition. all samples were treated with 3% hydrochloric acid to remove carbonates. rock samples were crushed prior to acid treatment, for which only fragments larger than 1mm were used. carbonate content was calculated from the weight difference before and after acid treatment. obtaining heavy mineral concentrates was performed by gravity separation with bromoform (mange & maurer, 1992), using the 0.05– 0.125 mm size fraction after sieving. heavy mineral proportions were determined by ribbon counting 300–400 grains in each sample. we have chosen to display these results as proportions of three groups of heavy mineral species, which have been determined to best express the differences between our studied samples: 1) garnet, 2) zircon, tourmaline and rutile (ztr), and 3) other transparent grains. 3. results 3.1. ancient rocks in the two eocene sandstone samples from rab island angular to subangular quartz predominates among the framework grains. the remainder of the siliciclastic component is made up mostly of rounded chert grains. feldspars, mica and other lithic fragments (pelitic, quartzite type, quartz-feldspar aggregates) also occur. the measured carbonate content in these two samples is 35% and 48%, (table 1) most of which is present in the form of matrix. the pleistocene sands of rab island are largely dominated by monocrystalline quartz grains, along with rarer chert, commonly with a limonitic coating. other lithic fragments are brown limonitized fi negrained clasts. feldspars are rare. unlike in the eocene sandstones carbonate is almost completely absent (1–4%), in these sands. fi gu re 1: maps of the study area with marked locations of the analyzed samples. basic lithologies are simplifi ed after mamužić (1962, 1968) and mamužić et al. (1969, 1973). geologia croaticaborna lužar-oberiter et al.: variable sources of beach sands of north adriatic islands: examples from rab and susak 381 the samples of pleistocene sand from susak island contain 16–34% carbonate (table 2) which is present as grains of micritic or microsparitic limestone. rare mosaic grains with large crystals or individual larger carbonate crystals were identifi ed as probable dolostones. the siliciclastic component is mostly quartz, along with lithic fragments, feldspars and mica. the lithic fragments are aggregates of mica and quartz, epidote or zoisite, or may be entirely composed of sericite. micro-quartzite and chert fragments are much rarer. heavy mineral assemblages from the analyzed rock types which crop out on the two islands demonstrate obvious dissimilarities (tables 1 and 2). eocene sandstones from rab island are characterized by the dominance of garnet and a low proportion of ztr (66% and 11% in average, respectively). the analyzed pleistocene sands from rab island have a much lower garnet content together with a high proportion of ztr (5% and 63% in average, respectively). the pleistocene sands of susak island demonstrate yet a third compositional type with low garnet and low ztr content (17% and 4% in average, respectively), while the bulk of the heavy mineral fraction is made up of unstable minerals, mostly amphiboles and epidote/zoisite. 3.2. beach sands all the beach sands analyzed from rab island are predominantly composed of siliciclastic material, and contain only a small amount of carbonate. those from the kalifront peninsula (samples r1, r2, r3; fig.1) are clearly dominated by quartz, along with rarer chert grains. lithic fragments of weathered quartz sandstone occur occasionally. feldspar is almost completely absent. carbonate grains do occur (6–9% carbonate), but these are primarily shell fragments of recent organisms. only rarely are they detrital carbonate grains of a somewhat larger grain size than the siliciclastic material. on the lopar peninsula (samples r5 and r6), quartz also dominates the beach sands. lithic fragments are fairly common and are mostly chert grains, along with occasional fragments of eocene sandstone. other rarer fragments are quartzite types, phylitic or quartz-feldspar aggregates. carbonate grains are rare (4–9% carbonate), and consist of recent shell fragments and redeposited foraminifera (nummulites) from the eocene sandstones. sample r4 (fig. 1) is comparable in framework composition to samples r5 and r6 described above. the siliciclastic component in the beach sands from bok bay on susak island is almost identical to that of the pleistocene sand present on the island. only the amount of mica varies signifi cantly due to hydraulic sorting. the carbonate content in two of the beach sand samples is similar (26% and 28%) to that of the pleistocene sands. however, the third sample contains a considerably higher proportion of carbonate (66%). this excess carbonate comes from shell fragments of recent organisms, mostly foraminifera. heavy mineral assemblages of various beach sands from the two studied islands show major differences. in the beach sands from rab island, the variations in the proportion of garnet relative to ztr are most conspicuous. among the individual beaches of rab island, the garnet content varies between 12% and 72%, while the ztr vary from 11% to 67% (table 1). a higher proportion of garnet relates to a lower proportion of ultrastable minerals, and vice versa. among the other heavy minerals encountered are epidote/zoisite, cr-spinel, pyroxenes, staurolite and kyanite, the proportions of which do not differ signifi cantly among the studied samples. unlike those of rab island, the beach sands from susak island demonstrate relatively low amounts of garnet and ztr (12–26% and 4–5%, respectively), and instead contain a very high proportion of unstable minerals, mainly amphiboles and epidote (table 2). 4. discussion analysis of thin sections reveals a strongly dominating siliciclastic component in the composition of the studied beaches on rab island. although cretaceous and eocene carbonate rocks cover a large area of the island, they obviously play a negligible role in supplying sandy material to the studied coastal areas. indeed, the carbonate material that is present in the sands is more commonly composed of recent shell fragments or redeposited foraminifera than detrital carbonate grains. even most of the carbonate which makes up a considertable 1: carbonate content and proportions of specifi c heavy mineral groups in samples of beach sands (r1–r6), eocene sandstones (er1, er2) and pleistocene sands (pr1, pr2) from rab island. ztr = zircon+tourmaline +rutile; ot = other transparent heavy mineral grains. sample locality % caco3 % ztr % garnet % ot r1 planka 9 67 13 20 r2 vardarika 6 62 12 26 r3 valafta 9 52 18 30 r4 gonar 4 34 41 25 r5 crnika 4 32 42 26 r6 saramić 9 11 72 17 er1 lopar 35 13 72 15 er2 palit 48 9 60 31 pr1 kalifront 4 63 6 31 pr2 fruga 1 62 4 33 table 2: carbonate content and proportions of specifi c heavy mineral groups in samples of beach sands (s1–s3) and pleistocene sediments (ps1–ps3) from susak island. ztr = zircon+tourmaline+rutile; ot = other transparent heavy mineral grains. sample locality % caco3 % ztr % garnet % ot s1 bok 28 3 15 83 s2 bok 66 5 25 70 s3 bok 26 2 10 88 ps1 bok 22 4 12 84 ps2 bok 16 5 26 69 ps3 bok 34 4 13 83 geologia croatica geologia croatica 61/2–3 382 able proportion of the eocene sandstones, (up to 48%), does not arrive on the beaches which contain a maximum of 9% carbonate. this is probably because most of it is present as matrix in the sandstones, and is lost during weathering. furthermore, this also excludes coarse grained quaternary sediments, (holocene after mamužić et al., 1973), common on the se part of the island as a source of material for the beaches included in this study, as they contain predominantly detrital carbonate fragments. instead, eocene sandstones and pleistocene quartz sands are the obvious dominant sources of detritus, which is refl ected in the general similarity between their framework components and the grain composition of the beach sands. lithic fragments identifi ed in some of the beach samples, are an additional indicator of these source rocks. the general similarity in the dominant framework components between the eocene and pleistocene source rocks on rab island does not allow for a more precise evaluation of the contribution each of these sources makes to a specifi c beach. in this regard, a comparison of heavy mineral assemblages showed to be a much better indicator. the consistent variability in the garnet versus ztr proportions in heavy mineral assemblages of the studied beaches indicates the derivation of these sands. while the garnet-rich and ztr-poor beach sands (lopar peninsula), closely resemble those of eocene sandstones, the beach sands rich in ztr and poor in garnet (kalifront peninsula) are comparable to those of pleistocene sands (fig. 2). these relationships suggest that some beaches are supplied exclusively from eocene rocks (e.g. saramić – r6), some from pleistocene sands (e.g. planka – r1), while other beaches receive detritus from both sources (e.g. gonar – r4 and crnika – r5). this is consistent with the previously proposed view on the provenance of the rab beach sands which was based on the study of only three beach samples (crnjaković et al., 1998), and a similar conclusion has been reached for the northern dalmatian coast (pavičić et al., 2000), where analogous rocks were identifi ed as important sources of detritus for beach sands. the beach sands from susak island show almost identical compositions to those of the analyzed pleistocene sands on this island, both in framework components and heavy minerals (fig. 3). such a conspicuous similarity results from the large coverage of pleistocene sand (fig. 1) which is characterized by a homogenous composition throughout the island (mutić, 1967; bognar et al., 1983; cremaschi, 1990; mikulčić pavlaković, 2006). furthermore, considering that the carbonate content in the beach sand has been attributed to shells of recent organisms, the carbonate rocks on susak island represent a negligible source of sandy material to bok bay. the heavy mineral assemblages of the susak beach sands are considerably different from those of rab island (tables 1 and 2). consequently, we have identifi ed three end-member heavy mineral assemblages in the beach sands of the two islands: 1) garnet dominated assemblage from rab island, 2) ztr dominated assemblage from rab island and 3) assemblage dominated by unstable minerals from susak island. these correspond to the heavy mineral assemblages of the three studied ancient rock types from the two islands: 1) eocene sandstones, 2) pleistocene sands of rab island and 3) pleistocene sands of susak island, respectively (fig. 4). consequently, we have shown that studying the heavy mineral assemblage of beach sand allows the assessment of the contribution each source rock makes to a specifi c beach. the substantial variability of beach sand compositions detected across a relatively short distance of shoreline, as witnessed on rab island, allows us to conclude that the supply of detritus to the beaches must be primarily controlled by erosion of siliciclastic sediments in the immediate or nearby hinterland. other possible supply paths such as longshore transport or a derivation from a more distant source are obviously less signifi cant in this area. in the bottom sediments surrounding rab island, škrivanić & magdalenić (1979) determined sand dominated by quartz along with heavy mineral assemblages with fi gu re 2: a comparison in the proportions of ztr, garnet and other transparent grains among diff erent beach sands from rab island (r1–r6). results from a pleistocene sand sample (pr1) and an eocene sandstone sample (er1) are added for additional comparison. ztr=zircon+tourmaline+rutile; ot=other transparent grains. geologia croaticaborna lužar-oberiter et al.: variable sources of beach sands of north adriatic islands: examples from rab and susak 383 increased amounts of zircon and garnet, which is similar to the framework composition and dominant heavy minerals we detected in the studied beaches on the island. this suggests that the supply of sand material from eocene sandstones and pleistocene sands probably extends to the bottom sediments of the surrounding seaways. similarly, heavy mineral assemblages analogous to those of the pleistocene sands on susak island can be found in the bottom sediments of the northern adriatic (pigorini, 1968), including the western part of the kvarner region (škrivanić & magdalenić, 1979). the source areas and the natural transport directions of beach sands from the islands of rab and susak have been successfully assessed using framework composition and heavy mineral assemblages. since haphazard construction can potentially cut off vital sediment supply paths and disrupt the beach sediment budget, which eventually leads to sediment defi cit and coastal erosion, we propose that the information derived from this and other similar coastal studies should be taken into account when planning future development along the relevant coastline. in our continuing research we are extending our study area to embrace a greater coverage of the croatian coastline, including other islands as well as the mainland. 5. conclusions this study has shown that the studied beach sands of the islands of rab and susak are made up primarily of siliciclastic, quartz dominated detritus. carbonate particles are mostly a minor component. three end-member heavy mineral assemblag es, each related to a different source rock, have been identifi ed in the studied beaches: 1) a garnet dominated assemblage and 2) a zircon, rutile and tourmaline dominated assemblage on rab island, as well as 3) an assemblage dominated by unstable minerals on susak island. intermediate compositional types of beach sands result from the mixing of detritus supplied from two sources. consequently, erosion of siliciclastic sediments in the immediate or nearby hinterland, specifi cally eocene sandstones and two varieties of pleistocene sands, has a primary role in providing the studied beaches with sandy material, while longshore transport or derivation from a distant source are much less signifi cant. meanwhile, the carbonate, where present, is more commonly derived from shells of recent organism’s than from eroding cretaceous and eocene carbonate rocks. furthermore, for the studied area, the heavy mineral assemblage of sand from a specifi c beach allows the successful identifi cation of its specifi c source rock(s). we propose that the conclusions derived from this study should be taken into account when planning future development of the relevant coastline. acknowledgment this work was funded the croatian ministry of science, education and sports project 119-1191155-1159 “evolutionary changes of the dinarides from subduction to modern adriatic beaches”. we would like to thank dr. giovanni vezzoli and dr. dunja aljinović for their critical reviews of the manuscript and their constructive suggestions which signifi cantly improved the fi nal version. references babić, lj., crnjaković, m. & zupanič, j. (1997): complex nourishment of sand beaches of the island of rab (eastern adriatic, croatia). – meeting on environmental sedimentology, ias-sepm, venice, abstracts, w3s–26. fi gu re 3: a comparison of the proportions of ztr, garnet and other transparent grains among diff erent beach samples from susak island (s1–s3). results from a pleistocene sand sample from susak island (ps1) are added for additional comparison. see legend in fig. 2. fi gu re 4: a comparison of the average ztr, garnet and other transparent mineral proportions among the three diff erent source types. see legend in fig. 2. geologia croatica geologia croatica 61/2–3 384 bognar, a., klein, v., tončić-gregl, r., šercelj, a., magdalenić, z. & culiberg, m. (1983): kvartarne naslage otoka suska i baške na otoku krku i njihovo geomorfološko značenje u tumačenju morfološke evolucije kvarnerskog prostora [quaternary layers of the island of susak and baška on the krk island and its importance for the interpretation of the geomorphological development of the kvarner region – in croatian, english summary]. – geogr. glasnik, 45, 7–32. cascalho, j. & fradique, c. (2007): the sources and hydraulic sorting of heavy minerals on the northern portuguese continental margin. – in: mange, m.a. & wright, d.t. (eds.): heavy minerals in use. developments in sedimentology, 58. elsevier, amsterdam, 75–110. clemens, k.e. & komar, p.d. (1988): oregon beach-sand compositions produced by the mixing of sediments under a transgressing sea. – j. sediment. petrol., 58, 519–529. cremaschi, m. (1990): stratigraphy and palaeoenviromental significance of the loess deposits on susak island (dalmatian archipelago). – quat. int., 5, 97–106. crnjaković, m., babić, lj., & zupanič, j. (1998): održivost plaža hrvatske obale jadrana: sediment kao glavni faktor [sustainability of beaches of the croatian adraitc coast: a sediment source perspective – in croatian, english abstract]. – in: arko-pijevac, m., kovačić, m. & crnković, d. (eds.): natural history researches of the rijeka region 1. natural history museum rijeka, rijeka, 339–344. gandolfi, g., mordenti, a. & paganelli, l. (1982): composition and longshore dispersal of sands from the po and adige rivers since the pre-etruscan age. – j. sediment. petrol., 52, 797–805. garzanti, e. & ando, s. (2007): heavy mineral concentrations in modern sands: implications for provenance interpretation. – in: mange, m.a. & wright, d.t. (eds.): heavy minerals in use. developments in sedimentology, 58. elsevier, amsterdam, 517– 545. garzanti, e., ando, s., vezzoli, g. & dell’era, d. (2003): from rifted margins to foreland basins: investigating provenance and sediment dispersal across desert arabia (oman, u.a.e.). – j. sediment. res., 73, 572–588. garzanti, e., canclini, s., moretti foggia, f. & petrella, n. (2002): unraveling magmatic and orogenic provenance in modern sand: the back-arc side of the apennine thrust belt, italy. – j. sediment. res., 72, 2–17. giles, r.t. & pilkey, o.h. (1965): atlantic beach and dune sediments of the southern united states. – j. sediment. petrol., 35, 900–910. komar, p.d. (1998): beach processes and sedimentation, 2nd edition. – prentice hall, upper saddle river, 544 p. lužar-oberiter, b. (2006): usporedba sastava i porijekla obalnih pijesaka otoka hvara i raba [comparison of the composition and sources of coastal sands from the islands of hvar and rab – in croatian, english abstract]. – unpublished masters thesis, university of zagreb, 85 p. lužar-oberiter, b., crnjaković, m., babić, lj. & zupanič, j. (2005): provenance of beach sands from the island of rab: evidence from heavy minerals. – in: velić, i., vlahović, i. & biondić, r. (eds.): 3rd croatian geological congress, opatija abstract book. croatian geological survey, zagreb, 91–92. mamužić, p. (1962): novija geološka istraživanja otoka raba [neuere geologische untersuchungen der insel rab – in croatian, german summary]. – geol. vjesnik, 15, 121–141. mamužić, p. (1968): osnovna geološka karta sfrj 1:100000, list lošinj [basic geological map of sfry 1:100000, lošinj sheet]. – institute of geology, zagreb, federal geol. inst., belgrade. mamužić, p., milan, a., korolija, b., borović, i. & majcen, ž. (1969): osnovna geološka karta sfrj 1:100000, list rab [basic geological map of sfry 1:100000, rab sheet]. – institute of geology, zagreb, federal geol. inst., belgrade. mamužić, p., milan, a., korolija, b., borović, i. & majcen, ž. (1973): osnovna geološka karta sfrj 1:100.000. tumač za list rab [basic geological map 1:100.000, rab sheet – in croatian]. – institute of geology, zagreb, federal geol. inst., belgrade. mange, m. & maurer, f. (1992): heavy minerals in colour. – chapman & hall, london, 147 p. marchesini, l., amorosi, a., cibin, u., zuffa, g.g., spadafora, e. & preti, d. (2000): sand composition and sedimentary evolution of a late quaternary depositional sequence, northeastern adriatic coast, italy. – j. sediment. res., 70, 829–838. mikulčić pavlaković, s. (2006): mineraloške karakteristike pijesaka i piroklastita otoka suska [mineralogical characteristics of sands and pyroclastics of the susak island – in croatian, english abstract]. – unpublished masters thesis, university of zagreb, 126 p. mikulčić pavlaković, s., crnjaković, m., lužar-oberiter, b. & babić, lj. (2006): the variable origin of beaches of north adriatic islands – does coastal zone management require a separate approach for individual beaches? – in: arko-pijevac, m., kružić, b. & kovačić, m. (eds.): abstracts. – natural history researches of the rijeka region 2. natural history museum rijeka, p. 111. mutić, r. (1967): pijesak otoka suska: struktura, sastav i uvjeti sedimentacije [the sand of the island of susak: structure, composition, and conditions of deposition – in croatian, english summary]. – geol. vjesnik, 20, 41–56. pavičić, lj., babić, lj., crnjaković, m., & zupanič, j. (2000): the provenance of sands on north dalmatian beaches: between ignorance and the need for coastal zone management. – period. biol., 102, 349–354. pigorini, b. (1968): sources and dispersion of recent sediments of the adriatic sea. – marine geol., 6, 187–229. potter, p.e. (1994): modern sands of south america: composition, provenance and global signifi cance. – geol. rundsch., 83, 212–232. sabeen, h.m., ramanujam, n. & morton, a.c. (2002): the provenance of garnet: constraints provided by studies of coastal sediments from southern india. – sediment. geol., 152, 279–287. salman, a., lombardo, s. & doody, p. (2004): major fi ndings and policy recommendations of the eurosion project. – in: living with coastal erosion in europe: sediment and space for sustainability. service contract b4-3301/2001/329175/mar/b3, european commission, www.eurosion.org. škrivanić, a. & magdalenić, z. (1979): cruises of the research vessel “vila velebita” in the kvarner region of the adriatic sea: ix quaternary sea-bottom sediments. – thalassia jugoslavica, 15, 149–166. weltje, g.j. & von eynatten, h. (2004): quantitative provenance analysis of sediments: review and outlook. – sediment. geol., 171, 1–11. manuscript received february 13, 2008 revised manuscript accepted april 30, 2008 1. introduction few conodont data have previously been published from palaeozoic rocks of turkey but recent investigations have shown that palaeozoic conodonts are very common in turkey and provide very important new data for the stratigraphy, palaeogeography and tectonic evolution of turkey (e.g., kozur, 1997a, b, 1998; g ö n c ü oğlu & kozur, 1998a, b). no conodonts have previously been reported from the bolkardağ unit of the tauride-anatolide composite terrane, but gönc ü oğlu & kozur (1998a, b) dated a deep-sea turbidite-olistostrome unit within the bolkardağ unit (formerly assumed to be a variscan lower carboniferous sequence özcan et al., 1990) as late silurian to earliest devonian from conodont and muellerisphaerid evidence. the development of the carboniferous in the bolkar d ağ unit is not yet clear. özcan et al. (1990) reported a carboniferous deep-water sequence (variscan conodonts of middle moscovian age from the kongul formation (bolkardağ unit), northwest of hadim, central taurus, turkey erkan ekmekçi 1 and heinz w. kozur 2 development), but re-study of all known localities of this “variscan” flysch by göncüoğlu & kozur (1998a, b) did not confirm a variscan age for these rocks (see above). özgül (1997) assumed a middle devonian to viséan-serpukhovian age for the hocalar and lower kongul formations, and a bashkirian to moscovian age for the upper kongul formation, with no unconformity in the shallow-water deposits of this middle devonian to moscovian time interval. this would exclude the existence of any variscan oceanic unit and of variscan movements. shallow-water pre-permian deposits of the bolkard ağ unit from the hadim-bozkir area in the central taurides have been studied here, and pennsylvanian (moscovian) conodonts were discovered. as beds of this age could be either a shallow-water molasse (after the closure of a variscan ocean) or shallow-water platform carbonates in an area without variscan orogeny, further investigations of the underlying deposits (hocalar formation, fig. 2) are necessary. 2. geological setting and previous work the first detailed research on the geology of the central taurus was carried out by blumenthal (1944, 1956), who recognized the presence of permocarboniferous or permian limestone and of devonian(?) schists in the hadim region, and defined in 1956 a tectonic unit for palaeozoic rocks that was later named the bolkardağ unit. comprehensive studies of this region were undertaken by özgül (1969, 1976, 1984, 1997), özgül & gedik (1973), gedik (1977) and monod (1977). özgül (1984) subdivided the taurus belt into six main tectonic units, the geyikdağ autochthon and the antalya, alanya, aladağ, bolkardağ and bozkir units in nappe position. the bolkardağ unit is, according to özgül (1984), a rootless nappe over the lutetian flysch of the geyikdağ unit. it was subdivided by özgül (1997) into seven formations that range from the middle devonian to upper cretaceous. according to özgül (1984), the middle devonian to pre-turonian cretaceous rocks are shallow-water deposits, and deep-water conditions started in the turonian. g eol. c roa t. 52/1 1 8 3 figs. 1 pl. zagreb 1999 key words: conodonts, kongul formation, bolkardağ unit, atokan, moscovian, taurus, turkey. 1 maden tetkik ve arama, genel müdürlüğü, jeoloji etüdleri dairesi, eskişehir yolu, 06520 ankara, turkey 2 rézsü u. 83, h-1029 budapest, hungary. abstract a rich shallow water conodont fauna with i d i o g n a t h o d u s i n c u r v u s d u n n , i . cf. s u b e r e c t u s ( d u n n), idioprioniodus sp., and n e o gnathodus columbiensis stibane was found in the lower part of the kongul formation of the bolkardağ unit, about 12 km nw of hadim town, central taurus, turkey. the conodonts indicate a middle to late atokan age (on the american scale) for this part of the formation. on the russian scale, the fauna corresponds to the middle moscovian. according to previous correlations between the russian and north american scales, a (middle) late atokan (middle moscovian age) is assumed for this fauna. variscan deep-water sequences are not present in the study area. 2 geologia croatica 52/1 the carboniferous of the bolkardağ unit is represented by the kongul formation which was subdivided by ozgül (1997) into the zindancik member of presumed viséan-serpukhovian age and the mantarbeleni member of presumed bashkirian to moscovian age. according to özgül (1997), the zidancik member concordantly overlies the presumed middle to upper devonian hocalar formation despite the fact that he could not date any tournaisian rocks. the zidancik member consists mainly of dark shales, sandstones and limestones, while the mantarbeleni member consists of shallow-water, partly oolitic or dolomitic limestones. in the study area, the kongul formation lies unconformably on the hocalar formation, and begins with middle moscovian limestones and shales, overlain by recrystallized limestone. a new tectonic view to the bolkardağ unit was presented by özcan et al. (1990). they assigned a siliciclastic deep-water flysch to the lower carboniferous assuming a variscan orogeny. subsequently, göncüoğlu & kozur (1998a, b) re-investigated three outcrops of these siliciclastic deep-sea flysch sequences and underlying ribbon cherts. in two sections, limestone and lydite olistoliths from the turbidite-olistostrome unit yielded upper silurian to pragian conodonts. in a third outcrop, black ribbon cherts from a distal turbiditic shale-chert sequence with several benthonitic layers (altered felsic to intermediate tuffs) yielded wenlock to upper silurian muellerisphaerida. from these results, the existence of a caledonian-time oceanic sequence was proven. this karaburun-bolkardağ ocean (kozur, 1997a, b, 1998) separated for example, ordovician baltic warm-water faunas with connections to siberian and north american warm-water faunas, from a typical perigondwana ordovician cold-water association (dean & martin, 1992; martin, 1996; göncüoğa b fig. 1 geological map. a) generalized geological map of the hadim-bozkir area. legend: a) postmesozoic cover rocks; b) dipsizgöl ophiolite; c) bozkir unit; d) bolkardağ unit; e) aladağ unit (hadim unit); f) geyikdağ autochthon (anamas-akseki autochthon); g) hadim overthrust; h) b o l k a r d ağ overthrust; i) bozkir overthrust; j) ophiolite overthrust; k) normal contact; l) study area. b) geological map of the study area and sample location. legend: a) palaeogene of the anamas-akseki autochthon; b) cretaceous siliciclastic sediments and volcanic rocks (polat fm.) of the aladağ unit; c-f) bolkardağ unit: c) pre-moskovian hocalar fm., d) moscovian kongul fm., e) permian kinikyayla fm., f) triassic ekinlikyayla fm; g) bolk a r d ağ unit overthrust; h) polat fm. overthrust; i) normal contact; j) dip-strike; k) drainage system; l) sample location; m) stabilized road. modified after ozgül (1969). 3ekmekçi & kozur: conodonts of middle moscovian age from the kongul formation (bolkardağ unit)... fig. 2 generalized columnar section of the bolkardağ unit (hocalar to söğüt formations) in the study area (after özgül, 1997). 4 geologia croatica 52/1 lu & kozur, 1998a, b). as in the karaburun zone both upper silurian-pragian and upper famennian to middle viséan oceanic sequences are present, this may be also assumed for the bolkardağ unit, although the triassic in this unit indicates a somewhat more southern palaeogeographic location than that for the triassic of the karaburun zone. however, until now no variscan deep-sea sequence was found in the bolkardağ unit. 3. locality data the conodont-bearing sample from the lower part of the kongul formation (bolkardağ unit) was obtained from a road cut 2 km southeast of kiremez village, about 12 km nw of hadim (fig. 1). the exposed carboniferous kongul formation consists of recrystallized limestone, black, thin-bedded cherty limestone, reddish shale and black, thinto medium-, partly thick-bedded fossiliferous limestone. the conodonts were obtained from sample al 95/740 l that was taken from a fossiliferous limestone in the lower part of the kongul formation at this locality (fig. 2). 4. age of the conodont fauna from the lower kongul formation the following conodonts were determined from sample al 95/740 l: i d i o g n a t h o d u s i n c u r v u s d u n n , 1966, i. ? cf. suberectus (dunn, 1966), idioprioniodus sp., and neognathodus columbiensis (stibane, 1967). within the idiognathodid plexus i . s i n u o s u s e l l ison & graves i . i n c u r v u s dunn i . o b l i q u u s kosenko & kositskaya forms with an inwardly curved and deflected downward posterior platform, continuous and equally spaced transverse ridges on the platform, a better developed and ornamented inner platform lobe and a well developed and flared inner serrate adcarinal ridge, as in our i . i n c u r v u s material, are, according to dr. r.g. stamm, reston, and dr. b.r. wardlaw, reston (pers. comm.), most typical of middle and late atokan age. such forms also occur in the late early and middle moscovian of russia. a similar age is indicated by n . c o l u m b i e n s i s that occurs in the middle to late atokan and in the moscovian, except the latest moscovian. a similar i d i o g n a t h o d u s fauna and n . c o l u m b i e n s i s is also present in the middle moscovian of the bükk mts. in northern hungary (kozur, 1984). only the presence of idiognathodus ? cf. suberectus is problematical for age determination. this species was previously classified as s t r e p t o g n a t h o d u s. however, it lacks a true platform trough and the anterior platform lobes are not reduced to absent as characteristic of true streptognathodids. thus, this species is more closely related to i d i o g n a t h o d u s than to s t r e p t o g n a t h o d u s. however, the missing uninterrupted transverse ribs in most of the platform makes this species an atypical idiognathodus. it may represent a new genus. this species was previously described from the middle morrovian (dunn, 1966) which corresponds to the lower bashkirian, an age that strongly conflicts with the age given by the common i . i n c u r v u s of the above mentioned morphotype and n . c o l u m b i e n s i s. however, according to dr. r.g. stamm and dr. b.r. wardlaw (pers. comm.), i . ? s u b e r e c t u s is also known to occur sporadically through the late morrowan and atokan. this fits well with our material, in which i . ? cf. s u b e r e c t u s is very rare, whereas i . i n c u r v u s and n . c o l u m b i e n s i s are common. i d i o p r i o n i o d u s sp. gives no age, but is indicative of shallow-water conditions. 5. conclusions the kongul formation in the study area unconformably overlies the hocalar formation. the age of the lower kongul formation in the study area is middle to late atokan on the north american scale and late early moscovian to middle moscovian in the international (russian) scale. this corresponds to the upper duckmantian to earliest westfalian d of the western european scale (fig. 3). tethyan conodonts of this age were previously described from the bükk mountains of hungary (kozur, 1984) where they represent the oldest shallow-water deposits above lower carboniferous to bashkirian flyschoid deposits. neither variscan deep-water sediments (öczan et al., 1990) nor lower carboniferous shallow-water deposits (özgül, 1997) were found in the bolkardağ unit of the study area. thevariscan orogeny cannot be proven in the study area. the presence of a silurian to lower devonian oceanic sequence (known from other parts of the bolkardağ zone göncüoğlu & kozur, 1998a, b) can neither be proven nor excluded for the bolkardağ unit of the study area, because the lower thrust boundary of the b o l k a r d ağ unit is not older than middle devonian (özgül, 1997). acknowledgments the authors express their thanks to a tübitak nato cp grant and the general directorate of mineral research and exploration who have kindly supported the field work. dr. e.m. öztürk and the members of the central taurus project are acknowledged for their discussions and contributions in the field. we especially thank dr. r.g. stamm and dr. b.r. wardlaw, reston, for important help in determination of the fauna and above all for giving us the exact range of the species within the north american scale. we thank also prof. dr. t. nemirovskaya, kiev, for a discussion of the age of the conodonts. we thank very much prof. c.m. göncüoğlu, ankara, prof. dr. h. mostler, 5ekmekçi & kozur: conodonts of middle moscovian age from the kongul formation (bolkardağ unit)... innsbruck, and prof. dr. a. ramov©, ljubljana, for revising and improving the manuscript. we are also very grateful to dr. julie robson, southminster, for her language editing and very useful comments. 6. references blumenthal, m. (1944): schichtenfolge und bau der taurusketten im hinterland von bozkir.rev. fak. sci. univ. istanbul, b 9/2, 15-125, istanbul. blumenthal, m., (1956): yüksek bolkardaği n i n kuzey kenar bölgelerinin ve bati uzantilarinin jeo l o j i s i (the geology of the northern border of the high bolkardağ and western extensions). m t a yayy’n seri d, 7, ankara. dean, w.t. & martin, f. (1992): ordovician biostratigraphic correlation in southern turkey.in: webby, b.d. & laurie, j.r. (eds.): global perspectives on ordovician geology. 195-203. dunn, d.l. (1966): new pennsylvanian platform config. 3 correlation of the carboniferous standard subdivision with the western european and north american subdivisions (after kozur, 1984, and wagner & winkler prins, 1997). vertical distances not time-related. p = permian. 6 geologia croatica 52/1 odonts from southwestern united states.j. paleont., 40/6, 1294-1303. gedik, i. (1977): conodont biostratigraphy in the middle taurus.bull. geol. soc. turkey, 20, 35-48, ankara. göncüoğlu, c. & kozur, h. (1998a): remarks to the pre-variscan development in turkey.in: linnemann, u., heuse, t., fatka, o., kraft, p., brocke, r. & erdtmann, b.-d. (eds.): pre-variscan terrane analysis of “gondwanan europe”. schr. staatl. mus. min. geol. dresden, 9, 137138, dresden. göncüoğlu, c. & kozur, h. (1998b): facial development and thermal alteration of the silurian of turkey and its importance for the reconstruction of the hercynian and pre-hercynian development in turkey.in: gutierez-marco, j.c. & rabano, i. (eds.): proceedings of the 1998 field meeting, iugs subcommission on silurian stratigraphy. temas geologico-mineros itge, 23, 87-90, madrid. kozur, h. (1984): biostratigraphic evaluation of the upper paleozoic conodonts, ostracods and holothurian sclerites of the bükk mts. part i: carboniferous conodonts and holothurian sclerites.acta geol. hungar., 27/1-2, 143-162. kozur, h. (1997a): new stratigraphic results on the paleozoic of the western parts of the karaburun peninsula, western turkey.in: pişkin, ö., ergün, m., savaşçin, m.y. & tarcan, g. (eds.): proc. international earth sciences colloquium on the aegean region, iesca 1995, 1, 289-307, izmir. kozur, h. (1997b): first discovery of muellerisphaerida (inc. sedis) and e o a l b a i l l e l l a (radiolaria) in turkey and the age of the siliciclastic sequence (clastic series) in karaburun peninsula.freiberger forsch.-h., c 466, 33-59. kozur, h. (1998): the age of the siliciclastic series (“karareis formation”) of the western karaburun peninsula, western turkey.in: szaniawski, h. (ed.): proc. sixth european conodont symposium (ecos vi). palaeont. polonica, 58, 169-187, warszawa. martin, f. (1996): recognition of the acrtarch-based “t r i f i d u m flora” (ordovician) in the absence of the eponymous species.bull. inst. royal. sci. natur. belgique, 66, 5-13, bruxelles. monod, o. (1977): recherces geologiques dans la taurus occidentales au sud de beyşehir (turquie).unpublished phd thesis, univ. sud orsay, 442 p., paris. plate i all illustrated specimens are from sample al 95/740 l, lower kongul formation, middle moscovian, bolkardağ unit, road cut 2 km southeast of kiremez village, about 12 km nw of hadim (for location see fig. 1 in the text). 1-8 idiognathodus incurvus dunn, upper view; fig. 1: x70, rep.-no. 23-2-97/iii-7; fig. 2: subadult specimen, x80, rep.-no. 23-2-97/iii-1; fig. 3: x80, rep.-no. 23-2-97/iii-2; fig. 4: late juvenile specimen, x80, rep.-no. 23-2-97/iii-5; fig. 5: x100, rep.-no. 23-2-97/iii-3; fig. 6: juvenile specimen, x80; rep.-no. 23-297/iii-4; fig. 7: late juvenile specimen, x80, rep.-no. 23-2-97/iii-8; fig. 8: x80, rep.-no. 23-2-97/iii-12. 9 and 12 i d i o g n a t h o d u s ? cf. s u b e r e c t u s (dunn), upper view; fig. 9: juvenile specimen, x100, rep.-no. 23-297/iii-16; fig. 12: x80, rep.-no. 23-2-97/iii-9. 10 and 11 neognathodus columbiensis (stibane), upper view; fig. 10: juvenile specimen, x100, rep.-no. 23-297/iii-10; fig. 11: broken specimen, x100, rep.-no. 23-2-97/iii-15. 13 idioprioniodus sp., broken lateral process, x80, rep.-no. 23-2-97/iii-6. 7ekmekçi & kozur plate i 8 geologia croatica 52/1 özcan, a., göncüoğlu, m.c., turhan, n., uysal, ş., şentürk, k. & işik, a. (1990): late paleozoic evolution of the kütahya-bolkardağ belt.metu journal of pure and applied sciences, series a geoscience, i, 21/1-3, 211-220, ankara. özgül, n. (1969): 1/25.000 scale geological map of n29c3-c4.archive of geological research departments, general directorate of mineral research and exploration (mta) (unpublished). özgül, n. (1976): toroslarin bazi temel jeolojik özellikleri (some geological aspects of the taurus orogenic belt (turkey)).bull. geol. soc. of turkey, 19, 65-78, ankara. özgül, n. (1984): geology of the central taurides.in: tekeli, o. & göncüoğlu, m.c. (eds.): geology of taurus belt. int. symposium, 26-29 september 1983, 77-90, ankara. özgül, n. (1997): bozkir-hadim-taskent (orta toroslar’in kuzey kesimi) dolayinda yer alan tektonostratigrafik birliklerin stratigrafisi.mta der., 119, 113-174, ankara. özgül, n. & gedik, i. (1973): orta toroslarda alt paleozoyik yaşta çaltepe kireç t aşi ve seydişe h i r formasyonunun stratigrafisi ve konodont faunasi hakkinda yeni bilgiler.bull. geol. soc. turkey, 16, 39-52, ankara. stibane, f.r. (1967): conodonten des karbons aus den nördlichen anden südamerikas.n. jb. geol. paläont., abh., 128, 329-340, stuttgart. wagner, r.h. & winkler prins, c.f. (1997): carboniferous chronostratigraphy: quo vadis?in: podemski, m., dybova-jachowicz, s., jaw o r o w s k i, k., j u r e c z k a, k. & w a g n e r, r. (eds.): proceedings of the xiii international congress on the carboniferous and permian. prace pánstw. inst. geol., 157, 145-157, warszawa. manuscript received july 29, 1998. revised manuscript accepted may 28, 1999. tibljas et al.indd 1. introduction turonian to upper santonian limestones rich in rudist remains crop out in the southernmost part of istria, at the mrlera and premantura peninsulas (fig. 1). according to the latest stratigraphic and palaeoenvironmental investigations of the rudists from these rocks (moro, 1997; moro & ćosović, 2000) specimens of the genera durania, praeradiolites and radiolites thrived in the shallower parts of the subtidal zone in an inner shelf environment, while specimens of the genera gorjanovicia and vaccinites lived in the deeper subtidal environment with pelagic influxes (outer shelf). the main aim here was to determine the mineral (i.e. phase) and chemical composition of the valves of several rudist genera from pure carbonates without the mineral and chemical composition of rudist valves from upper cretaceous limestones of southern istria, croatia darko tibljaš1, alan moro2 and željka ostrež3 influence of terrigenous material, and to explain any observed differences. 2. materials and methods during the study, 22 samples of rudist valves (five of the genus durania, samples d1–d5; four of the genus gorjanovicia, g1–g4; four of the genus praeradiolites, p1–p4; five of the genus radiolites, r1–r5, and four of the genus vaccinites, v1–v4) were analysed. according to the biostratigraphy, the rudist genera durania, radiolites and praeradiolites lived during the middle to upper turonian, gorjanovicia lived in the time span from upper turonian to santonian while vaccinites specimens are of santonian age (moro, 1997; moro & ćosović, 2000). zonation of shells was absent in observed hand specimens, so complete shell material, comprising the outer and inner layers, was taken for analysis. microand macro-photographs of some analysed rudists from the investigated area are given in polšak (1967b – plates 18–21, 69, 70) and moro (1997 – plate 1: figs. 1, 2, 3, 5 & 6; plate 2: figs. 1 & 3). the mineral composition was determined by the xray powder diffraction method (xrd) using a philips instrument equipped with vertical goniometer pw 1050, cu tube, a graphite monochromator, and a proportional counter. unit cell dimensions of calcite were calculated by the unitcell software (holland & redfern, 1997) with the aim of determining the mg-content of the calcite on the basis of diagrams constructed by mackenzie et al. (1983) that show the relationship between unit cell dimensions and magnesium content of mg-calcites. concentration of fe, mn, mg and na in the valves was determined by the commercial acme analytical laboratories, canada by the icp-es method. the 0.5 g of the sample was leached for one hour with 3 ml of hot (95˚c) aqua regia and diluted to 10 ml. content of other trace elements (cu, nb, pb, rb, sr, u, zn, zr, y) was determined on an arl 8410 x-ray fluorescence (xrf) spectrometer equipped with rh-tube on pressed powder pellets, using a slightly modified procedure from nisbet et al. (1979). mass absorption coefficients for the wavelengths of measured lines were calculated assuming, in accordance with the results of performed xrd analyses, that all of the samples have practically the geologia croatica 57/1 73–79 7 figs. 3 tabs. zagreb 2004 key words: rudist valves, mineral composition, trace element content, turonian to upper santonian, istria, croatia. 1 institute for mineralogy and petrography, faculty of science, university of zagreb, horvatovac b.b., hr-10000 zagreb, croatia; e-mail: dtibljas@public.srce.hr 2 institute for geology and palaeontology, faculty of science, university of zagreb, zvonimirova 8, hr-10000 zagreb, croatia; e-mail: alan.moro@public.srce.hr 3 crosco, vukovarska 18, hr-10000 zagreb, croatia; e-mail: ostrezz@net.hr abstract turonian to late santonian limestones of southern istria are rich in rudist remains. the main aim of this study was to determine the mineral and chemical composition of 22 samples of rudist valves belonging to the genera durania, praeradiolites, radiolites, gorjanovicia and vaccinites, and to explain any observed differences. x-ray diffraction and chemical analyses showed that in all the analysed samples, the primary constituents of rudist shells, aragonite and low-mg calcite, were transformed into diagenetic low-mg calcite. the strontium concentrations of all the analysed shells correspond to pelagic bulk rock samples altered by diagenesis and are significantly lower than those for biological calcite. observed differences in the chemical composition of diagenetically altered rudist shells belonging to different rudist genera, namely a slightly higher content of sr in specimens of gorjanovicia and durania and lower concentrations of mg in shells of vaccinites are most probably the result of different shell structures and original mineral constituents. 74 geologia croatica 57/1 75tibljaš, moro & ostrež: mineral and chemical composition of rudist valves... same composition that correspond to the caco3. average accuracy of the xrf measurements, as compared to recommended values (govindaraju, 1994) for usgs (gxr–1 to 6), gsj (jb–2, jb–3, jf–2, jg–2, jg–3, jr–2) and igge (gsd–1 to 12, gsr–1 to 6) standard rocks was 4% for sr, 20% for pb, 12% for ga, 8% for zn, 14% for cu and 11% for ni. the precision of xrf and icp-es measurements was within several %, except when values were very close to the limit of detection (lod). the results of chemical analysis have been statistically processed by the statistica computer software (statsoft, 1995). besides descriptive statistical methods, discriminant analysis was used as it is a powerful tool for classifying individual cases (samples) into previously defined groups on the basis of multiple variables, with wide application in solving problems in geosciences (davis, 1986). for statistical analysis mn concentrations bellow lod were replaced with 70% of lod (miesch, 1976). 3. results phase analysis has shown that all the samples consist of just one mineral phase, almost pure calcite. no aragonite was registered. comparison of calculated unit cell dimensions of calcite with diagrams of mackenzie et al. (1983) revealed a very low magnesium content (0 to 2 mol %) (table 1). the results of chemical analyses of valves of selected rudist genera are given in table 2 while in table 3 relevant basic statistical parameters are presented. concentrations of niobium, zirconium, yttrium, uranium, and rubidium are not shown because in all analysed samples they were below the lod (app. 1 ppm for all of these elements except u for which the lod was 4 ppm). the results showed some differences in chemical composition of valves belonging to different rudist genera, although the content of most analysed trace elements is not influenced by rudist genus. the strontium content of valves of different genera varies significantly (fig. 2). praeradiolites, radiolites and vaccinites have very similar concentrations of strontium while the genera durania and gorjanovicia are differentiated by their remarkably higher concentration of strontium. generally, the low content of magnesium, already inferred by x-ray investigations, is especially low in vaccinites (fig. 3). minor differences were also observed in the sodium content, rudists of the genera durania and vaccinites are characterised by lower concentrations of na (fig. 4). these differences in chemical composition were confirmed by discriminant function analysis. the results of this analysis, though limited due to the number of samples on which analysis has been based, are represented by fig. 5 and tables 4 and 5. these results suggest that each rudist genus has a moderately distinct chemical composition, and samples of different rudist fig. 1 map with sampling locations (d1 – durania sample 1 etc., g = gorjanovicia, p = praeradiolites, r= radiolites, v = vaccinites; abbreviations are also used on figs. 2–5). simplified geology after polšak (1967a), moro (1997) and moro & ćosović (2000): 1 – cenomanian, 2 – turonian, 3 – coniacian–santonian, 4 – palaeogene. 74 geologia croatica 57/1 75tibljaš, moro & ostrež: mineral and chemical composition of rudist valves... a c c/a v sample å å å å3 mg mol.% d1 4.9788 17.0303 3.421 365.5904 1 d2 4.9861 17.046 3.419 367.0039 1 d3 4.9912 17.0459 3.415 367.7535 1 d4 4.9847 17.0357 3.418 366.5737 1 d5 4.9872 17.0248 3.414 366.7116 2 g1 4.9934 17.0473 3.414 368.1167 1 g2 4.9890 17.0695 3.421 367.9478 0 g3 4.9809 17.0424 3.422 366.1645 1 g4 4.9843 17.0279 3.416 366.3588 2 p1 4.9878 17.0509 3.419 367.3691 1 p2 4.9918 17.0564 3.417 368.0699 1 p3 4.9921 17.0426 3.414 367.8125 2 p4 4.9840 17.0441 3.420 366.6538 1 r1 4.9922 17.0452 3.414 367.8906 1 r2 4.9870 17.0497 3.419 367.2159 1 r3 4.9936 17.0687 3.418 368.6063 0 r4 4.9763 17.0387 3.424 365.4098 1 r5 4.9865 17.0344 3.416 366.8188 2 v1 4.9843 17.0611 3.423 367.0628 0 v2 4.9915 17.0709 3.420 368.3358 0 v3 4.9840 17.0487 3.421 366.7595 1 v4 4.9913 17.0467 3.415 367.7886 1 table 1 unit cell dimensions and inferred (after mackenzie et al., 1983) mgcontent of calcite in valves of different rudist genera. legend: r = radiolites, p = praeradiolites, d = durania, v = vaccinites, g = gorjanovicia. sample cu fe ga mg mn na ni pb sr zn ppm % ppm % ppm % ppm ppm ppm ppm d1 18 <0.01 3 0.20 <2 0.03 4 5 295 19 d2 2 <0.01 4 0.19 3 0.03 3 7 289 8 d3 9 <0.01 4 0.18 <2 0.04 5 4 256 12 d4 9 <0.01 4 0.22 9 0.03 4 6 442 13 d5 6 <0.01 4 0.23 <2 0.03 5 7 492 12 g1 9 <0.01 3 0.23 3 0.06 5 9 630 17 g2 11 <0.01 3 0.16 <2 0.07 3 6 540 16 g3 3 <0.01 4 0.05 7 0.01 4 5 220 10 g4 2 <0.01 4 0.12 11 0.07 3 4 465 10 p1 14 <0.01 3 0.16 <2 0.10 4 5 169 15 p2 12 <0.01 3 0.20 6 0.12 4 8 169 15 p3 2 <0.01 4 0.21 <2 0.04 4 4 239 9 p4 2 <0.01 4 0.17 <2 0.06 4 6 175 8 r1 14 <0.01 4 0.18 6 0.06 4 7 209 16 r2 17 <0.01 4 0.18 4 0.04 2 5 255 19 r3 9 <0.01 4 0.18 3 0.05 5 7 248 13 r4 7 <0.01 3 0.18 9 0.05 3 7 226 14 r5 1 <0.01 2 0.17 15 0.08 2 3 213 10 v1 2 <0.01 3 0.06 <2 0.02 4 7 158 9 v2 23 0.03 4 0.08 8 0.01 4 10 164 20 v3 12 0.02 4 0.07 3 0.01 7 6 182 15 v4 16 <0.01 4 0.06 5 0.02 5 5 258 16 lod 0.7 0.01 1.1 0.01 2 0.01 0.7 1.6 0.9 0.9 table 2 elemental concentrations in valves of different rudist genera. legend: r = radiolites, p = praeradiolites, d = durania, v = vaccinites, g = gorjanovicia, lod = limit of detection. 76 geologia croatica 57/1 77tibljaš, moro & ostrež: mineral and chemical composition of rudist valves... genera can be distinguished in discriminant space fairly well (fig. 5). 4. discussion according to xrd analyses, no remnants of bimineralic valves, which are otherwise characteristic for rudist shells (steuber, 2002) were found. this indicates diagenetic alteration of the studied valves and the transformation of aragonite to diagenetic low-mg calcite (dlmc). the grade of diagenetic alteration of calcareous fossils is often inferred from their chemical composition. as a result of meteoritic diagenesis mn and fe concentrations typically increase while sr and na concentrations decrease (brand & vezier, 1980; alaasm & vezier, 1986). measured concentrations of mn in the investigated rudist valves is quite low (table 2, fig. 6), well within the range of concentrations of rudist cu ga mg mn na ni pb sr zn genera ppm ppm % ppm % ppm ppm ppm ppm durania min. 2 3 0.18 <2 0.03 3 4 256 8 max. 18 4 0.23 9 0.04 5 7 492 19 mean 9 (6) 4 (0) 0.20 (0.02) 3 (3) 0.03 (0) 4 (1) 6 (1) 355 (105) 13 (4) gorjanovicia min. 2 3 0.05 <2 0.01 3 4 220 10 max. 11 4 0.23 11 0.07 5 9 630 17 mean 6 (4) 4 (1) 0.14 (0.08) 6 (4) 0.05 (0.03) 4 (1) 6 (2) 464 (176) 13 (4) praeradiolites min. 2 3 0.16 <2 0.04 4 4 169 8 max. 14 4 0.21 6 0.12 4 8 239 15 mean 8(6) 3 (1) 0.19 (0.02) 3 (2) 0.08 (0.04) 4 (0) 6 (2) 188 (34) 12 (4) radiolites min. 1 2 0.17 3 0.04 2 3 209 10 max. 17 4 0.18 15 0.08 5 7 255 19 mean 10 (6) 3 (1) 0.18 (0) 7 (5) 0.06 (0.02) 3 (1) 6 (2) 230(21) 14 (3) vaccinites min. 2 3 0.06 <2 0.01 4 5 158 9 max. 23 4 0.08 8 0.02 7 10 258 20 mean 13 (9) 4 (1) 0.07 (0.01) 4 (3) 0.02 (0.01) 5 (1) 7 (2) 190 (46) 15 (5) all samples 9 (6) 4 (1) 0.16 (0.06) 5 (4) 0.05 (0.03) 4 (1) 6 (2) 286 (136) 13 (4) table 3 the minimum, maximum and mean concentrations of trace and minor elements in valves of different rudist genera. standard deviations calculated from measured concentrations for samples of each genus are given in parentheses. data for fe are not given because most of the measured values are below lod. for calculation purposes concentrations of mn bellow lod were replaced with 70% of lod (miesch, 1976). fig. 2 strontium concentration in shells of different rudist genera. fig. 3 magnesium concentration in shells of different rudist genera. 76 geologia croatica 57/1 77tibljaš, moro & ostrež: mineral and chemical composition of rudist valves... recent marine bivalve calcite shells (steuber, 1999 and references therein), and diagenetic alteration is indicated only by concentrations of sr which are much lower than in recent shells. observed sr concentrations are significantly lower than those presented by several authors (mcarthur et al., 1994, 2000; podlaha et al., 1998; steuber, 2002) for biological calcite, but in good agreement with data for diagenetically altered pelagic carbonate rocks (renard, 1986). this is also visible in fig. 7, where the measured mg and sr concentrations cluster close to the regression line showing compositions of abiotic calcite. similar diagenetic trends, with mn and fe that are not elevated and low sr, were already observed by steuber (2002) in some rudist shells. therefore, the same author considered that mg/sr ratios were the best indicator for diagenetic alteration of shells. the chemical pattern indicates that diagenesis ended with transformation of both primary constituents of the shells, aragonite and low-mg calcite (lmc), into dlmc, despite the fact that lmc is considered to be relatively stable in a meteoric environment. according to the measured low mn and fe contents there was no precipitation of late ferroan calcitic cement. transformation processes were most probably accomplished in the vadose or phreatic–meteoric zone (al-aasm & vezier, 1986). the results of chemical and discriminant analyses point out that the chemical content of shells of different rudist genera is rather distinct. due to the fact that analysed shells are diagenetically altered, chemical composition of the shells should be primarily the result of diagenetic processes. these processes are controlled by a fig. 4 sodium concentration in shells of different rudist genera. fig. 5 plot of discriminant scores along function 1 vs. function 2, to discriminate rudist valves of different genera. discriminant function 1 2 3 4 log sr -1.48068 -0.568105 0.373568 0.082307 mg 1.53415 -0.542829 -0.489472 -0.036865 mn 0.02954 -0.266035 -0.307657 -0.992138 na 0.10066 0.209920 1.068870 -0.010185 eigenvalue 7.36468 1.586070 0.949597 0.285667 % of variance – relative 72.30 15.57 9.33 2.80 % of variance – cumulative 72.30 87.87 97.20 100.00 table 4 standardised discriminant function coefficients and related statistics. percent correct durania gorjanovicia praeradiolites radiolites vaccinites durania 100.00 5 0 0 0 0 gorjanovicia 75.00 0 3 0 0 1 praeradiolites 75.00 0 0 3 1 0 radiolites 100.00 0 0 0 5 0 vaccinites 100.00 0 0 0 0 4 total 90.91 5 3 3 6 5 table 5 classification matrix; rows contain number of samples in each observed group while in columns the number of samples in a predicted group are given. 78 geologia croatica 57/1 79tibljaš, moro & ostrež: mineral and chemical composition of rudist valves... variety of factors, such as their original mineralogy and chemistry and shell structure, and the physicochemical properties of diagenetic fluids and their position in the sedimentary column. it can be reasonably presumed that the latter factors were practically the same for all the analysed samples, since their sampling positions were very close, and cretaceous limestones are only slightly tectonically deformed (polšak, 1967a). strontium concentrations measured in valves of different rudist genera was slightly variable. a possible explanation for different sr contents lies in the fact that some analysed shell material most probably contained a considerable portion of diagenetic cement (al-aasm & vezier, 1986; steuber, 1999), which frequently has lower sr concentrations than a biogenic one, so consequently the measured concentrations were lower. the presence of diagenetic cements is due to the cellular structure of the outer shell of most radiolitids which allows entrance of diagenetic fluids and cement formation (al-aasm & vezier, 1986; steuber, 1999; regidor-higuera et al., 2002). the highest measured sr contents were observed in gorjanovicia, a radiolitid rudist with a compact, fibrous prismatic structure, similar to that of most hippuritids, in which the proportion of diagenetic cements was probably the lowest. relatively high sr concentrations were also observed in durania. although it has an open cellular structure, the wall structures (funnel plates and muri) are relatively thick which increases the proportion of biogenic calcite. low sr concentrations measured in radiolites and praeradiolites could be explained by a higher amount of diagenetic calcite in the analysed material due to their very thin shells with typical radiolitid microstructure. however, the low sr concentration in the hippuritid cannot be explained by shell structure alone, because its compact structure inhibits access of diagenetic fluids, and it is probably the result of the primary mineral composition. hippuritid shells have a greater proportion of aragonite (steuber, 2002) which is less stable then lmc in the diagenetic environment, and consequently they will be more diagenetically altered. the observed low mg content of vaccinites is most probably also influenced by their structure, primary mineral and chemical composition. unaltered shells of vaccinites contained less mg because a significant part of them was composed of aragonite, and the more compact structure inhibited sub-marine cementation by high-mg cements which could result in the lower mg content of altered shells. 5. conclusions mineral composition and trace element contents were obtained in order to find possible differences in rudist genera from specimens that were taken from pure carbonates without the influence of terrigenous material. in all analysed samples, the primary constituents of rudist shells, aragonite and low-mg calcite, are transformed into diagenetic low-mg calcite. measured strontium concentrations of all analysed shells correspond to pelagic bulk rock samples altered by diagenesis and are significantly lower than those for biological calcite. observed differences in the chemical composition of diagenetically altered rudist shells belonging to different rudist genera, namely the higher strontium content in gorjanovicia and durania, and lower magnesium content in vaccinites, are most probably the result of diffig. 6 ranges and means of mn and sr concentrations in rudist valves from southern istria compared with concentrations of modern bivalve calcite shells represented by the shaded area (steuber, 1999 and references therein). symbols: ◊ = durania, ■ = gorjanovicia, ○ = praeradiolites, □ = radiolites, ● = vaccinites. fig. 7 ranges and means of mg and sr concentrations in rudist valves from southern istria compared with mean compositions of modern biotically (solid line) and abiotically (broken line) precipitated calcite (carpenter & lohmann, 1992). symbols as in fig. 6. 78 geologia croatica 57/1 79tibljaš, moro & ostrež: mineral and chemical composition of rudist valves... ferent shell structures, i.e. openness of the structure for diagenetic fluids and cement precipitation, and different primary mineral and chemical compositions. acknowledgments we are grateful to thomas steuber and javier elorza for their thoughtful reviews and more than helpful suggestions. the study has been financially supported by the ministry of science, education and sport of the republic of croatia (projects 119315, 0119402 and 0119412). 6. references al-aasm, i.s. & vezier, j. (1986): diagenetic stabilization of aragonite and low-mg calcite. i. trace elements in rudists.– journal of sedimentary petrology, 56, 138–152. brand, u. & vezier, j. (1980): chemical diagenesis of a multicomponent carbonate system. i. trace elements.– journal of sedimentary petrology, 50, 1219–1236. carpenter, s.j. & lohmann, k.c. (1992): sr/mg ratios of modern marine calcite: empirical indicators of ocean chemistry and precipitation rate.– geochimica et cosmochimica acta, 56, 1837–1849. davis, j.c. (1986): statistics and data analysis in geology.– john wiley and sons, new york, 646 p. govindaraju, k. (1994): 1994 compilation of working values and sample description for 383 geostandards.– geostandards newsletter, special issue, 18, 158 p. holland, t.j.b. & redfern, s.a.t. (1997): unit cell refinement from powder diffraction data: the use of regression diagnostics.– mineralogical magazine, 61, 65–77. mackenzie, f.t., bischoff, w.d., bishop, f.c., loijens, m., schoonmaker, j. & wollast, r. (1983): magnesian calcites: low-temperature occurrence, solubility and solid-solution behavior.– in: reeder, r.j. (ed.): carbonates: mineralogy and chemistry. reviews in mineralogy, 11, 97–144, mineralogical society of america. mcarthur, j.m., kennedy, w.j., chen, m., thirwall, m.f. & gale, a.s. (1994): strontium isotope stratigraphy for late cretaceous time: direct numerical calibration of the sr isotope curve based on the us western interior.– palaeogeography, palaeoclimatology, palaeoecology, 108, 95–119. mcarthur, j.m., howarth, r.j. & thirlwall, t.r. (2000): definition of late cretaceous stage boundaries in antarctica using strontium isotope stratigraphy.– journal of geology, 108, 623–640. miesch, a.t. (1976): geochemical survey of missouri – methods of sampling, laboratory analysis and statistical reduction of data.– u.s. geological survey professional paper, 954–a, washington, 39 p. moro, a. (1997): stratigraphy and palaeoenvironments of rudist biostromes in the upper cretaceous (turonian– upper santonian) limestones of southern istria, croatia.– palaeogeography, palaeoclimatology, palaeoecology, 131, 113–131. moro, a. & ćosović, v. (2000): the rudists of southern istria – an example of environmentally induced succession within santonian limestones.– rivista italiana di paleontologia e stratigrafia, 106, 59–72. nisbet, e.g., dietrich, v.j. & esenwein, a. (1979): routine trace element determination in silicate minerals and rocks by x-ray fluorescence.– fortschritte der mineralogie, 57, 264–279. podlaha, o.g., mutterlose, j. & veizer, j. (1998): preservation of δ18o and δ13c in belemnite rostra from the jurassic/early cretaceous successions.– american journal of science, 298, 324–347. polšak, a. (1967a): osnovna geološka karta sfrj 1: 100.000, list pula l33–112 (basic geological map of sfry, sheet pula).– institut za geološka istraživanja zagreb, savezni geološki zavod, beograd. polšak, a. (1967b): kredna makrofauna južne istre (macrofaune crétacée de l’istrie méridionale, yugoslavie) [cretaceous macrofauna of southern istria, yugoslavia – in croatian and french].– paleontologia jugoslavica, 8, 219 p. regidor-higuera, i., garcía-garmilla, f. & elorza, j. (2002): cathodoluminiscence as a tool for microstructural and diagenetic analysis in rudist shells (hippuritacea bivalvia) from the upper cretaceous of northern burgos (spain).– in: vlahović, i. & korbar, t. (eds.): sixth international congress on rudists, abstracts and excursion guide book, rovinj 2002, 59–60, zagreb. renard, m. (1986): pelagic carbonate chemostratigraphy (sr, mg, 18o, 13c).– marine micropaleontology, 10, 117–164. statsoft (1995): statistica for windows.– computer application, statsoft inc., tulsa. steuber, t. (1999): isotopic and chemical intra-shell variations in low-mg calcite of rudist bivalves (mollusca–hippuritacea): disequilibrium fractionations and late cretaceous seasonality.– international journal of earth sciences, 88, 551–570. steuber, t. (2002): plate tectonic control on the evolution of cretaceous platform carbonate production.– geology, 30, 259–262. manuscript received march 24, 2003. revised manuscript accepted may 04, 2004. 80 geologia croatica 57/1 geol. croat. 51/2 105 . 134 23 figs. zagreb 1998 remains of sauropoda (reptilia, saurischia) in the lower cretaceous (upper hauterivian/lower barremian) limestones of sw istria (croatia) fabio marco dalla vecchia key words: dinosauria, sauropoda, titanosauriformes, diplodocimorpha, upper hauterivianlower bar­ remian, cretaceous, istria (croatia). abstract remains belonging 10 sauropod dinosaurs have recently been dis­ covered in upper hauterivian/lower barremian (lower cretaceous) limestones of sw istria (croatia). the material consists of a complete cervical vertebra, a nearly complete cervical centrum, fragmcnls of poss ibl e cervical ribs, three partial dorsa! and five more or less in­ complete caudal vertebrae, parts of caudal neural spines, a chevron, the distal pari of a femur, the proximal portion of a tibia and other fragments of bones. the bones were collected randomly from the sea bottom, therefore despite the fact that they come from the same out­ crop, the same level and probably the same bed, they cannot be assigned with certainty to the same taxon. their vastly different sizes indicate the presence of several individuals while different morpholo­ gies suggest the probable presence of more than one taxon. the com­ plete cervical and the anterior 10 mid-caudal vertebrae present a more strict affinity with brachiosauridae, a proximal cervical centrum rese­ mbles those of "cholldros(eosourtls", and a caudal neural spine is si­ milar to those of the camarasaurids. the dorsal vertebrae have pecu­ liar features (a very tall neural arch, well developed laminar complex, etc.) and characters suggesting their assignation to basal titanosauri­ formes and, possibly, to diplodocimorpha. a posterior dorsal verte­ bra testifies the presence of a new diplodocimorph similar to reh­ bachisollrlls but more primitive. 1. introduction dinosaur tracks of cretaceous age are relatively common in the lstrian peninsula (nw croatia), and have recently been reviewed by dalla yecchia et al. (1993), dalla yecchia & tarlao (1995) and dalla yecchia (1997a, b. c). they are preserved in upper barremian, upper albian and upper ceno­ manian limestones at several sites along the coast of the peninsula, and on the islands (main brijuni/brioni island, fenoliga isle[, e[c.). the first discovery of dinosaur bones, on the adriat­ ic sea bottom at the kolone locality near bale/valle vil­ lage, south o/" rovinj, was reported by boscarolll e[ al. (1993), and was fo llowcd by preliminary notes concern ing the fossils and their stratigraphic and palamuseo pa[eontologico cittadino, via valentinis 134, 1-34074 mon­ fa1eone (gorizia), italy. eoenvironmental context (dalla yecchia, 1994a. b; dalla yecchia et a!., 1993; tunis et a!., 1994; kozaric et ai., 1996). some specimens were identi · fied as sauropod bones (dalla yecchia, 1994b. 1997a. b, c; dalla yecchia & tarlao. 1995) but never described in detail. this paper presents a deta­ iled description of the identifiable and attributable remains of the sample. all of the material comes from the same outcrop, from the same stratigraphic level and, probably from the same bed (see below). however, most were collected randomly as scattered fragments on the beach and on the sea bottom, where the fossi liferous layer crops out. no systematic attempt had been made to collect the numerous bones still embedded in the rock. since the fossiliferous bed, which seems to be particularly laden with bony remains (d. boscarolli, pers. comm.). lies below sea level, its excavation is difficult. howev­ er, this outcrop promises to be one of the most rich and interesting of present europe. 2. depositional environment and age the age and depositional environment of this depo­ sit are discussed in boscarolli e[ al. ( 1993), tu· nis et a!. (1994) and din! e[ a!. (1998). the fossilifcr· ous outcrop is characterized by the presence of beds of oncolitic rudstone with bone debris, and thinly laminat­ ed limestones with plant, shrimp and fish remains. so­ me bones (for example, the complete cerv ical vertebra wn·yi, the small clorsal mpcm·yi , [he mid·caudal nos ig -i and other fragments) were preserved wholly in a yellow, thinly laminated limestone or with a side of the fossil in this laminated limestone and the other side in a grey, hard oncolitic rudstone. this seems to indi­ catc that the preservation of comp lete bones is due to deposition in a relatively protected, low energy environ­ ment (laminated limestones) and to the probably rapid covering by the rudstone which testifies a high energy environment. however this shou ld be confirmed by a detailed sedimentological and taphol1omical study of the fossiliferous beds which is beyond the scope of this paper. the stratigraphic sequence of the olilcrop at bale is composed of subt idal, intertidal and lacustrine limesto­ nes, the lower section is of late hauterivian/early 106 barremian age due to the presence of the foraminifer campanellll/a capllensis de castro; the upper scc­ tion is probably lower barremian (boscarolli ct ai., 1993; tunis et ai., 1994). therefore the bones des­ cribed here arc the oldest record of dinosaurs curremly known in istri a (dalla vecchia & tarlao, 1995) if possible sauropod tracks in the berriasian of fantazija quarry (lockley et ai. , 1994) arc exclud­ ed. the bones arc approximately coeval with the thero­ pod pes and sauropod manus prints found in a quarried limestone block from the cansiglio plateau (northeast­ crn italy, pordenone) described by dalla vecchla & ventur ini ( 1995) . the sauropods of bale are a rare case of dinosaur bone remains that are dated in cor­ relation w ith the marine biochronology. 3. description and comparison the sample consists of more than 200 specimens, most of whi ch are just bone fragments. the collected material was exposed to recent marine and shore weath­ eri ng and was encrusted (and som etimes pierced) by living mar ine ani mals and algae. it was c leaned and prepared by the preparators of the gmppo spejcologico monfalconese a.d.f. at the museo paleontologico cit ­ tadino of monfalcone (gorizia). most of the bones are crushed, sometimes strongly, but olherwise the state of preservation of the bones still imbedded in the rocky matri x is very good. onl y bones attributable to sauro­ pods are describcd hcre; several specimens are too frag­ mented to ident ify the skeletal element to which they belonged, other fragments belong obviously to long and large bones which remain indetenninate. the specimens wi ll finally be stored or exhibited in a museum dedicated to the local dinosaur rema ins in the vi llage of bale (istria, croatia). at present they are without the defini tive number of this museum therefore j will report here the numbers used during preparation (mpcm-v = museo paleontologico cittadino di mon­ falconc valle). the specimens that were nol numbered during preparation and were at the mu seum in ba le during the final version of this paper are identified with the abbrev iat ion wn-v. two bones are presently in the collection of the institute of geology, zagreb (nos lgi and nos ig-2). because of the way the specimens were collected it is im possible to be immediately sure that they belong to the same taxon, or to a precise number of different taxa. in some occurrences, for example in some levels of the morrison formati on (upper jurassic) of north ameri ­ ca, six sauropod genera were found together (see cur­ tice & wilhite, 1996). therefore each bone is com­ pared with the corresponding bones of described sauro­ pod taxa, in o rder to determine affin iti es particul arl y with the better known forms (brachiosaurus riggs , haplocanfhosaurus hatcher, camarasaurus cope, dip/odocll s marsh , and apatosallrus marsh ) and the neocomianbarremian ones. geologia croatica 51n acronyms: cd = caudal rib , cdl= centrodiapo­ physial lamina, cpr = centroprezygapophys ial lamina, co=eondyle, copr=condyloprezygapophysial lami­ na, dp=diapophysis, has=art icular surface for the hy­ posphene, hl= horizon tal lamina (= diapo-prezygapo­ physial lamina , diapo-postzygapophys ial lamina), i-ipn = hyposphene, hyp = hypantrum , idl = infradi­ apophysial lamina, ihpnl = infrahypos phellal lamina, ipdl = infrapostdiapophysial lam ina, lpdrl = infrapre­ diapophysial lamina, ippla = infraparapophysial anteri ­ or lamina, ipplb = infraparapophys ial posterior lamina, jprl = infraprezygapophysial lamina, ipzl= infrapost­ zygapophysial lamina, ispzl = inner suprapos tzygapo­ physial lamina, itpz= illtrapostzygapophysial lamina, l1ppl = lateral in fraparapophysial lam ina; l1pzl = lat­ eral infrapostzygapophysiaj lamina, na = neural arch, nc= neural canal, ns = neural spine, ospzl= outer suprapostzygapophys ial lamina, pl = pleurocoel, pp = parapophysis, pr = prezygapophysis, prl= prezygapo­ physiallam ina, prspl =prespinal lam ina, pspl = post­ spinal lamina, pz= postzygapophysis, scl = "core" la­ mi na of the neural spine, sdl=suprad iapophysiallam­ ina, siprl=subinfraprezygapophysial lamina, sprz= supraprezygapophysial lamina, spzl = suprapostzyga­ pophysial lamina. axial skeletal elements cervical vertebrae wn-vl (figs. i & 2; photographs in dalla vecchia, 1994b, fi g. 3, and dalla vecchia, 1997c, fi g. 2): two cervical vertebrae were preserved nearly in anatomical articulat ion. the posterior of the two is entire while only a posterior fragment (with the eoty le and the left postzygapophysis) of the other is preserved. the following description concerns the com­ plete vertebra (fi gs. i & 2). this is crushed latera lly, the neural arch is bent to the icft s ide and the left diapophysis with the corresponding ho ri zon tal lamina are crushed and bent to the centrum. the right s ide has been exposed to eros ion on the sea boil om in recent times and was strongly weathered. the centrum is opisthocoe lous, very e longate and tubular. its length is 350 mm , its height at the posterior end is 50 mm , the length/height ratio is therefore 7; maximum depth of the neural arch as preserved is 100 mm. the centrum has a cavernous, cancellate structure wi th thin external walls and re lative ly smail, irregular internal cavities bordered by bone septa and ridges; the septa and wall s are compa rat ive ly thicker than in the posterior cervical vertebra mpcm-v2 described below. the inner cavities are, at least in the anterior part of the centrum , antero-posteriorly e longated. a small pleuro­ coel, al so antero-posteri orl y e longated, is identifiable on the middle ventral part of the lateral side of the cen­ trum (fig. 2). "pleurocoels" are also present anteriorly on the centrum, just above o r at the base of the para­ pophys is. they ac tuaijy are deep depressions and do not appear to communicate with the inner part of the dalla vecchia: remains of sauropoda (reptilia, saurischia) in the lower cretaceous .. ns copr cpr cdl dp ipdl...: .. >,'. pz ~ hl " ..1~/ pr"i<{t;'i,;.:~~ ... '~~ ... ·.:!.,.~tti"-.:.l.'~~;~c pr~',h .. :· ~, pp ns ipzl lii!1t~m~\nc dp pp 107 fig. j cervical vertebra wn-vi . views: a) left laleral. b) dor­ sal, c) ventral, d) posterior. e) recon­ structi on in pos teri­ or view. acronyms: aspz= additional su prapostzygapo­ phys ial lamina. 108 geologia crorllic(l 51n ~ ... .. ...... ··· ·· <:'?:' )"~;'('~"6~~;.,~;c,';~;t'i ···i~jjklii::.;-·:·· · . centrum (they do not pierce the external wall) and are probably the aussenkaverne reported in the ccrvicals of brachiosaurlls branca; janensch by ja nensch ( 1947, fig. i) . small , rounded or oval (4-10 mm) shal­ low depressions arc present in the anterior part of the centrum , and are most prevalent on the latera l side of the neural arc h. ventral excavat ions arc not present. the " pjcurococls" and the depressions on the centrum are fi gured in fig. 2. the cotylc (the posterior articular cav ity on the cen­ trum) is deep and ova l (main vertical diame ter;:::: 50 mm) but the shape is probably biased by compression, and the condyle is well developed, ball-like and small (maximum diameter= 35 mm). the neural arch occupies nearly the entire dorsal surface of the centrum. the neural spine is low and not bifid. the parapophysis lacks the distal part and is ori­ ented in the vertical plane; despite any compressional e ffects it is unlike ly that this was originally oriented in the hori zontal plane. the diapophys is is triangular in dorso-iate ral view and tapers at the di stal tip , which is broken and shows a ci rcular outline of the section and a hollow insidc. the tip of the diapophysis and the poste­ rior margin of the anterior horizontal lamina are rough. from the diapophys is a well dcveloped wing-like hori ­ zontal lamina is direc ted anteriorly to the prezygapoph­ ys is and posteriorly to the poslzygapophysis. where the posterior horizontal lamina begins a strong infrapostdi­ apophysial lamina is al so obvious (fig. i c); this ends as a lamina at the dorsal-posterior third of the centrum and continues as a ridge with the rel ief tapering caudal­ ly, ending before reaching the caudal margin of the cen­ trum. where the infraposld iapophysiaj lamina attaches to the diapophysis, the posterior side of the latter beco­ mes wider and presents a shallow depression (this part has therefore a somewhat spoon-like aspect). there is a double, v -shaped inner centradiapophysial lamina (fig. i c), with the point placed in correspondence to the nar­ rowing of the tip of the diapophysis. the two branches of the lamina end at the dorsal-lateral part of the cen­ trum; the anterior one is wider and very thin. there is a fig. 2 cervical vertebra wn­ v i. pattern of pleurococls and small depressions. well developed centroprezygapophysial lamina, crushed against the anterior horizontal lamina, with a wide basal attachment on the dorsal-anterior part of the centrum, just caudal to the condyle. there is also a short condy­ loprezygapophysial lamina. the supraprezygapophysia l and suprapostzygapophys ial laminae are thin , well developed and separated (right from left) by very deep infra-supraprezygapophysial and infra-suprapostzy­ gapophysial cavit ies (fig. i b). the supraprezygapo­ physial laminae are thinner than the supraposlzygapo­ physial laminae. the ventra-poste rior part of the medial side of the supraposlzygapophysial lamina presents a deep cavity bordercd medially by a very thin vertica l lamina (aspz = additional suprapostzygapophys ial lamina). there are two thin , paralle l and short verlical lami­ nae just above the bony arch surrounding the neural cavi ty. the intrapostzygapophysial lamina reaches the­ se laminae medially fanning a y -shaped structure. the short verti cal lamina, infrapostzygapophys ial lami na and intrapostzygapophys iaj lamina surround a large, deep cav it y (fig. i e). right infrapostzygapophysial lamina and intrapostzygapophysial lamina arc crushed against one another and the corresponding cavity bor­ dered by the two laminae is nearly closed. the prezygapophys is is long and project s we ll beyond the anterior tip of the centrum. t he art icular surface is drop-shaped, fac ing medio-dorsally (orienta­ tion possibly partly modified by crushing). the postzy­ gapophysis is similar to the prezygapophysis in that the articular surface faces ventralaterally. the well devel­ oped, thin and wide (wing-like) horizontal lamina con­ nects the prezygapophysis and postzygapophys is to the diapophysis. comparisons elongated , " tube-like" cervical cen­ tra are present in brachiosaurus brancai, diplodocus and barosallnts lellllls marsh (mclntosh, 1990a, b). cervical centra of the camarasaurids are relative ly short and wide (osborn & mook , 1921 ; mcln­ tosh, 1990a, b). diplodoeids and camarasallrus have bifid neural spines in the cervi cal vertebrae (mcindall:t vecchi3: rejn3ins of s3uropoda (replil i3. s3urischi3) in the lower crclaceous ... 109 a tosh, 1990a, b; in diplodocus and camarasaurus they arc bifid from cervical 3 onwards) whereas they are single in brachiosaurus . t he distribution of the "pleurocoels" in wn-v i is similar, but not the same, as that of the anterior cervical vertebrae of brachiosaurus brollcoi (janensc h, 1950, figs. 20, 23, 26, 29). in fact, the size of the posterior pleurococl of the cenlrum is much small er in the descri bed specimen. al so the overall shape of the vertebra, the anterior elongation of the prezygapophysis, and diapophysis d ista ll y narrow­ ing in a bottleneck manner, are si milar to those of the anterior cervical s of brachiosaurus brancoi (janen­ sci-!, 1950, rigs . 20, 23, 26, 29). the internal cavi ties are probably the same as the " longi tudinal pneumatic tubes" observed in a presumed specimen of mamen ­ chisourus young by rus sell & z i-!eng ( 1993, p. 2089) and are present also in "chondrosleosaurus" (e.g. hulke, 1879, p. 756) and in another cervica l cenlmm described below. m pcm-vs (fig. 3a): this is the posterior part with the coty le o f a small centrum, w ith a basal-posterior fragment of the neural arch. the spec imen is strongly crushed; it is 11 4 mm long and its height at the coty le is 70mm. comparisons it is simi lar to the same region of the vertebra wn -v 1 and represents another cerv ica l verte­ bra belonging to a relatively small sauropod. mp cm -v6: th is speci men is probably the anterior portion (110 mm long) of a right in frapostdiapophysial lam ina from a rather large vertebra : the correspond ing part on the complete cervical wn-v 1 is no longer than 20mm. mpcm -v7 (fig. 3b): an incomplete posterior part of a postzygapophys is (48 mm long, 60 mm wide) cle­ arly belonging to a vertebra much larger than the com­ plete cervical vertebra wn-v i. fig. 3 a) mpcm -vs poslerior part of a small cervical centrum, right lateral view; b) mpcm -v7 incomplete post zygapophys is of a cerv ical vertebra, lateral view. the scale bar is in centimetres. m pc mv2 (figs. 4 & 5): a nearly complete cen­ trum, rather short , wide and low (leng th = 300 mm, height = 105 mm , and width = 175 mm at the posteri or end) (fig. 4). its low profi le is only partly due to dorso­ ventral crushing (the specimen, mainly in it s an terior part, is crushed becau se of its ex tremely cavernous internal struclllre). a small pal1 of the base of the neural arch is also preserved in the posterior part. t he neural arch, the parapophyses, and the external bony wall in the cranial hal f have all been weathered away. the posterior cotyle is rather deep and probably had an ell ipt ical shape, wider than high, with a rat io wjh = j .67. it s ventral side projects posteriorly more than the dorsal one. there are three large pleurocoe ls on both la te ra l sides (f ig, sa). t he external margins of the anterior pleuroeoel (apl) arc weathered away, there fore what we see now is probably slightly different to the original external shape. it is the shallowest of the th ree openings and is separated [rom the posterior (ppl) and lower pleuroeoel (lpl) by thin bony laminae. t he posterior pleurocoel is the largest and deepest openi ng (about 40 mm), ell ipt ical, craniocaudally elon­ gate, ex tending along most of the caudal half of the centrum. though deep, the posterior pleurocoels do not occupy the whole inner part of the centrum, and are not separated from each other only by a medial lamina (as in the dorsals of camaras(ji.ii"iis or brachiosaurus) . in faci the interior of the cent rum of mpcm-v2 is wholl y composed of smal l, honeycombl ike chambers. t he dorsal and ven tral rims of the pleurocoej are thick and liplike. t he anterior pl eurocoel is elliptica l and also anteroposlerior ly elongated. th is pleurocoel is deeper posterio rl y and becomes more and more shallow ven­ tro-ameriorly. it is separated from the posterior plcuro­ coel by a thin lamina. t he lower pleurocoel opens lat­ era-vent rally in the mid-anterior part of the centrum and is more developed ventrally (fig. 4d). its true out ­ line has probabl y been affected by weat hering on the lateral side where it poss ibly ex tended on the pa ra110 na ppl 10 em a b nc c o e geologia croa!ica 51/2 fig. 4 mpcm-v2, posterior cervical centrum. views: a) right lateral, b) left lateral , c) dorsal, d) ventral, e) posterior. acronyms: apl=antc­ rior pleurocoel, lpl =iower plcufocoel. ppl= posterior pleurocoel. dalla veeehia: remains of sauropoda (reptilia, saurischia) in the lower cretaceous .. , 111 na , , -----', pp a fig. 5 mpcm-v2. posterior cervical centrum. a) pattern of the pleu­ rococl s, b) cancellate structure of the condylar region (in the pic­ ture the vertebra is upside down and shows the ventral-anterior surface). acronyms as in fig. 4. pophyses. its present shape is elliptical and antero-pos­ teriorly elongate. the left one is partly subdivided into cells by thin bony septa. the weathered dorsal surface of the centrum shows the cancellate structure of the inner vertebra. more or less irregularly shaped cells are separated by very thin septa; in some places (as in the left upper-mid part of the centrum) these cells are regularly divided by verti ­ cal septa into a "honeycomb" pattern. a regular "hon­ eycomb" pattern, with antero-posteriorly elongated, tubular cel ls, is evident in the weathered anterior con­ dylar part (fig. 5b). the trace of the neural canal on the dorsal side of the centrum shows that it is very expanded at both extremities: maximum posterior (at the exit from the neuraj arch) width is about 50 mm , maximum anterior width is 55 mm, minimum width is at midlenglh (about 25 mm); height in correspondence to the posterior exit from the neural arch is about 35 mm. the posterior opening of the neural canal is therefore elliptical, wider than high. the ventral side of the centrum is very flat and wi thout longitudinal depressions or ridges. in the ante­ rior third the external, compact wall is weathered and the inner tubular, "honeycomb", cancellate structure is exposed (fig. 5b). in the mid-anterior part there is a median, antcroposteriorly elongate, large (length = 45 mm) and deep (about 40 mm) hole. in the mid-anterior part of the centrum , the ventral external bony wall nar­ rows because of the lower pleurocoel; here the medial margin of the opening is rimmed by the relatively thick wall. comparisons the large pleurocoels are very differ­ ent [rom the titanosaurid condition, and are characteris­ tic of brachiosaurids, camarasau rids and diplodocids (mai nly diplodocus). brachiosaurids and diplodocus­ like diplodocids seem to be excluded by the relative shortness and width of the centrum and its dorso-ven­ tral flatness (mcintosh, 1990b). the overall mor­ phology of mpcm-v2 and the size and position of the pleurocoels strongly resemble cervical 10 of camarasaurlls supremus cope (osborn & mook, 1921, figs. 7 & 32) and also the cervicals called c hondrosteo­ saul·lls gigas by owen (1876, see pis. ii-v). the latter are more or less coeval with mpcm-v2, being from the barremian wessex fonnation (blows, 1995) of eng­ land and have centra of the same proportions, overall outline, shape of articular surfaces, ventral aspect, very similar anterior pleurocoel and posterior pleurocoel and the particular, regular cancellate, "honeycomb" bone texture, mainly in the condylar region (see pis. ii , iv and v of owen, 1876 and the description by hulke, 1879, p. 756-57). on the other hand, the cancellate tex­ ture is not present in camarasaurus (p. upchurch, pers. comm.). the size of mpcm-v2 is between that of the two specimens of c. gigas described by owen (1876, sec pi. v). they could differ in the presence and shape of the lower pleurocoel, but the shape and actual position of this opening in mpcm-v2 is effected by weathering which rubbed out completely the para­ pophyses, as reported above. also variation of position of the posterior, lower and anterior pleurocoels may account for the differences. therefore mpcm -v2 at the present state of knowledge should be referred to this taxon, whose validity, however, is doubtful (see below). c. gigas was based by owen (1876) on only a com­ plete and a weathered cervical centrum. hulke (1 879) added at least another cervical centrum (n. 144, coli. h of hulke, 1879) (actually he made a mistake in reporting the name and attributed it to c. magnus). c. magnus (= bothriospondylus mag nils owen, 1875 but type of ornithopsis hulkei of seeley, 1870) is repre­ sented by two dorsal centra found in the same forma­ tion and locality of the cervicals called c. gigas (owen, 1876, p. 7). it appears plausible that c. mag­ nus belongs to the same taxon of c. gigas as partly real­ ized by owen himself, who referred them, "provisional ­ ly", to distinct species on the base of the incorrect state­ ment that they are both dorsal elements and that dorsals cannot be so different in the same species (p. 7). c. mag nus was based on a vertebra (bmnh 28632) which owen (1875) had called bothriospondylus mag nus before recognizing its resemblance to the vertebrae of 112 c. gigas. vertebrae of c. magnus (= ornithopsis hulkei) have the same honeycomb-like texture in the condylar region as c. gigas (owen, 1875, pi. ix). bmnh 28632 was indicated as one of the two types of ornithopsis hulkei by seeley (1870) but owen (1876) rejected the name as "misleading" because of its greek meaning which seems to suggest it is a bird bone. hulke (1879) considered eucamerotus hul­ ke and ornithopsis to be synonyms because the type of the first (bmnh r2522, a partial neural arch), bmnh 28632 and a "mutila ted centrum , reta ining enough of the arch and superstructures" (p. 755) present an "extre­ mely large-celled cance llous ti ssue" (p. 755). l yd­ ekker (1888) accepted the synonymy of chol/dros­ teosaurus (both species) and omithopsis but suggested that pelorosaurus mantell should be synonimized. in his recent review of ornithopsis blows (1995) does not include in o. hulkei the cervical vertebrae of c. gigas but considers it, as seeley ( 1870) did, as a lectotype of o. hulkei one of the two dorsal centra (the syntype of seeley, 1870, bmnh28632 see l yd­ ekker, 1888) called c. magi/us by owen (1876). c. gigas was recently considered valid and tentatively assigned to the camarasauridae by mcintosh (i990b, p. 387) because of its close resemblance with cerv ical 10 of camarasaurus. p. upchurch, who is rev iewing the british sauropod material, considers c. gigas a 110m en dubium and probably a member of the titano­ sauriformes (brachiosaurus + titanosauria) (p. upch­ urch, pefs. comm.). mpcmv4 (fig. 6): thi s is a part of a larger bone and has a peculiar and somewhat puzzling shape and structure. its identification is rather difficuil but it appears to be part or a laminar system of the neural arch of a cervical or dorsal vertebra of a sauropod. in fact, even if it is strongly clushed and its original shape was deformed by compression, the specimen is a ialt icem work of bone bridges and laminae, with pleurocoel-like openi ngs. this frame, linked to the extreme lightening of the skeletal elements, is typical of sauropod cervical and dorsal vertebrae. i chose an arbitrary orientation (see the caption of fig. 6) of the specimen to describe it and i identify the main lamina-like structures which compose it with the acronyms s i, s2, etc. that which follows should be considered a tentative description. s i is the upper, longitudinal, lamina-like structure which is strongly cru shed but not very derorm ed. its outline in the anterior part, where it is possibly fomled by two thinner lami nae now strongly clus hed one aga inst the other, is rec tangular in s ide view. at the anterior third, s i becomes rib-like (ar), the profile becomes inclined , the upper part enlarges and its dorsal margin is sharply acute. the back side of s i is nearly vertical; here the stlucture is divided inlo a ribmlike arch (bs) which reaches s2 and a thin, central and inner lamm ina (i/). s2 was originally nearly perpendicular to si but now is parallel to it because of crushing and deforgeologia croalica 51/2 mation. s2 resembles a thick lamina, thicker posteriorly than anteriorly, and hollow inside. a large, oval pleuro­ coel opens in its present s ide surface, revealing the hol­ low inside. s3 is the left side structure corresponding to s2 but was mostly weathered away. if so, si, s2 and s3 originally formed an upside down y or t-shaped structure. s4 is a lamina crushed against si, with a strong, rib-like upper margin (urn) and the remaining part (is) whieh is a thin sheet of bone crushed against il. the rib-like upper margin um begins in the dorsal mar­ gin of s i where the latter becomes rib-li ke; therefore the two rib-like structures form (and formed before crushing) a v -shaped st ru cture with the acute part pointing forward and downward. s4, now parallel to s 1 was originally diverging from the latter posteriorly. comparisons m the shape of the structure s 1 resem­ bles one of a low neural spine of a cervical vertebra. however, the re lation with the structure s4 cannot be recognized exactly in any described vertebra of hap/o­ cantllosaurus, diplodocus, apatosaurus and cama­ rasaurus (pers. obs.). the shape of the specimen mostly resembles one of the bifid cervical neural spine of apatosaurus (gilmore, 1936). as reported above, in my opinion it is part of a complex laminar structure of a neural arch of a rather large and bizarre cervical or dor­ sal sau ropod vertebra, but nothing more can be sa id unti l a more complete part of this structure is found. cervical ribs? (fig. 7) seven rod-like bone fragments (among them is mpcmv8, the others now on exhibit at balenalle are without number), with oval or elliptical cross sections (about 10.5 x j 4.5 mm in the longest fragm ent, the low­ er one in fig. 7,195 mm long). they have the same transverse sizes for all their lengths and are straight or slightly curved; they are not hollow and their surfaces present thin longitudinal striae. one surface is usually flatter (less convex) than the other. comparisons they cou ld be segments of the distal part of the shaft of long cervical ribs. they resemble the very characteristic, elongate rod-like shafts of the cervi­ cal ribs of camarasaurus, brachiosaurus, euheloplls romer and mamenchisaurus. on the other hand , mcintosh (1990a) indicates short cervical ribs as a diagnostic feature of diplodocidae. the identification as part of rib shafts is supported by the presence in the outcrop of si milar bone fragments more than 500 mm long and perhaps as long as 1200 mm (d. bosca­ rolli and f. bacchia, pers. comm.). if the identifi­ cation is correct, their large size excludes them from belonging to a vertebra of the same size as the complete cervical vertebra wn-v i ; they belong to a much larger vertebra of a large individual. despite this, the frag­ ments are very similar to the ossified tendons which strengthen the tail and the back of iguanodontids. how­ ever these ske letal elements are usually smaller and flatter. if the described specimens are ossified tendons there are two possibilities: 1) also iguanodontid s are dalla vecchia: remains of sauropoda (reptilia, saurischia) in the lower cretaceous ... ii] s1 s2 s1 2cm represented in the fossilifero us outcrop but we do not have other evidence of this, 2) there arc sauropods with ossifi ed tendons in the neck (calcified muscles are pre­ served in camarasallrlls d. chure, pers. comm. iii mclntosh, i 990b) or in the tail. dorsal vertebrae mpcm-vl (figs. 8 & 9): the specimen consists of a part ly preserved, small centrum and corresponding neural arch without most of the spine. the neural arch is strongly crushed antero-pos teriorly, due to the action of lithostatic pressure on the ex tremely ho ll ow struc­ ture. the whole vertebra is in fact just a very complex latticework of thin bone laminae. after complete prepa­ ration it seems clear that in previous papers i wrongly identifi ed the posterior part as the anterior (see dalla vecchia , 1994b, fi g. 4b). the an terior side of the verteb ra was strongly weathered and to identify the ® s1 s2 fig.6 mpcm -v4, possible frag­ ment of the laminar complex of a large cervica l or dorsal vertebra. a-b) "side" views, c) "fronc view. acronyms: a = "anlerior". p = "posterior", 5 i = lamina i . 52 = lamina 2, 53 = lamina 3, 54 = lamina 4. for the other abbreviations see lext. original st ructures is not possible or at best very diffi ­ cult. the centru m has a kidney-like outline in pos terior view, wider than high (about 80 x 55 mm) and the arti ­ cular face is concave, it is a cy linder, therefore it has convex lateral sides. on both la teral s ides there is ev idence of a very large pleurocoel, probably with an ovate outline (but see below) occupyi ng most of the lateral side of the centrum (figs. 8d & 9c). the pleurocoel is not a hole piercing the lateral wall of the centrum and in connec­ tion with its hollow inner part (fig. 8b). it is just a deep depression rimmed ventrally (lip-like ventral marg in), opening dorsally and partially uust in the vent ral part) divided internally by a small, rib-like vertica l septum (as in the dorsals of ellcamerofu5 sensu blows, 1995 and many other sauropods). the inner st ructure of the centrum is ex tremely cavernous, cancellate, wi th thin ve rti cal scpta (ma inly antero-poste riorly oriented but some smaller ones arc transversally oriented) and rein­ forc ing strut s (fig. 8b). the inner septa are as thi n as less than i mm, whcreas the external wall is thicker. the neural canal is oval, large, about 29.5 mm wide and 21 tlll1l high in posterior view, 25 and 16 mm respect ive ly in anterior view. the neural arch is comparalively very lall: the ratio 11/h (h = distance between the base of the postzygapo­ physis and the top o f ihe centrum , and h =ccntrunl hcight ) is 1.83; the preserved part of the neural arch is 2.8 timcs the height of the cenrrum . the neural arch is formed by very thin , long laminae which arc difficult to ident ify because of the strong crushing; thcir original pos ition is tcntal ively recons tructed in figs. 9c and loll. the ri ght pos t zygapophysis is nearly completely preserved. it is connected to the pedicels by a strong, straight, venieallamina (infrapostzygapophysial lami ­ na). there is no suture between the basal pediccls and the upper part of the arch. between the two infrapostzy­ gapophysia! laminae the arch is depressed. perhaps the two infrapos rzygapophysiallaminae were connec ted by a thin , horizonlal inlrapostzygapophysial lamina btll c ru shing preveilis furl her clarification. the c ross-sec­ lion of the post zygapophysis shows pneumatic cavi ties ins ide ; the part with cav ities is found dorsally with respect 10 a 5 mm thick layer of spongy bone wh ich is just above the art icular surface. the latter faces ventro­ lateral ly and sligh lly anteriorly. there is no hypo­ sphene: medially to the postzygapophyses the (itch is deep ly depres sed and in the middle of the concavity there is th e basal part of a rib-like (probably broken) postspinallamina (fig. sa). the ar ticular surface of the prezygapophysis was probabl y borne by a large, triangular , dorso-iatcrally gcu logia cf()<lfica 51(2 rig. 7 fragments of proba­ ble ccrvic<li ribs. sc<l[c in centimetres. directed (in front view) structure, possibly formed by a thick, rib-like infraprczygapophysi.aj lamina at the late r­ al margin and a thinner prezygapopbysia l lamina at. the dorsal one (pigs. 8d & 9b). this apophysis is strongly crushed agains t the other laminae which comprise the neoral arch. nothing is preserved of the part of the prezygapophysis bearing the articular surface. a nother triangular structure (indicated wi th the acronym as in figs. 8b and 9b) seems lo start just above the neura l canal, tapers dorsally and ends against the p resumed prezygapophysial lamina . as in other vertebra thi s structure, which has been vcry damaged by weathering . is composed of a lalliccwork of very thin laminae. above these structures therc is the base of the neur­ al spine. the rib-like trace of a possibly b if:i d (o-shaped in cross-section, fig. 10) prespinal lam ina can be recog­ nized, with also the basal part of both supraprezy­ gapophysial laminae. the latter taper toward the top and have a thickened margin in the upper half of the preserved part. the pattern of lateral laminae is very complex (figs. 80, 9c & 10). a wide and very th in lateral infrapostzygapophysia l j(jlllin a s ta rts from the la te ral side o f the base of rhe pedicel and rcaches the posterior horizontal lami na j ust an terior to the postzygapophysis wigs. 8d & 9c). the thi n infradiapoph ys ia l lam in a seems (0 start from ihe sa me poin t as the lat.eral infrapos(zygapo ­ physia l lamina (or a little above) and ends at the d ia­ pophysial "knob". most of the diapophysis is complele­ iy weathered. and is recogni zab le only as a knob or strut, composed in its proximal part by the confluence of the laminae connected with it. the nat.ural, unbroken outer margin of the infradi apophysial lamina is pre­ served in its basal part and shows that the infrad iapo ­ physial1amina was upwardly and laterally directed; thi s dalla vecchia: remains o f sauropoda (reptilia, saurischia) in the lower cretaceous .. . pspl pspl 2 em sprz sdl? --i,~ llpzl ipllb c prspl sdl prspl pr? .i--;c;fi pd r l iprl pp i.",:: ~4siprl iplla pl d 115 pl fig. 8 mpcm -vi, anterior dorsal vertebra. views: a) posterior, b) anterior, c) len latera!, d) right lateral. acronyms: as=anterior structure between prezygapophyscs. 116 pspl -,\_---,) '\ ' , ,itpz? 1 i ' i 1 ipzl 'l i .) , , a --pp pr? \ \ iprl \ prspl . , , b idl-­ lipzl -­ ipzl pl geo logia croatica 51!2 \ , , i , / c fig. 9 mpcm -v i, ant erior dorsal vertebra. simpl i fi ed drawing of the ve rtebra in a) pos terior and b) anterior vicw: c) reconstruction of lhe laminar paucrn in right lateral vicw. lamina appears 10 have been a wide, winglike structure projecting lalerally (fig. 9a). anteri or to the described laminae there is evidence of a complcx, laterally projccting structure placed at the b<tsc o f the neural arch. in my opinion thi s structure could be the parapophys is or part of it. the positi on of the articular surface of the parapophysis is not c lear. it is e ither the narrow facet shown in figs. 8d and 9c as the parapophys is, o r it was placed anteriorly and was weathered away. two ext reme ly thin laminae ( infra· parapophysial laminae, i ppla,b, fi gs. 8d & 9c) arc present at the base of the s tructure; they join dorsally forming an upside down v and border the upper part of a vacu it y connectcd with ihc plcurocoel. the rcsulting s truc ture is a drop·shaped dcep depression (fig. 9c) . the posterior lamina sta rt s from thc uppe r latero·postc· ri o r s id e o f thc ccntrum, the ot he r probably from thc upper lat ero· ant erior. the two laminae meet al thc pre· sum cd artic ular surface of the parapophys is. the laller co ntinucs dorsally as a short lamina which unites to anolher lamina (s ubinfraprezygapoph ys ial lamina ) coming probably from the uppcr latero· antc rior part of thc centrum. in posterior vicw two more or less c ircular dcep cavi ties arc visible respectivc ly at the base and at ihc top of this laminar sys tcm. these cavities are proba· bly true fea turcs of ihi s pan of th e areh even if th ey we re panly alt crcd by c ru shing. in lateral vicw, jus t above thc pres um ed parapophysis, two laminae bifur· cal c: a infraprcdiapophysial lamina (pos te ri orly) and the very thi ck , riblikc infraprezygapophys ial lamina (antc riorly). at the bifurcation thc infraprcdiapophysial lamina begins rc lative ly thick and hollow in s idc, but rapid ly tapcrs to becomc a ihi n, compact s inglc shce t of bonc. it was probably connectccl wi th the diapophysial " knob", but this part of the lamina is displaced because or s trong c ru shing. there is a thin horizontal lamina be tween the prezygapophys is and the diapophysial " knob", and from thi s to the postzygapophysis. a thin supradiapophys ial lamina can be idcntified but it is ve ry c rushed bc twecn the o the r laminae. the final pan, extending to thc diapophysial " knob", cannot be ide nti · fi cd w ith certainly, the inncr co re or the spine is an ant e ro· poste riorly dircctcd, rclatively thi ck lamina ("core" lamina of the neural spine , scl), forming an i· shaped s tructure wilh the supraprczygapophysial lami­ na , suprapostzygapophys ial lamina , postspinal lamina and prespinal lamina (and, of course , with the late ral insertion of ihe supradiapophysial lam ina) (fig. 10). comparisons· the probablc low pos ition of th e parapophys is and the absence of the hyposphcne (sec below) sugges t ihar thi s specim e n is an anter io r e le· ment, but not the fi rst: it may bc the 2nd to 4th since the parapophysis is not on the ccntrum. the small s ize of specimcn mpcm · vi would indicare thai it belongs to a juve nile individual. lack of fu sion of the ne ural arches to the centra is considered an important diagnostic rca· lure or immaturity (e.g coria , 1994: martin , 1994: cu rtice & wilhite, 1996) and has been observed in individuals or ma ny genera: c all1arasm/rlt .\· (ost­ rom & mcintosh , 1966). l/aplocalllitosa llrils (ha­ tciier, 1903), diplodoclls (curti ce & wilh ite, 1996), pa{arosall,.lis bonaparte (coria , 1994). pillii'ialgosa l,,"s martin , buffetaut & sute­ eti iorn (ma rtin. 1994). the pedieels of the neural dall:a vecchi:l: remains of sauropoda (reptilia, s;lurischia) in lhe lower crelaceous ... "' sprz prl? iprl hl llpzl ' hl lcm a pz pz fig. 10 ;vlpcf\ i.vi, anterior dorsal ven ebra. a) dorsal view. b) reconstruction orthe laminar pauern in dorsal view, arch or mpcm · v i a rc fused without evident suture to the centrum , therefore there is no evidence of immaturi­ ty except the small size. drop-shaped pleurocoels arc present in the anterior dorsa ls of camarosclllrlls "silpremlls" (osborn & mook, 1921. rigs. 8 & 9) and camar(ls(lurus grondis marsh (ostrom & mc intosii , 1966, pi. 23) and, less markedly, also in the mid-posterior dorsals or diplodoells eamegii iiatcher (hatciier. 1901, pi. vii), apalo.wllriis iollisae holland (g ilmor e, 1936, pi. xxv), a. exeel.ws (ma rs ii ) (g ilmore, 1936, pi. xxxi i) and in sollle dorsals venebrae or hap­ localilhosaliriis prisells hatcher (hatci ier , 1903, pi. i). i lowever the shape, s ize and posit ion of pleuro­ coels in dorsa l ve rt e brae arc nol always very reliable taxonomic features, since they c hange in the different clements even in the same individual, and in ihe same segmellt of the vertebral column (e.g g ilmore, 1936, p is. xxv & xxxii; hatcher , 1901, pi. vii, 1903, pi. i: ostrom & mcintosh, 1966, p is. 23-25). the specime n presents a peculiar, very high, neural arch. the anterior dorsal vertebrae of an immature camarasau/"lls grandis figured in ostrom & mcin­ tosii (1966, pi. 23-24) and lhe dorsals or rehba­ ehi.wllnts garashae lavocat (r ussell, 1996, rig. 30) have also a rather tall neural arch, and f-iapfocoli­ ,hosaurus priscfls is the sauropod with the highest sub­ zygapophysial part of the neural arch of the dorsal ver­ tebrae. the ralio ii /h (ii = distance between the base of the poslzygapophysis and the top of the cen trum , and h = centrum height) in the dorsal ?6 of liap/ocollflio­ sallnts prise lis ( iiatc iier , 1903, pi. i), dorsal 5 or camarasallrus "sllpremus" (osborn & mook, 1921, fig. 8) and an an terio r c10rsa l of the immature camarasgllrils grandis is 1.60, 1.37, 1.22 respective ly. in the diplodocimorph (sensu calvo & salgado, 1995) rebbachisallf'us lessollei calvo & salgado (calvo & salgado, 1995), in which the tall neural a rch is a diagnostic feature, h/h is 0.55 in an anterior dorsal and 1.1 in the posterior ones, whereas in the dar· salol' ii. ~amsb{je fi gu red in russell ( 1996, rig. 30) it is at a max imum 1.3. the arch of m pem· v i is the highest in every case, add itionally in the figured anteri­ or do rsals of h. prisc/ls and c grandis the shape of the centrum in posterior view is not kidney-like, the p leuro­ coel is smaller and the laminar paltern in the neural a rch is dirfercnl (hatcher , 1903; ostrom & mc intosh, 1966). un ro rtunale ly lhe mosl anterior dorsal vertebrae of sauro pods arc no t as well known and desc ribed as the mid-posterior ones. the absence of the hyposphcne-hypan lllll11 articula­ tion in lhe dorsals is reporled by salgado et a l. ( 1997) for tornieria and ornilliopsis (= eiical1lcrollls sensu blows, 1995; but omilhopsis has hyposphene­ hypanlrum, cf. h ulke, 1880, pi. iv), in rebbaciji­ sauriis lavocat (ca lvo & salgado, 1995; russell, 1996) and is comm on among titanosaurids (salgado e t ai., 1997). the absence of hyposphene­ hypantrul11 articulation in the pos terior dorsals is a synapomorphy of titanosauridac scns u salgado et a!. (1997). however the neural arch of thc titanoscluri­ dae is lower and the plcurocoel is much smaller and of a difrerent shape (bona parte & coria , 1993; bonaparte, 1996), lhcrerore they arc exclucled. fol­ lowing mc intos h ( i 990b, p. 362) the hyposphene­ hypanlru1l1 seems to be generally absent in ihe anterior­ most dorsals of sauropods. it is absent on the dorsal i (which has a cerv ica llike clspect) in hap /ocantho­ saui'iis prisclis but dorsals 2 5 are unknown and it is present in the dlher dorsal vertebrae ( liatciier , 1903). in h. iil1erbacki iiatc ii er lhe hyposphene­ hypanlrum is firs t see n on the dorsal 6 (hatciier, 1903, p. 34), while in comorasallflfs only dorsals 1-2 arc wilholit the hyposphenc (osb orn & mook, 192 1, p. 302), the dorscli vertcbra 4 or brachiosaurus bralleai has a well developed hyposphene (janen­ sc ii , 1950, fig. 54), whilc in dip/odoclls carllct::ii a hyposphcl1c is prescnt from dorsal 4 onwards but dor­ sals i and 2 are cervicallike. in aparosaurus e.xce /sw; the hyposphcne is present from dorsal 3 ollwclf(ls (g il­ more, 1936) and the pm'apophysis or 1 and 2 remains on thc cen trum. t here is somc s imilarity with dorsa l 2 of apatosaurus excelsus and a, /oflisoe but thc position of the parapophysis and its laminae arc different. fur­ thermore the shapc of thc neu ral spine was probably narrower (gilmore, 1936). large, coarse cavitations in the internal struct ure of the cent ra is considered a brachiosaurid feature by blows (1995), and a titanosaurirormes one by p. upc ii urcii (pe rs. co mm. ancl in press). following powell (1986) lhe great developmenl or cavernous ii' pr -jl-.--.hl pz spzl hl-ir--~~.! pz --i-'~ hpn pr prspl hyp sprl spzl pspl spzl pr pz geologia croatica 51/2 pp ihpnl hpn ihpnl scm ippl llpp sdl e ihpnl pz fig. 11 mpcm-v3, part of a neural arch of a posterior dorsal vertebra. views: a) anterior, b) posterior, c) right lateral, d) left lateral, e) dorsal. f) ventral, in these drawings broken surfaces are not showed by sloping lines. acronyms: has = art icular surface for the hyposphene. osseous tissue is a diagnostic character of titanosauri­ dac. astib ia et al. (1990, p. 463) consider the "cellll­ lar bony structure of the vertebrae" an "autapomorphic titanosaurid feature". however salgado et al. (1997, p. 26) consider that the "phylogenctic relcvance of the relative development of cavernous osseous tissue is unclear", in the dorsal vertebrae of brachiosaurus and camarasaurus the inner ccrtrum is camerate (large cavdalla vecchia: remains of sauropoda (reptilia, saurischia) in the lower cretaceou s ... 119 spzl sol sprl / \~ pspl g'-l..-' .... _ prspl o o a hl hpn has ihpnl io l fig. 12 mpcm-v3, part of a neural arch of a posterior dorsal verte­ bra. a) reconstruction of the laminar pattern in dorsal view, b) reconstruction of the preserved part of the basal neural arch in right lateral view. the has of the prezygapophysis is projected in the corresponding position on the hypospljene. ities) rather than cancellate. since the individual repre­ sented by mpcm-vi is very small, the extreme light­ ening of the vertebrae cannot solely be an adaptation to large size. mpcmv3 (figs, ii & 12; figured in dalla vecchia, 1994b, fig, 4a, and dalla vecchia & tarlao, 1995, fig, 2), this specimen represents the zygapophysial segment of the neural arch and the basal part of the neural spine of a dorsal element. the posi­ tion of the parapophysis and diapophysis suggests a mid-posterior position. it is 220 mm high and 200 mm wide, and therefore belongs to a large individual. some parts have been weathered so that the present margins seem to be the original margins of the bone but actually are nol. erosion destroyed the projecting part of the hyposphene, the complete transverse processes, most of the processes for the capitulum and most of the neural spine. the bone was strongly crushed antero-posteriorly and this affected mainly the laminae visible in lateral view (i.e. horizontal lamina, infradiapophysiallam ina, supradiapophysial lamina, elc.) which are therefore de­ formed and artificially approached, the specimen is composed of a latticework of thin lam inae, above all the axial part of the arch. also the thickest and strongest pal1s (i,e, zygapophyses) arc cav­ ernous. for example, a large deep cav ity divided by a thick septum (fig, lif) opens medially at the base of the prezygapophysis, just below the articular surface for the hyposphene, the prezygapophyses are large, with wide articular surfaces facing dorso-medially. there is a wide, more or less quadrangular articular facet for the hyposphene bordering the upper part of the hypantrum , and articu­ lating with the hyposphene, at the ventral end of thi s facet the prezygapophysis narrows fonning a step-like structure, (i.e. the articular surface for the hyposphene is on a low, ventro-medial projection of the prezygapo­ physis) and the prezygapophysis assumes a hammer­ like shape. a thin lamina starts from the base of the articular surface for the hypo sphene to reach the axis of the arch in the middle of the hypantrum, the hypan­ trum is very wide, deep and with an isosceles trapezium outline. the postzygapophyses arc united to the hyposphene form ing a very strong, y -shaped articular structure (fig, llb), the postzygapophysis art icu lar surface is very wide and elongated. the hyposphene is triangular and dorsoventrally elongate, but unfortunately the pos­ terior portion is strongly weathered. the hyposphene originally was probably much more developed posteri­ orly. in fact there is no clear indication of the presence of the accessory articulation, which should fit in the correspond ing steplike structure of the prezygapoph­ ysis, nor a complete articular facet corresponding to the articular facet in the prezygapophyses (has, figs, 11 & 12), the infrahyposphenallaminae start from the ven­ tral end of the hyposphene and arc ventrally and slight­ ly laterall y directed. the ventral cross-section of the specimen shows that the axial core of the neural arch is formed of a latticework of thin laminae (fig, il f), it is possible th at there was something like an infrahypo­ sphenal cavity entering the hyposphene from insi de the neural arch. the parapophysis stalk is preserved but weathered at the outer end, on the right side just behind the prezy­ gapophysis, on this side there is also a knob which is probably the proximal part of the "core" of the trans­ verse process (=diapophysis) since all laminae are con­ fluent to it (fig, 11c), on the left side, the position of the parapophysis and diapophysis is shown only by convergence of the laminae, since the processes have been completely removed by weathering (fig, lid), the position of the transverse process seems to be near the post zygapophysis in the left side, while it is midway between the postzygapophysis and parapophysis in the right one. 120 two laminae start from the base of the prezy­ gapophys is. the thin anterior lamina reaches the para­ pophysis an teriorly or in the middle, and is therefore an infraparapophysia\ lam ina. it borders posteriorly a very deep lateral depression excavated into the prczygapoph­ ys is . the poste rior lamina is very thick, rib-like, reach­ es the parapophysis posteriorly (fig. i i c), and is here ident ifi ed as a late ral infraparapophysial lam ina. the presence of a very thin infradiapophysia\ lam ina is clear on the left s ide (fig. ii d) while the ri ght one is very strongly crushed. the thin horizontal lamina was some what short­ ened, de formed and bellt to a s-shaped structure by antcro-posterior compression (figs. l i c-d). the supraprczygapophysial lamina is a thick lami ­ na. it has a wide base (about 70 mm) in front view and tape rs quickly toward the top of the preserved part, where it is at least 20 mm wide, and therefore does not end agai nst the presp in al lamina. interpretation of the ac tual morpho logy of this lamina is difficult since the rig ht one seems d i ffe rent from the left o ne, perhaps because of weathering and crushing. it was probably anteroiaterally directed (fig. 12a), wit h a thick, lip­ like anterior margin wh ich rims the deep, axial depres­ sion fo rmed by the two sllpraprezygapophysiallaminae, at the bottom of which the prespinal lamina starts. no bony struts or laminae seem to connect the supraprezy­ gapophys ial lam ina to the supradiapophys ial lamina. the prespinal lam ina is weathered and appears more as a rib than a lam ina. it probably did not project beyond the level of the supraprezygapophys ial lamina. it starts at the base or very ncar the base of the neural sp ine, becomes wider and stronger toward the lop and perhaps was bi fi d (but this aspect could be due to weathering), al least at the base. the suprapostzygapophysial lami nae, which are more a ffected by weat hering, mimic the sup raprezy­ gapoph ys ial laminae but are thicker above all at the base where they arc connuent with the postzygapoph­ ys is. the le ft one bifurcates just above the postzy­ gapophys is and becomes single again soon after (fig. 11 d-e) . a comp lex latticework of transverse laminae, thin in the basal part of the neural spi ne, th icker and strutlike above, connects the suprapostzygapophysial lamina to the supradiapophysial lam ina. t he postspinal lamina is similar and preserved like the prespinal lami­ na but its width is constant. the supradiapophysial lam­ ina is thinner than the suprapos tzygapophysial and supraprezygapophys ial laminae. there is a re latively sho rt "core" lam ina of the neural spine that means the spine was narrow in lateral view and rough ly of rectan­ gular appearance in cross-section (fig. 12a), at leas t at the apex of the preserved part. it seems narrow also in an tero-posterior view but it is impossi ble 10 know if it widened again above the preserved part or not. comparisons ihe presence of a med ial prespinal lamina in posterior dorsals is considered a synapomor­ phy of the t itanosaurifonnes [brachiosaurus brancai + (c/ii/bu tisaurus illsi~li is del carro + titanosauria)] geologia croat ica 51n sensu salgado et a l. ( 1997) and its development down to the base o f the neu ral arch is considered a character o f de ri ved titanosaur ids. however, titanosau­ ridae sensu salgado et a l. ( 1997) lack a hypantrum­ hyposphene complex in the posterior trunk vertebrae. a prespi nal lamina in poster ior dorsals is also p resent convergently in the diplodoeidae (op. eit.). ellcamero­ fils foxi blows, considered a brachiosaurid by b lo­ ws (1995), does not present a prespinal lam ina in \he posterior dorsals (see hulke, 1880, pi. iv, fig. 5). the development and morphology of the preserved supraprezygapophisial-prespinal laminae and supra­ postzygapophysial-postspinal laminae is similar to tho­ se of the diplodocidae (sec posterior dorsals of diplo­ dociis, hatcher , 1901 ; apatosaurus, gilmore, 1936, pi s. xxv & xxxii ; ali1phieoelias cope, os ­ born & mook, 1921 , fi gs. 11 9 & 120) ancll-japlo­ eal1thosallrus prisells (hatch er, 1903, pi. i). a nar­ row neural spine of the dorsal vertebrae is a lso a feature of the diplodoeidae. t he infrahyposphena l lami na and corresponding cav ity arc structures wh ich seem to be present only in the diplodocidae (curtice et ai., 1996) but apparent­ ly the posterior dorsa ls of eucameratus faxi also have them (see hulke, 1880, pi. iv , fig. 7). the steplike structure on the medial s ide of the prezygapophysis seems to be present a lso in the holo­ type of eilcoll1erotlls foxi (b lows , 1995, fig . i c). the whole prezygapophys is-hypantrum complex appears to be somewhat s imil ar, on the basis of blows (1995, fi g. i c) to that of the holotype of eueal1lerotlls foxi. however, the hypantrum -hyposphene art iculation is al so s imilar to that of some basal litanosaurs, and in particular that of the an terior dorsal of arrentinosourus ituilleulellsis bonaparte & coria, where the step­ like structure has been called "accessory articul ation of the hypantrum" (ef. bonaparte & cor ia, 1993, figs. 4 & 6), and is considered a d iagnosti c feature o f the genus (bonaparte & coria, 1993 , p. 272). as sugges ted by the authors themse lves (p. 276 , 280) the development of these structures is related to the large size of the individuals, and is therefore very probably a homoplastic character. the presence, absence or shape of lesser laminae on the neural a rch of sauropod dorsals probably lacks great taxonomi c value because of the variability ex isting in the same ind ividual (e f. diplodoells in hatcher, 190 j, and apatosaurus in gilmore, 1936). wn-v6 (fig. 13d-e), is a nearly comple te dorsal vertebra still under preparation , showing main ly its righ t and posterior side. the specimen will be stored at the museum of the municipality of bale and is at pre­ sent without number. it is less crushed than the othe r presacral vertebrae found in the outcrop. the right pedi­ cel of the neural arch is detached from the centrum and thi s co uld mean that it was no t completely fu sed to it (but c rushing should be cons idcred the main cause of this de tachment) and that the specimen does not belong dalla yecchia: remains of sauropoda (reptil ia, saurischia) in the lower cretaceous ... 121 pspl p pspl -.. dp a , \ , \ { ( \ i , i '---/ c p sp l --+-~;i ispzl fig. 13 mid-postcrior dorsal vcrtebrae in posterior view. a) dorsal 13 of haplocanfllosaurus priscu.\· (redrawn from hatc her. 1903), b) dor­ sal 5 of apatosall/"lls imdsae (redrawn from gilmore, 1936), c) mid-posterior dorsal of rehhachi.murus fessonei (redrawn from calvo & salgado, 1995), d) wn-v6, nearly complete posterior dorsal vertebra. e) postcro-lateral view of the neural arch of wnv6. to a fu ll y mature individual. the overall morphology and the relative position of the diapophysis and para­ pophysis indicate that it is a posterior dorsal vertebra. tt is larger than mpcm -v 1 and smaller than mpcm -v3 and has a characteristic tall neural arch, with long diapophysis extending sharp ly upward (the angle is about 45'). there is a hyposphene-hypantrum complex and the neural spine is undivided (but only the lower part is preserved). the neural arch is a latticework of thin and wide laminae. each suprapostzygapophysial lamina is double. the relatively narrow inner supra­ postzygapophysial laminae taper rapidly, coming toge­ ther to [onn a postspinallamina. the outer suprapostzygapophysial laminae are wide and antero-posteriorly directed. they run paraliel to the main axis of the spine, tapering upward, and abutting nearly perpendicularly the supradiapophyseal lamina (fig. l3e). a similar suprapostzygapophysial laminar pattern is sometimes present in the diplodocid apatosaurus (see gilmore, 1936, pi. xxv; here fig. 13b) . the diapo-postzy­ gapophyseal lamina (= hori zontal lamina) ends in the middle of the transverse process without reaching the diapophysial articular surface. the centrum is relatively small and elongate (its maximum dorso-ventral height is about 150 mm , and length is more than 200 mm), the articular facets are circular and a large pleurocoel is 122 present antero-do rsa ll y on the latera l side. the inner structure of the centrum is not cancell ate (i.e. it is finely spongy). comparisons the overall morphology is remines­ cent of the mid-posterior dorsal vertebrae of haplocgn­ lilosailrlls (fig. 13a) and rebbacilisallrlls lavocat (refe rence is made mainl y to r. lessonei calvo & salga do , albian-cenomanian of argen lina (fig. 13c), because ihe on ly prepared dorsal vertebra of r. garasbae la yocat, aptian ?cenomanian of moroc­ co, was never fi gured and was only poorly described by lavocat , 1954). reference 10 dieraeosauridae is excl uded by ihe presence o f ihe plcuroeoel (i he absence of pjcurocoels in the dorsal vertebrae is considered an import ant apomorphy o f d icraeosaur ids, see mcl n­ tost-i, 1990b). }-fap/ocamhosgurlls, which shares with the vertebra linder examination the hi gh inc lination of the d iapo ph ysis and the presence of the hyposphcnc­ hypantrum, has, on the other hand, a postspinal lam ina wi th a very different morphology, single suprapostzy­ gapophysia l lam inae, a taller subzygapophys ial portion of the neural arch, and is known presently only in the upper jurass ic of norlh america (mcintos h, 1990b). rebbachisaurlls does nol presel1l an oute r supraposlzy­ gapophysial lam ina (see calvo & salgado, 1995, rig. 9; here fig. 13c) and, mosl imporlanl , docs nol pre­ sent a hyposphene-hypantrum complex in dorsal verte­ brae (calvo & salga do, 1995). the neural spine or r. lessoflei is more slender in antero-posterior view ihan that of the specimen here desc ribed. however, the spine of r. garasbae is wider than that of the south american spec ies. the preserved part of the neural spinc of wnv6 is most reminescent of the neural spines of some dorsa l vertebrae of apatosaum s louisae (fig. 13b). characters present mainly in the diplodocimorpha (sensu calvo & salga do, 1995) indieale ihal lhe specimen belongs to this c lade: 1) the neura l a rch is three times the dorso-ventral centrum height (the height of ihe on ly part ia lly preserved neural arch is 2.85 limes the dorso-vcnt ral centrum height), 2) the suprapostzy­ gapophysiaj laminar pattcrn is relatively complex, wi th inner suprapostzygapophysial laminae whi ch are con­ riuent to form a postspinal lamina, and outer s upra­ postzygapophysia l laminae para llc l to the axis of the spi ne and taper ing upward, 3) the ta ll neural spine is re lat ively narrow in antero-posterior and latera l view. the early cretaceous dipjodocimorphs are repre­ sented mai nly by a g roup of gondwanian taxa (reb­ bachisaurus garasbae, r. tessonei , and the neocomian amargasallrus cazall; salgado & bonaparte from argentina) with ex tremely ta ll neural spines and upwardly directed d iapophyses in the dorsal vertebrae. t hi s sugges ts a gondwan ian affin it y of the islrian sauropod fauna. w n-v6 represents a new diplodocimorph taxon because of the combined presence of an hyposphene­ hypantrum compl ex, a well developed outer supra­ poslzygapophysial lami na running parallel to the ax is of geologia croalica sin ihe spine and a high (aboul 45°) incl inalion of ihe long diapophyses. it is very probab ly re lated to rebbachi­ sgurus but is less derived because of the presence of the hyposphenc-hypantrum in dorsa l vertebrae. the name hislriasaurlls hoscarollii is proposed for this new tax­ on, in honour of the discoverer o f the site, mr. dario boscarolli , and referring to the region where the speci­ men was found (his/ria = latin name of istri a). caudal vertebrae wnv3 (fig. 14). the spec imen was fi gured in bosca rolli e l al. ( 1993, fi gs. 25-27). the cenl rum is 100 mm long, 120 and 115 mm high respeelively al the anterior and poste ri or a rt icu la r side. the s hape of the art icular facets is roughl y e ll ipt ical, with the longer axis ( 150 mm in the anterior facet) horizontal. the pos­ terio r is nearly flat, the anter ior is a little weathcred and was o riginally flat or shall owly concave. the vcntro­ posterior part of the centrum projects downward and sli ghll y backward; this projeeli on is relaled 10 ihe chevron art iculation , but there is no clear mark of the art icular facet, only a th in , transversally fl at area. there are no plcurocoels and not even longi tud inal ridges or grooves on the ventral side. the ventral side is slightl y depressed bu t the cross-section o f the centrum is not "heart -shaped". the proximal parlor the coalesced cau­ dal rib is placed high on ihe dorsal-ialera l side of ihe cenlrum and is laterally and backwardly directed. the rib is spi ne-like and slighll y dorso-venlra lly n allened. the neu ral arch is on ly part ly p reserved. ii is la ll and placed an te riorl y on the centrum, so the distal third of the latter is not covered by the arch. the circu lar neural canal is very large. the ped icels are slightly medi a lly inclined. the postzygapophysis is far above ihe base of the neural canal and is posteriorly e longate. the articu­ la r facet is a shallow depression, an te rodorsa ll y-pos­ lerovenlrally e longaled , faci ng lalerally and only slighl­ iy venlra ll y, placed on ihe venl ral part of ihe poslzy­ gapophysis. the prezygapophyses are not preserved but the posi tion of the art icular facet in the poslzygapophy­ ses s ugges ts it was anteriorly and upward ly direc ted. the neural spine is not preserved but its base was rather far abovc the base of the neural canal. shortness of the centrum and the presence o f a strong rib idcnt ify this as an anterior caudal e lement. mpcm-vi4 (fig. 15), is a eenlrum lacking the pos­ ter io r half and wi th the basal part of the neural a rch. the centrum is more broad than hi gh (about 11 5 x 70 mm), with a kidney-shaped, concave ante rio r articu lar surface. the left rib (only the ante rior, basal part is pre­ served) placed on the dorsal-iatc ra l side of the centrum , is strong and probably latero-posteriorly directed. t here is a s ha llow depress ion in the centrum j ust below the ri b. the neural canal is subc ircular to oval and very large, of greater heigh i ihan w idlh (26 x 20 mm) in pos­ terior view, the opposite in front view. the neural arch is fused without suture to the centrum. the pediccls are slrong and inclined med ia ll y . the prezygapophyses dalla vccchia: remain~ of sauropoda (reptilia, saurischia) in the lower cretaceous ... 123 pz b pz a cd fig. 14 wnv3. anterior caudal vcl1ebra. views: a) right lateral, b) dorsal, c) anterior, d) posterior. lack the di stal part with the art icu lar surfaces . they start at the base of the neural arch and rise from the antcriormost part of the centrum , arc forwardly inclined at about 45 ° in s ide view, and are flattened late rally with the outcr s ide wh ich faces late ra ll y, upward and backward. on ly the basal anterior part of the neu ral spine is preserved. ii is not far above the base of the neural arch. the basa l parts of the prcsp inaj and supraprczygapophysial laminae are preserved. the neural spine appears to be caudally inc lined, at least in the basal part and its base was ante ro-posle riorly nar­ row. the evident shortness of the centrum and the pres­ ence o f a strong rib placed down on it identify it as an anterior caudal e lement. mpcm-vls (fig. 16) comprises most of a relat ive­ ly short centrum with a fragment of the right basal part of the neural arch. the right s ide of the centrum and , partly , the posterior arti cul a r surface are suffic iently preserved for description, the centrum is ellip tical, of greate r width than height (about 127 x 105 mm) in pos­ te ri or view, short (75-80 0101) , and with a prac tica lly flat posterior art icular surface. its shape was spool-like, 124 geologia croatica 51/2 prspl ld sprz 2cm ld fig. 15 mpcm -v 14, rragmentary anterior caudal vertebra. views: a) anterior, b) left lateral, c) posterior, d) dorsal. acronyms: ld = lateral depression. with a marked oval to semicircular depress ion in the dorsal lateral hai r just below the rib. the right rib (only the basal segment is preserved) is placed in the upper­ most, dorsalateral s ide of the centrum at the attach­ ment o f the ne ural arch. it is strong, s lightly flattened dorsa-ventrally and directed latero-posteriorly. the shortness of the centrum and the presence of a strong rib identify it as an anterior caudal element. nos ig-l (fig. 17, photograph in dalla vec­ chia, 1997c, fig. 4). the centrum is nearly complete (the left side was weathered) and there is part of the neural arch without most of the neural spine . the ceotrum is typically spool-shaped and relatively e longate (length 1 = 120 mm; height h at the extremities = 90 mm; l/h ratio = 1.33), and amphicoe lous with the anterior fac et shallow and the posterior one slightly deeper. these facets are elliptical and slightly greater in width than height. there are moderately developed, separate facets for the chevron on a relatively shallow ventro­ posterior projection of the centrum. pleurocoels, ventral ridges and grooves are absent. there is no true caudal rib or transverse process, only an antero-posteriorly elongate knob (lk in fig. 17) at the base of the neural arch. the latter is placed on the anterior half of the cen­ trum and its base is 48 mm long . the zygapophyses are dalla vecchia: remains of sauropoda (reptilia, saurischia) in the lower cretaceous ... 125 cd cd fi g. 16 mpcmv 15, fragmentary anterior caudal vertebra. views: a) right lateral, b) dorsal, c) posterior. badly and incompletely preserved. the postzygapoph­ ysis is far above the base of the neural canal, the articu­ lar region faces laterally and slightly ventrally. the prezygapophysis is lower on the arch and probably antero-dorsa ll y elongate. only the basal part of thc spine is preserved. a relatively elongate centrum, lacking a caudal rib but possessing a knob at the base of the arch, together with a well developed neural arch, indicate that this is a mid-caudal vertebra (approximately posterior to the 1516 caudal because of the absence of a rib, scc mcin­ tosh,1990b). wnv4 (fig. 18). this vertebra consists of a ncarly complete centrum. it is amphicoelous with shallow articular facets, spool-shaped and more elongated than the centrum of nos ig-i (lcngth = 116 mm, height at the extremi ties:::: 70.5 mm , i/h ratio:::: 1.55). the articu­ lar facets of the centrum are more or less e llipti cal, sl ightly greater in width than in height. pleurocoels, ventral ridges and grooves are absent. the face is for the chevron do not project. the only difference that may be found with the vertebra nos ig-i , if we exclude elon­ gation, is a shorter (40 mm) basal part of the neural arch. only the basal part of both pedicels are preserved; the neural canal is narrow (11 mm minimum width). the neural arch is placed decidedly on the anterior half of the centrum. the resemblance with nos igl and its greater elongation and shorter base of neural arch (per­ haps related to a smaller and lower arch) suggest it is mid-caudal but more distal than the vertebra nos ig-1. comparisons all five caudals present a centrum greater in width than in height , a feature also shared with the cervical mpcm-v2 and the dorsal mpcm-v!. this is not the most common state for sauropods even if it is present, for example, in brachiosaurus brancai (janensch, 19s0) , in the anterior dorsals of diplodo­ cus cm'neg;; (hatcher, 1901), sometimes in the dor­ sals of andesaurus bonaparte & calvo (bona­ parte & coria, 1993), in the dorsals of eucamero­ lusjoxi (blow, 1995). a ball-and-cup articulation is not present, and the centra are amphicoclous or amphiplatyan. therefore titanosauridae sensu salgado et al. (1997) are ex­ cluded, at least for the anterior elements sufficiently complete, since mid-caudals can be amphiplatyan or even gently amphicoelous in primitive forms of the titanosauria. this is the case of malawisaurus jac­ obs, winkler, downs & gomani (amphi coe­ lous; jacobs et ai., 1993), an undetermined genus from argentina (salgado & calvo, 1993), "an de­ saurid" titanosaurs (bonaparte & coria, 1993) and the late maastrichtian magyarosaurus huene (pers. obs.). in the two mid-caudals, and in the most complete anterior caudal, the neural arch is displaced toward the anterior half of the centrum, a feature which was con­ sidered apomorphic for titanosaurids (e.g mcintosh, 1990a), but is considered a synapomorphy of the wider clade titanosatiriformes by salgado et al. (1997). there are no pleurocels, no ventral sulcus (excavation) in the two mid~caudals and in the most complete anteri­ or caudal; the ribs of the three anterior elements are not wing-like, and the centra are always short or moderate­ ly elongated. this excludes the diplodocidae as diag­ nosed by mcintosh (1990a, b). the shape of the centrum of wn-v3 and nos ig-i, and the postero-laterally directed ribs of wn-v3, mpcm-vi4 and mpcm-vis, are more reminiscent of the anterior to mid -tail vertebrae of brachiosaurus brancai (janensch, 19s0). the anterior caudals of camarasaurus are similar to the described an terior ver­ tebrae but do not possess a posteriorly directed rib (ostrom & mcintosh, 1966; mcintosh, i 990a, b). also the position of the neural arch on the centrum, its overall morphology, the shape and position of the postzygapophysis, the orientation of the prezygapoph­ ysis and the shape of the caudal rib correspond to the anterior and mid-caudals of brachiosaurus brancai (janensch, 19s0; mcintosh, 1990b). the comparison with the caudals of this species (janensch, 19s0, pis. ii-iii) and the i/h ratio (0.87) show that the vertebra wn-v3 might be the 6 8 cau126 2cm dal. the mid-caudals nos ig-l and wn-v2 are compa­ rable, considering mainly the elongalion of the centra, respectively, to the 18-20 and 22-25 caudal (janen­ sch, 1950, ibid.). mpcm-v 14 differs from the anterior caudal wn­ v3 because the base of the spine is lower on the arch. isolated caudal neural spines mpcm-v13 (fig. 19), is the basal segment (95 mm tall) of a neural sp ine probably from a small anterior caudal vertebra. it is rectangular in cross section, 30 mm wide in side view and narrow in front (12 mm) and back (15 mm) view. the anterior and posterior sides are wrinkled (rough). there seem to be very short (abou t 30 mm), small supraprczygapophysial laminae, which end just above a short prespinai lamina. there were a geologia croatica 51/2 fig. 17 nos jg-j, mid-caudal verte­ bra. views: a) righl lateral, b) anterior, c) posterior. acronyms: lk = lateral knob at the base of the neural arch. probably corresponding small postzygapophysial lami ­ nae which however, arc badly preserved. on the outer (lateral) sides there is a stronger lamina (lateral spinal lamina, lsl), antero-iaterally directed, which tapers and ends at the upper broken margin of the spine. comparisons it is very different from a brachio­ saurid spi ne. a vaguely similar laminar pattern is pre­ sent in the proximal caudals of apatosaurus (cl ost­ rom & mcintosh, 1966, pi. 35; pers. obs.). mpcm-v9 (fig. 20) . this specimen is the upper portion (90 mm) of a neural spine. it is club-shaped, "triangular" in antcro-posterior view, rectangular in the ventral cross-section of the broken lower part, with flat , smooth outer (lateral) sides and flat and wrinkled (rough) anterior and posterior sides. the tip is rounded, dalla vecchia: remains of sauropoda (reptilia, saurischia) in the lower cretaceous ... 127 .-..... /" ". ~-~;. . 2cm • i -i -'..j a c fig. 18 wn-v4, mid-caudal venebra. views: a) dorsal, b) posterior, c) left lateral. and is formed by the fus ion, represented by a suture, of a scmicylindrical element. the spine was inclined at abou t 15° with respect to the vertical. comparisons it is very similar to the neural spines of the anterior (2?) and mid-caudals (12-13?) of "moro­ saurus grandis" (= camarasaurus grandis) figured in ostrom & mcintosh (1966, pis. 37-38). also the anter ior caudal vertebra of aragosaurus ischiatiells sanz, buscalioni, casanovas & santafe from the hauterivian of spain has a similar neural spine (sanz et ai., 1987). the tip of the spine is generally rectangular in diplodocids. haemapophyses wn-vs (fig. 21). the specimen (175 mm long) is the only nearly complete element among the discovered chevron remains. it is y -shaped, the proximal, articular part is not preserved, the distal shaft is straight and spatulate. comparisons haem apophyses are of poor taxo­ nomic value. only diplodocidae (diplodocus) and some sauropods from china (shunosaurinae) have haem apophyses with a characteristic shape on the mid­ dle segment of the tail but this is not the case in our specimen which is similar to the mid-tail chevrons of both camarasaurus (osborn & mook, 1921) and brachiosaurus (janensch, 1950). no remains indi­ cating the prcsence of thc typical diplodocid mid-caudal chevrons have been collected up to now in the outcrop. appendicular skeleton elements femur nos ig-2 (fig. 22), is the distal, condylar part (not the "proximal quarter" as reported by kozaric et ai., 1996, p. 745) of a quite large right femur, 375 mm long and about 300 mm wide in antero-posterior view. the fragme ntary bone is partly very crushed and weathered. its main recognizable feature is the presence of an undeformed condyle with a lumpy surface which indi ­ cales a well developed cartilaginou s covering. this condyle is asymmetrical in side view (fig. 22b), with an articular surface more developed posteriorly (cf. ostrom & mcintosh, 1966, pis. 71-73), and is slightly splayed outward in front view. the preserved condyle appears to occupy less than half the width of the femur in antero-posterior view and is identifiable as the tibial one (cf. ostrom & mcintosh, 1966, pis. 71-73) . latcral to the condyle (fig. 22a) the bone is vcry crushed in co rrespondence with the sulcus infer­ condiloideus and the fibular condy le, which is nearly completely eroded. comparisons the bone obviously belonged to a large animal, and is here attributed to a sauropod, beca­ use of its size and comparison with the femora illustrat­ ed by gilmore (1936), hatcher ( 190 i), osbo­ rn & mook (1921) and in ostrom & mcintosh (1966, pi s. 71-73). it is very sim ilar to the femora of camarasaurus grandis figured in ostrom & mcin­ tosh ( 1966, pis. 72-73) and camarasaurus in osbo­ rn & mook (1921, figs. 107-j09), but the preserved part has no taxonomic value. tibia mpcmv16 (fig. 23): this is the proximal part of a left tibia. the specimen is 220 mm long. and is dam­ aged in the anterior part, therefore the cnemial crest is partly missing. the latter structure was proportionally rather small (ef. salgado et ai. , 1997, fig. ii). the proximal articular part is spongy in aspect, and there is a moderate caudal projection in thi s region. in the later­ al side there is a marked groove for the accomodation of the proximal part of the fibula; there is also a small and shallow depression on the medial side. the proxi128 a b mal tibia is flallened medioanteriorly-posterolaterally and expanded proximally, and narrows sensibly below the cnemial crest ( the anterolateral-medioposterior width at the base of the cnem ial crest is only 75 mm). this suggests that the tibia under examination had a shaft more slender than those of most sauropod s (ef, mcintosh, 1990, fi gs. 16-17, and salgado et ai., 1997, fig. ii). comparisons diplodocids (diplodocus carnegii and barosaums lenlus in mcintosh, 1990, figs. 1617) have the most slender tibiae among sauropods, probably because of the relative elongation of the hind limbs. the specimen is very similar to the proximal end a b geologia croalica 51/2 0 sprz lsl lsl lsl ® d spzl fig. 19 mpcm-vi 3, fragmentary neural spi ne . views: a) le rt lateral, b) 2cm anterior, c) posterior, d) dorsal. acronyms: l$l= lateral spinal lamc ina, a = anterior, p = posterior, of libia of the latc jurassic "gigantosgllrus megalo­ nyx" (see glut, 1997, p, 439). 4, discussion and conclusions sauropod systematics are chaotic and in a state of flux, as the very different classifications of janen­ sch (1929), mcintosh (1990a, b), bonaparte (1986), upchurch (1994,1997) and salgado et al. (1997) demonstrate. in most classifications the sauropod families are based mainly on just one more or less well known genus and the other members are tenta­ tively included, "weighting" the characters shared with c fig. 20 mpcm-v9, fragmentary neural spine. views: a) anteri­ or, b) posterior, c) right late­ ral . dalla vecchia: remains of sauropoda (repti lia. saurischia) in the lower cretaceous ... 129 fig.21 wn-v5. hacmapophys is. vicws: a) anterior, b) left lateral. those well known forms, in this way haplocalll!to­ sallrus, which is one of the best known sauropods, but lacks the skull and has "mixed" characters, is included in the cetiosauridae by mcintosh (1990b), in the di­ craeosauridac by bonaparte (1986), in the cam a­ rasauridae by upchurch (1994) and finally consid­ ered, in a cladistic analysis, the sister-taxon of the neo­ sauropoda (brachiosauria + diplodocoidea) by upch­ urch (1997). early cretaceous sauropods appear to be wide­ spread and diversified but they are not well known since most species and genera are based on scarce or undi agnostic remai ns . this was underlined by mcin­ tosh (1992) who stated that most sauropod genera "mi ght be termed nomina dubia", "as they can be dis­ tinguished from the 12 well known genera but not from each other because they are based on frag mentary post­ cranial skeletons or teeth" (hunt et ai., 1994, p. 263). therefore comparisons with the istrian remains are in many cases practi cally impossib le . this is clearly ev ident from the taxonomic list of hauterivian bar­ rem ian sauropods after mcintosh ( 1990b; this list of course follows mcin tosh's li nnean class ification) , completed here fo llow ing jacobs et al. (1993), hunt et al. ( 1994), blows ( 1995), and bonapa­ rte (1996). most taxa are based on incomplete, frag­ mentary remains. cetiosauridae (mentioned by hunt et ai. , 1994, but not in mcintosh, 1990b). probably none of these taxa are actually "cetiosaurids". fig. 22 nos ig-2, distal end of a right femur in a) posterior view. b) medial view (tibial condyle), acronyms: tc=tibial condy le. celiosollrlls conybeori melville (wrongly c ited as c. oxoniensis by hunt et ai., 1994) (england, valanginian barremian, vertebrae) . cetiosaurus brevis owen (eng land , valang in ian­ barremian) in lydekker ( 1888) are reported ver­ tebrae, chevrons, metatarsals, phalanges and frag130 o ~:\~/!(t(~ ® c fig.23 mpcm-v16. proximal pari of a left tibia. a) posterolateral view, b) anteromed ial view. c) dislai cross-section. acronyms: cc =cnemial crest, a = anterior. p = posterior. ments of long bones from the wealden and attrib­ utcd to this taxon; no other author mentions them. celiosourus sp. (spain, valanginian barremian). brachiosauridae or nifltopsis liu/kei (eng land , barremian , dorsa l verte­ bra, following blows, 1995). eucamerolus taxi (england , barremian , dorsa l verte­ brae, foll ow ing blows, 1995). pe/o!'osoll!'lis collybea!'e; mantell (england , valan­ ginian, following blows, 1995, only a humerus is cons idered to belong to thi s species). pleurocoelus flal111s marsh (usa, hauteriv ian bar­ remian, isolated remains of morc than 6 individuals, including sku ll elements). p. a/tlls marsh (usa, hauterivian barremian , tibia and fibul a). p. va/dellsis l ydekker (england, valanginian bar­ remian, teeth, dorsal and caudal centra). cr. pleurocoelus sp. (spain , barremian). camarasauridae ararosaurus ischiariclis (spain , earl y barremian, cau­ dal vertebrae, scapul a, fore limb, ischium , pubis). chondrosteosaurus gigas (england, barremian, cervi ­ cal vertebrae; nomen dubium following p. upchu­ rch's pers. comm .). geologia croat ica 5112 titanosauridae unnamed titanosaurid (="titanosa urus" valdensis) (eng land, valanginianbarremian, several cauda l vertebrae). ma/aw;so ll!'iis d ixey; jacobs, winkler, downs & gomani (malawi , early cretaceous, premaxil­ la, dentary teeth , cerv ical, dorsal and caudal verte­ brae , sternal plates, ischium). this taxon could be more recent than the others reported in thi s list (jacobs et ai. , 1993). macrurosclurus semnus seeley (eng land, valangin­ ian, isolated caudal vertebrae). diplodocidac amargasall!'lis cazall; sa lgado & bonaparte (argentina , neocomian , a nearly complete ske le­ lon). incertae sed is mong%sall!'!ls /wp/odoll gilmore (mongolia, berri­ asian albian, teeth , basioccipi tal , 3 cervical verte­ brae). unnamed sauropod (england, hauterivian barremi an, fo re limb, epidermal impress ions). follow ing the list of hunt et al. (1994) from thi s strat igraphic interval there are indete rminate or unde­ scribed " brachiosaurids" also in spa in and ihe usa, dip lodocids in england and argen tina and indetenni ­ nate sauropods in chi na, south korea, mongolia, ja­ pan, niger, franee and england. it can be observed that the record comes mainly from the wea lden of e ng land and there is little infor­ mation about gonci wani an sauropods and none uus i undescribed bones from niger) about northern african wh ich are better known in the albiancenomanian interval. o f the abundant but scatte red englis h remains a plethora of new taxa were created dur ing the 19th cen­ tu ry, and this led to inextricable confusion. following blows (1995) and p. upchurch (pers. eomm.) the wealden sauropod fa una is dom inated by brach io­ saurids whereas camarasaurids are absent. t itanosauria and d ipj odocids are scarcely represented, as seen above. unfortunately a satisfying recent revision of the english matcrial has not been published yct and compari son wi th wea lden sauropods is sti ll at best very difficult. the presencc of "chondrosfeosaunls gigas" both in istria and southern england could have palaeogeo­ graph ic significance but the dip lodocimorph similar to rebbachisaurus is more important under this point of view. this aspec t should be invest igated fu!1her. the study of the described material suggests the fol­ lowing points: dalla vecchia: remains of sauropoda (reptilia, saurischia) in the lower cretaceolls ... 131 i) on the basis of size, at least two "forms" are pre­ sent: a large form (fragments of cervical vertebrae, ?cervical ribs, bony laminae mpcm-v4, part of the neural arch of a dorsal vertebra mpcm-v3, distal part of the femur nos ig-2) and a small one (cervi­ cal vertebra wn-vl, fragmentary cervical vertebra mpcm-v5, posterior cervical centrum mpcm-v2, anterior dorsal vertebra mpcm-vi, all the caudals and thc fragmentary neural spines, the proximal tib­ ia mpcm-v 16). there is too great a difference in size among some remains, and no evidence of immatu rity of small specimens (in all small verte­ brae the neural arch is fused to the corrcs ponding centrum), to support the idea thal all the specimens belong to the same species. even if we consider the islrian sauropods as insular inhabitants with the typ­ ical intraspecific size variability of pleistocenc insu­ lar mammals (kotsakis, 1985) the size differ­ ence is sti ll too great. 2) a new diplodoeimorph sim ilar to rebbachisaurlfs but more primi ti ve because it still retains a hyposphene-hypanthrum, is represented by a poste­ rior dorsal vertebra. 3) the posteri or cerv ical vertebra mpc-v2 is very similar to those of the coeval "chondrosfeosaurus gigas" of england, and in the shape and pleurocoels but not the bone texture, to camarasaurus of north american late jurassic. it is very different from the cervical wn-v i and probably belongs to a different taxon. the latter cervical is most reminescent of the anterior ccrvicals of brachiosaurus brancai. 4) since long cervical ribs arc not known in diplo­ docids (considering mamenchisaurus does not be­ long to them, upchurch, 1997) the fragments of rib shaft here reported, if correct ly identified, belong most probably to a brachiosaurid or a cama­ rasaurid (the state in titanosauria sensu salgado et ai., [997 is not known). 5) all preserved cervical and dorsal vcrtcbral parts (excepted wn-v6) are extremely lightened having a) centra with a "honeycomb"-like, cancellate stru­ cturc, a feature considered by most specialists typi­ cal of the brachiosauridae (scnsu mclntosh, 1990b) or the most inclusive titanosaurifonnes (sensu salgado et ai., 1997), and b) neural arch­ es made by a complex network of thin laminae. 6) the posterior cerv ical mpcm-v2, the anterior dor­ sal mpcm-v [ and all the caudals present elliptical, kidney-shaped or, at leas t, wider than high articular faccts of the centra. 7) the ar ti cul ar facets of the anterior dorsal mpcm­ v i and the posterior ccrvical mpcmv2 have a great difference in s ize which suggests that they belongs to individua ls of rather different size. whether this is due to ontogeny, sexual dimorphism or because they belong to different taxa, is indeter­ minated from the few remains collected . 8) the anterior dorsal mpcm-v i is peculiar in being very small, with the relatively tallest neural arch ever described in a sauropod, cancellate texture of the centrum and with a very developed laminar complex with peculiar st ructures. however, it can­ not be stated with certainty that it does not belong to the same taxon as mpcm-v2, and therefore possi­ bly to "chondrosfeosaurus gigas". this suggests to avoid the creation of a new taxon, pending the exca­ vation of further materia1. 9) thc developed prespi nallamina of mpcm-v3 sug­ gests that it belongs to the titanosauriformes sensll salgado et al. (1997) and most specifically to the advanced titanosauria, or to the diplodocidae. other features exclude the t itanosauria. 10) the anterior and mid-caudals resemble mostly the titanosauriformes sens u salgado et al. (1997) and brachiosaurus brancai in particular, but they are not diplodocid or titanosaurid. 11) surprisingly, the fragmentary caudal neural spine mpcm-v9 is very sim ilar to those of camara­ saurus and aragosallrus. since the other fragmen­ tary caudal neural spi ne mpcm-v 13, which has a relat ively well developed system of lam inae, repre­ sents a different part of the spine, these two speci­ mens could belong to the same taxon. both broken spines are very different from the typically [ow spines of brachiosaurus brancai. hunt et al. (1994) suggested that "iso[ated, but di st inct, postcrania may bc considcred valid type speci­ mens and disassociated specimens from the same bed should be grouped as much as possible. these usually questionable taxonomic procedures are only tolerated in sauropods bccause thesc immcnsc animals are so often represented by such fragmentary or jumbled speci­ mens." (p. 266). the adopt ion here of this procedure is prevented by the presence of individuals with very dif­ fere nt sizes and bones with featu res suggesti ng that they belong to different families (sensu mcintosh, 1990b) (for example, all the caudal s seem to be refer­ able to brachiosaurids while the isolated caudal neural spines are not brachiosaurid spines, cervicals seem to belong to different fami lies, etc.). however, most of the bones seem to come fro m non-titanosauria titanosaurifonnes (sensu salgado et ai., 1997) sauropods. therefore both titanosauriformes, diplodocimor­ pha and, possibly, camarasauridae are present in the site. acknowledgements i thank the gruppo spe[eo[ogico monfa[conese a.d.f. for its collaboration and the collecting of the specimens, dr. giorgio tunis of the dipartimento di scicnze geologiche e ambientali, university of trieste 132 and dr. sandro venturini (ravenna) for their coop­ eration. i thank dr. john mcintosh , dr. paul up­ church and , above all , dr. brian curtice for thc di scussion, adv ice and critical review of this paper. r am indebted to the discoverer of the fossiliferous site. mr. dario boscarolli, for the precious informa­ ti on. i thank dr. alexander kellner and dr. mary dawson for their support respectively at the ameri ­ can museum of natural history of new york city and the ca rnegie museum of pittsburgh. without the help of igor vlahovic, institute of geology, zagreb, thi s pape r could not have been publi shcd and i thank him very much. 1 thank also all the croatian in stitutions which helped me in my study of the material. this work was sponsored by a m.u.r.s.t. grant (40% gi org io tunis) and has been part of my post-doctorate work at the dipartimento di geologia, paleontologia e geofisi­ ca, university of padua. 5. references astibia, h., buffet aut, e., buscalioni, a.d., cappetta, f-i. , corrall, c., estes, r. , gar ­ cia-garm illa, f. , jaeger, j.j., jimenez­ fuentes, e., le loeuff, j., mazin, j.m ., orue-etxerbarria, x., pereda-super­ biola , j. , powell, j-e., rage, j.c., rodri­ guez-lazaro, j. , sanz, j.l. & tong, h. ( 1990): the fo ssil vertebrates from lano (basque country. spain). new evidence on the composit ion and affi nities of the late cretaceous conlinental faunas of europe.tcrra nova, 2, 460-466. blows, w.t. (1995): the early cretaceous brachio­ saurid dinosaurs omitllopsis and eucamerollis from the isle of wi ght, england.palaeontology , 38/1, 187197. bonaparte, j.f. (1986): ti,c carly radi ation and phylogenetic relationships of the jurassic sauropod dinosaurs, based on vcrlcbral anatomy. in: padi ­ an, k. (cd.) : the beginning of the age of dinosaurs. 247-259, berkeley university press. bon aparte, j. f. ( 1996): dinosaurios de am eri ca del sur.musco argentino de ciencias naturales "bernardino rivadavia", buenos aires, 174 p. bonaparte, j.f. & coria, r.a. (1993): un nuevo y gigantcsco saur6podo titanosaurio de la fonnaci6n rio limay (a lbiano-cenomaniano) de la provinc ia dc l ncuq uen, argentina.ameghin iana, 30, 27 1282. boscarolli , d., laprocina, m. , tentor , m., tun is, g. & venturini, s. (1993 ): prima se­ gnalazione di resti di dinosauro nci ealcari haut eri ­ viani di pi attaforma dell ' tstria meridionale (c roa­ zia).natura nascosta, 7, l-20. ca lv o, j.o. & sa lgado, l. (1995): rebbachi­ sourus tessoll ei sp. nov. a new sauropoda from the geologia croalica 51n albian-cenomanian of argentina. new evidence on the origin of the diplodocidae.gaia, ii , 13-33. coria , r.a. (1994): on a monospecific assemblage of sauropod dinosaurs from patagonia: implications for gregariou s behaviour.in: lockley, m.g. , dos santos, v.f. , meyer, c.a. & hunt, a. (eds.) : aspects of sauropod pal eobiology. gaia, 10, 2092 13. curtice, b.d., stadtman, k.l. & curtice, l.j. (1996): a reassessment of ultrasauros macill ­ toshi (jensen, 1985). in: moral es, m. (cd.): the continental jurassic. museum of northern ari­ zona bull. , 60, 87-95. curtice, b.d. & wilhite, d. r. ( 1996): a re-eval­ uation of the dry mesa dinosaur quarry sauropod fauna with a descript ion of juvenile sauropods ele­ ments.in: huffman , a.c. jr. , lund , w.r. & godwin , l.h. (eds.): geo logy and resources of the paradox basin. utah geo log ica l association guidebook, 25, 325-338. dalla vecchia, f.m. (l994 a): i dinosauri dell ' lstria. in: ligabue, g. (cd.): ii tempo dei dino­ sauri. le scienze quadcrni , 76, 82-86. dalla vecchia, f.m. (i 994b): jurassic and creta­ ceous sauropod evidence in the mesozoic carbonate platforms of the southern alps and dinarids.in: lockley, m.g. , dos santos, v.f., meyer, c.a. & hunt, a. (eds.): aspccts of sauropod pale­ obiology. gaia, 10, 65-73. dalla vecchia , f.m. (l997a): terrestrial tctrapod evidence on the norian (late triassic) and creta­ ceolls carbonate platforms of northern adriati c region (italy, slovenia and croatia).in : hanu, c. (ect.): i. int. symp. "mesozoic vertebrate faunas of central europe", proceedings, sarget ia, scr. sci. nat.. xvii, 177-201. dalla vecch ia, f.m. (l997b): dinosau rs in the cretaceous adriatic-dinari c carbonate platform.­ gcoilalia, 1. forum italiano di sc iellze della terra, riassunti , 2, 60-62. dalla vecchia, f.m. (l997c): dinosauri cretacei nell a piattaforma carbonati ca adri atico-dillari ca.­ natura nascosta, 15,22-28. dalla vecchia , f.m. & t arlao, a. (1995): dinosaur evidence in the cretaceous of istria (croa­ tia). in: vlahovic, 1. , velic, 1. & spa rica, m. (eds.): i. hrvatski geoloski kongrcs (first croat­ ian geological congress), zbornik radova (proceed­ ings), 1, 151-154. dalla vecci-lia, f.m. & venturini, s. ( 1995): a theropod (reptilia, dinosauria) footpri nt on a blo­ ck of cretaceous limes tonc at the picr of porto corsini (ravenna, italy).riv. ital. pal. so·at. , 101 / 1,93-98. dalla vecchia: remains o f sauropoda (reptilia , saurischia) in the lower cretaceous ... 133 dalla vecchi a, f.m., tarlao, a. & tunis, g. (1993): theropod (reptilia , dinosauria) footprint s in the albi an (lower cretaceou s) of the quietol mirr.a river mouth (nw 1st ria , croatia) and dino­ sau" population o f istrian region during the creta­ eeous.mem. sci. geol. , 45 , 139148. dinl , m. , tunis, g. & venturini, s. (1998): con­ tinental , bracki sh and marine ca rbo nates from the lower cretaceous of kolone-barbariga (istria, cro­ atia) : stratigraphy, sedimentology and geochemi ­ stry. palaeogeography, palaeoclimatology, palaeo ­ ecology, 140, 245-269. gilmore, c. w. ( 1936): osteology of apatosaurus , with special references to specimcns in the carnegie museum.mem. of the carnegie mus., ii , 175-300. glut, d.f. ( 1997): dinosaurs the encyclopedia. ­ mcfarland & co., jefferson, london, 1076 p. hatcher , i.b. ( 190 1): dip/odocus (marsh), its oste­ o logy, ta'xonomy and probable hab it s, w ith a resto­ ration of the ske leton.mem. of the carnegie mus., i , 1-63. hatc her , j.b. (1903): osteology of hap/ocanlho­ sourus with description of a new species and re­ marks on the probable habits of the sauropoda and the age ancl orig in of the atlonfosaurus beds.mem. of the carnegie mus., 1, 1-63 . hulke, j. w. ( 1879) : note (3 rd) on (eueamerolus hulke) omilhopsis h.g. seeley = bothriospondy/us owen = cholldrosleosaurus magi/us owen.q. 1. geol. soc. london, 35, 752-762. hulke, j.w. (1880): supplementary note on the ver­ tebrae of ornithopsis seeley = eucomerolus hulke.­ q. j. geol. soc. london, 36, 31-35 . hunt, a.p., loc kley , m.g ., lucas, s.g. & meyer , c.a. ( 1994): the global sauropod foss il record. in : lockley, m.g., dos santos, v.f. , meyer, c.a. & hunt, a. (eds.): aspects of sauropod paleobiology. gaia, 10,26 1-279 . jacobs , l.l., winkler , d.a., downs , w.r. & goman!, e.m. (1993): new material of an early cretaceous titanosaurid sauropod dinosaur from malawi. paleontology, 36/3, 523-534. janensc h, w. ( 1929): materia l und formengehalt der sauropoden in der ausbeute de f tendaguru ­ expedition.palaeontographiea, suppl. 7 , 2,1-34. janensch , w. ( 1947) : pneumati zitlit bei wirbeln von sauropod en und anderen sauri schiern. palae­ ontographica, supp!. 7, 3(1), 1-25. ja nensc h, w. ( 1950): dic wirbe lsaule von bra­ chiosaurus broncai.palaeontog raphica, suppl. 7, 3(2),27-93. kotsakis , a. (1985): vertebrati insulari e paleo­ geografia: alcuni esempi. boll. soc. paleonl. ita!. , 24/2-3,225-244. kozaric, z. , spar ica, m. & bajraktarevic, z. ( 1996): histological bone structure of lower cretaceous dinosaurs from southwest istria (croa­ tia).cretaceous research, 17,741-749. lavocat, r.j.m. (1954): sur les dinosa uri ens du continental intercalaire des kern kern de la daoura. comptes rendus 19th. intern. geo!. congr. 1952, part 15/3, 65-68. lockley, m.d. , meyer , c.a., hunt, a.p. & lucas, s.g. (! 994): the distribution of sauropod tracks and trackmakers.in: lockley, m.g. , dos santos, v.f. , meyer, c.a. & hunt, a. (cds.): aspects of sauropod paleob iology. gaia, 10, 233-248 . l ydekker, r. (1 888): catalogue of the foss il repti l­ ia and amphi bia in the british museum. pt. i. con­ taining the orders orn ithosauria, crocodijia, dino­ sauria, squamata, rhynchocephalia , and protero­ sauria.br. mus. nat. hi st. london , 309 p. martin, v. ( 1994): baby sauropods from the sao khua formation (lower cretaceous) in northeast­ ern thai land. in: lockley, m.g., dos san­ tos, v.f., meyer , c.a. & hunt, a. (cds.): asp­ ects of sauropod paleobiology. gaia, 10, 147-1 54. mcintosh , i.s. ( 1990a): spec ies dete rmin ation in sauropod dinosaurs with tentative suggest ions fo r their classifi ca tion. in: carpenter, k. & cur­ rie, p.l. (cds.): dinosaur systematics: perspecti ves and approaches. cambridge university press, new york , 54-69. mcintosh, j.s. (1990b): sauropoda.in: welsh am­ pel, d.b. , dodson, p. & osm6lska, h. (eds.): the dinosauria. u ni versity of ca liforn ia press, 345-40 i. mcintosh, j.s. (1 992) : sauropoda.in: weisham­ pel, d.b. , dodson, p. & osm6lska, h. (cd s.): the dinosauri a (revised first paperback pri nting). university of california press, 345-401. osborn, h.f. (1899): a skeleton of dip/odoeus.­ mem. am. mus. nat. hist., i , 191-214. osborn, h.f. & mook , c.c. (192 1): camara­ saurus , amphicoelias and other sauropods o f cope.­ mcm. am. mus. nat. hist. , n.s. , 3, 247-287. ostrom, j.h. & mcintosh, j.s. (1966): marsh's dinosaurs: the co ll ec tions from como b lu l'f. yale uni v. press , new haven, xvi + 388 p. owen, r. (1875): monographs of the fossil reptilia of the mesozoic formations (pi. ii) bolhriospolldylus, celiosaurlls, omosaurus.paleontogr. soc. mono­ gr. ,29, 15-93. owen, r. (1876): monographs of the fossil repti lia of the mesozoic formations (supp!. vii) crocodi lia (poiki/op/euron) and dinosaufia? (chondrosteo­ sal/l'lis) .paleontogr. soc. monogr. , 30, 1-7. 134 powell, j.e. ( 1986): revision de los titanosauridos de america del sur.unpublished phd thesis, uni­ vcrs idad nacional de tucuman, 340 p. , tucliman. russell, d.a. (1996): isolated dinosaur bone from the middle cretaceous of the tafilalt , morocco.­ bull. natl. hi st. nat., ser. 4°, 18(section c, 2-3), 349-402. russell, d.a. & zheng, z. (1993): a large mam­ cnchi saurid from the juggar basin, xinjiang, peo­ ple's republic of chi na. canad. journ. of earth sciences, 30/1011 , 2082-2095. salgado, l. (1993): comments on chllblllisglirlis i"sill"is del corro (saurischia , sauropoda).­ ameghiniana, 30/3, 265-270. salgado, l. & calvo, 1.0. (1993): report of a sauropod with amphiplatyan mid-caudal vertebrae from the latc cretaceous of neuqucn province (argcntina).ameghiniana, 30/2,215-218. salgado, l. , coria, r.a. & calvo, j.o. (1997): evolution of titanosaurid sauropods. i: phylogenetic analysis bascd on the postcranial evidence.amegh­ iniana, 34/1, 3-32. geologia croatica 51/2 sanz, j.l., buscalioni, a.d., casanovas, m.­ l. & santafe, j.-v. (1987): dinosauri os dcl cretacico inferior de galve (temcl. espana).estu­ dios geol., vol. extraord. galve-trcmp, 45·64. seeley, h.g. (1870): on ornilhopsis, a gigan'ic ani­ mal of the pterodactyl kind from the wea:den.­ annals and magaz ine of nat. hi st. , ser. 4, 5, n9283. tunis, g., sparica, m. & venturini, s. (1994): lower cretaceous from bale (istria, croatia): strati­ graphical, sedimentological and palaeoenvironmen­ tal problems.14th international sed imentological congress, abstracts, s5, 14-15. upchurch, p. (1994): sauropod phylogeny and palaeoecology.in: lockley, m.g., dos san­ tos , v.f., meyer, c.a. & hunt, a. (eds.): aspects of sauropod pa leobiology. gaia, 10,249260. upchurch, p. (1997): a cladist ic analysis of sau ro­ pod dinosaur phylogeny.journ. vert. pal. , 17/3, abstracts, 82a. manuscript received june 29, 1998. revised manuscript accepted november 23, 1998. schlagintweit.indd 27 � ab stra ct the new genus gosavisiphon with the type-species halimeda paucimedullaris schlagintweit & ebli, 1998, tentatively referred to the udoteaceae, is described from the late cretaceous (middle/late cenomanian-santonian) of the branderfl eck formation and the lower gosau subgroup of the northern calcareous alps (austria, germany). it is a plurimillimetric to pluricentimetric marine, hard-substrate dwelling macroalga, with membraneous and partly fused plates and an internal siphonaceous construction but lacking a real medullary zone. although some thallus details are still unknown, gosavisiphon gen. nov. can, from a strictly morphological point of view, directly be compared with the late palaeozoic and upper triassic phylloid algae. gosavisiphon gen. nov. is the fi rst fossil record of a platy siphonal alga in the cretaceous, since the late triassic ivanovia triassica reid. the monotypic taxon is most probably endemic to the northern calcareous alps where it dwelled in protected, terrestrially infl uenced lagoonal environments attaching to hard substrates, (metazoan skeletons, rudistid shells). based on fi ndings of the cylindrical halimeda? aff. johnsoni pal and another taxon described as halimeda sp. with typically fl attened ovate segments, some considerations on the segment-morphological phylogenetic evolution of halimeda lamouroux are provided. halimeda species with discoidal-fl attened segments, that can morphologically be compared with extant species, are not known prior to the turonian. forms possessing cylindrical segments date further back, but can not directly be compared morphologically with modern counterparts, thus placing doubts on the existence of long-lasting methusalemi species by uniting extant and fossil species, as proposed by both botanists and palaeontologists in recent times. keywords: calcareous algae, taxonomy, bryopsidales, halimedaceae, udoteaceae, phylloid algae, phylogeny, upper cretaceous, northern calcareous alps gosavisiphon gen. nov. based on halimeda paucimedullaris schlagintweit & ebli, 1998: a remarkable macroalga (udoteaceae?) from the late cretaceous of the northern calcareous alps, (austria and germany), with affi nites to late palaeozoic and late triassic phylloids � felix schlagintweit lerchenauerstr. 167, d-80935 münchen, germany; (ef.schlagintweit@t-online.de) doi: 10.4154/gc.2010.02 geologia croatica 63/1 27–53 14 figs. 4 tabs. zagreb 2010 geologia croaticageologia croatica geologia croatica 63/1geologia croatica 28 calcareous algae were reported from different localities (e.g. schlagintweit & weidich, 1991; schlagintweit, 1992). the subsequent marine transgression affecting the higher nappe units started during the turonian with the tectonosedimentary cycle of the gosau group that unconformably overlies mainly triassic and jurassic sediments. the alpine gosau group can roughly be subdivided into a lower subgroup with neritic shelf lithologies, and an upper subgroup consisting of deeper water facies (wagreich & faupl, 1994) (figs. 1a–b). from turonian to campanian times, a variegated, mixed siliciclastic-carbonate succession up to more than 2000 metres thick accumulated in a wide 1. introduction in the area of the northern calcareous alps (nca), late jurassic to early cretaceous convergence and nappe stacking were followed by extensional exhumation and subaerial exposure of large parts of the orogen (e.g. ratschbacher et al., 1989). within the northern part of the nca, namely the lechtal nappe, the transgressive sedimentary cycle of the branderfl eck formation started in the lower cenomanian with breccias, conglomerates and orbitolinid sandston es, followed succesively by deeper water lithologies (e.g. gaupp, 1982; weidich, 1984). from turonian marls, olistolites of late cretaceous shallow water limestones with fi gu re 1: a) simplifi ed tectonic map of the eastern alps with the major occurrences of the gosau group (in black) (see wagreich & faupl, 1994). occurrences of calcareous algae described in the present paper (yellow circles; for the distribution of individual taxa see table 1): 1 krumbachalm, brandenberg, tyrol; 2 pletzachalm, tyrol; 3 lattengebirge, salzburg, 4 eisenbach, lake traunsee, upper austria 5 rußbach-pass gschütt-gosau (gosau type-area), 6 weißwasser-unterlausa, lower austria, 7 gams, lower austria. b) lithostratigraphic subdivision of the gosau group of the type area (from wagreich & decker, 2001); asterix marks the position of the fi ndings of gosavisiphon in the area of gosau (locality hofergraben) and pass gschütt-rußbach (locality randobach). c) the village of gosau (780 m altitude) with the dachstein mountains in the background; view towards the south. white arrow points to the hofergraben. a b c felix schlagintweit: gosavisiphon gen. nov. based on halimeda paucimedullaris schlagintweit & ebli, 1998: a remarkable macroalga... geologia croatica 29 discovered in various outcrops of the lower gosau subgroup (fig. 1a, from west to east). the last taxon was also observed in olistolites of the branderfl eck formation. brief informations on geographical setting, microfacies and associations of the algal-bearing samples and stratigraphy are given for each locality. occurrences of the described taxa are summarized in table 1. 2.1. lower gosau subgroup krumbachalm area, brandenberg (locality 1 in fig. 1). the outcropping limestones of the lower gosau subgroup are located at the northern part of the brandenberg gosau, a larger erosional remnant of the gosau group located in tyrol, about 10 km west of wörgl (e.g. fig. 2 in sanders, 1998). microfacies and associations: halimeda? aff. johnsoni pal occurs in bioclastic packstones with corals, rudistids, echinoderms, gastropods, calcareous algae (green algae and red algae), including permocalculus (pyrulites) theresiensteinensis schlagintweit & sanders, and benthic foraminifera (textulariids, and arenaceous encrusting taxa). the krumbachalm area is also the type-locality of acanthochaetetes? krumbachensis (senowbari-daryan et. al., 2004). stratigraphy: upper turonian to coniacian (sanders, 1998 and sanders & pons, 1999 for details). spectrum of terrestrial to neritic palaeoenvironments (lower gosau subgroup; wagreich & faupl, 1994). deposition of the lower gosau subgroup was terminated, from santonian to campanian times, by deepening into bathyal to abyssal depths (wagreich & faupl, 1994). the area around the village of gosau (upper austria) and russbach (salzburg) represents the type locality of the gosau group (fig. 1c). the lithostratigraphic division of the gosau type area still used today is that from weigel (1937) with modifi cations in the last decades (wille-janoscheck, 1966; weiss, 1977; wagreich, 1988; wagreich & decker, 2001) (fig. 1b). the present occurrences (fig. 1a) only represent the erosional remnants of a former wider distribution; preservation is often due to faulting or deposition in synse di mentary active small basins (wagreich & decker, 2001). in the lower gosau subgroup, calcareous algae, mainly dasycladales and halimedaceae, were reported from la go onal limestones, rudistid limestones, and marly limestones, intercalated within marly successions of middle turonian to upper santonian age (e.g. höfling, 1985; schlagintweit, 1991, 1992, 2004; schlagintweit & lobitz er, 2003a). for an inventory of calcareous green algae of the lower gosau subgroup see schlagintweit (2004). the alga halimeda paucimedullaris was described by schlagintweit & ebli (1998) from the pletzachalm section in the sonnwend mountains, tyrol. it also occurs in the lattengebirge (salzburg), weißwasser-unterlausa (lower austria) and pass gschütt-gosau (e.g. schlagintweit & lobitzer, 2003b). new material from the gosau of gams, styria, and the reinvestigation of material already published, especially that from the hofergraben near gosau, resulted in the recognition of morphological and microstructural details that differ suffi ciently from the genus halimeda lamouroux, to warrant establishment of a new genus of the order bryopsidales with the generic name gosavisiphon gen. nov. and the new combination gosavisiphon paucimedullaris (schlagintweit & ebli), described in this paper. 2. sample localities and material studied halimeda sp., halimeda? aff. johnsoni pal and gosavisiphon paucimedullaris (schlagintweit & ebli), were fi gu re 2: stratigraphic distribution of halimeda? johnsoni pal, halimeda sp. and gosavisiphon paucimedullaris (schlagintweit & ebli) in the late cretaceous lower gosau subgroup of the northern calcareous alps supplemented with literature data. it is most likely that halimeda sp. has a larger stratigraphic distribution, than the two middle-late turonian occurrences (see tab. 1). the dashed dark-grey line in halimeda? johnsoni refers to a possible synonymy with boueina pygmaea pia. for comparison, the distribution of the "phylloid algae" and the genus halimeda are indicated (see tab. 3 and details in the text). table 1: summary of the investigated sample localities with respect to the occurrence of the described calcareous algae. species lo ca lit ie s kr um ba ch al m pl et za ch al m la tt en be rg ei se nb ac h ra nd ob ac h h of er gr ab en w ei ßw as se r n ot hkl am m halimeda? aff . johnsoni � halimeda sp. � � gosavisiphon paucimedullaris � � � � � � � geologia croatica 63/1geologia croatica 30 pletzachalm (locality 2 in fig. 1). the pletzachalm section near kramsach (fig. 1 in schlagintweit & ebli, 1998, for exact location), tyrol (austria), was fi rst described lithologically in detail by leiss (1988). the micropalaeontological content (benthic foraminifera, calcareous algae) was studied by schlagintweit (1991, 1992), schla gint weit & ebli (1998) and schlagintweit & sanders (2008), revealing several new taxa, mainly calcareous algae. microfacies and associations: gosavisiphon gen. nov. occurs in marly limestones that are intercalated within a series of marls, with layers of gastropods and coaly plant remains, followed up the section by a rudistid biostrome. gosavisiphon gen. nov. is associated mainly with calca reous algae including dissocladella? pyriformis schlagintweit, neomeris mokragorensis radoičić & schla gintweit, oroseina pletzachensis schlagintweit & ebli, halimeda sp., and benthic foraminifera vidalina hispanica schlumberger (and other miliolids), cuneolinids and tetrataxiella? fl oriformis schlagintweit & sanders. stratigraphy: the age of the series containing gosavisiphon gen. nov. below the rudistid limestones is late turonian. lattengebirge (locality 3 in fig. 1). from this locality, the new taxon was reported for the fi rst time as halimeda sp. by höfling (1985) from the so-called krönner reef. the biocoenosis of the lagoonal "epibenthic udoteaceandasycladacean association" and its adjacent reefal palaeoenvironments were schematically reconstructed by höfling (1985) (see also moussavian et al., 1993). the outcrops occur at the northern side of the lattengebirge, southeast of bayerisch gmain near bad reichenhall (germany); topographic map no. 8243 reichenhall (for exact location see fig. 1 in klinghardt, 1942). microfacies and association: gosavisiphon gen. nov. occurs within marly wackestones referred to a back-reef lagoonal environment (höfling, 1985). stratigraphy: the krönner reef was considered to be santonian in age (klinghardt, 1942; höfling, 1985); strontium isotope data revealed a mid coniacian age (steuber, 2001), which is the same age obtained for the rudistid limestones of weißwasser (see below). eisenbach, lake traunsee (locality 4 in fig. 1). the eisenbach gosau occurrence is located at the eastern side of lake traunsee in the upper austrian salzkammergut, ök 25, sheet 67 grünau im almtal. the samples with gosavisiphon gen. nov. belong to the type material (type locality) of the dasycladale thyrsoporella eisenbachensis (see fig. 1 in schlagintweit & lobitzer, 2003a). microfacies and associations: gosavisiphon nov. gen. was found in marly limestones; wackestones with coaly plant remains, gastropods, ostracods and thyrsoporella eisenbachensis schlagintweit & lobitzer, dissocladella? pyriformis schlagintweit and neomeris mokragorensis radoičić & schlagintweit, and miliolid foraminifera (figs. 8c–d). stratigraphy: middle turonian (based on calcareous nan nofossils). randobach near russbach at pass gschütt (locality 5 in fig. 1). the randobach river is located about 5 km west of the village of gosau. stratigraphy: santonian (kollmann & summesberger, 1982; kollmann, 1985). from this locality gosavisiphon gen. nov. was reported by schlagintweit & ebli (1998: see fig. 2 for exact location). microfacies and associations: brownish marly limestones with the calcareous algae: gosavisiphon gen. nov., oroseina pletzachensis schlagintweit & ebli, neomeris mokragorensis radoicic & schlagintweit, dissocladella? pyriformis schlagintweit, terquemel la? n. sp., and benthic foraminifera nummofallotia cretacea (schlumberger) and vidalina hispanica schlumberger. stratigraphy: upper santonian. hofergraben, gosau (locality 5 in fig. 1). this locality is situated approximately 1 km southeast of gosau, upper austria (ök 1: 50.000, no. 95 st. wolfgang) (see fig. 1c). the material described comes from two small southern tributaries at an altitude of 900 m above sea-level (see fig. 1 in schlagintweit 2004, for exact location). gosavisiphon gen. nov. was already described and illustrated by schlagintweit & lobitzer (2003b) from this locality. the so-called hofergraben marls (hofergraben member of sanders & baron-szabo 2007) belong to the hoch moos formation (see figs. 1b–c). these marls are well-known for their coral fauna, such as the solitary cunnolites (sanders & baron-szabo, 2007). microfacies and associations: gosavisiphon gen. nov. was identifi ed in two different types of siliciclastic-carbonate beds. one is represented by well-sorted arenites with numerous specimens with either chaotic distribution or parallel arrangement; other biotic elements are scarce (rare benthic foraminifera, shell debris) (see schlagintweit & lobitzer 2003a) (fig. 9a). the other type shows low grade sorting with different extraclasts and numerous algal remains including trinocladus tripolitanus pia, neomeris mokragorensis radoičić & schlagintweit, oroseina pletzachensis schlagintweit & ebli and jodotella koradae (dieni, massari & radoičić) (see schlagintweit, 2004) (fig. 11h). stratigraphy: upper santonian (see fig. 2 in sanders & baron-szabo, 2007). weißwasser-unterlaussa (locality 6 in fig. 1). the weißwasser section near unterlaussa, lower austria (topographic map of austria, ök 69, großraming), was studied and illustrated by ruttner & woletz (1955), followed by faupl et al. (1987) and sanders & pons (1999, fig. 17). additional data about the microfauna from this locality were provided by schlagintweit (1992) and schlagintweit & sanders (2008). outcrops from which samples were taken, are located along the forest road to the blaalm (see schlagintweit 1992, fig. 4). felix schlagintweit: gosavisiphon gen. nov. based on halimeda paucimedullaris schlagintweit & ebli, 1998: a remarkable macroalga... geologia croatica 31 stratigraphy: gosavisiphon gen. nov. occurs in a series below rudist limestones (the so-called liegend-serie of ruttner & woletz, 1955) that have been dated biostratigraphically as middle coniacian (e.g. wagreich, 1990) and on the basis of strontium isotope stratigraphy (steuber, 2001). therefore, the material with gosavisiphon gen. nov. may be early coniacian or late turonian. microfacies and associations: marly limestones with cuneolinids, miliolids (vidalina hispanica schlumberger). noth-klamm, gams (locality 7 in fig. 1). the nothklamm profi le is located on ök 101 hiefl au, styria; outcrops are located on the orographic left side of the beginning of the noth-klamm (kollmann 1963, 1965; sanders & pons, 1999, fig. 14). a composite log of the succession of the gosau group of the gams area was presented recently by summesberger et al. (2009) and wagreich et al. (2009). microfacies and associations: the samples with gosavisiphon gen. nov. come from a small interval (less than 1 m thickness), of marly limestones between two hippuritid biostromes (hippurites resectus defrance). brownish siliciclastic-infl uenced packto fl oatstones with stromatoporoids (?cladocoropsis), rudist debris, benthic foraminifera such as vidalina hispanica schlumberger, quinqueloculina sp., and cuneolinids (fig. 8b). calcareous algae are represented by abundant gosavisiphon gen. nov. and some scattered thalli of marinella lugeoni pfender. stratigraphy: upper turonian, with barroisiceras haberfellneri (hauer), compare summesberger & kennedy, 1996) (noth formation of siegl-farkas & wag reich, 1997). 2.2. branderfl eck formation urschlauer achen, ruhpolding. at urschlauer aachen in the bavarian alps, (topographic map of germany no. 8241), an olistostrome is exposed, intercalated in lower to middle turonian marls, (dated by nannoconids and planktonic foraminifera, schlagintweit & weidich, 1991; schlagintweit, 1992). calcareous green algae occur in different olistolites of middle/late cenomanian and/or lower turonian age with heteroporella lepina praturlon, permocalculus sp., harlanjohnsonella annulata elliott, salpingoporella turgida radoicic, trinocladus tripolitanus raineri. stratigraphy: the olistolites in which strongly recrystallized specimens of gosavisiphon nov. gen. were observed are most probably of middle/late cenomanian age. 3. systematics the morphological features of gosavisiphon gen. nov. paucimedullaris (schlagintweit & ebli) comb. nov., originally described as a species of the genus halimeda, necessitates a short introduction to the taxonomy of the siphonal calcareous green algae halimedaceae and udoteaceae, together with short overviews on "fossil versus recent halimeda species" and "phylloid algae", prior to the systematic description of the alga. 3.1. taxonomic overview of fossil siphonal green algae of the udoteaceae and halimedaceae families. the classifi cation of fossil 'halimediform udoteaceans', (flügel, 2004, p. 423) (codiaceae versus udoteaceae versus halimedaceae) is a matter of long lasting discussions (e.g. mu, 1991; dragastan et al., 1997). for a long time the udoteaceae was the accepted family where halimeda and allied taxa have been included. these were placed into the (segmented) codiaceae (e.g. steinmann, 1899; elliott, 1965). the fossil udoteaceae were treated systematically by bassoullet et al. (1983), including not only the mesozoic and cenozoic genera halimeda lamouroux, boueina toula, arabicodium elliott, nipponophycus yabe & toyama and lekhamptonella elliott, but also palaeozoic taxa, for example tauridium guvenc, lancicula maslov, dimorphosiphon hoeg (see boyd, 2007) and some others (e.g. roux, 1985; hubmann, 1990, 1994; hubmann & fenninger, 1997; hubmann, 2000). the work of bassoullet et al. (1983) included only erect segmented taxa, and phylloid algae ascribed to the udo teaceae (see following separate chapter) were excluded. modern algal taxonomy lists the udoteaceae agardh and halimedaceae link as two separate families within the order bryopsidales (former siphonales), and halimeda (with 44 species) as the only genus of the halimedaceae (e.g. algaebase of guiry & guiry, 2009). it is worth mentioning that dragastan et al. (1997, p. 77), included two genera in the family halimedaceae, halimeda and tydemania. for the udoteacae, on the other hand, the algaebase mentions eighteen genera, some of which, however, are considered by some workers to be excluded from this family (e.g. curtis et al., 2008). in order to avoid a misleading mixing of fossil and modern taxa, this compilation should exclude pseudopenicillus dragastan et al., 1997 (late triassic of greece), as it represents an exclusively fossil taxon (dragastan et al., 1997). the remaining seventeen extant genera represent a rather heterogeneous group, concerning the highly diverse thallus architecture and the fact that both calcifying and non-calcifying forms are enclosed. the bauplan is generally tripartite with an anchoring holdfast, a stipe and the blade (e.g. fig. 3a,b). in some udoteacean algae such as udotea or avrainvillea, the length of the bulbous holdfast can equal or even exceed the algal parts that project above the sediment surface (e.g. littler & littler, 1990, 1992). as for representatives of the halimeda, udoteacean taxa may also show different constructional types of the anchoring holdfast as adaptations to different substrates (e.g. littler & littler, 1990: genus udotea; littler & littler, 1992: genus avrainvillea). previously, fi ve taxa were assigned to the halimedaceae (hillis-colinvaux, 1984; hillis, 1991): halimeda lamoroux, penicillus lamarck, rhipocephalus kütz ing, tydemania weber-van bosse and udotea lamouroux. the latter four have now been included in the udoteaceae (e.g. guiry & guiry, 2009). extant genera of the udoteaceae that calcify are penicillus lamarck, rhipidosiphon montagne, rhipocephalus kützing, geologia croatica 63/1geologia croatica 32 tydemania weber-van bosse and udotea lamouroux (figs. 3a,b). calcifi cation differs between genera (and species), varying from light to medium, but in any case to a lesser extent than in the halimeda (e.g. böhm, 1973; liebezeit & dawson, 1982; ries, 2006). for example, within the genus udotea lamouroux we fi nd both calcifi ed (e.g. udotea fl abellum, see fig. 3b), and non-calcifi ed species (e.g. udotea petiolata, see colombo, 1978). as a consequence of this, many present day udoteaceae have no fossil record, because of the lack of thallus calcifi cation. concerning the possibilities of principal descents in the fossil record, the calcifying taxa of the udoteaceae are worth noting. according to verbruggen et al. (2009, fig. 4), udotea should have its fi rst appearance in the late jurassic, rhipidosiphon in the late cretaceous and rhipocephalus during the cenozoic. these assumptions, however, have so far not been validated by the fossil record. kühnel (1932) described udotea adnetensis from the late triassic (rhaetian), commented on its relationship with the genus mitcheldeania johnson & pia (1942) assigned it to the socalled "porostromate algae". diagnosis of both the halimedaceae and udoteaceae families are not common in the palaeontological literature. taking a closer look at the examples provided by dragastan et al. (1997, 2002) (see tab. 2), the non-segmented and non-ramifi ed character of the udoteaceae is worth mentioning. the eponymous genus udotea shows different shap es, e.g. disk-like, fl attened or cyathiform (cup-shaped, udotea cyathiformis), or blade morphology from uncorticated to densely corticated (see monograph of littler & littler, 1990 for details; colombo, 1978). for example, udotea cyathiformis (fig. 3a) posseses a blade without corticated fi laments, and udotea fl abellatum (fig. 3b) a blade corticated by branched fi laments (e.g. littler & littler, 1990). another morphological type of udoteaceae is represented by rhipocephalus commonly known as the pinecone alga with an oval thallus, composed of concentric, tightly packed layered blades. the systematics of the fossil halimedaceae has changed considerably during recent decades. according to dragastan et al. (2002, p. 15), this family should include the following fi ve genera: halimeda lamouroux, juraella bernier, hydracara dragastan, kube & richter, hikorocodium endo and collarecodium brandner & resch. from these, only halimeda has extant representatives. hikorocodium has been shown to represent an inozoid sponge (senowbari-daryan & rigby, 2007), and hydracara has only recently been transfered to the family praecodiaceae dragastan (dragastan, 2008). recently, some more new genera from the late triassic were fi gu re 3: examples of extant (a–b) and palaeozoic (c–d) udoteaceae. a) udotea cyathiformis decaisne, bahamas, blade without corticated fi laments (= ecorticate). b) udotea fl abellum (ellis & solander), florida (from agassiz, 1880, fi gured as u. fl abellata lamouroux), blade corticated by branched fi laments. c) ivanovia tebagaensis torres, permian (redrawn from torres, 1995). d) calcipatera cottonwoodensis torres, west & savin, lower permian of kansas (slightly modifi ed from torres et al., 1992). scale bars 2 cm for a, 1 mm for b, 2 mm for d. a b c d table 2: diagnostic characterization of the two families udoteaceae and halimedaceae (from dragastan et al., 1997, 2002). note that the features refer to fossil taxa whereas in extant forms much more data (e.g. molecular data, morphology of the non-calcifi ed parts) are available for characterization. the stipe and the holdfast of the udoteaceae, that together with the blade are the three basic thallus components are not reported from fossil taxa. order bryopsidales suborder halimedinae halimedaceae calcareous thallus, segmented, ramifi ed, formed by cylindrical, oval, fl abelliform or cuneate in shape, crossed by medullar and cortical siphons having diff erent arrangements from species to species dragastan et al., 1997 thalli segments with multishapes or morphae from cylindrical until disk-like fl attened crossed by multiaxial medullar siphons and cortex with many utricle series from 2 up to 7 dragastan et al., 2002 udoteaceae calcareous thallus (= blade), fl abelliform, nodular, hemispherical, more or less fl attened, without segments. the genera have ecorticate, partial corticate and corticate thalli, the last ones sometimes without medullar and cortical zones dragastan et al., 1997 felix schlagintweit: gosavisiphon gen. nov. based on halimeda paucimedullaris schlagintweit & ebli, 1998: a remarkable macroalga... geologia croatica 33 assigned to the halimedaceae (senowbari-daryan & zamparelli, 2005), altogether showing rather poor preservation of their internal structures, (medullary and cortical siphons) and not facilitating detailed comparisons with modern halimedaceans (tab. 3). except for boueina, that is also known from the late triassic (e.g. flügel, 1975; senowbari-daryan & hamadani, 1999), none of the triassic halimedacean taxa, predominantely reef-dwelling species, survived the reef crisis at the end of the triassic. at present, halimeda is considered the only extant genus of the family halimedaceae link, but there is still no consensus about the fossil members not only of the family halimedaceae, but also the udoteaceae. 3.2. fossil versus recent halimeda species in former times, palaeontologists dealing with halimeda (and allied taxa) were exclusively referring to related fossil taxa, and biologists to extant species when discussing their material. in the last decade researchers of both fi elds tried to combine and synthesize the existing data of fossil and recent taxa, with some controversial results (e.g. dragastan et al., 2002, 2003; dragastan & herbig, 2007; kooistra et al., 2002; verbruggen & kooistra, 2004; verbruggen, 2005; verbruggen et al., 2005, 2009). the complex suprageneric taxonomic history of halimeda has been briefl y summarized in the previous chapter. as palaeontologists can only deal with the dispersed calcifi ed parts of the alga, the understanding of the morphological bauplan of the green alga halimeda is vital before going into detail. recent representatives of halimeda currently number 34 species (e.g. verbruggen & kooistra, 2004) and are composed of fl attened calcifi ed segments, interconnected by non-calcifi ed nodes that haven’t yet been reported from fossil taxa (e.g. hillis-colinvaux, 1980) (figs. 4a,b). towards the bottom, the thallus of halimeda is attached by fi gu re 4: a–b thallus morphology of the genus halimeda lamouroux (from vickers & shaw, 1908). c–h segment morphology of recent (c) and pleistocene (d–h) halimeda species (from dragastan et al., 2002, 2003). i–j transverse sections of boueina (i) and halimeda (j). a) halimeda incrassata (ellis). b) halimeda opuntia (linnaeus). c) deeply trilobed segment of halimeda opuntia f. trilobata (decaisne). d) ovate segment of halimeda copiosa goreau & graham. e) reniform (kidney-shaped) segment of halimeda gracilis harvey ex agardh. f) rounded disc-like segment of halimeda tuna (ellis & solander). g) elliptical-discoid segment of halimeda copiosa goreau & graham. h) triangular rounded segment of halimeda tuna (ellis & solander). i) transverse section of boueina hochstetteri toula, aptian of serbia; intersiphonal spaces in white, representing sparry calcite (from steinmann, 1899). j) transverse section of halimeda cylindracea decaisne, recent, australia; intersiphonal spaces in black (from steinmann, 1899). k) schematic drawing of a longitudinal section of halimeda (without scale), modifi ed after hillis-colinvaux, 1980). a f b g k h c d e j i geologia croatica 63/1geologia croatica 34 means of a holdfast, consisting of branching rhizoids (hillis-colinvaux, 1980; verbruggen & kooistra, 2004). depending on the sediment-type, (hard, sandy, rubble), holdfasts may be felt-like (rock grower), bulbous (sand grower) or composed of only a few branched and loose rhizoids at intervals along the plant (sprawler) (verbruggen, 2005, figs. 7–9). the construction of the holdfast can be considered a habitat strategy (e.g. substrate, water energy) (e.g. hillis-colinvaux, 1977). fossil holdfasts of halimeda have not been reported up to now. based on the different pattern of nodal medullary fi lament arrangement, fi ve sections (= groups of species that refl ect fundamental phylogenetic divergences), are currently recognized (hillis-colinvaux, 1980; verbruggen & kooistra, 2004), an approach impossible to conduct with fossil material. the calcifi ed segments are highly variable in shape (often also within one and the same species), elliptical-discoid, lobed, ovate, rounded, triangular, irregularly quadrangular, reniform to ear-shaped, kidney-shaped, cuneate (e.g. dragastan et al., 2003; verbruggen, 2005, fig. 10–18) (see figs. 4c,h). besides this two-dimensional segment typology, halimeda segments may be distinctly undulated, keeled or ribbed (e.g. verbruggen, 2005, figs. 19–21). in extant halimeda, new segments (or daughter segments) originate terminally at the tips of the older (or mother) segments either in direct continuation of the axis or beside the axis, for instance in cases when two new segments arise, as visible in the specimen of halimeda opuntia shown in figure 4b. this construction is often term ed 'serial-segmented' (details in elliott, 1982). it is noteworthy that there is a terminological dissent between botanists and palaeontologists concerning the numeration of the cortical siphons/utricles. for extant species, the numeration of the utrical series (or orders) starts from the segment surface inwards; for example, the outermost ones are termed primary utricles, and so on (e.g. hillis-colinvaux, 1980; verbruggen, 2005). by describing fossil representatives, the numeration used by the palaeontologists is simply the other way around, with the fi rst cortical siphons arising from the meduallary siphons assigned to as primary or of fi rst order. in the case of the dasycladales, both the phycologists (berger & kaever, 1992) and palaeontologists (e.g. bassoullet et al., 1975; de castro, 1997) use the same numeration for different orders of laterals. if we bear in mind that the reduced nodal region between two subsequent segments is composed only of medullary siphons and the cortical siphons arise from the latter in the segments, the botanical method of numeration is somehow misleading, bearing in mind that the primary utricles are also called peripheral utricles. here, the palaeontological nomenclature is followed. there are contradicting views among phycologists and palaeontologists concerning the fi rst appearance of halimeda as a genus, or more precisely its different phylogenetic lineages. in recent times the so-called molecular clock method has been applied to decipher the phylogeny of halimeda (verbruggen et al., 2009). this method needs fi xed calibration points "where a clade in the tree has a derived character that is unique to that clade and that can be traced in the fossil record. in this case one can infer that (a) the clade must have evolved on the branch of the tree leading to the the base of the clade and (b) that the clade must have evolved prior to its fi rst occurrence in the fossil record" (medlin, 2007, p. 31). according to dragastan et al. (2002) and verbruggen et al. (2009), halimeda should have its fi rst appearance in the permian, based on halimeda soltanensis poncet selected as the only fossil 'halimeda' and used as a calibration point for the phylogenetic calculations and considerations, thus not achieving the 'ideal scenario'...."with multiple fossil calibration points" (verbruggen & theriot, 2008, p. 245). the attribution of this species to the genus halimeda, however, is treated differently among palaeontologists. whereas dragastan et al. (2002) consider it a true halimeda, vachard et al. (2001, p. 382) treat it as a phylloid alga comparable to anchicodium johnson (fig. 5; see section on phylloid algae). this view is followed here, as h.? soltanensis is obviously missing a medullar zone and only has two bilateral cortices. moreover, the morphology of the cortical siphons with their peculiar multiple swelltable 3: extant and fossil genus inventory of the family halimedaceae, modifi ed after dragastan et al. (2002) with supplementary data of senowbari-daryan & zamparelli (2005). hikorocodium included in the family halimedaceae by dragastan et al. (2002) has been shown to represent an inozoid sponge (senowbari-daryan & rigby, 2007, for details) and is therefore excluded from the compilation. dragastan et al. (1997) also included the genus tydemania weber-van bosse as an extant genus of the halimedaceae; more workers, however, included it within the family udoteaceae (e.g. silva et al., 1996). this compilation includes 10 genera (7 when accepting the synonymy of arabicodium, boueina and nipponophycus with halimeda as suggested by dragastan et al., 2002). note that the late palaeozoic eugonophyllum konishi & wray was placed in the family halimedaceae by forsythe et al. (2002), most probably meaning the udoteaceae as accepted here. family halimedaceae link extant fossil halimeda lamouroux, 1812 alpinocodium senowbari-daryan & zamparelli, 2005 (a. fl uegeli senowbari. & zamp., late triassic) arabicodium elliot, 1957 (a. aegagrapiloides elliot, lower cretaceous) brandneria senowbari-daryan & zamparelli, 2005 (b. dolomitica senowbari-daryan et al., middle triassic) boueina toula, 1884 (b. hochstetteri toula, lower cretaceous) calabricodium senowbari-daryan & zamparelli, 2005 (c. irregularum senowbari. & zamp., late triassic) collarecodium brandner & resch, 1980 (b. oenipontanum brandner & resch, middle triassic) egericodium flügel et al., 1992 (e. hungaricum flügel et al., late triassic) juraella bernier, 1984 (j. bifurcata bernier, late jurassic) madonicodium senowbari-daryan & zamparelli, 2005 (m. noricum senowbari. & zamp., late jurassic) nipponophycus yabe & toyama, 1928 (n. ramosus yabe & toyama, late jurassic) felix schlagintweit: gosavisiphon gen. nov. based on halimeda paucimedullaris schlagintweit & ebli, 1998: a remarkable macroalga... geologia croatica 35 ings is different from the infl ated or cylindrical utricle structure of halimeda (e.g. verbruggen, 2005). last but not least, a cylindrical morphology has been assumed by poncet (1989), but not evidenced by illustrations, another characteristic pointing to the phylloid anchicodium (see section on phylloid algae, this work). from the fi ve lineages of halimeda resulting mainly from gene sequencing and differences in the structure of the medullary siphons within the nodal region (e.g. hillis et al., 1998; kooistra et al., 2002), the longest stock is referred to halimeda discoidea by verbruggen et al. (2009, fig. 4). this should date back to the late jurassic, or halimeda cylindracea by dragastan et al. (2002) to the late triassic. some of these obvious controversies are due to different interpretations of segment morphology in fossil taxa and different views concerning the group arabicodium-boueina-halimeda with various stratigraphic ranges. it should be noted that up to now, there has been no description or illustration of a triassic to upper cretaceous halimeda species having fl attened, e.g. discoidal segments (e.g. fig. 4g). according to dragastan & herbig (2007, p. 8), such shapes should occur in latest cretaceous times with halimeda? johnsoni (late cretaceous–paleogene of india, pal 1971), considered a synonym of halimeda opuntia (linnaeus) (miocene–pliocene, fig. 4b). this possible synonymy has already been remarked by dragastan et al. (2002), following the description of pal (1971) that the former should be characterized by leaf-like segments. the only fi guration of halimeda? johnsoni provided by pal (1971), however, shows a longitudinal section of a cylindrical specimen being in accordance with late cretaceous sections of the nca and the internal dinarides (figs. 6a,b). another late cretaceous species with cylindrical segments is halimeda elliotti described by conard & rioult (1977), together with the described species of the genera arabicodium elliott and boueina toula (e.g. bassoullet et al., 1983, tab. 3). the works of dragastan et al. (2002, 2003), a coproduction of palaeontologists and phycologists, provided another grouping into three phyletic lines, 'founded on the segment morphology' as the only criterion. the one with the greatest impact on fossil taxa is the proposed 'fi rst phyletic line' of halimeda cylindracea. with the synonymization of 21 mesozoic and cenozoic taxa, including all late triassic to paleocene species of boueina toula and most of arabicodium elliott, the origin of modern halimeda should date back into the late triassic. boueina hochstetteri was thoroughly investigated using topotype material by steinmann (1899). he stressed a remarkable similarity to halimeda. as one of the main differences steinmann mentions that the cortical siphons of halimeda are swollen at the branching points and that the subsequent higher order siphons are mostly strongly constricted at their bases, features missing in boueina (fig. 4i). curiously, the latter feature was stressed by conard & rioult (1977) as one outstanding feature of halimeda elliotti from the turonian of france. the fact that the turonian halimeda elliotti in turn is put in synonymy with the extant halimeda cylindracea by dragastan et al. (2002), closes the circle again, leaving ample space for interpretations. the general aspect of the cortical zone of h. cylindracea, composed of three to fi ve layers of utricles (hillis-colinvaux, 1980), is a more general feature shared with many other species. the synonymization of the genera boueina toula and arabicodium elliott with halimeda lamouroux (as having priority, see tab. 3) is something that can be seriously discussed. however, the assumption that both type-species (boueina hochstetteri, arabicodium aegagrapiloides), with their totally different aspects of medullary and cortical zones, represent the same species h. cylindracea, seems to be too radical and needs further refi ned investigations. the more so, as halimeda cylindracea does not possess real cylindrical segments with typical circular transverse sections. in dragastan et al. (2002, figs. 3a,b), a fi guration of hillis-colinvaux (1980) is shown with a thallus of halimeda cylindracea whose segments were sectioned at various levels (basal, middle, top). from juvenile to adult stages, the segments become more compressed, but none shows a circular transverse section typical of the late triassic to cretaceous group of halimedacean-like algae (halimeda, boueina, arabicodium). some transverse sections of h. cylindracea tend to be oval (fig. 4j), but typical compressed sections as illustrated by dragastan et al. (2002) were not reported, for instance, from the well-known fossil boueina hochstetteri (fig. 4i). this, however, should be expected in the typical facies with abundant dispersed sega b c figure 5: a–b anchicodium iranicum senowbari-daryan & rashidi, in press, from the permian of iran, note lateral protuberance/swelling (arrow) in (a), and dimorphic cortices in (b) (= inner and outer cortex sensu torres, 2003, fig. 4). c) anchicodium sp. from the permian of south-china (see bucur et al., 2009). the lateral formation of a new plate with reduced width near the bifurcation area and the occurrence of lateral protuberances are comparable to the late cretaceous gosavisiphon (details in the text). geologia croatica 63/1geologia croatica 36 ments. hence, the assumption as far back as the cylindrically shaped species h. cylindracea can be traced, is not only highly controversial but also very speculative and therefore is not accepted here. all taxa with cylindrical segments (independently of their generic position, e.g. boueina, arabicodium, some fossil 'halimeda' species) can not be compared purely morphologically with extant halimeda, and therefore can not be used for tracing its phylogenetic origin. as the segments and some internal features are the only available criteria for comparison of fossil with extant species, present knowledge (or interpretation) has not resulted in a fi nal solution. the fi rst fossil halimeda species that shows segments that can be morphologically directly compared with modern species (see fig. 4) is from the early tertiary with halimeda eocaenica morellet & morellet, a species close to the recent halimeda opuntia (lin na eus) (see bassoullet et al., 1983, p. 490). although nothing is known about the internal structure of halimeda eocaenica (only known as isolated segments), it was determined as synonymous with halimeda opuntia by dragastan et al. (2002) and dragastan & herbig (2007). h. eocaenica has fl attened, shallowly lobed segments (see morellet & morellet, 1940), a morphology previously unknown from cretaceous halimedacean-like algae with cylindrical segments (genera boueina, arabicodium). halimeda sp. described here from the late turonian lower gosau subgroup of the nca can morphologically be compared with h. eocaenica in also having disc-like fl attened segments; a more closer comparison or a transfer of the turonian form to the eocene taxa is not possible as nothing is known about the internal structure of the latter. this is also the reason why a new species with a segment morphology so far unknown figure 6: a–f halimeda? aff . johnsoni pal from the upper turonian-coniacian lower gosau subgroup of the krumbachalm-nachbergalm area (a, c–f) and the santonian of the inner dinarides, serbia (b). a) longitudinal section; sample 20995-3. b) longitudinal section; sample rr 2273. c) slightly oblique longitudinal section; sample 1803. d–e) transverse sections slightly oblique; samples 1803 and 151194/1. f) oblique section, note comparable large medullary and distinctly smaller cortical siphons; sample 1803. scale bars 0.5 mm for a–c, e–f; 0.4 mm for d. a b c d e f felix schlagintweit: gosavisiphon gen. nov. based on halimeda paucimedullaris schlagintweit & ebli, 1998: a remarkable macroalga... geologia croatica 37 from cretaceous representatives of halimeda was not introduced. as a further consequence, the origination of halimeda discoidea during the late jurassic as supposed by verbruggen et al. (2009), is not substantiated by fossil records; fossil halimeda showing disc-like fl attened segments are so far not known prior to the middle turonian (this study). this age of ~ 92 to 93 ma (see gradstein et al., 2004) can be used as a calibration point for a clade of halimeda with ovate fl attened segments, such as halimeda opuntia. according to the molecular clock approach, this morphological characteristic of modern halimeda must have evolved prior to its first fossil appearance, probably around the lower/upper cretaceous boundary. such an interpretation would be in accordance with an assumption already made by elliott (1965) that halimeda sensu stricto evolved in the upper cretaceous. for the molecular node age with the division of halimeda opuntia and halimeda gracilis verbruggen et al. (2009) calculated at 97 ma, this suggests somewhere in the cenomanian. bearing in mind that fossil calibration data are minimum ages for the corresponding lineages, "because newly evolved character.........do not usually fossilize until they become relatively common" (verbruggen and theriot, 2008, p. 245), the observed age for turonian halimeda sp. with discoidal-fl attened segments seems to fi t well with the molecular age. with respect to the incomplete original descriptions and illustrations of the late cretaceous 'halimeda' paucimedullaris and some early cenozoic species of morellet & morellet (1922), kooistra et al. (2002, p. 122) state that these "show similarity to extant groups of species...(of halimeda)...suggesting that the extant diversity consists of living fossils". in conclusion, these resemblances, however, are interpreted by kooistra et al. (2002) as having resulted from iterative convergence therefore representing 'look-alikes'. a completely different view was advanced by hillis (1999, p. 186), another expert in modern halimedacean algae, suggesting that "extant species have appeared relatively recently". although the present state of knowledge on fossil versus extant halimeda species has advanced considerably, the topic is still a challenge for both phycologists and palaeontologists requiring further high quality, combined research for a thorough interpretation of the fossil record as a basic prerequisite when combined analysis of extant and extinct species should be conducted. 3.3. phylloid algae the non-systematic, general term phylloid algae was introduced by pray & wray (1963) for a group of predominantely aragonitic algae, with poorly preserved internal features, that characterized late palaeozoic, (mainly middle carboniferous to early permian) reefal platform margins. they were ascribed mostly to green algae, but some also to red algae (e.g. pray & wray, 1963; konishi & wray, 1967; toomey, 1976; flügel & flügel-kahler, 1980; wahlmann, 2002; gong et al., 2007a, b). phylloid taxa include for instance ivanovia khvorova, 1946 (fig. 3c), anchicodium johnson, 1946, archaeolithophyllum johnson, 1956, calcifolium maslov, 1956, eugonophyllum konishi & wray, 1961, calcipatera torres, west & sawin, 1992, kansaphyllum baars, 1992, or kasimophyllum mamet & vila, 2004. their global dominant role and success could have been favoured by the seawater chemistry, particularly the mg/ca ratio, facilitating aragonite precipitation during that time (ries, 2006). the name 'phylloid algae' comes from the greek word phyllon, meaning leaf. the thallus shape of the phylloid algae is highly variable from simple or undulose plateor leaf-like ('corn fl ake-shaped'), to cyathiform (simple or folded cupshaped, figs. 3c–d) (e.g. torres, 1995, 2003; forsythe et al., 2002; sawin & west, 2005). amongst the forms with cup-shaped thalli, gong et al. (2007a, b) further differentiated between single cup-shaped, cabbage-shaped and clustering cup-shaped forms. some phylloid algae may show a structure of supporting plates similar to a house of cards (e.g. fig. 9a in wahlman, 2002). johnson (1946) and torres & baars (1992) interpret the morphology of anchicodium (see fig. 5) not as being phylloid, but as 'distinctly cylindrical' based on extremely rare, round ed sections. generally, when anchicodium should in fact be cylindrical, circular transverse sections comon, where this alga usually occurs in special types of facies and in great abundances. however, this is not the case. instead, long irregular curved algal thalli can be observed in thin-sections (fig. 5). the illustrated transverse sections display an oblique radial arrangement of cortical siphons that indicate interpretation as sections cutting lateral 'rounded protuberances' that occur at irregular distances at the external side and that were also included by johnson (1946) in the generic diagnosis (see fig. 5a). for the phylloid algae, the presence of an anchoring holdfast, comparable to that of the halimedaceae or udoteaceae, was assumed (torres et al., 1992), but has so far not been discovered fossilized, perhaps as these were not calcifying. the prostrate archaeolithophyllaceae chuvashov in chuvashov et al. (1987) with internal cellular structure and conceptacles, (red algal affi nities) are commonly separated from the phylloid algae with green algal characteristics, as the latter may result from the complete sparitization of the former (vachard et al., 2001, p. 389, fig. 15). other phylloid taxa were included in the family calcifoliaceae termier, termier & vachard (see vachard & cózar, 2006). some of the aforementioned taxa (e.g. ivanovia) have directly been compared with modern halimedacean algae (e.g. genus halimeda) (e.g. harbaugh, 1960; crowley, 1969; kirkland et al., 1993). for example, eugonophyllum is ascribed to the family udoteaceae based on exceptionally well preserved specimens with primary aragonitic skeletons (kirkland et al., 1993). based on the conclusion of hillis-colinvaux (1984), that the family name halimedaceae should have priority over udoteaceae, the genus eugonophyllum was placed in the former by forsythe et al. (2002). it should be placed in the udoteaceae as the present day halimedaceae are monogeneric (genus halimeda) (see tabs. 2–3). for those taxa that were referred to or compared with udoteacean/halimedacean geologia croatica 63/1geologia croatica 38 algae, the absence of a clearly delimited medullary zone (e.g. anchicodium, fig. 5) or its reduced size in some genera is striking; in these cases, a bilateral cortex, sometimes dimorphic (see fig. 5b), may arise from the median central part of the alga. in fact, there are superfi cial morphological resemblances, for instance between late palaeozoic cup-shap ed phylloid algae (torres, 1995, 1997; torres et al., 1992) and extant udoteaceans such as udotea cyathiformis (see fig. 3b, d–e). a further cross-link between phylloid and halimedacean algae is represented by the occurrence of mound structures within both groups (e.g. braga et al., 1996, 'segment reefs'; gong et al., 2007 a, b; grammer & ritter, 2008). alternatively, late palaeozoic archaeolithophyllacean mounds (e.g. genus archaeolithophyllum), built by an open framework were compared with holocene deeper water mesophyllum-dominated boundstones (davies et al., 2004) or with encrusting peyssonneliaceans (james et al., 1988). all examples mentioned clearly demonstrate that the term 'phylloid' does not imply either a particular growth habit, gross morphology or any taxonomic position, and is used as an algal waste-paper basket. phylloid algae have a discontinuous stratigraphic record with a main acme in the late carboniferous-early, p.p. late permian. there is a reappearance in the late triassic (norian) after a gap of about 35 to 40 ma with the single taxon ivanovia triassica (reid, 1986; torres, 2003), one survivor of the mass extinction at the end of the permian (e.g. payne et al., 2004; jablonski, 2005). again after a considerable stratigraphic gap of more than 100 ma, another taxon with comparable morphology appears in the late cretaceous with gosavisiphon gen. nov. a phylloid alga was described by dragastan et al. (1993) from the bathonian of india; the illustrations, however, do not facilitate further discussion. the obvious absence of this peculiar algal morphology in posttriassic times and the reasons for its sudden reappearance in the late cretaceous are unknown. perhaps, this morphology arose independently two or more times. 4. palaeontological descriptions division chlorophyta pascher order bryopsidales schaffner family halimedaceae link halimeda? aff . johnsoni pal, 1971 figs. 6a–f 1971 halimeda johnsoni, n. sp. – pal, pl. 1, fi g. 1 description: small, cylindrical segments (length: 1.35– 1.40 mm, diameter: 0.2–0.5 mm) with broad-rounded ends, made up of sparry calcite; calcifi cation comprises both medullary and cortical zone. constrictions of the segments are indicated. medullary siphons large (diameter: 0.024–0.045 mm); cortex consists of fi ner, three (?four) loosely disposed utricle series (diameter: 0.016–0.035 mm), resulting in comparable large intersiphonal spaces. the ratio of segment width to length is 0.29 to 0.31 (pal, 1971: 0.240 to 0.375). comparisons and discussion: in the original description, halimeda? johnsoni was only illustrated by one longitudinal section, showing a striking analogy to specimens shown in figs. 6a–b. as no holotype was indicated in the original paper, this specimen fi gured on plate 1 fi gure 1 by pal (1971) is designated here as a lectotype. also the range of the dimensions of the alpine specimens is comparable to those given by pal (1971) for fi ve segments. there are some minor variances, e.g. the diameter of segments may also be smaller than data from pal (1971, d: 0.48–0.52 mm). from the specimen illustrated by pal (1971), a leaf-like morphology was assumed (see dragastan et al., 2002; dragastan & herbig, 2007) and the species was synonymized with the extant halimeda opuntia. the specimens from the lower gosau subgroup, however, clearly show circular cross-sections as expected in cylindrical segments. halimeda? johnsoni was described from the maastrichtian-palaeocene of india, the specimens from the lower gosau subgroup are of late turonian-coniacian age. boueina pygmaea (pia, 1936, cenomanianturonian of morocco), arabicodium tibeticum (yu jing, 1976, paleocene-early eocene of tibet) are comparable to halimeda? johnsoni as is halimeda nana (pia, 1932, paleocene of morocco) to some lesser extent. the four taxa (including h.? johnsoni) need systematic reconsideration and reinvestigation for the evaluation of possible synonymies. note that pia (1936, p. 13) tentatively referred boueina pygmaea to the genus boueina rather than halimeda 'as no bifurcation of the thallus was observed', a non-diagnostic feature, the more so when only dealing with some thin -sections. last but not least, halimeda? aff. johnsoni pal appears in bioclastic packstones with corals, and rudists, and sponges, indicating an open marine paleoenvironment, whereas the other two taxa halimeda sp. and gosavisiphon gen. nov. paucimedullaris (schlagintweit & ebli) comb. nov. described from the lower gosau subgroup occur in lagoonal wacketo packstones with totally different algal fl ora and microfauna. another observation illustrated here in fig. 6b is from the santonian type-locality of neomeris (drimella) jerinae in the internal dinarides of serbia (see radoičić, 1984). halimeda sp. fig. 7 description: weakly calcifi ed, fl attened, disc-like to broad ovate segment sections (slightly broader than high) of light brownish colour. typically, only the segment periphery (thick ness: ~ 0.08 to 0.2 mm) with up to three (? four) orders of tiny, cylindrical to cylindroconical cortical siphons is preserved; the large central part that hosted the medullar zone and the innnermost siphons is represented by a sedimentfi lled cavity. therefore, nothing can be said about the internal structure. transverse sections sometimes are bent and display varying thicknesses. for dimensions see table 4. comparisons and discussion: at the pletzachalm locality halimeda sp. and gosavisiphon gen. nov. paucimedullaris (schlagintweit & ebli) comb. nov. co-occur. due to external morphology, degree of calcifi cation and other features, both can easily be distinguished. the ovate segment morphology was previously unknown from the cretaceous felix schlagintweit: gosavisiphon gen. nov. based on halimeda paucimedullaris schlagintweit & ebli, 1998: a remarkable macroalga... geologia croatica 39 (and older) halimeda species, so these segments could belong to a new species. a comparable segment morphology is known from halimeda eocaenica morellet & morellet; the dimensions of the cretaceous specimens are smaller, but this feature is not diagnostic as variable sizes and also segment forms may occur in different parts of a halimeda thallus (see figs. 4a–b). the eocene taxon is only known from isolated segments; internal structures are unknown. isolated segments of h. eocaenica were also collected by genot (1985a, p. 210) but not studied by means of oriented sections, as these were recrystallized affecting both medullary and cortical siphons. thus, we can not exclude but also not validate that the turonian specimens belong to halimeda eocaenica morellet & morellet. therefore, synonymization of the fossil halimeda eocaenica with the recent halimeda opuntia by dragastan & herbig (2007, p. 8), on the feature of comparable segment shapes alone, seems premature as the "the cortical system with variously shaped utricle series remains the primary key for identifi cation of fossil material and corresponding extant material" (op. cit., p. 15). ? family udoteaceae agardh (remark: refering to silva, 1980) remark: notwithstanding and obviously unaware of the common knowledge on botanical taxonomy, the udoteaceae were introduced as a new family name with diagnosis by nizamuddin (1963) almost 80 years after the establishfigure 7: a–c segment sections (outlined in red) and morphology of halimeda sp., late turonian of pletzachalm. a–b transverse sections, sample pletz 7 and sample bsp 5211a-93. c longitudinal section in the plane of compression, sample pletz 7. note the totally decalcifi ed medullary zone also aff ecting the innermost cortical utricles in all three specimens. above right: schematic segment outline from a; below: schematic segment outline from c. h = segment height, w = segment width, t = segment thickness. a b c table 4: segment dimensions (in mm) of halimeda sp., upper turonian of pletzachalm (samples 5211a 93 and pletz 7) and eisenbach (sample eb 9b). h = segment height, w = segment width, t = segment thickness. w t h sample – 0.64 – 5211a93 – 0.40 – 2.10 0.40 – pletz 7 2.40 – 1.90 1.05 0.35 – eb-9b geologia croatica 63/1geologia croatica 40 ment of the family. gosavisiphon gen. nov. surely belongs to the green alga order bryopsidales, however, the family rank is uncertain. refering to fossil udoteaceans as segmented or non-segmented algae with an internal unpartitioned siphonal construction, gosavisiphon gen. nov. is for reasons of pragmatism and taxonomic simplicity also placed in this family. the question of whether it belongs to the halimedaceae can definitely be excluded (see tab. 2). perhaps, the combination of the external and internal morphology necessitates the establishment of a new family with at present only one genus. gosavisiphon gen. nov. origin of the name: the genus name refers to the latinized name of gosau, named after the village of gosau, lower austria (see fig. 1c), combined with the siphonous inner structure. type species: halimeda paucimedullaris schlagintweit & ebli, 1998. diagnosis: plurimillimetric to pluricentimetric, irregularly curved and twisted, non-segmented and non-branching plates, occasionally with irregularly distributed swellings; distal margins slightly thickened, rounded. basal part stratose, attaching to hard substrates by means of fl at crusts, ocassionally with small rhizoidal outgrowths. cortication comprises both the basal and erect part. plates partly fused laterally showing multilateral cortices separated by a thin sparitic line (?extracellular cement). the internal non-septate siphonal construction consists of an often sparitic median line (?reduced medullary zone), from which bilateral cortices originate. cortices with 3–5 layers of utricles mostly dichotomously, sometimes also trichtomously branched, and set at right angles to slightly oblique to the median plane; internal siphons long, cylindrical to cylindroconical occasionally with a moderate terminal swelling, peripheral siphons rather short. breakage of thallus preferentially along the median plane leading to the formation of fragments with unilateral cortices. calcifi cation well developed; siphons fi lled with blocky calcite, intersiphonal spaces of light to dark brownish appearance. reproductive structures and exact three-dimensional thallus architecture unknown. composition: so far monospecifi c. comparisons and discussion: the taxon in question was originally described as a species of the genus halimeda lamouroux by schlagintweit & ebli (1998), characterized above all by its reduced medullary zone (as refl ected in the species name) and having cylindrical segments. as discussed below, the thallus organization of the gosauian taxon is on the whole completely different from halimeda. in the original description of halimeda paucimedullaris, the segment morphology was erroneously reported as being cylindrical because of the supposedly fi ngershaped sections with parallel outer margins. moreover, the original description was based on comparable short thallus parts only; the wavy plurimillimetric to pluricentrimetric specimens were only discovered afterwards (schlagintweit & lobitzer, 2003). already dragastan et al. (2002, p. 16) quoted that the segments of halimeda paucimedullaris are not, as erroneously indicated, cylindrical, but fl attened, most probable nearly discoidal. dragastan et al. (2002, p. 17) claim the species validity "with distinct structure and morphology that cannot be referred to any of the recent species of the genus" (= halimeda). sections of very long (> 2 cm length) and thin (~ 0.4 to 0.5 mm) specimens led us to conclude that these are not individual segments and parts of a segmented alga like halimeda (see figs. 4a–b). the general shape and their wavy outline in cross sections are not compatible to the segment sizes and morphology (including also the ratio length/width) of any known halimeda, both extant and extinct (figs. 4c–h), and there are several indications that in gosavisiphon gen. nov. instead we are dealing with plate-like phylloids (or membranes): (a) the specimen shown on fig. 10a, represents a section with a more or less constant thickness (~0.4 to 0.5 mm) over a length of more than 2 centimetres. this specimen is the only one observed in this thin-section and the probability that it is directly cut exactly in the middle of a cylinder along its total length is improbable (compare with the same consideration for anchicodium, in the section on phylloid algae, fig. 5). this also accounts for the large specimens shown in figs. 8a and 9d, or very long specimens, or variously bent specimens. if a bent specimen of a small cylinder is cut in random thin-sections, we would fi nd interruptions in the longitudinal section with tapering on both sides of the part that bends away from the cutting plane. (b) in all thin-sections studied, we never observed a rounded/circular transverse section with a central medulla and radially arranged cortical fi laments provided by cylindrical segments. the sometimes assymetric appearance of the cortices, i.e. different thicknesses on oppsite sides in sections, suggests a phylloid of reduced width comparable to a belt or plate. thus, in oblique longitudinal sections the median plane is not centreed as would be expected when referring to a cylindrical morphology. furthermore, several fl attenedovoid transverse sections recovered, support the inferred morphology (figs. 14k–m). (c) the characteristic debris of gosavisiphon is composed of fragments consisting only of unilateral cortices. this type can be explained by the less well calcifi ed median, facilitating preferential damage/breakage along this plane of the algal phylloids. apart from this, these fragments are also formed by the lateral formation of new phylloids and their easy disintegration (see fig. 14, for explanation). (e) the wavy segments can morphologically directly be compared with the so-called phylloid algae. besides the general morphology being totally different from halimeda, the internal structure also shows differences. first of all, the often total lack of a central medullary zone is striking, whereas in halimeda this zone can (differing from one species to the other) make up more than 3/4 of the segment diameter, consisting of multiple longitudinally arranged medullary fi laments. only in halimeda cryptica colinvaux & graham and halimeda pygmaea verbrugfelix schlagintweit: gosavisiphon gen. nov. based on halimeda paucimedullaris schlagintweit & ebli, 1998: a remarkable macroalga... geologia croatica 41 gen, littler & littler, is the medulla composed of a single fi lament (colinvaux & graham, 1964; verbruggen et al., 2007). finally, halimeda is anchored in the sediment by means of a rhizoidal holdfast (fig. 4a); gosavisiphon in contrast represents an alga with a fl at prostrate thallus portion with rhizoidal outgrowths fi xed to biogenic hard substrates. gosavisiphon paucimedullaris (schlagintweit & ebli, 1998) comb. nov. figs. 8–12, 14e–f, k–m 1985 halimeda sp. – höfling, pl. 11, fi gs. 7–9 1993 halimeda sp. – moussavian, höfling & herm, pl. 4, fi g. 3 figure 8: microfacies with gosavisiphon paucimedullaris (schlagintweit & ebli) from the lower gosau subgroup of the northern calcareous alps. a) left: mixed siliciclastic-carbonatic tempestitic layers intercalated in the hofergraben marls with abundant, chaotic oriented algal plates appearing as dark, brownish curves forming a fl oatstone facies. locality hofergraben, east of the village of gosau; stratigraphy upper santonian, sample hg 3d. right: same fi guration, specimens of gosavisiphon paucimedullaris (schlagintweit & ebli) are coloured in orange. b) left: brownish marly limestone (bioclastic packstone to fl oatstone) with one curved specimen. noth-klamm, gosau of gams, upper turonian. right: same fi gured specimen of gosavisiphon paucimedullaris (schlagintweit & ebli) coloured in orange. c) wacketo fl oatstone with branching thallus of the dasycladale thyrsoporella eisenbachensis schlagintweit & lobitzer (t) and plate of gosavisiphon (g). eisenbach locality; stratigraphy middle turonian, sample eb-9b. d) close-up view of c showing plate of gosavisiphon. a b c d geologia croatica 63/1geologia croatica 42 figure 9: gosavisiphon paucimedullaris (schlagintweit & ebli) from the upper santonian hofergraben marls, mixed siliciclastic-carbonatic tempestite layers (a–d) and the late turonian lower gosau subgroup of the nothklamm, gams (e–f). a) four plates in parallel arrangement/orientation, sample hg-3b. b) specimen showing a sparitic, probably monosiphonal medullary zone from which in a perpendicular manner cortical siphons of several orders originate, sample hg-3b. c) specimen with extremely reduced to lacking medullary zone; note elongated and distally widening primary siphons (utricles), sample hg-3d. d) long algal plate with fused plate parallely at longer distance (above) showing a little darker colour. e) long, slightly undulating algal plate with unilateral cortex; note sparitic central line, sample hg-3d. f) detailed view from e showing tapering and change of orientation of the cortex. a b c d e f felix schlagintweit: gosavisiphon gen. nov. based on halimeda paucimedullaris schlagintweit & ebli, 1998: a remarkable macroalga... geologia croatica 43 1998 halimeda paucimedullaris n. sp. – schlagintweit & ebli, pl. 1, fi gs. 1–3, 6; pl. 2, fi gs. 1–2 2003b halimeda paucimedullaris schlagintweit & ebli – schlagintweit & lobitzer, pl. 1, fi gs. 1–3 2004 halimeda paucimedullaris schlagintweit & ebli – schlagintweit, pl. 1, fi g. 3 diagnosis: see diagnosis of the monotypic genus. description: the alga is well calcifi ed with sparite fi lled siphons and an intersiphonal part showing a light-brownish, more seldom slightly yellowish appearance. the thallus is differentiated into a basal prostrate portion and an erect part. it was found encrusting biogenic substrates such as metazoan skeletons (e.g. stromatoporoids) or fragments of rudistid shells (fig. 12). the crustose part (thicknesses mostly from < 0.1 mm to 0.4 mm) directly follows the substrate surface, often for lengths of several millimetres; in this connection, small rhizoidal outgrowths of the crusts may enter existing hollows (observed up to ~ 0.5 mm in depth), such as skeletal pores. depending on the geometry of the substrate pores, these rhizoidal outgrowths may be straight or strongly bent in order to completely fi ll the former. smaller shell debris can also become totally encrusted on all sides. these examples were observed without the erect part; it must remain open, whether this is due to breakage or it being a special morphotype lacking an erect part. in many cases, the crusts are diagenetically obliterated appearing as a dark brownish mass with poorly preserved internal features; a central sparitic line and fi ne cortical siphons, however, are discernible. within the crusts, the sparitic line, interpreted as a strongly reduced medullary zone (?monosiphonal), can be either at the base just between the substrate and the algae (?acting as cement) or more or less in the central part. in the fi rst case, only a simple monolateral cortex is present with siphons perpendicular to the substrate and dividing in growth direction. alternatively, a cortex, developed on both sides (bilateral cortices) is present. commonly, the algal thallus becomes erect, bending away from the substrate mostly gradually with low inclination. then another plate may attach that grows in the opposite direction; the length of the attaching plane between the two plates is variable; in any case a thin sparitic crust interpreted as extracellular cement is developed. often ends or margins of the plates seem to be broken leaving only remnants with unilateral cortices, which together with the fact that the observed plate arrangements seem to be somehow incomplete (missing of whole attaching plates), means that the three-dimensional thallus architecture is unclear. more rarely, individual plates may also bend away from the substrate in a perpendicular manner. the plates (or phylloids, or thallus membrane) maybe more or less straight (at least along longer portions, fig. 10a) but more often irregularly bent also showing constricted and swollen areas (e.g. figs. 10g–j). the plates vary in thickness from 0.2 mm to 0.68 mm averaging 0.4 mm (n = 30); the greatest observed length is 2.1 centimetres (fig. 10a). at the eisenbach locality, very small plates with thicknesses around 0.1 mm were observed, that somehow due to their microfacies, can be interpreted as phenotypic variations (figs. 8c–d). anyway, the total biometric ranges can be regarded as certainly obscured by breakage and diagenetic processes (e.g. compression). normally, a central sparitic line, that could be interpreted as a monosiphonal medulla, is present. in parts where new plates are attached, this zone moves toward the margin and fi nally forms the outer zone of the one plate and concurrently acts as the base of the attaching plate where a monosiphonal cortex develops (figs. 11a–c). in these portions a multilateral (or tri-lateral) cortex is present (see fig. 14 for explanation), meaning a bilateral cortex from the attached plate and a monolateral cortex from the fusing plate, being in contuity with the siphonal branching direction, is visible in thin-sections. remarks on calcifi cation: in the investigated thin-sections, not only gosavisiphon but also the accompanying dasycladalean algae namely neomeris mokragorensis radoićič & schlagintweit, or in the tempestite layers of the hofergraben marls also trinocladus tripolitanus raineri and jodotella koradae (dieni, massari & radoićič) show the same characteristic light brownish appearance (see schlagintweit, 2004, pl. 1) (fig. 13). this so-called 'brown calcifi cation'may represent either primary calcite or aragonitic relicts (see discussion in masse & bucur, 2002, p. 160). recent dasycladalean algae develop essentially aragonitic skeletons (e.g. berger & kaever, 1992); whereas in fossil species the original crystalline phase and microstructure have been destroyed by diagenetic recrystallization (e.g. overview in de castro, 1997, p. 165). well preserved isolated dasycladalean thalli that have retained their original aragonite were reported by génot (1980, 1985a, b) from the tertiary of the paris basin. exceptions with skeletons of radial fi brous (?calcitic) crystals or dark micritic skeletons may also exist (e.g. conrad & varol, 1990). hence, for the time being, a relict aragonitic preservation is put up for discussion. the reason for the diagenetic history allowing this peculiar kind of brownish preservation of originally aragonitic algae in the late cretaceous lower subgroup is not known; perhaps factors including continental infl uences and fl uctuations in the salinity and mg/ca ratio could have played a role (e.g., ries, 2006). it is noteworthy, that miocene to pleistocene representatives of halimeda with aragonitic skeletons also show a light to dark brownish appearance in thin-sections (see dragastan et al., 2002). older representatives of halimeda, however, show recrystallized, sparitized segments (e.g. bassoullet et al., 1983), like the majority of the skeletons of fossil dasycladaleans. this should be highlighted with thick and dark-grey letters same manner as on page 43 remarks on calcifi cation: from all observations made in the investigated thin-sections from different localities, a hypothetical reconstruction of the thallus of gosavisiphon, with interpretation of variously oriented sections, was made (fig. 14, except b). it shows that gosavisiphon was an epilithic alga growing on hard substrates such as metazoan skeletons or rudistid shells, occurring in geologia croatica 63/1geologia croatica 44 figure 10: gosavisiphon paucimedullaris (schlagintweit & ebli) from the randobach, pass gschütt area, upper santonian (a–e) and the upper turonian of noth-klamm, gams (f–j). a) straight to slightly undulating thallus of more or less constant thickness with rounded tip (see detail b), central sparitic line (monosiphonal medulla) in the centr (c) or excentric, random (d) and beginning of breakage at the opposite side (see detail e); total length of specimen is 2.1 cm. sample 1791. g–j curved plates; note varying thickness in (g) and (j), lateral protuberance (arrows in i) with three-layer cortices in the area of a lateral protuberance (close up view of protuberance is shown in (f); plate outline in red). median plane in (i) is marked in yellow. a b b c c d e f d g h j i felix schlagintweit: gosavisiphon gen. nov. based on halimeda paucimedullaris schlagintweit & ebli, 1998: a remarkable macroalga... geologia croatica 45 figure 11: gosavisiphon paucimedullaris (schlagintweit & ebli). a–c detailed views of laterally fused plates with three(a, c) and two-layered cortices; note the same orientation of the cortices in (b). d, f) portion of a plate with excentric position of monosiphonal medulla marked in orange, plate outline in red (f, detailed view of d three orders of siphons). e, g) plate with two swelings (arrows) separated by a constricted portion (g, detailed view of e, white rectangle). h) mixed siliciclastic-carbonatic microfacies of the hofergraben tempestite layers with extraclasts (dark), dispersed shell fragments and a fragment of gosavisiphon gen. nov. in the centre. i) close up view of (h) (black rectangle) showing unilateral cortex with comparable long cylindroconical siphons of diff erent orders (1, 2). j) two fused fragments showing opposite orientation of cortices. a b c d e f g h i j geologia croatica 63/1geologia croatica 46 soft-bottom substrates, differentiated into a basal prostrate and an erect main part (fig. 14a). the basal attached part directly follows the contours of the substrate surface, also infi lling small depressions of the latter. in the prostrate part of the thallus, a thin sparitic layer between the unilateral cortex, with siphons dividing in direction away from the subfigure 12: basal encrusting part of gosavisiphon paucimedullaris (schlagintweit & ebli), upper turonian, noth-klamm, gosau of gams (a–e) and upper turonian of pletzachalm (f–g). a crust upon stromatoporoid skeleton, internal siphonal structure barely recognizable. b crust fragment fi xed to a cavity within the basal substrate. c specimen fi xed to a stromatoporoid skeleton (dashed line); solid line: upper crust surface. note the infi lling of the intraskeletal pores and the erect bending away from the substrate; crust-sediment boundary solid line, rhizoidal crust outgrowths within the skeletal pores in dashed line. d specimen fl at encrusting a rudistid shell. e crust fragment fi xed to substrate; internal siphonal structure well recognizable. f–g crust fragments fi xed to pelecypod shells. a b c d e f g felix schlagintweit: gosavisiphon gen. nov. based on halimeda paucimedullaris schlagintweit & ebli, 1998: a remarkable macroalga... geologia croatica 47 strate, can be observed and interpreted either as monosiphonal medulla or extracellular cement (fig. 14d). then, the alga bends away from the substrate either continuously at a low angle or more abrupt forming the erect part where new fused plates, separated by a thin sparitic line or zone and interpreted as extracellar cement/mucilage, occur. within these fused parts a tri-lateral cortex (fig. 4g) occurs composed of the unilateral cortex of the basal attached part and the bilateral cortex of the newly formed plate. breakage and displacement of the algal plates occurred preferentially along these attachment zones commonly producing fragments with unilateral cortices of typical cylindrical to cylindroconical, long and parallel arranged siphons of several orders and reduced intersiphonal spaces (fig. 14e). an equivalent thin sparitic zone separating adjacent and laterally fused plates also occurs in the central part of the plates (?monosiphonal medulla?), from which cortical siphons arise in both directions. depending on the plane of section, the thin central sparitic zone doesn’t always appear centreed (fig. 14j), is also observable in the parts where plates fuse, and can occupy a random position. the plates are bent along the longitudinal axis and irregularly twisted in the plane of compression (fig. 14h). as the plates may reach a length of several centimetres, there are of course several millimetre long straight portions. at the slightly swollen tips, the development of a small medulla consisting of several medullary siphons can be observed (fig. 14f); these could also be terminal cortical siphons. finally, it must be stressed that it is unkown whether the laterally fused plates all belong to one algal thallus or are just different specimens that use other algal plates as a substrate instead of metazoan skeletons or rudistid shells. the fact, that in the fused zones, the internal structure of the main plate changes, can be taken as an indication as being parts of one and the same specimen. comparisons: the characteristic features of the new genus gosavisiphon as already discussed also account for its type-species. for instance, the special feature of gosavisiphon paucimedullaris with the isolated cortical fragments was also reported from boueina marondei flügel (= halimeda marondei acc. to dragastan et al., 1999 = halimeda cylindracea acc. to dragastan et al., 2002) from the upper triassic of thailand (flügel, 1988). in this species, post-mortem disintegration was facilitated by a »distinct break in the calcifi cation« between the medulla and the outer cortex. in boueina marondei, however, the medulla is of comparable width amounting to more than half of the cylindrical segments, thus, being totally different from gosavisiphon paucimedullaris. stratigraphy: specimens of gosavisiphon paucimedullaris (schlagintweit & ebli) were detected in the lower gosau subgroup within the middle turonian to upper santonian interval. within the branderfl eck formation it was observed within olistolites of middle/late cenomanian to early turonian age. the observed stratigraphic range of gosavisiphon is therefore middle/late cenomanian – santonian. it is most likely that this time interval does not represent its total stratigraphic range, especially at its upper boundary when neritic settings disappeared within the gosau group. palaeoenvironment: gosavisiphon paucimedullaris grew in sheltered palaeoenvironments of partly sandy unconsolidated mud associated with calcareous green algae halifigure 13: brownish calcifi cation in dasyclada lean algae (a–c) and alga incertae sedis (d) asso ciated with gosavisiphon paucimedullaris (schlagintweit & ebli) associated in the tem pestite layers of the hofergraben, gosau. a) jodotella koradae (dieni, massari & radoicic). b) trinocladus tripoli tanus raineri. c) neomeris mo kragorensis radoicic & schlagintweit. d) oro seina pletza chensis schlagintweit & ebli (o). a b c d geologia croatica 63/1geologia croatica 48 me da sp., neomeris mokragorensis radoičić & schlagintweit, dissocladella? pyriformis schlagintweit, terquemella? intermedia pia, terquemella? n. sp., oroseina pletzachensis schlagintweit & ebli, thyrsoporella eisenbachensis schlagintweit & lobitzer (only at the eisenbach locality) and benthic foraminifera vidalina hispanica schlumberger, quinqueloculinids, cuneolinids, tetrataxiella? fl oriformis schlag intweit & sanders, gastropods, ostracods and remains of land plants. within this facies, fi ne grains of pyrite may be present within chambers of benthic foraminifera or algal pores. gosavisiphon also occurs in fl oatstones with debris of rudistids and stromatoporoids (noth-klamm, gams locality). the monotypic assemblage from the tempestite beds within the santonian hofergraben marls, are high-energy accumulations where the plates of gosavisiphon may show parallel arrangement/orientation (fig. 9a). these tempestites most obviously accumulated some distance from the original low energy habitat of the alga. it is noteworthy, that epibionts or encrustations were never observed on the algal plates of gosavisiphon. the microfacies and the accompanying microfauna and fl ora account for a sheltered, terrestrially infl uenced lagoonal setting of presumably nutrient-rich waters, where rudistid biostromes occur in lateral association. the strata containing gosavisiphon paucimedullaris generally follow the basal clastics (conglomerates, breccias, sandstones) of the transgressive lower gosau subgroup. 5. conclusions halimeda paucimedullaris schlagintweit & ebli, being a non-segmented platy siphonous green alga, represents the type-species of the so far monospecifi c new genus gosavisiphon. it represents a pluricentrimetric cretaceous seaweed (macroalga) that is so far only known from the upper cretaceous of the northern calcareous alps. it fl ourished in soft-bottom, terrigeneous infl uenced lagoonal environments, attached to biogenic hard substrates. the known figure 14: hypothetical reconstruction, thin-section interpretation of gosavisiphon paucimedullaris (schlagintweit & ebli) (a, c–m), used cortex nomenclature compared to the permian anchicodium (b) (explanation in the text). a, c–d, g–j reconstructions; e) thin-section showing several series (1–3) of branching fi laments in the cortex. f) tip of a plate. k–m transverse sections of plate, m) with lateral fusion. a b c d e f g h j i k l m felix schlagintweit: gosavisiphon gen. nov. based on halimeda paucimedullaris schlagintweit & ebli, 1998: a remarkable macroalga... geologia croatica 49 stratigraphic range is middle/upper cenomanian to santonian. for reasons of pragmatism and taxonomic simplifi cation gosavisiphon is tentatively placed in the family udo teaceae and can be excluded as a candidate for the hali medaceae. with its membraneous architecture it can generally be compared with the non-systematic 'phylloid algae' with their discontinuous appearance in the late palaeozoic (late carboniferous–early, p.p. late permian) and late triassic (norian) reefal platform margin deposits. in contrast to late palaeozoic aragonitic phylloid algae that were in most cases strongly altered by diagenesis, the specimens of gosavisiphon exhibit many clearly discernible internal features. with these new fi ndings and interpretation, the stratigraphic record of phylloid algae with siphonous internal structures becomes much broader, again witnessing a huge gap in the jurassic–lower cretaceous interval. this offers further possibilites for future discussions, for instance about the phylogeny of the calcareous green algae as some late palaeozoic phylloid algae were already compared with a few extant taxa of the udoteaceae by some palaeontologists. the fi ndings of ovoid fl attened segments of halimeda sp. in the middle/late turonian of the lower gosau subgroup are the oldest records of this morphological type allowing direct comparisons with extant representatives of the genus. so far, comparable segments were not known prior to the early tertiary with halimeda eocaenica morellet & morellet. middle/upper triassic to early cretaceous representatives referred to halimeda show cylindrical segments with circular cross sections and can, in my opinion, not be directly compared with extant species of halimeda. this interpretation is completely different from previous assumptions, not accepted by all subsequent workers, that the fi rst appearance of the genus is from the late permian. based on the segment morphology as one of the main important features of fossil representatives, the fi rst halimeda s. str. seems to appear around the lower/upper cretaceous boundary, substantiated by the turonian fi ndings. acknowledgement many thanks to harald lobitzer (bad ischl), diethard sanders (innsbruck) and michael wagreich (vienna) for providing the thinsections analyzed in the present study. baba senowbari-daryan (erlangen) and ioan bucur (cluj-napoca) are thanked for kindly providing photographs of anchicodium and allowing their illustration. the picture of modern udotea has been provided by tonći grgasović (zagreb). the reviewers ivan gušić (zagreb) and baba senowbari-daryan (erlangen) are thanked for their detailed reviews and helpful remarks. references agassiz, l. (1880): report on the florida reefs.– memoirs of the museum of comparative zoologie at harvard college, 7, 1–61. baars, d.l. (1992): kansaphyllum, a new late pennsylvanian phylloid algal genus.– journal of palaeontology, 66, 697–701. bassoullet, j.p., bernier, p., deloffre, r., genot, p., jaffrezo, m., poignant, a.f. & segonzac, g. (1975): réfl exions sur la systématique des dasycladales fossiles.– géobios, 8, 259–290. bassoullet, j.p., bernier, p., deloffre, r., génot, p., poncet, j. & roux, a. (1983): les algues udoteacées du paléozoïque au cénozoïque.– bulletin centre recherches exploration-production elf-aquitaine, 7, 449–621. berger, s. & kaever, m.j. (1992): dasycladales – an illustrated monograph of a fascinating algal order.– thieme stuttgart, 247 p. böhm, e.l. (1973): studies on the mineral content of calcareous algae. – bulletin of marine science, 23, 177–190. boyd, d.w. (2007): morphology and diagenesis of dimorphosiphon talbotorium n. sp., an ordovician skeleton-building alga (chlorophyta: dimorphosiphonaceae).– journal of paleontology, 81, 1–8. braga, j.c., martin, j.m. & riding, r. (1996): internal structure of segment reefs: halimeda algal mounds in the mediterranean miocene.– geology, 24, 35–38. bucur, i.i., munnecke, a., granier, b. & yan, j. (2009): remarks on the permian dasycladalean alga sinoporella leei yabe, 1949.– géobios, 42, 221–231. chuvashov, b.i., luchinina, v.a. & shuysky, v.p. (1987): iskopaemye izvestkovye vodorosli (fossil calcareous algae).– akademiya nauk sssr, sibirskoe otdelenie, trudy instituta geologii i geofi ziki, 674, 1–200 (in russian). colombo, p.m. (1978): an ultrastructural study of thallus organization in udotea petiolata.– phycologia, 17, 227–235. colinvaux, l.h. & graham, e.a. (1964): a new species of halimeda.– nova hedwigia, 7, 5–10. conard, m. & rioult, m. (1977): halimeda elliotti nov., algue calcaire (chlorophyceae) du turonien des alpes-maritimes (s.e. france).– géologie méditerranéenne, 4, 83–98. conrad, m.a. & varol, b. (1990): cylindroporella taurica, n. sp., urges to review different patterns of calcifi cation in the mesozoic dasycladales (green algae).– archives de séances genève, 43, 193–214. crowley, d.j. (1969): algal bank limestones in wyandotte limestone (late pennsylvanian) in eastern kansas.– state geological survey of kansas bulletin, 198, 1–52. curtis, n.e., dawes, c.j. & pierce, s.k (2008): phylogenetic analysis of the large subunit rubisco gene supports the exclusion of avrainvillea and cladocephalus from the udoteaceae (bryopsidales, chlorophyta).– journal of phycology, 44, 761–767. davies, p.j., braga, j.c., lund, m. & webster, j.m. (2004): holocene deep water algal buildups on the eastern australian shelf. – palaios, 19, 598–609. de castro, p. (1997): introduzione allo studio in sezione sottile delle dasicladali fossili.– quaderni dell´ accademia pontaniana, 22, 1–137. dragastan, o. (2008): mesozoic and cenozoic calcareous algae, praecursors of family codiaceae.– acta palaeontologica romaniae, 6, 83–95. dragastan, o. & herbig, g.h. (2007): halimeda (green siphonous algae) from the paleogene south of the central high atlas (morocco) – taxonomy, phylogeny and paleoenvironment.– micropaleontology, 53, 17–72. dragastan, o., kube, b. & richter, d.k. (1999): new late triassic calcareous algae from hydra., greece.– acta paleontologica romaniae, 2, 139–156. dragastan, o., littler, d.s. & littler, m.m. (2002): recent vs. fossil halimeda species of angaur island, palau and adjacent western pacifi c areas.– acta palaeontologica romaniae, special publication, 1, 3–20. dragastan o, littler, d.s., littler, m.m. (2003): fossil siphonaceous green algal diversity of key largo and miami limestone formations – south florida (part i).– analele universitatii bucureşti geology, special publication, 1, 5–56. geologia croatica 63/1geologia croatica 50 dragastan, o., mertmann, d. & ahmed, s. (1993): jurassic calcareous algae of the indus basin (pakistan).– in: barattolo, f., de castro, p. & parente, m. (eds): studies on fossil benthic algae.– bolletino della societá paleontologica italiana, special volume, 1, 185–195. dragastan, o., richter, d.k., kube, b., popa, m., sarbu, a. & ciugulea, i. (1997): a new family of paleo-mesozoic calcareous green siphons-algae (order bryopsidales, class bryopsidophyceae, phylum siphonophyta).– revista espanola de micropaleontologia, 29, 69–135. elliott, g.f. (1965): the interrelationships of some cretaceous codiaceae (calcareous algae).– palaeontology, 8, 199–203. elliott, g.f. (1982): a new calcareous green alga from the middle jurassic of england: its relationships and evolutionary position.– palaeontology, 25, 431–437. faupl, p., pober, e. & wagreich, m. (1987): facies development of the gosau group of the eastern part of the northern calcareous alps during the cretaceous and the paleogene.– in: flügel, h.w. & faupl, p. (eds): geodynamics of the eastern alps. springer, berlin, 142–155. flügel, e. (1975): kalkalgen aus riffkomplexen der alpin-mediterranen obertrias. – verhandlungen der geologischen bundesanstalt, jg. 1974, 2–3, 297–346. flügel, e. (1988): halimeda: paleontological record and palaeoenvironmental signifi cance.– coral reefs, 6, 123–130. flügel, e. (2004): microfacies of carbonate rocks – analysis, interpretation and application.– springer, berlin, 976 p. flügel, e. & flügel-kahler, e. (1980): algen aus den kalken der trogkofel-schichten der karnischen alpen.– carinthia ii, 36 (special volume), 113–182. forsythe, g.t.w., wood, r. & dickson, j.a.d. (2002): mass spawning in ancient reef communities: evidence from late palaeozoic phylloid algae.– palaios, 17, 615–621. gaupp, r. (1982): sedimentationsgeschichte und paläotektonik der kalkalpinen mittelkreide (allgäu, tirol, vorarlberg).– zitteliana, 8, 33–72. génot, p. (1980): les dasycladacées du paléocène supérieur et de l´eocène du bassin de paris.– mémoires de la société géologique de france, 138, 1–40. génot, p. (1985a): les chlorophycées calcaires: anatomie comparée de quelques caulerpales et dasycladales actuelles et cénozoiques. – 110e congrès national des societés savantes, montpellier, 1985, sciences, 5, 209–220. génot, p. (1985b): calcifi cation in fossil neomerae (dasycladales). – in: toomey, d.f. & nitecki, m.h. (eds): palaeoalgology – contemporary research and applications. springer, berlin, 264– 272. gong, e., samankassou, e., changqing, g., yongli, z. & baoliang, s. (2007a): paleoecology of pennsylvanian phylloid algal buildups in south guizhou, china.– facies, 53, 615–623. gong, e., zhang, y., guan, c., samankassou, e. & sun, b. (2007b): paleoecology of late carboniferous phylloid algae in southern guizhou, sw china.– acta geologica sinica, 81, 566–572. gradstein, f.m., ogg, j.g. & smith, a.g. (2004): a geologic time scale 2004. cambridge university press, 1–589. grammer, g.m. & ritter, a.l. (2008): phylloid algal mounds in the paradox basin u.s.a. – an alternative in situ constructional growth model? – in: swart, p.k., mckenzie, j. & ebern, g.p. (eds.): perspectives in sedimentary geology. spec. pub., 40, 239–254. guiry, m.d & guiry, g.m. (2009): algaebase. – world-wide electronic publication, national university of ireland, galway. http:// algaebase.org harbaugh, j.w. (1960): petroline bank limestones of lansing group (pennsylvanian), southeast kansas.– state geological survey of kansas bulletin, 134, 289–331. hillis, l. (1991): recent calcifi ed halimedaceae.– in: riding, r. (ed.): calcareous algae and stromatolites. springer, berlin, 167–188. hillis, l. (1999): phylogeny of halimeda (bryopsidales): linking paleontological, morphological and molecular data.– acta palaeontologica romaniae, 2, 183–189. hillis, l., engman, j.a. & kooistra, w.h.c.f. (1998): morphological and molecular phylogenies of halimeda (chlorophyta, bryopsidales) identify three evolutionary lineages.– journal of phycology, 34, 669–681. hillis-colinvaux, l. (1977): halimeda and tydemania: distribution, diversity and productivity at enewetak. proceedings third international coral reef symposium, rosenstiel school of marine and atmospheric science, university of miami, 365–370. hillis-colinvaux, l. (1980): ecology and taxonomy of halimeda: primary producer of coral reefs.– advances in marine biology, 17, 1–327. hillis-colinvaux, l. (1984): systematics of the siphonales.– in: irvine, d.e.g. & john, d.m. (eds): systematics of the green algae. academic press, new york, 271–286. höfling, r. (1985): faziesverteilung und fossilvergesellschaftungen im karbonatischen flachwasser-milieu der alpinen oberkreide (gosau-formation).– münchner geowissenschaftliche abhandlungen, 3, 1–206. hubmann, b. (1990): udoteaceen (grünalgen) aus dem grazer paläozoikum/österreich (barrandeikalke, eifelium).– facies, 22, 147–158. hubmann, b. (1994): the oldest udoteacean green algae known from austria: paralitanaia carnica n. sp. (carnic alps, lower devonian, lochkovian).– neues jahrbuch für geologie und paläontologie monatshefte, 6, 329–338. hubmann, b. (2000): zeapora penecke 1894 redefi ned: a halimedacean alga.– mitteilungen der österreichischen geologischen gesellschaft, 91, 31–37. hubmann, b. & fenninger, a. (1997): pseudopalaeoporella und das problem der unterscheidung paläozoischer halimedaceen – gymnocodiaceen.– geologisch-paläontologische mitteilungen innsbruck, 22, 85–99. jablonski, d. (2005): mass extinctions and macroevolution.– paleobiology, 31, 192–210. james, n.p., wray, j.l. & gisnburg, r.n. (1988): calcifi cation of encrusting aragonitic algae (peyssonneliaceae): implications fort he origin of late palaeozoic reefs and cements.– journal of sedimentary geology, 58, 291–303. johnson, j.h. (1946): lime-secreting algae from the pennsylvanian and permian of kansas.– bulletin of the geological society of america, 57, 1087–1120. johnson, j.h. (1956): archaeolithophyllum, a new genus of palaeozoic coralline algae.– journal of paleontology, 30, 53–55. khvorova, i.v. (1946): a new genus of algae from the middle carboniferous deposits of the moscow basin.– comptes rendus de l´academie des sciences de l´urss, 23, 737–739. kirkland, b.l., moore, c.h. & dickson, j.a.d. (1993): well preserved aragonitic phylloid algae (eugonophyllum, udoteaceae) from the pennsylvanian holder formation, sacramento mountains, new mexico.– palaios, 8, 111–120. klinghardt, f. (1942): das krönner-riff (gosauschichten) im lattengebirge. – mitteilungen des alpenländischen geologischen vereines (mitt geol ges wien), 35, 179–213. kooistra, h.c.f., coppejans, e.g.g. & pyri, c. (2002): molecular systematics, historical ecology, and phylogeography of halimeda (bryopsidales).– molecular phylogenetics and evolution, 24, 121–138. kollmann, h.a. (1963): zur stratigraphischen gliederung der gosauschichten von gams.– mitteilungen der gesellschaft der geologieund bergbaustudenten österreich, 13, 189–212. felix schlagintweit: gosavisiphon gen. nov. based on halimeda paucimedullaris schlagintweit & ebli, 1998: a remarkable macroalga... geologia croatica 51 kollmann, h.a. (1965): stratigraphie und tektonik des gosaubekkens von gams (steiermark, österreich).– jahrbuch der geologischen bundesanstalt, 107, 71–159. kollmann, h.a. & summesberger, h. (1982): excursions to coniacian-maastrichtian in the austrian alps.– wgcm 4th meeting 1982 vienna, 1–104. konishi, k. & wray, j.l. (1961): eugonophyllum, a new pennsylvanian and permian algal genus.– journal of paleontolgy, 35, 659–666. kühnel, j. (1932): udotea adnetensis nov. spec., eine alge des rhät aus der familie der codiaceen.– neues jahrbuch für mineralogie, geologie und paläontologie, beilagen-band 69b, 347–352. leiss, o. (1988): die kontrolle des sedimentationsgeschehens und der biofazies durch evolutive orogenetische prozesse in den nördlichen kalkalpen am beispiel von gosauvorkommen.– documenta naturae, 43, 1–95. liebezeit, g. & dawson, r. (1982): changes in the polysaccharide matrix of calcareous green algae during growth.– publications cnexo, 14, 147–154. littler, d.s. & littler, m.m. (1990): systematics of udotea species (bryopsidales, chlorophyta) in the tropical western atlantic. – phycologia, 29, 206–252. littler, d.s. & littler, m.m. (1992): systematics of avrainvillea (bryopsidales, chlorophyta) in the tropical western atlantic.– phycologia, 31, 375–418. mamet, b. & vila, e. (2004): calcareous marine algae from the carboniferous (moscovian-gzhelian) of the cantabrian zone (nw spain).– revista espanola de paleontologia, 19, 151–190. maslov, v.p. (1956): fossil calcareous algae of the ussr.– trudy geological institut sssr, 160, 1–301. masse, j.-p. & bucur, i.i. (2002) : generic reappraisal of angioporella? bakalovae conrad & peybernes (1978): early cretaceous dasycladalean from the carpatho-balkanic realm. – in: bucur, i.i. & filipescu, s. (eds.): research advances in calcareous algae and microbial carbonates. cluj university press, 157–165. medlin, l.k. (2007): molecular clocks and inferring evolutionary milestones and biogeography in microalgae.– in: okada, h., mawatari, s.f., suzuki, n. & graham, p. (eds): origin and evolution of natural diversity. proceedings international symposium the origin and evolution of natural diversity, 1–5 octobre 2007, sapporo, 31–42. morellet, l. & morellet, j. (1922): contribution á l ´ètude paléontologique du genre halimeda lamouroux.– bulletin de la societé géologique de france, 22, 291–296. morellet, l. & morellet, j. (1940): etude sur les algues calcaires de l´eocene du contentin.– bulletin de la societé géologique de france, 10, 201–206. moussavian, e., höfling, r. & herm, d. (1993): facies development of the eastern alpine cretaceous with respect to algal associations.– alpine algae, field trip guide book a3, 1–27. mu, x. (1991): fossil udoteaceae and gymnocodiaceae.– in: riding, r. (ed.): calcareous algae and stromatolites, springer, berlin, 146–166. nizamuddin, m. (1963): studies on the green alga, udotea indica a. & e.s. gepp, 1911.– pacifi c science, 7, 243–245. pal, a.k. (1971): on the algal genera arabicodium, boueina and halimeda (codiacean algae) in the bagh group of madhya pradesh. – quarterly journal of the geological, mining and metallurgical society of india, 43, 131–140. pia, j. (1932): remarques sur les algues calcaires. – in: pia, j., pfender, j. & termier, h.: etudes géologiques sur les calcaires de bekrit et de timhadit (moyen-atlas).– notes et mémoires du service mines cartes géologique du maroc, 20, 13–18. pia, j. (1936): calcareous green algae from the upper cretaceous of tripoli (north africa).– journal of palaeontology, 10, 3–13. pia, j. (1942): uebersicht über die fossilen kalkalgen und die geologischen ergebnisse ihrer untersuchung.– mitteilungen des alpenländischen geologischen vereines (mitteilungen der geologischen gesellschaft in wien), 33, 11–34. poncet, j. (1989): présence du genre halimeda lamouroux, 1812 (algue verte calcaire) dans le carbonifère supérieur du sud tunisien.– revue de micropaléontologie, 30, 117–121. pray, l.c. & wray, j.l. (1963): porous algal facies (pennsylvanian), honaker trail, san juan canyon, utah. in: bass ro (eds) shelf carbonates of the paradox basin.– four corners geological society symposium 4th field conference, 204–234. radoičić, r. (1984): new species and new subgenus of neomeris (dasycladaceae, green algae) from the upper cretaceous of metohija.– bulletin académie serbe des sciences and arts, classe des sciences mathématiques et naturelles, 49, 65–81. ratschbacher, l., frisch, w., neubauer, f., schmid, s.m. & neugebauer, j. (1989): extension in compressional orogenic belts: the eastern alps.– geology, 17, 404–407. reid, p.r. (1986): discovery of triassic phylloid algae: possible links with the palaeozoic.– canadian journal of earth sciences, 23, 2068–2071. ries, j.b. (2006): aragonitic algae in calcite seas: of seawatermg/ca ratio on algal sediment production.– journal of sedimentary research, 76, 515–523. roux, a. (1985): introduction à l´étude des algues fossiles paléozoiques (de la bactéric à la tectonique des plagues).– bulletin du centres recherches exploration-production elf aquitaine, 9, 465–699. ruttner, a. & woletz, g. (1955): die gosau von weisswasser bei unterlaussa.– mitteilungen der österreichischen geologischen gesellschaft, 48, 221–256. sanders, d. (1998): tectonically controlled late cretaceous terrestrial to neritic deposition, gosau group, northern calcareous alps (tyrol, austria).– facies, 39, 139–178. sanders, d. & baron-szabo, r. (2007): palaeoecology of solitary corals in soft-substrate habitats: the example of cunnolites (upper santonian, eastern alps).– lethaia, 41, 1–14. sanders, d. & pons, j.m. (1999): rudist formations in mixed siliciclastic-carbonate depositional environments, upper cretaceous, austria: stratigraphy, sedimentology, and models of development. – palaeogeography, palaeoclimatology, palaeoecology, 148, 249–284. sawin, r.s. & west, r.r. (2005): paleoecology of the permian (wolfcampian) phylloid alga calcipatera from an in situ occurrence in kansas, u.s.a.– current research in earth sciences bulletin, 251, 1–14. schlagintweit, f. (1991): dissocladella? pyriformis n. sp., new chlorophycean alga from the upper cretaceous of the northern calcareous alps (gosau formation/branderfl eck formation).– revue de micropaléontologie, 34, 191–200. schlagintweit, f. (1992): further record of calcareous algae (dasycladaceae, udoteaceae, solenoporaceae) from the upper cretaceous of the northern calcareous alps (gosau formation, branderfl eck formation).– revue de paléobiologie, 11, 1–12. schlagintweit, f. (1993): benthonische foraminiferen aus flachwasserkarbonaten der oberkreide der nördlichen kalkalpen (gosauschichtgruppe, österreich).– mitteilungen der österreichischen geologischen gesellschaft, 84, 327–353. schlagintweit, f. (2004): calcareous green algae from the santonian hochmoos formation of gosau (northern calcareous alps, austria, lower gosau subgroup).– zitteliana, a44, 97–103. schlagintweit, f. & ebli, o. (1998): halimeda paucimedullaris n. sp. and oroseina pletzachensis n. sp., two new calcareous algae from the upper cretaceous of the northern calcareous alps.– revue de paléobiologie, 17, 361–371. geologia croatica 63/1geologia croatica 52 schlagintweit, f. & lobitzer, h. (2003a): thrysoporella eisenbachensis n. sp., a new dasycladale (calcareous alga) from the upper cretaceous gosau group of eisenbach (austria; salzkammergut).– in: weidinger, j.t., lobitzer, h. & spitzbart, i. (eds): beiträge zur geologie des salzkammergutes. gmundner geo-studien, 2, 133–140. schlagintweit, f. & lobitzer, h. (2003b) halimeda paucimedullaris schlagintweit & ebli, 1998 (calcareous green alga) from the lower santonian gosau group of hofergraben (salzkammergut, upper austria).– in: weidinger, j.t., lobitzer, h. & spitzbart, i. (eds): beiträge zur geologie des salzkammergutes. gmundner geo-studien, 2, 159–164. schlagintweit, f. & sanders, d. (2008): tetrataxiella? fl oriforma n. sp. and other benthic foraminifera from the gosau group of the northern calcareous alps.– austrian journal of earth sciences, 101, 17–26. schlagintweit, f. & weidich, k.f. (1991): fazies, alter und herkunft kretazischer olistolithe (alb-turon) der branderfl eckschichten (cenoman-coniac) der lechtal-decke in en nördlichen kalkalpen.– zeitschrift der deutschen geologischen gesellschaft, 142, 229–249. senowbari-daryan, b. & hamadani, a. (1999): girvanella coated udoteacean oncoids from the upper triassic (norian-rhaetian) nayband formation, south of abadeh (central iran).– revue de paléobiologie, 18, 597–606. senowbari-daryan, b. & rashidi, k. (in press): the codiacean genera anchicodium johnson, 1946 and iranicodium gen. nov. from the permian jamal formation of shotori mountains, northeast iran.– rivista italiana di paleontologia e stratigrafi a. senowbari-daryan, b. & rigby, j.k. (2007): hikorocodium, not an alga but an inozoid sponge.– canadian journal of earth sciences, 44, 149–154. senowbari-daryan, b., schlagintweit, f. & sanders, d. (2004): acanthochaetetes? krumbachensis n. sp., (hadromerida, demospongia) from the upper cretaceous gosau group of brandenberg (northern calcareous alps, austria).– revue de paléobiologie, 23, 267–274. senowbari-daryan, b. & zamparelli, v. (2005): triassic halimedaceans: new genera and species from the alps, sicily and southern apennines.– revista espanola de micropaleontologia, 37, 141–169. senowbari-daryan, b., zühlke, r., bechstädt, t. & flügel, e. (1993): anisian (middle triassic) buildups of the northern dolomites (italy): the recovery of reef communities after the permian/triassic crisis.– facies, 28, 181–256. siegl-farkas, a. & wagreich, m. (1997): correlation of palyno (spores, pollen, dinofl agellates) and calcareous nannofossil zones in the late cretaceous of the northern calcareous alps (austria) and the transdanubian central range (hungary).– geological survey of hungary – advances in austrian-hungarian joint geological research, 127–135. silva, p.c. (1980): names of classes and families of living algae: with special reference to their use in index nominum genericorum.– regnum vegetabile, 103, 1–156. silva, p.c., basson, p.w. & moe, r.l. (1996): catalogue of the benthic marine algae of the indian ocean.– university of california publications in botany, 79, 1–1259. steinmann, g. (1899) ueber boueina, eine fossile alge aus der familie der codiaceen.– berichte der naturforschenden gesellschaft freiberg im breisgau, 11, 62–72. steuber, t. (2001): strontium isotope stratigraphy of turonian-campanian gosau-type rudist formations in the northern calcareous alps (austria and germany).– cretaceous research, 22, 429–441. summesberger, h. & kennedy, w.j. (1996): turonian ammonites from the gosau group (upper cretaceous; northern calcareous alps; austria) with a revision of barroisiceras haberfellneri (hauer 1866).– beiträge zur paläontologie, 21, 1–75. summesberger, h., wagreich, m. & bryda, g. (2009): upper maastrichtian cephalopods and the correlation to calcareous nannofossils and planktic foraminifera zones in the gams basin (gosau group; styria, austria).– annalen des naturhistorischen museums wien, 111a, 159–182. toomey, d.f. (1976): paleosynecology of a permian plant dominated marine comunity.– neues jahrbuch für geologie und paläontologie abhandlungen, 152, 1–18. torres, a.m. (1995): ivanovia tebagaensis was a cyathiform permian codiacean membranous alga with dimporphic cortices.– journal of paleontology, 69, 381–387. torres, a.m. (1997): reconstruction of a cyathiform eugonophyllum, upper pennsylvanian, palo pinto county, texas.– journal of paleontology, 71, 493–499. torres, a.m. (2003): sexual reproductive structures in the green alga ivanovia triassica.– lethaia, 36, 33–40. torres, a.m. & baars, d.l. (1992): anchicodium johnson: branched or phylloid.– journal of palaeontology, 66, 675–677. torres, a.m., west, r.r. & sawin, r.s. (1992): calcipatera cottonwoodensis, a new membranous late palaeozoic alga.– journal of paleontology, 66, 678–681. vachard, d. & cózar, p. (2006): the family calcifoliaceae emend., mississippian-early pennsylvanian algae.– rivista italiana di paleontologia e stratigrafi a, 122, 23–34. vachard, d., hauser, m., martini, r., zaninetti, l., matter, a. & peters, t. (2001): new algae and problematrica of algal affi nity from the permian of the aseelah unit of the batain plain (east oman).– géobios, 34, 375–404. verbruggen, h. (2005): resegmenting halimeda – molecular and morphometric studies of species boundaries with agreen algal genus.– phd thesis ghent university 213 p. (www.phycology.ugent. be/reprints/resegmenting_halimeda.pdf) verbruggen, h., ashworth, m., loduca, s.t., vlaeminck, c., cocquyt, e., sauvage, t., zechman, f.w., littler, d.s., littler, m.m., leliaert, f. & de clerck, o. (2009): a multi-locus time-calibrated phylogeny of the siphonous green algae.– molecular phylogenetics and evolution, 50, 642–653. verbruggen, h., de clerck, o., schils, t., kooistra, w.h.c.f. & coppejans, e. (2005): evolution and phylogeography of halimeda section halimeda (bryopsidales, chlorophyta).– molecular phylogenetics and evolution, 37, 789–803. verbruggen, h. & kooistra, w.h.c.f. (2004): morphological characterization of lineages within the calcifi ed tropical seaweed genus halimeda (bryopsidales, chlorophyta).– european journal of phycology, 39, 213–228. verbruggen, h., littler, d.s. & littler, m.m. (2007): halimeda pygmaea and halimeda pumila (bryopsidales, chlorophyta): two new dwarf species from fore reef slopes in fiji and the bahamas.– phycologia, 46, 513–520. verbruggen, h. & theriot, e.c. (2008): building trees of algae: some advances in phylogenetic and evolutionary analysis.– european journal of phycology, 43, 229–252. vickers, a. & shaw, m. (1908): phycologia barbadensis.– paul klinsieck, paris, 44 p. wagreich, m. (1988): sedimentologie und beckenentwicklung des tieferen abschnittes (santon-untercampan) der gosauschichten von gosau und rußbach (oberösterreich-salzburg).– jahrbuch der geologischen bundesanstalt, 131, 663–686. felix schlagintweit: gosavisiphon gen. nov. based on halimeda paucimedullaris schlagintweit & ebli, 1998: a remarkable macroalga... geologia croatica 53 wagreich, m. (1990): bericht 1989 über geologische aufnahmen in der kalkalpinen oberkreide auf blatt 69 großraming.– jahrbuch der geologischen bundesanstalt, 133, 423–433. wagreich, m. & decker, k. (2001): sedimentary tectonics and subsidence modelling of the type upper cretaceous gosau basin (northern calcareous alps, austria).– international journal of earth sciences, 90, 714–726. wagreich, m. & faupl, p. (1994): palaeogeography and geodynamic evolution of the gosau group of the northern calcareous alps (late cretaceous, eastern alps, austria).– palaeogeography, palaeoclimatology, palaeoecology, 110, 235–254. wagreich, m., kollmann, h.a., egger, h., grachev, a.f. & summesberger, h. (2009): excursion guide to reccce workshop.– berichte der geologischen bundesanstalt, 78, 49–74. wahlman, g.p. (2002): upper carboniferous-lower permian (bashkirian-kungurian) mounds and reefs.– in: kiessling, w., flüge, l.e. & golonka, j. (eds): phanerozoic reef patterns. sepm special publication, 72, 271–338. weidich, k.f. (1984): feinstratigraphie, taxonomie planktonischer foraminiferen und palökologie der foraminiferengesamtfauna der kalkalpinen tieferen oberkreide (untercenoman-untercampan) der bayerischen alpen.– abhandlungen der bayerischen akademie der wissenschaften, mathematisch-naturwissenschaftliche klasse, 162, 1–151. weigel, o. (1937): stratigraphie und tektonik des beckens von gosau.– jahrbuch der geologischen bundesanstalt, 87, 11–40. weiss, w. (1977): die korrelation küstennaher und küstenferner faziesbereiche in den unteren gosauschichten (oberkreide, österreich).– neues jahrbuch für geologie und palöntologie monatshefte, 1977, 289–302. wille-janoschek, u. (1966): stratigraphie und tektonik der schichten der oberkreide und des alttertiärs im raume von gosau und abtenau (salzburg).– jahrbuch der geologischen bundesanstalt, 109, 91–172. yu-ying, w. (1976): calcareous algae from the late cretaceous and palaeogene sediments in the mount jolmo lungma region.– academia sinica, 2, 425–457. manuscript received august 06, 2009 revised manuscript accepted december 04, 2009 available online february 28, 2010 i geol. croat . 49/2 183 187 1 tab. i i zagreb 1996 i professional paper the petroleum fiscal regime and oil company status boro vlasi<': and hrvoje lipov ac key words: transition, exploration contract, state leg­ islature, fiscal terms, licence. abstract in {he foreseeable future the republic of croatia wi ll be inc luded in lhe market economy as a consequence of recent widespread socia l changes . the oi l il1cillslry will also be a ffected by these changes, inevitably becoming a part of the wider markel, and it will have 10 adjust its business practice accordingly . to facil itate the inevitable lransilion of ina into a modern and profitable company, capable of su rvival in the market, it is necessary 10 create favourable business envi ronment s for possi bl e eco nomic grow th and development. as a nrs( step towards this goal it is neces­ sary for the state o f croat ia to adjust its legal sys tem to be compatible wi th those prevaili ng in the market economy. there arc several differe nt !ega i approaches in world prac tice specific for a particular country, and one has to take 1hem into consid­ eratio n while creating lega l relat ions in thc oil industry in croatia. here it comparison is made between the present legal stat us in croatia and some of the o thers abroad. an op timal solution is proposed from the viewpoi nt of the company dealing with the o il industry. 1. introduction oil production in croatia is declining remarkably as a consequence of a lower replacement rate of reserves. the natural decli ne of remaining reserves as a conse­ qucnce or oi l deplc li on, is partly slowed down by the introduct ion or secondary recovery methods. however, the bes t replacement of reserves are new d iscoveries, because on ly on newly discovered pools can various technological applications give optimal results using human and techno logica l resources. lengthy discussi ons havc already taken place in the compan y as to the reasons ror the delay of reserve replaccment, whether it was the inefficiency or explo ­ ra tion, the delayed introduction of new exploration tech nologies (modern seismic equ ipment, informatics, 3d scismic and so on) or maybe insistence of intensive exploration in mature basins where major discoveries or new rese rves cannot be expected. 'white & geh ­ man (1979) investigated the remaining potential of mat ure basins, and showed that after the first di scover­ ics in a gi vcn basin , larger fi elds arc then discovered lna -naftaplin, subiceva 29, hr 10000 zagreb, croatia. proceedings quickly, but any remaining fields are more numerou s but with less reserves. analysis of the company's suc­ cessful discoveries produces the same sce nario . the assesment of the cause of decay of successfu lness in exploration will enable the right strategic deci s ions to be made. the earlier prevailing opinion of ina was that increased accomplishment of the company would be achieved by improved technology and better expert ise. although these factors are relevant in the oil industry, the natural conditions of the area where the technology and knowledge are applied are even more important. in the panonian basin, there is a real possibility of finding new reserves , examination of remai ning potential reserves indicates that it is not possib le to find suffi cient quantiti es of new reserves to replace thc reserves decline. there has been no change in strategy requi red to look for new exploration opportunities. such a change l11 ust now occur under less than per­ fect condit ions dur ing a recess ion in the oil indust ry and after a war. the present status of the oil market strongly influences the potential entrance of foreign investors into oil exploration in croatia. since rest ructuring of the oil industry in croatia has not yet taken place, and the government control s both natu ra l resou rces and ina, (the only oil producer in the country, state owned), there is an opportunity to reshape the oil business so that it is compatible to other oil producing co untries . more inves tment is now required for prospects abroad and foreign in ves tors must be attracted to the croatian oil industry. this requires croat ia to develop a clear legislative system and become competent in cu r­ rent world practice, thus provid ing the stab le opera­ tional condi tions attractive to such investors. the aim or the paper is to compare the croatian lega l system as app lied to the oil industry with the legislalure in coun­ tri es where we have somc cxperiencc. these are not only countries where we have participated in ex plo­ ration, either as an operator or as a partner. confiden­ tiality res tricts this analysis to generalities, precluding disclosure or detailed inrormation. 2. the role of the state the fi scal regime is one of the mos t important fac ­ tors in creating a business environment toget her with political and natural factors. a fiscal regime is a collee184 tion of conditions which a host country demands an oil company to fulfill in cxchangc for thc right to undcr­ take cxploration and production of oil and gas in a lim­ itcd arca of its tcrritory. the precise nature of these condit ions depends on illany factors, of which thc following arc somc of thc most important: prospcctivity of the exploration area; political risk in the country; competitivness of the oil industry comparcd to other industries; macro economic policy of the country; general status of developmcnt of the country. depending on thc asscssment of the above factors, a host country will create its fiscal policy, and prescribe under which conditions it will temporarily give explo­ ration rights on part of its terittory. it is important that the above fac tors are objectively assessed and balanced with fiscal measures, i.e. the fiscal regime must be such that exploration projects arc suffic iently attractive for pot ential investors (or comparable with others available on the market) . it also must protect the interest of the host country, in other words it must enable the country to participate advantageously in ruture production. the host country can claim its share in different ways, dircctly or through an agency, or through a national oil company by: royalty; production sharing; profit sharing; income taxes; profit taxes; additionaltaxcs (cxport quotas etc.); bonus paymcnts. the country legally defincs, most often by a petro­ leum law, thc basic terms which are applied to thc whole count ry. some of the above parameters are nego­ tiable, and they are usually stip ulated in thc bidding for an exploration area. the negotiations arc held between an oil compa ny and the govern ment representativc (government agency, national oil company and some­ times ministry for natural resou rces). it is important that once agreed contracts are unchanged during the whole life of the project, as this provides security. in many cases the law is changed sllccessively depending on changes of the country's policy or prospectivity of exploration area, but once signed agreements, remain empowered until the end of the project. 3. types of the agreements in the exploration and production of orland gas the types of agreements can be divided into two mal11 groups: geologia cwatie:t 49/2 royalty(tax agreements or concession agreements production sharing agreements or contracts royalty/tax agreements or concession agree­ ments are such agreements where the government or country transfers the title of mineral resources to the company, and the company is subject to tax and royalty payments. this kind of agreements is becoming obso­ lete, and more rarely used. production sharing agreements the great major­ ity of current agreements in the countries that arc major oil producers, are production sharing agreements. a basic difference between this type of agreement and a concess io n agreemelll is ownership o f mineral resources. in this type or agreement the government reta ins the ownership of minerals , while the oil compa­ ny invests money in exploration, development and sur­ face facilities taking the risk. the oil company on the other hand is allowed a certain percentage or oil or gas for cost recovery (cost oil) and fo r profit (profit oil). all equipment and objects included in the agreement become the ownership of the host country immediately after sign ing the agreement or after starting production. heavy service equ ipment for drilling and wcll opera­ tions are exc luded . the company has a right to cost recovery for that purpose. there arc many additiona l detail s in differcnt agreements which, for example, specify the right to interests on invested capital, amorti­ zation, rate of cost recovery and others. besides production sharing agreements there are variants when the host country through its agency o r national company forms a joint company for exp lo­ ration and production financing, taking a certain per­ centage of working interest, i.e. join t venlltre agree­ ments. such a company is subject to all the lega l regu­ lations in the host country. along with these basic items which define the rela­ tionship between the owner of the mineral resources and a foreign company, (sometimes rcferred to as the contractor), the agreement contains additional content s including a work program, ent itlement to the data coor­ dinates of the area covered by the agreement, relin­ quishment after a certain phase, duration of the agree­ ment , rcporting of financial issues etc. at the same time the obligations of the country or a national oil company are defined, including access to data, assistance during agreement implementation , nomination of authorised representatives, project supervision, cost control etc. the agreement usually defines a myriad of other de tails which enable operations to be carried out with­ out any misunderstanding, but they don't determine the attractiveness of a country for investment in oil and gas exploration and production. some countries, especially those in transition from a socialist to capitalist system, treat their own oil compa­ nies differently to fore ign ones. some countries, e.g. italy, in past years, had exploration areas exclusively reserved for agip, albania for albpetrol, etc. the national oil companies of some other countries also act ylasic & lipovac ' illc 1\:ll"olculil fiscal regime and oil company status structure of the concession type of agreement gross income country royalty (usually 12.5 %) extra profit tax income tax company capital expenditures. operati ng costs net cash flow for the company structure of the production sharing agreement company take cost oil for: • explorat ion • development · investment profit oil or gas for company income tax capital expenditures operating expenditures gross income by project royalty cost oil profit oil = net cash flow for the company country take profit oil for country as operators, as well as taking eare or the organisation and superv ision of exploration and production of for­ eign companies, e.g. sonalraeh in algeria, noc in libya, and to some extent sonangol in angola. 4. croatian legislature the rights and obligations of a company and an individual person engaged with exploration are deter­ mined by the mining law, published in "narodne novinc" , zagreb, on may 26, 1995 . accord ing to this law, all organ ic and inorganic mineral resources arc some countries with concession type agreements abu dhabi algeria (unlil1991) argentina (1990) france ireland morocco norway pakistan thailand tunisia (special iype) uk 185 considered mineral resources owned by the republic of croatia. the law also defines all technical and legal details related to obtaining licenses for oil and gas exploration and production, but less so to business activities themselvcs. one of the provisions of the min­ ing law is the obligation to usc a part or any income (minimum 3%) earned from the sale of minerals, for mineral reserves exploration. a mineral royalty (com­ pensation for the exploration of mineral resources) is 2.5%, and represents the revenue of the republic of croatia which is assigned to municipalities or c ities. the croatian government establishes the amount of compensation/royalty percentage. also "if a mining company or an individual person owns the discovered reserves of mineral resources classified as a+b cate­ gories for exploration, they are not obligated lo allocate cunds for exploration in the following 25 years." this docs not reveal what kind of production is involved. a "licence for exploration or exploitation of miner­ al resources can be granted to a company located in the republic of croatia and registered for the performance of such activities (in further text mining company) and to citizens which arc cngaged in this economic activity with their own work registered in the republic of croa­ tia (in futher lext individual entrepreneur)". a licence for oil and gas exploration and exploitation is grantcd by the government of the republic of croatia. licences cannot be transferred to another physical or legal per­ so n without permission of the authority who granted them and cannot be the subject of bankruptcy or liqui­ dation. the law imposes limi ts on certain exploration rights 111 a glvcn area. besides these provisions which have been sligh tly elaborated, the law defines the right to mineral resources exploi tat ion. it is granted to a mining compa­ ny or an individual enterpreneur if they have earlier performed exploration activities in this arca. some countries with production sharing agreements albania algeria (aller 1991) angola egypt (since 1986) gabon india indonesia libya malesia malta nigeria syria turkmenistan vietnam uzbekistan jemen furthermore, the law provides for the manner, con­ ditions and rights concerning mineral resources explo­ itation, managing and recording of reserves, necessary techni ca l documentation, land-reg istry of exploration areas and exploitation fi el ds, the required professional and other capacities of workers, safety measures, super­ vision and finally, penalty measures. several articles of the law anticipate the preparation of several by-laws such as: "bylaw on the contents of an annual program of exploration, the procedure of the application for cxploration liccnce, and the details of the licensing procedure", " by-law on the contents of the application for ex ploitation licence" etc. the by-law on the cont ent s of an annual program of explorat ion , the procedure of the applicat ion for exploration licence, and content s of the reports on performed exploration activities, dctermines the terms for submittal of annual reports and plans , contents of the application for licence, etc. furthermore, thi s by-law establishes some very important parameters related to exploration rights, such as li cence duration/validity (3 years), work pro­ gram, exploration area, and deviation from the under­ taken obligations of work program during application for ex ploration rights. there is no time duration of pro­ duction rights. art. no. is of the above by-law is very interesting and reads as follows: the size of exploration area is determined according to/based on: planned exploration activi ties on the basis of which reserves of mineral res ources can be estab li shed belonging to at least category c; (the amount 01) available financial funds; obligation to carry out planned exploration activities at the lates t within a period set in the art. 13, line i or ihis by-law. it can be observed from the above that the legislator who prescribed the reg ulations and obli gations related to oil and gas exploration and production, did not take into account world practice existing in the oil industry. most countries have a special law covering this branch of industry owing to the fact that the oil industry is sig­ nificantly different from all olhers, a lthough it can be agreed that it is most similar to other mining activities. if we wish to summarize the fiscal regime in the republi c of croatia accord ing to the mining law , it could be expressed as: co mpany obligation: to offer a minimal work program; to provid e necessary financial funds (there is no indication of how it is going to be checked); to provide adequate means of production; company alone proposes the area of their interest. oncc the company has been granted an explorat ion licence, their obligation is to: geologia cro:l1ica 49/2 perform operations envisaged in the annual work program; report on plan realisation; report on invested fund s; make a final report; continually report on the di scovery of new hydrocarbon reserves (which is prescribed by a totally dif­ rerenl by-law). once there is a discovery of hydrocarbon reserves, the company is obligated to: provide a licence for the fi eld exploitation; the exploitation licence is gran ted conditionally by technological and personnel suitability; there is no time limit for the licence; company status towards the state is not defined . although the mining law docs not explieitely state it, the total rcvcnue shou ld be divided in the follow ing way: total rev enue ( from oil and gas production and sale) 2.5 % of total reven ui3 for ti-ie state, local self~management 3% of total revenue for the purpose of exploration or undiscov[red reserves capital expenditure operating expenditure tax income 25% ~ net casii flow table l shows the com pari son between the state's take and the oil company' s take in different types or agreements. it is obvious that an oil company's take in croatia, for one field yielding 10 mil. tons, and under the afore­ mentioned conditions, is sign ificantly higher than in any other country, thc contracts of which we were able to use [or comparison. consequently, a conclusion can be drawn that our present legal system insufficienliy protects the state interests in the case of forcign compa­ nies entering direclly into agreement with thc sta le. 5. conclusion according to the above analysis we may conclude that the existentlegisiature in the republic of croatia is not transparent enough, and that it cannot serve as the basis for sign ing one of the known types of contract with the clearly defined rights and obl igations of the state on one side, and th e oil company on the other. practically, the state cannot protect its interest without the strong presence of a national oil company, which need not ajways be acceptable to a foreign company as a potential inves tor. yi;liii~ & lipov;lc: '!lle petroleum riseal regime and oil company status cro.ati.an t.ax regime compulsory explorat ion expendi tu res 3% optional exploration expenditures 32% capilal expenditures 20% operating expenditures 10% royalty (2.5% of revenue) 3% tax (35% of profit) 11% net profit 21 % structure or typica l concession type tax regime compulsory explorat ion expenditures 3% optional exploration expenditures 32% capi181 expenciitu res 20% operating expenditures 12% royahy (816% or revenue) 8% tax (35-50% of profit) 9% net profit 16% structure of' typical production sharing coni ract cost oil (30-80%) state profit oil (40-90%) company profit oil (1 0-60%) tabte t comparison of different lypes of tax reg imes . 50% 40% 10% the law does not de fine how to obtain an explo­ ration area. there is no bidding procedure whereby the bes t offers cou ld be se lccted . the law determines the percentage of total revenue for investment in explo­ ration, but it is not ag reed on how much should be in vested in an exp lorati on area. the tim e limit for investment in exploration , which is not determined by the law, but by a by-law, is only 3 years for the cycle of geo logy-geophys ics, exp loration and drilling. the law does not define the period of production rights. in other words, accordi ng to thc current law, the state can­ not ge t an income from oil adequatc to the practice in ot her oil and gas producing countries, but at the same time it does not clearly guarantee to an oil company any safety of long term investment. considering the interes t of a croatian oi i company undertakjng exploration abroad, it is obvious that a dol­ lar invested in croatia brings considerably morc return than a dollar invested abroad, with the same geological and polilical ri sk, the same reserves and the same work co nditions. under the same contractua l conditions the percentage of net present value belonging to a company deducted from net present value per project, ranges from 1:3 to 1:2. conseguent ly, the probab ility of oil discovery or the size of an expl oration area abroad, should be in a reverse relat io nship in favour of the international project if we want to invest in this project. in order to formulate a decision on selecting a pro­ jec t for investm ent , one sho uld carefully com pare all avai lable projects using available economic and techni ­ cal parameters. one should choose the proj ec ts that indicate the fastest return on investment and the highest profit. 6, reference white, d.a. & gehman , m. (1979): method s o f est imating oi l and gas resourees.aapg bulletin, 63/ 12,2183-2 192. 'rs geologia croatic:l 49/2 pikelj.indd 95 �ab stra ct granulometric, mineralogical and morphological investigation of the sea-bottom sediments in the grgur channel has revealed fi ve sediment types, the most frequent of which are muds containing some amount of coarse fractions (sand and gravel). the coarsest fractions are predominantly composed of recent shell fragments. unexpected well rounded carbonate gravel was found se of prvić island in 83 m of water. this gravel was presumably transported, shaped and deposited during a sea-level lowstand, by stream and/or in a beach environment. fine-grained fractions have a siliciclastic composition and suggest a predominant terrigenous origin. one part of the fi ne-grained fraction originates from the recent subaerial weathering of fl ysch outcrops, and the other from previously active (during a lower sealevel), subaerial erosion of presently submerged fl ysch outcrops. as a result of the rapid late pleistocene–holocene transgression, the investigated sediments are now below the present wave-base. due to a presumed very low or even negligible rate of recent sedimentation in the study area, older sediments in the grgur channel remain uncovered and bioturbated by burrowing organisms. therefore, analyzed surface sediments from the grgur channel are considered as a mixture of recent and subrecent deposits. from this investigation, a new seabed sediments map of the grgur channel was produced, as an improvement on the existing sedimentological map of the kvarner area. keywords: late pleistocene, holocene, gravel, depositional environments, kvarner origin and distribution of surface sediments in the grgur channel, adriatic sea, croatia � kristina pikelj1, višnja žigić2 and mladen juračić1 1 department of geology, faculty of science, university of zagreb, horvatovac 102a, 10000 zagreb, croatia; (kpikelj@geol.pmf.hr; mjuracic@geol.pmf.hr) 2 prilaz ivana visina 7, siget, 10000 zagreb, croatia doi: 10.4154/gc.2009.08 geologia croatica 62/2 95–105 8 figs. 2 tabs. zagreb 2009 geologia croaticageologia croatica 1. introduction seabed sediments of the adriatic sea have been intensively investigated since the 1960s, but the previous studies were sporadic. sediments of the northern, middle and western parts of the adriatic sea were investigated by italian and other researchers (brambati & venzo, 1967; brambati et al., 1983; brambati et al., 1988a, b; pigorini, 1968; van straaten, 1970), while the eastern part remained poorly explored. however, lorenz (1863) published an initial map of the seabed and surface sediments of the kvarner region. further investigation in this region was only resumed more than a century later (alfirević, 1964, 1980; škrivanić & magdalenić, 1979; juračić & pravdić, 1981; hijrm, 1985; juračić et al., 1997, 1999). the seabed sediment map produced by lorenz (1863) showed that the grgur channel bottom is mostly covered with clay, except for narrow zones along the prvić, grgur and goli island coastline, where a barren rocky bottom is present and/or covered with angular clasts and pebbles. alfirević (1980) indicated that coarse sandy sediments prevail along the goli island coasts; loamy-clayey sediments were registered in the area between grgur and the velebit channel, while the grgur channel remained unexplored. according to the general map of the adriatic sea seabed sediments (hijrm, 1985), the grgur channel is covered with clayey sands. in the more detailed map of the seabed sediments of the kvarner region (juračić et al., 1999) the grgur channel bottom sediments are classifi ed as sandy muds. geologia croatica 96 geologia croatica 62/2 the sea-fl oor sediment sampling and this study were carried out within a project entitled “preservation of biodiversity in adriatic sea”, in order to eventually establish a marine park in the prvić, grgur and goli island area (zavodnik et al., 2005). the main aim of this paper is to determine the pattern and origin of the surface sediment distribution, in order that investigation of sediment properties might also enhance the understanding of general sedimentation mechanisms in the channel area of the eastern adriatic coast under the recent and subrecent climate conditions. another purpose of this study is to supply detailed data for a new sediment map of the kvarner area (and the eastern adriatic coast in whole), by publishing a refi ned surface sediment distribution map of the grgur channel. 2. study area the prvić, goli and grgur islands belong to the krk – rab – pag island chain that separates kvarnerić bay and the velebit – vinodol channel within the kvarner area (kvarner sensu lato). about 4 km long and 3 km wide, the grgur channel is located between the islands of prvić, goli and grgur (fig. 1). water depths in the channel increase abruptly up to 70 m off the coast, and gradually deepen toward the central part (95 m). in the ne and se part of the channel, two seafl oor depressions occur (fig. 1). the maximum depth of the channel at 107 m occurs in one of these, south of prvić island (hhi, 1997). regarding solid rock geology, the kvarner area belongs to the nw part of the adriatic carbonate platform (adcp). it is characterized by predominantly shallow-marine carbonate deposits, ranging in age from the lower jurassic to the top of the cretaceous. the end of adcp shallow marine deposition was marked by a regional emergence between the cretaceous and palaeogene, but deposition controlled by synsedimentary tectonics continued throughout the palaeogene. compressional tectonics with maximum stress oriented sw–ne resulted in the fi nal uplift of the dinarides in the oligocene/miocene (vlahović et al., 2005). according to blašković (1999), two main geodynamic phases shaped the kvarner area: eocene tectonic movements formed faulted and folded structures, whereas upper pliocene tectonics caused their reactivation. due to the intensive tectonics, uplifted carbonates were crushed and karstifi ed under subaerial conditions during the pleistocene. karstifi cation progressed to a signifi cant depth during the last glacial maximum (lgm) (surić et al., 2005) when the sea-level was at least 100 m lower than present (correggiari et al., 1996). due to the sea-level rise in the post-lgm period, the karst relief was fl ooded and the modern rocky eastern adriatic coast was formed (benac & juračić, 1998; surić et al., 2005). in the investigated area, the data available on the solid rock geology are restricted to outcrops on the islands. as shown in fig. 2, several stratigraphic members can be distinguished on prvić, goli and grgur: upper cretaceous (cenomanian–turonian) limestones with breccias dominate on all islands, palaeogene deposits are composed of carbonate (eocene foraminiferal limestones) and clastic sediments (eocene fl ysh marls with inclusions of sandstone). eocene foraminiferal limestones, wich transgressively overlie the upper cretaceous deposits, are best exposed in the ne and sw parts of grgur island, but due to the reverse faulting on prvić island, these sediments can only be observed in a narrow strip in its sw part. eocene fl ysch (marls and sandstones) were discovered on each of the three islands: on grgur and prvić within disturbed synclines and on goli between two longitudinal faults. the youngest stratigraphic member developed on each of these islands are eocene breccias and fi gu re 1: a) location maps. b) bathymetric map of the grgur channel area. legend: 1) water depths 0–50 m; 2) water depths 50–100 m; water depths over 100 m; 4) sediment sampling station; 5) sampling depths; (after hhi, 1997). a b geologia croatica 97 pikelj et al.: origin and distribution of surface sediments in the grgur channel, adriatic sea, croatia conglomerates, deposited as a result of erosion of the older (cretaceous limestones and eocene fl ysch) sediments (korolija & borović, 1966; mamužić & milan, 1973). from a general structural point of view, the grgur and goli islands form a faulted fl ank of a syncline, while prvić is interpreted as a part of an anticline, overturned in the northern-western part of the island (fig. 2). according to korolija & borović (1966) monoclinal layers and reverse faults confi rm such a structural setting. as shown in fig. 2 and according to the structural features, the grgur channel is considered to be a submerged part of a syncline with its core composed of eocene fl ysch. 3. materials and methods 3.1. sampling and sample preparation sea-bottom sediment samples investigated in this paper were collected in 1995 during the cruise of the r/v “vila velebita”. the samples were taken by a van veen grab along four transects (at 13 locations) in water depths between 65 and 88 m (fig. 1). samples were air-dried and approximately 100 g of each sample were used for analysis. 3.2. grain-size analysis grain size composition of the sampled sediments has been determined by wet sieving through an astm standard sieving set (diameter (d) > 32 μm) on fritsch analysette and by a particle coulter coulter counter ta ii (d < 32 μm). sediments were then classifi ed according to the internationally accepted classifi cation of sediments (folk, 1954). 3.3. mineralogical analysis the qualitative mineral composition of bulk sediment samples was determined by the philips x`pert pro x-ray diffractometer. relative mineral abundances were estimated based on the intensity of major peaks. in addition, randomly chosen gravelly grains from sample 11 were powdered and analyzed on the same diffractometer. the amount of carbonates was determined by gas volumetry (jobstraibizer, 1970). 3.4. grain-shape analysis each fraction of the sediment samples was examined with a binocular microscope. grain morphology analysis was carried out only on the gravelly fraction of sample 11 (see discussion in 4.3). pebbles were counted and weighed, and short (s), intermediate (i) and long (l) axes of clasts were determined, using a slide caliper. according to i/l and s/i ratio, the shape of each clast was categorized into sphere, rod, disc and blade, using the zingg classifi cation (zingg, 1935). roundness and sphericity of the grains were determined using a visual comparative graphic chart (graham, 1988; tucker, 2003). aditionally, the degree of grain fl atness (fl atness index) was calculated from the l, i and s ratio, using the formula: f= l+i/2s (müller, 1967). fi gu re 2: geological map and cross-section of the grgur channel area. legend: 1) quaternary in general; 2) palaeogene and neogene carbonate breccias; 3) eocene fl ysch marls and sandstones; 4) eocene foraminiferal limestones; 5) upper cretaceous limestones, limestones with dolomite intercalations and limestones with breccias; 6) upper cretaceous dolomites and dolomite breccias; 7) lower cretaceous limestones and breccias; 8) upper jurassic layered limestones with dolomites; 9) upper jurassic breccias and limestones with dolomites; 10) middle jurassic massive limestones; a) transgressive contact; b) normal contact; c) fault without its character; d) presumed fault; e) reverse fault; (simplifi ed after korolija & borović, 1966; mamužić et al., 1969; mamužić & milan, 1973). geologia croatica 98 geologia croatica 62/2 3.5. micropalaeontological analysis pebbles for micropalaeontological analysis of the gravelly fraction in sample 11 were randomly chosen and used for preparation of thin sections in order to defi ne the rock type according to dunham (1962). 4. results 4.1. grain-size analysis results of grain size analysis of sediments from the grgur channel showed a mean grain size between 12 and 70 μm with predominance of the mud fraction (silt + clay) 44–92 % (table 1). sediments were classifi ed according to folk (1954) into fi ve sediment types: mud (m–8, 12), sandy mud (sm–2, 5, 7), slightly gravelly sandy mud ((g)sm–4, 6, 9, 10, 13), slightly gravely muddy sand ((g)ms–1, 3) and gravelly mud (gm–11) as shown on fig. 3a. the map (originally at the scale of 1:100000, fig. 3b) shows an almost symmetrical distribution of sediment types in the channel regarding its elongate shape. 4.2. mineralogical analysis the analyzed sediments have a similar mineralogical composition, which is a mixture of carbonaceous and aluminosilicate components including quartz. the total content of table 1: summary results of the grain size and mineralogical analyses* sample sampling depth (m) gravel (%) sand (%) silt (%) clay (%) mz (μm) so carbonates (%) non-carbonate minerals sediment type (folk, 1954) 1 84 0.8 51.3 44.8 3.1 50.7 2.13 55.6 q, ms, chl slightly gravely muddy sand 2 88 0.0 37.6 58.8 3.6 31.9 1.53 nd** nd** sandy mud 3 86 0.9 55.4 42.7 1.0 71.7 1.98 55.6 q, ms slightly gravely muddy sand 4 73 1.0 45.1 44.0 9.9 44.1 2.53 70.5 q, chl, ms slightly gravelly sandy mud 5 86 0.0 11.4 70.8 17.8 12.1 1.81 54.5 q, chl, ms sandy mud 6 65 1.1 27.5 62.0 9.4 32.5 3.40 52.3 q, ms, kln, ill, pl slightly gravelly sandy mud 7 75 0.0 38.8 49.5 11.7 27.5 2.37 59.0 q, chl, ms sandy mud 8 82 0.0 8.7 74.4 16.9 12.1 1.71 54.5 q, chl, ms, pl mud 9 79 2.7 11.9 74.2 11.2 15.6 1.71 50.0 q, ms, chl, ill slightly gravelly sandy mud 10 78 3.2 31.2 53.9 11.7 20.7 2.33 50.0 q, chl, ms, ill slightly gravelly sandy mud 11 83 14.3 22.2 46.6 16.9 44.5 3.99 52.3 q, chl, ms gravelly mud 12 88 0.0 8.2 80.1 11.7 12.6 1.48 43.2 q, chl, ms, ill mud 13 86 0.4 25.8 57.5 16.3 18.4 2.31 56.8 q, ms, ill slightly gravelly sandy mud * mineral abbreviations: chl – chlorite, ill – illite, kln – kaolinite, ms – muscovite, pl – plagioclase, q – quartz. ** nd: not determined fi gu re 3: a) folk (1954) diagram of the percentage of gravel, sand and mud with sediment types present on the seabed of the grgur channel (abbreviations explained in the text); b) surface sediment map of grgur channel, bar scale: 1) isobath 50 m; 2) isobath 100 m; 3) sediment sampling station; 4) sampling depths (after hhi, 1997). b a geologia croatica 99 pikelj et al.: origin and distribution of surface sediments in the grgur channel, adriatic sea, croatia carbonate minerals varied between 43.2 % (sample 12) and 70.5 % (sample 4), averaging 54.5 % (table 1). all samples contained calcite, (as the most abundant mineral), mg-calcite and aragonite, mostly deriving from shell fragments. the second major mineral was quartz, the amount of which increased in the central part of the channel (samples 2, 5, 8, and 12). secondary minerals occurring within the sediments were dolomite, chlorite, muscovite and/or illite, while traces of plagioclase and kaolinite were also found. results of the x-ray analysis of the gravel fraction in the sample 11 revealed that all analyzed grains only contained calcite. 4.3. grain-shape analysis sand and gravel in all of the samples consisted of various biogenous remains, except for the two coarsest (2–4 mm, >4 mm) fractions in sample 11, which contained only rock fragments. because of this unusual fi nding, grain-shape analysis was only carried out for those fractions. the gravel fraction of sample 11 amounted to 14.3 % by weight and 89 grains were counted. figure 4 shows a zingg diagram of grain shapes (zingg, 1935). almost half of the grains fell in the disc fi eld (47.2 %). spheroids were represented by 20.2 %, rods by 19.1 % and blades by 8.9 %. a small percentage of the grains (4.4 %) had boundary values: 3.3 % between discs and spheres and 1.1 % between discs and blades. summary results of grain roundness and grain fl atness are presented in table 2. most of the grains were rounded (32.6 % well-rounded, 24.7 % rounded and 25.8 % sub-rounded). the fl atness index (müller, 1967) ranged between 1.09 and 5. in table 2 measured fl atness indices were divided into three groups: < 1.6, 1.6–2 and > 2 %). 4.4. micropalaeontological analysis microfossil assemblages from the examined limestone pebbles indicated an age range from the lower cretaceous to middle eocene. fossil remains of pseudonummoloculina aurigerica calvez (fig. 5a) discoverd in a peloidal-miliolidal grainstone, indicate the lower cretaceous (late aptian–early albian). fragments of algae thaumatoporella parvovesiculifera rainier in several different grains indicate a wider stratigraphic range (upper triassic to palaeogene). however, together with the benthic foraminifera pseudolituonella reicheli marie and fragments of broeckina (p.) balcanica cherchi et al. in peloidal wackestone (fig. 5b), this indicates a middle cenomanian age. grains of peletal foraminiferal wackestone containing alveolina sp., chrysalidina sp., orbitolites sp. and triloculina sp. (fig. 5c) confi rmed their eocene age. in a few rounded and well-rounded pebbles from the gravelly fraction of sample 11, polychaete and anthozoan remnants were found (fig. 6a and 6b). being poorly preserved, determination of the polychaete species was not possible. remains of the anthozoa, (also deeply weathered), belong to the juvenile form of the solitary coral balanophyllia europaea risso (fig. 6b and 6c) (p. kružić, 2006, personal communication). 5. discussion 5.1. seabed sediment distribution the distribution of sediment types in the channel is symmetrical along the channel (figs. 3 and 7). sediments from the central part of the channel contain the largest amount of mud (samples 5, 8 and 12; > 88 %). peaks of the muddy modes lay in the fi ne silt fraction (~8 μm, except for sample 3 occuring at 16 μm) (fig. 7). the proportion of the coarse fractions increases westward and shoreward in the channel. the sandy fraction content of the samples ranges between 8 and 55 % with the modal peak occurring mostly at 63 μm. fi gu re 4: zingg diagram of grain shape for the gravelly fraction of sample 11, according to intermediate (i)/ long (l) and short (s)/ intermediate (i) axes ratios; (after zingg, 1935). table 2: summary results of the grain shape analysis roundness: % very angular 4.5 angular 3.4 subangular 9.0 subrounded 25.8 rounded 24.7 well-rounded 32.6 sphericity: % high 23.6 low 76.4 average values for the flatness: % < 1.6 27.0 1.6–2 29.2 > 2 43.8 geologia croatica 100 geologia croatica 62/2 samples 2, 5, 7 contain more sand than previous ones and were classifi ed as sandy muds, while samples 4, 6, 9, 10, 13 were classifi ed as slightly gravelly-sandy mud, also containing a slightly increased gravel fraction. the highest precentage of sand (> 50%) was found in samples 1 and 3, classifi ed as slightly gravelly muddy sand (fig. 3). the gravel content of the investigated samples is low (0–3.2 %), except for sample 11 (14.3 %). visual inspection of this fraction revealed differences between the biogenic origin of this fraction in most of the samples and the terrigenous origin of the gravel fraction in sample 11, as discussed below. poor and very poor sorting (table 1), together with noticeable bimodal and polimodal frequency curves, respectively, (fig. 7) indicate that all of the analyzed sediment samfi gu re 5: a) aptian–albian limestone with pseudonummoloculina aurigerica calvez; b) cenomanian assemblage of pseudolituonella reicheli marie (fragment in oval) and broeckina (p.) balcanica cherchi et al. (fragments in circles); c) eocene foraminiferal limestone with (from left to right) triloculina sp., chrysalidina sp., orbitolites sp. and alveolina sp. (fragments). fi gu re 6: a) gravel grain with remains of a polychaete; b) gravel grain with remains of an anthozoan, balanophyllia europaea (risso); c) balanophyllia europaea (risso), sem, bse. a b c a b c geologia croatica 101 pikelj et al.: origin and distribution of surface sediments in the grgur channel, adriatic sea, croatia ples are mixtures of mud with coarser fractions (sand and gravel) in different proportions. these results mainly confi rmed the previous characterization of the grgur channel bottom sediments as sandy muds (juračić et al., 1999). greater distinction between the sediment types has additionally refi ned the existing seabed sediment map (fig. 3). 5.2. origin of sediments the pronounced bimodal or polymodal distribution and poor sorting (table 1, fig. 7), indicate the various origins of particles found in sediments. aditionally, nearly equal proportions of carbonate and siliciclastic fractions suggests different sources of particles. the main thesis arising from these results is that the seabed sediment contains particles of biogenic and terrigenous origin, suggesting the possibility of different times of deposition. the analyzed sediments, with sampling depths between 65 and 88 m, are below the present wave base. an absolute maximum wave height in the adriatic recorded during the longlasting southeastern wind jugo, (or scirocco in italian), in the open northern adriatic was hmax = 10.8 m and the average wave length was lav = 112.3 m (hhi, 1999). thus, the deepest wave base in the open adriatic is of the order of 50 m. since the study area is protected by the southern and external islands (fig. 1a), the wave base here is signifi cantly shallower. therefore, at the investigated sea depths, only fi ne-grained terrigenous particles should be expected. however, the results of both granulometric and mineralogical analysis have shown that, as already emphasized, all of analyzed samples have a bimodal/polymodal distribution (fig. 7) and are mixtures of carbonaceous and siliciclastic material to different extents (table 1). 5.2.1. fine-grained fraction the fi ne-grained fraction of the analyzed sediments (< 63 μm) contains aluminosilicate minerals. quartz, as the second major mineral present, together with muscovite and/or illite, plagioclase and kaolinite, indicates a terrigenous source. such a mineral composition of the fi ne grained fraction is similar to the composition of fl ysch deposits of central istria and the kvarner littoral area (with various percentages of carbonates, quartz as the main component and plagioclase, illite, chlorite and montmorilonite as secondary components) (magdalenić, 1972). moreover, some beach sands on rab island have been recognised as material supplied by weathering of siliciclastic eocene sandstones in the nearby hinterland (lužar-oberiter et al., 2008), while similar mineral assemblages, belonging to the kvarner province, can be found in the bottom sediments of the velebit channel, rijeka bay, northern parts of kvarner and the kvarnerić channel (škrivanić & magdalenić, 1979). eocene fl ysch outcrops (marls and sandstones), exposed to present subaerial weathering that could contribute to sediment supply in the channel occur only on prvić island. this fl ysch might be the source of part of the aluminosilicate minerals present (fig. 2). these outcrops are both scarce and presumably too small to be the main source of the siliciclastic component of the sea-bed sediments. a possible major source of this component could have been the seabed of the channel itself. mamužić et al. (1969) interpreted the channel as the submerged part of a syncline, composed of eocene fl ysch sediment. during the lower sea-level, specifi cally during the last glacial period, most of the presently submerged parts of the channel were dry land (fig. 8) (benac & juračić, 1998). such exposed fl ysch bedrock could have been weathfi gu re 7: grain-size frequency distribution of sediment samples in the grgur channel. geologia croatica 102 geologia croatica 62/2 ered under subaerial conditions. with the onset of the rapid holocene transgression, this weathered non-lithifi ed fl ysch debris probably remained on the bottom of the infi lled channel. 5.2.2. sand and gravel fractions the coarser-grained fraction (> 63 μm) of the sediment samples contained large amount of skeletons, shells and fragments of different marine organisms. thereby, the major part of the carbonate fraction (including calcite, mg-calcite and aragonite) is of biogenic origin. most of skeletal remains are sand sized (63 μm–2 mm), while a minor part is determined as gravel (> 2 mm). since these particles are of biogenic orig in, their size is a result of the original skeletal size and some degree of fragmentation. considering the predominant carbonate lithology of the mainland and the islands in the investigated area, (which is more prone to chemical weathering/karstifi cation), the actual terrigenous input into the investigated area was pressumed to be low (benac & juračić, 1998). however, dolomite determined as a secondary mineral in the sandy fractions, confi rmes the terrigenous origin of part of the carbonate fraction. grgur channel coasts (fig. 2) are exposed to marine erosion (benac, 1992), especially due to waves generated by the jugo. such abrasion could produce small amount of sand-sized particles. unlike other samples, sample 11, collected from a depth of 83 m, shows an intriguingly high proportion of gravel (14.3 %). this gravelly fraction is composed only of rock granules and very fi ne pebbles, whereas bioclastic particles are absent. referring to the afore-mentioned hydrodynamic setting, the gravelly part of this sediment is obviously not in accordance with the present depositional environment. in order to determine the depositional conditions of this gravel, pebbles were morphologically analyzed. the shape of sedimentary particles is a complex property, depending on many factors (initial mineralogy, weathering degree, transport abrasion degree, transport distance, fl uid energy etc). weathering of rocks of homogenous texture produces spherical, discoidal and isometric grains (tišljar, 2004). within the analyzed pebbles, 47.2 % were discs and 20.2 % were spheres (fig. 4), suggesting high transport energy and/or noticeable transport length. x-ray analysis showed that all of the pebbles are composed of calcite and micropalaeontological analysis showed that the gravel source rocks are limestones having age ranges from the lower cretaceous (aptian–albian) to middle eocene. these source rocks are well stratifi ed (mamužić & milan, 1973). if weathered, stratifi ed limestone produces tabular grains, which results in the dominance of discs. thereby, high fl atness indices (> 40 % of the analyzed grains) could be attributed to the structure of a source rock. therefore, we presume that the high percentage of discs in the gravel fraction is controlled by the structure of the source rocks. besides the grain shape, grain roundness also confi rms a considerable transport distance and/or high transport energy: over 80 % of pebbles are sub rounded, rounded and well rounded (table 2). some of the grains, from upper cretaceous and middle eocene limestones could be transported from adjacent sources. since lower cretaceous sediments do not crop out on the surrounding islands (fig 2.), part of the gravel was probably transported from more distant sources. one possible transport direction could be from the velebit channel toward the grgur channel (fig. 8), since, according to mamužić et al. (1969), lower cretaceous deposits oucrop in part of the velebit channel seabed (fig. 2). erosion of those deposits caused by a palaeostream could produce gravelly material during a low sea-level stand, supplying the studied location with gravelly material. during the lower sea level, coastlines were shifted away from the recent ones and brackish and/or freshwater lakes could have been formed in deeper and isolated parts of the kvarner area (fig. 8). if gravel was brought and deposited by the palaeofl ow near the former coastline, it could be further shaped as beach sediment. therefore, gravelly sediment fi gu re 8: morphological evolution of the kvarner area during the last glacial period. legend: 1) position of the marine basin; 2) position of periodic lakes; 3) position of palaeofl ows; 4) continuous connection with the marine basin in the middle adriatic; 5) periodically connected with the marine basin; 6) intensive recent sedimentation; (after benac & juračić, 1998). geologia croatica 103 pikelj et al.: origin and distribution of surface sediments in the grgur channel, adriatic sea, croatia could be expected to extend along the former palaeofl ow and/or coastline. similar discoveries of gravel (cobbles) at 155 m depth in the black sea were also interpreted as an ancient lake shoreline (ballard et al., 2000). the discovery of biological owergrowths on the pebbles indicates sea-level change. balanophyllia europea (risso) (b. italica michelin), found attached to gravel, is a solitary, ahermatypic zooaxantellate scleractinian coral, about 25 mm high. it lives mostly on a rocky substratum and rarely on a sandy substratum and mollusc shells, and it is well known in the mediterranean sea and in some parts of the atlantic ocean (zibrowius, 1980; zavodnik & šimunović, 1997). it has inhabited the wider mediterranean area since the miocene (chaix & cahuzac, 2005). its depth distribution seems to be restricted due to its symbiosis with zooxantellae; it is found at a maximum depth of 50 m (zibrowius, 1980). in the adriatic sea it inhabits depths between 3 and 50 m (zavodnik & šimunović, 1997). the high degree of roundness (rounded and well-rounded grains, fig. 6) of the gravel on which the coral was found indicates that transport and/or reshaping processes must have occurred before the coral grew. therefore, the coral was probably attached while the depth of the seabed was suitable for its colonization (between 3 and 50 m). due to sea-level rise, grains with coral remains fi nally ended up below the depth suitable for coral colonisation. preservation of the attached coral′s theca proves that the pebbles were not further reworked. 5.3. general setting of the depositional environment in the grgur channel the presence of well rounded carbonate gravel, the general composition and bimodality/polimodality of the frequency curves of surface sediments in the grgur channel is considered as a good example of the documented change of depositional environment and sediment sources. the late pleistocene–holocene transgression is accepted as a reason for the change in depositional conditions. the grgur channel, as with other channels in the wider area along the croatian portion of the eastern adriatic coast, was presumably formed along the bottom of a syncline, as described in section 2 (fig 2). the investigated area belongs to the northern dalmatic province (ndp) (giorgetti & mosetti, 1969) – an insular area with water depths in channels up to 125 m, infl uenced by sea-level changes during the pleistocene. during the lower sea-level periods, parts of channels in the kvarner area were probably emergent. at the same time the outer longitudinal island chain kept the inner ndp basins out of po river dominated continental terrigenous sedimentation, typical for the northern adriatic shelf during pleistocene sea-level lowstands (benac & juračić, 1998). according to these conditions, the grgur channel as well as deeper parts of the kvarner (kvarnerić bay, vinodol channel, velebit channel) probably remained protected from infi lling with terrigenous sediments from the west, whilst some other parts of the grgur channel could have been dry land (fig. 8). exposure of its fl ysch dominated fl anks to subaerial conditions presumably produced substantial amount of debris. onset of a global sea level rise caused by rapid ice decay at the end of the mis 2 (lambeck et al., 2002), caused the depositional areas and coastlines to rapidly shift towards the recent ones. the formerly deposited sediment remained on the seabed surface and recent sedimentation has only partially covered it. the sediment is further mixed by bioturbation. defi cient recent sedimentation within the ndp is also noted in palaeontological investigations, after the discovery of fossil elephant skeletal remains on the sea-bottom between rab and laganj islands (approximately 5 km south of rab island, black dot in fig. 1a) (malez & lenardić-fabić, 1988). remains of mammuthus meridionalis adriaticus n. ssp. were found at a depth of 80 m below present sea-level, in sediment that authors have called “ancient sands”. the age of this fossil elephant was placed in the mindel glacial (mis 12–14?, lowe & walker, 1997), indicating several emersions of this area, caused by sea-level fl uctuations during the pleistocene. hence, negligible recent sedimentation in the channel is evident and resulted in thin recent sediment cover. biological effects throughout interaction with the substrate (bioturbation processes) probably helped in generating various mixtures of recent and subrecent sediment. bimodal or polymodal grain size distributions are a result and further proof of this mixing (fig. 7). for a detailed identifi cation of the thickness of individual sediment layers (if existing) at particular locations, a different sampling procedure (gravity corer, box corer) is required, since the grab sampling could further mix the sediment. investigations conducted on the surface sediment cover have revealed complex depositional mechanisms in the grgur channel, markedly conditioned by the last sea-level change. furthermore, it suggests similar depositional patterns in the channel area of the eastern adriatic coast, where similar geological settings also occur. however, every channel tends to have specifi c oceanographic characteristics, due to the complicated orography and geometry (orlić, 2001), which certainly alters the fi nal distribution of sediment types. nevertheless, these results are in accordance with the distribution of sediment types in other parts of the kvarner region. diversity of sediment types in the grgur channel certainly contributes to the high biodiversity of the bottom communities indentifi ed by zavodnik et al. (2005), which is an important factor for protecting the grgur channel area as a marine park. moreover, the channel seabed requires further investigation. in order to gain more precise information on the sediment cover and changes in sedimentation during the subrecent geological past, marine seismic techniques and sub-bottom profi ling could be used. 6. conclusions analyzed sediments of the grgur channel were sampled in the quiet depositional environment, below the present wave base. distribution of sediment types is symmetrical along geologia croatica 104 geologia croatica 62/2 the channel. common characteristics of all analysed sediment samples are bimodality/polymodality of the grain size frequency curves and a combined carbonate-siliciclastic mineral composition, suggesting different sources, transport mechanisms and times of deposition. the late pleistocene– holocene transgression is considered as a main reason for changes in the depositional conditions. the fi nest fraction is most abundant in sediment from the central part of the channel and is mostly in accordance with recent depositional conditions. the other parts of the channel seabed are covered with a mixture of fi ne and coarse grained particles that are only partially of recent origin. the most conspicuous characteristic of sediments is the unusual fi nding of well rounded carbonate gravel at a depth of 83 m, characterized as fl uvial and possibly beach sediment. this mixture of recent and subrecent sediment particles is probably due to bioturbation. thus, the analyzed sediments could be defi ned as a mixture of recent and subrecent, carbonaceous and siliceous, as well as mixture of biogenic and terrigenous particles. results of analyses of seabed sediments from the grgur channel are in line with the previous sediment investigation. they also indicate the complex origin of the seabed sediment cover in the channel area of the eastern adriatic coast. acknowledgement this work was funded by the croatian ministry of science, education and sports of project no. 119-1191152-1169, “recent sediments and fossil environment of the adriatic littoral”. the authors are grateful to blanka cvetko-tešović for assistance in micropalaeontological analy sis, to petar kružić for coral determination, and to robert košćal for drawings. we thank paolo colantoni and josip tišljar for their critical reviews which improved the early version of the manuscript. references alfirević, s. (1964): sedimentološki pokrov kanalskog područja jadrana i faktori koji uplivaju na njegovo formiranje [sediment cover of adriatic channel area and factors that infl uence its formation – in croatian].– acta adriat., 11/1, 9–17. alfirević, s. (1980): sedimentološko kartiranje bentoskih biocenoza u kanalima sjeveroistočnog jadrana [sedimentological mapping of benthos biocenoses in the channels of the ne adriatic sea – in croatian].– geol. vjesnik, 32, 15–32. ballard, r.d., coleman, d.f. & rosenberg, g.d. (2000): further evidence of abrupt holocene drowning of the black sea shelf.– mar. geol., 170, 253–261. doi: 10.1016/s0025-3227(00) 00108-0 benac, č. (1992): recentni geomorfološki procesi i oblici u području riječkog zaljeva [the recent geomorphological processes in the area of the rijeka bay – in croatian].– geogr. glas., 54, 1–18. benac, č. & juračić, m. (1998): geomorphological indicators of the sea level changes during upper pleistocene (würm) and holocene in the kvarner region (ne adriatic sea).– acta geogr. croat., 33, 27–45. blašković, i. (1999): tectonics of part of the vinodol valley within the model of the continental crust subduction.– geol. croat., 52/2, 153–189. brambati, a. & venzo, g.a. (1967): recent sedimentation in the northern adriatic sea between venice and trieste.– studi trentini. sci. nat., 44, 202–274. brambati, a., ciabatti, m., fanzutti, g.p., marabini, f. & marocco, r. (1983): a new sedimentological textural map of the northern and central adriatic sea.– boll. ocean. teor. appl., 1/4, 267–271. brambati, a., ciabatti, m., fanzutti, g.p., marabini, f. & marocco, r. (1988a): carta sedimentologica dell’ adriatico centrale, 1:250000.– consiglio nazionale delle ricerche. brambati, a., ciabatti, m., fanzutti, g.p., marabini, f. & marocco, r. (1988b): carta sedimentologica dell’ adriatico centrale, 1:250000.– consiglio nazionale delle ricerche. chaix, c. & cahuzac, b. (2005): les faunes de scléractiniaires dans les faluns du miocčne moyen d’atlantique-est (bassins de la loire et d’aquitaine): paléobiogéographie et évolution climatique [the faunas of scleractinian corals in the faluns of the eastern atlantic middle miocene (loire and aquitaine basins): paleobiogeography and climatic evolution – in italian].– ann. paléont., 91, 33–72. correggiari, a., roveri, m. & trincardi, f. (1996): late pleistocene and holocene evolution of the north adriatic sea.– il quaternario – ital. j. quat. sci., 9/2, 697–704. dunham, r.j. (1962): classifi cation of carbonate rocks according to depositional textures.– in: ham, w.e. (ed): classifi cation of carbonate rocks. amer. assoc. petrol. geol. mem., 1, 108–121. folk, r.l. (1954): the distinction between grain size and mineral composition in sedimentary rock nomenclature.– j. geol., 62, 344–356. giorgetti, f. & mosetti, f. (1969): general morphology of the adriatic sea.– boll. geofi s. teor. appl., 11, 49–56. graham, j. (1988): collection and analysis of fi eld data. in: tucker, m.e. (ed.): techniques in sedimentology. blackwell scientifi c publications, suffolk, 5–63. hhi (1997): coastal chart krk – rab mk7, scale 1:100000.– hrvatski hidrografski institut, split. hhi (1999): peljar i. jadransko more – istočna obala [nautical pilot i. adriatic sea – eastern coast – in croatian].– hrvatski hidrografski institut, split, 331 p.+d 32. hijrm (1985): jadransko more – generalna karta sedimenata dna [adriatic sea – general map of the seabed sediments – in croatian], 1: 1.000000.– hidrografski institut jugoslavenske ratne mornarice, split. juračić, m. & pravdić, v. (1981): geochemical and physicochemical studies on sediments of rijeka bay: the properties of sediments as depositories of pollutants.– thalassia jugosl., 17/3–4, 339–349. juračić, m., crmarić, r. & benac, č. (1997): holocenski sedimenti i sedimentacija u riječkom zaljevu [holocene sediments and sedimentation in the rijeka bay – in croatian].– in: arko-pijevac, m., kovačić, m., crnković, d. (eds.): prirodoslovna istraživanja riječkog područja. prirodoslovna biblioteka 1, prirodoslovni muzej rijeka, 339–344. juračić, m., benac, č. & crmarić, r. (1999): seabed and surface sediment map of the kvarner region, adriatic sea, croatia (lithological map, 1: 500000).– geol. croat., 52/2, 131–140. jobstraibizer, p.g. (1970): determinazione rapida di calcite e dolomite per via gas-volumetrica nei sedimenti.– boll. soc. geol. it., 89, 401–413. korolija, b. & borović, i. (1966): geology of the isles grgur, prvić and goli otok.– bull. scient. acad. rsf yougoslavie, 1–2, 2–3, zagreb. lambeck, k., esat, t. & potter, e.k. (2002): links between climate and sea level for the past three milion years.– nature, 419, 199–206. lorenz, j.r. (1863): physicalische verhältnisse und vertheilung der organismen im quarnerischen golfe.– kais. kön. hofund staatsdruckerei, wien, 379 p. geologia croatica 105 pikelj et al.: origin and distribution of surface sediments in the grgur channel, adriatic sea, croatia lowe, j.j. & walker, m.j.c. (1997): reconstructing qaternary environments (2nd edition).– prentice hall, 446 p. lužar-oberiter, b., mikulčić pavlaković, s., crnjaković, m. & babić, lj. (2008): variable sources of beach sands of north adriatic islands: examples from rab and susak.– geol. croat., 61/2–3, 379–384. magdalenić, z. (1972): sedimentologija fl iških naslaga srednje istre [sedimentology of central istria fl ysch deposits – in croatian].– acta geol., 7/2, 71–96. malez, m. & lenardić-fabić, j. (1988): new subspecies of the southern elephant (mammuthus meridionalis adriaticus n.ssp.) from the bottom of the adriatic sea (croatia, yugoslavia).– paleont. jugosl., 37, 1–36. mamužić, p., milan, a., korolija, b., borović, i. & majcen, ž. (1969): osnovna geološka karta sfrj 1:100.000, list rab, l 33–144 [basic geological map of sfry 1:100000, rab sheet – in croatian].– institut za geološka istraživanja zagreb, savezni geološki zavod, beo grad. mamužić, p. & milan, a. (1973): osnovna geološka karta sfrj 1:100000. tumač za list rab l33–44 [basic geological map of 1:100000, geology of the rab sheet – in croatian].– institut za geo loška istraživanja zagreb, savezni geološki zavod, beo grad, 39 p. müller, g. (1967): methods in sedimentary petrology. sedimentary petrology, part i.– schweizerbart, stuttgart, 283 p. orlić, m. (2001): croatian coastal waters.– in: cushman-roisin, m. b. et al. (eds): physical oceanography of the adriatic sea, kluwer, dordrecht, 189–214. pigorini, b. (1968): sources and dispersion of recent sediments of the adriatic sea.– mar. geol., 6/3, 187–229. surić, m., juračić, m., horvatinčić, n. & krajcar bronić, i. (2005): late pleistocene–holocene sea-level rise and the pattern of coastal karst inundation: records from submerged speleothemes along the eastern adriatic coast (croatia).– mar. geol., 214, 163–175. doi: 10.1016/j.margeo.2004.10.030 škrivanić, a. & magdalenić, z. (1979): cruises of the research vessel “vila velebita” in the kvarner region of the adriatic sea. ix. quaternary sea bottom sediments.– thalassia jugosl., 15, 149–166. tišljar, j. (2004): sedimentologija klastičnih i silicijskih taložina. [sedimentology of clastic and siliceous deposits – in croatian].– institut za geološka istraživanja, zagreb, 426 p. tucker, m.e. (2003): sedimentary rocks in the fi eld.– john wiley & sons ltd., chichester, 234 p. van straaten, l.m.j.u. (1970): holocene and late pleistocene sedimentation in the adriatic sea.– geol. rund., 60, 106–131. doi: 10.1016/j.margeo.2004.10.030 vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeography, main events and depositional dynamics.– palaeogeogr. palaeoclimatol. palaeoecol., 220, 333–360. doi: 10.1016/j.palaeo.2005.01.011 zavodnik, d. & šimunović, a. (1997): beskralješnjaci morskog dna jadrana [invertebrates of the adriatic sea-bed – in croatian].– ip svjetlost d.d., sarajevo, 217 p. zavodnik, d., pallaoro, a., jaklin, a., kovačić, m. & arko-pijevac, m. (2005): a benthos survey of the senj archipelago (north adriatic sea, croatia).– acta adriat., 46/2, 3–68. zibrowius, h. (1980): les scléractiniaires de la méditerraée et de l΄atlantique nord-oriental.– mém. inst. océanogr., monaco, 11, 1–284. zingg, t. (1935): beitrage zur schotteranalyse.– min. petrog. mitt. schweiz., 15, 39–140. manuscript received may 15, 2008 revised manuscript accepted april 23, 2009 available online june 19, 2009 bakrac.indd 259 � ab stra ct quantitative analysis of palynomorphs, foraminifera and ostracods enabled the recognition of biotic events and the reconstruction of environmental change in the badenian sediments from the vrhovčak section of mt. samoborsko gorje (nw croatia). during the middle miocene the investigated area of mt. samoborska gora was located at the south-western margin of the north croatian basin, which represents the south-western edge of the pannonian basin system and the central paratethys basin. this marginal position within the basin controlled the specifi c evolution of the depositional area during the badenian. the occurrence of coal bearing horizons and freshwater fl ora and fauna in the middle part of the vrhovčak section provide new data for the reconstruction of badenian palaeoenvironments. a fall in sea level and the probable isolation of this area in the badenian seems to be responsible for the appearance of a new fauna and fl ora. the marine sediments from the base of the vrhovčak section may be correlated to cycle tb 2.4 of the main badenian transgression, which affected the entire central paratethys area. this was followed by a regression and lowstand (ser2), which, correlated to the middle part of the section, with freshwater sediments and coal bearing horizons. the upper part of the vrhovčak section with marine sediments represents the late badenian cycle tb 2.5. keywords: miocene, badenian, north croatia basin, coal bearing horizons, palaeoecology, biostratigraphy evidence for badenian local sea level changes in the proximal area of the north croatian basin � koraljka bakrač*1, valentina hajek-tadesse1, mirjana miknić1, anita grizelj1, ivan hećimović1 and marijan kovačić2 1department of geology, croatian geological survey, sachsova 2, 10 000 zagreb, croatia *corresponding author: kbakrac@hgi-cgs.hr; tel. +385 1 6160706; fax. +385 1 6160799 2department of geology, faculty of science, university of zagreb, horvatovac 95, 10 000 zagreb, croatia doi: 104154/gc.2010.21 geologia croatica 63/3 259–269 3 figs. 2 tabs. zagreb 2010 geologia croaticageologia croatica 1. introduction new results obtained during investigation of the vrhovčak section, located about 2 km west of the town of samobor, at the eastern end of mt. samoborsko gorje are presented. during the middle miocene, the investigated area of mt. samoborsko gorje was located at the south-western margin of the north croatian basin, which represents the south western edge of the pannonian basin system and central paratethys see (fig. 1). formation of the north croatian basin was connected with passive continental rifting. a syn-rift phase began during the ottnangian and lasted until the middle badenian. the post-rift phase lasted from the middle badenian to the pliocene (pavelić, 2001). this positioning within the basin controlled the specifi c evolution of the studied depositional area during the miocene. miocene sediments are most commonly in tectonic contact with mesozoic carbonates, and less often with paleogene rocks which constitute a major part of the core of mt. samoborsko gorje (šikić et al., 1979; vrsaljko et al., 2005). the overlying strata consist of neogene deposits that belong to the ottnangian?, late badenian, sarmatian and early and late pannonian. following the badenian transgression, mt. geologia croatica 63/3geologia croatica 260 samoborsko gorje was submerged, which resulted in a very variable palaeo-relief. this contributed to the contemporaneous deposition of an assortment of different sedimentary facies. apart from breccia and conglomerate deposits, biogenic limestone developed at reefs and the edges of reefs (šikić et al., 1979). marls were deposited in the shelf environment, while silty marls with coal intercalations represent estuarine deposits. according to the geological map (šikić et al., 1979) late badenian sediments occur along the northern and southern sides of samobor. on the northern side, which includes the studied vrhovčak section, badenian sediments appear as erosional remains. however, on the southern side these sediments extend as strip zones up to 4 km in length. biogenic limestones and marls constitute the main parts of these deposits which are rich in macro and micro fossils. in this strip zone, sarmatian and pannonian sediments continuously overlie late badenian sediments. these younger sediments are absent on the northern side of samobor. the investigated locality has previously been known as zaprešić-brijeg in publications, and had been described as a rich community of mollusc fauna. the vrhovčak outcrop represents a geological section with clearly visible, horizontally bedded, sandy limestones, clastic silty marls with coal intercalations in the middle part, and bioclastic limestones in the upper part of the profi le. the fi rst paper dealing with the deposits of zaprešićbrijeg was published by gorjanovićkramberger (1894, 1896). based on faunal remains, he compared them with the deposits of “grund” layers in the vienna basin, which were older and assumed to belong to the “helvetian”. the “grund fauna”, originally defi ned in austria, was developed during the early middle miocene and was widespread within the entire central paratethys (harzhauser et al., 2003). later, šuklje (1929) undertook a detailed investigation of the fauna from this location and compared it to the helvetian fauna from switzerland and the vienna basin, which confi rmed the results of gorjanovićkramberger. pavlovski (1957, 1960) revised and determined the rich community of molluscs from zaprešić-brijeg, which is archived in the samobor museum. she concluded that the fauna from the zaprešić-brijeg matched the “grund” fauna, however the age of the fauna is not “helvetian”, but rather belongs to the early “tortonian” sensu kochansky (1944), (early badenian). bajraktarević (1978) studied the microfossils of mt. samoborsko gorje, and documented the existence of badenian sediments at many locali ties. in the basic geological map šikić et al., (1979) as sig ned these deposits as did gorjanović-kram ber ger (1894, 1896), to the “helvetian” (ottnangian). vrsaljko (2003) on the basis of a rich molluscan community from žum berak mt. and the samoborsko gorje mts., suggested the zonal distribution of miocene sediments. in the grdanjci unit, gravels, silts, and coal intercalations probably represent the products of terrestrial deposition imme diately before the late badenian transgression, but deposits weren’t biostratigraphically investigated in detail. these are special features of this unit as such sediments are not present in other units of žumberak mt. and the samoborsko gorje mts. (vr salj ko et al., 2005). this paper deals with integrated micropalaeontological and petrographic analyses of the vrhovčak section, and provides new results regarding the biostratigraphy and palaeoecology of the investigated sediments. three microfossil groups are present in the sediments in varying abundance: foraminifera, ostracods and palynomorphs (organic walled dinofl agellate cysts or dinocysts, prasinophytes, chlorophycean algae, spores and pollen). figure 1: location map of investigated section vrhovčak. a) geographic location, b) paleoeographic situation in middle badenian, rögl (1998). bakrač et al.: evidence for badenian local sea level changes in the proximal area of the north croatian basin geologia croatica 261 2. study site and methods 2.1. study site the vrhovčak section is located on the eastern slopes of mt. samoborsko gorje (gps n45°48’33”, e15°41’22”), in the vicinity of an access road to local vineyards. the total thickness of the vrhovčak section is around 7.8 m (fig. 2). the lowermost part of the section, where the fi rst sample was taken, has a thickness of 0.45 m and consists of clayey-sandy silt, rich in fossil shell fragments and plant remains. the second layer is 1.90 m thick and is composed of biocalcilutites and calcarenites. samples 2−5 inclusive, were collected from this second layer. rich microfossil assemblages have been discovered and determined in most of these samples. in the middle part of the section, within a total thickness of 1.20 m, silty marls rich in fl oral and faunal remains are intercalated with coal layers. samples 6–9 were collected from these coal-marl layers. clayey limestones with fossil shell fragments occur in the next 0.40 m (sample 10), after which a 1.50 m thick portion of the section is unexposed. the last investigated sample 11 was taken from the uppermost part of the vrhovčak section which consists of a clayey limestone 1.80 m thick. 2.2. methods for the micropalaeontological investigation the collected samples were disaggregated by soaking in a hydrogen peroxide solution for 24 hours, then washed through sieves (0.5; 0.25; 0.125; 0.063 mm) and dried. some of the samples needed extra cleaning and were soaked again in hydrogen peroxide and treated ultrasonically for approximately 20 seconds. 100 g of each dried residue was observed under a stereomicroscope. foraminifera, ostracods and other remains (gastropods, shells, otoliths) were hand-picked, counted and determined. ostracods were picked qualitatively but not selectively, in order to preserve the relative composition of the thanatocenosis. standard palynological processing techniques (faegri & iversen, 1989; moore et al., 1991) were used to extract the organic matter. the samples were treated with sodium pyrophosphate (na4p2o7), hcl (15%), and hf (40%), removing clay minerals, carbonates and silica, followed by separation of the organic residue by means of zncl2 (density>2.0). the residue was sieved at 10 mm using a nylon mesh, mixed with glycerin, and mounted on microscope slides. slides were counted using an olympus bh-2 transmitted light microscope at ´400, ´600 and ´1000 (oil immersion), magnifi cations combined with the interference contrast. a fl uorescence technique was used in order to distinguish reworked palynomorphs. whole slides were counted for palynomorphs. a minimum of 300 palynomorphs (pinus and indeterminable pinaceae excluded) was counted in each sample, if possible. the residues were stored and mounted in silicone oil. photos were taken using a moticam 2300. botanical identifi cation of the pollen grains was carried out and a pollen diagram (fig. 3) plotted using the software c2 version 1.5 (juggins, 2007). figure 2: stratigraphical log of the vrhovčak section. thin sections of collected rock samples were prepared and their composition was determined using a polarization microscope. the 0.09–0.045 mm mineral fraction was separated from the sandy and silty sediments and used for modal analysis after carbonate removal with 4 % cold hydrochloric acid. geologia croatica 63/3geologia croatica 262 qualitative and quantitative analyses were performed by determination of 300–400 grains per sample using the ribbon counting method according to mange & maurer (1992). the caco3 content was determined using a collinson calcimeter (head, 1992). x-ray powder diffraction (xrpd) patterns were recorded using a philips vertical x-ray goniometer (type x`pert) equipped with cu tube, with the following experimental conditions: 45 kv, 40 ma, pw 3018/00 pixcel detector, primary beam divergence 1/4°, continuous scan (step 0.002 º2q/s). the sediment samples, palynological residue and slides are stored in the collection of the croatian geological survey, department of geology, zagreb, croatia, under the collection number vrh-2009. 3. results and discussion 3.1. sediment description based on macroscopic observations, thin section, modal and granulometric analyses and carbonate content, fi ve lithofacies were distinguished in the investigated vrhovčak section: clayey-sandy silt facies, biocalcilutite facies, calcarenite facies, silty marl facies with intercalated coal remains and clayey limestone facies. clayey-sandy silt facies (f1) (sample 1) is 0.45 m thick and is located at the base of the investigated section. it consists of poorly sorted silt with 20% clay and 20% sand content. calcite (60%) dominates the mineral composition. quartz is the second most abundant mineral, followed by lithic fragments and feldspar. among the heavy minerals, the most abundant is dolomite, followed by opaque minerals (pyrite). translucent heavy minerals are sparse, only a few grains of tourmaline, rutile and epidote were determined. biocalcilutite facies (f2) (samples 2−4) is 1.50 m thick and overlies f1. the calcilutite is weakly lithifi ed and in its lowermost part is enriched with sand. the carbonate content ranges from 65% – 80%. besides calcite, the most dominant minerals are dolomite and quartz. potassium feldspars and lithic fragments are represented in smaller amounts. the biocalcilutite is composed of recrystallized microsparite with benthic foraminifera, shell fragments and annelids. calcarenite facies (f3) (sample 5) is 0.40 m thick and can be observed in the middle part of the section. it is weakly lithifi ed and poorly sorted. calcite (around 80%) predominates. marl facies with intercalated coal remains (f4) (samples 7 and 9) is represented in the middle part of the section. it is 120 cm thick. in its lower part the marl has a carbonate content of around 60%, while in the middle and upper part it is enriched in silt, with 30% – 60% carbonate, predominately aragonite, while calcite can be found in smaller amounts. in the lower part of this facies, a few cm thick coal layers are visible. clayey limestones facies (f5) (samples 10, 11) represents the uppermost 3.70 m of the section. microscopically, the sediment can be described as a weakly lithifi ed clayey fi gu re 3 : p al yn om or ph s d is tr ib ut io n in th e vr ho vč ak se ct io n. bakrač et al.: evidence for badenian local sea level changes in the proximal area of the north croatian basin geologia croatica 263 microsparite. recrystallized foraminifera and shell fragments, as well as carbonate grains, were recognized inside the recrystallized microsparitic matrix. the origin of the carbonate grains cannot be determined. siliciclastic detrital grains (quartz, quartzite and feldspars) are less abundant and of silt size dimensions. 3.2. palynomorphs palynomorphs were recorded in all the studied samples, but their preservation varies from poor to good. changes in palynomorph assemblages through the studied section (fig. 3) allow the defi nition of three local zones. generally, the dinocyst assemblages dominate in the lower part (samples 1–5) and in the upper part (samples 10–11). the middle part (samples 6–8) is dominated by sporomorphs and chlorophycean freshwater algae (botryococcus and pediastrum), and sample 9 by prasinophycean algae indicating environmentally unfavourable conditions for most dinofl agellates. lower part of zone i (facies f1-f2; samples 1–4) is marked, beside spiniferites/achomosphaera spp., by batiacasphaera sphaerica stover and spiniferites ramosus (ehrenberg) mantell, indicating a deeper marine environment. this part of the section could be correlated with the uaq zone – unipontidinium aquaeductum (jimenezmoreno et al., 2006). it should be noted that assignment to this zone is considered most likely, although such index fossils as unipontidinium aquaeductum and labyrinthodinium truncatum are absent. the species diversity of the dinofl agellate cysts decreased substantially, indicating a regression (local sea level was lowered), which resulted in unfavourable conditions for the dinofl agellate community. the upper part of zone i (facies f3; sample 5) is marked by cleistosphaeridium placacanthum (deflandre & cookson) eaton et al., spiniferites pseudofurcatus (klumpp) sarjeant and poly sphae ridium zoharyi (rossignol) bujak et al., refl ecting a neritic environment. dominant species in zone ii are pinus, chlorophycean algae (botryococcus, pediastrum) and palynomorphs of unknown origin similar to type 303 (van geel et al., 1981) or mecsekia sp. (but without spines). coal sediments (lower part of facies f4), from which samples 6 and 8 were taken, are of a sapropel type. organic matter is dominated by amorphous liptinite and algae, while spores and phytoclasts generally aren’t represented, which excludes a terrestrial swamp origin for the coal. sample 6 are dominated by botryococcus, but engelhardia pollen is also numerous, indicating evergreen forest in the vicinity. a few marine dinocysts (operculodinium spp.) suggest some marine infl uence. therefore, it can be concluded that the deposits which belong to samples 6 and 8 were deposited in a quiet closed lagoon under the infl uence of marine and fresh water, but without the infl uence of tides and underwater currents. sea level then dropped further. chlorophycean freshwater algae pediastrum (abundant in sample 7), indicate that between the coals, deposition occurred within a freshwater lake, possibly more than 7m deep, with higher ph, and nutrient loading (tyson, 1995). the following plant ecosystems can be distinguished in the pollen data (based on jiménez-moreno, 2006): a coastal marine environment (characterized by the presence of an impoverished mangrove composed of avicennia, mainly accompanied by halophytes such as chenopodiaceae); broad-leaved evergreen forest (engelhardia, taxodiaceae and sapotaceae); evergreen and deciduous mixed forest (quer cus, engelhardia, platycarya, carya, pterocarya, liquidambar, carpinus, celtis and acer); riparian vegetation (salix, alnus, carya, carpinus, zelkova, ulmus and liquidambar); a shrub layer (ericaceae); mid-altitude deciduous and coniferous mixed forest (cathaya and cedrus) and coniferous forest (abies and picea). evergreen trees such as engelhardia, typical of present day rain and evergreen forest at low altitudes, indicates a subtropical climate miocene climatic optimum (jiménez-moreno, 2006). local infl uences cannot be ruled out, but it seems possible that lowstand ser2 of hardenbol et al., (1998) between global cycles tb 2.4 and tb 2.5 (sensu haq et al., 1988) can be seen in this part of the investigated section. kováč et al. (2007) very roughly correlate the early (and “middle”) badenian with the global sea-level changes of the tb 2.3 and tb 2.4 cycles. the tb 2.5 cycle can be regarded as late badenian in age. pavelić (2005) also correlate the lower badenian ncbc 3 cycle with tb 2.3 and tb 2.4 cycles, and the late badenian ncbc 4 cycle with the tb 2.5 cycle. a regional unconformity between syn-rift and post-rift deposits could be a consequence of closure of the seaway to mediterranean in the middle badenian, and can be correlated with sea-level fall at the end of the tb 2.4 cycle (pavelić, 2005). sample 9 (from the upper part of facies f4) is barren of dinocysts, while prasinophycean algae (especially leiosphaeridia) are abundant. prasinophytes are most abundant in the absence of other plankton (tappan, 1980), and are commonly reported to be associated with distinctive water-column features. these usually include low temperature, enhanced productivity and a stratifi ed water column, exhibiting brackish or low-salinity surface waters, overlying low oxygen to anoxic bottom waters (tyson, 1987). the dominan ce of prasinophyte algae has also been recorded from some restricted lagoon and shallow water carbonate facies (tyson, 1995). the late badenian is characterized by stratifi cation of the water column as indicated by the deposition of dysoxic pelites in basinal settings over the entire central paratethyan area (hudáčková et al., 2000). even the platforms became affected by repeated hypoxic events as documented by schmid et al., (2001). harzhauser & piller (2007) correlate this event with global cycle tb 2.5 (sensu haq et al., 1988). probably, such conditions affected the investigated area, because foraminifera are already present, whereas conditions were unfavourable for dinocysts. dinocysts occur in samples 10 and 11, but only a few euryhaline species that are tolerant of lower salinity and water column stratifi cation. prasinophycean algae (especially leiosphaeridia) are still present. the dominant dinocyst species in zone iii (facies f5; samples 10–11) is polysphaeridium zoharyi (rossignol) bujak et al., indicating a warm tropical/subtropigeologia croatica 63/3geologia croatica 264 table 1: distribution of the foraminiferal species within the samples of the vrhovčak section. samples 1 2 4 5 6 7 8 9 10 11 ammonia cf. tepida (cushman) x x ammonia pseudobeccarii (putrja) cf cf x x x x ammonia viennensis (ď orbigny) x x x x x x x x x angulogerina angulosa (williamson) x x x x asterigerinata planorbis (ď orbigny) x x x x x aubignyna sp. x x biapertorbis biaperturatus pokorny x x x x x bitubulogenerina reticulata cushman x x x x bolivina cf. sagitulla didkovskiy x x x x x x bolivina dilatata reuss x x x x bolivina fastigia droogeri cicha & zapletalova x x x x bolivina matejkai cicha & zapletalova x x x bolivina papulata cushman x x x x x bolivina plicatella cushman x x x x x bolivina pokornyi cicha & zapletalova x x x x x bolivina pseudoplicata heron-allen & earland x x x x x x x buccella granulata (di napoli) x x x bulimina aculeata ď orbigny x x x x bulimina elongata ď orbigny x x x x cancris auriculus (fichtel & moll) x x x cassidulina laevigata ď orbigny x x x x coryphostoma digitalis (ď orbigny) x x x cycloforina badenensis (ď orbigny) x x x x x cycloforina contorta (ď orbigny) x x x x x elphidium cf. reussi marks x x x x elphidium macellum (fictell & moll) x x x x x x elphidium rugosum (ďorbigny) x x x x globulina gibba ď orbigny x x x x globulina spinosa ď orbigny x x x x hanzwaia boueana (ď orbigny) x x x x x x heterolepa dutemplei (ď orbigny) x x x x x x x islandiella punctata (reuss) x x x x lenticulina inornata (ď orbigny) x x x lobatula lobatula (walker & jacob) x x x x nonion commune (ď orbigny) x x x x x x x x nonion tumidulus pishvanova x x x nonionides sp. x x porosononion granosum (ď orbigny) x x x x quinqueloculina akneriana ď orbigny x x x x reussella spinulosa (reuss) x x x x x x rosalina spp. x x x sinoloculina consobrina (ď orbigny) x x x x x texstularia gramen ď orbigny x x trifarina bradyi cushman x x x x virgulopsis tuberculatus (egger) x x x x species bakrač et al.: evidence for badenian local sea level changes in the proximal area of the north croatian basin geologia croatica 265 cal setting with sub-normal salinity. p. zoharyi has been recorded from subtropical and tropical regions, generally in coastal sites near upwelling cells and river mouths. the highest relative abundances have been found in tropical low-salinity areas, where this species can dominate the associations (marret & zonneveld, 2003). lingulodinium machaerophorum (deflandre & cookson) wall is considered to be a temperate to tropical, coastal species distributed within a very broad salinity range (from brackish to fully marine environments). blooms of l. polyedrum can be related to high nutrient input and warm, stratifi ed surface water conditions (marret & zonneveld, 2003). be c ause of the only ecological character of this assemblage, this zone couldn’t be correlated with any palynostratigraphic zones. decreasing salinity and water depth caused loss of diversity. thermophilic dinofl agellate species such as l. machaerophorum, p. zoharyi, and m. choanophorum, indicate subtropical conditions for the lower and upper part of the section (marret & zonneveld, 2003). also, pollen of thermophilous evergreen trees such as engelhardia suggest a subtropical climate. fluvial systems occurred along the coastline, transporting both terrestrial pollen grains and freshwater algae out to the marine depositional area. based on palynomorphs, the vrhovčak section could be correlated with the hidas-53 core in hungary. the middle part of the hidas-53 borehole (hidas lignite formation) is considered as middle badenian in age. the lower part of the succession (limestone) contains mostly marine plankton with less sporomorphs. further upwards there are lignite beds with freshwater algae. pollen of subtropical swamp forest dominates the sample above the lignite. microforaminifera reappear at the top, indicating a transgression. the maximum temperature was 20°c, minimum 13.6°c, mean 17.2°c (nagy, 2005). similar results are presented in jiménezmoreno (2006) where vegetation from the hidas-53 core is compared with present day fl oras of se china. he also explained that the reduction in thermophilous plants and increase of mesothermic–deciduous and altitude trees as represented in the pollen spectra, could be caused by northward drifting of the euroasiatic plate, and the modifi cation of the ocean heat transport from an antiestuarine situation to estuarine conditions in paratethys. formation of the lagoon or bay is also documented in the sw part of medvednica mt. as a consequence of the proximity of the dinarides (representing land), while an open marine environment existed in the ne, closer to the central part of central paratethys (avanić et al., 2003; vrsaljko et al., 2006; ćorić et al., 2009). 3.3. foraminifera the lower part of the vrhovčak section (samples 1, 2 and 4) contains badenian benthic foraminiferal assemblages in which the prevailing species are ammonia viennensis and nonion commune (tab.1). in sample 4, the common species are heterolepa dutemplei, hanzawaia horčici and the agglutinated species textularia gramen. other species are represented by only a few individuals. in sample 5, the diversity of benthic foraminifera decreases in relation to the fi rst three samples, but new species appear such as ammonia pseudobeccarii, a. cf. tepida, nonionides sp., nonion tumidulus and aubignyna sp. (sensu rupp, 1986). poorer foraminiferal assemblages were discovered in samples 7-9. sample 10 features an increasing number of species and individuals (especially a. viennensis and n. commune). however, in sample 11, assemblages with higher diversity and quantities of benthic foraminifera occur (especially a. viennensis and cancris auriculus). in samples 1, 2, 4 and 11 only a few individual planktonic foraminifera were observed including: globigerinoides trilobus (reuss), globo quadrina cf. altispira (cushman & jarvis), globi gerinella cf. obesa (bolli), globorotalia bykovae (aisenstat), tenuitellinata sp. and orbulina suturalis bronniman. the foraminiferal assemblages in samples 1, 2, 4 and 11 are characterized by ammonia viennensis, nonion commune, heterolepa dutemplei, lobatula lobatula, porosononion granosum, elphidium-group and miliolid species. according to rögl & spezzaferri (2003) and spezzaferri (2004), this assemblage is characteristic of shallow water environments. in addition, the ammonia group and the species nonion commune are resistant to reduced salinity according to rupp (1986) and wenger (1987). samples 1, 2, 4, 10 and 11 display rich assemblages. we can conclude that the sediments of vrhovčak were deposited in a shallow water environment; eventually the species of ammonia and nonion group had been transported from the shallow part to the inner part of the shelf with tiny benthic foraminifera (table 1). reduced foraminiferal assemblages in samples 7–10 consist of ammonia, nonion, aubignyna and miliolids which indicate a reduction in salinity (rögl, 1998). freshwater ostracods have also been detected in these samples. the assemblages of benthic foraminifera in the samples from the vrhovčak section belong to the badenian. considering that planktonic specimens are rare and foraminifera such as uvigerina and lagenids, that characterize deeper environments and are zone markers of the badenian layers in the paratethys (grill, 1941; papp & turnovsky, 1953; papp et al., 1978) have not been found, it is diffi cult to determine the chronostratigraphy of the studied section in more detail. although the presence of orbulina suturalis bronniman in sample 1, confi rmed that the investigated deposits are younger than 14.74 ma (based on rögl et al, 2008) or even 14.56 ma (based on hohenegger et al, 2009). 3.4. ostracods ostracods were studied in ten samples from the vrhovčak section. altogether, 29 species belonging to 22 genera were identifi ed. one genus and fi ve species remain in open nomenclature. the complete fauna is listed in table 2. the maximum numbers of species (14) was discovered in sample 4. sample 7 also had a relatively high number of species (10). in samples 1, 5, 10 and 11, the number of species varies between 5 and 9. two samples, (2 and 9) each geologia croatica 63/3geologia croatica 266 contain 3 species. sample 8 only has 1 species. in sample 6, ostracods were not recorded. the selected taxa were divided into two palaeoecological groups. the main ostracod group consists of a typical marine ostracod fauna, and has been identifi ed at the base (samples 1, 2, 4, 5) and at the upper part of the section (samples 9, 10, 11). in most of the samples, the marine faunal assemblage is dominated by three species: cytheridea acuminata, olimfalunia plicatula and olimfalunia spinulosa. several other species, which also occur in marine sediments, are most abundant and prominent but in different samples: phlyctenophora affi nis, phlyctenophora farkasi, aurila angulata, a. haueri, a. punctata, a. cf. galeata for sample 4; pontocythere curvata and carinocythereis carinata for sample 5; costa edwardsi for sample 10 and aurila sp. for sample 11. seven species occur in different samples with a single valve: nonurocythereis seminulum, hermanites haidingeri, loxocorniculum hastaum, loxoconcha sp., parakrithe sp., urocythereis kostlenis and xestoleberis sp. a second ostracod group, occurring only in samples 7 and 9, is represented by freshwater species mixed with respective marine ostracod fauna. the dominance of freshwater ostracod species in the second group indicates a general change in the environment. the dominant species vestalenula cylindrica in the second group appears exclusively in sample 7 (more than 40 valves). together with one single remnant of paralimnocythere rostrata, eucypris sp. and parts of valves that belong to cypridoidea gen. et sp. indet. it represents the freshwater ostracod fauna in sample 7. cypridoidea gen. et sp. indet. has also been found in sample 9. the accompanying species to the freshwater ostracod fauna are very small numbers of marine ostracods such as aurila haueri, carinocythereis carinata, cytheridea acuminata, nonurocythereis seminulum, table 2: distribution of the ostracod species within the samples of the vrhovčak section. only adult valves for each species in the samples were counted: � 1-5, � 5–10, � 10–20, � 20–50. ostracod species 1 2 4 5 6 7 8 9 10 11 aurila angulata (reuss) � � no o st ra co ds � aurila cicatricosa (reuss) � aurila cf. galeata (reuss) � aurila haueri (reuss) � � � aurila punctata (münster) � � aurila sp. � carinocythereis carinata (roemer) � � � � cnestocythere lamellicosta triebel � costa edwardsi (roemer) � cytherella compressa (münster) � cytheridea acuminata bosquet � � � � � � � nonurocythereis seminulum seguenza � hermanites haidingeri (reuss) � loxocorniculum hastaum (reuss) � loxoconcha sp. � olimfalunia plicatula (reuss) � � � � � olimfalunia spinulosa (reuss) � � � � parakrithe sp. � phlyctenophora affi nis (schneider) � � phlyctenophora farkasi (z alanyi) � � � pokornyella deformis (reuss) � pontocythere curvata (bosquet) � semicytherura cf. acuticostata (schneider) � � urocythereis kostlenis (reuss) � xestoleberis sp. � vestalenula cylindrica (strauss) � cypridoidea gen.et sp. indet. � � paralimnocythere rostrata (straub) � eucypris sp. � samples bakrač et al.: evidence for badenian local sea level changes in the proximal area of the north croatian basin geologia croatica 267 olimfalunia spinulosa, phlyctenophora farkasi and urocythereis kostelensis. it is possible to assume that sample 8 with only one registered single valve of cytheridea acuminata and sample 6, barren of ostracods, belong to the second group of samples and represent a phase of environmental changes, in which living conditions were not favourable for ostracods. freshwater ostracods are always accompanied by freshwater microgastropods. the ostracod study did not provide detailed biostratigraphical indications, since most of the determined ostracods are wide-ranging taxa. in the north croatian basin these species are recorded from badenian sediments and older stratigraphic horizons. the presence of olimfalunia spinulosa would assign the deposits of vrhovčak to the ostracod biozone no-8 (middle badenian) after jiřiček (1983). in addition, the presence of carinocythereis carinata and phlyctenophora farkasi zonal markers for ostracod biozone no-10 (the uppermost badenian) starting from sample 4 allow dating of this level as upper badenian (jiřiček, 1983; jiriček & riha, 1990). the ostracod zonations should be treated with caution, because some new results in ostracod research have extended the stratigraphic distribution of several species (zorn, 2003). palaeoecological data obtained from ostracod analysis are much more interesting. most of the genera recorded from the vrhovčak section are globally widespread, but their presence has ecological implications. generally, the marine ostracod fauna refl ects a shallow water environment. among genera and species which are more characteristic of deeper infraneritic to bathyal environments only parakirthe sp. was found in sample 4. ostracod genera cytheridea, aurila, callistocythere, loxoconcha and xestoleberis are characteristic for upper infralittoral and epineritic facies. in the middle part of the section, well preserved and numerous freshwater ostracod species with few marine ostracods have been recorded. this indicates that freshwater ostra cod fauna are autochthonous and the marine single specimens must have been transported into freshwater sediments. the population structure indicates low water energy and low sedimentation rates in the environment (whatley, 1983). the preservation of the marine ostracods in the lower part of the section (samples 1, 2, 4 and 5) is very good and for several species larval stages are also documented. from this point of view the fauna seems to be largely autochthonous. from sample 9 to the upper parts of the section, the increasing number of carapaces of marine ostracods in relation to valves, indicates changes in the energy of the environment and sedimentation rates. 4. conclusion biostratigraphical, palaeoecological and micropalaeontological investigations of foraminifera, ostracods and palynomorphs have been carried out in the badenian vrhovčak section. the diversity in facies and faunistic composition of the investigated sediments allows recognition of biotic events and the reconstruction of environmental change during the badenian. the sediments from the investigated section are a result of deposition of suspended clayey-micrite material and redeposited carbonate fossil fragments in a shallow marine environment, with a weak input of terrigenous material. the coal remains indicate occasional sea level regressions and freshwater infl uence. marine sediments of badenian age at the base and upper parts of the section have been documented with phytoplankton (organic walled dinofl agellate cysts and prasinophyte algae), benthic foraminifera and ostracods. palynomorphs in the lower part of the investigated deposits indicate a deeper marine environment. species diversity of dinofl agellate cysts decreased substantially in the lower part, indicating a regression (local sea level was lowered) and neritic environment. generally the foraminiferal and ostracod fauna from the marine sediments of the section (the lower and upper parts) refl ected a shallow water environment. few planktonic foraminifera and the deeper ostracod species parakrithe sp. indicate the existence of occasional communication with the open sea and penetration of deep water fauna. in the middle part of the vrhovčak section, layers of coal and freshwater sediments appear. in the freshwater sediments (total thickness 0.2 m) the foraminiferal assemblage is less diverse, freshwater ostracods, mixed with a few marine ostracods and freshwater microgastropods. the coal sediments are of the sapropel type, and were deposited in a quiet closed lagoon under the infl uence of marine and fresh water, but without the infl uence of tides and underwater currents. between the coal horizons, deposition occurred in a freshwater lake, possibly with depths greater than 7m, higher ph, and nutrient loading. the upper part of the section starts with the dominance of prasinophyte algae refl ecting restricted lagoon and shallow water carbonate facies, enhanced productivity and a stratifi ed water column (exhibiting brackish or low-salinity surface waters overlying low oxygen to anoxic bottom waters). later in the section, dinocysts are represented along with prasinophycean algae, but only a few euryhaline species that are tolerant to decreasing salinity and water column stratifi cation. the climate was believed to be subtropical during deposition of the section material based on palynological evidence. thermophilic dinofl agellate species indicate subtropical conditions for the lower and upper part of the section, while pollen of thermophilous evergreen trees suggest a subtropical climate for the middle part. fluvial systems occurred along the coastline, transporting both terrestrial pollen grains and freshwater algae out to the marine depositional area. the sediments from the base of section (samples 1–5) could be correlated to cycle tb 2.4 of the main badenian transgression that affected the entire central paratethys. it is followed by a regression, and lowstand ser2 of hardenbol et al. (1998), presumed for the middle part of the secgeologia croatica 63/3geologia croatica 268 tion (samples 6–8). finally, sediments from the upper part of section (samples 9–11) belong to the late badenian cycle tb 2.5 (sensu haq et al., 1988). acknowledgment the authors wish to thank colleagues mato brkić, davor vrsalj ko and radovan avanić who participated in the fi eld investigation. the present investigation is part of the basic research that was supported by the croatian geological survey, department of geology, and ministry of science, education and sports project no. 181-1811096-1093: „basic geological map of the republic of croatia 1:50.000“. for improvement of the english text we warmly thank borna lužar-oberiter. we are grateful to mathias harzhauser for useful suggestions on the earlier version of the paper, and to stjepan ćorić and gonzalo jiménez-moreno for their valuable and helpful reviews. references avanić, r., kovačić, m., pavelić, d., miknić, m., vrsaljko, d., bakrač, k. & galović, i. (2003): the middle and upper miocene facies of mt. medvednica (northern croatia).− in: vlahović, i. & tišljar, j. (eds.): evolution of depositional environments from the palaeozoic to the quaternary in the karst dinarides and the pannonian basin. 22nd ias meeting of sedimentology, opatija – september 17–19, 2003, field trip guidebook, 167–172. bajraktarević, z. (1978): gornjotortonska starost sedimenata zapre šić-brijega [upper tortonian sediments of zaprešić-brijeg near samobor, north croatia − in croatian].− geol. vjesnik, 30/1, 63−69. ćorić, s., pavelić, d., rögl, f., mandic, o., vrabac, s., avanić, r. & vranjković, a. (2009): revised mid miocene datum for initial marine fl ooding of north croatian basins (pannonian basin system, central paratethys).− geol. croat., 62/1, 31−43. faegri, k. & iversen, j. (1989): textbook of pollen analysis. (4th edition by faegri, k., kaland, p.e. & krzywinski, k.).− john wiley & sons new york, 328 p. gorjanović-kramberger, d. (1894): geologija gore samoborske i žumberačke [geology of samoborska gora mt. and the žumberak mt. − in croatian].− rad jazu, 120, 1−82. gorjanović-kramberger, d. (1896): über das vorkommen der pereiraia gervaisii vez. sp. in croatien.− verhandlungen der k. k. geologischen reichsanstalt, 1−18, 142 143. grill, r. (1941): stratigraphische untersuchungen mit hilfe von mikrofaunen im wiener becken und den benachbarten molasse anteilen.− öl kohle, 31, 595−603. haq, b.u., hardenbol, j. & vail, p.r. (1988): mesozoic and cenozoic chronostratigraphy and cycles of sea level changes.− in: wilgus, c.k., hastings, b.s., kendall, c.g.st.c., posamentier, h. w., ross, c.a. & van wagoner, j.c. (eds.): sea-level changes an integrated approach.− semp special publications, 42, 71−108. hardenbol, j., thierry, j., farley, m.b., jacquin, t., de graciansky, p.c. & vail, p.r. (1998): mesozoic and cenozoic sequence chronostratigraphic framework of europeau basins.− in: graciansky, p.c., hardenbol, j., jacquin, t. & vail, p.r. (eds.): mesozoic and cenozoic sequence stratigraphy of european basins.− sepm special publications, 60, 3−13. harzhauser, m., mandic, o. & zuschin, m. (2003): changes in paratethyan marine molluscs at the early/middle miocene transition: diversity, palaeogeography and palaeoclimate.− acta geol. pol., 53/4, 323−339. harzhauser, m. & piller, w.e. (2007): benchmark data of a changing sea palaeogeography, palaeobiogeography and events in the central paratethys during the miocene.− palaeogeogr. palaeocl., 253, 8–31. doi:10.1016/j.palaeo.2007.03.031 head, k.h. (1992): manual of soil laboratory testing.− pentech press london, 253−260. hohenegger, rögl, f., ćorić, s, pervesler, p., lirer, f., roetzel, r., scholger, r. & stingl, k. (2009): the styrian basin: a key to the middle miocene (badenian/langhian) central paratethys transgressions.− austrian journal of earth sciences, 102, 102−132. hudáčková, n., holcová, k., zlinská, a., kováč, m. & nagymarosy, a. (2000): paleoecology and eustasy: miocene 3rd order cycles of relative sea-level changes in the western carpathian − north pannonian basins.− slovak geological magazine, 6, 95−100. jiménez-moreno, g. (2006): progressive substitution of a subtropical forest for a temperate one during the middle miocene climate cooling in central europe according to palynological data from cores tengelic-2 and hidas-53 (pannonian basin, hungary).– rev. palaeobot. palyno., 142, 1–14. doi:10.1016/j.revpalbo.2006.05.004 jiménez-moreno, g., head, m.j. & harzhauser, m. (2006): ear ly and middle miocene dinofl agellate cyst stratigraphy of the cen tral paratethys, central europe.− j. micropalaeontol., 25, 113–139. jiřiček, r. (1983): redefi nition of the oligocene and neogene ostracod zonation of the paratethys.− miscellania micropalaeontologica, 4, 195−236. jiřiček, r. & riha, j. (1990): correlation of ostracod zones in the paratethys and tethys.− saito ho-on kai spec. pub. 3 (proceedings shallow tethys 3, sendai, 1990), 435–457. juggins, s. (2007): c2 version 1.5: software for ecological and palaeoecological data analysis and visualisation [program]. newcastle upon tyne: university of newcastle. kováč, m., andreyeva-grigorovich, a., bajraktarević, z., brzobohatý, r., filipescu, s., fodor, l., har zhau ser, m., nagymarosy, a., oszczypko, n., pavelić, d., rögl, f., saftić, b., sliva, ľ. & studencka, b. (2007): badenian evolution of the central paratethys sea: paleogeography, climate and eustatic sea level changes.– geol. carpath., 58, 579−606. marret, f. & zonneveld, k.a.f. (2003): atlas of modern organic-walled dinofl agellate cyst distribution.− rev. palaeobot. palyno., 125/1−2, 1−200. doi:10.1016/s0034-6667(02)00229-4. kochansky-devidé, v. (1944): fauna marinskog miocena južnog pobočja medvednice–zagrebačke gore (mio-zäne marine fauna des sudlichen abhanges der medved nica, zagreber gebirge) [fauna of marine miocene of southern fl anks of the medvednica mt. and the zagre-bačka gora mt. – in croatian and german].– vjestnik hrv. drž. geol. zavoda i hrv. drž. geol. muzeja, 2/3, 171–272. menge, m.a. & maurer, h.f.w. (1992): heavy minerals in colour.− chapman & hall, london, 1−151. moore, p.d., webb, j.a. & collinson, m. (1991): pollen analysis (second edition).− blackwell sci. publication, london, 216 p. nagy, e. (2005): palynological evidence for neogene climatic change in hungary.− occasional papers of the geological institute of hungary, 205, 1−120. papp, a., cicha, i. & ctyroka, j. (1978): allgemeine charakteristik der foraminiferenfauna im badenien.− in: brestenska, e. (ed.): chronostratigraphie und neostratotypen, bd.vi (veda) 236−268. papp, a. & turnovsky, k. (1953): die entwicklung der uvigerinen im vindobon (helvet und torton) des wiener becken.− jahrbuch der geologischen bundesanstalt, 96, 117−143. pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.− basin research, 13, 359−376. bakrač et al.: evidence for badenian local sea level changes in the proximal area of the north croatian basin geologia croatica 269 pavelić, d. (2005): cyclicity in the evolution of the neogene north croatian basin (pannonian basin system).− in: j.m. mabesoone & v.h. (eds.): neumann cyclic development of sedimentary basins. developments in sedimentology, 57, 273−283. pavlovsky, m. (1957): prilog poznavanju miocenskih gastropoda zaprešić-brijega kraj samobora (ein beitrag zur kenntnis mionzäner gastropoden von zaprešić-brijeg bei samobor) [a contribution to knowledge on miocene gastropods of zaprešić brijeg nearby samobor in croatian and german].– geol. vjesnik, 10, 51−55. pavlovsky, m. (1960): novi elementi faune zaprešić-brijega kraj samobora (neue elemente der fauna von zaprešić-brijeg bei samobor) [new elements within fauna of locality zaprešić brijeg, nearby samobor − in croatian and german].− geol. vjesnik, 13, 213−216. rögl, f. (1998): foraminiferenfauna aus dem karpat (unter – miozän) des korneuburger beckens.− beiträge zur paläontologie, 23⁄1, 123−173. rögl, f. & spezzaferri, s. (2003): foraminiferal paleoecology and biostratigraphy of the mülbach section (gaindorf formation, lower badenian), lower austria.− annalen des naturhistorischen museums in wien, 104 a, 23−75. rögl, f., ćorić, s., harzhauser, m., jiménez-moreno, g., krohn, a., schultz, o., wessely, g. & zorn, i. (2008): the middle miocene badenian stratotype at baden-sooss (lower austria).− geol. carpath., 59, 367−374. rupp, ch. (1986): paläoökologie der foraminiferen in der sandschalerzone (badenien, miozän) des wiener beckens.− beiträge zur paläontologie, 12/41, 1−180. schmid, h.p., harzhauser, m. & kroh, a. (2001): hypoxic events in a middle miocene carbonate platform of the central paratethys (austria, badenian, 14 ma).− annalen des naturhistorischen museums wien, 102a, 1−50. spezzaferri, s. (2004): foraminiferal paleoecology and biostratigraphy of the grund formation (molasse basin, lower austria).− geol. carpath., 55⁄2, 155−165. šikić, k., basch, o. & šimunić, a. (1979): osnovna geološka karta sfrj 1:100 000. tumač za list zagreb l33-80 [basic geological map of sfrj 1:100.000. geology of the zagreb sheet − in croatian].− institut za geološka istraživanja zagreb (1972), savezni geološki zavod, beograd, 81 p. šuklje, f. (1929): mediteranska fauna zaprešić-brijega u samoborskoj gori [mediterranean fauna in zaprešić brijeg location in the samoborska gora mt. − in croatian].− vijesti geološkog zavoda, 3, 1−52. tappan, h. (1980): the paleobiology of plant protists.– san francisco, ca, freeman, 1028 p. tyson, r.v. (1987): the genesis and palynofacies characteristics of marine petroleum source rocks.− in: brooks, j. & fleet, a.j. (eds.): marine petroleum source rocks, geol. soc. spec. publ., 26, 47–67. tyson, r.v. (1995): sedimentary organic matter. organic facies and palynofacies.− chapman & hall, london, 615 p. van geel, b., bohncke, s.j.p. & dee, h. (1980–1981): a palaeoecological study of upper late glacial and holocene sequence from “de borchert”, the netherlands.− rev. palaeobot. palyno., 31, 367–448. vrsaljko, d. (2003): biostratigrafi ja miocenskih naslaga žum beračkog i samoborskog gorja na temelju mekušaca [biostratigraphy of the miocene deposits from the žumberak mt. and samoborsko gorje mts. on the basis of molluscs – in croatian with an english abstract].– unpubl. phd thesis, university of zagreb, 143 p. vrsaljko, d., pavelić, d. & bajraktarević, z. (2005): stratigraphy and palaeogeography of miocene deposits from the marginal area of žumberak mt. and samoborsko gorje mts. (northwestern croatia).− geol. croat., 58/2, 133–150. vrsaljko, d., pavelić, d., miknić, m., brkić, m., kovačić, m., hećimović, i., hajek-tadesse, v., avanić, r. & kurtanjek, n. (2006): middle miocene (upper badenian/sarmatian) palaeoecology and evolution of the environments in the area of medvednica mt., (north croatia).− geol. croat., 59/1, 51−63. wenger, w.f. (1987): die foraminiferen des miozäns der bayerischen molasse und ihre stratigraphische sowie paläographische auswertung.− zitteliana, 16, 173−340. whatley, r.c. (1983): the application of ostracoda to paleoenvironmental analysis.− in: maddocks, r. (ed.): applications of ostracoda. proc. 8th int. symp. ostracoda, univ. houston, tex., 51−77. zorn, i. (2003): ostracoda from the gaindorf formation (middle miocene, lower badenian) of mühlbach (molasse basin, lower austria).− annalen des naturhistorischen museums in wien, 104 a, 77−84. manuscript received march 05, 2010 revised manuscript accepted june 25, 2010 available online november 11, 2010 kovacic.indd � ab stra ct multiple discriminant analysis (mda) of upper miocene and pliocene sands of the sw portion of the pannonian basin system was performed in order to determine the optimum criteria for separating the previously defi ned informal lithostratigraphic units – ozalj, andraševec, hum zabočki, cernik and pluska. the heavy mineral association is employed as independent variables, or descriptors, in the process of discrimination and results of analysis established a clear and strong bond between characteristic heavy mineral assemblages in the upper miocene and pliocene sands and their affi nity to particular lithostratigraphic units. in this respect, the pluska unit is especially highlighted, followed by the ozalj and hum zabočki units. close heavy mineral/lithostratigraphic unit relationships were very useful in unravelling the basic sedimentological meaning hidden beneath specifi c discriminant functions in the mathematical model. the most prominent is df1 accounting for almost 3/4 of the total variance of the investigated sedimentary system. in accordance with its 'key' mineral it is labeled kyanite function which indicates the (metamorphic) provenance of the siliciclastic mineral detritus. the second most important, df2, is labeled garnet-zircon function and, being bipolar, it points at both provenance of siliciclastic material (older sedimentary rocks) and hydraulic conditions during the transport and sedimentation of the detritus. finally, df3 is of minor importance indicating the stability of the heavy mineral association in sandy sediments. three lithostratigraphic units, namely ozalj, pluska and hum zabočki are clearly separated by the functions labeled after their distinctive ('key') heavy minerals. keywords: discriminant function analysis, heavy mineral association, lithostratigraphic units, upper miocene, pannonian basin system discriminant function analysis of upper miocene and pliocene sands from the southwestern part of the pannonian basin system, croatia � marijan kovačić1, zoran peh2 and anita grizelj2 1 university of zagreb, faculty of science, horvatovac 95, hr-10000 zagreb, croatia; (mkovacic@geol.pmf.hr) 2 croatian geological survey, sachsova 2, hr-10000 zagreb, croatia; (zpeh@hgi-cgs.hr; agrizelj@hgi-cgs.hr) doi: 10.4154/gc.2009.12 geologia croaticageologia croatica 1. introduction the pannonian basin system (pbs) is a system of back-arc basins the evolution of which started in the early miocene epoch as a response to continental collision and subduction of the european platform below the apulian platform (royden, 1988; horváth, 1995; kováč et al., 1998). surrounded by the alps, carpathians and dinarides (fig. 1), it included a number of different sized, deep, depressions and basins separated by a comparatively shallow complex of basement rocks (horváth & royden, 1981; royden, 1988). the fi rst phase of basin development was characterized by tectonic thinning of the crust and isostatic subsidence (syn-rift), while the second phase was marked by the geologia croatica 62/3 189–200 4 figs. 4 tabs. zagreb 2009 geologia croatica 62/3geologia croatica 190 fi ned groups following the principle of least distance (greatest similarity). this being so, the main scope of this work is defi ned as follows: a) to determine the strength of the relationship between the composition of the hma of the studied sands and their lithostratigraphic affi liation after the method of multiple (multi-group) discriminant analysis (mda) has been applied; b) to decide which minerals contribute most to discrimination between the lithostratigraphic units, and; c) to answer to what extent discrimination between individual groups facilitates interpretation of geological events. 2. lithostratigraphic units, facies, and sedimentary environments the investigated area is situated in the central and eastern parts of the republic of croatia. it consists of three different and geographically separated regions over about 200 km distance – hrvatsko zagorje with the medvednica mt., žumberak mt., and slavonian mts. (fig. 2). during the systematic fi eldwork that included surface geological mapping, subject to the requirements of the basic geological map of croatia 1:50000, the upper miocene and pliocene sediments were divided into six informal lithostratigraphic units, namely the croatica (cro), medvedski breg (meb), ozalj (oza), andraševec (and), hum zabočki (hzb), pluska (plu), and cernik (cer) units. in the slavonian mts., the meb unit was, however, referred to as the pavlovci unit while simultaneously the designation nova gradiška unit is applied to the hzb unit by some researchers (kovačić et al., 2005). their stratigraphic position and inter-correlation is displayed in fig. 3. and their description is accepted from the works of vrsaljko (2003), kovačić (2004) and kovačić & grizelj (2006). in contrast to the widely accepted lithostratigraphic nomenclature in this part of the pbs, which is defi ned basically according to the results of subsurface geological investigations (šimon, 1973, 1980; cessation of rifting and subsidence caused by cooling of the lithosphere (post-rift) (horváth & royden, 1981; royden et al., 1983; royden, 1988). in the south western part of the pbs the syn-rift phase lasted from the ottnangian to the middle badennian, while the post-rift phase extended from the middle badennian to the end of the pontian (pavelić, 2001). palaeogeographically, the pbs extended over the major part of central paratethys – a sedimentary basin having passed through a succession of stages of isolation and reconnection to the open oceans (indopacifi c and mediterranean) during its evolution. the fi nal isolation at the end of the middle miocene resulted in development of lake pannon that existed as a separate sedimentary basin during the late miocene (rögl & steininger, 1983; rögl, 1998; 1999; magyar et al., 1999). from the upper miocene to the lower pliocene, great quantities of clastic detritus were transported to the southwestern part of the pbs from both the surrounding mountain ranges and the uplifted areas within the basin itself (šćavnićar, 1979; šimunić & šimunić, 1987; kovačić et al., 2004; kovačić & grizelj, 2006; grizelj et al., 2007), triggering the submersion that marked the onset of compressional tectonics in basin development (jamičić, 1995; tomljenović & csontos, 2001; marton et al., 2002), and the subsequent gradual and diachronous infi lling of lake pannon (magyar et al., 1999; kovačić et al., 2004). in earlier research work, the upper miocene and plio cene sedimentary rocks of the southwestern part of the pbs were typically divided according to their endemic fossil assemblages (e.g. šikić et al., 1979; basch, 1983). however, according to the recent geological investigations related to the basic geological map of the republic of croatia 1:50000, a number of informal lithostratigraphic units were distinguished among the investigated sedimentary rocks, based principally on the fi eld observations of their lithological characteristics. a considerable body of data was thus created including the modal composition of sands, which represent the most important lithological member of the newly established units. such a large amount of numerical data is quite a propitious material for a statistical procedure which employs various multivariate methods and techniques. one of the most often exploited tools in geosciences is discriminant function analysis which is used to compare a number of groups for which there already exists a sound (geological) basis for separation. for instance, here, lithostratigraphic units can serve as á priori established geological groups to which the collected geological objects (samples) can be assigned using some independent geological criterion such as geological mapping (rock, 1988). a key problem in the study can be summarized in a simple question: can such predefi ned groups be distinguished effectively utilizing the selected suite of known attributes in each sample such as, for example, the heavy mineral association (hma), or subtle differences in the mineral composition that can disturb the homogeneity of groups acknowledged on ‘coarser’ geological criteria derived from geological mapping, and cause them to overlap signifi cantly? it may also be important to allocate each new ‘unknown’ object (sample) to one of the previously defigure 1: the pannonian basin system and its surroundings (after royden, 1988). the area delineated is in the south-western part of the pannonian basin system, shown in fig. 2. kovačić et al.: discriminant function analysis of upper miocene and pliocene sands from the southwestern part of the pannonian basin system, croatia geologia croatica 191 velić, 1980), these units are informal in character. however, some recent investigations could easily assign them a rank of formation (kovačić, 2004). the cro unit (lower pannonian) occurs in the region of hrvatsko zagorje and the slavonian mts. the sharp boundary with the underlying sarmatian beds is conformable, while the lateral-vertical transition to the younger meb and oza units is gradual (fig. 3). it is composed of thin-bedded clayey limestones and marls with occasional intercalations of calcareous sands deposited in a shallow water lacustrine environment of low salinity. the oza unit (lower–middle pannonian) is widespread on the žumberak and medvednica mountains, unconformably overlying the middle miocene and older deposits, or occurring as the lateral equivalent of the cro unit and the lower part of the meb unit. it consists of medium-grained clastic sedimentary material deposited in coastal lacustrine, fl uvial, or distributary channel environments. the variability of locally derived clastic detritus clearly indicates the diverse composition of the parent rocks in the area. the meb unit (lower pannonian–upper pontian) is present over the entire investigated area. it conformably overlies the cro and oza units or sarmatian deposits consisting mostly of marls deposited in the deep-water brackish environment (fig. 3). sands and gravels are interbedded within the lowermost parts of the unit, along the contact with the oza unit, the composition and origin of which correspond closely to the underlying oza clastics. figure 2: the south-western part of pannonian basin system with location of the study-area (hrvatsko zagorje, mt. medvednica, mt. žumberak and slavonian mts.). figure 3: schematic geological sections of the upper miocene deposits with informal lithostratigraphic units of hrvatsko zagorje, mt. medvednica, mt. žum berak and the slavonian mts. strati graphic position of the litostratigraphic units is based on changes of endemic fauna, so it is highly speculative. geologia croatica 62/3geologia croatica 192 the and unit (lower pannonian–upper pontian) covers the entire study area. this unit conformably overlies the meb unit and is also conformably overlain by the hzb unit. it is composed of alternating layers of sands, silts and marls deposited in the prodelta-deltaic slope lake environment. siliciclastic detritus is mineralogically and structurally relatively mature. its composition is homogeneous over the entire area and derives its origin mostly from metamorphic and older sedimentary rocks outcropping in the source area relatively far to the north. the hzb unit (upper pontian) is widespread in the whole studied area, overlying conformably the older, and unit, and passing conformably upward into the overlying cer and plu units (fig. 3). it is characterized by alternation of sand and silt beds deposited in the delta front in the shallow brackish lacustrine environment. according to both composition and origin of its detritus it is not signifi cantly different from the and unit. the plu unit (upper pontian–pliocene) crops out in hrvatsko zagorje and in the žumberak mts. overlying conformably the hzb unit, while its upper boundary remains undetermined. it consists of clays, silts and sands with lenses of gravel and coal deposited in a river or distributary channels, alluvial plains, coastal lagoons and swamps. the clastic detritus is comparatively mature in a mineralogical and structural sense, and is similar in composition to the detritus of the and and hzb units. the latter two differ in their hma, indicating some variations in the composition of the parent rocks. the cer unit (lower pliocene) is detected only in the slavonian mts. region, overlying the hzb unit (fig. 3). it consists of clays, silts and sands with lenses of gravel deposited in a sedimentary environment similar to that of the plu unit. the composition and origin of detritus is close to the and and hzb units. 3. methods 3.1. sampling, sample preparation and analysis a total of 101 samples were collected during the fi eld investigations that included geological mapping and construction of the geological columns of unbound sand-silt sedimentary material. sampling was designed to cover the entire study area, comprising all relevant time periods and investigated informal lithostratigraphic units. samples were sieved to the 0.09–0.16 mm size fraction, followed by subsequent dissolution of calcite. the heavy mineral association (hma) was separated using bromoform (δ(chbr3) = 2.84 gcm–3). qualitative and quantitative composition of the hma was established after the determination of 300–400 grains applying the ribbon counting method (menge & maurer, 1992). results are presented in table 1 (accepted and modifi ed from kovačić & grizelj, 2006). 3.2. data processing multiple (multi-group) discriminant analysis (mda) is a powerful multivariate technique which is recently widely applied to many problems in geology, particularly in cases when a large amount of data is collected from different lithological or lithostratigraphical units, in an attempt to defi ne their boundaries. its principal purpose is to establish the major sources of difference between the a priori defi ned groups allowing the minimum misclassifi cation error rates for their members. generally, this is achieved in such a way that the variance between the original groups is maximized in relation to the variance within each particular group (dillon & goldstein, 1984). in the process, a hypothesis is tested that all observed groups have the same multivariate mean, against the alternative that at least one mean is different (rock, 1988). if the alternative hypothesis is not rejected (which does not mean that the separation of all groups is necessarily optimal), then discriminant scores can be computed from the original data set allocating each object (single sample) along one or more mutually independent (perpendicular) vectors – linear discriminant functions (e.g., krumbein & greybill, 1965; doornkamp & king, 1971; davis, 1986). in this way the multivariate problem is simply and parsimoniously cut down to the least dimensional solution depending on the number of groups (k–1), or variables (p) if the latter is greater (k<p). investigation is focused on separation between lithostratigraphic units using the data on the hma from the sampled siliciclastic material of the upper miocene and lower pliocene sands in the sw part of the pbs. five groups described above as oza, and, hzb, plu and cer (lithostratigraphic units cro and meb are not defi ned as specifi c groups) including more than a hundred samples in total were subject to investigation. descriptor variables are represented by 10 minerals of hma including chlorite (chl), dolomite (dol), tourmaline (tur), zircon (zrn), rutile (rt), amphibole (amph), garnet (grt), kyanite (ky), staurolite (st) and minerals from the group of epidote-zoisite-clinozoisite (epzoczo). regardless of the positive skewed frequency distributions of the analyzed variables, a bias usually ascribed to complex nonlinear responses within the natural system (siliciclastic material of the sands) represented by hma, the data were not subject to transformation. common transformation procedures were omitted following the idea that data processed by various multivariate methods should be left in their original form since transformed variables can develop their own patterns of behavior (size, 1987; mann, 1987; agrawal, 1995). a single variable exhibiting distribution close to normal was epzoczo. 4. results and discussion discriminant analysis of the investigated lithostratigraphic units represents a multiple-group discrimination involving fi ve groups (k=5). in this case discriminant model is built of four discriminant functions (k–1) completely explaining the differences between the respective groups. before that, the overall signifi cance of their discrimination is tested by appropriate multivariate tests (table 2a) disclosing the vanishingly low associated probability (p<0.000), a rationale requir ed to safely proceed with computing discriminant functions (dfs). with respect to the statistical signifi cance of the variation between the observed groups (p-level, table 2b) and kovačić et al.: discriminant function analysis of upper miocene and pliocene sands from the southwestern part of the pannonian basin system, croatia geologia croatica 193 table 1: composition of the hma of upper miocene and pliocene sands from the southwestern part of the pannonian basin system. chl – chlorite, dol – dolomite, op – opaque mineral, bi – biotite, thm – translucent heavy minerals, tur – tourmaline, zrn – zircon, rt – rutile, amph – amphibole, grt – garnet, ky – kyanite, st – staurolite, epzoczo – epidote-zoisite-clinozoisite, oth – other minerals, + – less than 1%. sample unit heavy minerals (%) translucent heavy minerals (%) chl dol op bi thm tur zrn rt amph grt ky st epzoczo oth bol 1/2 oza + 34 66 2 + 1 + 4 87 5 5/4 40 60 2 2 + 5 88 2 dbr-i 2/1 23 77 + + + 4 91 3 4/1 29 71 1 + 1 2 92 3 12/1 16 84 + 1 95 3 bor 1/1 23 77 + + 3 2 1 87 6 oza-i 3/2 2 92 6 11 48 38 + 2 + 6/1 1 93 6 14 53 27 2 2 + 1 sla 3/4 70 27 3 25 6 4 40 2 9 9 5 top-ii 3/1 2 92 + 6 18 27 35 1 12 3 4 6/4 17 56 10 7 13 43 28 1 10 3 2 kra-i 13/1 and 1 91 6 2 46 5 13 8 2 6 15 5 mal-i 5/2 1 70 11 18 10 3 7 24 2 15 31 8 7/1 17 41 11 31 8 1 4 1 28 3 14 34 7 krt-ii 16/1 1 61 8 30 4 + 7 + 49 3 11 20 5 8/1 5 34 13 48 6 4 25 5 21 34 5 11/1 5 11 18 66 5 3 41 2 19 26 4 16/1 3 12 85 4 3 4 42 4 12 27 4 pač-i 1/1 7 11 13 69 3 5 65 1 7 13 6 20/1 2 5 11 82 2 5 72 3 5 11 2 39/1 18 11 14 57 8 + 3 53 2 16 14 3 pož-i 1/2 1 5 8 86 6 1 5 5 62 1 7 11 2 6/1 21 10 13 56 4 + 3 4 36 1 13 34 4 mat-i 1/1 4 10 2 84 6 4 + 57 3 3 14 12 bob-i 10/1 41 27 9 23 6 2 28 7 12 37 8 25/1 35 31 7 27 5 2 2 28 5 18 35 5 pož-i 23/1 15 24 14 47 3 + 2 4 32 3 17 35 3 and-i 2/1 + 14 + 85 1 + 2 63 1 2 26 4 29/1 19 32 1 48 5 1 1 54 + 7 21 10 mat-i 8/1 + 10 89 4 3 74 1 4 8 6 14/1 1 11 88 5 2 71 2 4 10 6 mir-i 2/1 13 21 1 65 8 9 + 37 6 6 26 7 6/1 + 8 92 2 3 + 57 4 3 28 2 6/3 16 84 2 4 57 2 2 31 2 7/4 8 17 + 75 7 2 26 5 8 38 14 12/1 2 13 85 3 3 39 3 7 39 6 maj-i 1/2 29 31 7 33 4 + 1 2 36 2 12 40 2 3/1 15 16 12 57 6 1 3 33 3 17 34 3 tol –ii 8/1 21 39 4 36 5 5 16 20 4 16 27 7 bek-i 2/3 3 9 1 87 2 1 4 31 1 3 46 12 mma-i 5/1 8 92 5 2 3 7 2 12 57 12 11/1 1 6 93 2 2 3 26 1 10 44 12 bek-ii 3/1 21 8 15 56 2 5 1 17 + 3 59 11/1 39 12 49 5 1 13 12 1 5 51 12 sel-i 1/1 7 10 83 3 + 1 20 28 2 7 28 10 sem-i 12/1 3 18 + 78 5 2 4 22 4 10 39 14 22/1 1 12 1 86 4 1 3 15 2 9 51 15 bdl-i 5/1 2 15 83 2 3 9 41 2 6 32 5 6/3 1 11 88 2 2 7 40 2 4 32 11 mil-i 1/3 17 5 15 63 6 4 3 19 2 20 40 6 3/1 6 11 13 70 3 4 1 20 1 27 40 4 pop 1/1 2 2 7 89 1 1 4 3 35 7 19 25 5 5/4 7 10 6 77 3 1 1 23 3 33 33 3 nac-iii 6/1 21 79 3 + 4 2 3 21 57 9 geologia croatica 62/3geologia croatica 194 sample unit heavy minerals (%) translucent heavy minerals (%) chl dol op bi thm tur zrn rt amph grt ky st epzoczo oth tol-ii 14/1 hzb 24 37 6 33 3 2 8 28 3 19 29 5 sel-i 30/1 47 18 35 4 1 4 9 18 3 58 3 38/1 2 11 + 87 2 2 7 27 3 6 43 10 vv 1 + 14 85 4 1 6 2 19 3 13 41 11 plu-i 1/1 33 32 6 + 28 2 4 21 23 6 12 20 12 8/1 27 39 3 31 6 + 1 26 18 6 17 15 10 11/1 7 4 10 79 4 + 3 14 28 3 15 23 9 19/1 14 86 4 + 2 22 + 6 14 42 9 plu-iii 1/1 2 + 11 86 3 4 6 38 6 7 28 8 mal-i 12/2 9 11 18 62 2 2 6 40 4 12 26 8 pg-2 2 8 14 76 2 + 1 7 48 4 5 28 4 d-1 + 7 93 3 2 11 46 4 10 19 5 d-2 8 92 3 2 2 6 19 64 4 nac-iii 6/3 9 91 33 14 23 24 2 4 plu-ii 1/1 21 79 9 2 5 4 5 27 40 8 4/1 14 86 5 1 2 3 5 29 52 3 plu-iii 2/1 + 16 86 5 4 5 1 7 15 56 7 3/1 22 78 6 8 + 7 22 52 4 4/1 34 66 7 + 8 + + 13 28 39 3 pb 1 32 68 8 + 17 11 18 43 2 mal-i 14/2 29 71 9 + 7 5 24 47 7 plu-ii 6/2 plu 25 75 11 + 11 + 10 21 43 3 6/1 + 17 82 7 8 + 2 11 38 29 4 vbo-i 17/1 12 7 81 23 1 3 1 10 26 33 3 sel-i 45/1 24 76 2 1 6 3 32 5 5 38 8 dzg-i 3/1 47 53 33 14 23 24 2 4 10/1 48 52 25 1 18 26 23 3 4 20/2 + 46 54 18 + 12 + 25 27 10 7 21/2 + 63 36 20 2 18 21 30 4 5 plu-ii 7/2 39 61 13 2 14 1 17 33 17 3 vtv-i 1/1 53 47 12 3 26 22 32 2 3 6/1 51 49 15 23 24 35 + 2 9/1 55 45 29 2 13 + 29 24 2 17/1 48 52 18 1 15 26 37 + 2 mal k/1 49 51 33 2 12 22 27 2 2 k/2 51 49 29 1 15 21 29 3 2 nac-iii 12/2 cer 11 89 25 1 18 26 23 3 4 nac-iv 1/1 17 83 18 + 12 + 25 27 10 7 5/1 29 71 20 2 18 21 30 4 5 7/1 20 80 13 2 14 1 17 33 17 3 vrb 7/1 2 29 69 12 3 26 22 32 2 3 13/1 2 32 21 45 15 23 24 35 + 2 17/1 6 26 68 29 2 13 + 29 24 2 22/1 9 21 70 18 1 15 26 37 + 2 27/1 1 13 14 72 33 2 12 22 27 2 2 39/1 1 25 74 29 1 15 21 29 3 2 table 1: continued. kovačić et al.: discriminant function analysis of upper miocene and pliocene sands from the southwestern part of the pannonian basin system, croatia geologia croatica 195 fi gu re 4 : s ca tt er pl ot o f v ar ia bl e lo ad in gs (a ,d ), gr ou p m ea ns (b ,e ) a nd d is cr im in an t s co re s ( c, f) in re du ce d di sc rim in an t s pa ce (d f1 /d f2 a nd d f1 /d f3 ). a b c d e f geologia croatica 62/3geologia croatica 196 accom panying eigenvalues, only the fi rst three dfs which explain almost all the variability of the system (98.9%) were selected to defi ne dimensionality of the discriminant space. 4.1. building a model to construct a functional model around the computed dfs is vital to mda since it opens the door to the hidden relationship between groups not detected by direct observations and measurements. in this way the natural processes can be inferred underlying the mathematical structure of analyzed data. individual assessment of each descriptor (hma) is needed for this purpose, and discriminant loadings (structure coeffi cients), which represent simple correlations of variables with respective dfs, are used here to assist the overall discrimination between the groups. inspection in a model is particularly helpful via the variable diagrams which provide the easiest and most informative insight into the structure of discriminant space, both indicating which descriptors should be kept in the geological interpretation of discriminant functions and which descriptors most clearly separate the a priori defi ned groups. in this respect, a number of variables with minor contributions to discrimination are excluded from the interpretation of the model. among these are dol, chl and epzoczo which crowd together around the main centroid owing to their small discriminant loadings (fig. 4a, d). furthermore, the relationship between variables and related groups can be likewise displayed geometrically, viewing dfs as mutually perpendicular vectors (axes) in the reduced discriminant space. however, the variable and group diagrams cannot be contrasted directly since different scales are employed in each case. the scatterplot of variable loadings (fig. 4a, d) is drawn with the axes shown as normalized vectors, while scatterplots of group means (fig. 4b, e) and discriminant scores (fig. 4c, f) are constructed using discriminant score vectors. as a result, interdependence between variables and related groups can be elucidated regarding their shared position along the respective discriminant axis. in both diagrams, contribution to the overall discrimination of points placed close to the axes intersection is negligible. typically, a reciprocal relationship between the group means (centroids) and variables along the respective discriminant axis will determine the geological nature of the computed mathematical model. nevertheless, however revealing these diagrams may be about the real geological processes generating the character of mutual group relationships, the best way to evaluate how much the groups really differ is to take a closer look into the distance matrix, (matrix of squared mahalanobis distances; table 3). based on these values, the plu unit falls farthest away from all other units, namely the oza (69.38), and (43.46), hzb (31.33) and cer (27.82). however, there is some overlap between the cer, hzb and and units. the closest together are cer and hzb (2.96), then cer and and (4.13), and fi nally and and hzb (5.98). judging from the calculated mahalanobis distances, the oza unit is not very different from the cer (15.91), and (16.61) and hzb (17.45) units, lying somewhere in the middle of the fi rst two cases. the rationale for similarities or disparities between the investigated groups (lithostratigraphic units) can be found in specifi c geologic processes which control the spatial distribution of the descriptor variables (hma) during evolution of the tectonic and sedimentological history of the study area. 4.2. labeling the discriminant functions labeling discriminant functions is a starting point in interpreting the mathematically computed (structural) model in terms of processes. in this manner, the structural model is transformed into a process with each df contributing to a single independent (geologic) process in the overall separation of the groups. variables participate in this structure-process conversion as the building blocks assuming the role of process descriptors. in the computed mathematical model, the fi rst discriminant function df1 makes the greatest contribution to discrimination between the groups, accounting for more than 73% of the total variability. it is essentially monopolar, being marked by the high positive loadings of dominant translucent heavy minerals, kyanite (ky) and, to a lesser degree, staurolite (st), while the major part of the hma suite is concentrated around the main centroid (fig. 4a, d). if compared to the scatterplot of group means, it illustrates the separation of the plu unit from the other four groups (particularly oza) based on enrichment/depletion of kyanite in their modal composition. while the plu unit is characteristic for its higher content of kyanite, other lithostratigraphic units in the sw part of pbs are rather indifferent to it (with the exception of the oza unit showing a slightly decreased content of ky). in accordance with the relative prominence of this mineral, df1 table 2: tests of signifi cance. a) multivariate test of the overall signifi cance of discrimination. b) tests of residual roots (discriminant functions). a) number of variables in the model 10 wilks’ λ 0.038 approximate f ratio 11.387 degrees of freedom 40; 331 p-level p<0.000 b) df eigenvalue eigen (%) canon. r wilks’ λ chi-sqr. df p-level 1 5.533 73.06 0.920 0.038 303.1 40 0.000 2 1.390 18.35 0.763 0.247 129.5 27 0.000 3 0.568 7.50 0.602 0.589 48.9 16 0.000 4* 0.082 1.08 0.275 0.924 7.3 7 0.402 note: df marked* is statistically insignifi cant table 3: squared mahalanobis distances. oza and hzb plu cer oza 0.00 16.62 17.45 69.38 15.91 and 16.62 0.00 5.98 43.46 4.13 hzb 17.45 5.98 0.00 31.33 2.96 plu 69.38 43.46 31.33 0.00 27.82 cer 15.91 4.13 2.96 27.82 0.00 kovačić et al.: discriminant function analysis of upper miocene and pliocene sands from the southwestern part of the pannonian basin system, croatia geologia croatica 197 can be readily identifi ed as the kyanite function. geologically, the signifi cant abundance of ky and st in the detritus of the plu unit sands serves as a good indicator of the weathering of rocks of medium grade regional metamorphism in the source area. due to the marked dominance of df1 in the discriminant model it unmistakably highlights the central geologic process in the development of the upper miocene and pliocene sands in the sw part of the pbs – a process controlling the distribution of ky as the ‘key’ mineral from the incipient stage of parent rock weathering through transport to sedimentation and possible re-deposition of sedimentary material in the later stages of the development of the sedimentary basin or its particular portions. the second discriminant function df2 accounts for only 18% of the total variance between the groups. in contrast to df1 it is characteristically bipolar and can be interpreted as refl ecting the inverse relationship between garnet on the one side and zircon with (to a less extent) rutile on the other, after which it can be properly labeled the garnet-zircon function. from visual inspection of the related variable and group scatterplots (fig. 4a, b), it is evident that after acknowledging this variable pattern, df2 further separates the oza unit from the remaining groups. this partition is based principally on the reduced content of garnet and seconded by the higher content of zircon and rutile in the oza unit sand composition. the content of garnet is slightly higher with part of the samples in the and unit (fig. 4c) while the remaining three groups (cer, hzb and plu units) remain indifferent in this relationship sticking to the middle position with the least mean values. this situation highlights their average hma composition with respect to the df2 labeling minerals. in a geological (sedimentological) sense, df2 must be observed through the bond of the two minerals, zrn and rt, which are amongst the ultra stable detrital minerals in the sedimentary systems, against grt which is considered to be the indicator of high energy conditions during transport (rothwell, 1989). being a garnet-zircon function, df2 in a functional sense (in a sedimentary system) can either refl ect variations in the parent rock mineral composition via its mineral content in the detrital material. in other words, zrn and rt can be found in the composition of older sedimentary rocks (most probably derived from more acid igneous rocks), or signal the prevailing hydraulic conditions closely associated with sedimentary environment. this amounts to saying that heavy minerals (having great density) are concentrated under high energy conditions (grt) while others, such as zrn and rt prefer environments of low stream power. it could be noted in passing that a similar pattern of sedimentary process regime was already deduced in a quite different environment where the quaternary sediments were divided into several genetic groups (peh et al., 1998). although results can be inconclusive in this respect due to the still limited volume of similar investigations needed for reliable cross-comparison, it is interesting to observe that source rocks seem to play the dominant role in distribution of hma in the basin systems, at least at a regional scale, while the hydraulic conditions controlling their physical and chemical stability during transport and deposition are secondary. the third discriminant function df3 (explaining barely 7.5% of the system variance) is also bipolar but dominantly loaded with only one variable – amphibole (amph) – by which the hzb unit is weakly separated from the others (fig. 4d, e). amphibole is negatively associated with the set of variables weakly loaded on the positive pole of df3 among which some minerals, very resistant to weathering, such as rt, zrn and tur, are highlighted. since amphibole is a highly unstable mineral component this discriminant function can be interpreted as the amphibole function representing, in sedimentological sense, a function of the chemical stability of hma in the investigated arenaceous (sandy) deposits. obviously, the hzb unit must have been deposited under conditions of prolonged stability or amphibole would not otherwise be signifi cantly present to serve as the key mineral in its discrimination. similarly, with respect to environmental quiescence and stability, it could be said that all other groups are more or less well separated from hzb towards the zrn(rt) quarter of the diagram, indicating the more turbulent conditions of their deposition. 4.3. classifi cation results classifi cation effi ciency is often proved to be of greater use geologically in the process of discrimination than various statistical tests (rock, 1988). it is particularly evident in cases when mda is applied to a large volume of data scattered across various spatial boundaries such as geological (lithostratigraphical) units, depth intervals, or profi le lines, being composed of the same suite of observed or measured attributes (e.g. physical or chemical properties) (e.g. saftić et al., 2001; peh et al., 2008; kovačić, 2004; grizelj, 2008). it is also evident in applying statistical analysis in order to test fro group differences based on lithostratigraphical units properties (e.g. malvić et al., 2005). in this context, classifi cation rates in original or a priori defi ned lithostratigraphic units can be readily inspected by contrasting the mathematically ‘predicted’ (computed) and original (‘natural’) group membership of individual samples (table 4). from table 4 it is apparent that the discriminant model is organized with relatively high effi ciency which exceeds 80%. however, for certain groups, namely cer and hzb, overlap is considerable which is evident from the low mahalanobis distances (table 3), and can be visually scanned from respective sample diagrams (fig. 4c, d). for instance, table 4: classifi cation matrix. observed group memberships predicted group memberships oza and hzb plu cer % correct oza 10 1 0 0 0 90.91 and 1 40 3 0 1 88.89 hzb 0 5 14 0 3 63.64 plu 0 0 2 12 0 85.71 cer 0 4 0 0 5 55.56 total 11 50 19 12 9 80.20 geologia croatica 62/3geologia croatica 198 only fi ve samples out of nine of the cer unit are assigned to that particular group while the rest are more similar to the and unit, which has a classifi cation rate barely in excess of 55%. in the case of the hzb unit, the success rate is somewhat greater and amounts to over 63%. here, eight samples out of 22 are closer to other groups, including the and (5) and cer (3) units. this information indicates the signifi cant inhomogeneity of the cer unit where more than 44% of allocations are unequivocally misclassifi ed (and unit), while at the same time, an equal number of samples are a posteriori allocated to the former at the expense of other litostratigraphic units: hzb (3) and and (1). the oza, plu and and lithostratigraphic units are distinguished by relatively high classifi cation effi ciency. among these, oza unit is recognized for its homogeneity (table 4). its modal composition is so unique that one can hardly fi nd similar sand grade sedimentary material accounting for the fact that only a single sample of this unit is incorrectly classifi ed changing its group affi liation for and, and vice versa. one of the samples originally ascribed to and was later classifi ed as a member of the oza unit (table 4). such an almost optimal separation can be explained by a different source for the clastic material in its detrital composition relative to other units. namely, the clastic detritus of the oza unit is of local provenance (after kovačić & grizelj, 2006), and is derived from the weathering of older sedimentary rocks while the material forming the other units must have been transported from more distant areas, originating form the weathering of a diverse suite of metamorphic, sedimentary and igneous rocks. a cross-exchange of two single group assignments between the oza and and units can be interpreted in the knowledge that both samples were collected in the žumbe rak mt. where clastic detritus from both sources combines. a high classifi cation rate is also characteristic for the plu unit (table 4). this is expected in as much as, (after kovačić & grizelj, 2006), a signifi cant proportion of its detritus is derived from the alumina-rich metamorphic rocks as opposed to other units. misclassifi cation of two plu samples into the hzb unit can be easily explained by the fact that the former conformably overlies the latter while their boundary is not clearly defi ned. also, according to kovačić & grizelj (2006), the same petrologic province responsible for supplying sediment for the and, hzb and cer units, produces great similarity of their clastic material which is the main reason why a considerable number of samples show reciprocally incorrect affi liations. however, almost 90% of the and samples are a priori correctly classifi ed, strongly confi rming its homogeneous composition (table 4). in this connection, with the and unit being the ‘heaviest’, some samples were assimilated from the other two units, a typical effect where one group, being larger than the other, draws the members of a smaller group closer to its own centroid. as a result, the post hoc assignments of smaller groups inevitably undergo low classifi cation rates (slightly over 50%) but a larger group better conveys the mean modal composition. 5. conclusion multiple discriminant analysis applied to the lower miocene and pliocene sands from the sw part of the pannonian basin system showed that specifi c mineral associations characteristically relate to particular lithostratigraphic units outcropping in the area. these relationships allow some defi nite conclusions to be drawn about specifi c stages of the sedimentary cycle, and conditions prevailing during weathering, transport and deposition of the studied sedimentary material. important results of mda can be summarized as follows: (1) three discriminant functions account for almost all variance between the groups (99%) and can be easily interpreted in geological terms as: a) df1 – kyanite (ky) func tion indicating source rock mineralogy (alumi narich, metamorphic rocks); b) df2 – garnet-zircon/rutile (grt-zrn/rt) function explaining the relationship betwe en source rock mineralogy (older clastic sediments and felsic igneous rocks – zrn/rt) and hydraulic conditions controlling transport and deposition of detritus (grt) and; c) df3 – amphibolite function accounting for the processes of chemical and physical stability in the sedimentary cycle. (2) the kyanite function is by far the most important part of the discriminant model accounting for almost 3/4 of all the processes in the investigated area, placing great importance on the area of alumina-rich metamorphic rocks as the main provenance of the clastic material. (3) oza, plu and and units are set apart by the highest classifi cation effi ciency. the most discrete (most different) among these is the plu unit (by df1). however, the ozalj unit is recognized for its homogeneity (the greatest classifi cation rate). the andraševec unit is the most massive, prone to scavenging the members of smaller groups. at the other end of the scale, the cer and hzb units represent the mean composition of hma with respect of all the investigated groups. finally, it must be stated that interpretation of changing affi liations assessed by discriminant analysis can greatly improve geological mapping results because otherwise very similar sand units, previously differentiated into predefi ned lithostratigraphic and chronostratigraphic compartments during fi eld work, can now be reconsidered. inhomogeneity of the hma within particular units can be used as an indicator tool for visualizing the dynamics of a sedimentary system and of its development, particularly concerning the processes of palaeotransport, sedimentation and subsequent re-deposition. some widespread lithostratigraphic such as the andraševec (hrvatsko zagorje, žumberak mt. and slavonian mts.) may indicate specifi c variations in lithology, texture, facies, sedimentary environments, sedimentary control on depositional sequences, and even age. in order to specify which geologic process had the dominant role in the sedimentary cycle resulting in the fi nal differentiation of lithostratigraphic units, it is very important in discriminant analysis to associkovačić et al.: discriminant function analysis of upper miocene and pliocene sands from the southwestern part of the pannonian basin system, croatia geologia croatica 199 ate individual groups with respective variable descriptors (hma). thus, one can single out the process which is involved, and with what priority, in the sedimentary regime. as previously mentioned, the most valid implication emerging from the discriminant model is the complete dominance of df1 since it explains the greatest proportion of the total variability. for this reason it unequivocally (in the process sense) highlights the most important issues in the genesis of the upper miocene sand deposits in the ws portion of pbs; the provenance of the detritus indicating the alumina-rich metamorphic source rocks, typical for the plu unit. acknowledgments this study was funded by the ministry of science, education and sports, republic of croatia, projects ‘evolutionary changes of the dinarides from subduction to modern adriatic beaches’ (119-11911551159), the map of mineral resources of the republic of croatia (1811811096-1104) and basic geological map of the republic of croatia, 1:50000 (181-1811096-1093). 6. references agrawal, s. (1995): discrimination between late-orogenic, post-orogenic, and anorogenic granites by major element compositions.− j. geol., 103, 529−537. basch, o. (1983): osnovna geološka karta sfrj 1:100000. tumač za list ivanić grad. [basic geological map of sfry 1:100000. geology of the ivanić grad sheet − in croatian, english summary].− institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd, 1−66. davis, j.c. (1986): statistics and data analysis in geology.− john wiley and sons, new york, 646 p. dillon, w.r. & goldstein, j. (1984): multivariate analysis: methods and applications.− john wiley & sons, new york, 575 p. doornkamp, j.c. & king, c.a.m (1971): numerical analysis in geomorphology: an introduction.− edward arnold ltd., london, 372 p. grizelj, a., tibljaš, d. & kovačić, m. (2007): mineralogical and geochemical characteristics of upper miocene pelitic sediments of zagorje basin, a pannonian sub-basin, croatia.− geol. carpat., 58, 263−276. grizelj, a. (2008): mineraloške i geokemijske značajke miocenskih pelitnih sedimenata jugozapadnog dijela panonskog bazena [mineralogical and geochemical characteristic of miocene pelitic sediments from south-western part of panonnian basin − in croatian with an english summary].− unpubl. phd. thesis, faculty of science, university of zagreb, 192 p. horváth, f. (1995): phases of compression during the evolution of the pannonian basin and its bearing on hydrocarbon exploration.− mar. petrol. geol., 12, 147–154. horvath, f. & royden, l.h. (1981): mechanism for the formation of the intra-carpathian basins: a rewiev.– earth sci. rew., 3–4, 307−316. jamičić, d. (1995): the role of sinistral strike-slip faults in the formation of the structural fabric of the slavonian mts. (eastern croatia).− geol. croat., 48, 155–160. kováč, m., nagymarosy, a., oszczypko, n., csontos, l., slaczka, a., marunteanu, m., matenco, l. & marton, e. (1998): palinspatic reconstruction of the carpathian–pannonian region during the miocene.− in: rakús, m. (ed.): geo dynamic de vel opment of the western carpathians. miner. slov. – monograph., bratislava, 189–217. kovačić, m. (2004): sedimentologija gornjomiocenskih naslaga jugozapadnog dijela panonskog bazena [sedimentology of the upper miocene deposits from the southwestern part of pannonian basin − in croatian with an english summary].− unpubl. phd. thesis, faculty of science, university of zagreb, 203 p. kovačić, m., zupanič, j., babić, lj., vrsaljko, d., miknić, m., bakrač, k. hećimović, i., avanić, r. & brkić, m. (2004): lacustrine basin to delta evolution in the zagorje basin, a pannonian sub-basin (late miocene: pontian, nw croatia).− facies, 50, 19−33. kovačić, m., avanić, r., bakrač, k., hećimović, i., filjak, r. & morić, a. (2005): gornjomiocenski sedimenti dilj gore [late miocene sediments of dilj mt. – in croatian].− knjiga sažetaka, 3. hrvatski geološki kongres, opatija, 77−78. kovačić, m & grizelj, a. (2006): provenance of the upper miocene clastic material in the southwestern part of the pannonian basin.− geol. carpat., 57, 495−510. krumbein, w.c. & greybill, f. a. (1965): an introduction to statistical models in geology.− mcgraw-hill, toronto-london-sidney, 475 p. magyar, i., geary, d.h. & müller, p. (1999): paleogeographic evolution of the late miocene lake pannon in central europe.− palaeogeogr. palaeoclimatol. palaeol., 147, 151−167. malvić, t., velić, j & peh, z. (2005): qualitative-quantitative analyses of the infl uence of depth and lithological composition on lower pontian sandstone porosity in the central part of the bjelovar sag (croatia).– geol. croat., 58/1, 73–85. mann, c.j. (1987): misuse of linear regression in earth sciences. in: size, w.b. (ed.): use and abuse of statistical methods in earth scienes.− oxford university press, new york, 74–106. marton, e., pavelić, d., tomljenović, b., avanić, r., pamić, j. & marton, p. (2002): in the wake of a counterclockwise rotating adriatic microplate: neogene paleomagnetic results from northern croatia.− int. j. earth. sci., 91, 514−523, doi: 10.1007/s00531-001-0249-4 menge, m.a. & maurer, h.f.w. (1992): heavy minerals in colour.− chapman & hall, london, 151 p. pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.– bas. res., 13, 359–376. peh, z., novosel-škorić, s. & kruk, lj. (1998): discriminant analysis as a tool for the distinction of quaternary sediments in the region of đurđevac.− geol. croat., 51/1, 47–58. peh, z., šajn, r., halamić, j. & galović, l. (2008): multiple discriminant analysis of the drava river alluvial plain sediments.– environ. geol., 55, 1519–1535, doi: 10.1007/s00254-007-1102-2. rock, n.m.s. (1988): lecture notes in earth sciences, 18: numerical geology.− springer-verlag, berlin-heidelberg-new york-london-paris-tokyo, 427 p. rögl, f. (1998) paleogeographic considerations for mediterranean and paratethys seaways (oligocene to miocene).− ann. naturhist. mus. wien, 99a, 279–310. rögl, f. (1999): mediterranean and paratethys. facts and hypotheses of an oligocene to miocene paleogeography (short overview).− geol. carpat., 50/4, 339−349. rögl, f. & steininger, f.f. (1983): vom zerfall der tethys zu mediterran und paratethys.− ann. naturhist. mus. wien, 85a, 135–163. rothwell, r.g. (1989): minerals and mineraloids in marine sediments: an optical identifi cation guide.− elsevier, london, 279 p. royden, l.h. (1988): late cenozoic tectonics of the pannonian basin system. in: horváth f. & royden l.h. (eds.): the pannonian basin. a study in basin evolution.− am. assoc. petrol. geol. mem., 45, 27–48. geologia croatica 62/3geologia croatica 200 royden, l.h., horvath, f., nagymarosy, a. & stegena, l. (1983): evolution of the pannonian basin system: 2. subsidence and thermal history.– tectonics, 2, 91–137. saftić, b., peh, z., velić, j. & jüttner, i. (2001): interdependence of petrophysical properties and depth: some implications of multivariate solution between the lower pontian hydrocarbon-bearing sandstone units in the western part of the sava depression.– geol. croat. 54/2, 259–277. size, w.b. (1987): use of representative samples and sampling plans in describing geologic variability abd trends. in: size, w.b. (ed.): use and abuse of statistical methods in earth scienes.− oxford university press, new york, 3−20. šćavnićar, b. (1979): pješčenjaci pliocena i miocena savske potoline [sandstones of the miocene and pliocene age in the sava depression − in croatian, with an english abstract].− scientifi c commitee for petroleum of the yugoslavian academy of science and art (jazu), 3rd scientifi c congress of section for applied geology, geophysics and geochemistry, novi sad (1977), zagreb, 2, 351–383. šikić, k., basch, o. & šimunić, an. (1979): osnovna geološka karta sfrj 1:100000, tumač za list zagreb [basic geological map of sfry 1:100000, geology of the zagreb sheet – in croatian, with an english summary].– geološki zavod zagreb, savezni geološki zavod, beograd, 1–81. šimon, j. (1973): o nekim rezultatima regionalne korelacije litostratigrafskih jedinica u jugozapadnom području panonskog bazena.– nafta, 24/12, 623–630. šimon, j. (1980): prilog stratigrafi ji u taložnom sustavu pješčanih rezervoara sava-grupe naslaga mlađeg tercijara u panonskom bazenu sjeverne hrvatske.− unpubl. phd. thesis, faculty of science, university of zagreb, 66 p. šimunić, an. & šimunić, al. (1987): rekonstrukcija neotektonskih zbivanja u sjeverozapadnoj hrvatskoj na temelju analize pontskih sedimenata [the reconstruction of neotectonic occurrence in north western croatia based on analyses of pontian sediments – in cro atian, with an english abstract].– jazu (zagreb), 431/22, 155–177. tomljenović, b. & csontos, l. (2001): neogene–quaternary structures in the border zone between alps, dinarides and pannonian basin (hrvatsko zagorje and karlovac basins, croatia).– int. j. earth. sci., 90, 560–578, doi: 10.1007/s005310000176 velić, j. (1980): geološka građa zapadnog dijela savske potoline.− unpubl. phd. thesis, faculty of science, university of zagreb, 139 p. vrsaljko, d. (2003): biostratigrafi ja miocenskih naslaga žumberačkog i samoborskog gorja na temelju mekušaca [biostratigraphy of miocene deposits from žumberačko and samoborsko gorje mts. on the basis of molluscs − in croatian, with an english summary].− unpubl. phd. thesis, faculty of science, university of zagreb, 147 p. manuscript received march 18, 2009 revised manuscript accepted june 30, 2009 available online october 02, 2009 available online ??????????? 1. introduction as a convenient medium for geochemical mapping the stream sediment represents a silty fraction (clay to finegrained sand) transported and deposited in a recent stream channel. this sampling medium is still mostly preferred, particularly in areas with temperate climate and a dense drainage network because its geochemical composition is regarded as the most informative for regional reference purposes, not only in the domain of mineral exploration, but also in the area of pollution assessment (darnley et al., 1995). it is well known that the petrographic, mineralogical and geochemical a factor model of the relationship between stream sediment geochemistry and adjacent drainage basin lithology, medvednica mt., croatia josip halami∆ 1, zoran peh1, dragan bukovec 2, slobodan miko1 and lidija galovi∆ 1 composition of such a composite sample, if taken in an uninhabited area, roughly reflects the bedrock lithology upstream from the sampling site, anthropogenic influences being low or absent. due to the specific geologic fabric, with a prevalence of various types of non-carbonate rocks, a well dissected landscape with dense drainage network has been developed into a distinguishing feature of the medvednica mt. its numerous valleys offer plenty of stream material for reconnaissance geochemical surveys and various regional studies. however, the abundant lithological diversity may prove to be a disadvantageous feature as it results in progressive mixing of the eroded and transported bedload material due to the subsidiary stream channels downstream. as a consequence, the geochemical composition is charged with “noise” which renders interpreting the provenance of source material considerably difficult. some authors (e.g. ottesen et al., 1989) also draw atttention to the opposite effect in the case of long and narrow valleys without tributaries, when stream sediment samples taken at intervals along the valley are no more than replicas of the same material from the same source, with no new geochemical information. the study area abounds with both examples. in order to reconcile these extremes and elucidate the relationships between geochemical composition of the stream sediment samples and bedrock lithology underlying the sampled drainage basins we offered an approach based on multivariate statistics: the factor analysis with a series of factor score maps of the investigated area. this type of numerical analysis, applied to a great number of surveyed medvednica streams (247), should also offer an additional insight into the possible technogenic and anthropogenic impacts that might be present in the stream sediment geochemistry, particularly on the southern slopes of medvednica mt. and its inhabited footfall areas. 2. geological setting the medvednica mt. is a prominent topographic unit in northwestern croatia occupying an area of about 300 k m2 (fig. 1). its main body is formed of three parts: geologia croatica 54/1 37 51 10 figs. 2 tabs. zagreb 2001 key words: stream sediment, lithology, drainage basins, geochemical composition, factor analysis, medvednica mt., croatia. 1 institute of geology, sachsova 2, hr-10000 zagreb, croatia. e-mail: igi-zagreb@zg.hinet.hr 2 croatian natural history museum, demetrova 1, hr-10000 zagreb, croatia. e-mail: bukovec@hpm.hr abstract a mathematical model is constructed to relate the geochemical composition of recent stream material in a number of catchments on medvednica mt. to a broadely defined bedrock lithology which repre sents the parent material for the former. it is a system based factor model, which synthesizes eight lithological and 25 geochemical variables (major, minor and trace elements), reducing their relationships to six geologically meaningful factors. five of these divulged a definite relationship between geochemistry and lithology. these are labelled as follows: factor of metamorphic rocks; factor of igneous rocks; factor of tertiary carbonate rocks; factor of parametamorphic rocks and factor of mesozoic carbonate rocks. two lithologies; the mesozoic clastic rocks and quaternary sediments showed no clear association to any of the factors. alternatively, one of the factors (f2) can be identified as “non-lithologic” indicating other, perhaps anthropogenic, contributions to the stream sediment geochemical composition. 38 geologia croatica 54/1 zagrebaëka gora, zelinska gora, and the area of hum©agudovec forest. their cores are predominantly built from the palaeozoic and mesozoic rocks of various origin and surrounded by younger, tertiary and quaternary sedimentary rocks (©iki∆ et al., 1978, 1979; basch, 1983a, b; ©imuni∆ et al., 1981, 1983) (fig. 3). palaeozoic rocks are represented by orthometamorphites and parametamorphites of silurian-devonian age, and weakly metamorphosed rocks of supposed lower permian age. according to recent investigations, some protoliths comprising a portion of this metamorphic complex are assigned to the triassic period (–ur–anovi∆, 1973; belak et al., 1995). the mesozoic of medvednica consists of the lower triassic clastic rocks, middle to upper triassic carbonates, as well as carbonates of triassic-jurassic and jurassic-cretaceous age. the cretaceous sedimentary rocks are predominantly represented by fine-grained clastics, while the carbonates of the “scaglia” facies appear more rarely. the cenozoic rocks are represented by tertiary (portions of palaeogene and neogene) sedimentary rocks and quaternary sediments. the former predominantly consist of fine-grained clastic rocks and marls, except for the badenian and pannonian rocks which can be categorized as limestones (mostly calcarenites). the lithological column for the quaternary is characterized by recent silts, sands and gravels deposited in the stream valleys, as well as sediments in the sinkholes within the area of ponikve. a number of various ore occurrences are disseminated over the entire area of medvednica mt., particularly in its central parts. in the belt of predominantly orthometamorphic rocks (green orthoschists), several occurrences of magnetite-haematite are recorded. there are also sections with great bodies of barite. the leadzinc ore occurences which contain admixtures of silver and copper are associated with partly recrystallized limestones and dolomites (marble) in the parametamorphic complex (©inkovec et al., 1988). 2.1. lithologic units due to geotectonic evolution of the terraine of northwestern croatia, the medvednica mt. portrays a complex geological structure, obvious from a variety of lithologic units formed over a large span of time (siluro-devonian to quaternary) concentrated in a relatively small area. therefore isolating the different rock masses into compact and definite lithologic units is an arduous endeavour. the composition of eight more or less closed lithologic units allowed all types of rocks to be represented within the smallest possible number of classes, while providing the maximum information. we restricted the criteria for classification of rocks into different groups to two items: 1) their origin (igneous, sedimentary and metamorphites); and 2) their age. here, we further subdivided sedimentary rocks into two classes (clastic and carbonate) disregarding the mechanism and environment of sedimentary processes as these would considerably increase the number of created groups and further aggravate the interpretation of results in this phase of the investigation. a problem also occured with the correct separation of various rocks into “pure” groups (e.g. parametamorphites from orthometamorphites, calcareous clastic rocks from carbonates, etc.) so that each lithologic unit is pre-labelled “predominantly”. according to the above considerations we synthesized eight lithological units on the medvednica mt. these comprise: 1) parametamorphic rocks, 2) orthofig. 1 location map of the medvednica mt. showing delineation of the investigated area. metamorphic rocks 3) igneous rocks, 4) mesozoic clastic rocks, 5) tertiary clastic rocks, 6) mesozoic carbonate rocks, 7) tertiary carbonate rocks, 8) quaternary sediments. metamorphic rocks of siluro-devonian and lower permian ages are classified into the group of parametamorphites while the greenschists, amphibole schists, metagabbros and metadiabases of the same age are assigned to the orthometamorphite group. the lithologic unit of igneous rocks is represented by quartzdiorites, diorites and quartzkeratophyres of upper palaeozoic age, as well as gabbros, basalts, diabases, and spilites of mesozoic age. the group of mesozoic clastic rocks includes the lower triassic as well as lower and upper cretaceous sedimentary rocks of different structure and texture (predominantly sandstones and siltites regardless of their composition, together with shales and, more rarely, marls). various rocks of palaeocene, ottnangian, karpatian, upper pontian, and plio-quaternary ages belong to the group of tertiary clastic rocks. some classification problems occurred with marls which comprise a considerable portion among other members. this refers to the lack of relevant references about the origin of the carbonate component in these rocks which may be clastic or chemogenic. part is determined as sandy-silty-clayey marl or as clayey-sandy marl (©iki∆ et al., 1979; basch, 1983b; ©iki∆, 1995) which was the main reason for classifying all these sedimentary rocks as clastic. dolomites and dolomitized limestones of triassic age, together with limestones and calcareous breccias are appointed to the group of tertiary carbonate rocks. badenian bioclastic limestones and algal (lithothamnium) limestones, together with clayey limestones of sarmatian and pannonian age form the group of mesozoic carbonate rocks. gravel, sand, silt and clay represent the quaternary sediments which occupy considerably small portions of the investigated area (fig. 3). 3. sampling and analytical methodology 3.1. sample material the main objective of analyzing the stream sediments of medvednica mt. was to obtain the baseline concentration values for a set of chemical elements that would be useful as a database in regional comparisons. the samples were collected according to a previously defined irregular network, with a sampling density of approximately 1 sample/km2 (detailed survey data). in order to reduce the anthropogenic and technogenic influence on the chemical composition of stream sediment samples as much as possible, the sampling network was designed such that sample sites avoided inhabited areas. samples were collected about 10 m upstream from the mouth of each stream in order to escape the zone of confluence, which would cause the mixing of bedload material during the season of high waters. on the sampling site, at least five grab samples of active fine grained sediment were collected from different places along a 30 m upstream section. from this material a composite sample was made weighing up to 1,5 kg. this procedure decreased the possible bias caused by local variability. in order to assure the same sedimentary conditions, sampling was carried out during the dry season. as many as 247 samples were collected (fig. 2), over an area of about 250 km2. 3.2. analytical procedure the air-dried samples were sieved to the <0,125 mm fraction, quartered and homogenized in a porcelain mortar resulting in a 10 g subsample. the stream sediment survey performed for implementation of the austrian geochemical atlas highlighted the fraction of <0,18 mm as giving the best results for most elements (thalmann et al., 1989). the samples were analyzed by indictively-coupled plasma spectrometry (icp-aes) after total hot 4 acid ( h cl -h n o3-hf-h c l o4) digestion at a temperature of 200° c in the acme analytical laboratories in vancouver. digestion of refractory minerals (casiterite, wolframite, chromite, spinel, beryl, zyrcon, tourmaline, magnetite and barite) is incomplete by this admixture. moreover, there is possible loss of as, sb, cr and au by volatilization of hclo4. si is totally volatilized by hf. 3.3. accuracy and precision samples were analyzed for 35 elements. in more than 50% of cases the measured values for several elements such as molybdenum, silver, uranium, gold, cadmium, antimony, bismuth, wolfram, berylium and tin fell below the detection limit which is why these are ommited from consideration. a total of 25 elements were accepted for further analysis. the analytical accuracy was checked using the international geological standards: gxr-5 and sjs-1 (recommended values by govindaraju, 1989; abbey, 1983; gladney & burns, 1984). for most determined elements, except aluminium and zirconium, the accuracy proved acceptable in the first approximation. precision was monitored by blind determination of 32 samples in a series of 20 pieces and statistically expressed as the variation coefficient (%). the laboratory errors were 37% for arsenic, 17% for lead and 11% for niobium. for the rest, the coefficient values are below 10% which is considered satisfactory. 39halamiê, peh, bukovec, miko & galoviê: a factor model of the relationship between... 40 geologia croatica 54/1 fig. 2 sample localities, streams, and drainage basins in the investigated area. fig. 3 generalized lithological map as derived from ©iki∆ et al., 1978; basch, 1983a; ©imuni∆ et al., 1981 schematised and simplified. 41halamiê, peh, bukovec, miko & galoviê: a factor model of the relationship between... 4. statistical treatment 4.1. a database in this study 247 samples were collected from the streams of the medvednica mt. for each sample, 33 descriptors consisting of eight lithological and 25 geochemical variables were observed and included in the factor analysis. inasmuch as the analysis of reconnaissance geochemical-geological data substantially makes use of a reach-scale pattern of variability, it was only natural to relate the sampled stream segments with the surrounding catchment area. this approach enabled lithological quantification within each drainage basin and the subsequent utilisation of this data to account for geochemical variation in the study area. the drainage basins were delineated in such a way that each basin segment corresponded to the area upstream and upslope of each sampling site, terminating at the location of the next sample site and at the top of the watersheds. therefore, many of the basins were nested, with successive samples being taken down the same stream. however, the absence of a hierarchical ordering prevented a close inspection into the controls over downstream dilution of possible anomalies, because mixing of lithologically different bedload from subsidiary streams inevitably resulted in a certain amount of “noise”. such samples were clearly not independent of one another both in a geochemical and statistical sense as they would have been if the stream segments belonged to the same order. variables the effects of lithology, conveyed through the lithological variables, were defined as a percentage of the drainage basin area which is occupied by a dominant rock type (rose et al., 1970; bonham-carter et al., 1987; peh, 1992). as the bedrock lithology of medvednica mt. comprises a variety of igneous, sedimentary and metamorphic rocks of different stratigraphic and tectonic settings, a simplified representation of lithology with as little as possible loss of useful information was necessary. for this purpose map data were scanned from the geological map of the medvednica mt. which, in turn, was compiled from the geological map of croatia (scale 1:100.000), sheets of zagreb (©iki∆ et al., 1978), ivaniê-grad (basch, 1983a), and varaædin (©imuni∆ et al., 1983). thus, a generalized lithological map was generated containing only eight lithological units which were broadly related to the corresponding stratigraphic nomenclature (fig. 3). these units were further utilized as lithologic variables which were specified as follows: lit1 predominantly parametamorphites; lit2 predominantly orthometamorphites; lit3 igneous rocks; lit4 predominantly mesozoic clastic rocks; lit5 predominantly tertiary clastic rocks; lit6 predominantly mesozoic carbonate rocks; lit7 predominantly tertiary carbonate rocks; lit8 quaternary sediments. the geochemical variables included a selection of 25 elements eight major and 17 minor and trace elements. the data required transformation with most of the elements in order to meet the assumptions of normality. for these elements log1 0 and log2 l o g a r i t h m i c transformations were used instead of the original data to reduce the skewness of distribution. only fe, al and k among major elements, and mn, ba and la among minor and trace elements are characterized by normally distributed data so that they were left non-transformed. 4.2. factor analysis the exploratory factor analysis is a powerful mathematical and statistical tool in handling a great number of numerical data. as a multivariate method, it facilitates the reduction, transformation and organization of the original data by the use of intricate mathematical techniques, which eventually results in a simple form of factor model. thus, a factor model represents, in a sense, a minimum or reduction model which explains correlations among observed data in as few terms as possible, ignoring minor influences and non-linear effects that may be present (miesch et al., 1966). in such a way it resolves the multivariate relations among variables in their correlations with a number of mutually uncorrelated, and hence independent, factors (davis, 1986), and portrays them in the space of the least possible dimensions. in other words, factor analysis creates the minimum number of new variables which are the linear combinations of the original ones with the same amount of information. if the original variables have significant linear intercorrelations, the first few factors will account for a large part of the total variance (mccammon, 1966). these then may be used to describe variation as observed in the original data and, subsequently, to explain the processes underlying the structure of the mathematical model. finally, for each sample, the factor scores can be computed which replace the values of the original variables. these characterize each sample and thus may be used in any subsequent classification or correlation analysis. factor scores can be particularly useful in creating the factor maps which display the areal distribution or influence of a particular factor, thus indicating predominant control of some natural process or processes. 5. results 5.1. selection and rotation of factors inasmuch as the factor analysis had been used as an exploratory method in geochemical investigations, the number of factors essential to the interpretation of the factor model was specified during the analysis. no assumptions about the investigated area with regard to the relationship between lithological types and stream 42 geologia croatica 54/1 sediment geochemistry has been established prior to analysis. this presented some problems as the primary idea of associating individual factors with specific lithology has not met the necessary criteria for factor extraction such as the variance rule, or kaiser’s eigenvalue>1 criterion, in particular. the two criteria effectively strain on the side of a plenitude of significant factors, indicating that the system’s variability is much dispersed through the system due to some qualities ingrained in the nature of data. in both cases, using the usual cutoff of 75% of total variance, or the λ>1 value (table 1), the nine factors could be retained, which is a solution that exceeds even the total number of lithologic variables. these examples raise certain ambiguities concerning a meaningful and clear-cut geological interpretation of the computed factor model. in contrast, according to the scree test as the third criterion for factor significance (fig. 4), the three or four factor solution will emerge as sufficient. this, conversely, does not leave enough room for defining a clear affinity between lithology and stream sediment geochemical composition. in the search for an optimum solution in the factor selection it was mandatory to reconcile these criteria with the concept of the system under investigation. thus, a cautious, but safe, compromise was chosen to overfactor rather than to underfactor the data in analysis. this took into account the general consensus of opinion prevailing among researchers (conway & haynes, 1973) that it is better to rotate too many factors than too few because the former case does not influence the structure of general factors accounting for greater portions of variance. pursuing the above suggestions, the nine factors were selected and rotated but only the first six were retained for further examination (table 1). the last three factors were ommited from further consideration due to the lack of sensible geological meaning that could be attached to them. these can be considered as a “residual heap” that should be left without explanation as only one or two geochemical variables, without due lithology, load highly on each factor. 5.2. a model the accepted solution is essentially a conceptual, systems-based model the primary objectives of which were: a) to establish the relationship between the bedrock lithology and geochemical composition of the stream sediments on the medvednica mt., and; b) to elucidate, if possible, the natural processes underlying that relationship. the model is presented in the form of a varimax rotated factor matrix (table 2) in which the six factors explain almost two thirds of the total system variability. as can be seen from table 1, although the first factor (f1) predominates and accounts for almost twice as much of the total explained percentage variance as the second (f2), the other factors show a slow decline in magnitude which is a sure indicator of weak factor eval %eval %cum f1 7.87 23.15 23.15 f2 3.99 11.73 34.88 f3 3.25 9.56 44.44 f4 2.69 7.91 52.35 f5 2.23 6.56 58.91 f6 1.73 5.09 64.00 f7 1.61 4.72 68.72 f8 1.46 4.31 73.03 f9 1.43 4.20 77.23 table 1 eigenvalues and respective factors (after rotation). a b fig. 4 a) plot of loadings on the first and second varimax rotated factors; b) plot of loadings on the first and third varimax rotated factors. 43halamiê, peh, bukovec, miko & galoviê: a factor model of the relationship between... interdependence among the observed properties (fig. 4). generally, the dominance of a single factor implies that the constraints operating within a system greatly decrease as the components tend strongly to cooperate toward the equilibrium conditions (chorley & kennedy, 1971; onesti & miller, 1974). however, this is not the case here judging from the slight drop in eigenvalue manifested from the second factor on, which suggests a complex influence posing mutual restraints within a system. it is inextricably woven into the geological (lithological in particular) fabric of the investigated area, but may also ensue from the accepted non-hierarchical pattern of the drainage basin network to which all studied relations converge. 5.3. labelling the factor axes among the six rotated factors the first factor f1 accounts for 23.15% of the total system variability. it is a monopolar factor (or slightly bipolar as far as th is concerned) which is essentially composed of variables positively correlating orthometamorphic lithology (lit2) to the major lithophile elements such as fe, ti, na and al. a group of minor and trace elements including v, co, th (negatively associated), zn, mn, as well as sc and y, also load on this factor. some of these elements particularly co share their variability with the second factor, which indicates that they may also derive their origin from some source other than orthometamorphic rocks eroded by the sampled streams. such a case implies a kind of interdependence between the two factors which are mathematically orthogonal (and thus independent) but conceptually related due to some unknown nonlinear responses among a number of system variables (norris, 1971). this is clearly suggested by a typical “horse-shoe” plot with co and zn as binding variables (fig. 4a). there is also a slight interdependence with the third factor owing to the relatively factors var f1 f2 f3 f4 f5 f6 h 2 lit1 -0.01 0.06 0.22 -0.16 0.81 -0.15 0.75 lit2 0.62 -0.14 -0.19 0.41 0.08 0.09 0.62 lit3 0.26 0.17 -0.40 -0.45 -0.10 -0.04 0.49 lit4 -0.13 0.18 0.19 -0.11 -0.75 -0.15 0.69 lit5 -0.06 0.13 0.02 0.02 -0.02 -0.07 0.03 lit6 -0.22 -0.18 -0.02 -0.12 -0.05 0.87 0.85 lit7 -0.42 -0.32 -0.05 0.49 -0.01 -0.11 0.53 lit8 -0.04 -0.13 -0.05 -0.06 -0.18 0.36 0.19 fe 0.86 0.38 -0.09 -0.09 0.14 0.02 0.91 ca -0.34 -0.12 -0.35 0.70 0.16 0.22 0.82 mg 0.38 0.29 -0.22 0.14 0.07 0.69 0.78 ti 0.91 -0.01 -0.06 -0.14 -0.07 0.00 0.85 al 0.70 0.36 0.25 -0.28 0.09 -0.14 0.78 na 0.81 -0.12 -0.13 -0.05 0.14 -0.19 0.74 k -0.21 0.21 0.68 -0.30 0.09 -0.19 0.69 p 0.29 0.11 0.28 0.31 0.66 0.01 0.71 cu 0.40 0.69 0.12 -0.02 -0.01 -0.01 0.65 pb -0.08 0.10 0.19 -0.06 -0.00 -0.04 0.06 zn 0.50 0.43 0.17 0.00 0.23 0.06 0.53 ni -0.00 0.90 0.09 0.03 -0.09 -0.03 0.82 co 0.64 0.69 0.04 -0.19 0.01 -0.05 0.92 mn 0.49 0.48 0.14 -0.14 0.14 0.05 0.53 as 0.03 0.45 -0.11 -0.29 0.31 -0.18 0.43 th -0.54 0.08 0.71 -0.18 0.04 -0.08 0.84 sr -0.05 -0.05 -0.17 0.84 -0.03 -0.18 0.78 v 0.88 0.35 -0.11 -0.18 -0.01 0.03 0.94 la -0.38 -0.05 0.80 -0.01 0.16 0.03 0.81 cr 0.44 0.74 -0.06 -0.18 -0.08 -0.03 0.79 ba -0.13 0.17 0.51 -0.02 0.09 -0.18 0.35 zr 0.15 0.38 0.30 -0.27 -0.41 0.10 0.51 y 0.80 -0.05 -0.14 0.30 -0.05 0.15 0.77 nb 0.35 0.05 0.65 -0.32 -0.17 0.00 0.68 sc 0.89 0.24 -0.23 -0.04 0.08 -0.04 0.91 table 2 varimax rotated factor matrix. 44 geologia croatica 54/1 high loadings of th on both f1 and f3. despite the peculiar behaviour of the trace elements, the firm correlation between major elements and lithology can be established so that f1 can be properly referred to as the factor of orthometamorphic rocks. the second rotated factor f2 explains a further 11.73% of the total information in the data matrix. it is largely concerned with positive associations within a set of trace elements of litho-chalcophile characteristics, such as ni, co, cr, as well as chalcophile cu (zn and as), which occur mostly in the form of sulphides (ore minerals). a notable absence of the major elements, as well as non-appearance of a direct link with any of the lithologic variables (table 2) suggest an undefined type of parent rocks as the source of their origin. some unclear ties with lithology can be deduced from the shared loadings of co (and, less characteristic, of mn, zn and cr) on both f1 and f2, which hints at orthometamorphic primary rocks, bearing scarce sulphidic ore veins, as their partial provenance. also, possible effects of industrial contamination cannot be ruled out due to a number of active quarries on the footslopes of the medvednica mt. owing to its lithological ambiguity, the second factor f2 should be labelled provisionally as the non-lithologic factor . the third factor f3, explaining a further 9.56% of the total variance, is of a bipolar nature on the grounds of the negative relationship that unites the set of geochemical variables k, th, ba, la and nb with lithologi cal variable lit3 standing for igneous rocks. this is a rather peculiar situation as one must associate the occurrence of these elements with the apparent absence of indicated lithology and vice versa, as though the relationship is based on mutual aversion. it is aggravated, further, by a quite unimpressive loading of lit3 (-0,41) on this factor, which commands caution in its interpretation. thus, a safe approach to the probable solution would be that the occurrence of the k-ba-thla-nb set is somehow limited in the range of drainage basins dominated by the igneous rocks, rather than enriched in those covered by other types of lithology, although the reasons for such behaviour remain unknown. perhaps this picture reflects the sharp contrast between the areas of erosion and deposition reflecting the situation when, due to the geomorphologic, hydrologic, hydraulic and other drainage basin/stream channel processes, the geochemical assemblage of stream sediments finds itself in “alien lithological surroundings” downstream. thus a “negative” image in the factor model might have been created. the similar, but much simpler, example can be encountered with f1 where all relevant geochemical variables are negatively associated with the weakly loaded lit7 (carbonate rocks). as the orthometamorphites are the dominant lithology, no problems with factor interpretation arise in that case. here, again, following the relationship between geochemical and lithological variables, the factor f3 could be correspondingly labelled the f a c t o r of igneous rocks . with the fourth factor f4 commences a series of factors more easily explainable in terms of the relationship between geochemical composition of stream sediment samples and lithology of adjacent drainage basins. the reason for this is a considerably reduced number of variables loading significantly on each factor which greatly simplifies the factor structure. the first of these, f4, accounts for 7.91% of the total variance examined. as can be seen from table 2, it is dominated by only two geochemical variables, namely ca and sr, that covary in a positive relationship with dominant lithological variable lit7 standing for the tertiary carbonate rocks. the explanation of this factor is, thus, straightforward and it can be readily described as the factor of tertiary carbonate rocks . a weak relationship with lithologic variables lit2 (+) and lit3 (-) also exists suggesting that a minor portion of ca and sr might be derived from the orthometamorphic lithology, but essentialy from the areas devoid of igneous rocks. the joint plot with the first factor f1 (fig. 4b) is added to portray the mathematical and conceptual independence of the first factor as opposed to the clear f1-f2 interrelationship (fig. 4a). the fifth factor f5, which explains another 6.56% of the total variance, is of a strongly bipolar nature with exception to earlier cases that two lithologic variables, lit1 and lit4, stand against each other, while the single geochemical variable p affiliates with the former. this may be interpreted as a result of enrichment with accessory phosphoric minerals, such as apatite, in the zone of predominance of parametamorphic rocks. in contrast, stream sediments collected in the area predominantly overlain by mesozoic clastic rocks can be seen to be deficient in phosphorus. a weak loading of zr that associates with lit4 may be instructive as to the primary composition of the mesozoic clastic rocks. this factor can be interpreted as the factor of parametamorphic rocks . the sixth factor f6 is the last in the series of significant factors which accounts for only a small fraction (5.09%) of the total variance. this factor is the simplest of all, being highly loaded with only two variables. its structure is marked by a high positive association between a single geochemical and a single lithological variable, which leaves no room for doubt as to the origins of this correlation. the mesozoic carbonate rocks, notably dolomites of the middle and upper triassic (lit6), are indicated as the primary source of mg in the stream sediment. this factor can be easily identified as the factor of the mesozoic carbonate rocks . some variables in the model do not greatly participate in explaining the accepted factor solution. this can easily be seen from the fraction of the total variance carried by each variable, which is explicable by all six factors in the model. this value, known as communality h2, diverges widely from variable to variable. close examination of the factor matrix (table 2) reveals that lead partakes in the common variance considerably less 45halamiê, peh, bukovec, miko & galoviê: a factor model of the relationship between... than 50% (h2=0,50). this is also true for lithologic variables lit5 and lit8, which means that the tertiary clastic rocks and quaternary sediments do not help much in clarification of the relationship between underlying bedrock lithology and geochemical composition of the stream sediment. the reasons for geochemical variables not being “adopted” by any of the explained factors in the factor model may vary. one of them is probably built in analytical methods that set the concentration values for the elements, such as zr for example, near the detection limit, causing the possible loss of the larger portion of a variable’s innate variance. others can truly refer to the circumstances that are inherent to the observed data, announcing that some elements, such as pb, have little to do with the system investigated, having entered from outside, perhaps in a form of a pollutant. this, however, is not grounded in a factor model and in this stage belongs wholly to the realm of speculation. a number of variables have moderate communalities with magnitudes vacillating around 50% of the model explanation; mn, zn, cu amongst others. hence, these partake significantly in the common solution and should not be discarded. yet, as a rule, their loadings are scattered on two factors with greately reduced values on both, which decrease their variability in the factor explanation. manganese is a good example, and the first two factors are notable in this sense. 6. factor maps after determining the geological meaning underlying the relationships among original variables, it was of interest to observe the areal distribution of variances, and possible trends hidden behind the respective factors. thus, the construction of the factor maps proved to be essential for the geological factor study as they allowed the lithological-geochemical domains to be related to other geological characteristics in the investigated area. for each stream sediment sample a factor score was computed which represents the “amount” of a particular factor in that sample, that is, the drainage basin from which it was collected. the range of factor scores delineates the shift of this amount from the mean value expressed in units of standard deviation. in all cases, except for the sixth factor (f6), the factor scores roughly tend to be normally distributed according to the applied k-s test, and therefore the values of factor scores were grouped into eight classes. these are arranged with regard to the so-called 1σ-, 2σ-, or 3σrule (deviation from mean), which applies to the standard normal distribution curve of µ=0 and σ=1. the factor score value for each sample, entering one of the classes, was attached to the corresponding drainage basin and presented on the map. as can be seen from the factor maps, a simple but instructive display of drainage basins distinguishes the sections of increased or decreased “amounts” of factors over the study area. what is particularly informative about the classes is that they indicate the basins where the specific factor shows the variance which may vacillate within or outside the range of the background values. thus, the basins falling within the limits of µ ± 1σ ( 1 < f s < 1 ) tend to show the background tendencies with regard to the variable assemblage loading significantly on the specific factor. naturally, disposition of the factor scores over the “threshold”, in the area greater than one (>1σ), or less than one (< -1σ) standard deviation, indicates the drainage basins where the factor scores suggest either enrichment of a particular geochemical association in relation to lithology, or its deficiency, respectively. these values can be considered anomalous in the exploratory analysis, at least as the first approximation. for a normally distributed population, factor score values higher than background, but fixed within the range of the mean plus 2σ (1<fs<2), are usually termed nonsignificant anomalies, while those greater than the mean plus 2σ (2<fs<3) can be considered as significant anomalies (rose et al., 1979). the values higher than 3σ are obviously outliers. these considerations also apply to the negative values, although in geochemistry the negative “anomalies” are seldom accounted for. 6.1. description of factor maps the significant anomalies (>2σ) for the first factor f1 are spread around the source areas of the medveπêak, bliznec, markuπevac and »uëerje valleys (fig. 5). these areas are mostly composed of green orthoschists, metagabbros and metadiabase, and occasionally by amphibole schists (©iki∆ et al., 1979; pami∆ & injuk, 1987; belak et al., 1995). the major elements fe, ti, al and na, which are positive correlated to lit2 (orthometamorphic lithology) (table 2), are predominantly associated with ferromagnesian minerals and plagioclase in the related rocks. the minor and trace elements v, co, zn, mn, sc and y also derive their origin from orthometamorphic rocks (the protolith is represented by basic volcanics, basic tuffs and tuffites) in the same area which, as a rule, are distinguished by the increased content of the same elements (rösler & lange, 1976; rösler 1981; pami∆ & injuk, 1987). as cobalt also contributes to the factor f2 of no distinctive lithologic provenance, it may indicate technogenic pollution of the stream sediment brought about by the quarrying of basalt rock on the northwestern slopes of medvednica. thorium, being negatively associated in this case, possibly reveals the enhanced migration of this element from the lit2 group of rocks due to metamorphic processes. as a result, its “accumulation” is associated with the negative anomalies (<2σ) in the low lying drainage basins on the western and easternmost parts of zagrebaëka gora and over most of the zelinska gora. the anomalies of the “non-lithologic” factor f2 are scattered in a very irregular pattern over a few drainage 46 geologia croatica 54/1 fig. 5 factor map of the first factor (f1). fig. 6 factor map of the second factor (f2). 47halamiê, peh, bukovec, miko & galoviê: a factor model of the relationship between... basins: in the source area of the kaπina and bistra streams, in the central part of the moravëe stream, and in the lower portion of the burnjak stream (fig. 6). the kaπina and moravëe anomalies occur in the area formed of the tertiary clastic rocks (ottnangian). these rocks are represented by a packet of irregularly alternating polymict conglomerates, gravels, coarse-grained sands and sandstones lying discordantly over the older rocks (basch, 1983a). they derive their origin from the intensively eroded mesozoic bedrock (upper and lower palaeozoic, triassic, jurassic-cretaceous). conglomerates contain, in part, pebbles of spilite, diabase and basalt (paveli∆, 1998) the basic rocks with increased content of ni, cr, co, v and cu. in addition, these rocks are also host to fragments of ultramaphites (serpentinites) (koch, 1904). the anomaly in the bistra stream (fig. 6) is very probably associated to the increased concentrations of co and v from industrial contamination of the local area (the quarry of kraljev vrh). the negative association of elements k, th, la, ba i nb with lithology lit3 (igneous rocks) on factor f3 (table 2) is altogether expected, since the basic igneous rocks are mostly classified as lit3. it is well known that the increased average content of k, th, la, ba and nb is more characteristic for acid igneous rocks. as a consequence, it is only natural that negative anomalies can be traced on the northwestern slopes of the medvednica mt. which are predominantly composed of basic igenous rocks (fig. 7). positive anomalies of f3 are associated with catchment basins with mostly parametamorphic bedrock (southern slopes of zagrebaëka and zelinska mts.) and with mesozoic non-carbonate bedrock (the lower triassic clastic rocks on the northwestern section of zagrebaëka mt. and in the area of ©agudovec forest). these indicate that the parent material for the genesis of the parametamorphite complex and later clastic rocks of the mesozoic period might have been derived either from older, more acid igneous rocks, or from older sedimentary rocks with a higher content of minerals characteristic of acid igneous rocks. the map of f4 displays a concentration of the highest anomalies within the cathments lying on predominantly tertiary carbonate bedrock bioclastic limestones and algal limestones (fig. 8). the increased content of characteristic elements ca and sr obviously originates from the same complex of rocks which occupy limited patches on the westernmost tip of zagrebaëka mt. (badenian and pannonian vrsaljko, 1999), but spreading more frequently in the zone of ©agudovec forest and the northeastern part of zelinska mt. concerning a weak positive relationship of ca-sr combination with a lit2 lithology may also indicate that some portion of these elements in the stream sediment geochemistry originated in the orthometamorphic complex (e.g. plagioclases). higher score values of 1<fs<2 indifig. 7 factor map of the third factor (f3). 48 geologia croatica 54/1 fig. 8 factor map of the fourth factor (f4). fig. 9 factor map of the fifth factor (f5). 49halamiê, peh, bukovec, miko & galoviê: a factor model of the relationship between... cate the area with orthometamorphic bedrock. the factor map of parametamorphic lithology displays a consistent zone on the southern slopes of zagrebaëka mt. and zelinska mt. (from the medveπêak stream on the southwest to the mala reka stream on the farthest northeast) with increased factor score values (fig. 9). this area is mostly built of parametamorphic rocks, while the anomalous values in the cumbaina valley are probably inflated due to presence of diabase veins, enriched in apatite, within the parametamorphic complex. the northwestern parts of zagrebaëka mt. together with the ©agudovec forest area are characterized by extremely low factor score values. these areas conform very closely to the domain of mesozoic clastic rocks (fig. 2). as can be seen from the factor model (table 2) this is an area with increased concentrations of zr in stream geochemisrty, indicating that zirconium might have been a significant constituent of the detritus material in lit4 before its redeposition in the valleys. the factor map of mesozoic carbonate rocks f6 (fig. 10) shows a few confined zones of extremely high factor score values, thinly dispersed over the northern slopes of the medvednica mt. these positive anomalies are associated with dolomites and dolomitized limestones of the middle and upper triassic overlying the westernmost portion of zagrebaëka mt. (ponikve) and the ©agudovec forest area. for the most part of medvednica mt. the factor scores are evenly distributed (-1<fs<1) indicating that mg partakes in all lithologies (except lit6) with low variability. 7. conclusions many regional and local studies based on extensive use of stream sediment as the most convenient sample medium have been orientated to mineral exploration and contamination assessment. more rarely, they were focused on some particular topic of more local significance, such as the relationship between the stream sediment geochemistry and adjacent drainage basin lithology. the latter case, including this study, was almost always aimed at elucidating the interdependence of different geological processes which may sometimes be screened by the products of forcible human activity. here, we constructed a tentative model which related the geochemical composition of active stream material in a number of catchments on the medvednica mountain, to a broadely defined bedrock lithology which had served as the parent material. the model is a system based, factor model which synthesized eight lithological and 25 geochemical variables (major, minor and trace elements) and reduced their relationships into six geologically meaningful factors. five of these divulged a definite relationship between geochemistry and lithology. the sixth can be identified as “non-lithologic”. fig. 10 factor map of the sixth factor (f6). 50 geologia croatica 54/1 taken together they explain almost two-thirds of the system variability (64%). geochemical variables fe, ti, na, v, co, zn, mn, sc and y positively correlate to the orthometamorphic lithology lit2 on the first factor f1, except th which is negatively associated. this grouping is a result of geochemical composition characterizing the orthometamorphic rocks. the absence of positive correlation of the same variables to basic igneous rocks (with a very similar geochemical composition as the former) could be considered as the effect of the proportionately lower occurrence of igneous rocks in total drainage basin lithology (the effect of dilution igneous-sedimentary complex!). the second factor f2 with ni, co, cr, cu, (zn), and (as) does not directly associate with any of the proposed lithologic units. this may be either the result of the strong mixing of different lithologies within the stream sediment material (e.g. co is as strongly loaded to this factor as to the f1) or the enrichment via the ore minerals appearing in the orthometamorphic complex. the third possibility is seen in contamination (quarry, vineyards, etc.). as anticipated, the elements k, ba, th, la and nb on the factor f3 (factor of igneous rocks) are negatively associated with igneous lithology lit3. the anomalous factor score values over the areas with parametamorphic lithology (lit1), as well as mesozoic carbonate lithology (lit4), indicate the older, more acid igneous rocks as the source material in their formation. the fourth factor f4, hosting two dominant geochemical variables, ca and sr, and only one lithologic variable, the tertiary carbonate rocks, in mutually positive correlation, entirely conforms with the chemical composition of the latter (bioclastic and bioaccumulated limestones). phosphorus as the dominant element in the f5 (factor of parametamorphic rocks) is related to the accessory component in these rocks (apatite). negative correlation of this element to the mesozoic clastic rocks (lit4) is probably imposed by their original composition. the mesozoic carbonates are mostly built of dolomites and dolomitized limestones which is quite clear in f6 from the high positive correlation of mg with lit6 lithological group. acknowledgments the authors would like to express their gratitude to dr. u. fügedi for thoughtful reviews and constructive comments which helped to clarify some thoughts in an early draft of this manuscript. thanks are due to dr. l. ódor who also read an earlier version of the paper and kindly assisted in further dissemination of its core ideas. finally, this study was funded by the ministry of science and technology, republic of croatia, project no.: 01810106, “the basic geochemical map of the republic of croatia”. 8. references abbey, s. (1983): studies in “standard samples” of silicate rocks from 1969-1982.geological survey of canada, paper 83-15, 1-114. basch, o. (1983a): osnovna geoloπka karta sfrj 1:100.000. list ivaniê grad l33-81 (basic geological map, ivaniê grad sheet).inst. za geol. istraæ. zagreb (1969-1976), savezni geol. zavod beograd. basch, o. (1983b): osnovna geoloπka karta sfrj 1:100.000. tumaë za list ivaniê grad l33-81 (geology of the ivaniê grad sheet).inst. za geol. istraæ. zagreb, savezni geol. zavod (1980), beograd, 66 p. belak, m., pami∆, j., kolar-jurkov©ek, t., peckay, z. & karan, d. (1995): alpinski regionalnometamorfni kompleks medvednice (sjeverozapadna hrvatska) (alpine regional metamorphic complex of the medvednica mt. nw croatia).1. hrvatski geol. kongres, zbornik radova, 1, 67-70, zagreb. bonham-carter, g.f., roger, p.j. & ellwood, d.j. (1987): catchment basin analysis applied to surficial geochemical data, cobequid highlands, nova scotia.j. geochem. explor., 29, 259-278. chorley, r.j. & kennedy, b.a. (1971): physical geography: a systems approach.prentice-hall international inc., london, 370 p. conway, d. & haynes, k.e. (1973): a geographical factor analysis model: some transatlantic reflections.area, 5, 106-109. darnley, a.g., björklund, a., bølviken, b., gustavsson, n., koval, p.v., plant, j.a., steenfelt, a., tauchid, m., xie, x., garrett, r.g. & hall, g.e.m. (1995): a global geochemical database for enviromental and resource management: recommendations for international geochemical mapping.final report of igcp project 259, 2nd revised edition, paris: unesco, 122 p. davis, j.c. (1986): statistics and data analysis in geology.2nd ed., john wiley & sons, new york, 646 p. –ur–anovi∆, æ. (1973): o paleozoiku i trijasu medvednice (zagrebaëke gore) i podruëja dvora na uni na temelju konodonta (about the paleozoic and the triassic of medvednica mt. and the area near dvor na uni on the basis of conodonts).geol. vjesnik, 25, 29-49. gladney, e.s. & burns, c.e. (1984): 1982 compilation of elemental concetration data for the usgs geochemical exploration reference samples gxr-1 to gxr-6.geostandard newsletters, 8/2, 119-154. govindaraju, k. (1989): compilation of working values and sample description for 272 geostandards.geostandard newsletter, 13, 1-28. koch, f. (1904): serpentinsko kamenje zagrebaëke i kalniëke gore.nast. vjesnik, 13/2, 217-220, zagreb. 51halamiê, peh, bukovec, miko & galoviê: a factor model of the relationship between... mccammon, r.b. (1966): principal component analysis and its application in large-scale correlation studies.jour. geol., 74, 721-733. miesch, a.t., chao, e.c.t. & cuttita, f. (1966): multivariate analysis of geochemical data on tectites.jour. geol., 74, 673-691. norris, j.m. (1971): functional relationships in the interpretation of principal component analysis.area, 3, 217220. onesti, l.j. & miller, t.k. (1974): patterns of variation in a fluvial system.water resources research, 10, 11781186. ottesen, r.t., bogen, j., bølviken, b. & volden, t. (1989): overbank sediments: a representative sample medium for regional geochemical mapping.jour. geochem. expl., 32, 257-277. pami∆, j. & injuk, j. (1987): petroloπko-geokemijske karakteristike ortogrinπista zagrebaëke gore u hrvatskoj (petrology and geochemistry of orthogreenschists from mt. zagrebaëka gora in croatia).geologija, 28/29 (1985/86), 239-254, ljubljana. paveli∆, d. (1998): taloæna evolucija slatkovodnog donjeg i srednjeg miocena sjeverne hrvatske na temelju analize facijesa.unpublished phd thesis, university of zagreb, 149 p. peh, z. (1992): factor model of the geomorphological system of a part of northwestern croatia.geol. croatica, 45, 163-172. rose, a.w., dahlberg, e.c. & keith, m.l. (1970): a multiple regression technique for adjusting background values in stream sediment geochemistry.econ. geol., 65, 156-165. rose, a.w., hawkes, h.e & webb, j.s. (1979): geochemistry in mineral exploration.2nd ed., academic press, london, 657 p. rösler, h.j. (1981): lehrbuch der mineralogie.veb deutscher verlag für grundstoffindustrie leipzig, leipzig, 833p. rösler, h.j. & lange, h. (1976): geochemische tabellen.veb deutscher verlag für grundstoffindustrie leipzig, leipzig, 674 p. ©iki∆, k. (1995): prikaz geoloπke grae medvednice.in: ©iki∆, k. (ed.): geoloπki vodië medvednice. institut za geoloπka istraæivanja & ina industrija nafte d.d., 7-30, zagreb. ©iki∆, k., basch, o. & ©imuni∆, a. (1978): osnovna geoloπka karta sfrj 1:100.000. list zagreb l38-80 (basic geological map, zagreb sheet).inst. za geol. istraæ. zagreb (1972), savezni geol. zavod, beograd. ©iki∆, k., basch, o. & ©imuni∆, a. (1979): osnovna geoloπka karta sfrj 1:100.000. tumaë za list zagreb l38-80 (geology of the zagreb sheet).inst. za geol. istraæ. zagreb (1972), savezni geol. zavod, beograd, 81 p. ©imuni∆, an., pikija, m., he∆imovi∆, i. & ©imuni∆, al. (1981): osnovna geoloπka karta sfrj 1:100.000. tumaë za list varaædin l33-69 (geology of the varaædin sheet) .inst. za geol. istraæ. zagreb (1982), savezni geol. zavod, beograd, 75 p. ©imuni∆, a., pikija, m. & he∆imovi∆, i. (1983): osnovna geoloπka karta sfrj 1:100.000. list varaædin l33-69 (basic geological map, varaædin sheet).inst. za geol. istraæ. zagreb (1971-1978), savezni geol. zavod, beograd. ©inkovec, b., palinka©, l. & durn, g. (1988): rudne pojave medvednice (ore occurrences on the medvednica mountain).geol. vjesnik, 41, 395-405, zagreb. thalmann, f., schermann, o., schroll, e. & hausberger, g. (1989): geochemischer atlas der republik österreich 1:1.000.000.arbeitsgemeinschaft voest-alpine & bundesversuchs und forschungsanstalt arsenal & geologische bundesanstalt, wien, 141 p. vrsaljko, d. (1999): the pannonian palaeoecology and biostratigraphy of molluscs from kostanjek medvednica mt., croatia.geol. croat., 52/1, 9-27, zagreb. manuscript received november 21, 2000. revised manuscript accepted april 23, 2001. geol. croat. 50/1 17 25 7 figs. 2 tabs. zagreb 1997 glauconitic materials from lower miocene macelj-sandstones of the hrvatsko zagorje, north-western croatia neven tadej, dragut in slovenec, josip tisljar anci [vica inkret key words: macc lj -sandslones, gl auconitic mate rials, g lauconite, xrd powder patte rns, chemical com­ pos ilion, thermal analysis, i-irvatsko zagorjc, cremia. abstract the lowe r mi ocene macc lj -sands[oilcs, from (ile western part of hrvatsko zagorje, arc green in colour with variabl e amounts o f glau­ conit ic gra ins. thi s paper presents the results of mineralogical and some petrological ana lys is of three char:lclcris tic sam ples of these sandslones. the natura l sandstone sampl es were ana lysed by polarisi ng microscope and by x -ray powcler diffraction (x rd). a fter separation, the pure or ,\hnos( pure g lauconitic material s were analysed by xrd, chemi c,\1 ililal ys is and th enn;11 analysi s (tg , dta and dtg). the res ults show variati on, not onl y in (h e gl au conit ic mat erial of the sandstone samples. but a lso within individ u<ll samples. the amount o f smeclite layers varies fro m < 5% to approximatel y 40% de pendi ng on the degree of order and the stage of gl<lllconilc cvolution. th is is indi ­ cated by th e contents o f k, ai, fe , ad sorbed water and cat ion exc hange capacity as well as xrd powder palle rns. 1. introduction t he macclj -sand stones arc located in the wes te rn pari o r th e hrvat sko zagorje reg ion in north -weste rn croatia, and in adjacent eastern sl ovenia. th e nam e macclj -sandstoncs has been lised ever since they were desc ri bed by gorj anovic-kramberger ( 1904) in the ex planatory tex t for the geological map. sheet rogat cc-kozje. as "g recnish-grey turfaceou s sand­ stones indicating a shallow -marine environm ent". these sand ston es o lli c rop in th e hrvatsko zagorje region be tween mt. s trahinsciea and mi. ivansc iea in the south, and mt. ravna gom in the north, covering a tota l surface area of about 130 km2 (fig. 1). this rorl1la ~ lion is prcdominantly com posed or shallow-marine clas tics, sevc ral hundred metres thick, characte ri sed by glauconitc-bcaring sancis tones with subord inate quanti ­ ties or conglome rate, tultiti c sandstone, tuff, and c lay (tisljar & sim un ic, 1978; sim unic ct ai. , 1990). the strati graphic position of these sedimentary rocks is faculty o f mi ning. geology and petroleu m eng ineeri ng, unive rsi ty o f zagreb, pieroll ijeva 6. iir ioooo zagreb, crolilia. lower miocene ( from egerian to karpathian), dur ing which sedimentation creating barrie r sand bars predom ­ in at ed , occasionally interrupted by dacite-andes it e explos ive volcani sm. thc volcanism began to cease by the end of this period , and a new transgression and tec­ tonic movements prevented deposition of c lastic sedi ­ menls, and increased carbo nate sedimentation (s im u­ nrc ct ai. , 1990). the mace lj-sandstones are of homogcnous mineral composition with vari ation expressed through grain size and re lati ve pe rcent ages of vol cani c las ti c mate rial , matrix and ce ment. the de trital composition indicates sou rce arcas composed mostly of sedimentary rocks and schists. in the tultitic sandstones the dis tinction between resedimentcd and directl y depos it ed volcaniclastic mate ri a l is ambiguous due to inte ns ive chloriti za ti o n and glauconitization. 'the matrix composition and tex­ ture seem to indicale direc t deposit ion of volcanic ash, which was produccd by periodic e ruplions in thc adja­ cent areas (tisljar & simunic, 1978). th is pape r represents introdu c to ry work in the in ves ti ga tion of glauconitic mate ria ls of the macelj ­ sandstones and the ana lys is of these matcrial s from three typical sandstone samples. sample m3 was taken from the outc rop (l owe r part of the lowe r miocene mass ive macelj-sandstones) on the durmanec-macelj road , ncar the borde r be twcen croatia and sloveni a (the border cross ing maee tj). sample rg was obtained from a drill core (at 31.5 m depth) from an exploratory we ll s ituated south-wes t o f the village of strupari , soulh o f mt. ravna gora. samp le mt was take n from an o ut­ crop (uppe r part of the lower mioce ne c rossbedded macelj -sandslones) on the road ncar donji mace lj. the sample locations areyresellte? on ri g. i. analogous to srodon 's ( l 984) definition for ill it ic materials, in th is paper we used the te rm glau­ conitic ilwte rial to refe r to both g lauconite and to inte r­ stratifi ed glauconite-s mectite, as we ll as to the ir mi x­ ture. 2. description and mineral compo­ sitions of sandstone samples th e sa mples of the macelj~sands t ones wc re a na~ lysed by polariz ing microscope and xray powder dif­ fraction (xro). 18 legend: strohinlcica mt. ., mocelj sandstones" (lower mfocene) sample m3 is a glauconitic sandstone com posed of poo rl y sorted , mos tly angular, rarely subrounded finc­ grai ned lo medium -grained particles (0.3-0.7 mm in size). t he det ritus consis ts mostly of rock fragme nts with subordinate undu lato ry quart z, and very rare fe ldspars. the most comlllon accessory mine ral is gar­ ne t which is accompan ied by subordinate lourmaiinc, apatite , muscov it e, biot it e and limonite aggrega tes . a green ish g lauconiti c mat ri x is predominant, together with dense chlorite-seric ite aggregates, which are prob­ ably a diagenet ic product of clays ri ch in organic impu­ ri ties. caleite ceme nt occurs sporadicall y in intergranu­ lar pores. rock fragment s are mostl y grai ns of quartzite , chert , c rystalline sch is ts, and occas ionally m<lcrocrystallinc dolomite. the undulatory ex tinction or q uartz grains indi cates it s me tam orphi c orig in. fe ldspars are almos t completely seric itized ; rare relict grains d isplay zoning or dense polysynthe tic twinning and corroded edges. fragments of extrusive rocks, with plagioclase phenocrysts and micas produced by dcvitri­ fi ca tion of volca nic glass were al so iden tifi ed. some fi ssures in the detri ta l grains are s lightly greenish. glauconitic mate ria l occurs in two basic form s : as de trital grains and as the matrix (fig. 2a). less com­ mon ly, thc dc trita l g lauconi tic material occurs as well rounded g rains composed of c ryptocrys ta lline "grape like" darkgreen aggregates . most of the g lau conit ic matrix mate rial fills intergranular pores, is much brighter in colour and occurs as cryptocrysta ll ine, platy­ shaped aggrega tes, with s ingle minute se ricite and chlo­ rit e plates within the g lauconi ti c mate ria l. the g lau­ conit ic matri x is not evenly dis tributed throughout the rock, but is rather concentrated in the shape of laminae and inte rl aye rs w ith in the sandstone. ofte n the re are laye rs composed nearly e ntirely of glauconitic matrix and interlayers in whi ch the glaucon iti c mate rial is a lmost absent. the glauconi tic mat rix di splays features of plastic defofmation and compact squeezi ng (e .g. sand grains which are nea rly complete ly wrapped in glauconitic material). tu ff (lower miocene) geologi .. cro~tic :l , oil fig. 1 location map (modified from simunic el a\.. 1990). sample rg is very s imi lar to sample m 3, partic u­ larly in the compos ition o f de trital grains , whi ch are better sor ted, subrounded to rounded , wi th s ize charac­ teri st ics of medium-grained to coarse-grained sand. the glauconitic mate rial occup ies inle rg ranular pores in the pans that are c las t or matrix supported. in contrast to samples m3 and mt, there is no glauconitic materia l in the form of detrital gra ins. the g lauconiti c mate rial occurs in the matrix and it is most probably a produc t of glaucon itization of fin e volcanic ash of glass. thc glauconitic materia l displays feat ures of sed­ imcntati o n under semipi astic condit ions. t extura ll y, three types of the grccn glauconiti c matri x can bc d is­ tingui shed: darkgreen grapy aggregates (fi g. 2b), ye l­ lowgreen, mo re or less homogeneolls c ryptoc rystalline aggregates, with weak pl eoc hro ism and with sparse mica, and fibrou s gree n agg regates with s trong pleochroism which are probably produced by g laliconi­ ii zation of c hl o rite (fi g . 2b). [n ihc rg sands io ne, a ltered gra ins are preselll in which cryptoc rys ta lline quart z domina tes and whi ch are s lightly green along fi ssures (fig. 2b) . sample mt is a crosslaminated nne-g rain ed to medium-grained sandstone, wi th mai nly angular to sub­ rounded grains, rare ly with rounded grains, averaging 0.1 -0.4 mm in size. the sandstone is composed of s ili ­ c ic las tic gra ins, glauconit ic mate ri al and matr ix w it h sporadi c calc ite cem ent. in contrast to the prev iously descri bed samples, silicic lasts of mt sandstone consis t of angula r to subangu lar quartz fragments mainly with undulat ory extinction. c las ts of quartzi te, che rt and low-me tamorphic to med ium -me tamorphi c g rade schis ts (quartz-sch ists) are common, wh ile to a lesser ex tent fragme nts of gneiss, mica-schis t, dolom itc, si lt­ stone and sodic plagioclase are also present. 1n thi s sampl e, det rital f1akes of muscovi te are quite frequently observed. glauconitic material occurs mainly in the intc rgran­ lilar pores of si jiciclas ts as cryptoc rysta ll ine matri x or as mic rocrysta lline, platy ye llow-oli ve-green aggregates tadcj, slovcncc, tisljar & inkret: glauconitic materials from lower miocene .vl:jcelj-sandstones ... 19 c fig. 2 a) dark green grape-like detrilie glauconitic material and light green glauconitic matrix filling intergranular pores. thin section of sample m3; i n, photo length 1.36 mm. b) glauconitic matrix in the form of dark-green grape-like clusters and green fibrolls clusters. light green glauconitic material coatings in quartz rractures arc also present. thin section of sample rg: in, photo length o.s6 mm. c) laminae with glauconitic matrix. thin section of sample mt: i n, photo length 1.36 rum. d) detritic grape-like dark-green glauconitic grain . thin section of sample mt; i n, photo length 0.86 mm. (fig. 2c). the structurc and rc lationship of the glau­ conitic material with these siliciclasts indicates that the ground mass was originally composed of fine volcanic ash or semilithified glassy tuff. the glauconitic mass frequently contains fine-dispersed pyrite and organic matter. the glauconitic matcrial matrix is commonly concentrated within single laminae. glauconitic materi­ al rarely occurs in the form of spherical and grapelike grains (fig. 2d), which can be distingu ished from the glauconitic matrix due to their more in tense green colour, and the lack of any internal microtexture except cryptocrystalline and microcrystalline aggregates. despite some small differences, all the examined sandstones (m3, rg and mt) according to petti­ john et al. (1972) can be classified as lithic graywack­ cs. xrd analysis, carried out 011 bulk-rock samples, shows that quartz is the dominant mincral in sample m3, which also contains a considerable amount of cal­ cite, subordinate plagioclase and k-feldspar, two chem­ ically different types of dolomite, and minor quantities of muscovite and siderite. the amount of glauconitic material is very small. the mineral composition of sam­ pic rg diffcrs from the m3 sample since it contains several times the amount of glauconitic material and considerably less calcite. sampierg also contains two different dolomite types, some more plagioclase, a little chlorite, muscovite, and no siderite. thc highest content of quart z and muscovite arc prescnt in sample mt which also contains dolomite and some calcite, plagio­ clase, k-feldspar, chlorite and haematite. the content or glauconitic material is higher in sample mt than in samplc m3. 3, separation of pure glauconitic material and experimental methods xrd patterns of the analysed bulk-rock sandstones samples could not be used to idcntify the glauconitic material due to the relatively small amounts prcscnt in th e sam pl es. separation of pure glauconitic material was carried oui, 10 enable further determ inatio n to be undertaken. after fragmentation, sievi ng and water washing, the 0.1 -0.2 ml11 and 0.2-0.315 111m fractions were enriched in glauconitic material. these were later magnetically separated by a frantz isodynamic separator. the mag20 netic glauconitic fractions were obtained at i = 0.400.55 a (labelled mt/l , m3/l and rg/l) and at i = 0.55-0.60 a (labelled m3/2 and rg/2), and were finally purified by hand-picking under the binocular micro­ scope. other magnetic fractions of analysed samples contained more impurities consist ing of other sandstone mineral constituents mixed with glauconitic material. after a purity check using xrd, small quantities of carbonate (dolomite, siderite, calcite) and amorphous fc-compositions were removed from the m3/2, ro/2, m3/1 and mt fractions with d iluted hydrochloric acid. a method to obtain pure glauconitic material from pul­ verised glauconitic material fractions (aftcr separation in a frantz isodynamic separator) using sedimentation from a water suspension was tested. the fraction < 111m was separated. the purity of glauconitic material from sample m3/2 obtained by this method was much higher than that obtai ned by hand-picking. the glauconit ic material obtained in this way was used in further analy­ sis. olhcr samples purified using the same mcthod gave fractions of equal or less purity than the fractions obtained by hand-picking. fractions m3/1 and m3/2 are equally distributed in scparated glauconitic material of m3 sample. in the m3/1 fraction the grains are mainly subrounded to rounded in shape. in the rg sample about 4/5 of the total glauconitic material content is in the fraction ro/l and about 1/5 in the fraction rg/2. in the mt sample almost all of separated glauconitic material is in the n " 0 0 ~0 ~ 0 i ei0 ii:: ~ :; ~n ,mt 0 a m3/1 jl m3/2 a rg/l a rg/2 ~ ~ 30 20 15 10 5 8/°cuk" fig. 3 xrd powder pallerns of separated g lauconite samples. the indices of diffraction lines of glauconitic material are indicated in lhe pattern of sampl e mt. c = chlorite; m = muscovi te: a = amphibole; q = quartz: p = plagioclase. geologia croatica 5011 mt/l, so only this fraction was analysed as represent­ ing sample mt. depending on the increasing of magnetism the colour of the glauconitic material fraction ranges from light to very dark green. the m3 and mt glauconitic materials have a prominent blue shade whereas the ro fractions have a grass green colour, particularly when pulverised. separated pure or nearly pure glauconitic material fractions (samples mt, m3/1, m3/2, rg/i and rg/2) were analysed chem ically, thermally and by xrd. xrd powder investigations were done on a philips diffractometer, using cuka radiation, a graphite monocromator and proportional counter. diffraction pal terns of randomly oriented air dried samples, and specimens with prefe red orientation (air dried samples and samples treated by ethylene glycol) were recorded. comparing glauconite/smectite and illite/smectite interlayered minerals velde & odin (1975) conclud­ ed that "illite and glauconite mixed layered phases appear to be crystallographically similar." therefore we used the method for ident ification of illitic material by srodon (1984) and srodon & eberl (1984) to identify the glaucon itic material in this study. srodon (1984) used this mcthod for the identification of one glauconite sample (sample no 39 in table 2 of cited paper), too. according to them the ratio for pure illite is determined as follows: ir = 1(001)/1(003) (a ir dried sample) = 1. 1(001 )/1(003) (glycolated sample) if the illitic material is expandable ir will increase, i.e. the ratio increases with increasing amounts of the expandable component. with regard to layer intcrstrati­ fication , the glauconite-smectite series is similar to the illite-smectite series. for th is reason the ir ratio has been used in this paper for comparison of glauconitic materials. the chemical analysis of separated glauconitic material was performed by classical chemical mel hods, while sodium and potassium were determined using a flam e photometer. cation exchange capacity (cec) was determined according to kjejdahl (cit. sus­ tercic, 1969) with previous replaccment of excha­ ngeable cations using ammonium acetate. thermal analyses (dta, tg, dtg) were performed by the mom derivatograph, budapest, with a heating rate of cca 10°c/min. to decrease the influence of rela­ tive moi slure contents, samples were stored in the des­ iccator for 24 hours before analysis. the weight of each sample used in the individual thermal analysis was 0.23 g. the weight loss clue to dehydration was read from tg curvcs according to schultz (i969). 4. results xrd powder patterns of randomly oriented ancl ori­ ented separated glauconitic material are shown in figs. tadcj. slovcncc. l'isljar & lnkret: glauconitic materials from [,ower miocene m<lcelj-sandstolles ... 21 15 10 n "" "" 1x 103 cps 6/°cu k« 5 mt(ao) mt(eg) m3/1 (ad) m3/1(eg) m3/2(ao) m3/2(eg) rg/h ad) rg/2(ao) fig.4 xr d powdcr pa!lerns of oricnted samples. ad air dried sam­ pic: eg ct hylcnc glycol trcatcd sampl e: i'.,.l = muscovite; c = chlorite. 3 and 4, which illustrate tha t samples mt, m3/1, m3/2 and rg/l contain practically no impurities. in contrast, sample rg/2 conta ins numerous im puri ties (chlorite, muscovite, amphibole, quartz, and plagioclase). the same impurities are present in the < 1 !-un fraction of the rg/2 sample, indicating a c lose relationsh ip of glauconitic material and initial substrate of g lauconiti­ za tio n. diffract ion patterns also show that this sample contains the highest quantity of expanding layers. results of chemica l analysis and crystallochemical formula calculated on the basis of olo(oh)l are present­ ed in table 1. the ir-values are presented in table 2. thennoanalyticai curves of separated glauconitic material s are shown in fig. 5. the dta curves display three endothermic effects; the first in the temperature interval from loooe to 200°c which correspond s to dehydration; the second in temperature interval from 450°c to 600°c which corresponds to dehyd roxylisa­ tion, and the third, a weak effect at ~ 900 0 e which indi­ cates di sintegration of structure. according to utsal & utsal ( 1981) a weak exothermic effect at 360380°c may be indicative of the oxidization of structural fe2 +. however, this effect is more obviously expressed in weakly magnetic frac tions, although their feo con­ tents do not di ffe r essentially in wcakly and strong ly magnetic fractions of the relevant samples. for thi s rca­ son it is more probable that the exotherm ic effects men­ tioned above, indicate the presence of impurities that are not detected by xrd. dehydration and dehydroxy li zat ion endothermic effects are accompanied by an eq uival ent weight loss on to curves. besides thc to cu rves the lotal weight losses are also marked in fi g. 5. the weight losses re latcd to ad sorbed and st ru ctural water, whi ch were de termined according to schultz (1969), arc pre­ sented in table 2. s. discussion the alpea nomenclature committee (bailey et ai., 1979; bailey, 1980) have defined glauconit e as an fe-rich dioctah edral mica with tetrahedral ai (or fe3;.) greater than 0.2 atoms pci' formul a unit and octa­ hedral r 3+ correspondingly greater than 1.2 atoms. the interplanar spacing d(060 ) is > i. s i ok addi tional characteristics of glauconite are that the octahed ral charge is greater than +5.3 pci' form ula unit and that the interlayer charge in non-expandablc spcc im ens varies from ~ +0.8 to +0.9 (bailey et ai. , 1984). according to the aipea nomenclature committee the species glauconite is a single-phase and, ideally, is not intc r­ stratified. specimens with expandable layers can be described as randomly interstratified glaucon it e-smec­ tite. buckley et al. (1978) proposed that the term "glauconite" should be used only for those minerals col1laining less tl1an 5% intcrl ayering. according to the samc authors glauconites have mainly the imd typc of structure as indicated by extended basal and reduced hkl reflections 011 thei r xrd powder patterns. struclur­ al imperfcctions of glau conites have previously been attribu ted to in terstralification. the heterogeneity in the composition and structurc of glauconite pell e ts was 22 geologia croalica 50/1 mt m3/1 m3/2 rg/1 rg/2 si02 51 .74 52.14 51.57 50.58 52.94 ti02 0.10 0.15 0.21 0.16 0.26 ai20 3 6.14 11.42 16.44 9.33 10.94 fe20 3 18.98 13.03 8.60 18.46 15.84 feo 4.24 2.17 2.68 2.57 1.97 mgo 3.23 5.17 2.07 3.45 2.21 cao 0.38 0.62 0.59 0.80 1.39 na20 0.29 0.35 0.55 0.41 0.40 kp 8.35 7.81 6.27 7.28 4.88 h20 105 1.51 2.24 5.01 2.90 5.21 loi 5.20 4.85 6.24 4.63 4.45 total 100.1 6 99.96 100.23 100.57 100.49 si 3.79 3.70 3.71 ai 0.21 0.30 0.29 ai 0.32 0.66 1.11 fe3+ 1.05 0.70 0.47 fe2+ 0.26 0.13 0.16 mg 0.35 0.55 0.22 ti 0.01 0.01 0.01 ca 0.03 0.05 0.05 na 0.04 0.05 0.08 k 0.78 0.71 0.58 l (r"r") 1.99 2.05 1.97 l r" 1.37 1.36 1.58 la 0.85 0.81 0.71 used to explain the existence of a series from 1m to imd type structu re (burst, 1958; i-lower, 1961 ; bentor & kastner , 1965). however, sakha­ roy et a l. (1990) demonstrated that homogenous glau­ conites without expandable layers can also give weak and broad ilk! reflections due to thc presencc of struc­ tu ra l dcfects resulting from variolls types of 2:1 layer stacking faults. for this reason, the amount of expand­ ing layers must be also determined in glauconite sam­ ples. numerous authors determined that as the k and fe3+ conte nts dec rease, the amount of al vl increases together with the number of expandable layers (odom,1984). 3.66 3.80 0.34 0.20 0.46 0.72 1.01 0.85 0.16 0.12 0.37 0.24 0.01 0.01 0.06 0.11 0.06 0.06 0.67 0.45 2.01 1.94 1.47 1.57 0.79 0.62 table i chemica l analyses and the number of ions pci' 0lo(oh)2" in the present study the proportions of expandable layers (table 2) have been estimated using the cec values (manghani & hower, 1964) and the k content (thompson & hower, 1975) and by com­ pari son of xrd patterns of glycol-solvated samples with computer calculated diffraction profiles given by thompson & hower (1975) . the est imated pro­ portions of expandable layers are also fairly compatible with the co ntents of adsorbed water and the if-values (table 2). for all samples studied in this paper ir > i (table 2). according to the method of srodon (1984) and srodon & eberl (1984) the plotted 002 and 003 weight losses i % percentage of expandable layers cec kions ir according tg curves from from k from meq/100g per adsorbed structural sample cec' contenf xrd2 o,,(oh), water water mt 0 5 5 7.1 0.78 1.40 1.42 4.68 m3/1 5 >5 5 10.2 0.71 1.61 2.16 4.62 m3/2 12 10-15 10 15.6 0.58 1.93 3.79 4.62 rg/1 < 10 < 10 <10 12.1 0.67 1.87 2.82 4.34 rg/2 35-40 nd 40 31.5 0.45 nd 5.09 4.23 table 2 the contents of expandable layers and corresponding pararnetars for their estimation. legend: i according manghani & hower ( 1964); 2 according thompson & hower (1975): nd not determ ined. tadej. slol'cllec. tisljar 8.: ill l-rel: glauconitic tvtucrials from lowcr miocene milcclj-s:lild~toncs ... 2j mt m311 m3/2 rg/1 rg/2 mt m3/1 m3/2 rg/1 rgi2 100 11){) 300 dta curves tg curves 6.10 6.78 8.41 7.16 9.32 ~oo 500 600 700 1100 900 i/"c fig. 5 thermoanalyticul curves of glauconite silll1ples. weight loss cll rves include corrections from blank curve (althe bollom of fig­ ure). percenl weight losses arc indicated along tg curvcs. re fl ex posi tions of g lyco lated samples re ll in the illit e riel d or vely close 10 it (rig. 2 in srodon, 1984). no samples plotted in the illite/smectite ( lis) field. there­ fo re, acco rdin g to srodon (1984) and srodon & eberl (1 984) all analysed samples (except rg/2) pre­ sent the same type 01" illitic ( in our paper glauconi tic) materia l: mixtures 01" pure illite (respec tively glauco­ nite) and an ish-ordered mineral with < 15% s. 1.6 i.' 1.2 m3/2 1.0 . ~0.8 0.6 0.' 0.2 0.0 +----.-,----,---.---,..----'>,.-,-"--,r­ o 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 fe]" fig. 6 trivalent octahedral ion contents (rj ') per formu la unit. solid lines indicate li mits or glauconi te r) ' content (mod iried from buckley cl ai., 19x4). in rclation to k content , the mt sample is practical­ ly no n-interstratified. sample m3/2 contain s more smec tite layers according to the k con tent and cec value (ta ble 2). it has higher expandability than sug­ gested by the res ult s of srodon (1984) and srodon & eberl ( 1984) method. sa mple mt contai ns only a few ex pandable layers (table 2) and its structural chemica l rofl11uia is very close to the avcragc formula of unaltered glauconites analysed by buckley et a1. (1978). this is confirmed al so by its plot on ihe alv1-fe" di agram (fi g. 6) , as wcll as its position on the diagram which di splays the re lation of d(060) spacings to fe'" ions (fig. 7). the xrd pattern (pig. 3) indicates a imd type s truc ture; however, among all samples analysed in the present study, the mt sample has the less reduced ilkl re fl cc­ tions. all these parameters indicate that the mt sample in fact almost represents single-phase glauconite. samples m3/1 and m3/2 have imd structure (fig. 3). sample m3/1 conlains a little bit more than 5%, and sampl e m3/2 contains 10% to 15% smectiti c layers (table 2). accordi ng to thompson & i-low er ( 1975) both samples show "imil" type or o rdering. the relationsh ip bctween thc number of octahedral ai j .. and fcj .. ions for both samples corresponds to glauconite. samp le m3/2 plot s ve ry ncar to the boundary of the glauconite fi cld (fig. 6). the high alv, content or both samples gives rise to the small d(060) values: 1.5 11 a (m3/l ) ancl 1.510 ii (m3/2) . these values are very close to the celadonite-glaueonite boundary as proposed by buckley ct al. ( 1978), but on the fe)· vs. d(060) diagram, both samplcs plol withi n the glauconite fi e ld (fig. 7). due to the sma ll amo unt 01" expandable layers in sample m3/l, the average chemi ca l co mposition 01" non-ex pandable layers in it is not essentially dirl"erent from the bu lk chemical composi tion presented in table 1. it was not possible to determ ine the average chemical composition of non-expandable layers in sample m3/2, but due to very hi gh al vr content in the bulk sample (table i), il probably corresponds 10 ai-glauconile. 1.51~o 1.5110 0< ~ 1.5150 ~ 1.5ijo 1.5 110 1.5090 m3/2 ++mt rg/1 +rg/2 + m3/1 l-~~ __ ~ __ ~ __ ~_ 0.4 0.6 1.0 1.2 fi g. 7 relationship of d(060) spacing 10 fe)' ions. solid lines indi­ cate approximatc limits of glauconitc (modified from buckley et al. , 19r4). 24 samples m3/l and m3/2 per formula unit con tain 0.66 and 1.11 ai" atoms and 0.55 and 0.22 mg atoms, respective ly (table i ). the large differences in the octahed ral atom content between the two fractions of sample m3 cannot be explai ned either by d ifferences in the amount of expanding layers (l>= 10%), or by differ­ ences in the degree of maturity of glauconite. this dif­ ference in chemical composition indicates e ither differ­ ent initial substrat es of glaucon iti zation, or different ellv ironments of glauconitization. microscopic data ancl diltcrcnccs in the shape and colour or separated grains suggest that detrital glauconitic material is predom inant in the m3/1 fraction whereas the matrix glauconit ic material is predominant in fraction m3/2. rg samp les have essentially different xrd pat­ terns (figs. 3 and 4). the rg/ i sample has imd type of s tructure and co ntains < 10 % expandable layers, and according to thompson & hower (1975) s hows an "imii" type or orde ring. in the octahedral ai 3+_fc3+ ion diagram (fig. 6) ancl in the d(060)-fch diagram (fig. 7), the sample plots in the glauconite fie ld very close to sample mt. the glaucon ite component in thc ro/2 sample eoil­ tains 35-40% expandable layers and, according to 't'hompson & i-[ower ( 1975), represents randomly interstratified glauconite-smectite. chemical compari ­ son between samp les rg/l and rg/2 is not poss ible bec~\l1se sample ro/2 contains impurities and therefore, the chemical com position of smectite is unknown. however, on the basis of opt ical analysis it is presumed that glauconi tic matcrial from samplc rg/ l (predomi­ nant ly in the form of dark-grcen grapy aggregates) and rg/2 (probably other types of glauconitic matri x) rep­ resent different phases of an evolved glauconi te scrics originated from samc or similar initial substrate of glau­ con iti zation. microscopic observations (fig. 2b) and the mincra l composi tion determined by xrd (fig. 3) sug­ gcst th at the g laucon itic material from the ro/2 is a product, at leas t partly, of ch lorite and probably mus­ covite glauconiti za tion . in concordance with odin & matter ( 1981) and odin & fullagar (1988) we identify these stages of g lauconitization for analysed "glauconitic minerals": evolved to highly evolved (mt and m3/l), evolved (rg/ i), s lightly evolved to evolved (m3/2) and sl ightly evolved (rg/2). 6. conclusions the macelj-sandstones were deposited in shallow­ marine environ ment s on forcshores , shorefaces, and tidal flats with or without deltas at stream and small riv­ er mouths . the detrit us load for thc marine shoal s, geologia croarica 5011 which were often separated from the open sea by sandy bars and tidal fla ts, is debris transported by rivers from areas of act ive erosion. periodic but explosive synsedi­ mcntary dac ite-andesite volcanism made possible tuff accumulation (for example, in the area of donje jese­ nje) and the presence of great quantit ies of volcano­ c lastic matcrial within the epiclastie detritus. the vol­ caniclastic material in the detritus was deposited cithcr direct ly during volcanic eruptions, or by it s re-deposi­ tion and acc umulation with the de tritus of the macelj ­ sandstones. data obtained from analysis of 3 samples of the macelj-sandstones show that there arc differences not only among glauconitic material from various locat ions but also among glauconit ic matc rial from the same sandstone sample. these dilterences are already notice­ able from the microscopic examinatio n of sandstones and after glaucon ite separation. 1n the strong ly magne­ tic fractions the glauconitic material has a darker grcen colour than the weakly magnetic fraction and, based on analytical data, thc fomlcr is more evolved. ]n the scrics from highly cvolved to less evolved glauconi tic materi­ a ls, the proportions of expandi ng layers increase from < 5% to approximately 40%. heterogeneity of the m3 sandstone re late s to the magnetic features of glaucon it ic mate rial and the pres­ ence of dctrital glauconitic grai ns po int to redeposition during glauconi tizat ion. significant diltercnces between the chemical composi tion of samples m3/ 1 and m3/2, part icu larly in ai, fe and mg proportions, may suggest differences in the initia l subst rate of glaucon itiza tion from sample m3 as well as differences in comparison wi th glauconitic material from sa mples rg andmt. the de tected mineralogical differences betwcen g lau­ conit ic matcria l from sample m3 are cons istent wi th the microscopic data which indi cates redepos ition of an unconsolidated scdiment. chemical differences of mag­ netically morc homogeneous glauconi tic matcria l from sands tone rg may be expla ined by differcnces in chem ical and stru ctu ral features within the evolving series of glaucon ites which or igi nated in the same glau­ coni ti za tion cycle, from probably the same or si milar initial substrate. in the mt sample only one single mag­ netic frac tion was obtained and thus it can be presumed that the subst rate of glauconitization was unifo rm in composi tion. the results obtained from th is invesli ga tion ne ither deny nor confirm the rcsu lts achieved by other investi­ gators (t[sljar & simunic, 1978; s imun ic et ai., 1990), indicating that glauconitic material from the examined macclj-sandstones were probably produced by alteration of dacite-andesite volcano-clast ic material in shallow-marine environments. tadej. slovcncc. tislj;ir & inkrct: glauconilic maleri;l!.'> from lower miocene macclj-sandsloilcf' ... 25 7. references bailey, s. w. (1980): summary of recommendations of atpea nomenclature commillcc.clay miner., 15,85. ba iley, s.w., brindley, g.w., fanning, d.s. , kodama , h. & martin, r.t. (1984): rcport of the clay minera ls society nomenclature committee for 1982 and 1983.clays clay miner., 32, 239. ba iley , s.w., brindley, g.w., kodama, h. & martin, r.t. (1979): report of the clay minerals society nomenclature committee for 1977 and 1978.clays clay miner., 27,238-239. bentor, y.k. & kastner, m. (1965): notes on the mineralogy and origin of glauconitc.j. sed. petrol., 35,155166. buckley, h.a. , bevan, j.e. , brown, k.m., johnson , l.r. & farmer, v.c. (1978): glau­ con ite and ccladonitc: two se para te mineral spccies.mineral. mag., 42, 373-382. buckley, 1i.a. , easton, a.j. & johnson, l.r. (1984): compositional variations in glauconite.­ mineral. mag. , 48, 1 19126. burst, j.f. ( 1958): mineral hclerogcncity in "glau_ conite" pcllets.amer. mineral., 43, 48 1-497. gorjanov ic-kramberger, d. ( 1904): gcologi­ jska prijcglcdna kana krajj ev inc hrvat skc i siavonije. rogatcc-kozjc (zona 21, col. xiii) 1:75.000 (geo logische ubersiehts-kartc dcs konigsrciches kroaticn-s lavoni cn. rohitsch­ drachcnburg).izd . kr. hrv. slav. dalmal. zcmaljska viacia, odio za ullutarnje poslovc, zagreb. hower, 1. ( 196 1): some raclors concerning the nature and origin of glauconite.amcr. mineral, 46, 313334. mang han i, m. & iiower, 1. (1964): glaucon ites: cation exchange capac ities and infrared spectra.­ amer. mineral., 49, 586-598. odin, g.s. & f'ullagar , p.o. (1988): geological significance of the glaucony facies.in: odin, g.s. (cd.): green marine clays. developmen ts in sedi­ mentology, 45, 295-33 2, elsevier, amsterdam ­ oxford-new york -tokyo. odin, g.s. & matter, a. ( 1981): dc glauconiarum originc.sedimentology, 28, 61 1-641 . odom, e. (1984): glaucon ite and cc ladonite miner­ als.in: micas. reviews in mineralogy , 13 ,545572, m ineral. soc. america. pe'huoi-in, f.j., potter, p.e. & siever, r. ( 1972): sand and sand stones.springer-verlag , ncw york-heidelberg-berlin, 615 p. saki-iarov, b.a., besson, g., drits , va , kameneva , m.yu., salyn, a.l. & smollar, b.b. (1990): x-ray study of the nature of stacking faults in the structure of glauconites.clay mine r. , 25,419-435. schultz, l.g. ( 1969) : lithium and potassiulll absorption, dchydroxylation tcmperature, and struc­ tural water content of aluminous smcct ites. clays clay miner., 17, 115149. srodon, 1. (1984): x-ray powder diffraction identifi ­ cation of illitic matc ria ls.clays clay mine r. , 32, 337-349. srodon, 1. & eberl, d.o. ( 1984) : iiiite.in: micas. reviews in mincralogy, 13, mineral. soc. america. simunic, ai., a vanic, r. & simunic, an. (1990): "macc ljski pjesccnjaci" i vulkanizam znpad llog dijela hrvatskog zagorja (h rvatska).rad lazu , 449, (raz. za prirod. znan., 24), 179194. sustercic, n. (1969): pogonske analize.sko lska knj iga, zagrcb, 221 p. thompson, g.r. & hower, 1. (1975): the miner­ alogy of glauconite.c lay s clay miner. , 23, 289300. t is ljar, 1. & s imu nic , ai. (1978): maceljski pjesccnjaci.vod ic ekskurzijc iii skupa seclimcn­ tologa jugoslavijc, i-irvatsko geol. drustvo, zagreb, 32-37. utsal, k. & utsal, v. (1981): isledovanie izmene­ nia okraski, formi i strukturnih osobcnoslej g laukoni ta estonii pri raznih tcmpcraturah clo 1500°c.tartll ulikooli toimclised, uf. zap. tartlls un-ta, 561, 50-71. velde, b. & odin , o.s. (1975) : further informa­ tions related to the origin or glauconitc. clays clay miner., 23, 376-38 1. manuscript received may 19, 1995. revised manuscript accepted april 28, 1997. 26 geologia croatica 50/1 1. introduction the sava depression represents the most southern part of the pannonian basin (fig. 1). after the middle eocene, a long continental phase started in the area represented by the present depression, during which tectonic movements occurred and a fault network was created along which the basin subsided by extension. the oldest proven sediments belong to the fresh-water ottnangian deposits which are overlain by carpathian, badenian and sarmatian clastic marine sediments. pannonian and pontian sediments were deposited in a brackish to fresh water environment, while pliocene sediments represent fresh water-lacustrine deposits. the thickness of this clastic complex exceeds 4,000 m in the deepest parts of the depression. the complex was interpreted by filjak et al. (1969) as a single sedimentary facies and facies architecture of the ivaniê grad formation (upper pannonian) sava depression, nw croatia boris vrbanac macro-cycle that can be subdivided in three distinct parts. the oldest is composed of coarse clastics (breccias, conglomerates and sandstones), overlain by clays, marls, limestones and biogenic limestones deposited in fresh-water and marine environments with occasional intercalations of effusives. this part of the macro-cycle comprises sediments of ottnangian, badenian and sarmatian age. the middle part of the complex is composed of marls and sandstones that were deposited in a brackish to fresh-water environment, and is of pannonian and pontian age. these sediments represent several turbidite cycles. the final part of the macro-cycle constitutes pliocene and quaternary sediments of a mixed lithological composition sands, gravels, clays and lignite. they were deposited in an alluvial environment, either within the river bed or in the large swamps extending along the rivers, following the elongation of marginal depressions. the studied sediments of the ivaniê grad formation (fig. 2) form part of this clastic complex. the formation contains sandstone bodies in the central parts of the depression, while the marginal and external parts are represented exclusively by massive marls. the upper boundary of the formation in the marginal parts of the depression occurs at a depth of 300-400 m; in the central parts this boundary is below 3,000 m. the total thickness of this formation in the marginal parts is from 150-250 m, while in the central sections it reaches 800 m (fig. 3). part of the sedimentary body composed of turbidite sediments has an elongated narrow fan morphology extending nw-se, 100 km long and 25 km wide. although the exact relationship between the lithostratigraphic and chronostratigraphic units was not determined, the fossil content shows that most of this formation, if not the whole, is upper pannonian in age (fig. 4). the cored material from the central parts of depression, that coincide with the deepest parts of the depositional basin during the late pannonian, is, as a rule, either barren of fossils, or contains fragments of unidentifiable ostracods. in the cores taken from the marginal parts of depression (which were the subsurface uplifts), the upper pannonian sediments are mostly represented by marls occasionally interbedded with thin sandstones. these marls were found to contain fossils. the upper pannonian sediments were also investigated geologia croatica 55/1 57 77 14 figs. zagreb 2002 key words: facies, facies association, areal distribution, turbidites, massive marls, upper pannonian, sava depression, croatia. ina naftaplin, exploration department, ©ubiêeva 29, 10000 zagreb, croatia. e-mail: boris.vrbanac@ina.hr abstract four facies were distinguished within the ivaniê grad formation of the sava depression: massive marl facies (f1), thick-bedded to massive sandstone facies (f2), thin-bedded sandstone facies (f3) and thinbedded sandstone, siltite and marl facies (f4). interpretation of the depositional mechanisms confirmed the presence of two basic sedimentary processes. hemipelagic deposits are represented by finegrained detritus. the lithification of these produced a massive marl (facies f1). sand detritus was transported into the depression by turbidite currents (facies f2f4), and formed a narrow elongated sedimentary body. by comparing the facies defined on the basis of core samples, the spontaneous-potential curve (sp) and the resistivity curve (ra) of identical intervals, four facies associations were defined on well log diagrams: channel filling (fa), depositional lobe (fb), lateral and distal turbidites (fc) and massive marls (fd). 58 geologia croatica 55/1 at outcrop, on mt. medvednica, mt. moslavaëka gora and elsewhere. the presence of macrofossils was also determined. however, no publication describing this upper pannonian fossil fauna, from either outcrops or cores, explains the possible environment habitat of the fauna. it is usually only stated that deposition took place in a protected low-energy environment. over almost the entire area of the sava depression, the ivaniê grad formation overlies the lower pannonian sediments of the prkos formation. only in a narrow strip of dinaridic strike, located in the sw part of depression, does the ivaniê grad formation directly overlie the badenian sediments. the lithological composition of the prkos formation is mainly of shallowwater thin or thick-layered marls, calcareous marls and marly limestones. sandstones are only rarely found in the form of millimetre-thick layers or laminae. the lower/upper pannonian contact has not been precisely defined, but it can be concluded that it roughly corresponds with the contact between the lithostratigraphic units. the prkos formation is relatively easily identified on the well logs, but its age is rarely palaeontologically documented, due to the very scarce fossil content of the cores. nevertheless, the cored material of the prkos formation contains a lower pannonian fauna without exception, while the cores taken from the overlying ivaniê grad formation mostly contain an upper pannonian fauna, if any. similarly, the sediments of the kloπtar ivaniê formation, overlying the ivaniê grad formation over the entire exploration area, exclusively contain a lower pontian fauna. the kloπtar ivaniê formation bears lithological and depositional similarities with the ivaniê grad formation which means that such lithostratigraphic subdivision was conditioned by the practical, petroleum-geological reasons. two basic concepts have been postulated to explain the depositional environment of these sediments. according to pletikapi∆ (1965) the water depth was shallow, and the cyclic character of the sediments was due to frequent moving of the shore line and a high energy area. only in limited area and the constant subsidence of blocks along active tectonic lines, could the water depth have increased significantly in very narrow channels where turbidite currents could have developed. according to milju© & vugrinec (1977) the ivaniê grad formation was deposited during a regressive phase. in zones of shallow water coasts pelites were mostly deposited, while sandstones were deposited in the places of higher energy such as channels. lu»i∆ (1994) interpreted the facies as coastal sediments, bar and beach sediments, interbar shoals, lagoon sediments and tidal channel sediments of coastal plains. the results of palynological analyses are contained in an unpublished work (lu»i∆ & krizmani∆, 19931). the established palyno flora is composed of environmentally different phytoplankton fossils. the genus s p i n i f e r i t e s is very common and is characteristic of shallow environments. alternatively, impaginidium and g o n y a u l a x are phytoplankton that lived in deep water. despite the possibility that such an association can be interpreted in terms of the deep water environment wherein the shallow water organisms were transported by resedimentation, the authors express the opinion (after sütö-szentai, 1982) that this was the case of a shallow environment with occasional transport of the deep water organisms by the sea currents, which means that they were mixed with other fossils in the littoral zone. there are significant differences in the age determination between the palynological analyses of the core material from the three major oil fields ivaniê, æutica and okoli. these results remained unpublished in professional studies within the department of the central laboratory. the samples from the ivaniê grad formation were found to pertain the lower and upper pontian, and upper pannonian. it has to be noted that not a single sample with palynological findings has also been documented by macrofossils. dali∆ (1996) singled out five different lithofacies offshore homogeneous marl deposits; well sorted marl intercalated with siltstones and marl deposited as progradational shoreface and/or as barrier bar; marl with coal laminae and lithoarenite layers deposited on tidal flat in estuaries; marl intercalated with siltstone and fine grained sandstones were interpreted as shallow shelf deposits with lagoonal characteristics; well sorted lithoarenites as a subtidal barrier bar. ©imon (1980) believed, on the basis of the geometry and lithological properties, that these sediments belong to “the family of redeposited coarse clastics”. he applied the concept of “submarine-sublacustrine fan” to explain deposition. in defining the depositional environment of the okoli sandstones (the youngest fig. 1 location map of the sava depression. 1 lu»i∆, d. & krizmani∆, k. (1993): zavrπno izvjeπêe, buπotina okoli-57, biostratigrafska, litofacijesna i sedimentoloπka interpretacija.unpubl. report, ina-naftaplin archive, zagreb. member of the ivaniê grad formation), in part of the æutica oil field, vrbanac (1989, 1990) believed that they belonged to the channelised part of a submarine fan (to its middle proximal part). the detritus was carried by gravitational flows which could be compared to turbidity flows. in his later work vrbanac (1996) reconstructed a palaeogeographic view of the sava depression during the upper pannonian, and concluded that it was a marked sub-sea (sub-lake) palaeorelief, the major feature of which was a central tectonic graben surrounded by submarine highs the medvednica horst in the ne, moslavaëka gora horst in the north, martinska ves horst in the south, and the psunj-prosara ridge in the east (fig. 2). the bottom of this graben was irregular and mildly inclined in a se-e direction, with some occasional steepening. he also concluded that this was a calm, low-energy environment, with a sedimentary basin large and deep enough to ensure a stable depositional environment, to compensate for the variations of the factors that respectively influence depositional mechanisms in a tectonically active basin.the source area of the clastic material was n-nw from the area named the “alps mineral association”, and it can be concluded that there was lengthy transport of the probably extensively resedimented material (©∆avni»ar, 1979). although they did not directly study the areas of the drava and sava depressions, hungarian authors also think that during the pannonian (pannonian s.s.) a deep water system existed with early turbidites, and later 59vrbanac: facies and facies architecture of the ivaniê grad formation... fig. 2 location map of the explored area. 60 geologia croatica 55/1 delta slope sediments (mattick et al., 1985, 1988; szentgyörgyi & juhász, 1988; clayton & koncz, 1994; hámor & bérczi, 1999). 2. sedimentological analyses of core samples detailed sedimentological analysis, layer-by-layer, was carried out on the cores from 29 wells distributed throughout the sava depression. the 61 cored intervals were analysed with a total length of 569 m that covers almost the entire interval of the studied formation. the cores are mostly in isolated intervals that are not more than 6 m length. only 6 wells were found to have continuous coring ranging from 27-82.1 m in length. since most of the cores were taken 20 or more years ago, lots of the core material was either missing or was found fragmented in irregular small pieces that were unsuitable for sedimentological analysis. 2.1. petrography sandstone, siltite and marl alternate with each other. data on the petrographic, mineralogical and physical properties of the sediments are provided by experts from ina-naftaplin’s central laboratory. sandstones are present only in the central part of the depression, pinching out towards the edges. they are grey (mostly light grey) in colour, only those saturated with oil are brown. sandstone bedding is well expressed in parts where they are interbedded with marl; bed thickness may reach several metres. they belong to a group of very fine to fine-grained sands with average grain size of 0.08-0.2 mm, rarely medium grained (≤0.5mm). roundness varies between 0.2-0.3, belonging to the group of subangular grains. sphericity grade values are balanced and vary between 0.68-0.74, making them highly spherical particles. sandstone porosity is 10-33%, with significant differences in these values regarding the regional spatial fig. 3 isopach map of the ivaniê grad formation. 61vrbanac: facies and facies architecture of the ivaniê grad formation... distribution of sandstones in relation to the source area of the detrital material and different facies. parallel presentation data of porosity on several oil fields (bokor et al., 1979) show a distinct decrease of these values from northwest to southeast. great differences in porosity and permeability values are also statistically proven in ivaniê grad sandstones which belong to different facies. maximum values are determined in the distributory channel sandstones, while sandstones of levees and lobes have considerably lower values (–urekovi∆, 1995). the petrographic uniformity of the upper pannonian sandstones has long been noted (©∆avni»ar, 1979). quartz is the main component, together with rock fragments, micas and feldspars. quartz does not exceed 60% of the detritus. among rock fragments (1835% of composition), the most dominant are limestone and dolomite, while grains of cherts, quartzite, clay shale, chloritic and sericite shales, quartz-muscovitic shale and gneiss, with rare fragments of granite and tuff are also present. the clay mineral content is very low (<5%, mostly 1-2%). cement is formed by a mixture of prevailing calcite and detritic silt-clayey matrix. the detrital matrix contains illite, kaolinite, quartz, chlorite, plagioclase and mica. sandstone cementation is not always complete, so many sandstone beds are poorly cemented and friable. according to their composition, they are litharenites, respectively calclithoarenites since in rock cuttings carbonate sediments are dominant2. relatively large quantities of unstable grains indicate the low maturity of sandstones (©∆avni»ar, 1979). the best indicator of the petrographic uniformity of this formation is the identical composition of accessory heavy minerals, with the dominance of chlorite and garnet and to a lesser extent biotite, staurolite, disthene, epidote, zoisite, apatite, tourmaline, zircon and rutile. such an association of heavy minerals indicates that the source areas of the detritic material were probably the alps with metamorphic rocks of epi and mezzo zones, as well as with limestones and cherts (©∆avni»ar, 1979). a great number of sandstone beds contain dark grey marl clasts. clasts are mostly of an irregular and subangular shape. their dimensions vary considerably; more often to 1-2 cm, very rare to 10 cm. they are found either dispersed, scattared in great numbers, or massively. they can be scattered irregularly but mostly appear so that their longer axis is parallel or subparallel to the bedding plane. they are mostly found in the lower parts of sandstone beds, although they can also be present in the central and upper parts. the mineralogical composition of siltites is identical to that of the sandstones except for a higher mica content. flat and/or cross-lamination is almost always present, and visible due to presence of organic matter or mica. burrows of ichnofossils are frequently noticed, as well as tiny marl clasts. siltite porosity is mostly below 5%; permeability is also very poor, less then 10 µm2x10-3. marls are grey brown, brown, dark grey and often almost black in colour. they are mostly hard, fissile and show parallel bedding planes where numerous carbonised plant remnants are frequently obseved. these remnants are mostly particle-sized but can be larger than 10 cm. bioturbation is sporadically strongly fig. 4 correlation table of the chronostratigraphic and lithostratigraphic units and position of the ek markers. 62 geologia croatica 55/1 expressed. ichnofossils look like winding tubes filled with sand or marl material. petrographic analyses show that the marls consist of a clay-carbonate and cryptocrystal base with more or less fine grained quartz and mica of silt or sand dimensions. the caco3 content is about 60%. 2.2. facies according to the sedimentological properties of the cored deposits (lithology, bedding, texture, relation between lithological members) four facies were identified: massive marl facies (f1), thick bedded to massive sandstone facies (f2), thin bedded sandstone facies (f3), and laminated sandstone, siltite and marl facies (f4) 2.2.1. massive marl facies (f1) this facies consists of homogenous and massive, mostly unbedded marls, dark grey to almost black in colour (fig. 5a). sporadically preserved signs of bedding and lamination are mainly expressed by a colour change, and occasionally by thin siltite or sandstone laminae or beds. the massive homogenous appearance is sporadically disturbed by burrows, but those traces of organism activities did not disturb rare primary internal structure and textural properties. massive marls are the “normal” basin deposit, as hemipelagic muds which covered the basin floor relief under stable conditions. the uniform petrographic structure of detritical material indicates material transported by turbidity currents, but the transport mechanism and mode of deposition is different. thickness of massive marls in the marginal, morphologically higher parts of the depression, reaches 150-250 m, and up to 250 m in the central lower parts. thin siltite and sandstone intercalations and laminae in the massive marl are of turbidite origin, reflecting the enlargement of turbidity flow area in the direction of movement as well as in their lateral spreading. 2.2.2. thick bedded to massive sandstone facies (f2) this facies is represented by thick-bedded to massive homogenous sandstones with a few siltite and marl intercalations which can be compared to massive sandstone facies (walker, 1978). the thickness of individual sandstone beds from the cored intervals is from 0.5-6 m (fig. 5b). amalgamation is frequently present. it is expressed by sharp changes in colour nuance within homogenous sandstone beds, or by sharp changes in grain size of sandstones. frequently, several metre long intervals of sandstone cores were broken into pieces only a few cm long or even smaller, making sedimentological analysis impossible. it is debatable whether these significant thicknesses of sandstone beds could be the consequence of amalgamation which, due to the identical content and physical properties of sand detritus, and broken of cores, can not always be determined. this facies appears exclusively within distributory channels where the energy of turbidity flows was the highest and where the effects of erosion on the base by mud flows were most strongly expressed. lower bedding planes are sharp and with more or less expressed traces of erosion. sandstones of this facies can be of different structure. a lot of beds are massive and homogenous. normal gradation can be noticed only in a few beds, in their upper part, while it is less frequent in their lowest part or within the bed. even though there is usually no gradual transition between a sandstone bed and overlying marl, some sandstones gradually grade into siltite and marl. in such beds horizontal and lateral siltite lamination can be noticed, as well as convolution. the thickness of these seal marls does not exceed several centimetres. less commonly there are cases of inverse gradation. lamination is very seldom present. frequently, horizontal or wavy lamination within sandstones which are abruptly cut off on the upper side by a massive sandstone with no texture, points to amalgamation, during which the upper laminated part was carried away, probably together with the capping marl. deformed bedding and lamination, and convolute bedding or lamination is common. this is the result of hydroplastic deformation of unconsolidated deposits over which strong water flows passed during sedimentation (sanders, 1965), as well as in the post-sedimentation phase as the result of the sudden displacement of pore water (lowe, 1975). in this way dish structures and sand dikes are formed. frequently, flame structures occur on the lower surface of sandstone layers, and it could be established for some clasts that they were formed by the breaking of thin marl beds due to the sudden displacement of pore water, and their “intrusion” into overlying sandstone or even siltite beds. some deformations are probably the result of sliding of poorly compacted material down the slope. due to expressed lamination, sinsedimentary faults of small dimensions are often noticed, both normal and reverse. on lower bedding surface visible traces were left by erosion of the flow itself and/or traces of erosion by objects moving over the bottom: clasts, plant parts etc. marl clasts of different dimensions and different roundness grades and carbonised plant remnants are quite common. while carbonised plant remnants of different dimensions originate from continental regions, marl clasts were formed by the erosion of poorly consolidated sediments of the channel flanks and bottom, started by turbidity flows. the estimated proportion of marl and siltite in this facies does not exceed 10%. the internal bed constitution and textural properties are mostly the result of the final stage of transport and 2 physical and petrographic data department of central laboratory ina-naftaplin. 6 3 v rb a n a c: f a cie s a n d f a cie s a rch ite ctu re o f th e iva n iê g ra d f o rm a tio n ... f ig . 5 l ith o lo g ic co lu m n s. .. ) 21$1 in 21s6 m oks7 'i:~!r_· i ,~:.., ;'-',' ii 1 ~'=-co-;;:, 1 ;:.:,i.';:; ;.d·~~~j ;~l~:~ n~f~ 1 ~:fut-~, tt~~-:.;:-·: ~;r~ j ~-;=~ ~ ~'~~t ';...i ·~~ l-;~:~' j ·~·~ii.~~: bj-j b) 26) 1m "'i"',,-'-~"ti--"" 2616 m ~~ h ~) 1200.9 m 1203.!f m legend lilh"'dkji gi-j1 c:j _dlrro •• o sillite k clj marl t""~r~ r;. u ~ carboni.cd plallr. renmanls bioturbation boru<mtsl laminotio. und."" homowiilaminatiqd _ lare",l lamiruition ~ -~ marl dagb; amalgamalion 011 convolution j d) 1612.6 m 16n6m iv.·is 64 geologia croatica 55/1 deposition (postma, 1986), and are of special importance for the interpretation of environment and deposition conditions. thick sandstone beds which are massive in their major part, and show a decrease in grain size (gradation) in their top part, grading into thin, horizontally laminated, and cross-laminated sandstone or siltite covered by thin marl, could be compared to bouma sequence of ta-e type (bouma, 1962). the high quantity of sand (thick beds) indicates the extremely high energy and capacity of these flows. the presence of marl clasts in different parts of the bed and the erosional base of the bed also suggests turbulent flow. according to the above characteristics, they can be compared with turbidites deposited from mud flows of high concentration, where the detritus population i and ii (lowe, 1982) was supported by upward turbulence (middleton, 1970; lowe, 1979, 1982). in the flow base where slipping was the most intensive, it was probably supported by dispersive pressure (midlleton, 1967; lowe, 1976, 1982). namely, sediments deposited from liquid flows have flat bases due to their laminar character and high density of flows (lowe, 1982), so these type of flows are not taken into account. sedimentation occurred by direct, rapid and massive suspension sedimentation (walker, 1978), until the bedding plane did not reach the top of the turbidite current cloud. the energy of such flows was 5 wm-2 (allen, 1984). deposits formed by direct suspension sedimentation belong to poorly packed sedi ments (kolbuszewski, 1950). these deposits are poorly cohesive and strongly subject to liquefaction and forming of secondary water escape pipes (lowe & lopiccolo, 1974; lowe, 1975). it is considered (lowe, 1982) that at this development stage of mud flows, a suspension mass of high density can almost momentarily form an ta interval bouma sequence several metres thick without any traction sedimentation textures. 2.2.3. thin-bedded sandstone facies (f3) this facies is represented by sandstone beds several centimeters to 0.5m thick (fig. 5c). the proportion of marl and siltite in this facies is 30-40%. regarding internal structure and gradation, the interval with horizontal and lateral sandstone and siltite lamination, and horizontal lamination in fine grained material is the most frequent. bouma sequences of type ta-e, tb-e and tc-e are all common. some of these beds are parallel laminated throughout their entire thickness, while in their upper part they pass relatively suddenly into siltite and marl. this facies can be found as the final beds in the sediment sequence deposited in distribution channels, but are more characteristic as marginal channel sediments. the basal boundary is sharp, and very often strong or weak erosion traces can be noticed on the upper bedding plane of the underlying marl. amalgamation was not noticed or at least is not characteristic for sandstones of this facies. convolution is very often present in all parts of the bed, as well as dish structures. small marl clasts (<5 cm) are quite frequent, and are also found in all parts of the sandstone bed. the thickness of marl which appears among the sandstones varies from several to tens centimetres. marl bioturbation is well expressed, especially in thicker intercalations. the marl/siltite ratio is significantly higher in this facies, and the estimated value is 30-40%. this facies consists of repeated sandstone and marl beds. sharp lower bedding planes of the overlying sandstone and the gradual upward passage into marl, confirm spasmodic turbidite currents which, compared with flows of the previous facies, are more diluted. on the basis of their internal textures and their constant succession, or similarity of these beds to a bouma sequence, they can be interpreted as turbidites, with a lower proximity index than the previous facies, due to a significantly lower proportion of the ta interval. 2.2.4. thin bedded sandstone, siltite and marl facies (f4) facies four consists of very thin, thin -medium thick sandstone beds in monotonous alternation, passing upwards into siltite and marl, or there are thin siltite intercalations that grade upward into marl (fig. 5d) they are mostly several centimetre thick beds that start with a sharp bedding plane. on the upper bedding plane of the marl, traces of weak erosion of the subsequently developed mud flow are sometimes visible. internal textures are represented by horizontal and cross lamination, convolution, and structures developed by water displacement sand dykes. there is a rare occurrence of uplifted beds, and deformed beds. ta-e and tb-e type sequences occur being less numerous than tc-e and td-e sequences. beds of this facies are characteristic for the marginal parts of the channel or prominent parts of the bottom relief where the energy and influence of turbidity currents in the depositional processes were distinctly weaker. marl clasts of 2 cm size are also present, as well as carbonised plant remnants. in smaller sediment fractions ichnofossils occur regularly, and are sporadically visible in the coarser fractions. the traces of digging, drilling and moving of organisms in the sediment are occasionally so abundant that they disturb primary textures. the proportion of marl and siltite in this facies is estimated as between 50-60%. thin beds of well laminated fine-grained sandstone and siltite in alternation with marl, frequently organised in bouma sequence tc-e, suggest that at least a part of these beds were formed by deposition from turbidity currents of low concentration. in this regard, this facies corresponds to thin bedded low energy levee deposits (mutti & ricci-lucci, 1975; walker, 1978) or distal turbidite deposits. 65vrbanac: facies and facies architecture of the ivaniê grad formation... 3. origin of detrital material the deposits are interpreted as sediments of moderate water depth. detrital material was brought into the basin by turbidity flows or as normal basin deposit. the constant sandstone type, uniform detrital content, consistent structural characteristics and composition of heavy minerals suggest alpine metamorphics as the source rocks. however, a significant part of the carbonate detritus in the content of sandstone, as well as the carbonate-clay content of siltite and marl and plant remnants in marls, indicate more local sources of detrital material. it can be assumed that the detrital material has been reworked several times, the basis of which is formed from an association of metamorphic minerals and fragments of metamorphites of alpine origin, enriched with carbonate and clay material from local sources. the concept of the depositional environment of the study area suggests that the present sava depression was part of the southern marginal part of the pannonian basin (lake) which extended southwards probably significantly further from the presently determined boundaries. prior to deposition in the sava depression, the detrital material was, after other probable multiple episodes of deposition, deposited into the area of todays mura depresion, which represented a slope area area of material accumulation, from where it was occasionally carried into the sava depression. coarse material was brought by turbidity flows while pelitic material was continuously brought and deposited by aggradation in the basin regardless of its morphology. since turbidity flows moved through the deepest parts of the basin, a substantial mass of sand detritus was deposited in the deepest parts of the basin. 4. facies association according to sp and ra curves sp and gamma-ray curves reflect the change in grain size in clastic sediments. this is why they are used for the identification of lithologic structure/composition and boundaries between formations, as well as for the identification of depositional environments (e.g. galloway, 1968, 1998; fisher, 1969; pirson, 1970; selley, 1976, 1985). the sp curve is the basic curve which defines facies associations of the studied layers containing sandstones (turbidite facies associations), while ra curve determines the massive marl facies association. the sp curve has values that are a function of the grain size of sand detritus, and the relationship can be established between the funnel or bell shape of these curves and the tendency to coarsen or fine upward. with regard to the sedimentological analyses which showed the structural complexity of sedimentary bodies built of thin intercalations of sandstone and marl, it can be determined that the thickness ratio in sandstone and marl intercalations in alternation have a crucial influence on the final shape of sp curve. a comparison of the sp curve and a lithologic column of the same interval in gl-31 well (fig. 6), shows that sp values depend on the relationship between thicknesses of sandstone and marl intercalafig. 6 comparison between lithologic column and corresponding interval on the sp curve. 66 geologia croatica 55/1 tions. granulometric analyses performed on sandstone intercalations indicate approximately identical values of average grain diameter (md). a tendency of upward coarsening of sandstone beds on the sp curve is expressed by a funnel curve shape. this symmetry/regularity was established in numerous examples of upward coarsening of sandstone beds. a tendency of upward fining of sandstone beds, noticed in cores, results in a bell shape sp curve. taking into consideration the facies that were determined by sedimentological analyses (f1-f4), and the defined depositional environment (©imon, 1980; vrbanac, 1989, 1996), as well as the sp and ra curve shapes, four associations of facies were singled out: channel filling facies association (fa), depositional lobe facies association (fb), lateral or distal turbidites facies association (fc), and massive marls facies association (fd). facies associations were recognized and defined on well log diagrams (sp and ra curves), which enabled the reconstruction of their structure in space, and mutual relationship. since that relationship can be best observed in oil fields owing to a great number of wells on a relatively small area, the æutica oil field was selected, where relationships of facies associations were shown in detail, as an illustration of relationships in the depression. 4.1. channel filling facies association (f a) this facies association consists of thick-bedded sandstone facies (f2) and thin-bedded sandstone facies (f3) . the channel axis is characterised by thick sandstone beds with sporadic marl intercalations. sandstone beds become thinner towards the channel edges, while marl intercalations become thicker. it is important to emphasise that the expression “channel” does not imply the type of channel which is forming within a classic fan that occurred in the continental slope towards the open sea. the depositional sequence of channel sediments is represented on the sp curve by a bell shaped or cylindrical curve (pirson, 1970; syed, 1979; galloway, 1998). the thickness of some depositional sequences is 10-20 m; most frequently, several sequences are joined into one sandstone body (fig. 7). a depositional sequence is formed of sandstone beds which are characterised by a certain shape on the sp curve bell, funnel or cylindrical shape. these shapes reflect the tendency of the changing thickness of sandstone and marl beds in alternation. one depositional sequence can be formed by one sandstone bed or there can be several depositional sequences separated by rather thick marl intercalations. trends of particular sequences may or may not correspond. bed erosion is strongest in the middle parts of the channel, and weaker in the marginal parts, so that the absence of marl intercalations, and numerous amalgamations undoubtedly suggest the position of the channel axis, or direction of the main flow of the turbidity current in some phases of detrital deposition. so, channels were both depositional (hamilton, 1967) and erosional (laughton, 1968). the main mass of turbidity current passed through these channels. as turbidity current energy weakened, particles carried in suspension were deposited. therefore, the thickest sandstone beds are related to the channels whose position, in the deepest parts of the basin, depended on basin morphology which was controlled by synsedimentary tectonics. the channel width for the member of iva sandstones on the æutica oil field is about 250 m, possibly up to 1000 m. some channels have a constant width; others split into two arms or two channels merge into one. the channel was probably not very deep, except where the association of facies fa is laterally equivalent to the association of facies fc or even fd, it probably concerned a deeper channel of steep flanks which had a narrow or non depositional area for facies associations fb or even fc. turbidity currents ran mostly through the channel itself. outside the channel only the marginal parts of the turbidite cloud carried detritus depositing associations of facies fb and fc. on the sp curve diagram of the iva-15 well (fig. 7), the channel filling facies association fa is expressed as a succession of depositional sequences with a tendency of upward fining of sandstone beds, composed of f2 and f3 facies sandstones. they were amalgamated by stronger or weaker erosion into some 80 m thick sandstone bodies. on the sp curve, the association of channel sandstone facies is shown as a funnel shape, as the result of the abrupt formation of a channel and deposition of thick sandstone beds. in the final phase, upward fining sandstones and marls were deposited, depending on the migration speed of the channel. if the migration was abrupt, sp curve is of cylindric shape. although there was no statistical research of the relationship between sandstone and marl within this facies association, sandstone probably forms 90% of the total. 4.2. depositional lobe facies association (f b) this association is composed of f3 facies in the lower part and facies f2 in its upper part. they were deposited outside and parallel to the distributary channels where the power of turbidite currents is significantly weaker so that erosional occurences, if any, are less expressed than within the channel. as a consequence, amalgamation is very rare. the total thickness of sandstone bodies that belong to this facies association can exceed 30 m. sandstone beds of this association show a tendency to coarsen upward, while marl intercalations are usually ten centimetres thick and more. on the sp curve diagram of the iva-15 well (fig. 7), the fb association of facies is expressed as a depositional sequence of upward coarsening sandstone beds, and 67vrbanac: facies and facies architecture of the ivaniê grad formation... by a funnel shaped curve. the depositional environment of this association of facies is parallel to channel extension, it directly continues on channels and extends for several to tens of kilometres in length and several hundred metres to 1-2 km in width. in its narrowest part this zone is less than several tens of meters wide. this facies association is characteristic for a near channel zone, or marginal parts of the channel, since turbidite currents of great capacity did not move only through channels but also in a wider channel zone. in this way, from time to time, thick sandstone beds were deposited outside the channel. the estimated proportion of sandstone is 70 to 80%. 4.3. lateral or distal turbidite facies association (f c) this association consists of a monotonous alternation of very thin, thin and medium thick sandstone beds (according to campbell, 1967) passing into siltites and marls. they are represented by facies f3 and f2. on upper bedding surfaces there is practically no erosion or only very weak traces can be noticed. alternation of thin marl and sandstone intercalations cannot be registered by the logging tools, making the derived sp curve a result of the relationships between final lithological members (fig. 7). this association of facies is characfig. 7 vertical succession of the facies associations. 68 geologia croatica 55/1 teristic for the areas of distal and lateral termination extend of the turbidite currents, as well as the morphologically higher interchannel areas. in a lateral direction further from the channel, namely from the area of deposition of channel sandstones, the share of sandstone decreases with increasing share of siltite and marl. this decrease of turbidite bed thickness continues until they pinch out. the total bed thickness of this facies association may be several tens of metres. in the north west and central part of the depression, areas of turbidite occurrences have a narrow elongated shape several hundred metres wide, roughly following the channel direction. they were formed by deposition of sandstone and fine grained detritus in the lateral, transitional parts of the basin, between the main current area and morphologically higher zones. therefore, deposition took place in the area where the turbidite current travelled, but were affected only by the upper part of the turbidite cloud which is, in this part, thin and of low energy, and capable of carrying only small quantities of sand. distal turbidites correspond to classic turbidites being deposited at the end of the basin plain, namely in the area of termination of the turbidite current (walker, 1978). the estimated sandstone ratio in the deposits of this facies association is between 30 and 50%. 4.4. massive marls facies association (f d) this association is mostly represented by massive marl facies f1 with rare intercalations of thin siltite or sandstone laminae or beds (fig. 7). the depositional environment of this facies association is the whole area of the sava depression; only in its central parts is this association “masked” by turbidite associations. in the lateral, morphologically higher parts of the basin, sediments of this association were exclusively deposited, while in the central, morphologically deepest parts of the basin, they only form a part of the depositional sequence. 5. facies associations architecture depositional architecture in a basin reflects the interaction of processes of sediment supply, relative subsidence or uplifting and eustatic changes of sea level (galloway, 1998). in addition, an important role in depositional evolution are local factors: water depth in the basin, palaeorelief, palaeoclimate, transport and depositional mechanisms, quantity of transported detritus and current velocity, local synsedimentary movements, etc. the influence of each factor can significantly vary in different parts of the basin, which additionally makes the determination of relationships between lithological members and facies in the basin more difficult. 5.1. lateral changes of facies associations determination of facies associations on well logs, more particulary on sp and ra curves, is especially reliable in oil fields with many wells in a relatively small area. by following lateral relationships on the favourably positioned profiles, perpendicular to the strike of distributary channels, the facies association of channel filling is most frequently well noticed, as is their lateral transition into the depositional lobe facies association and facies association of lateral turbidites, while beyond the direction of turbidite currents the massive marls facies association was deposited. lateral spreading of the channel filling facies association depends on the width of the basin bottom and slope of the channel. there are examples in the æutica oil field where the facies association of a several tens metres thick channel filling is laterally continuous into a narrow zone of thin (∼10 m) lateral turbidites facies association. this zone is followed by the massive marl facies association (2-5 m thick, fig. 8). the association of massive marl facies appears in all parts of the depression that were outside the turbidite current direction, or in parts of the depression that are so far above the channel bottom that turbidite currents could not or seldom reached them. the morphologically higher parts of the bottom were also found in the central part of the depression, so that the facies association of massive marl was often surrounded by the association of facies containing sandstones (figs. 10 and 12). in observing the lateral succession of facies associations, a general rule for their distribution is noticed. parallel with the spreading of channels in which the channel filling facies association was deposited, the lobe facies association most frequently appears, followed by the association of lateral turbidite facies which pass laterally into the association of massive marl facies (fig. 8). this distribution of the facies associations follows a general rule of the distribution of facies in a fan (walker, 1978). central deposition occurs in the channels where thick-bedded to massive sandstones were deposited. in near channel zones, thin and thick bedded sandstones were deposited, while in a more distal turbidite current direction, and lateral to the channel axis, thin bedded turbidite sandstones and massive marls were deposited (fig. 9). detailed distributional relationships between the facies associations is shown in the example of a sandstone body member of the iva sandstones of the æutica oil field. in this field a member contains ten sandstone bodies. the lowest is γ8, followed by γ7, γ6, γ5, γ4, γ3, γ2, γx, γ1 and γ0. maps are given for γ4, γ3, γ2 and γ1. on the maps, for each sandstone body, distributional channel areas were marked where the deposited channel filling facies associations (fa), other facies associations (fbfc), and the massive marl facies association (figs. 1013) were deposited. on the maps, the form of the channel system, changes of channel position in space, and changes in the shape and size of deposition surfaces of sandstone detritus are easily observed. within distribu69vrbanac: facies and facies architecture of the ivaniê grad formation... fig. 8 correlation profile over the sw section of æutica oil field. , i --1s:llh:oj.9mtws 1'10jlo _ ........ , --i fi'.i ~ "iii a "0 q ti ; ~ "8 "" ~ ra -,... u ~ 1 d'3 rn u i1il ~ -e , ~ ~ ~ ~ jli ~~ ---+----~. ~~----,_--~!--~~~-r--­ ! ! 0 70 geologia croatica 55/1 fig. 9 facies associations distribution upper part of iva sandstone. tary channels there are clearly marked areas where, due to the erosional action of turbidite currents, a direct contact between two or more sandstone bodies occurred. the existence of three hydrodynamic units which were determined during oil and gas exploitation explain the erosional action of turbidity currents. the sandstone bodies γ8, γ7 and γ6 form one hydrodynamic unit, γ5, γ4, γ3 and γ2 form the second, and γx, γ1 and γ0 form the third, and it is obvious that the erosional action of turbidite currents, which brought certain sandstone bodies into direct contact, directly influenced the establishment of the hydrodynamic relationships. 5.2. vertical succession of facies association most interpretations of depositional sequences are based on facies sequence, namely on observation of facies of the progradational and retrogradational movements of lobes and channel filling (mutti & ghibaudo, 1972). let us consider the vertical rela71vrbanac: facies and facies architecture of the ivaniê grad formation... tionships of the facies associations of the whole ivaniê grad formation. the example of the iva-15 well (fig. 7) clearly illustrates the vertical succession of the facies associations of the iva-sandstone member that appear over the whole area of the depression. the sequence begins with the massive marls facies association as basinal hemipelagics, followed by the facies association of lateral (distal) turbidites represented by a serrated sp curve. it is further followed by the depositional lobe facies association (prograding lobe), which is obvious fig. 10 distribution map of γ4 sandstone body (iva sandstone) in æutica oil field. ~ • ~ • ~, • distribtmon map of "(. sandstone oody in tl,rnca oil field .... -1;" 1,,-73 ... ,1 pin<ll 0"' lim of sanditont _ fa • <b."".1 filii".: {xi .. ow>ciatioll _ fb · ikpooilionallob< f.d", u>ociariou _ fe· iaiem io>d di.lal _dii< ~,_ '_"'0' i i'd • __ i"" tnar1 fo<;os __ _ act""", or <"""'01 j)"i<mj (<if1 y.'1"~) ~" • 1 ... )' i'»-'o' • • ~. ~ • , .. ,. "'"'" z..111 • • 1.0-.. , • 72 geologia croatica 55/1 by the tendency of upward thickening sandstone beds (funnel shape of sp curve), and the channel filling facies association marked by a bell shaped sp curve. the depositional lobe facies association is repeated marking side channel migration, followed by distal turbidity facies association, and massive marl facies association. the vertical succession of facies associations can be well observed on the profile which shows the section through the ivaniê grad formation of the æutica oil fig. 11 distribution map of γ3 sandstone body (iva sandstone) in æutica oil field. ~ . • r..", • • t..-ill • ~ • ~ • dlstrlbtrrlon mal' or y, sandsto.ne body in 2utica oil field pid<ho\ltull< 0(_ _ fa • <h""",1 fillh •• ""in oho<\afun _ po _ deposi. ioo&liobe facies oosoc\afun _ fc _ ~i odd distal turbidite foci .. ossociaiioo fd ...... iv. mart focies_iatioo ::~r ",ntoc'aftaofchanncl 'l"'=' (2i!l ptyj'1'+y» ~"' • ~­• ~, . • ~ . • t..jf, • ~, • 73vrbanac: facies and facies architecture of the ivaniê grad formation... field (fig. 8). not only is the vertical succession of associations in each well obvious, but also the lateral transitions of one facies association into the other, from the channel filling facies association into the massive marls. if we summarize the experience obtained by such analyses of sp and ra curves, not only from the wells on this profile, but from the wells in the depression, in which all or most facies associations are well developed, certain conclusions can be reached. vertical sucfig. 12 distribution map of γ2 sandstone body (iva sandstone) in æutica oil field. • ,~ m <,'~ distrlsunon map orrl sandstone body in zunca oil flelo pio<h .... i;"" of_ _ fa · _i filii", (",i .. ","",,0000 _ f1i • drpooiti .... 1 101:>< f>,ci .. __ _ fe • 1.i<trai and <liltal t\liiiidi .. faci ..... :.ciaiioo. fl>. massive marl &.cia ...... ioii"" «>iiiact m:. of_i a)'si<!iu (v, y<'+rl"'y'''p) ~" • 74 geologia croatica 55/1 cession of the explored deposits usually starts with the massive marl facies association, followed by sandstone beds of the distal turbidite facies assocciation, depositional lobe facies association and channel filling facies association. this part of the succession would correspond to the progradational phase. then again follows the facies association of depositional lobe, distal turbidite facies association, and massive marl facies association. this part of the succession corresponds to a retrogradational phase. these two phases form a cycle of fig. 13 distribution map of γ1 sandstone body (iva sandstone) in æutica oil field. , " ,', ..... distribution m"'1 of i" sandstone body in tunc'" oil field p;"~ 0\11 line of __ _ p", • 0 ........ 1 fiiij". u<j .. _wion _ i'd. oj.epo<;lioll>! lob< u<io/. ___ _ pc · lalerol _ <ilitallllrlli4ito ,.;~ ,-."~, i i'd ...... ivc marl f .. d .. _ ,(ij:; ,ontoctomoofchaod<l ~(oix yo..y,..yj ~, • ~ .. • 75vrbanac: facies and facies architecture of the ivaniê grad formation... sandstone material transport in the depression, comprising the lithostratigraphic unit of the iva sandstones. after a longer period of time in which, over the whole sava depression, sediments of the massive marl facies association were exclusively deposited, except in the part of the kloπtar ivaniê oil field where the distal turbidite facies association was deposited, another relatively long period of time occurred with numerous turbidite currents that brought large quantities of sandstone detritus in the depression. this cycle of deposition of sandy detritus in the depression also consists of progradational and retrogradational phases, and the sediments of this cycle comprise the okoli sandstones lithostratigraphic unit. it can be concluded that sandstone material of the ivaniê grad formation was brought during two cycles of turbidite current movements. each cycle had progradational and retrogradational phases, and corresponds to an extending and narrowing of the depositional area of detrital material (fig. 14). the vertical succession of facies associations in each well is subject to those occurrences of higher order, and to its position in the depositional system. in each member that contains sandstones, the vertical succession of facies associations was dictated mainly by the lateral migration of channel, and afterwards by other numerous factors such as distance from the channel, channel depth, density and size of turbidite cloud, palaeorelief, etc. proximity to distributional channels determines thickness and number of sandstone beds within a sandstone body, as well as the facies association. in the channel, the thickness of sandstone beds and bodies is maximal. it decreases with lateral distance from the channel axis and southwards where the action of turbidite currents gradually weakens. 6. conclusion (1) a double mechanism of transport and deposition of the ivaniê grad formation was defined. massive marls represent “normal” basin hemipelagic deposition (f1 facies). periodic turbidity brought coarser sand-size detritus, as well as finer grained detritus of siltite and mud size, lithification of which formed turbidite facies (f2-f4 facies). (2) marginal parts of the research area were composed exclusively of massive marls deposited in a calm, low energy environment of moderate water depth. however, since these marls are also present in the central parts of the depression, in turbidite beds, it fig. 14 schematic palaeogeographic section of sava basin towards the end of upper pannonian. 76 geologia croatica 55/1 can be concluded that the depositional environment was calm and stable, owing to sufficient water depth that compensated for all water level changes caused by either tectonic movements or cyclic climate changes. this calm environment was disturbed only by temporary turbidity currents which deposited most detritus in the depression. (3) understanding of the lateral and vertical relationships of the four facies associations in the area (oil and gas field) made it possible to understand depositional occurrences in other parts of the explored basin. (4) reconstruction of the lateral extent of facies association starts with channel filling facies association which pass laterally into depositional lobe facies association, and further from the channel axis into the lateral turbidites facies association and finally into the massive marl facies association. the same regularity is noticed in the reconstruction of the vertical succesion of facies associations. (5) detailed reconstruction of the distribution of sand bodies potential hydrocarbon reservoirs above all, spatially defining channel position directs future exploration activities to the most prospective parts of the basin significantly diminishing exploration expenses. (6) accurate understanding of the relationships of the determined facies associations, which are characterised by specific reservoir properties, contributes to defining the strategy of locating development and injection wells in previously discovered oil and gas fields. this will result in the enhancement of recoverable hydrocarbon reserves. acknowledgements an earlier version of this paper was critically read by prof. josip ti©ljar, faculty of mining, geology and petroleum engineering, university of zagreb, prof. h.g. reading, the university of oxford, and dr sc. györgyi juhász, geological institute of hungary, budapest, who contributed extensive and valuable suggestions. i am also grateful to gordan brzica, gordana raffael-guji∆ and neven butina (inanaftaplin) on graphic outfit of the paper. 7. references allen, j.r.l. (1984): sedimentary structures: their character and physical basis.developments in sedimentology, 30, unabridged one-volume edition, elsevier, 593+663 p. bouma, a.h. (1962): sedimentology of some flysch deposits.elsevier, amsterdam, 159 p. bokor, n., devald, m., lu»in, j. & thaller, j. (1979): usporedni prikaz naftnogeoloπkih odnosa u “ i v a-pjeπëenjacima” polja ivaniê grad-æ u t i c a-o k o l i . zbornik radova iii god. znan. skupa zsn jugosl. akad. znan. umjetn. (novi sad), 2, 585-595, zagreb. campbell, c.v. (1967): lamina, lamina set, bed, and bedset.sedimentology, 8, 7-26. clayton, j.l. & koncz, i. (1994): petroleum geochemistry of the zala basin, hungary.am. assoc. petrol. geol. bull., 78 /1, 1-22. dali∆, n. (1996): okoliπ taloæenja i oblici sedimentnih tijela pjeπëenjaka iva naftno-plinskog polja okoli (gornji panon) (sedimentary environment and shape of sediment bodies of iva sandstones of oil and gas field okoli (upper pannonian).unpublished msc thesis (in croatian), university of zagreb, 46 p., zagreb. –urekovi∆, m. (1995): taloæenje i rezervoarska obiljeæja iva pjeπëenjaka na naftnom polju ivaniê (deposition and reservoir characteristics of iva sandstone on oil field ivaniê).unpublished msc thesis (in croatian), university of zagreb, 58 p., zagreb. filjak, r., pletikapi∆, æ., nikoli∆, d. & aksin, v. (1969): geology of petroleum and natural gas from the neogene complex and its basement in southern part of the pannonian basin yugoslavia.in: hepple, p. (ed.): the exploration of europe and north africa. institute of petroleum, 113-130, london. fisher, w.l. (1969): facies characterization of gulf coast basin delta systems, with some holocene analogues.gulf coast assoc. geol. soc. trans., 19, 105-125. galloway, w.e. (1968): depositional systems of the lower wilcox group, north-central gulf coast basin.gulf coast assoc. geol. soc. trans., 18, 275-289. galloway, w.e. (1998): siliciclastic slope and base-ofslope depositional systems: component facies, stratigraphic architecture, and classification.am. assoc. petrol. geol. bull., 82/ 4, 569-595. hamilton, e.l. ( 1967): marine geology of abyssal plains in the gulf of alaska.jour. geophys., 101, 725-728. hámor, g. & bérczi, i. (1999): common issuses of neogene paleogeographic models and petroleum systems.2nd. int. symp. on petroleum geology (probability approach to petroleum exploration), proceedings, 125133, zagreb. kolbuszewski, j. (1950): notes on the deposition of sands.research, 3, 478-483. laughton, a .s. (1968): new evidence of erosion on the deep ocean floor.deep-sea research, 15, 21-29. lowe, d.r. (1975): water escape structure in coarse-grained sediments.sedimentology, 22, 157-204. lowe, d.r. (1976): subaqueous liquefied and fluidized sediment flows and their deposits.sedimentology, 23, 285308. lowe, d.r. (1979): sediment gravity flows: their classification and some problems of application to natural flows and deposits.soc. econ. paleontol. mineral., spec. publ., 27, 75-82. lowe, d.r. (1982): sediment gravity flows ii: depositional model with special reference to the deposits of high-den77vrbanac: facies and facies architecture of the ivaniê grad formation... sity turbidity currents.jour. sed. petrol., 52/1, 279-297. lowe, d.r. & lopiccolo, r.d. (1974): the characteristics and origins of dish and pillar structures.jour. sed. petrol., 44, 484-501. lu»i∆, d. (1994): regressive and transgressive depositional systems and parasequences in the shallow shelf deposits (sava depression, pannonian basin, croatia).liverpool sequence stratigraphy conference, abstracts, 387-388. mattick, r.e., rumpler, j. & phillips, r.l. (1985): seismic stratigraphy of the pannonian basin in southeastern hungary.geophysical transactions, 31, 13-54. middleton, g.v. (1967): experiments on density and turbidity currents, iii: deposition of sediment.canadian jour. earth sci., 4, 475-505. middleton, g.v. (1970): experimental studies related to problems of flysch sedimentation.in: l a j o i e, j. (ed.): flysch sedimentology in north america. geol. assoc. of canada, spec. paper, 7, 253-272, toronto. milju©, p. & vugrinec, j. (1977): neke osnovne crte geoloπke grae sjevernog dijela hrvatske i karakteristike nakupljanja ugljikovodika.nafta, 22/7-8, 425-4 3 9 , zagreb. mutti, e. & ghibaudo, g. (1972): un esempio di torbiditi di conoide sottomarina esterna: le arenarie di san salvatore (formazione di bobbio, miocene) nell’ accademia de piacenza.memorie dell’ accademia delle scienze di torino, classe di scienze fisiche, matematiche e naturali, 4/16, 40 p. mutti, e. & ricci lucchi, f. (1975): turbidite facies and facies associations.in: examples of turbidite facies and associations from selected formations of the northern apennines. ix int. congress of sedimentology, field trip a-11, 21-36, nice. pirson, s.j. (1970): geologic well log analysis.gulf publ. co., houston., 370 p. pletikapi∆, æ. (1965): stratigrafija, paleogeografija i naftoplinonosnost ivaniê grad formacije na obodu moslavaëkog masiva (stratigraphy, paleogeography and oil gas possibilities of the ivaniê grad formation on the border of the moslavaëka gora range).unpubl. phd thesis, university of zagreb, 71 p. postma, g. (1986): classification for sediment-gravity flow deposits based on flow turbidites: a mechanism for their emplacement.sediment. geol., 58, 47-61. reineck, h.e. & singh, i.b. (1973): depositional sedimentary environments.springer verlag, new york, heidelberg, berlin, 439 p. sanders, j.e. (1965): primary sedimentary structures formed by turbidity currents and related resedimentation mechanisms.in: middleton, g.v. (ed.): primary sedimentary structures and their hydrodynamic interpretation. soc. econ. paleontol. mineral., spec. publ., 12, 192-219. selley, r.c. (1976): subsurface environmental analysis of north sea sediments.am. assoc. petrol. geol. bull., 60/2, 184-195. selly,r.c. (1985): ancient sedimentary environments and their sub-surface diagnosis.iii edition, cornell university press, ithaca, new york, 317 p. sütö-szentai, m. (1982): organic microplantonic and sporomorphous remains from the pannonian from the borehole tengelic-2.ann. inst. geol. publ. hung., 65, 205-233, budapest. syed, a.a. (1979): recognition of sandstone depositional environments from well logs.gulf co. int. publ., 57 p. szentgyörgyi, k. & juhasz, gy.k. (1988): sedimentological characteristics of the neogene sequences in sw transdanubia, hungary.acta geologica hungarica, 31/3-4, 209-225. ©∆avni»ar, b. (1979): pjeπëenjaci pliocena i miocena savske potoline.iii god. znan. skup zsn jugosl. akad. znan. umjetn. (novi sad, 1977), zbornik radova, ii, 351-382, zagreb. ©imon, j. (1980): prilog stratigrafiji i taloænom sustavu pjeπëanih rezervoara sava-grupe naslaga mlaeg tercijara u panonskom bazenu sjeverne hrvatske (contribution to stratigraphy and depositional system of sandstone reservoirs of sava group younger tertiary deposits in pannonian basin, northern croatia).unpublished phd thesis (in croatian), university of zagreb, 66 p. vrbanac, b. (1989): okoli pjeπëenjaci juænog dijela naftoplinonosne strukture æutica (okoli sandstones of southern part of oil and gas structure æutica).unpublished msc thesis (in croatian), university of zagreb, 105p. vrbanac, b. (1990): neki rezultati istraæivanja naslaga litostratigrafske jedinice pjeπëenjaci okoli naftoplinonosne strukture æutica.nafta, 41/11, 475-492, zagreb. vrbanac, b. (1996): paleostrukturna i sedimentoloπka analiza gornjopanonskih naslaga formacije ivaniê grad u savskoj depresiji (paleostructural and sedimentological analysis of upper pannonian deposits of ivaniê grad formation in sava depression).unpublished phd thesis (in croatian), university of zagreb, 125 p. walker, r.g. (1978): deep-water sandstone facies and ancient submarine fans: model for exploration for stratigraphic traps.am. assoc. petrol. geol. bull., 62/6, 932-966. manuscript received september 1, 2000. revised manuscript accepted may 20, 2002. 78 geologia croatica 55/1 brkic.indd 283 � ab stra ct the quantity and spatial distribution of groundwater in croatia is determined by geological composition, climate and hydrological conditions and the hydrogeological characteristics of individual areas. northern croatia is part of the southern margin of the pannonian basin and is dominated by the spacious lowlands of the sava and drava rivers, where aquifers of intergranular porosity of pleistocene and holocene ages were formed. the lithological composition of the aquifers is dominated by gravel and sand in the western parts of the drava and sava basins. sandy aquifers are prevalent in the central and eastern parts. groundwater accumulated in these aquifers is the basis of the water supply in northern croatia, which is the reason why monitoring of its status, both quantitative and qualitative is exceptionally important. data obtained by long-term monitoring of groundwater levels facilitated assessment of the quantitative status of groundwater. to determine the causes of changes in the hydrodynamic conditions of the aquifers, results of long-term monitoring of precipitation and stages of the drava and sava rivers were also used. linear regression was used to analyse changes in groundwater levels, the drava and sava river stages and precipitation quantities. the results generally show that there is a negative groundwater level trend over almost the entire area of the drava and sava alluvial aquifer. this is a consequence of deepening of the drava and sava river beds and lowering of their stages, together with a decreasing trend of total annual precipitation. keywords: monitoring, groundwater level trend, stages of the drava and sava rivers, precipitation the quantitative status of groundwater in alluvial aquifers in norther croatia � željka brkić, ozren larva and kosta urumović department of hydrogeology and engineering geology, croatian geological survey, sachsova 2, zagreb, croatia; (zeljka.brkic@hgi-cgs.hr) doi: 104154/gc.2010.23 geologia croatica 63/3 283–298 27 figs. 2 tabs. zagreb 2010 geologia croaticageologia croatica 1. introduction the eu water framework directive (wfd, 2000/60/ec) stipulates determination of the quantitative status of groundwater, the basic indicator of which is groundwater levels. according to the directive, good quantitative status is assigned to groundwater bodies or groups of groundwater bodies where, despite long-term water abstraction in an area, there is no lowering of groundwater levels. groundwater exploitation does not disturb the sustainability of terrestrial and aquatic ecosystems depending on groundwater, while enabling a long-term water supply to the population (fig. 1). therefore, renewable groundwater resources within one or more groundwater bodies contain groundwater which can be exploited (available groundwater resources) for different purposes (water supply, irrigation), as well as the groundwater resources necessary for sustainability of ecosystems (groundwater inviolable fl ow). good quantitative status is assigned to such a groundwater body within which the groundwater abstraction quantity is less than or equal to the resources available for exploitation. the good quantitative status of groundwater is strongly related to the assessment of safe yield the term that has been geologia croatica 63/3geologia croatica 284 used in hydrogeological practice for years. it can be assessed for an aquifer or part of an aquifer at different scales, i.e. for abstraction sites, particular groundwater bodies or entire basins. in literature published in english, there are several synonyms used in connection with sustainable groundwater management, e.g. safe yield, sustainable yield and renewable yield. although many professionals use them readily, there is still ambiguity regarding their exact meaning and what they actually represent (alley & leake, 2004; kalf & woolley, 2005). while this provides an ongoing discussion, it is important to understand that safe yield not only takes into account mass balance assessment, but also other constraints e.g. ecological, socio-economic and groundwater quality requirements. alluvial aquifers in northern croatia are the primary source of water supply in this area, so knowledge of their quantitative status is important, both to this region and for the republic of croatia as a whole. these aquifers are recharged by infi ltration of precipitation and water from surface flows. within the investigation, trend analyses of groundwater levels, the sava and drava river water levels, and precipitation quantities were carried out by linear regression. finally, groundwater exploitation quantities were compared to fi gures for renewable groundwater resources. the primary objective of this study was to assess the quantitative status of groundwater pursuant to the requirements of the eu water framework directive. 2. geological and hydrogeological setting the spatial distribution and lithological composition of the quaternary alluvial aquifers in the drava and sava lowland is signifi cantly different (fig. 2). the drava quaternary aquifer gradually deepens from the west towards the east. in the drava basin, sediments were mainly transported by the drava river, although the infl uence of transport from the northern and southern areas cannot be neglected. due to the ever-decreasing longitudinal fall of the drava from the west to the east, the average size of sedimentary gravel and sand particles also gradually decreases in this direction. in the western part of the drava basin, sand was deposited with gravel. in the central part, there is both lateral and vertical separation in the deposits of gravel and sand, while from virovitica downstream, medium to fi ne-grained uniform sand dominates the aquifer. distinct sand layers are also located within gravel layers in the westfigure 1: good quantitative status of groun d water according to the understanding of water framework directive (according to rejman, 2007). ern area, indicating occasional energy decreases in the water fl ow. however, the full lithological cross section of the drava aquifer generally shows an even distribution of unconsolidated sediments, from the largest particle sizes in the west to the smallest in the easternmost parts of the basin (urumović et al., 1994). the lateral extent of the quaternary aquifer in the sava basin is signifi cantly less developed than in the drava basin (fig. 2). there are numerous local lowered and elevated tectonic structures along the sava river basin with the resulting local increase or decrease in aquifer thickness. in the western part of the sava basin, the aquifer mostly consists of gravel with sand. downstream of sisak, there is marked heterogeneity in the quaternary deposits largely corresponding to the asymmetry of the sava basin. here, the sava’s right tributaries (the una, vrbas, ukrina and bosna rivers) play an important role, both in terms of the size of discharge and the process of sedimentation of coarse-grained clastic sediment. in croatia, the gravelly-sandy sediment of the sava’s right tributaries belongs to the distal fan deposits which have been deposited by these rivers. the majority of the gravelly deposits of the vrbas, ukrina and bosna rivers are located in bosnia-herzegovina. between these gravelly-sandy fan deposits and the faults which separate the sava basin from moslavačka gora mountain and the slavonian range, the quaternary alluvial aquifer is poorly developed (fig. 2). in this area, there are deep subartesian and artesian aquifers of pliocene and early pleistocene age. alluvial aquifers in northern croatia are mostly covered with semi-permeable silty-clayey deposits (aquitard). in the westernmost parts of both lowlands, aquitard thickness is generally low (< 1m) and in many places there is no cover at all or only soil is present. further downstream, the thickness generally increases attaining up to 50−70 m in the easternmost parts (fig. 3). groundwater levels in alluvial aquifers in northern croatia have been monitored for a long period of time. national monitoring and data collection is carried out by the state meteorological and hydrological service. in addition, groundwater levels are also monitored in the catchments areas of public water supply abstraction sites. the monitoring network includes many piezometers installed for different purposes mostly between 1950 and 1990. in the drava aquifer area, most piezometers are located in the western areas and were installed for purpose of design and monitoring of hydropower plant operation (fig. 3). downstream of virovitica, monitoring of groundwater levels is generally carried out by relatively shallow piezometers, which tap more permeable deposits within the aquitard, as observed by miletić et al. (1971). in the alluvial aquifer in the sava river valley, more comprehensive monitoring of groundwater levels is only carried out in the greater zagreb area, and even here, the piezometer network was mostly developed for the planned hydropower plants. however, there is also a groundwater level monitoring network in the zagreb area developed in the catchment areas of the major pumping sites. the majority of piezombrkić et al: the quantitative status of groundwater in alluvial aquifers in norther croatia geologia croatica 285 fi gu re 2 : h yd ro ge ol og ic al p ar am et er s o f t he m ai n al lu vi al a qu ife rs in n or th er n cr oa tia a nd g en er al g ro un dw at er fl ow d ire ct io n. geologia croatica 63/3geologia croatica 286 fi gu re 3 : m on ito rin g ne tw or k fo r g ro un dw at er a nd su rf ac e w at er le ve ls a nd th ic kn es s o f a qu ita rd in n or th er n cr oa tia . brkić et al: the quantitative status of groundwater in alluvial aquifers in norther croatia geologia croatica 287 eters are relatively shallow and tap the unconfi ned aquifer. in the eastern part of the zagreb area, a somewhat larger number of piezometers have been drilled with the aim of monitoring groundwater levels along the depth of the aquifer system. between zagreb and sisak, the piezometer network in the main aquifer is very sparse. in contrast, a larger number of piezometers were installed to monitor groundwater levels in the aquitard above the aquifer. downstream of sisak, the piezometer network is virtually non-existent; monitoring of groundwater levels is carried out only at the existing abstraction sites of public water supply. in the area of spačvanska šuma (spačva forest) in eastern croatia, there are several shallow piezometers at which groundwater levels are also monitored in the aquitard and aquifer. in total, the state meteorological and hydrological service monitors about 430 piezometers in the drava river basin and about 440 in the sava river basin. the general direction of groundwater fl ow is shown in figure 2. in the drava lowland, there is dominant groundwater drainage into the drava river. recharge from surface water bodies is related to the accumulation lakes built for hydropower plants along the drava river and, during fl oods, to the inundation area of the drava and danube. in the westernmost part of the sava lowland, the alluvial aquifer is recharged by infi ltration from the sava river, which is further enhanced due to intense groundwater abstraction at the zagreb abstraction sites. in the stretch from zagreb to sisak, on the right sava bank, the aquifer is recharged from the sava river during high stage periods, whereas the river itself drains groundwater during low-stage periods. 3. data and methods the assessment of quantitative groundwater status was carried out by analysing a time series of groundwater levels, stages of nearby rivers and precipitation quantities. the following data were included. 1. time series of groundwater levels data from 1997−2007 (11 years inclusive). the locations of piezometers were selected so that profi les were formed approximately perpendicular to the water gauging stations on the drava and sava rivers (fig. 3). these data were in some places also supplemented by a time series of groundwater level data for different periods (1987−2001 on the left drava river bank upstream of the gauging station 5115, 1995−2005 in the varaždin area and 1988-2003 in the zagreb area). in baranja, monitoring was not carried out during and after the homeland war and was only established in mid-2001. data analysis showed that the groundwater level trend in baranja from 2002 to 2007 was the opposite of the one in the period from 1997 to 2007 on all piezometers analyzed in the upstream area of the drava basin i.e. that in that period there was an increasing trend in groundwater levels. in order to determine the reason for these differences, time series of data were analyzed for the periods from 1997 to 2007, 1997 to 2001 and 2002 to 2007 on piezometers located outside baranja. the same was also undertaken for the gauging stations (5009, 5150, 5054) (fig. 3) on the dra-va river and for precipitation quantities at the varaždin, virovitica and osijek meteorological stations. 2. the time series of stage data on the drava and sava rivers for the period 1997−2007 (11 years): at 8 water gauging stations on the drava river (5067, 5115, 5009, 5098, 5064, 5150, 5005 and 5054) and 7 water gauging stations on the sava river (3066, 3332, 3096, 3373, 3335, 3098, 3211) (fig 3). at the beginning of the 1990’s, a river dam was built near the te-to thermal power plant on the sava river at zagreb. in order to identify the impact of the river dam on the groundwater levels, water levels at the gauging station 3121 (fig. 3) are shown for the period from 1978 to 2008. 3. time series of precipitation data at 4 main meteorological stations (varaždin, osijek, zagreb – pleso airport, sisak) and 1 rainfall gauging station (virovitica) for the period 1997 − 2008 (12 years) and for the period 1978 − 2008 (30 years). 4. abstraction rates of groundwater at individual abstraction sites (based on issued concessions) (croatian waters, 2007). 5. estimated renewable groundwater resources (gereš, 1998; mayer, 1996; urumović et al., 1994; brkić & mayer, 2005). 6. hydrogeological characteristics of the aquifers (aquifer geometry, aquifer type – unconfi ned, confi ned, semiconfi ned, hydrogeological parameters, groundwater fl ow direction) deposited in the drava and sava basins. the hydrographs for 23 piezometers are comprehensively presented in the paper. table 1 shows the four main characteristics of these piezometers: (1) depth interval of the screen in m, (2) tapped layer, (3) type of aquifer, and (4) approximate distance from the drava or sava rivers or hydropower plant drainage canal in m. the type of aquifer in some cases varies between unconfi ned and semi-confi ned, depending upon the water regime and the position of a water table. the data quality was checked by visual inspection of the hydrograph at each considered piezometer and also during construction of a head equipotential map. data anomalous to the regional scheme of groundwater fl ow, as a result of measurement errors or storage data errors, were neglected. linear regression analyses were undertaken on the time series of the groundwater levels, river stages and precipitation data. this is frequently used when it is necessary to defi ne the nature of a connection between two or more variables. two procedures were applied: correlation and trend analysis. in the case of correlation analyses, the pearson’s correlation coeffi cient value is critical for determination of linear connection strength. if the connection between the variables is functional, i.e. full, the pearson’s correlation coeffi cient would be 1. in all other cases, it would range from 0 to 1. if the linear connection is strong, it is closer to 1, while in the case of the weak connection it is closer to 0. analysis of the determined trends of groundwater levels, water levels of the drava and sava rivers and precipitageologia croatica 63/3geologia croatica 288 tion quantities, as well as existing groundwater exploitation quantities and estimated renewable resources, allowed defi nition of the quantitative status of groundwater in the alluvial aquifers in the drava and sava basins. 4. results and discussion 4.1. hydrodynamic conditions of the drava aquifer analysis of groundwater levels in the drava aquifer shows an observable lowering trend in nearly all analyzed locations (fig. 3). piezometers in areas immediately surrounding the accumulation lakes for the hydropower plants along the drava river in the wider varaždin area (fig. 4) are the only exceptions. here, groundwater levels are dominantly under the infl uence of the lakes. since the drainage canals surrounding the accumulation lakes have only a local infl uence, the accumulation lakes recharge the aquifer in the immediate surroundings, preventing or reducing the general trend of a lowering of groundwater levels. groundwater levels are also steady in the infl uence area of the drainage canal stretchtable 1: the basic characteristics of piezometers chosen for presentation. river basin piezometer depth interval of the screen (m) tapped layer type of aquifer approximately distance from the rivers drava or sava, or hydropower plant drainage canal (m) drava and danube 2168 4-8 aquifer unconfi ned 1050   2170 4-8 aquifer unconfi ned 2000   1572 5.5-9.5 aquifer unconfi ned 170   1573 5.5-9.5 aquifer unconfi ned 420   1520 5.5-9.5 aquifer unconfi ned 6000   1593 5.5-9.5 aquifer unconfi ned 2200   2020 3.5-4.5 aquifer unconfi ned 1700   4007 9-15 aquifer unconfi ned/semiconfi ned 450   3012 3-5 aquifer unconfi ned/semiconfi ned 5000   3036 6-10 aquifer unconfi ned/semiconfi ned 13000   4009 6.5-12.5 aquifer unconfi ned/semiconfi ned 200   4052 21-29 aquifer semiconfi ned 7500   4071 76-86 aquifer semiconfi ned 24000   4072 42-54, 78-90, 114-126 aquifer semiconfi ned 2800   4087 8-10 aquitard   23500   4069 50-56, 80-86 aquifer semiconfi ned 9000   4080 8-12 aquifer semiconfi ned 18000 sava 57 8-12.5 aquifer unconfi ned 2800   86 2-8 aquifer unconfi ned 3200   5117 65-70 aquifer unconfi ned/semiconfi ned 4600   388 7-9 aquitard   550   351 11.5-15.5 aquifer semiconfi ned 2200   145 10-14 aquifer semiconfi ned 500 ing from the varaždin power plant to the discharge point (fig. 5). apart from the visual impression, the stability of groundwater levels is also indicated by the low values of regression coeffi cients (figs. 4 & 5). far from the accumulation lakes and drainage canal their impact on groundwater dynamics is weakened (larva, 2008). the annual amplitudes of groundwater levels are more marked, and their negative trend is also evident (fig. 6). downstream of the varaždin area, a general trend of lowering groundwater levels from 1997 to 2007 is observed (fig. 3). figures 7−9. present a time series of groundwater levels at piezometers 1593, 2020, 3012, 3036, 4052, 4071, 4072, 4069 and 4080. between 1997 and 2007, two opposite trends have been observed on most analysed piezometers − a negative groundwater level trend is observed from 1997 to 2001 and a positive one from 2002 to 2007 (figs. 7b, 8b and 9). at piezometers 4071 and 4072, which tap a deeper interval of the aquifer, lowering of groundwater levels was observed in both monitoring periods (fig. 9). the lowering of levels was more marked at piezometer 4071 than at piebrkić et al: the quantitative status of groundwater in alluvial aquifers in norther croatia geologia croatica 289 figure 4: groundwater levels at piezometers 2168 and 2170 located in the vicinity of the right bank of the varaždin accumulation lake with linear trend lines for 1995−2005. figure 5: groundwater levels at piezometers 1572 and 1573 located in the vicinity of the right bank of the drainage canal from the varaždin hydropower plant to the restitution with linear trend lines for 1995−2005. figure 6: groundwater levels trend at piezometer 1520 located in the central part of the varaždin aquifer, far from the drava river, with linear trend line for 1995−2005. figure 7: groundwater levels at piezometers 1593 and 2020 with linear trend lines for (a) 1997−2007 and for (b) 1997−2001 and 2002−2007. figure 8: groundwater levels at piezometers 3012, 3036 and 4052 with linear trend lines for (a) 1997−2007 and for (b) 1997−2001 and 2002−2007. zometer 4072. the latter piezometer taps the shallower part of the aquifer system and is located closer to the drava river, so the groundwater level here is under a stronger infl uence of the river. on the right bank of the drava, but far from the river (table 1), groundwater levels, even at shallower piezometers (4087), had a lowering trend (fig. 10). groundwater levels here are more infl uenced by precipitation. all water gauging stations downstream of the hydropower plants and accumulation lakes show a trend of lowering of drava water levels. the drava stage in the greater varaždin area is affected by the operation of the varaždin, geologia croatica 63/3geologia croatica 290 figure 9: groundwater levels at piezometers 4071, 4072, 4069 and 4080 with linear trend lines for 1997−2007 and 2002−2007. čakovec and dubrava hydropower plants. the water levels in the old drava river channel depend on the water quantities discharged from the accumulation lakes, which, in turn, depends on the water discharged into the lake and on the volume of the lake reservoir. water levels in the accumulation lakes generally vary within 1 m. downstream of the hydropower plants, the drava water levels had a negative trend throughout the entire monitoring period 1997 – 2007 (fig. 11a). however, considering the observed periods separately, the trend was in both cases positive (fig. 11b). figure 10: groundwater levels at piezometers 4071 and 4087, drava water levels at gauging station 5150 and monthly precipitation at the osijek meteorological station. figure 11: drava water levels at the water gauging stations 5009, 5150 and 5054 with l inear trend lines for (a) 1997−2007 and for (b) 1997−2001 and 2002−2007. this difference is the consequence of the factors which infl uence the drava hydrograph. for shorter time intervals, water levels are predominantly infl uenced by climate conditions in the analyzed time interval. for mean annual precipitation in the period from 1997 to 2001, there was an increasing trend in the osijek area, but a decreasing one in the areas of varaždin and virovitica. from 2002 to 2007, there was a registered increase in precipitation (fig. 12) at all observed meteorological stations. the trend of precipitation increase which was registered in the northwestern part of croatia (varaždin) in the period from 2002 to 2007 can also be expected in the upstream stretches of the drava river beyond the croatian borders, which eventually results in increased water levels of the drava in croatia. in the same period, low water levels also showed an increasing trend (fig. 13). this was due to the fact that in the periods of expected low water levels during winter (january and february) and summer (au gust, september), precipitation was higher than the 1997−2007 mean. alternatively, the increasing trend of drava water levels from 1997 to 2001 can probably be attributed to the snow melt in the drava river basin outside croatian borders although decreased precipitation quantities were registered in north western croatia. however, the drava water levels observed throughout the period from 1997 to 2007 showed a trend of decrease. it is a consequence of morphological changes in the drava river bed (river bed erosion) caused by the construction of hydropower plants, regulation of the river and its tributaries, construction of hundreds of kilometres of levees for fl ood protection as well as exploitation of gravel from the river bed (biondić, 1999; bonacci & oskoruš, 2010). the morphological changes in the drava river bed are a relatively slow, long process, which is observed when long time series of the suspended sediment yield are analyzed. these changes are even more marked when the hydrological and sediment regime for the drava is analyzed over several recent decades (bonacci & oskoruš, 2010). it can be concluded from the aforementioned analyses, that the trend of decreased groundwater levels recorded on the piezometers in the period from 1997 to 2001 is a consequence of decreased precipitation in the same time interval. from 2002 − 2007, there were observed trends of increased brkić et al: the quantitative status of groundwater in alluvial aquifers in norther croatia geologia croatica 291 figure 12: total annual precipitation at the varaždin, virovitica and osijek meteorological stations with linear trend lines for 1997–2001 and 2002– 2007. figure 13: minimum annual stages of the drava river at the water gauging stations 5009, 5098, 5064, 5150, 5005 and 5054 with linear trend lines for the period from 2002 to 2007. precipitation and increased drava water levels. it can, therefore, be concluded that over shorter time periods the trend of increased groundwater levels is predominantly infl uenced by precipitation. in a longer time period, however, the trend of decreased groundwater levels is infl uenced by the trend of decreased drava water levels, as observed in the period from 1997 to 2007. downstream of the constructed hydropower plants, ground water does not have a strong connection to the figure 14: correlation coeffi cients between drava river stage at (a) the water gauging stations 5009 and piezometer 4007 and at (b) the water gauging stations 5009 and piezometer 3012. figure 15: drava water levels at gauging station 5009, piezometer 4007 (about 450 m from the river) and piezometer 3012 (about 5 km from the river). figure 16: drava water levels at gauging station 5064, piezometer 4009 (about 200 m from the drava) and piezometer 4052 (about 7.5 km from the drava). changes of the drava river stages, with the exception of the direct proximity of the river. the strongest connection was observed between the water level at the water gauging station 5009 and piezometer 4007 (correlation coeffi cient of 0.93), (fig. 14a), and also between the water level at the water gauging station 5064 and the piezometer 4009 (correlation coeffi cient of 0.7). at about 1.5 km from the drava, the correlation coeffi cient is about 0.3, and far from the river generally about 0.2 (fig. 14b). geologia croatica 63/3geologia croatica 292 in the area of the drava lowland, groundwater drainage into the drava river is dominant, and the aquifer is recharged through infi ltration of precipitation estimated at about 30 % of mean annual precipitation in the western part and about 10 % of mean annual precipitation in the eastern part of the drava valley (urumović et al., 1994). only at high water levels, is the aquifer in the area approximately between the water gauging station 5009 (fig. 15) and the water gauging station 5064 (fig. 16) recharged from the drava river. although the groundwater level trend is similar to the drava water level trend, far from the drava there is frequently no observable reaction of groundwater levels to high water levels in the drava river. any increase in groundwater levels in this area of the drava aquifer is predominantly infl uenced by precipitation. total annual precipitation in the varaždin area ranges from 600 to 1000 mm (figs. 17a and 17b). the lowest precipitation quantities were registered in 2000 and 2003. in the 30-year period, the mean annual precipitation was 825 mm, and in the monitoring period 1997 – 2008 it was 782 mm. in the easternmost area of the drava basin, total annual precipitation ranges from 300 to 950 mm (figs. 17a and 17b). as with the western part, the lowest precipitation quantities were registered in 2000 and 2003. in the 30-year period, the mean annual precipitation was 666 mm (excluded 1991 and 1992, when it was not monitored), and in the monitoring period 1997− 2008 it was 702 mm. in this latter period, the trend of decreased precipitation was recorded. mean monthly precipitation at the meteorological station varaždin from 1978 – 2008 was generally higher than the mean monthly precipitation for the period 1997 – 2008 (fig. 18), with the exception of the means for july and september, which were slightly higher in the period 1997 – 2008. in the same months, the deviation from the mean was also higher. the deviation from the mean annual precipitation was also higher in the period 1997 – 2008 in comparison with the period from 1978 to 2008. in the eastern part of the drava basin, the distribution of precipitation differs from that in the western part. the mean precipitation values were nearly identical in the fi rst half of both observed periods (fig. 19). in contrast, in the second half of the year, they were higher in the period 1997 – 2008 than those in the 30-year period. in this period, the mean precipitation quantity in july and august was 15−20 % higher than that for the 30-year period. in the summer months, deviation from the mean was also higher. the deviation from the mean annual precipitation was also higher in this period in comparison with the period from 1978 to 2008. the distribution of precipitation throughout the year has also altered which has had a signifi cant infl uence on groundwater recharge and consequently on groundwater levels. lower quantities of precipitation have been recorded in the spring and autumn months, while in the summer months there is a trend of increased precipitation. from the prospect of groundwater renewal, increased precipitation during the summer months has a small effect due to evapotranspiration, surface runoff and rebuilding up of soil water budget. such observations are in accordance with the results of the quantitative precipitation analyses for 1901 to 2000 (ministry of environmental protection, physical planning and construction, 2006). the overall annual precipitation trend shows a decrease during the 20th century in the whole of croatia. this decrease is more pronounced in eastern croatia (at the meteorological station osijek 13%) than in north western croatia (at the meteorological station zagreb-grič 3%). the annual distribution of precipitation shows a signifi cant decrease in spring precipitation (osijek 41 %/100 years, zagreb-grič 11 %/100 years) and autumn precipitation (osijek 30 %/100 years , zagreb-grič 14 %/100 years). figure 17: total annual precipitation at the meteorological stations varaždin and osijek with linear trend lines for (a) 1978−2008 and (b) 1997–2008. figure 18: mean values and standard deviations of monthly precipitation at the varaždin meteorological station. brkić et al: the quantitative status of groundwater in alluvial aquifers in norther croatia geologia croatica 293 4.2. hydrodynamic conditions of the sava aquifer in the sava aquifer, monitoring of groundwater levels is carried out at several hundred piezometers in the area from the state border with the republic of slovenia to sisak. downstream of sisak, the piezometer network is virtually nonexistent, and monitoring of groundwater levels is carried out only at the existing abstraction sites of public water supply and in the area of spačvanska šuma (spačva forest) in eastern croatia. the trend of lowering groundwater levels in the zagreb area has been observed over a longer period (trninić & bošnjak, 2008). it appeared as a consequence of the deepening of the sava river bed, and thus the lowering of its water levels, even though the exploitation of large quantities of groundwater for the public water supply of the city of zagreb cannot be neglected as a factor. erosion of the sava, as well as of the drava river bed, is caused by signifi cant morphological changes brought about by the regulation of the river and its tributaries, construction of hundreds of kilometres of levees for fl ood protection and exploitation of gravel from the river bed. in this manner, sediment transfer ceased, which started the process of river bed deepening. interestingly, a detailed analysis of the time series for minimum, mean and maximum annual discharges of the sava at zagreb in the period 1926 – 2006 identifi ed a signifi cant trend of decreased discharge, which indeed indicates a reduction in water quantity (trninić & bošnjak, 2008), with anthropological and climate impacts stated as the causes. at the beginning of the 1990s, the trend of decreasing sava river water levels was stopped by the river dam near thermal power plant te-to zagreb (fig. 20). this also stopped the trend of decreasing groundwater levels in the small area upstream of the power plant (fig. 3). this is particularly marked on the left river bank where, among other factors, there is no signifi cant groundwater exploitation. in the remaining zagreb area, the trend of decreased groundwater levels was observed on almost all piezometers and in all parts of the aquifer system (fig. 3). figure 21 presents a time series of groundwater levels at piezometers 86, 57 and 5117. piezometer 86 is located upstream of the abstraction site for public water supply and piezometer 57 is located upstream of the power plant on the left river bank (fig. 3). in contrast, piezometer 5117 is located in the eastern part of zagreb where there is no signifi cant groundwater exploitation. figure 19: mean values and standard deviations of monthly precipitation at the osijek meteorological station (without data for 1991 and 1992). figure 20: sava water levels at water gauging station 3121 with linear trend lines for the period 1978−1993 and 1994−2007. figure 21: groundwater levels at piezometer 57 upstream of the multipurpose reservoir of the te-to on the sava left bank, and piezometers 86 and 5 117 on the sava right bank with linear trend lines for the period 1988−2007. lowering of groundwater levels in the zagreb area is also related to the large abstracted water quantities at the abstraction sites, i.e. aquifer over-abstraction (bačani & posavec, 2008; 2009). it is undeniable that abstraction of large quantities of water impact on the lowering of groundwater levels; however, they are not the main reason for it. total abstracted quantities at the abstraction sites in zagreb in the period 1988 – 2008 changed depending on consumer demand. in the period 1988 – 1993 they equalled about 120 million m3/year, in the period 1993 – 2000 there was a slight increase in the abstracted quantities whereas since 2000 there has been an evident trend of their decrease (fig. 22). the reason for the decrease in abstracted quantities is attributed to decreased industrial consumption and to the fact that, even though the number of individual consumers has increased, there is a slight decrease in consumption per capita (kočo & iličić, 2009). geologia croatica 63/3geologia croatica 294 figure 22: total abstracted quantity at the abstraction sites in zagreb for 1988–2008 (according to kočo & iličić, 2009). figure 23: sava water levels at water gauging stations 3096 and 3335 with linear trend lines for 1997−2007. figure 24: groundwater levels at piezometers 388, 351 and 145 on the right bank of the sava river with linear trend lines for 1997−2007. 1 bačani, a., posavec, k., nakić, z., perković, d., miletić, p., heinrich-miletić, m., parlov, j. & bazijanec, m. (2005): elaborat zaštitnih zona vodocrpilišta grada zagreba. [study of protection zones of the city of zagreb water abstraction sites – in croatian].− unpubl. report, faculty of mining, geology and oil engineering, university of zagreb, zagreb, 374 p. although there has been a decrease in the abstracted quantities in the zagreb area in recent years, the trend of lowering of groundwater levels has not stopped. the same situation is also recorded in the easternmost part of the zagreb aquifer. a negative groundwater level trend is recorded at nearly all piezometers (fig. 3), regardless of aquifer depth at which groundwater levels are measured, as was observed at piezometer 5117 (fig. 21). groundwater levels show a strong connection to changes in the sava water levels in the zagreb area. a strong connection, described by a correlation coeffi cient > 0.6, was determined at a distance of about 1 km from the sava in the western and central parts of the zagreb area. in the eastern part of the zagreb area, a strong connection was determined at distances of 2, and even 5 km, from the sava river (borčić et al, 1968). statistical analyses of groundwater levels and the sava river stages conducted recently show the same results (bačani et al., 2005)1. in the sisak area, at 320 m from the sava river, a strong connection was determined, with a correlation coefficient of 0.79 (larva, 2002). however, where the overlying aquitard is greater than 20 m thick, and the aquifer is not in direct contact with the sava river, a different situation occurs. about 100 m away from the sava, the correlation coeffi cient is 0.42. the sava water levels downstream of zagreb show the same trend (fig. 23) in line with the trend of negative groundwater levels the water gauging stations which are furthest downstream in croatia, at slavonski brod (station 3098), and županja (station 3211), show the same negative trend. between zagreb and sisak, there is also a prevalent negative trend concerning groundwater levels (figs. 3, 24), although there is no groundwater exploitation in the area. total annual precipitation ranges from 700 to 1100 mm in the zagreb area and from 600 to 1100 mm in the sisak area (figs. 25a and 25b). the lowest precipitation was registered in 2003. in the 30-year period, the mean annual precipitation at the zagreb meteorological station was 934 mm and 932 mm in the monitoring period 1997 − 2008. the time series of total annual precipitation in the period 1978 – 2008 (30 years) in the zagreb area showed the absence of any meaningful trend. however, analysis of precipitation data in the last 12 years (1997 – 2008) evidently showed a trend of precipitation decrease (fig. 25b). the same changes have also been observed at the sisak meteorological station (fig. 25b). between 1997 – 2008 there has also been marked lower precipitation during may and june, as in the varaždin area, which is slightly higher in the summer months (figs. 26 and 27). in general, there is an evident trend of increased precipitation during summer months (july, august and even september). at both meteorological stations, the deviation from the mean annual precipitation was higher between 1997 – 2008 compared to the period from 1978 to 2008. brkić et al: the quantitative status of groundwater in alluvial aquifers in norther croatia geologia croatica 295 figure 25: total annual precipitation at the za g reb and sisak meteorological stations with linear trend lines for (a) 1978 2008 and (b) 1997–2008. figure 26: mean values and standard deviations of monthly precipitation at the zagreb-pleso meteorological station. figure 27: mean values and standard deviations of monthly precipitation at the sisak meteorological station. 4.3. renewable groundwater resources in the alluvial aquifers and abstraction rates groundwater resources in alluvial aquifers were estimated several times and by several methods. one was based on the estimation of renewable resources as the product of the aquifer surface area and effective infi ltration coeffi cient (urumović et al, 1994). another calculated renewable sources as either a product of the aquifer surface, difference between maximum and minimum groundwater levels and layer porosity (unconfi ned aquifer) or a product of aquifer surface, difference between maximum and minimum piezometric pressures and coeffi cient of aquifer storage (confi ned aquifer) (mayer, 1996). the determination of renewable ground water resources has always been infl uenced by numerous unknowns due to an insuffi cient quantity of measured data, thus the larger part of the area was estimated on the basis of analogy with better investigated areas. usually, two values for renewable groundwater resources in alluvial aquifers are quoted (gereš, 1998), one related to the minimum and the other to the maximum estimate. the differences between those are extremely large, e.g. for the sava basin, the difference between the minimum and maximum estimates of renewable resources is about 1:6, while for the drava and danu be basin it is about 1:2 (table 1). for purposes of the de velopment of the water management strategy in the republic of croatia (croatian waters, 2009), a new estimate of renewable resources was made (brkić & mayer, 2005). the same methodology as in the previous esti mates was applied. renewable resources were determined in quantities closer to the earlier minimum estimates for the aquifer in the sava valley and are closer to the earlier higher estimated values for the drava aquifer. accordingly, in the areas of the drava and sava aquifers the renewable groundwater resources were estimated at quantities exceeding 1 billion m3/year (table 2). based on concessions issued to water companies and industry, about 115 million m3/year are abstracted from the alluvial aquifer in the drava basin and about 230 million m3/ year from the aquifer in the sava basin. water quantities used for domestic water supply (which is not included in the public water supply system) should be added to these abstracted quantities, as should the quantities used for irrigation. while the data on domestic water supply quantities remain unknown, there is an estimate on water quantities used for irrigation. they range from 15 to 20 ´ 106 m3/year and also include water loss in irrigation systems (croatian waters, 2009). the estimate refers to the whole croatian territory and, in addition to groundwater quantities, also includes surface water used for irrigation. although a reliable estimation of groundwater quantities used for irrigation and domestic water supply are still lacking, it could be concluded geologia croatica 63/3geologia croatica 296 that this is still a small proportion of renewable groundwater resources. when comparing exploited groundwater quantities (based on issued concessions) and estimated renewable groundwater resources, it is evident that only a small proportion of available renewable resources is presently used (15−20%) and that the potential safe yield is much higher. the largest share of abstracted quantities in relation to renewable resources is registered in the zagreb area, where the sava river share in the renewal of waters at abstraction sites is about 67% (bačani et al., 2005)1. the limiting factor for groundwater abstraction at the abstraction sites on the right sava river bank in the zagreb area is the small thickness of the aquifer. this is particularly marked in the dry, summer months, when, due to low water levels of the sava and consequent low groundwater levels, the aquifer transmissivity, which regulates the amount of induced recharge of the aquifer from the sava river, is signifi cantly reduced. one of the most important questions is whether renewable groundwater resources also mean water quantities that can be permanently exploited? in the past, the volume of recharge to an aquifer was accepted as the maximum quantity of water that could be removed from an aquifer on a sustainable basis (the so-called safe yield) (lee, 1915; todd, 1959). nowadays, according to the eu water framework directive (wfd-2000/60/ec), the sustainable yield of an aquifer must be considerably less than recharge, if adequate amounts of water are to be available to sustain both the quantity and quality of streams, springs, wetlands and other groundwater-dependent ecosystems (sophocleous, 2000). if pumping equals recharge, eventually streams and wetlands may dry up. additionally, the practice showed that despite large estimated quantities of renewable groundwater resources at the regional level, there are still diffi culties in ensuring suffi cient water abstraction quantities at individual locations. considering the possibility of induced aquifer recharge during groundwater abstraction, the actual abstracted quantities depend on the hydrogeological conditions of an individual location, spatial distribution of an abstraction sites, and position of a well(s) in relation to constant head boundary, groundwater quality and the needs of groundwater-dependent ecosystems. based on the above, exploitation of groundwater resources should be separately determined for each selected location. for these purposes, mathematical modelling of the groundwater fl ow is often applied. it represents a powerful management tool that can serve multiple purposes, such as providing a framework for the verifi cation of hydrogeological properties and for defi ning the quantitative prediction of the responses of aquifer systems to externally applied stress, (e.g. increase in pumping rates). the availability of the input data determines how many of these problems can be solved. 5. conclusions several conclusions can be drawn from analyses conducted on the time series data of groundwater levels, drava water levels and precipitation in the drava river basin. when considering the time series from 1997 to 2007, the trend of decreasing groundwater levels in the aquitard and in the shallower parts of unconfi ned and semi-confi ned aquifers is un der the predominant infl uence of decreasing levels of drava river water. the decrease of the drava water levels is infl uenced by morphological changes caused by the construction of hydrotechnical facilities. the morphological changes in the river bed are slow, lengthy processes, the consequences of which are refl ected in the gradual decrease in the drava water levels, and can be observed when analyzing longer time series. however, considerations of shorter time intervals show that the trend of groundwater levels and dra va water levels determined from 1997 to 2001 and from 2002 to 2007 is under the predominant infl uence of climate conditions in the observed time interval. from 1997 to 2001, there was a trend of decreased groundwater levels as well as a trend of decreased precipitation, while from 2002 to 2007 there was a determined trend of increased mean annual precipitation and increased groundwater levels. in deeper parts of the aquifer, the drava infl uence on the groundwater is subdued. groundwater fl ow in these areas has a regional character, both according to temporal and spatial criteria. infi ltrated precipitation percolates underground with different retention times that depend on soil humidity, depth of grotable 2: estimated renewable groundwater resources in the drava and sava alluvial aquifers.   renewable groundwater resources (x106 m3/year)   gereš (1998) mayer (1996) urumović et al. (1994) brkić & mayer (2005)river basin min. estimation max. estimation drava and danube river basin – alluvial aquifer 499 556 569 1062 810 sava river basin – alluvial aquifer 1220 7109 1287   1198 1 bačani, a., posavec, k., nakić, z., perković, d., miletić, p., heinrich-miletić, m., parlov, j. & bazijanec, m. (2005): elaborat zaštitnih zona vodocrpilišta grada zagreba. [study of protection zones of the city of zagreb water abstraction sites – in croatian].− unpubl. report, faculty of mining, geology and oil engineering, university of zagreb, zagreb, 374 p. brkić et al: the quantitative status of groundwater in alluvial aquifers in norther croatia geologia croatica 297 und water levels, hydraulic characteristics of the aquitard, its thickness and on the type of vegetation, as well as on the length between recharge zone and observation point. due to this retention time, groundwater levels in the deeper parts of the aquifer are not infl uenced by the relatively short-term trends of precipitation increase, but by a decrease observed over a longer period. accordingly, the lowering of groundwater levels is a consequence of the mutual impact of a multi-year decrease in the total annual precipitation and a multi-year lowering of the drava water levels. in the sava basin, the situation is somewhat more complex. the trend of lowering of groundwater levels in the zagreb area is a consequence of the trend of decreased water levels of the sava river, a decreased total annual precipitation and the exploitation of large quantities of groundwater. the lowering of groundwater levels is also evident downstream of this area, although not as much marked. a decrease of total annual precipitation from 1997 to 2008 was determined in the entire observed area, and it has an important role in groundwater renewal. moreover, an altered distribution in precipitation throughout the year has been noticed, which certainly has signifi cant infl uence on groundwater recharge and consequently on groundwater levels. lower precipitation was recorded in the spring and autumn months, while in the summer months there is a trend of increased precipitation. from the aspect of groundwater renewal, greater precipitation during the summer months has a small effect due to evapotranspiration, surface runoff, and rebuilding of the soil water budget. according to the eu water framework directive (wfd-2000/60/ec), the assessment of groundwater status and risk is, among other things, based on the water needs of ecosystems depending on groundwater. based on the guidelines on protection measures in areas of the national ecological network (natura 2000), the problem of lowering of groundwater levels is not highlighted; only the need for preservation of the existing state of waters is emphasized in special cases. although the lowering of groundwater levels is being recorded, due to relatively large groundwater resources the quantitative status of waters (from the standpoint of the public water supply), in the larger part of the investigated area is presently not endangered, nor will be in the near future. however, the zagreb area could be categorized as “potentially at risk” due to the relatively large quantities exploited and demands for water as well as evident lowering of groundwater levels. such a complex situation requires measurement of numerous parameters (water levels, discharges, sediment transfer in the sava river, groundwater levels, abstracted groundwater quantities, climate changes), their systematic analysis and quantifi cation of anthropological infl uences. the present knowledge of groundwater status must be improved by the application of more sophisticated methods that integrate land use, vegetation, climate, and interacting water. in order to achieve the goals, a multidisciplinary approach must be applied which gathers experts from different fi elds, such as hydrogeology, biology, hydrology, chemistry, etc. additional improvements of the piezometer network in the areas of the drava and sava basins are also necessary. this primarily relates to the area east of virovitica, on the right bank of the drava river, where groundwater levels are presently monitored only in the overlying aquitard and also east of sisak, in the sava river basin, where presently there is no monitoring of groundwater levels at all. the piezometer network must be designed in a manner to enable measurement of groundwater levels in aquifers exploited at abstraction sites within the public water supply, but also in aquifers abstracted for other uses (irrigation, etc.). along with the satisfactory monitoring network, mathematical modelling of groundwater fl ows would enable simulations of different infl uences on the aquifer system within entire alluvial basins on the regional scale. this would create a basis for the optimal management of this important resource of the republic of croatia. acknowledgement the authors wish to express their gratitude to croatian waters for fi nancial support for the research. the authors also wish to thank anonymous reviewers for their very useful comments. this paper represents part of a hydrogeological investigation within the project entitled “basic hydrogeological map of the republic of croatia” (project no. 181-1811096-3165) which is fi nanced by the ministry of science, education and sports. references alley, v.m. & leake, s.a. (2004): the journey from safe yield to sustainability.− ground water, 42/1, 12−16. bačani, a. & posavec, k. (2008): podzemne vode na području grada zagreba. [groundwater in the city of zagreb area – in croatian]. savjetovanje “zagrebačke vode”, kigen, zagreb, 79−93. bačani, a. & posavec, k. (2009): kvantitativno stanje podzemnih voda na području grada zagreba. [quantitative status of groundwater in the city of zagreb area – in croatian]. − znanstvenostručni skup “vodoopskrba grada zagreba stanje i perspektive”, zagrebački holding d.o.o., zagreb, 7−14. biondić, d. (1999): erozija korita donje drave [lower drava riverbad erosion – in c roatian]. građevinar, 51/5, 321−329. bonacci, o. & oskoruš, d. (2010): the changes in the lower drava river water level, discharge and suspended sediment regime.− environmental earth sciences, 59, 1661−1670. borčić, d., capar, a., čakarun, i., kostović, k. & miletić, p. (1968): noviji podaci o zavisnosti vodostaja podzemne vode i vodostaja save na području zagreba [recent data on groundwater levels and water levels of the sava in the zagreb area – in croatian].− geol. vjesnik, 21, 311−317. brkić, ž. & mayer, d. (2005): istraženost slatkih podzemnih voda u republici hrvatskoj [investigation status of fresh groundwater in the republic of croatia – in croatian].− znanstveno-stručno glasilo hrvatske udruge naftnih inženjera i geologa, ina − industrija nafte d.d., zagreb, 1 14. gereš, d. (1998): water resources in croatia.− proceedings − international symposium on water management and hydraulic engineering, 109−117. croatian waters (2009): strategija upravljanja vodama [water management strategy – in croatian].− hrvatske vode, zagreb, 165 p. kalf, f. & woolley, d. (2005): applicability and methodology of determining sustainable yield in groundwater system.− hydrogeology journal, 13, 295−312. geologia croatica 63/3geologia croatica 298 kočo, i. & iličić, k. (2009): dignuta voda u vodoopskrbi grada zagreba u razdoblju od 1945. do 2008. godine [abstracted water for the city of zagreb water supply in the period 1945 –2008 – in croatian].− znanstveno-stručni skup “vodoopskrba grada zagreba − stanje i perspektive”. zagrebački holding d.o.o., zagreb, 45−50. larva, o. (2002): mogućnosti eksploatacije podzemne vode iz aluvijalnog vodonosnika između zagreba i siska [possibilities of groundwater exploatation from the alluvial aquifer between zagreb and sisak − in croatian, with an english abstract].− unpubl. master’s thesis, faculty of mining, geology and oil engineering, university of zagreb, 102 p. larva, o. (2008): ranjivost vodonosnika na priljevnom području varaždinskih crpilišta [aquifer vulnerability in the recharge area of the varaždin abstraction sites – in croatian, with an english abstract].− unpubl. phd thesis, faculty of mining, geology and oil engineering, university of zagreb, 198 p. lee, c.h. (1915): the determination of safe yield of underground reservoirs of the closed-basin type – transactions − american society of civil engineers, 78/1315, 148−218. mayer, d. (1996): zalihe pitkih voda u republici hrvatskoj [drinking water resources in the republic of croatia – in croatian].− rgn zbornik, 8, 27−35. miletić, p., urumović, k., capar, a., bošković, d. & mlakar, i. (1971): analiza mjerenja podzemnih voda nizvodno od virovitice – sr hrvatska [analysis of groundwater measurements downstream of virovitica – sr croatia – in croatian].− geol. vjesnik, 24, 155−159. ministry of environmental protection, physical plan ning and construction (2006): drugo, treće i četvrto nacionalno izvješće republike hrvatske prema okvirnoj konvenciji ujedinjenih naroda o promjeni klime [second, third and fourth national communication of the republic of croatia under the united nations framework convention on climate change − in croatian]. ministarstvo zaštite okoliša, prostornog uređenja i graditeljstva, zagreb, 96 p. rejman, w. (2007): eu water framework directive versus real needs of groundwater management.− water resources management, 21, 1363−1372. sophocleous, m. (2000): from safe yield to sustainable development of water resources – the kansas experience.− journal of hydrology, 235, 27−43. todd, d.k. (1959): ground water hydrology.− john wiley and sons. trninić, d. & bošnjak, t. (2008): protoci vode na savi kod zagreba [water discharges in the sava at zagreb – in croatian]. savjetovanje „zagrebačke vode“, kigen, zagreb, 27−39. urumović, k., hlevnjak, b., tadić, z. & petrović, m. (1994): zalihe podzemnih voda kvartarnog vodonosnika i mo gućnosti korištenja [groundwater resources of a quaternary aquifer and potential uses – in croatian].− znanstveni skup: “poljoprivreda i gospodarenje vodama”, bizovačke toplice, 425−433. water framework directive european union (wfd2000/60/ec) manuscript received march 22, 2010 revised manuscript accepted september 13, 2010 available online november 11, 2010 geol. croat. 49/2 1333 . 334 1 zagreb 1996 ahslrac! nole justifiability of the biostratigraphy explorations in petroleum geology kresimir krizmanic and vlasta premec fucek 1. introduction tn consequence of the ever demanding tasks which have been addressed to the oil industry concerning both efficiency or the exploration process and the empha­ s ised economy, the trend of neglecting fundamental geo logical disciplines, in which biostratigraphy belongs, has become obvious. petrolcllm geology discriminates against "classic" geological exp lorations in favour of seismic and well­ log methods because of the swiftness, ltialhcmatical exactness and economic saving. however, together with the undisputed qualities or geophysical techniques, it is ve ry often forgotten that such data, which are to be used in thc correlation ancimocielling of a given geolog­ ical object (depression, fi e ld), must be calibratcd with the data ga ined by petrographical, sed imentological, and also, biostratigraphical analyses and interpretations (lucic & krizmanic. 1993). therefore, sllch a short -term economic bcnefit, that has been achieved by not using biostratigraphy in the exploration process, is often later negated . 2. methods and goals of mostratigraphy research biostratigraphy as a science bloomed wi th the development of the oil industry. through deep drilling explorations, palacontologists obtain multiwdinous data on microfossil assemblages in the rock samples (cut ­ tings or cores). although such exploration in drill-holes is accompanied by many problems, there arc also some advantages. biostratigraphy is based on the recogn ition or species, definition or their geological ranges, and there­ fore determination of age. after estab li shing the strati ­ graphical borders and resolving the stra tigraphy in a few wells, the lateral extent of the subs urrace layers becomes known through well -to -well correlation. how­ ever, biostratigraphical data are more valid when utilised in conjunction with other related sciences (biolina -naftaplin. laboratory dept., lovinciceva i, hr-ioooo zagreb, croalia. proceedings ogy, ecology, radiometly, eustacy, magnetometry, etc.), to reconstruct a mosaic or gcological evenls. only three palaeontologica l disciplines utilised the most in the biostratigraphical research of the ina-na r­ taplin oil industry are mentioned herc. 2.1. macropalaeontology dispite the often very rare macrofossil occurence in boreho le materials particular mollusc genera and species which were considered to be outstandingly use­ ful in the correlation of sedi ments and oil and gas sa tu­ rated beds in paratethys can be traced. some well­ known index fo ssi ls (e.g. radix croat/ca, congeria banaficg, paradael/a abichi, conge ria r/iojilhoidea) were generally accepted as age indicators ror many years, with little additional consideration of their va li­ dity . 2.2. micropalaeontolog y microfossil assemblages of fo raminifera, osl racoda and silicoplacentina were analyzed from borehole rock samples. the appearance or species, slrat igraphic range, abundance, as well as the composition of whole bio­ coenoses have been closely examined. besides conven­ tional palaeontological literature, contributions rrom ina-naftaplin's bios tratigraphers arc also utilised as in a successive series of sediments phylogenetic lineages arc easily noted. a good example of these arc the clastic middle to upper eocene sediments in the northe rn adriatic, which contain fossils representing the com­ plete evolutionary lineage of the turborofa/ia ccrroazl/ ­ lensis group, as well as the species sllccession or the genus globigerillatheka (premec fucek. 1995; premec fucek et al.. in press). consequently, the lack of other index fossils in our latitude, proved thi s lineage to be advantageous in resolving biostratigraphic problems. 2.3. palynology due to the costs of maceration, s lide preparation and analys is, palynology is used mainly for sed im ents where there are no olher palaeontological data, e.g. sometimes the sediments are micropalaeontologicjly sterile , but palynologiealy ve ry rich. this is commonly :13-1 the case with uppcr tertiary sediments which are most often the most interesting for petroleum geology . in these homogenous sandstones it becomes feasible to determine stratigraphical and palaeoecological charac­ te ristics by using palynological biozonation (suto­ szentai, 1988). palaeontologists obtain information on palaeoenvi­ ronment through collecting data about the habitat (marine, brackish, freshwaler. .. ), mode of life (plank­ tonic, benthic ... ), climatic conditions (tropic, moder­ ate ... ), etc. morphology of the taxa, chemism, preserva­ tion and many other parameters are also ex tremely important. all observations arc compared with relevant lit e rature and if some new inrormation is obtained it is published . biostratigraphical and palaeoecological data are cnhanced with petrographical and sedimento logical rock characteristics, chemical analyses etc., so that all tile information on age, type or rock and depositional environment becomes known. sometimes the structural and tectoni cal rramcwork may also be defined. such a multidisc iplinary approach based on the results of the scientific investigation of many spccialists, is highly reliable and can be checked and compared with other scientific investigations. 3. iliostratlgraphical application in the oil industry in the contexl of industrial appl icability, biostratig­ raphy plays a unique role in resolving the multiplicity or geological problems which arise during the explo­ ration and exploitation activities of petroleum compa­ nies. 13y using chronostratigraphical and palaeoecologi­ cal data, accurate and detailed well -to-well correlation is made in order to facilitate the interpretation and pre­ diction or reservoirs. biostratigraphy is establi shed as one of th e main techniques used for this purpose because easily distingu ishable changes in the fossil record commonly occur with in sequences which appear uniform on lithologic and electric logs. structural traps for oil and gas ca n sometimes be si mply recognised llsing geophys ical techniques. however, a la rger prob­ lem is involved in the regional mapping of palaeogeo­ graph ic and env ironmental parameters which influence the st ra tigraphic control s of hydrocarbon distribution. the accuracy or these maps depends on the precision with which isochro nous surfaces can be identified (stainforth ct ai., 1975). exclusive usc or seismic, well log or lithostratigraphic data is a mistake, because rocks of physically similar composition at many points, commonly prove to be different in age. furthermore, in a sense or a new cconomy, the exchange of knowledge and information through con­ versation becomes more and more important in busi ­ ness. as each individual contributes personal ideas and geologia croatica 49(2 experience in group discussion amongst specialists with multifarious knowledge and a common aim, such ideas become refined by the group. they make a team, with­ out the coercion or initiative of superiors. the result or such teamwork is, because of enthusiastll, healthy cotll ­ petition, rivalry and a desire for new understanding, very often remarkabl e by its originality , lucidity , applicability and rapidity. direct saving and profit is shown, along with better efficiency, in improving hori ­ zontal and vertical communication as well as st imulat­ ing dynamism within the finn. the competitiveness of the company is also improved because on ly such agile, prompt, and dynamic systems are competitive. 4. instead conclusion 1 beg of vip cord possessors ij/ oil co li/poj/ies j/ot to liegieet tile ii/lldall/ellfal discipiil/ cs such ns biostrnlig­ rnplly and sedilllellfoiogy, cl7l1se withollt thelll there is j/g prosperous geology. dr. jean dercourt, president of the commission for the geological map of the world, excerpt of the oral presentation on 81b maegs , budapest, 1993. 5. references lucic, d. & krizmanic, k. (1993): laboralorijske tehnikc i metodika primjene rezultata tijekolll geo­ [oskog istrazivanja i razrade podzemlja. naftap lin, 1, 15-19, zagreb. premec fucek, v. (1995): biostratigraphy and planktonic foraminiferal lineages of the middle to late eocene succession in the north adriatic sea.­ first croat. geol. congr., opatija 18-21.10.1995., abstracts, 77, zagreb. premec fucek, v., bai3ic, lj., bajraktare­ vic, z. & gusic, i. (in pres s): planktonic foraminiferal biostratigraphy and paleoecology of the mjddle to upper eocene succession in the north adriatic sea. igcp-28 6, early pal eogene bentos, ljubljana. stain forth, r.m., lamb, j.l., luterbacher, h. , beard, j.h. & jefords , r.m. (1975): ceno­ zoic planktonic foraminiferal zonation and chanlc­ teristic of index forms.paleontological contribu­ tions , 62, the university of kansas, lawrence, 425p. suto-szentai, m. (1988): microplankton zones of organic skeleton in the pannonian s .1. stratum complex and in the upper par! of the sarmatian strata.acta bot. hungarica, 34/3-4, 339-356, budapes t. durn.indd terra rossa in the mediterranean region: parent materials, composition and origin goran durn 1. introduction thr red colour of many of the soils in the mediterranean region was the main reason that in the past the broad term “red mediterranean soils”, occasionally “terra rossa”, became quite a common indication for all soils in the region (yaalon, 1997). bresson (1993) stated that red mediterranean soils resulted from a bisiallitic type of weathering with the release of high amounts of iron oxides closely bound to clay minerals. according to fedoroff (1997), the bisiallitic type of weathering is not a specific characteristic of red mediterranean soils. he also stated that the concept of clay illuviation is not yet unanimously accepted as a leading soil forming process in red mediterranean soils. the colour of the b horizon in red mediterranean geologia croatica 56/1 83–100 23 figs. 6 tabs. zagreb 2003 key words: terra rossa, parent materials, composition, origin, mediterranean region. university of zagreb, faculty of mining, geology and petroleum engineering, pierottieva 6, hr-10000 zagreb, croatia; e-mail: gdurn@rgn.hr abstract in the past, the term “terra rossa” became quite a common indication for all limestone derived red soils in the mediterranean region. today, in some classification systems based on the mediterranean climate as the major soil differentiating criterion, the term terra rossa is used as a name for the soil subclass “modal fersiallitic red soil” when situated on limestones (duchaufour, 1982). however, several national soil classifications (e.g. croatian, italian, israeli) retained the term “terra rossa” for the hard limestone derived red soils. the nature and relationship of terra rossa to underlying carbonates is a long-standing problem which has resulted in different opinions with respect to the parent material and origin of terra rossa. terra rossa is a reddish clayey to silty-clay material, which covers limestone and dolomite in the form of a discontinuous layer ranging in thickness from a few centimetres to several metres. it is also found along cracks and between bedding surfaces of limestones and dolomites. thick accumulations of terra rossa like material are situated in karst depressions in the form of pedo-sedimentary complexes. a bright red colour is a diagnostic feature of terra rossa and is a result of the preferential formation of haematite over goethite, i.e. rubification. terra rossa can be considered as soil, vetusol, relict soil (non-buried-paleosol), paleosol or pedo-sedimentary complex (soil-sediments) among different authors. most authors today believe that terra rossa is polygenetic relict soil formed during the tertiary and/or hot and humid periods of the quaternary. however, some recent investigation in the atlantic coastal region of morocco (bronger & sedov, 2002) show that at least some terra rossa previously referred to as polygenetic relict soils should be regarded as vetusols. in some isolated karst terrain, terra rossa may have formed exclusively from the insoluble residue of limestone and dolomite but much more often it comprises a span of parent materials including, for example, aaeolian dust, volcanic material or sedimentary clastic rocks which were derived on carbonate terrain via different transport mechanisms. boero & schwertmann (1989) concluded that it is of little relevance for the process of rubification whether the primary fe sources are autochthonous or allochthonous as long as the general pedoenvironment remains essentially suitable for the formation of terra rossa. this pedoenvironment is characterised by an association of mediterranean climate, high internal drainage due to the karstic nature of a hard limestone and neutral ph conditions. terra rossa is formed as a result of: (1) decalcification, (2) rubification and (3) bisiallitization and/or monosiallitization. since fed/clay ratios are relatively uniform in most terra rossa, translocation of clay particles is responsible for the distribution of the red colour throughout the whole profile. however, since terra rossa soils have been exposed to various climatic fluctuations they can be affected by eluviation, yellowing and secondary hydromorphy. erosion and deposition processes which were superimposed on karst terrains and induced by climatic changes, tectonic movements and/or deforestation might be responsible for both the patchy distribution of terra rossa and thick colluvial or alluvial terra rossa accumulations in uvala and dolina type of karst depressions (pedo-sedimentary complexes, soil-sediments). soils has a hue redder then 5yr and a chroma higher than 3.5 (bech et al., 1997). although popular, this geographically based term was not recognized as a good term for a soil group in well defined soil-property controlled systems. delineation of the mediterranean region itself is not generally accepted. generally, the mediterranean region surrounds the mediterranean sea and extends between the latitudes 40 and 30ºn over an area of 4.300,000 km2 to 7.300,000 km2 if the drier areas in the near east are included (lehouerou, 1992). however, the mediterranean type of climate is not restricted to these latitudes (fig. 1). also, similar environmental conditions prevail in all the other continents, but to a lesser extent (yaalon, 1997). consequently, yaalon (1997) concluded that red mediterranean soils are no longer used as a separate classification group in modern soil taxonomies (soil taxonomy; fao system). in some classification systems based on the mediterranean climate as the major soil differentiating criterion, they are partally replaced with the term “fersialitic soils” (duchaufour, 1982). 84 geologia croatica 56/1 of a discontinuous layer ranging in thickness from a few centimetres to several metres. it is also found along more or less karstified cracks and between the bedding surfaces of limestones and dolomites. thick accumulations of terra rossa-like material are situated in karst depressions in the form of pedo-sedimentary colluvial complexes (durn et al., 1999). terra rossa can be covered by pliocene–pleistocene sediments of mainly carbonate composition (moresi & mongelli, 1988) or upper pleistocene loess (cremaschi, 1990a; durn et al., 1999). based on the approach, experience and background of authors (e.g. pedology, geology, geography, climatology) as well as field and laboratory methods used, terra rossa can be considered as soil, relict soil (non-buried-palaeosol), palaeosol or a pedo-sedimentary complex. some authors managed to find evidence that red soils are being created today (verheye & stoops, 1973) in areas with certain climatic characteristics (for example, lebanon). most authors today believe that terra rossa is a polygenetic relict soil formed during the tertiary and/or hot and humid periods of the quaternary (e.g. bronger & bruhn-lobin, 1997 and altay, 1997). however, some recent investigations (e.g. bronger & sedov, 2002) show that at least some terra rossa previously referred to as polygenetic relict soils should be regarded as vetusols (soils which are marked by a continuity of pedogenetic processes in time), in accordance with the concept of cremaschi (1987). however, the term “terra rossa” remained as a name for the soil subclass “modal fersiallitic red soil” when situated on limestones. several national soil classifications (e.g. croatian, italian, israeli) retained the term “terra rossa” for the hard limestone derived red soils (fig. 2). terra rossa is a reddish clayey to silty–clayey soil especially widespread in the mediterranean region, which covers limestone and dolomite in the form fig. 1 distribution of the mediterranean climate around the mediterranean and adriatic sea (modified from the times atlas of the world, 1989). fig. 2 distribution of terra rossa soils in croatia (from bogunović et al., 2000). (2) relationships between particle-size distribution in terra rossa and the insoluble residue of limestone and dolomite, (3) bulk and clay mineralogy in terra rossa and the insoluble residue of limestone and dolomite, and (4) possible parent materials other than the insoluble residue of limestone and dolomite, their recognition and significance. examples from istria will be used to demonstrate these aspects. istria is a typical example of the association between terra rossa and underlying limestones and dolomites. it belongs to the nw part of the adriatic carbonate platform. this part of the platform is composed of a succession of carbonate deposits more than 2000 m thick of middle jurassic (bathonian) to eocene age, and is overlain by palaeogene (eocene) foraminiferal limestones, transitional beds (globigerina marls) and flysch deposits (fig. 3). the most important geological structure of the istrian peninsula is the western istrian anticline (polšak & šikić, 1973; marinčić & matičec, 1991), as shown on fig. 3. according to velić et al. (1995) carbonate and flysch deposits of istria can be divided into four large-scale sequences. the 1st, 2nd and 3rd largescale sequences are composed of carbonates, each terminated by important, long-lasting emersions, i.e. type 1 sequence boundaries (tišljar et al., 1998). since the formation of flysch, the surface has been affected by tectonics, karst processes and weathering which has led to the development of both surficial and underground features. different types of sediments, polygenetic palaeosols and soils have been formed. the oldest quaternary sediments were discovered in the šandalja cave near pula and are represented by red breccia with faunal remains of early pleistocene age (malez, 1981). climatic and biotic factors have changed during the late tertiary and quaternary but the pedoenvironment on the hard carbonate rocks of the jurassic–cretaceous–palaeogene carbonate plain of southern and western istria generally remained suitable for rubification. terra rossa is found on the jurassic–cretaceous–palaeogene carbonate plain of southern and western istria (figs. 3 and 4). it fills cracks and sinkholes, and forms a discontinuous surface layer up to 2.5 metres thick which is, in places, covered by upper pleistocene loess. thick (up to 14 metres) accumulations of terra rossa-like material are found in karst depressions in the form of pedo-sedimentary colluvial complexes. 2. iron-oxide phases and total, na dithionite–citrate bicarbonate and ammonium oxalate extractable iron in terra rossa haematite and goethite are the main pedogenic ironoxide mineral phases in terra rossa (bronger et al., 1983; torrent & cabedo, 1986; boero & schwertmann, 1989; boero et al., 1992; durn in soil taxonomy (soil survey staff, 1975) terra rossa is classified as alfisols (haploxeralfs or rhodoxeralfs), ultisols, inceptisols (xerochrepts) and mollisols (argixerolls or haploxerolls). according to the fao system (fao, 1974) terra rossa is recognised as luvisols (chromic luvisols), phaeozems (haplic phaeozems or luvic phaeozems) and cambisols. the croatian classification puts terra rossa in the class of cambic soils (škorić, 1986). the nature and relationship of terra rossa to underlying carbonates is a long-standing problem which has resulted in different opinions with respect to the parent material and origin of terra rossa. the most widely accepted theory is that terra rossa has developed from the insoluble residue of carbonate rocks (tućan, 1912; kišpatić, 1912; kubiëna, 1953; marić, 1964; ćirić & aleksandrović, 1959; plaster & sherwood, 1971; škorić, 1979, 1987; bronger et al., 1983; moresi & mongelli, 1988). there are two different opinions among these authors. one is that the insoluble residue consists of materials belonging to pre-existing rubified soils, which dissipated and were sedimented as relics within the limestone (e.g. ćirić & aleksandrović, 1959). according to this opinion, the insoluble residue does not have to go through any mineralogical changes in order to create terra rossa. according to this, so called residual theory, the impact of climate on the development of terra rossa is not significant. its genesis, on the other hand, is significantly influenced by the mineral composition of the insoluble residue. accordingly, terra rossa belongs to the lithomorphic soils (bronger et al., 1983). this conclusion was drawn on the basis of similarities between the chemical and mineralogical composition of terra rossa and the insoluble residue. bronger & smolíková (1981) for example, failed to find any evidence regarding mineral depletion or clay mineral formation, and this led them to believe that terra rossa soils were lithomorphic as far as the residual theory was concerned. the alternative opinion is that terra rossa is not a lithomorphic soil but that the material (the insoluble residue) was subjected to intense weathering processes during dissolution of the carbonate rock (kubiëna, 1953; plaster & sherwood, 1971; moresi & mongelli, 1988). however, other authors have emphasised that the additions of external materials might have diminished the influence of the insoluble residue of limestones and dolomites as the primary parent material of terra rossa (lippi-boncampi et al., 1955; balagh & runge, 1970; yaalon & ganor, 1973; šinkovec, 1974; macleod, 1980; olson et al., 1980; jackson et al., 1982; danin et al., 1983; rapp, 1984; yaalon, 1997; durn et al, 1999). the main objective of this paper is to give an overview of terra rossa soils in the mediterranean region including the following aspects: (1) iron-oxide phases and distribution of fet, fed and feo in terra rossa, 85durn: terra rossa in the mediterranean region: parent materials, composition and origin 86 geologia croatica 56/1 organic matter, haematite can be considered an indicator of terra rossa formation (boero & schwertmann, 1989). based on analysis of 48 terra rossa samples from various locations around the world (italy, greece, israel, spain, lebanon, france, mexico, germany and australia) boero & schwertmann (1989) found that fed, fed/fet, haematite/goethite ratios and al substitution in haematite and goethite vary to a rather limited extent which may indicate the specific pedoenvironment under which terra rossa is formed. they suggested this pedoenvironment is characterised by an association of mediterranean climate, high internal drainage due to the karstic nature of a hard limestone and neutral ph conditions. xrd analysis showed that the clay fraction of terra rossa samples from istria contains both haematite and goethite (durn et al., 2001a; fig. 5). broadening of diagnostic haematite and goethite xrd peaks indicates the low degree of their crystallinity and their pedogenic origin. the munsell hue of dry terra rossa samples ranges between 5yr and 10r, which et al., 1999). the bright red colour is a diagnostic feature of terra rossa and is a result of the preferential formation of haematite over goethite, i.e. rubification. boero & schwertmann (1989). namely, in the 30 samples examined (<2 µm fraction) they also estimated that the haematite/(haematite+goethite) ratios averaged 0.62±0.055 i.e. the content of haematite is higher than the content of goethite in terra rossa. singer et al. (1998) interpreted the difference in iron oxide mineralogy between terra rossa (dominated by haematite) and rendzina (dominated by goethite) developed on limestones in israel as a consequence of soil climate, specifically the moisture regime of the two soils. the role of well-lithified limestones below terra rossa in maintaining a haematitic pedoenvironment was also stressed by boero et al. (1992). they found that the occurrence of haematite in terra rossa in italy is irrespective of climate, and haematite may be the dominant iron oxide even in sites with 13ºc aat and up to 1700 mm aap. since in situ formation of haematite reflects a relatively low water activity, high temperature, good aeration and/or high turnover rate of fig. 3 map showing schematic distribution of megasequences in istria and location of the western istrian anticline (partly modified after velić et al., 1995). 87durn: terra rossa in the mediterranean region: parent materials, composition and origin (table 1) point to the low content of poorly crystalline fe-oxides (e.g. ferrihydrite). relatively uniform fed/fet ratios are also shown by the high positive correlation coefficient (fig. 6) and point to a clear relationship between fed and fet in terra rossa. fed/clay ratios are relatively uniform (fig. 7) and clearly indicate a predominance of co-illuviation of clay and fe oxides, i.e. the connection of fe-oxides with the clay fraction. the rather limited variation of selected fe-oxide characteristics in 40 terra rossa samples from istria (table 1; especially the average and 95% c.i. values of fed and fed/fet) are very similar to those of boero & schwertmann (1989). while fed in 45 terra rossa samples averaged 3.5% (±0.3) (boero & schwertmann 1989), in 40 samples from istria, fed averaged 3.68% (±0.28). the arithmetic means of the two sets of data are not significantly different at the 0.05 level (t-test). the two populations are indistinguishable at the 0.05 level, i.e. two arithmetic means represent two independent estimates of the same population (fed in terra rossa). this supports boero & schwertmann’s (1989) conclusion, that the rather limited extent of variation of selected fe-oxide characteristics may indicate a specific pedoenvironment in which terra rossa is formed. 3. relationships between particle-size distribution in terra rossa and the insoluble residue of limestone and dolomite it is generally accepted that terra rossa is formed on hard and permeable limestones and dolomites with a very low content of insoluble residue (yaalon & ganor, 1973; macleod, 1980; danin et al., 1983; moressi & mongelli, 1988; yaalon, 1997). however, neither the insoluble residue content of limestone and dolomite nor its particle size distribution is always compatible with the development of terra indicates that red haematite masks the yellow colour of goethite. ferrihydrite (which also gives a red colour to soil) was not detected with xrd, probably due to its small amount and poor crystallinity. the results of the analysis of fet (total iron), fed (iron extractable with na dithionite–citrate bicarbonate) and feo (iron extractable with ammonium oxalate) in samples of terra rossa from istria are presented in table 1. the mean value of the fed/fet ratio, which is taken as an index of weathering (e.g. arduino et al., 1984; boero & schwertmann, 1987; bech et al., 1997) is 0.7, and reflects a quite high degree of weathering of fe-containing primary silicates. low values of feo fig. 5 characteristic parts of the xrd patterns of terra rossa sample 1 (<2 μm fraction). a) air dried; b) treated with hcl (1:1, 24h). legend: kl) kaolinite; i) illitic material; q) quartz; h) haematite; g) goethite (taken from durn et al., 2001). fig. 4 distribution of terra rossa in istria (modified after škorić, 1987). legend: 1) terra rossa, calcocambiosol, eutric cambiosol, rigosol from terra rossa (area of terra rossa >70%); 2) terra rossa, calcocambiosol, eutric cambiosol (area of terra rossa is 50–70%); 3) eutric cambisol on loess, luvisol on loess, rigosol from luvic and eutric cambiosol (40:30:30). n x s cv(%) 0.95 c.i. fet 40 5.19 0.99 19.07 4.88–5.51 fed 40 3.68 0.89 24.18 3.40–3.96 feo 40 0.39 0.09 23.08 0.36–0.42 fed/fet 40 0.70 0.07 10.00 0.68–0.72 feo/fed 40 0.112 0.033 29.46 0.102–0.122 table 1 basic statistics for total, dithionite and oxalate extractable iron (%) in terra rossa samples (<2 mm). legend: n = number of samples, x = arithmetic mean, s = standard deviation, cv(%) = coefficient of variation, 0.95 c.i. = confidence interval (taken from durn et al., 2001). 88 geologia croatica 56/1 residue of limestones and dolomites as the primary parent material of terra rossa. according to durn et al. (1999) terra rossa in istria is composed predominantly of clay (<2 µm) and silt (2–63 µm) sized particles, with sand (>63 µm) particles forming less than 4% (fig. 8). the clay content ranges from 32.1 to 77.2% and generally increases with depth in the profiles. the higher content of sand sized particles observed in a few samples is attributed to rhizoconcretions which formed in terra rossa as the result of palaeopedological processes which post-date terra rossa formation (recalcification of terra rossa following its burial) or to the recent colluvial additions of flysch. the insoluble residue content of the underlying limestones and dolomites ranges from 0.08 to 2.23 wt.% and is dominated by clay sized particles (durn et al., 1999). the clay content in the insoluble residues ranges from 63.8 to 87.5%. an average silt/ clay ratio in terra rossa (0.81) is higher than that in the insoluble residue of limestone and dolomite (0.25). if terra rossa has developed only from the insoluble rossa entirely by the dissolution of carbonate rock. the average insoluble residue content of limestones in epirus, greece was found to be 0.15% (macleod, 1980). according to danin et al. (1983) dolomites near jerusalem, israel contain on average 1% insoluble residue. the insoluble residue content of limestone and dolomite from istria, croatia, averages 0.86% (durn et al., 1999). based on: (1) a conservative mean content of 1% of insoluble limestone residue, (2) the annual rate of dissolution of 10 to 40 µm limestone and (3) a high extent of preservation of residue (not counting any loss by corrosion), yaalon (1997) concluded that it would be necessary to dissolve 50 m of limestone to accumulate half a metre of soil, which would require some 2.000,000 years (±50%). higher silt/clay ratios in terra rossa compared to the insoluble residue of underlying limestones and dolomites was observed in israel (yaalon & ganor, 1973), greece (macleod, 1980) and croatia (durn et al., 1999) which indicates that the additions of external materials might have diminished the influence of the insoluble fig. 6 the ratio of dithionite soluble iron (fed) and total iron (fet) in terra rossa. r is significant at level p<0.01 (taken from durn et al., 2001). fig. 7 the ratio of the amount of clay fraction (<2 μm) and dithionite soluble iron (fed) in terra rossa; r is significant at level p<0.01 (taken from durn et al., 2001). 89durn: terra rossa in the mediterranean region: parent materials, composition and origin residue of limestone or dolomite, its clay content, due to weathering, should be higher than that in the insoluble residues which is not the case, which supports the influence of external material in the genesis of terra rossa in istria. 4. bulk and clay mineralogy in terra rossa and insoluble residue of limestone and dolomite the mineral composition of terra rossa in the mediterranean area may be very variable. macleod (1980) found that the clay fraction of terra rossa from epirus (greece) consists of kaolinite, micaceous minerals, vermiculite, quartz and fe-oxides. according to moresi & mongelli (1988) terra rossa from apulia (italy) is composed of kaolinite, illite, fe-oxides, quartz, feldspar, mica, al-oxides and hydroxides, and ti-oxides. the clay fraction of terra rossa from spain contains kaolinite, illite, vermiculite, montmorillonite, interstratified clay minerals and goethite (garciagonzales & recio, 1988). the chief constituents of the clay fraction of terra rossa from sardinia are illite and kaolinite, while hydroxy-interlayered vermiculite is the dominant phase in ne italy (boero et al., 1992). terra rossa soils from the karbum peninsula of izmir province (turkey) contain a clay fraction comprising smectite, palygorskite, kaolinite, fe-oxides and quartz (atalay, 1997). bronger & bruhn-lobin (1997) found considerable to extensive formation of clay minerals, mainly kaolinites in terra rossa from nw morocco. data on the mineral composition of the insoluble residue of limestone and dolomite are quite scarce in the region. insoluble residues of limestones from epirus (greece) are dominated by micaceous clay minerals while quartz and kaolinite are sporadically present in the clay fraction and of local importance (macleod, 1980). moresi & mongelli (1988) stated that the insoluble residue of cretaceous carbonate rocks from the murge and salento areas (italy) is composed of kaolinite, illite, fe-oxides, quartz, feldspar, mica, aloxides and hydroxides, and ti-oxides. terra rossa soils situated on those carbonate rocks consist of the same minerals, but the amount of kaolinite is higher than the illite content. in general, the bulk and clay mineralogy in terra rossa and the insoluble residue of underlying limestone and dolomite indicate that: (1) terra rossa formed from re-working of the insoluble residue of underlying carbonate rocks (e.g. moresi & mongelli, 1988) or (2) the additions of external materials may have diminished the influence of the insoluble residue of limestones and dolomites as the primary parent material of terra rossa (e.g. macleod, 1980). istrian terra rossa is composed of quartz, plagioclase, k-feldspar, micaceous clay minerals (illitic material and mica), kaolinites (kld and kl), chlorite, vermiculite, low-charge-vermiculite or high-charge smectite, mixed-layer clay minerals (other than illitic material), haematite, goethite and an xrd-amorphous inorganic compound (durn et al, 1999). calcite, dolomite and boehmite are sporadically present and are of local importance. the results of semiquantitative phase analysis of selected terra rossa samples are given in table 2. dominant mineral phases in the clay fraction of all terra rossa from istria are kaolinites (kld and kl), illitic material, fe-oxides and xrd amorphous inorganic compounds, while vermiculite, low-charge-vermiculite or high-charge smectite, chlorite, mixed-layer clay minerals and quartz are present in subordinate amounts (fig. 9). the clay fraction of terra rossa also contains boehmite (only those samples which were taken in the vicinity of bauxites of jurassic and palaeogene age). the results of xrd analysis of the clay fraction separated from selected terra rossa samples are presented in table 3. in all terra rossa samples the content of kaolinite which does not form intercalation compounds with dmso (kl) is higher than that of kaolinite which intercalates with dmso (kld). fine clay (<0.2 µm fraction) contains only kaolinite which does not form intercalation compounds with dmso (kl) (table 4). this mineral is the dominant mineral phase in fine clay. coarse and medium clay (2–0.2 µm fraction) contains both kaolinite which does not form intercalation compounds with dmso (kl) and kaolinite which intercalates with dmso (kld), the former being more abundant (table 4). low-charge vermiculite or highcharge smectite was detected only in the fine clay of samples 47 and 52 (table 4). the insoluble residues of limestone and dolomite are greyish-brown in colour and contain quartz, fig. 8 particle size analysis of terra rossa (taken from durn et al., 1999). 90 geologia croatica 56/1 clastic sedimentary rocks, transported and deposited on pediments cut into lower lying limestone. lippiboncampi et al. (1955) and yaalon & ganor (1973) mention the role of aeolian materials from volcanoes in the surrounding area in the formation of terra rossa. chiesa et al. (1990) concluded that in the marche region (italy), aeolian deposits formed during the pleistocene were affected by pyroclastic materials from the tyrrenian area. šušnjara et al. (1994) found vitric tuff interstratified within terra rossa near gljev in central dalmatia (croatia). rapp (1984) suggested that the terra rossa soils of southern europe might be wind-borne material from africa. according to jahn et al. (1991), 10% of the soil material in terra rossa from southernmost portugal is of aeolian origin. aeolian contributions have also been recognised due to the similarities in clay mineralogy (balagh & runge, 1970), similarities in heavy mineral fraction (šinkovec, 1974; durn et al., 1992; durn & aljinović, 1995), particle size distribution (macleod, 1980) and the divergence of oxygen isotopic ratios of associated fine quartz (jackson et al., 1982; nihlen & olsson, 1995). given the fact that the “cryptogamic imprint” on the rocks micaceous clay minerals (illitic material and mica), mixed-layer clay minerals, goethite and amorphous organic and inorganic compounds (durn et al., 1999). k-feldspar, plagioclase, and kaolinite which forms intercalation compounds with dmso and chlorite occur sporadically. the dominant mineral phase of the clay fraction of the insoluble residues is illitic material. the results of semiquantitative phase analysis of selected insoluble residues are shown in table 5. the results of xrd analysis of the related clay fraction, based on the patterns of oriented samples, are given in table 6. the bulk and clay mineral assemblage in the insoluble residue of limestones and dolomites does not support development of terra rossa entirely by the dissolution of carbonate rock. 5. possible parent materials other than insoluble residue of limestone and dolomite, their recognition and significance soil geomorphic studies made by olson et al. (1980) in southern indiana, usa, indicate that the terra rossa is mainly debris, derived from the erosion of higher lying sample quartz plagioclase k-feldspar hematite+goethite phyllos.+am. calcite dolomite boehmite 15 23 2 1 6 68 22 33 5 2 3 57 25 21 2 1 6 70 47 32 4 1 3 52 5 3 52 29 1 1 5 64 60 18 3 1 7 62 9 100 13 2 8 67 10 131 25 3 1 5 66 136 15 1 1 7 76 table 2 mineral composition of the <2 mm fraction of terra rossa (wt.%). legend: phyllos.+am. = phyllosilicates and amorphous inorganic compound (taken from durn et al., 1999). sample illitic material kld kl vermiculite l.c. vermiculite chlorite mc quartz boehmite 15 + + + + + + 22 + + + + + ch/v + 25 + + + + + + 47 + + + + x + + + 52 + + + + x + + + 60 + + + + + + + + 100 + + + + + + + + 131 + + + + + + 136 + + + + + + table 3 mineral composition of the < 2μm fraction of terra rossa after the removal of carbonates, humic materials and iron-oxides. legend: kld = kaolinite which forms intercalation compounds with dmso, kl = kaolinite which does not intercalate with dmso, l.c. vermiculite = low-charge vermiculite or high-charge smectite, mc = mixed-layer clay mineral, ch/v = chlorite/vermiculite, x = mineral present only in the <0.2 μm fraction (taken from durn et al., 1999). 91durn: terra rossa in the mediterranean region: parent materials, composition and origin (durn et al., 1999). for example, yaalon (1997) concluded that practically all terrestrial soils in the mediterranean region were influenced by the addition of aeolian dust. four different aspects regarding the parent material of terra rossa in istria will be presented: (1) particle size, (2) mineralogy, (3) geochemistry and (4) micromorphology. 5.1. particle size the insoluble residue content of limestone and dolomite from istria, croatia averages 0.86% (durn et al., 1999). the content of the insoluble residue indicates that an excessive thickness of limestone and dolomite must have been dissolved to form terra rossa, and that the extent of the preservation of that residue through the quaternary must have been unusually high. also, the average silt/clay ratio in terra rossa (0.81) is higher than that in the insoluble residue of limestone and dolomite (0.25) which indicates that coarser material must have contributed as parent material for terra rossa. when we compare the particle size of the insoluble residue of limestone and dolomite, loess and marl (fig. 10) with that of terra rossa (fig. 8), it does not exclude loess and flysch as possible parent materials for terra rossa formation. namely, both the insoluble residues of loess and marl are enriched in the silt and sand size fractions compared to the insoluble residue of limestone and dolomite. 5.2. mineralogy the bulk and clay mineral assemblage in the insoluble residue of limestones and dolomites also does not support development of terra rossa in istria entirely by can be detected on the rock faces under the present soil surface, danin et al. (1983) concluded that the principal contributor to the formation of the upper soil layer of terra rossa in the studied area in israel is from an aeolian source. previous statements imply a polygenetic nature for terra rossa. in some isolated karst terrains it may have formed exclusively from the insoluble residue of limestone and dolomite but much more often it comprises a span of parent materials which arrived on the carbonate terrain via different transport mechanisms fig. 9 characteristic parts of the xrd patterns of terra rossa sample 52 (<2 μm fraction) after removal of fe-oxides (oriented preparations): a) mg-saturated; b) k-saturated; c) k-saturated and dmso solvated; d) heated for 1 hour at 550°c. legend: v) vermiculite; mc) mixed-layer clay mineral; i) illitic material; kld) kaolinite which intercalates with dmso; kl) kaolinite which does not intercalate with dmso; q) quartz (taken from durn et al., 1999). sample illitic material kld kl vermiculite l.c. vermiculite chlorite mc boehmite <0.2 μm 15 25 75 tr. + 22 45 55 tr. + 25 30 70 tr. + 47 23 63 tr. 14 + 52 10 77 tr. 13 + 60 32 60 8 tr. + + 100 15 81 4 tr. + + 131 22 78 tr. + 136 19 78 3 + 2 – 0.2 μm 25 44 12 35 9 + + 52 50 12 33 5 tr. + + table 4 semiquantitative clay mineral composition of the <0.2 μm and 2–0.2 μm fractions of terra rossa after the removal of carbonates, humic materials and iron-oxides. legend: kld = kaolinite which forms intercalation compounds with dmso, kl = kaolinite which does not intercalate with dmso, l.c. vermiculite = low-charge vermiculite or high-charge smectite, mc = mixed-layer clay mineral, ch/v = chlorite/ vermiculite, illitic material+kld+kl+vermiculite+l.c. vermiculite+chlorite = 100 wt.% (taken from durn et al., 1999). 92 geologia croatica 56/1 the dissolution of carbonate rock. the dominant mineral phase in the insoluble residues is illitic material, and kaolinite which forms intercalation compounds with dmso was detected only in three samples (17, 75 and 79). plagioclase was only found in one sample (17) while all terra rossa samples contain this mineral (table 2). the insoluble residues do not contain vermiculite which was observed in small amounts in the clay fraction of all terra rossa samples. vermiculite is an unstable mineral in the pedogenic environment (barnhisel & bertsch, 1989; douglas, 1989). boero et al. (1992) suggest formation of hydroxy-interlayered vermiculite at the expense of 2:1 silicates in terra rossa of the moist environment of ne italy. we postulate that the appearance of vermiculite sample illitic material kld kl vermiculite l.c. vermiculite chlorite smectite mc quartz limestone and dolomite 56 + + ch/v + 63 + + + 75 + + + + 79 + + + + 85 + + + 130 + + + marl 94 + + + + + loess 48 + + + + x + ch/v + <0.2 μm 29 36 tr. 35 tr. + 2–0.2 μm 53 10 12 9 16 ch/v table 6 mineral composition of the < 2μm fraction of insoluble residues of limestone and dolomite, marl and loess after the removal of humic materials and iron oxides. semiquantitative clay mineral composition of the <0.2 μm and 2–0.2 μm fractions of loess sample 48 are also presented. legend: kld = kaolinite which forms intercalation compounds with dmso, kl = kaolinite which does not intercalate with dmso, l.c. vermiculite = low-charge vermiculite or high-charge smectite, mc = mixed-layer clay mineral, ch/v = chlorite/vermiculite, x = mineral present only in the <0.2 μm fraction, + = identified mineral. illitic material+kld+ kl+vermiculite+l.c. vermiculite+chlorite = 100 wt.% (taken from durn et al., 1999). sample quartz plagioclase k-feldspar goethite phyllos.+am. calcite dolomite i.r. of limestone and dolomite 56 6 6 4 84 63 8 6 4 82 75 14 2 6 78 79 15 4 80 85 8 4 88 130 17 4 2 77 marl 94 15 2 36 47 loess 48 17 4 1 1 31 21 25 table 5 mineral composition of insoluble residues of limestone and dolomite and mineral composition of bulk samples of marl and loess (wt.%). legend: phyllos.+am. = phyllosilicates and amorphous inorganic compound (taken from durn et al., 1999). in terra rossa from istria can be related to some parent material other than the insoluble residue of limestone and dolomite. low-charge vermiculite or high-charge smectite was detected in the <0.2 µm fraction of terra rossa samples which are situated below (47) or near (52) upper pleistocene loess (table 4, fig. 3). the presence of this mineral in those samples may indicate its aeolian origin because it was detected as one of the main mineral phases in the fine clay of the upper pleistocene loess in savudrija (table 6). the upper pleistocene loess post-dated terra rossa formation, but it indicates that during terra rossa formation, similar external materials might have contributed to terra rossa. this is especially important when we bear in mind that since the early middle pleistocene, loess deposition affected istria 93durn: terra rossa in the mediterranean region: parent materials, composition and origin relatively immobile in soil environments and suitable for geochemical “fingerprinting” (muhs et al., 1987; muhs et al., 1990), and elements with low ionic potential which are considered relatively mobile in soil environments. we chose the elements ti, nb and zr from the first group and na and k from the second group. the reason for taking the latter into consideration is the direct relationships of these elements to plagioclase (na), and micaceous clay minerals (illitic material and mica) and k-feldspar (k). (na2o/k2o)x100 ratios in the insoluble residue of limestones and dolomites ranges from 2 to 4.3 and are much lower than ratios in terra rossa, loess and marl (fig. 11). this, together with the results of bulk mineralogy (tables 2 and 5) indicates that terra rossa, loess and marl are enriched in plagioclase compared to the insoluble residue of limestones and dolomites. zr/nb ratios in the insoluble residue of limestones and dolomites are also significantly lower than these ratios in loess, marl and the majority of terra rossa samples (fig. 12). this is also partly valid for (zr/ti)x1000 ratios although there is obvious overlapping of the mondolaco profile and the lower part of the novigrad profile with the insoluble residue field (fig. 13). geochemical ratios also support the influence of external material in the genesis of terra rossa (figs. 11, 12 and 13). if we consider that zr, nb, and ti are relatively immobile in soil, than parent materials other than the insoluble residue of limestones and dolomites may have influenced the composition of terra rossa. rare earth elements (ree) are often used as indicators of geological processes and for provenance determination in clastic sediments (cullers et al., 1988). ree patterns in the clay fraction of sediments are quite similar to those of their source rocks (condie, 1991). ree in the sand-size fractions of soils derived from particular parent rocks may also vary significantly, reflecting the ree distribution of the parent rocks (cullers et al., 1988). however, the mobility and fractionation of ree during weathering and the dalmatian archipelago (cremaschi, 1990b). this is also supported by the characteristic heavy mineral assemblage in terra rossa, which in most terra rossa samples strongly resembles that of loess derived from the deflation of the po plain sediments during the middle and late pleistocene (durn, 1996; durn & aljinović, 1995). the heavy mineral fraction of these terra rossa samples is enriched in epidote–zoisite group minerals and amphiboles. the influence of the po plain provenance heavy mineral assemblage is substantial even in terra rossa samples with evidently higher content of zircon, tourmaline and rutile. 5.3. geochemistry in order to chemically characterize insoluble residues of carbonate rocks and compare them with terra rossa, marl and loess, durn et al. (1999) used elements with a high ionic potential which are considered fig. 10 particle size analysis of: 1) the insoluble residues of the jurassic and cretaceous limestones and dolomites; 2) loess; 3) marl (taken from durn et al., 1999). fig. 11 molar ratios of (na2o/k2o) x100 in terra rossa, loess and marl (from flysch sediments). two horizontal lines represent minimum and maximum values for this ratio in the insoluble residues of the jurassic and cretaceous limestones and dolomites (taken from durn et al., 1999). 94 geologia croatica 56/1 5.4. micromorphology the hierarchy of textural features in terra rossa from istria is not yet fully investigated but micromorphological investigations performed so far clearly point to its polygenetic origin. a terra rossa profile near medulin which represents a stagni chromic luvisol (according to wrb, 1994) can be used as an example. dissolution voids and cracks in limestone at the contact with terra rossa are infilled exclusively with clayey material (fig. 17). this clayey material represents either the fine material of the groundmass (micromass) or clay coatings and/or infillings. the bt horizon of the terra rossa has a vuggy–cracked microstructure (fig. 18). the main coarse basic mineral component is subangular to angular quartz, the size and shape of which, in general does not match that of quartz in the insoluble residue of the underlying limestone. mica and plagioclase are minor components while epidote and amphibole are very rare. rounded bauxite and limestone fragments are also very rare and up to 5 mm in diameter (figs. 19 and 20). in the bt horizon sub-rounded to rounded fragments of pedorelics (soil clasts and fragments of clay coatings) up to 2 mm in diameter can be found (fig. 21). their distribution in is also well documented (e.g. land et al., 1999). the total ree content of the <2 mm fraction of terra rossa samples from istria is quite variable and ranges from 104.09 to 394.95 ppm (durn et al., 2001b; fig. 14). chondrite-normalized ree patterns for all analysed samples (fraction <2 mm) show similar patterns to that of es. chondrite-normalized ree patterns of the <2 µm fraction of terra rossa are shown on fig. 15 and of the <2 µm fraction of i.r. of loess, flysch and limestone on fig. 16. durn et al. (2001b) concluded that the wide range of total ree contents in bulk samples, the difference in lree/hree ratios in different grain size fractions and the observed significant positive ce-anomaly are in favour of a polygenetic origin of terra rossa in istria. the difference in ree distribution can be attributed to the ree content of both parent carbonate rocks and different external materials which have contributed to the genesis of terra rossa (loess, flysch, bauxite), modified by weathering process which characterise specific pedoenvironments in which terra rossa is formed. fig. 13 ratios of (zr/ti)x1000 in terra rossa, loess and marl (from flysch sediments). two horizontal lines represent minimum and maximum values for this ratio in the insoluble residues of the jurassic and cretaceous limestones and dolomites (taken from durn et al., 1999). fig. 12 ratios of zr/nb in terra rossa, loess and marl (from flysch sediments). two horizontal lines represent minimum and maximum values for this ratio in the insoluble residues of the jurassic and cretaceous limestones and dolomites (taken from durn et al., 1999). 95durn: terra rossa in the mediterranean region: parent materials, composition and origin shape of the quartz grains supports a polygenetic history of terra rossa soil. a pedo-sedimentary complex of terra rosa like material in sjenokoša gives another good example of the complex history of this polygenetic soil (durn et al., 2003). 6. discussion and conclusions terra rossa is a reddish clayey to silty–clayey soil especially widespread in the mediterranean region, which covers limestone and dolomite. the bright red colour is a diagnostic feature of terra rossa and is a result of the preferential formation of haematite over goethite, i.e. rubification. terra rossa has slightly alkaline to neutral ph and an almost completely satuthe bt horizon is partly clustered. however they are more abundant in the lower part than in the upper part of the bt horizon. some of them are structurally very similar to clay features observed in dissolution voids and cracks in the limestone. although some of them can be regarded as papules (they are the result of repeated swelling and shrinking when broken clay coatings are incorporated into the groundmass) or a product of bioturbation, they can also be interpreted as a result of intense soil erosion. textural pedofeatures present are microlaminated and laminated reddish and yellow clay coatings along planar voids, channels, vugs and vesicles and microlaminated clay and silt infillings of channels (figs. 22 and 23). the presence of pedorelics, epidote, amphibole, bauxite and limestone fragments as well as the size and fig. 14 box & whisker diagram for the total content of ree in terra rossa, flysch, loess and insoluble residues of the jurassic and cretaceous limestones. fig. 15 chondrite normalized ree patterns of the <2 μm fraction of terra rossa. 97durn: terra rossa in the mediterranean region: parent materials, composition and origin96 geologia croatica 56/1 according to gvirtzman & wieder (2001), red mediterranean soils situated in the coastal plain of israel developed during the last glacial stage, from 40 to 12.5 ka. some recent investigations in the atlantic coastal region of morocco (bronger & sedov, 2002) show that at least some terra rossa, previously referred to as polygenetic relict soils, should be regarded as vetusols (soils which are marked by a continuity of pedogenetic processes in time), in accordance with the concept of cremaschi (1987). namely, they concluded that soil formation processes were constant during terra rossa formation due to slight climatic fluctuations through the brunhes epoch and the holocene in the region. in some isolated karst terrains terra rossa may have formed exclusively from the insoluble residue of limestone and dolomite, but it more frequently comprises a span of parent materials including, for example, aeolian dust, volcanic material or sedimentary clastic rocks which arrived on the carbonate terrain via different transport mechanisms. yaalon (1997) rated base complex (dominated by calcium and/or magnesium). in some classification systems based on the mediterranean climate as the major soil differentiating criterion, the term terra rossa is used as a name for the soil subclass “modal fersiallitic red soil” when situated on limestones. (duchaufour, 1982). several national soil classifications (e.g. croatian, italian, israeli) retained the term “terra rossa” for the hard limestone derived red soils. terra rossa can be, among different authors, considered soil, vetusol, relict soil (non-buried-palaeosol), palaeosol or a pedosedimentary complex. most authors today believe that terra rossa is a polygenetic relict soil formed during the tertiary and/or hot and humid periods of the quaternary (e.g. bronger & bruhn-lobin, 1997; altay, 1997; durn et al., 1999). for example, bronger & bruhn-lobin (1997) concluded that terra rossa situated on quaternary calcarenites in nw morocco is probably of mid-pleistocene age. namely its formation extended over most parts of the brunhes epoch, including those of the cool (glacial) stages. fig. 16 chondrite normalized ree patterns of the <2 μm fraction of insoluble residues of flysch, loess and the cretaceous limestone. fig. 17 dissolution voids and cracks in limestone infilled with terra rossa. medulin profile. plain polarized light. length of photo – 7.5 mm. fig. 18 vuggy/cracked microstructure. dominant voids are vugs and cracks. vesicles and channels also occur. most voids with fe-oxide stained clay coatings. iron depletion pedofeatures around open voids are also present (lower part of photo). medulin profile. 35–43 cm, bt horizon. plain polarized light. length of photo – 7.5 mm. 97durn: terra rossa in the mediterranean region: parent materials, composition and origin concluded that practically all terrestrial soils in the mediterranean region might have been influenced by the addition of aeolian dust in the last 5 my when the sahara became a desert. he states that values of up to 50% of aeolian material in hard limestone derived soils are highly reasonable. evidence of aeolian dust from the sahara were found in in terra rossa in morocco, israel, turkey, spain, greece, portugal and italy (e.g. bronger & bruhn-lobin, 1997; yaalon & ganor, 1973; danin et al., 1983; altay, 1997; macleod, 1980; rapp, 1984; nihlen & olsson, 1995; jahn et al., 1991; jackson et al., 1982). according to nihlen & olsson (1995) the mean annual deposition of dust from the sahara in the southern aegean area (greece), varies from 11.2 to 36.5 g/m2. he concluded that assuming constant deposition rates, the estimated thickness of a dust layer built up over a time span of 1000 years would be in the range of 7–21 mm. at this rate of accumulation the accreted dust manages to become completely assimilated by the prevailing pedoenvironment and is leached or bioturbated into the soil profile (yaalon, 1997). this is why the addition of aeolian dust to a soil is usually difficult to identify. when the rate of accumulation increases to 40 µm/y, dust accumulates as surface loess (yaalon, 1997). this is especially important when we bear in mind that since the early middle pleistocene, loess deposition affected istria and the dalmatian archipelago (cremaschi, 1990b). in istria, the upper pleistocene loess post-dated terra rossa formation. (durn et al., 1999) found that both loess older than that of the upper pleistocene age, and flysch may have contributed to the genesis of terra rossa in istria. chiesa et al. (1990) concluded that in the marche region (italy), aeolian deposits formed during the pleistocene were affected by pyroclastic materials from the tyrrenian area. this may imply that terra rossa soils in that region may also contain material of that parentage. lippi-boncampi et al. (1955) and yaalon & ganor (1973) mention the role of aeolian materials from volcanoes in the surrounding fig. 19 part of a bauxite fragment in terra rossa. medulin profile. 60–68 cm, bt horizon. plain polarized light. length of photo – 7.5 mm. fig. 20 fragment of limestone in terra rossa and voluminous feoxide stained clay coatings. fragment of limestone is largely coated with clay. medulin profile. 60–68 cm, bt horizon. +n. length of photo – 3.3 mm. fig. 21 fragments of clay coatings and microlaminated clay coatings in terra rossa. medulin profile. 60–68 cm, bt horizon. plain polarized light. length of photo – 7.5 mm. fig. 22 fe-oxide stained complex voluminous microlaminated clay coatings with sharp extinction zones. medulin profile. 35–43 cm, bt horizon. plain polarized light. length of photo – 1 mm. 98 geologia croatica 56/1 99durn: terra rossa in the mediterranean region: parent materials, composition and origin area, in the formation of terra rossa while šušnjara et al. (1994) found vitric tuff interstratified within terra rossa near gljev in the central part of dalmatia (croatia). detailed research on two palaeosols, of late pleistocene (pedomarker a) and holocene (pedomarker b) age, in the carbonate apennine range of central italy, showed that they developed from air-fall pyroclastic material (frezzotti & narcisi, 1996). according to some ongoing studies, deposition of pyroclastic volcanic material, which was a recurrent process through the quaternary in the adriatic region, may have significantly affected soils in the region (b. lugović, personal communication). boero & schwertmann (1989) concluded that it is of little relevance for the process of rubification whether the primary fe sources are autochthonous or allochthonous as long as the general pedoenvironment remains essentially suitable for the formation of terra rossa. they suggested this pedoenvironment is characterised by an association of mediterranean climate, high internal drainage due to the karstic nature of a hard limestone and neutral ph conditions. terra rossa is well drained because it is well aggregated (high exchangeable ca and mg content) and situated on highly permeable carbonate rocks (torrent, 1995). it is formed as a result of: (1) decalcification, (2) rubification and (3) bisiallitization and/or monosiallitization. the bisiallitic type of weathering is not a specific characteristic of red mediterranean soils (fedoroff, 1997). kaolinites were found as the main pedogenic clay mineral phases in terra rossa from istria, croatia (durn, 1996; durn et al., 1999) and nw morocco (bronger & bruhn-lobin, 1997; bronger & sedov, 2002). this may imply that the type of weathering in terra rossa, and the resulting authigenic clay mineral phases, depends on the time of formation, climate and parent materials. for example, boero et al. (1992) found that illite and kaolinite are the main clay mineral phases in terra rossa from xeric sites while al-interlayered vermiculite occurred in cool, moist sites. the concept of clay illuviation is not yet unanimously accepted as a leading soil forming process in red mediterranean soils (fedoroff, 1997). illuviated clays usually coat and infill the dissolution voids in carbonate rocks at the contact with terra rossa. however, very often they are not clearly recognisable in the bt horizon. verhaye & stoops (1973) consider that, as a result of repeated swelling and shrinking, clay coatings in terra rossa are broken and incorporated into the groundmass, first in the form of papules, and later as smaller, less differentiated units. fed/clay ratios are relatively uniform in terra rossa from istria and clearly indicate a predominance of co-illuviation of clay and fe oxides, i.e. a connection between fe-oxides and the clay fraction (durn et al., 2001a). according to fedoroff (1997) rubification occurs in the upper horizons, then rubified soil material is translocated with the clays at depth. so, the translocation of clay particles is responsible for the distribution of the red colour throughout the whole profile. however, since they have been exposed to various climatic fluctuations terra rossa soils can be affected by eluviation, yellowing and secondary hydromorphy. erosion and deposition processes which were superimposed on karst terrains and induced by climatic changes, tectonic movements and/or deforestation might be responsible for both the patchy distribution of terra rossa and thick colluvial or alluvial terra rossa accumulations in uvala and dolina type of karst depressions (pedo-sedimentary complexes, soilsediments). yaalon (1997) stressed that accumulated soil material served as a substrate for the development of new soils and fertile agriculture over several millennia in the mediterranean area. 7. references altay, i. (1997): red mediterranean soils in some karstic regions of taurus mountains, turkey.– catena, 247–260. arduino, e., berberis, e., canaro, f. & forno, m.g. (1984): estimating relative ages from iron-oxide/ total iron ratios of soils in the western po valley (italy).– geoderma, 33, 39–52. balagh, t.m. & runge, e.c.a. (1970): clay rich horizons over limestone, illuvial or residual.– soil sci. soc. am. proc., 34, 534–536. barnhisel, r.i. & bertsch, p.m. (1989): chlorites and hydroxy-interlayered vermiculite and smectite.– in: dixon, j.b. & weed, s.b. (eds.): minerals in soil environments. 2nd ed., soil sci. soc. am.book series, 1, 729–787. bech, j., rustullet, j., garigó, j., tobías, f.j. & martínez, r. (1997): the iron content of some red mediterranean soils from northeast spain and its pedogenic significance.– catena, 28, 211–229. boero, v. & schwertmann, u. (1987): occurrence and transformations of iron and manganese in a colluvial terra rossa toposequence of northern italy.– catena, 14, 519–531. fig. 23 fe-oxide stained complex voluminous microlaminated clay coatings with sharp extinction zones. medulin profile. 35–43 cm, bt horizon. +n. length of photo – 1 mm. 98 geologia croatica 56/1 99durn: terra rossa in the mediterranean region: parent materials, composition and origin boero, v. & schwertmann, u. (1989): iron oxide mineralogy of terra rossa and its genetic implications.– geoderma, 44, 319–327. boero, v., premoli, a., melis, p., barberis, e. & arduino, e. (1992): influence of climate on the iron oxide mineralogy of terra rossa.– clays clay miner., 40, 8–13. bogunović, m., vidaček, ž., ratz, z., husnjak, s. & sraka, m. (2000): soil suitability map for cultivation purposes of republic of croatia, scale 1:300000.– soil science department, faculty of agronomy, university of zagreb. bresson, l.m. (1993): fersialsols.– 8eme version. inra, thiverval-grignon. bronger, a. & bruhn-lobin, n. (1997): paleopedology of terrae rossae – rhodoxeralfs from quaternary calcarenites in nw morocco.– catena, 28, 279–295. bronger, a. & sedov, s.n. (2002): vetusols and palaeosols: natural versus man-induced environmental change in the atlantic coastal region of morocco.– 17th world conference on soil science, paper no.1530, 1–12. bronger, a. & smolíková, l. (1981): herkunft der terrae calcis in der slowakei.– vestnik ustr. ust. geolog., 56, 145–156. bronger, a., ensling, j., gütlich, p. & spiering, h. (1983): rubification of terrae rossae in slovakia: a mösbauer effect study.– clays clay miner., 31, 269–276. chiesa, s., coltorti, m., cremaschi, m., ferraris, n., floris, b. & prosperi, l. (1990): the loess and quaternary deposits in the marche region.– in: cremaschi, m. (ed.): the loess in northern and central italy. centro di studio per la stratigrafia e petrografia delle alpi centrali, editrice gutenberg, milano, 103–132. condie, k.c. (1991): another look at rare earth elements in shales.– geochimica et cosmochimica acta, 55, 2527–2531. cremaschi, m. (1987): paleosols and vetusols in the central po plain, a study in quaternary geology and soil development.– edizioni unicopli, milano, 306 p. cremaschi, m. (1990a): stratigraphy and palaeoenvironmental significance of the loess deposits on susak island (dalmatian archipelago).– quaternary international, 5, 97–106. cremaschi, m. (1990b): the loess in northern and central italy: a loess basin between the alps and the mediterranean regions.– in: cremaschi, m. (ed.): the loess in northern and central italy. centro di studio per la stratigrafia e petrografia delle alpi centrali, editrice gutenberg, milano, 15–19. cullers, r.l., basu, a. & suttner, l.j. (1988): geochemical signature of provenance in sand-size material in soils and stream sediments near tobacco root batholith, montana, usa.– chemical geology, 70, 335–348. ćirić, m. & aleksandrović, d. (1959): a view on the genesis of terra rossa.– zbornik radova poljoprivrednog fakulteta, 7, 1–12, beograd. danin, a., gerson, r. & carty, j. (1983): weathering patterns on hard limestone and dolomite by endolithic lichens and cyanobacteria: supporting evidence for eolian contribution to terra rossa soil.– soil science, 136, 213–217. douglas, l.a. (1989): vermiculites.– in: dixon, j.b. & weed, s.b. (eds.): minerals in soil environments. 2nd ed., soil sci. soc. am.book series, 1, 635–674. duchaufour, p. (1982): pedology: pedogenesis and classification.– allen and unwin, london, 448 p. durn, g. (1996): podrijetlo, sastav i uvjeti nastanka terra rosse istre (origin, composition and genesis of terra rossa in istria).– unpubl. phd thesis (in croatian), university of zagreb, 204 p. durn, g. & aljinović, d. (1995): heavy mineral assemblage in terra rossa from the peninsula of istria, croatia.– 1st croatian geological congress, abstracts, opatija, 31. durn, g., marchig, v. & ottner, f. (2001b): distribution of rare earth elements in different grain-size fractions of terra rossa soils in istria, croatia.– conference of the mid-european clay groups, book of abstracts, stara lesna, slovakia, 38. durn, g., ottner, f. & slovenec, d. (1999): mineralogical and geochemical indicators of the polygenetic nature of terra rossa in istria, croatia.– geoderma, 91, 125–150. durn, g., ottner, f., tišljar, j., mindszenty, a. & barudžija, u. (2003): regional subaerial unconformities in shallow-marine carbonate sequences of istria: sedimentology, mineralogy, geochemistry and micromorphology of associated bauxites, palaeosols and pedo-sedimentary complexes.– in: vlahović, i. & tišljar, j. (eds.): evolution of depositional environments from the palaeozoic to the quaternary in the karst dinarides and the pannonian basin. field trip guidebook, 22nd ias meeting of sedimentology, opatija 2003. durn, g., slovenec, d. & čović, m. (2001a): distribution of iron and manganese in terra rossa from istria and its genetic implications.– geologia croatica, 54/1, 27–36. durn, g., slovenec, d. & šinkovec, b. (1992): eolian influence on terra rossa in istria.– 7th international congress of icsoba, abstracts, balatonalmadi, 89. fao (1974): soil map of the world, 1:5 mill., volume 1. legend.– unesco, paris. fedoroff, n. (1997): clay illuviation in red mediterranean soils.– catena, 26, 171–189. frezzoti, m. & narcisi, b. (1996): late quaternary tephra-derived palaeosols in central italy’s carbonate apennine range: stratigraphical and palaeoclimatological implications.– quaternary international, 34–36, 147–153. garcia-gonzales, m.t. & recio, p. (1988): geochemistry and mineralogy of the clay fraction from some spanish terra rossa.– agrochimica, 32, 161–170. gvirtzman, g. & wieder, m. (2001): climate of the last 53,000 years in the eastern mediterranean, based on soil-sequence stratigraphy in the coastal plain of israel.– quaternary science reviews, 20/18, 1827–1849. jackson, m.l., clayton, r.n., violante, a. & violante p. (1982): eolian influence on terra rossa soils of italy traced by oxygen isotopic ratio.– in: van olphen, h. & veniale, f. (eds.): 7th int. clay conf. pavia, italy, 293–301. 100 geologia croatica 56/1 jahn, r., zarei, m. & stahr, k. (1991): genetic implications of quartz in “terra rossa”-soils in portugal.– proceedings of 7th euroclay conference, dresden, 541546. kišpatić, m. (1912): bauxites des kroatischen karstes und ihre einstehung.– n. jb. min. geol. pal., 34, 513–552. kubiëna, w.l. (1953): the soils of europe.– thomas murby and co., london, 317 p. land, m., ohlander, b., ingri, j. & thunberg, j. (1999): solid speciation and fractionation of rare earth elements in a spodosol profile from northern sweden as revealed by sequential extraction.– chemical geology, 160, 121–138. lehouerou, h.n. (1992): vegetation and land use in the mediterranean basin in the year 2050: a prospective study.– in: jeftić, l., millimann, j.d. & sestini, g. (eds.): climatic change and the mediterranean. vol. 1., 175–232. lippi-boncampi, c., mackenzie, r.c. & mitcheel, w.a. (1955): the mineralogy of some soils from central italy.– clay mineral bulletin, 2, 281–288. macleod, d.a. (1980): the origin of the red mediterranean soils in epirus, greece.– j. soil sci., 31, 125–136. malez, m. (1981): krško podzemlje istre kao prostor za naseljavanje fosilnih ljudi.– in: ekl, v. (ed.): liburnijske teme, 4, 119–135, opatija. marić, l. (1964): terra rossa u karstu jugoslavije.– acta geologica, 4, 19–72, zagreb. marinčić, s. & matičec, d. (1991): tektonika i kinematika deformacija na primjeru istre (tectonics and kinematic of deformations – an istrian model).– geol. vjesnik, 44, 247–268, zagreb. moresi, m. & mongelli, g. (1988): the relation between the terra rossa and the carbonate-free residue of the underlying limestones and dolostones in apulia, italy.– clay minerals, 23, 439–446. muhs, d.r., bush, c.a. stewart, k.c. (1990): geochemical evidence of saharan dust parent material for soils developed on quaternary limestone of caribbean and western atlantic islands.– quaternary research, 33, 157–177. muhs, d.r., crittenden, r.c., rosholt, j.n., bush, c.a. & stewart, k.c. (1987): genesis of marine terrace soils, barbados, west indies: evidence from mineralogy and geochemistry.– earth surface processes and landforms, 12, 605–618. nihlen, t & olsson, s. (1995): influence of eolian dust on soil formation in the aegean area.– zeitschrift für geomorphologie, 39/3, 341–361. olson, c.g., ruhe, r.v. & mausbach, m.j. (1980): the terra rossa limestone contact phenomena in karst.– southern indiana soil sci. soc. am. j., 44, 1075–1079. plaster, r.w. & sherwood, w.c. (1971): bedrock weathering and residual soil formation in central virginia.– geol. soc. am. bull., 82, 2813–2826. polšak, a. & šikić, d. (1973): osnovna geološka karta sfrj 1:100.000, tumač za list rovinj (basic geological map of sfry, 1:100000, geology of the rovinj sheet).– institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd, 51 p. rapp, a. (1984): are terra rossa soils in europe eolian deposits from africa?– geologiska foreninges et stockholm forhandlingar, 105, 161–168. singer, a., schwertmann, u. & friedl, j. (1998): iron oxide mineralogy of terre rosse and rendzinas in relation to their moisture and temperature regimes.– european journal of soil science, 49, 385–395. soil survey staff (1975): soil taxonomy: a basic system of soil classification for making and interpreting soil surveys.– usda handbook no. 436, u.s. government printing office, washington, d.c. šinkovec, b. (1974): porijeklo terra rosse istre.– geološki vjesnik, 27, 227–237. škorić, a. (1979): dvoslojni profili tla na području terra rosse u istri.– zemljište i biljka, 28, 111–131, beograd. škorić, a. (1986): dvoslojni profili tla na području terra rosse u istri.– special publication of agricultural scientific meeting, fakultet poljoprivrednih znanosti sveučilišta u zagrebu, zagreb, 172 p. škorić, a. (1987): pedosfera istre.– project council of pedological map of croatia, special ed., 2, zagreb, 192 p. šušnjara, a. šćavničar, b. & gabrić, a. (1994): the occurrence of vitric tuff in the quaternary deposits of gljev in dalmatia (southern croatia).– geologia croatica, 47/2, 193–198. tišljar, j., vlahović, i., velić, i., matičec, d. & robson, j. (1998): carbonate facies evolution from the late albian to middle cenomanian in southern istria (croatia): influence of synsedimentary tectonics and extensive organic carbonate production.– facies, 38, 137–152. torrent, j. (1995): genesis and properties of the soils of the mediterranean regions.– dipartimento di scienze chimico-agrarie, universitá degli studi di napoli federico ii, 111 p. torrent, j. & cabedo, a. (1986): sources of iron oxides in two reddish brown soil profiles from calcarenites in southern spain.– geoderma, 37, 57–66. tućan, f. (1912): terra rossa, deren natur and entstehung.– jahrbuch min. geol. pal., xxxiv beilage, 401–430. velić, i., tišljar, j., matičec, d. & vlahović, i. (1995): a review of the geology of istria.– in: vlahović, i. & velić, i. (eds.): 1st croatian geological congress, excursion guide-book, opatija, 21–30. verheye, w. & stoops, g. (1973): micromorphological evidences for the identification of an argillic horizon in terra rossa.– proceedings of the fourth international working meeting on soil micromorphology, 817–831. yaalon, d.h. (1997): soils in the mediterranean region: what makes them different?– catena, 28, 157–169. yaalon, d.h. & ganor, e. (1973): the influence of dust soils during the quaternary.– soil sciience, 116, 233–251. manuscript received april 2, 2003. revised manuscript accepted june 20, 2003. 03-belkhatir.indd 31 � ab stra ct this laboratory investigation has been conducted to elucidate how the fi nes fraction affects the undrained residual shear strength and liquefaction potential of sand-silt mixtures (algeria). a series of monotonic and cyclic undrained triaxial tests were carried out on undrained, reconstituted, saturated samples of sand with varying fi nes content ranging from 0 to 50%. these were undertaken in order to evaluate the effect of the fi nes fraction on the undrained residual shear strength and liquefaction potential of loose, medium dense, and dense sand-silt mixtures (dr = 17%, 53%, 62% and 91%), under an initial confi ning pressure of 100 kpa. the results of the monotonic tests indicate that the stress-strain response and shear strength behaviour is controlled by the percentage of the fi nes fraction and the samples become contractive for the studied relative density (dr = 17% and 91%). the undrained residual shear strength decreases as the gross void ratio decreases, and the fi nes content increases up to 30%. above this level of fi nes, it decreases with increasing gross void ratio. moreover, the undrained residual strength decreases linearly as the fi nes content and the intergranular void ratio increase. cyclic test results show that for the studied amplitude, the increase in fi nes content leads to an acceleration of liquefaction. the liquefaction resistance decreases with the increase in gross void ratio and the loading amplitude. keywords: silty sand, residual shear strength, fi nes content, cyclic tests, liquefaction, pore pressure the undrained shear strength characteristics of silty sand: an experimental study of the eff ect of fi nes � mostefa belkhatir1, hanifi missoum2, ahmed arab1, noureddine della1 and tom schanz3 1laboratory of materials sciences & environment, university of chlef, algeria 2laboratory of construction, transport and environment protection, university of mostaganem, algeria 3laboratory of foundation engineering, soil and rock mechanics, bochum ruhr university, germany corresponding author (abelkhatir@yahoo.com) doi: 104154/gc.2011.03 geologia croatica 64/1 31–39 14 figs. 2 tabs. zagreb 2011 geologia croaticageologia croatica 1. introduction on october 10th, 1980 at 13:25:23.7 local time (12:25:23.7 gmt) a destructive earthquake took place near chlef city, algeria (formerly known as el-asnam). chlef is approximately 200 km west of algiers. the richter magnitude, m, of this event was 7.2, which corresponds to a surface wave magnitude, ms, of 7.3. the epicenter of the quake was located at 36.143° n and 1.413° e, 10 km east of chlef. the focal depth of the earthquake was about 10 km , and its approximate duration was between 35 and 40 sec. the earthquake devastated the city of chlef, with the population estimated at 125,000, and nearby towns and villages. the large loss of life (reportedly 5,000 to 20,000 casualties) and property was attributed to the collapse of buildings. in several places in the affected area, especially along the chlef river banks, huge masses of sandy soils were ejected on to the surface. important damage to different structures was recorded. during earthquakes, the ground shakes, causing the loss of strength in cohesion less soils. as the soil behaves in a geologia croatica 64/1geologia croatica 32 manner similar to liquids, this phenomenon is called soil liqu efaction. liquefaction can cause settlements, landslides, earth dam failures, or other hazards. knowledge and understanding of liquefaction phenomena has signifi cantly improved in recent years. most liquefaction research was carried out on clean sands with the assumption that the behaviour of silty sand is similar to that of clean sands. recent research by zlatovic & ishihara (1995), lade & yamamuro (1997), thevanayagam et al. (1997), thevanayagam (1998), yamamuro & lade (1998), amini & qi (2000), naeini (2001), naeini & baziar (2004), indicate that sand deposited with silt can suffer greater liquefaction than clean sand. also, strain properties and pore pressure generation in silty sand samples are quite different from clean sand. these new discoveries emphasize the specifi c important features of deposits with a mixture of sand and silt. moreover, the behaviour of silty-sandy soils such as hydraulic fi lls during earthquakes is not clearly understood. therefore, further study of the behaviour of silty sand is needed for liquefaction assessment of silty sandy soils. post-earthquake behaviour of silty sand and, consequently, the stability of structures founded on liquefi ed soil depend on the post-liquefaction shear strength of soil. the strength of soils mobilized at the quasi-steady state has important implications for engineering practice (ishihara, 1993). laboratory study, especially in the last ten years, has made a great contribution in clarifying parameters that control the residual shear strength, and provide some principles for selecting the appropriate undrained residual shear strength for design and analysis. 2. laboratory testing program 2.1. soils tested sand samples were collected from the liquefi ed layer of the deposits close to the epicentre of the chlef earthquake (october 10th, 1980). chlef sand has been used for all tests presented here. individual sand particles are subrounded and the predominant minerals are feldspar and quartz. the tests were conducted on mixtures of chlef sand and silt. liquid limit and plastic limit of the silt are 27% and 22% respectively. chlef sand was mixed with 0 to 50% silt to obtain varying silt contents. the dry pluviation method was employed in the present study to prepare the soil samples for the monotonic and cyclic testing. the index properties of the sand-silt mixtures used during this investigation are summarized in table 1. grain size distribution curves of the soils are shown in figure 1. variation of emax (maximum void ratio corresponding to the loosest state of the soil sample) and emin (minimum void ratio corresponding to the densest state of the soil sample), versus the fi nes content fc (the ratio of the weight of silt to the total weight of the sand-silt mixture) is given in figure 2. we note that the two indices decrease with an increase of the fi nes content until fc = 30%, then, they decrease with further increase in the amount of fi nes. 2.2. experimental program and test procedure the present experimental study has been conducted to elucidate how the fi nes fraction affects the liquefaction potential and steady-state strength of mixed samples of sand. for this purpose, a series of undrained triaxial compression tests under monotonic loading conditions was carried out on reconstituted saturated samples of chlef sand with silt content ranging from 0 to 50%. all specimens were prepared by fi rst estimating the dry weights of sand and silt needed for the desired proportion into the loose, medium dense and dense state (dr = 17, 53, 62% and 91%), using the undercompacfi gu re 1: grain size distribution curves of tested materials. table 1: index properties of chlef sand-silt mixtures. material fc (%) gs d10 (mm) d50 (mm) cu cc emin emax ip (%) sand 0 2.680 0.22 0.68 3.36 1.36 0.535 0.854 silty sand 10 2.682 0.08 0.50 7.75 2.76 0.472 0.798 20 2.684 0.038 0.43 15.26 1.31 0.431 0.748 30 2.686 0.022 0.37 23.18 0.57 0.412 0.718 40 2.688 0.015 0.29 27.33 0.64 0.478 0.732 50 2.69 0.011 0.08 28.18 0.67 0.600 0.874 silt 100 2.70 0.72 1.420 5.0 belkhatir et al.: the undrained shear strength characteristics of silty sand: an experimental study of the eff ect of fi nes geologia croatica 33 tion method of sample preparation. this simulates a relatively homogeneous soil condition and is performed by compacting dry soil in layers to a selected percentage of the required dry unit weight of the specimen (ladd, 1978). the samples were 70 mm in diameter and 70 mm in height in order to avoid the appearance of shear banding (sliding surfaces) and buckling. after the specimen has been formed, the specimen cap is placed and sealed with o-rings, and a partial vacuum of 25 kpa is applied to the specimen to reduce the disturbances. saturation was performed by purging the dry specimen with carbon dioxide for approximately 30 min. water was then introduced into the specimen from the bottom drain line. water was allowed to fl ow through the specimen until an amount equal to the void volume of the specimen was collected in a beaker through the specimen’s upper drain line. a minimum skempton coeffi cient-value, greater than 0.96, was obtained at a back pressure of 100 kpa. all test specimens were isotropically consolidated at a mean effective pressure of 100 kpa, and then subjected to undrained monotonic triaxial loading with a constant strain rate of 0.167% per minute (cell pressure = 600 kpa and back pressure = 500 kpa). all undrained triaxial tests for this study were carried out at a strain rate, which was slow enough to allow pore pressure change to equalize throughout the sample with the pore pressure measured at the base of sample. all the tests were continued up to 24% axial strain. according to some authors kenny (1977); mitchell (1993), the behaviour of a sand-silt mixture depends on the intergranular void ratio (es): e vse v f svv = ( )v vv fv vv (1) where vv, vf, and vs are the volume of voids, fi nes and sand grains, respectively. thus vv + vf is the volume of intergranular void space. when the specifi c gravity of the silt and sand are very close to each other, the intergranular void ratio (es) can be determined with the gross void ratio (e) and the fi nes content (fc) using the following expression thevanayagam (1998): e e se c c = − ( /fcff ) ( /fcff ) 100 1 100 (2) figure 3 shows the variation of the gross and intergranular void ratios versus fi nes content at 100 kpa mean confi ning pressure for the initial relative densities (dr = 17%, 91%). as could be seen in this figure, the gross void ratio (e) decreases with the fi nes content until the value of 30% and then increases, however, the intergranular void ratio (es) increases hyperbolically with the increase in fi nes content. this showed that the gross void ratio cannot represent the amount of particle contacts in silty sands. as the void ratio and proportion of the coarse and fi ne-grained soil changes, the nature of their microstructures also changes. fi gu re 2: extreme void ratios of the sand-silt mixtures versus fi nes content. table 2: summary of monotonic compression triaxial test results. test no material fc(%) dr(%) γd (g/cm3) e ef es sus(kpa) 1 2 sand 0 17 91 1.49 1.72 0.815 0.567 0.800 0.564 0.800 0.564 16.85 20.14 3 4 silty sand 10 17 91 1.54 1.79 0.760 0.505 0.743 0.501 0.937 0.668 15.05 18.84 5 6 20 17 91 1.59 1.84 0.710 0.463 0.694 0.459 1.118 0.824 13.93 17.64 7 8 30 17 91 1.61 1.87 0.680 0.443 0.666 0.439 1.380 1.056 12.81 16.52 9 10 40 17 91 1.59 1.79 0.700 0.503 0.689 0.501 1.815 1.502 10.95 14.83 11 12 50 17 91 1.47 1.66 0.840 0.630 0.827 0.625 2.654 2.250 07.45 13.38 e − initial gross void ratio ef − post-consolidation gross void ratio es − post-consolidation intergranular void ratio dr − post-consolidation relative density geologia croatica 64/1geologia croatica 34 3. monotonic test results 3.1. undrained compression loading tests figures 4 and 5 show the results of the undrained monotonic compression triaxial tests carried out for different fi nes contents ranging from 0 to 50% at 100 kpa mean confi ning pressure within two separate density ranges (dr = 17%, 91%). generally, the increase in the amount of fi nes leads to a decrease in the deviatoric stress. this increase results from the role of the fi nes in increasing the contractancy phase of the sand-silt mixtures, leading to a reduction of the confi ning effective pressure and consequently to a decrease of the peak resistance of the mixtures as illustrated by figures 4a and 5a. the stress path in the (p’, q) plane clearly shows the role of the fi nes in the decrease of the average effective pressure and the maximum deviatoric stress (figs. 4b and 5b). in this case, the effect of fi nes on the undrained behaviour of the mixtures is observed for the lower fi nes contents (0% and 10%), and becomes very marked beyond 20%. these results are in good agreement with the observations of shen et al. (1977) and troncoso & verdugo (1985). table 2 presents a summary of the undrained monotonic compression triaxial test. 3.2. undrained residual shear strength when loose and medium dense sandy soils are subjected to undrained loading beyond the point of peak strength, the undrained shear strength declines to a near constant value over large deformation. conventionally, this shear strength is called the undrained steady-state shear strength or residual shear strength. however, if the shear strength increases after passing through a minimum value, the phenomenon is called limited or quasi-liquefaction. even limited liquefaction may result in a signifi cant strain and associated drop in resistance. ishihara (1993) defi ned the residual shear strength sus as: sus = (qs/2)cosφs = (m/2) cosφs(ps’) (3) m= (6 sinφs)/(3sinφs) (4) where qs, ps’ and φs indicate the deviator stress (σ1’σ3’), the effective mean principal stress (φ1’+ 2φ3’)/3 and the mobilized angle of inter-particle friction at the quasi-steady state (qss) respectively. for the undrained tests conducted at a constant confi ning pressure and various initial relative densities and fi nes content, the deviatoric stress (qs) was estimated at quasi-steady state point along with the mobilized internal friction angle. furthermore, the residual shear strength was calculated according to relationship (3). figure 6 shows the undrained residual shear strength versus the gross void ratio and fi nes content. it is clear that the undrained shear strength decreases linearly as the gross void ratio decreases and fi nes content increases for the loose and dense state of the specimen (dr = 17% and 91%) up to 30% fi nes content. therefore, when decreasing the gross void ratio and increasing the fi nes content, the undrained residual shear strength also decreases. in this case the gross void rafi gu re 4: undrained monotonic response of the sand-silt mixtures (σ3’=100 kpa, dr = 17%). fi gu re 3: variation of void ratios with fi nes content and relative density (σ3’= 100 kpa). belkhatir et al.: the undrained shear strength characteristics of silty sand: an experimental study of the eff ect of fi nes geologia croatica 35 tio does not represent the real behaviour of silty sandy soil in the range of 0–30% fi nes content. indeed, the gross void ratio appears to be a parameter not as pertinent in sand-fi nes mixtures as in clean sands for characterizing the mechanical state of these materials. beyond fc = 30% the undrained shear strength continues to decrease almost linearly with increasing gross void ratio and the fi nes content for the two relative densities (dr = 17% and 91%) figure 7 illustrates the undrained residual shear strength versus the fi nes content. it can be concluded that the undrained residual shear strength of the sand-silt mixtures sus varies linearly for the two relative densities (dr = 17% and 91%) allowing it to be estimated in the fi eld with no need for in-situ physical parameter measurements in the case of normally consolidated soils (σv’= σc’). in this laboratory investigation, for the range of 0% to 50% fi nes content in normally consolidated undrained triaxial compression tests, the following expressions are suggested in order to evaluate the undrained residual shear strength which is a function of the fi nes content (fc): sus= 17 – 0.17(fc) for dr = 17% sus= 20 – 0.14(fc) for dr = 91% figure 8 shows the undrained residual shear strength versus the intergranular void ratio. it seems that the variation of the undrained residual strength due to the amount of fi nes is related to the intergranular void ratio in the range 0–50% fi nes content. in this case, the behaviour of silty sand samples is infl uenced by the contacts of coarser grains, which is quantifi ed by the intergranular void ratio. by increasing the fi nes content in the range of 0–50%, the contact between sand grains decreases and therefore the intergranular void ratio increases and the undrained residual shear strength decreases. hence, in the range of 0–50% fi nes content, we could assume that the undrained residual shear strength defi gu re 6: variation of the undrained residual strength with gross void ratio and fi nes content (σ3’=100 kpa). fi gu re 7: undrained residual shear strength versus fines content (σ3’=100 kpa). fi gu re 5: undrained monotonic response of the sand-silt mixtures (σ3’=100 kpa, dr = 91%). geologia croatica 64/1geologia croatica 36 creases linearly with the increasing intergranular void ratio. in this case, the following expressions are suggested to evaluate the undrained residual shear strength which is a function of the intergranular void ratio (es), for the range of 0% to 50% fi nes content in normally consolidated undrained triaxial compression tests: sus= 20 – 4.73(es) for dr = 17% sus= 21 – 3.77(es) for dr = 91% figure 9 shows the variation of residual shear strength (sus) with relative density (dr) at various fi nes contents. it is clear from this figure that an increase in the relative density results in an increase in the undrained residual shear strength at a given fi nes content. thevanayagam et al. (1997) and sitharam et al. (2004) report similar behaviour of increasing residual shear strength with increasing relative density. the present laboratory study focuses on the effect of the fi nes content and the intergranular void ratio on the undrained residual shear strength of silty sands at various relative densities (dr = 17% and 91%). it can be noticed from the results of this study that there is a signifi cant decrease in the undrained residual shear strength with increase in the fi nes content or the intergranular void ratio, but there is a signifi cant increase in the undrained residual shear strength with increase in relative density. this aspect of the present study is in good agreement with experimental work reported by ishihara (1993) on the tia juana silty sand, baziar & dobry (1995) on silty sands retrieved from the lower san fernando dam, and by naeini & baziar (2004) on the adebil sand with different fi nes contents. 4. cyclic tests results 4.1. undrained loading tests three series of stress-controlled cyclic triaxial tests were carried out on isotropically consolidated soil specimens with different fi nes contents ranging from 0–40% and alternated symmetric deviator stress under undrained conditions, simulating essentially undrained fi eld conditions during earthquakes, in order to produce liquefaction potential curves of the sand-silt mixtures. throughout the test program, a frequency of 0.5 hz was used. the fi rst test included three alternating cyclic tests on clean sand samples (fc= 0%) with a relative density of 53% and a confi ning initial pressure of 100 kpa. the loading amplitudes of the cycles (qm) were 30, 50 and 70 kpa. the tests of the second series were undertaken on the sand-silt samples with a fi nes content of 10% and loading amplitudes of 30, 40 and 60 kpa; while the third series of tests concerned samples with a fi nes content of 40% and loading amplitudes of 20, 30 and 50 kpa. it is noted that the presence of fi nes considerably affects the liquefaction of the samples. figure 10 illustrates the results of the test carried out on clean sand samples (fc = 0%) with loading amplitude of 30 kpa. it is clear from the figure that the pore water pressure increases during the cycles resulting in a reduction of the average effective pressure. the rate of increase in the pore pressure remains low, because liquefaction is obtained only after 158 cycles (figure 10). for the test with qm = 30 kpa and a fi nes content of 10%, an important increase in the pore water pressure during 27th cycle was observed, with a signifi cant development of the axial strain (2.5%) leading to the liquefaction of the sand-silt mixture sample (figure 11). the test with loading amplitude of 30 kpa and a fi nes content of 40%, showed an important increase in the pore water pressure during the 3rd cycle, with a signifi cant development of the axial strain leading to the liquefaction of the sample at the 4th cycle (figure 12). this shows that the increase in the amount of fi nes in the range of (0–40%) leads to an increase in the risk of liquefaction. 4.2. eff ect of fi nes on the liquefaction potential figures 13a and 13b show the variation of the cyclic stress ratio (csr= qmax/2σc’) and the cyclic liquefaction resistance fi gu re 8: undrained residual shear strength versus intergranular void ratio and fi nes content (σ3’=100 kpa). fi gu re 9: undrained residual shear strength versus relative density and fi nes content (σ3’=100 kpa). belkhatir et al.: the undrained shear strength characteristics of silty sand: an experimental study of the eff ect of fi nes geologia croatica 37 (clr) with the number of cycles (nc) and fi nes content. according to ishihara (1993), the cyclic liquefaction resistance (clr) is defi ned as the cyclic stress ratio leading to liquefaction for 15 cycles. it was observed that the liquefaction potential of the sand-silt mixture decreases with further increase in the fi nes content. these results confi rm those found during monotonic tests showing that the increase in the fi nes content leads to an increase in the contractancy pha se. consequently, the increase of the contractancy phase induced a reduction in the liquefaction potential with the increase in fi nes content. for the mixtures of chlef sand-silt, the presence of fi ne grained soils increases the phase of contra ctancy resulting in a signifi cant decline of the liquefaction potential. it should be noted that for the studied amplitude (qm = 30 kpa), the increase in fi nes content leads to an acce leration of the liquefaction. figure 13c shows the cycles of loading till the liquefaction versus the fi nes content. we notice that the liquefaction resistance decreases fi gu re 10: undrained cyclic response of clean sand (ef = 0.685, es = 0.685, qm = 30 kpa, dr = 53%, σ3’ = 100 kpa). fi gu re 11: undrained cyclic response of sand-silt mixture (ef = 0.625, es = 0.806, qm = 30 kpa, dr = 53%, σ3’ = 100 kpa). fi gu re 12: undrained cyclic response on sand-silt mixture (ef = 0.597, es = 1.662, qm = 30 kpa, dr = 53%, σ3’ = 100 kpa). geologia croatica 64/1geologia croatica 38 with the increase in the fi nes content. the samples sheared with higher le vel loading (csr = 0.25) are more vulnerable to liquefaction than those sheared with smaller loading level (csr = 0.15). 4.3. eff ect of the relative density undrained cyclic tests were performed on chlef sand–silt mixtures (fc = 5%) for two relative densities (dr = 17% and 62%). for each density, we have varied the loading amplitude in order to draw the liquefaction potential curve. the tests were carried out for amplitudes qm = 30, 50 and 70 kpa. liquefaction was reached quickly for the higher amplitudes: after 2 and 3 cycles respectively for loading amplitudes of qm = 70 and 50 kpa. liquefaction under loading amplitude qm = 30 kpa and relative density dr = 17% was reached at 24 cycles. for the tests carried out with a relative density of dr = 62% and for the same loading amplitudes, liquefaction occurred at 5, 13 and 167 cycles. figure 14 summarizes all the test results. figure 14a illustrates the infl uence of relative density on the liquefaction potential of chlef sand-silt mixture (fc = 5%). it shows clearly that the increase in the relative density leads to an increase in the liquefaction resistance of the chlef sand-silt mixture. figure 14b shows the infl uence of the gross void ratio on the liquefaction resistance of the sand-silt mixtures. this fi gure shows clearly that liquefaction resistance decreases with the increase in the gross void ratio and the loading amplitude. we note that the reduction in the liquefaction resistance of chlef sand-silt mixture becomes very marked for the smaller cyclic stress ratios csr = 0.15 and 0.25. 5. conclusion a series of undrained monotonic and cyclic triaxial tests were carried out on silty sand collected from liquefi ed sites on the chlef river, algeria. the effect of variation in the fi nes content was studied. in the light of the experimental evidence, the following conclusions can be drawn: undrained monotonic triaxial tests performed with two relative densities (dr = 17% and 91%) showed a contractive behaviour of the sand-silt mixtures samples at the initial confi ning pressure in the gross void ratio range tested. the undrained residual shear strength decreases as the gross void ratio decreases and the fi nes content increases up to 30%. fi gu re 13: eff ect of fi nes on the liquefaction potential of the sand-silt mixtures (σ3’ = 100 kpa, dr = 53%). fi gu re 14: eff ect of relative density on the liquefaction potential of chlef sand-silt mixture (σ3’=100 kpa, fc =5%). belkhatir et al.: the undrained shear strength characteristics of silty sand: an experimental study of the eff ect of fi nes geologia croatica 39 beyond this, it decreases with increasing gross void ratio and fi nes content. the undrained residual shear strength decreases linearly with increase in the fi nes content and the intergranular void ratio. the peak and residual strengths of the soil are sensitive to the presence of fi ne grained soils. as the fi nes content increases, the peak and the residual strengths decrease. the strength of silty sand up to 50% fi nes content is less than that of the clean sand. this means that the soil becomes weakened with an increase in the fi nes content up to 50%. undrained cyclic triaxial tests show that the liquefaction resistance of the sand-silt mixtures decreases with the increase of the fi nes content, and the samples sheared with higher level loading (csr= 0.25) are more vulnerable to liquefaction than those sheared with a smaller loading level (csr = 0.15). they also show that the liquefaction resistance increases with the relative density but it decreases with the increase in the gross void ratio and the loading amplitude. we note that the reduction in the liquefaction resistance of the sand-silt mixture becomes very marked for the smaller cyclic stress ratios csr = 0.15 and 0.25. these results confi rm those found during monotonic tests showing that the increase in the fi nes content leads to an increase of the contractancy phase inducing a reduction in the liquefaction potential when the fi nes content (fc) increases. for the sand-silt mixtures, the presence of fi nes increases the phase of contractancy resulting in a signifi cant decline of the liquefaction potential. it should be noted that for the studied amplitude (qm= 30 kpa), the increase in the fi nes content leads to an acceleration of liquefaction. references amini, f. & qi, g.z. (2000): liquefaction testing of stratifi ed silty sands.− journal of geotechnical geoenvironmental engineering, proc. asce, 126/3, 208−217. baziar, m.h. & dobry, r. (1995): residual strength and large-deformation potential of loose silty sands.− journal of geotechnical engineering, asce, 121, 896−906. ishihara, k. (1993): liquefaction and fl ow failure during earthquakes.− geotechnique, 43/3, 351−415. kenny, t.c. (1977): residual strengths of mineral mixtures.− proc. 9th int. conf. soil mech. and found. eng., tokyo, 1, 155−160. ladd, r.s. (1978): preparing test specimen using under compaction.− geotechnical testing journal, gtjodj, 1, 16−23. lade, p.v. & yamamuro, j.a. (1997): effects of non-plastic fi nes on static liquefaction of sands.− canadian geotechnical journal, 34, 918−928. mitchell, j.k. (1993): fundamental of soil behaviour.− john wiley interscience, new york, 2nd ed. naeini, s.a. (2001): the infl uence of silt presence and sample preparation on liquefaction potential of silty sands.− phd dissertation, tehran, iran. iran university of science and technology. naeini, s.a. & baziar, m.h. (2004): effect of fi nes content on steady-state strength of mixed and layered samples of a sand.− soil dynamics and earthquake engineering, 24, 181−187. shen, c.k., vrymoed, j.l. & uyeno, ck. (1977): the effects of fi nes on liquefaction of sands.− proc. 9th int. conf. soil mech. and found. eng., tokyo, 2, 381−385. sitharam, t.g., govinda raju, l. & srinivasa murthy, b.r. (2004): cyclic and monotonic undrained shear response of silty sand from bhuj region in india.− iset journal of earthquake technology. paper n° 450, 41/2–4, june 2−4, june-december 2004, 249−260. thevanayagam, s. (1998): effect of fi nes and confi ning stress on undrained shear strength of silty sands.− j. geotech. geoenviron. eng. div., asce, 124/6, 479−491. thevanayagam, s., ravishankar, k. & mohan, s. (1997): effects of fi nes on monotonic undrained shear strength of sandy soils.− astm geotechnical testing journal, 20/1, 394−406. troncoso, j.h. & verdugo, r. (1985): silt content and dynamic behaviour of tailing sands.− proc., 12th int. conf. on soil mech. and found. eng., san francisco, 1311−1314. yamamuro, j.a. & lade, p.v. (1998): steady-state concepts and static liquefaction of silty sands.− journal of geotechnical and geoenvironmental engineering, asce, 124/9, 868−877. zlatovic, s. & ishihara, k. (1995): on the infl uence of non-plastic fi nes on residual strength.− proceedings of the fi rst international conference on earthquake geotechnical engineering, tokyo, 14−16. manuscript received december 27, 2009 revised manuscript accepted december 15, 2010 available online february 22, 2011 geol. croat. 49/2 165 166 1 1 st international symposium of petroleum geology economic aspects of petroleum exploration an approach to rational exploration zagreb, april 18-19, 1996 conclusions 1 zagreb 1996 the following conclusions have been drawn based on oral presentation s and d iscussions given by eminent for­ e ign ancl domestic experts concerning ra lional expl oration for hydrocarbons. 1. the activ ity of hydrocarbon expl oration ancl production is always profitable in spite of occasionally occurring world energy crises, if a rational approach to exp loration and development of hydrocarbon pools is taken, regard less of natural conditions ancl condit ions of a pool. 2. the strategy of a sllccessful oi l company must include permanent investment in exploration so as to enable replenishment of the produced quantities with newly discovered reserves . 3. future exploration on the territory of the republic of croatia needs to be done in a rat ional manner according to the level of maturity of depositional basins. the areas characterised by high costs and high exploration risk should be targeted at jointl y with other companies. 4. in order to retain the dominant role in covering energy needs of croatia in the future, ina-naftaplin must sys­ tematically and continuall y evaluate both dom est ic exploration area and prospective areas in the world. the combination or high and low risk areas is imperative. each year the company is supposed to be present at least at ten projects in the world together with other companies and to have one project of its own. s. since the ratio of newly discovered reserves and production realised in croatia becomes less and less favoura­ ble, and the process of exp lorat ion, discovering and development takes a long time, the replenishment of reserves by purchas ing al ready discovered, developed or undeveloped reserves arises as a possible solu tion dependable on market conditions. 6. an adjustment of croatian legislation to the world praxis in the area of hydrocarbon explorat ion and related commercial agreements is necessary. 7 . there is an evident need for a systematic follow -up of scientific accomplishments in the world by entering the global circul ation of exchange and application of scientific information, which was confirmed on this sympo­ si um as well 166 i. medunarodni naftnogeologijski znanstveni skup ekonomski aspekti istraiivanja nafte i plina pristup racionalnom istraiivanju zagreb, 18-19. travanj 1996. zakljucci gcologi;] croatic;l 49(2 tcj11cijcm izlozenih radova i rasprava istaknutih siranih i domacih znanstvenika i slrucnjaka 0 promi sijenom istrazivanju ugljikovodika proizasii su s ljcdeci znkljucci. l. djcialnosl istrazivanja i proizvodnje ugljikovodika, usprkos povremenih pojava cncrgctski h kriza li sv ijel u, llvi ­ jck jc isplativ3 li z promisijeni prisiup istrazivanju i razrad i [czista bcz obzira na iciisne i clrugc prirodnc uvjcte. 2. stratcgija llspjcsnoga nartnog poduzeca 1110ra bili ncprckidno ulaganje ii islrazivanjc kako bi sc svake god ine proizyccicna kolicina mogja (u prosjeku) harem naclomjcstiti novootkrivenim zaliham <1. 3. dnljnja is traz ivanja u prostorima republikc hrvatske treba voditi razumno prema s lu pnju islrazenosti 1£1 lozni h prostora. u podrucjim3 koj£1 z£1hlijevaju v isoke iroskove is lr£1ziv£1 nja , islra7. ivacki ri z ik treba dije lit i 5 drugim kompanijama. 4. radi da lj njega zadrz.avanja lidje la u podmi ri vanj u e nergelskih polrcba hrvalske, ina-naftapli n ire ba, liz domaci i511"<l1.l1i pr0510r, s listavno i stalno vrednova ti i pe rspeklivna podrllcja 1i svijct ll. n uz l10 je poveza li, oclnosno ll skladili podrucja visokoga i niskoga rizi ka. godisnje bi irebalo bili prislililim u svije tu na najmanje dcsct pro­ jekala s drug im tvrtkama i samostalno barem l1a jccinom proje klu. 5. kako jc omjcr novootkrivenih zaliha i ostvarene proizvodnje u hrvatskoj svc ncpovo ljniji , a praees istrazivanja, olkri vanja i razrade dugotrajan , na svjetskom bi irzistu trebalo kupiti nove razradene iii ncrazradcnc za lihe raeli njihova obnavljanja. 6 . ilrvat sko zakonodavstvo potrebno je pri lagoditi svjetskoj praksi komercijalnih ugovora za poelrucjc islrazi vanja ugljikovodika. 7. poscbno sc isticc poi reba sustavnoga pracenja znanstve nih dos lignuca u svijetu ukljucivanjcm u svjctske tokovc razmjene i primjene znanstvcnih infonnacija, s[o .ie potvrdcno i na ovom znans tvcnom skupu. geo.cro.2-3-61-kb.pdf 385 � gabriella kiss1, ferenc molnár1 and ladislav a. palinkaš2 ab stra ct the darnó unit within the zagorje-mid-transdanubian megaunit is an allochtonous part of dinarides in ne-hungary and represents a relict of the neotethyan accretionary complex. it contains blocks of submarine basalts of triassic age in turbiditic sediments (olistrostrome) of jurassic age. the lava clogged in the lime mud at the original site of volcanism and developed closely packed pillow, pillow fragment hyaloclastite breccia, and peperite facies. interaction between the lava and the sea water produced mostly chloritic alteration of basalt and precipitation of hydrothermal calcite in amygdales, feeding channels of lava lobes and hyaloclastite breccia cements. calcite is associated with chlorite, epidote, hematite and pyrite. fluid inclusions in calcite infi llings record conditions of fl uid/rock interaction. salinities of fl uid inclusions (3.2–5.6 wt.% nacl equiv. wt.%.) are close to the salinity of recent sea water and their homogenization temperatures are in the range of 80–150°c. fluid inclusion data support interpretation that volcanic facies represent rapidly cooled distal zones away from the submarine volcanic centre. this is also confi rmed by the comparison to the volcanic and hydrothermal alteration facies of the submarine basalt lava-fl ow complex and associated pillow lava formation of triassic age in the hruškovec quarry in the kalnik mts., nw-croatia. the obtained data contribute to understanding of the early history of neotethyan evolution, i.e. dilemma about rifting or oceanization in triassic time and offer new aspects of correlation between units of dinaridic origin which had been displaced from their original setting by large scale tertiary tectonic processes. keywor ds: basalt pillow lavas, peperite, fl uid inclusions, triassic rifting, darnó unit, zagorje – mid-transdanubian megaunit, dinarides, ne-hungary, nw-croatia 1 department of mineralogy, eötvös loránd university, pázmány p. sétány 1/c, h-1117, budapest, hungary; (gabriella-kiss@chello.hu; molnar@abyss.elte.hu) 2 department of geology, faculty of science, university of zagreb, horvatovac bb, zagreb, croatia; (lpalinkas@geol.pmf.hr) volcanic facies and hydrothermal processes in triassic pillow basalts from the darnó unit, ne hungary geologia croatica 61/2–3 385–394 5 figs. zagreb 2008 geologia croaticageologia croatica � 1. introduction the darnó hill is located in northeast hungary, in the western forelands of the bükk mountains (fig. 1). the reszél hill and mély valley quarries are situated in this region, 10–15 km northwest from the town of eger. the quarries expose pillow lavas, peperites and hyaloclastite breccias as a part of basaltic extrusions into deep water sediments. a drilling project with three, 1200 m deep drill holes was completed in 1977–1979 in the darnó hill area. balla et al. (1980) found that the basaltic suite intercepted by those drillings is a result of an advanced rifting magmatism, rather than oceanization. downes et al. (1990) discussed the triassic age of the darnó hill igneous suite, and they distinguished it from the szarvaskő complex of jurassic age in the bükk mountains (fig. 1). dosztály & józsa (1992) argued that the age of the pillows is triassic but the most probable option is their mid-oceanic ridge origin. the geochemical character of these mafi c rocks is morb-like, and the rocks are olistolithes in an olistostrome formation (harangi et al., 1996). according to pamić (1997), the kalnik unit and the darnó-bükk units can be correlated as a part of the dinaridic ophiolitic complex within a jurassic olistostrome mélange. dimitrijević et al. (2003) interpreted the darnó unit as a geologia croatica geologia croatica 61/2–3 386 relict of the neotethyan accretionary complex, which was displaced from the nw dinarides to ne hungary along the zagreb-zemplén lineament; and shows similarity to the dinaridic ophiolite belt (fig. 1). recent studies by haas et al. (2006) confi rmed the earlier hypothetic palaeogeographical connection between these two regions during the jurassic time. in addition, the possible correlation might be extended to the hellenides (kovács et al., 2008). although, the correlation has been recognised, and confi rmed by tectonical and geological evidences during earlier studies, we present a new approach of matching triassic basalts of the kalnik mts. and darnó unit in this paper. the comparison is based on features pertained to the darnó hill area with those in the hruškovec quarry, kalnik mts. (halamić & goričan, 1995; palinkaš et al., 1998, 2000, 2008) and includes description of various facies of submarine basaltic volcanism and p-t-x characteristics of hydrothermal processes associated with the emplacement of basaltic rocks. this work offers a clue to the dilemma, whether the darnó hill basalts belong to the advanced rifting process or to the progressive oceanization of the tethys in triassic time. 2. methods of study the major aspects of fi eld studies were the reconstruction of the pillow lava complex, recognition of different submarine volcanic and hydrothermal facies as well as representative sampling of recognized environments. the fi eld observations were supplemented by the study of rocks and hydrothermal mineral parageneses in polished thin sections. x-ray powder diffraction (xpd) method was used to determine some mineral phases using a siemens d-5000 type, bragg-brentano geometric diffractometer emission (θ-θ working method, cu kα (λ=0.154178 nm), secondary graphite crystal monochromator and scintillation detector. fluid inclusion petrography and microthermometric study was carried out on 100 μm thick, double polished sections of hydrothermal calcite from various volcanic and hydrothermal facies of basalt using a chaixmeca type heating freezing stage mounted on an olympus bx-51 type polarizing microscope providing 1000 times magnifi cation. the precision of the microthermometric measurements was ±0.1°c below 0°c, and ±1°c above it. the calibration of the instrument was made by analysis of co2 and pure water synthetic fl uid inclusions. interpretation of microthermometric data were carried out by the bulk 01/03 and the isoc 01/03 software (bakker, 2003). 3. field observations the reszél hill quarry has three volcanic facies comparable with the known facies in the hruškovec quarry (kalnik mts., croatia; palinkaš et al., 1998, 2000, 2008). these are the closely packed pillows with some “pyjamas-style” lava lobes, the peperitic facies with red micritic limestones and the pillow fragment hyaloclastite breccias. these facies gradually developed sequentially from ne to sw along the profi le of the quarry, and all of the units are enclosed in the mónosbél complex represented by turbiditic shale (mónosbél formation) and bioclastic limestone (oldalvölgy formation) in the quarry (fig. 2). the age of the mónosbél complex is jurassic and consists of olistrostrome and re-sedimented carbonates. contacts of the basalt with the sedimentary units of jurassic age are evidently tectonic as there is no thermal effect on the sedimentary host rocks. hydrothermal features developed on the basalt (see below) are absent, but also in the sediments as well. also, occurrence of red micritic limestone, thermally affected by basalt lava is restricted to the peperitic facies and similar type of carbonates are absent in the surrounding sedimentary host rocks. thus the whole submarine volcanic unit is interpretfi gu re 1: sketch map of zagorjemid-transdanubian mega-unit, extruded along the two prominent regional fault lines, the periadriaticbalaton (pbl) and the zagreb-zemplén (zzl) lineaments. position of reszél hill and mély-valley basaltic suites is within the darnó unit located in the western forelands of the bükk mts. geologia croaticagabriella kiss et al.: volcanic facies and hydrothermal processes in triassic pillow basalts from the darnó unit, ne hungary 387 ed to be a large block (olistolite) which has been incorporated into the olistrostrome mélange of the mónosbél complex. the mély valley quarry also reveals distinctive submarine volcanic facies of basalt resembling to those in the reszél hill quarry. these are closely packed pillows, occasionally with calcite-fi lled feeding channels within the individual pillows and “pyjama-style” lava lobes and peperite with red micritic limestone. these facies are strongly dissected and tectonically fragmented and also intercalated partly with langobardian radiolarites and cherty limestone, proving the possible middle triassic age of the submarine volcanic activity (dosztály & józsa, 1992; dosztály et al., 1998) the basaltic units together with their sedimentary intercalations form 15–20 m long and several metres thick blocks in the olistostrome mélange (mónosbél complex) of jurassic age. hydrothermal features, characteristics of the basalt, are absent in the jurassic sedimentary units which also supports that basalts are exogeneous blocks (olistolithes) in the sedimentary host. 4. petrography of the submarine basaltic facies 4.1. closely packed pillow lava facies the closely packed pillow units contain lava lobes with diameters about 0.5 m (fig. 2b). the marginal pars of pillows are rich in amygdales with size up to 1 cm. these amygdales are fi lled with calcite and other hydrothermal minerals. the lava lobes are also dissected by tortoise shell joints and jigsaw veinlets with thickness from a few millimetres to about 2 centimetres (fig. 3a). the veins are within the pillows, and they do not cross the pillow’s boundaries, so it is obvious that they are primary ones, and they were formed during the cooling of the pillows. other characteristic textures related to the solidifi cation of the lava are the occurrences of “pyjama-style” pillows and feeding channels in the cores of pillows (figs. 3b and 4a). these features are also formed by rapid cooling of the basalt: in the place of “pyjama” ribbons and feeding channels, the lava was still molten when the crust has already been solidifi ed and outpouring of lava from these parts left behind open tubes in which calcite and other hydrothermal minerals were instantaneously precipitated from the heated sea water. in the case of the “pyjama-style” pillows, this process repeated in sequence several times and contemporaneous fl attening of the semi-consolidated lava lobe resulted in fl at voids with thickness about 2–3 cm and width up to several tens of centimetres. both the feeding channels and “pyjama” ribbons are geopetal structures with fl at bottom of the vug and irregularcurving upper boundary. “pyjama-style” lava lobes are characteristic features of the lava pillows developed during obfi gu re 2: occurrences of submarine volcanic facies in the quarry of reszél hill. a – panoramic view of the quarry. b – closely packed pillow facies. c – spherulitic surface and jigsaw fractures of a pillow in the transition zone between the closely packed pillow and peperitic pillow facies. d – peperitic pillow facies with red limestone mixed up with fragmented basalt. geologia croatica geologia croatica 61/2–3 388 fi gu re 3: macroscopic and microscopic features of diff erent volcanic facies, reszél hill, darnó unit. a – lava lobe in the closely packed pillow facies with tortoise shell joints and jigsaw veins fi lled up by calcite. b – pyjama-style pillow basalt. this characteristic feature of the submarine lava developed during obstructed propagation of lava into a soft sediment. flat vugs developed during this process have been fi lled up by hydrothermal calcite which was the object of fl uid inclusion studies. c – peperitic facies; blocks of reddish limestone within fragmented basalt pillows. d – pillow fragment hyaloclastite breccia. e – microphotography of closely packed pillow with acicular plagioclase (pl) in bundles and radial arrangements, submerged in a groundmass of glass, chlorite (chl) and accessories like hematite (hem), pyrite (py), (1n). f – microphotography of the basalt wall of the “pyjama-style” shelf and white infi llings of hydrothermal calcite. the basalt in the wall has variolitic texture made of radiating acicular plagioclase (pl) and oxidized to hematite (hem). amygdale and the inner compartment of the shelf are rimmed with hematite and sparry calcite (cc), (1n). g – microphotography of recrystallized reddish micritic limestone, the matrix of the peperitic breccia. sparry calcite (cc) in a cross-cutting vein and a biomold (bm). h – microphotography of hyaloclastite breccia. fragments of basalt (left corner) in the matrix of chlorite (chl) and basaltic glass (g). the matrix is cemented by sparry calcite (cc), (1n). geologia croaticagabriella kiss et al.: volcanic facies and hydrothermal processes in triassic pillow basalts from the darnó unit, ne hungary 389 fi gu re 4: macroscopic and microscopic features of diff erent volcanic facies, reszél hill and mély valley, darnó unit. a – pillow lobe with a circling belt of amygdales along the rim. in the centre of the lobe there is a feeding magma channel. amygdales and feeding channel are fi lled up by hydrothermal calcite, the object of fl uid inclusion studies. mély valley. b – hyaloclastite breccia consists of basalt fragments and sideromelane shards cemented by hydrothermal minerals (mostly calcite). mély valley. c – microphotography of spongy and water-clear calcite from the white part of the “pyjama-style” pillow shelf, the object of the fl uid inclusion study. reszél hill, (1n). d – primary fl uid inclusion with liquid (l) and vapour (v) phases in the water-clear calcite of the “pyjama-style” pillows. reszél hill, (1n). e – aphyric to microporphiritic texture of basalt with amygdales from the closely packed pillow facies. the plagioclase (pl) laths occur in bundles, often as skeletal crystals, sporadically accompanied by probably olivine (ol), and opaque minerals, such as pyrite (py) and hematite (hem). the amygdales are fi lled with sparry calcite (cc). mély valley, (1n). f – microphotography of the hyaloclastite breccia matrix. the matrix contains tiny fragments of oxidized basalt, hematite (hem), chlorite (chl), and epidote (ep) cemented by sparry calcite (cc). mély valley, (1n). g – microphotography of sparry calcite from the amygdales – the object of the fl uid inclusion study. calcite in the outer parts of amygdale has spongy appearance due to large amount of fl uid inclusions whereas it is water clear in the centre. mély-valley, (1n). h – primary fl uid inclusion in the sparry, water-clear calcite of the amygdales. mély valley, (1n). geologia croatica geologia croatica 61/2–3 390 structed propagation of lava into soft sediment (palinkaš et al., 2008), thus their occurrences in the vicinity (a few metres) of the peperitic basalt facies is expected. the basalt in the closely packed pillow facies is aphyric to microporphiritic, with abundant microcrysts. plagioclase laths (0.1–1.5 mm) occur in bundles, often as skeletal and radially arranged crystals, submerged in the glassy matrix (figs. 3e and 4e). plagioclase is sporadically accompanied by fewer amounts of altered olivine and clinopyroxene, as well as pyrite. in the coherent basaltic block of the reszél hill quarry, internal texture of individual pillows becomes variolitic whereas their rims are spherulitic towards the coherent peperitic facies (fig. 2c). among the pillows, minor amount of hyaloclastite breccia can be found in small pockets formed by joints of the pillows. the breccia is made of basalt fragments and sideromelane shards which are cemented by hydrothermal minerals. the shards are brown or brownish green, with rare crystallites. the opaque minerals are mostly hematite and thus basalt fragments are characterized with reddish colour due to oxidation attained during emplacement in the sea water. textures of basalt fragments are identical to the pillows. 4.2. peperitic pillow basalt facies the peperitic facies developed by intrusion of lava into the soft, water soaked lime mud. the result was quench fragmentation of the lava, and formation of blocky peperites, supported by matrix of reddish micritic limestone (figs. 2d and 3c). the peperitic facies form up to 3–5 m large irregular bodies in both quarries and it appears to have a transitional position between the closely packed pillows and pillow fragmented hyaloclastite breccia at the reszél hill quarry (fig. 2). the originally micritic limestone is mainly recrystallized therefore it has a sparry texture especially in biomolds (fig. 3g). biomolds gradually develop into sparry recrystallized limestone without bioclasts in irregular patches. texture of the basalt is variolitic-intersertal. the glassy groundmass contain prismatic, occasionally skeletal plagioclase (albite–oligoclase, 0.2–0.8 mm) occurring in small radial knots at some places. the groundmass also contains abundant disseminations of fi ne grained (0.01–0.02 mm) hematite pseudomorphs after pyrite in the red-coloured parts of basalt. a few altered mafi c minerals, most probably former clinopyroxene is also present in the rock. the recrystallized limestone and pillow basalts are both cut by tortoise or jigsaw-like cooling related fractures (2–6 mm thickness) fi lled up by calcite (fig. 2d). 4.3. pillow fragment hyaloclastite breccia facies the pillow fragment (hyaloclastite) breccia is matrix supported. basalt and sideromelane shards, as well as very rare limestone fragments occur as clasts, varying in size between 2 mm and 5 cm (figs. 3d and 4b). the colour of the glass shards is usually brown-green, containing sporadic crystallites of plagioclase. the breccia matrix contains calcite cement, represented by the two varieties, accompanied by rare anhedral chlorite, epidote and hematite (figs. 3h and 4f). the earlier generation calcite has a larger grain-size and cloudy appearance, while the younger one, determined with certainty as vein -fi lling, is entirely water-clear. fragmented pillow basalt in the hyaloclastite breccia displays similar textural and mineralogical variations as observed in the closely packed pillow and peperitic facies. 5. fluid-rock interaction and hydrothermal mineralization 5.1. features of fl uid rock interaction and hydrothermal minerals as one of the main results of the fl uid-rock interaction, the very rapid cooling of basalt resulted in the specifi c textures observed. that is why a high amount of glassy material, sometimes spherulitic, often variolitic, variolitic-intersertal and microporphyritic texture has been developed. skeletal growths of plagioclase, occurrences of radial knots of plagioclase in glassy groundmass, as well as alteration of mafi c rock forming minerals into chlorite and less frequently epidote and hematite is also the result of the vigorous interaction between the hot basalt and sea water. the plagioclase of basalt in various facies has albite–oligoclase composition and it is in contrast with common basalts, with ca-rich plagioclase. the hydrothermal alteration which happened because of the fl uid-rock interaction changed the plagioclase composition. during the process ca has been released and then blocked in calcite and rarely epidote in the veins, amygdales, and in the hydrothermal cementation of the hyaloclastite breccia. additional source of ca for the voluminous formation of carbonate and ca-rich silicates is the seawater itself. chlorite also occurs as a result of the wide-spread submarine hydrothermal alteration. during this process original silicates of the basalt (e.g. clinopiroxene, rarely olivine), even some parts of the glassy groundmass turned into chlorite, while sio2 has been released. that is why even quartz can be found in the veins or in the cement of the hyaloclastite breccia at some places. a specifi c form of precipitation of hydrothermal calcite is in the bands of the “pyjama-style” pillows. calcite has two generations in the infi llings: one is a water-clear and sparry and the other is spongy calcite containing abundant fl uid inclusions (fig. 4c). the spongy calcite occurs mostly at the margins of the white bands, so this should be the older generation. beside calcite, also chlorite, hematite and epidote are scarcely present in the bands with hydrothermal minerals (fig. 3f). the sparry calcite shows deformational structures (bending of cleavage planes), developed by numerous tectonic phases which affected the mélange formation. feeding channels in the center of pillows and amygdales along the rim of pillows have similar infi llings to the bands in the “pyjama-style pillows”. along the walls of the feeding channel and amygdales, calcite is spongy but it is water-clear in the middle of the infi llings. epidote and chlorite are present as well (fig. 4g). geologia croaticagabriella kiss et al.: volcanic facies and hydrothermal processes in triassic pillow basalts from the darnó unit, ne hungary 391 formation of jigsaw veins within pillow lava lobes is the result of cracking of the already solidifi ed rock during fast cooling. upheated sea water leaching out metals from the altered basalt plus components from the sea water precipitated mostly anhedral calcite grains (up to 1–2 mm size) with minor amount of quartz in these veins. chlorite is also a common mineral in these veins with some rare epidote. the matrix of hyaloclastite breccia also mostly contains fi ne grained (0.5–1.5mm) calcite associated with lesser amount of rounded aggregates of epidote, quartz–chalcedony and fl akes of chlorite and fi ne grained hematite. calcite also has two generations in the breccia matrix: an early calcite with larger (>1mm) grain-size and cloudy-spongy appearance due to large amount of fl uid inclusions and a younger water-clear vein fi lling generation (fig. 3h). 5.2. fluid inclusions in calcite in the calcite infi llings of the “pyjama-style” pillows of the reszél hill quarry, the early spongy and the late water-clear calcite contain rarely liquid and vapour (l+v) two-phase primary inclusions with about 5–10 μm sizes (fig. 4d). the primary origin of inclusions is evidenced by their three dimensional and sometimes zoned distributions independently from cleavage planes. the vapour phase fi lls up about 5 vol.% of the inclusions on room temperature. there also are very small (<5 μm size) secondary l+v and l only inclusions in healed microfractures of calcite; these inclusions were excluded from microthermometric studies. primary fl uid inclusions in the water-clear calcite, in the spongy calcite and within the transition zone between the two calcite phases, homogenized into the liquid phase most commonly between 100 and 120°c (fig. 5). freezing measurements encountered problems of metastability in the inclusions, expressed by disappearance of the vapour phase and its late showings at around +1 to +2°c during fast melting of ice. the problem was overcome by careful stretching of inclusions prior to the freezing runs. the eutectic temperature determined on the artifi cially stretched inclusions were around –20.8°c, suggesting a nacl–h2o type model composition. ice melting temperatures correspond to salinities of 3.2 and 4.6 wt.% nacl equiv. wt. % (fig. 5.). fluid inclusion studies were carried out from calcite from the amygdales and the feeding channels of the closely packed pillows facies from the mély valley quarry. primary l+v fl uid inclusions about 5 vol.% v phase on room temperature in the amygdales are about 5 μm in size (fig. 4h), and show steady decrease in the homogenization temperature from about 150°c at the rim to about 110°c at the centre of calcite infi lling (fig. 5). the eutectic temperature is between –20.5 and –22.1°c, while salinity also shows a decreasing trend from the rim (5.6 nacl eq. wt%) to the central zone (3.2 wt.% nacl equiv.wt.%). in the feeding channel, the homogenisation temperatures are slightly lower in comparison to amygdales, and they are between 80°c and 100°c. the eutectic temperature is between –20.4 and –21.1°c, while the mean salinity is around 3.9 wt% nacl equiv. wt% (fig. 5). 6. discussion the darnó unit is correlated with similar units of the nw-dinarides (pamić, 1997; dimitrijević et al., 2003) among which the kalnik mts. contain a well exposed submarine basaltic volcanic centre of triassic age in the hruškovec quarry. in the case of the subaqeous basalt lava-fl ow complex of the kalnik mts., six different facies were described by palinkaš et al. (1998, 2000, 2008). the major lava feeder in the centre of the low-aspect pseudo-cryptodome consists of coherent pillow lava facies which is laterally followed by closely packed pillows, “in situ” hyaloclastites, isolated pillow breccias, pillow fragment hyaloclastite breccias and peperitic hyaloclastites within red micritic limestone and red shale. in the darnó unit, there have been recognized only three of these submarine volcanic facies (closely packed pillow, peperitic pillow and pillow fragmented hyalocclastite breccia) in a large olistholite of the mónosbél complex. however, there is enough data which enable convincing correlation and comparison between the two triassic volcanic complexes. the exposed submarine volcanic facies in the darnó unit represent distal facies in relation to the master feeder zone, as deduced from the absence of coherent pillow lava facies, characteristic to the centre of the dome in the hruškovec quarry. this also invokes that cooling of lava was rapid, and this is manifested by sideromelane shards and skeletal plagioclase microcrysts in the basalt groundmass. amygdales rimming marginal parts of the pillow lobes evidence degassing in relatively shallow water, what enabled vesiculation of the basalt lava. the formation of the “pyjama-style” pillows and feeding channels invokes rapid cooling as well, due to subsequent precipitation of hydrothermal minerals in the space liberated by draining of lava from already solidifi ed crust of the pillow lobes. spherulites on the crust of the pillow lobes experienced slower cooling in the isolated mud environment, within the place of the pillows accommodation. physico-chemical characteristics of the hydrothermal water in the “pyjama-style” pillows were determined by fl uid inclusion microthermometry in calcite. vapour fi lm around the chilling basalt, supported by relatively high hydrostatic pressure, created low temperature hydrothermal fl uids. homogenization temperature of the uniformly fi lled primary fl uid inclusions (constant phase ratio), provided the minimum formation temperature of the host mineral. determination of the true formation temperature (trapping temperature) requires knowledge on concomitant pressure. estimation of pressure without an independent isotope or other geothermometer is just an approximation, and was done by the presence of the micritic limestone in the peperitic facies only. sedimentation of the limestone certainly took place above the carbonate compensation depth (ccd). the depth of the ccd is variable in the oceans in time and space. on the base of dsdp results, the ccd is known only till the jurassic back in time, and was about 4–4.5 km below the sea level (van andel tjeerd, 1975). balla et al. (1980) also appraise 4–4.5 km deep water for the basaltic volcanism of the darnó hill. a water colgeologia croatica geologia croatica 61/2–3 392 fi gu re 5: results of fl uid inclusion microthermometry carried out on samples from the reszél hill and mély valley, darnó unit. geologia croaticagabriella kiss et al.: volcanic facies and hydrothermal processes in triassic pillow basalts from the darnó unit, ne hungary 393 umn of 4 km exerts a pressure of 400 bars (40 mpa). using the estimate of the maximum pressure, the trapping temperature was determined by intercepts of this pressure with the isochors of fl uid inclusions. this approach gives negligible pressure corrections of homogenization temperatures in the range of 8–10°c. therefore calcite precipitation in the “pyjama-style” pillows took place at 110–140°c from hydrothermal solutions slightly more saline (3.2–4.6 wt.% nacl equiv. wt.%) than the sea water. this result excellently matches with the fl uid inclusions data for calcite in the “pyjama-style” pillows in the hruškovec lava-fl ow complex, where borojević et al. (2000) determined 110–160°c and 1.4–4.6 wt.% nacl equv.wt.% salinities. rapid cooling of heated sea water from about 160°c to 120°c is recorded by fl uid inclusions in amydales, followed by the lowest temperature (90–110°c) mineralization in the feeding channel in the closely packed pillow facies of the darnó unit. the rapid cooling process was associated with decreasing of salinities from 5.6 to 3.2 wt.% nacl equiv.wt.% in the amygdales. this decreasing trend is a result of the fl uidrock interaction. the loss of water due to formation of secondary hydrous silicates and retrograde dissolution of transient hydroxy-chloride phases may not substantially change salinity in an open system. in a restricted, semi-closed environment like vesicules, however, it may come in effect during early encrustation stage, and the lower (sea water) salinity is attained during recharge of the cooler sea water. fluid inclusion data on hydrothermal minerals formed in restricted, semi-closed environments, like amygdales are similar to some data from the hruškovec quarry, kalnik mts. (borojević et al., 2000). the discrepancies arise, however, with temperature and salinity data from open vein systems crosscutting pillow lava formation in the hruškovec lava-fl ow. salinities for that environment are in the range of 3–16 wt.% nacl equiv.wt.%, and presence of halite cubes in some rare fl uid inclusions in calcite (not measured due to decrepitation) indicates even higher salinities. temperatures as high as 300 °c were recorded for this stage of hydrothermal activity, invoking substantial magmatic heat source due to the vicinity to the central feeder zone. similar high temperature conditions could not be recognized in the hydrothermal environments of the darnó unit’s basalts which is consistent with their distal/peripheral position in the submarine volcanic system. 7. conclusions submarine basaltic blocks of triassic age enclosed in the olistrostrome of the monosbél complex of jurassic age, consist of closely packed pillow, peperitic pillow and pillow fragmented hyaloclastite breccia facies in the darnó unit, nehungary. this is also confi rmed by comparison of volcanic facies with those observed in the architecture of the well preserved subaqueous basalt lava-fl ow complex of triassic age in the hruškovec quarry, kalnik mts., nw-croatia. discovery of peperitic pillow facies in the submarine basalt formations of the darnó unit provides additional possibility for interpretation of the origin of magmatism. the pillow lava extrusion was on the bottom of the sediment fi lled basin and not on the ocean’s fl oor at a mid-ocean ridge because basaltic lava penetrated water soaked lime-mud existed above the ccd and this process resulted in the development of the peperitic facies. the intensive lava vesiculation recorded in the pillows also prefers shorter water column and lower hydrostatic pressure exerted on the lava. hydrothermal processes associated with the submarine volcanic activity resulted in formation of abundant calcite infi llings together with accessory chlorite, epidote, quartz, pyrite, hematite in amygdales, and vugs of pyjamas pillows and feeding channels in the centre of the pillows. temperature-salinity data (90–160°c, 3.2–5.6 wt.% nacl equiv.wt.%) from primary fl uid inclusions of calcite indicate that the hydrothermal processes also took place far from the master feeding zone of the extrusion where higher temperatures and salinities occur, as evidenced by data from the hruškovec quarry. decreasing temperatures and salinities from rim to core of calcite infi llings in amygdales suggest short-term interaction between the rapidly cooling lava and seawater in a semi-closed fl uidrock system. comparison of the obtained data between the darnó unit, ne-hungary and those on the hruškovec lava-fl ow of kalnik mts., nw-croatia, both situated in the zagorje-mid-transdanubian megaunit, a part of dinarides, with similar magmatic complexes along the dinarides, hellenides and even further to the east, would constrain more precisely timing of rifting and oceanization in the neotethyan evolution. acknowledgment this work was supported by the hungarian-croatian science and technology agreement project no. 07/cro to f. molnár and l. a. palinkaš and the otka (hnsf) t 49633 to f. molnár. special thanks to sibila borojević for discussions about fl uid inclusions in the kalnik mts. constructive comments from reviewers, s. kovács and b. lugović, highly improved the original version of this paper. references bakker, r.j. (2003): package fluids 1. new computer programs for the analysis of fl uid inclusion data and for modelling bulk fl uid properties.– chem. geol., 194, 3–23. balla, z., baksa, cs., földessy, j., havas, l. & szabó, i. (1980): the tectonic setting of the ophiolites in the bükk mountains (north hungary).– geol. carpath., 31, 465–493. borojević, s., palinkaš, l. a. & bermanec, v. (2000): fluid inclusions in pillow lavas of hruškovec, mt. kalnik.–proceedings, 2nd croatian geological congress, cavtat–dubrovnik, 123–125. dimitrijević, m.n., dimitrijević, m.d., karamata, s., sudar, m., gerzina, n., kovács, s., dosztály, l., gulácsi, z., less, gy. & pelikán, p. (2003): olistostrome/mélanges – an overview of the problems and preliminary comparison of such formations in yugoslavia and ne hungary.– slovak geological magazine, 9, 3–21. dosztály, l. & józsa, s. (1992): geochronological evaluation of mesozoic formations of darnó hill at recsk on the basis of radiolarians and k–ar age data.– acta geol. hung., 35, 371–393. dosztály, l., gulácsi, z. & kovács, s. (1998): stratigraphy of jurassic formations in northern hungary.– in: bérczi, i. & jámbor, á (eds.): stratigraphy of geological formations in hungary, 309–318 [in hungarian]. geologia croatica geologia croatica 61/2–3 394 downes, h., pantó, gy., árkai, p. & thirlwall, m.f. (1990): petrology and geochemistry of mesozoic igneous rocks, bükk mountains, hungary.– lithos, 24, 201–215. halamić, j. & goričan, š. (1995): triassic radiolarites from mt. kalnik and medvednica (northwestern croatia).– geol. croat., 48/2, 129–146. harangi, sz., szabó, cs., józsa, s., szoldán, zs., árvasós, e., balla, m. & kubovics, i. (1996): mesozoic igneous suites in hungary: implications for genesis and tectonic settings in the northwestern part of tethys.– int. geol. rev., 38, 336–360. kovács, s., ebner, f., gawlick, h.j., pamić, j., haas, j., gaetani, m., castellaria, a., kräutner, h.g., karamata, s., krstić, b., sudar, m., mello, j., polák, m. & mioč, d. (2004): tectonostratigraphic terrane and paleoenvironment maps of the circum-pannonian region: maximum neotethyan spreading (middle jurassic) environments.– geol. inst. hungary. kovács, s., haas, j., molnár, f., józsa, s., gulácsi, z., dosz tály, l., kiss, g., kövér, s., ozsvárt, p., palinkaš, a.l., halamić, j., sudar, m., jovanović, d., djerić, n., migiros, g., papanikolaou, d. & tselepdis, v. (2008): reassessment of the mesozoic darno hill ophiolite complex (ne hungary) and comparison with the inner dinarides and inner hellenides – preliminary data.– földtani közlöny (bulletin of the hungarian geological society), in press. less, gy., mello, j. (ed.), elečko, m., kovács, s., pelikán, p., pentelényi, l., peregi, zs., pristaš, j., radócz, gy., szentpétery, i., vass, d., vozár, j. & vozárová, a. (2004): geological map of the gemer-bükk area, hung.– geol. inst. hungary. palinkaš, a.l., bermanec, v., vrkljan, m. & međimorec, s. (1998): pillow lavas of hruškovec, north croatia, rifting magmatism or dismembered ophiolitic sequence.– igcp–369, subp.2, final session, prague, 84–85. palinkaš, a.l., kolar-jurkovšek, t., borojević, s. & bermanec, v. (2000): triassic rifting magmatism within zagorjemid-transdanubian zone, examplifi ed by pillow lavas of hruškovec, mt. kalnik, n.croatia.– in: tomljenović et al. (eds.): pancardi 2000 meeting, dubrovnik, 1.–3.10.2000. geološke vijesti, 37, 98–99, zagreb. palinkaš, a.l., bermanec, v., borojević šoštarić, s., kolar jurkovšek, t., strmić palinkaš, s., molnar, f. & kniewald, g. (2008): volcanic facies analysis of a subaqueous basalt lava-fl ow complex at hruškovec, nw croatia – evidence of advanced rifting in the tethyan domain. – j. volcanol. geoth. res., doi: 10.1016/j.jvolgeores.2008.06.037. pamić, j. (1997): the northwesternmost outcrops of the dinaridic ophiolites: a case study of mt. kalnik (north croatia).– acta geol. hung., 40, 37–56. van andel tjeerd, h. (1975): mesosozoic/cenozioc calcite compensation depth and the global distribution of calcareous sediments.– earth planet. sci. lett., 26, 187–194. manuscript received march 11, 2008 revised manuscript accepted may 29, 2008 in memoriam sestanovic.indd on october 12, 2005 dr.sc. slobodan šestanović, a full professor at the faculty of civil engineering and architecture, university of split and member of the editorial board of journal “geologia croatica”, suddenly died. professor slobodan šestanović was born in 1945 in lumbarda, on the island of korčula, and he finished his elementary and highschool education in split. he graduated in geology at the geological department of the faculty of mining, geology and petroleum engineering of the university of zagreb in 1969, and for the next 10 years worked in civil engineering, finishing his m.sc. degree at the university in zagreb. in 1979 he joined the civil engineering faculty of the university of split, where he was awarded his phd thesis entitled “hydrogeological and hydrological investigations, usage for investigation of relationships in the karst area”, defended at the mining-geological faculty of the university of belgrade. during his long and successful career, professor šestanović taught basic geology courses and applied geology not only to students of civil engineering and architecture at his faculty, but also as a visiting professor at the university of zadar and university of urbino (italy), and a visiting scientist at the university of udine (italy). he has published 3 textbooks, printed in several editions from 1986 to 2003. his scientific work focused mainly on problems dealing with large geotechnical projects in areas composed of flysch deposits. professor slobodan šestanović was a member of the editorial board of the journal “geologia croatica” from 1995 to 2005, dealing with engineering-geological papers, both as a reviewer and as the contact with international reviewers. we are grateful to him not only for his work, but also for his joyousness in his editorial work for our journal. his death came much too early and means not only a substantial loss for croatian geological engineering but also for us. may he rest in peace! iznenada je 12. listopada 2005. u 60. godini života u splitu preminuo naš kolega i prijatelj, redoviti profesor građevinsko-arhitektonskoga fakulteta sveučilišta u splitu i član uredništva našega časopisa “geologia croatica”, prof.dr.sc. slobodan šestanović. prof.dr.sc. slobodan šestanović rođen je 30. listopada 1945. u lumbardi na otoku korčuli. osnovnu i srednju školu završio je u splitu, a studij geologije na geološkom odjelu rudarsko-geološko-naftnoga fakulteta sveučilišta u zagrebu 1969. nakon diplomiranja sljedećih 10 godina radio je u građevinarstvu i paralelno završio poslijediplomski studij na sveučilištu u zagrebu i magistrirao iz hidrogeologije akumulacije buško blato. od 1979. radio je na građevinskome fakultetu sveučilišta u splitu, gdje je izradio doktorsku disertaciju s temom “hidrogeološka i hidrološka istraživanja u funkciji izučavanja odnosa u kršu”, i obranio je 1981. na rudarsko-geološkom fakultetu univerziteta u beogradu. u sveučilišnoj karijeri prof.dr.sc. šestanović prošao je sve stupnjeve od asistenta do redovitoga profesora u trajnome zvanju, predavajući od općih geoloških predmeta do primijenjene geologije i geološkoga inženjerstva studentima građevinarstva i arhitekture na matičnom fakultetu u splitu. bio je i gostujući profesor na sveučilištu u zadru i u istituto di geologia applicata, facoltá di scienze matematiche, fiziche e naturali universitá degli studi di urbino, italia. nizom specijalističkih predavanja o problematici građenja u flišu bio je gostujući znanstvenik na dipartimento di geologia applicata, facoltá di ingegneria, univ. degli studi di udine, italia. autor je triju udžbenika: “osnove geologije i petrografije – primjena u građevinarstvu”, “osnove inženjerske geologije – primjena u graditelj geologia croatica 58/2 205–208 zagreb 2005 in memoriam prof.dr.sc. slobodan šestanović 1945–2005 206 geologia croatica 58/2 stvu” i “stijene litosfere”, tiskanih u više izdanja od 1986. do 2003. u početku znanstvenoga i stručnoga rada na građevinskome fakultetu u splitu unutar svojega opredjeljenja za geološko inženjerstvo podjednako se bavio hidrogeološkim i inženjerskogeološkim istraživanjima. kasnije se sve više usmjeravao na inženjersku geologiju, a posebice na geotehničke zahvate u flišnim naslagama, u čemu je stekao reputaciju eksperta i vodećeg inženjerskog geologa u hrvatskoj, cijenjenog i traženog i u susjednim zemljama. nemjerljiv je doprinos i velike su zasluge prof.dr.sc. šestanovića u približavanju i uvažavanju geologije i geološkoga inženjerstva u građevinskoj struci. tome je posvetio najveći dio svojega znanstveno–stručnoga i cjelokupnoga stvaralačkoga opusa, o čemu svjedoče ne samo publicirani radovi već i mnogobrojni realizirani elaborati, studije i projekti. bio je član više strukovnih društava, između ostalih nacionalne grupe za inženjersku geologiju hrvatskoga geološkoga društva, te međunarodne udruge za inženjersku geologiju (iaeg). bio je i višegodišnji član državnoga matičnoga povjerenstva za polje geoznanosti. posebno ističemo njegovo desetljetno članstvo u uredništvu našega časopisa, od 1995. (vol. 48/2) do 2005. (vol. 58/1). brinuo je o prispjelim manuskriptima geoinženjerskoga sadržaja bilo kao recenzent bilo kao osoba za vezu između časopisa i inozemnih recenzenata. zahvalni smo mu za to, ali i za njegovu radost da je mogao dati svoj obol u uređivanju časopisa. ne samo uredništvo časopisa “geologia croatica”, već i cjelokupna geološka i graditeljska znanost u hrvatskoj smrću prof.dr.sc. slobodana šestanovića izgubila je vrsnog stručnjaka i znanstvenika, dobrog i vedrog čovjeka, dragoga prijatelja i suradnika. hvala mu i vječni mu pokoj! za uredništvo ivo velić šestanović, s. & buić, i. (1970): novo suvremeno postrojenje za preradu kamena i pripremu betona u šibeniku.– građevinar, 22 (1970/12), 415–416, zagreb. šestanović, s. (1976): ugljen – nedovoljno iskorišten prirodni energetski izvor dalmacije.– privreda dalmacije, 13/3, 37–40, split. šestanović, s. (1976): energetski resursi dalmacije s osvrtom na potrebu štednje i razumno korištenje električne energije.– privreda dalmacije, 13/6, 7–11, split. buličić, a., vukanac, d., brničević, b. & šestanović, s. (1977): ekonomski položaj i realizacija programa razvoja aluminijske industrije dalmacije.– privreda dalmacije, 14/10, 4–21, split. šestanović, s. (1977): problematika hidroenergetskog sistema “orlovac” s aspekta gubitaka vode iz akumulacije buško blato.– privreda dalmacije, 14/11–12, 5–9, split. šestanović, s. (1978): osvrt na problematiku istraživanja, eksploatacije i prerade nemetalnih sirovina dalmacije.– privreda dalmacije, 15/8, 17–21, split. šestanović, s. (1979): mogućnost kvantitativnog definiranja vodopropusnosti akumulacije buško blato.– zbornik radova u povodu 40-te god. rgn fakulteta sveučilišta u zagrebu, 363–367, zagreb. šestanović, s. (1979): neki pravci razvojne orijentacije u istraživanju, eksploataciji i preradi mineralnih sirovina dalmacije za razdoblje od 1981. do 1985. godine.– privreda dalmacije, 16/1–2, 45–46, split. borić, b. & šestanović, s. (1979): pregled značajnijih mineralnih sirovina dalmacije.– privreda dalmacije, 16/1– 2, 4–6, split. šestanović, s. (1980): analiza vodnosti akumulacije buško blato.– zbornik vi. jug. simp. o hg i ig, 1, 269–275, portorož. šestanović, s. (1980): kvantitativno definiranje vodnih pojava u funkciji upoznavanja odnosa u kršu.– zbornik savjetovanja o naučnim i tehničko–tehnološkim istraživanjima u geologiji, rudarstvu i metalurgiji, 271–278, neum. čagalj, m., šestanović, s. & gotovac, b. (1980): temeljenje stambenog tornja u flišnoj sredini.– zbornik 5. jug. simp. o mehanici stijena i podzemnim radovima, 1, 317–323, split. šestanović, s. & mikelić, k. (1981): mogući postupak određivanja parametara hidrogeoloških značajki u području krša.– zbornik iii. znan. skupa “numeričke metode u tehnici”, 453–462, stubičke toplice. šestanović, s. (1982): jedna mogućnost definiranja kvantitativnih hidrogeoloških značajki u području krša.– zbornik vii. jug. simp. o hg i ig, 1, 155–160, novi sad. šestanović, s. (1982): moguća interpretacija kretanja podzemne vode u odvodnim zonama akumulacije buško blato.– zbornik x. jubilarnog kongr. geol. jug., 3, 321–340, budva. šestanović, s, andrić, m. & čagalj, m. (1982): o dodatnim inženjerskogeološkim i geofizičkim istražnim publications of slobodan šestanović 207in memoriam – prof.dr. slobodan šestanović radovima na lokaciji mertojak–split iii.– zbornik vii. jug. simp. o hg i ig, 2, 273–282, novi sad. dorić, v., lozić, i. & šestanović, s. (1982): prikaz projekta magistralne ceste br. 11 split–sinj, dionica bilice–dugopolje.– zbornik xi. kongr. saveza društava za puteve jug., 419–425, opatija. šestanović, s. (1983): o potrebi poznavanja hidroloških značajki kod hidrogeoloških istraživanja u kršu.– zbornik jug. simp. o inženjerskoj hidrologiji, 261–270, split. šestanović, s., čagalj, m. & biloš, t. (1984): neke značajke lapora u flišu istočnog dijela splita.– zbornik viii. jug. simp. o hg i ig, 2, 363–367, budva. šestanović, s., lozić, i., roje-bonacci, t. & čagalj, m. (1984): prilog nužnosti osnivanja geotehničkog katastra u splitu.– privreda dalmacije, 21/1, 47–48, split. šestanović, s., čagalj, m. & urli, m. (1984): geotehnički radovi za temeljenje stambenog naselja pujanke u splitu.– građevinar, 36/9, 371–376, zagreb. šestanović, s., margeta, j. & dorić, v. (1984): hidrogeološki aspekt rješavanja odvodnje sa cestovnih prometnica šireg područja splita.– zbornik viii. jug. simp. o hg i ig, 1, 461–467, budva. šestanović, s., čagalj, m., bošnjak, d., jakovljević, s. & samardžija, i. (1984): inženjerskogeološka i geofizička istraživanja područja uz trasu pristupnih cesta za most preko rijeke dubrovačke.– zbornik viii. jug. simp. o hg i ig, 2, 369–375, budva. filipović, b., šestanović, s. & dimitrijević, n. (1984): opće pretpostavke hidrogeološkog aspekta zaštite voda u kršu.– vodoprivreda, 16/1, 7–11, beograd. cvijanović, d., paskalov, t., prelogović, e., petrovski, d., ortolan, ž. & šestanović, s. (1984): definition des parametres seismiques de project pour le barrage de sidi yacoub en algerie.– conference internationale sur la microzonation seismique, 89–106, ech cheliff, algerie. roje-bonacci, t., čagalj, m., šestanović, s., dešković, ž. & samardžija, i. (1984): geotehničke osnove, projektiranje i tehnologija izvedbe željezničke pruge kroz split.– in: jašarević, i. (ed.): mehanika stijena, temeljenje i podzemni radovi s posebnim osvrtom na sanacijske zahvate. dmspr hrvatske i dit hrvatske, 112–128, zagreb. šestanović, s. (1985): graditeljski zahvati i zaštita voda u kršu.– simpozij “čovjek i krš 85”, kupres (objavljeno u publikaciji naš krš, xi/18–19, 33–38, sarajevo). šestanović, s. (1985): utjecaj građevinskih objekata izvan urbaniziranih područja na vodne resurse u kršu.– acta carsologica, xiv–xv, 239–244, ljubljana. roje-bonacci, t., šestanović, s. & čagalj, m. (1985): analiza odnosa jednoosne čvrstoće i postotka caco3 u flišnim naslagama.– zbornik 6. jug simp. o meh. stijena i podz. radovima, 1, 104–107, titovo velenje. margeta, j., dorić, v. & šestanović, s. (1985): izvedba odvodnje magistralne ceste u vodozaštitnom području izvorišta u kršu.– tehnika (naše građevinarstvo), 38/2, 145–151, beograd. bojanić, l., ivičić, d., šestanović, s. & bošnjak, d. (1986): uloga i značenje inženjerskogeoloških radova kod denivelacije pruge u splitu.– građevinar, 36/1, 337– 341, zagreb. šestanović, s., roje-bonacci, t., čagalj, m., dešković, ž. & samardžija, i. (1986): geotehnička analiza prometnica u širem području grada splita.– ceste i mostovi, 32/9, 337–341, zagreb. šestanović, s., čagalj, m., rehak-korlaet, n. & barčot, d. (1987): prikaz prve faze geotehničkih istraživanja za potrebe temeljenja stambenog naselja žnjan u splitu.– zbornik ix. jug simp. o hg i ig, 2, 183– 187, priština. samardžija, i., čagalj, m., šestanović, s. & barčot, d. (1987): inženjerskogeološka istraživanja i zaštita kosina u flišnim naslagama.– zbornik ix. jug. simp. o hg i ig, 2, 171–173, priština. čagalj, m., samardžija, i. & šestanović, s. (1987): projektiranje i izvođenje sidrenih konstrukcija s prednapregnutim sidrima kod dubokih usjeka.– in: jašarević, i. (ed.): geotehnička sidra i sidrene konstrukcije. dit zagreb, dmspr hrvatske i dtpk hrvatske, 201–211, zagreb. čagalj, m., šestanović, s., roje-bonacci, t. & samardžija, i. (1988): denivelacija željezničke pruge u staroj gradskoj jezgri splita.– zbornik i. jug. simp. o tunelima, 229–236, brijuni. šestanović, s. (1989): inženjerskogeološka istraživanja fliša u istočnim stambenim naseljima splita.– rgn zbornik, 1, 69–76, zagreb. šestanović, s., barčot, d. & čagalj, m. (1989): rqd in thin-layered beddings.– geol. vjesnik, 42, 281– 286, zagreb. šestanović, s., samardžija, i., čagalj, m. & barčot, d. (1989): neki problemi rješavanja stabilnosti kosina u flišnim naslagama.– zbornik 7. jug. simp. za meh. stijena i podz. radove, 109–111, beograd. šestanović, s. (1992): arhitektonsko–građevni kamen, tehnički kamen i ostali prirodni građevni materijali dalmacije.– zbornik seminara “pretvorba vlasništva, restrukturiranje građevinske operative i perspektive buduće izgradnje”. sveučilište u splitu, 73–76, split. šestanović, s. (1992): geologija i petrografija u obrazovanju građevinara.– građevinar, 44/7, 475–477, zagreb. šestanović, s. & dragović, m. (1992): problemi primjene arhitektonsko–građevnoga kamena u obnovi dalmacije.– zbornik radnog sabora “graditelji u obnovi hrvatske”, dhgk, ii, 341–344, brijuni. braun, k., šestanović, s., barčot, d. & samardžija, i. (1992): inženjerskogeološke i strukturološke značajke u funkciji dokazivanja stabilnosti visokih zasjeka u čvrstim stijenama na primjeru dionice poluautoceste mc–11 solin–klis.– rgn zbornik, 4, 59–66, zagreb. šestanović, s. (1993): osvrt na inženjerskogeološke istraživačke radove u funkciji prostornog planiranja.– zbornik znanstveno–stručnog skupa “pravci razvoja hrvatske zajednice herceg–bosna”, sveučilište u mostaru, 115– 120, neum. 208 geologia croatica 58/2 šestanović, s., braun, k. & barčot, d. (1993): inženjerskogeološke značajke trase prometnice solin–klis (dalmacija–hrvatska).– rgn zbornik 5, 87–97, zagreb. šestanović, s. & štambuk, n. (1993): oštećene kamene crkve i sakralni objekti u splitsko–makarskoj nadbiskupiji.– klesarstvo i graditeljstvo, 1–2/iv, 15–16, pučišća. štambuk, n., šestanović, s. & dragović, m. (1993): učimo o kamenu naših starih i nas samih!– klesarstvo i graditeljstvo, 1–2/iv, 28–30, pučišća. dragović, m., štambuk, n. & šestanović, s. (1993): termofizička svojstva kamena kod suvremenih postupaka primjene.– klesarstvo i graditeljstvo, 1–2/iv, 34–38, pučišća. roje-bonacci, t., šestanović, s. & miščević, p. (1993): geotechnical problems encountered in road construction in the karst areas in dalmatia (croatia).– rgn zbornik, 5, 79–85, zagreb. šestanović, s. (1994): polazne osnove metodologije istraživanja za ceste u terenima dalmacije.– zbornik znanstveno-stručnog skupa “geotehnika prometnih građevina”, igh, 127–131, zagreb. šestanović, s. (1994): prikaz knjige o. bonaccija: “oborine – glavna ulazna veličina u hidrološki ciklus”.– rgn zbornik, 6, 167–168, zagreb. šestanović, s., štambuk, n. & samardžija, i. (1994): control of the stability and protection of cut slopes in flysch.– geol. croat., 47/1, 139–148. šestanović, s. (1995): inženjerskogeološke značajke fliša srednje dalmacije.– zbornik radova 1. hrvatskog geološkog kongresa, 2, 575–579, opatija. šestanović, s. (1995): prikaz knjige t. roje-bonacci: mehanika tla.– rgn zbornik, 7, 149–150, zagreb. šestanović, s., roda, c. & andrić, m. (1995): proposal for methodology to be applied to road construction in the karstified carbonate and clastic (flysch) terrains in southern croatia.– rgn zbornik, 7, 29–36, zagreb. šestanović, s., roda, c. & andrić, m. (1996): prijedlog metodologije istraživanja za cestovne prometnice u okršenim karbonatnim i klastičnim (flišnim) terenima južne hrvatske.– ceste i mostovi, 11–12, 273–278, zagreb. šestanović, s. (1998): engineering-geological characteristics of marl from eocene flysch in the city of split.– proc. 2nd int. symp. hard soils–soft rocks, 311–314, napoli. šestanović, s. (1998): prikaz knjige t. roje bonacci i p. miščevića “temeljenje”.– rgn zbornik, 10, 137, zagreb. šestanović, s. & barčot, d. (1998): engineeringgeological characteristics of the landslide mlija and their impact on engineering structures (omiš, southern croatia).– rgn zbornik, 10, 89–95, zagreb. šestanović, s. (1999): charatteristiche geotecniche dei terreni del flysch nell’area di split (dalmazia, croazia).– vol. collettaneo del xx convegno nazionale di geotecnica, 279–285, parma. štambuk cvitanović, n. & šestanović, s. (1999): nedestruktivna ispitivanja na kamenim konstrukcijama uporabom numeričkog modeliranja.– klesarstvo i graditeljstvo, x/1–2, 83–88, pučišća. štambuk cvitanović, n. & šestanović, s. (1999): numerical modelling as non-destructive method for the analyses and diagnosis of stone structures: models and possibilities.– rgn zbornik, 11, 53–60, zagreb. šestanović, s. & sakač, k. (2000): inženjerskogeološke značajke brda marjan (split, hrvatska).– zbornik radova 2. hrvatskog geološkog kongresa, 575–579, zagreb. barčot, d., grabovac, i. & šestanović, s. (2000): inženjerskogeološke i geotehničke značajke obilaznice ploča.– rgn zbornik, 12, 37–43, zagreb. jurak, v. & šestanović, s. (2000): hidrogeološki i inženjerskogeološki prikaz odabranih lokaliteta u području dubrovačkog primorja – postaja 3: most preko rijeke dubrovačke.– vodič ekskurzija 2. hrvatskog geološkog kongresa, 25–29, zagreb. sakač, k. & šestanović, s. (2001): osnovne značajke geološke građe marjana.– in: lozić, i. (ed.): marjane, naš marjane. marjan – društvo za unapređenje marjana, 41–47, split. šestanović, s. (2002): značenje suvremene inženjerskogeološke karte u geotehničkim istraživanjima.– zbornik simpozija geotehnika kroz eurocode 7, 407–413, hvar. šestanović, s. & štambuk cvitanović, n. (2003): protection criteria of cut slopes in eocene flysch in dalmatia (croatia).– proc. int. conf. on fast slope movements – prediction and prevention for risk mitigation, 469–472, napoli. miščević, p., roje-bonacci, t. & šestanović, s. (2003): stability of slopes in thin layered soft rock on example of eocene flysch in region of dalmatia (cro).– proc. int. conf. on fast slope movements – prediction and prevention for risk mitigation, 367–370, napoli. džeba, t., vranješ, m., jović, v. & šestanović, s. (2003): zaslanjenje vodonosnika gabela polje.– zbornik simp. voda u kršu slivova cetine, neretve i trebišnjice, 399–410, neum. šestanović, s. (2004): primjena važnijih vrsta arhitektonsko-građevinskog kamena dalmacije.– konkam 2004, 4–6, split. grabovac, i. barčot, d., šestanović, s. & dečman, a. (2004): inženjerskogeološke značajke tunela “konjsko”.– rgn zbornik, 16, 21–29, zagreb. jurak, v. & šestanović, s. (2004): stop 6.2.: the bridge over the rijeka dubrovačka.– 32nd intern. geol. congress, florence – italy, field trip guide book – p53, 44–45, roma. šestanović, s., barčot, d. & dečman, a. (2005): špilje u hidrotehničkom tunelu “vela luka”.– 3. hrvatski geološki kongres, opatija, knjiga sažetaka, 245–246, zagreb. 1. introduction the vinodol valley, with its distinctive morphology, is also characterised by a very complex structural fabric (fig. 1). the upper palaeogene flysch deposits are found in a synclinal position and are compressed by the lower palaeogene and upper cretaceous carbonates. in this way a narrow valley is formed with a nw-se strike. the contacts between the flysch and carbonate rocks are mainly tectonic with a markedly developed reverse character of displacement. the carbonate rocks that separate vinodol from the sea, form an asymmetric anticline with a more steeply inclined north-eastern limb. the core of this anticline is composed of upper cretaceous (cenomanian) limestone and dolomite deposits, while limbs that are in contact with flysch, are formed of foraminiferal limestones of lower and partly middle palaeogene age (figs. 2 and 3). the north-eastern slopes of vinodol, also composed of upper cretaceous limestones and dolomites together with the palaeogene foraminiferal limestones, exhibit the more complex tectonic structure. in the north-western part of vinodol, in the area between kriæiπêe and tribalj, the slopes in fact comprise the more or less inclined southwestern limb of the cretaceous-palaeogene anticline. in the area to the southeast of tribalj, the north-eastern slope is stepped into vertical cliffs. these cliffs were formed by destruction of the crest of the cretaceouspalaeogene anticline that was overturned in a southtectonics of part of the vinodol valley within the model of the continental crust subduction ivan bla©kovi∆ westerly direction. the aforementioned anticline has a reverse fault contact with the palaeogene flysch of the vinodol valley. the folded structure of vinodol initially appears to be simple, but is complicated by numerous phenomena that have not yet been unambiguously explained (stache, 1889; kadi∆, 1913; kormos, 1914; koch, 1924; matou©ek, 1927; »ubrilovi∆, 1938; salopek, 1960). these are: the normal and reverse faults of dinaric strike found along the contacts between the carbonate rocks and flysch deposits; in the middle of the valley, the high relief of the drivenik hill composed of the upper cretaceous limestones, that crops out of the palaeogene flysch deposits; the anticlinally folded palaeogene foraminiferal limestones at humac hill (peak 107) that are also cropping out of the palaeogene flysch deposits and are connected to the outcrops of foraminiferal limestones in the kamenjak area and in the area to the east of the badanj ruin, and lead to the presumption (»ubrilovi∆, 1938) of secondary isoclinal folding within the flysch deposits. the already known, together with newly acquired data on the composition and structure of vinodol, lead to certain interpretations of the method and timing of structural formation and also of the palaeogeography of the area. the more detailed data are either given in illustrations or will be explained in the description of stratigraphic and structural characteristics of tectonic changes and palaeogeographic evolution. g eol. croat. 52/2 153 189 26 figs. 1 tab. zagreb 1999 key words: continental subduction, folds, faults, structural relations, vinodol, croatia. kljuëne rijeëi: kontinentalna subdukcija, bore, rasjedi, strukturni odnosi, vinodol, hrvatska. faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, hr-10000 zagreb, croatia. abstract the vinodol valley is analysed as an example of one of the united zones of shallow continental subduction. the structural analysis together with the interpretation of structural dynamics of the central part of the valley is performed in that sense. the structural model that accompanies the subduction process is constructed. these structures are found to be largely dependent on the subduction plane geometry. saæetak vinodol je razmatran kao primjer jedne od udruæenih zona plitke kontinentalne subdukcije. u tom smislu obavljena je u srediπnjem dijelu doline rekonstrukcija struktura i interpretacija njihovog postanka. izraen je i model prateêih struktura procesa subdukcije, koje velikim dijelom ovise o obliku plohe podvlaëenja. 154 geologia croatica 52/2 there follows a short list of the most important data. thin palaeocene limestones, with characteristics of kozina layers, were determined exclusively on the north-eastern side of vinodol (kadi∆ et al., 1912; »ubrilovi∆, 1938). the broadness of the area of the vinodol palaeogene flysch deposits changes in a step-like manner. in the part between kriæiπêe and drivenik the zone is 350750 m wide, it broadens up in the area of drivenik and tribalj where it reaches close to 1,500 m. to the southeast of the line sopalj-baπunje there is an abrupt increase and the zone reaches 2,250 -2,500 m in width. the palaeogene clastic sediments in vinodol valley can be subdivided into two units. the older one, continuously distributed throughout the whole valley, is the flysch complex of middle to upper eocene age (grimani et al., 1973). the younger unit is represented by more coarse-grained clastics conglomeratic-sandy-marly sediments that were determined in the area south-east of drivenik, in ravines named vitra and pihlja and also along the antovo-belgradgriæane line (bla©kovi∆ & ti©ljar, 1983). the more complicated tectonic relations are confirmed by findings of the younger unit of flysch sandstones in the cretaceous-palaeogene limestones of the north-eastern margin of the valley (pihlja and vitra), and by the deep ingression of flysch deposits in the diran area, to the east of tribalj. the upper pliocene sediments are found in areas of the most intense tectonics where they were preserved from erosional processes (koch, 1922; »ubrilovi∆, 1938). observance of the reverse fault contact between the palaeogene limestones and the upper pliocene clastics in the area of the badanj ruin (bla©kovi∆, 1983) indicates the time of tectonic events and character of faulting. fig. 1 geographic-geological map (simplified after ©u©njar et al., 1970). legend: 1) upper palaeozoic clastics; 2) amphybolic porphyrite; 3) upper triassic dolomite; 4) jurassic limestones and dolomites; 5) cretaceous limestones, dolomites and breccias; 6) palaeogene foraminiferal limestones; 7) eocene flysch; 8) quaternary sediments; 9) normal contact; 10) transgressive contact; 11) fault; 12) reverse fault. sl. 1 geografsko-geoloπka poloæajna karta (pojednostavljeno prema ©u©njar et al., 1970). legenda: 1) klastiti mlaeg paleozoika; 2) amfibolski porfirit; 3) gornjotrijaski dolomit; 4) vapnenci i dolomiti jurske starosti; 5) kredni vapnenci, dolomiti i breëe; 6) paleogenski foraminiferski vapnenci; 7) eocenski fliπ; 8) kvartarne taloæine; 9) normalna granica; 10) transgresivna granica; 11) rasjed; 12) reverzni rasjed. 155blaπkoviê: tectonics of part of the vinodol valley within the model of the continental crust subduction additional data for reconstruction of tectonic activity are found in the thickness, hypsometric level and position of quaternary rockfall breccias along both margins of the valley. the tectonic elements also highlight the structural complexity. the opposite vergence of the basic structural units in vinodol is clearly observable, as well as vergence of the reverse faults within the vinodol valley itself. 2. stratigraphic and structural characteristics of the explored area the north-eastern side of vinodol, is characterised by the complexity of tectonic framework (fig. 4). along part of the slope between the kriæiπêe and griæane the valley can be subdivided into semi-autonomous second-order structural units. their borders mostly coincide with the fault zones of the diagonal system (fig. 5). to the north-west of the ropci-dedomir fault (2) lies the kriæiπêe-petrinoviêi structural unit. the palaeogene and upper cretaceous limestones dipping in a sw direction, have a general characteristic that dip angle decreases north-easterly toward the plateau which makes a core of an asymmetric anticline. between the ropci-dedomir fault (2), and kozak fault (3) lies the ropci-maliê structural unit. the slope mostly consists of strata dipping to the south-west. in a narrow strip of the highest cliffs on the north-east there is an abrupt change in shape of a flexural bend. it is characterised by very steep bedding planes with a dip range of 60 80°, some of them even in vertical position. the connected plateau is marked by differently positioned strata dipping in a north-easterly direction at angles between 20-25°. the flexural bend of strata becomes more and more expressed in the south-east, where it is also documented by metre-size structures (fig. 6a). the south-eastern extension of the flexure gradually passes into a synclinal structure that is partly preserved in the area called diran, namely in the reverse fault with a south-western vergence that has the same name. the carbonate sediment complex on the south-western side of the flexure (maliê hill, peak 298), has an anticlinal position (figs. 7 and 8). the third structural unit is named belgrad-griæane and lies on the eastern side of the reverse fault kozak (3). the unit is characterised by overturned strata of upper cretaceous and palaeogene limestones, forming an isoclinal anticline that is overturned toward the south-west. all three structural units are delimited by faults, mostly with reverse displacement. apart from the usual indications of the reverse character of faulting (fig. 10), some details observed in the vitra and pihlja localities deserve to be mentioned. in both of these gorges, coarse-grained sandstones and marls were found that pertain to the younger part of the palaeogene clastics and are compressed by a fault within the carbonate complex (fig. 4 cross-section j, fig. 9). these findings are located approximately 150 m higher than the highest point of the flysch deposits in the corresponding section of the valley. the common characteristic of the marginal faults of structural units (fig. 11), is their helicoidal shape (bla©kovi∆, 1997). the strike of the faults marks a sigmoidal contour. they have a dinaric strike on a plateau north-east of vinodol which passes into a diagonal one on the carbonate slope. two or more of the faults on the slope then merge into a single fault of dinaric strike that follows the contact between the carbonate complex and the vinodol flysch. the inclination of the fault planes changes accordingly, which facilitates their identification. from the initial vertical position, the fault planes gradually obtain a north-eastern dip while the reduction of the fault plane inclination is followed by more pronounced reverse faulting. the valley itself consists mostly of eocene flysch deposits. a typical sand-shale sequence comprises the older part of the flysch sediments, with marls as a dominant component, containing a rich fauna of large foraminifera. in the immediate vicinity of drivenik hill there is a rich littoral fauna with numerous specimens of anthozoans, echinoids, brachiopods, lamellibranchiats and gastropods (vogl, 1912). the younger part of the flysch-type sediments unconformably overlies the older sediments (bla©kovi∆ & ti©ljar, 1983). it is composed of conglomerates, conglomeratic and coarse-grained biocalcarenites and lithic arenites. these sediments have an autochthonous fossil fauna of gastropods and lamellibranchs. the younger part of the vinodol valley clastics is interpreted to be of upper eocene age. the tectonic setting of the older flysch sediments in vinodol is determined by marginal reverse faults, following the contact with carbonate rocks. the strata measured in the valley itself serve as the basis for reconstruction of folded structures ranging from upright to isoclinal folds. the morphological and geological significance of vinodol is represented by marked solitary uplifts, either of upper cretaceous limestones (drivenik hill) or of foraminiferal limestones (humac hill, peak 101 east of tribalj), that are found in the partially peneplaned flysch terrain. in the kamenjak and badanj areas, the foraminiferal limestones also appear in the cores of anticlines. drivenik hill mostly consists of upper cretaceous rudist limestones and is encircled by eocene flysch deposits (fig. 12). it is interpreted as an anticlinal structure marked by the tectonic elements and basal transgressive palaeogene breccias on both the south-western and north-eastern slope of the hill. together with a very rich fossil community in the older part of the flysch deposits that was identified as characteristic of the lit156 geologia croatica 52/2 fig. 2 geological map of part of vinodol between the kriæiπêe and griæane (after ©u©njar et al., 1970 partly modified). legend as in fig. 3. sl. 2 geoloπka karta dijela vinodola izmeu kriæiπêa i griæana (prema ©u©njar et al., 1970, dijelom dopunjeno). legenda: vidi sl. 3. 157blaπkoviê: tectonics of part of the vinodol valley within the model of the continental crust subduction toral environment (vogl, 1912), the reefal limestones and nummulite breccias of the younger part of the clastics (bla©kovi∆ & ti©ljar, 1983) that are found on the south-eastern slopes of the hill, speak in favour of its palaeogeographic uplift. the morphologically expressed humac uplift consists of foraminiferal limestones. it is surrounded by flysch deposits. based on the limestone strata measurements, a normal anticline is reconstructed (salopek, 1960). fig. 3 legend of the symbols and abbreviations used in geological maps, sketches and cross-sections. sl. 3 legenda simbola i oznaka na geoloπkim kartama, skicama i profilima. --, .­.--.. -1\ jt.:§ , , d ' i:::l ' d "', 0d, l,-~;_~ s...;r-. _b<.co \jppot ~ ..... dayi '*"'*': .....,.,.,. '*"" --,-­aw..bn j:...........,. • ............ .. " r , ...... _ ; .......... ' __ , " ... " ... _--e. ----....,.;..,-... _ ............ , .. 01.; ~ _j/fj>'j<j! -,..... --.-.,..' ••• ~.' ffl;_"imjorl.~ ~ .... "' ... """, ........ , ... -.,-, ... _ ... "'..". -~--• • $<0< ..... """' ........ ; __ pci<>ui"""":'_'_ .. -~ , , ...-. {oio .... ieoi.-...._ ~-.-8"-"1"'-._._1 u.,:.-..., _ ". " " , ,....-"d o ~ " f "'h , ~ , 11~': :))'jli . , , em , ffiffii "' ffi2l ~ , ffi2l ,m 158 geologia croatica 52/2 foraminiferal limestone outcrops surrounded by flysch sediments were determined in the area south-west of kamenjak. they were explained in the literature as a core of an overturned isoclinal anticline (»ubrilovi∆, 1938). near the badanj quarry, the foraminiferal limestones have the structural position of a core of an overturned isoclinal anticline (fig. 13). the clayey-silty sediments of pliocene age were determined in restricted areas of the south-western part of the valley (koch, 1922; »ubrilovi∆, 1938; bla©kovi∆, 1983). these sediments are mostly situated in areas of minor closed tectonic subsidence where they were protected from erosion. the quaternary rockfall breccias, in accordance to the intensity of the carbonate slope deformation, cover a larger area and are much thicker on the north-eastern margin of the vinodol. a structure of coarse oblique bedding is clearly observable at larger outcrops. the fig. 4 north-eastern slope of vinodol. the construction of the cross-sections a-n is adapted to the graphical possibilities of illustration. the helicoidal shapes of faults and the possibility of their merging into a single system are marked by raster. legend as in fig. 3. sl. 4 sjeveroistoëna padina vinodola. konstrukcija profila (a-n) kulisnog dijagrama prilagoena je grafiëkoj moguênosti prikaza. rasterom su oznaëeni helikoidalni oblici rasjednih ploha i prikazana moguênost njihovog stapanja u jedinstveni sustav. legenda: vidi sl. 3. 159blaπkoviê: tectonics of part of the vinodol valley within the model of the continental crust subduction rockfall breccias dip gently to the south-west, at an angle of 1520°. occasionally, in a much larger wild quarry (near franoviêi) the rockfall breccia layers are almost horizontal or very gently inclined in the direction of the valley, or even to the north-east. similar breccias along the south-western margin of the vinodol are less thick and are also found at a smaller number of localities. the coarse bedding is measured, with a north-eastern dip and inclination in the range of 38-44°. the prominent asymmetric ridge between the vinodol valley and the sea also has an asymmetric geological structure. the ridge is composed of upper cretaceous limestones and dolomites and of palaeogene foraminiferal limestones. structurally it is an asymmetfig. 5 schematic illustration of the separated structural units and marginal faults in the north-eastern part of vinodol. symbols as in fig. 3. sl. 5 shematski grafiëki prikaz izdvojenih strukturnih jedinica i graniënih rasjeda u sjeveroistoënom dijelu vinodola. znaëenje simbola vidi na sl. 3. fig. 6 photo-sketches of the structures in the upper cretaceous limestones and dolomites on the north-eastern vinodol slope, in the zebarrazromir area (cross-section h, fig. 4): a) structures of anticlinal bend (flexures); b) overturned anticline. sl. 6 fotoskice struktura unutar gornjokrednih vapnenaca i dolomita sjeveroistoënog oboda vinodola u predjelu zebar-razromir (profil h, sl. 4): a) strukture koljeniëastog savijanja (fleksure), i u zaleu b) prebaëena antiklinala. 160 geologia croatica 52/2 ric anticline with north-eastern vergence. the northeastern part of the structure (actually the north-eastern slope of the ridge) predominantly consists of foraminiferal limestones which form the south-western margin of the vinodol valley. the margin in its entire length follows a marked fault contact (the south-western vinodol fault 4) mostly between the foraminiferal limestones and the flysch of the valley (fig. 4). near the badanj quarry, on the griæane crikvenica road (fig. 14, sect. i, fig. 13) the convergence of two opposing structures can be observed; the south-western margin of the valley and the valley itself (fig. 13). the change in the inclination of the fault plane must be highlighted. the tectonic striations oriented in the dip direction determine the vertical tectonic displacement on the fault plane. the curvature of the fault plane is indicative for future considerations. the plane is most steeply inclined in its hypsometrically most elevated part (82°). while descending, the fault plane inclination becomes reduced to 50°. a small lateral shift of no more than 100 m would even give measurements close to 10°. following the south-western vinodol fault, the reverse fault contact is clearly observable in the foothills of the badanj ruin. along this contact, the foraminiferal limestones overlie the clayey-silty upper pliocene deposits (bla©kovi∆, 1983). in the area of the sopalj uplift, south-west of tribalj, some additional data have been recorded. sopalj is a prominent uplift, separated from the valley by steep cliffs (fig. 15). it appears to have shifted to the northeast, from the carbonate ridge that separates vinodol fig. 7 detailed geological map of the mahavice-kozak-maliê area. the merging of the faults is shown and a lateral transition of a flexure into an anticlinal structure. legend as in fig. 3. sl. 7 detaljna geoloπka karta predjela mahavice-kozakmaliê, s prikazom stapanja rasjeda i prijelaza fleksure u antiklinalnu strukturu. legenda: vidi sl. 3. 161blaπkoviê: tectonics of part of the vinodol valley within the model of the continental crust subduction from the sea, and in the valley. the uplift is bound by transverse faults and behind it, towards the sea, in the intersection of these fault zones, clayey-silty sediments were found. the aforementioned build-ups have the characteristics of fresh-water sediments. these rocks closely resemble the upper pliocene clayey-silty sediments found in the aforementioned vinodol localities. these transverse faults extend in the direction of tribalj, more precisely the janjevalj hamlet. the maximum thickness of the upper pliocene sediments is found in the zone between these two faults in the foothills of sopalj (koch, 1922). discordantly overlying flysch deposits, they were preserved in this setting due to convergence of synclinally placed flysch (layers with south-western dip) with the almost vertical plane of the south-western vinodol fault (4). a somewhat similar tectonic setting, namely the protrusion of part of a carbonate ridge separating the vinodol from the sea in the direction of the valley (marked by tectonic transport along transversal faults) is found in the area named graëiπêe (peak 289, fig. 12). consequently it is not only the eocene foraminiferal limestones that exhibit a direct fault contact with eocene flysch, but also the upper cretaceous rudist limestones. the fault plane of the south-western vinodol fault (4) generally dips toward the ne at angles between 5085°. the fault plane with south-western dip was found in two localities, the badanj ruin with a dip angle of 50° and the sopalj uplift where it has an angle of 72°. the changes in dip direction and angle of the fault plane are most commonly located close to the intersections with transverse and diagonal faults which disturbed the continuity of strike of the south-western vinodol fault. these characteristics of the geological composition and structure of certain vinodol areas provide the basis for the reconstruction of structural development; the distribution of chronostratigraphic units and of the timing of events. this reconstruction is given below based on a mobilistic approach where the vinodol is presumed to be one of the zones of shallow subduction of continental crust (a-type subduction) (herak, 1980; bla©kovi∆ & aljinovi∆, 1981; bla©kovi∆, 1991). 3. subduction model as a basis for structural development and its interpretation 3.1. fundamentals of the model the subduction model (fig. 16) is based on the analysis of microtectonic elements in the area of mt. ∆iêarija (bla©kovi∆ & aljinovi∆, 1981) as well as on the analysis of geological relations in a broader area, combined with the results of seismic survey (aljinovi∆ & bla©kovi∆, 1981). in this model, movement and subduction of a plate in direction of north-east (recent orientation) is postulated in such a way that it has a broader zone with domination of a horizontal displacement component, and a more narrow zone where the vertical component prevails (the subduction zone). the first phase of structural deformation (the collision phase) is characterised by folding of the sedimentary complex and formation of the areas of synclinal and anticlinal structures (bla©kovi∆ & aljinovi∆, 1981). in this phase, the morphology coincides with the structures. the continuation of displacement, followed by deformation of primary structures into more and more asymmetric folds (mostly of sw vergence), resulted in the formation of reverse dislocations. this is the beginning of the subduction process, primarily in less stable synclinal structures that are favourable for subsidence (fig. 17). fig. 8 series of parallel cross-sections in the mahavice-kozak-maliê area, the variation of folded and faulted structures in direction of strike is shown. legend as in fig. 3. sl. 8 niz paralelnih profila predjela mahavice-kozak-maliê s prikazom promjene boranih i rasjednih struktura po pruæanju. legenda: vidi sl. 3. 162 geologia croatica 52/2 characteristics in common. these are the mostly plicative deformations and domination of, predominantly concordant, shallow-marine sediments. the regular, zonal distribution of lithofacies is to be expected. the relatively passive section of continental crust is defined as the resistant (reaction) hanging wall r . in the initial phase this is the more stable, antiform structure that during the discontinuous subduction process provides the resistance. it is thus exposed to significant structural deformation of the plicative and especially of disjunctive characteristics, with a general uplifting trend. during sedimentation, this results in more frequent emersions, irregular distribution of lithofacies, confinement and reduced thickness of more varied lithofacies, as well as in a greater proportion of clastics, especially coarse clastic sediments. the notional more narrow zone of subduction s pertains to the relatively narrow contact belt separating the two plates (a and r) where their antagonistic vertical displacement takes place. this zone of active subduction corresponds to a primary unstable synform structure (syncline, synclinorium). the structural deformations in this zone, which occurred during periods of more intensive subduction, exhibit plicative and fault characteristics of compression, accompanied by pronounced horizontal and vertical lithofacies variation. clastic sediments characteristic of flysch deposits predominate together with those with mollase characteristics. fig. 9 detailed geological situation of the vitra and pihlja gorge area. legend as in fig. 3. sl. 9 detaljna geoloπka situacija predjela vitra i pihlja. legenda: vidi sl. 3. fig. 10 detailed sketch of folded and faulted structures in the area between the vitra and pihlja gorges. the character of the contact between the limestone complex of the north-eastern vinodol slope and the flysch deposits in the valley. legend as in fig. 3. sl. 10 skica detalja boranih i rasjednih struktura u predjelu izmeu vitre i pihlje, te karakter kontakta vapnenaëkog kompleksa sjeveroistoëne padine vinodola i fliπnih naslaga doline. legenda: vidi sl. 3. the active section of continental crust that moves horizontally and subducts is defined as the action foot wall a, that has particular general structural and facial 163blaπkoviê: tectonics of part of the vinodol valley within the model of the continental crust subduction 3.2. application and development of the model to the vinodol area the area of the vinodol valley, being one of the more prominent zones of shallow subduction, contains the majority of underthrusting (shallow subduction) characteristics of a broader area on a small scale. the characteristics of such underthrusting are shown in fig. 17. the tectonic subdivision of vinodol is also performed in accordance with the subduction model. the carbonate ridge between the vinodol and the sea is thus defined as the marginal part of the action footwall a, the north-eastern carbonate slopes of vinodol as part of the resistant (reaction) hanging wall r, and the valley itself, mostly filled with flysch, as the more narrow zone of subduction s. the initial collision movements happened in the laramian tectonic phase by the end of cretaceous (fig. 17, i). gentle folds were formed, providing conditions for emersion, respectfully for the deposition of kozina limestones and their facies equivalents in the deepest parts of the palaeorelief, i.e. in the synclinal structures (phase i). the period of comparatively stable deposition of foraminiferal limestones is excluded here. the interval of intense clastic deposition is further encompassed by the scheme (fig. 17, ii). the subduction process continues. in the narrow zone of subduction (s), the intensification of subduction causes counterclockwise rotation on the horizontal axis. the marginal part of the action footwall (a), in shape of an anticline or a monocline, is subsided and subducted, while the opposing anticlinal structure, part of the resistant (reaction) hanging wall (r), undergoes a gradual uplift. the result of this opposing movement is observable in the shifting of the syncline axis (axis of the narrow zone of subduction) in a direction opposite to the main movement, which is reflected in the asymmetric distribution of the kozina layers. the continuation and intensification of the subduction process influences the predominantly clastic deposition. changes in depositional environment result in various lithofacies (flysch, promina formation, and jelar formation). the final phase (fig. 17, iii) is connected to phase ii. according to the data in the study area, there is probably a time-link between this phase and deposition of the jelar-layers and also with later deposition of the quaternary rockfall breccias. this phase is also recently active, when discontinuous but intensive underthrusting is assumed. the result of the subduction process is reflected in the significant width reduction of the narrow zone of subduction (s), and in the intensive structural deformation of rocks in both this zone and the neighbouring ones (a and r). within the zones, deformation is not identical across the zones, and the differing character and intensity is shown by examples from the studied area. they primarily depend on the older structures, physical characteristics of the rock and on the mode of tectonic displacement. the action footwall complex (a) is mostly exposed to plicative deformations whereby folds with vergence in the direction of movement are formed, and also occasionally those with the opposite vergence of both the folds and reverse faults. on the contact with the zone of subduction (s), an anticline is formed. in some cases a monocline can be formed instead (fig. 17, alternative iiia). the more narrow zone of subduction (s) with a clastic complex is exposed to the action of two opposing forces. part of the subduction zone sedimentary complex is being underthrusted together with the rocks of the action footwall. due to the width reduction, the fig. 11 helicoidal shapes of the fault planes (a) and the faults merging into a single fault (b) (bla©kovi∆, 1997). sl. 11 helikoidalni oblici rasjednih ploha (a) i stapanje rasjeda u jedinstvene rasjede (b) (bla©kovi∆, 1997). 164 geologia croatica 52/2 higher parts of the sedimentary complex are pushed up, accompanied by formation of various secondary tangential structures. the vergence of structures is mostly opposite to the direction of the main movement. the elevation of this part of the complex is asymmetric and, is especially well expressed along the contact with rocks of the resistant (reaction) hanging wall (r). the zone of the reaction hanging wall (r) resists the horizontal component of the main movement, and becomes an area of uplift characterised by intense tangential plicative and, especially disjunctive deformation. as a rule, the vergence of structures is opposite to the direction of the main movement. the borders between the aforementioned zones (a s r), in this case separating the anticlinal from synclinal structures, are mostly tectonic contacts. they all have a characteristic shape of the fault planes, which in a vertical section look more or less like a stretched invertfig. 12 detailed geological map and cross-section of the graëiπêe-drivenik area. legend as in fig. 3. sl. 12 detaljna geoloπka karta i profil predjela graëiπêe-drivenik. legenda: vidi sl. 3. 165blaπkoviê: tectonics of part of the vinodol valley within the model of the continental crust subduction ed picture of a letter “s” (bla©kovi∆ & aljinovi∆, 1981). due to compression, in final consequence, they all exhibit a reverse character of displacement. 4. interpretation of the structural evolution of the area of vinodol the asymmetric ridge separating the vinodol valley from the sea is interpreted as the marginal part of the action footwall (a) that belongs to the transitional zone between the horizontal and vertical component of movement, i.e. the subduction itself. interpretation of this direction of movement is corroborated by the shift of the part of the ridge towards the vinodol valley along the diagonal faults (peak 327, the sopalj uplift). an attempt to simulate the tectonic evolution of such a structure (fig. 18) illustrates the character of movement, and gives an explanation of the distribution and position of dominant open fissures on the ridge. it also explains the change in dip angle of the plane of the south-western vinodol fault (4) on the contact with the upper pliocene clastic deposits in the valley itself. the subduction is accompanied by rotation which causes the relative uplift of the ridge and subsidence of the contact part of the clastic sediments in the more narrow zone of subduction (s) i.e. in the valley. the vertical displacement is confirmed by findings of the timeequivalent upper pliocene sediments at different altitudes. behind the sopalj uplift they are located 225 m above the sea-level, and on the foothills of the same carbonate ridge on the valley-side at 100-155 m. the geological situation and reconstruction of the primary conditions is illustrated in fig. 19. the south-western margin of the vinodol is interpreted as a contact zone between the action footwall (a) and the more narrow zone of subduction (s). its field expression is found in the south-western vinodol fault (4). the most important structural changes are connected to this fault. the dip angle of the helicoidal plane of the southwestern vinodol fault (4) varies from 48° in the northeast, through the vertical position and is finally overturned, dipping at 50° toward the south-west. the angle of dip causes different structural deformations of rocks in the valley, i.e. in the more narrow zone of subduction (s) (figs. 14 and 20). the gentle dip of a fault plane, in a north-eastern direction, produces relative uplift of the hanging wall where the older rocks crop out (west of piline). there are no traces of more extensive deformations of flysch deposits in the north-eastern extension of the cross-section. the steeper dip of a fault plane, between the 65° and 80°, that is characteristic for a major part of the south-western vinodol margin, marks the contact between the palaeogene limestones and flysch deposits. the more significant horizontal extent of plicative deformations in the flysch deposits of the valley is presumed here. the vertical, or nearly vertical, position of the fault plane (near podsopalj) influences the anticlinal formation, with contemporary relative uplift, of the hanging wall rock complex, namely a tectonic block in direction of compression. it also causes the more pronounced folding of a larger horizontal extent. the steeply overturned position of a fault plane (the sopalj peak, fig. 19) causes both the synclinal bend and the more intense subsidence of the flysch and younger sediments (pliocene). this increases the potential for their preservation from erosion. the deeper subsidence along the south-western fault is compensated by secondary folding of the flysch deposits of a broader area in the direction of the cross-section line, and, partly by the uplift and anticlinal formation of the foraminiferal limestones (the humac hill, peak 104). the more gentle dip of the overturned fault plane, partly inferred in the area of the graëiπêe-drivenik cross-section (fig. 12) and determined in the area of the badanj quarry as 30° overturned (fig. 14), corresponds to the more significant structural changes in a smaller area, but with bigger vertical extent. a tectonically bounded structure is formed where the rocks of the fig. 13 detailed geological map and cross-section of the badanj quarry on the road crikvenica-griæane. legend as in fig. 3. sl. 13 detaljna geoloπka karta i profil okolice kamenoloma badanj uz cestu crikvenica-griæane. legenda: vidi sl. 3. 166 geologia croatica 52/2 fig. 14 south-western vinodol fault. the helicoidal shapes of the fault planes are marked by raster. the construction of the cross-sections i-viii is adapted to the graphical possibilities of illustration. legend as in fig. 3. sl. 14 jugozapadni vinodolski rasjed rasterom oznaëeni helikoidalni oblici rasjednih ploha. konstrukcija profila (i-viii) kulisnog dijagrama prilagoena je grafiëkoj moguênosti prikaza. legenda: vidi sl. 3. ii • .. -... .., • .~::_c'""'c .. ~-_~-... --_ n 167blaπkoviê: tectonics of part of the vinodol valley within the model of the continental crust subduction basement of flysch complex, i.e. the palaeogene foraminiferal limestones (in the badanj quarry) or even of older, upper cretaceous limestones, crop out. they for med as a consequence of a deeper penetration of the stress caused by subduction, transferred by the position and inclination of the fault plane. an alternative method of formation of such structures is due to inherited positive and negative palaeostructures that influenced the final shape of structures. an example of this kind of structure is found on drivenik hill. fig. 15 geomorphological (a) and geological (b) situation in the kaëjak-tribalj area. legend as in fig. 3. sl. 15 geomorfoloπka (a) i geoloπka situacija (b) predjela kaëjak-tribalj. legenda: vidi sl. 3. a b fig. 16 the united subduction zone model (bla©kovi∆ & aljinovi∆, 1981). sl. 16 model udruæenih zona podvlaëenja (bla©kovi∆ & aljinovi∆, 1981). 168 geologia croatica 52/2 fig. 17 stages in development of the vinodol subduction zone and the accompanying manifestations (the fault character is defined on the position of the hanging wall and footwall). sl. 17 stadiji razvoja zone podvlaëenja u vinodolu i popratne manifestacije procesa (definiranje karaktera rasjeda je prema poziciji krila). = -'--._._­---.• '----------_._.. -"-.,--..::...._ .. "=-­-------= --• • , f · ---, ----,--. ....-.-'0-···· '--,;----'­... _---­_._169blaπkoviê: tectonics of part of the vinodol valley within the model of the continental crust subduction fig. 18 explanation of the destruction process along the diagonal faults, affecting an anticlinal structure in the kaëjak-sopalj area (see fig. 15). sl. 18 objaπnjenje procesa destrukcije antiklinalne strukture uz dijagonalne rasjede, na podruëju kaëjak-sopalj (vidi sl. 15). narrowing of the structures is characterised by more intense deformations, occurring because of the reduction of inclination of the overturned fault plane, e.g. as observed at the badanj quarry (fig. 14). this can go as far as clutching of the synclinally formed flysch deposits and the establishment of a tectonic contact between the foraminiferal limestones of the two anticlinal structures with opposing vergences (fig. 20, inferred section). the real situation of such a cross-section is found in the area of the vitra gorge on the north-eastern slope of vinodol (fig. 4, sections j and k). this path of tectonic evolution can be explained by folding and faulting within the scope of the subduction process (fig. 21). the terrain recognition of faults and determination of structures can be very difficult in such a case, because the tectonic contact can be formed between the two limbs with similar orientation that belong to the two different, but originally parallel anticlinal structures. based on the discussed examples, certain conclusions of a broader significance can be drawn. depending on the shape of the longitudinal fault planes, namely on the inclination of the relevant part of the plane, which can vary significantly along the strike, and also on the physical characteristics of the contact rocks as well as on the character of the main movement, differently shaped secondary structural deformations will be formed in the more narrow zone of subduction (s), characterised by differences in both the horizontal extent and vertical reach. these structures are rarely found in the action footwall (a) for it acts as a structurally united complex, dislocated in blocks only by the transverse and diagonal faults. by analysis of variation in the dip direction and angle of the relevant part of the fault plane having the same characteristic shape, and with mostly similar resulting force of the rotationary subduction of the action footwall (a), a supposed model of deformation can be constructed (fig. 20). it can be observed from the model that by an increase in the inclination of the fault plane segment to the vertical position, the deformations in the more narrow zone of subduction (s) are intensified in respect to the shape of structures, the width of the deformed complex as well as its depth or thickness. a further inclination “increase” over the 90° (in the overturned part of the segment, where the dip direction changes and angle is reduced), causes an increase of the intensity of structural changes in respect to the shape and vertical reach, but at the same time with marked reduction of their horizontal extent. within the more narrow zone of subduction (s), along the strike of the bordering longitudinal fault, the structures with different characteristics and extension would have had the continuous evolutionary path were it not for the numerous transverse and diagonal faults. these, mostly radial, faults (as a rule with horizontal displacement) that cut through the primary structures (a and r) or through their parts, are formed as a consequence of subduction. taking into account a certain degree of autonomy in the movement and reaction of the rocks in marginal zones (a and r), the separate fault systems in the action footwall zone (a) and in the zone of the resistant hanging wall (r) are assumed. the central, more narrow zone of subduction (s) becomes the area of their interference. it is exactly because of displacement along such, mostly vertical, faults that the main subduction movements are intensified in their reach, together with significant contemporaneous change in the positions of the fault planes on the contact with the more narrow zone of subduction (s). 170 geologia croatica 52/2 the similar analysis and interpretation of the evolution and characteristics of structures in the contact area between the more narrow zone of subduction (s) and the resistant hanging wall (r), as well as within the hanging wall itself, i.e. in the flysch valley and on its north-eastern carbonate slope, isn’t entirely possible. although similar tectonic elements are encountered here, differences also exist, the most important of which is the inhomogeneity of the fault contact and various intensity of tectonic deformation, producing alternative shapes of structural deformations and their different vertical and horizontal extent. these differences primarily resulted from the palaeostructural and consequent palaeogeomorphological high relief of what initially appeared to be a united complex consisting of the resistant hanging wall (r) and the more narrow zone of subduction (s). data suggests that the initial folded structures existed within the tectonically narrowed flysch valley and carbonate rocks on both of its sides (fig. 22). many examples of direct evidence can be given: the belgrad-griæane structural unit is an overturned isoclinal anticline; in the diran area, partly with synclinal structure, the flysch layers are drawn deep into the carbonate rocks; on the maliê uplift, the foraminiferal limestones strata have an anticlinal shape; in the vitra and pihlja gorges a younger unit of eocene clastics is found; the upper cretaceous anticline is to the west of vitra; the upper cretaceous and foraminiferal limestones of drivenik hill, primarily an anticlinal structure, are fig. 19 pliocene sediments: a) the hypsometric and structural position of pliocene sediments in the sopalj area; b) inferred palaeogeographical and palaeostructural relations of the sopalj area in the upper pliocene. legend as in fig. 3. sl. 19 pliocenske naslage: a) hipsometrijski i strukturni poloæaj pliocenskih naslaga u predjelu sopalj; b) pretpostavljeni paleogeografski i paleostrukturni odnosi u gornjem pliocenu u predjelu sopalj. legenda: vidi sl. 3. 1 7 1 b laπk o v iê: t ecto n ics o f p art o f th e v in o d o l v alley w ith in th e m o d el o f th e c o n tin en tal c ru st s u b d u ctio n iwji.:!i" i'linfi tp,..r;~~~ ~i:~fqilj,~ /\c'iki!i" -~ ~~" .. :.~~""".. ... .....,.i~ :::=::r~=-~ ~ or!enoo"jiln ih'je rm tiiiu!:wf,i.tui, ~ .s~ ~=i , :j'i( ==ft=~ 100 .:n ~= u! ftod. j il'&~"~w. oum.tt ... tn'e'r,i;i,ltmj'e 0, ~rame \lejm:;l4.r.w3e. fswhge-~ 1'1\&(. j ri. i ,""l fig. 20 the fault plaue geometry and extent of deformation in the more nanow zone of subduction. legend of cross-sections in fig. 3. sl. 20 oblik rasjedne plohe i stupauj deformacija u uioj zoni subdukcije. legenda za profile: vidi sl. 3. exmiple . cross secllij/ts ~-pr.nfru f'm.t<=1te" i'\r. 1 q. 111 ol'.iiop.l&'. 14 1.1' ~ " -. , . , ... .-. \ . \ ...... tjilfl.ld....-!.c;;il-o:\'el1!:i\ 1'lt!l.u...l-t;ntlc'!.'ejlit:.t ~i 6t l!l s 15& tjilelloi.j i ii: h ..... -.-4 tl~ ---14 172 geologia croatica 52/2 surrounded by the synclinally shaped eocene flysch from both the eastern and western side; in the broader area of tribalj, anticlinal structures of foraminiferal limestones were determined (the humac hill, peak 102) as well as anticlines of carbonatemarly eocene sediments (near podsopalj). isoclinal folding explains the outcropping of foraminiferal limestone in the kamenjak area (»ubrilovi∆, 1938) together with those to the north-east from the badanj quarry. there are also the indirectly obtained data. the indicated synclines in the area between the pihlja and vitra gorges and in the extension of the diran area across the villages antovo, belgrad and griæane, contain the younger unit of eocene clastics. this location becomes logical if the synclinal structures are taken to have been palaeogeomorphological troughs in a certain time-interval, when they served as channels of intensive and directed transport of material. taking into account the discussed data, a synclinorial structural shape of a middle eocene flysch basin in the vinodol area can be presumed. a sequence of brachyanticlines and brachysynclines in parallel and partly in “en echelon” position is reconstructed. the noses of brachystructures are mostly not preserved. the southsouth-eastern parts are degraded by the rotationary subduction of the action footwall along the south-western vinodol fault (4) and the north-north-eastern noses of mostly synclinal structures are hidden by the tectonic contacts with the neighbouring anticlines. the schematic palinspastic reconstruction shows the distribution of brachystructures (fig. 23). the structures differing in the thickness of the flysch sediments are marked, as well as the areas with a supposed domination of carbonate rocks. the reconstruction is limited in the time-interval between the eocene flysch deposition and the deposition of the younger unit of coarse eocene clastics. if the distribution of primary plicative structures in subduction conditions and the reaction of the resistant hanging wall (r) and the connected part of the narrow zone of subduction (s), is taken as a starting-point (fig. 23), it enables the explanation of solitary structures. such an explanation has to account for the physical characteristics of clastic and carbonate rocks, and their susceptibility to a certain type of structural change as well as for the thickness of rock units and their initial structure. a thicker clastic complex with a structure of either one or many parallel synclines, exposed to the subduction movement in a direction perpendicular to the strike of structures, in contact with the more stable anticlinal carbonate complex of the resistant hanging wall (r), will result in the formation of a unique, simple tectonic contact. this contact will have a form of a gently inclined reverse fault or an overthrust, such as the kozak fault (3) that separates the belgrad-griæane structure from the widest flysch part of the valley. the opposite example, including a thinner clastic complex, is characterised by shallower synclines and is connected to the reverse tectonic contacts formed with steeply inclined to almost vertical fault planes, where the synclinal parts of structures lie in the footwall. a gradual transition exists between these two extreme cases, manifested in the gradual change of the reverse faults inclination and in their throw. in the case of “en echelon” distribution of the initial anticlinal noses in the direction of the synclinorial area, the merging of two or more faults into a single reverse fault is to be expected. alternatively, the nose closure of the synclinal structure can produce a reverse fault, which can pass into a vertical one, to gradually disappear or pass into a flexure that becomes less and less expressed in horizontal extension (fig. 7). fig. 21 model showing the closure of a synclinal structure and the reverse faulting in the course of the subduction process. sl. 21 model zatvaranja sinklinalne strukture i reverznog rasjedanja u procesu podvlaëenja. 173blaπkoviê: tectonics of part of the vinodol valley within the model of the continental crust subduction fig. 22 tectonic sketch of the vinodol valley study area, drawn according to the data on the basic geological map scale 1: 100,000 (sheet crikvenica), photogeological prospection, geomorphologic characteristics and a terrain reconnaissance. legend as in fig. 3. sl. 22 tektonska skica istraæivanog dijela vinodola, izraena prema podacima osnovne geoloπke karte, list crikvenica 1:100.000, fotogeoloπke prospekcije, geomorfoloπkih karakteristika i terenskog rekognosciranja. legenda: vidi sl. 3. 174 geologia croatica 52/2 in the valley of vinodol, the markedly asymmetric distribution of some chronostratigraphic units, structures and their hypsometric position, confirms the subduction of the south-western part of vinodol (a) and the upthrow of the north-eastern side (r). the upper pliocene sediments are located only along the south-western margin of vinodol. they can be found within the tectonically closed structures and mostly in their hypsometrically lowest parts. the tectonic contacts between the predominantly eocene flysch and carbonate rocks on the valley sides have different hypsometric positions. the contact is notably higher close to the reverse faults of the northeastern vinodol margin in respect to the contact along the reverse south-western vinodol fault (table 1). the quaternary rockfall breccias are also located along the same fault contacts (table 1). the minimal thickness (1-5 m) and distribution of breccias along the south-western vinodol fault (4), as well as the dip angle of the weakly expressed layers (38 -44°, fig. 24a), are a consequence of the partly rotational subduction of the south-western tectonic block the action footwall (a). the opposite side of the valley, close to the north-eastern faults, shows a greater thickness (1025 m) and spreading of the rockfall breccias. this reflects the intensity of tectonic changes and the character of displacement. the upthrow of the carbonate complex is accompanied by upthrow of the north-eastern part of the flysch valley complex. this is corroborated by the hypsometric position of the tectonic contact(-s) and especially by the dip angle (15-20°) of the quaternary rockfall breccias. the layers can also be horizontal or even gently dipping toward the north-east (fig. 24b). an illustration of the development of these relationships is shown in fig. 25. 5. structural evolution the initial deformations are placed in the frame of the laramian tectonic movements on the cretaceoustertiary boundary. these movements were an introduction to disintegration of the carbonate platform in this part of the dinarides. they caused the formation of gentle anticlinal and synclinal structures and a consequent relief together with emersion. the following mobility during part of the palaeocene is manifested in the lability of the more pronounced synclinal structures, and is documented by deposition of the kozina layers and similar sediments in depressions. foraminiferal limestone deposition represents the relatively calm time-period that mostly corresponds to the lower eocene. the deposition of clastic flysch sediments marks tectonic reactivation. this generally occurred in the fig. 23 schematic palinspastic illustration of folded structures in the initial phase of the pyrrenean tectonic movements. sl. 23 shematizirani palinspastiëki prikaz boranih struktura u poëetnoj fazi pirenejskih pokreta. 175blaπkoviê: tectonics of part of the vinodol valley within the model of the continental crust subduction lutetian, but in some areas was much earlier. the initial phase of this tectonic movement is interpreted as the continuation in plicative deformation of the existing fold structures. it is noted that the very subsidence of the unstable synclinal parts of folds had characteristics of subduction movement even in this initial phase. the subsidence of the unstable zone is asymmetric (the recent position of the kozina layers), causing the translation of the depositionary flysch basin maximal axis in a direction opposite to the main movement. the younger unit of conglomeratic-sandy deposits in vinodol unconformably overlies the flysch sediments (bla©kovi∆ & ti©ljar, 1983) and marks the preceedingly increased tectonic activity. this activity is found to have had a clearly expressed subduction movement the asymmetric upthrow of the anticlinal structure behind, i.e. of the resistant hanging wall r, and subsidence of the synclinal structures (more narrow zone of subduction s) followed by structural changes. the continuation of tectonic evolution can be traced in the data connected to the younger pliocene and quaternary sediments. downhill of the badanj ruin, the pliocene sediments have a reverse tectonic contact with the palaeogene foraminiferal limestones thus proving the post-pliocene tectonics. interpretation of the time, and especially of the character of tectonic movements, was facilitated by the discovery of upper pliocene deposits in a “doline” south-west of the sopalj uplift (peak 321) at an altitude of 225 m. the outcrops of the pliocene deposits in the valley (podsopalj) are at a level of 100 -155 m above the sea. the difference in hypsometric position is interpreted to be a consequence of the subsequent movements subsidence of the south-western part of the valtable 1 an overview of the above-sea-elevation of the flysch-limestone contact, active rockfalls and the thickness of the quaternary rockfall breccias on the margins of the vinodol valley. tablica 1 pregled nadmorske visine kontakta fliπ vapnenci, aktivnih sipara i debljine kvartarnih sipariπnih breëa uz rubove vinodola. 176 geologia croatica 52/2 ley accompanied by the uplift, asymmetric folding and transversal faulting of the cretaceous-palaeogene anticline between the vinodol and the sea. the mountain saddle that separates the two pliocene outcrops is 60 m higher than the pliocene deposits in the “doline” which means that post-pliocene asymmetric folding and uplift also took place. characteristics of the quaternary rockfall breccia, such as their composition, thickness, location and especially the structural peculiarities, provided data for reconstruction of quaternary tectonic activity. the interpretation of tectonic changes favours a constant character for the main movement (fig. 25). the lesser amount of the rockfall breccias along the south-western vinodol slope, together with their steep dip angle, confirm the rotationary movement in the subsidence of the action footwall (a), as well as the tendency of subsidence of the valley flysch deposits in the immediate vicinity of the contact. on the opposite valley side, in the narrow zone of contact, the upthrow of the north-eastern vinodol carbonate slope the resistant hanging wall (r), conditions the upthrow, or the “popup” of the plastic, mostly marly flysch deposits. consequently, the pop-up of the flysch bedrock caused the reduction in dip angle of the rockfall breccias. therefore, the most intensive tectonic movements occurred during the quaternary period, subsequent to deposition of the upper pliocene sediments. the presently active tectonic movements are manifested in the frequency of earthquakes, and in intensive erosion (in the slani potok area). their expression in the field is shown in fig. 26. 6. conclusion the paper has an emphasis on tectonic relations and reconstruction of tectonic evolution. the reconstruction is performed by means of the continental subduction processes. the vinodol area is, at the same time, treated as one of the subduction zones, and as a unit that bears the characteristics of the shallow subduction process on a broader scale. three elements are distinguished in reconstruction: action footwall (a), reaction hanging wall (r) and the more narrow zone of subduction (s). they coincide with both the palaeogeographical and palaeostructural units. the action wall corresponds to the uplifted anticlinal or monoclinal structure that is being subducted, and the reaction wall is the uplifted anticlinal structure under which the subduction takes place. between these two zones, a markedly unstable, primarily synclinal or synclinorial structure with a consequent relief is named the more narrow zone of subduction. a basic characteristic of the subduction process is the opposing vertical rotation of the two marginal parts the subsidence of the action wall and the reaction wall uplift. the more narrow zone of subduction that lies between is characterised by a continuation of the same tendency. the kinematic process results in formation of the structures of various types and of different intensity of deformation. in this way, the shape as well as both the vertical and horizontal extent of structural deformation in the area of tectonic contact between the action footwall (a) and the more narrow zone of subduction (s), depend on the fault plane geometry (its angle and direction of dip). on the other side, the area of contact between the reaction hanging wall (r) and the more narrow zone of subduction (s), that in this specific case has complex palaeostructural relations, is dominated by helicoidal fault systems of the reverse and even of overthrust character, arranged “en echelon” or merged. the variations in intensity of structural deformations along the both contacts are not gradual. the changes take place on intersections with the transverse and diagonal faults that have markedly horizontal displacement. in the marginal zones involved in the subduction process, these faults are mostly autonomous, but their activity in most cases ceases in the more narrow zone of subduction. traces of the transverse and diagonal faults are often conditioned by the noses of the “en echelon” anticlinal structures. fig. 24 distribution of the quaternary rockfall breccias: a) along the south-western margin of vinodol; b) along the north-eastern margin of vinodol. legend as in fig. 3. sl. 24 poloæaj kvartarnih siparnih breëa: a) uz jugozapadni rub vinodola; b) uz sjeveroistoëni rub vinodola. legenda: vidi sl. 3. 177blaπkoviê: tectonics of part of the vinodol valley within the model of the continental crust subduction the geodynamic processes have been subdivided in the three time-defined phases: 1) the gentle folded structures and a consequent relief were formed in the laramian movements, 2) the eocene pyrrenean movements together with subsequent ones caused formation of the tangential folded and faulted structures, and 3) they obtain a final shape by tectonic reactivation, especially in the quaternary. acknowledgements i would like to gratefully acknowledge the support and critical remarks that were given by dr. ivo veli∆ as well as the review and useful advice from the sides of prof. dr. giovanni battista carulli. assist. prof. dr. bruno safti∆ helped me remarkably in preparation and corrections of english text. figures were drawn by a young colleague jasmina obho–a© and her effort is much appreciated. i would also like to express my thanks to my neighbour in antovo (vinodol), mr. miho jer»inovi∆ who accompanied me during the fieldwork. 7. references aljinovi∆, b. & bla©kovi∆, i. (1981): o plohi dubokih seizmiëkih horizonata sjeveroistoënog jadrana (about the deep seismic horizont in the ne offshore adriatic area).zbornik radova simp. “kompleksna naftno-geoloπka problematika podmorja i priobalnih dijelova jadranskog mora”, split (1981), 1, 363-380, zagreb. fig. 25 schematic and simplified succession of the structural development and changes in position of the rockfall breccias. not to scale. crosssection oriented sw-ne. legend: 1) limestones; 2) flysch; 3) rockfall breccia; 4) relief. sl. 25 shematski i karikirani slijed razvoja struktura i promjena poloæaja slojeva siparnih breëa. nije u mjerilu. orijentacija profila sw-ne. legenda: 1) vapnenci; 2) fliπ; 3) siparna breëa; 4) reljef. 178 geologia croatica 52/2 bahun, s. (1963): geoloπki odnosi okolice donjeg pazariπta u lici (trijas i tercijarne jelar-naslage) (geological relations of the surroundings of donje pazariπte in lika (croatia)).geol. vjesnik, 16, 161170. bahun, s. (1974): tektogeneza velebita i postanak jelar-naslaga (the tectogenesis of mt. velebit and the formation of jelar-deposits).geol. vjesnik, 27, 35-51. bla©kovi∆, i. (1983): o rasprostranjenosti i poloæaju pliocenskih i kvartarnih taloæina u vinodolu (about distribution and position of pliocene and quaternary sediments at vinodol).geol. vjesnik, 36, 27-35. fig. 26 a) photo-sketch of part of the vinodol valley study area (drawn by acad. painter s. matiê). b) traces of the major longitudinal faults of vinodol (14). sl. 26 a) fotoskica dijela istraæivanog podruëja vinodola (izradio akad. slikar s. matiê); b) smjeπtaj osnovnih longitudinalnih rasjeda vinodola (1-4). 179blaπkoviê: tectonics of part of the vinodol valley within the model of the continental crust subduction bla©kovi∆, i. (1991): raspored uzduænih, reversnih i normalnih rasjeda i konstrukcija oblika i dubina ploha podvlaëenja (disposition of the longitudinal, reverse and normal faults and the construction of the forms and depths of the underthrusting surfaces).geol. vjesnik, 44, 247-256. bla©kovi∆, i. (1997): the helicoidal fault systems of vinodol and their genesis.geol. croatica, 50/1, 49-56. bla©kovi∆, i. & aljinovi∆, b. (1981): mikrotektonski elementi kao osnova za model tektonske grae πireg podruëja kvarnera (microtectonic elements as a basis for tectonic model of the broader kvarner area).zbornik radova simpozija “kompleksna naftnogeoloπka problematika podmorja i priobalnih dijelova jadranskog mora”, split (1981), 1, 87-100, zagreb. bla©kovi∆, i. & ti©ljar, j. (1983): prominske i jelar naslage u vinodolu (hrvatsko primorje) (promina and jelar deposits in the vinodol area).geol. vjesnik, 36, 37-50. »ubrilovi∆, v. (1938): geoloπki sastav vinodola i okoline (geologischer bau des vinodol und umgebung).vesn. geol. istr. kralj. jug., vii, 115-33, beograd. dragi»evi∆, i., bla©kovi∆, i., ti©ljar, j. & beni∆, j. (1992): stratigraphy of paleogene strata within the mesihovina-rakitno area (western herzegovina).geol. croatica, 45, 25-52. grimani, i., ©u©njar, m., bukovac, j., milan, a., nikler, l., crnolatac, i., ©iki∆, d. & bla©kovi∆, i. (1973): osnovna geoloπka karta sfrj, 1:100.000, tumaë za list crikvenica l33-102 (geology of the crikvenica sheet 1:100.000).institut za geoloπka istraæivanja, zagreb (1963), savezni geoloπki zavod, beograd, 47 p. herak, m. (1980): sustav navlaka izmeu vrbovskog i delnica u gorskom kotaru hrvatska (the nappesystem between vrbovsko and delnice in gorski kotar croatia).acta geol., 10/2, 35-51, zagreb. kadi∆, o. (1913): bericht über die im jahre 1911 im kroatischen karst ausgeführten kartierungen.jahresbericht ungar.-geol. r.a. (1911), 87-92, budapest. kadi∆, o. kormos, i. & vogl, v. (1912): die geologische verhältnisse des ungarisch-kroatischen küstenlandes zwischen fiume and novi.jahresbericht ungar. geol. ra, (1910), 78-83, budapest. koch, f. (1922): pliocenske paludinske naslage vinodola u hrvatskom primorju (die pliozänen paludinen-schichten im vinodol im kroat. küstengebiete).glasn. hrv. prir. druπtva, 34, 2, 187-193, zagreb. koch, f. (1924): geotektonische beobachtungen im alpino-dinarischen grenzgebiete.zbornik radova posv. j. cvijiêu, 341-358, beograd. kormos, t. (1914): die der küste zugewendete lehne der grossen kapella zwischen novi und stalak.jahresbericht. ungar. geol. ges., (1913), 69-79, budapest. matou©ek, o. (1927): problems of thrust-folding on the northern islands in the adriatic sea.compterendu, 14, congr. géol. intern. (1926), 3-5, madrid. salopek, m. (1960): prilog poznavanju geoloπke grae vinodola (beiträge zur kenntnis des geologischen baues von vinodol (im kroatisehen küstenland)).acta geol., ii, 139-161, zagreb. stache, g. (1889): die liburnische stufe und deren grenzhorizonte.abhandl. geol. reichsanst., 13, 1170, wien. ©u©njar, m., bukovac, j., nikler, l., crnolatac, i., milan, a., ©iki∆, d., grimani, i., vuli∆, æ. & bla©kovi∆, i. (1970): osnovna geoloπka karta sfrj 1:100.000. list crikvenica, l33-102 (basic geological map sfrj, crikvenica sheet).inst. geol. istraæ. zagreb (1961-1969), savez. geol. zavod, beograd. vogl, v. (1912): die fauna eozänen mergel im vinodol in croatien.jahrb ungar. geol. r.a., 20/2, 81114, wien. manuscript received november 10, 1997. revised manuscript accepted november 12, 1999. 180 geologia croatica 52/2 1. uvod morfoloπki vrlo upeëatljiva vinodolska dolina privlaëi paænju geologa kroz viπe od 100 godina. stratigrafski i tektonski obraena, u tektonskom smislu razliëito je tretirana, osobito u pojedinim detaljima. i sada joπ pruæa nove podatke o geoloπkom sastavu i grai koji dopuπtaju daljnje interpretacije (sl. 1). veê u radovima starijih geologa (stache, 1889; kadi∆, 1913; kormos, 1914 i dr.) istaknuta je osnova geoloπkog sastava i grae. sinklinalno poloæene mlae paleogenske fliπne naslage stijeπnjene su vapnenaëkim stijenama starijeg paleogena i gornje krede u usku dolinu pruæanja sjeverozapad-jugoistok. kontakti izmeu fliπnih i vapnenaëkih stijena su najveêim dijelom rasjedni, s izraæenim reverznim karakterom rasjedanja uz dio sjeveroistoënog oboda, osobito u jugoistoënom dijelu doline. vapnenaëke stijene izmeu vinodola i mora formiraju asimetriënu antiklinalu sa strmijim sjeveroistoënim krilom. u jezgri antiklinale su cenomanske vapnenaëko-dolomitne naslage, a na krilima, u kontaktu s fliπom, foraminiferski vapnenci starijeg i dijelom srednjeg paleogena (sl. 2 i 3). sjeveroistoëne padine vinodola, takoer izgraene od gornjokrednih vapnenaca i dolomita te paleogenskih foraminiferskih vapnenaca, kompleksnije su tektonske grae. u sjeverozapadnom dijelu vinodola, izmeu kriæiπêa i triblja, predstavljene su strmije ili blaæe poloæenim jugozapadnim krilom kredno-paleogenske antiklinale. jugoistoëno od triblja, preko griæana i dalje prema novom, strme do okomite vrleti sjeveroistoëne padine rezultat su razorenog tjemena prema jugozapadu prebaëene krednopaleogenske antiklinale. ona je u reversnom rasjednom kontaktu s paleogenskim fliπom vinodola. vapnenaëke naslage sjeveroistoënih padina nastavljaju se prema sjeveroistoku u mezozojski kompleks gorskog kotara. na prvi pogled jednostavnu sinklinalno-antiklinalnu strukturnu shemu vinodola kompliciraju mnoge pojave, do sada nejednoznaëno objaπnjene. to su u prvom redu normalni i reverzni rasjedi dinarskog pruæanja, najoëitiji uz kontakte vapnenaëkih stijena i fliπnih naslaga. zbog njih je vinodol u dijelu literature tretiran kao tektonska graba (koch, 1924; salopek, 1960). kompleksnosti struktura pridonose i manje pojave unutar same vinodolske doline. morfoloπki istaknuto brdo drivenik, izgraeno od gornjokrednih vapnenaca, izbija iz fliπnih paleogenskih naslaga usred doline. sâm postanak drivenika tretiran je u tektonskom smislu razliëito: od strukture horsta do fragmenta navlake (koch, 1924; matou©ek, 1927; salopek, 1960). nadalje, pojava antiklinalno svijenih paleogenskih foraminiferskih vapnenaca istoëno od triblja (humac, kota 101), koja izbija iz fliπnih paleogenskih naslaga, a podsjeêa na drivenik, nije posebno objaπnjavana (salopek, 1960). poloæaj fliπnih naslaga u neposrednoj okolici drivenika, te jugoistoënije u predjelu kostelj-kamenjak, a u vezi s izbijanjem na povrπinu foraminiferskih vapnenaca u predjelu kamenjaka i istoëno od gradine badanj, povod je za pretpostavku o sekundarnim izoklinalnim borama unutar fliπnih naslaga (»ubrilovi∆, 1938). o sekundarno boranom fliπnom kompleksu vinodola svjedoëe i podaci o poloæaju slojeva dobiveni buπenjem u predjelu suπik-tribalj. i drugi podaci o sastavu i grai vinodola, πireg znaëaja ili u pojedinim detaljima, od prije poznati kao i novi, proπiruju saznanja i poveêavaju interes za daljnjim istraæivanjima u cilju odgovora na nerijeπena pitanja, upuêujuêi na odreena objaπnjenja naëina i vremenskog slijeda formiranja struktura i paleogeografskih odnosa. evo ukratko tih podataka. paleocenski vapnenci, s osobitostima kozinskih naslaga, utvreni su u maloj debljini na niz lokaliteta iskljuëivo na sjeveroistoënoj strani vinodola (kadi∆ et al., 1912; »ubrilovi∆, 1938). ©irina pojasa paleogenskih fliπnih naslaga vinodola skokovito se mijenja; izmeu kriæiπêa i drivenika iznosi 350750 m, poveêava se u podruëju drivenika i osobito izmeu drivenika i triblja do pribliæno 1500 m. jugoistoëno od linije sopalj-janjevalj-baπunje naglo je poveêanje na 22502500 m. unutar paleogenskih klastiënih sedimenata vinodola moguêe je izdvojiti dvije razine; starija, rasprostranjena u cijeloj dolini, tipiëni je kompleks fliπnih naslaga srednjeg do gornjeg eocena (grimani et al., 1973). mlaa je predstavljena krupnozrnastijim klastitima, konglomeratiëno-pjeπëanolaporovitim sedimentima i odgovara prominskim naslagama (bla©kovi∆ & ti©ljar, 1983). utvrena je jugoistoëno od drivenika, u dubokim provalijama vitra i pihlja, te na potezu antovo-belgrad-griæane. kao vremenski ekvivalent mlaih klastita, pretpostavljeni su i drugi litotipovi, kao πto su lapori u izmjeni s vapnencima, fosiliferni vapnenci s grebenskom faunom, te dijelom i vapnenaëke breëe jelar-naslaga. nalazi mlaeg nivoa fliπnih pjeπëenjaka, duboko unutar kredno-paleogenskih vapnenaca sjeveroistoënog oboda doline (pihlja i vitra), uz strukturne elemente, jasno govore o znatno kompliciranijim tektonskim odnosima. u prilog kompleksnijih tektonskih odnosa govori i duboko uvlaëenje fliπnih naslaga unutar vapnenaëkih stijena u predjelu diran, istoëno od triblja. gornjopliocenski sedimenti smjeπteni su i saëuvani od erozije uz jugozapadni rub vinodola (koch, 1922; »ubrilovi∆, 1938), u tektonski najintenzivnije poremeêenim predjelima. to, kao i podatak o reverznom rasjednom kontaktu paleogenskih foraminiferskih vapnenaca i paludinskih gornjopliocenskih klastiënih naslaga u predjelu gradine badanj (bla©kovi∆, 1983) govori o vremenu i karakteru rasjedanja. ovom potonjem pridonosi i nalaz pliocenskih naslaga u ponikvi jugozapadno od vrha sopalj, na primorskoj strani grebena izmeu vinodola i mora. daljnji prilog za poznavanje tektonske aktivnosti predstavljaju i podaci o razliëitoj debljini, hipsometrijskoj razini te poloæaju slojeva kvartarnih siparnih breëa sjeveroistoënih i jugozapadnih strana doline. i tektonski elementi upuêuju na kompleksnost struktura. jasno su izraæene suprotne vergencije osnovnih strukturnih jedinica vinodola (kredno-paleogenskih antiklinala sjevetektonika dijela vinodola u svjetlu subdukcije kontinentalne kore ivan bla©kovi∆ 181blaπkoviê: tectonics of part of the vinodol valley within the model of the continental crust subduction roistoënih i jugozapadnih padina), kao i vergencije reverznih rasjeda unutar samog vinodola. navedeni podaci su odredili i predjele detaljnijeg istraæivanja. to je πire podruëje vinodola izmeu kriæiπêa i bribira, odnosno uæi dio doline izmeu drivenika i griæana. prirodno, pri tome su obuhvaêeni i predjeli izmeu vinodola i mora, kao i sjeveroistoëne padine. 2. stratigrafske i strukturne zna»ajke istraæivanog podru»ja sjeveroistoëna strana vinodola izgraena od gornjokredno-paleogenskih karbonata. oni su u kontaktu s fliπnim sedimentima doline. detaljnija analiza poloæaja slojeva, posebno nagiba, karbonatnih stijena ukazuje na kompleksnost tektonske grae (sl. 4). na potezu padine od kriæiπêa do griæana i dalje jugoistoëno, moguêa je podjela na dijelom autonomne strukturne jedinice niæeg reda. granice izmeu njih uglavnom su na dijagonalnim rasjednim zonama (sl. 5). dio padine vinodola, sjeverozapadno od rasjeda ropcidedomir (2), oznaëen je kao strukturna jedinica k r i æ i π ê e p e t r i n o v i ê i . paleogenski i gornjokredni vapnenci nagnuti su prema jugozapadu pod kutem od 45-60°, s tim da veliëina nagiba opada iduêi prema vrhu padine odnosno zaravni sjeveroistoëno. na samom platou, prema podacima o poloæaju slojeva smjeπtena je jezgra kose antiklinale, sa strmijim jugozapadnim krilom. srednji dio sjeveroistoëne padine, izmeu rasjeda ropcidedomir (2) i rasjeda kozak (3), te baπunje-janjevalj, oznaëen je kao strukturna jedinica ropci-maliê. u najveêem dijelu karbonatne padine nagib slojeva prema jugozapadu je izmeu 25-30°, iznimno do 50°. minimalni nagibi slojeva su uz dio kontakta s fliπnim naslagama doline. u uskom pojasu hipsometrijski najviπih litica sjeveroistoënog oboda nagli je prijelaz u obliku koljeniëastog svijanja; maksimalni je nagib slojeva 60-80° pa i 90°. na pripadajuêem platou se na maloj udaljenosti zapaæa promjena poloæaja slojeva; nagnuti su prema sjeveroistoku pod kutem od 20-25°. spomenuto fleksurno svijanje slojeva sve je izrazitije iduêi u smjeru jugoistoka. dokumentirano je i metarskim strukturama (sl. 6a). u nastavku pruæanja prema jugoistoku fleksura prelazi u sinklinalnu strukturu dijelom saëuvanu u podruëju diran, odnosno u istoimeni reverzni rasjed jugozapadne vergencije. kompleks karbonatnih sedimenata jugozapadno od fleksure, na podruëju brda maliê (kota 298), zauzima antiklinalni poloæaj (sl. 7 i 8). treêa strukturna jedinica sjeveroistoëne padine vinodola, b e l g r a d g r i æ a n e , nastavlja se i dalje prema jugoistoku. smjeπtena je istoëno od reverznog rasjeda kozak (3). karakterizirana je prebaëenim slojevima gornjokrednih i paleogenskih vapnenaca koji su nagnuti prema sjeveroistoku pod kutem od 25-30°. s obzirom na inverzan slijed naslaga rekonstruirana je prema jugozapadu prebaëena izoklinalna antiklinala. razoreno tjeme antiklinale tvori vrlo strme do okomite vrleti sjeveroistoëne padine na pruæanju te strukturne jedinice. samo prebacivanje antiklinalne strukture zapaæeno je mnogo sjeverozapadnije. u starom kamenolomu, na platou izmeu razromira i vrha zebar, cenomansko-turonski vapnenci i dolomiti izgrauju prebaëenu antiklinalu dekametarskih dimenzija (sl. 6b). granice izmeu tih strukturnih jedinica su rasjedne, uglavnom s reverznim karakterom rasjedanja. rasjed kriæiπêe-petrinoviêi ( 1 ) je izmeu vapnenaca gornje krede i dijelom paleogena i srednjoeocenskog fliπa. jasno je uoëljiv izrazitom stepenicom u reljefu, uglavnom pravocrtnog pruæanja. rasjedna ploha strmo je nagnuta prema jugozapadu ili pak okomita u dostupnom dijelu promatranja. nagibi slojeva fliπa prema sjeveroistoku te uglavnom prebaëeni slojevi preteæno gornjokrednih vapnenaca na potezu kriæiπêe-veli dol, nagnuti u istom smjeru, nedvojbeno potvruju reverzni karakter rasjedanja. rasjed ropci-dedomir (2) je oznaëen, osim promjenom poloæaja slojeva u strukturnim jedinicama i drugim pokazateljima (sl. 4, 5 i 9). to su znaëajna translacija transgresivne granice izmeu gornjokrednih i paleogenskih vapnenaca, formiranje dviju “provalija” pihlja i vitra s nizom relevantnih podataka, te utvrena gornjokredna antiklinala jugozapadno od vitre. spomenute provalije pihlja i vitra su u foraminiferskim vapnencima sjeveroistoënog oboda vinodola. morfoloπki su jasno oznaëene: pihlja, kao duboko urezana dolina na rasjednoj zoni, i posebno vitra kao provalija poligonalnog tlocrta s dubinom od 20-30 metara. okomito odrezanim stijenama zidovima, zaπtiêena od vjetrova, karakterizirana je izvanredno bujnom vegetacijom, neuobiëajenom za krπko podruëje. preteæno je zastupljena hrastova πuma sa zavidnim dimenzijama jedinki s obzirom na visinu i obujam. u vitri, na okomitim je zidovima dostupna promatranju i sama rasjedna ploha. nagnuta je prema istoku pod kutem od 45°. markirana je promjenom poloæaja slojeva u foraminiferskim vapnencima podinskog i krovinskog krila rasjeda kao i njihovim litoloπkim osobitostima. naime, viπe razine foraminiferskih vapnenaca karakterizirane su znatnim poveêanjem glinovite komponente i prelaze u lapore sa ëestom pojavom roænjaka. upravo pojas takvih laporovitih vapnenaca s roænjacima, kao podinsko krilo rasjeda reverznog karaktera, utvren je na potezu od pihlje preko vitre sve do kontakta s fliπom vinodola jugoistoëno od vitre. na reverzni rasjed upuêuju i drugi podaci prikupljeni u pihlji i vitri. u njima su, na nadmorskoj visini od 320 odnosno 340 metara, utvreni sekundarno krupnozrnasti pjeπëenjaci i lapori, a u vitri i primarni lapori uz pojavu vode, identiëni onima iz mlae razine paleogenskih klastita (bla©kovi∆ & ti©ljar, 1983). ti nalazi su smjeπteni oko 150 metara iznad najviπe toëke fliπkih naslaga pripadajuêeg dijela doline. o karakteru i pruæanju rasjeda, te kompleksnosti strukturnih odnosa sjeveroistoëne padine vinodola, govori i pojava gornjokrednih vapnenaca u uskom pojasu jugozapadno od vitre. utvrena je sekundarna antiklinalna struktura, u pruæanju presjeëena popreënim i dijagonalnim rasjedima. tom pojavom naruπena je slika kontinuiteta foraminiferskih vapnenaca u grai jugozapadnog krila antiklinalne strukture sjeveroistoëne padine vinodola, kao i cjelovitost same strukture. utvreni reverzni rasjed ropci-dedomir, u produæenju pruæanja prema jug-jugoistoku jasno je uoëljiv kao graniëni kontakt izmeu karbonatnih stijena strukturne jedinice ropcimaliê i fliπa vinodola. prema sjever-sjeverozapadu se ne moæe pratiti u monotonom gornjokrednom karbonatnom kompleksu na platou iznad vinodola. na relaciji mahavice-diran odnosno kozak, dva rasjeda istog karaktera stapaju se u predjelu baπunje u jedinstveni reverzni rasjed kozak (3). oni odjeljuju strukturne jedinice ropci-maliê i belgrad-griæane (sl. 5 i 7). u nastavku prema jugoistoku rasjed kozak je znatno izrazitiji i predstavlja granicu izmeu gornjokredno-paleogenskih vapnenaca strukturne jedinice belgrad-griæane i srednjoeocenskog fliπa vinodola. u najveêem dijelu njegova pruæanja, osobito jugoistoëno od dirana, jasno je izraæen reverzni karakter rasjedanja. uglavnom prebaëeni gornjokredni i paleogenski vapnenci navuëeni su na srednjoeocenski fliπ. sjeverozapadno od dirana 182 geologia croatica 52/2 odnosno kozaka do predjela mahavice evidentno je ustrmljivanje rasjedne plohe do okomitog poloæaja, pa i prebacivanje. i jugozapadna granica karbonatne padine vinodola, na potezu kriæiπêe-janjevalj, prema fliπkim naslagama doline je rasjedna s reverznim karakterom kretanja. rasjedni kontakt je na mnogim mjestima pokriven siparnim breëama i nije u svim strukturnim jedinicama jasno definiran. na prvi pogled jedinstven za strukturne jedinice kriæiπêe-petrinoviêi i ropcimaliê, predstavlja stopljen produæetak dijagonalnih graniënih rasjeda kriæiπêe-petrinoviêi i dedomir-ropci (sl. 5). na mjestima gdje je dostupan promatranju, rasjedni kontakt je morfoloπki istaknut u obliku oπtre i visoke stepenice. slojevi fliπnih pjeπëenjaka nagnuti su prema sjeveroistoku, a foraminiferski vapnenci karbonatne padine prema jugozapadu. indikativno je i povijanje slojeva foraminiferskih vapnenaca: pribliæavajuêi se kontaktu slojevi su sve veêeg nagiba (sl. 10). nasuprot tome, na potezu suπik-janjevalj, u direktnom su kontaktu, s gotovo sukladnim poloæajem slojeva, najmlai ëlanovi foraminiferskih vapnenaca i fliπnih lapora. kontakt djeluje kao normalni konkordantni slijed. no, i ovdje se pretpostavlja rasjedni kontakt, iako nije obavljena detaljnija stratigrafska analiza sa ciljem utvrivanja vremenskog kontinuiteta. osnova za tu pretpostavku nalazi se u ëinjenici da je ta granica u πirem prostoru vinodola karakterizirana reverznim rasjedom i drugo, u prilog takovog rasjeda govori i povijanje slojeva foraminiferskih vapnenaca neposredno uz kontakt, kako je i gore opisano. sukladan poloæaj slojeva obaju krila rasjeda moæe biti i posljedica karaktera strukturnih deformacija, o ëemu êe joπ biti rijeëi. nakon opisa graniënih rasjeda strukturnih jedinica, a i pregleda sliënih istiëu se njihove zajedniëke karakteristike (sl. 11), t.j. helikoidalni oblik (bla©kovi∆, 1997). pruæanje rasjeda je sigmoidalnog ocrta. na platou sjeveroistoëno od vinodola je dinarsko s prijelazom u dijagonalno na karbonatnoj padini, te stapanjem dva ili viπe rasjeda u jedinstveni rasjed dinarskog pruæanja na granici karbonatnog kompleksa s fliπom vinodola. istim smjerom odvija se i promjena nagiba paraklaza te moguênost njihova identificiranja: od gotovo vertikalnog poloæaja paraklaze se postupno naginju prema sjeveroistoku sve do 60-50°, odnosno 30-25°. sa smanjenjem nagiba paraklaza raste intenzitet reverznog rasjedanja. popreëni rasjedi, s pruæanjem sjeveroistok-jugozapad, su brojni i uglavnom su to rasjedi s vertikalnom paraklazom i horizontalnim kretanjem krila. od njih se istiëu oni u predjelima pihlja i vitra, te osobito rasjed baπunje-janjevalj, koji dijelom predstavlja i jugoistoënu granicu strukturne jedinice ropci-maliê. sama dolina je izgraena preteæno od fliπnih naslaga eocenske starosti. valja istaknuti i neke detalje kronoi litostratigrafskih kao i tektonskih osobitosti tih sedimenata i drugih stijena u dolini. stariji dio fliπnih sedimenata je predstavljen tipiënom izmjenom pjeπëenjaka i znatno viπe zastupljenih lapora. sadræi bogatu fosilnu faunu velikih foraminifera, dijelom identiënu onoj iz foraminiferskih vapnenaca. no, u neposrednoj blizini drivenika unutar krupnozrnastih pjeπëenjaka i manje lapora, uz pretaloæene alveoline, numulite i asiline, bogata je fauna litoralnog podruëja s brojnim primjercima antozoa, ehinida, brahiopoda, lamelibranhiata i gastropoda (vogl, 1912). mlai dio sedimenata fliπnog tipa diskordantno leæi na starijoj razini (bla©kovi∆ & ti©ljar, 1983). sastoji se od konglomerata, konglomeratiënih i krupnozrnastih biokalkarenita te litiënih arenita. bogati su fosilima. osim brojne pretaloæene makrofaune i foraminifera iz starijeg fliπa sadræe i autohtonu fosilnu faunu gastropoda i lamelibranhiata. na temelju fosilnog sadræaja pretpostavlja se gornjoeocenska starost mlaeg dijela klastita vinodola. tektonski poloæaj starijih fliπnih sedimenata vinodola odreen je rubnim, reverznim rasjedima na dodiru s vapnenaëkim stijenama sjeveroistoëne i jugozapadne padine. u samoj dolini su izmjereni poloæaji slojeva nagnuti prema sjeveroistoku ili jugozapadu, s veliëinom nagiba od 30-60°. oni daju osnovu za rekonstrukciju boranih struktura: antiklinala i sinklinala od uspravnih i kosih, odnosno prebaëenih te normalnih do izoklinalnih. posebnost u morfologiji i geologiji vinodola predstavljaju istaknute i osamljene pojave uzviπenja izgraenih iz gornjokrednih (drivenik) i foraminiferskih vapnenaca (humac kota 101, istoëno od triblja), u dijelom zaravnjenom, fliπnom, reljefu. foraminiferski vapnenci pojavljuju se i kao jezgre antiklinala u predjelima kamenjak i badanj. male povrπine, ali uoëljiv visinom i oblikom, drivenik je jedan od srediπnjih, razliëito objaπnjavanih geoloπkih osobitosti vinodola (sl. 12). izgraen je uglavnom od gornjokrednih rudistnih vapnenaca i okruæen eocenskim fliπnim naslagama. oπtre i strme padine drivenika i tektonske breëe ukazuju na rasjedne kontakte vapnenaca i fliπa. iako je sigurno odreivanje poloæaja slojeva onemoguêeno mnogobrojnim pukotinama i ograniëenim povrπinama promatranja, na jugoistoënim padinama drivenika, podno ograde groblja, nazire se blago antiklinalno svijanje slojeva rudistnih vapnenaca. potkrijepljeno je i identiënim poloæajem sloja tamnije smee boje unutar gotovo bijelih rudistnih vapnenaca. na antiklinalnu strukturu joπ jasnije upuêuju nalazi baznih transgresivnih paleogenskih breëa na jugozapadnoj, i gotovo bijelih alveolinskih vapnenaca uz transgresivne breëe na sjeveroistoënoj padini drivenika. u prilog i paleogeografski izdignutog oblika indirektno govore spomenuti podaci, bogata fosilna zajednica litoralne sredine (vogl, 1912), u vrijeme taloæenja fliπnih naslaga starijeg nivoa, te grebenski vapnenci i numulitne breëe mlaeg nivoa klastiënih naslaga (bla©kovi∆ & ti©ljar, 1983) na jugoistoënim padinama drivenika. morfoloπki istaknuto uzviπenje humac, stoæastog oblika, istoëno od triblja (kota 101), izgraeno je iz foraminiferskih vapnenaca. okruæeno je fliπnim naslagama. poloæaj slojeva vapnenaca omoguêuje rekonstrukciju normalne antiklinale (salopek, 1960). bez elemenata ëela strukture, i s obzirom na dimenzije i fliπno okruæenje, to uzviπenje predstavlja fragment antiklinale dinarskog pruæanja, izdignut uz popreëne rasjede. izdanci foraminiferskih vapnenaca u fliπnom okruæenju utvreni su i u predjelu jugozapadno od naselja kamenjak. tektonski su poremeêeni i nejasnog poloæaja, no u literaturi su tretirani kao jezgra prebaëene izoklinalne antiklinale ( » ubrilovi∆, 1938). formiraju zamjetljivu stepenicu u reljefu. u vododerini potoka malenica uz kamenolom badanj, foraminiferski vapnenci s krovinskim fliπnim sedimentima nagnuti su prema sjeveroistoku kao jezgra prebaëene izoklinalne antiklinale (sl. 13). glinovito-siltozne taloæine pliocenske starosti utvrene su na manjim povrπinama u jugozapadnom dijelu doline, kod lokaliteta katiêi, ceroviêi i badanj (koch, 1922; »ubrilovi∆, 1938; bla©kovi∆, 1983) saëuvane su od troπenja zahvaljujuêi uglavnom tektonski formiranim, zatvorenim udubljenjima, u kojima su smjeπtene. kvartarne sipariπne breëe, osobito one smjeπtene uz rubove doline, uz kontakt fliπa vinodola i vapnenaëkih padina zasluæuju posebno isticanje. povrπinski i debljinom znatnije su zastupljene uz sjeveroistoëni rub vinodola, prateêi intenzitet 183blaπkoviê: tectonics of part of the vinodol valley within the model of the continental crust subduction poremeêaja karbonatne padine. na mjestima veêih izdanaka jasno je izraæena gruba kosa slojevitost. u blizini naselja ropci i petrinoviêi, sipariπne breëe su blago nagnute prema jugozapadu, pod kutom od 15-20°. na znatno veêem pozajmiπtu materijala (franoviê) slojevi sipariπnih breëa su gotovo horizontalni ili vrlo blago nagnuti prema dolini ili ëak sjeveroistoku. uz jugozapadni rub vinodola istovrsne breëe, u znatno manjoj debljini, ustanovljene su kod naselja katiêi i stranëa te ispod gradine badanj. gruba uslojenost, pokazuje nagib prema sjeveroistoku pod kutom od 38-44°. istaknuti greben izmeu vinodola i mora je asimetriënog oblika i strukturne grae. s prosjeënim visinama od 300-350 metara, blago je nagnut prema moru te sa strmim padinama prema vinodolu. izgraen je preteæno iz gornjokrednih vapnenaca i dolomita te paleogenskih foraminiferskih vapnenaca. u strukturnom pogledu predstavlja kosu antiklinalu sjeveroistoëne vergencije, s blago nagnutim jugozapadnim krilom od 25-35° te strmije poloæenim sjeveroistoënim krilom, od 3055°. sjeveroistoëno krilo strukture odnosno padine grebena izgraene su preteæno iz foraminiferskih vapnenaca. oni tvore jugozapadnu stranu odnosno rub vinodola. duæ cijelog ruba markantan je rasjedni kontakt (jugozapadni vinodolski rasjed 4) izmeu preteæno foraminiferskih vapnenaca i fliπa doline (sl. 14), no mjestimiëno s interesantnim detaljima. tako paænju zasluæuju odnosi u usjeku ceste griæanecrikvenica u kanjonskom dijelu potoka malenica, gdje dolazi do sukobljavanja struktura suprotnih vergencija, jugozapadnog ruba doline i same doline (sl. 13). rasjedna ploha kontakta izmeu foraminiferskih vapnenaca jugozapadne padine i fliπa vinodola nagnuta je prema zapad-jugozapadu pod kutom od 50° s okomitim tektonskim prutanjem. foraminiferski vapnenci krovinskog krila rasjeda, leæe na tektonski oπteêenim fliπnim laporima. istoëno-sjeveroistoëno, skoro paralelno ovom rasjedu, na maloj udaljenosti, utvren je reverzni rasjed suprotne vergencije, s promjenljivim elementima poloæaja po pruæanju (od 26°/82° do 35°/10°). tim rasjedom u kontaktu su fliπni sedimenti kao podinsko krilo i na njima mlai, numulitni nivo foraminiferskih vapnenaca, kao vjerojatni izbojak antiklinalnog niza izoklinalne serije unutar fliπnih naslaga vinodola (kamenjak-kostelj), u smislu shvaêanja struktura prema »ubrilovi∆u (1938). ovdje valja istaknuti detalje rasjedne plohe, odnosno promjene veliëine njezinoga nagiba. sukladno smjeru nagiba orijentirana tektonska prutanja, odreuju vertikalno kretanje uz paraklazu. za naknadna razmatranja indikativna je zaobljenost paraklaze: nagnuta prema sjeveroistoku, u hipsometrijski najviπem dijelu najstrmije je poloæena (82°). spuπtajuêi se do razine ceste nagib paraklaze postupno se smanjuje sve do 50°, a lateralno, i na maloj udaljenosti (cca 100 m) po pruæanju prema sjever-sjeverozapadu, i do 10°. prateêi dalje jugozapadni rub vinodola, u zasjeku ceste tribalj-crikvenica, podno gradine badanj, jasno je vidljiv reverzni rasjedni kontakt, uz koji foraminiferski vapnenci leæe na glinovito-siltoznim naslagama mlaeg pliocena. rasjedna ploha je nagnuta prema sjever-sjeveroistoku pod kutom od 53° (bla©kovi∆, 1983). u πirem predjelu uzviπenja sopalj (kota 327), jugozapadno od triblja, zabiljeæeni su daljnji indikativni podaci. sopalj je istaknuto uzviπenje sa strmim liticama prema dolini (sl. 15). djeluje kao da je izbaëen prema sjeveroistoku, u dolinu, iz cjeline vapnenaëkog grebena izmeu vinodola i mora. u zaleu uzviπenja, prema moru, formirana je zaravan trokutaste povrπine, otvorena prema jugozapadu, i s pojavom vode u jednoj od “ponikva”. i geoloπki podaci sukladni su geomorfoloπkim osobitostima. znatni pomaci transgresivne granice izmeu gornjokrednih i paleogenskih vapnenaca nesumnjivo ukazuju na popreëne rasjede. njima je i obrubljena spomenuta trokutasta zaravan. oznaëeni su i πirokim zonama milonitiziranih i breëastih vapnenaca. na sjeciπtu tih rasjednih zona, u udubljenju s vodom, utvreni su glinovito-siltozni, dijelom limonitizirani sedimenti. mikropaleontoloπkom analizom uzoraka, za koju zahvaljujem dr ani soka», utvreno je da te tvorevine nose obiljeæja slatkovodnih taloga i vjerojatno pripadaju mlaem neogenu ili starijem kvartaru. od fosilnih ostataka odreeni su c a n d o n a cf. n e g l e c t a sars, t y p h l o c y p r i s sp., i i l y o c y p r i s sp. sedimentoloπko-petrografskom analizom, izraenom ljubaznoπêu dr josipa ti©ljara, uzorak tih stijena je odreen kao kalcitom bogati lapor, izgraen od kriptokristalastog kalcita i gusto, pahuljasto grupirane smjese minerala glina. samo sporadiëno sadræi vrlo sitna zrnca kvarca i rijetke pojedinaëne listiêe sericita. s obzirom na sastav i strukturu uzorak ove stijene je vrlo sliëan gornjopliocenskim glinovito-siltoznim sedimentima na spomenutim lokalitetima u vinodolu. i navedeni rezultati analize mikropaleontoloπkog sadræaja ne osporavaju takav zakljuëak. spomenuti popreëni rasjedi, u svom produæenju prema sjeveroistoku, obrubljuju sa sjeverozapadne i jugozapadne strane uzviπenje sopalj i nastavljaju se u dolini prema triblju odnosno zaseoku janjevalj. i ovdje dovode do promjena opêe slike geoloπkog sastava i grae jugozapadnog ruba doline. izmeu njih, a podno soplja (zaseok katiêi), smjeπteni su gornjopliocenski sedimenti u najveêoj debljini (koch, 1922). diskordantno poloæeni na fliπne naslage, saëuvani su u uvjetima sukobljavanja sinklinalnog poloæaja fliπa (slojevi nagnuti prema jugozapadu) i gotovo okomitog poloæaja paraklaze jugozapadnog vinodolskog rasjeda (4). okruæenje gornjopliocenskih naslaga, iako velikim dijelom pokrivenih siparima, kao i morfologija terena, upuêuju na rasjedne kontakte. foraminiferski vapnenci zapadno od pilina predstavjaju daljnju posebnost ovog dijela vinodola. morfoloπki uoëljivi, u obliku asimetriëno izdignutog reljefa, trokutaste povrπine, duboko se uvlaëe u fliπne naslage doline. oslonjeni su na strme sjeveroistoëne padine grebena haldin, ali sa zamjetljivo blaæim reljefom. na sjeverozapadnoj i jugozapadnoj strani rasjedima su ograniëeni: uz rasjed sopalj-janjevalj od pliocenskih naslaga, te od foraminiferskih vapnenaca grebena haldin jugozapadnim vinodolskim rasjedom (4). istoëna granica foraminiferskih vapnenaca pilina oznaëena je konkordantnim prijelazom u fliπne naslage vinodola. donekle sliënu situaciju “izbacivanja” dijela vapnenaëkog grebena izmeu vinodola i mora prema dolini, uz popreëne rasjede i uz popratno kompleksnije strukturne odnose u fliπnom dijelu doline (drivenik), susreêemo u predjelu graëiπêe (kota 289) (sl. 12). kao posljedica toga su u direktnom rasjednom kontaktu uz eocenske foraminiferske vapnence i gornjokredni rudistni vapnenci s eocenskim fliπnim naslagama. jugozapadni vinodolski rasjed (4) je jedna od struktura s morfoloπki naglaπenom stepenicom u reljefu, te geoloπki, kontaktom kontrastnih fliπnih naslaga i foraminiferskih vapnenaca. sâm rasjedni kontakt, kao i rasjedna ploha pokriveni su aktivnim siparima i rijetko dostupni snimanju. meutim, i u takvim uvjetima utvren je poloæaj paraklaze na niz mjesta. ona je uglavnom nagnuta prema sjeveroistoku s nagibom od 50-85°, a na dva lokaliteta (badanj, sopalj) utvren je i nagib paraklaze prema jugozapadu pod kutem od 50 odnosno 72°. do promjena u veliëini i smjeru nagiba paraklaze dolazi najëeπêe uz brojne popreëne i dijagonalne rasjede, kojima je naruπen kontinuitet u pruæanju jugozapadnog vinodolskog rasjeda. 184 geologia croatica 52/2 svi navedeni detalji geoloπkog sastava i grae pojedinih predjela u podruëju vinodola predstavljaju poticaj i osnovu za rekonstrukciju naëina postanka struktura, rasprostranjenosti pojedinih kronostratigrafskih jedinica i vremenskog slijeda zbivanja. u nastavku je izloæen pokuπaj takve rekonstrukcije. osniva se na mobilistiëkom pristupu, u kojem se vinodol smatra jednom od zona plitke subdukcije kontinentalne kore (a-tip subdukcije), odnosno podvlaëenja (herak, 1980; bla©kovi∆ & aljinovi∆, 1981; bla©kovi∆, 1991). 3. model podvla»enja kao osnova za postanak i interpretaciju struktura 3.1. temeljne postavke modela model podvlaëenja (sl. 16) je temeljen na analizi mikrotektonskih elemenata iz podruëja ∆iêarije (bla©kovi∆ & aljinovi∆, 1981), te geoloπkih odnosa πireg podruëja uz rezultate dobivene metodama seizmiëkog istraæivanja (aljinovi∆ & bla©kovi∆, 1981). njime se pretpostavlja kretanje i podvlaëenje ploëe prema sjeveroistoku (recentna orijentacija) sa πirom zonom horizontalne i uæom zonom vertikalne komponente kretanja (samim podvlaëenjem odnosno subdukcijom). u prvoj fazi (kolizijskog procesa) dolazi do boranja sedimentnog kompleksa. time su odreeni predjeli sinklinalnih odnosno antiklinalnih struktura (bla©kovi∆ & aljinovi∆, 1981). strukture su u toj fazi konsekventne morfologiji. time istovremeno mogu biti predodreeni prostori razliëitih sedimentacijskih reæima. u nastavku kretanja uz deformaciju primarnih struktura u smislu sve veêe asimetrije bora s preteæno jugozapadnom vergencijom, formiraju se dislokacije reverznog karaktera i zapoëinje proces podvlaëenja prvenstveno u labilnim, za spuπtanje predisponiranim sinklinalnim strukturama (sl. 17). aktivni dio kontinentalne kore u horizontalnom kretanju i subdukciji definiran je kao podinsko krilo akcije a i karakteriziran je odreenim strukturnim i facijesnim osobitostima. to su preteæno plikativne deformacije i dominacija plitkomorskih uglavnom konkordantnih sedimenata, eventualno s kratkotrajnim emerzijama ili ëeπêe opliêavanjima osobito izraæenim u predjelima antiformnih struktura. normalno je oëekivati i pravilan, zonaran raspored litofacijesa. relativno pasivni dio kontinentalne kore, definiran je kao krovinsko krilo otpora ili reakcije r . u poëetnoj fazi odgovara stabilnijoj, antiformnoj strukturi, koja tijekom nekontinuiranog procesa podvlaëenja preuzima ulogu pruæanja otpora. pri tome je izloæena znatnim strukturnim deformacijama plikativnih i osobito disjunktivnih karakteristika s opêom tendencijom izdizanja. u sedimentacijskom procesu to rezultira ëeπêim emerzijama, nepravilnim rasporedom, prostornim ograniëenjem i malom debljinom raznovrsnijih litofacijesa te znatnijim udjelom klastiënih i gruboklastiënih sedimenata. pod pojmom uæa zona subdukcije s podrazumijeva se relativno uski pojas dodira dviju ploëa (a i r) i njihovog antagonistiëkog vertikalnog kretanja. taj pojas aktivnog podvlaëenja odgovara primarnoj labilnoj sinformnoj strukturi (sinklinala, sinklinorij). strukturne deformacije u toj zoni koje nastaju u periodima intenzivnijeg podvlaëenja, imaju plikativne i rasjedne osobitosti saæimanja. to je popraêeno znatnim horizontalnim i vertikalnim raznolikostima litofacijesa. izraæena je dominacija klastiënih sedimenata fliπnih ali i molasnih karakteristika. u kontinuitetu sedimentacije postoji i moguênost promjena taloæne sredine (marinska-slatkovodna ili obratno) kao i formiranje kutnih disordancija uslijed sinsedimentacijskih pokreta podvlaëenja. 3.2. primjena i razrada modela za istraæivano podru»je vinodola podruëje vinodola, kao jedna od markantnijih zona plitke subdukcije, sadræi “u malom” veêinu karakteritika podvlaëenja (plitke subdukcije) na πirem prostoru. karakteristike takvog podvlaëenja, s tek generalnim napomenama o sedimentaciji i strukturnim promjenama, dijelom u pojedinim vremenskim fazama subdukcijskog procesa, a s osloncem uglavnom na geologiju istraæivanog podruëja, predoëene su na slici 17. pri tome je izvrπena i tektonska razdioba vinodola. tako je karbonatni greben izmeu vinodola i mora definiran kao rubni dio podinskog krila akcije a, sjeveroistoëne karbonatne padine vinodola kao dio krovinskog krila otpora ili reakcije r, a sama uglavnom fliπna dolina kao uæa zona subdukcije s. slijedi i kratki komentar priloga. inicijalna kolizijska kretanja smjeπtena su u okviru laramijskih pokreta krajem krede. njima su formirane blage bore i ostvareni uvjeti za emerziju odnosno taloæenje kozinskih vapnenaca ili njihovih facijesnih ekvivalenata u najdubljim dijelovima paleoreljefa sinklinalnim strukturama (faza i). iz razmatranja je izostavljen period relativno stabilne sedimentacije foraminiferskih vapnenaca, iako je veê u donjem eocenu moglo doêi do inicijalnih subdukcijskih kretanja, u smislu intenzivnijeg tonjenja labilnih sinklinalnih dijelova s diferencijacijom sedimentacijskih reæima, t.j. istovremenog taloæenja foraminiferskih vapnenaca i fliπnih naslaga (dragi»evi∆ et al., 1992). shemom je obuhvaêen interval intenzivnog taloæenja klastiënih sedimenata (faza ii). u tom vremenu, prvotno zatomljen ili slabije izraæen, nastavlja se proces subdukcije. u uæoj zoni subdukcije (s), primarnoj sinklinali izmeu dva antagonistiëka krila (a i r), intenziviranjem podvlaëenja dolazi do rotacije suprotne smjeru kazaljke na satu oko horizontalne osi; antiklinala ili monoklina, kao rubni dio podinskog krila akcije (a), tone i podvlaëi se, a antiklinalna struktura nasuprot, kao rubni dio krovinskog krila otpora (r), u postupnom je izdizanju. rezultat takvog suprotnog kretanja je i premjeπtanje osi sinklinale odnosno uæe zone subdukcije u smjeru suprotnom osnovnom kretanju, πto se odraæava u asimetriënom rasporedu kozinskih naslaga. nastavak i intenziviranje subdukcijskog procesa odraæava se u taloæenju preteæno klastiënih sedimenata, u poëetku sitnozrnastih a kasnije, i s moguênoπêu diskordancije, krupnozrnastih stijena. njihova sedimentacija vezana je uz znatnije strukturne deformacije i u πirem podruëju. promjene u okoliπu rezultiraju raznolikim litofacijesima (fliπ, prominska formacija, jelar formacija). u zadnjoj, iii fazi, povezanoj s prethodnom, koja se vremenski prema podacima s istraæivanog podruëja, moæe eventualno vezati i uz postanak jelar-naslaga te kasnije i kvartarnih sipariπnih breëa, a prisutna je i danas, pretpostavlja se nekontinuirano ali intenzivno podvlaëenje. finalni rezultat procesa subdukcije je odraæen u znatnoj redukciji πirine uæe zone podvlaëenja (s), te intenzivnim strukturnim deformacijama stijena u toj i susjednim zonama (a i r). primjeri iz istraæivanog podruëja pokazuju da deformacije nisu identiëne po karakteru i intenzitetu u svim zonama. u prvom redu ovise o zateëenim strukturama, fiziëkim osobitostima stijena te naëinu kretanja krila. kompleks podinskog krila akcije (a) u intervalu horizontalnog kretanja, uz uglavnom zadræavanje pribliæno istog hipsometrijskog nivoa, podloæan je preteæno plikativnim deformacijama sa sukladnom do eventualno suprotnom vergencijom bora odnosno reverznih rasjeda smjeru kretanja. u kontaktu sa zonom subdukcije (s), odnosno u intervalu promjene 185blaπkoviê: tectonics of part of the vinodol valley within the model of the continental crust subduction kretanja u smislu podvlaëenja, formira se antiklinalna, kao u sluëaju grebena izmeu vinodola i mora, ili eventualno monoklinalna struktura (sl. 17, alternativa iiia). podvlaëi se cijeli kompleks krila akcije. uæa zona subdukcije (s), prvotno sinklinala ili sinklinorij, s kompleksom klastiënih stijena znatne debljine, izloæena je djelovanju suprotnih sila: horizontalno-vertikalnoj komponenti podvlaëenja (a) s jedne i horizontalno-vertikalnoj (u smislu izdizanja) komponenti krila otpora (r) s druge strane. dio sedimentnog kompleksa zone subducira se zajedno sa stijenama krila akcije, a preteæno viπi dio kompleksa, usljed pribliæavanja krila akcije i otpora, t.j. redukcije πirine, istiskuje se uz istovremeno formiranje raznolikih sekundarnih tangencijalnih struktura, reversnih rasjeda, izoklinalnih, prebaëenih i kosih bora. vergencija struktura je uglavnom suprotna smjeru osnovnog kretanja. istiskivanje dijela kompleksa je asimetriëno: osobito je izraæeno uz kontakt sa stijenama krovinskog krila otpora (r) kao posljedica karakteristika kretanja tog krila. zona krovinskog krila otpora (r) pruæa otpor horizontalnoj komponenti osnovnog kretanja. zbog toga kao i samog podvlaëenja predstavlja podruëje izdizanja uz intenzivne tangencijalne plikativne i osobito disjunktivne deformacije, koncentrirane uz kontakt s prethodnom zonom. od struktura dominiraju prebaëene do izoklinalne bore te reversni rasjedi uz moguênost “navlaëenja”. vergencija struktura je u pravilu suprotna smjeru osnovnog kretanja, a iznimno, i to dublje u zoni reakcije, i sukladna. granice izmeu pojedinih zona (a-s-r), u ovom sluëaju antiklinalnih nasuprot sinklinalnim strukturama, u pravilu su rasjedne. zajedniëka im je karakteristika oblik rasjedne plohe, u vertikalnom presjeku viπe ili manje izduljenoj zrcalnoj slici slova s (bla©kovi∆ & aljinovi∆, 1981), i u krajnjoj konsekvenciji, s obzirom na kompresiju, reverzni karakter kretanja. 4. interpretacija geneze struktura istraæivanog dijela vinodola na temelju iznesenih postavki modela uraena je interpretacija u uvodnom dijelu (odjeljak 2) navedenih detalja o sastavu i grai ovog dijela vinodola. asimetriëki vapnenaëki greben izmeu vinodola i mora shvaêen je kao rubni dio podinskog krila akcije (a) u zoni prijelaza iz horizontalne u vertikalnu komponentu kretanja, t.j. samo podvlaëenje. posljedica je izraæena morfoloπki, s obzirom na asimetriju grebena, a i strukturno, kosom antiklinalom sa sjeveroistoënom vergencijom. potvrdu takvog kretanja nalazimo u spomenutom “izbacivanju” dijela grebena prema vinodolu uz dijagonalne rasjede (kota 327, sopalj). modelirani pokuπaj simuliranja procesa izbacivanja (sl. 18) jasno ukazuje na karakter kretanja i daje objaπnjenje rasporeda i poloæaja dominantnih zjapeêih pukotina na grebenu kao i promjene nagiba paraklaze jugozapadnog vinodolskog rasjeda (4), na kontaktu s gornjopliocenskim klastiënim naslagama same doline. u ovom rubnom dijelu podinskog krila akcije (a) rotacijsko kretanje u podvlaëenju, uz odreene strukturne elemente, dovodi do relativnog izdizanja grebena, i spuπtanja dodirnog dijela klastiënih sedimenata uæe zone subdukcije (s), t.j. doline. o tome svjedoëe nalazi gornjopliocenskih sedimenata u zaleu brda sopalj na nadmorskoj visini od 225 m u odnosu na istovremene klastiëne naslage u dolini podno istog vapnenaëkog grebena na visini od 100-155 metara. geoloπka situacija i rekonstrukcija primarnih uvjeta prikazani su na slici 19. jugozapadni rub vinodola je poistovjeêen sa zonom kontakta podinskog krila akcije (a) i uæe zone subdukcije (s). na terenu je predstavljen jugozapadnim vinodolskim rasjedom. uz taj rasjed vezane su najznaëajnije strukturne promjene. promjene nagiba helikoidalne rasjedne plohe jugozapadnog vinodolskog rasjeda (4), kreêu se u rasponu od 48° s nagibom prema sjeveroistoku, preko okomitog do prebaëenog poloæaja s nagibom prema jugozapadu pod 50°. do promjena poloæaja paraklaze najëeπêe i naglo dolazi uz popreëne i dijagonalne rasjede. ovisno o veliëini nagiba razliëite su strukturne deformacije u stijenama doline odnosno uæe zone subdukcije (s) (sl. 20, sl. 14). uz blaæi nagib rasjedne plohe, nagnute prema sjeveroistoku, dolazi do relativnog izdizanja krovinskog krila rasjeda, pojave starijih stijena na povrπini, kakav je i izolirani sluëaj zapadno od pilina uz izostajanje deformacija veêih razmjera unutar fliπnih naslaga u produæetku profila prema sjeveroistoku. uz veêi nagib rasjedne plohe, izmeu 65-80°, i koji je karakteristiëan za preteæni dio jugozapadnog ruba vinodola, u kontaktu su paleogenski vapnenci i fliπne naslage. pretpostavlja se znatniji horizontalni domet plikativnih deformacija unutar fliπnih sedimenata doline. okomiti, odnosno okomitom bliski poloæaj rasjedne plohe, kao πto je sluëaj u podruëju naselja podsopalj dovodi do antiklinalnog oblikovanja a istovremeno i relativnog izdizanja kompleksa stijena krovinskog krila rasjeda ili krila u smjeru pritiska. to izaziva i znatnije strukturne promjene u smislu boranja s veêim horizontalnim domaπajem, kako je buπenjima utvreno u predjelu podsopalj-suπik. prebaëeni poloæaj paraklaze joπ uvijek vrlo strmog nagiba, kao u podnoæju vrha sopalj (sl. 19) uz ograniëenja popreënim rasjedima, uvjetuje uz sinklinalno svijanje i pojaëano tonjenje fliπnih i mlaih (pliocenskih) naslaga u krilu rasjeda s mlaim naslagama i moguênost njihovog oëuvanja od naknadne erozije. kompenzaciju dubljem spuπtanju uz jugozapadni rasjed nalazimo u sekundarnom boranju fliπnih naslaga πireg prostora u smjeru profilne linije, i dijelom u izdizanju i antiklinalnom oblikovanju foraminiferskih vapnenaca (humac, kota 104). blaæem nagibu prebaëene rasjedne plohe, kao πto je dijelom pretpostavljeno u podruëju profila graëiπêe-drivenik (sl. 12), i utvreno u predjelu kamenoloma badanj (sl. 14), odgovaraju znaëajnije strukturne promjene na manjem prostoru a veêeg vertikalnog domaπaja. one nalaze izraz u tektonskom prodoru stijena podloge fliπnog kompleksa, paleogenskih foraminiferskih vapnenaca (kamenolom badanj), ili ëak starijih, gornjokrednih vapnenaca. nastale su kao posljedica dubljeg domaπaja pritisaka podvlaëenja, prenoπenih poloæajem i nagibom rasjedne plohe, kao i zateëenim izdignutim ili utonulim paleostrukturnim oblicima u vrijeme konaënog oblikovanja, kao u sluëaju drivenika. pribliæavanje struktura veêeg intenziteta deformacija uslijed sve blaæeg nagiba prebaëene rasjedne plohe, kako se vidi kod kamenoloma badanj (sl. 14), u odnosu na sluëaj kod drivenika (sl. 12), moæe iêi sve do uklijeπtenja sinklinalno oblikovanih fliπnih naslaga i tektonskog kontakta foraminiferskih vapnenaca dviju antiklinalnih struktura suprotnih vergencija (sl. 20, pretpostavljeni profil). realna situacija takvog profila je u predjelu vitre, na sjeveroistoënoj padini vinodola (sl. 4, profili j, k). njihov razvoj moæe se objasniti boranjem i rasjedanjem u okviru subdukcijskog procesa (sl. 21). u takvom sluëaju, gdje u tektonski kontakt mogu doêi istoznaëno orijentirana krila dviju primarno paralelnih antiklinalnih struktura, vrlo je teπko terensko uoëavanje rasjeda i determiniranje struktura. na temelju navedenih primjera mogu se donijeti i odree186 geologia croatica 52/2 ni zakljuëci πireg znaëenja. ovisno o obliku paraklaza uzduænih rasjeda, odnosno nagibu relevantnog dijela plohe, a koji se moæe znatno mijenjati po pruæanju uz fiziëke osobitosti stijena u dodiru i karakteru osnovnog kretanja, rezultirat êe u uæoj subdukcijskoj zoni (s) sekundarne strukturne deformacije, razliëite po obliku te horizontalnom i vertikalnom domaπaju. one gotovo izostaju u podinskom krilu akcije (a): ono se ponaπa kao strukturno jedinstveni kompleks, jedino dislociran u blokove popreënim i dijagonalnim rasjedima. razmatrajuêi promjenu smjera i veliëine nagiba relevantnog dijela rasjedne plohe istog karakteristiënog oblika, uz uglavnom istoznaënu rezultantu pritiska rotacijskog podvlaëenja zone podinskog krila akcije (a), moæe se pretpostaviti model deformacija (sl. 20). iz njega je vidljivo da se poveêanjem veliëine nagiba segmenta rasjedne plohe sve do okomitog poloæaja, u uæoj zoni subdukcije (s) poveêavaju deformacije s obzirom na strukturni oblik, πirinu kompleksa zahvaêenog deformacijama kao i dubinu odnosno debljinu kompleksa. daljnjem poveêanju nagiba iznad 90° (prebaëenom dijelu segmenta; promjena smjera nagiba uz smanjenje veliëine), odgovara porast intenziteta strukturnih promjena s obzirom na oblik i vertikalni domaπaj, ali se smanjuje njihov horizontalni domet. kontinuirani tijek razvoja struktura razliëitih karakteristika i dometa u uæoj zoni subdukcije (s) a po pruæanju uzduænog graniënog rasjeda, najëeπêe je naruπen djelovanjem brojnih popreënih i dijagonalnih rasjeda. ti rasjedi, preteæno radijalni i u pravilu s horizontalnim kretanjem, presijecaju primarne strukture (a i r) ili njihove dijelove, a javljaju se kao posljedica podvlaëenja. uzimajuêi u obzir odreenu autonomnost u kretanju i ponaπanju stijena krajnjih zona (a i r), moguêe je pretpostaviti i odvojenost sustava tih rasjeda u zoni podinskog krila akcije (a) i zoni krovinskog krila otpora (r). u srediπnjoj, uæoj zoni subdukcije (s) dolazi do njihovog mijeπanja. upravo zahvaljujuêi kretanjima uz takve preteæno vertikalne rasjede potencirana su u njihovom domaπaju osnovna kretanja podvlaëenja, uz istovremeno znatnu promjenu elemenata rasjednih ploha na kontaktu s uæom zonom subdukcije (s). sliëna analiza te interpretacija postanka i karakteristika struktura na dodiru uæe zone subdukcije (s) i krovinskog krila otpora (r), kao i u samom krovinskom krilu, t.j. fliπne doline i sjeveroistoëne karbonatne padine, nije u cijelosti moguêa. iako se i ovdje susreêu sliëni elementi, kao πto su u pravilu rasjedni kontakti jedinica u dodiru, reversni karakter rasjedanja, karakteristiëni oblik rasjedne plohe, postoje i razlike: to su u prvom redu nejedinstvenost rasjednog kontakta i razliëiti intenzitet tektonskog poremeêaja, a time i razliëiti oblici strukturnih deformacija i njihov vertikalni i horizontalni domet u stijenama krovinskog krila otpora (r) i uæe zone subdukcije (s). navedene razlike nisu samo posljedica osobitosti podvlaëenja i otpora krovinskog krila (r) i oblika rasjedne plohe, veê u prvom redu paleostrukturne odnosno konsekventne paleogeomorfoloπke razvedenosti danaπnjeg, na prvi pogled jedinstvenog kompleksa krovinskog krila otpora (r) i uæe zone subdukcije (s). naime, niz neposrednih i posrednih podataka upuêuje na postojanje primarnih boranih struktura unutar tektonski suæene fliπne doline i karbonatnih stijena obiju strana doline. to je i prikazano na tektonskoj skici ovog podruëja (sl. 22). od direktnih pokazatelja mogu se navesti: prebaëena izoklinalna antiklinala sjeveroistoëne strane vinodola, t.j. strukturna jedinica belgrad-griæane, duboko uvlaëenje fliπnih naslaga u podruëju diran s dijelom sinklinalnim poloæajem slojeva, antiklinalni oblik foraminiferskih vapnenaca uzviπenja maliê, u jugoistoënom dijelu strukturne jedinice ropci-maliê, nalaz mlaeg nivoa eocenskih klastita u provalijama vitra i pihlja, gornjokredna antiklinala zapadno od vitre, kao dio strukturne jedinice petrinoviêi-kriæiπêe, sinklinalni poloæaji eocenskog fliπa istoëno i zapadno od tektonskog prodora odnosno primarno antiklinalne strukture gornjokrednih i foraminiferskih vapnenaca drivenika. dalje, u πirem podruëju triblja, na borane strukture unutar fliπa upuêuju podaci buπenja na profilu podsopaljsuπik, a u neposrednoj blizini utvrene su antiklinalne strukture foraminiferskih vapnenaca na humcu (kota 102) i vapnenaëko-laporovitih eocenskih sedimenata kod podsoplja. izoklinalnim borama tumaëene su i pojave foraminiferskih vapnenaca u predjelu kamenjak (»ubrilovi∆, 1938) i sjeveroistoëno od kamenoloma badanj. meu indirektnim pokazateljima su nalazi mlae razine eocenskih klastita, na potezima pihlja-vitra i u produæetku predjela diran preko naselja antovo-belgrad-griæane. smjeπteni su u indiciranim sinklinalama. njihov smjeπtaj postaje logiëan ukoliko sinklinalne strukture u odreenom vremenskom intervalu shvatimo kao paleogeomorfoloπka korita kanale intenzivnijeg i usmjerenog transporta materijala. i lokacija naselja, uz pojavu niza izvora, posredno upuêuje na ëvrπêu vapnenaëku podlogu tanjeg fliπnog pokrivaëa u tjemenim dijelovima antiklinalnih struktura. uvaæavajuêi iznesene podatke i promatrajuêi ih po povrπini moæe se pretpostaviti sinklinorijski strukturni oblik srednjoeocenskog fliπnog bazena na prostoru vinodola. recentno pruæanje bora je pribliæno sjever-sjeverozapad jug-jugoistok. odreene strukturne osobitosti i lokacija podataka govore u prilog niza paralelnih i dijelom eπaloniranih brahiantiklinala i brahisinklinala. »eoni dijelovi brahistruktura uglavnom nisu saëuvani; jug-jugoistoëni su degradirani rotacijskim podvlaëenjem podinskog krila akcije, t.j. uz jugozapadni vinodolski rasjed (4). sjever-sjeveroistoëna ëela preteæno sinklinalnih struktura skrivena su rasjednim kontaktima susjednih antiklinala. na shematiziranoj palinspastiëkoj rekonstrukciji prikazan je raspored brahistruktura s osnovnim naznakama lokaliteta recentnog reljefa (sl. 23). istaknute su strukture s veêom odnosno manjom debljinom fliπnih sedimenata, t.j. relativnim odnosom amplituda svijanja, kao i predjeli pretpostavljeno s dominacijom karbonatnih stijena. kao vremenski okvir prikaza uzet je interval izmeu taloæenja eocenskog fliπa i mlae razine krupnoklastiënih eocenskih sedimenata. polazeêi od tako zacrtane slike rasprostranjenosti primarnih plikativnih struktura, u uvjetima subdukcijskog procesa i otpora u krovinskom krilu otpora (r) i pripadajuêem dijelu uæe zone subdukcije (s) moguêe je i objaπnjenje pojedinih struktura. pri tome je nuæno uzeti u obzir fiziëke osobitosti klastiënih i karbonatnih stijena i njihovu podatljivost odreenom tipu strukturnih promjena. jednako je tako vaæna i njihova debljina kao i primarni strukturni oblik. naime, debljem kompleksu klastita jedne ili viπe paralelnih sinklinala, izloæenom subdukcijskom kretanju uglavnom okomitom na pruæanje struktura, u dodiru sa stabilnijim antiklinalnim karbonatnim kompleksom krovinskog krila otpora (r), odgovarati êe jedinstveni, jednoznaëni tektonski kontakt tipa reverznog rasjeda blaæe poloæene paraklaze ili “navlaka”. takav kontakt nalazimo u jugoistoënom dijelu istraæivanog podruëja u vidu rasjeda kozak (3), izmeu strukture belgrad187blaπkoviê: tectonics of part of the vinodol valley within the model of the continental crust subduction griæane i najπireg fliπnog podruëja doline. nasuprot tome, manjoj debljini klastiënog kompleksa, odnosno poveêanju utjecaja kompaktnijih karbonatnih stijena, πto odgovara pliêim sinklinalama odnosno izraæenijim antiklinalama, u uvjetima istog subdukcijskog procesa, u krovinskom krilu otpora (r) i dijelom u uæoj zoni subdukcije (s) odgovarat êe, ovisno o broju sinformi, reverzni rasjedni kontakti sa strmim do gotovo okomitim rasjednim plohama. sinklinalni dijelovi struktura su u podinskim krilima rasjeda. izmeu navedena dva gotovo krajnja sluëaja postoji postupan prijelaz, ovisan o debljini klastiënog kompleksa, toënije veliëini sinklinalnog svijanja. oëituje se u postupnoj promjeni nagiba paraklaze reverznog (reverznih) rasjeda i veliëini vertikalnog kretanja. u uvjetima eπaloniranog rasporeda ëela primarnih antiklinala, a prema sinklinorijskom prostoru, moguêe je oëekivati stapanje dva ili viπe rasjeda u jedinstveni reverzni rasjed, kako je zabiljeæeno u strukturnim jedinicama sjeveroistoëne strane vinodola (kriæiπëe-petrinoviêi i ropci-maliê) na njihovom kontaktu s fliπnim naslagama doline. na drugoj pak strani, sa zatvaranjem sinklinalne strukture, u ëelu, reverzni rasjed s moguênoπêu prijelaza u rasjed s okomitom paraklazom moæe postupno nestati ili prijeêi u koljeniëastu boru, sve slabije izraæenu u produæetku (sl. 7). i kao konaëan rezultat tektonskih promjena, opisanim procesima u primarno sinklinorijskim uvjetima na dodiru sa stabilnijom antiklinalnom strukturom, formirane su, u karbonatnom kompleksu krovinskog krila otpora (r), t.j. sjeveroistoënoj strani vinodola, tangencijalne strukture izoklinalnih, prebaëenih i kosih antiklinala te reverznih rasjeda s jugozapadnom vergencijom. dodir s uæom zonom subdukcije (s), t.j. fliπnom dolinom, oznaëen je reverznim rasjedanjem, uz jedinstvenu blago poloæenu paraklazu rasjeda kozak i stopljenu rasjednu zonu (kriæiπêe-ropci-suπik-janjevalj), strmo odnosno strmije poloæene rasjedne plohe. u fliπnoj dolini (uæa zona subdukcije s), kao posljedica kretanja krajnjih zona (s i r), dominiraju strukture sinklinala i antiklinala s promjenom vergencije, jugozapadne uz sjeveroistoëni rub, do sjeveroistoëne vergencije uz jugozapadni rub vinodola. u samoj dolini izrazita asimetrija rasporeda pojedinih kronostratigrafskih jedinica, dijelom struktura i njihovog hipsometrijskog poloæaja potvruju podvlaëenje jugozapadne strane vinodola (a), a izdizanje sjeveroistoëne strane vinodola (r). evo najznaëajnijih podataka. gornjopliocenske taloæine smjeπtene su u tektonski zatvorenim strukturama uglavnom u hipsometrijski najniæim predjelima i to samo uz jugozapadni rub vinodola. hipsometrijski poloæaj rasjednih kontakata izmeu preteæno eocenskog fliπa i karbonatnih stijena na stranama doline je razliëit. zamjetljivo je viπi uz reverzne rasjede sjeveroistoënog ruba vinodola u odnosu na visinu kontakta uz reverzni jugozapadni vinodolski rasjed (tablica 1). uz iste rasjedne kontakte vezane su i kvartarne sipariπne breëe (tablica 1). indikativne su njihove debljine i strukturni poloæaj. minimalna debljina (1-5 m) i rasprostranjenost kvartarnih sipariπnih breëa uz jugozapadni vinodolski rasjed, kao i nagib slabo izraæenih slojeva (38-44° sl. 24a), posljedica su dijelom rotacijskog podvlaëenja jugozapadnog krila rasjeda, t.j. podinskog krila akcije (a). nasuprot tome, uz sjeveroistoëne rasjede doline maksimalna je debljina (10-25 m) i povrπina sipariπnih breëa. to govori u prilog ne samo intenziteta tektonskih promjena veê i karaktera pokreta, u smislu izdizanja karbonatnih stijena koje su dale materijal sipariπta. zajedno s izdizanjem karbonatnog kompleksa, t.j. krovinskog krila otpora (r), uz istovremeno strukturno oblikovanje, izdiæe se i sjeveroistoëni dio fliπnog kompleksa doline, t.j. uæe zone subdukcije (s). tome u prilog govori ne samo hipsometrijski poloæaj rasjednog/rasjednih kontakta veê osobito kut nagiba slojeva kvartarnih sipariπnih breëa. isti je izmjeren na pozajmiπtima materijala (petrinoviêi, ropci, franoviêi i dr.) i iznosi 15-20° odnosno horizontalan je ili ëak s blagim nagibom prema sjeveroistoku (sl. 24b). dakle znatno manji nego prirodni kut nagiba recentnog sipara. grafiëki prikaz razvoja opisanih odnosa predoëen je na slici 25. 5. vremenski slijed strukturnog oblikovanja poëetne strukturne deformacije smjeπtaju se u okvir laramijskih pokreta na prijelazu kreda-tercijar. ti pokreti su shvaêeni kao svojevrsna najava dezintegracije karbonatne platforme u ovom dijelu dinarida, a naπli su odraza u formiranju blagih antiklinalnih i sinklinalnih struktura s konsekventnim reljefom te emerziji. nastavak mobilnosti u ovom podruëju, tijekom dijela paleocena, manifestira se labilnoπêu izraæenijih sinklinalnih struktura, a dokumentiran je taloæenjem kozinskih ili njima sliënih naslaga u tim strukturama odnosno depresijama. taloæenje foraminiferskih vapnenaca (kontinuirano na kozinskim naslagama ili veêim dijelom transgresivno na gornjokrednim vapnencima) predstavlja relativno miran vremenski period, a odgovara uglavnom donjem eocenu. meutim, promjena sedimentacije iz karbonatnih preko prijelaznih naslaga u klastiëne fliπne sedimente, generalno u lutetu, no u pojedinim podruëjima ili u odreenim dijelovima istog podruëja i znatno ranije, upuêuje na ponovno aktiviranje tektonskih pokreta. oni su, u poëetnoj fazi, shvaêeni kao daljnje plikativne deformacije veê postojeêih boranih struktura ali s izraæenijom labilnoπêu sinklinalnih-utonulih dijelova, a praêeni su intenzivnijom sedimentacijom klastiënih naslaga. meutim, i sama subsidencija labilnih sinklinalnih dijelova bora veê u ovoj poëetnoj fazi nosi osobitosti subdukcijskog kretanja: tonjenje labilne zone je asimetriëno (na πto ukazuje danaπnji poloæaj kozinskih naslaga), pa se premjeπta os bazena maksimalne sedimentacije fliπnih naslaga, suprotno smjeru osnovnog kretanja. utvrena mlaa razina konglomeratiëno-pjeπëanih naslaga u vinodolu, poistovjeêena s prominskim naslagama, kao i njihov diskordantni odnos prema fliπnim sedimetima (bla©kovi∆ & ti©ljar, 1983), upuêuje na prethodno pojaëanu tektonsku aktivnost, sada veê s jasno izraæenim subdukcijskim kretanjem: asimetriënim izdizanjem antiklinalnog sklopa u zaleu (krovinsko krilo otpora r) i spuπtanjem sinklinalnih struktura (uæa zona subdukcije s) uz popratne plikativne strukturne promjene sa sve izraæenijim naginjanjem. moæe li se uz ove pokrete vezati i postanak vapnenaëkih breëa (konglomerata) ekvivalenata jelarskih naslaga (bahun, 1974), pretpostavljenih u vinodolu (bla©kovi∆ & ti©ljar, 1983), ostaje otvoreno pitanje sve do odreivanja toënog kronostratigrafskog poloæaja tih naslaga. no, u tom smislu valja navesti i neka opaæanja. iako utvrene na malim udaljenostima, fosiliferne kongomeratiëno-pjeπëane prominske naslage i ekvivalenti jelarskih naslaga, znatno se razlikuju po sastavu i veliëini zrna. u prvima, vapnenaëki materijal je rijetko zastupan, dominira materijal udaljenijih matiënih klastiënih i kristalinskih stijena. vapnenaëke breëe i konglomerati jelarskih naslaga izgraeni su gotovo iskljuëivo od ulomaka (i slabo zaobljenih valutica) krednih i foraminiferskih vapnenaca neposredne podloge ili iz male udaljenosti. veliëina fragmenata jelarskih naslaga uveliko nadmaπuje promjer valutica i zrna konglomeratiëno-pjeπëanih naslaga. 188 geologia croatica 52/2 upravo navedene znaëajne razlike u izvornim stijenama, duæini transporta, te granulometrijskom sastavu, govore u prilog nove faze intenzivnijih tektonskih kretanja. njima je prekinut donos materijala za taloæenje konglomeratiëno-pjeπëanih prominskih naslaga, a omoguêena brza i intenzivna sedimentacija gruboklastiënih jelarskih naslaga, kao, dakle, u ovom podruëju mlaeg tektogenetskog kompleksa. o daljnjem slijedu tektonskih pokreta moæemo donositi zakljuëke tek na temelju podataka vezanih uz mlae pliocenske i kvartarne taloæine. mlae pliocenske glinovito-pjeskovite naslage poznate su u ovom dijelu vinodola na lokalitetima podsopalj (koch, 1922) i badanj (»ubrilovi∆, 1938), a imale su i znatniju rasprostranjenost u dolini (bla©kovi∆, 1983). na lokalitetu badanj pliocenske taloæine su u reversnom rasjednom kontaktu s paleogenskim foraminiferskim vapnencima uz rasjednu plohu nagnutu prema sjeversjeveroistoku (20°) pod kutem od 53°. za interpretaciju vremena, a osobito karaktera tektonskih kretanja poseban znaëaj ima novi nalaz istovrsnih gornjopliocenskih naslaga u “ponikvi” jugozapadno od vrha sopalj (kota 321) na visini od 225 metara. izdanci pak pliocenskih naslaga u dolini na lokalitetu podsopalj, na najveêoj su nadmorskoj visini od 100-155 m. razlika u hipsometrijskom poloæaju tih naslaga posljedica je naknadnih kretanja: spuπtanja, tonjenja jugozapadnog dijela doline uz istovremeno izdizanje, asimetriëno boranje i popreëno rasjedanje krednopaleogenske antiklinale izmeu vinodola i mora. prijevoj izmeu obje pojave pliocenskih naslaga, s nadmorskom visinom od 285 metara, izgraen od antiklinalno svijenih gornjokrednih i paleogenskih vapnenaca, a koji za 60 metara nadvisuje pliocenske naslage “ponikve”, govori u prilog i postpliocenskog asimetriënog boranja uz istovremeno izdizanje. karakteristike kvartarnih sipariπnih breëa, kao πto su sastav, debljina, smjeπtaj te osobito strukturne osobitosti, pruæaju znaëajne podatke o tektonskim pokretima u istraæivanom podruëju u tom vremenskom intervalu (bla©kovi∆, 1983). prije navedene veliëine nagiba slojeva siparnih breëa, uz rasjede sjeveroistoënog i jugozapadnog ruba vinodola, odstupaju od prirodnog kuta nagiba sipara. ublaæavanje nagiba ili ustrmljivanje moglo je uslijediti tek poslije djelomiëne cementacije siparnog materijala, kao i formiranje dviju stepenica ploëa siparnih breëa, jedne viπe u predjelu griæane-papiêi i druge niæe dolinci-barci. upravo to govori o vremenu tektonske aktivnosti tijekom kvartara. interpretacija tektonskih pokreta govori u prilog zadræavanja karaktera osnovnog kretanja (sl. 25). naime, mala koliëina sipariπnih breëa na jugozapadnoj padini vinodola, i njihov iznenaujuêe veliki kut nagiba, u podudarnosti su s rotacijskim kretanjem u spuπtanju podinskog krila akcije (a) jugozapadnog karbonatnog ruba, i tendencijom spuπtanja i fliπnih naslaga doline neposredno uz kontakt. zahvaljujuêi takvom kretanju poveêava se nagib slojeva sipariπnih breëa. nasuprot tome, izdizanje sjeveroistoëne karbonatne padine vinodola krovinskog krila reakcije (r), a osobito strukturne deformacije koje to izdizanje prate, uzrok su i izdizanju odnosno “istiskivanju” plastiënih preteæno laporovitih naslaga fliπa u uæoj zoni kontakta. a istiskivanje fliπne podloge siparnih breëa smatra se uzrokom promjena nagiba slojeva breëa u smislu ublaæavanja. za konaëna razmatranja vremena tektonskih promjena nuæno je ponoviti i navode o mlaoj razini kvartarnih sipariπnih breëa (bla©kovi∆, 1983). na gotovo horizontalno poloæenim starijim vapnenaëkim breëama kod franoviêa, diskordantno leæe siparne vapnenaëke breëe, s nagibom prema jugozapadu pod kutom od 35-45°. meusobni poloæaj ova dva paketa, po sastavu gotovo identiënih siparnih breëa, jedini je podatak za njihovo odjeljivanje. na temelju iznijetog podatka nedvojbeno proizlazi da su se najintenzivnija tektonska kretanja, odluëujuêa za konaëno strukturno oblikovanje vinodola, odvijala poslije taloæenja gornjopliocenskih naslaga a tijekom kvartara i praêena su ogromnim koliëinama siparnog materijala. u kvartaru tektonska aktivnost istog stila nalazi odraza u strukturnim deformacijama siparnih breëa i njihove podloge, a time i geomorfoloπkim karakteristikama vinodola. »esta pojava potresa, mjestimiëno intenzivna erozija (slani potok), kao i neki znakovi aktivnog kretanja uz rasjedne linije (uëestala oπteêenja istih dionica komunikacija i suhozidina) govore u prilog i danas prisutnih tektonskih kretanja. nalaze izraza i u reljefu vinodola (sl. 26). 6. zaklju»ak u dijelu vinodola, gdje su relativno dobro poznati geoloπki sastav i graa, obavljena su istraæivanja i prezentiran je sadræaj otprije poznatih i novoutvrenih rezultata, koji se odnose na rasprostranjenost i razvoj kronostratigrafskih jedinica i strukturne elemente. to se posebno odnosi na nove podatke o rasprostranjenosti eocenskih fliπnih naslaga i necjelovitosti sjeveroistoëne vapnenaëke padine vinodola, te nalaz mlae pliocenskih naslaga u vapnenaëkom kompleksu izmeu vinodola i mora u hipsometrijski znatno viπoj poziciji od onih u samom vinodolu. tektonski odnosi i rekonstrukcija njihova slijeda do formiranja recentnih odnosa (grae), kao teæiπte rada, promatrani su kroz procese kontinentalne subdukcije, na temelju modela udruæenih zona podvlaëenja (bla©kovi∆ & aljinovi∆, 1981). podruëje vinodola shvaêeno je kao jedna od zona podvlaëenja i istovremeno kao nositelj osobitosti procesa plitke subdukcije πireg znaëenja. u rekonstrukciji procesa izdvojena su tri elementa: podinsko krilo akcije (a), krovinsko krilo reakcije (r) i uæa zona subdukcije (s). oni odgovaraju paleogeografskim odnosno paleostrukturnim jedinicama: krilo akcije izdignutoj antiklinalnoj ili monoklinoj strukturi u podvlaëenju, a krilo reakcije takoer izdignutoj antiklinalnoj strukturi pod koju se odvija podvlaëenje. izmeu njih je, primarno, sinklinalna-sinklinorijska struktura konsekventnog reljefa, izrazite labilnosti kao uæa zona subdukcije. osnovna karakteristika procesa podvlaëenja je u vertikalnoj rotaciji suprotnog predznaka krajnjih dijelova: spuπtanja krila akcije i izdizanja krila reakcije. u meuprostoru, uæoj zoni subdukcije, nastavlja se ista tendencija. rezultat kinematskog procesa je u formiranju struktura razliëitog tipa i intenziteta poremeêaja. tako u pojasu tektonskog dodira podinskog krila akcije (a) i uæe zone subdukcije (s) o obliku rasjedne plohe (veliëina i smjer nagiba) ovisi oblik te vertikalni i horizontalni domet strukturnih deformacija. u pojasu dodira pak krovinskog krila reakcije (r) i uæe zone subdukcije (s), u konkretnom sluëaju sloæenih paleostrukturnih odnosa dominiraju sustavi eπaloniranih i stopljenih helikoidalnih rasjeda reverznog pa i navlaënog karaktera. promjene intenziteta strukturnih deformacija duæ oba kontakta nisu postupne, veê do njih dolazi uz popreëne i uglavnom dijagonalne rasjede s dominantnim horizontalnim kretanjem krila. navedeni rasjedi uglavnom su autonomni za krajnje segmente u procesu podvlaëenja u uæoj zoni subdukcije uglavnom prestaje njihova aktivnost. trase tih rasjeda su vrlo ëesto predisp onirane ëelima eπaloniranog rasporeda antiklinalnih struktura. geodinamski proces navedenih promjena moæe se vremenski odrediti u 3 faze: 1) laramijskim pokretima su formi189blaπkoviê: tectonics of part of the vinodol valley within the model of the continental crust subduction rane blage borane strukture konsekventnog reljefa; 2) pirenejskim pokretima u eocenu kao i pokretima u nastavku formirane su tangencijalne borane i rasjedne strukture; 3) one dobivaju svoj recentni domet oæivljenim kretanjima posebno u kvartaru. zahvale zahvaljujem dr. ivi veli∆u na poticaju i kritiëkim primjedbama, te prof. dr. giovanni battista carulliju na pregledu i korisnom savjetu u pripremi rada. izvanrednu pomoê pruæio mi je doc. dr. bruno safti∆, posebno u pripremi i korigiranju engleskog teksta. takoer zahvaljujem kolegici jasmini obho–a© na trudu uloæenom u izradi crteæa, te mom susjedu iz antova (vinodol) gosp. mihi jer»inovi∆u, kao pratiocu u terenskim istraæivanjima. 190 geologia croatica 52/2 cvetkovic.indd 115 � ab stra ct the kloštar oil fi eld is situated in the northern part of the sava depression within the croatian part of the pannonian basin. the major petroleum reserves are confi ned to miocene sandstones that comprise two production units: the lower pontian i sandstone series and the upper pannonian ii sandstone series. we used well logs from two wells through these sandstones as input data in the neural network analysis, and used spontaneous potential and resistivity logs (r16 and r64) as the input in network training. the fi rst analysis included prediction of lithology, which was defi ned as either sandstone or marl. these two rock types were assigned categorical values of 1 or 0 which were then used in numerical analysis. the neural network was also used to predict hydrocarbon saturation in selected wells. the input dataset was extended to depth and categorical lithology. the prediction results were excellent, because the training and prediction dataset showed little disagreement between the true and predicted values. at present, this study represents the best and most useful application of neural networks in the croatian part of the pannonian basin. keywords: kloštar fi eld, neural network, prediction, sandstone, hydrocarbon saturation, croatia application of neural networks in petroleum reservoir lithology and saturation prediction � marko cvetković1, josipa velić1 and tomislav malvić1,2 1 department of geology and geological engineering, faculty of mining, geology and petroleum engineering, pierottijeva 6, 10000 zagreb, croatia; (marko.cvetkovic@rgn.hr) 2 development department, oil & gas exploration and production, ina-industrija nafte d.d., šubićeva 29, 10000 zagreb, croatia; (tomislav.malvic@ina.hr) doi: 10.4154/gc.2009.10 geologia croatica 62/2 115–121 6 figs. 2 tabs. zagreb 2009 geologia croaticageologia croatica 1. introduction we used data from the kloštar oil fi eld in croatia to test the application of neural networks as a part of a project with a cro ati an oil company (ina). the only other geomathematical tools used on this oil fi led were several interpolation methods used for porosity mapping (balić et al., 2008). the fi eld is located approximately 35 km east of the croatian capital of zagreb (fig. 1). this particular fi eld was selected because it is part of a joint research project between the faculty of mining, geology and petroleum engineering, and a croatian oil company. we used neural network analysis to predict reservoir lithology of the i and ii sandstone series as either shale or sandstone, as well as the hydrocarbon saturation of the sandstone intervals. these intervals are generally represented by clastic, brackish to freshwater deposits that are characteristic of the upper pannonian and lower pontian succession throughout the croatian part of the pannonian basin (lučić et al., 2001). 2. petroleum geology settings the dinaric oriented (nw–se) križ structure (including the kloštar fi eld) is located at the most northwestern part of moslavačka gora mountain. despite many available well data, the borders of the stratigraphic units are commonly not precisely defi ned, mostly because of a lack of palaeontological samples and complex tectonics resulting in many tectonic blocks. at favorable locations, stratigraphic boundaries are determined based on available well data, including cores, mud chips, and logs. the following fi ve units are defi ned and degeologia croatica geologia croatica 62/2 116 the pliocene deposits, i.e., dacian and romanian, are also locally known as the paludina beds. these sediments are characterized by the alternation of clays and medium and coarse-grained sands. quaternary deposits consist predominantly of yellowish sandy clays with abundant lime concretions. the average thickness ranges between 10 and 15 m. the kloštar structure is a faulted anticline with dinaric strike (nw–se). the geological history appears interesting, as shown by investigations of structural settings and the tectonic evolution of the western part of the sava depression (velić, 1979, 1980, 1983). the fi eld structure was formed in the middle miocene, when intensive badenian and sarmatian uplifting events resulted in formation of a nw to seoriented anticline of 7×2 km. later, in the late miocene, this structure was differentiated in two smaller parts: the northern, which was uplifted during the pontian, and the southern, which was only activated during the upper pontian. the recent structural shape was tectonically created during the pliocene and quaternary, when the main phase of hydrocarbon migration probably occurred. 3. artificial neural networks a neuron is a basic element of a network that is mathematically presented as a point in space toward which signals are transmitted from surrounding neurons (fig. 2). the value of a signal on the activity of a neuron is determined by a weight factor multiplied by a corresponding input signal. the total input signal is determined as a summation of all products of weight factor multiplied by the corresponding input signal given by 1 ( ) n i ji j j u w input = = ⋅σ , scribed below, based on these boundaries: palaeozoic, middle miocene, upper miocene, pliocene, and quaternary sediments. the basement of the tertiary system represents the core of the križ structure. it includes extrusive igneous and metamorphic rocks, including granites of palaeozoic age (vragović & mayer, 1980). this formation is a buried hill, formed by radial tectonic movements and denudation processes that occurred before the miocene epoch. the rocks are weathered and fractured. in structurally favourable places, hydrocarbon accumulations are confi rmed. the middle miocene (badenian, sarmatian) unit unconformably overlies the palaeozoic igneous–metamorphic complex. the basal part is characterized by coarse-grained conglomerates, conglomeratic sandstones, and sandstones often intercalated with shale. it is overlain by dark-gray, sandy, bituminized marls, partially intercalated with lightgray, fi ne-grained sandstones. miocene beds form economic hydrocarbon reservoirs at the southern and eastern parts of the kloštar structure. upper miocene (pannonian, pontian) strata are well documented throughout the fi eld area. lower pannonian strata conformably overlie sarmatian bituminized marls. upper pannonian sediments are represented by predominantly brown or dark-gray calcareous marls and sandstones, located in the southwestern part, and partially saturated by hydrocarbons. they are defi ned as the ii sandstone series. lower pontian sediments are represented by dark-gray, massive marls and sandy marls to the south and east of the fi eld area. sandstones, mostly arenites with minor proportions of marl or clay, are dominant in the northwest and are partially saturated with hydrocarbons. the lower pontian sandstones are also called the ii sandstone series. the upper pontian succession is monotonous, consisting of soft sandy or clayey sediments and the proportion of sand increases upward. fi gu re 1: geographic position of the kloštar fi eld in croatia. geologia croaticacvetković et al.: application of neural networks in petroleum reservoir lithology and saturation prediction 117 where n represents the number of inputs for the neuron i. if the total input signal has a value greater than the sensitivity threshold of a neuron, then it will have an output of maximum intensity. alternatively, a neuron is inactive and has no output. value of the output is given by ( )i i ioutput f u t= ⋅ , where f represents the activation function and ti, the targeted out put value of neuron i. one can fi nd a more detailed des crip tion of neural network basics and methods in mccul lo ch & pitts (1943), rosenblatt (1958) and anderson & rosenfeld (1988). the basic architecture of a neural network consists of neurons divided into layers. three is a minimum number of layers which a neural network has to have. these layers are the input layer, the hidden layer and the output layer. the input layer is for accepting signals, or in our case, input variables. these data are transferred to the hidden layer where it is processed by the activation function belonging to the neurons within it. data which proved to be signifi cant in the analysis in the hidden layer neurons is sent to the output layer as the resulting data for the predicted variable. the number of hidden layers can be more than one or strictly one, depending on the type of the neural network. for example, the multi layer perceptron (mlp) neural network is basically designed to be able to have more than one hidden layer and to perform better with two or three hidden layers than with one. in opposition to the multi layer perceptron, the radial basis function (rbf) neural network can only have one hidden layer but the number of neurons within this layer is much larger than the number of neurons in the single hidden layer of the mlp. for this analysis, we used the two aforementioned types of neural networks, the supervised learning-multilayer perceptron and the radial basis function neural network. the mlp network is based on a back propagation algorithm which calculates the error surface gradient in each step of the analysis. in the following step, the weight factors are adjusted according to the earlier calculated error surface gradient so the error minimizes and a new error surface is calculated. also, the network can utilize a two-phase learning with second learning algorithms such as conjugate gradient descent (gorse et al., 1997), quasi-newton (bishop, 1995), levenberg–marquardt (levenberg, 1944; marquardt, 1963), quick propagation (fahlman, 1988) and delta-bar-delta (jacobs, 1988) which basically work on similar principles to the back propagation algorithm with a somewhat different approach. the greatest advantage of these aformentioned algorithms over the back propagation is that they are signifi cantly faster but sometimes the standard back propagation algorithm gives the best results. for more information in croatian on these learning algorithms please refer to the geostatistical dictionary of malvić et al. (2008). the mlp is more successfully applied in classifi cation and prediction problems (rumelhart et al., 1986), and is the most often used neural network in solving geological problems. the rbf network is also a commonly used neural network but is more successfully and frequently applied in solving classifi cation problems than in solving prediction problems. neural networks have been successfully applied in petroleum geology problems such as determining reservoir properties (e.g., lithology and porosity) from well logs, (bhatt, 2002) and well-log correlation (luthi & bryant, 1997). in the croatian part of the pannonian basin, only a few petroleum geology research projects have been performed. in these studies, clastic facies were determined from well logs (malvić, 2006) and porosity was predicted based on well and seismic data (malvić & prskalo, 2007). 4. data analysis we used well log data from two wells as input data for the neural network analysis. the data consist of the most basic well logs because measurements were taken in 1956 (well klo–a) and 1957 (well klo–b). although these logs were taken some 50 years ago, we can successfully use them for interpretation (fig. 3). available data for analysis included resistivity (r16 and r64) and spontaneous potential (sp) logs. resolution of the data was 10 cases (measurements) per metre of well log. we performed two types of analysis. first we predicted the lithology, followed by the hydrocarbon saturation. we carried out the analysis such that the neural network was fi rst trained on a specifi c interval of well log data (overseen learning), and afterward we used the trained neural network to predict the value of desired parameters for the intervals on which the neural network was not trained. all neural network analysis were made using statsoft statistica 7.1. fi gu re 2: artifi cial neuron model. geologia croatica geologia croatica 62/2 118 4.1. lithology prediction to predict lithology, we manually determined the lithological component by distinguishing layers of marl and sandstone from well logs (bassiouni, 1994) on wells klo–a and klo–b. the neural network was trained on the fi rst set of data, which includes intervals that correspond to the i sandstone series, and the prediction was made on the intervals that correspond to the ii sandstone series and vice versa. input data for training of the neural network, resistivity (r16, r64) and sp logs, were used. we defi ned lithology as a categorical variable (1 for sandstone, 0 for marl). for training of the neural network, we used manually determined lithology. results described in the tables represent the success of the neural network training. values are shown as training error and prediction error. the program in which the analyses were made automatically divides the training dataset into two parts, the length of which is user defi ned. the fi rst set is used for training of the neural network; the second, for testing the neural network’s ability to predict cases. this kind of data distribution minimizes the risk of overtraining. the training procedure is stopped when user-defi ned conditions have been met (fi nal number of iterations or desired amount of error) or when the program decides that further training will no longer yield better results. results of neural network training for the prediction of lithology are given in table 1 and expressed as two error values in percentages. the training error corresponds to the previously mentioned dataset that was used for training the neural network. the selection error describes the neural network’s success for predicting the values on unknown data. two neural networks were trained for each well, one mlp and one rbf network. here the prediction could only be done on the deeper or shallower parts of the well log in the same well; cross-prediction or 2d neural network analysis did not yield satisfactory results here because of the different values of sp logs in the two wells. table 1 shows that both of the neural networks have been successfully trained on the corresponding interval. the anomaly is shown in table 1, where the mlp network showed a high training error but low selection error. initially one might presume that the rbf network with signifi cantly lower training error is more successful in predicting the unknown data interval, but this is not the case. the mlp network had slightly better results than the rbf, so we conclude that the value of the selection error is a much more reliable indicator of success of a neural network than the training error is. thus, when neural network training is fi nished, the best network parameters are the ones with the smallest selection errors. the relationship between manually determined lithology and lithology gained from neural network analysis is shown in figs. 4 and 5. 4.2. hydrocarbon saturation prediction as opposed to lithology prediction, hydrocarbon saturation prediction uses cross-prediction. the neural network is trained on one well log interval, much larger than in the former prediction case. training had been done on one well, klo–a, and prediction had been performed on another well, fi gu re 3: part of the klo–b well log representing the interval for the i sandstone series. table 1: neural network parameters for lithology prediction neural network type and propertiesa well training errorb selection errorb rbf 3–31–1 klo-a 0.152942 0.172753 mlp 3–4–6–3–1 klo-a 0.31438 0.133478 rbf 3–13–1 klo-b 0.156621 0.149185 mlp 3–6–4–2–1 klo-b 0.255012 0.214935 a neural network type and properties correspond to the type of network and number of neurons per layer where fi rst and last number represent the properties of the input and output layer. values between these represent the number and properties of the hidden layers. b error value ranges from 0 to 1, where 0 represents 100% success of prediction, i.e., no error. geologia croaticacvetković et al.: application of neural networks in petroleum reservoir lithology and saturation prediction 119 klo–b. for input data we used resistivity logs (r16, r64), sp logs, corresponding data about well depth and lithology, and the hydrocarbon saturation value. hydrocarbon saturation was manually determined from resistivity log r64. the corresponding data well depth gave better results in this neural network performance than in lithology prediction, where it had little or no effect. hydrocarbon saturation value, as well as lithology, was defi ned as a categorical value. here “1” stands for positive hydrocarbon accumulation and “0” for fi gu re 4: comparison of mlp neural network predicted (dotted line) and manually determined data (solid line) in lithology prediction analysis for well klo–a. the diagram’s abscissa represents vertical depth, and the ordinate represents the value of lithology expressed as either marl (0) or sandstone (1). fi gu re 5: comparison of rbf neural network predicted (dotted line) and manually determined data (full line) in lithology prediction analysis for well klo–b. the diagram’s abscissa represents vertical depth, and the ordinate represents the value of lithology expressed as either marl (0) or sandstone (1). table 2: neural network parameters for hydrocarbon saturation prediction neural network type and propertiesa training errorb selection errorb mlp 5–6–8–1 0.056897 0.091173 a neural network type and properties correspond to the type of network and number of neurons per layer where the fi rst and last numbers represent the properties of the input and output layer. values between these represent the number and properties of the hidden layers. b error value ranges from 0 to 1, where 0 represents 100% success of prediction, i.e., no error. geologia croatica geologia croatica 62/2 120 negative. for this analysis, only the mlp neural network was used because an rbf network was characterized by a high selection and training error. neural network parameters are shown in table 2. relationships between manually determined and neural network predicted hydrocarbon saturation are shown in fig. 6. 5. discussion generally, for all neural network analyses, the more input cases and more input variables used, the more successful the results and the better prediction will be. prediction of the lithology has proven reliable only when the extrapolation of data was within one well interval. in this analysis the most signifi cant value was the sp log. with the input of resistivity logs alone, correspondence between true and predicted values was not satisfactory. also, the input logs were recorded in 1956 and 1957. a problem that appeared in this study, which prohibited cross-prediction of lithology, was different sp log values for wells klo–a and klo–b. the rm for klo–a was 72 ωm for mud temperature of 13°c and 625 ωm for klo–b with a mud temperature of 1°c. this problem led to unsuccessful prediction in the shallower part of the well log data interval, where electric properties of mud on wells klo–a and klo–b were signifi cantly different, and to successful prediction in the deeper part of the well log data interval (>850 m of depth), where values were similar on both corresponding well log data intervals. this problem probably occurred because of the different electrical properties of mud, infl uenced by different temperature values and the composition of the mud itself. in deeper segments of the well, temperature and electrical properties of mud on both wells were normalized, and therefore cross-prediction on deeper intervals was possible. one solution to this problem for shallower intervals could be introducing lithology descriptive variables that are not as dependent on mud properties as the sp log. for example, gamma ray logs as well as other well logs that defi ne reservoir properties, such as compensated neutron and density logs, could be used to obtain better neural network performance. 6. conclusions in this study, we trained several artifi cial neural networks with the task of predicting the lithology of upper pannonian sediments (ii sandstone series) and lower pontian deposits (i sandstone series), as well as hydrocarbon saturation within these beds. sandstone facies are adequate media for statistical and neural network analysis. our analysis of sandstone reservoirs of the kloštar fi eld by neural tools yielded the following results: when determining the lithological component in wells klo–a and klo–b with rbf and mlp neural networks, we achieved excellent correspondence between true and predicted values. prediction of hydrocarbon saturation in well klo–b with a neural network trained in well klo–a gave excellent correspondence between true and predicted values. our results show the great potential of neural networks’ application in petroleum geology research, where they could be used to quickly acquire results from well logs, to obtain vertical and lateral correlation of such logs, and to solve other petroleum geology problems. fi gu re 6: comparison of mlp neural network predicted (dotted line) and manually determined data (solid line) in hydrocarbon saturation analysis in wells klo–a and klo–b. the diagram ordinate represents hydrocarbon saturation (0 or 1), whereas the abscissa represents the corresponding data depth. geologia croaticacvetković et al.: application of neural networks in petroleum reservoir lithology and saturation prediction 121 references anderson, j.a. & rosenfled, e. (1988): neurocomputing: foundations of research.– mit press, cambridge, 729 p. balić, d., velić, j. & malvić, t. (2008): selection of the most appropriate method for sandstone reservoirs in the kloštar oil and gas fi eld.– geol. croat., 61/1, 27–35. bassiouni, z. (1994): theory, measurement, and interpretation of well logs.– society of petroleum engineers, richardson, 372 p. bhatt, a. (2002): reservoir properties from-well logs using neural networks.– unpubl. phd thesis, ntnu, trondheim, 151 p. bishop, c.m. (1995): neural networks for pattern recognition, 1st edition.– oxford university press, new york, 504 p. fahlman, s.e. (1988): faster learning variations on back-propagation: an empirical study.– proceedings of the 1988 connectionist models summer school, los altos, 38–51. gorse, d., shepherd, a. & taylor, j.g. (1997): the new era in supervised learning.– neural networks, 10/2, 343–352. jacobs, r.a. (1988): increased rates of convergence through learning rate adaptation.– neural networks, 1, 295–307. levenberg, k. (1944): a method for the solution of certain problems in least squares.– quardt. appl. math., 2, 164–168. lučić, d., saftić, b., krizmanić, k., prelogović, e., britvić, v., mesić, i. & tadej, j. (2001): the neogene evolution and hydrocarbon potential of the pannonian basin in croatia.– mar. petrol. geol. 18/1, 133–147. luthi, s.m. & bryant, i.d. (1997): well-log correlation using a back-propagation neural network.– math. geol. 29/3, 413–425. malvić, t. (2006): clastic facies prediction using neural network (case study from okoli fi eld).– nafta, 57/10, 415–431. malvić, t. & prskalo, s. (2007): some benefi ts of the neural appro ach in porosity prediction (case study from beničanci fi eld).– nafta 58/9, 455–467. malvić, t., cvetković, m. & balić, d. (2008): geomatematički rječnik [geomathematical dictionary].– hrvatsko geološko društvo (hgd), zagreb, 74 p. marquardt, d.w. (1963): an algorithm for least-squares estimation of nonlinear parameters.– j. soc. indust. appl. math. 11/2, 431–441. mcculloch, w.s. & pitts, w. (1943) a logical calculus of ideas immanent in nervous activity.– b. math. biol. 5/4, 115–133. rosenblatt, f. (1958): the perceptron: a probabilistic model for information storage and organization in the brain.– psychol. rev. 65/6, 386–408. rumelhart, d.e., hinton, g.e. & williams, r.j. (1986): learning internal representations by error propagation.– in: rumelhart, d.e. & mcclelland, j.l. (eds.): parallel distributed processing, mit press, cambridge, 1, 381–362. velić, j. (1979): o razlikovanju neotektonskih, struktura u zapadnom dijelu savske depresije [distinguishing the neotectonic structures in western part of sava depression – in croatian].– geol. vjesnik, 31, 175–183. velić, j. (1980): geološka građa zapadnog dijela savske depresije [geological settings of the western part of sava depression – in croatian].– unpubl. phd thesis, faculty of mining, geology and petroleum engineering, zagreb, 139 p. velić, j. (1983): neotektonski odnosi i razvitak zapadnog dijela savske potoline [neotectonic relations and development of the western part of sava depression – in croatian].– acta geol. 13/2, 26–65. vragović, m. & majer, v. (1980): prilozi za poznavanje metamorfnih stijena zagrebačke gore, moslavačke gore i papuka (hrvatska) [samples for recognition of metamorphic rocks of zagrebačka gora, moslavačka gora and papuk mountain (croatia) – in croatian].– geol. vjesnik, 31, 295–308. manuscript received december 16, 2008 revised manuscript accepted may 15, 2009 available online june 19, 2009 bisevac.indd 63 � vanja biševac1, dražen balen1, darko tibljaš1 and darko španić2 ab stra ct samples from the radlovac metamorphic complex, together with others from the overlying sedimentary rocks, and parts of psunj metamorphic complex beneath it were studied in order to better constrain metamorphic conditions that have prevailed in the area. rocks from mt. papuk were investigated, in order to determine thermal conditions, by kübler index (illite “crystallinity”) and árkai index (chlorite “crystallinity”) while the b0-parameter of k-white mica was used to estimate the pressure conditions. treatment with dimethyl-sulfoxide (dmso) was used in order to extend application of chlorite “crystallinity” measurements to kaolinite bearing samples. results suggest temperatures between 250–300°c and pressures of 2–3 kb. similar temperature data recorded from various lithologies implies the existence of a previously unknown post lower triassic thermal event, (alpine very low to low-grade metamorphism) affecting different complexes on mt. papuk. new data presented and discussed in this paper provides the basis for further research and interpretation of the tectono-metamorphic history of the studied area and its correlation with other similar european metamorphic complexes. keywords: tisia, mt. papuk, very low to low-grade metamorphism, kübler index, árkai index, b0-parameter, dmso treatment, geothermobarometry 1 university of zagreb, faculty of science, horvatovac bb, hr-10000 zagreb, croatia; (vabisevac@geol.pmf.hr) 2 research and development sector, ina – industrija nafte d. d. – corporate processes, lovinčićeva bb, h-10000 zagreb, croatia preliminary results on degree of thermal alteration recorded in the eastern part of mt. papuk, slavonia, croatia geologia croatica 62/1 63–72 6 figs. 3 tabs. zagreb 2009 geologia croaticageologia croatica � 1. introduction the pannonian basin, surrounded by the mountain ranges of the alps, the carpathians and the dinarides, is the young depression fi lled predominately with thick neogene sediments. the basement of the pannonian basin is formed of crystalline rocks separated into two major units: the alcapa composite mega-unit and tisia mega-unit (pamić & jurković, 2002; haas & péró, 2004). the tisia mega-unit represents a large lithosphere block with complex internal structure. it is made up of variscan crystalline complexes in the basement and post-variscan-alpine overstep sequences. tisia mega-unit outcrops occur in the slavonian mountains (psunj, papuk, krndija) (fig. 1), the south transdanubian ranges (mecsek, villány hills) and the apuseni mountains (bihor, pădurea craiuli, codru-moma, higniş) (pamić & jurković, 2002). the best outcrops of tisia, which can aid the interpretation of the geological history of this mega-unit, occur in mt. papuk (e.g. csontos, 1995, pamić & jurković, 2002; pamić et al., 2002), and comp rise a very low to medium grade polimetamorphic complex, together with migmatization and granitoid magmatism (pamić & lanphere, 1991). mt. papuk’s variscan crystalline complexes can be generally divided into two groups: 1. low and medium-grade metamorphic rocks in combination with migmatites and granitoids and juxtaposed 2. very low-grade metamorphic rocks with metabasics (metadiabase and metagabro) pamić & jamičić, 1986; pamić, 1998. geologia croatica geologia croatica 62/1 64 a very low-grade metamorphic complex, called the radlovac metamorphic complex (jamičić, 1983, 1988) or semi metamorphic complex (pamić & lanphere, 1991) occupies the highest structural position of all variscan complexes, and is covered by permo-triassic and triassic sediments (jamičić & brkić, 1987; jamičić, 1983, 1988). the main aim of this paper is to increase the current knowledge of the metamorphic conditions to which rocks of mt. papuk have been subjected, by studying rocks belonging to the radlovac metamorphic complex as well as the overlying sedimentary rocks and parts of the psunj metamorphic complex. although several researchers (jamičić, 1983, 1988; slovenec, 1986; pamić & lanphere, 1991) have indicated particular p–t conditions, at least for some parts of the radlovac metamorphic complex, further research is necessary. for this purpose, a multidisciplinary approach which includes optimal laboratory methods based primarily on x-ray diffraction was used. in order to determine thermal conditions, rocks were investigated by kübler index (illite “crystallinity”) and árkai index (chlorite “crystallinity”), while the b0-parameter of k-white mica was used for estimating the pressure conditions. new p-t data presented in this paper will form the basis for further research, especially age dating on illite fractions, and interpretation of the tectono-metamorphic history of the studied area and its correlation with other similar european metamorphic complexes. 2. geological settings the slavonian mts. situated in slavonia, (the northeastern region of croatia), represent some of the best outcrops of crystalline basement of the tisia mega-unit (pamić et al., 1996; pamić & jurković, 2002). this mega-unit represents the continental fragment broken off from the southern rim of the eurasian plate (i.e. from the southern margin of the variscan europe) during the alpine evolution of tethys (géczy, 1973). after complex drifting and multiple rotations during mesozoic and cenozoic times, the tisia unit occupied its present tectonic position (csontos, 1995; stampfli et al., 2002). in the slavonia region, jamičić (1983, 1988), distinguished three tectono-metamorphic complexes, characterized by several phases of deformation and metamorphism: (1) psunj metamorphic complex (also named the kutjevo metamorphic series), was assumed to have been formed by metamorphic events during the baikalian orogeny. the psunj metamorphic complex comprises (a) greenshists facies metamorphic sequences composed of metapelites, chlorite schists and micashists, and (b) amphibolite facies sequences composed of paragneisses, garnetiferous micashists, amphibolit es, metagabbros and marbles, locally intruded by discordant granodiorites and plagiogranites (i.e. i-type granites according to pamić, 1986; pamić & lanphere, 1991); (2) papuk metamorphic complex (also named the jankovac metamorphic series), which was subjected to metamorphism and migmatitization during the caledonian orogeny. the papuk metamorphic complex consists mostly of (a) s-type granites which are symmetrically surrounded from the ne and sw sides by zones of (b) migmatites and migmatitic gneisses which grade into (c) amphibolite facies metamorphic sequences composed of garnetiferous amphibolites, paragneisses and micashists (pamić, 1986; pamić & lanphere, 1991) and (3) radlovac metamorphic complex which underwent very low-grade metamorphism during the variscan orogeny. the radlovac metamorphic complex consists of very lowgrade, (sub-greenshist facies) metamorphic sequences mostly composed of slates, metagreywackes, metaconglomerates and subordinate phyllites. the lower and middle parts of the complex are intruded by sills of metadiabase and ophitic metagabbro (pamić & jamičić, 1986). according to jamičić (1983, 1988) and jamičić & brkić (1987) this very low to low-grade metamorphic complex occupies the highest structural position in the pre-alpine complexes from the slavonian mts., and originally represented the carboniferous (brkić et al., 1974) or late silurian to early permian (jerinić et al., 1994) sedimentary cover over the psunj metamorphic complex. it is uncomformably overlain by a clastic-carbonate succession of late permian and triassic age, which is not affected by alpine metamorphism (jamičić & brkić, 1987). based on extensive petrological analysis in combination with radiometric age dating of plutonic and metamorphic rocks, pamić & lanphere (1991) gave an alternative subdivision (see also pamić & jurković, 2002 and references therein) according to which only two complexes can be distinguished. they proposed that the psunj (kutjevo) and papuk (jankovac) complexes, distinguished by jamičić (1983, 1988), in fact represent one coherent magmatic-metamorphic complex. the second complex is the radlovac complex. 3. materials and methods 3.1. macroand microscopic characteristics of the studied samples ten samples, which were chosen in this pilot study in order to cover rocks with different petrological characteristics and age, which according to jamičić & brkić (1987) range from late precambrian (pcm) to the early triassic (t1) (table 1), were analyzed by several techniques. chlorite schist (sample 1), is a grey to green foliated metamorphic rock with abundant phyllosilicate minerals. the well observed schistosity is defi ned by dominant chlorite and mica (illite-muscovite) together with fi ne-grained recrystallized quartz (fig. 2a). chlorite schist belongs to the psunj metamorphic complex (ps). chloritoid schists (samples 2 and 3) are dark grey, fi negrained metamorphic rocks with well observed schistosity defi ned by their dominant grano-lepidoblastic matrix (fig. 2b). the main minerals of the matrix are quartz and subordinate sericite (“white mica”). prismatic chloritoid porphyroblasts up to 0.5 mm, randomly oriented, occur in the fi negrained matrix. chloritoids have a distinct postkinematic character as already seen by pamić & lanphere (1991). chloritoid schists characteristically show microfolds with the geologia croaticabiševac et al.: preliminary results on degree of thermal alteration recorded in the eastern part of mt. papuk, slavonia, croatia 65 foliation transposed along microfold axial plains. chloritoid schists belong to the d3 zone (jamičić & brkić, 1987). metapsammite (sample 4) is a grey to silvery coarsegrained rock with blastopsammitic texture. weakly recrystallized detrital quartz predominates, while subordinate plagioclase is abundant in a fi ne-grained matrix of sericite and recrystallized quartz (fig. 2c). micaceous minerals and elongated quartz grains have a subparallel orientation. metapelites (samples 5 and 6) are reddish or green with blastopelitic texture. continuous cleavage and foliation defi ned by fi ne-grained micaceous material and elongated quartz grains are clearly observed (fig. 2d). these metapelites and metapsammite belong to the radlovac metamorphic complex (ra). phyllitic conglomerates (samples 7 and 8) are dark reddish to brown. they contain primarily well-rounded pebbles of quartz and subordinate granites and weathered schists. the matrix contains fi ne-grained recrystallized quartz, sericite, chlorite and haematite (fig. 2e). the matrix shows a distinct cleavage developed parallel to the surface layering. quartz sandstone (sample 9) is a white, fi ne-grained rock in which continuous schistosity defi ned by parallel grains of mica and quartz is well observed (fig. 2f). the matrix is composed of sericite with subordinate quartz cement. as pointed out by jamičić et al. (1983, 1987), the observed schistosity is probably a consequence of multiple tectonic movements in the area. sandstone (sample 10) is white in colour. the rock is very compact, hard, and mainly composed of round grains of quartz embedded in a fi ne-grained matrix of quartz and sericite (fig. 2g). phyllitic conglomerates and quartz sandstones belong to the permo-triassic and the sandstone to the triassic sedimentary cover (s) – (jamičić & brkić, 1987). 3.2. modal composition whole rock powder xrd analysis of the samples was performed at the institute of mineralogy and petrology, university of zagreb on a philips x’pert pro diffractometer equipped with an x’celerator detector using cukα radiation from tube operated at 40 kv and 45 ma. the step width was 0.017°2θ with 43 s counting time per step; the samples were run between 4 and 65 °2θ. fi gu re 1: (a) the position of tisia mega-unit within the pannonian basin and (b) sketch map of slavonian mts. (psunj, ravna gora, papuk and krndija) with an approximate position of the studied area (marked in the black box). table 1: geographical setting, rock type and stratigraphic age of studied samples (ps – psunj metamorphic complex; ra – radlovac metamorphic complex; s – permo-triassic and triassic sediments) together with whole rock modal composition of the studied samples determined by xrd. mineral abbreviation are after kretz (1983): qtz – quartz; ill – mus (illite–muscovite); pl – plagioclase; kfs – k-feldspar; chl – chlorite; cld – chloritoid; prl – pyrophyllite; hem – haematite; kln – kaolinite; mineral quantity: dominant:++++; abundant:+++; signifi cant:++; poor:+ lithology (macroscopic determination) sample numbers gauss-krüger coordinates geological complex age modal composition (jamičić & brkić, 1987) qtz ill-mus pl kfs chl cld prl hem kln sandstone 10 6489786e 5037679n s t1 ++++ +++ + ++ + quartz sandstone 9 6489952e 5037405n s 2pt +++ ++++ ++ + + phyllitic conglomerate 8 6489999e 5037000n s 1pt +++ ++++ + ++ + phyllitic conglomerate 7 6486289e 5038970n s 1pt +++ ++++ + ++ + metapelite 6 6482989e 5038898n ra c, p +++ ++++ ++ ++ + metapelite 5 6485299e 5039996n ra c, p ++++ ++ +++ + metapsammite 4 6485258e 5039488n ra c, p +++ ++++ ++ +++ chloritoid schist 3 6490363e 5036446n d3 +++ ++++ + + + +++ ++ chloritoid schist 2 6490197e 5036595n d3 ++++ ++ + + + +++ chlorite schist 1 6490725e 5036000n ps pcm ++++ +++ ++ +++ + a b geologia croatica geologia croatica 62/1 66 3.3. kübler index (illite “crystallinity”) and árkai index (chlorite “crystallinity”) the kübler index (ki) and árkai index (ái) are widely applied for determining the grade of diagenesis and low temperature regional metamorphism of clastic (pelitic-silty-marly) rocks, which are usually devoid of metamorphic indicator minerals and assemblages (kübler, 1967, 1990; árkai 1991, árkai et al., 1995). methodological approach describing use of ki and ái in this paper is the same as in judik et al. (2004; 2006). illite and chlorite “crystallinity” can be expressed by different indices and the most common ones are the kübler and árkai, respectively. they are both defi ned as the full width at half maximum (fwhm) of the illite (10 å) and chlorite (7 å and 14 å) x-ray diffraction maxima, measured on the <2μm fraction of a highly oriented air dried clay specimen using cukα radiation (kübler, 1964, 1967, 1968, 1984; kübler & jaboyedoff, 2000; árkai, 1991). both indices are expressed as °∆2θ cukα radiation. values of ki and ái diminish with increasing metamorphic grade. the agreed boundary between the diagenetic zone and anchizone at present is at ki=0.42 δ°2θ while for the anchi zone to epizone limit, it is ki=0.25 δ°2θ. these boundaries are associated with temperatures of approximately 200 and 300 °c respectively (kübler, 1968; warr & rice, 1994). the anchizone is further divided into high and low anchizone. the boundary between these two zones is ki= 0.30 δ°2θ corresponding to a temperature of approximately 260°c (potel et al., 2006). the boundaries of the anchi zone for the árkai index were taken from árkai et al. (1995) and are: ái (001) =0.26–0.37 δ°2θ and ái (002)=0.24–0.30 δ°2θ. fi gu re 2: characteristic textural features of the analyzed samples: a – chlorite schist; b – chloritoid schist; c – metapsammite; d – metapelite; e – phyllitic conglomerate; f – quartz sandstone and g – sandstone. see text for details. mineral abbreviations are the same as in table 1. geologia croaticabiševac et al.: preliminary results on degree of thermal alteration recorded in the eastern part of mt. papuk, slavonia, croatia 67 sample preparation was undertaken according to the recommendation of kisch (1991) and the fwhm was read manually. “illite fraction” i.e. fraction <2μm, obtained using a centrifuge (tehtnica–centric 322a), was used for ki and ái measurements. the xrd measurements were carried out on a philips x’pert pro diffractometer with a graphite monochromator at the institute of mineralogy and petrology, university of zagreb. instrumental conditions were 40 kv, 40 ma and constant time 5 s, with step scanning (0.02 °2θ). ki and ái were measured on air-dried samples and no shift of the basal white mica refl ection after ethylene-glycol (eg) treated was observed, so the results are discussed using only the air-dried scan results. the standardization of ki and ái values of samples measured in the laboratory, to those of kübler’s laboratory, taken as referent values, was made using eight kisch standards i.e. rock slabs polished parallel to the dominant orientation of phyllosilicate i.e. parallel to the foliation (kisch, 1990; 1991). the equation representing this case, used here for standardization of the ki and ái values of all samples except chlorite schist to the referent kübler’s values, is as follows: ki (kübler) = 0.9684 x ki (zagreb) + 0.0757 r2=0.9844 (eq. 1) the same equation was used to obtain kübler values for warr & rice (1994) standards, and the values obtained are listed in table 2. these cis standards were used again for monitoring changes in measured fwhm caused by tube ageing. for further explanation see also kisch et al. (2004). 3.4. dimethyl-sulfoxide (dmso) treatment the presence of kaolinite in the samples can make the ái (002) measurement very diffi cult and uncertain because of the overlapping of the (001) diffraction maximum of kaolinite and the (002) diffraction maximum of chlorite. they both have diffraction maxima at ~12.4 °2θ i.e. ~7.2 å. in order to get a reliable ái value, an attempt was made to separate these two diffraction maxima, using treatment with dmso. this treatment should separate the maxima one apart from another and shift the (001) diffraction maximum of kaolinite to higher d values (from ~7.2 å to ~11.3 å) (calvert, 1984). treated samples were measured using standard ki and ái measuring conditions. 3.5. total organic carbon (toc) it is usual to correlate ki and ái indices with other parameters which alter with thermal conditions changes, including vitrinite refl ectance. with this aim toc was measured in order to fi nd out if the investigated samples are suitable for such kind of analyzes and to fi nd an appropriate correlation. the measurements were made in the ina – laboratory for geochemistry, with samples prepared according to bush (1970). standardization of the instrument (leco ir–212) was undertaken using material of known carbon content (a steel ring containing 0.3–1.0 % carbon). 3.6. b0-parameter the b0-parameter in k-white micas is controlled by pressure (sassi, 1972, guidotti & sassi, 1986). the geobarometric b0-parameter is measured as 6×d(060,331̄) of muscovite. this parameter monitors the relative pressure environments of very low to incipient low-grade metamorphic terrains and is widely used as a relative geobarometer for interregional comparisons (sassi & scolari, 1974). the analytical procedure is based on work by sassi (1972) and sassi & scolari (1974) with further development by guidotti & sassi (1986). sassi’s (1972) qualitative geobarometer is based on the b0-parameter value, or more precisely, 6×d(060,331̄) spacing of k–na white micas, which refl ects the increasing celadonite substitution that occurs in muscovite with the pressure increase in the al-rich portion of the nonlimiting muscovite–albite assemblage (wang et al., 1996; rieder et al., 1998). the good linear correlation between the value of 6×d(060,331̄) and the celadonite content has been well demonstrated by guidotti et al. (1989). using the procedures defi ned by sassi & scolari (1974), each sample was cut perpendicular to its schistosity. quartz present within the samples was used as an internal standard. the diffractometric analyses were carried out directly on these slices using the aforementioned xrd at same conditions used for ki and ái determination, ensuring in all cases that the area exposed to x-rays was phyllosilicate rich. the 2θ range scanned was 59.0–63.0°. 4. results 4.1. modal composition the whole rock powder xrd analysis (table 1) revealed that quartz and illite–muscovite are the main constituent minerals in all samples. chlorite was found in chlorite schist, chloritoid schists, metapelites, metapsammite, phyllitic conglomerates and quartz sandstone. k-feldspar was detected in chloritoid schists, quartz sandstone and sandstone, while plagioclase is present in all samples except for the quartz table 2: obtained values for warr & rice (1994) standards used for monitoring changes in measured fwhm caused by tube ageing, together with equivalent kübler’ s referent values. for further explanation see also kisch et al. (2004). cis – crystallinity index standards; ki – kübler index; ad – air dried standard (warr & rice, 1994) cis ki (ad) (warr & rice, 1994) °δ2θ ki (ad) °δ2θ our laboratory ki (ad) kübler referent values using eq. 1 °δ2θ ki (ad) our laboratory for this paper °δ2θ sw 1 0.63 0.449 0.511 0.423 sw 2 0.47 0.285 0.352 0.274 sw 4 0.38 0.286 0.353 0.263 sw 6 0.25 0.213 0.282 0.190 mf 1 0.11 0.122 0.194 0.056 geologia croatica geologia croatica 62/1 68 sandstone. additionally, haematite was detected in chlorite schist, phyllitic conglomerates and metapelite, chloritoid in both chloritoid schists, pyrophyllite in chloritoid schist and kaolinite in quartz sandstone and sandstone. 4.2. kübler index (illite “crystallinity”) and árkai index (chlorite “crystallinity”) the ki and ái results are shown in table 3. ki was measured for all samples and ái only for samples containing chlorite in suffi cient quantity. the lowest ki, which indicates the highest thermal alteration, was measured on phyllitic conglomerate (0.238 °∆2θ). the highest ki, which indicates the lowest thermal alteration, was measured on chloritoid schist (0.291 °∆2θ). árkai indices (001) and (002) range from 0.221 °∆2θ (phyllitic conglomerate) to 0.243 °∆2θ (chlorite schist) and from 0.224°∆2θ (metapsammite) to 0.283°∆2θ (phyllitic conglomerate), respectively. the ái (002) probably has a narrower range due to the fact that the two highest values were obtained from samples with low chlorite content (fig. 3). therefore peaks were low and measurements are less precise. fi gu re 3: graphical representation of the degree of thermal alteration according to the data of kübler and árkai indices shown in table 2 for: (a) ki (001), (b) ái (001) and (c) ái (002). ki and ái values are expressed in °δ2θ (cukα). boundaries of the anchizone were taken from kübler (1968, 1990) for ki and from árkai et al. (1995) for ái. “e” – epizone; “ha” – high anchizone; “la” – low anchizone; “d” – diagenetic zone; n.m.=not measured; weak=diff raction maximum was not suitable for ái measurement. table 3: kübler index (ki) and árkai index (ái) measured on <2 μm grainsize air-dried mounts together with the total organic carbon (toc) content in the studied samples. ki and ái values are expressed in δ°2θ (cukα). (the (001) diff raction maximum of chlorite of metapelite, phyllitic conglomerate and quartz sandstone was too weak and therefore not suitable for árkai index measurement. this was also the case for both diff raction maxima of chlorite for the chloritoid schists. the árkai index of sandstone was not measured (n.m.) because this sample does not contain chlorite.) *ái determined after treatment with dmso. sample ki (001) ái (001) ái (002) toc (%) sandstone 0.247 n.m. n.m. 0.00 quartz sandstone 0.259 weak 0.274* 0.00 phyllitic conglomerate 0.238 weak 0.283 0.00 phyllitic conglomerate 0.262 0.221 0.232 0.00 metapelite 0.253 weak 0.242 0.01 metapelite 0.249 0.234 0.241 0.02 metapsammite 0.284 0.223 0.224 0.00 chloritoid schist 0.291 weak weak 0.08 chloritoid schist 0.287 weak weak 0.13 chlorite schist 0.244 0.243 0.265 n.m. a b c geologia croaticabiševac et al.: preliminary results on degree of thermal alteration recorded in the eastern part of mt. papuk, slavonia, croatia 69 4.3. dimethyl-sulfoxide (dmso) treatment after treatment of the “illite fraction” in the quartz sandstone (i.e. fraction <2μm), with dmso shift of (001), a diffraction maximum of kaolinite towards higher d values (~7.2 to ~11.1 å) was observed (fig. 6). the position of the (002) diffraction maximum of chlorite remained unchanged. in this way (002) diffraction maximum of chlorite becomes more symmetric and therefore suitable for ái determination. 4.4. b0-parameter the measurements of the b0-parameter were made on 2 metapelites discussed in this paper and an additional 10 samples from radlovac metamorphic complex which satisfy the criteria set by sassi and scolari (1974). the average b0parameter value is 8.993 å (n=12), with a standard deviation of 0.012. the majority of the values fall between 8.980 and 9.006 å (66% of analyzed samples), two samples have b0values higher than 9.006 å and two samples had a b0-parameter value lower than 8.980 å (fig. 4). 4.5 total organic carbon (toc) total organic carbon was not found or was very low in all investigated samples (table 2). samples containing less than 0.5% toc for clastites and 0.3% toc for carbonates are, according to hunt (1995), not suitable for vitrinite refl ectance measurements. 5. discussion according to the kübler and árkai indices (table 3, fig. 3) all analyzed samples show a certain degree of thermal alteration recorded within the “illite fraction”. obtained values of ki and ái indicate thermal alteration ranging from the low temperature part of the high anchizone (approximately 250 °c) to the low temperature part of the epizone (approximately 300 °c) i.e. sub-greenschist to greenschist facies (fig. 3). these data are in good agreement with the previously established presence of paragonite and pyrophyllite reported by slovenec (1986) in some slates from the radlovac metamorphic complex. according to frey (1986) these minerals are characteristic of sub-greenschist facies and indicate, as well as kübler and árkai indices measured here, that the radlovac metamorphic complex recorded the younger metamorphic overprint of very low to low-grade metamorphic temperature conditions (biševac et al., 2007). samples from the psunj metamorphic complex (ps) which fi gu re 4: pressure conditions estimation based on the b0-parametar for samples from the radlovac metamorphic complex obtained from k–white micas of k-feldspar-free rock slices (1– 12) together with the average b0-value for this paper (13) and average b0values taken from pamić & lanphere (1991) (14). the boundaries between the low, intermediate and high pressure fi elds are from árkai et al. (1991). fi gu re 5: variation of the kübler index data with stratigraphic age. sample numbers are the same as in table 1. (“e” – epizone, “ha” – high anchizone; “la” – low anchi zone; “d” – diagenetic zone). geologia croatica geologia croatica 62/1 70 occurs below the radlovac metamorphic complex, as well as those from the overlying sediments (s) recorded the same very low to low-grade metamorphic event of the same temperature conditions (approximately 250–300 °c according to ki and ái). since effects of this metamorphism are barely visible without the aid of instrumental techniques, we will not designate these deposits to be metasediments. pressure conditions estimated on the basis of the b-parameter of k-white mica (average value for analyzed samples is 8.993 å) (fig. 4) indicate that samples from the radlovac metamorphic complex recorded a metamorphic event of low to intermediate pressure conditions of sub-greenshists to greenshists facies. the measured b0-parameter corresponds to approximately 2–3 kb (sassi & scolari, 1974; guidotti & scolari, 1986; árkai et al., 1991; árkai et al., 1995). although pamić & lanphere (1991) point ed out that their measurements of the b0-parameter of kwhite mica were made on a small population of samples (average value for 10 samples was 9.002 å), their results, which indicate the lowest intermediate pressure (~3 kb) (fig.4), are in good agreement with the data presented here. it is important to mention that both ki and ái can provide more reliable results if samples with similar lithology are compared. usually fi ne-grained clastic rocks are suggested in the literature for such purposes. in course grained samples, the effects of inherited (detrital) phyllosilicates may overlap and strongly modify the nature of authigenic (metamorphic, newly -formed) micas and chlorites (árkai, 1983; 1991; 1995). this is valid even if the <2μm fraction of samples is used (árkai et al., 1981; árkai, 1983). in order to confi rm that the thermal maturity of the studied samples, especially permo-triassic quartz sandstone and triassic sandstone, is really the result of alpine tectonism, further investigation of the illite fraction is in progress. despite the fact that the analyzed samples clearly differ from one another by their stratigraphic age, protolith, mineral composition and texture, no signifi cant infl uence of these parameters to ki values was observed. the degree of thermal alteration seems to be constant through the whole analyzed column (fig. 5). all this data points to the conclusion that the analyzed samples recorded the same event which can be dated as younger than the early triassic. the extensive k–ar dating of suitable illite fractions is in progress and preliminary report points to the cretaceous (biševac et al., 2007). the appearance of ordered kaolinite in some samples (table 1) was connected to post-metamorphic hydrothermal alteration which probably occurred during uplift of the basin and it is not connected with the metamorphic overprint reported here. 6. conclusions (1) ki and ái measured on samples belonging to the radlovac metamorphic complex as well as parts of psunj metamorphic complex and d3 metamorphic rocks indicate a thermal overprint ranging from the low temperature part of the high anchizone (approximately 250 °c) to the low temperature part of the epizone (approximately 300 °c) i.e. sub-greenschist to greenschist facies. (2) the clastic-carbonate sedimentary succession (phyllitic conglomerates, quartz sandstone and sandstone) of the late permian and triassic age, which uncomformably overlies the radlovac metamorphic complex was also affected by the same thermal overprint. (3) pressure conditions estimated on the basis of the b0-parameter of k-white mica (average value is 8.993 å) indicate that samples from the radlovac metamorphic complex were metamorphosed under the low to intermediate pressure of the sub-greenshists to greenshists facies (approximately 2–3 kb). (4) total organic carbon (toc) in all samples was either absent or very low. (5) the degree of thermal alteration i.e. the kübler index, tend to be constant through the whole analyzed column fi gu re 6: x-ray diff raction patterns (4–14 °2θ cukα) of quartz sandstone (2pt) (fraction <2μm) before and after treatment with dmso. mineral abbreviations are the same as in table 1. geologia croaticabiševac et al.: preliminary results on degree of thermal alteration recorded in the eastern part of mt. papuk, slavonia, croatia 71 implying that the different complexes (ps, d3, ra and s) all record the same, post early triassic metamorphic overprint. (6) dmso treatment enabled chlorite “crystallinity” measurements of kaolinite containing samples by separating 001 and 002 diffraction peaks of kaolinite and chlorite respectively. acknowledgement the authors thank prof. dr. peter árkai (geochemical institute, budapest, hungary) and dr. domagoj jamičić (croatian geological survey, zagreb, croatia) for constructive criticism in reviews and comments that helped to improve the manuscript signifi cantly. we thank prof. hanan j. kisch (department of geology and mineralogy, ben-gurion university of negev, beer-sheva, israel) for providing a set of standards necessary for instrument calibration in this study. this study was supported by the ministry of science, education and sports, project no. 119-1191155-1156 and croatian–hungarian scientifi c bilateral project ‘metamorphic evolution of crystalline basement complexes in the area of the pannonian basin and the internal dinarides’. references árkai, p. (1983): very lowand low-grade alpine regional metamorphism of the paleozoic and mesozoic formations of the bükkium, ne hungary.– acta geol. hung., 26, 83–101. árkai, p. (1991): chlorite crystalinity: an empirical aproach and correlation with illite crystalinity, coal rocks of northeast hungary.– j. metamorph. geol. 9, 723–734. árkai, p., horváth, z. & tóth, m. (1981): transitional very low and low grade metamorphism of the paleozoic formations, uppony mountains, ne–hungary: mineral assemblages, illite crystallinity, –bo and vitrinite refl ectance data.– acta geol. acad. sci. hung., 24, 265–294. árkai, p., sassi, r., zirpoli, g. (1991): on the boundary between the lowand low-grade south-alpine basement in pustertal: x-ray characterization of the wkite mica in metapelites between dobbiaco (toblach, italy) and leiten (austria) (eastern alps).– memorie di scienze geologische, university of padova, xliii, 293–304. árkai, p., sassi, f.p., sassi, r. (1995): simultaneous measurement of chlorite and illite crystallinity: a more reliable tool for monitoring lowto very low-grade metamorphism in metapelites. a case study from the southern alps (ne italy).– eur. j. mineral., 7, 1115–1128. biševac, v., balogh, k., balen, d. & tibljaš, d. (2007): new data on metamorphic event in the eastern part of mt. papuk, slavonia, croatia.– in: rocha, f., terroso, d. & quintela, a. (eds.): euroclay 2007, abstract book, univer sidade de aveiro, 75–76. brkić, m., jamičić, d. & pantić, n. (1974): karbonske naslage u papuku (sjeveroistočna hrvatska) [carboniferous deposits in mount papuk (northeastern croatia) – in croatian].– geol. vjesnik, 27, 53–58. bush, p.r. (1970): a rapid method for determination of carbonate carbon and organic carbon.– chem. geology, 6, 59–62. calvert, c.s. (1984): simplifi ed, complete cssl-hydrazine-dimethylsulfoxide intercalation of kaolinite.– clay. clay. miner., 32, 125– 130. csontos, l. (1995): tertiary tectonic evolution of the intra-carpathian area: a review.– acta vulcanol., 7, 1–13. frey, m. (1986): very-low grade metamorphism of alps–an introduction.– schweiz. mineral. petrogr. mitt., 66, 13–27. géczy, b. (1973): the origin of the jurassic faunal provinces and the mediterranean plate tectonics.– ann. univ. sci. budapest, eötvös nom. sect. geol., 16, 99–114. guidotti, c. & sassi, f. (1986): classifi cation and correlation of metamorphic facies series by means of muscovite b0 data from lowgrade metapelites.– n. jb. mineral. abh., 157, 363–380. haas, j. & péró, c. (2004): mesozoic evolution of the tisza megaunit.– int. j. earth sci. (geol. rundsch.), 93, 297–313. hunt (1995): petroleum geochemistry and geology.– w.h. freeman and company, new york. jamičić, d. (1983): strukturni sklop metamorfnih stijena krndije i južnih padina papuka [structural fabric of the metamorphosed rocks of mt. krndija and the eastern part of mt. papuk – in croatian].– geol. vjesnik, 36, 51–72. jamičić, d. (1988): strukturni sklop slavonskih planina (sjeverni psunj, papuk, krndija) [structural fabric of the slavonian mts. (northern psunj, papuk, krndija) – in croatian]. unpubl. phd thesis, university of zagreb, 152 p. jamičić, d. (1989): osnovna geološka karta sfrj 1:100000, list daruvar [basic geological map of sfry 1:100000, daruvar sheet – in croatian] – geol. inst. zagreb, fed. geol. inst. beograd. jamičić, d. (1995): the role of sinistral strike-slip faults in the formation of the structural fabric of the slavonian mts. (eastern croatia).– geol. croat., 48, 155–160. jamičić, d. & brkić, m. (1987): osnovna geološka karta sfrj 1:100000, list orahovica [basic geological map of sfry 1:100000, orahovica sheet – in croatian].– geol. inst. zagreb, fed. geol. inst. beograd. jamičić, d., brkić, m., crnko, j. & vragović, m. (1987): osnovna geološka karta sfrj 1:100000. tumač za list orahovica [basic geological map of sfry 1:100000, geology of the orahovica sheet − in croatian].– geol. zavod, zagreb, sav. geol. zavod, beograd, 72 p. jerinić, g., pamić, j., sremec, j. & španić, d. (1994): first palinological and organic-petrographic dana on very low and lowgrade metamorphic rocks in slavonian mt. (north croatia).– geol. croat., 47, 149–155. judik k., árkai, p. horváth, p., dobosi, g., tibljaš, d., balen, d., tomljenović, b. & †pamić, j. (2004): diagenesis and low-temperature metamorphism of mt. medvednica, croatia: mineral assemblages and phyllosilicate characteristics.– acta geol. hung., 47/2–3, 151–176. judik k., balogh, k., tibljaš, d. & árkai, p. (2006): new age data on the low-temperature regional metamorphism of mt. medvednica (croatia).– acta geol. hung., 49/3, 207–221. kisch, h.j. (1990): calibration of the anchizone: a critical comparison of illite “crystallinity” scales used for defi nition.– j. metamorph. geol., 8, 31–46. kisch, h.j. (1991): illite “crystalinity”: recommendations on sample preparation, x-ray diffraction settings, and interlaboratory samples.– j. metamorph. geol., 9, 665–670. kisch, h.j., árkai, p. & brime, c. (2004): on the calibration of the illite kübler index (illite “crystallinity”).– schweiz. mineral. petrogr. mitt., 84, 323–331. kretz, r. (1983): symbols for rock-forming minerals.– am. mineral., 68, 277–279. kübler, b. (1964): les argiles, indicateurs de métamorphisme.– rev. inst. franc. pétrol., 19, 1093–1112. kübler, b. (1967): anchimetamorphisme et schistosite.– bull. centre rech. pau snpa 1, 269 – 278. kübler, b. (1968): evaluation quantitative du métamorphisme par la cristallinité de i’illite.– bull. centre rech. pau snpa 2, 385–397. kübler, b. (1984): les indicateurs des transformations physiques et chimiques dans la diagenèse, température et calorimétrie. in: “thermométrie et barométrie géologiques”, lagache, m. ed. soc. fr. minéral. cristallogr., paris, 489–596. geologia croatica geologia croatica 62/1 72 kübler b. (1990): “cristalinité” de i’illite et mixed-layers: breve revision.– schweiz. mineral. petrogr. mitt., 70, 89–93. kübler, b. & jaboyedoff, m. (2000): illite crystallinity, compte rendu de l’académie des sciences, paris.– earth planet. sci., 75– 89. pamić, j. (1986): magmatic and metamorphic complexes of the adjoining area of the northernmost dinarides and pannonian mass.– acta geol. hung., 29, 203–220. pamić, j. (1998): crystalline basement of the south pannonian basin based on surface and subsurface data.– nafta, zagreb, 49, 371– 390. pamić, j. & jamičić, d. (1986): metabasic intrusive rocks from the paleozoic radlovac complex of mt. papuk in slavonija (northern croatia).– rad jazu, zagreb, 424, 97–125. pamić, j. & lanphere, m. (1991): hercynian granites and metamorphic rocks of the mts. papuk, psunj, krndija and surrounding basement of the pannonian basin, north croatia (in croatian).– geologija, ljubljana, 34, 81–235. pamić, j., lanphere, m. & belak, m. (1996): hercynian i–type and s–type granitoids from the slavonian mountains (southern pannonian, north croatia).– n. jb. mineral. abh., 171, 155–186. pamić, j. & jurković, i. (2002): paleozoic tectonostratigraphic units of the northwest and central dinarides and the adjoining south tisia.– int. j. earth sci., 91, 538–554. pamić, j., balen, d. & tibljaš, d. (2002): petrology and geochemistry of orthoamphibolites from the variscan metamorphic sequences of the south tisia in croatia-an overview with geodynamic implications.– int. j. earth sci., 91, 787–798. potel, s., ferreiro mählmann, r., stern, w.b., mullis, j & frey, m. (2006): very low-grade metamorphic evolution of pelitic rocks under high pressure/low temperature conditions, nw caledonia (sw pacifi c).– j. petrol., 47, 991–1015. rieder, m., cavazzini, g., d’yakonov, y., frank-ka menetskii, v., gottardi, g., guggenheim, s., koval, p., müller, g., neiva, a., radoslovich, e., robert, j.l., sassi, f.p., takeda, h., weiss, z. & wones, d. (1998): nomenclature of the micas.– clay. clay. miner., 46, 586–595. sassi, f.p. (1972): the petrological and geological signifi cance of the b values of potassic white micas in low-grade metamorphic rocks. an implication to the eastern alps. tschermaks.– mineral. petrogr. mitt., 18, 105–113. sassi, f. & scolari, a. (1974): the b value of the potassic white micas as a barometric indicator in low-grade metamorphism of pelitic schists.– contr. mineral. petrol., 45, 143–152. slovenec, d. (1986): nalazi pirofi lita, paragonita, margarita i glaukonita u stijenama slavonskih planina.– geol. vjesnik, zagreb, 39, 61–74. stampfli, g.m., borel, g.d., marchant, r. & mosar, j. (2002): western alps geological constraints on western tethyan reconstructions.– j. virt. explorer, 8, 77–106. warr, l. & rice, h. (1994): interlaboratory standardization and calibration of clay mineral crystallinity and crystallite size data.– j. metamorph. geol., 12, 141–152. wang, h., frey, m. & stern, w.b. (1996): diagenesis and metamorphism of clay minerals in the helvetic alps of eastern switzerland.– clay. clay. miner., 44, 96–11. manuscript received april 16, 2008 revised manuscript accepted october, 9, 2008 1. introduction the frequency of earthquake occurrence and concentrations of their foci enable definition of the spatial position of seismotectonic zones. these zones are formed by the opposing displacement of relatively large rock masses and mark the area of the most extensive deformations of structural fabric. in this manner, they directly depict the principal characteristics of structural relations at depth. six cross-sections are constructed in order to illustrate the separate zones and conditions of their formation, and also to correlate their strike and spatial position with the most important faults of the regional structural fabric of the dinarides (fig. 1). seismotectonically active zones in the dinarides vlado kuk 1, eduard prelogovi∆ 2 and ivan dragi»evi∆ 2 the importance of the studied zones becomes observable upon correlation with the known basic structural classifications (e.g. herak, 1986, 1991; bla©kovi∆, 1990) and especially with the analyses of the possible structural relations at depth (e.g. miljush, 1973; zagorac, 1975; biju-duval, 1977; cvijanovi∆ et al., 1979; aljinovi∆, 1984; bla©kovi∆, 1998). a more complete insight to the relations at depth is enabled by the seismic sections and some of the identified marker horizons (skoko et al., 1987; aljinovi∆ et al., 1990; tari-kova»i∆ & mrinjek, 1994; lawrence et al., 1995; prelogovi∆ et al., 1995; grandi∆ et al., 1997). it is after the data from the earthquake catalogues were included in correlation (karnik, 1971; herak et al., 1996), that it became possible to single out the separate seismotectonically active zones at depth (aljinovi∆ et al., 1984, 1987; del ben et al., 1991; marku©i∆ et al., 1998; prelogovi∆ et al., 1995). with analyses of the stress regime and the possible deformations of the structural fabric (e.g. anderson & jackson, 1987; herak et al., 1995; prelogovi∆ et al., 1999; altiner, 1999) additional data were acquired, necessary for a more detailed explanation of the presence and characteristics of the studied zones. 2. seismicity from their seismic potential, the dinarides are the most remarkable area of croatia. this is especially true for the se part, where earthquakes are the most frequent and also the strongest. this statement is based not only on the measurements of recent seismic activity, but also on the historic data sources showing that around 20 earthquakes with an epicentre intensity of ix° mcs or more, occurred for example in the dubrovnik area and on the montenegro coast. the most reliable and detailed data pertain to the dubrovnik earthquake of 1667, that had epicentre intensity of x° mcs. the strongest earthquake of modern times, happened in 1979 in the montenegro coastline area. the following parameters were recorded: magnitude m=7.2, focal depth h=14 km and epicentre intensity i=ix-x° mcs. strong earthquakes also occurred in the ston area, nw of dubrovnik. in 1850 one occurred with and epicentre intensity of viii° mcs. there was another strong g eol . c roat. 53/2 295 303 7 figs. zagreb 2000 key words: recent tectonic movements, earthquake foci concentrations, structural relations at depth, dinarides, croatia. 1 university of zagreb, faculty of sciences, department of geophysics, horvatovac b.b., hr-10000 zagreb, croatia. 2 university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, hr-10000 zagreb, croatia. abstract seismotectonically active zones are formed due to displacements of segments of the adriatic micro-plate that differ in size and in their rate of movement, and by the resistance of the rock masses of the dinarides. the spatial position of these zones can be determined through the locations of earthquake foci. the zones of seismotectonic activity are then correlated with the most important faults on the surface. the seismotectonically active zones are relatively steeply inclined in the shallowest 10-20 km, which is caused by the oblique contacts between the adriatic micro-plate and the dinarides. the zones are curved at depth in many cases, which reflects the compression of the area. curved parts of the zones are characterised by the greatest pressures and also by the most frequent earthquakes. mildly inclined zones reflect the reverse displacements in the area, also probably the activity on contacts between rock masses of different density, or the extension of the adriatic micro-plate subduction. the southern part of the plate is the most active. the greatest pressures caused by these movements occur in the area between mljet island and dubrovnik. therefore the majority of earthquakes, and notably the strongest ones, occur in the area between split, imotski, hvar island and dubrovnik, as well as along the montenegro coast in a se direction. 296 geologia croatica 53/2 earthquake in 1996 which had m= 6.0, h=13 km and i=viii-ix° mcs. in the area ne of ston, a 1927 earthquake is mentioned with m=6.0, h=17 km and i=viii° mcs. the area around the neretva river valley is also characterised by marked seismic activity. there are historic records of several earthquakes with i= viii° mcs. undoubtedly the most important, although unreliable, is the record of an earthquake that happened in 1479 with i= ix° mcs. the two strongest earthquakes in mt. biokovo occurred in january 1962. the first one had a magnitude of 5.9 (i=viii° mcs), and a second one magnitude of 6.1 (h= 10 km, i= viii-ix° mcs). among stronger earthquakes is also one in 1884 in mt. mosor, which had epicentre intensity of vii° mcs. the area between the imotski, mt. dinara and west of this mountain is also marked by strong seismic activity. two stronger earthquakes occurred there with an epicentre intensity i=ix° mcs. the first one occurred ne of split in 1898 and the second one near imotski in 1942 (m=6.0, h=7 km). there was also an important earthquake from 1923 with an epicentre in the vicinity of imotski (i=viii-ix° mcs). several other earthquakes with epicentre intensity in the vii-viii° mcs range deserve to be mentioned: 1970 (m= 5.6, h=1 4 km) with epicentre in mt. promina, 1986 (m=5.5, h=8 km) near knin, 1989 (m=5.0, h=9 km) with epicentre in mt. dinara, and the two earthquakes (m=5.6 and 5.5, h=8 and 9 km) that happened in 14 minutes in 1990 in the mt. dinara area. recent seismic activity is less expressed in the coastal area nw of split. there are the historic records of destructive earthquakes in 1418 and 1496, that occurred in the area between split and ©ibenik and west of ©ibenik. there are also records of earthquake damage in the town of zadar on a number of occasions between the 12th and 19th centuries, but the data are not complete enough to enable a more precise definition of the earthquake characteristics. the more reliable data pertain to the two earthquakes in the zadar area (in 1280 and 1300) that had intensity of viii° mcs. of the more recent data, there is the earthquake that happened in 1949 in the mt. velebit channel, with a magnitude of 5.3 and an epicentre intensity of vii° mcs. there are reliable records of several stronger earthquakes in the adriatic off-shore: in 1923 there was an earthquake of magnitude 5.3 (h=15 km) near ©ibenik; in 1934 a magnitude 5.6 (h=30 km) in the off-shore area with the epicentre at 44°n, 14°e; in 1963 there was an earthquake of a magnitude 5.1 (h= 30 km) near the dugi otok island. the disastrous earthquake of the year 361 is supposed to have had occurred in the same area (44°n, 14°e) as the earthquake in 1934. in the inner part of mt. velebit, the earthquake that occurred in 1959 needs to be mentioned. it had a magnitude of 4.6 and an epicentre intensity of vii° mcs (h=20 km). the seismically relatively quieter area of mt. velebit is an extension of the active area that strikes from the northern parts of mt. velebit over rijeka in direction of slovenia. there are historical records of a number of very strong earthquakes in the vicinity of rijeka (in 1721 and 1750) and senj (in 1648, 1873 and 1878) which had intensities of between the viii and ix° mcs, but these data are not reliable. according to some sources (e.g. karnik, 1971) the earthquake that occurred in 1802 near ilirska bistrica had a maximal intensity of viii° mcs. the most important earthquake in this century was in 1916. it had a magnitude of 5.8, focal depth of 18 km and epicentre intensity of viii° fig. 1 location of cross-sections. legend: the most important faults on the surface: 1) southern boundary fault of the pannonian basin; 2) » r n o m e lj -slunj fault; 3) ilirska bistrica r i j e ka senj fault; 4) trieste -u ë ka loπinj fault; 5) velebit fault; 6) dugi otok fault; 7) zadar fault; 8) mosor -biokovo fault; 9) trilj t i h a l j i na »apljina fault; 10) imotski -m e  u g o r je popovo polje fault; 11) ploëe d u b r o v n ik b a r fault. mcs. the latest most pronounced seismic activity was recorded in 1986, with the strongest earthquake of m=4.7, h=9 km and i=vi-vii° mcs. 3. earthquake foci concentrations and the most active fault sections the given cross-sections are positioned in such a way as to show major earthquake concentrations and the most important structural units. the adriatic microplate and the fact that it is fragmented are crucial in the search for reasons for the occurrence of the seismotectonically active zones (skoko et al., 1987; aljinovi∆ et al., 1987). two larger parts of the plate exist one in the northern adriatic and italy, and another in the southern adriatic. there is also a smaller section in between that lies in the approximate adriatic centre. a consequence of the micro-plate fragmentation is the various rates and directions of displacement of its parts. the spatial position of the seismotectonically active zones is conditioned by the distribution of different rock masses, and by their size and position within the dinarides. these masses provide direct resistance to the adriatic micro-plate movements. 3.1. cross-section a-b, cres island karlovac (fig. 2) in this cross-section, the marked zone of seismic activity is shown, that strikes from the northern mt. velebit over rijeka in direction of neighbouring slovenia. the largest earthquake concentration is in the area that dips at an angle of 60°, and is 30 km wide. earthquakes in this zone occur at depths down to 20 km. distribution of the earthquake foci clearly depicts two smaller zones that are correlated with the faults on the krk island and with the ilirska bistrica r i j e ka s e n j fault. the second zone strikes along the border of dinaricum and reaches a maximal thickness of 10 km. the characteristic feature of this zone is the steep inclination down to the depth of 10 km, a curved part between the 10 and 14 km depth, and the relatively mild dip down to 24 km, where it reaches the area under mrkopalj and vrbovsko. there is another gently dipping zone that lies between the 20 and 30 km and results from the activity of the deeper parts of the earth’s crust. the contacts between the dinaricum and the supradinaricum, and the pannonian basin as well, are also marked by seismotectonic activity. the foci concentrations in the steeply dipping zones that reach depths of 15 and 20 km are observed, but with occurrence of earthquakes at maximum depths of 30 km. the steeply inclined contours of the area with the largest concentration of earthquake foci depict the compression of the dinarides and the oblique subduction of the adriatic micro-plate in respect to the orientation of the structural units. the increased gravimetric gradients depict the step-like displacements of the rock masses in the subsurface. looking at the cross-section, this means more significant subduction of the adriatic micro-plate. displacements of the relatively large masses influence the spatial bending of the seismotectonic zones. the greatest pressures are formed in the curved parts of the zones, where the majority of the earthquakes also occur. in addition, it is noted that the zones are spatially bent almost into the horizontal position, which marks the reverse displacements and activity of the contacts between the rock masses of different density. 297kuk, prelogoviê & dragiëeviê: seismotectonically active zones in the dinarides fig. 2 seismotectonic cross-section a-b, cres island karlovac. legend: 1) seismotectonically active zones; 2) earthquake epicentres with magnitudes: a) <4, b) 4-5, c) >5; 3) faults; 4) inferred contact between the carbonates and underlying rocks; 5) zones of higher gravimetric gradients; 6) direction of displacement of the adriatic microplate. 298 geologia croatica 53/2 3.2. cross-section c-d, lo©inj island mt. kapela (fig. 3) concentration of the earthquake foci is particularly observable in this section. the zone dips at 55-60°, has a width of 20 km, and the earthquake foci are located at depths down to 34 km. the foci locations enable separation of the seismotectonically active zones that are correlated with the velebit fault and some of the faults that strike parallel to the islands. the position of the area with the greatest concentration of earthquakes clearly illustrates the oblique contact between the adriatic micro-plate and the dinarides. 3.3. cross-section e-f, dugi otok island zadar -mt. velebit (fig. 4) the seismotectonically active zones are singled out along the section and correlated with faults on the surface. the first one is the zone connected to the velebit fault. it dips at 55°, has a width of 10 km, and is marked by earthquakes to a depth of 13 km. the relatively narrow zones with a dip range of 20-30° are correlated with the dugi otok fault and the zadar fault. the spatial position of these zones depicts the reverse/overthrust relations and displacements of the structural units. the strongest earthquakes occurred outside of these zones at depths of 20 to 30 km. they are probably connected with the faults that reach the surface in the middle of the adriatic sea bottom, or otherwise reflect recent deformations of the relatively deeper parts of the earth’s crust. 3.4. cross-section g-h, ©olta island split mt. dinara (fig. 5) the largest concentrations of earthquake foci are located in the mosor biokovo fault zone, or along its branching faults that partly strike along mt. dinara. a major zone of seismotectonic activity is steeply inclined at depths less than 7 km, and then acquires a dip of 25° in order to reach the maximum depth of 20 km under mt. dinara. the zone is 6 to 8 km wide and obviously a curved one. the curved section in the depth range of 13 to 20 km is marked by foci of the strongest earthquakes recorded so far. the 15 km wide area of the largest earthquake concentration is connected with the branching faults of the main zone and dips at an angle of 5565°. a deeply situated zone of seismotectonic activity that has a mild inclination (of 25°) and particular concentration of earthquakes in the depth range of 20 to 32 km is very interesting. it is probably connected with the faults around ©olta island and is spatially parallel to the main zone of the mosor biokovo fault. in both of the observed zones there is a more prominent concentration of the earthquake foci in the section that has a dip angle of approximately 25° some 30-40 km in length. this points to the possible position and activity of the contacts between the rock complexes of different density. it is also observed that some of the earthquake foci concentration zones are spatially located very close to each other, or are even overlapping. this indicates a significant compression of the area. fig. 3 seismotectonic cross-section c-d, loπinj island mt. kapela. legend: 1) seismotectonically active zones; 2) earthquake epicentres with magnitudes: a) <4, b) 4-5, c) >5; 3) faults; 4) inferred contact between the carbonates and underlying rocks; 5) zones of higher gravimetric gradients; 6) direction of displacement of the adriatic microplate. 299kuk, prelogoviê & dragiëeviê: seismotectonically active zones in the dinarides 3.5. cross-section i-j, hvar island mt. biokovoimotsko polje (fig. 6) the greatest concentrations of earthquake foci encompass the hinterland of mt. biokovo. the seismotectonically active zone connected to the mosor biokovo fault zone is very pronounced. the spatial position of the zone is the most important: a steeply inclined part dips at 60° in the first 10 km, a curved section between 10 and 16 km, and a mild inclination of 20° from 16-22 km which influenced a large extent to the imotsko polje. the zone is up to 5 km wide. the strongest earthquakes occurred in the curved section of the zone. there is also a branch of this zone that is characterised by seismotectonic activity, where earthquake foci depict an inclination of 60°. the concentration of earthquakes is observable in the almost vertical zone in the imotsko polje area. this zone is around 8 km wide with earthquake foci at depths between 2 and 14 km. the relatively higher activity of the adriaticum area also exists, and the active zones are correlated with the faults near the middle dalmatian islands. they are situated above the basement of the carbonate rock complex, but there are also the two zones that lie below this contact. they illustrate the deformations or displacements at the 16 to 30 km depth range, probably along the contacts between rock complexes of different density. the following observations are the most important: stacking of a number of seismotectonic zones at various depths implies the greater activity of the area; mildly inclined zones, and especially the length of the 30 km of the zone correlated with the mosor biokovo fault depict the reverse-overthrust displacements; the strongly expressed bending of the zone correlated with the mosor biokovo fault, formation of the branching fault and the vertical faults around the imotsko polje point out to the possibility of rotation of structural units, and to the oblique spatial movements in respect of their strike, as well as to the horizontal displacement on the vertical faults. 3.6. cross-section k-l, adriatic off-shoremljet island ston (fig. 7) the largest concentration of earthquake foci is in an area 20-30 km wide and has a variable dip angle of 30°60°. earthquakes occur there at depths less than 30 km. the earthquake foci concentrations depict the strongest activity in the zone that is associated with the ploëe d u b r o v n ik bar fault, but there are also some active faults within the adriaticum unit (fig. 7). particularly increased activity is observed along the adriaticum dinaricum contact, in the fault zones parallel to mljet island and the peljeπac peninsula. the locations of fig. 4 seismotectonic cross-section e-f, dugi otok island z a d ar mt. velebit. legend: 1) seismotectonically active zones; 2) earthquake epicentres with magnitudes: a) <4, b) 4-5, c) >5; 3) faults; 4) inferred contact between the carbonates and underlying rocks. 300 geologia croatica 53/2 fig. 5 seismotectonic cross-section g-h, ©olta island s p l it mt. dinara. legend: 1) seismotectonically active zones; 2) earthquake epicentres with magnitudes: a) <4, b) 4-5, c) >5; 3) faults; 4) zones of higher gravimetric gradients. fig. 6 seismotectonic cross-section i-j, hvar island mt. biokovo imotsko polje. legend: 1) seismotectonically active zones; 2) earthquake epicentres with magnitudes: a) <4, b) 4-5, c) >5; 3) faults; 4) inferred contact between the carbonates and underlying rocks; 5) zones of higher gravimetric gradients. 301kuk, prelogoviê & dragiëeviê: seismotectonically active zones in the dinarides earthquake foci show that this is actually a single area of seismic activity, which means that there is extensive compression in this area. what also has to be emphasised is the significant subduction of the adriatic micro-plate, that reaches 40 km inland from the coastline. as a consequence, there is activity of the carbonate complex basement and the reverse-overthrust displacements on the faults within the adriaticum, together with formation of a broad active zone marked by deformations of structural fabric and the permanent occurrence of earthquakes. the last significant earthquake occurred near ston in 1996. it had a magnitude of 6.0. focus of the main earthquake and of the subsequent ones are shown in fig. 6b (marku©i∆ et al., 1998). the spatial concentration of earthquakes in the area of the above described zone of seismotectonic activity is discerned. numerous earthquake foci enable the more detailed separation of minor zones connected with some of the faults. 4. conclusion the adriatic micro-plate movements and the resistance of the dinarides are of key importance in tectonic movements. two facts are vital for the formation of the seismotectonically active zones that are curved at depth: three sections of the micro-plate exist, differing in size and in their rate of movement; there are major rock masses in the dinarides area that resist the micro-plate movements. the differences in appearance of the seismotectonically active zones in the northern, central and the southern part of the study area are illustrated in the cross-sections. this indicates that there are the rock masses that differ in size and orientation. in addition, the microplate movements cause the formation of the stress field that influences deformation and displacement of separate rock masses and the seismotectonic activity. fig. 7 seismotectonic cross-section k-l, adriatic off-shore mljet island ston. legend: 1) seismotectonically active zones; 2) earthquake epicentres with magnitudes: a) <4, b) 4-5, c) >5; 3) faults; 4) inferred contact between the carbonates and underlying rocks; 5) zones of higher gravimetric gradients; 6) direction of displacement of the adriatic microplate. 302 geologia croatica 53/2 the area shown in cross-sections a-b and c-d has one significant feature marked compression of the southern alps and the northern dinarides area. due to the almost perpendicular micro-plate movement in respect to the strike of structures, reverse displacements are present. further east, in the area of rijeka, there is oblique subduction of the adriatic micro-plate under the dinarides. the most recent measurements of the regional stress orientation have yielded results in the range between the 20-200° and the 170-350° (altiner, 1999; prelogovi∆ et al., 1999). the faults are markedly characterised by dextral tectonic transport. the relatively steeply inclined zones of seismotectonic activity are formed at depth due to the oblique contact between the adriatic micro-plate and the dinarides. mt. velebit together with its hinterland has an orientation of the principal horizontal stress in the range between 180360° and 160-340°. this is also favourable for displacements of structural units in the se direction. in the cross-section e-f, the seismotectonically active zone associated with the velebit fault is relatively steeply dipping and depicts the spatial oblique displacements of the rock masses. in the same cross-section, the strongest earthquakes occur in the mildly inclined zone that reaches a depth of 30 km. formation of this zone reflects the pressure caused by the southern part of the adriatic micro-plate. the southern part of the micro-plate moves in a nnw direction. the regional stress in the area south of split, within the adriaticum and dinaricum, most commonly has an orientation between the 15-195° and 170350°. this is almost at right angles to the strike of the structural units. compression of the area occurs. data on the ston earthquake of 1996 have demonstrated that the largest pressures were caused by the micro-plate movements in the area between mljet island and dubrovnik. this is confirmed by displacements of the parts of structural units close to the surface, for instance: near split in part of mt. biokovo, on the hvar and korëula islands in the s-sw direction, inside mt. biokovo and in its hinterland, as well as in the surroundings of dubrovnik to the s-se. significant subduction of the adriatic micro-plate is illustrated in these cross-sections, particularly in section k-l. the g-h and i-j cross-sections also depict the mildly inclined zones of seismotectonic activity. these zones reflect the reverse-overthrust displacements in the area, and also probably the activity of the contacts between rock complexes of different density. the steeply dipping seismotectonic zones are interpreted in terms of the oblique spatial displacements of rock masses, while in the imotsko polje area horizontal displacements of tectonic blocks occur. 5. references altiner, y. (1999): analytical surface deformation theory for detection of the earth’s crust movements.springer verlag, berlin, heidelberg, new york, 100 p. aljinovi∆, b. (1984): najdublji seizmiëki horizonti ne jadrana (the deepest seismic horizons in the northern adriatic).unpublished ph.d. thesis, university of zagreb, 264 p. aljinovi∆, b., bla©kovi∆, i., cvijanovi∆, d., prelogovi∆, e., skoko, d. & b r d a r e v i ∆ , n . (1984): correlation of geophysical, geological and seizmological data in the coastal part of yugoslavia.bolletino di oceanologia teoretica ed applicata, ii/2, 77-90, trieste. aljinovi∆, b., prelogovi∆, e. & skoko, d. (1987): novi podaci o dubinskoj geoloπkoj grai i seizmotektonski aktivnim zonama u jugoslaviji (new data on deep geological structure and seismotectonic active zones in region of yugoslavia).geol. vjesnik, 40, 225-263. aljinovi∆, b., prelogovi∆, e. & skoko, d. (1990): tectonic processes on the contact of the adriatic platform and the dinarides in the area of the northern dalmatia.proc. of the inter. conf. on mechanics of jointed and faulted rock, inst. of mech/tech. univ. of vienna, 179-182, a.a. balkema, rotterdam/brookfield. anderson, h. & jackson, j. (1987): active tectonics of the adriatic region.geophys. j.r. astr. soc., 91, 937-983. biju-duval, b. & montader, l. (eds., 1977): geological evolution from the tethys to the mediterranean from the mesozoic to present.inter. symp of the structural hist. of the mediterranean basins, split 25-29 oct. 1976, technip, 13-18, paris. bla©kovi∆, i. (1990): nova globalna tektonika i primjena koncepcije u podruëju jadranskog mora (new global tectonics and application of the conception in the area of adriatic sea).pomorski zbornik, 28, 555-587, rijeka. bla©kovi∆, i. (1998): the two stages of structural formation of the coastal belt of the external dinarides.geol. croatica, 51/1, 75-89. cvijanovi∆, d., prelogovi∆, e., kranjec, v., skoko, d., zagorac, æ., bahun, s. & olui∆, m. (1979): seizmotektonska karta hrvatske (seismotectonic map of croatia).unpublished map, university of zagreb, faculty of sciences, department of geophysics, zagreb. del ben a., finetti, i., rebez, a. & slejko, d. (1991): seismicity and seismotectonics at the alps303kuk, prelogoviê & dragiëeviê: seismotectonically active zones in the dinarides dinarides contact.bull. di geophis., xxxiii/130131, 155-176, trieste. grandi∆, s., boromisa-bala©, e. & ©u©ter»i∆, m. (1997): exploration concept and characteristic of the dinarides stratigraphic and structural model in the croatian offshore area.nafta, 4, 117128, zagreb. herak, mi. (1986): a new concept of geotectonics of the dinarides.acta geologica, 16/1, 1-42, zagreb. herak, mi. (1991): dinarides. mobilistic view of the genesis and structure.acta geologica, 21/2, 35117, zagreb. herak, ma., herak, d. & marku©i∆, s. (1995): fault-plane solution for earthquakes (1956-1995) in croatia and neighbouring regions.geofizika, 12, 43-56, zagreb. herak, ma., herak, d. & marku©i∆, s. (1996): revision of the earthquake catalogue and seismicity of croatia.terra nova, 8, 86-94. karnik, v. (1971): seismicity of the european area.part i, 1-364, part ii, 1-218, czech ac.sc., praha. lawrence, s.r., tari-kova»i∆, v. & gjuki∆, b. (1995): geological evolution model of the dinarides.nafta, 46/2, 103-113, zagreb. marku©i∆, s., herak, d., ivan»i∆, i., savi∆, i., herak ma. & prelogovi∆, e. (1998): seismicity of croatia in the period 1993-1996 and the ston-slano earthquake of 1996.geofizika, 15, 83101, zagreb. miljush, p. (1973): geologic-tectonic structure and evolution of outer dinarides and adriatic area.bull. am. assoc. petrol. geol., 57/5, 913-929. prelogovi∆, e., aljinovi∆, b. & bahun, s. (1995): new data on structural relationships in the north dalmatian area.geol. croatica, 48/2, 167/176. prelogovi∆, e., kuk, v., buljan, r., tomljenovi∆, b. & skoko, d. (1999): recent tectonic movements and earthquakes in croatia.proc. geodynamics of the alpe-adria area by means of terrestrial and satellite methods, 255-262, zagrebgraz. skoko, d., prelogovi∆, e. & aljinovi∆, b. (1987): geological structure of the earth’s crust above the moho discontinuity in yugoslavia.geophys. j.r.a.s., 89, 379-382. tari-kova»i∆, v. & mrinjek, e. (1994): the role of paleogene clastics in the tectonic interpretation of northern dalmatia.geol. croatica, 47/1, 127-138. zagorac, æ. (1975): neki rezultati magnetometrije u sklopu kompleksne geofiziëke interpretacije podruëja dinarida (some results of magnetometry in sense of complex interpretation of dinarides).nafta, 2, 61-64, zagreb. manuscript received january 10, 2000. revised manuscript accepted november 13, 2000. 304 geologia croatica 53/2 geol. c roat. 49/2 197 2021 9 figs. 1 1 1 zagrei3 1996 revie\v paper prospecting for bypassed oil and gas zaki bassiouni ' and josipa velie ' key words: prospecting, bypassed oil , bypassed gas. abstract in recent years, il has been increasing ly difficult to economicall y explore for hydrocarbons because of geopoliti cal unce rt aint ies and low oil pricc~ . in many countri es the remaining po tential prospects me in areas which arc difricul\ to access becau se of cli mate, terrain , offshore water depth . and/or envi ronmenta l const rai nts. al so, most of the relat ively simple geologic basins have been ex ploited leaving to explore areas o f complex geology. in addit ion. ihe probabil ity of find­ ing large fields in mature basins is understandably low. 1\ is known that substantia l amounts of hydrocarbo ns has been bypassed on a macroscopic and microsco pi c sca le in know n fiel ds. thi s is mainl y due to reservoir heterogeneiti es and complex lithology which rcsult in poor rcscrvo ir characterisation. innovative reservoir managcment op ti ons can rcduce the amount of bypassed hydrocar­ bons. emerging tec hn o logies such as 3-d seismic and hori zon tal wells facilitate the locmion o f oil and gas which has been bypassed at near-v irgin saturat ion. s uffi cient ly large amou nt s of such hydrocar­ bo ns co uld be economi c <l li y produced in the ncar term by infi ll drilling. innovati ve improved oi l recovery method s can revive reser­ voirs which were considered depl eted by co nventi onal standard s. these emergi ng tec hn olog ies and method s have the potential of adding bypasscd o il to thc reserv cs cat egory at a cost per barrel much lower than the cost of ncw discoveries. j. introduction the 10lal wo rl d o il and gas resource is classi fi ed , according to the degree of geologic assurance, as poten­ tially recoverable discovered, and undiscovered. part of the di scovered resources have already been produced. the distributi on of the uliimate resource bel ween these categories diller from country to country. for the unit­ ed stales, a mature oil and gas producer, half of the ul ti­ mate resource have been produced. future producti on wi ii come from a va ri ety of sources. reserves in cur­ rent ly proved fields, plus the growth of these fi elds will colllribwe half of futurc production. the other half will come primaril y from currently und iscovered resources. proceedings kljucne rijeci: ist raz ivanje, preoslala nafta, preostali plin. sazetak isplativo is trazivanj e ugljikovodika odlledavllo je opccnilo posta10 otciano bilo zbog gcopoli ti c kih oko lnos li bilo zbog ni ske cije ne nafl e. u mll ogim zemljama pronalazc nje preos talih kolici na nafle i pli nl! c ine za mrsc nim nepris tupacnosl lerena, surova klim'l. vel ik e dubinc mora i/il i bojazan ad oneciscenja okoli5a. brojni bazeni. geo­ loski rclalivno jednoslavni i privid no iscrpljeni , sigmno imaj u dijelo­ va sl ozenijc gradc i saslava koj i bi se mogli dodalno islraziv ati. no, vjerojatnost pronalazenja vej ikih polja u nj imaje svakako mal a. znano je da .'i u s tanovite kolicine ug ljikovodika prcostal e u poz­ natirn poljim<l kako u makroskopskim taka i ii mikroskopsk im razl11jcrima, sto llglavnorn nvisi 0 s loicllo sti grade i titolo skog sas tav a lciisl<l, odnos nn 0 losijim rczc rvoarskirn znacajkama. novi poslupc i gospodarenja lez islima smalljuju ko lieinl! preos tal c naft c. nastupa­ juce tchnologijc kao s to su 3-d sc izmik a i vodoravno buiicnjc o mogucavaj u smjestavanje nafle i phna koja preostaje u go to\,o is ko nskoill zasice njll. dna bi sc rnogla pro izvoditi ii gos podarski isplativim kolici nama kao sio se 10 posli ze i primjericc uli skivanjem u buso tine. suv remcni. savrscniji !lacini o tkri vanja nafl e i plinu mogu lic inil i vr lo zilll irnlji vi mil i ona tci. is ta koja se prema l1obi cajeni111 mj erilirn a s rnatraju isc rplj cni mu. na osnov i rez ultala spo mcllutih novih lc l1l10 logija i meloda preos tala bi sc nana 1110gla uk ljuciti u pri ­ dobivc za lihe po cijcni ni ioj od cij ene novootkrivcni h kolicina ug tj ikovod ika . in most mature areas, average inland di scovery is becoming smaller and more difficult to find. deeper prospects presenl a challenge of operaling in hi gh tem­ perat ure and high pressure, o f le n corros ive, e nv iron­ me nl. ex ploring [or undi scovered offshore resources requ ire drilling, completion, and produclion operat ions in deep water. the cost assoc iated wi th offshore envi­ ronment necess itates the discovery o[ larger to large r accumu lations. a fi eld of 4.8 million mj (30 mill ion barrels) may be economi ca ll y viable inlan d but the same discovery in 200 melers waters wou ld show mini­ mal return (cox, 1980). a large percent o[ the world 's undi scovered resou rces lies north of the 60th parallel in arctic cana­ da and russ ia. the cos ts of exp loration , deve lopme nt i louisiana statc un iversity, petrol. engin. dep t. , ceba 3523, baton rouge. la 70803-6417, usa. ~ universi ty o f zagreb, faculty of mining, geology & petroleum engi neering, picroll ijcva 6, p.d.box 186, iir i 0000 zagreb, croatia. 19x cumu lative production 9.94 bbbl (34%) /' proved reserves 1.92 bbbl (6.6%) mobile unrecovered oil 553 bbbl (19%) immobile oil i i 78 bbbl (40.4%) total original oil-in-place = 29.17 billion bareis rig 1 di stribution of origi nal oil-in-place in federal offshore gulr 01" mex ico, aftcr ,111 lcr report ci.cf. , 1996) . and transportation in the arctic arc vcry high. hi ghcr prices wil l be required to support fut1he r exploration for and developme nt o f the arctic reg ion. exploring the arctic and other inhospitable and remoic areas slich as the ra in forest will also require the development of eco­ logically sound tcchnologies. th e world rcso urce base is large ly depen dent on three rac tors: price of o il and gas, cost of ex ploration and development , and availabi lity of lands for explo­ ration. the surface area ye t to be explored is decreasing continllous ly , and the price of oil is determi ned by forces ex ternal to the petroleum industry. the oil indus­ try forecasts appears to be mov ing towards using a fla t o il pr ice. as the resource base continues to mature, the cost req uired to explore for and to develop remai ning resources is in creas ing. new tec hnolog ies will be the key to rcducing the cost. these [actors and considera­ tions are creating a business cl imate that is challenging and wi ll necess itate cons iderable change in pri ori ties, strategies, and management structure. the industry has then to give more consideration to bypassed oil. thi s relatively new term refers to the hydrocarbons whi ch have been bypassed on microscopatile updip potential volume salt profile as mapped fi g. 3 bypasscd oi l due inaccurate detection of salt bo undary. afte r an tcf report ( i.c.f., (996). gcologij cro;liic:l 49f2 "' 031 "l! • cd 0.30 c 029 ~ 026 ~ c 0" 0 u 0.26 0 " 025 0 q: 0.24 i5 0.23 • " 022 0 u 0" 1981 '''''' 1987 1990 '993 year fi g. 2 crude oil produclion ( 1981-1 994) of federal ofrshorc gul f of mexico, aner an icf report ( i. c. f. , 1996). ic and macroscop ic scal e in already discovered and deve loped rese rvoirs. oi l bypassed on mic roscopi c scal e is the immobile oil trapped in the reservo ir pores by viscous and capillary forces and cannot be displaced by water. the immobile oil is the target [or number of enhanced oil recovery techniq ues particularl y mi sc ible gas and chemical fl ood ing. oil bypassed on a macro­ scop ic scale is the mobil e oi l which remain s in th e rese rvoir aft er conventiona l recovery for a varie ty o r reasons. the magn itude or bypassed oij is signifi cant. fo r ex ample, in federal o ffshore gulf o f mex ico it is es timated that at the conclusion of conventi onal recov­ e ry techni ques, nearl y two-third s of the known resources will remain unrecovered . a 878 mi lli on ill j (5.53 billion barrels) or 19% of ooip is in the ealego ry of mobile bypassed oil (pi g. 1). figu re 2 shows that the gu lf of mexico annual offshore produ ction pea ked in 1970 and has since fall en dram atically. the noti ceable increase in prod uct ion start ing in 1990 is primarily due to the application of 3-d seismic, horizonta l wells, and othe r tec hnologies wh ich targeted bypassed oi l. the different types of bypassed oil and the means for their identification and recovery are discussed herea f'ter. fi g. 4 bypassed oi l due to faulling. aft er an tcf report ( i.c.f. , (996) . thc recently developed 3-d seismi c icc hnology can prov ide the necessary infonnalion to prope rly map ihe reservoir. ih~sioulli & velie: prmpec1 ing for bypnssed oil nnd gas all prooucer oilr,m gas injector , currenlowc water $wepl oi l zone ~ ") o;p anglo? fig. 5 schem.hic of [he double di splaccmcnt proccss (after lep$k i ct al. . 1995). 2. bypassed oil due to ina ccu rat e deli­ neation of reservoir boundaries one example or inaccurate delineation or geolog ic structures is ihal or sal t inl rus ion s (fig. 3). optimum selcclioll or drilling locations around sal! intrusions is hampered by refract ion o f the seismic waves as th ey pass through the sa lt body. this refraction tends to dis­ tort the se ismi c images making it d ifficult to pinpoint the salt boundary. much oil has bccn bypassed because ihe sa lt boundaries wcre not clearly visible in seismi c imagi ng. anolher exampl e is tha t of faults which arc not de tected by conventional 2 -d seismic technology (fig. 4). as a res ul! o il in an iso lated fault block is bypassed. 3. bypassed oil due to reservoir heterogeneity oil reservoirs are produced eithe r by natural or arti­ fic ial d ri ve mcc hanism, in whic h oil is pu shed to thc producing wclls by the expanding gas and/or the inva­ s ion or wat e r into the reservoir. the spatial reservo ir he te rogenei ty will leave consi derable volumes or oil bypassed in isolated pockets. if the bypassed pocket is l[lrge enough , it cou ld be produced economically in the near te rm simply by drilli ng a new infi ll we ll withou t the need ror more compl ex and costl y enhanced o il recove ry processes . in a homogeneous system, infill drilling accelera tcs product ion. in a heterogeneous sys­ tcm it al so result s in incremental recovery. the recov­ ery is the result or improved reservoi r con tinuit y, improved arehi and vertical sweep. infill drilling is not without ri sk and requ ires detai led reservoir description to improve chances of success (go uld & sarem , 1989). 199 -coiled lub,ng bypassed 011 pockets fi g. 6 combining ad vanced drilling tcchnologies to reach bypassed oi l pockets. artc r peden & t weedie ( 1995). 4. attic oil and oil bypassed in ti-ie water-swept zones attic oi l is th at oi l trapped upclip from the highest well in a rese rvoi r. attic oil is usually limited in sizc to justify drilling new wells. th is bypassed oil is the target o r s ide-iracking or updip gas injection . the updip gas injection process for recovering attic oil can be ex pand­ ed into a double displacement process (oop) to recov­ er the oil bypassed behind the wate r fro n\. the ddp invo lves updi p gas injection into a wate rinvaded oil eol umn in order to prod uce incrementa l o il. the incre­ mellla l oil results from the mobilisa tion or a fraction of ihe residual o il left behind in the water-s wept zone. gravity-stable gas displacement causes ihe i'ormalion of an oil bank wh ich builds up progress ively as il migrates clown the reservoi r towards the producing well s. a sim­ pl ifi ed scheltialic o f a dipping reservo ir subjected to ddp is shown in fi g. 5. increment al oil recovery depends on the amount of gas injected and thc locat ion of a down-dip wells. favorable condit ions may result in the recovery of up to 40% or the initial oilin -place (lepsk i ct 'ii.. 1995). waterllooded reservoirs of loui siana were screened 10 dctemli ne thc potcntial of recoveri ng incremcnlal oil by co2 inject ion. of the 197 waterflooded rese rvoi rs screened, 39 look economically a ttrac ti ve. the potential incrementa l recovery frolll these reservo irs is about 11.3 m ill ion m ' (7 1 million barre ls) (diaz e t ai. , 1996). 5. water coning whenever a well is producing from an oil layer overlaying a water layer, the pressu re grad ien ts illay deform the horizontal water-oil con tact into a cone shape cont act. the cone height above the ho rizonta l 200 , ! , , i b"'f' .. ~ contact depends on the production rate. above a certain critical rate water will enter the well bore. t he water coning phenomenon may cause the oil cut to reach its economic limit prematurely leaving a signiricant amollnt or mobile oil unrecovered. producing at a rate below critical may be uneconomical. a horizonta l s ide track or lateral may present an economic option as a much higher flow rate can be realised without deform­ ing the horizontal conlact. additional well technolo­ gies, namely coil tubing drilling, and under-balanced drilling can be combined with horizontal and lateral drilling to achieve large improvement in hydrocarbon recoveries in such cases (peden & tweedie, 1995) (fig. 6). 6, bypassed oil due to misinterpre­ tation of well logs potential hydrocarbon-bearing formations are iden­ tified from well log data. misinterpretation of these data, due to the comp lexity or the rock-flu id system, may lead to thc bypassing of comple te inte rva ls. such cases arc the target for reinterpretation of original open hole logs using newly established pet rophysical models. cased hole logs, such as the thermal decay time (tdt) and ihe gamma-ray spectrometry tool (gst), can also be uscd to investigate the current ilu id content in old wells. the reinterpreta tion of old logs was oil in 000 t gas in 000 000 t 6000 5000 hydw~f \ j" \ oil -/, ,,--' , , , " , , , /" gas/ " / ,/,,/ 4000 3000 2000 1000 o 1946 1950 1954 1958 1962 1966 1970 1974 1978 1982 1986 1990 fig. 8 ga s and crude oil p rodu ction (in oil equivalent) in the republic ofcroalia (after vlas ic & 13auk, 1994). 3b ~ , geologia eroatiea 49/2 fig. 7 shaded areas indicating possible bypassed oil in a nearly depleted reservoir in louisiana, after bour­ goyne & kimbrell (1994). attempted in a louisiana field near primary depletion (bourgoyne & kimbrell, 1994). several possi­ bilities or bypassed oil were identified and ind icated by the shaded areas on the cross-section of fig. 7. the top sand is thin and shaly and was not tested for hydrocar­ bon production. new interpretation indicated much higher o il saturation than was indicated by initial inter­ pretations . t his thin sand could be a good candidate for horizontal well application. the other two sands were se lective ly completed. pockets of mobi le o il were bypassed due to uneven advance or watcr and/or absence of perforations. some of these pockets could be the target of infill drilling and/or rccomp letion of old wells. 7. bypassed oil potential in the republic of croa tia oi l and gas prociuction supplies more than half the energy need of the republic of croatia. all present oil and gas production collles from the pannonian bas in. as of 1994, the croatian part of the pannonian basin has produced 78 million tons of oil and 30 billion m3 of gas (ylasic & bauk, 1994). prod uc lion his tory is shown in r ig. 8. t he sharp drop in oil production in the latc eigh ti es is due to occupation of fields in eastern s lavon ia, and reduction of ex ploration act ivities. to remedy this critical situation ina is considering more aggressive exploration policy wh ich will open domestic areas for foreign companies. this option is limited by the relatively small area available for exploration. ina is also considering acquisition of discovcred reserves abroad especia lly in the mediterranean area, and the application of enhanced oil recovery processes (ylasic & bauk, j994). in addition to the above mentioncd options, reserves could also be increased by prospecting lor bypassed oil. the po tential of th is option can not rea listically be de termined before a detailed study is undertaken. the croatian part of the pannonian basin contains s4 reser­ voirs. the eight largest of these fields account for 83% of total recoverable reserves. prospecting for bypassed oi l should target this manageable number of reservoirs. awaiting such a study, we can point to fcw possibil­ it ies. analysing primary recovery indicated that an inef­ ficient solution gas drive was predominant in 1110st of the fields. only few fie lds, with 27% of initial recovcrbassiouili & velie: prospect ing fo r bypassed oil and gas 6 7 -1000 pi : · 1500 m' , m' 0 '000 m; m, ,2 -2500 pi c=j oil ~=~=~=~~ water [i] impermeable rock able rese rves are producing under cflicient water drive. to increase the sweep e fficiency of the encroaching water the presen t spaci ng design of production and injcction wclls cou ld be modified by infi ll drill ing of verti cal or horizontal wclls . innovative improvcd oil recovery me thods such as the double displacement process may also contribute to the recovery of bypassed oil in the watered-out zones. even an average increase or 20% in the ultimate recovery from these reservoirs will result in abo ut 7% increase in the ultimate recovery of croatia. another possibility of the existence of bypassed oil is in reservo ir like the obod reservoir. as shown in fig. 9, oil ex ists in zones with secondary porosity embedded in an impermeable rock (turajlic er ai., 1979), the characterisatio n and delineat ion of reservoirs in such environment is rather difficult . the applicat ion of new technologies such as 3-d seismics coupled with improvements in formation evaluat ion could enhance the geologic picture provided by the lower resolution 2d seism ic surveys. an improved picture should result in additional recovery. the most important gas fields in croatia are molve, kalin avac, and stari gradac (horvat, 1995), the remaining recoverable reserves of gas in the three fields represent more than 80% of the total discovered gas rese rves in croatia. these gas accumulations exist in reservoirs of complex lithology, various porosity types and generally low permeability. the reservoirs are also 22 24 >\j i 1-' \..f' / secondary porosity 201 fig. 9 cross scction of obod rcscrvoir, cro­ atia (aft cr turajllc ct ai., 1979). characterised by high pressure and high temperatures, and the presence of corrosive and toxic gases, such as co2, h2s and hgs. bccausc of thcse difficulties, the existence of significant amounts of bypassed gas is a distinct possibility. 8. conclusions and recommendations croa tia needs to characterise and evaluate its bypassed hydrocarbon potential reserves. this include rcmaining unrecovered mobile oil and gas assoc iated with complex heterogeneous rescrvoirs , and additional recovery potential and related econom ic benefits that could result from the application of innovative improved technologies. an analytical system needs to be developed [or the characterisation and evaluation of bypassed hydrocarbons. the systern would consist of comprehensive databasc contain ing detailed rock and f lu id properties, geologic in formation, and production and dcvelopmcnt history for the pannonian basin reser­ voirs. continuation of research and developmcnt efforts are needed in the areas of d irect ional drilling and com­ pletion, 3-d seismic imaging, improvcd integration of logging and seismic clata, and development of geologic models for co mplex environmenl. the research and development could effectively be mct through collabo­ rative effort between ina, the university, and govern­ ment. 202 9. references bourgoyne. at jr. & kimbrell. w. ( 1994): development of improved methods for locat in g large areas of bypassed oil in louisiana. report prepared for doe under contract #de-fg07891012842. cox. 1'.1'. (1980): the economic aspects of marginal field development in an onshore environmcnt.­ spe paper 9023. diaz. d .. bassiouni. z .. kimbrell. w. & wol­ cot!~ , j. (1996): screening criteria for application or carbon dioxide miscible displacement in watcr­ r100dcd reservoirs conta ining light oil.spe paper 35341. gould. t.l. & sarem. a.m. (1989): infill drilli ng for in cremental recovcry.jour. pel. tech., march 1989. 229-237. horvat. d. (1995): molve natural gas complex­ backbone of croatian energy policy.nana, 46/1 , 23-29. zagreb. l.c.r. (1996): an evaluation of knowo remaining oil resources in piercement salt dome reservoirs in the gulf of mexico.report prepared by rcf under doe contract #de-ac22-92bc 14831. feb. 1996. geologia croalica 49(2 lepski. b .• wolcott. j. & bassiouni. z. (1995): physical modelling of' the oil displacement by gas in watcrfloodcd zoncs.paper presented at spe regional symposium on improved oil recov­ ery in the gulf region, ai-ain, dubai. peden. j.m. & tweedie. a.a.p. (1995): the appli ­ cation of horizontal and other non-conventional wells for the improvement of hydrocarbon recov­ ery in both mature and new fields.paper present­ ed at the regional symposiulll on improved oil recovery in the gulf region, ai-ain, dubai. turajlic. y .. mateljak. m. & devic. t . (1979): comparative presentation of deposits in the oil fields benicanci, obad and ladislavci -kucanci and their studics.3rd annual meeting of scientif­ ic cou nci l for petroleum of yugos lav academy or sciences and arts, proceedings, 2, 643-658, zagreb. vlasic. b. & bauk, a. (1994): possibilities of oil and gas exploration and production in the republic 01' croatia. nafta. 45/5 . 263-272. zagreb. geol. croat. 49/2 169· 170 zagreb 1996 professiollol papei' the fu ndamental economic issues of petroleum geological explorations in croatia boro vlasic ' and zvonimir hernitz' proceedings the section of geology, geophysics and geochem­ istry of th e scie ntifi c cou ncil for petroleum of th e croatian academy or sciences and arts has already o rgani sed scientific meetings on seve ra l occasio ns. these meetings were almost witholl t exception con­ cerning geological -geophysical aspects of explo rati on for oil and gas as we ll as the application of spec ifi c exp loration methods. thi s was unde rstandabl e given the socia-economic conditions present a l those times. the change in social envi ronment gave the economical aspect of ex ploration and production far g reater impor­ tance for it can significantly influcnce the final resu lt as well as knowledge on gcologic-geophysical conditions. bccause not many in croatia have occu pied themselves wi th such and re lated matters it was our a im to inform [he broade r profess ional publi c wi th how thi s was applied in other oil -produc ing coulltries. t he parti ci pa­ tion o f inte rnational ex perts gave thi s sympos ium an international character. approxi mate ly two years ago, the management o f the ina-nn flaplin company mentioned the possi bility of orga ni s ing an advi sory mccting to discuss the eco­ nomi c factors re levant to the exploration of petroleum. both the min istry o f science and technology and min­ is try of economic affa irs showed the ir iillerest. l na-naflap lin is the national oil -company of c roat ­ ia. it covers a wide spectrum of activ it ies expected of any such oil company from basic exploration and geo­ phys icalmeasuremenls to the drilling and production of hydrocarbons both inland and abroad. numerous explo­ ration s have been carried o ut in foreign count ries such as angola, tunisia , albania, egypt, libya, and a signi­ ficant ex pansion of th ese activi ties is ex pected in the future. othe r bus iness agreement s wit h in ternational partners have been made, one example being the most recen t arrangement on gas production with the italian company agip. all o f these s llccess ful business re lations creatc a need fo r the croatian petroleum economy to systemati ­ ca ll y enhance its bonds with the world and to be con­ necled to the world-wide ci rculation of scientific infor­ mation. croatia is a counlry in tran sition. not the only 1 ina-naflilplin . .subiceva 29, hr-loooo zagreb. croatia. one. this process has slart ed in all the countries of the form er eas tern block. it is also noted that in some west­ ern countries privati sa tion of the petro le llm economy occurs. t he croatian pe troleum econom y has undergone rapid expansion aft er world war n, but under the con­ ditions of" a " plan economy". of course, everything had it' s pri ce then as well as today. however the price in those times e ither d kln 't play an important role in dec i­ sion making, o r ihe ex penditures were not transparent enough. it is hard to be lieve that the techno-econom ical param eters were conveni ently omitted from the reports on reserves although their importance was well-known. it is onl y in recent years that , according to the latest " bylaw on the data acquisition , ev idenc ing and de te r­ mination of reserves or mineral deposits and balanc ing of reserves" from 1992 that the detailed analysis oj" the rentabi lit y of each and eve ry field is req uired. these matters were the basic reason fo r organising the sympo­ sium. an optimal and rat iona l approach to the explorati on of minera l reso urces represents the ultimate scicntific goal in the field of economic geology. initially, explo­ ra ti on makes poss ibl e the discovery of oil and gas pools. th is is fo ll owed by exp lo ra tion carried out for the purpose of the realis tic es t imati o n of oil and gas reserves, and phase three comprises exp lora tion proce­ dures carried out in the course of product ion it self. all of these ex plorations ex hibit a multidisciplinary charac­ te r, in va rious port ion s they inc lude the res ults 0 1" a number of scient ifi c disc iplines, primarily geology, geo­ physics and petroleum engi neering. t he ai m is [0 follow the advance or exploration pro­ cedures across the world in croatia. obviolisly, the pre­ sentation o f the results obtained in this sense is of great importance fo r our country, and that 's why the princ ipal objective of the symposium was to give a review of the possi ble solutions for a sys tem to intensify exploration for the purpose of increasing the recoverable oil and gas reserves. we ex pect the lec tures (o ral presen tations) and di s­ cussions to address th e prospectivity of exp loration 2 universit y o f z1.grcb, fac ulty o f mi ning, geology & petroleum engineering, pierollijcva 6, p.o. box i !:!6, hr -loooo zagreb, croatia . 170 areas with i.i rational way of carry in g ou t petrol eum ­ geologica l ex plora tions, thc techno-econom ic va luation of pc tro leum -gcol og ical projects, petroleum-re lated leg­ isla tion and problems of a petroleum economy in transi­ tion. the explo ration in croatia, both in part of the pan­ nonian basin and in the adriatic off-shore is s till ineom­ plcte. in the pannonian basin special atten tion has to be paid to non-s tructural , i.e. stratigraphic types of plays as well as to the rocks underlying tertiary depos its. th e re will be an interesting opportun it y to di sc li ss the suggestions on the possibility of acqui siti on of pregcologi;, cw;l lic;149{2 viously de termi ned and explored o il reserves in foreign countries. a modernisat ion o f the men tioned by-law on reserves will also be necessary in order to bring it in line wi th international standards. the contemporary by­ law, a lthough actually not old, is in fac t mere ly a mod i­ fi cation of one inherited from the old s tate in accor­ dan ce to the actual needs. alternatively, the recently published es timation of va lue of hydrocarbon rese rves of the fi elds d iscovered in croatia showed that we were too rigorous with these reserves, and that the oil and gas a re more va lu able than previously though t. 05 vrsaljko et al.indd 1. introduction the middle miocene (upper badenian and sarmatian) deposits cover a large area of north croatia, and their lithological and stratigraphic characteristics have been studied both at the surface and in the subsurface. their general evolutionary characteristics have been primarily based on their palaeoecological indications from the fossil fauna. in that sense, upper badenian sediments are characterized as marine while the sarmatian sediments are characterized as brackish or of reduced middle miocene (upper badenian/sarmatian) palaeoecology and evolution of the environments in the area of medvednica mt. (north croatia) davor vrsaljko1, davor pavelić2, mirjana miknić1, mato brkić1, marijan kovačić1, ivan hećimović1, valentina hajek-tadesse1, radovan avanić1 and nenad kurtanjek1 salinity (kochansky-devide, 1944; šikić, 1967; šikić et al., 1979; bajraktarević, 1980; kochansky-devide & bajraktarević, 1981;basch, 1983; avanić et al., 1995; vrsaljko et al., 1995a, b, 2005; vrsaljko, 1999; avanić et al., 2003; pavelić et al., 2003). the upper badenian and sarmatian deposits at several localities on medvednica mt. illustrate specific types of sedimentation (fig. 3). these were developed in various lithologies reflecting evolution of different environments in a relatively small area, dominated by carbonates in the late badenian, and siliciclastics in the sarmatian. additionally, the transition from the late badenian to the sarmatian resulted in different types of boundary between these deposits characterized by unconformities and a conformity (figs. 5 & 6). evolution of the environment may have been controlled by specifics such as characteristics of the preneogene basement, erosion intensity, water energy and local tectonics. however, since the basin evolution indicates a transgressive–regressive succession in the late badenian and a new transgression in the sarmatian, typical for central paratethys and the pannonian basin system, important regional external controls on sedimentation should be taken into account, including the opening and closing of an oceanic connection, climate and regional tectonic events (rögl & steininger, 1984; kovač et al., 1997; hardenbol et al., 1998; pavelić, 2001; pavelić et al., 2003; vrsaljko et al., 2005). 2. geological setting miocene deposits of the investigated area belong palaeogeographically to the south-western margins of central paratethys (figs. 1 & 2), and geotectonically to the pannonian basin system (pavelić, 2001). miocene deposits on the medvednica mt. disconformably overlie mesozoic basement, and contacts with palaeozoic/mesozoic basement are tectonic–erosional (šikić et al., 1979; basch, 1983; avanić et al., 2003). triassic dolomites and limestones occur in the sw part, while the central and ne parts of medvednica geologia croatica 59/1 51–63 11 figs. 2 tabs. zagreb 2006 key words: middle miocene, palaeoecology, environments, stratigraphic boundaries, medvednica mt., north croatia, central paratethys. 1 croatian geological survey, sachsova 2, p.o. box 268, hr-10000 zagreb, croatia; e-mail: dvrsaljko@hgi-cgs.hr 2 university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, hr-10000 zagreb, croatia. abstract in the area of medvednica mt., the upper badenian and sarmatian deposits are divided into four facies associations: (a) deposits of a small carbonate platform represented by breccia, conglomerates, biocalcirudites, biocalcarenites and biocalclutites; (b) open-sea deposits composed of marls with intercalations of clay; (c) nearshore deposits of reduced salinity composed of conglomerates, sandstones, biocalcarenites, biocalcirudites and biocalclutites, and (d) lagoonal deposits represented by spongitic calclutites with clay, marl and sand intercalations. deposits of these facies associations contain numerous and very diverse fossil species with very different palaeoecological characteristics, from shallowand deeper-water normal marine to shallowand deeper-water environment of reduced salinity, even of fresh-water. the transition from late badenian to sarmatian deposition was characterized by three different unconformities and one conformity. unconformities are located between different lithologies reflecting an amount of uplifting and erosion at the end of the badenian. the occurrence of an angular unconformity suggests the influence of local tectonics. the middle miocene deposition shows different local variations but generally fits with the evolution of central paratethys and the pannonian basin system. 52 geologia croatica 59/1 mt. are dominated by cretaceous deposits (magmatic– sedimentary complex). miocene deposits of the investigated area were divided into three parts by kochansky-devide (1944): (1) sw part called the “dolje development”, (2) a middle part, the “čučerje development”, and (3) the north-eastern part called the “zelina development”. within the “doljanski envelopment”, the first miocene sediments are fine-grained deposits and biogenic limestones of badenian age transgressive over the mesozoic basement. this succession also occurs in the northerneastern part of medvednica mt., known as the “zelina development”. in the central part of medvednica mt. (“čučerje development”), the first miocene sediments were lower miocene (ottnangian) freshwater sediments followed by marine (karpatian) deposits, which are partly equivalent to the “rzehakia layers”. these sediments were succeeded by the badenian coarsegrained sediments, tuffitic marls and fine-grained deep marine deposits, which can be compared with isochronous miocene deposits of the vienna basin (central paratethys), known as “schlier”. upper badenian deposits are approximately 30 to 70 m thick on the slopes of medvednica mt., and the maximum thickness of the sarmatian deposits is 50 m (after basch, 1983). 3. description and interpretation of facies four sections were studied on the slopes of medvednica mt. – podsusedsko dolje, gornje vrapče, krvarić and donje orešje (figs. 2, 3 & 5). the studied deposits belong to the upper badenian and sarmatian, and their total thickness is 80 m. based on their lithological characteristics and faunal content (tables 1 & 2), these sediments were grouped into four facies associations suggesting different palaeoecological conditions (figs. 5 & 6). 3.1. facies association a: deposits of a small carbonate platform deposits of this facies association (fig. 4) were studied in the gornje vrapče, krvarić and donje orešje columns (fig. 5), consisting of breccia, conglomerates, biocalcirudites, biocalcarenites and biocalclutites. breccia and conglomerates are composed mostly of fragments of upper triassic dolomites and upper cretaceous limestones reflecting the composition of the basement. the siliciclastic content is very low. biocalcirudites, biocalcarenites and biocalclutites are almost structureless, but cross-bedding can be seen fig. 1 palaeogeographic map of central paratethys: middle miocene (after rögl, 1998). 53vrsaljko et al.: middle miocene (upper badenian/sarmatian) palaeoecology... sporadically. these deposits consist mostly of fragments or whole skeletons of shallow marine organisms: algae lithotamnion sp. which dominate, large molluscs (ostrea sp., lucinoma borealis, pecten sp., isocardia cor, panopea menardi, conus sp., chlamys elegans and many cardiids), bryozoans, serpulids, echinoids, foraminifera of ammonia viennensis–elphidium crispum zone: lobatula lobatula, c. pseudungerianus, elphidium fichtelianum, e. crispum and ammonia viennensis, and ostracods: cytheretta tenuipunctata dentata and senesia cf. philippii. these organisms document fully marine conditions during late badenian time. una kupa sava sava dunav drava drava èesm a ilov a bosut lonja krapina mura gl ina zagreb karlovac žumbera k mt. osijek ivanšèica mt. moslava ka mt. è kalnik mt. papuk mt. požeška mt. psunj m t. dilj mt. krndija mt. našice 0 50 100km bosnia & herzegovina middle-upper miocene deposits zagreb split c r o a t i a a d r i a t i c s e a n o r t h e r n c r o a t i a medvednica mt. h u n g a r y d i n a r i d e s 4 1 2 3 16 00"0 46 00 " 0 s l o v e n i a fig. 2 study area: (a) croatia; (b) northern croatia; (c) medvednica mt.: location of geological columns (1 – podsusedsko dolje, 2 – gornje vrapče, 3 – krvarić, 4 – donje orešje). a b c 54 geologia croatica 59/1 the occurrence of coarse-grained sediments, i.e. breccia and conglomerates overlying the basement, and their petrographic composition, indicate erosion and reworking of the basement material during the early marine transgression, and deposition within high-energy shallow-water environments (fig. 6). biocalcirudites, biocalcarenites and biocalclutites suggest lower energy conditions compared to those of the breccia and conglomerates. their faunal association documents favourable palaeoecological conditions for the expansion of organisms in a shallow-marine environment formed over a carbonate basement. these organisms were reworked by strong currents as indicated by the grain-size of sediments and fragmentation of skeletons. additionally, cross-bedding suggests deposition by traction currents generated by tides or waves. the sedimentary environment was probably that of an isolated small carbonate platform formed over the previous land highs protected from terrestrial influence. on this platform algal banks were developed, colonized by a shallow-water fauna which was penecontemporaneously reworked and resedimented by strong currents within the same environment. 3.2. facies association b: open sea deposits these deposits were studied at the donje orešje locality (fig. 7). they overlie sediments of a small carbonate platform (figs. 5 & 6). the association is represented by marls with several intercalations of clay (fig. 5). the bed thicknesses vary between 3 and 15 cm. marls are massive and strongly bioturbated, comprising a rich association of foraminifera of the bulimina–bolivina zone: pavonitina styriaca, reophax sp., cribrostomoides columbiensis, alveolophragmium species facies association mollusca lucinoma borealis (linné) a, b, d palliolum zoellikoferi (bittner) b, d isocardia cor (linné) a, d panopea menardii deshayes a chlamys elegans (andrz.) a, b glycymeris cor (partsch) a, b corbula gibba (olivi) d callista chione (defrance) d ostrea sp. a natica sp. d venus sp. b foraminifera ammonia viennensis (d’orbigny) a bolivina dilatata reuss d bulimina elongata d’orbigny d praeglobobulimina pyrula (d’orbigny) b, d globocassidulina oblonga (reuss) b, d lobatula lobatula (walker & jacob) a cibicidoides pseudoungerianus (cushman) a elphidium crispum (linné) a e. fichtelianum (d’orbigny) a uvigerina semiornata d’orbigny b, d u. venusta franzenau b, d pavonitina styriaca schubert b, d heterolepa dutemplei (d’orbigny) b, d globigerina diplostoma reuss b g. bulloides d’orbigny b, d orbulina universa d’orbigny b velapertina indigena (luczkowska) b pappina neudorfensis (toula) d globorotalia scitula (brady) d orbulina suturalis brönnimann d reophax sp. b, d alveolophragmium crassum (reuss) b, d spirorutilus carinatus (d’orbigny) d ostracoda aurila angulata (reuss) d callistocythere canaliculata (reuss) d cnestocythere lamellicosta triebel d hermanites haidingeri (reuss) d loxoconcha punctatella (reuss) d l. hastata (reuss) d xestoleberis glabrescens (reuss) d senesia cf. philippii (reuss) a cytheretta tenuipunctata dentata bretenska d, a others algae (lithotamnion sp.) a, b hydrozoa a, b bryozoa a, b echinoids a, b, d ostracodes a, b, d fishes a, b, d terrestrial flora a, b, d table 1 the important fossil association of the late badenian on medvednica mt. species facies association mollusca ervilia dissita (eichwald) c musculus sarmaticus gatuev c modiolus sp. c mactra sp. c gibbula sp. c irus sp. c cerithium sp. c cardium vindobonense (partsch) c c. gleichenbergense (papp) c planorbidae sp. nov.? d foraminifera elphidium hauerinum (d’orbigny) c e. reginum (d’orbigny) c e. josephinum (d’orbigny) c rosalina obtusa d’orbigny c articulina problema bogdanowicz c sinoloculina volhynica (didkowskiy) c sinzowella novorossica (karrer & sinzow) c porosononion granosum (d’orbigny) d ostracoda candona cf. oblonga (sars) d aurila merita (zalanyi) d a. mehesi (zalanyi) d loxoconcha kochi (mehes) d darwinula cylindrica straub d pseudocandona fertilis triebel d others characea; chalmasia moreleti pokorny d fishes d, c spongia d, c serpulids d, c algae d, c terrestrial flora d, c table 2 the important fossil association of the sarmatian on medvednica mt. 55vrsaljko et al.: middle miocene (upper badenian/sarmatian) palaeoecology... crassum, uvigerina semiornata, u. venusta, heterolepa dutemplei and astrorhyzidae, and predominating planktonic species globigerina diplostoma, g. bulloides, orbulina universa and velapertina indigena (tables 1 & 2). some molluscs occur sporadically, such as lucinoma borealis, palliolum zoelikoferi, glycymeris cor, nassa sp., venus sp., chlamys sp. and cardium sp. fragments of echinoids and bryozoans are rare. this foraminiferal association indicates deposition from the neritic to the basinal area (about 100 m depth, according to spezzaferri et al., 2005; hohenegger, 2005). in the uppermost part of this facies association agglutinated forms of foraminifera are absent, excluding pavonitina styriaca. the clay intercalations may be explained as a consequence of a temporary but strong terrestrial influence. the whole aforementioned faunal association suggests an open sea environment and deposition of marls and clays during the late badenian. fig. 3 stratigraphic scheme (modified after rögl, 1998; hardenbol et al., 1998). fig. 4 facies association a: deposits of a small carbonate platform; krvarić locality. 56 geologia croatica 59/1 3.3. facies association c: nearshore deposits of reduced salinity deposits of this association (fig. 8) were studied in the podsusedsko dolje, gornje vrapče and krvarić localities (fig. 5). facies association c is composed of conglomerates and sandstones, and biocalcarenites, biocalcirudites and biocalclutites (figs. 5 & 6). conglomerates and sandstones occur in the lowest part of facies association c. pebbles average 3 cm in diameter. cobbles up to 15 cm in diameter are uncommon. sandstones are coarse-grained and include some fine-grained pebbles. the composition of fragments is very different to older deposits, reflecting the composition of the basement. fragments of the upper badenian marls up to 30 cm long are also frequent and are found fig. 5 stratigraphic columns: 1 – podsusedsko dolje, 2 – gornje vrapče, 3 – krvarić, 4 – donje orešje. 57vrsaljko et al.: middle miocene (upper badenian/sarmatian) palaeoecology... in the lower part of the facies association. the sorting is poor. biocalcarenites, biocalcrudites and biocalclutites predominate in this facies association. they are horizontal to cross-bedded. the composition is characterized by a high content of molluscs, foraminifera and ostracods. the most frequent molluscs are cerithium sp., gibbula sp., mactra sp., irus sp., modiolus sp., ervilia dissita, cardium vindobonense, c. gleichenbergense and musculus sarmaticus. the foraminiferal association is represented by species of the elphidium reginum zone: elphidium reginum, e. josephinum, sinfig. 7 facies association b: open sea deposits; donje orešje locality. fig. 6 evolution of the environments; badenian–sarmatian deposits (idealized profile). 58 geologia croatica 59/1 zowella novorossica and rosalina obtusa. ostracods are aurila sp. and cytheridea sp. fragments of alga occur sporadically – chalmasia moreletti and characean girogonias. this fossil association indicates deposition in a shallow marine environment of reduced salinity. except for the sarmatian fossils, this facies association often includes resedimented fragments of upper badenian algae and foraminifera. oncoids, ooids and vadoids also occur. conglomerates in the lower part of the facies association indicate high-energy environments, while their structural and petrographic composition suggests strong terrestrial input and deposition in shallow water. the occurrence of the upper badenian fragments indicates erosion of those sediments on the land. biocalcarenites and biocalcrudites were probably deposited by traction currents in a shallow-water environment. biocalclutites indicate low-energy sedimentation. palaeoecological characteristics of the fauna additionally indicate shallow-water deposition in an environment of reduced salinity. imperforate foraminifera articulina problema, sinoloculina volhynica and sinzowella novorossica and encrusting foraminifera sinzowella caespitosa indicate the existence of small reefs or biostromes, while ooids (oncoids, vadoids) suggest low currents and the existence of sandy bars (friebe, 1994). strong inflow of fresh water very probably reduced the salinity of this environment. such ecological conditions generated the development of specific organisms. currents and oxic conditions enabled the expansion of life on the bottom on which epiphytic organisms evolved, including molluscs, foraminifera and ostracods. most of these organisms lived as vagile benthos which was very active on the bottom. at the same time, nubecularians built up small reefs. species of ervilias, mactras, iruses and cardiums lived on the muddy–sandy bottom feeding from the substratum. most of the gastropods from the family ceritidae, and some miliolid foraminifera existed in proximity to the fresh water inflow. 3.4. facies association d: lagoonal deposits based on their different lithology and palaeoecology, lagoonal deposits (fig. 9) are divided into two groups: spongitic calclutites (podsusedsko dolje and gornje vrapče localities), and clay, marl and sand intercalations (podsusedsko dolje, gornje vrapče and donje orešje) (fig. 5). spongitic calclutites are horizontally bedded and intensively bioturbated with bed thicknesses between 0.1–1.5 m. calclutites are characterized by a high content of biogenic remnants, such as the stone cores of monaxonid and triaxonid sponges, skeletons of crabs and fish, serpulids, echinoids, and an association of molluscs and foraminifera. some fragments of algae as well as small coal clasts also occur. the spirorutilus–praeglobobulimina–heterolepa foraminiferal association in spongitic calclutites is characterized by benthic species semivulvulina deperdita, spirorutilus carinatus, pavonitina styriaca, bolivina dilatata, bulimina elongata, uvigerina brunnensis, u. venusta, pappina neuderfensis and heterolepa dutemplei. planktonic species are very rare, but include globorotalia scitula, globigerina bulloides and orbulina suturalis. the most frequent molluscs are lucinoma borealis, isocardia cor, palliolum zoelikoferi, corbula fig. 8 facies association c: nearshore deposits; krvarić locality. 59vrsaljko et al.: middle miocene (upper badenian/sarmatian) palaeoecology... gibba, callista chione and natica sp. the most common ostracod species include aurila angulata, callistocythere canaliculata, cnestocythere lamellicostata, hermanites haidingeri, loxoconcha punctatella, l. hastata and xestoleberis glabrescens. this fossil association documents a fully marine environment and deposition in the late badenian (vrsaljko et al., 1995a; hajek-tadesse, 2006). the grain-size of the calclutites indicates deposition from suspension while the lack of coarse-grained intercalations suggests an environment protected from stronger intrabasinal influence. benthic organisms indicate deposition on the marine bottom up to 70 m depth. the absence of strong current indicators and the rare occurrence of planktonic foraminifera can be explained as a consequence of the restricted connection with the open sea, i.e. sedimentation in a lagoon or bay. the bottom of the lagoon was muddy–silty and most of the benthic organisms lived burrowed in the substratum. some gastropods such as natica sp. were carnivorous. there were also coprophags (serpulids, echinoids and some molluscs). a restricted marine connection enabled conditions needed for the existence of a greater quantity of planktonic foraminifera. clays and marls are horizontally bedded and almost laminated. sometimes these sediments are massive. sands occur as thin intercalations within this group of sediments. a rich fossil association is found in the marls (table 2). an elphidium–protelphidium–porosononion foraminiferal association is an important palaeoecological characteristic of the marls. this association is very similar to the one described in facies association c. the most common species are elphidium josephinum, e. hauerinum, e. macellum, and porosononion granosum. there are also some ostracods, remnants of fish skeletons, molluscs and a terrestrial flora. molluscs ervilia sp., mactra sp. and cardium sp. also occur in both facies associations c and d, but are of smaller dimensions in the facies association d. ostracod species aurila merita, a. mehesi, loxoconcha kochi infer reduced salinity, while candona cf. oblonga, darwinula cylindrica and pseudocandona fertilis are fresh-water species. the whole fossil association documents generally reduced salinity within sarmatian environments. some fresh-water ostracods may reflect stratification of the water, similar to the recent black sea. characean girogonias and gastropods planorbidae occur sporadically. clays and marls settled out from suspension while thin sandy intercalations may represent turbidites deposited from weak gravity flows. the lack of planktonic foraminifera suggests a restricted connection with the open sea (šikić, 1967; kochansky-devide & bajraktarević, 1981; vrsaljko et al., 1995a). this facies association and its palaeoecological characteristics indicate deposition in a lagoon or bay, which had an input of fine-grained terrestrial material. the foraminiferal association is strongly reduced in the number of constituent species and diversity compared to that of the late badenian. this can be explained by the formation of an environment of reduced salinity (tables 1 & 2), and is supported by the observed increase in the number of ostracods and the occurrence of fresh-water species. 4. characteristics of the badenian– sarmatian boundary the transition from the late badenian to the sarmatian is very variable in the relatively small studied area of mt. medvednica. it is characterized by three types of unconformities, and a conformity. fig. 9 facies association d: lagoonal deposits; gornje vrapče locality. 60 geologia croatica 59/1 the gornje vrapče locality was characterized by very strong erosion of the upper badenian deposits and their resedimentation in the beginning of the sarmatian (figs. 5 & 6). the unconformity is very clear, marked by desiccation cracks in the uppermost badenian deposits and reworked fragments of marls with upper badenian fauna within transgressive sarmatian deposits. the krvarić locality is very specific (fig. 5). the lithology of the upper badenian and sarmatian sediments is similar and represented by biocalcarenites that partly hides the unconformity. the hiatus is recognizable by the occurrence of a thin irregular clay–bauxite interbed which documents short-lived emersion before the onset of the sarmatian transgression (fig. 10). in the podsusedsko dolje locality (figs. 5 & 11) a typical angular disconformity between the upper badenian and sarmatian is found. the dip of the sarmatian deposits is ca. 10° less than the dip of the upper badenian sediments. the sarmatian succession begins with conglomerates and sandstones which represent a transgressive lag. it is overlain by fine-grained sediments deposited in a lagoon of reduced salinity. the boundary between the upper badenian and sarmatian sediments in the donje orešje locality is characterized by its conformity (fig. 5). the sedimentation style is similar in the late badenian to the sarmatian. the transition is characterized by a gradual change of palaeoecological characteristics from a normal marine to reduced salinity fauna. this conformable transition indicates sedimentation in the deeper part of the basin which was not significantly affected by the sea-level fall at the end of the badenian. 5. evolution of the environments the onset of late badenian deposition is characterized by transgression and formation of a normal marine environment. this transgression was very probably a consequence of the opening of a connection between central paratehys and the indo–pacific ocean due to eustatic sea-level rise (steininger et al., 1978; rögl & steininger, 1984; kovač et al., 1997; hardenbol et al., 1998; rögl, 1998). pre-existing land could have been formed due to fault-block rotation and uplifting in the early badenian, representing the end of the syn-rift phase (pavelić, 2001; pavelić et al., 2003). this uplift enabled strong erosion of all syn-rift deposits and the occurrence of pre-neogene basement on the surface, including upper triassic dolomites and upper cretaceous limestones. these rocks provided favourable conditions for the evolution of small carbonate platforms on which different shallow-water organisms started to develop. algal banks with lithotamnion sp. predominated, but ecological conditions also supported the expansion of many different shallow-water organisms, such as bivalves, gastropods, bryozoans, echinoids, foraminifera etc. these carbonate platforms were protected from terrestrial influence. however, strong currents generated by tides or waves caused reworking of material on the bottom and resedimentation. similar interpretations have been made for deposits from central medvednica mt., eastern croatia and the styrian basin, supporting the ideas that in sw central paratethys, several small carbonate platforms existed in the beginning of the late badenian (schmid et al., 2001; avanić et al., 2003; pavelić et al., 2003; vrsaljko, 2003; vrsaljko et al., 2005). fig. 10 the badenian–sarmatian boundary; krvarić locality. 61vrsaljko et al.: middle miocene (upper badenian/sarmatian) palaeoecology... a continuation of sea-level rise generated deepening and the evolution of two different environments with fine-grained deposition. in ne medvednica mt. (donje orešje locality; fig. 2) open marine environments were formed, characterized by the deposition of marls on the steep slope reaching depths of 100 m or more. open marine conditions enabled the evolution of numerous and diverse planktonic foraminifera. in contrast, in sw medvednica mt. (podsusedsko dolje and gornje vrapče localities; fig. 2) ca. 70 m deep lagoon or bay formed in the shallow sea. this environment was partly protected from the open sea, and enabled the existence primarily of benthic organisms, while the number and diversity of planktonic organisms was restricted (tables 1 & 2). this difference in two contemporaneous environments could be explained by palinspastic reconstruction. the position of the podsusedsko dolje and gornje vrapče localities was close to the dinarides, i.e. to the land which may have surrounded the lagoon or bay (figs. 1 & 2). the donje orešje locality was more distal from the land, i.e. closer to the central part of central paratethys, and there the influence of the open sea was more important (figs. 1 & 2). upper badenian deposition in the central part of medvednica mt. also occurred in an open marine environment, which supports this palinspastic reconstruction (avanić et al., 2003). the end of the badenian was characterized by sealevel fall causing shallowing. it has been explained by the beginning of the isolation of central paratethys from the ocean (papp & seneš, 1974; seneš, 1974; rögl & steininger, 1984; kovač et al., 1997; rögl, 1998; vrsaljko, 1999, 2003; pavelić, 2001; pavelić et al., 2003; vrsaljko et al., 2005). in north-eastern medvednica mt., shallowing of the open sea did not have a significant influence on sedimentation, suggesting that it was deep enough to maintain relatively similar deposition. in its sw part, shallowing caused emergence and the formation of small islands, i.e. an archipelago, and was followed by a new transgression in the sarmatian. this emergence indicates external controls on deposition. in the gornje vrapče locality the unconformity between the upper badenian and sarmatian deposits was marked by strong erosion and resedimentation of lagoonal marl fragments up to 30 cm long, together with the first transgressive deposits. sarmatian sediments indicate significant sealevel fall that exposed relatively deep-water upper badenian deposits on the surface. at the krvarić locality, the unconformity is marked by a thin clay–bauxite interbed between shallow-water deposits, suggesting weaker erosion, and insignificant sea-level fall at the end of the late badenian (figs. 5 & 10). the unconformity which occurs at the podsusedsko dolje locality may be used for interpretation of this differential shallowing. since this unconformity is of an angular type, it was very probably caused by uplift due to tectonics (figs. 5 & 11). strong uplift which primarily caused the exposure of relatively deep, lagoonal deposits on the surface, additionally resulted in the inclination of the upper badenian beds. upper badenian sedimentation belongs to the post-rift phase, which is generally characterized by subsidence due to cooling of the lithosphere, but local tectonics may also be expected in its earliest part (kovač et al., 1997; pavelić, 2001; pavelić et al., 2003). so, it can be summarized that local tectonics in the earliest post-rift phase probably controlled sedimentation in that area of medvednica mt. (avanić et al., 2003). the onset of sarmatian deposition was a result of the beginning of a transgression (šikić et al., 1979; fig. 11 the badenian–sarmatian boundary; podsusedsko dolje locality. 62 geologia croatica 59/1 basch, 1983; vrsaljko et al., 1995a, b; vrsaljko, 1999). the connection of central paratethys with the ocean was restricted, but a change of climate to more humid one, could generate sea-level rise (pikija et al., 1989; friebe, 1994). erosion of terrestrial material and its resedimentation was an important characteristic during that transgression. after shallow-water deposition, continued sea-level rise formed an environment approximately 100 m deep characterized by dramatically different ecological conditions. due to the restricted connection with the sea, salinity was reduced, resulting in the occurrence of new species, particularly benthic organisms: foraminifera, molluscs, ostracods and characeans (rögl & steininger, 1984). 6. conclusions on the slopes of medvednica mt., the late badenian was characterized by formation of fully marine conditions, and the development of small carbonate platforms over pre-existing land due to the marine transgression. the sea-level rise caused deepening and evolution of the open sea environment in its ne part, and a lagoon or bay in its sw part. the formation of the lagoon or bay may be a consequence of the proximity of the dinarides which represented land at that time, while an open sea environment developed closer to the central part of central paratethys. deposition was strongly controlled by eustacy, and was mostly protected from terrestrial influence. at the end of the late badenian, local tectonics generated differential uplifting, shallowing and exposure of the upper badenian deposits on the surface in the sw part of mt. medvednica, while in its ne part sedimentation continued into the sarmatian. the late badenian represents the onset of the post-rift phase, generally characterized by thermal subsidence, but tectonics still controlled sedimentation locally (rögl & steininger, 1984; pavelić, 2001; pavelić et al., 2003). the beginning of the sarmatian was characterized by a new transgression, erosion and resedimentation of the upper badenian deposits, and formation of a relatively deep-water environment of reduced salinity. such a specific environment, influenced by the input of finegrained terrestrial material enabled development of species of different palaeoecological characteristics. acknowledgements this work represents a part of the multidisciplinary geological investigation which was performed from 1991 to 1997 within the project entitled “clastic–carbonate neogene deposits of medvednica mt.”, which formed part of the project “geological map of the republic of croatia, scale 1:50000”, financed by the ministry of science and technology of the republic of croatia (project no. 0181001). the authors are grateful to reviewers, stjepan ćorić (vienna) and alfred dulai (budapest), who helped to improve the manuscript. 7. references avanić, r., brkić, m., miknić, m., šimunić, al. & pavelić, d. (1995): gornjobadenske i sarmatske naslage gornje kustošije [the upper badenian and sarmatian deposits of the gornja kustošija – in croatian].– in: šikić (ed.): geološki vodič medvednice, 71–73, institute of geology, zagreb. avanić, r., kovačić, m., pavelić, d., miknić, m., vrsaljko, d., bakrač, k. & galović, i. (2003): the middle and upper miocene facies of mt. medvednica (northern croatia).– in: vlahović, i. & tišljar, j. (eds.): evolution of depositional environments from the palaeozoic to the quaternary in the karst dinarides and the pannonian basin. 22nd ias meeting of sedimentology, opatija – september 17–19, 2003, field trip guidebook, 167–172. bajraktarević, z. (1980): mikropaleontološka i biostratigrafska istraživanja tortona (badena) nekih lokaliteta samoborskog gorja, plešivice i marija-goričkih brda (micropaleontologic and biostratigraphic investigation of the tortonian (badenian) of some localities of samoborsko gorje mts., plešivica mt. and marija-gorička brda mts.).– geol. vjesnik, 31, 37–47. basch, o. (1983): osnovna geološka karta sfrj 1:100.000. tumač za list ivanić-grad, l 33–81 (basic geological map 1:100.000, geology of the ivanić-grad sheet).– geološki zavod zagreb (1980), savezni geol. zavod, beograd, 81 p. friebe, j.g. (1994): serpulid–bryozoan–foraminiferal biostromes controlled by temperate climate and reduced salinity: middle miocene of the styrian basin, austria.– facies, 30, 51–62. hajek-tadesse, v. (2006): miocenski ostrakodi sjeverne hrvatske (miocene ostracods of northern croatia – in croatian with an english abstract).– unpublished phd thesis, faculty of science, university of zagreb, 179 p. hardenbol, j., thierry, j., farley, b., jacquin, t. & vail, p. (1998): mesozic and cenozoic sequence chronostratigraphic framework of european basins.– in: graciansky, p., hardenbol, j., jacqiun, t. & vail, p. (eds.): mesozoic and cenozoic sequence stratigraphy of european basins. sepm special publication 60. hohenegger, j. (2005): estimation of environmental paleogradient values based on presence/absence data: a case study using benthic foraminifera for paleodepth estimation.– palaeogeography, palaeoclimatology, palaeoecology, 217, 115–130. kochansky-devidé, v. (1944): fauna marinskog miocena južnog pobočja medvednice–zagrebačke gore (miozäne marine fauna des sudlichen abhanges der medvednica, zagreber gebirge) [fauna of marine miocene of southern flanks of the medvednica mt. and the zagrebačka gora mt. – in croatian and german].– vjestnik hrv. drž. geol. zavoda i hrv. drž. geol. muzeja, 2/3, 171–272. 63vrsaljko et al.: middle miocene (upper badenian/sarmatian) palaeoecology... kochansky-devidé, v. & bajraktarević, z. (1981): miocen (baden i sarmat) najzapadnijeg ruba medvednice (miozän (baden und sarmat) des westlichen randes von medvednica gebirge, kroatien, jugoslawien) [miocene (badenian and sarmatian) of the westernmost rim of the medvednica mt. – in croatian and german].– geol. vjesnik, 33, 43–48. kovač, m., barath, i. & nagymarosy, a. (1997): the miocene collapse of the alpine–carpathian–pannonian junction.– acta geol. hungarica, 49, 445–458. papp, a. & seneš, j. (1974): grunzuge der entwicklung der fauna und die biozonen im sarmatien s. str. der zentralen paratethys [characteristics of the fauna development and biozones in the sarmatian s.str. of the central paratethys – in german].– in: papp, a., marinescu, f. & seneš, j. (eds.): chronostratigraphie und neostratotypen – miozän der zentralen paratethys – sarmatien. veda, slowakische akademie der wissenschaften, bratislava, 1974, bd. iv, 41–44. pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.– basin research, 13, 359–376. pavelić, d., avanić, r., kovačić, m., vrsaljko, d. & miknić, m. (2003): an outline of the evolution of the croatian part of the pannonian basin system.– in: vlahović, i. & tišljar, j. (eds.): evolution of depositional environments from the paleozoic to the quaternary in the karst dinarides and the pannonian basin. 22nd ias meeting of sedimentology, opatija–september 17–19, 2003, field trip guidebook, 155–161. pikija, m., šikić, k., tišljar, j. & šikić, l. (1989): biolititni i prateći karbonatni facijesi sarmata u području krašić–ozalj, središnja hrvatska [sarmatian biolithites and associated carbonate deposits in the krašić–ozalj area, central croatia – in croatian].– geol. vjesnik, 42, 15–28. rögl, f. (1998): paleogeographic considerations for mediterranian and paratethys seaways (oligocene to miocene).– ann. naturhist. mus. wien, 99a, 279–310. rögl, f. & steininger, f. (1984): neogene paratethys, mediterranean and indo–pacific seaways.– in: brenchey, p. (ed.): fossils and climate. wiley and sons, 171–200, london. schmid, h.p., harzhauser, m. & kroh, a. (2001): hypoxic events on a middle miocene carbonate platform of the central paratethys (austria, badenian, 14 ma).– ann. naturhist. mus. wien, 102a, 1–50. seneš, j. (1974): palaeogeographie der zentralen paratethys im sarmatien s.str. [palaeogeography of the central paratethys in the sarmatian s.str. – in german].– in: papp, a., marinescu, f. & seneš, j. (eds.): chronostratigraphie und neostratotypen – miozän der zentralen paratethys – sarmatien. veda, slowakische akademie der wissenschaften, bratislava, 1974, bd. iv, 140–154. spezzaferri, s., rögl, f., ćorić, s. & hohenegger, j. (2005): paleoenvironmental changes and agglutinated foraminifera across the karpatian/badenian (early/ middle miocene) boundary in the styrian basin (austria, central parathetys).– in: bubik, m. & kaminski, m.a. (eds.): proceedings of the sixth international workshop on agglutinated foraminifera. spec. publ., 8, 423– 459. steininger, f., rögl, f. & müller, c. (1978): geodynamic und palaeogeographische entwicklung des badenien [geodynamic and palaeogeographic development of the badenian – in german].– in: papp, a., cicha, i., seneš, j. & steininger, f. (eds.): chronostratigraphie und neostratotypen – miozän der zentralen paratethys – badenien. veda, slowakische akademie der wissenschaften, bratislava, 1978, bd. vi, 110–127. šikić, k., basch, o. & šimunić, a. (1979): osnovna geološka karta sfrj 1:100.000. tumač za list zagreb, l 33–80 (basic geological map 1:100.000, geology of the zagreb sheet).– institut za geološka istraživanja, zagreb (1972), savezni geološki zavod, beograd. šikić, l. (1967): torton i sarmat jugozapadnog dijela medvednice na osnovu faune foraminifera (torton und sarmat des sudlichen teiles der medvednica auf grund der foraminiferenfaunen) [tortonian and sarmatian of south-western part of the medvednica mt. on the basis of foraminifera fauna – in croatian and german].– geol. vjesnik, 20, 127–135. vrsaljko, d. (1999): the pannonian palaeoecology and biostratigraphy of molluscs from kostanjek–medvednica mt., croatia.– geol. croatica, 52/1, 9–27. vrsaljko, d. (2003): biostratigrafija miocenskih naslaga žumberačkog i samoborskog gorja na temelju mekušaca (biostratigraphy of miocene deposits from žumberačko and samoborsko gorje mts. on the basis of molluscs – in croatian, with an english abstract).– unpubl. phd thesis, faculty of science, university of zagreb, 147 p. vrsaljko, d., šikić, k., pikija, m., glovacki-jernej, ž. & miknić, m. (1995a): miocenske naslage gornjeg vrapča [the miocene deposits of the gornje vrapče – in croatian].– in: šikić (ed.): geološki vodič medvednice. institute of geology, zagreb, 61–66. vrsaljko, d., šimunić, al. & miknić, m. (1995b): naslage sarmata i panona kraj krvarića [sarmatian and pannonian deposits near krvarić – in croatian].– in: šikić (ed.): geološki vodič medvednice. institute of geology, zagreb, 69–71. vrsaljko, d., pavelić, d. & bajraktarević, z. (2005): stratigraphy and palaeogeography of miocene deposits from the marginal area of žumberak mt. and samoborsko gorje mts. (northwestern croatia).– geologia croatica, 58/2, 133–150. manuscript received march 14, 2006. revised manuscript accepted june 9, 2006. 64 geologia croatica 59/1 02 hernitz-kucenjak et al.indd 1. introduction in different geological periods, planktonic foraminifera were deposited over an extensive portion of the world oceans and seas, and are often found in large numbers. industrial application of planktonic foraminiferal biostratigraphic studies began in the middle of the last century in the gulf coast region of the usa and quickly spread through the principal oil-producing parts of the world (stainforth et al., 1975; boersma, 1988). this has resulted in the recognition of their usefulness for both local and regional biostratigraphic zonation and correlation (bolli & saunders, 1985; berggren et al., 1995). numerous biostratigraphic studies of planktonic foraminifera have originated from the former soviet union – the first zonal scheme for planktonic foraminifplanktonic foraminiferal biostratigraphy of the late eocene and oligocene in the palmyride area, syria morana hernitz kučenjak, vlasta premec fućek, renata slavković and ivan a. mesić era was published by subbotina (1947) for sections of the caucasus mountains. afterwards, a large number of planktonic foraminiferal studies were published, e.g. bolli (1957), blow (1979), toumarkine & luterbacher (1985), berggren & miller (1988), and others. a revised geochronology and geochronostratigraphic study was published by berggren et al. (1995). further investigations of the planktonic foraminiferal ranges from different parts of the world have provided knowledge for a new zonation (berggren & pearson, 2005; pearson et al., 2006). important biostratigraphical work on the palaeogene deposits in syria has been undertaken by krasheninnikov et al. (1996). a previous biostratigraphic investigation in the palmyride area, on material from deep exploration wells was done by hernitz kučenjak et al. (2005). in the present work, a planktonic foraminiferal fauna from three deep exploration wells jihar–1, jihar–4 and jihar–5 drilled in the palmyride area (fig. 1) has been examined. a rich, highly to moderately diverse and well preserved planktonic foraminiferal association enabled biostratigraphical zonation of the late eocene and oligocene deposits (fig. 3). on the basis of the composition of the foraminiferal assemblages, diversity, changes of test morphology and wall texture, palaeoecological and palaeoclimatic interpretations have been made. 2. material and methods the detailed biostratigraphic study was based on material from drill cuttings from three deep exploration wells (jihar–1, jihar–4 and jihar–5) drilled in the hayan exploration block in the palmyride area (fig. 1). samples for micropalaeontological analyses were taken at every 10 m in jihar–1 and jihar–5 wells and at 20 m intervals in the jihar–4 well. samples were soaked in water with a small amount of hydrogen peroxide and then washed under running water through 63 µm, 125 µm, 160 µm and 630 µm sieves. these four fractions were dried in a drier and from each fraction foraminifera were picked out onto micropalaeontological slides. microfossil associations were examined on a stereo microscope, whereas a detailed study of the geologia croatica 59/1 19–39 3 figs. 5 pls. zagreb 2006 key words: biostratigraphy, planktonic foraminifera, late eocene, oligocene, palmyride area, syria. ina – industrija nafte d.d., research and development sector, rock and fluid research lab. dept., lovinčićeva bb., 10000 zagreb, croatia; e-mail: morana.hernitz-kucenjak@ina.hr abstract three deep exploration wells in the palmyride area (syria) have been drilled through oligocene and eocene deposits. a detailed micropalaeontological investigation has been performed on the planktonic foraminiferal assemblage from drill cuttings. standard planktonic foraminiferal zones from p15 to p22 (e15 to o6) have been identified. the test morphology and diversity of the foraminiferal assemblage indicate a general cooling trend during the late eocene and oligocene. the specialized eocene forms (k-mode life strategy) such as turborotaliids, globigerinathekids and hantkeninids become extinct in the uppermost late eocene. the oligocene is characterized by the dominance of cooler, opportunistic planktonic foraminifera (r-mode life strategy), such as pseudohastigerinids, chiloguembelinids, globigerinids and tenuitellids. a very low number of benthic foraminifera in late eocene cuttings implies sedimentation in a deep, open sea environment. a gradual increase of the benthic foraminiferal proportion through the oligocene indicates shallowing of the sedimentary environment. 20 geologia croatica 59/1 planktonic foraminiferal morphology was performed on scanning electron microscope (sem). biostratigraphic interpretation was based on the standard planktonic foraminiferal biozonation (p zones) – berggren et al. (1995), and new planktonic foraminiferal biozonation (e and o zones) – berggren & pearson (2005) and pearson et al. (2006) (fig. 2). determination of the planktonic foraminiferal genera and species was based on bolli & saunders (1985), toumarkine & luterbacher (1985), spezzaferri (1994), iaccarino et al. (2005) and premoli silva & petrizzo (2006). the classification scheme used follows loeblich & tappan (1988). here, determination of planktonic foraminiferal biozones was based on the last occurrence (lo) of the index taxa to avoid possible mistakes as a result of mixing different foraminiferal associations in drill cuttings. the only exception is the boundary between zones o3 (p20) and o4 (p21a) which is defined by the first occurrence (fo) of globigerina angulisuturalis. because of the difficulty in identification of the first occurrence of the zonal marker, this boundary is an approximation. 3. geological setting the foraminiferal fauna has been studied from the hayan exploration block (fig. 1), which is situated in the palmyride area (central part of syria). the palmyrides are an inverted mesozoic rift basin (lučić & foršek, 2000; brew, 2001; brew et al., 2001). inversion began in the late cretaceous, but the majority of the inversion took place in the miocene (brew, 2001). syria can be divided into four major tectonic zones: the palmyride area, the abd el aziz–sinjar area, the euphrates fault system, and the dead sea fault system (brew, 2001; brew et al., 2001). the palmyrides are an intracontinental mountain fold belt which extend fig. 1 map of syria showing the location of the main tectonic zones (modified from brew, 2001). a circle represents the approximate location of the hayan exploration block. 21hernitz kučenjak et al.: planktonic foraminiferal biostratigraphy of the late eocene and oligocene... from the dead sea fault zone in the west, and join the euphrates fault system in the east (lučić & foršek, 2000; brew, 2001). the palmyrides extend 400 km approximately southwest to northeast across syria, and they are 100 km wide (lučić & foršek, 2000; brew, 2001). they can be further divided on the basis of topography and structure into the southwestern palmyrides (a fold and thrust belt) and the northeastern palmyrides – the bilas and bishri blocks. the jihar fault separates the two areas (brew, 2001). between the jihar fault and the short-wavelength folds of the southern palmyrides lies the low-relief al daww depression (lučić & foršek, 2000; brew, 2001), which is a 100 km long and 20 km wide inter-montaine basin. the hayan block is situated partly in the al daww depression and extends towards the bilas block. in the geological evolution of syria during the palaeogene, five main steps have been observed by krasheninnikov et al. (1996), which correspond to the following lithostratigraphic formations: calplanktonic foraminiferal zones berggren et al. (1995) berggren & pearson (2005) this worke p o c h m io c e n e o li g o c e n e la te la te e a r ly c h at ia n r u p e li a n p r ia b o n ia n e o c e n e e a r ly a q u it a n ia n a g e m1b m1a p22 o6 o6 o5 o5 o4 o4 o3 o3 o2 o2 o1 o1 e16 e16 e15 e15 e14 e14 b a p 21 p20 p19 p18 p15 p16 gt. kugleri / gq. dehiscens gd. primordius prz gl. ciperoensis prz gl. angulisuturalis / pg. opima s.s. isz gl. angulisuturalis / ch. cubensis crsz ch. cubensis pseudohastigerina spp. iz t. cerroazulensis iz t. cunialensis / cr. inflata crz gl. angulisuturalis / ch. cubensis crz gl. angulisuturalis / ch. cubensis pg. opima hoz gl. sellii prz t. ampliapertura iz t. ampliapertura hoz p. naguewichiensis hoz h. alabamensis hoz po. semiinvoluta iz g. semiinvoluta hoz g. semiinvoluta h. alabamensis g. index hoz g. index p. naguewichiensis t. ampliapertura gl. selliigl. sellii prz pg. opima gl. ciperoensis prz gl. ciperoensis not studied not studiedcrz p17 fig. 2 biostratigraphical zonation based on the planktonic foraminifera (after berggren & pearson, 2005); abbreviations: iz – interval zone, crz – concurrent-range zone, prz – partial-range zone, crsz – concurrent-range subzone, isz – interval subzone, hoz – highest-occurrence zone. 22 geologia croatica 59/1 careous clays and marls in the palaeocene and lower eocene; alternation of limestones and flints in the uppermost lower eocene; chalky and nummulitic limestones in the middle eocene; alternation of chalky and hard fine-grained limestones in the upper eocene and finally shallow biogenic limestones with terrigenous sediments at the top of the palaeogene formations, deposited during the oligocene. in the palmyrides, the oligocene marine sedimentation stopped at the neogene boundary, and the marine palaeogene is overlain by continental sediments or by unconformable and transgressive marine lower miocene deposits. 4. lithology in the studied exploration area, the middle eocene argillaceous limestones underlie the upper eocene deposits. these argillaceous limestones are greyish white to grey–greenish wackestone/packstones. they occasionally grade into calcareous marl, grey to brownish in colour. in places there are a few occurrences of grey quartz arenites. the upper eocene sedimentary rocks (biozones e14 to e16) are represented by greyish–white to grey–greenish argillaceous limestones of wackestone to wackestone/packstone types. occasional occurrences of marls have been found, but only in the jihar–4 well. the lower oligocene sediments are composed of light grey to grey marls, and white to grey–greenish argillaceous limestones of wackestone/packstone types. deposits of the upper oligocene consist of grey, sporadically sandy–clayey marls, with occurrences of very light grey fineto medium-grained quartz arenites. the upper oligocene deposits are overlain by the light grey sandstones of quartz wacke to quartz arenite type, and grey to brownish grey marls, possibly early miocene in age. according to the lithological characteristics of deposits and composition of the foraminiferal association (plankton/benthos ratio approx. 70:30), the upper eocene rocks were probably deposited in the open shelf environment, whereas the oligocene deposits (plankton/benthos ratio approx. 40:60) were accumulated in the outer to middle shelf environment. 5. planktonic foraminiferal biozonation of the late eocene to oligocene the frequency of planktonic foraminifera in the samples enables application of standard planktonic foraminiferal zonations (berggren et al., 1995; berggren & pearson, 2005; pearson et al., 2006 – fig. 2). zones e14 (p15) and e15/e16 (p16/p17) have been identified in the upper eocene. zones from o1 (p18) to o6 (p22) have been recognized in the oligocene sedimentary succession (fig. 3). zone e14 globigerinatheka semiinvoluta – berggren & pearson, 2005; pearson et al., 2006 (approx. = ponticulasphaera semiinvoluta zone p15 – berggren et al., 1995) intervals: jihar–1 (approx. 460 to 500 m), jihar–4 (approx. 635 to 675 m), jihar–5 (approx. 310 to 350 m). in the material studied, a very well preserved planktonic foraminiferal association has been presented. the lower boundary of this zone is defined by the extinction of all morozovellids and large acarininids and corresponds very well with previous investigations in the mediterranean and atlantic areas (premoli silva & boersma, 1988; premec-fućek et al., 1998; wade, 2004). only very small muricate species, such as acarinina medizzai toumarkine & bolli and acarinina collactea (finlay), persisted across the middle/late eocene boundary as in other mediterranean bioprovinces (premoli silva & boersma, 1988; premec-fućek et al., 1998). in the investigated wells, a. medizzai (pl. 1, figs. 1–4) and a.collactea became extinct at the end of zone e14. in that interval, the turborotalia lineage was represented by turborotalia cerroazulensis (howe & wallace), t. pomeroli (toumarkine & bolli), t. cocoaensis (cushman), and transitional forms between t. pomeroli and t. cerroazulensis (pl. 1, fig. 6). the microperforate species pseudohastigerina micra (cole) (pl. 1, fig. 5) was very frequent in the foraminiferal association of zone e14. furthermore, subbotina cryptomphala (glaesner), s. eocaena (guembel), s. angiporoides (hornibrook), s. yeguaensis (weinzierl & applin), globigerinatheka luterbacheri bolli, g. index (finlay), and hantkenina alabamensis cushman (pl. 1, figs. 8 & 9) have been identified. as the zone marker, globigerinatheka semiinvoluta (keijzer), in the analysed samples has not been presented, the top of zone e14 is defined approximately by the last occurrence of the acarinina medizzai (premoli silva & petrizzo, 2006; pearson et al., 2006). zone e15 globigerinatheka index – berggren & pearson, 2005; (approx. upper part of ponticulasphaera semiinvoluta zone p15 and lower part of turborotalia cunialensis/ cribrohantkenina inflata zone p16 – berggren et al., 1995) and zone e16 hantkenina alabamensis – berggren & pearson, 2005 (approx. upper part of turborotalia cunialensis/ cribrohantkenina inflata zone p16 and globigerina gortanii gortanii – turborotalia centralis p17 – berggren et al., 1995) intervals: jihar–1 (410 to approx. 460m), jihar–4 (595 to approx. 635 m), jihar–5 (270 to approx. 310 m). separation of zones e15 and e16 has not been possible because the index taxon globigerinatheka index (finlay) has only been found in the jihar–1 well. 23hernitz kučenjak et al.: planktonic foraminiferal biostratigraphy of the late eocene and oligocene... ji h a r -1 ji h a r -4 ji h a r -5 10 0 20 0 30 0 40 0 60 0 50 0 o 6 94 97 m 31 67 m o 5 o 4 o 3 o 2 o 1 e 15 /1 6 e 14 li m e s to n e a r g il la c e o u s m a r l c la y e y m a r l s a n d y c la y e y m a r l le g e n dsw n e se n w large acarininids and morozovellids acarinina medizzai turborotalia cerroazulensis group turborotalia ampliapertura turborotalia ampliapertura globigerina angulisuturalis chiloguembelina cubensis paragloborotalia opima streptochilus pristinum globigerinoides primordius paragloborotalia opima cribrohantkenina inflata hantkenina alabamensis pseudohastigerina naguewichiensis fi r s t o c c u r e n c e la s t o c c u r e n c e p r e s u m e d b o u n d a r y 0 m fig. 3 schematic profile of the exploration wells with planktonic foraminiferal biozones and last occurrence (lo) and approx. first occurrence (fo) of index taxa. 24 geologia croatica 59/1 the planktonic foraminiferal assemblage of these intervals consists of a few representatives of the turborotalia lineage which do not extend beyond the eocene/oligocene boundary – turborotalia cerroazulensis (howe & wallace) (pl. 2, figs. 4–6), t. pomeroli (pl. 2, figs. 8 & 9), and t. cocoaensis (cushman) (pl. 2, figs. 1–3), whereas species including t. increbescens (bandy) and t. ampliapertura (bolli) persist into the early oligocene. cribrohantkenina inflata (howe) (pl. 2, fig. 7), is a species with a very short stratigraphic range, from the upper part of zone e14 to the end of e16 (pearson et al., 2006), and has only been observed in the jihar–5 well. small microperforate species pseudohastigerina micra (cole), p. naguewichiensis (myatliuk), biserial chiloguembelina cubensis (palmer) and tenuiteliids in the 63–125 µm size fraction have also been observed. in the late eocene assemblage, the coexistence of subbotina cryptomphala (glaesner), s. yeguaensis (weinzierl & applin), s. linaperta (finlay), s. corpulenta (subbotina) (pl. 1, fig. 7), catapsydrax dissimilis (cushman & bermudez), c. unicavus bolli (pl. 1, fig. 10), globigerina officinalis subbotina, globigerinatheka luterbacheri, bolli and dentoglobigerina galavisi (bermudez) (pl. 1, figs. 11 & 12) have been observed. zone o1 pseudohastigerina naguewichiensis – berggren & pearson, 2005 (approx. chiloguembelina cubensis – pseudohastigerina sp. p18 – berggren et al., 1995) intervals: jihar–1 (390–410 m), jihar–4 (555–595 m), jihar–5 (220–270 m). the eocene/oligocene boundary is marked by the faunal overturn which is indicated by the extinction of specialized forms, such as the turborotalia cerroazulensis s.s. group, globigerinathekids and hantkeninids (keller, 1983; boersma & premoli silva, 1991). in the earliest rupelian, the planktonic foraminiferal assemblage comprises mostly round-chambered forms such as high and low spired subbotinids, catapsydracids, dentoglobigerinids, microperforate tenuitellids, pseudohastigerinids and chiloguembelinids (iaccarino et al., 2005). the assemblage of this zone in the investigated wells is characterized by the occurrence of globigerinids and dentoglobigerinids such as “globigerina” rohri (bolli) (pl. 3, fig. 7), “globigerina” venezuelana hedberg, “globigerina” euapertura jenkins, dentoglobigerina globularis (bermudez) (pl. 3, fig. 4) and d. baroemoensis (le roy) (pl. 3, figs. 5 & 6). turborotalia increbescens (bandy) (pl. 2, figs. 11 & 12) and t. ampliapertura (bolli) (pl. 2, fig. 10) are the representatives of the turborotalia lineage persisting across the eocene/oligocene boundary. small microperforate species in the samples of this zone are pseudohastigerina naguewichiensis (myatliuk) (pl. 3, figs. 2 & 3), chiloguembelina cubensis (palmer) and tenuitelids. species which range from the middle eocene, paragloborotalia nana (bolli) (pl. 3, fig. 1) are also represented. the top of zone o1 is marked by the extinction of pseudohastigerina naguewichiensis (berggren & pearson, 2005). in the investigated wells the last occurrence of p. naguewichiensis has been observed in the following samples: jihar–1 – 390– 400 m, jihar–4 – 555–575 m, jihar–5 – 220–230 m. zone o2 turborotalia ampliapertura – berggren & pearson, 2005 (“turborotalia ampliapertura” p19 – berggren et al., 1995) intervals: jihar–1 (360–390 m), jihar–4 (515–555 m), jihar–5 (210–220 m). the base of zone o2 is defined by the last appearance datum of pseudohastigerina naguewichiensis. the planktonic foraminiferal association from zone o2 consists of large forms such as “globigerina” tapuriensis blow & banner, “globigerina” venezuelana hedberg, catapsydrax martini (blow & banner), “globigerina” sp. and dentoglobigerina sp. (pl. 3, figs. 11 & 12). representatives of the microperforate planktonic foraminifera are still present – cassigerinella chipolensis (cushman & ponton), chiloguembelina cubensis (palmer) and tenuitellinata sp. moreover, in samples from the palmyra region turborotalia ampliapertura (bolli) (pl. 3, figs. 8 & 9), turborotalia increbescens (bandy) (pl. 3, fig. 10), globoturborotalita ouachitaensis (howe & wallace) and globigerina praebulloides blow have been observed. the top of zone o2 is defined by the last appearance datum of turborotalia ampliapertura (berggren et al., 1995; berggren & pearson, 2005). in the jihar–1 well the last occurrence of t. ampliapertura is in the 360–370 m sample, in jihar–4 at 515–535 m, and in jihar–5 at the 210–220 m samples. zone o3 globigerina sellii – berggren & pearson, 2005 (globigerina sellii p20 – berggren et al., 1995) intervals: jihar–1 (approx. 320–360 m), jihar–4 (approx. 495–515 m), jihar–5 (approx. 200–210 m). the material of this zone is characterised by the frequent occurrence of small microperforate planktonic foraminifera chiloguembelina cubensis (palmer), cassigerinella chipolensis (cushman & ponton), tenuitellinata angustiumbilicata (bolli) (pl. 4, figs. 2 & 3) and tenuitella gemma (jenkins) (pl. 4, fig. 6). further, in the planktonic foraminiferal association, larger forms such as “globigerina” tripartita koch (pl. 4, fig. 4), “globigerina” venezuelana hedberg (pl. 4, fig. 5), “globigerina” sp., globorotaloides sp. (pl. 4, fig. 1), dentoglobigerina sp. and paragloborotalia opima (bolli) are determined. also small globigerinids, globigerina praebulloides blow and globigerina praebulloides occlusa blow & banner, are represented. 25hernitz kučenjak et al.: planktonic foraminiferal biostratigraphy of the late eocene and oligocene... due to difficulties in identifying the first appearance datum of the index species in the material from drill cuttings, the top of the zone is established approximately by the first occurrence of globigerina angulisuturalis (berggren et al., 1995; berggren & pearson, 2005). first occurrence of g. angulisuturalis in the investigated syrian wells has been recognized in the following samples: jihar–1 – 200–210 m, jihar–4 – 495–515 m and jihar–5 – 320–330 m. zone o4 globigerina angulisuturalis/ chiloguembelina cubensis – berggren & pearson, 2005 (globigerina angulisuturalis/ chiloguembelina cubensis p21a – berggren et al., 1995) intervals: jihar–1 (280 to approx. 320 m), jihar–4 (475 to approx. 495 m), jihar–5 (190 to approx. 200 m). the planktonic foraminiferal association of this zone is very well preserved and diverse. small globigerinids globigerina angulisuturalis (bolli) (pl. 4, figs. 7–9), g. ciperoensis (bolli), g. ouachitaensis (howe & wallace) and g. praebulloides blow are very frequent in zone o4 samples. microperforate species chiloguembelina cubensis (palmer) (pl. 4, figs. 11 & 12), cassigerinella chipolensis (cushman & ponton), and tenuitella gemma (jenkins) are also documented from this interval, as well as larger forms catapsydrax martini (blow & banner), “globigerina” tapuriensis blow & banner, “globigerina” venezuelana hedberg (pl. 4, fig. 10), paragloborotalia opima (bolli), dentoglobigerina sp. and globorotaloides sp. the top of zone o4 is marked by extinction of the microperforate biserial planktonic foraminifera chiloguembelina cubensis (berggren et al., 1995; berggren & pearson, 2005). in the jihar–1 well the lo of c. cubensis has been noticed in a sample at 280–290 m, in jihar–4 at 475–495 m and in jihar–5 at 190–200 m sample. zone o5 paragloborotalia opima – berggren & pearson, 2005 (globigerina angulisuturalis/ paragloborotalia opima opima p21b – berggren et al., 1995) intervals: jihar–1 (250–280 m), jihar–4 (435–475 m), jihar–5 (170–190 m). the planktonic foraminiferal association in the lower chatian consists of small spinose globigerinids globigerina angulisuturalis (bolli), globigerina ciperoensis (bolli) (pl. 5, fig. 1), g. officinalis subbotina and g. praebullides blow. in addition, paragloborotalia opima (bolli) (pl. 5, figs. 5 & 6), p. nana (bolli) (pl. 5, figs. 8 & 9), and “globigerina” sp. are also determined. microperforate species cassigerinella chipolensis (cushman & ponton) (pl. 5, figs. 2 & 3), tenuitellinata angustiumbilicata (bolli), and tenuitellinata sp. in the 63 µm sieve fraction have been observed. the top of zone o5 is marked by the last occurrence of paragloborotalia opima, which has been recognized at 250–260 m in jihar–1, at 435–455 m in jihar–4 and at 170–180 m in jihar–5. zone o6 globigerina ciperoensis – berggren & pearson, 2005 (globigerina ciperoensis p22 – berggren et al., 1995) intervals: jihar–1 (approx. 220–250 m), jihar–4 (approx. 415–435 m), jihar–5 (approx. 160–170 m). the assemblage of this zone is characterised by the occurrence of globigerina angulisuturalis (bolli) (pl. 5, figs. 11 & 12), g. ciperoensis (bolli) (pl. 5, figs. 4 & 7), g. praebulloides blow, dentoglobigerina baroemoensis (le roy), and globigerina sp. in the jihar–5 well, a very rare microperforate biserial species streptohilus pristinum broennimann & resig (pl. 5, fig. 10) has been found. furthermore, microperforate tenuitellinata angustiumbilicata (bolli) and tenuitella sp. have also been determined. in this zone, the first appearance of globigerinoides primordius blow & banner was observed. the boundary between the oligocene and miocene is marked by the first occurrence of globorotalia kugleri s.s. (berggren et al., 1995; berggren & pearson, 2005). this planktonic foraminiferal species has not been found in samples from exploration wells, and the boundary of this zone is only approximately established. the following facts aided the establishment of the eocene/oligocene boundary: first, changes were evident in the foraminiferal association, i.e. an increased abundance of benthic foraminifera (neoeponides schreibersi (giannini & tavani), spiroplectinella carrinata (d’orbigny), lenticulina vortex (fichtel & moll), heterolepa sp., gyroidina sp., cibicidoides sp., marginulinopsis sp., dentalina sp.), and second, near the boundary, the oligocene species globigerina ciperoensis disappeared. furthermore, correlation with oligocene sedimentary rocks in the wider syrian regions was also helpful. krasheninnikov et al. (1996) reported the regressive nature of the oligocene deposits. in the palmyrids the oligocene marine sedimentary regime terminated at the neogene boundary, and the marine palaeogene is unconformably and transgressively overlain by marine lower miocene deposits. 6. palaeoecology and climatic changes planktonic foraminifera have great potential in palaeoecological studies (murray, 1991a). these tiny monocellular organisms with calcite shells are distributed throughout the world seas and oceans, from the polar water masses to the equator, and have different depth preferences of habitat in a stratified water column (hemleben et al., 1989; murray, 1991a; pearson, 1998). biotic and abiotic factors affect their diversity, morphology, and distribution. abiotic 26 geologia croatica 59/1 factors which may influence the distribution of planktonic foraminifera are temperature, salinity, water density, nutrients, light, turbidity, and currents (hallock, 1987; hemleben et al., 1989; murray, 1991a). biotic factors include food supply, symbiotic relationships, productivity and interfaunal relationships (bé, 1982; murray, 1991a; hallock et al., 1991). planktonic foraminifera are, therefore, very useful in palaeooceanological and palaeoclimatological studies. much of the world oceans in tropical and subtropical areas are well stratified and oligotrophic. the ecology of the various species in these environments is closely related to their preferred niche in the water column (hemleben et al., 1989; murray, 1991a; pearson, 1998; coxall et al., 2000; wade, 2004; sexton et al., 2006). in general, planktonic foraminiferal species live in two preferred depth habitats: (1) shallow-dwelling planktonic foraminifera tend to have thinner or more porous, less dense shells, more globular chambers and they are often spinose (pearson, 1998). the function of spines is to carry external cytoplasm with symbionts and to prevent escape of prey (hemleben et al., 1989; pearson, 1998). shallow-dwelling species have their primary aperture usually in the central position at the umbilical side of the test (pearson, 1998). some of them have multiple supplementary apertures. isotope analyses of the planktonic foraminiferal calcite shells provide one of the most important insights into oceanographic changes during earth history. stable isotope studies of the surface dwelling planktonic foraminifera usually indicate the lightest δ18o and heaviest δ13c values in modern as well as in fossil planktonic foraminiferal shells. (2) the majority of modern deeper-dwelling forms and some ancient examples tend to have more angular and flattened chambers. the position of a primary aperture is more extraumbilical and there are no supplementary apertures (pearson, 1998). detailed isotope analyses from two species turborotalia pomeroli and t. cerroazulensis from the adriatic sea indicate a thermocline habitat for the turborotalia cerroazulensis group (premec fućek & pearson, 2006). species within the genera subbotina and catapsydrax are interpreted as having occupied a relatively deep thermocline habitat (pearson et al., 1993, 2001; sexton et al., 2006). late eocene the upper eocene succession of the syrian wells contains a rich and diverse planktonic foraminiferal association. muricate forms including acarinina medizzai and a. collactea have only been represented in zone e14. previous isotope investigations of acarininids show the lightest δ18o values suggesting a habitat in the uppermost part of the water column. most positive δ13c values indicate a relationship with algal simbionts (shackleton et al., 1985; pearson et al., 1993; d’hondt et al., 1994; wade, 2004; sexton et al., 2006). in the analysed samples, few species of globigerinatheka in zone e14 and zone e15/e16 have been found. the eocene genus globigerinatheka includes spinose forms (premec fućek et al., 1998), as in many modern species in tropical and subtropical regions (hemleben et al., 1989), possessing algal symbionts. they are limited to the shallow, mixed layer of the oceans and seas because of the photosynthetic requirements of their algae (bé, 1982; murray, 1991a). these aforementioned species indicate a subtropical to warm climatic bioprovince for the east mediterranean area during the late eocene. representatives of the non-spinose genus turborotalia (t. pomeroli, t. cerroazulensis and t. cocoaensis) occupy an upper thermocline habitat (pearson et al., 2001; wade, 2004; premec fućek & pearson, 2006). stable isotope records of the turborotalid tests show relatively light δ13c signals suggesting that they have no association with algal symbionts (premec fućek & pearson, 2006). during the late eocene, a few extinctions occurred. acarinina medizzai and acarinina collactea became extinct at the end of zone e14. due to the absence of the zonal marker globigerinatheka semiinvoluta, the last appearance of these two species has been used to approximately define the e14/e15 boundary (see distribution range of a. medizzai in pearson et al., 2006). globigerinathekids decline in abundance and diversity and at the lower part of the e15/e16 (p16/p17) zone become extinct. in berggren & pearson (2005), the lo of globigerinatheka mark the top of the zone e15. the most dramatic extinction event happened close to the eocene/oligocene boundary when the last specimens of turborotalia cerroazulensis (howe & wallace), t. pomeroli (toumarkine & bolli) and t. cocoaensis (cushman) disappeared. also cribrohantkenina inflata (howe) disappeared almost simultaneously, while the species turborotalia increbescens (bandy) and turborotalia ampliapertura (bolli) persisted in the early oligocene. in the same horizons, typical palaeogene opportunistic foraminifera including biserial heterohelicids, low spired subbotinids, and tenuitellids (hallock et al., 1991) became more and more frequent in assemblages. eocene/oligocene boundary the significant changes of planktonic foraminiferal assemblages indicate a general cooling trend and eutrophication of the euphotic zone during late eocene and oligocene times (keller, 1983; boersma & premoli silva, 1991). a highly diversified, subtropical to warm fauna, where a k-mode life strategy predominated, was gradually replaced by less diverse assemblages dominated by r-strategy taxa indicating cooler waters. the eocene/oligocene boundary is marked by the extinction of hantkenina. the climate event (oi–1) occurs 200 kyr after the boundary (wade & pälike, 2004) and is the result of the ocean temperature drop, the formation of antarctic ice sheets and the development of heavy cold water circulation locally 27hernitz kučenjak et al.: planktonic foraminiferal biostratigraphy of the late eocene and oligocene... on the bottom of the ocean (cavelier et al., 1981; zachos et al., 1996, 2001; mackensen, 2004; wade & pälike, 2004). the results of cooling have been a shallowing of thermocline depth and reduction in the abundance of shallowand warm-water species (spezzaferri et al., 2002). the faunal overturn is indicated by the extinction of specialised eocene forms (k-strategists), such as turborotalids, globigerinathekids, hantkeninids, and their replacement by generalised globigerinid form species. in addition, the decrease in the size of specimens is remarkable, as well as increased abundances of the opportunistic taxa and cool water indices, increased numbers of the non spinose, deeper dwelling forms, and reduction in diversity (premoli silva & boersma, 1988; boersma & premoli silva, 1991). oligocene the investigated pseudohastigerinids, chiloguembelinids and tenuitelids within the planktonic foraminiferal association suggest cooler water conditions in the early oligocene (spezzaferri & premoli silva, 1991). pseudohastigerinids did not persist into zone o2. the extinction of chiloguembelina cubensis marks the top of zone o4. species of the globigerina ciperoensis group (g. ciperoensis, g. angulisuturalis) were best adapted to the late oligocene environmental conditions. they possess a small lowered trochospiral test with a cancellate and spinose wall texture. these species are abundant at low latitudes outside upwelling areas, and they seem to prefer higher salinity water conditions (spezzaferri & premoli silva, 1991; spezzaferri, 1994). in zone o6, very tiny microperforate and the rare species streptochilus pristinum (pl. 6, fig. 10) have been found. furthermore, globigerinoides primordius has its first occurrence in the planktonic foraminiferal assemblage of the late oligocene. this species with a smooth and spinose wall texture indicates a shift to warmer climatic conditions in the late oligocene. in the late eocene, predominance of the planktonic foraminifera, i.e. very low numbers of benthic foraminifera (cibicidoides, lenticulina, marginulinopsis, heterolepa, tritaxia, anomalinoides) implies sedimentation in a deeper, open-sea environment (van der zwaan et al., 1990; murray, 1991b). a gradual increase of the benthic foraminiferal proportions (cibicidoides, lenticulina, spiroplectinella, gyroidina, neoeponides, marginulinopsis, heterolepa, stilostomella, dentalina) upwards through the oligocene interval indicates shallowing of the sedimentary environment (van der zwaan et al., 1990; murray, 1991b). 7. conclusion the palmyride area in syria contains a succession of upper eocene to upper oligocene deposits. on the basis of a rich planktonic foraminiferal association, biozones from e14 (p15) to o6 (p22) have been identified. biostratigraphic zonal boundaries are determined on the last occurrence of the index taxa. significant changes marked by the extinction of muricate forms, except for small acarinids, have occurred at the beginning of zone e14. during the late eocene, the number of warm shallow dwelling species decreases, thus indicating the onset of global cooling, which culminated in the earliest oligocene. this significant climatic change is well documented by the planktonic foraminiferal assemblage collected from the studied area. a faunal overturn is indicated by the extinction of specialized eocene forms (k-mode life strategy), such as turborotalids, globigerinathekids, hantkeninids and their replacement by cooler, opportunistic globigerinid forms. the early oligocene, as a period of glacial episodes, is characterised by dominance of the r-strategist planktonic foraminiferal species, such as pseudohastigerinids, chiloguembelinids, globigerinids, and tenuitelids. the planktonic foraminiferal association of the late oligocene shows a trend towards warming, due to the presence of specimens from the globigerina ciperoensis group and globigerinoides primordius. a very low number of benthic foraminifera in the association imply sedimentation in the deep, open-sea environment during the late eocene. through the oligocene, the proportion of benthic foraminifera in the assemblage gradually increased, thus indicating the shallowing of the sedimentary environment, connected with the global sea level decrease and regional tectonic events. acknowledgements we thank members of the palaeogene planktonic foraminiferal working group for discussion on taxonomy and biostratigraphy of palaeogene planktonic foraminifera. we thank bridget wade for valuable comments and constructive review of this manuscript. we also thank vlasta ćosović for helpful discussion and critical review. this research was supported by ina– industrija nafte d.d. zagreb, who also provided the samples from the syrian wells. 8. references bé, a.w.h. (1982): biology of planktonic foraminifera.– in: buzas, m.a. & sen gupta, b.k. (eds.): notes for a short course, 219, university of tennessee, dep. geol. sci., studies in geology, new orleans, 51–89. berggren, w.a. & miller, k.g. (1988): paleogene tropical planktonic foraminiferal biostratigraphy and magnetobiochronology.– micropaleontology, 34/4, 362–380. 28 geologia croatica 59/1 berggren, w.a. & pearson, p.n. (2005): a revised tropical to subtropical paleogene planktonic foraminifera zonation.– journal of foraminiferal research, 35/4, 279– 298. berggren, w.a., kent, d.v., swisher c.c. & aubry, m. (1995): a revised cenozoic geochronology and chronostratigraphy.– in: berggren, w.a., kent, d.v., aubry, m. & hardenbol, j. (eds.): geochronology, time scales and global stratigraphic correlation. special publication of society for sedimentary geology. tulsa, 129–212. blow, w.h. (1979): the cainozoic globigerinida, vol. 3.– e. j. brill, leiden, 1452 p. boersma, a. (1988): foraminifera.– in: haq, b.u. & boersma, a. (eds.): introduction to marine micropaleontology. elsevier science, singapore, 19–78. boersma, a. & premoli silva, i. (1991): distribution of paleogene planktonic foraminifera – analogies with the recent?– palaeogeography, palaeoclimatology, palaeoecology, 83, 29–48. bolli, h.m. (1957): planktonic foraminifera from the eocene navet formation and san fernando formations in trinidad, b. w. i.– in: loeblich, a.r.jr., tappan, h., beckmann, j.p., bolli, h.m., montenaro gallitelli, e. & troelsen, j.c. (eds.): studies in foraminifera. bulletin of the united states national museum, 215, 155–172. bolli, h.m. & saunders, j.b. (1985): oligocene to holocene low latitude planktic foraminifera.– in: bolli, h.m., saunders, j.b. & perch-nielsen, k. (eds.): plankton stratigraphy. cambridge university press, cambridge, 155–262. brew, g.e. (2001): tectonic evolution of syria interpreted from integrated geophysical and geological analysis.– phd thesis, cornell university, ithaca, new york, 323 p. brew, g., barazangi, m., al-maleh, a.k. & sawaf, t. (2001): tectonic and geologic evolution of syria.– geoarabia, 6/4, 573–616. cavelier, c., chateauneuf, j., pomerol, c., rabussier, d., renard, m. & vergnaud-grazzini, c. (1981): the geological events at the eocene/oligocene boundary.– palaeogeography, palaeoclimatology, palaeoecology, 36, 223–248. coxall, h.k., pearson, p.n., shackleton, n.j. & hall, m.a. (2000): hantkeninid depth adaptation: an evolving life strategy in a changing ocean.– geology, 28/1, 87–90. d’hondt, s., zachos, j.c. & schultz, g. (1994): stable isotops signals and photosymbiosis in late paleocene planktic foraminifera.– paleobiology, 20/3, 391–406. hallock, p. (1987): fluctuations in the trophic resource continuum: a factor in global diversity cycles.– paleoceanography, 215, 457–471. hallock, p., premoli silva, i. & boersma, a. (1991): similarities between planktonic and larger foraminiferal evolutionary trends through paleogene paleoceanographic changes.– palaeogeography, palaeoclimatology, palaeoecology, 83, 49–64. hemleben, c., spindler, m. & anderson, o.r. (1989): modern planktonic foraminifera.– springer-verlag, new york, 363 p. hernitz kučenjak, m., premec fućek, v. & slavković, r. (2005): planktonic foraminifera turnover at the eocene/oligocene boundary (palmyra region, syria).– in: velić, i., vlahović, i. & biondić, r. (eds.): 3. hrvatski geološki kongres, opatija, 2005. knjiga sažetaka, zagreb, 55–56. iaccarino, s.m., premoli silva, i., biolzi, m., foresi, m., lirer, f. & petrizzo, m.r. (2005): practical manual of oligocene to middle miocene planktonic foraminifera.– international school on planktonic foraminifera, universita degli studi di perugia, università degli studi di parma, universita degli studi di milano, perugia–parma–milano, 124 p. keller, g. (1983): biochronology and paleoclimatic implications of middle eocene to oligocene planktonic foraminiferal faunas.– marine micropaleontology, 7, 463–486. krasheninnikov, v.a., golovin, d.i. & mouravyov, v.i. (1996): the paleogene of syria – stratigraphy, lithology, geochronology. – geologisches jahrbuch reiche b, b 86, 136 p. loeblich, a.r.jr. & tappan, h. (1988): foraminiferal genera and their classification.– van nostrand and reinhold company, new york, 2. vols., 970 p. lučić, d. & foršek, g. (2000): palmyride evolution: geologic, stratigraphic and structural overview (central syria).– in: vlahović, i. & biondić, r. (eds.): 2. hrvatski geološki kongres, cavtat – dubrovnik, 17– 20.05.2000., zbornik radova, institut za geološka istraživanja, 311–316. mackensen, a. (2004): changing southern ocean palaeocirculation and effects on global climate.– antarctic science, 16/4, 369–386. murray, j.w. (1991a): ecology and distribution of planktonic foraminifera.– in: lee, j.j. & anderson, o.r. (eds.): biology of foraminifera. academic press, london, 255–285. murray, j.w. (1991b): ecology and paleoecology of benthic foraminifera.– longman scientific & technical, essex, 397 p. pearson, p.n. (1998): stable isotopes and the study of evolution in planktonic foraminifera.– in: norris, r.d. & corfield, r.m. (eds.): isotope paleobiology and paleoecology. paleontol. soc. papers, 4, 138–178. pearson, p.n., shackleton, n.j. & hall, m.a. (1993): stable isotope paleoecology of middle eocene planktonic foraminifera and multi-species isotope stratigraphy, dsdp site 523, south atlantic.– journal of foraminiferal research, 23/2, 123–140. pearson, p.n., ditchfield, p.w., signano, j., harcourt-brown, k.g., nicholas, c.j., olsson, r.k., shackleton, n.j. & hall, m.a. (2001): warm tropical sea surface temperatures in the late cretaceous and eocene epochs.– nature, 413, 481–487. pearson, p.n., olsson, r.k., huber, b.t., hemleben, c. & berggren, w.a. (2006): atlas of eocene planktonic foraminifera.– the cushman foundation for foraminiferal research, special paper, 41, in press. 29hernitz kučenjak et al.: planktonic foraminiferal biostratigraphy of the late eocene and oligocene... premec-fućek, v., babić, lj., bajraktarević, z. & gušić, i. (1998): planktonic foraminiferal biostratigraphy of the middle to upper eocene succesion in the north adriatic sea.– dela–opera sazu 4. razr., 34/2, 255–271. premec-fućek, v. & pearson, p.n. (2006): isotope records from turborotalia cerroazulensis and turborotalia pomeroli near the middle/late eocene boundary (north adriatic sea, croatia).– forams 2006, abstract book, natal (in press). premoli silva, i. & boersma, a. (1988): atlantic eocene planktonic foraminiferal historical biogeography and paleohydrogeographic indices.– palaeogeography, palaeoclimatology, palaeoecology, 67, 315–356. premoli silva, i. & petrizzo, m.r. (2006): practical manual of eocene planktonic foraminifera.– international school on planktonic foraminifera, universita degli studi di perugia, universita degli studi di milano. perugia, 248 p. sexton, ph.f., wilson, p.a. & pearson, p.n. (2006): palaeoecology of late middle eocene planktic foraminifera and evolutionary implications.– marine micropaleontology, 60/1–6, 1–15. shackleton, n.j. corfield, r.m. & hall, m.a. (1985): stable isotope data and the ontogeny of paleocene planktonic foraminifera.– journal of foraminiferal research, 15/4, 321–336. spezzaferri, s. (1994): planktonic foraminiferal biostratigraphy and taxonomy of the oligocene and lower miocene in the oceanic record. an overview.– paleontographica italica, 81, 1–187. spezzaferri, s. & premoli silva, i. (1991): oligocene planktonic foraminiferal biostratigraphy and paleoclimatic interpretation from hole 538a, dsdp leg 77, gulf of mexico.– palaeogeography, palaeoclimatology, palaeoecology, 83, 217–236. spezzaferri, s., basso, d. & coccioni, r. (2002): late eocene planktonic foraminiferal response to an extraterrestrial impact at massignano gssp (northeastern appennines, italy).– journal of foraminiferal research, 32/2, 188–199. stainforth, r.m., lamb, j.l., luterbacher, h., beard, j.h. & jeffords, r.m. (1975): cenozoic planktonic foraminiferal zonation and characteristics of index forms.– the university of kansas paleontological contributions, 62, 425 p. subbotina, n.n. (1947): foraminifery datskikh i paleogenovykh otlozhenii severnogo kavkaza [foraminifera of dacian and palaeogene deposits of northern caucasus – in russian].– in: mikrofauna neftyanykh mestorozhdenii kavkata, emby i srednei azii. vesesoyuznyi nauchnoissledovatel’skii geollogo–razvedochni neftyanoi institut (vnigri), trudy, lengostoptekhizdat, 39–160. toumarkine, m. & luterbacher, h. (1985): paleocene and eocene planktic foraminifera.– in: bolli, h.m., saunders, j.b. & perch-nielsen, k. (eds.): plankton stratigraphy. cambridge university press, cambridge, 87–154. van der zwaan, g.j., jorissen, f.j. & de stigter, h.c. (1990): the depth dependency of planktonic/benthic foraminiferal ratios: constraints and applications.– marine geology, 95, 1–16. wade, b.s. (2004): planktonic foraminiferal biostratigraphy and mechanisms in the extinction of morozovella in the late middle eocene.– marine micropaleontology, 51, 23–38. wade, b.s. & pälike, h. (2004): oligocene climate dynamics.– paleoceanography, 19, 1–16. zachos, j.c., quinn, t.m. & salamy, k.a. (1996): high-resolution (104 years) deep-sea foraminiferal stable isotope records of the eocene–oligocene climate transition.– paleoceanography, 11/3, 251–266. zachos, j., pagani, m., sloan, l., thomas, e. & billups, k. (2001): trends, rhythms, and aberrations in global climate 65 ma to present.– science, 292, 686–693. manuscript received april 12, 2006. revised manuscript accepted june 9, 2006. 30 geologia croatica 59/1 plate 1 fig. 1 acarinina medizzai (toumarkine & bolli), jihar–1, interval 460–470 m, zone e14. fig. 2 acarinina medizzai (toumarkine & bolli), jihar–4, interval 635–655 m, zone e14. fig. 3 acarinina medizzai (toumarkine & bolli), detail of the wall texture, jihar–4, interval 635–655 m, zone e14. fig. 4 acarinina cf. medizzai (toumarkine & bolli), jihar–4, interval 635–655 m, zone e14. fig. 5 pseudohastigerina micra (cole), jihar–1, interval 460–470 m, zone e14. fig. 6 turborotalia pomeroli (toumarkine & bolli) – turborotalia ceroazulensis (howe & wallace) transition form, jihar–1, interval 460–470 m, zone e14. fig. 7 subbotina corpulenta (subbotina), jihar–5, interval 280–290 m, zone e15/16. fig. 8 hantkenina cf. alabamensis cushman, jihar–5, interval 310–320 m, zone e14. fig. 9 hantkenina cf. alabamensis cushman, detail of the wall texture, jihar–5, interval 310–320 m, zone e14. fig. 10 catapsydrax unicavus bolli, jihar–1, interval 410–420 m, zone e15/16. fig. 11 dentoglobigerina galavisi (bermudez), jihar–5, interval 280–290 m, zone e15/16. fig. 12 dentoglobigerina galavisi (bermudez), detail of the aperture and wall texture, jihar–5, interval 280– 290 m, zone e15/16. 31 1 2 3 4 5 6 7 8 9 10 11 12 hernitz kučenjak et al. plate 1 32 geologia croatica 59/1 plate 2 fig. 1 turborotalia cocoaensis (cushman), jihar–5, interval 280–290 m, zone e15/16. fig. 2. turborotalia cocoaensis (cushman), jihar–5, interval 280–290 m, zone e15/16. fig. 3 turborotalia cocoaensis (cushman), detail of the wall texture, jihar–5, interval 280–290 m, zone e15/ 16. fig. 4 turborotalia cerroazulensis (cushman), jihar–5, interval 280–290 m, zone e15/16. fig. 5 turborotalia cerroazulensis (cushman), jihar–5, interval 280–290 m, zone e15/16. fig. 6 turborotalia cerroazulensis (cushman), detail of the wall texture, jihar–5, interval 280–290 m, zone e15/16. fig. 7 cribrohantkenina inflata (howe), jihar–5, interval 280–290 m, zone e15/16. fig. 8 turborotalia pomeroli (toumarkine & bolli), jihar–5, interval 280–290 m, zone e15/16. fig. 9 turborotalia pomeroli (toumarkine & bolli), detail of the wall texture, jihar–5, interval 280–290 m, zone e15/16. fig. 10 turborotalia ampliapertura (bolli), jihar–5, interval 260–270 m, zone o1. fig. 11 turborotalia increbescens (bandy) jihar–5, interval 260–270 m, zone o1. fig. 12 turborotalia increbescens (bandy) detail of the wall texture, jihar–5, interval 260–270 m, zone o1. 33 1 2 3 4 5 6 7 8 9 10 11 12 hernitz kučenjak et al. plate 2 34 geologia croatica 59/1 plate 3 fig. 1 paragloborotalia nana (bolli), jihar–5, interval 260–270 m, zone o1. fig. 2 pseudohastigerina naguewichiensis (myatliuk), jihar–5, interval 220–230 m, zone o1. fig. 3 pseudohastigerina naguewichiensis (myatliuk), detail of the wall texture, jihar–5, interval 220–230 m, zone o1. fig. 4 dentoglobigerina globularis (bermudez), jihar–5, interval 260–270 m, zone o1. fig. 5 dentoglobigerina baroemoensis (le roy), jihar–5, interval 260–270 m, zone o1. fig. 6 dentoglobigerina baroemoensis (le roy), detail of the wall texture, jihar–5, interval 260–270 m, zone o1. fig. 7 “globigerina“ rohri bolli, jihar–5, interval 250–260 m, zone o1. fig. 8 turborotalia ampliapertura (bolli), jihar–5, interval 210–220 m, zone o2. fig. 9 turborotalia ampliapertura (bolli), detail of the wall texture, jihar–5, interval 210–220 m, zone o2. fig. 10 turborotalia increbescens (bandy), jihar–4, interval 515–535 m, zone o2. fig. 11 dentoglobigerina sp., jihar–5, interval 210–220 m, zone o2. fig. 12 dentoglobigerina sp., detail of the aperture and wall texture, jihar–5, interval 210–220 m, zone o2. 35 1 2 3 4 5 6 7 8 9 10 11 12 hernitz kučenjak et al. plate 3 36 geologia croatica 59/1 plate 4 fig. 1 globorotaloides sp., jihar–1, interval 350–360 m, zone o3. fig. 2 tenuitellinata angustiumbilicata (bolli), jihar–1, interval 350–360 m, zone o3. fig. 3 tenuitellinata angustiumbilicata (bolli), detail of the wall texture, jihar–1, interval 350–360 m, zone o3. fig. 4 “globigerina” tripartita koch, jihar–1, interval 350–360 m, zone o3. fig. 5 “globigerina” venezuelana hedberg, jihar–1, interval 350–360 m, zone o3. fig. 6 tenuitella gemma (jenkins), jihar–1, interval 350–360 m, zone o3. fig. 7 globigerina angulisuturalis (bolli), jihar–5, interval 190–200 m, zone o4. fig. 8 globigerina angulisuturalis (bolli), detail of the wall texture, jihar–5, interval 190–200 m, zone o4. fig. 9 globigerina angulisuturalis (bolli), detail of the wall texture, jihar–5, interval 190–200 m, zone o4. fig. 10 “globigerina” venezuelana hedberg, jihar–1, interval 310–320 m, zone o4. fig. 11 chiloguembelina cubensis (palmer), jihar–5, interval 190–200 m, zone o4. fig. 12 chiloguembelina cubensis (palmer), detail of the wall texture, jihar–5, interval 190–200 m, zone o4. 37 1 2 3 4 5 6 7 8 9 10 11 12 hernitz kučenjak et al. plate 4 38 geologia croatica 59/1 plate 5 fig. 1 globigerina ciperoensis (bolli), jihar–4, interval 455–475 m, zone o5. fig. 2 cassigerinella chipolensis (cushman & ponton), jihar–1, interval 250–260 m, zone o5. fig. 3 cassigerinella chipolensis (cushman & ponton), detail of the wall texture, jihar–1, interval 250–260 m, zone o5. fig. 4 globigerina ciperoensis (bolli), jihar–5, interval 160–170 m, zone o6. fig. 5 paragloborotalia opima (bolli), jihar–4, interval 455–475 m, zone o5. fig. 6 paragloborotalia opima (bolli), detail of the wall texture, jihar–4, interval 455–475 m, zone o5. fig. 7 globigerina ciperoensis (bolli), detail of the wall texture, jihar–5, interval 160–170 m, zone o6. fig. 8 paragloborotalia nana (bolli), jihar–5, interval 180–190 m, zone o5. fig. 9 paragloborotalia nana (bolli), detail of the wall texture, jihar–5, interval 180–190 m, zone o5. fig. 10 streptochilus pristinum broenniman, jihar–5, interval 160–170 m, zone o6. fig. 11 globigerina angulisuturalis (bolli), jihar–1, interval 220–230 m, zone o6. fig. 12 globigerina angulisuturalis (bolli), detail of the wall texture, jihar–1, interval 220–230 m, zone o6. 39 1 2 3 4 5 6 7 8 9 10 11 12 hernitz kučenjak et al. plate 5 40 geologia croatica 59/1 1. introduction the objective of this research was to explore the potential of hand held space shuttle photographs for remote sensing analysis of meteorite impact craters. functionality of the existing on line databases was also studied and results obtained from other sensors (sirc/x-sar) are discussed and compared. 1.1. meteoritic impact craters meteoritic craters are circular depressions formed by the impact of a meteorite on a planetary body. explosive impact craters are formed by large meteorites (hodge, 1994). smaller meteorites (up to few metres in diameter) do not have a sufficient energy to cause an explosion. they produce dug craters with diameters of less than 10 metres (hodge, 1994). morphologically impact craters can be divided into two main groups: simple craters (fig. 1) and complex structures (craters) (fig. 2) (grieve, 1991). simple craters consist of a bowl shaped depression with an uplifted rim. complex structures (table 1) form at crater diameters above 2 km in sedimentary rocks and greater than 4 km in magmatic rocks. they consist remote sensing analysis of selected terrestrial impact craters and a suspected impact structure in south korea using space shuttle photographs neven trenc 1, ken m. morgan 2, r. nowell donovan 2 and arthur b. busbey2 of a central peak, an annular trough and outer uplifted rim (grieve, 1991). as a result of his study of lunar craters melosh (1989), defined multiring basins as a separate class of features characterized by at least two asymmetrical scarped rings (one of which may be the original rim of the crater). in 1996, 153 terrestrial impact craters were known (grieve et al., 1995). their diameters vary from 10 m to 300 km (since pits smaller than 10 m are not included in the record) (hamilton, 1996). the earth’s meteoritic record, when compared to other terrestrial planets shows a deficit of smaller and older features. this phenomenon reflects the processes of erosion and sedimentation that are active on the earth surface and tend to “heal” impact effects (grieve, 1990). shock metamorphic effects are exclusively associated with meteoritic impacts. no other natural process generates such extreme pressures and temperatures in such short time (grieve, 1990). they include shatter cones, formation of planar deformation features in quartz and feldspar grains, formation of diaplectic glass and high-pressure polymorphs of some minerals. 1.2. use of remote sensing in the analysis of meteoritic impact craters remote sensing has been successfully used for the analysis of meteorite craters on the earth as well as on the other planets and the moon. g eol. croat. 52/2 203 215 10 figs. 4 tabs. zagreb 1999 key words: shuttle photographs, meteoritic craters, manicouagan, aorounga, roter kamm, meteor crater, south korea. kljuëne rijeëi: snimci sa space shuttle-a, meteoritski krateri, manicouagan, aorounga, roter kamm, meteor crater, juæna koreja. 1 idrijska 35, hr-10000 zagreb, croatia. 2 texas christian university, dep. of geology, box 298830, fort worth, texas 76129, usa. abstract typical morphological elements for impact craters were detected on all analyzed shuttle photographs. features with diameters smaller than 2 km could not be successfully analyzed. the search for suitable shuttle scenes was successfully performed using on-line internet databases. image enhancement and lineament analysis were also performed on the acquired shuttle, landsat and spot images of a suspected impact feature in south korea. a fault bounded polygonal rim and a central uplift were identified on all images. a distinct system of annular and radial faults was not detected. the results of the study do not exclude the possibility of a meteoritic origin of this structure. saæetak morfoloπki elementi terena tipiëni za udarne strukture identificirani su na svim prouëavanim fotografskim snimcima sa space shuttle-a. strukture manje od 2 km nije bilo moguêe uspjeπno analizirati. identifikacija odgovarajuêih fotografija sa shuttle-a ostvarena je pretraæivanjem mreænih baza podataka s interneta. analizirani shuttle, landsat i spot snimci moguêe meteoritske strukture u juænoj koreji pokazuju rasjedima okruæeni poligonalni rub te centralno uzdignuêe, no jasan sustav anularnih i radijalnih rasjeda nije bio registriran. rezultati analize nisu osporili moguênost da je meteoritski udar uzrokovao postanak ove strukture. 204 geologia croatica 52/2 typical morphological indicators of impact craters on satellite images include: circular raised rims, polygonal shape (in complex craters), central uplifts (within the craters), radial drainage patterns (garvin et al., 1992), and dissected topography (butler, 1994). lineament analysis of impact features often reveals radial or annular fault and fracture patterns (figs. 3 and 4) (innes, 1964; butler, 1994) in the crater vicinity. sabins (1996) summarized some remote sensing characteristics of impact craters on venus and their specific signatures on radar imagery (table 2). garvin et al. (1992) suggested that the impact induced change of the spectral signatures, characteristic for the mineral quartz in the thermal infrared region, could be used for the recognition of impact features on the multispectral imagery. impact breccia deposits (garvin et al., 1992) showed characteristic signature on the third, fourth and fifth principal component colour imagery of the zhamanshin crater (russia). the proceses of erosion and sedimentation impede recognition of terrestrial crater and they can distort and even totally remove the morphological imprint of a crater. a number of other geological processes (volcanism, doming, folding etc.; roland, 1976) can create ring structures (olui∆, 1983) that may mimic meteoritic craters. 2. methods 2.1. space shuttle photographs since 1982 space shuttle astronauts have used hand held and mounted cameras to take photographs during their stay in space (eros, 1996). each shuttle mission produces from 4,000 to 5,000 photographs and approximately 125,000 photographs have been taken since the beginning of the project (eros, 1996). over eighty percent of the photographs are views of the earth (eros, 1996) and display large variations of angle, lighting and season (muehlberger, 1996). three main types of cameras used in the project are: hasselblad 500/m 70 mm, linhof aero technika 45 127 mm and large format camera (lfc) (eros, 1996) (table 3). an lfc camera was used only on the mission 41-g and these photographs provide stereo coverage over certain areas (eros, 1996). a majority of these images are regular rgb photographs, though some black and white and colour-infrared scenes have been taken (eros, 1996). spatial resolution of the photographs is dependent on the camera and the lens used and ranges between 150 and 20 m. 2.2. space shuttle archives and databases after each shuttle mission, rolls of film are sent to the johnson space center’s image science division in houston. photographs are processed and classified in three groups: earth observation images, experiment images and public release images (jsc, 1994). datasets are digitized at the capture station and targa files of approximately 1.1 m (756 by 486 pixels with 8 bits per colour) are produced (jsc, 1994). a portion of files is displayed to the public over the internet or in the form of videodisc (jsc, 1994). however, because of relatively poor resolution, scenes from a disc and the internet are not suitable for the remote sensing analysis. fig. 1 schematic presentation of a simple crater (modified from grieve, 1991). sl. 1 shematski prikaz jednostavnog kratera (prema grieve, 1991). fig. 2 schematic presentation of a complex strucuture (modified from grieve, 1991). sl. 2 shematski prikaz kompleksne strukture (prema grieve, 1991). group central one few peak ring rings central peak craters yes no no central peak basins yes yes no peak ring basins yes yes no multi ring basins yes no yes table 1 groups of complex craters (pike, 1985). datasets with a higher resolution must be obtained directly from jsc. in this study, the initial search for suitable scenes of impact craters was performed through the online databases at the earth science branch of the lyndon b. johnson space center web site (http://www.jsc.nasa. gov). the database, space shuttle earth observations project database of photographic information and images (jsc, 1996) http://eol.jsc.nasa.gov/sseop) was accessed through the internet (www) and a text search was performed. space shuttle earth observations videodisc (19811991), released to the public by johnson space center, with approximately 91,500 still images of the earth taken during the space shuttle missions sts-1 through sts-44 was used to identify optimal scenes. the film rolls with selected scenes were later located in the shuttle archive at the lockheed martin building in houston and transported to the lyndon b. johnson space center. a limhof digital camera, adobe photoshop software and macintosh hardware were used in the center to digitize the photographs. nominal resolution was around 500 dpi and the size of created files varied between 5 and 10 m. the original resolution of shuttle photographs was inevitably reduced during the process. the main limiting factors were mounting and the optical characteristics of the limhof camera. 205trenc, morgan, donovan & busbey: remote sensing analysis of selected terrestrial impact craters... fig. 3 rings and faults associated with haughton impact structure (canada) (modified from robertson, 1980). sl. 3 prstenovi i rasjedi vezani za haughton strukturu (prema robertson, 1980). fig. 4 schematic map of prominent lineaments around deep bay impact structure (canada) (modified from innes, 1964). sl. 4 shematski prikaz znaëajnijih lineamenata u okolici deep bay strukture (prema innes, 1964). material description radar signature lava plain lava flows impacted by the bolids. many plains are dark to intermediate depending on flat and featureless. others are faulted and folded to roughness. bright linear features are various degrees. fault scarps. rim ejecta deposited up to three crater radii from the bright near rim, becoming intermediate centre. coarse hummocky material near the centre outward with bright patches. becoming somewhat finer outward. wall rough terraced deposits on steep inner slopes. bright to intermediate. annular zone slump blocks and talus are common. surrounding the crater floor. floor level to smooth interior plains ranging from smooth bright to dark, circular to irregular to hummocky surfaces. materials include impact melt, outline. shocked rock, fallback or volcanic fill. very bright with characteristic peaks and rings peaks and ridges within the craters that rise above morphology. the floor materials. uplifted, shocked, crushed and sheared rock. outflow fluidized material formed by impact that resembles bright to intermediate with a lava flow. at some larger craters outflows extend flowerlike outline. for hundreds of kilometres. table 2 impact affected materials on radar imagery (sabins, 1996). 206 geologia croatica 52/2 data were stored on an external hard drive and transported to the texas christian university center for remote sensing and energy research for further processing. 2.3. sir-c/x-sar images and databases sir-c/x-sar (spaceborne imaging radar-c/xband synthetic aperture radar) was flown on two shuttle missions in 1994 (evans & plaut, 1996). it combines two radar devices: sir-c and x-sar. the instrument acquires quad polarized (l, c band) as well as single polarized (x-band) impulses (freeman, 1996). the resolution varies between 10 and 50 m (evans & plaut, 1996). to create sir-c/x-sar false colour images red, green and blue colours are assigned to different band/polarization combinations (jpl, 1996). radar scenes used in this study were downloaded from jpl’s space radar images of the earth web site (http://www.jpl.nasa.gov/radar/sircxsar) this web page displays over 150 sir-c/x-sar false colour images classified in eight thematic categories and listed by geographic locality. each image can be downloaded over the world wide web as a jpeg file with a low (size around 140 k) and high (file size around 10 m) resolution. 2.4. image processing and lineament detection image processing was performed at the texas christian university center for remote sensing and energy research on a power macintosh 9500/132 with 50 m ram. the dimple image-processing program was utilized for relative rectification of the shuttle photographs to sir-c/x-sar image. a linear gcp model and nearest neighbour resampling method were used. true north was determined on all the images. image datasets were either geographically corrected (radar) or fairly undistorted (shuttle). since only the relative posi tion of the detected features in respect to the impact structures was significant in this study, strict geographi cal rectification was not performed. adobe photoshop was used for image enhancement. contrast stretching was applied on all shuttle photographs and four custom directional convolution kernels were used for edge enhancement: north, east, northwest and southwest illumination. the original image and four derived filtered images were placed in separate layers of a single adobe illustrator document. a lineament is defined as a “mappable, simple or composite linear feature of a surface whose parts are aligned in a rectilinear or slightly curvilinear relationship and which differ distinctly from the patterns of adjacent features” (o’leary et al., 1976). an additional layer in the adobe illustrator was used for tracing of the lineaments. the results obtained from various image layers were compared and an attempt was made to eliminate all lineaments that were not structurally related (e.g., sand features caused by prevailing winds). mapict software (developed by dr. arthur busbey at tcu) was used to digitize traced lineaments and create text files, which were imported into rosy (rockware) software for production of rose diagrams. 3. results and discussion pictures of several impact structures were retrieved from the shuttle database. those with the best characteristics for remote sensing were selected (table 4, fig. 5). they represent various size categories of mappable impact craters on earth. diameters of the studied features ranged between 1.2 and 100 km. 3.1. the manicouagan the manicouagan (canada) impact structure (figs. 5 and 6) is located at 51°23’n 68°42’w (floran & dence, 1976). the age is estimated to be around 214 ma (floran & dence, 1976). the impact area is in the grenville province of the canadian shield (orcamera lens spatial sensor with a resolution comparable resolution hasselblad 500 el/m 100 mm 150 m mss (80 m) hasselblad 500 el/m 250 mm 30 m tm (30 m) linhof aero technika 250 mm 30 m tm (30 m) large format camera n/a 20-30 m spot hrv* (20 m) tm (30 m) table 3 spatial resolution of space shuttle photographs (eros, 1996). *) multispectral mode. feature size size rank manicouagan (canada) 100 km 5 aorounga (chad) 17 km 40 roter kamm (namibia) 2.5 km 119 meteor crater (arizona) 1.2 km 130 suspected structure 13 km in south korea table 4 impact structures with the best characteristics for remote sensing. 207trenc, morgan, donovan & busbey: remote sensing analysis of selected terrestrial impact craters... phal, 1978). petrological grenville units recognized in the manicouagan area (fig. 7) include meta-gabbros, meta-anorthosites and granitic gneisses (orphal, 1978). long periods of erosion and glaciation have substantially affected the appearance of this structure (floran & dence, 1976). remote sensing analysis of the manicouagan crater shows the typical pattern of annular lineaments that define the polygonal rim of other complex impact structures. orientation of these faults coincides with the typical fault and fracture patterns in the area (ne, n) and supports the assumption (floran & dence, 1976) that these faults follow preimpact structures and zones of weakness. radial drainage and other characteristics typical for such features (central uplift annular trough) were also identified on the photograph. 3.2. aorounga the aorunga impact structure (figs. 8 and 9) is located at 19°06’n and 19°15’e near the tibesti massif in the borkou region of eastern chad (beck-giraduon et al., 1992). the diameter of the crater is around 17 km (jpl, 1996) the age of the structure was estimated as late devonian on the basis of the overlying sediments (ocampo, 1996). a shuttle photograph of the feature was analyzed and compared with the sir-c/x-sar (fig. 9) dataset that was downloaded from the jpl internet site. all the elements of the structure are well developed and easily recognized. crater rim, peak ring and central uplift were identified on both images. on the shuttle image, sand covered areas are lighter coloured while exposed bedrock is displayed as a dark gray. central uplift can be identified as a dark patch of the exposed fig. 5 locations of selected craters. sl. 5 poloæaj odabranih kratera. fig. 6 schematic geologic map of the manicouagan structure (modified from orphal, 1978). sl. 6 shematska geoloπka mapa strukture manicouagan (prema orphal, 1978). fig. 7 lineament map of the manicouagan impact crater based on shuttle photograph (photograph credit: jsc, 1996). sl. 7 karta lineamenata oko kratera manicouagan temeljena na shuttle fotografiji (izvor snimka jsc, 1996). 208 geologia croatica 52/2 bedrock in the centre of the structure. radar penetrates up to several feet of dry sand (mchone et al., 1996) showing more accurate morphology of the structure than the shuttle image. the polygonal shape of the fault-bounded crater and annular system of lineaments, typical for an impact structure, were observed on both images. a comparison of the obtained results has shown that a larger number of lineaments was detected on the radar image. the frequency of n-s lineaments was also higher on this image. one of the main problems in the analysis was distinction between the structurally related lineaments and typical eolian features (orientation ne-sw) these masking effects, that were more pronounced on the shuttle photograph, are probably the main cause for the mentioned differences of the results obtained from the analysis of two images. 3.3. smaller features: roter kamm and meteor crater the roter kamm impact crater is located at 27°46’s and 16°18’e in the southern part of the namib desert (namibia) (fudali, 1973). the crater has a diameter of 2.5 km and its age has been estimated around 3.7 ma (grieve et al., 1995). meteor crater is located at the 35°02’n and 111°01’w in the canyon diablo region of the north central arizona (usa) (shoemaker, 1977). the age of the impact is around 49 ka (grieve et al., 1995). the structure has a diameter of 1,220 m (grieve et al., 1995). on the shuttle photographs of these two smaller features, both located in the arid region, only the polygonal fault bounded rim and very few lineaments could be identified. the main problems were the small size of the features, low resolution of the photographs and sand cover. 3.4. suspected impact structure in south korea a suspected impact structure in south korea is centred at 37°49’n and 127°03’e (jones et al., 1995). it is located 20 km north of seoul near the town of uijongbu in the vicinity of the demilitarized zone (jones et al., 1995). in 1994, the crew of the space shuttle endeavor (sts-59) took the first photograph of the structure. jones et al. (1995) have described the structure and discussed its formation. a circular rim with a 13 km diameter and a central uplifted region characterize the crater like feature (jones et al., 1995). relief from the bottom to the crest is greater than 400 m (jones et al., 1995). hilly uplifted terrain encircles the structure, which is situated in the jurassic granites and surrounded by the 2 ga old metamorphic complex of gneiss and schist. the northsouth oriented tongducheon fault cuts the structure in half (jones et al., 1995). kang et al. (1985) suggested that fracturing along the circular joint during cooling of the granite pluton induced formation of the structure. jones et al. (1995) questioned the possibility of a magmatic origin for the structure and suggested that it was caused by a meteoritic impact. future study of rock samples from the site is expected to give definite information about its formation. the analysis has shown that the identification of lineaments was equally successful on shuttle and landsat tm images. a somewhat bigger number of lineaments were detected on the spot image due to its better spatial resolution fig. 8 lineament map of the aorounga impact structure based on shuttle photograph (image credit: jpl, 1996). sl. 8 karta lineamenata oko kratera aorounga temeljena na shuttle fotografiji (izvor snimka jpl, 1996). fig. 9 lineament map of the aorounga structure based on sir-c/xsar image. sl. 9 karta lineamenata oko kratera aorounga temeljena na sirc/x-sar snimci. 209trenc, morgan, donovan & busbey: remote sensing analysis of selected terrestrial impact craters... the possible crater rim and uplifted peak were recognized on the shuttle photograph (fig. 10) as well as on studied spot and landsat tm scenes. however, the eastern part of the rim is much better defined on the images than the western half. two large lineaments that cut the structure (one of them corresponding to the tongduchen fault) are clearly visible. lineaments identified on the images mark a characteristic fault-bounded polygonal rim. besides these well-pronounced lineaments of the “crater rim” numerous shorter lineaments with various orientations were detected on the scenes. they represent linear ridges and valleys. though some of them have annular and radial orientations with respect to the structure, this information is not significant in the view of the large overall dispersion of lineament azimuths. in lower elevation areas covered by agricultural fields detection of lineaments was not possible. the structure does show some typical elements that were identified on the shuttle photographs of other proven impact features but they are not completely developed and the results of the analysis do not provide definite arguments for either hypothesis about the formation of the structure. 4. conclusion space shuttle photographs have a good remote sensing potential but their use for the remote sensing analysis of impact craters was limited. limiting factors include relatively low photographic resolution, nondigi tal format and restricted areal coverage. identification of the scenes with craters can be successfully performed from online and videodisc databases and a text search by the key word or geographic location is the fastest way to obtain the required data. image enhancement and edge enhancement techniques were successfully applied on the scanned shuttle photographs. however, limited mapping could be performed. some elements of characteristic fault and fracture patterns for the impact features were identified on all studied images but results obtained from the photographs of features smaller than 2 km were significantly inferior. improved resolution, digital format and a mission dedicated to the photography of impact craters are needed to improve the potential of space shuttle photographs for analysis of impact craters. acknowledgments this research would not be possible without the support of the following organizations: texas christian university research foundation, nasa, adkins research fund and lyndon b. johnson space center. dr arthur ehlmann (texas christian university) provided valuable advises regarding literature and internet resources. the authors would especially like to thank lt. col. ned fleming and sue runco from jsc. we would also like to thank dr ivo veli∆ and dr marinko olui∆ for their extremely useful suggestions and editing of the paper. 5. references baji∆, m. (1985): an approach to simulation of the imaging by synthetic aperture radar.bilt. daljin. istraæ. fotointerpret., 1/11, 1-13, zagreb. beck-giraduon, j.f., rouzeau, o., goachet, e. & solages, s. (1992): impact hyperveloce d’une meteorite geante a l’origine de la depression circulaire d’aorounga au tchad (afrique).comptes rendus de l’academie des sciences, serie 2, 315/1, 83-88. butler, h.r. (1994): lineament analysis of the sudbury multiring impact structure.in: dressler, b.o., grieve, r.a.f. & sharpton, v.l. (eds.): large meteorite impacts and planetary evolution. geological society of america special paper, 319329. eros (1996): space shuttle earth observation program, eros data center web site, http:// edcwww. c r . u s g s . g o v / w e b g l i s / g l i s b i n / g u i d e . p l / g l i s / h y p e r / g u i d e/shuttle. evans, d.l. & plaut j.j. (1996): science results fig. 10 lineament nap of the korean structure based on shuttle photograph (photograph credit: jsc, 1996). sl. 10 karta lineamenata oko korejske strukture temeljena na shuttle fotografiji (izvor snimka jsc, 1996). 210 geologia croatica 52/2 from the spaceborne imaging radar-c/x-band synthetic aperture (sir-c/x-sar): progress report radar.http://southport.jpl.nasa.gov/progressreports0496/ tableofcontents.html. floran, r.j. & dence, m.r.m. (1976): morphology of the manicouagan impact structure, quebec, and some comparison with lunar basins and craters.7th lunar. sci. conf, proceedings, 2845-2865, houston. freeman, t. (1996): what is imaging radar.jet propulsion laboratory web site, http://southport.jpl. nasa.gov/index.html. fudali, r.f. (1973), roter kamm, evidence for an impact origin.meteoritics, 3, 245-257. garvin, j.b., schnetzler, c.c. & grieve, r . a . f . (1992): characteristics of large terrestrial impact structures as revealed by remote sensing studies.tectonophysics, 216, 45-62. grieve, r.a.f. (1990): impact cratering on earth.scientific american, april, 66-73. grieve, r.a.f. (1991): terrestrial impact: the record in rocks.meteoritics, 26, 175-194. grieve, r.a.f., rupert, j., smith, j. & therriault, a. (1995): the record of terrestrial impact cratering.gsa today, 5/10, 191-196. hamilton, c.j. (1996): terrestrial impact craters.h t t p : / / w w w . h a w a s t s o c . o r g / s o l a r / e n g / t e r c r a t e . h t m #intro hodge, p. (1994): meteorite craters and impact structures of the earth.cambridge university press, cambridge, 124 p. innes, m.j.s. (1964): recent advances in meteorite crater research at the dominion observatory, ottawa, canada.meteoritics, 2/3, 219-241. jpl (1996): jet propulsion laboratory public information office, imaging radar homepage http://www. jpl.nasa.gov/radar/sircxsar/. jones, t.d., fleming, n., hatheway, a.w., mcintosh, w. & shellum, c.j. (1995): the seoul impact structure discovery and assessment.unpubl. jsc (1994): johnson space center, nasa jsc digital image collection, http://images.jsc.nasa.gov/iams/ html/index.html. j s c (1996): johnson space center, space shutle earth observation project (sseop) http://eol.jsc.nasa. gov/sseop/. kang, p.c., chi, k.h., min, j.c. & young, s.c. (1985): a geologic study of the seoul-dongducheun lineament using digital image processing techniques of landsat data.journal of korean society of remote sensing, 1/1, 39-51. mchone, j.f., greenly, r. & blumberg, d. ( 1 9 9 6 ) : sir-c/x-sar radar studies: impact and eolian features, borkue region, northern chad.lunar and planetary science conference, abstracts, 27/2, 849-850, houston. melosh, h.j. (1989): impact cratering.oxford university press, oxford, 245 p. muehlberger, w.r. (1996): environmental applications of hand held photography taken from the space shuttle.proceedings of the 11th thematic conference on geologic remote sensing, environmental research institute of michigan, 1, 227. ocampo, a.c. (1996): shuttle imaging radar (sirc) images reveal multiple impact craters at aorounga, northern chad.lunar and planetary science conference, abstracts, 27, 2, 977-978. o’leary, d.w., friedman, j.d. & pohn., h.a. (1976): lineament, linear, lineation: some proposed new standards for old terms.geological society of america bulletin, 87, 1463-1469. olui∆, m. (1983) daljinska istraæivanja u geologiji.in: donassy, v, tomasegovi∆, z. & olui∆, m.: daljinska istaraæivanja u geoznanostima. jazu, 141-268, zagreb. olui∆, m. (1985): globalni program snimanja i istraæivanja zemlje iz svemira do 2000. godine.bilt. daljin. istraæ. fotointerpret., 1/11, 49-57, zagreb. orphal, d.n. (1978): an alternative model for the manicouagan impact structure.9th lunar. planet. sci. conf., proceedings, 2695-2712, houston. pike, r.j. (1985): some morphology systematics of complex impact structures.meteoritics, 20/1, 4968. robertson, p.b. (1980): haughton impact structure.lunar planet. sci. conf., proceedings, 895896. roland n.w. (1976): die ringstruktur aorounga (borkou, sud-sahara).geologische jahrbuch, a.33, 117-131. sabins, f.f. (1996): remote sensing principles and interpretation.w.h. freeman and co., new york, 447 p. shoemaker, e.m. (1977): penetration mechanics of high velocity meteorites, illustrated by meteor crater arizona.in: mccall, g.j.h. (ed.): meteoritic craters. dowden, hutchinson and ross, 170186. 211trenc, morgan, donovan & busbey: remote sensing analysis of selected terrestrial impact craters... manuscript received july 26, 1999. revised manuscript accepted november 12, 1999. 1. uvod cilj ovog rada bio je istraæiti potencijalnu vrijednost fotografija snimljenih iz letjelice space shuttle za analizu struktura meteoritskog podrijetla primjenom metoda daljinskih istraæivanja. testirana je i funkcionalnost postojeêih baza podataka na internetu te moguênost brze identifikacije odgovarajuêih shuttle-ovih fotografija ovim putem. rezultati dobiveni na temelju fotografija sa shuttle-a usporeeni su s onima dobivenima pomoêu drugih senzora pa su tako pri analizi strukture aorounga koriπteni i radarski snimci sa letjelice shuttle (radi se o ureaju sir-c/x-sar, spaceborne imaging radar-c/x-band synthetic aperture radar (freeman, 1996) slikovni radar za snimanje iz svemirac/x-radar sa sintetiëkom antenom (baji∆, 1985; olui∆, 1985)). pri obradi potencijalnog meteoritskog kratera u juænoj koreji, uporabljeni su i satelitski snimci dobiveni pomoêu tematskog kartografa (tm-thematic mapper) sa satelita landsat te senzora hrv (high resolution visible) postavljenog na satelitu spot. 1.1. meteoritski krateri meteoritski krateri su kruæne depresije nastale djelovanjem meteorita na planetarno tijelo. eksplozivni krateri nastaju djelovanjem veêih meteorita, dok manji meteoriti (do nekoliko metara u promjeru) nemaju dovoljnu energiju da izazovu eksploziju. oni stvaraju iskopne kratere s promjerima manjim od 10 m (hodge, 1994). morfoloπki, meteoritski krateri mogu se podijeliti u dvije glavne skupine: jednostavni krateri (sl. 1) i kompleksne strukture (krateri) (sl. 2) (grieve, 1991). jednostavni krateri su depresije u obliku zdjele na zemljinoj povrπini s uzdignutim rubom. kompleksne strukture (tablica 1) nastaju kod radijusa veêih od 2 km u sedimentnim stijenama i 4 km u magmatskim stijenama. one se sastoje od centralnog uzdignuêa kruænog jarka i vanjskog uzdignutog ruba (grieve, 1991). na temelju studija mjeseëevih kratera melosh (1989) je definirao bazene s viπe prstenova kao posebnu skupinu struktura karakteriziranih sa barem dva asimetriëna prstena (od kojih jedan moæe biti i originalni rub kratera). godine 1995. bilo je poznato 153 meteoritskih kratera (grieve et al., 1995). njihov promjer varira od 10 m do 300 km (udubine manje od 10 m nisu kategorizirane) (hamilton, 1996). kad se broj i veliëina meteoritskih kratera na povrπini zemlje usporedi s drugim planetima sliënih karakteristika, uoëljivo je da se na zemlji manje i starije strukture javljaju razmjerno rjee. ovaj fenomen odraz je procesa erozije i sedimentacije koji djeluju na njezinoj povrπini i “briπu” tragove djelovanja meteorita (grieve, 1990). metoritski udari uzrokuju ekstremno visoke pritiske i temperature tijekom izuzetno kratkog vremenskog intervala te su oni jedini prirodni proces koji moæe izazvati pojavu specifiënih “udarnih” metamorfnih efektata (shock metamorphic e f f e c t s grieve, 1990), koji se smatraju kljuënim dokazom meteoritskog podrijetla neke strukture. neki od tipiënih efekata su nastanak konusnih pukotina (shatter cones ) u udarom zahvaêenim stijenama, nastanak planarnih deformacijskih pojava u zrnima kvarca i feldspata te nastanak dijaplektiëkih stakala i visokotemperaturnih polimorfa nekih minerala (grieve, 1990). 1.2. primjena daljinskih istraæivanja u analizi meteoritskih kratera daljinska se istraæivanja uspjeπno primjenjuju u analizi meteoritskih kratera na zemlji, drugim planetima i mjesecu. tipiëni morfoloπki indikator meteoritskih kratera na satelitskim snimcima su kruæni uzdignuti prstenovi, poligonalni oblik (kod kompleksnih kratera) centralna uzdignuêa (unutar kratera), radijalni povrπinski tokovi (garvin et al., 1992), te isprekidana topografija (butler, 1994). analize lineamenata uz meteoritske kratere obiëno pokazuju anularne i radijalne sustave rasjeda (sl. 3 i 4) (innes, 1964; butler, 1994). sabins (1996) je prikazao karakteristike kratera na veneri i njihove tipiëne odraze na radarskim snimcima (tablica 2). garvin et al. (1992) navode da se udarom izazvane promjene u spektralnim vrijednostima tipiënim za mineral kvarc, u termalnom infracrvenom podruëju, mogu koristiti za prepoznavanje meteoritskih struktura na multispektralnim snimcima. naslage udarnih breëa kod kratera zhamanshin (rusija) mogle su se uspjeπno izdvojiti digitalnim procesiranjem satelitskih snimaka (transformacijom 3., 4. i 5. osnovne komponente) (garvin et al., 1992). procesi erozije i sedimentacije oteæavaju prepoznavanje struktura nastalih meteoritskim udarom i mogu promijeniti ili analiza odabranih meteoritskih kratera i moguêe meteoritske strukture u juænoj koreji na temelju space shuttle-ovih fotografija neven trenc , ken m. morgan , r. nowell donovan & arthur b. busbey vrsta centralno jedan viπe uzdignuêe prsten prstenova krateri sa centralnim uzdignuêem da ne ne bazeni sa centralnim uzdignuêem da da ne bazeni sa uzdignuêem i prstenom da da ne bazeni sa viπe prstenova da ne da tablica 1 tabliëni prikaz vrsta kompleksnih kratera prema pikeu (1985). 212 geologia croatica 52/2 ëak potpuno uniπtiti morfoloπki otisak kratera. po svojim karakteristikama mnogi se dokazani meteoritski krateri mogu svrstati u skupinu prstenastih struktura (olui∆, 1983). ova kategorija obuhvaêa sve morfostrukturne elemente reljefa polukruænog ili eliptiënog oblika, i takve forme se vrlo dobro uoëavaju na razliëitim snimcima koji se koriste u daljinskim istraæivanjima (olui∆, 1983). prema istom autoru uzrok nastanka ovih struktura (uz meteoritske udare) mogu biti vulkanska ili magmatska djelatnost, tektonski poremeêaji ili dijapirizam. meteoritske strukture je ëesto vrlo teπko razluëiti od prstenastih struktura drugaëijeg podrijetla (roland, 1976) no ako su opisani specifiëni indikatori dobro oëuvani, te ako je prisutno nekoliko karakteristiënih elemenata (npr. rub kratera i centralno uzdignuêe), rezultati analize metodama daljinskih istraæivanja mogu s dosta velikom vjerojatnoπêu ukazati na postanak putem meteoritskog udara. 2. metode 2.1. fotografski snimci na»injeni sa space shuttle-a od 1982. godine astronauti na space shuttle-u se sluæe ruënim foto kamerama i kamerama na stativu prilikom snimanja iz svemira (eros, 1996). svaka shuttle-ova misija naëini nekoliko tisuêa fotografija, pa je do sada snimljeno oko 125.000 snimaka (eros, 1996). viπe od 80% fotografija su pogledi na planet zemlju i naëinjene su iz razliëitih kutova, pod raznovrsnim osvijetljenjima i tijekom svih godiπnjih doba (muehlberger, 1996). tri glavna tipa kamera koriπtenih tijekom space shuttleovih misija su: hasselblad 500/m 70 mm, linhof aero technika 45-127 mm i large format camera (lfc) (tablica 3; eros, 1996). kamera velikog formata je koriπtena samo u misiji 41 g i tom su prilikom naëinjene stereo-fotografije nekih podruëja (eros, 1996). veêinom su to normalne kolor fotografije (rgb), premda su napravljene i neke crno-bijele i kolor-infracrvene snimke. prostorna rezolucija fotografija ovisi o kameri, visini snimanja i upotrebljenoj leêi, te varira izmeu 150 i 20 m. 2.2. space shuttle arhivski snimci i baze podataka nakon svake shuttle-ove misije eksponirani filmovi se πalju u image science division johnson space centra u houstonu. fotografije se nakon obrade svrstavaju u tri grupe: slike promatranja zemlje, slike pokusa, i slike za javnu uporabu (jsc, 1994). fotografije se zatim digitaliziraju te nastaju targa datoteke od oko 1.1 megabajta (mb) (756 x 486 piksela s 8 bita). dio datoteka se predstavlja javnosti putem interneta te u formi videodiska (jsc, 1994). kako snimci s video diska i interneta nisu namijenjeni za znanstveno-struëna istraæivanja, oni imaju razmjerno slabu rezoluciju te je odgovarajuêe datoteke sa viπom rezolucijom potrebno dobaviti direktno iz johnson space center-a. za ovaj rad inicijalna potraga za odgovarajuêim snimkama meteoritskih kratera je izvrπena preko web stranice earth science branch of the lyndon b. johnson space center (http://www.jsc.nasa.gov/). mreæna baza podataka “space shuttle earth observations project database of photographic information and images” (jsc, 1996) http://eol.jsc.nasa.gov/ sseop/ kontaktirana je preko www (world wide web) te je izvrπeno pretraæivanje putem kljuënih rijeëi. za identifikaciju optimalnih scena koriπten je takoer i video disk, space shuttle earth observations video disc (1981-1991), u izdanju johnson space center-a s oko 91.500 snimaka zemlje naëinjenih tijekom misija sts-1 do sts-44. kolutovi filmova s odabranim snimkama su zatim identificirani u shuttle arhivu u lockheed martin building (houston) i preneπeni u lyndon b. johnson space center. limhof digitalna kamera, adobe photoshop program i macintosh raëunalo su koriπteni za digitalizaciju snimaka sa filmova. materijal opis orbitalni radarski snimak lavna ravnica tokovi lave s djelovanjem bolida. ravne i monotone tamne do srednje tamne ovisno o ili zahvaêene rasjedanjem i boranjem. stupnju hrapavosti povrπina. svijetle linearne strukture su rasjedne povrπine. rub izbaëeni materijal sedimentiran do tri kraterska radijusa svijetao u blizini ruba, postaje srednje daleko od centra. grubi humëasti materijal postaje finiji svijetao s vanjske strane sa svijetlim prema rubu. mrljama. zid grube terasaste naslage na strmim unutarnjim zidovima. anularna zona okruæuje dno kratera. prevaljeni blokovi i lepeze su ëesti. dno ravne do glatke unutarnje ravnice koje variraju od svijetao do taman, kruæan do glatkih do humëastih povrπina. materijal ukljuëuje nepravilan obris. rastaljene “udarene” stijene, pali materijal te vulkansko ispunjenje. uzdignuêa i prsteni uzdignuêa i prsteni unutar kratera koji se diæu iznad materijala dna. uzdignute udarene i napregnute stijene. vrlo svijetli s tipiënom morfologijom. izljevi fluidizirani materijal koji podsjeêa na tok lave . kod svijetao do srednje svijetao s obrisom nekih veêih kratera proteæe se na stotine kilometara. u obliku cvijeta. tablica 2 prikaz udarom zahvaêenih materijala na orbitalnim radarskim snimcima (sabins, 1996). 213trenc, morgan, donovan & busbey: remote sensing analysis of selected terrestrial impact craters... nominalna rezolucija je bila oko 500 dpi (dots per inch toëaka po inëu), a veliëina nastalih datoteka je varirala izmeu 5 i 10 mb. originalna rezolucija shuttle-ovih fotografija bila je neizbjeæno reducirana tijekom ovog procesa. glavni ograniëavajuêi faktor bili su stativ i optiëke karakteristike limhof kamere. podaci su zatim pohranjeni na prenosivi tvrdi disk i preneseni u texas christian university center for remote sensing and energy research na obradu. 2.3. radarski snimci s i r c / x s a r (spaceborne imaging radar-c/x-synthetic aperture radar slikovni radar za snimanje iz svemirac/x-radar sa sintetiëkom antenom) kombinira dva zasebno razvijena radarska ureaja sir-c i x-sar te prima “quad” polarizirane (l, c kanali) impulse kao i vv polarizirane (xkanal) impulse (freeman, 1996). ovaj instrument je bio koriπten tijekom dvije shuttle-ove misije u 1994. godini, a rezolucija prikupljenih podataka varira izmeu 10 i 50 metara (evans & plaut, 1996). crvena, zelena i plava komponenta na sir-c/x-sar umjetnoj kolor snimci zapravo predstavljaju razliëite kombinacije radarskih kanala i polarizacija signala (jpl, 1996). radarska snimka (scena) koja je koriπtena u ovoj studiji presnimljena je preko mreæe s jpl-ove space radar images of the earth web stranice (http://www.jpl. nasa.gov/radar/sircxsar/). ondje je predstavljeno 150 sir-c/x-sar snimaka (umjetni kolor), klasificiranih u osam tematskih kategorija s navedenim geografskim lokalitetima. svaki snimak moæe biti kopiran preko www kao jpeg datoteka s niskom rezolucijom (oko 140 kb) ili visokom rezolucijom (oko 10 mb). 2.4. procesiranje snimaka i analiza lineamenata snimke su obraene u texas christian university center for remote sensing and energy research, na power macintosh 9500/132 raëunalu s 50 mb ram-a. dimple program za obradu snimaka koriπten je za relativnu rektifikaciju shuttle fotografija spram sir-c/x-sar snimaka. primijenjen je linearni transformacijski model i metoda “najbliæeg susjeda” (nearest neighbour ). geografski smjer sjevera utvren je na svim snimcima, a kako su oni bili ili geometrijski ispravljeni (radar) ili priliëno nedeformirani (shuttle), precizno geografsko poboljπanje nije raeno jer je tijekom ovog istraæivanja bio znaëajan samo relativan poloæaj morfoloπkih i drugih elemenata spram struktura nastalih djelovanjem meteorita. aplikacija adobe photoshop je koriπtena za poboljπanje snimaka. tako je kontrast podeπen na svim shuttle fotografijama, a primijenjena su i ëetiri filtra za pojaëanje linearnih elemenata. smjerovi njihove iluminacije su bili sjever, istok, sjeverozapad i jugozapad. originalni snimak i ëetiri izvedene filtrirane snimke pohranjene su kao aplikacijski slojevi u jedinstvenom adobe illustrator dokumentu. lineament se definira kao jednostavni ili kompleksni linearni element ëiji su dijelovi rasporeeni pravocrtno ili blago zakrivljeno i koji se bitno razlikuje od susjednih struktura (o’leary et al., 1976). opaæeni lineamenti su izvuëeni na dodatnim aplikacijskim slojevima u sklopu adobe illustratora. rezultati dobiveni pomoêu razliëitih filtera su usporeeni pa su linearni elementi uzrokovani ljudskim aktivnostima ili nejasnog podrijetla bili odstranjeni kad god je to bilo moguêe. mapict program (dr a. busbey, texas christian university) koriπten je prilikom digitalizacije lineamenata koji su zatim uneπeni u aplikaciju “rosy” za izradu rozetnih dijagrama. 3. rezultati i diskusija snimci viπe meteoritskih kratera pronaeni su u shuttleovoj bazi podataka te su odabrani oni najprikladniji za obradu (tablica 4, sl. 5). promjeri istraæivanih struktura variraju izmeu 1,2 i 100 km, a zastupane su razliëite veliëinske kategorije meteoritskih kratera na zemlji. 3.1. manicouagan krater manicouagan krater u kanadi (sl. 5 i 6) smjeπten je u istoënom dijelu poluotoka labrador. starost mu je procijenjena na 214 milijuna godina (floran & dence, 1976). ovo podruëje pripada grenville provinciji kanadskog πtita te su u okolici kratera manicouagana utvrene razliëite petroloπke grenville jedinice (sl. 6), zastupane metagabrima, metaanortozitima i granitskim gnajsovima (orphal, 1978). dugotrajna izloæenost procesima erozije i glacijacije znatno je promijenila ovu strukturu (floran & dence, 1976). analiza kratera manicouagan metodama daljinskih istraæivanja pokazuje tipiëni sustav anularnih (kruæno rasporeenih) rasjeda koji definiraju poligonalni oblik kompleksnih udarnih struktura (sl. 7). orijentacija spomenutih rasjeda koincidira s najzastupljenijim pravcima lineamenata na ovom podruëju, sjeveroistok-jugozapad i sjever-jug, πto podupire kamera leêa prostorna senzor s usporedivom rezolucija rezolucijom hasselblad 500 el/m 100 mm 150 m mss (80 m) hasselblad 500 el/m 250 mm 30 m tm (30 m) linhof aero technika 250 mm 30 m tm (30 m) large format camera n/a 20-30 m spot hrv (20 m) tm (30 m) tablica 3 usporedni prikaz znaëajki razliëitih kamera i senzora za snimanje iz satelita (eros, 1996). struktura veliëina mjesto po vel. manicouagan (kanada) 100 km 5 aorounga (»ad) 17 km 40 roter kamm (namibija) 2.5 km 119 meteor crater (arizona) 1.2 km 130 moguêa struktura 13 km u juænoj koreji tablica 4 promjer i mjesto po veliëini analiziranih meteoritskih struktura. 214 geologia croatica 52/2 pretpostavku koju su iznijeli floran & dence (1976) da je njihov postanak bio uvjetovan strukturama i zonama slabosti koje su na terenu postajale prije meteoritskog udara. radijalni sustav povrπinskih tokova i druge karakteristike tipiëne za takve strukture (centralno uzdignuêe, kruæna depresija) su takoer identificirani na snimku. 3.2. aorounga struktura aorounga stuktura (sl. 5, 8 i 9) smjeπtena je u blizini tibesti masiva u borkou regiji istoënog »ada (beck-giraduon et al., 1992). promjer joj iznosi oko 17 km (jpl, 1996), a starost strukture je procijenjena na temelju pokrovnih sedimenata kao kasnodevonska (ocampo, 1996). shuttle fotografija ove strukture je analizirana i usporeena sa sir-c/x-sar (sl. 9) snimkom koja je preuzeta preko mreæe s jpl-ove internet stranice. reljefne forme tipiëne za meteoritske strukture na krateru aorounga su dobro izraæene i uoëavaju se na oba koriπtena snimka. na shuttle fotografiji pijeskom prekrivena podruëja su svijetlije obojena, dok je otkrivena stijena tamno siva. svi elementi strukture, rub, prsten i centralno uzdignuêe su jasno prepoznatljivi. centralno uzdignuêe moæe se identificirati na snimci kao tamna mrlja otkrivene stijene u srediπtu strukture. radarski zraci prodiru kroz nekoliko stopa suhog pijeska (mchone et al., 1996), te se spomenuti tipiëni elementi izvrsno uoëavaju. dva izvora podataka, koriπtena tijekom ovog istraæivanja (shuttleove rgb fotografije i sir-c/xsar snimci) meusobno su se nadopunjavali. pri tome je digitalizirana rgb fotografija dala kvalitetnu informaciju o tonalnim karakteristikama materijala na tlu, a na radarskom su snimku morfoloπki elementi strukture bili bolje izraæeni. usporedbom rezultata analize lineamenata utvreno je da ih je veêi broj detektiran na radarskoj snimci, te da je na njoj veêa zastupljenost lineamenata sa pravcem sjever-jug. veliku je poteπkoêu pri obradi predstavljalo razluëivanje izmeu lineamenata koji su vezani uz udarnu strukturu i eolskih pojava (orijentacija jugozapad-sjeveroistok). ovi maskirajuêi efekti pjeπëanog pokrova bili su snaænije izraæeni na shuttle fotografiji, pa se time mogu objasniti i razlike u analizama dvaju snimaka. 3.3. krateri roter kamm i meteor crater roter kamm (slika 5) udarni krater nalazi se u juænom dijelu pustinje namib, namibija (fudali, 1973). ovaj relativno mali krater ima promjer 2,5 km, a starost mu je procijenjena na oko 3,7 milijuna godina (grieve et al., 1995). meteor crater (sl. 5) je smjeπten u podruëju kanjona diablo, sjeverne-centralne arizone (sad) (shoemaker, 1977). udar meteorita prije pribliæno 49 tisuêa godina uzrokovao je nastanak te strukture ëiji promjer iznosi oko 1.220 m (grieve et al., 1995). na shuttle-ovim fotografijama navedenih manjih struktura, smjeπtenih u aridnom podruëju, bilo je moguêe registrirati samo poligonalni rub i nekoliko lineamenta. glavni problem su predstavljali mala veliëina strukture, niska rezolucija fotografija i pjeπëani pokrov. 3.4. mogu∆i meteoritski krater u juænoj koreji moguêi meteoritski krater u juænoj koreji smjeπten je oko 20 km sjeverno od seoula, kod grada uijongbu u blizini demilitarizirane zone (jones et al., 1995). posada space shuttle-a endaveor (sts-59) snimila je fotografije ove strukture tijekom jedne misije izvedene 1994. godine. jones et al. (1995) su prvi opisali taj moguêi meteoritski krater i raspravili njegov postanak. prema jones et al. (1995) polukruæni greben s promjerom od 13 km i centralno uzdignuêe karakteriziraju krateru sliënu strukturu. visinska razlika od dna do vrha grebena je veêa od 400 m a struktura je smjeπtena unutar jurskih granita, okruæenih s 2 milijarde godina starim gnajsovima i πistovima. rasjed tongducheon s orijentacijom sjever-jug presjeca strukturu na dva dijela. kang et al. (1985) navode da je pucanje duæ pukotine kruænog oblika tijekom hlaenja granitskog plutona uvjetovalo nastanak polukruæne forme, meutim jones et al. (1995) ne smatraju da je struktura magmatskog podrijetla te pretpostavljaju da se radi o ostatku meteoritskog kratera. buduêe studije uzoraka stijena iz kratera trebale bi dati relevantne informacije o njezinom podrijetlu. analiza navedene strukture je provedena na shuttle fotografijama te landsat tm i spot hrv snimcima. na sva tri snimka bilo je moguêe podjednako dobro registrirati morfoloπke elemente pretpostavljenog meteoritskog kratera. broj registriranih lineamenata bio je podjednak na shuttle fotografijama i landsatovim snimcima dok je bolja prostorna rezolucija spot snimka omoguêila zapaæanje neπto veêeg broja lineamenata (osobito oni kraêeg pruæanja). moguêi rub kratera i centralno uzdignuêe na snimcima se lako uoëavaju, no istoëni dio ruba kratera je znatno bolje ocrtan od njegove zapadne strane. dva snaæna lineamenta (jedan od njih odgovara tongducheon rasjedu) jasno se uoëavaju na snimci, a imaju pravac pruæanja sjever-jug i sjeveroistokjugozapad. osim dobro izraæenih lineamenata ruba kratera, na snimkama su registrirani brojni kraêi lineamenti s razliëitim orijentacijama. oni se manifestiraju kao linearne doline i grebeni. iako neki od njih imaju anularnu i radijalnu orijentaciju u odnosu prema strukturi, ovaj podatak nije znaëajan ako se uzme u obzir velika sveukupna disperzija pravaca ovih lineamenata. u niæim predjelima prekrivenim poljoprivrednim povrπinama identifikacija lineamenata nije bila moguêa. razmatrana prstenasta struktura pokazuje neke tipiëne elemente identificirane na shuttle-ovim fotografijama drugih dokazanih meteoritskih struktura (centralno uzdignuêe i dio ruba kratera), no oni nisu potpuno razvijeni i rezultati analize ne daju definitivne argumente za bilo koju od hipoteza o njezinom postanku. 4. zaklju»ak koriπtene space shuttle fotografije imaju ograniëenu primjenu u daljinskoj analizi meteoritskih kratera. ograniëavajuêi faktori su relativno slaba prostorna rezolucija, nedigitalan oblik podataka i nepotpuno prostorno prekrivanje. ipak, na analiziranim fotografskim snimkama sa shuttle-a kao i na koriπtenim radarskim i satelitskim snimkama izvrπena je analiza lineamenata, te je bilo moguêe vrlo dobro registrirati elemente prstenastog oblika bilo meteoritskog ili drugog podrijetla. uspjeπna identifikacija snimaka s kraterima moguêa je putem mreænih (www) baza podataka i baza podataka na video diskovima. tekstualno pretraæivanje pomoêu kljuëne rijeëi ili geografskog lokaliteta nabræi je put do traæenih scena. tehnike poboljπavanja snimka i pojaëavanja lineamenata su uspjeπno primijenjene na skaniranim shuttle fotografijama. neki morfoloπki elementi te karakteristiëni sustavi pukotina i rasjeda identificirani su na svim snimcima, no rezultati dobi215trenc, morgan, donovan & busbey: remote sensing analysis of selected terrestrial impact craters... veni na temelju snimaka kratera manjih od 2 km bili su bitno slabiji. bolja rezolucija snimaka, njihov digitalni format, te misija posveêena snimanju meteoritskih struktura bitno bi unaprijedili vrijednost fotografskih snimaka sa shuttle-a pri istraæivanju meteoritskih kratera. zahvale ovo istraæivanje ne bi bilo moguêe bez pomoêi slijedeêih organizacija: texas christian university research foundation, nasa, adkins research fund, te lyndon b. johnson space center-a. dr arthur ehlmann (texas christian university) dao je izuzetno vrijedne savjete vezane uz literaturu i stranice na internetu. lt. col. ned fleming i sue runco iz johnson space centra svojom ljubaznom pomoêi omoguêili su ovo istraæivanje. takoer bismo æeljeli zahvaliti dr. ivi veli∆u i prof. dr. marinku olui∆u na vrijednim savjetima i izuzetno korisnim sugestijama. 216 geologia croatica 52/2 petric.indd 171 � ab stra ct for the adequate protection of karst springs it is important to understand the functioning of karst systems in their recharge areas. besides tracer tests with artifi cial tracers, tracings with natural tracers, such as temperature, are a very useful research tool, especially in complex karst systems with various types and sources of recharge. detailed monitoring of water levels and temperatures of the malenščica karst spring, as well as of the intermittent cerknica lake and kotliči spring in its recharge area, indicated that temperature is a good tracer in winter and summer periods, especially when the cerknica karst polje is fl ooded. high or low air temperatures infl uence the temperature of water, which sinks at the cerknica polje and fl ows rapidly through karst channels toward the springs. detailed analysis of selected events enabled calculation of the velocity of groundwater fl ow toward the malenščica spring under different hydrological conditions. the estimated values are in accordance with the velocities previously defi ned in this area, based on several tracer tests with artifi cial tracers. from the results, it is possible to assess the transport velocities of contaminants under different hydrological conditions. this is important information for the protection of the malenščica spring, which is captured for the public water supply. keywords: karst spring, water temperature, recharge, malenščica, slovenia water temperature as a natural tracer – a case study of the malenščica karst spring (sw slovenia) � janja kogovšek and metka petrič karst research institute src sasa, titov trg 2, 6230 postojna, slovenia; (kogovsek@zrc-sazu.si, petric@zrc-sazu.si) doi: 104154/gc.2010.14 geologia croatica 63/2 171–177 6 figs. 1 tab. zagreb 2010 geologia croaticageologia croatica 1. introduction karst aquifers are very vulnerable to various sources of pollution. to protect them properly, it is important to understand the characteristics of groundwater fl ow in their recharge areas. different research methods are used in the studies of karst systems, one of the most often applied methods being tracer tests. artifi cial tracers proved to be very useful in research of underground water connections, but in addition, tracings with natural tracers are becoming a very important tool for the study of the functioning of karst springs. a casestudy of the malenščica karst spring in south-western slovenia is described here, in which water temperature was tested as a possible natural tracer. groundwater temperature can be used as a tracer to reveal the regional structure of a groundwater fl ow system (bonacci, 1997). it is a parameter that carries information on the hydraulic and thermal conditions in the karst interior (genthon et al., 2005). it can be considered as a nonconservative tracer due to the exchanges of temperature between water and rock along the underground fl ow. when recharge water enters the aquifer system and fl ows downgradient through the conduits, the initial temperature difference will decrease due to the heat-exchange at the water-rock interface. the degree of heat exchange is controlled by the thermal characteristics of the rock and the conduit characteristics, such as conduit length, cross-sectional area, and fl ow velocity (renner & sauter, 1997). water tends to geologia croatica 63/2geologia croatica 172 establish equilibrium temperature with the surrounding rock and sediments through conductive and advective processes (dogwiler & wicks, 2005). additionally, in complex karst aquifers, signifi cant changes of temperature under a variety of hydrological conditions are a consequence of the infl ows of water with different characteristics from various parts of the recharge area. in several studies, measurements of fl ow and temperature in karst springs were used to defi ne the physical characteristics of large scale conduits in a karst aquifer (renner & sauter, 1997; hückinghaus et al., 1997; long & gilcrease, 2009). a more detailed study of the heat transport modes occurring in an observed karst aquifer was carried out by bundschuh (1997). relationships between air and water temperatures were used to classify stream-groundwater interactions (o’driscoll & de walle, 2006). the malenščica spring is an interesting example of a spring fed by primary recharge (autogenic), in the karst massif (deep karst water), and secondary recharge (allogenic), along the karst poljes (surface water in the intermittent lake and sinking streams). both types of infl ows mix within the karst system and their contribution to the spring discharge varies according to the hydrological conditions. the aim of the present study was to compare the water temperatures at various locations within the studied karst system in order to assess the relationship between the main contribution areas within the catchment of the malenščica spring under different hydrological conditions. 2. characteristics of the study area the malenščica spring is captured for the water supply of approximately 21,000 inhabitants in the municipalities of postojna and pivka. it is situated at the southern border of the planina karst polje (fig. 1). according to data for the period 1961–1990, its lowest discharge was 1.1 m3/s, with mean discharge of 6.7 m3/s, and maximum discharge at 9.9 m3/s. the recharge area of the spring was defi ned on the known geological and hydrogeological conditions, and the results of tracer tests. its central part is the karst massif of javorniki and snežnik, in which underground fl ow is dominant. the area is composed of cretaceous carbonate rock, mostly limestone. on the eastern and northern sides of javorniki there is a string of karst poljes that are distributed in a se-nw direction, of which the cerknica polje is the largest. the oldest rocks in this part are upper triassic dolomites between the planina and cerknica poljes. jurassic limestone and locally dolomite form the north-eastern boundary of the sequence of karst poljes. quaternary alluvial sediments were deposited on karst poljes. at high water, these are fl ooded and intermittent lakes are formed. at the north-western boundary of the cerknica polje, the cerkniščica and stržen surface streams, which fl ow along the polje, sink and fl ow underground mostly toward the rak and kotliči springs in rakov škocjan. both springs recharge the rak river, which fl ows on the surface for 2 km. the rakov škocjan area is composed of cretaceous limestone, which is covered along the stream with holocene sediments. rak sinks underground again in the tkalca cave and fl ows toward the malenščica and unica springs at planina polje. due to the great extent and complex structure of the catchment, the proportions of the different infl ows change in time with the different hydrological conditions. a variety of geological, geomorphological, speleological and hydrogeological research has been carried out in the described study area. the results improved the understandfi gu re 1: hydrogeological map of the study area. legend: 1. malenščica spring, 2. unica spring, 2a. planina cave-pivka branch, 2b. planina cave-rak branch, 3. tkalca cave (ponor of the rak river), 4. kotliči spring, 5. cave system zelše (spring of the rak river)–karlovica (ponor on the cerknica polje), 6. postojna cave, 7. karst aquifer, 8. fissured aquifer, 9. porous aquifer, 10. very low permeable rocks. kogovšek and petrič: water temperature as a natural tracer – a case study of the malenščica karst spring (sw slovenia) geologia croatica 173 higher than in the infi ltrated water in the karst massif, which reaches equilibrium with the rock temperature at a depth of approximately 100 m. this was proven by long-term continuous measurements of water temperature in the vadose zone of the postojna cave (kogovšek, 2009). in the underground system, these two types of recharge interact, and the temperature at the spring may refl ect the relationship between them. this important infl uence of hydrological conditions should be considered in the interpretation of the data obtained, but we should be aware that some other impacts, which are very diffi cult to detect and explain, also infl uence the characteristics of temperature at the spring. the fi rst systematic observations of water temperature of the malenščica spring were carried out from june 1999 to the end of 2000 using a gealog s logotronic data-logger, and in 2001 with an isco 6700-sonde ysi 600. analysis of the data obtained indicated the important infl uence of the intermittent cerknica lake on the spring, but the lake temperatures were not regularly measured. in order to improve understanding of the functioning of the studied karst aquifer, instruments were installed in 2007 to measure data on the watercourses in the catchment of the spring and its water capture. data was collected on water levels, discharges, electrical conductivity and temperature in 30-minute intervals from autumn 2007 to spring 2009. these parameters were measured with an isco 6700 with the ysi 600 sonde and 750 area-velocity module at the malenščica spring, and with td divers (van essen, a schlumberger company) at other locations. analysis of the temperature and water level data (or discharge) of the malenščica and kotliči springs, were compared with the cerknica lake. data for the latter was provided by our colleague janez turk. air temperature data at the postojna meteorological stations was obtained from the environmental agency of the republic of slovenia. 4. results the comparison between air temperatures and temperatures of the cerknica lake indicated that water temperature reacts ing of the functioning of this karst system. an important proportion of recharge with primary infi ltration on the javorniki massif was proved by tracer test on the poček military training area (kogovšek, 1999). underground water connections between the malenščica spring and the ponors at the north-western border of the cerknica polje, and ponors in rakov škocjan were also confi rmed by several tracer tests (habič, 1987b). the infl ow from the cerknica part of the recharge area greatly depends on the hydrological conditions, which were not registered in the above mentioned tracer tests. in may 2008 a tracer test was carried out with the injection of uranine in a ponor at the north-western border of the cerknica polje (gabrovšek et al., 2010). under the conditions of a relatively stable discharge of the malenščica spring of 6.4 m3/s, the main direction of groundwater fl ow towards the kotliči spring and further toward the malenščica spring was proven. lower concentrations were later detected in the rak branch of the planina cave. the dominant apparent fl ow velocity, (regarding the fi rst peak of the breakthrough curve) toward the kotliči spring was assessed at 109 m/h, and from there to the malenščica spring as 99 m/h. analyses of calcium and magnesium concentrations were carried out simultaneously with the tracer test. comparison of ca/mg ratios of the rak (2.5), kotliči (4.5) and malenščica (6.5) springs indicates an important part of the recharge of the malenščica spring is from the javorniki karst aquifer, which is mainly composed of cretaceous limestone. detailed monitoring of the ca/mg ratios between 1999−2001 (kogovšek, 2004) proved comparable values of ca/mg ratios: 1.6 for rak, 4.8 for kotliči, and 6.5 for malenščica springs for similar hydrological conditions. 3. methods the study is based on the fact that the waters that recharge the spring have different water temperature characteristics. surface fl ows are much more infl uenced by the air temperature and the changes of water temperatures are signifi cantly fi gu re 2: comparison between air temperature and the temperature of the cerknica lake. geologia croatica 63/2geologia croatica 174 to the changes of air temperature with a particular time lag. the best fi t in the comparison of the periods of increase and decrease of temperature was obtained by the calculation of the 10 day moving average of air temperatures, which means that the lake temperature is conditioned by the average temperature of the 10 preceding days (fig. 2). high oscillations of water temperature of the malenščica spring were detected by measurements in the period from june 1999 to december 2001. the highest recorded temperature was 19.2ºc on july 24, 1999, and the lowest 1.7 on january 21, 2001. these extremes were reached in periods when the cerknica polje was fl ooded and with contemporaneous high or low air temperatures (table 1). between 1999−2001, the minimum discharges of the malenščica spring were recorded at the end of august and september (fig. 3). the lowest discharge of 1.97 m3/s was recorded on september 2, 2001, when the water temperature was 8.4 ºc. under such hydrological conditions in the ponors at the north-western edge of the cerknica polje, only a small amount of the cerkniščica river sinks, and the stržen river does not reach the ponors, so the infl ow from the cerknica area has only a minor infl uence on the malenščica spring. therefore the temperature of the spring refl ects primary recharge from the javorniki karst aquifer. at low waters in august 2003 (the spring of the rak river was dry), the ca/mg ratio of the malenščica and kotliči springs was practically the same (approximately 4.5) (kogovšek, 2004). this indicates that under such conditions both springs are mainly recharged from the javorniki area, where more permeable fi ssures and conduits are activated, and their contribution dominates over that from the less permeable parts of the karst system. in august and september 2000, the discharge of malenščica did not fall below 3.28 m3/s, but its low temperature of 8.6 ºc indicates that infl ow from the cerknica area was very low. during low waters in september 1999, when the minimum yearly discharge of 3.41 m3/s was reached, a somewhat higher temperature of 9.4 ºc indicated a more signifi cant infl ow of warmer water from the cerknica area. this was the end of a long, very hot summer period of high waters, which did not occur in the following two years. at the beginning of june 1999 the temperature of the malenščica spring had already reached 18ºc. from june 6 to july 1, 1999, the temperature decreased to 13ºc in conditions of minor oscillations of discharge around 7 m3/s, that indicates the gradual decrease of infl ow from the cerknica area. on july 10, 1999, the discharge started to increase, reached the maximum value above 8 m3/s, remained at that level for 12 days, and then started to decrease (fig. 4). the temperature of the malenščica spring increased rapidly, and even daily oscillations of temperature were registered. the highest temperature of 19.2ºc lasted for 7 hours on july 24, 1999. with a further decrease in discharge, the temperature was also decreasing as a consequence of a reduction of the recharge from the cerknica area and an increased proportion of the contribution from the javorniki karst aquifer. evidently the temperature of the sinking water in the cerknica polje was very high, and further fl ow through well developed karst channels was rapid, so that no signifi cant cooling of a relatively large amount of fl owing water occurred along the underground path. the discoveries described above were additionally confi rmed by observations between 2007−2009. at very low water when the discharge of the malenščica spring decreased toward 2.9 m3/s on march 9 in 2008 (figs. 5 and 6), the temperature of the spring slowly increased, (even though the air temperature and consequently the lake temperature were very fi gu re 3: recorded temperatures and discharges of the malenščica spring from june 1999 to december 2000. dotted line borders a selected interval presented in fig. 4. table 1: minimum and maximum temperatures of the malenščica and kotliči springs occuring during fl oods in the cerknica polje. malenščica spring kotliči spring hydrological year tmax (°c) tmin (°c) tmax (°c) tmin (°c) until 19.9.1999 19.2 (24.7.99) 20.9.1999–30.9.2000 2.3 (26.12.99) 31.9.2000–1.9.2001 14.4 (7.5.01) 1.7 (21.1.01) 4.9.2007–17.10.2008 17.7 (17.8.08) 5.0 (16.2.08) 22.7 (3.7.08) 2.6 (22.2.07) from 17.10.2008 1.7 (2.1.09) 15.3 (17.5.09) 2.0 (5.1.09) total period 19.2 1.7 22.7 2.0 kogovšek and petrič: water temperature as a natural tracer – a case study of the malenščica karst spring (sw slovenia) geologia croatica 175 low), reaching 8.1ºc. this indicates that the amount of infl ow from a very cold cerknica lake was very low. a slightly larger infl uence of the lake was observed in the kotliči spring. a reverse situation was observed in autumn 2008. the temperature of the cerknica lake increased during the summer to 25ºc, and the malenščica spring reached 17.7ºc. in september and in the beginning of october the lake temperature was still above 20ºc, while in the malenščica spring, the temperature decreased to 9ºc, parallel with the decrease of discharge to 1.6 m3/s on october 17, 2008. again this can be explained by an increased amount of recharge from the javorniki karst aquifer. during lengthy fl ood conditions (from march to the beginning of may 2008, and december 2008 to march 2009) the water temperature was very uniform within the observed system (cerknica lake−rakov škocjan−malenščica). water temperatures of the malenščica and kotliči springs were compared in more detail over the short interval from march to april 2008 (fig. 6). in the beginning, the discharges were low and recharge from the javorniki area prevailed in both springs. after precipitation a greater infl uence of the infl ow from the cerknica area was indicated by rapid changes of temperature. the reaction of the two springs is similar, but due to a larger distance and longer path of underground fl ow the changes at the malenščica spring are delayed and reduced. based on the assumption that the velocity of the transfer of temperature along the underground fl ow is considered to be equal to the velocity of water fl ow, the positions of the peaks (maximum) or saddles (minimum) of the temperature curves of the kotliči and malenščica springs were compared. in this way the fl ow velocity in the karst system between the two springs was estimated at 145 to 215 m/h (at discharges of malenščica from 5 to 9 m3/s). these values are comparable with fl ow velocities from 140 to 256 m/h, which were calculated as a result of 5 tracer tests performed in the area between rakov škocjan and malenščica (habič, 1987a). a lower fl ow velocity of 99 m/h was defi ned by the tracer test in may 2008 (discharge 6.4 m3/s, slowly decreasing). unfortunately, only small changes of hydrological conditions and water temperatures were recorded during this tracer test, and it was not possible to accurately defi ne the peaks and saddles of the curves. nevertheless, an approximate comparison of both temperature curves indicates a similar range of velocity as was calculated based on the results of tracing with uranine in the same period. daily oscillations of temperatures, recorded during high waters in the beginning of april 2008 (fig. 6) are interesting. they were very regular at the kotliči spring and slightly less distinctive at the malenščica spring. the comparison of fi gu re 4: temperatures and discharges of malenščica spring for a selected interval in the summer of 1999. fi gu re 5: recorded temperatures and discharges from sep tember 2007 to april 2009. dotted line borders a selected interval presented in fig. 6. geologia croatica 63/2geologia croatica 176 their position confi rms the characteristics of groundwater fl ow in the rakov škocjan-malenščica karst system as described above. on july 21, 1999, the temperature of the malenščica spring (discharge 8 m3/s) was 17.8ºc, 21.5ºc at kotliči, and 23ºc at the cerknica lake. supposing that the temperature of the infl ow from the javorniki karst aquifer is 8.5ºc (based on the measured temperatures at malenščica at very low discharges), we assessed the amount of recharge from the cerknica area in the malenščica spring to be up to 70%. similar assessment for the end of december 1999 (discharge of malenščica approximately 10 m3/s) resulted in calculation of an even higher amount. in march 2008, the temperature of the cerknica lake was 5.4ºc, and the malenščica spring was at 8.1 ºc (discharge 3 m3/s). this indicates recharge from the cerknica area at approximately 15%. such calculations can give us a general idea about the different contributions to the recharge of the malenščica spring, but as they do not take into account the changes of water temperature along the underground path due to the exchange with surrounding rock, they are only rough estimations. 5. conclusion propagation of temperature signals through the underground system in the catchment of the malenščica spring was analysed under different hydrological conditions. the results obtained indicate that temperature is a very good natural tracer of water fl ow in the study area of a very complex karst system, with well developed karst channels, especially in winter and summer periods when the cerknica polje is fl ooded. minimum and maximum temperatures of the spring were recorded in the periods of high water (dominated by recharge from the cerknica area) and very low or high air temperatures. during low waters the recharge from the javorniki karst aquifer prevails. a detailed analysis of selected water waves enabled calculation of the velocities of groundwater fl ow toward the malenščica spring for different hydrological conditions. velocities obtained are comparable with those calculated on the results of tracings with artifi cial tracers. information about the fl ow velocities at different hydrological conditions is important for the protection of the springs captured for the water supply, because it enables assessment of the characteristics of the transfer of contaminants which differ signifi cantly according to the hydrological conditions. one of the main sources of pollution in karst areas is waste water from urban areas. in the settlements on the cerknica polje, sewage water is only partly cleaned in an old water treatment plant with insuffi cient capacity, and it endangers the quality of the malenščica spring. although some interesting results were obtained by the research described here, the limitations of the research tool should not be disregarded. in order to verify and improve the findings we applied other research methods in the malenščica study area, and the data obtained will be used in further studies. references bonacci, o. (1987): karst hydrology.– springer-verlag, berlin, 184 p. bundschuh, j. (1997): temporal variations of spring water temperatures in relation to the extents of the heat transport modes occurring in the karstifi ed lower gypsum-keuper aquifer (karnian, southern germany).– in: jeannin, p.-y. (ed.): proceedings of the 6th conference on limestone hydrology and fissured media, la chauxde-fonds, switzerland 1997, 129–132. dogwiler, t. & wicks, m.c. (2005): thermal variations in the hyporheic zone of karst stream.– speleogenesis and evolution of karst aquifers, 3, 1–11. gabrovšek, f., kogovšek, j., kovačič, g., petrič, m., ravbar, n. & turk, j. (2010): recent results of tracer tests in the catchment of the unica river (sw slovenia).– acta carsologica, 39/1, 27−37. genthon, p., bataille, a., fromant, a., d’hulst, d. & bourges, f. (2005): temperature as a marker for karstic waters hydrodynamics. inferences from 1 year recording at la peyrére cave (ariège, france).– journal of hydrology, 311, 157–171. habič, p. (1987a): raziskave kraških izvirov v malnih pri planini in zaledja vodnih virov v občini postojna [study of the karst spring in malni near planina and catchments of water resources in the municipality of postojna – in slovenian].– unpubl. report, karst research institute, postojna, 58 p. habič, p. (1987b): water tracing test on the karst watershed among idrijca, vipava and ljubljanica.– acta carsologica, 16, 105–118. hückinghaus, d., liedl, r. & sauter, m. (1997): characterization of karst aquifers by heat transfer.– in: jeannin, p.-y. fi gu re 6: recorded temperatures and discharges for a selected interval in the spring 1999. kogovšek and petrič: water temperature as a natural tracer – a case study of the malenščica karst spring (sw slovenia) geologia croatica 177 (ed.): proceedings of the 6th conference on limestone hydro logy and fissured media, la chaux-de-fonds, switzerland 1997, 145– 148. kogovšek, j. (1999): new knowledge about the underground water drainage in the northern part of javorniki mountains (high karst).– acta carsologica, 28/1, 161–200. kogovšek, j. (2004): physico-chemical properties of waters in the malenščica recharge area (slovenia).– acta carsologica, 33/1, 143–158. kogovšek, j (2009): characteristics of water fl ow through the karst vadose zone.– unpubl. phd thesis, university of nova gorica, 215 p. long, a.j. & gilcrease, p.c. (2009): a one-dimensional heat-transport model for conduit fl ow in karst aquifers.– journal of hydrology, 378, 230–239. o’driscoll, m.a. & de walle, d.r. (2006): stream-air temperature relations to classify stream-ground water interactions in a karst setting, central pennsylvania, usa.– journal of hydrology, 329, 140–153. renner, s. & sauter, m. (1997): heat as a natural tracer: characterisation of a conduit network in a karst aquifer using temperature measurements of the spring water.– in: günay, g. & johnson, i. (eds): karst waters & environmental impacts, balkema, 423−431. manuscript received december 23, 2009 revised manuscript accepted february 25, 2010 available online june 28, 2010 geol. croat. 50/1 49 · 56 6 figs. zagreb 1997 the helicoidal fault systems of vinodol (croatia) and their genesis ivan blaskovic key words: helicoidal raull sys tem, genesis of faults, en echelon rolds, f'ault s impact 011 hydrogeology, vinodol , croatia. abstract the basic geological fca!urcs of (he he licoidal fault systems of ihe vinodol arc:l atc outlined. [i s genes is is explained by a model proposing colli sion:l! stress implied on prev iollsly formed en echelon folds. the importance of ihe fault system fo r struc tura l and palaeo­ geographic reconstruction as we ll as it s impact on hydrogeology are di scussed. the model could be applied 10 the external dinaridcs or to olile r similar sys tems. 1. introduction by analyzing the geological and especially structu ­ ral relationships of the vinodol area se of rijeka (mostly encounte red along the north-eastern rim of the va lley) fault sys tems o f variable morphologic and kine­ matic features that change along the ir strike and dip are recognized. most or the northeaste rn rim or the v inodol valley is composed of upper cretaceous rudist limestones, transgressive ly and disco rdantl y overlain by palaeo­ ceneeocene foraminiferal limestones. the valley itself is built up by the eocene fl ysch sedi ments (grimani e t ai., 1973). the rim-va lley trans ition , i. e . the lime­ stone-flysch eonlaet is marked by two or more fault traces that by the ir kinematic fun ction along the strike merge into reverse or even overthrust st ruc tu res. the sam e fault s associated with inclined , overturn ed and isoc linal synclines or sw vergence can exp lain th e loca l, deep underthrusting of the nyseh sediment s (fig. i ) . within the described structural selling the complete ra id structures are only partly preserved: synclines, as the footwall of the reverse faults, with fl ysch occupying the ir cores have subsided and thus became less exposed at the surface, while th e limestone anticlines, as the hanging wall , arc uplifted and have bccom e more extended. the fault traces arc ensily recognisable al ong their strike as the line of the carbonate-flysch contact. rn casfac ilit y of mi ning. geol ogy :wd pet rolell m engineering. uni versity of z lgrcb, pi cro tlijev a 6, iir i 0000 zagreb, croatia. kljucne rijeci: sustav helikoida lni h rasjeda , geneza rasjeda, esalonirane bore, hidrogeoloska uloga rasje­ da, vinodol, hrvatska. saietak na primj cru iz vinodota dat j e prikaz karak lc ri s tika sus lava hcl ikoid alnih rasjeda. modclom je prezenliranh gc llel.a sus tava, vezana uz dje lovanje ho ri l.o ntalnog s trcsa na prv olllo formirane c~a t oniranc bore. tslakn uto je znaccnjc rasjcdnog s lis lav (l u st ruk ­ turnoj i pa lcogeogra fs koj rekons ltukc iji , kao i u h idrogeo lo~k im islrazivanjima. prczentirani modcl moze .~c primjcnili u vanj skim dinaridima a i sire. es when the faults strike farther into the carbonates their presence is much less obvious. however, they can a lso be identified by the truncation and offset of a transgres­ sive contact between the rudist and foraminiferal lime­ stones or by som e geomorpholog ical indicators , the most frequently by linear arrangement of s inkholes in the carbonate terrain. 2. the helicoidal fault systems ofvinodol generally , the faults can be de fined as convergent splays that joint the main fault (fig. 2). in the ir margin­ al part splays strike nnw-sse, more or less separated , predominately with oblique strike-slip and possibly nor­ mal movement. the peculiarity o r the fault s or the system is the he li ­ coidal shape or each individual rault plane (i'iarding , 1983; naylor e t ai. , 1986; sylvester , 1988). along the strike, the azimuth or dip c hanges as the angle of dip gradually changes. an examp le of the fault systems used to create the model is shown in fig. 3. close to the conn ec tion point the fault planes become more inclined and beeome vertical while along strike the dip changes in the opposite direction. conse­ quently, th e normal sensc of movem ent bccomes reverse combined with an oblique slip component. the strike gradually becomes "more dinaric" in orientation, typically nw-se. thus, the main fault plane shows a relatively low angl e of dip (up to 25°) with a marked reverse character and could poss ibly pass into an over­ thrust strue turc . the vergence o r reverse and thrust faults corresponds with thc sw vergence of the fold s. ,0 le gen d " ~ m 2 lienl 3 geologia croalica 50/1 4 b( 11 fig. 1 index and genera lized geological map of !he vinodol area (a fter ~usn j ar ci ai., 1970; simpli f ied and part l y modified). legend: 1) upper cretaceous limesto nes and do lomites; 2) palaeogene fo raminifcral1imesloncs ; 3) palaeoge ne tl ysch; 4) normal contact, ullconfol"jll i­ iy: 5) strike-s lip faull: 6) reverse fault; 7) upright, incl ined, ovcr!llrtlcd illll icl ine; r) upright, inc lined, ove rt urned !iynclinc: 9) monocl ine; [0) strike and dip of bedding wilh 25_35° and 50-75° angle of dip: ii) overturned bed. si. i smjcslajna i shcmatska gco[oska karla vinodo la. shemalsld prikaz gco!oskih odnosa 11 <1 d ijclll sjcvcroistocnog obocla vinodola s posebno islaknulim uzd uzni rn rasjcdima (prcill41 susnjar et ai. , 1970, pojcd nos lav ljcno i dijclom dopu njcno). legcnda: i) gornjokredni vapnenci i dolomili; 2) palcogenski fo mm inifcrski vapncnci; 3) palcogcnski n isni sed imcnt i: 4) normal na granica, icklonsko-crozijska d iskonlancija; 5) horizon!al ni msjcd: 6) rcvcrzni rasjed: 7) usprav na, kosa, prcbacena an!ikli nala; 8) tlspravn:l, kosa, prebaccna sink linala: 9) koljcnieas!(t bora, tlcksura: 10) polozaj srojcva; vclici n<l nagiba 25-35°, 50_75°; 11) prc baccni sloj. legend ini!!!!!i:h flysch d limestones conditional orientation not in scale the genes is o f the described faull system li es in quite complex tec tonics and g reat differences in the gcomechanical p roperties of the carbonate and clast ic sedimentary bodies. it could be explained by a succes­ sion of geodynami c processes and presented by a con­ ceptual model as follows. the geodynami c evolut ion begins with the larami ­ an deform alion phase that res ulted in the formation of en echelon folds (fig. 4) and the consequen t morphol o­ gy. furthermore, during thc pre-pyrenean and pyrenean deformation phases the anticlinorian parts o f the struc­ tures consisted of predominately of carbonate rocks and the synclinorian parts of fl ysch clasti cs. the thi ckness of clastics is direc tly related to the synform , as one part fig. 2 schelll ilt ic di agram showing iwo systems of convergenl he li· coidal faul ts in the ne rim arc'i o f vinodol. $1. 2 shem<llski prikal dva sustava konvergirajllci h hcli koidalni h ras­ jcda 1i istra:zi vanorn d ijclu sjeveroistocnog oboda vinodola. bi:l.~kovic: the t !clieoidnl fnu h systems of yinodoj (croatia) and their genesis ~ n ~ condit ional orlentlltlon not scalelegend 51 fig. 3 schematic plan view of convergent he!i coidul fault planes with the great est principal stress orientation. a, b, c as reference observation points for the second deformation phase (sec fig. 6). s1. 3 shematski ortogonalni prikaz konvergirajllcih helikoidalnih ras ­ jednih ploha s naznacenoitl orijentacijom glavne osi stresa. a, b, c, referentne tocke razmat ranja ii drugoj fazi strukturnih promje­ na (sj. 6). of megastructure characterized by greater mobility and subsidence rale. even with more intens ive folding during the pro­ gressive deformation process the mobility of the syn­ forms and particularly the flysch thickness arc of cru­ cial importance, i.e. the amplitudes of folds are directly related to the thickness of the less competent, clasti c sediments. under the same stress field regime tha t regionally resulted in the continen tal subduction of the adriatic under the dinaric (herak, 1980; blaskoyic & allinoyic, 1981; blaskoyic, 1991 ), the structur­ al changes are partially govemed by the clockwise rota­ tion of each individual fold around the "b" axis (fig. sa): the anticlines, as the more rigid , competent parts conditional orienlation not in scale a a 1 d 2 il:!m[n~ 3 ~/:;. 4 ~ e-w 5 _._-6 _w. 7 1--1' 8 fig. 4 the genesis or the helicoidal fault syslem: a) pres umed originallcclonic fabric of wngelliial folded structures; b) collisio nal stress impl ied 011 ell echelon folds: c) imbricate structure and convergent helicoidal fault splays . legend: compelcnt rocks: i) upper cretaceous rudis i ii llles ione; 2) eocene foraminifera limes tones. incompetent rocks : 3) eocene flysch. 4) principal slress orientation: 5) upright, inclined and oven urncd anticlin e: 6) predetermined faull zones; 7) nonnal and reverse fault: 8) irace of schematic geological profile. si. 4 pos tanak sllstav<l hclikoidalnih rasjeda: a) prelposlav lj eni polazni tektollski sklop langencijalnih boranih st ru ktura; b) esa lonirane bore izlozene horil',onlalnom strew: c) ijuskave siruklllre i konvergirajuci snap helikoidalnih rasjeda. legellda: kornpetentnc stijene: i) gornjo­ kredni rudisllli vapnenci i 2) eoccnski foraminifcrski vap nenc i; nekompelentne stije ne: 3) cocenski flis. 4) orij cntacija glavnog slrcs a: 5) uspravnit, kosa i prebaccna ;lil1ikl inal a; 6) prcdisponirane zone rasjeda: 7) rasjcd normalnog, revcrznog karaklcra; 8) irasa shcmatskog geo lo.~kog profila . geologia croatica 50/1 i. ai, "1("-__ _ ci.~~ -r--8w ne ilitrt~'"i ... 1 ii: i 1 ii: ~4.. __ _ -r--fig. 5 prc!'cntation of !'tnlctural changes on schcmatic geo logical profiles, an <lddi\ ion to fig. 4. a) en ec hclon fo lds from fig. 4b. due to bend ­ ing o f presumed mega .~ t fuchire (fig. 4a) thc axial planes and fold limbs changc iheir strike and dip: b) the result of the fi rs t deformation phase: imbricate structures o f variable de formation intensity with faults merging into the main fault zonc. symbol ex planation as for fig. 4. s1. 5 praccnje slruklurn ih promjena na shematskim geoloskirn profilima, dopun<l sl. 4 . a) borane strukturc csa lon iranog rasporcda sa sl. 4b. oponasajllcl zakrivljenost pretposlavljcnc mcgastrllktlll'e (sl. 4a) bore mijcnjaju c lemente polozaja o!'nih ravnina i krila. b) rezultat djclo­ vanja gcncralnog !'tresa i olpora istomc u prvoj fazi slrllktllrnih prornjcna: iju skave struklure nizli cilog ilhenzilcla porcmecaja liz slapanjc rasjcda ii jed inslvenu rasjednu zoiiu . zn:lccnjc simbola vidi 1i polpisli 51. 4. (regarding lheir structural form and predominance of carbonate rocks ncar the surface) are uplifted whi le the synclines, as the more mobile parts ( regarding the ir negative fo rm and predominance o f clastics) tend to subside. thi s results in brittle failure within th e folds inflection zones and thus in the [ormation of fault s (fig. 5a). within parts of en echelon fold s dominated by anti­ cl ine structures characteri zed by the more rigid carbon­ ate rocks, the developed fa ults are partially of normal lype and with vertical fault planes. therefore the reduc­ tion of width of the original en echelon structurc due to faulting is minimal (figs. 4e, 5b, prollie e i-i'). in con­ tras t, within the parts o f en echelon fo lds dominated by sync linal structures characterized by predominance of the thi ck, less competent clastics, the developed j~\lllt s are o f a reverse type with fault planes that dip in the direction of the main coll is ional stress, i.e. wi th struc­ tures showing opposite vergencc (figs. 4b, sa, profile b ii-ii'). as the anticlines pl un ge and turn into a uniform gross synclinal st ructure the reverse fault s merge into a s ing le ma in fau lt that could possibly become an over­ thrust structure (figs. 4c, 5b, profi le c ii-ii '). the reduc­ tion of width of the origi nal en eche lon structure is maximal: the synclinal structures , the thickness of the clastic compl ex, as well as the deepe r pos ition o r car­ bonate rocks reduce the resistance to the main coll is io­ nal stress. the transition between the described end cases is gradati onal regarding the character and shape o f the developed structures as we ll as to the intens ity of the deformation. the first phase of the geodynamic process thus results in the formation of a system or convergent heli ­ coidal faults (fig. 3), and in modified en echelon imbri­ cate structures, that mark the structural fabric in general (fig. 4c). the strike of the imbricate structures changed in respect to the st rike of the axial planes of the orig inal en echelon folds. in the process of the rollllation of the imbricate structures and the convergent splay of heli­ coidal fault s, respecti vely, the reeluction of the origi nal width resulted in bcnd ing of the strike lincs. thi s change in strike is only local duc to specific conditions and not due to change in the regional o rientation of the main collisional stress direction, as is shown on the pre­ sented mode l. the nex t deformation phase or the geodynamic process is marked by a relative change in the stress field orientation (anderson & jackson, 1987; ritsema, 1974) with a generally n-s to nnw-sse orientation of the greates t principal stress ax is, i.c. diag­ onally to the dinaric strikc of the structures. alt hough thi s change in orient ation was gradual we shall discuss here and schematically present only the youngest de for­ mational phase. the prev iously formed faults in the marginal part of the convergent splay of the he lico idal system , stri ke b1as~o\lic: the i lclicokial ewh systems of vinodol (cro;lti., ) ,hid their genesi~ 53 legend : ~ d n ~ llillilll 2 conditionol of 11m tat ion ¢= no l scale 3 , 4 b 5 6 -7 --0 8 fig. 6 the strucillral deve lopment in the sccond phase of the geodynamic process due to the regional change of stress fi eld orientation: the development of tile transtcnsion zone: the impact or structu res to hydrogeology. legend: t) karstified carbonate rocks permeable rocks: 2) fl ysc h sedimcnts impermeabte rocks: 3) stress fi eld orientation: 4) fau lt s willl ihe se nse or di splacemen t predetermined groundwate r flow conduits: 5) transtension zones, i.e. zones of ex lension fractures: 6) the transpression zones relative barri cr to groundwtller now: 7) supposed groundwater flow direction: 8) potential spring occurrence. si. 6 ova sluc:ija slruktu rnih promjena druge faze gcodi namskog procesa u uvjctima promjene smjcra gcncralnog stres;!: fonniranje ekstenzi­ jski h zona: naznaka hidrogcoloskc uloge formiran ih st ruktur:.!. legenda: i) okrsenc vapnenacke st ijenc propusnc slijcne: 2) ni sni sedimenti ncpropusne stijcnc: 3) orijentacija slresa: 4) rasjedi s oznakorn krctanja hila priv ilcgirani pravci krctanja podzcmne vode; 5) zone ekslen7ij ... kih karaktcrislik a zjapcce pukotine: 6) zone komprcsijskog karaktcm rclaliv ilc barijcre krclanja podzemnc vode: 7) prelpostavljeni ~tlljcr kretanja podzcmnc vodc: 8) moguci izvori. almosi para ll c l with the greates t pr inc ipa l s tress ax is (figs. :) and 6). t hus, the dextra l st ri ke-s li p and oblique-slip di splacement s predominate. the magnitude of di splaceme nt is direc tly re la ted to the mass or eoi11pe tent, ri g id blocks bounded by fau lls of the sys tem as well as 10 the volume of the claslic nyseh complex of the tec tonically reduced syncli na l struclure. the dexlra l s lrike-s li p displacemellls along subpar­ a ll e l fau ll planes of ihe convergent splay of the hel i­ coidal syslcm lead 10 the deve]opmclll of a transtension zone (ramsay & h ub er, 198 7) with ex te ns ion fraclures (fig. 6). t his is pa rt icularly wel l developed with in ihc competent carbonate rocks even in cases whe n ihese arc overla in by clas t ic fly sch sedi ments. these fract ures call rarely be seen o n the surface as they become partia lly fi lled and hidden, due to grav ila­ lional collapse and roek rail. the imporl ance o f the described in terp re ta tion o r the he li co idal fau lt sys tem is man ifo ld . it coul d be applied to resolv ing structural prob lems and genesis o j' termines charac te ri zed by tangentia l tec to ni cs, e .g. in the ra idthrust be lt s. moreover, one can c learly rea lise the poss ibility for pal aeogeog raphi c an d pa linspas ti c reconst ruction as well as for studyi ng structura l changes duri ng the geodynamic process by app ly ing the reverse method of study to the onc described above. t he pa rti cu lar importance and in flu e nce of he li­ coidal rault sys tems on hyd rogeology shou ld be a lso emphas ized (fig. 6). t he faull con tac t be tween the car­ bonate and clastic complex is also the conlac i be l ween permcable and impermeabl e rock unit s; the imperme­ ab le cl astics ihat arc mostl y fau lt bounded flysc h wedges, represent hanging barriers thai ex te nd re lati ve­ ly deeply undergroun d, th us clearly de term inin g ihe ve rt ica l and hori zonta l groun dwa ter now. however, even the fault s of the helicoida l sys tem thai s tri ke in to the carbonat e rock comple x p lay an importa nl ro le in the gro undwate r n ow reg im e: the prede term incd groundwate r fl ow d irec ti ons co uld be expec ted along these fa ult zones. furthe rmo rc, wit hin ihe transtension 54 zone wi th abundan t extension fractures developed in the carbonate rocks massive development of cave sys­ tems could be expected as well as the occurrence of springs of the greatest discharge. 3. conclusion the helicoidal fau lt systems of vi nodol represent convergent splay fau lts that j oint into the main reverse fault. they cou ld be particu larly important in regions characterized by compressive tangential tectonics, i.e. within the [oldth rust belts. they have the ir orig in in deformation induced by coll isional stress imposed on previously formed en echelon folds composed mostly of competent and incompetent rocks. the most recent structural fabric was produced by a relative change in the stress field orientation that resulted in the predomi­ nance of strike-s lip displacements along the faults of the system. during the next deformation phase the formation of extension fractures in competent rocks could be expect­ ed due to transtension developed at fault bcnds. regarding their particularly marked impact on karst hydrogeology the faults of the helicoidal sys tem whether deve loped in permeable strata, or along their contact with impermeable rocks, could be predeter­ mincd to serve as the main groundwater flow conduits. within the transtension zones developed at their bends they could result in the occurrence of karst springs of the highest discharge values. the described model could be app lied in reg ions of simi lar geology, e.g. throughout the external dinarides, or fur ther afield. geologia croatica 50/1 4. references anderson. h. & jackson, j. (1987): active tec­ ton ics of the adriatic rcgion.geophy. j. r. astr. soc., 91, 937-983. blaskovic, i. (1991): raspored uzduznih. reversn ih i norma lnih rasjeda i konstrukcija oblika i dubina ploha podv lai'enja.geol. vjcsnik. 44, 247-256. blaskovic, i. & aljlnovic, b. (198 1): m ikrotek­ tonski elementi kao os nova za mode l tektonske grade sircg podrucja kvarnera.zbornik radova simpozija "kompleksna naftnogeoloska problema­ tika podmoija i priobalni h dijelova jadranskog mora", split, 1,87-100, zagreb. grimani, i., susnjar, m., bukovac, j., mi­ lan. a .. nikler. l., crnolatac, i., sikic, d. & blaskovic. i. (1973): osnovna geoloska karta sfrj 1: 100 000. tumai' za lis t crikvenica l 33-102.inst. geol. istraz. zagreb (1963), savezni geol. zavod beograd, 47 p. harding. t.p. (1983): divergent wrench fault and negative flower struct ure. andaman sca.in: bal­ ly, a.w. (ed.): seismic expression of structural styles, volume 3. am. assoc. of petr. geol. studies in geology, ser. 15,4.2.1. -4.2.8. herak. m. (1980): sustav navlaka izmedu vrbovskog i dclnica u gorskom kotaru (hrvatska). acta geo­ logica, 10/2, 35-51. zagreb. na ylor, m.a .• mandl, g. & sijpesteijn, c.h.k. (1986): fault geometries in basement-induced wrench faulting under different initial stress states.­ jour. struet. geol.. 8. 737-752. ramsay, j .g. & i-luber, m. 1. (1987): the tech­ niques of modern structural geology, vol. 2.acad­ em. press. london, 309-700. ritsema, a.r. (1974): the earthquake mechanism of the balkan region. undp projekt r. 3 em, 70/172. unesco, skopje. sylvester, a.g. (1988): strike-sl ip faults.geol. soc. am. bull., 100, 1666-1703. susnjar. m., bukovac, j., nikler, l.. crno­ latac, i., milan, a., sikic, d., grimani, i., vullc, z. & blaskovic, i. (1970): os novna geoloska karta sfrj, 1: 100.000, list crikveniea l33 -101.inst. geol. istraz .. zagreb (1958-1967), savez. geol zavod beograd. i3h;;kovic: 111c llelicoidal fault systems of vinodol (croatia) and their genesis :i5 sustavi helikoidalnih rasjeda u vinodolu i njihov postanak ivan illaskovic 1. uvod islraz ivanjima geoloskih i posebno slruklurnih odnosa u po cirllcj ll vinodola, locnijc sjeveroi slocnog oboda doline, lllvrdeni sll sll slavi rasjeda razlicilih karaklcri slika, koje sc mijcnjaju po prllzanjll i nagibu rasjednih ploila. sjcvcroi slocni obod vinodola izgraden je pre tez ito iz go rnjokrcdnih rlld islnih i pajeocensko-eocenskih foramini~ ferskih vapnc naca. oni su mcdllsobno ii iransgresiv nom , disko rdanlllom kon laklll . samu dolinll izgraduju eocenski f1i sni scdi mcnli (ortm an i el ai. , 1973). kolllakl izmedu vapnenac<i oboda i f1i sa dol ine je ra5jedan i nijejedinstven; sastoji se iz 2 iii vise rasjeda koji se u pruzanjll i funkciji slapaju u reverzne odnosno navlac nc slruk lurc. uz kosc, prcbaccnc i izoklinalnc bore, tocn ije s inklinalne dijelove lih bora , jugozapadne vergencije, upravo navedcnim rasjc­ dillla moze se objasnili mjestimi cc d uboko uvlace njc rji snih scd imcnala (s l. 1). u takovim slruklurnim odnosima bore su fraglllenlarno sac uvane; s inklinalni dijclovi izgradcni iz fli snih nas laga s li rasjcdi ma rcdllc irani , odnosno nalaze sc ii poclinskim krilima revcrznih rasjcda, dok vcc ll povrsinll imaju anti ­ klinalni dijclovi bora, izgradeni iz rig idn ij ih vapnenack ih st ijena. oni s u u krovinskilll krilima istih rasjeel a. rasjcdi slt vrl0 lioc lj ivi lt dijc lu prolczanja gdje ivo rc kon tak t izl11cdu karbonatn ih slijena oboda i oisnih naslaga; pruz;'ljuci sc u nastavku i unutar vapncnackih slijena oboda vinodola vrlo sc lesko zapazaju, osim prek idom i ira nslacijom iransgrcsivne granice izmeelu rud isln ih i roraminircrsk ih vapncnaca iii indirckln im geomorfo loskim po kaz<llc ljim:l , najcesce nizom ponik vi ii pra vocrt no m rasporcelll. 2. susta vi helikoidalnih ras.jeda u vinodolu op is<l ni sustavi se illogu gcncralno dcfinirali kao kon­ ve rgenlni snop rasjcda koji se spajajll ii rasjccl s jeclin­ slvcnom rasjcdnom ploholll (s l. 2). u perifc rn ojl1 d ijel u snopa, mcc! usobno vise iii manje uda ljc ni, llg lavnolll s u pruzanja nnw-sse, hori w ntalnog oclnosno d ijagonalnog, pa i illogllce no rmalnog krelanja krila. posebno~t rasjcda koj i c ine suslav jc hcl ikoiclalni obl ik ,.asjcdnih ploha (hardi ng, 1983; naylor cl ai. , 1986; sy lvest er. 1988) po pruz<lnju; uz poslllpnll promjcnu ve lici nc nagiba mijenja sc i smje r nag iba. modc lski obradlljllc i jedan od slls lava 10 je i prczcnlirallo na sl. 3. pri blizavajuci .'ic mjest ll s pajanja, rasjcdne plohc sc llslnnljllju sve do oko milog polozaja, a icluci clalj e po pruzanju z<luz imajll s liprotan smjcr nagiba od polaznog; karakt c l' ra sjcdanja postajc rcvcrza n li z dijagonalno i clominiln tllo vcrlikalno krctanje kri la . mijenja sc pruzanjc rasjccla it .wc izrazcniji dinaridski pravac (nw-se). spojeni sno p rasjcda u rasjed s jcdinstvcnom rasj c­ dnom ploholl1 rc lativno blazcg iii blagog nag iba (najvi sc do 25 °), oznacen je izrazitim rcverznim karakterol1l i s l1log 11 c im prijelazom ll struklllrll navlakc. vcrgencija reverznih iii navlacnih slrllktura ide ntic na j e vc rgcilciji bora ij. prcma jllgozapadu. postanak takovih rasjednih suslava jc rczultat s lozenog te ktonizma i geomehanickih karaklcri slika karbonatnih i klaslicnih sedimentnih kolllpjcksa koji izg radlljll ie stru ­ kture. moze se objasniti odrcdcnim sljcdom gcod inamskih procesa, kako je 10 modclolll i licinjcno u nastav ku . oeod inamski razvoj zapocinjc laramijskim pokrelima. pod uljecajcm horizonta lnog stresa i o lpo ra is lom , formi­ raju sc borc csaloniranog rasporeda (sl. 4) i konsekventne l11orfo logije. u nastavk u procesa, u predpirencjskoj i pirc nejs koj faz i geodinamskih promjcna, prctpostav ljajll sc an li klinori­ jski dij c lovi struktura s ciominacijol1l karbonalnih stijena te s inklinorij ski dijelovi ii kojima s ll isla lozcnc fli sne klast icne stijene vecih debljina. i ovclje se deb ljina klast ita veic uz sinformu , kao clio megaslrukt llre vecc l1lobilnosli tij ckom scdimentacije, li smis lu subs idell c ije. no i li geodinamskom p roces il cjaljcg, inlcnzivnijeg boranja kojc slj cdi, mobilnost sredine, a posebno deb ljina fl isa je od pre.suclne vaznosti ; amplitude bora su u izravnoj ovisnost i i 0 dcbljini plaslicnijih scdimcllata. u n<lstavkll dje lovanja horizonlalnog siresa, a koji ii regionalnim okvirima dovodi do podvlaccnja s llbdukcije konlinclltalnc korc adrijatika pod di narik (her ak, 1980; blaskovic & alji nov ic, 1981; blaskov ic, 199 1) strukturne prollljcnc s u odraz d ijc lo m i rolac ije svakc od bora oke b osi (s l. sa); antik linalc kao rig icl niji, ko rnpelc ntniji dij c lovi, s o bz irom na strukl llrni oblik i dol1l inaciju vapnenackih slijcna, blize povrsin i se izd iz li , a sinklinale kao l1lobilniji dije lovi bora, s o bz irom na ncga­ livnll forl1l11 ie clominac iju klastila, tcze sp us lanju. to rczultira plicanjem ii zoni prcgiba bora tj. infl cksijc i ras ­ jcdanjclll (5 1. sa). u dijclovima csaloniranih bora, u koji ma c10llliniraju antiklinalnc st ru klure, s islaknlllijo lll povrsinom i kine­ lllatskom ulogom rigidne kompetcnlnc vapncnacke slijene, rasjcdi sll dijelom i normalnog karaklc ra i s vc rtikalnim rasjed nilll p lohama. redukcija s iri nc pril1larnog csa loni ­ ranog stru klurnog skt opa ll siijed rasjedanja jc minimalna; horizontal nom st.resu suprotstavljen jc odgovarajuc i olpo r, kao rezu ltal antiformnih struk tura i ri gidnijih kompleksa sl ijcn" (s l. 4c i, 5b, profil c 1. 1'). nasuprot tome, u d ijelovima csalo niran ih bora 1i koji­ ma dominirajll sinklinalne slrllklurc s vecom povrsinom i dcblj inolll fli snih naslaga, podatnijih de formacijam<l, rasje­ d i cc bili reve rznog karaktera, s rasjcdnim plohama nag nll ­ l im ll smje ru g lavne osi slrcsa, od nosno sa st ruklllrama sllprolne vcrgcnc ije (sl. 4b i, sa, profil b ii ii '). buduci da ccla anliklina la tonu i prclaze u jcd instvcllll s inklinalnu struklllru, dojazi do stapanja rcvcrzilih rasjccla ii j ed instven i rasjed s mog ll cnosc ll njegovog prijc laza u slrukturll navlake (s l. 4c i; s l. 5b, prori l c ii ii '). rcdukc ija s irin c primarnog ciialoniranog sk lopa jc maksimalna; 56 sinklinalne slruklurc i debljina klaslicnog kompleksa slije­ na, ie dublja pozicija vapncnack ih st ijcna u podini, sllla­ njuju olpor glavnolll kolizijskolll slresu. prijelaz izlllcdu opisana elva krajnja sl ucajaje postupan s obz irom na karakter i obl ik struklura, kao i intenzitet poremecaja. rczultat opisane prve faze geodinamskih proccsa prcd­ slavlja /"ormiranje kollvergirajuceg snopa sustava heli­ koidalnih rasjeda (sl. 3), odnosno u opcelll struklurnolll sklopu modirieiranih, takodcr ciialoniranih ljuskavih stru­ ktura (sl. 4e). pruzanje ljuskavih struklura promijenjeno je u odnosu na pruzanje osnih ploha ishodisnih esaloniranih bora; u proccsu form iranja ijuskavih struktura, odnosno konvergclltnog snopa hclikoidalnih rasjcda doslo jc do povijanja pruzanja kao rezultat redukcije s irine . takova promjena prllzanja je, kako se iz prezenliranog modcla vidi, tck lokalna pojava vezana li z speeiricne llvjele, a nc posljediea promjene smjera glavnc osi slresa. iduca faza geod in amskih proccsa oznacena je rela­ tivnom promjenolll sllljera slresa (anderson & jack­ son, 1987; ritsema, 1974); sires jc usmjcrcn prema sjcveru odnosno sjeversjcvcrozapadu, dijagonalno na dinaridsko prllzanjc struktura. do te promjcne dolazi pos­ tupno, medutim, ovdje se shematsk im prikazolll komentira najmlaela faza. tako orijenlirani stres gotovo je paralelan pruzanju rasj eda na per ifernom dijelu konvergentnog snopa koji ivore helikoida lni sustav (s1. 3 i 6). pod njegovim lltjeca­ jem oelvija se dijagonalno pa i horizonlalno krctanje krila rasjcda; uglavnolll jc to desno kretanjc. velicina hoda jc ovisna 0 !nasi kompclenlnih, rigidnijih rragmenala izmedu rasjeda sustava i islovremeno 0 povrsini i debljini klaslicnog rlisflog kompleksa tektonski reducirane sink li ­ nalnc slruklure. u svakom sl llcaju, ii zoni spajanja snopa helikoidalnih rasjeda suslava, gdje se lim rasjedima zalvaraju rigidniji rragmcnli, i gdje jc oeita promjcna pruzanja vanjskih rasjc­ da sllslava, kao i sve to ved nagib jedinstvenc rasjedne plohc, ll s lij ed dcsnog krclanja krila dolaz i do rorm iranja c kstenzijskc zone (rams a y & i-luber, 1987), i' ijilll progrcsivnim razvojem naslaje suslav zjapecih pukolina (s1. 6), mecl usobno uglavnom povezanih. to je poscbno izrazeno u kompaktnim vapnenaekim stijcnama kojc su i 1i podini klasticnih nisnih naslaga, ukoliko su ove prisutnc u strukturi i na povrsini. takve ce pukotine na povrsini bili rijetko vidlj ive; usli­ jed g ravilacijskog povijanja iii obrusavanja dijelom sll za tvorcnc i skrivcne. znacenje opisani h helikoidalnih rasjedni h sustava je visestruko. moze se primijeniti u rijcsavanjll slruklll rnog sklopa i njegovc genczc u podrucjima ka rak lcrizi ranim tangencijalnim boranim i rasjednim strukturama isto­ znacne vcrgencije. geologia croa!ica 50/1 nadalje, ukoliko sc primjeni obrnuti postupak od trcli ­ ranog u ovom radu, jasno je istaknuta mogucnost paleo­ geografske i palinspaslicke rckonstrukcije primarnih odnosa, kao i pracenje promjcna tijekom geodinamskog procesa. valja poscbno istaknuti i znacenjc hclikoidalnih ras­ jednih sustava u hidrogeologiji. na s li c i 6 dijclom su naznaccnc i hidrogeoloske lllogc slijena i strukturni h e le­ mcnata. slijedi i kratki komentar takovog prikaza. rasjeclni kontakt vapnenaekog i klasl ienog komp leksa je i kontakt propusnih i nepropusnih naslaga; klasticne nasi age u ovakovim odnosima prcdslavljaju visecli bari­ jeru relativno dubokog elosega. obicno su to tektonski llkljdteni rlisni sed imenti uz rasjede sllslava. s takovom ulogom jasno dijelom odrcduju i krelanje podzemne vode ll horizontalnom i vertikalnom smislu. no, i sami heli­ koielalni rasjedi sustava, unutar okrsenog vapnenackog kompleksa, igrajll znacajnll hidrogeolosku ulogu; cluz ras­ jeda rasjednih zona mogu se pretpostaviti privilegirani slllje rovi toka podzcmnc vode; okom ito na njih pret­ postavlja se zna(no slllanjena mogllcnost protjecanja. u zonama formiranih zjapccih pukot ina unutar rasjednog suslava, duz kojih je logieno ocekivali i spcleoloske objc­ kle, s velikom vjerojalnoscll mogu se j"ormirati izvori i znacajnijeg kapacilela. 3. zakljucak rczultati rada mogu se svcsti u ncko li ko zakljllcaka. sustavi helikoidalnih rasjeda predstav ljaju konve rge­ ntni snop rasjeda koji se spajaj u ii jedinstveni rasjed reverznog karaklera . znacajni su za te rcilc oznacene kompresijskim tangencijalnim sl ruktu rama. nastaju kao rezu llal deformacija esaloni ranog rasporcda bora, u pravilll izgradenih iz kompetciltnih i nekompetenlnih stijena, izlozenog hor izonta lnom strcsll . recentni slruklurni sklop nastaje relativnom promjenom smjcra horizonlalnog stre­ sa, slo dovodi do horizontalnog kretanja liz pojedinc ras ­ jedc sustava. u toj drugoj fazi geodinam skog proeesa mogllce je formiranj c ekstenzijsk ih zjapecih pukotina ii kompaktnim sl ijcnama u rasjednim zonama. s obzirom na posebno izrazenu hid rogeoloskll ulogu u krskim tercnima, rasjcdi helikoidalnog sustava, unu tar pro­ pllsn ih stijena i 1i dodiru s nepropllsnima, mogu biti privi ­ legirani pravc i lokova podzemne vode, odnosllo zone izdasnih izvora, posebno na mjestima ekstenzijskc dezintc­ grac ije stijena. primjena op isanog 1110dcla bila bi pozeljna ll terenima sa sl icnim geo loskim odnosima, a to znaci u sirokom poja­ sll vanjskih dinarida, iako ni kronostratigrarski ni pro­ storno nije ogranicena i na druge arealc. manuscript received september 9, 1996. revised manuscript accepted april 28, 1997. 1. introduction previously, biomechanical analyses have been widely applied in anthropology and primatology and sporadically in the study of caviomorph rodents. recently, because of the rich fossil record and contemporaneous presence of similarly designed, yet differently adapted forms, k u n s t (1996) applied biomechanical analyses on femora of pleistocene european bears. along with other skeletal traits, femoral cross-sectional shape was interpreted in ursus spelaeus as being indicative of limb bone structure designed primarily for static stability. therefore, the previous study of the cave bear limb bones from croatian sites based on the variability of bone lengths, width of epiphysis and diaphysis (k r kl e c , 1997; j a m b r e π i ê et al., 2000) is now extended to the analysis of the inner structure, because the internal bone structure yields some information on bone loading which can be analyzed and interpreted in bioosteometry, variability, biomechanics and locomotion pattern of the cave bear limb bones from croatian localities gordana jambre©i∆ and maja paunovi∆ mechanical terms. thus, the aim of this paper is to test a hypothesis of convergent adaptation that was registered on the metapodial bones from mixnitz (s i v e r s , 1931). 2. material and methods the sample of 1328 limb bones of adult cave bears comprises 147 humeri, 392 radii, 218 ulnae, 160 femora, 343 tibiae, and 58 fibulae originating from different middle and late pleistocene levels (oxygen isotope stages 6-2) of the vindija, velika peêina, and veternica (nw pannonian croatia) and cerovaëke peêine caves (e central croatia) (table 1). the results are analysed together for each site because of the low statistical frequency of bones in stratigraphically different levels (table 1). different lengths and widths were measured after d r i e s c h (1976) and t s o u k a l a & g r a n d a l d ’ a n g l a d e (1997) with a digital calliper. the data obtained were compared and also used for computation of the robusticity index (ir), representing the ratio of the mean value of the smallest diaphysis diameter and maximal bone length, and bone index (bi) representing the geologia croatica 55/1 1 10 8 figs. 5 tabs. zagreb 2002 key words: cave bear, limb bones, rtg-osteometry, variability, biomechanics, locomotion, pleistocene, vindija, velika peêina, veternica, cerovaëke peêine, croatia. institute of quternary paleontology and geology, croatian academy of sciences and arts, a. kovaëiêa 5, hr-10000 zagreb, croatia; e-mail: goga@hazu.hr abstract the estimated styloand zeugopodial bone index is lower for the cave bears from the mountainous region (cerovaëke peêine caves) than the bone index from the hilly-lowlands caves (vindija, velika peêina, veternica) and indicates that limb loading depends on the body mass and palaeoenvironment. the type of movement was similar to the locomotion of the recent brown bear but with somewhat more expressed plantigrady on the hind limbs. at the same time, the sex ratio of the studied material depends firstly on the site morphology (endogene or exogene cave), i.e. its function (dense or periodically visited shelter), and also on geological processes and human activity. kljuëne rijeëi: spiljski medvjed, kosti udova, rtgosteometrija, varijabilnost, biomehanika, lokomotorika, pleistocen, vindija, velika peêina, veternica, cerovaëke peêine, hrvatska. saæetak analize dugih kosti udova (stilopodija i zeugopodija) spiljskih medvjeda iz pleistocenskih naslaga spilja hrvatske pokazale su niæe vrijednosti indeksa kostiju za medvjede koji su obitavali u visokogorskom podruëju (cerovaëke peêine) u usporedbi s medvjedima breæuljkastog tipa nalaziπta (vindija, velika peêina, veternica). takvi rezultati dovode do zakljuëka da naëin optereêenja udova ovisi kako o masi tijela tako i o okoliπu. naëin kretanja spiljskih medvjeda sliëan je naëinu kretanja recentnih medvjeda s neπto jaëe izraæenom plantigradnoπêu straænjih ekstremiteta. istodobno omjer spolova na obraenim lokalitetima prvenstveno ovisi o morfologiji terena i samog nalaziπta (egzogena ili endogena spilja), njegovoj funkciji (brlog ili povremeno skloniπte) te o geoloπkim procesima i ljudskoj aktivnosti. 2 geologia croatica 55/1 ratio of the mean value of the smallest diaphysis diameter and diaphyseal length. diaphyseal length is the maximal length of a central axis which is defined as passing through two reference points. these reference points are different for each bone: femur (fig. 1): proximal point lies on the superior face, in the middle between the femoral head and the greater trochanter, while the distal one is the most projecting point of the central trochlea; humerus: proximal point is located on the caput humeri and the distal one on the condylus humerii between the trochlea humerii and capitulum humerii; radius: proximal point is situated on the caput radii and distal one on the facies articularis carpea. diaphyseal length of ulna, fibula and tibia c o r r espond to the maximal bone length. for selected bones from each site radiographs were taken with the aim of measuring outer diameter (d), inner diameter (m), lateral cortical thickness (cl), and medial cortical thickness (cm) at 50% of the diaphyseal length from the distal end and perpendicular to the central axis (fig. 1). these parameters have been used for calculation of the general cortical index (ci), medial cortical index (cim), lateral cortical index (cil) and cortical area (ca). ci=((cm+cl)/d)x100, cim=(cm/d)x100, cil=(cl/d)x100, ca=d2-m2 data were analysed with “k-means clustering” and the “hierarchical joing (tree clustering)” method (rohlf, 1992). to test our results, comparisons were made with relevant data obtained from the material of the conturines, herdengel, and gamssulzen (reisinger & hohen e g g e r, 1998), azé and berzé (a r g a n t , 1 9 9 1 ) , cova eiros (grandal d’anglade, 1993) caves and 38 other caves from spain (torres perezhidalgo, 1988). 3. stratigraphy and palaeogeography the present analysis was performed in order to try to confirm the hypothesis that the difference in morphology of the cave bear limb bones, opposite to the variability registered on the teeth, reflects distinct environmental conditions and not different geological age. namely, considering the age, the studied material was found in levels ranging from the ois 7 or 6 to the ois 2. thus, site level humerus radius ulna femur tibia fibula vindija e, f 8 36 17 8 21 g 17 67 26 13 30 h 3 40 15 4 58 i 9 9 5 12 j 4 27 30 7 50 k 27 4 24 l 7 35 11 13 46 m 1 3 1 veternica d-j 29 36 33 27 39 11 cerovaëke c 62 62 63 67 52 13 velika p. d, e, f 10 1 1 g, h, i 6 34 14 2 12 20 j, k 17 8 2 13 table 1 frequency of the limb bones found in pleistocene levels of the vindija, veternica, cerovaëke peêine and velika peêina caves. fig. 1 measuring points for radiograph analyses. for better understanding of the problem, the stratigraphy of the investigated material must be reconsidered. the sample from the vindija cave derives from deposits divided into 13 stratigraphic levels: the levels m and l appear to date to the ois 7 or 6, unit k was previously correlated with the eemian (ois 5e), levels j-d encompass the last glacial (ois 5d-2), while the upper three levels are holocene (p a u n o v i ∆ et al., 2001). the cave bears from the velika peêina cave were found in level k (probably stadial phase of the middle würm), but also in levels j-i (interstadial phase of the middle würm), e-h (late würm), and d (last glacial maximum). in the cerovaëke peêine cave (p a u n o v i ∆ et al., 2001) only one fossiliferous level was registered and dated to the last glacial, i.e. to the ois 3. supported by palaeontological evidence the uppermost pleistocene levels d and e from the veternica cave are ascribed to the ois 2, and the levels f, g and h to the ois 3 (paunovi∆ et al., 2001). also, the radiometrical data (table 2) obtained from croatian sites (wild et al., 2001), as well as from austrian and italian caves (leitner-wild & steffan, 1993) show clearly the different ages of analysed populations. at the same time, considering the geographical characteristics of the investigated sites, the analysed material was found in the caves belonging to: (1) the hilly-lowlands part of nw pannonian croatia (vindija, velika peêina, veternica) and (2) the dinarides mountainous part of e central croatia (cerovaëke peêine). during the last glacial the northwestern part of croatia was quite near to the ice cover of the alps, while the northeastern area was part of huge steppe areas of the pannonian basin which featured a different vegetation, and was characterised by the dominance of sand steppe meadows, grassy steppes, riparian forests, and mixed deciduous and coniferous forests in the hilly regions. at 3jambreπiê & paunoviê: osteometry, variability, biomechanics and locomotion pattern... cave layer age method vindija e 18,500 14c f/d/d 26,000 14c g1 28,020 ams g1 29,080 ams g1 27,010 u/th g1 33,100 u/th g1 33,000 ams g3 41,000 u/th g3 42,000 amino acids g3 >42,000 ams h 90,500 u/th i/j 168,400 u/th j 171,200 u/th k 245,600 u/th velika peêina e 26,450 14c g 31,168 14c i 33,850 14c veternica c 13,660 14c i >43,200 14c cerovaëke c >40,000 14c conturines surface 17,900 u-series gst4 44,500 u-series spelaeothem under the bones >257,000 u-series gamssulzen fossiliferous layer 38,000 14c fossiliferous layer 25,000 14c fossiliferous layer 25,250 u-series fossiliferous layer 27,250 u-series herdengel upper complex 37,000 14c main fossiliferous layer 45,000 u-series main fossiliferous layer 65,800 u-series main fossiliferous layer 66,400 u-series basal complex 126,900 u-series basal complex 135,200 u-series table 2 radiometric dates from the vindija, velika peêina, veternica, cerovaëke peêine, conturines, gamssulzen and herdengel caves (after w i l d et al., 2001, and l e i t n e r wild & steffan, 1993). 4 geologia croatica 55/1 the same time, the dinarides (as the southern extension of the alps) played the role of a physiographic barrier between north and south. although not glaciated today, they have supported isolated glaciers and were characterised by high mountain (?alpine) vegetation developed on a karstic relief. considering their palaeogeographical characteristics, i.e. the climate and altitude, the caves from austria (conturines, gamssulzen, herdengel), france (azé, berzé) and spain also belong to these two main environmental types (fig. 2). 4. results 4.1. sexual dimorphism the first step in recognizing the problem of expressed sexual dimorphism registered among bears (p e r k i n s , 1973; stirling, 1993; reisinger & hohenegger, 1998), required separation of the limb bones samples into those representing males and females. the histograms and dendrograms (fig. 3) showed a clear bimodal distribution for all bones especially in the case of greatest and physiological length in each site. thus, the differences in sex ratio obtained by cluster analysis strengthen the clear differentiation into sexes obtained by univariate analyses. while in the investigated 6 limb bone elements from velika peêina the ratio is 73 : 61, in all other sites it is approximately 71 : 61. 4.2. biometric analyses because of the danger of allometric effects, i.e. size dependence of proportions which is especially relevant in materials representing variability in size and distributions (sex ratio), the frequency distribution for each bone from each site was estimated (fig. 4). it appears that all samples exhibit the same allometry, that the deviations from the regression are a result of modification, and that the single change deduced from the present data is size difference between geographically different populations. the hierarchical joing (tree clustering) method showed the size variability of all limb elements, and a similar disposition for both sexes within the cluster of higher values for vindija, velika peêina and veternica, and the cluster of lower values for cerovaëke peêine, conturines, herdengel and gamssulzen (fig. 5). a robusticity index, ratio of the mean value of smallest diaphysis diameter and maximal bone length, was calculated for both sexes together, by reason of comparison with relevant but unsexed data from some european localities. calculated and compared robusticity index ir (table 3) indicates the highest values for humeri (10.211.7) and tibiae (10.6-12.5). the ir of femora varies from 9.0 to 10.6, of radii from 7.5 to 11.0, of ulnae from 6.7 to 8.9, and of fibulae from 4.6 to 5.3. the strongest bones are the humerus and tibia. at the same time, the ir of femora most probably indicates different types of locomotory and loading pattern: values higher than 10.0 are registered among material from veternica, vindija, velika peêina and are similar to the indices from azé, berzé and the iberian caves. on the other hand values lower than 10.0 are characteristic for bones from cerovaëke peêine, conturines, herdengel and gamssulzen (fig. 6). thus, biometric analyses, including robusticity index as an indicator of body size, show variability of the limb bones and the difference in body mass between geographically distinct populations of the cave bear. 4.3. biomechanical and locomotory analysis the analysis consists of calculation and comparison of the bone index (bi), cortical index (ci) and cortical area (ca). fig. 2 absolute altitude (msl) of the studied caves. 5jambreπiê & paunoviê: osteometry, variability, biomechanics and locomotion pattern... fig. 3 examples of sex separation by k-means clustering method. nllla • vindija 350 3ild 250 200 1150 11)0 50 -<>ciurir no. 1 """"'" -a....-n1i.2 b c d e f gl h fi1iiiii8 vbr1ibils tibia velika pecina 350 300 250 200 150 100 50 --<>cluster no.1 females 0 ._.0-... cluster no.2 a b c d e f g h males variables tibia veternica 350 300 250 200 150 100 50 --<>cluster no.1 females 0 ... -0-... cluster no.2 a b c d e f g h males variables tibia cerovacke pecine 350 300 250 200 150 100 50 --<>cluster no. 1 females 0 .... 0-.cluster no.2 a b c d e f g h males variables 6 geologia croatica 55/1 the bone index (bi) reflects the ratio between the mean value of the smallest diaphysis diameter and diaphyseal length. unlike the maximal length (used in ir), representing linear distance between two punctuate points on the epiphyses, diaphyseal length strictly connote maximal length of a central axis and therefore represent the length of the most laden part of the bone. accordingly bi could indirectly reflect a type of bone loading. the estimated bi for cerovaëke peêine and conturines, herdengel and gamssulzen caves are very similar, while the bi of the bears from the veternica and fig. 4 example of distribution around intermediate regresion. fig. 5 example of size variability based on metric parameters for material from the caves veternica, vindija, cerovaëke peêine, herdengel, conturines and gamssulzen by joing tree clustering method. fig. 6 example for values of robusticity index (ir) calculated for material from the caves veternica, vindija, velika peêina, cerovaëke peêine, herdengel, conturines and gamssulzen, azé, berzé, cova eiros and iberian caves. 7jambreπiê & paunoviê: osteometry, variability, biomechanics and locomotion pattern... velika peêina caves are higher, approximately 5-10% for males and 10-12% for females (table 4, fig. 7). calculated general cortical index (ci), medial cortical index (cim), lateral cortical index (cil) and cortical area (ca), which also reflect the limb loading type, posture and locomotory pattern (table 5), were examined by the hierarchical joing (tree clustering) method. the dendrograms clearly show two main clusters conhumerus radius ulna femur tibia fibula vindija 10.8 8.6 7.6 10.2 11.9 velika peêina 8.0 8.9 10.6 11.6 5.0 veternica 10.4 7.5 7.8 9.9 11.7 4.6 cerovaëke 10.2 6.7 6.7 9.7 11.1 4.8 conturines 10.2 6.8 7.3 9.6 11.1 gamssulzen 10.6 7.0 7.4 9.8 11.1 herdengel 10.3 6.9 7.5 9.8 11.3 iberian caves 11.5 10.9 10.4 11.7 aze . 10.5 10.0 9.9 11.6 4.3 berze . 11.7 9.1 10.5 12.5 cova eiros 10.4 11.0 10.2 10.6 5.3 table 3 robusticity index (ir) calculated for the material from the veternica, vindija, velika peêina, cerovaëke peêine, herdengel, conturines, gamssulzen, azé, berzé, cova eiros and iberian caves. humerus radius ulna femur tibia fibula males vindija 12.0 7.9 7.7 9.2 11.6 velika peêina 8.6 9.8 12.5 5.8 veternica 12.0 8.2 9.2 9.5 12.0 5..5 cerovaëke 11.4 7.2 8.2 9.0 11.6 conturines 11.6 7.9 8.7 9.1 11.4 gamssulzen 11.3 7.9 8.6 8.8 10.9 herdengel 11.4 8.0 8.9 9.0 11.5 females vindija 12.7 8.5 6.9 9.0 11.8 velika peêina 8.6 9.8 12.5 5.8 veternica 12.3 8.0 8.6 9.0 12.1 5.4 cerovaëke 10.8 7.4 7.1 8.7 10.9 conturines 11.3 7.2 8.1 8.7 11.1 gamssulzen 11.6 7.6 7.9 8.7 11.3 herdengel 10.7 7.0 7.2 8.6 11.3 table 4 bone index (bi) calculated for the material from the veternica, vindija, velika peêina, cerovaëke peêine, herdengel, conturines and gamssulzen caves. fig. 7 example for values of bone index (bi) calculated for material from the caves veternica, vin dija, velika peêina, cerovaëke peêine, herdengel, conturines and gamssulzen. 8 geologia croatica 55/1 humerus 7 ca caka ci cil cim % humerus 6 ca ci cil cim % vindija 2816 53.3 28.3 25.0 11.6 vindija 2541 60.0 30.9 29.0 6.1 veternica 2573 50.8 29.8 24.5 17.8 veternica 1525 55.8 30.2 27.9 7.6 2176 60.0 32.0 32.0 0 2400 54.5 29.0 25.4 12.4 cerovaëke 1365 48.8 27.9 20.9 25.1 cerovaëke 1071 45.0 22.5 20.0 11.1 1365 41.8 23.2 18.6 19.8 recent recent 522 41.3 17.2 24.1 28.6 radius 7 ca ci cil cim % radius 6 ca ci cil cim % vindija 1113 56.7 29.7 27.0 9.1 vindija 1008 48.6 27.0 21.6 20.0 1475 59.5 30.9 28.5 7.8 velika peêina 1276 55.0 30.0 25.5 17.0 velika peêina 616 48.2 27.5 20.6 25.0 1200 64.8 35.1 29.7 15.4 veternica 1200 45.0 30.0 20.0 33.4 veternica 800 48.4 27.2 21.2 22.0 1357 56.0 31.7 24.3 23.4 cerovaëke 1008 48.6 27.0 21.6 20.0 cerovaëke 440 37.0 22.2 14.8 33.3 960 58.8 35.2 23.5 33.3 recent 731 42.8 36.6 20.0 45.4 recent ulna 7 ca ci cil cim % ulna 6 ca ci cil cim % vindija 864 63.6 33.3 27.2 9.0 vindija 465 63.6 33.3 30.4 8.7 velika peêina 1525 58.1 30.2 30.3 7.6 velika peêina 1160 47.4 26.7 25.6 4.1 veternica 1088 53.4 37.5 22.5 40.0 veternica 825 42.8 25.7 17.1 33.4 1449 60.4 30.2 23.2 23.2 1365 52.3 23.8 23.8 0 cerovaëke 1056 60.0 31.4 28.5 9.2 cerovaëke 585 55.5 29.6 25.9 12.5 362 54.0 31.8 27.2 14.4 recent recent 528 53.3 25.0 17.8 28.8 femur 7 ca ci cil cim % femur 6 ca ci cil cim % vindija 2059 58.0 28.0 30.0 6.6 vindija 1375 62.5 30.0 32.5 7.6 1525 58.1 27.9 30.2 7.6 velika peêina 2241 49.0 23.6 25.4 7.0 velika peêina 2080 49.0 22.6 26.4 14.3 veternica veternica 1407 47.7 22.7 25.0 9.2 1452 51.1 22.7 27.2 16.5 1408 50.0 23.2 27.9 16.8 cerovaëke 1860 65.2 30.4 34.7 12.3 cerovaëke 1197 56.4 25.6 28.2 11.1 825 44.2 20.0 22.8 12.2 recent recent 473 38.3 18.5 22.2 16.6 tibia 7 ca ci cil cim % tibia 6 ca ci cil cim % vindija 611 43.0 20.0 23.3 14.1 vindija 1225 67.5 32.4 35.1 7.6 1045 54.3 24.3 27.0 10.0 velika peêina 1161 74.2 37.1 40.0 7.2 velika peêina 1121 48.7 23.0 25.6 10.1 945 63.6 30.3 33.3 9.0 veternica veternica 1710 60.0 28.8 31.1 7.3 1081 65.7 31.4 34.2 8.1 741 65.5 31.0 34.4 9.0 cerovaëke 1196 53.8 25.6 28.2 9.2 cerovaëke 633 60.7 28.5 32.1 11.2 800 63.6 21.2 27.2 22.0 recent 319 60.0 25.0 30.0 16.6 recent table 5 general cortical index (ci), medial cortical index (cim), lateral cortical index (cil) and cortical area (ca) estimated for the cave bear long bones from the veternica, vindija, velika peêina, cerovaëke peêine caves and the long bones of the recent brown bear. 9jambreπiê & paunoviê: osteometry, variability, biomechanics and locomotion pattern... sisting of males and females, and within each of them a disctinct sub-cluster of the cerovaëke peêine cave (fig. 8). the analysis of the cim and cil calculated for the cave bear bones and of cim and cil of the recent brown bear sample, shows that there is a difference in the loading pattern of limbs: on the forelimbs loading is stronger laterally, and medially on the hind limbs. but, there is no distinction between various populations of the cave bear as well as between these two species. 5. discussion because the vertebrate body is defined by dimensions, weight, constitution, and proportions, its characteristics are closely related to the configuration, geometry and distribution of the mass, thus with inner mechanical forces deriving from the activity of the organism and/or caused by external forces connected with the environmental conditions (nikoli∆ & hudec, 1988). for example, performed anthropological studies (© e ∆ er o v , 1973) showed differences between the mountain and lowland populations expressed in the different width of the cortical bone and robusticity of the skeletal elements. these differences were explained with the subsistence and activity pattern of investigated human groups in different surroundings. the investigations of the human long bones were performed using, among other characteristics, the fact that the diaphyseal crosssection is non-homogeneous, and that the stress and tension is stronger on the outer contour of the bone than near the medullar cavity. thus, using the actualistic theory, we have applied the same methods to study the biomechanical and locomotory pattern of the fossil sample, especially because the cave bear was previously treated as a plantigrad animal, and the obtained results showed a clearly different pattern of ecologically different populations. therefore, if external mechanical forces depend on the activity of the organism, but in the first place reflect the ecological influences, the present study leads to the following conclusions: the statement that large sized males are numerous at low altitudes, while females seem to be more abundant in higher regions (reisinger & hohenegg e r, 1998) must be reconsidered. our oppinion is that the sex ratio of the cave bears depends in the first place on the site morphology (exogene or endogene cave), i.e. its function (dense or periodically visited shelter), geological processes and human activity. the estimated bone index is lower for the material from the mountainous cerovaëke peêine caves than the bone index for hilly-lowland sites vindija, velika peêina and veternica indicating that limb loading was caused by the smaller body mass, i.e. the type of movement was similar to the locomotion of the recent brown bear. the rtg-osteometry of the studied bones showed the biggest difference in a cortical area (amount of cortical bone that is proportional to the axial rigidity, i.e. closely related to the body weight) indicating that the hilly-lowland forms from vindija, velika peêina and veternica were heavier and bigger and therefore featured clumsier locomotion. comparison of medial and lateral cortical indices of all samples leads to the conclusion that plantigrady (sensu d e n d a l e t c h e , 1986) described by p r a t & thibaut (1976) and c h a g n e a u (1986) is not a characteristic of the cave bears. from the obtained results it is obvious that the cave bear, similarly to the recent brown bears, was a semiplantigrad with somewhat more expressed plantigrady on the hind limbs. thus, because differences in biometry and biomechanical characteristics between geologically older and younger populations were not registered, the obtained results confirmed only the discrepancy between the fig. 8 example of radiograph analysis performed on material from the caves veternica, vindija, velika peêina and cerovaëke peêine by joing tree clustering method. 10 geologia croatica 55/1 hilly-lowlandsand mountain-populations of the cave bear, and coinciding with the study of v i r a n t a (1994) indicated different limb loading and locomotory patterns. the smaller and more intensively movable forms (?cursorial) of the cave bear were adapted to harsher environmental conditions with insufficient food sources. still, a more integrated approach, i.e. careful morphological (not only metrical) analysis (e.g. articular shape, cross-sectional morphology, muscular scars, etc.) of skeletal elements, especially of the distal elements, is required for future studies of the cave bear because the effects of altitude, local morphology, pleistocene climate and fodder quality upon bear size/morphology remain only partially understood and not straightforward. 6. references a r g a n t, a. (1991): carnivores quaternaries de bourgogne.docum. lab. géol. lyon, 15, 301 p. chagneau, j. (1985): contribution à l’étude des os des extremités des pattes d’u r s u s deningeri romeviensis. comparassion avec ursus arctos et ursus spelaeus .bull. soc. anthrop. s. o., 20/2-3, 61 p. d e n d a l e t c h e , c. (1986): l’ours brun.acta biol. montana, 6, 32-54. dr i e s c h, a. (1976): das vermessen von tierknochen aus vor und frühgeschichtlichen siedlungen.inst. paläeoant. domestikationsf. tiermed., univ. münchen, 111 p. grandal d’anglade, a. (1993): el osos de las cavernas en galicia: el yacimiento de cova eiros.o. castro, 285 p. jambre©i∆, g., krklec, n. & paunovi∆, m. (2000): upper pleistocene bears from cerovaëke caves (mt. velebit, croatia).geol. zbornik, 15 (1998), 41-50. krklec, n. (1997): statistiëko morfogenetska istraæivanja metapodnih kostiju vrste ursus spelaeus iz pleistocenskih naslaga πpilja hrvatske.unpublished phd thesis, university of zagreb, 129 p. kunst, g.k. (1996): femoral morphology of some quaternary bears.acta zool. cracov., 39/1, 269-278. leitner-wild, e. & steffan, i. (1993): uranium-series dating of fossil bones from alpine caves.archaeometry, 35/1, 137-146. nikoli∆, v. & hudec, m. (1988): principi i elementi biomehanike.©kolska knjiga, 442 p., zagreb. paunovi∆, m., jambre©i∆, g., brajkovi∆, d., malez, v. & mauch lenardi∆, j. (2001): last glacial settlement of croatia: catalogue of fossil sites dated to the ois 2&3.acta geol., 26/2, 27-20. perkins, d. jr. (1973): a critique on the methods of quantifying faunal remains from archaeological sites.domestikationsforschung und geschichte der haustiere, int. symp. budapest 1971, proceedings, 367-369. prat, f. & thibault, c. (1976): le gisement de nauterie à la romieu (gers).fouilles de 1967 à 1973. ed. mus. nat. hist. nat., 35, 1-82. r e i s i n g e r, c. & h o h e n e g g e r, j. (1998): sexual dimorphism in limb bones of late pleistocene cave bear (ursus spelaeus, carnivora, mammalia) from three caves in eastern alps (austria and italy).boll. soc. paleont. ital., 37/1, 99-116. rohlf, f.j. (1992): ntsys-pc numerical taxonomy and multivariate analysis system.state university of new york and exeter software, new york. sivers, w. (1931): die struktur der handund fusswurzel des höhlenbären von mixnitz.paleobiol., 4, 257-301. s t i r l i n g , i. (1993): the living bears.in: stirling, i. (ed.): bears. harper collins, 240 p. ©e∆erov, d. (1973): rendgen-anatomske osobine kostiju donjih ekstremiteta u vezi s profesijom.folia anat., 2, 87-101. torres perez-hidalgo, t. (1988): osos (mammalia, carnivora, ursidae) del pleistoceno de la peninsula iberica.publicaciones especiales, bol. geol. min. espana, 203-312. tsoukala, e. & grandal d’anglade, a. (1997): system of measurements on ursid skeleton.international meeting “man and bear”, auberives-en-royans, proceedings, 1-19. viranta, s. (1994): limb bone proportions and body mass of the cave bear (ursus spelaeus ).hist. biol., 7, 239250. wild, e.m., paunovi∆, m., rabeder, g., steffan, i. & steiner, p. (2001): age determination of fossil bones from the vindija neanderthal site in croatia.radiocarbon, in print. manuscript received november 21, 2000. revised manuscript accepted may 20, 2002. larva.indd 299 � ab stra ct at the “pašino vrelo” source, groundwater is exploited by means of wells which tap a carbonate aquifer of badenian age. the natural quality of groundwater complies with the provisions of the regulation on health and safety of drinking water. however, anthropogenic impacts in the form of microbiological pollution have been observed. extensive hydrogeological investigations have been conducted in recent years in the recharge area of the groundwater source with the aim of ensuring additional quantities of drinking water and protection of the source from pollution. the analysis of hydrogeological monitoring results for groundwater levels and discharges at the groundwater source confi rmed the existence of a hydraulic connection between the quaternary alluvial and badenian carbonate aquifers. differences in the hydrodynamic conditions between the “pašino vrelo” spring and “bojanića vrelo” spring have also been observed, and are related to the infl uence of pumping on the groundwater discharge regime, but also to drainage conditions at the springs. hydrochemical indicators also suggest the mixing of groundwater from both aquifers in springs and exploitation wells. specifi c hydrogeological conditions at the groundwater source determined the concept of its development. recent hydrogeological research was carried out in order to explore the possibilities of tapping deeper parts of the carbonate aquifer in order to minimise the infl ow of groundwater with anthropogenic impacts from the shallow alluvial aquifer during groundwater abstraction. preliminary results for groundwater quality in the new well justifi ed the aforementioned investigation approach. intensive exploitation of the well will show whether these conditions are sustainable in the long term. keywords: carbonate/alluvial aquifer, groundwater, hydrodynamics, hydrochemistry, isotopes, groundwater quality protection, groundwater pollution hydrodynamic and hydrochemical conditions at the groundwater source “pašino vrelo”, with a focus on its development � ozren larva, tamara marković and vinko mraz department of hydrogeology and engineering geology, croatian geological survey, sachsova 2, 10 000 zagreb, croatia; (olarva@hgi-cgs.hr) doi: 104154/gc.2010.24 geologia croatica 63/3 299–312 12 figs. 1 tab. zagreb 2010 geologia croaticageologia croatica 1. introduction the “pašino vrelo” source of drinking water is located in the sunja river valley, between the settlements of borojevići and mečenčani in the sisak-moslavina county, in the municipality of hrvatska kostajnica (fig. 1). it is named after the “pašino vrelo” spring, which is the most important hydrogeological phenomenon in the region. there is another spring at the groundwater source – “bojanića vrelo”, as well as pumping site facilities comprising four abstraction wells (pvb-1, pvb-2, pvb-3, and spbpv-1/06) and several observation wells. the “davidovića vrelo” and “grabovac” geologia croatica 63/3geologia croatica 300 springs occur in the vicinity of the groundwater source. the former is periodic and the latter a perennial spring. with respect to surface waters, the sunja river is the most prominent watercourse, but there are also a few smaller streams – e.g. the bekej stream in the south-eastern part of the groundwater source. the pumping site has been active since the 1970s, when two wells were drilled, based on favourable results of hydrogeological and geophysical investigation works. today, three active wells abstract groundwater from the carbonate aquifer of badenian age which underlies the quaternary alluvial aquifer. both aquifers form the “pašino vrelo” aquifer system, the hydrodynamic and hydrochemical characteristics of which had not previously been extensively explored. the nominal yield of the pumping site is 38.4 l/s, however, in practice about 20 l/s are abstracted on average, due to the limited fl ow rate in the distribution network. the natural quality of groundwater complies with the provisions of the regulation on health and safety of drinking water (og 47/08). however, specifi c hydrogeological conditions in the aquifer together with the occurrence of polluters in the immediate vicinity result in occasional microbiological pollution of groundwater. such circumstances were important considerations in determining the concept of groundwater source protection, and in the investigative works carried out in recent years in order to ensure additional quantities of drinking water. in recent times there is a renewed need for abstraction of larger quantities of water at the pumping site, since the configure 1: location map showing the studied springs and wells. ceptual design of the water supply system anticipates, in its fi nal stage, a maximum daily water consumption of 108 l/s. the objective of this study was to increase the level of understanding of hydrogeological model of the “pašino vrelo” groundwater source. this was accomplished by conducting analyses of the hydrodynamic and hydrochemical characteristics of both the quaternary alluvial aquifer and badenian carbonate aquifer. research was undertaken between 2005−2007. a groundwater monitoring program was established in order to interpret the hydrodynamics of the aquifer system. it included monitoring of groundwater levels in the alluvial aquifer, water levels in the “pašino vrelo” spring and discharge of both the “pašino vrelo” and “bojanića vrelo” springs. on several occasions, groundwater samples were taken from springs and wells for the purpose of defi ning the hydrochemical conditions in the aquifer. besides the measurements of physical and physico-chemical parameters of groundwater in situ, analyses were subsequently conducted in laboratories regarding the basic chemical composition and the ratios of stable hydrogen and oxygen isotopes in the groundwater. application of the mass-balance model facilitated estimation of the proportions of water from carbonate and alluvial aquifers in the wells and springs under different hydrological conditions. the research results provided the basis for updating the protection zones according to the regulation on the determination of sanitary protection zones of the source (og 55/02) and directed the investigations towards deeper parts larva et al.: hydrodynamic and hydrochemical conditions at the groundwater source “pašino vrelo”, with a focus on its development geologia croatica 301 figure 2: hydrogeological map. 1 – geological boundary; 2 – supposed geological boundary; 3 – supposed transgressive boundary; 4 – fault; 5 – supposed fault; 6 – reverse fault; 7 – plio-pleistocene clastic sediments, pl, q – poorly permeable rocks; 8 – quaternary alluvial sediments, al-q2 – dominantly very permeable rocks; 9 – badenian lithothamnium limestone, m4 – permeable rocks; 10 – eocene, ottnangian, sarmatian and pannonian clastic sediments, e, m3, m5, m6 – dominantly impermeable rocks; 11 – drilled well; 12 – dug well; 13 – exploratory borehole; 14 – intake. of the carbonate aquifer with the aim of abstracting additional groundwater quantities without anthropogenic contamination. thus, in 2005, an exploratory borehole spbpv -1/05, and a year later a test exploitation well spbpv-1/06 were drilled west of the pumping site. the results of the pumping test as well as of chemical analyses of groundwater from the well are promising with respect of both groundwater abstraction quantity and quality. 2. hydrogeological characteristics of the groundwater source in the greater area of the groundwater source, deposits range in age from the palaeogene to the quaternary (fig. 2). the palaeogene is represented by eocene fl ysch sediments (e), which are characterized by both vertical and lateral exchange of sandstones, shales, siltites and conglomerates. weathering of these resulted in materials which formed younger sediments. the possibility of groundwater accumulation in them is slight, but they are therefore characterized by a developed surface hydrographic network. the springs in these deposits have low yields, of 0.1 l/s or less. ottnangian clastites (m3) discordantly overlie the eoce ne deposits. they appear as erosion remnants in eocene fl ysch, and consist predominantly of alternations of clayey sands and clays. badenian deposits (m4) transgressively overlie the ottnangian sediments. the basal part of these mostly consists of loosely cemented conglomerates or breccias, with fragments of older bedrock. they are overlain by carbonate rocks represented by lithothamnium limestone. these rocks are porous, and thus enable infi ltration of surface waters and circulation of groundwater. besides the porosity, the badenian rocks are often also characterized by karst phenomena sinkholes, smaller caves and conduits with signifi cant local infl uence on the hydraulic characteristics of the deposits. sarmatian and pannonian sediments (m5 and m6) are predominantly represented by marls, and plio-pleistocene clastites (pl, q) are mostly clays, clayey sands and sometimes gravels. the youngest deposits are quaternary alluvial sediments (al, q2), which are found in the sunja river valley. they are represented by gravels, sands, clays and clayey gravels with boulders of older rocks, and originate from the weathering and resedimentation of older rocks. the deeper parts mostly consist of coarser, prolluvial deposit, with subsequent sedimentation of river sediment. the sunja river frequently changed its course in the past, which caused vertical and lateral geologia croatica 63/3geologia croatica 302 interfi ngering of coarse-grained gravel, sand and sandy and gravelly clay. the whole sunja alluvium is approximately 10 m thick, unconsolidated to poorly consolidated sediment, which in its coarse-grained parts, enables infi ltration and circulation of groundwater. from the hydrogeological standpoint, these sediments can be categorized as either impermeable or permeable rocks. eocene, ottnangian, sarmatian and pannonian clastites are impermeable rocks, whereas the group of permeable rocks includes the carbonate deposits of badenian age and plio-pleistocene and quaternary alluvial sediments. in the lithological cross-section in the greater area of the “pašino vrelo“groundwater source, the quaternary alluvial aquifer is located immediately above the badenian carbonate aquifer. the appearance of the springs was enabled by favourable structural-tectonic relationships. these are characterized by the dinaric strike of the main structural units and tectonic elements. along the faults, there appears to be a gradual lowering of neogene deposits towards the northeast. repeated tectonic movements caused fracturing of hard carbonate rocks, thus creating conditions for infi ltration and circulation of water below ground. the appearance of the “pašino vrelo” and “bojanića vrelo” springs are consequences of a pronounced diagonal fault in the sunja valley, which brought into direct contact permeable lithothamnium limestones and impermeable pannonian marls. impermeable marls caused the appearance of upward springs in this part of the sunja river valley, thus forming the “pašino vrelo” groundwater source. 3. hydrodynamic conditions at the groundwater source the fi rst known data on yields at the “pašino vrelo” groundwater source date back to 1970-1974 (magdalenić et al., 1976). the characteristic values of daily discharges at the “pašino vrelo” spring at that time were: qmax = 115 l/s; qmin = 52 l/s; qmean = 75 l/s. the authors state that the minimum discharge of the “pašino vrelo” spring group, which also includes the “bojanića vrelo” spring, exceeds 80 l/s. at the end of 2005, hydrogeological monitoring was again established in the greater area of the pumping site. groundwater levels were monitored in dug wells, piezometers and an exploratory borehole (fig. 3). the dug wells tap the quaternary alluvial deposits of the sunja river, whereas the piezometers, exploratory well and drilled wells tap the badenian carbonate aquifer. water levels were monitored at the “pašino vrelo” spring, while spring yields were estimated at “pašino vrelo” spring and “bojanića vrelo” spring using weirs. upstream and downstream of the pumping site, staff gauges were installed in the sunja river. figure 3: equipotential map with groundwater fl ow direction and outer boundary of the ii. protection zone. 1 – geological boundary; 2 – supposed transgressive boundary; 3 – fault; 4 – supposed fault; 5 – plio-pleistocene clastic sediments, pl. q – poorly permeable rocks; 6 – quaternary alluvial sediments, al-q2 – dominantly very permeable rocks; 7 – badenian lithothamnium limestone, m4 – permeable rocks; 8 – eocene, ottnangian, sarmatian and pannonian clastic sediments, e, m3, m5, m6 – impermeable rocks; 9 – drilled well; 10 – dug well; 11 – exploratory borehole; 12 – perennial spring; 13 periodic spring; 14 – intake; 15 – staff gauge; 16 – equipotential line; 17 – groundwater fl ow direction; 18 – piezometric head; 19 – outer boundary of the ii. protection zone larva et al.: hydrodynamic and hydrochemical conditions at the groundwater source “pašino vrelo”, with a focus on its development geologia croatica 303 fi gu re 4 : groundwater levels in dug wells and the “pašino vrelo” spring with linear regression lines. fi gu re 5: depths to groundwater in dug wells and springs disc charge. interpolation of groundwater levels in the monitored facilities and the water levels between the staff gauges in the sunja river allowed construction of a groundwater equipotential map for low water levels conditions on 17 november 2006 (fig. 3). groundwater fl ow has a general south-east direction. the drainage infl uence of the river is observed as well as a cone of depression caused by groundwater abstraction at the pumping site. hydrodynamic conditions in the badenian carbonate and quaternary alluvial aquifers were investigated by analysing a groundwater level time series at the pumping site and in its recharge area as well as through the yields of the “pašino vrelo” and “bojanića vrelo” springs. oscillations of groundwater levels in the quaternary alluvial aquifer and the water levels in the spring “pašino vrelo”, revealed opposite trends (fig. 4). in the quaternary alluvial aquifer, groundwater levels show a trend of lowering from the beginning of june to mid-november 2006. conversely, the “pašino vrelo” spring showed a trend of rising water levels over a slightly longer monitoring period from the beginning of march to mid-november 2006. the yields of the “pašino vrelo” and “bojanića vrelo” springs show different dynamics from november 2005 to december 2007 (fig. 5). the values registered at the “pašino vrelo” spring range from 6.7 l/s in january 2006 to 25 l/s in february and april 2007. on the other hand, the “bojanića vrelo” spring shows greater oscillations in yield, ranging from 3.5 l/s in august 2007 to 50 l/s in december 2007. when the yields of the “pašino vrelo” groundwater source between 2005−2008 are compared to the yields of the same spring between 1970−1974, a substantial decrease is quite obvious. geologia croatica 63/3geologia croatica 304 in order to assess the hydrological conditions in the region and their possible infl uence on the reduction in spring yields, the following data were analyzed: • a time series of stage data on the sunja river from 1965−2009. the gauging station is located in sunja (fig. 1). the stage data were analyzed separately for the periods 1965-1987 and 1987−2009 because the gauging station was moved from its original position to a new location at the beginning of 1987. • a time series of precipitation data for 1965−2009 at the main meteorological station at sisak (fig. 1), located approximately 20 km to the north of the investigated area. analysis of the stage data on the sunja river shows no meaningful trend (figs. 6a, b). however, the precipitation data shows a defi nite increasing trend (fig. 7). total annual precipitation ranges from 590 to 1160 mm. the lowest and the highest amounts of precipitation were registered in 1971 and 2002 respectively. in the 44-year period, mean annual precipitation was 893 mm. these hydrological conditions could not lead to the observed reduction of spring yield. based on performed analyses, it could be concluded that the lowered yields in recent years are mostly a consequence of groundwater exploitation over a long time. in addition to the observed differences in the ratios of maximum to minimum yields in the “pašino vrelo” and “bojanića vrelo” springs, occasional variation in trends were also apparent (fig. 5). thus, for instance, in the period from 26 april to 28 june 2006, the yield of the “pašino vrelo” spring increased from 11.5 l/s to 22.3 l/s. at the same time, the yield of the “bojanića vrelo” spring decreased from 38 figure 6: sunja river stages at the gauging station in sunja with a linear regression line for a) 1965−1987 and for b) 1987−2009. a) b) larva et al.: hydrodynamic and hydrochemical conditions at the groundwater source “pašino vrelo”, with a focus on its development geologia croatica 305 l/s to 22.3 l/s. these circumstances are partly related to the impact of pumping on the discharge regime at the “pašino vrelo” spring, but above all to the different hydrodynamic characteristics of the two springs. corresponding yield trends of the “bojanića vrelo” spring and hydrographs of groundwater in wells k-3 and k-9 are also signifi cant. in the periods marked by a decrease in groundwater levels in the wells, the yield of the “bojanića vrelo” spring also decreased, and vice versa – an increase in the yield of the “bojanića vrelo” spring is followed by increased water levels in the wells. conversely, yields of the “pašino vrelo” spring do not show such correlation with water levels in the quaternary alluvial aquifer. in november 2006, a pumping test was conducted on the spb-pv-1/06 well. during the continuous pumping rate of 21.9 l/s, it was noticed that discharge from the “pašino vrelo” spring remained relatively unaltered at 20 l/s whereas discharge from the “bojanića vrelo” spring was only 4 l/s. although the spring yields were not controlled immediately prior to the start of pumping test, measurement data 13 days prior to pumping may serve for orientation purposes when discharge from the “pašino vrelo” spring was 24 l/s, and 22 l/s from “bojanića vrelo” . about ten hours after the pumping test was completed, the yield of the “pašino vrelo” spring remained at 20 l/s, whereas the yield of the spring “bojanića vrelo” increased from 4 l/s to 10.7 l/s. analysis of the hydrodynamic characteristics of the badenian carbonate and the quaternary alluvial aquifers in the greater area of the groundwater source, indicate a hydraulic connection between the genetically distinct aquifers and different groundwater discharge conditions at the “pašino vrelo” and “bojanića vrelo” springs. the “pašino vrelo” spring shows greater yield stability and is more strongly infl uenced by infl ow from the carbonate aquifer when compared to the spring “bojanića vrelo”. conversely, the “bojanića vrelo” spring is more directly influenced by the hy dro dynamic conditions in the alluvial aquifer, as confi rmed by a very good positive correlation of yields of the “bojanića vrelo” spring and groundwater levels in the quaternary alluvial aquifer. 4. hydrochemical characteristics of groundwater during june and september 2006 as well as april, september and october 2007, groundwater samples were taken from the wells (pvb-1, pvb-2 and pvb-3) and from the springs (the “pašino vrelo” and “bojanića vrelo”) at the ground water source “pašino vrelo”, as well as from the “grabovac” spring, which drains the groundwater from the lithothamnium limestones. water samples were also taken from the sunja river. prior to sampling, the following parameters were measured ‘’in situ’’ by probes of the wtw company: electrolytic conductivity (ec), total dissolved solids (tds), temperature (t), ph and oxygen content in waters to be sampled. at the hydrochemical laboratory of the department of hydrogeology and engineering geology at the croatian geological survey, the concentrations of basic anions: chlorides, sulphates and nitrates were measured by ion chromatograph (by the laballiance co.), whereas the concentrations of orthophosphates and ammonium were measured by spectrophotometer dl/2010 (by the hach co.). concentrations of the basic cations: calcium, manganese, sodium and potassium were measured by atomic adsorber (perkin elmer co.). the content of hco3 was determined by titration. ratios of the stable isotopes of hydrogen (δd, δ2h) and oxygen (δ18o) in sampled water were measured at the joanneum research forschungsgesellschaft mbh, institute of water resources management (wrm) hydrogeology and geophysics in graz, austria. water temperatures ranged from 10.7 to 21.2oc (table 1), the smallest variations being observed in springs and wells (11 to 12oc). this indicates the mean annual temperature in their recharge area. however, water temperatures in fi gu re 7: total annual precipitation at the sisak meteorological sta tion with linear regression line for 1965−2009. geologia croatica 63/3geologia croatica 306 the surface fl ow of the sunja indicate differences in temperatures during colder and warmer mon ths as a consequence of cooling and warming of the watercourse. it has long been observed that temperatures in surface water bodies show diurnal and annual oscillations, rela ted to weather conditions, particularly atmospheric tem perature (keery et al., 2007). the ph-values range from 7.02 to 8.26, thus the waters are neutral to mildly alkaline (table 1). the water from the springs is well saturated with oxygen, whereas the water from the wells is poorly saturated with oxygen (table 1). poorer oxygen saturation of well waters is a consequence of the consumption of oxygen in the alluvial aquifer for different chemical reactions, such as the oxidation of organic matter, mineral wear, nitrogen transformation processes, etc. the measured ec values range from 222 to 581 µs/cm (table 1). higher ec values and total dissolved solids (tds) were measured in the water of the “grabovac” and “bojanića vrelo” springs as well as well pvb-3. slightly lower values were measured in the other wells (pvb-1 and pvb-2) and in the “pašino vrelo” spring and the lowest values were measured in the sunja watercourse itself (table 1). the ec and tds values of the measured waters indicate a grouping of springs and wells according to the proportion of waters from lithothamnium limestones and alluvium, depending on hydrological conditions. during wet months (maximum and medium waters), a signifi cant infl uence of waters from the alluvial aquifer was observed in the wells pvb-1 and pvb-2 and in the springs “bojanića vrelo” and “pašino vrelo”, whereas in the drier period (minimum waters) there is a stronger infl uence from the lithothamnium limestones. in the pvb-3 well, water from the lithothamnium limestones was the dominant infl uence observed throughout the hydrological year. according to the basic ionic composition (piper diagram), the analyzed groundwater belongs to the ca-hco3 water type, while the water sampled from the sunja river belongs to the camg-hco3 water type (fig. 8). such hydrochemical facies of water is a consequence of the dissolution of carbonate minerals in the recharge area of the springs, wells and the river. the quantity of dissolved carbonate minerals depends on the partial pressure of co2, i.e. the solubility of co2 in water, since its solubility increases simultaneously with the increase of partial pressure of carbon dioxide leading to increased quantities of carbonic acid and greater solubility of carbonate minerals (stumm & morgan, 1996; hem, 1989). if, however, for some reason, the partial pressure of co2 is reduced, there is a reduction in its solubility, and the opposite reaction becomes possible – precipitation of carbonate minerals (garrels & christ, 1965; macpherson et al., 2008). the saturation index of water is a measure which serves as an indicator of changes in balance between the solid phase (carbonate minerals) and liquid phase (groundwater). fi gu re 9: distribution of calculated saturation indices of calcite and dolomite and logpco2 of sampled waters. fi gu re 8: piper diagram of sampled waters from the study area. larva et al.: hydrodynamic and hydrochemical conditions at the groundwater source “pašino vrelo”, with a focus on its development geologia croatica 307 based on the results obtained by chemical analyses, partial pressure of co2, indices of saturation of calcite and dolomite are calculated by application of the geochemical massbalance model netpath (plummer et al., 1994). it is evident that the sampled waters are mostly saturated with respect to calcite, and unsaturated in respect of dolomite (fig. 9). a higher (positive) partial pressure of co2 is observed during the colder months compared to warmer months (fig. 9). a higher partial pressure of co2 during colder months is a consequence of the transport of organic matter from the surface of the terrain into the underground, under conditions of low soil and air temperatures, so that co2 is not released from the soil, but dissolves in the water. in addition, there is higher precipitation (snow and rain) in the colder months, dissolving co2 and infi ltrating it below ground. conversely, in the warmer months, with less precipitation and higher air and soil temperature, co2 is released from the soil, thus creating a lower partial pressure of co2 in groundwater. due to a higher partial pressure of co2 carbonate rocks dissolve, thus the values of calcite saturation index are lower, or in some cases, water is unsaturated with regard to calcite (e.g. “grabovac”/09/07). lithothamnium limestones are more soluble than carbonate boulders which comprise the quaternary alluvial aquifer, thus the ec values of water from the lithothamnium aquifer are higher in relation to waters from the alluvial aquifer. similarly, understanding changes in the balance between the solid phases (carbonate minerals, i.e. cal cites and dolomites) and the liquid phase (groundwater) is important for the natural control of groundwater quality. heavy metals which show an affi nity for the carbonate minfi gu re 10: plot of calculated mixing portions of waters from ‘’bo janića vrelo’’ and ‘’pašino vrelo’’. fi gu re 11: stable isotopic composition of water samples collected from the spring and wells at the ‘’pašino vrelo’’ groundwater source relative to the meteoric water line from klagenfurt. geologia croatica 63/3geologia croatica 308 eral phase tend to be deposited together with calcite, mostly in the form of coatings, and leach out from water (herrera et al., 2008; curkov et al., 2008; lakshtanov & stipp, 2007; zachara et al., 1988, 1991). estimation of the proportions of water from the lithothamnium and alluvial aquifers in the “pašino vrelo” and “boja nića vrelo” springs, and wells pvb-1, pvb-2 and pvb-3 was carried out using the netpath software (plummer et al., 1994). this program was used to interpret net geochemical mass-balance reactions between the initial waters that mix and the fi nal waters along real fl ow paths in aquifers or other hydrologic systems. the program uses geochemical modelling techniques (plummer et al., 1983; plum mer, 1985; parkhurst & plummer, 1993; glynn & brown, 1996; nordstrom, 2007) to construct geochemical reaction models, using chemical and isotopic data for waters from the hydrochemical system. the model is a set of mixing fractions and mole transfers that precisely account for the changes in concentration of elements in the waters (plummer et al., 1994). models between selected evolutionary waters are found for every possible combination of the plausible phases that can account for the composition of a selected set of chemical and isotopic constraints in the system (plummer et al., 1994). simultaneous water drainage was observed at springs from both aquifers (fig 10). however, the proportions change depending on hydrological conditions. thus, in the conditions of lower and medium waters (september 2006, april 2007 and september 2007), the prevailing groundwater component is from the carbonate aquifer. conversely, during high waters, groundwater from the alluvial aquifer prevails (june 2006 and october 2007). from the measured ratios of stable oxygen and hydrogen isotopes, it is evident that the waters from the “pašino vrelo”, “bojanića vrelo” and “grabovac” springs, and the wells pvb-1, pvb-2 and pvb-3, are directly infl uenced by renewal from recent precipitation, since the values are evenly dispersed along the local meteoric water line (lmwl) – klagenfurt (fig. 11). changes in the δ18o ratio of monitored waters are small, indicating a complex hydrogeological system in the recharge zone of the springs and wells of the “pašino vrelo” groundwater source. the recharge area of the sunja river is on mt. “zrinska gora” (fig. 1), where altitudes range from about 178 m a.s.l to about 600 m a.s.l. depending on the hydrological conditions (precipitation quantity and season), the measured δ18o values were more negative (-9.96 o/oo) when the sunja is infl uenced by tributaries from the higher altitudes and colder precipitation, while they were more positive (-9.36 o/oo) in reverse conditions (fig. 12). the sunja recharges the alluvial aquifer in its valley, and thus infl uences the isotopic composition of water in wells and springs (fig. 12). however, at times of low waters, the isotopic composition of spring waters is infl uenced by groundwater from the lithothamnium limestones. a similar scenario was observed between the waters from the “grabovac” and “bojanića vrelo” springs. at times of high waters, both springs have the same recharge area, i.e. the hilly parts of mt. “zrinska gora”. however, the δ18o values measured at times of low waters indicate the recharge of these springs from higher altitudes. furthermore, the measured negative δ18o values in water samples from the “pašino vrelo” spring indicated that its recharge area is larger, encompassing not only the hilly parts of the mt. “zrinska gora” area but also mt. “zrinska gora” itself. at higher altitudes, where the average temperatures are lower, precipitation is isotopically depleted (clark & fritz, 1997). this altitude effect is useful in hydrogeological studies, as it distinguishes groundwater refi gu re 12: stable isotopic composition of waters sampled from grabovac, sunja, ”bojanića vrelo’’ and ‘’pašino vrelo’’. larva et al.: hydrodynamic and hydrochemical conditions at the groundwater source “pašino vrelo”, with a focus on its development geologia croatica 309 table 1: results of measured physical, physico-chemical and chemical parameters of the sampled waters. ec (µs/cm) tds (mg/l) t (°c) ph o2 (%) ca2+ (mg/l) mg2+ (mg/l) na+ (mg/l) k+ (mg/l) hco3 – (mg/l) so4 2– (mg/l) cl– (mg/l) no3 – (mg/l) nh4 + (mg/l) po43-p(mg/l)  pvb-1-06-06 367 256 11.4 7.47 55 63.9 4.2 4.1 1.7 203 11.5 1.9 4.9 <0.01 0.03 pvb-1-09-06 361 252 12.5 7.56 60 82 4.2 9.9 3.3 274 11.3 3.2 4.3 <0.01 0.04 pvb-1-04-07 340 238 10.8 7.74 50 69 4.8 12.4 2.1 240 12.7 3.5 4.4 <0.01 0.05 pvb-1-09-07 375 263 12.2 7.48 48 70 5.4 13.2 2.3 248 14.4 4.6 4.8 0.01 0.02 pvb-1-10-07 366 256 12.9 7.59 57 64.2 4.7 13.2 1.9 246 14.4 4.3 4.3 <0.01 0.04 pvb-2-06-06 366 256 11.3 7.47 47 66.1 5.7 6.7 1.7 203 11.8 1.7 4.5 0.07 0.05 pvb-2-09-06 360 252 12.5 7.56 59 85 5.7 9.8 3.3 274 11 2.8 3.9 0.01 0.04 pvb-2-04-07 338 237 11.7 7.5 70 69.5 4.7 12.5 2.1 240 12.7 3.5 4.3 <0.01 0.03 pvb-2-09-07 379 265 12.4 7.53 54 70 5.3 13.1 2.3 248 14.6 4.7 5.0 0.02 0.06 pvb-2-10-07 367 257 12.7 7.5 50 63.8 4.7 13.3 2.1 245 15.9 3.2 4.5 0.01 0.05 pvb-3-06-06 409 286 11.5 7.34 52 77.4 6.1 5.9 1.4 254 9.6 2.9 4.8 0.03 0.05 pvb-3-09-06 407 285 11.8 7.5 60 92 6.1 8.9 2.7 303 9.4 6.8 4.3 <0.01 0.05 pvb-3-04-07 397 277 11.7 7.28 50 64.8 5.6 14.4 1.6 238 9.7 6.2 4.3 <0.01 0.05 pvb-3-09-07 419 293 12.2 7.55 43 74.3 5.8 14.4 2.2 252 10.6 4.7 4.7 0.02 0.06 pvb-3-10-07 400 291 12 7.52 52 61.1 5.3 14.6 1.8 238 11.8 5.6 4.5 0.02 0.05 “pašino vrelo”-06-06 357 250 11 7.2 72 67.9 5.4 4.4 1.7 214 12 2.3 4.5 <0.01 0.04 “pašino vrelo”-09-06 355 249 11.8 7.42 57 90 5.4 10 3.3 277 10.7 4.3 3.8 <0.01 0.04 “pašino vrelo”-04-07 330 231 11.3 7.47 60 67.2 4.8 12.8 2.1 240 12.5 5.6 4.2 <0.01 0.04 “pašino vrelo”-09-07 375 263 11.8 7.43 50 60.3 4.8 13.4 2.3 240 15.6 2.7 5.3 0.02 0.04 “pašino vrelo”-10-07 365 256 11.9 7.49 43 61.2 4.2 13.7 2.2 238 17.3 3.4 4.7 <0.01 0.04 “bojanića vrelo”-06-06 381 266 13.3 7.39 53 68 5.5 7.5 1.7 240 9.6 4.2 5.1 0.08 0.03 “bojanića vrelo”-09-06 397 278 12 7.42 78 95 5.5 11.1 2.7 283 8.1 8.4 4.1 <0.01 0.05 “bojanića vrelo”-04-07 375 262 11.3 7.52 66 69.3 4.5 15.8 1.9 242 9.1 9.7 4.9 <0.01 0.05 “bojanića vrelo”-09-07 402 281 11.4 7.48 55 64.7 5 14.9 2 245 9.5 4.8 4.9 0.01 0.02 “bojanića vrelo”-10-07 406 284 10.7 7.57 80 60 4.8 15.9 1.9 238 10.1 6.6 4.9 0.02 0.07 “grabovac”-06-06 581 406 11.3 7.42 84 124 1.1 1.6 0.7 391 5.3 1.3 3.1 0.03 0.01 “grabovac”-09-06 570 399 11.2 7.32 96 124 0.8 2.6 0.8 396 4.9 2.4 3.3 <0.01 <0.01 “grabovac”-04-07 552 386 13.2 7.62 95 75.8 1.2 6.2 0.5 250 4.5 1.5 2.7 <0.01 0.04 “grabovac”-09-07 446 372 12 7.23 80 86.4 0.7 5 0.6 262 4.1 1.2 2.6 <0.01 0.01 “grabovac”-10-07 550 385 11.3 7.33 78 93.8 1.7 6.5 0.5 278 4.6 1.3 2.9 <0.01 0.07 the sunja river-06-06 291 203 21.2 7.8 103 49 8 4.6 1.5 178 13.4 1.8 3.4 <0.01 0.01 the sunja river-09-06 311 218 15.7 8.26 121 74 8 10 2.9 178 11 4.3 3 <0.01 0.01 the sunja river-04-07 246 172 15.4 7.9 116 49.4 7.8 12.9 1.7 170 14.3 4.3 2.8 <0.01 0.02 the sunja river-09-07 222 155 13.3 7.86 100 31.7 3.3 12.9 2.1 100 16.2 4.9 8.8 0.03 0.02 the sunja river-10-07 307 215 12.6 7.69 129 44.8 4.3 14.3 1.9 160 17.9 4.0 3.0 0.02 0.04 geologia croatica 63/3geologia croatica 310 charged at high altitudes from that recharged at low altitude (clark & fritz, 1997; rozanski et al., 1993). concentrations of ammonium and orthophosphates in water samples are below the mpc values (table 1). however, increased concentrations of ammonium and orthophosphates during washing out of upper parts of alluvial deposits were observed in the wells. increased concentrations of ammonium and orthophosphates indicate the infl uence of domestic wastewater (doyle & parsons, 2002; celen et al., 2007). a sewerage system in the settlements surrounding the groundwater source has not yet been constructed, so the inhabitants discharge their wastewater into canals along the road and, during precipitation, wastewater from the canals is infi ltrated into underground. in the “grabovac” spring, increased concentrations of ammonium and orthophosphates are occasionally registered. however, their origin is natural, i.e. caused by the decomposition of organic matter (leaves, twigs, etc.) on the forest fl oor. concentrations of nitrates in all water samples are well below the mpc values (table 1). agricultural activity is not intensive in the area (mostly meadows and pastures, less fi elds), thus there is no possibility of groundwater pollution by manure or mineral fertilizers. similarly, concentrations of sulphates and chlorides are also well below the mpc values (table 1). the origin of sulphates and chlorides in groundwater is natural, since the aquifers are composed of rocks which contain chloride and sulphate or sulphide bearing minerals. it can be generally stated that the waters of the “pašino vrelo” groundwater source are of good quality in terms of chemical indicators. however, microbiological indicators suggest groundwater pollution with domestic wastewater, as confi rmed by occasionally raised concentrations of ammonium and orthophosphates. 5. development of the groundwater source in 2005, an exploratory borehole (spbpv-1/05) was drilled north-west of the pumping site, followed a year later by a test exploitation well spbpv-1/06, with the aim of ensuring the availability of additional quantities of groundwater (fig. 3). the well was 152 m deep, and the aquifer was tapped in the 50−105 m and 120−137 m intervals. during the pumping test with a quantity of 21.9 l/s, a drawdown of 3.95 m was achieved. an exploitation capacity of at least double this is expected, which could not be confi rmed during the pumping test, since a pump of adequate capacity was not available. groundwater samples were taken during testing for chemical analyses in order to determine the proportions of groundwater from different parts of the aquifer system. 83 % of groundwater was from the lithothamnium limestone with only 17% from the alluvial aquifer, which is signifi cantly more favourable in relation to the other facilities at the pumping site. the results proved that tapping deeper parts of the carbonate aquifer was justifi ed. the sustainability of these conditions will be verifi ed in the course of longterm exploitation of the well. to date, protection of the groundwater source has been carried out through active and passive measures according to the currently unenforced regulation from 1986 (og 22/86). the expert maps for update, which also includes the new well spbpv-1/06, according to the current regulation in force on the determination of sanitary protection zones of the drinking water source (og 55/02), is given by mraz et al. (2007)1. the specifi c characteristics of the hydrogeological system as previously described, were taken into consideration when defi ning protection zones. they played an important role in the defi nition of the ii. protection zone, along the external boundary of which, according to the regulation, groundwater has a minimal travel time of 50 days before it enters groundwater capture. when determining this protection zone, the hydrogeological characteristics of the carbonate aquifer, (which has a primary signifi cance from the water supply standpoint), were not taken into account. the focus was placed on the quaternary alluvial aquifer, since it was assumed that the values of hydraulic conductivity, and thus also of velocity of groundwater fl ow in the alluvial aquifer were higher in relation to the carbonate aquifer. namely, the interpretation of the pumping test results showed that the hydraulic conductivity of the lithothamnium limestone is 3.6 m/day. based on lithological composition of the quaternary alluvial aquifer, data from reference sources and analogy with other areas, a hydraulic conductivity of 150 m/day was estimated. according to the hydrogeological model, pollution from the surface of the terrain leaches vertically to the saturated zone of the alluvial aquifer and then, under the infl uence of the gradient, advances by means of advection towards the well fi eld. bearing in mind the aforementioned conditions, the gradient achieved during the pumping site operation and an estimated value of alluvial aquifer effective porosity of 0.2, the average fl ow velocity in horizontal fl ow was defi ned as 7.5 m/day. in the course of this, the radial fl ow of groundwater in the vicinity of the wells was neglected. given the fl ow velocity and the minimum permissible groundwater travel time in an area included in the ii. protection zone, it was possible to defi ne its external boundary (fig. 3). it was especially convenient for the part of alluvial aquifer located up-gradient from the pumping site, 1 mraz, v., marković, t. & larva, o. (2007): izvorište “pašino vrelo”. zaštitne zone za novi zdenac spbpv-01/06 i vodocrpilište “pašino vrelo” [groundwater source “pašino vrelo”. protection zones for new well spbpv-01/06 and groundwater source “pašino vrelo” – in croatian].– unpubl. report, croatian geological survey, zagreb, 44 p. larva et al.: hydrodynamic and hydrochemical conditions at the groundwater source “pašino vrelo”, with a focus on its development geologia croatica 311 where there is no natural boundary to groundwater fl ow. the external boundary of the ii. protection zone was subsequently adjusted in order to correspond to the boundaries of cadastral plots. in the north it follows the sunja river and the bekej watercourse in the east and south-east. in the west and south-west it follows the natural boundary of the alluvial aquifer and in the north-west, up-gradient from the pumping site, it is located approximately 450 m from the pumping site which is in accordance with the minimum permissible groundwater travel time. 6. conclusion the groundwater accumulated in the carbonate aquifer of badenian age presents an exceptionally valuable natural resource in the municipality of hrvatska kostajnica. the focus of the recent investigations of the “pašino vrelo” aquifer system was placed on the defi nition of its hydrodynamic and hydrochemical characteristics. the results have increased the level of understanding of the hydrogeological model, which in turn enabled better insights into the possibilities of abstraction of additional drinking water quantities of more favourable quality, and adequate protection of the groundwater source from pollution. the analysis of oscillation of groundwater levels and spring discharges at the groundwater source enabled conclusions to be drawn about the hydrodynamic conditions in the aquifer system. a positive correlation between oscillations of groundwater levels in the quaternary alluvial aquifer and the discharge quantities in the “bojanića vrelo” spring proved the hydraulic connection between the carbonate and alluvial aquifers. this had already been indicated by the bacteriological contamination of groundwater abstracted at the pumping site. at the same time, the difference in trends of groundwater levels in the alluvial aquifer and water levels in the “pašino vrelo” spring, as well as in trends of yields in the “pašino vrelo” and “bojanića vrelo” springs pointed to different discharge conditions at the groundwater source. the same conclusion is indicated by the stable discharge of the “pašino vrelo” spring, which did not alter even during the pumping test of the spbpv-1/06 well while, in contrast, the discharge of the “bojanića vrelo” spring was substantially reduced. such hydrodynamic indicators are, to a point, a consequence of the infl uence of exploitation wells (pvb-1, pvb-2 and pvb-3) in operation at the pumping site, but, above all, of a more pronounced groundwater drainage from the carbonate aquifer to the “pašino vrelo” spring, whereas the “bojanića vrelo” spring is more strongly infl uenced by the quaternary alluvial aquifer. calculation of the proportions of water from the lithothamnium and alluvial aquifers in the “pašino vrelo” and “bojanića vrelo” springs, as well as in the pvb-1, pvb-2, pvb-3 and spbpv-1/06 wells, indicates larger proportion of water from the lithothamnium aquifer during low and medium water fl ow at monitored springs and wells, while during high waters there is a larger proportion of water from the alluvial aquifer. groundwater quality in the recharge area of the ‘’pašino vrelo’’ groundwater source is good with regards to its chemical indicators. however, microbiological indicators indicate groundwater pollution with domestic wastewater during high waters as confi rmed by occasionally increased concentrations of ammonium and orthophosphates, which are chemical indicators of the impact of domestic wastewater. the mass-balance model confi rmed the hydraulic connection of the genetically different aquifers. results of the investigations suggested exploration of the possibility of extracting drinking water of adequate quality from the deeper horizons of the badenian carbonate aquifer. initial results are promising. besides the fact that the expected exploitation capacity of the well exceeds water abstraction quantities at the pumping site to date, a favourable ratio of the proportions of water from the carbonate and alluvial aquifers was also determined. if such a ratio remains under conditions of long-term exploitation, a more favourable quality of groundwater in relation to the other wells at the pumping site is guaranteed. while defi ning the protection zones for the groundwater source, the specifi c characteristics of the hydrogeological model were taken into consideration, particularly during definition of the ii. zone of sanitary protection. due to the hydraulic connection between the alluvial and carbonate aquifers, the focus was placed on hydraulic characteristics of the alluvial aquifer when determining the size of the zone. by remedying the anthropogenic infl uences on groundwater quality in the alluvial aquifer, the existing water quality problems at the pumping site will be resolved. acknowledgement the authors wish to express their gratitude to croatian waters for the fi nancial support of the research and state meteorological and hydrological service for providing hydrologic data. the authors also wish to thank anonymous reviewers for their very useful comments. this paper represents part of a hydrogeological investigation within the project entitled the “basic hydrogeological map of the republic of croatia” (project no. 181-1811096-3165) which is fi nanced by the ministry of science, education and sports. references celen, i., buchanan, j.r., burns, r.t., robinson, r.b. & raman, d.r. (2007): using a chemical equilibrium model to predict amendments required to precipitate phosphorus as struvite in liquid swine manure.− water res., 41, 1689–1696. clark, i. & fritz, p. (1997): environmental isotopes in hydrogeology.− lewis publ. crc press, 238 p. curkov, n., cmuk, p., mlakar, m. & omanović, d. (2008): spatial distribution of trace metals in the krka river, croatia. an example of the self-purifi cation.− chemosphere, 72, 1559−1566. doyle, j.d. & parsons, s.a. (2002): struvite formation, control and recovery.− water res., 36, 3925–3940. garrels, r.m. & christ, c.l. (1965): solutions, minerals and equlibria.− harper & row, new york. glynn, p.d. & brown, j.g. (1996): reactive transport model ing of acidic metal-contaminated ground water at a site with sparse spatial information.− in: reactive transport in porous media general principles and application to geochemical processes, reviews in mingeologia croatica 63/3geologia croatica 312 eralogy.− in: steefel, c.i., lichtner, p. & oelkers, e. (eds.): mineralogical society of america, 34 /9, 377–438. hem, j.d. (1989): study and interpretation of the chemical characteristics of natural waters.− u.s.g.s water-supply paper 2254, 263 p. herrera, m.l., espinosa, r.j., milan, j.j. & hiscock, k.m. (2008): integrated hydrochemical assessment of the quaternary alluvial aquifer of the guadalquivir river, southern spain.− applied geochemistry, 23, 2040−2054. kerry, j., binely, a., crook, n. & smith, j.w.n. (2007): temporal and spatial variability of groundwater – surface water fl uxes: development and application of an analytical method using temperature time series.− j. hydrology, 336, 1−16. lakshtanov, l.z. & stipp, s.l.s. (2007): experimental study of nickel(ii) interaction with calcite: adsorption and coprecipitation.− geochimica et cosmochimica acta, 71, 3686−3697. macpherson, g.l., roberts, j.a., blair, j.m., townsend, m.a., fowle, d.a. & beisner, k.r. (2008): increasing shallow groundwater co2 and limestone weathering, konza prairie, usa.− geochimica et cosmochimica acta, 72, 5581−5599. magdalenić, a., jurak, v., kovačević, s. & capar, a. (1976): diffi culties with groundwater tapping in sunja valley. 4th yugoslavian symposia on hydrogeology and engineering geology – book 1, skopje, 223−234. nordstrom, d.k., (2007): modeling low-temperature geochemi cal processes.− in: drever, j.i. (ed.): treatise on geochemistry, volume 5−surface and ground water, weathering and soils: elsevier, 1–38. og 22/86: regulation on protection measures and conditions for determination of sanitary protection zones of the drinking water source. narodne novine (1986): pravilnik o zaštitnim mjerama i uvjetima za određivanje zona sanitarne zaštite izvorišta za piće. no 22, 6 p. og 47/08: regulation on health safety of drinking water. narodne novine (2008): pravilnik o zdravstvenoj ispravnosti vode za piće. no 47, 16 p. og 55/02: regulation on the determination of sanitary protection zones of the drinking water source. narodne novine (2002): pravilnik o utvrđivanju zona sanitarne zaštite izvorišta. no 55, 9 p. parkhurst, d.l. & plummer, l.n. (1993): geochemical models.− in: alley, w.m. (ed.): regional ground-water quality: van nostrand reinhold, chap. 9, 199–225. plummer, l.n. (1985): geochemical modelling − a comparison of forward and inverse methods.− in: hitchon, b. & wal lick, e.i. (eds.): canadian/american conference on hydroge ology, 1st, banff, albe rta, june 1984, proceedings: national water well assocociation, 149–177. plummer, l.n., parkhurst, d.l. & thorstenson, d.c. (1983): development of reaction models for groundwater systems.− geochimica et cosmochimica acta, 47, 665–686. plummer, l.n., preston, e.c. & parhurst, d.l. (1994): an interactive code (netpath) for modelling net geochemical reactions along fl ow path. version 2.0 usgs water-resources investigation report, 94−4169, reston, virginia. rozanski, k., aragaus-aragaus, l. & gonfiantini, r. (1993): isotopic patterns in modern global precipitation.− continental isotope indicators of climate, amer. geo. union monograph. celen, i., buchanan, j.r., burns, r.t., robinson, r.b. & raman, d.r. (2007): using a chemical equilibrium model to predict amendments required to precipitate phosphorus as struvite in liquid swine manure.− water res., 41, 1689–1696. stumm, w. & morgan, j.j. (1996): aquatic chemistry. chemical equlibria and rates in natural waters.− john wiley & sons, inc. new york-chichester-brisbane-toronto-singapore, 1022 p. zachara, j.m., cowan, c.e. & resch, c.t. (1991): sorption of divalent metals on calcite. geochim. cosmochim. acta, 55, 1549– 1562. zachara, j.m., kittrick, j.a. & harsh, j.b. (1988): the mechanism of zn2+ adsorption on calcite.− geochim. cosmochim. acta, 52, 2281–2291. manuscript received september 02, 2009 revised manuscript accepted june 25, 2010 available online november 11, 2010 1. introduction in general, tectonic stylolites are not parallel to bedding and are formed as a result of the spatial tectonic compression of carbonate rocks. they characterize deformed carbonates of orogenic regions. under the influence of tectonic compression, stylolites can be shaped along the present fractured discontinuities or as independently formed systems of stylolite sutures (railsback & andrews, 1995). either case, it is clear that the stylolite columns are oriented parallel to the main stress direction (σ1). if the stylolite columns are not perpendicular to the stylolite suture plane, it means that stylolites have been shaped along the discontinuity plane that already existed (dean et al., 1988). in jurassic limestone foothills of the pyrenees petit & mattaur (1995) have determined two phases of tectonic stylolite occurrences. the first generation of stythe relationship between tectonic stylolites and fold morphology in limestones of the “croatica deposits” (croatia) domagoj jami»i∆ lolites appears in the plane perpendicular to the main stress (σ1) whereas the second generation is connected to extension of left transcurrent fault. this paper describes the tectonic deformational sequence which led to formational processes of tectonic stylolites in pannonian clayey limestones (“croatica deposits”). the genetic link between faults and fracture creation and the process of stylolitization under the influence of local stress with the same orientation has been noticed. stylolites often occur in limestones and marls, either a) parallel to, or b) at an angle relative to the bedding plane. the first stylolite type, parallel to beds has been formed as a result of gravity and sediment compaction. the initial thickness of sediments can be reduced by gravitational processes up to 20-30% (ti©ljar, 1978). in this case, stylolitic sutures are generally parallel to bedding planes and columns are initially oriented perpendicular to bedding. stylolites oriented at an angle relative to bedding, have been created under the influence of oriented stress during tectonic processes. in the case of tectonic stylolites the columns are oriented parallel to stress direction. 2. discussion and results tectonic interpretation of stylolite occurrences in the exploration well core of hampovica-6 (fig. 1) is based on analysis of the relationship between stylolites and present fracture systems. in the 10 cm diameter well core, clayey limestones of the “croatica deposits” show a set of normal faults along which the bedded limestones have been separated in a step-like manner. noted occurrences of stylolites cut by their strike limestone beds together with the faults. 2.1. the genesis of fracture systems the thick fracture system of small dimensions normal faults (fig.1), where single faults are 3-5 mm apart, has a “domino-like” structure. it has been created during folding under the influence of reverse shift between two parallel reverse faults (fig. 2), like a typical riedel sliding system of fractures (r’) which occurred at an angle of 75° to the sliding plane. geologia croatica 55/1 79 81 4 figs. zagreb 2002 key words: stylolites, tectonics, compression, limestone, croatica deposits, lower pannonian, croatia. institute of geology, sachsova 2, hr-10000 zagreb, croatia e-mail: djamicic@igi.hr abstract stylolites associated with axial plane fractures occur in lower pannonian clayey limestones (the “croatica deposits”) from the “hampovica 6” deep exploration well. a genetic link has been observed between the origin of fractures and the process of stylolitization. strong tectonic deformations are present which have been formed under the influence of reverse bed faulting. deformation is pronounced in the shape of folded marl layers along with the creation of thick cleavage (0.3-0.5 cm). along the fractures of axial plane cleavage, microlithons are separated and moved apart for similar values (25 mm) forming a moderate synform. stylolites are formed in the last phase of structure shaping when the effects of the local compressional stress have weakened under the influence of which the breaking off and folding of marl layers occurred. their strike cut the bedding and older fracture systems. 80 geologia croatica 55/1 the successive development of the structure (fig. 2a), show that the set of thick sliding fractures has been formed between two reverse faults in the limestones of hampovica-6 well at the distance of approximately 5 mm. if stress and sliding activities along the reverse faults (fig. 2, b-d) continues further, the fracture planes (r’) progressively internally rotate around the horizontal axis. in the final structural act, the fracture planes are rotated from the initial angle of 75° to the sliding plane of reverse fault for another 65°. during the rotation the fracture has been folded and has obtained a sigmoid shape, while the cut-off limestone beds along the cleavage have drifted apart by various low values. in fig. 3, 3-5 mm wide lithons are observed that have been moved apart along the thick fractures r’. the envelope of such separated microlithons delineate a gentle synform. along the contact with the fracture the beds have been concavely folded as a conseqence of sliding and migration of separated lithons of limestone beds into the apical parts of the synform. at the fracture planes (r’) the records of linear elements that occurre (a-lineation) in the shape of striae have been formed due to sliding along the fractures. taking into account that the well hampovica-6 is vertically positioned, as well as the fact that a-lineation lies in the plane parallel to the well axes, it can be concluded that the main basic stress (σ1), during deformation processes, occurred approximately horizontally. the middle stress axis (σ2) is also horizontal and perpendicular to the well axis, while σ3 is placed approximately along its axis. 2.2. the genesis of stylolites stylolites observed in the hampovica-6 well, have been shaped in a stress field which acted homogeneously over a lengthy period of time without reactivating older, pre-existing fracture systems. along strike, they cut off all planes of different discontinuities, bedding, and fractures (r’) from the axial plane. this shows that stylolites have been created after the final tectonic configuration of the structures present in the well. namely, two sets of different deformations indicate two events of the same compression that is localized only in the part of limestone of this well. the fact is that in the other e x a m i n e d rock samples from this well, coming from more shallow and deeper parts than this interval, neither the stylolitization nor the significant structural deformations have been observed. envelopes of stylolite planes (figs. 1 and 4) mainly follow the well axis and in relation to the present synform are placed into its axial plane. the axis of stylolite columns are horizontally oriented which implies that the strongest main stress (σ1) that led to its formation, acted nearly horizontally, namely, perpendicular to the fig. 1 the core sample of deep exploration well hampovica-6; detail a) shows a fracture system of normal faults, whereas the detail b) shows the stylolites, cleavages and beds relation. fig. 2 the succession of sigmoid fractures formation and spreading of limestone beds between two reverse faults. well axis. as stylolites by their strike follow none of the previously shaped discontinuity planes, it can be concluded that the stress affected previously tectonically shaped and solidified rock. figure 4 shows some stylolite thickness enhancement relative to other parts of the hampovica-6 well sample. (fig. 1). the reduction of limestone beds has been observed along the stylolite suture during the compression and gradual dissolution. the dissolved parts of microlithon beds from left and right side of suture do not have the same dimensions, which is visible in the lower and central part of the fig. 1. as a result of dissolution along some stylolite suture, the clayey limestones were compressed for 2-5 mm. the amplitudes of stylolite sutures are up to 1 mm, whereas the sutures are filled with clayey material that has remained as insoluble rock residue. 3. conclusion two phases of tectonic deformation, directly following one after another can be distinguished on the basis of analysis of fracture systems morphology and the described occurrences of stylolites in the deep exploration well hampovica-6. the deformations described were created as a result of stress, the main axis (σ1) of which acts continuously horizontally, but with different final effects of tectonic deformations. (1) in the first phase fracture systems were created which are the outcome of reverse movements. reverse faults are shaped under the influence of stress σ1 on nearly horizontal line. the shifts along the reverse faults brought to sigmoid folding of accompanying fractures and spacing off of limestone beds for nearly the same values, forming a synform and “domino” structure. (2) in the second phase of the same stress activity, tectonic stylolites appear without occurrences of tectonic transport together with present discontinuity planes. the strike of the envelopes of stylolitic sutures is placed in the axial plane of previously shaped synform. the size of main stress (σ1) in this phase is considerably diminished. the stress acted continuously over a lengthy period of time, facilitating the dissolution of rock content along the stylolite suture. 4. references dean, s.l., kulander, b.r. & skinner, j.m. (1988): structural chronology of the alleghanian orogeny in southeastern west virginia.bull. geol. soc. am., 100, 299-310. petit, j.p. & mattauer, m. (1995): palaeostress superimposition deducated from mesoscale structures in limestone: the matelles exposure, languedoc, france.j. struct. geol., 17/2, 245-256. railsback, l.b. & andrews, l.m. (1995): tectonic stylolites in the “undeformed” cumberland plateau of southern tennessee.j. struct. geol., 17/6, 911-915. ti©ljar, j. (1978): tidal flat, lagoonal and shalow marine carbonate sediments ih the upper jurassic and cretaceous of istria (yugoslavia).acta geologica, 9/5 (prir. istr., 42), 159-194, zagreb. manuscript received march 26, 2001. revised manuscript accepted may 20, 2002. 81jamiëiê: the relationship between tectonic stylolites and fold morphology... fig. 3 detail (a) from fig. 1: 3-5 mm wide lithons (l) have been observed which delineate, by moving apart by the normal faults (r’), the shape of gentle synform. fig. 4 detail (b) from fig. 1: reduction of beds along the stylolite suture (s) with the amplitude of 1-2 mm. 82 geologia croatica 55/1 sokac.indd 1. introduction micropalaeontological analysis of numerous samples collected during field work from various lower cretaceous levels of the karstic dinarides, led to the discovery of new, rich algal associations, particularly from upper barremian–lower aptian deposits. in a sample of algal limestone from mt. biokovo it was possible to determine, at species level, about 15 different taxa, some of which were identified for the first time in that area. however, there were several additional forms which were, at the same time or due to more detailed later analysis, or new descriptions, on some peri-mediterranean lower cretaceous dasyclad species (calcareous algae; dasycladales) previously assigned to different genera branko sokač assigned to the same or different species and different genera. this triggered the re-evaluation of the material stored in our collection and deriving from the same levels at different localities. thus the comparison of numerous existing and newly made thin sections made possible more detailed observations which resulted in some revisions regarding the morphology and/or the taxonomic position of particular species. here, some species ascribed to the genera cylindroporella, macroporella, acroporella, salpingoporella, and korkyrella are included. in total, 250 thin sections were made of the same algal-bearing sample, which almost excluded the possibility of random determinations and enabled assessment of the true variation range of various, sometimes visually different forms. 2. taxonomic descriptions genus cylindroporella johnson, 1954 cylindroporella lyrata masse & luperto-sinni, 1989 pls. i–ii selected synonymy 1989 (part) cylindroporella lyrata n.sp. – masse & luperto-sinni, p 30–39, pl. 1, figs. 1–3, part. figs. 5, 6, non fig. 4; pl. 2, figs. 2, 4, 5, 7, 9, non figs. 1, 3, 6, 8. 1991 non cylindroporella lyrata masse & lupertosinni – schlagintweit, p. 49–50, pl. 19, figs. 6–13, 15–16. non 1993a cylindroporella lyrata masse & luperto-sinni – luperto-sinni & masse, p. 411, pl. 31, fig. 5. 1993b cylindroporella lyrata masse & lupertosinni – luperto-sinni & masse, p. 300–304, pl. 5, fig. 6, non figs. 5, 7. non 1994 cylindroporella ?lyrata masse & luperto-sinni – bodrogi, bona & lobitzer, p. 241–242, pl. 16, figs. 1–5, 8–10. non 1999 cylindroporella cf. lyrata masse & luperto-sinni – bucur, p. 58, pl. 2, figs. 14, 19. geologia croatica 57/1 15–53 3 figs. 3 tabs. 12 pls. zagreb 2004 key words: calcareous algae (dasycladales), taxonomy, biostratigraphy, lower cretaceous, dinarides, croatia. institute of geology, sachsova 2, hr-10000 zagreb, croatia; e-mail: amartek@igi.hr abstract the taxonomic position of some dasyclad species which were previously assigned to the same taxon or, alternatively, were assigned to different genera by different authors, is discussed and revised, respectively. the material described and figured as cylindroporella lyrata masse & luperto-sinni is shown to be heterogeneous (also partly described as salpingoporella robusta sokač) and some figured sections are shown to possess new characteristic features. these forms are therefore singled out and described as biokoviella n.gen. with two species: b. robusta (sokač) n.comb. and b. gusici n.sp. macroporella aptiensis sokač is shown to represent the infertile (sterile) forms of neomeris cretacea steinmann and, consequently, has to be regarded as the younger objective synonym of the latter. new material, with clearly visible morphological characteristics, has enabled the “resurrection” of the controversial genus korkyrella sokač & velić, 1981, and its species, k. texana (johnson), which was originally invalidly described. 16 geologia croatica 57/1 17sokač: on some peri-mediterranean lower cretaceous dasyclad species... remarks in the original description, masse & lupertosinni (1989) mentioned the following diagnostic characteristics: calcified, cylindrical thallus with alternating whorls consisting of alternating sterile and fertile branches. the main species-specific character is the shape of the sterile branches which look like a guitar: swollen in their proximal part, constricted in the middle, and again slightly swollen distally, sometimes acquiring a pyriform shape (masse & luperto-sinni, 1989, figs. 2/1, 2/2; pl. 1, fig. 2; pl. 2, figs. 2, 4–5). on their outer ends, the sterile primary branches bear short secondaries, which, as mentioned by masse & luperto-sinni (1989), appear as crosses in tangential section. each whorl consists of regularly alternating sterile and fertile branches, their total number varying from 8–10. a further distinction is that fertile branches have a slender elongated stalk in their proximal part and a pronounced, bladder-shaped swelling along the outer half of their length. with the above mentioned characteristics, the species has been properly described and its validity is not in doubt. the description is complemented by a graphic reconstruction (masse & luperto-sinni, 1989, fig. 2) and rather numerous sections on two plates. however, among the figured sections two different forms can be visually distinguished: one, with the typical characteristics of the species as described, is figured in the authors’ pl. 1, figs. 1–3, as well as in the lower part (below the line along which the two photomicrographs are pasted together) of fig. 5, and the left and lower section in fig. 6; and in pl. 2, figs. 2, 4, 5, 7, and 9. another form is figured in pl. 1, fig. 4, upper part of fig. 5 and right part of fig. 6, as well as in pl. 2, figs. 1, 3, 6, and 8. as distinct from the first one, the second form does not show alternating sterile and fertile branches; i.e., it does not show the diagnostic characteristics of the species (including the holotype), and consequently, it should be removed from that species. therefore, the allegedly characteristic feature of cross-shaped sections of sterile primaries and their secondaries in c. lyrata, emphasized by masse & luperto-sinni (1989), becomes questionable, the more so because almost the same feature has been quoted as one of the key characteristics in the completed description of the genus acroporella (praturlon & radoičić, 1974, fig. 2d). such, cross-shaped sections are almost impossible to imagine as derived from the tangential plane of a section as figured in masse & luperto-sinni (1989): compare fig. 4 in pl. 1 with figs. 1–3, and the lower part of fig. 5. obviously, we are dealing here with two different forms; the second one, atypical for cylindroporella lyrata and with only one type of branch (= fertile primaries, which bear a tuft of secondaries, with a different distance between the whorls and different density of branches within a whorl) can hardly be conceived as a consequence of a different calcification pattern during growth. to my mind, the original and the later descriptions and illustrations of c. lyrata (luperto-sinni & masse, 1993b, pl. 5, figs. 5–7) included two different forms that occur in the same algal assemblage, which is also the case in the biokovo sample, discussed below. an apparent objection to the above interpretation can possibly be based on the already mentioned section figured in pl. 1, fig. 5 in masse & luperto-sinni (1989), in which, immediately below the joining line of the two photomicrographs, a normal (i.e., continuous) transition from the lower into the upper form seems to be present. however, the apparent junction of the two different forms is situated in a zone where the two forms (i.e., the two specimens belonging to different forms) came to touch each other and where, consequently, dissolution and subsequent recrystallization probably glued the two different specimens together, producing a picture of a seemingly normal transition between different types of pores in the same specimen (thallus). if we do not accept this interpretation, an alternative explanation – much less likely, in my opinion – would be that different parts of the thallus had a basically different morphology. in this case, the older part of the thallus would be characterized by a simpler type of morphology, atypical of cylindroporella lyrata; however, the situation in the section (masse & luperto-sinni, 1989, pl. 1, fig. 5) is just the opposite. several years after the description of c. lyrata, i (sokač, 1993) published a description of a new species, salpingoporella robusta, which was based on a similar – but not wholly identical – material as the one of ‘atypical’ c. lyrata. obviously, i have overlooked those ‘atypical’ sections of c. lyrata which, in spite of some subtle visual differences, can be compared with the sections of s. robusta (sokač, 1993, pl. 1). the general shape of the branches in “s. robusta” (in spite of their visible variability), as well as their alternating position in consecutive whorls and, at that time, lacking the knowledge about the existence of the secondaries, seemed a sufficient reason for including those sections in the genus salpingoporella. however, the newly collected material from the continuation of the same zone which yielded “s. robusta”, contained abundant sections of both typical and ‘atypical’ c. lyrata, as well as numerous sections identical to those described as “s. robusta”. based on this material, the following conclusion emerged: both the ‘atypical’ sections assigned to c. lyrata and those described as s. robusta, which in this material were shown to possess branching ramifications, certainly belong to one and the same taxon, which is characterized by a broad variation in range. based on their identity (= ‘atypical’ c. lyrata and s. robusta), it follows, that both viewpoints, i.e., including the ‘atypical’ sections into the description of c. lyrata and establishing s. robusta as a new species, were erroneous. thus, it follows that both groups of sections (= ‘atypical’ c. lyrata and s. robusta) should be united into a new taxon, that, because of the main distinguishing character of this alga – having one type of bipartite branches, with a characteristic growth 16 geologia croatica 57/1 17sokač: on some peri-mediterranean lower cretaceous dasyclad species... pattern and shape of the secondaries – justifies the establishment of a new genus, biokoviella. based on what has been mentioned above, the valid species cylindroporella lyrata masse & lupertosinni should contain only those specimens that are characterized by the alternation of fertile and sterile branches, as described in the original description (masse & luperto-sinni, 1989, pl. 1, figs. 1–3, 5 (pars), and 6, and pl. 2, figs 2, 4, 5, 7, 9), as well as those figured in the present paper in pl. 1, figs. 1–8, and pl. 2, figs. 1–8. however, the cross-like arrangement of the secondary branches should be deleted from the description because it is highly unlikely that the section in question belongs to c. lyrata masse & lupertosinni. according to the above, the diagnosis of cylindroporella lyrata masse & luperto-sinni should be more restricted, as follows: cylindrical calcified thallus, with narrow axial cavity. branches arranged in dense and clearly alternating whorls. in individual whorls, sterile and fertile branches also are in clearly alternating arrangement. fertile branches have a narrow, shorter or longer stalk in the proximal part, and a pronounced swelling distally. in contrast, sterile branches are widened proximally, narrower in the middle part, and again slightly widened distally, thus acquiring a guitar-like shape. at their outer ends, sterile branches bear short secondaries. some specimens, with slightly pronounced swellings of the proximal ends and evenly narrowed and somewhat elongated distal ends, may appear similar, in some parts of tangential sections, to cylindroporella? barnesii johnson. so far, the discovery of this species within the karstic dinarides is restricted to only one locality on mt. biokovo. the species occurs within the rich algal assemblage (see the descriptions of the biokoviella species) from the top layers of the upper barremian. genus biokoviella n.gen. type species: biokoviella robusta (sokač) n.gen., nov.comb. origin of the name: after mt. biokovo (central dalmatia), where the taxon has been found. diagnosis of the genus: cylindrical thallus, with a narrow axial cavity. branches are divided into clearly differentiated primaries and secondaries and are arranged in whorls. sometimes, the secondaries show a tendency to further divide into tertiaries. in consecutive whorls, primary branches show an alternating arrangement. generally, they are phloiophorous, but may vary in shape; may be more or less swollen, almost cylindrical to rounded wineskin-shaped or club-shaped; some may only slightly widen distally, appearing similar to the acrophorous type. therefore the pores on the outer surface may be large, polygonal or rhombic, densely packed, or else small, rounded, and set widely apart. short secondaries occur in a dense tuft, rarely showing a cross-like arrangement, or, more rarely, irregular and unequal, arranged in a circle. the genus is cladosporous. biokoviella robusta (sokač) nov.comb. pls. iii–v 1989 part. cylindroporella lyrata n.sp. – masse & luperto-sinni, p. 30–38, pl. 1, fig. 4?, 5 (upper part), 6 (transverse and oblique sections in upper right part); pl. 2, figs. 1, 3, 6, 8. 1993b part. cylindroporella lyrata masse & luperto-sinni – luperto-sinni & masse, p. 295–309, pl. 5, fig. 5. non 1993a cylindroporella lyrata masse & luperto-sinni – luperto-sinni & masse, p. 411, pl. 31, fig. 5. 1993 salpingoporella robusta n.sp. – sokač, p. 175– 180, pl. 1, figs. 1–6. 1994 cylindroporella? lyrata masse & lupertosinni – bodrogi, bona & lobitzer, p. 241–242, pl. 16, figs. 1–5, 8–10. 1999 cylindroporella cf. lyrata masse & lupertosinni – bucur, p. 58, pl. 2, figs. 14, 19. the newly observed characteristics of this form, which had previously been assigned to cylindroporella lyrata and afterwards described as a new species of salpingoporella, imply that a revised more complete description, and a revised taxonomic position, are necessary. amended diagnosis: comparatively large, generally phloiophorous, branches may be variously shaped: more or less strongly swollen, with a short stalk, or more club-shaped, widening gradually from the base toward the distal end. the number of branches in a whorl can also vary (table 1). depending on the shape of the primary branches, the consecutive whorls may be seemingly more or less densely spaced. primary branches bear short secondaries, crowded together in a tuft, which are visible as funnel-shaped depressions on the outer surface of the skeleton. some specimens may have irregular secondaries, some of which may even show a tertiary division. as previously mentioned in the original description (sokač, 1993), the cylindrical calcareous skeleton is characterized by a comparatively narrow, sharply delineated, axial cavity which occupies 25–30% of the total diameter. the outer surface shows either funnel-shaped pores (pl. i, figs. 1, 3, 8; pl. iv, fig. 10), through which tufts of secondary branches protrude, or the single pores of dispersed secondaries. the outer surface is frequently abraded, which may give the impression that no secondary branches are developed, and the primaries reach the outer surface (pl. iii, fig. 5; pl. iv, figs. 8–10). bipartite to tripartite branches are arranged into regular whorls with the alternating arrangement of 18 geologia croatica 57/1 19sokač: on some peri-mediterranean lower cretaceous dasyclad species... branches in neighbouring (adjacent) whorls. primary branches have a short, thin stalk (pl. iv, figs. 6, 9–10) or, more rarely, a broad base sticking to the axial cavity. in the latter case, communication with the central cavity is accomplished through a narrow pore, situated in the middle of the broad base (pl. iv, fig. 3). the branches are generally phloiophorous but may vary widely in shape, being distally more or less swollen and acquiring a wineskin-like, robustly bulbous, cylindrical (pl. iv, figs. 2, 7; pl. iv, figs. 5, 6), slightly club-like, or, more rarely, fusiform shape (pl. v, figs. 4, 6). due to the varying diameter, their number in a whorl also varies widely (6–12, most frequently 8–9; pl. iv, figs. 4–7, 9, 10; pl. v, figs. 3–5). primary branches may be situated perpendicularly to the outer surface or may be slightly directed upwards, forming an angle of up to 20º with the horizontal plane (pl. iii, figs. 3, 6–8). the essential distinguishing characteristic of this species are the secondary branches of varying shape, which may grow out either from the distal or lateral surfaces of the primary branches. in general, they are very short and barely visible; most frequently, when compressed (squeezed together) into a tuft, they appear as shallow, funnel-shaped depressions on the outer surface (pl. iii, figs. 7–9; pl. iv, figs. 9–10). more rarely, however, single secondaries growing out from the distal end (pl. iv, figs. 3, 5, 6), or even from lateral surfaces of a primary branch, may be discerned (pl. iv, figs. 4, 6; pl. v, fig. 5). the irregular manner of growth of the secondaries may be visible even on the same primary branch: first growing out in a tuft and gradually individualizing into single secondary branches (pl. iv, fig. 6). in some specimens, individual secondary branches may occasionally be observed growing out irregularly from the lateral surface of a primary branch and showing, distally, a tendency to further, i.e. tripartite, subdivision (pl. iv, fig. 4). in general, the secondaries are also of a phloiophorous shape, slightly widening outwards (pl. iv, figs. 3, 7). their number on a primary branch cannot be established with certainty, but seems to vary from 5–7(?). in those specimens which have fusiform, only slightly swollen (similar to acrophorous), or generally only slightly distally narrowed (shrinking) primary branches, and in which secondary branches grow out in tufts, the secondaries may acquire a crosslike or similar arrangement. this characteristic has been stated by masse & luperto-sinni (1989) to be a typical arrangement of the secondaries growing out of sterile primaries in cylindroporella lyrata, but an almost identical section has been figured by praturlon & radoičić (1974, figs. 2b, d) as an argument for the amended description of acroporella. cysts are seldom observable, but sometimes can be seen in the pores of the large, wineskin-shaped primary branches, which indicates that the species is (was) cladosporous. similarities and differences of the genus biokoviella and its type species: the newly established genus, with the main characteristics as outlined above, appears visually similar to triploporella, particularly to those species that have columnar and somewhat more strongly swollen primary branches, e.g. triploporella? uragieliformis conrad & peybernès, (n.b. according to a remark by a reviewer, m.a. conrad, that species possibly belongs to the genus supiluliumaella, or montenegrella) or else to those in which the primaries are almost acrophorous, as in triploporella bacilliformis sokač. however, the differences between these genera are clearly visible: in triploporella, the axial cavity is, as a rule, much broader, primary branches are of a more regular shape, much more numerous per whorl, and their alternating arrangement in successive whorls is not so clearly expressed as in biokoviella. there is also a difference regarding the secondary branches: in triploporella, the secondaries, though short, are clearly phloiophorous, individual and visibly separated from each other, grouped into distinct tufts, and seldom number more than four. in contrast, in the type species of biokoviella the secondary branches are tightly squeezed together into a tuft, not visibly separated from each other, or else they grow out individually, often most frequently maximum observed length of thallus (l) 8.2 1.20–1.35 outer thallus diameter (d) 0.88–1.50 0.35–1.20 inner thallus diameter (d) 0.24–0.40 0.25–0.35 relation d/d 19–30% 24–28% distance between whorls (h) 0.12–0.24 0.16–0.24 diameter of primary branches (p) 0.15–0.25 0.20–0.24 length of primary branches (l) 0.18–0.48 0.30–0.40 number of primary branches per whorl (w) 6–12 8–9 angle of inclination of primary branches (α) 0–20 diameter of secondary branches (p’) 0.04–0.10 length of secondary branches (l’) 0.10–0.16 0.10–0.12 number of secondaries per primary branch (w”) 4–6 5–6 table 1 main biometric parameters of biokoviella robusta (sokač) n.comb. dimensions in mm. 18 geologia croatica 57/1 19sokač: on some peri-mediterranean lower cretaceous dasyclad species... from lateral surface of the primary branch, and are much more irregular in shape. they are more numerous varying between 4 and 7 depending on the species. with regard to acroporella, differences in the shape of both primary and secondary branches are clearly visible. however, it should be emphasized that another form (i.e., except for the type species) figured in the emended description of acroporella by praturlon & radoičić (1974) and also assigned to acroporella radoicici praturlon, does not belong to that genus, as has been previously mentioned (sokač, 1996). according to the original diagnosis (praturlon, 1964), the genus acroporella includes forms with an unsegmented, cylindrical thallus and long, simple (tubular) acrophorous branches. in contrast, in biokoviella, as mentionend above, the primary branches may have a highly variable shape and bear a tuft of secondaries, some of which may even show a tripartite division. the joint occurrence of biokoviella and suppiluliumaella species, as in the case of the biokovo algal assemblage, makes a comparison between these genera necessary. according to the original diagnosis of suppiluliumaella by elliott (1968), the differences concern the shape of the primary branches and the manner of how the secondaries emerge. in suppiluliumaella, the primaries are long and slender, with a well-developed terminal swelling, out of which swollen and clearly individualized secondaries emerge (see sokač & nikler, 1973). bakalova (1971) also mentions the possibility of third-order branches in s. praebalcanica bakalova; these, however, differ both in shape and the manner of growth from those sporadically developed in the type-species of biokoviella. a similar difference, concerning the shape of both primary and secondary branches and the way the secondaries grow out from the distal ends of the primaries, exists between biokoviella and both montenegrella and crinella, as represented by sokač & nikler (1973). as the type species of biokoviella was originally thought to be a representative of salpingoporella (sokač, 1993), obviously, the two genera may, in some instances, look similar. this similarity arises in cases when the outer surface of biokoviella is eroded (abraded) and thus the traces of secondary branches are lost and primary branches seemingly open on the surface. in the original description of biokoviella robusta, sokač (1993) was misled by such specimens and therefore assigned these to salpingoporella (see plate 1 in sokač, 1993). the “salpingoporella-like” appearance is strengthened by the regularly alternating arrangement of branches in neighbouring whorls. however, the existence of secondary branches, though sometimes only hinted by slight, funnel-shaped depressions, nowadays clearly distinguishes the two genera. stratigraphic position: the species was originally included in the description of cylindroporella lyrata masse & luperto-sinni and also thereafter was frequently cited under that name. its stratigraphic position, both at the type locality and other, later mentioned localities (masse & luperto-sinni, 1989; luperto-sinni & masse, 1993a, b), has been determined as lower aptian. schlagintweit (1991) supposes its possible extension into the upper aptian. sokač (1993), under the name of salpingoporella robusta n.sp., has found this species in a rich algal–foraminiferal assemblage which was dated on the basis of the first appearance of palorbitolina lenticularis (blumenbach) and consequently the age was determined as uppermost barremian–lower aptian. an almost identical stratigraphic position was mentioned by bodrogi et al. (1994), who also determined as transitional, upper barremian–lower aptian levels within the palorbitolina lenticularis zone in the schrattenkalk formation in vorarlberg. bucur (1999) questioned its generic attribution and under the name cylindroporella cf. lyrata masse & lupertosinni recorded its occurrence in the caposeni member of the blid formation on mt. apuseni. the rich algal assemblage of the caposeni member makes a barremian age more likely. the repeated occurrence of the species in sample kj–18 at a new locality on mt. biokovo within an equally rich and diverse algal assemblage (see the description of biokoviella gusici n.sp. in this paper), and immediately below the first finds of palorbitolina lenticularis, also indicates a late barremian age. summing up all data from the localities described so far, it can be concluded that the stratigraphic range of the species can be defined as upper barremian–lower aptian, with possible extension into the upper aptian. biokoviella gusici n.sp. pls. vi–vii selected synonymy 1974 acroporella radoicici praturlon – praturlon & radoičić, p. 17–20, figs. 1b, 2a–d, 3a–d. 1978 acroporella radoicici praturlon, 1964 – bassoullet et al., p. 25, pl. 1, figs. 6–8. ?1989 cylindroporella lyrata n.sp. – masse & luperto-sinni, p. 30–36, pl. 1, fig. 4. ?1993 cylindroporella lyrata masse & lupertosinni – luperto-sinni & masse, pl. 5, fig. 7. 1993b acroporella radoicicae praturlon – luperto-sinni & masse, pl. 4, figs. 11–12. origin of the name: the species is dedicated to my colleague ivan gušić, who established the foraminiferal genus biokovina and thus first introduced the name of mt. biokovo into the palaeontological literature. type locality: mt. biokovo; in a road-cut about halfway between the road branching toward the mountain hut vošac and the peak of sv. jure (1762 m); see fig. 1. coordinates: x = 6423980, y = 4798490. 20 geologia croatica 57/1 21sokač: on some peri-mediterranean lower cretaceous dasyclad species... type stratum: well-bedded limestone, consisting of the vertical and lateral alternation of mudstones, algal and foraminiferal wackestones, and, more sporadically, skeletal–intraclastic grainstones; deposition took place in energetically varied environments in a shallow subtidal zone. the species occurs within a rich algal assemblage of late barremian age, immediately below the first occurrence of palorbitolina lenticularis (blumenbach). holotype: oblique section in pl. 7, fig. 2; thin section kj–18/185. isotypes are represented by variously oriented sections, figured in plates 6 and 7. the original material is stored in the institute of geology, zagreb. diagnosis: cylindrical, unsegmented, calcareous skeleton, with clearly differentiated primary and secondary branches. primaries are arranged in whorls with a clearly alternate arrangement. in general, they are long and slender, slightly, not distinctly phloiophorous, often similar to the acrophorous shape; they bear a tuft of short, equally phloiophorous secondaries, which, if cut at their base, give a cross-like arrangement or are circularly arranged around a larger pore of the primary branch. description: the regular, non-branching, and unsegmented skeleton is built up of yellowish, medium-grained, mosaic calcite. the outer surface is sharply delineated toward the surrounding sediment in specimens with a uniformly abraded outer surface (pl. vi, figs. 5–6; pl. vii, figs. 8–12), or may be shallowly indented in those specimens in which the pores of secondary branches have been partly preserved (pl. vi, figs. 1, 2; pl. vii, figs. 3, 7, 14). specimens with a dark micritic coating are seldom observed (pl. vi, fig. 2). this, being a secondary feature, is of no distinguishing character. the inner, axial cavity is uninterrupted and sharply delineated; it occupies 24–35% of the total diameter (table 2). branches, divided into primaries and secondaries, are situated in distinctly separated whorls and are arranged in clearly alternating position in consecutive whorls. primary branches are long and slender, and because of a slightly developed terminal swelling may be described as indistinctly phloiophorous (pl. vi, figs. 2, 5–6; pl. vii, figs. 1–6). the same characteristic is also clearly visible in the specimens figured by praturlon & radoičić (1974, figs. 2a, c, 3a–c). more frequently, the primary branches are almost acrophorous (pl. vii, figs. 8–9, 12). there are also fusiform branches which are intermediate between the slightly phloiophorous and the almost acrophorous ones (pl. vii, fig. 14). the angle of inclination of the primary branches with regard to the main axis may vary from an almost perpendicular position to an inclination of 45º. each primary branch bears a tuft of secondary branches; in deeper tangential sections, cutting near their emerging points, they appear in a cross-shaped arrangement, which is clearly visible in sections figured by praturlon & radoičić (1974, figs. 2b, d). in cases when the secondaries do not grow out from a common point of emergence but, instead, grow individually and separately from the distal surface of the primary branch, as seems to be the case in some sections in praturlon & radoičić (1974, figs. 2c, 3b) as well as in some sections presented here (pl. vii, figs. 6, 11, 14), they appear in tangential section as a (not fully regular) ring of smaller pores surrounding the large pore of the primary branch (pl. vii, fig. 13). secondary branches are very short, only seldom clearly visible, and also seem to be distally slightly widened (pl. vii, figs. 11, 14). their number in a tuft varies from 4, as indicated by the cross-shaped fig. 1 (a) general position of the locality of sample kj–18 in the territory of croatia. (b) simplified topographic map of the area on the central mt. biokovo, type locality of the sample kj–18. 20 geologia croatica 57/1 21sokač: on some peri-mediterranean lower cretaceous dasyclad species... arrangement, to probably 7 in cases of their individual growth. the species is probably cladosporous. similarities and differences: biokoviella gusici n.sp., as described here, was first thought to represent better preserved specimens of acroporella and was, as such, treated by praturlon & radoičić (1974) in their emended description of acroporella. however, the two species cannot be identical, because biokoviella gusici has secondary branches which are lacking in typical specimens of acroporella radoicici. with the alternating arrangement of branches in neighbouring whorls and sometimes slightly curved and upwardly directed phloiophorous primary branches bearing indistinct secondary branches, it can be confused with salpingoporella verticillata (sokač & nikler). the differences with the latter species, as well as with smaller specimens of salpingoporella pygmaea (pia), to which it can also resemble in some cases, are emphasized by the existence of secondary branches in b. gusici and more densely spaced and more distinctly phloiophorus branches in salpingoporella. with regard to triploporella bacilliformis sokač, which is characterized by stick-like, tubular primary branches bearing short secondaries, the difference between this and the new species is expressed by the number of branches in a whorl, which in t. bacilliformis amounts to 40–50, and by their poorly expressed alternating arrangement, and the larger diameter of the axial cavity. stratigraphic position: biokoviella gusici n.sp. has been found in a sample of upper barremian limestone from mt. biokovo. the sample kj–18 was collected from a sequence of well-bedded limestone, represented by an alternation of poorly fossiliferous mudstone, foraminiferal–algal wackestone, and sporadically vertically and laterally developed skeletal intraclastic grainstone. the latter contain, beside the new species, an abundance of algal remains, among which about 15 taxa, partly known and partly as yet undescribed, could be more or less reliably identified. the following algal species have been determined: biokoviella robusta (sokač), salpingoporella muehlbergii (lorenz), s. verticillata (sokač & nikler), s. patruliusi bucur, salpingoporella sp., cymopolia velici sokač & nikler, “praturlonella” dalmatica sokač & velić, cylindroporella lyrata masse & luperto-sinni, korkyrella texana sokač & velić, triplopoprella? sarda jaffrezo et al., rare specimens of neomeris cretacea steinmann, suppiluliumaelle polyreme elliott, and others. numerous specimens of humiella catenaeformis (radoičić) masse et al. and clypeina? solkani conrad & radoičić, indicating an upper hauterivian age can be found in the deeper underlying layers beneath the sample, while immediately above the algal bearing sample, in a continuous sequence, the first appearance of palorbitolina lenticularis (blumenbach) occurs. therefore, the stratigraphic position of this species at its type locality can be reliably defined as upper barremian. genus neomeris lamouroux, 1816; emend. deloffre, 1970 neomeris cretacea steinmann, 1899 pls. viii–ix selected synonymy 1899 neomeris (herouvalina) cretacea n.sp. – steinmann, p. 149–154, figs. 14–18. 1978 neomeris cretacea steinmann – bassoullet et al., p. 175–178, pl. 20, figs. 7–9. 1989 macroporella aptiensis n.sp. – sokač, p. 1–6, pls. 1–2. 1990 neomeris cretacea steinmann – barattolo, p. 207–218, figs. 5, 6, pls. 1–4. 1993 neomeris cretacea steinmann – granier & deloffre, p. 36, 47. 1993 neomeris cretacea steinmann – soták & míšík, p. 402–403, pl. 12, figs. 1–4, 9. 1993 neomeris cf. cretacea steinmann – soták & míšík, pl. 12, figs. 8, 10. most frequently maximum observed length of thallus (l) 6.5 outer thallus diameter (d) 0.64–1.22 0.70–1.00 inner thallus diameter (d) 0.20–0.44 0.24–0.35 relation d/d 24–43% 24–35% distance between whorls (h) 0.11–0.24 0.11–0.15 diameter of primary branches (p) 0.06–0.12 0.10–0.12 length of primary branches (l) 0.20–0.36 0.24–0.34 number of primary branches per whorl (w) 8–10 9 diameter of secondary branches (p’) 0.04–0.06 length of secondary branches (l’) 0.07–0.14 0.10–0.12 number of secondaries per primary branch (w”) 4–6? table 2 main biometric parameters of biokoviella gusici n.sp. dimensions in mm. 22 geologia croatica 57/1 23sokač: on some peri-mediterranean lower cretaceous dasyclad species... 2002 neomeris sp. aff. n. aptiensis (sokač) nov. comb. – radoičić, pl. v, fig. 4. 2002 neomeris (larvania) conradi n.sp. – radoičić, p. 9–10, pl. i, figs. 1–10, pl. iv, figs. 4, 6–7. 2002 neomeris (larvania) decapoaae n.sp. – radoičić, p. 10, 12, pl. ii, figs. 1–8, pl. iv, fig. 5. remarks in his assessment of this species, barattolo (1990) gave a more complete description of its morphological characteristics and the specific relationship that exists between the primary and secondary branches and the fertile ampoules. he also gave detailed biometric parameters and indicated, in some cases, at their mutual interdependence; he also emphasized that some fertile ampoules are more strongly pronounced than others. however, he doesn’t mention that they appear to be completely absent in the sections of some specimens. it was this lack of distinctly shaped fertile ampoules, in addition to the apparent existence of only one type of indistinctly phloiophorous and irregularly distributed branches (as shown on the outer surface) that misled sokač (1989, pl. 1, figs 1–3; pl. 2, fig. 2) to describe such specimens as a new species of macroporella. also in barattolo’s (1990) paper, some figured sections of n. cretacea (pl. 1, fig. 2; pl. 2, figs. 2, 4, 7) looked very similar to “macroporella aptiensis”. reexamination of the sections figured as “macroporella aptiensis” produced ambiguous results, in that some more distinctly phloiophorous branches that reach the outer surface may in fact represent atypically developed, elongated fertile ampoules. therefore, new samples have been collected at the same locality. analysis of a large number of new thin-sections has proven that most sections of this species belong to forms with slender branches of indistinctly phloiophorous or almost acrophorous type (pl. viii, figs. 1, 2, 4, 8–10; pl. ix, figs. 4, 7), in which the existence of fertile ampoules could not be unequivocally established. however, a few sections (out of many) do show some larger and shorter pores of branches which may indicate their function as fertile ampoules (pl. viii, fig. 3; pl. ix, figs. 5, 8), together with branches typical of the species, such as the sections figured in pl. viii, fig. 5, and pl. ix, fig. 8). later, this species has been found at several more localities at mt. biokovo (pl. ix, figs. 1, 2, 9, 10), as well as in central croatia (locality grabrk). there are some differences, both within individual populations and between them where these are even more pronounced. therefore the question arises, whether sterile individuals were also present in a population, or perhaps some parts of the thallus, in some specimens, were characterized by sterile branches? still another unsolved question concerns the possible existence of sterile third-order branches, as suggested by some branches in sections figured in pl. xiii, fig. 7 and pl. ix, fig. 6 (top part). taken together, all these variations point to the conclusion that rare specimens with indistinct sporangial ampoules as well as those with well-developed ampoules, should be regarded as belonging to the same species. therefore the species macroporella aptiensis sokač, which was later, by radoičić (2002, pl. 5, fig. 4), without further comment, given the designation n. aptiensis (sokač), is here considered to be a younger synonym of neomeris cretacea steinmann and thus should be treated accordingly. species described by radoičić (2002) should also be considered in this analysis, in which i attempted to compare specimens from different localities but from identical or close stratigraphic levels. (n.b. i am grateful to the reviewer, m.a. conrad, for drawing my attention to that paper). the two new species, established by radoičić (2002) – neomeris (larvaria) conradi radoičić and neomeris (larvaria) decapoaae radoičić, are distinguished from one another by minimal differences in some biometric parameters: the d/d relationship and the shape of the more or less elongated gametangia. they have been compared only with tertiary species but not with either the contemporaneous n. cretacea or with the form which was designated by radoičić (2002) as n. aptiensis (sokač) nov.comb. the similarity between the new species described by radoičić (2002) and those specimens with variable characteristics which i included in n. cretacea, are indeed striking. this also applies to their biometric values, which fall within the variation range of n. cretacea. it would appear that all this clearly indicates that the new species established and described by radoičić (2002) should be considered younger synonyms of neomeris cretacea steinmann. the stratigraphic position of the species, with regard to the hitherto known occurrences from the middle albian and cenomanian in the dinarides, can be somewhat lower (older). at two localities in croatia, which are situated rather far apart (mt. biokovo in central dalmatia versus grabrk, southwest of karlovac, central croatia), the species has been found in identical levels that are characterized by the first appearance of palorbitolina lenticularis (blumenbach). it is accompanied by numerous dasyclad algae, e.g., suppiluliumaella polyreme elliott, biokoviella robusta (sokač), korkyrella texana (johnson), salpingoporella dinarica radoičić, etc. the first appearance of n. cretacea in the road-cut between vošac and sv. jure in the more western part of mt. biokovo (in the above mentioned sample kj–18 and in the abundant algal assemblage which also contains typical barremian species), though represented by rare specimens, suggests that the beginning of its development took place as early as the late barremian. a similar stratigraphic range – barremian to albian – is mentioned by soták & míšík (1993) in the lower cretaceous of the west carpathians. 22 geologia croatica 57/1 23sokač: on some peri-mediterranean lower cretaceous dasyclad species... genus korkyrella sokač & velić, 1981 remarks the taxonomic position of the genus korkyrella, which was invalidly described by sokač & velić (1981), has always, since the very beginning been problematic and/or contested. the reasons for this situation can be supposed to be due to the rather intricate structure (morphology), high degree of recrystallization, and generally poor state of preservation. the consequence of this situation has been the variable assignation of this alga to different genera or different species within a particular genus. – the first description of the alga was given by johnson (1965), in an invalid description, under the name salpingoporella texana n.sp. in this publication, only cotypes illustrated in pl. 89, figs. 5–9 in johnson (1965) have been mentioned. – bakalova (1971) assigned fragments of the stalk of this alga to the genus acroporella and described acroporella? nissoviensis n.sp. (bakalova, 1971, pl. 1, figs. 1–3; pl. 2, fig. 7; holotype: slide no. 1260– 1, figured in pl. 1, fig. 1). – jaffrezo et al. (1978) described a new species of the genus pseudoepimastopora, p. pedunculata, based on sections of the upper, swollen, part of the thallus with visible transition into the stalk. this was illustrated by sections in jaffrezo et al. (1978, pl. 2, figs. 1–3, 6, 9; pl. 4, fig. 2; pl. 6, fig. 3; holotype: pl. 2, fig. 2). – peybernès & conrad (1979) labelled similar sections – fragments of the bulbous head with transition into stalk, and possible stalk? (peybernès & conrad, 1979, pl. 2, figs. 4, 5) – as cylindroporella barnesii johnson, whereas an oblique section through the head (pl. 2, fig. 6) was questionably assigned to the same species. – sokač & velić (1981) established the new genus korkyrella. they, however, choose as type-species the invalidly described salpingoporella texana johnson, whereupon this genus also becomes invalidly described. though invalid, the new genus, i.e. its type-species, was illustrated by numerous sections (sokač & velić, 1981, pls. 1–3). – conrad (1982) critically reassessed korkyrella texana and regarded it as being synonymous with cylindroporella barnesii johnson, except for some sections, e.g., those that had been interpreted as stalks (sokač & velić, 1981, pl. 2, figs. 2, 3), which he considered as possibly belonging to other species, e.g., salpingoporella muehlbergii (lorenz). – sokač (1987) analyzed and reinterpreted the genus korkyrella. he supported the validity of the genus, but based it, in retrospect, on an incorrect interpretation of the arrangement and disposition of sterile and fertile branches in the fertile part of the thallus (sokač, 1987, text-fig. 1). in his interpretation (and in the graphic representation), the pores of their secondary branches were considered as the fertile ampoules. the inadequately known structure (morphology) of the alga, that due to various degrees of preservation and different types of sections, may appear as belonging to different taxa, misled him again and he wrongly concluded that the original description contained heterogeneous material and thus pleaded for the complete abandonment of the invalid salpingoporella texana johnson, rejection of the name, and introduction of the irregular new name, “korkyrella ivanovici”, all of which proved, in retrospect, unnecessary and unjustified, because the type-species was invalid and wrongly used, the genus also remained invalid. – masse & luperto-sinni (1989), when comparing their new species cylindroporella lyrata with other species of the genus, dealt also with the renamed korkyrella ivanovici and came to the conclusion that it had all the features of a cylindroporella. therefore they labelled it cylindroporella ivanovici, wherewith the genus korkyrella was, in fact, contested. – granier & deloffre (1993) designated the genus korkyrella sokač & velić, 1981, nom.nud., and korkyrella ivanovici sokač 1987, nom.nud., as taxonomically invalid for formal reasons, without commenting on their decision. – luperto-sinni & masse (1993b) reminded of their earlier (masse & luperto-sinni, 1989) transfer of korkyrella ivanovici into the genus cylindroporella also emphasize that under the name cylindroporella pedunculata (jaffrezo et al.) they now mean the form presented by sokač & velić (1981) as the type species of the genus korkyrella, where korkyrella ivanovici should be considered as a younger synonym of cylindroporella pedunculata. this short chronological review of different taxonomic treatments of the alga illustrates a number of errors that were made in new descriptions of its detached fragments, its later determinations and assignment to different genera and their species, all of which having as a consequence, the lengthy invalidity of the genus korkyrella and its originally designated type species. according to the icbn, before formally validating the genus korkyrella, it is firstly necessary to give a taxonomically valid status to its type species, designated by sokač & velić (1981). originally, the species was invalidly described by johnson (1965) as salpingoporella texana, because he failed to designate the holotype but instead only illustrated the cotypes (johnson, 1965, pl. 89, figs. 5–9). therefore i propose as the lectotype of salpingoporella texana johnson the oblique section figured in johnson, 1965, pl. 89, fig. 24 geologia croatica 57/1 25sokač: on some peri-mediterranean lower cretaceous dasyclad species... 9, which is, together with other cotypes in thin-section usnm 42468, deposited in the u.s. national museum. the renewed reinterpretation of the genus korkyrella new generic diagnosis the thallus is clearly differentiated into a more or less elongated, swollen and bulbous upper part – the head, and a lower, narrower, part – the stalk. the transition between the two parts is abrupt. the head bears both fertile and sterile branches, whereas the stalk bears only the sterile ones. in the head, fertile and sterile branches alternate in neighbouring whorls, fertile ampoules also have secondary branches. sterile branches in the stalk are also arranged in whorls. remarks the main distinguishing character of the genus korkyrella, that clearly separates that genus from other similar ones, concerns the arrangement and the division of the branches (fig. 2) and can be summarized as follows: korkyrella differs from otternstella and chinianella by the alternating arrangement of fertile and sterile branches, and from cylindroporella, which has an identical arrangement of branches, by the existence of secondary branches on the fertile ampoules. fig. 2 comparison of otternstella, chinianella, cylindroporella, korkyrella and korkyrella texana (johnson) in axial and different tangential sections of the upper fertile part of the thallus (a–c, after granier et al., 1994). 24 geologia croatica 57/1 25sokač: on some peri-mediterranean lower cretaceous dasyclad species... korkyrella texana (johnson) nov. comb. pls. x–xii selected synonymy 1965 salpingoporella texana n.sp. – johnson, p. 719–720, pl. 89, figs. 5–9. 1971 acroporella nissovensis n.sp. – bakalova, p. 58–59, pl. 1, figs. 1–3. 1978 pseudoepimastopora pedunculata n.sp. – jaffrezo, poisson & akbulut, p. 79–80, pl. 2, figs. 1–3, 6, 9; pl. 4, fig. 2 (part); pl. 6, fig. 3 (?part). 1979 cylindroporella barnesii johnson – peybernès & conrad, pl. 2, figs. 4, 6, 5? 1981 korkyrella texana (johnson) – sokač & velić, p. 1–12, text-fig. 1, pls. 1–3. 1982 cylindroporella barnesii johnson – conrad, p. 1–4, pl. 1, figs. 3, 5, 6, 4? 1987 korkyrella ivanovici n.sp. – sokač, p. 11–16, pls. 1–2. 1989 cylindroporella ivanovici (sokač) – masse & luperto-sinni, p. 30–38. 1993b cylindroporella pedunculata (jaffrezo et al.). – luperto-sinni & masse, p. 295–309, pl. 2, figs. 12–15. ?1993 cylindroporella pedunculata (sokač, 1987) – soták & míšík, p. 383–404, pl. 5, figs. 5–7. 1994 cylindroporella pedunculata (jaffrezo, deloffre & akbulut) – bodrogi, bona & lobitzer, pl. 10, figs. 1, 3. 1999 cylindroporella pedunculata (jaffrezo, poisson & akbulut) – bucur, p. 53–72, pl. 2, figs. 15, 18, 21. a a thorough re-description appears necessary after visible contradictions concerning the taxonomic assignment and the validity of this alga, due to its unclear morphology, strong recrystallization, frequent finds of detached fragments of different parts of the thallus, and, generally, the poor state of preservation resulted in different individual interpretations. in addition to the already mentioned characteristically shaped thallus, this alga is distinguished by the rather complex structure of the outer part of the calcareous envelope in the bulbous (“head“) part. the proposed lectotype (johnson, 1965, pl. 89, fig. 9), selected among several cotypes, is represented by an oblique section with heavily recrystallized inner structure, poorly delineated outer surface, and visible alternating arrangement of pores, belonging to two types of branches, in the wall of the axial cavity. on the outer side of the inner wall there are arcuate protrusions directed towards the centre which mark the proximal parts of large fertile branches, with narrow channels of thin sterile branches situated in between them. arcuate protrusions on the inner side of the outer part of the skeleton correspond to the distal ends of the fertile ampoules, as indicated by their more or less wineskin-shaped form. the traces of sterile branches in the lectotype section can only be partially seen in its middle part as tiny pores that alternate in position with larger fertile branches. in other parts of the skeleton they are obliterated by recrystallization. the lectotype section fully corresponds to the oblique sections figured by sokač & velić (1981, pl. 1, fig. 7; pl. 3, figs. 3, 5, 6), which is a strong indication of the taxonomic identity of both materials. the same thing also applies to the sections accompanying the description of pseudoepimastopora pedunculata jaffrezo et al. (1978, pl. 2, figs. 1, 3–6), that also correspond – fully or partially, depending on the state of preservation – to the sections illustrated in sokač & velić (1981, pl. 1, figs. 1–6) and sokač (1987, pl. 1, figs. 1, 4; pl. 2, figs. 1–3), as well as to those in this paper, pl. xi, fig. 6 and pl. xii, figs. 2, 3. also, the sections figured by luperto-sinni & masse (1993b, pl. 2, figs. 12–15) correspond well to those in sokač & velić (1981, pl. 1, fig. 6; pl. 3, figs. 1, 5, 6) or, partly, to those in sokač (1987). all these facts unequivocally indicate that all the above mentioned illustrations, deriving from various periods and localities and differently interpreted by various authors, belong to the same algal species, the characteristics of which may be summarized as follows (see fig. 3, table 3). as has already been emphasized in earlier descriptions, korkyrella texana (johnson) has a thallus that is clearly differentiated into two distinct parts: the upper, bulbous, “head”, and the lower, narrow, stalk, that abruptly passes into the “head” via a short “neck”. the central cavity, stretching from the stalk with a constant diameter, continues into the upper part, where the inner wall is seldom observed, only in rare transverse and oblique sections (pl. xii, figs. 4–8). in the upper, bulbous, part of the thallus (“head”) there are both fertile and sterile branches developed. very weak calcification of the walls of fertile branches and the lack of calcification in the intervening space leads to their almost complete destruction. this results in the apparent existence of two envelopes, an inner one surrounding the axial cavity and an outer one, which forms the outer surface. the stalk bears only sterile branches; thus the “head” can be considered to be the fertile part of the thallus. the distinguishing characteristics of the species within the genus korkyrella, of which it is a typical representative, are the disposition of the branches and the existence of secondary branches on the fertile ampoules. the branches are arranged into very dense whorls. within a whorl, in the upper part of the thallus, sterile and fertile branches alternate. the disposition of sterile and fertile branches in neighbouring whorls is also clearly alternating, as has been graphically shown for the genus cylindroporella by ott (1967) and granier et al. (1994). fertile branches, often called “ampoules” because of their wineskin-like shape, are large, constricted at the base and rounded at the distal end. sometimes they acquire a plump-elongated or irregularly elliptical 26 geologia croatica 57/1 27sokač: on some peri-mediterranean lower cretaceous dasyclad species... shape. they communicate with the main cell through a narrow and short channel, situated in the middle of the base. from the top of the distal surface of each fertile branch (“ampoule”), four secondaries emerge from the same starting point. they are comparatively massive, strongly bent, and thus almost subparallel to the outer surface (pl. xi, figs. 1, 7). viewed in the vertical plane, the angle of their divergence amounts to 50–60º (“below” and “above”), whereas in the horizontal plane (viewed “laterally”) it is smaller, amounting to 30–40º. therefore they often appear like an andrew’s cross (pl. xi, figs. 1, 7). the dense arrangement of fertile branches results in their being tightly pressed against each other, so that their walls are very thin and weakly micritized, which results, in turn, in being frequently destroyed and only rarely can they be visually traced by a thin, dark, micritic layer (pl. x, fig. 1; pl. xi, fig. 1). the spaces that are formed by the rounding of their distal ends and by the constrictions at their bases are somewhat more strongly calcified, which appears as if there is one outer and one inner calcareous envelope (pl. xii, figs. 6, 7). a similar situation exists with the secondary branches of the fertile ampoules, that seem to be immersed in the calcareous mass with their lower parts only, appearing exceptionally as micritized petals in a cross-shaped arrangement (pl. x, fig. 2; pl. xi, figs. 1, 4, 7). the small number of branches in a whorl (8–9) and their large size makes it impossible to see, in shallow tangential (cortical) sections, more than one or, exceptionally, two sections of the cross-shaped arrangement of secondary branches of neighbouring, alternately situated sporangia (pl. xi, fig. 7, central part of the picture, arrow; pl. xi, fig. 4, top part of the picture, arrow) and weak micritization of the surface membrane. sterile branches, in their proximal parts up to a half or two thirds of their length, are very thin and squeezed between the fertile ampoules, with weakly calcified envelopes. therefore they appear, in sections, as tiny circular pores with micritized margins (pl. xi, fig. 1). toward their distal ends they gradually broaden and are somewhat more heavily calcified (pl. xi, fig. 1, going up and down from the centre of the picture). at their very distal ends, they seem to extend above the upper surface of the secondary branches (on the fertile ampoules), they appear rhombic in section, with more or less stretched sides. some very distal sections of the secondary branches (pl. xi, fig. 1) may indicate their further branching, but this cannot be unequivocally ascertained. similarities and differences from the chronological review of various determinations given above, it can be seen that this alga was most frequently assigned to the genus cylindroporella. this was due to the occasional and not very clearly visible alternating arrangement of two types of pores, of different dimensions, in neighbouring whorls. of these, the larger ones were thought to represent fertile, and the smaller ones sterile branches. however, the newly observed morphological characteristics – well developed secondary branches, in a cross-shaped disposition, growing out of fertile ampoules – gave this alga a new qualitative feature, by which it can be, in appropriate sections (i.e., those cutting the “head”), clearly and unequivocally distinguished from otherwise similar cylindroporella species. the identification is more difficult if only sections of the stalk are available, which may appear similar to some salpingoporella species with which they often jointly occur in the same sample; in such cases, the acrophorous type of branches may be taken as an indication suggesting a probable assignment of such sections to korkyrella. stratigraphic position in order to assess the stratigraphic range of korkyrella texana, one must take into account all its fig. 3 schematic reconstruction of korkyrella texana (johnson). (a) cross section; (b) longitudinal section; (c) outer thalus surface; (d) head passing into the handle; (e) handle. 26 geologia croatica 57/1 27sokač: on some peri-mediterranean lower cretaceous dasyclad species... occurrences, dispersed at numerous localities all over the mediterranean realm, as well as the material illustrated by johnson (1965), which is said to derive from the upper part of the edwards formation (albian). in contrast, the great majority of later finds, (disregarding the different taxonomic assignments by various authors – see above), seem to be of a more or less identical age, corresponding to the barremian– lower aptian. however, some sections which are said to be of cenomanian age (conrad, 1982, pl. 1, figs. 4–6) and which could possibly be assigned to that species (but are very poorly preserved), or perhaps to some other species of that genus (which is, for the time being, uncertain), indicate the possibility of a broader stratigraphic range. therefore i will restrict my comments here only to those localities in the dinarides at which the stratigraphic position of the species is well documented by rich microfossil assemblages and i will leave aside all uncertain identifications, which also need a re-examination of their stratigraphic position. in the original description of the genus korkyrella, at the type locality (brna, korčula island), sokač & velić (1981) mention the following accompanying assemblage: praturlonella dalmatica (sokač & velić), triploporella marsicana praturlon, later supplemented by triploporella baciliformis sokač and salpingoporella heraldica sokač, and the first appearance of palorbitolina lenticularis (blumenbach). at another locality, on the west bank of the neretva river, upstream of mostar, it is accompanied by falsolikanella danilovae (radoičić), falsolikanella nerae (dragastan et al.), salpingoporella cf. genevensis (conrad), salpingoporella dinarica radoičić, cylindroporella elliptica bakalova, and others. on mt. biokovo, there are several localities with korkyrella texana. among those, the richest microfossil assemblage has been found on the road between the vošac mountain hut and the sv. jure peak. a bed lying immediately below the first appearance of palorbitolina lenticularis is full with deposited algal remains: particularly frequent sections of salpingoporella muehlbergii (lorenz), salpingoporella verticillata (sokač & nikler), salpingoporella patruliusi bucur, biokoviella robusta (sokač), cymopolia velici sokač & nikler, cylindroporella lyrata masse & luperto-sinni, triploporella? sarda jaffrezo et al., neomeris cretacea steinmann, suppiluliumaella polyreme elliott, and others. in western istria, well-preserved, partly isolated (washed out) specimens of this species (sokač, 1987, pl. 15, figs. 5–8) have been found in platy limestone, almost immediately below the thickbedded limestone known commercially as ‘giallo d’istria’ (istrian yellow, that, in addition to abundant bacinella irregularis, contain rare sections of palorbitolina lenticularis, with, in the lowest levels, the dimensions of head in mm: maximum observed length (l) 10 outer diameter (d) 0.52–1.46 inner diameter (d) 0.08–0.33 relation d/d 0.18–0.24 distance between sporangial whorls (h) 0.14–0.30 diameter of sporangia (p) 0.10–0.24 length of sporangia (l) 0.20–0.45 number of sporangia per whorl (w) 8–9 diameter of secondary branches (p’) 0.12–0.16 length of secondary branches (l’) 0.20–0.30 number of secondary branches on a sporangium (w”) 4 diameter of sterile branches (p”) 0.07–0.14 length of sterile branches (l”) 0.58 number of sterile branches per whorl (w”) 8–9 number of secondaries on a sterile branch (w”’) ?(4) dimensions of stalk in mm: maximum observed length (l) 2.4 outer diameter (d) 0.40–0.48 inner diameter (d) 0.10–0.20 relation d/d 0.25–0.45 distance between whorls (h) 0.06–0.10 diameter of branches (p) 0.04–0.06 length of branches (l) 0.12–0.18 number of branches per whorl (w) ? table 3 main biometric parameters of korkyrella texana (johnson). 28 geologia croatica 57/1 29sokač: on some peri-mediterranean lower cretaceous dasyclad species... pachyodont bivalve toucasia sp. the best preserved specimens, which, indeed, enabled the emendation of the genus korkyrella (pl. x, figs. 1, 2; pl. xi, figs. 1, 4, 7), have been found at the locality of grabrk, near the town of ogulin (central croatia), where they have been found together with neomeris cretacea steinmann, ciptocampylodon fontis (patrulius), rare salpingoporella dinarica radoičić, more or less abundant palorbitolina lenticularis, and numerous pachyodont bivalve debris. the above review of fossil occurrences of this species at several widely dispersed localities in the karst dinarides, reliably indicate that the stratigraphic range of korkyrella texana in the dinaric mountains corresponds to the barremian–lower aptian. it remains, however, an open question whether its occurrence at new localities, provided a secure identification and well documented stratigraphic position are available, will perhaps necessitate a revision, i.e. broadening, of the stratigraphic range as given above. acknowledgements this paper is based on samples that were collected by several colleagues who participated in the field work, i.e. in the mapping of the lower cretaceous deposits, to all of whom i am greatly indebted. they are: đuro benček, josip bukovac, ivan galović, and ivo velić. i am particularly grateful to ivo velić for his determination and stratigraphic interpretation of the accompanying foraminiferal assemblages. i also thank tonći grgasović for lengthy discussions and his critical remarks on earlier drafts of this paper. i am grateful to the reviewers, ivan gušić and marc a. conrad, who critically read the manuscript, indicated some errors, and gave several useful remarks that clearly improved the presentation. i must emphasize that my discussion concerning the neomeris species described by radoičić (2002) and my conclusion that they should be considered younger synonyms of n. cretacea has been added to the text after the suggestion of m.a. conrad and the reviewers did not have the opportunity to see, and to comment on, it. i must also emphasize the difference in opinions between m.a. conrad and myself concerning the form which served as the basis for the emendation of the genus acroporella praturlon & radoičić (1974); in my opinion, it is a new species, i.e., biokoviella gusici. in his review, m.a. conrad expressed the opinion that b. gusici is a younger synonym of acroporella radoicici. in spite of this reviewer’s remark, i decided to stick to my opinion. it may be debatable whether my arguments are conclusive, but it seems unacceptable to me to unite forms which, in spite of being superficially similar, show some obvious differences. i hope that this question will be the subject of further research, and more arguments will be put forward which will support either opinion. 3. references bakalova, d. (1971): certain fossil algae from the rousse formation (aptian) in north bulgaria.– rev. bulg. geol. soc., 31/1, 55–62. barattolo, f. (1990): remarks on neomeris cretacea steinmann (chlorophyta, dasycladales) from the cretaceous of orizaba (type-locality), mexico.– boll. soc. paleont. ital., 29/2, 207–218. bassoullet, j.p., bernier, p., conrad, n.a., deloffre, r. & jaffrezo, m. (1978): les algues dasycladales du jurassique et du crétacé [dasycladal algae of the jurassic and cretaceous – in french].– geobios, mém. spec., 2, 1–330. bodrogi, i., bona, j. & lobitzer, h. (1994): vergleichende untersuchung der foraminiferen und kalkalgenassoziationen der urgon-entwicklung der schrattenkalks in vorarlberg (österreich) und der nagyharsany kalkstein formation des villany-gebirges (ungar) [comparative study of foraminiferal and calcareous algal assemblages of urgonian facies of schrattenkalk limestones in vorarlberg (austria) and nagyharsany limestone formation of villany mts. (hungary) – in german].– jubilaums. 20 jahre geol. zusammenarbeit osterreich-ungar., 225–283. bucur, i.i. (1999): lower cretaceous dasyclad algae from the padurea crainbui massif (northern apuseni mountains, romania).– acta paleont. romaine, 2, 53–72. conrad, m.a. (1982): comments on korkyrella and other dasycladaceae.– rev. paléobiol., 1/1, 1–3. conrad, m.a. & peybernés, b. (1976): hauterivian– albian dasycladaceae from the urgonian limestones in the french and spanish eastern pyrenees.– geol. romana, xv, 175–197. elliot, g. (1968): three new tethyan dasycladaceae (calcareous algae).– palaeontology, 11/4, 491–497. granier, b. & deloffre, r. (1993): inventaire critique des alques dasycladales fossiles. iiº partie: les alques dasycladales du jurassique et du cretace [revision of fossil dasyclad algae. 2nd part: dasyclad algae of jurassic and cretaceous – in french].– rev. de paléobiol., 12/1, 19–65. granier, b., masse, j.p. & berthou, p.y. (1994): heteroporella lepina praturlon, 1967, revisited (followed by taxonomic notes on the so-called “heteroporella” species).– beiträge zur paläeontologie, 19, 129–141. jaffrezo, m., poisson, a. & akbulut, a. (1978): bey dağlari tipi serilerin alt kretase algleri (bati toroslar, türkiye) [lower cretaceous algae of bey dağlari series (eastern taurides, turkey) – in turkish].– bull. mineral. res. explor. inst. turkey, 91, 76–88. johnson, j.h. (1965): three lower cretaceous algae new to the americas.– journ. paleont., 39/4, 719–730. luperto-sinni, e. & masse, j.p. (1993a): biostratigrafia dell’aptiano in facies di plattforma carbonatica delle murge baresi (puglia – italia meridionale) [biostratigraphy of aptian carbonate platform facies of the murge baresi (puglia – central italy) – in italian].– riv. ital. paleont. strat., 98/4, 403–424. 28 geologia croatica 57/1 29sokač: on some peri-mediterranean lower cretaceous dasyclad species... luperto-sinni, e. & masse, j.p. (1993b): the early cretaceous dasycladales from the apulia region (southern italy): biostratigraphic distribution and paleobiogeographic significance.– in: baratolo, f., de castro, p. & parente, m. (eds.): studies on fossil benthic algae. boll. soc. paleont. ital., spec. vol., 1, 295–309. masse, j.p. & luperto-sinni, e. (1989): cylindroporella lyrata, nouvelle espèce de dasycladale de l’aptien inférieur du domaine périméditeranéen nord occidental (cylindroporella lyrata, new species of dasycladal algae from the lower aptian of the ne perimediterranean domain – in french).– rev. micropaléont., 32/1, 30–39. ott, e.v. (1967): dasycladaceen (kalkalgen) aus der nordalpinen obertrias [dasycladaceans (calcareous algae) from northern alps upper triassic – in german].– mitt. bayer. staatssamml. paläont. hist. geol., 7, 205–226, münchen. peybernès, b. & conrad, m.a. (1979): les algues du crétacé inférieur de hongari (lower cretaceous algae of hungary – in french).– bull. centr. rech. explor.– prod. elf-aquitaine, 3/2, 743–752. praturlon, a. (1964): calcareous algae from jurassic– cretaceous limestones of central apenines (southern latium–abruzzi).– geol. romana, iii, 171–202. praturlon, a. & radoičić, r. (1974): emendation of acroporella (dasycladaceae).– geol. romana, xiii, 17–20. radoičić, r. (2002): dasycladalean algae from the lower cretaceous of the mt. rujen (vardar zone, macedonia).– rev. paléobiol., 21, 7–19. schlagintweit, f. (1991): allochtone urgonkalke im mitteren abschnit der nordlichen kalkalpen: facies, paläontologie und palägeographie [allochthonous urgonian limestone in the central part of the northern calcareous alps: facies, palaeontology and palaeogeography – in german].– münch. geowiss. abhaundlungen a (geol. pal.), 20, 1–120. sokač, b. (1987): on some controversial dasyclad genera and species and their stratigraphic position in the lower cetaceous deposits of the dinarides.– geol. vjesnik, 40, 9–38. sokač, b. (1989): macroporella aptiensis n.sp. (calcareous algae, dasycladales) from the peri-reefal lower aptian limestones in western croatia.– geol. vjesnik, 42, 1–6. sokač, b. (1993): salpingoporella robusta n.sp. (calcareous algae; dasycladales) from the upper dogger of southern dalmatia (croatia).– geol. croatica, 46/2, 175–180. sokač, b. (1996): taxonomic review of some barremian and aptian calcareous algae (dasycladales) from the dinaric and adriatic karst regions of croatia.– geol. croatica, 49/1, 1–79. sokač, b. & nikler, l. (1973): calcareous algae from the lower cretaceous of the environs of nikšić, crna gora (montenegro).– paleont. jugoslavica, 13, 1–57, zagreb. sokač, b. & velić, i. (1981): korkyrella n.gen. (dasycladaceae) from the upper barremian and lower aptian of the island of korčula.– paleont. jugoslavica, 24, 1–12, zagreb. soták, j. & míšík, m. (1993): jurassic and lower cretaceous dasycladalean algae from the western carpathians.– in: baratolo, f., de castro, p. & parente, m. (eds.): studies on fossil benthic algae. boll. soc. paleont. ital., spec. vol., 1, 383–404. steinmann, g. (1899): ueber fossile dasycladacean vom cerro escamela, mexico [on the fossil dasycladaceans from cerro escamela, mexico – in german].– bot. zeit. berlin, 57/8, 137–154, leipzig. manuscript received june 09, 2003. revised manuscript accepted may 04, 2004. 30 geologia croatica 57/1 31 plate i 1–8 cylindroporella lyrata masse & luperto-sinni 1 longitudinal section, kj–18/54, x17. 2 oblique–tangential section, kj–18/29, x22. 3 oblique section, kj–18, x22. 4 oblique–tangential section, kj–18/22, x17. 5–6 oblique sections; fig. 5, kj–18/224; fig. 6, kj–18/111, x34. 7–8 transverse sections; fig. 7, kj–18/32; fig. 8, kj–18/212, x34. mt. biokovo, upper barremian. 30 geologia croatica 57/1 31sokač plate i 32 geologia croatica 57/1 33 plate ii 1–8 cylindroporella lyrata masse & luperto-sinni 1 oblique section, kj–18/208, x22. 2 oblique section; groups of cysts are visible in the pores of fertile ampoules; kj–18/124, x34. 3 oblique section of the lower part of the thalus, near the stalk; kj–18/25, x22. 4–5, 8 oblique sections; fig. 4, kj–18/172; fig. 5, kj–18; fig. 8, kj–18/194, x22. 6 oblique section, kj–18/230, x22. 7 transverse section, kj–18/223, x34. mt. biokovo, upper barremian. 32 geologia croatica 57/1 33sokač plate ii 6 34 geologia croatica 57/1 35 plate iii 1–8 biokoviella robusta (sokač) nov.comb. 1, 3–4 oblique–tangential sections, fig. 1, kj–18/241; fig. 3, kj–18/245; fig. 4, kj–18/55; x22. 2 tangential section, kj–18/28, x22. 5–7 oblique sections; fig. 5, kj–18/58; fig. 6, kj–18/18; fig. 7, kj–18/107; x22. 8 longitudinal section, kj–18/210, x22. mt. biokovo, upper barremian. 34 geologia croatica 57/1 35sokač plate iii 36 geologia croatica 57/1 37 plate iv 1–8 biokoviella robusta (sokač) nov.comb. 1 oblique section, kj–18/141, x34. 2 oblique section; a tuft with 6 pores of secondary branches is visible in the upper part, kj–18/141, x34. 3 oblique section; specimen with very large cylindrical pores of primary branches, each bearing relatively large, separately grown, secondary branches; kj–18/108, x34. 4 transverse section; specimen with irregular (deformed) primary branch, possibly triple divided; kj–18/117, x34. 5 transverse–oblique section; specimen with large primary branches bearing both tufts and separately grown secondary branches; kj–18/57, x34. 6 transverse section; specimen with large primary branches bearing both tufts and separately grown secondary branches; kj–18/203, x34. 7 transverse section; specimen with large primary branches, bearing separately grown secondary branches and possible tertiary branches; kj–18/240, x34. 8 oblique–tangential section; possible club-shaped primary branches; kj–18/58, x22. 9–10 transverse sections; possible tuft-growing of secondary branches; fig. 9, kj–18/244; fig. 10, kj–18/90, x34. mt. biokovo, upper barremian. 36 geologia croatica 57/1 37sokač plate iv 38 geologia croatica 57/1 39 plate v 1–8 biokoviella robusta (sokač) nov.comb. 1 oblique, partly tangential section; specimen with fusiform to club-shaped primary branches; kj–18/67, x22. 2 oblique, partly tangential section; specimen with phloiophorous primary branches, approaching the similar species biokoviella gusici n.sp.; kj–18/146, x34. 3 transverse and transverse–oblique sections; specimens with variously shaped primary branches, and with a variable number of branches per whorl; kj–18/247, x34. 4–5 transverse sections; irregular growth of the secondary branches is visible on fig. 5; fig. 4, kj–18/244; fig. 5, kj–18/170, x34. 6 oblique sections; showing differences between specimens, both in dimensions and in the density of branches; kj–18/15, x22. 7 transverse sections; showing the pronounced variability, both in the shape of the primary branches, and in the number of the branches per whorl; kj–18/247, x14. 8 fragment of the oblique section; tuft-growing secondary branches on the right side of the specimen; kj–18/ 215, x34. mt. biokovo, upper barremian. 38 geologia croatica 57/1 39sokač plate v 40 geologia croatica 57/1 41 plate vi 1–7 biokoviella gusici n.sp 1–2 oblique–tangential sections; fig. 1, kj–18/30; fig. 2, kj–18/5, x22. 3 tangential section, kj–18/28, x22. 4–6 oblique sections; fig. 4, kj–18/139; fig. 5, kj–18/33; fig. 6, kj–18/91; x34. 7 oblique section, kj–18/22, x22. mt. biokovo, upper barremian. 40 geologia croatica 57/1 41sokač plate vi 42 geologia croatica 57/1 43 plate vii 1–7 biokoviella gusici n.sp 1–6 oblique sections; fig. 2 = holotype; clearly visible secondary branches in figs. 2–4; fig. 1, kj–18/124; fig. 2, kj–18/185; fig. 3, kj–18/98; fig. 4, kj–18/138; fig. 5, kj–18/159; fig. 6, kj–18/193, x34. 7–12 transverse sections; phloiophorous primary branches with tufts of secondary branches are clearly visible in figs. 8–11; fig. 7, kj–18/152; fig. 8, kj–18/83; fig. 9, kj–18/220; fig. 10, kj–18/182; fig. 11, kj–18/ 106; fig. 12, kj–18/15, x34. 13 tangential section; tiny pores of secondary branches dispersed around large pores of primary branches; kj–18/182, x34. 14 oblique section; specimen with fusiform primary branches and short phloiophorous secondary branches; kj–18/8, x22. mt. biokovo, upper barremian. 42 geologia croatica 57/1 43sokač plate vii 44 geologia croatica 57/1 45 plate viii 1–10 neomeris cretacea steinmann 1 longitudinal section; fertile ampoules might be recognised at the lower right part of the thalus; gd 22/1, x22. 2, 4 oblique sections; no fertile ampoules visible; fig. 2, gd–23/5, x22; fig. 4, gd–23/1, x17. 3 oblique section; separate fertile ampoules are visible; gd–23/8, x22. 5–6 oblique sections; specimens with well developed fertile ampoules; fig. 5, gd–23/25, x 17; fig. 6, gd–23/ 28, x22. 7 transverse section; no fertile ampoules visible; there are indications of third-order branches on some sterile branches; gd–23/23, x34. 8 oblique section; no fertile ampoules visible; gd–23/14, x22. 9–10 transverse sections; no fertile ampoules visible; very thin secondary branches; fig. 9, gd–23/9; fig. 10, gd–23/8; x22. near grabrk village, lower aptian. 44 geologia croatica 57/1 45sokač plate viii 46 geologia croatica 57/1 47 plate ix 1–10 neomeris cretacea steinmann 1 longitudinal section; fertile ampoules are clearly visible in the thalus walls; b–127/4, x17. 2–3 oblique sections; fertile ampoules are visible; fig. 2, b–127/7; fig. 3, b–127/5; x17. 4–5 oblique sections; fertile ampoules are visible in some parts of the calcareous thallus; fig. 4, gd–23/19, x 14; fig. 5, gd–23/20, x17. 6 tangential section; arrangement of the pairs of sterile branches are visible; indication of the third-order branches on the top of the figure; gd–23/33, x34. 7–8 oblique sections; specimens with thin sterile branches and poorly visible fertile ampoules; fig. 7, gd–23/ 15, x17; fig. 8, gd–23/13, x22. 9 transverse, slightly oblique section; fertile ampoules are clearly visible; b–127/6, x22. 10 transverse section; the phloiophorous shape of the sterile branches is clearly visible; b–127/1, x22. sample b–127: central mt. biokovo near saranč, boundary level barremian–lower aptian. samples gd–22, 23: near grabrk village, lower aptian. 46 geologia croatica 57/1 47sokač plate ix 48 geologia croatica 57/1 49 plate x 1–7 korkyrella texana (johnson) 1 deeper tangential section; see alternating arrangement of the sporangia and sterile branches in the neighbouring whorls; gd–24a, x17. 2 shallow tangential section; note large pores of secondary branches in cross-shaped arrangement (“andrews cross”); their alternating arrangement is visible in the lower part of the figure; gd–23, x17. 3 longitudinal–tangential section; alternating arrangement of sterile branches is visible in the tangential part of the section (lower part of the figure), as well as alternating cross-shaped arrangement of secondary branches; gd–24b/1; x17. 4 oblique section; cross-shaped arrangement of secondary branches is visible at the top and at the bottom of the figure; gd–23/2x14. 5 longitudinal section; see transition between the “head” and the “stalk” in the lower part of the figure; kj– 18/1, x17. 6–7 oblique sections; fig. 6, gd–23/2, x34; fig. 7, kj–18/104, x17. samples gd–23, 24a–b: near grabrk village, lower aptian. sample kj–18: mt. biokovo, upper barremian. 48 geologia croatica 57/1 49sokač plate x 50 geologia croatica 57/1 51 plate xi 1–7 korkyrella texana (johnson) 1 tangential section; see the alternation of sterile and fertile branches in the whorl, as well as their alternating position in the neighbouring whorls; note also the alternating position of the cross-shaped arrangement of the secondary branches in the outer tangential part of the section (lower part of the figure); and the rhombic shape of the distal end of sterile branches at the top and at the bottom of the figure; gd–24b/2, x22. 2 oblique section; gd–23, x22. 3 oblique section passing to the tangential section; kj–18/56, x22. 4 outer tangential section; note the alternation of sterile and cross-shaped arranged secondary branches in the neighbouring whorls; also poorly visible partial overlapping of some secondary branches at the top of the figure; gd–24b/2, x22. 5 tangential section; sal–372, x22. 6 oblique section; note the transition between the “head” and the “stalk” in the lower part of the figure sal– 372/25, x22. 7 tangential section passing to the longitudinal section; clearly visible arrangement of sterile and secondary branches in the central part of the figure, as well as their alternating position in the neighbouring whorls; gd–24b/1, x22. samples gd–23, 24b: near grabrk village, lower aptian. sample sal–372: near salakovac village, north from mostar (bosnia and herzegovina), upper barremian. 50 geologia croatica 57/1 51sokač plate xi 52 geologia croatica 57/1 53 plate xii 1–7 korkyrella texana (johnson) 1 oblique section; kj–18/201, x22. 2 oblique section; see the transition between the “head” and the “stalk” in the lower part of the figure sal– 372/2, x 17. 3 various sections; gd–24a, x14. 4 tangential section; clearly visible transition between the “head” and the “stalk”; in the upper part (head) sterile and secondary branches are visible; in the lower part (stalk) only sterile branches are visible; sal– 372/2, x 34. 5 oblique and tangential section of the stalk (= acroporella nisovensis bakalova); only sterile branches are visible; kj–18/1, x34. 6, 8–10 transverse sections; inner and outer calcareous “envelopes” are separated due the absence of calcification in the middle part of the thalus; note pores of fertile and sterile branches in the inner envelopes; fig. 6, sal–372/25, x34; fig. 8, kj–18/116, x34; fig. 9, sal–372/2, x34; fig. 10, sal–372/2, x22. 7 oblique section; sal–372/16, x34. sample kj–18: mt. biokovo, upper barremian samples gd–24: near grabrk village, lower aptian. sample sal–372: near salakovac village, north from mostar (bosnia and herzegovina), upper barremian. 52 geologia croatica 57/1 53sokač plate xii 54 geologia croatica 57/1 gc 58-1.indb 1. introduction the mala mlaka well field is the largest near zagreb and is very important for the city’s water supply. the field is located on the right sava river bank, in the immediate vicinity of the new zagreb urban complex. the vicinity of the neighbouring industry, agricultural land, illegal gravel pits and dumpsites that developed in abandoned gravel pits threaten the quality of the well field groundwater. the croatian groundwater recording and management project clearly determined degradation in the groundwater quality in the zagreb aquifer system. continuous and occasional groundwater contamination was detected in a large number of observation wells. statistical indicators of groundwater geochemical characteristics in a quaternary aquifer from the mala mlaka well field catchment area (zagreb, croatia) zoran nakić, siniša horvat and andrea bačani the article uses results of numerical simulation of the groundwater flow in the zagreb aquifer system that were employed in determination of the mala mlaka well field catchment area under different hydrological conditions. the model results were complemented with geological and hydrogeological interpretation of the southern border of the catchment area (bačani & šparica, 2001). in the model, the southern border was determined to be immediately adjacent to the southern border of the third protection zone, since the number of sites on which groundwater tables are measured is small. the results of the numerical simulation were used as a background for further research into groundwater quality. the pollution sources were recorded in the catchment area (fig. 1), primarily within the protection zone borders (fig. 2). results of the chemical analyses for the period 1994–2000 were provided by the water supply and drainage utility. the analysis has revealed that: – the observation well sites sampled for chemical and bacteriological analyses are mostly located within the borders of the mala mlaka well field protection zones; – the sampling was generally carried out on a monthly basis. this article reports on basic hydrogeochemical processes evolving in a shallow water-bearing layer in the mala mlaka well field catchment area. the hydrogeochemical facies, i.e. the main water types were determined. the groundwater quality time series were analysed to confirm significant hydrogeochemical processes in the catchment area. the analysis was used to determine the time series for significant chemical elements and compounds from the groundwater quality data for the period 1994–2000. in order to evaluate individual impacts of the pollution sources on the groundwater chemistry, the similarities and interrelationships of the observation well sites hydrochemical data were investigated. the multivariate statistical analyses were used, i.e. factor analysis, cluster analysis and multidimensional scaling (mds) analysis. multivariate analysis is based on carrying out simultaneous measurement of several variables on geologia croatica 58/1 87–99 9 figs. 5 tabs. zagreb 2005 key words: groundwater geochemistry, groundwater protection, statistical analyses, mala mlaka well field, zagreb, croatia. university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, hr-10000 zagreb, croatia; e-mail: znakic@rgn.hr abstract high concentrations of sodium, potassium, nitrates and sulphates in the groundwater in the mala mlaka well field catchment area confirm the impact of agricultural activities on water chemistry. analysis of time trends has shown that a decrease in inorganic components (nitrates and sulphates), which are sensitive to changes in oxidation/ reduction conditions in an aquifer, are caused by infiltration of oxygen-rich water rich in organic matter into the aquifers. oxygen content reduction due to oxidation of the organic matter causes oxygen deprivation in the groundwater and consequently a reduction in nitrate and sulphate levels. an increase in chloride levels in the groundwater during 1994–2000 is a consequence of human activities in the catchment area. multivariate statistical analyses, i.e. factor analysis, cluster analysis and multidimensional scaling (mds) analysis have shown that the registered pollution sources in the catchment area, particularly illegal dump sites, cause degradation of the groundwater quality in some sites. this impact is detected over a distance of several hundred metres downstream from the registered pollution sources. 88 geologia croatica 58/1 a sample. a primary goal is to determine interrelationships of the measured variables of the tested samples (brown, 1998). in the article, the chemical analysis data from 2000 were used. statistica for windows 5.1 software package (statsoft, 1995) was used for statistical analyses. 2. site and hydrogeological relations the mala mlaka well field is located in the southern part of zagreb, on the right sava river bank, in the immediate vicinity of an urban area. it was designed in 1938, and the first wells were put into operation in 1964 (čakarun et al., 1987). the well field has 10 dug and 6 drilled wells with an average yield of about 1400 l/s. the geological texture is characterized by younger sediments blended in the sava alluvium, i.e. the sediments deposited by the sava river during the last 10,000 years while it cut its course in this area1. these are holocene sediments that reach depths of approximately 35 m in the mala mlaka area and are dominated by gravel and sand of the first and the second alluvial terrace. the youngest holocene sediments are exceptionally important since they form the main aquifer, which is of particular importance for the water supply fig. 1 the catchment area and the sanitary protection zones of the mala mlaka well field. 1 saftić, b. (1999): geologija – litostratigrafska podloga [geology – lithostratigraphic basis – in croatian].– unpubl. report on works performed in 1999, vol. 4/i, hrvatske vode, rgnf, 3–8. 89nakić, horvat & bačani: statistical indicators of groundwater geochemical characteristics... of the greater zagreb. at greater depths, deeper aquifers occur in middle and upper pleistocene strata, with frequent lateral and vertical alterations of gravel, sand and clay. generally speaking, two regular phenomena have been noticed in the zagreb aquifer area as regards spreading of the holocene deposits: (a) a decrease in thickness outwards from the sava river, and (b) an increase in thickness from west to east (borčić et al., 1968). sediments of the second alluvial terrace consist of alternating coarsely grained gravel and sand. the petrographic composition of the pebbles is different, but carbonate rock pebbles are most frequently encountered. lithologically, the composition of the first alluvial terrace sediments is dominated by coarsely grained gravel mixed with sand. in the eastern and south-east areas, the sediment composition includes clay mixed with sand and silt (bačani & šparica, 2001). the groundwater flow direction during high and low water tables is nw–se (fig. 2). an average difference between the groundwater tables during high and low tables at the observation well sites is 1.5 to 2 m. 3. the mala mlaka well field catchment area the mala mlaka well field catchment area was determined within the croatian groundwater recording and management project, along with catchment areas of another four zagreb well fields: zapruđe, velika gorica, sašnjak and petruševec. fig. 2 groundwater sampling sites and impacts in the mala mlaka well field catchment area. 90 geologia croatica 58/1 the catchment areas were determined in two ways: – graphically, by using data on the groundwater tables, and – from the numerical simulation results. the catchment area boundaries were graphically determined by delineating the groundwater flow direction on the contour line maps, during low and high groundwater tables (jones, 2001). the resulting boundaries of the zagreb well field sites are for: (a) high water tables, on march 9, 1995, (b) low water tables, on april 2, 1998. the catchment areas of the zagreb well fields were numerically determined on the basis of the results obtained by numerical simulation conducted using visual modflow software (by waterloo hydrogeologic inc.). after verification for these periods, the selected conceptual model was used to observe the catchment area changes depending on the sava river water levels in 1995 (fig. 3). 4. statistical analyses in the article, time series analysis and multivariate statistical analyses: factor analysis, cluster analysis and multidimensional scaling analysis (mds ) are used. the time series analysis is used to determine time trends from the groundwater quality data. the determined trends are used to explain geochemical processfig. 3 the mala mlaka well field catchment area at the time of low and high groundwater tables. 91nakić, horvat & bačani: statistical indicators of groundwater geochemical characteristics... es and potential groundwater contamination risks. the analysis usually consists of determining trend statistics for individual sites. such an approach demands an adequate continuous data series. depending on the length of the analyzed series and their homogeneity, a specific statistical analysis is used to accept or reject the statistical trend results. in this article, a different approach was taken that allows determination of a common trend for a group of sites inside a homogenous area. the analysis comprises several steps: (1) determination of spearman rank correlation coefficients for water quality and time variables per observation well. each well is an identifiable sub-sample of a population inside of homogeneous area. the correlation coefficients are calculated statistics per sub-sample which are used to determine the sample distribution of that statistic. (2) determination of the hypothetical null-distribution of parameters for the observation wells group under consideration. this theoretical distribution is derived from a reference population with a given population value and can be formed by drawing an infinite number of samples of definite size from this population (frapporti et al., 1991; frapporti, 1994). (3) testing a sample distribution against theoretical null hypothesis distribution for equality by χ2 test. (4) depending on the critical value of the χ2 test, the existence of a significant statistical trend is either accepted or rejected. the above analysis uses spearman rank correlation coefficient, which is a robust non-parametric equivalent of pearson correlation coefficient. this correlation statistic is used primarily because of the fact that a time variable, and often a chemical parameter as well, are not normally distributed according to normal or gauss distribution principles. the theoretical null hypothesis distribution is defined by all possible combinations of ranks xi and yi for n observations (frapporti et al., 1994). in the article, a distribution approximation procedure was carried out, using the student–t test distribution with n-2 degrees of freedom (kendall & stuart, 1961; frapporti et al., 1994): t = √[(n-2) rs 2]/√(1rs 2) (1) advantages of this approach to trend determination include: – the analysis can include the maximum possible number of observation well analysis, regardless of the statistical significance of the trend results obtained for individual locations, – the statistical trend distribution study enables the use of low-reliability trends for certain sites for high-reliability determination of trends for a group of observation wells, and – defining multiparametric trends of a group enables significant geochemical processes and pollution/contamination events to be determined over the entire homogenous area. factor analysis attempts to simultaneously explain relationships between several variables in order to find more simple relations that ensure an insight into a hidden data structure (suk & kang-kun, 1999). these simple relationships are expressed through a new set of variables called factors, which retain the maximum amount of information and show the interrelationships of the variables. the most important parameters obtained by factor analysis are communality, factor loading, eigenvalue and the sum of the explained variance. communality is part of the variance explained by the common factors; factor loadings describe the extent of correlation between the factors and the original variables; eigenvalue is an quantity of variance explained by a particular factor, and the sum of the explained variance is the total quantity of variance obtained from the resulting eigenvalues (brown, 1998). here, the data on all the variables are standardized as mean value 0 and variance 1 to avoid problems with different variances of variables, which might affect determination of the factor loadings. the factor scores from factor analysis were used as input data for cluster analysis. the procedure had already been carried out on an example given by suk & kang-kun (1999), and the objective is to reduce those variables and factors that are not significant for explanation of the hydrogeochemical processes. cluster analysis is a method used for grouping individual variables or samples so that, depending on the measured characteristics, the distance between individual groups is maximized. cluster analysis differs from other classification methods in as much as the number and characteristics of individual groups are not known before the analysis, so they are derived directly from the data (brown, 1998). in this article, the hierarchical tree clustering method is used to produce a graphical representation of individual groups using dendograms. specifically, the ward method of hierarchical tree clustering is used based on variance analysis to assess the distance between the clusters (ward, 1963; statsoft, 1995). multidimensional scaling (mds) is a form of analysis in which dimensionality is reduced, and it is based on the distance between the points. the result is expressed as a reduced number of dimensions and used to present the data in a way which causes minimum distortion of the original data (brown, 1998). the input data in mds may be matrices of similarity or dissimilarity, and the correlation matrices. the input data used in the article are the data from the distance matrix, obtained by transposition of the nxp matrix of factor scores obtained by factor analysis into a nxn 92 geologia croatica 58/1 matrix. the procedure is intended to use factor analysis to explain the structure of the observed variables and mds analysis to explain the differences between individual samples. 5. results and discussion the hydrogeochemical facies analysis has shown that the groundwater in the mala mlaka well field catchment area mostly belongs to a ca–mg–hco3 type of water (fig. 4). the analysis has encompassed the observation well sites with filters installed in the first and second water bearing layer. inorganic quality indicators were used in analysis of the time series of the groundwater quality data for the mala mlaka well field catchment area. from examination of the data, indicators were determined which were monitored in most observation well sites in 2000. these indicators are: dissolved oxygen, nitrates, chlorides, sulphates, dissolved carbon dioxide, sodium, potassium, iron, manganese and lead. the trend analysis determined significantly positive trends for chlorides, sodium and potassium and significantly negative trends for dissolved oxygen, nitrates and sulphates (table 1). results of χ2 test also indicate a positive trend for manganese. however, the review of the available data has shown highly pronounced changes in the manganese concentration distribution before and after 1998. this is probably due to the change in heavy metal testing methods from 1998, when atomic absorption spectrophotometry (aas) was replaced by icp – inductively coupled plasma–mass spectrometry. agricultural activities in the mala mlaka well field catchment area are intensive, and the groundwater contamination sources are numerous (fig. 2). relatively high concentrations of sodium, potassium, nitrates and sulphates in the groundwater (fig. 5) confirm the impact of agriculture on the groundwater chemistry. reduction in the content of inorganic components highly sensitive to changes in oxidation/reduction conditions in the aquifer has been observed (table 1). a possible explanation lies in the fact that when oxygen-rich water infiltrates water bearing layers rich in organic matter, the oxygen content is reduced (appelo & postma, 1994). in low-oxygen or an oxygen-free environment (reduction conditions), biochemical reduction of no3 and so4 2occurs. no3 reduces into no2 and nh3, while so4 2reduces into hsand h2s. the time analysis results show a significant positive trend for sodium and potassium within the entire catchment area (table 1, fig. 5). under some circumstances, when the groundwater gradients are high due to pumping of water from the wells, a vertical flow of groundwater is induced through clay and silty intercalations in the aquifer (hem, 1985), which may cause release of sodium and potassium ions from the crystalline screen, even if irreversible adsorption of potassium ions on the clay minerals is assumed. however, as an increase in sodium and potassium ions, and consequently in chloride ions, has been observed in the groundwater over the entire catchment area, it is more probable that leaking sewage, mineral and organic fertilizers and use of salt to prevent ice formation on roads cause positive trends in sodium, potassium and chlorides in the groundwater. similarities and correlations between the hydrochemical data from the observation well sites were checked using the data from two periods: june 2000, during low groundwater table, and october 2000, during the lowest groundwater table in 2000. data on chemical elements and compounds (table 2) are standardized as the mean value 0 and variance 1. the correlation matrices (table 3) show a sufficiently good correlation and no presence of singularity and multicolinearity between the observed variables. the factor analysis was performed on 10 variables. the analysis included nitrates, sulphates, chlorides and heavy metals as probable indicators of human impact. the results in tables 4 and 5 refer to the four most important factors that explain over 77% of variance for the hydrochemical data collected in june 2000 and 82% of variance for hydrochemical data from october 2000. the cluster analysis results for june 2000 are shown in fig. 6. the results show that the observation wells are grouped into four clusters. the mds analysis results (fig. 7) indicate that only an interrelationship between the observation wells from clusters one and three could be partly reproduced in the mds analysis. both analyses give similar results for the observation wells with minimum linkage distance. the cluster analysis results for october 2000 are shown in fig. 8. the results indicate grouping of the fig. 4 the piper diagram of the groundwater ionic composition in the mala mlaka well field catchment area. 93nakić, horvat & bačani: statistical indicators of groundwater geochemical characteristics... fig. 5 time trends of groundwater quality parameters in the mala mlaka well field catchment area: (a) geochemical trends; (b) trends as result of changing heavy metals detection limits (application of icp method since 1998). a b • • • • """'os • • • 10 v ... ... .... .. (u6whl h d 94 geologia croatica 58/1 parameter observ. well rs rs0 calc. χ2 critic. χ2 df trend parameter observ. well rs rs0 calc. χ2 critic. χ2 df trend 148 -0.60 -4.55 148 0.43 3.81 čp-23 -0.61 -4.58 čp-23 0.53 3.63 mm-311 -0.61 -6.66 mm-311 -0.12 -1.07 mm-319 -0.63 -7.1 mm-319 -0.07 -0.58 mm-32 0.01 0.03 mm-32 -0.54 -1.29 mm-322 -0.73 -6.49 mm-322 0.08 0.51 mm-323 -0.63 -7.11 mm-323 -0.06 -0.55 mm-324 -0.55 -5.53 mm-324 0.66 7.51 dissolved mm-330 -0.71 -5.77 mm-330 0.48 3.06 oxygen mm-331 -0.72 -6.16 72.1 30.14 19 ⇓ chlorides mm-331 -0.14 -0.83 31.58 27.58 17 ⇑ mm-332 -0.62 -6.61 mm-332 0.06 0.52 mm-333 -0.61 -3.67 mm-333 0.32 1.53 mm-80 -0.64 -4.33 mm-80 0.55 3.33 pzo-1 -0.43 -2.55 pzo-1 0.30 1.60 pzo-10 -0.60 -4.64 pzo-10 0.51 3.59 pzo-12 -0.60 -3.63 pzo-12 0.12 0.54 pzo-14 -0.54 -3.94 pzo-14 0.48 3.26 pzo-2 -0.50 -3.00 pzo-2 0.45 2.55 pzo-6 -0.25 -0.89 pzo-6 0.39 1.33 pzo-8 -0.78 -5.93 pzo-8 -0.56 -2.95 148 -0.67 -7.08 148 -0.83 -12.23 čp-23 -0.41 -2.59 čp-23 -0.69 -5.74 mm-311 -0.62 -6.77 mm-311 -0.77 -10.52 mm-319 -0.90 -17.63 mm-319 -0.63 -7.16 mm-32 0.83 2.96 mm-32 -0.74 -2.68 mm-322 -0.75 -6.78 mm-322 -0.69 -5.93 mm-323 -0.90 -18.40 mm-323 -0.57 -6.13 mm-324 -0.70 -8.40 mm-324 -0.64 -7.20 mm-330 -0.51 -3.39 mm-330 -0.36 -2.34 nitrates mm-331 -0.51 -3.49 56.64 27.58 17 ⇓ sulphates mm-331 -0.53 -3.77 126.85 30.14 19 ⇓ mm-332 -0.65 -7.13 mm-332 -0.73 -9.02 mm-333 -0.57 -3.14 mm-333 -0.86 -8.24 mm-80 -0.66 -4.41 mm-80 -0.98 -26.65 pzo-1 -0.14 -0.71 pzo-1 -0.64 -4.39 pzo-10 -0.41 -2.70 pzo-10 -0.80 -8.09 pzo-12 -0.53 -2.88 pzo-12 -0.85 -7.81 pzo-14 -0.56 -4.00 pzo-14 -0.69 -5.83 pzo-2 -0.37 -1.97 pzo-2 -0.79 -6.68 pzo-6 -0.10 -0.31 pzo-6 -0.68 -3.20 pzo-8 -0.81 -6.08 pzo-8 -0.91 -10.38 148 0.10 0.81 148 0.65 6.76 čp-23 0.41 2.59 čp-23 0.65 4.94 mm-311 0.54 5.52 mm-311 0.64 7.22 mm-319 0.19 1.66 mm-319 0.51 5.08 mm-32 0.49 1.13 mm-32 0.83 2.96 mm-322 0.47 3.18 mm-322 0.62 4.77 mm-323 0.42 3.97 mm-323 0.67 7.79 mm-324 0.31 2.78 mm-324 0.51 5.10 dissolved mm-330 0.27 1.56 mm-330 0.70 5.47 carbon mm-331 0.24 1.44 24.73 27.58 17 0 potassium mm-331 0.60 4.40 64.97 27.58 17 ⇑ dioxide mm-332 -0.05 -0.44 mm-332 0.64 7.00 mm-333 0.00 0.00 mm-333 0.45 2.31 mm-80 0.39 2.14 mm-80 0.78 6.33 pzo-1 0.08 0.39 pzo-1 0.37 2.01 pzo-10 0.12 0.76 pzo-10 0.57 4.16 pzo-12 0.25 1.18 pzo-12 0.59 3.36 pzo-14 0.05 0.29 pzo-14 0.35 2.24 pzo-2 -0.22 -1.12 pzo-2 0.36 1.99 pzo-6 -0.14 -0.45 pzo-6 0.55 2.06 pzo-8 -0.55 -2.94 pzo-8 0.62 3.55 148 0.31 2.62 148 -0.04 -0.33 čp-23 0.67 5.32 čp-23 -0.09 -0.54 mm-311 0.43 4.08 mm-311 -0.12 -1.04 mm-319 0.43 4.11 mm-319 -0.13 -1.11 mm-32 0.37 0.80 mm-32 0.68 1.84 mm-322 0.42 2.80 mm-322 -0.06 -0.36 mm-323 0.47 4.61 mm-323 -0.25 -2.19 mm-324 0.30 2.65 mm-324 -0.31 -2.81 mm-330 0.44 2.75 mm-330 0.24 1.42 sodium mm-331 0.29 1.80 37.05 27.58 17 ⇑ iron mm-331 0.30 1.86 19.41 27.58 17 0 mm-332 0.18 1.49 mm-332 -0.14 -1.15 mm-333 0.64 3.81 mm-333 -0.40 -1.98 mm-80 0.70 4.91 mm-80 -0.07 -0.37 pzo-1 0.11 0.58 pzo-1 -0.15 -0.75 pzo-10 0.31 1.94 pzo-10 0.038 0.23 pzo-12 0.28 1.33 pzo-12 -0.56 -3.09 pzo-14 0.29 1.79 pzo-14 -0.15 -0.91 pzo-2 0.30 1.62 pzo-2 -0.65 -4.33 pzo-6 0.67 2.82 pzo-6 0.05 0.15 pzo-8 0.25 1.15 pzo-8 -0.32 -1.53 table 1 – continued on the next page. 95nakić, horvat & bačani: statistical indicators of groundwater geochemical characteristics... parameter observ. well rs rs0 calc. χ2 critic. χ2 df trend 148 0.45 3.96 čp-23 0.56 3.91 mm-311 0.60 6.53 mm-319 0.49 4.91 mm-32 0.77 2.38 mm-322 0.57 4.21 mm-323 0.57 6.02 mm-324 0.28 2.46 mm-330 0.65 4.85 manganese mm-331 0.38 2.43 47.74 27.58 17 ⇑ mm-332 0.31 2.72 mm-333 0.34 1.66 mm-80 0.67 4.54 pzo-1 0.18 0.92 pzo-10 0.50 3.43 pzo-12 -0.01 -0.66 pzo-14 0.41 2.69 pzo-2 -0.19 -0.97 pzo-6 0.73 3.40 pzo-8 0.35 1.67 table 1 indicators of significant groundwater quality trends: spearmen correlation coefficient (rs), hypothetical null-distribution (rs0), results of χ2 test (p=0.05). observation wells in five clusters. unlike the june 2000 data, the mds analysis results (fig. 9) show a very high similarity compared to the cluster analysis. comparison of the cluster and mds analysis results for june and october 2000 shows an interrelationship between the observation wells in each of these two periods. pzo–1 and pzo–8 observation wells are grouped in cluster analysis. mds analysis shows that they depart in june, but there is some similarity so they might be grouped together. in october, the mds analysis results confirm grouping of these observation wells. figure 2 shows that these two sites are separated by a larger distance, but the observation well pzo–1 is located down no3 clso4 2 cr cu cd pb fe mn as mg n/l mg/l mg/l μg/l μg/l μg/l μg/l μg/l μg/l g/l mm310 4.9 12.9 23.6 0 1 0.1 3 0 0.1 0.1 mm311 5.4 12.2 19 0 1 0.2 0 0 0 0.2 mm319 6.9 23.4 27.4 0 0 0 5 0 0 0 mm32 6.6 10.8 28.1 0 1 0 2 0 0.1 0.1 mm320 6.2 32.9 26 2 1 0 5 0 0 0.1 mm321 6.9 28.6 39.6 1 1 0 8 0 0 0.2 mm323 6.2 19.2 27.5 0 2 0.1 7 7.6 0.6 0.1 a mm324 3.2 22.1 37.1 0 1 0 5 0 0 0.3 mm325 7 18.3 31.6 0 0 0 9 1.6 0.2 0.2 mm332 4.2 22.9 52.5 1 1 0 9 2.7 0.4 0.1 mm333 7.8 40.9 30.4 1 3 0 0 0 0.1 0.2 pzo1 2.1 14.1 24.1 1 2 0 7 7 0.5 0.1 pzo12 5.6 37.1 29.8 0 2 0.5 3 0 0.1 0.1 pzo2 1.9 14 24.9 0 1 0.4 4 0 0.2 0.2 pzo8 2.2 12.3 19.8 0 3 0 9 14.7 0.3 0.3 mm310 4.6 13.6 23.1 0 0 0.1 3 0 0.1 0.1 mm311 5.1 12.4 19.6 0 0 0.1 0 0 0.2 0 mm319 7.1 23.7 27.2 0 0 0.4 13 30.6 0.3 0.4 mm32 7.2 11.9 26.7 0 0 0 6 4.9 0.2 1.4 mm320 5.6 34.4 24.5 3 2 0 5 0.5 0.2 0.9 mm321 6.6 28.9 36.4 0 3 0 1 13.8 1 0.8 mm323 6.1 21.8 28 2 0 0.1 8 3.2 0.2 0.2 b mm324 2.6 21.3 33.3 0 3 0 0 27.1 1.8 0.9 mm325 5.1 18.4 29.1 6 3 0 3 4.7 0.1 1 mm332 4 28.9 51.2 0 3 0 9 38.3 1.2 1.1 mm333 8.5 42 32.5 0 3 0.3 1 0 0.1 0.3 pzo1 1.2 12.1 21.5 1 2 0 1 2.5 0.2 0.4 pzo12 5.9 37.2 30.4 1 2 0.6 4 0.4 0 0.4 pzo2 1.1 13.9 23.8 0 3 0 5 0 0 0.5 pzo8 2.1 13.4 19.9 0 2 0.3 1 1.7 0.1 0.6 table 2 chemical analysis data for (a) june 2000, and (b) october 2000. 96 geologia croatica 58/1 variable 1 2 3 4 5 6 7 8 9 10 1 no3 1.00 2 cl 0.50 1.00 3 so4 0.15 0.36 1.00 4 cr 0.15 0.51 0.29 1.00 5 cu -0.23 0.23 -0.23 0.13 1.00 a 6 cd -0.21 0.09 -0.24 -0.37 0.08 1.00 7 pb -0.27 -0.16 0.40 0.13 -0.11 -0.36 1.00 8 fe -0.47 -0.35 -0.25 -0.10 0.58 -0.22 0.56 1.00 9 mn -0.37 -0.29 0.06 -0.02 0.38 -0.06 0.50 0.69 1.00 10 as -0.38 -0.01 -0.02 -0.10 0.32 0.00 0.17 0.28 -0.09 1.00 variable 1 2 3 4 5 6 7 8 9 10 1 no3 1.00 2 cl 0.55 1.00 3 so4 0.22 0.53 1.00 4 cr 0.07 0.07 -0.08 1.00 b 5 cu -0.31 0.41 0.48 0.17 1.00 6 cd 0.33 0.42 -0.11 -0.19 -0.17 1.00 7 pb 0.28 0.12 0.28 0.02 -0.36 0.17 1.00 8 fe 0.01 0.15 0.72 -0.24 0.17 -0.09 0.48 1.00 9 mn -0.14 0.13 0.65 -0.25 0.38 -0.36 -0.08 0.77 1.00 10 as -0.00 -0.00 0.43 0.17 0.35 -0.42 0.09 0.37 0.40 1.00 table 3 correlation matrix of 10 variables computed from chemical analysis data for (a) june 2000, and (b) october 2000. factors eigenvalues % total cumulative cumulative variance eigenvalues % a 1 2.99 29.86 2.99 29.86 2 2.09 20.87 5.07 50.73 3 1.56 15.58 6.63 66.31 4 1.11 11.07 7.74 77.37 b 1 3.18 31.82 3.18 31.82 2 2.19 21.90 5.37 53.72 3 1.54 15.43 6.92 69.15 4 1.28 12.81 8.20 81.96 table 4 eigenvalues derived by factor analysis, percentages of total variance, cumulative eigenvalues and cumulative percentages explained by factors: (a) june 2000, (b) october 2000. stream from the group of the pollution sources which might affect the water chemistry at this site. it may be assumed that similarity in the groundwater chemistry at sites pzo–1 and pzo–8 is probably a consequence of local hydrodynamic and hydrogeochemical conditions in the shallow water bearing layer. observation wells mm–321, mm–324 and mm–332 are grouped in cluster analysis during june and october 2000, and the mds analysis results show their grouping in october 2000. grouping of these observation wells, which are set at small distances in the second protection zone of the mala mlaka well field (fig. 2), points to the impact of numerous pollution sources (illegal dump sites and gravel pits) located downstream from the observation wells at the sites under consideration. observation wells pzo–12 and mm–333 are grouped in cluster analysis for june and october 2000. the mds analysis results for june 2000 are separated, but there is a certain similarity so they might be grouped together. in october, the mds analysis results confirmed grouping of these observation wells. the distance between these observation wells is small along the sava–odra canal (fig. 2). it might be presumed that similarity of the groundwater chemistry in the observation wells pzo–12 and mm–333 is probably a consequence of local hydrodynamic and hydrogeochemical conditions in the shallow aquifer. observation wells mm–310, mm–311 and pzo–2 are grouped in both analyses, for june and october 2000. the distance between the observation wells mm– 310 and mm–311 is small, and they are located downstream from the illegal gravel pits and dump sites (fig. 2). the results of cluster analysis for october 2000 show the extraordinarily small linkage distance of these sites. there is a high probability that the illegal gravel pits and dump sites will have considerable impact on these observation wells. observation well pzo–2 is the largest distance from the dump sites and gravel pits, but upstream from this site, a larger group of pollution sources is recorded so the observation well is probably exposed to their impact. observation wells mm–32 and mm–319 are grouped in both analyses, in june and october 2000. the distance between these observation wells is larger, and they are located near the first protection zone: mm–32 to the east and mm–319 to the west from the first protection 97nakić, horvat & bačani: statistical indicators of groundwater geochemical characteristics... no3 cl so4 cr cu june 2000 0.68 0.87 0.69 0.66 0.93 cd pb fe mn as 0.49 0.84 0.91 0.78 0.87 a no3 cl so4 cr cu october 2000 0.70 0.93 0.88 0.81 0.88 cd pb fe mn as 0.75 0.81 0.91 0.85 0.67 factor factor factor factor 1 2 3 4 june oct. june oct. june oct. june oct. 2000 2000 2000 2000 2000 2000 2000 2000 no4 -0.41 -0.03 0.02 0.72 0.44 -0.41 -0.57 0.12 cl -0.25 0.24 -0.02 0.91 0.90 0.21 0.01 0.06 so4 -0.27 0.86 0.73 0.36 0.29 0.05 0.08 0.12 cr 0.07 -0.25 0.36 0.10 0.72 0.04 -0.11 0.86 b cu 0.70 0.41 -0.39 0.16 0.46 0.78 0.29 0.27 cd -0.16 -0.28 -0.64 0.66 -0.13 -0.12 0.19 -0.46 pb 0.38 0.27 0.80 0.21 -0.17 -0.83 0.19 0.08 fe 0.90 0.91 0.12 0.01 -0.17 -0.26 0.23 -0.12 mn 0.83 0.88 0.23 -0.15 -0.16 0.22 -0.09 -0.12 as 0.04 0.56 0.01 -0.17 0.04 0.00 0.93 0.57 table 5 communalities from 4 derived factors – (a) factor loadings, (b) factor rotation of four factors through varimax method (marked factor loadings >0.7; june 2000, october 2000). fig. 6 results of cluster analysis shown by a dendogram of june 2000 data. fig. 7 results of multidimensional scaling analysis shown by the two most important dimensions (june 2000). zone border (fig. 2). upstream from mm–32 is a site that accommodates workshops and upstream from mm– 319 an illegal gravel pit filled with waste is located. 6. conclusion most of the activities currently carried out in order to protect the groundwater of the zagreb aquifer system have been focused on the areas immediately adjacent to the well fields or within the well field protection zones. the fact that the well field is only a point where groundwater is tapped for water supply was neglected, and the entire catchment area should be controlled. efficient protection of the groundwater in the well fields is only possible if the catchment area boundaries were determined from the information on the underground hydrodynamic conditions, and geological and hydrogeological relationships within the entire system. in line with this approach, catchment areas were determined for five zagreb well fields (zapruđe, mala mlaka, velika gorica, sašnjak and petruševec) within the croatian groundwater recording and management project. 98 geologia croatica 58/1 fig. 8 results of cluster analysis shown by a dendogram of october 2000 data. fig. 9 results of multidimensional scaling analysis shown by the two most important dimensions (october 2000). the results of the numerical simulation were used as background for further research into groundwater quality and protection. the pollution sources were recorded within the catchment area boundaries, and the chemical analysis data were collected and systematically presented for the period 1994–2000. standard methods were used for determination of the hydrogeochemical facies, and it was found that the groundwater in the mala mlaka well field catchment area belongs to a ca–mg–hco3 type of water. the analysis of time trends has revealed geochemical processes in the groundwater of the quaternary aquifer, and grouping of the observation wells based on the groundwater chemistry in individual sites confirmed existence of human impact on the groundwater quality. the following was detected: – relatively high concentrations of sodium, potassium, nitrates and sulphates in the groundwater confirm the impact of agricultural activities on the groundwater chemistry. positive trends of sodium, potassium and chlorides are a consequence of the application of mineral and organic fertilizers on agricultural land, leaking sewage and use of salt to prevent ice formation on roads during the winter. – reduction in the content of inorganic components, nitrates and sulphates, which are sensitive to changes in oxidation/reduction conditions in the water bearing layer is caused by infiltration of oxygen-rich water into the aquifers rich in organic matter, which results in reduction of oxygen due to its consumption for organic matter oxidation. in environments, which are often reducing, nitrate contents decrease by their reduction into nitrites and, depending on the oxygen content, into ammonium. the situation is similar with sulphates which are reduced to sulphite and finally into hydrogen sulphide where oxygen levels are reduced. both transformation processes are caused by microbial activities. – registered pollution sources in the area, illegal dump sites in particular, caused degradation in the groundwater quality in some sites. this impact is traceable even several hundred metres from the registered pollution sources. 7. references appelo, c.a.j. & postma, d. (1994): geochemistry, groundwater and pollution.– balkema, rotterdam, 536 p. bačani, a. & šparica, m. (2001): geology of the zagreb aquifer system.– 9th international congress of the geological society of greece, proceedings, xxxiv/5, 1973– 1979, athens. borčić, d., capar, a., čakarun, i., kostović, k., miletić, p. & tufekčić, d. (1968): prilog daljnjem poznavanju aluvijalnog vodonosnog horizonta na širem području zagreba [contribution to the study of the alluvial aquifer in the area of zagreb – in croatian].– geol. vjesnik, 21, 303–309. brown, c.e. (1998): applied multivariate statistics in geohydrology and related sciences.– springer-verlag, berlin, 248 p. čakarun, i., mraz, v., babić, ž., mutić, r., sokač, a. & franić, d. (1987): geološke i hidrogeološke specifičnosti vodonosnog kompleksa prisavske ravnice na dionici granica sr slovenije–rugvica [geological and hydrogeological characteristics of the quarternary waterbearing complex of the river sava plain (on the section from the boundary with r. slovenia to the rugvica village) – in croatian].– geol. vjesnik, 40, 273–289. 99nakić, horvat & bačani: statistical indicators of groundwater geochemical characteristics... frapporti, g., linnartz, l.a.m. & vriend, s.p. (1991): spearmen-a dbase program for computation and testing of spearman rank correlation coefficient distributions.– computer & geosciences, 17/4, 569–589. frapporti, g., hoogendoorn, j.h. & vriend, s.p. (1994): detailed hydrochemical studies as a useful extension of national ground water monitoring networks.– in: frapporti, g. (ed.): geochemical and statistical interpretation of the dutch national ground water quality monitoring network. universiteit utrecht, den haag, 119 p. hem, j.d. (1985): study and interpretation of the chemical characteristics of natural water.– 3rd edition, u.s. geological survey water supply paper 2254, 263 p. jones, a.t. (2001): using flowpaths and vectors fields in object-based modeling.– computer & geosciences, 27, 133–138. kendall, m.g. & stuart, a. (1961): the advanced theory of statistics, 2.– charles griffin and co. ltd, london, 509 p. statsoft, inc. (1995): statistica for windows (vol. 3), statistics 2.– 2nd edition, statsoft, inc., tulsa, 3001–3781. suk, h. & kang-kun, l. (1999): characterization of a groundwater hydrochemical system through multivariate analysis: clustering into groundwater zones.– ground water, 37/3, 358–366. ward, j. h. (1963): hierarchical grouping to optimize an objective function. – j. of the americ. statist. association, 58, 301, 236–244. manuscript received july 2, 2003. revised manuscript accepted january 19, 2005. 100 geologia croatica 58/1 04 diamantopoulos.indd 1. introduction geological evidence in the hellenic orogenic belt of eastern mediterranean confirms complex neogene– quaternary tectonic processes, both in the orogenic front of the central and south aegean, and in the backarc domain of the north aegean and western macedonia (stewart & hancock, 1991; piper & perissoratis, 2003; kreemer et al., 2004; diamantopoulos, 2004; ocakoglou et al., 2005). these observations make evident the importance of heterogenous strain, including co-existence of strike-slip, rotational and ductile structures. since deformation and strain outline three-dimensional quantities, structural heterogeneity from the lithospheric-scale to the grainscale of observation mark an essential constituent of strain (jones et al., 2005; de paola et al., 2005). this work analyzes the plio–quaternary structures and the deformation style in the ptolemais basin of plio–quaternary geometry and kinematics of ptolemais basin (northern greece): implications for the intra-plate tectonics in western macedonia anastasios diamantopoulos western macedonia in northern greece. new structural data, observed in the ptolemais basin are presented in order to elucidate the principal deformation styles and mechanisms in this area (fig. 1). distribution of deformational structures, the geometry and kinematics of deformation, and a new kinematic model for the ptolemais basin are also addressed. finally, an integrated evaluation of new data and their implications allows a new improved comprehension of intra-plate tectonics of western macedonia. 1.1. previous studies and target of this work previous studies of the ptolemais basin by pavlides (1985), doutsos & koukouvelas (1998), mountrakis et al. (1999), and goldsworthy & jackson (2000) provided an insight into the importance of active faults and their role in the geomorphology and seismology of this basin. structural data presented in these papers were mainly concerned with the geometry and kinematic characteristics of the observed fault sets. according to pavlides (1985) and mountrakis et al. (1999), multiple tectonic phases during miocene–quaternary times were recognized, each characterized by compressional or extensional structures. new structural analysis of the ptolemais basin in western macedonia presented in this paper, allows revision of previous assumptions on the geometry, kinematics and the tectonic evolution of this part of northern greece (fig. 1). this structural synthesis is based on data obtained by field analysis, drilling and geophysical investigations, which document the main structural pattern within plio–quaternary sediments, the sub-surface geometry of the ptolemais basin fill and also the re-activation of the pre-miocene structures by plio–quaternary tectonics. the study area is an open-pit lignite mine exploited by the public power corporation of greece (ppc). 2. geology of western macedonia geological data, geophysical studies and gps measurements in western macedonia denote on-going tectonic geologia croatica 59/1 85–96 8 figs. zagreb 2006 key words: progressive shear strain, intra-plate tectonics, ptolemais basin, western macedonia, northern greece. national technical university of athens, department of mining, metallurgical & engineering geology, section of geosciences, 9 herron polytechniou street, gr-15780, zografou, athens, greece; e-mail: diamantopoulos@metal.ntua.gr abstract an integrated structural study of the ptolemais basin of northern greece allows assessment of deformation processes and their implication in the pliocene–quaternary structural evolution of this part of western macedonia. normal and reverse faults within plio–quaternary sediments, ne–sw striking anticlines in both plio–quaternary sediments and pre-tertiary basement-units, torsions and deformation partitioning, highlight the particular characteristics of intra-plate deformation. field investigations and drilling data infer the conclusion that intra-plate processes were governed by progressive shear strain during the plio–quaternary. a new kinematic model for the development of the ptolemais basin is proposed, showing the importance of progressive shear strain. 86 geologia croatica 59/1 activity (mountrakis et al., 1999; fountoulis et al., 2002; drakatos et al., 2005; burchfiel et al., 2005). here, several tectonic basins of continental origin developed during miocene–quaternary times (the florina, ptolemais, kozani–servia, almopia basins – fig. 1). the presence of plio–quaternary volcanism in the almopia basin (vougioukalakis et al., 2004 and reference there in), also indicates re-arrangement of the lithospheric material. the physiography of northwestern greece is characterized by the two elevated domains of pelagonian and pindic cordillera as well as by the two subsided domains of the mesohellenic and axios basins (fig. 1). the latter are interpreted as tertiary (aubouin, 1965) piggy-back basins with thick sedimentary accumulations. 3. geology of the ptolemais basin sedimentary fill of the ptolemais basin includes terrestrial and lacustrine sediments of miocene up to pleistocene age, abundant in lignite reserves (koukouzas et al., 2000; kvacek et al., 2002). steenbrink (1998) studied distinctive sedimentary facies and concluded that the basin formation started during the tortonian. diamantopoulos & dimitrakopoulos (2004a) by synthesis of tectono–sedimentary data, recognized three distinctive lignite members of miocene, pliocene and pleistocene age, intercalated with clastic sediments. the same authors also recognized two major unconformities within the sedimentary basin succession, i.e. the first one at the base of the miocene, (between the first terrestrial sediments and the pre-terfig. 1 tectonic map of western macedonia. three distinctive domains (dotted black boxes) with compressional field structures are illustrated, see mountrakis (1983), fotis (2004) and diamantopoulos (2004). inset map: the hellenic orogenic arc in the eastern mediterranean, based on mariolakos et al. (2004) and diamantopoulos (2004). legend for inset map: aep – aegean plate; afp – african plate; apmc – apulia micro-continent; cfz – cephalonia fault zone; naf – north anatolia fault; afz – axios fault zone; strmz – strymon fault zone; mnr – morpho–neotectonic region; sa – study area. 87diamantopoulos: plio–quaternary geometry and kinematics of ptolemais basin... tiary basement units), and the second one between the pleistocene strata and the pliocene sediments. arrangement and geometry of lignite layers of the ptolemais basin indicate a westward migration from the eastern marginal domain (vermion mountain) toward the western marginal domain (askion and vernon mountains), (diamantopoulos & dimitrakopoulos, 2004a). pre-tertiary basement rocks of the ptolemais basin can be subdivided into four distinctive tectonic units, (fig. 2b). from the lowermost to the highest unit, they are: (i) pre-alpine pelagonian basement, separated into schist sub-unit, the gneiss sub-unit, the granitoid mylonites and the granites (brunn, 1956; mountrakis 1983; diamantopoulos, 2005), (ii) almopia unit, with triassic–lower jurassic marbles and metafig. 2 (a) digital elevation model of western macedonia. photos of figs. 4 and 5 are depicted. (b) simplified tectonic map of the southern part of the ptolemais basin. inset map shows the spatial distribution of the analyzed drillings in three domains i, ii and iii of fig. 3. the location of the geological sections a–b–c of fig. 7 is also illustrated. a b 88 geologia croatica 59/1 sediments of late jurassic age (diamantopoulos, 2005), (iii) ultramafic–mafic unit of mesozoic age, and (iv) cretaceous unit, with platform limestones and maastrichtian flysch (mercier, 1968). steep and low-angle shear zones, formed in brittle–ductile conditions, separate distinctive tectonic units. recent structural studies show that during the oligo–miocene, a strong orogen-perpendicular stretching re-arranged the geometry of the pre-tertiary sequences (mountrakis, 2004; diamantopoulos, 2005). the nw–se strike of the ptolemais basin is controlled by pre-existing shear zones in pre-tertiary basement units, which accommodated oligocene stretching of the internal hellenides (diamantopoulos, 2005). these inherited structures correspond to several shear zones between pre-tertiary basement sequences. 3.1. morphotectonic units of the ptolemais basin the morphotectonic structure of the ptolemais basin comprises several fault-bounded blocks of different order. based on drilling and geophysical data, combined with a study of sub-surface and surface morphology, the following morphotectonic sub-units can be distinguished (diamantopoulos & dimitrakopoulos, 2004a, b; fig. 2): a) ne–sw trending vegoritis–ptolemais sub-basin, characterized by ne–sw orientated normal faults; b) ne–sw trending bordo horst; c) ne–sw trending komanos horst, which divides the vegoritis–ptolemais and ptolemais–kozani subbasins; d) nw–se ptolemais–kozani sub-basin, with a rhomblike geometry. the bordo and komanos horsts represent pre-existing structures, which were re-activated during plio– quaternary times. a significant difference in deformation style between the vegoritis–ptolemais and ptolemais–kozani sub-basins is indicated by their different strike and internal morphology, and by the greater depth and width of the vegoritis–ptolemais sub-basin. they also show a great difference in lithostratigraphic development and sedimentary evolution, which makes stratigraphic correlation of plio–quaternary strata between these sub-basins difficult (diamantopolous & dimitrakolopous, 2004a). 3.2. quantitative and qualitative analysis of borehole data borehole data, which include 720 boreholes that penetrated the plio–quaternary basin fill and 50 boreholes that reached the pre-tertiary basement have been taken into account, and are distributed in 3 domains (fig. 2b). the thickness of the pliocene lignite sequence and also the thickness of the plio–quaternary sediments (the overburden of the pliocene lignite sequence) have been quantitatively analyzed. diagrams a and b of fig. 3 shows the following thickness-variation pattern: a) thicknesses of the lignite sequences show a marked variation throughout the ptolemais basin. a local increase in thickness of more than 100 m indicates that sub-surface reverse faulting is very probable. field data, which are described below, support this presumption. b) the thickness of the plio–quaternary sediments also shows variation with respect to location within the basin. again, local thickness increase could possibly indicate subsurface reverse faulting. the above described data indicate that strong synsedimentary tectonics took place during sedimentation of the lignite and during deposition of the overlying quaternary sediments. field studies in all mines of the ppc confirm this aspect. however, the main thickness variations of the analyzed strata were determined within the central part of the ptolemais basin, i.e. in domain ii in fig. 3, where the komanos tectonic horst is located. 3.3. tectonic structures within the sedimentary basin fill tectonic structures in plio–quaternary sediments of the ptolemais basin include brittle and brittle–ductile fig. 3 (a) quantitative thickness variation of the pliocene lignite sequences; (b) quantitative thickness variation of the plio–quaternary sediments (overburden cover of pliocene lignites). the spatial distribution of the domains i, ii and iii is depicted in the inset map of fig. 2. a b 89diamantopoulos: plio–quaternary geometry and kinematics of ptolemais basin... structures of both extensional and compressional origin. in all mines of the ppc (amyntaion mine, south field, kardia mine, major field, komanos mine, north field and mavropigi field) steep to low-angle reverse faults of both n–s and e–w strike have been observed (figs. 4a–c, e, 5c, 6a (iii)). these reverse faults form pop-up stacks and co-exist with normal faults of planar and listric geometry (figs. 4d, 5c–f). the confirmed presence of these faults throughout the ptolemais basin shows how common this structural pattern is. co-existing pop-up structures and normal faults directly indicate the problem of interpreting kinematics and the style of deformation. diamantopoulos (2004), showed that large sub-surface basement-faults in the western margin of the ptolemais–kozani sub-basin have influenced the thickness and lithofacies characteristics of the sedimentary fill by creating sw-ward tilted fault blocks around nw–se trending rotational axes (figs. 2b, 7). surface morphology in the western margin of the ptolemas–kozani sub-basin is controlled by the sub-surface morphology, which in turn is defined by an anticline structure in basement-units, as illustrated in the tectonic sketch of fig. 6b. thus, a coincidence between the subsurface fold geometry and the surface morphology is confirmed. furthermore, at the boundary between the ptolemais–kozani and vegoritis–ptolemais sub-basins, a ne–sw striking anticline is determined, as well as in the western marginal part, where both the plio–quaternary sediments and the basement-units are folded in a km-size anticline (fig. 6b). this anticline structure also continues basinwards (at the northern boundary of ptolemais–kozani sub-basin), where the top of the pliocene lignites appears at the surface. a cb ed fig. 4 (a) reverse faults in the kardia mine forming a pop-up structure; (b) successive reverse faults in the kardia mine; (c) reverse fault in the mavropigi lignite field, stereographic projection includes its geometric characteristics; (d) normal faults in south field; (e) reverse fault and secondary reverse displacements in south field. 90 geologia croatica 59/1 these anticlines were also directly observed in the field (fig. 5a, b). within the upper parts of the anticlines, several normal faults indicate extension, while the lower part is dominated by reverse faults and experienced compression (fig. 5). these structural data, in combination with anticline geometry sediments (see stereographic projection of fig. 5g) suggest the predominant operation of a tangential longitudinal strain mechafig. 5 (a) anticline structure in the pliocene lignite sequence; (b) schematic profile – the black numbered circles correspond to structures observed in the upper (extensional) and lower (compressional) parts of the ne–sw anticline; (c) pop-up structure with reverse and dextral strike-slip faults, two separated sets of striation systems are depicted in the sketch and in the stereographic projection; inset sketch show the three-dimensional view of this structure; (d) listric and domino-style normal faults; (e and f) normal faults of listric geometry; (g) stereographic projection (of lower hemisphere) of the bedding within the anticline; h) three evolutionary stages show the genesis of a tangential longitudinal fold. a b c e f g h d 91diamantopoulos: plio–quaternary geometry and kinematics of ptolemais basin... nism during anticline formation (bobillo-ares et al., 2000 and references therein). different stages in the formation of these fold-types are shown in fig. 5h. the quaternary ductile–brittle structures described are also documented in the metamorphic basementunits in the western margin of the ptolemais–kozani sub-basin. structural analysis of the pre-alpine pelagonian basement revealed that folds of both synand postmetamorphic origin gently plunge to the nw and se, probably due to a later superimposed folding around a ne–sw trending fold axis (fig. 6a, projection i). a similar pattern is also seen in the orientation of the main ln+1 stretching lineation of the pre-alpine pelagonian basement units (fig. 6a projection ii). in addition, the ne–sw striking anticlines in klippen of the triassic–jurassic marbles of eastern askion and the eastern vernon mountains, have also been determined by diamantopoulos (2005). thus, the spatial arrangement of alpine (pre-miocene) folds coincides with the plio–quaternary anticlines, revealing the re-working of the basement-sequences. a b fig. 6 (a) orientation data. legend: (i) contoured plot of fold axes of the pre-alpine pelagonian basement in the western margin of the ptolemais–kozani sub-basin. (ii) contoured plot of l-fabric elements of the pre-alpine pelagonian basement in the western margin of the ptolemais–kozani sub-basin. (iii) planes of reverse faults of plio–quaternary sediments in the mining units of the ppc. (b) 2d-representation of the tectonic structure of the western margin of the ptolemais–kozani sub-basin, based on more than 550 drillings data of the ppc (from diamantopoulos, 2004). 92 geologia croatica 59/1 3.4. kinematics of deformation plio–quaternary sedimentary fill of the ptolemais–kozani sub-basin represents a westward tilting sequence, where the eastern margin is uplifted relative to the western margin. this is clearly observed in geological sections a and b of fig. 7. a similar geometry is also seen further north in the vegoritis–ptolemais sub-basin, where the sedimentary fill is tilted towards the west–northwest (fig. 2b). this tilting is interpreted as a result of an approximately nw–se trending axis throughout the basin. analysis of the geometry of pliocene lignites shows internal rotations of lignite fault-bounded blocks (geological section c of fig. 7). throw variation patterns in recognised sub-surface faults within plio–quaternary sedimentary fill also indicate their role and control on the basin history (fig. 7d). involvement of quaternary sediments in this tilting and rotation reveals the very recent re-arrangement of the basin marginal domains. 4. deformational pattern the above patterns, including structures in both the sedimentary fill and its pre-tertiary basement-units, indicate the complexity of deformation. given this evidence, the following must be considered in a new interpretation of the structural evolution of the ptolemais basin: a) a westward tilting of the sedimentary fill in the ptolemais–kozani sub-basin and a west–northwestward tilting of the sedimentary fill in the vegoritis–ptolemais sub-basin; b) a rhomb-like morphology of the ptolemais–kozani sub-basin (diamantopoulos & dimitrakopoulos, 2004a); c) the left-lateral strike-slip fault in the western marginal domain (diamantopoulos, 2004); d) the co-existence of reverse and normal faults in all mines of the ppc; e) anticline structures with a ne–sw axis trend in the internal parts of the basin; f) the kinematics of the deformation of pliocene lignites in the boundary between the ptolemais–kozani and vegoritis–ptolemais sub-basins (diamantopoulos & dimitrakopoulos, 2004b); g) the deformation partitioning between the marginal zones of the basin (diamantopoulos, 2004); h) the thickness variation of the pliocene lignites and of the plio–quaternary sediments; i) the different stratigraphy and sub-surface morphology between the ptolemais–kozani and vegoritis– ptolemais sub-basins, making the stratigraphic correlations difficult (diamantopoulos & dimitrakopoulos, 2004a), and j) the quaternary ductile–brittle deformation of the basement-units in eastern askion and the eastern vernon mountains (diamantopoulos, 2005). the main characteristic of the post-orogenic evolution of western macedonia are: (i) the convergent velocity field of the upper crustal levels in an e–w direction, as deduced from gps data, (fountoulis et al., 2002), (ii) the heterogeneous structure of the upper crust levels due to intricate pre-miocene nappe-emplacements, as documented by geophysical and structural studies (drakatos et al., 2005; diamantopoulos 2005), (iii) the plio–quaternary thermo–mechanical disequilibrium of the crust, resulting in the formation of volcanic centres (vougioukalakis et al., 2004, and references therein). these allow the conclusion that intra-plate deformation of western macedonia is dominated by progressive shear strain, which is proposed in the deformation model of fig. 8, where the principal axes of extension and compression, transtension and transpression are controlled by progressive sinistral simple shear. the co-existence of all the above tectonic structures also reflects the inhomogeneous spatial distribution of stresses. 5. tectonic origin of ptolemais basin and intra-plate tectonics of western macedonia the proposed model of progressive shear strain, the sub-surface morphology of the ptolemais basin, as well as the heterogeneous sedimentary evolution between the sub-basins of the ptolemais basin, constitutes criteria for identifying the domination of strike-slip kinematics. alternatively, stretching of the upper crust that resulted in basin formation is thought to have taken place with contemporaneous strike-slip displacements and torsion. a remarkable point of this connotation is that the above data agree well with data obtained by analogue modeling of pull-apart basins (aydin & nur, 1982; rahe et al., 1998; sims et al., 1999; kim et al., 2004; waldron, 2005). it is also noteworthy that during and after the miocene, the investigated area represents a stable back-arc domain, without plate re-organizations in the geodynamic regime of northern greece. apart from a south– westwards migration of the orogenic front of the hellenides (le pichon et al., 2002; mountrakis, 2004), new plate re-organizations are not recognised. therefore, differentiation in the stress regime is not justified. this is reinforced by the fact that since the tortonian the stable north–western convergent motion between the african and european plates in the hellenic realm has been determined (mazzoli & helman, 93diamantopoulos: plio–quaternary geometry and kinematics of ptolemais basin... fig. 7 geological cross-sections, for location see fig. 2. more than 100 drillings have been analyzed in order to determine the geometry of the sedimentary fill. in the upper part of each section the kinematic pattern of the separated morphotectonic sub-units is shown. (a) geological section from east (right side) to west (left side) direction. a westward tilting of the sedimentary fill is apparent together with complex structural patterns in the western marginal domain. (b) geological section in an east (right side) to west (left side) direction. a westward tilting of the sedimentary fill is apparent together with complex structural patterns and torsions in the western marginal domain. (c) geological section in southeast (right side) to northwest (left side) direction. the arrangement of a mega-anticline structure, including rotated lignite fault-bounded blocks, is visible. v1 and v2 represent the sinking velocities of the lignite sequence toward the northwest and southeast, respectively. (d) false throws of the recognized faults. numbering in the horizontal axis of the diagram corresponds to the faults in the previous cross-sections. b c a d 94 geologia croatica 59/1 1994). however, the late miocene–early pliocene onset of activity of the north anatolian fault (bozkurt, 2001) notes the role of a deep structure, which resulted in marked differentiation of stress gradients in the upper crust. in this framework, isostatic compensation of the previously collapsed crust in the oligocene, and deformation induced by thermo–mechanic disequilibrium of the upper crust, would provide the major generators in the formation of the intra-plate basins in western macedonia. these suggest that the major palaeogeographic modifications have taken place during the plio–quaternary. in addition, although western macedonia is described as a seismically inactive area (papazachos, 2002), the above evidence is a record of on-going tectonic activity in the upper crust. thus, as fountoulis et al. (2002) concluded, creep deformation is assumed to be dominant. three major pieces of evidence also indicate the lateral transmission of intraplate stresses throughout western macedonia. the plio– quaternary re-arrangement of the marginal domains of the ptolemais basin, the observed heterogeneity in the sedimentary evolution of the basin and the quaternary volcanism over western macedonia corroborate the former consideration. 6. conclusions the above analysis suggests the following new conclusions: – quantitative drilling analysis and field studies suggest that strong syn-sedimentary deformation took place during the plio–quaternary in the sedimentary fill of the ptolemais basin. – several lines of evidence indicate structural heterogeneity within the ptolemais basin. normal and reverse faults, strike-slip faults, anticlines with a ne–sw axis direction and torsions co-exist within the sedimentary fill. – the previously formed pre-miocene structures have been affected by plio–quaternary deformation, and can be particularly observed in the western margin of the ptolemais–kozani sub-basin, where concordant geometry between the basement-units and the plio– quaternary sediments are well-documented. – progressive shear strain, affecting both the plio-quaternary sedimentary fill and the basement-units, is considered as dominant. this is compatible with the spatio–temporal evolution of western macedonia since miocene times. these suggest that the major fig. 8 proposed kinematic model for the ptolemais basin. it is suggested that progressive shear stain dominates during the evolution of the basin, producing variable fault patterns and torsions. the shadow-like feature within the sketch shows the geometry of the basin, presumably fitting to a kink-like structure. at the base of the sketch the geometrical evolution of the ptolemais basin is represented. 95diamantopoulos: plio–quaternary geometry and kinematics of ptolemais basin... palaeogeographic modifications have taken place within the plio–quaternary. – isostatic compensation of previously collapsed crust in the oligocene, and deformation induced by thermo–mechanic disequilibrium of the upper crust, would provide the principal reason for development of intra-plate basins in western macedonia. acknowledgements real thanks are expressed to two anonymous reviewers for the helpful corrections of the manuscript. additionally, dr dimitrios dimitrakopoulos is really thanked for numerous discussions and advice. 7. references aubouin, j. (1965): geosynclines.– developments in geotectonics, 1, 335 p., elsevier. aydin, a. & nur, a. (1982): evolution of pull-apart basins and their scale independence.– tectonics, 1/1, 91–105. bobillo-ares, n.c., bastida, f. & aller, j. (2000): on tangential longitudinal folding.– tectonophysics, 319, 53–68. bozkurt, e. (2001): neotectonics of turkey – a synthesis.– geodynamica acta, 14, 3–30. brunn, j.h. (1956): contribution a l’etude geologique du pinde septentrional et d’une partie de la macedonie occidentale (geology of the ophiolitic northern pindos and western macedonia).– annales geologique des pays helleniques, vii, 1–358. burchfiel, b.c., king, r.w., todosov, a., kotzev, v., durmurdzanov, n., serafimovski, t. & nurse, b. (2005): gps results for macedonia and its importance for the tectonics of the southern balkan extensional regime.– tectonophysics, 413, 239–248. de paola, n., holdsworth, r.e., mccaffrey, k.j.w. & barchi, m.r. (2005). partitioned transtension: an alternative to basin inversion models.– journal of structural geology, 24, 1–19. diamantopoulos, a. (2004): intra-plate deformation and sub-surface tectonic structure of the western borderline of ptolemais–kozani graben (northern greece): evidences for back-arc compressional tectonics in the hellenic orogenic arc.– 1st panhellenic congress of greek young geologists, university of athens, department of geosciences & environment, proceedings book, 39. diamantopoulos, a. (2005): semi-brittle asymmetric shear planes controlling the cenozoic kinematics of internal hellenides (northern greece): field evidences from askion and eastern vernon mountain ranges.– international earth sciences colloquium on the aegean regions, iesca 2005, october 4–7, 2005, abstracts book, 31, izmir–turkey. diamantopoulos, a. & dimitrakopoulos, d. (2004a): the morphology and the sub-surface structure of the pre-tertiary basement of ptolemais–kozani graben (nw macedonia, greece).– 7th panhellenic geographical congress of the geographical society of greece, mytilini island, i, 415–422. diamantopoulos, a. & dimitrakopoulos, d. (2004b): intra-plate tectonics in western macedonia (northern greece): quaternary macrofolds and deformational pattern of ptolemais–kozani graben.– international symposium on earth system science, istanbul, turkey, 589–597. doutsos, th. & koukouvelas, i. (1998): fractal analysis of normal faults in northwestern aegean area, greece.– journal of geodynamics, 26/2–4, 197–216. drakatos, g., voulgaris, n., pirli, m., melis, n. & karakostas, b. (2005): 3-d crustal velocity structure in northwestern greece.– pure and applied geophysics, 162, 37–51. fotis, s.g. (2004): engineering geological problems in regions of dams in aliakmon river.– unpublished phd thesis, national technical university of athens, 217 p. fountoulis, i., paradissis, d., veis, n. & tsagaroulias, b. (2002): recent movements of the upper crust due to creep deformation based on gps measurements in w. macedonia (nw greece).– 11th general assembly of the wegener project 2002, athens, 1–10, greece. goldsworthy, m. & jackson, j. (2000): active normal fault evolution in greece revealed by geomorphology and drainage patterns.– journal of the geological society, london, 157, 967–981. jones, r., holdsworth, r.e., mccaffrey, k.j.w., phillip, c. & tavarnelli, e. (2005): scale dependence, strain compatibility and heterogeneity of threedimensional deformation during mountain building: a discussion.– journal of structural geology, 27, 1190–1204. kim, y.-s., peacock, d. & sanderson, d. (2004): fault damage zones.– journal of structural geology, 26, 503–517. koukouzas, c., kotis, th., metaxas, a., ploumidis, m., varvarousis, g., dimitriou, d. & ioakim, ch., (2000): potential of lignite deposits and paleoclimatic evolution of ptolemais basin during the neogene–quaternary period.– geological society of greece, special publications, 9, 151–162. proceedings interim colloquim rcmns, patras, greece, may 1998. kreemer, c., chamot-rooke, n. & le pichon, x. (2004): constraints on the evolution and vertical coherency of deformation in the northern aegean from a comparison of geodetic, geologic and seismological data.– earth and planetary science letters, 225, 329–346. kvacek, z., velitzelos, d. & velitzelos, e. (2002): late miocene flora of vegora, macedonia, n. greece.– university of athens, 175 p. le pichon, x., lallemant s.j., chamot-rooke, n., lemeur, d. & pascal, g. (2002): the mediterranean ridge backstop and the hellenic nappes.– marine geology, 186, 111–125. mariolakos, i., zagorchev, i., fountoulis, i. & ivanov, m. (2004): neotectonic transect moesia–apu96 geologia croatica 59/1 lia.– field guidebook & greek appendix–b26, 32nd international geological congress, florence–italy, 20–28 august 2004, 72 & 25p. mazzoli, s. & helman, m. (1994): neogene patterns of relative plate motion for africa–europe: some implications for recent central mediterranean tectonics.– geol. rundsch., 83, 464–468. mercier, j.l. (1968): etude geologique des zones internes des hellenides en macedoine centrale (grece), contribution a l’etude du metamorphisme et de l’evolution magmatique des zones internes des hellenides (geological study of the internal zones of hellenides in central macedonia (greece). contribution to the study of metamorphic and magmatic evolution of the internal zones of hellenides).– annales geologique des pays helleniques, xx, 1–792. mountrakis, d. (1983): the geological structure of the north pelagonian zone and the geotectonic evolution of the internal hellenides.– unpubl. phd thesis, university of thessaloniki, 289 p. mountrakis, d. (2004): tertiary and quaternary tectonics in greece.– 5th international symposium on eastern mediterranean geology, thessaloniki, greece, 1, 134– 137. mountrakis, d., kilias, a., pavlides, s., vavliakis, e., tranos, m., zouros, n., spyropoulos, n., chatzipetros, n., karakostas, b., scordilis, m., kostopoulos, d., gountromichou, ch. & thomaidou, e. (1999): neotectonic map of greece, sheet kozani, scale 1/100.000.– e.p.r.o., university of thessaloniki, 97. ocakoglou, n., demirbag, e. & kuscu i. (2005): neotectonic structures in izmir gulf and surrounding regions (western turkey): evidences of strike-slip faulting with compression in the aegean extensional regime.– marine geology, 219, 155–171. papazachos, c.b. (2002): active crustal deformation fields of the aegean area inferred from seismicity and gps data.– 11th general assembly of the wegener project 2002, athens, greece. pavlides, s. (1985): neotectonic evolution of the florina–vegoritis–ptolemais basin (w. macedonia, greece).– unpubl. phd thesis, university of thessaloniki, 265 p. piper, d. & perissoratis, c. (2003): quaternary neotectonics of south aegean arc.– marine geology, 198, 259–288. rahe, b., ferrill, d.a. & morris, a.p. (1998): physical analogue modelling of pull-apart basin evolution.– tectonophysics, 285, 21–40. schreurs, g.s. & colleta, b. (2002): analogue modeling of continental transpression.– journal of virtual explorer, 6, 67–78. sims, d., ferrill, d.a. & stamatakos, j.a. (1999): role of a ductile decollement in the development of pullapart basins: experimental results and natural examples.– journal of structural geology, 21, 533–554. steenbrink, j. (1998): orbital signatures in lacustrine sediments. the late neogene intramontane florina–ptolemais–servia basin, northwestern greece.– geologica utraiectina, 205, 167 p. stewart, i.s. & hancock, l. (1991): scales of structural heterogeneity within neotectonic normal fault zones in the aegean region.– journal of structural geology, 13, 191–204. viola, g., odoune, f. & mancktelow, n.s. (2004): analogue modeling of reverse fault reactivation in strikeslip and transpressive regimes: application to the giudicarie fault system, italian eastern alps.– journal of structural geology, 26, 401–428. vougioukalakis, g.e., eleftheriadis, g., christophides, g., pavlides, s., fytikas, m. & villa, i. (2004): volcanological study of the almopias pliocene volcanic formations (n. greece).– 5th international symposium on eastern mediterranean geology, thessaloniki city, greece, 1, 1318–1321. waldron, j.w.f. (2005): extensional fault arrays in strikeslip and transtension.– journal of structural geology, 27, 23–34. manuscript received december 7, 2004. revised manuscript accepted june 9, 2006. geol. croat. 50/2 1125 . 126 1 zagreb 1997 zahvala profesora milana heraka (acknowledgement by professor milan herak) stovani i dragi prijatelji, osim zahvalnos ti , recenome se tesko moze nesto bitnije dodati. pa ipak, dopustite mi jos nekoliko rijeci, makar i liz cijenu djelomicnog ponavljanja. pri znajem da sam s ugodnim uzhudcnjcm pratio izlaganj a svojih licenika, kolega i prijate lja, koji su, veoma obzirno, kriticke primjedbe ostavili za drugu prigodu. a bilo bi razloga i za njih. jer, radi sc 0 djclat · nosti koja je ponekad zahtijevala relati vno brza dono­ scnjc zakljucaka. a. osim toga, valjalo je raditi na vise podrucja, jcr strucnjaka je bilo premalo. pa, usprkos komp leksnosti, sva bi se l a djelatnost mogja svesti na svega ir i slova, povezana u rijec "krs", u krsli sam $c rodio , u njemu sam obavio terenske gcoioske vjezbe i vee 1938., makar u malom , osjelio car spoznavanja novog. iz krsa potjecu fosilne alge kao i ostac i spi ljskog medvjeda. tamo su i akumulacijska jezcra elektrana. on mi jc bio izvorom nckih opcih geo­ loskih spoznaja. osobito u vczi s karaktcristicnim stru­ kturnim i hidrogcoloskim odnosima u oinaridima, sto mi jc omogucilo uspostavljanjc novih koncepcija 0 lim odnosima. a sve se moglo od igrati i drugacije da nije bilo nc­ kih prij clom nih trenutaka i sretnih zaokrcta kojc eu ukratko pol1 ovili. da me prof. marijan salopek, kao studenta biologijc nije. vee nakon prve god inc studija, poveo na vjezbc iz gco loskog kartiranja, sigurno ne bih bio postao geo lo­ gom. oa ni sam u becu kratko vrijcme baravia kad juli­ jusa pijc, tada vodeeeg svjetskog palcoalgologa, ne bih sc bavio ros ilnim algama, pa ne bi h niti usao u unesco·ov medunarodni projekt 0 trijasu. a prigodna bccka paleobioloski nas trojena preda­ vanja u okvirll koncepcija uglednog othenija abela, polaknllla sll me da se i sam kasnije okusam u paleobio­ loskom pristllpll proucavanju spiljskog medvjeda. ravnatclj tadasnjeg geolosko-paleontoloskog mu ­ zeja josi p poljak, zaljubljenik krsa, sarno me lisputno povco u podrucje planiranih akumulacija licankc i croati(ln academy of sciences and arts, ante kovaciea 5, hr1oooo zagreb, croatia. lokvarke u gorskom kotaru; kasnije je taj slucajni pos­ jet pridonio rjesavanju akumulacija, ali je i prcrastao u temcljno dugogodisnje istrazivanje strukturnih odnosa. u medu vre menu sc pojavila potrc ba pronalafenja analognih rjesenja na sircm prostoru dinarskoga krsa, sto je urodilo novim spoznajama 0 tcktogenetskoj klasi­ rikaciji krskih terena. krs mi je kasnijc omogucio daleka putovanja u kra­ jeve razlicitih podneblja, kultura i civ ilizacija, od stje· njaka i jamajke, preko kanarskih otoka i sredozemlja do perzije, uglavnom u okviru visegodisnjeg medllnaro­ dnog projekta ageneija fao i unesco koji sam imao cast voditi i tako suradivati s veoma istaknutim stru ­ cnjacima. bilo je, dakako inozemnih pulovanja i u orga­ nizaciji nasih projektnih ustanova. primjenjujuei tako teorij ske geo loske spoznaj e, za uzvrat sam stekao veoma vrijedne povratne informacije na temelju dubokog buscnja, bojenja krskih vodotoka i primjene gcofizickih metoda, sto su mogle osigurati sarno organizacije s bogatom matcrijalnom osnovom. sve se to odrazi lo ne sarno u te me lj nim istraziva­ njima nego i u nastavi, a utjecalo je i na koncepciju udzbenika. zato sam ponosan da upravo tadasnje gene­ rac ije nasih ucenika danas kompetentno nose glavni teret nase geologije na teorijskoj i prakticnoj osnovi. no, sve to ne bi bilo moguee bez razumijevanja i pomoci drugih. na prvom bih mjeslu spomenuo uskladene obitelj · skc odnose u kojima sam nasao nc samo potporu nego i izravnu graficku pomoe. a nije bi lo lako mimo pod­ nosit i stalne ispracaje i doceke, decenijim a se odricati zajednickog godisnjeg odmora i imati razumijevanja za neizazvane promjene raspolozenj a. l ednako su tako pozitivno djelovali kolegijalni od­ nosi u svim ustanovama u kojima sam radio. nc mogu zaboravit i koleg icu donalu dcvi de­ nedela, koja je na sve oko sebe prenosila istrazivacki zar i ijubav za geologiju. takoder ee mi u irajnom sjecanju os lati s istcma­ ticnost, istrazivacka upornost i spremnost za suradnju kolegice vande kochansky-devid6. this speech was presented at the scientific meeting dedicated to the 80th anniversary of the life of professor milan herak, held on march 5th, 1997 in zagreb 126 obilje in spiracija i poticaja nasao sam u vodenju brojnih diplom skih . magistarskih i doktorskih radova koji su rcdovito bili povodom izmjene misli l1a abo­ slranu korist. zato mi se medu 63 suautora raznih tek­ slova pridruzilo i 25 mojih llcenika, neki jos u njihova studentsko doba. svc me to obvezuje na iskrenu i duboku zahvalnost spomenutima, a i mnogima nespomcnutima. bez nji ­ hove suradnjc, pomoci i poticaja put bi mi bie mnogo tezi, a ucinak ograniceniji. uc.:010gl:l l.foalic a -:lull na kraju, zahvalan sam organi zalorima ovog sasla­ nka, za mcne punog emocija. jer su me barem na kratko vrijeme odvojili od svakodnevice, koja mi ncpovratno vise namece strucne rcminiscencije, li z po koju spozna­ jnu dopunu, nego neki novi iskorak u djelatnosti koja je obiljezila moju proslost. ujedno, zahvaljujern darovateljima spomen poklona kao i svima varna koji ste mi svojim udjejom i nazo­ cnoscu ucinili ovaj sastanak nezaboravnim. geol. croat. 49/2 345 346 1 fig. zag reb 1996 ahsiuic/ note structure of the adriatic dinaric platform along the secovlje postojna profile marijan pol.jak and igor riznar the adrialie dinaric pial form (gusic & jelas­ ka , 1993) re fers to a ca rbonate platform of the ex icf­ ili.d dinarides o f mesozoic (u pper triassic to cre ta­ ceous) and palaeogene (palaeocene to lower eocene) age. in its northwestern part , several palaeogeograph ic units can be d istingui shed. the first one occupies the nort he rn part o f (s tria lip to the skofije-dekani -kubc t area . here, a hiatus occurred in sedimentat ion from the upper cenomanian 10 ihe pa laeocene (yelic & yla­ hovle, 1994) . the area to the northeast, (hal belongs 10 the slovene kras, is characterized by an clll crs ion duri ng uppe r cam panian lime (jurkovsek cl ai. , 1996). in the area northeast from postojna , the emer­ s ian is lim itcdto the upper maastri ch tian (s ri bar , 1996). tccloni ca lly , the adriatic-dinaric ca rbonate plat­ form exh ibits different degrees of struc tural de forma­ tion. the least de form ed part is the all-shore and on­ shore islrian pial form (d urasek e l ai., 198 1) wil h a domi nant radial type of deformation. to the northeast the terrain of kras, in addition to the vipava va lley and • lju6u.o."~ ri g. 1 gcoiogicll i cross-sec ti on sccovljc-poslojlla. geo]ogic,d survey, oimiccva 14, 1000 ljubljana, slovenijil. i3rkini , is characterized by gentle fo lds ancl longituciinal normal to reverse fault s. the most cleformed pan is the high karst zone that lies northeast from postojna. there could be a supposed re lationsh ip between the palaeogeographic and st ruc tu ra l units . diltere nces in c rc taccous sed iment at ion may have been caused by synsedimenta ry norm al fa ulting a long reg ional faulls. these fau lts became reverse lis tric ones during eocene regional compression. the main tec tonic displaeemcnt probably took place along the base or carbonate rocks a t the depths or 6000-7000 m. at the surface the displace­ ment is absorbed mainly by foldin g, whi ch is most intensive in the contact zones between the afo remen­ tioned palaeogeographic units. th e mosl promincnt deformed zo ne is the south ­ western slope of cicarija. it has been gcncrall y inte r­ pre ted as a thru sted and imbrica ted struc t ure (ple­ n ica r e l al. . 1969; sikh': e l ai. , 1972). il oweve r, de lajieci investigat ions have shown that ih is area is built lip predominantl y o f va rious types of fo lds ihal are onl y slight ly displaced along reverse faults (fig. i). e fly~di (i:o<ene i pc lime~tones t p"loe"cent j i( lime$tones end dolem,tts (crctilcc'qijs i j limesl 011 6 end delcmites uljrossic i t mo. inly co.rhonote rocks (lipper trio.ssic 1 iolz-pz moinly cl<l. slie rocks (l<l.we, to middle t,,,,r.soc:. permi"n l , faults: obstrvm (in the surface .... ~ ,nterrtd ,,' depth 346 references durasek, n., frank, g., jenko, k. , kuzina, a., tonctc-gregl, r. (1981): prilog poznavanju naclno geoloskih odnosa u sjeverozapadnom dijelu jadranskog podmorja.jug. akad. znan. umj., ser. a, 8, 201-2 13, zagreb. gustc, t. & jelaska, v. (1993): upper cenoman­ ian -lower turonian sea-leve l rise and its conse­ quences on the adriatic-dinaric carbonate plat1'orl11.geol. rundscil. , 82, 676-686. jurkovsek, e. , toman, m., ogorelec, b., sriilar, l., drobne, k., pollak, m. & srib­ ar lj. (1996): formacijska geoloska karla juznega dela trzasko-komenske planote, 1:50 000 geologi­ cal map or the southern part or the trieste-komen plateau; cretaceous and paleogene carbonate rocks). lnstitut za geologijo, geotchniko in geofiziko, ljubljana, 143 p. geologia croatica 49/2 plenicar, m., polsak, a. & siki c, d. (1969): osnovna geoloska karla sfrj i: 100 000, lisi trs!.­ zvezni geoloski zavod, beograd. sikic, d., plenicar, m. & sparica, m. (1972): osnovna geoloska karla sfrj i: 100000, lisl l lirska bistrica.zvczni gcoloski zavod, beograd. sriilar, l. (1996): evolucija gornjokredne ladransko­ dinarskc karbonatne platforme v jugozapadnoj sloveniji.unpublished m.sc. thesis , university of zagreb, 89 p. velic, i. & vlahovic, i. (1994): foraminiferal assemblages in the cenomanian of the buzet-savu­ drija area (northwestern istria, croalia).gcol. croa!., 47/1, 23-43. 1. introduction the robinzon spring in the duboka ljuta valley near dubrovnik (fig. 1) is one of the important karst springs within the dubrovnik area, which is captured for the water supply of the town of cavtat and its surroundings. the spring is located on the regional tectonic contact where carbonate sediments are thrust over clastic flysch deposits, and where this structure is cut by a dextral tear fault known as the slivnički fault. the spring consists of several dispersed springs of similar yields which well upwards forming a small pond 10 m wide at an altitude of 0.7 m. this pond empties to the sea via a 50 m long channel. the spring discharge is variable, depending on hydrological conditions. usually, during dry periods of the year (mostly during summer), the amount of fresh water feeding the spring is reduced. as a result, the balance between the freshand seawater is disturbed, causing seawater to intrude into the aquifer. geologically, this condition is predisposed by the deeply weathered and eroded contact between the permeable and imperthe effect of the seawater intrusion on the robinzon coastal spring renato buljan1, tamara marković1 and zoran peh2 meable rocks in the zone around the spring’s location. water losses through the 16.6 km long hydrotechnical tunnel of the dubrovnik power plant near the spring (which connects the accumulation of trebinje with the dubrovnik power plant) used to increase the spring’s capacity during the droughts. however, repair works in the hydrotechnical tunnel (fig. 2) in 1998, prevented further losses causing the spring to return to its natural condition. the main goal of this study was to find out more information about the underground strata of the spring area using borehole measurement data, and preexisting knowledge of the dynamics of freshand seawater inputs during the summer period when great amounts of fresh water are required. 2. methods data concerning the tectonic/structural setting, main flow directions in the karst aquifer and depth of the eroded contact between permeable and impermeable rocks were compiled from aerial photographs of the study area and by hydrogeological mapping of the area around the spring (fig. 2). geophysical data can also contribute to the direct characterization of data by providing multi-dimensional and high resolution subsurface measurements in a minimally invasive manner (hubbard & rubin, 2000). thus shallow reflective seismics were used to detect the contact line between the permeable and impermeable rocks, and to determine the thickness of the rockfall and spring deposits within the spring zone. seismic results were used to determine locations for the four research boreholes surrounding the spring. these were located perpendicularly to the spring zone and aligned to the cross-section a–b in order to measure permeability. borehole r–1 was located in the zone of the deepest contact between dolomites and flysch, r–2 was located west of the pumping station, while boreholes r–3 and r–4 were situated on the rims of the spring zone. the area between the boreholes was investigated by geophysical seismic tomographic measurements (andrić, 20013). a pumping test was geologia croatica 59/2 139–147 5 figs. 2 tabs. zagreb 2006 key words: salt-water/freshwater relationship, coastal aquifer, karst, croatia. 1 croatian geological survey, department of hydrogeology and engineering geology, sachsova 2, hr-10000 zagreb, croatia; e-mail: tamara.markovic@hgi-cgs.hr 2 croatian geological survey, department of mineral resources, sachsova 2, hr-10000 zagreb, croatia. abstract the robinzon spring, located 70 m from the seacoast, is a freshwater, perennial spring with a yield ranging from the maximum 2 m3/s to the minimum 0.165 m3/s. the spring occurs at the contact between permeable carbonate rocks and impermeable flysch deposits. this contact is deeply weathered, eroded and submerged below sea level. such conditions emphasize the delicate relationship between the freshand seawater. the objective of the study was to shed more light on the hydrogeological setting of the spring’s underground recharge area by means of borehole measurements and preexisting knowledge about the dynamics of the freshand seawater acquired from similar cases. the spring’s underground area is divided into three zones: (i) zone of good water circulation (rockfall material and fractured dolomite), (ii) zone of poor water circulation (massive dolomites), and (iii) zone of ‘trapped’ water (contact between the dolomite and flysch deposits). 3 andrić, m. (2001): robinzon–duboka ljuta, seizmička tomografska mjerenja [robinzon–duboka ljuta tomographic measurements – in croatian].– unpublished report, archive of the civil engineering institute of croatia, zagreb, 30 p. 140 geologia croatica 59/2 also performed with station pumps working for 7.5 hours with the capacity of 260 l/s. during the pumping test electroconductivity (ec), temperature (t) and water level were measured every 5 m down the boreholes and in the pond. data describing the lithology and tectonic setting of the wider area of the spring were taken from the basic geological map, sheet dubrovnik (marković, 1966, 1971). however, data explaining the natural conditions of the robinzon spring before the power plant had been built were drawn out from the cadastral sheet of the duboka ljuta–robinzon spring (perger, 19604). chemical analyses of the spring water were collected from the department of public health of splitsko–dalmatinska county, and the ina department of fluid analysis and ecology. these were used to determine the water type and influence of the sea on the spring water composition. 3. morphological characteristics and geological setting the robinzon spring is located in the coastal region of southern dalmatia, approximately 2 km north of the town of cavtat. in the steep hinterland of the spring there is a coastal range of hills typically reaching elevations in excess of 400 m above the sea level. the hinterland is a carbonate plateau composed of carbonate rocks and studded with numerous ponors. the climate is typically mediterranean with mild, rainy autumns and winters, and dry, hot summers. the air temperatures seldom drop below 8°c during the winter, while the highest values rarely exceed 30°c during the summer. mean annual precipitation is approximately 1900 mm. the catchment area of the robinzon spring is formed of triassic, jurassic and cretaceous carbonate sedimentary rocks, eocene flysch deposits, and various types of quaternary sediments (fig. 2). the upper triassic dolomites, occasionally alternating with dolomitic limestone, prevail in the hinterland, reaching a thickness of approximately 300 m. the mesozoic carbonate rock formation is completed with jurassic and cretaceous limestones succeeding the upper triassic dolomites in normal sequence. flysch deposits, extended along the coastline, play a crucial role in forming the robinzon spring as these separate the permeable, freshwater saturated carbonate rocks from the sea. rare quaternary deposits can occur both in the sinkholes (terra rossa) and on the steep part of the seaward side of the coastal range, forming the rockfalls. anthropogenic deposits can be also found within the spring area. these were formed during the construction of a tunnel and several underground rooms for the nearby power plant. geological structures in the surveyed area extend mostly nnw–sse, or nw–se. the dip of the layers and fault planes suggest the predominant direction of movement of the thrusted subsurface structures (prelogović et al., 19945; buljan & prelogović, 1997; bulj­ an, 1999). the hinterland of the robinzon spring is traversed by a major thrust moving the regional dinaricum structural unit over the epiadriaticum unit (her0 1 2 3 4 5 km du br ov ni k ca vt at rob inzo n 306 412 452 iva nic a vla štic a 910 402 192 29 128 k u par i 628 625 758 152 701 181 n a d r i a t i c s e a 520 oš tra gla va 618 0 500 km c r o a t i a zagreb 0 50 100 km0 50 100 km location of the study area slo h bi h me fig. 1 location map of the robinzon spring. 4 perger, v. (1960): kartoteka izvora, duboka ljuta – izvorište robinzon [data about duboka ljuta – the robinzon spring – in croatian].– unpublished report, archive of the hrvatska elektroprivreda, dubrovnik, 80 p. 5 prelogović, e., buljan, r. & fritz, f. (1994): he ombla, strukturna istraživanja [ombla power plant, structural investigations – in croatian].– unpublished report, archive of the croatian geological survey, zagreb, 86 p. 141buljan, marković & peh: the effect of the seawater intrusion on the robinzon coastal spring ak, 1977, 1986, 1991). the dip of the plane of tectonic transport is approximately 30°, while the estimated horizontal movement is over 10 km (marković, 1971). carbonate deposits strike ne–sw with moderate (20– 50°) northwest dip, revealing a monocline placed behind the steep front of the thrust. major joint and fault systems in the surveyed area strike 105–295° and 25–205°. the hinterland is a heavily faulted terrain traversed by sub-vertical tear faults with predominantly strike-slip (horizontal) movements. fault planes are bent along the strike direction with varying strike and dip of the bent segments. the most important fault zone in the area is the zone of the slivnički fault (measured parameters: r136/72/62), with reverse dextral movement (fig. 2). this zone divides the major dinaricum structural unit into two structural blocks, which are further broken by smaller transverse faults into local tectonic structures. in its upper part, the zone of the slivnički fault represents a linear divide between the robinzon and ombla catchments (milanović, 1977). generally, the thrust is cut almost perpendicularly by a number of transverse faults of different size and importance, which occurred as a result of the long horizontal movement during the faulting and thrusting of the carbonate rocks over the younger flysch deposits. some segments of the thrust are also reduced and eroded along the contact due to the strike slip of individual blocks. faults with planes dipping r10/74 and r87/82 are dominant in the immediate vicinity of the robinzon spring (fig. 2). the area between the spring and its hinterland is tectonically destroyed and partially eroded. it is dominated by the steeply-dipping faults: r194/84, r310/78/150 (normal dextral), and r280/80, r352/76/50 (reverse dextral). a number of smaller faults of secondary importance also occur in the vicin. . . . . . i i i i i i i i i i i i ii i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i ? ? 544 510 515 518 538 585 576 600 200 100 300 400 500 50 0 j1 j1 j1 j1 j1 j2 j2 j2 j2 t3 t3 t3 e2,3 2,3 e2,3 q de q s na d r i a t i c s e a0 500 m ro bi nz on e2,3 i i i a b legend: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 a b e fig. 2 simplified hydrogeological map of the study area. legend: 1 – permeable carbonate rocks; 2 – poorly permeable carbonate rocks; 3 – impermeable clastic rocks; 4 – permeable clastic rocks; 5 – geological boundary; 6 – chronostratigraphic unit; 7 – thrust fault; 8 – the slivnički fault; 9 – normal fault; 10 – tear faults; 11 – the robinzon spring; 12 – the dubrovnik power plant; 13 – caves; 14 – hydrogeological cross-section. 142 geologia croatica 59/2 ity of the spring. the immediate proximity of the spring location is characterized by a narrow zone of rockfall material formed at the foothill of the steep thrust fault scarp (fig. 2). the thickness of the rockfall material is up to 20 m in places. 4. hydrogeological features a number of issues relevant to the interpretation of hydrogeological relationships in this study must be fully understood prior to assessing the effects of seawater intrusion on the coastal spring. these include: (a) the hydrogeological characteristics of the rocks; (b) tectonic setting; (c) size and hypsometric position of the geological structures; (d) terrain morphology; (e) local and regional patterns of precipitation; (f) anthropogenic impacts; (g) main groundwater flow directions from the hinterland to the spring; (h) the spring type; (i) nature of the contact between permeable and impermeable rocks and, finally, (j) analysis of the balance between fresh and seawater in time and space. the hydrogeological characteristics of the various carbonate rocks in the study area were deduced from their lithological composition, amount of tectonic deformation on the surface, and detailed hydrogeological mapping of the robinzon spring area. sedimentary rocks were classified into three groups: highly permeable rocks, poorly permeable rocks and impermeable rocks (figs. 2 and 3). carbonate rocks, such as, for i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i 40 30 20 10 0 -10 -20 -30 -40 -50 -60 -70 -80 -90 -100 -110 ba m a.s.l. r-3 r-2 r-1 r-4 <2.8x10 -7 >2.3x10-6 <3x10 -7 <6x10 -7 >2.7x10 -6 <3.3x10 -7 <6x10 -8 <8x10 -8 >2.6x10 -6 ? ? i i 177o 0 10 20 30 40 50 m ? m/s r-4 1 2 3 4 5 6 7 8 9 legend: fig. 3 the hydrogeological cross-section of the robinzon spring area. legend: 1 – flysch; 2 – dolomite cataclastic breccia; 3 – quaternary deposits; 4 – boundary of the different water permeability; 5 – fault; 6 – thrust; 7 – undefined area; 8 – borehole with caverns; 9 – permeability in m/s. 143buljan, marković & peh: the effect of the seawater intrusion on the robinzon coastal spring example, jurassic karstified limestone, belong to the first group. the preferred groundwater flow paths (conduit flow) were formed in the carbonate rock complex due to secondary porosity (fissure dissolution), which is typical for karst terrains. this type of porosity together with considerable tectonic fragmentation and karstification is crucial for the high permeability of carbonate rocks in the hinterland of the robinzon spring. quaternary sediments such as the rockfall material, spring and anthropogenic deposits are also highly permeable. tectonically fractured dolomites and limestone belong to the transition group of poorly permeable rocks, while the eocene flysch series represents the group of impermeable sedimentary rocks. the latter is composed of marls and clayey marls occasionally interbedded with thin layers of limestone, limestone breccia, sandstone and silt. the hydrogeological characteristics of the sedimentary rocks in the particular geological setting of the robinzon spring area were used to determine their hydrogeological function. the narrow coastal zone of the clastic flysch strata extends ‘streamwise’ (into the sea) beyond the catchment area of the robinzon spring (fig. 2), but owing to its uniform regional extension and considerable thickness it plays a crucial role in the formation of the catchment. this zone separates the sedimentary complex with good reservoir and permeability characteristics from the sea, which is the ultimate recipient of the waters from the coastal hinterland. the absence of submarine springs in this part of the dubrovnik coastal area is caused by the hydrogeological barrier of flysch strata obstructing the groundwater flow to the sea. dispersed groundwater discharge from the karstified spring hinterland is blocked by the continuous impermeable flysch zone. thus, the total outflow is concentrated on a small number of springs because the groundwater can only reach the sea by flowing over the hydrogeological barrier. being a total hydrogeological barrier in the dubrovnik coastal area, the flysch strata extend from the slano settlement in the west to kotor bay (montenegro) in the east, a distance of approximately 70 km. only a few permanent and high-yield springs occur on the geological boundary with permeable carbonate rocks. the springs are characterized by the highest yields when situated at the lowest altitude where the flysch barrier is most deeply eroded. the portions of the adriatic coast where the flysch hydrogeological barrier is nonexistent (for example, the shores in the foothills of velebit mt. in the northern adriatic) are completely devoid of permanent springs, or springs of significant capacity because the subsurface waters from the coastal hinterland flow to the sea through the carbonate rocks in quite a diffuse manner. the highly permeable limestone of jurassic age is a predominant rock type but often interbedded with lenses, thin beds and zones of poorly karstified dolomites. due to their poor permeability the local dolomites are very important in directing groundwater flow into the permeable limestone sections of the carbonate rock complex. similarly, the slivnički fault zone acts as a significant hydrogeological factor because all the waters drained from the area are transmitted as concentrated flow through the very permeable fault zone to the hydrogeological barrier. the tectonic boundary between the carbonate rocks and clastic flysch sequence is considerably above sea level (230 m, fig. 2). the robinzon spring is a natural outlet, discharging water collected from the hinterland along the fault zone, because the erosion process strongly affected the carbonate rock sequence at the site. other significant surface springs or submarine springs cannot be found along the coastline. perger (19604) mentioned a few submarine springs but those have been subsequently buried and no longer exist. the fact is that a conduit water-flow only appears at the robinzon spring because the flysch zone hinders the dispersive water flow from the hinterland. this confirms by borehole determined hydrogeological function of the flysch sequence as a total barrier. dolomite rocks occurring at the thrust front, crushed by the dextral transcurrent faults, came into contact with flysch clastics and thus eliminated their primary role as a hydrogeological barrier. however, this is not observed in the spring zone where the highly permeable quaternary sediments occur. according to perger (19604), the robinzon spring has a natural yield varying between qmin = 20 l/ s (august 6, 1957) and qmax = 20.5 m3/s (january 4, 1954). during tunnelling works for the dubrovnik power plant, the cave system had been hit by drilling, which affected the maximum and minimum discharges on the spring outlet. the hydrogeological study of the metković–dubrovnik–konavle area (bojanić & ivičić, 19846) contains new information about the minimum qmin = 165 l/s (september 19, 1964) and maximum yield qmax = 2 m3/s (december 12, 1981). during the repair works at the power plant and the tunnel locations during may 2000, when the tunnel was drained for restoration for a period of 21 days, the loss of 240 l/s of water from the tunnel were found to feed the robinzon spring (paviša, 20007). 5. results and discussion four shallow boreholes with maximum depth of approximately 100 m below the surface, were planned in the robinzon spring area, in the impermeable flysch 6 bojanić, l. & ivičić, d. (1984): hidrogeološka studija područja metković–dubrovnik–konavle [hydrogeological study of the metković–dubrovnik–konavle area – in croatian].– unpublished report, archive of the croatian geological survey, zagreb, igi.186/84, 180 p. 7 paviša, t. (2000): analiza vode iz dovodnog tunela he dubrovnik [water analysis from the tunnel he dubrovnik – in croatian].– unpublished report, archive of the hrvatska elektroprivreda, dubrovnik, 30 p. 144 geologia croatica 59/2 formation (according to the geophysical data). however, only two reached the expected depth (boreholes r–1 and r–2), while the remaining two were terminated early (r–3 due to the failure of the drilling experiment). material drilled down to the impermeable flysch layer consisted of carbonate rocks: surface rockfall material (roughly to 20 m depth), followed by crushed dolomite rock, in places filled with limestone matrix, down to 111 and 100 m from the surface, respectively. data from the drilling experiment are summarized in table 1. the hydrogeological cross section through the robinzon spring area was compiled from various sources: geologic map data (lithology), core data from drilling intervals, tomographic measurements (andrić, 20013), and results of permeability measurements (fig. 3). the upper part of the cross section (light grey) is composed of fragments and pebbles of the dolomite rockfall material mixed with a clay–silt matrix, representing the highly permeable zone. effective measurement of rock permeability to be carried out at pressures of 0.5 and 1 mpa was impossible due to the significant loss of water, estimated at about 30–80 l/s, using darcy’s law for flow in a confined aquifer. permeability of the dolomites underlying the surface rockfall material exceeds 3x10-7 m/s. essentially, this zone is divided into the upper part where permeability is very high, ranging from 2.3 to 2.7x10-6 m/s, and the lower part where permeability is around 3x10-7 m/s, excluding the area around borehole r–2 where permeability is 6x10-7 m/s (fig. 3). this is the cavernous zone, channeling the groundwater flow from the carbonate hinterland to the sea. also, the tomography measurements detected the fractured zones at a distance of 5 m from borehole r–1 towards borehole r–2 at relative depths between -48 and -52 m. the permeability measured in this zone is 3x10-7 m/s, indicating the possibility of groundwater circulation. also, the temperature measured in borehole r–1 (fig. 3) is constant at 13.8°c. the measured data indicate a highly permeable zone between boreholes r–1 and r–2 down to the relative depth of -60 m. however, this zone becomes shallower in the direction of borehole r–2 (relative depth of -25 m,) and then deeper again toward borehole r–3 (relative depth of -42.4 m). the middle-grey coloured area in the cross section w a gw dol fl d r-1 5.38 4.38 17.60 103.60 111.00 r-2 2.41 1.40 19.80 89.91 100.00 r-3 2.52 1.42 7.20 42.40 r-4 9.44 8.15 22.80 90.00 table 1 general data on the drilling experiment at the robinzon spring locality. explanation: w – borehole; a – altitude (m); gw – relative depth of the groundwater level (m); dol – relative depth of the overlying permeable dolomite rock (m); fl – relative depth to the underlying impermeable flysch rocks (m); d – relative depth of the drilled borehole (m). borehole r1 depth (m) t (oc) ec (µs/cm) 5 15 25 35 45 55 65 75 85 95 13.0 13.2 13.4 13.6 13.8 14.0 14.2 14.4 14.6 14.8 t ( o c) 300 400 500 600 700 800 900 1000 1100 t e c borehole r2 depth (m) t (oc) ec (?s/cm) 5 15 25 35 45 55 65 75 85 13.0 13.2 13.4 13.6 13.8 14.0 14.2 14.4 14.6 t ( o c) 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 ec ( s/cm ) e c t t (oc) ec (µs/cm) borehole r3 depth (m) t(oc) ec (µs/cm) 5 10 15 20 25 30 35 40 13.8 14.0 14.2 14.4 14.6 14.8 15.0 15.2 15.4 15.6 15.8 16.0 335 340 345 350 355 360 365 370 375 borehole r4 depth (m) t(oc) ec (µs/cm) 10 20 30 40 50 60 70 80 13.45 13.50 13.55 13.60 13.65 13.70 13.75 13.80 13.85 13.90 13.95 340 350 360 370 380 390 400 t t e c e c fig. 4 variations of the ec and t with the depth during the pumping test. 145buljan, marković & peh: the effect of the seawater intrusion on the robinzon coastal spring represents the zone of the dolomite rocks where measured permeability is reduced to 2.73x10-7 m/s, except for the interval between -80 to -85 m (relative depth) in borehole r–2, where permeability is increased to 6x10-7 m/s (fig. 3). this zone is apparently devoid of caverns. however, tomographic measurements in borehole r–4 disclosed the fractured zone at the relative depth of -57.5 m (velocity of p waves 4000–4600 m/s). at this depth only the fractured rocks filled with clay have been drilled, the lowest permeability of which was measured at 2x10-8 m/s (fig. 3). the deepest part of the hydrogeological cross-section is represented by impermeable flysch deposits (dark grey) reached by drilling only in the two boreholes closest to the spring (table 1), so that the boundary between the carbonate and flysch deposits was only drawn approximately. thus the depth to the underlying impermeable flysch deposits farther from the spring in the e–w direction remains unknown as does the storage capacity of the carbonate block lying north of the spring area. the parameters such as temperature (t) and electroconductivity (ec) were computed vs. the depth diagrams constructed for all four boreholes at fixed time. such a diagram (t, ec vs. depth – fig. 4) shows the decrease of temperature down to a depth of -35 m in the case of the borehole r–1, which indicates the existence of groundwater flow (travi et al., 1995; falkowska & piekarek-jankowska, 1999). at greater depths, between -35 and -80 m, the temperature slightly increases, while in the deepest part of the boreholes, from -80 to -95 m, the increase of temperature with depth becomes linear indicating that the groundwater flow is nonexistent in this zone – a phenomenon called the bottle effect. furthermore, the ec value also increases in this interval, which is caused by mixing of the zones of freshand saltwater (weaver et al., 1995; mas-pla et al., 1999; land et al., 2004) in the borehole as in the contact zone between permeable dolomite and impermeable flysch rocks. for borehole r–2 the same diagram (t, ec vs. depth – fig. 4) shows the decrease of temperature down to the depth of -20 m, which again indicates the existence of groundwater flow. deeper down the borehole, between -20 and -65 m, the temperature slightly increases at first but in the deepest part, below -65m, the temperature and ec again increase linearly with depth as in the case of r–1. mixing of freshand salt-water is thereby confirmed in boreholes r–1 and r–2. in the case of the boreholes r– 3 and r–4 located farther from the spring with respect to r–1 and r–2 (along the cross section a–b) the conditions are analogous to the first pair of boreholes, and can be interpreted in the same way. the water level was measured both in the boreholes and at the water gauge near the spring. drawdown data were similar from boreholes r–1, r–2 and r–4, ranging between 0.10 and 0.11 m. a lowering of the water at the water gauge was slightly higher (0.13 m), due to its greater proximity to the spring. to increase the drawdown values, long-term pumping with higher capacity is required. natural waters acquire their chemical characteristics both by dissolution and by chemical reactions with solids, liquids and gases with which they come into contact during the various phases of the hydrological cycle (stumm & morgan, 1995). seawater intrusion into highly developed karst aquifers is a serious problem in many places along the coastal lines. it occurs where seawater is drawn into an aquifer with the decline in the hydraulic head causing the contamination of the coastal springs and boreholes (hem, 1985). chloride, which is the major anion in seawater, moves through aquifers at nearly the same rate as the intruding water. increasing chloride concentrations may be the first indication of seawater intrusion into the area devoid of other possible sources of saline contamination. again, magnesium and sulfate are present in seawater in much higher concentrations. a high mg/ca molar ratio may sometimes be indicative of seawater intrusion. many authors used the mg/ca and so4 2-/clratios as tracers for determination of seawater intrusion (e.g. vengosh et al., 2002; leboeuf et al., 2003). a wide range of so4 2-/clratios (0.02–0.23) is detected in groundwater in relation to seawater values (= 0.05; vengosh et al., 2002). sulphate and chloride concentrations vary from 7.5 to 16.3 mg/l, and 8.5 to 20 mg/l, respectively, ruling out a major influence of sea water on the spring (aquifer) (table 2). according to the chemical composition (piper diagram, fig. 5) the water from the robinzon spring belongs to the ca–hco3 hydrochemical type. this is the primary water type which is principally derived from dissolu date ph ca mg hco3 cl so4 2 ca mg clso4 2so4 2-/clmg/ca (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mmol/l) (mmol/l) (mmol/l) (mmol/l) 01/93 7.76 66 8.8 178 20 10.5 1.647 0.362 0.564 0.109 0.194 0.220 04/94 7.71 58 8.8 174 16 7.5 1.447 0.362 0.451 0.078 0.173 0.250 06/95 7.81 57 14 188 18 7.5 1.422 0.576 0.508 0.078 0.154 0.405 03/96 7.75 60 11 186 20 8.3 1.497 0.453 0.564 0.086 0.153 0.302 06/96 7.63 59 5.6 175 8.5 16.3 1.472 0.230 0.240 0.170 0.708 0.157 table 2 results of the robinzon spring water analysis (courtesy of the department of public health of the county splitsko–dalmatinska and ina department of fluid analysis and ecology). 146 geologia croatica 59/2 tion of carbonate minerals (calcite and dolomite) that compose the aquifer. also, the mg/ca ratio is very low, which is typical for freshwater flowing through the carbonate (limestone) aquifer. the chemical composition of the spring water shows that the spring is not greatly influenced by seawater and the flowing water from the robinzon spring is fresh water. 6. conclusions geological, structural and hydrogeological settings highlighted in this study have facilitated differentiation of the karst underground terrain of the robinzon spring area into three hydrogeological zones. the first is characterized by good water circulation (rockfall material, fractured and cavernous dolomite), the underlying second zone is of a poor water circulation (dolomites), while the third, deepest, zone “traps” the water (contact between dolomite and flysch). the increased values of ec were detected only at the bottom of the third zone in boreholes r–1 and r–2, where the tectonic boundary of highly permeable dolomites with underlying impermeable flysch strata was reached by drilling. such an increase definitely indicates seawater intrusion into the spring zone. the relationship between the sea and fresh water was not disturbed during the pumping test carried out under conditions of high or moderate discharges at the spring outlet. however, the vital question of what would happen if pumping was carried out during the dry period when the inflow of fresh water was small remains unanswered. to provide reliable answers it is necessary to complete the pumping test and to measure the various parameters (t, ec, major anions and cations) from the water samples from the robinzon spring, and from the neighbouring boreholes r–1 and r–2 during both the rainy and dry seasons of the year. the results would pave the way for understanding whether the deeper parts of the aquifer represent an isolated hydrological system (siphon without circulation), or are they connected with other parts (underground flows). they would also provide answer regarding possible contamination of the drinking water by saline water at the pumping station as a result of seawater intrusion. acknowledgements the authors wish to express their gratitude to department of public health of the county splitsko–dalmatinska and ina department of fluid analysis and ecology that provided water chemistry data. we also wish to acknowledge the help of mr. tomo paviša. 7. references buljan, r. (1999): značenje strukturnog modela u razradi zahvata i zaštite podzemnih voda izvorišta područja ombla kraj dubrovnika [the significance of the structure model in the groundwater capture and protection of the ombla spring area near dubrovnik – in croatian].– unpubl. phd thesis, university of zagreb, faculty of mining, geology and petroleum engineering, 176 p. cat i ons an i ons%meq/l na+k hco +co3 3 cl mg so4 ca calcium (ca) chloride (cl) su lfa te( so 4) +c hlo rid e( cl ) calcium(ca)+m agnesium(mg) ca rb on ate (c o3 )+ bi ca rb on ate (h co 3)sodium (na)+potassium(k) sulfate(so4)ma gn es ium (m g) 80 60 40 20 20 40 60 80 80 60 40 20 20 40 60 80 20 40 60 80 80 60 40 20 20 40 60 80 20 40 60 80 80 60 40 20 80 60 40 20 01/93 04/94 06/95 03/96 06/96 fig. 5 piper diagram of robinzon spring water; samples taken in january 1993, april 1994, june 1995, march and june 1996. 147buljan, marković & peh: the effect of the seawater intrusion on the robinzon coastal spring buljan, r. & prelogović, e. (1997): the significance of structural and geological relationship assessment in the construction of the ombla underground hydroelectric power plant.– rgn zbornik, 9, 17–22, zagreb. falkowska, l. & pienkarek-jankowska, h. (1999): submarine seepage of fresh groundwater: disturbance in hydrological and chemical structure of the water column in the gdansk basin.– ices j. of marine science, 56/1, 153–160. hem, j.d. (1985): study and interpretation of the chemical characteristics of natural water.– u.s.g.s. water supply paper 2254, 263 p. herak, m. (1977): tektonogenetski pristup klasifikaciji krških terena [tectogenetic approach to determine karst terrains – in croatian].– krš jugoslavije, 9/4, 65–80, zagreb. herak, m. (1986): a new concept of the geotectonics of the dinarides.– acta geologica, 16, 1–42, zagreb. herak, m. (1991): dinaridi – mobilistički osvrt na genezu i strukturu (dinarides – mobilistic view of the genesis and structure).– acta geologica, 21/2, 35–117, zagreb. hubbard, s.s. & rubin, y. (2000): hydrogeological parameter estimation using geophysical data: a review of selected techniques.– j. of cont. hydrology, 45/1–2, 3–34. land, m., reichard, e.g., crawford, s.m., everett, r.r., newhouse, m.w. & williams, c.f. (2004): groundwater quality of coastal aquifer systems in the west coast basin.– los angeles county, california, 1999–2002. u.s.g.s. and u.s. dep. of the interior. sci. report 2004–5067, 40 p. leboeuf, p.p., bosch, p.a., calvache, m.l., vallejos, a. & andreu, j.m. (2003): strontium, so4 2-/cl and mg2+/ca2+ ratios as tracers for the evolution of seawater into coastal aquifers: the example of castell de ferro aquifer (se spain).– c.r. geoscience, 335, 1039–1048. marković, b. (1966): osnovna geološka karta sfrj 1:100.000. list dubrovnik k34–49 (basic geological map of sfrj. dubrovnik. sheet).– zavod za geol. i geofiz. istraživanja beograd (1963–1965), savezni geološki zavod beograd. marković, b. (1971): osnovna geološka karta sfrj 1:100.000. tumač za list dubrovnik k34–49 (basic geological map of sfrj. geology of dubrovnik. sheet).– zavod za geol. i geofiz. istraživanja (1966), savezni geološki zavod beograd, 43 p. mas-pla, j., bach, j., viflas, e., trilla, j. & estralrich, j. (1999): salinization processes in a coastal aquifer system (alt emporda, ne spain).– physics and chemistry of the earth. part b: hydrology. oceans and atmosphere, 24/4, 337–341. milanović, p. (1977): hidrogeologija karsne izdani ombla [hydrogeology of the ombla spring – in croatian].– geološki glasnik, sarajevo, 35–48. stumm, w. & morgan, j.j. (1995): aquatic chemistry. chemical equlibria and rates in natural waters.– john wiley & sons. inc. new york – chichester – brisbane – toronto – singapore, 1022 p. travi, y., pizard, p. & betton, m. (1995): temperatures and thermal gradients in the senegalese maastrichtian aquifer: simulated test on their effect on flow discharge.– j. hydrology, 167/1–4, 99–119. vengosh, a., gill, j., davisson, m.l. & hudson, g.b. (2002): a multi-isotope (b, sr, o, h and c) and age dating (3h–3he and 14c) study of groundwater from salinas valley, california: hydrochemistry, dynamics and contamination processes.– w.r. resources, 38, 352–363. weaver, t.r., frape, s.k. & cherry, j.a. (1995): recent cross-formational fluid flow and mixing in the shallow michigan basin.– geol. soc. of america bulletin, 107/6, 697–707. manuscript received september 10, 2006. revised manuscript accepted november 24, 2006. 148 geologia croatica 59/2 geol. croat. zagreb 1998 upper cretaceous palaeogene tholeiitic basalts of the southern margin of the pannonian basin: pozeska gora mt. (croatia) mirko belak', josip halamic', vesna marchig2 and darko tibljas3 key words: tholeiitic basalts, upper cretaceous­ palaeogene, upper mantle, pannonian basin, poze­ ska gora mi., croatia. abstract according 10 the geological relationsh ips in the region of poze­ ska gora mi. (the southern margin of the pannonian basin, norlhern croatia), basic erupti ve rock s are considered to be of upper creta­ ceous palaeogene age. detailed petrographic examination, based on phys iographic descri ption, th e chemical composition of major and trace elements, rare earth elements and stable isotopes, indicates that (hese primary tholei it ic basalts have variable structural-textural chara­ cterist ics, and we re postmagmatically affected by metamorphic processes . tholeiitic basalts originated from the upper mantle, and were placed in the form of subaquatic effusions in the extensional zones withi n continental crust. 1. introduction pozeska gora mt. is located in the transitional zone between the tis ia tectonic megaunit and the inner dinarides (fig. 1; kovacs et ai., 1989; haas et ai. , 1990; sikh:, 1995; herak et ai. , 1990). basic rocks represent part of the magmatic complex of the ne part of the pozeska gora mt. , which is also composed of alkal i-feldspath ic granites and rhyolites (fig. 2). petrograph ic examination s of the basic magmatic rocks of the pozeska gora mt. have prev iously been incomplete, compri s ing part of investigation of the magmatic complex as a whole (koch, 1917; tucan, 1919; baric & tamer, 1942; tamer, 1947, 1955, 1959; sparica et ai., 1979, 1980; majer & tamer, 1982). pamic ct a1. (l990) concluded that basal t magmas originated from the upper mantle, and that they are connected with continental areas. they included basic rocks within the bimodal volcanic asso­ ciation. i inst itute of geology, sachsova 2, p.o.box 268, hrloooo zagreb, croatia. 2 bundesanstalt fur geowissensehaften und rohstoffe, hannover, germany. ~ faculty of science, department of geology , insti tute for mineralogy and petrology. horvatovac bb, hr-1 0000 zagreb, croatia. on the basis of geological data koch ( 19 17,1919), taksic (1944) and sparica et a1. (1979, 1980) determined that the volcanic rocks are of tertiary age. however, discovery of "scaglia" limestone layers with­ in the basalts led pamic & sparica (1983) to their conclusion of an upper cretaceous age. halamic et al. (1990) interpreted these limestone occurrences as enclaves, which together with structural measurements, was used as an argument for a post-maastrichtian, i.e. post-laramian age for the basic volcanic rocks of the pozeska gora. however, majer & t ajder (1982) proposed that these rocks represen t an allochtonous block, and that they are, according to their similarity with the rocks in the other parts of the dinarides, of tri­ assic age. isotopic k-ar analyses undertaken by pa· mic et a1. (1988) determined the age of the acid mag· matic rocks withi n the bimodal volcanic association as 71.5 ± 2.8 ma, thus reaffirming an upper cretaceous age. 2. basic geological data the magmatic complex of the pozeska gora is bounded on the northern margin by neogene and qua­ ternary sediments, in a partly tectonic and partly ero­ sional -tectonic contact (fig. 2). their southern margin is characterised by a tectonic contact with upper creta­ ceous deposits (fig. 2). acid eruptive rocks, which are the major part of the magmatic rocks, are represented by alkali-feldspathic granites, i. e. alaskitcs and alkali ­ feldspathic rhyolites (pamic, 1988; pamic et a!., 1990). basic rocks mostly occur southeas t of pozega, between the vidovci and komusina vil1ages, where along the northern margin they are in the contact with rhyolites and rhyolitic tuffs, and to the south are cov­ ered by neogene sediments (fig. 2). furthelltiorc, these rocks have been found southwest of pozega, south of drskovci vil1age, where they are in tectonic contact with granites and rhyolites. a major part of the basalt body is composed of more or less altered basalts of different stmctural and textural vari eties , which are presented as a singl e unit on the geological map, since it was not possible to divide them into units appropriate for geological mapping. at some localities pillow lavas have been found, proving that the 164 geologia croatica 51n maribor ........ novo ." mesto " n a 10 o 30km fig. 1 tectonic scheme of the basement in the sw part of the pannonian basin (from sikic, 1995). basaltic rocks originated from subaquatic effus ions (fig, 3a), the second group of basic rocks of the poze­ ska gora is composed of hypoabyssai rocks, i.c. diabas­ es and subordinate gabbrodiabases. they arc rather fre­ quently represented as veins in granites (fig. 4a) and rhyolites (fig. 4b). diabase veins have also been found in thc uppcr cretaccous sediments north of bod lis (fig. 2). in addition basic effusives and vein rocks, volcanic agglomerates, and basic tuffs have been discovered. in the basaltic body there are several occurrences of reddish to gray-reddish pelagic limestones which are up to 1.5 m thick, and of restricted lateral extent (fig. 3b). these rocks are mostly sandy biomicri tes, micrites and sparites. non-carbonate detritus comprises quartz gra­ in s, fine-grained muscovite, opaque minerals and a clayey-haematitic substance . findings of globotrun­ canid foraminifera indicate their upper cretaceous age (pamic & sparica, 1983) . at several localities al ­ ong the nakop creek, limestones are accompanied by acid tuffs. boundaries between sedimentary rocks and basaltic lavas are almost always sharp and without load casts, and reactional boundaries are characterized by the recrystallization of limestones and loss of their haematitic component, as well as a decrease in grain size of the basalts ("frozen margin") . on this basis we may conclude that these limestones were enclaved dur­ ing effusion of lava on the sea bottom , and that the basic effusives are younger than the sediments. 3, petrology the analysed samp les were collected during work on ihe geological map of the republic of croatia (scale 1 :50.000) during 1989 and 1990. the modal composition was determined by optical and x-ray diffraction methods. major elements were analysed in the institute of geology, zagreb, by grabelak. halmn ic. marchig & tibljas: upper cretaceous palaeogene tholeiitic ba.~a lts .. , ~' '. " .. ] ... ~ ~ m ~ '" ~ ~ ;:: lsj <:> ~ ~ ~ ~ '" lsj ~ d '" d . . ~ ~ ... m 165 fig. 2 geo logica l map of the magmalic complex of poie­ ska gora m i. legend: i ) ba­ salt s: 2) diabase veins; 3) rhyolites: 4) granites; 5) up­ per crc taceous sedimentary rocks; 6) teni ary sedimen­ tary rocks: 7) quaternary: 8) di scordant boundary; 9) bo­ undary of effusive volca nic body; 10) faul t: normal. tra­ nsc urrent: i i) reverse faul t: 12) gravitational sli ding: 13) re lat ive ly subsided block; 14) gravitat ional overth rust. 166 geolog ia cro:llica 5 [/2 fig. 3 a) pillow lavas in the nakop quarry: b) enclaves of upper cretaceous pelagic limestones in basalts in the pako quarry. vimctry, spectrophotometry and flame photometry, and some of the samples were analysed by xrf allhe bun­ desanslall fur geowissensehaflen lind rohsloffe (bgr) in hannover (table 1). trace elements were de tcnnined al ihe ruder boskovic inslilule in zagreb , and at bgr in han nover by xrf (table 2). thc accuracy of the determinations was tes ted with international standards and was in all cases better then ±5%. rare earth con­ tent s were determined by inductively coupled plasma mass spectrometry (icp-ms) al bgr hannover (tabl e 3) . the accuracy of these analyses is also bette r than ±5%. the d iag ram s o f streckeisen (1967, 1978) were used [or class ification of the basic volcanic rocks. three diffe renl basic rocks were determined: a) basalts, b) diabases and gabbrodiabascs, and c) volcanic agglo­ merates and basic tuffs. a) basalts arc composed of basic plagioclase (la­ bradorite), alb ite and pyroxene. secondary components, besides albite, are chl orite, epidote, calcite, prehnite, pumpell yite, sericite, quartz and zeolite, and accessory are ilmenite, magnetite and apatite. basic plagioclase is completely altered into acid plagioclase in approxi­ male ly 80% or the analysed rocks, while in 20 % of basalts basic plagioclase is preserved, but rarely unalte­ red, because of prehnitization and sericit ization. on the basis of structural and textu ral characteristics basalt s a re di v ided into several g roups: fin e-grained , medium-grained, coarse-grained , porphyritic and vesic­ ular. fine-grained basalts with grain s up to 0.5 mm in size most ly have typical o phitic texture, while those wi th subophitic, intergranular, di vergent-radial , skele­ tal -arborescent and hyalopillitic texture are not so fre­ quent. their structure is homogeneous and ves icular. medium -grained basalts arc composed of grain s ranging in size from 0.5 1 mm. their texture is ophitic, intergranular and subophiti c, and stru cture ho moge­ neous, infrequently vesicular. coarse-grained varieties have grains coarser than 1 mm, ophitic texture and homogeneous structure. porphyritic basalts are characterized by porphyrit ic texture and a homogeneous or ves icular structure. in the fine-g rai ned matrix, composed of any of these textural va riet ies of fine-grained basalts , are phenocrysts of pla­ gioclase and clinopyroxene, up to 3 mm in size, wh ich are present either as isolated grains or as agglomerates. vesicular basalts are characterized by their vesicular structure, which is macroscopically visible. vesicles are 0. 15-3 mm in size, usually of circular or slightly e ll ipti­ cal shape. monomineralic vesic les are fi lled with cal­ c ite, infrequently with chlorite and very rarely with quartz. polymineralic vesicles are fill ed with the mlnerfig. 4 <i) diabase vein in granites ( 1.2 km ne from gradski vrhovc i village) ; b) diabase vein in rhyol ites (2 km sw from ku zmica village). ;? '" " 0 g sample 1 2 3 4 5 6 (ng8') (nj5') (351) (755) (2810) (pc7) ~ ;:::3: ~t 03 , 0 0-':: ~ 0 sio~ 49.04 45.43 50.93 44.73 45.14 45.96 ti02 2.86 3.16 286 2.31 2.53 1.24 aip3 15.03 14.57 14.73 15.60 14.53 15.94 fep3 11 .782 15.132 11 .702 5.50 7.92 3.97 feo 6.08 5.97 5.05 moo 0.15 0.20 0.17 0.18 0.17 0.14 00 ~ 5 ~~ m90 3.42 5.55 3.60 3.83 3.53 7.25 cao 6.74 6.51 6.02 9.01 9.93 9.25 na20 4.50 2.32 3.24 3.04 4.25 4.61 ~ 5 ~ §q ~" t;. :< g ~ 'f. 0 :'3 ",:r. k,o 0.43 0.92 1.07 0.38 0.30 0.58 pps 0.34 0.37 0.29 0.56 0.71 loi 5.72 5.28 4.85 8.76 4.91 5.75 total 100.01 99.44 99.55 99.98 99.89 99.74 co, 2. 47 1.80 3.09 3.89 3.90 h,o 2.80 3.58 0.96 4.87 1.01 ;;h" &0":; 0-" x ' o ?;0 :" si0 2 53.80 49.44 56.16 51.85 50.14 48 .89 tio 3.14 3.44 3.11 2.67 2.81 1.32 -=: ' '" ~ 00 0~ cl ~ ~ " ~f :2 ~ ~ .::: 6' " &3 0;. o 3 "6' o 0 p 3 k 1:[ g .~ o ~ -» o-~ ~ ~ :;.;3 5~ ~o aip3 16.49 15.86 16.03 18.08 16.14 16.96 fe 2 0 3 12.92 16.46 12.73 6.37 8.80 4.22 feo 7.04 6.63 5.37 moo 0.16 0.22 0.18 0.21 0.19 0.15 mgo 3.75 6.04 3.92 4.43 3.92 7.71 cao 3.95 4.60 2.27 4.71 5.52 9.84 nap 4.94 2.52 3.52 3.52 4.72 4.90 k,o 0.47 1.00 1.16 0.44 0.33 0.62 pps 0.37 0.40 0.31 0.65 0.79 feo"/feo+mgo 1.03 0.90 1.02 1.17 1.46 0.73 fep3:feo 0.62 0.47 0.63 0.90 1.32 0.78 cao/na2o+kp 0.77 1.30 0.48 1.19 1.09 1.78 0 8.1 8.9 19.5 10.7 c 1.5 3.2 5.6 4.8 oc 2.8 5.9 6.9 2.6 1.9 3.6 ab 42.1 21.5 30.2 29.8 40.1 24 .5 ao 17.3 20.4 9.3 19.2 21.4 22.5 ne 9.2 ~3 o-~ ~ 0 'f. 'p. o -. ?' =. g ~ ~ g§. :;.di 0.3 21.3 hy 14.4 35.0 14.7 20.1 01 21.4 12.2 ml 6.8 7.2 6.7 6.1 6.23 4.1 hm 11 6.0 6.6 5.9 5.0 5.3 2.5 ru ap 0.8 0.9 0.7 1.5 1.8 pi norm 29.1 48.6 23.6 39.1 35.3 36.0 c.1. 27.2 38.8 27.5 31.3 33.5 40.0 d.1. 53.0 36.4 56.6 39.1 42.7 37.4 5. 7 8 9 9a 10 11 12 13 14 15 16 (na3) (nj·2) (v da2) 9a (74 1) (782) (mc1) (131sa) (pc· l ) (pd·1 2) (vda4) 49.11 55.06 47.66 48.12 43.62 47.91 46.2 47.28 44.41 45.51 47.19 1.77 3.04 1.65 2.38 1.44 1.93 1.85 1.75 1.48 1.00 2.07 17.85 15.43 14.79 15.38 12.83 14.92 16.58 16.52 13.26 20.78 17.02 5.59 2.73 7.60 5.27 7.322 7.14 6.08 5.68 5.89 5.12 9.09 6.28 5.61 4.24 6.47 5.60 5.30 6.20 3.13 3.12 1.52 0.10 0.22 0.17 0.16 0.1 0.18 0.17 0.20 0.14 0.12 0.11 1.71 3.53 4.93 4.15 1.41 4.03 3.32 5.74 3.22 6.15 1.51 6.72. 5.47 8.27 7.54 18.24 10.77 11.02 8.07 15.68 10.23 10.11 4.26 4.69 4.96 3.98 2.73 3.60 3.60 3.18 2.43 2.54 3.62 1.92 0.99 0.19 0.75 0.59 0.58 1.10 0.83 0.30 0.30 0.03 0.70 0.49 0.16 0.48 0.75 0.39 0.55 0.96 4.25 2.91 4.38 5.20 11.15 2.81 4.02 3.92 9.41 4.85 6.65 99.56 99.68 99.54 99.89 99.59 99.95 99.99 99.76 99.90 99.72 99.98 2.65 7.60 0.00 2.41 1.48 7.22 2.78 1.73 3.55 2.81 1.61 2.44 2.19 3.87 chemical analyzes calculated on hp and caco) free basis 51.52 56.89 51.92 52.29 55.36 49.32 49.73 50.32 54.61 47.97 52.6 1.86 3.14 1.79 2.58 1.83 198 1.99 1.86 1.81 1.05 2.30 18.73 15.94 16.11 16.70 16.28 15.35 17.84 17.58 16.30 21.9 16.97 5.86 2.82 8.27 5.60 9.29 7.35 6.54 6.04 7.24 5.39 10.13 6.59 5.79 4.62 6.78 5.76 5.70 6.59 3.84 3.28 1.69 0.10 0.23 0.18 0.18 0.12 0.18 0. 18 0.21 0.17 0.13 0.12 1.79 3.65 5.37 4.50 1.78 4.15 3.57 6.10 3.95 6.48 1.68 7.05 5.65 5.34 5.43 10.89 11.08 8.55 6.58 8.00 10.77 7.33 4.47 4.85 5.40 4.31 3.46 3.70 3.87 3.38 2.98 2.67 4.03 2.01 1.02 0.21 0.80 0.62 0.59 1.18 0.88 0.36 0.32 0.03 0.76 0.54 0.20 0.49 0.80 0.41 0.67 1.07 1.48 0.91 1.29 1.12 1.16 1.32 1.32 0.99 1.42 0.88 3.00 0.88 0.49 1.79 8.87 0.62 1.27 1.14 0.91 1.88 1.64 5.90 1.08 0.96 0.95 1.06 2.67 2.58 1.69 1.54 239 2.16 1.80 7.6 11.1 12.2 10.6 1.5 11.9 6.0 1.2 3.6 3.5 6.9 6.9 2.1 1.9 0.2 37.9 41.0 45.9 229.5 31.4 32.8 28.6 25.3 22.7 34.2 25.1 18.7 19.2 27.2 23.6 27.9 30.0 30.1 47.0 29.5 8.4 7.5 2.0 18.8 23.5 7.8 4.3 5.4 0.2 9.0 15.4 2.3 10.69 26.3 15.9 8.7 11.4 7.9 6.2 5.6 2.9 8.6 5.0 4.1 4.7 4.8 5.0 5.0 4.8 4.8 3.8 5.5 3.5 6.0 3.4 3.5 3.8 3.7 3.5 3.4 2.0 4.3 1.7 0.4 1.1 1.8 0.9 1.5 24 39.8 3 1.3 29.4 48.0 42.9 45.9 51.1 54.3 67.3 46.2 25.0 26.5 32.0 26.1 40.2 30.3 34.7 28.5 28.4 21.3 49.8 54.6 47.0 44.3 34.9 39.8 34.1 39.7 24.5 45.0 17 18 (k81) (nm1) 46.44 50.97 1.75 1.89 15.43 17.60 7.53 4.53 4.54 4.55 0.18 0.13 5.54 4.04 9.25 7.71 2.80 1.89 0.32 1.41 0.49 5.54 4.84 99.89 99.53 2.41 3.13 50.92 53.82 1.91 1.99 16.91 18.58 8.25 4.78 4.97 4.80 0.19 0.14 6.07 4.26 6.77 8.14 3.07 1.99 0.35 1.48 0.53 1. 19 1.05 1.65 0.99 1.97 2.34 4.4 11.2 0.4 2.0 8.8 26.1 16.9 30.3 37.4 2.4 26.7 14.2 4.9 5.2 3.6 3.8 1.2 53.7 68.9 35.3 25.7 32.6 36.8 19 (845) 47.20 0.53 16.19 5.10 5.29 0.16 5.54 12.46 3.22 0.80 0.37 3.04 99.90 0.83 2.21 49.26 0.55 16.89 5.32 5.52 0.17 5.78 11.89 3.36 0.83 0.38 0.95 0.96 2.83 4.9 23.7 28.6 2.5 23.1 11.9 2.9 1.0 0.9 50.5 39.1 31.3 19a 46.67 1.57 16.11 595 4.46 0.16 4.05 11.35 2.96 0.64 0.51 5.65 100.08 51.39 1.73 17.66 6.43 4.75 0.16 4.38 g.o 3.25 0.66 0.56 1.32 1.69 2.19 i'i " ?' ". [ ?i; " ~ ". r> ..; 0-= ~, c ~ () a i ;j .,i o g g; ~. ~ f ~ ~ 168 geologia croatiell 51/2 1 2 3 4 5 9 10 11 12 13 14 16 17 19 (ng8') (nj5') (35') (755) (2810) (vda2) (74') (782) (mg') (1318a) (pg1) (vda4) (kb1) (845) ba 124 164 111 154 112 107 81 78 238 136 282 175 165 354 co 38 45 40 26 cr 67 160 140 189 cu 28 18 24 27 ga 30 28 23 26 hi 18 18 18 18 mo 4 4 4 4 nb 20 21 19 12 ni 23 26 34 23 rb 14 28 35 27 5 5 15 12 32 27 5 9 5 23 sn 30 35 39 36 31 52 49 29 35 50 31 41 30 29 sr 175 147 202 199 165 234 139 181 251 181 265 206 225 353 v 341 337 315 198 300 159 238 150 266 196 73 174 238 92 y 37 48 39 20 41 34 17 26 31 21 23 37 21 18 zn 111 123 108 96 119 113 34 114 11 1 80 84 120 99 64 zr 214 235 189 78 205 227 105 97 182 180 114 194 120 66 table 2 trace elements contcnls (in ppm). table 1 is the numeration key for samples. al association ± calcite ± chlori te ± epidote ±quartz ±pre­ hnite ± pumpcilyit ± haematite ± zeolite. b) diabases and gabbrodiabases only occur as dy­ kes and s ill s which cut both the entire magmatic com ­ plex, and sed imentary rocks of upper cretaceous age. diabases have ophitic texture, a homogenous structure, and could be divided, on the basis of their textural and structura l charac teris tics into medium-grained, coarse­ grained and weaklyporphyrit ic lypes. major mineral components are basic plagioclase or albite and clinopy­ roxene. secondary components include albite, chlorite, epi dote, calcite, prehni le and sericite, while accessory components are opaque minerals and apat ite. 74 ng8 nj5 35 la 6.8 16 17 15 ce 16 38 43 35 pr 2.2 5 5.7 4.7 nd 11 23 27 22 sm 33 6.1 7.6 6.5 eu 1.2 2 1.9 1.6 gd 2.9 6.2 7.1 5.7 tb 0.52 0.96 1.2 0.96 dy 3.9 6.9 8.3 6.9 ho 0.69 1.3 1.6 1.3 er 2.1 31 4.78 3.8 tm 0.33 0.56 0.72 059 yb 2.4 4.3 5.3 4.4 lu 0.35 0.61 0.80 0.64 table 3 rare earth clements contents (i n ppm). table i is the ilumcration key for samples. gabbrodiabases are characterized by hypidiom or­ phic texture and homogeneous structure. the major mineral components are plagioclase and hornblende, secondaries include chlorite, epidote and calcite, while magnetite and apatite are accessories. c) volcanic agglomerates and basic tuffs occur much more infrequently than other types of basic rocks. volcanic agglomerates have psephitic texture and mas­ sive st ructure. c lasts of different textural-structural ty­ pes of basalis, or subordinate rhyolite, are 10-100 em in size. the matrix is composed of weakly cemented tuffaceous material basic tuffs are represented by thinner beds within the success ion of basalts and volcanic agglomerates. they were divided into vi trocrystalline, crys talldvitro­ phitic and vitrophitic types. 4. mi neralogy plagioclase (labradorite) has a prismatic shape, is usually prehni tized or sericitized, only infrequently fresh. its modal component in basalt and diabase is approximately 55 %. the mean content of anorthi te was determined by optical measurement as 57.9 %. the mean normative composition of pl agioclase is 52 .8% an (table 1). therefore, optical and normative values indicate that the p lag ioclase is a labrador ite, what is a lso confirmed by roentgen analysis indicating neutral to basic plagioclase. the clinopyroxene (augite) is of short -pri smat ic, a rticulated or feat herlike form. it is one of the major mineral components of basalt and diabase, with a modal content of up to 30 %. l3c1ak. halamic. marchig & tibljas: upper cretaceous palaeogene tholeii tic basalts". 169 hornblende is the major mineral co mponent of gabbrodiabase dykes, while only in one type of basalt it does represent a late-magmatic m ineral. limcljitc, magnetite and apatite are accessory minerals in all basic effusive rocks of poieska gora mt. albite is the most important mineral in a ltered ba­ salts and diabases, since there are almost no samples of basic magmatic rocks showing no evidence of albitiza­ tion. it is most frequentl y of prismatic, twig-like an d needle -like form, and is inhomogeneou s, with inclu­ sions of epidote/cl inozois ite and chlori te . the mean anorthite compo nent dctcrmined by optical measure­ ments is 5.5 %, and by roentgen diffract ion it was deter­ mined as acid to neutral plagioclase. the mean value of normative composition is 34.4 % an (table j). norma­ tive values arc not in concordance with the results of optical determinations. thi s could be explained by inc­ luding one part calcium from the postmagmatic miner­ als epidote, prehn ite and pumpelly it e into nonnative plagioclase. also, there is a possibi lity that the alb it iza­ tion process is not complete, but it was not possible to prove this optically because of the very small number of plag ioclase grai ns appropri ate for theodol it ic mea ­ surements. c hlorite was fou nd in all samples of the basic rocks. it is present in small veins, vesicles or in inter­ granu lar spaces in the form of very fine aggregates. the approximate formula of chlori te which occurs in vein­ lets in basalts from nakop c reek was calcul ated from x-ray powder diffrac tion data fo ll ow ing the procedure proposed by nieto (1997). accordiog to the obt ai ned formula (mg,,,pe rnai i. i) ) (s ij.07 alo.oj) ° iii(oh)8 <md valid division of the chlori te group minerals (ne­ wman & brown, 1987) this chlorite could be deter­ mined as ferroan clinochlore. epidote is present as an inc lusion in acid plagio­ clase , in the matrix as gra iny aggregates or in fissure systems in the rocks where it represents the most com­ mon mineral. on the bas is of the diffrac togram of the epidote from veins in the basalts of pako and nakop creeks, unit ce ll dim ensions were calcu lated, and using the eqllaiion oj' carflonin & molin (1980) the fol­ lowing fonnulae of these two epidotes were obtained: c", (ai, ."peo.co) (si, o, ) (si o.,)o(ob), and ca2(ai 233 peo77) (si , o, ) (s i 04)0 (oh) . calcite most frequent ly fills vesicles in the rock , but is also present in small joints and as irregular aggre­ gates. tn the rock matrix it is usually agglomerated wi th epidote and chlor ite. tn open fissures colourl ess calci te crys tals lip to i cm in size were found , wi th hexagonal pri sm surfaces and basal pinacoicls. p rchnite substitutes plagioclase, and in some sam ­ ples plag ioc lase is completely prehnitized. it is also prese nt in the form of small ve ins. it was determined by both optical and roentgen methods. sericite is uncommon and subst itutes plagioclase. quartz usu ally fills small veins, more rarely vesicu­ lar fabrics, and very infrequently in te rstitial spaces. pumpellyite was found in small veins and vesicles in metabasalts, and was determined by the optical and roentgen diffraction methods. haematite fi ll s veins and was found in irregu lar aggregates in the form of a soil-like substance, and was de termined by optical and roentgen diffraction meth­ ods. pyrite is present along fi ssures in the form of small agglomerates, while coarse r crystals were found in ba­ salt dykes. zeolite fills only vesicles in some varieties of meta­ basalts from maj dan creek, and was determ ined by optical measurement. 5. geochemistry from the results of chemical analyses presented in t able i it is obvious that the major element contents show a certain amount of va riab ility , most frequent ly caused by different contents of secondary calcite and by other secondary processes . in chem ical analyses calculated to 100 %, without ign ition lo ss and cac03 (tablc l) , the si02 content var ies from 47.97-56.89% (x=51.84%). therefore some rocks could be determined as neutral , and most of the rocks as basic according to streck eisen (1978). total fe oxide content is rather more uniform, with cer­ tain variat ions (x= li.4s %). the mean value of pe,0, : peo ratio is 1.28 (table i). total ce oxide con­ tents is higher than the mgo contents , which is more variable ( 1.79 7.71 %). alkali content is variable, mostly depending on th e degree of the a lbiti zation or the rock, and na20 contents (x=3.78%) is hi gher than the k20 content (0.73% on average). ti02 content is interesting, ranging from 0.55 % in a gabbrodiabase vein to 3.44% in some varieties of basalt. harker's dia­ gram s in d icate tha t an increase o f si02 also increases the alkali conten t, and decreases cao and p]o, content, wh il e an increase of mgo slightly decreases the cao, na20 and p20::; va lues. pe trochemica l characteri stics or major clements, trace clements and c ipw normative composition indicate that analyzed rocks be long to the tholei itic basalts. a geochem ical mode l of values normal ized on morb (pearce, 1983) indicates higher normalized contents of k, rb and ba (fig. 5). l neompatib le cle­ ments arc enriched, except y and yb, whose relation is similar to n-morb. such a model has normalized trace elements simila r to continental tholeiit ic basal ts. a geochem ical mode l of values normalized on chondrite (thompson , 1982) shows relatively high 170 sr k rb6a th ta nb ce p zr hi smti y vb fig. 5 diagram of truce elements normali zed on ivl0rb (pearce, 1983). ratios of rb and k, and a clearly expressed negative anomaly o[ sr (fig. 6). a decrease in sr could be exp[a­ ined by low-pressure fractionation of plagioclase, while the gcochcm ically normalized model indicates that the primary magma originated from the enriched mantle or crustal contamination of magmas. the zr/nb ratio in analysed samples ranges from 9.7s [0.7 (average 10.1), indicating that the magma originated from an enriched mantle, as the values for n­ morb are higher than 30 (wilson, 1989). a three-component diagram for basalts lall 0y/is nb/8 (cabanis & lecolle, 1989) indicates that basalts of the pozeska gara mt. belong to the e­ type o[ mors (fig. 7). for study of the geotectonic position, a discrimina­ tion diagram ti/loo-zry (pearce & cann, 1973) v/is 43 58 ia lall 0 nb/8 fig. 7 diagram lailo y/15 -nb/8 for basalts (caban is & leco­ lle, 1989). leg end: i) volcanic -arc basa lts (ia calc-alkali basalts; i b an area overlap between i a and i c; ie volcanic­ ilrc tholeiites); 2) continental basalts (2a continental basalts; 28 back-arc basin basalts); 3) oceanic basalts (3 a alkali basalts from intercontinental rift: 38 e-typc morb-enriched: 3c e­ type mors -weakly enriched; 3d n-lype morb). geologia croaliea 51/2 barbth k nbtalacesr ndpsmzr hili tby tmyb fig. 6 diagram of trace elements normalized on chondritc (thomp­ son,1982). was used, where points of basic volcanitcs from pozc­ ska gora [all within the d tleld, i.e. in the ileld of with­ in-plates basalts (fig. 8). on an nbx2 zr/4 y diagram (meschede, [986), the analysed basic volcani tes [all in the field of within-plates tholeiites, which is also the rield of basalts of the volcanic arc (fig. 9). values of ti and v were plotted on the diagram (after sherv ais, 1982), where points ind icate a trend of oceanic island basalts (fig. 10). a geochemical model of the rare earth elements normalized on ehondrite (fig. 11) shows la contents approximately 50 times greater than in chondrites with a gent le negat ive inclination of the curve (ce/ybn approximately 2), while intensely calcitized basalt has a 20 times higher content of la than chondrites w ith a gentle negative inclination of the curve (ce/yb approxi­ mate[y 2). samples nj-s and 35 have weakly expressed ti / 100 dr--'.'-~ a c zr y x 3 fig. 8 three-component ti/ioo -zryx3 diagram for basalts (pearce & cann, 1973). lcgcnd: a) is land-a rc tholeiites (iat); b) middle-oceanic rift basalts (morb) and iat; c) calci­ um-alkalic basalts (ca b); d) within-platc basalts (wpi3). belak. halamic, marchig & tibljas: upper cretaceous palaeogene tholeii tic basn lts ... 171 nb x 2 fig. 9 three-component nbx2-zr/4y diagram for basalts (mes­ chede. (986). legend: ai) wi thi n-plate a lka li basalt s; all ) wi thin -platc basa lts and wi thin -platc tho le iites; b) e-type morb: c) within-p late and volcanic-arc basalts: d) niype mar 13 and volcanic-arc basalts. negative ell anomaly (eli/eli* = 0.79 and 0.7 1, respec­ tively; eli/eli * = eli ni'j(s mnx gdn), and sample 74 a weakly expressed posit ive eu anomaly (eli/eli* = 1.19). negat ive ell anomaly may indicate existence of the "magma chamber" where cumulat.e gabbroid rocks wilh pos itive eu anomaly were form ed. samples with a sli ­ ght negative eu anomaly may have fractionall y crystal ­ lized plagioclase or may have been in equi librium with plagioclase-bearing mant le source (wilson, 1989). a geochem ical model of ree normalized on chondrite is comparable to conti nental tholeiites. pamic et al. ( 1988) have performed isotopic deter­ mina ti ons of 180 and 87s r/86sr on several basalt sam­ ples, and pamic (1993) has determined the k-ar age on three samples of fresh basal ts (table 4). th e "s /" s .. d' h . r r ra tio 111 lcates t at basalti c magmas wcre formed by partial melting of upper mantle rocks (ta y­ lor & sl-ieppard , 1986). discrimination diagrams la ce pr nd sm eu gd tb dy ho er tm vb lu fig. ii diagram of the rare -earth elements llom1tllizcd on cho ndrite. ~o~----~------~-----,------~----, 20 10 v • • ti i 1000 • • • • 50 100 25 fig. 10 diagram ti/ 1ooov fo r basalts (s hervais, 1982). legend: t i/v ratios between 10 and 20: island-arc b .. lsa lts; ti/v rat ios between 20 and 50: morb, cont inental fl ood basalts and back­ arc basalts; ti/y ratios between 15 and 50 with a nca r-vertical trend: calc-alkaline basalts. "s r/"sr sio, and ba/y "sr /"sr (mantov ani et ai., 1985) also indicate that basalts of the pozeska gora ml belong to t.he high-t itanium tholeii tic volcanic seri­ es with a magmatic origin in enriched mantle. differen­ ces in oxygen isotopic compositi on argue that the ba­ salts were affec ted by postmagmatic , hydrothermal metamorphism of the oceanic iloor (s pooner et a i. , 1974; coleman, 1977). 6. discussion and conclusion pozcska gora ml. is mostl y composed of altered basalts and altered diabases, with subordinate fresh basa lts, diabases, gabbrodi abases, volcanic agg lome­ rat.es and tuffs . normative composit ion and petrochemi­ cal characteristics of major c lements, ttace clement s, and rare earth elements (ree) toge the r with the iso­ topic compos ition indi cate that the ana lysed rocks belong to the high-titanium tholeiit ic basa lt s, the mag­ ma for which originated fro m the upper mantle. rocks wcre affec ted by hydrothermal metamorphi sm , as indi­ cated by mineral parageneses and isotopes; there fore in approximately 80% of analysed rocks basic plagioclase is completely substituted by alb ite, and in ot hers pal1ial rock 01~o n sr flhisr k-ar-ages (ma) fresh basalt 5.3 o.70570± 16 altered basalt 7.3 0.70403±250 altered basalt 6.3 o.70435± 5 additional 3 samples 66.0±3.9 of basalts 54.5±2.7 48 ± 1.5 table 4 0180 content, sis r / 86sr ratio and k-a r ages. i72 albit izat ion is present. the secondary mineral paragene­ sis acco rding to erzinger (1989) belongs to the type iii: high-temperature (> 200°c) sea water­ basalt alteration at reducing conditions and medium to low water/rock ratios. however, it shou ld be pointed qut that secondary minerals albite, chlorite, epidote, prchnitc, sericite, pumpellyite and zeolite are also typ i­ cal for the very low degree of regional metamorphism (winkler, 1979). gathered k-ar ages of basic rocks from the pozeska gom mt. rangc from 66-48 ma (from the upper creta­ ccous/palaeocene boundary to the middle eocene) (pamic, 1993). the posi tion of the magmatic body is presen ted on the geolog ical map (fig. 2); it is dis­ cernible that veins of basic rocks cut the upper creta­ ceotls granite-rhyo li te complex, as well as upper creta­ ceous clast ic rocks. ful1hennore, within the basalt body numcrous decimelre-metre size outcrops of pelagic limestones and shales occur (fig. 3), and some of these were de termined as being of upper cre taceous age (uppcr santonian to lower maastrichtian pamic & sparfca, 1983). these rocks show no signs of more intense contact-metamorphic changes, except recrystal­ lization, probably because of the more abrupt cooling of lava dur ing submari ne effusion. s ince contact planes between basalts and sediments arc sharp , without load casts, it may be supposed that these sediment s were enclavcd aftcr lithification. however, the poss ibility that some sedimentary rocks represent layers between two eltusional events , cannot be excluded. on the basis of aforementioned, compatible geo logical and isotopic data, we may conclude that the basic rocks of the pozeska gora mt. are of upper cretaceous palaeogene age, and that they arc younger than the graniterhyolite complex and upper cretaceous clastic rocks. subduction processes during the early cretaceous, together with the eoalpi ne orogenesis (belak et ai. , 1995) had caused cmersion in the marginal part of the nort hern dinaridcs; therefore in this area there are no deposits of this age. subduction was e ithe r minimized during the uppe r cretaceous, or was completed, i.c. thcre was a closure of tethys in th is part of the dinar­ ides. postsubd uction tectonic processes (continen tal rifting or pseudorifting) have caused rhyolite volcanism along deep faults. rift ing or pscudorifting-extensional processes caused the upper cretaceous transg ression, which was registered in all marginal parts of the dina­ rides (sparica et ai., 1980), and formation of the uppcr crctaceous palaeogene marginal basin. basic rocks of thc pozeska gora mi. are, therefore, a consequence of cxtensional processes during the upper cretaceous and palaeogene along the northern margin of the dinarides. on the basis of geologica l and iso­ topic data it may be concluded that the first process was effusion of the rhyolites, and crystalliza tion of smallcr masses of its iillrusive equivalents. rhyolite magma was formed by partial melting of the continenta l crus t (pamfc ct a i. , 1990). partial melting, which produced acid crustal magma, was faeilitatcd by positioning o f geologia croatica 5 1/2 high-temperature basic magma in higher levels of the lithosphere (suneson & lucchitta , 1983). simi ­ lar geodynamicaj evoluti on o f some areas in the west­ ern part of the usa, resulting in bimodal volcanic asso­ ciation , was proposed by lipman (1980). by the upper cretaceous bas ic volcanism occurred in deeper parts of the already form ed basin, and las ted until the c losure of the basin (pyrenean tectoni c phase in the eocene) . in the geodynam ic inte rpretation of these areas it should be stated that rhyolites were placed along the marginal parts of the upper cretaceous­ palaeogene basi n, si nce they were not genetically relat­ ed to the sediment s in this basin , while basalts were placed in the deeper parts of the basin. consequent ly, acid and basic volcanic rocks were, during effu sion , spatially separatcd, and were posit ioned in their present mutual position by tangential tectonic transport during the tertiary. acknowledgements t he authors are indebted to dr. 1. pamic for the critical reading and improvement of the manuscript. we also thank dr. v. majer and dr. p. arkai for their thoughtful rev iews and useful comments. 7. references baric, lj. & tajder, m. (1942): petrografsko prou­ cavanje pozeske gore (pre thodni izvjcstaj ).yjest­ nik hrv. drz. gco!. zavoda i hrv. drz . geo!. muzeja, 1,22-26, zagreb. belak, m., pam ic, j., kolar-jurkovsek, t ., peckay, z. & karan, d. (1995): alpinski regi­ onalnometamorfni kompleks medvednice.1st cro­ atian geological congress, opatija, proceedings, 1, 67 -70, zagreb. cabanis, b. & leccolle, m. (1989): le diagra­ mme la/io y/15 nb/8: un outil pour la discrimi­ nat ion des series volcan iques et la mise en evidcl'tce des processus de melange ello u de co nt aminati on crusta lc.c.r. acad. sci. sel ii , 309, 2023-2029. ca rbonin, s. & molin, g. (j 980): crystal-chcmi­ cal considerat ions on e ight metamorphic epidotes.­ neues jahrbuch miner. abh., 139/2,205-215. erzinger, j. (j 989): chem ical alteration of the oce­ anic crust.gcol. rundschau, 78/3, 73 1-740. haas , j., csaszar, g., kovacs, s. & voros, a. (j990): evolution of the western part of the tethys as reflected by geological formations of hungary. ­ acta geod. gcoph. mont. hung., 25/3-4, 325-344. halam ic, 1. , belak, m. & jam icic, d. (1990): gcolosko-petrografski prikaz bazicnih stijena poze­ ske gore (slavonija/hrvatska).zbornik rad ova xiii kongr. geol. jugos l. , ii , 456-465 , ohrid. belak. halamic. marchig & tibljas : upper cretaceuus palaeogene tholeiitic 8asalts... 173 herak, m., jamicic, d., simunic, a. & bukosouthern part of the pannonian basin, yugoslavia.vac, j. (1990): the northern boundary of the acta geologica, 18/2, 13-39, zagreb. dinarides.aeta geologica, 20, 5-27, zagreb. koch, f. (19 17): prilog geoloskom poznavanju poze­ ske gore.foldtani intozct (1916) evi jelentesebol, 702-712, budapes t. koch, f. (1919): grundlinien der geologie von west­ siavonien.glasnik hrv. prir. drustva , xxxi/i-4, 217-236, zagreb. kov acs, s., csaszar, g., galacz, a., haas, j. , nag y, e. & voros, a. (1989): the tisza supcrunit was originally part of the north tethyan (european) margin.mcmoires de la soc. geol. de france, 4,81100. lipman , p.w. (1980): cenozoic volcanism in the wcstern united states: implications for continental tectonics.re print from "s tudi es in geophysics: con tinental tectonics", usa acad . sci., 161174, washington. majer, v. & tajder, m. (1982): osnovne karakte­ ristike spilit -kc ratofirnog magmatizma slavonije.­ acta geol., 12/1 , 1-22, zagreb. mantovani, m.s.m., marques, l.s., desou­ sa, m.a., civetta, l., atalla, l. & inno­ centi, f. (1985): trace element and strontium iso­ tope constraints on the origin and evolution of pa­ rana co ntinental f lood basalts of santa catarina statc (southern brazil).j. petrol., 26, 187-209. meschede, m. (1986): a method of discriminating between different types of mid-ocean ridge basalts and continental tholeiites with the nb zr y dia­ gram.chern. geol., 56, 207-2 18. newman, a.c.d. & brown, g. (1987): the chemi­ ca l const itution of clays.in: newman, a.c.d. (cd): chem istry of clays and clay minerals. miner­ alogical society monograph, 6, 1-128. nieto, f. (1997): chemical composition of meta­ pelitic chlorites: x-ray diffraction and optical prop­ erty approach. european 10urnal of mincralogy, 9, 829-841. pamic, j. (1988): mladoalpinski alkalijsko-fcldspatski graniti (a ljaskiti) pozcske gore u slavoniji.geolo­ gija,30, 183-205, ljubljana. pamic, j. (1993): late cretaccous volcanic rocks from some oil we lls in the drava depress ion and adjacent mountai ns of the sou the rn parts of the pannonian basin (north croatia).nana, 44, 203-2 10, zagreb. pamic, j. & sparica, m. ( 1983): staros t vulkanila pozcske gore.rad jazu, 404/19, 183-198 , za­ greb. pamic, j., lanphere, m. & mckee, e. (1988) : radiometric ages or metamorphic an d associated igneous rocks of the slavonian mountains in the pamic, j., injuk, j. & jaksic, m. (1990): prilog geokemijskom poznavanju gornjokredne bimodalne vulkanske asocijacije pozeske gore u slavonij i (sje­ verna hrvatska, jugoslavija).gcologija, 31-32, 415 -435, ljubljana. pearce, j.a. (1983): the ro lc of sub-continental l ithosphere in magma genesis at destructive pl ate margins. in: hawkesworth, c.j. & norry , mj . (cds): continental basal t and mantle xenoliths. nantwieh, shiva, 230-249. pearce, j.a. & cann, j.r. (1973): tectonic setting of basic volcan ic rocks determi ned using trace cle­ ment analyses.earth and plan . sci . letters, 19, 290-300. shervais, j.w. (1982): ti -v plots and the petroge­ nesis or modc rn and ophiolitic lavas. earth and planet. sci. letters, 59, 203-212. spooner, e.t.c., becki nsale, r.d., fyfe, w .s. & smewing, j.d. (1974): 180 enriched ophiolitic me tabasic rocks from e. liguria (ttaly), pindos (greece), and troodos (cyprus).contrib. mincral. pctrol. , 47,41-62. streckeisen, a. (1967): classification and nomen­ clature of igneous rock.neues 1ahrb.miner. abh., 107/2-3, 144-240. streckeisen, a. (1978): classification and nomen­ clature of volcanic rocks, lamprophyres, carbona­ tites and mel iii tic rocks.neues 1ahrb. abh ., 134, 114. suneson, n.h. & lucchitta, 1. ( 1983): origin of bimodal volcanism, southern basin and range pro­ vince, west-central arizona.geol. soc. amer. bull., 94,1005-1019. sikic, k. (1995) : prikaz geoloske grade medvedniee.­ in: sikic, k. (ed.) : geoloski vodic mcdvcdnicc, 730, zagreb. sparica, m., jurisa , m. , crnko, j., simunic, a., jovanovic , c. & zivanovic, d. (1979): osnovna geoloska karta sfrj i: 100.000. li st nova kapela l33-1 08.inst. za geol. istraz. zagreb, geol. zavod sarajevo (1966-1972), say. gcol. zavod, beo­ grad . sparica, m., j uri sa, m., crnko, j., simunic, a., jovanovic, c. & ziv anovic , d. (1980): osnovna gcoloska karta sfrj 1: 100.000. tumac za li st nova kapela l33-108 (geology of the nova kapc la sheet). ins!. za geol. istraz. zagrcb, sav. gcol. zavod, beograd, 55 p. tajder, m. (1947): albitski dolcrit iz nakop potoka u pozcskoj gori. geol. vjesnik, i, 182-189. tajder, m. ( 1955): istrazivanja papuka i poieske gore.ljetopi s jazu , 60, 307-308, zagreb. 174 t ajder; m: (1959): petrografsko proueavanje poie­ ske gore.ljetopis jazu, 63, 383-387, zagreb. taksic, a. (1944): 0 tektonici i morfologiji iztoenog dicla poieske gore (prethodni izvjestaj).vjestnik hrv. drz.. geo!. zavada i hrv. drz. geo!. muzcja, ii/iil, 28-36, zagreb. taylor, h.p. & shepard, s.m.f. (1986): igneous rocks: processes of isotopic fractionation system at­ ics. in: valleg, j.w., taylor, h.p. & o'ne­ il, j.r. (cds.): stable isotopes.miner. soc. amer., 16,227-272. thompson, r.n. (1982): magmatism of the british tert iary volcanic province.scott. j. geol., 18,49107. geologia croalica 5 [/2 tucan, f. (1919): sitan prinos poznavanju krista li­ nicnog kamenja pozeske gore.glasnik hrv. priro­ dosl. drustva, xxxi/l-4, 98-105, zagreb. wilson, m. (1989): igneous petrogenesis a global tectonic approach.unwin hyman, london, 455 p. winchester, j.a. & floyd, p.h. (1977): geoche­ mical discrimination of different magma series and their differentiation products using immobile e le­ ments.chem. geol., 20, 325-343. winkler, h.g.f. (1979): petrogenesis of metamor­ phic rocks.springer verlag, berlin, 348 p. manuscript received march 10, 1997. rev ised manuscript accepted november 23, 1998. 87velić plate xiii 88 geologia croatica 60/1 plate xiv 1–4 praeorbitolina wienandsi schroeder, early aptian; 2 – embryonic area – detail from fig. 1; 1–3: ogulin area, 4: dinara mt., croatia. 5 transitional form between praeorbitolina wienandsi schroeder and mesorbitolina lotzei schroeder, early aptian; ogulin area, croatia. 6–9 mesorbitolina lotzei schroeder, early aptian; 6: dinara mt., 7–9: ogulin area, croatia. 10 transitional form between mesorbitolina lotzei schroeder and mesorbitolina parva douglass transitional beds early–late aptian, jajce area, bosnia and herzegovina. 11–13 mesorbitolina parva douglass, late aptian–early albian; 11–13: ogulin area, croatia. 14 mesorbitolina parva douglass – mesorbitolina texana (roemer), late aptian–early albian; ogulin area, croatia. scale bars – 1, 13: 0.5 mm, 2, 6–7, 9: 0.1mm, 3–5, 8, 10–12, 14: 0.2 mm. 89velić plate xiv 90 geologia croatica 60/1 plate xv 1–5 mesorbitolina texana (roemer), late aptian–early albian; 1, 3–5: jajce area, bosnia and herzegovina, 2: ogulin area, croatia. scale bars – 0.2 mm. 91velić plate xv 92 geologia croatica 60/1 plate xvi 1–2 transitional forms between mesorbitolina texana (roemer) and mesorbitolina subconcava leymerie; early albian, ogulin area, croatia. 3–8 mesorbitolina subconcava leymerie, early albian; 3–6: ogulin area, croatia, 7–8: banja luka area, bosnia and herzegovina. scale bars – 1–7: 0.2 mm, 8: 0.5 mm. 93velić plate xvi 94 geologia croatica 60/1 plate xvii 1–4 “valdanchella” dercourti decrouez & moullade, late albian; 1–2: island of korčula, 3: dinara mt., 4: island of veli brijun, croatia. 5–7 neoiraquia convexa danilova, late albian; megalosphaeric forms, 5–6: dubrovnik area, 7: biokovo mt., croatia. scale bars – 0.2 mm. 95velić plate xvii 96 geologia croatica 60/1 plate xviii 1–4 neoiraquia convexa danilova, late albian; 1 – megalosphaeric form, 2–4 – microsphaeric forms; biokovo mt., croatia. scale bars – 1: 0.1 mm, 2–4: 0.5 mm. 97velić plate xviii 98 geologia croatica 60/1 plate xix 1–5 conicorbitolina conica (d’archiac), early–middle cenomanian; 1, 3–5: ogulin area, 2: istria, croatia. scale bars – 1–4: 0.2 mm, 5: 0.5 mm. 99velić plate xix 100 geologia croatica 60/1 plate xx 1–4 conicorbitolina cuvillieri (moullade), early–middle cenomanian, ogulin area, croatia. 5–8 chrysalidina gradata d’orbigny, middle–late cenomanian; 5–6, 8: istria, 7: unešić, croatia. scale bars – 1, 4, 6–7: 0.5 mm, 2–3, 5, 8: 0.2 mm. 101velić plate xx 102 geologia croatica 60/1 plate xxi 1–5 pastrikella balcanica cherchi, radoičić & schroeder, middle–late cenomanian; 1: glamoč area, bosnia and herzegovina, 2: unešić, 3, 5: istria, 4: ogulin area, croatia. 6–9 vidalina radoicicae cherchi & schroeder, 1985, late cenomanian; 6: istria, 7: unešić, 8–9: biokovo mt., croatia. scale bars – 1–5: 0.2 mm, 6–9: 0.1 mm. 103velić plate xxi 104 geologia croatica 60/1 plate xxii 1–4 pseudocyclammina sphaeroidea gendrot, upper turonian–coniacian, biokovo mt., croatia. 5–10 scandonea samnitica de castro, coniacian–santonian; 5–8, 10: biokovo mt., croatia, 9: jajce area, bosnia and herzegovina. scale bars – 1–4: 0.1 mm, 5–10: 0.2 mm. 105velić plate xxii 106 geologia croatica 60/1 plate xxiii 1–4 dicyclina schlumbergeri munier-chalmas, santonian–campanian; 1–2: jajce area, bosnia and herzegovina, 3: ogulin area, 4: biokovo mt., croatia. 5–10 murgella lata luperto sinni; late santonian; 5: unešić, 6, 10: bunić, croatia, 7–9: jajce area, bosnia and herzegovina. scale bars – 1, 3, 5, 7–9: 0.5 mm, 2: 1.0 mm, 4, 6, 10: 0.2 mm. 107velić plate xxiii 108 geologia croatica 60/1 plate xxiv 1–5 keramosphaerina tergestina stache, late santonian; 1, 4: jajce area, bosnia and herzegovina, 2–3: biokovo mt., 5: mosor mt., croatia. scale bars – 1, 4: 2 mm, 2, 5: 5 mm, 3: 1 mm. 109velić plate xxiv 110 geologia croatica 60/1 plate xxv 1–4 calveziconus lecalvezae caus & cornella, campanian; 1: jajce area, bosnia and herzegovina, 2–4: biokovo mt., croatia. 5–8, 10 murciella cuvillieri fourcade, early maastrichtian; makarska, croatia. 9 murciella cuvillieri fourcade and cuneolina ketini inan, maastrichtian; makarska, croatia. scale bars – 0.2 mm 111velić plate xxv 112 geologia croatica 60/1 plate xxvi 1–7 rhapydionina liburnica (stache), maastrichtian; 1–6 – megalosphaeric forms, 7 – microsphaeric form; 1, 4–6: konavle, 2: island of brač, 3: velika kapela mt., croatia, 7: divača area, slovenia. 8–13 fleuryana adriatica de castro, drobne & gušić, maastrichtian; 8–12: divača area, slovenia, 13: makarska, croatia. scale bars – 1–6: 0.2 mm, 7: 1.0 mm, 8–13: 0.1 mm. 113velić plate xxvi 114 geologia croatica 60/1 02-urumovic.indd 17 � ab stra ct verifi cation of recharge of groundwater in the deep quaternary sand layers covered with leaky deposits of silt and clay has been implemented using mathematical modelling of the aquifer system in conditions of test pumping and during the 10 year exploitation of the osijek well fi eld vinogradi. an analytical method for the identifi cation of local parameters of the leaky aquifer is shown using the excel program that enables usage of data from the relatively short term testing period, while at the same time suppressing external impacts. boundary conditions and regional aquifer parameters have been verifi ed by a numeric aquifer model, calibrated on the basis of three years of data from functioning fi eld wells. the 96 mm average yearly recharge of rainfall infi ltration into the aquitard was identifi ed by validation of the model, based on information obtained from observation of groundwater levels in piezometers and in the pumped wells over a ten year period. at the end of the validation period, there was a 20 month break in pumping of the entire well fi eld, and the measured recovery of groundwater levels provided an additional check on the results. variation in the groundwater levels from particular layers, and water quality during exploitation are explained by the combined effects of closing of some of the well screens and the heterogeneity of the aquifer system. keywords: groundwater recharge, groundwater modelling, leakage, aquifer, aquitard, well fi eld, groundwater quality impact of rainfall infi ltration on groundwater recharge of a deep quaternary aquifer � kosta urumović, željko duić and branko hlevnjak faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, 10000 zagreb, croatia; (kosta.urumovic@rgn.hr; zeljko.duic@rgn.hr; branko.hlevnjak@rgn.hr) doi: 104154/gc.2011.02 geologia croatica 64/1 17–30 19 figs. 3 tabs. zagreb 2011 geologia croaticageologia croatica 1. introduction there are two main reasons for emerging interest in water leakage to deep aquifers. one is linked to groundwater recharge and the long term prognosis of groundwater behaviour under conditions of intense exploitation for public water supply and irrigation. the other is linked to issues relating to the fi ltering of current and potential pollutants into deep aquifers. many different techniques of quantifi cation of groun dwater recharge and periods of retention are being used to signifi cantly reduce the uncertainty in some evaluations (scalon et al., 2002; healy & cook, 2002). ne vertheless, the most reliable methods are based on usage of data obtained from long term measurement of groundwater levels, because they show the effects of actual groundwater recharge. research on, and measurement of the activation and the fi rst ten years of production of the new water supply for the city of osijek, from the vinogradi well fi eld, is one such documented example. in the north-eastern parts of the republic of croatia, groundwater supplies occur in aquifers of the quaternary basins. the main issues in identifi cation of supplies and protection of groundwater are linked to quantifi cation of rainfall geologia croatica 64/1geologia croatica 18 infi ltration into the shallow aquifers, and leakage through layers of silt and clay. this is also the main topic of research into the exploitation and vulnerability of aquifers throughout the region of slavonia, and also in other regions of the pannonian basin. identifi cation of the boundary conditions and parameters, as well as verifi cation of groundwater replenishment in the osijek well fi eld vinogradi are especially interesting. the fi eld is located about ten kilometres from the city itself. the captured aquifer emerges in quaternary layers consisting of sand, with intercalations of silt and clay. there are 18 wells in the vinogradi well fi eld (w1-w18), 200 m apart (fig.1) that capture sand layers at depths of 40−170 m (fig. 2). detailed research was carried out prior to well fi eld construction and activation at the end of july 1984. ten years later, the well fi eld was shut down for 20 months during pipeline reconstruction connecting it to the water processing and supply station 8km away. data pertaining to the behaviour of groundwater during these periods enabled verifi cation of groundwater recharge of the aquifer, groundwater behaviour and identifi cation of the qualities of the leaky layers. 2. geological structure of the aquifer superfi cially, the geological structure is very simple, both chronostratigraphically (composed of the latest holocene and the latest pleistocene), and lithologically (because of an admixture or alternations of sand, silt and clay layers). nevertheless, there are systematic differences both in mor phology and lithostratigraphy that increase with depth. also lithologic differentiation of the latest layers shows notable re fl ections of deep structures. a lithological profi le of the quaternary layers was explored on the basis of data from research drilling. the shallower parts were examined by wells drilled for exploratory and water capture purposes as part of the hydrogeological research, while the deeper parts were explored as part of oil related geological research. analysing the data collected from boreholes throughout the northern region of croatia, urumovic et al. (1976) note two contrasting levels in the otherwise general alternation of fi ne and coarse clastic quaternary sediments. the boundary between the two is labelled as a conditional marker q’. the upper layers above this marker are characterised by their unconsolidated material, relatively high proportion of permeable coarse clastic layers and quantity of fresh water quantity. below the q’ marker, consolidation is higher, the proportion of permeable, coarse clustered layers is smaller and there are signifi cant differences in the mineral composition of waters from different layers both vertically and horizontally. water mineralisation is generally higher in these layers in comparison to the upper layers. the layers above the q’ marker (urumović et al., 1976, 1978) are dated as being of mid – late pleistocene, holocene ages, while those below the marker are dated as being of lower pleistocene and plio–pleistocene age. the fact that above the q’ marker there is a sequence of layers in which coarse clustered sediments are predominant leads to the conclusion that these are a result of regional changes in the properties of sedimentary material caused by change in palaeoclimatic conditions. in the middle of the quaternary layers above the q’ marker, there is another lithological horizon that resembles the q’ marker. it is marked as x in the regional correlation profi le (fig. 2). the coarsest sediments in the entire eastern region of the river drava depression (urumović, 1982) occur above this marker. immediately above this marker, singular, small gravel granules occur over most of this area. fi gu re 1: location of the osijek vinogradi well field and tested piezometers. urumović et al.: impact of rainfall infi ltration on groundwater recharge of a deep quaternary aquifer geologia croatica 19 the impression is that these layers are a consequence of a powerful widespread transgression when in baranja, in the inundated part of podunavlje; gravel layers 50 m thick were deposited. at this level, southeast of osijek, at 60 m depth, there are bored pebbles of gneiss granite that are 120 mm in diameter. the diameter of these pebbles is extraordinary for the area; however they have also appeared in many other boreholes. wireline log correlation confi rms the regional nature of their occurrence representing the coarsest sediment deposition in this area. coarse grained materials of the wider vinogradi well fi eld area are mostly represented by uniform small – medium sand grains 0.05 to 0.3 mm in size, of up to 85% quartz grains. the fi ne-grained sands contain a high proportion of micas. sometimes there is so much of it that the grains shine in the borehole core and appear much larger than they really are. the sands also contain fragments of carbonate rock; feldspars, amphibole, epidote and granite, suggesting that the original rocks were predominantly part of the alpine massif and to a lesser degree, the slavonian mountains. fine grained materials are represented by silt, sandy-silt, silty to fi ne clay. colouration ranges from gray, silver-blue to green. there are also concretions as fragments, angular to round in shape, usually light gray to green and greenishwhite in colour. while the layers of silt and clay are moist, concretions are usually dry because of suction, and in wireline logs they appear as a contrasting defl ection. the mineral composition is predominantly quartz, with subordinate micas and feldspars. in some parts there are considerable quantities of calcite, particularly among grains coarser than 0.06 mm, while montmorillonite forms >10% of the fi nest fraction. an important characteristic of the quaternary layer structure is the alternation of coarse and fi ne layers, evident at two scales. texturally, thin, almost millimetre alternations of silt and sand, are sometimes laminated and angled. these are notable where fi ne grained sand and silt layers are mostly present. in the thicker sand layers, some sedimentary cycles typically start with sand >0.2 mm grain size which then fi ne upwards, so granulometric parameters illustrate sedimentation cycles in almost every thicker layer. these lithological characteristics generate hydraulic anisotropy evident in laboratory testing and a general heterogeneity that may have effects of anisotropy. 3. analytical identification of hydrogeological parameters and boundary conditions at the vinogradi well fi eld, all exploitation wells have had screens installed into all layers of pure, uniform sands. this has practically excluded the effects of anisotropy on gro undwater fl ow, and in these conditions radial fl ow was horizontal, as it is the fl ow in a homogeneous and isotropic aquifer. the process of drawdown during well pumping under these conditions, shows recognisable effects of all the hydrogeological parameters of the aquifer, in accordance with the hantush theory of leaky aquifers (hantush, 1960). the effects of the parameters of the pumped layer are easily recognised, even at the very early stages of well pumping at constant discharge. estimation of the transmissivity and storage coeffi cient, by means of a derivative method using the early time drawdown (straface, 2009), can be derived even for t > r2s / 4t. longer pumping results in a widening cone of depression and the percolation effects begin to be in tegrated through aquitard leakage and are detected in diagrams showing time-drawdown. in practical terms, very long term pumping is often affected by external impacts. in such cases it is necessary to use data from the early phase of pumping that is dominated by the infl uence of pumping of the tested well. it was exactly this kind of diffi culty that arose in the interpretation of the test pumping of wells w-7 and w-15 at the vinogradi well fi eld that had been conducted prior to their connection to the water supply system. analytical identifi cation of boundary conditions and aquifer parameters used data from the graphic image of the groundwater level drawdown in the semi-log diagram of time-drawdown for all the measured wells (figs. 3 and 4). the non-stationary distribution of water level drawdown around the lone standing well pumping from the semi-confi gu re 2: cross-section of the quaternary layers of the vinogradi well fi eld. geologia croatica 64/1geologia croatica 20 fi ned aquifer can be described as a relatively simple hantush-jacob (1955) solution: s q e dx q t w u rx r x u = =e x          − −x ∞ ∫4 t 4∫ 2 24 π πx 4t x∫ λ λ , (1) where: w(u,r/λ) well function for leaky aquifers, u r s tt = 4 , s is drawdown, q is constant discharge of the well, t is transmissive coefficient, s is storage coefficient, λ = t b k, ,k/kkk is leakage factor, b’ and k’, are the thickness and hydraulic conductivity of the aquitard bed through which leakage occurs, r is the distance from the centre of the well to any point in the fi eld, and t is the time since pumping began. simplifi cation in formula (1) relates to the dismissal of elasticity effects of the leaky layer and the occurrence of source layer drainage. the latter may become very signifi cant in long term pumping, the simplifi cation is therefore more appropriate in the beginning of test pumping than in the fi nal phase. the slope of the theoretical drawdown curve s in relation to time t in semi-log scale shows hantush (1956) by derivation of equation (1) in relation to log t: δ π λs s t q t e u r u= = − −u∆ ∆ log .2 3. 4 2 24 (2) this applies to any point on the curve, and for a point of infl ection, the second derivative is equal to zero: ∂ ∂ = − ∂ ∂ + ∂ ∂           =− −2 2 4 2 2 2 4 6 4 0 2 2 s t tq e u r u u t u r u (log ) . π λ∂ 4 4∂ e t uλ (3) which is achieved when r u 2 2 2u4 1 0 λ −1 , so at the infl ection point u r r s tti i = = 2 4 2 λ (4) and the slope of the drawdown curve at the infl ection point results from the insertion of (4) into (2): δ π λs q t ei r= − 2 3 4 . / (5) where e–r/λ expresses how the effect of percolation through the aquitard bed is increasing by the distance from the pumped well. when λ→∞, er/λ = 1 the aquifer becomes confi ned and equation (5) turns into the well known cooperjacob (1946) equation. for the identifi cation aquifer system parameters on the basis of data from the beginning of the testing period, testing of at least two objects is required. if there is at least 50% of maximum drawdown, and this is achieved when t > rλs/2t the graphic-analytical (hantush, 1956) or the type curve (urumović, 1978) method may be used. however, nowadays it is more appropriate to use computer programmes such as ms excel that enables the elegant application of comparison of theoretical functions and experimental data. this proved very useful for identifi cation of the range of values of aquifer parameters and the effect of boundary conditions on the basis of test pumping data of the wells situated in the middle (w-7) and on the edge (w-15) of the vinogradi well fi eld (fig. 1). each test pumping lasted for 26 days. the fi rst occurred in autumn 1983, and the second in the winter of 1984. test pumping was done in the period of recession when the stabilization of the level on maximal drawdown was not expressed, nor was its tendency that could facilitate graphic extrapolation of maximum drawdown (figs. 3 and 4). however the effects of groundwater recharge are clear through the spatial distribution of the slope of the bi-log curve s(t) in some of the tested wells. when identifying real boundary conditions and the values of parameters, the slope of the drawdown curve is not directly conseidered but see the function: s t q i[ ]e r− =, . δ 0 183 (6) calculated for the slope reading δsi and the presumed t and λ. the related series of points are compared to the function fi gu re 3: semi-log plot of drawndown versus time in observation wells during testing of w-7. urumović et al.: impact of rainfall infi ltration on groundwater recharge of a deep quaternary aquifer geologia croatica 21 fi gu re 4: semi-log plot of drawndown versus time in observation wells during testing of w-15. fi gu re 5: semi-log graph of theo re ti cal functions and data of the test well w-7 (q=79 l/s, transmissivity t=1.05*10–2 m2/s, leakage factor λ=1500 m). graphs r/λ, exp(-r/λ) and exp(r/λ=0) (fig. 5 and 6). the last one is a horizontal line that represents the case of a non-leaky aquifer. in the procedure presented above, a trial method is used to identify values for the transmissivity and leakage factors, and a coefficient of storage according to equation (4), whereby time ti is read on the diagrams (fig. 3) for s q t ki = 4 0k π λ( /r λλ ) (7) where k0 is the modifi ed bessel function of the second kind and zero order. the performed procedure confi rms the boundary conditions for a leaky aquifer, identifi es values of the hydraulic parameters of the aquifer, and confi rms that during pumping of the tested wells, groundwater fl ow was the same as for a homogeneous aquifer. the method performed has two characteristics, the main one being based on the analytical solution of the continuity equation for the semiconfi ned aquifer. therefore the hydraulic homogeneity of the aquifer is assumed. the second characteristic is that it uses a technique of interpretation that is classed as a trial method, which is the implicit characteristic of all types of curves and the explicit characteristic of all numerical methods. 4. numerical modelling the investigation has been initiated under the assumption of a leaky aquifer as the general case of an artesian aquifer, and has been directed on recharge identifi cation. groundwater fl ow through such a system can be described by two partial differential equations, one for the aquifer and the other for the covering aquitard. for the aquifer: x ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ ( ) ∂ ∂ ( ) ∂ ∂ ( ) ∂ ∂ ' ' ( ' ) h x y∂ h y q s h t k b h'=)+ ( −( )s (8) where in (fig. 7): h(x,y,t) is the hydraulic head in the aquifer at time; t, h’(x,y,t) is the hydraulic head in the covering aquitard at time t; k equals the hydraulic conductivity of the main aquifer for horizontal fl ow; k’ is the covering aquitard’s hydraulic conductivity for vertical fl ow; b (x,y) is the thickness of the aquifer; b’ (x,y,t) represents the saturated thickness of the covering aquitard at time t; s(x,y) is the storage of the aquifer; and q(x,y,t) is the net rate of pumping at time t. the left side of eq. (8) represents the horizontal fl ow in the aquifer, the right side the vertical fl ow. geologia croatica 64/1geologia croatica 22 for the covering aquitard, there is a one-dimensional differential equation. assuming that the aquitard has a free water table, so that it’s saturated thickness b’ is not constant, but may vary with time. since both the water received from infi ltration, and the water released by a falling water table percolate through the aquitard before reaching the aquifer, the following equation applies: i n h t k m h hwi =n ' ' ' ( 'h ) ∂ ∂ (9) where iw is the net rate of infi ltration, and n’ is the specifi c yield of the covering aquitard. owing to its low permeability, and thin intercalated sand layers, we also assume that no pumping will occur in this layer. in equation (8), if the hydraulic conductivity of the aquitard k’=0, then (k’/b’)(h’-h)=0, and the aquifer is confi ned. in equation (9), if there is no infi ltration, iw=0, we have a decrease of aquitard water level as well as the piezometric level in the main aquifer (if q=const.) the fi nite difference method of approximating the solution of differential equations (8) and (9) is used. the mathematical model covers an area of 1410 km2 discrete nodal areas, networks of rectangles, squares and polygons 0.04–41 km2 (fig. 8). 4.1. boundary condition analysis and model calibration the fi rst three years of pumping are the most interesting in the whole process of recharge identifi cation. in this period, pumping rate was gradually increasing, and at the same time a decrease in piezometric level occurred. three cases have been analysed through calibration: a) confi ned aquifer (k’=0; – impermeable covering bed) b) semi confi ned aquifer (k’>0; iw=0 – permanent drainage of covering aquitard) c) semi confi ned aquifer (k’>0; iw= iw(x,y,t) – calibrated solution) the water level behaviour in all these cases is presented for four testing holes, and piezometers; pz-4 between pumping wells 14 and 15; pz-8 about 4400 m west of the well fi eld, pz-12 about 3300 m west of the well fi eld and pb-14 300 m east of well w-6 (fig. 1). divergence of the fi rst two curves confi rms leakage from the covering aquitard bed after at least a few months. in contrast, after a longer period of a few years, recharge of the aquitard becomes rather obvious (fig. 9). the effect of the value and the distribution of hydraulic conductivity and thickness of the aquifer in al three cases are fi gu re 6: semi-log graph of theoretic functions and data of the test well w-15 (q=62.5 l/s, transmissivity t=1.0*10-2 m2/s, leakage factor λ=1400 m). fi gu re 7: sketch of the hydraulic schematisation of the aquifer system. urumović et al.: impact of rainfall infi ltration on groundwater recharge of a deep quaternary aquifer geologia croatica 23 only predominant during the fi rst couple of days of pumping, when considerably more than 50% of drawdown in the exploitation wells takes place. later, the effect of drainage from the covering aquitard deposit slowly prevails, together with aquitard recharge through rainfall infi ltration. model calibration is therefore implemented for two discrete time periods. the fi rst step in model calibration simulated the behaviour of the water level during the fi rst two days of pumping, during which process the hydraulic conductivity and the aquifer storage capacity were checked in the well fi eld area considering the values determined at the test pumping. the medium hydraulic conductivity of the captured aquifer is from 1.4*10–4 to 2.0*10–4 m/s, and the vertical hydraulic conductivity of the covering leaky deposits is from 10–8 to 10–7 m/s. aquifer storage ranges from 5*10–4 to 2*10–3, and the average effective porosity of the aquitard deposit is from 0.03 to 0.16. in the second phase, simulation of the fl uctuation of water level in the fi rst 3.5 years of pumping of the vinogradi well fi eld was conducted (fig. 9). in this period of water level fl uctuation, the predominant infl uence comes from the porosity of the covering leaky layers and the water stored therein, together with the capacity of some wells and primarily the whole well fi eld, and from groundwater recharge by rainfall infi ltration into the aquitard deposit. rates of 80–170 mm total annual infi ltration to the aquitard water table have been identifi ed for this period (urumović et al., 1996). this represents 12–19% of the total annual precipitation, and these values compare well with agricultural investigation of the water balance at the adjacent bizovac experimental fi eld (tadić et al., 1994) and statistical correlation of precipitation and water level fl uctuations (urumović, 1982). 4.2. model validation numerical model validation of the aquifer system was primarily initiated by the occurrences of signifi cantly lower than speculated falling groundwater levels in some wells, (fig. 14) which could have been interpreted in different ways. an additional incentive for the validation was the data gathered during the 20 months interruption of pumping due to reconstruction of the pipelines between the well fi eld and the water processing facility. during that time, the water level in the wells rose to a height only 0.5 m lower than the level registered before the beginning of pumping (table 2), and in some distant piezometers it rose above the initial height (table 1). these observations, as well as a lot of data gathered during groundwater monitoring at the vinogradi well fi eld proved challenging for the exact mathematical verifi cation of possible causes of the registered state of groundwater before and after the interruption of pumping. the research was primarily focussed on groundwater recharge of the deep aquifer layers, and therefore as part of the validation of previously calibrated models, attention was on the manifestations of groundwater level fl uctuation in pumped wells and observed piezometers during the 10-year period analysed. prior analysis of boundary conditions illustrated the aquifer inertia in the process of drainage of the covering aquitard deposit (fig. 9). this is expressed by a strong reduction in drawdown in the captured aquifer as a consequence of water leaking from the aquitard deposit, and in the case when there is no recharge by infi ltration of rainfall, (fig. 9, case k’>0, iw=0). in such conditions the effect of rainfall infi ltration is completely suppressed by the effects of the pumping regime of some wells and the whole well fi eld. the effects fi gu re 8: graded network superimposed on the arrangement of pumping wells and piezometers. geologia croatica 64/1geologia croatica 24 of recharge are clearly visible only in very distant observed piezometers where vertical water balance components become dominant and the groundwater fl uctuation primarily expresses the local manifestation of the vertical water balance. for long term, regionally signifi cant trends mean annual rainfall has a dominant effect and its infl uence is often carried over into the next year. in this case it turned out to be a good outcome, as there were intervals of poor water level measurement in the 10-year observation span, especially during the war in 1991 and 1992. the main idea behind validation of the mathematical model of the aquifer system was measurement of the water level in piezometers with screens installed in most of the aquifer layers of the captured aquifer (fig. 10 to 13). the accuracy of simulated water level fl uctuations for the aquifer under groundwater recharge of the source aquitard layer, where infi ltration of 48 to 180 mm annually was equally distributed in 12 monthly increments, has been checked. the best match of the measured data and the simulated curve (fig. 10 to 13) occurs where constant recharge of aquitard water is from 8 mm per month, or 96 mm/year. it can therefore be concluded that the water level fl uctuation in the area infl uenced by the well fi eld is primarily conditioned by the pumping regime (fig.15), and the long term trend is driven by the capacity of the average recharge of the aquifer system. the results of identical simulations for some of the pumping wells are shown in figs. 14 & 15. at the start, these graphs show a good match between the calculated water levels and the control measurements. in the later period there is a divergent sequence of data. water levels in pumping wells start to diverge from the simulated sequence as soon as the pumping is stopped, when the water level rises up to that of the simulated curve. after pumping of all wells ceased with disconnection from the water supply system, the water level suddenly rises to the approximate level in the nearby piezometers and gradually reaches the initial level recorded before the start of pumping (fig. 10–15 , table, 1–2). the simulated 10-year period fi nished at the end of may 1994, 13 months after pumping was stopped. the average annual rainfall recorded for the period at a rain station near osijek, 10 kilometres east of the well fi eld was 620 mm per annum, excluding 1991 and 1992 when data was incomplete (table 3). this amount is around 5% below the 30-year average. as the average rainfall amount gradually rises westwards (with an average gradient of round 2 mm/km), it can be estimated that the amount of calculated water recharge in the aquitard deposit by rainfall infi ltration was around 14%–15% of the average annual rainfall. this amount is well within the range from earlier prognosis and research of this area. considering that the validation was made on the basis of data on the effects of a relatively strong long term pumping regime, there are important factors that give these values regional signifi cance. 5. the impact of aquifer anisotropy on groundwater levels and quality the mechanism of groundwater behaviour within the aquifer system was recorded in nested piezometers that all had fi gu re 9: results of simulated groundwater levels in the model calibration process. urumović et al.: impact of rainfall infi ltration on groundwater recharge of a deep quaternary aquifer geologia croatica 25 fi gu re 10: simulated (s) and measured (m) groundwater heads in piezometers west of the well fi eld. fi gu re 11: simulated (s) and measured (m) groundwater heads in piezometers east of the well fi eld. fi gu re 12: simulated (s) and measured (m) groundwater heads in piezometers south of the well fi eld. geologia croatica 64/1geologia croatica 26 at least two piezometers, one with screens in all the major layers of the captured aquifer (pz-4 and pz-3, fig 17), and the other with an isolated screen at 24–27 m in the aquitard deposit (pz-4a and pz-3a, fig 17). data regarding groundwater levels in these piezometers were used in the process of calibration and validation of the mathematical model. nested piezometers that also measure groundwater level in specifi c sand layers, were placed near some of the pumping wells, in order to note the effects of heterogeneity and anisotropy on the groundwater level. therefore the nested piezometer pz-4, had an additional screen at 165–168 m for pz4/1, 102–105 m for pz-4/2, 69–72 m for pz-4/3 and 54–57 m for pz-4/4. the groundwater level in these is a little different at times of inactivity, but during pumping, it was only at the same level for the fi rst 30 months (till the end of february 1987, fig. 16). after this period, there was a strong divergence in groundwater level in some piezometers. in a few the groundwater level dropped signifi cantly (pz-4/1), whereas it rose in others (pz-4/2, 4/4), so that the maximum difference in groundwater level in 1991 was round 15 m (fig. 16). at the same time the nearby wells w-14 and w-15 (fig. 14) experienced a sudden drop in water level during pumping and when they were closed off, the water level rose to the pre-pumping height. this drop in well capacity is a fi gu re 13: simulated (s) and measured (m) groundwater heads in piezometers in the north part of the well fi eld. fi gu re 14: simulated (s) and measured (m) groundwater heads in the pumping wells. urumović et al.: impact of rainfall infi ltration on groundwater recharge of a deep quaternary aquifer geologia croatica 27 consequence of the closure of some screens which happens to be a common occurrence in aquifers with higher levels of dissolved iron. the rate of aquifer system recovery after pumping ceased between april 1993 and november 1995 is illustrated in fig. 17. at the moment of pumping ceasation, the groundwater level in all layers of the captured aquifer rises above the groundwater level of the aquitard deposit (pz-4a) and therefore the immediate area of well fi eld experiences a temporary draining of the aquifer into the aquitard. groundwafi gu re 15: total capacity (σq) of the vinogradi well fi eld and water heads in well w-5. table 1: measured and simulated values of groundwater head in tested piezometers prior to and after the simulated period. pz-3 pz-4 pz-5 pz-6 s m s m s m s m initial 85.13 85.13 85.75 85.75 85.20 85.20 85.21 85.21 end 84.69 84.90 84.43 85.40 84.26 84.80 85.56 86.00 diff erence -0.44 -0.43 -1.32 -0.35 -0.94 -0.40 -0.65 -0.21 pz-8 pb-12 pb-14 pb-18 s m s m s m s m initial 86.20 86.20 85.05 85.05 85.13 85.13 84.95 84.95 end 86.70 86.50 83.96 84.50 83.91 84.30 83.75 83.90 diff erence +0.5 +0.30 -1.09 -0.55 -2.22 -0.83 -1.20 -1.05 table 2: measured and simulated value of water head in pumping wells before and at the end of simulated period. w1 w2 w3 w4 w5 s m s m s m s m s m initial 84.9 84.9 84.9 84.9 85.0 85.0 85.0 85.0 85.1 85.1 end 83.8 84.4 83.8 84.5 83.8 84.5 83.8 84.6 83.9 84.6 diff erence -1.1 -0.5 -1.1 -0.4 -1.2 -0.5 -1.2 -0.4 -1.2 -0.5 w6 w7 w8 w9 w10 s m s m s m s m s m initial 85.1 85.1 85.1 85.1 85.2 85.2 85.3 85.3 85.3 85.3 end 83.9 84.7 84.0 84.8 84.0 84.6 84.1 84.9 84.1 84.9 diff erence -1.2 -0.4 -1.1 -0.3 -1.2 -0.6 -1.2 -0.6 -1.2 -0.4 w11 w12 w13 w14 w15 s m s m s m s m s m initial 85.4 85.4 85.5 85.5 85.6 85.6 85.8 85.8 85.8 85.8 end 84.2 85.1 84.3 85.2 84.3 85.4 84.4 85.5 84.5 85.6 diff erence -1.2 -0.3 -1.2 -0.3 -1.3 -0.2 -1.4 -0.3 -1.3 -0.2 geologia croatica 64/1geologia croatica 28 ter exchange between the main aquifer and the aquitard hides the effects of rainfall infi ltration in the well fi eld area until the end of the break in pumping which further confi rms the results of the implemented simulation. these infl uences diminish with distance and at the location of the nested pyrometer pz-3 the amount of rainfall infi ltration half way thorugh the no pumping period exceeds the effects of water exchange with the main aquifer. chemical composition of groundwaters also reacts to the changes of the hydraulic resistance in the well casing. the quantity of common anions (hco3 –, so4 2–, cl–) remains almost unaltered, while the quantity of cations (ca2+ and mg2+) changes in such a manner that the quantity of calcium drops, while the quantity of magnesium stays the same (fig. 18). this could be ascribed to larger amounts of water from the deeper layers that have a higher content of sodium. still, the most signifi cant relative change is in the quantity of accessory components of iron and manganese (fig. 19). the changes of these components lead to the conclusion that the infl uence of iron utilising bacteria on the process of closing of the well screens is faster in layers that are richer in dissolved iron and manganese, and that larger amounts of water are pumped from layers with lower amounts of these components. therefore, the groundwater level drops rapidly in such layers, and rises in those that are less pumped. this results in a radical increase in the effect of heterogeneity and table 3: rainfall in osijek during the analysed period and the 30-year average. year i ii iii iv v vi vii viii ix x xi xii σ 1980. 31.7 47.3 36.7 92.5 100 76 58 65.7 15.7 51.3 116.1 53.4 744.4 1981. 58.2 33.7 96.2 28.2 22.3 180.2 28.3 49.6 64.7 90.9 47.1 117.7 817.1 1982. 14.6 15.6 46.2 71 30.6 59.4 79.5 97.4 23.1 26.1 32.7 83.6 579.8 1983. 28.1 39.8 27.2 19.6 62.3 67.2 42.5 32.4 100 20.3 10.6 16.9 466.9 1984. 99.9 33.9 36.5 54.7 89.9 73.7 37.4 36.2 50.3 51.1 40.5 19.7 623.8 1985. 45.8 51.9 49.7 56.3 32.6 119.5 29.7 88.2 8.8 9.6 105 21.6 618.7 1986. 67.2 79.3 43.3 38.3 42.1 57.8 40.7 60.6 6.9 60.4 16.1 23.6 536.3 1987. 97.2 6.2 54.3 59.9 170.6 77.6 33.4 27.4 18.3 23.7 112.8 37.6 719 1988. 35.4 41.6 116.4 39.7 43.6 96.3 29.4 14.6 58.4 30.7 28.7 30 564.8 1989. 6.4 9.2 48.3 46.1 106 83 63.7 95.6 35.7 48.6 42.2 18 603.1 1990. 11.8 39.4 25.8 38.4 26.2 101.4 38.7 42 72.3 33.7 52.7 58.5 540.9 1991. 28.6 30 37.3 78.8 102.1 26.4 119.2 89.2 40.8 552.4 1992. 13 59 39.7 112.4 42.3 18.9 36.4 155.3 105.1 50.2 632.3 1993. 22.7 8.9 61.6 42.6 47.7 69.5 55.2 56.7 58.8 43.1 95.5 92.5 654.8 1994. 45.4 31.7 34.8 52.4 34.6 88.2 19 83.6 120.3 57.5 16.1 45.1 628.7 1995. 70.9 52.7 44.5 52.2 96.4 105.5 26.7 85.6 123.2 5.8 53.6 104.4 821.5 mean 41.5 32.6 48.2 51.9 65.4 87.1 46.5 59.0 52.1 44.3 54.7 48.3 631.5 1961−1990 650.4 1971−2000 654.2 fi gu re 16: hydrograph of nested piezometers pz-4. urumović et al.: impact of rainfall infi ltration on groundwater recharge of a deep quaternary aquifer geologia croatica 29 anisotropy of aquifer, which accentuates the importance of the casing design of wells and piezometers. it is interesting to note that the above described effects of anisotropy disappear after the 20-month break in pumping, and reappear six moths after it is restarted (figs. 16, 18, & 19). 6. conclusion the effect of the infi ltration of rainfall on deep groundwater recharge can be precisely identifi ed only on the basis of data from long term pumping. in spite of this, boundary conditions that enable such identifi cation are detectable even from data collected during relatively short term experimental pumping of wells. drainage from leaky layers, (in the case of leaky aquifers), slows down the progress of water level drawdown round a pumped well. this occurs to the extent that on the basis of the spatial pattern of drawdown progressing as a function of the logarithm of time, all the hydraulic parameters needed for long term prognosis can be determined, even though drawdown through puming is only slightly higher than 50% of the maximum drawdown. the method of this kind of interpretation of experimental pumping has been demonstrated for the osijek, vinogradi well fi eld that captures a heterogeneous leaky aquifer. it is the heterogeneity of the layers themselves that cause the contrasting effects of pumping on the water level pattern within the captured aquifer and raise doubts about ground water recharge. it can be concluded that calibration and validation of the numerical mathematical model of the aquifer system have unquestionably confi rmed that the condition of the aquifer, controlled by the existing monitoring, can only be performed with effective groundwater recharging. as this verifi cation relates to a 10-year period where the average annual rainfall was 620 mm, (a quantity ~ 5% less than the 30-year average), the identifi ed mean annual aquifer recharge of 96 mm can be regarded as a regional example of similar hydrogeologic relations and climate conditions. groundwater is recharged by rainfall infi ltration and that process hides the effect of the particular rainfall. those particular rainfalls, when being integrated have some effect on trends, while main divergence in groundwater levels are caused by pumping regim of the whole well fi eld. the change in pumped quantity of water from some layers of the aquifer after the closure of some screens resulted in a change in the composition of calcium, sodium, iron, fi gu re 17: the relationship between the water level in the captured aquifer and the source aquitard layer during the cessation of pumping (pz-3a and pz-4a are piezometers with screens in the covering aquitard layer). fi gu re 18: primary cations and anions in water from well w-14. geologia croatica 64/1geologia croatica 30 manganese and possibly some other components in the water, which refl ects the diversity of the sedimentary conditions of the aquifer sands and the mechanism of groundwater recharge. this is an additional reason for the construction of appropriate nested piezometers in the development of ground water monitoring. acknowledgement we would like to thank the reviewers for their comments and suggestions that have improved this manuscript. this work was supported by ministry of science, education and sports of the republic of croatia, croatian waters and vodovod osijek. references boonstra, j. & ridder, n.a. (1981): numerical modeling of groundwater basins.− ilri, pub., 29, wageningen, 226 p. cooper, h.h.jr & jacob, c.e (1946): a generalized graphical method for evaluating formation constants and summarizing well-field history.− trans. amer. geophys. union, 27, 526−534. de vries, j.j. & simmers, i. (2002): groundwater recharge an overwiev of processes and challenges.− hydrogeology j., 10/1, 5−17. hantush, m.s. & jacob, c.e. (1955): non-steady radial fl ow in infi nite leaky aquifers.− trans. amer. geophys. union, 36, 95−100. hantush, m.s. (1956): analysis of data from pumping tests in leaky aquifers.− trans. amer. geophys. union, 37, 702−714. hantush, m.s. (1960): modifi cation of the theory of leaky aquifers.− j. geophys. res., 65, 3713−3725. fi gu re 19: amount of fe and mn in the water at well w-14. healy, r.w. & cook, p.g. (2002): using groundwater levels to estimate recharge.− hydrogeology j., 10/1, 91−109. scalon, b.r., healy, r.w. & cook, p.g. (2002): choosing appropriate techniques for quantifying groundwater recharge.− hydrogeology j., 10/1, 18−39. straface, s. (2009): estimation transmissivity an storage coeffi cient by means of a derivative method using the early time drawdown.− hydrogeol j., 17/7, 1679−1686. tadic, z., urumovic, k., tadic, l. & geres, d. (1994): sustainable groundwater use. xviith conference of the danube countries on hydrological forecasting and hydrological bases of water management.− proceedings, budapest, 493−497. toth, j. (1995): hydraulic continuity in large sedimentary basins.− hydrogeology j., 3/4, 4−16. urumović, k. (1978): graphic method of determination of the leaky aquifer by the standard distance-slope curve. symposium on investigation and economy of the underground waters.− working papers, b, zagreb, 23−30. urumović, k. (1982): hidrogeološke značajke istočnog dijela dravske potoline.− unpubl. phd thesis, university of belgrad, 138 p. urumović, k., hernitz, z. & šimon, j. (1978): o kvartarnim naslagama istočne posavine (sr hrvatska).− geol. vjesnik, 30/1, zagreb, 297−304. urumović, k., hernitz, z., šimon, j. & velić, j. (1976): o propusnom mediju kvartarnih, te gornjoi srednjo-pliocenskih naslaga sjeverne hrvatske.− iv jug. simp. o hidrogeol. i inž. geol., 2, skopje, 395−410. urumović, k., hlevnjak, b. & gold, h. (1996): replenishment of the groundwater from precipitation in osijek area. xviiith conference of the danube countries on hydrological forecasting and hydrological bases of water management.− proceedings, a45− a50, graz. manuscript received july 19, 2010 revised manuscript accepted december 28, 2010 available online february 22, 2011 palaeoenvironmental and archaeological implications of a sediment core from polje čepić, istria, croatia andrea l. balbo1, maja andrič2, josip rubinić3, andrea moscariello4 and preston t. miracle1 1. palaeoenvironment and archaeology: overview on the project aims this paper further develops the study of the prehistoric population of istria launched a decade ago (miracle & forenbaher, 2006). the initial study focused on the exploration and excavation of archaeological cave sites. in the last two years, we have undertaken a new geoarchaeological study of open environments situated around polje čepić, not far from some of the richest caves excavated in istria (fig. 1). our overall aim is to provide palaeoenvironmental and archaeological information for land and water management in karstic areas of the mediterranean realm. the slavic word polje literally translates into field or plane. in karstic geomorphology polje indicates a tectono-karstic depression typically found in dalmatia and often occupied by a karstic lake (jennings, 1971, 1985; o’sullivan, 2004). the holocene environments and landscapes of istria are not well known, mainly due to the lack of suitable palaeoecological sites. in addition, the neighbouring locations studied so far are close to the adriatic coast and reflect changes over wide areas for the mid and late holocene (beug, 1967, 1977; culiberg, 1995, 1997). at the few inland sites that have been investigated, for example zajezeri– vodenjak (culiberg, 1995) and prapoče (andrič, 2001, 2006), pollen and organic remains are only seldom preserved in holocene sequences. polje čepić constitutes an optimal site for the development of a comprehensive palaeoenvironmental/palaeoclimatic study in the east-adriatic region because its position and size are likely to reflect both local and regional changes, and organic and pollen preservation is excellent. our research aims to: (1) determine for how long a lake had existed in polje čepić before 1932; (2) determine whether people had been living around the polje in prehistoric times, and how they could have contributed to the progressive siltation of the basin; (3) explore the relationships between the population of open-air landscapes and the environmental changes that took place during the holocene. in 2004 we undertook a systematic survey to identify open-air archaeological sites and reconstruct past environmental conditions around geologia croatica 59/2 109–124 7 figs. 1 tab. zagreb 2006 key words: holocene, lake sediments, geoarchaeology, palynology, mediterranean karst. 1 department of archaeology, university of cambridge, cambridge cb2 3dz, united kingdom; e-mail: alb55@cam.ac.uk, ptm21@cam.ac.uk 2 institute of archaeology, zrc sazu, novi trg 2, slo-1000 ljubljana, slovenia; e-mail: maja.andric@zrc-sazu.si 3 faculty of civil engineering, university of rijeka, viktora cara emina 5, hr-51000 rijeka, croatia; e-mail: jrubinic@gradri.hr 4 department of geography, university of cambridge, downing place, cambridge cb2 3en, united kingdom; e-mail: a.moscariello@shell.com abstract palaeoenvironmental and archaeological records provide an invaluable framework for land and water management in karstic areas of the mediterranean realm. we present the results from analyses carried out on three segments of a sediment core extracted in 2004 from a portion of polje čepić (istria, croatia), a tectono-karstic depression covered in water until artificial drainage took place in 1932. we used bulk sediment analyses, pollen analysis and radiocarbon dating to assess the possible contribution of people to the progressive siltation of the lake, and compared our results with recent archaeological discoveries made on the polje margins. the dating of the sequence points to the presence of a predominantly wet landscape at the coring location since at least 7000 years cal bp. the coincidence of cereal type pollen grains with several open-air archaeological sites indicates that smallscale agricultural practices possibly developed around the polje in neolithic times, ca 6500 years cal bp. concentrations of charcoal in the sediment core at this time suggest the use of fire clearance as part of the agricultural practice. during the bronze and iron ages, the possible intensification of forest clearance and agricultural practices is indicated by: (1) an increase in the number and type of archaeological sites found around the polje; (2) a more open plant landscape in the upper part of the analysed sequence; and (3) a three-fold increase in the sedimentation rate, possibly starting as early as 4000 years cal bp. wetter climate conditions and higher erosion of the surrounding slopes probably led to the progressive siltation of the lake. finally, in 1932 the lake was artificially drained and istria lost its largest natural basin of fresh water. 110 geologia croatica 59/2 polje čepić (balbo et al., 2004). we discovered fourteen previously unknown prehistoric areas, and testexcavated four of them (balbo, 2006; balbo et al., in press). in addition, we extracted an exploratory core from the polje, the analysis of which is presented in this paper. 1.1 the study area polje čepić is situated in the eastern–central part of the istrian peninsula, at the northernmost tip of the adriatic sea (fig. 1). most historical maps of istria, dating back to the 16th century show that polje čepić was occupied by a shallow lake, until its complete drainage in 1932 (parenzan, 1928; lago & rossit, 1981; balbo, 2005). the boljunšćica river constituted its main natural inlet. most of the lake water used to outflow through underground sinkholes, mainly situated on the southern margin of the polje. when high water levels occurred, the lake drained into the raša river (fig. 1). the polje formed following miocene tectonic movements and is situated on an elongated depression developed on the western side of a structurally complex anticline (mihljević, 1998; roglić, 1950). the polje is surrounded and underlain by terrigenous eocene bedrock, flysch (šikić & polšak, 1973). these flysch deposits form a low relief landscape on the eastern and northern parts of the polje, characterised by a network fig. 1 location of polje čepić within istria and croatia (a). a three-dimensional model of the study area shows (b): the approximate extent of the lake occupying the polje before 1932 (1), the location of the core (2), the course of the boljunčica river (3), the main artificial channel (4) connecting the boljunčica river to the rakita channel (5) and the raša river (6), the artificial tunnel through which the lake was drained (7), plomin bay (8), and mount učka (9). 111balbo et al.: palaeoenvironmental and archaeological implications of a sediment core... of shallow river incisions. to the east the polje is contained by the western flank of a n–s trending anticline, characterised by thrust structure of cretaceous carbonates (herak, 1991). this flank forms the steep slopes of the učka mountains incised with a series of deep gullies. most soils within the polje catchments developed both on terrigenous rocks of the flysch zone and on the carbonates of the učka/ćićarija and central istria zones (durn, 2003; škorić et al., 1987). 2. coring technique the exploratory core presented here was extracted from polje čepić in august 2004, at the geographical position n 45°.18759, e 14°.15909, at an altitude of 27 m asl. the drilling equipment used was a rotation/percussion wire line drill, normally used for commercial geological research. the core was recovered in 12 drives, reaching a maximum depth of 17.43 m. due to the nature of the coring equipment, portions of the core were deformed during its extrusion (fig. 3a). the top portion of each drive had deformations caused by the rotation of the coring piston and the water-pressure extrusion technique (leroy & colman, 2001). all segments of the core were extruded into half-cut pipes and sealed with cling film and aluminium foil to preserve moisture and avoid penetration of light. each segment was labelled and stored in a cold room at the archaeological museum of istria (pula), before being transported to cambridge for sampling and analysis. the disturbed segments of the core were not analysed, and archive core segments were kept for future reference. although the three undisturbed core segments from the lowermost three drives are discontinuous, they provide useful information about the history of the basin. analyses of the core were carried out at the department of geography, quaternary research (qr), university of cambridge, at the institute of archaeology, research centre of the slovenian academy of sciences and arts, ljubljana, and at the institutes of botany and geology, university of bergen. accelerator mass spectrometry (ams) radiocarbon dating was carried out at the poznan radiocarbon laboratories (prl). 3. methods 3.1. radiocarbon dating seven samples for ams radiocarbon dating were prepared following the protocols established at the norwegian past environments & climate centre (norpec) and at qr. based on sediment analyses and on the obtained dating we decided to restrict our analyses to the three undisturbed segments presented in this paper. the equipment was washed before each operation and all samples were taken in 1 cm slices. the materials to be dated were separated from the core with steel spatulas, sieved through a 100 µm mesh, and picked up with steel forceps under the stereomicroscope. non-carbonised terrestrial plant remains and carbonised remains were sampled for dating. aquatic plant remains were excluded in order to avoid distortion due to the reservoir effect (björck & wohlfarth, 2001; geyh et al., 1998). sediment residue was removed from the plant materials under the stereomicroscope using soft steel forceps and a synthetic pencil. plant remains were identified as precisely as possible before being dried in the oven at 60°c, weighed, and sent to prl. 3.2. sediment analysis non-destructive methods were initially applied to determine the best-preserved parts of the core and the location of irregularities, clasts, and laminations. the lowermost 10 m of the core were x-rayed using a smr ltd nova hf 30 set at 68 kv and 20 ma, to obtain good luminosity and contrast. rapid film with no grid was used, maintaining a constant focus of 100 cm. wholecore magnetic susceptibility (ms) measurements were taken using a bartington magnetic susceptibility meter connected to a pc and a loop sensor (nowaczyk, 2001). following these first analyses the core segments were split and described. the first description of the split core segments involved the semi-quantitative colour determination of the sediments using a munsell soil colour chart. a fully quantitative digital colour (dc) determination was carried out with a stellarnet spectrometer. sediment samples were taken at regular intervals of 2 cm, with a 1 cm3 brass volumetric sampler. samples for particle size determination (psd) were put in 50 ml test tubes, a 4.5% sodium pyrophosphate (na4p2o7) solution was added and test tubes were left in a water bath at 90°c (194°f) for 5 hours to disperse clay particles. each sample was then centrifuged and run through a malvern mastersizer 2000, to measure particles sizes between 0.02 and 2000 μm (last, 2001). further subsamples were run through the mastersizer two more times: first after eliminating the om in a 30% hydrogen peroxide solution (h2o2), and second after treatment in a 7% hydrochloric acid solution (hcl) to eliminate carbonates. particle size categories are as defined in last (2001). the relative moisture, om, charcoal, and carbonate (caco3) contents in the sediments were measured through loss-on-ignition (loi), using a 1000oc muffle furnace. all samples were weighed, kept at room temperature (20°c) for 3 hours, and reweighed to determine percentage moisture content. samples underwent three more overnight (12 hours) heating cycles at 400°c (752°f), 480°c (896°f) and 950°c (1742°f). at the end of each heating cycle, samples were cooled at 105°c and weighed. the mass loss between 105°c and 400°c was used as a proxy for om content, while the mass loss between 105°c and 480°c was assumed to represent the content in charcoal. finally, the mass loss between 105°c and 950°c was taken as an indicator of the carbonate content (nelson & sommers, 1996). 112 geologia croatica 59/2 fig. 2 comparison of age–depth models from the adriatic sea and circum-adriatic lakes. all age–depth models, excluding that for polje čepić, have been drawn based on published primary data. all dates were calibrated using calib rev 5.0.1®. ages on the horizontal axis are in years cal bp, depths below the sediment surface are in metres. a polynomial trend-line of order 2 has been fitted to each age–depth model. polje čepić (a). malo jezero (b) croatian lake on the island of mljet, dalmatia; two age–depth models are proposed: black line (jahns, 2002), and grey line (wunsam et al., 1999). lake monticchio (c) italian volcanic lake (allen et al., 1999; wulf et al., 2004). lake ioannina (d) greek polje lake in epirus (lawson et al., 2004). rf93–30 (e) adriatic core (oldfield et al., 2003). ad91–17 (f) adriatic core (sangiorgi et al., 2003). a b c d e f 113balbo et al.: palaeoenvironmental and archaeological implications of a sediment core... photographs were taken with a scanning electron microscope (sem) from core segment s2, to determine the origins and nature of the carbonates present in the sediments. samples were coated with 30% gold and 70% palladium using a polaron equipment limited self coating unit e5100, before observation on a philips xl30feg sem. 3.3. pollen analysis samples for pollen analysis were collected using a 1 cm3 brass volumetric sampler. standard laboratory procedures were used for sample preparation (7% hcl, 10% naoh, 40% hf, acetolysis, staining with safranine, silicone oil, method b in berglund & ralska-jasiewiczowa, 1986; bennet & willis, 2002). two tablets with a known number of clubmoss spores (lycopodium) were added to each sample during the first stages of laboratory preparation, in order to determine pollen concentration (stockmarr, 1971). a nikon eclipse e400 light microscope at 400x magnification was used. pollen types were identified by comparison against pollen keys (moore et al., 1991; reille, 1992, 1995) and the pollen reference collection held at the institute of archaeology in ljubljana. microscopic charcoal from each sample was also counted, considering two size classes: <40 µm and >40 µm. 4. results from the study of polje čepić sediments 4.1. preliminary age–depth model seven radiocarbon dates were obtained from the sediment core extracted from polje čepić, three of which gave reverse ages. each of the three lowermost core drives considered in this thesis measured ca 2-m in length. two of these core drives had a diagnostic vshaped ‘wavy’ feature at ca 50 cm from their base (fig. 3a). such features can sometimes result from sudden alluviation, with consequent mixing of sediments, ultimately leading to reverse ages. in alternative, mixed sediments and reverse ages can result from distortion of the core during extrusion. in this case study, the 2 vshaped features occur at the same point (50 cm from the base) in two different core drives, in axis with the vertical coring direction. based on the recurrence of these factors, the three reverse dates were attributed to deformation of the core drives during extrusion. as a result, the three reverse dates (1532 cm, 1665 cm and 1678 cm depth) were dismissed. the portions of each core drive situated above these v-shaped features were therefore excluded from further analysis. the final age–depth model is based on the remaining 4 dates. dates were calibrated using calib rev 5.0.1® based on the intcal 04 calibration dataset (table 1) (stuiver & reimer, 1993; stuiver et al., 2005). median ages were used to create a preliminary age–depth model (fig. 2a). 4.1.1. comparison with age–depth models from neighbouring regions attempts to compare heterogeneous records (e.g. from ice, sea, and lakes), covering different spatial and temporal scales, have allowed correlating climatic and environmental events at local, regional, and global levels (bartlein, 2007). the age–depth model obtained for polje čepić has been compared with five continental and marine sediment sequences recovered around the adriatic (fig. 2): (a) three age–depth models were obtained from continental sequences extracted from lake ioannina (also pamvotis, greece – lawson et al., 2004), malo jezero (island of mljet, croatia – jahns & van den bogaard, 1998; wunsam et al., 1999; jahns, 2002), and lake monticchio (central italy – allen et al., 1999; wulf et al., 2004); (b) two age–depth models were based on marine sediment sequences from adriatic cores rf93–30, and ad91–17 (oldfield et al., 2003; sangiorgi et al., 2003). the discontinuity of the record recovered from polje čepić did not allow a multi-proxy correlation. the preliminary comparison proposed here is solely based on radiocarbon dating and has been restricted to the past 10000 years. laboratory midpoint material weight conventional age years cal age years cal median years code (gr) age 14c bp bp (1σ) bp (2σ) cal bp poz-10877 1351 (s3) bark, stem, 1 scirpus seed 0.0051 3620±35 3887–3978 3839–4074 3931 poz-10878 1532 bark 0.0281 3490±35 dismissed poz-10880 1568 (s2) 9 scirpus seeds 0.0104 5370±35 6119–6273 6007–6279 6185 poz-10881 1582 (s2) bark 0.0159 5720±40 6446–6560 6412–6633 6514 poz-10882 1665 bark, stem, 1 scirpus seed, charcoal 0.0122 5290±40 dismissed poz-10883 1678 bark, charcoal 0.0105 4740±35 dismissed poz-10884 1686 (s1) charcoal (juniperus) 0.0152 6040±40 6802–6945 6759–6997 6889 poz-12231 1678 bark, charcoal 0.0105 4765±35 replica poz-12232 1686 charcoal (juniperus) 0.0152 6080±35 replica table 1 results from the ams dating. following the occurrence of reverse dating, prl repeated two samples at 1678 cm and 1686 cm depth obtaining similar results to those from the original analyses. 114 geologia croatica 59/2 fig. 3 core log and sediment description. (a) example of a v-shaped core deformation. in contrast with polje čepić, malo jezero (a coastal dalmatian lagoon) features a decreasing sedimentation trend throughout the holocene. a linear sedimentation trend is noticed at monticchio lake, a volcanic lake, pointing to constant sediment accumulation throughout the holocene. among the continental sequences, lake ioannina (a shallow polje lake) shows a sedimentation trend similar to polje čepić (brousoulis et _ .. ,,.. 'm •• •• •• •• ••• ... .... •• -. •• •• •• ~. •• •• •• .~ .~ ... ,,,. .~ .~ .m . ~ ... --­~ 130151380 _ "!i' oy." '' '_i , !y"",," (0l' ___ 1 .... s,,"'r-.. _iip) ,= ,-, ... 5'1'2 si' (1,1) = '_'li' "" 5'1'2.51'11" ) , ,3u,.,:m_ .,., .... , i") = ,""","", an 5y2s1h") ~i~"a. ,cs2 ~ ,""'.,5el",,, .. "''''''1'') =. ,5&1_,57, "'" 5yurq .. ) ~"s ''''('''''''''''''''''''' = ,.,,., ... "" ... "',"', (iii ~ .. s ,:w,>7"" .. ...,..tjp ~" '~h"_ 1vl.5i1 'y2,~ (100) ..... s, ... ~_"" " 111),1111·,1.03 "" 1y7i1,"'1 2''fmi(_1 _ <ioy_" (ioics1 _ " ., ... , .. _ ..... "' _"' ____ ' 3oe .... '.71"'"_ "'" --....... om __ , ... ..,. '311 "'" __ """ __ • ''''''_1~_1170 __ 04 ....... "" <loy ...... ,ocs) __ '9*il) ...... thoorly _ .... l __ .. ,1i,,," ___ ., ...... __ d ... -ocs· ...... __ ""'_ ....... ..., ..... __ _ in ......... ( ..... _ .. '!1m __ i ""sell "",_01 __ "", ocs. ...... __ (li.i.<o:ft dol' __ '" ..­ -"',-,."'''''cioyoy .......... (css) __ _ .... " ..... " _ 01 om ..,. """"""'__ __ '''2 .... '5011"" __ , ... ___ "72 .... ,..., ""' __ ... _ co...om .. ,_ ""_ lc$· __ ............ _dom .... _ 00\'-._"' ..... _ ..cs; -.. .. ""'" ____ e 1ofoi'''''''' --.. -~ .... -­~ bonodd. , .......... ..., .. '1185 __ c<w",_ •• ,"""",,_ 0.0.,1:» i) (»pi -., __ ....... """ ..., _ "' ___ m ..... m1<.1'1 __ ""'''''' ~ .. _.,. ... _", __ w.,_. i .. ,· · ".. ... ' .. f ........... _ 0'_1 __ ....... ....,"""' .. , .... '" ------",.""--_ .. " __ ""*" a... ___ ,,,,, .... _ .... __ .. "0""",so. ' " "'<1' : .. ......,.. __ • _ .... _~ .-• ""-""',.., ....... :31 «>_ ........... s ""-_ ... ~ "--• ""'_<10>""''' <j p-115balbo et al.: palaeoenvironmental and archaeological implications of a sediment core... al., 1999). however, accelerated sedimentation at lake ioannina seems to have begun earlier than at polje čepić. marine sediment core rf93–30, extracted from a shallow portion of the central adriatic, presents a sedimentation trend matching the results from polje čepić (oldfield et al., 2003). in contrast, core ad91–17, extracted from a deep portion of the southern adriatic, shows an inverted trend compared to polje čepić. similarities observed between rf93–30, polje čepić and lake ioannina may partly result from their shallowness. the rapid increase in sedimentation observed in core rf93–30 after ca 4 ka cal bp has been interpreted as anthropogenic (oldfield et al., 2003). this hypothesis will be discussed in relation to the observations made at polje čepić. 4.2. core description and physical analyses 4.2.1. core description most of the observed sequence is composed of laminated or sub-laminated sediments of limnic origin. the only peat (lignite) layer was found between 1391 and 1398 cm. the three core segments described here are from the bottom part of the three lowermost drives and are (from the bottom upwards) s1, s2, and s3. each of these segments has been subdivided into several units, based on sediment observations (fig. 3). these units are characterised by well-preserved horizontal bedding lamination planes. core segment s1 represents the bottom of the sequence, between 1685 and 1743 cm depth. this segment was subdivided into two units. the lower detritus unit (d) represents the transition from a heterogeneous assemblage of clasts and sandy-clay (d bottom) to finer laminated sediments (d top). organic matter (om) is almost absent in this unit. the upper unit is composed of massive to finely laminated clay and silt (mcs1), with millimetric fragments of charcoal. core segment s2 was extracted between 1550 and 1598 cm depth, and subdivided into five units. laminated clayey silt (lcs1 and 2) and clayey silt and sand units (css) characterise the lower part of this core section, while organic-rich clay and silt units (ocs1 and 2) are found towards the top. core segment s3 was extracted between 1345 and 1398 cm depth, and divided into four units. the lower unit represents the only lignite (l) found within the analysed core segments. in this core segment the om content seems to be gradually decreasing towards the top. above l, sediments gradually shift from organic rich clay and silt (ocs3) to laminated clayey silt (lcs2) and massive clay-rich silt (mcs2). this core segment is rich in partially decomposed speckles of horizontallylayered om and shells. 4.2.2. particle size determination core segment s1 is the best sorted, with the lowest inclusive standard deviation throughout the psd analysis (fig. 4). the bottom unit d of core segment s1 could not be processed with the mastersizer because of its detritic nature. unit d is mainly composed of cobbles and angular clasts embedded in a clayey-silt matrix. the mcs1 unit shows little variations in the size distribution of its components through the three phases of measurement. its sedimentary regime appears to be very stable throughout its extension, with a net dominance of silts (>80%), followed by clay (8–10%), and sand (5–10%). the distribution of particles through core sediment s2 shows a generalised increase of clay size particles (5 to 15%) compared to silt and sand particle sizes after treatment with h2o2. the grain size distribution pattern remains similar after treatment with hcl. sand size particle peaks occur at 1578 cm (30%), and 1568 cm and 1558 cm depth (40%). in core section s3 the particle distribution shows little change after treatment with h2o2 and hcl. there is a generalised gain of about 20% on the clay particle size compared to sand size after treatment with h2o2, while changes are minimal after treatment with hcl. two contrasting trends can be observed. a first one towards decreasing particle sizes up to 1366 cm depth, and a second one towards sand sized particles towards the top of this core segment. core segment s3 is the most poorly sorted before treatment with h2o2 and hcl, while s2 is the most poorly sorted after om and carbonates are eliminated. 4.2.3. magnetic susceptibility ms values remain constant throughout core segment s1, where they reach the highest readings. ms values decrease gradually through core segment s2, reaching minimal values just over 1.0 si units. as for core segment s3, ms values increase steadily, stabilising around 4.5 si units above 1365 cm depth. 4.2.4. loss-on-ignition in core segment s1 unit mcs1 shows a very stable pattern throughout loi analysis, with a net prevalence of silicate residue (90%) and low om (5–7%), carbon (less than 2%), and caco3 (5%) content. inclusive mean is stable around 6.5 φ, pointing to medium and coarse silts as the predominant particle sizes. in core segment s2 inclusive mean values are generally lower than those registered for core segment s1. a general trend is observed, with increasing particle sizes towards the top, where particle sizes from the silt–sand boundary are the most represented. a peak in carbonate content is recorded at 1580 cm depth, followed by a rapid increase in the amount of carbon (4 to 6%) and om (10 to 35%). the highest peak in carbon content is recorded at 1568 cm depth. clay-size detritus is the main component of the carbonates from this core segment. some sponge needles and diatom fragments are present (fig. 5), as well as infrequent shells and ostracods. core segment s3 is generally dominated by silicate residue, stable around 116 geologia croatica 59/2 80%. this core segment is characterised by a progressive decrease in om, in coincidence with a progressive increase in carbonates. 4.3. pollen record polje čepić is located in a relatively large tectonic depression. historically, the polje has been occupied by a lake extending over an area up to 6 km2 (parenzan, 1928). therefore, the pollen record from this basin is likely to represent past plant composition at local, extra-local and regional scales. while the effects of the early introduction of local small-scale forest clearance and agriculture are detectable through pollen analysis in small basins (with <30 m diameter) they are overwhelmed by the regional pollen record deposited fig. 4 results from ms, psd, and loi. ms is measured in si units; loi results are presented in %; inclusive mean is measured in φ; clay, silt and sand proportions are presented in % and in a cumulative way following the results from psd analyses after treatment with na4p2o7 (dark grey), h2o2 (grey) and hcl (light grey). 117balbo et al.: palaeoenvironmental and archaeological implications of a sediment core... in larger basins (jacobson & bradshaw, 1981), such as polje čepić. nevertheless, the accurate observation of seemingly minimal changes in the pollen record recovered from larger basins can be used to detect the possible effects of agro-pastoral practices on changes in plant and forest composition (fig. 6). preliminary examination of the three core segments showed that pollen was only preserved in the upper two segments. pollen is not preserved throughout the lowest core segment s1. no pollen is preserved in the lowest levels of core segment s3, at 1384 cm and 1390 cm depth. the best pollen preservation is recorded for the middle core segment s2, with pollen concentrations reaching 7000–14000 grains/cm3. a major peak in the input of coarse microcharcoal (>40µm) is registered at 1568 cm depth. only one sample was analysed from core segment s3 at 1360 cm depth, where pollen concentration is lower than that observed for core segment s2, with less than 2000 grains/cm3. throughout most of the time span covered by core segments s2 and s3 the environment around the coring location was wet enough to allow pollen preservation. the pollen record suggests that beech (fagus) was an important tree taxon before 6500 years cal bp, which is consistent with charcoal and phytolith analyses from the archaeological site of pupićina cave where beech abounds in the mid-holocene layers (fletcher, 2002; fletcher & madella, 2006). this is probably because the ćićarija and učka mountains provide an orographic barrier to the north and east (up to 1394 m asl) of the study area, retaining the clouds coming from the adriatic sea, and increasing precipitation. pollen diagrams from škocjanski zatok near koper suggest that the mid-holocene vegetation of northern istria was dominated by broadleaved taxa, with a high percentage of beech (culiberg, 1995, 1997). conversely, pollen analyses from vrana lake, on the island of cres, 50 km eastwards, suggest that oak (quercus) was there the most important tree taxon throughout the holocene, although an increase of beech and fir (abies) occurred after ca 9600 cal bp (schmidt et al., 2000). 5. interpretation of core evidence 5.1. s1 (1743–1685 cm, previous to ca 6830 years cal bp) the lowest part of core section s1 (fig. 3, unit d) has not yet been dated, but is significantly different from the others studied here. unit d is the result of a massive colluvial discharge and therefore a sedimentation gap could exist between units d and mcs1. if so, unit d could have been deposited during a period of rapidly changing climate at the lateglacial–early holocene transition. alternatively, the predominant siliceous component, with its steady trend towards more laminated and finer particle sizes and the almost complete absence of om and pollen could be due to slope failure associated with a major tectonic event, such as the one recorded on mljet island by wunsam et al. (1999). high ms values in this part of the core point to a significant, and perhaps rapid, input of mineral sediments. the laminated clays and silts of unit mcs1 and its stable and wellsorted particle size pattern seem to reflect the establishment of a lake fed by intermittent streams. fig. 5 six photographs of the sediments taken with sem. the top three photos were taken from 1568 cm depth, the bottom ones from 1580 cm depth. photos 1, 5 and 6, show clay particles and structures (5) potentially indicating the formation of shallow hydromorphic soils during low water stands; photos 2 and 3 a sponge spicule, and photo 4 part of a diatom. 1 2 3 4 5 6 118 geologia croatica 59/2 fig. 6 pollen diagrams (selected taxa). radiocarbon dates are reported in years cal bp. the quantity of individual pollen taxa is presented in percentages (calculated from the sum of all terrestrial-taxa and spore pollen). for summary diagram the percentage of trees and shrubs (ap) and herbs, spores and aquatics (nap) was calculated from the sum of all taxa. the sum of terrestrial taxa and spores is in absolute numbers. pollen and charcoal concentration are given in number per cm3. all pollen data is presented (a) as well as a detail of the results obtained for s2 alone (b). in (a) data are presented as simple bars in reason of the large gap between s2 and s3. the only exception was made for the ap/nap ratio, where bars are linked by dashed lines to show the changing ap/nap trend between samples 1560 and 1360 cm depth. abbreviations to be read as follows: quercus i. (ilex type), carpinus o. (orientalis type), fraxinus e. (excelsior), fraxinus o. (ornus type), cereal (type), plantago l. (lanceolata type), compositae lig. (liguliflorae type), typha l. (latifolia type) and sum terr. (terrestrial) taxa and spores. ind – indeterminable. italic is used for taxa if pollen is determined to genus level, while normal letters are used for taxa if pollen is determined to family level. f f f' f f f -----' f f f j f .1 it f f f f f f f 119balbo et al.: palaeoenvironmental and archaeological implications of a sediment core... 5.2. s2 (1598–1550 cm, ca 6600–6000 years cal bp) core segment s2 probably represents a progressive lowering of the water level in the polje. the lower portion of this core segment, represented by units lcs1 and css, contains microlaminations and occasional fine sand laminae. the intermittent input of coarser materials represented by the sand peaks at 1578, 1568, 1554 and 1558 cm depth could be due to sudden wet and erosive episodes, but generally this core segment seems to suggest the onset of progressively drier conditions. the clay particles and structures characterising the sediments from unit css (fig. 5) potentially indicate the formation of shallow hydromorphic soils during low water stands. the peak in carbonates at 1580 cm depth could be a consequence of a higher concentration of microorganisms and aquatic plants fixing caco3 in the lake, due to lower water levels (mackereth, 1966; kelts & talbot, 1990). this carbonate peak is followed by a significant increase in om and charcoal within the lake sediments. the content in om increases toward the top of core segment s2, in units ocs1, lcs2 and ocs2, also indicating the establishment of low water levels. furthermore, the relatively low ms readings from this part of the core point to lower terrigenous input with siliceous sediments only episodically reaching the basin. tree pollen is dominant throughout core segment s2, constituting ca 90% of the total pollen sum: the record suggests that ca 6600 years cal bp (1590 cm depth) the landscape around polje čepić was covered by a thick forest of shade-tolerant beech (40%), and oak (26%), fir (11.8%), and hazel (corylus 5.8%). herb-type pollen remains stable around 2% throughout core segment s2, but after 6500 years cal bp forest composition changed appreciably towards a more open type of forest, characterised by the decline of beech (27.3%) at 1568 cm depth (ca 6150 years cal bp), and an increase of oak (29.8%) and hazel (11.7%). 5.3. s3 (1398–1345 cm, ca 4420–3870 years cal bp) the absence of pollen grains at 1384 and 1390 cm depth, as well as the presence of lignite (unit l) and the abundance of only partially humified om within unit ocs3 suggest a low water level stand at the coring site. the 3 units l, ocs3, and lcs2 probably represent a transitional phase from dry conditions with peat formation, to a wetter environment with deepening water, also indicated by laminated and massive clayey and clay-rich silt (units lcs2 and mcs2) towards the top of core segment s3. the top unit mcs2 contains abundant amounts of shells, indicative of established limnic conditions at the top of this core segment. at ca 3900 years cal bp (1360 cm depth) polje čepić was surrounded by relatively open, mixed woodland. when compared to core segment s2, s3 denotes a relative decline of oak and other tree pollen taxa, with trees and shrubs representing only 70% of the total pollen sum. this decline and the simultaneous increase of non-arboreal taxa, with herbs reaching 7.3% of the total pollen sum, indicate a more open landscape. 6. discussion this study covers three time periods between ca 7000 years cal bp and 3800 years cal bp providing new evidence on palaeoenvironmental and vegetation change in polje čepić and its surroundings. using a combination of archaeological and palaeolimnological evidence, we suggest the following account of polje čepić and the people living on its margins during those periods (fig. 7). 6.1. archaeological evidence a recent archaeological survey carried out on the margins of polje čepić, provides strong evidence for the presence of people during the last 25,000 years (balbo, 2006; balbo et al., 2006). the periods covered by the core segments are well represented in the archaeological record. human occupation for the period covered by s2 is characterised by five open-air lithic scatters on the margins of the polje. organic material was not preserved at these locations, owing to exposure to weathering and modern agricultural practices. in the absence of absolute radiocarbon datable materials, the age of these archaeological assemblages was inferred by association with radiocarbon-dated cave sites studied in the wider region. in particular, the lithic assemblages from the open-air sites discovered at frankoli and ivšišće present artefacts that could be associated with those found at pupićina cave, located less than five kilometres northwards (miracle & forenbaher, 2005; balbo et al., 2006). within the lithic assemblages discovered at frankoli and ivšišće three obsidian fragments of probable liparian origin were found (balbo, 2006; balbo et al., in press). fragments of the same raw material were found in the late neolithic horizon g at pupićina cave, dated between 6219 and 6477 years cal bp at 1σ (miracle & forenbaher, 2005). the most recent periods, covered by core segment s3, are associated with the presence of large communities living around polje čepić. such communities have been well documented (petrić, 1979). kožljak and kršan are two major examples of late medieval settlements erected upon protohistoric hillforts (castellieri) dating back to the 2nd millennium bc. in a recent archaeological survey a probable bronze age settlement was (re)discovered on the northern tip of the polje (balbo et al., 2006), on a hilltop locally known as gradina (marchesetti, 1903). six previously unknown lithic scatters and buried agricultural soil horizons possibly of the same age, were also discovered on the margins of the polje (balbo et al., 2006). 120 geologia croatica 59/2 6.2. palaeolimnological evidence the neotectonic depression represented by polje čepić has been occupied by a wet, mainly lacustrine landscape, for most of the time span covered by the present study. our analyses suggest that the water body and surrounding vegetation underwent significant changes during these periods of time. the archaeological, sedimentological, and palynological records, notably the increase in non-arboreal pollen (nap) in s3, support the hypothesis that forest clearance by people living on the margins of the polje contributed to such changfig. 7 diagram summarising the main results issued from the present study. , if ~ i::.. ,p ~¢o::-'? • , .0 , ~ .~.p i ' .§>o~ "l'~ ~& 18> p:'b.[j ~'" ,lect,,';i' i 6' • b' &~'/ <qr§q,:'q, is' 0'" " v -<:-~ oj'" <p " ~ i; "'5 53 mcs2 · 0 i 3883 • 0 • 3932.5 . >350 vrana $ potsherds " , 1355 0 0 ~ i , "" i 1365 • ., , ! 0 1370 i i • h 1375 , • • , ' -1380 0 , ': ~ lcs2 , , j] 1385 0 " ocs3 • • [~ "90 • l 1395 '. '''0 ocs2 • 0 1555 0 • .• " "'" ~ 0 ---lcs2 ocs1 0 • , cvitiv~ '565 • '''' i • sm ... seale fo<eit 1570 ~ dearance by f~e css " 1575 ''''' • • pupitina '580 dry &pei1 6503 • obsidian '585 • 0 ; • 0590 les! i , 0 1595 " • • 51 6873.5 _ "" mes 1 · 0 " 90 0 " 1695 0 0 , """ 1705 1710 • 171 5 d , h2o 1725 • f 1'30 0 • • " 0 . , 1735 , ii 0 ""0 " h , • 121balbo et al.: palaeoenvironmental and archaeological implications of a sediment core... es since ca 6500 years cal bp, and particularly so after 4000 years cal bp. a high carbonate peak around 6500 years cal bp, may indicate a sudden lowering of the water level in the lake occupying the polje, with a consequent acceleration in the fixation and deposition of carbonates and possible soil formation. after ca 6500 years cal bp, the amount of carbonates deposited in the lake decreased. this and a progressive lowering in ms values suggest the establishment of low water conditions. the early phases of this period coincided with a sudden increase in the input of om and charcoal. the relative coarseness of the charcoal (>40 µm) points to its input in the basin from relatively short distances within its catchments (whitlock & larsen, 2001). after ca 6150 years cal bp (1568 cm) and within about a 100 years, a significant forest composition change seems to have taken place around polje čepić. beech declined in favour of oak, indicating the establishment of a more open forest, dominated by photophilic (light-demanding) oak. at the same time cereal-type pollen grains made their first appearance in the region, just after 6150 years cal bp at 1562 cm depth. five of the sites recently found on the margins of the polje have been associated through typochronological comparison with the late neolithic horizon g dug in the nearby pupićina cave, dated between 6219 and 6477 years cal bp. the simultaneous appearance of cereal-type pollen grains and the unusual concentration of microcharcoal (also revealed by loi analysis) indicate a possible link between the decreased tree cover and the introduction of small-scale forest clearance and burning by neolithic settlers just before 6000 years ago. our preliminary age–depth model, with its increased sedimentation rate after 4000 cal bp, is consistent with the model proposed by oldfield et al. (2003). the lowermost 3 m of sediments accumulated at the core location over 3000 years, between 7000 and 4000 years ago, at an average rate of 1 mm/yr. in contrast, the average sedimentation rate in the top 14 m of the core tripled in the last 4000 years to 3.5 mm/yr. sedimentological analyses of the sediments for the period represented by s3 point to higher water level in the shallow lake occupying the polje. at the same time, a steady increase in magnetic susceptibility throughout s3 indicates an increase in the input of sediments within the polje. such peaks in ms are often linked to periods of deforestation, and consequent erosion of mineral soils (sandgren & snowball, 2001). in addition, the comparison between the pollen record from core segment s2 and the sample from core segment s3 shows a trend toward an ever more open forest environment. in core segment s2 beech decreases (40 to 26%) to the slight advantage of oak (26 to 30%). in core segment s3 beech and oak decrease even further, respectively reaching 16% and 20%. this trend in vegetation change is also reflected by the decreasing ratio of arboreal versus non-arboreal plants (ap/nap), indicating a shift towards a more open landscape. we propose that the concurrence of wetter conditions, and perhaps the cumulative intensification of forest clearance and agro-pastoral practices, may have resulted in a sharp acceleration of the siltation of the lake occupying polje čepić. in the wider region, the study carried out by oldfield et al. (2003) on core rf93–30, extracted from the adriatic, revealed a sedimentary pattern similar to that obtained for polje čepić. this was interpreted as being the result of increased soil erosion in the po plain due to the intensification of agro-pastoral practices during the bronze age. similarly, the studies carried out at the nearby vrana lake suggest that bronze age communities played an important role in the shaping of the local landscape (schmidt et al., 2000; miko & mesić, 2004; miko et al., 2005). potsherds embedded within colluviums were found on the margins of vrana lake (island of cres), and dated between 3853 and 3926 years cal bp at 1σ range (median of 3883 years cal bp from the original date of 3580±40 years uncal bp in miko et al., 2005). this age range has been correlated with a greater input of sediments in the lake, and seems to coincide with the beginning of oak forest clearance through burning between 3693 and 3895 years cal bp at 1 σ range (median of 3796 years cal bp from the original linear extrapolated date of 3518±80 years uncal bp in schmidt et al., 2000). 7. available proxies for further studies microscopic observations carried out on the core sediments have revealed the presence of several other proxies available for use in palaeoclimatic research. among them were shells, diatoms, midges (chironomidae and related diptera), and ostracods. some of them have been sampled and kept for future observations. reference samples have also been collected from several ponds and rivers within the catchments of polje čepić for the isotopic study of ostracods and water. seeds and other plant macroremains also abound. moreover, the location and characteristics of polje čepić makes it an optimal site for furthering palaeoenvironmental and palaeoclimatic research in connection with other continental and marine sequences available in the mediterranean realm. 8. conclusions in this paper we have demonstrated the potential of polje čepić for enhancing our knowledge of the past in the istrian peninsula and beyond. we propose that lacustrine/wet landscapes have characterised polje čepić and its surroundings before historical times. polje čepić, and other poljes, are ideal sites to study the introduction of agro-pastoral practices and their effects on the transformation of the mediterranean realm during the neolithic and later times. using sedimentological and palynological analyses we have detected hydrologi122 geologia croatica 59/2 cal and palaeoclimatological variations affecting polje čepić and its surroundings. we have shown that people played a significant role in shaping this typical mediterranean karstic wet landscape. palaeoenvironmental and archaeological data suggest that the introduction of agro-pastoral practices contributed to the transformation of the area of study. specifically, we propose that: (1) around 6500 years ago, people may have introduced forest clearance by fire in tandem with small-scale agricultural practices on the margins of the lowered karstic lake, triggering a slight change in forest composition near polje čepić; (2) around 4000 years ago wetter climatic conditions and perhaps the intensification of agro-pastoral practices, coincide with appreciably more open vegetation; (3) these factors probably resulted in increased erosion and sedimentation, leading to the siltation of the lake until its artificial drainage in 1932. acknowledgements the authors wish to thank steve boreham, chris rolf, and phil gibbard (department of geography, university of cambridge), tony burgess (department of anatomy, university of cambridge), gilly thorp (veterinary school, university of cambridge), milan mihovilović and geo5 (rovinj), hillary and john birks, richard telford and hellen schjölberg (institute of botany, university of bergen), michael talbot and stig monsen (institute of geology, university of bergen) nada krstić (beograd), elsa gliozzi (dipartimento di scienze geologiche, universitá degli studi roma 3), maria letizia filippi (museo di storia naturale, trento) and marco madella (icrea barcelona). we are indebted to the marie curie association, the institute of botany, university of bergen, the ahrc, and to the department of archaeology and the mcdonald institute, university of cambridge, for providing most of the funding necessary to the completion of this study. special thanks go to steve roberts for his most constructive comments. we are also grateful to goran durn and three anonymous reviewers for their detailed remarks towards the improvement of this paper. 9. references allen, j.r.m., brandt, u., brauer, a., hubberten, h.w., huntley, b., keller, j., kraml, m., mackensen, a., mingram, j., negendank, j. f.w., nowaczyk, n.r., oberhansli, h., watts, w.a. & wulf, s. (1999): rapid environmental changes in southern europe during the last glacial period.– nature, 400, 740–743. andrič, m. (2001): transition to farming and human impact on the slovenian landscape.– unpubl. phd thesis, universitiy of oxford, 152 p. andrič, m. (2006): prapoče pollen core and holocene vegetation change in northern istria.– in: miracle, p.t. & forenbaher, š. (eds.): prehistoric herders in istria (croatia): the archaeology of pupićina cave. archaeological museum of istria, 31–62, pula. balbo, a.l. (2005): the last days of a mediterranean wet landscape. human impact on and draining of shallow lake arsa, polje čepić, istria, croatia.– 10th unesco universities heritage forum, newcastle, 9 p.; http://www.ncl. ac.uk/unescolandscapes/files/balboandrea%20luca. pdf. balbo, a.l. (2006): people and wetlands in the open karst of istria, croatia.– newsletter of the prehistoric society, 52, 2–3. balbo, a.l., komšo, d. & miracle, p.t. (2004) geoarchaeological survey of polje čepić and part of its hydrological basin (istria peninsula, croatia): report on the first field season.– histria archaeologica, 33, 265–276. balbo, a.l., komšo, d. & miracle, p.t. (2006): prehistory of the open karst, further discoveries from the geoarchaeological survey of polje čepić, croatia.– histria archaeologica, 35, 33–42. balbo, a.l., komšo, d. & miracle, p.t. (in press): open-air mesolithic settlements in a mutable karstic mediterranean biotope. polje čepić (istria, croatia).– in: mccartan, s., woodman, p., schulting, r. & warren, g. (eds.): mesolithic horizons: papers presented at the seventh international conference on the mesolithic in europe, belfast 2005. oxbow books, oxford. bartlein, p.j. (2007): time scales of climate change.– in: elias, s. (ed.): encyclopedia of quaternary science. elsevier, amsterdam, 1873–1883. bennet, k.d. & willis, k.j. (2002): pollen.– in: smol, j.p., birks, h.j. & last, w.m. (eds.): tracking environmental changes using lake sediments. dodrecht, kluwer academic, 5–32. berglund, b.e. & ralska-jasiewiczowa, m. (1986): pollen analysis and pollen diagrams.– in: berglund, b.e. (ed.): handbook of holocene paleoecology and paleohydrology. new york, chichester, john wiley and sons, 455–484. beug, h.-j. (1967): on the forest history of the dalmatian coast.– review of palaeobotany and palynology, 2, 271– 279. beug, h.-j. (1977): vegetationsgeschichtlichte untersuchungen in küstenbereiche von istrien (jugoslawien) (research of vegetation development in coastal areas of istria (yugoslavia).– flora, 166, 357–381. björck, s. & wohlfarth, b. (2001): 14c chronostratigraphic techniques in paleolimnology.– in: last, w.m. & smol, j.p. (eds.): tracking environmental change using lake sediments. dordrecht, kluwer academic publishers, 205–245. brousoulis, f., ioakim, c., kolovos, g. & papanikos, d. (1999): the ioannina basin: geological and palaeoenvironmental evolution in quaternary and historical times.– in: bailey, g.n., adam, e., panagopoulou, e., perlès, c. & zachos, k. (eds.): the palaeolithic archaeology of greece and adjacent areas. british school at athens, athens, 87–96. 123balbo et al.: palaeoenvironmental and archaeological implications of a sediment core... culiberg, m. (1995): dezertifikacija in reforestacija slovenskega krasa (desertification and reforestation of the karst in slovenia).– poročilo o raziskovanju paleolitika, neolitika in eneolitika v sloveniji, 22, 201–217. culiberg, m. (1997): sermin: prazgodovinska in zgodnjerimska naselbina v severozahodni istri (sermin: a prehistoric and early roman settlement in northwestern istria).– in: horvat, j. (ed.): paleovegetacijske razmere v koprskem primorju. opera instituti archaeologici sloveniae zrc sazu, 3, 135–139, ljubljana. durn, g. (2003): terra rossa in the mediterranean region: parent materials, composition and origins.– geologia croatica, 56, 83–100. fletcher, w.j. (2002): late-glacial and holocene vegetation and prehistoric wood-use in the istrian karst, croatia.– in: thiébault, s. (ed.): charcoal analysis. methodological approaches, palaeoecological results and wood uses. 1st ed. paris, bar, 87–94. fletcher, w.j. & madella, m. (2006): characterising the post-mesolithic landscape at pupićina peć: results of charcoal and phytolith analyses.– in: miracle, p.t. & forenbaher, s. (eds.): prehistoric herders in istria (croatia): the archaeology of pupićina cave. archaeological museum of istria, pula, 429–446. geyh, m.a., schotterer, u. & grosjean, m. (1998): temporal changes of the 14c reservoir effect in lakes.– radiocarbon, 40, proceedings of the 16th international radiocarbon conference, 921–931. herak, m. (1991): dinarides – mobilistic view of the genesis and structure.– acta geologica, 21, 35–117. jacobson, g.l.j. & bradshaw, r.h.w. (1981): the selection of sites for palaeovegetational studies.– quaternary research, 16, 80–96. jahns, s. (2002): an improved time scale for the holocene history of vegetation and environment on the south dalmatian island of mljet.– vegetation history and archaeobotany, 11, 315–316. jahns, s. & van den bogaard, c. (1998): new palynological and tephrostratigraphical investigations of two salt lagoons on the island of mljet, south dalmatia, croatia.– vegetation history and archaeobotany, 7, 219–234. jennings, j.n. (1971): karst.– m.i.t. press, cambridge, massachussets and london, england, 252 p. jennings, j.n. (1985): karst geomorphology.– blackwell ltd, oxford, basil, 293 p. kelts, k. & talbot, m.r. (1990): lacustrine carbonates as geochemical archives of environmental change and biotic/abiotic interactions.– in: tilzer, m.m. & serruya, c. (eds.): large lakes. ecological structure and functions. springer-verlag, london, 288–315. lago, l. & rossit, c. (1981): descriptio histrie. la penisola istriana in alcuni momenti significativi della sua tradizione cartografica sino a tutto il secolo xviii. per una corologia storica (descriptio histrie. the istrian peninsula in its cartographic tradition until the 18th century).– trieste, universita popolare di trieste. edizioni lint, 349 p. last, w.m. (2001): textural analysis of lake sediments.– in: last, w.m. & smol, j.p. (eds.): tracking environmental change using lake sediments. kluwer academic publishers, dordrecht, 41–81. lawson, i., frogley, m., bryant, c., preece, r. & tzedakis, p. (2004): the lateglacial and holocene environmental history of the ioannina basin, north-west greece.– quaternary science reviews, 23, 1599–1625. leroy, s.a.g. & colman, s.m. (2001): coring and drilling equipment and procedures for recovery of long lacustrine sequences.– in: last, w.m. & smol, j.p. (eds.): tracking environmental change using lake sediments. kluwer academic publishers, dordrecht, 107–135. mackereth, f.j.h. (1966): chemical investigation of lake sediments and their interpretation.– proceedings of the royal society. series b, biological sciences, 161. a discussion on the development of habitats in the post-glacial, 295–309. marchesetti, c. (1903): i castellieri preistorici di trieste e della regione giulia (prehistoric hillforts of trieste and the giulia region).– il museo civico di storia naturale, trieste, 206 p. mihljević, d. (1998): relief of structural origin and the structural–geomorphological regions of the istria and kvarner.– proc. natural history researches of the rijeka region, 23, 277–302. miko, s. & mesić, s. (2004): geochemical record of holocene land use change and anthopogenic pb deposition in a northern adriatic karst lake (lake vrana, cres island). – 32nd international geological congress, abstracts, florence, 35. miko, s., mesić, s., forenbaher, s. & belak, m. (2005): archeometric analysis of bronze age potsherds from vrana lake (cres island): a study of provenance and dating of slope processes.– abstracts book of 3rd croatian geological congress, opatija, 99–100. miracle, p.t. & forenbaher, s. (2005): neolithic and bronze age herders of pupićina cave, croatia.– journal of field archaeology, 30, 255–281. miracle, p.t. & forenbaher, s. (eds.) (2006): prehistoric herders in istria (croatia): the archaeology of pupićina cave, pula. archaeological museum of istria, pula, 542 p. moore, p.d., webb, j.a. & collinson, m.e. (1991): pollen analysis.– blackwell science, oxford, 216 p. nelson, d.w. & sommers, l.e. (1996): total carbon, organic carbon, and organic matter.– in: bigham, j.m. (ed.): methods of soil analysis: part 3 chemical methods. madison, soil science society of america, 961–1010. nowaczyk, n.r. (2001): logging of magnetic susceptibility.– in: last, w.m. & smol, j.p. (eds.): tracking environmental change using lake sediments. kluwer academic publishers, dordrecht, 155–170. oldfield, f., asioli, a., accorsi, c.a., mercuri, a.m., juggins, s., langone, l., rolph, t., trincardi, f., wolff, g., gibbs, z., vigliotti, l., frignani, m., van der post, k. & branch, n. (2003): a high resolution late holocene palaeoenvironmental record from the central adriatic sea.– quaternary science reviews, 22, 319–342. 124 geologia croatica 59/2 o’sullivan, p.e. (2004): palaeolimnology.– in: o’sullivan, p.e. & reynolds, c.s. (eds.): the lakes handbook: limnology and limnetic ecology. blackwell publishing, malden, oxford, carlton, 609–666. parenzan, p. (1928): il lago d’arsa (the arsa lake).– histria nobilissima, 1, 47–51. petrić, n. (1979): introduzione alla preistoria dell’istria (introduction to the prehistory of istria).– atti, 9, 185– 248. reille, m. (1992): pollen et spores d’europe et d’afrique du nord (european and north african pollen and spores).– laboratoire de botanique historique et palynologie ura cnrs, marseille, 520 p. reille, m. (1995) pollen et spores d’europe et d’afrique du nord (supplement) (european and north african pollen and spores).– laboratoire de botanique historique et palynologie. ura cnrs, marseille, 327 p. roglić, j. (1950): čepićko polje (polje čepić).– geografski glasnik, 11–12, 147–148. sandgren, p. & snowball, i. (2001): application of mineral magnetic techniques to palaeolimnology.– in: last, w.m. & smol, j.p. (eds.): tracking environmental change using lake sediments. kluwer academic publishers, dordrecht, 217–237. sangiorgi, f., capotondi, l., combourieu nebout, n., vigliotti, l., brinkhuis, h., giunta, s., lotter, a.f., morigi, c., negri, a. & reichart, g.-j. (2003): holocene seasonal sea-surface temperature variations in the southern adriatic sea inferred from a multiproxy approach.– journal of quaternary science, 18, 723–732. schmidt, r., muller, j., dresher-schneider, r., krisai, r., szeroczynska, k. & barić, a. (2000): changes in lake level and trophy at lake vrana, a large karstic lake on the island of cres (croatia), with respect to palaeoclimate and anthropogenic impacts during the last approx. 16,000 years.– journal of limnology, 59, 113–130. šikić, d. & polšak, a. (1973): osnovna geološka karta (ogk) sfrj 1:100000, tumač za list labin (basic geological map of sfry 1:100000, geology of the labin sheet).– institut za geološka istraživanja zagreb (1963), savezni geološki zavod, beograd, 55 p. škorić, a., mayer, b., vranković, a. & bašić, f. (1987): pedološka karta istre (soil map of istria).– institute for pedology at the faculty of agriculture, university of zagreb, 1st ed. zagreb. stockmarr, j. (1971): tablets with spores used in absolute pollen analysis.– pollen et spores, 13, 615–621. stuiver, m. & reimer, p. (1993): extended 14c database and revised calib radiocarbon calibration program.– radiocarbon, 35, 215–230. stuiver, m., reimer, p.j. & reimer, r.w. (2005): calib 5.0.– http://calib.qub.ac.uk whitlock, c. & larsen, c. (2001): charcoal as a fire proxy.– in: smol, j.p., birks, h.j.b. & last, w.m. (eds.): tracking environmental change using lake sediments. kluwer academic publishers, dordrecht, 75–97. wulf, s., kraml, m., brauer, a., keller, j. & negendank, j.f.w. (2004): tephrochronology of the 100 ka lacustrine sediment record of lago grande di monticchio (southern italy).– quaternary international, 122, 7–30. wunsam, s., schmidt, r. & muller, j. (1999): holocene lake development of two dalmatian lagoons (malo and veliko jezero, isle of mljet) in respect to changes in adriatic sea level and climate.– palaeogeography, palaeoclimatology, palaeoecology, 146, 251–281. manuscript received march 17, 2006. revised manuscript accepted november 24, 2006. coric.indd 31 � stjepan ćorić1, davor pavelić2, fred rögl3, oleg mandic3, sejfudin vrabac4, radovan avanić5, lazar jerković6 and alan vranjković2 ab stra ct the pannonian basin system (pbs) originated during the early miocene as a result of extensional processes between the alpine-carpathian and the dinaride orogenic belts. the paratethys sea fl ooded the new basins successively during the karpatian (late burdigalian, early miocene) and the early badenian (middle langhian, middle miocene). the north croatian basins (ncb) occupied the south-western margin of the pbs and the central paratethys sea. their initial marine fl ooding has until now been dated as karpatian in age. the transgression into the ncb invaded a lacustrine environment, representing the northern prolongation of the vast dinaride lake system extending southwards as far as the adriatic plate. we reinvestigate two sections from opposite margins of the nbs – from mt. medvednica in the west and from mt. požeška in the east, including the corresponding lowermost marine miocene deposits, in order to critically examine the karpatian datum. our new biostratigraphic data, integrating calcareous nannoplankton, planktic and benthic foraminifera, diatom and mollusc records, have substantially revised the previous interpretation. the presence of a calcareous nannoplankton assemblage of the nn5 zone and the planktic and benthic foraminifera of the regional lower lagenidae zone now place the transgression into the main early badenian transgressive pulse of central paratethys. consequently, the initial marine transgression correlates accurately with the middle part of the early badenian, which is more than 2 m.y. younger than the previously inferred datum, and at least 1 m.y. younger than the lower boundary of the badenian and the middle miocene, respectively. finally, the basal lacustrine infi ll of the ncb, previously dated as ottnangian (middle burdigalian, early miocene) and continuously grading into marine deposits, has also to be reconsidered as early badenian. keywords: pannonian basin system, north croatian basins, central paratethys, dinaride lake system, middle miocene, biostratigraphy 1 geological survey of austria, neulingg. 38, a-1030 wien, austria; (stjepan.coric@geologie.ac.at) 2 faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, hr-10000 zagreb, croatia; (dpavelic@rgn.hr, avranjko@rgn.hr) 3 geological-palaeontological department, natural history museum vienna, burgring 7, a-1010 wien, austria; (fred.roegl@nhm-wien.ac.at, oleg.mandic@nhm-wien.ac.at) 4 department of geology, faculty of mining, geology and civil engineering, university of tuzla, univerzitetska 2, bih-75000 tuzla, bosnia and herzegovina; (jvrabac@yahoo.com) 5 croatian geological survey, sachsova 2, p.o.box 268, hr-10000 zagreb, croatia; (radovan.avanic@hgi-cgs.hr) 6 faculty of sciences, university of podgorica, 81000 podgorica, montenegro; 202-444 rue poudriere, verdun, pq, h4g 3l9, canada; (doboj@estart.com) revised middle miocene datum for initial marine fl ooding of north croatian basins (pannonian basin system, central paratethys) geologia croatica 62/1 31–43 6 figs. 3 tabs. zagreb 2009 geologia croaticageologia croatica � geologia croatica geologia croatica 62/1 32 1. introduction north croatian basins (ncb) occupies the south-western margin of the pannonian basin system (fig. 1). their basal infi ll comprises freshwater sediments with fl uvial deposition, grading upwards into open lake deposits. the marine transgression intruded into the basins during the open lake phase, as suggested by an unchanged lithology across the transition. the boundary can be traced exclusively by the fi rst occurrence of marine fauna such as planktic and benthic foraminifera, indicating a salinity increase and an establish ed connection to the open sea. the age inference of the boundfi gu re 1: position of the north croatian basins in the pannonian basin system and the central paratethys sea (after pavelić et al., 2003). geologia croaticaćorić et al.: revised middle miocene datum for initial marine fl ooding of north croatian basins... 33 ary was determined solely on the interpretation of an impoverished, species-poor foraminiferal assemblage that has been originally regarded to correlate with karpatian assemblages from the northern and western central paratethys (šikić, 1968) (fig. 2). the lake deposits of the basal infi ll bear freshwater molluscs and ostracods absent from central paratethys and endemic to the dinaride neogene basins adjoining the ncb to the south (kochansky-devidé & slišković, 1978; kochansky-devidé, 1979; krstić et al., 2003). such a faunal composition of the basal parts of the ncb classifi es it with the palaeobiogeographic entity termed the dinaride lake system (dls) (krstić et al., 2003; harzhauser & mandic, 2008a, b). consequently dls includes the basal ncb together with the dinaride neogene basin fresh water deposits. the dating of the dls deposits is still subject to debate, especially due to a lack of the possibility for marine biostratigraphy (harzhauser & mandic, 2008a, b). the original correlation of the basal dls deposits with the ottnangian, is rooted in the interpretation of a small characean fl ora combined with their stratigraphic position directly below the formerly karpatian-dated deposits (šikić, 1968; kochansky-devidé & slišković, 1978). as will be shown by new data, the latter age inference turned out, however, to be incorrect. this paper critically examines the datum for the initial marine fl ooding of the ncb by means of integrative biostratigraphy, combining data on calcareous nannoplankton, foraminifera, molluscs and diatoms. this yields a more precise dating of the geodynamic history and rifting of the pannonian basin system (pbs). it also provides more insight into the palaeoenvironmental turnover in the south-western margin of the pbs resulting from the back-stepping of the dls and the landward progradation of the central paratethys sea. 2. history of investigation paul (1872, 1874) was the fi rst author to consider the basal freshwater deposits exposed at mt. medvednica n of zagreb, as temporal equivalents of the socka beds in ne slovenia. accordingly, he dated them as late oligocene. gorjanovićkramberger (1908), setting the initial milestone in the development of stratigraphic nomenclature for the north croatian basin deposits, followed pauls opinion. furthermore, he referred the superposed sediments, representing the initial marine transgression into the basins, to “early mediterranean” based on correlation with the eggenburgian strata of lower austria. finally, the younger marine strata on top of the latter deposits were dated as “younger mediterranean” (fig. 3). polić (1935) advocated the earlier correlation of freshwater deposits. based on the terrestrial macrofl ora he also suggested an oligocene age. kochansky-devidé (1944) provided the fi rst extensive biostratigraphic investigation on the macroand micro-fauna from marine deposits of the mt. medvednica environs. following the advance in regional stratigraphic nomenclature, she referred the “early mediterranean beds” to the burdigalian and the “younger mediterranean beds” to the helvetian and tortonian (note, however, the historical misuse of helvetian and tortonian in central paratethys as discussed by harzhauser et al., 2003). the intensive application of micropalaeontology for solving the stratigraphy of the ncb goes back to the 1960s. muldini-mamužić (1965) interpreted the ostracod record as support for the late oligocene age of the basal freshwater deposits. furthermore, the foraminifera seemed to indicate oligocene and burdigalian age for the initial marine beds. this was discussed in detail and substantially revised by šikić (1966, 1968), ultimately establishing the currently applied stratigraphic concept for the marine part of the ncb infi ll (pavelić et al., 2003). based on foraminiferal distributions, the lowermost marine beds were correlated with the karpatian (therein also termed the late helvetian) beds from the alpine carpathian foredeep and the western and northwestern pannonian basin system. furthermore, the underlying freshwater deposits bearing charophyta related to the upper freshwater molasse in bavaria are referred to as being helvetian s.str. and ottnangian in age (fig. 3). subsequently, the ottnangian correlation was adopted by kochansky-devidé & slišković (1978). they regarded the freshwater deposits of the ncb as the initial deposits of the “early lacustrine beds with congerians”, currently termed the dinaride lake system (krstić et al., 2003; harzhauser & mandic, 2008a, b). additionally, at fi gu re 2: oligocene−middle miocene chronostratigraphy of the central paratethys correlated to the standard geochronologic scale and the calcareous nonnoplankton zone of martini (1971) (simplifi ed, after piller et al., 2007). note the correlation of the middle miocene boundary after gradstein et al. (2004), defi ning it with the base of the palaeomagnetic chron c5br. in contrast, biostratigraphically, the middle miocene boundary is defi ned by the first appearance datum for the planktonic foraminiferal genus praeorbulina at 16.3 ma, as indicated by rögl et al. (2007). geologia croatica geologia croatica 62/1 34 mt. požeška, besides an ottnangian age a karpatian age has also been presumed for the upper part of the basal, lacustrine ncb deposits. this was based on the more advanced evoluti onary stage of the recorded dreissenid bivalves (kochansky devidé, 1979). given the above considerations, further palaeontological studies (as a part of a geological mapping effort), assigned the freshwater deposits to the lower helvetian, i.e. ottnangian, and the fi rst marine miocene sediments to the upper helvetian, i.e. karpatian (basch, 1983; jamičić et al., 1987, 1989; šparica & buzaljko, 1984; šparica et al., 1980). analyses of freshwater ostracods suggested a “middle miocene”, “helvetian” and karpatian age (sokač, 1987; sokač & krstić, 1987). more modern studies of terrestrial fl ora from the freshwater deposits indicated an ottnangian age (jungwirth & đerek, 2000), as did the mollusc associations (unionidae) from some localities in north croatia (žagar-sakač, 2003, 2004). complex sedimentological studies, micropalaeontological and palynological analyses dated these freshwater deposits as ottnangian, and the overlying marine sediments as karpatian on mounts požeška, mt. medvednica and mt. kalnik (avanić et al., 1995a, 1995b, 1995c; avanić, 1997; pavelić et al., 1998, 2001, 2003) (fig. 1). the same concept was applied in some regional works (lučić et al., 2001; pavelić, 2001, 2002, 2005; saftić et al., 2003). a list of important foraminifera and mollusc species of these croatian initial marine deposits, attributed to the karpatian, has been compiled by bajraktarević & pavelić (2003). more recent research on ostracods at several localities in north croatia indicates an ottnangian age for the freshwater deposits, a latest ottnangian to earliest karpatian age for the brackish-water sediments, and a karpatian age for the marine deposits (hajek-tadesse, 2006). based on these former results, all currently available reconstructions of the general evolution of central paratethys presumed erroneously a vast marine cover over the ncb during the karpatian (rögl & steininger, 1983; pavelić, 2001, 2005; bajraktarević & pavelić, 2003; rögl, 1996; kováč et al., 2003). only very few studies suggested a younger age for those freshwater and early marine deposits. one such example is the palynological-based study by krizmanić (1995). it related the bentonite clays containing remains of prodeinotherium bavaricum kaup on mt. moslavačka to the miocene climatic optimum, specifi cally correlating them with the time-span between the late karpatian and the early badenian. the overlying marine beds bearing foraminiferal associations of the upper lagenidae zone and the calcareous nannoplankton association of nn5 were previously dated as early badenian (bajraktarević, 1981; krizmanić, 1995). 3. geological setting the paratethys sea evolved in the early oligocene at the northern margin of the pre-mediterranean tethys ocean after alpine and dinaride orogenesis triggered the fi rst disturbance of water mass circulation patterns. this was followed by faunal extinction and endemic events (rögl, 1996). the distribution of the paratethys sea was mainly controlled by regional geodynamic evolution, resulting in a separate chronostratigraphic scale (fig. 2). the western paratethys of the alpine foredeep had already dried out in the early miocene. the central paratethys of the alpine-carpathian foredeep and the pannonian basin system disintegrated at the end of the middle miocene, giving rise to the late miocene lake pannon. the disintegration of eastern paratethys, today divided into the black sea, caspian sea and aral lakes, is still ongoing. the dinaride lake system (dls) developed during the early miocene on the land block located between central paratethys and the mediterranean tethys (mandic et al., 2008). it was inhabited by highly diversifi ed but almost completely endemic aquatic organisms such as molluscs or freshwater ostracods (krstić et al., 2003; harzhauser & mandic, 2008a, b). it represented, as shown by harzhauser & mandic (2008b), a separate palaeobiogeographic entity, different from any marginal environment of paratethys or of the mediterranean tethys. extending originally into the pannonian basin system, the dls retreated mainly due to paratethys sea transgression, becoming mainly restricted to the dinaride block. north croatia occupies the south-western margin of the pannonian basin system (pbs). the pbs, induced by extensional processes and rifting between the carpathian, alpine and dinaride chains, did not appear to exist prior to the fi gu re 3: milestones in the history of stratigra phic correlation of the north croatian basins. geologia croaticaćorić et al.: revised middle miocene datum for initial marine fl ooding of north croatian basins... 35 late early miocene (fig. 1). consequently, after the origin of paratethys and prior to the origin of the pbs, most of north croatia was represented by dry land, only occasionally developing freshwater wetland environments. the only exception was a small north-westernmost area of hrvatsko zagor je, mura and a marginal part of the drava basin (šimunić et al., 1990; jelen et al., 1998; pavelić et al., 2001). the e–w striking basin system became a central paratethys marine setting during the late oligocene or the earliest early miocene (pavelić et al., 2003). it then represented a side gulf of the transtethyan or north slovenian corridor connecting the paratethys sea with the mediterranean tethys ocean (rögl & steininger, 1983; rögl, 1996). the extensive north croatian basins are located southeast of the hrvatsko zagorje basin (fig. 1). the main constituents of the ncb are the sava, drava, bjelovar, požega and slavonia – srijem basins. following the former stratigraphic concept presented above, their evolution started in the early ottnangian. it was characterized by the predominance of coarse-grained siliciclastics from braided alluvial fans alternating with salina-type lakes under semi-arid climate conditions. after the end of this alluvial deposition, a freshwater lake formed in the late ottnangian, covering the whole area. it was characterized by fi ne-grained deposits such as limy silt, with high organic matter content and occurrences of pyroclastics (fig. 4). the shift from a semi-arid to humid climate contributed signifi cantly to the environmental turnover, substantially increasing the lake’s water volume (pavelić, 2001). the highly variable thickness of freshwater infi ll resulted from the palaeotopography and synsedimentary tectonic movements following the pbs rifting. its maximal thickness in marginal settings is about 450 m, but in basin depocentres it can be 2 to 3 times thicker (pavelić, 2001) (fig. 4). palaeomagnetic measurements of open lake deposits suggested a palaeogeographic position of the basin much further to the south than today, at an estimated palaeolatitude of about 300 (márton et al., 2005). the aquatic fossil assemblage accurately correlates these lake deposits with the oldest dls deposits (kochansky-devidé & slišković, 1978; kochansky-devidé, 1979). the gradual shift from a freshwater lacustrine to a marine environment without any lithological change can be traced throughout the north croatian basin (šikić, 1968; pavelić et al., 1998; pavelić, 2001; hajek-tadesse, 2006). since the depositional style remains unaltered, the recognition of a transitional boundary is based solely on the fi rst occurrences of the marine fossil assemblage. the succession from mt. medvednica represents the only known exception to that rule. a relative tectonic standstill reduced the subsidence rate so the transition from the lacustrine to marine environment is marked by a prograding clastic system and occurrence of coarse-grained deposits at the end of lacustrine deposition (pavelić et al., 2003). the environmental shift represents the initial marine ingression of central paratethys into the ncb, possibly refl ecting the reestablished paratethyan seaway to the mediterranean tethys along the slovenian corridor (rögl & steininger, 1983; rögl, 1996). the environment was characterized by inner shelf deposition of mostly lime silt with some coarse-grained intercalations. that marine phase ended with a sea-level fall, causing regression and deposition of sandstone. the maximal thickness of the ncb initial marine deposits is about 100 m in marginal settings, becoming thicker in basin depocentres (fig. 4). the overlying deposits are correlated with the lower and upper badenian based on foraminifera biostratigraphy. the architecture of these deposits refl ects the global sea-level fl uctuations during the middle miocene (haq, 1991; pavelić et al., 1998; pavelić, 2001, 2005; kováč et al., 2007). the characteristic sedimentological feature is enhanced carbonate production controlled by strong volcanism. this induced deposition of marls and limestones, intercalated with tephra beds. the end of the badenian is marked by a sealevel fall. the superposed sarmatian deposits already refl ect water chemistry events induced by progressive paratethyan isolation toward the end of the middle miocene (harzhauser & piller, 2007) (figs. 2 and 4). fi gu re 4: geological column of the lowermost north croatian basins infi ll (after pavelić, 2005), presenting the new stratigraphic interpretation. geologia croatica geologia croatica 62/1 36 4. results two sections representing the initial marine ncb deposits have been studied in detail. the čučerje section is located on the south-eastern slope of mt. medvednica, about 10 km ne of the city of zagreb. the sokolovac section is located on the southern slope of mt. papuk, about 1 km ssw of the village gornji vrhovci and 15 km nnw of the city of požega (fig. 1). the micropalaeontological samples comprised nannoplankton, diatoms, as well as planktonic and benthic foraminifera. additionally, for čučerje (fig. 1), the mollusc macrofauna from the coll. kochansky collection (croatian natural history museum) has been taxonomically revised and biostratigraphically reevaluated. 4.1. čučerje section (mt. medvednica) the čučerje section (fig. 5) shows a 42 m thick succession composed of 3 parasequences. the base of the section is at gps n 45° 53’ 45.5” e 16° 03’ 17.3”. for sample positions see fig. 5. the section was initially described by gorjanović kramberger (1923) as the “plaz” locality. kochansky-devidé (1944) described it as a large outcrop above the brook sw of podplaz and nw of the church of čučerje. she attributed its deposits, based on micro-and macrofaunal content, to the burdigalian, correlating them with the lower ottnangian beds from lower austria. although she originally noticed the conspicuous difference in faunal composition to the latter beds, in a subsequent publication she erroneously identifi ed one eggenburgian–ottnangian index fossil from the same locality (kochansky-devidé, 1956). šikić (1968) investigated foraminifers’ samples from that locality, attributing them to the karpatian. finally, avanić et al. (1995b) (see also avanić, 1997) provided a detailed description and interpretation of the depositional history for the section. although already correlating its middle and upper parts with the lower badenian, the authors still referred its lower parasequence to the karpatian. 4.1.1. sedimentology the lower parasequence is 15 m thick and represents a coarsening upward succession with marls at the base followed by predominantly silt deposition on top, intercalated with thin sandy layers. the coarsening has been interpreted as an environmental shift and shallowing, grading from shelf conditions up to the transitional zone close to the palaeoshore. the middle parasequence comprises partly bedded sands and sandstones representing a high-energy, shallow-water shoreface to nearshore depositional environment. the upper parasequence superposes a tephra layer at 36 m up of the section. it refl ects renewed deepening of the environment, comprising predominantly silt deposition. 4.1.2. calcareous nannoplankton biostratigraphy ten samples (fig. 5) have been investigated for the biostratigraphic evaluation of calcareous nannoplankton. the assemblages from this section are dominated by high percentages of helicoliths and small reticulofenestrids (table 1). helicoliths are represented by: helicosphaera carteri (wallich, 1877) kamptner (1954), h. walbersdorfensis müller (1974), h. wallichii (lohmann, 1902) boudreaux & hay (1969), and h. cf. waltrans theodoridis (1984), whereas the small reticulofenestrids are represented by reticulofenestra minuta roth (1970) and r. haqii backman (1978). the accompanying forms are: braarudosphaera bigelowii (gran & braarud, 1935) deflandre (1947), coccolithus pelagicus (wallich, 1877) schiller (1930), coronosphaera mediterranea (lohmann, 1902) gaarder (1977), cyclicargolithus fl oridanus (roth & hay, 1967) bukry (1971), perforocalcinela fusiformis bóna (1964), pontosphaera multipora (kamptner, 1948) roth (1970), reticulofenestra pseudoumbilica (gartner, 1967) gartner (1969), rhabdophaera sicca stradner (1963), sphenolithus heteromorphus deflandre (1953), s. moriformis (brönnimann & stradner, 1960) bramlette & wilcoxon (1967), triquetrorhabdulus milowii bukry (1971), and umbilicosphaera jafari müller (1974). the regular occurrence of the zonal marker sphenolithus heteromorphus deflandre (1953) and the absence of helicosphaera ampliaperta bramlette & wilcoxon (1967) in all investigated samples allow an identifi cation of nannoplankton zone nn5 (martini, 1971). 4.1.3. foraminifera biostratigraphy the foraminiferal associations were analyzed in samples hr 9, no. 1, no. 2, no. 3, no. 4, and hr 10 covering the lower parasequence and the lowermost 10 m of the section, respectively (fig. 5). see table 2 for the complete list of identifi ed species. the lowermost sample in section (hr 9) originated from grey silty micaceous shale. the rich assemblage is characterized by coarse-grained agglutinated foraminifera, typically badenian calcareous benthic species, and stratigraphically indifferent planktonic forms. the occurrences of the following microfossils are interesting, incertae sedis: bachmayerella laqueata rögl & franz, and bolboforma moravica redinger. benthic foraminifera species such as uvigerina grilli schmid, u. macrocarinata papp & turnovsky, u. uniseriata jedlitschka and pappina parkeri (karrer) are of stratigraphic importance. the planktonic assemblage consists mainly of fi ve-chambered globigerinids (e.g. globigerina ottnangiensis rögl) togeth er with several globigerinoides species (e.g. g. bisphe ricus todd). the uppermost studied sample hr 10, comprises gray-brown sediment residue, with cemented fi ne -grained quartz and silt and contains a mixed assemblage of shallow and deep-water species. stratigraphically important taxa occur together in the sample hr9 (table 2). the poor planktonic fauna is again dominated by small species such as globigerina praebulloides blow or tenuitellinata selleyi li, radford & banner. microfossils incertae sedis bachmayerella tenuis rögl & franz and bolboforma sp. are also present. the lower part of the section represents a rather deep, probably outer shelf environment as indicated by the presence of agglutinated foraminiferal taxa (bathysiphon, hygeologia croaticaćorić et al.: revised middle miocene datum for initial marine fl ooding of north croatian basins... 37 perammina, reophax, reticulophragmium, cyclammina). a larger sediment input from shallow water is documented by the occurrence of miliolids, elphidiids, ammonia, pararotalia, and amphistegina. asterigerinata planorbis (d’orbigny), ammonia viennensis (d’orbigny), cibicidoides ungerianus ungerianus (d’orbigny), and amphistegina mammilla (fichtel & moll) and characterized by a large number of individuals. biostratigraphically, this part of the section belongs to the early badenian, corresponding with the lower lagenifi gu re 5: studied sections with indicated sample positions. geologia croatica geologia croatica 62/1 38 dae zone of the vienna basin. in sample no. 3 the early badenian is explicitly documented by the planktonic species orbulina suturalis brönnimann. for regional stratigraphic correlation with the lower lagenidae zone (comp. rögl et al., 2002; spezzaferri et al., 2004), the key-species discovered in the čučerje samples are: uvigerina macrocarinata papp & turnovsky, pseudogaudryina lapugyensis (cushman), p. sturi (karrer), and amphistegina mammilla (fichtel & moll). the microfossil bolboforma moravica redinger is also a typical species of the early badenian (spiegler & rögl, 1992). 4.1.4. mollusc biostratigraphy this review is based on fi eld observations combined with re-examination of the collection of kochansky-devidé housed at the department of geology and palaeontology of the croatian natural history museum in zagreb. the collection includes specimens originally studied and published by kochansky-devidé (1944, 1956). the lowermost marine parasequence bears the nautilid aturia aturi, indicating an open marine connection of the depositional environment. the shells of the neritic, offshore-living nautilus can fl oat for thousands of kilometres after the animal dies, drifting on surface currents, before settling to the bottom or becoming washed ashore. aturia aturi (basterot) was present in paratethys throughout the lower and middle miocene (lukeneder & harz hauser, 2002). the second sandy parasequence comprises a leached macrofauna with aragonite representatives traced exclusively by moulds and steinkerns (endocasts). the calcite shells, in contrast, are fairly well preserved, and with the single exception of calcifi ed nototeredo norvegica (splengler) siphonal tubes, belong to pteriomorphian bivalves. the following taxa occur: crassadoma multistriata (poli), aequi pecten macrotis (sowerby), a. scabrellus (lamarck), oppenheimopecten revolutus (michelotti), flabellipecten solarium (lamarck), and anomia ephippium brocchi in bronn. all except anomia ephippium brocchi are scallops. the absence of ostreid shells is conspicuous. note the erro neous identifi cation of flabellipecten solarium (lamarck) as pecten pseudobeudanti deperet & roman by kochansky-devidé (1956). the specimen reinvestigated at the croatian natural history museum is a single right valve with a length of 10 cm, labeled with the numbers 667 table 1: nannofossil distribution (following odp terminology) in samples from the čučerje section. samples pr es er va tio n ab un da nc e br aa ru do sp ha er a bi ge lo w ii (g ra n & b ra a ru d , 1 93 5) d ef la n d re (1 94 7) co cc ol ith us m io pe la gi cu s b u kr y (1 97 1) co cc ol ith us p el ag ic us (w a ll ic h , 1 87 7) s ch il le r (1 93 0) co ro no cy cl us n ite sc en s ( ka m pt n er , 1 96 3) b ra m le tt e & w il co xo n (1 96 7) co ro no sp ha er a m ed ite rra ne a (l o h m a n n , 1 90 2) g a a rd er (1 97 7) cy cl ic ar go lit hu s fl o rid an us (r o th & h ay , 1 96 7) b uk ry (1 97 1) h el ic os ph ae ra ca rt er i ( w a ll ic h , 1 87 7) k am pt n er (1 95 4) h el ic os ph ae ra w al be rs do rf en sis m ü ll er (1 97 4) h el ic os ph ae ra c f. w al tra ns t h eo d o ri d is (1 98 4) h el ic os ph ae ra w al ic hi i ( lo h m a n n , 1 90 2) b o u d re au x & h ay (1 96 9) pe rf or oc al ci ne la fu sif or m is bó n a (1 96 4) po nt os ph ae ra m ul tip or a (k a m pt n er , 1 94 8) r o th (1 97 0) po nt os ph ae ra sp . re tic ul of en es tra h aq ii ba ck m a n (1 97 8) re tic ul of en es tra m in ut a ro th (1 97 0) re tic ul of en es tra p se ud ou m bi lic a (g a rt n er , 1 96 7) g a rt n er (1 96 9) rh ab do sp ha er a sic ca s tr a d n er (1 96 3) sp he no lit hu s h et er om or ph us d ef la n d re (1 95 3) sp he no lit hu s m or ifo rm is (b rö n n im an n & s tr ad n er , 1 96 0) br am le tt e & w il co xo n (1 96 7) tr iq ue tr or ha bd ul us m ilo w ii bu kr y (1 97 1) u m bi lic os ph ae ra ja fa ri m ü ll er (1 97 4) re w or ke d m ic ul a de cu ss at a ve ks h in a (1 95 9) w at zn au er ia b ar ne sa e (b la ck , 1 95 9) p er ch -n ie ls en (1 96 8) čučerje 8 g/m c r r f r r f r r r r r f c r čučerje 7 g a r r r f/c r r r r r f c r r čučerje 6 g c r r r f r r r r f c r r f čučerje 5 g c f r f r r r r f c r r r r hr 10 g c r r r f/c r r r r f c f r r čučerje 4 g c f r f r r r r f c r r r r čučerje 3 g c f r f r r r r f c r r r r čučerje 2 g c f r f r r r r f c r r r r čučerje 1 g a r r r f/c r r r f c r r r r hr 9 g c r r r f/c r r r c r geologia croaticaćorić et al.: revised middle miocene datum for initial marine fl ooding of north croatian basins... 39 and 692. its large size, high initial shell convexity, 19 massive, and subquadrangular ribs refers it accurately to flabellipecten solarium (lamarck). the latter beds were original ly correlated with the ottnangian zogelsdorf formation environs in lower austria. flabellipecten solarium (lamarck) however is restricted in the central paratethys to badenian deposits. the topmost parasequence, starting with a tephra bed and continuing with fi ne clastic deposition, contains a single, previously absent pectinid species, the cementing hinnites brussoni (de serres) a long-lived taxon that occurs in central paratethys throughout the lower and middle miocene. 4.2. sokolovac section (mt. papuk) the section follows a n–s striking brook and is today largely covered by vegetation. the gps position of the lowermost partial outcrop (–45m of the section) is n 45°27’27.8” e 17°33’51.4”. the second outcrop, located about 144 m north of the fi rst one, represents the partial section between 0 and 6 m. its gps position is n 45°27’32.7” e17°33’51.6”. the bedding orientation measured was 056/25. the third partial outcrop is located about 26 m north of the second one, representing a partial section around 15 m. its gps position is n 45°27’33.4” e17°33’51.9”. for sample positions see fig. 5. the section was originally studied by pavelić et al. (1998) referring it largely to the karpatian based on foraminifera biostratigraphy. 4.2.1. sedimentology the succession is one single coarsening upward sequence. the lowermost part is dominated by silt and siltones intercalated with sandstone layers bearing a well-preserved fossil leaf assemblage, representing freshwater, open lake deposition. following a covered interval of about 45 m very similar silts with some sandy interlayers outcrop. they represent a transition from lacustrine to marine conditions. at 4 m along this part of the section (fig. 5) a prominent sand bed occurs, representing a subaqueous debris fl ow event. sand deposition starts at about 15 m along the section, marking the onset of shallow-water environmental conditions. the top of the section is marked fi nally by trough cross-bedded sands, indicating a shoreface depositional regime. 4.2.2. calcareous nannoplankton and diatom biostratigraphy nine samples were investigated for calcareous nannoplankton and diatoms from the sokolovac section (poljanska) (table 3). only sample sokolovac 7 contains a rich and well-preserved nannofl ora with coccolithus pelagicus (wallich, 1877) schiller (1930), helicosphaera carteri (wallich, 1877) kamptner (1954), h. walbersdorfensis müller (1974), perforocalcinela fusiformis, reticulofenestra gelida (geitzenauer, 1972) backman (1978), r. haqii backman (1978), r. minuta roth (1970) and r. pseudoumbilica (gartner, 1967) gartner (1969). samples from the lower part of the section mostly lack calcareous nannoplankton. only samples sokolovac 0 and sokolovac 1 contain rare coccolithus pelagicus (wallich, 1877) schiller (1930), h. carteri (wallich, 1877) kamptner (1954), r. haqii backman (1978), r. minuta roth (1970) and umbilicosphaera jafari müller (1974). smear slides from samples sokolovac 0, 1, 2 and 7 contain table 2: distribution of benthic and planktic foraminifera from the čučerje section. samples te xt ul ar ia sp . ps eu do ga ud ry in a la pu gy en sis (c u sh m a n ) ps eu do ga ud ry in a st ur i ( ka rr er ) tr ilo cu lin a sp . q ui nq ue lo cu lin a cf . a kn er ia na d ’o rb ig n y sp iro lo cu lin a ca na lic ul at a d ’o rb ig n y le nt ic ul in a in or na ta (d ’o rb ig n y) g lo bu lin a gi bb a d ’o rb ig n y g ut tu lin a co m m un is (d ’o rb ig n y) g la nd ul in a ov ul a d ‘o rb ig n y bo liv in a an tiq ua d ’o rb ig n y bo liv in a sp . fu rs en ko in a ac ut a (d ’o rb ig n y) bu lim in a su bu la ta c u sh m a n & p a rk er bu lim in a cf . s ub ul at a cu sh m a n & p a rk er u vi ge rin a ac um in at a h o si u s u vi ge rin a cf . m ac ro ca rin at a pa pp & t u rn o vs ky u vi ge rin a cf . p yg m oi de s p a pp & t u rn o vs ky u vi ge rin a gr ill i s ch m id , u vi ge rin a m ac ro ca rin at a pa pp & t u rn o vs ky u vi ge rin a sp . u vi ge rin a un ise ria ta je d li ts ch ka pa pp in a pa rk er i ( ka rr er ) ci bi ci do id es u ng er ia nu s u ng er ia nu s ( d ’o rb ig n y) as te rig er in at a pl an or bi s ( d ’o rb ig n y) am ph ist eg in a m am m ill a (f ic h te l & m o ll ) m el on is po m pi lio id es (f ic h te l & m o ll ) ch ilo st om el la o vo id ea r eu ss al ab am in a ar m el la e po pe sc u sv ra tk in a ci ch ai p o pe sc u am m on ia v ie nn en sis (d ’o rb ig n y) el ph id iu m c f. ru go su m (d ’o rb ig n y) el ph id iu m fi ch te lli an um (d ’o rb ig n y) el ph id iu m fl ex uo su m (d ’o rb ig n y) g lo bi ge rin ita u vu la (e h re n be rg ) te nu ite lli na ta se lle yi l i, ra d fo rd & b a n n er g lo bi ge rin a ot tn an gi en sis r ö g l g lo bi ge rin a pr ae bu llo id es b lo w g lo bi ge rin a su bc re ta ce a lo m n ic ki g lo bi ge rin a ta rc ha ne ns is su bb o ti n a & c h u tz ie va g lo bi ge rin a cf . t ar ch an en sis s u bb o ti n a & c h u tz ie va g lo bi ge rin a sp . g lo bi ge rin oi de s b isp he ric us t o d d g lo bi ge rin oi de s q ua dr ilo ba tu s ( d ’o rb ig n y) g lo bi ge rin oi de s t ril ob us (r eu ss ) o rb ul in a su tu ra lis b rö n n im a n n hr 10 x x x x x x x x no. 4 x x x x x x x x x x no. 3 x x x x x x x x x x x x x no. 2 x x x x x x x no.1 x x x x x x x x x x x x x x x x hr 9 x x x x x x x x x x x x x x geologia croatica geologia croatica 62/1 40 fossil resting spore determined as truncatulus tortonicus (hajos) suto. although the zonal marker sphenolithus heteromorphus deflandre (1953) was not identifi ed in the samples containing nannofossils (sokolovac 0, 1 and 7) the composition of the nannoplankton assemblage dominated by reticulofenestra min uta indicates nannoplankton zone nn5. this biostratigraphic contribution can be confi rmed by the presence of reticulofenestra pseudoumbilica with diameters from 5 to 7µm. truncatulus tortonicus (hajos) suto is related to the marine planktonic diatoms chaetoceros ehrenberg, described by hajós (1986) from the hungarian middle miocene diatomite (locality szurdokpüspöki). it occurs from the early middle miocene diatom zone npd 4b to the upper late pliocene zone npd 9. the genus chatetoceros is an important marine producer in nearshore upwelling regions (suto, 2006). 4.2.3. foraminifera biostratigraphy three samples from the lower part of the section have been studied. the samples no. 0 (54) and no. 1 (54) lacked microfossils. sample no. 7 (55) contained a poorly preserved, but diverse assemblage of 45 species. with the exception of one specimen of cassigerinella globulosa (egger), only benthic species are present, dominated by small agglutinated forms. calcifi ed casts of pteropods (spirialis) are frequent. the faunal assemblage is characteristic for the karpatian/badenian transition. uvigerina macrocarinata papp & turnovsky is a marker species for the early badenian (lower lagenidae zone). 5. discussion and conclusion this study revises the age for the lowermost marine beds of the north croatian basins. these originally karpatian-dated sediments are now provided with a new age framework. accordingly, our results based on integrative biostratigraphic studies prove a middle miocene, early badenian age. all investigated samples from čučerje and the uppermost sample from sokolovac indicate nannoplankton zone nn5, with the zonal marker species sphenolithus heteromorphus deflandre (1953). nannoplankton assemblages with blooms of helicoliths and small reticulofenestrids indicate a nearshore, nutrient-rich environment. this coincides with the results from the benthic and planktic foraminiferal assemblages. uvigerina macrocarinata papp & turn ovsky, pseudogaudryina lapugyensis (cushman), p. sturi (karrer), amphistegina mammilla (fichtel & moll), and orbulina suturalis brönnimann characterize the lower lagenidae zone of the badenian in the vienna and styrian basins (rögl et al., 2007). additionally, the presence of the microfossil bolboforma moravica redinger, together with the mass occurrence of the planktonic gastropod “spirialis”, confi rm the early badenian age. the diatom fl ora with truncatulus tortonicus (hajos) suto determined from the transitional part of the sokolovac section suggests a badenian age. the pectinid bivalve flabellipecten solarium (lamarck) from the čučerje section also indicates a badenian age. the assemblages point to a badenian age correlated with the upper part of the lower lagenidae zone (fig. 6). the fi rst occurrence of orbulina suturalis brönnimann, dated at 14.74 ma and found at about 5 m up the čučerje table 3: nannofossil distribution (following odp terminology) in samples from the sokolovac section. samples pr es er va tio n ab un da nc e co cc ol ith us p el ag ic us (w a ll ic h , 1 87 7) s ch il le r (1 93 0) h el ic os ph ae ra ca rt er i (w a ll ic h , 1 87 7) k am pt n er (1 95 4) h el ic os ph ae ra w al be rs do rf en sis m ü ll er (1 97 4) pe rf or oc al ci ne la fu sif or m is bó n a (1 96 4) re tic ul of en es tra g el id a (g ei tz en au er , 1 97 2) b ac km a n (1 97 8) re tic ul of en es tra h aq ii ba ck m a n (1 97 8) re tic ul of en es tra m in ut a ro th (1 97 0) re tic ul of en es tra p se ud ou m bi lic a (g a rt n er , 1 96 7) g a rt n er (1 96 9) u m bi lic os ph ae ra ja fa ri m ü ll er (1 97 4) re w or ke d w at zn au er ia b ar ne sa e (b la ck , 1 95 9) p er ch -n ie ls en (1 96 8) sokolovac 7 g c f r r r r r c r sokolovac 6 barren sokolovac 5 barren sokolovac 4 barren sokolovac 3 barren sokolovac 2 barren sokolovac 1 g f f f r c r sokolovac 0 p r x x x x sokolovac -1 barren geologia croaticaćorić et al.: revised middle miocene datum for initial marine fl ooding of north croatian basins... 41 section, demonstrates a much higher stratigraphic level for the succession than previously considered. the depositional evolution in both sections suggests a position above the maximal fl ooding surface and within the high stand system tract, which can be biostratigraphically correlated with the 3rd order sequence tb 2.4 (fig. 6). the age of the marine transgression lies within the lower part of nannoplankton zone nn5, having its base at 14.91 ma. this places the initial marine sedimentation in the ncb at least 1 m.y. above the middle miocene lower boundary. the position of the earlymiddle miocene boundary is currently under discussion. hence, gradstein et al. (2004) placed it on top of the palaeomagnetic chron c5cn, whereas its biostratigraphic defi nition relates to the first appearance datum of the planktic foraminferal genus praeorbulina (see lourens et al., 2004). the transition from the lake deposits to the marine environment was observed in the sokolovac section. there is no sedimentological break between the lacustrine and marine deposits, suggesting continuous sedimentation throughout the lower badenian. based on a time interval of 1 m.y., the resulting mean sedimentation rate for freshwater sedimentation would be 0.45 mm/y. surprisingly the present study suggests a distinctly young er age for the neogene sedimentation in the north croatian basins than formerly considered. probably the complete depositional cycle of its lower basinal infi ll, comprising the lacustrine and the early marine sediments, belongs to the middle miocene, badenian stage. this completely changes the palaeogeographic picture for the south-western part of the pannonian basin system. instead of ottnangian freshwater beds and a karpatian marine transgression, aquatic environments existed solely during the badenian. acknowledgement the study was funded by ministry of science, education and sports of the republic of croatia, project: ‘neogene terrestrial environments of the pannonian basin and karst region’ no. 195-1951293-2703, and by the austrian fwf project p18519-b17: ‘mollusc evo lu tion of the neogene dinaride lake system’. om is highly in debted to zlata jurišićpolšak (croatian natural history museum, zagreb) for facilitating ac cess to collection kochansky-devidé. the authors are indebt ed to mathias harzhauser (nhm vienna) and zlatan bajrak tarević (pmf zagreb) for critically reviewing the manuscript. references avanić, r. (1997): analiza facijesa srednjeg miocena na jugoistočnim padinama medvednice [facies analysis of middle miocene on south ern slopes of mt. medvednica − in croatian].– unpubl. msc thesis, university of zagreb, zagreb, 54 p. avanić, r., kovačić, m., pavelić, d., šimunić, al., miknić, m. & vrsaljko, d. (1995a): kongerijski vapnenci i klastiti otnanga – geološki stup vidovec–2 [ottnangian congeria-limestone and clastics – geological column vidovec–2 – in croatian].– in: šikić, k. (ed.): geološki vodič medvednice, inst. za geol. istraž, ina – industrija nafte d.d., zagreb, 154. avanić, r., pavelić, d., miknić, m., brkić, m. & šimunić, al. (1995b): karpatsko–donjobadenske naslage čučerja [karpatian–lower badenian beds from čučerje – in croatian].– in: šikić, k. (ed.): geološki vodič medvednice. inst. za geol. istraž., ina – industrija nafte d.d., zagreb, 156–158. fi gu re 6: stratigraphic time scale and correlation of investigated sections (modifi ed after rögl et al., 2007). geologia croatica geologia croatica 62/1 42 avanić, r., pavelić, d., vrsaljko, d., šimunić, al., miknić, m., hajek-tadesse, v. & jerinić, g. (1995c): otnanški klastiti planine [ottnangian clastics from planina – in croatian].– in: šikić, k. (ed.): geološki vodič medvednice. inst. za geol. istraž., ina – industrija nafte d.d., zagreb, 164–168. bajraktarević, z. (1981): donji baden (donji “torton”) južnog dijela moslavačke gore [early badenian (early “tortonian”) of southern part of mt. moslavačka – in croatian].– geol. vjesnik, 34, 9–13. bajraktarević, z. & pavelić, d. (2003): the karpatian in croatia.– in: brzobohatý, r., cicha, i., kováč, m. & rögl, f. (eds.): the karpatian. a lower miocene stage of the central paratethys. masaryk university, brno, 141–144. basch, o. (1983): osnovna geološka karta sfrj 1: 100000. tumač za list ivanić-grad [basic geological map of sfry 1:100000, geology of the ivanić-grad sheet − in croatian].– geol. zavod, zagreb, sav. geol. zavod, beograd, 66 p. gorjanović-kramberger, d. (1908): geologijska prijegledna karta kraljevine hrvatske – slavonije. tumač geologijskoj karti zagreb [geological descriptive map of the kingdom of croatia – slavonia, geology for geological map of zagreb − in croatian].– nakl. kralj. zemalj. vlade, odjel za unutar. poslove, zagreb, 75 p. gorjanović-kramberger, d. (1923): der bruchrand des zagreber gebirges zwischen podsused und zagreb und seine bedeutung zur heranbildung der zagreber terasse.– glasn. hrv. prirodosl. društva, zagreb, 34, 3–15. gradstein, f.m., ogg, j.g. & smith, a.g. (2004): a geologic time scale 2004. cambridge university press, cambridge, uk, 610 p. hajek-tadesse, v. (2006): miocenski ostrakodi sjeverne hrvatske [miocene ostracods of northern croatia – in croatian].– unpubl. phd thesis, university of zagreb, zagreb,179 p. hajós, m (1986): stratigraphy of hungary's miocene diatomaceous earth deposits.– geol. hung., 49, 1–401. haq, b. (1991): sequence stratigraphy, sea-level change, and signifi cance for deep sea.– spec. publ. int. assoc. sediment., blackwell, 12, 3–39. harzhauser, m. & mandic, o. (2008a): neogene dreissenids in central europe – exploring the limits.– in: van der velde, g., rajagopal, s. & bij de vaat, a. (eds.): zebra mussels in europe. (in press). harzhauser, m. & mandic, o. (2008b): neogene lake systems of central and south-eastern europe: faunal diversity, gradients and interrelations.– palaeogeogr., palaeoclimatol., palaeoecol., 260, 417–434. harzhauser, m., mandic, o. & zuschin, m. (2003): changes in paratethyan marine molluscs at the early/middle miocene transition: diversity, palaeogeography and palaeoclimate.– acta geol. pol. 53/4, 323–339. harzhauser, m. & piller, w.e. (2007): benchmark data of a changing sea – palaeogeography, palaeobiogeography and events in the central paratethys during the miocene.– palaeogeogr., palaeoclimatol., palaeoecol., 253, 8–31. jamičić, d., brkić, m., crnko, j. & vragović, m. (1987): osnovna geološka karta sfrj 1:100000. tumač za list orahovica [basic geological map of sfry 1:100000, geology of the orahovica sheet − in croatian].– geol. zavod, zagreb, sav. geol. zavod, beograd, 72 p. jamičić, d., vragović, m. & matičec, d. (1989): osnovna geološka karta sfrj 1:100000. tumač za list daruvar [basic geological map of sfry 1:100000, geology of the daruvar sheet − in croatian].– geol. zavod, zagreb, sav. geol. zavod, beograd, 55 p. jelen, b., márton, e., fodor, l., báldi, m., čar, j., rifelj, h., skaberne, d. & vrabec, m. (1998): palaeomagnetic, tectonic and stratigraphic correlation of tertiary formations in slovenia and hungary along the periadriatic and mid-hungarian tectonic zone (preliminary communication).– geologija, ljubljana, 40, 325–331. jungwirth, e. & đerek, t. (2000): osobitosti paleofl ore lokaliteta planina [some characteristics of palaeofl ora of the planina locality – in croatian].– in: vlahović, i. & biondić, r. (eds.): sec. croat. geol. cong., cavtat–dubrovnik, 17–20.05.2000, proceedings, institute of geology, zagreb, zagreb, 225–229. kochansky-devidé, v. (1944): fauna marinskog miocena južnog pobočja medvednice (zagrebačke gore) [fauna of marine miocene of southern fl anks of mt. medvednica (mt. zagrebačka) – in croatian].– vjestnik hrv. drž. geol. zav. i hrv. drž. geol. muz., zagreb, 2–3, 171–280. kochansky-devidé, v. (1956): o fauni marinskog miocena i o tortonskom “šliru” medvednice (zagrebačka gora).– geol. vjesnik, 10, 39–50. kochansky-devidé, v. (1979): srednjomiocenske kongerijske nasla ge požeške gore [middle miocene congeria – beds of mt. požeška – in croatian].– geol. vjesnik, 31, 69–72. kochansky-devidé, v. & slišković, t. (1978): miocenske kongerije hrvatske, bosne i hercegovine [miocene congerias of croatia, bosnia and herzegovina – in croatian].– palaeont. jugosl., zagreb, 19, 1–98. kováč, m., andreyeva-grigorovich, a., bajraktarević, z., brzobohatý, r., filipescu, s., fodor, l., harzhauser, m., nagymarosy, a., oszczypko, n., pavelić, d., rögl, f., saftić, b., sliva, ľ. & studencka, b. (2007): badenian evolution of the central paratethys sea: palaeogeography, climate and eustatic sea level changes.– geol. carpat., 58, 579–606. kováč, m., andreyeva-grigorovich, a., brzobohatý, r., fodor, l., harzhauser, m., oszcypko, n., pavelić, d., rögl, f., saftić, b., sliva, ľ. & stránik, z. (2003): karpatian palaeogeography, tectonics and eustatic changes.– in: brzobohatý, r., cicha, i., kováč, m. & rögl, f. (eds.): the karpatian. a lower miocene stage of the central paratethys, masaryk university, brno, 49–72. krizmanić, k. (1995): palynology of the miocene bentonite from gornja jelenska (mt. moslavačka gora, croatia).– geol. croat., 48, 147–154. krstić, n., savić, lj., jovanović, g. & bodor, e. (2003): low er miocene lakes of the balkan land.– acta geol. hung., 46, 291–299. lourens, l., hilgen, f., shackleton, n.j., laskar, j. & wilson, j. (2004): the neogene period.– in: gradstein, f.m., ogg, j.g. & smith, a.g. (eds.): a geologic time scale 2004., cambridge university press, cambridge, uk, 409–440. lučić, d., saftić, b., krizmanić, k., prelogović, e., britvić, v., mesić, i. & tadej, j. (2001): the neogene evolution and hydrocarbon potential of the pannonian basin in croatia.– mar. petrol. geol., 18, 133–147. lukeneder, a. & harzhauser, m. (2002): shell accumulations of the nautilidae aturia (aturia) aturi in the lower miocene paratethys.– in: summesberger, h., histon, k. & daurer, a. (eds.): cephalopods – present and past. abhandlungen der geologischen bundesanstalt, 57, 459–466. mandic, o., pavelić, d., harzhauser, m., zupanič, j., reischenbacher, d., sachsenhofer, r.f., tadej, n. & vranjković, a. (2008): depositional history of the miocene lake sinj (dinaride lake system, croatia): a long-lived hard water lake in a pull-apart tectonic setting.– j. palaeolimnol., doi: 10.1007/s10933-008-9235-1 martini, e. (1971): standard tertiary and quartenary calcareous nannoplankton zonation.– proceedings of the ii planktonic conference., ed. tecnoscienza, roma, 739–785. márton, e., pavelić, d., tomljenović, b., márton, p. & avanić, r. (2005): palaeomagnetic investigations in the croatian part of the pannonian basin: a review.– acta geol. hung., 48, 225– 233. geologia croaticaćorić et al.: revised middle miocene datum for initial marine fl ooding of north croatian basins... 43 muldini-mamužić, s. (1965): rezultati mikrofaunističkog istraživanja oligocenskih i miocenskih naslaga panonske kotline [results of microfaunistic study of the oligocene and miocene beds of the požega valley – in croatian].– acta geol., 5, (prir. istraž. jugosl. akad. znan. umjet., 35), 289–312. paul, m. (1872): die kohlenablagerungen bei agram und brod.– verh. geol. reichsanst., wien, 6. paul, m. (1874): die braunkohlen – ablagerungen von croatien und slavonien.– jahrb. geol. reichsanst., 24/3. pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.– basin res., 13, 359–376. pavelić, d. (2002): the south-western boundary of central paratethys.– geol. croat., 55, 83–92. pavelić, d. (2005): cyclicity in the evolution of the neogene north croatian basin (pannonian basin system).– in: mabesoone, j.m. & neumann, v.h. (eds.): cyclic development of sedimentary basins. dev. sedim., elsevier, 57, 273–283. pavelić, d., avanić, r., bakrač, k. & vrsaljko, d. (2001): early miocene braided river and lacustrine sedimentation in the kalnik mountain area (pannonian basin system, nw croatia).– geol. carpat., 52, 375–386. pavelić, d., avanić, r., kovačić, m., vrsaljko, d. & miknić, m. (2003): an outline of the evolution of the croatian part of the pannonian basin system.– in: vlahović, i. & tišljar, j. (eds.): evolution of depositional environments from the palaeozoic to the quaternary in the karst dinarides and the pannonian basin. 22nd ias meeting of sedimentology, opatija – sept. 17–19, 2003, field trip guidebook, zagreb, 155–161. pavelić, d., miknić, m. & sarkotić šlat, m. (1998): early to middle miocene facies succession in lacustrine and marine environments on the southwestern margin of the pannonian basin system.– geol. carpat., 49, 433–443. piller, w., harzhauser, m. & mandic, o. (2007): miocene central paratethys stratigraphy – current status and future directions.– stratigraphy, 4, 151–168. polić, a. (1935): o oligocenu i njegovoj fl ori kod planine u zagrebačkoj gori [about the oliocene and it's fl ora by planina on mt. zagrebačka – in croatian].– rad jugosl. akad. znan. umjetn., zagreb, 251, 61–90. rögl, f. (1996): stratigraphic correlation of the paratethys oligocene and miocene.– mitt. ges. bergbaustud. österr., 41, 65–73. rögl, f., ćorić, s., hohenegger, j., pervesler, p., roetzel, r., scholger, r., spezzaferri, s. & stingl, k. (2007): cyclostratigraphy and transgressions at the early/middle miocene (karpatian/badenian) boundary in the austrian neogene basins (central paratethys).– scripta fac. sci. natur. univ. masarykianae brunensis, ser. geology, brno, 36, 7–13. rögl, f., spezzaferri, s. & ćorić, s. (2002): micropalaeontology and biostratigraphy of the karpatian-badenian transition (early-middle miocene boundary) in austria (central paratethys).– courier forsch. inst. senckenberg, frankfurt a. m., 237, 47–67. rögl, f. & steininger, f.-f. (1983): vom zerfall der tethys zu mediterran und paratethys. die neogene palaeogeographie und palinspastik des zirkum-mediterranen raumes.– ann. naturhist. mus. wien, 85, 135–163. saftić, b., velić, j., sztanó, o., juhász, g. & ivković, ž. (2003): tertiary subsurface facies, source rocks and hydrocarbon reservoires in the sw part of the pannonian basin (northern croatia and south-western hungary).– geol. croat., 56, 101–122. sokač, a. (1987): pannoninotus n. gen. (crustacea, ostracoda) from the middle miocene of bjelanovac (psunj mountain, north croatia).– geol. vjesnik, 40, 39–44. sokač, a. & krstić, n. (1987): ostracod fauna of some non-marine neogene basins in yugoslavia.– geol. vjesnik, 40, 45–52. spezzaferri, s., rögl, f., ćorić, s. & hohenegger, j. (2004): palaeoenvironmental changes and agglutinated foraminifera across the karpatian/badenian (early/middle miocene) boundary in the styrian basin.– in: bubik, m. & kaminski, m.a. (eds.): proceedings of the 6th international workshop on agglutinated foraminifera (prague, czech republik, sept. 1–7, 2001). grzybowski foun dation spec. publ., krakow, 8, 423–459. spiegler, d. & rögl, f. (1992): bolboforma (protophyta, incertae sedis) im oligozän und miozän des mediterran und der zentralen paratethys.– annalen naturhist. mus. wien, 95a, 59–95. suto, i. (2006): truncatulus gen. nov., a new fossil resting spore morphogenus related to the marine diatom genus chaetoceros (bacillariophyceae).– phycologia, 45/5, 585–601. šikić, l. (1966): new concepts on the age of the hitherto existing burdigalian and upper oligocene deposits in the zagrebačka gora mountain.– bull. sci. cons. acad. yougosl., zagreb, (a), 11/1–12, 246–247. šikić, l. (1968): stratigrafi ja miocena sjeveroistočnog dijela medvednice na osnovu faune foraminifera [stratigraphy of the miocene based on foraminifera fauna – in croatian].– geol. vjesnik, 21, 213–227. šimunić, al., avanić, r., & šimunić, an. (1990): “maceljski pješčenjaci” i vulkanizam zapadnog dijela hrvatskog zagorja (hrvatska, jugoslavija) [“macelj sandstones” and volcanism in the west ern part of hrvatsko zagorje (croatia, yugoslavia) – in croatian].– rad jazu, zagreb, 449, 179–194. šparica, m. & buzaljko, r. (1984): geološka karta sfrj 1:100000. tumač za list nova gradiška [basic geological map of sfry 1:100000, geology of the nova gradiška sheet – in croatian].– geol. zavod, zagreb, inst. za geologiju, sarajevo, sav. geol. zavod, beograd, 54 p. šparica, m., juriša, m., crnko, j., šimunić, an., jova nović, č. & živanović, d. (1980): osnovna geološka karta sfrj 1:100000. tumač za list nova kapela [basic geological map of sfry 1:100000 geology of the nova kapela sheet − in croatian].– inst. za geol. istraž., zagreb, inst. za geol., sarajevo, sav. geol. zavod, beograd, 55 p. žagar-sakač, a. (2003): hyriopsis (limnoscapha) slavonicus n. sp. (lamellibranchiata, unionidae, hyriopsinae) from miocene strata in slavonia, croatia.– nat. croat., zagreb, 2/1, 73–82. žagar-sakač, a. (2004): the ottnangian unionaceae from jelov dol.– nat. croat., 3/2, 225–252. manuscript received july, 7, 2008 revised manuscript accepted november 4, 2008 geo.cro.2-3-61-kb.pdf 159 �filippo barattolo1, bruno granier2, roberta romano3 and bruno ferré4 ab stra ct new observations on abundant material from the type locality of petrascula iberica (dragastan & trappe) granier et al. reveal the presence of a reproductive structure (ampulla) located on the inner-middle part of each primary lateral. this fact suggests a new interpretation of the alga and the establishment of a new genus: granieria barattolo & romano, n. gen. also, the taxonomic status of the other club-shaped specimens from both the high and middle atlas of morocco and the central apennines of italy is reviewed. keywor ds: club-shaped dasycladales, systematic, high and middle atlas – morocco, north-eastern spain, central apennines italy, early jurassic 1 dipartimento di scienze della terra, università degli studi di napoli, federico ii, largo san marcellino 10, i-80138 napoli, italy; (lippolo@cds.unina.it) 2 département des sciences de la terre, ufr des sciences et techniques, université de bretagne occidentale (ubo), 6, avenue le gorgeu, f-29238 brest cedex 3, france; (bgranier@univ-brest.fr) 3 dipartimento di scienze geologiche, ambientali e marine, università di trieste, via weiss 2, trieste, italy; (robroman@unina.it) 4 2 rue guy de maupassant, f-76800 saint-étienne du rouvray, france; (bruno.ferre@laposte.net) petrascula iberica (dragastan & trappe), tersella genotii barattolo & bigozzi, and the relationships of club-shaped dasycladalean algae during late triassic-early jurassic times geologia croatica 61/2–3 159–176 6 figs. 1 tab. 4 pls. zagreb 2008 geologia croaticageologia croatica � 1. introduction this paper begins with a discussion of the taxonomic history of three dasycladalean taxa: petrascula, tersella and dissocladella. it is a good example of the complexity of taxonomic work, in which the timing of the publication of a taxonomic revision and the quality of the material used to make it are of critical importance. we summarize the main steps in the last twenty years regarding changes in the attributions of these three genera. deloffre & laadila (1991) described a large clubshaped dasycladales from the lowermost jurassic strata of the middle atlas (morocco) and ascribed it to palaeodasycladus mediterraneus (pia). barattolo et al. (1994) suggested that the specimens illustrated by deloffre & laadila (1991) should be referred to the genus tersella. at the “6th international symposium on fossil algae” (6th i.s.f.a.) held in ankara (1995), granier et al. (1995) report ed that the moroccan species then consequentially designated as palaeodasycladus mediterraneus (pia) was similar to the forms that dragastan & trappe (1986) had set up as dissocladella iberica and dissocladella ebroensis. granier et al. (1995) referred the previous cited species to the genus petrascula and named it petrascula iberica (dra gastan & trappe) while discarding dissocladella ebroensis as a junior synonym. unfortunately the proceedings of the ankara meeting were never published. however these geologia croatica geologia croatica 61/2–3 160 authors were invited to submit the unpublished paper to the 7th i.s.f.a. volume (nanjing, 1999). this volume was issued four years later (granier et al., 2003) so fi nally the new designation was in print. however between the fi rst proposal (granier et al., 1995) and its valid publication (gra nier et al., 2003), a new paper (barattolo & bi goz zi, 1996) was issued concerning the taxonomic status of the iberian and moroccan specimens. in it, the authors introduced a new tax on, tersella genotii, erected to designate an early jurassic alga from central italy. barattolo e bigozzi (1996) suggested the close affi nity of this new taxon with the moroccan specimens previously attributed by deloffre & laadila (1990) to palaedasycladus mediterraneus pia. moreover, they suggest ed that all the spanish specimens described by dragastan & trappe (1986) may be but one species of tersella. the new combination tersella iberica is used in barattolo & romano (2005). more recently the comparison between sets of measurements from granier et al., (1995, 2003) and barattolo & bigozzi (1996) enabled granier et al., (2003) at the 8th i.s.fa. (granada, september 2003), to confi rm the taxonomic identity of the moroccan and iberian specimens, thus as signing them to petrascula iberica (dragastan & trappe). at about the same time, shortly before the granada sym posium, barattolo and romano collected samples from the lowermost jurassic strata of prejano (northeastern spain), the type locality of dragastan & trappe’s (1986) species. the data supplied by the new spanish material required that for its correct allocation not only the former attribution to dis socladella be discarded, but also that the subsequent assignments to both tersella and petrascula be abandoned. well then, the peculiar characteristics observed suggest that this taxon represents a new genus. these new data were presented at the “9th international symposium on fossil algae” (zagreb, september 2007). the generic identity of the other italian and moroccan specimens was confi rmed and both were referred to tersella. in the fol lowing section we report the conclusions derived from the study of moroccan (high and middle atlas) material and describe the new genus detected in the spanish deposits. 2. specimens from the high atlas, morocco in the toundout area (moroccan high atlas, see blomeier & reijmer, 1999), our colleague, a. poisson, found dasycladacean algae in lower jurassic oolitic deposits. the oolitic rocks are made of bioclastic-algal fl oatstones with radial-ooid grainstone matrices. sixty-four thin sections were prepared and analyzed using a mitutoyo measuring microscope. this study revealed that, in spite of wide variability in measurements (ranging from 25 to 59% on any one parameter), these algal remains are representatives of but one species because they are all characterised by a unique branching pattern. in this earliest jurassic species, the calcifi ed branches consist of a large club-shaped phloiophorous primary pore bearing a cluster of (probably six) secondary open pores with key-hole shaped longitudinal diameters, i.e. they are globular in their proximal part, show a narrowing in their median part, and widen at their distal end. this pattern is similar to the one known from the species tersella alpina cros & lemoine. pore lengths (l) and diameters (p) range considerably in their degree of calcifi cation. therefore the variability in the dimensions of these parameters is closely related to the variability in the thickness (e) of the calcifi ed sheet, i.e. up to about 30%. considering outer (d) and inner (d) diameters of the thallus sections, as already mentioned, variability is even greater (up to 59 per cent). the outer diameter ranges between 1262 to 8187 µm (average: 4274 µm); the inner diameter is from 749 to 7044 µm (average: 3163 µm). a cross-plot diagram of both parameters clearly displays two linear trends (fig. 1), suggesting that either there is a degree of segregation within a single species or there are two species, varieties or forms (e.g. fertile versus sterile forms). the fi rst option is preferred. 3. specimens from the middle atlas, morocco, and their generic assignment deloffre & laadila (1991) described a large clubshap ed dasycladalean alga from the lower jurassic strata of morocco. they ascribed it to palaeodasycladus mediterraneus (pia), but according to barattolo et al. (1995), the illustrated specimens did not belong to this species. additional ob servations on the branching pattern and many precise mea surements lead to the conclusion that the well-preserved specimens here and the ones from the high atlas represent the same species. the two linear trends observed on the cross-plot diagram (fig. 1) of outer (d) and inner (d) diameters are the result of the varying degrees of calcifi cation in any one specimen. the head of this club-shaped alga is relatively less calcifi ed than its stalk (outer diameter smaller than 4500 µm). pri mary and secondary branches are calcifi ed in both the stalk and the head; there is no evidence of tertiary branches. some sections show the characteristic apical opening of the clubshaped head (fig. 2). this species is therefore related to the genus tersella j. morellet in j. morellet & ters 1951. in the middle atlas, the dimensions of the specimens are even greater than those previously observed from the high atlas. here, the algae were fossilised in situ within a boundstone facies, whereas the oolitic grainstones of the high atlas are reworked debris that underwent some mechanical sorting. in conclusion the specimens from both the middle and the high atlas are referable to this single species. in addition, the general size of the biometric parameter suggests that these specimens are referable to tersella genotii. 4. specimens from the iberian range, spain and their specific assignment dragastan & trappe (1986) described a rich algal as semblage from the lowermost jurassic strata of prejano (north eastern spain) (fig. 3). these algal remains were as cribed to “dissocladella lucasi (cros & lemoine)” (originally qu oted as linoporella), “gyroporella retica (zanin buri)” (originally quoted as macroporella), sestrosphaera liasina pia, and to three new species: dissocladella ebroensis dra gast an & trappe, dissocladella iberica dragastan & geologia croaticafilippo barattolo et al.: petrascula iberica (dragastan & trappe), tersella genotii barattolo & bigozzi, and the relationships ... 161 trappe, and “macroporella nov. sp.”. as in the moroccan high atlas, this assemblage was found in grainstones of radial ooids and bioclasts often enveloped in micritized and microbialitic fi lms. new material from spain includes a considerable number of well-preserved specimens that, using the new biometric information collected, allows a complete characterization of the shape, size and general anatomy of the entire plant body. a statistical analysis of 72 specimens showed that the ratio between the outer (d) and inner (d) diameters of the specimens clearly displays a linear trend. according to gra nier et al. (1995, 2003), this linearity suggests that the dimensi on al differences between specimens can be ascribed to nor mal intraspecifi c variation. the specimens previously described as dissocladella iberica and dissocladella ebroensis are consequently only one species. new data from the re-sampled type locality, moreover, demonstrate that this species must be re ferred to a new genus for which we propose the taxonomic com bination granieria iberica. fi gu re 1: tersella genotii (lower jurassic strata, toundout, high atlas, morocco). cross-plot diagrams of the calcifi cation thickness (triangles) and of the inner diameter (y axis) versus the outer diameter (x axis). there are two discrete trend-lines: the smallest diameters (empty squares) correspond to the stalk, the largest ones (black squares) to the head. all dimensional values are provided in µm. fi gu re 2: a – thin section of the high atlas material with tersella genotii (lotharingian strata, n ribat el khaďr, middle atlas, morocco), showing some unfragmented specimens of tersella genotii. b – polished section (counterpart of the rock sample illustrated by deloffre & laadila, 1990, pl. i, fi g. 3, and from which the thin section was cut) showing several specimens of tersella genotii. arrows point to some well preserved apical apertures. geologia croatica geologia croatica 61/2–3 162 5. systematics (filippo barattolo and roberta romano) division: chlorophyta order: dasycladales pascher, 1931 family: dasycladaceae berger & kaever, 1992 tribe: bornetellae (morellet, 1913) bassoullet et al., 1979 genus: granieria barattolo & romano, n. gen. origin of the name: the genus is dedicated to our col league and friend bruno granier in observance of his great contributions to the fund of knowledge on fossil dasycladales. type species: granieria iberica (dragastan & trap pe) barattolo & romano, n. comb. diagnosis: club-shaped simple thallus, phloiophorous primary laterals arranged in more or less close whorls (eus pondyl arrangement). short phloiophorous secondary laterals making a cortex. one ampulla is attached on the side of each primary lateral in its innermiddle part (reproduction of choristosporous type). comparisons: at fi rst sight the new genus closely resembles other club-shaped early jurassic genera like tersella and petrascula, and less so palaeodasycladus and sestrosphaera. nevertheless granieria differs from all these genera mainly in the apparatus of reproduction (choristosporous) rather than cladosporous or endosporous and in part in the number and shape of the laterals. with regard to verticils, granieria differs from palaeodasycladus and petrascula in the orders of ramifi cation, (three in petrascula and palaeodasycladus rather than the two of granieria). moreover in petrascula the tertiary laterals do not make a cortex. choristosporous rather than cladosporous reproduction is obviously the main criterion distinguishing granieria from tersella. the more or less differentiated club-shaped thallus, the presence of the terminal opening related to the same type of apical zone, the two order ramifi cation and the general setting of the calcareous skeleton, are all characteristics shared by granieria and tersella. consequently the occurrence of the lateral ampulla on the primary lateral represents the sole diagnostic character that distinguishes the new genus from tersella. taking into account the importance of reproductive structures in taxonomy (e.g. berger & kaever, 1992), this fact suggests a separation of the two genera at the family level. in any case, the main problem in the taxonomy of fossil dasycladaleans is their degree of calcifi cation. the amount of calcifi cation is extremely variable (extensive, scattered or absent). consequently, the structure of the alga must be interfi gu re 3: a – location of the type-locality of granieria iberica nov. comb. b – field photography of the prejano outcrop. the studied sample was collected from the oolithic massive level (arrow), field of view is approximately 0.5 km wide. c – schematic diagram of lower jurassic deposits of the prejano area, with the position of the dasycladales bearing level (modifi ed from dragastan & trappe, 1986). geologia croaticafilippo barattolo et al.: petrascula iberica (dragastan & trappe), tersella genotii barattolo & bigozzi, and the relationships ... 163 preted only from the pores defi ned in the calcifi ed portions. the species of tersella show incomplete calcifi cation of the inner portion of the primary laterals, in particular in the upper portion of the thallus. this incomplete calcifi cation can ob scure the presence of reproductive structures on the lower portion of the primary laterals. however, the great number of specimens of tersella studied, although they differ in size, degree of calcifi cation and stage of development, confi rms the absence of a reproductive structure (ampulla) in the genus tersella. apart from its type of reproduction, the genus sestrophaera differs from granieria in: 1) the presence of only one order of laterals, 2) a more differentiated club-shaped thallus, 3) a closed, well-calcifi ed apical zone rather than an open one. granieria’s choristosporous reproduction distinguishes this new genus from that of several other genera that appeared after the jurassic (e. g. goniolina and eodasycladus). in addition, granieria differs from eodasycladus in ramifi cation order, (two lateral orders rather than three) and in the general shape of the thallus (club-shaped in granieria, cylindrical in eodasycladus). another important difference between these genera concerns the location of the ampulla. in eodasycladus the ampulla is at the outer end of the primary laterals, in granieria it is positioned on one side of them. according to berger & kaever (1992), the position of the reproductive organs with respect to the laterals is a distinctive feature, very important in the discrimination of the tribes of any one dasycladalean family. so, position of the ampulla structure on the side of the primary laterals distinguishes granieria n. gen. from eodasycladus. the placement of the ampulla on the side of the primary laterals also distinguishes granieria from the cretaceous-tertiary genera neomeris and afghanopolia, for they too are characterized by a terminal position of the ampulla on the primary laterals. granieria (one ampulla per lateral) is distinguishable from other choristosporous genera including bornetella, jodotella, goniolina and microsporangiella that have more than one ampulla per lateral. the comparison of granieria with cylindroporella, chinianella, and otternstella is complicated by the taxonomic status of these taxa that in some cases demand a careful restudy of the type species. in any event, at the present state of knowledge, otternstella and chinianella are characterized by whorls of fertile ampulla directly connected with the central stem that alternate with whorls of sterile laterals, while granieria does not have this organization into alternating verticils. cylindroporella is characterized by an alternation in the same whorl of sterile laterals and ampulla, directly connected to the central stem. in this respect too, granieria shows no alternation between sterile and fertile laterals, nor are some ampulla set directly on the main axis. otherwise, bakalovaella established by bucur (1993) shows an ampulla aside the primary laterals, but differs from granieria in the general shape of the thallus, (cylindrical versus club-shaped), and the order of ramifi cation (only one versus two). granieria shows some morphological affi nity with pseudoactinoporella conrad, emend. conrad & peybernes. according to bucur (2000) this latter genus is characterized by a club shaped thallus, but calcifi ed only in its basal part. the structure of laterals is interpreted as a short primary lateral prolonging into a single secondary lateral and giving rise to a terminal ampulla set aside. therefore the genus granieria differs from pseudoactinoporella at least for the structure of the laterals and position of the reproductive organs. actually the ampulla of granieria is attached to the inner part of a long primary lateral instead of terminally on a short one, and the secondary laterals are in tufts versus a single lateral. attribution of granieria to family and tribe: according to the berger & kaever (1992) classifi cation of the modern dasycladalean algae, an euspondyl arrangement of laterals with choristosporous gametangia attached to the mid dle part of the laterals by a short stalk restricts the attribution of granieria n. gen. to the family dasycladaceae. the presence of an individual reproductive organ (ampulla) set on the side of the primary laterals, the presence of an external cortex, and the club-shaped thallus assign granieria n. gen. to the tribe bornetellae. granieria iberica (dragastan & trappe) barattolo & romano, n. comb. (pls. i–iv) synonymy lists – only illustrated specimens: 1986 dissocladella iberica nov.sp. – dragastan & trappe, p. 174, fi gs. 3/5, 4/1–4, 5/2 1986 dissocladella ebroensis nov.sp. – dragastan & trappe, p. 176, fi g. 4/6–7 1986 dissocladella lucasi (cros & lemoine) – dragastan & trappe, p. 172, fi g. 3/1–4 1986 gyroporella retica (zanin buri) – dragastan & trappe, p. 178, fi g. 5/1 1986 sestrosphaera liasina pia – dragastan & trappe, p. 176, fi g. 4/5 1986 macroporella nov. sp. aff. sturi bystricky – dragastan & trappe, p. 178, fi g. 5/6 emended diagnosis: club-shaped simple thallus, slightly differentiated into a sub-cylindrical lower part (stalk) and an enlarged ellipsoidal upper one (head). primary laterals arranged in close alternating whorls. they are set almost perpendicularly to the main axis near the base of the thallus; as they approach the top of the thallus, the primary laterals incline upward more and more so they are set vertically near the apex. primary laterals in the stalk region have a circular cross-sec tion, are moderately long and widen outwards, in the upper part of the thallus, only the distal end of the primary laterals is preserved. secondary laterals, 3–4 per tuft, are shorter and also widen outwards. they show the same changes in inclination as the primary laterals and form a distal cortex probably with a hexagonal mesh. choristosporous reproductive organs are sited on the primary laterals. each consists of a sub-spherical ampulla connected by an inclined short peduncle to the upper side of the inner-middle portion of the primary lateral. the calcareous skeleton is thicker along the stalk where it almost entirely encases the primary laterals, the reproductive geologia croatica geologia croatica 61/2–3 164 plate i granieria iberica nov. comb. prejano (type-locality) lower jurassic (hettangian–sinemurian) 1–9 transverse-oblique sections of the lower part of the calcareous skeleton fig. 1, ba.3139.31; fig. 2, ba.3139.40; fig. 3, ba.3139.38; fig. 4, ba.3139.24; fig. 5, ba.3139.37; fig. 6, ba. 3139.29; fig. 7, ba.3139.16; fig. 8, ba.3139.39; fig. 9, ba.3139.1. 10–12 oblique sections of the lower part of the calcareous skeleton. fig. 10, ba.3139.25; fig. 11, ba.3139.28; fig. 12, ba. 3139.26. geologia croaticafilippo barattolo et al.: petrascula iberica (dragastan & trappe), tersella genotii barattolo & bigozzi, and the relationships ... 165 geologia croatica geologia croatica 61/2–3 166 plate ii granieria iberica nov. comb. prejano (type-locality) lower jurassic (hettangian – sinemurian) 1–4 oblique sections of the lower part of the calcareous skeleton. fig. 1, ba.3139.40; fig. 2, ba.3139.14; fig. 3, ba.3139.34; fig. 4, ba. 3139.22. 5–6 longitudinal sections. fig. 5, ba. 3139.22; fig. 6, ba. 3139.29. geologia croaticafilippo barattolo et al.: petrascula iberica (dragastan & trappe), tersella genotii barattolo & bigozzi, and the relationships ... 167 geologia croatica geologia croatica 61/2–3 168 plate iii granieria iberica nov. comb. prejano (type-locality) lower jurassic (hettangian – sinemurian) 1–2 oblique sections of the stalk and its junction with the head. fig. 1, ba.3139.29; fig. 2, ba.3139.42. 3 oblique section of the upper part of the calcareous skeleton, ba.3139.40. 4 detail of the fig. 2. note the double pores vertically paired. these represent the primary laterals and the ampulla cut in their proximal part; ba. 3139.242. 5–7 detail of the ampulla setting in the upper inner portion of the primary laterals. fig. 5, ba. 3139.8; fig. 6, ba. 3139.43; fig. 7, ba.3139.8. geologia croaticafilippo barattolo et al.: petrascula iberica (dragastan & trappe), tersella genotii barattolo & bigozzi, and the relationships ... 169 geologia croatica geologia croatica 61/2–3 170 plate iv granieria iberica nov. comb. prejano (type-locality) lower jurassic (hettangian – sinemurian) 1–2 oblique sections showing the gentle transition between the lower and upper portion of the calcareous skeleton. fig. 1, ba.3139.18; fig. 2, ba.3139.27. 3 oblique section, ba.3139.22. 4 oblique section of the upper enlarged portion of the calcareous skeleton, ba. 3139.20. geologia croaticafilippo barattolo et al.: petrascula iberica (dragastan & trappe), tersella genotii barattolo & bigozzi, and the relationships ... 171 geologia croatica geologia croatica 61/2–3 172 organs and the initial portion of the secondary laterals; elsewhere the calcifi cation is thinner; in the upper part of the skeleton it envelops only the distal end of the primary laterals and the inner-middle portion of the secondaries. close to the apex the calcareous skeleton is a little thicker, but probably does not affect the apex leaving an opening. the most signifi cant biometric values are listed in table 1. general features of the calcareous skeleton: the calcareous skeleton is simple, continuous, without annulation or in tu sannulation. it exhibits moderate differentiation into a sub-cylindrical lower part (stalk) and a gradually enlarged upper part (head). the term “stalk” and “head” is used in the description although the transition between these two elements is ge nerally not sharp or well defi ned (pl. iii, fig. 1; pl. iv, fig. 2). table 1: the most signifi cant biometric values of granieria iberica nov. comb from sample ba.3020 are supplied. all dimensional values are in millimetres. d = outer diameter of the stalk, d = inner diameter of the stalk, e = calcifi cation thickness, pi = width inner of the primary, pd = outer width of the primary lateral, l = length of the primary lateral, p’ = width of the secondary lateral, l’ = length of the secondary lateral, h = height between whorls, w = number of primaries in a whorl. granieria iberica nov. comb. sample specimen section d d e pi pd l p’’ l’ h w ba 3139 1 3139..41 2,70 1,35 0,68 0,04 0,18 0,55 0,36 ba 3139 2 3139..41 5,00 4,30 0,35 0,20 0,10 0,15 ba 3139 3 3139..41 2,75 1,82 0,47 0,07 0,15 0,40 0,33 ba 3139 4 3139..41 2,85 2,15 0,35 0,06 0,13 ba 3139 5 3139..38 1,70 1,10 0,30 0,07 0,10 0,10 0,10 ba 3139 6 3139..38 2,20 1,25 0,48 0,07 0,15 0,30 0,08 0,09 0,32 ba 3139 7 3139..38 2,20 1,15 0,53 0,06 0,15 0,55 24 ba 3139 8 3139..38 1,90 1,10 0,40 ba 3139 9 3139..26 2,40 1,50 0,45 0,06 0,16 0,45 0,10 0,10 0,22 31 ba 3139 10 3139..26 2,35 1,50 0,43 ba 3139 11 3139..26 2,10 1,50 0,30 0,08 0,16 0,30 ba 3139 12 3139..26 2,60 1,65 0,48 0,18 0,25 0,12 28 ba 3139 13 3139..15 2,90 2,30 0,30 0,06 0,15 0,10 36 ba 3139 14 3139..42 1,50 0,80 0,35 0,28 ba 3139 15 3139..42 2,54 1,90 0,32 ba 3139 16 3139..37 2,22 1,35 0,44 0,05 0,11 0,35 0,10 0,10 24 ba 3139 17 3139..37 2,00 1,40 0,30 ba 3139 18 3139..39 2,80 1,70 0,55 0,08 0,11 0,50 0,10 30 ba 3139 19 3139..39 2,10 1,05 0,53 0,07 0,15 0,40 0,12 0,27 ba 3139 20 3139..40 2,10 1,15 0,48 0,08 0,16 0,40 0,10 0,07 22 ba 3139 21 3139..40 3,00 1,80 0,60 ba 3139 22 3139..40 2,30 1,20 0,55 0,10 0,19 0,45 0,08 0,01 0,35 ba 3139 23 3139..40 4,80 3,80 0,50 0,01 0,21 0,60 0,35 ba 3139 24 3139..40 1,70 1,00 0,35 0,08 0,11 0,25 0,10 0,10 20 ba 3139 25 3139..40 2,10 1,15 0,48 0,08 0,13 0,47 0,25 ba 3139 26 3139..40 1,80 1,20 0,30 0,08 0,18 0,28 20 ba 3139 27 3139..28 2,60 1,80 0,40 0,08 0,15 0,30 0,10 0,10 0,23 ba 3139 28 3139..28 1,80 1,00 0,40 0,10 0,12 0,50 22 ba 3139 29 3139..34 2,00 1,00 0,50 0,08 0,20 0,35 0,25 ba 3139 30 3139..34 1,70 1,00 0,35 0,10 0,12 20 ba 3139 31 3139..34 2,00 1,20 0,40 0,60 ba 3139 32 3139..35 2,90 1,55 0,68 0,10 0,15 0,40 0,10 0,10 24 ba 3139 33 3139..31 2,10 1,30 0,40 0,08 0,15 0,40 0,30 ba 3139 34 3139..31 2,05 0,90 0,58 0,07 0,13 0,40 0,10 0,10 ba 3139 35 3139..31 1,90 1,10 0,40 0,10 0,15 0,30 ba 3139 36 3139..31 2,00 1,30 0,35 ba 3139 37 3139..36 2,40 1,50 0,45 0,08 0,15 0,45 30 ba 3139 38 3139..43 1,60 0,90 0,35 ba 3139 39 3139..43 1,90 1,10 0,40 ba 3139 40 3139..43 2,40 1,60 0,40 0,07 0,15 0,40 0,30 geologia croaticafilippo barattolo et al.: petrascula iberica (dragastan & trappe), tersella genotii barattolo & bigozzi, and the relationships ... 173 the stalk is cylindrical, fl aring slightly upward. it is rather strongly calcifi ed, for generally the entire length of the primary laterals is encased, or at least most of it, and occasionally the sheath extend outward to include the inner portion of the secondary laterals (pl. i, figs.1–6; pl. ii, fig. 2). calcifi cation does not usually attain the central stem because the inner surface of the calcareous skeleton is often irregular and the tapering proximal part of the primary laterals close to their junctions to the main axis is rarely observable. the head is ellipsoidal to ovoid, somewhat elongate; cal cifi cation is rather thin there, but it envelops the distal end of the primary laterals and a part of the secondaries (see forward, fig. 4). near the top, the amount of calcifi cation increases so thinner primary and secondary laterals are encased, but it does not seem to be present at the apex, leaving an opening as in some species of the genus tersella (fig. 4b–c). in any case, the rare sections of the entire head never show this opening probably because they do not precisely cut the axis of the apic al zone. the inner diameter starts at 0.70 mm in the stalk and reaches 4.3 mm in the head portion. in the same way the outer diameter ranges from 1.40 mm in the stalk to 5.0 mm in the head. granieria iberica nov. comb. sample specimen section d d e pi pd l p’’ l’ h w ba 3139 41 3139..43 2,50 1,50 0,50 0,07 0,20 0,45 0,30 ba 3139 42 3139..7 4,00 3,00 0,50 0,10 0,20 0,48 0,35 ba 3139 43 3139..7 3,35 2,00 0,68 0,08 0,20 0,40 0,10 0,10 0,35 ba 3139 44 3139..7 4,20 3,25 0,48 ba 3139 45 3139..7 1,90 0,90 0,50 ba 3139 46 3139..24 2,20 1,30 0,45 0,08 0,17 0,40 0,10 0,06 26 ba 3139 47 3139..24 3,70 3,00 0,35 ba 3139 48 3139..24 1,85 0,78 0,54 0,06 0,15 0,40 0,10 0,10 ba 3139 49 3139..24 2,20 1,60 0,30 0,30 0,25 ba 3139 50 3139..24 2,20 1,40 0,40 ba 3139 51 3139..29 2,50 1,50 0,50 0,07 0,18 0,48 ba 3139 52 3139..29 1,90 1,05 0,43 0,05 0,13 0,45 ba 3139 53 3139..29 4,50 3,70 0,40 0,22 ba 3139 54 3139..29 2,20 1,60 0,30 ba 3139 55 3139..29 3,45 2,20 0,63 0,08 0,20 0,45 0,13 0,15 ba 3139 56 3139..32 3,50 2,60 0,45 ba 3139 57 3139..30 2,45 1,50 0,48 0,10 0,15 0,45 0,30 ba 3139 58 3139..30 2,15 1,20 0,48 0,07 0,14 0,40 0,27 ba 3139 59 3139..30 3,40 2,80 0,30 ba 3139 60 3139..25 2,40 1,55 0,43 0,08 0,12 0,30 0,25 ba 3139 61 3139..25 3,50 2,95 0,28 ba 3139 62 3139..25 3,10 2,00 0,55 0,06 0,20 0,50 0,30 ba 3139 63 3139..22 2,40 1,35 0,53 0,07 0,15 0,40 0,28 ba 3139 64 3139..22 2,10 1,10 0,50 0,01 0,20 0,45 0,10 0,06 0,35 ba 3139 65 3139..11 2,10 1,20 0,45 0,07 0,15 0,40 0,35 ba 3139 66 3139..11 2,20 1,25 0,48 0,07 0,20 0,47 0,32 ba 3139 67 3139..11 1,40 0,70 0,35 ba 3139 68 3139..14 2,90 1,80 0,55 0,08 0,17 0,45 0,08 0,12 0,27 ba 3139 69 3139..14 2,30 1,60 0,35 0,07 0,20 0,35 ba 3139 70 3139..14 2,50 1,50 0,50 0,07 0,18 0,48 0,30 ba 3139 71 3139..14 2,60 1,60 0,50 0,08 0,20 0,45 28 ba 3139 72 3139..12 2,00 1,10 0,45 0,05 0,15 0,50 0,30 ba 3139 73 3139..12 2,25 1,70 0,28 74 number 73 73 73 49 51 46 18 20 31 15 min 1,40 0,70 0,28 0,01 0,10 0,25 0,08 0,01 0,22 20,00 max 5,00 4,30 0,68 0,10 0,21 0,60 0,13 0,15 0,36 36,00 average 2,491 1,612 0,439 0,072 0,160 0,422 0,098 0,098 0,295 25,667 st. devation 0,743 0,732 0,098 0,019 0,030 0,081 0,031 4,746 table 1: continued geologia croatica geologia croatica 61/2–3 174 primary laterals: the primary laterals are set perpendicularly to the main axis along the greater extent of the thallus (pl. ii, figs. 4–6; pl. iii, fig. 3), but moving up to the apical zone the inclination of the laterals increases until they probably stand roughly vertically at the apex. the primary laterals in the lower part of the stalk are phloiophorous, club-shaped, their diameter gradually increasing in size outwards (pl. ii, figs. 4–5). moving from the stalk to the head, the primary laterals tend to assume a slight differentiation into a inner sub-cylindrical portion and a more globular distal portion (pl. iv, figs. 1–2). the laterals are circular if cross sectioned and their diameter ranges from 0.01–0.10 (pi) to 0.10–0.15(pd) mm, in the inner and the distal parts respectively. the junction between primary laterals and the central stem is never observed because the calcifi cation does not reach the main axis. the primary laterals of the head are apparently short, bigger than those of the stalk (0.15–0.21 mm), and globular in shape (pl. iv, fig. 1). their reduced length is combined with a large central cavity; this fact seemingly is the result of calcifi cation restricted to the distal part of the primary laterals. this assumption is strengthened by the trend of calcifi cation which tapers upward in the stalk/head transition and because the primary pores open to the inner cavity through large pores. the primary laterals are arranged in simple euspondyl whorls. the number of primary laterals for each whorl is 20–24 mm in the stalk and reaches 40–46 mm in the head. subsequent whorls exhibit laterals arranged in alternate position (pl. ii, figs. 1, 4). the height between whorls (h) is 0.22–0.36 mm. secondary laterals: the secondary laterals originate from the distal part of the primary laterals. the secondary laterals are mainly observable in the middle and upper parts of the thallus, while in the lower stalked part they are rarely visible, because they are only rarely encrusted by calcifi cation. anyway their size and number per tuft (3–4) remain constant throughout the whole thallus. secondary laterals are rather short and quickly fl are out wards (pl. i, figs. 7–8, 12). they display a close packed ar rangement at the outer surface of the calcareous skeleton (pl. iv, fig. 3). this fact allows for the argument that the uncalcifi ed distal parts were adequately widened out in order to touch laterally in order to form a cortex. reproductive organs: a single sub-spherical ampulla per primary lateral (0.10–0.18 mm,) is attached, through an inclined short peduncle, on the upper side, in the inner-middle portion of the lateral. only a few well preserved longitudinal sections of the stalk (pl. iii, figs. 5–7) clearly show this characteristic. however the presence of such structures can be detected more frequently in tangential and oblique sections cut very close to the central cavity. the whorl appears to be constituted by a row of vertically paired pores (pl. iii, figs.1– 2, 4). the pores of a couple are set very close to each other and are of comparable size. on moving laterally the paired pores disappear and only a row of single pores, increasing in size, continues. each couple of pores represents the section of the inner portion of the primary lateral and the ampulla or its oblique peduncle. reproductive organs are only preserved in the stalk be cause the calcifi cation almost completely encrusts the primary laterals. the fact that calcifi cation in the head is restricted to the distal part of the primary laterals means that all the inner structures are not preserved. reconstruction: most elements of the thallus that are calcifi ed have been described above. only the shape of primary laterals in the upper part of the thallus, the presence of the reproductive structure in the head and the outer end of the secondary laterals are not preserved and are therefore treated here in a prospective reconstruction of the thallus (figs. 5–6). fi gu re 4: close up of the three diff erent apical zones showing that the calcifi cation thickness increases enveloping thinner primary and secondary laterals, but seemingly, it disappears at the apex, leaving a cavity. a – granieria iberica nov. comb. b – tersella alpina (close-up from cros & lemoine, 1967). c – tersella genotii (close-up from barattolo & bigozzi, 1996). geologia croaticafilippo barattolo et al.: petrascula iberica (dragastan & trappe), tersella genotii barattolo & bigozzi, and the relationships ... 175 the uncalcifi ed primary laterals in the upper part of the thallus are assumed to be similar to those in the lower part, but are comparatively longer. the reproductive structures are thought to be present in the head too because in other dasycladales it is specifi cally the upper part of the thallus that is deputed to reproduction. the position of the ampulla has been postulated as similar to that of those visible in the lower part of the thallus, but larger in comparison to the size of the lateral. finally the top of the thallus is believed to resemble those of other morphologically similar fossil genera such as tersella (e.g. tersella alpina, tersella genotii). comparisons: as discussed above, granieria displays close analogies with other club-shaped early jurassic genera. in particular the type species granieria iberica (dragastan & trappe) nov. comb. shows a marked resemblance to the genus tersella. granted that the presence of a choristosporous type of reproductive apparatus (ampulla) is suffi ciently decisive to distinguish granieria iberica n. comb from all not-choristosporous species of tersella, there are other morphological differences. tersella genotii barattolo & bigozzi and tersella incompleta morellet are very close to granieria iberica in that they share a slightly differentiated club shaped calcareous skeleton and a general similarity in the pattern of calcifi cation from the stalk to the head. t. genotii is larger than granieria iberica and its secondary laterals are cylindrical to slightly wid ened outwards rather than short and cone shaped as in granieria iberica. t. alpina cros & lemoine shows a narrowing in the middle portion of the secondary laterals, and t. incompleta also narrows, but in the sub-terminal portion, while granieria iberica has regularly widening short, cone-shaped, secondary laterals. finally, tersella quercensis differs from granieria iberica in that a distinction between head and thallus is well-marked in the club-shaped skeleton. granieria iberica shares its choristosporous type of reproduction with cylindroporella?liasica but the thallus in this species is cylindrical, not a moderately differentiated clubshape. the fertile ampulla is larger and forms an elongated ellipsoid rather than sub-spherical globe (granieria iberica). fi gu re 5: granieria iberica nov. comb. reconstruction of the thallus in longitudinal view. left side: stem, primary laterals and calcifi cation (black) in axial section. right side: longitudinal view of the thallus without calcifi cation; in the lower part a perspective view of the primary and secondary laterals, and cortex is drawn. fi gu re 6: granieria iberica nov. comb. reconstructions in transverse view. left-side transverse section at whorl level showing primary and secondary laterals and calcifi cation (black); right-side: primary, secondary laterals and ampulla without calcifi cation. lower – stalk region, upper – head region geologia croatica geologia croatica 61/2–3 176 6. conclusions the taxonomic relationships of several forms of dasycladales from morocco, italy and spain are more complicated than previously supposed. the validity of tersella genotii from central italy (gran sasso, barattolo & bigozzi, 1996) is confi rmed. the moroccan specimens initially described as palaeodasycladus mediterraneus by deloffre & laadila (1991) are now referred to tersella genotii. this attribution is based on the restudy of two discrete moroccan dasycladalean assemblages, one from the high atlas and the other from the middle atlas. the spanish specimens formerly described as dissocladella ebroensis and d. iberica, dissocladella lucasi (cros & lemoine), gyroporella retica (zanin buri), sestrosphaera liasina pia and “macroporella nov. sp.” by dra gast an & trappe (1986), are referred to a single species in agreement with the work of granier et al. (1995, 2003) and barattolo & bigozzi (1996), but here this species is referred to the new genus granieria. the establishment of the new genus granieria brings to light that in the early jurassic the genera developed, although apparently similar in aspect, are fundamentally different in reproductive strategy. the position of cylindroporella? liasica (barattolo & parente 2000) should be analyzed in the light of the coincident occurrence of a structurally similar taxon, granieria, which differs mainly in the shape of the thallus. acknowledgment the present research has been funded by a grant from murst (prin 2004 barattolo). many thanks are due to nestor j. sand er for improving the manuscript by means of constructive and appropriate remarks. sincere thanks to i. bucur and f. schagintweit for their suggestions and comments. references barattolo, f., de castro, p. &. parente, m. (1995): some remarks on the genera palaeodasycladus (pia, 1920) pia, 1927 and eodasycladus cros & lemoine, 1966 ex granier, b. & deloffre, r. (1993) (green algae, dasycladales). – in: piller, w.e. (ed.): proceedings of the international symposium and field-meeting “alpine algae ‘93”. beiträge zur paläontologie, 19 (1994), 1–11. barattolo, f. & bigozzi, a. (1996): dasycladaleans and depositional environments of the upper triassic–liassic carbonate platform of the gran sasso (cental appennines, italy). – facies, 35, 39–54. barattolo, f. & parente, m. (2000): new observation on uragiella liasica (lebouché & lemoine) (green algae, dasycladales) from the type-locality (canders, languedoc-southern france). – boll. soc. paleont. ital., 39/2, 123–137. barattolo, f. & romano, r. (2005): some bioevents at the triassic–liassic boundary in the shallow water environment. – boll. soc. geol. ital., 124, 123–142. bassoullet, j.-p., bernier, p., deloffre, r., genot, p., jaffrezo, m., & vachard, d. (1979): essai de classifi cation des dasycladales en tribus. – in: 2eme symposium international sur les algues fossiles (paris, 23–26 avril 1979). bull. centr. rech. explor. – prod. elf-aquitaine, 3–2, 429–442. berger, s. & kaever, m.j. (1992): dasycladales. an illustrated monograph of a fascinating algal order. – georg thieme verlag, stuttgart, 247 p. blomeier, d.p.g. & reijmer, j.j.g. (1999): drowning of a lower jurassic carbonate platform: jbel bou dahar, high atlas, morroco. – facies, 41, 81–110. bucur, i.i. (1993): some new or poorly known calcareous algae (dasycladales, gymnocodiacea) in the lower cre taceous deposits from the resita – moldova noua zone (southern carpathians, romania). – rev. espan. micro pal., 25/1, 93–126. bucur, i.i. (2000): lower cretaceous dasyclad algae from the from padurea craiului massif (northern apuseni mountains, romania). – acta palaeont. roman., 2, 53–72. cros, p. & lemoine, m. (1967): dasycladacées nouvelles ou peu connues du lias inférieur des dolomites et de quelques autres régions méditerranéennes (2e partie). – rev. micropal., 9/4, 246–257. deloffre, r. & laadila, m. (1990): un niveau exceptionnel à palaeodasycladus mediterraneus dans le lotharingien du moyenatlas (maroc) – emendation du genre et de l’espèce-type. – rev. paléobiol., 9/2, 309–320. dragastan, o. & trappe, j. (1986): some dasyclad algae of the sinemurian from the north-western iberian chains (spain). – paläont. zeitschr., 60/3–4, 169–179. granier, b., poisson, a., ferré, b. & deloffre, r. (1995): new data on a liassic club-shaped dasycladacean. – in: güvenç, t. (ed.): 6th international symposium on fossil algae and carbonate platforms, ankara (september 18th–22nd), abstracts, 1 p. granier b., poisson, a., ferré, b. & deloffre, r. (2003): new data on petrascula iberica dragastan et trappe 1986, n. comb., a liassic club-shaped dasycladacean. preliminary note. – acta micropal. sinica, 20/1, 67–74. morellet, j. & ters, m. (1951): deux dasycladacées du lias de vendée.boll. soc. géol. france, (6), i, 643–648. pascher, a. (1931): systematische übersicht über die mit flagellaten in zusammenhang stehenden algenreihen und versuch einer einreihung dieser algenstämme in die stämme des pfl anzenreiches. botanisches centralblatt, 48, 317–332. manuscript received may 19, 2008 revised manuscript accepted june 16, 2008 ge ol. c roat. 49/2 34 1 zag reb 1996 ah..,fracf nore applications of the petrophysical properties of oil and gas reservoirs for exploration and development geology in albania dasham ir mezini and gene melonashi thorough comprehension of the way in which capi l­ lary pressure in a reservoi r affects hydrocarbon mi gra­ tion and entrapment is invaluable , if one is to learn and apply ne w me thodology in the search for hydrocarbon poo ls. t he method or capilla ry pressure has prio rit y in solvi ng some of the practical proble ms of exploration and development geology. this study present s the seg­ ment of capillary propert ies of oil and gas reservoirs as only one aspec t o f several yea rs' research of mo rc soph is ti cated and app licable me thods in petrophysics. a to tal of approxim ate ly 200 analyses of sandstone cores from the albanian oil and gas fie lds were under­ taken during this study. t he f inal objecti ve of the study was three fold: to upho ld th e pct rop hysica l know ledge o f th e a lbanian sandstonc hydrocarbon reservoirs that was obtained bascd on rout ine paramcters; to resolve some debatab le prob lems of the domestic ex ploration and de ve lopm e nt geo logy of o il and gas; to mode l the sys te m "sea l reservoir oi l and gas satu ration " based on the pctrophys ica l prope rt ics. in re lation to the firs t aspect, a comparison has bcen made be tween capi llary parameters and rou tine paramc­ ters whi ch upholds previous conclusions: a) the vertical zonat ion o f the ph ys ica l prope rties o f the reservo ir ex is ts in the pat os marinza mono­ c lin e, as well as in the kw;ova sy ncl ine w ith the tre nd of properti es improving from the bottom of the reservoir upwards; b) the ven ical and late ra l heterogeneity of the distribu­ tion o f the pe trophysical prope rt ies both w ithin a bed a nd from the reservoir bed decreases from the bot tom of the reservoir upwards; c) the reservoi r propert ies are reduced in the vic inity of the pi nch-ou ts; oit and gas institu te, pctrophysical departmcllt, fief, albania. d ) sati s fac tory correla tio n exist s between th e kobe poros it y and irreducible wate r saturat ion. as faf as the second aspect is concerned , ane mpts have bee n made to reso lve the [a ll o wing proble ms usin g th e ca pil lary concepts combi ned wi th rese rvo ir geometry and struct ural , sedime nt o log ical and pe tro­ physical parameters: the problem of alte rnating gas-saturated and wate r­ sa turated beds in messinian and to rtonian de pos its (frahl l i-divjaka-ball aj); existence of ei ther the sharp hydroca rbon-water con­ tact or ihe transilional zone; the hete rogeneous d is tr ibution of oi l and gas satura­ ti on with in a reservoi r, toge the r w ith the poss ible formation of a pe rmeabil ity barri e r within a reser­ voir; the reservo ir-seal re lat ionship and ex pla natio n of filled and barren traps. concerning the third aspect, an orig ina l solution for the mode lli ng of "sea l reservo ir oi l a nd gas satura­ tion" sys tem is reached. the mode ll ing cons ide red the nature o f the reservoi rs, the ir geome tric and hyd rocar­ bon sa turation fea tu res in combination with the pe tro­ phy sica l fac tors. ni nc poss ible reservo ir types werc determined , throw ing some light on the explanati on or the irregular di str ibutio n of thc gas reservoi rs in the p liocene and tortonian sediments. the aforcmc ntioned could be of practical inte res t, especia ll y when compared to the dry well analysis in attempts to predict ri sk. the technique of capillary pressure has g reat poten­ tia l for reso lving proble ms in pe tro le um exp lorat io n, a nd explo ration geolog is ts a fe e nco uraged to make themse lves fami li a r w ith this me thod , for it is the authors' be lief tha i it w ill make them illore successful in discovering oi l and gas acculllu lations. 342 gcoiogi:1 cronlic;l49/2 1. introduction the gusiê polje compensation basin is part of the hydroenergetic system hp senj and is used for daily levelling of natural inflows of the lika and gacka rivers. although the basin is constructed in part of the polje where ponors and suffosions have not been found, after the test filling in 1965 the water losses were up to 6.4 m3/s (e l e k t r o p r o j e k t, 19654, 19665). therefore additional embankments were constructed inside the basin and the remediation of basin with a clay carpet was undertaken. however, ponors have still been opening and closing during repair of the plant, and water reservoir within the karst field overburden: gusiê polje, croatia ante pavi»i∆1, davor benamati∆ 2, damir pe©t2 and marijan marasovi∆3 water losses are between 0.5 and 1.0 m3/s, depending on the remediation level (e l e k t r o p r o j e k t, 19836; pavi»i∆, 1986). the compensation basin (fig. 1) was constructed on the basis of prediction of the satisfactory water holding capacity of the quaternary cover. karstic limestone bedrock was not taken in consideration. it was left to the test filling to determine the water-retention of the quaternary deposits, which was only done immediately before inauguration of the senj power plant. the causes of detected water losses (6.4 m3/s) were not found. for new losses, the technical solutions for remediation of places of water loss were determined. first of these appearances was the ponor in the bottom of the basin, with diameter of 2 m and depth of over 3 m. the following appearances had diameters up to 5 m and depth up to 6 m. several causes for water loss were supposed poor construction or non existence of clay carpet in the zone of the canal, as well as the existence of ponors underneath the quaternary deposits. also, occasional moisturizing of quaternary deposits through carbonate bedrock is unfavourable for the stability of quaternary deposits. for the design of optimal remediation, which should be realized as soon as possible, geophysical investigations were performed (benamati∆ et al., 19977; pe©t, 19998). these investigations consisted of geoelectrical profiling and resistivity sounding. the aim of the investigation was to determine the thickness and lithological composition of the cover deposits and karstification of the carbonate bedrock. to determine the dominant directions of groundwater seepage and zones of water sinking from the basin, the self potential meageologia croatica 55/1 93 100 8 figs. zagreb 2002 key words: surface water reservoir, karst, water losses, geophysical investigation, gusiê polje, croatia. 1 institute of geology, sachsova 2, hr-10000 zagreb, croatia; e-mail: pavicic@igi.hr 2 moho, sv. mateja 33, hr-10000 zagreb, croatia. 3 elektroprojekt, aleksandera von humboldta 4, hr-10000 zagreb, croatia. abstract the gusiê reservoir is a compensation basin constructed in the karst field. the reservoir lies on a quaternary overburden free of ponors (sinkholes) and suffosions. after the reservoir filling the water losses were up to <6.4 m3/s. the bottom impermeability has been ensured with a 0.4 m thick clay base blanket. during reservoir exploitation, suffosions and ponors developed through which 2 m3/s water was lost. such conditions required reservoir repair within a short time frame of approximately 10 days during which the power plant was shut down. when the reservoir was emptied, a resistivity sounding (wenner electrodes arrangement at five depth levels) was conducted on the reservoir bottom and clay blanket. an alternative concept has also been considered the construction of a new reservoir area that has similar hydrogeological conditions. the solution for the possible impact of groundwater (air) “pressure” could be the construction of a horizontal “vent” in the deepest part of the palaeodepression, where the bedrock karstification is the most intensive and the interrelation between groundwater and air pressure on the overburden is possible. the reservoir bottom impermeability could be resolved with a clay blanket or with synthetic materials. 4 elektroprojekt (1965): pojave ustanovljene kod pokusnog punjenja bazena gusiê polje.unpubl. report, archive of elektroprojekt, zagreb. 5 elektroprojekt (1966): mjerenje procjednih gubitaka u gusiê polju.unpubl. report, archive of elektroprojekt, zagreb. 6 elektroprojekt (1983): sanacija kompenzacijskog bazena gusiê polje hidrogeoloπki radovi.unpubl. report, archive of inst. of geology, 12/93, zagreb. 7 benamati∆, d., dujmi∆, d., kasapovi∆, s., pe©t, d. & salkovi∆, a. (1997): kompenzacijski bazen gusiê polje, geofiziëka istraæivanja.unpubl. report, archive of moho, zagreb 8 pe©t, d. (1999): kompenzacijski bazen gusiê polje, mjerenje vlastitog potencijala.unpubl. report, archive of moho, zagreb. 94 geologia croatica 55/1 suring on the whole area of the basin was foreseen. conducting of self potential measuring was planned during the normal work of the power plant in a basin full of water. geoelectrical methods were chosen, because of their speed and of the non-destructive characteristics of indirect (surface) investigations. 2. hydrogeological relations the area of gusiê polje is built of limestones of jurassic age with interbeds and lenses of dolomite (veli∆ et al., 1974). there were clays deposited on them, with thickness up to several metres, depending on the palaeorelief of the polje. the clays are covered with younger travertine-silty deposits of variable degrees of lithification. the average thickness is 1-2 m. the permeability of silty travertine is k = 10-4 c m / s and of clay is k = 106 to 107 cm/s. clayey marls are determined as impermeable rocks. during the remediation it was seen that inside the silty travertine small channels could develop and on the border with clay, the concentrated flow of groundwater towards the ponors (suffosions) could emerge. newly formed ponors and suffosions appear in the part of polje where the quaternary deposits have the greatest thickness. once repaired the appearance of sinking in that part of polje usually reappears. the existing water level data show sudden decrease of water table in the area with thick marl clays, which exist up to 396 m above sea level, i.e. 36 m below the surface of polje. upstream from this clay barrier, water levels are always higher than at this spot height. downstream, before the construction of the basin, the lowest level was ten or more meters below that spot height, and the highest one was in the level of polje (around 432 m above sea level). today the differences between minimum and maximum levels downstream of the deepest clays are smaller and they differ in range from 386 to 413 m above sea level, and exceptionally between 364 and 377 m above sea level along the south border of polje. geomorphological processes, which led to the present hydrogeological characteristics of gusiê polje, are connected with karstification of the wider area and the escarpment of the gacka karst river, which flows through the polje. the first ponors in gusiê polje were developed during the modelling of palaeorelief (at the end of pleistocene), before the deposition of quaternary sediments (prelogovi∆, 1989; pavi»i∆ & reni∆, 1992). it was then that the basic underground drainage net was developed. the depth of karstification was gradually increased, and in the dry period the water level decreased over 50 m below the polje. due to the erosion of the clay material through the canals of ponors in weathered rock, the unstable conditions in quaternary deposits began (pavi»i∆ & fritz, 1995). at sudden changes of groundwater level the conditions for appearance of pressure and under pressure exist. they have probably greater values after the clay carpet was made, because natural ventilation conditions were changed. washing out of clay and travertine silt on the contact with the palaeorelief increased as well as the genesis of holes that lead to caves in ponors (fig. 2). the water holding capacity of the basin, based on the water holding of quaternary deposits, was not realistic. by subsequent construction of the clay carpet, the losses were reduced, and additional losses are attributed to lack of clay carpet below the supply canal and fig. 1 location map and hydrogeological map of the gusiê polje reservoir. legend: 1) ponor (swallow hole); 2) suffosion phenomenon; 3) suffosion ponnors: a) hole appeared once, b) hole appeared twice, c) hole appeared many times. accompanying embankments and locally to an incomplete clay carpet in the basin. shallower suffosions along the canal and accompanying embankments, after the remediation do not reappear. the majorities of ponors (suffosions), that appear, that are repaired and then reappear, are inside quaternary deposits thicker than 6-7 m, i.e. inside the depressions in palaeorelief, which is connected with reactivation of old ponors, that have been active before the sedimentation of quaternary deposits. at the same time, these are basic dangers for water losses and genesis of cave in ponors (pavi»i∆, 19929). without the investigations within the area of the basin, a method of complete remediation of the basin is impossible to perceive. due to the short period of time when the basin is empty (during the annual repair) it was necessary to select the geophysical method of investigations that can be applied when the basin is full of water. therefore, with methods that are conveyed on dry land, the self potential method was successfully used. 3. geophysical investigations during the repair of the plant the investigation of the bottom of basin clay carpet, was carried out using non-destructive geoelectrical methods (benamati∆ et al., 2000). on the old accumulation (g.p.i.), the investigation of the thickness of artificial clay carpet was carried out, in the conditions of empty accumulation, using geoelectrical profiling and wenner electrodes, at five levels of depth. the tectonic structure of the polje beneath the bottom of the basin (carpet and bedrock) was investigated with a net of geoelectrical sounds with ab/2=50 m with schlumberger position of electrodes, because the geology of the polje was known from previous investigations. in conditions when accumulation was full the measuring of spontaneous potential was carried out. the aim of this method was to locate the positions where the water was lost, in order to establish zones in the accumulation area, for the design of basin remediation. realization of new accumulation on the part of the polje outside the present accumulation, with similar hydrogeological conditions, was considered as an alternative solution. on that future accumulation, the undisturbed systematic investigations are possible, as well as solutions, based on experience in karst terrains and previous investigations for a new basin. 3.1. resistivity sounding and geoelectrical profiling resistivity sounding should determine the thickness of quaternary deposits (travertine, clay and calcareous clay) with poor geotechnical characteristics. according to present acknowledgments, new ponors and suffosions occurred in the part of the polje where the quaternary deposits are thickest, i.e. inside the depressions in palaeorelief, as the result of reactivation of old ponors, which were active before the sedimentation of quaternary deposits. for that purpose some 200 geoelectrical measurements with schlumberger position of electrodes ( ab/2= 50 m ) were conducted over the whole basin area, positioned in rectangular net with inner distances of 40 m. figure 3 shows the characteristic geoelectrical cross-section gp-21. the results of sounding confirmed the existence of distinguished palaeodepression in carbonate bedrock and determined its strike. according to 95paviëiê, benamatiê, peπt & marasoviê: water reservoir within the karst field... fig. 2 ponor within the gusiê polje reservoir. 9 pavi»i∆, a. (1992): sanacija kompenzacijskog bazena gusiê polje hidrogeoloπki radovi.unpubl. report, archive of inst. of geology, 80/92, zagreb. 96 geologia croatica 55/1 these results, ponors are connected to the drainage net from the time of palaeodepression, which is at present time the basis for groundwater outflow from gusiê polje. however, smaller ponors (suffosions) appear on the surface outside the deepest parts of the palaeodepression, but they are connected with ponors inside the palaeodepression. the priority of geoelectrical profiling was to determine the condition of the protective rock aggregate and clay carpet. according to the design, a protective rock aggregate (with thickness of 15 cm) and impermeable clay carpet (with thickness of 30 cm) were constructed over the whole area of the basin. it was foreseen that the mud thickness is around 10 cm. such an arrangement of layers is favourable for geoelectrical investigation methods, because between two layers with low resistivity (clay and mud) there is a layer with high resistivity (protective rock aggregate). geoelectrical profiling was adapted to such, expected, arrangement of layers: five spacing of electrodes (depths) 0.25, 0.5, 1.0, 2.0 and 4.0 m. geoelectrical profiling was conducted on 1540 measuring locations positioned in rectangular net with sides 20 x10 m, covering the whole area of the basin, except the inflow canal and accompanying embankments. the computer controlled measuring instrument with wenner offset arranged electrodes was used for five mentioned depth ranges. in this way the average efficiency of 180 measuring points per day was accomplished, which is significant because of the limited period of access to the basin during the plant repair. the biggest problem during the measurement and interpretation of results was the fact that the humus sediment on the rock aggregate was significantly thicker than the predicted 10 cm. locally, along the edge of the supplying canal, it reached values of 70 cm. sediment 40 cm thick physically slowed measuring and during the interpretation it decreased the expected differentiation of layers, because of the relatively smaller thickness of the remaining two layers. therefore, the planned range to investigate depth lost the initial objective, because the first of depth of 0.25 m stayed in the layer of humus. the measuring results were supposed to isolate zones of damage in rock and clay layers with tendency to form a ponor. however, the results suggested that the cause of water loss was not damage, but an incomplete protective carpet on the bottom of the basin and along the central embankments. according to the measuring results (fig. 4) in the northeast part of basin, low values of resistivity, which correspond to the clay carpet were not recorded. measured high values were not from protective rock aggregate, but from indigenous travertine cover below the humus layer. as this part of the basin is on higher spot heights than the rest, and as it is not always under water, the ponors do not emerge here, but water probably seeps through travertine not allowing further filling of the basin. similarly along the base of the inner embankments, resistivities that correspond to the protective clay carpet were not recorded. this is in accordance with the facts that the majority of new ponors appeared along the base of the inner embankments, and that those embankments were built before the clay carpet was placed on the bottom of the basin. the above mentioned conclusions should be verified through direct investigations. the results of geoelectrical profiling were reinterpreted as small geoelectrical sounds to better determine fig. 3 the characteristic geoelectric profile (gp-21) with results of geoelectric profiling (upper part) and vertical electrical sounding (bottom). legend: 1) 20-1400 ωm, surface layer; 2) 25-70 ωm, quaternary deposits; 3) 65-420 ωm, limestones; 4) fault determined by geological and geophysical investigations. 97paviëiê, benamatiê, peπt & marasoviê: water reservoir within the karst field... the extent of particular materials in the surface part of the bottom of the basin. a hypothetical model of extent of particular materials, with variable layer thickness and resistivity, was used. in this way we obtained the spatial arrangement of real resistivities, by which the possible areas of protective layer damage were isolated as layer discontinuities. this procedure did not show new, significant areas of damage, besides those already isolated, but it enabled easier inspection of the measured results. on fig. 3 the extension of particular sediments can be traced below the protective layer and separating the areas of low resistivity with clay sediments, from the areas of high resistivity, where travertine deposits are just below the protective layer. 3.2. self potential to determine the dominant directions of groundwater seepage and zones of water sinking from the basin, the measuring of self potential through the whole area of basin was foreseen. conduction of measurement was planed during the normal work of the power plant with the basin full of water. measuring of self potential was conducted on 1680 locations positioned into rectangular net dimensions 10x20 m, covering the whole area of basin. by that, one electrode was used as a reference point outside the basin and the other electrode was lowered to the bottom of the basin. the characteristic fact for this type of investigation was the low deviation of the measured values during the study (the values were “calm” and “stable”) and showed only a small variation along the cross section (low gradient of sp). calculated values of sp are shown on the map of self potential field (fig. 5), which shows that the canal is clearly distinguished with lower values of potential (dark) and some anomaly minimums. low values of potential are zones from where the water is sinking into the lower areas. because the water is above the ground in this case, the areas with minimum values of potential would be the places of sinking of water into the ground. anomalies of especially low values of potential do not have to mean that the sinking is proportionally expressed at those locations. in contrast, it is interesting to notice that mainly greater values of potential are recorded on the accompanying embankments in regard to other areas. this indicates seepage of water from the surrounding areas towards the embankments. the same is valid for the outer embankments toward which the values of potential increase. besides, on the areas of additional basins (north and south) there are no anomalies in potential values, but the recorded values are uniform leading to the conclusion that no new ponors have emerged in those areas. if we compare the results of geoelectrical profiling and self potential, we can conclude that the area of increased resistivity (dark) follows the area of increased potential fairly well, especially along the north edge of the basin. there, the zone of low resistivity, extending like a narrow band, is identical to the local minimum of self potential. consequently, the locations of high resistivity are the zones towards which the groundwater flows, probably through the surface layer. this confirms the presumption that the clay carpet was not constructed on that location. the investigations for a new basin have been completed. the refraction survey, gama and gama-gama logging were used among the methods of applied geophysics. the goal of the geophysical investigations was to separate the cover deposits from the bedrock (refractor). the whole polje was covered with 135 spacings of 100 metres, set in 21 profiles, which enabled the investigation down to a depth of 40 m. on the basis of the fig. 4 the results of geoelectrical tomography for depth level of 0.5 m. the dark tone represents sector with high electrical resistivity, and therefore it belongs to the zone where clayey carpet is damaged or missing. 98 geologia croatica 55/1 refraction survey in a new basin, 9 investigation boreholes were located, to verify and correlate borehole and seismic data. using the results of the refraction survey, maps of surface complex thickness (cover) were made, as well as a map of deposit thickness above the hard basic carbonate rock massif. also, a map of velocities in upper part of basic rock massif was produced, which includes the velocity range from 1400 to 4000 m/s. the anomaly zones are controlled with the borehole next to the recently active ponor on the surface, which verified the anomaly connected to the palaeorelief filled with travertine, which is in direct contact with the basic rock with poor mechanical characteristics and good permeability. 4. suggested remediation solutions 4.1. remediation of the existing basin based on the investigation results, it is determined that the highest seepages are in the area of the canal, which is covered with concrete plates under which a protective clay layer was not constructed. due to the fact that investigations inside the basin are possible only during the annual one month reparation of the plant, the solution was chosen for remediation of the canal area, which can be performed in phases over several years. the economic-technical comparison of various possible solutions led to the choice of a method, that includes construction of a protective impermeable cover of the canal, made of foil which is laid on a geotextile layer with a density of 300 g/m2 over the existing concrete plates of canal (fig. 6). the foil is anchored in the canal bottom and on the slopes of accompanying embankments, where the connection between foil and clay carpet, in the form of a 5 m wide overlap is made. the foil of chd type is chosen (modified phd polyethilene high density foil used for potable water) due to ecological requirements, because water from the basin is also used for the public water supply. in the areas inside the basin, where geophysical investigations determined the possibility of water loss or discontinuity of a clay carpet, a new clay carpet or the strengthening of the existing one is foreseen. the fig. 6 gusiê polje canal crosssection. fig. 5 the spontaneous potential map. supposed groundwater flow is from dark toward white areas. 99paviëiê, benamatiê, peπt & marasoviê: water reservoir within the karst field... whole remediation implies incorporating about 100,000 m2 of foil and construction of about 120,000 m2 of new clay carpet. the mentioned quantity of works is planned for a two year period during the annual interruption of plant work. 4.1. building of a new basin due to the increase of installed flow of hp senj, the building of a new compensation basin, 2.0 mil. m3 i n volume, is planned, next to the existing basin (fig. 7). this basin is planned to be built on similar geological foundations. assurance of the water holding capacity of the basin bottom and embankment slopes was taken into consideration in the variant of using artificial materials and clay (fig. 8). in the vicinity of the basin there is a source with sufficient quantities of quality clay, the economic-technical comparison of variants showed the worthiness of constructing the clay carpet with a thickness of 50 cm. the clay carpet is laid on the geotextile layer with the density of 500 g/m2, which is laid on the neat and compacted bottom of the basin. it is also foreseen that the layer of geotextile with density of 500 g/m2 will be laid on the surface layer of clay and then covered with layer of crushed rock 30 cm thick. the geological investigations determined several faults in the basin area, which in case of sudden changes in the groundwater level, could alter the pressure on the bottom of the basin. therefore the possibility for draining the air below the clay carpet is foreseen, using the system of drainage tubes which are laid along the faults with exits on air slopes of embankment. according to the available data on groundwater levels in the basin area, it could be considered that there would be no elevation of groundwater above the basin bottom, which, together with the aeration system, assures stability of the basin bottom. 5. conclusion by realization of surface accumulation in the karst polje, the water holding capacity of which is based on the impermeability of the quaternary clayey-silty deposits, one should take into account the stability of the quaternary cover. therefore during the preliminary design phase, it is necessary to carry out extensive investigations to learn about the genesis of the terrain, hydrogeological relations and hydrological conditions that were present in the creation of the polje, as well as after the sedimentation of quaternary cover. besides surveying boreholes and measuring groundwater levels, it is necessary to perform geophysical investigations to estimate the thickness and lithological composition of the cover, as well as the condition and karstification of the carbonate bedrock. to solve the problem of the water holding capacity of the basin and remediation of losses through suffosions in already existing basins, geoelectric investigation methods have proved to be suitable in the conditions of exploitation when the investigation is time limited and the bottom of the basin is covered with soft deposits. the self potential method applied on the basin filled with water recorded traces of water seepage and sinking. the results of geoelectrical methods and self potential method separated problematic areas, the primary one being the canal zone and accompanying embankments, where increased values of resistivity and anomfig. 7 gusiê polje basins layout. 100 geologia croatica 55/1 aly values of potential were recorded. this confirms that in this particular location the clay carpet was not fully constructed and water seeps toward that area. in the central parts of the accompanying basins the anomalies of self potential that would suggest the appearance of new ponors were not recorded, but according to geophysical investigations no significant damage of the clay carpet was recorded. it should be emphasized that the biggest problem for realization of the water holding capacity of surface accumulations in the karst polje is the stability of the bottom of the basin, because water holding can be solved with artificial materials, but without stability of the foundation, there is no permanent solution for undisturbed exploitation of the object. 6. references benamati∆, d., pe©t, d. & pavi»i∆, a. (2000): doprinos geofiziëkih istraæivanja pri lociranju gubitaka vode iz bazena gusiê polje.in: vlahovi∆, i. & biondi∆, r. (eds.): 2nd croatian geological congress, cavtat-dubrovnik, proceedings, 525-530, zagreb. pavi»i∆, k. (1986): teπkoêe u radu kompenzacijskog bazena gusiê-polje i njihovo uklanjanje.energija, 35/4, 275-278, zagreb. pavi»i∆, a. & fritz, f. (1995): water holding of compensation basin gusiê polje.in: vlahovi∆, i., veli∆, i. & ©parica, m. (eds.): 1. croatian geological congress, proceedings, 2, 431-434, zagreb. pavi»i∆, a. & reni∆, a. (1992): recent karstification and water drenage from bakovac vally (lika, croatia).int. symp. “geomorphology and sea”, mali loπinj, proceedings, 127-133, zagreb. prelogovi∆, e. (1989): neotektonski pokreti u podruëju sjevernog velebita i dijela like.geol. vjesnik, 42, 133147. veli∆, i., bahun, s., soka», b. & galovi∆, i. (1974): osnovna geoloπka karta sfrj 1:100000, list otoëac, l33-115 (basic geological map of sfrj, otoëac sheet).inst. geol. istraæ., zagreb (1970-1974), sav. geol. zavod, beograd. manuscript received march 05, 2002. revised manuscript accepted may 20, 2002. fig. 8 gusiê polje basin embankments. 1. introduction veliko and malo jezero (the mljet lakes) are natural phenomena on mljet island (adriatic sea). due to its scenic beauty, ecological peculiarities, and environmental values the western part of the island was proclaimed a national park in 1960 (fig. 1). veliko and malo jezero (large and small lake = mljet lakes) are semienclosed depressions connected with the open sea by a narrow, shallow channel. the lakes are typical karst depressions (d o l i n e s or sinkholes), which were formed under subaerial exposure and are now submerged due to holocene sea-level rise. being connected with the sea, they have saline marine water and therefore are not true lakes, but can be termed marine lakes. morphometric characteristics of the mljet lakes were reported in vuleti∆ (1953), along with their geological setting and sediment characteristics. benthic foraminiferal assemblages in a restricted environment an example from the mljet lakes (adriatic sea, croatia) vlatka vani»ek , mladen jura»i∆ , zlatan bajraktarevi∆ and vlasta ∆osovi∆ weak tidal currents and feeble wind influence cause expressed stratification of the water column, giving rise to temporary stagnant conditions in the marine lakes, especially in malo jezero (buljan & ©pan, 1976; benovi∆ et al., 2000). therefore the mljet lakes are restricted environments not only in a spatial sense, but also in the sense of stress-producing factors (seibold & berger, 1996). the aim of this preliminary research was to compare benthic foraminiferal assemblages, including foraminiferal morphological variations, with hydrological, sedimentological, and ecological characteristics of such a peculiar, restricted, unstable environment in the karstified marine depressions. in spite of the worldwide distribution of karstic phenomena, there are very few papers dealing with the various organisms inhabiting such areas (cimerman et al., 1988; soka» & bajraktarevi∆, 1995). cimerman et al. (1988) found two different foraminiferal assemblages in veliko jezero. in coarsegrained sediment at 30 m depth miliolids occurred in large number, while in the muddy bottom (at 42 m depth) agglutinated foraminifera were dominant, implying low temperature, low oxygen content and reduced light (i b i d, p. 745). in contrast, soka» & bajraktarevi∆ (1995, p. 130) have described in the same marine lake, but at 8 m depth in the >250 µm size fraction a typical shallow-marine foraminiferal assemblage with a prevalence of porcellaneous and agglutinated species. in a sample from 30 m depth they found that hyaline foraminifera dominate the assemblage. salinity data in this paper are reported simply as numbers, because the salinity has been defined since the early 1980’s as the ratio between conductivity of seawater and of standard kcl solution (open university course team, 1989). 2. study area 2.1. hydrography water exchange between the open sea and veliko jezero and malo jezero is driven by tidal currents. however, the average tidal amplitude in this area is only 11±0.5 cm (buljan & zore-armanda, 1976). the veliki most (large bridge) strait between g eol. croat. 53/2 269 279 3 figs. 6 tabs. zagreb 2000 key words: benthic foraminifera, anoxia, restricted environment, e l p h i d i u m, h a y n e s i n a , mljet island, adriatic sea, croatia. department of geology, faculty of science, university of zagreb, zvonimirova 8, p.o.box 332, hr-10002 zagreb, croatia. abstract benthic foraminiferal assemblages from a peculiar restricted marine environment, the mljet lakes (mljet island, adriatic sea, croatia) have been studied. these lakes are drowned karst dolines, which are connected with the adriatic sea through a narrow, shallow channel. occasional stagnant conditions in the marine lakes cause hypoxic and anoxic conditions in the bottom waters. such stressed conditions are reflected in oligospecific benthic foraminiferal assemblages with a shannon-wiener species diversity index (h) ranging from 0.8 to 1.0 and equitability index (e) ranging from 0.18 to 0.26, identified in samples from each marine lake. in the more dysoxic malo jezero, haynesina depressula dominates an assemblage of 12 benthic foraminiferal species. in the less (and less frequently) hypoxic veliko jezero, we found an asterigerinata mamilla a s s e m b l a g e with 18 foraminiferal species. a more diverse assemblage containing 55 different benthic foraminiferal species occupies an adjacent opensea station. long-term salinity measurements indicate that h. depressula tolerates higher salinity than formerly presumed (up to 38‰), and is well adapted to stressed hypoxic conditions. 270 geologia croatica 53/2 the soline channel and veliko jezero is only 10 m wide and 2.5 m deep. prior to artificial enlargement in 1960 it was only 4.5 m wide and 0.6 m deep (straæi»i∆, 1979). the mali most (small bridge) strait between veliko and malo jezero is even smaller: 2.5 m wide and 0.2 m deep. therefore the masses of water exchanged are small. mean annual precipitation (19811990) at the nearby meteorological station goveari is 765 mm, and potential evapotranspiration is 692.6 mm/year, indicating the slightly humid climatic characteristics of the region. however, precipitation is concentrated in winter, whereas during summer evaporation prevails (vu»eti∆ & vu»eti∆, 1995). therefore, during the warm part of the year, due to excessive heating of the surface layer, large differences in density between surface and bottom waters occur. dense bottom water formed in winter cannot be exchanged during summer. the concentration of organic matter increases in summer, and this causes enhanced bacterial degradation and oxygen undersaturation in the deepest parts of the mljet lakes (cari∆ & jasprica, 1995). the summarized hydrographic data (table 1, after buljan & ©pan, 1976; benovi∆ et al., 2000) indicate high salinity (36-38 ‰), relatively cold water (9 18°c), and episodic anoxic conditions in bottom water in both depressions (in malo jezero and in veliko jezero). for example, buljan & ©pan (1976) report that in 1951 to 1953 there was a permanent anoxia in the bottom waters in the malo jezero. benovi∆ et al. (2000) found that dissolved oxygen saturation near the bottom in october 1997 was 4.3% in malo jezero and 17% in veliko jezero. moreover, they registered an anoxic event in the veliko jezero between august 26 28, 1996, when below the thermocline layer (at 18.5 m) oxygen concentration rapidly decreased to 0% in the layer from 39 m to the bottom. open marine hydrographic conditions were found at the kriæ station (figs. 1, 2). due to vertical differences in temperature and salinity, the formation and depth of the seasonal thermocline differs at the locations investigated. in the open waters of mljet island (kriæ station), the seasonal thermocline depth ranges between 11 and 42 m and its average depth is at 25 m. in veliko jezero, the thermocline is shallower (12 -22 m) and shows little vertical change. in malo jezero, the thermocline is the shallowest (5-12 fig. 1 map of mljet island, croatia, showing the study area and sampling stations. m), but also the most stable and the strongest, because of large temperature differences (fig. 2). occasionally, the thermocline formed during summer in malo jezero remains stable even during winter, thus preventing bottom water mixing for a period longer than a year (buljan & ©pan, 1976). 2.2. sediments previous sedimentological research in the mljet lakes (vuleti∆, 1953; seibold, 1958; cimerman et al., 1988; jura»i∆ et al., 1995) indicated similar sediment distribution in both lakes. the deepest part of malo jezero is covered with muddy sediment, whereas the bottoms above 17 m contain mainly zoogenous sand. a change in sediment type with depth can also be observed in veliko jezero, but it is not as regular as in malo jezero. the shallower parts of veliko jezero are covered with biogenous carbonate sands, whereas in the deeper parts (42 m) clay minerals and authigenic pyrite are present. in sediment cores taken from both malo jezero and veliko jezero, microlamination is common. the laminae have been interpreted either as annual layers (varves) as a consequence of seasonal anoxic conditions (seibold, 1958; seibold & berger, 1996), or 271vaniëek, juraëiê, bajraktareviê & ∆osoviê: benthic foraminiferal assemblages in a restricted environment... stations 1. malo jezero 2. malo more 3. veliko jezero 4. soline channel 5. kriæ (28 m) (13 m) (40 m) (1.5 m) (open sea) (38 m) salinity 36-38 34-36 35.5 -37 36-38 38 temperature 9-18 °c 9 -28 °c 9-17 °c 9-27 °c 13-16 °c oxygen concentration 0.0 -6.6 ml/l 4.8 -6.4 ml/l 0.0-6.6 ml/l 5 -6 ml/l 4.2 -6.6 ml/l table 1 ranges of bottom water characteristics at investigated stations. summarized data after buljan & ©pan (1976) and benovi∆ et al. (2000). fig. 2 schematic profile through the mljet lakes showing annual oscillation of temperature and the position of the thermocline, bottom sediment type, and prevalent distribution of morphotypes of elphidium crispum (a = morphotype #1; b = morphotype #2) and occurrence o f elphidium aculeatum (c). scale bar is 200 µm. 272 geologia croatica 53/2 lamination due to episodic bottom-water anoxic events which need not necessarily correspond to annual variations (jura»i∆ et al., 1995). 3. sampling and methods 3.1. sampling and sample preparation scuba divers collected sediment cores up to 80 cm long from five stations in the mljet lakes and the adjacent open sea (fig. 1) in may 1995. sediment cores were frozen within 4 hours, and transported frozen to the laboratory. in the laboratory, frozen cores were cut into subsamples, and the first 2-cm subsamples were used for our research. after defrosting, a subsample of 10 ml of wet sediment was taken for foraminiferal analysis, and the rest of the subsample was used for grain-size analysis. 3.2. methods the grain size of the sediment samples was analyzed by wet sieving, using astm standard stainless steel sieves for >32 µm fraction. a coulter counter (mod. ta ii) was used for the <32 µm sizes. the sediments were classified according to their gravel sand mud (mud = silt + clay) ratio (folk, 1954). carbonate content was determined volumetrically by measuring co2 evolved by dissolving a 0.5 g dry sample in 15% hcl. the subsamples for foraminiferal analysis were stained with rose bengal (murray, 1973), in spite of the disadvantages and limitations of this method (murray, 1991; jorrisen et al., 1995). after staining, subsamples were wet sieved through 250 and 125 µm sieves. in each sample foraminifera were identified after foraminiferi padani (1982), jorrisen (1988), loeblich & tappan (1987), and cimerman & langer (1991), and all specimens (stained and unstained) were counted. the absolute abundance in 10 ml, and the relative abundance of each species was determined. for each station, dominant and accessory species were defined according to their relative abundance. an estimation of the species diversity was performed using the following parameters: number of species, number of specimens, shannon-wiener species diversity index (h), equitability index (e) (buzas, 1979), and percentage of miliolina (=p o r c e l l a n e o u s ) , textulariina (=agglutinated) and rotaliina s . l . (=h y aline). species diversity and abundance were compared with the known ecological conditions (temperature, salinity, substrate). the morphotype variations were described from >125 µm size-group foraminifera. existing corollary hydrographic data gave a better understanding about the ecological affinity of investigated species. sedimentation rate was estimated according to the relative abundance of specimens of sessile species (poag et al., 1980). 4. results 4.1. granulometric analyses results of granulometric analyses (mean size, sorting, mud percent, and sediment type), along with carbonate content of investigated samples, are reported in table 2. the sample from the deepest part of malo jezero (sample # 1; 28 m depth) has only 4.9% biogenous particles/fragments of gravel and sand size, and the rest is silt and clay. the surface sediment is 71% carbonates, mostly aragonite, with lesser amounts of calcite, magnesian calcite, and dolomite. the remaining part is quartz and feldspar (sondi et al., 1995). in the shallow part of malo more (sample # 2; 13 m depth), the water mean sorting mud sediment carbonate sample depth size, mz so (%) type (%) (m) (µm) (folk, 1954) 1. malo 1.61 slightly jezero 28 10.9 poorly 95.1 gravelly 72 sorted mud 2. malo 2.81 slightly more 13 176.8 very poorly 48.4 gravelly 89 sorted sandy mud 3. veliko 3.45 gravelly jezero 40 59.5 very poorly 73.3 mud 62 sorted 4. soline 1.44 gravelly channel 1.5 692.6 poorly 5.1 sand 76 sorted 5. kriæ 2.02 gravelly (open sea) 38 1659.8 very poorly 12.2 muddy 59 sorted sand table 2 granulometric properties, types of sediments, and carbonate content. surface sediment sample (0-2 cm), mljet, may 1995. 273vaniëek, juraëiê, bajraktareviê & ∆osoviê: benthic foraminiferal assemblages in a restricted environment... sediment has 51.5% biogenous gravel and sand; the remainder is mud. sample # 3 (40 m depth) in veliko jezero contains 26.5% biogenous particles (>125 µm). the bottom of the shallowest part of the soline channel (sample # 4; 1.5 m depth) contains carbonate gravely sand, which forms symmetrical ripples. their wave lengths are 3 -6 m, as a consequence of the relatively strong tidal currents in that shallow channel. sediment sorting is therefore better than in other samples (although still low =1.44). the nearshore marine sample # 5 (kriæ, 38 m depth) had the largest mean size (1660 µm), with 21.42% gravel, 66.43% sand, and the minimum carbonate. 4.2. diversity of species and assemblages, morphotype variations, and sedimentation rate the numbers of stained, unstained, and total specimens, along with the number of species present in each sample, are reported in table 3. in total, 67 benthic foraminiferal species were determined, and 44 species were represented by stained specimens in at least one sample (table 4). the ratio between unstained and stained specimens (u/s) varies from 10:1 (# 1 and 2) to 4:1 (# 4) (table 3). six species were found only in the marine lakes, and 10 were restricted to the open water. dominant and accessory species were determined at each station (table 5). in table 6 the shannon-wiener index (h), equitability index (e), and percentage of textulariina, miliolina and rotaliina are shown. in the sample from malo jezero (station # 1; 28 m depth), we found 12 species, represented by only 132 specimens in the standard 10 ml sample. the u/s ratio is high (10:1). the majority of foraminifera belongs to the suborder rotaliina (77% ). the specimens of miliolina are rare. this association is characterized by thinwalled species (sizes less than < 250 µm): h a y n e s i n a d e p r e s s u l a , asterigerinata mamilla , valvulineria bra dyana. h index is the lowest of all samples (0.81), while the e index is 0.22. we refer to this association as the haynesina depressula assemblage (table 5). at 40 m depth in veliko jezero (station # 3), we found the asterigerinata mamilla assemblage (table 5). this sample contains 18 species and 146 specimens, almost entirely belonging to the rotaliina (91 % ) : a . m a m i l l a, v. bradyana , h. depressula , rosalina bradyi and a large elphidium crispum (tables 3, 4). u/s ratio is low (5 :1), and h and e indices are low (0.97 and 0.23 respecively). in malo more and in the soline channel we found a foraminiferal fauna different from that in malo jezero and veliko jezero. in malo more (station # 2; 13 m depth), 32 species and 978 specimens were determined (u/s = 10:1, h= 0.91, e = 0.18), and in soline channel (station # 4; 1.5 m depth), 38 species with 1810 specimens were counted (u/s = 4:1, h =1.23, e= 0.23) (tables 3, 6). we assigned benthic foraminiferal assemblages in malo more to the peneroplis planatus assemblage, whereas the peneroplis pertusus a s s e m b l a g e characterizes the station in soline channel (table 5). in malo more, p. pertusus and p. planatus p r e v a i l and constitute about 60% of the foraminiferal assemblage, along with small rotaliina: epifaunal a. mamilla and infaunal h. depressula . in the soline channel, the same species as in the “lakes” were found (e. crispum, a. mamilla, h. depressula ), along with sessile and attached species (the later are sometimes mobile): cibi cides refulgens, cibicidella variabilis , lobatula lobatu l a , planorbulina mediterranensis , r. bradyi, g a v e l i nopsis lobatulus. the open sea kriæ sample (station # 5; 38 m depth) was the only one in which t e x t u l a r i i n a exceeded 1% . the rosalina bradyi cibicides refulgens a s s e m b l a g e contained 55 species with 876 specimens (h = 1 . 4 8 , e= 0.26) (tables 3, 5, 6). biogenous fragments form an ideal substrate for such sessile species. beside r. bradyi and c. refulgens, the sample contained g. lobatulus , a. number of dry specimens unstained stained ratio total sample weight in gram of species specimens specimens u/s specimens in 10 ml (g) sediment (u) (s) 1. malo jezero 8.29 15.9 12 120 12 10:1 132 2. malo more 9.59 102.0 32 887 91 10:1 978 3. veliko jezero 6.29 23.2 18 122 24 5:1 146 4. soline channel 9.23 196.1 38 1462 348 4:1 1810 5. kriæ (open sea) 10.02 87.4 55 771 105 7:1 876 table 3 number of species, unstained and stained individuals and total number of specimens in each sample, mljet, may 1995. 274 geologia croatica 53/2 stations 1. malo 2. malo 3. veliko 4. soline 5. kriæ jezero more jezero channel (open sea) unstained stained unstained stained unstained stained unstained stained unstained stained foraminifera no. % no. % no. % no. % no. % no. % no. % no. % no. % no. % total 120 100 12 100 887 100 91 100 122 100 24 100 1462 100 348 100 771 100 105 100 textulariina textularia sp. 1 0.11 1 0.9 11 1.4 miliolina vertebralina striata 21 2.4 1 1.1 8 0.6 1 3 3 0.4 adelosina mediterranensis 3 0.3 10 1.3 spiroloculina ornata 7 0.8 2 2.2 2 0.1 1 0.3 14 1.8 3 2.9 siphonaperta aspera 9 1.0 72 4.9 18 5.2 cycloforina contorta 3 0.2 5 0.7 c. juleana 10 0.7 4 0.5 c. villafranca 3 0.4 2 1.9 c. colomi 1 0.1 lachlanella variolata 1 0.1 10 0.7 4 1.2 1 0.1 massilina secans 1 0.1 1 1.0 m. gualtieriana 1 0.1 quinqueloculina nodulosa 4 0.5 2 0.1 23 3.0 q. laevigata 18 15 3 25 29 3.3 8 8.8 3 2.5 11 0.8 9 1.2 1 1.0 q. limbata 3 4 q. stelligera 8 1.0 q. jugosa 2 0.6 24 3.1 q. parvula 3 2.5 25 2.8 188 13.0 9 2.6 17 2.2 3 2.9 q. bidentata 36 2.5 6 1.7 8 1.0 2 2.0 q. seminula 52 3.6 8 2.3 3 0.4 2 2.0 q. ungeriana 6 0.4 3 0.9 6 0.8 1 1.0 miliolinella subrotunda 2 0.3 3 2.9 m. semicostata 2 0.2 3 0.4 1 1.0 m. grata 2 0.1 4 1.2 m. webbiana 1 0.1 pseudotriloculina laevigata 1 0.1 10 0.7 17 2.2 1 1.0 p. oblonga 4 3.3 2 0.2 2 1.6 8 0.6 4 0.5 1 1.0 triloculina marioni 1 0.1 1 1.1 10 0.7 10 1.3 1 1.0 t. schreiberiana 1 0.1 41 3.0 9 2.6 13 1.7 1 1.0 pyrgo sp. 2 0.26 sigmoilinita costata 1 0.1 34 4.41 articulina carinata 1 0.13 coscinospira hemprichii 1 0.1 wellmanelinella striata 2 0.1 laevipeneroplis inornatus 1 0.1 peneroplis pertusus 2 1.7 231 26.0 26 28.6 2 1.6 1 4.17 309 21.1 70 20.1 10 1.3 2 1.9 p. planatus 287 32.4 30 33 1 0.8 1 4.17 288 19.7 54 15.5 7 0.91 p. arietinus 4 0.3 sorites orbiculus 2 1.6 rotaliina lenticulina sp. 3 0.4 polymorphina sp.7 8 1.0 1 1.0 sphaerogypsina globula 9 1.2 bolivina sp. 6 5 1 8.3 1 0.1 1 0.8 elphidium crispum 4 3.3 22 2.5 1 1.1 18 14.8 7 29.2 93 6.4 80 23.0 46 6.0 10 9.5 e. aculeatum 3 0.2 1 0.3 16 2.1 e. sp. 1 1 0.1 1 1.1 3 2.5 10 1.3 e. sp. 4 2 1.7 3 0.3 2 1.6 29 2.0 5 1.4 32 4.2 1 1.0 e. cf. depressulum 4 0. 5 38 2.6 9 2.6 e. cf. maioricensis 1 0.1 7 0.9 planorbulina mediterranensis 1 0.1 6 0.4 3 0.9 6 0. 8 3 2.9 cibicides refulgens 1 0.1 2 2.2 2 1.6 2 8.3 45 3.1 12 3.6 77 10.0 6 5.7 lobatula lobatula 3 0.3 3 2.5 29 2.0 3 0.9 13 1.7 5 4.7 cibicidella variabilis 3 0.2 3 0.9 1 1.0 asterigerinata mamilla 3 2.5 107 12.1 10 11 37 30.3 9 37.5 6 0.4 2 0.6 67 8.7 7 6. 7 gavelinopsis lobatulus 3 2.5 93 6.4 31 8.9 42 5. 5 13 12.4 rosalina bradyi 1 0.8 26 2.9 1 1.1 7 5.7 32 2.2 6 1.7 73 9.5 18 17.1 r. macropora 3 0.4 3 2.9 r. vilardeboana 27 3.5 2 1.9 haynesina depressula 39 32.5 8 66.7 36 4.1 8 8 14 11.5 3 12.5 1 0.3 valvulineria bradyana 20 16.7 7 0.8 21 17.2 1 4.2 2 1.9 eponides concameratus 1 0.1 neoconorbina terquemi 48 6.2 5 4.8 astronion stelligerum 2 0.1 13 1.7 3 2.9 ammonia parkinsoniana 6 0.4 3 0.9 a. tepida 18 15 48 5.4 2 0.3 lagena sp. 2 0.3 buccella sp. 1 8 1.1 275vaniëek, juraëiê, bajraktareviê & ∆osoviê: benthic foraminiferal assemblages in a restricted environment... mamilla, e. crispum and in much smaller amount spine specimens of e. aculeatum. several different species of miliolina were also present (table 4). morphotype variations were only found in the elphidium crispum species (fig. 2). two morphotypes have been distinguished based on the following features (after jorrisen, 1988): (1) maximum diameter; (2) number of chambers per final whorl; (3) structure and ornamentation of the umbilical part of the tests (the presence or absence of defined umbilical boss); (4) degree of inflation of the chambers (their shape); (5) outline of the test. morphotype # 1 of e. crispum species is a thin-shelled, flattened form with the maximum size reaching 1.44 mm, with a high number of arcuate chambers (27-29) in the last whorl, and with 12 14 ponticuli with subelliptical fossettes in last chamber. the sutures are backward curved, with a pronounced umbilical knob with 7 -9 large perforations, and with angular peripheral margin. morphotype # 2 is characterized by thick-shelled, lenticular, inflated tests, the maximum size is up to 0.57 mm; low number of arcuate chambers (10 -14) in the last whorl, 9 -12 ponticuli in the last chamber, the fossettes between ponticuli are rectangular in shape, chambers gradually increasing in size. the sutures are backward curved, with a flat umbilical knob. in malo more and veliko jezero (samples # 2 and # 3 respectively), morphotype # 1 prevails (in sample # 2 morphotype # 1 makes 90% of all elphidiids found at this station, and in sample # 3 it participates with 67%). in sediment samples from the soline channel and kriæ (# 4 and 5), morphotype # 2 strongly prevails (87% and 91% respectively) (fig. 2). along with the distribution of morphotypes of e . c r i s p u m, the occurrence of e. aculeatum is shown in fig. 2. it was found only in samples from stations # 4 , and # 5. bottom sediment type at investigated locations is also presented in fig. 2. the percentage of specimens of attached species c i b i c i d e s, rosalina and planorbulina differs significantly from station to station (fig. 3). in malo jezero, specimens of these species were not recorded, but toward the open sea their percentage significantly increases, up to 11.7% in the unstained assemblage and 1 4 .7% in the stained assemblage at the station kriæ. the percentage of sessile specimens in the stained table 4 benthic foraminiferal abundance. surface sediment sample (0-2 cm), mljet, may 1995 (numbers of stained individuals are given in the right column and numbers of unstained are given in the left column for each station). unstained assemblages stained assemblages stations dominant secondary dominant secondary species species species species 1. malo jezero haynesina valvulineria haynesina quinqueloculina depressula bradyana, depressula laevigata ammonia tepida, quinqueloculina laevigata 2. malo more peneroplis peneroplis peneroplis peneroplis planatus pertusus, planatus pertusus, asterigerinata asterigerinata mamilla mamilla 3. veliko jezero asterigerinata valvulineria asterigerinata elphidium mamilla bradyana, mamilla crispum elphidium crispum, haynesina depressula 4. soline channel peneroplis quinqueloculina elphidium peneroplis pertusus, parvula crispum pertusus, peneroplis peneroplis planatus planatus 5. kriæ (open sea) cibicides asterigerinata rosalina elphidium refulgens mamilla, bradyi crispum, gavelinopsis gavelinopsis lobatulus lobatulus table 5 dominant and secondary species of benthic foraminifera in samples from each station. surface sediment sample (0-2 cm), mljet, may 1995. 276 geologia croatica 53/2 assemblage is larger than the percentage of sessile specimens in the unstained association, contrary to the majority of vagile species. 5. discussion as expected from physiographic and hydrographic data, the benthic foraminiferal assemblages show large differences. the ratio of miliolina, textulariina and rotaliina (table 6) indicates that the assemblages from stations located in the “lakes” (stations # 1 and 3) display characteristics of lagoon assemblages (murray, 1991), whereas the assemblage at the marine nearshore station kriæ (station # 5) indicates a normal marine environment with salinity over 30. the smallest number of species and specimens in a standard 10 ml sample was found in malo and veliko jezero (samples # 1 and 3). such assemblages are oligospecific (showing low species diversity and low abundance), but at the same time have high species dominance. generally, they indicate a specific, restricted environment with stressed conditions (oxygen depletion, unusual temperatures, low or high salinity or their large variations). sen gupta & machain-castillo (1993) found that in dysoxic conditions typically 2-3 species constitute up to 80% of the total assemblage. we infer that the primary limiting factor for low species abundance, low species diversity, and high dominance in the mljet lakes is episodic low oxygen concentration (table 1). the oxygen depletion of bottom water is produced by density stratification; in malo jezero the thermocline occurs between 5 and 12 m depth and in veliko jezero between 12 and 22 m depth. both samples show that the fauna have three species making up to 64% of the total (unstained and stained) assemblage; h. depressula , v. bradyana and a. tepida represent 64% of total assemblage in sample # 1; a . m a m i l l a, v. bradyana a n d e. crispum make 63% of total assemblage in sample # 3. in these samples the second dominant species is v. bradyana (making up to 15% of total assemblage at each station), an oxygen deficiency tolerant species (jorissen, 1987, p. 32). this species is absent in samples # 4 and 5. the species diversity index h for total (stained and unstained) assemblages increases from about 0.8 in sample # 1 to 1.4 in sample # 5. lower values found in samples # 1, 2 and 3 are the result of a high dominance of very few species (table 5). the highest value (sample # 5) implies that more favourable conditions for foraminiferal diversity exist in the open marine environment. the equitability index e is very low ranging from 0.18 in sample # 2 to 0.26 in sample # 5. this implies that all the samples are from somehow restricted environments. reoxygenation of bottom water after episodic deficiencies in the mljet lakes, as in other environments, is followed by colonization of benthic foraminifera. shallow water foraminifera require only about three weeks to colonize the substrate and to stabilize their density (buzas, 1993, p. 158). amongst many genera, representatives of q u i n q u e l o c u l i n a and e l p h i d i u m are considered to be colonization pioneers. their presence in all samples does not allow determination of whether foraminifera lived through the low oxygen/anoxia events, or if they recolonized after. however, in the malo jezero sample # 1, the ratio between quinqueloculinids and elphidiids (0.18 :0.05) is similar to that known from an assemblage found at 1 m depth in experimental conditions in florida (0.35 :0.07 buzas, 1993, p. 159). the different ratio in the veliko jezero sample # 3 (0.02:0.21) probably reflects somewhat different conditions (greater depth, diminished turbulence, no algal cover, lower temperature) which are favorable for elphidiids. the tendency of changing shell shape with depth has been observed as intraspecific variation in operculinas (pecheux, 1995). the morphological changes have been described either as thinning of the walls, or as a change in chamber proportions (hottinger, 1997). in lamellar-perforate foraminifera the thinning of the chamber walls has been shown to be the result of diminishing rates of turbulence in the water column (reiss & hottinger, 1984). the distribution of the morphotypes of e. crispum in the mljet lakes coincides with differences in the nature of substrate. muddy sediments with a high food concentration (samples # 2, 3) host prevalently large, flattened, morphotype # 1, whereas in a sandy substrate (samples # 4, 5) smaller, inflated, morphotype # 2 (with diameters about 40 % smaller than those of morphoshannonequitapercentage of sample wiener bility textulariina miliolina rotaliina index index number % number % number % (h) (e) 1. malo jezero 0.81 0.22 0 0 30 22.73 102 77.27 2. malo more 0.91 0.18 1 0.1 694 71.27 283 28.94 3. veliko jezero 0.97 0.23 1 0.68 12 8.22 133 91.1 4. soline channel 1.12 0.23 0 0 1265 69.89 545 30.11 5. kriæ (open sea) 1.48 0.26 11 1.26 272 31.05 593 67.7 table 6 shannon-wiener index, equitability index, and percentage of textulariina, miliolina and rotaliina, mljet, may 1995. 277vaniëek, juraëiê, bajraktareviê & ∆osoviê: benthic foraminiferal assemblages in a restricted environment... types # 1) prevails. this contrasts jorissen’s (1988) finding from the northern adriatic sea, where large, compact, morphotypes prevail in nutrient-poor conditions, and inflated morphotype in nutrient-rich conditions. on the other hand, this goes along with experimental evidence (ter kuile & erez, 1988) that in lamellar perforate foraminifera the thinning of the chamber walls is a result of thinning of each lamella due to the diminishing rates of turbulence with increase in depth. murray (1991) suggested that elphidiids from a muddy substrate have infaunal preferences, while those from sand are more likely to have an epifaunal preference. langer (1988) and kitazato (1988) have described an epiphytic mode of life for e. crispum specimens, while myers (1943) noted that larger e . c r i s p u m, buried to a depth of about 1 cm, are able to escape in about 1 hour (calculation is made after myers data, where active individuals spend about 12 hours traversing distance of 9 to 12 cm in vertical direction). it is expected that interstitial water in subsurface sediment (at one cm depth) has lower oxygen concentration than water at the water/sediment interface. therefore, thinner, larger specimens (morphotype # 1) prefer muddy sediment with calm water above (table 1; fig. 2). the relative sediment accumulation (relative sedimentation rate) can be estimated by using the percentage of sessile species, because attached species are incompatible with large sediment input (poag et al., 1980). there is a net increase of the percent of specimens of sessile species from malo jezero (absent) toward the open sea (station # 5, kriæ) (fig. 3). it suggests a greater sedimentation rate in the “lakes” than in open waters. the “lakes” most probably act as a trap for terrigenous and authigenous particles due to their topography. haynesina depressula is one of the most abundant species in bottom sediments of both malo jezero and veliko jezero. murray (1991, p. 324), in an ecological overview of foraminifera, has representatives of genus h a y n e s i n a as brackish forams (living in salinity between 0 and 30), although ( ibid, p. 141) some species can survive higher salinity (0-35). at the malo jezero, malo more and veliko jezero stations stained specimens were noticed, indicating that those specimens were most probably authigenic. at the open-sea kriæ station, h. depressula was not recorded, although hydrographic conditions, except for oxygen concentration, are similar to those in the “lakes”. the percentage of h. depressula , similarly to v. bradyana, in the association decreases towards the open sea, whereas at the same time the biodiversity increases. most probably, h. d e p r e s s u l a tolerates stress conditions including a large range of oxygen concentrations, salinity and temperature, but is probably a bad competitor. the lack of h . depressula at the kriæ station might therefore be a consequence of the increased competition there. 6. conclusions this study is based on five surface sediment samples collected in may, 1995, from the mljet lakes, and therefore can be considered only as a preliminary note. however, it is possible to put forward the following conclusions: (1) benthic foraminiferal assemblages from the lakes area and from the nearshore indicate a transition from lagoonal towards open marine conditions, based on the ratio between textulariina, miliolina and rotaliina. (2) the “lakes” behave as temporary hypoxic lagoons, in which the main limiting factor for the benthic foraminifera is oxygen concentration. episodic stagnant conditions in malo and veliko jezero are fig. 3 proportion of sessile specimens of c i b i c i d e s, p l a norbulina , rosalina in investigated samples. 278 geologia croatica 53/2 formed due to large temperature and salinity differences between bottom and surface water, which prevents water mixing. at the same time the “lakes” act as sediment traps with a higher sedimentation rate compared to the adjacent open sea. episodic anoxia is reflected in a low foriminiferal species diversity, high abundance of specimens of two pioneer genera (quinqueloculina a n d e l p h i d i u m), and presence of v a l v u l i n e r i a species tolerant to low oxygen conditions. (3) the number of species and specimens in sediment foraminiferal assemblages increases with the influence of the open sea. in these peculiar marine lakes, unstable ecological conditions do not permit the accommodation of either a large number of species or of specimens, whereas in the nearshore, where ecological conditions are more stable (“normal”), the assemblage is much richer in species. the shannon-wiener index is rather low in all samples suggesting restricted environment (h = 0 .8 -1 . 4 ) , although its value increases continuously from the malo jezero towards the kriæ station. (4) the distribution of morphotypes of e l p h i d i u m c r i s p u m in the mljet lakes may be correlated to substrate type, mode of life, water energy, and oxygen conditions. the larger flattened specimens of morphotype # 1 occur more commonly in a muddy, oxygen depleted, and low energy environment. (5) in the study area, haynesina depressula tolerates a salinity range significantly higher than previously documented. it appears to be well adapted to stressed conditions, but probably cannot tolerate competition. acknowledgments the authors wish to thank the mljet national park authorities for financial support for field research, dr. ivan sondi for help in sampling, miss renata slavkovi∆ (ina naftaplin, zagreb), mr. momir milunovi∆ (ruer boπkoviê institute, zagreb) and mr. miroslav kladni»ki (institute of geology, zagreb) for technical assistance. we also thank to the referees prof. dr. ivan gu©i∆ and dr. franc cimerman for their helpful comments. 7. references b e n o v i ∆ , a. & o n o f r i , v. (1995): ekoloπke osobitosti velikog jezera na otoku mljetu.in: durbe©i∆, p. & benovi∆, a. (eds.): prirodne znaëajke i druπtvena valorizacija otoka mljeta. conf. proc. pomena, otok mljet, september 4-10, 1995, hrvatsko ekoloπko druπtvo, ekoloπke monografije, 6, zagreb, 511-521. benovi∆, a., lu»i∆, d., onofri, v., peharda, m., cari∆, m., jasprica, n. & bobanovi∆»oli∆, s. (2000): ecological characteristics of the mljet island seawater lakes (south adriatic sea) with special reference to their resident populations of medusae.scientia marina (in press). b u l j a n, m. & © p a n, j. (1976): hidrografska svojstva mljetskih jezera i susjednog mora.acta adriatica, 6/12, 1-227. buljan, m. & zore-armanda, m. (1976): oceanographic properties of the adriatic sea.oceanogr. mar. biol. ann. rev., 14, 11-98. b u z a s, m.a. (1979): the measurement of species diversity.in: lipps, j.h., berger, w.h., buzas, m.a., douglas, r.g., & ross, c.a. (eds.): foraminiferal ecology and paleoecology. soc. econ. paleont. mineral., short course, 6, 3-10. b u z a s, m.a. (1993): colonization rate of foraminifera in the indian river, florida.jour. of foram. res., 23/3, 156-161. c a r i ∆, m. & j a s p r i c a, n. (1995): koncentracija hranjivih soli i klorofila α u velikom jezeru u razdoblju stratifikacije.in: durbe©i∆, p. & benovi∆, a. (eds.): prirodne znaëajke i druπtvena valorizacija otoka mljeta. conf. proc. pomena, otok mljet, september 4-10, 1995, hrvatsko ekoloπko druπtvo, ekoloπke monografije, 6, zagreb, 447-451. c i m e r m a n, f., d r o b n e, k. & o g o r e l e c, b. (1988): l’association de foraminiferes benthiques des vases de la baise de veliko jezero sur l’île de mljet et de la falaise lenga, ouverte vers la mér (adriatique moyenne).revue de paléobiologie, vol. spéc. 2 (benthos ′86), 741-753. c i m e r m a n, f. & l a n g e r, m. r. (1991): mediterranean foraminifera.dela sazu iv razreda, 1-95, pls. 1-118, ljubljana. f o l k, r.l. (1954): the distinction between grain size and mineral composition in sedimentary-rock nomenclature.jour. of geology, 62, 344-359. foraminiferi padani (1982): atlante iconografico e distribuzione stratigrafica (terziario e quaternario).sec. edizione, agip s.p.a. milano, 52 pls. h o t t i n g e r, l. (1997): shallow benthic foraminiferal assemblages as signals for depth of their deposition and their limitations.bull. de la soc. geol. de france, 168/4, 491-505. j o r i s s e n, f.j. (1987): the distribution of benthic foraminifera in the adriatic sea.marine micropal., 12/1, 21-48. j o r i s s e n, f.j. (1988): benthic foraminifera from the adriatic sea: principles of phenotypic variation.utrecht micropal. bull., 37, 176. j o r i s s e n, f.j., de stigter, h.c. & w i d m a r k, j.g.v. (1995): a conceptual model explaining ben279vaniëek, juraëiê, bajraktareviê & ∆osoviê: benthic foraminiferal assemblages in a restricted environment... thic foraminiferal microhabitats.marine micropal., 26, 3-15. jura»i∆, m., sondi, i., bari©i∆, d., vdovi∆, n. & pr a v d i ∆, v. (1995): sedimenti i sedimentacija u mljetskim jezerima.in: durbe©i∆, p. & benovi∆, a. (eds.): prirodne znaëajke i druπtvena valorizacija otoka mljeta. conf. proc. pomena, otok mljet, september 4-10, 1995, hrvatsko ekoloπko druπtvo, ekoloπke monografije, 6, zagreb, 107-116. k i t a z a t o, h. (1988): ecology of benthic foraminifera in the tidal zone of a rocky shore.revue de paléobiologie, vol. spec. 2 (benthos ‘86), 815-825. l a n g e r, m. (1988): recent ephiphytic foraminifera from vulcano (mediterranean sea).revue de paléobiologie, vol. spec. 2 (benthos ‘86), 827-832. l o e b l i c h, a.r. & t a p p a n, h. (1987): foraminiferal genera and their classification.van nostrand reinhold, new york , vol. i x+970 p., vol. ii viii+212 p. (pls. 1-847). m u r r a y, j.w. (1973): distribution and ecology of living benthic foraminiferids.heinemann, london, 294 p. m u r r a y, j.w. (1991): ecology and paleoecology of benthic foraminiferes.longman scientific and technical, harlow, essex, 391 p. myers, e.h. (1943): life activities of foraminifera in relation to marine ecology.proc. of the amer. phil. soc., 86/3, 439-457. open university course team (1989): seawater: its composition, properties and behaviour.pergamon press, oxford, 165 p. pecheux, m.j-f. (1995): ecomorpholoy of a recent larger foraminifer operculina ammonoides.g e obios, 28/5, 529-566. poag, c.w., knebel, j.h. & t o d d, r. (1980): distribution of modern benthic foraminifers on the new jersey outer continental shelf.marine micropal., 5/1, 43-69. reiss, z. & hottinger, l. (1984): the gulf of aqaba, ecological micropaleontology.ecological studies 50, springer verlag, berlin, 354 p. s e i b o l d, e. (1958): jahreslagen in sedimenten der mittleren adria.geol. rundschau, 47, 100-117. s e i b o l d, e. & b e r g e r, w.h. (1996): the sea floor. an introduction to marine geology.springer verlag, berlin, 356 p. sen gupta, b.k. & m a c h a i n c a s t i l l o , m . l . (1993): benthic foraminifera in oxygen-poor habitats.marine micropal., 20, 183-201. s o k a », a. & b a j r a k t a r e v i ∆, z. (1995): mikroorganizmi i nanoorganizmi u sedimentima malog i velikog jezera otoka mljeta.in: durbe©i∆, p. & benovi∆, a. (eds.): prirodne znaëajke i druπtvena valorizacija otoka mljeta. conf. proc. pomena, otok mljet, september 4-10, 1995, hrvatsko ekoloπko druπtvo, ekoloπke monografij, 6, zagreb, 125-146. sondi, i., jura»i∆, m., slavkovi∆, r. & pravd i ∆, v. (1995): mineraloπke i povrπinske fizikalno kemijske znaëajke sedimenata mljetskih jezera.in: p. durbe©i∆, p. & benovi∆, a. (eds.): prirodne znaëajke i druπtvena valorizacija otoka mljeta. conf. proc. pomena, otok mljet, september 4-10, 1995, hrvatsko ekoloπko druπtvo, ekoloπke monografije, 6, zagreb, 117-125. straæi»i∆, n. (1979): ljepote i znamenitosti mljetskog jezera.priroda, 1979/5, 144-150, zagreb. ter kuile, b. & erez, j. (1988): the size and function of the internal inorganic carbon pool of the foraminifer amphistegina lobifera.mar. biol., 99, 481-487. vu»eti∆, m. & vu»eti∆, v. (1995): klimatske prilike otoka mljeta kao ëimbenik prilagodbe biljnog svijeta.in: durbe©i∆, p. & benovi∆, a. (eds.): prirodne znaëajke i druπtvena valorizacija otoka mljeta. conf. proc. pomena, otok mljet, september 4-10, 1995, hrvatsko ekoloπko druπtvo, ekoloπke monografije, 6, zagreb, 233-243. vuleti∆, a. (1953): structure géologique du fond du malo jezero et du veliko jezero, sur l’île de mljet.acta adriatica, 6/1, 1-65. manuscript received june 6, 2000. revised manuscript accepted november 13, 2000. 280 geologia croatica 53/2 geol. c roat. 49/2 265·269 3 figs. i tab. zagreb 1996 review paper geothermal energy resources in the republic of croatia overpressured zone ivan mesic, branko kristofek and tamara babic proceedtngs key words: gcolhcnnal resources, overpressure, heat storage. abstract the g reat q uantities of ..; ta red heal , at relati vely shallow depths, enable lis \0 perform two fundamental human activiti es. suitable for :t n indu stri a ll y clean coull try. the first one i<; agriculture throughout the w ho le year and the second one is touri sm with the conside rabl e po\ e nli:ll fo r health resort s . besides the subsurface and slirf<lcc hydropo(cllli al. there j , al so good geothermal energy present , espe­ cially in lhe western and central part o rlhe drava basin. 1. introduction subsurface reservoirs from where the earth's heal is carried upward by sleam or hal water convective c irc ll ­ lati o n a rc c lass ifi cd as hyd rotherm al convectio n sys­ tcms. the exi stence of a hydrothermal resource depends on two basic component s: a heat source, and adequate ve rtical pcrmeability to allow hot fluid s to ri se. 'fhi s type of stored hot wate r is recognized as two systems. the first one is vapor-dominated or hot water, depending on whether steam or liquid water is the dom­ inant press ure-controlling phase in the reservoir. th e second type or this reservoir is hot water. according to the temperature range, hot wate r sys tems a rc divided il1lo three categories: i ) hi gh temperature ran ge ( iso-360°c), suitabl e for e lec tric power generation, 2) inte rmed iate temperat ure range (90 150dc), suitable for space and process heating, j) low temperature sys tem (below 90°c) with li mited usage. although some data do exist in the local literature, no d ata all bas ic geothermal classifi cmion could be found. resource geotherma l e lass i rication follows white & wjlllams ( 1975): tna-nalbplin , subiccva 29 . tirioooo zagreb, croat ia. kljucnc rijcci: geole rmain i izvori , nadt lak, usk ladi ­ slenjc top tine, saietak zel im o ii bili c ista zemlja, s d \' ijc tcmc lj nc tjudske djcla lllos ti , po tjo(ijcistvo rn i turizmo rn . momlllo rabili cistc c l1c rgc(skc izvorc, osim hidropoic ncijala, povrs inskog iii pod zcrnnog . imamo vclikc z;:t­ libe toplinske energij e ii nasclll podzemlju. naroc ilo jc 10 iz razc no ii zapadno iii i srcdisnjctll dij e lll dra\'skog bazena. i . hydrothermal convection resource (heat carried upward by water or steam convection): a) vapor dominated with temperatures around 240°c. b) hot water dominated wi th tempera tures from 350°c to less than 90°c. 2. hot igneous resources (rock intruded in molten form from depth): a) part still molten wi th tempera tures higher than 650°c, b) not molten or so called "hot dry rock" with temperatures from 650 to 90dc. 3. conduction dominated resources (heat carried upward by conduction through rock): a) radiogene tic (heat generat ed by radioac tive decay), with ten1peratures between 30i so°c, b) sedimentary bas ins (hot fluid in sediment a ry rocks) with temperatures be tween 30-1 50°c, c) geopress urcd (hoi /luid under high pressure) with temperatures between iso-200de. prom the economic point of view, three of these sys­ tem s apparently exi st in ou r coun try. t he first one is "ho t d ry rock" wh ich can be spec ified as old rock "in truded" ((ike basement) with temperatures around 170°c, it is assumed that granite, as in the well moir32 (relat ive depth 3100 111 ) is the local source 1'01' this kind of heating. the second is a hoi wate r domi na ted sys­ tems. these systems arc doc limen ted in the literature 266 austria hungary osijek geologia cro:liic:1 49/2 (j ellc, 1987; cubr1c, 1993). the locations ve lika cigiena, lopatincc and olhers can be classified within this sys tem. the third one is the geoprcssllred reservoir recogn ized over the whole area, and which will be dis­ cllssed in more detail. 2. geological setting fig. 1 area o f investigation: shaded areas arc hoi spots which refer 10 the lower part orlhe laic miocene. sed imentary constitue nt s of the west ern and south ­ e rn parts of drava basin (fi g. i ), are sand stones ane! marl s from the miocene period. the middle and earl y miocene arc represented in the western part by sand ­ stones or highstand energy sequences, in the midd le part by carbonates sequences (molve and gola fie lds), while in the eastern part they are represented by sand ­ stones (orcsac) but lowerstand energy seq uences (mes1c, 1995). sedimentary sequences [rom the early f ~ ~ temperature • 'c temperature· 'c o 40 60 80 100 120 140 160 20 40 60 80 100 120 140 160 180 200 ~ ,. •• '~ i ,~ ". 'i '". ,~ ". "'. -i ,,~ ,'i ". ,~ = c= = .. ... 't. ... .. :, . ... ~ ~ " , . . . :. ~ ': ~ ~ 't. ~ " transition zone ... ~ 3 't1l00m ... ~ , , .. ' .. ", " \\ .... :~, -----., , . "", ... ~ ':~ -------:,~ '.' \\ \ :~ :. • , t :". . . " . , '. " . transition lone o overffiessured zone ~ :. ~ ... '. 'skin' u>ldicatklns from the tem'erattile logs on fotjr ii1:~s imotve fieldi ~.:. . '. \ -. • \ .... · , • \ · \ . o o 00 120 ° o expected bed overpressured zone loboul 00%1 ii11h geothermal gradient of abolft 6 qcil oom 000 o 0 0 o 0 o o~ \ proven bed rig. 2 temperature versus depth data are ext rapolatcd form logs alld dst. notc high geothermal g radi en t oj! the top of overpressured zone (over 30°c/looi1l). mcsi(;. kriiitofek & babic: gcothennal energy rc~oll rce.~ in the republic of croatia ... 267 temperature use 200 0 1500 180 refr igeration by ammonia absorption, d igestion in paper pulp 170 heavy water via hydrogeo logy sulfide process , drying of d iatomaceous ea rth 160 dry ing of fis h meal , dryi ng of timber 150"90" 140 food canning 130 extract ion of salts by evaporation and crys tallization 120 fresh water by disti ll ati on 110 drying and c uring of li ght aggregates cement slabs 100 drying of o rganic materi als, seaweed, grass, vegetables, washing and d ry ing of wool 90 20" 90 dry ing of stock fish, intensive de-ic ing o perations 80 space hea ting , greenhouse by space heat ing, anima l husbandry 60 greenhouse by combined space and hotbed hea ting 50 mushroom growing, balneo log ica l baths 40 so il warming 30 swimming pools, biodegradation, fe rmenta ti on 20 fi sh fa rming table i characteristic geothermal systems wide lise (white, 1975). mi ocene, i. e. j6-8 .7 illy, are overpressured. all fl uids in th is region, particulary water, incl uded in sed iments of mesozoic and palaeozoic age, are also overpressured (baric el 'ii. , 1991 ). walel in o lder sed imenl s is mixed wit h hydrothermal sol uti ons and comains other com ponents like h2s, co2 e tc. 'fh is type of water is useless on the surface and has to be used in closed cir­ culation o r heal a lte rat ion. however, this water is a lso interes tin g, for use in sma ll areas of hu man activi ty (e.g. e lectrical power plant). thi s means there is a great volullle or restricted walei' in which a great mass of heat is accumulated , which is shown by the great va lue o f the geothermal gradient (fig. 2). 3. physi cal pr o perties or pot entia l reser voirs overpress ure zones afe re lated to deposition of the regressive sedi ment ary sequences [hal began in the ear­ ly late miocene . t hcse sequences are recogn ized, at the begi nnin g, by the sedi mentary marke r rs7• t his mudstone bed is bot h a sed im entary and stra tig raphic marker ( 11.7 my baric ct ai. , 1992). this sedimen­ tati on event marks the presence o/" regressive sequences in all these areas, with di ffe rent phys ical properti es due to the energy in which they were deposited. examina­ tion of th is bed shows temperatures around 154°c at the top of the overpressure zone, at approx imately 2580 iii depth in the centra l area (molve), at 3500 m in the western area (koprivnicki breg i), and at 3800 m in the eastern area (oresac), as shown in fig. 3. the thickness of these sedimentary sequences, ealled "okoli and iva sandstones" or sediment s between markcrs r s7 (upper badenian, i.e. i j my) and z ' (sarmatian, i.e. 8.7 my), are d ifferent throughout the bas in. in ihe koprivn ick i bregi a rea the thickness is approx imately 1000 tn , whi le in the molve area it decreases to 600 m and in the easte rn part (the oresac area), on ly 300 m is recorded (mesic, 1995). these sandslones sequences are of low poros ity, dependi ng a lso on the ene rgy level a t the beg inn ing of sed iment at ion. the wes tern part , repre­ senting a highstanding energe tic level or de lta plain, i.e. the upper part o f a delt a front , has sedi men ts w ith an average po rosity of around 18%, while the porosity o f the central pan or lower part of the delta front is around j 2%, and the poros ity o f eastern pa rt (o r trans ition bet wcen the lower pa n or the de lta front and to prodelta sed imentat ion), is c lose to 8%. the gas eomposit ion, dissol ved in the water of over­ pressured zone, is in the upper part qui te d ifferent fr0111 that in the lower pan. this can ind icate: 1) influence of the known reservoir and imperfection o/" the cap rock, or 2) the same carrier fl uid in the mai n reservoir and the lower geopress ured zone. t he upper di sso lved gas is dom inanl ly methane (89%) with low co, (0. 5%) . water mineraliza tion is low, around 2.6 gil eg. nne!. the composition o f the lower dissolved gas is simil ar to tha t of the main reservo ir , i. c. methane (7 1 %), co 2 (16%), ii ,s (64 ppm), il g (0.5 mg/m' ), b ui wil h higher water mineral izat ion (4 gil eg. naci). 4. ener g y point of view the amou nt of energy in this volume of sedi mentary sequences can be roughly calculated. although a ll sedi26< geologia cro:l1ica 49/2 pressure gradients· bar 110 m u u u u u u u u u temperature · ·c 40 bo f20 160 200 it--.. l\ f'-r-.. 1\ 1\ 1\ \ 1\ i~ v i / ii \ ----\ --i~ 1\ 1\ j / i ( mcntary masses contain accumulated water, the average cftcc ti vc thickness of 100111, w ith an average porosity o r 8% can result in a imosl 16 klll 3 o r storage capacity. the average temperature we used was 154°c. vw = 16kmj = 16* i09 m3 = 16"' iolldmj cw = 4. 1 r7* i 03 j/oc"'dm j t l = 154°c 12 = 1 j .6°e (average surracc temperature in north croatia) qw = 16* 10 12"'4 .1 87* 10:1*( 154_ 11.6) = 9539"' 10 15 j = 9.54 1'.1 1-> 6"/1 00m 1\ i 3 10 m -"/10 m -----------+ le /10 ' m i fig. 3 progn osi~ of pres­ sure [i nc! geothermal grad ient for lil e a ve r­ age we ll 0 11 lile ta rget area. the complete sto red geothe rmal e ne rgy in these scd imcnlary sequences is close to 9.54 ' 10" j = 9540 i'j = (2.65 • 10" wh = 2.65 mwh). where vw:::: volume of water (dm j), cw:::: caloric value o f 1 elm "' water (jr e .. dm.!), i i :::: temperatu re o f water in reservo ir (oc ), 12 :::: average surface temperature (oc) , and qw = storage of hot water (p j). taking in consideration di sso lv ed gas, the to ta l stored current is even greate r. this stored energy can bc useful on the surface only if great quantities or wate r a rc be in g produced. the iv1csic, kri~lorek & l3allic: geothenlla l energy resources in the republic of croatia . 269 water production depends on the reservoir permeability. the low penneability zone can be avoided by using various attributes of the seismic traces, interval veloci­ ty, gradient and avo (baric et ai., 199 1) permitting us to make several maps and a geological model. this model reduces the chances of incorrect est imation of sedimentary environment, and the position of the zone with sufficient permeability for an economically justifi­ able production rate. 'fhe temperat ure range of conventional power pro­ duction is 180·140"c. 5. conclusion according to world experience, geothermal reso­ urces arc suitable for a wide variety of lises in human act ivities. especially from the ecological point of view, i.1 geopressured reservoir with clean water, the water being clean due to the sedimentary environment, is or great importance to our country. it is shown how important it is to recognize temperature anomalies' vs. depth, not only as the average geothermal gradient. these hot spots, which exist in some parts of the drava basin, especially in the area between koprivnicki bregi and ordae, make thi s area suitable for agriculture, tourism, and other activities that arc uscl'ul , clean, and economically viablc. what is required in thc fu ture are legislative, institutional and environmcntal actions. 6. references baric, g .. mesic. i., jungwirth, m. & span ic, d. (1991): gas·condensate fields in the n·w of the drava dcpression. tn: generation, accumulation & production of europes hydrocarbons. eapg, i , oxford uni versity press, 323-339. baric, g., mesic, 1. & jungwirth, m. (1992): sedimentary and geochemical characteristics or rocks and fluids of the western part of the drava depression.· nana, 43, 225-238, zagreb. cubric, s. (1993): power and energy of geothermal reservoir in the republic of croatia. nafta, 44/7-8, 397-403, zagreb. jelic, k. (1987): stacionarna gcotennijska energija u savskoj i dravskoj potal ini panonskog bazena sr hrvatskc. · nana, 38/6, 333-340, zagreb. mesic, 1. (1995): naftnoplinonosnost kon tinentalnog prcgiba go la-molve-kalinovac.unpublished m.sc. thesis, university of zagreb, 80 p. white, d.e. & williams, d.l. (1975): assesment of geothermal resourccs of united slales.usgs, cire.,726,147 -1 55. white, j.e. (1975): computed se ismic speeds and attenuat ion in rocks with partial gas saturation.­ geophysics, 40, 224-232 . 270 geologia cromiea 49n geol. croat. 1 49/2 127 1 275 1 2 figs. zagreb 1996 review po{)er geological characteristics of the oil fields in the sloven ian part of the pannonian basin pero mioc and miro znidarcic proceedings key words: geological structure, potentia! source rocks, reservoir rocks, structure traps, oil-gas fields. abstract [n (ile slovcnian part of the pannonian basin the oil-gas field pclisovci , the gas fields oolil1<1 and gancani, and lhe oil fields f-ilov­ ei, bakovci and bukovci were discovered. with the exception of pclisoyci, the mentioned fields afc current ly noll prodllclivc. on [his basis, and as a consequence of recent results of oil geo logical investi ­ gat ions, lhe li thostratigraphic description of lhe neogene beds of ihis part of the pannonian basin is presented , together wilh occurrences or source rocks in the given strat igraphic horizons, as well as the struc­ tural charactcristics or thc tcrrilory. the resul ts highlight the some­ what hi ghe r potcntial 01" ccrtain arcas, which is also of importance economicall y. i. introduction the sloven ian part of the pannonian basin is known as ihe mura depression (aksin el ai., 1981). this rep­ resents one of the deep depressions in the marginal area or the southern and southwestern parts of the pannonian basin . the mura depression is bounded in the west by the massifs of the eastern alps, pohorje and kobansko with kozjak, and along the southwestern side by the extensions of the eastern karavanke mountains (fig. i). the eastern extensions of these mountain chains were submerged during the neogene when the basin was formed and in which the neogene beds were deposited . the total area of the slovenian part of the mura depression is approximately 2,640 km 2 • at the end of the 19th century oil was discovered at selnica in the neighbouring croatian part of the mura depression. in the slovenian pan of the depression dur­ ing the second world war two field s were discovered: the peli sovci oil-gas field and the dolina gas field. arter the war, the gas field gancani was discovered , as well as the three oil fields, filovei, bakovci and bukovci (fig. i). in the past , geological and geophysical investiga­ tions over 11 wider region were performed, and a numgeological survey, dimiceva 14, 1000 ljllbljana, slovenia. klj ucnc rijcci: geo[oska struktura, potencijalne mati­ cne stijene, kolektorske stijene, st rukturne zamke, naftno-plinska polja. saietak u slovcnskom dijclu panonskog bazcna ii protck 10m jc razdobljll otkriveno naftno -plinsko polje petisovci, plinska polja dolina i gancani, ic naftna polja filovci , bakovci i bukovci. od spomcnutih nalazista d,lllas je ii proizvodnji samo potje petisovci. na temetjll pri­ je spom cnlltog i s obzirom na rezuttate novijih istrazivanja, prikazan jc litostratigrafski sastav ncogcnskih naslaga ovoga dijcta panonskog bazena, ie pojave maticnih stijena i strllktul'lla gracla podrucja. ii'.nije10 je i misljenje 0 nesto vecoj perspektivnosli istrazivanja na nekim podrucjirna, slo bi bilo i ekonomski naj vaznijc. ber of deep boreholes were drilled. the results of these investigations included the lithological and stratigraphi­ cal study of neogene deposits, determination of the lithological composition of pre-tert iary basement, and tectonic subdivision of the mura depression into indi­ vidual uni ts. in terms of petroleum geology the source rocks were identified from which the hydrocarbons mi grated into favourable reservoir rocks and pools. a number of structural problems were solved, and also the general structures and tectonic units of the known oil and gas fields were determined. this li thostrat igraphical and tectonical framework is presented, together with the petroleum geological char­ acteristics, and the economically optimal areas for future investigations are highlighted. 2. lithostratigraphy the geology of the mura depression can be separat­ ed into three distinct units: the pre-neogene basement, the tertiary sediments (mostly miocene-pliocene), and the quaternary cover. the pre-neogene basement consists of metamorphic rocks and mesozoic sed imentary rocks. among the metamorphics gneisses prevail, with mica schists, <lmphibolites and lenses of eclogite, marble and quartzite (middle austroalpine). these rocks arc over­ lain by phyllites (ordovic ian ) and silurian -devonian 272 \ i \l s p o h 0 r ) dark and greenish schists. these beds were overlain by permo-triassic red sandstones (upper austroalpine). the tri assic is represented by limestones and dolo­ mites, and the youngest mesozoic member is represent­ ee! by senonian limestones, breccias and marl s (plenicar , 1954, 1979; flugel, 1988; mioc el ai., 1993). the tertiary sedimentary rocks consist of neogene beds from ollnangian ponlian age (rijavec, 1976). the oltnangian-carpathian deposit s include conglom­ erate, sandstone and silt itc. in the lower part of these beds individual layers occur (2-10 m lhick) of bilumi­ nous black marl that was identified as the source rock of the hydrocarbons. in the upper part clacitic-andesitic tuff occurs between marls and sandstones. the baden­ ian beds afc represented in their lower part by poorly consolidated coarse grained breccia and conglomerate with sand, overlain by marl and lithothamnian lime­ stone. during the sarmat ian clastic deposi tion contin­ ued, and the marine env ironment became gradually brackish. marls, sands and conglomerates are the char­ acterislic lithological members (rijavec, 1978). this clastic deposition persisted throughout the pannonian and pontian. lilhostratigraphically the neogene beds can be su b­ divided into three formations: the murska sobota for­ mation, from lower miocene to lower pannonian, the lendava formation, from upper pannon ian to lower pontian , and the mura form ation, from dacian to romanian. south of the drava river, in the area of haloze and westerly, in the southern karavanke, older, upper oligocene (egerian) beds also occur in which the anclesitic tuffs of the smrekovec series are especially geologia cromiea 49/2 fig. 1 sketch-map of th e tectonic units of the mura depression. legend: r radgona depression; m murska sobota massif; p ptuj-ljutomer depression; 0ormo7.-seln ica antiform; a-b trace of the profile; supposed borde r between tectonic units; oil-gas fields. characteri sl ic (anicic & jurisa, 1985; mioc, 1978). 3. overview of the geological structure the wider region of the mura depression jies, in the geotectonic sense, in the eas tern extension of lhe east­ ern and southern alps that represent the pre-tertiary basement of this territory. after intensive tangential movements and overthrusts the basement disintegrated into individual blocks (tectonic units) before the miocene. in the areas of subsided units basins formed in which rapid deposition took place. tectonic activ ity of various degrees also continued during deposition of the neogene beds, as evidenced by the variable thi ck­ ness of the neogene sediments. vertical and horizontal movements and weak overthrustings al reverse faults (e.g. the ljutomer fault) are characteristic. in this man­ ner units were form ed in the shape o[ depressions (e.g. the radgona depression) and uplifted blocks horsts (e.g. the murska sobota massif that passes into pohoije in the west). during prospecti ng [or oil and gas, special attention was paid to solving the stratigraphic-tectonic and struc­ tural problems of the wider region. these problems were studied by numerous authors, among them plenicar (1954), simon (1973), kisov ar (1977), mioc & znidarcic (1989), durasek & hari (1992), and olhers. after geophysical investiga­ tion and deep dri ll ing the followin g, more important units were dist inguished from north to south: the rad ­ gona depression, the murska sobota massif, the ptuj mioc & znidareic: geolo~ ic31 char.ic[eristics of [he oil fields in the sloven ian pan of the p:mnonian aasin 273 a ® + @ + ® + 3 5 km 10 2q :xl lj utomer depression and ihe orm oz-sclni ca antiform (figs. 1 and 2). the gcolog ical struc t.ures of the pre-tert iary base­ ment that ex tend in the ne-sw direction are not late ral ­ ly equi va lent , and deposition of the neogene beds did not commence at the same time in all localities. tn the pre-tertiary basement of the radgona depres­ sion older palaeozo ic shales, perm o-triass ic sand­ stone, and limestone with dolomite, as well as creta­ ceous beds occur. thi s basement was overl ain by neo­ gene sediments. their thi ckness inc reases towards the northeast where it exceeds 4,500 m. the ex tension of this unit toward s th e southwest is represent ed by thc ribniea-sclnica grabell (mioc, 1977). the murska sobota massif lies to the south of the radgona dcpress ion. tn the geolog ical structure of ihe pre-tertiary basement gneisses, mica schi sts, amphibo­ lites (cigit, 1958) and evell ec logites were de te r­ mined. t he mass if was tota lly submerged during the badenian aner which the first neogene sediments were deposited ( ill the apical part), and they exceed 2,000 m in thickness. the southwestern extension of this unit is th e pohorj e mass if. th c geologica l stru cture of the wielei' surroundi ngs indicates the poss ibility of erosi onal rcmnant s of carbonate beds (upper triass ic) in the so uthern margin of this un it. t he ptuj-ljut ome r depression li es to the south of the murska sobota mass if and it represent s thc sub­ me rged part of the te rritory between thi s mass if in the north and the ormoz-sclnica antiform in the south. the pre-tertiary basement predominantl y consists o f meta­ morphic rocks, gneisses, amphibolites, and possibly also phyllit es. indiv idual " patches" o f c rus hed to mylonitized dolomite (upper triassic) are preserved on the metamorphics. the thi ckness of the neogenc beds <-ltlains 4,000 iii in the borehole ncar ljutomer. the c rushed dolomit e, approximatcly 40 m thick, beneath these beds, represents a tec tonic remnant of the over­ thrust on gneiss. the pluj -ljutomer tec ton ic unit con­ tinues towards the soulilwest, and its ex tension is prob­ ab ly the mezicavi tanje graben wh ich li es between po holje in the north and 1 orthern karavanke in the south (m ioc ct at., 1993). the onnoz-se lniea antiform is the most southerly or the described units. the northern limit with the ptuj­ ljutomer depression is of tectonic charac tcr, represent­ ed by the ljutomer reverse fault ihat dips to the south. the pre-te rt ia ry basement of the orllloz-seiniea @ b -fig. 2 schematic c ross-section of the territory 40 between th e radgona depres sion and (he onnoz-sclnica antiform. legend : n) neogene (mostl y sand, sa nd stone. marl and clay): t ) triass ic (li mestoncs , do lomi tes 50 a nd dolo mitc brccc ia): ma ) mi (ldl c and upper austroalpine (gnciss. amphibolit e, phylite): -) fault. antiform , as suggested by the reg ional anal ys is of the geo log ica l structure, cons ists of mesozoic , predomi ­ nantl y triassic beds of the northern karavankc. thcse beds arc overthrusted on the metamorphic basement in the nort hern karavanke moun tain s. tn the course o f formin g of the pannoni an bas in these struc tures sub­ sided. the neogene sediments that were deposi ted o n them were deformed already partly during the ir deposi­ tion, and to a larger degrce later, during reactivation of the pre-terti ary basement. this is indicated by reverse faults in the northern rim of the ormoz-seln ica ant iform, and in pan by ovenhrusting on the neighbour­ ing ptuj -ljulomcr depression. the ormoz-selnica antiform is widcst in its north­ west part , and subslanlially narrower towards the south­ east, in the area of the dravinja vineyards and halozc. the major part of this unit , approximately between ptuj and dornava in the sout hwes t, and west o f pe ti sovei and scl niea in thc nol1heast, is somewhat upli fted. fur­ thermore the surface struc ture of the southeast area dips relative ly gently, and only in the south western part, in the area of the dravinja vineyards, are the dip anglcs stec p, ve rtical or even overturn ed. it is important to note that the ormoz-selni ca antiform exi sts at present di sint eg rated into a /lumber o f smallcr anticlinal un its that arc in places sevcral square kilometres in s ize. based on thc geological relat ions in the wider area, the triassic carbonate rocks may be ex pected in the cores of these units. 4. oil geology in the wider region of the sloven ian pan of the mura depression the potentia l source roeks were estab­ lished among the neogcne sediments. favourable reser­ voirs and traps also occ ur together with favourabl e structural conditions. the potential source rocks outcrop in the northeas t­ e rn p<w of the area, in the region of kozjak, and on the southern margin they outc rop in the haloze area. they a re represented by dark bituminous marls to siltites that oeeur in the lower part o f the ollnangian-ca rpathian beds, and appear at several hori zons, varying in thick­ ness at individual levels from a few to more then ten mctres . s imilar marls have also been found in the badenian deposits. these beds extend from the margin s to the cent ral part of the mum depressi on where they 274 were probably the main source or hydrocarbons which migrated into the favourable structures of the reservoir, an cl fo rmed oil-gas fi elds. 5. potential reservoir rocks th e potential reservoirs were found among the rocks of the pre-tertiary basement , as well as in the neogene beds. in the sequence of beds of the pre-te rtiary base­ ment rocks occur that arc bad reservoirs in certain cir­ cumstances, and others with the bes t reservoir proper­ ties . with respect 10 the older tecton ic history and [or­ mati on or th e pre-tertiary basement parts or en ti re unit s o f ihe tectonically deform ed pre-tertia ry base­ ment may be of interest for accumulation of oil and gas , particularly phyllonites (c rushed gneisses), mylonites (crushcd dolomites, limestones, pe rmian-triass ic sand­ stone), breccias (dolomite and limestone) . the phyllonite zone can appea r a long the tectonic contact between phyllonites ove rthrust ing gneisses . in thi s process thc gneisses were crushed into fine fra g­ ments, and they can have bad reservoir propcrt ies. they may be expected in the area of the murska sobota mas­ sif and the footwall of the radgona depression . mylonites, tectonic breccias and fractured carbon­ ates are more favourable as reservoir rocks, particularly the defo rmed triassic dolornites and limestones. the thickness varies from several tens to several hundred metres. they may bc ex pected in the footwall of the radgona depress ion between the neogene beds and the unde rlying metamorphic compl ex . espec ially favo ­ urabl e carbonate reservoirs are expected below the neogene depos its in the area of the onnoz-selnica ant i rorm. these reservoir rocks are part of the fi ssured and deformed northern karavanke carbonate overthrust which consists of triassic, massive and in part layered limes tones, and of upper triassic do lomite. or potential reservoir valuc in the neogene beds are the crushcd breccias, conglomerates and sands tones of ottnangia n-carpathian age. in badenian th e li tho­ thamnian limestone and sandstone that is oftcn fi ssured is al so ravourablc. it a tt ai ns a thickness of several metres to several tens of metres. reservoir horizons can also be found in the sannatian beds (sands tones, con­ glomcrates), as wcll as in thc pannonian and pont ian. the s truc tural traps could bc found in the ottn an ­ gian-carpathian, badenian and pannonian, as well as in polllian depos its. beds of marls, clayey marls and clays occur in individual parts of these stra tigraphic units , and they can form favourable traps. their thickncsses vary from several tens metres to a hundred metres. geologia cm;llica 49(2 structures potentially favourable for oil appear in the region of the ormoz-selnica antiform andlhe radg­ ana depression. in both areas carbonate roc ks tha t arc th e most favourable potential reservoir rocks occur in the pre-tertiary basement. some also appear in neo­ gene beds. the region of the radgona depression disintegrated and individual smaller antiform features were formed. there were poss ibilities for the migration of hydrocar­ bons from the lower parts and their acc umulation in the mentioned structures (e.g. dankovci). in the area of the murska sobota massif sma lle r anticlincs occur in which hydrocarbons accumulated in neogene reservoi r rocks. it is estimated that the o rmoz-selnica unit repre­ sent s the most favourab le area for occurrence of deposits according to its geo logical s truc ture and oil geology c harac teristics. along its strike occur a number of smaller anticlinal s truc tures of several kilometers extension. in the northeas tern part of this unit oil -gas ficlds wcre di scovered in the vicinity of peti sovci, and in the croatian part at sc ln ica, zebanec and the latest gas -fields vukanov ec and vuckovec (runjic et ai. , 1995; seljan & parloy , 1995). in the southweste rn extension of the onnoz-sclnica unit oil and gas were drilled at bukovci, however with­ out any important econom ic results. from the stand ­ point of more recent invest igat ions it was estimated that at bukovei the boreholes were drilled almost parallel to the ve rtica l neogene beds, whcre they did no t find favourable structures (mioc & zn ldarcic. 1989) . 6. conclusions and recommendations in conclusion of this short analysis of geo logical and o il geological informat ion of the mum depress ion, it may be stated : a) the ormoz-selniea st ruct ural unit appears as the most favourable for new petroleum discoveries, b) the next potentially important s tructural unit is the r adgona depression , fo llowed by c) individual areas of the murska sobota massif, in which the possibilities of smalle r occurrences of oil and gas exist, and of even more favourable geot her­ mal water sources. prio r to plann ing further prospccting for petroleum, analysis and interpre tati on of ex is ting data arc neces­ sary. from this , geophysical measurements and further interpretation of the surface structural data are required in order to facilitate a deep dr illing programme. in this manner the location of boreholes will be economically better establi shed. mi oc & zilidarc ;c: geologica i ch~lr;ic1cris ti cs or the oil fields in the slovcnian l'al1 of the pannonian basin 27) 7 . references aksin , y., dragasevic, t. , ku rt, j., mari­ noyic, d. & martinec , r. (1981): tolmao kartc naftnih in plin skih nahajalisc v sfrj 1 :500.000.zvczni gcoloski zavod, beograd, 72 p. anicjc, b. & jur isa, m. (1985): osnovna geoloska karla 1:100.000, '1'01111<1(': za list rogalcc.zvczni gcoloski zavod, beograd, 75 p. cigit, k. (1958): 0 geoloskih razmerah filovske nartnc s trllklurc. gcologija, 4, 171 187, ljubljana. durasek, s. & i-jari, s. (1992): growth faulting and thei r innucncc on hydrocarbon accumulation s at lhc margin or raclgona depression (slovcnia). naf­ ta, 9, 447-462, zagreb . fl uge l, [-i.w. (1988) : steirisches becken -sudbur­ gcn lancii schc schwclle , geologi sche karle des pr~ilcrliaren unt ergruncles.geo logischc bundc­ sans talt , wicn. kisoy ar, m . ( 1977): prilog rjd avanja strukturni h oclnosa naseg d ije la murske depresij c .zbornik radova ill. oeo!. skup znanstv. savjct za naftu hazu, 1, 3 11 -322, zagreb. mioc, p. (1977): geoloska zgradba dravske dol inc ill cd dravogrado1l1 in sclnico.geojogija, 20, 193230, ljubljana. mloc , p. (1978): osnovna geoloska karta i: 100 000, tolmac za list slovcnj gradcc.zvez. geo!. zay., i3eograd, 74 p. mioc, p , an ic [c, b. & znidarcic , m. (1993): pre-tertiary basement characteristics of the western border or pannonian basin in sloycnia. 8th meet­ ling of the association of european geological soc ie ties, abstracts, p. 42, budapest. mioc, p. & znidarcic, m. ( 1989): osnovna geo­ loska kart a 1:100000, toll11ao za l ist maribor in leibnitz. zvezni geol. zay., beograci , 60 p. plenicar, m. (1954): obmurska naftna nahajalisca.­ gcologija, 2, 36-93 , ljubljana. plenicar , m. (1979): podjoga tcrcijarnih s loj cva murske i sjeverozapadnog dijela dravske potoline.­ zbornik radova lv . znanslv. sk., znanstv. savj. za naftu hazu , stubicke toplicc, 45-52, zagreb. rjjayec , l. (1976): biostratigrafija miocena v slove nskih goricah.gcologija, 19, 53-82, ljubl j<lila. rija vee , l. ( 1978): tortollska ill sarlll a tska lllikro­ favna v zahodnelll delu slovenskih goric. gcologi ­ ja , 2 1/2, 209-238, ljubljana. runjlc, s., dragas, m., hundric , y. & kedmenec, a. (1995): nova otkri6a plina i kon­ denzala u murskoj depres iji na lokalitetilll(1 vuekovec i vukanovec. 1. hrv. gcol. kong res , opatija 1995, proceedings, 2, 523-527, zagreb. seljan, d. & parloy, b. (1995 ): struktllrno-tek­ tonski oclnosi na loka1ite tima vuekovec in vukanovec.l hrvatski geol. kongres, opalija 1995, proceedings, 2, 535 -539, zagreb. simon, j. (1973): 0 litostratigrafskom stllpll te rei­ jarnih naslaga u poclrueju istoene slovenije. nafta, 24/3, 119127, zagreb. 276 gcologi;1 croallca 49/2 gc-60-2.indb 1. introduction from the late egerian (early miocene) up to the middle sarmatian (middle miocene) the sedimentary basin of northern and central croatia belonged to the southwestern part of the central paratethys sea (pavelić et al., 1998). sedimentation in paratethys is known for its peculiar palaeoenvironmental characteristics, due to temporary connections and disconnections with the mediterranean (tethyan) realm (rögl, 1998). in the late badenian (fig. 1) the seaway from the mediterranean to central paratethys in slovenia was closed. however, the eastern anatolian seaway had opened again as shown by the presence of indo–pacific microfossil assemblages in central paratethys (rögl, 1999). all over paratethys a final marine transgression covered all the different facies. the geological composition of medvednica mt., n of zagreb, together with the surrounding cenozoic basin sediments, has been subject to numerous geological and palaeontological studies (gorjanovićkramberger, 1908; šikić et al., 1979; avanić, palaeoecology of the late badenian foraminifera and ostracoda from the sw central paratethys (medvednica mt., croatia) đurđica pezelj¹, jasenka sremac¹ and ana sokač2 1997; kovačić, 2004). a detailed description of the miocene deposits from the southern and south-western slopes of medvednica mt., and a detailed list of late badenian macrofossils is given by kochanskydevidé (1944, 1957). šikić (1967, 1968) proposed a biostratigraphic zonation of badenian and sarmatian deposits on the basis of foraminiferal communities. bajraktarević (1984) described the fossil microfauna and nannoflora of the marly middle miocene deposits in detail (badenian and sarmatian). badenian ostracods from medvednica mt. were determined by hajek-tadesse (2006). more detailed studies of microfossils from north-western croatia can be found in the unpublished reports of the croatian geological survey. up-to-date research of the late badenian sediments from the medvednica mt. has mostly been restricted to taxonomic determination of fossils and descriptions of lithological types. palaeoecological studies with detailed statistical analyses are notably absent. therefore the main scope of this paper is a detailed palaeoecological interpretation of the late badenian depositional environments at the sveta barbara locality (fig. 2), based on quantitative data analysis of the foraminifera and ostracods. the authors hope that their efforts will contribute to the general reconstruction of the late badenian sedimentary basins in the wider area of the southern pannonian basin system. 2. geological setting medvednica is an approximately 40 km long mountain in northern croatia, striking from the south-west towards the north-east. its core is composed of precenozoic rocks, surrounded by neogene (miocene, pliocene and pleistocene) deposits (šikić, 1995). badenian deposits represent the most prominent part of the cenozoic complex of medvednica mt. they transgressively overlie the lacustrine to marine lower miocene deposit cover and the palaeocene to pre-cenozoic basement rocks forming a palaeo-island on the southwestern margin of the pannonian basin system. these deposits are known for the high diversity of facies and early, middle and late badenian ages can be clearly geologia croatica 60/2 139–150 4 figs. 4 tabs. zagreb 2007 key words: benthic foraminifera, ostracoda, palaeoecology, biostratigraphy, late badenian, medvednica mt., croatia. 1 department of geology and palaeontology, faculty of science, university of zagreb, horvatovac 22a, hr-10000 zagreb, croatia; e-mail: durpezelj@yahoo.com ² faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, hr-10000 zagreb, croatia; e-mail: ana.sokac@zg.htnet.hr abstract the quantitative study of microfossil communities from the late badenian marls at the sveta barbara locality (eastern medvednica mt.) enabled reconstruction of three different palaeoenvironments: middle shelf, outer shelf and upper bathyal. the dominant factors influencing the distribution of biota were the deepening of the depositional basin and fluctuations of the oxygenation rate. the outer shelf biota existed under conditions of decreased oxygen levels in bottom water, compared to communities from the middle shelf and upper bathyal environments. 140 geologia croatica 60/2 distinguished due to the index microfossil distribution. this enables accurate correlation with the standard central paratethys ecostratigraphic benthic foraminiferal zonation (papp et al., 1978; basch, 1983). during the early badenian planktonic taxa dominated the microfossil communities (šikić, 1995). these badenian deposits belong to the lagenidae zone, divided into 2 subzones on the basis of the uvigerinids. the middle badenian can be recognized through the domination of agglutinated foraminifera (‘sandschaler zone’), containing the abundant specimens of spiroplectinella carinata d’orbigny. late badenian sediments reflect the maximum of the marine transgression and basinal deepening, respectively, onlapping in most cases pre-cenozoic basement rocks (lučić et al., 2001). their lower part, the bulimina–bolivina zone, contains numerous small benthic foraminiferal taxa, while the uppermost badenian (‘barren zone’, ‘rotalia zone’) can be recognized by the impoverishment of the fauna. the genus elphidium dominates, together with the ammonia beccarii (linné) and the genus quinqueloculina. the sveta barbara section is located west of the sesvete–čučerje road, in the lipa creek trench, near pukleki village (fig. 2). the outcrop is approximately 9 m thick (fig. 3). the lower part of the section is represented by weathered laminated marls, which are light brown in colour (samples s1, s2). in the upper part of that unit, three lens-shaped intercalations of a grey, massive marl (sample s3) can be observed. these lenses are 30–50 cm thick, irregularly embedded within the light brown marl. in the central part of the section, brownishgrey clay-rich marls prevail (samples s4, s5 and s6), while the uppermost part of the section is composed of greyish clay (samples s7 and s8). samples were taken at intervals of 1 m. 3. materials and methods approximately 300 g of the sediment per sample was dried, treated with hydrogen peroxide and washed through 0.5, 0.25, 0.125 and 0.063 mm sieves. fractions >0.63 mm were chosen for analysis. all standard samples were obtained by the multiple “splitting” of the sample into equal parts, and about 300 specimens of foraminifera were extracted. as ostracods, unlike foraminifera, are scarce in the samples, they were hand picked from 1 g of the dried residue (>0.63 mm). statistical analysis qualitative and quantitative analysis of the foraminifera and ostracod communities were the next steps in the taphofacies analysis. (1) the determination of the collected foraminifera genera and species was performed according to papp et al. (1978), papp & schmid (1985), cicha et al. (1998), and baldi (1999), while the higher taxonomic categories were taken from loeblich & tappan (1988a, b). for the analyzed samples the following quantitative data were calculated: – planktonic/benthic ratio (p/b) – percentage of the planktonic foraminifera in foraminifera community was calculated on the basis of 300–350 specimens, fig. 1 location of medvednica mt. in central paratethys during the late badenian (after rögl, 1999 – modified). 141pezelj, sremac & sokač: palaeoecology of the late badenian foraminifera and ostracoda... using the formula p/b = p/(p+b) x 100%. interpretation of the obtained data was done according to murray (1991), with divisions into inner shelf (<20% planktonic tests), middle shelf (20–50%), outer shelf (50–70%) and upper bathyal zones (>70% planktonic tests). – number of benthic foraminifera (bfn) – number of specimens of benthic foraminifera in 1 g of sediment was calculated. – number of species of benthic foraminifera (s). – relative abundance of benthic species within the community was estimated according to murray (1991): dominant species (>10%); common species (4–10%); accessory species (1–4%); rare or accidental species (<1%). – species diversity of benthic foraminifera was estimated by the shannon–wiener index (h), dominance (d) and fisher α index (α). – benthic foraminifera were classified according to the wall structure: agglutinated, porcellaneous, hyaline. – in order to determine the quantity of oxygen in the bottom water, the classification proposed by kaiho (1994) was applied. oxic indicators (>1.5 ml/l); suboxic indicators (0.3–1.5 ml/l) and disoxic indicators (0.1–0.3 ml/l) can be distinguished. benthic foraminiferal oxygen index (bfoi) – index for quantity of dissolved oxygen was calculated for benthic foraminifera (kaiho 1994; 1999), and the infauna/epifauna ratio was estimated. palaeoecological interpretations of the studied species were done after murray (1991), jorissen et al. (1995), den dulk et al. (2000) and duijnstee et al. (2004). fig. 2 detail of the topographic map of medvednica mt. and location of the investigated sveta barbara profile. fig. 3 simplified lithological column at sveta barbara locality. 142 geologia croatica 60/2 these results were combined with quantitative and qualitative analysis of the ostracoda communities. (2) ostracoda were determined according to huber-mahdi (1984), brestenska & jiříček (1978), yassini (1978) and hajek-tadesse (2006), while higher taxonomical categories were taken from van morkhoven (1962, 1963). the following features were taken into consideration: – ostracod number (on) – number of ostracods valves in 1 g of dry sediment. whole carpaces were calculated as two valves (danielopol et al., 2002). – number of species and their relative abundance within the community. the same classification was applied as that used for the foraminifera. – carpace/valve ratio was calculated. 4. results the microfossil community at the sveta barbara locality is, in general, well preserved, diverse in species and extremely rich in the number of foraminiferal specimens in most samples. numerous ostracod specimens were observed in samples s7 and s8. sample s3 did not contain ostracoda and planktonic foraminifera, and benthic foraminifera are scarce and poorly preserved; therefore this sample was not included in the statistical analysis. all together, 36 genera with 49 species of benthic foraminifera were determined: 4 species from the suborder textulariina, 1 species from suborder miliolina, 12 species from the suborder lageniina and 32 species from the suborder rotaliina (table 1). planktonic foraminifera are represented by 4 genera and 9 species (globigerina regularis d’orbigny, g. bulloides d’orbigny, g. obesa (bolli), globigerinoides trilobus reuss, orbulina universa d’orbigny, o. suturalis brönniman, globorotalia cf. mayeri cushman & ellisor, globigerina sp., globigerinoides sp.). furthermore, 18 genera with 21 species of ostracoda from the suborder podocopina were recognized (table 2). figure 4 shows the graphic trends of the planktonic/benthic ratio and the benthic foraminiferal oxygen index. mean values of these indices, including species diversity (fisher α index, shannon–wiener index and dominance), benthic foraminifera number, number of species of benthic foraminifera and ostracods, ostracod number, dissolved oxygen indicators, infauna/epifauna ratio and wall composition from the resulting different badenian environments are shown in table 3. along the profile, the percentage of planktonic foraminifera increases, thus indicating the deepening of the depositional basin. values of the planktonic/benthic ratio (fig. 4, table 3), indicate that the microfossil communities from samples s1 and s2 (average 44.81% planktonic tests), probably lived on the middle shelf, at depths of 100–150 m. communities from samples s4, s5 and s6 (average 61.59% plankton) lived slightly deeper, probably at the outer shelf, between 150–200 m. the plankton content in samples s7 and s8 (average 83.31%) is typical for the upper bathyal zone (200– 600 m). high oxic conditions (bfoi=50–100) are typical for middle shelf environments, while moderate oxic conditions (bfoi=15–50) prevail in the upper bathyal environment, and low oxic conditions (bfoi 0–15) are recorded in the outer shelf environment (fig. 4). the highest value of the fisher α index (α=16.210) and the greatest number of species of benthic foraminifera (s=49) is recorded in the middle shelf environment, while a less diverse assemblage is observed in the outer shelf environment (α=3.624; s=16). the shannon–wiener index ranges between 1.902–3.147, with the highest values in the middle shelf environment. dominance ranges between 0.06161–0.28860, with the highest values in the outer shelf environment. the greatest number of benthic foraminifera in 1 g of the sediment is recorded in the outer shelf environment (bfn=7452/g), while ostracods are the most abundant in the upper bathyal environment (on=490/g). most of the determined benthic foraminifera are typical for shelf and upper bathyal environments. it is interesting that in the outer shelf and upper bathyal environments shallow-water taxa (elphidium, asterigerinata, neoconorbina, cibicides) only occur in the finest fraction. they are poorly preserved, with abraded tests. it is most likely that they were postmortally transported to deeper environments, and therefore were not statistically analyzed. unlike foraminifera, ostracods from the middle and upper shelf samples are well preserved, but extremely scarce. therefore statistical analysis of abundance could not be performed. in the upper bathyal environment, a significant increase in the number of ostracod valves was observed (more than 32x), and 16 new species appear (tables 2, 3). a list of species of benthic foraminifera and ostracods with a relative abundance greater than 5% in at least one sample are shown in table 4. biostratigraphic position the biostratigraphy of the studied section is based on the standard zonations for paratethys (papp et al., 1978; papp & schmid, 1985; cicha et al., 1998). within the benthic foraminiferal community, dominant taxa are bulimina, bolivina and small globigerinids, thus indicating the bulimina–bolivina zone of the late badenian. further evidence of this correlation is the presence of important species, e.g. p. neudorfensis toula and u. bellicostata luczkowska, which are indicative of the late badenian of central paratethys (papp et al., 1978). 143pezelj, sremac & sokač: palaeoecology of the late badenian foraminifera and ostracoda... species / samples oxic mode s1 s2 s3* s4 s5 s6 s7 s8 preference of life suborder: textulariina delage & herouard martinottiella communis (d´orbigny) o e 2 3 0 0 0 0 1 1 textularia gramen d´orbigny o e 1 1 0 1 1 1 3 5 textularia laevigata d´orbigny o e 1 2 0 0 0 0 2 0 textularia mariae d´orbigny o e 3 5 0 0 0 0 0 0 suborder: milioliina delage &herouard sigmoilinita tenuis (czjzek) o e 7 9 0 2 2 0 5 5 suborder: lageniina delage &herouard laevidentalina elegans d´orbigny s i 1 0 0 0 0 0 2 4 nodosaria guttifera (d´orbigny) s i 1 0 0 0 0 0 1 0 nodosaria sp. s i 1 0 0 0 0 0 0 0 pseudonodosaria brevis d´orbigny s i 1 0 0 0 0 0 1 0 lenticulina gibba (d´orbigny) s e 3 0 0 0 0 0 0 0 lenticulina inornata (d´orbigny) s e 2 2 2 1 0 0 3 3 lagena striata (d´orbigny) s i 1 0 0 0 0 0 0 0 lagena sp. s i 2 0 0 0 0 0 0 0 guttulina communis d´orbigny s i 4 0 0 0 0 0 1 3 glandulina ovula d´orbigny s i 2 0 1 0 0 0 0 0 fissurina sp. s i 1 0 0 0 0 0 2 2 hoeglundina elegans (d´orbigny) s e 1 0 0 0 0 0 1 1 suborder: rotaliina delage &herouard bolivina antiqua d´orbigny d i 1 0 0 4 0 0 5 3 bolivina dilatata reuss d i 25 19 1 54 86 153 37 47 bolivina pseudoplicata heron-allen & earlan d i 2 3 0 1 0 0 10 6 cassidulina laevigata d´orbigny s i 37 47 0 26 17 21 2 2 globocassidulina oblonga (reuss) o i 31 33 0 9 4 17 13 23 bulimina elongata d´orbigny s i 23 30 6 33 12 10 3 16 bulimina insignis luczkowska s i 1 1 0 12 11 5 0 0 globobulimina pyrula (d´orbigny) d i 7 4 0 23 14 8 7 4 pappina neudorfensis toula s i 3 1 0 4 5 0 1 0 uvigerina brunnensis karrer s i 2 1 0 3 0 0 2 0 uvigerina bellicostata luczkowska s i 6 7 0 3 5 3 12 1 uvigerina semiornata d´orbigny s i 19 14 0 52 57 13 40 56 uvigerina venusta franzenau s i 21 6 0 27 8 15 42 24 fursenkoina acuta (d´orbigny) s i 15 12 0 2 4 3 1 2 eponides repandus (fichtell & moll) o e 1 8 0 0 0 0 3 2 sphaeroidina bulloides d´orbigny s i 3 1 0 0 0 0 3 1 neoconorbina sp. o e 1 1 0 0 0 0 1 0 cibicidoides pseudoungerianus (d´orbigny) o e 30 41 0 3 8 17 20 29 cibicidoides sp. o e 1 6 0 1 0 0 6 4 planulina austriaca (d´orbigny) o e 4 3 0 0 0 0 11 6 cibicides boueanus d´orbigny o e 1 2 0 4 0 0 2 0 cibicides lobatulus (walker & jacob) o e 1 0 0 3 1 3 1 2 asterigerinata planorbis (d´orbigny) o e 2 5 0 0 0 0 1 1 nonion commune (d´orbigny) s i 13 14 2 6 14 11 6 4 melonis pompilioides (fichtell & moll) s i 17 9 0 21 6 9 19 23 pullenia bulloides (d´orbigny) s i 1 1 0 1 5 2 3 3 allomorphina trigona reuss s i 2 1 0 1 0 0 1 0 chilostomella ovoidea reuss d i 8 3 2 31 44 6 6 4 oridorsalis umbonatus (reuss) s e 1 0 0 0 0 0 4 3 heterolepa dutemplei d´orbigny s e 1 3 0 2 0 0 5 2 hansenisca soldanii d´orbigny s e 2 10 0 2 3 0 6 6 elphidium sp. o e 1 2 0 1 4 4 2 2 317 310 14 333 311 303 297 300 table 1 list of identified benthic foraminifera species with their oxic preferences, modes of life and absolute abundance for each standardized sample (o – oxic, s – suboxic, d – disoxic, i – infauna, e – epifauna). 144 geologia croatica 60/2 samples from the sveta barbara locality contain vast quantities of planktonic foraminifera, but the important index species, particularly of the genus globorotalia are missing. other species of the genera orbulina and globigerina, which have wider stratigraphic ranges are more abundant. among the ostracods, the badenian species cnestocythere lamellicostata triebel and aurila haueri (reuss) are the most important (brestenska & jiříček, 1978; riha, 1989; jiříček & riha, 1991). 5. discussion recent research has shown that foraminifera and ostracods provide an excellent source of palaeoecological/ecological data (murray, 1991; mazzini et al., 1999; elewa, 2004). this is partly due to their abundance, wide geographic distribution and the variety of environments where they can be found. it is a known fact that their distribution depends on the interaction of a large number of abiotic and biotic ecological factors. therefore, through detailed analyses species / samples s1 s2 s4 s5 s6 s7 s8 c v c v c v c v c v c v c v suborder: podocopina sars bairdoppilata sp. 0 0 0 0 0 0 0 0 0 0 0 3 0 0 argilloecia cf. acuminata müller 0 0 0 0 1 0 0 2 0 0 62 14 48 32 paracypris sp. 0 0 0 0 0 0 0 1 0 0 0 43 2 19 callistocythere canaliculata (reuss) 0 0 0 0 0 0 1 7 0 0 0 3 0 2 cnestocythere lamellicosta triebel 0 0 0 0 0 0 0 0 0 0 2 0 0 0 aurila haueri (reuss) 0 4 0 2 1 0 0 1 0 0 0 19 0 5 urocythereis sp. 0 0 0 0 0 0 0 0 0 0 0 2 0 1 henryhowella asperrima (reuss) 0 0 0 1 0 0 0 0 0 0 1 17 1 34 olimfalunia sp. 0 1 0 0 0 0 0 0 0 0 0 2 0 0 krithe papillosa (bosquet) 0 0 0 0 0 0 0 0 0 0 8 19 10 8 parakrithe dactylomorpha ruggieri 0 0 0 0 1 3 0 1 0 0 25 34 18 21 semicytherura cf. alifera (ruggieri) 0 0 0 0 0 0 0 0 0 0 1 13 1 4 cytheropteron cf. alatum sars 0 0 0 0 0 0 2 5 2 0 2 9 3 12 eucytherura sp. 0 0 0 0 0 0 0 2 0 0 0 23 1 20 semicytherura sp. 0 0 0 0 0 0 0 0 0 0 0 3 0 1 loxocorniculum hastatum (reuss) 0 0 0 0 0 0 0 0 0 0 0 14 0 0 loxoconcha punctatella (reuss) 0 0 0 4 0 0 0 0 0 0 0 11 1 2 loxoconcha cf. parallela müller 0 0 0 0 0 0 0 0 0 0 0 13 0 0 paracytherois sp. 0 0 0 0 2 0 0 3 0 0 11 3 6 1 xestoleberis margaritea (brady) 0 3 1 5 0 1 0 0 0 0 1 11 1 6 xestoleberis cf. glabrescens (brady) 0 0 0 1 1 0 4 2 0 0 0 8 0 1 0 8 1 13 6 4 7 24 2 0 113 264 92 169 table 2 lis fig. 4 graphical trends of the planktonic/benthic ratio and benthic foraminiferal oxygen index. 145pezelj, sremac & sokač: palaeoecology of the late badenian foraminifera and ostracoda... of foraminiferal and ostracod palaeocommunities, we can obtain data on the depth, temperature, salinity, amount of oxygen and quality of substrate in their palaeoenvironments (bonaduce et al., 1975; van harten, 1986; murray, 2001; de deckker, 2002; smith & horne, 2002). 5.1. benthic foraminifera in the analyzed samples, deep-water taxa of benthic foraminifera are present, but significant differences can be observed in the number of species and the variation in dominant and common species. current research has shown that these differences in most cases reflect the changes in palaeobathymetry, or ecological stress, which is usually linked to shifts in the palaeoproductivity of ancient oceans and seas – changes in nutrient supply and quantity of oxygen in the bottom water (den dulk et al., 2000). jorissen et al. (1995) emphasize the important role that oxygen in pore water within the sediment has on the distribution of foraminifera in shelf and continental slope environments. it can be expected that the quality of the available diet (composition of nutrients) will change with decreased oxygen in the bottom water, which can be fatal for foraminifera with specialized feeding habits. in contrast, species tolerant of the lack of oxygen (opportunistic taxa), could benefit from the food supply, and become more abundant (van der zwaan et al., 1999; murray, 2001). 5.1.1. middle shelf environment middle shelf environment is characterized by the maximum number of species, and significant numbers of specimens of benthic foraminifera in 1 g of sediment (table 3). values of shannon–wiener index and fisher α index indicate a normal marine environment with high species diversity, while a rather low value of dominance indicates the poorly expressed domination. dominant species are cassidulina laevigata, cibicidoides pseudoungerianus and globocassidulina oblonga. c. laevigata is typical for the inner–middle shelf environments (loubere, 1996; mendes et al., 2004). researching the distribution and microniches of benthic foraminifera on the southern adriatic shelf de stigter et al. (1998), noticed that c. laevigata abruptly decreases in number with increasing depth and decreasing food supply. the species c. pseudoungerianus and g. oblonga do not tolerate environmental stress, particularly reduced oxygen levels in bottom water (jorissen, 1999). this community is characterized by the significant number of oxic indicators, such as g. oblonga and c. pseudoungerianus and suboxic indicators: c. laevigata, bulimina elongata, fursenkoina acuta, uvigerina semiornata, nonion commune, uvigerina venusta and melonis pompilioides. disoxic indicators are less abundant (most common is bolivina dilatata). the high percentage of oxic indicators and epifaunal taxa within the community, as well as the high value of middle shelf (s1–2) outer shelf (s4–6) upper bathyal (s7–8) range average range average range average foraminifera p/b ratio (%) 41.47–48.15 44.81 55.08–68.09 61.59 81.40–85.21 83.31 number of species 35–49 42 16–26 21 31–37 34 *bfn 3124–3751 3438 5002–7452 6227 1586–2004 1795 fisher α index 10.140–16.210 13.175 3.624–6.651 5.138 8.735–11.260 9.998 shannon-wiener index 2.936–3.147 3.042 1.902–2.586 2.244 2.743–2.982 2.863 dominance 0.06161–0.07657 0.06909 0.09834–0.28860 0.19347 0.07603–0.09633 0.08618 bfoi 65.04–78.68 71.86 8.86–16.92 12.89 47.15–51.88 49.52 oxic indicators (%) 25.24–34.52 29.87 4.58–11.49 8.04 20.00–23.39 21.69 suboxic indicators (%) 56.13–61.20 58.67 32.09–60.61 46.36 54.92–57.59 56.26 dysoxic indicators (%) 9.35–13.56 11.46 34.77–56.42 45.60 21.69–22.41 22.05 infauna (%) 66.77–79.18 72.98 93.92–96.31 95.12 75.86–77.29 76.58 epifauna (%) 20.82–33.23 27.02 3.69–6.08 4.88 22.71–24.14 23.42 aglutinated (%) 2.22–3.54 2.88 0.30–0.33 0.32 2.00–2.02 2.01 porcellanous (%) 2.20–2.91 2.56 0–0.64 0.32 1.67–1.68 1.68 calcareouos (%) 93.55–95.58 94.56 99.05–99.67 99.36 96.30–96.33 96.31 ostracoda number of species 3–5 4 1–9 5 16–21 19 *ostracod number 8–15 12 4–38 21 353–490 422 *specimens p.g. table 3 mean values of planktonic/benthic ratio and different palaeoecological indicators of benthic foraminifera and ostracoda from various late badenian environments. 146 geologia croatica 60/2 bfoi (high oxic environment) indicate that the microfossil community of the middle shelf lived in a normally oxygenated environment, with plenty of food. 5.1.2. outer shelf environment compared to the previous community, number of specimens in the samples from the outer shelf increases by almost 100%, while the number of species decreases (table 3). additionally, lower values of the diversity indicators, such as shannon–wiener index and fisher α index, as well as the increase of domination indicate environmental changes and more stressful conditions. typical species of middle shelf benthic foraminifera decrease in number, and the fauna is dominated by the species b. dilatata, u. semiornata, nonion commune and chilostomella ovoidea, which represent more than 54% of the entire benthic community. this community consists of semi-equal numbers of suboxic indicators (u. semiornata, n. commune, u. venusta, c. laevigata) and disoxic indicators (b. dilatata, c. ovoidea and globobulimina pyrula). oxic indicators are present in minor quantities. the predominance of suboxic and disoxic indicators indicate lower values of the oxygen content, compared to the middle shelf community. the presence of b. dilatata is significant as it is generally connected with poorly oxygenated environments (bernhard, 1986; sen gupta & machain-castillo, 1993). some genera, including globobulimina and chilostomella are typical for low oxygen environments. they are common in the surface sediments of recent poorly oxygenated basins (sen gupta & machain-castillo, 1993), but they can also live several centimeters deep in oxygen poor subsurface sediments in open ocean environments (de stigter et al., 1998; jorissen, 1999). oxygen depletion can be confirmed through a low value of bfoi (low oxic environment) and a decrease in the number of epifaunal biota within the benthic foraminiferal community, as well as lower species diversity, higher domination, and a reduced number of taxa. furthermore, in this sample, the percentage of porcellaneous foraminifera is lower, and it is generally known that miliolids are sensitive oxygen indicators, being scarce, or completely absent in poorly oxygenated deepwater environments (duijnstee et al., 2004). it is evident that in the open shelf badenian environment at the sveta barbara locality, the amount of oxygen in the bottom water was decreased. the large number of specimens in the sediment can be explained by fast reproduction, due to the high amount of nutrients. it is generally known that the biomass, as well as the abundance of foraminifera, depends on the food supply. at the same time, the benthic biota must adapt to disoxic conditions, which are often a consequence of a large quantity of organic matter. oxygen content in pore waters becomes the limiting ecological factor in such environments, and foraminiferal communities are mostly composed of taxa tolerant to disoxic conditions (den dulk et al., 2000). species / samples s1 s2 s4 s5 s6 s7 s8 foraminifera bolivina dilatata 7.87 6.13 16.22 27.65 50.49 12.46 15.67 chilostomella ovoidea 2.52 0.97 9.31 14.15 1.98 2.02 1.33 globobulimina pyrula 2.20 1.29 6.91 4.50 2.64 2.36 1.33 uvigerina venusta 4.73 1.94 8.11 2.57 4.95 14.14 8.00 uvigerina semiornata 5.98 4.51 15.62 18.33 4.29 13.46 18.67 uvigerina costatoides 1.89 2.26 0.90 1.61 1.65 4.04 5.33 bulimina elongata 7.24 9.68 1.80 3.86 3.30 1.01 0.33 fursenkoina acuta 6.62 3.87 0.60 1.29 0.99 0.34 0.67 melonis pompilioides 4.10 2.91 6.31 1.93 2.97 6.40 7.67 nonion commune 5.36 4.51 9.91 4.50 3.63 2.02 1.33 cassidulina laevigata 11.66 15.17 7.81 5.47 6.94 0.67 0.67 globocassidulina oblonga 9.78 10.66 2.70 1.29 5.61 4.38 7.67 cibicidoides pseudoungerianus 9.46 13.23 0.90 2.57 5.61 6.73 9.66 ostracoda argilloecia cf. acuminata 28.16 36.26 parakrithe dactylomorpha 17.14 16.15 henryhowella asperrima 3.88 10.20 paracypris sp. 8.78 6.52 krithe papillosa 7.14 7.93 eucytherura sp. 4.69 6.23 table 4 list of benthic foraminifera and ostracod species with a relative abundance greater than 5% in at least one sample. 147pezelj, sremac & sokač: palaeoecology of the late badenian foraminifera and ostracoda... 5.1.3. upper bathyal environment in the upper bathyal environment, the number of specimens evidently decreases, but, at the same time, the number of species increases (table 3). dominant species are u. venusta, u. semiornata and b. dilatata. suboxic indicators are the dominant species in this community (u. venusta, u. semiornata, melonis pompilioides). oxic indicators (c. psudoungerianus and g. oblonga) and disoxic indicators (b. dilatata) are present in similar quantities. a decrease in the typical disoxic indicators, followed by an increase in the oxic indicators, compared to the outer shelf community, indicates the increase of the oxygen content in this environment. this can be confirmed through the value of bfoi (moderate oxic environment), and the increase in the number of epifaunal biota within the community. diversity is increased, domination is low, and there is a rise in the number of porcellaneous foraminifera within the community. therefore, the upper bathyal community lived in a deeper, but better oxygenated environment, than the community from the outer shelf. during the palaeoecological reconstruction of the sveta barbara profile, sample s3 should also be taken into consideration. this sample was taken from the lense of grey massive marl in the central part of the profile. in this sample only 14 specimens of poorly preserved and probably transported benthic foraminifera were found in 1 g of sediment. considering the lithological data, these lenses could be blocks of older sediment transported from the palaeoshore or a submarine slide. 5.2. planktonic foraminifera the planktonic foraminiferal community is marked by a large number of specimens, but rather small number of taxa. the dominant species are globigerina bulloides d’orbigny, globigerina obesa (bolli) and orbulina universa d’orbigny. globigerina regularis d’orbigny, globigerinoides trilobus reuss, orbulina suturalis brönniman, globigerina sp. and globigerinoides sp. are also present. in samples from the upper shelf tests are smaller, but completely developed, thus indicating the more stressed ecological conditions in this environment. 5.3. ostracoda at the sveta barbara locality, a typical deep-water ostracod community was collected. in deep-water environments the dominant genera have thin, porous valves, with smooth surfaces. hinges are in most cases weak, seldom with teeth, and these ostracods have no eyes (peypouquet, 1983; dall’antonia et al., 2003). different species of the genera krithe, parakrithe, argilloecia and paracypris are very common, and several taxa with more ornamented valves are also present, belonging to genera such as eucytherura and henryhowella. in the middle shelf samples several specimens of aurila haueri, xestoleberis margaritea and olimfalunia sp., and in the outer shelf, a few specimens of paracytherois sp., parakrithe dactylomorpha, argilloecia cf. acuminata, xestoleberis cf. glabrescens and aurila haueri occur. the dominant species in the upper bathyal environment (table 4) are argilloecia cf. acuminata, parakrithe dactylomorpha and henryhowella asperrima. common species include paracypris sp., krithe papillosa, paracytherois sp. and eucytherura sp. the genera argilloecia, krithe, parakrithe, paracypris and paracytherois are typical representatives of deep-water ostracoda faunas, in most cases appearing below 100 m depth, while the genus eucytherura usually lives below 50 m, but has been also found at depths over 1000 m (szcechura, 1994). argilloecia acuminata has a maximum abundance below 170 m in the adriatic sea (bonaduce et al., 1975; ciampo, 2003). although the recognition of transported valves is not easy, allochtonous specimens, originating from shallow water environments, can be clearly separated from the autochthonous ostracod community. bottom streams can be an important mode of transportation. post-mortal transport of benthic biota is well known. autochthonous and allochthonous ostracod communities in general can be distinguished by population structure (van harten, 1986). the autochthonous community contains adult specimens and numerous larval stages. larval stages, without adult valves, indicate transport, while the lack of larval stages in the community does not necessarily mean that the valves were transported, but can be a consequence of selective fossilization (pokorny, 1984). in the samples from the upper bathyal environment, the allochtonous ostracod community is represented by about 20% of the total specimens. it is mostly composed of larval stages and scarce adult specimens of shallow-marine genera aurila, semicytherura, loxoconcha, xestoleberis, callistocythere, urocythereis and olimfalunia, with broken and/or abraded valves. generally, such mixed ostracod communities are typical for steep continental margins (elewa, 2004). in contrast, the deep-water community contains adult specimens and larvae with well preserved complete carpaces (ca. 30%), thus indicating rather slow sedimentation. the complete/separated valve ratio is a very useful indicator of sedimentation rate (whatley, 1983). laboratory experiments have shown that only a few hours after death, ostracod valves are separated, due to intensive bacterial activity (pokorny, 1984). in basins with rapid deposition, most of the complete carpaces sink deep enough into the sediment, so after decomposition of the muscles and ligaments carpaces remain complete. 148 geologia croatica 60/2 6. conclusion at the sveta barbara locality miocene deposits contain a rich microfossil community in which foraminifera are the most abundant fossils with 36 benthic genera (49 species), and 4 planktonic genera (9 species). ostracods are represented by 18 genera (21 species). the studied sediments can be attributed to the bulimina–bolivina zone of the late badenian (middle miocene), due to the presence of some index fossils including p. neudorfensis and u. bellicostata, as well as the badenian ostracod taxa cnestocythere lamellicostata and aurila haueri. variations in foraminiferal and ostracod communities can be traced along the studied section, as well as significant changes in the number of specimens and taxa. three different environments can be distinguished: middle shelf, upper shelf and upper bathyal. along with the typical deep-water species, specimens of benthic taxa transported from the shallow-water environment can be clearly observed in the outer shelf and upper bathyal environments. high species diversity, average domination and significant abundance of oxic indicators and epifaunal taxa indicate the well oxygenated and nutrient rich middle shelf palaeoenvironment. dominant species are: cassidulina laevigata, cibicidoides pseudoungerianus and globocassidulina oblonga. the microfossil community of the outer shelf lived in a less oxygenated environment than the community from the middle shelf. this can be concluded from the following features: higher abundance of suboxic/disoxic indicators, particularly the species bolivina dilatata, chilostomella ovoidea and globobulimina pyrula, higher presence of infaunal taxa, significantly smaller number of species, but larger number of specimens of benthic foraminifera, lower species diversity and more prominent domination as well as the smaller percentage of porcellaneous foraminifera. a large number of specimens indicates the optimal environmental conditions for taxa tolerant to the low-oxygen content in the bottom water. upper bathyal communities are characterized by an increase in diversity, and a decrease in the number of disoxic indicators, which shows that they lived in a deeper, but better aerated benthic environment than the open shelf community. dominant taxa are uvigerina venusta, uvigerina semiornata and bolivina dilatata. ostracod specimens are scarce and relatively poorly preserved in the middle and outer shelf, while the upper bathyal ostracod community is very rich, with wellexpressed dominance of species argilloecia cf. acuminata and parakrithe dactylomorpha. our study has shown that the increase in depth of the depositional basin, and oscillations of oxygen content in bottom water, were the dominant factors influencing the composition and abundance of microfossil communities in this area. 7. references avanić, r. (1997): analiza facijesa srednjeg miocena jugoistočnog dijela medvednice [facies analysis of middle miocene of the se part of the medvednica mt. – in croatian].– unpub. msc thesis, university of zagreb, 77 p. bajraktarević, z. (1984): primjena mikroforaminiferskih zajednica i nanofosila u biostratigrafskoj klasifikaciji srednjeg miocena sjeverne hrvatske [application of microforaminiferal communities and nannofossils in biostratigraphic classification of the middle miocene in n. croatia – in croatian].– acta geol., 14/1 (prir. istraž. jug. akad. znan. umjetn., 49), 1–34. baldi, k. (1999): taxonomic notes on benthic foraminifera from sw hungary, middle miocene (badenian) paratethys.– acta geol. hungar., 42/2, 193–236. basch, o. (1983): osnovna geološka karta sfrj 1:100.000. tumač za list ivanić grad l33–81 (basic geological map of sfrj 1:100,000. explanatory notes for the ivanić grad sheet).– inst. geol. istraž., zagreb (1980), sav. geol. zavod, beograd, 66 p. bernhard, j.m. (1986): characteristic assemblages and morphologies of benthic foraminifera from anoxic, organic-rich deposits: jurassic to holocene.– j. foram. res., 16/3, 207–215. bonaduce, g., ciampo, g. & masoli, m. (1975): distribution of ostracoda in the adriatic sea.– pubbl. del. staz. zoolog. napoli, 40/1, 1–154. brestenska, e. & jiříček, r. (1978): ostrakoden des badenien der zentralen paratethys.– in: papp, a., cicha, j. & steininger, f. (eds.): chronostratigraphie und neostratotypen miozän der zentralen parathetys. badenian. verlag der slowak. akad. der wissen., bratislava, 405–439. ciampo, g. (2003): reconstruction of late pleistocene– holocene palaeobathymetries from ostracoda on the tyrrenian continental shelf.– geobios, 36, 1–11. cicha, i., rögl, f., rupp, c. & ctyroka, j. (1998): oligocene–miocene foraminifera of the central paratethys.– abh. senckenberg. naturforsch. ges., 549, 1–325. dall’antonia, b., bossio, a. & guernet, c. (2003): the eocene/oligocene boundary and the psychrospheric event in the tethys as recorded by deep-sea ostracoda from the massignano global boundary stratotype section and point, central italy.– mar. micropaleo., 48, 91–106. danielopol, d.l., ito, e., wansard, g., kamya, t., cronin, t.m. & baltanas, a. (2002): techniques for collection and study of ostracoda.– in: holmes, j.a. & chivas, a.r. (eds.): the ostracoda. applications in quaternary research. geophysical monograph 131, amer. geoph. union, washington, 65–98. de deckker, p. (2002): ostracoda palaeoecology.– in: holmes, j.a. & chivas, a.r. (eds): the ostracoda. applications in quaternary research. geophysical monograph 131, amer. geoph. union, washington, 121–134. den dulk, m., reichart, g.j., van heyst, s., zahariasse, w.j. & van der zwaan, g.j. (2000): benthic foraminifera as proxies of organic matter flux and bottom water oxygenation? a case history from the northern 149pezelj, sremac & sokač: palaeoecology of the late badenian foraminifera and ostracoda... arabian sea.– palaeogeogr., palaeoclimatol., palaeoecol., 161, 337–359. de stigter, h.c., jorissen, f.j. & van der zwaan, g.j. (1998): bathymetric distribution and microhabitat partitioning of live (rose bengal stained) benthic foraminifera along a shelf to deep sea transect in the southern adriatic sea.– j. foram. res., 28, 40–65. duijnstee, i.a.p., de lugt, i., vonk noordegraaf, h. & van der zwaan, b. (2004): temporal variability of foraminiferal densities in the northern adriatic sea.– mar. micropaleontol., 50, 125–148. elewa, a.m.t. (2004): quantitative analysis and palaeoecology of eocene ostracoda and benthonic foraminifera from gebel mokattam, cairo, egypt.– palaeogeogr., palaeoclimatol., palaeoecol., 211, 309–323. gorjanović-kramberger, d. (1908): geologijska prijegledna karta kraljevine hrvatske–slavonije 1:75.000. tumač geologijskoj karti zagreb [overview geological map of the croatian and slavonian kingdom. explanatory notes for the zagreb sheet – in croatian].– nakl. kralj. zemalj. vlade, odjel za unutr. poslove, ii, zagreb, 75 p. hajek-tadesse, v. (2006): miocenski ostrakodi sjeverne hrvatske [miocene ostracoda of northern croatia – in croatian].– unpublished phd thesis, university of zagreb, 111 p. huber-mahdi, t. (1984): beschreibung und dokumentation von ostracoden aus dem badenien von niederösterreich und burgenland.– fond. förder. wissensch. forsch., projekt p4458, 1–119. jiříček, r. & riha, j. (1991): corelation of ostracoda zones in the paratethys and tethys.– saito ho-on kai spec. publ., 3, 435–457. jorissen, f.j. (1999): benthic foraminiferal successions across late quaternary mediterranean sapropels.– mar. geol., 153, 91–101. jorissen, f.j., de stigter, h.c. & widmark, j.g.v. (1995): a conceptual model explaining benthic foraminiferal microhabitats.– mar. micropaleontol., 26, 3–15. kaiho, k. (1994): benthic foraminiferal dissolved-oxygen index and dissolved-oxygen levels in the modern ocean.– geology, 22, 719–722. kaiho, k. (1999): effect of organic carbon flux and dissolved oxygen on the benthic foraminiferal oxygen index (bfoi).– mar. micropaleontol., 37, 67–76. kochansky-devidé, v. (1944): fauna marinskog miocena južnog pobočja medvednice (zagrebačke gore) [marine miocene fauna of the southern slope of the medvednica mt. (zagrebačka gora mt.) – in croatian].– geol. vjestnik hrv. drž. geol. zav. hrv. drž. geol. muz., 2/3, 171–280. kochansky-devidé, v. (1957): o fauni miocena i o tortonskom “šliru” medvednice (zagrebačka gora) [on the miocene fauna and badenian “schlier” of the medvednica mt. (zagrebačka gora mt.) – in croatian].– geol. vjesnik, 10, 39–50. kovačić, m. 2004: sedimentologija gornjomiocenskih naslaga jugozapadnog dijela panonskog bazena [sedimentology of the upper miocene deposits from the sothwest part of the pannonian basin – in croatian].– unpublished phd thesis, university of zagreb, 203 p. loeblich, a.r. & tappan, h. (1988a): foraminiferal genera and their classification.– van nostrand reinhold, new york, 970 p. loeblich, a.r. & tappan, h. (1988b): foraminiferal genera and their classification. plates.– van nostrand reinhold, new york, 1059 p. loubere, p. (1996): the surface ocean productivity and bottom water oxygen signals in deep water benthic foraminiferal assemblages.– mar. micropaleontol., 28, 247–261. lučić, d., saftić, b., krizmanić, k., prelogović e., britvić, v., mesić, i. & tadej, j. (2001): the neogene evolution and hydrocarbon potential of the pannonian basin in croatia.– mar. petrol. geol., 18, 133–137. mazzini, i., anadon, p., barbieri, m., castorina, f., ferreli, l., gliozzi, e., mola, m. & vittori, e. (1999): late quaternary sea-level changes along the tyrrenian coast near orbetello (tuscany, central italy): palaeoenviromental reconstruction using ostracoda.– mar. micropaleontol., 37/3–4, 289–311. mendes, i., gonzalez, r., dias, j.m.a., lobo, f. & martins, v. (2004): factors influencing recent benthic foraminifera distribution on the guadiana shelf (southwestern iberia).– mar. micropaleontol., 51, 171–192. murray, j.w. (1991): ecology and paleoecology of benthic foraminifera.– john wiley & sons, new york, 397 p. murray, j.w. (2001): the niche of benthic foraminifera, critical thresholds and proxies.– mar. micropaleontol., 41, 1–7. papp, a. & schmid, m.e. (1985): die fossilen foraminiferen des tertiären beckens von wien.– abh. geologisch. bundesanst., band 37, 1–311. papp, a., cicha, i., & čtyroká, j. (1978): foraminifera.– in: papp, a., cicha, j. & steininger, f. (eds.): chronostratigraphie und neostratotypen miozän der zentralen parathetys. badenian. verlag der slowak. akad. der wissen., bratislava, 263–325. pavelić, d., miknić, m. & sarkotić šlat, m. (1998): early to middle miocene facies succession in lacustrine and marine environments on the southwestern margin of the pannonian basin system (croatia).– geol. carpathica, 49/6, 433–443. peypoquet, j.p. (1983): krithe and parakrithe in the kef section (northeast tunisia) around the cretaceous–tertiary boundary: paleohydrological implications.– in: maddocks, r.f. (ed.): applications of ostracoda. univ. houston geosc., houston, 510–519. pokorný, v. (1984): ostracoda.– in: haq, b.u. & boersma, a. (eds.): introduction to marine micropaleontology. elsevier biomedical, new york, 109–151. riha, j. (1989): ostracoda interpretation of palaeodepth of miocene (lower badenian) calcareous clays near brno, czechoslovakia.– cour. forsch. inst. senckenberg, 113, 103–116. rögl, f. (1998): palaeographic consideration for mediterranean and paratethys seaways (oligocene to miocene).– ann. naturhist. mus. wien, 99a, 279–310, wien. 150 geologia croatica 60/2 rögl, f. (1999): mediterranean and paratethys. facts and hypotheses of an oligocene to miocene paleogeography (short overview).– geol. carpathica, 50/4, 339–349. sen gupta b.k. & machain-castillo, m.l. (1993): benthic foraminifera in oxygen poor habits.– mar. micropaleontol., 20/1, 183–201. smith, a.j. & horne, d.j. (2002): ecology of marine, marginal marine and nonmarine ostracodaes.– in: holmes, j.a. & chivas, a.r. (eds.): the ostracoda. applications in quaternary research. geophysical monograph 131, amer. geoph. union, washington, 65–98. szczechura j. (1994): paleogeographic meaning of psychrospheric miocene ostracodaes from the fore-carpathian depression.– acta paleontol. polonica, 44/1–2, 137– 151. šikić, k. (1995): prikaz geološke građe medvednice [geological composition of the medvednica mt.– in croatian].– in: šikić, k. (ed.): geološki vodič medvednice. inst. geol. istraž., zagreb, 7–30. šikić, k., basch, o. & šimunić, a. (1979): osnovna geološka karta sfrj 1:100.000. tumač za list zagreb l38–80 (basic geological map of sfrj 1:100 000. explanatory notes for the zagreb sheet).– inst. za geol. istraž. zagreb (1972), sav. geol. zavod, beograd, 81 p. šikić, l. (1967): torton i sarmat jugozapadnog dijela medvednice na osnovu faune foraminifera [tortonian and sarmatian of the sw part of the medvednica mt. on the basis of foraminiferal fauna – in croatian].– geol. vjesnik, 20, 127–135. šikić, l. (1968): stratigrafija miocena sjeveroistočnog dijela medvednice na osnovu faune foraminifera [miocene stratigraphy of the ne part of the medvednica mt. on the basis of foraminiferal fauna – in croatian].– geol. vjesnik, 21, 213–225. van der zwaan, g.j., dujinstee, i.a.p., den dulk, m., ernst, s.r., jannink, n.t. & kouwenhoven, t.j. (1999): benthic foraminiferes: proxies or problems? a review of paleoecological concepts.– earth science reviews, 46, 213–236. van harten, d. (1986): use of ostracodaes to recognize downslope contamination in paleobathymetry and a preliminary reappraisal of the paleodepth of the prasas marls (pliocene), crete, greece.– geology, 14, 856–859. van morkhoven, f.b.c.m. (1962): post-palaeozoic ostracoda. general. vol. i.– elsevier publ. comp., amsterdam, 204 p. van morkhoven, f.b.c.m. (1963): post-palaeozoic ostracoda. generic descriptions. vol. ii.– elsevier publ. comp., amsterdam, 478 p. whatley, r.c. (1983): the application of ostracoda to paleoenvironmental analysis.– in: maddocks, r.f. (ed.): applications of ostracoda. univ. houston geosc., houston, 51–77. yassini, i. (1978): the littoral system ostracodaes from the bay of bou-ismail, algiers, algeria.– rev. espan. micropaleont., 11/3, 353–416. manuscript received march 15, 2007. revised manuscript accepted november 23, 2007. barudzija.indd 323 � ab stra ct “white horizon” archaeological units consisting of carbonate concretions occur in the archaeological settlement of “orovački vinogradi”, located near bjelovar (nw croatia). during archaeological excavation these horizons were considered to be the inhabitation-levels within the historical layering profi le. further sedimentological and mineralogical research and comparison of the profi le with an anthropogenically unaffected site nearby (“ciglenska strana”) required re-evaluation of this interpretation. these horizons of carbonate concretions are interpreted as the result of diagenetic processes developed within the upper pontian sequence of sands, clayey sands and sandstones. a sedimentary-diagenetic model is suggested for their formation. these results had consequences for the archaeological evaluation of the settlement and infl uenced further investigations at the locality. keywords: carbonate concretions, diagenesis, geoarchaeology, bronze age, upper pontian vučedol-culture, vinkovci-culture, croatia characteristics, origin and geoarchaeological signifi cance of carbonate concretions from the early bronze age locality „orovački vinogradi“, (bjelovar, croatia) � uroš barudžija1, goran jakovljević2, dunja aljinović1, vlatko brčić3 and neven tadej1 1faculty of mining, geology and petroleum engineering,university of zagreb, 10 000 zagreb, croatia; (uros.barudzija@rgn.hr) 2bjelovar city museum, 43 000 bjelovar, croatia 3croatian geological survey, 10 000 zagreb, croatia doi: 104154/gc.2010.26 geologia croatica 63/3 323–332 10 figs. 1 tab. zagreb 2010 geologia croaticageologia croatica 1. introduction when trying to problem solve in fi eld investigations, it is often necessary, and useful for both disciplines, to relate geology to archaeology. results of such multidisciplinary research are mostly published jointly by the disciplines, and are known as geoarchaeological results. in this article an example of the mutual application of archaeological and geological methodology will be shown. research activities were conducted on an early bronze age locality of the vinkovciculture (2100–1900 bc), named “orovački vinogradi”, located near bjelovar (north-western croatia). the site was fi rst investigated according to archaeological methodology, followed by later geological investigation in order to solve some problems of interpretation. a similar approach is often used but the opposite approach is also known (archaeological methods after geological investigation), goldberg & macphail (2006). archaeological research at the locality resulted in numerous multidisciplinary data, relevant for understanding everyday life at the beginning of the bronze age in northgeologia croatica 63/3 geologia croatica 324 western croatia (jakovljević, 2005, 2007). the settlement of the vinkovci-culture period (2100–1900 bc), which was the one of the successors of the great vučedol-culture, is so far the only settlement from this period systematically investigated in north-western croatia. research indicates aspects of the everyday life of the settlement inhabitants. valuable material discoveries including ceramics, bone and stone artifacts have been made. the results also testify to the ethnological and spiritual origin of the inhabitants as part of an extensive civilization that spread from the aegean to the baltic sea (jakovljević, 2005). “white horizon” archaeological units observed in the investigated locality occur as an interesting and puzzling phenomenon. their characteristics and origin are described and their geoarchaeological signifi cance is discussed. carbonate concretions within the profi le are interpreted and a model for their formation is proposed. both the results and the model infl uenced the archaeological interpretation and evaluation of the site and future excavation activities were directed according to the geological interpretation. 2. archaeological and geological setting the “orovački vinogradi” archaeological settlement is located 15 km west of bjelovar in north-western croatia, on a small hill within the forest (fig. 1). it is located within upper pontian clastic sediments, consisting mostly of sands and sandstones (korolija & crnko, 1985; korolija et al., 1986). the settlement is situated on a plateau with three steep sides covered with dense vegetation (beech and hornbeam forest), while the southern side is fl at and covered by meadows (fig. 2). such a location of the settlement aided preservation of the cultural layers, immediately below the humic horizon (mostly occupation deposits – dug out objects and waste pits) (jakovljević, 2007). in an area of approximately 300 m2, about 40 different archaeological stratigraphic units were investigated and registered, (including traces of inhabitation objects, layers with bones and ceramic fi nds etc.). archaeological data on the “horizontal stratigraphy” (the spatial arrangement of the archaeological objects and fi nds) obtained during the excavation provided the ground-plan of the settlement (fig. 2). colle cted data on the “vertical stratigraphy” (the vertical arrangement of fi nds in the archaeological units revealed during excavation), suggest the basic chronology of the settlement. after the archaeological excavation, two questions still remained: (i) how to precisely defi ne the basic chronology of the settlement; and (ii) of what type were archaeological objects in the settlement traditional buried dug out objects vs. combined dug out objects and surface objects. in order to answer these questions, geological research of the “white horizon” archaeological units proved very useful. some archaeological stratigraphic units (i.e. “hard rock” archaeological units – fig. 3a) are found to be archaeologically negative. rounded and triangle-shaped palisade traces (figs. 3b and 3c), which probably defi ned constructed shelters, have been discovered in different vertical archaeologifigure 1: location map, based on the basic geological map of croatia, 1:100 000, sheet bjelovar (korolija & crnko, 1985; korolija et al., 1986). barudžija et al.: characteristics, origin and geoarchaeological signifi cance of carbonate concretions from the early bronze age locality ... geologia croatica 325 cal stratigraphic units. the origin of “white horizon” archaeological units – figs. 3d and 3e) remained puzzling. they consist of semi-consolidated fi ne-grained, white marly material (fig. 4) and were considered during excavation as the inhabitation-levels within the historical layering profi le. the puzzling nature and origin of these archaeological units temporarily suspended further excavation at the locality. therefore, answers to questions concerning their nature (anthropogenic vs. natural-geological), origin (synsedimentary, diagenetic, epigenetic etc.) and their archaeological signifi cance for the future treatment of the locality (conservation of the settlement vs. continuing excavation) depended on geological research of the profi le. at the near-by site of “ciglenska strana”, (approximately 800 m away – cs on fig. 1), at the same altitude and on the slope of the nearby hill, there is a vertical outcrop with an almost identical layering sequence in the lower part of the outcrop (containing upper pontian deposits). the top of the outcrop contains younger loess deposits and is indurated and covered with vegetation. it is claimed that this outcrop was “anthropogenically unaffected” and formed solely by natural (geological) processes. observations made on this outcrop served for comparison and as a tool to understand the anthropogenically affected site “orovački vinogradi”. 3. methodology sedimentological fi eld-work methodology (after stow, 2005) was undertaken at the locality in order to determine the lithology and to describe any sedimentary textures and structures. particular representative layers were sampled for petrographic and mineralogical analysis and to precisely characterize the mineralogical and petrological composition of the “hard rock” and “white horizon” archaeological units. all results are summarized in the geological column (figs. 5 and 6a–d). the same sedimentological fi eld-work methodology (after stow, 2005) and sampling procedure were also conducted at the “ciglenska strana” site (fig. 7), in order to compare results with the “orovački vinogradi” site. thin-sections of characteristic samples from the welllithifi ed sandstones were prepared for petrographic and xrd analysis. thin-sections of sandstone samples (samples sj-17 and cs-2) were stained with “alizarin red s” and k-ferricyanide and analyzed in plane-polarized light. samples were described and interpreted in terms of the rock classifi cation after folk (1980), pettijohn et al. (1987), tucker (2001) and tišljar (2004). whole-rock samples of the “white horizon” archaeological units (samples sj-24, sj-27 and cs-1) and sandstones (samples sj-20 and cs-2) were analyzed by x-ray powder diffraction (xrd). xrd-patterns were taken using a philips diffractometer (cukα radiation, u = 40 kv, i = 20 ma) with graphite monochromator and proportional counter. samples were treated with 5% acetic acid and the diffraction patterns of air dried and variously treated (with glycerine; with ethylene glycol; 2 hours heated on 600ºc; dissolved for 24 hours in warm 18% hcl) insoluble residues are also recorded. 4. results during the archaeological excavation we examined a 7 m thick, undisturbed, vertical succession, consisting of sand and sandstone beds and horizons with white concretions. individual brownish-yellow sand beds are 0.24–1.40 m thick (fig. 5). thicker sand beds occur in the lower part of the geological column. the main structural characteristic of the sand beds is plane parallel lamination. in the upper part, well-lithifi ed sandstones up to 5 cm thick (so-called “hard rock” archaeological units) occur. sandstones alternate with thick-bedded unlithifi ed sand. boundaries between the sands and sandstones are sharp and wavy. within some of the sand beds, (usually in the upper part of the column), an upward increase in clay content was observed. such an increased clay content accompanied the “white horizon” archaeological units. sand beds consist of fi neto medium-grained sand (0.1–0.5 mm grain size) (figs. 6a–d). the main mineral component is quartz with subordinate feldspars and micas. the amount of clay minerals and fe-oxides varies. in some of the beds these components are concentrated in discrete laminae on the top of the normally graded beds. sandstones from the “orovački vinogradi” site (“hard rock” archaeological units) are predominantly composed (> 60 %), of angular, well-sorted quartz grains. feldspars and lithic fragments, (cherts and magmatic rocks), (figs. 8a and 8b) are subordinate components. between these three main types of grains there is a signifi cant amount of interfigure 2: topographic map of the archaeological settlement located on the hill slope. archaeological probes are marked g1-g5 and f1-f7 and distributed along the profi le of the settlement (a–b). scale 1:1 000. geologia croatica 63/3 geologia croatica 326 figure 3: a) geological profi le a–b along the settlement (see fig. 2); b) archaeological probe f4 with rounded and triangle-shaped palisade traces; c) archaeological probe f4 with rounded and triangle-shaped palisade traces; d) archaeological probe f4 containing “white horizon” archaeological units; e) archaeological probe f4 containing “white horizon” archaeological units. a) d)b) c) e) barudžija et al.: characteristics, origin and geoarchaeological signifi cance of carbonate concretions from the early bronze age locality ... geologia croatica 327 figure 4: photography and ground-plan of the archaeological probe f-6. “white horizon” archaeological units are marked with lines on the photography (bellow) and with dark grey areas on the ground-plan of the probe (above). locked fl akes of micas (mostly detrital muscovite), without obvious orientation of fl akes in parallel laminae. all grains are well-cemented with sparry calcite. there is minimum primary or secondary porosity (almost none). sandstones have been determined as micaceous sublitharenites. semiquantitative mineral analysis (xrd) of the sandstone samples (samples sj-20 and cs-2 in table 1) showed similar mineral composition, considering recalculation of the calcite and dolomite as the cementing minerals. the composition (defi ned by petrographic and semi-quantitative xrd analysis) of sandstone samples collected at the “ciglenska strana” locality are almost identical to those at the “orovački vinogradi”, and therefore their origin can be compared (compare figs. 8a and 8b, and samples sj-20 and cs-2 in table 1). archaeological stratigraphic units, the so-called “white horizon” archaeological units that randomly appear in the vertical section “orovački vinogradi” and ciglenska strana consist of spherical, (up to 5 cm in diameter), and partly elongated, (up to 15 cm long and from 5 to 10 cm wide) white concretions, which are mostly coalesced into semi-consolidated layers. coalescence of these concretions can be seen on the upper bedding planes of these horizons that were exposed during archaeological excavation, and preserved as possibly signifi cant vertical archaeological stratigraphic units. internally, the texture of the concretions showed no table 1: results of the semi-quantitative mineralogical analysis (xrd) for the representative concretions samples (samples cs-1, sj-24 and sj-27) and sandstone samples (samples sj-20 and cs-2) from the both sites (“orovački vinogradi” site – sj-samples; “ciglenska strana” site – cs-samples). cal: calcite; dol: dolomite; qtz: quartz; pl: plagioclasses; kfs: k-feldspars; m: micas; kln: kaolinite; chl: chlorite; chl-vrm: chlorite-vermiculite; s: smectite; ac: amorphous component; +: mineral present in the sample; -: mineral not present in the sample; ?: mineral questionably present in the sample. sample cal dol qtz pl kfs m kln chl chl-vrm s ac cs-1 72 5 3 + 8 + ? 6 + + sj-24 72 5 4 3 ? 6 + 4 + + sj-27 82 5 2 + + 3 ? ? + ? + sj-20 40 12 14 15 + 12 + + 3 + cs-2 43 22 17 4 6 + + + obvious nucleus for concretionary growth (e.g. fossil or some lithic fragment). they contain silty particles and clay, showing thin ovoid lamination that continues from the sand beds (figs. 9 and 9b). finer quartz grains, together with some clay material are incorporated into the concretions. the frequency of concretion layers in the geological column coincides with the increase in clay content in the sand beds below, which indicates a signifi cantly close relationship between the two features. semi-quantitative mineral analysis (xrd) for sevgeologia croatica 63/3 geologia croatica 328 figure 5: geological column in the site „orovački vinogradi“. eral samples of concretions from both sites (“orovački vinogradi” and “ciglenska strana”) showed very similar mineralogical compositions (samples cs-1, sj-24 and sj-27 in table 1). the concretions are predominantly calcareous, containing between 72% and 82% calcite, up to 5% dolomite, < 8 % feldspars (both plagioclases and k-feldspars), < 8% micas, clay minerals (predominantly chlorite-vermiculite and smectite, chlorite and kaolinite) and also some amorphous material. 5. interpretation and discussion results of the sedimentological and mineralogical research revealed that the investigated profi le consists of sands, clayey sands and sandstones and that it is formed by deposition of sedimentary material. the major enigma during the archaeological investigations was the presence of unusual “white horizon” archaeological units, cropping out frequently along the vertical profi le. during the geological fi eld work, it was discovered that they have been formed by the development and coalescence of concretions in particular horizons. these processes are discussed and a possible model for their formation is inferred below. concretions are usually formed by various combinations of processes, under different sedimentary and geochemical conditions. concretion morphologies strongly depend on the physico-chemical conditions operating during their formation (seilacher, 1991). their mineralogical compositions are often considered to be an important factor for the development of morphologically different concretion types (selles-martinez, 1996). mineral composition varying from mostly calcite, siderite and silica, together with concretions morphologies, can be indicative of their origin (syngenetic, diagenetic or epigenetic). examples of epigenetic concretions formed by meteoric groundwater are calcareous concretions in loess, or sideritic concretions in desert sandstones. the former are also known as “loess dolls”, and sometimes are even wrongly named as “neolithic mother goddesses”. concretions from the investigated profi le do not match that type of epigenetic concretions because of their different morphology, fabric and composition, together with the characteristics of the host sediments, which are not aeolian sediment (loess). diagenetic concretions (preor postcompaction), usually contain calcite, dolomite or silica, depending on the material available from the surrounding sediment. concretions can be formed around some nucleus or, more commonly, without any nucleus, along particular horizons, refl ecting a level at which super-saturation of porewaters was achieved (tucker, 2001). super-saturation of the pore-waters is often achieved when the clay content dispersed in the host sediment increased, usually forming a kind of vertically impermeable screen. concretions may also be preferentially developed in horizons with increased organic carbon, compared to the surrounding sediments. in both of the investigated sites, an increased amount of clay was noticed immediately below the “white horizon” archaeological units, suggesting their close relationship. therefore localized precipitation from adequate pore-waters under suitable geochemical conditions controlled the mineralogy and growth rates of concretions. in the case of carbonate concretions from the “orovački vinogradi” and “ciglenska strana” sites, the available material from the surrounding sediment, (predominantly quartz sands with micas, occasionally cemented with sparry calcite cement, thus forming micaceous sublitharenites) was most-likely calcite precipitated from pore-waters. finer quartz grains, together with some clay material were incorporated in particular horizons during growth of the concretions. barudžija et al.: characteristics, origin and geoarchaeological signifi cance of carbonate concretions from the early bronze age locality ... geologia croatica 329 in terms of concretion morphology, all concretions usually occurred as two radically different morphospaces, either as dendrites or as liesegang rings (seilacher, 2001). both morphotypes result from the distribution and percolaa) c) b) d) figure 6: a) “white horizon” unit. ruler (20 cm) for scale (see in fig. 5); b) individual carbonate concretions within “white horizon” unit. hammer (33 cm) for scale (see in fig. 5); c) plane parallel lamination in the sand bed. ruler (20 cm) for scale (see in fig. 5); d) “hard rock” unit (sandstone). scale bar segments are 10 cm (see in fig. 5). figure 7: a) internal structure of the concretion – continuing lamination from the sand bed. view from the top of the concretion. scale bar is in centimetres; b) internal structure of the concretion – continuing lamination from the sand bed. cross-cut of the concretion. scale bar is in centimetres. tion of pore fl uids that contain dissolved ions within the sediment. however, their appearances are not the subject of this article. instead, we would like to pay attention to the most commonly appearing concretion morphologies – ovoid and a) b) geologia croatica 63/3 geologia croatica 330 a) b) figure 8: microphotographs of the representative sandstone samples from “orovački vinogradi” (sample sj-17 – fig. 8a) and “ciglenska strana” sites (sample cs-2 – fig. 8b)). both samples are determined as micaceous sublitharenites with angular, well-sorted, (0.1 – 0.5 mm of grain size) of quartz grains that predominates, feldspars and micas and with some lithic fragments (cherts and magmatic rocks). grains were cemented with spary calcite cement. a) sample sj-17 (sample stained with alizarin red s and k-ferricyanide); b) sample cs-2. (sample stained with alizarin red s and k-ferricyanide). figure 9: vertical profi le in the anthropogenically unaff ected site „ciglenska strana“. hammer (33 cm) for scale. globular (scotchman, 1991; coleman & raiswell, 1995), because similar morphologies appear in the investigated archaeological sites. concretionary growth is the result of radial concentric precipitation of material and carbonate is usually supplied by diffusion from the surrounding sediment. if supersaturated ground-water fl owed past the growing calcite concretion, dissolved material could be added not only by diffusion, but by mass fl ow. however, very low groundwater fl ow-rates have a relatively low infl uence on the growth rate of concretions (berner, 1968, 1971). elongate concretions may be sometimes preferentially oriented, refl ecting the direction of high pore-water movement (mcbride et al., 1994). the observed concretions are sometimes elongate, but they do not show any evidence to indicate the possible direction of pore-water movement. an increased clay component in some horizons helped precipitation and concretions preferentially developed along these horizons suggesting circulation of water through the bed, and then horizontally along an impermeable clayey screen. concretions are therefore interpreted as diagenetic – they developed after deposition of the sand beds due to the circulation of pore water precipitating calcite around some invisible cells. geometries of the concretions are the result of the host lithologies, their fabric and their characteristics. the most important characteristics are the permeability and anisotropy of the host sediment. an important step in concretion geometry analysis and interpretation of their formation was to explain the interference of concretionary growth and compaction. spherical growth refl ects isotropic sediments (i.e. sand or mud), ellipsoidal growth refl ects the vertical reduction of permeability caused by compaction, and so-called bread-loaf geometries (with a fl attened lower side) refl ects a steep compaction gradient (seilacher, 2001). lensoid geometries of the concretions, in which the original lamination pinches out towards the edges within the calcifi ed part, implies the pre-compaction phase of concretionary growth. similarly, the absence of pinching out of the original lamination and the presence of a hard nucleus with the general symmetry indicate a post-compaction phase of concretionary growth (seilacher, 2001; stow, 2005). barudžija et al.: characteristics, origin and geoarchaeological signifi cance of carbonate concretions from the early bronze age locality ... geologia croatica 331 timing of concretion development is determined from analysis of their geometry and their geometric relationships with the surrounding beds. continuation of depositional laminae from the sand beds to the concretions was observed, as well as slight pinching of the lamination in the surrounding sands towards the edges of concretions. concretions show ovoid geometry, which again suggests development during the diagenetic phase, (after sedimentation of the overlying sand bed). concretions grow from pore-waters super-saturated with carbonate, along anisotropic horizons enriched in clay. the main processes were diffusion followed by laminar pore-water fl ow along partly developed concretions. carbonate concretions in all horizons, at both sites, are therefore interpreted as having developed in the pre-compaction stage of diagenesis. however, the geometries of some elongated concretions observed in the profi les also suggest a post-compaction infl uence seen in the morphology of the concretions. considering the relatively small volume of overlying sediments (only a few metres or even a few decimetres), together with their semi-lithifi ed nature, a post-compaction infl uence can be considered as the minor control for development of the observed concretions. consequently, the pre-compaction factors (precipitation caused by super-saturation of pore-waters along the particular horizons enriched in clay component), can be considered as the major control for development of the concretions. all the above-mentioned data can be summarized in the 4-stage diagenetic model of carbonate concretion development during the pre-compaction phase of diagenesis (fig. 10): 1. deposition of a sedimentary succession consisting mostly of sand beds with enrichment in clay particles along particular horizons. 2. development of concretions by diffusion from carbonate-rich pore waters. the source of carbonates was the surrounding sediment, (sand with carbonate-rich porewaters). concretions grow by mineral precipitation around anisotropic centres within horizons enriched in clay. figure 10: model for diagenetic development of carbonate concretions in the pre-compactional phase of diagenesis. stage 1) development of sedimentary column and enrichment in clay particles along the particular horizons. stage 2) beginning of the concretionary growth by diff usion. stage 3) further development of ovoidal geometry of the concretions by laminar pore-water fl ow along partly developed concretions. stage 4) coalescence of the concretions in a single semi-consolidated layer and the formation of the “white horizon” archaeological units. geologia croatica 63/3 geologia croatica 332 3. further growth of the concretions by pore-water circulation along partly developed concretion horizons. crystallization of cortices covering preformed parts of concretions and preservation of original lamination from sand beds. partial incorporation of silty material from the surrounding sediment, (quartz, feldspars and micas). 4. coalescence of concretions into a single semi-consolidated layer and formation of the “white horizon” archaeological units. minor post-compaction infl uence on the concretion geometries. 6. conclusions according to the results of the fi eld-work presented here, and comparison of the analysis from the two investigated localities with pontian sediments, – archaeological profi le at “orovački vinogradi” site and geological profi le at “ciglenska strana” site – several conclusions about the characteristics, origin and geoarchaeological signifi cance of the observed carbonate concretions can be made: a) the investigated profi le on the archaeological site “orovački vinogradi” comprising beds of sand, clayey sand, sandstone and “white horizons” archaeological units, developed by natural (geological) processes of sedimentation and diagenesis. b) the “white horizons” archaeological units consist of carbonate concretions, developed by precipitation of carbonate from super-saturated pore-waters, along particular anisotropic sand beds enriched in clay. c) morphologies of the carbonate concretions and their geometric relationships with the surrounding sediments indicate their development in the pre-compaction phase of diagenesis. d) the main processes involved in development of the concretions were diffusion and subsequent pore-water movement along previously developed parts of the concretions. e) coalescence of the concretions in semi-consolidated layers, and the formation of the “white horizon” archaeological units within the investigated archaeological profi le, gives a false impression of anthropogenic affected horizons. the interpretation pre sented here and the geoarchaeological signifi cance of these concretions indicates continuing excavation on the site, without the specifi c need for conservation of these horizons. f) the given interpretation and model for the origin of the observed carbonate concretions suggesst the need for a fi nal re-evaluation of basic chronology of the settlement, provided by archaeological data on the “vertical stratigraphy”. h) the defi nition of types of archaeological objects in the “orovački vinogradi” settlement will be less complicated, considering the “white horizon” archaeological units are naturally developed and coalesced carbonate concretions. acknowledgement this work is partly supported by ministry of science, educaton and sports of the republic of croatia, project no. 195-1953068-2704. references berner, r.a. (1968): rate of concretion growth.− geochim. cosmochim. acta, 32, 477−483. berner, r.a. (1971): principles of chemical sedimentology.– mcgraw-hill, new york, 240 p. coleman, m.l. & raiswell, r. (1995): source of carbonate and origin of zonation in pyritiferous carbonate concretions: evaluation of a dynamic model.− am. j. sci., 295, 372−376. goldberg, p. & macphail, r.i. (2006): practical and theoretical geoarchaeology.− blackwell, oxford, 454 p. folk, r.l. (1980): petrology of sedimentary rocks (3rd ed.).− walter geology library, univ. of austin, 182 p. jakovljević, g. (2005): antropomorfna fi gura iz naselja vinkovačke kulture u orovačkim vinogradima kraj bjelovara.− histria antiqua, 13, 49−55. jakovljević, g. (2007): orovački vinogradi.− hrv. arheol. god. 3/2006, 109−110. korolija, b., vragović, m., crnko, j. & mamužić, p. (1985): osnovna geološka karta sfrj 1: 100000, list bjelovar l 33–82 [basic geological map of sfry 1:100000, bjelovar sheet – in croatian].– geološki zavod zagreb, savezni geološki zavod, beograd. korolija, b. & crnko, j. (1986): osnovna geološka karta sfrj 1: 100000. tumač za list bjelovar [basic geological map of sfry 1:100000, geology of the bjelovar sheet – in croatian].– geološki zavod zagreb, savezni geološki zavod, beograd, 45 p. mcbride, e.f., dane picard, m. & folk, r.l. (1994): oriented concretions. ionian coast, italy: evidence of groundwater fl ow direction.− jour. sed. res., a64-3, 535−540. pettijohn, f.j., potter, p.e. & siever, r. (1987): sand and sandstone (2nd ed.).− springer-verlag, new york, 553 p. tišljar, j. (2004): sedimentologija klastičnih i silicijskih taložina.− institut za geološka istraživanja, zagreb, 426 p. tucker, m.e. (2001): sedimentary petrology – an introduction to the origin of sedimentary rocks (3rd ed.).− blackwell, oxford, 262 p. selles-martinez, j. (1996): concretion morphology, classifi cation and genesis.− earth-sc. rev., 41, 177−210. scotchman, i.e. (1991): the geochemistry of concretions from the kimmeridge clay formation of southern and eastern england.− sedimentology, 38, 79–106. seilacher, a. (2001): concretion morphologies refl ecting diagenetic and epigenetic pathways.− sed. geol., 143, 41−57. stow, d.a.v. (2005): sedimentary rocks in the field.− manson publ., london, 320 p. manuscript received may 28, 2010 revised manuscript accepted september 28, 2010 available online november 11, 2010 geol. croat. 51/2 135 162 3 figs. 1 pi. zagreb 1998 problems for evaluation of the scenario of the permian -triassic boundary biotic crisis and of its causes heinz w. kozur key words: pit boundary, biotic crisis, extinction and recovery patterns, volcanic winter, superano­ xla. abstract determination of the causes o f the permian -triassic boundary (ptb) biotic crisis is hindered primarily by the diachronous nature of the used ptb, poor stratigraphic control of compared upper permian and lower triassic faunas, espec ially in cont inental biotopes, poor knowledge of the lower and midd le scythian faunas from m,uly envi­ ronments, and by interpolation of the unknown (lower and middle) scythian diversity from the known upper pennian and middle trias­ sic diversity data in many major fossil gro ups. most of these prob­ lems can be reso lved by using the firs t appearance datu m (fad) of nil1deodlls pan'ii,i' as either an isochronous ptb, or as an isochronous marker [eve i very dose 10 lhe base of lhe triassi c; careful studies of fossil-rich, comp[ele conlinental boundary sections (e.g., dalongkou in sinkiang), and uti li sation of uninterpojated diversity data, which are based on known scythian data, for the reconstruction of the extinction and recovery patterns in all fossil groups. the most important features of the ptb biotic crisis arc: (i) among the marine biota, only the pl ankton and the wann-water ben­ thos, nektobenthos and nekton are strongly affected by the ptb biotic crisis . (2) the recovery of the warm-water nekton and nektobenthos was very fast (after one conodont zone). the recovery of the warm­ water benthos, some of the plankton (radiolarians) and the terrestrial plant product ivity was strongly delayed for several million years, and occurred on ly in the upper olenekian (upper scythian) and in the middle triassic. (3) the number of the lazarus taxa that re-appeared in the upper olenekian and above all in the middle triassic, is very high (about 50%) and in some fossi l groups 90-100% at generic le­ vel. the reconstruction of the scenario for the ptb biotic crisis requires not only the cons ide'rlition of the uninterpolaled extinction and recovery patterns of all foss il groups across all envi ronments, but must also account for the main feat ures of geological evolution from the middle permian to the lower triassic. the most important causa l factors in the ptb biotic crisis are the ex tinction event at the guadalupianlopingian boundary that restricted the diverse upper permian wann-water benthos 10 the tet hyan shelves, the long-[asling, widespread siberian trap volcanism (dzhulfian lower scythian) which was ihe grealest volcanic event during the phanerozoic, and (he very strong explosive felsic 10 intermediate volcanism around the ptb, close to the margin between eastern tethys and panlhalassa. these volcanic activities resulted in those climatic changes that were dircclly and indireclly (as cause of the oceanic sll peranoxia) responsi ­ ble for the ptb biotic crisis, such as periodic cooling of ihe climate by volcanic dust and sulphate aerosols (mai nly caused by the siberian trap volcanism), acid rain, a 3-6 month "vo[canic winter" at low lat i­ illdes and ihe strongly reduced inpul of sunl ight during the uppennost dorashamian (both caused by lhe very strong explosive volcanism at the tethys/panthalassa margin), followed by global warming in the lower scythian, and uppennost dorashamian to lower scylhian super­ anoxia . rezsti li. 83, h-[029 budapest, hungary. 1. introduction the search for the causes of the biotic crisis around the penniantriassic boundary (ptb) requires the inve­ stigat ion of the exact scenario of the ptb biolic crises (extinction and recovery patterns among all major fau ­ nal and floral groups of all facies) and the exact g lobal correlation of these patterns. it also requires considera­ tion of accompanying geological phenomena (e.g., faci es changes, climatic changes, age and character of volcanic activity around the ptb, changes in stable iso­ topes, the distribution and vertical range of the oceanic anoxi a) . these investigations have been hampered by (1) incorrect correlation of the ptb in different faunal realms and facies; (2) erroneous assignment of strong bi otic changes at diachronou s facies boundaries to the ptb biotic changes; (3) erroneous assignment of strong biotic changes, occuring between permian and triass ic continental biota that are separated by a long time gap, to the ptb biotic crisis; (4) comparison of permian and triass ic faunas with poor st ratig raphi c control; (5) inadequate knowledge of the lower and middle scythian pelagi c faun as; (6) interpolation of the unknown or poorly known (lower and middle) scythian diversity of major fossil groups from known upper permian and anisian diversities. in the present paper some of the problems in the search fo r the real extinction and recovery patterns and the most important features of the ptb biotic crisis are indicated. on the basis of the real (not interpolatcd) ext inction and recovery patterns of the major fossil groups, and with consideration of the geological phe­ nomena in the upper permian and lower triassic, a possible scenario for the pte biotic crisis is presented. 2. position and correlation of the permian -triassic boundar v the following leve ls are, partly for historical rea­ sons, the most important ptb levels used in marine and continental beds: (1) the base of the buntsandstein in the southwestern germanic basin; (2) the boundary bctween the bellerophon limestone and the werfen group in the southern alps; (3) the base of the 010· ceras woodwardi zone in eastern perigondwana; (4) the basc of the otoceras concavum zone in the arct ic; (5) the first appearance datum (fad) of lystrosaurus in 136 geologia croatica si/2 himalaya meishan selo n9 south. alps greenla nd arctic canada germanic basin prio nolobus , g rotu ndatus , bernburg formation a , n , siusi u. brevifor mis d i pleura gyronites member cornia ger mari v. sverdrupi a pie urogyr. k' i 'd b, rsatus , pia nidorsatus , a l p ani 0 , s , p. candid us ca , n' , red, above yh , 9 , iimnic, below t y' s' andraz p. rosenkr antzi c, mostly sabkha ha i, h' b. strigatus a' in g a' horizon i, op hiceras n l rlophice 'as w. decipie ns ai a tibe ticum k i e i tibeticu m (evaporitic) ~: sandy claystone nan 8 1boundary bed ~ i ri member n9 n, f' -e d, t 9, m' oph. com mune oph. comm. e' i , a f , , f, variegated o. woodwardi o,d 10. woo dwardi n mazzin 0' ',boundary member t. pascoei i " m,c bed 2 , o. "iati lobatum" a, , a' iii ., i i a+b m. subdem otoeeras i i clayey sandstone 0 iss d 0' n, h martini boreale 5.1. nl member 0 i boundary bed 1 j ("graubank zone") , 250 my-a , ~ , s ooille hypoph. tr male , h , a o. b'bckel~~ llrr concavum changxing i .. 0' schiefer p a limestone ? 7 s.s. i n lfill n 6 g l-i a bellerophon 5 nd limestone iz formation 4 h u kul ing longtang ~ zechstein i for mation formation 3 f i ia schuchert 2 n ln dal forma tion spiculitic chert 1 1a fig. i coitelation chart of some important marine and continental successions. detailed on ly around the ptb. vertical scale not thickncssor time-related! the upper capitanian part is on ly shown for the ru ssian platfonn and the timan-petchora basin. after baud et al ( 1996), cheng el at. (1989), jin el at. (1996), kozur (1989. 1994b, 1996b), kozur & seidel (1983), kozur cl at. (1996b), krystyn & orchard (1996), lozovskv (1993), lucas ( 1993), perch·nielsen el at. (1974), renne el at. (1995), sadovnikov & orlova (1993), teichert & kummel (1976), tozer (1967), tuzhikova (1985), xia & zhang ( 1992), yin cl at. (l996a, b). figure la: marine sllccess ion and germanic basin (marine and continental, ptb continental); figure ib (opposite page): continental suc­ cessions and germanic basin. legend: ..... = used pff boundary (fad of hindeodlls parl'us in marine beds). the following abbrevia­ tions are used unly in figure i b: g = uppennost guadalupian series; c = upper capitanian stage; gill m = iii m above the base of the ouodikeng fm. in the dalongkou section etc. measurement after lucas (1996, during a joint project sponsored by the nos, usa); 1 200 m = 200 m above the base of the liucaiyan fm. in the xiao!ongkou secti on. conlinental beds; (6) the fad of ihe conodont hindea· dus parvus (kozur & pjatakova). these different ptb levels are moslly equated with each other, but are by definition situated at different stratigraphical levels. the base of the buntsandstein in sw gennany, the priority base of the triassic (von alberti, 1834), is a diachronous facies boundary within continental beds (kozur, 1994b, 1998a) which is only of historical interest. it has it s lowest position at the margin of the germanic basin (including the triassic type area in sw germany), where zechstein equivalents of the central germanic basin , such as the brockelschiefer, leber­ schiefer and tigersandstein were included in the buntsandstein, but also lies in upper permian dora­ sham ian stage within the centre of the germanic basin (figs. la & b). the base of the werfen group (base of the tesero oolite) was equated with the base of the triassic in the germanic basin and placed at a level where the diversi­ ty of a rich upper permian fauna and marine flora of kozur: problems for evalualion oflhe scenario of ihe pennian-triassie boundary ... 137 oalongkou-xlaolongkou (tianshan) germanic basin ~~----t-----+'-,------~-----------+----------r---------,--------------~ g bernburg formation : i russian piau. timan-petchora sa. siberian platform a krasnobakovs~ 1 supra-basaltic beds 1 n 'member 1 d ' , a i vi 1 b r i ol'---____ --h not investigated 1 s r cl red, above kl 1 c a a l limnic, below hi i y h ii i t v i mostly sabkha ml 1 ;, hag 6 1 al ryabinsk 1 l? a d:sandy claystone nl member 1-_____ : n a ~ elmember _ . f: j 200m i lad lystrosaurus and n e 1 01 ustkelterian fm. jiucaiyan i falsisca t fi . d r i formation " " 0 t variegate cc---,----rrn ml astashich , u.lu.j..llll.lu.!..llu.'-4 ______ -1 a rl al i g 234.7m --, n ml i i mbr. g 219m i, lad dicynodon .' . , " ~ i 01 iiclayey sandstone nl o ~imember : 1("graubank zone" , ' , o basalts marininskian fm. puturanian basalt 250my g210m g171.2m g 161m , , i fad falsisca verchojan. i lad falsisca postera , a • h brockel=uw i ________ i-----------1t • i fad lystrosaurus , , a l . 0' pa i n n g i ad nz h _. schiefer u 7 s.s. i-6 ls i-4 u rzechstein i 3 intra-basaltic beds (basalis with sedimentary intercalations) sub-basaltic beds , ; , m t, y u, r fl i " . al hunglukunian n c 1 formation ., 0, s t u, • " 9 , . guodikeng: fad falsisca postera? formation 1 fad falsisca eotriassic g 111m ' g 107m , i lad megasitum, i bipemphigus, i tripemphigus ' i--! 2 mttl"ttrttttl"ttrrrrrl s 1~ 1 lebedevian , , , , , , n i-1 i l fm. ., g6sm i first falsisca in the ii i ii i i i111 1111111111 upper tatar. u.j..l~1.u.lulu.1.u.lu.j..llt..js i tutontchan. i guodikeng formation 1------,1 and in siberia , wutonggou fm. i , gc (vjatka) upper t atarian ihe bellerophon limestone formation suddenly drops to a very low dive rs ity fauna and flora of the tesero ooli te. however, as shown by kozur ( 1994b), thi s boundary is also a diachronous facies boundary within the upper pennian. the decrease in diversity is caused by the change from a highly diverse shallow-water shel f community into a low-diversity tidal flat commu­ nity. such facies change is always accompanied by a drastic decrease in diversity, independent of the strati ­ graphic level within the pennian or triassic. the base of the triassic at the base of the werfen group is also only of historical interest, but this bound­ ary has been, by many authors, erroneously correlated with the biostratigraphic ptb at the base of the o. woodwardi zone (e.g. diener, 1912; tozer, 1988; posenato, 1991). however, comparison of conodont di stribution in the lowermost werfen group (kozur , 1989, 1994b, 1996b, 1998a) and in the o/oceras faunas (matsuda, 198 1; kozur, 1989, 1994b, 1996b, i fm. , lilt iitt ii itt ii itt ii in i 1b 1998a; krystyn & orchard, 1996; kozur et ai., 1996b; wang et ai. , 1996; yin et ai. , 1996a) indi­ cates that the base of the o . .. voodwardi zone is corre­ latable with the middle part of the mazzin member, considerably above the base of the werfen group (fig. i a). the base of the oloceras woodwardi zone is the first biostratigraphica ll y defined ptb (griesbach, 1880) , and the finally defined ptb should be at, or close to this boundary. the disadvantage of this bound­ ary is that o. woodwardi griesbach is only known from the perigondwana margin of eastern tethys. the fad of o. woodwardi was, therefore, onl y tentatively correlatable with the tethyan and the boreal realms. instead of bi ostratigraphic correlat ions, the fad of o. woodwardi was equated with those different chronos­ tratigraphic levels that were in different regions used as the ptb , e.g. with the basc of the werfen formation (e.g. diener, 191 2; tozer, 1988), wi th the base of 138 thc otoceras col/cavum zone (c.g. tozer, 1967) or with the base of the o. boreale zonc (e.g. dagys, 1994). howcvcr, with the aid of conodonts, it can be shown that nonc of these boundaries corresponds to the fad of o. woodwardi (kozur, 1989, 1994a, 1995a, 1996b, 1997c, 1998a). the base of the otoceras concavum zone is pre­ fcrred as the base of the t riassic by most ammonoid workers. this is largely based on the erroneous assump­ tion that otoceras begins in the arctic and in perigond­ wana at the same levcl (tozer, 1967) and that oto­ ceras is the first triassic genus. in reality it is the last representative of the upper permian otoceratacea that straddles the ptb. the main disadvantage of definition of the ptb with the base of the o. coflcavum zone arc: (1 ) o. concavwn is known only from very few localities in remote areas of arctic canada and ne siberia; (2) o. collcavllm tozer al ways follows after a gap or at least after a lengthy ammonoid-free interval; (3) the direct fore runner of o. concavum is unknown. the latter two reasons prevent the base of the o. concavum zone from being palaeontologically defined within a phylomor­ phogenetic lineage between two species. thi s excludes the definition of the base of the triassic with the fad of o. concavunl. moreover, conodont and sporomorph data have shown that the boreal oloceras faunas (with the excep­ tion of the uppennost o. boreale zone s.l.) are penn ian in age, if the fad of o. woodwardi or the insignifican­ tly older fad of h. parvus zone are used to define the basc of thc triassic (kozur, 1989, 1994a, 1995a, 1996b, 1997c, 1998a; henderson, 1993; hender­ son & baud, 1996). this was subsequently con­ firmed by ammono id data by krystyn & orch­ ard (1996) who pointed out that o. woodwardi is more advanced than o. borea/e, and that the o. wood­ wardi zone occurs in the selong section in tibet in a stratigraphic succession above a fauna with oloceras of thc o. boreale group (0. latilobatum wang & he, according to kr ystyn & orchard a junior syn­ onym of o. jissiseiiatllm diener). this was the first usage of ammonoids to show the perigondwana o. woodwardi zone is younger than the boreal otoceras faunas, whereas all ammonoid workers prior to kry­ styn & orchard (1996) had correlated the o. woodwardi zone either with the o. boreale zone (e.g., dagys, 1994) or with the o. concavum zone (e.g., tozer, 1967). therefore, the contradiction between the conodont and ammonoid correlations of the boreal and peri gondwana otoceras fauna has been resolved and the o. concavum zone proven to be two ammonoid zones older than the o. woodwardi zone (which is, according to priority the oldest triassic ammonoid zone, see above). the fad of lystrosaurus is used in continental beds to define the base of the triassic. in most places, the first occurrence of lystrosaurus is within the lower­ most triassic , but not necessarily at its base. the fad of lystrosaurus, however, can only be found in two geologia croatica 51/2 areas, in south africa and in dalongkou (sinkiang). in both areas, there is an overlap with the upper permian index genus dicynodon. in dalongkou, the interval with the co-occurrence of lystrosaurus and dicynodon contains the conchostracans falsisca eotriassica koz­ ur & seidel and f. postera kozur & seidel. these conchostracans occur in the late dorashamian (kozur, 1989, 1993; kozur & mock, 1993), whereas the lowermost t riassic (gangetian substage) contains f. verchojan;ca molin. this latter species occurs in sinkiang, in beds with lystrosaurus, above the last occurrence of dicynodon, and its fad is in the uppermost beds with dicynodoll. thus, the interval with the co-occurrence of lystrosaurus and dicynodon belongs to the dorashamian, perhaps with the exception of its uppermost part, in which f. verchojanica is already present. the fad of lystrosaurus lies therefore within the uppermost permian, but beds with lystro­ saurus that lack dicynodon are of triassic age. the fad of the conodont hindeodus parvus, which is well recognizable within a phylomorphogenetic cline h. iypicalis h. latidentatlls praeparvus h. parvlls, can be traced in all marine facies and fauna l realms. it is common in ammonoid-free, shallow-water deposits of tethys, perigondwana, the circum-pacific area (western north america and japan), and the boreal realm. it is moderately common to rare in ammonoid­ bearing pelagic rocks in peri gondwana and in the arc­ tic, where the cool-water clarkina car;l/ala group is better adapted to pelagic environments and mostly pre­ dominates. h. parvus is especially common in pelagic deposits of the basal triassic h. parvlls zone in western and central tethys. this facies is dominated by gondo­ lellid conodonts (cim'kina) in the upper permian and in the lower triassic above the h. parvus zone. howev­ er, after the disappearance of the upper permian warm­ water gondolellid fauna (c. sllbcarinata group), at or a little below the ptb, the western and central tethys has no gondolellid conodonts in the h. parvlls zone, no t even in the slope fac ies favoured by permian and trias­ sic gondolell id conodonts. in the isarcicella isarcica zone, gondoleliids of the cool-water c. carinata group invaded the pelagic environments of the central and western tethys, after they had adapted to warm-water conditions. in the upper permian , the c. carinata group is only present in the arctic and in perigondwana. h. parvlls begins in perigondwana a few centime­ tres below the o. woodwardi zone in the uppennost o. boreale zone, and it occurs only in the uppermost part of the boreal o. boreale zone (kozur, 1995a, 1996b, 1997c; henderson & baud, 1996). in greenland, it occurs above the otoceras-bearing beds of the o. boreale zone $.s., and below the ammonoid-dated beds of the ophiceras commune zone, in beds with small hypophiceras, tompophiceras gracile (spath) and t. pascoei (spath) that indicate the t. pascoei zone. according to dagys & ermakov (1996) this zone corresponds to the uppermost o. boreale zone s.l. it may be used, however, as an independent zone. kozur; problems for evaluation of the scenario of lhe penn ian-triassic boundary ... henderson & baud (1996) reported two spec i­ mens of hindeodus c f. parvus from the o. boreale zo ne s.1. of arctic canada, without any indication of the exact level within this zonc. in the lecture at the 30th igcp in be ijing, they presented photos of these specimens that are fragmented form s that cannot be exac tly determined because the cusp is broken away. it cannot be excluded that they belong to h. pm·viis. their occurrence was shown in the uppermost part of the o. boreale zone s.1. thi s occurrence fit s we ll with the fad of h. parv/.ls in greenland and in perigondwana. in tethys, h. parvlls was found in a ll conodont­ bearing rocks of the lowermost triassic, e.g., in meis­ han and other localities of south ch ina , in malaysia , iran , azerbaidzhan, annenia, turkey, hungary, in the dinarides, southern alps, and in western sic ily (italy). it is al so present in the circum-pacific area (westcrn north america and japan paull & pa ull, 1994; igo , 1996; koike , 1996). in con trast, gondo lellid conodonts have a very restricted distribution in the low­ ermost triassic h. parvus zone. they are not only mis­ s ing in the predominant shallow-watc r depos its of tethys , perigondwana and the circum-pac ific area, but a lso in pe lagic and slope deposit s of the western and central te thys. they are also absent in the most ammonoid -beari ng deposits of ne-siberia. thus , the fad of h. parvus is the only palaeontological datum that can be found in all the marine deposits of the world . using thi s datum , the marine deposits around the ptb can be well correlated (figs. la & b). as the fad of h. par viis a lmost coincides wi th the base of the o. woodwardi zone, the priority ptb , most authors regard the fad of h. parvlfs as the most suitab le marker for the base of the triass ie (yin, 1985, 1993; kotlyar et ai. , 1993; kozur , 1994a, 1995a, b, 1996a, b, c, d, 1997a, b, e, d ; paull & paull, 1994; wang , 1994, 1995a, b, c, 1996; z hu et ai. , 1994; ding e t ai., 1995, zhang e t ai., 1995, 1996; igo, 1996; kozur et ai., 1996b; lai e t ai., 1996a; wang e t ai. , 1996; wignall & hallam, 1996; wignall e t ai., 1996; yin e t ai. , 1996a, b; yin & zhang, 1996; hal lam & wignall, j997; wang & wang, 1997; zhu & lin , 1997). for evaluation o f the ptb biotic crisis it is impor­ tant that the fad of h. parvlts (base of the triassic) is situated in the middle part of boundary bed 2 (middle part of bed 27) in meishan , within the midd le mazz in member of the southe rn alps, within the e2 member of the khunamuh formation of kashmir, wit hin the middle kathwai member of the mianwali formation of the salt range, in red shales immediate ly be low large stromatolite bod ies in transcaucasia and nw iran, and within the uppermost o. boreale zone s. 1. (= t. pascoei zone) of the arctic. in continental beds, this boundary is close to the disappearance of the typical pe rmian dieyl/odoll afte r an interval of co-occ urrence of lystrosaurus and dieyllodofl. the direct correlation of the fad o f h. parvus in marine beds and the indirect co rre lations (mainly wi th conchostracans and sporo139 morphs) in important continental sections is shown in figs. l a & b. 3. problems related to the various levels of the ptb in different facies and faunal realms the exact correlation of a s uitabl e marker leve l close to the ptb is more impo rtant than the actual posi­ tion of the ptb for the evaluation of the ptb biotic cri ­ sis . the fad of h. parvus is such a marke r level, whether this bioevent is chosen as the base of the trias­ sic or not. as the base of the perigondwana o. wood­ wardi zone, the priority base of the triassic, is only a fe w em higher than the fad of h. pm'vl/s, the fina lly approved ptb will be, in a ll cases either very close to, or at the fad of h. parvi/s, which in the followin g dis­ cussions is used as the base of the triassic. the fonner diachronou s corre lations o f th e ptb be tween the perigondwana margin and tethys, within the tethyan realm and above all , be tween tethys and the boreal realm , had strong ly hindered the evaluat ion of the biotic c ri sis. for instance , the prev ious correla­ tion o r the triassic base at the base of the o. woodwar­ di zone with the base o f the werfen group in the southern alps and with base of the o. col/cavum zone in the arctic, had the obvious following consequences for the age of the mass occurrences of fung i: in the pe lag ic to s lope success ion of south china, the mass occurrences of fungi wcre in the uppermost pe rmian, the pe rcentage of fungal spores dropped be low i % at the base of the boundary beds and fungal spores are practically absent in the triass ic. in the southern alps the mass occultence of fungi would begin in the uppe r­ most pe rmian and reaches it s peak in the lowe rmost tri ass ic t esero oolite. in the arc tic, the mass occur­ rences o f the fungi would be totally within the t riassic. taking these dis tribu tion patterns, the mass occurrence of fung i around the ptb would not have any spec ial signi ficance. takin g the fad of h. parvus as an isochronous marker horizon and base of the triassic, then the g lobal mass occurrences of fun gi, independent from the faunal and flora l realm , would be be fore the fad of h. parvlls with in the uppermost pe rmi an. the mass occurrences decrease everywhere drastically a little before the fad of h. parvus and above the fad of h. parvlis, fungal sporcs are very rare. thus, the extinction patte rn of fun ­ gi is totally different using previously accepted diachro­ nolis ptb corre lat ions or the isochronous marke r hori ­ zon (fa d of h. parl'lis). si milar modifications o f the detailcd cx tinc tion patte rns can be observed for other fossil groups. the fomler ass ignment of the borcal otoceras fau ­ nas to th e triassic has al so caused assignment of all sporomorph associations with a high percentage 01" tri­ le te cavale spores (e.g., llllldbladispora obsoleta­ lul1atisporifes l10viaulellsis associa tion) to the tri ass ic 140 despi te the fac t that these associations begin in tethys in the undo ubtedly latcs t pe rmian deposits, c.g. in the lower tesero horizon o f the southern alps, with upper dorasham ian conodonts (see below), fusu linids, penni­ an small fo raminifers and perm ian brachi opods. the rev ision of the conodont faunas in the o{oceras beds of g recnl and (s weet , 1976) by re-s tudy of sweet's collection allowed the fe-evaluation of the age of the palynological cvents published by balme (1979). the following success ion of bioevents is present: appear­ ance of "triass ic" sporomorph s end of the mass occurrences of fungal spores fad of 1-1 . parvli s. t he first two events arc w ith in the dorashami an as in the southern alps, and the second event is also recogniz­ able in the uppermost dorashamian of south china. erroneous correlation of the perigondwana and borea l oroceras faunas caused erroneous determination of the ptb in cont inental beds, and erroneous circular conclll ­ s ions, e.g., the "triass ic" age of the boreal otoceras faunas and o f the lower tescro horizon of the southern alps duc to the presence o f "triass ic" sporomorphs. before the rev iew of the conodont and ammonoid data by krystyn & orc hard ( 1996), the erro­ neous placement of the ptb in the arctic was difficult 10 recognize. t here, neither at the base of the o. coj/­ cavum zone nor at the fad of h. parvus nor in any horizon between these biostratigraphic levels, could a disti nct drop in diversity be observed, because a very low-diversity fauna was alread y present before the o. cof/cavuiii zone. th is was because a success ive de­ crease in d iversity occurred by the success ive disap­ pearance or warm-water fau nas, beginning with the dis­ appearance of fusu lin ids at the base o f the middle per­ mi.an (base of guadalupian series). this example clear­ ly ind icates that the permian-triassic biotic crisis was mainly a cris is in the warm-water biota that were restric ted to tcthys at the end of the permian. scveral other problems are re lated to the exaet cor­ rela tion of the pte. strong facies changes from tropical high-dive rsit y shallow-water env ironments to low­ diversity tida l flats a rc always accompanied by a drastic local drop in diversity. if such changes occ ur close to , but no t at the ptb, such fac ies-controlled local di versi­ ty drops have generally been ass igned to the ptb biotic crisis. a good example is the boundary between the bellerophon limestone format ion, with a high-diversi­ ty shal lowwate r fauna , and the lowermost werfcn group (tcsero oolite), wi th a low-diversity intertida l fauna. t his boundary is related to a sea-level drop with­ in the dorashamian. in the eastern part of the southern alps (carn ic alps), thi s sea-ievcl drop caused a sudden shallowing withi n the belle rophon limestone forma­ tion, but the high-diversity permian sha llow-water fau­ na continued. in the wes tern part of the southern alps (dolomites), the same sealevel drop caused in the orig­ inall y shallower depos it s a sudden change from high­ diversit y shallow-water fauna of the bellerophon lime­ stone formation to very low-d iversity fauna of in ter­ tidal ooli tic bcds (tesero ooli te of basa l werfen grogeologia croatica 51/2 up). despite the fact that this drastic diversity drop has noth ing to do with the ptb biotic crisis, but is an int ra­ upper perm ian facies-controlled divers ity drop, it was used as a c lass ical example for the severe ptb exti nc­ tion event. the s it uation in meishan (south ch ina) is different although a ve ry dis tinct dive rs ity drop can al so be observed 18 cm below the fad of 1-1 . parvus, at the base of bed 25. this d iversi ty drop is a real extinction event. it is dist inctl y younger than the be lle rophon limestone formation / werfen group boundary. acco­ rding to the conodont fauna and the distribu tion of the fungal sporcs, this ext inction level somewhat below the ptb corresponds to a leve l approx im ately 2 m above the base of the tesero oolite in the tesero section and within the tesero oolite in other secti ons (c.g., sass de puti a). at this level within the tesero ooli te, the mass occurrence of fungal spores ends (as in pelagic beds at the top of the changxi ng limeslone in meishan a t the top of bed 24), but within a shallow-water upper dora­ shami an conodont fauna wi th hindeodus latidentgtus praeparvlis kozur, isarcicella ?prisca kozur and slepalloviles cf. dobruskinae kozur & pjatako­ va, d istinctly before the fad of h. po/·vlis within the mazzin member. no distinct change in the low-diversi­ ty fauna can be observed at this leve l in the dolomites (southern alps) because the rich perm ian fa una had already d isappeared fo r facia l rcasons at the base of thc tesero oolitc, corresponding to a level w ithin the upper changxing limestone (w ith a diverse dorashamian warm-water fau na) of south china. particu larly in conti nental environments, st rong biot ic changes at the ptb are assumed in sections with a long time-gap between the youngest permian and the oldest triass ic faunas. for instance, between the tatari­ an stage and the lowerm ost triass ic on the russ ian pl atform , there is a long gap that comprises nearly the entire upper pcrm ian loping ian series (kozur, 1989, 1994b, 1998a). desp itc the fact that thc tatarian is mos tly regarded as uppermost permi an, on the russian platfoml (iype tatarian) it ends in different capitan ian to lowermos t dzhulfian levels. there fore , the st rong fau nal changes between the continental tatari an (per­ mian) and vet lugian (t riassic) that were assigned to the exti nction event at the end of the permian, are in reality faunal d ifferences between the middl e permian cap i­ tani an and different leve ls within the lowermost trias­ s ic. therefo re, a summa ry e ffect of la te g uadalupi an and ptb biot ic changes is ass igned to the ptb biot ic cnsls. in dalongkoll (s inki ang), where a continuous, fos­ sil-ri ch seq uence is p resent in the upper permian and lower triassic, the change from the permian to trias­ sic biola occurs in several steps of extinction and inno­ vation that are mai nl y s itu ated wel l below the oldest assumed ptb, the fad of lystrosaurus, at which level no exti nction event in any fa unal or floral group can be observed. even the upper permian vertebrate g uide form , dicynodon, cont inued. a certain extinction event kozu r: problems for evaluation of the scen<lrio of the penn i,m-t riassic boundary ... is indicat ed by the disappearance of dicynodon , in time-correlation close to the fad of h. pan/us, but this extinction is only the final replacement or the permian dicynodon by lystrosaurus that appeared considerably earlier. other permian clements, such as permian fresh­ water gas tropods di sappeared somewhat earlier, but also considerably above the fad of lystrosaurus. rather distinc t changes can be observed consi der­ ably below the fad of lystrosalll'lls. the conchostra­ can genus fa/sisco that straddles the ptb , begins about 96 m below the fad of lystrosaurus. the typical per­ mian conchostraca n genera bipemphigus, megasifll!1l and tripemphigus disappear 65 m below the fad or lystrosaurus. arou nd th is level, a di stinct increase in trile te cavate spores can be observed. il is vely interesting that in the continental biota the "triassic" elements (taxa that straddle the ptb and rep­ resent the lowermost triassic faunas after the extinction of the permian clement s) all beg in within the upper permian , long before the extinction of the permian ele­ ments . thus, the conchostracan fa/sisca appear far below the pad of lys/rosaurus, and aft er the later dis­ appearance of typica l permian genera, a lso dist inctl y below the fad o f lystrosaurus, the generic compos i­ tion of the conehostracan faunas is a lready identical with that of the lowermost triassic. simi lar extinct ion and innovati on pattern s are known among the verte­ brates, where the predominantly triassic lystrosal/rus appeared with in a permian dicynodoll fauna , and the full t riassic character of the vertebrate fauna was estab­ lished by the d isappea rance of dicyl/odoll close to the pte (if deli ned wi th the fad of h. par.,/ls). only detail ed inves ti ga tions of such a co ntinuous rich faunal record across the ptb as in oalongkou can help to understand the extinction and recovery pattcrns of the continen tal faunas. compilations of upper per­ mian and lower triassic cominel1lal faunas with poor stratigraphic control hi nder the eval uat ion o f the biotic changes in the co nt inental upper permi an and lower triassic faunas rather than aid the progression of these studies. 4. problems with the recogn ition of the exact extinction and recovery patterns of major fossil groups close to the ptil interpolati on 0 [" the unknown scythian or lower­ middle scythian diversi ty of many major foss il groups from the known diversity in thc upper permian and anisian in lite rature compilat ions (e.g., erw1n, 1993) is one of the major problems for the eva luation of the causes of the ptb biotic c ri s is. the reco rd of many pelag ic, and also o f shall ow­ wate r marine fauna l g roups in the lower and middl e scythian is vcry poor. a large percentage of taxa tha t di sappeared at the ptb , re-appearcd in the uppcr scy­ thian (upper olenekian) or, more frequently, in the middle triass ic. for several groups the percentage or 141 re-appearing genera (lazarus taxa) is 90-100 %. never­ theless , these form s have not yet been found in the scyth ian or lower-middle scythian, not even in favo ­ urable facies. good examples are the scol ecodonts and the holot hurian sclcrites. scol ecodonts are common in shallow-water, gray or black limestones and shales dur­ ing the upper permian and middle triassic. during the lower triassic, these sediments are widely di stributed , but the examination o f more than 1000 samples in facies favourable for the presence and preservation of scolecodonts has not yie lded any specimens. all upper permi an genera , bar one, re-appear during the ani sian and ladinian. the only genus, de/osites, that does not re-appea r in the midd le triassic, is represented by its immedi ate successor, pa/urites. in the broade r defini ­ tion o f delosiles by z/\ widzka (1971) and kozur ( 1973), both genera are identical. independent of th is special taxonomi c question , the number of triassic scolecodont lazarus genera is 100%, none of the upper permian genera that di sappeared at or somewhat below the ptb , really became extinct. perm ian, middle and upper triassic holothur ian sclerit es are common bot h in s hallow-water and in pelagic deposits. they are especially common in hall ­ statt limestones , mainly reddi sh limestones with a very low sed im entation rate that are o ften stratig raphi cally cond ensed. several hundred scy thian sampl es in the 11105 t favourab le facies for the occurrence and preserva­ ti on o f holothurian sclerites, among them large samples from hall statl limestones, have not y ielded any ho lo­ thurian sclerites. however, in the middle t riass ic, 9 out of 10 genera, which are present in the uppermost per­ mi an, re-appeared in the middle triassic . the onl y upper permian genus, which docs not re-appea r in the middle triassic, is jii i/aealldill(f mostler & rai-il ­ miy azd. however, thi s genus does not occui" in the upper paratiro/ires beds and , therefore, di sa ppeared d istinctly be!"ore the pts (mostler & ra himi ­ y azd, 1976). holothurian sc leriles underwen t a ra ther rap id evolution of the form taxa that can be well rela ted to natural species, and have considerable st rati g raphic import ance in the midd le and upper triass ic (e.g., mostler , 1969, 1973; kozu r & mock , 1974). despite this fact , 6 ollt o f 8 species, which are present in the uppermos t paratiroliles beds, also occ ur in the middle and/or upper t riass ic (mostler & r/\ hi mi­ y azo, 1976). thus, the holo thurian sclc rit es a lso belong to those groups, 01" which 100% of the genera survived the ptb bioti c c ri sis. an interpolati o n of the unknown lower triassic generic diversity of the scolc­ codonts and holothurian sclerites to be constant from the upper perm ian to the base of the lower middle t ri­ assic would be formall y, in a g lobal aspect, co rrect. however, such an in terpre tation wou ld mask the true picture tha t these fossils we re not fou nd in the lowe r triassic even in the most favourablc facies (g ray shal­ low-water limestones for sco lcc oc!onts and redd ish tiall statl limestones for holothurian sclerilcs), despite inves ti ga tion of a large number or samples in different 142 fac ies ancl areas. they have also not been reported by other specialists. thc fact that all eunicida/phy ll odoc ida genera (their isolated jaws are the scolecodonts) and holothuri­ an genera must have survived the ptb does not mean th at they were not affected by the ptb biotic cri sis. they were strong ly affec ted and retreated to current ly unknow n re l ic arcas from where they fe-sett led the middle triassic seas. t hus, even in this case, where the interpolations are formally correct , th ey do not show the real picture of the pte faunal crisis. unfor tunately, in and prior to erwin (i993), the scythian, or at least the lower to middle scythian d iver­ sity patterns of most of the fossi l groups were interpo­ lated from the known upper pennian and middle trias­ sic d iversity. from thi s, a totally incorrect picture of the extinction and recovery patterns for many major fossil groups emerged. on ly in hallam & wignall (i997 ) a correct pic ture o f the extinction and recovery patte rns of some major fossi l groups has been g iven, but no details (amount o f the genera in the different upper permian to middle triassic stages) were prescn­ ted and not all the major fossil groups were considered. nevertheless, the exctinction recovery patterns pre­ sented by hallam & wignall ( 1997) can be used for evaluat ion of the charac ter of the ptb biotic c risis. the exctinction recovery patterns shown by erwin ( 1993) are mostly literature compilations and for most of the major fossil groups are so mi slead ing that they mask rather than highlight the true extinction and reco­ very patte rns. thi s is mainly the result of literature compil ati on and incorrect interpolation of the lower triassic (or lower to middle scythian) diversity. lower scythian divers ity interpolation from known upper permian and middle triassic diversities pro­ duces an espec ially mi sleading picture in those fo ssil groups that have a high upper pennian and middle tri­ ass ic divers ity, but were strong ly affec ted at the ptb (real or large ly real ex tinction, none, very few or a moderate amount of lazarus taxa). in these groups the middl e triass ic high divers ity is not caused by re­ appearance o f lazarus taxa as in the scolecodonts or holothurian sclerites, but by a strong radiation of a very low-diversity fauna which survived the ptb biot ic cri­ sis , or by the new development from skeleton-free rep­ resentatives. a scythian diversity interpolation of these groups shows no pronounced diversity drop at the ptb and a h ig h d ivers ity th roughout the scythian that was not present. two typical examples for a totally incorrect picture of the exctinc ti on recovery patterns of major fossi l groups are d iscussed below. the radiolar ia were shown by er win ( 1993) to have a s li ght d ivers ity drop from 4 to 3 families from the capitanian 10 the dzhulfian, and this level remains constan t unt il the anisian (fig. 2). th is d iversity pat­ tcrn is not only totally outdated, but it is interpolated [or the lower triassic interval, because until recently no radio larians were known from the brahmanian and lowgeologia croatica 51/2 er olenekian. on ly kozur et al. (1996a) described the first known radio larians from this interval. two spec ies of two genera and two fam ilies we re discovered. as these are palaeozoic types, they probably have survived the ptb , but only in the upper olenekian does the diversity o f the radiolarians again become higher. most o f the upper olenekian form s may have evo lved from ske leton-free or simple spicu lar radio larians. t he real diversity pallern of the rad iolarians is shown in fig. 2. there is a strong drop in diversity immed iate ly below the ptb , an extremely low-diversity fauna in the lower and middle scythian (brahmanian = "induan", and in the lower o lenekian), a recovery to near upper permian d iversity in the upper olenekian and lower anisian, and an explosive radiat ion in the middle and upper anisian with a diversity far higher than that of the upper permi ­ an. the picture would be more impressive at genus and species level, but for a comparison to hi ghlight the immense problems that were caused by interpolation of the scythian diversity, the family level has to be used, as erwin ( 1993) used thi s taxonomic level. whereas during the lowe r and middle scythian the number o f' species, genera and fam ilies is the same (2), the number of the dorashamian genera is about 2 times , the number of the upper olenekian genera about 1.4 times, and the number o f the upper anis ian genera about 2.5 times larger than the number of fami lies. dorashamian genera have on average 2-3 species, upper o lenekian genera 12 spec ies and upper anisian 2 spec ies. as i have investigated these rad iolarians by myself, the degree of splitting for the compared radiolarian faunas is the same. the in terpolated pic tu re presented by erwin ( \993) indicates that nothing happened with the silice­ ous plankton at the ptb. in reality, the skeleton-bearing radiolarians nearly di ed o ut , and the production o f organic silica dropped close to zero. even in the pan­ thalassa ocean the lower and middle scyth ian has no radiolari tes, onl y shales that interrupt cont inuous per­ mian to jurassic radiolarite sequences. in this example the interpolation of the diversi ty in the scythi an pre­ sents a totally incorrect picture. a simi lar inco rrect pict ure was presented by er­ win (1993) for the non-fusulinid foram ini fers (fig. 2). also for thi s group, a constantly high divers ity was sho­ wn (l9 families) from the dorashamian to the anisian. in reality, only the upper permian and an isian forami ­ ni fe ral faunas show th is high dive rsity, whereas the brahmani an and lower olenekian foram iniferal faunas have a very low diversity . even considering the fa ct that the anis ian foraminiferal famili es have a high per­ centage of lazarus taxa, there is a very distinct diversi­ ty drop at the ptb. a simila rl y incorrect, and for the lower triassic interpolated scenario, was shown by erwin ( \ 993) fo r the sili ceous sponges (fig . 3). in thi s case, the recon­ st ruction a t family leve l is very diffi cult because the siliceous sponges are mostly not class ified at family level, but in species, genus and order levels. moreover, kozur: problems for evaluation of the scenario of the pennian-tria~s ie boundary ... 30 2520 1510 5y ! ! j ! i i ! ••••••• j' -=., .................. . ! ! .. _.-.. -.-.. _ .. -: .j t ./ , ! t j ! . ! ! ! '.. ! ),.--4/ .----1--7"···" i .... --4 oj---r--',--~--"---~,-,, c a 'c :r 8 c c.-. c c o .q~c 0 0 ·e co 32 .uj !2 ~-a :g ~ -t; ..c c q) !2 0;0 o as ~ o radiolaria diversity lafter erwin) ---.--. uninterpolated d iversity _ ....... _ ... non fusulinid foraminifera diversity (after erwin) ........... uninterpolated diversity 9 143 fig. 2 stage-level capi tania nan isian fam ily di versit y pat­ te rn s o f radi o laria and non­ fusuiinid fonlm inifera after erwin ( 1993) in comparison with not interpolat ed d iversity patterns. the scy thian radio la­ rian famil y di ve rsity patterns by erwi n ( 1993) is clearly int erpo lat ed . and shows no impact of the ptb biotic cr isis on th e dive rsit y o f radio lari a in fami ly leve l. the not inter­ polated family diversity pattern o f radiolaria shows a nearl y compl ete ex ti nction at the ptb, ii beg in ning reco very in the upper olenekian and a st rong rad iati on in the an isian. the di versity pallern of the non -fus­ ul inid foram inifers by erwin ( 1993) fo r the scyth ian part is al so interpolated from the kno­ wn dordsha mi an a nd an isian hig h di ve rsity faunas becau se the di s ti nc t lower and midd le scy thian min imum is mi ss ing. in the lin interpolated div ersity eurve fo r fo ram inifers. the dzhulrian and dorashami an fa ­ m il y di versit y was ove rtaken from er w in ( 1993). because it li es within the error range caused by d ifferent taxonomic scope of the families. the ani­ si an diversity at family level li es below th e upper permian d iversi ty. lazarus taxa are do­ minant in famil y level. the diversity inc rease in fami ly lev­ el from the upper olenekian to anisian is low. but in genus and species level it is high. the strong incre.lse in fami ly level d iversit y from ihe lower to upper olenck ian can be only observed in eastern tethys and open-sea pelagic deposi ts in western tclhys (c. g .• wcstern sicily). in upper olenekian shallow-water deposits of western tethys foramin ife rs are common but have a low di versi ly. most of the taxa in the dorashamian and anisian have to be reconstructed from sponge spicules. thc demospongiae (fig. 3) were shown by erwin ( 1993) to have a very sl ight divers ity drop from the capitan ian to the dzhulfian (from 15 to 14 famili es), thcn a constant family diversity (14 famili es) until the uppermost permian , and an increase to 15 fa milies in ihe " induan", a diversit y that remained constant until the end of the an isian. in reali ty , the demospongiae have a strong d iversity drop from the capitan ian to the dzhu lfian (from 12 to 6 families) and thi s di versity remains constant unt il the top of the dorashamian. they disappeared at the ptb and are not known from the scythi an. they re-appeared in the middle triassic, where their diversity quickly became higher than in the upper permian. there are many lazarus taxa, but sev­ eral groups became ext inct at the ptb. the hexactin elli c1a (fig. 3) are shown by er wi n (1993) to havc a drop in family diversity (6 down to 4 famili es) from the capitanian to the dzhulfian, and this diversity remai ned constant until the end of the anisian. also this diversity pattern is interpolatcd for thc scyth i­ an because in 1993 only one hexaclinellida family (one genus, one speeics rigby & gosney, 1983) was known from the upper scythi an, and on ly kozur et a!. ( 1996a) reported the fi rst siliceous sponge spicules from the upper brahmanian and lower olenekian, which also belong to a single species, perhaps the same species as in the upper olenekian. the real di stribu tion pattern of the hexaeti nellida (based mainly on data of pro f. h. mostler, inns­ bruck, pers . comm.) looks tota ll y d ifferent (fig. 3). there was a drop in diversity from the capitanian to the dzhulfian from 6 to 3 fam ilies tha t continued until the end of the dorashamian (2 fam ilies). there is a very distinct drop in species diversity from the capitanian to the end of the dorashamian (about 70% drop in diversi~ ty), nevertheless, hexactincllida arc still common in the uppermost dorashami an (e.g., in western sic il y kozur & mostler , in prep.). in thc uppcr " lndu­ an" and olenekian , one genus with one spec ies is pre­ sent. in the anisian, the diversity of the hexactinellida 144 geologia croal ica 51n 20 15 .................................................... porifera hexoctinellida diversity (after erwin) ........ --uninterpolated diversity 10 demospongiae diversity (after erwin) fig. 3 stage-level capitan ian to anisian family di versi­ ty patterns of siliceous sponges (demospongiae and hexactinell ida) . com pari son of the di vers ity pat ­ tern s wi th interpo lated scythian dive rsi ty by erwtn ( \993) that show no ptb ex tinction event, with the not intcrpolat cd divers ity pattern that shows the known scythian diversity. inte rrupti on of the curve means that in the scythian no demo­ spongiae and in the lower brahmanian (lower indu­ an) no hexactincllida arc known. this curve shows that the si li ceous sponges have been st rong ly affected by the ptb biotic cr isis and recovered onl y in the middle triassic, wherc many lazarus taxa appeared. " 5 .......•....... uninterpolated d iversity _._.0 c c c c c c 0 0 .q 00 0 .c 'c :g e c 0 :s2 'vi .2 o ::j q) ~ '" 0 ed c '0. n '" q) 0 '" c 0 '" 0= 0 q () 8 io started with low diversity pioneer faunas, and the diver­ s ity rapidly increased within the anisian ( 15 families). there are many lazarus taxa of groups 1hal disappeared a t the end of the permian or earli e r, but because the diversi ty is mostly reconstructed from sponge spicules, it cannot be excluded that some forms arc 1101 lazarus taxa, but homeomorphic forms that newly developed in the middle triassic. in all these cases the diversity drop is far hi gher than indicatcd by erwi n (1993). howcvcr, cxcept for the radiola rians, the number of the laza ru s taxa is rather high, for inslallee, in the siliccous sponges more than 50%. the impo rtan t question is, wh y do they re­ appear only in the uppe r ol enekian , or mostly on ly in the middle triass ic. the above exampl es have shown that interpolation o f the scythian dive rs ity from the upper pe rmian and middle triass ic diversities leads to completely incor­ rect divers ity patte rns across the ptb and in the scyth i­ an. the true di versity pat te rns from the upper perm ian to the middle tri assic show a lot of de tail s of the ex tinc tion and recove ry processes in diffe rent fossil groups. but even true numeric diversity patte rn s are mos tly insuffi c ient to show the real ex tinc tion and recove ry patterns. as most fossil groups comprise a wide variety of taxa adapted to totall y diffe rent fac ies, it is important to s tud y what were the extinction and recovery patterns of different taxa within an investiga­ ted fossil group. forms that li ved in diffe rent environ ­ ments must be separate ly investigated, warm-water ver­ sll s co ld -water taxa, shallowwater versus deep-water taxa, fresh-water versus marine taxa, terrestri al ve rsus aq uatic taxa, light-dependent taxa versus light-independent taxa, taxa that need hi gh oxygen content in the water versus taxa that could live under reduced oxygen content, taxa that lived in the northern hemisphere ver­ sus taxa that lived in the southe rn hemisphere etc. for instance, only warm-wale i' faunas were s trongly affected by the ptb biot ic c ri sis . in the low-diversity boreal faunas no di stin ct ex tinction event can be observed, neither at the base o f the o. col1cavuni zone nor at the much highe r l:;"ad of 1-1. pm'vlts or at any lev­ e l in be tween. an exception is the disappearance of sponge spicules a lilli e below the fad of 1-1. p arlil/s. the boreal land floras and the fun gi were, however, rathe r st rongly affected , e.g., the end of the fun gal mass occurrences somewhat below the fad of i-i. parlilfs. deep-water, cold boltom water, benthi c faun as (palaeopsychrospheric fau nas), investigated mainly among the ostracods (koz ur, 1991 ), arc not g reatly affected , but the upper scythi an and middle triass ic palaeopsychrospheric faunas consis t main ly of lazarus taxa. howeve r, these may not be true lazaru s taxa because no lower and middle scyt hian pajaeopsychro­ spheric os tracod faunas are currently known. li g ht -dependent taxa (coral s, green al gae) were strongly affected, but as they are also warm-water taxa, it is difficult to dccide which factor (light or tempera­ ture changes or both) was dec is ive for the st rong extinc­ tion event among these faunas and no ras. fresh-water faunas with rreeze and/or drought ­ res istant eggs were nol affec ted by the ptb bioti c crisis (e.g., falsisca and euesrheria among the conehos tra­ cans, both present in tcmporary fresh-water lakes of the tropical and boreal real ms). also other fresh-wat er fau ­ nal elements that occur in the pemlian both in the borek07.ur: problems for evaluation of the scenario of the pcnnian-triassic bound;lry ... a l and tropica l realms, were not affected by the ptb (danvil1ula among the ostracods). different aspects of the investigat ion of the ex tinc­ tion-recovery patterns can be well studied in the ostra­ cods because this group has common representat ives in fresh-water and marine, shallow-water and deep-water deposits , warm-water and co ld-water biotopes, and among the ostracods there occur taxa that could li ve only under normal oxygen content and others that could live under reduced oxygcn contents in the sea water. if we compare upper permian with lower to mid­ dle t riassic ostracods as a who le, we cannot find many dilte re nces. the upper permian ostracod faunas are dominated by smooth bairdiacea, such as bairdia , cry­ ptobairdia, bardiacypris, fabalicypris, and in palaeo­ psyehrospheric deep-water ostracod faunas also aca­ thoseapha. the same genera are predominant in the upper scythian and middle triassic ost racod faunas. sculptured ba irdiacea are common in the middle and upper triassic, but some are also present during the upper permian. this minor difference in the bairdi a­ cean fauna is an evolutional)' change. cavellinids (cavel/ ina , sulcel/o) are very common both in upper permian and in triassic ostracod faunas. during the middle triassic transitional forms 10 cythe­ rei/a occu r, but this difference is also a normal evo lu­ ti onary change. kymatophobe ostracod faunas (ostracods that avoid environments with turbulent water movement s), are both in the upper permian and in the middle and upper triassic rich in healdiacea. the permian and lower-middle triassic cyprido­ copina and closely related form s are s imil ar. aeratia, aeratino and microcheilinella are common both in the upper pennian and in the middle-upper triassic. how­ ever, whereas they occur in both deep-water and shal ­ low-water deposits dur ing the late permian , they are restricted to deep-water deposits during the triassic. triassocypris is present both in the upper permian and in the triassic. bashkiring and haworfhino have close­ ly related successors in the lower and middle triassic. the only di stinct difference is the disappearance of praepifatina that is common lip to the top of the penn­ ian. cytherocopina are dominated during the upper per­ mian by bythoey lheraeea and in the palaeopsyehros­ pheric deep-water faunas also by tricorninacea. most or the upper pemlian (and older) bythoeytheraeea gen­ era are al so present in the triassic, such as .iollesia, keijicylhere, nemoceralina, poraberounella and trias­ sacytlle,.e. other upper permian cytheroeopina belong to the youngiellidae, cytherissinellinae and ludahelli­ nae. the youngiellidae end at the pff boundary. in cont rast, most of the cytherissinellinae and ludahe lli ­ nac genera a lso occur in the triassic, such as calfi ­ cythere, .iudahella and gruelldelicythere with the sub­ genus trodoeylhere. only visnyoefla is restricted to the pennian. conseq ucnt ly, the scythian cylherocopina cons ists nearly of the same genera as the upper permi 145 an ones. beginning in the upper scythian and above all in thc middle and upper triass ic, numerous new cyt­ herocopina genera evolved , but this is a normal evolu­ tionary process. except for the above mentioned ostracods, hollinel­ laeea of paleocopida, kloedenell aeea of platyeopida and kirkbyacea of reticulocopida arc common in upper pennian shallow-water deposits. the commonly expressed view that the palaeozoic and triass ic ostra­ cods are very different because paleocopida are present to the top of the permian but absent in the triassic, is not true. firstly, the paleocopida in the upper permian shallow-water deposits are onl y represcnted by the genus /-/ollinella and secondly, this genus is dom inant in lower scyth ian shallow-water deposits. kloedenellacea are vel)' common in the upper per­ mian, but malnly represented by 3 genera of perprim ili­ idae: /-iullgarogeisino, ila logeisina and indivisia . the last two genera are also present in the lower triassic. other kloedenellacea, like pselldobeyrichiopsis, are very rare even in the ex tremely rich upper pe rmian ostracod faunas of hungary. the upper permian kirkbyacea are common and diverse in shallow-water environments. several genera, especially carinaknighfina, continued in the early tri­ assic of peri gondwana and of eastern tethys. within the triassic, they have becn replaced by lypical punci­ acea that evolved from small kirkbyacea, but this tran­ sition had already begun wi th in the late carboniferous­ latc permian time interva l, where such characteristic punci id features evolved, such as the bracket teeth. and nearly all kirkbyacea acquired a calcified inner lamella during the late permian. no distinct changes can be observed within the cladocopida and myodocopida. polycope is common in the upper permian and in the triassic. on ly some, rather rare specialized form s, such as nodopolycope, are restricted to the upper perm ian. even such ostracods that are very rare or not yet known in the permian survived the p(f boundary. the myodocopid cypridinidae that are very rare in the per­ mian became a little more frequent in the triass ic, but no distinct differences betwecn thc permian and trias­ sic form s can be observed. true and defi nitely not reworked "entomozoids" occur in the triassic (koz­ ur, in prep.). paraparchitacea and binodicop ina di sappea red at the permian-triassic boundary, but the upper permian binodicopina are only represented by the rare neoul­ richia . the dorashami ~li1 and lower triass ic fresh water ostracod faunas consist of danvinula. as a whole, the faunal changes between the upper permian and triassic ost racod faunas are insignificant. most of the permian ostracod families and genera sur­ vived into the triassic. however, as shown below, this picture is oversimplified. the upper permian tethyan shallow , warm-water ostracod faunas are very dive rse and cons ist both of 146 " modern forms", like bairdiacea including sculptured bairdiacea, cylherocopina, cypridocopina, and " pala­ eozo ic form s", like pajeocopids, kirkbyaceans, kloe­ dene llids, and cavellinids. in the middle-upper triassic shallow-water ostracod faunas, the "palaeozoic" forms arc no longer present except for com mon transitional forms from cave llinids to cythe rell ids and very rare punc iacca that evo lved from kirkbyacea (kozur, 1998b). however, th is does not mean that the extinc tion of the pa laeozoic forms occurred at the p(f boundary. on the contrary, in the tethyan lower scythian ostracod fauna s the " modern [ofms" a rc missing. these faunas consist mainly of hollillella tillri (patte), somctimes accompanied by a caveltilla or the cavcllinid lallgdaia species and lor an if/divisia species of kloedenellacea. thus, it appea rs that the m ixed palaeozoic-mesozoic tethyan upper pe rm ian sha llow, warm-water fauna is fo llowed by a 100 % palaeozoic fauna. these forms, the cavelli nids, the klocdene llids, but a lso the pa leocopids a re filte r feeders (adamczak, 1969), ab le to live und e r dysaerobic conditions as has been shown for meso-cenozoic fi lter feeder faunas (boomer & whatley, 1992; letl-iiers & w hatley, 1994, 1995; whatley, 1995). th us, if we do not compare the upper permian and the triassic faunas as a whole, but examine in de tail what happened at the p / t boundary, then we can sta te that in the lowermost triassic dysaerobic conditio ns a lso prevai led in shallow-water deposits, as in the wer­ fen fac ies. the re was a kind of superanoxia (isozaki, 1994, 1997), because at this time there were widesprcad anoxic conditions in ocean ic deposi ts tha t rcached to unusually shallow levels. these superanoxia were also de tcjl11ined by evaluation of sedimentological or micro­ fac ial and geoche mi cal criteria (hallam , 1994; ha llam & w ignall, 1997; lai e t a i. , 1996b; wignall & hallam , 1992, 1993; wignall e t ai., 1995, 1996, 1998). they lasted for an unusually long time, in many places throughout the entire lower and midd le scythian (brahmani an = " induan" and low­ er olenekian), in other places only for one or two cono­ dont zones (j-/. parvus or/and i. isarcica zoncs), as in the deep-water deposits in sicily. in the upper scythian and middle triassic, the typi­ cal palaeozoic, low-diversity fauna recovered first , with the re -a ppea rance of ilumerous lazarus taxa in the upper scythian. nearl y all taxa that disappeared at the ptb, re-appeared in this levcl (scc above). at the same time, the j-iollinacea and kloedenellacea became extinct in s hallow mari ne fauna s. only a few kloedenellacea survived in upper scyth ian brackish environments, but became extinct in thi s fac ies at the end of the scyth ian. this ex tinction-recovery pattern can be found in all shal low marine, warm-water fauna s of te thys, from westernmost tethys (kozur, 1985) to easte rnm os t tet hys (c.g., wang & wang, 1997). however, the borea l and pcrigondwana ostracod fauna s show a dif­ ferent ex tinction pattern at the ptb. in the boreal realm bo th the upper permian and lower triassic ostracod geologia croatica 51/2 fa unas have a very low divers it y, and no obviou s changes occur a t the ptb , wherever it is placed. in pcrigondwana, there is also no d istinct extinction event in the os tracod faunas at the ptb. both in the upper­ most permian and in the lower t riass ic a moderate ly diverse temperate-water ostracod fauna is present. it contains common, but low-divers ity kirkbyacea (main­ ly carinaknighfina and other sma ll form s, bu t mainly with othe r spec ies as in tethys), ve ry low-di vers ity bairdiacea without the tropica l scu lptured ba irdiacea, ve ry low-d ive rsity cypridocopin a (microche itill ella), low divcrs ity cythe rocopin a, and a few cavell inidae (sohn, 1970). the hollinella-eave llini d-k loedene llid boom of the lowermost t riassic of tethys is miss ing. if we look the furthe r differences to the tropical t e thys both in the uppemlost perm ian and in the lower trias­ sic, then we can state that the uppermost permian fauna is a cool-temperate fau na o f moderate diversit y, in which all the tropical forms, such as sculptured bair­ d iacea, strongly sculptured representati ves o f kirkby­ acea and kloedene ll acea a re missing. moreover, the s trong anoxic event in the i-i. par viis and t. i.wrcica zoncs is missing. instead, the anoxia began immed iately above the i. ism'ciea zone (wignall e t ai., 1996). the differences in th e faunas be tween peri gondwana and the tethys (cool-temperate versus tropica l) and the dist inctly latc r beg inning of the s trong anox ia in peri­ go ndwana compared with the tropical t et hys a ll ow testing of whether the anoxia were e ither d ircctly respons ib le fo r the ptb ex tinct ion (hallam , 1994; hallam & wignall, 1997; wignall & hal­ lam , 1992, 1993; wignall ct a l. , 1995, 1996, 1998) or only indirectly (by preventing the rapid recovery of the tet hyan warm -watcr fauna), and the assumed vol­ canic winte r had the main ki lli ng effect on the tethyan warm-watcr faunas (kozur, 1994a, i 996b, c, d , 1997b, c). t he moderate diverse peri gondwana cool-tcmperatc ostracod fauna straddles the ptb wit hout distinct changes. thi s could be due to the fac t that the non-trop­ ical ostracod fauna was unharmed by thc short-last ing volcanic win ter (the expected response of a cool-tem­ perate fauna to a three six month pe ri od of coo ling). an other explanation may be the absencc of anoxia in the peri gondwana h. parvlis and t. isarc ica zones. i iowcver, th is ostracod fauna also straddles the onset of thc anoxia above the f. isarcica zonc. for example, the same kirkbyacea as in the uppermost permian are com­ mon in the lower mittiwali membe r of the mianwal i format ion (sohn, 1970), whereas the change to dys­ acrobic cond itions had a lrcady occurred wit hin thc upper part of the underlying kathwai member (w ig ­ nall et al., 1996). there is some ext inction connected wi th the begi nning of the anoxia (ma in ext inct ion hori ­ zon in wignall et ai., 1996), but the divers ity drop in the macrofauna at thc tran siti on from highly oxy­ genated sha llow-watcr to more basinal, poor oxygena­ tcd dcposits is a normal rcaction to such a facies change independent of the strat igraph ic level in which thi s kozur: problems for evatu:liion of the scenario of the pcnnian~trias.~ ic boundary ... faci es change occurred, and unrelated to a mass ex tinc­ tion even t. this is best proven by the fac t that the same react ion to this facies change is found in perigondwana at diffcrent levels (w ignall et ai. , 1996). it occu rs sooner, where the anoxia began earlier (kashmir) and later, where the anoxia began later (sail range). this may produce a local or regional, but not a global low­ divers ity fauna and flora , and no world-wide mass extinction. therefore, even the sllpe ranoxia does not have a global killing cffeet on the tropical warm-water fauna, and it cannot affect the fauna and flora of the upper 10-20 m of the water column of the entire tropi­ cal tethyan realm. however, this fauna and flora (green algae, reef community and other warm-water, shallow­ wate r faunas) were the most strongly affected by the ptb biotic crisis. the third type of change in the ostracod faunas was discovercd by hao ( 1992) in guizhou, in the central part of eastern tethys. as in the entire tethyan realm , the upper permian ostracod faun a is a highly diverse fauna, consisting of " modern" and palaeozoic types (see above). the southern part of the inner eastern tethys should be thc least influenced by a killing effect of the volcan ic winter because it was further away from the huge volcanic emption center close to the northeast­ ern end of eastern tethys (at the transition to panthalas­ sa), and it was close to the tropical panthalassa, where obviously most of thc lazarus taxa of the uppcr pemli­ an shallow, warm-water fauna survi ved the ptb biotic crisis. as expected, this is the case despite the fact that the anoxic event in the h. pm·vlls zone is very pro­ nounced. the latter is indicated by the booming of hollillella and langdaia. however, in the guizhou fau­ na some of those ostracods are also present which dis­ appear in most tethyan warm-water faunas at the ptb, including aci·aria, faba/icypris, "paraeypris" and 8a­ shkirillo (t he first three forms re-appear in the upper scyt hian or middle triassic, whereas instead of bashki­ rilla the closely related successor spinocypris appears in thc lipper scythian). also the kirkbyid carinaknig/rl­ ina is common in the h. parvus zone. the inner eastern tethyan area was therefore either close to or a part of the refuge for the upper permian shallow, warm-water benth ic ostracods. the ex tinction recovery patterns of the ostracods yield many important data, including: the presence of pronounced anoxia in the tethyan lower scythian which reached to an unusually high level in the water col umn ; the clear evidence that the killing effect at the ptb was caused by a temperature drop and not by the beginning of the anoxia; and sugges tions, that the refu­ ge of the numerous lazarus taxa that re-appeared in the upper scythian and middle triassic may have been sit­ uated in shallow-water areas in the tropical part of large oceans, such as panthalassa and perhaps also in the southern part of eastern tethys. to obtain these results however, it was necessary not to make any interpola­ tions of the scythian diversity, and in contras t, the divers ity recovery patterns in different areas, and \47 above all climatic zones, must be regarded separately. another, not so serious problem for most groups, is the c laborat ion of thc diversit y patterns at a too high taxonomic category. often the diversity pattenls of dif­ ferent groups are show n for the family leve l (e.g ., erwin, 1993) because most authors work exclusively with data compiled from the literature and not with their own results from the study of a major fossil group. for many groups, the diversi ty patterns at famil y level show a fai rly good picture of the extinct ion and recov­ ery patterns around the ptb, but generally at genus lev­ el the result s are more reliable. however, there are some groups, e .g., the conodont s, for which only the species level shows the impact of the ptb biotic crisis. the conodonts show no diversity drop at genus lev­ el around the ptb. this lead to thc rcpcatedly exp­ ressed assumption "that conodonts were almost unaf­ fec ted by the p-t exti nction" (hoffmann ct ai., 1998). this, howevcr, is not correct. at species level, there is a distinct low diversity interval in the latest per­ mian and in the lower fi ve triassic conodont zones with two minima in the h. parvlls zone and in the s. kum­ meli and lower n. di ener; zones. however. even the study of the conodont diversity at species level around the ptb gives an incorrect picture because among the conodonts the warm-water species (in the dorashamian restricted to the tropical tethyan area) and cool-water species (in the boreal realm and at the peri gondwana shelf as well as in cold bottom-water in the tethys) were affccted in different manner by the ptb biotic cri­ sis. whereas the warm-water restricted clarkina sub­ carinara group disappeared at the end of the permian , the cold-water adaptcd hindeodlls iypicalis and clarki­ na caril/ara lineages nourished , with distinct diversifi­ cation and occupation of the tethyan biotopes after the di sappearance of the warm-water forms. therefore, a total turnove r of the conodont faun as occurred at the end of the permian , but because the diversification of the cool-water elements (s tarted at the base of the i. iso/dea zone) occurred only a little after the extinction of the warm-water form s (mainly at thc base and part ly at the top of the las t permian conodont zone, thc c. meishal1ellsis i-i . la tidelltaflls praeparvf{s zone), the di vers ity drop in species level was not very significant. at the top of thc gangetian substage (top of the h. postparvus h. sosioensis zone;::; top of the c. carina!a interv al zone), all hindeodid conodonts disappcarcd and the c. carinala group became very rare_ at this second pronounced ex tinction event in the conodont fauna , on ly the cool-water conodonts that survi ved the mass ex tinction in the uppermost pe rmi an and flour­ ished in the lower three triassic conodont zones were affected. somewhat later a strong diversification of tethyan warm-water conodonts began that also invaded the boreal rcalm. the disappearancc of the hindeodid conodonts especially indicates an important change in the conodont fauna , as this group had , in the lowermost triassic, its strongest diversification and widest regio­ nal and facial distribution of its late palaeozoic to ear148 lies t triassic history . with the disappearance of this group, the mixed palaeozoic-triassic conodont fauna of the earliest triassic was replaced by a low-diversity triassic conodont fauna. thus, detailed conodont studies show that the con­ odonts were strong ly affected by the ptb biotic crisis. at first the late penniao wann-water conodonts totally disappeared in the lates t permian, and three conodont zones later the cool-water conodonts disappeared almost totally. this extinction pattern yie lds important data for the causes of the ptb biotic crisis : a drastic drop in the temperature in low latitudes during the uppermost pennian that coincided with a huge volcanic fallout in eastern tethys (46 cm dust tuff over an area of 2 million km' ) and a strong global warming three conodont zones later. s. some remarks on the abiotic indicators of the ptb biotic crisis there are no indications of an impact of a large extraterrestrial body (no iridium peak) close to the ptb (y in & zhang, 1996). however, a lillie below the ptb an enrichment of microspherules can be fou nd (japan, china , hungary). in mei shan , south china, they occur in boundary beds i, at the level of a sharp drop in fau nal diversity. according to yin & zhang ( 1996), they are e ither of extraterrestrial or of volcanic orig in , and the si liceous microspherules are s imilar to ihose found in the plume of the ml. etna volcano. as these microspherules occur both in an al tered volcanic du st layer (bed 25) and in an overlying anoxic layer (bed 26), they may be of both volcanic and extraterres­ trial origin. in the bukk mts . of hungary , a few cen­ timetre thick microspheruie layer occurs about one metre above the top of the nagyv isny6 formation (equivalent of the bellerophon limestone formation of ihe southern alps), in the basal werfen group with a low diversity lates t pennian fauna, a few meters below ihe fad of h. parvlls. the big faunal drop occurs at the top of the nagyvi sny6 formation , but may be facies­ coni rolled. according to detre et al. ( 1998), the microspherules of this horizon are of ex trate rrestrial origi n. this horizon may be contemporaneous wi th the boundary bed i , because the sedimentat ion rate in the bukk mts. was high, whereas the boundary beds of mei shan are strongly condensed. both horizons are above the lad of fu sulinids and a diverse permian fau ­ na and below th e fad of h. parvli s. accordi ng to detre et al. ( 1998), these interstellar microspherules arc related to a supernova explos ion close to the solar system (wi thin a d isiance of 20 pc). although this assumption is not proven, some aspects of the calcula­ ted effects of a supernova explosion c lose to the solar system (depletion of ihe ozone layer, cooling of the tro­ posphere) were probably present with in the uppermost permi an , but thi s can a lso be explai ned by huge vol­ canic eruptions that caused a volcanic winter (kozur, geologia croot ica 51(1. 1998a). the explanation of the anoxia and increase in co, by the high amount of dead biomass due to the mass extinction (detre e t ai., 1998) is sure ly incor­ reel. nevertheless, the possible effects of a supernova explosion on the earth's biota should be taken into seri­ ous consideration, especially from the astronomy point of view: can the gamma and roentgen radiation and lat­ er the corpuscular radiation and much later expanding gas and dust (as the assumed source of the microsphe­ rul es) from a supernova exp losion close to the sun (within a distance of 20 or even of 10 pc) harm the earth' s biota despite the protection by solar wind, earth 's atmosphere and magnetic field? regardless of the inte rste llar or volcanic source, a thin horizon of strong enrichment of microspherules a linle be low the ptb could be a good auxilliary marker for the base of the triassic , if it wi ll be di scovered in the same level in other and distant well datable sec tions (e.g. in nw and central iran). terres trial causes for the ptb biotic crisis are pre­ fe rred. they may be a lso indicated by geochemica l changes. geochemical evidence, mainly changes in the ratios of stable isotopes are commonly used as indica­ tors for the ptb biotic crisis (013c) or for environmen­ tal or climatic changes (8"0, 8" s, " sr/" sr). wang et al. ( 1994) allributed the drop in 8 " c to a catastrophic coll apse of the marine primary productivity at the base of the triassic. a produc tivity drop may contribute to the drop in 8" c, but there a re several other factors (d ia­ genesis, dolomitization, sed iment alteration by subaeri ­ a l exposure connected with a gap, oceanic anoxia) that influence the 0 13c curve as discussed in kozur (i 998a). for instance , in ih e se long section (tibe t) , there is a strong negative shift of the odc curve at a caliche bed (yin et ai., i 996b) that is underand over­ lain by beds with gudadalupian cool-water conodonts, whereas no minimum in the oilc occurs in the basal t riassic. for this reason, the caliche bed was regarded as an equivalent of the boundary clay immediatcely below the ptb in south chin a (w ang et a i. , 1989; m el , 1996). the strong drop of b"c reported by wang ef al. (1994) from brit ish columbia may also be caused by sediment altera ti on during a long gap. nevertheless, in many sections a primary minimum in the ouc curve is present at the very base of the triass ic. however, it is not certain that this drop depends on the drop in bioproductivity a lo ne, or on other factors as well (or sometimes excl usive ly on the above menti oned other factors foster, 1997; kozur, [998a). at lhe guadaju pian lopingian boundary, where there is a strong drop in bioproducti vity, the 013e curve does not d rop but it may even rise s lig htly (holser e l a i. , 1991). the possi bility for slrat igraphic mis inte rpreta ­ ti on is much higher [or the onset of the drop in the 013c curve, or for its minimum, than for the biostratigraphi­ cally defined base of the triassic (shortly discussed in secti on 2). therefore, the proposal to use th e carbon isotope shift fo r the exact defin ition of the base of the triass ic (newell, 1994: minimum of the 8"c curve kozur: problems for evaluation of the scenario of the pennian-triassic boundary ... as base of the triassic; hoffmann et ai. , 1998: onset of the drop in the 8"c curve near the ptb as base of the triassic) cannot be supported. moreover, detailed investigations have shown that there are often two min­ ima of sim ilar magnitude of the ol3e curve in somewhat different stratigraphic levels, which excludes the use of the minimum of the ode curve for definit ion of the base of the triassic. the lower minimum lies in differ­ ent sections somewhat below, at or somewhat above the fad of h. parvus. the onset of the drop in the 8 " c curve lies in the undoubtedly permian clarkina chang­ xing ensis c. de/leela zone. this was also stated by hoffmann et al. (1998), but explained that the con­ odonts are almost unaffected by the ptb ext inct ion event, which is not the case because the warm-water conodont fa unas disappeared. however, in the leve l, where the onset of the drop in the odc curve occurs, there is not only a typical permian conodont fauna, in tethys dom inated by warm-water species of clarkina , but also a typ ical permian pseudoliro/iles ammonoid fauna, a typical perm ian foraminiferal fauna with latest fusulinids, typical permian brachiopod, radiolarian and sponge faunas. the carbon isotope shift yields only auxiliary data for the definition of the base of the trias­ sic which are neither as precise and invariably fixed to a precise time level nor situated at the level of the mass extinction or at the level of the appearance of the first triassic foss ils after the mass extinction. a pronounced negati ve shift of 8" c in the lower­ most triassic lies distinctly above the strong divers ity drop close to the ptb, and was therefore not connected to the fac tors that caused this diversity drop (kozur, 1998a). also the strong increase in 8" s during the scy­ th ian is obviously not re lated to any environmental change in connection with the ptb biotic crisis. 6. dating and complex evaluation of the effects of the extremely strong volcanic activity in the upper permian and lowermost triassic there is a perfect time correlation between the ptb biotic crisis and the strongest volcanism in phanerozoic history. as shown by kozur ( 1998a), this volcanism had both direct effects, such as acid rain and a short volcani c wi nter, and indirect effects, including strong uv radiation as a result of the destruction of the ozone layer by an extremely strong eruption, and the onset of superanoxia, as well as combined direct and indirect effects, such as climatic changes. the extremely strong volcanism was obviously the most im portant factor of the ptb biot ic crisis. 6.1. dating ofth e volcanism and its effects during the volcanic activity the effects of the volcanic activi ty on the biotic divers ity around the ptb can only be estimated by very complex studies. first of all , the very exact dating of all \49 occurrences is necessary to show whether volcanics, especially tuffs, are exactly contemporaneous over a large area and fit into the time interval of the biotic changes. this dating is easy and undi sputed for the tuffs that belong to a volcanic centre s ituated at the northeastern margin of the eastern tethys adjacent to panthalassa. in south china, very fine -grained altered tuffs of felsicintermediate composition, with a constant thickness of around 6 cm can be found in the uppermost dorashamian in all sections, where the deposition was below the storm-wave base. they are best investigated in the meishan section (zhejiang province) and in the shangsi section (sichuan province), about 1500 km to the west of meishan (for details and complete refe­ rences see yin et ai., 1996 and lai et ai. , 1996). fur­ ther tuff layers of the same chemical composition are present within the upper dorashamian and in the lower­ most triassic. the tuff layer a few centimetres below the fad of h. parv"s is connected with the stronges t exti nction event, but some of the other tuff layers are also connected with extinctions. the northernmost kno­ wn occurrence of tuffs of an upper dorashamian explo­ s ive fel sic-intermediate volcanism is in se siberia, about 2000 km ne of meishan (zakharov et ai. , 1995). there, about 65 m of tuffitic layers is present, but with sedimentary intercalations; nevertheless the thickness of the upper dorasham ian volcanics is there much larger than in south china. the se-s iberian occurrences were obviously closer to the eruption cen­ tres that were situated at the margin of panthalassa, close to the northeastern margin of eastern tethys. the south chi nese altered tu ff layers are so fine-grained and thei r thickness is so constant over huge distances (about 2 million krn') that they may be part ly related to a fall -out of aerosol du st. this huge explosive fe lsie­ intermediate volcanism probably caused a volcanic winter in the uppermost permian. the palaeolatitude of the eruption centre was in low northern latitudes. the­ refore, the effects of the volcanic winter and of the reduction of sunlight should be strongest in the low northern latitudes that correspond to a large part of the tethys , to which the lates t permian shallow warm­ water benthos was restricted (except for insular occur­ rences in the tropical part of panthalassa). only the southern part of eastern tethys (with the perigondwana margin) was situated in low to middl e southern lati ­ tudes. thi s part of southern tethys , and above all the insular areas within tropical panthalassa, had the great­ est potential as a refuge for the shallow warm-water benthos. the age of the siberian trap was disputed for a long time. regarding its post-tatarian age, dobruskina & mogutcheva ( 1987) assigned it to the triassic. in this case, the siberian trap would be without any importance for the ptb biotic crisis. sadovnikov & orlova (1994) and sadovnikov (1997) ass i­ gned the larges t part of the siberian trap to the post­ tatarian , bu t late permian taimyrian stage. the con­ chostracans and the new radiometric data fu lly confinn 150 the posi-tatarian late permian age [or mos t of the siberian trap. the predominantly tuffitic hungtukun­ skian format ion of the tungusska basin conta ins fa/­ sisco species (post-tatarian conchostracan genus) that arc present in the dalongkou sect ion cons iderable be low thc fad of lystrosaurus , and disappear 54 m bclow the fad of lystrosaurus in undoubtedly upper, but not thc uppermost permian beds. the followin g puluranian basalt and related intrusives have. according to renne et al. (1995), an age of 250 (± 1.6) ma. bed 25 in the meishan section, 14-18 cm below the base of the triassic detined by the fad of h. parvus was dated by thc samc authors as 249.98 (± 0.20) ma. thc puill ­ fanian basalt started, therefore, somewhat before the ptb and straddled thi s boundary. the s iberian trap covers 2.5 million km:'! , however, it is probably that in the subsurface of western siberia, under a thick meso­ cenozoic cover, large areas arc also covered by the siberian trap, as the westernmost occurrence of the trap basalts is in the urals. thus, the area covered by the siberian trap may be fa r larger than 2.5 millio n km 2 , but a lready this area covered by thi ck tu ff layers followed by oood basalt indicates the greatest vol canic activity in the phanerozoic. the int ra-basalt ic layers of the urals as the western­ most ext ension of the s iberian trap volcanism were dated by tuzhikova (1985) as lowermost triass ic and would there fore post-date the ptb bioli c c ri s is. kozur ( 1989) agreed with tuzhikov a ( 1985) that the intra-basaltic layers of the urals are post-tatarian , but he pointed out that they are upper permian. a large part of the zechstein pal ynodemes di scrimi nated by v1ssher ( 197 1) occur in the intra-basaltic layers that correspond therefore to parl of the undoubtedly pemli­ an zechstein . immediately below the lower volcanics, and in the lower part of the intra-basalti c sediment s, lueckisporites virkkiae potonie & klaus , mainly norm ae, is common (up to 16% of the sporomo rphs). thi s part of the sequence is not younger than the asso­ ciation with dominating l. virkkiae norm ac scnsu v1ssh er that corresponds to the upper zechstein 3. in the younger part of the intra-basaltic sediments luecki­ spar/res cr. parvll s klaus (:::: l. virkkiae, norm bc according to viss her, 1971) becomes dominant and then gul!lillapollenites sp. (l. virkkiae, norm c sensu viss i-ier , 197 1) becomes increasingly frequent. acco­ rd ing to the corre lation of the zechstein sporomorph assoc ia tions with the international scale (kozur, 1994b), the post-tatarian intra-basaltic beds are upper dzhulfi an to lower dorashamian. the followi ng mai n phase of the volcanism began in the upper dorashamian and las ted until the lowermost triassic (gangetian sub­ stage). it straddles, therefore, the ptb. the two, close to the ptb contemporaneously acti ­ ve volcanic centres (siberian trap volcani sm and huge expl os ive volcanism at the northern tethys/panthalassa transition) , had surely a strong injluencc on the world clim ate. howeve r, there arc also other areas with tuffs and lavas close to the ptb. dr. spencer lucas , albugeolog ia croatica 5 1/2 querque, found altered tuff layers c lose to the ptb at the dalongkou section in sinkiang. unfortunately, the material was confiscated and there fore neither radio­ metric nor geochemical investigations cou ld be carried out. if these volcanics are re lated either to the siberian trap or to the volcan ic centre at the transition between the northeastern tethys and panthalassa , thi s wou ld very much enlarge the areas with volcanic ashes or dust fall -out of one of these two volcanic centres. but even if they would belong to an independent volcanic centre, thi s would further enlarge th e areas a ffec ted in the uppermost dorashamian by volcanic fall -out. accord ing to kozur (1998a) , the long-lasting, ini­ tially mainly explosive siberi an trap volcanism (very intense from the uppermost dzhulfian to lowermost triass ic) caused some cli matic changes that harmed especially the terrestrial biola (severe climate, cooling in high and medium lat itudes, ac id rain). during this time, the tropical warm-wate r fau nas re trea ted to the tropical tethys. thus, in the med ium-lati tude perigond­ wan a sa lt range, the dzhul fian is charac terized by tethyan wann-water conodonts. in the upperm ost dzh­ ulfian and lowermost dorashamian they were replaced by cool-water conodonts. the area with tropi cal warm ­ water faunas became in the dorashami an very narrow and was restricted to the central and nort hern tethys, where they remained highly diverse, and insular regions in the equatorial panthalassa. the huge explosive felsic-intennediatc vo lcanism at the northeastern margin of tethys a little be low the ptb caused according to kozur ( 1998a), a 3 6 month volcanic winter in low lati tudes. t his period was long enough 10 kill the trop ica l warm-water faun as on the tethyan shelves, but not long enough to bring the water temperature below the critical water-temperature for tropical warm -water faunas on the shelves of insular regions in the tropical part of panthal ass a. t here, a large part of the warm-water faun as survived the ptb biotic crisis, and re-appeared on the tethyan shelves in the upper olenekian and in the middle triass ic as lazarus taxa. a "side effect" of the huge volcani c eruption in the uppermost permian that caused the volcanic winter, ill ay be the destruction of the ozone layer by an espe­ ci a ll y violent e ruption. aeroso ls and gases o f a huge explos ive e ruption could reach the ozone layer and deplete it. the consequence would be strong uv rad ia­ tion. the sudden di sappearance of the worldwide mass occurrences of fun g i cxactl y at the level of the huge volcanic erupt ion at the northeastern marg in o r tethys is best explained by strong u v radi at ion that is lethal for fungi. s trong ly reduced sun light would favour rat­ her than harm the growth of fungi and also the cooling in a volcanic winter would not hann the tympallocysta fun gal ass ociation becau se it is comm on both in th e tropi cal tethyan and in the cold bo rea l rea lm, and therefore adapted to both warm and cold climates. the biot ic express ions for a cooling event arc obvi­ ous (koz ur , 1998a). mainl y the tro pi cal shall ow, kozur; problems for evaluation oflhe scenario of fhe pennian-triassic boundary .. . warm-water fauna and flora as well as the plankton were affected by ihe ptb biotic cri s is. the plankl on mass ext inction may also be re lated to a time of redu­ ced sunlight that would accompany a volcanic winter, and the radiolarian ext inct ion is probably partly related to oceani c anoxia. the mass extinct ion of tropical shal­ low-water biota could have been caused by a strong low latitude cooling or warming (the latte r is favoured by hallam & wignall, 1997, for the lropical areas), bui accord ing to kozur (l998a) a strong warming in low la titudes during the uppermost permian can be excluded (st rong extinct ion of warm-water fa unas, but no pronounced extinction of marine cold!cool-water faunas and no cont inental extinction event in that strat i­ graphic level, contemporaneous equator-ward migrat ion of high latitude cool/cold-water faunas). moreover, the strong g lobal warming al ihe base of the gandarian (= base of dienerian) post-dates the ptb extinction event except the delayed extinct ion event of cool-water con· odonts. this global warming is directly related to the volcanic winter and the foregoing long· lasting siberian trap volcanism (see below). the important question is why the warm-water fau ­ nas from the tropical panthalassa cou ld not return to tethys earl ier. a vo lcanic winter, accompanied by a strong reduct ion of sunli ght, and the beg inning of the longlasting, strong and violent siberian trap vo lca­ nism within the dzhult1an (with the culmina tion of the volcanic activity in the upper dorashamian and lower­ most triassic) perfectly explain the observed extinction pattern affecting mainly the terrestrial communit ies (earlier than the marine faunas), the plankton, and the trop ical shallow, warm-water faunas. however, this event alone can not explain that the recovery occurred only in ihe upper scythian (upper olenckian) and mid­ dle t riass ic, several million years after the ptb biotic crisis. after the end of the volcanic winter, the tropical shelf communities wou ld recovt?r very fast by migration of warm-water faunas that had survived on the shelves of intra-oceanic islands (see above). both the extinction on the tropical shelves and the recovery of the tropical warm-water biota would happen in geologically a very short time. in the geological record on ly a modera te ex tinction event and innovations of new faunal cle­ ments would be observed. this can be, for instance, observed after the midd le carnian disappearance of the tet hyan reef communi ties. 6.2. delayed effects of the very intense volcanism after the end of the vol­ canic winter and after the end ofth e sib erian trap volcanism the reason for the long delay in the recovery of the wann·water benthos on the tethyan shelves was the oceanic superanox ia which reached an unusually high level in the water column (e.g., as shown by dysaerobic conditions in the mazzin member and similar shallow­ water depos its above the storm -wave base, and black lsi shales in all oceans). the recovery of the tethyan warm-water faunas coincides with the end of the long­ lasting lower-middle scyth ian oceani c superanoxia in the sense of isozaki ( 1994, 1997). as these superanoxia reached a leve l above the storm-wave base, they were an effect ive barrier against the migration of the warm -water benthos that had sur­ vived on the shelves around oceanic islands in the tropi­ cal panthalassa (and perhaps partly also within eastern tethys) to the tropical tcthyan shelves. moreover, such superanox ia also prevented the recovery of those radio­ larians (plankton) that lived benealh the uppermost, oxygenated water column . thus, only the phytoplank­ ton (e.g. , acritarchs), whi ch occur in the uppermos t oceanic layer, recovered quickly after the volcanic win­ tcr (and the accompanyi ng slrongly reduced sunlight). the superanoxia were probably tr iggered by the unique volcanic activity in the dzhulfian to lowermost scythian in terval. the huge amounts of dust and sul­ phate aerosols caused strong precipitat ion in areas that were normally dry, both in the low and high latitude dry belts. as a result large inputs of fresh-water occurred in the high latitude cold seas, and this causcd a decrease in densi ty of the heavy cold surface water. the si nking of heavy cold surface water strongly dec reased or even ceased. t his down-s inking of heavy, cold surface water in the high latitudes is, however, the "motor" for the cold bottom water currents that bring highly oxygena­ ted co ld surface wate r v ia deep-water currents in the tropica l oceans, from where warm surface currents transport warm-water into high latitudes. if this oceanic current system di sappeared or became very weak, oce­ anic anoxia were established. t he lengthy dura tion of the oceanic anox ia was caused by a strong g lobal warming at the base of ihe gandarian (= dicnerian) indicated by ihe appearance of tethyan warm-water biota in unusual high latitudes , such as spitsbergen (wignall et a i. , 1998; kozur, 1998a). this caused a globally rather uniform cl imale during the upper brahmanian (gandarian substage ;;;; dienerian) , indicated by world-wide rather unifonn fau­ nas (e.g., claraia faunas), and a low temperature gradi­ ent in the tethyan and boreal oceans, that for a lon g period prevented ihe re-establishment of the cold bot ­ tom water currents. the temperature g radient between the telhyan and boreal rea lm became higher again dur­ ing the lower oleneki an as indicated by increasing fau­ nal differences between these realms. the upper bound­ ary of the oceanic anox ia became lower during that time, but at least pan tha lassa remained anoxic. in the upper olenekian the co ld bottom-water currents were re-estab lished as indicated by the re-appearance of cold bottom-water palaeopsychrospheri c ostracod fauna s in tethys. contemporaneous ly, numerous lazarus taxa among the shallow-water warm-water benthos migrated from their insular shelf relic areas withi n panthal assa in to tethys. the strong global warming at the base of the gai1darian (= dienerian) was also caused by the volcan ic 152 winter and the lengthy period of siberian trap volcan­ ism. the very strong explosive volcanism that caused the volcanic winter, and the foregoing as well as con­ temporaneous siberian trap produced huge amounts of the greenhouse gas co2 • as mentioned above, the huge amounts of dust and sulphate aerosols that caused a vol­ canic winter favoured strong precipitation also in the dry hi gh latitude and in the arid low latitude girdles. the strong precipitations in the normally arid low lati­ tude gi rdles caused a strong increase in the total amount of water vapour in the earth's atmosphere. as water vapour is an effective greenhouse gas, this caused an additional strong greenhouse effect. as long as the siberian trap volcanism continued, this greenhouse effect was counterbalanced by dust and sulphate aero­ sols. however, the siberian trap volcanism ended dur­ ing the upper gangetian, or at the latest by the top of the gangetian because overlying sediments both in the tungusska basin and in the urals yielded cornia rer­ mari (beyrich) and other vertexiids that are guide forms of the gandarian. after the end of the siberian trap volcanism the greenhouse effect resulted in a strong global warming that may have been as high as 6°c on average. as assumed by hallam & wig­ nall (1997). the high precipitation, also in the formerly dry low and high latitude girdle, is an assumption (based on knowledge about the huge explosive volcanic activity in the upper permian and especially around the ptb) that needs to be verified by geological and geochemical data. the strong increase in precipitation in the upper dorashamian and lower scythian may have caused (at least partly) the significant increase in the 87sr/86sr ratio that indicates a large increase in chemical weath­ ering triggered by increased humidity and atmospheric co2 levels. it is striking that in the uppermost dora­ sham ian and in the h. parvus and 1. isareiea zones of the lowermost scythian, no signs of hypersaline seas or continental arid climate can be found globally, not even in areas that were previously very arid, as in the ger­ mani c basin or the alps. in the germanic basin, the hypersaline sedimentation and salt precipitation in the zechstein ended in the central basin and large fre sh water lakes with charophytes, darwinula and conchos­ tracans developed, whereas in the marginal part arid desert or sabkha cond itions were replaced by fluviatile conditi ons. thus, the predicted time interval of high precipitation in the normally arid low and high latitude girdles was really present during the uppermost dorashamian c. meishanensis h. latidentatus prae­ parvus zone (starting with the very intense explosive eruption at the northeastern margin of the tethys) and lowermost triassk h. parvlls and 1. isarciea zones. above the 1. isareica zone the climate fluctuated rapidly. in the red upper sandy claystone member of the calvorde formation and in the contemporaneous andraz hori zon of the southern alps, the climate again bccame ar id in the low latitude dry girdles. in the upper calvo rde formation and bernburg formation (except geologia croatica 51!2 for its uppermost part), and in the contemporaneous seis member of the alps and hungary, a rapid fluctua­ tion of predominantly humid to semi-humid with semi­ arid to arid climate can be observed. in the bernburg formation again a large fresh-water lake (or several large lakes) covered the central germanic basin, but periodically, the lake(s) dried out. the seis member was studied in detail for sait-content f1uctuations in the northern balaton highland (hungary), where deposi­ tion occurred in the marginal parts of the seis shallow­ water sea. the shallow-water deposits are in general normally marine, wi th a rich claraia fauna and con­ odonts. however, in some parts the fresh-water influx was so strong that on some bedding planes the marine fauna was replaced by a rich freshto brackish-water fauna with mass occurrences of in situ conchostracans (kozur, 1993; kozur & mock. 1993). in other beds hypersaline rocks with anhydrite nodules occur. thus, the combination of climatic changes (princi­ pally the short cooli ng in the low latitudes due to a vol­ canic winter) and lower to middle scythian superanoxia as the two main causes for the ptb biotic crisis were both caused by the unique large scale and violent explo­ sive volcanism in the uppermost permian and lower­ most triassic. 7. general extinction and recovery patterns connected to the ptb biotic crisis detailed knowledge of the exact extinction and re­ covery patterns in the upper permian and in the lower triassic (which can only be recognized by considera­ tion of the data and problems presented in sections 2-4) is most important for the reconstruction of a scenario of the ptb biotic crisis and the recognit ion of its causes. kozur (1998a) reported the following extinction and recovery patterns related to the ptb biotic crisis: the (siliceous) plankton (radiolarians). and the warm-water benthos (highly diverse upper permian warm-water benthos was restricted to the tethys), nektobenthos and nekton were the most strongly affected. the production of organic silica dropped so far that there is a lengthy, global radiolarite gap in oceans from a little below the ptb to the base of the upper olenekian. the cold-water faunas were either not, or slightly affected by the ptb biotic crisis. faunas of temperate zones with seasonal climate were slightly to moderately affected. there was a delayed ext inction event in cold-water adapted faunas that survived the ptb without ext inc­ tion, tlourished and diversified in the lowermost tri* assic after the extinction of the warm-water fauna in the tethyan realm. kozur: problems fo r evaluat ion of the scenario of the pennian-triass ic boundary ... the recovery time for the warm-water benthos and siliceous plankton was unusually delayed (about 5 ma) as this recovery occurred only in the upper olenekian to middle triassic interval. the recovery of the nekton and nektobenthos was mostly rapid, afte r one conodont zone (h. parvus zone that had a short duration <0.1 my). the productivity of the terrestrial plants dropped strongly and the recovery occurred mainly in the upper olenekian and in thc middle triassic. several extinction events occurred in the terrestrial faunas within the upper permian, considerably be­ low the marine ptb, and for different fo ss il groups at different stratigraphic levels. at the marine ptb, only a very slight extinction event can be observed in vertebrates, when "remnant" permian form s (dicyno­ don) disappeared. at, or close to, the often used con­ tinental ptb (fad of lystrosaurus) no extinction event of any terrestrial faunal element can be obser­ ved. such terrestrial faunal elements mainly survived the ptb biotic crisis, which were able to survive some months of extrem e climatic conditions , including severe drought, cold or even freezing conditions in low latitudes by hibernation-type live stages (verte­ brates) or by droughtand freeze-resistant eggs (con­ chostracans). good examples are the vertebrate lys­ trosaurus which is known both from low latitudes and from high southern latitude areas with polar night, the conchostracan fa/sisca which occurred both in low latitudes and in high northern latitudes within the permo-triassic polar circle, and the ostra­ cod darwinu/a which lived in tropical areas and high latitudcs. distinct terrestrial fl oral changes (that were not of local character) occurred during the upper dora­ sham ian , when in most parts of the world the trilete cavate spores of lycopodiales became dominant, whereas several species of gymnosperme pollen dis­ appeared. until the end of the permian a low diversi­ ty terrestrial flora was establi shed and the terrestrial plant production became low. during the lower and middle scythian the terrestrial plant production remained low (global coal gap). about 50 % of the genera that disappeared at the ptb re-appeared in the olenekian middle triassic interval (lazarus taxa). some of them had changed in generic level but had undoubtedly evolvcd from gen­ era that had disappeared at the ptb. in some groups the percentage of lazarus genera is 90-100 % (e.g. , holothurians, scolecodonts). only very few major fossil groups totally disap­ peared at the ptb (without lazarus taxa). most of these groups had a very low diversity and/or a regi­ onal restriction at the end of the permian to tethys or 153 even to eastern tethys (trilobites, rugose corals, fusu­ linids). the ptb is preceded by mass occurrences of marine (and continental?) fun gi and the fungal spike ended abruptly a little before the ptb, in eastern tethys at the base of the volcanic dust fall -out a littl e below the biochronologic ptb. the extinction was more severe in the northern than the southern hemisphere. 8. conclusion a possible scenario for the biotic crisis at the ptb this scenario for the ptb biotic crisis originated by consideration of the data and probl ems presented in sections 2-7 and from earlier works (kozur, 1997c, 1998a). it incorporates facts such as the severe dzhul­ fian dorashamian climate in many parts of the world caused by the continent-ocean configuration and by the siberian trap volcanism; the extinction event at the guadalupian -lopingian boundary that restricted most of the affected warm -water faunas to tethys; and the permian northward drift of pangaea leading to a middle and upper permian cooling of the boreal area which caused a successive middle permian extinction of warm-water benthos and an interruption of the ex­ change of warm-water benthos between the tethys and western north america during the guadalupian. the permian northward drift brought large parts of pangaea into the tropical -subtropical belt during the middle -late permian resulting in rather severe climatic conditions over large parts of pangaea during the upper permian, such as aridity and strong daily and seasonal temperature variations. part of the fauna adapted to sur­ vive several months of very severe climate (long drou­ ght, low winter temperatures below freezing point in areas with hot or warm summers). at the same time, northern pangaea reached the boreal realm and the middle-upper permian climate became colder and colder. thi s lead to extinction of major warm-water fo ssil groups in the arctic long before the ptb , as shown by the disappearance of the fusulinids at the base of the guadalupian. the faunal exchange of warm­ water benthos between tethys and the westem shelf of america was interrupted. therefore, a strong provin ­ cialism developed with different shallow, warm-water faunas on the western shelf of america and in tethys. a very rapid and extensive regression at the guadalupi­ an-lopingian boundary destroyed the habi tats of large shelf areas (e.g., the delaware basin of southwestern north america changed into a hypersaline bas in) , in other basins, like the phosphoria basin, the warm-water fauna was additionally harmed by wide-spread upwel­ ling of cold boltom water. connected regional extinc­ tions led to the disappearance of fusulinids on the west­ ern america warm -water she lf during the lowermost 154 loping ian. as benthi c warm-water faunas could no longer mi grate between tethys and western north america through the southern margin of the boreal sea, major groups such as the fu sulinids were restricted to the tethys in the upper dzhulfian and dorashamian. this is a lso the case for the warm-water clarkina sub­ carinala conodont lineage and for most groups of the reef communit ies. beginning in the middl e dzhulfian , the climate became periodically morc severe by the intluence of the ( in that time) largely explosive siberi an trap volcan ­ ism. the eruptions became stronger and stronger during the dorashamian. the reduecd strength of sunlight due to the presence of dust and sulphate aerosols favoured the development of marine (and continental?) fungi that became more and more common during the late dora­ shamian (tympanicys/a associat ion). acid rain hanned the gymnosperm forests and most other plants, but did not influence swamp fl oras with lycopodiales that were adapted to acid soi l. therefore in many parts of the world lycopod ialcs noras, as indicated by increasing amounts of trile te cavatc spores became common and in many places dominant , whereas the amount of gym­ nosperms decreased in the uppennost permian. repeti­ tive very short periods of cooling in low latitudes, coi1nected with dust and sulphate aerosols from the s iber­ ian trap vo lcanism, led to a drop in the diversity of ter­ restr ial vertebrates and fresh water faunas to the upper­ most permian. the larger te rres trial te trapods were affe c ted first whil e the conchostracans with drought ­ and freeze-res istant eggs were affected last. by these stepwise extinctions of different terres trial faunal gro­ ups, in the upper dorasham ian a low diversity terrestri ­ a l and fresh-water fauna was present, in which form s prevailed that could survive severe climat ic conditions, including short cooler periods in low latitude areas (lys trosaurus among the te rrestrial vertebrates, con­ chost racans, danvillula among the freshwater ostra­ cods) . forms adapted to a permanentl y warm climate become rarc (dicynodon). the cold climate in the bore­ al realm and a regress ion followed by a transgress ion lead to the es tablishment of a very low-diversity fauna during the upper dorashamian o/ocems collcavl/in and o. boreale zoncs (the uppermost part o[ thc latter zone s .1. be longs to the earlies t triass ic h. parvlls zone). highly diverse marine warm-water faunas were at that time res tri c ted to tethys, moderately diverse marine faunas occurred on the temperate perigondwana shelves. during the latest dorashamian and earliest triassic, around 252-250 ma ago, the effusion of the siberian trap basalis covered an area of at least 2.5 million km 2 , possi bly eve n 4~5 milli on km 2 • furthe rmore in the northern hemisphere a huge highly explosive fe lsic to intermediate volcan ism occurred at the no rtheastern tethys panthalassa margin. huge amounts of dust and sulphat e ae rosols were re leased into the atmosphere, and in the eastern tethys a fall -o llt of volcanic dust over an area of a t least 2 million km2 occ urred. dust geologia croalica 51/2 and sulphate aerosols lead to a drastic drop in tempera­ ture especially in low lat itudes (tethys!), which lasted about 3-6 months (volcanic winter w ith conditions s i­ milar to those calculated for a thermo-nuclear winter). drastically reduced sunlig ht at the earth 's surface and also a drop in water temperature on the tethyan shelves strongly affected the phytoplankton , the basic e lement of the marine food-chain. skeleton-bearing p lankton (radiolari a) that li ved in different watcr depths was additionally affected by the onset of the oceanic anoxia. the tethyan shelves, the rcfuge for most of the latest permian warm-water benthos were coo led below the temperatures critical fo r reef communiti es, and the entire warm -water benthos, but in many places al so most of the wam,-water nekton or nektobenthonic fau ­ nas (e.g. , wann-water conodonts) became extinct on the shelves. thi s climatic catastrophe was more severe in the northern hemisphere, where the two huge volcani c centres were situated , and especially severe in low northern latitudes, where the centre of the huge explo­ sive felsic-intermediate volcanism was located. the cold-water adapted fauna of the boreal realm was not affected by thi s cl imat ic catastrophe. the tem­ perate to coo l-water peri gondwana fauna was moder­ ately affected because there was no tropical warm ­ water benthos, and the climatic catastrophe was not as severe as in the northern hem isphere. a bipolar fauna was es tablished , as o/oceras from the boreal realm invaded thi s area close to the ptb , probably in connec­ tion with the volcanic wi nter. a global warming within the lower scythian (indi­ rectly re lated to the strong volcanism), which occurred a t the base of the gandarian (= dienerian), caused the extinction o f those co l d~water adapted taxa that were not affec ted by the vol cani c winter and flouri shed therefore during the uppermost dorashamian and low­ ermost tri ass ic in tethys, where they occupied all those biotopes, from which the te thyan warm-water fauna had disappeared. continuing acid rain in the gangeti an (in connec­ tion with the continuing s iberian trap volcanism) and the subsequent gandarian g lobal warming may be thc reasons fo r the delayed recovery o f the low latitude continental flora , especiall y in areas with a hot seasonal climate. the low diversity uppermost dorashamian terrestri ­ al and fresh water fauna , to a large extent a lready adapt­ ed to shorter periods of sevcre climate (freezing tem­ peratures or drought) surv ived to a large degree, afte r those faunal e lement s thai were adapt ed to a perma­ nent ly warm climate had died out earli e r during the dzhulfian and dorashamian. only rare las t representa~ tives of the latter fauna , like dicynodoll , became exti nct close to the ptb. the oppo rtunistic swamp dora was no t greatl y affected by a shortlasting temperature drop in low lati ­ tudes and acid rain, but many permian gymnosperm s di sappeared. in the eastern tethyan humid-tropical cathays ia province , rather distinct abrupt changes in kozur: problems for evaluation of the scenario of the pennian-triassic boundary ... the flora can be observed. the tropical filicales-pteri­ dospermophyta "rain forest" flora largely disappeared and the tropical highland nora with dominating gym­ nospenns survived. therefore, the cathaysia flora beca­ me rich in gymnosperms (sudden increase in bisaccate pollen) during the biotic crisis in connection with the volcanic dust fall-out, whereas in other floral realms the spores (especially of the lycopodiales swamp flora) became dominant against the bisaccate pollen . as a whole, both in the terrestrial plant diversity and terres­ trial plant bioproduction a minimum began with the volcan ic winter within the latest dorashamian (begin­ ning of the world-wide coal gap) and the terrestrial plant diversity /bioproduct ivity remained very low dur­ ing the lower and middle scythian (coal gap). only in the upper scythian (upper olenekian) the terrestrial land plant diversity recovered, but the first "post-crisis" coals are known only from middle triassic beds. the explosive eruptions at the northeastern tethyan volcanic centre were so strong that even the ozone layer was depleted. duc to the resulting strong uv radiation, the booming of marine (and continental?) fungi sudden­ ly ends at the base of the volcanic dust fall-out in eas t­ ern tethys and in contemporaneous levels in other parts of the world. the drop in waler temperature in the central tropical panthalassa was not severe enough to kill the warm­ wate r benthos on the narrow shelves of insular areas, where many warm-water taxa survived . however, these forms could not migrate to the faunistically depleted tethyan shelves because of the wide-spread oceanic anoxia that reached in an unusually shallow level above the storm-wave base. therefore, the recovery of the warm-water benthos on the tethyan shelves was dela­ yed [or about 5 my until the end of the superanoxi a in thc upper olenekian and middle triassic. as the sha[· low-water shelves around oceanic islands are unstable biotopes, many relic biotopes were destroyed during this period. thus, finally, the strongly dclayed recovcry led to a delayed extinction, but many taxa survived this lengthy interval of relative isolation. after the end of the oceanic anoxia about 50 % of the genera that disap­ peared at the ptb re-appeared unchanged or slightly changed during the upper olcnekian and middle trias­ sic. this reappearance of lazarus taxa is followed by a radiation of the warm-water benthos during the middle and upper triassic. this sccnario exp lain s nearly all the details of the cxtinction patterns in continental and marine biotopes as well as the delayed recovery and the high percentage or lazarus taxa that re-appeared during the upper ole­ nekian and middle triassic. only two facts arc difficult to explain. one is the strongly delayed recovery of the siliceolls plankton (radiolarians) that began only in the uppcr olenekian. this delayed recovery can partly be explained by the oceanic superanoxia because not all palaeozoic-mesozoic radiolarians lived in the upper­ most, anoxia-free water column. however, those radio­ larians that lived near the surface of the oceans should 155 have recovered very quickly as an anoxic ocean is espe­ cially nu trient-r ich (hallam & wignall, 1997). however, these radiolarians, to which the oertlispongi­ dae and a part of the entactinaria belong, did also not recover before the late olenekian or the middle trias­ sic. a possible explanation for this is that nearly all skeleton-bearing radiolaria became ext inct ncar the ptb, and the triassic radiolarian fauna developed anew from skeleton-less or spicular radiolarians (kozur et ai., [996a). superanoxia cannot explain the delayed recovery of the high productivity of terrestrial plants that also occurred in the upper olenekian. in low latitudes with a hot seasonal climate this may be explained by a strong warming within the gandarian (= dienerian). however, such a global climate would favour the terrcstrial pl ant productivity at high latitudes, but there the productivity also remained low. thus, the high latitude gondwana areas with permian coals have no lower triassic coals, which do not exist anywhere else either. in the gange­ tian, the terrestrial plant community may have been harmed by acid rain triggered by the conti nuing siber­ ian trap volcanism, but in the gandarian and lower olenekian this volcanism was finished, and no distinct recovery of the terrestrial plant productivity can be observed in that time. a possible explan ation for the delayed recovery of the terrestrial plants is the strong ext inction event of the fungi in the uppermost permian, most probably caused by strong uv radiat ion due to destruction of the ozone layer. for dense vegetation comparable with tropical rain forest, the activity of microscopic fung i is decisive important. without or with strongly reduced activities of these fungi such dense vegetation cou ld not sufvivc for longer time because the recycling of the organic matter would be very much disturbed, and the soil would become too poof for a dense vegetation. as the recovery of the terrestrial plants, the plank­ tonic radiolaria ns and of the warm-water benthos occurred contempo raneously in the upper olenekian and middle triassic, there may sti ll be some unknown factors that prevented the lower and middle scythian recovery of the biota additional to the marine anoxia. some of the factors that lead to the ptb biotic crisis are today caused by man-made destructions of the envi­ ronment, such as increase of atmospheric co2, air pol­ lution, begi nning destruction of the ozone layer, pollu­ tion of the sea, and destruction of the tropical rain forests. as the study of the phanerozoic biodiversity has shown, the biosphere recovers vcry fast, if the harmful factors disappeared. this, however, is possible only until a certain level of environmental and bios­ phere destruction. beyond this level, self-strengthen ing effects of the environmcntal and biosphere destruction come into existence that can lead to an environmental catastroph and biotic crisis (mass extinction etc.). the recent extinction rate, which is caused mainly by envi­ ronmental and biotic destruction by negative effects of human activities, is very high. the estimations are 156 between a daily extinction rate of74 species (sepkos­ ki , 1997) and 150 species (ehrlich & wilson, 199 1). according to briggs (1994) the extinction rate is today highest in the phanerozoic. even at the lower est im ation , the present extinction rate is close to the ex tinc tion rate around the ptb. deci sive important parts of the biosphere, such as marine plankton as the prim ary source of the food chain, are not yet affected in a g lo bal scale. however, this may happen in nea r future, if the destruction of environment and biosphere co ntinue in the present level or even grow. then the leve l wi ll be reached, at wh ich the self-strengthening and back feeding processes of a biotic crisis will domi­ nate . thus, protection o f the environment and of the biosphere diversity may become soon a question of sur­ vival for the mankind. acknowledgements prof. dr. i-lei fried mostler, innsbruck and pro f. dr. lasenka srem ac, zagreb, improved this paper by very care ful reviewing . i am also very gratefu l to dr. julie robson, southminster, for her language ed iting and very usefu l comments. 9. references adamczak, f. (1969): on the question of whether the palaeocope ostracods werc filter-feeders .in: nea le, l.w. (cd. ): the taxonomy, morphology and ecology of recent ostracoda. oliver & boyd, 93-98, edinbu rgh. alberti, von, f. ( 1834): bei trag zu einer mono­ graphc dcs bunt en sandste ins, musche lkalks und keupers und die verbindung dieser gebilde zu ein­ er formation.verlag der j.g. cotta 'schen buch­ handlung, stuttgart and tubingen, 366 p. balme, b.e. ( 1979): palynology of permian-triass ic boundary beds at kap stosch, east greenland. ­ medd. gr0n l. , 200/6, 1-37. baud, a., atudorei, v. & sharp, z. (1996): late permian and early triassic evo lution of the north­ ern indi an margin: carbon isotope and seq uence stratigraphy.geodinamiea acta, 9/2, 57-77. boomer, l. & whatley, r. (1992): ostracoda and dysacrobia in the lower jurass ic of wales : the reconstruct ion of past oxygen levels.palaeogeogr. , palaeoelimatol. , palaeoecol. , 99, 373-379. briggs , j.c. (1994): mass extinctions: faelor falla­ ey?in: glen, w. (ed.): the mass exti nction deba­ tes: how science works in a crisis. stanford univer­ sity press, 230-236, stanford. cheng , z., han , y. , hou , j., li, j. , lt, p. , lt, y. , ltu, s., liu, y. , qu, l., shen, b., sun, s., wu , geologia croatica 5 1/2 s. , xiao, s., yang, j. & zhang, z. (1989): research on the boundary between permian and triassic strata in tianshan mountain of china.chi­ na ocean press, beijing, 176 p. dagys, a. (1994): correlation of the lowermost tri­ assie.albertiana, 14,38-44. dagys, a. & ermakov, s. ( 1996): induan (trias­ sic) ammonoids from north -eastern as ia.rev. paleobiol., 15/2,401-447. detre, cs., toth, i., don, gy. , solt, p., guc­ sik, a. , kiss, a.z., uzonyi , i. & berczi, sz. (1998): a nearby supernova explosion at the permo­ triass ic boundary.23rd symposium on antarctic meteorites, juni 10-1 2, 1998, nationa l institute polar research, 23-24, tokyo. diener, c. (19 12): the triass ic of the himal ayas.­ mem. geol. surv. india, 36/3, 176 p. ding, m., zhang, k. & lai , x. ( 1995): discussion on lsarcicella parva of the early triassic.palae­ oworld , 6, 56-63. dobruskina, la. & mogutcheva n.k. (1987): about the age of the tungusska basin volcanics. ­ geol. geophys., 1987/1 ,29-36 (in russian). ehrlich, p.r. & wilson, e.o. (1991): biodiversity studies: science and poliey.science, 253, 58-62. erwin, d.h. (1993): the great palaeozoic crisis. life and death in the permian.columbia univers ity press, new york, 327 p. foster, e.b. (1997): the permian-triassic boundary in aus tralia: where is it and how is it exprcssed?­ in: shi, g.r. (cd. ): the pemlian of eastern tethys: biostratigraphy, palaeogeog raphy and resources. abstracts, deakin university, technica l paper, 3, 51-52, melbourne. gr iesbach, e.l. (1880): pal eontological notes on the lower trias on the himalayas.rec. geol. surv. india, 13/2, 94-113. hallam, a. (1994): the earliest triass ic as an anox­ ic event , and its relationship to the e nd-palaeozoic mass extinction.canadian soc. petrol. geo !. , mem. , 17, 797-804. hallam, a. & wignall, p.b. ( 1997): mass exti­ nctions and their aftermath.oxford univers ity press, oxford-new york-tokyo, 320 p. hao, w.e. ( 1992): early triass ic marine ostracods from guizhou.acta mieropaleon!. siniea, 9/1 , 3744. henderson, e.m. (1993): arc permian-tri assic boundary events diachronous? ev idence from the canad ian arctic.carboniferous to jurass ic pangea, program and abstracts, 136, calgary. henderson, e.m. & baud, a. (1996): correlation of the pennian-triassic boundary in arctic canada kozur: problems for evaluation of the scenario of the pemlian-triassic boundary ... on the basis of molluscan and conodont distribu­ tion.30th international geological congress, abs­ tracts, 2, 63, beijing. hoffmann, a., gruszczynski, m., malko­ wski, k. & szaniawski, h: (1998): should the permianftriassic boundary be defined by the carbon isotope shift?acta geol. polonica, 48/2,141-148. holser, w.t., schonlaub, h.p., boeckel­ mann, k., margaritz, m. & orth, c.l (1991): the permian-triassic of the gartnerkogel-l core (carnic alps, austria): synthesis and conclu­ sions.abh. geol. b.-a., 45, 213-232. igo, h. (1996): silurian to triassic conodont biostra­ tigraphy in japan.in: first asian conodont sym­ posium. acta micropaleont. sinica, 13/2, 143160. isozaki, y. (1994): superanoxia across the permo­ triassic boundary: record in accreted deep-sea pelagic chert in japan.canadian soc. petrol. geol., mem. 17,805-812. isozaki, y. (1997): permo-triassic boundary supera­ noxia and stratified superocean: records from lost deep-sea.science, 276, 235-238. jin, y., shen, s., zhu, z., mel, s. & wang, w. (1996): the selong section, candidate of the global stratotype section and point of the permian-triassic boundary.in yin, h. (ed.): the palaeozoic-meso­ zoic boundary. candidates of global stratotype sec­ lion and point of the permian-triassic boundary. china un ivers ity of geosciences press, 127-137, wuhan. koike, t. (1996): the first occurrence of griesbachi­ an conodonts in japan.trans. proc. palaeont. soc. japan, n.s. 181,337-346. kotly ar, g.v., kozur, h. & zakharov, yu.d. (1993): the transcaucasian sections dorasham 2 (azerbaidzhan) and sovetashen (armenia), two ca­ nd idates for prr boundary reference seclions.afbe­ rtiana, 12,36-38. kozur, h. (1973): die bedeutung der triassischen scolecodonten insbesondere fiir die taxonomic und phylogenie del' fossilen eunicida. hat sich die syn­ these von "ort hotaxonomischen" und "parataxono­ mischen" system in del' praxis bewahrt?mitt. ges. geol. bergbaustud., 21, 745-776. kozur, i-i. (1985): biostratigraphic evaluation of the upper palaeozoic conodonts, ostracods, and holo­ thurian sclerites of the bukk mrs., part ii: upper palaeozoic ostraeods.aeta geo!. hungar., 28/3-4, 225-256. kozur, h. (1989): thc pcrmian-triass ic boundary in marine and continental sediments.zentralblatt fijr geologie und palaontologie, 1988/11-12, 12451277. 157 kozur, h. (1991): permian deep-water ostracods from sicily (italy). part 2: biofacial evaluation and remarks to the silurian to triassic paleopsychros­ pheric ostracods.geol. palaont. mitt. innsbruck, sonderbd., 3, 25-38. kozur, h. (1993): range charts of conchostracans in the germanic buntsandstein.in: lucas, s.g. & morales, m. (eds .): the nonmarine triassic. new mexico mus. nat. hist. & sci., bull., 3, 249253. kozur, h. (1994a): the permianftriassic boundary and possible causes of the faunal change ncar the pft boundary.permophiles, 24, 51-54. kozur, h. (1994b): the correlati on of the zechstein with the marine standard.jb. geol. b.-a., 137, 85103. kozur, h. (1995a): permian conodont zonation and its importance for the permian stratigraphic standard scale.geol. palaont. mitt. innsbruck, 20, festsch­ rift zum 60. geburtstag von helfried mostler, 165-205. kozur, h. (1995b): some remarks to the conodonts hindeodus and isarcicella in the latest permian and earliest triassic. palaeoworld, 6, 64-77. kozur, h. (1996a): some remarks to the permian standard scale.guadalupian ii, alpine, texas, april 10-13 , 1996, abstracts, 7-11, 13, 14, wash­ ington. kozur, h. (1996b): the conodonts hindeodus, isar­ cieella and sweetohindeodus in the uppermost per­ mian and lowermost triassic. geol. croatica, 49/1, 53-96. kozur, h. (1996c): the permian-triassic boundary (ptb) in marine and continental beds possible ca­ uses for the ptb biotic crisis.30th igc, abstracts, 2,55, beijing. kozur, h. (1996d) : changes in marine ostracod fau ­ nas at the permian-triassic boundary.3eme con­ gres europeen des ostracodologislcs paris bier­ ville, 8-12 july 1996,40, paris. kozur, h. (1997a): pelagic permian and triassic of the western tethys and its paleogeographic and stratigraphic sign ificance.48. bergund hiitlcn­ mannischer tag, abstract, 21-25, freiberg. kozur, i-i. (1997b): the effects of the permo-triassic boundary biotic crisis on different faunal groups and its possi ble causes.13th international symposium on ostracoda is097 , abstract vol., 31, london. kozur, h. (1997c): possible scenario for the biotic crisis of the pennianffriassic boundary.unesco­ iocp proj ect #335 "biotic recoveries from mass extinctions", final conference "recoveries '97", 1822, praha. 158 kozur , h. (1997d): the permian conodont biochro­ noloy: progress and problems.in: s hi , g.r. (cd.): the permi an of eastern tethys: bios tratigraphy, palaeogeography and resources. abstracts, deakin univ., technical paper, 3, 79-82, melboumc. kozur, 1-i.w. (l998a): some aspects of the pcrm ian­ triassic boundary (ptb) and of the possible causes for the biot ic cri sis around this boundary. palaeo­ geogr. , palacocl imatol. , palaeoeeol. , 143 , 227-272. kozur ( 1998b): upper triassic punciacca , the con­ necting link between the palaeozo ic to lower trias­ sic kirkbyacea and the cretaceous to cenozoic pun­ ciacca.bu ll. cent re rech. , elf explor. prod. mem., 20,257-269. kozur, h.w., kaya , o. & mostler, h. (1996a): firs t ev idencc of lower to middle scythi an (die­ nc ri an lower olenekian) radi o larians from the karakaya zone of north western turkey.geo!. palliont. mit t. innsbruck, sonderbd ., 4, 271-285. kozur , h. & mock, r. (1974): holothurien-sklerite aus de f trias def siowakei und ihre stratigraphische bedeutu ng. geol. zborn. , geol. carpathica, 25/1, 11 5145. kozur , h. & mock, r. (1993): thc importance of conchostracans for the correlation of continental and marinc bcds.in : lucas , s.g. & morales , m. (cds.) : the nonmarine triass ic . new mexico mus. nat. i-list. & sci., bull. , 3, 261 -266. kozu r, 1-1., ramoys , a. , wang, c.y. & zakha­ roy , y. (1996b): the im portance of hindeodus parvu s (conodonta) fo r the de fini tio n o f the permian triassic boundary and evaluation o f the proposed sections for a g lobal stratotype section and poin t (gssp) for the base of thc tri assic_geolo­ gija, 37/38, 173-213, ljubljana. kozu r, j-1 . & seidel, g. (1983) : die biostrati gra­ phie des unteren und mittleren buntsandsteins unter besonderer berlicks ichtigung der conchostracen. ­ z. gcol. wiss., 11 /4, 429-464. krystyn , l. & orchard, m.j. (1996): lower­ most triass ic ammonoid and conodont biostratigra­ phy of spit i, india.albertiana, 17, 10-21. lai, x. , ding, m. & zhang, k. (l 996a): the signif­ icance of the discovery of isarcicella isw·cica at the meishan pe rm ian-triassic boundary stratotype sec­ tion in changx ing, zhejiang provincc.exploration of geoscicnces, 11 ,711. lai, x. , yang , f. , hallam, a. & wignall, p.b. (1996b): the shangsi section, candidate of the glo­ bal stratotype section and point of permian-triass ic boundary.in : yin, h. (ed.): the palacozoic-meso­ zoic boundary. candidates of global stratotype sec­ ti on and point of the permian-triass ic bound ary . china un iversit y of geosc iencs press, 11 3-124 , wuhan. geologia croatica5 1/2 let hi ers, f. & whatley, r. ( 1994): the use of ostracoda to reconstruct the oxygcn icvcls of late palaeozoic oceans.marine m icropa leont. , 24, 5769. lethiers, f. & whatley, r. (1995): oxygenat ion des caux et ostracodes filt reurs : appl icati on au devonien-dinantien.geobios, 28/2, 199-207. lozoysky, y.r. (1993): the most comp lcte and fos­ sili fe rous lower triass ic sec ti on of the moscow syneclise: the best candidate fo r a nonmarine g lob­ al timc seale.in: lucas, s.g. & morales , m. (cds.) : the nonmarine tri ass ic . ncw mex ico mus. nat. hist. & sci., bull. , 3, 293-295. lucas, s.g. (1 993): vertebrate biochronology of the triassic of china.in : lucas, s.g. & morales , m. (cds.): the non marinc triass ic. new mex ico mus. nat. hist. & sci., bull. , 3, 30 1-306. matsuda, t. (1 98 1): early triassic conodonts from kashmir, india. part i: hindeodus and isarcicella.­ l ournal o f geosciences, osaka c it y university, 24/3,75 -108. mel, s. (1996): restudy of conodonts from the penni­ an-triass ic boundary beds at se long and meishan and the natural permian-tri ass ic bo undary .in: wang, h. & wang , x. (eds.): centennial memo­ ri al yolume of pro f. sun yunshu: palaeontology and stratigraphy . china uni versity of geosc iences press, 14 1-148, beijing. mostler, h. (1969): entwicklungsreihen triass ischer holothurien-sklerite.alpenkundl ichc stud ien, 7, 53 p. mostler, h. (1973): holothuriensklerite der alpinen trias und ihrc strati graphische bedeutung. mitt. ges. geol. begbaustud ., 2 1,729-743. most ler, h. & rahimi-y azd, a. ( 1976): ncue holothuricnskleritc aus dem oberpcrm von julfa in nordiran.geol. pajaont. mitt. innsbruck, 5/7, 1-35. newell, n. d. (1994): is therc a prccisc permian-tri­ assic boundary?pennophi les, 24, 46-48. paull, r.k. & paull, r.a. (1 994): h indeodlls par­ vus proposed index foss il for the permian-triassic boundary.lethaia, 27,27 1-272. perch-nielsen, k., birkenmajer, k., birke­ lund, t. & aellen, m. (1974): revision of tri­ assic stratigraphy of the scoresby land and jamc­ son land region, east grcenl and. gr0nlands geo!. unders., bull. , 109, i -51. posenato, r. (1 991 ): endcmic to cosmopoli tan bra­ chiopods across the p(fr boundary in the southern alps (it aly).in : proeeedings of shall ow tethys, saito ho-on kai special publi cati on, 3, 125 -1 39, sendai. renn e, p.r. , zhan, z., richards, m. a., bla­ ck, m.t. & bas u, a.r. (1995) : synchrony and kozur: problems for evaluation of the scenario oflhe pennian-tri,lssic boundary ... causal relations 'between permian-triassic boundary crises and s iberian flood volcanism.science, 269, 14131415. rigby, j.k. & gosney, t.c. (1983): first reported triassic lyssakid sponges from north america.j. paleonl. , 57/4, 787-796. sadovnikov g.n. (1997): taimyrian stage of the terminal non-marine permian. in: podemski, m.; dybova-jachowicz, s., jaworowski, k. , jureczka, k. & wagner, r. (cds.): proceed­ ings of the xiii internat ional congress on the car­ boniferous and permian. prace panstw. inst. geol. , 157,133136. sadovnikov, g.n. & or lova, e.f. (1993): the lower boundary and biostratigraphy o f the nonma­ rine triassic in siberia.in: lucas, s.g. & mor­ ales, m. (eds.): the nonmarine triassie. new me­ xico mus. nal. hisl. & sci., bull. , 3, 421-422. sadovnikov, g.n. & orlova, e.f. ( 1994): tai­ myrian stage the terminal stage of the continental permian.dok!. an russia, 338/5, 658-661 (in russian). sepkoski, j.j . (1997): biodiversity: past, present, and future.j. paleonl. , 71/4, 533-539. so hn , i.g. (1970) : early triassic marine ostracodes from the salt range and surghar range, west pak­ istan.in : kummel, b. & teichert, c. (eds.): stratigraphic boundary problems: permian and tri­ assic of western pak istan. uni vers ity press, 193206, kansas. sweet, w.c. (1976) : conodonts from the permian­ tri assic boundary beds at kap stosch, east green­ land.medd. gr~n land, 197/5,51-54. teichert, c. & kummel, b. (1976): permian-tri­ assic boundary in the kap stosch area, east green­ land.medd. gr~nland, 197/5,3-49. tozer, e.t. ( 1967): a standard for triass ic time.­ bull. geol. surv. canada, 156, 1-103. tozer, e.t. ( 1988): defi nition of the permian-trias­ sic (p-t) boundary : the ques tion of the age of the oloceras beds.mem. soc. geol. it., 34, 291-301. tuzhikova, v.1. (1985): miospory i strat igra fij a opornych razrezov triasa urala. nizhnij trias, pogra­ nichnaja verchnaja perm.akademia nauk sssr, uralskij nauchnij centr, sverdlovsk, 23 1 p. vissher, h. ( 1971): the permian and triassic of the kingscourt outli er, ireland. geo !. surv. ire land , spec. paper, i , 114 p. wang, c.y. ( 1994): a conodont-based hi gh-resolu­ tion eventostratigraphy and biostratigraphy for the permian-triassic boundaries in south china.palac­ oworld, 4, 234-248. 159 wang, c.y. (1995a): conodonts from the permian­ triass ic boundary beds and biostratigraphic bound­ ary in the zhongxin dad ui section at meishan, changx ing county, zejiang province, china.albe­ rtiana., 15, 13-19. wang , c.y. (1995b): conodonts of the permian-tri ­ assic boundary beds and biostrat igraphic boundary. ­ acta palaeontologica sinica, 34/2, 130-151. wang, c.y. (1995c): upper permian conodont stan ­ dard zonation.permophiles, 26, 20-23. wang , c.y. (1996): conodont evolutionary lineage and zonation for the latest pcnn ian and earliest tri­ assic.permophiles, 29, 30-37. wang, c.y., kozur , h. , ishiga, h., kotlyar , g.v., ramovs, a., wang z.h. & zakharov, y. (1996): permian-triassic boundary at meishan of changx ing county, zhcj iang province, china a proposal on the global stratotype section and poin t (gss p) for the base of the triassic.in: first asian conodont symposium. acta micropaleonl. s inica, 13/2, 109-124. wang, c.y. & wang, s.q. (1997): conodonts from permian-triassic boundary beds and evolutionary lineage of hindeodus isarcicella .acta palaeon to­ logica sinica., 36/2, 15 1-169. wang, k., geldsetzer, h.h.j. & krouse, h.r. (1994): permian-triassic ex tinction : organic 813c evidence from british columbia, canada.geology, 22, 580-584. wang, y., chen, c., rui, l., wang, z., l1ao, z. & he, j. (1989): a potential global stratot ype of permian-triassic boundary.development in geo­ science, contribution to 28th international geologi­ cal congress, 1989, washington d.c. usa, science press, 22 1-229, beijing. whatley, r. (1 995): ostracoda and oceanic palaeo­ oxygen leve ls.mitl. hamb. zool. mus. insl. , 92 (ergbd.),337-353. wignall, p.b. & hallam, a. (1992): anoxia as a cause of the pennianrrriassic mass extinction: faci ­ es ev idence from northern it aly and the western united states.palaeogeogr. , palaeoclimal. , palaeo­ ecol. , 93, 2 1-46. wignall, p.b. & hallam, a. (1993): griesbachi­ an (earliest triassic) palaeoenvironmental changes in the salt range, pakistan and southeast china and the ir bearing on the permo-triassic mass extinc­ ti on.palaeogeogr. , palaeoclimato!., palaeoeco l. , 102,215-237. wignall, p.b. & hallam, a. (1996): facies cha­ nge and the end-permi an mass ex tinct ion in s.e. sichuan, china. palaios, 11 , 587-596. wignall, p.b., hallam, a., lai, x. & yang, f. (1995): palaeoenvironmental changes across the 160 geolog ia croatica 5 [/2 plate i hilldeodus lalidenloills praeparvlis kozur, x275, sample 68 kc 33, east greenland, lac. 2.1 after teichert & kummel (1976), corresponds about beds 8 and 9 in river 1 section after teichert & kummel (1976). this level is situated in the river 1 section 1-15 m above the last occurrence of oloeeras, and claraia occurs in the upper part of this level. probably t. pascoei zone. lower part of h. parvus zone. 2 hindeodus lafidenfafus praeparvus kozur with very large, but broad cusp, but denticulation similar to h. iypicalis (sweet), x92, sample 68 kc 33 (see fig. i). 3 very primitive hilldeodus parvus (kozur & pjatakova), cusp still very broad as in h. latidentatlls praeparvus, but this is seemingly partly caused by fusion with the following denticle in the lower half of the cusp, transitional form to h. latidelltows praeparvlis kozur, x92, sample 68 kc 33 (see fig. i). 4 primitive hindeodlls pm'vlls (kozur & pjatakova), x92, sample 68 kc 33 (see fig. 1). 5 hilldeodus latidelltatlls praeparvlis kozur, x92, sample 68 kb 8 b, river i section after teichert & kummel (1976), 1-7 m above the last otoceras, somewhat below the first occurrence of claraia. probably t. pascoei zone. basal part of h. parvus zone. 6 transitional form between hilldeodus parvlis (kozur & pjatakova) and h. latidelltaills praepa,-vus kozur, x92, sample 68 kb 8 b (see fig. 5). 7 very primitive hilldeodlls parvlis (kozur & pjatakova), x92, sample 68 kb 16 b, river i section after teichert & kummel (1976), beds with claraia, >30 m above the last otoceras. probably ophieeras commune zone. h. parvlls zone. 8 hilldeodlls par viis anterodelltallls (dai & zhang), x 128, sample 68 kc 42 a, east greenland, lac. 2.1 after teichert & kummel (1976), 54 m above sample kc 33. isareicella isarcica zone. 9 hindeodlls lalidelllallls praeparvlis kozur, x92, sample 63 ta122 (for sample position see sweet, 1970), pakistan, chhidru west a, basal kathwai member, upper dorashamian (uppermost permian). 10 hilldeodlls lalidelllallls (kozur, mostler & rahimi-y azd), x92, sample 63 ta-122 (see fig. 9). 11 hilldcadus latidentatus praeparvus kozur, x92, sample 63 ta122 (sec fig. 9), 12 hilldeodlls parvlis (kozur& pjatakova), x64, sample 63 k 3-5 (for sample position see sweet, 1970), pakistan, chhidru west a, lower kathwai member, clay bed ca. 1.3 m above sample 63 ta-122. h. parvlts zone of lowermost triassic. kozur plate! 161 162 permian(triassic boundary at shangsi (n. sichuan, china).hi storical biology, 10, 175 -1 89. wignall, p. b., kozur , h. & hallam, a. (1996) : on the tim ing of palaeoenvironmental changes at the permo-triassic (prrr) bo undary using conodonl biostratigraphy.historical biology, 12,39-62. wignall, p.b., morante, r. & newton, r. ( j 998) : the permo-triassic trans ition in spitsber­ gen: 813corg chemostrat igraphy, fe and s geochem­ istry, facies, fau na and trace foss ils.geo!. mag., 135/1,47-62. xia, f. & zhang , b. ( 1992): age of the sc10ng g ro­ up, selong of xizang (tibet) and the permian-trias­ sic boundary.joum. strat., 16/4,256-263. yin, h. (1985): on the transitional beds and the pcrmi ­ an-triassic boundary in south china.news!. stral, 15/1, 13-27. yin, h. (j 993) : a proposal for the g lobal stra lotype section and point (gss p) of the permian -tri assic boundary.albertiana, 11,4-30. yin, h., sweet, w.e., glenister, b.f., kotl­ y ar, g., kozur, r. , newell, n.d., sheng, j. , yang, z. & za kharov, y.d. (i 996a): reco­ mmendation or the meishan section as glob,\j stra­ totype section and point for basal boundary of tri­ assic system.news!. stratigr., 34/2, 8 1-1 08. yin, h. , zhang , k. , wu , s. & peng, y. (l996b): global correlation and definition of the permian­ triassic boundary.in: yin, i-i. (ed .): the palaeo­ zoicmesozoic boundary. candidates of global stra­ totype section and point of the permian -triassic boundary. china univers ity of geosc iences press, 3-28, wuhan. yin , 1-1. & z hang, k. (1996): eventostratigraphy of the permian-triassic boundary at mei shan section, geologia croat ica 51/2 south chi na. in : yin, h. (ed. ): the palaeozoic­ mesozoic boundary. cand idates of global stratotype section and point of the permian-triassic boundary. china univers ity of geoseienes press, 84-96, wu ­ han. zakharoy, yu.d., kotlyar , g.v. & olen 1koy, a.v. (1995): late dorashamian (late chang­ x ing ian) invertebrates of the far east and permi an to triassic volcanism in the western circumpacific.­ geo!. pac. ocean, 12,47-60. za widzka, k. (1971 ): a polychae te jaw appara tus and some seoleeodonts from the pol ish middle tri­ ass ie.actageo!. polonica, 2 1/3, 36 1-377. z hang, k. , ding , m. , la i, x. & ll u, 1. ( 1996): conodont sequences of the permian-triassic bound­ ary strata at mei shan sectio n, south chi na. in: yin, i-i. (ed.): the palaeozo ic-mesozoic boundary. candidates of global stratotype section and point of the permian-triassic boundary. china university of geosciencs press, 57-64, wuhan. z hang, k., lai, x., ding , m. & llu, j. (1995 ): conodont sequence and it s g lobal correlati on of permian-tri assic boundary in meishan sect ion , changx ing, zhejiang provin ce.earth science, journal of ch ina university of geosc iences, 20/6, 669-676. z hu, x. & lin, l. (1997): typical hindeodus parvus and it s s ig nificance and discussion on p{f bound­ ary.joum. jiangxi normal univ., 21/1 , 88-95. zhu, x.s., wang, c.y., lu, 1-1. , mu, x.n. , zhang, l.x. , qin, z.s., luo, i-i. , yang , w.r. & deng , z.q. ( 1994): permian-tri ass ic boundaries in jiang­ x i, china.acta micropa laeonl. sinica, 11 /4,439453. manuscript received june 25 , 1998. rev ised manuscript accepted november 23, l998. schlagintweit.indd 1. introduction microproblematica are microfossils whose suprageneric taxonomic status is unknown. many microproblematica display an encrusting way of life and can therefore be included in the group of “micro-encrusters” that during the upper jurassic were conspicuous components of microbial carbonate crusts (e.g. leinfelder et al., 1993; schmid, 1996; dupraz & strasser, 1999, 2002). these forms are widespread in shallow water platform carbonates where they show more or less pronounced facies sensitivity: that is they can be used in the characterization of certain carbonate palaeoenvironments. however, in contrast, they are only rarely useful for biostratigraphic purposes. in a recent iberopora bodeuri granier & berthou 2002 (incertae sedis) from the plassen formation (kimmeridgian–berriasian) of the tethyan realm felix schlagintweit contribution, the new microproblematicum iberopora n. gen. with the type-species iberopora bodeuri n.sp. was reported from the berriasian of portugal by granier & berthou (2002). an adequate description (without generic, species diagnosis) was presented, but little information was provided concerning other occurrences, or facies, and stratigraphic data. as only one reference (the type region) was cited in the synonymy, almost nothing is known about its palaeogeographic distribution. in this discussion regarding upper jurassic to lower cretaceous material from the northern calcareous alps of austria and already published in part (schlagintweit & ebli, 1999) the species was refered to as “krustenproblematikum” schmid, 1996). here we summarize the available data to provide more complete information concerning this so far poorly known taxon. 2. geological setting of the alpine occurrences after the drowning of the upper triassic shallow water carbonate platform of the austroalpine shelf (e.g. tollmann, 1985), several lithologies representing deeper water sediments prevailed during the lower and middle jurassic as, for example, condensed sequences of red and grey limestones and radiolarites (e.g. böhm, 1992; gawlick, 2000). the reinstallation of a shallow water facies known as the plassen formation began in the kimmeridgian and persisted only into the lower cretaceous (berriasian) in accordance with a proposed model of a compressional regime related to the late kimmerian or eohellenic orogeny (gawlick et al., 1999). for a long time it was generally accepted that these shallow water carbonates were deposited on uplifted slide-masses of hallstatt limestones with transgressive conglomerates at the base (e.g. tollmann, 1987; steiger & wurm, 1980; mandl, 2000). new investigations have shown that this model cannot be applied to the typelocality mount plassen in the austrian salzkammergut or to the krahstein in the styrian salzkammergut (schlagintweit et al., 2003b). the deposition of shallow water carbonates in the central nca began on rising thrusts (e.g. trattberg rise) caused by the closure of the tethyan ocean and by late jurassic nappe geologia croatica 57/1 1–13 2 figs. 2 pls. zagreb 2004 key words: incertae sedis, upper jurassic, lower cretaceous, plassen formation, northern calcareous alps, austria. lerchenauerstrasse 167, d-80935 munich, germany; e-mail: ef.schlagintweit@t-online.de abstract iberopora bodeuri granier & berthou 2002, formerly known as “crust problematicum” (schmid, 1996) is described from the plassen formation (kimmeridgian–berriasian) of the northern calcareous alps (nca). here, it occurs either as an incrustation on corals/stromatoporoids or it forms nodular masses (“solenoporoid morphotype”). it is typically found in the fore-reef facies of the platform margin, and (upper) slope deposits where autochthonous dasycladales are absent. water turbulence appears to control the morphological development of iberopora. thus, flat crusts appear in less agitated settings. the crusts are almost always accompanied by calcareous sponges/sclerosponges and abundant micro-encrusters, mostly koskinobullina socialis cherchi & schroeder and “tubiphytes” morronensis crescenti. the stratigraphic range of iberopora known to date is oxfordian–berriasian. in addition to the northern calcareous alps, it has been reported from the epicontinental area of nw-germany, the northern margin of the penninic and tethyan ocean (slovakia, switzerland, spain, poland, portugal) and the southern tethyan domain (greece, romania, yugoslavia). until other morphological elements (e.g. reproductive organs or protoconch) are found, its systematic position remains uncertain. currently, it is considered questionably to be an ancestral rhodophyceae or acervulinid-like foraminifera. 2 geologia croatica 57/1 3schlagintweit: iberopora bodeuri granier & berthou 2002 (incertae sedis)... thrusting (frisch & gawlick, 2003, and references therein). at mount plassen, the plassen formation evolved by shallowing upward without interruption from cherty basin deposits (oxfordian/kimmeridgian boundary – wegerer et al., 2003) into slope, platform margin (e.g. labyrinthina grainstones) and back-reef deposits followed by sea-level controlled transgressive–regressive cycles of open lagoonal and tidal flat facies (schlagintweit et al., 2003a). the upper tithonian of the type-locality is represented by muddy lagoonal limestones (wackestones, mudstones, floatstones) with gastropod lumachelles, stromatoporoid carpets, dasycladales and benthic foraminifera. without a real transition zone (“facies telescoping”), bioclastic packstones with corals appear, followed by slope deposits reflecting the final drowning of the plassen sedimentary megacycle. thus platform margin and slope facies occur twice, in the initial shallowing upwards-phase (kimmeridgian) and the final drowning succession (?uppermost tithonian, berriasian). in these deposits, the incertae sedis microfossil iberopora bodeuri granier & berthou has been detected at the plassen, krahstein and trisselwand localities. it is noteworthy that, according to findings at the type-locality and the trisselwand (schlagintweit & ebli, 1999), the jurassic–cretaceous boundary can be fixed approximately as within this ultimate marginal facies. in the following paragraphs, information on the three mentioned localities (fig. 1) is summarized, along with mention of previous works, data on biostratigraphy and the microfacies of the samples containing iberopora bodeuri. plassen near hallstatt – austrian salzkammergut: fenninger & hötzl (1967), schlagintweit et al. (2003a). at this locality, iberopora bodeuri granier & berthou (pl. 1, fig. 3) is extremely rare and has so far not been found in the platform margin facies of the high-energy labyrinthina shoals of upper kimmeridgian age. the lack of iberopora there is obviously linked to the absence of prominent coralpatches. iberopora bodeuri has been occasionally observed in bioclastic upper slope deposits (bioclastic packstones with echinoid remains) that rest on coralbearing limestones at the summit of mount plassen. the coralline facies contain foraminifera such as coscinophragma aff. cribrosa (reuss) and rarely trocholina sp. and protopeneroplis ultragranulata (gorbatchik). dasycladales are represented by anisoporella ?jurassica (endo) and terquemella ?concava bernier. from the reconstructed synoptic profile, the sample with iberopora bodeuri can be placed in the lower berriasian (for further details see schlagintweit et al., 2003a). krahstein – styrian salzkammergut of austria: flügel (1964), steiger & wurm (1980), schlagintweit et al. (2003b). the figuration of iberopora bodeuri as “red algae” from the plassen formation of the krahstein is one of the oldest references discovered in our research (pl. 1, figs. 1 and 5). it was reported by steiger & wurm (1980 – pl. 28, fig. 4) from “near-reef sparry detrital limestone (rudstone/grainstone)” containing corals, calcisponges, bryozoans and echinoid remains. according to our own investigations, these reefal debris limestones are of late kimmeridgian age (schlagintweit et al., 2003b). the samples containing i. bodeuri were collected near the summit of mount krahstein (1564 m a.s.l.) – for locality and facies map see fig. 4 in steiger & wurm (1980). we assume a “fore”-reef depositional setting for the high-energy biosparitic limestones with echinoid fragments and bryozoa containing nodules of i. bodeuri. this assumption is supported by the discovery of the microproblematicum muranella parvissima (dragastan) that, according to various authors, is typical of “fore reef” settings (radoičić, 1969: p. 75, “outer reef zone”; eliasova, 1981: “front of the reef”; dragastan & richter, 1999: fig. 8). this interpretation provides an explanation for the often observed occurrence of iberopora bodeuri in typical slope deposits (see locality trisselwand). in the coral–sponge facies it is accompanied by thalamopora lusitanica termier, neuropora lusitanica termier, the “sclerosponge” sensu koch et al. (1994), cylicopsis verticalis turnšek, murania n.sp. and most typically consinocodium japonicum endo. trisselwand near lake altaussee – austrian salzkammergut: hötzl (1966), schlagintweit & ebli (1999). at the trisselwand locality near altaussee, i. bodeuri (pl. 1, figs. 2, 4, 6; pl. 2, figs. 4–7) occurs with a rich assemblage of microencrusters typical of platform margins and commonly along with indicators of slope facies such as “tubiphytes” morronensis crescenti (pl. 1, fig. 9; pl. 2, fig. 2), terebella lapilloides fig. 1 topographic sketch map of austria showing the occurrences of iberopora bodeuri granier & berthou. 2 geologia croatica 57/1 3schlagintweit: iberopora bodeuri granier & berthou 2002 (incertae sedis)... (muenster) (pl. 1, fig. 8), mercierella? dacica dragastan, carpathiella triangulata míšík, soták & ziegler (pl. 1, fig. 7), “prism problematicum” sensu schmid (1996) (pl. 1, fig. 9) and koskinobullina socialis cherchi & schroeder. their age is latest tithonian–berriasian. here, only crustose layers of iberopora bodeuri on fragments of “reef ”-builders have been detected, not the nodular masses found at the krahstein locality. this observation, however, may simply be sampling error. besides the aforementioned microencrusters, limestones with i. bodeuri contain microbolitic crusts and also the calcareous sponges/sclerosponges with neuropora lusitanica termier, peronidella sp. and cylicopsis sp. (“sponge–coral facies”). 3. palaeontology incertae sedis genus iberopora granier & berthou 2002 iberopora bodeuri granier & berthou 2002 (pl. 1, figs. 1–6; pl. 2, figs. 4–7) 1966 codiacée crouteuse – radoičić: pl. 70, fig. 1, oxfordian/kimmeridgian of the external dinarides. 1980 red algae – steiger & wurm: pl. 28, fig. 4, plassen formation of mount krahstein. 1986 archaeolithothamnium sp. – elias & eliasova: pl. 8, tithonian stramberk limestone of the outer carpathians. 1987 “microstructure porostromate a” – granier: pl. 4, fig. a; pl. 51, figs. a–b, e, lower to middle berriasian of portugal. 1991 mikroproblematikum 1 – fürsich & werner: figs. 4e and 5h, oxfordian of portugal. 1995 “incrostazioni algali su colonie di coralli, in un boundstone” – carras: pl. 20, fig. 4, kimmeridgian–tithonian of greece. 1996 crust problematicum – schmid: p. 205, fig. 125–126, kimmeridgian of the lusitanian basin/ portugal. 1998 “krustenproblematikum” (sensu schmid, 1996) – helm & schülke: pl. 16, fig. 2, oxfordian of nw germany. 1999 “krustenproblematikum” schmid – dupraz & strasser: pl. 12, fig. 4, middle–late oxfordian of swiss jura mountains. 1999 crust problematicum schmid, 1996 – schlagintweit & ebli: p. 406, pl. 10, fig. 1, uppermost tithonian or lowermost berriasian of the plassen formation of the trisselwand, upper kimmeridgian of the krahstein (both northern calcareous alps). 2002 krustenproblematikum schmid 1996 – dupraz & strasser: p. 452 (not figured), oxfordian of the swiss jura mountains. *2002 iberopora bodeuri n.gen., n.sp. – granier & berthou: p. 121, pl. 2, figs. 2–4, lower to middle berriasian of portugal. 2003 iberopora bodeuri granier & berthou – helm et al.: pl. 1, fig. 3, oxfordian of nwgermany. 2003 iberopora bodeuri granier & berthou – uta & bucur: pl. 3, fig. 4, ?berriasian of south carpathians, romania. description the “skeleton” of iberopora bodeuri is composed of tiny bubble-like superimposed cells occurring in layers parallel to the substratum. the size of the individual cells ranges from 0.015–0.03 mm in width to 0.01– 0.02 mm in height. the cell (or chamber) wall is a thin micritic envelope; no connection whatsoever between adjacent or superimposed cells has been detected. thin sparitic layers that occur more or less regularly intercalated in the “skeleton” are a determining characteristic (e.g. pl. 1, figs. 2, 5). according to granier & berthou (2002), these “bands of calcite” reach a thickness of up to 0.05 mm. the distance between layers ranges from 0.28 to 0.4 mm. scrutiny of these “sparitic bands”, shows that they are not continuous, but are typically interrupted by small vertical intercalations of “normal” micritic cells (see for example fig. 3 in granier & berthou, 2002). characteristically, the upper part (in the direction of growth) is smooth whereas the lower part is irregular, sometimes tapering to form tooth-like shapes. it must also be noted that no sharp boundary (such as the cell wall as in sporangia of coralline algae) exists between the sparitic layers and the micritic cells. in the alpine plassen formation, iberopora bodeuri occurs as two morphotypes, one crustose, the other nodular masses. in both morphotypes, no structural differentiation, e.g. a juvenile basal or an adult stage, has been found. the crustose type when attached to larger bioclasts such as corals or “stromatoporoids” may consist of just a few cell/chamber layers (pl. 2, fig. 5) or attain thicknesses usually ranging between 0.2 and 0.4 mm (pl. 1, fig. 2). the other form of typical appearance is nodular masses, the “solenoporoid” morphotype of schlagintweit & ebli (1999). a digiform branching of the nodules (known for example from marinella lugeoni pfender, see leinfelder & werner, 1993) has not been observed. the nodules can reach sizes of up to 23 mm in width and up to 17 mm in height (pl. 1, fig. 5). the “solenoporoid morphotype” has been observed exclusively in biosparitic limestones, thus indicating water energy as an important ecofactor, its relative strength controlling 4 geologia croatica 57/1 5schlagintweit: iberopora bodeuri granier & berthou 2002 (incertae sedis)... whether growth is nodular or crustose. note, however, that the above mentioned sparitic layers occur in both the crustose and nodular morphotypes. no incrustations have been observed between cell layers of iberopora with any other microencruster except koskinobullina socialis cherchi & schroeder (see also remarks). the surface of the nodular masses, however, may show incrustations by bryozoa or foraminifera. discussion although it had been figured in the literature (see synonymy), granier (1987) and schmid (1996) were the first to pay particular attention to this microproblematicum. the latter described it from the kimmeridgian of the lusitanian basin of portugal as “crust problematicum”. schmid (1996 – p. 205) remarks on a possible relationship with red algae because of similarities with lithoporella. the red algae lithoporella, e.g. l. melobesioides (foslie) has palisade-like, subparallel cells (about 0.046x0.018 mm) forming monostromatic layers. occasionally large conceptacles (up to 0.45x0.25 mm) occur (e.g. poignant & du chaffaut, 1970; poignant, 1985). thus lithoporella differs distinctly and markedly from iberopora. some species of coralline red algae have been reported from the late jurassic (e.g. imaizumi, 1965; johnson & kaska, 1965) but several authors have expressed serious doubts with respect to the stratigraphic attribution and taxonomic relationships of these taxa (see aguirre et al., 2000). that there is obviously no thallus differentiation speaks against the assignment of iberopora to “ancestral corallines”. coralline algae are composed of rectangular cell patterns but in iberopora these cells are superimposed and do not form coaxial rows. marinella lugeoni pfender also shows no thallus differentiation. recently, the genus norithamnium under the rhodophyceae, order corallinales, was introduced by senowbari-daryan et al. (2002) from upper triassic reefal limestones. in contrast, schmid (1996) also suggests possible affinities of iberopora with the palaeozoic cyanobacteria sphaerocodium (syn.: rothpletzella), though nonseptate, fan-like arranged and branching filaments typical to sphaerocodium are lacking (see mamet, 1991 – p. 428). granier & berthou (2002) offer yet another aspect of the relationship. they note similarities with solenomeris ogormani (douville) (= acervulina ogormani acc. to moussavian & höfling, 1993), long interpreted as a solenoporacean alga, now regarded as an encrusting foraminifera (see perrin, 1992). note that the flexibility of growth in iberopora that creates either crustose layers or nodular masses is in fact also present in acervulinid foraminifera. validation of evidence for this interpretation, cautiously favoured by granier & berthou (2002), would be the identification of a juvenile stage with embryonic apparatus. as a function of alternations in growth rates, acervulina ogormani develops layers of small and flat chamberlets intercalated between larger, more rounded chambers (e.g. moussavian & höfling, 1993 – pl. 2, fig. 7). these are indeed somewhat similar to those of iberopora bodeuri. the main difference is the “wall of hyaline, optically radial calcite, coarsely perforate” of the acervulinidae (see loeblich & tappan, 1988 – p. 596). these authors state that representatives of the acervulinidae are known from palaeocene and younger strata. last but not least, helm et al. (2003) mention similarities in the structure of iberopora to those of wetheredella that may indicate a cyanobacterial origin. remarks the association with koskinobullina socialis cherchi & schroeder has been mentioned by schmid (1996), helm & schülke (1998), dupraz & strasser (1999), schlagintweit & ebli (1999) and granier & berthou (2002). it is noteworthy that the association with the latter has been observed only in the encrusting, not the nodular morphotype sensu schlagintweit & ebli (1999). this, however, can also be incidental (a sampling effect). helm & schülke (1998 – p. 86, 98), note transitions between the small chambers of koskinobullina and “krustenproblematikum” and a gradational transition between the fossil structures of both taxa. according to these authors (p. 98), “these circumstances suggest a colonial plasticity within “krustenproblematikum” (a small chambered morphotype of koskinobullina socialis)”. the totally different wall structure – calcitic hyaline and perforated in koskinobullina and microcrystalline calcitic (micritic) in iberopora bodeuri, however, contradicts such an interpretation. the co-occurrence of two discrete taxa of encrusting organisms in the upper jurassic “reefal” facies is probably due to their flourishing in the same favourable environment. accordingly, the common encrustation can be regarded as another example of biomuration as discussed by cherchi & schroeder (1985 – p. 368) for colonies of k. socialis interbedded with corallinacean algae in middle cenomanian limestones: “when the colonies are very large, the rhodophycean thalli are, in general, not able to cover the whole surface. in this case, the lateral extension of the rhodophyceans is frequently hindered by overgrowing individuals of k. socialis”. it appears most probable that the immuration of k. socialis by iberopora bodeuri follows the death of the former since it could no longer feed when totally encapsulated by the latter. for further discussion see voigt (1970) for a maastrichtian example involving a foraminifera and a worm-like organism. another point is the difference in the stratigraphic ranges of iberopora bodeuri (oxfordian–berriasian acc. to present knowledge) and that of koskinobullina socialis (bathonian to middle cenomanian, acc. to 4 geologia croatica 57/1 5schlagintweit: iberopora bodeuri granier & berthou 2002 (incertae sedis)... cherchi & schroeder, 1985). for example, in the alpine allochthonous urgonian limestones (upper barremian–albian) found in upper cretaceous conglomerates, koskinobullina socialis is a common microencruster (schlagintweit, 1991 – pl. 8, fig. 17), but iberopora bodeuri is not present in these limestones. in the alpine plassen formation, koskinobullina socialis cherchi & schroeder may again occur alone, that is not intergrown with iberopora bodeuri (pl. 2, figs. 1, 3) although the latter may be present in this fore-reef facies. palaeoecology the lithology and microfacies in which iberopora bodeuri is found, along with the associated biota, permit the following inferences regarding its palaeoecology. in the alpine plassen formation, i. bodeuri has been found in facies indicating a hard substrate: corals, stromatoporoids or calcareous sponges requiring fixation. where the platform margin-facies is represented by labyrinthina shoals as in the upper kimmeridgian of mount plassen, iberopora has not been detected. the facies in which i. bodeuri is found can be considered as seaward portions of coral-patches (“fore-reef ”) and upper slope deposits with an association of corals, stromatoporoids and calcareous sponges. also the co-occurrence of otherwise discrete microbial crusts is worth mentioning. in conclusion, i. bodeuri obviously was not as dependent on light penetration as were dasycladacean green algae (up to -20 m, e.g. masse, 1988), and furthermore it has been detected in facies where strictly photophile dasycladales are absent. where fragments of them do occur under these conditions they are to be regarded as redeposited and allochthonous. in this connection, similarities to modern cenozoic coralline algae can be drawn (e.g. adey, 1976; wray, 1979). together with other microencrusters it occurs in the so-called “tubiphytes–koskinobullina association”, typically found at the transition from shallower to deeper water facies (schmid, 1996 – p. 214). in the upper jurassic of portugal this characteristic association has been referred by schmid (1996 – fig. 143) to an inner to middle ramp environment. in nw-germany it occurs in coral reef facies and according to helm et al. (2003), i. bodeuri is a pioneer organism that avoids cryptic niches inside coral reef facies thus suggesting a certain dependence on light. in summary, the occurrence of i. bodeuri is facies-dependent and it occurs mainly in reefal (outer infralittoral) and upper slope facies (upper circalittoral – see masse, 1988). palaeogeographic distribution germany in the süntel mountains of nw-germany i. bodeuri occurs in a coral–microbialite reef of oxfordian age: the solenopora biostrome facies sensu helm & schülke (1998). this facies – a parautochthonous biostrome – occurs “above and laterally adjacent to the reef core”. here i. bodeuri is usually intergrown with koskinobullina socialis cherchi & schroeder. helm (1997) considered that early lithification of the koskinobullina socialis/“krustenproblematikum” agglomerates must be assumed because of the presence of borings in its walls. these borings also exist in the alpine material of the plassen formation. switzerland i. bodeuri was reported and figured by dupraz & strasser (1999, 2002) from the oxfordian of the switzerland jura mountains. it occurs in the so-called röschenz member that stratigraphically includes the major part of the bifurcatus zone (upper middle oxfordian) and the lowermost part of the bimammatum zone (upper oxfordian) (dupraz & strasser, 1999 – fig. 2). again, the occurrence with the enigmatic encruster koskinobullina socialis cherchi & schroeder was observed in coral–microbialite patch-reefs. although rare in this habitat when compared with the occurrence of other microencrusters – serpulids, “tubiphytes” or nubeculariid foraminifera, koskinobullina–”krustenproblematikum” occurs most frequently in framestone facies with branching corals. slovakia here, it occurs in the stramberk limestones (tithonian) of the outer flysch carpathians. it was figured by elias & eliasova (1986 – pl. 8) as archaeolithothamnium sp. these redeposited boulders came from a former reef belt with corals and calcareous algae typical of reefal/platform margin facies such as teutloporella socialis praturlon and nipponophycus ramosus yabe & toyama. iberopora bodeuri is also common in the stramberk limestones of the polish part of the outer carpathians (pers. comm. dr. b. kolodjziej, krakow). portugal schmid (1996) was the first to pay particular attention to this encrusting microfossil incertae sedis from the kimmeridgian. hesitating to introduce a new taxon, schmid (1996) called it “krustenproblematikum” (crust problematicum) and reported it as generally rare, sometimes with koskinobullina socialis in mixed coral– siliceous sponge facies and coral–microbolite facies. another occurrence is from one oncoid formed in a shallow lagoon. in the lusitanian basin it was recorded as mikroproblematikum 1 by fürsich & werner (1991). here it is associated with microbial crusts containing a diverse association of microencrusters, and coralline sponges (werner et al., 1994 – fig. 10). greece i. bodeuri was figured as “incrostazioni algali su colonie di coralli, in un boundstone” from the kimmeridgian of the “calcari di distomon” margin facies of 6 geologia croatica 57/1 7schlagintweit: iberopora bodeuri granier & berthou 2002 (incertae sedis)... the parnassos zone by carras (1995 – pl. 20, fig. 4). note also the co-occurrence with koskinobullina socialis cherchi & schroeder (carras, 1995 – pl. 19, fig. 6). these biolithites and calcirudites contain corals, ellipsactinidae, calcareous sponges, echinoids, nerineids, large dasycladales and benthic foraminifera. romania recently, i. bodeuri has been reported by uta & bucur (2003) from berriasian microbialithic limestones of the south carpathians associated with koskinobullina, radiomura and “tubiphytes” morronensis crescenti. yugoslavia another occurrence is in the vojnik mountains of the outer dinarides. radoičić (1966 – pl. lxx, fig. 1) figured an “encrusting codiaceae” that seems to belong to iberopora bodeuri but exhibits also some chambers of koskinobullina socialis cherchi & schroeder (= microproblematica pr 6, radoičić, 1966 – pl. clix, fig. 1). this occurrence is referred to as “calcaire organogèno-détritique”, that is to say presumably reefal to peri-reefal facies. detailed stratigraphic data are not available. the occurrences of iberopora bodeuri granier & berthou (see synonymy) have been plotted on a palaeogeographic map of the oxfordian adapted from stampfli et al. (1998) modified to include results from gawlick et al. (1999). the map (fig. 2) shows that this species existed on both shores of tethys. all occurrences known are in a belt of about 15 to 40º northern latitudes. 4. conclusions iberopora bodeuri granier & berthou is a microfossil incertae sedis known from limestones ranging in age from oxfordian to berriasian. these limestones were deposited in ramp or carbonate platform environments of the western tethyan domain. it is a typical facies sensitive microorganism that occurs in reefal, fore-reefal and upper slope environments where it is associated with a diverse assortment of microencrusters and metazoans (corals, stromatoporoids, and calcareous sponges). acknowledgements thanks to prof. h.-j. gawlick (univ. leoben), prof. r. lein (univ. vienna) and dr. o. ebli (c/o univ. munich) for their contribution of the thin-section material. the manuscript has kindly been read by dr. d. schmid (univ. munich). the remarks of one anonymous reviewer, dr. b. granier (paris) and the assistance with the english of dr. n.j. sander (modesto, california) are kindly acknowledged. fig. 2 occurrences of iberopora bodeuri granier & berthou in the western tethyan realm (simplified palaeogeographic reconstruction of plate boundaries based on stampfli et al., 1998, with integration of the results of gawlick et al., 1999). 6 geologia croatica 57/1 7schlagintweit: iberopora bodeuri granier & berthou 2002 (incertae sedis)... 5. references adey, w.h. (1976): crustose coralline algae as microenvironmental indicators in the tertiary.– in: gray, j. & boucot, a.j. (eds.): historical biogeography, plate tectonics and the changing environment. oregon state university press, 459–464. aguirre, j., riding, r. & braga, j.c. (2000): diversity of coralline red algae: origination and extinction patterns from the early cretaceous to the pleistocene.– paleobiology, 26/4, 651–667, lawrence. böhm, f. (1992): mikrofazies und ablagerungsmilieu des lias und dogger der nordöstlichen kalkalpen [microfacies and depositional environment of lias and dogger of the northeastern calcareous alps – in german].– erlanger geol. abh., 121, 55–217, erlangen. carras, n. (1995): la piattaforma carbonatica del parnasso durante il giurassico superiore–cretaceo inferiore [the carbonate platform of the parnassos during the upper jurassic–lower cretaceous – in greek with italian abstract].– unpubl. phd thesis, university of athens, 232 p. cherchi, a. & schroeder, r. (1985): koskinobullina socialis cherchi & schroeder, 1979: a colonial microfossil incertae sedis (algae?) from jurassic–cretaceous of the mediterranean region.– boll. soc. paleont. ital., 23/2, 361–374. dragastan, o. & richter, d.k. (1999): late jurassic oolites from the acrocorinth (ne-peleponnesus): calcareous micro-algae as an exceptional paleoecologic indicator.– bochumer geol. geotechn. arb., 53, 149–172. dupraz, c. & strasser, a. (1999): microbialites and micro-encrusters in shallow coral bioherms (middle to late oxfordian, swiss jura mountains).– facies, 40, 101–130. dupraz, c. & strasser, a. (2002): nutritional modes in coral–microbialite reefs (jurassic, oxfordian, switzerland): evolution of trophic strcture as a response to environmental change.– palaios, 17, 449–471. elias, m. & eliasova, h. (1986): elevation facies of the malm in moravia.– geol. zborn. – geol. carpathica, 37/4, 533–550. eliasova, h. (1981): some binding microorganisms of the stramberk reef limestones (tithonian, czechoslovakia).– véstnik ustr. ustav. geol., 56/1, 27–31, prag. fenninger, a. & hötzl, h. (1967): die mikrofauna und -flora des plassenund tressensteinkalkes der typlokalität (nördliche kalkalpen) [microfauna and -flora of the plassen and tressenstein limestones of the type-localities, northern calcareous alps – in german].– n. jb. geol. paläont. abh., 128/1, 1–37. flügel, e. (1964): ein neues vorkommen von plassenkalk (ober-jura) im steirischen salzkammergut, österreich [a new occurrence of plassen limestone, upper jurassic, in the styrian salzkammergut, austria – in german].– n. jb. geol. paläont. abh., 120/2, 213–232. frisch, w. & gawlick, h.-j. (2003): the nappe structure of the central northern calcareous alps and its disintegration during miocene tectonic extrusion – a contribution to understanding the orogenic evolution of the eastern alps.– int. journ. earth. sci., 92, 712–727. fürsich, f.t. & werner, w. (1991): paleoecology of coralline sponge–coral meadows from the upper jurassic of portugal.– paläont. z., 65/1–2, 35–69. gawlick, h.-j. (2000): die radiolaritbecken in den nördlichen kalkalpen (hoher mittel-jura, ober-jura) [the radiolarite basins in the northern calcareous alps, upper middle jurassic, upper jurassic – in german].– mitt. ges. geol. bergbaustud. österr., 44, 97–156. gawlick, h.-j., frisch, w., vecsei, a., steiger, t. & böhm, f. (1999): the change from rifting to thrusting in the northern calcareous alps as recorded in jurassic sediments.– geol. rdsch., 87, 644–657. granier, b. (1987) : le crétacé inférieur de la costa blanca entre busot et altea (alicante, espagne): biostratigraphie, sédimentologie, évolution tectono-sédimentaire [the lower cretaceous of the costa blanca between busot and altea, alicante area, spain: biostratigraphy, sedimentology, tectono-sedimentary evolution – in french].– unpubl. phd thesis, univ. pierre et marie curie, paris, 281 p. granier, b. & berthou, p-y. (2002): algues calcaires fossiles, nouvelles ou peu connues, du portugal. 1ere partie [new or poorly known fossil calcareous algae of portugal. part i – in french].– in : bucur, i.i. & filipescu, s. (eds.): research advances in calcareous algae and microbial carbonates. proc. 4th ifaa reg. meet. cluj–napoca, august 29–september 5, 2001, 117– 126, cluj university press. helm, c. (1997) : faunistische untersuchungen an einem fleckenriff des oberjura (florigemma-bank; süntel) [faunistical investigations of an upper jurassic patch-reef, florigemma-bank, süntel – in german].– unpubl. m.sc. thesis, university of hannover, 105 p. helm, c. & schülke, i. (1998): a coral–microbialite patch reef from the late jurassic (florigemma-bank, oxfordian) of nw germany (süntel mountains).– facies, 39, 75–104. helm, c., schülke, i. & schlagintweit, f. (2003): calcareous algae (“porostromata”, rhodophyta, dasycladales) and microproblematica with algal affinity from the nw german korallenoolith formation (oxfordian, süntel mountains).– facies, 49, 61–86. hötzl, h. (1966): zur kenntnis der tressenstein-kalke (ober-jura, nördliche kalkalpen) [on the knowledge of the tressenstein limestones, upper jurassic, northern calcareous alps – in german].– n. jb. geol. paläont. abh., 123/3, 281–310. imaizumi, r. (1965): late jurassic algae from honshu and shikoku, japan.– sci. rep. tohoku univ., 2nd ser. (geol.), 37/1, 49–62. johnson, j.h. & kaska, h.v. (1965): fossil algae from guatemala.– prof. contrib. colorado school of mines, 1, 152 p., golden. koch, r., senowbari-daryan, b. & strauss, h. (1994): the late jurassic “massenkalk-fazies” of southern germany: calcareous sand piles rather than organic reefs.– facies, 31, 179–208. 8 geologia croatica 57/1 9schlagintweit: iberopora bodeuri granier & berthou 2002 (incertae sedis)... leinfelder, r.r. & werner, w. (1993): systematic position and palaeoecology of the upper jurassic to tertiary alga marinella lugeoni pfender.– zitteliana, 20 (hagn/herm–festschrift), 105–122. leinfelder, r.r., nose, m., schmid, d.u. & werner, w. (1993): microbial crusts of the late jurassic: composition, palaeoecological significance and importance in reef construction.– facies, 29, 195–230. loeblich, a.r. & tappan, h. (1988): foraminiferal genera and their classification.– van nostrand reinhold, new york, 970 p. (two vols.). mamet, b. (1991): carboniferous calcareous algae.– in: riding, r. (ed.): calcareous algae and stromatolites. springer verlag, berlin, 370–451. mandl, g.w. (2000): the alpine sector of the tethyan shelf – examples of triassic to jurassic sedimentation and deformation from the northern calcareous alps.– mitt. österr. geol. ges., 92, 61–77. masse, j.-p. (1988): l’étage bionomique des milieux benthiques néritiques actuels: signification bathymétrique et implications paléobathymétriques (the vertical bionomic zonation of modern benthic neritic environments: bathymetric significance and palaeobathymetric implications).– géologie méditerranéenne, 15/1, 91–102. moussavian, e. & höfling, r. (1993): taxonomische position und palökologie von solenomeris douville, 1924 und ihre beziehung zu acervulina schultze, 1854 and gypsina carter, 1877 (acervulinidae, foraminiferida) [taxonomic position and paleoecology of solenomeris douville, 1924 and its relationships to acervulina schultze, 1854 and gypsina carter, 1877, acervulinidae, foraminifera – in german].– zitteliana, 20, 263–276. perrin, c. (1992): ecological significance of paleocene to recent acervulinid foraminifera, their contribution to reef construction and other biogenic facies.– géobios, 25/6, 725–751. poignant, a.-f. (1985): présentation simplifiée d´une nouvelle classification génerique des rhodophycées mésozoiques et cénozoiques. informatisation [simplified introduction of a new generic classification of mesozoic and cenozoic rhodophyceae. computerization – in french].– bull. soc. géol. france, 1985, (8), i/4, 603–605. poignant, a.-f. & du chaffaut, s.a. (1970): les algues des formations transgressives maestrichtiennes, paléocènes et yprésiennes de la cote sud-orientale de la corse [maastrichtian, paleocene and ypresian algae from transgressive formations of the southeastern coast of corsica – in french].– rev. micropaléont., 12/4, 202–208, paris. radoičić, r. (1966): microfacies du jurassique des dinarides externes de la yougoslavia [jurassic microfacies of the external dinarids of jugoslavia – in french].– geol. transact. rep. – razprave in poročila, 9, 5–377, ljubljana. schlagintweit, f. (1991): allochthone urgonkalke im mittleren abschnitt der nördlichen kalkalpen: fazies, paläontologie und paläogeographie [allochthonous urgonian limestones in the middle part of the northern calcareous alps: facies, palaeontology and palaeogeography – in german].– münchner geowiss. abh., (a), 20, 1–120. schlagintweit, f. & ebli, o. (1999): new results on microfacies, biostratigraphy and sedimentology of late jurassic–early cretaceous platform carbonates of the northern calcareous alps. part i: tressenstein limestone, plassen formation.– jb. geol. b.–a., 56/2, 379–418, wien. schlagintweit, f., gawlick, h.-j. & lein, r. (2003a): die plassen-formation der typlokalität (salzkammergut, österreich) – neue daten zur fazies, sedimentologie und stratigraphie [the plassen formation of the type-locality, salzkammergut, austria – new data on facies, sedimentology and stratigraphy – in german].– mitt. ges. geol. bergbaustud. österr., 46, 1–34. schlagintweit, f., gawlick, h.-j., ebli, o., rünstler, h. & suzuki, h. (2003b): die plassen-formation (kimmeridgium) des krahstein, steirisches salzkammergut und deren unterlagerung: neue daten zur fazies, biostratigraphie und sedimentologie [the plassen formation, kimmeridgian, of the krahstein, styrian salzkammergut, and its basement: new data on facies, biostratigraphy and sedimentology – in german].– in: weidinger, j.t., lobitzer, h. & spitzbart, i. (eds.): beiträge zur geologie des salzkammergutes. gmundner geo-studien, 2, 87–96, gmunden. schmid, d.u. (1996): marine mikrobolithe und mikroinkrustierer aus dem oberjura [marine microbolites and micro-encrusters from the upper jurassic – in german].– profil, 9, 101–251, stuttgart. senowbari-daryan, b., keupp, h., abate, b. & vartis-matarangas, m. (2002): first record of norithamnium gen. nov. (corallinales, rhodophyta) from late triassic (norian–rhaetian) reefs of the western tethys.– in: bucur, i.i. & filipescu, s. (eds.): research advances in calcareous algae and microbial carbonates. proc. 4th ifaa reg. meet. cluj–napoca, august 29–september 5, 2001, 201–208, cluj university press. stampfli, g.m., mosar, j., marquer, d., marchant, r., baudin, t. & borel, g. (1998): subduction and obduction processes in the swiss alps.– tectonophysics, 296, 159–204. steiger, t. & wurm, d. (1980): faziesmuster oberjurassischer plattform-karbonate (plassenkalke, nördliche kalkalpen, steirisches salzkammergut, österreich) [facies patterns of upper jurassic platform carbonates, plassen limestone, northern alps, styria/austria – in german].– facies, 2, 241–284. tollmann, a. (1985): geologie von österreich, band 2 [geology of austria, volume 2 – in german].– deuticke, wien, 710 p. tollmann, a. (1987): late jurassic/neocomian gravitational tectonics in the northern calcareous alps in austria.– in: flügel, h.w. & faupl, p. (eds.): geodynamics of the eastern alps. deuticke, wien, 112–125. uta, a. & bucur, i.i. (2003): microbial structures and microencrusters in the upper jurassic–lower cretaceous deposits from buila–vanturarita massif (south carpathians).– studia universitatis babes–bolyai, geologia, xlviii/2, 3–14, cluj–napoca. 8 geologia croatica 57/1 9schlagintweit: iberopora bodeuri granier & berthou 2002 (incertae sedis)... voigt, e. (1970): foraminiferen und (?) phoronidea als kommensalen auf den hartgründen der maastrichter tuffkreide [foraminifera and (?)phoronidea as commensalists in the hardgrounds of the maastrichtian tuffkreide – in german].– paläont. z., 44/1–2, 86–92. wegerer, e., suzuki, h. & gawlick, h.-j. (2003): zur stratigraphischen einstufung von kieselsedimenten südöstlich des plassen (nördliche kalkalpen, österreich) [stratigraphy of cherty sediments southeast of the plassen, northern calcareous alps, austria – in german].– jb. geol. b.-a., 143/1, 79–91. werner, w., leinfelder, r.r., fürsich, f.t. & krautter, m. (1994): comparative palaeoecology of marly coralline–sponge-bearing reefal associations from the kimmeridgian (upper jurassic) of portugal and southwestern germany.– cour. forsch.-inst. senckenberg, 172, 381–397. wray, j.l. (1979): paleoenvironmental reconstructions using benthic calcareous algae.– bull. cent. rech. explor.-prod. elf-aquitaine, 3/2, 873–879. manuscript received may 23, 2003. revised manuscript accepted may 04, 2004. 10 geologia croatica 57/1 11 plate 1 iberopora bodeuri granier & berthou and some associated microencrusters from the plassen formation of the northern calcareous alps 1, 5 nodular (solenoporoid) morphotype of iberopora bodeuri granier & berthou. locality krahstein, styrian salzkammergut; (upper) kimmeridgian, scale bar = 2 mm. sample krah–118. 2–4, 6 crustose (corallinoid) morphotype of iberopora bodeuri granier & berthou. note the intergrowth with koskinobullina socialis cherchi & schroeder (fig. 6). 2, 4, 6: locality trisselwand near altaussee (samples tk 15–1, tk 22), lower berriasian; 3: locality plassen near hallstatt (sample pl 98), uppermost tithonian or lowermost berriasian; scale bar = 1 mm for figs. 2, 3 and 0.5 mm for figs. 4, 6. 7 serpulid worm tube carpathiella triangulata míšík, soták & ziegler 1999, cross-section. locality: trisselwand near altaussee (sample tk 15–2); lower berriasian, scale bar = 0.5 mm. 8 agglutinating polychaete, probably terebella lapilloides muenster, longitudinal section. locality: trisselwand near altaussee (sample tk 15-1); lower berriasian, scale bar = 0.5 mm. 9 “prismenproblematikum” schmid 1996 (1), section of “tubiphytes” morronensis crescenti (2) and nubecularid foraminifera (3). locality: trisselwand near altaussee (tk 2); lower berriasian, scale bar = 0.5 mm. 10 geologia croatica 57/1 11 1 2 87 6 5 43 9 schlagintweit plate 1 12 geologia croatica 57/1 13 plate 2 iberopora bodeuri granier & berthou, associated microencrusters and microfacies from the plassen formation of the northern calcareous alps 1, 3 colonial microproblematicum koskinobullina socialis cherchi & schroeder encrusting a stromatoporoid. trisselwand near altaussee (tk 2); (lower) berriasian, scale bar = 2 mm in fig. 1 and 0.5 mm in fig. 3. 2 longitudinal section of “tubiphytes” morronensis crescenti. trisselwand near altaussee (tk 2); (lower) berriasian, scale bar = 1 mm. 4, 7 iberopora bodeuri granier & berthou together with encrusting foraminifera and irregular dome-shaped microbial crust. trisselwand near altaussee (tk 15–1); (lower) berriasian, scale bar = 0.5 mm in fig. 4 and 2 mm in fig. 7. 5 thin crust of iberopora bodeuri granier & berthou (right side) on spongiomorpha asiatica yabe & sugiyama. trisselwand (tk 22); (lower) berriasian, scale bar = 2 mm. 6 fragment of iberopora bodeuri granier & berthou. trisselwand (tk 22); (lower) berriasian, scale bar = 0.5 mm. 12 geologia croatica 57/1 13 1 2 76 54 3 schlagintweit plate 2 14 geologia croatica 57/1 geol. croat. 1 51/2 1 195 204 1 5 figs. 1 3 tabs. 1 1 zagreb 1998 recommendations for landslide hazard and risk mapping in croatia snjezana mihalic key words: gcohazards, landslides, landslide hazard, lands lide risk, hazard and risk mapping, gis. abstract the preparation of landslide hazard and risk maps is required as a base for rational land lise planning and decision-mak ing, in landslide prone arcas. in this paper, an inventory was made of the currently available methods for landslide hazard and fisk zonation, in order 10 produce recommendations for the lise of specific methods in relation to lhe sca le of analysis . a hierarchical sct of activities aimed at obtaining landslide-related information for all levels of land use plan­ ning in the republic of croatia is conslrllclcd. thi s sel encompasses: the establishmen t of a national landslide inventory on a regional scale « 1: 100,(00), stati stical landslide hazard analysis of geological-mor­ pholog ical fac tors at the medium scale (i :25,000) and the geotcchni­ cal c haracteri sation of slope movements followed by landslide ri sk analysis on a dctailed scale (> 1 : 5 ,(00). 1. introduction the term landslide denotes the movement of a mass of rock, debris or earth down a slope (crud en, 199 1). most of the terrain in hillside areas has been subjected to landslides at least once under the influence of a vari­ ety of causal factors . the number of slope instability is significantly increased due to urbanisation and develop­ ment in landslide-prone areas. i-tcnce, landslides conti­ nue to be one of the most threatening and widespread geohazards. there is an increasing trend for geohazards to be recognised in planning legislation and gu idance, espe­ cially in the last decade (the international decade for natural disaster reduction). many countries presently have specific planning or development policies aimed to reduce the losses due to natural hazards (schus ­ ter, 1991; mcinnes, 1996). methods vary from gui­ dance documentat ion alone, through mandatory build­ ing codes and finally to insurance or disaster relief schemes (statiiam et al. . 1995). zoning and subd ivi­ sion ordinances are used to divert development into areas where the risks are less and to ensure that , where deve lopments are permitted, the appropriate engineer­ ing measures are incorporated, faculty of mining, geology and petroleum engineering, university of zagreb, pierotlijcva 6, hr-j 0000 zagreb, croatia. risk assessment is a prerequisite for all the methods of hazard prevention and mitigation. it consists of three steps: (1) hazard assessment identification of past/pre­ sent landslides as well as the prediction of future occur­ rences; (2) vulnerability analysis identification of the location and distribution of population, infrastructure and vital economic activities exposed to a potential or present land slide; and (3) calculation of the expected loss (risk) from the hazard and vulnerability. hazard analysis requires a detailed knowledge of the geoenvi­ ronmental predisposition factors and initiation events that lead to landsliding. this lies within the domain of earth scientists. vulnerability and risk evaluation also includes other disciplines, such as urban planning, social geography, economy, etc. the end result of haz­ ard and risk analysis should be presented in informative documents, usually in the form of various maps which display the spatial distribution of hazard and risk clas­ ses, these documents are used by decision-makers who have to define a general risk prevention policy, many methods and techniques have been proposed for landslide hazard and risk mapping over the last 30 years (brabb. 1984; i'iansen, 1987; mihalic. [996), significant progress has been made by establish­ ing the basic definition of terms related to hazard and risk assessment (varnes. 1984). van westen's (1993) overview of the available methods is of great importance for improving the quality, as well as for achieving a uniform approach to landslide hazard map­ ping on an international level. on the other hand, exam­ ples of landslide risk zonations are st ill rare because of the difficulties in assessing the probability of landslid­ ing and of the vulnerability of elements at risk. howev­ er, the evaluation of risk corresponds to a political, eco­ nomic and social necessity. therefore, research of oper­ at ional risk evaluation methods is in progress (rago­ zin. 1994; rezig et ai., 1996). the first fundamental step of hazard and risk assess­ ment is the identification and mapping of all landslide phenomena, i.e. compilation of the landslide inventory (fernandez et al.. 1996; rosenbaum & popes­ cu, 1996). collection and management of spatial data req uire the utilisation of geographic inform ation sys­ tem s (gis). furthermore, the cartographic landslide data bases should be va lid nation-wide in order to ena­ ble extrapolati on of acquired experience to areas with similar characteristics (leroi, 1996). in many coun­ tries, the development of such databases started in the 196 1990's. the most important arc examples from france (leroi, 1996), germany (poschlnger , 1994; krauter et ai., 1996), the usa (brown, 1992) and canada (cruden, 1996). moreover, there is a tendency towards establi shment of a world landslide inventory (brown et ai., 1992). to ensure the consis­ tcncy of data recording, the international geotechnical societies' unesco working party on world land­ slidc invcntory (wp/wll), initiated in the 1988 at the 51h internat ional symposium on landsl ides, is suggest­ ing a standard terminology for describing landslides (wp/wll, 1993). gis technology is also essential for assembling the hazard and risk models, as well as for an efficient and rapid information exchange between sci­ entists, engineers, policy makers, and all the people and institutions dealing with the landslide hazard. before slarti ng any data collection, a number of interrelated things should be clearly defined, such as the aim of a study, the scale and degree of precision of the prescnted rcsults, and the available resources in the form of money and manpower. to achieve the optimi­ sation of costs and quality, the application of different data analysis methods at various scales is required. accordingly, a concisc rcview of current methods of landslide hazard and risk assessment is presented in this paper. the review is aimed at a comparison of the me­ thods, and proposit ion of a logical set or activities relat­ ed to the preparation and im plementation of hazard and risk maps, in the field of land use planning in the repu­ blic of croatia. this set comprises all levels of urban planning, from national to the local scale. 2. landslide hazard and risk the terminology concerning hazards and risk used in this paper conforms to the definitions proposed by varnes (1984). evaluation of various ri sk compo­ nents (hazard, vulnerability, cost) , and of the landslide risk as a whole, presupposes that answers are available 1'01' the questions as shown in table 1 (leroi, 1996). accordingly, landslide research aimed at hazard and risk mapping comprises the aspects of landslides sum­ marised in the following paragraphs. since the term of landsliding encompasses "all movement of a mass of rock, debris or earth down a component question hazard 1) which type of movement is involved? 2) where are the potentially unstable areas? geologia croalic;) 51n slope" (cruden, 1991), which types of movement arc present in the stud ied area should be defined. the types of movement arc essentially those defined by the inter­ national geotechnical societies' unesco working party on world landslide inventory: fall, topple, slide, spread and flow (cruden & varnes, 1996). location of the unstable areas should be determined by the engineeri ng geo log ical mapping of the land­ slides. the objective would bc to record identifi able landslide features and their dimensions (iaeg com­ mission on landslides, 1990). evaluation of the probabili ty or timing of the future occurrence is dependent on the probability of occur­ rence of the triggering factor. a trigger is an external stimulus, such as intense rainfall, that causes a near­ immediate response in the form of a landslide by rapid­ ly increasing the stresses or by reducing the strength of slope material (wieczorek, 1996). hence, it is of primary importance to differentiate the conditions that caused s lope instability from the processes that trig­ gered the movement (popescu, 1994). landsliding causes damage both in the areas of instability initiation and in the areas of transport and of the reception of thc movements. in order to be able to describe where the landslide is moving, it is necessary to investigate it's activity. the unesco working party on world landslide inventory (1993) suggests describing the landslidc activity ill terms relating to state, distribution and style of activity. the assessment of losses consists of analysis of the interactions between the phenomenon and goods, i. e. behaviour of structures and people that are exposed to landsliding. hence, it is fundamental to determine thc level of intcnsity of a potential phenomenon. an impor­ tant characterist ic of the movement comprised in the intensity analysis is the rate of jandsliding (lugs wg/l, 1995). 3. methods of landslide hazard zonation all the methods proposed are founded upon a single principle "the past and present are keys to the future" which implies that slope-failures in the future will be more likely to occur under those condit ions which led 3) at which moment can the identified phenomenon be triggered? vulnerability cost 4) how far can the phenomenon be propagated? 5) what are the interactions with the environment, natural or modified by man? 6) what is the cost of the resulting damage? table [ risk components with ques­ tions connected to landslide risk assessment. mih:llic ; rccommcndalions for land~ l ide i-ia;wrd and risk mapping in eroalia van westen, 1996 leroi, 1996 heuristic approach expert evaluati on stati stical approach statistical return analysis deterministic approach mechanical models table 2 methods of landslide hazard zonation. to post onci present instability (carrara et ai., 1995) . application o f the above principle requires mapping both the landslides and a se t of geological -morphologi­ cal causal fac tors, and cstabl ishment of a hazard modcl. there arc three main approaches for the developing of hazard models : heuristic, statistica l and determini stic approach. each o f them is based on different e lements as shown in table 2. 3.1. heu ristic approach in heuristic methods the expert opinion of the engi­ neering geolog ist and/or geomorpholog ist is used to classify the hazard. two types of heuristic analysis can be di stingui shed: geomorphic analysis and qualitative map combination. the gcomorph ic method is also known as the direct mopping method (hansen, 1987). it consists or geo­ morpholog ical and/or engineering geol ogical mapping through wh ich the surveyor identifies pas t and present landsl ides and makes assumptions on those sites where failures are likely to occur in the future. direct hazard de tcrm ination is based on indi vidua l experi ence. the dec ision rules vary from place to place and are difficult to form ulate. in addition, the resulting documents gen­ erally are "paper" ones (kien holz, 1978). to overcome the problem of the " hidden ru les" in di rect mappi ng, indirect mappi ng methods have been developed. qualitat ive map comb ina ti on is based on a priori knowl edge o f the cau ses of landsliding in the in ves tigated area. hence, instability factors arc ranked and we ighted according to their assumed or expected importance in caus ing a mass-movement. in this meth­ od the expert 's knowledge can be formali sed into rules, but the res ult essent ially depends on the experience of the surveyor. at present , maps obtained by th is method canno t readil y be evaluated in terms of reli ability or certainty. 3.2. statistical approac h in the statis tical approach, causal factors arc dcfi ned a posteriori, through back analysis of historical events. therefore, the ro le o f each factor (that led to landslides in the past) is de termined on the basis o f the observed re lations with th e past/present land slide di stribut ion. the sta tist ical approach can be applied foll owi ng differ­ ent techniques which essentia lly differ on the statistical procedure used: bivariate or multi variate analysis. 197 in bivariate stat istical analysis each instabili ty fac tor map is combined with a landslide distribution map, and weighting values based on landslide densit ies are calcu­ laled (siddle ct ai. , 1991; van westen, 1993; yin , 1994). mul tivariate statistical analys is of the important fac­ lars re lated to landslide occurrence, g ive the re lative contribution of each of these fac tors to the total hazard within a defined land unit. for each sampling unit, the prcsence or absence of landslides is also de termined. the model is conceptually rai rl y simple, but large data se ts arc needed to obtain cnough cases to produce rcli ­ able resuits (carrara et ai. , 1995). 3.3. determinist ic approach there are some examples of landslide hazard asses­ sment by calculating safe ty fac tors over large areas (van westen, 1993; lerol , 1996). the resulting safe ty fac tors are only indi cat ive and are used to tes t multipl e scenarios based on variable triggering hypo­ theses. the most frequently co nsidered are hydrau lic and seismic triggers. the ma in problem with these me­ thods lies in the choice o f the representative input para­ meters and the slope stability model. for the rational consideration of the natural va ri ab i­ li ty and uncertainty o f each input variable in slope sta­ bility analyses , a probabili s ti c approach is essenti al (hammond et ai. , 1992; ter lien et ai. , 1995). the objecti ve is to obtain the probabili ty distribution of the fac to r of safe ty and hence probability o f failure. the most important limitation to the application of proba­ bilistic methods in landslide hazard assessment may be the lack o f statistical data on soil properties, pore water pressures and on loads (chowdhury, 1984). 4. la ndslide risk assessment landslide risk assessment requi res the understand­ ing, analysis and control o r damage which are the con­ sequences of thc interac ti on between slope movement s and exposed element s (property, people and various activ ities). however, due to the complexity of the phe­ nomena and partly to an absence o f conceptual know­ ledge of certain risk components, a unified approach 10 the problem docs not exist. as a result of technical and sociological advances several researchers and organi sa­ tions sta rt ed to develop a me th odo logy for landsl ide risk evaluati on in the last decade (fell, 1994; rago­ zin, 1994; leone et a i. , 1996; leroueil e t ai. , j 996). anderson 's et al. ( 1996) proposa l of a risk­ based meth od for selecting alte rn atives for lands lide risk mitigation is presented as follows. the proposal is in teres ting because it comprises the whole procedure: the ident ification of risk, the estimation of risk, and the evaluat ion of risk through either avers ion or acceptance (fig . i). ri sk identification involves development o r 198 geologia croalic:t 51/2 initiating system outcome exposure consequences event response freeze-thaw action debris slide mobilize debris tim e of day rapid snowmelt debris flow complete failure prox. to failure property damage identification earthquake rockslide partial failure wamingtimc loss of revenue (examples) extreme precipitation rockfall discrete boulders time of year loss of life ---------event system outcome exposure expected ~ response r------~ f----. losses pee) p(fi e) p(o i f) p(l i 0) p(c i l) estimation i remove zidc debris warning 1ystems i ------------0 weather stabilize slide rockfall barricade modification relocate road i select ri sk aversion i m",o" .~ --------------------------------acceptance ri sk acceptance crlterion met? -ryes fig. i framework model fo r ri sk-based method to mitigate lands li des (an derson ct al" 1996). the risk model for the evaluation of an ex isti ng land­ s lid e risk. in orde r to achieve thi s it is necessary to recognise and list the va ri ous factors whi ch could con ­ tribute to the landslide failure risk, and then 10 organise these into logical event sequences. the model is organi­ sed in the foml of an event tree, which commences with events that can in itiate fai lure, and ends with the conse­ quences or a ra il ure (fig. 2). in the later phase the risk model serves fo r evaluat ion of the effectiveness of pro­ posed rehab ilit at ion alt ernati ves . the second step involves ri sk es timation, i.c. ass igning the probabi li ties and consequences to the occurrence of each fail ure mode. if these risks arc unacceptable, lhe assessment proceeds to the third step ri sk avers ion. this involves the formulation and evaluat ion of remedial act ion (reha­ bilitat ion) alternatives. the final step in the risk assess­ ment process is the decision 0 11 what degree of safety is acceptable. a crucial stage fo r a good understanding of slope movements and the risk associated with them, is the characterisation of movement through fac tors havi ng a mechanical significance. it requ ires establishing a re lationship betwccn the charac teristics of a g iven move­ me nt , ex istence of defini te predi spos iti on fac to rs, occurrence of tr iggering or aggrava ti ng fac to rs , ex is­ tence of de fin ite revea li ng fac ia l's, and of the conse­ qucnccs of the movement. for this purpose, vaunat et al. ( 1994) arc developing geotechnical characterisa­ ti on o r s lope movements, taki ng int o accou nt slope movement type, involved materia l and movemenl sta­ ges. such a characterisation constitutes an essential step fo r the development of expert systems on s lope engi­ neering, for the selection of numeri cal models fo r the simulati on of spec ifi c aspects of slope behav iour, as well as ror the design of remed ial measures for stabi lis­ ing a slope. 5. scale-related recommendations not all the methods of landslide hazard zonati on are equally applicable at each scale of analys is, because of the d ifterence in requi red input data and degree of pre­ cision o r the obtained results. table 3 provides an over­ view of the var ious methods o r landslide hazard analyinitiating event system response outcome exposure consequences rapid snowmelt... extreme precipitation freeze-thaw action ... rockslide rockfall .. partial failure com iete failure ... discrete boulders ... off-season ni hi... off-season da . tourist season night... tourist season da road closed car i-lils debris debris hits car debris kills motorist fi g. 2 hypothetical event tree branch for evaluating outcome probability for landslide ri sk assessment (anderson et ai., 1996). mihalic: recommcndalions for i_'l.nds lidc hazard and risk mapping in cro<llia 199 scale of use recommended type of ana lysis technique regional medium large «1:100,000) (1 : 25,000 -1 : 50,000) (1:5000-1 :10,000) geomorphological yes yes ' yes' analysis heuristic analysis qualitative map yes" yes ' no combination bivariate statistical no yes no statistical analysis analysis multivariate statistical no analysis yes no deterministic analysis safety factor analysis no no yes'" but strongly supported by other more quantitative techniques to obtain an acceptable level of objectivity. but only if sufficient reliable data exist on the spatial distribution of the landslide controlling factors. but only under homogeneous terrain conditions, considering the-variability of the geotechnical parameters. table 3. hazard analysis techniques in relat ion to mapping scales (soeters & van westen, 1996). sis and recommendations ror their use at the three most relevant scales. from consideration of the advantages and pitfalls or landslide hazard zonat ion techn iques, it follows that the best scale for landslide hazard mapping is the medium sca le, i.e. 1: 25 ,000. at thi s sca le it is poss ib lc to obtain an overv iew of the hazard in its entirety, at a reasonable cost. regardless of the scale at which the hazard is evalu­ ated, the risk maps shou ld be drawn at scales above i: 5,000. this is due to the impossibili ty of acquisition of required input data at smaller scales. the main field of applicat ion for landslide hazard and risk maps concerns land use planning, development and regulations. hence, hazard and ri sk zonation has to comprise all levels of land use planning. to obtain an acceptable cost/benefit ra ti o and to ensure the practical applicability of the zonation , the development of a clear hierarchical methodology for the structuring and analy­ sis of data is necessary. 5.1. application to croatia regional and medium scale landsl ide hazard map­ ping has never bee n undert aken in the republic of croatia. there are some exampl es of landslide hazard analyses at large and deta iled scales, aimed at urban planning of particular areas. there is no experience of landslide risk assessment in croatia. slope stability catego ri sations for thc zagrcb city area have been undcrtaken twice. tn 1979 the lithologi­ cal classification and s lope stabi lity categorisat ion was produced, and in 1988 categorisation were made in the framework of the seismic microzonation of zagreb city. in both cases the methods of direct mapping were applied, and the derived maps are at the 1: 10,000 scale. both of these maps arc sti ll relevant for urban develop­ ment in zagreb. moreover, the map of lithological clas­ s ifi cation and s lope stability categorisation of the mi. medvedniea hi llsides is part or the legislative document thc physical plan of thc zagreb city. the drawback of these maps is the outdated data, as we ll as in the applied assessment method, because the criteria of eval­ uation are not clearly defined. at the level of detailed physieal development plans (le. on a large scale) it is common to perform the geo­ techn ical slope stabilit y ana lys is wit h the definit ion of construction conditions accordi ng to the planned land usc. this could prove rational onl y for small areas, i.e. < 100 ha (stanic & mihalic, 1995). in respect of the fact that cons ideration of instabi lity in the planning processes in croatia is onl y parti al, and thus unsatisrac tory (mihalic & stantc, 1995), the proposal of a logical set of activit ies connected 10 the hazard and risk mapp ing was constructed which com­ pri ses all the levels o r urban plann ing. the proposal is presented in the framework of recommendation [or the application to urban planning documents cu rrently valid in the republic of croati a with special emphasis to the territory or zagreb city. these rccom mendati ons are applicable at three levcls (fig. 3): i) at the regional seale ( i: 100,000 or smaller) the national landslide inventory should be made. the obje­ ctive of the inventory is 10 provide an ins ight into the spatia l distribution of landslides in croatia. it is also poss ibl e to analyse lands lid e density. although the method does not enable the production of a landsl id e hazard map. the quantitative presentation of landslide density would indicate areas in croatia where mass movement s ca n be a constraint to development. the information obtained should serve [or physical planning at the national and county level. overlaying of a land­ slide distribution map with the n1aps which display cle­ ments at ri sk (i.e. land use map) should also indi catc areas where landslide hazard mapping is necessary. additionally, the records of the most significant land 200 regional scale < i :100,000 la ndslide inve ntory i landslide distribution analysis: , lan dsli des i i elements at rl~)_:<~= .~<>'<-~~-~' medium scale t :25,000 statistical hazard analysis of geological-morphological factors hazard map i elements at rrsk / r ~ _ _ _ _____ _ _ _ _ _______________ _ _ _ ____ _ , , detaile d scale : > 1:5000 , geotechnical characterisations of slope , movement & risk analysis , i landslides i ) risk l\'1a p ~ ~ l , , , , , : , , , , , , , -----------------~ geologia croalicl 5 in fig. 3 hierarchical mo ­ del for landslide ha­ za rd and risk map­ ping. slides in croatia could also serve as input for the world landslide inventory. of the basic engineering geological map of the rcpub­ lic of croatia scale i: 100,000. figure 4 is a cartogra­ phic representation of a landslide inventory in the cen­ tral part of the zagreb section. the croatian institute of geology is currently deve­ loping a lands lide inventory as part of the preparation fig. 4 landslide inventory map of the central part of zagreb section (engi ­ neering geo ­ logi cal data base in stitu ­ te of gcology, zagreb). mih:llic: recommendations for lmdslidc hazard and rhk m:lpping in croatia 2) at the medium scale (i : 25,000) sta ti stical hazard analys is of geolog ical-morphological causal factors is requ ired. the detail on the hazard map should be such, that adjacent slopes of the same lithology are evaluated separately, and may obta in different hazard scores, depending on other characterist ics, such as slope angle and slope segments. this map should represent a base for rational land-usc planning, in order to locale devel­ opmen ts on stable ground. the fie ld of app li cation would be the physical planning at the municipal and ci ty level. accordingly. a landslide hazard map for the terri tory of zagreb c it y should also become a compo­ nent of the physical plan or zagreb city, by replacing the existing map of lithologica l classification and the slope stability categori sa tion of the mt. med ved niea hill s id es. on the basis of a landslide hazard map, the legislation restric ti ng development in the areas most susceptible to landslides could be enacted. en largement or the lands lide hazard map to the i: 10 ,000 scale could a lso serve as the bas is for con ­ struction of the physica l devclopmen t master plan of zagreb city. overlaying of the hazard map with thc map wh ich displays clements a t ri sk could indicate the level of risk. in the areas where risk is low, landslide hazard analysis will su ffi cc. 201 fig. 5 aerial photograph of kostanjck land slide ar­ ea lakcn in 1985 with inscribed landslide bou­ ndary (stan i<: & no­ nvetller ,1996). 3) at the large scale (> i: 5,000) the information of lands lidc ri sk is required. to achieve the expected deg­ ree of prec ision it is necessary to undertake comple­ mentary invest igation , fo llowed by geotechnical char­ acterisation of slope movement s, and thu s the risk assessment. the applicati on of ri sk maps li es in thc construction or urban plans and of the detailed physical deve lopment plans for the areas characterised by high risks. an example o f the area where the lands lide ri sk assessment could be undert aken is the large kostanjek lands lide on the western o ut skirts of zagreb, on the southern slopes of the m1. medvednica (fig, 5), the first movement of thi s active landslide occurred in 1963. it is est imated that a sl iding mass of some 32x 10(, 111 3 is involved, with a maximum depth of 90 m. the d isp laeemell1s on the su rface are 3-6 iii (stanic & nonveiller, 1996), the necessity for landslide ri sk assessment is conditioned by the presence of numerous houses in the area, as well as by the high level of explo­ ration including continuou s ground-displacement mea­ surements. 202 6. conclusions predictive models of landslide hazard and risk assessment constitute a major research field which may well take advantage of the potential of new technologi­ cal advancements gis-driven data acquisition, mani­ pulation and analysis. consequently, the development of the methods of prod ucing landslide hazard and risk maps is still in progress, and no uniform approach is as yet accepted. by evaluation of the methodological approaches to landslide hazard zonation practices, the stati sti cal ana­ lysis or geological-morphological causal factors is sug­ gested, aimed at the prediction of the spatial probability of landslides (i.c. where j~lilurcs are most likely to oc­ cur). this method allows production of lands lide hazard maps at the scale of 1 :25,000 at an acceptable cost. due to the variety of geological situations, the dive­ rsity of materials, the complexity of acting mechanisms and the variability of controll ing parameters, the indica­ tion of the tempora l probability of landslid ing (i.e. when failures are likely to occur) can only bc obtained by risk analysis at the detailed scale (> i : 5.000). hence, of crucial importance for risk analysis is v aunat's et al. (1994) geotechnical characterisation of slope move­ ments. to bc of value, in term s of the eval uation and presentation of landslide mi tigation alternatives, risk analysis shou ld encompass risk identification, estima­ tion, aversion and acceptance, as proposed by ander­ son et al. (1996). the priority areas for the construction of risk maps arc to be delimitcd on the basis of the hazard maps. the areas that arc to be covered by hazard maps should be determined on the basis of data fro m a national land­ slide inventory. the development of a genera l methodology for landslide hazard and risk mapping would require defini­ tion of the conceptual models, and extraction of simpli­ fi ed ope rational models from the conceptual model s. the choice of the models should also serve as a gu ide for the development of appropriate data bases, taking into account that the availability of adequate data (both in quantity and quality) is cruc ial issue enabling the task to be accomplished. acknowledgements this paper bene fit ed from constructive rev iews by prof. dr. mihael ribic ic, prof. dr. hansj6rg oeltz· schner and prof. dr. edmund krauter. i wish to especially thank prof. dr. h. oel tzschner and col­ leagues from bayerisches geologischcs landesam t for having introduced me into the georisk landslide information system. geologia croarica 5 [/2 7. references anderson. l.r .• bowles. d.s., pack, r.t. & keaton, lr. (1996): a risk-based method for landslide mitigation.in: senneset. k. (ed.): landslidcs. proc. 7th int. symp. landslides, trond­ heim 1996 .• i. 135-140. trondheim. brabb, e.e. (1984): innovative approachcs to land­ slide hazard and risk mapping.proc. 4th int. symp. landslides. toronto 1984 .. 1,307·323. toronto. brown, w.m., iii (1992): information for disaster reduction: the national landslide information cen­ ter. us geological survey.· in: bellm, d.h. (ed.): landslides. proc. 6th int. symp. landslides. christ­ church 1992.,2.891·892, christchurch. brown. w.m .• iii. cruden. d.m. & denison. j.s. (1992): the directory of the world landslide inventory.· u.s. geological survey open-filc rcp­ ort 92-427. carrara, a .• cardinali. m. , guzzetti. f. & reichenbach. p. (1995): gis technology in mapping landsl ide hazard. in : carrara, a. & guzzetti. f. (cds): geographical information systems in assessing natural hazards. kluwer academic publishers. dordrecht. 135176. chowdhury. r.n. (1984) : recent developmcnts in landslide studies : probabilistic methods. state-o[­ the-art report session vii (a).proc. 4th int. symp. landslides. toronto 1984 .• 1.209-228, toronto. cruden. d.m. (1991): a simple definition of a land­ slide.bull. of the int. assoc. of eng. geol., 43, 2729. cruden, d.m. (1996): an inventory of lands lides in alberta. canada.in: senneset, k. (ecl.): land· slides. proc. 7th int. symp. landslides. trondhcim 1996 .• 3.1877-1882. trondhcim. cruden. d.m. & varnes, d.j. (1996): land slide types and processes. in: turner. a.k. & schu· ster, r.l. (eds): landslides: invcstigation and mitigation. national academy press, washington, 36-75. fell. r. (1994): landslide risk assessment and accept­ able risk.can. gcotcch. journal. 31, 261-272. fernandez, t .• irigaray, c. & chacon, j. (1996): inventory and analysis of landslide dctenni· nant factors in los guajares mountains, granada (southern spain).in: senneset. k. (ecl.): land­ slides. proe. 7th lnt. symp. landslides, tronclheim 1996 .• 3.1891-1896. trondheim. hammond, c.j., prellwitz. r.w. & miller, s.m. (1992): landsl ide hazard assessment using monte carlo simu lation. in: bell. d.h. (cd.): lands lides. proc. 6th int. symp. landslides, christ­ church 1992 .• 2. 959-964, christchurch. mihalic: recommendations for landslide ilazard and risk mapping in croatia hansen, a. (1987): landslide hazard analysis.in: bruns den, d. & prior, d.b. (cds.): slope in­ stability. john wiley and sons, london, 523-602. iaeg commission on landslides (1990): sug­ gested nomenclature for landslides.bull. of the int. assoc. of eng. geel., 41, 13-16. lugs wg/l (1995): a suggested method for describ­ ing the rate of movement of a landslide.bull. of the int. assoc. of eng. geol., 52, 75-78. kienholz, h. (1978): maps of gcomorfology and natural hazards of grindewald, switzerland, scale 1:10.000.arctic and alpine research, 10,2,169184. krauter, e., lippomann, r, moser, m., mol­ ler, b. & prinz, h. (1996): kinematical-geotech­ nical aspects of landslides in germany.in: sen­ neset, k. (cd.): landslides. proe. 7th int. symp. landslides ,'trondheim 1996., 1, 251-256, trond­ hcim. leone, f., aste, jp & leroi, e. (1996): vulnera­ bility assessment of elements exposed to mass­ movcmnet: working toward a better risk percep­ tion. in: senneset, k. (cd.): landslides. proe. 7th int. sym p. landslides, trondheim 1996., i, 263 -270, trondheim. leroi, e. (1996): landslide hazard risk maps at dif­ ferent scales: objectives, tools and developments.­ in: senneset, k. (ed.): landslides. proc. 7th int. symp. land slides, trondheim 1996., i, 35-52, trondheim. leroueil, s, locat, j., vaunat, j. , picarel­ li, l., lee, h. & faure, r. (1996): geotechnical characterization of slope movements.tn: senne­ set, k. (cd.): landslides. proc. 7th int. symp. landslides, trondhcim 1996., i, 53-74, trondheim. mcinnes, r.g. (1996): a review of coastal landslide management on the is le of wight, uk.in: sen­ neset, k. (ed.): landslides. proc. 7th int. symp. landslides, trondhcim 1996., 1,301-307, trond­ heim. mihalic, s. (1996): zoniranje po opasnosti od klizan­ ja hazard i rizik (lands lide hazard and risk zona­ tion).unpublished m.sc. thesis, faculty of min­ ing , geology and petroleum engineering, universi­ ty of zagreb, 70 p. mihalic, s. & stanic, b. (1995): pokreti na padi­ nama hazard i rizik (slope movements hazard and risk).in: vlahovic, i., velic, 1., & spar­ ica, m. (eds): proc. 1st croatian geological con­ gress, opatija 1995., 2, 367-372, zagreb. popescu, m.e. (1994): a suggested method for reporting landslide causes.bull. of the in!. assoc. of eng. geel., 50, 7 i -74. 203 poschinger, a.v. (1994): recording and investiga­ tion of mass movements in the bavarian alps: the georisk-projeet.proc. 7th int. iaeg congress, lisbon 1994.,3,4527-4531, lisbon. ragozin, a.l. (1994): basic principles of natural hazard risk assessment and management.proe. 7th int. iaeg congress, lisbon 1994.,3, 1277-1286, lisbon. rezig, s., favre, j.l. & leroi, e. (1996): the probabilistic evaluation of landslide risk. in: sen­ neset, k. (cd.): landslides. proc. 7th int. symp. landslides, trondheim 1996., i, 351-356, trond­ heim. rosenbaum, m.s. & popescu, m.e. (1996): using a geographical information system to record and assess landslide-related risks in romania. in: senneset, k. (cd.): landslides. proc. 7th int. symp. landslides, trondheim 1996., 1,363-370, trondheim. schuster, r.l. ( 1991): landslide hazard manage­ ment experience in the united states.slope sta­ bility engincering: developments and applications. proe. int. conf. slope stability, isle of wight 1991., 253-263, isle of wight. siddle, h.j., jones, d.b. & payne, h.r. (1991): development of a methodology for landslip poten­ tialmapping in the rhondda valley.slope stability engineering; developments and applications. proc. int. conf. slope stability, isle of wight 1991. ,253263, isle of wight. soeters, r. & van westen, c.l. (1996): slope instability: recognition, analysis and zonation.in: turner, a.k. & schuster, r.l. (eds.): land­ slides: investigation and mitigation. nat ional acad­ emy press, washington, 129-177. stanic, b. & mihalic, s. ( 1995). zoniranje po opa­ snosti ad klizanja (landsl ide hazard zoning).tn: ma v ar, r. (ed.): geotechnical engineering in cit ies. proc. 2nd conf. hdmtti , varaidin 1995., i , 467-475, varaidin. stanic, b. & nonveiller, e. (1996). the kosta­ njek landslide ill zagreb.engineering geology, 42, 269-283. statham, i., langer, m.f.b. & bouckova­ las , g. (1995): the identification and monitoring of geohazards.interplay bctwcen geotechnical engineering and engineering geology. proc. xi europ. coni'. soil mechanics & foundation engi­ neering, copenhagen 1995.,9,77-104, copenha­ gen. terllen, m.t.j., van westen, c.j. & van asci-i, t.w.j. (1995): deterministic modelling in gis­ based landslide hazard assessment.in: carrara, a. & guzzetti, f. (eds.): geographical informa204 lion systems in assessing natural hazards. kluwer academ ic publi shers, 57-77, dordreeht. un esco working party on world land­ slide inventory ( 1993): a suggested mcthod for describing thc activity of a lands lide.bull. of the int. assoc. of eng. gcol. , 47, 53-57. van westen, c.j. (1993): gissiz. application of geographic information systems to landslide haz­ ard zo nation. itc publi cation no. is, enschede, 245 p. varnes, d.j. (1984): landslide hazard zonation: a review of principles and praclicc.natural hazards, 3, unesco, pari s, 63 p. vaunat, j., leroueil, s. & faure, r.m. (1994): slope movements: a geotec hn ical perspectivc.geologia croatica 51/2 proc. 7th int. iaeg congress, lisbon 1994. , 3, 1637-1646, lisbon. wieczorek, g.f. (1996): landslide tri ggering meehani sms.in: tur ner, a.k. & schuster, r.l. (eds.): landslides: investigation and mitiga ­ tion. national academy press, washington, 76-90. wp/wli (1993): a suggested method for describing the activity of a landslide.bull. of the int. assoc. of eng. geol., 47, 53-57. yin, k.l. ([994): a computer-assisted mapping of landslide hazard evaluation. proe. 7th int. iaeg congrcss, lisbon 1994.,6,4495-4499, lisbon. manuscript received june 4, 1998. revi sed manuscript accepted november 23, 1998. bulic.indd �ab stra ct the sequence of miocene fossiliferous marls of the crnika beach, along the south west shore of pag bay, consists of an alternation of silty and clayey marls, sandstones, coaly clays, coal-bearing strata and sparse intercalations of bentonite in the older part, and of an alternation of calcitic marls and organogenic fossiliferous limestones with several coal strata in the younger part. some of the strata are highly fossiliferous and rich in various species of freshwater gastropods of the genera melanopsis, theodoxus, pyrgula, prososthenia, orygoceras and valvata with the new species v. (?costovalvata) pagana. bivalves are represented by the genera congeria, unio, pisidium. there is also, a rich ostracod assemblage, and remains of fl ora: twigs, leaves and seeds of higher and lower plants, and agglomerations of aquatic grasses and algae. fish bones and teeth, as well as the crocodile tooth, are not particularly common, but they do help to complement the image of the diversity of the biological association that lived in the ancient lake and along its shores. according to facies analysis, the miocene deposits of the island of pag, were deposited on the south-western edge of paratethys, which has been moved more westward and south-westward within croatian territory. keywords: marls, limestones, coal, bentonite, lacustrine bivalves and gastropods, crocodile tooth, plant remains, early miocene, island of pag, croatia macropalaeontology and stratigraphy of lacustrine miocene deposits at crnika beach on the island of pag (croatia) � jeronim bulić and zlata jurišić-polšak croatian natural history museum, demetrova 1, hr-10000, zagreb, croatia doi: 10.4154/gc.2009.16 geologia croaticageologia croatica 1. introduction and previous investigations miocene fossiliferous deposits of the island of pag, cropping out on crnika beach are not known in other adriatic islands or along the eastern adriatic coastline. for this reason they are important and have a special value for lacustrine palaeontology and stratigraphy as well as for regional correlation. this deposit transgressively overlies upper cretaceous limestones and eocene fl ysch. the thickness is not constant and can be very variable. in kolansko polje, drilling revealed the greatest thickness of these deposits at 142 m. however, in the crnika area, the thickness of the miocene is much greater. with the assumption that the superposition relations have not been distorted by repetition, the total thickness of outcrops and deposits in the covered parts of the profi le along the crnika coastline is 265 m (figs. 1a, 1b). apart from the outcrops that are seen immediately to the rear of the beach, the miocene deposits in the crnika area are on the whole covered with quaternary sandy and gravely clays. lithifi ed coarse grained sandstones and breccias overlie the clay, making picturesque step sections that stand out on the edges of the quaternary terrace for their individual appearance. the coal layers alongside the beach of crnika have been known since the end of the 19th century, but it is only recent palaeontological research that has revealed in these deposits rich fi nds of different kinds of molluscs, plant remains, and somewhat less often the teeth of fi sh and reptiles. geologia croatica 62/3 135–155 5 figs. 6 pls. zagreb 2009 geologia croatica 62/3geologia croatica 136 mamužić et al. (1970) and mamužić & sokač (1973) determined these deposits as being of late miocene and early pliocene age. according to kochansky-devidé & slišković (1978) the bivalve congeria antecroatica katzer, discovered in kolansko polje, implies a karpatian or badenian age. our investigation and systematic collection of fossil remains alongside crnika beach took place in 2001 and later during 2004 and 2005. at that time new outcrops of miocene deposits were found behind the sv. duh beach (fig. 1a). these very fossiliferous organogenic limestones and marls with intercalations of coal, are for the moment, the youngest part of the miocene sequence in the crnika area. 2. geological setting of crnika area crnika beach is on the island of pag, part of the archipelago of the northern adriatic (fig. 1a). the island is sixty kilometres long in a nw–se orientation, i.e. so dinaric strike, and nearly ten kilometres wide. pag bay extends in the central part of the island, a drowned valley inundated by the sea. on the ne side the bay is linked to the velebit channel. with respect to geological composition and structural settings the island of pag is a continuation of the northern dalmatian mainland (zadar hinterland). it is characterised by gentle and medium-steep folds, extending in the dinaric direction (nw–se). the wings of the folds are secondarily folded and faulted with longitudinal and lateral faults. as a rule, the anticlinal parts of the folds correspond to the elonthe discovery and collection of fossil remains of fl ora and fauna in the miocene deposits on the island of pag are closely connected with extractive and geological research into the coal beds in the kolan area. there are historical data showing that the fi rst research into the coal layers started as far back as 1757 (marković, 2002). with shorter or long er interruptions, research into coal and other mining activities in kolan lasted until 1951, when coal mining was halted, the mine was closed and abandoned. although this was coal of good quality, it was estimated that the beds were too thin to make mining in kolan economically viable. the fi rst data about the fossil fl ora and fauna in the coal bearing deposits of the island of pag were recorded by radimsky (1877a, 1877b). his collection of higher plant remains, such as taxodium distichum miocenicum, glyptostrobus europaeus, sequoia langsdorfi , pinus holothana and mirca lignitum (engelhardt, 1901), is of particular value. according to the fi ndings of the genera congeria, pisidium and planorbis (hörnes, 1898) these deposits are apportioned to the sarmatian or the congerian ‘step’. schubert & waagen (1913) described the coal layers in kolansko polje and provided the fi rst complete palaeontological description of the fossil remains of fl ora and fauna, which were also the fi rst scientifi c data on fossil remains in the coal-bearing deposits of pag island. the authors promoted the opinion that the coal-bearing strata in kolansko polje were deposited at the beginning of the late miocene, precisely in the pannonian, which was earlier voiced by radimsky (1877a, b) and by pösch & hofmann (1909). fi gu re 1a: location map of crnika beach with sampling points (1−7). bulić & jurišić-polšak: macropalaeontology and stratigraphy of lacustrine miocene deposits at crnika beach on the island of pag (croatia) geologia croatica 137 fi gu re 1 b: c ro ss -s ec tio n of th e st ud ie d de po si ts in th e se ve n ou tc ro ps . geologia croatica 62/3geologia croatica 138 gated upland ridges and highs, and the synclinal parts correspond with the narrow, shallow intermontane valleys. the anticlines are composed of upper cretaceous rudist limestones and dolomites, and palaeogene foraminiferal limestones, while the synclines are fi lled with palaeogene clastics signifi cantly covered by quaternary deposits (majcen et al., 1970; mamužić et al., 1970; sokač et al., 1974). crnika beach stretches along the sw edge of pag bay, where over a distance of ca 900 m there are outcrops of miocene marls, sandstones, clays, limestones, coals and very rare and thin strata of bentonite (fig. 1b). these deposits slightly dip to the nw, with an inclination that on most of the outcrops rang es between 7 and 15 degrees. miocene deposits are rich in fossil remains of bivalves, gastropods, some higher and lower plants, as well as other organisms that populated the one-time lake and its shore. the following are particularly frequent; the bivalves congeria antecroatica, unio sp., then gastropods: two species of the genus delminiella, a new species of the genus valvata, melanopsis sp., prososthenia sp., thedoxus sp., etc. and the remains of fl ora, for example leaves of sequoia, remains of rush, lacustrine grasses, algae and the seeds of land and water plants. in addition, rare remains of fi sh teeth and bones occur and a crocodile tooth was discovered. along with the indigenous fossil molluscs, lacustrine and land terrestrial plants there are numerous well preserved foraminiferal shells which were washed out and redeposited from the nearby marls of middle eocene fl ysch deposits. 3. lithological succession of the miocene deposits alongside crnika beach, over a distance of nearly one kilometre, seven outcrops were singled out in which the miocene deposits are clearly exposed and accessible for investigation (fig. 1a). outcrops 5, 6 and 7 in the more recent part of the profi le are continuous and constitute a unique and linked superposition sequence of deposits. the other outcrops are separated by quaternary breccias, sandstones and clays, and overgrown with thick rush bushes and high grass. in total, the crnika miocene deposits form an outcrop thickness of 265 m (fig. 1b). it is possible that, in the hidden parts of the profi le, because of tectonic shifts, the deposits are repeated several times, while giving the appearance of a normal superpositionary sequence. for these reason outcrops 1, 2, 3 and 4, which occur in the older part of the profi le, cannot with certainty be placed in a normal superpositionary relationship. as shown in the composite stratigraphic column, this can only be postulated (fig. 2). the miocene deposits in crnika area are completely composed of fi ne-grained and muddy deposits: silty and clay ey marls, coaly clays and fi ne-grained organogenic limestones. but there are differences in the lithological composition between the individual outcrops because of the proportion of siliciclastic and carbonate detritus in the deposits. the siliciclastic component decreases from the older to the young er deposits, while the proportion of carbonate components increases. organic matter is equally represented in both the older and younger parts of the profi le in the form of thinner and thicker intercalations and lenses of coal. 3.1. deposits of outcrop 1 deposits in this outcrop are composed of very calcitic, silty and fossiliferous marls of a yellowish brown colour. in the lower part of the outcrop the marls are variegated with very narrow layers and laminae of light grey fossiliferous limestones−biomicrites (figs. 1b and 2). the well preserved shells of gastropods and congerians can sporadically be found over the whole surface of the outcrop, but are particularly frequent in the lower part of it. in the base of the outcrop there is a coal layer of unknown thickness (> 50 cm), of amorphous appearance, black with glossy breaks; it is easy to split into irregular small plates in which pyrite nests can be observed. between outcrops 1 and 2 in some places along the beach, below the quaternary deposits and the shoreline gravel worn, grey-blueish, fi ne-grained, calcitic sandstones and siltstones can be observed. sandstones are composed of fi ne grained detritus, comprising predominantly angular – half-rounded grains of quartz and rare grains of plagioclase, sheets of muscovite and particles of rock – including chert and quartzite. 3.2. deposits of outcrop 2 the lower part of this sequence consists of thin strata of fi negrained dark-brown sandstones alternating with thin coaly marls and laminae of coal (figs 1b and 2). in the strata alongside the beach, white sections and fragments of gastropods appear, together with a mass of their compacted shells mixed with black carbonised twigs and stems of wetland plants. in the sandy detritus, quartz grains are most abundant, alongside which small crystals of plagioclase, muscovite, grains of quartzite, chert and micrite could be seen. the matrix is sandy and clayey. the sandstones are overlain by very fossiliferous, dark-grey silty marls with a single layer of bentonite 5−7 cm thick (fig. 3a) and light grey silty marls with concretions of limonite and red-brown and yellow nodules of limonitised marls. congeria shells are frequent in the nodules of limonitised marls (pl. iv). the central and upper parts of the outcrop are characterised by very regular alternations of thin-layered, yellow-brown, fi negrained sandstones, coaly silty marls which gra dually pass into olive-grey and dark-grey coaly marls with carbonised larger parts of trees – stumps and branches (fig. 3b). 3.3. deposits of outcrop 3 the lower part of the outcrop is composed of dark-grey silty marls with carbonised branches and stumps and coal layers (figs 1b and 2). the central and upper part of the outcrop is com posed of unstratifi ed light grey and grey-red marls (fig. 3c). bulić & jurišić-polšak: macropalaeontology and stratigraphy of lacustrine miocene deposits at crnika beach on the island of pag (croatia) geologia croatica 139 3.4. deposits of the outcrop 4 these deposits crop out mid way between outcrops 3 and 5 (figs 1b and 2). the outcrop is elevated above a spacious, low coastal zone behind the beach, covered with quaternary sands and clays. in the lower part of the outcrop, a uniform sequence of unstratifi ed yellowish brown marls with very particular yellow brown limonite nodules can be observed. in the muddy marl it is possible to fi nd scattered very fi ne black fragments and debris of organic matter, of coal and small pyrite nests. the upper part of the outcrop is characterised by the alternation of calcitic silty marls and clayey marls. these deposits are characterized by a gradual change in colour. the silty marls are somewhat lighter, most often grey-orange in colour, and the clayey marls are darker, mainly of an olive-grey colour. fi gu re 2: a composite stratigraphic column of the lower miocene beds at crnika beach on the island of pag. geologia croatica 62/3geologia croatica 140 at several places along the coast, between outcrops 4 and 5, there are smaller outcrops of silty and clayey marls, with characteristic brown-yellow limonite nodules. 3.5. deposits of outcrop 5 the lithological composition of the fi fth outcrop is similar to those of the fourth one and of the smaller outcrops in the covered part of the coastal zone, between the fourth and the fi fth outcrops (figs. 1b and 2). these are rocks with a muddy matrix composed of variable proportions of silt, micrite and clay. the matrix contains scattered dotted black organic matter debris, coal and globular agglomerations of pyrite as well as relatively well preserved shells of small gastropods and ostracods. in the central part of the outcrop there is a massive marl bed, 1.5−2 m thick, with numerous moulds and whitish congerian shells (fig. 3d). 3.6. deposits of outcrop 6 the lower part of the outcrop is composed of greyish-red calcite siltstone and sandstone with coal beds (fig. 3., e and f). they are overlain by an alternation of thin strata of yellow fi gu re 3: outcrops of miocene deposits along the beach crnika. a – detail of 2. outcrop with thin layered sandstones and coaly marls. b – carbonised stumps and nodules of limonitic marls. c – beach with marl outcrops and quaternary breccias at the top of the slope. d – thin layered siltstones and silty marls. e – coal beds and marls with fossils at cap fumić. f – coal beds in the sea at cap fumić. a b c d e f bulić & jurišić-polšak: macropalaeontology and stratigraphy of lacustrine miocene deposits at crnika beach on the island of pag (croatia) geologia croatica 141 brown calcitic fi ne-grained siltstones, and olive grey marls and clayey siltstones, grey-red in colour, with intermittent and irregular narrow intercalations of coal (figs. 1b and 2). the upper part of the outcrop is composed of very fossiliferous light coloured limestones and thin strata of laminated calcitic marls, containing two coal beds of 60 and 50 cm in thickness. the limestones are recrystallised biomicrites. they are mostly composed of fi ne particles, of shattered and fragmented limestone shells of bivalves and gastropods containing a negligible proportion of quartz with the grain size of fi ne sand and silt. 3.7. deposits of outcrop 7 this outcrop lies behind the beach, some twenty metres from the coast (figs. 1a, 1b and 2). in the major part of the outcrop, and particularly in the lower part, there are fossiliferous limestones close to those of outcrop 6. the limestones are pale yellow and white, with abundant bivalve shells and gastropods. in the upper part of the outcrop the limestones are thinner and gradually pass into grey laminated marls. the laminated coaly marls at the top of the outcrop merge into layers with coal. the coal is of amorphous appearance, black in colour, with thin intercalations of marl. at the very top of the outcrop, the coal is directly overlain by light chalky biomicrites, which very probably continue into the youngest part of the profi le, which remains uninvestigated. 4. palaeontological review foraminifera foraminifera are mainly planktonic species, seldom benthic. the shells are fairly damaged, broken, fl attened, pyritized, or deformed. this suggests multiple resedimentation, and perhaps also fairly long transport. taxa from several zones are mixed, which also suggests redeposition. the foraminiferal assemblage comprises: subbotina eocaena guembel, s. hagni gohrbandt, s. cryptomphaza glaessner, morozovella spinuloza (cushman), acarinina bullbrooki (bolli), a. spinuloinfl ata (bandy), turborotalia frontosa (subbotina), t. pomeroli (toumarkine & bolli), globigerinatheca sp. and is determined as middle eocene in age. they were probably washed out from eocene fl ysch beds, and were redeposited in lacustrine deposits together with miocene fossils. mollusca clivunellidae delminiella kochansky-devidé & slišković, 1972 the shell has preserved a much reduced part of the spiral at the tip, and the rest of the spiral is restricted to a very much expanded aperture. the lines of growth are prominent, divided by furrows, and pass into dense concentric ribs. it is differentiated from the genus clivunella by the curved or spiral apex and the more remarked, denser and deeper sculpture. because the part of the spiral has been preserved, this genus is more primitive than the genus clivunella. delminiella cf. soklici kochansky-devidé (pl. i, fig. 1) 1972 delminiella soklici kochansky-devidé & slišković, pl. iii, fi gs. 3−7, pl. iv, fi g. 9 material: samples 01, 1, 3 the shell consists of 1−2 very small, spirally curved whorls, and the last half of an infl ated coil expanded at the aperture. unfortunately the pag specimens have no preserved spiral, but in the centre of the last whorl a convexity where the spiral starts can be seen. the apex that should be close to the upper edge is not preserved. the pag specimens are mainly elliptical in shape, and in this they deviate from the type species. the spiral ribs that cover the last whorl in the pag specimens are sparser and stronger. the type specimens were found in vučipolje and mokronog in duvanjsko polje, and in the area of zenica, both in bosnia and hercegovina. delminiella cf. excentrica kochansky-devidé & slišković (pl. i, fig. 2) 1972 delminiella excentrica kochansky-devidé & slišković, pl. iv, fi gs. 1−7, 10 material: samples 01, 1, 2, 3 it has a small (approximately 1 cm), almost round shell with a fl attened upper edge and an oblique, right-bent apex a little below the upper edge. the position of the apex in this species is far outside the centre of the fl at shell, and in the type specimens the apex is bent slightly to the left. the specimen of this species from the crnika site is the fi rst occurrence in croatia. type specimens were found in the livanjsko, duvansko and roško polje in bosnia and hercegovina. planorbinae gyraulus sp. a (pl. i, figs. 5−6) material: sample 1 a relatively large specimen of gyraulus (8x6 mm), it is very deformed and damaged, but nevertheless the true shape can be discerned. on the upper edge the umbilicus is not seen, but there are probably several whorls judging from their width. the last whorl expands very much towards the aperture. growth lines are visible, as well as the marked rib in the centre of the whorl. on the lower side the whorl seems completely involute, i.e., without an umbilicus. gyraulus sp. b,?n. sp. (pl. i, figs. 7−9) material: sample 28 very tiny specimens, < 1.5mm in diameter. on the shell surface a uniform spiral rib is to be seen with a very marked single rib on the upper and one rib on the lower side (like the genus platyaphus). the shell is partially involute, concave both on the upper and lower sides (fig. 4). geologia croatica 62/3geologia croatica 142 plate i 1 delminiella cf. soklici kochansky-devidé. 4x. sample 3. 2 delminiella cf. excentrica kochansky-devidé. 4x. sample 1. 3 orygoceras sp. 20x. sample 11. 4 orygoceras sp. 30x. sample 14. 5−6 gyraulus sp. a. fig. 5 x4. fig. 6 x7. sample 1. 7−9 gyraulus sp. b, fig. 7–8 x25. fig. 9 x20. sample 28. 10−11 melanopsis sp. a. 16x. sample 9. bulić & jurišić-polšak: macropalaeontology and stratigraphy of lacustrine miocene deposits at crnika beach on the island of pag (croatia) geologia croatica 143 this specimen is similar to the species gyraulus verticillus brusina in shape and to planorbis jukici brusina, both from the markuševec locality, which has one spiral rib; but spiral ribs over the whole of the shell, as has the pag gyraulus, are not present in a single one of the species mentioned. identical forms were discovered by the authors in the miocene deposits of poljanska in slavonia, north croatian basin (ncb). hydrobidae prososthenia sp. (pl. ii, figs. 11−12) materials: samples 01, 1, 3, 8, 9, 10, 12, 14 and 22 a characteristic prososthenia with a thickened lip of the aperture, that expands to the outer side, 6−7 smooth rounded whorls, particularly in the juvenile phase, while at the sides of the last and penultimate they are straighter. these two whorls are also the highest, while the whorls of the third to the juvenile whorls grow more uniformly. they occur along the whole profi le, and are very abundant at locations 8, 9 and 10. similar forms are found in lohovo (bihać basin; bosnia and hercegovina – bh), strmen dolac, košute, brnaze and peruča (sinj basin, south croatia). ?nematurella sp. (pl. iii, figs 1−4) material: sample 28 very small gastropods, about 2−3 mm high. similar forms appear in great numbers in the central european molasse basins, in the rzehakia or oncophora deposits of the ottnangian of lower bavaria (germany), ivančica in moravia (czech republic) and so on (e.g. schlickum, 1964; čtyroký 1972). our specimens recall the species nematurella klemmi schlickum. ?pyrgula sp. a (pl. ii, figs. 5−6) material: sample 2 on narrow shells (maximum height is 8 mm not including the last whorl, and the greatest width is 2 mm), consisting of about ten whorls. decorated with a single rib immediately below the suture. no umbilicus. narrow aperture, slightly thickened, and turned downwards. in the form of the shell this pyrgula is similar to the genus micromelania. pyrgula sp. b (pl. ii, figs. 7−10) material: samples 2 (many pyrgulas with 2 strong ribs), 3 (fewer, but also with two strong ribs), 14 (pyrgula with a single wing-shaped rib – like a pagoda), 15 (pyrgula with one but not winged rib), samples 16, 17 and 19 contain little pyrgulas with 2 ribs. pag pyrgulas have strong shells, consisting of seven whorls. they have a thickened aperture. the surface of the shell is decorated with a single or two spiral ribs. comparing pag pyrgula specimens with specimens of the species pyrgula carinata from the pontian trilophos formation in greece (rust, 1997) it can be said that there is evidence of polymorphism, but there are not enough specimens for the development to be tracked. still, evolution does not progress from smooth specimens here, but starts with shells with two strong ribs on the last two whorls, then,without any noted transitional forms, an elongated form of pyrgula with a single wing-shaped rib on each whorl (recall the shape of the pagoda) is observed. at later locations there are again pyrgulas with two ribs, but these are rare, and are not such marked forms. bulimidae bithynia cf. multicostata tchernov (pl. iii, figs. 5−8) 1975 bithynia multicostata tchernov, pl. ii, fi g. 3 material: sample 28 a conical shell consists of fi ve slightly rounded whorls. the last two whorls are covered with undulating radial ribs, with 15−16 of them on the last whorl. the aperture is round ed, with a slightly thickened edge. no umbilicus can be observed. this species was defi ned in the upper pliocene deposits of the central jordan valley in israel. in pre-badenian deposits of poljanska by požega (ncb), identical specimens were found (by authors) overlying deposits with leaves. similarities and differences: our specimens are very similar to ribbed bithynias from the upper pliocene deposits of the central jordan valley in israel. the pag specimens also show a similarity with the recent species baikalia (dybovskiola) ciliata (dybowski) (see wenz 1938−1944, p. 598). in form and sculpture they are practically identical specimens but the baikal specimens have ciliae and they live at a depth of about 300−350 m, while the specimens from crnika derive from a shallow water environment and could not have had ciliae. valvatidae valvata (?costovalvata) pagana, n. sp. (pl. iii, figs. 9−10) polinski (1931/32) described the subgenus costovalvata from lake ohrid on the basis of a fi nding of the fi rst species of this subgenus valvata (costovalvata) hirsutecostata. cognate species live in lake baikal. polinski points out that there are no fossil forms with such characteristics. fi gu re 4: sem bse image of gyraulus sp. b geologia croatica 62/3geologia croatica 144 plate ii 1−4 melanopsis sp. b. 2.5x fig. 1, 5x fig. 2–4. sample 22. 5−6 pyrgula sp. a. 9x. sample 2. 7−8 pyrgula sp. b. 9x. sample 2. 9−10 pyrgula sp. b. 9x. sample 14. 11−12 prososthenia sp. 12x. sample 8. bulić & jurišić-polšak: macropalaeontology and stratigraphy of lacustrine miocene deposits at crnika beach on the island of pag (croatia) geologia croatica 145 plate iii 1−4 ?nematurella sp. 20 x. sample 28. 5−8 bithynia cf. multicostata tchernov. 6 x. sample 28. 9–10 valvata (?costovalvata) pagana, n. sp. 9 x. sample 2. 11 theodoxus sp., operculum. 4 x. sample 22. 12 theodoxus sp. a. 4 x. sample 3. 13 theodoxus sp. b. 2x. sample 30. geologia croatica 62/3geologia croatica 146 wenz (1938−1944, p. 505) described the subgenus in this way: whorls with weak spiral lines and sharp radial ribs. last whorl much enlarged, infl ated downwards, broad umbilicus. aperture is large, high rather than broad. recent, lake ohrid, 1 species. schűtt (1962) described another species of the genus valvata (costovalvata) klemmi, deriving from aetolia in greece, (lakes trigonis and lysimachia). the strong shell consists of four and a half whorls. the whorl is raised with a blunt apex. the whorls are angular. juvenile whorls are smooth, and then a combination of spiral and radial sculpture is developed. radial sculpture consists of 20 or so slightly oblique rough ribs, additionally thickened with nodules. the aperture is large, circular, and polygonal. the edge of the aperture is sharp. umbilicus is narrow and deep. recent species. the new species is named after the island of pag, where it was found on the crnika beach. this is the fi rst fossil species of the genus costovalvata. the holotype (sample 2) is specimen inv. no. 10806 department of geology and palaeontology of croatian natural history museum, zagreb. 48 specimens were found, for the most part only poorly preserved. material: samples 01, 2, 3, 5 location: crnika, island of pag age: lower miocene diagnosis: surface of the shell covered with 20 or so bent radial ribs, reinforced with nodules on the places where three rows of spiral ribs pass. description: the shell has four whorls, lying markedly gradually next to each other (shouldering). the dual sculpture is interesting: three pronounced spiral nodule sequences on spiral ribs, through which 20 or so rough radial ribs pass. the umbilicus is open, the aperture is thickened. it occurs in the oldest part of the profi le, together with the clivunellas. dimensions: height 3 mm, width 4 mm. similarities and differences: this species is extremely similar to the recent species valvata (costovalvata) klemmi schűtt from greece in the form of the shell and the radial and spiral sculpture. but there are also differences. here, the aperture is rounded and is not slightly polygonal, the aperture is thickened and not sharp. the upper spiral rib is immediately below the suture, and not distant from the suture. the whole sculpture is less regular than in v. (c.) klemmi. orygoceras sp. (pl. i, figs. 3−4) material: samples 1, 2, 3, 8, 9, 10, 11, 12, 13, 14, 16, 19, 22, 23 and 29 specimens of this genus are found at practically all points of the profi le. ribbed and smooth forms often appear together, but only the smooth are more common. thiaridae brotia (tinnyea) escheri (brongniart) material: samples 01, 3, 8 several fragments found, with characteristic sculpture. melanopsis sp. a (pl. i, figs. 10−11) material: sample 9 only shell fragments are preserved, there are no complete specimens. juvenile whorls start to curve in a single plane. the initial whorls are very rounded. the fourth whorl changes, the sides of the whorl becoming almost fl at, lateral ribs appearing, and pigmentation is visible. the shell would seem to have some ten whorls. no whole specimen, but this little melanopsis might perhaps be about 1 cm long. melanopsis sp. b (pl. ii, figs. 1−4) material: sample 22 very sharped-pointed melanopsid with elongated sipho. no specimen has been extracted from marl, so it could be said that the specimens are poorly preserved. some 7 whorls were observed. neritidae theodoxus sp. a (pl. iii, fig. 12) material: samples 01, 2, 3, 5, 6, 8, 9 and 10 the typical pattern composed of irregular white spots on the dark surface of the shell is visible. but the pattern varies to spiral dark stripes fi lled with white reticular spots on the light surface of the shell, and some of the shells have light surfaces with no markings. theodoxus sp. b (pl. iii, fig. 13) material: sample 30 the specimens are at least twice as big as the specimens at the beginning of the profi le. they cannot be removed from the rock, but it would seem that the last whorl is very much enlarged, and the pattern consists of irregular triangular thin dark spots on the light surface of the shell. dreissenidae nuttall (1990) introduced a new division of congerias on the basis of their mode of life, and stated that the genus congeria is of pontian age, and the previously miocene congerias older than pontian would be classifi ed into the genus mytilopsis. because of the century-old tradition, we have retained the old name of the genus congeria also for the older miocene species. kókay (2006) also uses the genus name congeria for the ottnangian species. bulić & jurišić-polšak: macropalaeontology and stratigraphy of lacustrine miocene deposits at crnika beach on the island of pag (croatia) geologia croatica 147 congeria neumayri andrusov (pl. iv, figs. 1, 4, 7) 1978 congeria neumayri, kochansky-devidé & slišković, p. 36, plate i, fi gs. 21−25 material: sample 01, 1 and 3 flat triangular shell of medium size (height about 1.5− 2.5 cm). on some specimens brownish stripes can be seen along the growth lines. this species is found in the lower part of the profi le. according to kochansky-devidé & slišković (1978) the species c. neumayri occurs in the ottnangian of gornja planina in medvednica, and in the novo brdo bore by voloder (ncb). congeria pilari kochansky-devidé (pl. iv, figs. 5, 8) 1978 congeria pilari, kochansky-devidé & slišković, p. 44, pl. iii, fi gs. 31−33; pl. iv, fi gs. 1−12 material: samples 15, 16 a medium large congeria (height about 3 cm), with a protuberant and sharp edge, bent in the form of an s, anterior side steep and high. this species is common in the central part of the crnika profi le. according to kochansky-devidé & slišković (1978) this species occurs in the karpatian of glinsko pokuplje (kirin, dugoselo, lovča; ncb) and in northern bosnia region. congeria antecroatica katzer (pl. iv, figs. 6, 9) 1978 congeria antecroatica, kochansky-devidé & slišković, p. 48, pl. iv, fi g. 34; pl. v, fi gs. 16−21; pl. vi, fi gs. 1−18; pl. vii, fi gs. 1−13 material: samples 21, 22, 26, 29, 30 a large congeria (up to 5 cm high), sharp-edged, with a posterior side drawn out wing-shaped. very common in the most recent deposits of the profi le. according to kochansky-devidé & slišković (1978) the typical deposits are lacustrine karpatian and badenian, and in addition to those at drvar (the type location), there are occurrences at duvno, glamoč, mostar and rotimlja in bosnia and herzegowina, and also from kolan on island of pag. unionidae unio sp. (pl. v, figs. 2, 3) material: samples 21, 29 only the cores of fairly large shells are preserved (width about 6 cm, height about 3.5 cm). a hinge with strong teeth is visible. these are present mainly in the younger parts of the profi le, together with the species anodonta splendens, pisidium sp. and congeria antecroatica. anodonta splendens goldfuss (pl. v, fig. 1) 1972 anodonta splendens, čtyroký, p. 126, pl. xxi, fi g. 4 material: sample 21 the genus anodonta is kin to the genus unio, but the shells are larger and thinner, and there are no teeth on the hinge. the shells are about 8 cm long. this species was also found by authors at jelenska near kutina in northern croatia. čtyroký (1972) states that there is well known occurrence of this species at the village of ivančica in moravia (czech republic). sphaeridae pisidium sp. (pl. v, figs. 4, 5) material: samples 1, 3, 11, 13, 14, 15, 17, 19, 21, 22 shells are rounded shape (up to 1 cm broad and about 0.7 cm high). this species was observed along the whole profi le, but it is found most often in sample 21, i.e., at the younger part of the profi le, and these specimens are bigger than elsewhere. vertebrata fam. cyprinidae (pl. vi, figs. 12−14) material: samples 1, 2, 3, 8, 11, 22, 28 some dozen teeth of this group of fi sh have been found. most specimens were found at sample 3. otoliths were found at points 3 and 22. this is a fresh to brackish water group of fi sh. some species can be as long as 2.5 m, but many species are smaller than 5 cm, as was probably the case here, judging from the size of the little teeth discovered. fam. crocodylidae material: sample 3 only one tooth was found, probably belonging to a not very large specimen of crocodile. the length is 12 mm, the width 4 mm. it is conical, with a mildly curved shape, and has a rib on each side along the whole length of the tooth. crocodiles are semi-aquatic animals, live in the fresh water of rivers and lakes, but they can also be found in the brackish waters of shallow lagoons. they are limited to the warm and wet climate of the subtropical or tropical zones. flora potamogetonaceae limnocarpus sp. (pl. vi, figs. 9−11) 1978 limnocarpus longepetiolatus, bůžek & holý, p. 164, pls. i−iii material: sample 6 recent genus ruppia (there are also three species from the miocene deposits) is a halophilous genus, connected to the geologia croatica 62/3geologia croatica 148 plate iv 1 congeria neumayri andrusov. 3x. sample 3. 2, 3 congeria sp. juv. 20x. sample 8. 4, 7 congeria neumayri andrusov. 5x. sample 3. 5, 8 congeria pilari kochansky-devidé. 2x. sample 15. 6, 9 congeria antecroatica katzer. 2x. sample 21. bulić & jurišić-polšak: macropalaeontology and stratigraphy of lacustrine miocene deposits at crnika beach on the island of pag (croatia) geologia croatica 149 plate v 1 anodonta splendens goldfuss. 1.5x. sample 21. 2 unio sp. 0.5x. sample 21. 3 unio sp. 1x. sample 21. 4, 5 pisidium sp. 7x. sample 19. geologia croatica 62/3geologia croatica 150 sea coasts and slightly salty lakes. this is a species-poor underwater community that lives at a depth of 1 m. today this grass is grazed by wild ducks, and in one 5000 seeds were found, and so it is called ‘widgeongrass’, or duck grass. it is similar with fossil representatives kin to ruppia like the extinct genus limnocarpus (eocene to the upper miocene between the atlantic and lake baikal), which in addition to marine deposits is also found in fresh water, and thus makes up an ecological and taxonomic link with the limnetic genus potamogeton. limnocarpus lived in brackish lagoons and stagnant water, but always close to the sea. our specimens are reminiscent of limnocarpus cf. longepetiolatus (engelhardt) which occurs from the upper ottnangian to the karpatian of the cheb and sokolov basin in the czech republic (according to bůžek & holý, 1981). this is the fi rst discovery of ruppiaceae seeds in croatia. unger (1841−1847) described blades of the grass in the sarmatian deposits of radoboj, but seeds were not found there. capriofoliaceae ?sambucus pulchela c. & e.m. reid (pl. vi, figs. 3, 4) material: sample 18 1986 sambucus pulchela, knobloch, p. 32, pl. i, fi g. 2 knobloch (1986) mentioned an occurrence of this seed in the lower miocene of moravia (czech republic), slovakia and austria, always connected with a swampy environment, or alongside deposits of brown coal. our seed is a little narrower in form than that from moravia. ?hydrocharitaceae ?stratiotes sp. (pl. vi, figs. 1, 2) material: sample 19 taxodiaceae at the crnika profi le, fossilised twigs of these stemmed plants are close to coal deposits. at points 8 to 10 there were semicarbonised stems at the primary site, and since these deposits were discovered alongside the present coastline, sometimes larger pieces of carbonised stems are discovered in the sea. species of taxodiaceae are widespread in the tertiary of europe, and n. america too. they grew in coastal, wetland forests, particularly on the shores of stagnant waters. sediments of brown coal from this period were derived mainly from stems of taxodiaceae. this in particular relates to the genus sequoia and the species glyptostrobus europaea (brongniart) unger, similar to the cypress. for example, in sands on the main tertiary coal stratum of the rhine coal basin in germany many fossil twigs and cones were observed, of these two genera, among others (kilpper, 1968). in the upper oligocene deposits of the northern edge of saxony lausitz remains of taxodiaceae have also been found (mai, 1997). remains of leaves, fruits and seeds of taxodiaceae have also been discovered in upper austria by nieder rudling, close to eferding (kovar-eder & berger, 1987). in bosnian miocene fresh water basins, it is common to fi nd twigs and leaves of these genera (engelhardt, 1901). glyptostrobus europaea (brongniart) unger (pl. vi, figs. 5, 7, 8) material: samples 3, 5, 8, 11, 20, 25, 30 1997 glyptostrobus europaea, mai, p. 15 age: oligocene to pliocene in the whole of europe. sequoia sp. (pl. vi, fig. 6) material: sample 8 1968 sequoia langsdorfi , kilpper, p. 104, pl. 33, fi gs. 24, 31 1997 sequoia abietina, mai, p. 16 palynology according to dr koraljka bakrač (personal comment), the most frequent occurrence in sporomorphs is the pollen of trees from mixed subtropical forests (quercus, momipites, engelhartioidites), the pollen of coastal trees (carya), bush es (ephedripites, myrica) evergreen trees (pinus), swamp forests (taxodium) and ferns (polypodium). the sporomorph composition is similar to that of the lower miocene deposits of medvednica (the locality of planina). 5. discussion 1. similar fauna in the lower miocene paratethys deposits of n. croatia and the lower miocene lacustrine deposits of the dinaric palaeodepressions dinaride lake system (dls), jiménez-moreno et al. (2009), together with comparable sedimentation of marly carbonate deposits, with intercalations of coal, and lenses of pyroclastic material, confi rm the proposition (anić 1951−1953, pavelić 2002) that the dinaric lakes were also part of paratethys. it is to this lake area that, in our opinion, the ‘pag lake’ also belongs. although it is placed on the edge of the mediterranean zone, the sea could not have had an essential infl uence on the sedimentation and living environment of pag lake, which is clear from the fossils observed. on the other hand, fresh water deposits with intercalations of coal layers and the fl ora and fauna from the pag lake show a great similarity with the freshwater lower miocene deposits of the ncb and of bosnia and herzegovina (engelhardt, 1901). miocene lacustrine deposits and fossils have also been found in krbavsko polje (jurišić-polšak et al., 1993); by kosinj, where marls with freshwater fossils have been bored (fritz & pavičić, 1975); by žegar in open profi les of limestone marls, and in bilišani in marly limestones where there are plant remains, congerians, unionids, and melanias (žagar-sakač & sakač, 1984). this, then, is not an isolated discovery; rather the pag miocene lake is spatially connected with the hinterland. for this reason the border of bulić & jurišić-polšak: macropalaeontology and stratigraphy of lacustrine miocene deposits at crnika beach on the island of pag (croatia) geologia croatica 151 plate vi 1, 2 stratiotes sp. – seed, 15x. sample 19. 3, 4 sambucus cf. pulchella c. & e.m.reid seed, 16x. sample 18. 5, 7, 8 glyptostrobus sp. (fig. 5. sample 8, x10; figs. 7, 8. sample 11, x16) 6 sequoia sp., 10x. sample 8. 9, 10, 11 limnocarpus cf. longepetiolatus (engelhardt), seeds. 20x. sample 6. 12, 13, 14 cyprinidae. 30x (fig. 12. sample 28; figs. 13, 14. sample 2) geologia croatica 62/3geologia croatica 152 paratethys should be expected much further south-west than the line that anić (1951−53) and pavelić (2002) set in their studies (fig. 5). 2. the migration of species from central paratethys to the east has been known for some time, as has the population of lake baikal with many endemic species that derive from the pannonian or pontian, partially fresh, or entirely fresh water, of the inland paratethys basin (hörnes, 1898, brusina, 1874; 1887, dybowski, 1875). similarly, some forms from the older dinaric lakes are repeated in today’s lakes as endemic or cognate species. for example the species bithynia cf. costata from crnika, also discovered by the authors in poljanska, has been determined in the pliocene deposits of israel, and it is cognate to recent endemic forms from lake baikal. the ribbed valvata, here determined as subgenus costovalvata, today lives in the aetolia lake in greece (schűtt, 1962) and lake ohrid in macedonia (wenz, 1938−1944). analogously, some endemic species from freshwater lakes migrated to brackish parts of the pannonian basin during the pannonian to pliocene. the genera pyrgula, fossarulus, orygoceras, prososthenia, theodoxus and so on that lived in the miocene lakes were also alive later in the brackish paratethys (brusina, 1897, 1902). the species melanopsis defensa from the pontian deposits of paratethys (jagnjedovec, podravina) has its own cognate in the younger lacustrine deposits of livno and duvno basins (jurišićpolšak & slišković, 1988). however it is also necessary to take into consideration parallelism in the development of individual forms (kochansky-dévide, 1976). 3. fresh water miocene deposits of sinjsko and petrovo polje show a difference in fl oral and faunal composition than is the case in freshwater deposits along the crnika beach on the island of pag. in sinjsko and petrovo polje, together with some ten species of melanopsids and prososthenians, fossaruluses, congerians and unionids (brusina, 1874, 1897, 1902; neumayr, 1869) the fossilized fruits of swamp tree ceratostratiotes sinjanum kerner (bůžek, 1982), so far not known from the dinaric freshwater basins, have been found. but no clivunellas, no valvata pagana, no common species of congerians, unionids, melanopsids from pag have been found there, nor the remains of the big stem med plants the taxodiaceans. we could speak here on difference in molluscs species sense, but not in generic sense. still, the issue of the interrelation of these two basins remains unsolved for now. 4. lacustrine development of the lower miocene is present in the whole of croatia and also in western bosnia and herzegovina. despite of previous/mentioned differences we are of opinion that the dinaric neogene lakes were probably occasionally linked with a watercourse network, which enabled the migration of plant and animal species from one lake to another. so we fi nd examples of the mollusc congeria neumayri from crnika also in the n. croatian locations fi gu re 5: approximate locations of the south-western shoreline of the paratethyan sea, and the south-western boundary of central paratethys. bulić & jurišić-polšak: macropalaeontology and stratigraphy of lacustrine miocene deposits at crnika beach on the island of pag (croatia) geologia croatica 153 of planina and jelenska, the species c. pilari from crnika also in glinsko pokuplje and in n. bosnia, while c. antecroatica from crnika was also found in n. bosnia (drvar) and in duvanjsko and mostarsko polje. specimens of the genera bithynia and gyraulus identical to those of pag were found by authors at poljanska in slavonia. while in northern croatia this development was ended by marine transgression that happened everywhere during badenian (ćorić et al., 2009), at the same time, in the dinaric lakes, the freshwater regime went on until the lakes were fi lled and vanished, which largely depended on the sinking of the basins, in other words on tectonic movements. the last known lake was in lika near the little town of srb, where the fauna and fl ora has shown that the deposits are of plio−pleistocene age (jurišić-polšak et al., 1997). 5. the lacustrine development of the lower miocene is characterised by a specifi c facies of marly carbonate deposits with intercalations of coal and lenses of bentonite. as well as congerians of various species (congeria neumayri, c. pilari, c. antecroatica, c. socialis, c. zoisi, c. dalmatica, c. venusta, c. boeckhi) there are also anodonta splendens, unio sp. and pisidium sp., and the gastropod genera: brotia (tinnyea) escheri, plus several species of the genera melanopsis, bithynia, theodoxus, pyrgula, gyraulus, valvata, orygoceras. there are frequent remains of fl ora and fi sh. as for vertebrates, along the crnika profi le, only a single crocodile tooth has been found. in gornja jelenska, the remains of the proboscideans prodeinotherium bavaricum and gomphotherium angustidens, as well as rhinocerotid brachypotherium brachypus (radovčić et al., 1998) have been found. at lučane in sinjsko polje (olujić, 1999), where, together with evolutionary lineages of prososthenians and melanopsids, a new species conohyus olujici has been determined (bernor et al., 2004), the proboscidean gomphotherium angustidens and the rhinocerotid aceratherium incisivum were also observed. according to this vertebrate association, these deposits should correspond to the chronozones mn4 and mn5 (rögl & steininger, 1983). using the radiometric method ar/ ar the exact age of pyroclasts from the tuffs of the sutina site at lučane has been determined as 15.7 million years (swisher − personal comment). because of the specifi c development we propose that these freshwater deposits shoud be called the illyric. illyric originated from latin term illyricum for the area on the balkan peninsula, inhabited by illyrians (group of tribes of the indoeuropean origin) in the ancient time. the name derives from greek mythology, after illyrio, the son of kadmo and harmony. 6. in the ottnangian of central europe (slovakia, upper bavaria, upper austria) the rzehakia or oncophora brackish sediments were deposited (čtyroký, 1972). the following fossils are characteristic for these deposits: siliquia, rzehakia, limnopagetia, ctyrokya, several species of nematurella while in the croatian lacustrine miocene deposits these fossils have not been found. only the specimen anodonta splendens and nematurella sp. are common with the crnika locality. 6. conclusions (1) marls with strata of coal alongside crnika beach and similar deposits with coal in kolansko polje were created through deposition in a freshwater lake. for the most part these freshwater deposits are composed of muddy sludge; mainly of marls and coaly clays with intercalations of very fi ne-grained sandstones, organogenic limestones and frequent layers of coal. in the lithological composition of the outcrops, no coarse grained clastites were observed, which might be ascribed to a lower intensity of erosion on the land areas with the gently expressed relief behind the lake, and the lower transportation power of the watercourses that drained this area. it is assumed that these outcrops of miocene deposits on pag belonged to the same sedimentation area, i.e., a single freshwater lake, which in the lower miocene occupied the major part of today’s pag bay, the crnika beach and behind it, and a good part of kolansko polje. the limestone ridge of grubišinac, which today separates crnika and kolansko polje, was elevated later, probably as a result of post-miocene tectonics. (2) the representation of plant and animal communities in various parts of the miocene sequence in crnika area is not uniform, and shows that there were sudden changes of bioecological conditions during the sedimentation of these deposits. periods of typically lacustrine sedimentation in the area are marked by a very poor biological community, with few species, and few individuals; for example, the central part of the deposits on the profi le. against this, in the oldest and youngest deposits of the profi le, an explosive development of molluscs can be seen, particularly of gastropods and bivalves, and a lush development of plant communities, which can be ascribed to the shallowing of the lake in these periods, and the spread of marsh habitats (crocodiles, seeds of limnocarpus grass and the stemmed vegetation taxodium and sequoia). (3) at crnika, examples of the clivunellidae gastropods were observed for the fi rst time in croatia. they are otherwise known from a basement of coal in the miocene lake deposits of tušnica in the southern part of livanjsko polje. after jiménez-moreno et al. (2009) clivunellid gastropods appeared at the top of ottnangian, before more than 17 ma ago. three species of dreissenids have been determined, of which, congeria neumayri occurs in the lowest part of the profi le, c. pilari in the central part of the profi le, and in the youngest deposits we fi nd c. antecroatica. these congerias were found in several lacustrine deposits of north croatia and bosnia, as well as in herzegovina. disocvery of the species congeria pilari, is particularly important, as this has previously been known from the freshwater deposits of glinsko pokuplje and north bosnia, which lie below the badenian marine deposits (kochansky-dévide & slišković, 1978). accordingly, the deposits in which these congerias are found are older than the badenian. however, congeria neugeologia croatica 62/3geologia croatica 154 mayri suggests a possible ottnangian age of the crnika deposits, as well as for the vukov dol on medvednica mt., where this species was previously found. but a karpathian age for the crnika locality is confi rmed by the results of magnetostratigraphic investigations (jiménez-moreno et al., 2009). fish teeth and a crocodile tooth were also observed at crnika, the latter being the fi rst observation in croatia. (4) although pag lake was settled at the edge of the mediterranean zone, the sea did not have any essential effect on the sedimentation and living environment. palaeontological data suggest the conclusion that pag lake belonged in a palaeogeographic sense to a unique paratethys system of freshwater lakes that during the lower miocene covered large parts of the pannonian basin and the neighbouring dinaric area to the south. (5) freshwater lacustrine deposits of the lower miocene were developed over the whole of croatia and in west bosnia and herzegovina. because of their specifi c features, we propose that these deposits be called the illyric. in northern part of croatia such lacustrine sedimentation lasted until the lower badenian when it was ended by a marine transgression (ćorić et al., 2009). in the dinaric lakes, such a fresh water regime existed for much longer, in some areas until the pleistocene (jurišić polšak et al., 1997.). acknowledgement we wish to express our gratitude to professor r.l. bernor, representative of the national geographic and the louis leakey foundation, which provided fi nancial support for the research at crnika in 2001. we also thank professor bernor, c.s. feibel and s. bee for their collaboration and useful suggestions during the fi eld work. we also thank the protection of the geological heritage section of the croatian geological society for funding that enabled research into the miocene deposits on pag in 2000; also ivan opić (geoist d.o.o. for geological research, samobor), which provided a donation to cover the costs of chemical analyses; krešimir krizmanić and associates from the geology and geochemical department, sector sii, ina, for their work in the making of preparations and petrographic analyses. we thank darinka babac, bsc, of geološki konzalting for palaeontological analysis of foraminifers. we also would like to thank our colleagues andrejka žagarsakač, jakov radovčić, sanja japundžić and tamara đerek for help in the determination of given groups of fl ora and fauna. thanks are also due to dr. koraljka bakrač for palynological determinations. many thanks to colleague mrs. katarina krizmanić for her help in preparing the manuscript. we thank senior museum technician nives borčić for taking and processing the photographs, and dr. hrvoje posilović, assistant on the faculty of natural sciences and ivo suša (croatian geological survey) for help in preparing the graphic supplements. finally, we are greatly indebted to dr. ivo velić for his help in coordinating the manuscript with the comments and suggestions of the reviewers. references anić, d. (1951–53): starost naslaga sa smeđim ugljenom u bosni, hercegovini i dalmaciji.– geol. vjesnik, 5/7, 73–110. bernor, l.r., bi, s. & radovčić, j. (2004): a contribution to the evolutionary biology of conohyus olujici n. sp. (mamalia, suidae, tetraconodontinae) from early miocene of lučane, croatia.– geodiversitas, 26/3, 509–534. brusina, s. (1874): fossile binnen-mollusken aus dalmatien, kroatien und slavonien nebst einem anhange.– deutsche vermehrte ausgabe der kroat. im rad 28 (1874) erschienenen abhandlung – aktienbuchdruckerei, agram, 138 p. brusina, s. (1897): građa za neogensku malakološku faunu dalmacije, hrvatske i slavonije uz neke vrste iz bosne, hercegovine i srbije [matériaux pour la faune malacologique néogčne de la dalmatie, de la croatie et de la slavonie avec des espčces de la bosnie, de herzégovine et de la serbie].– djela jazu, 18, 43 p. brusina, s. (1902): iconographia molluscorum fossilium in tellure tertiaria hungariae, croatiae, slavoniae, dalmatiae, bosniae, hercegovinae, serbiae et bulgariae inventorum. operis gragja pars altera. atlas. 30 pls. bůžek, č. (1982): ceratostratiotes gregor, an extinct water plant of uncertain affi nity from the european miocene.– věstnik ústředniho ústavu geologického, 57, 5. bůžek, č. & holý, f. (1981): fruits of halophilous water plants (limnocarpus c. reid, potamogetonaceae dumortier) from the cypris formation of the cheb and sokolov basins. paleontologie, sbornik geol. ved, 24, 163–175. čtyroký, p. (1972): die molluskenfauna der rzehakia – (oncophora) – schichten mährens.– ann. naturhistor. mus. wien, 76, 41–141. ćorić, s., pavelić, d., rögl, f., mandic, o., vrabac, s., avanić, r. & vranjković, a. (2009): revised middle miocene datum for initial marine fl ooding of north croatian basins (pannonian basin system, central paratethys).– geol. croat., 62/1, 31–43. dybowski, w. (1875): die gasteropoden-fauna des baikal-sees.– impr. de ľ académie impériale des sciences st. pétersbourg, 73 p. engelhardt, h. (1901): prilog poznavanju tercijarne fl ore najšire okoline donje tuzle u bosni.– glasnik zemaljskog muzeja u bosni i hercegovini, 13/4, 473–525. fritz, f. & pavičić, a. (1975): tektonski odnosi u području krednih i jelar naslaga (tercijar) kod kosinja u lici.– geol. vjesnik, 28, 35–42. hörnes, r. (1898): sarmatische conchilien aus dem oedenburger comität. iii. die relictennatur der fauna des baikalsees.– jahrb. geol. reichsanst., 47/1, 89–94. jiménez-moreno, g., leeuw de, a., mandic, o., harzhauser, m., pavelić, d., krijgsman, w. & vranjković, a. (2009): intergrated stratigraphy of the early miocene lacustrine deposits of pag island (sw croatia): palaeovegetation and environmental changes in the dinaride lake system. palaeog. palaeoclim. palaeoecol., 280, 193−206. jurišić-polšak, z. & slišković, t. (1988): slatkovodni gastropodi neogenskih naslaga jugozapadne bosne.– zemaljski muzej bosne i hercegovine. zbornik referata naučnog skupa “minerali, stijene, izumrli i živi svijet bih”, sarajevo, 167–174. jurišić-polšak, z., krizmanić, k. & hajek–tadesse, v. (1993): freshwater miocene of krbavsko polje in lika (croatia).– geol. croat., 46/2, 213–228. jurišić-polšak, z., sakač, k. & poje, m. (1997): new pliopleistocene gastropods from lika, croatia.– natura croatica 6/1, 91–111. bulić & jurišić-polšak: macropalaeontology and stratigraphy of lacustrine miocene deposits at crnika beach on the island of pag (croatia) geologia croatica 155 kilpper, k. (1968): koniferen aus den tertiären deckschichten des niederrheinischen hauptfl ötzes, 3. taxodiaceae und cupressaceae.– palaeontographica b, 124/4–6, 102–111. knobloch, e. (1986): die untermiozäne flora aus der bohrung malešovice hv–102 (sűdlich von brno).– věstnik ústředniho ústavu geologického, 61, 29–36. kochansky-devidé, v. (1976): o slatkovodnim mekušcima srednjeg miocena hrvatske, bosne i hercegovine [über die süsswassermollusken des mittleren miozäns von kroatien, bosnien und herzegowina].– 8. jugosl. geol. kongres, 2, 125–130. kochansky-devidé, v. & slišković, t. (1972): revizija roda clivunella katzer, 1918. i delminiella n. gen. (gastropoda).– geološki glasnik, 16, 47–64. kochansky-devidé, v. & slišković t. (1978): miocenske kongerije hrvatske, bosne i hercegovine.– palaeont. jugosl. 19, 98 p. kókay, j. (2006): nonmarine mollusc fauna from the lower and middle miocene, bakony mts., w. hungary.– geologia hungarica, series palaeontologica, 56, 196 p. kovar-eder, j. & berger, j.p. (1987): die oberoligozäne flora von unter–rudling bei eferding in oberösterreich.– ann. naturhist. mus. wien, 89 a, 57−93. mai, d.h. (1997): die oberoligozänen floren am nordrand der sächischen lausitz.– palaeontographica b, 244, 124 p. majcen, ž., korolija, b., sokač, b. & nikler, l. (1970): osnovna geološka karta sfrj 1:100000 list zadar l 33–139 [basic geological map of sfry 1:10000 zadar sheet − in croatian].– institut za geološka istraživanja zagreb, savezni geološki zavod beograd. mamužić, p., sokač, b. & velić, i. (1970): osnovna geološka karta sfrj 1:100000, list silba l 33–126 [basic geological map of sfry 1:100000, silba sheet – in croatian] – institut za geo loš ka istraživanja zagreb, savezni geološki zavod, beograd. mamužić, p. & sokač, b. (1973) osnovna geološka karta sfrj 1:100000. tumač za listove molat l 33−138 i silba l 33−126 [basic geological map of sfry, 1:100000 geology of the molat and silba sheets − in croatian].− institut za geološka istraživanja zagreb, savezni geološki zavod beograd, 45 p. marković, s. (2002): hrvatske mineralne sirovine.– institut za geološka istraživanja, zavod za geologiju, zagreb, xvi+1–544. neumayr, m. (1869): beiträge zur kenntniss fossiler binnenfaunen.– jahrb. geol. r.a., 19/3, 355–382. nuttall, c.p. (1990): review of the caenozoic heterodont bivalve superfamily dreissenacea.– palaeontology, 33/3, 707–737. olujić, j. (1999): o razvojnim nizovima nekoliko melanopsida i prozostenida iz sarmatskih naslaga okolice sinja (dalmacija, hrvatska) [űber die ahnenreihen einiger melanopsiden und prosostheniden aus melanopsis lanzae – schichten der sinjaner neogenformation aus der sarmatischen stufe].– in: olujić, j. (ed.): o razvojnim nizovima nekoliko melanopsida i prozostenida iz sarmatskih naslaga okolice sinja (dalmacija, hrvatska) prepared by zlata jurišić– polšak, hrvatski prirodoslovni muzej, zagreb-sinj, 7–88. pavelić, d. (2002): the south-western boundary of central paratethys.– geol. croat., 55/1, 83–92. polinski, v. (1931/1932): die reliktäre gastropodenfauna des ochrida-sees.– zool. jahrbücher, 62/v.–vi., 611–666. pösch, a. & hofmann, a. (1909): gutachten über den kohlenbergbau von collane auf der insel pago.– montanzeitung, 16, 272–274. radovčić, j., majić, d. & jurišić–polšak, z. (1998): miocenski praslonovi i nosorozi iz moslavačkog gorja.– zbornik moslavine iv, 5–11. radimsky, o. (1877a): das lignitvorkommen auf der insel pago.– verh. geol. r.a., h 6, 95–9, wien. radimsky, o. (1877b): über den geologischen bau der insel pago.– verh. geol. r.a., 11, 181–183. rögl, f. & steininger, f. (1983): vom zerfall der tethys zu mediterran und paratethys. die neogene palaeogeographie und palinspastik des zirkum–mediterranen raumes.– ann. naturhist. mus. wien, 85, 135–163. rust, j. (1997): evolution, systematik, paläoökologie und stratigraphischen nutzen neogener süss – und brackwasser – gastropoden im nord – ägäis – raum.– palaeontographica a, 243, 37–180. schlickum, w. r. (1964): die molluskenfauna der süßbrackwassermolasse niederbayerns.– archiv für molluskenkunde, 93, 1–68. schubert, r. & waagen, l. (1913): erläuterungen zur geologischen karte der im reichsrate vertretenen königreiche und länder der österreichisch–ungarischen monarchie.sw gruppe nr. 115. pago (zone 28, col. xii der spezialkarte der österr.– ungar. monarchie im massst.1:75000) – geol. reichsanst., 32 p. schűtt, h. (1962): neue süsswasser–prosobranchier griechenlands.– arch–moll., 91, 156–166. sokač, b., nikler, l., velić, i. & mamužić, p. (1974): osnovna geološka karta sfrj, list gospić 1:100 000, l 33–127 [basic geological map of sfry, 1:100000, gospić sheet − in croatian]. – institut za geološka istraživanja zagreb, 1963–1967., savezni geološki zavod beograd. tchernov, e. (1975): the early pleistocene molluscs of ‘ erq el ahmar. the israel acad. of sc. and hum. jerusalem, 36 p. unger, f. (1841–1847): chloris protogaea. beiträge zur flora der vorwelt. – w. engelmann, leipzig, 150 p. wenz, w. (1938–1944): gastropoda. 6/1: allgemeiner teil und prosobranchia. gebruder borntraeger. berlin–zehlendorf, 1639. žagar-sakač, a. & sakač, k. (1984): nalazišta unionacejske faune neogenskih (miocenskih) naslaga dalmacije (južna hrvatska) (fundstellen der unionazeen–fauna der neogenen (miozänen) ablagerungen dalmatiens, südkroatien, jugoslawien).– rad jugosl. akad. znan. umjetn., 411, 209–230. manuscript received july 09, 2008 revised manuscript accepted september 25, 2009 available online october 30, 2009 geol. croat. 50/2 127 135 zag reb 1997 bibliography of professor milan herak bibliografija profesora milana heraka i) herak, m. ( 1943): zur kennlni s lriadiseher kalksehwiimme (sycones) .n. jb. min. geol palaeont, (abh.), (b), 88, 107135, sluttgart 2) herak , m. (1944): sto je paleobiologija?priro­ da, 34n10, 11 2116, zagreb. 3) herak , m. (1944): lz povijesl i zemlje i zivola.­ znanje i radost hrv. izd. bibliogr. zavod, 3, 160170, zagreb. 4) herak, m. ( 1944): otkrice krapinskog pracov­ jeka.znanje i radost hrv. izd. bibliogr. zavod, 3, 174-177, zagreb. 5) herak, m. (1944): triaske vapnene spu zve iz s kupinc "sycones" (triadisc he kalkschwammc aus de r gruppe "sycones") .vjes nik hrv. drz. geol zavoda, 2/3, 4 1-70, zagreb. 6) herak, m. (1945): kora zemljina pov ijesniea zivota.hrv. prir. drustvo, 5, 40 p. , zagreb. 7) herak, m. (1947): zemljina kora i zivol na njoj izv rgnut i su ncprcstanim promjenama.zadruzni kalendar, 17,257-262, zagreb. 8) herak, m. ( 1947): prilog slraligrafskom rascla­ njivanju mezozojskih nas laga jugozapadnog dije la zumberacke gore.geol vjesnik, 3-5, zagreb. 9) herak, m. (1947): slarost i sistematske wa­ caj ke spilj skog medvjeda hrvatske (geo logical age and taxonomical characters of cave-bear of croatia).geol vjesnik, 12-47, zagreb. 10) herak, m. (1948): la erosta terres tre doeumen­ taria dell'c voluzione de lla v ita.cultura unione ital ,9, 1-38, zagreb. ii) herak, m. ( 1950): ladinicke dasye ladaeeae jugoslavijc i njihova stratigrafsko znacenjc.rad jugosl akad. znan. i umjeln., 280/3, 115-142, zagreb. 12) herak , m. (195 1): ladinie dasyeladaeeae of yugos lav ia and their s tratigraphical significance.­ dull. intern . acad. yougoslav. sci. ct beaux-arts, 3, 51-56, zagreb. 13) tajder, m. & herak, m. (1951 ): petrografija i geologija.skolska knjiga, zagreb, vill+23 i p. 14) herak, m. (1952): znacenje algc sphaeroeodi­ lim bornc manni rothpletz za interpre tac iju gornjeg trijasa u podrucju zagorskc mreznice.rad jugosl akad. znan. i umjcln. , 289/4, 187195, zagreb. 15) herak , m. (1952): die bedeulung der alge sphaerocodium borne manni rothple tz fur di e inte rpretation der oberlrias im gebiet von zagors­ ka mreznica.bull. intern . acad. yougos l. sci. et beaux-arts, 7, 85-88, zagreb. 16) herak, m. (1953): paleobotan ika za geologe i biologe.skolska knjiga, zagreb, vil+ 160 p. 17) herak, m. (1954): izvjeslaj 0 gcoloskim islrazi­ vanjima u samoborskoj okolini u god ini 1952.­ ljetopis jugosl akad. znan. i umjetn. , 59 (19511952),84-86, zagreb. 18) herak, m. (1954) : 0 geoloskim prilikama pod­ rucja korane uzvodno od s iunja (uber die geolo­ gischen verhaltn isse des korana gebietes von siunj in kroatien).geol vjcsnik, 5-7 (195 11953),7-24, zagreb. 19) herak, m. (1954): lzvjestaj 0 geoloskom istra­ zivanju samoborske gore u godini 195 lljetopis jugosl akad. znan. i umjetn., 59 ( 195 1-1952), 8183, zagreb. 20) herak, m. (1955): geologija i minera log ija u srednjoj skoli.skolske novine, 6/9, 2, zagreb. 21) herak, m. (1955): gcoloska islrazivanja u pod­ rucju samoborske gore.ljetopis j ugos l. akad. znan. i umjeln., 60 (1953), 279-280, zagreb. 22) herak, m. (1956): geologija samoborskog gor­ ja (geologie des samoborer gebirges).acta gco l, i (prir. islraz. , 27), jugos l akad. wan. i umjeln. , 49-73, zagreb. 23) herak , m. ( 1956): 0 mezozoiku podrllcja kor­ ane izmedu barilovica i poloja (u be r das meso­ zoikum des korana gebietes zw ische n barilovic und poloj).geol. vjesni k, 8-9 ( 19541955), 5366, zagreb. 24) herak, m. (1956): 0 nekim hidrogeo loskim problemima male kapele (on some hydrogeologi­ cal problems of the karst mountain mala kapela in lika, croalia).geol vjcsnik, 8-9 ( 19541955), 53-66, zagreb. '" 25) herak, m. (1956): stratigrafska interpretacija lrijaskih sedimenata s dasikladacejama u okolici gracaca u hrvatskoj (stratigraphische interpreta­ tion triadischer sedimente mit dasycladaceen def umgebung von graeae in kroatien).acta geol., 1 (prir. istraz., 27), jugosl. akad. znan. i umjetn., 149-154, zagreb. 26) herak, m. & malez, m. (1956): teutloporel­ la hercu1ea (stoppani) in the district of gol u­ bovee, n-w croatia.bull. sci. cons. acad. yougos!.,2/4, 106, zagreb. 27) herak, m. (1957): osnovni principi rada u na­ s im geolosko-paleonto!oskim muzejima (basic principles of work in our geological and paleonto­ logical museums).muzeji , 11-12 (1956-1957), 49-54, zagreb. 28) herak, m. (1957): znanstveno djelo dragutina gorjanovica krambergera.oeo!. vjes nik, 10 (1 956), 1-7, zagreb. 29) herak, m. (1957): geoloska osnova nekih hid­ roloskih pojava u dinarskom krsu (geologi sche g rundj agen einiger hydrologischcn erschcinun­ gen im dinarischen karst).zbornik 2. kongr. geo!. jugos!., sarajevo, 523-539. 30) herak, m. (1957): geoloska podloga krskog podrucja.say. savj. 0 krsu krs jugos!. , 5, 11-23, split. 31) herak, m. (1957): novi nalazi sferokodija u hrvatskoj i sloveniji (neue funde von sphae­ rocodium in kroatien und slowenien).geo!. vjesnik, zagreb, 10 (1956),31-38. 32) herak, m. (1957): some problems in the dasy­ clad genus diplopora.mieropaleotology, 3/1,4952, ncw york. 33) herak, m. (1958) : the dasyclad genus physo­ porella in the anisian of yugoslavia.j. paleont., soc. india (birbal sahni mem.), 3, 59-63, luc­ know. 34) herak, m. (1959): geologija.sumarska encik­ lop. , leksikogr. zavod fnrj, 1, 437-440, zagreb. 35) herak, m. (1959) : prilog geologiji i hidroge­ ologiji otoka hvara (zur geologie und hydroge­ ologie der insel hvar).geo!. vjesnik, 12 (1958), 135-148, zagreb. 36) herak, m. & kochansky-devide, v. (1959): jurassic calcareous algae in some new localities in the dinaric mountains.bull. sci. cons. acad. yougos!., (a), 102-104, zagreb. 37) tajder, m. & herak, m. (1959): petrografija i geologija. ii izd. , skolska knjiga, zagreb, x+280p. 38) herak, m. (1960): hrvatska geoloski i petro­ grafski sastav tla. eneiklop. jugos!., zagreb, 124129. veologlil \..-roil lh.:a .1ull. 39) herak, m. (1960): geologija struktura, dina­ mika i historija zemlje.skolska knjiga, zagreb, xi+433p. 40) herak, m. (1960): calcareous algae orthe you­ ng palaezoic and mesozoic of yugoslavia, and their applications in the stratigraphy. rep. 21. sess., norden (intern. geo!. congr.), copen­ hagen, 6, 90-97. 41) herak, m. (1960): geologija gracackog polja u lici (geologie des karst polje von gracac in der lika, kroatien).geol. vjesnik, 13 (1959), 31-56, zagreb. 42) herak, m. (1960): krcda s ofiolitima u ivan­ scici (sjeverozapadna hrvatska) (kreide mi t ophiolithen in der ivan scica, nw kroatien).­ acta geo!., 2 (prir. istraz. , 29), jugos!. nkad. znan. i umjetn. , 111-120, zagreb. 43) herak , m. & kochansky -devide, v. (1960): gymnocodiacean calcareous algae in the permian of yugoslavia (gimnokodijacejske vap­ nenacke alge u permu jugoslavij e) .geol. vjes­ nik, 13 (1959), 185-196, zagreb. 44) kochansky-devide, v. & herak , m. (1960): on the carboniferous and permian dasy­ cladaceae of yugoslavia (0 karbon skim i perm­ skim dasikladacejama lugos lavij e) .geol. vjes­ nik, 13 (1959), 65-96, zagreb. 45) herak, m., bojanic, l., sikic, d. & mag­ dalenic, a. (196 1): novi clementi tektonike u podrucju gornj eg toka rij eke kupe (neue ele­ mente der tektonik im gebiet des oberlaufs des kupa-flusses).geol. vjesnik, 14 ( 1960), 245251, zagreb. 46) herak, m. (1962): dr josip poljak in memori­ am.priroda, hrv . prir. drustvo, 49/8, 256, za­ greb. 47) herak, m. (1962): news reports. yugoslavia.­ micropaleontology, 8/2, 287-288, new york. 48) herak, m. (1962): problem geoloskih kadrova.­ referati 5. say. geo!. fnr jugos!., 112, beograd. 49) herak, m. (1962): razvoj geoloske nauke u razdoblju od 1951-1961.geol. vjesnik, 15 (1961), 11-18, zagreb. 50) herak, m. (1962): vjetar kao geoloski faktor. ­ priroda, 49/8, 230-234, zagreb. 51) herak, m. (1962): tektonska osnova hidrogeo­ loskih odnosa u izvornim podrucjima kupe i korane (s plitvickim j ezerima) (tektonische grundlage der hydrogeologischen verhtiltnisse in der quell engebieten von kupa und korana mit plitwitzer seen).referati 5. say. geo!. fnr jugo­ sl., 3, 17-25, beograd. 52) herak, m. (1962): trias de la yu gos lavie.­ geol. vjesnik, 15/1 ,301 -3 10, zagreb. lilollogr;lptly 01 i'rotc~~or l\'lllan 1 tera~ ulhhograllj;l prot.dr. ~'i liana llcraka 53) herak , m. (1963) : krs.~ sumarska enciklo p. , lugos!. icksikogr. zavocl, 2, 17-20, zagreb. 54) herak, m. (1963): news reports. yugoslavia.~ micropal eonto logy, 9/3. 3s8~359 , new york. 55) tterak, m. ( 1963): paleobotanika. ~ ii izd. , skol ~ ska knj ign. zagreb. xi+ 180p. 56) her ak, m. ( 1963): trias de yugos lav i e.~ in: le trias de la france et des reg ions limitrophes. mem. bureau rcch. geol. min .. i s, 477~4s4, paris. 57) herak , m. & bahu~, s. ( 1963): prilog s trati ~ gral"skoj analizi nas laga u poclrucj u slunj-kome­ sarac-rakovica. iirvatska (ei n bcitrag zur st rati ­ graphischcn analyse del' ablagcrungcn im gcbicl slunj -kolll csa rac-rakovica, kroatien).geol. vjcsnik, 16 ( 1962), 33~34, zagreb. sr) herak, m. & kociiansky~devldt, v. ( 1963) ; lun gpaliiozoisehe kalkalge n aus clem blikk-gebi rge, norclungarn.geol. i-lung. , 28, 5769, budapes t. 59) herak, m. ( 1965): akademik marijan salopck. ~ acta geol., 5 (prir. islfaz., 35), jugosl. akad. znan. i ullljeln. , 711, zagreb. (0) herak , m. ( 1965) : gcoloska povijcsi dinarskog krsa.~ priroda, 52/5~g, 129~ 134. zagreb. 61) herak , m. ( 1965): news reports. yugoslavia. ~ micropa leonto logy, 11 /3,380, new york. (2) herak , m. ( 1965) : pal eontologija hrvat s ke. ~ enciklop. jligos l. , 6, 417, zagreb. (3) iierak , m. ( 1965): comparative study or some triassic oasyclaclaceae in yugos lav ia (kompara­ livni studij nckih trijaskih clasiklaclaceja u lugo­ s lav ij i ).~ geol vjesnik, 18/1 (1964), 3~34, zagreb. 64) herak, m. (1965): geologisc he obersieht des dinarischcn karstes.nase jame, 7, 511, ljub­ ljana. 65) herak , m. ( 1965): naslage trijasa u okolici sv. roka u liei (triasablagerungen in der umgebung von sv. rok in der lik<l).acta geo !. , 5 (pri!". istraz., 35), jugos !. akatl. znan . i umjcln., 85100, zagreb. 66) herak , m., malcen, z . & korollla, b. ( 1965): pri log palcontoloskoj doklllllentaeij i ll1ezozoika 1i smnoborskom gorjll i si zu mberkll (be itrag zur pahiontologischcn dokulllcntation des mesozoikum im samoborer gcbirge unci clem ne zulllberak).~ geol. vjesnik, 18/2 ( 1964), 325~ 33 1. zagreb. 67) herak , m. ( 1966) : die kalkalgen in del' strati~ graphic de l' dinariden (lungpaliiozoikulll llnd mcsozoikull1 ) . ~ mitt. geol. ges., 58, 21 0~217, wiel1. 129 68) herak, m. (1966): geolosko istrazivanje zuil1~ berka.~ ljetopi s lu gos!. akad. zilan. i umjcll1 ., 71 (1964), 263~265, zagreb. 69) ilerak, m. & bolanic, l. (1966): revizij a tri~ jasa 1i podrucju rijekc korane izmedu barilovita 1 siunja (revision dcr triasablagcrungcn 1m gebiet des flusscs korana zw ischen barilovic lind slu ­ nj ).~ geol. vjesn ik, 19 ( 1965), 47~5 1 , zagreb. 70) herak, m. , bolanic, l., gusic, i. & cu~ kor, v. ( 1966): pal eo ntoloska dokull1 entae ija jure u podrucju rijcke koranc izmedju bnrilovica i slunja (palaonlolog ische dokllll1cntalion cler luraablagcrungcn im geb let des flusscs korana zwischen barilovit und slunj).geol. vjesnik . 19 ( 1965), 53~s5, zagreb. 71) tajder, m. & il era k, m. (1 966): pet rograi'ija i geologija.iii izel. , skolska knji ga, zagre b, x+400p. 72) herak, m. (1967): an is isc he dasye ladaeeen yom gosaukal11l11 (dachstei ngebiet, ocslcrreich).­ mill. geol. ges., 59/2 , 213~217, wien. 73) herak, m. ( 1967): mesozoische kal kalgen de l' insel chios ( grieehenland ).~ n. lb. geol. palae~ ont. (abh. ), 129/1 , 97~ 1 04. stullgart. 74) herak, m. (1967 ): noviji rezultati istl'a y. ivanja osnovnih slraligrai"skih jecl inica u zumberku (ne­ ti c ergebnisse de l' un tersuchungen von s trati ­ graphischen hauplc inhe ilen in zlimbcrak , 'vv kroatien) . ~ geol. vjesn ik, 21 (1967 ), i ii ~ i 16 , zagreb. 75) herak, m., sokac, b. & scavnica r, b. ( 1967): correlation or the triassic in sw lika. pakl eni ea and gorski kotar, croalia. geol. sborni k siov. akad. vied (gcol. carpathiea). 18/2, 1 89 ~202 , bratislava. 76) herak , m. & skalec, d. (1967): kalkal ge n im perm des samoborer gebirges (vapnenacke alge u permll sal11oborskog golja) .geo !. vjcsnik, 20 (\ 966), 37~39, zagreb. 77) herak , m. (1968): news reports. yugos lav ia. ~ micropaleontology, 14/2, 262~263 , new york. 78) herak, m. (\ 968): s tanje i prob lemi razvoja naucnih istraz1vanja u paleolllologiji , slrali grafij i, inzenjerskoj geologiji i hidrogeologiji. ~ sav. savj. koord. nauen. del. (s tudije i prikazi sp. 9), teh ~ nieke nallke, sel. cn, 23~24, beograd. 79) iierak, m. (1968): s kompasom j eekice m po svijelu , i. dio.zumberackc no vinc, 3/ 10, l a , zagreb. 80) herak, m. ( 1968) : s kompasom i cek icem po 5vij elu, ii. clio.zlimberacke novine, 3/12, 7, zagreb. 81) herak, m., m ikulec, s. & zugaj, m. ( 1968) : present ancl prospective water power 130 development in the karst of yugoslavia.world power coni". , sec. c2, paper 158, 1-29, moscow. 82) herak , m. ( 1969): process rcpor[ for [he in[er­ national hydrological working group on the hyd­ rology of the carbonate rocks of the mediter­ ranean basin .fao, 1-32, rome. 83) herak, m. ( 1969): sveucilis[e i drus[vena prak­ s(1 .spomenie(1 svellcilista, 1,54 1-548, zagrcb. 84) herak, m. (1969): znanslvena is[raz ivanja u rerormiranom sveucilistu. simp. ins!. za drustv. istraz. svcllc., i, 1-6, zagreb. 85) herak , m. (1969): current geologic problems of the dinarides.3. simp. dinarske asoc., i, 1-9, zagrcb. 86) herak , m. ( 1969) : s kompaso m i cekicem po svijetll, 111. dio.zumberacke novine, 4/13, 9, zagreb. 87) herak , m. ( 1969): s kompasom i ceki cem po svijetu , iv. dio.zum beracke novine, 4/l5, 6, zagreb. 88) herak , m. ( 1969): s kompasom i cekice m po svijetu, v. dio.zumberacke novine, 4/16, 9, zagreb. 89) herak, m., bahun, s. & magdalenic, a. (1969): pozitivni i negativni utjecaji na razvoj krsa u hrvatskoj (positive and negative in ouences on [he developmen[ of [he kars[ in croatia).krs, jugos!. akad. znan. i umjeln., 6,45-78, zagreb. 90) herak , m., mikulec , s. & zugaj, m. (1969): mogucnosti intenzivnijcg koriscenja vod­ nih snaga krs<l.1. kongr. 0 vodama jugos !., i, 421-425, zagreb. 91) grupa autora (1969): geologija i hid roge­ ologija sli va rijeke save, lugoslavija.regulac ija i uredenjc save, zagreb, 65 p. 92) herak, m. ( 1970): dokumen[i geoloske pros­ losti. encyclop. moderna, lugos!. akad. znan. i umjeil1., 13,67-70, zagreb. 93) herak , m. ( 1970): s kompasom i ceki cem po sv ijetu, vi. dio.zumberacke novi ne, 5/ 18, 6, zag reb . 94) herak , m. ( 1970) : nase rodno [10.encyc lop. moderna , ju gos1. akad. znan. i umjcln. , 13, 66, zagrcb. 95) herak , m., mikulec, s., stojie, p. & tri­ ckovic, t. (1970): problems relati ve [0 [he con­ st ruction of dams and reservoi rs in karst areas.10. congr. grands barrages, comm. intern. gra­ nds barrages., 10, 98s-908 , mon[real. 96) herak, m. , polsak, a., gusic, 1. & babic, lj. (1970): dynamisehe und raumliehe sedimen­ tationsbedingungen der mesozoisehen karbonatgcologi" croalic;, 50(2 geste ine im dinarisehen karstgebie l. verh. geol. bundesanst., 4, 637-643, wien. 97) herak, m. (1971): reforma organizacije pos[ ­ diplomskog studija i znanstvenih istrazivanja.in: za reformu hrv. svcllc., savez stud. i-lrvat ske, 19-2 1, zagreb. 9s) herak, m. ( 1971): tek[onska os nova hidrogeo­ loskih pojava u okolie i skrada, gorski ko[ar.lje­ [opis jugosl. akad. znan. i umjc[n., 75 ( 1969-70), 425-426, zagreb. 99) herak , m. (1971 ): tragom pradavnc proslos [i zumberackog tla. in: zumbcrak u rijec i i s lici. kui1. -prosvj. drus[vo "zumberak", 10-15, zagreb. 100) herak, m. (1971): znans[veni rad i posl ije­ diplomski studij.in: za reformu itrv. svellcilista, savez stud. hrvatske, zagreb, 22-30. 10 i) herak, m. (1971): bei [rag zur rekons[ruk[ion der orogenctischen dynamik in der dinariden kroatiens.i simp. 0 orog. fa zama ii prostoru ev­ rope, beograd-bor ( 1970),35-40, beograd. 102) herak, m. (1971): razvoj hidrogeoloski h kon­ cepe ija u dinarskom krsu (develop ment of the geolog ical theories on the dinaric karst ).zbornik radova rud.-gcol. fak. , 13,227-239, beograd. 103) herak, m. ( 197 1): neke spee ificnos[i dinar­ skog krsa (some speci fi c features of the dinaric karst).simp. 0 zastiti pri rode ii nasem krsu (zagreb, 1970), jugosl. akad. znan. i umje[n., 2534, zagreb. 104) herak, m. (1972): regional geologic approach to the investigation of ground waters in karst areas.24. intern. geo!. congr. , abstracts, 342, montreal. 105) herak, m. (1972): kars[ of yugos lavia.in: herak, m. & stringfield , v.t. (cds.): karst, important karst reg ions of the northern hemisphere. elsev ier, ams[erdam, 25-83. 106) herak , m. & str ingf ield, v.t. ( 1972): histori cal review of hydrogeologic conccpts.in: herak, m. & stringfield, v.t. (cds.): karst, important karst regions of the no rthe rn hemisphere. elsevier, amsterdam, 19-24. 107) herak, m. & stringfield, v.t. ( 1972): conelusions.in: herak , m. & stringfield, v:r. (cds.): karst , important karst region s of the northern hemisphere. elsevier, amsterdam , 5075 12. los) iierak , m. & stri ng field, v.t. (cds.) ( 1972): karst, import ant karst reg ions of the northern hcmi sphcre.elsev ier, amsterdam, xv+55ip. 109) tajder, m. & herak , m. ( 1972): pe[roiogija i geo logija. iv izd. , skol ska knjiga, zagreb, x+356p. '~ 'u''''<;o ''i ' '' j vi' ''''' ... ,,~v , '''"<1,,'' 1,;,,, ... '' ", ,,ii"i,;""'j" i"""u" ",,,,,,".,.'1,;',,,, ,, 110) grupa autora (1972): gl ossa ry and multi ­ lingual equivalent s of karst terms.unesco-fa~, paris, ll+ 721'. 111 ) iierak , m. ( 1973): preg led gcoloske grade like.zbornik hi stor. arhiva, 5 (li ka u proslosti i sad asnjosti) , 79-85, karlovac . 112) herak , m. ( 1973): susreti u krsu. spomeniea m. t. lukovicu, posebna izd. srp. akad. nauka i umetn. , 60, 23-25, bcograd. 11 3) herak, m. (1973): milan lukov ic (18 891972) .ljctopis jugosl. akad. znan. i umjctn. , 77, 239-240, zagreb. 114) herak, m. ( 1973) : geologija. struktura, dina­ mika i razvoj zemlje.11 izd. , skolska knji ga, zagreb, xli+465p. 115) herak, m. ( 1973): novija istrazivanja trijasa u iirvat skoj (ncuere un tersuchungen der t rias kroatiens).geologija, 16, 375-378, ljubljana. 116) herak, m. ( 1973): some tecton i cal problems of evaporitic area in the dinarides or croatia (neki tektonski problcmi pojasa s evaporitima u dinar­ id ima hrvatske).geol. vjesnik, 26 (1972), 29-40, zagrcb. 11 7) hera k, m. , magas , b. & sar ic, a. (197 3): hidrogcoloska , geomorfoloska i hidrotehn icka bibliogratija krsa jugoslav ije ( 16891972), vodo­ pi'. problemi krsu. biltcn poslov nc zajedn icc iwc. vodopr. probl. krsa, 4, sarajevo, 209 p. 118) l ierak, m. , mikulec, s., ston c, p. & tri­ c kovic, t. (1973): jugos lavenski naeiona lni komi l e i 1.a visokc brane. sintetick i i1.vjes taj br. 10.saopstenj a 9. kongr. lugos!. kom. za visoke brane, 335-339, ziatibor. 119) gr upa autora ( 1973): karst hydrology in eight ci rcum-medi terranean countries. a rev iew of the situation in 19691971 made by the work­ ing group on the hydrology or carbonate rocks of the mediterranean basin.first preliminary edi­ tion. , uneseo-fao, rome, v+2 ip. 120) herak, m. (1974): osv rt na dosadasnji rad i perspektive. spoll1cnica prir. illatelll. [ak. , 176177, zagreb. 121 ) herak, m. ( 1974): palaogeographie und fazies­ en! wicklung wahrend der trias in den dinariden kroatiens.sylllp. d ie stratigraph ic der alpin ­ illediterr. t rias, wi en, 1973. oestelt. akad. w iss. schrifl cnrcihe cler erdwis. komlll., 2, 101 -106, wicn. 122) her ak, m. ( 1974): principi strat igrarske klasi­ f'ik acije i terminologije (principles of strat igraphic classification and terminology).nana, 25/5, 233236, zagreb. 123) herak, m. & baf-iun, s. (cds.) ( 1974): osnova hiclrogeoloskc ka rle dinarskog krsa, 151 i: 500.000 .geo!. -palcont. zavod prir. illat em . fakuitcta, zagreb. 124) her ak, m. ( 1975): pozdravn i go vor. 2. zna­ nstv. skup sekcijc 1.a primjenu geo!. , geofiz., geo­ kem. znanstv. savjeta za nanu jugos!. akad. znan. i umjetn. , 13-15, zagreb. 125) herak, m. (1975): c.a. bu rk & c.l. drake, cds.: the geology of cont inemalmargins (recenzi­ ja). springer verlag, berlin-heidelberg-new yo­ rk, 1974.geol. vjesnik, 28, 464-472, zagreb. 126) herak, m. ( 1975): geotectoni cs and karst (geotekton ika i krs).acta geol. , 8/2 1 (pri r. istraz., 4 1), jugos!. akad. znan. i umjeln. , 387395, zagreb. 127) herak, m. (1975): some eomlllents on stra li­ graph ic classifi cation and terminology (neke pri mjedbe uz stratigrafsku interpretaciju i term i­ nologiju).geol. vjesnik, 28, 55-63 , zagreb. 128) (b . k. interview m. heraka) ( 1975): do odgo­ vora nisam dosho.n in, 1281 , 1213, beograd. 129) grupa autora (1975): krska hidrolog ija u osam zcmalja na obodu sred ozemlja (preveo m . herak).izdanja poslovnc 1.ajcdnice za izucav<jnjc vodoprivr. problema krsa, 14, sarajevo , 43p. 130) her ak, m. (1976): geoloski pris tup tipi zae iji terena za konsol idac iju.1. jugos !. simp. za kon­ sol. !la, zborn ik referata , 31-32, zagreb. 131) herak, m. (1976): kako jednoznacno interpre­ ti rati rosile u cvo luciji i strati graliji?proslava 25. oblj. djelatn. hrv. geo!. drustva, sazeci refcrala , 3, zagreb. 132) herak, m. (1976): 0 gcolo.'koj proslos ti ozalj­ skog kraja.kaj, 911 , 172-174 , zagreb. 133) herak , m. ( 1976): cilj, namjena i sadr'.aj geo­ loske karte sfr j 1: 50.000. geol. vjesni k, 29, 363-374, zagreb. 134) herak, m. (1976): h idrogeoloski aspekt dinarskog krsa. simpozij ekolosko valoriziranje primorskog krsa. jugos!. akad. znan. i umjeln., 59-62, split. 135) herak, m. (1976) : jugoslavenski prilog pozna ­ vanju hidrogeologije i geomorfologije krsa. hid­ rogcolog ija i vodno bogatslvo krsa. zborn ik jugosl. -amer. simp. , d ubrovnik ( 1975), 1-24 , sarajevo. 136) herak, m. (1976): the yugoslav contr ibution 1o the knowledge or karst hydrogeology and geo­ morpho logy . karst hydrology and water reso­ urces.proceed. u.s .yugosl. symp. , dubrov nik ( 1975), water res. publ. , 1,3-30, fort coil ins. 137) herak, m. (1976): u potrazi za sil ama zemljine evolueije.priroda, 65/3, 65 -68 , zagreb. 132 138) iierak, m, kochansky-devide, kra ­ niec, v. & sinkovec, b. (1976): zcmlja cyoluc ija , struktura, dinamika i izvor sirovina.­ jugos !. akad. znan. i umjcln. , zagreb, 259 p. 139) herak, m., magas, b, saric, a. & hab e, f. ( 1976): prilog bib liografiji krsa jugosiavijc 1666-1974 (colllribution to the bib liography of k[lrst of yugos lavia 19661974).krs jugoslav ijc, 9/3 ,8 1-149, lugos!. akad. znan. i umjetn. , zagreb. 140) herak , m., marincj<:':, s. & polsak, a. ( 1976): geologija otoka hvara (geo logy of the island of hvar).acta geol. , 9/1 (prir. istraz., 42), lugos!. akad. zilan. i lill1jcln. , 1-14, zagreb. (4 1) plenicar, m. , premru, u. & herak, m. ( 1976) : osnovna gcoloska kana j ugosjavije, list novo mesto i: 100000, l33-79.geoloski zavod , ljubljana ( 1963 1969), savezni geoloski zavod, beograd. 142) hera k, m. (1977): tecto -ge netic approach to the class ification or karst tcrrains.papers of the 3rd intern. symp. ulldergr. water traci ng (1976), abst racts, 32 1, ljubljana. 143) iier ak, m. ( 1977): tecto -ge net ic approach to the classi fication of karst terrains (tektogcnctsk i pristup klasifikaciji krskih tereela).krs jugoslavi­ je, 9/4, 227-238, i ll gos l. akad. znan. i umjetn. , zagreb. (44) ii erak, m., koc i-iansky -devide, v. & gus ic, 1. (1977): the developm ent of the dasy­ c lad algae throu gh the ages.in: flogel, e. (eel. ): fossil algae. springer verlag, berlin, 143153. 145) trum1c, a. , mikulec, s. & herak , m. (1977): water resources of the dinari c karst as a facto r o f reg iona l devel opment in yugoslavia.­ uni ted nations water con ference, e/conf. , 70{!'p 54, 115 , mar del plata. 146) herak, m. , polsak , a. & prelogovic, e. ( 1978): razvoj geologije u sr hrvatskoj od 195 11976. god. geol. vjes nik , 30/2, 611 -620, zag reb. (47) herak , m. (1979): eduard roeh ( 1901-1975).­ ljetopis jugos !. akad. znan. i umjetn. , 79 (j 975), 699, zagreb. 148) hera k, m. ( 1979): surface and subsurface mor­ phology in the molai area, peloponnesus. water resources development in the molai area, laco­ nia , g reece .fao, undp-ago: dp/gre/, 771 023 , working document, i, lv+ 17p. 149) herak, m. (1979): on the ori gin of the nappe­ units in the area gorsk i kotar ljubljansko l3ar­ je.vesnik zav. geo !. geofiz. istraz. (a), 37, 5964, beograd. u\,;v'ul:"" .... ,v,"" .... . iv/ .. iso) pantic, n., herak, m., drovenik, m. & vidovic, m. ( 1979): kadrovi i naucnoi strazi­ vac ki fad u geologiji sfrj.9. kongres geo !. jugosl. (sarajevo, 1978), zbornik radova , 2, 3744, sarajevo. 151) herak , m. (1980): 0 preduvj etima se lekcije i specijali zac ije znanslvenih radnika u gcoznanost i­ ma.zbornik s imp. znan. podmlada k u samo­ upravnolll drustvu (zagreb, 1979),37-40, zagreb. 152) herak, m. (1980): sustav navlaka izmedli vrbovskog i delnica 1i gorskom kolai'll hrvnls­ ka (the nappe-system between vrbo vsko and dclnice in gorski kotar croa tia).acta geo!. , 10/2 (prir. islraz., 44). 35-5 1, jugos l. akad. znan. i umjet n. , zagreb. 153) hera k, m. (1980): zur ergunzllng tektonischer grundl agen der wcstkroati schen ausscndi na ri ­ den.ann. naturhis tor. mus., 83, 127133, wien. 154) herak , m. & ba h un, s. (1980) : the rol e of the ca lcareous brecc ias (jelar formation) in th e tcetonic interpretat ion of the hi gh karst zone or the dinarides.geol. vjesnik , 31 ( 1979),49-59, zagreb. is5) herak, m., ja sarev1c, i. , banjad, i. , sik ic, v., vrkllan, m. , duse k, a., vill e­ vac , :t, kovacevic, s. & sv ib en , d. (1980): gcoloska i geotehnicka istrazivanja s pro­ jektnirn rjese njem tuncla kroz gorski kotar. 5. simp. jugos!. druslva za mehaniku stij ena i podzemne radovc, i, ivi, 193-2 11 ,sp lil. 156) her ak, m. (198 1): inienjerskogcoloska dje lat­ nost akadcmika luke mari ca .spomen ica pre­ mil1ulim akademicima, lugos !. akad znan. i umjet n. , 10, 34-36, zagreb. 157) herak, m. (1981): uz 45 -obljet ni eli znanstve110g i nasta vl10g facia vande kochansky-dcvid6.­ geol. vjesn ik, 34,151-153, zagreb. 158) herak, m., magdalenic, a. & bai-iun , s. (198 1): karst hydrogeology.in: 1-ialas1-kun, gj. (eel. ): po llution and water resources. colu m­ bia un iv. seminar series, 14/1 , 163178, new york. 159) herak, m. (1982): ereegovac, m.: mikropal e­ oj1lol ogija mikropalcobotanika. naucna knji ga, 323 p., 1981. (reccnzija).geol. vjesnik, 35, 286287, zagreb. 160) herak, m. (1982): regianalnogeo loska asnova cvijicevc konccpcij e krsa (reg ional-geolog ic bas is of cv iji c concept of karst).naucno cicio jovana cvijica, tallcni skupovi srp. akad. nauka i umetn., 11/2,8 1-86, beograd. 161 ) herak , m. & polsak, a. (1 982) : gcologija li i-irvatskoj 1977198 1. geol. vjes nik, 35, 229294, zagreb. lilllllo:;raplly 01 i'rolcssor mjlnll i tcr.lk . 1.slbiiogr.liij~1 proi.dr. mllana ileraka 162) herak, m. (1983): some iel eas and dilemmas concern ing the genesis and tectonics of the adri­ atic and pe ri -ad riatic arcas.in: bab ic, lj. & jelaska, v. (cds.): gu ide book , 4 th i. a.s. regional meeting (split, 1983),7-11, zagreb. 163) herak, m., scavn1car, b. , susnjar a, a., durdanovic, z., krystyn, l. & gru­ ber, b. (1983): the lower triassic of muc, pro­ posa l for a standard section of the european upper scythian.osten. akad. der wiss., schrift­ cnre ihc del' erdwiss . kommiss ionen , 5, 93-106, wien. 164) ller ak, m. (1984): 0 nekim nedorecenoslill1a u raspravama 0 znanosti u nas .preclavanja lugos l. akad. znan . i umjetn., 52, 38p., zagreb. 165) iierak, m. ( 1984): gcologija.ill izd., skol ska knjiga, zagreb, xv+429p. 166) iler ak, m. (1984): effects of karst types on stream now regimes.in: lamoreaux, ph. e., morere wilson, b. & memon , b.a. (eds.): guide to the hydrology of carbonate rocks. stud­ ies and reports in ilydrology, 41, unesco. 152156, paris. 167) hera k, m. (1984): geotekton ski okvir speleo­ geneze (gcotcctonical frame or spc leogenesis).­ zborn ik devetog speleol. kongrcsa lugoslavije (kariovac, 1984), i i 1-129, zagrcb. 168) herak, m. ( 1984): osvrt na glavnc tekto­ gcnctskc staclijc dinarida (rev iew of th e main tectogeneti c stages o/" the dinariclc s) .radovi akad. nauka i umjetn . bosne i i-iercegovine, 75, odjcljcnje tehn. nauka, 8, 8 1-88, sarajevo. 169) herak , m. & burdon , d.j. ( 1984): outlels. ­ ill: lamoreaux, ph.e., morere wils on, 13. & memon, b.a. (cds.): guide to the hydrolo­ gy of carbonate rocks. studics and reports in i-iydrology, 4 1, unesco, paris, 138-141. 170) iierak, m. ( 1985): geologija u kuituj'llom i privrcdnom razvitku iirvatske.sc ienl ia yugo­ slav ica, 11/1 -2,57-63, zagreb. 17 1) herak, m. ( 1985): 0 odnosu jadrallskih i dinar­ skih struktura (on the relation or the adriatic and dinaric structures).rasprave siov. akad. znall. in umetn., iv !'azr., 26, 401-4 14, ljubljana. 172) ill::rak, m. ( 1985): gcoloska karta fuzina i oko­ li ce (geology of the environs or ru zine).in: u povodu 200. god. skole fuzine ( 1785-1985), 2 14220, fuzinc. 173) herak, m. (1986): (uvodna rijec). vale vouk 1886-1986.spomenica preminulim akadem ici­ ma, lugos!. akad. znan. i umjetn. , 35 , 9, zagreb. 174) herak, m. ( 1986): mohorov ic icev diskontinu­ it ct 1i geoznanos tim a.prirocla, 75, 106-107, hrval. prir. drustvo, zagreb. 175) herak, m. ( 1986): geologija u za tvorcnom kru­ gu. yjesnik, panorama subolom, 11.01.1986. ,8, zagreb. 176) herak, m. (1986): a ncw concept or geotecto­ ni cs of the dinarides (nova koncepcija gcole­ ktonike dinarida). acta geo!., 16/1 (pr ir. istraz., 53), lugos !. akad. zllan. i umjetn., 1-42, zagreb. 177) herak, m. (1986): geotcktonski okvir zaravni u krsu (geotectonic frame of karst plains).simp. 0 kraskom povrsju , ins!. za raziskovanjc krasa, siov. akad. znan. in umctn. (postojna, 1985 ), acta carsologica, 14/15 ( 1985-1986), 1318, lju bljana. 178) herak , m. , pantlc, n., atanackov ic, m. , karamata, s., cvetkov ic, s., bos­ kovic, d., buser, s, ivkov ic, 13., pruhti , v., kalez ic, m. & petrovsk i, k. (1986): kadrov i i naucnoistraz ivacki rad u geologiji sfrl .ii. kong!". geologa lu gos!., i , 125-j58, tara. 179) herak, m. (1987): (uvodna rijec) dragutin gorjanov ic kramberger 18561936.spomenica prcminu lim akadcmic ima lu gos!. akad. znan. i umjetn., 42, 9-11 , zagrcb. 180) herak, m. ( 1987): relation ship between adri ­ atic and dinaric platforms .intern. symp. on the evo lu tion of the karstic cabo rnate platform , abstracts, 37, in st. eli geo !. e palcont. univ. of triesle. 18 1) herak, m. (1987): geologija.iv izd., skolska knj iga, zagrcb, xv+433p. 182) li erak, m. (1987): the correlation be twecn the relief of the mohorovicic di scont inuity and the tecton ic pallern or the dinarides (korclaeija izl11edu rcljefa mohorovic iceva disko ntinuitcla i tektonske grade dinarida).acta geo!. , 17/1-2 (prir. istraz. , 55), 511 , l ugos!. akad . znan. i umjetn. , zagreb. 183) herak, m. ( 1987): trijas dinarida na prijelazu izmcdu hercinske i alpinskc orogencze (the '1'ri­ assic of the dinaricles, the li nking pcri od of her­ cynian and alpine orogenesis).zbornik raclova posvcccn akademiku z. besicu , crnogorska akacl. nauka i umjctl1. , 33-38, titograd. 184) herak, m. ( 1988): geografija i j ugoslavenska akaclcmija.geogr. gjasnik, so, 129, zagreb. 185) i-llorak, m . (1988): st ruktura i dinamika zelll ­ ije.atlas svijcta, jugos !. icksikogr. zavod, 1218, zagreb. 186) hera k, m. (1988): 0 nascill geotektons kolll naslijcdu (on our geotectoni c hcrit age).naucnc koll1unikacije akad . nauka i umjetn. bosne i hc recgov ine (oclje ljenjc tehn. nauka), 16, 515, sarajevo. 134 187) herak, m. (1988): (o prostaj ) in memoriam: akademik josip roglic ( 1906· 1987) .· geografski glasnik , 50, 129, zagreb. 188) herak, m. ( 1988): (pozdrav) zbornik skupa ornitologija u hrvatskoj. lu gos!. akad. znan. i umjetn., razred za prir. znan., 1, zagreb. 189) hera k, m. & bukoyac, j. (1988): tektonsko okno ouralijc u zumberku (tectonic window or duralije in zumberak).geol. vjesnik, 41, 231 236, zagreb. 190) her ak, m. (1989): sjecanje na dan oprostaja od akaclcmika josipa roglica.spomenica prc­ mi nulim akademicima lugos !. akad. znan. i umj ­ etn. , 51,9· 1 i, zagreb. 19 1) hera k, m. ( 1989): uloga instituta za geoloska is trazivanja u razvoju i primjeni geoloskih zna­ nosti.· geol. vjesnik, 42, xix·xx i, zagreb. 192) ii erak, m. ( 1989): re lationship between adri · atic and dinari c carbonate plalt'orms.mcm. soc. geol. 11. ,40 (1987). 289·293, roma. 193) herak, m. ( 1990): geologija.· v izd., skolska knjiga, zagreb, xv+433p. 194) hera k, m. (1990): geotectonics, karst morpho· logy, and environ mental problems.environ. geol. water sci. , 14/3,59·60, new york. 195) hera k, m. ( 1990): jugos lavija· geoloski i pet­ rografski sas tav.enciklop. ju goslavijc , lugos!. icksi kogr. zavod, 6, 167-171 , zagreb. 196) herak, m., jami cic, d. , s im un ic , a. & i3ukovac, j. (1990): the northern boundary or the dinarides (sjcvcrna granica dinarida).acta geo l. ,20/l (prir. istraz., 60), 5-27, jugosl. akad. znan. i umjetn ., zagreb. 197) hera k, m. ( 1991 ): yanda koehanskydev idc (1915-1990).· ljetopis jugosl. akad. znan. i umj­ etn., 94, 598-600, zagreb. 198) hera k, m. (1991): mirko ma lez ( 1924· 1990).­ ljetopis lu gos !. akad. znan. i umjetn. , 94, 60l m 602, zagreb. 199) herak, m. ( 199 1): u spomen vandi kochan­ sky-dev ide. spomcni ca preminu li m akademici­ m<l lugos!. akad. znal1. i umjetll. , 60, 10-12, zagreb. 200) her ak, m. (1991): dinaridi mobilisticki osvn na genezu i strukturu (dinarides mobi lislic view of the genes is and structure).acta geo!., 2j/2 (prirodosl. istraz., 63), 35·117, !-irv. akad. znan. i umjetn. , zagreb. 20 1) herak , m. (1991 ): pre-neogene tectonic pattern of the margin of the pannonian depression.serb. acado of sci and arls, acad. conferences, 62 (dept. of nat. and malhcm. sci., 4), 914, beograd. locoiogl:l l-roatlca :>uli. 202) herak , m. (1991): brusina i jugoslavcnska aka­ dcm ija.zbornik znan. skupa, zadar (1989),910, zadar. 203) her ak, m. (1992): sjccanje na akademika mir­ ka ma leza.spoj11enica prcminulim akademicim a hrv. akad. znan. i umjetn., 66, 9-11, zagreb. 204) herak, m. (1993): geotektonika i geomorro10gija.geogr. horizonti , 39/2, 5-9, zagreb. 205) herak, m. (1993): additional considerations on the epiadrialicul11, outer dinarides.gcol. croali­ ea, 46/ 1,165168, zagreb. 206) herak, m. ( 1993): gj uro pilar ( 18461893), uz stotu obljctnicu smrti .yjesnik hrv. akad. znan. i umjet n., 1-3, 223-226, zagreb. 207) herak , m. (1994): geotektonika i gco tehnika (geo tectonics and geotcchni cs).saopccnja i. znallstvello-strucnog savjctovallja gcotch nika prome tnih gradevina , novigrad ( 1994), 27-36, zagreb. 208) herak , m. (1994): pozdravni govolzbornik znanstvenog skupa gjufo pilar 1846-1893, pos. izd. hrv. akad. znan. i umjet n. , 3, zagreb. 209) herak , m. (1994): pilarovo poimanje geod i­ namike (pilar' s co nception or geodynamics).­ zbornik znanstvenog skupa gjuro pilar 1846j893, pos. izd. hrv. akad. znan. i umjetn., 73-84. zagreb. 2 10) sakac, k. & herak , m. (1994): znan stveni rad i zivotni put gjure pilara (scient ific work and life itinerary of gjuro pilar).zbo rnik znan­ stvenog skupa gju ro pi i'l l' 18461893, pos. izd. hrv. akad. znan. i umjctn. , 5-20, zagreb. 211) herak, m. (1995) : koncepcijski doseg goologi­ je hrvat ske (conceptual scope of the geology of croatia).zborn ik radova prvog hrvatskog gco­ loskog kongrcsa (opatija), 1,25-33, zagreb. 212) herak, m. (1995 ): znanstveni sku p 0 giuri pilartl. yjcsnik hrv. akad. znan. i umjetn., 4/1-3 , 166167, zagreb. 2 13) herak, m. & tom ic, v. (1995): co ntinent al subduction tccton ics in the high karst dinarides of' western croatia. geol. croatica, 48/2, 16 1166, zagreb. 2 14) herak, m. ( 1996): geologija (i-irvalske).!-l rv. icksikon, i, 379, zagreb. 215) herak , m. (1996): geoloska grada (hlvatske). ­ i-lrv. leksi kon, j, 379, zagreb. 216) herak, m. ( 1996): gjuro pilar prvi rektor prim­ doslovac na zagrcbackom svcucil istll. hrv. slo­ yo, drustvo hrv. knjiz., zagreb, 11/57, 30 (prv i dio); it/58, 30 (drugi dio). 2 17) herak, m. & juracic, m. (1996): geolog ica l basis of cil vironment protcction in croatia.tn: 1il dllogr:lpny 0 1 i 'rolcssor iviii:m 1-icr:lk tiltlllograllj:l proi.dr. 1'111:111;\ j tc raj,.;! iialas i-kun, g.1. (cd. ): pollution and wate r resources. columbia univ. seminar series, centre for reg. st udies, pees, hung. acad o sci. , 28 (1994), 233-259. 2 18) gus ic, i. & herak , m. ( 1996): reg ionalna geologija s palcontologijol11 (sazctak) .simpozij o l"ul1dal11 clllalnim istrazivanj im a, vjesnik hrv. akad. znan. i ul11jctn. , 5/1-3, 58, zagreb. 2 19) ii erak , m. (1996): helmuth zapfc ( 191 31996).ljetop is !-trv. akad. znan. i umj etn ., 100, 330-33 1, zagreb. 220) ii jorak, m. ( 1997) : nas odnos prema znanosti. ­ rugjer, 8, 13, zagreb. 22 1) herak, m. (1997): croatia. in : moors , e.m. & fa irbrldge, r.w. (cds.): encycloped ia of european and as ian regional geology. chapman & hall, london, 155-160. 222) gus ic, i. & herak , m. ( 1997): reg ionaln a gcologija s pal contologijom u nas i u svijetu (regi onal geology and paleontology in croatia and abroad).zbornik radova simp. 0 fullciamcn­ lalnim istrazivanj ima, hrv. akacl. znan. i 1iil1jcln., 199-206, zagreb. geol. croat. 49/2 339 i zagreb 1996 ahsfract note improvement of time section quality through approaching perfect static corrections "" w0 ---.' , " ali mema and durim goxhaj proceedings the plashniku region extends into the berati tecto­ nic bell of the external albanides. due 10 the discovery of two oil fields in the vici ni ty (kucova and marinza), the area is cons idered to be attractive for petroleum explora tion. in order to improve the quality or seismic data, great efforls were made by careful processing with the present software. in the regions of morc compli­ cated geological structure, like p lashnik, additiona l pro­ ced ures were applied to improve the static corrections. as a result, th e top of the mol ish ti carbonates lhal appeared to be notched, came out in the time sec tion as a serratcd one. in this way corrections were made, and the seismic data were improved considering deeper lev­ els than the molishti. the mcthod is essentially based on the fact tha t upon processing with the gath programme (plott ing of the c.d.p. traces), thc traces that fo rm a comm on depth point for a reflected wave group should be united according to a horizontal line. however, after having applied the gath programme, we observed that the traces of the top of mo[ishti carbonates for each c.d.p. are not in a horizontal line. th is anomaly is caused by two connected fac tors fi rstly by the inadequate preci ­ sion of the static corrections applied, and second ly by inadequate realisation of dynamic corrections (n.m.o.). that's why authors suggest the second step be avoided. to make corrections in this way is simple. based on the average phase of correlation of the main hori zon (top of albseis, fi er, albania. the mo[ishti carbonates), for each c.d.p. a horizontal line is drawn on the time sect ion across the bunch of traces which form this c.d.p. each c. d.p. wi ll thus have a correspond ing line with lime to of an average correlation in the time section. this line is then used as a reference line to read-off the time-shifts j"or each trace. the data are registered in a tab le containi ng: c. d.p. numbers, stacked traces (l-48) and the cor­ rection applied to each trace. these values arc then used 10 correct the time of each trace before the stacking pro­ cedure is realised. after testing the procedure on a seismic section, an increase in the reliability oj" correlat ion of the molishti limestone was noticed, whilc the wave form under thi s horizon remained the same. in other words, an increase or reliability was achieved without affecting the quality of data in deeper levels. the conclusion can be drawn that in thi s particular case, the absencc of deeper reflec­ tions is not related to the uncertainties of the stal ic cor­ rections but rather to a very complex geological struc­ ture (plashnik overthrust), which was confirmed by the jaler drilled well pi i. use of thi s method is advocated, especial ly in regions with shallow horizons that are not very strong. the method requ ires no additional field work/expenses, becau se all the operations are done in the processing centre. ] 40 geologia cro:ll ica 49n in memo.indd 117 in memoriam academician josip tišljar (1941–2009) � doi: 104154/gc.2010.07 geologia croatica 63/1 117–125 zagreb 2010 geologia croaticageologia croatica professor josip tišljar, who was a full member of the croati an academy of sciences and arts, died suddenly on august 9, 2009. he was born in the small town of ludbreg in northern croatia on june 1, 1941. after fi nishing elementary school there, and high-school in varaždin, he enrolled to study geology at the faculty of mining, geology and petroleum engineering, university of zagreb. he graduated in 1965, fi nished his msc degree in 1973, and his phd in 1976, all in natural sciences. after his graduation, josip tišljar started to work at the civil-engineering company in petrinja, but he joined the faculty of mining, geology and petroleum engineering, after only a couple of months, and remained there until his death. josip tišljar was elected as assistant in 1968, assistant professor in 1977, associate professor in 1980, professor in 1986 and professor in permanent position in 1997. he held many different positions: head of the department of geology of the faculty of mining, geology and petroleum engineering (1980–1981), director of the institute of geology and mineral deposits of the faculty of mining, geology and petroleum engineering (1981–1983), president of the council of the faculty of mining, geology and petroleum engineering (1984–1986), dean of the common study of geology of the university of zagreb (1987–1990), head of the department of mineralogy and petrology of the faculty of mining, geology and petroleum engineering (1991– 1993). professor tišljar was also responsible for all the natural science programmes at the post-graduate school of the faculty of mining, geology and petroleum engineering. professor josip tišljar was president of the sedimentological section of the croatian geological society (1980– 1982), president of the scientifi c council for petroleum of the croatian academy of sciences and arts (1996–1999), member of the state commission for scientifi c promotion in natural sciences in the ministry of science, education and sports of the republic of croatia, as well as a president of the croatian national committee for the international geological correlation programme. the scientifi c work of professor tišljar was very impressive, because geology was his passion, not only his profession. his major focus was on sedimentary rocks, an area which at the time was relatively neglected in croatian earth sciences, although croatia is especially famous for its carbonates, being part of the classical karst area. initial support was provided by his mentor, academician vladimir majer, who gave him an opportunity to fi nish specialising in clastic and clayey sedimentary rocks with professor jiřy konta (at the institute of petrology of the charles university in geologia croatica 63/1geologia croatica 118 ences, where he was always eager to discuss the details while in the fi eld. some of the guidebooks he authored or co-authored with colleagues from the croatian geological survey were widely accepted as high-quality scientifi c papers, e.g. those from the 4th international association of sedimentologists regional meeting (split, 1983), the 2nd international symposium on the adriatic carbonate platform (zadar, 1991), the 80th italian geological congress (trieste, 2000), the 6th international congress on rudists (rovinj, 2002), the 22nd international association of sedimentologists meeting of sedimentology (opatija, 2003), or the 9th international symposium on fossil algae (zagreb, 2007). professor tišljar was a member of the organizational and scientifi c committees of seven croatian and six international geological conferences. he participated in dozens of croatian and international scientifi c conferences, where he presented more than 20 invitation lectures. professor tišljar was the principal investigator on many projects and the director of one programme funded by the croatian ministry of science, education and sports. he also participated in several international, bilateral and igcp projects focused on the study of the karst dinarides and their correlation with neighbouring areas. his very wide theoretical knowledge and impressive practical experience enabled him to introduce and continuously improve several courses on the petrology of sedimentary rocks and sedimentology in undergraduate and postgraduate studies, where he was also one of the best advisors. besides several dozens of bsc theses he was an advisor of 11 msc and 8 phd thesis, as well as a member of evaluating committees for more than 30 msc and phd exams. professor tišljar published 5 books, among which two, sedimentology of carbonates and evaporites (2001), and sedimentology of clastic and siliceous deposits (2004) published by the croatian geological survey, probably represent the most important books on croatian sedimentology, since state-of-the-art scientifi c information was accompanied by hundreds of examples from mostly his own and his colleagues extensive work throughout croatia. he also published 59 peerreviewed papers, 66 abstracts and papers in conference proceedings, 40 chapters in books (mostly fi eld-trip guide-books), and he was co-editor of another three books. however, by far the most important editorial achievement of professor josip tišljar was his long-lasting support of the leading croatian geological journal, ‘geologia croatica’, since he was a member of the editorial board of its predecessor ‘geološki vjesnik’ since 1986, and continued as a member of the ‘geologia croatica’ board from 1991 until his death. he was a very pro-active, passionate and scientifi cally brilliant associate editor, keeping eye on the quality of sedimentological papers, but also those dealing with other disciplines, since his knowledge was very wide. he is defi nitely one of the small group of dedicated people responsible for survival of the journal through some very harsh times, and helped to achieve continually higher standards, enabling it to become one of the best geological journals in the entire region. prague), as well as specialising in carbonate deposits with professor hans füchtbauer (at the institute of geology of the ruhr university in bochum). soon after this, he decided to focus especially on carbonates, and a major part of his future investigations and publications was dedicated to different aspects of the sedimentology of carbonates and evaporites. a list of more than 170 publications shows his wide scientifi c interests. at the beginning of his career he was mainly focused on the study of the ophiolitic melange in the area of central dinarides and vardar zone, mostly fi ne-grained clastic deposits and radiolarian cherts. later he studied tertiary clastic deposits, carbonates and marls of the croatian part of the pannonian basin, especially glauconitic sandstones and their association with volcanoclastic deposits. during his studies of deep wells in the pannonian basin he focused on the regional characteristics and sedimentology of marginal areas of the psunj, papuk and žumberak mts., mainly on clastic rocks with the role of source and reservoir rocks for hydrocarbons. one of the important contributions of professor tišljar was his sedimentological approach to the complex multidisciplinary study of pre-tertiary and tertiary tectonics, stratigraphy and sedimentology of bauxite deposits in the area of the karst dinarides in croatia and bosnia and herzegovina. however, most of his work was focused on the geological love of his life: shallow-marine carbonates. over decades, he studied numerous profi les in croatia from savudrija along the slovenian border to the far se, prevlaka area at the montenegro border, and from palagruža island to the northeasternmost carbonates in croatia, as a member of multidisciplinary teams. he produced dozens of reports for scientifi c projects and many companies, always including all details on the structure and texture of rocks, their facies and microfacies, environments, diagenetic processes, palaeogeographical meanings and all other aspects. he was the fi rst croatian sedimentologist to discuss in detail, stromatolites, oncolites, early-diagenetic dolomites, shallowing-upward cycles and black-pebble breccias. his careful study of these rocks made him famous not only in croatia, and he presented his knowledge at many conferences and lectures throughout europe. lately he was focused on the problem of different varieties of carbonate breccia, a very intriguing and complex topic. through the decades, he received very good cooperation from many colleagues and institutions, especially with the croatian geological survey, (he cooperated on lengthy studies of jurassic and cretaceous successions throughout the dinarides and was involved in many activities in the planning, production and review of the new lithostratigraphic map of the republic of croatia, together with many other issues) and the national oil company ina (where he was an expert for numerous croatian and international projects). he also produced consultancy work for chevron, texaco and agip. his enthusiasm to share the results of his investigations with others was especially noteworthy, and he led numerous fi eld trips on croatian and international geological conferigor vlahović, ivo velić & branko sokač: in memoriam academician josip tišljar (1941–2009) geologia croatica 119 tišljar, j. (1973): kvantitativna petrološka studija sedimenata »fl išne serije« i jurske vulkanogeno–sedimentne formacije borovičkog potoka u sjevernom krilu »velikog vareškog antiklinorija«.– geološki glasnik, 17, 133–168. majer, v. & tišljar, j. (1973): spilit i andezin–dijabaz velike trepče u pokuplju i spilit hrvatskog sela kod topuskog u baniji (hrvatska, jugoslavija).– geološki vjesnik, 26, 139–153. balen, i., tišljar, j. & majer, v. (1975): petrografske karakteristike lapora okolice podsuseda na jugozapadnim obroncima medvednice.– geološki vjesnik, 28, 167–172. füchtbauer, h. & tišljar, j. (1975): peritidal cycles in the lower cretaceous of istria (croatia, yugoslavia).– sedimentary geology, 14, 219–233. tišljar, j. (1976): ranodijagenetska i kasnodijagenetska dolomitizacija i dedolomitizacija u krednim karbonatnim sedimentima zapadne i južne istre (hrvatska, jugoslavija).– geološki vjesnik, 29, 287–321. bojanić, a., tišljar, j. & majer, v. (1978): klastični miocenski sedimenti sjeverozapadnog dijela maceljske gore (sjeverna hrvatska).– geološki vjesnik, 30/2, 445–453. tišljar, j. (1978): onkolitni i stromatolitni vapnenci u donjokrednim sedimentima istre.– geološki vjesnik, 30/2, 363–382. tišljar, j. (1978): tidal fl at, lagoonal and shallow marine carbonates in the upper jurassic and cretaceous of istria (yugoslavia).– acta geologica, ix/5, 159–194. tišljar, j. (1979): fenestralni sklop i vadozne ranodijagenetske tvorevine u litoralnim (periplimnim) vapnencima titon–berijasa okolice dubrovnika.– krš jugoslavije, 10/3, 77–86. tišljar, j. (1979): ranodijagenetske promjene pojedinih sastojaka donjokrednih vapnenaca iz različtih dijelova vanjskih dinarida.– geološki vjesnik, 32, 255–263. velić, i., tišljar, j. & sokač, b. (1979): stratigraphy and depositional environments of the lower cretaceous in the karst region of dinarides (yugoslavia).– geobios, mem. spec., 3, 245–252. blašković, i., tišljar, j. & velić, j. (1981): ritmična sedimentacija donjosarmatskih naslaga jugozapadnih obronaka psunja.– nafta, 32, 5–14. blašković, i., tišljar, j. & velić, j. (1982): litofacijesne značajke tortonskih naslaga u području okučani–pakrac–novska.– geološki vjesnik, 35, 71–86. blašković, i. & tišljar, j. (1983): prominske i jelar naslage u vinodolu (hrvatsko primorje).– geološki vjesnik, 36, 37–50. tišljar, j., velić, i. & sokač, b. (1983): flachwasserkarbonate der unterkreide im dinarischen karstgebiet entlang der adria küste.– zitteliana, 10, 201–206. aljinović, b., blašković, i. & tišljar, j. (1984): determinacija korespodentnih sekvencija na geološkim profi lima primjenom elementarne seizmičke korelacije.– nafta, 35/4, 181–190. blašković, i., tišljar, j., dragičević, i. & velić, j. (1984): razvoj sedimentacijskih okoliša miocenskih naslaga na zapadnim obroncima psunja (sjeverna hrvatska).– geološki vjesnik, 37, 11– 32. tišljar, j. (1985): strukturni tipovi i okoliši taloženja jurskih onkoidnih i ooidnih vapnenaca južnog jadrana.– krš jugoslavije, 11/3, 71–99. dragičević, i., tišljar, j., blašković, i. & benić, j. (1986): mehanizam taloženja krovinskih naslaga ležišta boksita kao odraz paleoreljefa podine (primjer boksitonosnog lokaliteta studena vrila, zapadna hercegovina).– naučne komunikacije i, odjelenje tehničkih nauka 1, anubih, 5–31. tišljar, j. (1986): postanak crnih oblutaka i ulomaka (»black pebbles«) u periplimatskim vapnencima titona zapadne istre i barema otoka mljeta.– geološki vjesnik, 39, 75–94. he was also a member of the editorial board of the slovenian scientifi c journal ‘geologija’ since 1998. for his work, josip received numerous awards, and the most important ones were two ‘josip juraj strossmayer’ awards given by the croatian academy of sciences and arts for his books (1994 and 2004), and ‘award of the city of zagreb’ (2005) for his complete work in the fi eld of sedimentology. professor josip tišljar was elected as an associate member of the croatian academy of sciences and arts, in the department of natural sciences, in 1983, and he became a full member in 2004, as one of the youngest members of the academy, being very active in many areas. josip had so many plans for the future in all fi elds, from scientifi c, where he opened some completely new areas recently, to his family, where he planned to spend more time with his beloved wife vesna, their two sons, zvonimir and mladen, and his immense joy, grandchildren, either in his home in zagreb, weekend house in ludbreg or in the alps, mountains that he truly adored. unfortunately, his sudden death on august 9, 2009 curtailed all of his and our plans, and was an incredible shock to us all. summarizing his lifelong scientifi c contribution, there is no doubt that he was among the best ever croatian geologists, not only of his generation, and the leading croatian sedimentologist. we will remember professor tišljar as a great fi eld geologist, since he was ready to raise questions over and over again, looking at every outcrop carefully, even if he was there more than a dozen times; and yes, he would always fi nd something new, transmitting his passion for scientifi c work to many younger generations. he was always ready to patiently answer all questions asked by anybody, from the fi rstyear student to his fellow academicians. however, he was never afraid to say that he did not know the answer or to accept another opinion if the evidence was stronger, making his scientifi c credibility exceptionally strong among all of us who had the privilege to know him. and we will defi nitely remember professor tišljar, our joža as we used to call him, as a great friend and a great man who loved so passionately his profession, his colleagues, his country, and his family. let him rest in peace! igor vlahović, ivo velić and branko sokač bibliography peer-reviewed papers tišljar, j. & majer, v. (1972): prinos poznavanju petrografskog sastava morenskog nanosa kod brezovice na sjevernoj strani šar planine.– geol. anali balk. poluostrva, xxxvii, 219–232. majer, v. & tišljar, j. (1973): spilitske stijene kod sela lasinja u pokuplju (hrvatska, jugoslavija).– geološki vjesnik, 25, 211– 225. geologia croatica 63/1geologia croatica 120 tišljar, j. & velić, i. (1987): oberjurassische gezeitenbarren– kalkarenitfazies westistrien (westkroatien, jugoslawien).– heidelberger geowissenschaftlich, abh., 8, 251–255. tišljar, j. & velić, i. (1987): the kimmeridgian tidal-bar calcarenite facies in western istria (western croatia, yugoslavia).– facies, 17, 277–284. velić, i. & tišljar, j. (1987): biostratigrafske i sedimentološke značajke donje krede otoka veli brijun i usporedba s odgovarajućim naslagama jugozapadne istre.– geološki vjesnik, 40, 149–168. špalj, d. & tišljar, j. (1988): glaukonitni pješčenjaci u badenskim sedimentima okolice novog marofa.– geološki vjesnik, 41, 159– 165. velić, i. & tišljar, j. (1988): litostratigrafske jedinice u dogeru i malmu zapadne istre (zapadna hrvatska, jugoslavija).– geološki vjesnik, 41, 25–49. pikija, m., šikić, k., tišljar, j. & šikić, l. (1989): biolititni i prateći karbonatni facijesi sarmata u području krašić–ozalj (središnja hrvatska).– geološki vjesnik, 42, 15–28. tišljar, j., velić, i. & sokač, b. (1989): einfl üsse von emersionen auf die flachwasser-karbonatsedimentation im malm (ober jura) des biokovo-gebirges (südkroatien, jugoslawien).– geol. palaont. mitt. innsbruck, 16/1, 199–201. velić, i., tišljar, j. sokač, b. (1989): the variability of thicknesses of the barremian, aptian and albian carbonates as a consequence of changing depositional environments and emersions in western istra (croatia, yugoslavia).– mem. soc. geol. italia, 40, 209–218. tišljar, j. (1990): postsedimentne dolomitizacijske breče u jurskim plitkomorskim karbonatnim sedimentima malog alana na južnom velebitu.– rgn zbornik, 2, 59–65. tišljar, j. & velić, i. (1991): carbonate facies and depositional environments of the jurassic and lower cretaceous of the coastal dinarides (croatia).– geološki vjesnik, 44, 215–234. dragičević, i., blašković, i., tišljar, j. & benić, i. (1992): stratigraphy of paleogene strata within the mesihovina–rakitno area (western herzegovina).– geologia croatica, 45, 25–52. tišljar, j. (1992): origin and depositional environments of the evaporite and carbonate complex (upper permian) from the coastal part of the dinarides (southern croatia and western bosnia).– geologia croatica, 45, 115–126. pikija, m., šikić, k., tišljar, j. & hrabak, n. (1993): miocene formations of the molve–kalinovac area (north croatia).– nafta, 12, 665–671. tišljar, j. (1993): sedimentary bodies and depositional models for the miocene oil-producing areas ladislavci, beničanci and obod (croatia).– nafta, 10, 531–542. tišljar, j. & velić, i. (1993): upper jurassic (malm) shallow water carbonates of the western gorski kotar: facies and depositional environments (croatia).– geologia croatica, 46/2, 263–279. tišljar, j., velić, i. & vlahović, i. (1994): facies diversity of the malmian platform carbonates in western croatia as a consequence of synsedimentary tectonics.– géologie méditerranéenne, 3–4, 173–176. velić, i., vlahović, i. & tišljar, j. (1994): late jurassic lateral and vertical facies distribution: from peritidal and inner carbonate ramps to perireefal and peritidal deposits in se gorski kotar (croatia).– géologie méditerranéenne, 3–4, 177–180. vlahović, i., tišljar, j. & velić, i. (1994): infl uence of synsedimentary tectonics and eustatic changes on deposition of the cenomanian platform carbonates in istria (western croatia).– géologie méditerranéenne, 3–4, 189–193. blašković, i., dragičević, i. & tišljar, j. (1995): morphological and geological indicators of the possible bauxite deposits in the karst region of western herzegovina.– rgn zbornik, 7, 17–27. matičec, d., vlahović, i., velić, i. & tišljar, j. (1996): eocene limestones overlying lower cretaceous deposits of western istria (croatia): did some parts of present istria form land during the cretaceous?– geologia croatica, 49/1, 117–127. tadej, n., slovenec, d. tišljar, j. & inkret, i. (1997): glauconitic materials from lower miocene macelj-sandstones of the hrvatsko zagorje, north-western croatia.– geologia croatica, 50/1, 17–25. tišljar, j., đokić, z. & ženko, t. (1997): infl uence of the sedimentary environment on the technical properties of the lower cretaceous limestones from the lakovići quarry in istria (croatia).– rgn zbornik, 9, 23–39. tišljar, j., vlahović, i., velić, i., matičec, d. & robson j. (1998): carbonate facies evolution from the late albian to middle cenomanian in southern istria (croatia): infl uence of synsedimentary tectonics and extensive organic carbonate production.– facies, 38, 137–152. ottner, f., durn, g., schwaighofer, b. & tišljar, j. (1999): clay minerals in paleosols of cretaceous age in istria, croatia.– chinese science bulletin, 44, suppl. 1, climatic change: paleopedological and soil rocks magnetic approaches, 145–151. velić, j., tišljar, j., dragičević, i. & blašković, i. (2000): shoreline cross-bedded biocalcarenites (middle miocene) in the podvrško–šnjegavić area on the slope of mt. psunj and their petroleum signifi cance (požega subdepression – eastern croatia).– geologia croatica, 53/2, 281–293. tišljar, j., vlahović, i., velić, i. & sokač, b. (2002): carbonate platform megafacies of the jurassic and cretaceous deposits of the karst dinarides.– geologia croatica, 55/2, 139–170. velić, i., tišljar, j., vlahović, i., velić, j., koch, g. & matičec, d. (2002): palaeogeographic variability and depositional environments of the upper jurassic carbonate rocks of velika kapela mt. (gorski kotar area, adriatic carbonate platform, croatia).– geologia croatica, 55/2, 121–138. vlahović, i., tišljar, j., fuček, l., prtoljan, b., velić, i. & matičec, d. (2002): the origin and importance of the dolomite–limestone breccia between the lower and upper cretaceous deposits of the adriatic carbonate platform: an example from ćićarija mt. (istria, croatia).– geologia croatica, 55/1, 45–55. vlahović, i., tišljar, j., velić, i. & matičec, d. (2002): the karst dinarides are composed of relics of a single mesozoic platform: facts and consequences.– geologia croatica, 55/2, 171– 183. tišljar, j. (2003): the role of complex sedimentological research in solving general problems of the dinaric ophiolite zone.– rad hazu, 486, 27, 111–129. tišljar, j. (2005): geologija središnjeg velebita.– lička revija, 5, 12–26. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeography, palaeoclimatology, palaeoecology, 220, 333–360. elsevier tišljar, j., veseli, v., vlahović, i. & koch, g. (2008): permian and mesozoic deposits in well mudawara–1 (aphamia, syria): new sedimentological data based on the core reinterpretation.– nafta, 59/4, 180–194. review papers vlahović, i., tišljar, j., matičec, d., & velić, i. (2005): geologija.– in: matijašić, m. & bertoša, m. (eds.): istarska enciklopedija. leksikografski zavod »m. krleža«, zagreb, 248–249. igor vlahović, ivo velić & branko sokač: in memoriam academician josip tišljar (1941–2009) geologia croatica 121 conference presentations *proceedings; **abstract-books * tišljar, j. (1976): lagunski, potplimni, međuplimni i natplimni karbonatni sedimenti valendis–otriva zapadne istre.– in: referati ii skupa sedimentologa sfrj. beograd, 155–174. * sokač, b., velić, i. & tišljar, j. (1978): model biostratigrafskog rasčlanjivanja i analize sredina taloženja u karbonatnim sedimentima donje krede biokova.– in: zbornik radova ix kongresa geologa sfrj. sarajevo, 226–233. * blašković, i., tišljar, j. & velić, j. (1980): sedimentološke i paleogeografske značajke naslaga donjeg sarmata jugozapadnih obronaka psunja.– in: bilten »20 godina lmgk«. beograd, 11–13. * tišljar, j. (1980): peritidalne faze sedimentacije i vadozna dijageneza vapnenaca titon–berijasa okolice dubrovnika.– in: bilten »20 godina lmgk«. beograd, 55–56. * velić, i., tišljar, j. & sokač, b. (1980): metodologija i rezultati biostratigrafskih i litofacijesnih istraživanja u plitkomorskim karbonatnim sedimentima na primjeru donje krede krškog područja dinarida u hrvatskoj.– in: bilten »20 godina lmgk«. beograd, 57–58. ** tišljar, j., đurasek, n., sokač, b. & velić, i. (1981): facijesna korelacija donje krede jadranskog područja.– in: sažeci predavanja simpozija »kompleksna naftno-geološka problematika podmorja i priobalnih dijelova jadranskog mora«, split, 163–170. * tišljar, j., đurasek, n., sokač, b. & velić, i. (1981): facijesna korelacija donje krede jadranskog područja.– in: zbornik radova znan. simpozija »naftno-geološka problematika podmorja i priobalnih dijelova jadranskog mora«. jazu, zagreb, 163–171. ** tišljar, j., velić, i. & sokač, b. (1982): flachwasserkarbonate der unterkreide im dinarischen karstgebiet entlang der jugoslawischen adriaküste..– in: 2. internationale sympozium – kreide, abstracts. münchen, 81–82. ** blašković, i., tišljar, j., dragičević, i. & velić, j. (1983): dinamics of turbidity fans of the early neogene deposits in the western slopes of the early neogene deposits of the psunj mt. (eastern croatia).– in: jelaska, v. & tišljar, j. (eds.): 4th regional meeting i.a.s., abstracts. international assoc. of sedimentologists, split, 25–27. ** dimitrijević, m., dimitrijević, m., tišljar, j. & pantićprodanović, s. (1983): bulog formation: nodular amonitic limestones.– in: jelaska, v. & tišljar, j. (eds.): 4th regional meeting i.a.s., abstracts. international assoc. of sedimentologists, split, 51–53. ** jelaska, v., tišljar, j. & velić, i. (1984): upper cretaceous carbonate platform units of the adriatic sea.– in: 27th international geol. congres. abstracts, ii. moscow, 80–81. ** blašković, i., dragičević, i., tišljar, j. & velić, j. (1985): the badenian submarine fan-delta in the mt. psunj (croatia).– in: 6th european regional meeting i.a.s. abstracts. international assoc. of sedimentologists, lleida, spain, 518–522. ** tišljar, j., velić, i. & sokač, b. (1985): facies and environmental characteristics of the jurassic carbonate sediments from the southern adriatic (yugoslavia).– in: 6th european regional meeting i.a.s. abstracts. international assoc. of sedimentologists, lleida, spain, 686–690. ** blašković, i., dragičević, i. & tišljar, j. (1986): on mechanism of deposition of the promina formation conglomerates in the mesihovina–rakitno basin (western herzegovina).– in: 7th regional european meeting of i.a.s., abstracts. international assoc. of sedimentologists, krakow, 195–199. ** tišljar, j. (1986): origin of the black pebbles of some jurassic and cretaceous carbonate units of the coastal dinarides (yugoslavia).– in: sažeci predavanja v skupa sedimentologa sfrj. 1–6, brijuni. ** dragičević, i., blašković, i., tišljar, j. & papeš, j. (1987): the eocene bioherms and the associated lithofacies in western herzegovina (yugoslavia).– in: 8th regional meeting of i.a.s., abstracts. international assoc. of sedimentologists, tunis, 199–204. ** velić, i., tišljar, j. & sokač, b. (1987): the variability of thicknesses of the aptian and albian carbonates as a consequence of changing depositional environments and emersions.– in: internat. symposium of the »evolution of the karstic carbonate platform: relation with other periadriatic carbonate platforms«, abstracts. trieste, 59–62. * raškaj, n., tadej, j., tišljar, j. & levašić, e. (1990): razvoj transgresivnih litofacijesa tercijarnih naslaga u bušotini đeletovci– 38 naftnog polja đeletovci (istočna slavonija).– in: xii kongres geologa jugoslavije, knj. i – stratigrafi ja, sedimentologija, paleontologija, ohrid. geološko društvo na makedonija, skopje, 291–301. ** tišljar, j., velić, i. & vlahović, i. (1991): peritidal sequences and cycles in the jurassic and cretaceous of the adriatic carbonate platform.– in: dolomieu conference an carbonate platforms and dolomitization, abstracts. val gardena/grödental, ortisei/st. urlich, 271–272. ** veseli, v., tišljar, j., tadej, j. & premec-fuček, v. (1991): lithofacies and biofacies of the cretaceous and paleogene carbonate sediments in kate–1 offshore well (kornati area, croatia, adriatic sea).– in: velić, i. & vlahović, i. (eds.): second internat. symposium on the adriatic carbonate platform, abstracts. institute of geology, zagreb, 115–116. ** hernitz, z., tišljar, j., kalac, k., velić, j. & jelić, k. (1993): miocenski siparni i priobalni klastiti te matične stijene u dravskoj depresiji.– in: savjetovanje o kolektorskim stijenama u panonskom bazenu, sažeci predavanja. zagreb, hazu 1–2. ** pikija, m., šikić, k., tišljar, j. & hrabak, n. (1993): stratigrafske, paleogeomorfološke i sedimentacijske značajke miocena područja molve–kalinovac.– in: savjetovanje o kolektorskim stijenama u panonskom bazenu, sažeci predavanja. hazu, zagreb, 7–8. ** tišljar, j. (1993): oblici sedimentnih tijela i modeli taloženja badenskih naftonosnih naslaga područja beničanaca, ladislavaca i oboda.– in: savjetovanje o kolektorskim stijenama u panonskom bazenu, sažeci predavanja. hazu, zagreb, 3–4. ** tišljar, j. (1994): uloga i važnost kompleksnih istraživanja facijesa pri potencijalnosti ležišta arhitektonskog kamena.– in: simpozij: »prirodni arhitektonski kamen od ležišta do ugradnje (kamen u hrvatskom nasljeđu)«, prošireni sažeci predavanja. rgnf, zagreb, 13–15. ** tišljar, j. velić, i. & vlahović, i. (1994): correlation of the upper jurassic carbonate platform deposits in western croatia.– in: first international meeting on perimediterranean carbonate platforms, abstracts. marseille, 153–156. ** velić, i., vlahović, i. & tišljar, j. (1994): relationship of peritidal and reefal inner carbonate ramp facies in the upper jurassic of the gorski kotar area (croatia).– in: first international meeting on perimediterranean carbonate platforms, abstracts. marseille, 157–160. ** vlahović, i., tišljar, j. & velić, i. (1994): facies succession in the cenomanian of istria (western croatia): tectonic vs. eustatic control.– in: first international meeting on perimediterranean carbonate platforms, abstracts. marseille, 169–171. ** tišljar, j., velić, i. & vlahović, i. (1995): usporedba gornjojurskih karbonatnih platformnih naslaga zapadne hrvatske.– in: vlahović, i., velić, i. & šparica, m. (eds.): 1. hrvatski geološki kongres, knjiga sažetaka. institute of geology, zagreb, 93. ** velić, i., tišljar, j. & vlahović, i. (1995): jesu li vapnenci s rožnjacima u gornjoj juri gorskog kotara »lemeš naslage«?– in: geologia croatica 63/1geologia croatica 122 vlahović, i., velić, i. & šparica, m. (eds.): 1. hrvatski geološki kongres, knjiga sažetaka. institute of geology, zagreb, 96. ** velić, i., vlahović, i. & tišljar, j. (1995): odnos facijesa peritajdala, prigrebena i unutarnje karbonatne rampe u gornjoj juri gorskoga kotara.– in: vlahović, i., velić, i. & šparica, m. (eds.): 1. hrvatski geološki kongres, knjiga sažetaka. institute of geology, zagreb, 96. ** vlahović, i., tišljar, j. & velić, i. (1995): slijed facijesa u cenomanu istre: tektonika ili eustatička uvjetovanost.– in: vlahović, i., velić, i. & šparica, m. (eds.): 1. hrvatski geološki kongres, knjiga sažetaka. institute of geology, zagreb, 99. ** vlahović, i., tišljar, j., velić, i., fuček, l., oštrić, n. & prtoljan, b. (1995): o podrijetlu i značenju tzv. vapnenačko– dolomitnih breča između donje i gornje krede: primjer ćićarije.– in: vlahović, i., velić, i. & šparica, m. (eds.): 1. hrvatski geološki kongres, knjiga sažetaka. institute of geology, zagreb, 99. ** durn, g., ottner, f., tišljar, j., schwaighofer, b. & müller, h.w. (1997): clay mineral assemblages in pelitic material associated with subaerial unconformities in early cretaceous shallow-water carbonate sediments in istria, croatia.– in: the 11th international clay conference, clays for our future, abstracts. otawa, a25. ** ottner, f., durn, g., tišljar, j., schwaighofer, b. & müller, h.w. (1997): pelitic material associated with subaerial unconformites in the early cretaceous in istria, croatia: sediments or paleosols?– in: european union of geosciences – eug 9, abstract supplement no 1, terra nova, 9. strasbourg, 407–408. ** ottner, f., durn, g., tišljar, j., schwaighofer, b. & müller, h.w. (1997): pelitic material associated with subaerial unconformites in the early cretaceous of croatia: sediments or paleosoils?– in: inter. working meeting of isss–commission v and inqua–commission on peleopedology: recent and paleo– pedogenesis as tools for modelling past and future global change. abstracts. giessen, 38. ** vlahović, i, matičec, d., velić, i. & tišljar, j. (1997): tectonic dynamics during the cretaceous in the istrian part of the adriatic carbonate platform (nw croatia).– in: internat. meeting riunione scientifi ca dei ricercatori alpini e appeninnici – »gruppo alpi«. riassunti, udine, 39. ** mesić, i., hernitz, z. tišljar, j. & barić, v. (1998): the ladislavci field – tectonics, lithofacies relations and 3d seismics.– in: 60th eage conference and technical exhibition – petroleum division, extended abstracts book, 2. european association of geoscientists engineers, leipzig, 550–553. ** ottner, f., durn, g., schwaighofer, b. & tišljar, j. (1998): clay minerals in paleosols of cretaceous age in istria, croatia.– in: inter. symposium and field workshop on paleosols and climatic change. abstracts. inter. soc. of soil science – paleopedology commission, lanzhou, china, 44. ** ottner, f., durn, g., schwaighofer, b., fröschl, h. tišljar, j. (1999): illitization of smectites in paleosols from istria, croatia.– in: conference of the european clay groups assoc., euroclay 1999, abstracts, kraków. * aljinović, d. tišljar, j. (2000): razvoj karbonatnih i sili ciklastičnih facijesa donjega trijasa gorskoga kotara (hrvatska).– in: vlahović, i. & biondić, r. (eds.): 2. hrvatski geol. kongres, cavtat–dubrovnik, zbornik radova. institut za geološka istraživanja, zagreb, 65–68. ** durn, g., ottner, f., tišljar, j., schwaighofer, b., fröschl, h. & ćović, m. (2000): mineraloški, mikromorfološki i geokemijski pokazatelji pedogenetske prirode glina vezanih na regionalnu emerziju u mlađem aptu i starijem albu u istri, hrvatska.– 2. hrvatski geol. kongres, cavtat–dubrovnik, zbornik radova. institut za geološka istraživanja, zagreb, 503–504. ** aljinović, d. & tišljar, j. (2001): pretplatformni megafacijesi od karbona do srednjega trijasa krškoga područja dinarida.– 2. hrvatski geol. kongres, cavtat–dubrovnik, zbornik radova. institut za geološka istraživanja, zagreb, 9–16. ** matičec, d., vlahović, i., velić, i. & tišljar, j. (2001): sinsedimentacijska tektonika na jadranskoj karbonatnoj platformi.– in: dragičević, i. & velić, i. (eds.): karbonatna platforma ili karbonatne platforme dinarida – knjiga sažetaka. rudarsko-geološko-naftni fakultet, zagreb, 46–50. ** tišljar, j. & vlahović, i. (2001): dolomitizacija i dolomiti unutar platformnih karbonata krškog područja dinarida.– in: dragičević, i. & velić, i. (eds.): karbonatna platforma ili karbonatne platforme dinarida – knjiga sažetaka. rudarskogeološko-naftni fakultet, zagreb, 38–40. ** tišljar, j., velić, i. & vlahović, i. (2001): makrofacijesi gornjotrijaskih, jurskih, krednih i paleogenskih platformnih karbonata krškog područja dinarida.– in: dragičević, i. & velić, i. (eds.): karbonatna platforma ili karbonatne platforme dinarida – knjiga sažetaka. rudarsko-geološko-naftni fakultet, zagreb, 41–45. ** vlahović, i., velić, i., tišljar, j. & matičec, d. (2001): utjecaj sinsedimentacijske tektonike na malmsku paleogeografi ju jadranske karbonatne platforme.– in: dragičević, i. & velić, i. (eds.): karbonatna platforma ili karbonatne platforme dinarida – knjiga sažetaka. rudarsko-geološko-naftni fakultet, zagreb, 51–54. ** fuček, l., vlahović, i., tišljar, j., velić, i., husinec, a., korbar, t., matičec, d., oštrić, n., prtoljan, b., palenik, d. & ibrahimpašić, h. (2003): dynamics of latest albian–cenomanian sedimentary environments in the nw part of the adriatic carbonate platform (istria and northern adriatic islands, croatia).– in: vlahović. i. (ed.): abstracts book of the 22nd ias meeting of sedimentology – opatija 2003. zagreb, 60. tišljar, j. (2003): podrijetlo i uvjeti postanka istarskog arhitektonskograđevnog kamena. – in: matekalo-draganović, j. (ed.): znanstveni skup hrvatski prirodoslovci – 12. matica hrvatska, odjel za prirodoslovlje i matematiku, zagreb, 6. ** vlahović, i., tišljar, j., velić, i. & matičec, d. (2003): large-scale facies architecture and events in the geological history of the adriatic carbonate platform.– in: vlahović. i. (ed.): abstracts book of the 22nd ias meeting of sedimentology – opatija 2003. zagreb, 215. tišljar, j. (2004): geologija središnjeg velebita. – in: matekalodraganović, j. (ed.): znanstveni skup: hrvatski prirodoslovci 13. – sažeci radova. matica hrvatska, odjel za prirodoslovlje i matematiku, zagreb, 26–27. velić, i., tišljar, j., vlahović, i., matičec, d. & bergant, s. (2004): introduction to the adriatic carbonate platform.– in: guerrieri, l., rischia, i. & serva, l. (eds.): adriatic–dinaridic mesozoic carbonate platform, environments and facies from permian to recent time, 32nd international geological congress, florence august 20–28, 2004, field trip guide book. apat – italian agency for the environmental protection and technical services, roma, 3–7. ** vlahović, i., tišljar, j. & velić, i. (2004): palaeogeographic signifi cance of dinosaur occurrences on the isolated adriatic carbonate platform (w croatia, ne italy, sw slovenia) from the tithonian to campanian/maastrichtian.– in: abstracts book 23rd ias meeting coimbra–portugal. ias, coimbra, 283. ** mileusnić, m., durn, g., ottner, f., fröschl, h. & tišljar, j. (2005): late aptian and early albian regional emersion phase in istria, croatia.– in: 7th international symposium on the cretaceous – scientifi c program and abstracts. neuchatel, 142. igor vlahović, ivo velić & branko sokač: in memoriam academician josip tišljar (1941–2009) geologia croatica 123 * tadej, j. & tišljar, j. (2005): petrološko-sedimentološka interpretacija jezgara bušotine molve–29.– in: velić, i., vlahović, i. & biondić, r. (eds.): 3. hrvatski geološki kongres, vodič ekskurzija. hrvatski geološki institut, zagreb, 4–8. ** tišljar, j., vlahović, i. & velić, i. (2005): paleogeografi ja i okoliši taloženja u juri zapadnog dijela jadranske karbonatne platforme na području hrvatske.– in: velić, i., vlahović, i. & biondić, r. (eds.): 3. hrvatski geološki kongres – opatija 2005, knjiga sažetaka. hrvatski geološki institut, zagreb, 155–157. * durn, g., ottner, f., mindszenty, a., tišljar, j. & mileusnić, m. (2006): clay mineralogy of bauxites and palaeosols in istria formed during regional subaerial exposures of the adriatic carbonate platform.– in: 3rd mid-european clay conference: field trip guidebook. university of zagreb, faculty of science, faculty of mining, geology and petroleum engineering, zagreb, 3–30. ** tišljar, j., veseli, v., & vlahović, i. (2006): sedimentological interpretations of the permian and mesozoic deposits from the mudawara–1 well cores (aphamia – syria).– in: 4th international symposium on petroleum geology, sažeci. hazu znanstveno vijeće za naftu, eage, rudarsko-geološko-naftni fakultet sveučilišta u zagrebu, zagreb, 40–47. * velić, i., vlahović, i., tišljar, j. & matičec, d. (2006): introduction to the stratigraphy of the karst (outer) dinarides.– in: adria 2006. field trip guide. universita degli studi di urbino, urbino, 15–17. * velić, i., vlahović, i., tišljar, j., sremac, j. & matičec, d. (2006): middle permian clastic deposits; carbonate succession middle–upper permian; clastic–carbonate deposits of middle–upper triassic (ladinian–norian); lower jurassic shallow-marine carbonates (hettangian to pliensbachian); lower jurassic bioturbated limestones (toarcian); oligocene–miocene jelar breccia.– in: adria 2006. field trip guidebook. universita degli studi di urbino, urbino, 51–58. * veseli, v., velić, i., vlahović, i., tišljar, j., stanković, d. (2006): biozonation of sinemurian and pliensbachian larger benthic foraminifera (velebit mt., croatia).– in: anuario do instituto de geociencias – ufrj, vol. 20–1, rio de janeiro. universidade federal do rio de janeiro, centro de ciencias matem. a da natureza, instituto de geociencias, rio de janeiro, 368–369. ** vlahović, i., tišljar, j., velić, i. & matičec, d. (2007): immense tertiary carbonate jelar breccia, dinarides, croatia: a new view.– in: 2007 gsa denver annual meeting and exhibition: geological society of america, abstracts with programs. geological society of america, denver, 146. **mileusnić, m., durn, g., ottner, f., tišljar, j., aljinović, d. & barudžija, u. (2008): origin of clayey materials deposited during aptian/albian emersion in istria, croatia.– in: gorniak, k. & szydlak, t. (eds.): mineralogia – special papers zakopane. mineralogical society of poland, zakopane, 115. vranjković, a., tišljar, j., dragičević, i., pavelić, d., mandić, o., sprovieri, m., harzhauser, m., lirer, f. & tadej, n. (2009): microfacies analysis and stable isotope record from continental freshwater lacustrine carbonates (early–middle miocene, sinj basin, se croatia).– in: pascucci, v. & andreucci, s. (eds.): sedimentary environments of mediterranean island(s). edes–editrice democratica sarda, sassari, 402. books tišljar, j. (1987): petrologija sedimentnih stijena.– rudarskogeološko-naftni fakultet zagreb, tehnička knjiga, zagreb, 242 p. tišljar, j. (1994): sedimentne stijene.– školska knjiga., zagreb, 422 p. tišljar, j. (1999): petrologija s osnovama mineralogije.– rudarskogeološko-naftni fakultet, zagreb, 211 p. tišljar, j. (2001): sedimentologija karbonata i evaporita.– institut za geološka istraživanja, zagreb, 375 p. tišljar, j. (2004): sedimentologija klastičnih i silicijskih taložina.– institut za geološka istraživanja, zagreb, 426 p. chapters in books tišljar, j. & šimunić, al. (1978): maceljski pješčenjaci.– in: vodič ekskurzije iii skupa sedimentologa sfrj. hrvatsko geološko društvo, zagreb, 32–37. radovčić, j., tišljar, j. & jelaska, v. (1983): upper cretaceous fi sh-bearing platy limestones in central dalmatia.– in: babić, lj. & jelaska, v. (eds.): contribution to sedimentology of some carbonate and clastic units of the coastal dinarides, excursion guide–book, 4th i.a.s. regional meeting. international assoc. sedimentologists, split, 79–85. tišljar, j. (1983): coated grains facies in the lower cretaceous of the outer dinarides (yugoslavia).– in: peryt, t. (ed.): coated grains. springer-verlag, berlin–heidelberg–new york–tokyo, 566–576. tišljar, j., velić, i., radovčić, j. & crnković, b. (1983): upper jurassic and cretaceous peritidal, lagoonal, shallow marine and perireefal sediments of istria. – in: babić, lj. & jelaska, v. (eds.): contribution to sedimentology of some carbonate and clastic units of the coastal dinarides, excursion guide–book, 4th i.a.s. regional meeting. international assoc. sedimentologists, split, 13–35. tišljar, j. & velić, i. (1986): ritmična sedimentacija u peritidalnim i lagunskim karbonatnim sedimentima donje krede istre.– in: vodič ekskurzije v skupa sedimentologa sfrj, brijuni. hrvatsko geološko društvo, zagreb, 1–27. tišljar, j., vlahović, i., sremac, j., velić, i., veseli, v. & stanković, d. (1991): the middle permian calcispongite patchreef, permian peritidal carbonates, middle to upper triassic shallow-marine limestones and continental sediments, liassic shallowmarine, tempestite and bioturbated limestones – excursion a – velebit mt.: permian–jurassic.– in: vlahović, i. & velić, i. (eds.): some aspects of the shallow water sedimentation on the adriatic carbonate platform (permian to eocene). excursion guidebook, second internat. symposium on the adriatic carbonate platform. institute of geology, zagreb, 3–52. fuček, l., tišljar, j., sokač, b., prtoljan, b. & oštrić, n. (1995): gornjotrijaski dolomiti u kamenolomu podsused.– in: šikić, k. (ed.): geološki vodič medvednice. institut za geološka istraživanja, zagreb, 41–43. pikija, m., šikić, k., tišljar, j. & miknić, m. (1995): miocenski sedimenti uz trasu zelene magistrale.– in: šikić, k. (ed.): geološki vodič medvednice. institut za geološka istraživanja, zagreb, 49– 51. prtoljan, b., fuček, l. & tišljar, j. (1995): metamorfozirani paleozojski vapnenci pokraj planinarskog doma grafi čar.– in: šikić, k. (ed.): geološki vodič medvednice. institut za geološka istraživanja, zagreb, 84–85. prtoljan, b., oštrić, n., fuček, l., velić, i. & tišljar, j. (1995): mezozojske vapnenačke stijene u predjelu horvatove stube–markov travnik.– in: šikić, k. (ed.): geološki vodič medvednice. institut za geološka istraživanja, zagreb, 137–139. tišljar, j., vlahović, i., matičec, d. & velić, i. (1995): platformni facijesi od gornjega titona do gornjeg alba u zapadnoj istri i prijelaz u tempestitne, klinoformne i rudistne biolititne facijese donjega cenomana u južnoj istri (ekskurzija b).– in: vlahović, i. & velić, i. (ed.): 1. hrvatski geološki kongres, vodič ekskurzija. institut za geološka istraživanja, zagreb, 67–110. velić, i., matičec, d., vlahović, i. & tišljar, j. (1995): stratigrafski slijed jurskih i donjokrednih karbonata (bat–gornji alb) u geologia croatica 63/1geologia croatica 124 zapadnoj istri (ekskurzija a).– in: vlahović, i. & velić, i. (ed.): 1. hrvatski geološki kongres, vodič ekskurzija. institut za geološka istraživanja, zagreb, 31–66. velić, i., tišljar, j., matičec, d. & vlahović, i. (1995): opći prikaz geološke građe istre.– in: vlahović, i. & velić, i. (ed.): 1. hrvatski geološki kongres, vodič ekskurzija. institut za geološka istraživanja, zagreb, 5–30. vlahović, i., velić, i., tišljar, j. & matičec, d. (1999): lias carbonate platform deposits of velebit mt. (croatia).– in: harold reading’s ias lecture tour ’99 – croatia: some carbonate and clastic successions of the external dinarides – velebit mt., island of rab, field-trip guidebook. institute of geology, faculty of sciences croatian geological society, zagreb, 9–22. vlahović, i., velić, i., tišljar, j. & matičec, d. (1999): lithology and origin of tertiary jelar breccia within the framework of tectogenesis of dinarides.– in: harold reading’s ias lecture tour ’99 – croatia: some carbonate and clastic successions of the external dinarides – velebit mt., island of rab, field-trip guidebook. institute of geology, faculty of sciences, croatian geological society, zagreb, 23–25. matičec, d., vlahović, i., fuček, l., oštrić, n., prtoljan, b. & tišljar, j. (2000): strutture del margine nord-orientale delle istria: la regione del monte maggiore (učka) e della ciceria (ćićarija).– in: carulli, g.b. (ed.): le piattaforme carbonatiche giurassiche e cretaciche. guida alle escursioni; escursione b3; 80a riunione estiva, trieste. societa geologica italiana, trieste, 275–277. tišljar, j., vlahović, i., velić, i. & matičec, d. (2000): cicli peritidali berriasiani – cava fantazija presso rovigno/rovinj.– in: carulli, g.b. (ed.): le piattaforme carbonatiche giurassiche e cretaciche. guida alle escursioni; escursione b3; 80a riunione estiva, trieste. societa geologica italiana, trieste, 253–256. tišljar, j., vlahović, i., velić, i. & matičec, d. (2000): la successione di litofacies dell` allbiano superiore–cenomaniano medio delle istria meridionale – baja di bagnole (banjole) e vincurano (vinkuran).– in: carulli, g.b. (ed.): le piattaforme carbonatiche giurassiche e cretaciche. guida alle escursioni; escursione b3; 80a riunione estiva, trieste. societa geologica italiana, trieste, 262–269. velić, i., tišljar, j., matičec, d. & vlahović, i. (2000): introduzione alla geologia dellc istria.– in: carulli, g.b. (ed.): le piattaforme carbonatiche giurassiche e cretaciche, guida alle escursioni; escursione b3; 80a riunione estiva, trieste. societa geologica italiana, trieste, 237–245. vlahović, i., tišljar, j., velić, i. & matičec, d. (2000): accumuli bauxitici e cicli peritidali shallowing-upwards del giurassico superiore – dintorini di rovigno/rovinj.– in: carulli, g.b. (ed.): le piattaforme carbonatiche giurassiche e cretaciche, guida alle escursioni; escursione b3; 80a riunione estiva, trieste. societa geologica italiana, trieste, 245–253. vlahović, i., tišljar, j., velić, i. & matičec, d. (2000): lacuna di importanca regionale correspondente all` intervallo aptiano superiore–albiano superiore: limite tra la seconda e la terza megasequenza – canfanaro (kanfanar).– in: carulli, g.b. (ed.): le piattaforme carbonatiche giurassiche e cretaciche. guida alle escursioni; escursione b3; 80a riunione estiva, trieste. societa geologica italiana, trieste, 269–275. vlahović, i., velić, i., tišljar, j. & matičec, d. (2000): liassic carbonate platform deposits of the velebit mt. (croatia).– in: pamić, j. & tomljenović, b. (eds.): pancardi 2000. hrvatsko geološko društvo, zagreb, 127–134. korbar, t., skelton, p.w., tišljar, j., moro, a., vlahović, i., velić, i. & fuček, l. (2002): middle to upper cenomanian transition: high-energy shoals with recumbent rudists to relatively low-energy environments with elevator rudists in southern istria (gomila, tašalera and fenoliga islet).– in: vlahović, i. & korbar, t. (eds.): 6th international congress on rudists, rovinj, abstracts and excursion guidebook. institute of geology, zagreb, 111–122. moro, a., korbar, t., skelton, p.w., velić, i., tišljar, j., vlahović, i., fuček, l., matičec, d. & ćosović, v. (2002): upper santonian rudist-bearing lithosomes formed in the transition from deeper to shallower subtidal environments at cape marlera and učka mountain.– in: vlahović, i. & korbar, t. (eds.): 6th international congress on rudists, rovinj, abstracts and excursion guidebook. institute of geology, zagreb, 133–139. tišljar, j., vlahović, i., skelton, p.w., korbar, t., moro, a., velić, i. & matičec, d. (2002): upper albian to middle cenomanian facies evolution with extensive rudist production in southern istria (banjole, vinkuran and frašker island).– in: vlahović, i. & korbar, t. (eds.): 6th international congress on rudists, rovinj, abstracts and excursion guidebook. institute of geology, zagreb, 101–109. tišljar, j., vlahović, i., skelton, p.w., moro, a., korbar, t. & velić, i. (2002): turonian vast production and progradation of rudist shells and debris (valtura quarry, southern istria).– in: vlahović, i. & korbar, t. (eds.): 6th international congress on rudists, rovinj, abstracts and excursion guidebook. institute of geology, zagreb, 129–132. velić, i., tišljar, j., vlahović, i., matičec, d., korbar, t. & moro, a. (2002): aptian deposits with requieniids below a late aptian–early albian regional emersion surface (kanfanar and dvigrad, central istria).– in: vlahović, i. & korbar, t. (eds.): 6th international congress on rudists, rovinj, abstracts and excursion guidebook. institute of geology, zagreb, 83–93. velić, i., tišljar, j., vlahović, i., matičec, d., korbar, t., moro, a. & ćosović, v. (2002): geological evolution of istria (nw part of the adriatic carbonate platform, croatia).– in: vlahović, i. & korbar, t. (eds.): 6th international congress on rudists, rovinj, abstracts and excursion guidebook. institute of geology, zagreb, 83–93. vlahović, i., korbar, t., moro, a., velić, i., skelton, p.w., fuček, l. & tišljar, j. (2002): latest cenomanian to earliest turonian platform drowning and turonian recovery of shallowwater platform deposition in southern istria.– in: vlahović, i. & korbar, t. (eds.): 6th international congress on rudists, rovinj, abstracts and excursion guidebook. institute of geology, zagreb, 95–100. bergant, s., tišljar, j. & šparica m. (2003): eocene carbonates and fl ysch deposits of the pazin basin.– in: vlahović, i. & tišljar, j. (eds.): evolution of depositional environments from the palaeozoic to the quaternary in the karst dinarides and pannonian basin, 22nd ias meeting of sedimentology – opatija 2003, excursion guide-book. institute of geology, zagreb, 57–64. durn, g., ottner, f., tišljar, j., mindszenty, a. & barudžija, u. (2003): regional subaerial unconformities in shallowmarine carbonate sequences of istria: sedimentology, mineralogy, geochemistry and micromorphology of associated bauxites, palaeosols and pedo-sedimentary complexes.– in: vlahović, i. & tišljar, j. (eds.): evolution of depositional environments from the palaeozoic to the quaternary in the karst dinarides and pannonian basin, 22nd ias meeting of sedimentology – opatija 2003, excursion guide-book. institute of geology, zagreb, 209–255. pavelić, d., kovačić, m., miknić, m., avanić, r., vrsaljko, d., bakrač, k., tišljar, j., galović, i. & bortek, ž. (2003): the evolution of the miocene environments in the slavonian mts. area (northern croatia).– in: vlahović, i. & tišljar, j. (eds.): evolution of depositional environments from the palaeozoic to the quaternary in the karst dinarides and pannonian basin, 22nd ias meeting of sedimentology – opatija 2003, excursion guide-book. institute of geology, zagreb, 173–182. igor vlahović, ivo velić & branko sokač: in memoriam academician josip tišljar (1941–2009) geologia croatica 125 velić, i., tišljar, j., vlahović, i., matičec, d. & bergant, s. (2003): evolution of istrian part of the adriatic carbonate platform from the middle jurassic to the santonian and formation of the fl ysch basin during the eocene: main events and regional comparison.– in: vlahović, i. & tišljar, j. (eds.): evolution of depositional environments from the palaeozoic to the quaternary in the karst dinarides and pannonian basin, 22nd ias meeting of sedimentology – opatija 2003, excursion guide-book. institute of geology, zagreb, 3–18. vlahović, i., tišljar, j., velić, i., matičec, d., skelton, p.w., korbar, t. fuček, l. (2003): main events recorded in the sedimentary succession of the adriatic carbonate platform from oxfordian to the upper santonian in istria (croatia).– in: vlahović, i. & tišljar, j. (eds.): evolution of depositional environments from the palaeozoic to the quaternary in the karst dinarides and pannonian basin, 22nd ias meeting of sedimentology – opatija 2003, excursion guide-book. institute of geology, zagreb, 19–56. juračić, m., palinkaš, l., bajraktarević, z., buljan, r., bergant, s., jurak, v., gušić, i., marjanac, lj., marjanac, t., matičec, d., mezga, a., paviša, t., šes ta nović, s., šoštarić-borojević, s., strmić, s., sremac, j., tišljar, j. & vlahović, i. (2004): adriatic–dinaridic mesozoic carbonate platform, environments and facies from permian to recent time – field trip guide book. – apat – italian agency for the environmental protection and technical services, roma, 1–48. grgasović, t., koch, g. & tišljar, j. (2007): carnian strata – slapnica valley (žumberak–samoborsko gorje nature park).– in: grgasović, t. & vlahović, i. (eds.): 9th international symposium on fosil algae, field trip guidebook and abstracts. hrvatski geološki institut, zagreb, 183–189. tišljar, j., velić, i., vlahović, i., sokač, b. & grgasović, t. (2007): middle to upper triassic shallow-marine limestones and continental sediments with bauxite, vrace near gračac (velebit mt.).– in: grgasović, t. & vlahović, i. (eds.): 9th international symposium on fosil algae, field trip guidebook and abstracts. hrvatski geološki institut, zagreb, 121–125. velić, i., vlahović, i., tišljar, j., & matičec, d. (2007): oligocene–miocene jelar breccia (mt. velebit).– in: grgasović, t. & vlahović, i. (eds.): 9th international symposium on fosil algae, field trip guidebook and abstracts. hrvatski geološki institut, zagreb, 57–59. velić, i., tišljar, j. & vlahović, i. (2009): tercijarne karbonatne breče (paleogen, neogen – pg, ng).– in: velić, i. & vlahović, i. (eds.): tumač geološke karte republike hrvatske 1:300.000. hrvatski geološki institut, zagreb, 80–81. vlahović, i., tišljar, j. & velić, i. (2009): dolomiti i postsedimentacijske dijagenetske breče (gornji alb, donji cenoman – k1 6, k2 1).– in: velić, i. & vlahović, i. (eds.): tumač geološke karte republike hrvatske 1:300.000. hrvatski geološki institut, zagreb, 65–66. 1. introduction at podsused near zagreb, in an abandoned surface excavation of cement marls, near kostanjek (fig. 1) an 83 m thick lithostratigraphical column was investigated comprising layers of sarmatian and pannonian age. five lithofacies units (a, ab, b, c, d) were separated on the basis of their structural-petrographic characteristics. from layers with greater concentrations of fossils, a rich community of molluscs, foraminifera and ostracods was sampled, from which three basic biofacies were distinguished and the sediment age was defined. in summary, 23 gastropod species (21 of pannonian and 2 of sarmatian age) and 27 bivalve species the pannonian palaeoecology and biostratigraphy of molluscs from kostanjek medvednica mt., croatia davor vrsaljko (24 of pannonian and 3 of sarmatian age) were determined. within the mollusc association various forms were detected: from facies and zonal to transitional and endemic species, as well as species with opportune and equilibrium characteristics. without discussing the chronostratigraphic division of the younger miocene layers, the interpretation of the sarmatian stage was accepted according to sene© & papp (1974), and the pannonian (table 1) partially according to papp (1951, 1953) and stevanovi∆ (1957, 1985), and mostly according to the division of croatian geologists, used for the “basic geological maps” (©iki∆ et al., 1978, 1979). in the middle of the sarmatian (bessarabian), the western areas of paratethys were being separated by a natural barrier i.e. the carpathian arch, from eastern back-carpathian parts, and a distinct sedimentary environment called the pannonian basin, was being formed (stevanovi∆, 1985). as the marine cycle of sedimentation continued into the eastern parts (sarmatian sensu lato, according to barbot de marny) in the pannonian basin, a considerable desalinization of the water occurred, under which regime, layers with separate lithological and faunistic content were being formed. these layers are defined as a separate stage, the pannonian. the early pannonian substage approximately corresponds to the period of the upper part of the middle and late sarmatian (sensu lato), while the late pannonian substage is equivalent to the meotian stage of eastern areas (stevanovi∆, 1985). among the numerous authors who wrote about the biostratigraphy of the pannonian strata, papp’s research is significant. thus, papp (1951, 1953) divided the pannonian layers on the basis of molluscs into several biozones: a) gravel and sand with r e p l i d a c n a, b) sand with melanopsis impressa and congeria ornithopsis , c) sand with m. fossilis and c. partschi , d) sand and gravel with m. vindobonense and m. fossilis constricta, and e) clay with m. vindobonense and c. subglobosae. papp places biozones a, b, c and d to the “lower-congerian layers”, where zone a is similar to the sarmatian series (a/b), and zone e represents the “middle-congerian layers” (table 2). later, papp (1956) studied marls and gravels around podsused and correlated them to the similar layers of the vienna basin. the high content of a coarse-grained component in the vienna basin layers determined the boundary facies in which river molluscs g eol. cr oa t. 52/1 9 27 10 figs. 6 tabs. zagreb 1999 key words: mollusca, c a r d i i d a e , l y m n o c a r d i i d a e, phylogenetic series, biozone, pannonian, pannonian basin, medvednica mt., croatia. institute of geology, sachsova 2, p.o.box 268, hr-10000 zagreb, croatia. abstract on the south-western slope of medvednica mt., an 83 m thick geological column kostanjek-1, composed of strata representing the sarmatian and pannonian stages, was investigated in detail. facies analysis allowed separation of five lithofacies units (a, ab, b, c and d) and the sedimentary mechanisms for particular successions were defined. a rich community of fossil molluscs (50 species) and ostracods (42 species) was sampled and determined. from these fossil determinations, the sediment age was defined, and biofacies analysis allowed the determination of three basic palaeobiocenosis types: 1) a community from sarmatian brackish lagoons, 2) a community from an early pannonian littoral lake, and 3) a lake basin community in the late pannonian. the main “record” of the salinity crisis (drop) at the sarmatian-pannonian boundary influences in a selective way the majority of organisms, and is shown best in the evolutionary form changes of cardid bivalves, for which phylogenetic series were made. on the basis of dominant and characteristic forms in the entire association of pannonian molluscs five biozones were separated: i) lymno cardium praeponticum acrozone, ii) radix croatica l y m n o c a r d i u m plicataeformis gyraulus praeponticus cenozone, iii) neodelminiella venusta lymnocardium cekusi cenozone, iv) congeria banatica lymnocardium gorjanovici gyraulus tenuistriatus cenozone and v) congeria czjzeki lymnocardium winkleri gyraulus tenuistriatus cenozone. many ostracod forms supply and test the stratigraphic value of molluscs and support zonality of pannonian layers. 10 geologia croatica 52/1 lived, while at the same time in the more distant area around medvednica mt. a lacustrine sedimentary regime was established, and therefore, according to their faunistic content, these sediments can be compared, but with reservations (vrsaljko et al., 1995). with his studies of the central parts of the pannonian basin, stevanovi∆ (1985), completed previous divisions of the pannonian layers, differentiating basin, transitional and littoral facies (table 2), with their associated molluscan communities. this allowed further division of this stage into two substages: the lower pannonian (slavonian: early and late) and the upper pannonian (serbian). in the areas of the pannonian basin the layers are also zoned on the basis of their characteristic ostracod communities. the works of pokorny (1946) and soka» (1972, 1985) in this area are prominent. these authors, with small differences, both divide the pannonian basin (table 1) into the following biozones: α-zone with hemicitherya hungarica and miliamina subvelati na, and the β-erpetocypris abscisa zone (early pannonian), and finally the γ -cyprideis pannonica and δ erpetocypris recta zones (late pannonian). as the location of the study area (fig. 1) is palaeogeographically approximately half way between sites described by papp and stevanoviê, both results will be fig. 1 geographical location of the kostanjek1 column. used for comparison. accepting earlier stratigraphic division of the pannonian stage into substages (early and late), the results of croatian geologists will be mostly used here (jenko, 1944; oæegovi∆, 1944; kranjec et al., 1973; ©iki∆ et al., 1978, 1979). 11vrsaljko: the pannonian palaeoecology and biostratigraphy of molluscs from kostanjek... table 1 a stratigraphic correlation scheme for the younger miocene layers (compilation after sene© & papp, 1974; steininger et al., 1985; nagymarosy & müller, 1988). ! i i • i • • < • • < • • • • < • < • , , • • < , , , • • • • ~ --­~-• " • i < • < • • < • ! i i : i !i • ! • • • • , • • , • , 12 geologia croatica 52/1 table 2 biostratigraphic correlation of the pannonian strata of central and western paratethys. ~~ iil: ~ , :~ j .i ~ , ~ f · i \ i -: !: . ~ ~ ~ . ~ t~ir~ ~ .. i la~ ~ ,~ , , '!'j . , ;."':!. 'u~'i:l i;j !;.:i ~ ~ . • ii:! -4l ' , :, ii jl jl ~ '~i--~---t--i ~lim'd.jllil'il:ni (ilbbt ~1iiiii0l mj4) n ~ .t<: !l 1 ' 'qj :::o'~ ''i' ~ ._......... .._ ...... _ .... _ ...... _............. . ... _ ......... _ ......... _...... . .......... ~ ...... -............ -............ .. . ~ ~ i hh~} n .l ''iof' !j'oo .,....; ; :i ~ ':ii ~~ ~ . ...... ~ . ........., 'it \ \. ~ ' ~ ~~~ ~l.: ~~ ~j .. _ ...... _ .... _ ...... _............. . ... _ ......... _ ......... _ ................... 1 ...... _ ............ _ ............ _ .. . 'i.l. [~ i ·~ '!tu1 ~"'fam5') n:\"iswlfoaon: n\f1i8li!ib . ili1, 1 :;j,ij; r(j'1 (ml'~ ~'o\i\"ns ~ :;] 13vrsaljko: the pannonian palaeoecology and biostratigraphy of molluscs from kostanjek... 2. material and methods samples were taken in succession from sand and marls of the sarmatian and pannonian layers for palaeontological, sedimentological, petrographical and geochemical analyses. using the method of “directed dotted sample” a rich community of fossil molluscs (50 species, table 5) and ostracods (42 species, table 6) was collected from the kostanjek-1 geological column. for definition of the structural-petrographic complex of certain layers, particle analyses of the light and heavy fractions, and measurements of granulometry, sphericity and grain roundness were used. calcimetry, chemical and trace element analyses provided geochemical data. due to the large number of determined morphotypes (table 5) detailed descriptions and synonyms were avoided only the current systematic terminology has being used. after determination of the mollusc community, biofacies analyses (figs. 4-6) of individual palaeobiocenoses and biostratigraphic zoning of the pannonian layers was undertaken (fig. 2). 3. description and interpretation of the kostanjek-1 geological column 3.1. lithofacies five lithofacies units were separated in the succession (fig. 2): a) laminated silty marl , ab) l a m i n a t e d and layered marl and clay , b) layered clayey limestone and marl with sand layers , c) cross laminated gravel with sand lenses, and d) massive marl with clay layers. the laminated silty marls (a) comprise the basal lithofacies of the column, and are 1 m thick. the boundary with lithofacies ab is conformable and interfingered, marked by a 10 cm band of clay. the succession consists of rhythmical changes of very thin laminae ( 0 .1-0.5 mm): dark laminae with a greater concentration of organic matter being alternated with light laminae with a greater proportion of carbonate minerals. the average carbonate content is 40-50 %, and the concentration of strontium ( 700 ppm) and manganese ( 1500 ppm) is relatively constant (tables 3 and 4). the most frequent fossil material includes fish vertebrae and scales, ostracods, foraminifera and macroflora casts, and small gastropods and bivalves (fig. 4). the laminated marls were deposited in a relatively deep, calm and protected environment, where sedimentation was taking place from suspended flow under a regime of constant climate change (fig. 7). the probable cause of the poor fossil content is the low level of aeration (bottjer & savrda, 1990). rare, small ervilia, ostracods and foraminifera of the m i l i o l i d a e group define the sarmatian age and brackish character of the sedimentary environment. the laminated and layered marls and clay ( a b ) conformably overlie lithofacies a, and pass continuously into platy limestone (b). this lithofacies is approximately 3 m in thickness. the marls are more silty and contain 70 -80 % of the carbonate component, while clays are rich in organic detritus, granules of pyrite and limonite, and have a low carbonate content. laminae are 0.2-0.5 cm thick and layers are 5-10 cm in thickness. macrofauna remains are rare and frequently include fish fragments, while fossil grasses and continental flora also occur. small, deformed bivalve forms of the lymnocardinae subfamily, and small pond gastropods are the most frequent molluscs. large ostracods of the amplocyprisgroup also occur. the succession retains the structural complex of the sarmatian layers, but with a new type (oligohaline fig. 3) of fossil community in the early pannonian substage, which shows the constant desalinization and shallowing of the environment (vrsaljko, 1997). the cause of shallowing is most probably aggradational infilling of the sarmatian lagoon and/or lifting of the sedimentary area. disappearance of old inhabitants and their replacement by new faunistic elements is the result of the alterted water chemistry, which was closely related to regional events (sene© & papp, 1974). layered clay-limestone and marls with sand layers (b) overlie the transitional sediments (ab) in the succession. the lower boundary is conformable while the upper contact has been eroded by deposition of lithofacies c. the total thickness is 31 m. six large cycles are observed in the succession with the fining-upwards trends. layered clay-limestone in the lower part of the cycle, passes gradually upwards into silty marl with poorly visible lamination and sand layers of variable thickness. the cycles are 2 7 m thick with a higher concentration of marl, while the sand layers (lenses) are 0 .55.0 cm thick. the limestone layers have a higher concentration of carbonate ( 95%), and marls have more siliciclastic component. the sands are loosely consolidated and poorly sorted with well-rounded grains up to 0.5 mm (exceptionally up to 0.5 cm) in diameter and in parts exhibit planar cross lamination. the light mineral fraction contains quartz (35 %), feldspate ( 20 %), rock fragments (40 %) and calcite (5 %). the heavy fraction most frequently contains limonite and magnetite (15 %), dolomite (15 %), epidote (6 %) and tourmaline (3 %). the manganese content is constant ( 300 ppm), while the strontium content noticably decreases upwards, from 3,320 -710 ppm. the fossil material contains a mollusc and ostracod community representing small number of specimens of many species, together with a similar distribution of fish remains, fossil grasses, continental macroflora and frequent bioturbation (fig. 5). mollusc shells are poorly preserved because of their original aragonite composition, and the most frequent samples are pulmonate gastropods and small limnocardids. deposition of the limestone occurred during periods of low input of terrigenous particles, in contrast to the silty marls deposited from suspension during periods of 14 geologia croatica 52/1 greater siliciclastic input from the continental hinterland (fig. 8). allen & collinson (1986) reported similar results, in their research of the modern littlefield lake (michigan, usa). the origin of sand layers relates to periods of the stronger influence of fluvial processes. the rhythmic sedimentation shows the permanent relationships between subsidence, eustatic processes and the transport of material from a denuded area. a broad photic zone and global temperature decrease in the early pannonian (stevanovi∆, 1985) caused increased production of o2 and co2, which resulted in favourable conditions for the comparatively rapid settlement of “new” organisms adapting to oligohaline waters. a high concentration of strontium is more likely to be explained by the increased portion of aragonite which is linked to, and probably resulted from the dissolution of mollusc shells, rather than by the increased salinity, as shown by kranz (1976) in triassic carbonates. fig. 2 the schematic representation of the kostanjek-1 succession. 15vrsaljko: the pannonian palaeoecology and biostratigraphy of molluscs from kostanjek... the cross layered gravel with sand lenses (c) comprises three horizons approximately 2 m, 0.3 m and 8 m thick from the base to the top of the lithofacies. the lower boundary is distinctly erosional, while the upper boundary with lithofacies d is gradational. this gravel is polymict, clast-supported, trough cross-layered and normally graded. grain-size is commonly around 3 cm, exceptionally up to 15 cm. grains are semi-rounded and well sorted, and marly clasts of larger dimensions are frequent. the content of the light and heavy fractions shows great similarity with the sands of previous facies. well-rounded fragments of mollusc shells (melanopsids, congeria, cardids), occur together with algae and foraminifera that are reworked. on the basis of superpositional relationships and autochtonous molluscan community in underlying and overlying deposits of lithofacies d (congeria banatica etc.) the sediment age is defined as late pannonian. the chaotic appearance of the sediment and frequent large marl clasts indicate on the effects of seditable 3 major element composition of the marl and sand (*) samples. fig. 3 a diagram representation of salinity and species diversity (from hudson, 1990). 16 geologia croatica 52/1 ment slumping. the overlying mixed fossil community represents the allochthonous element in the given lacustrine ambient (vrsaljko et al., 1995). the lensshaped gravel bodies, structure of trough cross-bedding and gradual upward decrease in grain-size indicates a probably fluvial sedimentary origin (?fan delta). considering the size and poor roundness and sorting of the clasts, the relative proximity of the source area (e.g. medvednica mt.) can be assumed. considerable tectonic movements at the end of the early pannonian in the broad area of the pannonian basin (©iki∆ et al., 1979), were probably the trigger for the formation of these sediments, which resulted in the deepening of the lacustrine palaeoecosystem. this also increased the fluvial input of terrigenous material into the area. massive marls with clay layers ( d ) complete the succession continuously overlying the gravel of lithofacies c. this lithofacies is distinguished by the compactness of the marl layers which are more strongly bioturbated and rarely contain cm-thick clay layers. the carbonate content is constant ( 65%). there is a rich community of deep-water lacustrine bivalves and numerous ostracod forms, which together show that the sediments belong to the late pannonian substage (fig. 6). the marls and clay were deposited slowly from suspension in the deeper, more distal parts of the lake (fig. 9). primary sedimentary structures are poorly preserved due to the increased destructive activity of a benthic infauna. 3.2. biofacies in view of other biotic and abiotic ecological factors which were prevalent during the life of the organisms and which were important parameters in environmental determination (dodd & stanton, 1990), previously defined sedimentary models (figs. 7-9) were applied to the fossil community. therefore, one basic biofacies unit was separated for sediments of the sarmatian stage, and two biofacies units for the younger, pannonian stage. biofacies 1 is a fossil community of brackish lago ons (fig. 4). a sparse molluscs, ostracods and foraminifera existed in the community in thin-laminated marls and clay of the sarmatian age. the most common are molluscs ervilia and cardium, ostracods from the auri la and l o x o c o n c h a genera, and foraminifera from t h e m i l i o l i d a e and e l p h i d i u m groups. the remains of fish, macroflora and radiolarians are also common. seasonal surface suspension flows stratified the water column, weak vertical circulation and thermal stratification being formed due to differences in water density, which influenced the organic production and distribution of the biomass (dodd & stanton, 1990). a warmer surface layer was created, aerated and of decreased salinity with increased concentrations of zooand phytoplankton. the colder, deeper layer was of increased salinity supporting benthic organisms which have anaerobic respiratory characteristics (similar to the modern environment in the black sea). the degree of fossilization of skeletal parts and frequent table 4 trace element composition of the marl samples. 17vrsaljko: the pannonian palaeoecology and biostratigraphy of molluscs from kostanjek... globules of authigenic pyrite, limited by the organic carbon concentration, dissolved phosphate and terrigenous fe-minerals, illustrate a more reduced aquatic environment (allison, 1990). the sparsity of certain biogenic structures and preservation of primary lamination (bottjer & savrda, 1990), also indicate deposition in relatively deeper environment. under the deep-water anoxic conditions in which clay and marl are layered, the calcitisation of aragonitic shells ceases due to the increased concentrations of organic matter, which increased the conservation of organism skeletons (brett & speyer, 1990). biofacies 2 is composed of a littoral lacustrine c o m m u n i t y (fig. 5). the marls and limestones of the lower pannonian contain a specific, endemic association of molluscs and ostracods. endemism which devel oped in certain groups of organisms occured due to the spatial isolation of the pannonian basin (stevanovi∆, 1985) from other parts of paratethys during the pannonian. shallow carbonates of the lower pannonian supported an ostracod community which has numerous species, dominated by the hungarocypris , amplocypris, l o x o c o n c h a and c a n d o n a genera (table 6). within the mollusc community, the most numerous and most frequent are pulmonate gastropods of radix and g y r a u l u s genera and in smaller proportions representatives of l y m n o c a r d i u m, m i c r o m e l a n i a , v a l v a t a and o r y g o c e r a s (table 5). bivalves of the l y m n o c a r d i u m g e n u s here represent the derived forms from their older cardid ancestors (gorjanovi∆-kramberger, 1890), that survived the salinity crisis at the end of the sarmatian. limonitised imprints of a continental flora, swamp grass and fish skeletons are also common, while gastropods and foraminifera rarely occur in sands. aeration of the shallow water column is the cause of the increased ph (pirson, 1985) and greater concentration of dissolved gasses which participate in the formation of carbonate mud. the rich community of swamp grass supported an epibenthos herbivorous gastropod and ostracod community. the use of dissolved aragonite for the skeletal formation of most molluscs was closely connected with its increased content in this shallow water area. a considerable presence of lacustrine gastropods which breathe with their lungs presupposes constant vertical (?daily) migration of these organisms. in some shells growths shaped like hollow needles have been noticed on their ribs, and were probably used for temperature regulation. formation of secondary ribs in some shells (lymnocardium plicataefor mis and l. praeponticum) was connected with the extra strengthening of otherwise small and thin shells. biofacies 3 represents a fossil community of a lacustrine basin (fig. 6). sediments of this biofacies are represented by marls of a comparatively deeper lake. on many levels within these sediments lensoid gravel-sand bodies of fluvial origin occur. marls contain a rich autochthonous community of fossil molluscs, in which bivalves of the c o n g e r i a and l y m n o c a r d i u m fig. 4 the brackish sarmatian lagoon community. legend: a) ervilia dissita ; b) modiolus incrassatus ; c) musculus sar m a t i c u s; d) g i b b u l a sp.; e) h y d r o b i a sp.; f) cardium vindobonense; g) m a c tra vitaliana ; h) i c h n o f o s s i l s; i ) f i s h; j ) macrophyta; k) grasses; l) ostracoda; m) foraminifera; n) radiolaria. 18 geologia croatica 52/1 (sensu lato) genera dominate, and gastropods of the genera v a l e n c i e n n i u s, g y r a u l u s and r a d i x are present in smaller numbers (table 5). an abundant ostracod population contains different genera, of which in the lower parts of the column the most frequent were c a n d o n a, c y p r i a , h e m i c y t h e r i a and c y p r i d e i s, while close to the top of the column “new” representatives of the c a n d o n a subgenus were found (table 6). the marls were almost completely reworked by extensive bioturbation of various orientations, and often contain the fig. 6 the lacustrine basin community of the late pannonian. legend: a) c o n g e ria banatica ; b) congeria czjzeki; c) va l e n c i e n n i u s sp.; d) limnocardium wink l e r i ; e) limnocardium gorjanovici; f) l i m n o c a r d i um c e k u s i; g) paradacna syr m i e n s e; h) pisidium sp.; i) i c h n o f o s s i l s ; j ) watered grasses; k) fish; l) ostracoda; m) melanopsidae; n) foraminifera. fig. 5 the littoral lacustrine community of the early pannonian. legend: a) r a d i x c r o a t i c a ; b) gyraulus praeponticus ; c) micromelania striata ; d) v a l v a t a sp.; e) hydrobia sp.; f) orygoceras laevis ; g) limnocardium praeponticum; h) w a t ered grasses; i)algae (?chara ); j) fish; k) insecta; l) ostracoda; m) ichnofossils; n) continental macroflora. 19vrsaljko: the pannonian palaeoecology and biostratigraphy of molluscs from kostanjek... imprints of fish scales, continental macroflora and limonitised fossil grass. in the gravel lenses there is a mixed type of allochthonous fossil community. the large, freshwater gastropods (brusina, 1897; papp, 1956) of the melano p s i d a e are numerous (table 5), and are dispersed as bioclasts in sand. apart from gastropods there are also individual examples of bivalves with thick shell membranes (congeria partschi , c. ornithopsis ), as well as e r v i l i a, m a c t r a and o s t r e a , which are reworked from earlier sarmatian and badenian layers. algae (?l i t h o t h a m n i u m) and foraminifera from older levels are also common in the sandy matrix. this resedimented fossil community does not have particular stratigraphic value, as in the vienna basin (papp, 1953), but defines depositional processes. the aforementioned process of the deepening of the depositional system at the end of the early pannonian is here represented by the changed style of sedimentation, as well as by evolutionary changes of the pulmonate gastropods (moss, 1944) and limnocardids (fig. 10). the mollusc community (table 5) and numerous ostracod species (table 6) determine the high degree of adaptive radiation (adjustments and expansion) in new ecological environments. at the same time, the area of grass communities is decreased, and organisms adapt to a comparatively deeper, calcite-clay mud substrate. a highly oxygenated area is confirmed by the occurrence of imprints of water grasses, which need light for photosynthesis. the water grass grew distintly high and also stabilized the bottom, and herbivorous organisms fed on them. mollusc skeletons are mainly well preserved, although they had a fragile structure as a result of their predominant calcitic composition and insignificant postmortal erosion. small pyrite granules frequntly occur in marls, which may indicate a more reducing environment (allison, 1990). however, these conditions were most probably present only close to the bottom. faunistic diversity with the dominant c o n g e r i a and l y m n o c a r d i u m genera in the upper parts of this facies might suggest slightly increased salinity to mesohaline (fig. 10) by the end of the pannonian, and this is supported by the occurrence of new bivalve genera (d i d a c n a , p a r a d a c n a , c a l a d a c n a ) and ostracod subgenera (l i n e o c y p r i s, t y p h l o c y p r e l l a, s i n e g u b i e l l a). congerian forms belong to the modioliformes and subglobosae groups, which live attached by a byssus to a soft substrate (andrusov, 1923) and are good indicators of calm and brackish water. 3.3. reconstruction of layered mechanisms the sarmatian clay and marls (facies a) were deposited in comparatively deeper and more protected, semi-closed areas (lagoons, estuaries). the insufficiency of considerable fluvial flows and smaller amounts of planktonic foraminifera indicate the isolation of the depositional system. the depth of the depositional system is determined by the high content of reductive layered components (pyrite, manganese, phosphate), low biogenic content and degree of skeletal fossilization and by the preservation of primary mm-lamination and the low granulometric composition (dodd & stanton, 1990). facies a sediments (“varvite”) were deposited from surface suspension flows and with frequent seasonal climate changes (fig. 7) by changing the thermal gradient (thermocline) of a stratified water column. light laminae were formed during periods of lower atmospheric temperatures, when the inflow of terrigenous material was decreased, while dark laminae were deposited during the increased inflow of siliciclastic and organic terrigenous material. a similar example was described by bottjer & savrda (1990). constant turbidity of the surface level and bottom currents, together with the probable vertical stratification of water salinity, had a selective influence on organic production (similar to the modern situation in black sea). characteristics of sarmatian depositional system continued to the early pannonian as indicated by continuous sedimentation. this is expressed by deposition of the “transitional layers” of facies ab, characterized by structural-petrographic properties of the older, underlying deposits. the fossil association of small, degenerated cardids and pulmonate gastropods indicate partial “life discontinuity” towards the older deposits, as the consequence of shallowing, restriction and desalinization of the marine environment (vrsaljko, 1997). limestone and marls of facies b were deposited in a shallow, “lake-pond” palaeoenvironment (fig. 8), without considerable influence of a land area. limestone beds were layered in the shallow littoral zone, and marls deposited from suspension were layered in slightly deeper lake areas (sublittoral), by combined physicochemical and biogenic processes. the basic model for the interpretation of the formation of these layers is a study by allen & collinson (1986). periodic and comparatively poor inflow of terrigenous material is indicated by cm-thick interlayers of fine-grained sand, which have the form of bands or lenses, with planar cross-lamination (?ripple marks). the discovery of numerous “seegrasswissenfauna” (pulmonate gastropods, small limnocardids and ostracods), which live on water grasses (“fossil reed” kranjec et al., 1973) as epibionts, determine the high degree of aeration and desalinization of the lacustrine area. frequent limonite granules indicate the oxidizing conditions of carbonate layering (allison, 1990). the gravels (c) and marls (d) were sedimented in a comparatively deeper palaeolacustrine environment (fig. 9). tectonic activity at the end of the early pannonian has been determined by boundary faults with considerable vertical movements in two directions (©iki∆ et al., 1979). coarse clastic sediments were transported from higher land areas to the depositional system by rivers and torrents, most probably forming a fan delta. in the upper half of the kostanjek-1 column, 20 geologia croatica 52/1 where the marl layers are dominant, three levels with gravel and sand were separated, so the instability, i.e. the occasional occurrence of significant rivers flows can be postulated. the discovery of a new limnocardid community and ostracods in the youngest part of the layers indicate the possible reestablishment of connections between these areas and the paratethys area, as is proved by stevanovi∆ (1985). 3.4. evolutionary series of the cardiidae family within the vertical sediment succession, lithological changes as well as faunistic changes have been detected, from the sarmatian up to the late pannonian. combined, sedimentological and palaeontological analysis allowed the definition of the formation, trends and characteristics of the layers. during the evolution of the depositional system (figs. 7-9) the permanent desalinization of the water became evident, particularly as shown by the cardiidae group of molluscs. at the end of badenian only some groups of organisms (sene© & papp, 1974) survived the salinity crisis, while certain cardid species “continued” into the sarmatian with considerable evolutionary changes. the change from mesohaline to polihaline conditions resulted in the cardid bivalves developing smaller and thinner shells with the reduction of teeth-hook apparatus. in the newly formed brackish sarmatian environment, a cardid form can be found, which has been defined by some authors as a separate c e r a s t o d e r m a subgenus (kojumdgieva, 1969), and by others as a c a r d i u m g e n u s (gorjanovi∆-kramberger, 1890). here, the results from the later, more current study have been adapted. the continuous salinity drop, which overlaps in the western and central paratethys areas with the period of the formation of the pannonian basin (lower part of the middle sarmatian), and its isolation from the eastern parts (stevanovi∆, 1985), resulted in an evolutionary surge in the cardid group. for the majority of spefig. 8 idealized depositional model for sedimentation of the lower pannonian carbonates. fig. 9 idealized depositional scenario allowing simultaneous deposition of coarse fluvial clastics and deepwater upper pannonian marls. fig. 7 idealized depositional model for sedimentation of the sarmatian clays. 21vrsaljko: the pannonian palaeoecology and biostratigraphy of molluscs from kostanjek... cies of sarmatian cardids the salinity drop has a disastrous influence. only a few species evolved and adapted to the new conditions. evolutionary changes are expressed by their smaller dimensions, longer and thinner shells, the increased number and occurrence of secondary ribs, almost entire reduction of cardinal teeth hooks, and probably altered skeleton mineralization. recently most authors separate and determine these pannonian forms as a separate l y m n o c a r d i u m g e n u s (stevanovi∆, 1957), which is also accepted in this paper. spatial isolation of the pannonian basin was the cause of the occurrence of the variability and endemism in many species. the multiple mutations provide evolutionary material for the occurrence of new limnocardid species in a comparatively short period of time. the formation of new species of the l y m n o c a r d i i n a e s u bfamily at the end of pannonian (p a r a d a c n a , d i d a c n a , c a l a d a c n a ) marks the evolutionary maximum of this group. this maximum may have two interpretations: 1) the settlement (expansion) of “finished species” from the eastern parts (dacian and euxinian basin), due to a reestablished connection with the unique paratethys area (stevanovi∆, 1985), and/or 2) a mixture of newly settled “immature eastern species” with domiciliary forms, and comparatively accelerated evolutionary change up to the level of creation of new genera, which is more probable. starting from the fact that all pannonian limnocardids (sensu lato ) are evolutionary derived from the sarmatian cardids (sensu lato), using morphological-functional scale analysis, and following the constructive morphological diagnostic characteristics (basch, 1990), their phylogenetic series were defined (fig. 10). phylogenetic relationships were produced according to the models of kolesnikov (1948) and kojumdgieva (1969), who divided the cardid group into four basic groups: obsoletiformes, inaequicostates, protractiformes and plicataeformes. the plicataeformes group is the most poorly represented in the pannonian strata of the kostanjek-1 column. not until the lower pannonian sediments is the lymnocardium plicataeformis species found, which is probabaly an evolutionary descendant of the sarmatian cardium (c e r a s t o d e r m a ) l a t i s u l c u m form. the new species is quite variable as indicated by the changeable number of ribs (13-15), that are sometimes decorated with pierce marks, and by the occurrence of weaker secondary ribs (3-4) in some samples. the protractiformes group has two representatives in the pannonian layers: lymnocardium spinosum which can be most frequently found in the zone of tranfig. 10 the phylogeny of the cardiidae family (according to basal diagnostic elements: number and type of ribs), and span of species occurrences in the sedimentary succession of the sarmatian and pannonian. 2 2 g eo lo g ia c ro at ic a 5 2 /1 i 23vrsaljko: the pannonian palaeoecology and biostratigraphy of molluscs from kostanjek... sitional layers (lower upper pannonian) and l y m n o cardium gorjanovici which has been found in the upper part of the upper pannonian marls. the former is an indirect descendant (between the original form and l . s p i n o s u m a transitional form should be defined) from the sarmatian cardium (c e r . ) l i t h o p o d o l i c u m s p e c i e s , and differs from it by the considerably increased number of ribs, and significantly smaller shell size and finally by strengthening of the back hook edge with small pierce marks. the latter l. g o r j a n o v i c i form is once again larger and distinguished by the occurrence of various rib types, from pointed to rounded. in the inaequicostates group, the early pannonian lymnocardium praeponticum developed from the original sarmatian cardium (c e r . ) g l e i c h e n b e r g e n s e f o r m , keeping the basic shell characteristics. later forms: caladacna ornata and paradacna syrmiense occured in the late pannonian along with significant changes in the number and type of ribs, and greater elongation. lymnocardium robici with apparent variability (changable relations between rib width and interribs parts) might be the transitional form among the majority of pannonian limnocardids (sensu lato). the most represented group is the obsoletiformes, in which the evolutionary changes from the original sarmatian cardids to the pannonian limnocardids, can be clearly followed. earlier pannonian forms (l y m n o cardium obsoletum protractum , l. fatioi and l. promul t i s t r i a t u m ) originated directly from older brackish forms (gorjanovi∆-kramberger, 1890), with insignificant morphometric differences. it is possible that l. cekusi, which generally appears in the middle of the sedimentary column, is the transitional form to the late pannonian didacna deserta and l. winkleri forms. gorjanovi∆-kramberger (1890) was the first to define the l. c e k u s i species in the lowest parts of pannonian marls of vrapëe. however the author was not aware of the biostratigraphic condensation phenomenon, which necessitates revision of the stratigraphic position of this species (vrsaljko, 1997). the evaluation of the comparative significance of every limnocardid species throughout geological history cannot be completely understood without study of the adaptive (natural selection) and morphogenetic (growth processes) factors, which is not complete in this case. however, on the basis of the established development series, and some specific mollusc index fosssils, it is possible to suggest biostratigraphic zoning in the sediments of the pannonian basin, which should be completed and tested by future research. 3.5. biozones accepting earlier research, especially papp (1951, 1953, 1956) and stevanovi∆ (1951, 1953, 1957, 1985), on the stratigraphy of pannonian basin, new solutions are proposed here (fig. 2, tables 2 and 5). in the kostanjek-1 geological column (fig. 2), rare samples of ervilia dissita and cardium (cerastoderma ) v i n d o b o n e n s e with a rare accessory foraminiferal community of miliolidae and elphidium group occur within the laminites (facies a), which collectively indicates zone “d” (sene© & papp, 1974), i.e. n15 zone, which is of the late sarmatian age (sensu stricto). lower pannonian marls and clays of facies ab contain ostracod samples, which represent an overture for the later explosion and divergence of species (hajektadesse, pers. comm.). in this lowest part of the pannonian there are also examples of small limnocardids. previous analysis of individual, characteristic mollusc species, resulted in the pannonian layers of broader areas (kranjec et al., 1973; ©iki∆ et al., 1978, 1979) being divided into two acrozones (lower r a d i x c r o a t i c a and the upper congeria banatica ), which are inadequate. treating the entire fossil mollusc community by the method of characteristic associations (uniqueness of identical community) produced more detailed results. therefore, in the entire pannonian succession of the kostanjek-1 column three zones and two subzones can be separated (table 2, fig. 2): subzone i (0-3 m thick): “poor zone of transitional layers” lymnocardium praeponticum acrozone. finelaminated clay and marl with rare samples of l. prae p o n t i c u m and small gastropods of h y d r o b i a and the v a l v a t a group. the lowest part of the early pannonian substage. zone ii (3-27 m thick): cenozone radix croatica lymnocardium plicataeformis gyraulus praeponticus . layered limestone and marl with frequent and numerous gastropods. examples of radix croatica , r. exten s a, gyraulus praeponticus , g. dubius and others, and bivalves of lymnocardium plicataeformis, l. c f . p r o multistriatum, l. praeponticum , l. obsoletum, congeria sp. ?nov. and other accessory forms, which entirely represent the early pannonian. subzone iii (27-35 m thick): “transitional layers” neodelminiella venusta lymnocardium cekusi c e n ozone. silty marl with rare gastropod community including neodelminiella venusta, radix kobelti, g y r a u l u s d u b i u s, undulotheca halavatsi and others. also bivalves of lymnocardium cekusi, l. spinosum, l. cf. robici, ?cerastoderma protracta , and other transitional species, determined (conditionally) as the middle pannonian. zone iv (35-65 m thick): congeria banatica lym nocardium gorjanovici gyraulus tenuistriatus c e n ozone. massive marl with abundant bivalve community: congeria banatica , c. m a r t o n f i i, c. z a h a l k a i, l y m n o table 5 list of molluscs from the kostanjek-1 column. 24 geologia croatica 52/1 table 6 list of ostracods from the kostanjek-1 column. cardium gorjanovici , l. cekusi, l. spinosum, caladacna o r n a t a and others. gastropods gyraulus tenuistriatus , orygoceras laevis , micromelania striata and other less important fossils also occur. lower and central part of the late pannonian substage. • 70 ... , ' 25vrsaljko: the pannonian palaeoecology and biostratigraphy of molluscs from kostanjek... zone v (65-83 m thick): congeria czjzeki lymno cardium winkleri gyraulus tenuistriatus c e n o z o n e . massive marl and clay with evolved bivalve community including congeria czjzeki, c. banatica , lymnocardium w i n k l e r i, l. cf. r o b i c i , paradacna syrmiense , d i d a c n a d e s e r t a , p i s i d i u m sp. also contains gastropods o r y g o ceras c f . b r u s i n a i , velutinopsis c f . p a n c i c i , g y r a u l u s t e n u i s t r i a t u s and others. uppermost part of the late pannonian substage. due to the specific development and comparatively narrow regional spreading of “so-called croatica layers” (jenko, 1944), this locality in podsused, among other possibilities, should serve as the stratotype for correlation in the western and central parts of the pannonian basin (holland, 1990). 4. conclusions 1) in the study area the formation of the pannonian basin as a separate palaeogeographic province, which partly overlaps with the isolation of the western and central paratethys from the eastern parts during the middle sarmatian (sensu lato), is expressed in the layering of fluvial-lacustrine pannonian sediments with a unique endemic mollusc and ostracod fauna which have oligohaline characteristics. 2) the end of the sarmatian (sensu stricto) sedimentation cycle in the study area is manifested as a continuity of sedimentation into the pannonian, due to the significant desalinization of the water. 3) the salinity drop at the sarmatian-pannonian boundary is manifested by the disappearance of most sarmatian organisms (especially gastropods and foraminifera), and the occurrence of new pannonian mollusc and ostracod forms. it can be best followed through the evolutionary changes of the c a r d i i d a e family. 4) altered water chemistry in the pannonian is reflected by changes in the style of sedimentation, and can be followed through geochemical parameters such as carbonate content and content of trace elements (especially strontium and manganese). 5) the great variability and weak diversity of taxonomic structures of organisms in the early pannonian substage is the consequence of basin isolation, and is manifested by the endemism of most fossil groups. 6) gravel lenses of fluvial origin (fan delta system), situated in the upper pannonian deep-water marls, are the result of synsedimentary tectonics, which reflected regional tectonic movements. 7) taxonomic diversity of the fossil community of the late pannonian is the consequence of optimum environmental conditions, and relates to the evolutionary maximum of most lacustrine organisms, and was probably the consequence of the introduction of new species from the back-carpathian area. 8) layering of the sarmatian laminites in reduced conditions with high contents of manganese and pyrite (comparable with the recent situation in the black sea), together with high periodic organic production, could indicate their potential as source rocks. 9) phylogenetic analysis of the c a r d i i d a e family should be complememented with the analysis of adaptive and morphogenetic factors, to improve the qualitative estimation of their evolutionary and stratigraphic significance. acknowledgements this study resulted from a project “facies and physical characters of neogene carbonate sediments”, which was conducted under the supervision of mato pikija to whom i am sincerely thankful for his valuable instruction and professional advice. i thank my colleagues for numerous analytical data, especialy specialists from the institute of geology: valentina hajek-tadesse for the definition of numerous ostracod forms, slobodan miko for trace elements analyses, vlasta juri©i∆mitrovi∆ for major elements analyses, and æeljka glovacki-jernej for petrographic analyses. i wish to thank miroslav kladni»ki who prepared figures and tables. 5. references allen, p.a. & collinson, j.d. (1986): lakes.in: reading, h.g. (ed.): sedimentary environments and facies. 2nd ed., blackwell sci. publ., 69-73, oxford. allison, p.a. (1990): nodules and platenkalks.in: briggs, d.e.g. & crowther, p.r. (eds.): palaeobiology. blackwell sci. publ., 250-253, oxford. andrusov, n. (1917): pontiëeskij jarus.geol. rossii, 42/2, 1-41, petrograd. andrusov, n. (1923): apseronskij jarus.mem. col. geol., 110, 1-206, st. petersburg. basch, o. (1990): cardiidae (mollusca, lamellibranchiata) pontskog kata u hrvatskoj.paleont. jugosl., 39, 1-158, zagreb. bottjer, d.j. & savrda, c.e. (1990): oxygen levels from biofacies and trace fossils.in: briggs, d.e.g. & crowther, p.r. (eds.): palaeobiology. blackwell sci. publ., 408-410, oxford. brett, c.e. & speyer, s.e. (1990): taphofacies.in: briggs, d.e.g. & crowther, p.r. (eds.): palaeobiology. blackwell sci. publ., 258-263, oxford. 26 geologia croatica 52/1 brusina, s. (1897): gragja za neogensku malakoloπku faunu dalmacije, hrvatske i slavonije uz neke vrste iz bosne i hercegovine i srbije.rad jugosl. akad. znan. i umjet., 18, 1-43, zagreb. dodd, j.r. & stanton, r.j. (1990): palaeoecology, concepts and aplications.a wiley-intersc. publ., new york, 502 p. gorjanovi∆-kramberger, d. (1890): die präpontischen bildungen des agramer gebirges.glasnik hrv. narav. druπtva, 5, 151-164, zagreb. holland, c.h. (1990): biostratigraphic units and the stratotype golden spike concept.in: briggs, d.e.g. & croether, p.r. (eds.): palaeobiology. blackwell sci. publ., 461-465, oxford. hudson, j.d. (1990): salinity from faunal analysis and geochemistry.in: briggs, d.e.g. & crowther, p.r. (eds.): palaeobiology. blackwell sci. publ., 406-408, oxford. jenko, k. (1944): stratigrafski i tektonski snoπaj pliocena juænog poboëja poæeπke gore i kasonja brda.vjestnik hrv. dræav. geol. zavoda i hrv. dræav. geol. muzeja, 2/3, 89-159, zagreb. kojumdgieva, e. (1969): fossilite na blgaria sarmat.blg. akad. nauk., 8, 1-133, sofia. kolesnikov, w.p. (1948): die sarmatische stufe.die strat. der sssr, 12, 1-242, moskva. kranjec, v., hernitz, z. & prelogovi∆, e. (1973): prilog poznavanju mlaih tercijarnih naslaga medvednice (sz hrvatska).geol. vjesnik, 25, 65-99. kranz, j.r. (1976): strontium ein fazies-diagenese-indikator im oberen wettersteinkalk (mitteltrias) der ostalpen.geol. rdsch., 65, 593-615, stuttgart. moos, a. (1944): neue funde von limnaeiden, insbesondere von valenciennesiden in pannon kroatiens.vjestnik hrv. dræav. geol. zavoda i hrv. dræav. geol. muzeja, 2/3, 341-391, zagreb. nagymarosy, a. & müller, p. (1988): some aspects of neogene biostratigraphy in the pannonian basin.in: royden, l.h. & horvath, f. (eds.): the pannonian basin, a study in basin evolution. amer. assoc. petr. geol., mem. spec., 45, 69-77, budapest and tulsa. oæegovi∆, f. (1944): prilog geologiji mlaeg tercijara na temelju podataka iz novijih buπotina u hrvatskoj.vjestnik hrv. dræav. geol. zavoda i hrv. dræav. geol. muzeja, 2/3, 391-473, zagreb. papp, a. (1951): das pannonian des wiener beckens.mitt. geol. ges., 39-41, 99-193, wien. papp, a. (1953): die molluskenfauna des pannon im wiener becken.mitt. geol. ges., 44, 85-222, wien. papp, a. (1956): paläontologische beobachtungen im pannon von podsused bei zagreb (kroatien).geol. vjesnik, 8-9, 67-81. pirson, j.s. (1985): geologic well-log analysis.gulf publ. comp., houston, 71 p. pokorny, v. (1946): microstratigraphie pannonu mezi hodonienem a mikulcicemi.razpravi ceske akad. ved., 54, 23-41, praha. sene©, j. & papp, a. (1974): grundzuge der entwicklung der fauna und die biozonen im sarmatien s. str. der zentralen paratethys.in: brestenska, e. (ed.): chronostratigraphie und neostratotypen sarmatien. verlag slowak. akad. wiss, 4, 41-44, bratislava. soka», a. (1972): panonska i pontska fauna ostrakoda zagrebaëke gore.paleont. jugosl., 11, 1-140, zagreb. soka», a. (1985): das pannonien in kroatien.in: papp, a., jambor, a. & steininger, f.f. (eds.): chronostratigraphie und neostratotypen pannonien. ung. geol. anst., 89-95, budapest. steininger, f.f., rabeder, g. & roegl, f. (1985): land mammal distribution in the mediterranean neogene: a consequence of geokinematic and climatic events.in: stanley & wezel (eds.): geological evolution of the mediterranean basin. springer-verlag, 559-571, new york. stevanovi∆, p. (1951): donji pliocen srbije i susednih oblasti.srb. akad. nauka i umet., 187, 1-286, beograd. stevanovi∆, p. (1953): nomenklatura tercijarnih slojeva, u prvom redu domaêih neogenih terena.i. savjet. geol. fnrj u zagrebu, hrv. geol. druπtvo, 121-143, zagreb. stevanovi∆, p. (1957): pannon und pont im nordlichen bosnien bedeutung ihrer studien für die lösung der faziesprobleme und horizontierung der congerienschichten im pannonischen becken.ii. kongres geol. jugosl., 155-176, sarajevo. stevanovi∆, p. (1985): diskussion der unterstufen slavonien und serbien.in: papp, a., jambor, a. & steininger, f.f. (eds.): chronostratigraphie und neostratotypen pannonien. ung. geol. anst., 82-85, budapest. ©iki∆, k., basch, o. & ©imuni∆, a. (1978): osnovna geoloπka karta sfrj 1:100000. list zagreb l33-80.geol. zavod zagreb (1972), savez. geol. zavod beograd. ©iki∆, k., basch, o. & ©imuni∆, a. (1979): osnovna geoloπka karta sfrj 1:100000. tumaë za list zagreb l33-80 (geology of zagreb sheet).geol. zavod zagreb (1972), savez. geol. zavod beograd, 81 p. 27vrsaljko: the pannonian palaeoecology and biostratigraphy of molluscs from kostanjek... vrsaljko, d., pikija, m., ©iki∆, k. & glovacki-jernej, æ. (1995): sarmatske i panonske naslage u tupinolomu kostanjek.in: ©iki∆, k. (ed.): geoloπki vodië medvednice, 56-60, zagreb. vrsaljko, d. (1997): stratigrafija naslaga panona jugozapadnog dijela medvednice.unpublished m.sc. thesis, university of zagreb, 80 p. manuscript received december 4, 1998. revised manuscript accepted may 28, 1999. 28 geologia croatica 52/1 geol. croat. 50/1 79 88 5 figs. 3 tabs. zagreb 1997 frequency distribution curves as an indicator of evolutionary trends in geomorphological systems: a case study from the northwestern part of hrvatsko zagorje (croatia) zoran peh key words: geomorphological systems, 'i'hc rmocly­ nami cs or nollcquilibrium systems, frequency dis­ tribut ion curves, horizontal dissection, vertical dis­ sectio n, hypsoll1ctric ij1lcgral, drainage densit y, slope, erosional levels, hrva tsko zagorje, croat ia. abstract frequency (lislribulion curves can be indicative of the dynamics and cvo!liliol1<ity development of gcomorpho logic.tl systems. normal­ ly distriblllcd geomorphological data arc a reliable indicator of th e equi librium tluctualions prevalent within such systems. thi s occurs, for example, when i\ delicate balance is established between varioll s lypes of landform s and geomorphological proces ses . landforms illat ex ist in thi s geomorphological steady state can be properly ca ll ed "equilibrium" structures . they show no pcrmanen t trends of either growth or destruction. on the contrary, a positively skewed frequency distribution curvc indicutes a type of non-equilibrium cond iti ons and iloll -line:lr rel:ltionships w ithi n geomorphological systems, which illay be the resu lt of major cx ternal energy inputs (particu larly from tcc tonic uplift ). thi s. in turn. gi ves rise to new and more complex higher-order landfonns. these represent structures of growth . or evo­ lut ion. alle rnati vely, a negati vely skewed freq uency distri bution curve, also be ing a consequence of non-equilibrium conditions, ind i­ cates a lack o f free energy in ihe system. which induces destflletion of [he existing landforms. such landforms represent struclllres of degen­ eration. the rlu vial landscape i n the northwestern pari of hrvatsko zagorj e, portrayed in terms of an open system, has been used as the geomorphologica l framework for this study, the primmy purpose o f which was (0 apply frequency di~tribution curves in the interprelll ti oll of the processes influenc ing the creation and destructi on of the 1'\i1d­ scilpe. i [ori zo lltal and vertical dissection, slopc and other morphomct­ ric clwracteris tics rcnecllhc spcc ific dynamics of the geomorphologi­ cal processes, which relate a variety of landforms to th eir geologic framework and climate in thc study arca. 1. introduction a diligent search for solid proof of how the proccss­ es shaping the face of our planet actually work, resulted in the acceptance and application of new concepts in geo logy. these originate from the domain of funda ­ mentnl natural sc iences, particularly mathematics and phys ics . however, despite the fact that geology, nnci geomorphology in particular, has taken a great leap in tnstitutc of geology. sachsova 2, hr-l 0000 zagreb, croatia . the last few decad es owing to newly promoted ideas, many questions, especially those concerning the prob­ lems of evolution of geomorphological sys tcms, remain unanswered. very often, emphasis is placed on the fact tha i all natura l systems, including geomorpho logical ones, are too complex for analy tical treatment beyond a rout ine search for the empirical relati ons hips among assessed data (patee, 1973; karcz. 1980). never­ theless, many recent ideas may be directly applied, par­ ticularly with regard to the problem of struc tural stabili­ ty and related fluctuation phenomcna (osci llations of system parameters), that are considered to be the main cause of pcrmanent and irrevers ibl e change in natural sys tems. stability and cquilibrium , re fl ected in the geo­ morphological steady-state concept, present the general­ ly accept cd axioms around which the analysis of vari­ ous geological and geomorphological systems has revolved in the past few decades (ki\rcz, 1980). one should emphasize. though, thai evolution of the natura l systems, including landscapes. docs not proceed via the equilibrium condi tions that prescribe ihe stable llux of matter and cnergy. on the contrary, evolution is induced by a shock occurring as a system's response to strong external impul ses. evolutionary processes, trig­ gered as the system reaches the far-fromequilibrium, non-linear regime, eventually inc rease its structural comp lexity (nicolls & prigogine, 1977; pri­ goglne. 1978; karcz, 1980; prigogine & stengers. 1985 , and others) . in geomorphological sys tems these changes have bee n exemplified by drainage network expansion, ihe grow ing intens ity of vertical dissection and ihe general appearance o f ne w, hi gher-order features in a landscape. a re liable indica­ lor of such changes a re frequency distribution curvcs of ihe system parameters. their analysis, therefore, can be of great imporlanee in understandi ng geomorphological, and geological processes in a givcn area. the aim of thi s investi ga ti o n is to pl ace greater emphasis on thc potential applicat ion of frequency di s­ tribution curves in the analys is and appraisal or various geomorphic phenomena and the ir dynamics in a fluvial landscape (the northwestern part of i-irvat sko zagorje). previous studies in this area, carricd out to exam ine the dynamic interplay of various fluvial landform s (pel-i, 1990), as wei! as to e lucidate the re lationship between the driving forc es and resistant geological framework '0 slovenia croatia fig. 1 location map of the study area. (peh, 1992), dealt with a single li"agment on a hierar­ chical scale of system relationships. conclusions drawn from this research have adequately described the spatial changes caused by climate and tectonic movements during the particular geologic period defined by the rel­ ative age (order) of drainage basins. however, exclu­ sive study of the spatial relationships among geomor­ phological parameters thus defined, has not established temporal trends of landscape evolution with any degree of certainty. only after several adjacent, hierarchically ordered geomorphological systems had been analyzed toget her , could a more explicit refe rence to the time component involved in the investigation of the dynam­ ics of geomorphologic processes be made (peh, 1994). it seems possible that the probability distribution curve, illustrating a specific geomorphologic process , can be exceptionally helpful as a very simple indicator of evo­ lution. therefore, when applied with reference to a par­ ticular geolog ical framework, this method can supply the necessary information about the origin of the land­ scape and its destruction. the primary objective of this study is to highlight utilization of the frequency distribution curves, with examples of how the drainage network, slopes and oth­ er geomorphic parameters develop within hierarchically de fin ed geomorphological systems in the nw part of hrva tsko zagorje (fig. i). however, the parameters lised refer to the recent period in development of the geologia croatic<l 50/1 study area, which is defined by the relative age of the drainage basins ranging from the fifth to the third order. data used in the study derive from the mathematically treated morphometric and geological variables. they are presented in the form of deviations (fluctuations) from standardized means and displayed in appropriate tables and diagrams (peh, 1994). 2. thermodynamic background earlier investigations of the fluvial geomorphologi­ cal phenomena, were mostly founded on the concept of energy distribution on the surface of our planet being both stable and uniform in time and space. the steady­ state approach assumcd that system parameters (variety of landforms presented mainly in the form of morpho­ metric data) uniformly oscillate around an equilibrium position as they adjust (with minimum internal change) to external forces, allowing a system as unity to remain in a stable equilibrium (chorley, 1962; leopold & langbein, 1962; howard, 1965; scheideg­ ger & langbein, 1966; king, 1967 and others). the fact that permanent changes of morphometric para­ meters do not allow the system to reach stability, even during the long term (schumm & lichty , 1965; chorley & kennedy, 1971; schumm, 1973; bull, 1975, and others) had largely been ignored while, at best, a number of temporary steady states can be form ed which represent transient phases in the land­ scape development. the basic idea underlying more recent geomorphological research (coates & vitek, 1980; karcz, 1980; ritter, 1988) is founded on the premise that only a particular iype of d isequilibrium, driven by high iluctuations within the geomorphological system, can generate new landforms. in the process of adjustment, the mechanisms of self-regulation and self-stabilizing negative feedback formulated in prigogine's rule of minimum entropy production (prigogine, 1978), and the lc chatelier­ brown principle of linear reaction, play the key role . the stability zone in the neighbourhood of equilibrium is usually called the thermodynamic branch (glans­ dorff & prigogine, 1971; nicolls & pri­ gogine, 1977). this is a domain of a linear, station­ ary regime , where the probability distributions of the system components obey the gaussian law (nicolls & prigogine, 1977; keizer, 1987). landforms described in terms of different morphometric variables do not greatly deviate from the average, which is valid for a system as a whole. their main feature, defined in the language of thermodynamics, is aptly expressed in the term of "equilibrium structures". however, strong external energy input s can upset a system and drive it completely out of equilibrium. these generate fluc tuations with sufficiently high potential energy 10 trigger irreversible loss of structural stability, which manifests itself largely through the mechanism of positive feedback. instead of being pch: frequcncy dislribution curves as an indic:lior of evolutionary trends in geomorphological systems ... 81 a 11 o +11 b types of distribution curves the above considerations lead to the conclusion that the instability of landforms (s tructural instability when cons idered in a the rmodynamic sense) is caused by great fluc tuations which serve as the basic evolutionary impulse in geomo rpholog ical systems. in this respect, insight into laws govern ing the behaviour o f the proba~ bility di stribution of flu ctuations is of the g reatest importance for the study of their developmental charac~ teristics. in a system which is characterized by struclur~ al stability within the limit s of the thermodynamic branch, flu ctuations will be dist inguished by a qu ite dif~ rerent pro bability dis tribu tion with regard to another system wi th an unstable response in the neighbourhood of, or beyond the thermodynamic threshold. in the first case , when a systcm is dominated by an eq uilibrium reg ime, the frequency di stribution of jluctuati ons w ill ex hibit a normal (gauss ian) shape of probability eurve (fig. 2a). tn the latter, however, when the balance of a system is upset, and relationships approach the non~lin~ car domain, the frequency distribution of flu ctuations will assume positive skewness (fig. 2b). thi s type of asy mmetry is a direct effect of the presence of a very small number of ouctuations carrying a hi gh energy potential. thcy have the leas t probability of occurrence -6 c owing to the second law of thermodynamics which prc~ sc ribes that equil ibri um in the neighbourhood o f the mean system trajectory exemplifies the most probable system state. the grcaler the magnitude of fluctuations (that is, their potential energy), the smaller the probabil~ it y of the ir occ urrence, which accounts for a posi ti ve fig. 2 typical rrobabilily distri buti on cllrve of nu cl uatiolls: a) gauss ian normal probability di s tri but ion curv c; b) pos itively skewed probabilit y distribution c urv e: c) negative ly skewed probability distribution curvc. on abscissa cr stands ror the mea­ surc or nucluation.~ . damped, such flu ctuations arc amplified, leading a sys~ tem into the domain o f a qualitatively diffcrent regime of processes, with a dist incti ve ly different development nature. changes at the boundaries of the thel11lodynam ~ ic branch, which cause the onset of the loss of stability, are charactcrized by the occurrence of n ojl~ lillear rela~ tionshi ps among system parameters, by the shi ft to a non~gaussian , skewed frequency distribution of f1uctu~ at iolls (d1m entberg, 1989). landforms o riginating in such thcrmodynamic cond itions depart considerably from the mean which is charactcristic for a system as a whole. their main properties can be conveniently summarized as being the epitome of "diss ipative structures" owing to the strong and continuous dissipation of encr~ gy th ro ughout the geomorpholog ical realm (karcz, 1980). they are new, self~organi zed landforms which orig inatcd as a resu lt of " order through flu ct uations" (g lans do rff & prigogi ne, 1971 ; nicolls & prigogine, 1977; prigogine & stengers , 1985; knori ng & dec, 1989). skew of their distribution becoming more and morc pronounced (dimentberg , 1989). there is another type or geomorphological process which is also characteri zed by a skewed frequency dis­ tr ibut ion curve. tn this case, q uite a different set of processes is observed, wh ich are dist inguished by a lack of energy. thi s sta te is charac terized by a re la tively sm all number of flu c tuations with exceptiona ll y high negative amp litudes. general ly, this is the case when many of the flu ct uati ons are clustered at or nea r an upper limit of some natural process (koch & li nk, 197 1), as di stinguished from the system processes which lend to maintai n the structural stability of ex i s t ~ ing steady states (normal distribution of flu c tua ti ons), or processes that g ive rise to new, more organi zed structures (positively s kewed di stributi on of nue tua~ tions). the emphasis here is on the processes of gradual decay of preexisting structures which are surrounded by condition s of decreas in g pot ential ene rgy, necessary ei ther to maintain the stationary state or to spur evo l u~ ti onary change, thus produc ing a negati vely skewed d istribution. 3. a case study geomorphol og ical processes arc di stinguished not only by their ample di vers ity, but also by their specific 82 geologia cro:nic<l 50/1 min max skewness kurtosis ksks+ type of distribution processes concerning drainage network horizontal dissection -1.49 4.79 1.42 2.95 0.09 0.11 drainage density -2.84 2.90 -0.30 0.42 -0.06 0 .04 => + processes concerning vertical differentiation vertical dissection -1.55 3.11 0.75 1.60 0.05 0.08 + slope -1.78 2.15 -0.11 -0.99 0.08 0 .07 <= erosional levels hypsometric integral -3.00 3.64 0 .54 1.96 0.06 0.09 + table i distribution of l1uctualions in the investigated geomorphological system or the 3'" order (n= [80). critical values of k-$ lest ror 180 objects: ks+. ks= 0.0909 (0.=0.05): ~ positive skewness; ¢:::: negative skewness: + nonnal di stri butioll. spatial dynamics. the system dynam ics produce a who le array o f landforms, particularl y in the fluvial landscape. inves ti gations have shown (e .g. stra1-iler, 1952; melton , 1957; brus h, 196 1; car­ son, 1971 ; ritter , 1978; hart, 1986, and others) that the nature or geomorphological processes is affect­ ed no t on ly by the magni tude, durat ion and direction of driving forces, but equally, if not to a grcater extent, by the resist ive forces of the underlying geological frame­ work. in the mutual interaction o f the driving and res is­ tant forces, energy and material entering a sys tem is iransfeneel c ilhcr th to ugh spec ifi c composil c lanel­ forms, or landscape subsystems, which sim ultaneously undergo different stages of development. the study of the relat io nship between typi ca l geomorphological processes and their respective landforms in the nw part of i-lrva tsko zagorje (pel-i, 1994), has demonstrated tha t a geomorphological system, observed as a structur­ al unity over certain period of time, can, if only tem­ porari ly, ex ist in a state of balance with these processes. nevertheless, it s sepa rate part s, or subsyste ms, can ex hibit diffe rent stages of non-equilibrium state, the ultimate effect of wh ich would either be evol uti onary growth or degeneration. tectonism and lithological faetors are of extraordinary significance owing to their role as regulatory agents moderating the influence of exter­ nal factors, as they tend to absorb the effects of external disturbance (driv ing forces, particularly tectonism) and to cstablish a steady state between form and processes (chorley & kennedy, 197 1). the analysis of geomorphological sys tems of differ­ ent hierarchical levels (ranked aner the order or relati ve age of the main valleys) in the nw part o f hrvatsko zagorje (fig. i) shows that the study area is composed of severa l very homogeneou s landscape units, or sub­ systems, being quite distinctive on the local and reg ion­ a l scales of system relat ionships. these subsystems comprise: horizontal dissection, drainage density, vert i­ cal dissection, slope, erosional levels and the hypsomet­ ric integra l. they deve lop as a result of two basic types of land forming processes the processes of horizontal and ve rti ca l differen ti ation. appa rent var iat ions ca n arise frolll differences in magnitude involving the spa­ tial and temporal sca les on which the relationships in the geomorphological systems o f thi rd, fourth and fi fth order arc observed (peh, 1994). it is logical, therefore, to expect the nature of flu ctuations, lypical for particu­ lar subsystems, to depend on both the type of geomormin max skewness kurtosis ksks+ type of distribution horizontal dissection drainage density vertical dissection slope erosional levels hypsometric integral processes concerning drainage network -1.30 4.30 1.41 2.50 0. 11 processes concerning vertical differentiation -1.58 2.99 1.03 0.94 0.06 -2.37 1.75 -0.46 -0.38 0.10 -2.11 3.21 0.38 0.53 0.04 -1.94 4.10 1.06 3.56 0.04 0.16 0. 10 0.05 0.05 0.05 = => <= + + ta ble 2 distribut ion of fluctuat ions in the investigated geomorphological system of the 4th order (n= 160). critical values of k-s [cst for t 60 objects: ks+, ks= 0.0964 (<<=0.05): => posi ti ve skew ness: ¢::: negative skewness; + normal dis tribution. pch: fn."<llicncy di\l ribluioil curvcs;ls an indic:uor of evolutionary trends in cicomolphologico'll systems ... 83 min max skewness kurtosis ksks+ type of distribution processes concerning drainage network horizontal dissection -1.29 2.74 0.61 -0.50 0.10 0.13 => drainage density -2.72 2.99 0.15 0.91 0.06 0.08 + processes concerning vertical differentiation vertical dissection -1 .68 2.83 1.21 1.78 0.06 0.13 => slope -2.70 1.55 -1.19 1.57 0.13 0.08 <= erosional levels -3.55 1.90 -0.99 2.73 0.13 0.07 <= hypsometric integral -1.97 2.36 -0.32 0.20 0.08 0.05 + table 3 di .~ tribu l ion of fluctua tions in thc invc\tigalcd gcomorphological systc m of thc 51h order (n= i02). crit ical values of k-s lest fo r 102 objec ts: ks+, ks= 0. 1208 (u=o.05); ~ po.~ iti vc skewness; <= negative skewness: + norma! distribution. phologie process and thc scale inferred. if the distribu­ tional characteristics of fluctuation s arc to be properly stud ied , it is necessary to tcst the normality o r their fre­ quency dist ri bution wi th respect to each spec ifi c sub­ system (tab les i, 2 and 3). thi s norm ality tes t can allow conclusions to be made about the dynamics of the most promin ent geo morphological process . di stribu ­ tional c haracte ri sti cs o/" nuctuations can be tes ted by nonparam et ri c stati stical tests incl uding the kol ­ mogorov-sm irnov (ks) tcst where the c ri ti cal values (ksk) can be take n from the appropriate tables (e.g. davis, 1986). the procedu re of how the frequency distributions compare to a normal eurve is shown in tables 1-3, for each separately investi gated geomorphologic system. ana lys is of frequ ency distributions y ield s some very sign ificant result s ror the interpretati on o f the develop­ ment of the in ves ti gated geomorpholog ical sys tems. jt is obvious from tabl es 1-3 that the indi vidual subsys­ tems have follo wed different paths of deve lopmen t in the various geomorphological sys tems. morover, pro­ ceeding [rom lower 10 highcr lcvel rela ti onsh ips, a reg­ ular transformation of the shape or the dis tribution curve is apparent. thi s change manifes ts it se lf by a decrcase of potential energy cont ai ned in the fluctua­ tions, which cause a shift toward the sinistral, negative skewness w ith regard 10 spec ific geomorpholog ical processes. the faclo rs governing the mig ra tion of the mean system state trajectory (x:::: 0) toward the negative values (the probability oc the appea rance of negative flu ctuation s dec reases) can be numerous, but for the most part they ar ise from the effect o f seria l autocorre­ lation which becomes conspicuous as the higher-order geomorphological sys tems increase their structural complex ity (chorley & kennedy , 1971). name­ ly, int rica te and mutua lly perplexed re laxa tion pat hs, paved by serial autocorrelation due to the presence of the same morphornetri c variables, especial ly in the sys­ tcms of a higher rank, can considerably damp the effect of individual inputs o f ex ternal forces causing their activi ty to fa ll under some significant energy threshold (cii orley & kenne dy , 197 1). in addition, it illust be emphasized that the increase or a system rank (both enl argement of the phase space and expans ion o f it s physical borders) unavoidably leads a system to a state or hi gher entropy (wood & fr aser , 1977). thus, one ca n log ically ex pec t a system of the fifth -order drai nage basins (0 have hi gher entropy with respect to one o r the fourth -order, and the laller with respect to the one o r the third-order. exami nation of tables 1-3 and figs. 3-5 reveals that only the processes concern ing the development o r hori­ zontal di ssection cause da ta to assume a marked ly posi­ tive skew of distribution, irrespective or the hierarchical o rder under considerat ion. such a trend can be ex plained by the continuolls reorganization or the sub­ system of horizontal dissecti on which manifests it self at all hi e rarch ica l leve ls . when a drainage basin with expanding drainage ne twork of a g ivcn order li exceeds some lim iti ng size, there is a jump in the reorganization o f dra inage texture. th is produces a new drainage basi n or higher order u+1 (chorley & kennedy, 197 1). in accordance with the earli er cons ideration about sta­ bility, the new drainage basin of order u+l ex hi bits the features or dissipative structures wh ich are di stin ctly dirferent in re lation to the rest of the drainage basins of order u to wh ich it prev ious ly belonged. ;\ positi vely skewed frequency distribution curve (a lso histogram of iluctuati ons), which is indicative of the processes con­ cerning development of horizontal dissection , serves as a s ure indicator of the drai nage network evo lution in loca l (third-order drai nage bas in system), and reg ional (fifth -order drainage basin system) boundari es or sys­ tem re la tions hips. 11 is a lso character isti c of th e hi gh energy potent ial of the c li matic ractor (insol ati on, pre­ cipitation) in the study area, which operates approx i­ mately wi th the same intensity, regard less of the space­ time sca le defined by the hi erarchical order of the inves ti ga ted geomorphological system (fig. 3). 'rhe processes of vertical dissection are also di stin ­ gui shed by an expressly positively skewed distribution, wit h the exception of the thirel -oreler drainage bas in sys100 80 m z ~ 60 .! .. " :3 ~ ~ 0 40 '" w on " => 20 z 0 -3 -2 -1 0 100 80 . ---. m z ~ => 60 ~ ~ ~ ~ is 40 '" w on " => 20 z 0 -2 -1 0 100 • horizontal dissection l' 00dffi _ expe<;ted normal 2 3 5 ... horizontal dissection 4'" order ......... ~. _ expected normal 2 3 4 gcolo~ia croatica 5011 a 6 b 5 80 , ...... horizontal dissection ; .. m z 511 order ! 60 ~ ~ c ~ 40 0 '" w on _ oxpected normal " => 20 z 0 -2 -1 0 2 tem, where the subsystem of vertical dissection is found to be in stable equilibrium. thi s stability, irrespecti ve of the s lightly prominent positive asymmetly of the fre­ quency disiribu tion curves (table i), can be ex plained as a resul t of the compl ex response to external vari ­ ables. the characte ri sti c properties of vertical di ssec­ tion such as, for instance, the third-order drainage basin rclicf, arc combined wit h other altitudinal aspects of drainage basins valley-side slope, for example which inc reases the multiplicity of possib le linkages among variables. thi s allows many alternatives for potential adjustments among the landscape properties. additional relaxation paths occur so that a stationary state can be achieved relatively easily and quickly, even under great fig. 3 frequency distribution histogram of fluc3 tuations for the horizontal dissection, 3_5 '11 order, in lhe area of inve.~t igation. variations in the external regime incruding both endoge­ netic and exogenelic forces (c horley & ken­ nedy , 197 1), in the fourlh and firth-order drainage basins (tables 2 and 3), where the ve rlical dissection is dominantl y characterized by the hi ghest point on a watershed , and the total re li ef ins id e the basin (peh, 1990, 1992), such a possibility is considerably reduced. on thi s account the subsystem of vertica l dissection, as ari integral part of the fourthand fifth -order drainage basin system, adjusts to externa l impulses through the reorganization of its structural properties, and develop­ ment of dissipative structures in the zones where the structural stability has been irreversibly lost. since hori­ zo ntal and verti cal di ssec tion represent the domi nant peh: frequency dimributioil curves as an indicator of evo]utiollmy trends in geomolvhological systcms ... 85 100 hypsometric integral 80 w z 0 ~ 60 () " ~ ~ a ~ 0 40 "' w rn " oj 20 z 0 -4 -3 -2 -1 0 2 3 4 5 100 80 w hypsometric integral z 0 ~ oj 60 r () oj ~ ~ ~ 0 40 "' w rn " " 20 z 0 -3 100 80 w z 0 ~ " 60 () '3 ~ ~ 0 40 "' w rn " oj 20 z 0 -3 -2 -1 0 _ expectod nonnul _ "q><>ctoo normal 2 3 hypsometric integral 5th oroer geomorphological processes in the landscape of the study area, it is logical to assume that they will mostly reflect the evolutionary trends of the obscrved geomor­ phological systems. another group of geomorphological processes is distinguished by a normal frequency distribution curve of lluctuations, indicating structural stabilit y of the per­ taining subsystems, which is a consequence of their ability to maintain thei r structural attributes in the exist­ ing regime of external forces. such is the case of the subsystem of hypsometric integral (fig. 4) and the sub­ system of drainage density being integral parts of the fourthand fifth -order drainage basin systems. system componenls fluctuate within the limits of the them10dyb 5 c fig. 4 frcquency distribution hislogram of iluc3 luations for the hypsometr ic integral, 3_5'1> order, in the area of investigation. namic branch, sustaining the existing stat ionary state. in other words, potential energy carried by the fluctuations is neithcr too high to spur cvolutionary changes, nor too low to bring about degeneration of the present struc­ tures. the normal frequency distribution curve of l1uc­ tllations in the subsystem of drainage density supports the general concensus of opinion that drainage density in its present extent retlects a balance between the input and output of the hydrological cycle. its pattem disclos­ es a number of mutual adjustments providing for the maximum and most efficient surface runoff in the drainage basin (chorley & kennedy, 1971)_ conversely, the subsystem of the hypsometric integral (fig. 4) reflects equilibrium tendencies in the processes x6 ' 00 slope 80 3'11 order ~ z 0 ~ co 60 ~ 0 => ~ ~ ~ 0 40 ~ w rn " => 20 z 0 -3 -2 -1 0 100 slope 80 4lt1 order ~ z 0 ~ => 60 ~ u co ~ ~ ~ 0 40 ~ _ ~ednoml"l w rn " => 20 z 0 -3 -2 -, 0 ' 00 80 slope ~ z 5th order 0 ~ co 60 ~ 0 3 ~ ~ 0 40 ~ w rn _ expected normal " '" 20 z 0 -4 -2 of denudation, erosion, transportation and aggradation. in lower-order drainage basins the balance is es tab­ lished owing to the negative feedback between total relief and hypsometric integral (that is, among morpho­ metric propert ies only). in the higher-order drainage basins lithology plays the role of moderator in the process of mutual adjustment of the two morphometr ic variables channel gradient and valley-side slope (peh, 1992)_ processes involved in shaping the slope subsystem (fig. 5) and the subsystem of erosional levels afe distin­ gui shed by the progressive modification of the frequen­ cy distribution curve which shifts [rom normality towards negative skeweness as the order increases. the 2 geologia cromica 5011 a b 2 c fig. 5 frequency distribulion histogram of tluc2 illations for the slope, 3_5'10 order, in the area of investigation. slope subsystem in the third-order drainage basin sys­ tem is characterized by the normal distribution of fluc­ tuations. in the fou rthand fifth-order drainage basin system the distribution is more negatively skewed (fig. 5). the subsystem of erosional levels, which dissociates from the subsystem of vertical dissection in the fourth­ order drainage basin system, is at this hierarchical level characterized by normal distribution of fluctuations, but becomes negatively skewed in the fifth -order drainage basin system. it can be stated that in this case only the m inority of system components in these basin subsys­ tems oscillates in the proximity of the lower limit of the thermodynamic branch (that is , the probability of exceptionally high negat ive fluctuations is very small). pch: frequcncy distribution curves as ,ltl indicator or evolution;)ry trends in geomorphologic;)1 systems ... 87 it suggests that the potential energy in specific parts of a system is so low that existing structures (landforms) undergo spontaneous degenerat ion in the places where its magnitudc falls below some critical value necessary for maintaining the stationary state. a reason for this can be found either in the unfavourable mechanical properties of the underlying bedrock (high permeability and low cohesion of rock and soil material), or in vary­ ing rates of uplift that affect some major tectonic blocks in the area of invcstigation. if the fonner is case, the vallcy-sidc slopes tend to form lower angles due to ineffective st ream downcutting (caused chiefly by rela­ tively high infiltration capacity), which is most conspic­ uously reflected in higher-order and larger drainage basins (fourthand, particularly, fifth-order). in the lat­ ter, denudation processes give way to aggradation processes when the uplift only slightly exceeds or evcn tends to be lowcr than the rales of denudation. as an example, in the subsystem of erosional levels onc of the key variables thc main-valley mouth (which is also the mouth of a referring drainagc basin) represents an overt indicator of uplift and subsidence that can be helpful in disclosing "act ive" and " inactive" gcologic structures in a landscape. obviously, due 10 their rela­ tive lag in respect of the general uplift typical for the study area (prelogoyic, 1975), some tectonic blocks have considerably lower potential energy with respect to the surrounding area, inducing the processes of aggradation and development of "inactive" geologic structures. both cxamples show that the energy expen­ diture in these subsystems occurs mostly at the lowcr hierarchical levels (peh, 1992, 1994). 4. conclusions examples presented in this study show that variolls landforms in the fluvial landscape, such as the north­ western part of hrvatsko zagorje, can pursue different evolutionary schcmes which can be discerned from the corresponding frequency dist ributions of riuetuations. the thermodynamic theory of non-equilibrium states and related fluctuations as the source of instability is the kcy clement in the interpretation of evolutionary trends in gcomorphological systems and their subsys­ tems. this results from utilizing new insights in funda­ menta l physics in the geological sciences. it has been shown in this study that thrce types of frequency distribution curves exist which, in a thermo­ dynamic sensc, can be indicative of equil ibrium and non-equilibrium relationships between driving and resisting forces in land forming processes. they show how landforms try to adjust themselves with minimum internal change to the external driving forces. the example of the processes responsible for the develop­ ment of the subsystem of drainage density and subsys­ tem of hypsometric integral is presented. non-normal frequency distribution of systcm para­ meters indicatcs non-equilibrium conditions which give rise to non -linear relationships between process and form and, accordingly, to structural instability within specific subsystems. such a case is demonstrated by both the positive and negative skew of distribut ion fre­ quency curves. positivc skew is indicativc of structural changc which is the response to strong energy inputs from the system surroundings. the loss of structural stability and emergence of new and more complex landforms is the final result which spurs landscape evo­ lution. an example of this was shown by thc processes accounting for drainage network expansion (horizontal dissection) and, to some extent, by the proccsses of val­ ley incision (vertical dissection). negative skew, on the contrary, can suggest structural changes distinguished by the lack of energy in a system, which is insufficient to reinstatc thc original equilibrium conditions and, thus, to sustain existing landforms. this case predicts the downward path to landscape degeneration, that is, its involution. such a case is exemplified by the process­ es affecting valley-slope angles and erosional levels. although the relevant space and time scales have been taken into consideration, this st udy has been put into a frame which, in a geomorphological and geologi­ cal sense, could not be str ictly viewed upon as regional. however, the results point to distinct evolutionary laws that rule the development of a fluvial landscape in the temperate climate zones. further investigations should therefore be directed toward the spatial evaluation of thermodynamically specified geomorphol ogical para­ meters with assistance of the relevant maps ("process maps", peh, 1994). attention should also be paid to the concept of geomorphological thresholds and bound­ ary values delimiting landform stability. this would allow individual landforms and their evo lutionary (or, contrari ly, degenerative) changes to be directly related to geological struclurcs, lithological characteristics and tectonic activity. acknowledgments during preparation of this paper the author benefit­ ted greatly from critical comments by prof. eduard prelogoytc (faculty of mining, geology and petrolcum engineering, university of zagreb, croatia) which were cxt remely valuable. his help is grateful ly acknowledged. also, the author is greatly indebted to prof. simon pirc (institute of geology, universi ty of ljubljana, slovenia) for his thoughtful reviews and use­ ful comments on earlier drafts of the manuscript. thanks are also due to all my colleagues who supported me in this erfort. 5. references brush, m.ljr. (1961): drainage basins, channels and now characteristics of selected streams in central pennsylvania.u.s. geo!. survey prof. paper, 282f,145-180. bull, w.b. (1975): landforms that do not tend toward steady state.in: melhorn, w.n. & fle­ mal, r.c. (cds.): theories of landform develop­ ment. allen & unwin , london -boston-sydney, 259-263. carson, m.a. (1971 ): the mechanics of erosion.­ pi on, london, 174 p. chorley , r.1. (1962): geomorphology and general systems theory. u.s. geol. survey prof. paper, 500-b, 10 p. chorley, r.1. & kennedy, b.a. (1971): physical geography: a systems approach. prcnticehall intcrnational inc., london , 370 p. coates, d.r. & vitek , j.d. (eds.) (1980): thresh­ olds in geomorphology.allen & unwin, london­ boslon-sydney, 485 p. da vi s, lc. (1986): statistics and data analysis in geology. 2"" edition , john wil ey & sons, new york, 646 p. d1mentberg , m.f. (1989): slucajnije proeessi v dinamiceskih sistemah s pcrcmcnnimi parametra­ mi. nauka, moskva, 175 p. glansdorff, p. & prigogine, i. (1971): ther­ modynam ic theory of structure, stability and ouctu­ ations.john wiley interscicnce, new york, 306 p. hart, m.g. ( 1986): geomorphology pure and applied.allen & unwin, london, 45 p. howard, a.d. (1965): geomorphological systems­ equilibrium and dynamies .am. jour. sc i. , 3023 12. karcz, i. ( 1980): thermodynamic approach to geo­ morphic thresholds.in: coates, d.r. & vitek, j.d. (cds.): thresholds in geomorphology. allen & unwin, london-boston-sydney, 209-226. kei zer , j. ( 1987): statisticeskaja tennodinamika ner­ avnovesnih processov.mir, moskva, 607 p. ki ng, r.i-!. ( 1967): the concept of general systems theory as app licd to geomorphology.albertan geo­ grapher, 3, 29-34. knori ng, l.d. & dec, v.n. (1989): geologu 0 m3temalike .nedra (leningradskoe oldeleni e ), leningrad, 208 p. koch, g. s. & link, r.f. (1971): statistical analysis o f gcological dala. dover publications inc ., new york , 438 p. leopold, l.b & langbein, w.b. ( 1962): the concept of entropy in landscape evojution. us geol. survcy prof. paper, soo-a, 20 p. geolog ia cro:tlic:t 50/1 melton, m.a. (1957): an analys is of the relat ions among e lemen ts of climate , surface prope rties and geomorphology.columbia univ., dept. geol. , omce of nav. rcs. , project nr 389-402 , 102 p. nicolls, g. & prigogine, i. ( 1977): sc lf-organiza­ tion in non-equilibrium sy stems.wiley-inter­ science, new york, 491 p. pattee, h.h. (1973): hierarchy theory, the challenge or complex systcms.braziller, new york, 156 p. peb, z. (1990): app lication of factor analysis in dynamic geomorphology.geo l. vjcsnik, 43, 59-67. peb, z. (1992): factor model of the geomorphological system of a part of northweste rn croatia. geologia croatica, 45, 163-1 72. peh , z. ( 1994): faktorski model kao izraz dinamike geojoskih procesa l1a primje ru sjevc rozapadnog dijela hrvalskog zagorja.unpublished phd. t he­ sis, university of zagreb, 162 p. prelogovic, e. (1975 ): neot ekton ska karta sr i-irvatske.geo!. vjesnik, 28 , 97108. prigog ine, i. (1978): time , structure and f1 uctua­ tions. science, 20 1, 777-785. prigogine, i. & stengers, i. (1985): order out of chaos.flamingo, london , 349 p. ritter , d.f. (1978): process geomorphology.v.c. brown publishers, dubuque, iowa, 579 p. ritter , d.f. (1988): landscape anal ys is and the search for geomorphic unity.geo!. soc . am. bull. , 100, 160~171. scheidegger, a.e. & langbein, w.b. (1966): probability concepts in geomorphology. u.s. geol. survey prof. paper, 500-c, 14 p. schumm, s.a . (l973) : geomorphi c thresholds and complex response of drainage system s.in: mori­ sa wa, m. (cd.): fluvial geomorphology. allen & unwin, london-boston-sydney, 299-3 10. schumm, s.a & lichty, r.w. (1965): time, space and causality in geomorphology.am. jour. sci., 263 , 110-119. strahler, a.n. (1952): dynamic basis of geomor­ phology.geo!. soc. am. bull. , 63, 923-938. wood , b.1. & fraser, d.g. ( 1977) : elementary thermodynamics for geo!ogisls.oxford university press, oxford, 303 p. manuscript received march 15, 1995. revised manuscript accepted april 28, 1997. geol. c roat . 50/2 121 123 zagreb 1997 pozdravni govori (welcome addresses) mnogo postova ne gospode i gosi)odo! radostan sam sio mi sc pruzi la poscbna cast danas govoriti na ovom znanslvcnom skupu u povodu 80. obljclnicc :i ivola akadcmika heraka. akademik m il an herak izabran je za izvanrednog clana nase akadcm ijc 1963. godine, a za rcdovitog 1970. godine, prema l ome njegovo vrlo akti vno djelo­ vanje u akadcmij i traje vee pune 34 godi nc. bio je tajnikom razreda za prirodnc znanosti !lase akademijc i dugogodisnji potprcdsjednik i clan predsjedni stva akadcmijc. to je vid lji vi d io njegova djclovanja u akadcmij i, ali samo za vanjske l1l o1rilc ije lioclji v. medutim, manjc liqc ljiv dio bil a je briga za izdavacku djela tnost akademije. akadem ik herak bio je, nairne, dugogodisnj i urcdn ik pojedinih akademijinih izdanja i casopisa, a posebice "acta geologica". tu sc proldr. milan herak iskazao vrhunski m djc­ latnikom svoje znanstvcnc discip li ne. u tom prostoru razuma, koji je pozvan cia bude stvaralack i, za ista je akadcm ik herak dao sebe i iskazao se kao vrhunski pokretac i krcator progresa svoje struke, a li nc samo iz svojc discipline vee i sire. casopisi islraz ivackih pro­ grama i ostvarcnja pojedinih siruka pravi sll njihov krvozi lni sllstav, kako mi ncdavno reee nas g lavni tajnik akademijc, m. mogus. ali, to je dokaz bogatog slvaral ackog iara koji je temclj na karakteri stika akagospo(1c i gospodo, kolcgicc i kolcgc, stovani akadcl11ice i dragi profcsorc, velika mi jc cast i zadovoljstvo s lo vas mogu poz­ dravi li i ces li la ti ovako znacajan jubilej 1i imc zapo­ s lenika rudarsko-gcojosko-naflnog fakulteta i , nara­ vno, svoje osobno im c. uz cest itke upucujemo yam i rijeci zahvale za svc ono sto sic uciniii za nas rakultet. nai mc, vi i vecina vjerojatno znate, no ja e ll ipak pod­ sjetiti, da je profesor herak zapocco svoj u nas tavnicku karijeru na rudarskom odsjeku tchnickog fakulteta. na tehn ickom, odnosno kasn ije tehno loskom fakul te tu djelovao jc od 1952. do 1959. godine. prcdavao je opeu gcojogiju, slratig rafiju i inzenjcrsku geologiju i hidro­ geologiju. pripremajuci se za ovaj skup saznao sam da je profesor herak 1958. godine izdao inte rna skripta iz inzcnjcrske gco logij e, s to je nes umnji vo prvo djelo s toill tematikom na hrvatskom jeziku i bilo bi zanimljivo dcmika f-ieraka. osim svega toga akademik herak bio je i voditclj mnogih odbora akadem ije kao npr. odbo­ ra za krs, oclbora za geolckton iku , odbora za priro­ doslovlla istrazivanja i drugih akademiji nih ak tivnosti pa cak i iz podrucja biomedicinskih znanosti. svoje pozdravne rijeci, p rema lome, upueujem u ime hrvatske akademijc znanosti i umjetnosti , nasem slavljen iku koj i je veliki dio sebe ugradio u organ izam nase akademijc obogat ivsi je svojim idejama i svojom ijubav lju pa mu zalo vel ika hvala. duboko sam uvje­ ren da je svakom c lanu a kadell1ij e drago i da jc ponosall slo je c lan te nase stare instituc ije s vel ikim povijesn ill1 pameenjcll1 , kojoj je akademik herak nebrojeno pula iskazao svoju ijubav, mar i odanost, ali c ij enjene gospode i gospodo, budite uvj ereni cia je i hrvalskoj akademiji znanosti i umje tnosli cas i slo illla takva clana kao sto je to akadclll ik herak. hvala mu za njegovu odanost prema akacicmiji, a svillla vama, gospode i gospodo, lakoder zahvaljujemo za organi zacij u i sudjejovanje na ovome znanstvenom skupu. akademik ivo padov an potprcdsjednik hazu (vice-president of the croatian academy of sciences and arts) pronaci koji primjerak ukoliko j c sacllvan. no, os im kao nastavnik, profesor herak ostavio je traga na nasem fakulte tu i kao rukovodite lj. bi o je duze vrijeme pred­ sjednik zavoda za geologiju i paleonlologij u , a aka­ demske godine 1957/58 obnasao je i duznost starjcs ine rudarskog odjela, pa je nesumnji vo i njcgova zaslu ga sto jc taj odjel prerastao u fakultet koji danas broji 20 redovnih profesora, 12 izvanreclnih profesora, 11 doce­ nata, 6 predavaca, 40 asistenata i j 1 znanslveni h nova­ ka. u ime sv ih njih zelim vam clobro zdravlje 1 jos mnogo akt ivnih godina. 1 jos jednom: hv ala! prof. dr sc. darko ma y er dekan rgnf-a (dcan of the faculty of mining, gcology and petroleum engineering, university of zagreb) 122 postovani uzvanici, sudionici znanslvcnog skupa 11 povodu 80. obljctnice zivota uvaicnog akademika milana i-1eraka, gcologija jc na svcucilistu u zagrcbu najstarija i najzas luznija grana prirodoslovlja, s kojom zapoci nje naslava prirodoslovlja na modernolll sveucilislu davnc 1876. godine prcdavanjima cuvenog gjurc pilara. od tacln gcologija jc dala najc livcllija imcn3 hrvatskom prirodoslovjju, kojima sc pridruzujc i imc danasnjeg iaurc31a, profesora milana hcraka. milan he rak jedan jc cel znanstvcnika i intc lektua­ laca bcz kojcg bi nasa prirodoznanstvcna zajednica bila bi lno siromasnija. poi reba za prirodoslovcclll mogla bi sc clefinirati kao potrcba za kriticnim misijenjcm, a kriticno mi slje­ nje kao temelj ni prcduvje t znanstvene edukacije. z nanstve nik njegovog formata potreban jc svim drlls tvimu u sv im druslve nim slojev ima. to su znanst­ veni c i koji vide kvaziznanos l, di skuliraju posljedice znanslvcnih dos li gnuca, li smjeruju rasprave sociologa, llj11j elnika i polilicara, poducavaju, pi su i sire spoznaje podi zuei opell razi nu znanja c ije loj javnosli. 0 lakvom znanslvelli ku bit ce dallas ovdje rijcc 0 milanu i-icraku. taj zasluzni hrvalski j11u z posvetio je punih sczdese t goelina svog z ivota proucavajuci priroelu svoj e domo­ vin e. to je razlog sto smo se povodom njegovog 80. stovani gasp. akadcmicc herak, stovana gospodo herak, posebna illi je cast 1i ime sllorganizatora ovog skupa institllta za geoloska istraz ivanja pozdraviti gospodina akaclcm ika milana heraka, cloajena geoloske slruke, koj i iako mlacl duhom danas slav] 80. obljc tnicu zivota. respcktabilne su 10 godille, al i jos je respeklabilnije closadasnje dje lo naseg slav ljellika. vec ina nas cljclatnika ins tituta bili smo i jos smo uvijek claci prof. heraka. brojlli ispili , diplomski, magi­ starsk i i doktorski radovi radeni su pod budnim okoill naseg clragog profesora, koji jc uvijek s puno s trp ljcnja i mllclrosti prenosio svoja znanja na nas nesto mlade. u velikoj mjcri se moze zalwaliti lipravo prof. her­ aku cia je hrvatska geo loska znanost pratila i cak una­ prcdivala svjc tsku geologiju. rezulta ti njegovog djelo­ vanja prepoznatljivi sli u razlicitim geo loskim d isc i­ plinama s to je imalo izravnog utjecaja l1a znanstveni i islraz ivacki rad mnogih gcoloskih i s rodnih institllcija, pa tako i instituta za geoloska istrazivanja, gdjc.ie nje­ goy doprinos takoder zl1::lcajan. dio znanja prof. he raka ugraclen je u sve gcoloske karle, koje su tcmeljni program lnslituta kao jayne znageologia croallca )u/l rodendana okupili danas ovdje da mll odamo pocast i zahvalimo mu si o je bio tu i !ito je danas s nama. sigur­ na sam cia cc 0 vaznosti ove proslavc za geologiju biti jos mnogo rijec i tijekom danasnj eg dana u va.5 im izla­ gallj ima , al i is to tako da ce iz njih izaci na vidje lo cilljenica cia bismo, kad bi cljelo profesora heraka zcljc­ ii poblizc svrs tati u cv rs tc obrascc geologij e, zapali u vclike probl cme. je ii on geolog, paleontolog, antro ­ polog iii jednostavllo prirodoznan slven ik? prava jc sreca cia sc clisci plinarne granicc ne podudaraju s intc ­ icktllalnim utjecajem ovog sves lranog znan stvcnika kojeg je kroz cijc li :l ivot vodio njegov naglaseno vclik iclealizam. nadam se d a ce nas tojanja i iruel koji s u organizatdri uc inili , kako bi makar s imbo licno nagradi li svog uvazenog ucitelja , biti ohrabre nje ka izglcel im3 za bolju bueluc l10s t geo log ije i priroeloslovlja n<l sveuci­ li s tu 1i zagrebu kojem j e profesor mi lan herak tako preelano s lllzio. u ime pmf-a, sreln og faku lteta cij im s tude lltima i suradnicima sle bili ne posredan uc it c lj , ces litam yam profcsore herak sretan rodcndan. prof. dr sc. bi scrka nagy dekanica pmf-a (dean of thc faculty of sciences, university of zagreb) nslvcnc ustanove, a osobito 1i geolosku kanu rcpub­ likc hrvatskc m 1:50.000, koja kao dinamicki modeli ­ rana karla objcdinjuje brojnc geoloskc aklivj10s ti 1nsti­ tui u. no, i ostali d ijclovi instituta elanas praklick i u sv im svojim radovil11a c itiraj u prof. heraka, jcr 111 0bilis licki pri stup tektonskim interprclacijama geoloskih struktura olvara jcdno novo polje cljelovanja hrvatskim geolo­ z ima, a posebno hiclrogeo lozima , koji takovim pris­ lupom postajll prepoznalljivi u svijetu . kako iza iii uz svakog velikog covjeka s toji zena tako i mi danas imamo prigodll 1i ime geologa zahvaliti gos podi he rak na velikom strpljcnju i odri canju , j er manje iii vise znamo 510 znaci znans tvenoi strazivacki rad , koji je i obveza i hobi u koji se prakti cki 1iiaze cijcli zi vo l. zahvaljujemo gospoelinu akadcmiku na closaclasnjoj suradnji i uzdamo se u vase zdravlje i mogucnost dalj ­ nje suradnje s nama geolozima u institutu. dr sc. bozidar bi0ndic ravnatelj jnstituta za geoloska is trazivanja (director of the institute of geology) :-'okac; .~(i/f'/iiko/xh('ii(i to/mst(l n.sp ... postovani siavljenice, dame i gospodo, ovom svccanol11 prigodom gcolo.~ ko palcntoloski odjcl h rvatskoga prirocloslovnog muzcja clodjcljujc akadcmiku milanu hcraku spomcn meclalju s povcljom ii znak priznanja i sjccanja na gotovo dcselljecc racla kojeg j c prafesor prove~ 1i geoiosko-palconloloskom illuzcj u. spomcn illcdalja je izradena ujesen 1996. god­ inc u prigocli proslavc 150. obljctnicc ulclllc ljcnja naro­ clnoga muzcja u zagrcbu, ciji je gcolosko-palconloloski muzcj bio s ljcd nik. mogu s rad oscu rec i cia jc illuzcj ski i ll1uzco loski rad profesora hcraka, mada na pocetku njegovc karijcre visokostovani i dral4i profesorc, stovana gospodo herak, stovano predsjednistvo i uvazeni skupe, vel ika mi jc cast i zadovoljstvo izici prcd ovako vc licanstve ni skup i kazati da jc mala rcgija nadomak illc lropo lc sreln a sio u zadovoljs tvu l11 ozcmo s vallla proslaviti 80. obijc tnieu yasega z ivota. uz zadovoljslvo 1110ral110 kazati cia je clanas i nase srec isplinjcno p0110som kacla vidimo tako pomno priprcmljcn znanstvcni skup posvcccn yasclll i ivotnom cljc lu. iz drustva, koje nos i casilo ime i lerodota hrvatske povijcsli tadijc sm ic iklasa, a koji jc roden u neposrcd­ noj blizini vase roclne bras ljeviee, donosimo yam pre­ g rst ccstitki i dobrih zelja za dug i sretan zivo!. danas cc ovclje bili mnogo rijcc i 0 vasclll bogata ispunjenom zivotu , 0 dostignu cim<l koja su olkrila mlloge slvari u svijctu znanosti i s ve likom pozornoscll ce ltio 10 ovdjc saslusati i prenijeli vasilll brojnim stovatcljima. a sto vam vasi 7.cmljaci clanas loclc kazati i uruciti? zc lc kazati cia su ponosni na vas. da sic uspje li najsadrzajnije ispuniti zivol a sto znaci ispuni li saclrt.ajno iivot? to jc lesko i kompleksno iivolno i filozofsko pita­ njc. na njega jc jl10g11cc iz raznih llglova clavali odgo­ yore. sazimati ill 11 jednu recenicll iii razlagali u bcskra­ .inc (corije i raspravc. sivari se pojeclnostav ljujll kada 0 (oj (emi porazgovaramo obienim , narodnim m islillla i rijecima. kad a 0 taj icmi zavirimo u lekslovc velik ih ijudi koj i nis li izgubil i svoj u svczu s naroclom. za ovu prigoclu odabrao sam nekoliko mis li iz \jed­ nika zumberackc novine (urecl nik cl l'. janko silllrak, svcuc. profesor i kasnije biskup) u kojima sc oci1ava lik naroclnc svct inj c zulllberackog haja. opisllje sc covjek koji jc li spio u z ivotu. radi se 0 covjeku iz naroda koji je svojilll casnirn i ivoioill u na­ rodu posl igao sve: i ijubav i s tovanje. uzornog pona­ sanja kod kuce 1i odgoju djecc, primjcran mcdu l1a ro­ dom. karizmatska osoba, voda savjetnik , miritclj zava­ dcnih. osoba koja je svojim krsca nskim z ivo(om zra­ eila, praklicni katoiik koji jc tesko bol cslan prevaljivao nckoliko kilome (ara pjcsice, a kacla mu to nije bilo illogucc uzjahao bi konja da stigne obaviti svoju krsca123 u teskim godinama rata i poraca, bio islo tako vazan i plodan. kao sto je bio i njegov kasniji zil cllls tve ni i nastavni rad. cast mi je slo illogu kao voelitcljica gcol osko-pale­ on toloskoga odjela u imc svih kustosa ees titati profc­ sorli ovulijcpu obljc tnicu zivota i rada. mr sc. ziata juris ic-polsak vocliteljica gcoiosko-palcontoloskog odjcla hrval skoga prirocloslovnog muzcja (i lcad of the geological-palaeontological dcpartment or the croatian natural history muse um) nsku dllznost, a poslijc mi se da se sll srctne sa svojim naroclom kojeg jc sv ilovao, razlagao mu , tumac io i upucivao u dobro, poput naroclnog ucilclja. profcso r simrak ni lc ii tom tekstu jos c ijeli niz clrug ih vrli na od onih rocloljubnih , lokalpatrio lskih. druzeljubivih, rodi tcljskih , da bi zavrs io leksl 0 covjcku koji je najplcmcnitije ispunio svoj zemaljsk i z ivo t. ovo i11 prigodom nccu vi se duziti. radijc ell nasem dragom svccaru uruc iti pres liku tih novina kao znak sjecanja i podsjetnik cia p lcmenito ispunjen zivo t ostajc 1r3jno zapisan i njegujc sc u naroelu. preslika ce mu bi ti poscbno draga jer ocrtava lik koji bi 1i ovoj prigocji on najrad ije vidio u ovoj dvorani. rijec jc 0 naroelnoj sve­ tinj i ju ri i-ie raku iz bras ij evice, oell naseg slova nog profesora. zas to sam sve ovo izgovorio? zato j er mislim da ovaj uvazc ni skup, koji se bavi zivotom i djelom akaclcmika hcraka, treba clo znati i ncsto 0 temcljnoj kariki u tome lanel! i slll a tram cia la karika nc smije biti ispustena, demas, a niti za taman lol iko godi na, kada se ncki drug i ljudi sas tanu, cla bi se sjc tili vcli kog :livota i djc la akaelemika milan3 l-l e rak~l jcr filozofska jc misao i istina: "u oblikovanju oso­ bn osti j edan j e olae vi se nego stoti ml uc it c lja!" (georges herbert). stov<lni gospodi nc profesore, srctan yam 80. rodendan, a kao mali znak paznje d opustile cia yam avo drustvo kojem stc i yi 1934. godine bili j edan ael uteme lj ile lja uruci gore rcccnu presliku iz 1939. godine i pove lju u kojoj smo zapisali: "uvaiej/om i dragofj/ akademiku milam/ h ernkll l/ povodl/ 80. obfjelflice i ivota povelfa zifmberakje pollosall sio vas ima. zaliwt/jllje vam za .n 'e sio sle utillili za rall 'oj /"oelllog kraja i ieli vam dl/x i srelall i i\'ol." petar badovinac. odvj. preclsjcdnik drustva zumbcrcana "taclija smi c iklas" (pres ident of the zumberak soc ie ty "tadija smiciklas) 124 geologia crojl ica 50/2 geol. c roat. 50/2 1/47 149 1 1 zagreb 1997 morphological variability as a basis for palaeontological classification iakov radovcic on the occasion of the eighti eth birthday of profes­ sor milan herak, it is certai nl y our responsibility and pleasure to trace the many articles and other works that highli ght the professor 's scientific contribution to croa­ tian geology or palaeontology. given that it is exactly fifty years aftcr the publication of one of professor her­ ak's palaeontological works, this is a relatively positive chronological distance from which it is possible to eva­ luate his contribution to our field. tn his exceptionally prolific professional li fe, pro­ fessor herak spent almost a decade, 19431952, as a curator in the geological and palaeontological museum in zagreb. here, he was concerned with research into the rich osteological collection of cave bear remains (urslfs spelaclfs) that the museum possessed, and this work culminated in the publication of a fairly large sci­ entific work, in 1947, entitled "starost i sistematske znacajke spiljskog mcdvjeda hrvatske"' (the age and systematic characteristics of cave bear of croatia). there arc many reasons this is a pioneering work in the history of croatian vertebrate palaeontology, following the sign ifi cant offerings of herak's predecessor in the museurn professor dragutin gorjanovic-kramberger. at this time new theoretical hypotheses and new syn­ theses of evol utionary theories were applied globally to the past and present world resulting in greater under­ standing of evolutionary mechanism of biological cha­ nge. herak's 1947 paper is a good example of how , even in our lime it is necessary to understand the theo­ retical foundations of various methodical and palaeon­ tological classifications, determinations, and systemic organizations, in order to understand the various mor­ phological entities, throughout geological history which rcpresent once living organisms. herak was concerned wi th the morphological vari­ ability of an extinct species, and within the context of samples available in the museum, he attempted to define the theore tical and practical bas is for the taxo­ nomic determination of a fossil species. different theo­ retical app roaches to taxonomic classifications have department of geotogy and palaeontology, croatian mu seum of natllral history, dcmclrova i, hrj 0000 zagreb, croatia. existed from the period of linnaeus and attempts at identifying the living and non-living world in the natur­ al sys tem of "scalae naturae". if discovery is merely the first distinct phasc of scientific activity, then descri­ ption and subsequent categorization, i.e. systemization of such discoveries follow, leading to a final, complete synthesis, and comprehension of the totality and causa­ lity of the world that we are studying. herak incorpora­ ted all those levels of scienti fic inquary in his approach to science from the very beginning. it was already young charles darwin who wrote that geologists when deriving facts from the past need not always begin with the description of the colour or size of a pebb le of gravel discovered in a complex of depo­ sits. considering the diversity of the grave l, distin­ gui shed by many detai ls or a classificatory typology, they would need, according to darwin, thousands o/" years to describe the divers ity of all the gravel of the world. we cannot know whether these sentences or darwin were to determine herak 's approach in 1947 to studying the different "variet ies" or numerous featu res of fossil finds of cave bears in the collections of the zagreb museum, bu t herak's sentences indi cate an advanced level of theoretical knowledge and pract ice in the methodological approach to scientific work. "thus we also sha/! 1i0t consider our material separately, rather we sheill affempt to estahlish its relation to the whole ... ", writes professor herak, " ... in this manner we shall cstablish thc systenwtic significancc of our cave hear, meaning that we shall he able to establish whe­ ther it can be considered a typical representativc (~f the species ursl/s spelaclfs , or whcther this \ovas somc kind of new variety or race". such refl ecti ons are not far from the fund amental v iewpoint of every palaeontoio­ gist today. herak 's starting point for studying the varied cave bear rema ins, from diverse, ice age deposits and si tes throughout croatia, represented for many, a new appro­ ach to distinguishing and understanding the complicated variability or "typologi es" of individual organi sms . tt this paper was presented at the scientific meeting dedicated to the 80th anniversary of the life of professor milan herak, held on march 5th, 1997 in zagreb 148 was then neccssaly further to comprehend what is in the subs tratum of many biological processes, which afc eventually deciphered through the morphology or mor­ phometry of pctrified bones. before we state the current judgment about this innovative work in croatian palae­ ontology by professor herak, it is necessary for lis to remember several almost general facts from the history of the palaeontological sciences. the fundamental methodological starting point [or cietci111ining a foss il as some kind of document or entity according to which we classify and reconstruct the history of life on earth has been known, probably from the 18th and certainly from the beginning of the [9th century. if the theory about the evolution of the living world , which originated in the middle of the last century, changed the central con­ cept of palaeontology, then the 1940's were the origin of the so-called synthetic evolutionary theory as a sort of scientific, kuhn-derived paradigm, in a modern view of population biology. the works of huxley, fisher, mayer, stebbins, wright, and in palaeontology, g.g. simpson, changed the concept and approach to the study and understanding of variability, and subsequent­ ly the evoltllioll of the organic world. 11 should be emphasized that the first scientific activity of herak in palaeontology corresponds 10 the years of the appear­ ance of new syntethic theory of evolution of the organic world, and in this context, herak's 1947 paper is a sma ll , but significant con tribution from croatian palaeontology to world literature that marked this per­ iod. many modern books about the evolution of species teach us today thai nothing is worse for evaluating the work of a scientist studying the history of organic evo­ lution than an evaluation that someone in approaching a palaeontological determination of a fossil e ntity has gone no further than looking altypo log ies, the dist inc­ tion of a particular entity for which no biological s ignif­ icance is known of the complicated process of variabili­ ty. the color or size of those gravel pebbles of dar­ win's, or the greater or lesser skull size of some animal, yet another secondary cusp on the molar of a large mammal, or some other isolated morphological fcature, are not in themselves the means by which the variabili­ ty of the organism is expressed, if in this we forget that no single leaf is identical to another on a many branched trec. "ideal types" or even "morphotypes" arc only the philosophical fiction of our artificial, often subjective conceptual approach to the systemics of the organic world. thus herak, with his work on the hete­ rogeneous cave bear remains, began to move away from the current typological viewpoint of the palaeon­ tological determination of biological entities. "large" and "small" bears and morphometrical large and small organisms existed once and exis t now. establishing their existence is perhaps merely manufacturing a record about some of "darwin's gravel", but studying the size, form, and structure of many pebbles, their ori­ gin, genesis, and much else relaled to the pebbles requires much greater knowledge about the mountain geologia c roatic;l so/2 from which the pebbles were derived , the [orees that rolled them, and the rock from which they originated. today we know that typological conception, the dis­ tinction of types and morphotypes represents the oppo­ site to considering evolution through all individuals, the population of a given type from the area of its existe­ nce. as herak stated, " ... in the first beginnings 0./ rese­ arching the cave bear, they tried to ilote the forms i-vhi­ ch differ to a great extent from the rest as varielies. in this mallller, they ascribed some systematic classifica­ tion. however, more recent research", and here profes­ sor herak states, following professor ehrenberg of vienna, " ... shows that there are no secure criteria or scient~fic basis according to which each phenomenon o.t variability need be noted as a variely.", (i.e. morpho­ type) with clearly established sys tematic boundaries of independent classification. "all of this caused liie criti­ cally to collsider the material frolll ollr sites alld to ask if withih this material there existed a forl1l tha! we could denote as a special variety or race o.lthe species urslis spe/aells, i.e. do forms exist among them that agree ill principle with the others? bur according to so­ me characterislics, which must in general be o.f a grad­ ual i/ature, they occupy al/ isolated and constallt spot iiot merely among the forms from their own site, bllt also withill the general variant curve." herak was particularly concerned in this study with the morphological variability of the cave bear remains from the classic pleistocene s ite at krapina. its excava­ tor, d. gorjanovic-kramberger, allempted many times to examine the possible homogeneity of morphological variability in distinguishing species, varieties, races, types, and so forth. in his palaeoanthropologieal works he strongly resisted distinguishing various types of ancient hominids at the krapina sile, instead writing more about the mechanism of perceived morphological variability. thus according to gorjanovic-kramberger, "homo hauseri" or "j-j. allrignaciel1sis" did not ex ist at krapina, but rather the variable model "j-j. primigenius" (radoycic, 1988) in contrast to the views or kla­ atseh (klaatsch & hauser, 1910). similarly, when gorjanoyic-kramberger (19130) allrib­ uted the remains of a cave bear, or in another work a rhinoceros (gorjanoyic-kramberger. 1913b). to indiv idual varieties or systemat ic categories, such as "race" or "breed", which he names as "krapiniensis" types, then this is more an expression to distinguish another population, which is chronological ly or geo­ graphically separated [rom the comparative sample. in this segment of gorjanovic-kramberger's theoretical basis li es the beginning of the modern population approach to systemics, while in the work of herak it is already a working hypothesis. thus, in the morphologi­ cally "irregular" crown or the molar of the ursl/s spelel/s species from krapina, or in the diverse skulls and teeth of this animal from other pleistocene sites in croatia, herak sees merely an emphasized morphologi­ cal variability over a wide area or a greater stratigraphic span of available samples. it was ol1ee thought that the r:ldov'::i(:: morphological v:lriabi lity as a ila;;i ~ ror p;ilieoli toiogicai clas~ ifi calioll " krapina sequence" could represent a long pleistocene spa n from the last interglacial (riss-worm) to the penultimatc wurm stage (malez, l970), and thus a lengthy ch ronological sequence that would eventually justify the ex istencc of a special taxonomic unit. more recent determi nat ion or the absolute age of the krapina site indi cates all entirely short stratigraphic span of plei s toce ne deposits a t krapina (rink ct. ai., 1995). thu s the wo rk or herak (l947), was a correct and sui tabl e tec hnique for croatian palaeontology in that period. unfortunately, a broader analysis of the palae­ ontologica l works that were to rollow herak's text show a significant deviation from thi s work that could have served as a model. in conc lusion , herak es tablished that individual exa mples of osteological material do not offer a basis for es tabli shing certain vari eties and races in the study or the characteristics of individual taxonomic entities . all dilfe rences between individual form s clearly can be cliltcrcnces of individual variability resulting fro m a combination or many biological mechanisms. thus it seems justified to s tat e toelay that herak in 1947 first introduced into croatian palaeonlologicalliterature, the principle of populational approach in the classification of certain morphological variants, and that this occurred simultaneolls ly with the first similar attempts in interna­ tional lite rature . finally, it seems to me today that oftcn in the lack or theore tica l and practical qualifications, as well as in ignora nce of the modern developments in palaeonto­ logy as a scientific discipline, in our profession and the pseudo new morphological considerat ion s, the typolo­ gica l manner or studying the fossil world is again beginning to appear, the es tablishment of specificities without taking into account the integrity and context of the tota lity, and even the entire organism. sometimes certain works remain at the level of the study and dis­ tinc ti on of individual c lements (as the ancient greeks saw in rire an clement instead of a prod:ss). inasmuch as research into the organic world of the geological past is also rescarch into the once extant organic process, the dynamic re lation between population and the environ­ ment in some period, then the achievements and know­ ledge that herak published fifty years ago is a founda ­ tion s tone that we need not speedi ly rill over. his dis ­ cussion about the systemization and characteristics of the cave bears of croati a, printed in 1947, at the begin­ nin g or hi s prolific and many-faceted scientific career, remain s a c lassic lesson even for the rcsearchers of today. 14(j references herak, m. (l947): starost i sistcmatskc znacajke spiljskog medvjeda [-lrvatske (age and systematic characteristics of cave-bear of croatia).geo!. vjes­ nik, j (l947), 12-47. gorjanoyic-kramberger, d. (l913a): zivot i kultura diluvijalnoga covjeka iz krapine u hrvat­ skoj (homo diluvialis e krapina in croatia vita et cultura).djela lugos!. akad. zn<:\n. umjetn., 23, 154, zagreb. gorjanoyic-kramberger, d. (l9j3b): fosilni rinoceratidi hrvatske i slavonije s osobitim obzirolll l1a rhinoceros mercki iz krapine.djcla lu gos!. akad. znan. umjetn. , 22, 1-70, zagreb. klaatsch , h. & hauser , o. ( 19jo): holllo alir;­ rj/gciensis hauseri. ei n pahiolilischer skclettfund aus dem untercil aurignacien del' station combe­ capelle bei montferrand (pcrigord).prahislorische zeitsehr., 1, 273-338. malez, m. (l970): novi pogledi na strat igrariju kra­ pinskog nalazi'ta. in: malez, m. (cd.): krapina 18991969. jugoslavenska akadelllija znanosti i umjetnosti, 13-44, zagreb. radoycic , j. (1988): dragutin gorjanovic-kram ­ berger i krapinski pracovjek. poeeci suvremene paleoantropologijc. (dragutin gorjanovic kram ­ berger and krapina early man. the foundations of modern palcoantropology). skolska knjiga, zagreb, 176 p. rink, w.j., schwarcz, h.p. , smith, f.t-l. & ra­ doycic, j. (j995): esr dates cor krapina homi ­ nids.nature, 378,24. 150 lieologla croaiic,\ )u/,l jamicic.indd 1. introduction medvednica mt. belongs to the mountain range which cannot be distinguished structurally or tectogenetically from other mountains of the pannonian basin between the sava and the drava rivers. the same or similar structural morphologies were recognised within the rocks of this mountain, as occur in the other mountains of the area (jamičić, 2000a). the formation of the structures was connected with tectonic events from the palaeozoic to quaternary periods which are tectonically clearly separated (jamičić et al., 1985, and jamičić, 1988, 1993, 1995b, 2000a, b). based on the aforementioned papers, it has been proven that the tectonic events within the laramian phase of the alpine orogeny have resulted in formation of the important structures within the upper cretaceous and older rocks. the structures were finally shaped by the recent n–s oriented stress. in the area of the slavonian mountains, these events resulted in the formation of a complex structure kik–petrov vrh, defined as being approximately 10 km in length with a n–s strike and e vergence (jamičić, 1988, 1993). on požeška gora mt. the structures in the upper cretaceous layers of the bodljiš stream have the “orešje” laramian structure in the ne part of medvednica mt. (croatia) domagoj jamičić been formed with the same e vergence and were also observed in the granitic–rhyolitic part of this mountain (jamičić et al., 1985). tectonic elements of this event can also be seen in the ivanščica, kalnik and ravna gora mts. at the northeasternmost part of medvednica mt., approximately 4 km n of zelina (fig. 1), in the area of donje orešje village, the upper triassic and upper cretaceous carbonate deposits were discovered in a local quarry. limestones containing hippuritids in the donje orešje area were first discovered by foetterle (1861/62). they were described by gorjanović-kramberger (1908) as hippuritid limestones and gosau marls, whereas polšak et al. (1978) have described in detail and documented by fossils four members of the upper cretaceous, ranging from santonian to lower campanian in age. basch (1983) mentioned pelagic sediments and reefal limestones with marl intercalations in the area of the donje orešje. korolija et al. (1995) proved the presence of upper triassic limestones of norian–rhaetian age in the quarry, which are discordantly overlain by upper cretaceous rudist lithosomes. 2. methodology detailed structural measurements of the upper triassic and upper cretaceous limestones on the open profile in the donje orešje quarry, defined the complex orešje structure (fig. 2) as being approximately 500 m long. during these explorations determination and classification at outcrops of all present discontinuity planes (bedding, faults and axial plane) and related structural elements were undertaken, and numerical measurements taken according to their shape and genesis. for the faults with records of tectonic transport, orientation of regional stress has been calculated by the left inclination of a-lineation (ζ). since the most frequently measured discontinuity planes were the bedding planes which also mark the structure, a β-diagram has been made which allowed the position of the fold axis to be constructed. among linear structural elements, the positions of fold axes and axes of r-tectonites have been measured. the presence of fracture systems parallel to the zone of axial plane of folds was determined, as well as conjugated fractures oriented obliquely to the geologia croatica 57/1 87–93 10 figs. zagreb 2004 key words: tectonics, stress, laramian folds, medvednica mt., croatia. institute of geology, sachsova 2, hr-10000 zagreb, croatia; e-mail: djamicic@igi.hr abstract structural features of upper triassic and upper cretaceous carbonate rocks of the donje orešje quarry were formed by tectonic deformation in temporally separated deformational events. the main structure is the complex orešje structure with a n–s strike and e vergence. it is composed of several overturned anticlines in which either similar or different structural forms were observed. the structure was formed by laramian movements during the alpine orogeny when the main stress was oriented e–w. during the youngest tertiary and quaternary movements, the orešje structure was influenced by a n–s oriented stress whch resulted in folding and rotation of the main structural form. 88 geologia croatica 57/1 89jamičić: the “orešje” laramian structure in the ne part of medvednica mt... fold axis and fractures perpendicular to the fold axis. in the zones of intense tectonization, especially in the overturned limbs of the folds, schistosity subparallel to bedding planes occurs. 3. results the complex orešje structure is shown on fig. 2, reconstructed on the basis of the observed and measured structural and tectonic data. it is composed of at least five anticlines, each showing a different grade of deformation and fold index, depending on their position in the complete structure and ductility of the available rocks present. it is visible for almost 450 metres, mainly in the southern part of the donje orešje quarry, which is open along an approximately e–w strike in the valley of the šum stream. at the easternmost part of the structure (fig. 2), upper triassic (norian–rhaetian) limestones occur, in the form of an overturned anticline (fig. 3). in contorted beds, up to 1.5 m thick, crushing of limestones as a consequence of folding is observed. fractures oriented 207/13° which mark the axial plane of the fold, and fractures oriented 16/75° from the zone perpendicular to the fold axis were observed. on the strike-slip fault oriented 120/78°, a-lineation with left angle (ζ) of 3° has been measured. fig. 1 location map of the donje orešje quarry. fig. 2 the reconstruction of the orešje structure: (1) upper triassic, (2) upper cretaceous. 88 geologia croatica 57/1 89jamičić: the “orešje” laramian structure in the ne part of medvednica mt... tectonic transport right-lateral to the fault plane has been observed and based on these data the main stress axis (σ1) oriented 250/3° is defined resulting in the form of an overturned fold. the strike of the fold axis is approximately n–s with a gentle plunge toward the s. the inclination of the b-axis and axial plane of 13° towards the s is caused by younger tectonic events on a pre-formed structure under the influence of stress which was, during the tertiary and quaternary, active in a n–s direction. deviation from the vertical axis (~15°) of fractures perpendicular to the b axis also took place during the younger kinematic event. associated fracture systems in the normal limb of the structure described belong to the extensional fractures parallel to the b axis and were formed by the pushing aside and migration of beds towards the apical parts of the fold. the next structure towards the w (fig. 2) is composed of cretaceous limestones and its structural features also show the character of an overturned anticline. part of the structure is shown by the photograph (fig. 4a). the normal limb (not visible on the picture), is cut off and pushed over the footwall of the anticline. different structural elements are clearly observed showing the intensive folding and the compression of the space. the most remarkable discontinuity planes are bedding planes. their numerical measurements (8 data) are presented on a β-diagram (fig. 4b). the maximum of the β-intersection (169/15°) as well as the sub maximum (339/11°) show the b axis strike of the complex orešje structural segment. the other maxima are accidental intersections. sigmoid folding of beds visible in the right part of photograph (fig. 4a) is the consequence of reverse pushing of the hanging wall of the structure. in the central parts of the photograph “boudinage” structures can be seen; their longer axis is oriented 158/13° and marks the b-axis as well, which completely coincides with values for the b axis of the structure obtained from the β-diagram. the fracture system, parallel to the photograph in fig. 4a, belongs to fractures from the zone perpendicular to axis b. these are open fractures (1–2 cm in size) with an orientation 344/67°; their existence is connected to the extension of the structure parallel to the b axis. on their planes calcite coatings in forms of crystals which crystallized by migration from the source rock in open fracture systems are observed, so it could be assumed that these fractures are the youngest and that they were formed with the layer-parallel slip of limestone. a new structure further towards the w in continuation (their photos can be merged) with the previously described structure (fig. 4a), is shown in fig. 5a. here we can observe the apical part of the overturned anticline overthrust on the previously described structure from fig. 4a. we 1 m fig. 3 the apical part of the anticline in the upper triassic limestones. we fig. 4 a) footwall of the overturned anticline; b) β-diagram of bedding planes from fig. 4a, contoured at 1–2–4–6–8 and 10%. a b 90 geologia croatica 57/1 91jamičić: the “orešje” laramian structure in the ne part of medvednica mt... a reverse fault is gently laid and covered by rockfall material. in contrast to the previously described structure, the folding index is smaller due to the presence of thicker calcarenite beds (in the right part of photograph). the main structural elements remain the same. in calcarenites the faults from the axial plane zone oriented 190/12° with a reverse type of transport of hanging wall are seen. the open fractures are clearly pronounced (187/78°) perpendicular to axis b. similarly, calcite crystals have been observed on these fractures indicating extension parallel to the b axis during fold formation. the strike of the structure is approximately n–s as seen from the β diagram (fig. 5b), made from measured bedding data (8 in total). a strike maximum of 189/6° defines the position of the b axis of the structure and is in complete accordance with measured data from the outcrop (189/4° and 18/6°). the next structure available for observation extends further towards the w. it is composed of upper cretaceous platy limestones (fig. 6) which are folded in metric folds of the “chevron” type. the fold orientation is n–s with e vergence. apical parts of the folds are weakly pronounced or non-existant, as a result of their high folding index. axial fold planes are oriented n–s and are inclined towards the w under the angle of 58°. fracture systems appear parallel to the b axis, splitting the limestone beds into lithons a couple of centimetres up to one metre wide. lithons are disjointed up to 10 centimetres and the interstitial space is filled by terrigenous material derived from the surface. bed separation is noticed (105/4° and 285/74°) as a consequence of folding, indicating that the deformations did not take place at great depth. the fractures from the zone perpendicular to the b axis are also present (parallel to the photograph) with calcite coatings similar to those from fig. 4a. in the furthest n–w part of donje orešje quarry, the apical part of an overturned fold composed of the upper cretaceous clayey limestones is exposed at a height of 12 m. this part of the structure (fig. 7) is overthrust on the previously described folds and has been secondarily folded. the axial plane has e vergence and is relatively gently inclined. the beds are of 74/56° and 74/75° orientation. the fractures from the zone perpendicular to the b axis oriented 165/76° with calcitic crystal coatings are important. sliding of hanging beds during folding resulted in the formation of a small cavern (in the lower part of the photograph), the axis of which is parallel to the b axis of this anticline structure (350/2°). on the photograph (fig. 8) taken on the left side of the cavern (fig. 7), in the footwall part of the anticline fracture systems are visible (riedl fractures, left of the hammer), which were formed by the influence of layer-parallel slip in the apical parts of the structure. the fractures formed domino structures. the intersection between bedding planes and fractures (347/2°) are entirely correlatable with values of the structural axis. in the hanging wall part of the orešje structure (fig. 7) the fractures from the zone perpendicular and parallel to the b-axis are observed as well as a conjugate fracture system diagonal to the axis (fig. 9). this fracture system is generally characterized by folded forms. the we a b fig. 5 a) apical part of the overturned anticline in the upper cretaceous calcarenites; b) β-diagram of bedding planes from fig. 5a, contoured at: 1–5–10–20–25 and 30% we 2 m fig. 6 metre-sized chevron folds in platy upper cretaceous limestones. 90 geologia croatica 57/1 91jamičić: the “orešje” laramian structure in the ne part of medvednica mt... fractures oriented 198/89° (left of the pen), are from the zone perpendicular to the b-axis, which correlates with all other measured data for the entire structure. the conjugate fracture system (below the pen) is oriented 328/62° and 233/64°, indicating that the fractures were created by the influence of stress oriented e–w. there are no traces of movements visible on them, although these should be expected. on the picture (right of the pen) scarce fractures from the zone of the axial plane oriented 276/38° are seen. all the deformations described above were formed in a single tectonic event under a stress oriented e–w. the complex structure has a n–s strike with e vergence. it consists of several overturned anticlines (fig. 2) that are mutually connected with synclines. however, in the overturned limb of the last described anticline, structures formed after the completed shaping of the orešje structure have been found; similar structures are less pronounced in its other parts. namely, there the synclinal folding near the e–w axis within the upper cretaceous clayey limestone is being observed. in the central part of this n–s oriented syncline shown on fig. 10, layers of tertiary deposits occur (badenian), which were primarily discordant over the orešje structure. bedding planes of the upper cretaceous layers were oriented n–s before these deformations, with a plunge towards e, and were folded around an e–w axis. bedding (55/58° and 130/28°) marks the new axis b2 (126/29°) which correlates with field measurements. a major part of the b-axis plunge is caused by bed inclination before the deformation. on the photograph, the old fractures from the zone perpendicular to the b1 axis are visible, which are rotated by younger tectonic processes around an approximately horizontal e–w axis. their orientations are 150/88° (left part of the picture) and 350/42° (right part of the picture). during these deformational processes, the badenian beds (in the upper parts of the photograph) were also folded and disintegrated. only the fractures which are parallel to the axial plane of the newly formed structure b2 appear. 4. conclusion based on the detailed structural investigation of the upper triassic and upper cretaceous deposits in the donje orešje quarry, the complex structure of orešje has been defined. it has been proven that it is composed of at least five mutually connected anticlines formed during the same deformation event. dating of these events is defined by the position of tertiary deposits which are discordant to the orešje structure. by correlation of the characteristics and genesis of the structure with other parts of the area between the sava we 3 m fig. 7 overturned limbs of the fold composed of the upper cretaceous clayey limestones. fig. 8 domino structures formed by layer-parallel slip. 92 geologia croatica 57/1 93jamičić: the “orešje” laramian structure in the ne part of medvednica mt... and drava rivers, it can be concluded that the structure was formed during the laramian movements within the alpine orogeny. the structure is oriented n–s, with e vergence and was formed by the influence of the tangential stress oriented e–w. similarly, almost the same structural forms, as mentioned in the introduction, could be found in the wider region of the croatian part of the pannonian basin. therefore these data should be taken into consideration for interpretation of the tectonic evolution of this part of the pannonian basin. the youngest tectonic movements (tertiary–quaternary), caused by the n–s oriented stress, reshaped parts of the orešje structure. they folded the discontinuity planes and inclined the structural axes along the e–w direction by approximately 10º. based on the recent investigations these events corresponded to the transpression model (jamičić, 1995a) under the influence of left (strike-slip) faults, when the separated blocks were moved apart and counter-clockwise rotated for 35–40° (jamičić, 1981, 1988; márton et al., 1999, 2002). finally, it is important to conclude that medvednica mt. belongs to the pannonian area, and that its tectonic evolution cannot be separated from the evolution of the other mountains of the area. 5. references basch, o. (1983): osnovna geološka karta sfrj 1:100.000. tumač za list ivanić grad, l33–81 (basic geological map of sfry, 1:100,000. geology of ivanić grad sheet).– geol. zavod zagreb, savezni geološki zavod beograd. foetterle, f. (1861/62): geologische karte von kroatien [geological map of croatia – in german].– jahrb. geol. reichsanst., 12/1 (verh. 123–124), wien. gorjanović-kramberger, d. (1908): geologijska prijegledna karta kraljevine hrvatske i slavonije, zagreb, zone 22, col. xiv, 1:75.000 [overview geological map of the croatian and slavonian kingdom – in croatian].– izd. geol. povj. u zagrebu, zagreb. jamičić, d. (1981): izvještaj o geološkom kartiranju za osnovnu geološku kartu sfrj na listu daruvar–106 u 1979. god. [report on geological mapping for basic geological map of sfry at daruvar sheet in 1979 – in croatian].– geol. vjesnik, 34, 147–150. jamičić, d. (1988): strukturni sklop slavonskih planina (sjeverni psunj, papuk, krndija) [structural pattern of the slavonian mts. (northern psunj, papuk, krndija) – in croatian].– unpublished phd thesis, university of zagreb, 152 p. jamičić, d. (1993): die anwendung der β-diagrame bei uberfalteten strukturen [use of β-diagramme in folded structures – in german].– geologia croatica, 46/2, 281– 290, zagreb. jamičić, d. (1995a): the role of sinistral strike-slip faults ih the formation of the structural fabric of the slavonian mts. (eastern croatia).– geol. croatica, 48/2, 55–60. jamičić, d. (1995b): tektonski događaji u južnom dijelu panonskog područja (sjeverna hrvatska): pregled i interpretacija [tectonical events in the southern part of the pannonian area (northern croatia): a review and an interpretation – in croatian].– in: vlahović, i., velić, i. & šparica, m. (eds.): 1. hrvatski geološki kongres (first croatian geological congress), opatija, 18–21.10.1995., zbornik radova (proceedings), 1, 215– 218, zagreb. jamičić, d. (2000a): laramijski pokreti u području južnog dijela panonskog bazena (the laramian movements in the area of southern parts of the pannonian basin).– in: vlahović, i. & biondić, r. (eds.): 2. hrvatski geološki kongres (second croatian geological congress), cavtat–dubrovnik, 17–20.5.2000., zbornik radova (proceedings), 223–224, zagreb. jamičić, d. (2000b): structural deformations in metamorphic rocks of mt. medvednica (croatia).– nat. croatica, 9/4, 275–296, zagreb. jamičić, d., crnko, j., matičec, d., prtoljan, b. (1985): strukturni elementi laramijskih pokreta u području sulkovca (požeška gora) [structural elements of laramian movements in the area of sulkovac (požeška gora mt.) – in croatian].– geol. vjesnik, 38, 149–154. fig. 9 a fracture system in the hanging wall of the overturned anticline. ns fig. 10 a syncline in the upper cretaceous layers formed by the youngest deformational event. 92 geologia croatica 57/1 93jamičić: the “orešje” laramian structure in the ne part of medvednica mt... korolija, b., fuček, l., oštrić, n. & velić, i. (1995): gornjotrijaski i senonski sedimenti kod donjeg orešja [upper triassic and senonian deposits near donje orešje – in croatian].– in: šikić, k. (ed.):geološki vodič medvednice. institut za geološka istraživanja & inaindustrija nafte d.d., 173–179. márton, e., pavelić, d., tomljenović, b., pamić, j. & márton, p. (1999): first paleomagnetic results on tertiary rocks from the slavonian mountains in the southern pannonian basin, croatia.– geol. carpathica, 50, 273–279. márton, e., pavelić, d., tomljenović, b., avanić, r., pamić, j. & márton, p (2002): in the wake of a counterclockwise rotating adriatic microplate: neogene paleomagnetic results from northern croatia.– geol. rundsch., 91, 514–523. polšak, a., nedela-devidé, d., turnšek, d., gušić, i. & benić, j. (1978): biostratigrafski odnosi grebenskih, prigrebenskih i bazenskih naslaga gornje krede u području donjeg orešja, si medvednica [biostratigraphic relationship of reefal, peri-reefal and basinal upper cretaceous deposits in the area of donje orešje, ne medvednica mt. – in croatian].– geol. vjesnik, 30/1, 189–197. manuscript received january 27, 2003. revised manuscript accepted may 04, 2004. 94 geologia croatica 57/1 geol. croat. zagreb 1998 first evidence of hercynian lower carboniferous flyschoid deep-water sediments in the lycian nappes, southwestern turkey he inz w. kozur ', mustafa senel' and kagan tekin' key words: tavas nappe, lycian nappes, lower car­ boniferous, inci rbeleni fonnation, deep-water sedi­ ments, turbidite-olistostrome sequence, hercyni an orogeny. abstract for the first time. a deep-water lower carbon iferous siliciclastic turbidite-olistostrome unit with many iydites (partly di sta lly tur­ bid itic) can be dated in the incirbelcni fonnation o f the tavas nappe (lyeian nappes) in southwestern turkey. these nappes belong 10 a ~outhcrn hercynian upper devon ian to lower carboniferous nysch belt that is also known from the karaburun zone in western turkey. a co nodon t fauna, co nsist in g mainly of gnatllodlls bililleatlls and rcw lochrica coiii/iiii/a/a without nodose lochriea species all ows the :iatin g of chcrl)' limestonc olistoliths as middle to carly late visean .lgc (v isean 2 10 lower vi sel.u1 3) . the lower carboniferous hercyn­ ian deep-sea turbidites and olistostromes confirm a northern origin for .he lycian nappes and a minimum norlh-soulh nappe transport of ipproximatly 200 km. nevertheless. the tavas nappe originatcd to he so uth of the izmirankara zonc because the op hi ol ites of the izmir ankara zonc fo llow in nappe posi tion above the tavas nappe. 1. introduction according 10 goror el al. (1997) who expressed he prcvailing view, only the istanbul block and parts )f the sakarya zone in northwestern turkey had a her­ ;ynian history. south or the istanbul block, the palaco­ ethys is assumed in part s of the sakarya zonc, and its jpper triassic to middlc jurass ic southward directed iubduction is regarded as the reason for the upper tri­ issic opening of neote th ys wi thin the marginal part of }ondwana (~engor , 1984, 1985). the main neotelhyan suture zone is assumed in the zmir-ankara belt. south or this suture zone, from the (araburul1 zone in the north to thc bcydagjari auto­ 'i1thon in thc soulh, the silurian to latc palaeozoic his­ ory was believed to be that of a shallow shelf on the torthcrn part of gondwana. this view was streng th ­ ned by thc fact that silurian 10 permian deep-water edimenl s could not be found or not be dated in th is rca , whereas shallow walei' deposits of th is age are rczso u. r3, h-i029 oudapest . hungary. maden tctkik vc mallia gencl mlidlirlligo. jcotoji ewcheri dairesi, e~ki~chir yoiii, 06520 ankara, turkcy. known, especially from the middle carboniferous to pemlian, but partly also from the silurian to lower car­ boniferous. this general palaeozoic development was assumed also for the tavas nappe or the lycian nappes in the study area, where shallow-water, partly lagoonal and continental development continued in the triass ic (grac1ansky, 1968, 1972; erakman et ai., 1982; ~enel el ai., 1994). new results since 1995 question the previously gen­ erall y accepted view of the silurian to pennian shallow­ water gondwana shelf dcvelopment that reached north­ wards beyond the ncotethyan suture zone (izmir ­ ankara belt). kaya & kozur (1995) discovercd for the first lime pelagic conodonts in the devonian of the karaburun zone and kozur (j 997a, e , d, in prcss) daled the karareis " fonnation" sensu erdogan el al. (1990, 1995) by conodonts, muellerisphacrida and radiolaria as silurian to early carboniferous. the rocks can be subdivided according 10 kozur (op. eit. ) inlo a silurian oceanic sequence of shales and iyditcs and mafi c volcanics, a late caledonian uppe r silurian to pragian nysehoid siliciclastic turbidite-olistostrome unit with distal turbidilic lydites, an upper devonian lime­ stone, shale and chert sequence, an upper famennian to lower visean hercynian turbidite-olistostromc unit , and an upper visean transitional sequence (rich in ammono­ ids, brachiopods, crinoids, trilobites, conodonts, ostra­ cods, radiolarians) to the molasse type shallow-water serpukhovian-bashkirian alandere formation. the transitional sequence contains subduction related fel sic to intermediate luffs. visean rocks of the trans itional sequence werc found al so by cartdrolt el a l. (1997), they contai n the same ross ils but wcre misiden­ tified as upper tournaisian , and assumed to be blocks in the "triass ic" karareis "format ion". thick, very low­ grade metamorphic silici clastic rocks were tentatively assigned without fossil evidence to ihe ordovician (kozur, 1997a, d). in the bolkardag zone, a flyscho id siliciclast ic tur­ bidite-oli stostrome unit wi th dista l turbiditic lydites and fel sic tuffs was reported and assigned to ihe early car­ boniferous by ozcan et a!. ( 1988). 11 was subsequenl· 1y subdivided and daled by goncooglu & kozur (in press) as a llandovery-wenloc k deep-sea shale­ chert sequence with turfs, and a latc caledonian upper silurian to pragian flyschoid sequence. thus, the cale16 danian development is identical both in the karaburun and bolkardag zones. a hercynian deep-water sequ­ ence could not be daled in the bolkardag unit (not prc­ sent?), where carboniferous shallow water rocks (main­ ly limestones) are present. ddrr et al. (1995) reported a s imilar , but me tamorphic sequence from the me n­ deres massif. according to these authors, an (?)early carboniferous flyschoid series overlies black quartzites (? metamorphic lydites) and bas ic volcanics, but this dating is not foss il -proven because of its metamorphic overprint. there fore, a hercynian deep water develop­ ment can be neith er proven nor excluded in the men­ deres mass if. a very interest ing lower carboniferous deep water sequence of similar tectonic position to the tavas nappe is known from the lower nohutluk formation, of the <;:ataloturan nappe of the aladag mountains, at the western end of the easte rn taurus belt. lower car­ boniferous radiolarian-rich turbiditic cherty limestones and rare mudstones are overlain by shallow water lime­ stones and sandstones (upper nohutluk formation) of middle visean to bashkirian age (tekeli et ai., 1984). the nohutluk fomation is unconformably overlain by the shallow water permian arka99a formation which is overlain by variegated shallow water limestones, mud­ stones, marl s and dolomites of triassic age. the che rty limestone olistoliths in the s ilic ic lastic deep-sea tur­ bidites and radiolarites of the incirbeleni formation of the tavas nappe are similar to the cherty limestones of the lower nohutluk formation that yielded, however, a slightly older tournaisian lower visean foraminiferal assem blage (tekeli et ai. , 1984). as these forami ­ ni fe rs are shallow water species, they may have been redeposited in the ca lciturbidites. alternatively, the upper range of thi s foraminiferal fauna may be visean 2 . conodont and radiolarian data from the lower nohut­ lar formation are not available. immediately north of the stable gondwana, a con­ tinuous serpukhovian to lower triassic (and younger) deep-water trough was found extending from crete to western sicily (kozur & krahl, 1987; cata­ lano et ai., 1991; kozur, 1989, 1993) and further to the east in ne iraq and oman (bechennec et ai., 1989; vasicek & kullmann, 1988) which should be also present at leas t in se-turkey . this southe rn deep-sea trough had, during the permian, no connection with the karakaya zone of nw -turkey as the dora­ sham ian radiolarian faunas of sicily and the karakaya complex are totally different (kozur, 1993 , 1997b). moreover, the karakaya ocean opened only in the lat­ est permian (kozur & kay a, 1994 ; kozur , 1997b). opinions concerning a cont inuous middle car­ boni ferous to permian oceanic trough are based on the strat igraphic mis interpretation of red dorashamian radi ­ olarites as art inskian to sakmarian by okay & mos­ tler (1994), as shown by kozur (1997b); the oldest · pe rmian pelagic sediments (pelag ic limestones) of the karakaya zone arc of latest dzhulfian age (kozur & kaya , 1994). geologia croa!ica 5111 thus, both the presence of hercynian flysch with iydites and other deep-water sediments, and (further in the south) the presence of permian tethyan deep water sediments should be expected in southern turkey. bedded iydites (black radiolarites) of late permian age were reported from the radiolarite-rich, s ilic ic lastic turbidite-olistostrome deep-water sequence of the incir­ beleni formation of the tavas nappe, at the ni~angah tepe locality close to the yayla agiliovasi (erak­ man et ai. , 1982; ~enel et ai., 1994; ~enel, 1997). these radiolarites and cherty limestone olistoliths from the si liciclastic turbidite-olistostrome of the incirbeleni formation were investigated. the deep-water character of this flyschoid sequence could be confirmed . how­ ever, the age of this sequence was proven by conodonts to be early carboniferous. 2, location the investigated section northwest of te ke pe nin ­ sula (western taurides) lies in a rather remote area in sw turkey between fethiye and <;:amel i, but east of the road that connects these two towns. the investigated outcrop is sw of the ni ~angah hill (fig. 1). 1000 m w of the sampled outcrop there are a few summer houses for shepherds, and this place is named by the shepherds as the agiliovasi yayla. lydites and cherty limestone olistoliths of a s ilicic lastic turbidite-olistostrome sequ­ ence with many lydites were sampled from the incirbe­ leni formation, which had been assigned according to fusulinid faunas from assumed unde rand overl y ing formations 10 the murgabian (erakman et ai., 1982; ~enel et ai., 1994), corresponding to the lower-middle wordian of the international stage subdiv ision. 3, geological setting the tavas nappe is the lowermost nappe of the lycian nappes. it is tectonically underlain by the ye~il­ barak nappe which consists of two structural units, the gbmbe and yavuz units . the lowe r s tructural unit (gombe unit) is represented by upper cretaceous lime­ stones (gebeler fm. ) and upper lutetian-burdigalian sandstones and shales (elm ali fm.). the upper st ructur­ al unit (yavuz unit) consists of an uppe r lutetian to priabonian fl ysch. the ye~i1barak nappe, in turn, rests tectonically on the beydaglari autochthon consist ing of the cretaceous beydaglari formation, the upper palaeocene-middle eocene di~ ita~tepe fonnation, and the lower miocene sinek~i formation. according to erakman et al. (1982) and ~enel et al. (1994), the tavas nappe is subdivided into the karadag unit of tectonically lower position, tectoni ­ cally overlain by the tekedere unit. the karadag unit consists of the fo llowing forma ­ tions (from the bottom to the top): sazak formation (?upper devonian shal es, lime­ stones), r..u l;u r, ,,)cnci ix i et.:ll1: ! ' irs ! ~vlacnce 01 11crcyn ian lower cnrboniferous fqyschoid, .. 17 a b mediterranean sea nisanoih t. 2'\. 1000m * 8 0 7 r:-:-:-l 6 l.:..:..:..:.i _5 g4 ~3 ~2 .' fi g, i location map. rectang les: positio n of the study area within turkey (a) and , illore detailed. wit hin southwestern turkey (8). detailed illap of the locati on in the ri gh!. legend: j) karadag unit consis ti ng in the s tud y area of kiloluk . akkavak. sar i ta~. karapi nar and bejcnkavak formations: 2) tckedere unit eonsisl ing of <;atakdere. incirbelcni and nit'<1.ngahtcpe formations; horizonlally hatched area: main occurrence of bedded chel'l s and some limestone oii stoiith s, narrow stripe in the ne are iimeslo ncs; 3) <;cnger fonnution; 4) aga<; li forma· tion; 5) serpentinite (marmaris ophiolite nappe); 6) pliocene <;ameji formation (lacustrine depos its); 7) quaternary; 8) sampling poi nt. kiloluk formation (m idd le carbon iferous bioclastic limestones, dolomites, dolomitic limestones), akkavak formation (lower permian crystalline lime­ stones, dolomites, shales), sarita~ formation (?upper anisian to lower ladinian sands tones), karapinar formation (ladinian black limestone), belenkavak formation (carnian-norian sandstones, siltstones, shales). the tekedere unit is thrust over the karadag unit. the thrust boundary is sti ll preserved in the southwest­ ern corner of the study area (fig. i), but often masked by later block fau lting (e.g., in the western part of the investi gated area, where the block with the karadag unit is relatively elevated (+) against the tekedere unit (-) , as shown in fig. i). acco rding to ~enel et al. (1994) and ~enel ( 1997), the tekedere unit consists of the following for­ mations (from the bottom to the top): (:atakdere formation (crystalline limestones), incirbeleni formation (shales, sandstones, limestone " lenses", iydites, volcanics) , and the ni§angahtepc formation (dolomites, limestones). the <;atakdere formation contains, according to ~enel ( 1997), the following fossils (algae and forami­ nifers): mizzia velebitana (schub ert), globivalvl/li­ na vanderschmitti reichel, hemigordius rellzii rei­ c hel, neosehwagerina aatiel/ii/era schubert, pachyph/oia sp., staffel/a sp., and neo/l/sl/lina sp. the ni§angahtepe fonnation contains the followin g fo ssils: mtzzia velebitano (schubert) , colalliel/a sp., geinitzina sp. , globivalvulina /vaeca reichel, hemigordius renzii reichel, neoschwagerina sp .• and paehyph/oio sp. (~enel, 1997). both formations were assigned to the murgabian (= lower-m iddle wor­ dian). they were deposited in a shallow shelf environ­ ment. the incirbeleni fonnation was assumed to be si tua­ ted in normal stratigraphic order between these two for­ mat ions (~enel et ai. , 1994). as it has not yie lded any fossi ls , thi s formation was also ass igned to the mur­ gab ian (erakman et ai. , 1982; ~enel et ai. , 1994; ~enel, 1997). ~enel ( 1997) did not exclude a car­ boniferous age. thi s, however, wou ld excl ude a posi­ tion of the incirbeleni formation between the <;atakdere and ni§angahtepe formations. the placement of the incirbeleni fonnation between two stable carbonate plat form success ions of the same age was not logical for sedimentological-facial reasons. the incirbeleni formation is composed of mafi c vol18 canies, pa rtl y pillow lavas, overlain by shales, bedded iyditcs and clast ics of turbiditic character (graded sha­ les, siltstones, sandstones, in the upper pari also micro­ conglomerates and quartzi lic sandstones). moreover, it also contains limestone olistoli ths. this sequence does not fit into a co ntemporaneous carbonate platform sequence. our d iscovery of lower carboniferous conodonts in the inc irbc le ni formation definite ly excludes it from the ass um ed sequence <;atakdere formation lnc irbc­ lcni format ion ni§angahtcpe formation. there arc two possible ex planat ions for the present juxtaposi tion: ( i) the inc irbe lcni format ion on one s ide and the gatak­ clerc formati on & ni~angahtepe formation on the other s ide be long to d iffe re nt units, tectonically juxtaposed to each o the r. (2) the <;;atakdere formation and the ni§an­ gahtepe formation are parts of the o ri ginal cover beds of the deep-sea inc irbeleni formati on that was late r partly tectonica ll y s liced into thesc carbonate platform rocks. the tecton ic emplacement of the incirbe leni forma­ tion is a lso ind icated by the fact that it is accompanied by an adjaccnt me lange zone. this zone contains be ige q uart zites, iydites, reddish radiola rites and red lim e­ stones with volcan ics. we have not yet inves tigated the age or these rocks. afte r a lengthy hiatus, the rhaetian to lowe r liassic ge nge i' formation iran sg ress ively ove rlies diffe re nt o lder units of the tavas nappe. the <;enge r formation cons is ts o f a bauxite layer, reddi sh cong lome rates, sandstones and s ilts tones (monod e t ai. , 1983 . it is fo ll owed by the liass ic aga~ l i format ion (dolomites and algal limestones) and the upper toarc ian to maas­ trichtian babadag form ation (chert y limes tones, at the base uppe r toarc ian ammon iti co rosso). afte r an unconformity, the re is an upper palaeocene to lower miocene flysch wi th some alka li basalts. we could not find in the fi e ld ev idence that the (engel' formation is scaling an early c immerian overthrust of the tekedcre unit on the karadag uni t. the tec tonicall y h igher nappes of the lycian nappe system (bodrull1 nappe, dumanlidag nappe, mannaris ophiolite nappe, giilbahar nappe, and domuzdag nap­ pe in ascending orde r) are in the study area on ly repre­ sented by serpentinites of the marmaris ophiolite nap­ pe (fig. i). the pliocene gamel i fo rmation cove rs d iffe re nt units o f the t avas nappe and the marmari s ophi o lite nappe. it consis ts of lacustrine deposits. 4. results on ly the ine irbe le ni formation was inves ti ga ted , both the chert y limestone olistoliths and the iyd ites. the conodo nt fauna o f the cherty limestone o li sto lith s is ri ch in spec imens but consists only of two de tenninable spec ies presented by the diagnostic pa elements and by the other c lements of the apparatus. the faun a is dom iw nated by gliolllodus bilinealus (roundy) (pi. i , figs. geo logia cro:l l icfl 51/ 1 1-3), whe reas lochriea commllfafa (b ra nson & mehl) (pi. j, fig. 4) is rare . meisc hner ( 1970) rec­ ognized that such a fauna occurs in the middle visean (v 2 and lower v 3). be low this level, g. biliuealus is not present. both species range up to the lower namuri ­ an. however, in the upper visean (upper v 3) and low­ er namurian (serpukhovian) , they are accompanied by lochriea species that displaces nodes or ri bs on the cup o f the pa eleme nt, such as l. crllcljormis (cla rke), l. 11i01101l0dosa (r hodes , austin & druce), l. i1iullillodosa (wirth), l. l1io llocoslalo (pazukhin & nemirovs ka y a) , l. 1i0doso (b isc hoff), l. sellckellbergica nemirovska y a, perret & mei­ sc i-lner, and l. zieg leri nem iro vskaya, per­ ret & meischner (e.g. mejsc hner , 1970; hig­ gins, 1974; higgins & wagner-gentis, 1982; riley, 1993; skompski e t a i. , 1995). moreover, in th is level , also different subspecies of gj/{jfhoc/us g irlyi /-l ass occur , such as g . girly i girly i hass, g. girlyi col/il1sol1i rhodes , a ustin & druce, g. girlyi ill lerlll edius globensky , g gir lyi rhodesi hig­ g ins, g. girly i simplex dunn, and g. girfyi sol/iae rhodes, austin & dr uce (higg ins , 1975). none of these species were fou nd in the limestone olis toliths of the incirbeleni formation. the absence of g. girfy i m ay be caused by the g reat wate r d ep th or prov incialism, because this species is also not present in the very rich upper visean deep-wate r conodont faunas o r the karaburun peninsula, but lochriea species with sculptu red cup are ve ry common in the uppe r visean of the karaburun pe ninsula (kozu r, 1997a , e, d). the re­ fore , a middle visean (v 2 and early v 3) age for the limes tone olistol iths is ind icated. the iyd itcs arc very rich in radiola rians, but unfo r­ tunate ly , they could not be di ssolved from the rocks. conodonts are rare in the iydites and are only represen t­ ed by indeterminable broke n forms . an exact age deter~ mination is impossible for radiolarians that are enclosed in the rock. however, there we re no rccogn ized form s charac te ristic for beds younger th an ea rl y carbonife r­ ous. o lde r ages can be ne ither exc luded nor provcn for a part of the lydites. s. conclusions i. the sequence of the inc irbe leni formation of (he tavas nappe (lycian nappes) is the sollthernmost dis­ covered hercynian oceanic to suboceanic seque nce in turkey. it consis ts of mafic volcanics and pillow lavas, overl ain by sha les and bedded radiolarites (ma in ly iydi tes), de posited be low the ccd, overlai n by s ili ci­ c lastic turbid ites, o li stoslromes, turbid iti c sandstones, grcywaekes and mierocongiome rates. 2. the southernmost prev iously known occurre nce of hercyni an deep~wa t e r sequcnces th a t e nded in the uppermost early carboniferous, and we re mostly over­ lain by serpukhovian to middle carboni fe rous shallow­ wate r deposits (by this a pal aeo tethyan o rig in can be l\.ozur, .")cilci &: i ckm: 1 ' l r~ 1 i:vl(lcnce 0 1 t lercyn lan l ower c" rtlonirerou ~ flyschoid ... 19 exc luded ), is in the karaburun zone (kozur, 1997a, c) . the incirbeleni formati on is litholog ically ve ry similar to the hercynian sili c iclastic turbidite-oli s­ tostrome unit of the karaburun zone. 11 may originally have bee n a part o f this zone, de ri vatio n from areas o rig ina ll y to the south is not poss ible because the re a gondwana shallow-wate r she lf was present in hercyn­ ian time, thi s proves a northe rn ori g in for the lyc ian nappes, and requ ires a minimum no rth-south nappe tran sport of about 200 km. the lower carbonife rous hercy ni an deep-sea turbidit cs and oli stostromes con ­ finn a northern origin of the lycian nappes and a mini­ mum no rth-south nappe transport o f about 200 km. however, the t avas nappe originated somewhat south of the izmir ankara zone because the ophiolites of the izmir -a nkara zone follow in nappe position immedi ­ ate ly above the tavas nappe. the lower nohutlllk fo rm ation of thc c;atalo!uran nappe in the aladag mountains probably represcnts the outc r she lf-s lope of the southe rn hercyni an ocean , at the transiton to the lower carbon iferous peri gondwana carbonate platform. 3. the olistoliths o f cherty limestones contain a con­ odont fauna of visean 2 lower visean 3. the bedded iydites havc a radiolarian fauna not younger than earl y carbonife rous, as most of the thicke r bedded cherts (mostly lydites) are not ye t dated , a pre-carbon iferous age ca nno t be excluded for parts of the deep-wate r sequcnce. 4. probab le overlying beds (un investigated) of the tekede re unit consis t of molasse type c rinoidal lime­ stones, sandstones, vol canics, volcanic conglomerates that were probably originally overlain by platform car­ bonates with middle permian (guadalupian) fusulinid s « atakdere and ni §angahtepe fomlations), s, if the cora ls o f the sazak formation of the karadag unit are correctly de termined and give a late dev oni an age , as so far assumed (e .g. ~enel, 1997), then the tavas nappe would consis t o f two basicall y diffe rent nappes, one for the karadag unit with a typi ­ ~al devonian -carboniferous shallow-water gondwana she lf deve lopment , and a sccond nappe with the her­ :::ynian deep-wate r developmelll , overlain by a molasse lype and carbonat e p lat form shallow water deve lop­ me nt o f (?)midd le carbon ife rou s to middle permi an ige. acknowledgements the inves ti gatio ns by h,w. kozur were carri ed lut in the fram e of a nato c p grant (tubitak). prof. =. goncuoglu , ankara, discussed many problems md gave a good introducti on to the pal aeozoic his tory )f turkey. prof. dr. a. ramoys , ljubljana, and prof. jr. h. mostler , inn sbruek, improved the pape r by 'ery care ful rev iewing . many thanks are extended fo r his fin anc ial and scientific support. 6. references bechennec, f., le m etour, 1., rabu, d. , beu­ rrier, m. , bourdlllon de grissac, e. , de weyer , 1', beurr1er, m. & yilley , m. (1989): the hawashina nappes : stratigraphy, paleo­ geography and structural evolution of a fragment of the south-te thyan passive continental margin, in: robertson, a.h.f., sear le, m.p. & ries , e. a. (cds.): the geology and tectonics of the oman region, special publications of the geologica l soci­ e ty of london , 49, 21 3-223, london. caridroit, m , degardin, 1.m. , derycke, e. , lethiers , f., marcoux, f. , milt-iau , b., pilleyu it, a. & y achard, d. ( 1997): un ass­ e mblage mic rofaun istiqlle remarqu able du paleo­ zoique supe ri eur de turquie (radiolaires, conodo­ ni cs, ostracodes, foraminiferes, mic rorestes de ver­ tebrates).geobios, 20 , 109115. catalano, r., di stefano, p. & koz ur , h. (1991): permian circumpacific deep-water fa unas from the western te thys (sicily , italy) new evi­ dences for the pos ition of the pe rmian t e thys.­ palaeogeogr. , palaeoelimatol., palaeoecol. , 87( 1-4), 75 108. durr , s. , dora , 0.0. , candan, 0. , ozer, s. & gungor , t. ( 1995): stratigraphy and tecton ics of th e menderes massif. excursion guide, iesca 1995, 1-26, lzm ir. erakman, b., me~hur , m., gul, m.a., alkan, h., ozta~ , y. & akpinar, m., (1982): fethiye· koycegiz-tc fenni-elmali-kalkan arasinda kalan a lanin jeoloj is.sixth turkish. petrol. cong., 23-31 , ankara, erdogan, b., altiner, d., gungor, t. & oz­ er , s. (1990): strat igraphy of karaburun peninsu· la. mineral res. expl. bull. , 111 , 1-20, ankara. erdogan, b., gungor, t., ozer, s., & al tin­ er, d. (1995): stratigraphy and deformational style of karaburul1 belt and i zmir~ankara zone.excur­ sion guide, iesca 1995, 1-31 , izmir. goncuoglu , m.e. & kozur, h. (i n press): facial deve lopment and the rmal alteration of si luri an rocks in turkey,proc. 4. intern, silurian meeting, field meeting spain. gorur , n. , monod , 0. , oka y, a.g. , ~engor , a.m.e. , tuysuz, 0., yigitba~ , e. , sak in<;:, m. & akkok, r. (1997): paleogeograph ic and tec­ ionic position of the ca rboni fe rou s rocks in the wes te rn po ntidcs (turkey) in the fram e of the variscan belt. bull. soc. geol. france , 168-2, 197205. graciansky , p.e. (1968): teke yarimadasi (likya) toros lar ' inin lis l iisle gelmi ~ linite lerinin s trati20 grafisi vc dinaro toroslari 'ndaki yeri. mta de r. , 7 1, 73-92, ankara. graciansky , p.e. (1972): recherches geologiques dans ie taurus lyc ien occidenta l. unpubl. phd thesis, univ. paris sud, ccnter d' orsay, 73 1 p. higgins, a. (1974): conodont zonation of the lower carboniferous of spain and portugal.belgian geol. surv. intern. symposium on be lgian micropaleon­ tological lim its, namur 1974, publ. 4, 1-17, brus­ sels. hi ggins, a. ( 1975): conodont zonation of the late visean -early westphali an stra ta of the south and central pennines of northern england. bull. geol. soc. great britain, 53, 90 p. higgins, a.c. & w agner-gentis, e.h.t. (1982): conodon ts, goniatites and biostratigraphy of the earlier carboniferou s from the cantabrian moun­ tains, spain .palaeontology, 25/2, 313-350, lon­ don. ka y a, o. & kozur , h. (1995): olistostromal aspect of the pre-late cretaceous clastic assemblage in the northern part of the karaburun peninsul a (weste rn turkey).in: international earth science colloqui­ um on the aegean region 1995, program and abstracts, 29, izmir. kozur , h. ( 1989): unter-, mittelund oberpemlische pc lag ischc z irkumpazifi sche ti e fwasserfaunen in w estsizili en und ih re palaogeographi schc bedeu­ tung.50. jahrestagu ng pahiontologischc gesell ­ schaft. prog ramm , zusammenfass ungen, te ilneh­ mer, 5 1, bonn. kozu r, h. ( 1993): upper permian radiolarians from the sosio valley area, western sicily (italy) and fro m the uppermost lamar limestone o f we st texas.jb. geol. b.-a., 136/1 , 99123. kozur, h. (1997a): new stratigraphic results on the pal eozoic of the western parts of the k araburun peninsula, western turkey.in : pi~kin, 0, erg­ on, m., sava~c in, m.y. & tarcan, g. (eds.): proc. international earth sc iences colloquium on the aegean region , iesca 1995, 1,289-307, izmir. kozu r, h. ( 1997b): pelagic permian and tri assic of the weste rn tethys and its paleogeographic and stratigraphic significancc. in: kolloquium i: strati ­ graphic, sedimentation und bcckcnentwicklung im karbon li nd perm , abstracts der vort riige, 48. berg­ und hiittenmiinnischer tag, 2 1-25, freiberg. kozur, h. ( 1997c) : firs t di scovery of muelleri sph ­ aerida (inc. sed is) and eoa/baillella (radi olari a) in turkey and the age o f the s il ic iclastic sequence (c lastic series) in karaburun peninsula. frei berger forseh. -h., c 466, 33-59. kozu r, h. (1997d): late paleozoic and early meso­ zo ic openi ng o f tet hyan oceanic and continental geologia croatica 51/1 basins in turkey.interrad viii, abstracts, 77, paris. kozur , h. (in press): the age of the siliciclastic series ("karare is formation") o f the western karaburun peninsula, western turkey. in : szania wski, h. (cd.): proceedings of the vi european conodont symposium ecos vi, palaeont. poloniea, 58, warszawa. kozur , h. & kaya, o. (1994): first evidence of pelagic late permian conodont s from nw turkey.­ n. jb. geol. paliionl. mh. , 1994/6, 339-347 . kozur , h. & krahl, j. ( 1987): erster nach weis von radiolarien im tethyalen perm europas.n. jb. gcol. pal'ont. , abh., 174/3,357-372. meischner, d. (1 970): conodonten-chronologie des deutsehen karbons.e.r. congr. intern. stra l. gool. carbonif. , sheffield 1967, 11691 180, shef­ field. monod, 0 ., me~hur, m. , martin, m. & lys, m. (1983) : decouverte de dipneustes triasiqucs (cera­ todontiformes, dipnoi) dans ie formation de <;:enger (arkoses rollges) du taurus lycien (turquie occ i­ dentale).geobios, 16/2 , 161 -168. okay , a.i. & mostler, h. ( 1994): carboniferous and permian radio larite blocks from the karakaya com plex in northwest turkey. tr. j. earth sc i­ ences, 3, 23-28 , ankara. ozcan, a., goncooglu, m.e., turhan, n., uysa l, ~. , ~entork, k. & i~ik , a. (1988): late paleozoic evolution of the kiihtahya-bolkardag belt. metu journ . pure app l. sci. , 2 1/1 -3, 21 1220, ankara. riley, n.j . (1993): dinantian (lower carboniferous) biostratigraphy and chronostratigraphy in the british isles .journ . geo l. soc. london , 150, 427-446, belfast. ~enel, m. (1 997): i: 100000 ol<;ekli, tii rkiye jeoloji haritalari serisi , no. 2 : fe lhiye ls.paftas i, an­ kara, 30 p. ~enel, m. , akden iz, n., oztork, e. m., ozde­ mir, t. , kadinkiz, g. , metln, y., ocal, h. , serdaroglu, m. & or<;:en, s. (1 994): fethiye (mugla) kalkan (antalya) ve kuzeyinin jeolojisi.­ mta rep. no. 976 1 (unpublishcd). ~engor , a.m.e. ( 1984): the cimmeride orogenic system and the tectonics of euras ia .geo!. soc. amer. , spec. paper, 195,82 p. ~engor , a.m.e. (1985) : die alpiden lind die kim ­ meriden: die verdoppelte geschichte der tethys .­ geol. rundsch. , 74, 181-2 13. skompski, s., alekseev, a. , meischner, d., nemirovska y a, t., perr et, m.f. & v ark­ er, w.j . ( 1995): conodont distribution across the .h""'''' " ... " .... , u<. , .... '"'' • l..r'l.1 l.. l 21 plate i the fi gured material is housed in the geological institute of the innsbruck university. all figured specimens are from sample 96/640, middl e vi sean cherty limestone o listolith w ithin the incirbe leni formati on sw of the ni ~angah hill at agiliovasi yayla, sw turkey. 1-3 gllarhod"s bifilleollls (roundy); fig. i : upper view, x 50, rep.-no. 23297/ili19; fig. 2: obli que lateral­ upper view, x 100, rep.-no 23297/1it-24; fig. 3: upper view of a specimen with broken free blade, x 80 , rep.­ no. 23297/111-20. 4 lochriea commlllora (branson & mehl), upper view, x 100, rep.-no. 23297/111-2 1. 5 glla/hod"s sp. , upper view of a juvenile specimen, x 200, rep.-no. 23297/1ii-22. 22 visean/namurian boundary.couf. forsch.-inst. scckcnberg, 188, 177-209. tekeu, 0., aksa y, a., drgdn, b.m. & 1~ik, a. (1984): geology of the aladag mountains.in: tekeu, o. & goncdoglu, m.e. (eds.): geolo­ gy of the taurlls bell, 143-158, ankara. geologia croalica 51/1 vasicek, z. & kullmann, j. (1988): eine ammo­ noidecn fauna von sosio-typ (guadalupian , ober­ perm) aus kurdistan (iraq).palaeonlograph ica, a, 204/1-3,95-115. manuscript received december 1,1997. revised manuscript accepted may 18, 1998. schafhauser et al.indd 1. introduction in late cretaceous times rudist bivalves became the most important benthic carbonate producers in both the tethyan and caribbean realms (kauffman, 1973; ross & skelton, 1993). they predominantly built widespread monoto paucispecific associations but were also able to co-exist successfully with corals yielding complex and diverse coral–rudist reefs (e.g., kauffman & sohl, 1973; masse & philip, 1981; laviano, 1984; camoin et al., 1988; scott et al., 1990; höfling, 1997; sanders & baron-szabo, 1997; sanders & pons, 1999; depositional environment of coral–rudist associations in the upper cretaceous cardenas formation (central mexico) armin schafhauser1, stefan götz1, rosemarie baron-szabo2 and wolfgang stinnesbeck1 götz, 2001, 2003; mitchell, 2002). the spatial distribution of coral–rudist reefs was mainly controlled by environmental conditions (e.g., sedimentation rate, palaeobathymetry, current regimes, salinity) (gili et al., 1995; gili & skelton, 2000; götz, 2003). like many other taxa, rudists became extinct at or close to the cretaceous/tertiary (k/t) boundary. as a result of the scarcity of outcrops and the poor stratigraphic constraints of rudist associations, the timing and pattern of rudist demise is still controversial (johnson & kauffman, 1996; steuber et al., 2002). the upper cretaceous cardenas formation contains abundant rudist and coral–rudist associations, which belong to the youngest known late cretaceous assemblages worldwide. these assemblages may potentially provide new data about latest cretaceous rudist history (johnson & kauffman, 1996). since the monograph of böse (1906) the diverse faunal assemblages of the cardenas fm. have been studied by several authors (böse & cavins, 1927; burckhardt, 1930; muellerried, 1930; myers, 1968; hurtado-gonzalez, 1984; vega et al., 1995; alencaster et al., 1999; caus et al., 2002). nevertheless, a detailed analysis of these coral–rudist associations is lacking in the literature. herein we present a detailed description of an approximately 170 m thick sequence selected from an approximately 900 m thick section of the cardenas fm. it is exposed in a river bed called the arroyo de la atarjea (myers, 1968), situated approximately 3 km north of the city of cardenas (fig. 1). myers (1968) first described the composition and tectonic structures of the cardenas fm. from this locality. the selected sequence contains one radiolitid assemblage and 23 coral–rudist reefs. subsequently, we use the term “reef” in the general sense of “calcareous deposits created by essentially in place sessile organisms” (riding, 2002, p. 165). 2. geologic setting and lithologies of the cardenas formation the upper cretaceous cardenas formation exposed in central mexico (state of san luis potosí) is a mixed geologia croatica 56/2 187–198 11 figs. 1 tab. zagreb 2003 key words: upper cretaceous, maastrichtian, reefs, corals, rudists. 1 geological institute, university of karlsruhe (th), kaiserstraße 12, 76131 karlsruhe, germany; e-mail: armin.schafhauser@bio-geo.uni-karlsruhe.de 2 department of invertebrate zoology, smithsonian institution, washington, dc 20560, usa abstract in the cardenas formation (central mexico), a 175 m thick sedimentary sequence of maastrichtian age was analyzed with respect to its palaeontology and sedimentology. a wide variety of lithological and palaeontological features characterize this sequence comprising unfossiliferous and fossil-bearing sandand siltstones, and diverse rudist and coral–rudist associations in carbonate or mixed carbonate/ clastic lithologies. a total of 24 rudist and coral–rudist associations are exposed in the investigated section, which are grouped into 5 limestone units. radiolitid assemblages, coral–rudist reefs, coral-dominated reefs, and hippuritid-dominated reefs are present. the stacking pattern of these reef intervals indicates a general transgressive trend through the entire section. smaller-scale facies trends could be distinguished within each limestone unit, comprising deepening-upward sequences, defined by a shoreface–calcareous algae–radiolitid–marl facies transition, and shallowing-upward sequences defined by a hippuritid–actaeonellid–coral/rudist facies transition. this cyclic sedimentation pattern is obscured by an episodic input of clastic sediments derived from the uplifting sierra madre oriental, which in turn triggered either the development or decline of reefs. 188 geologia croatica 56/2 189schafhauser, götz, baron-szabo & stinnesbeck: depositional environment of... clastic–carbonate sedimentary sequence approximately 1800 m in thickness. laterally, the sedimentary rocks of the cardenas fm. pass into the deep water marls of the coeval mendez formation, which in turn overlie marl and limestone units of the san felipe formation (fig. 2) (sohl et al., 1991; vega et al., 1995). the cardenas fm. conformably overlies the uppermost limestone units of the valles–san luis potosí (v. s. l. p.) carbonate platform (tamasopo formation), which are of cenomanian to santonian age (basañez-loyola et al., 1993). the cardenas fm. is overlain by the red beds of the tabaco formation, which are of unknown age (myers, 1968). according to our results, the tabaco fm. consists of sandstones, claystones, and varicoloured conglomerates that conformably overlie the cardenas fm. tectonically the sediments of the tamasopo fm., the cardenas fm., and tabaco fm. are part of the fold and thrust belt of the sierra madre oriental of eastern mexico (torre, 1964; fuentenavarro, 1964; suter, 1987). the sedimentary rocks of the cardenas fm. were deposited during the campanian–maastrichtian time period (myers, 1968; caus et al., 2002), when a facies change from carbonate dominated deposition to mainly clastic sedimentation took place in northern and central mexico (lopez-ramos, 1985; sohl et al., 1991; moran-zenteno, 1994; ye, 1997). in central mexico this facies change is represented by the transition from the limestone units of the v. s. l. p. carbonate platform to the mixed clastic–carbonate sediments of the cardenas fm. and the marls of the mendez fm. (sohl et al., 1991; moran-zenteno et al., 2000; goldhammer & johnson, 2001). the input of clastic sediments during the upper cretaceous may be attributed to early orogenic phases of the sierra madre oriental (sohl et al., 1991; ye, 1997). due to this uplift underlying older sedimentary units of the v. s. l. p. carbonate platform were eroded and deposited as clastic sediments in the foreland basin east of the sierra madre oriental (fig. 3) (ye, 1997). in the cardenas region, the shallow water units of the cardenas fm. were deposited in a narrow depositional area in front of the sierra madre oriental, whereas the mendez fm. represents the deeper parts of the foreland basin farther east. in the tertiary, the main orogenic phases of the sierra madre oriental involved the sediments of the cardenas fm., resulting in their deformation into broad anticlines and synclines (torre, 1964; fuente-navarro, 1964; myers, 1968). myers (1968) subdivided the cardenas fm. into 3 lithological members (fig. 5; for explanation of symbols see fig. 4), which comprise clastic intervals consisting of marls, siltand sandstones as well as conglomeratic layers intercalated in the sandstone beds at the base of the upper member. the lower and upper members are characterized by rudistand coral–rudist limestones, which are absent in the middle member of the cardenas fm. (myers, 1968). 3. lithologies of the investigated section the sediment succession investigated herein is 175 m thick and belongs to the upper member of the cardenas formation. the section is generally well exposed despite a few intervals that are partly covered by soil and calcretes (fig. 6). sedimentary rocks consist of interlayered marls, fine-grained sandstones, oolithic and bioclastic grainstones, and algal packstones. these sediments are described in detail below. in addition, 5 units (u1–u5) with rudist and coral–rudist associations, intercalated with the clastic sediments, are described in the following sections. the age of the section is considered to be maastrichtian, based on the ammonite sphenodiscus pleurisepta (conrad) found in the lower member of the cardenas fm. that is also exposed in the arroyo de la atarjea. in the lower part of the section fine-grained sandstones are predominant and are intercalated with fig. 1 location of the investigated section in the arroyo de la atarjea riverbed (myers, 1968). fig. 2 stratigraphy of the formations of the cardenas area. the marls of the mendez formation interfinger with the mixed clastic–carbonate units of the cardenas formation. the cardenas fm. overlies the shallow water carbonates of the valles–san luis potosí carbonate platform (tamasopo formation). the cardenas fm. is covered by the red beds of the tabaco formation. similar to the marl and limestone units of the san felipe formation, the age range and geologic context of the tabaco fm. is not well defined in central mexico. 188 geologia croatica 56/2 189schafhauser, götz, baron-szabo & stinnesbeck: depositional environment of... 1.5–6 m thick oolithic and bioclastic grainstones. the sandstone beds are between 20 cm and 3 m in thickness and characterized by lamination and cross-bedding. the sandstones are fine-grained calclithites (pettijohn et al., 1984) and consist of more than 50% non-skeletal limestone clasts and abundant quartz clasts. the clasts are subangular to subrounded and well sorted. matrix is absent. generally, the sandstones are nonfossiliferous but two 3.5 cm and 0.5 m thick sandstone layers below unit u1 contain slightly fragmented radiolitids. a bioturbated horizon separates these sandstone layers from the overlying reef. the bioclastic grainstones contain abundant coral, rudist (plagioptychids, radiolitids, hippuritids) and echinoderm fragments, benthic foraminifera (orbitoids, miliolids), dasycladaceans, and red algae as well as abundant non-skeletal carbonates and detrital quartz. the allochems in the oolithic grainstones consist of superficial ooids with a radial microframe and coated grains, which are well rounded and sorted. the nuclei of the ooids are miliolid foraminifera, quartz fragments, and molluscan shells. interstitial spaces of the components are filled by dog-tooth spar cement and blocky calcite cement. the uppermost 10 cm of the oosparite bank are bioturbated. in the upper part of the section (from approximately 15 m below unit u2 to the top) the faunal diversity increases comprising single individuals and clusters (4–5 specimens) of plagioptychids (coralliochama sp.), non-rudist bivalves (e.g., exogyra costata say, pycnodonte mutabilis (morton), lopha sp., trigonia sp., pholadomya sp., cardium sp.), and gastropods (actaeonellids, turritellids). the sandstones are interlayered with 5 cm to 5 m thick beds of sandy marls and one algal packstone bed containing dasycladaceans, miliolid foraminifera, and detrital quartz. between units u2 and u4 the sandstone layers are approximately 5–10 cm thick and interlayered with thin-bedded (5–10 cm) sandy marls. molluscan fragments, benthic foraminifera (orbitoids, miliolids), and dasycladaceans were observed in the sandstones. in the uppermost marl layers abundant ornamented ostracods were found. 4. rudists and corals of the cardenas formation since böse (1906) documented rudist species of the cardenas formation in his monograph, they have been the object of numerous articles (e.g., böse & fig. 3 palaeogeography of the gulf of mexico in the late cretaceous (modified after pindell et al., 1988, and sohl et al., 1991). the mixed clastic–carbonate sediments of the cardenas formation and the marls of the mendez formation were deposited in the foreland basin east of the sierra madre oriental. in southern mexico the rudist-bearing yucatan carbonate platform developed. fig. 4 explanation of lithological and fossil symbols used in the following figures (figs. 5–8, 10, 11). 190 geologia croatica 56/2 191schafhauser, götz, baron-szabo & stinnesbeck: depositional environment of... cavins, 1927; myers, 1968; muellerried, 1930; alencaster et al., 1999; schafhauser et al., 2002). in addition, they are also well-known from the caribbean region (chubb, 1971; mitchell, 2002; steuber, 2002; steuber et al., 2002) as well as from coeval sediments of chiapas in southern mexico (alencaster, 1971) and the yucatan carbonate platform in guatemala (scott, 1995; steuber, 2002). their taxonomy was described in detail by many authors, including böse (1906), myers (1968), and alencaster (1971). in contrast, the coral fauna of the cardenas fm. is nearly unknown. a list of all coral species collected during this field work from several outcrops of the upper member of the cardenas fm. is presented in table 1. 5. rudist associations within the cardenas formation one layer comprising individuals or clusters of radiolitids (r1) and 23 coral–rudist reefs (r2–r24) is exposed in the investigated section of the cardenas formation (figs. 6–8, 10). the reefs are concentrated in 5 limestone units (fig. 6): unit u1 encompasses radiolitid assemblage r1 and coral–rudist reef r2 (fig. 7), unit u2 reefs r3 and r4 (fig. 8), unit u3 reefs r5–r8 (fig. 8), unit u4 reefs r9–r15 (fig. 8), and unit u5 reefs r16–r24 (fig. 10). in general, the number of units and their thickness increase towards the top of the section (fig. 6). within each unit, reef-thickness ranges from 0.5 to 2 m. towards the tops of units u3, u4, and u5 reef thicknesses decrease gradually. the reefs are separated by marls, sandy marls or fine-grained sandstones. generally, the unsorted bioclasts and the well preserved fossils in the reef limestones indicate autochthonous embedding of the coral–rudist reefs. in the following description we group rudist and coral–rudist associations of similar character and distinguish four different types: radiolitid assemblages, mixed coral–rudist reefs, coral-dominated reefs, and hippuritid-dominated reefs. fig. 5 schematic illustration of lithology, lithostratigraphic units and faunal content of the cardenas formation as described by myers (1968) (for explanations of symbols see fig. 4). dictuophyllia conferticostata (vaughan,1899) cladocora jamaicaensis vaughan, 1899 cladocora gracilis (d’orbigny, 1850) antiguastrea cellulosa (duncan, 1863) multicolumnastraea cyathiformis (duncan, 1865) placocoenia major felix, 1903 siderastrea vancouverensis vaughan, 1923 siderastrea adkinsi (wells, 1934) actinhelia elegans (goldfuss, 1826) meandrophyllia oceani (fromentel, 1873) dermosmiliopsis orbignyi alloiteau, 1952 trochoseris catadupensis vaughan, 1899 cyathoseris formosa d’achiardi, 1875 actinacis parvistella oppenheim, 1930 actinacis haueri reuss, 1854 goniopora sp. table 1 coral species collected from the upper member of the cardenas formation. 190 geologia croatica 56/2 191schafhauser, götz, baron-szabo & stinnesbeck: depositional environment of... 5.1. radiolitid assemblages in the investigated section the lowermost rudist-bearing bed (r1) is approximately 1 m thick and contains single specimens or clusters of small radiolitids, which reach maximum heights of approximately 5 cm (fig. 7). the sediment consists of a radiolitid floatstone with packstone matrix that contains rare benthic foraminifera (rotaliidae, miliolidae), coralline algae as well as fragments of echinoderms. the bioclasts are unsorted and angular, suggesting only minor current energy. rudists are not in life position, but parautochthonous embedding is suggested by the low degree of shell fragmentation. 5.2. coral–rudist reefs the majority of the reefs in the cardenas formation are mixed coral–rudist reefs (r2–r4, r6, r7, r10–r14) (figs. 7–8). their thickness ranges from 0.5 to 2 m. upsection, in units u3 and u4, the reefs continuously decrease in thickness. reefs r3 and r4 are laterally exposed. they are lens-shaped biostromes and reach lateral extensions of approximately 14 m. within the units the reefs are separated by marls, sandy marls or fine-grained sandstones. the latter contain abundant actaeonellid gastropods. in unit u3 plagioptychids are also very common. generally, this reef-type contains a diverse coral– rudist fauna. the rudists are dominated by radiolitids (t. floriformis, bournonia cardenasensis (böse), biradiolites sp.) and plagioptychids (coralliochama gboehmi böse, coralliochama sp.), but hippuritids (hippurites muellerriedi trechmann, hippurites ceibarum muellerried) were also observed, which occur in thickets of more than 10 species. the radiolitid tampsia and plagioptychid coralliochama reach maximum heights of approximately 40 cm. hippuritids are up to 15 cm in height. the coral fauna encompasses columnar, massive, and encrusting growth-forms. species comprise abundant multicolumnastraea cyathiformis as well as siderastrea adkinsi, actinhelia elegans, cladocora gracilis, dictuophyllia conferticostata, dermosmiliopsis orbignyi, placocoenia major, actinacis parvistella, and actinacis haueri. in reef r2 a large number of neithea, a non-rudist bivalve, settled onto the corals. the reef fauna of the coral–rudist reefs is generally well preserved and appears in growth position. only in reef r6 and on the top of r2 rudists and branched corals are reworked but still well preserved and unfragmented, thus indicating the absence of significant transport. upsection from the reworked layer of r6, the prior reef fauna is reestablished. in thin sections coralline algae frequently encrust both rudists and corals, whereas hippuritid shells suffered strong bioerosion. clinger morphotypes (skelton & gili, 1991) of plagioptychids build the pioneer fauna at the base of reefs r3 and r4 (fig. 9). they settled in scour marks fig. 6 lithologic succession and fossil content of the investigated section of the cardenas formation. the section contains 5 limestone units illustrated separately in figs. 7, 8, 10. the whole sedimentary succession is interpreted as a transgressive facies sequence that consists of 8 deepening-upward (d1–d8) and 4 shallowing-upward (s1–s4) facies sequences (for explanation of symbols see fig. 4). 192 geologia croatica 56/2 193schafhauser, götz, baron-szabo & stinnesbeck: depositional environment of... that are incised into the underlying sandstones and might have provided a stable substrate for the overlying reef-fauna. reef sediment consists of coral–rudist rudstones with packstone and wackestone matrix that contains unsorted and angular fragments of rudists, corals, gastropods, and non-rudist bivalves as well as detrital quartz. microfossil constituents comprise abundant dasycladaceans, ?gymnocodiaceans, and benthic foraminifera (miliolids and rotaliids) as well as coralline algae and ostracods with articulated valves. in addition, rodoliths are abundant components in the packstones and wackestones of reef r2 and present nuclei of radiolitid and plagioptychid fragments. 5.3. coral-dominated reefs the reefs r17–r24 in the uppermost section (unit u5) are dominated by corals (fig. 10). upsection, reef-thickness decreases from 1–2 m at the base to 15–40 cm at the top. the 9 reefs are separated by layers of marls, which are 1–25 cm in thickness. the number and diversity of rudists in coral-dominated reefs is considerably lower than in the underlying coral–rudist reefs (r1–r16). the rudist fauna consists of radiolitids (biradiolites sp.), plagioptychids, and sparse hippuritids (e.g., h. ?perkinsi). rudists are small and reach up to 10 cm in height. although the diversity of corals is very low, they are the main reef builders. the coral fauna is conspicuously dominated by columnar and ramose growth forms of the species m. cyathiformis and d. conferticostata, but massive growth forms of the species a. cellulosa also occur. numerous specimens of neithea were found on top of the corals and are characteristic components of the coral-dominated reefs. the matrix of the reef bafflestone consists of packstone with abundant miliolid foraminifera, dasycladaceans, and rare fragments of gastropods. abundant ostracods and miliolid foraminifera were found in the interlayered marls. 5.4. hippuritid-dominated reefs reefs r5, r8, r9, r15 and r16 (figs. 8, 10) are between 20 cm and 1 m thick and characterized by the abundance of hippuritids and the absence of radiolitids. 10–15 cm thick marl and sandstone layers separate these hippuritid-dominated reefs from coral–rudist or coral-dominated reefs (figs. 8, 10). the sandstones upsection from reef r5 and below reef r8 contain abundant actaeonellids (fig. 8), whereas a 10 cm thick marl layer overlies reef r16 (fig. 10). except for the absence of radiolitids the faunal composition is similar to the coral–rudist reefs. the rudist fauna is exclusively composed of hippuritids (h. ceibarum, hippurites sp.) and plagioptychids whereas coral species are generally the same as in the coral–rudist reefs. reef sediment is also similar to the fig. 7 detailed illustration of limestone unit u1 (see also fig. 6). the section contains 1 radiolitid assemblage (r1) and 1 mixed coral–rudist reef (r2). the sedimentary succession includes 1 deepening-upward (d1) and 1 shallowing-upward sequence (s1) that are also illustrated in fig. 6 (for explanation of symbols see fig. 4). fig. 8 detailed illustration of units u2–u4, (see also fig. 6). the 3 units contain 9 coral–rudist reefs (r3, r4, r6, r7, r10, r11, r12, r13 and r14) and 4 hippuritid-dominated reefs (r5, r8, r9 and r15), and include 3 deepening-upward (d4–6) and 2 shallowingupward (s2, s3) sequences that are also illustrated in fig. 6 (for explanation of symbols see fig. 4). 192 geologia croatica 56/2 193schafhauser, götz, baron-szabo & stinnesbeck: depositional environment of... coral–rudist reefs, except for the absence of coralline algae and ostracods. 6. depositional environment of the cardenas formation rudist and coral–rudist associations of the cardenas formation developed in areas of low water energy and on soft substrates, indicated by low fragmentation of the fauna and by the angular and unsorted bioclasts in the wackestones and packstones. the abundance of dasycladacean algae and miliolid foraminifera in the sediments suggest rudist and coral growth in lagoonal environments. high-energy events produced reworked layers of rudists and corals (e.g., r2, r6, r17; figs. 7, 8, 10). in the lower part of the section, a high input of terrigenous clastic sediments is indicated by the abundance of sandstone units which prevented the development of extended reefs. only clusters of small radiolitids developed and corals are completely absent. moreover, the radiolitid-bearing sandstone units below the radiolitid assemblage r1 are also devoid of coral fragments. radiolitids might have been able to sustain changes in water chemistry, salinity, and aerial exposure (kauffman & sohl, 1973), thus indicating a nearshore environment for these assemblages, possibly in the upper subtidal area of restricted lagoons. this theory is also supported by the presence of laminated and cross-bedded sandstones below these units which are interpreted as shoreface zone deposits (tucker, 1990a). in the upper part of the section the decreasing number of sandstone units indicates less influence of clastic sediments resulting in the development of abundant diverse mixed coral–rudist reefs (figs. 6, 8). the diverse coral fauna indicates stenohaline conditions and deeper waters than is suggested by the radiolitid assemblage below. nevertheless, the mixed coral–rudist and coral-dominated reefs developed in shallow water environments or even in open lagoons, which is indicated by the presence of abundant miliolid foraminifera and dasycladacean algae. in the coraldominated reefs, the absence of detrital quartz and the predominance of columnar and ramose corals indicate low water energy (chappell, 1980) and reef growth in sheltered lagoonal areas, which were not influenced by the input of clastic sediments (götz, 2001). in the hippuritid-dominated reefs (r5, r8, r9, r15, r16; figs. 7–8, 10) the absence of ostracods and radiolitids suggests that this reef type reflects the deepest environments of all reefs in the investigated section. they correspond to the hippuritid reefs described from the mixed siliciclastic–carbonate units of the gosau basin in austria, where hippuritid-dominated reefs grew on the inner shelf (sanders & baronszabo, 1997; sanders & pons, 1999). also, on the turonian–upper santonian adriatic carbonate platform hippuritid reefs occur in the deeper parts of the outer platform (moro, 1997). the actaeonellidbearing sandstones that are intercalated with the hippuritid-dominated reefs and the mixed coral–rudist fig. 9 clinger morphotypes (skelton & gili, 1991) of plagioptychids build the pioneer fauna at the base of reef r3. they settled in scour marks that are incised into the underlying sandstone units. fig. 10 detailed illustration of limestone unit u5 (see also fig. 6). the unit contains 8 coral–rudist reefs (r17–r24) and 1 hippuritiddominated reef (r16) and includes 1 deepening-upward (d8) and 1 shallowing-upward (s4) sequence that are also illustrated in fig. 6 (for explanation of symbols see fig. 4). 194 geologia croatica 56/2 195schafhauser, götz, baron-szabo & stinnesbeck: depositional environment of... reefs might represent mobile sand bodies that separated the lagoonal from inner shelf environments (sanders & pons, 1999). in the cardenas fm. plagioptychid rudists are not restricted to reefal limestones. they occur in life position with a diverse molluscan fauna in marls and sandstones. the clinger plagioptychids, coralliochama, form a pioneer fauna at the base of the coral–rudist reefs r3 and r4 in scour marks that are incised into the underlying clastic units. plagioptychids also occur within mixed coral–rudist, coral-dominated, and hippuritid reefs. however, radiolitid-assemblages are devoid of plagioptychids. this indicates that plagioptychids tolerated input of terrigenous clastic sediment into their habitat, but on the other hand they were probably less tolerant to changes in salinity and temperature. 7. facies development within the section environments of rudistand coral–rudist associations are similar in the investigated section, but allow definition of 8 deepening (d1–d8) and 4 shallowingupward sequences (s1–s4) (fig. 6). reef thickness decreases in transgressive intervals and increases in regressive sequences (figs. 8, 10). we grouped these facies sequences in 4 idealized sedimentary cycles, comprising 2 deepeningand 2 shallowing-upward cycles (fig. 11). in the section most of the cycles are incomplete. unfortunately, the composition of these idealized cycles is obscured by sandstone units (e.g., d3, d7 – fig. 6). the sand derived from the uplifting sierra madre oriental to the west and was episodically transported into the cardenas area, where these beds are superimposed on the cyclic background sedimentation. the first idealized deepening-upward cycle (fig. 11a) consists of basal cross-bedded and laminated calclithites of the shoreface which pass into lagoonal radiolitid assemblages, that are in turn overlain by oolithic grainstones. the well-rounded and sorted ooids indicate shallow water depths and form oolite bars that were deposited seaward of the lagoons on the inner shelf (tucker, 1990b, c). this cycle type occurs in the lowermost part of the section and is represented by facies sequences d1 and d2 (fig. 6). the sequences are separated from the following cycles by bioturbated horizons. the second type of deepening-upward cycle (fig. 11b) is represented by facies sequences d3–8 (figs. 6, 8, 10) and comprise cross-bedded shoreface calclithites which pass into lagoonal marls or limestones, which contain miliolid foraminifera and dasycladacean algae. upsection they are overlain by coral–rudist associations (coral–rudist, coral-dominated or hippuritid-dominated reefs) passing into thin bedded marls and sandstones, which are rich in gastropods (turritellids), plagioptychids (coralliochama sp.), and non-rudist bivalves. our interpretation is that these interlayered marls and sandstones represent the deepest part of the depositional area and were deposited on the inner shelf indicated by the diverse molluscan fauna, sparse miliolid foraminifera, and the absence of calcareous algae. the abundance of sandstones makes interpretation of facies sequence d3 difficult. limestones containing rudist fragments, miliolid foraminifera, and dasycladacean algae are interpreted as the talus of rudist dominated lagoonal assemblages. the diverse fauna in the uppermost part of the sequence is similar to the inner shelf fauna described above from the deepeningfig. 11 idealized sedimentary cycles observed in the investigated section (fig. 6). frequently, however, these cycles are incompletely developed and obscured by sandstone units (see text). in the right column, facies are marked that occur in the deepeningand shallowing-upward sequences of the investigated section (for explanation of symbols see fig. 4). 194 geologia croatica 56/2 195schafhauser, götz, baron-szabo & stinnesbeck: depositional environment of... upward cycle (fig. 11b). the lack of coral-rudist reefs may be due to the high input of clastic sediments, which was indeed tolerated by the inner shelf fauna comprising gastropods, plagioptychids, and non-rudist bivalves. therefore, we interpret this sequence as a transgressive succession, which passes from lagoonal to inner shelf environments like the idealized deepeningupward cycle of fig. 11b. at its base, the first idealized type of shallowingupward cycle (fig. 11c) consists of hippuritid-dominated reefs from the inner shelf, which are overlain by actaeonellid sand bar deposits. upsection mixed coral–rudist reefs of the inner lagoon follow. the second type of shallowing-upward cycle (fig. 11d) occurs only in the uppermost rudist unit u5 (figs. 6, 10) and differs from the shallowing-upward cycle described above by the lack of sand bar deposits. coral-dominated reefs grew in sheltered areas with less sediment input (see chapter 6): actaeonellid-bearing sand bar deposits are replaced by marls. shallowing-upward cycles commonly terminate in layers containing reworked reef fauna (s2, s4; figs. 8, 10). we interpret these reworked layers as having been derived from reefs situated above the storm wave base, which were therefore subject to erosion. the investigated section of the cardenas fm. consists of interlayered fine-grained sandstones, marls, and limestones. in the lower part of the section, sediments of the shoreface and lagoonal sediments are predominant and are represented by cross-bedded and laminated sandstones, and radiolitid assemblages. in the upper part of the section the number of sandstone units decrease, whereas limestone units are abundant. in addition, units of marl layers occur, which contain a diverse inner shelf fauna, indicating a general deepening-upward trend from the base of the section towards the top. such transgressive phases together with the low sediment input permitted the development of the diverse coral–rudist reefs in the cardenas area. 8. conclusions the investigated section of the upper cardenas formation is of maastrichtian age and comprises a transgressive sequence that consists of sandstones, marls, and limestones. the limestone units contain 4 types of rudist and coral–rudist associations. radiolitid assemblages were deposited in restricted lagoons. mixed coral–rudist and coral-dominated reefs developed in open stenohaline lagoons. reefs dominated by corals are indicative of sheltered areas with less input of clastic sediments. hippuritid-dominated reefs grew seaward of the lagoons on the inner shelf. only plagioptychids occur in both the coral–rudist associations and the clastic sediments of the outer shelf, but are absent in the radiolitid assemblages of restricted lagoons. plagioptychids were able to live in environments strongly influenced by changing sediment input, but were probably less tolerant to salinity or temperature changes of the seawater. the investigated transgressive sequence encompasses several deepeningand shallowing-upward facies sequences, which can be grouped in idealized types of deepeningand shallowing-upward cycles. the deepening-upward cycles pass from cross-bedded sandstones of the shoreface into calcareous algal or radiolitid dominated limestones and marls of restricted lagoons. they are in turn overlain by lagoonal coral–rudist associations and marls of the outer shelf containing diverse molluscan assemblages (gastropods, plagioptychids and non-rudist bivalves). the shallowing-upward cycles consist of basal hippuritid-dominated reefs that pass into actaeonellid sand bar deposits or marls, which are overlain by coral– rudist reefs. this cyclic background sedimentation was obscured by the episodic input of clastic sediments derived from the uplifting sierra madre oriental to the west. this sediment input decreases in the upper part of the transgressive sequence, resulting in an increasing number of coral–rudist reefs. so rudist reefs of the cardenas formation flourished in times of low sediment input during transgressive phases. acknowledgements we gratefully acknowledge the calderon family and josé miguel díaz from cardenas and prof. dr. lopéz oliva from the universidad autónoma de nuevo león for support during field work. we thank stefan unrein and elke herrmann for preparing thin sections and acknowledge the constructive review of this paper by robert w. scott and jose m. pons. we also thank the german academic exchange service (daad) and deutsche forschungsgemeinschaft (project sti 128/7, go 1021/2–1 and ba 1830/3) for financial support. 9. references d’achiardi, a. (1875): coralli eocenici del friuli [eocene corals of friuli – in italian].– atti della societa toscana di scienze naturali resindente in pisa, 1, 67–86. alencaster, g. (1971): rudistas de cretácico superior de chiapas, parte 1 [upper cretaceous rudists from chiapas, part 1 – in spanish].– paleontología mexicana, 34, 1–91. alencaster, g., omaña, l., pons, j.m., torres, j.r., tristan, m. & vazquez, n. (1999): upper cretaceous rudists and larger foraminifera from the cárdenas region, san luis potosí, méxico.– erlanger geologische abhandlungen, 3, 6–7. alloiteau, j. (1952): embranchment de coelentérés. ii. madréporaires post-paleozoiques [branching of 196 geologia croatica 56/2 197schafhauser, götz, baron-szabo & stinnesbeck: depositional environment of... coelenterates. ii. post-paleozoic madrepores – in french].– in: piveteau, j. (ed.): traité de paléontologie. publ. sous la dir. de jean piveteau, 1, 539–684. basañez-loyola, m.a., fernandez-turner, r. & rosales-dominguez, c. (1993): cretaceous platform of valles–san louis potosi, northeastern central mexico.– in: simo, t.j.a., scott, w.r. & masse, j.-p. (eds.): cretaceous carbonate platforms. aapg memoir, 56, 51–59, tulsa. böse, e. (1906): la fauna de moluscos del senoniano de cárdenas, san luis potosí [molluscan fauna of the senonian from cárdenas, san luis potosí – in spanish].– boletín del instituto geológico de méxico, 24, 95 p. böse, e. & cavins, o.a. (1927): the cretaceous and tertiary of southern texas and northern mexico.– university of texas bulletin, 2784, 7–142. burckhardt, c. (1930): etude synthétique sur le mésozoique mexicain [integrated study on the mexican mesozoic – in french].– société paléontologique de suisse memoir, 49–50, 280 p. camoin, g., bernet, r.m.c. & philip, j. (1988): rudist–coral frameworks associated with submarine volcanism in the maastrichtian of the pachino area (sicily).– sedimentology, 35, 123–138. caus, e., tambareau, y., colin, j.-p., aguilar, m., bernaus, j.-m., gomez-garrido, a. & brusset, s. (2002): upper cretaceous microfauna of the cárdenas formation, san luis potosí, ne mexico. biostratigraphical palaeoecological, and palaeogeographical significance.– revista mexicana de ciencias geológicas, 19, 137–144. chappell, j. (1980): coral morphology, diversity and reef growth.– nature, 286, 249–252. chubb, l.j. (1971): rudists of jamaica.– palaeontographica americana, 7, 161–257. duncan, p.m. (1863): on the fossil corals of the west indian islands.– quarterly journal of the geological society of london, 19, 406–458. duncan, p.m. (1865): a notice of the geology of jamaica, especially with reference to the district of clarendon; with descriptions of the cretaceous, eocene and miocene corals of the islands.– quarterly journal of the geological society of london, 21, 1–14. felix, j.p. (1903): studien über die korallenführenden schichten der oberen kreideformation in den alpen und in den mediterrangebieten [studies on the coral–bearing beds from the upper cretaceous formation of the alps and the mediterranean regions – in german].– palaeontographica, 49, 163–359. fromentel, e. de (1873): zoophytes, terrains crétacés [zoophytes, cretaceous terrains – in french].– in: orbigny, a. de (ed.): paléontologie francaise. masson, paris, 9, 385–432. fuente-navarro, m.j. de la (1964): estudio geológico del area cárdenas–rio verde, s.l.p., y arroyo seco, qro., méxico [geological study of the area cárdenasrio verde, s.l.p., and arroyo seco, qro, mexico – in spanish].– boletín de la asociación mexicana de geólogos petroleros, 16, 237–249. gili, e. & skelton, p.w. (2000): factors regulating the development of elevator rudist congregations.– in: insalaco, e., skelton, p.w. & palmer, t.j. (eds.): carbonate platform systems: components and interactions. geological society of london special publications, 178, 109–116. gili, e., masse, j.-p. & skelton, p.w. (1995): rudists as gregarious sediment-dwellers, not reef-builders, on cretaceous carbonate platforms.– palaeogeography, palaeoclimatology, palaeoecology, 118, 245–267. goldfuss, a. (1826): petrefacta germaniae (1) [fossils (petrefacts) of germany – in german].– arnz, düsseldorf, 1–114. goldhammer, r.k. & johnson, c.a. (2001): middle jurassic–upper cretaceous paleogeographic evolution and sequence-stratigraphic framework of the northwest gulf of mexico rim.– in: bartolini, c., buffler, r.t. & cantu-chapa, a. (eds.): the western gulf of mexico basin. aapg special memoir, 75, 45–82. götz, s. (2001): rudisten-assoziationen der keltiberischen oberkreide se-spaniens: paläontologie, palökologie und sediment–organismus–wechselwirkungen [rudist associations of the celtiberian upper cretaceous of se spain: paleontology, palecology and sediment-organism interactions – in german].– abhandlungen bayerische akademie der wissenschaften, naturwissenschaftliche klasse, 171, 112 p. götz, s. (2003): biotic interaction and synecology in a late cretaceous coral–rudist biostrome of southeastern spain.– palaeogeography, palaeoclimatology, palaeoecology, 193, 1–14. höfling, r. (1997): eine erweiterte riff-typologie und ihre anwendung auf kretazische biokonstruktionen [an expanded riff-typology and its application on cretaceous bioconstructions – in german].– abhandlungen bayerische akademie der wissenschaften, naturwissenschaftliche klasse, 169, 127 p. hurtado-gonzalez, b. (1984): implicaciones paleoecologicás de los moluscos cretácicos (bivalvia y gastropoda) de la región de ciudad del maíz, san luis potosí, méxico [paleoecological implications of cretaceous molluscans (bivalvia and gastropoda) from the region ciudad del maíz, san luis potosí, méxico – in spanish].– memoria del iii congreso latinoamericano de paleontología, 415–421. johnson, c.c. & kauffman, e.g. (1996): maastrichtian extinction patterns of caribbean province rudistids.– in: macleod, n. & keller, g. (eds.): cretaceous– tertiary mass extinctions: biotic and environmental changes. norton, w.w. & company, new york, 231–273. kauffman, e.g. (1973): cretaceous bivalvia.– in: hallam, a. (ed.): atlas of paleobiogeography. elsevier, amsterdam, 353–383. kauffman, e.g. & sohl, n.f. (1973): structure and evolution of antillean cretaceous rudist frameworks.– verhandlungen der naturforschenden gesellschaft basel, 84, 400–467. laviano, a. (1984): preliminary observation on the upper cretaceous coral–rudist facies of ostuni (south-eastern murge, apulia).– rivista italiana di paleontologia e stratigrafia, 90, 177–204. 196 geologia croatica 56/2 197schafhauser, götz, baron-szabo & stinnesbeck: depositional environment of... lopez-ramos, e. (1985): geologia de mexico, tomo ii [geology of mexico, part ii – in spanish].– inegi, ciudad de mexico, 454 p. masse, j.p. & philip, j. (1981): cretaceous coral–rudist buildups of france.– in: toomey, d.f. (ed.): european fossil reef models. society of economic paleontologists and mineralogists sepm (society of sedimentary geology), special publications, 30, 399–426. mitchell, s.f. (2002): palaeoecology of corals and rudists in mixed volcaniclastic–carbonate small-scale rhythms (upper cretaceous, jamaica).– palaeogeography, palaeoclimatology, palaeoecology, 168, 1–23. moran-zenteno, d. (1994): the geology of the mexican republic.– aapg studies in geology, 39, 160 p. moran-zenteno, d.j., martiny, b., tolson, g., solis-pichardo, g., alba-aldave, l., hernandez-bernal, s.m., romo-macias, c., martinez-serrano, r.g., schaaf, p. & romo-silva, g. (2000): geocronología y características geoquímicas de las rocas magmáticas terciarias de la sierra madre del sur [geochronology and geochemical characteristics of the tertiary magmatic rocks of the sierra madre del sur – in spanish].– boletín de la sociedad geológica mexicana, 53, 27–58. moro, a. (1997): stratigraphy and paleoenvironments of rudist biostromes in the upper cretaceous (turonian– upper santonian) limestones of southern istria, croatia.– palaeogeography, palaeoclimatology, palaeoecology, 131, 113–131. muellerried, f.k.g. (1930): un hippurites de la región de cárdenas, s.l.p. [one hippuritid from the cardenas region – in spanish].– anales del instituto de biología, 1, 165–168. myers, r.l. (1968): biostratigaphy of the cardenas formation (upper cretaceous) san luis potosí, mexico.– paleontología mexicana, 24, 89 p. oppenheim, p. (1930): die anthozoen der gosauschichten in den ostalpen [the anthozoans of the gosau beds from the eastern alps – in german].– privately published, berlin–lichterfelde, 604 p. orbigny, a. de (1850): prodrôme de paléontologie stratigraphique universelle [harbinger of universal stratigraphic paleontology – in french].– masson, paris, 2, 428 p. pettijohn, f.j., potter, p.e. & siever, r. (1984): sand and sandstone.– springer verlag, new york, berlin, heidelberg, london, paris, tokyo, 552 p. pindell, j.l., cande, s.c., pitman, w.c. iii, rowley, d.b., dewey, j.f., labrecque, j. & haxby, w. (1988): a plate-kinematic framework for models of the caribbean evolution.– tectonophysics, 155, 121–138. reuss, a.e. (1854): beiträge zur charakteristik der kreideschichten in den ostalpen, besonders im gosauthale und am wolfgangsee [contributions to characterize the cretaceous beds in the eastern alps, especially in the valley of gosau and at the lake wolfgang – in german].– denkschriften der kaiserlichen akademie der wissenschaften, mathematisch–naturwissenschaftliche classe, 7, 73–133. riding, r. (2002): structure and composition of organic reefs and carbonate mud mounds: concepts and categories.– earth-science reviews, 58, 163–231. ross, d.j. & skelton, p.w. (1993): rudist formations of the cretaceous: a palaeoecological, sedimentological and stratigraphical review.– sedimentology review, 1, 73–91. sanders, d. & baron-szabo, r.c. (1997): coral– rudist bioconstructions in the upper cretaceous haidach section (gosau group; northern calcareous alps, austria).– facies, 36, 69–90. sanders, d. & pons, j.p. (1999): rudist formations in mixed siliciclastic–carbonate depositional environments, upper cretaceous, austria: stratigraphy, sedimentology, and models of development.– palaeogeography, palaeoclimatology, palaeoecology, 148, 249–284. schafhauser, a., stinnesbeck, w., götz, s. & lopez-oliva, j.g. (2002): maastrichtian rudists of the cardenas formation (central mexico) connect northern gulf of mexico and yucatan fauna.– in: vlahović, i. & korbar, t. (eds.): 6th international congress on rudists, abstracts and excursion guidebook. institute of geology, zagreb, 67. scott, r.w. (1995): cretaceous rudists of guatemala.– revista mexicana de ciencias geológicas, 12/2, 294–306. scott, r.w., fernandez-mendiola, p.a., gili, e. & simo, a. (1990): persistence of coral–rudist reefs into the late cretaceous.– palaios, 5, 98–110. skelton, p.w. & gili, e. (1991): palaeoecological classification of rudist morphotypes.– in: sladić-trifunović, m. (ed.): 1st international conference on rudists. serbian geological society, spec. publ., 2, 265-287 [issued only as reprint from unpublished volume]. sohl, n.f., martinez, e.r., ureña-salmeron, p. & jaramillo-soto, f. (1991): upper cretaceous.– in: salvador, a. (ed.): the geology of north america: the gulf of mexico basin. geological society of america boulder, j, 205–244. steuber, t. (2002): depository item 2002022, list of occurrences of rudist bivalves (hippuritoidea) in the americas. plate tectonic control on the evolution of cretaceous platform-carbonate production.– geology, 30, 259, 71 p. steuber, t., mitchell, s.f., buhl, d., gunter, g. & kasper, h.u. (2002): catastrophic extinction of caribbean rudist bivalves at the cretaceous–tertiary boundary.– geology, 30, 999–1002. suter, m. (1987): structural traverse across the sierra madre oriental in east–central mexico.– geological society of america bulletin, 98, 249–264. torre, h.c. de la (1964): estudio geológico del area cerritos–cardenas [geological study of the area cerritos– cardenas – in spanish].– boletín de la asociación mexicana de geólogos petroleros, 16, 221–235. tucker, m. (1990a): coastal and offshore environments.– in: tucker, m. & wright, v.p. (eds.): carbonate sedimentology. blackwell scientific publications, london, 101–126. tucker, m. (1990b): modern carbonate environments.– in: tucker, m. & wright, v.p. (eds.): carbonate sedi198 geologia croatica 56/2 mentology. blackwell scientific publications, london, 101–126. tucker, m. (1990c): shelf margin sand bodies.– in: tucker, m. & wright, v.p. (eds.): carbonate sedimentology. blackwell scientific publications, london, 101–126. vaughan, t.w. (1899): some cretaceous and eocene corals from jamaica.– bulletin of the museum of comparative zoology, 34, 227–250. vaughan, t.w. (1923): fauna of the sooke formation, vancouver island, description of a new coral.– publications of geology, university of california, 14, 175–176. vega, f.j., feldmann, r.m. & sour-touvar, f. (1995): fossil crabs (crustacea: decapoda) from the late cretaceous cárdenas formation, east–central mexico.– journal of paleontology, 69, 340–350. wells, j.w. (1934): some fossil corals from the west indies.– proceedings of the u.s. natural museum, washington, 83, 71–110. ye, h. (1997): the arcuate sierra madre oriental orogenic belt, ne mexico: tectonic infilling of a recess along the southwestern north american continental margin.– in: soegaard, k., giles, k., vega, f.j. & lawton, t. (eds.): structure, stratigraphy and paleontology of late cretaceous–early tertiary parras–la popa foreland basin near monterrey, northeast mexico. aapg field trip, 82–115. manuscript received march 24, 2003. revised manuscript accepted november 04, 2003. 06-sondi.indd 61 � ab stra ct a novel approach, designated as the particle-mediated, nano-scale, aggregation route, to the formation and growth of spherical and colloid-sized anhydrous carbonate mineral particles and hierarchically organized biomineral carbonate structures is discussed. this model is inconsistent with the conventional crystallization mechanism, which is primarily based on diffusion growth. it is determined by the initial formation of nanosized, crystalline particles, (singlets), and their subsequent aggregation into submicrometre and micron-sized carbonate particle assemblies. this concept is much more common in nature than has previously been assumed. the number of new examples of its signifi cance in the formation of inorganic and biogenic carbonate mineral solids has signifi cantly increased in recent years. a few illustrations are presented to show the appearance of nanostructured and hierarchically organized carbonate particles formed through the nano-scale aggregation route in natural systems, together with those obtained from laboratory model experiments. keywords: aggregation, carbonates, mechanism of formation a novel concept in the growth and design of anhydrous carbonate minerals: nano-scale aggregation mechanisms � ivan sondi1*, srečo d. škapin2, irena jurina1 and damir slovenec3 1center for marine and environmental research, ruđer bošković institute, zagreb, croatia; (*corresponding author: sondi@irb.hr) 2advanced materials department, jožef stefan institute, ljubljana, slovenia; (sreco.skapin@ijs.si) 3croatian geological survey, sachsova 2, zagreb, croatia; (damir.slovenec@hgi-cgs.hr) doi: 104154/gc.2011.06 geologia croatica 64/1 61–65 6 figs. zagreb 2011 geologia croaticageologia croatica 1. introduction anhydrous carbonate minerals are frequently found in nature, commonly occurring as the main mineral constituents in rocks and sediments, and as the most common constituents of the bio-inorganic structures of the skeletons and tissues of many mineralizing organisms (tucker & wright, 1990; flügel, 2004; sondi & juračić, 2010; sondi et al., 2011). physico-chemical processes leading to the formation of anhydrous calcium carbonate polymorphs, i.e., vaterite, aragonite, and calcite, of different structures, sizes, morphologies, and surface properties, have been intensively investigated because of their importance in geo and biosciences (addadi & weiner, 1992; richter et al., 1995; wang et al., 1999; sondi & juračić, 2010). most of the previously reported studies deal with the precipitation of calcium carbonate minerals in aqueous media through classical diffusion-type crystal growth (westin & rasmuson, 2005). during the past decade, the formation of carbonate mineral particles exhibiting unusual structural, morphological and physical properties has been investigated in terms of their mineralogy, biology and chemistry (meldrum, 2003; geologia croatica 64/1geologia croatica 62 sondi & salopek-sondi, 2005; meldrum & cölfen, 2008; vielzeuf et al., 2008). lately, a new concept, the particle-mediated, non-classical crystallization process, in the formation of bio-inorganic, mesoscopically structured mesocrystals, was promoted (cölfen & antonietti, 2005; niedeberger & cölfen, 2006; wang et al., 2006). these structures are composed of nanoparticle building blocks, and are characterized by a well-faceted appearance and anisotropic properties. this concept is much more common in biomineralization processes than has previously been assumed, and the number of new examples of the signifi cance of mesocrystals in biomineral formation has signifi cantly increased in recent years. so far, only scant attention has been devoted to the formation of uniform and nearly spherical anhydrous carbonate particles, devoid of crystal habits and anisotropic properties, but still maintaining a crystal structure (sondi & ma tijević, 2003; sondi & salopek-sondi, 2005; sondi et al., 2008). the aim of this note is to discuss recent advances in the formation of well-defi ned and uniform nanostructured, colloidal carbonate particles, through the non-classical, inorganically and biologically induced nano-scale ag gregation route and to identify some of the problems that still need to be addressed. 2. case report and discussion the mechanisms of formation of unusual mineral structures and complex shapes have been a topic of discussion for decades. morphological diversity and complexity of naturally occurring minerals in natural systems arises from the diferent physico-chemical mechanisms involved in their growth. the well-established, classical diffusion crystal-growth mechanism proposed by lamer & dinegar (1950) suggests that colloidal mineral particles are formed when nuclei, coming from a short-lived burst, grow from the attachment of constituent solutes. during the past decade, further, unique, observations were presented including the formation of unusually uniform, spheroidal calcium carbonate particles of distinct crystallinity, despite the fact that they are aggregates of nanosized subunits (sondi & matijević, 2001; sondi & salopek-sondi, 2005). the signifi cance of the aggregation process in the formation of mineral particles from preformed nanocrystallites had already been observed in the late 1960s (petres et al., 1969). however, this disocvery has long remained neglected. recently, it has been experimentally and theoretically established that many inorganic colloids, prepared by precipitation from homogeneous solutions, are composed of nanosized subunits (bailey et al., 1993; sondi & matijević, 2003; he et al., 2004; liu & zheng, 2004; škapin & sondi, 2005). therefore, this mechanism was shown to be relatively common in the formation of colloidal particles with crystalline characteristics (privman et al., 1999; navrotsky, 2004; nie deberger & cölfen, 2006). several important studies reported and discussed the formation of unusual structures based on a non-classical mechanism involving aggregation processes (sondi & sa lopek-sondi, 2005; privman et al., 1999; bailey et al., 1993), oriented aggregation assembly (penn & banfield, 1999; alivisatos, 2000; banfield et al., 2000), the development of an oriented architecture of bridged nanocrystals embedded in an organic matrix (oaki et al., 2006) and the recently developed mesocrystal concept (cölfen & antonietti, 2005; song & cölfen, 2010). comprehensive coverage of all these would be impractical here. instead, a few basic examples are given concerning the aggregation mechanism involved in formation of nanostructured and colloidal mineral particles with remarkable morphological properties. firstly, consider the example of simple aggregation of carbonate colloid particles. figure 1 displays a fi eld-emission scanning electron microphotograph (fesem) of unusual spherical and colloid-sized carbonate particles taken from fi gu re 1: fesem of spherical calcite particles composed of smaller nanosized units (the samples originate from the sediment of the freshwater lake of jezero kuti located on the neretva river delta plain). unpublished illustrations. fi gu re 2: fesem photomicrographs of spheroidal colloid-sized vaterite particles obtained by the enzyme-catalyzed decomposition of urea by urease in aqueous calcium salt solutions at room temperature. (figure adapted from sondi & salopek-sondi, 2005). sondi et al.: a novel concept in the growth and design of anhydrous carbonate minerals: nano-scale aggregation mechanisms geologia croatica 63 modern surface sediment of kuti lake, part of the deltaic system of the neretva river, croatia. at much higher magnifi cation it is clear that these solids are composed of much smaller aggregated nanosized subunits (inset in fig. 1). this implies that these solids did not follow the growth pattern through the classical crystallization pathways and diffusion growth, but rather were formed by the nonconventional aggregation of initially formed nanocrystallites. analagous to this observation, fig. 2 displays an fesem photomicrograph of uniform and spherical colloid-sized vaterite particles obtained in the laboratory by the enzyme-catalyzed decomposition of urea using the urease enzyme in aqueous calcium salt solutions at room temperature (sondi & salopeksondi, 2005). almost identical structures, (spherical colloid-sized vaterite particles, composed of much smaller nanosized singlets), were observed. notably, the xrd peaks of the latter precipitate were signifi cantly widened, additionally indicating that these spherical particles are composed of nanosize crystallites (fig. 3). applying the debye-scheerer equation, their size was estimated to be ~30 nm. in addition, sondi & matijević (2003) also demonstrated that uniform and spheroidal anhydrous carbonate particles from the aragonite group, witherite (baco3) and strontianite (srco3), generated through a biomimetic precipitation process, also consisted of nanosized subunits. following these fi ndings, aggregation processes at the nano-scale should be considered as an important mechanism in the formation of crystalline and colloidal carbonate mineral particles that are generated fi gu re 3: xrd pattern of vaterite (v) precipitate obtained by aging a solution containing 0.5 mol dm–3 urea, 0.2 mol dm–3 cacl2, and 0.5 mg cm–3 b. pasteurii urease at 25 °c for 2 min. (figure adapted from sondi & salopek-sondi, 2005). fi gu re 4: fesem photomicrographs of diff erent types of morphology on the native surface of a septal unit within the calyx: submicrometre-sized, nearly spherical crystallites (a), transitional forms of elongated cone structures built up of submicrometre-sized particles (b,c), and elongated aragonite fi bres (d). (figure adapted from sondi et al., 2011). geologia croatica 64/1geologia croatica 64 in natural systems through complex biogeochemical processes, and through the laboratory model experiments under various experimental conditions. recently, several important studies have reported and dis cussed the fi ne-scale growth of unusual and hierarchically or ganized bio-inorganic aragonite structures involving a more complex, oriented nano-scale aggregation route (sethmann et al., 2007; vielzeuf et al., 2008; sondi et al. 2011). it was demonstrated that the internal crystal growth of aragonite fi bres is governed by the aligned aggregation of preformed nanocrystallites and the subsequent coalescence processes that occur simultaneously. as an example, fig. 4 demonstrates the essential principle of the ma trix-mediated sequential growth of hierarchically organized fi brous aragonite structures in a skeleton of mediterranean zooxanthellate scleractinian coral cladocora caespitosa involving the nanoscale aggregation route (sondi et al., 2011). it is based on an initial organic matrix-mediated formation of nanosized spherulites in the centres of calcifi cation (fig. 4a) and followed by the growth of aggregated and oriented cone-cluster assemblies, that are gradually built up of smaller nanosized units (figs. 4b, c). what ensues is their subsequent morphological conversion through the coalescence of primarily formed nanoparticles and the formation of aligned fi brous units (fig. 4d). figure 5 is an fesem photomicrograph of unusual sphe roidal aragonite particles of distinct crystallinity, which were aggregates of nanosized subunits obtained in the laboratory in an aqueous calcium salt solution containing urea and ethylene glycol at an elevated temperature of 160°c (škapin & sondi, 2010). organization of the nanosized subunits of these aragonite particles closely resembles that of the fi brous aragonite in the skeleton of c. caespitosa shown in fig. 4d. these fi ndings confi rm the hypothesis that the oriented aggregation is a common mechanism in the formation of naturally occurring and laboratory-obtained, hierarchically organized aragonite structures. the appearance of nanostructured and hierarchically shaped bio-mineral structures in nature is the rule rather than a chance event. various organisms base the functionality of their structural components on the formation of nanostructured materials, functionally adapted to the living environment through the aggregation mechanisms. figure 6 shows an example of the heterotrophic protozoa that build up their lorica from highly organized and nanostructured calcium carbonate solids (sondi & škapin, 2010). as a fi nal remark, the entire understanding of the role of the nano-scale aggregation processes in the formation of nanostructured colloidal carbonate minerals is still in its infancy. further, more detailed and delicate investigations, focused on the formation of nanosized precursor phases and their mutual specifi c physico-chemical interactions at the initial stage of their formation, might clarify the mechanism of the entire precipitation process. 3. conclusions this note underscores the importance of nano-scale aggregation processes in the formation of biogenic and inorganic colloid-sized carbonate mineral particles. understanding these mechanisms sheds light on the non-conventional formation of carbonate mineral phases in modern sediments, a situation commonly encountered in natural systems. it needs to be pointed out that aggregation mechanisms are too complex to entirely determine the role of single processes of chemical and physical events involved in the formation of aggregated mineral solids in natural systems. it is clear that more focused and detailed investigations of substructured carbonate minerals from sedimentary systems, together with those obtained by model laboratory experiments could possibly contribute to the clarifi cation of the mechanism of the aggregation processes encountered in bioinorganic and inorganic mineral structures in nature. fi gu re 5: fesem photomicrographs of aragonite obtained by ageing ethylene glycol solution containing 0.75 mol dm−3 urea, 0.25 mol dm−3 cacl2 at 160°c for 10 min. (figure adapted from škapin & sondi, 2010). fi gu re 6: fesem photomicrographs of heterotrophic protozoa showing the nanostructured shape of their lorica (the samples originate from the sediment of the marine lake of malo jezero on the island of mljet, adriatic sea). (figure adapted from sondi & škapin, 2010). sondi et al.: a novel concept in the growth and design of anhydrous carbonate minerals: nano-scale aggregation mechanisms geologia croatica 65 acknowledgement this work was supported by the ministry of science, education and sports of the republic of croatia (grants 0980982934-2742, 119-0000000-1158), and by the ministry of higher education, science and technology of the republic of slovenia (grant p2-0091-0106). references alivisatos, a.p. (2000): biomineralization: naturally aligned nanocrystals.– science, 289, 736−737. addadi, l. & weiner, s. (1992): control and design principles in bio logical mineralization.– angew. chem. int. ed. engl., 31, 153−169. bailey, k., brinker, c.j. & mecartney, m.l. (1993): growth mechanisms of iron oxide particles of differing morphologies from the forced hydrolysis of ferric chloride solutions.– j. colloid interface sci., 157, 1−13. banfield, j.f., welch, s.a., zhang, h., ebert, t.t. & penn, r.l. (2000): aggregation-based crystal growth and microstructure development in natural iron oxyhydroxide biomineralization products.– science, 289, 751−754. cölfen, h. & antonietti, m. (2005): mesocrystals: inorganic superstructures made by highly parallel crystallization and controlled alignment.– angew. chem. int. edit., 44, 5576−5591. flügel, e. (2004): microfacies of carbonate rocks.– springer, berlin, heidelberg, new york, 976 p. he, t., chen, d. & jiao, x. (2004): controlled synthesis of co3o4 nanoparticles through oriented aggregation.– chem. mater., 16, 737−743. lamer, v.k. & dinegar, r. (1950): theory, production and mechanism of formation of monodispersed hydrosols.– am. chem. soc., 72, 4847−4854. liu, b. & zeng, h.c. (2004): mesoscale organization of cuo nanoribbons: formation of “dandelions”.– j. am. chem. soc., 126, 8124–8125. meldrum, f.c. (2003): biomimetic control of calcifi cation.– int. mater. rev., 48, 187–224. meldrum, f.c. & cölfen, h. (2008): controlling mineral morphologies and structures in biological and synthetic systems.– chem. rev., 108, 4332–4432. navrotsky, a. (2004): energetic clues to pathways to biomineralization: precursors, clusters and nanoparticles.– p. natl. acad. sci. usa, 101, 12096–12101. niederberger, m. & cölfen, h. (2006): oriented attachment and mesocrystals: non-classical crystallization mechanisms based on nanoparticle assembly.– phys. chem. chem. phys, 8, 3271–3287. oaki, y., kotachi, a., miura, t. & imai, h. (2006): bridged nanocrystals in biominerals and their biomimetics: classical yet modern crystal growth on the nanoscale.– adv. funct. mater., 16, 1633–1639. penn, r.l. & banfield, j.f. (1999): morphology development and crystal growth in nanocrystalline aggregates under hydrothermal conditions: insights from titania.– geochim. cosmochim. acta, 63, 1549–1557. petres, j.j., deželić, gj. & težak, b. (1969): monodisperse sols of barium sulfate. iii. electron-microscopic study of internal structure of particles.– croat. chem. acta, 41, 183–186. privman, v., goia, d.v., park, j. & matijević, e. (1999): mechanism of formation of monodispersed colloids by aggregation of nanosize precursors.– j. colloid interface sci., 213, 36–45. richter, a., petzold, d., hofma n, h. & ullrich, b. (1995): herstellung, eigenschaften und verwendung von calciumcarbonatpulvern. teil 1: herstellung von calciumcarbonat durch fallung aus loesungen.– chem. tech., 47, 306–313. sethmann, i., helbig, u. & worheide, g. (2007): octocoral sclerite ultrastructures and experimental approach to underlying biomineralisation principles.– cryst. eng. comm., 9, 1262–1268. sondi, i. & matijević, e. (2001): homogenous precipitation of calcium carbonate by enzyme catalyzed reactions.– j. colloid interface sci., 238, 208–214. sondi, i. & matijević, e. (2003): homogeneous precipitation by enzyme-catalyzed reactions. 2. strontium and barium carbonates.– chem. mater., 15, 1322–1326. sondi, i. & salopek-sondi, b. (2005): infl uence of the primary structure of enzymes on the formation of caco3 polymorphs: a comparison of plant (canavalia ensiformis) and bacterial (bacillus pasteurii) ureases.– langmuir, 21, 8876–8882. sondi, i., škapin, s.d. & salopek-sondi, b. (2008): biomimetic precipitation of nanostructured colloidal calcite particles by enzyme-catalyzed reaction in the presence of magnesium ions.– cryst. growth des., 8, 435–441. sondi, i. & juračić, m. (2010): whiting events and the formation of aragonite in mediterranean karstic marine lakes: new evidence on its biologically induced inorganic origin.– sedimentology, 57, 85–95. sondi, i. & škapin, s.d. (2010): a biomimetic nano-scale aggregation route for the formation of submicron-size colloidal calcite particles.– in: mukherjee, a. (ed.): biomimetics, learning from nature. in-tech, vienna, 241–255. sondi, i., salopek-sondi, b., škapin, s.d., šegota, s., jurina, i. & vukelić, b. (2011): colloid-chemical processes in the growth and design of the bio-inorganic aragonite structure in the scleractinian coral cladocora caespitosa.– j. colloid interface sci., 354, 181–189. song, r.q. & cölfen, h. (2010): mesocrystals – ordered nanoparticle superstructures.– adv. mater., 22, 1301–1330. škapin, s.d. & sondi, i. (2005): homogeneous precipitation of mixed anhydrous ca-mg and ba-sr carbonates by enzyme-catalyzed reactions.– cryst. growth des., 5, 1933–1938. škapin, s.d. & sondi, i. (2010): synthesis and characterization of calcite and aragonite in polyol liquids: control over structure and morphology.– j. colloid interface sci., 347, 221–226. tucker, m.e. & wright, v.p. (1990): carbonate sedimentology.– blackwell scientifi c publications, oxford, 482 p. vielzeuf, d., garrabou, j., baronnet, a., grauby, o. & marschal, c. (2008): nano to macroscale biomineral architecture of red coral (corallium rubrum).– am. mineral., 93, 1799–1815. wang, l., sondi, i. & matijević, e. (1999): preparation of uniform needle-like aragonite particles by homogeneous precipitation.– j. colloid interface sci., 218, 545–553. wang, t.p., antonietti, m. & cölfen, h. (2006): calcite meso crystals: “morphing” crystals by a polyelectrolyte.– chem. eur. j., 12, 5722–5730. westin, k. & rasmuson, a.c. (2005): crystal growth of aragonite and calcite in presence of citric acid, dtpa, edta and pyromellitic acid.– j. colloid interface sci., 282, 359–369. manuscript received december 09, 2010 revised manuscript accepted january 12, 2011 available online february 22, 2011 lower and middle liassic calcareous algae (dasycladales) from mt. velebit (croatia) and mt. trnovski gozd (slovenia) with particular reference to the genus palaeodasycladus (pia, 1920) 1927 and its species branko soka» geologia croatica 54/2 133 257 8 figs. 17 tabs. 42 pls. zagreb 2001 key words: calcareous algae (dasycladales), lowermiddle liassic, croatia, slovenia. institute of geology, sachsova 2, hr-10000 zagreb, croatia; e-mail: igi-zagreb@zg.hinet.hr abstract based on the characteristics of individual species, the generic characteristics of p a l a e o d a s y c l a d u s have been determined and enlarged. p . m e d i t e r r a n e u s (p i a, 1920) 1927 comprises a broad array of varieties that have been taxonomically distinguished on the basis of the variable shape of primary and secondary branches and the way in which the secondaries emerge. the following varieties are represented: p . m e d i t e r r a n e u s (pia, 1920) 1927 var. m e d i t e r r a n e u s , p. mediterra neus var. heraki (soka» & nikler, 1966) n. comb., p. mediterra neus var. illyricus (soka» & nikler, 1966) n. comb., p. mediter r a n e u s var. g r a c i l i s (cros & lemoine, 1967 ex granier & deloffre, 1993) n. stat., p. mediterraneus var. e l o n g a t u l u s praturlon, 1966, and p. mediterraneus var. c a l c i t i c u s n. var., and are characterised by specific skeletal form and easily recognisable calcification pattern. also, the generic assignment of p. barrabei lebouché & lemoine, 1963 ex granier & deloffre, 1993 has been confirmed, in spite of its recent transferral to e o d a s y c l a d u s by barattolo et al. (1994). the following new species have been described: palaeodasycladus alanensis n. sp., characterised by broadened, bowl-shaped or bushy swollen primary branches; p. multiporus n. sp., characterised by numerous higher-order branches on each primary branch; p. benceki n. sp., with very large primary branches with extremely variable distal ends; and p. aster i s c u s n. sp., with loosely spaced whorls and variously directed secondary branches, often growing in opposite directions from the same primary branch. lower liassic species, previously ascribed to f a n e sella, f. dolomitica and f. anae , have also been assigned to p a l a e o d a s y c l a d u s with enlarged generic characteristics and are named, consequently, palaeodasycladus dolomiticus (cros & lemoine, 1966) n. comb. and p. anae (s o k a », 1988) n. comb., respectively. fanesella sokaci barattolo & bigozzi, 1996 is considered to be a younger synonym of p. dolomiticus. phylogenetic relationships between various taxa have also been considered and a phyletic lineage p. barrabei p. alanensis p. benceki has been shown to exist. as regards the relationship between p a l a e o d a s y c l a d u s a n d e o d a s y c l a d u s, the latter has been shown to have evolved directly from p. barrabei by enlarged and more pronounced bubble-shaped swelling of one of the secondary branches, which thus becomes a “sporangia-bearing” organ. also, a new species tentatively assigned to the genus selliporella, selliporella? problematica n. sp., has been described. from its morphological characteristics it represents an intermediate form, and a phylogenetic link between liassic p a l a e o d a s y c l a d u s and middle jurassic s e l l i p o r e l l a . finally, a new species, h u m i e l l a j a p o d i c a n. sp. has been described, thereby enlarging the stratigraphic range of the genus humiella into the lower liassic. 1. introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. taxonomic descriptions ..........................................................3 genus palaeodasycladus (pia, 1920) 1927 ....................................3 palaeodasycladus mediterraneus (pia, 1920) 1927 var. m e d i t e r r a n e u s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 palaeodasycladus mediterraneus var. heraki (soka» & nikler, 1966) n. comb. .......................................................9 palaeodasycladus mediterraneus var. illyricus (soka» & nikler, 1966) n. comb. .....................................................12 palaeodasycladus mediterraneus var. gracilis (cros & lemoine, 1967 ex granier & deloffre, 1993) n. stat. .................................................................................13 palaeodasycladus mediterraneus var. elongatulus praturlon, 1966 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 4 palaeodasycladus mediterraneus var. calciticus n. var. ........17 remarks on the taxonomic classification of newly established varieties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 8 distinguishing characteristics of the established varieties ......19 palaeodasycladus barrabei lebouché & lemoine, 1963 ex granier & deloffre, 1993 ............................21 taxonomic validation of palaeodasycladus barrabei lebouché & lemoine and its relationship with eodasycladus ogilviae cros & lemoine .......................24 palaeodasycladus alanensis n. sp. ........................................25 palaeodasycladus dolomiticus (cros & lemoine, 1966) n. comb. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 6 main characteristics of the genus fanesella...................................26 comparison of the main characteristics of the genera palaeodasycladus and fanesella and the proposal for their unification....26 palaeodasycladus anae (soka», 1988) n. comb. ................28 palaeodasycladus multiporus n. sp. .......................................29 palaeodasycladus benceki n. sp. ...........................................32 palaeodasycladus asteriscus n. sp. .......................................34 genus eodasycladus cros & lemoine, 1966 ex granier & deloffre, 1993 ...................................................................35 eodasycladus ogilviae cros & lemoine, 1966 ..................36 genus selliporella sartoni & crescenti, 1962 emend. barattolo et al., 1988 ...........................................................37 selliporella? problematica n. sp. .............................................37 genus humiella soka» & veli∆, 1981 emend. masse et al., 1984 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 9 humiella japodica n. sp. .........................................................39 a c k n o w l e d g e m e n t s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 0 3. references . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 0 plates i-xlii ......................................................................................42 contents 134 geologia croatica 54/2 1. introduction during many years of field work in the dinaridic karst, numerous liassic (lower jurassic) outcrops were studied in an area ranging from trnovski gozd, slovenia, to the north-west, to konavoska brda, south-east of dubrovnik, croatia, in the south-east. among the abundant fossil material, calcareous algae (dasycladales) were well represented, with the genus p a l a e o d a s y c l a dus and its type-species, p. mediterraneus (pia), being the most common. for almost forty-five years the genus was represented solely by its type species, which was frequently quoted and often illustrated from lower and middle liassic deposits of the peri-mediterranean region. after a fairly long time, another species, p a l a e o dasycladus barrabei , was added by lebouché & lemoine (1963) and a new variety, p. mediterraneus var. e l o n g a t u l u s was introduced by praturlon (1966). at the same time, cros & lemoine (1967) described a new species, p. gracilis , but added, in a subsequently inserted footnote, that it probably represented a younger synonym of p. mediterraneus v a r . e l o n g a t u l u s. putting aside, for the moment, the discussions about mutual relationships between individual species, their validity, and their distinctive features (see below, in the description of individual taxa), it remains unclear why no one attempted to perform a detailed revision of the original description of the genus (pia, 1920) and its later emendation (pia, 1927), in spite of numerous finds. some workers (bouroullec & deloffre, 1970; deloffre, 1972; lebouché & lemoine, 1963; cros & lemoine, 1967) commented on the typical properties of the genus and its type-species, but no new observations were added to the original descriptions. some features mentioned by pia, such as the club-like shape of the thallus in p. me d i t e r r a n e u s (which was never illustrated by a photograph), or the intusannulation, seemed to be passed over from one description to the next without critical checking. thus in the monograph of bassoullet et al. (1978, p. 187), intusannulation was mentioned as a generic characteristic, probably influenced by the fact that it is mentioned in the descriptions of all species. only more recently, have the genus and its species received more attention. thus deloffre & laadila (1990) proposed the generic description to be completed with some new characteristics, which, however, were observed in specimens (sections) which most likely do not belong to the type-species, in spite of being so assigned by the authors. they also consider p. barrabei lebouché & lemoine to be identical with p. me d i t e r r a n e u s and hence to represent its younger synonym, and for p. elongatulus they agree with the original authors in its being a variety of the type-species. later, barattolo et al. (1994) critically reviewed the paper by deloffre & laadila (1990) and expressed their disagreement with some additional features ascribed by deloffre & laadila (1990) to the type-species. they also, on the basis of abundant material from the type locality, stated some new observations for p. mediterraneus , but warned that they represented only the first step towards the full understanding of the morphology of that species. they also, based on their own observations and some morphological features, revised p. barrabei lebouché & lemoine and proposed its transferral into the genus e o d a s y cladus. they reject the opinion of deloffre & laadila (1990) that p. barrabei possibly represents a younger synonym of p. mediterraneus . for p a l a e o dasycladus gracilis cros & lemoine ex granier & deloffre, 1993, or, as labelled by barattolo et al. (1994), p. mediterraneus var. e l o n g a t u l u s p r aturlon, 1966, the taxonomic status remains unclear and rather controversial. according to barattolo et al. (1994), this form cannot be considered a variety or a subspecies of p. mediterraneus , but in order to definitely resolve whether it is a morphotype in the p . mediterraneus group or a distinct taxon, further detailed studies are necessary. later, barattolo & bigozzi (1996) again reconsidered numerous specimens (sections) of p. mediterraneus from gran sasso, but with a morphology different from the type material (as illustrated by barattolo et al., 1994). barattolo & bigozzi (1996) distinguish between two extreme morphologies, expressed in the shape of secondary and tertiary branches: the first one is smaller, with more slender secondaries and clearly phloiophorous tertiaries, whereas the second one has large and densely packed secondaries and tertiaries. they also mention that, for the time being, and for want of a quantitative study with comparison, they consider the various morphologies as one species. in the same paper, barattolo & bigozzi (1996) also discuss p a l a e o d a s y cladus gracilis (= p. mediterraneus var. e l o n g a t u l u s praturlon), adding some new observations concerning the clearly club-shaped thallus, degree of calcification, and shape of branches, which are partly different from those in the original description by cros & lemoine (1967). these features will be discussed in more detail below, in the description of individual taxa. because our understanding of the genus p a l a e o d a s y c l a d u s is primarily based on the type-species, with only subordinate observations made on later described species, every new observation, i.e. every hitherto undescribed feature, in the type-species is of particular interest for better understanding of the genus in general. no doubt, barattolo et al. (1994) and barattolo & bigozzi (1996), in their analysis of the typespecies and other species of the genus p a l a e o d a s y c l a dus, made important contributions to our greater understanding of that genus; however, some of their considerations are open for critical reconsideration, particularly regarding the interpretation of some features, valorisation of some species, and their proposed taxonomic position. the purpose of the present paper is to discuss some open problems and to present new arguments about some controversial opinions, based on abundant illustrated material. the work has been undertaken by examination of more than 1,000 thin sections, from mt. velebit (figs. 1 and 2), which contained a large number of variously oriented specimens. in spite of the fact that the material was often recrystallised, or, more rarely, micritized, the large number of available sections made it possible to: provide a new contribution to the understanding of the genus, its type-species and the later described species; to express various opinions regarding the validity of some species and some generally accepted characteristics; to describe several new species; to establish new and to propose the abandonment of some existing genera; and to indicate some possible phylogenetic relationships within the genus and establish the sequence of evolutionary changes between some genera of the same or similar stratigraphic position. 2. taxonomic descriptions order dasycladales family dasycladaceae genus palaeodasycladus (pia, 1920) 1927 selected synonymy: 1920 p a l a e o c l a d u s n. gen. pia, p. 118-122, fig. 22, pl. 6, figs. 1-5. 1927 p a l a e o d a s y c l a d u s nom. nov. pia (in hirmer), p. 79, fig. 62. 1963 p a l a e o d a s y c l a d u s pia, 1927 (= p a l a e o c l a d u s pia, 1920) lebouché & lemoine, p. 95. 1967 p a l a e o d a s y c l a d u s pia, 1927 (= p a l a e o c l a d u s pia, 1920) cros & lemoine, p. 250. 1970 p a l a e o d a s y c l a d u s pia, 1927 (= p a l a e o c l a d u s pia, 1920) bouroullec & deloffre, p. 88. 1978 p a l a e o d a s y c l a d u s pia, 1927 bassoullet et al., p. 187, pl. 22, figs. 8-9, pl. 23, figs. 1-2. 1990 p a l a e o d a s y c l a d u s (pia, 1920) pia 1927 deloffre & laadila, p. 318-319, non pl. 1-3. 1993 p a l a e o d a s y c l a d u s (pia, 1920) deloffre & laadila, 1990 (= p a l a e o c l a d u s pia, 1920) granier & deloffre, p. 36-37. 1994 p a l a e o d a s y c l a d u s (pia, 1920) pia 1927 barattolo; de castro & parente, p. 1-4, pl. 1, figs. 1-4. the original diagnosis by pia (1920) was comparatively scant but pia rightly emphasised that a fully adequate and reliable generic diagnosis must not be based on a single species. a concise, though somewhat more detailed, diagnosis was given by bassoullet et al. (1978, p. 187). based on the present material, the generic diagnosis can be summarised as follows: the thallus may be straight or slightly bent, cylindrical or slightly club-shaped, with an even or slightly undulated or annulated outer surface. central cavity is cylindrical or quite regularly undulated, with or without intusannulation developed to a variable degree. primary branches arranged in clear whorls; they bear secondary, tertiary, and, sometimes, fourth-order branches. primaries may be variously shaped, whereas the secondaries, tertiaries and fourth-order branches are acrophorous or phloiophorous. distal branches are more strongly phloiophorous. secondaries grow out of the primaries either as finger-like protrusions or are constricted at their base. sometimes the secondaries and tertiaries may be constricted, giving a seemingly articulated appearance. the position of ramifications with regard to the longitudinal axis of growth may vary from perpendicular to steeply directed upwards, almost parallel to the longitudinal axis. it is supposed that the lower part of the thallus may show a lesser degree of ramification, so that only primaries and secondaries may be developed. the genus is basically cladosporous, but in some forms endospory cannot be excluded; still other forms indicate the beginnings of choristosporous development. because some characteristics of the type-species or other species are at the same time basic characteristics of the genus, they will be discussed below, in the descriptions of individual taxa. palaeodasycladus mediterraneus (pia, 1920) 1927 var . mediterraneus pls. i-v; pl. vi, figs. 1-6; pl. vii, figs. 3, 5-9; pl. viii, figs. 2-8; pl. ix, figs. 1, 8; pls. x-xi; pl. xii, figs. 2-5, part. 6; pl. xiii, figs. 1-3, 6-7; pl. xiv, figs. 1-4, 7, 9, part. 8; pl. xv, figs 1, 3-9; fig. 3 selected synonymy: 1920 palaeocladus mediterraneus n. gen., n. sp. pia, p. 118, fig. 22; pl. vi, figs. 1-5. 1927 palaeodasycladus mediterraneus pia -pia; in hirmer, p. 79-80, fig. 62. 1966 palaeodasycladus mediterraneus pia radoi»i∆, pl. 1, figs. 1-2; pl. 19, figs. 1-2; pl. 89, fig. 1; pl. 91, figs. 1-2; pl. 110, fig. 1; pl. 143, figs. 1-2. 1968 palaeodasycladus mediterraneus pia nikler & soka», pl. 1, fig. 1; pl. 3, figs. 1-3. 1978 palaeodasycladus mediterraneus (pia) 1920 bassoullet et al., p. 192-197, pl. 22, figs. 89; pl. 23, figs 1-2. non 1990 palaeodasycladus mediterraneus ( p i a , 1920) deloffre & laadila, p. 309-320, pl. 1, ?figs. 1-3; pl. 2, non figs. 1-4; pl. 3, non figs. 1-3. 135sokaë: lower and middle liassic calcareous algae (dasycladales)... 136 geologia croatica 54/2 1994 palaeodasycladus mediterraneus (pia, 1920), pia 1927 barattolo, de castro & parente, p. 1-11, pl. 1, figs. 1-4. 1994 palaeodasycladus mediterraneus (pia, 1920), pia 1927 emend. deloffre & laadila 1990 dragastan et al., p. 59-60, pl. 1, figs. 1-2, ?7. 1996 palaeodasycladus mediterraneus (pia) barattolo & bigozzi, p. 205, pl. 44, figs. 12. 1997 palaeodasycladus mediterraneus (pia) de castro, pl. 15; pl. 16, figs. 1-4; pl. 24, figs. 12; pl. 25, figs. 1-3; pl. 26, figs. 1-3. the species was first described by pia (1920) under the name of palaeocladus mediterraneus , to be later renamed and more completely described as p a l a e o d a s y c l a dus mediterraneus pia (1927). the main species-specific characteristics were given in the description of the genus, which for a long time remained monospecific. in the original description, pia (1920), probably on the basis of observations made on a number of different sections, produced a reconstruction (pia, 1920, p. 121, fig. 22), which, as emphasised by barattolo et al. (1994), may be considered hypothetical if based only on the sections figured by pia (pia, 1920, pl. 6, figs. 1-5) but proved to be very successful indeed if compared with other sections (e.g., de castro, 1967, pl. 15, pl. 16, figs 1,3; present paper, pl. i, figs. 2, 5; pl. ii, fig. 3). this reconstruction suggests that pia had additional sections, perhaps even better than those figured in the original description. barattolo et al. (1994) have studied abundant material from the type-locality. they introduced a neotype and stated some complementary remarks and interpretations of some features, such as intusannulation and the appearance of spherical and elongated tubular structures in the branches, which they considered to be reproductive structures (barattolo et al., 1994, pl. 1, figs. 1, 3). they describe the thallus as being slightly clubshaped, in which the wall of the axial cavity is not always clearly visible. in specimens which show a broad axial cavity, they supposed that calcification did not extend to the wall of the central cell. they also mention that all specimens with a narrow central cavity (i.e. the fully calcified envelope) show three rows of branches, the primaries always being large. as a result of incomplete calcification of the primary branches, the inner wall may exhibit a toothed appearance, originally named intusannulation. in the authors’ opinion, it cannot be ascribed to the alternation of calcified and noncalcified whorls of primary branches, as was put forward by pia (1920). intusannulation: the usage of the therm “intusannulation”, which is mentioned by all authors and in all hitherto described species as a generic characteristic, seems to be rather vague, regarding both its appearance and the way it is manifested and its origin. this may be concluded from many examples, of which i shall cite the following: intusannulation was first mentioned by pia (1912, p. 36) in the description of g y r o p o r e l l a ampleforata gümbel and represented by broadenings in the inner side of the “skeleton” (i.e. calcareous envelope). later pia (1920, p. 168) interpreted the intusannulation in g. ampleforata as a result of incomplete calcification at irregular intervals along the axial cavity, whereas in p. mediterraneus he regarded it as being produced by an alternating succession of calcified and non-calcified whorls. at the same time, pia (1920) established d i p l o p o r a p h a n e r o s p o r a which shows a regular alternation of swellings and constrictions in its interior cavity and in which the inner morphology is basically of different origin and accordingly should be treated separately. hurka (1967), interpreted the intusannulation in physoporella intusannulata as a regular succession of swellings and constrictions of the inner cavity. kochansky-devidé (1970), in the description of gyroporella intusannulata , emphasised the irregularity of intusannulation, as shown by irregularly shaped (variously deep and variously broad) swellings and variously prominent and irregularly toothed constrictions of the axial cavity. bassoullet et al. (1977, p. 160) mention “internal joints” or intusannulation and emphasize that it can be used as an additional detail in the description but cannot have species-specific taxonomic validity. as already mentioned above, barattolo et al. (1994), in analysing p. mediterraneus , suppose that intusannulation occurs in specimens with a broad axial cavity as a result of incomplete calcification of the primary fig. 1 general position of the localities: 1) mali alan; 2) jadiëevac. 137sokaë: lower and middle liassic calcareous algae (dasycladales)... fig. 2 geological column of the liassic deposits of the mali alan and jadiëevac localities (velebit mt.). legend: 1) stromatolites; 2) bioturbations; 3) peritidal breccia; 4) peloids and intraclasts; 5) dasycladal algae; 6) bivalve lithiotis problematica; 7) oncoids; 8) ooids; 9) bioclasts; vt 26 sample with algae from the mali alan locality; jd 4-17 samples with algae from the jadiëevac locality. 138 geologia croatica 54/2 branches, i.e., when the calcification does not extend to the wall of the central cell. for the intusannulation in p. barrabei lebouché & lemoine (which they transferred to the genus eodasycladus), barattolo et al. (1994) stated that it could be more or less pronounced or totally absent, manifesting itself as a regular alternation of swellings and constrictions of the axial cavity and producing a wavy appearance in longitudinal sections. from this it is clear that two different cases are manifestly ascribed to the same phenomenon. berger & kaever (1992, p. 10, fig 2.1e), while discussing the posible cause and origin and the shapes of that phenomenon, stated that it could show regular or irregular arrangement and could be used in defining a species, and that it deserves further study. finally, de castro (1997, p. 187) defines the phenomenon as follows: “articulation characterised by the alternation of swellings and constrictions, along the inner surface of the skeleton, due to the different extent of calcification of the proximal lateral portions”. in an attempt to analyse this phenomenon, the following question arises: is it of primary or of secondary origin? from all that has been mentioned in the above review, it could be concluded that it is primary in all those cases in which (a) it is the result of incomplete calcification, or (b) the calcification was of varying extent, or (c) it might be environmentally induced. barattolo et al. (1994), in the caption of their pl. 1, fig 4, state: “...where the stem wall is still preserved but primary branches are obliterated by the intusannulation”, which may mean that intusannulation may be regarded as a secondary process. in addition to the above examples, visually similar phenomena may be observed, e.g., in praturlonella salernitana b a r a ttolo, in which there is no thinning of the wall between the consecutive whorls (barattolo, 1978, pl. 13, fig. 4) and no intusannulation is mentioned in the original description. similarly, in w i n d o s o p o r e l l a r a d i a t a mamet & rudloff, praturlonella nerae (dragastan et al.) bucur, and in the form ascribed by soka» & veli∆ (1978, pl. 1, fig. 3), to selliporella donzellii sartoni & crescenti, there is a more or less pronounced inner wavy surface. in those three forms, neither a change in wall thickness nor a pronounced toothed surface is visible, which would otherwise suggest reduced or variously extended calcification, so that the origin of that phenomenon, which may or may not occur in specimens of the same species and in the same population, remains totally obscure. in some species, e.g. diplopora phanerospora , it is probably a genetic character. however, what emerges from the above review is, that features occurring on the inner wall, which may display similar or different shapes and be of the same or different origin, have been lumped together under the label of “intusannulation”. this may be justified if it is regarded only as a morphological feature. however, because this phenomenon may be more or less pronounced or even totally absent, within a species, it cannot be used as a species-specific, or, even less so, generic diagnostic taxonomic criterion. morphological variants morphological variants: in the hitherto published papers, p. mediterraneus has been figured many times. most of the published photomicrographs included more or less well preserved, often apparently heterogeneous material, without its having been analysed in more detail or mutually compared. in the material from mali alan pass, mt. velebit, the observed variability comprises a broad array of different morphological details, occurring within one contemporaneous population thriving in the same habitat. these facts facilitated a new and more complete description of p. mediterra neus, which, to my mind, comprises a group of individuals with rather varying morphology and appearance, connected with transitional or intermediate forms or showing a gradual change in individual morphological characters in one specimen. the intention of this paper is to illustrate the abundant new material and thus to show the newly observed characters of individual morphological elements, their variability and interrelationships, and to explain the differing views with regard to the origin of individual morphological characters. d e s c r i p t i o n : palaeodasycladus mediterraneus ( p i a ) includes specimens with a mostly cylindrical thallus (pl. i, figs. 2, 5; pl. ii, fig. 3; pl. iii, figs. 1-2 and others). the thallus is only seldom slightly club-shaped, i.e., its diameter slightly increases upwards; thus the thallus has no stalk and no “head” (pl. i, fig.1). numerous specimens in the population show greatly varying dimensions. if specimens with a longer thallus are preserved, the thallus is often bent (pl. ii, fig.3), which is supposed to be the result of water currents, or, alternatively, due to gravitation. the outer surface is, in general, smooth and even, perforated by circular, elliptical or polygonal pores of distal branches (pl. i, fig 5; pl. ii, fig.1). only rare specimens show a slightly undulated outer surface (pl. iii, fig. 5). some specimens show, on their outer surface, more or less broad or narrow fissures, arranged at regular, or, more often, irregular intervals. the depth of the fissures varies towards the centre of the skeleton resulting in the appearance of shallow, narrow and irregular annulation (pl. iii, figs. 2, 7). observations on numerous specimens reveal a primarily smooth and even inner surface along the central cavity; it is preserved in about 60% of observed specimens; in the others, it is more or less destroyed. the degree of destruction may vary: the walls of the primary and secondary branches may be destroyed, producing an enormously and anomalously broad central cavity (pl. iii, fig.5), or the inner wall and part of the calcareous partitions between the primary branches may be destroyed, so that the remaining parts are visible, in longitudinal section, as shorter or longer, obliquely situated, symmetrical bars (pl. iv, fig. 5), or else only the inner wall at the base of the branches may be destroyed, whereas the pores of the primaries remain 139sokaë: lower and middle liassic calcareous algae (dasycladales)... completely preserved (pl. vi, fig. 4; pl. vii, fig. 6). there are specimens which show, mostly in their lower and middle parts, completely preserved inner structures (the wall of the main cell, primary and secondary branches), but, in the upper part (where the primaries are, as a rule, larger), only a part, or nothing at all, of the inner wall and the primaries may be visible, depending on the extent of the destruction (pl. iv, fig. 6 part; pl. v, fig. 4). this differ to barattolo et al. (1994) in that the degree of preservation of the inner structures is regarded as being purely the result of subsequent, more or less intense, destruction, rather than being insufficient calcification. therefore a secondary, subsequent process occurs during, and is dependent upon diagenesis and, consequently, cannot be labelled intusannulation, and, of more practical importance, cannot be regarded as a species-specific characteristic. indeed, the extent of the destruction depends to a large degree on the dimensions (i.e., the diameter) and the shape of the primaries and on their being more or less densely arranged: the destruction is stronger and more frequent in specimens, or in parts of the specimens, having large, swollen primaries, arranged in densely packed whorls, in which the calcareous partitions between the branches and the whorls become excessively thin which is, in general, more often the case in the upper part of the thallus (pl. iv, fig. 1, upper part). in those observed specimens in which the inner wall is preserved, the central cavity occupies in general 2030% of the entire diameter, rarely amounting to 40%. already pia (1920) noted that the branches ramify further and that three orders of ramifications may be distinguished. also, the branches may be more or less steeply inclined with regard to the longitudinal axis of growth; in some specimens they are more steeply inclined in the upper parts of the thallus, but they are never, in this species, perpendicular to the thallus, as incorrectly stated by deloffre & laadila (1990). some specimens, e.g. the sections illustrated by barattolo et al. (1994, pl. 1, figs. 2, 4) and in pl. xi, fig. 1 below, even indicate the possibility of having four orders of branches. this depends on whether the shorter or longer, finger-like protrusions which grow out of the primary branches without basal constrictions will be regarded as a separate order of branches or not. pia (1920) also mentions the possibility that ramifications in the basal part of the thallus may show a lesser degree of branching, which is also indicated in pl. iii, fig. 7 below, though we still lack a unique specimen (section) in which the transition from a lower to higher degree of branching would be visible. primary branches are arranged in clear whorls. in consecutive whorls they are positioned one above the other, thus forming vertical rows (pl. i, fig. 5; pl. v, fig. 5; pl. x, fig. 6), though this arrangement may be disturbed, coming closer to an alternating position. neighbouring whorls may be either tightly packed, separated by only thin calcareous partitions (pl. iv, figs. 4-5; pl. v, figs. 3, 5), or else spaced further apart from each other and separated by thick calcareous mass (pl. iii, fig. 1; pl. vi, fig. 1; pl. vii, figs. 6-8). primary branches may exhibit various shapes, which, together with different types of secondary branching, the equally varying shapes of the secondary branches, and variable distance between the whorls, gives the impression of dealing with taxonomically heterogeneous material (fig. 3). according to the available material (which comprises several thousand variously orientated sections), the primary branches are, as a rule, large, with minor exceptions, and may be cylindrical (tubular) or sausage-shaped (pl. vi, fig. 1), coneshaped, i.e., distally tapered (pl. v, figs. 2-3), or very rarely completely irregular (pl. v, fig. 1; pl. viii, fig. 2). the larger the primary branches (i.e., the greater their diameter) the tighter the package of the whorls and the thinner the calcareous partitions between the whorls, which are thus prone to destruction (pl. i, fig. 5; pl. iv, figs. 4-5). in some specimens, the primary branches increase in diameter going upwards (pl. iv, fig. 1); simultaneously, calcareous partitions become thinner and therefore more easily destroyed (pl. iv, fig. 1). some sections show a more pronounced change in the shape of the primary branches (pl. iv, fig. 1; pl. v, fig. 4) and some primaries show even a higher degree of branching than the rest; thus, the same specimen show both 3rd and 4th order of ramifications (pl. i, fig 2; pl. xi, fig. 1). the number of primary branches in a whorl (previously an unknown criterion) varies from 12 to 18. from the distal surfaces, or distal points, depending on how the terminations of primary branches are shaped, several secondaries grow out, their number varying from 3 to 8. in specimens with tapered (coneshaped) terminations of the primaries, the secondaries seem to grow out from one place (pl. v, figs. 2-3) and in such cases their number seems to be restricted to 3-5 (pl. i, figs. 3-4). in such cases, when the secondary branches are tightly compressed at the base, they form a bundle (pl. i, figs. 2-5; pl. iii, fig. 1; pl. xiv, fig. 7) while diverging distally. the secondaries may be either constricted at their bases (pl. ii, fig. 3; pl. vi, figs. 14) or may form finger-shaped protrusions growing out of the primaries (b a r a t t o l o et al., 1994, pl. 1, fig. 4; pl. iii, fig. 4, and pl. v, fig. 2, this paper). secondaries also vary in their length and thickness, being of phloiophorous or acrophorous shape (pl. i, figs. 2-5; pl. v, fig. 2; pl. vi, figs. 1-4). in some specimens, the secondaries show constrictions, giving a beaded (pl. xiii, fig. 3) or seemingly articulated appearance (pl. ii, fig. 3; pl. vi, fig. 3; pl. xiii, figs. 1-2). from the distal ends of the secondaries, the clearly phloiophorous tertiaries emerge; from their distal ends they seem to go through the outer rim of the skeleton (calcareous envelope) and therefore more or less widened, funnel-shaped, tubules (pl. i, fig. 3; pl. xi, figs. 1, 6-8, 13), or, sometimes, a dark, micritized layer surrounding (enveloping) the surface of the skeleton (pl. i, fig. 3; pl. vii, 140 geologia croatica 54/2 fig. 3 schematic review of sections of possible forms of branches in palaeodasycladus mediterraneus var. mediterraneus. fig. 3; pl. xi, figs. 8-11) is visible on the outer rim. the number of tertiaries on a secondary branch varies depending on their shape: from 2-3 when the tertiaries are distinctly swollen to 4 when they are smaller and of slightly increasing diameter distally. such branches are said to show characteristic multiple constrictions which gives an articulated appearance. in the available material this can be seen in a small number of specimens (pl. iv, fig. 6; pl. xiii, figs. 1-2), in which, also, unambiguous distinction between the secondaries and the ter141sokaë: lower and middle liassic calcareous algae (dasycladales)... tiaries appears exceedingly difficult. specimens with bundles of short phloiophorous branches with no visible constrictions are much more numerous (pl. v, fig. 3; pl. xi, figs. 1, 6-8, 13). the shape of the pores of the most distal branches on the outer surface of the skeleton varies from circular-elliptical to tightly compressed, polygonal. because of the variability in the shape and dimensions of branches, tangential sections or those in which only the thirdand fourth-order branches (if developed) are preserved, are not suitable for determination. the long-held assumption of cladospority has been confirmed, in the available material, by cysts being found in the cavities of the primary branches (pl. i, fig. 5; pl. xiv, fig. 1). sporadically, single cysts may be found within the secondary and even tertiary branches. these occurrences of cysts question the interpretation (b a r a t t o l o et al., 1994, pl. 1, figs. 1, 3) of rounded and elongated structures, situated in the interior of branches of some rare specimens, as being cladosporous reproductive organs. on the basis of their shape, arrangement, their mutual relationships, and frequency of occurrence, i am inclined to assume that those features possibly develop as results of some differences during the process of calcification. the available material contains specimens that, at first glance, give a visually heterogeneous impression and, when compared with each other, appear rather distinctly different. this impression of heterogeneity is the consequence of varying thallus size and individual parameters (table 1): shape, size, arrangement and density of primary branches; mode of growth, shape, size, and number of secondary and tertiary branches; and general degree of ramification. however, many of these differences are frequently observed in the same specimen, which implies their genetic homogeneity, and, besides, there exist intermediary forms which morphologically connect various, visually different specimens. therefore they have all been grouped together into one taxonomic unit. the comparatively abundant and seemingly lavish photomicrographs are deemed necessary to demonstrate the above conclusion, i.e., to show the broad array of morphological variability in this form. even so, however, it should be emphasised that the morphological variability in the photomicrographs presented is not exhaustive for either this species or other species of that genus. stratigraphic position: the species is distributed throughout the southern tethyan realm, and is particularly frequent in the peri-mediterranean region. the compound (synthetic) stratigraphic range of the species corresponds to the lower and middle liassic. palaeodasycladus mediterraneus var . heraki (soka» & nikler, 1966) n. comb . pl. vii, figs. 1-2, 4; pl. ix, fig. 4; pl. xii, fig. 1; pl. xiv, figs. 5-6; pl. xv, fig. 2; fig. 4.1 1966 petrascula heraki n. sp. soka» & nikler, p. 7-8, fig. 1b. trnovski gozd mali alan jadiëevac maximum observed length of thallus l 21.60 15.34 18.76 outer thallus diameter d 1.16 3.38 1.12 3.15 1.93 5.40 inner thallus diameter d 0.24 0.58 0.24 0.64 0.48 0.76 relation d/d 0.164 0.282 0.142 0.335 0.124 0.333 distance between whorls h 0.16 0.44 0.20 0.49 0.39 0.49 diameter of primaries p 0.06 0.24 0.08 0.35 0.10 0.34 length of primaries l 0.20 0.72 0.15 0.60 0.30 0.49 number of primaries in a whorl w 12 18 12 18 12 18 diameter of secondaries p’ 0.10 0.15 0.05 0.20 0.09 0.20 length of secondaries l’ 0.30 0.60 0.14 1.12 0.25 0.86 number of secondaries on a primary w’ 3 5 3 5 (up to 8) 3 4 diameter of tertiaries p’’ 0.08 0.26 0.05 0.20 0.16 0.25 length of tertiaries l’’ 0.14 0.34 0.08 0.30 0.20 0.45 number of tertiaries on a secondary w’’ 3 4 2 4 3 4 angle of inclination of branches α < 70o < 70o < 70o table 1 comparison of principal biometric parameters of specimens belonging to p. mediterraneus (pia) var. mediterraneus from three distant localities (all dimensions in mm). 142 geologia croatica 54/2 1969 petrascula heraki soka» & nikler soka» & nikler, p. 103-112, pl. fig. 1, non figs. 2-3; pl. 2, fig. 6, non figs. 1-5; pl. 3, non figs. 1-2, 4. non 1996 p e t r a s c u l a ?h e r a k i soka» & nikler barattolo & bigozzi, pl. 54, fig. 7. the remains of this alga were first briefly described by soka» & nikler (1966) as petrascula heraki n. s p . afterwards, a more detailed description with illustrations followed later by soka» & nikler (1969). however, both descriptions were laden with errors, in that heterogeneous material was amalgamated. due to poor preservation it was possible only to assume the existence of trichophorous tertiary branches serving as assimilators. later on, this uncertain taxonomic position and inadequately known characters led bassoullet et al. (1978) to consider the form as a possible synonym of fanesella dolomitica cros & lemoine. the presently available material, with more numerous and better preserved sections, enabled the redetermination of the form as p. mediterraneus (pia) var. he r a k i (soka» & nikler) n. comb. the main characteristics of this variety are as follows: the rectangular shape of the primary branches, which are situated slightly obliquely (up to 25°to the growth axis), though this angle may vary on the same specimen (pl. vii, figs. 2, 4). the thallus is cylindrical, supposedly with a slightly club-shaped termination. the outer surface sometimes appears to be slightly wavy (pl. xiv, fig. 6) and clearly delineated, whereas the inner surface is more often partly destroyed. primary branches are basically rectangular, sometimes slightly deformed and, occasionally, distally slightly widened (fig. 4.1). they are tightly packed both within a whorl and with the respect to the arrangement of whorls. both the whorls and the branches within a whorl are separated by thin calcareous partitions which are prone to destruction. secondary branches grow out of the distal end of the primaries, either in bundles or singly. the secondaries are somewhat shorter than the primaries and of slightly phloiophorous or acrophorous shape (pl. vii, figs. 1-2; pl. xiv, fig. 5; pl. xv, fig. 2). sporadic constrictions of the secondaries cannot be ruled out, though this was not clearly observed. the tertiaries, though poorly visible, are certainly present. they are short and grow out of the outer terminals of the secondaries (pl. vii, fig. 1). they are supposed to be phloiophorous, numbering 3-4? (table 2). single cysts in the cavities of the primaries indicate the cladosporous type of reproduction in this variety (pl. iv, fig. 4). some specimens may show some intermediate characters, transitional to another variety, p. mediterraneus (pia) var. i l l y r i c u s (soka» & nikler) n. comb., or another species, palaeodasycladus anae (soka») n. comb. the main distinguishing characteristic of this variety, particularly with regard to the type-variety, is the square or rectangular shape of the primary branches due to their dense packing within a whorl and the equally dense arrangement of consecutive whorls, that are separated by thin calcareous partitions, which is almost never seen in the type variety. further more, while the primary and secondary branches in this variety are approximately of the same length, the tertiaries are, as a rule, much shorter, as distinct from the type variety in which these relationships are highly variable. also, the constrictions and swellings of secondaries and/or tertiaries are rarely, or never, seen in the variety, whereas they frequently occur in the type variety, in which quaternary branches also occur. admittedly, the distinguishing characteristics of the variety, with regard to both type variety and other varieties, are clearly seen in figmaximum observed length of thallus l 9.10 outer thallus diameter d 1.20 2.66 inner thallus diameter d 0.24 0.49 relation d/d 0.177 0.300 distance between whorls h 0.24 0.48 diameter of primaries p 0.19 0.48 length of primaries l 0.25 0.58 number of primaries in a whorl w 12 16 diameter of secondaries p’ 0.04 0.10 length of secondaries l’ 0.20 0.54 number of secondaries on a primary w’ 5 8 diameter of tertiaries p’’ 0.05 0.07 length of tertiaries l’’ 0.10 0.29 number of tertiaries on a secondary w’’ 3-4? angle of inclination of primaries α < 25o table 2 main biometric parameters of p. medi terraneus var. heraki (soka» & nikler) n. comb. (all dimensions in mm). some values, such as p or l, may vary in the same specimen. 143sokaë: lower and middle liassic calcareous algae (dasycladales)... fig. 4 schematic review of sections of some forms of branches in: 1) palaeodasycladus mediterraneus var. heraki; 2) p. mediterraneus var. illyricus; 3) p. mediterraneus var. gracilis (3.a: after cros & lemoine, 1967); 4) p. mediterraneus var. elongatulus. 144 geologia croatica 54/2 ures of thin-sections, and more easily understood than through written description. therefore, the intention to more clearly emphasize only some more prominent morphological differences in individual specimens derived from the same or contemporary populations in order to avoid misidentification of species, is reflected in the taxonomic rank proposed. stratigraphic position: this variety has been found on several localities on mt. velebit and seems to be restricted, so far, to the lower liassic deposits. palaeodasycladus mediterraneus var. illyricus (soka» & nikler, 1966) n. comb. pl. vi, figs. 7-8; pl. ix, figs. 2-3, 5-7, 9-10; fig. 4.2 1966 petrascula illyrica n. sp. soka» & nikler, p. 7-8, fig. 1c. 1969 petrascula illyrica soka» & nikler soka» & nikler, p. 103-109, pl. iv, figs. 1-4; pl. v, figs. 2-4, ?5, non fig. 1; pl. vi, figs. 1-2. this form has also been previously described (soka» & nikler, 1966, 1969), but because of insufficiently known characters it was erroneously assigned to the genus p e t r a s c u l a and labelled p. illyrica soka» & nikler. subsequent analysis based on new finds enabled its reinterpretation and assignment to the genus p a l a e o d a s y c l a d u s . the available material, primarily from the mali alan locality, mt. velebit, shows some specific characteristics (the shape of the primary branches) but also some similarities with p. mediterraneus (pia) var. m e d i t e r r a n e u s and also, by the intermediate shape of some branches in some sections, with p. medi terraneus (pia) var. heraki n. var. this new variety p. m e d i t e r r a n e u s (pia) var. i l l y r i c u s (soka» & nikler) n. comb. is proposed to include forms with elliptical or bubble-shaped primaries (pl. ix, figs. 2, 6) as well as those with more or less regularly spherical or nodular primaries (pl. ix, figs 5, 6; pl. vi, figs. 7-8), indicating a group of forms with closely similar though not fully identical, primary branches (fig. 4.2). the thallus is cylindrical, perhaps slightly club-shaped, with a sharp outer surface and clearly delineated, uninterrupted, central cavity (pl. ix, figs. 5-6, 9). the axial cavity occupies 25-33% of the outer diameter (table 3). primary branches are arranged in whorls, consecutive whorls being situated approximately one above the other, thus forming more or less regular vertical rows (pl. vi, fig. 8; pl. ix, fig. 3). the density of whorls varies from specimen to specimen, though, generally, they are more widely spaced than in p. mediterraneus var. hera ki. secondary branches, 3-5, or occasionally even 6-7 in number, grow out of the distal end of the primaries, and are clearly grouped into bundles at their base, while diverging distally. they are mostly acrophorous or slightly phloiophorous, either finger-shaped or constricted at their base. there are several (3-4?) tertiaries growing out from the distal end of the secondaries, which confirms the supposition of bassoullet et al. (1978) about their existence. the tertiaries are phloiophorous, shorter than the secondaries, and, as distinct from the type-variety, do not show any constriction or apparent articulation (fig. 4.2). the existence of specimens with branches of intermediate characteristics on parts of the thallus, transitional to other previously described varieties, may question the justification for the varieties. however, the maximum observed length of thallus l 9.60 outer thallus diameter d 1.45 2.32 inner thallus diameter d 0.40 0.64 relation d/d 0.234 0.331 distance between whorls h 0.30 0.39 diameter of primaries p 0.12 0.24 length of primaries l 0.20 0.36 number of primaries in a whorl w 12 16 diameter of secondaries p’ 0.07 0.12 length of secondaries l’ 0.17 0.34 number of secondaries on a primary w’ 3 5 diameter of tertiaries p’’ 0.05 0.08 length of tertiaries l’’ 0.14 0.24 number of tertiaries on a secondary w’’ 3 4 angle of inclination of primaries α < 20o table 3 main biometrical parameters of p . m e d i t e r r a n e u s var. illyricus (soka» & nikler) n. comb. (all dimensions in mm). 145sokaë: lower and middle liassic calcareous algae (dasycladales)... very pronounced extreme differences, which significantly influence the general appearance of individual specimens, seem to justify their distinction and separation, admittedly at the lowest taxonomic level, in order to emphasize the total variability of the species. stratigraphic position: this variety, too, has been found at several localities (mali alan pass, veliko rujno, duπice, etc.) in the lower liassic deposits of mt. velebit. palaeodasycladus mediterraneus var. gracilis (cros & lemoine, 1967 ex granier & deloffre, 1993) n. stat. pl. xii, part. fig. 6; pl. xvi-xvii, pl. xviii, figs. 1-8; fig. 4.3 selected synonymy: 1967 palaeodasycladus gracilis n. sp. cros & lemoine, p. 251-253, pl. 1, figs. 2-3, 7, non fig. 4. 1975 linoporella buseri sp. nov. radoi»i∆, p. 277-278, fig. 1a-c. 1993 palaeodasycladus gracilis cros & lemoine granier & deloffre, p. 37. 1996 palaeodasycladus gracilis cros & lemoine barattolo & bigozzi, pl. 54, figs. 1, 5 (oblique section, top), ?figs. 2, 5 (oblique section, bottom), ?non fig. 4. as shown in the synonymy, this form has been variously taxonomically treated. recently, it was discussed by several researchers, e.g.: deloffre & laadila (1990), granier & deloffre (1993), barattolo et al. (1994), barattolo & b i g o z z i ( 1 9 9 6 ) . granier & deloffre (1993) performed its formal validation, according to the nomenclatorial rules, but without questioning the justification of its original erection. they also neglected, for formal reasons, the previously established form labelled p a l a e o d a s y c l a d u s m e d i t e r r a n e u s (pia) var. e l o n g a t u l u s p r a t u r l o n, 1966, for which no type-specimen was originally designated (p r a t u r l o n, 1966, fig. 1). barattolo et al. (1994) reviewed the taxonomic treatment of this form, originally described as p . gracilis cros & lemoine, and synonymised it with p. mediterraneus var. elongatulus p r a t u r l o n. they also stressed the controversial status of that form, which, in their opinion, cannot be considered as a variety or a subspecies of p. mediterraneus and, therefore, further investigation was needed in order to tell whether it was an independent taxon or a morphotype of the type-species. despite similarities with p. mediterraneus , the species was originally (cros & lemoine, 1967) dis tinguished from it by having thinner branches, a slender cylindrical skeleton, and, as it was generally thought, often visible intusannulation which, however, may be poorly developed or even absent in the same specimen. the main error originating with the original description, was the synonymising of the form with p . m e d i t e r r a n e u s var. e l o n g a t u l u s and the incorrect assignment of the illustrated sections by cros & lemoine, (1967, pl. 1, figs. 2-4, 7), giving rise to some characteristic features, e.g. for example, the alleged intusannulation. however, the quoted sections, when compared mutually, show different characters. thus, the specimen figured by granier & deloffre (1993) in their pl. 1, fig. 2, and designated as a lectotype, shows fine, thin primaries only in the lower part, whereas in the upper part there are cavities in the skeleton considered to represent intusannulation. however, these should be regarded as destroyed primary branches. in addition, there are evidently phloiophorous secondaries and tertiaries in the top part. that specimen, as well as the one figured in their pl. 1, fig. 7 probably belongs to specimens of p. mediterraneus in which the shape and the dimensions of the primaries change within the thallus. by its general characteristics the specimen figured in their pl. 1, fig. 4. certainly belongs to p . m e d i t e r r a n e u s . the exceptions in the description of that form represent the sections illustrated by barattolo & b i g o z z i (1996, pl. 54, fig. 1 and the oblique section in fig. 5, top), whereas other sections (pl. 54, figs. 2, 4, and 5, bottom) should be excluded from considerations, due to their secondarily enlarged axial cavity which destroyed the primary branches and thus fully obliterated their shape and dimensions. this form is generally identical with p. mediterra neus var. mediterraneus in having a cylindrical (or, perhaps, slightly club-shaped) thallus and three orders of branches with a clear euspondyl arrangement of the primaries, but differs from other morphologically heterogeneous forms of p. mediterraneus on a subspecies level by its thin and slender branches (fig. 4.3), both the first-order and the higher-order ones. the primaries are regularly narrowly tubular (pl. xvi, figs. 4, 7; pl. xvii, figs. 2, 7-8), almost ideally acrophorous, and bear three to four (never more than four) secondaries, their diameter being half that of the primaries (pl. xvi, figs. 3-4, 7; pl. xvii, fig. 8). the tertiaries, probably no more than three, grow out of the top of the secondaries (fig. 4.3). the inner cavity is clearly and sharply delineated with visible entrance of the primaries into the central cavity (barattolo & b i g o z z i, 1966, pl. 54, fig. 1 and pl. 16, figs. 4, 7-8; pl. xvii, figs. 3, 5, 8 this paper) and with no signs of intusannulation. the primaries are very steeply directed upwards, the angle between the primaries and the horizontal plane (α) amounting to 60-70° (table 4). the secondaries generally retain the same inclination. the unequivocal general similarity between this from and the type-subspecies (variety), represented by 146 geologia croatica 54/2 heterogeneous material, makes its separation and differentiation as an independent species, as proposed by cros & lemoine (1967), rather doubtful. contrary to the opinion of barattolo et al. (1994), there seems to be no reason to exclude the form from the morphological range of p. mediterraneus. the afore mentioned visual differences only seem to justify its determination at sub-species level, i.e., as p a l a e o d a s y cladus mediterraneus var. g r a c i l i s (cros & lemoine, 1967 ex granier & deloffre, 1993) n. stat. an additional fact supporting the separation of the variety is that it occurs in the same samples with welldeveloped specimens of the type variety, without observable intermediate forms (though they probably exist). as already mentioned above, the level of separation, however, may appear questionable. the separation at the variety level is suggested by the following: its main characteristic feature is the shape of the branches, which are shown to be a widely variable feature in the species, and therefore the establishment of a separate species would not seem justified. alternatively, the designation of that form as a morphotype, as proposed by barattolo et al. (1994) as a possible solution, seems insufficient to emphasize its clear differences to the type-variety. stratigraphic position: in the peri-mediterranean area, the occurrence of the alga are referred to as being of lower and middle liassic age. the position of algalbearing samples and fossil assemblages in the liassic columns of both mt. velebit and mt. trnovski grozd supports this age. r e m a r k s : as can be seen from the above synonymy list, linoporella buseri radoi»i∆ (radoi»i∆, 1975, fig. 1a-c) is considered to be synonymous with that variety. l. buseri, as noted by b a s s o u l l e t at al. (1978, p. 147), is characterised by three orders of branches, which are not characteristic of the genus l i n o p o r e l l a . in the holotype (r a d o i » i ∆, 1975, fig. 1a, upper left part), the slight constrictions and swellings of the secondary branches can be seen (although not very clearly), as well as their branching into the sligthly phloiophorous tertiaries. the method of emergence of the secondaries, their grouping into bundles prior to their divergence toward the outer end, is the same as in some varieties of p. mediterraneus as described herein. the subsequently figured material (b a ssoullet et al., 1978, pl. 17, fig. 12), which is said to belong to radoiëiê’s original material, shows visible intusannulation, perpendicularly situated branches, and consecutive whorls further apart from each other, all of which clearly indicates that it belongs to p. barrabei . this, together with the possibility of some morphological and biometric parameters variation, unequivocally justifies the assignment of l. buseri to p a l a e o d a s y c l a dus mediterraneus , most probably to the variety g r a c i l i s as stated here, primarily because of the fine, tubular branches (acrophorous, with slightly phloiophorous tertiaries). palaeodasycladus mediterraneus var. elongatulus praturlon, 1966 pl. xviii, figs. 9-12; pl. xix-xxi; fig. 4.4 selected synonymy: 1966 palaeodasycladus mediterraneus (pia) e l o n g a tulus n. var. praturlon, p. 169-170, fig. 1. maximum observed length of thallus l 7.12 outer thallus diameter d 0.63 1.15 inner thallus diameter d 0.24 0.38 relation d/d 0.250 0.444 distance between whorls h 0.20 0.44 diameter of primaries p 0.05 0.10 length of primaries l 0.24 0.48 number of primaries in a whorl w 11 14 diameter of secondaries p’ 0.03 0.04 length of secondaries l’ 0.24 0.48 number of secondaries on a primary w’ 3 4? diameter of tertiaries p’’ ? length of tertiaries l’’ ? number of tertiaries on a secondary w’’ ? angle of inclination of primaries α 60-70° table 4 main biometrical parameters of p . mediterraneus var. gracilis (cros & lemoine) n. stat. (all dimensions in mm). 147sokaë: lower and middle liassic calcareous algae (dasycladales)... 1967 teutloporella elongatula (praturlon, 1966) soka» & nikler soka» & nikler, p. 111-116, pl. i-iv, part. pl. vi. 1972 palaeodasycladus elongatula p r a t u r l o n , 1966 deloffre, p. 109-119, non pl. i, non pl. ii. 1994 palaeodasycladus gracilis cros & lemoine 1967 ex granier & deloffre, 1993 (= p . m e d i t e r r a n e u s var. e l o n g a t u l u s p r a t u r l o n , 1966) barattolo et al., p. 1-2, 6-7. 1996 palaeodasycladus gracilis cros & lemoine 1967 ex granier & deloffre (= p a l a e o dasycladus mediterraneus var. e l o n g a t u l u s praturlon) barattolo & bigozzi, p. 205, pl. 54, figs. 1, 5 oblique section top, ?figs. 2, 4 and fig. 5 bottom. lectotype: praturlon (1966, fig. 1), oblique section, situated diagonally in upper left part of the photo. this form, originally described by p r a t u r l o n (1966) as a variety of p. mediterraneus , was subsequently variously treated, but until recently it was given priority with respect to p. gracilis , with which it is synonymous. barattolo et al. (1994) more extensively discussed the taxonomic position and the relationships of this form to similar ones, and concluded that this form (which lost its priority) was identical to p . g r a c i l i s , or, according to the above, p. mediterraneus var. g r a c i l i s , respectively. the omission of designating the type-specimen (type-section) in the “group photograph” (praturlon, 1966, fig. 1) had the regrettable consequential loss of validity for purely formal reasons (according to i.c.b.n. rules), which led granier & deloffre (1993) to quote it as p. mediterraneus var. elongatulus praturlon 1966, nom. nud. the justification for separation of the variety is not an issue, and it would also resolve the apparent taxon v e r s u s m o r p h otype dilemma posed by barattolo et al. (1994). therefore it is proposed here, in order to formally validate the variety, to select the oblique section situated diagonally in the upper left part of fig. 1 in praturlon (1966) as the type-section, or lectotype. praturlon (1966) diagnosed the new variety as having a broad axial cavity and numerous thin, long, and dense branches situated almost parallel to the longitudinal axis of the thallus. the assimilatory filaments never widen distally; on the contrary, they seem to be trichophorous. praturlon (op. cit.) also mentioned the typical intusannulation. the revalidation of the taxon has been attempted by d e l o f f r e (1972). he elevated it to the rank of species, but since none of his depicted sections (d el o f f r e, 1972, pl. 1, figs. 1-5; pl. 2, figs. 1-6) belong to this variety but rather represent p. mediterraneus , a new description, comparison, and illustrations are required. d e s c r i p t i o n : the calcareous skeleton, of generally cylindrical shape, consists of numerous, upwardly bent, deeply concave, calcareous rings. individual rings are shaped like deep funnels, deeply inserted and tightly squeezed one into another; therefore no annular cavities between individual rings exist; only in their proximal parts (near the central cavity) do they appear as thin fissures, visible in tangential and oblique sections (pl. xviii, figs. 11-12; pl. xix, figs. 2-3, 5-6). specimens with very clearly developed annulations (see pl. xx, fig. 9), are extremely rare. the outer surface has a feathery (plicate) surface, due to very steep distal parts of individual rings, which are almost parallel to the growth axis (pl. xviii, figs. 11-12; pl. xix, figs. 1-3). it is characterised by more or less clear, slightly swollen folds, each fold corresponding to one ring (pl. xviii, fig. 11; pl. xix, fig. 6). the broad axial cavity, occupying up to 30% of the outer diameter, is the result of partial (pl. xx, figs. 2-6) or complete (pl. xix, fig. 1; pl. xx, figs. 4-7) destruction of the primary branches. primary branches are elongated, cylindrical or irregularly globular in shape, more or less obliquely situated and directed upwards (pl. xix, figs. 1, 4-5; pl. xx, fig. 2). in some specimens they may be more strongly bent in their distal ends, from where the secondaries emerge in a finger-like manner, without visible constrictions at the base. the finger-shaped secondaries quickly taper or give rise to thin, tubular, tertiary branches, which are even more steeply inclined upwards, and, in extreme cases, become parallel to the growth axis (fig. 4.4). some specimens suggest the possible occurrence of fourth-order branches. the number of secondaries is usually three, more rarely four (table 5; pl. xviii, fig. 9; pl. xix, fig. 2; pl. xx, fig. 6). in this variety the secondaries and the tertiaries do not show any constrictions and swellings, which would give an impression of their being articulated. they are entirely acrophorous; nor do they show any distal widenings, as distinct from p. mediterraneus var. medi t e r r a n e u s , which is characterised by phloiophorous branches. in their uncalcified parts, functioning as an assimilatory device, they perhaps assume a trichophorous shape. the exact point of bifurcation, as well as a clear distinction between the secondaries and tertiaries, is difficult to determine because they have approximately the same thickness (diameter) and cross each other in thin sections. the longest secondary branch observed reached 5.9 mm (pl. xviii, fig. 10). similarities and differences: with regard to p . mediterraneus , basic similarities include: the basic morphology, the arrangement and mode of ramification of the branches, and the shape of the thallus. differences from the type form are as follows: p. mediterraneus var. e l o n g a t u l u s has only two types of primary branches, elongated cylindrical ones and others which are irregularly swollen (e.g. some kind of a globular type). in this variety, the secondaries and the tertiaries never 148 geologia croatica 54/2 show a seemingly articulated appearance, nor do they exhibit distal swellings, as distinct from the typical variety which always shows typically phloiophorous branches. in p. mediterraneus var. elongatulus they are distinctly acrophorous. the thallus of this variety is, in fact, annulated, but the annular depressions are mostly obliterated by calcareous rings being tightly squeezed together, or they may be partly preserved in the cortical part of the skeleton. in the type variety, the angle between the secondaries and the horizontal plane does not exceed 70°, whereas in this variety it may reach, in extreme cases, 90° whereby the secondaries become extremely long. this variety has a more massive skeleton than p. mediterraneus var. gracilis and a secondarily widened axial cavity, due to the destruction of large primary branches. in p. mediterraneus var. g r a c i l i s t h e primaries are either tubular, without a pronounced swelling near the axial cavity, or there is a slightly pronounced widening from which 2 or 3 secondaries immediately grow out. in such cases, the proximal swelling may be functionally regarded as being a primary branch, though visually giving the impression of metaspondility. because of the shape and small diameter of the primaries, the central cavity in p. mediterra n e u s var. g r a c i l i s is clearly delineated and only very rarely secondarily enlarged, as distinct from this variety. in both varieties the branches are directed steeply upwards, but whereas in p. mediterraneus var. g r a c i l i s it is the primaries, in this variety the secondaries distally bend up and become even more steeply directed upwards, becoming longer and, in extreme cases, parallel to the thallus. in p. mediterraneus var. g r a c i l i s , the distance between the consecutive whorls is larger and more clearly expressed than in this variety (due to larger primaries in the latter). some specimens of p. medi t e r r a n e u s var. g r a c i l i s show slight distal broadening of the secondaries, whereby the secondaries gradually acquire a slightly phloiophorous shape (pl. xvi, fig. 1), which has never been observed in this variety. however, it is sometimes difficult to avoid the question of which are the real, relevant, differences between the two varieties, though the differences clearly exist in a visual comparison. therefore, this together with the differently shaped thallus (cylindrical or seemingly cylindrical), and the folded (plicate) outer surface resulting from original annulation (which is not of decisive significance), differentiation at the lowest taxonomic level would seem to be the most appropriate solution. stratigraphic position: in the original description (p r a t u r l o n, 1966), the most common stratigraphic position of this alga is in the orbitopsella praecursor subzone, or in the lower part of the l i t h i o t i s f a c i e s , respectively, which should indicate, according to p r at u r l o n (1966), a middle upper liassic age. subsequent synonymyzing of this variety with p . m e d i t e r r a neus var. gracilis (especially in absence of photographic illustrations) prohibits an unequivocal conclusion as to which one of the varieties is questionable, and therefore casts doubt on a reliable stratigraphic position. while the first finds of the alga in mt. velebit, quoted under the name teutloporella elongatula (p r a t u rl o n), come from an identical stratigraphic level and are accompanied by a very simmilar middle liassic fossil assemblage as that from the type locality, the newly recovered sample vt-26 indicates its occurrence in the lower liassic. therefore, the total stratigraphic range of the alga is lower -middle liassic. maximum observed length of thallus l 13.46 outer thallus diameter d 1.45 3.96 inner thallus diameter d 0.38 0.98 relation d/d 0.141 0.266 distance between whorls h 0.30 0.58 diameter of primaries p 0.12 0.40 length of primaries l 0.39 0.72 number of primaries in a whorl w ? diameter of secondaries p’ 0.04 0.10 length of secondaries l’ ≤ 5.9 number of secondaries on a primary w’ 3 4 diameter of tertiaries p’’ 0.04 length of tertiaries l’’ ? number of tertiaries on a secondary w’’ ? angle of inclination of primaries α ≤ 50° angle of inclination of secondaries α’ ≤ 90° table 5 main biometrical parameters of p . mediterraneus var. elongatulus p r a t u rlon (all dimensions in mm). 149sokaë: lower and middle liassic calcareous algae (dasycladales)... palaeodasycladus mediterraneus var. calciticus n. var. pls. xxxi-xxxii origin of the name: after well developed calcitic partitions of variable thickness, well visible in variously oriented sections. type locality: mt. velebit, on the sv. rok o b r o v a c road, approximately 100 m from the milestone on mali alan pass, in the direction of obrovac. greenwich coordinates: 44° 17’ 24” n, 15° 39’ 23” e. type stratum: well-bedded, grey, lower liassic ( h e t t a n g i an lower sinemurian) limestones, represented by the alternation of skeletal-intraclastic grainstone and mudstone (micrite), with sporadically developed stromatolitic laminae. depositional environment was probably shallow subtidal with periodic emersions into the vadose zone. h o l o t y p e : oblique section figured in pl. xxxi, fig. 3, slide vt-26/379, deposited, together with illustrated paratype-material, at the institute of geology, zagreb. d i a g n o s i s : being almost identical to the type variety by its main biological and morphological characteristics, this new variety is distinguished by its peculiarly developed skeleton, consisting of tightly squeezed calcareous tubules, enveloping each primary and secondary branch. the calcareous wall is irregular and of variable thickness, more pronounced toward the distal end, comprising irregular calcitic partitions, the shape and thickness of which are defined by the cavities between the branches. in tangential section, the calcareous tubes vary in shape from rectangular to polygonal. d e s c r i p t i o n : the cylindrical thallus is composed of tightly packed tubular calcareous envelopes around the branches; arranged in whorls and slightly inclined upwards, situated around the elongated central cavity. the inner cavity is originally more or less straight or with shallow depressions where the branches enter the central cavity. in such cases the inner cavity becomes slightly irregular, but always remains clearly delineated (pl. xxxi, fig. 8; pl. xxxii, fig. 8). however, the inner side of the calcareous wall, around the central cavity, is often destroyed and therefore, the central cavity is secondarily broadened (pl. xxxi, fig 4; pl. xxxii, fig. 4), comprising 20-35% of the total diameter (table 6). the outer surface is seldom even (pl. xxxi, fig. 3; pl. xxxii, fig. 4); instead it is more often indented, due to destruction (erosion) of the outer ends of the calcareous envelopes (pl. xxxi, figs. 4, 7). the main visual characteristic of the species is brought out by the irregularly and unevenly thickened walls of the branch envelopes, which then appear in sections as heavily calcified partitions. branches are tripartite, as in some other species or variety of the genus and each primary branch, together with its secondary and tertiaries, is situated within its own calcareous envelope. the euspondyl arrangement of branches is defined by the equally radial arrangement of tubular envelopes. the envelopes may be perpendicular to the growth axis, or, more frequently, are inclined by a small angle and directed slightly upwards (pl. xxxi, figs. 3, 8). three to four secondary branches grow out from the distal ends of the primaries; however, because of poor calcification, the secondaries are not easily observable (pl. xxxi, fig. 3; pl. xxxii, fig. 7). the secondaries remain tightly pressed together within the calcareous envelope; they do not have calcified walls of their own. additional calcification may maximum observed length of thallus l 7.70 outer thallus diameter d 2.40 3.88 inner thallus diameter d 0.48 1.00 relation d/d 0.187 0.258 distance between whorls h 0.20 0.40 diameter of primaries p 0.16 0.24 length of primaries l 0.38 0.48 number of primaries in a whorl w ? diameter of secondary p’ 0.10 0.12 length of secondary l’ 0.30 0.48 number of secondary on a primary w’ 3 5 diameter of tertiaries p’’ 0.06 0.09 length of tertiaries l’’ 0.20 0.40 number of tertiaries on a secondary w’’ ?3 4 angle of inclination of branches α 0 15 table 6 main biometrical parameters of palaeo dasycladus mediterraneus var. calciticus n . var. (all dimensions in mm). 150 geologia croatica 54/2 develop between the secondary but without being in contact with the envelope, e.g. a type of hanging calcification. the tubular envelopes are densely packed and remain in mutual contact both within a whorl and with those of the neighbouring whorls. therefore the walls of consecutive envelopes merge together into a common recrystallised calcitic envelope and their individual existence can be only rarely observed (pl. xxxi, fig. 3). the tertiary branches are not visible in the material available; only an indication of their existence can be sporadically observed (pl. xxxi, figs. 3, 8; pl. xxxii, figs. 3, 7). in tangential sections, the envelopes appear as irregular rectangular or polygonal contours (pl. xxxi, fig. 3; pl. xxxii, fig. 7). this variety, too, is possibly cladosporous. similarities and differences: main characteristics: tripartite branches, euspondyl arrangement of primary branches, relation between the outer and inner diameters, cladosporous reproduction, etc. are typical of and define the generic assignment of the variety. the main characteristic feature which distinguishes p. mediterra neus (pia, 1920) 1927 var. c a l c i t i c u s from any other variety of the species is the existence of visually conspicuous calcitic partition walls of the branches, which form the calcareous skeleton of the thallus. in contrast to other p a l a e o d a s y c l a d u s -species, and their varieties in which the branches grow through the calcareous mass of the skeleton, either all along their length or only as secondary and tertiary branches, in p. mediter raneus var. c a l c i t i c u s the branches, including the secondary and tertiary ones, remain uncalcified within their tubular envelopes. therefore the secondaries and tertiaries of this variety remain grouped together (pl. xxxii, fig. 7), whereas the porous appearance, typical of other p a l a e o d a s y c l a d u s species, is either undeveloped, or barely discernible. stratigraphic position: p. mediterraneus (pia, 1920) 1927 var. c a l c i t i c u s occurs in the rich algal assemblage of sample vt-26, which contains p. mediterraneus (pia, 1920) with several varieties, p. dolomiticus (cros & lemoine) n. comb., p. barrabei l e b o uché & lemoine, eodasycladus ogilviae cros & lemoine, and others; some of them prove the lower liassic age of the deposits. the position of the fossiliferous sample vt-26 in the stratigraphic column of upper triassic dolomites and lower liassic limestones, also including the first occurrence of a middle liassic foraminiferal assemblage, is shown in fig. 2. remarks on the taxonomic classification of newly established varieties the study of rich lower and middle liassic algal assemblages has provided new data, in addition to that previously known regarding the visible variability of taxa. variously orientated sections of both the type species of p a l a e o d a s y c l a d u s and other taxa of that genus show a broad array of morphological modifications, which, at first sight, give the impression of heterogeneous material which initially did not obviously belong to a single species. only after a detailed study of numerous sections from one or more samples taken from the same bed, was it possible to imply the existence of contemporaneous populations derived from the same habitat (or, in cases of transported material, from several neighbouring habitats), and obtain an insight into the degree of gradual variations. these variations are manifested by the increase of the total volume of primary branches from the bottom to the top of the thallus, the variability in the shape of branches, changes in the degree of total branching orders, and varying length, method of growth, and inclination of primary, secondary and tertiary branches. all these changes can occur either in the same specimen or in related specimens of the same population. besides, specimens occur that appear to be completely irregular, and that diverge from any group united by common characters. these specimens could only be conceived as deviants from the development of individual specimens within a species or a variety, respectively (pl. v, fig. 1; pl. viii, fig. 2). in contrast, other specimens were observed, in which some characteristic feature (e.g., square or bubble-shaped primary branches) was more pronounced than in others, and which, then, also according to other characteristics, could be united into smaller groups. these groups could be identified, more or less reliably, and distinguished from the type species or other species of the same genus. the existence of specimens with intermediate/transitional characteristics, results in the formation of a continuous series with the type species at one end, and culminating at the other with a group of specimens with most strongly pronounced differences with regard to the type species or its type variety. such relationships, including both observable differences and similarities, require a somewhat different approach to taxonomic interpretation. as has been already indicated, the lack of clear, valid, and generally adopted criteria of taxonomic classification in green calcareous algae means that, in such cases, every attempt of taxonomic differentiation bears the signature of a more or less subjective opinion of the author in question. thus the main questions are: whether to carry out such a classification and at what level, e.g. genus, species or variety, and where, when, and how to fix the taxonomic boundaries, which would be subjective anyway but at least recognisable to some extent. the existence of specimens which show different morphologic features on different parts of the thallus, or a series of specimens with gradual transitions, raises the question as to the justifiability of their taxonomic separation, more so as all these changes may occur simultaneously. in contrast, there are extreme cases with strongly differing characteristics resulting in the clearly different general visual appearance of individual specimens which forces distinction between them, even if the separation is carried out at the lowest taxonomic level, in order to elucidate the 151sokaë: lower and middle liassic calcareous algae (dasycladales)... total range of variation within the species and to reduce the possibility of incorrect species identification. therefore it is not viable to accept the species, or the variety, as an individual with sharply delimited characteristics; instead it should be considered that a group of individuals share some common characteristics whereas other characteristics may vary to a greater or lesser extent. thus the same species, or variety, may sometimes include visually rather different specimens. the separation of varieties within the palaeodasycladus mediter r a n e u s group of species, on the basis of more or less convincing arguments, is the most convenient taxonomic approach to this data. these varieties can be distinguished, then, in spite of varying biometrical parameters, mostly on the basis of visual appearance and overall impression acquired from the study of numerous sections in extremely rich material. distinguishing characteristics of the established varieties the distinguishing of the established varieties must be based on some pronounced morphological characteristics rather than on biometrical parameters, which are very variable and hence inconclusive, as can be seen from table 7. there follow short descriptions of the established varieties, with emphasis on differential characteristics that cannot be elucidated from the tabulated numerical values. palaeodasycladus mediterraneus (pia, 1920) 1927 var. mediterraneus t h a l l u s : cylindrical to slightly club-shaped, sometimes with visible transverse fissures in the skeleton; dimensions highly variable (d varying in relation 1:5). primary branches: essentially tubular, or modified from a tubular shape, sometimes phloiophorous/clubshaped, sporadically ramified into two approximately equal branches, often varying in shape and, generally, increasing in volume toward the top parts of the thallus. secondary branches: more strongly phloiophorous, in general longer than the primaries, sometimes with one or two constrictions, growing out of either a constricted base, or finger-like, without basal constrictions. tertiary branches: clearly phloiophorous, arranged in bundles, usually shorter, seldom longer than the secondaries; in the latter case always with several constrictions, which gives an articulated appearance. on the outer surface, pores are large, circular to polygonal in outline. inclination: primary branches always clearly inclined, up to an angle (α) of 70°. r a m i f i c a t i o n : up to third, sometimes to fourth-order branches. p. mediterraneus p. mediterraneus p. mediterraneus p. mediterraneus p. mediterraneus p. mediterraneus var. mediterraneus var. heraki var. illyricus var. gracilis var. elongatulus var. calciticus l 21.60 9.10 9.60 7.12 13.46 7.70 d 1.12 5.40 1.20 2.66 1.45 2.32 0.63 1.15 1.45 3.96 2.40 3.88 d 0.24 0.76 0.24 0.49 0.40 0.64 0.24 0.38 0.38 0.98 0.48 1.00 d/d 0.124 0.335 0.177 0.300 0.234 0.331 0.250 0.444 0.141 0.266 0.187 0.258 h 0.16 0.49 0.24 0.48 0.30 0.39 0.20 0.44 0.30 0.58 0.20 0.40 p 0.06 0.35 0.19 0.48 0.12 0.24 0.05 0.10 0.12 0.40 0.16 0.24 l 0.15 0.72 0.25 0.58 0.20 0.36 0.24 0.48 0.39 0.72 0.38 0.48 w 12 18 12 16 12 16 11 14 ? ? p’ 0.05 0.20 0.04 0.10 0.07 0.12 0.03 0.04 0.04 0.10 0.10 0.12 l’ 0.14 1.12 0.20 0.54 0.17 0.34 0.24 0.48 ≤ 5.9 0.30 0.48 w’ 3 5 5 8 3 5 3 4? 3 4 3 5 p’’ 0.05 0.26 0.05 0.07 0.05 0.08 ? 0.04 0.06 0.09 l’’ 0.08 0.45 0.10 0.29 0.14 0.24 ? ? 0.20 0.40 w’’ 3 4 3 3 4 ? ? ?3 4 α < 70o < 25o < 20o 60 70° ≤ 50o 0 15o table 7 comparative table of biometric parameters of the newly established varieties of palaeodasycladus mediterraneus (pia) (all dimensions in mm). 152 geologia croatica 54/2 palaeodasycladus mediterraneus var. heraki (soka» & nikler, 1966) n. comb. t h a l l u s : predominantly cylindrical; dimensions variable (d varying in relation 1:2). primary branches: distinctly rectangular, densely packed both within whorls and with densely arranged consecutive whorls separated by thin calcareous partitions. secondary branches: phloiophorous, approximately of the same length as the primaries, sometimes slightly swollen and constricted, giving a bumpy but never a seemingly articulated appearance; growing out of one or several places at the distal surface of a primary branch. tertiary branches are, as a rule, clearly phloiophorous and half as long as the secondaries. i n c l i n a t i o n : primary branches have a low inclination angle (α), up to 25°, which is also the lower inclination limit of the type variety. ramification: up to the third order. palaeodasycladus mediterraneus var. illyricus (soka» & nikler, 1966) n. comb. t h a l l u s : predominantly cylindrical; dimensions variable (d varying in relation approximately 1:1.5). primary branches: bulbous, bubble-shaped or irregularly elliptic; whorls distinctly set apart from each other, preventing the branches of neighbouring whorls (and, most frequently, also the branches within a whorl) from mutually touching. secondary branches: phloiophorous, approximately of the same length as the primaries, lacking any swellings and constrictions. tertiary branches: phloiophorous, visibly shorter than both the primaries and the secondaries. i n c l i n a t i o n of primary branches (α) reaching up to 20°. ramification: up to third order. palaeodasycladus mediterraneus var. gracilis (cros & lemoine, 1967 ex granier & deloffre, 1993) n. stat. t h a l l u s : cylindrical; dimensions variable (d varying in relation up to 1:2). primary branches: of two types; the first type being represented by poorly visible small irregular widenings arranged in a regular manner along the axial cavity, and giving rise to secondary branches. the second type is represented by slightly phloiophorous or, more often, elongated tubular branches (acrophorous type). secondary branches: as a rule, predominantly acrophorous, longer than, and half the diameter of, the primaries. exceptionally, and only in intermediate specimens, they may acquire a slightly phloiophorous shape. tertiary branches: in the available material, they are not easily observed. inclination: primary branches of the tubular or slightly phloiophorous shape (second type) are inclined under an angle (α) of 60-70°. ramification: up to third order. palaeodasycladus mediterraneus var. elongatulus praturlon, 1966 t h a l l u s : cylindrical (d varying in relation 1:2), with more or less clearly pronounced annulation becoming indistinct due to mutual contact of steeply inclined calcareous rings (segments), producing feather-like incisions on the outer surface. primary branches: more or less irregular, bulbous or cylindrical. each calcareous ring bears one row of primary branches, which are always more or less steeply inclined and bent upwards. secondary branches: very thin, with slightly widened proximal parts (acrophorous type); going outward they bend steeply upwards and, most frequently become almost parallel to the longitudinal growth axis. tertiary branches: the existence and branching of tertiary branches are difficult to discern because of long and mutually intersecting secondary branches and therefore their characteristic features cannot be defined. i n c l i n a t i o n of primary branches (α) up to 50°. the most distinguishing feature is the extremely steep inclination of the secondary branches, reaching up to 90°. ramification: up to third order. palaeodasycladus mediterraneus var. calciticus n. var. t h a l l u s : cylindrical, consisting of tightly squeezed and compressed, mutually connected, tubular calcareous envelopes around each branch. this gives a pecu153sokaë: lower and middle liassic calcareous algae (dasycladales)... liar and easily distinguishable appearance to this variety, with clearly visible calcitic bars between the neighbouring whorls. primary branches: essentially cylindrical, elongated, sometimes irregular in shape. secondary branches: growing out either fingerlike, or with a constricted base; of the same length as, or more frequently longer than the primaries, due to varying diameter giving bumpy appearance. the bundle of secondaries belonging to a primary branch is situated within a tubular calcareous envelope, which is internally slightly or only partially calcified (in the gaps between the branches), and secondaries are, therefore, in general, poorly visible. tertiary branches: phloiophorous, short, poorly visible, due to insufficient calcification. i n c l i n a t i o n : primary branches, each within its own calcareous envelope, are slightly inclined (0-15°). ramification: up to third order. palaeodasycladus barrabei lebouché & lemoine, 1963 ex granier & deloffre, 1993 pl. xiv, part. fig. 8, pls. xxii-xxiv; pl. xxxviii, figs. 1-3; fig. 5.1 selected synonymy: 1963 palaeodasycladus barrabei n. sp. lebouché & lemoine, p. 95, 97, 99; pl. 3, figs. 1-7. 1970 palaeodasycladus barrabei lebouché & lemoine bouroullec & deloffre, p. 88-90; pl. 5, figs. 1-2, ?figs. 3, 6-8, non fig. 5; pl. 6, ?figs. 1-2, 7, non figs. 3-6. 1978 palaeodasycladus barrabei lebouché & lemoine -bassoullet et al., p. 187-191, pl. 22, figs. 1-4. 1990 palaeodasycladus barrabei lebouché & lemoine granier & deloffre, p. 36. 1994 eodasycladus barrabei (lebouché & lemoine, 1963 ex granier & deloffre, 1993) nov. comb. barattolo, de castro & parente, p. 4-6, pl. 2, figs. 1-3, 6-8, ?4-5. the original description (lebouché & lemoine, 1963) was accompanied by several illustrations of sections: pl. 3, figs. 1-7; out of which figs. 1-4 cannot be assigned with certainty to this species. this species was not frequently mentioned and even more rarely illustrated. due to a lack of good sections it remained inadequately known, with controversial and/or uncertain taxonomic attribution. in their revision of the genus p a l a e o d a s y c l a d u s , deloffre & laadila ( 1 9 9 0 ) are of the opinion that it should be considered a younger synonym of p. mediterraneus . however g r a n i e r & deloffre (1990), in their critical inventory of the fossil dasycladales (part ii), amend the non existence of the holotype by selecting a lectotype and thus validate the species. barattolo et al. (1994), based on the material from the type-locality, give an emended diagnosis of the species, emphasising that some specimens show strongly swollen individual secondaries, with considerably larger diameter than the remaining branches of the same bundle, whereas other specimens develop rounded pores which may be interpreted as being choristosporous reproductive organs. they also mention that each secondary branch bears four tertiaries, characterised by three segments separated by clearly pronounced constrictions. the outermost articles possibly form an enveloping crust. in addition to characteristics mentioned by l e b o u c hé & lemoi n e (1963), barattolo et al. (1994) particularly discuss the intusannulation and the more or less pronounced undulation of the outer surface. they also decided to transfer this form into the genus e o d a s y c l a d u s, primarily because an individual secondary branch may be more strongly swollen than its neighbours in the same bundle, or because of the occurrence of larger, more or less rounded pores which were assigned to bubble-shaped structures and interpreted as choristosporous reproductive organs. this means, however, that the most numerous specimens (at least in this study) which do not show any swollen secondaries or large pores assigned to choristosporous reproductive organs, were neglected. besides, in assigning p. barrabei to the genus e o d a s y c l a d u s, barattolo et al. (1994) leave unresolved the relationship between this form and eodasycladus ogilviae. they only pose the question of e. ogilviae perhaps being the younger synonym of p . barrabei . they suggest a possible solution by statistical comparison of biometric parameters of the two forms, based on an abundant material, though the values of individual parameters fall within the variation range of individual species (see table in barattolo et al., 1994). however, in the original description of the genus eodasycladus (cros & lemoine, 1966), the authors emphasise the distinction between the new genus and p a l a e o d a s y c l a d u s as being the existence of fertile secondary branches in e o d a s y c l a d u s. in the description of the species (e. ogilviae), cros & lemoine (1966) point out the unequivocal similarity of their sections with p. barrabei , but they also note the important differences in detail. these differences enable the distinction of three forms, which might be classified as three species belonging to two or three genera. cros & lemoine (1966) also put forth the supposition of their having to deal with different parts of the same plant and thus their description consists of three parts 154 geologia croatica 54/2 fig. 5 schematic review of sections of branches in: 1) palaeodasycladus barrabei (1.a: after lebouché & lemoine, 1963); 2) p. alanen sis; 3) p. benceki; 4) p. dolomiticus (4.a: after cros & lemoine, 1966; 4.b: after barattolo & bigozzi, 1996). 155sokaë: lower and middle liassic calcareous algae (dasycladales)... which correspond to three types of organisation, which may be regarded as three developmental stages of the same species. while describing the three types within eodasycladus ogilviae , they emphasise the similarity of their first two types with palaeodasycladus barrabei , whereas the third type is distinguished by having one of the secondary branches more strongly swollen than the others and functioning, probably, as a sporangium. because it could be established with certainty that we are not dealing with different parts of the same plant with three types of organisation, nor with three different stages of the same species, it appears necessary to give a more complete description of a great majority of the available specimens, which would correspond to the original description of p. barrabei . d e s c r i p t i o n : palaeodasycladus barrabei l e b ouché & lemoine has a cylindrical to slightly clubshaped (pl. xxii, fig. 1), sometimes slightly bent (pl. xxii, fig. 2) thallus. the outer surface of the calcareous skeleton (envelope) may show different degree of segmentation, ranging from undulation (pl. xxii, fig. 1) to shallow fissuration (pl. xxii, fig. 3; pl. xxiii, fig. 8) to clearly expressed annulation (pl. xxiii, figs. 1, 4, 9, 11-12). therefore it is not surprising that l ebouché & lemoine (1963), in their original description of p. barrabei , fail to mention any outer annulation, as well as in the first type of e. ogilviae ( w h i c h are, in fact, identical forms), whereas cros & lemoine (1966) note, in the second type, a slight outer annulation producing the appearance of successive articles like a string of barrels. on the other hand, barattolo et al. (1994), in their amended diagnosis mention the outer annulation but note that this feature may be obliterated or totally destroyed by micritisation and abrasion. the inner cavity is characterised by intusannulation, which is agreed by all authors regardless of whether both species, p. barrabei and e. ogilviae, or only p. barrabei , are considered. intusannulation corresponds to the originally described type (pia, 1912), in which it is featured by regular narrowings and widenings of the inner cavity, which may be clearly visible (pl. xxii, fig. 4; pl. xxiii, figs. 1-2, 11) or else only indicated (pl. xxiii, figs. 3, 7), or the inner cavity may have almost even rims (pl. xxii, figs. 1-2). the relationship between intusannulation and the outer annulation in the third type of e. ogilviae has been described in detail by both cros & lemoine (1966) and barattolo et al. (1944), in their completion of the description of p. barrabei . arrangement of the branches: the tripartite branches (fig. 5.1) are arranged in clear, rather spaciously separated whorls. each whorl corresponds to a segment, regardless of whether the segmentation is indicated by shallow depressions (undulation) or clear annulation, which, in some cases, may reach the wall of the central cavity (pl. xxiii, figs. 4, 9, 11). in specimens with clearly developed annulation, the primary branches may be seen to enter the central cavity immediately below the tooth-like protrusion of the inner wall, directed toward the centre of the inner cavity (pl. xxii, fig. 4; pl. xxiii, fig. 1). the primaries are generally small, of varying shape (as in the type-species) ranging from short tubular (or rod-like) (pl. xxii, fig. 4; pl. xxiii, fig. 1) to short, slightly club-shaped (pl. xxii, figs. 23), to stump-like or almost bubble-shaped (pl. xxiv, fig. 1). in some specimens, some primaries branch off immediately after leaving the central cavity, one directed upwards, the other downwards, which produces a seemingly metaspondyl appearance (pl. xxii, figs. 4, 7). in some cases, there is an impression of dealing with neighbouring branches of a whorl, of which one is directed upwards, the other downwards. if this is true, then the pores of the primaries within a segment would be arranged in two rows and in alternating position. the position of the primaries has so far always been considered to be perpendicular to the longitudinal axis of growth, but they can also be directed slightly upwards, the maximum angle with the horizontal plane (α) amounting to 30° (table 8; pl. xxiii, figs. 1-3). depending on the inclination of the primaries and the succession of the secondaries, the ring-shaped depressions in specimens with annulation may be positioned either perpendicularly or obliquely to the growth axis, giving the same direction also to the calcareous segments (pl. xxiii, figs. 1, 11). each primary branch bears a bundle of 5-6 secondaries. bundles with more (6-8) secondaries, as mentioned by barattolo et al. (1994), have not been observed, though this does not exclude their existence. secondaries of the same bundle diverge; some are directed upwards, some downwards. secondaries of neighbouring bundles within a whorl cross mutually, which renders it impossible to distinguish bundles in tangential sections. in the analysed material, the secondaries are much more slender and longer than the primaries and they retain the same diameter throughout their length (pl. xxii, figs. 1, 3-4; pl. xxiii, fig. 8). the tertiaries grow out from their ends (pl. xxiii, fig. 8). the number of tertiaries could not be determined with certainty; it is supposed to be 3-4 (for each secondary branch), as it was stated for this species by l ebouché & lemoine (1963) and for e. ogilviae b y cros & lemoine (1966), contrary to what is visible in specimens figured by barattolo et al. (1994, pl. 2, figs. 2-4). articulation of the tertiaries was not apparent, which means that this feature, as well as the more or less pronounced swellings of the secondaries, is an unstable characteristic, which may vary from population to population and from habitat to habitat. the increase of pore diameter in the outer parts of the skeleton suggests a phloiophorous shape of the branches. the reproduction is assumed to be cladosporous; the swellings of some branches (without a fully developed sporangial “bubble”) is regarded as an adaptation necessary for the placement of cysts; owing to this, sterile specimens may also be supposed to exist. 156 geologia croatica 54/2 stratigraphic position: in the original description, lebouché & lemoine (1963) mention the finds of this alga in several levels within the stratigraphic range l o w er middle liassic (lotharingian p l i e n s b a c h i a n ) . r a d o i » i ∆ (1975) ascribes the same stratigraphic range to her finds, whereas b a s s o u l l e t et al. (1978) define the general stratigraphic position of this alga as upper sinemurian. revisiting the type material, b a r a t t o l o et al. (1994) mention only the middle liassic. b a s s o u l l e t (1997, p. 339-341. pl. lxvii) assigns the species, together with some others, to the lower liassic, with its upper limit being below the pliensbachian lower boundary. in mt. velebit, that alga has been found in the rich algal assemblage of the sample vt-26, which comes from the lower liassic. at some other localities in mt. velebit (kubus, jadiëevac, the foothill of mt. crnopac), its stratigraphic position is the same. a few finds are also known from the lower liassic deposits of ivanjica near dubrovnik. taxonomic validation of palaeodasycladus barrabei lebouché & lemoine and its relationship with eodasycladus ogilviae cros & lemoine as mentioned above, p. barrabei has been variously treated taxonomically. after the original description by lebouché & lemoine (1963) it was for some time regarded as valid, until deloffre & laadila (1990), in their revision and emendation of the genus p a l a e o d a s y c l a d u s , expressed the opinion that it should be considered as a younger synonym of p. mediterra n e u s. in the original description of the genus e o d a s y c l a d u s and e. ogilviae, respectively, cros & lemoine (1966) consider the types i and ii to be closely related to p. barrabei , whereas the type iii is distinguished from p. barrabei by having some secondary branches more strongly swollen, and/or larger pores, interpreted as choristosporous reproductive organs. in practice this means that the specimens belonging to types i and ii should be identified as p. barrabei if no specimens of type iii are present, or if they are, then the types i and ii represent sterile specimens of e. ogilviae, respectively. obviously, such a situation was not satisfying, as specimens which evidently belong to the same taxon are treated as belonging to separate taxa, depending on how they occur. because of the existence of individual more strongly swollen branches and/or rounded structures, barattolo et al. (1994) transferred p. barrabei into the genus eodasycladus, emphasising its similarity with e. ogilviae. later, they stress that sterile specimens of p. barrabei show enough differences to p. mediterraneus , which was not questioned by anybody (except, erroneously, by deloffre & laadila, 1990), in spite of the fact that primary branches in p. barrabei may be slightly inclined upwards. in this case, however, we may ask ourselves what had led different authors to include their own, priority-bearing species (p. barrabei ), into the types i and ii as sterile forms of e. ogilviae, as has been done by cros & lemoine (1966), or to transfer into the genus e o d a s y c l a d u s , both those (relatively few) specimens with possible sporangial cavities and the sterile ones, previously described as p. barrabei , as has been done by barattolo et al. (1994). if the above mentioned authors accept the existence of fertile and sterile forms in e. ogilviae, we must ask ourselves why they have not done the same thing in p. barrabei , which should have priority. i agree with barattolo et al. (1994) that the existence of choristosporous reproductive structures, in spite of being only sporadically developed (see reconstruction by cros & lemoine, maximum observed length of thallus l 11.4 outer thallus diameter d 1.20 2.54 inner thallus diameter d 0.34 0.76 relation d/d 0.186 0.331 distance between whorls h 0.48 0.76 diameter of primaries p 0.10 0.20 length of primaries l 0.15 0.24 number of primaries in a whorl w 20 26 diameter of secondary p’ 0.05 0.10 length of secondary l’ 0.20 0.53 number of secondary on a primary w’ 5 8 diameter of tertiaries p’’ 0.05 0.15 length of tertiaries l’’ 0.12 0.48 number of tertiaries on a secondary w’’ 3 4 angle of inclination of branches α < 30 table 8 main biometrical parameters of palaeo dasycladus barrabei lebouché & lemoine (all dimensions in mm). 157sokaë: lower and middle liassic calcareous algae (dasycladales)... 1966, fig. 9) and rarely observed, represents a new quality which, as an extreme consequence, enables the establishment of the new genus. in spite of the obvious close relatedness between p. barrabei and e. ogilviae, which can be discussed within the framework of their phylogenetic relationships, the validity of p. barrabei need not be questioned, the more so because of the strongly pronounced variability of both morphologic features and biometric parameters between the species of that genus. palaeodasycladus alanensis n. sp . pl. xxv; pl. xxxviii, figs. 4-6; fig. 5.2 origin of the name: after mali alan pass, central part of mt. velebit, on the sv. rok obrovac road. type locality: on the sv. rok obrovac road (fig. 7), about 100 m from the milestone on the mali alan pass in the direction of obrovac; co-ordinates: 44° 1 7’ 2 4” n, 15° 3 9’ 3 3” e. regrettably this outcrop is nowadays inaccessible because of unmarked land-mines. type stratum: grey, well-bedded fossiliferous limestone, represented by the alternation of skeletal-intraclastic grainstone and micrite with sporadically developed stromatolitic laminae. the depositional environment was probably shallow subtidal with sporadic emersions into the vadose zone. the algal-bearing samples derive from the well-documented lower liassic deposits within a continuous succession, as shown in the stratigraphic column in fig 2. holotype: oblique section figured in pl. xxv, fig. 1, slide vt-26/149. this slide, as well as others containing the figured material, are stored at the institute of geology, zagreb. d i a g n o s i s : calcareous alga with a cylindrical, undivided, thallus, with slight outer undulation, shallow fissuration and/or partial annulation of the outer surface. inner cavity with well visible but not strongly pronounced intusannulation. the species-specific characteristics are bowl-shaped or irregularly swollen (nodular) primary branches, which, in deep tangential sections, appear as large, rounded to polygonal pores. secondary branches are acrophorous, growing out from the outer margin of bowl-shaped or nodular primaries. phloiophorous tertiary branches are barely visible. d e s c r i p t i o n : the cylindrical calcareous skeleton is characterised by a slightly undulated outer surface and, it seems, irregularly occurring shallow fissuration or annulation (pl. xxv, fig. 5). the inner cavity is clearly delineated, with slight intusannulation, and occupies up to 30% of the whole diameter (table 9). the tripartite branches are arranged in loosely spaced whorls, the distance between the neighbouring whorls being approximately equal to that in p. barra b e i. the primary branch communicates with the inner cavity through a small pore, which is situated on or immediately below the protrusions of the inner wall that make the intusannulation and where the inner diameter is the smallest. the primary branches may have various shapes (fig. 5.2), which may occur in different combinations in the same specimen. in welldeveloped specimens, the primary branches are abruptmaximum observed length of thallus l 8.18 outer thallus diameter d 2.08 3.08 inner thallus diameter (max.) dmax 0.54 0.64 relation dmax/d 0.118 0.302 inner thallus diameter (min.) dmin 0.38 0.54 relation dmin/d 0.123 0.260 distance between whorls h 0.64 0.84 diameter of primaries p 0.30 0.48 length of primaries l 0.20 0.35 number of primaries in a whorl w 0 12 diameter of secondary p’ 0.06 0.12 length of secondary l’ 0.34 0.58 number of secondary on a primary w’ 5 7 (?8) diameter of tertiaries p’’ 0.04 0.10 length of tertiaries l’’ 0.15 0.26 number of tertiaries on a secondary w’’ 3 4 angle of inclination of branches α 0 table 9 main biometrical parameters of palaeo dasycladus alanensis n. sp. (all dimensions in mm). 158 geologia croatica 54/2 ly widened at their very base, whereby they acquire a bowl-like (pl. xxv, figs. 2-3) or nodular-bushy shape (pl. xxv, fig. 4). individual branches on the same specimen may be less well-developed, similar to those in p. barrabei , from which this species is derived. in deeper tangential sections, the primaries appear as rounded to polygonal shaped pores which are in mutual contact both within a whorl and with neighbouring whorls (pl. xxv, figs. 1, 6 top). the secondary branches extend from the margins of the bowl-shaped or nodular primaries, and they diverge from one another (pl. xxv, figs. 1-4). these branches are acrophorous, regardless of their thickness (pl. xxv, fig. 4). the number of secondaries (from available sections in pl. xxv, figs. 1-3, 4), is estimated to be 5-7, possibly 8. neighbouring bundles of the secondaries are not grouped separately, but are in mutual contact. thus one cannot tell which secondary belongs to which primary branch. tertiary branches are visible only with difficulty, because of the worn outer surface (pl. xxv, fig. 4). they seem to be very short. in some pores of the primary branches, single or grouped small, dark, rounded corpuscles can be seen, which are interpreted as possible cysts and which would define the species as being cladosporous. similarities and differences: p a l a e o d a s y c l a d u s a l a n e n s i s n. sp. belongs to the group of p a l a e o d a s y c l a d u s species, which is characterised by having intusannulation and rather loosely spaced whorls. the phyletic connection between p. alanensis and p . b a r r a b e i ( t h e latter being the ancestral form) is shown by the sporadic and irregular occurrence of the b a r r a b e i -type branches (in addition to bowl-shaped or nodular ones) in p. ala n e n s i s. the distinction between p. alanensis and p . barrabei is best illustrated in deeper tangential sections, in which the whorls of primary branches in p. barrabei appear as small pores arranged in rows which are set apart from each other (pl. xxiii, fig. 8), as distinct from p. alanensis in which the pores are large, rounded to polygonal, and in mutual contact (pl. xxv, fig. 1). as regards p. mediterraneus , the main difference concerns the shape of the primary branches and the distance between the consecutive whorls. the same differences exist in relation to p. gracilis and p. illyricus n. sp., as well as being particularly pronounced in p . calciticus n. sp. as regards e. ogilviae, the main difference concerns the shape of the primary and secondary branches: in p. alanensis , cysts develop in the primaries, whereas in e. ogilviae the development of cysts takes place in one of the secondaries, which becomes considerably thicker or even strongly swollen into a “bubble”, thus becoming the choristosporous organ. stratigraphic position: p. alanensis n. sp. occurs in the algal assemblage contained in sample vt-26 which has already been shown in the preceding text to be of early liassic age. palaeodasycladus dolomiticus (cros & lemoine, 1966) n. comb. pls. xxvi-xxvii; fig. 5.4 selected synonymy: 1966 fanesella dolomitica n. sp. cros & lemoine, p. 163-164, pl. 2, figs. 1, 3-4, 5 part. 1969 petrascula heraki soka» & nikler soka» & nikler, p. 104-106, pl. 1, fig. 2, non figs. 1, 3; pl. 2, figs. 1-3, non figs. 4-6; pl. 3, fig. 1, ?fig. 2, non figs. 3-4. 1993 fanesella dolomitica cros & lemoine granier & deloffre, p. 22-23, 30-31. 1996 fanesella dolomitica cros & lemoine barattolo & bigozzi, p. 201-202. 1996 fanesella sokaci n. sp.barattolo & bigozzi, p. 201-205, pl. 45, fig. 2; pls. 51-53. main characteristics of the genus fanesella in the original description of the genus f a n e s e l l a cros & lemoine (1966) emphasise that the genus is characterised by four orders of branches. the primary branches are swollen, functioning as sporangia, and tightly squeezed, arranged in clearly developed whorls. the secondary branches grow out of the primaries like the fingers of a glove, i.e. without constrictions at the base. the thirdand fourth-order branches emerge in bundles, with constrictions at the joints. in the description of the type-species, cros & lemoine (1966) mention that the so-called secondary branches are, in fact, short protrusions of the primaries (fig. 5.4a). in defining the fourth-order branches, however, the authors are not explicit, stating that in one case, when dealing with specimens with a slightly abraded outer surface, they find indications of all branches, whereas later in the text they say that in the majority of cases where the branches are visible, they appear open towards the exterior; meaning that these branches are unequivocal. barattolo & bigozzi (1996) give a summarised diagnosis of the genus f a n e s e l l a , emphasising the difference toward palaeodasycladus as being, mainly, the existence of four orders of branches, as distinct from the three orders in p a l a e o d a s y c l a d u s , and in the primaries being somewhat thicker (fig. 5.4b). comparison of the main characteristics of the genera palaeodasycladus and fanesella and the proposal for their unification the analysis of the abundant available material of p . m e d i t e r r a n e u s shows that some specimens include some characters that served as the basis for distinguishing and establishing the genus fanesella . the rectangu159sokaë: lower and middle liassic calcareous algae (dasycladales)... lar shape of the primary branches is illustrated in several specimens of p. mediterraneus (pl. vi, fig. 3 part; pl. vii, figs. 1-2, 4; pl. ix, fig. 4), as well as the transition from cylindrical and sometimes irregularly shaped to rectangular in the same specimen (pl. v, fig. 4). the finger-like secondaries (i.e. without basal constrictions), which are said to be characteristic of f a n e s e l l a , can also be seen in some specimens of p. medi t e r r a n e u s . it should be stressed, however, that this feature should not be given a particularly strong taxonomic significance. the main diagnostic feature of f a n e s e l l a is said to be the presence of four orders of branches; this feature, however, can also be present (or, at least, cannot be excluded) in some specimens of p. mediter r a n e u s (e.g., pl. 1, fig. 4 in barattolo et al., 1994, in which the finger-like growth of the secondaries can also be clearly seen). specimens similar to the one shown in pl. xi, fig. 1, which can be visually assigned to p. mediterraneus , also show short, delicate protrusions which, according to the criteria adopted, can also be regarded as secondary branches. ramification up to fourth-order branches can occur on individual branches in some whorls in p. barrabei (clearly visible in pl. xxii, figs. 4, 7 and pl. xxiv, fig. 2. this clearly proves the possibility of fourth-order branch development in the genus palaeodasycladus . in specimens with only outer parts of the skeleton, i.e. the area of thirdorder and, possibly, fourth-order branches preserved, we cannot distinguish p . m e d i t e r r a n e u s from p. dolo m i t i c u s specimens. for these reasons the alleged morphological differences between f a n e s e l l a and p a l a e o d a s y c l a d u s are insubstantial and indicate a more comprehensive description of one taxon, i.e. falling within the, admittedly broadened, variation range of the genus p a l a e o d a s y c l a d u s . therefore further retention of the genus fanesella is of no benefit and therefore it is proposed that fanesella be regarded as a younger synonym of palaeodasycladus . d e s c r i p t i o n : p a l a e o d a s y c l a d u s d o l o m i t i c u s ( c r o s & lemoine, 1966) n. comb. is a seldom mentioned, and even more rarely illustrated, species, described from the calcareous lower liassic. it is characterised by a comparatively large, calcareous, cylindrical, sometimes bent, thallus with even outer and inner surfaces. the central cavity occupies 16-32% of the total diameter (table 10). branches are tripartite to quadripartite, depending on how one interprets the morphology of the primary branches. in longitudinal sections, the primary branches are rectangular (pl. xxvii, figs. 2, 5, 7-8), proximally somewhat narrower, while widening distally in transverse sections (pl. xxvi, figs. 5-6; pl. xxvii, fig. 1). they are tightly compressed within a whorl, being mutually separated by thin, regular, calcareous partitions (pl. xxvi, figs. 5-6). between the whorls, these partitions are somewhat more massive and more irregular (pl. xxvii, figs. 2, 5, 7). the primary branches are situated perpendicularly or are slightly inclined to the growth axis, the angle to the horizontal plane usually maximum observed length of thallus l 16.34 outer thallus diameter d 1.94 4.34 inner thallus diameter d 0.48 1.20 relation d/d 0.160 0.321 distance between whorls h 0.40 0.60 diameter of primaries p 0.20 0.48 length of primaries l 0.30 0.85 number of primaries in a whorl w 14 20 diameter of secondary p’ 0.08 0.20 length of secondary l’ 0.14 0.40 number of secondary on a primary w’ 4 5 diameter of tertiaries p’’ 0.06 0.15 length of tertiaries l’’ 0.15 0.38 number of tertiaries on a secondary w’’ 3 4 diameter of quaternaries p’” 0.10 0.15 length of quaternaries l’” 0.10 0.20 number of quaternaries on a tertiary w’” 3 4 angle of inclination of branches α 0 25 table 10 main biometrical parameters of p a l a eodasycladus dolomiticus (cros & lemoine) n. comb. (all dimensions in mm). 160 geologia croatica 54/2 not exceeding 25° (pl. xxvii, fig.8). in some specimens, they are slightly bent in their distal parts (pl. xxvii, fig. 6), which becomes more strongly pronounced in secondary and tertiary branches. the primaries are connected with the central cavity through a somewhat large pore, which is situated in the lower part of the proximal end (pl. xxvii, fig. 8). protrusions similar to fingers of a glove or a cow’s udder grow out of the distal ends of the primaries. these protrusions may be regarded as being either continuations of the primaries or representing the secondary branches. on their distal end, they bear the secondaries or tertiaries, depending on one’s opinion. these, however, are clearly constricted at the base and, as is also the case in some other palaeodasycladus species, may be articulated (pl. xxvii, fig. 6). the fourth-order of branches are seldom clearly visible, as was rightly emphasised in the original description (cros & lemoine, 1966). judging by the shape of the pores in outer parts of the tangential sections, they can be seen to be phloiophorous. in some cases, i.e. in specimens with clearly rectangular primaries, it is difficult to distinguish between p. medi terraneus and p. dolomiticus. in connection with p. dolomiticus, a short comment should be made on the recently described fanesella so k a c i barattolo & b i g o z z i (1996), which is said to differ from p . d o l o m i t i c u s by less massive complete calcification and its considerably larger size. however, because it is well known that the degree of calcification is not a taxonomic character but, most frequently, a consequence of environmental and diagenetic conditions, and larger size can be an extreme value within a variation range (which is perhaps supported by the fact that the finds of p. dolomiticus are still rare and not numerous), it is here proposed that f. sokaci should be considered a younger synonym of p. dolomiticus. as the type species of f a n e s e l l a is herein transferred to p a l a e o d a s y c l a d u s , fanesella anae soka» becomes palaeodasycladus anae (soka») n. comb. stratigraphic position: comparatively rare finds of this alga do not permit a detailed analysis of its stratigraphic range. in the original description, cros & lem o i n e (1966) determine the age of the algal-bearing deposits as sinemurian, s. str. lotharingian. o t t (1974) states it only very generally as lower m i d d l e liassic. barattolo & bigozzi (1996) have discovered this alga, together with tersella genoti a n d numerous p a l a e o d a s y c l a d u s remains, in their microfacies cm3 from the upper part of the calcare massicio fm., which belongs to the sinemurian. b a s s o u l l e t (1997), in his summary review of the most important jurassic dasyclads, also concurs with a sinemurian age. in mt. velebit, it has already been found at the localities duπice and jadiëevac in lower liassic deposits, which is supported by sample vt-26, for which a lower liassic age has been thoroughly documented. palaeodasycladus anae (soka», 1988) n. comb. pl. viii, fig. 1; pl. xiii, figs. 4-5; pls. xxviii-xxx fig. 6 1988 fanesella anae n. sp.soka», p. 9-14, fig. 6; pls. 1-3; pl. 4, figs. 2-4. this species has been recently described and well illustrated (soka», 1988). the description (soka», 1988), as well as the generic assignment, was primarily based on the shape of the primary branches and on the total degree of branching, which may reach third and fourth-order branches, often on the same specimen. in spite of the primaries frequently being of variable shape and often differing one from another in the same specimen, they may, nevertheless, generally be described as being predominantly nodular (pl. xxviii, figs. 1-9; pl. xxx, figs. 1, 3, 5-7). the primaries connect with the central cavity either through a short stalk (pl. xxix, figs. 6-7) or directly through a smaller or larger opening at their base (pl. xxix, figs. 1, 4). species-specific characters concern the distal ends of the primaries which may be variable in the same specimen. sporadically, some branches bear irregular nippleor horn-like protrusions (pl. xxviii, figs. 2, 4-5; pl. xxix, figs. 1, 5, 7). from there, some thin branches grow out, either individually or in bundles, whereas other branches grow out directly from the primary branch, so that the same type of branches may be regarded either as secondary or as tertiary branches (pl. xxviii, fig. 2, top right). in some specimens, primary branches divide halfway along their length into two to three equally strong arms (pl. xxix, fig. 4; pl. xxx, fig. 4), out of which grow thin tertiary branches, which further divide into fourth-order branches that are, undoubtedly, phloiophorous (pl. xxix, fig. 5). in some specimens, some “secondaries” grow like fingers of a glove, as in p. do l o m i t i c u s, or the primary branch has a conical termination and the secondaries grow out sidewise from the primary branch (pl. xxviii, fig. 2, top right). it is difficult to verbally describe every variation and each possible morphological change and furthermore, it is unlikely that such an attempt would yield useful results. the best way to obtain an impression of variability is to illustrate as many differences as possible (pl. xxviii, figs. 1-9; pl. xxix, figs. 1, 4-7; pl. xxx, figs. 4-7). it should, however, be mentioned that no section (specimen) has been observed with all primaries being identical, and not even with all branches ramified to the same degree, which indicates the broad range of variation in the species. the fact that in the some specimens branches may be identical or very similar, by their shape and the degree of ramification, to those in p. me d i t e r r a n e u s ; the fact that the secondaries may emerge from the primaries like fingers on a glove, without basal constrictions, as in p. dolomiticus or in some specimens of p. mediterraneus (which may have four orders 161sokaë: lower and middle liassic calcareous algae (dasycladales)... of branches), and, finally, that both species can show irregular constrictions, narrowings, etc. in the second-, third, and fourth-order branches, suggests their common generic assignment. basically, the main distinction between p. mediterraneus , p. dolomiticus, and p. anae , all three species being of approximately the same dimensions, concerns the different shape of the primary branches, particularly of their distal ends, which can clearly be illustrated: p. mediterraneus (pl. i, fig. 5; pl. vi, figs. 1-3; pl. xxvii, figs. 6-8) vs. p . a n a e ( p l . xxviii, figs. 1-9, pl. xxix, figs 1, 4-7), respectively. p. anae is cladosporous, as are other species of the genus (pl. viii, fig. 1; pl. xiii, fig. 4). as previously mentioned, the similarities outlined above, and even with some details being identical in p . m e d i t e r r a n e u s and p. dolomiticus, this species is also herein proposed to be transferred to the genus palaeodasycladus . the shape, diameter, and length of the firstto fourth-order branches often varies in the same specimen (table 11). for instance, the distance between the consecutive whorls (“h”) in the same specimen varies, in one case, from 0.20 to 0.35, whereas in another case the length of primary branches varies from 0.29 to the extreme value of 0.76 mm. stratigraphic and geographic distribution: t h e species has been found from the central part of mt. velebit (localities: jadovno, duπice, and mali alan pass). the richest sample is vt-26 from the lower liassic, from which it was originally described. palaeodasycladus multiporus n. sp. pls. xxxiii-xxxiv origin of the name: after the numerous pores of the second-order to fourth-order branches. type locality: mt. velebit, about 100 m from the milestone on the mali alan pass in the direction of obrovac, on the sv. fig. 6 schematic review of sections of some possible forms of branches in palaeodasycladus anae. 162 geologia croatica 54/2 r ok obrovac road (fig. 7). coordinates: 44° 1 7’ 2 4” n; 15° 39’ 23” e. t y p e s t r a t u m : grey, well-bedded, lower liassic ( h e t t a n g i an lower sinemurian) limestones, represented by the alternation of skeletal-intraclastic grainstone and micrite, with sporadically developed stromatolitic laminae. the deposits probably originated in a shallow subtidal environment with sporadic emersions into the vadose zone. holotype: oblique section figured in pl. xxxiv, fig. 2, slice vt-26/262, stored, together with illustrated paratypes, in the collection at the institute of geology, zagreb. d i a g n o s i s : cylindrical thallus with euspondyl arranged, more or less inclined and comparatively large primary branches, which give rise to 9-12 finger-shaped secondary branches. tertiary and fourth-order branches are also present. the total number of secondary, tertimaximum observed length of thallus l 12.4 outer thallus diameter d 1.48 2.90 inner thallus diameter d 0.34 0.68 relation d/d 0.149 0.293 distance between whorls h 0.20 0.48 diameter of primaries p 0.15 0.48 length of primaries l 0.20 0.76 number of primaries in a whorl w 12 18? diameter of secondary p’ 0.08 0.20 length of secondary l’ 0.07 0.44 number of secondary on a primary w’ 0 4 diameter of tertiaries p’’ 0.05 0.10 length of tertiaries l’’ 0.20 0.48 number of tertiaries on a secondary w’’ 2 6 diameter of quaternaries p’” 0.03 0.10 length of quaternaries l’” 0.08 0.35 number of quaternaries on a tertiary w’” 2 4 table 11 main biometrical parameters of p a l a eodasycladus anae (soka») n. comb. (all dimensions in mm). fig. 7 map of the mali alan pass area in the south-east mt. velebit, type locality of the sample vt-26. scale 1:25,000. 163sokaë: lower and middle liassic calcareous algae (dasycladales)... ary, and fourth-order branches per primary branch amounts to 70-100 on the outer surface of the thallus. d e s c r i p t i o n : cylindrical, non-segmented, and unbranched thallus often with a clearly delineated outer and inner surfaces. the outer surface is, in some specimens, surrounded by a partly preserved dark rim of probably organogenic micritized matter, formed in the outermost zone of the branches, where they were but weakly calcified (pl. xxxiii, figs. 3, 6; pl. xxxiv, figs. 2-3). the inner cavity has a smooth and even surface and occupies up to 25% of the total diameter. primary branches are generally of a rectangular shape, arranged into comparatively densely packed whorls, and tightly squeezed within a whorl. they are positioned more or less obliquely with relation to the longitudinal growth axis, and directed upwards. the main species-specific characteristic is the large number of secondaries which are finger-shaped and grow out from the distal surface of a primary branch, either from one level (pl. xxxiii, fig. 6; pl. xxxiv, figs. 2-3) or in a more irregular manner (pl. xxxiii, figs. 2, 4; pl. xxxiv, figs. 4-8). the number of secondary branches observed in one plane of section amounts to 6 (pl. xxxiv, fig. 4), which allows for the supposition that at least 9-12 secondaries emerge from the distal end of a primary (table 12). the secondary branches are basically of a phloiophorous type but may be variously shaped, more swollen or more slender. from the distal end of the secondary, a bundle of 3-4 thin, phloiophorous, tertiary branches emerge, which gives a total number of approximately 35-45 tertiaries. fourth-order branches, which in some specimens seem to be very slender and thin, may number 70-100 per primary branch, supposing that each tertiary branch bears 2-3 fourth-order branches. as is also the case in other species of the genus, the distal ends of the primaries may vary in morphological details, and in the shape, length, and mode of emergence of the secondaries. cysts may be occasionally preserved in the pores of the primaries, indicating that the species is cladosporous. similarities and differences: from its basic morphology, including the mode and degree of branching, palaeodasycladus multiporus n. sp. undoubtedly belongs to the broad group of variable forms united in the genus palaeodasycladus . in spite of its general similarity (shape of the thallus existence of tertiary and quaternary branches) with p. mediterraneus (including all its varieties), p. dolomiticus, and p. anae , it differs from all these forms by the larger number of secondary and, especially, tertiary and quaternary branches. because the secondary branches grow out from the entire distal surface of the primaries, in p. multiporus they are not grouped into bundles as in p. mediterraneus (pl. i, figs. 3-5; pl. iii, fig. 1; pl. vi, fig. 6, etc.) or p. anae ( p l . xxx, figs. 1, 2, 4, 6). the large number of distal (?quaternary) branches, which are moreover much finer and incompletely or weakly calcified in the peripheral zone of the thallus, results in the loss of the conspicuous porous structure, well developed in p. mediterrane us and p. dolomiticus and, to a somewhat lesser degree, in p . a n a e . besides, p. multiporus differs from p. anae in the shape of the primary branches, which in p. multi p o r u s remain more or less rectangular, in contrast to p . maximum observed length of thallus l 16.348.18 outer thallus diameter d 1.94 3.20 inner thallus diameter d 0.30 0.68 relation d/d 0.106 0.241 distance between whorls h 0.30 0.48 diameter of primaries p 0.24 0.48 length of primaries l 0.20 0.50 number of primaries in a whorl w ?9 12 diameter of secondary p’ 0.08 0.15 length of secondary l’ 0.20 0.35 number of secondary on a primary w’ 9 12 diameter of tertiaries p’’ 0.04 0.07 length of tertiaries l’’ 0.20 0.35 number of tertiaries on a secondary w’’ 3 4 diameter of fourth-order p’” 0.04 length of fourth-order branch l’” 0.15 0.20 number of fourth-order branch w’” 2 4? angle of inclination of branches α ≤ 30° table 12 main biometrical parameters of p a l a eodasycladus multiporus n. sp. (all dimensions in mm). 164 geologia croatica 54/2 a n a e which is characterised by a broad range of morphological variety in the primaries, which are generally irregular and with nipple-like and irregular fingershaped protrusions which represent the transition to the secondary branches. the rectangular shape of the large primaries is similar in p. multiporus and p. dolomiticus, but in p. dolomiticus there are only 4-5 secondary branches per primary, as distinct from at least 9-12, and possibly even more, in p. multiporus. with regard to p. b a r r a b e i , the obvious difference is in the more densely packed whorls of primary branches in p. multiporus , whereas in p. barrabei they are spaced rather far apart from each other, with a rather high h value. besides, some specimens in p. barrabei may show a more or less pronounced intusannulation and annulation of the skeleton, but this is not a constant feature in p. barra bei. differences between p. multiporus and p. alanensis are similar to those mentioned above; in p. alanensis the primary branches acquire a bowl-like or irregularly bubble-like shape, which in deep tangential sections results in large alternating pores. also, p . a l a n e n s i s may sometimes show intusannulation and annulation, which may be regarded as a distinguishing criterion of secondary importance. with regard to p. calciticus , the main difference is the existence of well-developed calcitic partitions along the thallus and individualised calcitic envelopes in which are situated in all branches issuing from a primary branch in p. calciticus . the difference with regard to p. benceki n. sp. (see below) is obvious, because primary branches in p. benceki a r e enormously large and heavily deformed, with secondary branches growing out not only from the distal surface of the primaries but also from lateral parts, even proximal lateral parts, which is never observed in p . multiporus. stratigraphic position: p. multiporus n. sp. occurs in the algal assemblage contained in sample vt-26, which is of early liassic age. palaeodasycladus benceki n. sp. pls. xxxv-xxxvii; pl. xxxviii, figs. 7-8; fig. 5.3 origin of the name: the species is dedicated to my colleague –uro benëek, the long-serving director of the institute of geology in zagreb, for his significant contribution to the development and affirmation of scientific and publicistic activities in the institute, and, in particular, for his devotion to mt. velebit. type locality: mt. velebit; the locality is approximately 100 m from the milestone on mali alan pass, in the direction of obrovac, on the sv. rok obrovac road (fig. 7); co-ordinates: 44° 17’ 24” n, 15° 39’ 23” e. type stratum: grey, well-bedded lower liassic ( h e t t a n g i an sinemurian) limestone, represented by the alternation of skeletal-intraclastic grainstone and micrite, with sporadically developed stromatolitic laminae. the strata were deposited in a shallow subtidal environment, with temporary emersions into the vadose zone. holotype: oblique section figured in pl. xxxvi, fig. 2, thin section vt-26/436. material containing the holotype and the paratypes figured is stored in the collection of the institute of geology, zagreb. d i a g n o s i s : cylindrical to slightly club-shaped thallus characterised by very large, irregular, and variously shaped primary branches, arranged in clear whorls. the distal surface of the primary branches may be curved or angular, with variously shaped (short, long, thick or thin, straight or curved) protrusions, separated by equally irregular indentations, which gives a completely irregular outline. thin, regular, secondary branches emerge from the distal or lateral surfaces of the primaries and ramify further into the tertiaries near the outer surface. the species is cladosporous. the measured values for p, l, p’ ’, and l’ ’ m a y markedly differ (table 13), even on the same specimen, depending on the shape and the place of emergence of a secondary branch. thus, for instance, those secondaries which grow out from the extreme distal point of a given primary branch may be half as long as those that emerge from the lateral sides of the same primary branch. d e s c r i p t i o n : the calcareous thallus of this species has a cylindrical or slightly club-shaped form, with a gently undulating (pl. xxxv, fig. 2) or shallowly and irregularly annulated outer surface (pl. xxxv, fig. 3). most frequently the outer surface is secondarily abraded and uneven; in some cases, it may be worn down to the distal surfaces of the primary branches (pl. xxxv, fig. 5 part). the inner surface clearly delineates the central cavity; it is even or slightly undulated; intusannulation may be present, but barely visible, representing a relict of its ancestral form. the central cavity occupies approximately 15-30% of the total diameter (table 13). the main characteristic feature of this species is the shape of its primary branches (fig. 5.3). the primaries are arranged in whorls and are in alternating position in neighbouring whorls (pl. xxxv, fig. 6). they are very large, and, in well developed specimens, stretch from the very base, in the direction of growth (pl. xxxv, fig. 1; pl. xxxvii, figs. 4-5), sometimes being of a bushy appearance (pl. xxxv, fig. 2), or irregular in longitudinal and oblique sections, and most frequently elliptical in transverse section (pl. xxxvi, figs. 5-6). variously shaped primaries may sometimes be seen on the same specimen. in some specimens, the extremely large primaries show a strongly irregular outer surface, 165sokaë: lower and middle liassic calcareous algae (dasycladales)... with deep depressions or indentations and shorter or longer bulges, giving, in longitudinal sections, the appearance of a jagged coastline (pl. xxxv, fig. 3; pl. xxxvi, figs. 2-3). primary branches connect with the central cavity through a short and narrow tubule (pl. xxxvii, fig. 4); the more swollen the branch and the nearer to the central cavity, the shorter the tubule, becoming, in some cases, only a larger or smaller pore at the base of the branch and thus enabling the direct communication. secondary branches without pronounced basal constrictions grow out either from the distal surface and the above mentioned protrusions (pl. xxxv, fig. 3; pl. xxxvi, figs. 2-3) or, very often, sidewise, from the lateral surface of the primary branch (pl. xxxv, fig. 2; pl. xxxvi, fig. 7). the number of the secondaries cannot be established with certainty, but it seems to be variable and to depend on the distal surface area. the secondaries are acrophorous, i.e., have the same diameter all along their length, and they extend to near the outer surface, where they branch off into short tertiaries. the fact that a secondary branch often emerges sidewise from the primaries, sometimes from near the base or even from the proximal rim (pl. xxxvi, fig. 7), may produce the illusion, in some sections, of sterile primary branches (pl. xxxvi, fig. 5; pl. xxxvii, figs. 2-3), arranged as in c h i n i a n e l l a in the sense of g r a n i e r et al. (1994) interpretation. specimens which, in addition to large primaries as described above, also have, in the lower part of the thallus, preserved relict branches of the p. barrabei type (pl. xxxviii, fig. 8) are exceptionally rare, which testifies to their direct phylogenetic connection. tertiary branches are very rarely visible, due to erosion of the outer surface, but nevertheless it is evident that their diameter is larger than that of the secondary branches, which suggests that the tertiaries are of the phloiophorous type. individual cysts, or groups of cysts, observed in the cavities of the primary branches, indicate the cladospority of the species. similarities and differences: from the specific characteristics of the primary branches, p. benceki i s distinguished from other species of the genus, though it shows unequivocal phylogenetic relationships with some. visually, however, it is more similar to the species of the genus c h i n i a n e l l a , particularly to ch. ma c r o p o r a (di stefano & senowbari-daryan) , due to the large pores of the primaries, which are, however, much more irregular in p. benceki. besides, the intusannulation in p. benceki is weaker than in ch. macropora . the egg-shaped thallus, as stated to exist in ch. macropora , clearly differs from the cylindrical or slightly club-shaped thallus in p. benceki, which shows, moreover, clear signs of intusannulation and, in some specimens, annulation. these features are not mentioned in any c h i n i a n e l l a species, all of which are characterised throughout by large pores. the essential difference, however, between ch. carpatica (b ys t r i c ký), ch. crossi (o t t), ch. zankli o t t, c h . m a c r o p o r a (di stefano & senowbari-darya n), ch. micropora (di stefano & senowbarid a r y a n), and c h . e l l e n b e r g e r i b e r n e t r o l l a nde & lemoine on the one hand and p. benceki o n the other hand, is the existence of alternating whorls of fertile and sterile primary branches in all c h i n i a n e l l a species, whereas in p. benceki only fertile primaries are present. the illusion of sterile primaries in p. benceki in parts of some sections (pl. xxxv, fig. 4; pl. xxxvi, fig. 5; pl. xxxvii, figs. 2-3) is due, as previously stated, to the mutual crossing of those secondary branches that grow out sidewise from the primaries. the fact is, that no sterile branches could be unequivocally ascertained in p. benceki, and moreover, they could not be accommodated amongst the densely packed primary maximum observed length of thallus l 12.0 outer thallus diameter d 2.06 3.74 inner thallus diameter d 0.40 0.72 relation d/d 0.128 0.281 distance between whorls h 0.54 0.85/2 diameter of primaries p 0.48 0.80 length of primaries l 0.44 0.68 number of primaries in a whorl w 9 12 diameter of secondary p’ 0.05 0.11 length of secondary l’ 0.24 0.58 number of secondary on a primary w’ do 8 diameter of tertiaries p’’ 0.04 0.11 length of tertiaries l’’ 0.15 0.34 number of tertiaries on a secondary w’’ 3 4 table 13 main biometrical parameters of p a l a eodasycladus benceki n. sp. (all dimensions in mm). 166 geologia croatica 54/2 branches, both within a whorl and in the neighbouring whorls (pl. xxxv, figs. 1, 5-6; pl. xxxvi, figs. 2, 4). stratigraphic position: p. benceki is one of the species contained in the algal assemblage of sample vt-26 of early liassic age. palaeodasycladus asteriscus n. sp . pls. xxxix-xl origin of the name: a s t e r i s c u s (lat.) = little star, diminutive of a s t e r ; in deeper tangential sections, cutting the distal part of the primary branch where the secondary branches emerge, the pattern is similar to the typographical asterisk mark. t y p e l o c a l i t y : mt. velebit, east of jadiëevac hill (1,274 m), on the forest road crossing the central ridge of mt. velebit between baπke oπtarije and buæimsko bilo and merging into the longitudinal road jadovno kalanjeva ruja (fig. 8); co-ordinates: 15°1 2’2”e , 44°33’20”n. type stratum: grey, well-bedded limestone, often late diagenetically dolomitized; alternation of peloidskeletal wackestone and ooid, sometimes ooid-skeletal grainstone. the algal-bearing sample has been determined as ooid-peloidal-skeletal grainstone. skeletal particles are predominantly represented by gastropod and algal fragments. the stratigraphic position of the holotype-bearing sample corresponds to the hettangian lower sinemurian. holotype: oblique section figured in pl. xxxix, fig. 2, thin-section jd-6b/5. holotype material, as well as the illustrated paratype materials, are stored in the collection of the institute of geology in zagreb. the available material includes about 30 variously oriented sections. d i a g n o s i s : the cylindrical skeleton with an integral inner cavity is characterised by regularly but distantly spaced whorls of primary branches. the main speciesspecific characteristic refers to the secondary branches, which in some specimens are directed upwards or downwards, almost parallel to the central cavity. this results in an asterisk-like section of the upper part of the primary branches, from where the secondary branches grow out. tertiary branches are short and arranged in bundles. description: a comparatively large calcareous skeleton of a regularly cylindrical thallus with a clearly delineated central cavity (pl. xxxix, figs. 2-3). the outer surface appears to be originally even and smooth, covered by pores of the tertiary branches; it is often subsequently eroded by shallow indentations (pl. xxxix, figs. 1-3; pl. xl, figs. 1-4). the central cavity occupies 20-35 % of the outer thallus diameter (table 14). the branches are arranged in regular, rather widely spaced whorls, which is also a species-specific characteristic (pl. xxxix, figs. 1-6). primary branches are elongated, sometimes more or less regularly phloiophorous, more often appearing to be deformed or irregularly shaped (pl. xxxix, figs 2-3, 5). they are situated either perpendicularly to the growth axis, or, more frequently, directed upwards (pl. xxxix, figs. 1, 5), or, more rarely, in the same specimen, they may even be inclined downwards (pl. xxxix, fig. 2). the most obvious species-specific characteristic is the direction of growth and the position of the secondary branches. they grow out from the distal end or from the sides of the top of a primary branch, and soon after emerging diverge radial into opposite directions. therefore sections cutting through this level do not show, except in very rare occasions (pl. xxxix, fig. 1 top), the otherwise characteristic grouping of pores of secondary branches, typical of the type-species and its varieties. this position of secondary branches at the level of their emergence results, in tangential sections, in a large pore of the primary branch and radially arranged, elongated pores of the secondary (pl. xxxix, fig. 3; pl. xl, fig. 1 top). in oblique and longitudinal sections, those secondary branches that are directed almost parallel to the longitudinal growth axis (pl. xxxix, figs. 2-3) may be abraded to the extent that they form an inner annular cavity that seemingly separates the calcareous skeleton fig. 8 map of the jadiëevac peak area in the central mt. velebit, type locality of the samples jd-6b and jd-13. scale 1:50,000. 167sokaë: lower and middle liassic calcareous algae (dasycladales)... into an inner and an outer part (pl. xxxix, fig. 5). a similar pattern may appear in transverse sections, in cases where the secondaries of neighbouring primaries of the same whorl converge towards each other (pl. xl, figs. 6-8). those secondaries that are, due to their almost longitudinal position, confined to the interior of the calcareous envelope, lack the tertiaries, which are otherwise normally developed on those secondaries that are directed outwards (pl. xxxix, figs. 1-2). the secondary branches are comparatively short, of small diameter, some with slightly widened distal ends. because of the position of part of the secondary just described, the number of their pores in shallow tangential sections appears to be small (pl. xxxix, figs. 2-4). tertiary branches, in turn, are barely visible (if at all), due to the eroded outer surface. those few that can be discerned, suggest that they are short, thin, and arranged in bundles that reach the outer surface. the species is supposed to be cladosporous. similarities and differences: from its general morphological characteristics, p. asteriscus n. sp. fits into the genus palaeodasycladus , where it differs from other described species. the main characters distinguishing it from other p a l a e o d a s y c l a d u s species are the widely spaced whorls and secondary branches of the same primary branch diverging into opposite directions. these differences are even more pronounced in those specimens of p. asteriscus , in which there is a secondarily developed annular cavity formed by merging of the opposingly directed secondary branches. this results, among other things, in a different arrangement of the pores of the secondary branches, in the appearance of a star-shaped cavity as opposed to bundles of pores in other species, and in a smaller number of pores per unit of the outer surface in p. asteriscus . stratigraphic position: p. asteriscus has been discovered in the lower part of the lower liassic part of the stratigraphic column, about 20 m above the dolomite/limestone boundary and about 150 m below the first occurrence of the foraminiferal genera o r b i t o p s e l l a and l i t u o s e p t a. in the fossil assemblage of this part of the lower liassic, palaeodasycladus mediterra n e u s and p. dolomiticus are the dominant species. the position of the sample with p. asteriscus can be therefore defined as the lower liassic in age, and most likely the lower part of the lower liassic, corresponding to the hettangian. genus eodasycladus cros & lemoine, 1966 ex granier & deloffre, 1993 selected synonymy: 1966 eodasycladus n. gen. cros & lemoine, p. 161-162, fig. 8-2. 1978 eodasycladus cros & lemoine, 1966 bassoullet et al., p. 97. 1993 eodasycladus cros & lemoine, 1966 granier & deloffre, p. 30, 45. 1993 e o d a s y c l a d u s cros & lemoine, 1966 ex granier & deloffre, 1993 barattolo et al., p. 4-6. the genus eodasycladus has been established by cros & lemoine (1966) from a lower liassic algal assemblage, where they observed specimens similar to, but different from, palaeodasycladus barrabei . these specimens were characterised by third-order ramifications, constrictions and swellings in the tertiary branchmaximum observed length of thallus l 12.5 outer thallus diameter d 1.60 2.70 inner thallus diameter d 0.35 0.67 relation d/d 0.180 0.350 distance between whorls h 0.39 0.72 diameter of primaries p 0.12 0.20 length of primaries l 0.15 0.35 number of primaries in a whorl w diameter of secondary p’ 0.09 0.10 length of secondary l’ 0.15 0.44 number of secondary on a primary w’ 4 6 diameter of tertiaries p’’ 0.06 0.20 length of tertiaries l’’ 0.12 0.20 number of tertiaries on a secondary w’’ 3 4 angle of inclination of branches α 35° table 14 main biometrical parameters of p a l a eodasycladus asteriscus n. sp. (all dimensions in mm). 168 geologia croatica 54/2 es, and, most importantly, a bubble-shaped swelling of one of the secondary branches, which did not give rise to tertiary branches. such an excessively swollen, bubble-shaped, secondary branch functioning as a choristosporous reproductive organ, was developed irregularly, but always in upper parts of the plant and in various positions with regard to other secondaries of the same whorl (cros & lemoine, 1966, fig. 9). this was the main characteristic of the new genus and also the main difference from p a l a e o d a s y c l a d u s . in the latter the development of fertile secondary branches is not known to exist. eodasycladus ogilviae cros & lemoine, 1966 pl. xli selected synonymy: 1966 eodasycladus ogilviae n. sp. cros & lemoine, p. 162-163, fig. 9, pl. 1, figs. 3-4, 6-7, non fig. 5. 1978 eodasycladus ogilviae cros & lemoine bassoullet et al., p. 97-100, pl. 10, figs. 1-3. 1994 eodasycladus ogilviae cros & lemoine, 1966 ex granier & deloffre, 1993 barattolo et al., p. 4-7. as previously mentioned, only specimens that unequivocally show one of the secondary branches within a bundle transformed into a strongly swollen bubbleshaped body are assigned here to this species. such forms correspond to the “type iii” of e o d a s y c l a d u s o g i l v i a e by cros & lemoine (1966), for which the presence of “sporangia” was said to be characteristic. the species has a cylindrical or, possibly, slightly clubshaped thallus, with a slightly undulated or shallowly annulated outer surface (pl. xli, figs. 1-2, 6, 8). more rarely, the outer surface is abraded and even. in some specimens, the skeleton seems to be composed of a row of shallow, barrel-shaped segments (pl. xli, fig. 1). the central cavity may exhibit even or wavy surface, as a result of more or less developed intusannulation (pl. xli, figs. 2, 6). all these characteristics represent the heritage of p. barrabei . the direct descendance of e. ogilviae from p. bar r a b e i is evidenced by the whorls of primary branches that are spaced far apart one from another and connect to the central cavity through a pore situated at, or immediately below, the inward projecting annular bulge of the inner wall. the primary branches are perpendicular to the thallus or are directed slightly upwards. they are small, slightly club-, bubble-, or stump-shaped. each primary branch gives rise to 5-8 tubular (acrophorous), thin, and always more or less curved and mutually diverging secondary branches (pl. xli, fig. 4), which, in turn, each give rise to 3-4 short tertiaries (table 15). the essential characteristic which served to establish the genus refers to a strongly swollen secondary branch within a bundle (pl. xli, figs. 1-2, 6, 9). this bubble-shaped body, which is considered to function as a sporangium (cros & lemoine, 1966) or a choristosporous reproductive organ (barattolo et al. 1994), is, however, irregular; it occurs in some branches within a whorl, in some whorls, or, more often, in the younger parts of the plant. the sporangial “bubble” may be situated in the middle of a bundle or at any side (pl. xli, figs. 1-2, 6). this feature gives the species a choristosporous character. similarities and differences: e . o g i l v i a e and p . b a r r a b e i show a clear phylogenetic relationship, with maximum observed length of thallus l 6,86 outer thallus diameter d 1,94 2,56 inner thallus diameter d 0,48 0,54 relation d/d 0,190 0,247 distance between whorls h 0,40 0,72 diameter of primaries p 0,07 0,20 length of primaries l 0,15 0,30 number of primaries in a whorl w ? diameter of secondary p’ 0,06 0,10 length of secondary l’ 0,30 0,64 number of secondary on a primary w’ 5 8 diameter of tertiaries p’’ 0,09 0,12 length of tertiaries l’’ 0,20 0,24 number of tertiaries on a secondary w’’ 3 4 table 15 main biometrical parameters of e o dasycladus ogilviae cros & lemoine (all dimensions in mm). 169sokaë: lower and middle liassic calcareous algae (dasycladales)... numerous almost identical, or very similar, features. as early as the original description, cros & lemoine (1966) emphasised the existence of transitional forms from the type ii (with characteristics of p. barrabei ) to type iii (eodasycladus ogilviae), in which the beginnings of swelling of individual secondary branches may be seen. the only obvious difference between the two species is the presence of swollen, bubble-shaped bodies in e. ogilviae, probably functioning as choristosporous reproductive organs. this was deemed to be a sufficiently significant, qualitative difference for establishing the new genus. irrespective of acceptance, for the time being, of eodasycladus as a valid genus, the question of whether a probably choristosporous reproduction, besides numerous identical features with the parent species, is sufficient for establishing the new genus, remains unanswered. when compared with the forms which are herein assigned a status of species (p. ala nensis and p. benceki) and which may be aligned into a phyletic lineage p. barrabei p. a l a n e n s i s p. benceki and with which e. ogilviae shares some visual similarity, e. ogilviae differs from all those species by irregularly developed “sporangia”. primary branches in p . alanensis are bowl-shaped or budding and in p. benceki they are irregularly nodular, in contrast to e . o g i l v i a e, in which only one among the secondary branches swells and acquires an irregularly bubble-like shape. statistically a dozen sections of this species, compared with several hundreds sections of other p a l a e o d a s y cladus species, all from samples from the same locality, does not suggest an infallible firm conclusion. a few specimens in a rich and diversified (on the species level) assemblage may equally indicate a possible specific adaptation of some individuals as well as the early appearance of a possibly new genus. stratigraphic position: in the original description, cros & lemoine (1966) mention this species from the friulian alps in a rich algal assemblage which they consider to be of a sinemurian s. str. lotharingian age. ott (1974) ascribes this species to the middle liassic. in mt. velebit, the material figured in pl. xli derives from the rich algal assemblage of sample vt-26. its stratigraphic position has been determined as lower liassic (hettangian sinemurian). genus selliporella sartoni & crescenti, 1962 emend. barattolo et al., 1988 selliporella ? problematica n. sp. pl. xlii, figs. 1-3 origin of the name: after problematic taxonomic position. t y p e l o c a l i t y : main ridge of mt. velebit, at the sv. r ok obrovac road, about 100 m in the direction of obrovac from the milestone at the mali alan pass (fig. 7); co-ordinates 44°17’24” n, 15°39’23” e. type stratum: grey, well-bedded, lower liassic ( h e t t a n g i an lower sinemurian) limestone; alternating skeletal-intraclastic grainstone and mudstone, with sporadically developed stromatolitic laminae. the strata were deposited in a shallow subtidal environment with temporary emergence into vadose zone. h o l o t y p e : tangential-oblique section, figured in pl. xlii, fig. 1, thin-section vt-26/400. the holotype, and other material containing the illustrated sections, is stored in the collection of the institute of geology, zagreb. d i a g n o s i s : thallus cylindrical, clearly annulated, with obliquely incised annular depressions, some of which may be as deeply cut as to reach the wall of the central cavity. calcareous annuli (rings) between consecutive annular incisions taper going outward but seem to widen again at the outer end. each calcareous ring bears one whorl of bipartite branches. primary branches are irregularly cylindrical, slightly swollen at the proximal ends, and sporadically with larger or smaller bagshaped excrescences on the lower side. secondary branches are longer than the primaries and distally widened. the species is cladosporous. d e s c r i p t i o n : the calcareous skeleton has a cylindrical shape with clearly developed annulation (pl. xlii, fig. 1). annular depressions are obliquely incised into the calcareous envelope, directed downwards, and, some of them, almost reach the wall of the central cavity (pl. xlii, fig. 1). calcareous segments which are inserted obliquely between the annular cavities, taper outwards but become wider at the very distal ends. in the available material, the widenings of the calcareous segments can barely be seen (e.g., pl. xlii, fig. 1), because they are heavily reduced due to the destruction of the outer parts of the skeleton. therefore, the calcareous skeleton, as a whole, gives, in oblique and longitudinal sections, a many-horned appearance. the inner cavity is delimited by a smooth and clearly defined calcareous wall, which occupies about 30% of the outer thallus diameter (table 16). each calcareous segment contains one whorl of branches, which are clearly divided into primary and secondary branches, whereas the third-order branches remain questionable. in pl. xlii, fig. 1 (lower left) a group of three pores may be seen, as well as a larger pore lower down, with a tiny pore in the immediate vicinity which may indicate a tertiary branch. also, the possible existence of the tertiary branches is suggested by widened pores, resulting from the widened distal ends of the secondary branches, which may indicate that the development of tertiary branches has directly influenced the more swollen distal ends of the secondary branches. primary branches are comparatively 170 geologia croatica 54/2 regular, of cylindrical shape, as may be seen in the upper part of the holotype (pl. xlii, fig. 1), or else more or less irregularly shaped as may be seen in the lower right part of the same section, near the central cavity. there, as well as on the branches of neighbouring segments, one can see the beginning of the development of an irregular swelling, projecting from the lower surface of the proximal part of a branch. the secondary branches are more or less irregularly shaped, differing from segment to segment; they emerge in a more or less dichotomous manner from the distal ends of the primary branches, and are ?2-3 in number (table 16). in spite of their acrophorous appearance in the figured sections, or even suggesting a slight narrowing toward the distal end, which may be an artifact of the section, they probably still widen distally and give rise to the tertiary branches, as has been mentioned above. in several pores of the primary branches indications of cysts may be found, which would support the cladospority of this species. similarities and differences: the distinctly segmented thallus (calcareous skeleton) and from the shape of some branches this species appears similar to s e l l i porella donzellii sartoni & crescenti. in addition to clearly developed segmentation (annulation), the similarity also refers to a comparatively small number of pores per unit of the outer surface of calcareous segments, as seen in shallow tangential (cortical) sections, and to the shape of the pores of some primary branches in deep tangential sections, near the central cavity (pl. xlii, fig. 1). further similarity with selliporella don z e l l i i concerns the beginning of the development of a small, irregular excrescence projecting down from the lower surface of some primary branches, though a similar feature may also be developed in some specimens of palaeodasycladus mediterraneus var. mediterraneus . a clear difference between this species and s e l l i p o r e l l a d o n z e l l i i is, on the one hand, the much more strongly and regularly developed bag-shaped excrescence in the latter, hanging down from the proximal part of the primary branches (barattolo et al., 1988, fig. 3); on the other hand, the new species has retained several branches very similar to those in p. mediterraneus . the main difference to s. donzellii, and at the some time a further similarity with p. mediterraneus , would be the existence of third-order branches, which, however, cannot be unequivocally ascertained (though the indications pointing to their existence in s e l l i p o r e l l a? p r o b l e m a t i c a are rather strong). all these characters clearly show the connection of s .? p r o b l e m a t i c a with p. medi t e r r a n e u s on the one hand and its similarity with s . d o n z e l l i i on the other, thus giving s .? p r o b l e m a t i c a a n intermediate position. s .? p r o b l e m a t i c a most likely evolved from p. mediterraneus and probably gave rise to s. donzellii. this alga is very rare; it is represented by only a few sections in numerous slices and among numerous sections of other species; its scarcity makes deeper analysis very difficult. however, this scarcity alone suggests that it is a new form. thus the small number of specimens is not surprising, because it is a well known fact that new forms arise as a result of separation or, possibly, deviation of individual specimens, whereas the bulk of the ancestral forms will either keep on evolving in their own lineage or soon become extinct. stratigraphic position: this alga occurs in the rich algal assemblage of sample vt-26, belonging to the lower part of the lower liassic. this is supported by the position of the assemblage in the stratigraphic column (fig. 2) maximum observed length of thallus l 11.3 outer thallus diameter d 2.06 2.40 inner thallus diameter d 0.48 0.68 relation d/d 0.232 0.287 distance between whorls h 0.60 0.96 diameter of primaries p 0.24 0.34 length of primaries l 0.40 0.48 number of primaries in a whorl w 10 12 diameter of secondary p’ 0.15 length of secondary l’ 0.82 0.86 number of secondary on a primary w’ ?2 3 diameter of tertiaries p’’ ? length of tertiaries l’’ ? number of tertiaries on a secondary w’’ ? angle of inclination of branches α 25° 40° table 16 main biometrical parameters of s e l l i p o r e l l a? problematica n. sp. (all dimensions in mm). remark: because the species is very rare, the above dimensions have been measured in only three specimens. 171sokaë: lower and middle liassic calcareous algae (dasycladales)... genus humiella soka» & veli∆, 1981 emend. masse et al., 1984 humiella japodica n. sp. pl. xlii, figs. 4-8 origin of name: the name recalls the ancient illyric tribe of iapodes, who had their settlements in the northern foothill of mt. velebit and also frequently settled on the mountain itself. type locality: mt. velebit, east of trigonometric point jadiëevac (1,274 m), on a forest road crossing the main ridge of mt. velebit between baπke oπtarije and buæinsko bilo and joining the longitudinal road jadovno kalanjeva ruja (fig. 8); co-ordinates: 15°12’2 7” e ; 44°33’18” n. type strata: dark grey, well-bedded limestone, often turned into late diagenetic dolomite, represented by alternation of peloidal-skeletal wackestones and oolite, sporadically ooid-skeletal grainstone (fig. 2). mudstone occur as rare lenses or thin intercalations. the algalbearing sample is an ooid-peloidal-skeletal grainstone. skeletal particles are predominantly represented by fragments of gastropods and calcareous algae. the stratigraphic position of the algal-bearing sample, between the upper triassic dolomite and the first occurrence of middle liassic foraminiferal assemblage, is suggested to be hettangian in age. h o l o t y p e : the oblique-transverse section figured in pl. xlii, fig. 6, slide jd-13/14. this slide, as well as other slides containing the figured paratype material, is stored in the collection of the institute of geology, zagreb. because of the scarcity of the available material, the following description is based on only 7 sections. diagnosis: the calcareous skeleton consists of a central tube which bears individualised branches, swollen proximally and tapering distally, of a generally piriform appearance of the whole alga. branches touch mutually where thickest, but toward the exterior they become thin, pointed, and well separated, producing the appearance of a spinose club. in neighbouring whorls, branches are arranged in alternating positions. calcareous envelopes of individual branches are perforated by tiny tubules. description: the calcareous skeleton of this alga consists of a central cylindrical tube, which bears dense, mutually alternating, piriform-shaped branches which taper and become pointed outwards. this gives this alga the appearance of a spinose cylinder, or even a cylindrical spinose club. the central cavity looks regular and clearly delimited, occupying about 25-35% of the total thallus diameter (table 17). the entire structure results from the existence of undivided piriform branches with tapering ends pointing outwards (pl. xlii, fig. 4). branches are comparatively large, with regard to general dimensions, with rounded bases and swollen in their lower proximal parts. at this level the branches appear tightly packed and in mutual contact (pl. xlii, figs. 4-5). further outwards, the branches gradually, but apparently not uniformly, taper to a more or less pointed termination (pl. xlii, fig. 4). in the outer region of the thallus (in the first half of their length), the envelopes of the branches mutually touch no longer, and are fully individualised, producing smaller pores and independent circular sections of their calcareous envelopes in tangential sections. the calcareous envelopes of individual branches are perforated by numerous tiny and short tubules directed perpendicularly to the surface (pl. xlii, fig. 5). as a result of recrystallisation and a partly destroyed central wall, these tubules could not be seen with certainty in all sections. the species is probably cladosporous. similarities and differences: its skeletal structure, individualised branches, and overall appearance of the thallus, and particularly the existence of tiny tubules perforating the calcareous envelopes of the branches, suggest that humiella japodica n. sp. unquestionably belongs to the genus h u m i e l l a. the existence of such perforations in the envelopes of branches and in the wall of central cavity has been established by m a s s e et al. (1984) as an essential feature of the genus h u m i e l l a , and is illustrated by soka» (1987) in a more complete description of the type-species. h. japodica clearly differs from all other, though not numerous species ascribed to this genus and, moreover, has the outer thallus diameter d 0.62 1.70 inner thallus diameter d 0.20 0.48 relation d/d 0.241 0.385 distance between whorls h 0.15 0.24 diameter of primaries p 0.17 0.35 length of primaries l 0.28 0.45 number of primaries in a whorl w 6 7 table 17 main biometrical parameters of h u m i ella japodica n. sp. (all dimensions in mm). 172 geologia croatica 54/2 lowest (= oldest) stratigraphic position. it differs from h. teutae soka» & veli∆ (the type-species) by being generally much smaller and by having swellings and taperings of the branches in reverse order. this latter feature is valid also in comparison with h. sar d i n i e n s i s (ott & f l a v i a n i), h. dalmatarum ( s oka» & veli∆) and h. catenaeformis (r a d o i » i ∆, 1967) m a s s e et al. 1984. moreover, those species have more strongly developed perforations of the central stem and in the envelopes of the branches. as regards the inadequately known and problematic humi e l l a? p u p n a t e n s i s soka», the differences are also clear, as h. pupnatensis (= similiclypeina pupnatensis (soka») bucur, 1993) is said to have 2-3 whorls of smaller branches alternating with whorls of longer, horn-like, more or less autonomous branches. and finally, in spite of the fact that the stratigraphic position has no significance for determination and differentiation of species, it nevertheless may be a useful indication in an early stage of determination. stratigraphic position: humiella japodica n. sp. has been discovered east of jadiëevac, in the central part of mt. velebit, in lower liassic deposits containing numerous p . m e d i t e r r a n e u s var. m e d i t e r r a n e u s , p. dolo m i t i c u s and p. asteriscus . the position of the sample with h. japodica in the stratigraphic column is about 40 m above the boundary with the upper triassic dolomite and about 130 m below the first occurrence of the foraminiferal assemblage marking the beginning of the middle liassic. the age corresponds to the hettangian. acknowledgements this presentation is the result of the described material having collected during many years of fieldwork and with the participation of several colleagues, to whom i express my sincerest thanks. these are, first of all, ivo veli∆ and josip ti©ljar, to whom i wish to express my thanks, not only for participation in fieldwork but also for determination and biostratigraphic interpretation of foraminifera, and sedimentary-petrographic analyses and environmental interpretations, respectively. i thank tonêi grgasovi∆ for his help in the technical preparation of the text, and igor vlahovi∆ as the technical editor of the journal. i am grateful to the reviewers, ivan gu©i∆ and marc. a. conrad for their many useful suggestions and corrections of mistakes. however, for the sake of respecting the authenticity of opinion of one reviewer, it should be emphasised that marc. a. conrad does not agree with my synonymy of f a n e s e l l a with p a l a e o d a s y c l a d u s and l i noporella buseri r a d o i » i ∆ with p. mediterraneus var. g r a c i l i s (cros & lemoine). m.a. conrad also considers p. asteriscus synonymous with l i n o p o rella buseri . however, on the basis of arguments presented in favour of my interpretations in the above text, i could not accept these well-intentioned suggestions. 3. references barattolo, f. (1978): su di una nuova dasicladacea (alghe verdi) nel paleocene dell’appennino meridionale.bollettino della società dei naturalisti in napoli, 87, 83157. barattolo, f., bigozzi, n. & potenza, a. (1996): dasycladaleans and depositional environments of the upper triassic-liassic carbonate platform of the gran sasso (central apennines, italy).facies, 35, 163-208. barattolo, f., de castro, p. & parente, m. (1994): some remarks on the genera palaeodasycladus (pia, 1920) pia, 1927 and eodasycladus cros & lemoine, 1966 ex granier & deloffre, 1993 (green algae, dasycladales).beiträge zur paläeontologie österreich, 19, 111. barattolo, f., de castro, p. & radoi»i∆, r. (1988): the genus selliporella sartori & crescenti 1963 (chlorophyta, dasycladales) and its type-species.memoire della societa geologica italiana, 41, 593-604. bassoullet, j.p. (1997): algues dasycladales distribution des principales espèces.in: cariou, e. & hantzpergue, p. (coord.): biostratigraphie du jurassique ouest-européen et méditerranéen: zonations paralléles et distribution et microfossiles. bulletin des centres recherches exploration-production elf-aquitaine, memoirs, 17, 339-341. bassoullet, j.p., bernier, p., deloffre, r., genot, p., jaffrezo, m., poignat, a.f. & segonzac, g. (1977): classification criteria of fossil dasycladales.in: flügel, e. (ed.): fossil algae. springer-verlag, 154-166, berlin. bassoullet, j.p., bernier, p., conrad, m.a., deloffre, r. & jaffrezo, m. (1978): les algues dasycladacées du jurassique et du crétacé.geobios, mém. spec., 2, 1-330. berger, s. & kaever, m.j. (1992): dasycladales. an illustrated monograph of a fascinating algal order.thieme, stuttgart, 247 p. bouroullec, j. & deloffre, r. (1970): les algues du jurassique aquitain.bull. centre rech. pan., s.n.p.a., 4/1, 79-127, pau. bucur, i.i. (1993): some new or poorly know calcareous algae (dasycladales, gymnocodiaceau) in the lower cretaceous deposits from resita-moldova nova zone (southern carpathians, romania).revista española de micropaleontologia, 25/1, 93-125. b y s t r i c ký, j. (1967): die obertriadischen dasycladazeen der westkarpaten.geologický sbornik geologica carpathica, xviii/2, 285-309. cros, p. & lemoine, m. (1966): dasycladacées nouvelles on peu connues du lias inférieur des dolomites et de quelques autres régions mediterranéennes (1r e p a r t i e ) . revue de micropaléontologie, 9/3, 156-168. cros, p. & lemoine, m. (1967): dasycladacées nouvelles on peu connues du lias inférieur des dolomites et de quelques autres régions mediterranéennes (2e p a r t i e ) . revue de micropaléontologie, 9/4, 246-257. 173sokaë: lower and middle liassic calcareous algae (dasycladales)... de castro, p. (1997): introduzione allo studio in sezione sottile delle dasicladali fossili (an approach to thin-section study of fossil dasycladales).quaderni dell’accademia pontaniana, 22, 261 p., napoli. deloffre, r. (1972): palaeodasycladus elongatulus praturlon, 1966 dans le lias inférieur d’ andalousie (espague).bull. centre rech. pau, s.n.p.a., 6/1, 107-119. deloffre, r. & laadila, m. (1990): un niveau exceptionnel à palaeodasycladus mediterraneus dans le lotharingien du moyen-atlas (maroc) emendation du genera et de’l espece-type.revue de paléobiologie, 9/2, 309320. di stefano, p. & senowbari-daryan, b. (1985): upper triassic dasycladales (green algae) from the palermo mountains (sicily, italy).geologica romana, 24, 189-218, roma. dragastan, o., gielisch, h., richter, d.k., grewer, t., kaziur, t., kube, b. & radusch, c. (1994): jurassic algae of the perachora-peninsula: biostratigraphical and paleoecological implications.beiträge zur paläeontologie österreich, 19, 49-81. granier, b. & deloffre, r. (1993): inventaire critique des algues dasycladales fossiles. iio partie: les algues dasycladales du jurassique et du cretacé.revue de paléobiologie, 12/1, 19-65. granier, b., masse, j.-p. & berthon, p.-y. (1994): heteroporella lepina praturlon, 1967, revisited (folowed by taxonomic notes on the so-called “heteroporella” species).beiträge zur paläeontologie österreich, 19 (proceedings of the international symposium and field-meeting “alpine algae 93”), 129-141. hurka, h. (1967): variationsstatistische untersuchungen an anisischen dasycladaceen aus den pragser dolomiten in südtirol.neues jahrbuch für geologie und paläontologie, abhandlungen, 128/1, 41-100. kochansky-devidé, v. (1970): permski mikrofosili zahodnih karavank (permische mikrofossilien der westkarawanken).geologija, 13, 175-256, ljubljana. lebouché, m.c. & lemoine, m. (1963): dasycladacées nouvells du lias calcaire (lotharingien) du languedoc mediterranéen (st. chinian, boutenac).revue de micropaléontologie, 6/2, 89-101. masse, j.p., acquaviva, m. & luperto-sinni, e. (1984): humiella catanaeformis (radoiëiê), nov. comb. (dasycladale) de l’eocrétacé italo-dinarique.revue de micropaléontologie, 27/2, 139-143. mamet, b. & rudloff, b. (1972): algues carboniferes de la partie septentrionale de l’ amérique du nord.revue de micropaléontologie, 15/2, 75-114. nikler, l. & soka», b. (1968): biostratigraphy of the jurassic of velebit (croatia) (biostratigrafija jure velebita).geoloπki vjesnik, 21, 161-176. ott, e. (1967): dasycladaceen (kalkalgen) aus der nordalpinen obertrias.mitteilungen der bayerische staatssammlung für paläontologie und historische geologie, 7, 205226, münchen. ott, e. (1974): algae (dasycladaceae).in: zapfe, h. (ed.): catalogus fossilium austriae. eine systematisches verzeichuis aller auf österreichischen gebit festgestellten fossilien, heft xviib. österreichischen akademie der wissenschaften (springer-verlag), wien, 64 p. ott, e. & flaviani, a. (1983): eine neue kalkalgengattung (lagenoporella, dasycladales) aus dem oberjura von sardinien.neues jahrbuch für geologie und paläontologie, monatshefte, 1, 16-26. pia, j. (1912): neue studien über die triadischen siphoneae verticillatae.beiträge zur paläontologie und geologie österreich-ungarns und des orients, xxv, 25-81, wien und leipzig. pia, j. (1920): die siphoneae verticillatae von karbon bis zur kreide.abhandlungen der zoologisch-botanischen gesellschaft in wien, 11/2, 1-236, wien. pia, j. (1927): 1. abteilung: thallophyta.in: hirmer, m.: handbuch der paläobotanik. oldenbourg, bd. i, 31-136, münchen und berlin. praturlon, a. (1966): algal assemblages from lias to paleocene in southern latium-abruzzi: a review.bolletino della società geologica italiana, 85, 167-194. radoi»i∆, r. (1966): microfaciès du jurassique des dinarides externes de yugoslavie.geologija, 9, 5-377, ljubljana. radoi»i∆, r. (1975): linoporella buseri sp. nov. from the liassic of the julian alps (a preliminary report).bulletin scientifique, cons. acad. yougosl. (a), 20/9-10, 277-278, zagreb. sartoni, s. & crescenti, u. (1962): richerche biostratigrafiche nel mezozoico dell’ appennino meridionale.giornale di geologia, 29 (1960-1961), 162-302, 42 pls., bologna. soka», b. (1987): on some controversial dasyclad genera and species and their stratigraphic position in the lower cretaceous deposits of the dinarides.geoloπki vjesnik, 40, 9-38. soka», b. (1988): fanesella anae n. sp. a new calcareous alga (dasycladaceae) from the lower lias of velebit mountain (croatia).geoloπki vjesnik, 41, 9-14. soka», b. (1996): taxonomic review of some barremian and aptian calcareous algae (dasycladales) from the dinaric and adriatic karst regions of croatia.geologia croatica, 49/1, 1-79. soka», b. & nikler, l. (1966): two new species of the genus petrascula from the lower lias of the velebit mountain.bulletin scientifique, cons. acad. yougosl. (a), 11/1-2, 7-8, zagreb. soka», b. & nikler, l. (1967): teutloporella elongatula (praturlon, 1966) sokaë & nikler, calcareous alga from the middle liassic of velebit.geoloπki vjesnik, 20, 111116. soka», b. & nikler, l. (1969): o vrstama roda petrascula iz donjeg lijasa velebita (on the species of the genus petrascula from the lower liassic of velebit).acta geologica, 6 (prirodoslovna istraæivanja, 36), 103-112, zagreb. soka», b. & veli∆, i. (1978): redescription of the genus selliporella (calcareous algae: dasycladaceae).geoloπki vjesnik, 30/1, 225-242. 174 geologia croatica 54/2 soka», b. & veli∆, i. (1981): humiella teutae n. sp. (dasycladaceae) from the neocomian of southern herzegovina.geoloπki vjesnik, 33, 101-105. manuscript received march 19, 2001. revised manuscript accepted november 20, 2001. plate i 1-5 palaeodasycladus mediterraneus (pia, 1920) 1927 var. mediterraneus 1 longitudinal, somewhat oblique, section. the gradual increase of the thallus diameter and wall thickness upwards along the thallus produces a club-shaped thallus. short, slightly developed primary branches bear phloiophorous, seemingly articulated, secondary and tertiary branches. tg-9/5, x17. 2 oblique-tangential section. variously shaped primary branches of variable size on both left and right side of the section. long secondary branches slightly thicken distally. vt-26/252, x14. 3-4 oblique sections. large, cylindrical, primary branches bear bundles of 2-5 phloiophorous secondaries, which, in turn, give rise to short, also phloiophorous, tertiaries. 3: jd-13, x22; 4: jd-8/2, x22. 5 oblique-tangential section. slightly oblique (ca. 25°), cylindrical primary branches bear phloiophorous secondary branches which emerge without a visible basal constriction. from their distal end, tertiary branches with constricted bases emerge. in large pores of the primaries (3 lowermost rows) groups of cysts can be seen (see enlarged detail in pl. xiv, fig. 1). this section correlates with pia’s reconstruction (pia, 1920, fig. 22). jd-14/1, x14. sample localities and ages tg: mt. trnovski gozd (western slovenia), middle liassic. vt-26: mali alan pass, central mt. velebit, lower liassic. jd-14: jadiëevac, central mt. velebit, lower liassic. 175sokaë plate i 176 geologia croatica 54/2 plate ii 1-3 palaeodasycladus mediterraneus (pia, 1920) 1927 var. mediterraneus 1 tangential section. note the increase in diameter of the secondand third-order branches. tg-9/2, x14. 2 longitudinal-oblique section. note the secondand third-order branches with distally increasing diameter. tg-8, x14. 3 oblique tangential section. in the lower part of the thallus, cylindrical, obliquely situated, primary branches are preserved, which bear seemingly articulated secondary and tertiary branches. in this part of the thallus, the inner wall of the central cavity is preserved (small inner diameter). in the upper part of the thallus, the central cavity appears much wider, because of the destruction of the inner surface and primary branches, of which only the contour is still visible. the morphology in the lower part of the thallus agrees with the reconstruction by pia (1920, fig. 22). tg-9/3, x17. sample locality and age mt. trnovski gozd, western slovenia. middle liassic. 177sokaë plate ii 178 geologia croatica 54/2 plate iii 1-7 palaeodasycladus mediterraneus (pia, 1920) 1927 var. mediterraneus 1 oblique tangential section. cylindrical to club-shaped phloiophorous primary branches arranged in loosely spaced whorls. bundles of 4 secondary branches can be seen in the tangential part of the section. vt-26/204, x17. 2 longitudinal tangential section. short, kidney-shaped or irregular primary branches; some are slightly bent in proximal part. in the tangential part of the section (lower part of the figure) fissures can be seen, either as inceptions or relics of possible annulation. tg-9/10, x22. 3 oblique section. specimen with destroyed primary and secondary branches, resulting in a very wide central cavity. such sections are ill-suited for determination. tg-9/18, x14. 4 oblique section. cylindrically shaped primary branches bear clearly phloiophorous secondaries and tertiaries which seem articulated (an optical illusion). vt-26/118, x22. 5 tangential section with visibly undulated outer surface of the skeleton. vt-26/17, x17. 6 tangential section with irregularly spaced narrow fissures (possible inceptions or relics of annulation). tg-9, x22. 7 transverse, slightly oblique section. lower part of the thallus may have a smaller number of primary branches per whorl and lower degree of ramification. tg-9/20, x34. sample locality and ages vt-26: mali alan pass, central mt. velebit, lower liassic. tg-26: mt. trnovski gozd, western slovenia. middle liassic. 179sokaë plate iii 180 geologia croatica 54/2 plate iv 1-6 palaeodasycladus mediterraneus (pia, 1920) 1927 var. mediterraneus 1 oblique longitudinal section. note the clear increase in diameter of the primary branches from bottom to top of thallus, resulting in the ever more reduced thickness of the calcareous partitions between the whorls and in the destruction in the region of primary branches. this is contrary to annulation being a primary feature (see the upper part of the thallus). vt-26/14, x22. 2 longitudinal section, showing the increase of the outer thallus diameter (club-shaped thallus) and of the primary branch diameter from bottom to top of the thallus. destroyed primary, and partly also secondary, branches in the top part of thallus do not indicate the existence of intusannulation or insufficient calcification of the primaries. vt-26/264, x17. 3 longitudinal-oblique section with preserved inner wall (wall of the central cavity) and partly, and to a different extent, the destroyed region of the primary branches, producing a visual impression of intusannulation. tg-9/27, x22. 4 oblique section with preserved wall of the central cavity, partly preserved proximal parts of partitions between the primary branches, and destroyed region of the primary and, partly, secondary branches. primary branches are still partly visible. this section contradicts the existence of intusannulation and insufficient calcification. vt-26/40, x14. 5 longitudinal-tangential section with preserved partitions between neighbouring whorls and erased walls of the central cavity. this feature has been incorrectly interpreted as intusannulation. vt-26/39, x22. 6 longitudinal section. the right side shows the preserved wall of the central cavity and the entire region of primary and secondary branches, which is on the left side partly to completely destroyed. this section also contradicts the existence of intusannulation. secondary and tertiary branches are visible, with sporadic indication of the existence of the fourth-order branches. vt-26/299, x17. sample localities and ages vt-26: mali alan pass, central mt. velebit, lower liassic. tg: mt. trnovski gozd, western slovenia, middle liassic. 181sokaë plate iv 182 geologia croatica 54/2 plate v 1-5 palaeodasycladus mediterraneus (pia, 1920) 1927 var. mediterraneus 1 oblique tangential section of a specimen with strongly irregular primary and secondary branches. in the basal part, bundles of 4 secondary branches may be seen. this is a unique specimen amongst hundreds of more regular ones. vt-26/43, x22. 2 longitudinal-oblique section of a specimen with steeply inclined primary branches the diameter of which decreases from the bottom to the top of the thallus. primary branches taper distally and give raise to long, acrophorous to slightly phloiophorous, secondary branches. vt-26/40, x17. 3 longitudinal-oblique section with cylindrical and conical primary branches, which give rise to long, slightly phloiophorous, secondary branches, which, in turn, bear short, phloiophorous tertiaries. vt-26/384, x17. 4 longitudinal-oblique section. note the increase of diameter and change in shape of primary branches from the bottom to the top of the thallus. in the basal part, primary branches are preserved. with their increasing diameter the envelopes of branches between the neighbouring whorls are destroyed whereas the wall of the central cavity is still preserved. this section denigrates the existence of intusannulation or insufficient calcification of the region of primary branches. vt-26/362, x17. 5 tangential section. pores of primary branches partly arranged in vertical rows, located one above the other, and partly approaching the alternating position. sporadically, in the pores of primary branches, individual cysts may be seen. jd-6b/5, x17. sample localities and ages vt-26: mali alan pass, central mt. velebit, lower liassic. jd-6b: jadiëevac, central mt. velebit, lower liassic. 183sokaë plate v 184 geologia croatica 54/2 plate vi 1-6 palaeodasycladus mediterraneus (pia, 1920) 1927 var. mediterraneus 1 longitudinal sections with cylindrical and kidney-shaped primary branches bearing long phloiophorous secondaries and short phloiophorous tertiaries. vt-26/27, x34. 2, 6 oblique sections with elongated and comparatively thin primary branches, giving rise to phloiophorous secondary, constricted at the base. secondary branches are grouped into bundles. 2: tg-9/12, x34; 6: vt26/54a, x34. 3 longitudinal section with cylindrical primary branches, some are curved at the base. vt-26/142, x22. 4 longitudinal section with irregular, often steeply inclined, primary branches, with broad bases opening into the central cavity. the wall of the central cavity is probably partly destroyed. short secondary branches bear “articulated”, phloiophorous, tertiaries. tg-9/5, x34. 5 longitudinal-oblique section of a specimen with heart-shaped and irregular short primary branches giving rise to well-developed secondary branches which, in turn, bear articulated, phloiophorous, tertiary branches. central cavity well delineated and straight. tg-9/19, x34. 7-8 palaeodasycladus mediterraneus var. illyricus (soka» & nikler, 1966) n. comb. 7-8 oblique sections with swollen-nodular primary branches, bearing longer, phloiophorous secondary branches, which, in turn, bear short, phloiophorous, tertiary branches. 7: vt-26/27, x34; 8: jd-4b, x17. sample localities and ages vt-26: mali alan pass, central mt. velebit, lower liassic. jd-4: jadiëevac, central mt. velebit. lower liassic. tg: mt. trnovski gozd, western slovenia, middle liassic. 185sokaë plate vi 186 geologia croatica 54/2 plate vii 1-2, 4 palaeodasycladus mediterraneus var. heraki (soka» & nikler, 1966) n. comb. 1 oblique section. rectangular primary branches bear bundles of secondary branches, constricted at the base. in the cavities of the primary branches, individual preserved cysts can be seen. vt-26/118, x34. 2 longitudinal section. rectangular primary branches of various size; comparatively thick, roughly shaped secondaries bear very short tertiaries. vt-26/428, x34. 4 oblique section with a comparatively well-preserved central cavity and individual cysts in the pores of the primary branches. vt-26/428, x34. 3, 5-9 palaeodasycladus mediterraneus (pia, 1920) 1927 var. mediterraneus 3 oblique section. note club-shaped primary branches bearing equally large secondary branches. jd-17a, x22. 5 longitudinal-oblique section of a specimen with preserved central cavity and elliptical-cylindrical primary branches and phloiophorous to acrophorous secondaries, constricted at the base. vt-26/400, x34. 6-8 longitudinal sections. specimens with cylindrical and kidney-shaped primary branches, more or less bent in the proximal part. long, tubular secondary branches of constant diameter bear short tertiaries. 6: vt-26/144, x22; 7: vt-26/47, x34; 8: tg-9/1, x34. 9 oblique section. note clearly club-shaped primary branches bearing bundles of comparatively short secondaries. the zone of distal branches is probably abraded. vt-26/454, x34. sample localities and ages vt-26: mali alan pass, central mt. velebit, lower liassic. jd-17a: jadiëevac, central mt. velebit, lower liassic. tg: mt. trnovski gozd, western slovenia, middle liassic. 187sokaë plate vii 188 geologia croatica 54/2 plate viii 1 palaeodasycladus anae (soka», 1988) n. comb. 1 longitudinal tangential section of a specimen with variously shaped primary branches, some of which branch off up to fourth-order branches. in the pores of some primary branches groups of cysts can be seen. vt-26/328, x14. 2-8 palaeodasycladus mediterraneus (pia, 1920) 1927 var. mediterraneus 2 longitudinal section. enlarged detail of pl. v, fig. 1, showing heavily deformed and extremely variable primary branches. vt-26/43, x34. 3, 5 fig. 3. is enlarged detail of fig. 5: oblique section of a micritized specimen with preserved central cavity and variously shaped primary branches, some of which show higher-order branching than others. vt-26/344; 3: x34; 5: x14. 4 oblique-tangential section of a specimen with completely preserved central cavity and clearly visible connecting pores between primary branches and the central cavity. primary branches have irregular and strongly widened distal terminations. vt-26/407, x22. 6 transverse, somewhat oblique section, of a specimen with small primaries, large secondary, and short and thin tertiaries. vt-26/114, x22. 7 part of a longitudinal section. conical and cylindrical primary branches bear clearly phloiophorous secondaries, some of which show partial constrictions. tertiary branches are short and have a small diameter. vt26/35, x34. 8 transverse-oblique section of a micritized specimen with thin, phloiophorous branches, clearly grouped into bundles at the secondand thirdorder branches. vt-26/221, x17. sample locality and age mali alan pass, central mt. velebit, lower liassic. 189sokaë plate viii 190 geologia croatica 54/2 plate ix 1, 8 palaeodasycladus mediterraneus (pia, 1920) 1927 var. mediterraneus 1 part of a longitudinal section of a specimen with irregular primary branches, elongated in the direction of growth. vt-26/426, x34. 8 part of a longitudinal section with elongated cylindrical and irregular primary branches (left and right side are not identical). secondary branches are either constricted at the base or finger-shaped, i.e. growing out like continuations of the primaries. vt-26/422, x34. 2-3, 5-7, 9-10 palaeodasycladus mediterraneus var. illyricus (soka» & nikler, 1966) n. comb. 2-3, 5-6, 9 oblique sections of specimens with bubble-shaped (elliptical) primaries (?); whorls spaced at regular intervals but rather far apart from each other. note secondary branches grouped into bundles in some specimens (figs. 5-6, 9). 2: vt-26/88, x22; 3: vt-26/297, x17; 5: vt-26/266, x17; 6:ob-9619/42, x22; 9: vt26/83, x17. 7, 10 transverse, somewhat oblique sections. bubble-shaped (elliptical) primary branches bear secondary branches characterised by constrictions. in the marginal part of the sections, short tertiary branches, grouped into bundles, can be seen (fig. 7). both sections show a comparatively small number of primary branches (11-12) per whorl. 7: go-759/3, x22; 10: vt-26/126, x22. 4 palaeodasycladus mediterraneus var. heraki (soka» & nikler, 1966) n. comb. 4 oblique section of a specimen with a micritized region of secondary and tertiary branches. vt-26/25, x22. sample localities and ages vt-26: mali alan pass, central mt. velebit, lower liassic. ob-9619: duπice, central mt. velebit, lower liassic. go-759: rujanska kosa, east of trigonometric point 940, mt. velebit, lower liassic. 191sokaë plate ix 192 geologia croatica 54/2 plate x 1-6 palaeodasycladus mediterraneus var. mediterraneus 1 oblique section of a specimen with entirely preserved central cavity, variously shaped primary branches, clearly phloiophorous secondaries, and strongly swollen tertiaries. tg-9/21, x14. 2 oblique-tangential section of a specimen with short primary branches with variably shaped distal ends. secondary branches, thinner in lower part of the thallus and thicker in the upper part, bear bundles of short, phloiophorous tertiaries. vt-26/375, x17. 3 longitudinal-tangential section, with entire axial cavity and gradational diameter and shape of primary branches from the bottom to the top of thallus. secondary and tertiary branches are phloiophorous. vt26/408, x22. 4-6 oblique sections of specimens in which the different shapes of primary branches, shorter or longer secondary and tertiary branches, more or less clearly grouped into bundles, can produce differences in the appearance of specimens in identically orientated sections. 4: vt-26/111, x34; 5: vt-26/204, x22; 6: go8719, x14. sample localities and ages tg: mt. trnovski gozd, western slovenia, middle liassic. vt-26: mali alan pass, central mt. velebit, lower liassic. go-8719: ivanova draga, central mt. velebit (north of village suπanj), middle liassic. 193sokaë plate x 194 geologia croatica 54/2 plate xi 1-13 palaeodasycladus mediterraneus var. mediterraneus 1 transverse section of a specimen in which some primary branches show incipient ramifications that allow possible interpretation as being very short secondary branches which give rise to thin, acrophorous tertiaries and even quaternaries. note that the branches of the same whorl are not identical. vt-26/229, x17. 2-4 transverse sections. the number of primary branches in a whorl varies from 14-16. 2: vt-26/226, x22; 3: vt-26/166, x22; 4: vt-26/102, x22. 5-8 transverse sections of specimens with variously shaped primary branches. secondary branches are, as a rule, longer than the tertiaries, which are especially short in fig. 6. 5: vt-26/123, x22; 6: vt-26/68, x34; 7: vt26/88, x22; 8: jd-15b, x22. remark: transversal sections are not suitable for reliable determination. thus the section in fig. 6 may possibly belong to p. anae . 9-12 transverse sections of specimens with secondary and tertiary branches varying in size. 9: vt-26/51, x22; 10: tg-9/24, x22; 11: vt-26/273, x17; 12: vt-26/108, x22. 13 transverse section of a specimen with regular branches. secondary branches, all of the same size and shape, bear bundles of short, phloiophorous, tertiaries. ob-9619/21, x22. sample localities and ages vt-26: mali alan pass, central mt. velebit, lower liassic. jd-15b: jadiëevac, central mt. velebit, lower liassic. tg: mt. trnovski gozd, western slovenia, middle liassic. ob-9619: duπice, central mt. velebit, lower liassic. 195sokaë plate xi 196 geologia croatica 54/2 plate xii 1 palaeodasycladus mediterraneus var. heraki (soka» & nikler, 1966) n. comb. 1 oblique tangential section. bundles of secondary branches are clearly visible. vt-26/188, x22. 2-5, 6a palaeodasycladus mediterraneus (pia, 1920) 1927 var. mediterraneus 2-6a oblique sections of specimens with similarly shaped primary branches and visible bundles of secondary branches, giving, seemingly, the appearance of articulation. 2: jd-8/6, x17; 3: tg-9/14, x34; 4: tg-9/10, x34; 5: tg-9/5, x17; 6a: tg-9/17, x34. 6b palaeodasycladus mediterraneus var. gracilis (cros & lemoine, 1967 ex granier & deloffre 1993) n. stat. 6b transverse, somewhat oblique section. tg-9/17, x34. sample localities and ages vt: mali alan pass, central mt. velebit, lower liassic. jd: jadiëevac, central mt. velebit, lower liassic. tg: mt. trnovski gozd, western slovenia, middle liassic. 197sokaë plate xii 198 geologia croatica 54/2 plate xiii 1-3, 6-7 palaeodasycladus mediterraneus (pia, 1920) 1927 var. mediterraneus 1-2 tangential sections with well developed constrictions of secondary and tertiary branches, with apparent articulation of elongated, cylindrical segments. 1: turska 6c/2, x17; 2: turska 6c1, x22. 3 transverse-oblique section of a fragment. constrictions of secondary branches produce the illusion of articulation, e.g. a string of beads. vt-26/160, x22. 6 oblique section. tg-9/25, x22. 7 transverse section. note the extremely short tertiary branches. several of the secondary branches show constrictions, producing a seemingly beaded appearance. vt-26/382, x22. 4-5 palaeodasycladus anae (soka», 1988) n. comb. 4-5 longitudinal-oblique sections. note primary branches of various shape and size. on the left side of the section in fig. 4 groups of cysts in the pores of the primary branches may be seen. this is an enlarged detail of the section figured in pl. viii, fig. 1. 4: vt-26/328, x40; 5: vt-26/263, x17. sample localities and ages turska: kuyubasi-bucak, north antalya, turkey, middle liassic. vt: mali alan pass, central mt. velebit, lower liassic. tg: mt. trnovski gozd, western slovenia, middle liassic. 199sokaë plate xiii 200 geologia croatica 54/2 plate xiv 1-4, 7, 8a, 9 palaeodasycladus mediterraneus (pia, 1920) 1927, var. mediterraneus 1 tangential section, enlarged detail of pl. i, fig. 1. in pores of the primary branches (central part) and secondary branches (lower part) groups of cysts can be seen. secondary branches grow in bundles of 3-4 branches. jd-14/1, x34. 2-4 oblique sections of specimens with thicker secondary branches and short tertiaries. 2: vt-26/360, x17; 3: vt-26/30, x22; 4: vt-26/327, x22. 7 oblique tangential section with comparatively small primary branches arranged in loosely spaced whorls. there are bundles of 4-5 secondary branches per primary branch. 5-6 palaeodasycladus mediterraneus var. heraki (soka» & nikler, 1966) n. comb. 5-6 tangential-oblique sections. rectangular primary branches bear bundles of 4-5 secondary branches. note, in fig. 5, individual cysts in the pores of the primary branches. 5: vt-26/24, x17; 6: vt-26/386, x17. 8b palaeodasycladus barrabei lebouché & lemoine, 1963 ex granier & deloffre, 1993 8b oblique section. vt-26/337, x14. sample localities and ages jd: jadiëevac, central mt. velebit, lower liassic. vt: mali alan pass, central mt. velebit, lower liassic. 201sokaë plate xiv 202 geologia croatica 54/2 plate xv 1, 3-9 palaeodasycladus mediterraneus var. mediterraneus 1, 3-9 oblique sections of specimens with primary and secondary branches of varying size and shape. despite of varying degree of similarity and some common features, no two specimens are identical (sections are similarly oriented). 1: tg-9/7, x17; 3: vt-26/308, x14; 4: tg-9/3, x17; 5: vt-26/78, x22; 6: tg-9/10, x22; 7: tg-9/8. x22; 8: vt-26/369, x22; 9: vt-26/52, x22. 2 palaeodasycladus mediterraneus var. heraki (soka» & nikler, 1966) n. comb. 2 oblique section. rectangular primary branches connect with the central axis through a tiny tubular pore, situated in the middle of the base of the primary branch. vt-26/283, x14. sample localities and ages tg: mt. trnovski gozd, western slovenia, middle liassic. vt: mali alan pass, central mt. velebit, lower liassic. 203sokaë plate xv 204 geologia croatica 54/2 plate xvi 1-8 palaeodasycladus mediterraneus var. gracilis (cros & lemoine, 1967 ex granier & deloffre, 1993) n. stat. 1 longitudinal-oblique tangential section. comparatively thin, acrophorous, primary branches bear bundles of thin secondary branches that are slightly funnel-shaped at their distal ends (e.g. slightly phloiophorous type). primary branches are arranged in comparatively loosely spaced whorls. the specimen may also be regarded as being intermediate between var. gracilis and var. mediterraneus .vt-26/176, x17. 2-3 longitudinal sections. primary branches are more steeply inclined and generally of an acrophorous type. the central cavity is generally preserved, sporadically destroyed by erosion and widening of the basal pores of primary branches. 2: tg-9/22, x34; 3: tg-9/2, x22. 4-5 oblique sections. primary branches tubular, slightly widened (funnel-shaped) distally, bearing thin secondaries. tertiary branches are not clearly visible. 4: tg-9/5, x17; 5: tg-9/10, x43. 6 transverse, slightly oblique section. larger pores correspond to the sections of primary branches, each having bundle of 3-4 secondaries (e.g. smaller pores). tg-9/5, x53. 7-8 oblique sections. in fig. 7, short, tubular primary branches bear thin, longer, acrophorous secondary branches. in fig. 8, bottom, bundles of 3 secondary branches can be seen. 7: tg-9/6, x22; 8: tg-9/18, x34. sample localities and ages tg: mt. trnovski gozd, western slovenia, middle liassic. vt: mali alan pass, central mt. velebit, lower liassic. 205sokaë plate xvi 206 geologia croatica 54/2 plate xvii 1-8 palaeodasycladus mediterraneus var. gracilis (cros & lemoine, 1967 ex granier & deloffre, 1993) n. stat. 1 longitudinal-tangential section. well preserved wall of central cavity, visibly perforated by larger pores of the primary branches. in the tangential part of the section, secondary branches are distinctly acrophorous. tg-9/15, x34. 2-3, 5 oblique sections of specimens with preserved axial cavity and with tubular primary and secondary branches. 2: tg-9/6, x22; 3: tg-9/13, x17; 5: tg-9/2, x22. 4 tangential section. independently of the depth of the section, pores retain the same diameter throughout, indicating their acrophorous nature. tg-9/6, x22. 6 transverse, slightly oblique section. tg-9/2, x43. 7-8 oblique sections of specimens with preserved axial cavity and with acrophorous branches; in fig. 8, primary branches are twice as wide as the secondary. 7: tg-9/3, x43; 8: tg-9, x22. sample localitiy and age mt. trnovski gozd, western slovenia, middle liassic. 207sokaë plate xvii 208 geologia croatica 54/2 plate xviii 1-8 palaeodasycladus mediterraneus var. gracilis (cros & lemoine, 1967 ex granier & deloffre, 1993) n. stat. 1 longitudinal-tangential section. in the bottom part, larger pores of the primary branches are visible in the wall. above them the destruction of these pores produces an illusion of intusannulation. secondary branches are tubular. tg-9/6, x22. 2-7 various oblique sections. in some specimens, tubular primary branches and secondary branches half their with can be observed. 2: tg-9/1, x22; 3: tg-9/3, x43; 4: tg-9/5, x54; 5: tg-9/1, x22; 6: tg-9e/22, x22; 7: tg-9/5, x22. 8 transverse section. larger pores next to the wall of the central cavity correspond to the primary branches which bear 3-4 thin secondary branches. these have a constant diameter along their length, thus being of acrophorous type. 9-12 palaeodasycladus mediterraneus var. elongatulus praturlon, 1966 1 longitudinal-tangential section. axial cavity secondarily widened, due to the destruction of the proximal region of the primary branches. secondary branches are acrophorous and, distally, more steeply inclined upwards. vt-26/220, x14. 10 section of a segment with long, acrophorous secondaries. vt-26/343, x14. 11 tangential section. in larger pores (of the primary branches), individual cysts and smaller groups of cysts can be seen. secondary branches, of acrophorous type, grow out in bundles of 3-4 branches. the outer “feathery” surface results from tightly squeezed segments placed deeply one into another, and with sporadically occurring fissures indicating annulation.vt-26/296, x14. 12 oblique section with contours of segments visible on the outer surface. vt-26/184, x14. sample localities and ages tg: mt. trnovski gozd, western slovenia, middle liassic. vt: mali alan pass, central mt. velebit, lower liassic. 209sokaë plate xviii 210 geologia croatica 54/2 plate xix 1-6 palaeodasycladus mediterraneus var. elongatulus praturlon, 1966 1 oblique section with destroyed proximal region of primary branches. tubular secondary branches are more steeply inclined upwards. possible cysts in partly preserved pores of the primary branches. vt-26/151, x14. 2 tangential section passing into oblique section. in the tangential part of the section, secondary branches grouped into bundles of 3-4 branches can be seen. uneven, “feathery”, outer surface with sporadically preserved fissures relics of annulation) indicates the segmentation in this species. vt-26/102, x14. 3-5 various oblique sections. in fig. 3 note clearly visible fissures separating the segments. the approximately equal diameter of pores indicates acrophorous secondary branches. fissures in the skeleton are also visible in fig. 5. 3: vt-26/280, x17; 4: vt-26/155, x14; 5: vt-26/164, x14. 6 tangential-oblique section. outer surface of the skeleton and visible fissures indicate segmentation, but with tightly squeezed segments. long, acrophorous, secondary branches are more steeply bent in their distal part. vt-26/382, x17. sample localitiy and age mali alan pass, central mt. velebit, lower liassic. 211sokaë plate xix 212 geologia croatica 54/2 plate xx 1-9 palaeodasycladus mediterraneus var. elongatulus praturlon, 1966 1-2 oblique sections. note, in fig. 2, well-preserved cylindrical primary branches from which, without constrictions, secondary branches grow out in bundles of 3-4 branches. 1: vt-26/130, x14; 2: vt-26/293, x17. 3-5 various oblique sections with visible traces of segmentation and with acrophorous, upwards inclined secondary branches. 3: vt-26/158, x14; 4: vt-26/190, x14; 5: vt-26/73, x14. 6 transverse-oblique section with a visible arrangement and number of partly preserved primary branches in a whorl. beside the relics of primary branches, bundles of 3-4 secondary branches can be seen, in which the diameter of the pores decreases in the distal region. vt-26/73, x14. 7 oblique section with secondarily enlarged central cavity and traces of annulation. vt-26/144, x14. 8 fragment with visible globular primary branches and long, acrophorous, secondaries growing out of the primaries without constrictions. go-10096/63, x22. 9 fragment of a distinctly annulated specimen in which the neighbouring segments do not fit snugly against each other. vt-26/36, x22. sample localities and ages vt: mali alan pass, central mt. velebit, lower liassic. go-10096: southern slopes of jasenovaëko brdo (elevation point 1,367), central mt. velebit. 213sokaë plate xx 214 geologia croatica 54/2 plate xxi 1-6 palaeodasycladus mediterraneus var. elongatulus praturlon, 1966 1, 4 tangential-oblique section with partly preserved primary branches and acrophorous secondary branches which are more strongly inclined in their distal part. in the bottom part of the section, traces of segmentation are clearly visible. vt-26/324, x14. 2-3, 5 various oblique sections of specimens with a secondarily enlarged axial cavity and very steeply inclined acrophorous secondary branches, becoming almost parallel to the longitudinal growth axis (these specimens correspond well with those figured by praturlon, 1966, fig. 1). 2: g-3831/10, x26; 3: go-3831/25, x26; 5: go-3831/27, x22. 6 tangential section with clearly marked annulation. jp-61/1, x34. sample localities and ages vt: mali alan pass, central mt. velebit, lower liassic. go-3831: east of ©ariêa duplje, central mt. velebit, lower liassic. jp: on the road to panos, central mt. velebit, lower liassic. 215sokaë plate xxi 216 geologia croatica 54/2 plate xxii 1-7 palaeodasycladus barrabei lebouché & lemoine, 1963 ex granier & deloffre, 1993 1 longitudinal, partly tangential section of a club-shaped and undulated skeleton. the club-shaped form is attained, as in the type-species, by thickening of the wall in the younger part of the thallus. small, stump-like or globular-elliptical primary branches generally stay perpendicular to the axial cavity. secondary branches are generally thin and slightly widened distally; they diverge from each other, being bent both upwards and downwards. the axial cavity is delimited by a smooth and even wall. vt-26/21, x14. 2 oblique tangential section of a curved thallus. primary branches are situated obliquely, as well as the segments between obliquely cut annulations. vt-26/22, x22. 3 oblique section of a skeleton with incompletely developed annulation/fissuration. primary branches perpendicular. intusannulation not developed. 4 longitudinal section of a distinctly annulated skeleton with oblique, stumpy, primary branches, some of which show apparent metaspondility (arrow). distinctly regular intusannulation is developed. possible individual cysts, as well as small groups of cysts, rather numerous in the central cavity, indicate possible endospority in some specimens. vt-26/33, x14. 5 oblique section with larger primary branches. an upper right primary branch suggests possible ramification up to the fourth-order branches. vt-26/41, x20. 6 tangential-oblique section of an annulated specimen with very slightly developed intusannulation and small, bubble-shaped primary branches. vt-26/30, x22. 7 oblique section of a visibly annulated skeleton. some primary branches show possible metaspondility (?) diverging branches. vt-26/27, x22. sample locality and age mali alan pass, central mt. velebit, lower liassic. 217sokaë plate xxii 218 geologia croatica 54/2 plate xxiii 1-12 palaeodasycladus barrabei lebouché & lemoine, 1963 ex granier & deloffre, 1993 1 tangential-oblique section of a specimen with obliquely cut annulation and equally obliquely positioned primary branches. a slightly developed annulation is clearly visible. vt-26/155, x22. 2 longitudinal, deep tangential section with pronounced intusannulation. mutually separated, rounded to elliptical hollow spaces in the middle part of the section correspond to swellings of the axial cavity, whereas the calcareous partitions between the hollow spaces correspond to the centripetal protrusions of the wall, at the bases of which there are pores of primary branches, through which they connect with the central axis. the outer surface shows only a slight undulation. vt-26/64, x17. 3 tangential-oblique section with barely visible annulation and obliquely situated primary branches. vt26/297, x17. 4 oblique tangential section of a specimen with a probably curved thallus and well-developed annulation. vt26/60, x14. 5 tangential section. note the obliquely cut annulation. vt-26/24, x14. 6-8 various oblique, partly tangential, sections of specimens without annulation (fig. 8) or with poorly developed annulation (fig. 6). primary branches differ in detailed morphology and are mostly perpendicularly situated. some primary branches (fig. 6) are heavily deformed. 6: vt-26/267, x17; 7: vt-26/152, x14; 8: vt26/352, x14. 9 oblique section of a distinctly annulated specimen. vt-26/164, x22. 10, 12 tangential sections. fig. 10 shows an undulated specimen with barrel-shaped segments stacked one above the other. fig. 12 shows a distinctly annulated specimen. 10: vt-26/405, x17; 12: vt-26/267, x22. 11 tangential-oblique section with obliquely cut annulations and visible intusannulation. vt-26/167, x17. sample locality and age mali alan pass, central mt. velebit, lower liassic. 219sokaë plate xxiii 220 geologia croatica 54/2 plate xxiv 1-10 palaeodasycladus barrabei lebouché & lemoine, 1963 ex granier & deloffre, 1993 1 longitudinal-tangential section of a curved specimen with annulation developed only in the lower part of the skeleton. bubble-shaped primary branches, situated perpendicular to the longitudinal growth axis, sporadically contain individual cysts. secondary branches, diverging from each other, are of an acrophorous type and bear short, phloiophorous tertiaries. intusannulation is well developed. vt-26/353, x17. 2 enlarged detail of the oblique-tangential section figured in pl. xxiii, fig. 6, showing heavily deformed primary branches. vt-26/267, x34. 3-6, 9 transverse sections, showing, on average, more than 20 primary branches per whorl. 3: vt-26/42, x22; 4: vt-26/436, x17; 5: vt-26/378, x22; 6: vt-26/434, x22; 9: vt-26/262, x17. 7 oblique section of a specimen with distinct annulation, extending deeply into the calcareous skeleton and reaching the wall of the central cavity. vt-26/331, x22. 8, 10 oblique sections of specimens showing distinct annulation and visible intusannulation. it is clearly visible that each segment bears one whorl of branches; secondary and tertiary branches diverge from each other. 8: vt-26/387, x22; 10: vt-26/199, x22. sample locality and age mali alan pass, central mt. velebit, lower liassic. 221sokaë plate xxiv 222 geologia croatica 54/2 plate xxv 1-9 palaeodasycladus alanensis n. sp. 1 holotype. oblique-tangential section. swollen, or bowl-shaped, loosely spaced primary branches give rise, at their borders, to secondary branches. in sections nearer to the central axis, primary branches appear as large, circular pores in some of which cysts can be seen. secondary branches are mutually divergent. vt-26/149, x17. 2-3 fragments of longitudinal sections with bowl-shaped primary branches. fig. 2 is an enlarged detail of fig. 5. 2: vt-26/326, x34; 3: vt-26/162, x22. 4 oblique section of a cylindrical skeleton. primary branches are bushy and directly connected with central cavity; they bear thin, acrophorous secondary branches which are, at their distal ends, divided into tertiary branches. intusannulation is poorly developed. vt-26/16, x14. 5 longitudinal section of a cylindrical skeleton with visible annulation in the lower part and well developed intusannulation. primary branches are bowl-shaped and situated perpendicular to the longitudinal growth axis. vt-26/326, x17. 6, 9 tangential sections. large pores of primary branches are approximately in alternating arrangement. 6: vt26/150, x14; 9: vt-26/201, x14. 7-8 oblique sections with bowl-shaped primary branches. 7: vt-26/403, x22; 8: vt-26/313, x22. sample locality and age mali alan pass, central mt. velebit, lower liassic. 223sokaë plate xxv 224 geologia croatica 54/2 plate xxvi 1-7 palaeodasycladus dolomiticus (cros & lemoine, 1966) n. comb. 1-3 oblique sections. in fig. 1, note finger-shaped secondary branches which produce circular and polygonal pores in tangential sections. each secondary branch bears a bundle of tertiaries. 1: tg-9/25, x22; 2: tg-9/33, x22; 3: tg-9/4, x17. 4, 7 tangential sections showing well developed partitions between densely packed consecutive whorls and rectangular to elliptical pores of primary branches. note, in fig. 7, varying dimensions of primary branches within the same whorl and their elongation in the direction of growth. 4: ob-9619/5, x17; 7: ob-9619, x17. 5-6 transverse sections. finger-shaped secondary branches grow out of distally widened portions of primary branches. in fig. 5, note the varying diameter of the individual primary branches of the same whorl. 5: vt26/149, x14; 6: jd-15/2, x14. sample localities and ages tg: mt. trnovski gozd, western slovenia, middle liassic. ob-9619/9: duπice, central mt. velebit, lower liassic. jd: jadiëevac, central mt. velebit, lower liassic. vt: mali alan pass, central mt. velebit, lower liassic. 225sokaë plate xxvi 226 geologia croatica 54/2 plate xxvii 1a, 2-3a, 4-8 palaeodasycladus dolomiticus (cros & lemoine, 1966) n. comb. 1a transverse section. primary branches with distally widened portions, out of which the finger-shaped secondaries emerge. ob-9619/27, x17. 2 oblique section. densely packed consecutive whorls are separated by thin partitions. vt-26/327, x14. 3a part of a longitudinal-tangential section of a specimen with slightly oblique branches. vt-26/400, x17. 4 oblique section. note distinctly large rectangular branches. outer surface of the skeleton is heavily abraded. jd-15a, x17. 5 oblique tangential section. vt-26/189, x14. 6 oblique tangential section of a specimen in which secondary and tertiary branches gradually become more and more steeply inclined upwards. vt-26/264, x17. 7-8 oblique sections. large rectangular, primary branches are situated obliquely to the longitudinal growth axis. 7: ob-9619/30, x17; 8: jd-15, x14. 1b, 3b palaeodasycladus mediterraneus var. mediterraneus 1b oblique section. ob-9619/27, x17. 3b oblique section. vt-26/400, x17. sample localities and ages ob-9619: duπice, central mt. velebit, lower liassic. jd: jadiëevac, central mt. velebit, lower liassic. vt: mali alan pass, central mt. velebit, lower liassic. 227sokaë plate xxvii 228 geologia croatica 54/2 plate xxviii 1-9 palaeodasycladus anae (soka», 1988) n. comb. 1 longitudinal section. note variously shaped and variously large primary branches within the same whorl. vt-26/417, x34. 2 oblique section. different primary branches. some secondary branches grow out from lateral surfaces of the primary branches, whereas other secondary branches grow out from variously shaped distal ends of the primaries. secondary branches are phloiophorous. vt-26/275, x22. 3 oblique section. irregular branches with variously shaped distal ends from which short, horn-shaped protrusions and secondary branches grow out in a finger-like way. vt-26/275, x22. 4 oblique section. different primary branches lined up along the thallus; at their distal ends, they bear hornor nipple-like protrusions (second-order branches?). some primary branches lack such protrusions. vt-26/29, x34. 5 oblique section. predominantly fusiform (spindle-shaped) primary branches (uragiellatype) pass into irregular and nodular ones and those with an incision at the distal end. vt-26/403, x34. 6 longitudinal-oblique section. predominantly nodular primary branches, some of which bear, at their distal ends, nipple-like protrusions that give rise to the secondary/tertiary branches. vt-26/45, x34. 7 longitudinal section. along the thallus, there are variously shaped primary branches: nodular in the lower part, fusiform (spindle-shaped; uragiella -type) in the middle part, and sporadically physoporella -like in the upper part. vt-26/319, x44. 8 oblique section. predominantly nodular primary branches; from their distal ends, bundles of secondary branches grow out from a common base. vt-26/209, x44. 9 oblique section. nodular primary branches; some are divided at their distal ends, into two equal forks (in the plane of section), each bearing a bundle of secondary/tertiary phloiophorous branches. vt-26/121, x34. sample locality and age mali alan pass, central mt. velebit, lower liassic. 229sokaë plate xxviii 230 geologia croatica 54/2 plate xxix 1-7 palaeodasycladus anae (soka», 1988) n. comb. 1 longitudinal section. primary branches vary in shape, particularly differing in their distal ends, which sometimes pass into nipple-like or, more often, horn-shaped protrusions, which, in turn give rise either to single secondary/tertiary branches or to bundles of these. whether they should be called secondary or tertiary (or second-order and third-order) branches depends on how we conceive the horn-like protrusions, i.e. what status is given to them. single cysts may be seen in the pores of the primary branches or they may be dispersed in the central cavity. vt-26/115, x34. 2-3 tangential-oblique sections of specimens with different primary branches, some of which bear nippleor horn-shaped protrusions at their distal end. the central cavity lacks intusannulation and is clearly delineated by an even and smooth wall. primary branches are slightly oblique to the longitudinal axis of growth. 2: vt26/290, x14; 3: vt-26/83, x14. 4 oblique section. primary branches of the some whorl show various forms and degrees of ramifications. the branch in the upper left corner ramifies into two visible forks (possibly more), each bearing a bundle of secondary/tertiary branches which divide distally. in some pores of primary branches cysts are visible. vt26/342, x34. 5 part of an oblique section. predominantly nodular primary branches with different distal ends. vt-26/395, x34. 6-7 oblique sections of specimens with differently shaped primary branches and a well preserved, uninterrupted axial cavity. 6: vt: 26/426, x22; 7: vt-26/56, x14. sample locality and age mali alan pass, central mt. velebit, lower liassic. 231sokaë plate xxix 232 geologia croatica 54/2 plate xxx 1-7 palaeodasycladus anae (soka», 1988) n. comb. 1-2 oblique sections. figured specimens show variously shaped primary branches, which are particularly visible in the tangential parts of sections (upper part of figures). in fig. 1, note the preserved uninterrupted wall of the central cavity, perforated by the entrance pores of the primary branches. depending on the shape of their distal ends, primary branches bear one or more bundles of secondary branches (up to two in the plane of section). some branches ramify up to the fourth-order branches. 1: vt-26/8, x22; 2: vt-26/269, x17. 3-7 oblique sections of specimens with visibly different primary branches. ramification may proceed up to the thirdand fourth-order branches. all specimens show a well preserved, uninterrupted central cavity with more or less visible entrance pores or larger openings at the proximal base of the primary branches. 3: vt26/314, x17; 4: vt-26/389, x34; 5: vt-26/454, x22; 6: vt-26/362, x17; 7: vt-26/3, x17. sample locality and age mali alan pass, central mt. velebit, lower liassic. 233sokaë plate xxx 234 geologia croatica 54/2 plate xxxi 1-8 palaeodasycladus mediterraneus var. calciticus n. var. 1 oblique section. vt-26/322, x14. 2 tangential-oblique section of a specimen with well-developed calcareous partitions between neighbouring whorls. distally widened dark pore indicates the expanding bundle consisting of 3-4 secondaries. vt26/120, x22. 3 holotype, oblique section. well developed partitions between branches of the neighbouring whorls. below the axial cavity, some preserved individual envelopes of primary and secondary branches or their traces delineating their square shape may be seen. incomplete calcification of branches, with only traces of calcification in the spaces between the secondary branches, does not provide insight into their shape and mutual relationship. porous structure is preserved only in the peripheral part of the thallus. vt-26/379, x17. 4, 7 longitudinal sections of partly destroyed and secondarily enlarged axial cavities. well developed calcareous partitions are more or less perpendicular to the logitudinal axis of growth. 4: vt-26/263, x17; 7: vt-26/399, x14. 5 tangential section. vt-26/54, x22. 6, 8 differently oriented oblique sections. calcareous partitions are clearly visible. note, in fig. 8, the partly preserved shape of a primary branch and further ramification within the individual envelope of each branch. in the lower left part, note the bundle of 3-4 secondary branches. 6: vt-26/123, x22; 8: vt-26/205, x14. sample locality and age mali alan pass, central mt. velebit, lower liassic. 235sokaë plate xxxi 236 geologia croatica 54/2 plate xxxii 1-8 palaeodasycladus mediterraneus var. calciticus n. var. 1 oblique section of a specimen with typically developed calcification without clearly visible branches. vt26/259, x17. 2, 5 parts of tangential sections with clearly developed calcareous partitions between the branches of neighbouring whorls. note, in fig. 2, bottom, sporadically developed calcification protruding between secondary or tertiary branches. 2: vt-26/305, x17; 5: vt-26/404, x22. 3, 6 oblique, partly tangential sections with well developed, slightly inclined, calcareous partitions. in fig. 3, bottom and fig. 6 top, there are more or less clearly delimited pores of envelopes containing 3-4 contours of sections of secondary branches. 3: vt-26/438, x17; 6: lost slide, x17. 4 oblique sections of strongly developed calcification of the envelope. sporadically, one can see calcitic wedges and small, irregular, calcitic masses representing relics of isolated, mutually disconnected fillings (hanging calcite in the text) in the cavities between the branches within the same envelope. vt-26/87, x14. 7 tangential sections with clearly delineated envelopes of the branches, within which 3-4 non-calcified secondary branches can be seen. vt-26/330, x17. 8 oblique section. vt-26/330, x17. sample locality and age mali alan pass, central mt. velebit, lower liassic. 237sokaë plate xxxii 238 geologia croatica 54/2 plate xxxiii 1-8 palaeodasycladus multiporus n. sp. 1 oblique, recrystallised section. vt-26/46, x22. 2 longitudinal-oblique section. rectangular primary branches bear numerous secondaries. note the ramification of branches up to the third order. go-10096/6, x22. 3, 5, 7-8 oblique sections of specimens with numerous secondary and tertiary branches. fourth-order ramification possibly occurs. note characteristic lack of bundles of secondary branches in the basal part of their growth. 3: vt-26/68. x34; 5: vt-26/54, x22; 7: vt-26/448, x22; 8: vt-26/104, x22. 4, 6 oblique sections. large, rectangular primary branches bear up to 5 secondary branches (in the plane of section). in fig. 4, the ramifications up to the fourth order may be supposed. 4: go-100096, x22; 6: vt-26/27, x22. sample localities and ages go: 10096: southern slopes of jasenovaëko brdo (elevation point 1,367), central mt. velebit, lower liassic. vt: mali alan pass, central mt. velebit, lower liassic. 239sokaë plate xxxiii 240 geologia croatica 54/2 plate xxxiv 1-8 palaeodasycladus multiporus n. sp. 1 oblique-tangential section. vt-26/351, x17. 2 holotype, oblique section. quadrilateral, obliquely situated primary branches bear numerous secondary branches, which, in this species, characteristically are not grouped into bundles at the base of their growth. vt-26/262, x17. 3-4 oblique section. in fig. 4, upper right part, up to 6 secondary branches may be seen through one primary branch (in the plane of section). ramification up to the fourth order is possibly present. central cavity in both specimens characterised by an uninterrupted wall. 3: vt-26/319, x22; 4: vt-26/343, x22. 5, 7-8 oblique sections of comparatively poorly preserved specimens. ramification up to the fourth-order branches may be barely discerned. large primary branches seem to bear rather numerous secondary. 5: vt-26/201, x17; 7: vt-26/303, x14; 8: vt-26/448, x22. 6 oblique section. in this specimen, primary branches are somewhat more narrow and more steeply inclined; they bear numerous, thin secondary branches. ramification up to the fourth order is indicated. vt-26/77, x17. sample locality and age mali alan pass, central mt. velebit, lower liassic. 241sokaë plate xxxiv 242 geologia croatica 54/2 plate xxxv 1-6 palaeodasycladus benceki n. sp. 1 longitudinal section of a specimen with very large primary branches, that are, moreover, elongated in the direction of growth. whorls of primary branches are densely packed. central cavity is straight. vt-26/192, x14. 2 oblique-tangential section of a specimen with large, bubble-shaped, primary branches, that are situated somewhat more apart from each other. the distal surface is very irregular and as is the growth of the secondary branches, which may also grow out from lateral surfaces. in some cavities of the primary branches, poorly preserved cysts can be seen. vt-26/260, x17. 3 oblique section of a specimen with very large and irregular primary branches and with rugged distal surfaces. in the pores, cysts are sporadically preserved. the outer surface of the skeleton is characterised by fissuration to shallow annulation. the inner wall is even, perforated by comparatively large entrance pores. vt-26/416, x17. 4 transverse section. primary branches are 9-10 in a whorl and may be variously shaped and of differing dimensions. in the left centre, note the growth of a secondary branch from the proximal lateral side of a primary branch. vt-26/361, x22. 5 longitudinal section of a specimen with large and irregular primary branches which bear comparatively short secondary branches which, in turn, may be supposed to branch off distally into tertiary branches. axial cavity is preserved, with clear intusannulation. vt-26/203, x14. 6 tangential section of a specimen with large primary branches, arranged alternately in neighbouring whorls. vt-26/43, x22. sample locality and age mali alan pass, central mt. velebit, lower liassic. 243sokaë plate xxxv 244 geologia croatica 54/2 plate xxxvi 1-7 palaeodasycladus benceki n. sp. 1 longitudinal oblique section of a specimen with very large and elongated (in the direction of growth) primary branches. vt-26/223, x17. 2 holotype; oblique section. primary branches are distinctly large and visibly irregular at their distal ends. vt26/436, x22. 3 oblique section with distinctly irregular primary branches. vt-26/374, x22. 4 oblique section with partly destroyed region of the primary branches. secondary branches also grow out from the lateral sides of the primary branches, producing tiny pores of secondary branches arranged around the large pores of the primary branches. vt-26/221, x17. 5 oblique section. primary branches of various shapes and varying dimensions. note, at the bottom, large pores of primary branches surrounded by tiny pores of secondary branches. in spite of the possible visual illusion, sterile branches do not exist. vt-26/331, x17. 6 transverse section of a poorly preserved recrystallised specimen. note the irregular, rough distal surface of the primary branches. vt-26/291, x22. 7 oblique section with distinctly irregular primary branches and with secondary branches growing out of the lateral proximal surfaces of the primaries. vt-26/405, x22. sample locality and age mali alan pass, central mt. velebit, lower liassic. 245sokaë plate xxxvi 246 geologia croatica 54/2 plate xxxvii 1-7 palaeodasycladus benceki n. sp. 1 oblique section of a specimen with large, comparatively regular primary branches arranged in densely spaced whorls. on the outer surface of the skeleton, fissuration to shallow annulation can be seen. vt26/444, x17. 2-3 oblique sections near to the horizontal plane. large and irregular primary branches bear secondary branches on the edges of their distal ends (fig. 2 left centre), which appear as tiny pores at the edge of a primary branch in the lower part of the section in fig. 3. this may give a visual illusion of there being sterile branches arranged as in chinianella . 2: vt-26/303, x17; 3: vt/378, x17. 4 oblique-longitudinal section of a specimen with large, irregular and mutually different primary branches. some primary branches in the lower part of the thallus appear, by their shape and dimensions, similar to the branches in p. barrabei . the central cavity shows distinct intusannulation; entrance pores to the branches are situated at or immediately below the narrowest place. vt-26/243, x17. 5, 7 oblique sections of specimens with strongly irregular primary branches and secondary branches growing out from different parts of the primaries. note, in fig. 7 (right side), secondary branches growing out of lateral parts of the primaries. 5: vt-26/323, x17; 7: vt-26/301, x17. 6 transverse section. primary branches (9 in a whorl) are elliptical, elongated in the direction perpendicular to the direction of growth. vt-26/268, x17. sample locality and age mali alan pass, central mt. velebit, lower liassic. 247sokaë plate xxxvii 248 geologia croatica 54/2 plate xxxviii 1-8 forms belonging to the phyletic lineage p. barrabei p. alanensis p. benceki 1 oblique section of p. barrabei with distinct intusannulation and stick-like to stumpy primary branches. vt26/224, x17. 2 oblique section of p. barrabei with very well developed intusannulation and with primary branches showing the tendency of bubble-shaped swelling. 3 longitudinal section of p. barrabei with primary branches showing both swellings and deformations. note the double wall of the central cavity. vt-223, x14. 4 oblique section of p. alanensis with swollen primary branches showing the distinct tendency of becoming bowl-shaped. vt-26/343, x17. 5 oblique tangential section of p. alanensis with swollen, bubble-shaped, primary branches that produce large, alternatingly arranged pores in the tangential part of the section. note very slight intusannulation. vt26/149, x17. 6 oblique section of p. alanensis with slightly developed intusannulation and bush-like widened primary branches. three orders of branches are visible, the secondary branches being distinctly acrophorous. vt26/16, x14. 7 oblique section of p. benceki with visibly increasing diameter and degree of deformation of primary branches, passing upwards from the basal part of the thallus. vt-26/379, x14. 8 longitudinal-tangential section of p. benceki showing the increasing diameter and changing shape of the primary branches from the lower to the upper part of the thallus. the lowest visible branches are typical of p . barrabei . vt-26/417, x17. sample locality and age mali alan pass, central mt. velebit. lower liassic. 249sokaë plate xxxviii 250 geologia croatica 54/2 plate xxxix 1-6 palaeodasycladus asteriscus n. sp. 1 oblique, partly longitudinal section. oblique primary branches are situated in distinctly spaced whorls. note partial grouping of the secondary branches in the upper part, which does not occur in the lower part of the thallus. jd-13, x14. 2-3 oblique sections. note some secondary branches of the same primary branch growing in opposite directions. secondary branches are not grouped into bundles. the separation of the secondary branches is marked by a large pore with small radial channels (tubules; fig. 3, upper part). 2: jd-6b/5, x17; 3: jd-14c, x22. 4-6 oblique sections with a partly visible radial arrangement of secondary branch tubules (at the level of where they grow out from the primary branches). in fig. 5, in the central part of the wall of the cylindrical skeleton, note an indication of a fissure produced by contact of branches of neighbouring whorls, directed in opposite directions. 4: jd-13/14, x22; 5: jd-4c, x17; 6: jd-13/8, x17. sample locality and age the road east of jadiëevac (elevation point 1,274), central mt. velebit, lowermost liassic (hettangian). 251sokaë plate xxxix 252 geologia croatica 54/2 plate xl 1-9 palaeodasycladus asteriscus n. sp. 1 longitudinal-tangential section. jd-13/13, x17. 2-4 oblique sections. in fig. 2, upper part, note the tubules of secondary branches suggesting their approximately perpendicular position to the primary branch. 2: jd-13/22, x17; 3: jd-6b/3, x17; 4: jd-6b/4, x17. 5-9 transverse sections. note, in figs. 6 and 7, an incipient fissure as a result of the direction of growth of secondary branches. 5: jd-13/21, x22; 6,8: jd-13/25; 6: x22; 8: x17; 9: jd-13/9, x22. sample locality and age the road east of jadiëevac (elevation point 1,274), central mt. velebit, lowermost liassic (hettangian). 253sokaë plate xl 254 geologia croatica 54/2 plate xli 1-9 eodasycladus ogilviae cros & lemoine, 1966 1 oblique section. shallow fissuration of the outer surface produces a barrel-shaped appearance of segments. in the lower parts of the thallus, both primary and secondary branches are of p. barrabei -type; passing upwards, some secondary branches become swollen and bubble-shaped. vt-26/401, x17. 2 oblique section. outer surface of the skeleton is slightly undulated to shallowly fissurated. intusannulation is poorly developed; secondary branches become swollen and bubble-shaped in the upper part of the thallus. vt-26/264, x14. 3 tangential section of a specimen with irregularly distributed larger pores, supposedly produced by some swollen bubble-like, secondary branches. vt-26/292, x22. 4 tangential section of e. ogilviae (?). jd-4b/6, x14. 5 oblique section of e. ogilviae (?). swollen branches assume a regularly alternating arrangement in neighbouring whorls only in the upper part of the thallus. one cannot tell with certainty whether these are swollen primary or secondary branches. vt-26/193, x14. 6 longitudinal section of a specimen with poorly developed intusannulation and slight undulation of the skeleton. some secondary branches are bubble-like and swollen. vt-26/202, x22. 7 oblique section of a specimen in which some secondary branches are swollen and produce large pores. vt26/30, x22. 8-9 oblique-tangential sections. note some swollen bubble-like, secondary branches and, in fig. 9, some bubble-shaped swellings (sporangia?), located in the middle of a bundle. sample locality and age vt: mali alan pass, central mt. velebit, lower liassic. jd: the road east of jadiëevac (elevation point 1,274), central mt. velebit, lowermost liassic (hettangian). 255sokaë plate xli 256 geologia croatica 54/2 plate xlii 1-3 selliporella? problematica n. sp. 1 tangential-oblique section. obliquely cut annular depressions are well developed. note, in right centre, a ramified branch with a bag-shaped swelling on the lower side. in this part of the section, outer rims of the segments show a tendency of widening, suggesting distal widening of the secondary branches, or, perhaps, the existence of tertiary branches. note, also, a reduced number of pores in the tangential section of the lower segments. t-26/400, x17. 2-3 longitudinal-oblique (fig. 2) and oblique (fig. 3) sections. 2: vt-26/208, x14; 3: vt-26/279, x22. 4-8 humiella japodica n. sp. 4 oblique section. large branches distally become narrower (in the outer half) and separate from each other. jd-13/33, x34. 5 deeper tangential section, cutting through the level of maximum diameter and mutual contact of the branches. in some pores of the alternately arranged branches, dark circular sections suggest the presence of cysts. jd-13/40, x42. 6 holotype a very slightly oblique section. in the envelopes of the branches (upper part of the figure), tubules perforating the envelope can be seen. jd-13/14, x42. 7-8 oblique sections. note, in fig. 7, the piriform shape of the branches and their individuality in the outer part and the perforations of the envelope (upper part of the figure). fig. 8 is a heavily recrystallized specimen. sample localities and ages vt-26: mali alan pass, central mt. velebit, lower liassic. jd-13: jadiëevac (elevation point 1274), central mt. velebit, lower liassic. 257sokaë plate xlii 258 geologia croatica 54/2 1. introduction paratethys was the intercontinental bioprovince, which began to evolve in the oligocene due to the counterclockwise rotation of africa that caused the closure of the tethys ocean. it extended from the western molasse basin in switzerland and the rhone basin in france towards lake aral in asia. paratethys is subdivided into western paratethys, central paratethys and eastern paratethys. the central paratethys extended from bavaria to the carpathian mountain chain (laskarev, 1924; sene©, 1979; steininger & rögl, 1979, 1984; rögl & steininger, 1983, 1984; rögl, 1998, 1999) (fi g. 1). the nature of the evolution of central paratethys and the occurrences of an endemic fauna has necessitated the establishment of local miocene stages (fig. 2). in the geotectonical sense, the largest part of central paratethys is represented by the pannonian basin system, formed due to continental collision and subduction of the european plate under the african (apulian) plate (horváth & royden, 1981; royden, 1988; tari et al., 1992; horváth, 1995; ková» et al., the south-western boundary of central paratethys davor paveli∆ 1998). the pannonian basin system is surrounded by the alps and carpathian mountains, and by the dinarides which existed as land between the mediterranean sea and pannonian basin system during its evolution. the southwestern part of the pannonian basin system consists of the north croatian basin and the northern bosnia region (paveli∆, 2001). the dinarides represent a mountain complex, which formed during the tertiary and quaternary due to tectonic activity, which caused disintegration and uplift of the mesozoic carbonate platform. in the tertiary, compressive movements culminated with orogenesis of the dinarides. further neotectonic activity caused uplift and transpressive deformations of the older structure. these tectonics strongly controlled the formation of many small neogene basins within the dinarides which were characterized by fresh-water sedimentation and an endemic fauna. that tectonic activity has been strongest along the recent eastern adriatic coast due to the continental collision of the adriatic microplate and the dinarides. this collision caused the compression and uplift of blocks which is represented by a mountain chain known as the high karst belt, the highest peaks of which reach from 1400-1913 m (bahun, 1974; pape©, 1985; herak, 1986, 1991, 1999; aljinovi∆ et al., 1987; bla©kovi∆, 1991, 1998, 1999; herak & tomi∆, 1995; marin»i∆ et al., 1977; mati»ec et al., 1997, 2001; pami∆ et al., 1998; dragi»evi∆ et al., 1999; kuk et al., 2000; dragi»evi∆, 2001). several papers deal with the palinspastic reconstruction of central paratethys, or some parts of it during it’s evolution (steininger & rögl, 1979, 1984; rögl & steininger, 1983, 1984; marinescu, 1992; k o v a » et al., 1998, 2001; rögl, 1998, 1999; magyar et al., 1999; gulyás, 2000; paveli∆, 2001). in some of these articles the southwestern central paratethys boundary was constructed in the area of north bosnia and central croatia. however, these boundaries were not located in detail, and are, in part, incorrect due to a lack of data from this area, and a language problem. the locations of these boundaries also imply that the neogene fresh-water basins within the dinarides do not belong to central paratethys, neglecting the view of ani∆ (1951-1953), who suggested that these basins might be a part of that realm during sarmatian time. the correlation of neogene sediments and fauna of fresh-water basins within the dinarides with geologia croatica 55/1 83 92 4 figs. zagreb 2002 key words: neogene, dinarides, central paratethys, mediterranean. institute of geology, hr-10000 zagreb, sachsova 2, croatia; e-mail: dpavelic@igi.hr abstract small neogene basins within the dinarides were never invaded by marine transgressions during their evolution. the fresh-water sedimentation, endemic fauna and their position between the adriatic region and the pannonian basin system explain why these basins have not been considered as parts of the mediterranean or central paratethys realm. the correlation of sediments and fauna of these fresh-water basins with the pannonian basin system and adriatic region suggests that dinaridic fresh-water basins may be considered as a part of the central paratethys. this consideration locates the southwestern boundary of central paratethys within the high karst belt. 84 geologia croatica 55/1 the north croatian basin and northern bosnia region, and with the adriatic region, supports the suggestion that these fresh-water basins may be considered as a part of central paratethys, although there was no marine sedimentation. 2. the north croatian basin and northern bosnia region the evolution of the north croatian basin and northern bosnia region, as a part of the marginal zone of the pannonian basin system was generated by continental rifting processes. the main depressions in this area represent elongated half-grabens formed by tectonic subsidence along the listric faults and strike-slip faults (tari & pami∆, 1998; lu»i∆ et al., 2001; paveli∆, 2001). formation of the north croatian basin and northern bosnia region started in the ottnangian, with fresh-water deposition. the first phase was characterized by accumulation of coarse-grained breccias and conglomerates, with subordinate sandstones and siltstones. deposition took place in braided alluvial fans, which were strongly influenced by synsedimentary tectonics (paveli∆ & kova»i∆, 1999). in the central part of mt. papuk a salina-type lake developed (©∆avni»ar et al., 1983). during the second sedimentation phase a hydrologically open fresh-water lake was formed in this area (k o c h a n s k y d e v i d é, 1979; paveli∆, 2001; paveli∆ et al., 2001), in which silts and sands with sporadic layers of gravel were deposited, together with peats along the lake margins. the lake had an endemic fauna of molluscs and ostracods, such as c o n g e r i a f u c h s i, u n i o sp., and h e t e r o c y p r i s sp. (fig. 3). lacustrine deposits contain remnants of mammalian species prodeinotherium bavaricum , gomphotherium angusti d e n s and brachypotherium brachypus (radov»i∆ et al., 1998). during karpatian time lacustrine conditions were replaced by marine environments due to a minor marine transgression caused either by the opening of a paratethyan seaway to the mediterranean as a consequence of the tectonic activity within the dinarides (s t e i n i nger & rögl, 1979; hamor & szentgyörgyi, 1981; rögl & steininger, 1983, 1984; rögl, fig. 1 location of the central paratethys. 1 9 9 8), or eustatic sea level rise (kova» & h u d a »k o v a, 1997; kova» et al., 2001). deposition was characterized mainly by marls and silts with temporary input of coarse-grained siliciclastics into the basin, and sandy facies in the coastal environments (paveli∆ et al., 1998). the marine regime is indicated by foraminiferal and mollusc associations which are presented by pappina bononiensis , quinqueloculina triangularis , quinqueloculina akneriana , ammobaculites aggluti n a n s, triloculina scapha , dorothia gibbosa , a m m o n i a b e c c a r i i , elphidium macellum and others (fig. 3). during ottnangian and karpatian time volcanic activity gradually increased, from pyroclastics to trachyandesites (shoshonites) (p a m i ∆ et al., 1992/1993; paveli∆, 2001). marine environments continued into the badenian. the early badenian was characterized by a sea-level rise well correlated with the global sea-level rise at the beginning of the middle miocene (rögl & steininger, 1983; haq et al., 1987; steininger e t al., 1989; rögl, 1996, 1998; kova» & huda»kova, 1997; paveli∆ et al., 1998). coarse-grained sili ciclastic material was transported into shallow marine environments, and also to the relatively deeper marine environments, where marls and gravelly calcarenites were deposited (paveli∆ et al., 1998; veli∆ et al., 2000). favourable ecological conditions resulted in expansion of shallowand deep-water benthic and planktonic species, such as amphistegina sp., lenticuli na cultrata , cibicidoides ungerianus , uvigerina pyg m o i d e s, globigerina praebulloides , g l o b i g e r i n o i d e s trilobus a n d preaorbulina glomerosa (fig. 3). intense volcanism produced sequences a few hundred metres thick in some places. during the late badenian, the last miocene marine transgression flooded this area. it was connected with the broad re-opening of the indo-pacific seaway (rögl & steininger, 1983, 1984; st e i ninger et al., 1988; rögl, 1996, 1998), and coincides with a temporary sea-level rise at 13.4 ma (haq et al., 1987). sedimentation was similar to that during the early badenian. the most important late badenian species are bolivina dilatata , pappina neudorfensis , ammonia beccarii and spirorutilus carinatus . due to the beginning of the isolation of the basin during the sarmatian, brackish-water environments developed, resulting in deposition of shallow water gravel, biocalcarenites and limestones, and general dominance of fine-grained deposits in the deeper parts of the basin. typical sarmatian foraminiferal species are elphidium macelum, elphidium josephinum, a n o m alinoides badenensis and porosononion granosum . ervilia dissita dissita , musculus sarmaticus a n d c a r d i um vindobonense belong to the molluscan association. in the early pannonian the environment became “caspi-brackish”, locally even fresh, followed by expansion of endemic species of molluscs and ostracods, as a consequence of definite basin isolation (steininger et al., 1988). the pannonian deposits consist of littoral lacustrine limestones, and deep water marls. the pannonian fossil association contains radix croati ca , congeria banatica , clivunella sp. and hemicytheria c r o a t i c a . in the pontian a gradual shallowing took place, reflected by increased terrigenous material. the species are also endemic, including paradacna okrugici , paradacna abichi , congeria croatica and c o n g e r i a rhomboidea. 3. dinaridic fresh-water basins the neogene basins in the dinarides, i.e. in bosnia and herzegovina and in central and southern croatia, represent depressions generated by tectonics (figs. 1 and 4). they started to form at the end of the palaeogene and 85paveliê: the south-western boundary of central paratethys fig. 2 chronostratigraphic correlation of the mediterranean and central paratethys miocene, and calcareous nannoplankton biozonation (after rögl, 1996, and berggren et al., 1995). 86 geologia croatica 55/1 fig. 3 geological columns of the north croatian basin (pannonian basyn system), sarajevo-zenica basin and livno-duvno basin (dinaridic fresh-water basins), and koraljka-i well (adriatic region). i 'i~~ i i n~~ft • i q : i j i ~ j i : j ~ i ~ : ~ i! i ~ ~ ,iii z lui ! i 0:00 ~ i : ~ i i [). a ~ '. , i i)! di:: i • 0(1: i: • • i i ~ [)<; 0() i :: : i o· ~ , +. i i ~ . • {f~ i' + . i i _!q i' :_n i "'ll'iii ~ _;r{i lilltii'lll iil l 1 87paveliê: the south-western boundary of central paratethys continued to evolve through the neogene. the time of onset and the end of evolution of different basins was unequal, as was subsidence which varied from a few hundred to a few thousand metres in the deepest depressions (pape©, 1985). these basins occur in many areas, with dimensions which range from a few kilometres up to 70 km long and 18 km wide, such as the sarajevo-zenica basin in central bosnia (fig. 4). basins were temporarily connected during their evolution, and occupied much wider areas than at present (juri©i∆pol©ak & sli©kovi∆, 1988). however, the strong neotectonic activity generated by the continental collision of the adriatic microplate and the dinarides caused uplifting of the dinarides to the recent elevations, erosion of the neogene sediments, and reduction of the dimensions of fresh-water basins (pape©, 1985; aljinovi∆ et al., 1987; bla©kovi∆, 1991, 1998, 1999; mati»ec et al., 1997, 2001; pami∆ et al., 1998; dragi»evi∆ et al., 1999; kuk et al., 2000; dragi»evi∆, 2001). thicknesses of the neogene deposits in fresh-water basins vary from a few hundred metres to 1900 m in the livno-duvno basin and 2600 m in the sarajevo-zenica basin (fig. 4). siliciclastics dominate but marls and fig. 4 approximate locations of the south-western shoreline of the paratethyan sea, and the south-western boundary of central paratethys. 88 geologia croatica 55/1 limestones also occur. some sediments are coal-bearing (fig. 3). neogene basins in this area were of fresh-water. some sediments are determined as alluvial, lacustrine, or marsh and swamp, but there have been no detailed sedimentological data. the main geological problem of these basins is the dating of sediments. basins did not have any connection with the sea during their evolution, and endemic species with no chronostratigraphic value developed. therefore, the neogene is subdivided on the basis of local mollusc and ostracod associations, superposition, lithostratigraphic correlation, flora, and occasional mammal occurrences (fig. 3). however, these stratigraphic interpretations are almost highly speculative, sometimes very confusing, and partly incorrect, and are therefore of little use for detailed correlations with central paratethys and mediterranean stages. neogene sediments overlie the pre-neogene basement or oligocene deposits, and are characterised by frequent lateral and vertical variations, and different sedimentary thicknesses as a result of the independent local basin evolution. columns for the sarajevo-zenica and livno-duvno basin are shown in fig. 3. the following general description of sediments and fossil associations is summarized from several works, without a critical stratigraphic approach (s o k l i ∆, 1957; »i»i∆ & milojevi∆, 1977; pape©, 1975; æivanovi∆ et al., 1975; marin»i∆ et al., 1977; jovanovi∆ et al., 1978; kochansky-devidé, 1976; kochansky-devidé & sli©kovi∆, 1978; pami∆ et al., 1978; pol©ak et al., 1978; soka», 1980; juri©i∆-pol©ak, 1984; rai∆ et al., 1984; æagar-saka» & saka», 1984; juri©i∆-pol©ak & sli©kovi∆, 1988; ©u©njara & saka», 1988; juri©i∆-pol©ak et al., 1993; oluji∆, 1999). the oldest neogene sediments are dated as the upper part of the oligo-miocene. siliciclastics predominate, the most frequent include conglomerates, sandstones, marls and clays. characaean limestones and coal beds occur sporadically. a mollusc association c o n t a i n s helix rugulosa , helix geniculata , l y m n a e a s o c i a l i s, lymnaea dilatata , p l a n o r b i s sp. and p i s i d i u m sp. lower miocene sediments are more widespread than oligo-miocene ones. they consist of clays, limestones, marls, sandstones, conglomerates and coal intercalations. tuff is found in some basins. dacite-andesite tuff beds in the sinj basin are interpreted as a consequence of volcanic activity in bosnia (©u©njara & ©∆avni»ar, 1974) (fig. 4). a fossil association is very rich in lower miocene sediments. molluscs are represented by congeria pernaeformis , congeria jad r o v i, orygoceras corniculum , lymnaea dilatata , l y m naea socialis , sphaerium sp., unio sp., helix sp., bythi n e l l a sp., planorbis obtusus and planorbis subcingula t u s. floral species include carpolithes floveatus, g l y p tostrobus europeus , c i n n a m o m u m sp. and c e r a t o p h y l lum sinjanum. mammalian species, such as d y n o t h e r i um bavaricum, occur. the middle miocene sediments show a low degree of diagenesis. during the middle miocene marls, limestones, sandstones, clays and conglomerates were deposited. coal beds occur in some places, pyroclastics too. the most frequent molluscs belong to the genus conge r i a : congeria pernaeformis , congeria jadrovi , c o n g e ria dalmatica , congeria drvarensis , congeria bosni a c a , congeria bihacensis etc. gastropods include o r y goceras bifrons , planorbis cornu , clivunella katzeri, fossarulus tricarinatus , prososthenia schwartzi , m e l a nopsis geniculata , melanopsis inconstans, m e l a n o p s i s lanzae, melanopsis euristoma, melanopsis kispatici and melanopsis pilari. »i»i∆ & milojevi∆ (1977) mention mammals found in bosnia and herzegovina, such a s mastodon angustidens, mastodon longirostris , d y notherium bavaricum and rinoceras sansaniensis , but it is now clear that some of these species are of a different neogene age. in the sinj basin (fig. 4), m a s t o d o n a n g u s t i d e n s sp. and a c e r a t h e r i u m sp.aff. i n c i s i v u m were determined (oluji∆, 1999). the upper miocene and pliocene deposits are characterized by marls, clays, siltstones, sandstones, conglomerates, limestones and coal beds. a molluscan association consists of congeria dalmatica , c o n g e r i a z o i s i, orygoceras dentaliforme , orygoceras cornucopi a e, h y d r o b i a sp., v a l v a t a sp., l y m n a e a sp., p i s i d i u m o v u l u m, melanopsis acanthica , melanopsis defensa, prososthenia tournoueri etc. some ostracods have been found, such as paralimnocythere rostrata , p o t a m o c y p r i s sp. and c a n d o n a sp.. the youngest pliocene to pleistocene newly determined molluscan species are odontohydrobia croatica and limnidia likana ( j u r i©i∆-pol©ak et al., 1997). the upper miocene and pliocene sediments are overlain by quaternary deposits. 4. the adriatic region in a region of the adriatic, as a part of the mediterranean, marine deposition was almost continuous from the paleogene into the neogene, although transgressive contacts have been registered at some localities. sediments of neogene age are almost of marine origin and the occurence of fresh-water sediments which include endemic species, such as on pag island (kochansky-devidé & sli©kovi∆, 1978), are very rare. the unconformities between sediments observed in several places belong to different stages, and are consequences of emergence due to local tectonics (turk, 1971; jenko & bistri»i∆, 1978; kalac & bajraktarevi∆, 1989; mileti∆ et al., 1995). the emergence was particularly long-lasting during the oligocene and early miocene, and resulted in the formation of a land corridor for mammalian migration from the dinarides to apulia (de giuli et al., 1987; j. radov»i∆, pers. comm.) 89paveliê: the south-western boundary of central paratethys generally, carbonates and fine-grained sediments prevail, and the thickness of the neogene deposits reaches eight hundreds metres (d. mileti∆, pers. comm.) which is much less than in the dinarides, north croatian basin and northern bosnia region, suggesting minor tectonic controls (fig. 3). the stratigraphy of the neogene deposits in the croatian part of the adriatic region is based on foraminiferal associations (jenko & bistri»i∆, 1978; kalac & bajraktarevi∆, 1989; mileti∆, 1994; mileti∆ & bajraktarevi∆, 1995; mileti∆ et al., 1995). a geological column of the koraljka-i well, which was located in the central adriatic, is presented in figs. 3 and 4. early miocene sedimentation is characterized by a dominance of carbonates, i.e. limestones and marls (fig. 3). a foraminiferal association consists of g l o b o quadrina dehiscens , globigerinoides trilobus , g o b igerinoides primordius and amphistegina lessonii. sedimentation was open marine. during the middle miocene marl sedimentation dominated, but limestones and sandy limestones were also deposited (fig. 3). in a foraminiferal association praeorbulina glomerosa , orbulina suturalis , a n o m a l i noides pompilioides, lenticulina vortex, s p i r o p l e c t i n e l la carinata , globoquadrina langhiana , orbulina uni versa, globorotalia praemenardii , globorotalia mayeri and globorotalia menardi prevail. this association suggests open marine deposition. in the late miocene, sedimentation was similar to that of the middle miocene. however, at the end of the late miocene evaporites were deposited in shallow lagoons. these deposits may be a result of a sea level fall due to the tectonic generated closure of the atlantic-mediterranean gateway. this event is known as the messinian salinity crisis (rögl & steininger, 1983). from the foraminiferal association, g l o b i g e r i n a n e p e n t h e s, lenticulina costata , uvigerina rutila , e l p h i dium crispum, elphidium complanatum, g l o b i g e r i n o ides extremus, globorotalia conomiozea , g l o b i g e r i n o ides bollii and ammonia beccarii dominate. marls, siltstones and sandstones characterize pliocene sedimentation. conglomerates are very rare and only occur sporadically. deposition was open marine. the cause of the sea level rise in the pliocene was a reopening of the atlantic-mediterranean gateway in the beginning of the pliocene (rögl & steininger, 1983). the most important pliocene foraminiferal species are globorotalia margaritae , uvigerina rutila , globorotalia puncticulata , anomalina helicina, g l o b o rotalia aemiliana , globorotalia crassaformis , globoro talia inflata and epistomina elegans. 5. discussion and conclusion the faunal characteristics of species which occur in sediments in the neogene fresh-water basins within the dinarides is almost endemic and can not be correlated with a marine fauna in the adriatic region. however, they show many similarities to endemic species found in deposits of the north croatian basin and northern bosnia region, i.e. central paratethys. the most frequent endemic species which occur both in the north croatian basin and northern bosnia region, belong to the molluscan genera congeria , unio, lymnaea, pisidi u m, m e l a n o p s i s, p l a n o r b i s , valvata and clivunella , and the ostracod genus candona . sedimentation in the north croatian basin and northern bosnia region, and in the dinaridic freshwater basins also show similarities. frequent changes of different types of sediments, including siliciclastics, coarse-grained deposits, coal-bearing beds, pyroclastics, emersions as well as mammalian occurrences are characteristic of both areas. the thickness of sediments in the dinaridic fresh-water basins is also more comparable to the north croatian basin and northern bosnia region than to the adriatic region. the strong tectonic control on sedimentation is also similar. similarities between the north croatian basin and northern bosnia region with dinaridic neogene basins suggest that these small basins show many faunal and depositional characteristics of central paratethys, and may be considered as a part of this realm. this means that the south-western boundary of the central paratethys may be constructed within the high karst belt, the mountain chain which separated the mediterranean from central paratethys (fig. 4), similar to ani∆’s (1951-1953) idea. in this sense, the boundary located in the northern bosnia and central croatia represents only the south-western shoreline of the sea or large lake which occupied the largest part of the central paratethys (fig. 4). acknowledgements the review of the manuscript by z. bajraktarevi∆, i. dragi»evi∆, k. ©iki∆, d. vrsaljko, m. m i k n i ∆ and j. buli∆ is gratefully acknowledged. i am indebted to r. avani∆, d. mileti∆ and i. sli©k o v i ∆ for providing helpful suggestions. this paper profited from journal reviewers f.f. s t e i n i n g e r (frankfurt), z. juri©i∆-pol©ak (zagreb) and j. radov»i∆ (zagreb). 6. references aljinovi∆, b., prelogovi∆, e. & skoko, d. (1987): novi podaci o dubinskoj geoloπkoj grai i seizmotektonski aktivnim zonama u jugoslaviji.geol. vjesnik, 40, 255-263. ani∆, d. (1951-1953): starost naslaga sa smeim ugljenom u bosni, hercegovini i dalmaciji.geol. vjesnik, 5-7, 73110. bahun, s. (1974): tektogeneza velebita i postanak jelarnaslaga.geol. vjesnik, 27, 35-51. 90 geologia croatica 55/1 berggren, w.a., kent, d.v., swisher, c.c. iii & aubry, m.-p. (1995): a revised cenozoic geochronology and chronostratigraphy.in: b e r g g r e n, w.a., kent, d.v., aubry, m.-p. & hardenbol, j. (eds.): geochronology, time scales and global stratigraphic correlations. spec. publ. soc. econ. pal. min., 54, 129212. bla©kovi∆, i. (1991): raspored uzduænih, reversnih i normalnih rasjeda i konstrukcija oblika i dubina ploha podvlaëenja.geol. vjesnik, 44, 247-256. bla©kovi∆, i. (1998): the two stages of structural formation of the coastal belt of the external dinarides.geol. croatica, 51/1, 75-89. bla©kovi∆, i. (1999): tectonics of part of the vinodol valley within the model of the continental crust subduction.geol. croatica, 52/2, 153-189. »i»i∆, s. & milojevi∆, r. (1977): terestriëno-limniëke naslage tercijara u bosni i hercegovini.in: »i»i∆, s. & pami∆, j. (eds.): geologija bosne i hercegovine. knjiga iii. kenozojske periode. geoinæenjering, sarajevo, 67106. de giuli, c., masini, f. & valleri, g. (1987): paleogeographic evolution of the adriatic area since oligocene to pleistocene.riv. it. paleont. strat., 93, 109-126, milano. dragi»evi∆, i. (2001): poslijeplatformni razvitak na dinarskoj karbonatnoj platformi.in: dragi»evi∆, i. & veli∆, i. (eds.): 1. znanstveni skup “karbonatna platforma ili karbonatne platforme dinarida”, knjiga saæ., rgnf, pmf, inst. za geol. istraæ & hgd, 89-90, zagreb. dragi»evi∆, i., prelogovi∆, e., kuk, v. & buljan, r. (1999): recent tectonic activity in the imotsko polje area.geol. croatica, 52/2, 191-196. gulyás, s. (2001): the paleogeography of lake pannon during deposition of the congeria rhomboidea beds.geol. croatica, 54/1, 15-26. hámor, g. & szentgyörgyi, k. (1981): outlines of geological structure and evolution of the miocene.excursion guide of molasse formations in hungary. hung. geol. inst. publ., 42-55, budapest. herak, m. (1986): a new concept of geotectonics of the dinarides.acta geol., 16/1, 1-42, zagreb. herak, m. (1991): dinaridi. mobilistiëki osvrt na genezu i strukturu.acta geol., 21/2, 35-117, zagreb. herak, m. (1999): tectonic interrelation of the dinarides and the southern alps.geol. croatica, 52/1, 83-98. herak, m. & tomi∆, v. (1995): continental subduction tectonics in the high karst dinarides of western croatia.geol. croatica, 48/2, 161-166. horváth, f. (1995): phases of compression during the evolution of the pannonian basin and its bearing on hydrocarbon exploration.mar. petrol. geol., 12, 837844. horvath, f. & royden, l.h. (1981): mechanism for the formation of the intra-carpathian basins: a rewiev.earth sci. rev., 3-4, 307-316. haq, b.u., hardenbol, j. & vail, p.r. (1987): chronology of fluctuating sea levels since the triassic (250 myr ago to present).science, 235, 1156-1167. jenko, k. & bistri»i∆, a. (1978): doprinos poznavanju biostratigrafskih odnosa mlaeg paleogena, neogena i kvartara dugootoëkog bazena.9. kongr. geol. jugosl., zbornik radova, 25-39, sarajevo. jovanovi∆, r., moji»evi∆, m., toki∆, s. & roki∆, lj. (1978): osnovna geoloπka karta sfrj 1:100.000, tumaë za list sarajevo, k34-1 (basic geological map of sfrj 1:100.000, explanatory notes for the sarajevo sheet).zav. za inæ. geol. i hidrogeol. gra. fakult., sarajevo, inst. za geol. istraæ., sarajevo, sav. geol. zavod, beograd, 52 p. juri©i∆-pol©ak, z. (1984): novi fosarulusi u slatkovodnom neogenu dalmacije (juæna hrvatska).rad jugosl. akad. znan. umjetn., 411, 197-208, zagreb. juri©i∆-pol©ak, z., krizmani∆, k. & hajek-tadesse, v. (1993): freshwater miocene of krbavsko polje in lika (croatia).geol. croatica, 46/2, 213-228. juri©i∆-pol©ak, z., saka», k. & poje, m. (1997): new pliopleistocene gastropods from lika, croatia.nat. croatica, 6, 91-111, zagreb. juri©i∆-pol©ak, z. & sli©kovi∆, t. (1988): slatkovodni gastropodi neogenskih naslaga jugozapadne bosne.zbor. ref. nauë. skupa “minerali, stijene, izumrli i æivi svijet bih”, 167-174, zem. muz. bos. herceg., sarajevo. kalac, k. & bajraktarevi∆, z. (1989): biostratigrafska istraæivanja naslaga pliocena i pleistocena podmorja sjevernog jadrana.geol. vjesnik, 42, 33-48. kochansky-devidé, v. (1976): o slatkovodnim mekuπcima srednjeg miocena hrvatske, bosne i hercegovine.8. jugosl. geol. kong., 2, 125-130, ljubljana. kochansky-devidé, v. (1979): srednjomiocenske kongerijske naslage poæeπke gore.geol. vjesnik, 31, 69-72. kochansky-devidé, v. & sli©kovi∆, t. ( 1 9 7 8 ) : miocenske kongerije hrvatske, bosne i hercegovine.palaeont. jugosl., 19, 1-98, zagreb. ková», m. & hudá»ková, n. (1997): changes of paleoenvironment as a result of interaction of tectonic events with sea level changes in the northeastern margin of vienna basin.zbl. geol. paläont. teil i, 5/6, 457-469, stuttgart. ková», m., nagymarosy, a., holcová, k., hudá»kova, n. & zlinská, a. (2001): p a l e o g e o g r a p h y , paleoecology, and eustacy: miocene 3rd order cycles of relative sea-level changes in the western carpathian north pannonian basins.acta geol. hung., 44, 1-45. kova», m., nagymarosy, a., oszczypko, n., csontos, l., slaczka, a., marunteanu, m., matenco, l. & márton, e. (1998): palinspastic reconstruction of the carpathian-pannonian region during the miocene.in: r a k u s, m. (ed.): geodynamic development of the western carpathians. mineralia slov. monograph., 189-217, bratislava. kuk, v., prelogovi∆, e. & dragi»evi∆, i. (2000): seismotectonically active zones in the dinarides.geol. croatica, 53/2, 295-303. 91paveliê: the south-western boundary of central paratethys laskarev, v. (1924): sur les equivalents du sarmatien superieur en serbie.in: vujevi∆, p. (ed.): receuil de traveaux offert á m. jovan cvijic par ses amis et collaborateurs. dræ. πtamp., 73-85, beograd. lu»i∆, d., safti∆, b., krizmani∆, k., prelogovi∆, e., britvi∆, v., mesi∆, i. & tadej, j. (2001): the neogene evolution and hydrocarbon potential of the pannonian basin in croatia.mar. petrol. geol., 18, 133-147. magyar, i., geary, d.h. & müller, p. (1999): paleogeographic evolution of the late miocene lake pannon in central europe.palaeogeogr., palaeoclim., palaeoecol., 147, 151-167. marin»i∆, s., korolija, b., mamuæi∆, p., maga©, n., majcen, æ., brki∆, m. & ben»ek, –. (1977): osnovna geoloπka karta sfrj 1:100.000, tumaë za list omiπ, k33-22 (basic geological map of sfrj 1:100.000, explanatory notes for the omiπ sheet).inst. za geol. istraæ., zagreb, 51 p. marinescu, f. (1992): les bioprovinces de la paratéthys et leurs relations.paleontologia i evolució, 24-25, 445453, sabadell. mati»ec, d., vlahovi∆, i., fu»ek, l., o©tri∆, n. & veli∆, i. (1997): stratigraphy and tectonic relationships along the senj-ogulin profile (velika kapela mt., croatia).geol. croatica, 50/2, 261-268. mati»ec, d., vlahovi∆, i., ti©ljar, j. & veli∆, i. (2001): sinsedimentacijska tektonika na jadranskoj karbonatnoj platformi.in: dragi»evi∆, i. & veli∆, i. (eds.): 1. znanstveni skup. karbonatna platforma ili karbonatne platforme dinarida.knjiga saæ., rgnf, pmf, inst. za geol. istraæ & hgd, 46-50, zagreb. mileti∆, d. (1994): foraminifere neogena istraænih buπotina u podmorju srednjeg jadrana.unpubl. m.sc. thesis, university of zagreb, 62 p. mileti∆, d. & barbi∆, z., slavkovi∆, r. & hernitz-ku»enjak, m. (1995): rezultati biostratigrafskih i petrografskih analiza sedimenata buπotine ines-1 (sjeverni jadran, hrvatska).in: vlahovi∆, i., veli∆, i. & ©parica, m. (eds.): 1. hrvatski geoloπki kongres. zbornik radova, 2, 383-386, inst. za geol. istraæ. & hrv. geol. druπ., zagreb. mileti∆, d. & bajraktarevi∆, z. (1995): biostratigrafska korelacija neogenskih sedimenata jadrana u buπotinama koraljka-1, ksenija-1 i ksenija-3.in: vlahovi∆, i., veli∆, i. & ©parica, m. (eds): 1. hrvatski geoloπki kongres. zbornik radova, 2, 379-382, inst. za geol. istraæ. & hrv. geol. druπ., zagreb. oluji∆, j. (1999): o razvojnim nizovima nekoliko melanopsida i prozostenida iz sarmatskih naslaga okolice sinja (dalmacija, hrvatska) (über die ahnenreihen einiger melanopsiden und prosostheniden aus melanopsis lanzae schichten der sinjaner neogenformation aus der sarmatischen stufe (sinj, dalmatien, croatien)).in: pol©akjuri©i∆, z. (ed.). hrvatski prirodoslovni muzej, zagreb, provincijalat franjevaëke provincije presvetog otkupiteja, sinj, 135 p. pami∆, j., belak, m. & slovenec, d. (1992/1993): donjomiocenski trahiandeziti (πoπoniti) krndije u slavoniji (sjeverna hrvatska).rad hazu, 463, 27-47, zagreb. pami∆, j., gu©i∆, i. & jelaska, v. (1998): geodynamic evolution of the central dinarides.tectonophysics, 297, 251-268. pami∆, j., pami∆, o., oluji∆, j., milojevi∆, d. veljkovi∆, d. & kapeler, i. (1978): osnovna geoloπka karta sfrj 1:100.000, tumaë za list vareπ, l34-133 (basic geological map of sfrj 1:100.000, explanatory notes for the vareπ sheet).inst. za geol. istraæ. sarajevo (1970), sav. geol. zavod beograd, 68 p. pape©, j. (1972): osnovna geoloπka karta sfrj 1:100.000, list livno k33-11 (basic geological map of sfrj 1:100.000, livno sheet).inst. za geol. istraæ. sarajevo, sav. geol. zavod beograd. pape©, j. (1975): osnovna geoloπka karta sfrj 1:100.000, tumaë za list livno, k33-11 (basic geological map of sfrj 1:100.000, explanatory notes for the livno sheet).inst. za geol. istraæ., sarajevo (1967), sav. geol. zavod beograd, 64 p. pape©, j. (1985): geologija jugozapadne bosne.geol. glasnik, pos. izd., 9, 197 p., geoinæ., sarajevo, inst. za geol., sarajevo. p a v e l i ∆, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.basin research, 13, 359-376. paveli∆, d., avani∆, r., bakra», k. & vrsaljko, d. (2001): ea r l y mi o c e n e braided river and lacustrine sedimentation in the ka l n i k mo u n t a i n area ( pa n n o n i a n ba s i n sy s t e m, nw cr o a t i a).geol. carpathica, 52, 375386. p a v e l i ∆, d., mikni∆, m. & sarkoti∆ ©lat, m. (1998): early to middle miocene facies succession in lacustrine and marine environments on the southwestern margin of the pannonian basin system.geol. carpathica, 49, 433-443. p a v e l i ∆, d. & kova»i∆, m. (1999): lower miocene alluvial deposits of the poæeπka mt. (pannonian basin, northern croatia): cycles, megacycles and tectonic implications.geol. croatica, 52/1, 67-76. pol©ak, a., ©parica, m., crnko, j. & juri©a, m. (1978): osnovna geoloπka karta sfrj 1:100.000, tumaë za list bihaê, l33-116 (basic geological map of sfrj 1:100.000, explanatory notes for the bihaê sheet).inst. za geol. istraæ., zagreb, 52 p. radov»i∆, j., maji∆, d. & juri©i∆-pol©ak, z. (1998): miocenski praslonovi i nosorozi iz moslavaëkog gorja.zbornik moslavine, 4, 5-11, muzej moslavine, kutina. rai∆, v., pape©, j., sikirica, v. & maga©, n. (1984): osnovna geoloπka karta sfrj 1:100.000, tumaë za list sinj, k33-10 (basic geological map of sfrj 1:100.000, explanatory notes for the bihaê sheet).geoinæ., inst. za geol. sarajevo, geol. zav. zagreb (1982), sav. geol. zavod beograd, 52 p. rögl, f. (1996): stratigraphic correlation of the paratethys oligocene and miocene.mitt. ges. bergbaustud. österr., 41, 65-73. rögl, f. (1998): paleogeographic considerations for mediterranean and paratethys seaways (oligocene to miocene).ann. naturhist. mus. wien, 99a, 279-310, wien. 92 geologia croatica 55/1 rögl, f. (1999): mediterranean and paratethys. facts and hypotheses of an oligocene to miocene paleogeography (short overview).geol. carpathica, 50, 339-349. rögl, f. & steininger, f.-f. (1983): vom zerfall der tethys zu mediterran und paratethys. die neogene palaeogeographie und palinspastik des zirkum-mediterranen raumes.ann. naturhist. mus. wien, 85, 135-163, wien. rögl, f. & steininger, f.-f. (1984). neogene paratethys, mediterranean and indo-pacific seaways.in: brenchley, p. (ed.): fossils and climate. 171-200, j. wiley & sons, london. royden, l.h. (1988): late cenozoic tectonics of the pannonian basin system.in: royden, l.h. & horváth, f. (eds.): the pannonian basin. a study in basin evolution. am. assoc. petrol. geol. mem., 45, 27-48. sene©, j. (1979): correlation du neogene de la tethys et de la paratethys base de la reconstitution de la geodynamique de la region de la mediterranee.geol. zborn. geol. carpathica, 30, 309-319. soka», a. (1980): miocenski ostrakodi sinjskog polja.geol. vjesnik, 31, 95-99. sokli∆, i. (1957): kenozoik bosne i hercegovine.2. kongres geologa sfrj, 64-72, sarajevo. steininger, f.f., rögl, f., hochuli, p. & müller, c. (1989): lignite deposition and marine cycles. the austrian tertiary lignite deposits a case history.aus den sitz. österr. akad. wiss. mathem.-naturw. kl., abt. i, bd., 5-10 heft, springer-verlag, wien, new york, 308332. steininger, f.f., müller, c. & rögl, f. (1988): correlation of central paratethys, eastern paratethys, and mediterranean neogene stages.in: royden, l.h. & horvath, f. (eds.): the pannonian basin. a study in basin evolution. am. assoc. petrol. geol. mem., 45, 7987. steininger, f. & rögl, f. (1979): the paratethys history a contribution towards the neogene dynamics of the alpine orogene (an abstract).ann. géol. pays hellén., tome hors serie, fasc. iii, 1153-1165, athens. steininger, f. & rögl, f. (1984): paleogeography and palinspastic reconstruction of the neogene of the mediterranean and paratethys.in: dixon, j.e & robertson, a.h.f. (eds.): the geological evolution of the eastern mediterranean. geol. society, blackwell, oxford, 659-668. ©∆avni»ar, s., krkalo, e., ©∆avni»ar, b., halle, r. & tiblja©, d. (1983): naslage s analcimom u poljanskoj.rad jugosl. akad. znan. umjetn., 404, 137-169, zagreb. ©u©njara, a. & saka», k. (1988): miocenski slatkovodni sedimenti podruëja sinja u srednjoj dalmaciji.geol. vjesnik, 41, 51-74. ©u©njara, a. & ©∆avni»ar, b. (1974): tufovi u neogenskim naslagama srednje dalmacije (juæna hrvatska).geol. vjesnik, 27, 239-253. tari, g., horváth, f. & rumpler, j. (1992): styles of extension in the pannonian basin.tectonophysics, 208, 203-219. tari, v. & pami∆, j. (1998): geodynamic evolution of the northern dinarides and the southern part of the pannonian basin.tectonophysics, 297, 269-281. turk, m. (1971): graa tercijarnog bazena u sjeveroistoënom dijelu jadranskog mora.nafta, 22, 275-282, zagreb. veli∆, j., ti©ljar, j., dragi»evi∆, i. & bla©kovi∆, i. (2000): shoreline cross-bedded biocalcarenites (middle miocene) in the podvrπko-©njegaviê area, mt. psunj, and their petroleum significance (poæega subdepression eastern croatia).geol. croatica, 53/2, 281-293. æivanovi∆, m. & milojevi∆, r. (1971): osnovna geoloπka karta sfrj 1:100.000, list zenica, l33-144 (basic geological map of sfrj 1:100.000, zenica sheet).inst. za geol. istraæ. sarajevo, sav. geol. zavod beograd, . æivanovi∆, m., sofilj, j. & milojevi∆, r. (1971): osnovna geoloπka karta sfrj 1:100.000, tumaë za list zenica, l33-144 (basic geological map of sfrj 1:100.000, explanatory notes for the zenica sheet).inst. za geol. istraæ. sarajevo (1967), sav. geol. zavod beograd, 60 p. æagar-saka», a. & saka», k. (1984): nalaziπta unionacejske faune neogenskih (miocenskih) naslaga dalmacije (juæna hrvatska).rad jugosl. akad. znan. umjetn., 411, 209-230, zagreb. manuscript received february 21, 2002. revised manuscript accepted may 20, 2002. velic et al.indd 1. introduction during the lengthy existence of the adriatic carbonate platform (from late lias to the late cretaceous – see discussion in vlahović et al., 2002) some periods were characterised by the significant variability of depositional environments, i.e. apparent facies differentiation as reflected in the specific rock record. these episodes are very important for the analysis of extrinsic and intrinsic influences on platform evolution, but also for the interpretation of its physiography. one of the palaeogeographic variability and depositional environments of the upper jurassic carbonate rocks of velika kapela mt. (gorski kotar area, adriatic carbonate platform, croatia) ivo velić1, josip tišljar2, igor vlahović1, josipa velić2, georg koch1 and dubravko matičec1 most significant such events took place during the late jurassic. this stratigraphic level, characterised by the occurrence of so-called “lemeš deposits” (furlani, 1910) and similar limestones with cherts and ammonites, was claimed as one of the most important evidences of the existence of supposed two mesozoic platforms which are today incorporated into the dinarides (herak, 1986, 1989), and therefore should be carefully examined. it is important to emphasize that since the isolation of the adriatic carbonate platform, i.e. its establishment, which occurred in the middle to late lias (see discussion in vlahović et al., 2002), the studied period is the first regionally recognised major palaeogeographic event. dynamic changes in the wider surroundings caused increased tectonic activity within geologia croatica 55/2 121–138 15 figs. 1 pl. zagreb 2002 key words: palaeogeography, synsedimentary tectonics, facies variability, platform carbonates, intraplatform trough, limestones with chert, hydrozoan–coral reefs and peri-reefal area, kimmeridgian, velika kapela mt., croatia. 1 institute of geology zagreb, sachsova 2, p.o.box 268, hr-10000 zagreb, croatia; e-mail: ivelic@igi.hr. 2 university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, hr-10000 zagreb, croatia. abstract synsedimentary tectonics caused significant differentiation of sedimentary environments of the adriatic carbonate platform during the kimmeridgian. the most important changes have been recorded in w and central croatia: along the nw part in present day w istria there was an emergence with bauxite deposits, while along the ne margin of the platform, in the karlovac area, a former emerged area was submerged. penecontemporaneously between these areas, in the wider area of velika kapela mt., a shallow intraplatform trough was formed, characterised by deposition of dark mudstones with nodules and thin layers of cherts and thin interbeds of tuffs in the upper part of the succession. occurrences of planktonic foraminifera, radiolarians, calcisphaeres and rare ammonites indicate the sporadic influence of the open sea. along the margins of the trough, peri-reefal environments were established, with flourishing developments of different reefbuilding organisms – hydrozoans, stromatoporoids, corals and bryozoans. reefs were continuously destroyed, and in this way derived material was reworked and transported towards the trough slopes. an enormous quantity of this material caused progradation towards the deeper central part of the area, which was gradually infilled and narrowed. in the final phase, the trough was completely infilled, and perireefal environments gradually disappeared, since they were covered by ooid bars, culminating in the establishment of shallow environments over the entire area. a similar situation was recorded in another contemporaneous, also tectonically formed environment – the lemeš trough, stretching from the vicinity of bihać in nw bosnia towards the south into croatia, into e lika and n dalmatia. this trough had direct communication with the open tethys realm, and thin-bedded and platy limestones with chert and pelagic organisms, including common ammonites, were deposited within it. the lemeš trough was also surrounded by coral–hydrozoan reefs, and it was infilled by the same depositional processes as the neighbouring trough in the area of velika kapela mt., and finally covered by shallow-water deposits. although both troughs were probably formed by the same tectonic act, and had approximately the same duration – during the kimmeridgian and early tithonian – they differ according to their palaeogeographic and facies characteristics. the trough investigated in the velika kapela mt. was isolated, surrounded by shallow-marine platform environments, and had only temporary, indirect contact with the open sea. the lemeš trough had a continuous connection with the open sea, as indicated by the relatively rich assemblages of pelagic organisms, especially ammonites, and is characterised by abundant cherts. however, both troughs are characterised by similar depositional sequences: both are underlain and overlain by shallow-water carbonate deposits, and they represent a consequence of a specific depositional event caused by tectonic deformation (formation of pull-apart basins) within the inner part of the adriatic carbonate platform. 122 geologia croatica 55/2 123velić et al.: palaeogeographic variability and depositional environments of the upper jurassic... the platform area. however, younger tectonics obscured its consequences, and therefore made interpretation of its origin and importance very difficult (tišljar et al., 1994; velić et al., 1994, 2002; bucković, 1995; matičec et al., 2001; vlahović et al., 2001). 2. succession of the kimmeridgian deposits in e gorski kotar (wider area of the velika kapela mt.) the area of gorski kotar is especially interesting for the interpretation of general palaeogeographic events in the area of the adriatic carbonate platform during the late jurassic, since during this period it was characterised by significant facies variability. different facies were investigated in several detailed geological columns and by geological mapping of the wider area of velika kapela mt. (fig. 1). the study area is very disturbed by younger, especially tertiary and quaternary tectonics, and it is not easy to find undisturbed successions of malm carbonate deposits. considering the main goal of the study, i.e. investigation of kimmeridgian deposits (so-called limestones with cherts) and facies underlying and overlying them, the study area encompassed the region from the vicinity of mrkopalj se, towards brinje. among several columns and profiles the most complete was determined in the area of breze (fig. 2), but relationships in the mrkopalj (fig. 3), tuk (fig. 4), matić poljana–sunger (fig. 5) and mala javornica (fig. 6) columns will also be discussed. 2.1. lithofacies a – lagoonal limestones limestones with cherts are underlain in the study area by an approximately 35 m thick succession of dark grey, in some places black, thick-bedded to massive (50–80, commonly 150–200 cm thick beds) micritic limestones with oncoid and nubecularians (fig. 2, lithofacies a). these are composed of homogenous mudstones, bioclastic wackestones with benthic foraminifera and molluscan bioclasts, peloid wackestones and bioclastic–peloid wackestone/packstones, oncoid–skeletal–peloid wackestones to grainstones and nubecularian wackestones with echinoid bioclasts and calcisphaerids. the following fossil assemblage of shallow marine benthos has been determined by micropalaeontological analysis (in their order of occurrence): praekurnubia crusei redmond, salpingoporella sellii (crescenti), nautiloculina oolithica (mohler), pseudocyclammina sp., cladocoropsis mirabilis felix, everticyclammina sp., kurnubia palastiniensis henson, trocholina sp., redmondoides lugeoni (septfontaine), pfenderella arabica redmond, pseudocyclammina lituus (yokoyama), salpingoporella grudii (radoičić), griphoporella minima nikler & sokač, accompanied by indeterminable lituolids and valvulinids, molluscan, hydrozoan and echinoderm debris, ostracods, nubecularids and thaumatoporellas. occurrences of saccocoma sp. indicate sporadic pelagic influences. the aforementioned assemblage indicates a latest oxfordian to earliest kimmeridgian age, i.e. these deposits correspond to the oxfordian–kimmeridgian transition level. biostratigraphically they belong to the salpingoporella fig. 1 location map of the study area with the distribution of upper jurassic deposits of different palaeoenvironments. legend: 1 – shallow-water oxfordian (lithofacies a in this paper) and tithonian limestones; 2 – limestones with cherts (lithofacies b1 and b2 in this paper); 3 – reefal–perireefal deposits (lithofacies c in this paper); 4 – position of the studied geological columns: mk – mrkopalj; tuk – tuk; mps – matić poljana–sunger; br – breze; mj – mala javornica. 122 geologia croatica 55/2 123velić et al.: palaeogeographic variability and depositional environments of the upper jurassic... fig. 2 the geological column at breze and legend for all geological columns. 1 2 k im m e r id g ia n t it h o n ia n 124 geologia croatica 55/2 125velić et al.: palaeogeographic variability and depositional environments of the upper jurassic... fig. 3 the geological column at mrkopalj. 1 k im m e r id g ia n t it h o n ia n 2 124 geologia croatica 55/2 125velić et al.: palaeogeographic variability and depositional environments of the upper jurassic... fig. 4 the geological column at tuk. k im m e r id g ia n t it h o n ia n 1 2 126 geologia croatica 55/2 127velić et al.: palaeogeographic variability and depositional environments of the upper jurassic... sellii assemblage zone defined by velić & sokač (1974, 1978) and velić (1977). these limestones were deposited in low energy subtidal areas of the lagoon, and its flanks probably formed gently inclined inner platform carbonate ramps. carbonate mud, peloids, algal oncoids, ostracods, nubecularids, dasycladaceans and benthic foraminifera represent the autochthonous material, while echinoid and mollusc debris were probably introduced from neighbouring shallows. 2.2. lithofacies b – limestones with cherts limestones with cherts (lithofacies b in figs. 2–6) occurs in all the studied columns, but with variable thickness. the complete succession was investigated in the breze column, while in the mrkopalj and tuk columns the lower part is tectonically reduced. in the matić poljana (sunger) and mala javornica columns the lower part of this unit is also tectonically reduced, and the upper part is eroded. within the limestones with cherts, two units can be separated (b1 and b2), both characterised by wellbedded micritic limestones with chert nodules, but the upper (younger) unit also comprises clinoforms composed of peri-reefal debris. well-bedded micritic limestones with chert nodules (lithofacies b1) are, in the central part of the breze column, 78 m thick (fig. 2), 23 m in the mrkopalj column without a lower contact (fig. 3), 43 m in the tuk column without lower contact (fig. 4), and 64 m thick in the mala javornica column without lower and upper contacts (fig. 6). they are composed of the alternation of frequently recrystallized and silicified oncoid–peloid–skeletal wackestones (rarely skeletal–peloid packstone to grainstones), and mudstones to wackestones with pelagic fauna (fig. 7), interlayered with cryptocrystalline cherts with radiolarians (fig. 8), macrocrystalline late-diagenetic dolomites and intensely weathered and altered crystalo-vitroclastic tuffs to tuffitic mudstones. besides well-bedded deposits (fig. 9) in some places, thin-bedded varieties have been found (e.g. in the mala javornica profile – fig. 10), including rare ammonites (fig. 11). within peloid–skeletal wackestones, and especially within mudstones, laminae, grains and globules of organic matter (om) occur. according to the in situ3 appearance, the om of lithofacies b1 may be characterised as bituminite, partly as lamalginite, especially within laminated mudstones. however, they exhibit weak fluorescence intensity, and in some segments they do not fluoresce at all. this may be explained, at least partly, as a consequence of secondary oxidation of om due to tectonically fissured deposits and their exposure to weathering. this is well documented by the fig. 5 the geological column at matić poljana–sunger. 3 analysis of the polished surface of samples in incident blue light as well as thin sections in white transmitted light and incident blue light. 2 k im m e r id g ia n t it h o n ia n 126 geologia croatica 55/2 127velić et al.: palaeogeographic variability and depositional environments of the upper jurassic... recrystallized nature of the limestones, which increases their permeability, and by the often numerous narrow cracks infilled with secondary calcite. even within the laminated parts of the limestones, thin secondary calcite veins have been observed showing selective oxidation of om while penetrating into the interlaminar space. the palynological composition of om4 of lithofacies b1 shows varying amounts of marine (85–95%) and land (5–15%) derived palynodebris. the mean value of the ratio marine/terrestrial om is estimated at 9/1. marine derived palynodebris consists of heterogenous, spongy, clotted and granular (pl. 1, figs. 2, 3, 6) as well as homogenous (pl. 1, figs. 1, 3) varieties of amorphous organic matter (aom). rare framboidal pyrite inclusions have been observed within the heterogenous type of aom. according to the fluorescence and morphological features, four types of aom can be differentiated: (1) heterogenous, nonfluorescent, (2) heterogenous, dull orange fluorescence, and (3) relatively homogenous, non-fluorescent, (4) relatively homogenous, dull yellow-orange fluorescence. the first two types are plankton/bacterial derived, whereas the third and the fourth types are microbial mat derived. the quantity of these four types of aom varies from sample to sample; on average, the second type predominates. the third and the fourth types form up to 1/5 of the total aom most common within the finely laminated parts of mudstones. as already mentioned, secondary oxidation has left an obvious signature on the preservation state of the aom. this represents a limiting factor when estimating the true proportion of aom which might have been partially oxidised before and during final deposition, because non-fluorescent and weakly fluorescent aom may also be produced by biodegradation of planktonic or microbial mat om (tyson, 1995). it is also possible that the deposited aom was synsedimentary affected by flushing and erosion (resuspension). nevertheless, secondary oxidation of aom has to be taken into account, meaning that the unoxidised equivalents would reveal a higher fluorescence intensity, thus indicating at least a moderate degree of aom preservation. marine palynomorphs are regularly represented by varying, but low concentrations of moderately preserved prasinophycean phycomata (leiosphaeridia – pl. 1, fig. 2, tasmanites – pl. 1, fig. 3), always less than 1% of the overall palynodebris composition. moderately preserved proximate dinosporin cysts (escharisphaeridia – pl. 1, fig. 4) occur in very low concentrations. other types of dinosporin cysts, or parts thereof, have not been observed. the mean value of the ratio of prasinophyte phycomata/dinosporin cysts is estimated at 5/1. prasinophyte phycomata and dinosporin cysts exhibit moderate yellow fluorescence. land derived palynomorphs occur in very low concentrations, represented by degraded bissacate pollen and circumpolles pollen (corollina/classopollis – pl. 1, fig. 5). the spores are strongly degraded and they occur extremely rarely in only a few samples. land derived palynodebris consists mostly of brown to dark brown, weakly to moderately structured clasts of transculent phytoclasts of woody tissue (80–90%; pl. 1, fig. 6) and opâque phytoclasts (10–20%; pl. 1, fig. 2) of land plant origin. the mean value of the ratio of transculent phytoclasts/opâque phytoclasts is estimated at 6/1. both fractions occur as lath-shaped and angular to semiangular equidimensional clasts variable in size. their sorting and rounding is mostly weak, and in some samples weak to moderate. fig. 6 the geological column at mala javornica. 4 for palynological processing only hcl (10%) was used to dissolve the carbonates. no further treatment (dissolving of silicates in hf, heavy liquid separation, sieving, oxidation) has been attempted in order to analyze the organic matter as a whole and to avoid damaging and alteration of the preservation state of organic matter due to processing. analysis of om was performed both in transmitted white light and incident blue light. 1 k im m e r id g ia n t it h o n ia n 128 geologia croatica 55/2 129velić et al.: palaeogeographic variability and depositional environments of the upper jurassic... an alternation of well-bedded micritic limestones with chert nodules and clinoforms composed of reefal–perireefal detritus (lithofacies b2) has been found in the upper parts of the breze (thickness 65 m – fig. 2), mrkopalj (approximately 95 m thick – fig. 3) and tuk columns (approximately 100 m – fig. 4). micritic limestones with chert nodules, as autochthonous deposits of the intraplatform trough, correspond to the previously described deposits of lithofacies b1. these deposits alternate with thinner or thicker, in some places clinoform interbeds of bioclastic–intraclastic limestones (fig. 12), which are mostly grainstones in their lower part, gradually passing upwards into bioclastic rudstones with a grainstone matrix. however, in some localities (e.g. mrkopalj, tuk, matić poljana–sunger columns) mud-supported lithotypes – packstones and floatstones, are predominant. interbeds of dark grey to black mudstones and wackestones also contain irregular concentrations of om, both as granules in the matrix and impregnations within micrite and along stylolytic sutures. both the in situ appearance and palynological composition of the om of lithofacies b2 corresponds to lithofacies b1, differing in a lower mean value of the marine/terrestrial om ratio (4/1) as well as in the lower mean value of the transculent phytoclasts/opâque phytoclasts ratio (3/1) and their moderate sorting and rounding. the fossil assemblage found within the limestones with cherts, although relatively moderate in respect to the underlying and overlying deposits, is quite interesting for facies interpretation. two groups of fossils can be separated: autochthonous (pelagic and slope organisms) and allochthonous (peri-reefal and platform benthos). the pelagic assemblage is composed mostly of microfossils, e.g. globochaete alpina lombard, saccocoma sp. (fig. 13), spirillina sp., calcisphaers, calcitized radiolarians, sponge spicules, pelagic bivalves and echinoderms. among the macrofossils only rare ammonites have been found, which were indeterminable at species level; however, nikler (1965) has determined the genus perisphinctes and species p. (virgatosphinctes) denseplicatus (waagen) in the area of breze and tuk. within the microfossil assemblage characteristic for slope environments protopeneroplis striata weynschenk, mohlerina basiliensis (mohler) and lenticulina sp. have been found. within successions situated in the proximal parts of the intraplatform trough, i.e. the matić poljana–sunger and mala javornica columns (figs. 5 and 6), besides the autochthonous deposits, numerous redeposited platform fig. 7 a photomicrograph of fine-grained peloidal–skeletal wackestone with rare radiolarians; lithofacies b1, tuk column, 31x. fig. 8 a photomicrograph of the irregular contact of a diagenetic chert nodule (light grey) and peloidal–bioclastic wackestone/ packstone; lithofacies b1, mala javornica column, 6.5x. 128 geologia croatica 55/2 129velić et al.: palaeogeographic variability and depositional environments of the upper jurassic... benthic forms have been found, e.g. parurgonina caelinensis cuvillier, foury & pignatti-morano, pseudocyclammina lituus (yokoyama), charentia evoluta (gorbatchik) and redmondoides lugeoni (septfontaine). clinoforms occurring within the upper part of the limestones with cherts comprise debris of reef-building organisms and pseudocyclammina lituus (yokoyama), campbelliella striata (carozzi), charentia evoluta (gorbatchik), everticyclammina sp., coscinophragma sp., valvulinids and lituolids. according to the primary facies distribution, palynomorphs and palynodebris of limestones with cherts can be differentiated into autochthonous (marine derived) and allochthonous (land derived) material. phycomata of planktonic prasinophyte algae show a more pelagic distribution pattern, and their abundance is environmentally controlled (tyson, 1995). they are most common in marine, organic-rich, finely laminated deposits that accumulate under conditions of lowered oxygenation (tyson, 1995; batten, 1996). phycomata are seldom volumetrically significant in such deposits compared to the total organic matter (tyson, 1995). their dominance (as a percentage) is more specifically related to other phytoplankoton. tappan (1980) has attributed prasinophycean algae as a “disaster species”, i.e. their abundance especially increases where the ecological conditions for the development of other phytoplankton communities are not suitable. according to tyson (1995), the abundance of phycomata in many organic-rich deposits is at least partly a consequence of reduced dinocyst or acritarch production in permanently stratified basins which does not reflect the original phytoplankton assemblage, i.e. the real phytoplankton community dynamics. therefore, the ratio of phycomata/dinocysts is an indicator of hydrographic stability and its value increases in the more pelagic facies of stratified basins. distal facies with low siliciclastic sediment accumulation are characterised by condensed sections and pelagic facies with the most organic-rich sediments which reveal thin and localized occurrences fig. 9 outcrops of typical well-bedded lithofacies b1 deposits in the mrkopalj column (hammer for scale). fig. 10 thin-bedded variety of the lithofacies b1 deposits in the mala javornica column (scale is 2 m long). fig. 11 scarce ammonite (perisphinctes sp.) from the lithofacies b1 deposits in the mala javornica column. fig. 12 a photomicrograph of fine-grained, relatively well-sorted bioclastic–intraclastic–peloidal packstone/grainstone; lithofacies b2, breze column, 10.5x. 130 geologia croatica 55/2 131velić et al.: palaeogeographic variability and depositional environments of the upper jurassic... of unusually high phycomata abundance (tyson, 1995). prasinophyte phycomata are also common in the lower parts of transgressive sequences and shallow water facies related to the maximum flooding surface (tyson, 1995). the dominance of prasinophyte algae has also been recorded from restricted (partly hypersaline, partly anoxic) lagoons and shallow water carbonate depositional sets. these occurrences probably also reflect the inhibition of dinosporin cyst production and a corresponding relative increase in prasynophytes (tyson, 1995). organic-rich, laminated deposits with relatively abundant prasinophycean phycomata have also been recorded from a shallow, restricted-marine, anoxic environment with increased salinity of the adriatic carbonate platform (jerinić et al., 1994). the palynofacies of marine organic-rich, laminated sediments is dominated by aom, most of it being derived from phytoplankton and bacteria (raynaud et al., 1989; tyson, 1995; batten, 1996). this type of aom is often associated with pyrite inclusions in depositional sets where iron is available. otherwise, the sulphur is incorporated into organic compounds (tissot & welte, 1984). the deposition of land derived palynodebris is hydrodynamically controlled according to their buoyancy features and depositional energy. according to gorin & steffen (1991) the size, sorting, rounding and preservation degree of phytoclasts as well as the ratio of marine/terrestrial organic matter are good indicators of proximal/distal relationships. in the distal direction on a carbonate shelf, the size of equidimensional opâque phytoclasts decreases, while sorting and rounding increases, the proportion of lathshaped opâque phytoclasts increases, the preservation of phytoclasts increases, and the ratio of marine/terrestrial om increases. on the basis of these considerations, the palynofacies of the limestones with cherts indicates that they were deposited in an oxygen-depleted, relatively shallow, restricted depositional setting (lagoon). these conditions enabled formation of a palynofacies dominated by algal/microbial derived aom with rare pyrite inclusions. this limited formation of pyrite was due to the low amount of iron which is consistent with the depositional sets of carbonate platforms. the composition of land derived organic clasts as well as their size, sorting and rounding suggests relatively short transport before final deposition and the relative proximity of the emerged part of the carbonate platform where the probably scanty and undiversified vegetation was established. variations in the ratio of marine/terrestrial om indicates sea-level fluctuation and/or synsedimentary tectonics with an upward regressive trend in the studied columns. most of the aforementioned fossils are characterised by wide stratigraphic spans, mostly from the dogger to the berriasian; exceptions include the species parurgonina caelinensis cuvillier, foury & pignatti-morano and campbelliella striata (carozzi). their occurrence within clinoforms of lithofacies b2 are very important, since their stratigraphic ranges accompanied by the defined age of the underlying deposits can help determine the age of the limestones with cherts. the stratigraphic range of p. caelinensis in the mediterranean region, as well as in the area of velika kapela mt. (velić & sokač, 1974, 1978, velić, 1977) is kimmeridgian–tithonian, while c. striata indicates a latest lower tithonian to upper tithonian age. considering the fact that the limestones with cherts are overlain by a thick sequence of tithonian peri-reefal limestones, their stratigraphic range should therefore be approximated to extend through most of the kimmeridgian and lower tithonian, i.e. to the end of the lower tithonian. limestones with cherts were deposited under oxygen-depleted conditions within the intraplatform trough. deposition of autochthonous, relatively organic-rich (mainly aom) mudstones and wackestones, was gradually more and more interrupted by inputs of both carbonate allochtonous material (fineand coarse-grained detritus) from reefs and ooid shoals surrounding the intraplatform trough, and a small amount of organic allochthonous material (mainly palynodebris of woody tissue) derived from the vegetation established on the emerged part of the carbonate platform. this was the consequence of progradation of peri-reefal and ooid deposits towards the inner part of the trough. differences recorded in the investigated columns concern the variable amounts of both inorganic and organic autochthonous and allochthonous material resulting from their different positions within the intraplatform trough, characterised by the complex morphology and bathymetry as well as uneven primary bioproduction and progradation of reefal detritus and ooids. 2.3. lihofacies c – reefal–perireefal limestones and late-diagenetic dolomites massive limestones composed predominantly of reefal detritus overlie the limestones with cherts. they were fig. 13 a photomicrograph of bioclastic–intraclastic–peloidal packstone with coarse bioclasts of molluscs and pelagic forms including saccocoma sp.; lithofacies b2, tuk column, 8.5x. 130 geologia croatica 55/2 131velić et al.: palaeogeographic variability and depositional environments of the upper jurassic... distinguished in the upper part of the breze, mrkopalj and tuk columns (figs. 2, 3 and 4, lithofacies c). their thickness could not be precisely determined because of their significant tectonic disturbance, i.e. possible duplication by faulting, very significant lateral variability caused by palaeomorphology, intense late-diagenetic dolomitization and dense vegetation. however, in the area of breze their thickness was estimated at 1000 m (šušnjar et al., 1970). limestones of this unit are composed of thick-bedded to massive mediumto coarse-grained bioclastic– lithoclastic grainstone–packstones and rudstone–floatstones with lenses, nodules and interbeds of cherts, and, especially along the fault zones, late-diagenetic dolomites. limestones are generally characterised by erosional lower bedding surfaces and either coarsening or fining-upward trends. grainstones are composed of well-sorted and wellrounded bioclasts of hydrozoans, stromatoporoids, echinoderms and molluscs, micritic, biomicritic, pelmicritic and pelsparitic intraclasts, and relatively high amounts of macrocrystalline and syntaxial calcite cements (fig. 14). algal oncoids, micritized benthic foraminiferal tests and ooids with radial structures are less frequent. grainstones commonly gradually change into packstones with different amounts of matrix composed either of micrite or finely crushed fossil detritus, which is in some places recrystallized into microsparite. rudstones differ from grainstones not only in their, by definition, larger amount of coarser grains – but also with their concurrent increase of stromatoporoid, coral and mollusc bioclasts and pelsparitic and intrasparitic intraclasts with respect to echinoderms which has been recorded. additionally, lithotypes with coarse allochems are characterised by lesser amounts of well-rounded grains. floatstones are characterised by the same coarse allochems, but instead of calcite cements intergranular spaces are filled by variable amounts of biopelmicritic matrix. chert lenses, nodules and interbeds are composed of cryptocrystalline to microcrystalline quartz aggregates with xenotypic crystal contacts and variable preservation, depending on the type of the substituted original allochem. silicification was selective, i.e. its intensity was variable on different grains. for example, the original shape of bivalve and gastropod bioclasts and ooids are commonly preserved, even after their complete silicification. some bioclasts (especially echinoderms), intraclasts and oncoids left as unsilicified relics within a microcrystalline or cryptocrystalline quartz mass, which is commonly contaminated by clay minerals and fine aggregates of sericite (or illite?), probably resulted from the alteration of volcanoclastic material. late-diagenetic dolomites are quite common, in some places even predominant, and they usually contain relics of undolomitised bioclastic limestones. they are characterised by microand macrocrystalline mosaic structure composed of hypidiotopic to idiotopic, rarely xenotopic dolomite crystals. intercrystal pores, dissolution cavities and tectonic fissures usually contain calcitic cement, and their superficial parts are commonly dedolomitized. the fossil assemblage found within the reefal–perireefal carbonates is very rich (fig. 15). former investigations of the wider area of velika kapela mt. resulted in the description of numerous reef-building organisms – corals, hydrozoans, stromatoporoids, bryozoans, gastropods, bivalves, echinoderms, brachiopods, etc. (e.g. poljak, 1936a, b, 1944; milan, 1969; nikler, 1969; turnšek, 1975; velić, 1977). those most frequently mentioned are some taxa from the sphaeractinidae family, e.g. ellipsactinia ellipsoidea steinmann, e. caprense canavari, e. polypora canavari, e. ramosa canavari, e. tyrhenica canavari, sphaeractinia steinmanni canavari, s. diceratina steinmann, gastropods of genus nerinea, e.g. n. defrancei posthuma zittel, n. zeuschneri peters, then ptygmatis bruntrutana (thurmann), cryptoplocus consobrinus zittel, etc. among the microfossils, typical latest upper jurassic forms of calcareous algae and benthic foraminifera have been determined, e.g. clypeina jurassica favre, campbelliella striata (carozzi), kurnubia palastiniensis henson, parurgonina caelinensis cuvillier, foury & pignatti-morano, etc. on the basis of the aforementioned fossil assemblage, results of previous investigations and relationships in the investigated area, it may be concluded that reefal–perireefal deposits were deposited within a stratigraphic range from the middle kimmeridgian to the end of the tithonian. there is no common opinion regarding the age and stratigraphic position of the reefal–perireefal deposits within the upper jurassic succession of the wider area. in slovenia, i.e. areas of trnovski gozd, notranjska and suha krajina, perireefal limestones are overlain by oolitic and clypeina limestones according to buser (1989), turnšek et al. (1981) and turnšek (1997), and therefore their stratigraphic range is estimated as oxfordian–kimmeridgian. howfig. 14 a photomicrograph of bioclastic–intraclastic–peloidal grainstone with coarse bioclasts; lithofacies c, breze column, 13x. 132 geologia croatica 55/2 133velić et al.: palaeogeographic variability and depositional environments of the upper jurassic... ever, nikler (1978) determined a tihonian age for the perireefal limestones of trnovski gozd mt., since at the velika ojstrovca locality he studied a complete succession from the middle lias to the tithonian: limestones with orbitopsellas are overlain by “spotty limestones” of the upper lias, then there was a lengthy hiatus until the transgressive kimmeridgian limestones with cherts, which are overlain by perireefal facies. this described succession completely corresponds to the penecontemporaneous deposits near the northern margin of the adriatic carbonate platform, studied by bukovac et al. (1974, 1984) in the vicinity of karlovac. “reefal deposits” (although they are usually referred to as “reefal limestones”, especially in the older literature, comprise a relatively small part of in situ reefs – most of the material is reworked) of the wider area of velika kapela mt. and vicinity of karlovac are of upper kimmeridgian to tithonian age, as determined by milan (1965, 1969), nikler (1965, 1969, 1978), bukovac et al. (1974, 1984), velić (1977), tišljar & velić (1991), velić et al. (1994), etc. in the areas with the most abundant jurassic coral– hydrozoan reefs and peri-reefal areas, i.e. the e–se part of the platform from central bosnia to southern montenegro, their stratigraphic position is determined only as upper jurassic in general (e.g. papeš, 1972, 1985; vujnović, 1980; mirković et al., 1977, 1979; mirković & vujisić, 1989). reefal–perireefal deposits originated in the shallow, high-energy part of the intraplatform trough, mostly as a result of the intense input and migration of bioclastic and inorganic detritus from reefs, and to a lesser extent, ooid shoals. shallowing of the depositional area was gradual, as a consequence of the progradation of bioclastic material (generally characterised by a coarsening-upward trend), of the forereef–reef facies belt and ooid shoals over autochthonous deposits of the intraplatform trough (velić et al., 1994; tišljar et al. 1994). this trend is recorded by a gradual vertical transition from lithofacies b1 to lithofacies b2 and finally to lithofacies c. described succession is typical for the area of the eastern gorski kotar (fig. 1). in the neighbouring areas of nw gorski kotar, nw lika and velebit, as well as in the velika kapela mt. and area ne of it, upper jurassic deposits are characterised by different, but exclusively shallow-marine facies, deposited within shallow lagoons, low-energy shallow subtidal to peritidal environments. these deposits are described in detail in other papers (velić & sokač, 1974, 1978; velić, 1977; tišljar & velić, 1993; tišljar et al., 1994), enabling reliable biostratigraphic correlation of these facially different successions of upper jurassic rocks. 3. geological events during the kimmeridgian on the adriatic carbonate platform during the oxfordian, the area of the adriatic carbonate platform was characterised by relatively uniform sedimentation. the southern and sw part of the platform, which is today mostly covered by the adriatic sea, was characterised by high-energy environments, resulting in deposition of carbonate sand bars mostly composed of ooids. the remainder of the platform, except for the ne margin which had been emergent since the late lias, was characterised by lagoonal environments. the beginning of the malmian was characterised by the gradual differentiation of environments, with the maximum in the kimmeridgian. the sw part of the platform emerged during the kimmeridgian, resulting in significant palaeokarstification (e.g. biokovo – tišljar et al., 1989) and establishment of conditions suitable for the formation of bauxite deposits (in w istria – polšak, 1965; tišljar & velić, 1987; velić & tišljar, 1988; tišljar et al., 2002). a similar situation was described in the n, ne part and along the platform margin in central and se slovenia (dozet & mišič, 1997), nw bosnia (vrhovčić et a b fig. 15 (a) massive reef–perireefal rudstones with abundant reef-building organisms (hammer for scale); (b) coral head in living position (scale bar = 5 cm). lithofacies c, breze column. 132 geologia croatica 55/2 133velić et al.: palaeogeographic variability and depositional environments of the upper jurassic... al., 1983), e herzegovina (natević & petrović, 1967) and w and n montenegro (vujisić, 1972; mirković & mirković, 1987). at the same time, the ne part of the platform in the karlovac area in croatia was influenced by totally opposite tendencies – after lengthy emergence, a large part of this area was submerged. formerly emergent areas, which existed from the middle lias to the kimmeridgian (bukovac et al., 1974, 1984; šparica, 1981; dragičević & velić, 1994, 2002), became a platform margin characterised by barrier coral–hydrozoan reefs. these kimmeridgian–tithonian biolithites along the n and ne margin of the adriatic carbonate platform are mostly preserved in a more or less continuous belt from w slovenia to se montenegro (dragičević & velić, 2002). in croatia they are documented in the vicinity of ozalj and karlovac (bukovac et al., 1974, 1984; dragičević & velić, 1994). reefal and peri-reefal environments gradually prograded toward the open tethyan realm, enabling the gradual migration of the platform margin towards the n and ne. in the central part of the adriatic carbonate platform, deeper areas were formed penecontemporaneously, in the form of two intraplatform troughs (probable pull-apart basins): one in the described eastern part of gorski kotar, and the other one stretching from the karlovac area towards the south, known as the “lemeš” trough (velić et al., 2002) which was, due to its connection with the open tethys and greater depth, characterised by a more significant pelagic influence. although outcrops of the gorski kotar trough are not very well preserved, it may be supposed that today it is oriented approximately nw–se, and that its western margin was completely surrounded by shallow-marine environments, while there is a possibility of at least a temporary connection with the lemeš trough towards the se. as previously described, oxfordian inner platform deposits were gradually replaced by thick bedded dark grey limestones with cherts comprising rare ammonites and radiolarians (and including relics of tuffitic material). towards the upper part of this sequence there is a gradual, but continuous increase of fine-grained interbeds composed of shallow-marine allochems (tišljar & velić, 1993; velić et al., 1994; tišljar et al., 1994; bucković, 1995), especially the biodetritus of reef-builders and ooids derived from hydrozoan–coral–gastropod–bryozoan reefs and surrounding ooid shoals. progradation of shallow material gradually completely infilled the former deep areas of intraplatform troughs which became overlain by typical shallow-water clypeina limestones. although there are similarities with penecontemporaneous “lemeš deposits”, some differences are remarkable: deposits in the area of gorski kotar show more characteristics typical for shallower environments (including hummocky cross stratification), beds are much thicker, cherts are less frequent and ammonites are very rare, since they were brought into this depositional area during temporary episodes of opening of the communication with the open sea. therefore, for these deposits velić et al. (19985) have proposed the name “tuk limestones” (named after the type locality in velika kapela mt.) to distinguish them from the “lemeš deposits”. sediments of the second, lemeš trough, today oriented approximately n–s, were deposited in a deeper bay of tethys, represented by thin-bedded to platy limestones interbedded with cherts, in some places with rich ammonite assemblages. these deposits are known by the name “lemeš deposits” (furlani, 1910; chorowicz & geyssant, 1972). although their underlying and overlying deposits are, due to younger tectonics and intense late-diagenetic dolomitization, frequently inadequately preserved, according to the field observations and literature data it is clear that in this case deeper-marine deposits also represent a sequence of variable thickness incorporated within shallow-marine deposits (e.g. at plješevica mt. near bihać and n of udbina, in vicinity of donji lapac, at poštak mt., knin area, svilaja mt. and cetina valley). the lemeš trough was also surrounded by reefs producing an enormous quantity of bioclastic material, progradation of which caused the final infilling of the basin and re-establishment of shallow environments. the inner part of the platform, i.e. the spacious area between emerged parts of the platform and the reef belt surrounding intraplatform troughs and platform margins, was characterised by continuous deposition of shallow-marine fossiliferous limestones, the so-called “cladocoropsis” and “clypeina–campbelliella” deposits. in the late tithonian, after the final infilling of the former intraplatform troughs and submergence of formerly emerged areas, these environments predominated over the entire platform. 4. discussion and conclusion from the aforementioned review of the geological events on the adriatic carbonate platform during the late jurassic two main conclusions may be drawn: (1) during the kimmeridgian, completely different environments were established over formerly more or less unified shallow-water environments, indicating synsedimentary tectonic control. near the sw margin some areas were emerged, in central parts intraplatform troughs had been formed, while contemporaneously along the ne margin formerly emerged areas (since middle lias) became 5 velić, i., tišljar, j., vlahović, i., velić, j. & koch, g. (1998): naslage gornje jure gorskoga kotara, like i primorja s osobitim obzirom na vapnence s rožnjacima [upper jurassic deposits of the gorski kotar, lika and primorje, including limestones with cherts – in croatian].– unpubl. report, archive of the institute of geology zagreb, 113/98, 101+242 p. 134 geologia croatica 55/2 135velić et al.: palaeogeographic variability and depositional environments of the upper jurassic... submerged. structural elements are masked by younger tectonics, hindering determination of the structural pattern. however, it is obvious that changes were gradual, probably as the consequence of a new tectonic regime, representing the beginning of the period characterised by inverse tectonics. existing lineaments in the platform basement began to reactivate under the new conditions of compression, i.e. transpressional stress regime, transforming former normal faults into faults with horizontal to subhorizontal movements. this resulted in formation of small pull-apart basins (i.e. intraplatform troughs), local emersions and facies differentiation. eustatic influences were subordinate during this period. subsequent infilling of the differentiated palaeorelief of the platform was enabled by very high organic production of reef belts surrounding the intraplatform troughs’ margins. (2) the studied succession of malmian deposits in the area of velika kapela mt. (gorski kotar) includes kimmeridgian deposits with pelagic influences – limestones with cherts. however, if these deposits represent part of the supposed long-lasting deeper marine labile belt (epiadriaticum – herak, 1986, 1989), existing from the late triassic to the eocene, they should be underlain and overlain by a deeper marine succession. detailed analysis of the stratigraphic succession of malmian deposits in se gorski kotar (the wider area of velika kapela mt.) undoubtedly confirmed the shallow-water origin of underlying and overlying deposits in all areas where continuous depositional successions are preserved. on the basis of the former investigations in the area of the lemeš trough (grimani et al., 1972; šušnjar et al., 1973; polšak et al., 1977; ivanović et al., 1977) a similar conclusion can be drawn, although it had more open connection with the open tethys realm. the desribed succession indicates the formation of temporary intraplatform troughs within a single carbonate platform. although, unfortunately, malmian deposits only crop out over a relatively small area (due to the complex structural pattern of the dinarides), on the basis of our investigation supported by available literature we can conclude that during the late jurassic (especially the kimmeridgian) the area of the adriatic carbonate platform was morphologically highly diversified. consequently, different environments, from emerged areas, shallow-marine to peri-reefal and deeper-marine, existed contemporaneously over a relatively small area, and only their careful detailed investigation enabled the correct interpretation of palaeogeographical relationships. palaeogeographic dynamics similar to those described in this paper have characterised the geological history of only some periods on the adriatic carbonate platform. this was especially true during the late cretaceous, when the area of the platform, as part of the apulian or adria microplate, gradually approached the laurasian continent, and the final disintegration of the platform took place. acknowledgement the authors are sincerely grateful to the reviewers, professor vladimir jelaska (faculty of sciences, university of zagreb) and dr. bojan ogorelec (geological survey of slovenia), for their comments and useful suggestions. 5. reference batten, d.j. (1996): palynofacies and palaeoenvironmental interpretation.– in: jansonius, j. & mcgregor, d.c. (eds.): palynology: principles and application. am. ass. of strat. palynol., 3, 1011–1064. bucković, d. (1995): upper jurassic carbonate facies succession at breze (velika kapela, croatia).– geol. croatica, 48/1, 9–16. bukovac, j., velić, i. & sokač, b. (1974): stratigrafski, tektonski i paleogeografski odnosi u području dugarese, barilovića i skradske gore (stratigraphy, tectonics and paleogeography of the region between dugaresa, barilović and skradska gora).– geol. vjesnik, 27, 59–77. bukovac, j., šušnjar, m., poljak, m. & čakalo, m. (1984): osnovna geološka karta sfrj 1:100.000. list črnomelj l33–91 (basic geological map of sfry 1: 100.000, the črnomelj sheet).– geološki zavod zagreb, geološki zavod ljubljana (1983), savezni geološki zavod beograd. buser, s. (1989): development of the dinaric and the julian carbonate platforms and of the intermediate slovenian basin (nw yugoslavia).– mem. soc. geol. ital., 40, 313–320. chorowicz, m.j. & geyssant, r.j. (1972): présence des couches de lemeš (calcaires à ammonites subméditerranéennes du malm) dans le lika (croatie, yougoslavie).– c. r. acad. sc. paris, 275, 731–734. dozet, s. & mišič, m. (1997): on malm bauxites and adjacent carbonate rocks in suha krajina (central slovenia).– rudarsko–metalurški zbornik, 44/3–4, 201–222, ljubljana. dragičević, i. & velić, i. (1994): stratigraphical position and significance of reef facies at the northern margin of the dinaric carbonate platform during the late jurassic and cretaceous in croatia and bosnia.– géologie méditerranéenne, 3–4, 59–63. dragičević, i. & velić, i. (2002): the northeastern margin of the adriatic carbonate platform.– geol. croatica, 55/2, 185–232. furlani, m. (1910): die lemeš-schichten. ein beitrag zur kenntnis der juraformation in mitteldalmatien.– jahrb. geol. reichsanst., 60/1, 67–98. 134 geologia croatica 55/2 135velić et al.: palaeogeographic variability and depositional environments of the upper jurassic... gorin, g.e. & steffen, d. (1991): organic facies as a tool for recording eustatic variations in marine fine-grained carbonates – example of the berriasian stratotype at berrias (ardèche, se france).– palaeogeography, palaeoclimatology, palaeoecology, 85, 303–320. grimani, i., šikić, k. & šimunić, a. (1972): osnovna geološka karta sfrj 1:100.000. list knin k33–141 (basic geological map of sfry 1:100.000, the knin sheet).– institut za geološka istraživanja zagreb (1966), savezni geološki zavod beograd. herak, m. (1986): a new concept of geotectonics of the dinarides.– acta geologica, 16/1, 1–42, zagreb. herak, m. (1989): dinaridi, mobilistički osvrt na genezu i strukturu (dinarides, mobilistic view of the genesis and structure).– acta geologica, 21, 1–83, zagreb. ivanović, a., sikirica, v., marković, s. & sakač, k. (1977): osnovna geološka karta sfrj 1:100.00. list drniš k 33–9 (basic geological map of sfry 1:100.000, the drniš sheet).– institut za geološka istraživanja zagreb (1967), savezni geološki zavod beograd. jerinić, g., jelaska, v. & alajbeg, a. (1994): upper cretaceous organic-rich laminated limestones of the adriatic carbonate platform, island of hvar, croatia.– am. assoc. petrol. geol. bulletin, 78, 1313–1321. matičec, d., vlahović, i., velić, i. & tišljar, j. (2001): sinsedimentacijska tektonika na jadranskoj karbonatnoj platformi (synsedimentary tectonics on the adriatic carbonate platform).– in: dragičević, i. & velić, i. (eds.): 1. znanstveni skup “karbonatna platforma ili karbonatne platforme dinarida” (1st scientific meeting “carbonate platform or carbonate platforms of dinarids”), knjiga sažetaka (abstracts), 46–50, zagreb. milan, a. (1965): korelacija malma ličke plješevice, senjskog bila i jugozapadnih padina velike kapele (corrélation du malm de la lička plješevica, du senjsko bilo et des versants sw de la velika kapela).– acta geologica, 5, 367–372, zagreb. milan, a. (1969): facijelni odnosi i hidrozojska fauna malma primorskog dijela sjevernog velebita i velike kapele (faziesverhältnisse und hydrozoenfauna des malms im küstenland des nördlichen velebit und velika kapela).– geol. vjesnik, 22, 135–217. mirković, m. & mirković, b. (1987): novi podaci o rasprostranjenju jurskih sedimenata u području sinjavine, durmitora i ljubišnje (new data about distribution of jurassic sediments in the area of sinjavina, durmitor and ljubišnja).– geološki glasnik, 12, 61–87, titograd. mirković, m. & vujisić, p. (1989): osnovna geološka karta sfrj 1:100.000. list žabljak k34–27 (basic geological map of sfry 1:100.000, the žabljak sheet).– zavod za geološka istraživanja titograd (1986), savezni geološki zavod beograd. mirković, m., kalezić, m. & pajović, m. (1977): osnovna geološka karta sfrj 1:100.000. list bar k34– 63 (basic geological map of sfry 1:100.000, the bar sheet).– zavod za geološka istraživanja titograd (1968), savezni geološki zavod beograd. mirković, m., pajović, m. & kalezić, m. (1979): osnovna geološka karta sfrj 1:100.000. list gacko k34–26 (basic geological map sfry 1:100.000, the gacko sheet).– zavod za geološka istraživanja titograd (1974), savezni geološki zavod beograd. natević, lj. & petrović, v. (1967): osnovna geološka karta sfrj 1:100.000. list trebinje k34–37 (basic geological map of sfry 1:100.000, the trebinje sheet).– geološki zavod sarajevo (1963), savezni geološki zavod beograd. nikler, l. (1965): entwicklung der jura in dem nordwestlichen teile der velika kapela.– bull. sc. acad. rsf yugosl. (a), 10/1, 3–4, zagreb. nikler, l. (1969): nerineje titona velike kapele (die nerineen des tithons von velika kapela).– geol. vjesnik, 22 219–227. nikler, l. (1978): stratigrafski položaj grebenskoga facijesa malma u sjeverozapadnim dinaridima (stratigraphic position of the malmian reef facies in northwestern dinarids).– geol. vjesnik, 30/1, 137–150. papeš, j. (1972): osnovna geološka karta sfrj 1:100.000. list livno k33–11 (basic geological map of sfry 1: 100.000, the livno sheet).– geološki zavod sarajevo (1967), savezni geološki zavod beograd. papeš, j. (1985): geologija jugozapadne bosne (geology of the southwestern bosnia).– geol. glasnik, pos. izd., 19, 166 p., sarajevo. poljak, j. (1936a): prilog poznavanju familije chaetetida iz titona velike kapele (ein beitrag zur kenntnis der chaetetiden aus dem tithon der velika kapela).– glasnik hrv. prir. društva, 41–48,105–117, zagreb. poljak, j. (1936b): prilog poznavanju titonskih hidrozoa velike kapele iz familije ellipsactinida (ein beitrag zur kenntnis der hydrozoenfamilie ellipsactinidae aus dem tithon der velika kapela gebirge).– glasnik hrv. prir. društva, 41–48, 255–271, zagreb. poljak, j. (1944): o naslagama titona i njihovoj fauni s područja velike kapele u hrvatskoj (über die tithonbildungen und ihre fauna aus dem gebiete des velika kapelagebirges in kroatien).– vjestnik hrv. drž. geol. zav. i hrv. drž. geol. muz., 2–3, 281–340, zagreb. polšak, a. (1965): stratigrafija jurskih i krednih naslaga srednje istre (stratigraphie des couches jurassiques et crétacées de l’istrie centrale).– geol. vjesnik, 18/1, 167–184. polšak, a., juriša, m., šparica, m. & šimunić, an. (1977): osnovna geološka karta sfrj 1:100.000. list bihać l33–116 (basic geological map of sfry 1: 100.000, the bihać sheet).– institut za geološka istraživanja zagreb (1967), savezni geološki zavod beograd. raynaud, j.-f., lugardon, b. & lacrampe-couloume, g. (1989): structure lamellaires et bacteriés, composants essentiels de la matière organique amorphe des roches mères de pétrole.– bull. centres rech. explor.prod. elf aquitaine, 13/1, 1–21. šparica, m. (1981): mezozoik banije, korduna i dodirnog područja bosne (geology of the mesozoic areas of kordun, banija and nw bosnia, yugoslavia).– nafta, spec. publ., zagreb, xii+245 p. šušnjar, m., bukovac, j., nikler, l., crnolatac, i., milan, a., šikić, d., grimani, i., vulić, ž. & blašković, i. (1970): osnovna geološka karta sfrj 1:100.000. list crikvenica l33–102 (basic geological 136 geologia croatica 55/2 137 map of sfry 1:100.000, the crikvenica sheet).– institut za geološka istraživanja zagreb (1969), savezni geološki zavod beograd. šušnjar, m., sokač, b., bahun, s., bukovac, j., nikler, l. & ivanović, a. (1973): osnovna geološka karta sfrj 1:100.000. list udbina l33–128 (basic geological map of sfry 1:100.000, the udbina sheet).– institut za geološka istraživanja zagreb (1967), savezni geološki zavod beograd. tappan, h. (1980): the paleobiology of plant protists.– freeman, san francisco, 1028 p. tissot, b.p. & welte, d.h. (1984): petroleum formation and occurrence.– 2nd ed., springer-verlag, 699 p. tišljar, j. & velić, i. (1987): the kimmeridgian tidal-bar calcarenite facies of western istria (western croatia, yugoslavia).– facies, 17, 277–284. tišljar, j. & velić, i. (1991): carbonate facies and depositional environments of the jurassic and lower cretaceous of the coastal dinarides (croatia).– geol. vjesnik, 44, 215–234. tišljar, j. & velić, i. (1993): upper jurassic (malm) shallow-water carbonates in the western gorski kotar area: facies and depositional environments (western croatia).– geol. croatica, 46/2, 263–279. tišljar, j., velić, i. & sokač, b. (1989): einflusse von emersionen auf die flachwasserkarbonatsedimentation im malm (oberer jura) des biokovo-gebirges (sudkroatien, jugoslawien).– geol. paläont. mitt. innsbruck, 16, 199–201. tišljar, j., velić, i. & vlahović, i. (1994): facies diversity of the malmian platform carbonates in western croatia as a consequence of synsedimentary tectonics.– géologie méditerranéenne, 21/3–4, 173–176. tišljar, j., vlahović, i., velić, i. & sokač, b. (2002): carbonate platform megafacies of the jurassic and cretaceous deposits of the karst dinarides.– geol. croatica, 55/2, 139–170. turnšek, d. (1975): malmian corals from zlobin, southwest croatia.– palaeont. jugosl., 16, 7–23, zagreb. turnšek, d. (1997): mesozoic corals of slovenia.– zrc sazu, ljubljana, 513 p. turnšek, d., buser, s. & ogorelec, b. (1981): an upper jurassic reef complex from slovenia,yugoslavia.– sepm, spec. publ., 30, 361–369. tyson, r.v. (1995): sedimentary organic matter. organic facies and palynofacies.– chapman & hall, 615 p. velić, i. (1977): jurassic and lower cretaceous assemblagezones in mt. velika kapela, central croatia.– acta geologica, 9/2, 15–37, zagreb. plate 1 palynofacies of kimmeridgian deposits of velika kapela mt. 1 a fragment of a microbial mat lamina. magnification 200x. 2 leiosphaeridia sp., aom, lath-shaped black particle, semiangular woody tissue. magnification 800x. 3 tasmanites sp., aom. magnification 800x. 4 escharisphaeridia sp. magnification 800x. 5 corollina (classopollis) sp. magnification 400x. 6 moderately structured lath-shaped woody tissue, aom. magnification 400x. 136 geologia croatica 55/2 137 1 3 5 2 4 6 velić et al. plate 1 138 geologia croatica 55/2 velić, i. & sokač, b. (1974): on the tripartite subdivision of the malm in mt. velika kapela (croatia).– geol. vjesnik, 27, 143–150. velić, i. & sokač, b. (1978): biostratigraphic analysis of the jurassic and lower cretaceous in the wider region of ogulin, central croatia.– geol. vjesnik, 30/1, 309–337. velić, i. & tišljar, j. (1988): litostratigrafske jedinice u dogeru i malmu zapadne istre, zapadna hrvatska, jugoslavija (lithostratigraphic units in the dogger and malm of western istria).– geol. vjesnik, 41, 25–49. velić, i., vlahović, i. & tišljar, j. (1994): late jurassic lateral and vertical facies distribution: from peritidal and inner carbonate ramps to perireefal and peritidal deposits in se gorski kotar (croatia).– géologie méditerranéenne, 21/3–4, 177–180. velić, i., vlahović, i. & matičec, d. (2002): depositional sequences and palaeogeography of the adriatic carbonate platform.– mem. soc. geol. it., 57, 141–151. vlahović, i., velić, i., tišljar, j. & matičec, d. (2001): utjecaj sinsedimentacijske tektonike na malmsku paleogeografiju jadranske karbonatne platforme (malmian palaeogeography of the adriatic carbonate platform as a consequence of the synsedimentary tectonics).– in: dragičević, i. & velić, i. (eds.): 1. znanstveni skup “karbonatna platforma ili karbonatne platforme dinarida” (1st scientific meeting “carbonate platform or carbonate platforms of dinarids”), knjiga sažetaka (abstracts), 51–54, zagreb. vlahović, i., tišljar, j., velić, i. & matičec, d. (2002): the karst dinarides are composed of relics of a single mesozoic platform: facts and consequences.– geol. croatica, 55/2, 171–183. vrhovčić, j., vujnović, l. & mojičević, m. (1983): osnovna geološka karta sfrj 1:100.000. list ključ l33–130 (basic geological map of sfry 1:100.000, the ključ sheet).– geoinženjering sarajevo (1978), savezni geološki zavod beograd. vujisić, t. (1972): osnovna geološka karta sfrj 1:100.000. list nikšić k 34–38 (basic geological map of sfry 1: 100.000, the nikšić sheet).– zavod za geol. i geofiz. istraž. beograd (1967), savezni geološki zavod beograd. vujnović, l. (1980): osnovna geološka karta sfrj 1:100.000. list bugojno l33–143 (basic geological map of sfry 1:100.000, the bugojno sheet).– geoinženjering sarajevo (1975), savezni geološki zavod beograd. i geol. croat. 49/2 211 2 15 7 fi gs. i tab. i zagreb 1996 i scientific paper a geodetic-gravimetric method for better modelling of geological structures in the test area of croatia kres imir colic. tomislav basic. bosko pribicevic and damir medak proceed[ngs key words: gravity fi e ld mocielling, verti cal clcllcc­ lions, gravity anomalies, 3d seismics, geophysical prospection, bjclovar depression, croatia. abstract a new approach to the modelling oflhc earth's crust, especially ils upper portion, uti lising different kinds of geodeti c (vert ical den ec­ liol1 components, geoid su rface), gravimetric (bouguer and other gravity anomalies) and geo ph ys ica l (3 d seis mi c from bore ho le prospecting) data is presented in ihis paper. thi s scient ific research formed part of a special contract between the faculty of geodesy and ina-naf1ap lin, wit h th e aim of establ ishing the grav ity field over a test area in northern croati a. [t shoul d improve th e geo physica l prospection for minerals, part icu larly in the fi eld of hydrocarbo n exp loration. 1. introduction detailed knowledge of the earth' s crusta l structure, espec ially in the layers closest to its surface, is very important in geodesy, but also in geophysics, e,g, for hydrocarbon exploration in some local areas . in order to increase the quantity and quality of additional informa­ ti on abo ut mass distribution for poss ible oil -explo­ ration , a broad range of scientific research has been undertaken by the faculty of geodesy over the last four years in the area of the bilogo ra hill s and bjelovar depress ion. all previously existing geophysical and gravimetrical information was combined with carefully planned new geodetic and astronomi cal measurements. this undertaking req uired special methodology, based on the ex istin g tc-eomputer program (forsberg, 1984). whieh has been developed and success full y applied l . 2. data there arc a number of existing data sets for the test­ area, som e of whic h were taken from the ex isting archi ves : gravim etric measurements, borehole dens ity university of zagreb, faculty of geodesy, kac iceva 26, hr 10000 zagreb, croatia. data, and a p::ut of rs7 and pt depths. however, a lot of necessary file s required const ruction ; includi ng those 1'01' a digital te rrain model, digital density illodel of upper crust masses, digitising of pt and rs7 shapes in the larger part, filtering and re-ealculation of bouguer gravi ty anomalies and complete determination of astro­ geodet ic deflections of the vertica l. the data files used refer to the following: a) a digital terrain model with block resolution of 4x5 arcsec (app, iiox120 m) obtained from the digitised based state map 1:5.000 (see fig. 1), b) a di gital mod el of terti ary base (pt) shape (more than 220.000 discrete points). e) a digital model of rs7 shape (more than 210.000 dis­ crete points), d) a digital surface density model recalculated from the existing 2.5x2.5 arc sec model (fi g. 2). e) a digital density model of rs7 and pi shapes, empiri­ cally obtained from the existing borehole dens ity data in the tes t area (fig. 2). d gravimetrical measurements at more than 30,000 points, g) astro-geodetic deflec tions of vertical at more than 50 points. 3. methodology the gravi metric approach in hydrocarbon prospect­ ing has been known for a long time. however, the den­ s ity contrast be tween normal and oil-filled strata was usually based on ly on the gravi ty anomalies one (verti­ cal) component of the gravitational vector. in the pre­ sent research , the idea of using all three vector compo­ nents (vertical + both, w-e and n-s, components of the veltical deflection sand 11) was applied. it is based on its stronger sensibility for small variations in mass-di s­ tribution and also smaller loses of accuracy caused by necessary reductions. for ihis purpose, precise astro, colic. k .. basic. t .. prib icevic. b. & medak . d. t 1995), app[ying of th e new combined geodetic-gravimet ri c method in determining of geologic-geophysical st ructu res ill chosen test area in croat ia.unpublished final report for oil company lna -nafta­ plin, faculty of geodesy, university of zagrcb, 38 p. 212 surface heights pt depths //<:fp ~~~ /~:,., fig. i digilal modcts of surface heights, rs7 and pi depths (in m), !lamica l measurements wilh the telescope zenith cam­ era (tz k2) and partly with the zeiss ni2-astrolab appa­ ratu s we re pe rformed on more than 50 points over our les t-arca (fig 3). art e r de te rmining deflections of the vertical al the measured po ints and calcu lating bou guer anoma li es fig. 3 measured aud ca lcu lated vert ical de fl ecti on po in ts in the lest :irca (in arcscc). geologia cro:llica 49n surface density fig. 2 digi tal density model s of earth 's sur face, rs7 and pi shapes (in kg/illl). us ing grs 80 (moritz, 1980 ) fo r the da ta se ts men­ tioned above , we look advantage of the pre pa red sur­ fa ce de ns ity mode l (colic e t ai. , 1992) as we ll as empiri cally obtained de nsity mode ls a l rs7 and pi depths (jelic, 1984 ), in calc ul a ting te rrain influe nces. the lls llal method way of mass-mod e llin g ass um es a densllyanomalies h '55. [ i'ss . " " fig.4 modelling of topog r<t phic illnsscs. colic. basic. pribicevic & ,v1edak: a geodetie-grnvimctric method for better mockllitlg ... 213 46 45 45 '5 46 4590! 45801 ./._ ll c~ , ~,' '1 .~.j ' 57oj -~. 40 1650 1660 16 70 1680 1690 1700 1710 constant density for approximating polyhedra. the aim of the requi red method was the usc of variable density in all three directions (fig. 4). in this case, the earth' s crustal masses, i.e. between [he earth 's surface and the mohorovicic discontinuity, arc presented as three layers, characterized by heights ii (digita l terrain model) and depths dss, and dss2 of the rs7 and pi surfaces, followcd by the corresponding dens iti es pss, and pssr the third layer of the earth 's crust, between dss2 and mohorovicic's discontinuity, was assumed to have thc constant density pssj equal to the density of the referencc body, i.c. the reference ellipsoid with the reference crust density po' therefore, [he topographic effect is more complex: bes ides the el imi nation of surface topography influences, effects or "covered" topographies (which lead [0 some compensa­ tion) arc al so el iminated. in this way a topograph ic reduction was defined in addition to other physical ~,o "0 ~,, ~~ ~() ?[", .!() '" " , , , , , , o o 1 0 fig . 5 a) topographic correction from 3d density model (i ll 10-5 ms·2) : b) deflections of vertical rrotll 3d : 05 00 density model (in arcscc) . effects which fu lly utilize information on ncar-surface (see brkic, 1994 for details). the input -data was data file s forming coarse and fine grids of the following data: relief heigh ls, rs7 and pt depths with corresponding density values. all coarse grids cover the area 45.00°-46.75° (latitude) with 15.0°­ is .so (longitude) with a 60x90 arcsec raster. the fin e grids arc given in a 4x5 arcsec raster covering the area 45.50°-46.25" (latitude) and 16.25°-17.50° (longitude) . the computational area is defined by 45 .625°-46.125° (latitude) and 16.375°-17 .375° (longitude). a special software package in fortran77 was devel­ opcd to provide thc numcrical solution for th is method­ ology. it uses even coarscr grids of the above men ­ tioned data , resulting in a larger arca of computation. this program facilitates the calculation of the all impor­ tant topographic effects: topo-isostatic, relief correction and [he so called residual correction (rtm). filename mean sf. dev_ min max description rdtms 160.80 79.56 91.00 863.00 d igita l terrain model fdllsrs7 161 3.61 1382.81 -6097.00 479.00 rs7-deplhs model fdbspt 1981.81 1569.40 -6848.00 722.00 pt-depths model fddms 2 121.16 168.64 1970.00 2800.00 density model surface table t the final infddmsrs7 2250.65 14 1.27 1970.00 2800.00 density model surface/rs7 put data files (heigilts and depths in fddmrs iyr 2403 .12 2 14.41 1970.00 2800.00 density modelrs7ipt metres. dens iti es in kgm·3) . \"j <'0 4. results the final input data fil es arc not the most important resull but deserve to be mentioned with their statistics crabl e i). we have computed output grids of topographic eor­ reclions (complete bouguer anomaly) and total deflec­ tions of the vertical (fig. 5), as well as geoid undula­ tions. the bouguer anomaly map is the result of the interpolation of more than 24,000 filtered gravimetric measurements involved with a 3d geological model. the mean value is 21.40 x 10-5 ms-2 , standard deviation ±9.80 x 10-5ms·2, maximal value 60.89 x 10-5ms-2 and minimal value -9.81 x 10-5ms -2 . a digital model of bouguer anomalies was also calculated for the constant dcnsities of 2120 kgm-:> and 2670 kgm-3• 'fhe calcu lated geoid surface using a 3d-geological model shows that the undulations vary approximately 40 cm over ihe entire area. the most important result is a digita l model of vertical dellections based on 53 mea­ sured points (see fig. 6). the maximal difference be tween the measured and topographic deflections is 8.92 arcsec , minimal 0.39 aresec, with standard devia­ tion ±1.8 i arcscc. 5. conclusions the main aim of this rcsearch was to acquire new information for potential hydrocarbon exploration. arter careful examination it was discovercd that the residual map (d ifferences between measured and calcu­ latcd deflections of vertical) shows a very significant anomaly of 6 arcsec near bjelovar. this cannot be intcrpreted as a relief disturbance (because the area is geologia croatica 49/2 fig. 6 differences between measured and calculated vertical deflections (in aresee). flat), and more detail ed measurements and further investigations are required. it is very inte resting that the same narrow area is highlighted on the map of differences between bouguer anomalies with a 3d density model and bouguer anom­ alies with a constant density model (2120 kgm -3), see fig. 7. the two different approaches tend to have the same results over the same local area, thus justifying both the invesment and effort involved in this multidis­ ciplinary project. acknowledgment we would like to thank mr sc. mario brkic for his contribution in this research, dr. rene porsberg for provid ing his excellent tc-software package and prof. wolfgang torge, ire. univcrsity of hannover for the lean of the telescope zenith camera (tzk2). this inter­ esti ng research project was g ranted by the croatian state oil-company "ina-naftaplin ". 6. references brkic, m. (1994): an improved method of earth's crust masses modelling ror geodet ic and geop hysi­ cal purposes.-unpublished m.sc. thesis, faculty of science, university of zagreb, 9s p. colic. k .. pribicevic, b .• ratkaj ec. i'vl. , sto­ par, r. , sumanovac, f. & velic. j. (j992): init ial digi ta l density model of the surrace earth's core masses in the test area "slovenia and surround­ ing palt of croatia" for the regional uses in physical geodesy.geodetski lis t. 46/3, 263-281, zagreb. (:oli~, basic, pribii::evic & mcd:tk: a geodelic-gr:liiimelric mcthod for ileuer modelling ... 2 1 s fig. 7 differences or i30uguer anomalies: dgjd-dg212o (in i0 5ms·\ r:orsberg , r. (1984) : a study of te rra in reduc­ tions, density anomali es and geophysica l in ver­ sion meth ods in gravity field modelling.depart­ ment of geodetic sc ience and surveying, ohio state university, colu mbus, report, 355, 129 p. jellc, k. ( 1984) : odnos gustocc i poroznosti s dubi­ nom iitostratigrafskih formacija savskc i drav skc potoline.naha, 35, 637-643, zagreb. 4.00 3.00 2.00 moritz, h. (1980): geodetic refere nce system 1980.bulletin geodesique, 58/3, 388-398. 216 geologia croatica 49n jurkovic.indd 223 � ab stra ct in the saski rad barite-siderite ore deposit, hg-tetrahedrite is the main ore mineral, pyrite and some others are only accessories. two tetrahedrite samples (fresh and weathered) have been analysed in detail: major and minor components, constituent trace elements, ree, and δ34scdt values. the following microconstituents have been detected: ni 71 ppm (in fresh sample) and 70 ppm (in weathered sample); co 113 and 90 ppm; cd 27 and 20 ppm; w 20 and 5 ppm, bi 2500 and 1613 ppm; se >100 and 72 ppm and au 11 and 9 ppm. these values have been compared with the only currently available analysis of hg-tetrahedrite from the duboki vagan near kreševo in the mid-bosnian schist mts. (mbsm) carried out by jurković et al. (2010): ni 266.2 ppm; co 63.5 ppm, cd 319.6 ppm; bi 1466.0 ppm; au 38.96 ppm which also agrees with our analysis of hg-tetrahedrite from the brixlegg barite deposit in tyrol, austria: co 234.4 ppm; cd 160.5 ppm; w 6.7 ppm; sn 1.0 ppm; bi 909.1 ppm; se > 100 ppm and au 2.3 ppm. the δ34scdt isotope values of six tetrahedrites from the saski rad are on average –10.11‰, those of three tetrahedrites from the duboki vagan –10,05‰ and of the tetrahedrite from the brixlegg deposit –1.60‰. the σree content is lower in two analysed tetrahedrites from the saski rad deposit (10 ppm) compared to the tetrahedrite from duboki vagan (15 ppm) and the tetrahedrite from brixlegg (17.4 ppm). the analysed barite sample from the saski rad deposit does not contain microconstituents typical of hg-tetrahedrite. the distribution and genetic signifi cance of some trace elements, tetrahedrite microconstituents, ree and siderite isomorphic components in the seven most important genetic and paragenetic types of ore deposits in the mbsm and south-eastern bosnia have been commented upon. keywords: mercurian tetrahedrite, content of co, ni, w, cd, se, ag and au, sulphur isotope compositions, saski rad and rad barite-siderite deposits, palaeozoic, mid-bosnia cobalt, nickel, tungsten, cadmium, selenium, silver and gold-bearing mercurian tetrahedrite from the saski rad barite–siderite deposit in the mid-bosnian schist mts. � ivan b. jurković1, vesnica garašić1 & ivan m. jurković2 1 faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, 10000 zagreb, croatia 2vladimira ruždjaka 25, 10000 zagreb, croatia doi: 104154/gc.2011.19 geologia croatica 64/3 223–237 7 figs. 11 tabs. zagreb 2011 geologia croaticageologia croatica 1. introduction in the framework of the variscan metallogeny in the midbosnian schist mts. (mbsm) and south-eastern (se) bosnia, particular attention has been paid to the problem of tetrahedrites, the main ore minerals of numerous barite and barite-siderite ore deposits (jurković, 1956; jurković et al., 2010). two completely different tetrahedrite types have been discovered: a) an initial, older type without mercury characterised by positive δ34scdt values ranging from +3.28 to +4.0‰ (kubat et al., 1979/80; jurković et al., 2010); and b) a second, younger type mercury-bearing tetrahedrite, characterised by strongly negative δ34scdt values ranging from –4.95 to –15.40‰ (jurković et al., 1997). geologia croatica 64/3geologia croatica 224 at present, 16 quantitative chemical analyses of tetrahedrite samples from the mbsm have been performed and published (poech, 1900; vesely, 1921; jurković, 1956, 1960, 1986; jurković & miko, 1997; jurković et al., 1997). these analyses included only eight major constitutive elements: cu, fe, zn, hg, ag, sb, as and bi (rarely au). tetrahedrite samples have been taken from the following barite and barite-siderite ore deposits: two older tetrahedrite samples (without mercury) from trošnik (2) and 14 younger hg-tetrahedrite samples from maškara (5), saski rad (2), sabiljine pećine (1), zlatarica (1), točak (1), kostajnica (1), duboki vagan (1), dubrave (1), vidici (1). chemical compositions were obtained through various analytical techniques: a) quantitative wet chemical analyses (5 samples); b) the pixe method with scanning proton microprobe (5 samples); and c) atomic absorption spectrophotometry (aas) and icp–aes after br2–hcl digestion (6 samples). the analytical data obtained from these 16 tetrahedrite samples, demonstrate signifi cant differences resulting from a) the distance of the ore deposit from the long and deep voljevac fault; b) the stratigraphic level (age) of the host rock; c) the type of the host rock (carbonates or metaclastics); d) being overprinted (or not) by ascending mercurybearing fl uids. the average values of hg, fe, zn and as in the tetrahedrite samples from the barite-siderite deposits of the four most important ore regions of the mbsm are represented in table 1. evidently, the mercury content in the tetrahedrite crystal lattice depends on the distance of the deposit from the voljevac fault. the maškara vein (no 6) and the mračaj vein (no 46) are the biggest and the richest hg-tetrahedrite ore deposits in the mbsm. the maškara vein is 2 km and the mračaj vein only 0.5 km away from the fi rst order voljevac fault. the values of the same elements in tetrahedrites from the gemericum (slovakia) (cambel-jurkovsky et al., 1985) and from the brixegg, tyrol (austria) (lukas, 1971; gstrein, 1983; frimmel and papesh, 1990) are included in table 1 for comparison. our initial detailed study of the tetrahedrite genesis in the mbsm and se bosnia, demanded additional, more precise analytical methods which ensure the determination of au intergrowths and microconstituents in the tetrahedrite samples such as ni, co, cd, sn, w, se, te, another 31 trace elements and 14 rare earth elements. the fi rst such determination has been done on hg-tetrahedrite from the duboki vagan deposit (d-vagt sample) in which the following microconstituents have been detected: 266 ppm ni, 63.5 ppm co, <0.5 ppm w, 313 ppm cd, <1.0 ppm sn, <0.5 ppm se and 39 ppm au (jurković et al., 2011). in this paper, our objectives are to investigate in great detail the chemical composition of hg-tetrahedrite from the smaller barite-siderite deposits saski rad and rad. they present the south-eastern prolongation of the maškara ore deposit, the biggest hg-tetrahedrite deposit in the mbsm, located in the silurian–devonian (s,d) metaclastic rocks, 9 km se of the town of gornji vakuf. in order to elucidate its genesis, hg-tetrahedrites will be compared with hg-tetrahedrite samples from other maškara vein type deposits; the duboki vagan (kreševo) and brixlegg (tyrol) barite deposits. 2. geological setting 2.1. geology of the gornji vakuf area the gornji vakuf area is situated in the middle part of the south-western mid-bosnian schist mts. (fig. 1.a). fig. 1.b presents a simplifi ed geological map, compiled from data published by sofilj & živanović (1979) and sofilj et al. (1980). the oldest rocks of the area are chlorite-sericite schists and sericite-chlorite-quartz schists, locally interlayered by metasandstones and, in the area of gromilica, by quartzites. table 1: average values (in wt.%) of hg, fe, zn and as in the crystal lattices of tetrahedrite samples from the barite-siderite deposits located in the four most important regions of the mid-bosnian schist mountains (mbsm) (jurković et al., 1997). abbreviations: lm = limestone; do = dolomite; sch = metaclastic rocks (phyllite, metasandstone); s = silurian; d = devonian; n = number of analysed tetrahedrite samples; nmrs = numerous; av = average value; rg = range; v. fault = voljevac fault. ore district n hg wt. % fe wt. % zn wt. % as wt. % host rock age distance to voljevac fault sabiljine pećine nw of the gornji vakuf 1 av rg 7.35 1.10 4.17 2.04 lm (do) d2 0.5–1 km maškara – saski rad se of gornji vakuf 8 av rg 5.14 (3.69–7.58) 4.29 (2.80–5.77) 0.24 (tr – 0.72) 3.82 (1.50–5.84) sch s,d 0.5–2 km dusina, deževice kostajnica 5 av rg 1.62 (0.63–3.40) 1.89 (0.82–3.40) 3.64 (0.77–6.18) 3.05 (0.43–5.41) do (lm) d2 10–15 km kreševo, tarčin 5 av rg 1.95 (0.33–3.80) 2.27 (0.52–4.15) 3.01 (1.21–4.64) 1.97 (1.41–2.73) do (lm) d2 15–20 km trošnik, fojnica 3 av rg 0.29 (0.03–0.63) 6.77 (6.00–7.42) 2.24 (1.82–2.41) 1.05 (0.90–1.20) do (sch) s,d >20 km mbsm 22 av rg 3.07 (0.03–7.58) 3.74 (0.52–7.42) 2.09 (tr. 6.18) 2.77 (0.43–5.84) jurković et al. (1997, 2010) rudnány, gemericum, slovakia nmrs av rg 9.70 (0.0–19.80) 2.59 (0.2–5.8) 0.79 (0.1–4.0) 4.87 (2.3–4.7) cambel & jurkovsky (1985), radvanec et al. (2004) brixlegg, tyrol austria nmrs av rg 1.80 (0.0–15.0) 2.60 (2.5–3.0) 5.40 (4.0–6.0) 6.20 (5.0–6.0) lukas (1971), gstrein (1983), frimmel & papesh (1990) jurković i.b. et al.: cobalt, nickel, tungsten, cadmium, selenium, silver and gold-bearing mercurian tetrahedrite from the saski rad... geologia croatica 225 in the area of the cvrče village and in the desna valley younger rocks and slates occur. the area near krugljača is characterised by the occurrence of sandy sericite-chlorite schists and schistose sandstones. limestone and dolomite lenses are very rare. all these rocks are attributed to the silurian–devonian metamorphic rocks of greenschist facies (s,d in fig. 1.b). in the mt. vranica area, the silurian–devonian complex is tectonically covered by devonian limestones with subordinate dolomites. the lowest part, found only in the suvodol valley, is built up by the fossiliferous lower devonian platy limestones (d1). the middle devonian consists of zoogene, massive and rarely bedded limestones and subordinate dolomites (d1,2). on the geological map, prozor sheet, car bon iferous rocks have not been registered, although živa nović (1972) presumes that younger parts of the silurian–devonian complex may belong to the lower carboniferous. shallow subvolcanic rhyolite (denoted as x in the fig. 1.b) intrusions and extrusions are numerous. jurković et al. (2010) proved by 87sr/86sr ratio that they represent an s-type granitoid magma as previously assumed by majer & garašić, 2001. they are mostly transformed into metafigure 1: a) position of the mid-bosnian schist mountains (mbsm) inside the republic of bosnia and herzegovina; b) simplifi ed geological map of the gornji vakuf area from the prozor sheet compiled by sofilj & živanović (1979). positions of the 47 ore occurrences, their parageneses, strike and dip are marked by jurković et al. (1994). the maškara ore deposit is denoted by the number 6, rad by number 7 and saski rad by number 8. colours are according to the commission for the geological map of the world (cgmw) and the international commission on stratigraphy (ics) (cmyk colour code, 2008). abbreviations: s,d – upper silurian–lower devonian schist complex; d1 – lower devonian; d1,2 (d) – middle devonian carbonate complex; md1,2 – marbleized limestones; x – rhyolite; x’ – metarhyolite; nq – quartzkeratophyre; p3 – upper permian sediments; t1,2 – lower and middle triassic; gf – fl uvioglacial placers; ore occurrences: nos 1–15 (in fig. 1.b) = siderite ± barite + tetrahedrite (in s,d); nos 16–24 = barite ± siderite + tetrahedrite (s,d); nos 25–40 = barite ± tetrahedrite (d1,2); nos 41–43 = bartie ± tetrahedrite (p3–d1,2 thrust/fault zone); nos 44–46 = siderite ± barite + tetrahedrite (p3–s,d thrust/ fault zone); no 47 = metamorphogenic quartz deposit (s,d). geologia croatica 64/3geologia croatica 226 rhyolites (denoted as x’ in the fig. 1.b) by variscan regional metamorphism. keratophyres (nq), are much rarer, younger than (meta)rhyolites and belong to the permian. upper permian formations are unconformably underlain by older palaeozoic rocks: breccias, conglomerates, porous limestones ± gypsum, coloured subgraywackes, subarkoses, siltstones. the lower triassic (t1) is composed of siltstones and limestones, and the middle triassic (t2) by limestones, dolomites and a volcanic-sedimentary formation. 2.2. ore deposits of the gornji vakuf area in the gornji vakuf area jurković et al. (1994) have registered 47 ore occurrences (fig. 1.b) of the following genetic types: 1) sedimentary gold deposits: a) quaternary gold-bearing fl uvial deposits; b) gold-bearing diluvial terraces; and c) uppermost pleistocene (wuerm) glacial formations (ruecker, 1896; jurković, 1951; radusinović, 1960; jurković et al., 1994). 2) hydrothermal ore deposits (nos 1–46 in fig. 1.b): a) the maškara vein type, containing siderite, barite and hg-tetrahedrite, located se of gornji vakuf in metapelites and metapsammites of the lower parts of the silurian–devonian complex (nos 1–15); b) the cvrče-borova ravan type, containing barite, siderite and hg-tetrahedrite, located in metaclastic rocks of the higher parts of the silurian–devonian complex (nos 16–24); c) the sabiljine pećine type, containing only barite, while hg-tetrahedrite is a very subordinate or even accessory mineral. this type is located in the partly dolomitised middle devonian limestones, (nos 25–43); and d) the mračaj type, which is characterised by a barite-siderite-hg-tetrahedrite paragenesis. this type is located along the voljevac fault zone (the tectonic contact between the upper permian and lower palaeozoic) (nos 44–46). 3) metamorphogenic quartz deposit (no 47 in fig. 1.b) the research here is restricted to ore occurrences situated in the triangular area between the western slopes of the vrbas river, western banks of the river desna and eastern banks of the river dragučina, a western tributary of the vrbas river. there are hydrothermal ore deposits of the maškara paragenetic type (nos 5–15 in fig. 1.b) and the cvrče-borova ravan paragenetic type (nos 16–24) present in this (~60 km2) area. taking into consideration two published detailed studies of the maškara vein (katzer, 1907; jurković, 1960), research samples were selected from the old medieval and austrian mines rad and saski rad, which are a prolongation of the maškara vein. 2.3. general characteristics of the maškara vein type from 15 ore occurrences (nos 1–15) attributed to this paragenetic type, the biggest one is the maškara vein (nos 6). it is 250 to 350 m long, vertically over 110 m high, 0.1 to 1.0 m thick, dipping 75°/40–60°. this vein produced 8.0 tons of crude ore with 25% of hg-tetrahedrite. the average content of hg-tetrahedrite was 9–15 vol.% or 10–16 wt.% in barite crude ore and 20–60 vol.% or 15–65 wt.% in siderite crude ore (katzer, 1907; jurković, 1960). the rad (no 7) and saski rad (no 8) are ore occurrences which belong to the maškara genetic type. the quantitative relationship of the main constituent elements in the hg-tetrahedrite of the rad and saski rad deposits is very similar to that in the hg-tetrahedrite from the maškara deposit, indicating that these deposits might represent the broken parts of the maškara ore vein. the maškara vein lies at the absolute altitudes of +820 to +930 m, the rad deposit at an altitude of +1000 m, and the saski rad deposit at +1070 m. on the western banks of the river desna (a tributary of the vrbas river), the other ore deposits belonging to the ma š ka ra paragenetic type are located: desna (no 9 in the fig. 1.b), daganj creek (no 10), valice village (no 11), valice mlinovi (no 12) and kulentaš (no 15). in these deposits, siderite is the main mineral with single hg-tetrahedrite grains, net-like aggregates or interrupted interlayers of tetrahedrite. barite is abundant, but subordinate. ore occurrences nos 10 and 11 contain an increased quantity of quartz ± pyrite and a decreased amount of tetrahedrite (jurković et al., 1994). all these veined ore occurrences stretch nne–ssw or ne–sw with a very steep dip. they are short, shallow and very thin veins (from 0.1 to 0.2 m thick). their outcrops lie at altitudes of +1100 m, hosted by the rocks of the lower part of the silurian–devonian complex (phyllite and similar rocks). the laznice ore occurrence (no 13) at +1200 m altitude, and crkvice (no 14) at +950 m, represent an open jointing system (width 0.1–1.0–3.0 m) which is only partly fi lled with clay gangue, fe and mn hydroxides, ankerite, calcite and ore fragments. in the cvrče-borova ravan area, at altitudes of +1050– +1350 m, similar ore occurrences have been discovered, characterised by barite as the dominant ore mineral, whereas siderite ± quartz are subordinate minerals. hg-tetrahedrite is scarce or very subordinate. the following ore deposits and occurrences belong to this paragenetic type: ladina voda (no 16), kašli brdo (no 17), djamuš brdo (no 18), cvrče village (no 19), cvrče-zaganj (no 20), borova ravan-bosnjačica (no 22) and borova ravan (no 23). all these veins strike nnw–sse or nw–se, dipping towards the ne/25– 45°. they are all very thin (nos 19 and 23 are 0.05–0.10 m thick), only the djamuš brdo vein (no 18) is somewhat thicker (0.10–0.40 m). all ore occurrences are hosted by metasandstones and schists are attributed to the higher parts of the silurian–devonian complex. živanović (1972) claims that these rocks belong to the lower carboniferous. at borova ravan-guvnanica (no 21) and ričica (no 24) fragments of ore were only discovered in blocks and not in associated outcrops. mineralization of the maškara vein type occurred inside a system of tensional fi ssures and joints of variable lengths, widths and depths. the ore occurrences strike mostly nnw–sse jurković i.b. et al.: cobalt, nickel, tungsten, cadmium, selenium, silver and gold-bearing mercurian tetrahedrite from the saski rad... geologia croatica 227 and dips towards the ene with very different angles. the other extensive system, 3.5 km long, has been registered between the vrbas and desna rivers (n–s strike, dip towards the e). in higher levels of the ore deposits, barite predominates over subordinate hg-tetrahedrite, whereas in the lower levels siderite and hg-tetrahedrite (± quartz) predominate. within the geological column, a vertical zonation of the whole silurian–devonian complex was also observed. in the lower parts of the complex, siderite with subordinate barite and quartz are common, whereas in the higher parts, barite with subordinate siderite and tetrahedrite are common. the relationships between tetrahedrite, barite and siderite in maškara-saski rad vein described by katzer (1907) are shown in fig 2. 3. the main genetic and paragenetic types of mineral occurrences established in the mbsm and se bosnia the following main genetic and paragenetic types of mineral occurrences have been established in the mbsm and se bosnia: ia) the oldest nonmetallic occurrences are numerous variscan synorogenic and postorogenic sterile, monomineralic quartz veins and irregular quartz bodies located in the busovača, fojnica, kiseljak, and kreševo area (katzer, 1926; jurković, 1956; hrvatović, 1996). ib) the oldest metallic ore deposits, mačje jame iron ore deposits (jurković, 1956) and vranjska rijeka (jurković and hrvatović, unpublished) are located west of the town of busovača. these deposits are formed at t = 350– 400°c and p = 3–5 kbars (majer et al., 1991). the main minerals are siderite and ankerite (50–90 wt.%), with magnetite, haematite, albite, ti-oxides (10–30 wt.%). this fi rst phase is followed by a very subordinate pneumatolytic phase with quartz, pyrite, arsenopyrite (5–10 wt.%) associated with cassiterite (0.024 wt.%), and ferberite (0.012 wt.%). the mineralization in these two ore deposits is completed by a weak hydrothermal phase which consists of cu, zn, fe, as, bi (cosalite), sb-sulphides and sulphosalts. the crude ore contains 10 ppm ag, 0.33 ppm au, 0.7 wt.% cu, 0.6 wt.% as, 15 to >230 ppm bi and to 25 ppm se. the copper-bearing sinjakovo siderite deposit, located west of the town of jajce, also belongs to this genetic type (vasiljević, 1972). bartalsky (1991) discovered an almost identical genetic and paragenetic type of ore in the gemericum (slovakia). radvanec et al. (2004) consider that this is the oldest slovakian deposit generated at t = 330–380°c and p = 2–4 kbars. ii) the vrtlasce ore deposit is a small, but paragenetically very interesting ore type, located east of the town of fojnica. siderite, ankerite and subordinate albite are the main minerals, but the pneumatolytic phase with cassiterite, stannite and molybdenite is clearly noticeable (jurković, 1956; 1958). the hydrothermal phase with 0.02 wt.% cu, 2.2 wt.% pb, and 5.0 wt.% zn is very well developed. this deposit having >300 ppm ag was a very good supply of silver for the saxon miners in the middle ages. due to the reduction of bi and se, the content of gold was only 0.07 g/t. the silver bearing minerals were galena, boulangerite and other pb-antimonides. iii) numerous quartz veins (the longest of which is 1500 m) with silver-bearing sphalerite, antimonite, and pbantimonides as the main ore minerals, comprise the čemernica genetic type, located northwest, northeast and east of the town of fojnica (katzer, 1926; jurković, 1956, 1962; jurković et al., 1999). entire ore reserves (300.000 t) contain 5.9 wt.% zn, 4.0 wt.% sb, and 114 g/t ag. the au content is only 0.01 g/t, bi and se occur in trace amounts. in the čemernica “main vein”, ramović (1956) discovered ferberite with 74 wt.% wo4; 18 wt.% fe and 6.2 wt.% mn. iv) the bakovići gold-bearing pyrite veins with 10–20 wt.% sio2, 5–10 wt.% of mn-siderite and 50–75 wt.% of gold-bearing pyrite are the richest gold deposits in bosnia and herzegovina. the average gold content in the bakovići ore deposit is 21 g/t au and 13 g/t ag. the source of gold in this deposit is presently unknown (jurković, 1995). v) barite ± siderite veins and irregular replacement bodies with 1–10 (max.15 wt.%) of fe, cu, zn, pb, and sb sulphides and sulphosalts characterized by positive δ34scdt (0.0 to +5‰), are predominantly located in se bosnia, rarely in the mbsm (ramović, 1957, 1976; jeremić, 1963; kule nović, 1987; jurković et al., 2010). an identical morphologic and paragenetic type of polysulphide-bearing barite deposits has been found in the petrova and trgovska gora mts. in croatia (jurković, 1958) and in nw bosnia (šiftar, 1988, 1990) but only sporadically in the mbsm (jurković, 1956; jurković et al., 2010). small quantities of sb-tetrahedrite do not contain mercury in the crystal lattice, being also characterized by a positive δ34scdt. this type of barite deposit with the polysulphide group of ore mine rals, has been formed at moderate temperatures of 140°c as determinated by the fl uid inclusion studies of blečić (1983). figure 2: the relationships between tetrahedrite, barite and siderite in maškara-saski rad vein described by katzer (1907). siderite gangue contains richer tetrahedrite masses then the barite gangue. captions: p = phyllite, s = siderite; b = barite; t = tetrahedrite; q = quartz. geologia croatica 64/3geologia croatica 228 vi) the youngest group of ore deposits consists exclusively of two morphologic groups of hg-tetrahedrite-bearing barite deposits. the fi rst morphologic type are quartz-siderite-barite vein deposits; the maškara-saski rad type, rich in hg-tetrahedrite. barite crude ore contains 10–16 wt.% of hg-tetrahedrite, whereas siderite crude ore is richer and contains 20–65 wt.% of hg-tetrahedrite (katzer, 1907). all other ore minerals are only accessories or occur in microscopic dimensions. the second morphological type, the kreševo type, are barite ± calcite ± quartz irregular replacement bodies with a very low content of hg-tetrahedrite (traces or 1 to 5 wt.%) and high temperature, octahedral fl uorite. all other microscopically established minor minerals are only accessories (jurković, 1987). numerous fl uid inclusion studies revealed a strongly increased homogenisation temperature of 230–330°c (palinkaš & jurković, 1994; jurković & palinkaš, 1996; jurković & palinkaš, 2002; jurković et al., 2002). in both types of hg-tetrahedrite deposits, tetrahedrite is characterized by a strongly negative δ34scdt. the position of the main genetic and paragenetic types of mineral occurrences are shown in fig. 3. 4. analytical methods numerous thick opaque polished sections of the tetrahedrite samples were studied using refl ected polarized light. thinsections of barite and siderite samples were examined using transmitted polarized light. the information obtained enabled separation of the fresh and weathered samples. selected samples were crushed, hand-picked under binocular microscope and powdered in an agate mortar for chemical analysis. a relatively high se content (>100 ppm) was determined for the fi rst time in the fresh hg-tetrahedrite of the saski rad deposit in the mbsm. this led to similar analysis of the weathered hg-tetrahedrite of saski rad deposit in order to confi rm a similar high se content of hg-tetrahedrite as a typical characteristic of this deposit. major and trace elements were analysed by inductively coupled plasma (icp) mass spectrometry – in acme analytical laboratories, (vancouver) ltd. in canada. sulphur and oxygen stable isotope compositions were determined at the stable isotope laboratory of the university of lausanne, using the finnigan mat facility. the saski rad no 7 tetrahedrite sample has been analyzed by atomic absorption spectrometry (aas) and icp– aes, after br2hcl digestion, in the croatian geological institute in zagreb (jurković et al., 1997), and saski rad no 8 tetrahedrite sample by pixe method with scanning proton microprobe in the institute rudjer bošković in zagreb (jurković et al., 1997). 5. results 5.1. analytical results of the fresh hg-tetrahedrite (sas–tet sample) results of quantitative chemical analyses of hg-tetrahedrite samples from the saski rad deposit, are presented in table 2. the fi rst two analyses, performed in 1994 and 1997, contain only the major constituent elements (cu, fe, mn, zn, hg, ag, sb, as, bi, te, s and au), whereas minor and trace constituents (ni, co, w, cd and se) as defi ned by duda & rejl (1987) were not analysed. however, the third analysis shown in table 2 results from the present work and contains major, minor and figure 3: positions of the most important genetic and paragenetic types of ore deposits in the mbsm area. geologycal map after sofilj & živanović (1979). legend: q-quaternary, m-miocene, k-cretaceous, j-jurassic, t1,2-lower and middle triassic, p3-upper permian, c1-lower carboniferous, d-devonian, s-pre-devonian metamorphic rocks, lll-triasic diorite, minor gabbro, albite syenite, albite granite; nnn-middle triassic volcanic rocks (keratophyre, ande site, dacite); +++ – upper palaeozoic rhyolites, metarhyolites. positions of the ore deposits after jurković et al (1994). typ es of ore deposits: � bu so vača type; � mačje jame type; � vranjska rijeka ty pe; � vrtlasce type;� čemernica type; � bakovići type; � se bosnia type; � maškara – saski rad type; � kreševo type; � vilenica type. jurković i.b. et al.: cobalt, nickel, tungsten, cadmium, selenium, silver and gold-bearing mercurian tetrahedrite from the saski rad... geologia croatica 229 trace elements, along with the rare earth elements (ree). this analysis represents the sas–tet hg-tetrahedrite sample. according to the analysis of the sas-tet sample, the studied tetrahedrite represents a cu-sb-s tetrahedrite, in which cu is isomorphically replaced by fe (5.70 wt.%), hg (3.81 wt.%), zn (0.225 wt.%) and ag (>0.03 wt.%) and also by minor elements (71 ppm ni, 113 ppm co, 20 ppm w and 27 ppm cd). additionally, sb is replaced by as (5.02%) and bi (0.25 %), whereas s is replaced by se (>100 ppm). this represents the fi rst discovery of selenium in the mbsm and se bosnia tetrahedrite samples. au (11 ppm) is present in microcavities table 2: quantitative chemical analyses of hg-tetrahedrites from the saski rad deposit. abbrevations: (1) analysis performed by jurković et al. (1994); (2) analysis performed by jurković et al. (1997); (3) analysis performed for the present work (sas–tet sample); m.a. – mechanical admixtures; tr-el. – trace elements, mdl – method detection limit. the diff erence between 97.5% and 100% is attributed to unanalysed o2 and h2o+. tetrahedrite tetrahedrite tetrahedrite jurković et al., 1994 jurković et al., 1997 sas–tet this work main element main element mdl mdl ree mdl tr. el. mdl admixture in tetrah. wt. % wt. % wt. % ppm wt. % ppm ppm ppm ppm % cu 38.290 41.770 cu 39.8100 0.001 la 9.30 0.10 cr 20.0 10.00 baso4 0.0467 fe 5.070 5.030 fe 5.7010 0.010 ce 0.60 0.10 mo 7.3 1.00 srso4 0.0129 zn 0.290 0.460 zn 0.2249 0.010 pr 0.05 0.02 tl 91.9 0.10 caco3 0.3496 mn n.a. n.a. mn <0.0100 n.a. 0.010 nd <0.30 0.30 cs 0.2 0.10 mgco3 0.0347 hg 2.820 4.060 hg 3.8120 0.001 sm <0.05 0.05 rb 1.2 0.10 total 0.4439 ag 0.140 0.149 ag >0.0300 2.00 eu <0.02 0.02 u 0.1 0.10 ni n.a. n.a. ni 0.0071 0.10 gd 0.07 0.05 v 0.9 8.00 co n.a. n.a. co 0.0113 0.20 tb 0.01 0.01 zr 0.6 0.10 w n.a. n.a. w 0.0020 0.50 dy 0.08 0.05 y 0.3 0.10 cd n.a. n.a. cd 0.0027 0.10 ho <0.02 0.02 total 122.5 sb 21.160 16.830 sb 19.0300 0.001 er 0.05 0.03 as 4.010 5.840 as 5.0200 0.010 tm <0.01 0.01 bi 0.232 0.247 bi 0.2509 0.010 yb <0.05 0.05 te n.a. n.a. te n.a. n.a. – lu <0.01 0.01 s 25.440 23.340 s 22.6315 0.005 total 10.16 se n.a. n.a. se >0.0100 0.50 co3 2n.a. n.a. co3 20.5151 au 0.00218 n.a. au (ppb) 0.00110 0.50* m.a. n.a. n.a. m.a. 0.4439 tr-el. n.a. n.a. tr-el. 0.0122 ree n.a. n.a. ree 0.0010 total 97.450 97.730 total 97.5170 cation proportion cu+ag+hg 0.61792 0.67894 fe+zn 0.09522 0.09772 sb+ag+bi 0.22843 0.21736 s 0.79341 0.72792 me2+ : me3+ : s 3.12:1.3:3.47 3.57:1.3:3.5 table 3: sulphur isotope composition of six mercurian tetrahedrites from the saski rad deposit. sample δ34scdt publication ‰ sas-41. no 102/a –9.50 jurković et al., 1994 saski rad no 7 –10.69 jurković et al., 1997 saski rad. no 8 –9.68 jurković et al., 1997 sas-41.no 102/b –9.90 this work s-radt –10.30 this work sas-tet –10.60 this work geologia croatica 64/3geologia croatica 230 and fi ssures of tetrahedrite. only 9 trace elements (cr, mo, tl, cs, rb, u, v, zr and y), among the 31 analysed, have been detected, accounting for 122.5 ppm in total. among them tl is the most abundant (91.9 ppm; accounting for 75% of the total). in the other analysed tetrahedrite samples from the mbsm, tl was not detected. the ree values of the studied hg-tetrahedrite are very low (10.16 ppm in total, table 2). the δ34scdt values of this hg-tetrahedrite equal –10.60‰. there are six hg-tetrahedrite samples from the saski rad deposit (table 3), which have already been analysed for δ34scdt values (three in this work). these values, ranging from –9.50‰ to –10.69‰ (average: –10.09‰), are in accordance with 18 other values obtained from 18 different hg-tetrahedrite samples over the whole mid-bosnian schist mts. (jurković et al., 1997), which range from –5.50‰ to –15.40‰ (average: –10.40‰). 5.2. analytical results of weathered hg-tetrahedrite (sas-41 sample) results of quantitative chemical analysis of one weathered hg-tetrahedrite, grown inside the oxydised siderite from the saski rad deposit, are presented in table 4. the elements v (15.00 ppm), y (2.40 ppm), rb (0.80 ppm), zr (0.50 ppm) and u (0.40 ppm) have values barely above method determination limit (mdl). all other trace elements have been not detected. the studied weathered hg-tetrahedrite contains the following microconstituents: ni (70 ppm), ag (>300 ppm), co (90 ppm), w (50 ppm), cd (20 ppm) and se (70 ppm), whereas au (9175 ppb) is present in cavities and fi ssures of tetrahedrite. the discovery of selenium in the fresh tetrahedrite (>100 ppm se) and also in the weathered tetrahedrite (70 ppm se) from the saski rad ore deposit defi nitely confi rms the presence of selenium as a constitutive trace element in the tetrahedrite crystal lattice of the mbsm region. the ree values of the studied sample are very low (9.96 ppm in total), similar to the other hg-tetrahedrites. gangue minerals (barite, calcite and dolomite) are present and account for 0.688 wt.%. 5.3. analytical results of the barite (s-rad sample) analysis of the barite, which occurs in paragenesis with tetrahedrite in the rad ore deposit is presented in table 5. table 4: quantitative chemical analysis of the weathered hg-tetrahedrite sample (sas-41) from the saski rad deposit. abbrevations: m.a. – mechanical admixtures; tr-el. – trace elements. weathered tetrahedrite sas-41 this work major elements ree trace elements admixture wt.% mdl % ppm mdl ppm ppm mdl ppm % cu 30.380 0.001 la 7.00 0.10 mo <1.0 0.1 baso4 0.141 fe 11.040 0.010 ce 0.90 0.10 tl <0.1 srso4 0.020 zn 0.240 0.010 pr 0.08 0.02 be <1.0 1.0 caco3 0.225 mn n.a. nd <0.30 0.30 cs <0.1 0.1 mgco3 0.312 hg 2.867 0.001 sm 0.12 0.05 ga 0.5 0.5 feco3 14.082 ag >0.030 0.002 eu 0.04 0.02 hf <0.1 0.1 mnco3 1.025 ni 0.007 0.001 gd 0.28 0.05 nb <1.0 0.1 pbs 0.440 co 0.009 0.001 tb 0.07 0.01 rb 0.8 0.1 total 16.245 w 0.005 0.00005 dy 0.46 0.05 sn <1.0 1.0 cd 0.002 0.001 ho 0.10 0.02 ta <0.1 0.1 sb 13.170 0.001 er 0.42 0.03 th <0.2 0.2 as 3.770 0.010 tm 0.07 0.01 u 0.4 0.1 bi 0.190 0.010 yb 0.53 0.05 v 15.0 8.0 te n.a. lu 0.09 0.01 zr 0.6 0.1 s 13.781 0.050 total 10.16 y 2.4 0.1 se 0.007 0.00005 cr <10.0 10.0 au* 9175 0.5 ppb na,k, al <100.0 loi 8.666 -5.1 total 19.7 m.a. 16.245 tr–el 0.002 ree 0.001 total 100.413 jurković i.b. et al.: cobalt, nickel, tungsten, cadmium, selenium, silver and gold-bearing mercurian tetrahedrite from the saski rad... geologia croatica 231 in the fi rst group of trace elements, ranging from be to y, 4 elements (hf, rb, ta and y) were identifi ed accounting for only 12.20 ppm in total. the second group of trace elements (mo to se) contains, among others, cu (68.40 ppm), sb (21.10 ppm), as (5.40 ppm), hg (5.25 ppm), zn (5.0 ppm), ag (1.0 ppm) and au (0.6 ppb), which are the major constituents of hg-tetrahedrite. microconstituent elements typical for hg-tetrahedrite have not been identifi ed in this barite sample. identical results were recorded in other studied barite samples taken from the various barite deposits throughout the mbsm. the analysed barite sample is characterised by its extremely low content of ree (6.61 ppm in total), which is similar to the other analysed samples of barite from the mbsm and se bosnia. the values for pr, nd and sm were below the mdl. the baso4 content of this sample is higher than 90.00 wt.% and its srso4 content is 6.24 wt.% (sr = 29781 ppm). 5.4. analytical results of siderite the content of the four major components (mol. and wt.%) of the siderite sample, representative of the maškara-saski rad vein system, analysed by jurković et al. (1994), are presented in table 6. molar composition refl ects a hydrothermal fl uid system characterised by heightened temperature. 5.5. analytical results of tetrahedrite and barite from neighbouring ore deposits for the purpose of the comparison, the sulphur and oxygen isotope compositions of hg-tetrahedrite and barite from the neighbouring cvrče village barite deposit (fig. 1.b) were also determined within the scope of this work. these results, together with isotopic compositions and srso4 content of barite from the djamuš brdo, crvče/zaganj and borova ravan barite deposits determinated by jurković et al. (1994) are presented in table 7. all analyzed δ34scdt values in tetrahedrites are negative (–1,20 to –10,69‰), whereas those in barites are positive (+15,10 to +18,48‰). 6. discussion 6.1. the problem of microconstituents in the tetrahedrite according to ramdohr (1986) 1/4 of copper places in tetrahedrite must be replaced by fe, zn, co, ni, ag and hg; arsenic and antimony by bi, sn, w, ge and te, and sulphur by selenium. duda & rejl (1987) defi ned only ni, co, w, cd and se as trace elements in tetrahedrite. johnson et al. (1988) and fott & hughes (2004) consider that copper can be replaced by fe, zn, mn, hg, cd, and ag; arsenic and antimony by bi and te; and sulphur by se. they consider that the structure of tetrahedrite must be analo guous to the structure of the mineral sodalite. the microconstituent elements can be inserted in tetrahedrite: (a) as micro-scale inclusions occupying defects in the structure; (b) as myrmekitic intergrowths of various fi neness, some of which originate through decomposition and (c) as exsolution textures. table 5: trace element and ree contents of the barite sample (s-rad) from the saski rad deposit. barite s-rad this work ree trace elements trace elements ppm mdl ppm ppm mdl ppm ppm mdl ppm la 1.40 0.10 be <1.00 1.00 mo 0.20 0.10 ce 0.10 0.10 co <0.20 0.20 cu 68.40 0.10 pr <0.02 0.02 cs <0.10 0.10 pb 1.40 0.10 nd <0.30 0.30 ga <0.50 0.50 zn 5.00 1.00 sm <0.05 0.05 hf 3.10 0.10 ni 0.20 0.10 eu 1.65 0.02 nb <0.10 0.10 as 5.40 0.50 gd 2.04 0.05 rb 0.30 0.10 cd <0.10 0.10 tb 0.12 0.01 sn <1.00 1.00 sb 21.10 0.10 dy 0.61 0.05 ta 7.50 0.10 bi <0.10 0.10 ho 0.18 0.02 th <0.20 0.20 ag 1.00 0.10 er 0.32 0.03 u <0.10 0.10 au* (ppb) 0.6 0.50 tm 0.03 0.01 v <8.00 8.00 hg 5.25 0.01 yb 0.15 0.05 w <0.50 0.50 tl <0.10 0.10 lu 0.01 0.01 zr <0.10 0.10 se <0.50 0.50 total 6.61 y 1.30 0.10 total 107.95 baso4 > 93.00 % total 12.20 sr 29781 srso4 6.24 % table 6: the content of the four major components of the siderite sample from the saski rad deposit (jurković et al., 1994). components wt % mol % feco3 81.23 74.39 caco3 9.52 10.18 mgco3 6.59 12.22 mnco3 2.66 2.47 total 100.00 99.26 table 7: sulphur and oxygen isotope compositions of hg-tetrahedrites and barites and srso4 content of barites from some barite deposits of the borova ravan area. captions: 1 – jurković et al., 1994; 2 – this paper. ore deposit tetrahedrite barite δ34scdt ‰ δ34scdt ‰ δ18osmow ‰ srso4 wt.% djamuš brdo1 –10.69 18.48 n.a. 2.70 cvrče / zaganj1 –9.68 17.11 n.a. 2.20 borova ravan1 n.a. 15.89 n.a. 2.50 cvrče village2 –1.20 15.10 18.10 n.a geologia croatica 64/3geologia croatica 232 according to ramdohr (1986) exsolutions in tetrahedrite are exceptionally rare (only bismuthinite and questioned “goldfi eldite”). the needles of bismuthinite (bi) oriented paralell to (111) (fig. 3) and discs and needles of bis muthinite (fig. 4) as exsolutions in tetrahedrite crystals (t) from the trošnik, fojnica deposit (mbsm) have been found by the fi rst author of this work during his postdoctoral study (1957) at the geological department of heidelberg university. these results have been confi rmed by professor ramdohr and published by jurković (1958). myrmekitic intergrowths of tetrahedrite (t) with one sulphide or sulphosalt (sl), the most probably ag-mineral according to optical properties, have been also documented by jurković (1958) and are shown in fig. 5. this texture most likely originated by decomposition of one rich silverbearing tetrahedrite containing 0.20 and 0.34 wt. % ag (jurković et al., 1997). according to our opinion, very often gold occurs mechanically inserted as micro-scale inclusions in tetrahedrite occuppying defect places in its structure. jurković (1958) took photomicrographs of gold also occurring as irregular masses of microscopic dimension (fig. 6). 6.2. distribution of the most important tetrahedrite microconstituents as trace elements in the ore deposits located in the mbsm and se bosnian areas the distribution of co, ni, sn, w, ag, au, hg, bi and se in the seven main genetic types of ore deposits (chapter 3) is presented in the table 8. cobalt is the most abundant element in the oldest phase (mačje jame, 78 ppm) and in the youngest phase of mineralisation (maškara-saski rad veins, 113 ppm). one unindentifi ed mineral with optical characteristics very similar to a figure 4: the photomicrograph of the needles of bismuthinite (bi) oriented paralell to (111) as exsolutions in tetrahedrite crystals (t) from the trošnik, fojnica deposit. magnifi cation: 300x. figure 5: the photomicrograph of the discs and needles of bismuthinite (bi) as exsolutions in tetrahedrite crystals (t) from the trošnik, fojnica deposit. magnifi cation: 450x. figure 6: the photomicrograph of myrmekitic intergrowths of tetrahedrite (t) with one sulphide or sulphosalt (sl) from the trošnik, fojnica deposit. magnifi cation: 300x. figure 7: the photomicrograph of gold (au) occurring as small, irregular masses in tetrahedrite (t) from the maškara-saski rad gold-bearing tetrahedrite. magnifi cation: 300x. jurković i.b. et al.: cobalt, nickel, tungsten, cadmium, selenium, silver and gold-bearing mercurian tetrahedrite from the saski rad... geologia croatica 233 co-ni-arsenide was discovered using a polarised microscope, but only from the mačje jame deposit. nickel is most abundant in the mačje jame deposit (105 ppm) then in the vrtlasce deposit (78 ppm) and in the maškara-saski rad tetrahedrite veins (71 ppm). tin has been found optically as cassiterite and stannite minerals by jurković (1956, 1958a) in the vrtlasce deposit (average 429 ppm sn; maximal 900 ppm) and in the mačje jame (115 ppm sn). jurković & hrvatović (manuscript) found tin in the vranjska rijeka deposit. these three ore deposits are characterized by a well developed pneumatolytic phase. in the hydrothermal phase (hg-tetrahedrite) tin is very rare and hardly measurable. tungsten as the mineral ferberite (fe,mn)wo4 was discovered by ramović (1956), in the silver-bearing sphalerite-antimonite quartz vein named “main vein” and “nw čemernica” veins (w = >100 ppm). small contents of w we found in the mačje jame deposit (26 ppm) and in the maškara-saski rad hg-tetrahedrite veins (20 ppm). the majority of tungsten was consumed earlier by formation of mineral wolframite. bismuth and selenium are closely genetically related. their presence was fi rst observed in the mačje jame deposit (bi = 15 and se = 14 ppm), but they are most abundant in the vranjska rijeka deposit (230 ppm bi and 20 ppm se), as the minerals cosalite and elemental bismuth (jurković & hrvatović, in press). the vranjska rijeka deposit contains 0.33 g/t of gold, the vrtlasce deposit contains 0.07 g/t and there is less in the mačje jame deposit at 0.01 g/t. the occurrence of bi and se simultaneously with gold in these three deposits indicates their clear positive correlation. the best positive correlation between bi, se and au has been established in the hg-tetrahedrite deposits, maškarasaski rad and kreševo types. the element bi, having usually microelement status, becomes a very important major element (0.20–0.25 wt.%; max. 0.58 wt.%), whereas the abundance of se exceedes 100 ppm. tetrahedrites with such contents of bi and se, contain 8 to 62 g/t of au and between 300 ppm and 0.34 wt.% of ag (jurković et al., 1997). in hg-tetrahedrite, gold is in pronounced positive correlation with mercury which in the hg-tetrahedrite also becomes a major element (on average 3.0 wt.%) for the fi rst time. in the earlier mineralization phases, mercury was only a trace element. the occurrence of scarce cinnabar in the čemernica deposit is an exception, but in our opinion, this phenomenon is only a younger overprint. silver is characterized by a positive correlation with pb–sb sulphides and sulphosalts in the vrtlasce and čemernica deposits. in the middle ages, these two groups of silverbearing deposits were rich suppliers of silver ore for the saxon miners. the second bearers of silver are small, but numerous polymetallic barite ± siderite ± calcite ± quartz veins and replacement bodies, and are best developed in se bosnia. they are rare in the mbsm. ag is linked with fe, cu, zn, pb, and sb sulphides and sulphosalts, particularly with pbs and pbantimonides. the silver content is moderate (some tenths of a gram/t) and gold only occurs as a trace element. the third, youngest silver mineralization phase is genetically related to the occurrences of hg-bi-tetrahedrite in the monosulphide barite-siderite maškara-saski rad veins, and in the barite ± fl uorite replacement bodies of the kreševo type. these deposits contain hg-tetrahedrite, in which the ag content ranges between 300 ppm and 3400 g/t, whereas its au content varies from 8 to 62 g/t. the bakovići deposit also has a high content of gold (21 g/t) but only 13 g/t ag. cadmium isomorphically supstitutes zinc in the crystal lattice of sphalerite and zinc in the hg-tetrahedrite. tellurium in the hg-tetrahedrite from the mbsm has not, so far, been investigated by chemical analyses. optical investigations of polished sections of maškara hg-tetrahedrites under polarized microscope revealed some minute minerals, with optical characteristics very similar to au-telluride (jurković, 1960). this suggests that there should be a positive correlation between gold and tellurium. thalium with an increased content of 91.9 ppm has been only been discovered in one out of more than fi fty analysed samples. comparison of the microconstituents of studied hg-tetrahedrite from the saski rad vein deposit, with those of the hg-tetrahedrite samples taken from the duboki vagan detable 8: the distribution of co, ni, sn, w, ag, au, hg, bi and se in the seven main genetic types of ore deposits. ore types co ppm ni ppm sn ppm w ppm ag ppm au ppb hg ppm bi ppm se ppm rhy-kreševo 8.0 8.0 3.0 3.00 <0.1 n.a. 0.04 0.1 <0.5 rhy-busovača 6.0 <20.0 2.0 n.a. <0.5 n.a. n.a. n.a. n.a. mačje jame 77.7 104.7 114.7 25.80 1.3 n.a. 0.32 15.4 13.5 vranjska rij. 25.3 7.7 44.1 1.10 10.3 0.33 2.02 >229.4 20.0 vrtlasce 13.8 77.7 428.7 0.50 >52.9 0.07 28.00 >36.1 29.9 čemernica 1.0 n.a. 4.00 >100.00 153.2 0.01 436.8 10.0 n.a. bakovići 1.0 3.0 4.00 n.a. 13.0 21.00 n.a. 10.0 n.a. seb–a 4.6 29.7 <1.0 0.70 20 50 tr. 0.7 0.3 <0.5 seb–b 1.0 16.4 <1.0 0.08 0.04 0.30 0.46 <0.1 <0.5 saski rad 113.1 71.3 <1.0 20.00 >300.0 11.00 3.81% 0.25% >100.0 geologia croatica 64/3geologia croatica 234 posit (kreševo, mbsm) and the brixlegg deposit (tyrol, austria) is presented in table 8. there is an interesting correspondence in the content of se between saski rad and brixlegg deposits. the au content in the saski rad and duboki vagan tetrahedrites is several times higher than that of brixlegg tetrahedrite. furthermore, the saski rad and duboki vagan tetrahedrite have higher ni and bi content compared to the brixlegg tetrahedrite. however, the brixlegg tetrahedrite contains more co and cd than the saski rad tetrahedrite. 6.3. problem of lanthanides (ree) table 10 compares the total ree content, and values of the three dominant lanthanides (la, ce, and nd), in the (meta)rhyolite and keratophyre of the kreševo (kre) and busovača (bus) regions, with the ree contents of some important ore deposits in the mbsm and se bosnia. this arose from the suspicion that the oldest mačje jame and vranjska rijeka iron deposits may have a direct genetic connection with metamorphogenic fl uids generated during progressive and retrograde variscan (hercynian) metamorphism. the total ree and the contents of the dominant lanthanides (la,ce,nd) in rhyolite, keratophyre and the oldest iron deposits of mačje jame and vranjska rijeka is very high and almost the same, indicating a direct genetic link. rash reduction of total ree content during the subsequent phase of mineralization (vrtlasce deposit) is the result of crystallization of some lanthanide minerals in the earlier phase. these were most probably minerals of the bastnaesite group, as described by radvanec et al. (2004) in the similar slovakian ore deposit. only partial analytical data is available for the čemernica type deposit and the later bakovići ore type mineralisation phase, and therefore they could not be included in table 10. numerous analytical values have been obtained from the fi fth phase of mineralization. the highest content of total ree characterizes the siderite from se bosnia (33.0 ppm). lower contents have been found in siderite from the trošnik ore deposit (15.6 ppm), in the hg-tetrahedrite from the maškara-saski rad deposit (9.2 ppm) and in barite from the maškara-saski rad deposit (8.4 ppm), whereas barite from the se bosnia contains only 5.1 ppm of total ree. fluorite from the dubrava (kreševo) ore deposit is the mineral containing the least ree. its two analyses contain 0.427 and 0.406 ppm of total ree. these fl uorites belong to the latest phase of mineralisation in the mbsm. analyses of fl uorites were performed by inaa facilities in the institute for petrology and geochemistry, karlsruhe university (palinkaš & jurković, 1994). the evidence suggests a successive decrease of total ree contents, not only because of the formation of new ree minerals, but also due to insertion of ree in the vacant defect places of the crystal lattices of other minerals, especially siderite, ankerite, barite and tetrahedrite. evidence suggests that mixed hydrothermal fl uids played a specifi c role in this process during the last mineralization phase. the development of ree from the oldest to the youngest ore deposits indicates gradual reestablishment of a uniform and unique hydrothermal system in the mbsm area. 6.4. composition of feco3, caco3, mgco3 and mnco3 isomorphic components of siderite in the diff erent genetic and paragenetic types of ore deposits in the mbsm and se bosnia table 11 shows six siderite chemical analyses belonging to the six most important genetic and paragenetic ore types from the mbsm deposits: mačje jame, vranjska rijeka, vrtlasce, trošnik, maškara-saski rad and bakovići-čemertable 10: the contents of the total ree and the values of the three dominant lanthanides (la, ce, and nd) in the (meta)-rhyolite and keratophyre of the kreševo (kre) and busovača (bus) regions compared with those of some important ore deposits in the mbsm and se bosnia. rhyolite-keratophyre ore occurrences and deposits in the mbsm and se bosnia localities kreševo fojnica busovača vitez mačje jame vranjska rijeka vrtlasce fojnica seb–a sd–ba trošnik fojnica saski r. tetrah. saski r. barite seb–b barite kreševo fl uorite ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm σree 183.1 159.5 216.5 158.8 59.5 33.0 15.6 9.15 8.4 5.14 0.416 la 38.0 29.4 33.1 36.8 9.8 5.9 2.9 8.19 1.8 1.30 0.026 ce 76.8 64.8 74.6 60.1 23.7 4.9 5.5 0.64 0.3 0.24 <mdl nd 30.0 28.4 26.6 30.3 9.6 6.7 3.0 <0.30 <0.3 <0.30 <mdl table 9: diff erences in the content of some microconstituents in the hg-tetrahedrite crystal lattice between the duboki vagan (kreševo), saski rad (gornji vakuf) and brixlegg (tyrol, austria) barite deposits. the tetrahedrite sample from the brixlegg deposit was gifted by prof. w. prochaska, university leoben. dubrave saski rad brixlegg d–vagt sas–tet sas–41 brx–1 ni 266.2 71.0 70.0 <0.1 co 63.5 113.0 90.0 234.4 cd 313.6 27.0 20.0 160.5 w <0.5 20.0 5.0 6.7 sn <1.0 <1.0 <1.0 1.0 bi 1466.0 2500.0 1613.0 909.1 se <0.5 >100.0 72.0 >100.0 au 38.96 11.0 9.0 2.3 σ ree 15.03 10.16 9.96 17.43 jurković i.b. et al.: cobalt, nickel, tungsten, cadmium, selenium, silver and gold-bearing mercurian tetrahedrite from the saski rad... geologia croatica 235 nica. the paragenesis and some pt conditions of these deposits are described in chapter 3. table 11 demonstrates the clear interdependence of the composition of fe-carbonates and pt conditions during their genesis. 7. conclusions a) both fresh and weathered hg-tetrahedrite samples from the saski rad deposit have been examined concerning their microconstituents. w (20 ppm) and se (>100 ppm) have been detected for the fi rst time in the mbsm hg-tetrahedrite. there is an interesting correlation of the se content between the saski rad and brixlegg deposits. the au content of the saski rad hg-tetrahedrite is relatively high (11 ppm), four times lower than in the duboki vagan tetrahedrite, but four times higher than in the brixlegg hg-tetrahedrite. b) the low content of total ree (10 ppm) and strong negative δ34scdt values (average: –10.09‰) in the hg-tetrahedrite samples of the saski rad vein deposit are in accordance with 18 other previously analysed hg-tetrahedrite samples from the whole of the mid-bosnian schist mts. c) the quantitative relationship of the main constituents in the studied tetrahedrite is very similar to that in the tetrahedrite of the maškara deposit, confi rming the earlier assumption that the saski rad vein deposit represents the broken part of the maškara ore vein. d) the co, ni, sn, w, ag, au, hg, bi and se distribution in the seven most important paragenetic types of the mbsm and se bosnia ore deposits is signifi cant in several ways. optical studies suggest that co and ni, are most probably present as co-ni arsenides in the oldest iron deposits (mačje jame and vranjska rijeka), and also occur as microconstituents in hg-tetrahedrite. sn is completely consumed in the pneumatolytic-hydrothermal pb, zn and cu sulphide deposits as cassiterite and stannite. the fi rst sn occurrence is detected in the mačje jame deposit. w, as the mineral ferberite, was found in the silver-bearing čemernica sphaleriteantimonite deposit. bi with 230 ppm and se with 20 ppm drew attention to the fi rst gold (0.33 ppm) presence in the vranjska rijeka copper (0.7 % cu) deposit. the second very strong occurrence of bi (with 0.25–0.58 wt.%) and se (with >100 ppm) is observed in the last hydrothermal hg-tetrahedrite-bearing barite ± siderite phase. hg (average 3.07 wt.%), occurs in association with bi and se as a major constituent, whereas in all other deposits it is absent or present only as a trace element. there is a positive correlation between bi, se, hg and au, ag presence in studied ore deposits. e) a review of numerous previous scientifi c investigations of parageneses, isotope composition (c, o, s, sr, pb), fl uid inclusion, trace elements, and ree data analysis, suggests that the seven main paragenetic and genetic types of the mbsm and se bosnia ore deposits are generated dominantly from metamorphogenic fl uids. the important masses of (meta)-rhyolites and keratophyres are formed by anatexis, as evidenced by sr isotope data. palaeozoic protoliths, metamorphosed by several stages of variscan progressive and retrograde metamorphism, are the sources of hydrothermal fl uids. a similar opinion concerning the genesis of siderite ± barite deposits of rudnány (slovakia) was published by grecula et al. (1989); žak et al. (1950) and radvan ec et al. (2004). the most convincing evidence of the metamorphogenic origin of the hydrothermal fl uid is the strong similarity of total ree and the dominant la, ce and nd elements in the meta-rhyolite and their pellitic and psammitic metamorphosed protoliths on one hand and the oldest mačje jame and vranska rijeka iron ore deposits on the other (table 10). f) previous investigations of the mbsm and se bosnia ore deposits established unexpected contrasting parageneses that indicate several different hydrothermal fl uids and pt conditions. the best example is čemernica, an important rich silver-bearing deposit containing >150 g/t ag, only traces of au and >100 ppm w, in relation to the richest goldbearing pyrite deposit bakovići having 11 g/t au and only 13 g/t ag, but without w. deposits differ in salinity and in homogenization temperature (th). seb-a and seb-b barite-siderite deposits associated with polymetallic sulphides (the se bosnia type) are characterized by lower salinity (<10 wt.% nacl) and low th = 100–150°c. polymetallic monomineral barite-siderite ± octahedral fl uorite ore deposits, hg-tetrahedrite-bearing maškara-saski rad and kreševo types are characterized by high salinity (15–25 wt.% nacl) and high th = 230–330°c. g) the composition of feco3, caco3, mgco3 and mnco3 isomorphic components of sideritic gangue in the mbsm and se bosnia ore deposits are dependent upon pt conditions and the hydrothermal fl uid system. references bartalský, b. (1991): results of the study of vein mineralization in the rožňava ore fi eld – evidence for the metamorphic-hydrothermal genetic model.– unpublished csc thesis. geological survey of slovak republic, spišská nová ves (in slovak). blečić, a. (1983): ispitivanje izotopa sumpora, kisika i ugljika u antimonskim ležištima potkozara i kordići [examination of sulphur, oxygen and carbon isotope in antimony deposits of potkozara and kordići – in croatian].– in: ramović, e. (1991): metalogenija bosne i hercegovine [metallogeny of bosnia and herzegovina – in croatian].– unpubl. phd thesis, faculty of mining, geology and petroleum engineering, university of zagreb, 239 p. table 11: interdependence between the composition of siderite and its genetic ore type (pt conditions). mačje jame vranjska rijeka vrtlasce fojnica trošnik fojnica maškara saski rad bakovići čemernica wt. % wt. % wt. % wt. % wt. % wt. % feco3 62.53 70.13 71.75 74.39 81.23 86.66 caco3 8.78 3.55 15.75 12.89 9.52 1.43 mgco3 19.30 24.13 10.30 10.03 6.59 2.50 mnco3 9.40 2.20 2.02 2.69 2.66 10.10 ∑ 100.01 100.00 99.82 100.00 100.00 100.69 geologia croatica 64/3geologia croatica 236 cambel, b. & jarkovsky, j. (1985): rudnianske rudne pole-geochemicko-metalogeneticka charakterstika [the rudnany ore fi eldgeochemical-metallogenetic characteristics – in slovakian].– slovenska akademia vied, bratislava, 363 p. duda, r. & rejl, l. (1987): la grande encyclopedie des minéraux.– published by gründ, paris, 520 p. foit jr., f. f. & hughes, m. j. (2004): structural variations in mercurian tetrahedrite.– american mineralogist, 89, 159–163. frimmel, h.e. & papesh, w. (1990): sr, o, and c isotope study of the brixlegg barite deposit, tyrol (austria).– econ. geology, 85, 1162–1171. grecula, p., radvanec, m. & žák, k. (1989): metamorphic origin of hydrothermal ore fl uids of vein mineralization in the gemericum belt, western carpathians. 28th international geological congress, washington, usa. abstract volume, 584–585. gstrein, p. (1983): ueber mögliche umlagerungen fon fahlerzen im devonischen schwazer dolomit wie auch in der angrenzenden schwazer trias. oester. akad. d. wissench., 6.– in “ore mobilization in the alps and in se-europe”, leoben-wien, 65–74. hrvatović, h. (1996): strukturno-facijalna analiza sjeverozapadnog škriljavog gorja [structural and facies analysis of the mid-bosnian schist mts. – in bosnian].– unpubl. phd thesis, university of tuzla, 112 p. jeremić, m. (1963): metalogenija paleozojskih ležišta barita bosne [metallogeny of barite deposits in paleozoic of bosnia].– arhiv za tehnologiju, i, 1–2, tuzla, 1–59. johnson, n.e., craig, j.r. & rimstidt, j.d. (1988): crystal chemistry of tetrahedrite.– american mineralogist, 73, 389–397. jurković, i. (1951): prethodni izvještaj o planini vranici i njoj susjednih planina [preliminary report from vranica and adjacent mountains – in croatian].– arhiv inst. za geol. istraž., sarajevo. jurković, i. (1956): mineralne parageneze srednjobosanskog rudogorja s osobitim osvrtom na tetraedrite [mineral parageneses of the mid-bosnian ore mountains with particular respect on tetrahedrites – in croatian].– unpubl. phd theses, university of zagreb. 306 p. jurković, i. (1958): kasiterit, stanin i molibdenit u rudnoj pojavi vrtlasce kod klisca [cassiterite, stannite and molybdenite from the ore occurrence vrtlasce at klisac – in croatian].– geol. glasnik, 4, sarajevo, 1958, 309–320. jurković, i. (1960): quecksilberfahlerz vom mačkara gang bei gornji vakuf in bosnien.– neues jh.d.mineral., abh. 94, stuttgart, 539–558. jurković, i. (1962): parageneze rudnih pojava u oblasti čemernice kod fojnice [parageneses of ore occurrences in the area of čemernica near fojnica – in croatian].– geol. glasnik, 6, sarajevo 1962, 141–156. jurković, i. (1986): quantitative chemical and optical investigations of the tetrahedrite from barite-bearing deposit vidici on the northern slopes of the mountain međuvršje, south of the town of kreševo, bosnia.– geološki vjesnik, 39, 187–224. jurković, i. (1987): barite deposits on mount međuvršje south and south-east of the town of kreševo, bosnia.– geol. vjesnik, 40, 313–336. jurković, i. (1995): bakovići, the biggest gold deposit of bosnia and herzegovina.– rud. geol. naftni zbornik, 7, 1–15. jurković, i. & majer, v. (1954): rioliti (kremeni porfi ri) vranice planine i albitski riolit sinjakova u srednjobosanskom rudogorju [rhyolites-quartzporphyries – of the vranica mountain and albite rhyolite of sinjakovo in the mid-bosnian ore mountains – in croatian].– vjesnik zavoda za geološka i geofi zička istraživanja nr srbije, xi, beograd, 207–233. jurković, i. & palinkaš, l. (1996): late variscan, middle-upperpermian, post-variscan and triassic rifting related ore de posits in the northwestern and central dinarides.– proceeding of the annual meeting, unesco project no. 356, plate tectonic aspects of the alpine metallogeny in the carpatho-balkan region, sofi a, 1, 19–27. jurković, i. & miko, s. (1997): tetrahedrite from the dubravedugi dol barite deposit, kreševo, bosnia and herzegovina.– rudarsko-geološko-naftni zbornik, 9, 11–16. jurković, i. & palinkaš, l. (1999): sulphur isotope and fl uid inclusion data of barites from the dinarides.– sixth biennal meeting of sga and iagod.– mineral deposits, processes to processing, london, 1999. proceedings, balkema, pub., rotterdam, 1999, 45–49. jurković, i. & palinkaš, l. (2002): discrimination criteria for assignig ore deposits located in the dinaridic palaeozoic-triassic formations to variscan or alpidic metallogeny.– in: blundell, d.j, neubauer, f. & von quade, a. (eds.): the timming and location of major ore deposits in an orogen. geological society, london, special publications, 204, 229–245. jurković, i. & hrvatović, h. (in press): geology, petrology and geochemistry of the mačje jame and vranjska rijeka iron ore deposits, mid-bosnian schist mountains. jurković, i., šiftar, d. & pezdič, j. (1994): geology and geochemistry of the mineralization from the gornji vakuf, bosnia.– rudarsko-geološko-naftni zbornik, 6, 19–37. jurković, i., ramović, m. & zec, f. (1999): chemical and geochemical characteristics of the čemernica antimonite deposit in the mid-bosnian schist mountains.– rud.-geol.-nafnti zbornik, 11, 1–16. jurković, i., garašić, v. & hrvatović, h. (2010): geochemical characteristics of barite occurrences in the palaeozoic complex of south-eastern bosnia and their relationship to the barite deposits of the mid-bosnian schist mountains.– geol. croat., 63/2, 241– 258. jurković, i.b., garašić, v. & jurković, i.m. (2011): geochemical characteristics of mercurian tetrahedrite, barite and fl uorite from the duboki vagan, glumac and dubrave-dugi dol barite deposits, south of kreševo, mid-bosnian schist mts.– geol. croat., 64/1, 49–59. jurković, i., tončić-gregl, r., strmić, s. & šiftar, d. (2002): geology and geochemistry of the raštelica barite deposits southwest of sarajevo, bosnia and herzegovina.– rud.-geo.-naftni zbornik, 14, 37–46. jurković, i., palinkaš, l, šiftar, d., miko, s., jakšić, m. & pezdič, j. (1997): gechemical characteristics of mercurian tetrahedrites from the mid-bosnien schist mts.– the 4th sga meeting, finland. published by balkema, rotterdam, 829–833. katzer, f. (1907): die fahlerz– und quecksilbererzlagerstätten bosniens und der hercegovina.– berg-und hüttenmännisches jahrbuch der k. k. montanist. hochschulen zu leoben und pribram. lv 2, 121 p. katzer, f. (1926): geologie bosniens und der herzegovina.– erster band, i. u ii. hälfte, sarajevo. kubat, i., ramović, e., tomičević, d., pezdič, j. & dolen ec, t. (1979/80): results of the investigations of isotopic compositions of sulphur, oxygen, carbon and lead in some ore deposits and ore occurrences from bosnia and herzegovina (in bosnian).– geol. glasnik, 24–25, 61–84. kulenović, e. (1987): mineralizacije u paleozoiku jugoistočne bosne [mineralisation in palaeozoic of south-eastern bosnia – in serbian].– geol. glasnik, 31/31, 106–143. lukas, w. (1971): tektonisch-genetische untersuchung der fahlerz – lagerstätte am falkenstein bei schwaz (tirol).– n. jb. geol. paläont. mh, 47–63. jurković i.b. et al.: cobalt, nickel, tungsten, cadmium, selenium, silver and gold-bearing mercurian tetrahedrite from the saski rad... geologia croatica 237 majer, v. & garašić, v (2001): metarioliti vranice planine u paleozoiku središnje bosne [metarhyolites of vranica mountain in paleozoic of middle bosnia – in croatian].– rudarsko-geološkonaftni zbornik, 13, 9–14. majer, v., lugović, b. & trubelja, f. (1991): metamorphism of the midd-bosnian schist mountains – a preliminary investigation (in croatian).– radovi anubih, sarajevo, 87/13, 141–158. palinkaš, l. & jurković, i. (1994): lanthanide geochemistry and fluid inclusion peculiarities of the fluorite from the barite deposits south of kreševo (bosnia and herzegovina).– geol. croat., 47/1, 103–115. poech, f. (1900): l’industrie minérale de bosnie-herzègovine, wienne. radusinović, d. (1960): mineralni sastav koncentrata tečnih nanosa nekih bosanskih reka [mineral composition of some fl uvial placers in bosnia – in serbian].– unpubl. report, beograd, 31 p. radvanec, m., grecula, p. & žak, k. (2004): siderite mineralization of the gemericum superunit (western carpathians, slovakia): review and a revised genetic model.– ore geology reviews, 24 (2004), elsevier b. v., 267–298. ramdohr, p. (1986): the ore minerals and their intergrowths.– 2nd edition, vol. 2., pergamont press, international series in earth sciences volume 35, oxford. ramović, m. (1956): volframit iz čemernice kod fojnice, nr bih [wolframite from čemernica near fojnica, bosnia and herzegowina – in serbian].– tehnika, 11, 1651–1652 (rudarstvo i metalurgija 7 rm beograd) 243–244. ramović, m. (1957): pregled nalazišta minerala olova i cinka u bosni i hercegovini. [overview of mineral deposits of zinc and lead in bosnia and herzegovina – in serbian].– geol. glasnik, 3, sarajevo, 3–121. ramović, m. (1976): barit. mineralne sirovine bosne i hercegovine knjiga ii. ležišta nemetala [barite. mineral resources in bosnia and herzegovina. nemetallic ore deposits – in serbian].– geoin ženjering, sarajevo, 358– 379. ruecker, a. (1896): einiges über die goldvorkommen in bosnien.– monographische skizze, wien, 1–101. sofilj, j. & živanović, m. (1979): osnovna geološka karta m 1:100000 list prozor [geological map 1:100 000, sheet prozor].– savezni geološki zavod, beograd. sofilj, j., živanović, m. & pamić, j. (1980): tumač osnovne geološke karte list prozor [geological map 1:100000, geology of the prozor sheet – in croatian].– savezni geološki zavod, beo grad. šiftar, d. (1988): the chemical characteristics of barite from some bosnian deposits.– rudarsko–metalurški zbornik, ljubljana, 35, 75–89. šiftar, d. (1990): usporedba kemizma barita iz područja raštelice i kreševa u srednjobosanskom rudogorju [comparison of barite chemistry fom raštelica area and kreševo in mid–bosnian ore mountrains – in croatian].– geol. vjesnik, 43, 109–112. vasiljević, r. (1972): geologija i metalogenija paleozoika u području jezera i sinjakova kod jajca [geology and metalogeny of palaeozoic in jezero and sinjakovo area near jajce – in serbian].– unpubl. phd thesis, university of zagreb, 128 p. vesely, v. (1921): tetraedrit iz maškare u bosni [tetrahedrite from maškara in bosnia – in serbian].– glasnik hrvatskog prirodoslovnog društva, zagreb, 99 p. žak, k., radvanec, m., grecula, p. & bartalský, b. (1991): s, c, o, sr isotopes and a metamorphic-hydrothermal model of vein mineralization, gemeric unit, western carpathians.– mineralia slovaca, 23, 95–108 (in slovak with english abstract). živanović, m. (1972): geological structure and tectonic framework of the vranica mountain in central bosnia (in serbian).– unpubl. phd thesis, university of beograd. manuscript received november 24, 2010 revised manuscript accepted july 22, 2011 available online october 26, 2011 aish.indd 67 � ab stra ct mounding of the groundwater table beneath recharge sources is of concern as the raised water table approaches closely to near-surface facilities or features. the shape and height of the mound depend on several factors including the recharge rate, hydraulic conductivity and thickness of the aquifer. the objective of this paper is to evaluate the suitability of the study area for a rapid infi ltration system of treated wastewater effl uent without causing excessive mounding of the water table. a comparison was made between two methods used to estimate ground-water mounding: an analytical approach and a numerical approach. both approaches incorporate each of the saturated and the unsaturated zones. results predicted that after 1400 days of groundwater level simulation, the maximum rise of the mound was 18 m in the center of the infi ltration pond, and it was almost 17 m at the edges of the pond. as the natural average groundwater level was about 35 m deep in the area of the study, the groundwater mounding caused no problem on the groundwater level. thus, the planned infi ltration was feasible. keywords: artifi cial recharge, groundwater modeling, groundwater mounding simulation of groundwater mound resulting from proposed artifi cial recharge of treated sewage effl uent case study – gaza waste water treatment plant, palestine � adnan m. aish department of geology, faculty of science, al azhar university – gaza, p.o. box 1277 gaza, palestine; (a.aish@alazhar-gaza.edu) doi: 104154/gc.2010.04 geologia croatica 63/1 67–73 8 figs. zagreb 2010 geologia croaticageologia croatica 1. introduction artifi cial groundwater recharging is one of the most important means required to increase the natural supply of groundwater, and it is an augmentation of the natural movement of the surface water into underground formations by artifi cially changing natural conditions (choudhary, 2007). the timing and quantity of recharge reaching the water table has signifi cant consequences for water resources and for the movement of pollutants into groundwater (lee, 2006). two types of groundwater recharge are commonly used with reclaimed municipal wastewater: surface spreading or percolation, and direct aquifer injection. surface spreading is the oldest, simplest, and most widely applied method of artifi cial recharge. in surface spreading, recharge waters such as treated municipal wastewater percolate from spreading basins through the unsaturated soil and ground vadose zone. infi ltration basins methods are the most favored ones of recharge because they allow effi cient use of space and they require only simple maintenance. infi ltration rates are highest where soil and vegetation are undisturbed (todd, 1980). advantages of groundwater recharge by surface spreading include: (a) groundwater supplies may be replenished in the vicinity of metropolitan and agricultural areas where groundwater over-drafting is severe. (b) surface spreading provides the added benefi ts of the treatment effect of soils and transporting facilities of aquifers. direct subsurface recharge is achieved when water is placed directly into an aquifer. in the direct injection, highly treated reclaimed water is pumped directly into the groundwater zone, usually geologia croatica 63/1geologia croatica 68 for august. the average of the monthly minimum temperature for january is about 9.6 c° and 22.7 for august. the rainfall in the gaza strip gradually decreases from the north to the south. the values range from 410 mm/year in the north to 230 mm/year in the south. gaza topography is characterized by elongated ridges and depressions, dry streambeds and shifting sand dunes. the ridges and depressions generally extend ne–sw direction, parallel to the coastline. ridg es are narrow and consist primarily of pleistocene-holocen sandstone (locally named as kurkar) alternated with red brown layer (locally named as hamra). in the south these features tend to be covered by sand dunes. land surface elevations range from mean sea level to about 110 m above mean sea level. the soil in the gaza strip is composed main ly of three types, sands, clay and loess. the sandy soil is found along the coastline extending from south to outside the northern border of the strip, at the form of sand dunes. the thickness of sand fl uctuates from two meters to about 50 meters due to the hilly shape of the dunes. clay soil is found in the north eastern part of the gaza strip. loess soil is found around wadis, where the approximate thickness reaches about 25 to 30 m. (jury & gardner, 1991). the geology of coastal aquifer of the gaza strip consists of the pleistocene age kurkar group and recent (holocene age) sand dunes. the kurkar group consists of marine and aeolian calcareous sandstone (kurkar), reddish silty sandstone (hamra), silts, clays, unconsolidated sands and conglomerates (gvirtzman, 1984). regionally, the kurkar group is distributed in a belt parallel to the coastline, from haifa in the north to the sinai in the south. near the gaza strip, the belt extends about 15–20 km inland, where it unconformable overlies eocene age chalks and limestones (the eocene), or the miocenepliocene age saqiye group, a 400–1000 m thick aquitard beneath the gaza strip, consisting of a sequence of marls, marine shale’s and claystones. the kurkar group consists of complex sequence of coastal, near-shore and marine sedifi gu re 1: geographic location of the gaza strip with a schematic illustration of the recharge area and drilled boreholes. into a well-confi ned aquifer. groundwater recharge by direct injection is practiced: (a) where groundwater is deep or where the topography or existing land use makes surface spreading impractical or too expensive. (b) when direct injection is particularly effective in creating freshwater barriers in coastal aquifers against intrusion of saltwater. in arid climates where the practice of groundwater recharge is most imperative, recharge will occur through such means as dry riverbeds and spreading basins, and in most situations there will be an unsaturated zone between the surface and the aquifer (crook, 1990). pretreatment requirements for groundwater recharge vary considerably depending upon the purpose of groundwater recharge, sources of reclaimed waste water, recharge methods, location, and, more importantly, public acceptance. although the surface spreading method of groundwater recharge is in itself an effective form of wastewater treatment, some level of pretreatment must be provided to municipal wastewater before it can be used for groundwater recharge (asano, 1980). artifi cial recharge by spreading waters on a rectangular area is common in practice (walton, 1970). the variation of the water table beneath the recharged area is of practical interest. analytical solutions describing the variation of the water table of an infi nite aquifer in response to deep percolation have been reported by glover (1961), marmion (1962), marino (1967, 1974), hantush (1967), bianchi & muckel (1970), rao & sarma (1983), and latinopoulos (1986). most of these solutions are based on the assumption of a constant rate of recharge applied continuously or periodically. it is a common assumption to all these solutions that percolation moves vertically downward until it joins the main groundwater body. it is also groundwater fl ows and takes place in a homogeneous, isotropic, unconfi ned aquifer with hydraulic properties that remain constant with both time and space. an analytical and numerical solution of the transient groundwater fl ow is used in this study in order to predict the time-dependent of groundwater response in case of the planned artifi cial infi ltration from gaza waste water treatment plant. 2. material and methods 2.1. area of study gaza strip is located to the south-eastern coast of the mediterranean sea, between longitudes 34° 2” and 34° 25” east, and latitudes 31° 16” and 31° 45” north. it is an area of about 365 km2 and it is 45 km long and its width ranges of 6–12 km approximately (fig. 1). it is located in the transitional zone between a temperate mediterranean climate in the west and north, and an arid desert climate of the sinai peninsula on the east and south. the population characteristics are strongly infl uenced by political developments, which have played a signifi cant role in their growth and distribution along the gaza strip. the total population is around 1.300.000 (pcbs, 2002). temperature gradually changes throughout the year; it reaches its maximum in august (summer) and its minimum in january (winter). the average of the monthly maximum temperature ranges between 17.6 c° for january to 29.4 c° adnan m. aish: simulation of groundwater mound resulting from proposed artifi cial recharge of treated sewage effl uent case study... geologia croatica 69 allowed water to pass through. analysis of soil samples show ed that the hydraulic conductivity of unsaturated zone had an average of 18 m/d. the groundwater level was found at approximately 0.5 m above sea level, which means that the thickness of the saturated aquifer varied from approximately 30 m to 40 m as shown in the geological cross-section a–a–. the location of the geological cross-section is shown in (fig. 2). the pumping test using aquifer test model by means of a theis-curve fi t indicates that the phreatic aquifer has an average hydraulic conductivity of 24 m/d, and a specifi c yield of 0.24. the recharge area is around 90,000 m2 and the expected average treatment plant discharge rate is 60,000 m3/d. this would yield an infi ltration rate of 0.67 m/d on average. 2.2. groundwater mounding analysis to develop predictions of the mound geometry that may result below an infi ltration system, both analytical and numerical methods were employed. evaluations of these methods were conducted by using data gathered in the fi eld including water-level measurements, and hydrogeological data collected from palestinian water authority. 3. analytical modeling 3.1. methods the analytical solution provided by hantush (1967) to predict mounding beneath a rectangular infi ltration basin was applied by using a public-domain software program called moundht (finnemore, 1995). the method assum es that a constant vertical recharge is applied to a rectangular infi ltration area of fi xed dimension, and that the water table mound remains below the base of the infi ltration area at all times. the dimensions of the mound are governed by the basin size and shape, recharge rate and aquifer characteristics. most solutions are based on the usual assumptions of homogeneous and isotropic aquifers and vertical recharge at a uniform rate. the shape of a mound beneath a rectangular recharge area, expressed by zm, is the mound height in function of time and space (fig. 3), depending upon the artifi cial recharge fl ux, the specifi c yield and hydraulic conductivity of the aquifer. ments. the gaza strip pleistocene granular aquifer is an extension of the mediterranean seashore coastal aquifer. it extends from askalan (ashqelon) in the north to rafah in the south, and from the seashore to 10 km inland. the aquifer is composed of different layers of dune sandstone, silt clays and loams appearing as lenses, which begin at the coast and feather out to about 5 km from the sea, separating the aquifer into major upper and deep sub aquifers. the aquifer is built upon the marine marly clay saqiye group (goldenberg, 1992). in the east-south part of the gaza strip, the coastal aquifer is relatively thin and there are no discernible sub aquifers (melloul & collin, 1994). the gaza aquifer is a major component of the water resources in the area. it is naturally recharged by precipitation and additional recharge occurs by irrigation return fl ow. the consumption has increased substantially over the past years; the total groundwater use in year 2000 is about 145 mm3/year, the agricultural use about 90 mm3/year, domestic and industrial consumption about 51 mm3/year (metcalf & eddy, 2000). the groundwater level ranges between 5 m below mean sea level (msl) to about 6 m above mean sea level. area of study was the central wastewater treatment plant of the gaza strip, which was located to the south-east of gaza city. in the year 2007, the plant received about 60.000 cubic meters per day. the plant was close to less urbanized and agricultural areas. the specifi c location within the plant was the infi ltration basin with dimensions 200m x 450 m. figure 1 shows the location of the gaza strip and a schematic illustration of the wastewater treatment plant and recharge area as well as the 12 drilled boreholes. the hydrogeological investigation and laboratory analysis was carried out in the area of study by palestinian water authority where the recharge basin was located to obtain subsurface hydrogeologic properties of the aquifer and unsaturated zone to determine the suitability of the location for artifi cial recharge. the descriptions and interpretations of the site-specifi c hydrogeology are based on geological information collected at these locations. the site was covered with a sand layer with a thickness between 3 and 12 meters. in the unsaturated zone, clay lenses were present but there were no information available regarding the extension outside the site. the layers were semi permeable which means that they fi gu re 2: geological cross-section a–a– in the area of study (fig. 1). fi gu re 3: diagrammatic representation of the groundwater mounding (finnemore, 1995). geologia croatica 63/1geologia croatica 70 from equation of hantush (1967), the maximum height zm of the water table at the center of the mound, during water table rise caused by percolation to the water table from a rectangular recharge area, is given by h h = s*( , )m 2 0 2 y 2ith s a b– (1) where h0 is the initial height of the water table before percolation began, i is the constant rate of percolation, t is the time since percolation began, h– = 0.5 (h0 + hm), sy is the specifi c yield of the aquifer, s*(α, β) is the hantushs mound function given by a= l 4 s kht y 1 2( ) (2) b = w l a (3) where l is the recharge area length, w is its width, k is the hydraulic conductivity of the aquifer. because , where zm is the maximum mound height at time t, equation (1) can be rewritten as zm = it sy s* a,b( ) (4) the convenience and accuracy of equation evaluation provided by the computer, when added to the high prediction accuracy and wide range of applicability of hantushs method, make this a very attractive means of predicting groundwater mound heights. a computer program named moundht was applied to calculate groundwater mound in the area of study. 3.2. input parameters using the data obtained from the hydrogeological study, a recharge value is 0.67 m/d, and a rectangular recharge basin is 200 m x 450 m, hydraulic conductivity is 24 m/d, initial depth of saturated zone is 45 m and specifi c yield is 0.24. the obtained results are as shown in (fig. 4). at the center of the basin after 1400 days, the height of groundwater mound rises to about 18 m above the present groundwater table. therefore, an analytical solution such as the hantush method is considered an approximation of the fi eld response of the water table. 4. numerical modeling 4.1. methods to further evaluate the proposed infi ltration system, groundwater fl ow simulations were made by using the three-dimensional numerical model modflow (harbaugh & mcdonald, 1996). a commercial preand postprocessor software program, visual modflow, was used to conduct the modeling. modflow numerically evaluates the partial differential equations for groundwater fl ow (mcdonald & harbaugh, 1988). k h x k h y k h z w s h th h v s ¶ ¶ + ¶ ¶ + ¶ ¶ = ¶ ¶ 2 2 2 2 2 2 (5) where kh is the horizontal hydraulic conductivity, kv is the vertical hydraulic conductivity, h is the hydraulic head, ss is the specifi c storativity, w is the source/sink term, t is the time and x, y, z are the space coordinates. the interface of visual modflow is divided into three modules: the input module, the run module, and the output module. the input module provides users with the ability to create a graphical three-dimensional representation of the area of study. the modeler can assign values directly to the area of study and the software creates the appropriate fi les. the run module allows the user to alter the parameters and options that are run specifi c, such as the solver package, recharge and rewetting applications and the tolerances for convergence. the output module provides the user with the ability to display all of the modeling and calibration results. although visual modflow graphically represents the area of study, the inputs, and the outputs fi les are translated and processed by the version of modflow 2000 (harbaugh et al., 2000). 4.2. conceptual model and grid design the aquifer is considered as unconfi ned aquifer with a stratigraphy of 7 layers with alternating fi ner and coarser unconsolidated sediments belonging to the sandstone (kurkar) formation. the layers are approximately horizontal, with a small inclination towards the sea as shown in figure 2. the aquifer extends to areas far outside the chosen model domain. the model domain encloses an area of 6.6 x 5.8 km centered on the infi ltration area. the grid is chosen to be regular with a cell size of 50 m, with 132 columns and 116 rows. the model boundaries can be described in east of the gaza strip as a general head boundary; whereas in the west of gaza strip, it is a zero constant head boundary and both north and fi gu re 4: height of the groundwater mound under the center of the basin. adnan m. aish: simulation of groundwater mound resulting from proposed artifi cial recharge of treated sewage effl uent case study... geologia croatica 71 south are no fl ow boundary according to the water level contour map. the recharge was calculated with the wetspassmodel (aish et al., 2008). wetspass has a fl exible structure and is fully integrated within the gis arcview, based upon land use, soil type, some meteorological parameters, slope, groundwater depth, wind speed and potential evapotranspiration. wetspass calculates the spatially distributed groundwater recharge for the model. the spatially distributed recharge output of wetspass model can improve the prediction of simulated groundwater level and the locations of discharge and recharge areas for a steady state groundwater models. the groundwater abstraction was calculated from agricultural and municipal wells, according to palestinian water authority measurements. 4.3. input parameters hydraulic property values are assigned based on the hydrogeological investigation and previous studies. the hydraulic conductivity is assumed to be constant for each layer. the horizontal hydraulic conductivity of the sandstone aquifer is 24 m/d, specifi c storage is 2.2 x 10–6 (m–1) specifi c yield is 0.24 and total porosity is 0.30. the horizontal hydraulic conductivity of the clay layer is 0.2 m/d, specifi c storage is 3.1 x 10–6 (m–1), specifi c yield is 0.10 and total porosity is 0.45. the vertical conductivity was set to 10% of the horizontal hydraulic conductivity. the measured ground water level used for initial condition 4.4. model calibration calibration of the model was performed using available of 11 piezometers data. during the calibration the differences between measured and calculated piezometric heads were minimized by trial and error adjustment of the hydraulic conductivities. figure 5 shows the comparison between the calculated groundwater levels and average measured values. as it appears in (fig. 5), there is correlation coeffi ciency of 0.99 between measured phreatic level and simulated phreatic level. other indicators of the goodness of fi t are the root mean square error of 0.114 m and the mean absolute error of 0.099 m. hence, all tests indicate good correspondence between simulated and measured groundwater levels. 5. results and discussion three observation wells ob1, ob2 and ob3 in the center and at the edges of the recharge area were used for the study of the resulting groundwater mound. simulation shows that the groundwater mound beneath the center of an infi ltration area can be expected to rise around 18 m and to around 16 to 17 m at the edges after 1400 days as depicted in (fig. 6). the infi ltration will result in a rising groundwater table. the rise will be gradual and the full effect will be seen after 1400 days. figure 7a shows the groundwater level of initial heads (steady state conditions). simulated groundwater level with infi ltration after 100 days shows mound height of approximately 8 meters (fig. 7b). then, after 365 days, it show ed mound height of approximately 11 meters (fig. 7c). then, after 1400 days of groundwater level simulation, the maximum rise of the mound height of approximately 18 m (fig. 7d). the model simulations indicate that the water level will increase in the study area due to the infi ltration. fi gu re 5: comparison of measured and calculated groundwater levels. fi gu re 7a: simulated groundwater levels in steady state conditions. fi gu re 6: height of the groundwater mound beneath the recharge basin calculated with the numerical model. geologia croatica 63/1geologia croatica 72 fi gu re 7b: simulated groundwater levels with infi ltration after 100 days when the growth of the groundwater mound obtained with the model simulation was compared to the analytical solution (fig. 8), one could notice correspondence between numerical and analytical simulation. the small differences can be explained by the assumptions that were made in case of the analytical solution, i.e. a rectangular basin and an average groundwater table elevation to calculate the aquifer transmissivity. also, in the groundwater model, different ground layers are taken into account. at 1400 days both methods gave similar results, which indicate that the rise of the groundwater mound was about 18 m, which did not cause any problem to the site or surrounding areas. 6. conclusions both analytical and numerical modeling methods were used to predict the mound geometry that may develop in the unconfi ned aquifer beneath a proposed rapid infi ltration system. the hydrogeological fi eld and laboratory analyses were used to develop an analytical and a numerical model of the area of study. a steady-state, average-maximum treatment plant discharge rate of 60.000 m3/day was used for the analyses. the results of the numerical model simulations were compared with an analytical solution; both were found to be identical. thus, the groundwater mound would rise to about 8 m after 100 days and to about 11m after 365 days and about 18 m after 1400 days. as the unsaturated zone was about 30 to 40 m thick, the artifi cial infi ltration was considered to be feasible. references aish, a., batelaan, o. & de smedt, f. (2008): distributed recharge estimation for groundwater modeling using wetspass model, case study – gaza strip, palestine. submitting to the arabian journal for science and engineering (in press). asano, t. & wassermann, kl. (1980): groundwater recharges operations in california.– j. am. water works assoc., 72/7, 380–385. bianchi, w.c. & muckel, d.c. (1970): groundwater recharges hydrology, ars 41–161, usda, 62 p. choudhary, m. & chahar, b. (2007): recharge/seepage from an array of rectangular channels.– journal of hydrology, 343, 71–79. fi gu re 7c: simulated groundwater levels with infi ltration after 365 days fi gu re 7d: simulated groundwater levels with infi ltration after 1400 days. fi gu re 8: comparison of numerical and analytical results. adnan m. aish: simulation of groundwater mound resulting from proposed artifi cial recharge of treated sewage effl uent case study... geologia croatica 73 crook, j., asano, t. & nellor, mh. (1990): groundwater recharge with reclaimed water in california.– water environ. technol., 2/8, 42–49. finnemore, e.j. (1995): a program to calculate groundwater mound heights.– groundwater, 33/1, 139–143. glover, r.e. (1961): mathematical derivations as pertain to groundwater recharge. mimeographed report, agricultural research service, u. s. dept. agriculture, ft. collins, colo., 81 p. goldenberg, l.c. (1992): evaluation of the water balance in the gaza strip. geological survey, report tr-gsi/16/92 (in hebrew). gvirtzman, g., shachnai, e., bakler, n. & ilani, s. (1984): stratigraphy of the kurkar group (quaternary) of the coastal plain of israel. geological survey of israel, current research, 70–82. hantush, m.s. (1967): growth and decay of groundwater mounds in response to uniform percolation.– water resources research, 3, 227–234. harbaugh, a. & mcdonald, m. (1996): user’s documentation for modflow-96, an update to the us geological survey modular fi nite-difference groundwater fl ow model. us geological survey, open-fi le report, 96–485. harbaugh, a., banata, e., hill, m. & mcdonald, m. (2000): the u.s. geological survey modular groundwater model-user guide to modularization concepts and the groundwater fl ow process. jury, w. & gardner, w. (1991): soil physics. fifth edition. isbn: 0-471-83108-5, 4–18. latinopoulos, p. (1986): analytical solutions for strip basin recharge to aquifers with cauchy boundary conditions.– journal of hydrology, 83, 197–206. lee, l.j.e., lawrence, d.s.l. & price, m. (2006): analysis of water-level response to rainfall and implications for recharge pathways in the chalk aquifer, se england.– journal of hydrology, 330, 604–620. marino, m. a. (1967): hele-shaw model study of the growth and decay of groundwater ridges.– journal of geophysics research, 72, 1195–1205. marino, m.a. (1974): water table fl uctuations in response to recharge.– american society of civil engineers, journal of irrigation and drainage division, 100, 117–125. marmion, k.r. (1962): hydraulics of artifi cial recharge in non homogeneous formations.– water resources center contribution, 48, univ. of california, berkeley, calif., 88 p. mcdonald, m.g. & harbaugh, a.w. (1988): a modular threedimensional fi nite difference groundwater fl ow model.– usgs techniques of water resources investigation report, book 6, ch a1, 586 p. melloul, a.j. & collin, m. (1994): the hydrological malaise of the gaza strip.– isr. j. earth sci., 43/2, 105–116. metcalf & eddy (2000): the gaza coastal aquifer management plan – task 3 appendix a, usaid, contract no. 294-c-99-0003800, 64 p. palestinian central bureau of statistics (pcbs) (2002): projected population in the palestinian territory, establishments report, ramallah, palestine, 5 p. rao, n. h. & sarma, p. b. s. (1983): recharge to fi nite aquifer from strip basins.– journal of hydrology, 66, 245–252. todd, d.k. (1980): groundwater hydrology, 2nd ed. new york, usa, john wiley & sons, 535 p. welton, w.c. (1970): groundwater resources evaluation. mc grawhill book co., inc., new york, 664 p. manuscript received march 12, 2009 revised manuscript accepted december 08, 2009 available online february 28, 2010 in memoriam boskovic.indd yet another dear colleague and friend, mr. dean braco bošković, a great man, has passed away. for years he was one of the leading people in the institute of geology zagreb, a man whose work has, over time, left a significant impact on the status of our profession in croatian society. allow us to briefly recollect the most important moments in his life. he was born on april 11, 1929 to an old, traditional family of railwaymen in selska street, in trešnjevka, an old part of zagreb where the working class used to live. he also completed his secondary school education in zagreb. from 1948 to 1950 he was a professional sportsman in many sport and gymnastic associations, but was equally dedicated to music, and as an amateur musician organised numerous musical events and festivals in zagreb. he enrolled at the school of mining and geology of zagreb university, and graduated with an honours degree in 1957. as a student he worked as an undergraduate assistant in the department of the mineralogy and geology institute and was fully committed to all activities conducted by the institute – actively participating in field and laboratory work, in writing professional and scientific papers on geology, petrology, and mineral deposits. after completing his studies he was appointed to the position of chief engineer for mining operations in the sisak steel works, and in 1958 became manager of the iron mine in bešlinac and bukovica, and of the coal mine at tremušnjak. in 1960 he was appointed to the position of general manager of the iron mine ljubija where he worked until 1966 on reconstruction and investments operations. then, he was relocated to zagreb, to the position of assistant director of the institute of geology and remained in office until 1975, when he became director of the institute himself. his next important position was director of the geological survey of croatia within the body which functioned at that time under the committee for science, technology and informatics. at the same time, while performing everyday routine jobs, he also published 37 studies in the field of planning, financing and organising geological research works. along with his professional obligations, he was active in the croatian chamber of commerce, in the funds for development of science of the time, in various associations of croatian geologists and mining engineers, where he continuously emphasised the paramount importance of geological research for the development of the croatian economy. among other things, he was one of the authors of the draft law on geological research. he paid exceptional attention to working conditions in the institute, to modernisation of laboratories and research equipment, and achieved significant improvement of all operations conducted by the institute of geology when, thanks to his endeavours, the new institute headquarters was built on its present location in sachsova street, zagreb. dean bošković was a member of the croatian geological society, society of engineers and technicians of croatia, and scientific oil council of the croatian academy of sciences and arts. he retired on april 1, 1993. his retirement did not dampen his enthusiasm and optimism, the two most dominant features of his character; he continued working in the geological geologia croatica 57/2 221–222 zagreb 2004 in memoriam dean bošković, b.sc. 1929–2003 222 geologia croatica 57/2 survey as an adviser and associate; always full of ideas to benefit the profession, he remained a committed member of the geological community, a dear friend and colleague whose frequent visits to the institute were always welcomed with joy and friendliness. despite his numerous obligations he was always ready to provide help and assistance to his junior colleagues. even in moments of personal tragedy he was able to overcome pessimism and sorrow and show great strength of character. devoted to his family, his children, and most of all to his grandchildren, his warmth and kindness appealed to all those who came in contact with him, in particular his younger colleagues to whom he often appeared as father and friend. on behalf of all employees of the institute of geology, we would like to pay tribute to mr. bošković for all the achievements of his fruitful and generous career, and for everything he left as a legacy to be shared by his colleagues, friends and co-workers. may he rest in peace! dubravko matičec and ivo velić aljinovic.indd 313 � ab stra ct flysch deposits that crop out in the elongated coastal area of the vinodol valley (external dinarides), and particularly in the slani potok (‘salty creek’) catchment, are characterized by excessive erosion. formation of badlands, creeping and sliding processes have been related to crystallization of thenardite. unusually intense erosion is caused by the dispersive effect of sodium on clay particles (derived from pelitic fl ysch intervals) in solution, as well as by expansion of thenardite during transformation into a deckahydrate (with a four fold increase in volume). the search for a sodium source required for thenardite crystallization has focused on a particular composition of slani potok eocene fl ysch rock types. slani potok fl ysch is predominantly composed of pelitic intervals, with subordinate sandstones and biocalcirudites. sandstones and biocalcirudites contain appreciable amounts of siliciclastic detritus. lithic fragments are represented by volcanic rocks revealing porphyry structures possibly andesite or altered volcanic glass fragments, quartzite, schists, shales, and carbonate grains. high amounts of sodium and barium (0.93–1.09 % and 267–276 mg/kg respectively), in marls and sandstones, is essentially ascribed to a particular composition of fl ysch, refl ecting its area of provenance. a palaeozoic clastic complex with barite mineralization, (black shales, sandstones and conglomerates), as well as a mesozoic hornblende andesite located near fužinski benkovac in the gorski kotar region, are interpreted as fl ysch source rocks. sodium at least could be partly leached from the lithic and feldspar grains in clastic rocks, due to circulation of pore fl uids. an increased amount of sulphur, barium and strontium in fl ysch can be related to that of a barite ore complex in the source area of the gorski kotar region. transportation and deposition of material eroded from the hinterland (north of slani potok), suggests turbidity current fl ow was transverse to the main axis of the eocene foreland basin striking nw-se. keywords: composition of fl ysch deposits, origin of fl ysch deposits, excessive erosion, slani potok, eocene, external dinarides, croatia the origin and composition of fl ysch deposits as an attribute to the excessive erosion of the slani potok valley („salty creek“), croatia � dunja aljinović, †vladimir jurak, marta mileusnić, dragutin slovenec and filip presečki faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, 10 000 zagreb, croatia; (dunja.aljinovic@rgn.hr) doi: 104154/gc.2010.25 geologia croatica 63/3 313–322 11 figs. 1 tab. zagreb 2010 geologia croaticageologia croatica 1. introduction flysch domains in croatia occur along the elongated area of the external dinarides (see overview in marinčić, (1981)). although all eocene fl ysch domains in the external dinarides are exposed to a high degree of erosion (jurak et al., 2002, 2003, 2005), erosion is unusually intense in the slani potok catchment. this catchment (with an area of 3 km2) is part of the vinodol valley (fig. 1) where erosion is associated with intensive creeping and sliding processes. accumulation of a colluvial soil-like mass, disposed to fl owing, geologia croatica 63/3geologia croatica 314 forms badlands type terrain (figs. 2 & 3). such erosion represents a unique phenomenon within the dinaridic fl ysch domain and has been investigated by jurak et al. (1996, 2005, 2006), mileusnić et al. (2004), benac et al. (2005). previous investigations determined the occurrence of the mineral thenardite, (sodium sulfate – na2so4) in the slani potok catchment. this mineral crystallizes by effl orescence at the surface of sedimentary rocks during the dry season (summer – july, august) – fig. 4 and dissolves during wet seasons. dissolved thenardite results in the salty taste of the slani potok creek and is the origin of its name. according to mileusnić et al. (2004) and jurak et al. (2005, 2006) excessive erosion of the slani potok fl ysch complex occurs due to a lithological composition characterized by the prevalence of clay particles in pelitic fl ysch intervals, the presence of swelling minerals, sodium rich pore water, and occurrence of the sodium mineral thenardite. the aim of this study is to determine the source of sodium and sulphur needed for thenardite crystallization. 2. geological setting the slani potok catchment is part of the larger mala dubračina catchment in the elongated and irregularly shaped vinodol valley which has a nw-se axis. in the vinodol valley, the oldest rocks are cretaceous platform carbonates. tectonic movements at the end of cretaceous formed the thrust fold belt of the external dinarides (marinčić, 1981; bergant, 2003). in front of the uplifted thrusts, in a deep foreland basin, early-middle eocene foraminiferal limestone and middle eocene fl ysch were deposited (šušnjar et al., 1970; grimani et al., 1973). late eocene limestone, fossiliferous conglomerates and sandstones, (equivalents of late eocene/oligocene promina figure 1: location of investigated area with air photograph of vinodol valley and slani potok catchment area (light gray). figure 3: creeping and sliding processes in slani potok valley. arrows are pointing margins of slided rock mass. figure 2: coluvial mass forming badland. aljinović et al.: the origin and composition of fl ysch deposits as an attribute to the excessive erosion of the slani potok valley ... geologia croatica 315 formation), breccias (equivalent to the late eocene/oligocene jelar formation), coal-bearing late pliocene brackish clastics, and quaternary talus breccias have also been determined in the vinodol valley (šušnjar et al. 1970; grimani et al., 1973 and blašković & tišljar, 1983). blašković (1999), describes the vinodol valley as a syncline in which the axis is parallel to the valley strike. the syncline is mostly composed of middle eocene fl ysch deposits. marginal rocks of the vinodol valley are represented by upper cretaceous limestones and early-middle eocene foraminiferal limestone (šušnjar et al., 1970) (fig. 5). the late eocene limestone breccia and quaternary deposits have a patchy occurrence in the valley. quaternary talus breccias occurred as a consequence of tectonic activity and were deposited on a foothill of steep cliffs (faults). the fault systems, that controlled the evolution of the vinodol valley morphology, have variable kinematic features that change along their strike and dip, merge into reverse or even over-thrust structures (blašković, 1997). the middle eocene fl ysch deposits constitute the central area of the slani potok catchment. flysch is mostly represented by thick pelitic intervals interlayered with minor sandstones and biocalcirudites (‘nummulite breccias’). as a result of intensive processes of sliding, creep and formation of a colluvial soil mass (badlands), the fl ysch deposits are not currently in their original position, but instead exhibit a rather chaotic appearance with overturned, fragmented and deformed beds (fig. 6). the mineral thenardite occurs on the surface of all rock types in the slani potok area (mileusnić et al., 2004; jurak et al., 2005) – (fig. 4). it has been documented as the fi rst occurrence of this mineral in croatia (mileusnić et al., 2004). as there is no occurrence of salts in any of the fl ysch terrains, the appearance of thenardite seems to be a unique phenomenon of the slani potok fl ysch in the whole figure 4: thenardite crystals (white) precipitated at the surfaces of fl ysch sedimentary rocks. fi gu re 5: schematized geologic map of the vinodol valley with slani potok catchment area. of the external dinarides. therefore we investigated a possible source of sodium and sulphur required for the crystalgeologia croatica 63/3geologia croatica 316 lization of thenardite. the petrographic and geochemical composition of all fl ysch rock types in slani potok has been studied in order to defi ne the provenance of the detrital material. therefore the geological framework of the hinterland has been taken into consideration as a potential source area. the hinterland, located north of the slani potok area, consists of a palaeozoic clastic complex (black shales, sandstones and quartz rich conglomerates), with barite and pyrite ore mineralization (jurković, 1959; šiftar, 1981; alji nović et al., 2000), and a mesozoic carbonate complex, with hornblende andesite (in the vicinity of fužinski benkovac (vragović & golub, 1969)). the hornblende andesite was attributed to intense low temperature (hydrothermal) alteration manifested as propylitized and albitized rock minerals with andesine, containing 33 vol. % of anorthite as well as pure albite as a common constituent (vragović & golub, 1969). 3. methods the lithological, mineralogical and geochemical characteristics of the flysch sedimentary rocks have been analyzed in order to determine the origin of sodium and sulphur ions necessary for the crystallization of thenardite. several samples of sandstones and biocalcirudite have been studied micropetrographically and chemically. some samples were taken randomly (due to the restricted occurrence of fl ysch in the original position) while some are from the 8 m thick section that has been measured and sampled (fig. 7). samples of pelitic fl ysch intervals from the section were analyzed for carbonate content, mineral and chemical composition. in order to compare the surface and internal chemical composition, two marl samples were taken from the same bed, one from the surface (sample number spp 5a), and another from 0.5 m depth (spp 5b). the mineral and chemical composition of calcitic platelets, accumulated at the surface of fl ysch rocks, has also been analyzed. petrographic investigation suggested further micropetrographic analyses of the samples and determination of the main constituents in sandstones using semi quantitative visual estimation (terry & chilingar, 1955). the chemical composition (main macroand microelements) has been determined in four rock samples (from 2 sandstones and 2 marls) as well as one sample of a calcitic platelet. prior to analysis, samples were ground in an agate mortar followed by fusion with libo4/li2b4o7. their chemical composition was determined by inductively coupled plasma emission spectroscopy (icp-es) in the acme analytical laboratory, canada. the carbonate content was determined according to scheibler’s method (iso 10693). 4. results 4.1. petrological and mineralogical characteristics of fl ysch deposits flysch outcrops in the slani potok catchment area are represented by the prevalence of pelitic fl ysch intervals determined mainly as marls and silty marls, calcareous clayey siltstones, siltstones, and clayey siltstones (mileusnić et al., 2004; jurak et al., 2005). subordinate fl ysch sequences include sandstones. very restricted occurrences of biocalcirudite have also been observed within fl ysch deposits. a graphic log of a short fl ysch succession in its primary position is shown in figure 7. sandstones and marls of this section are arranged in fi ning upward sequences containing fi ne-grained sandstones at the base and marls at the top. fi ne -grained basal sandstones exhibit small scale cross-lamination which can be attributed to the tc intervals of turbidite sequences. sandstones of tc intervals are overlain by parallel laminated very fi ne-grained sandstones (td interval), that gradually pass upwards into silty marl or marl of te intervals. six tc-te and two td–te sequences have been logged and are shown in figure 7. their recurrence in the vertical succession can be interpreted as deposition from several distal turbidity currents. sandstones have been determined as fi ne-grained lithic grey wackes (tc and td intervals) with dominantly siliciclastic detritus (fig. 8). quartz grains are present with ca. 50 vol. %, followed by lithic fragments (ca. 30 vol. %), and feldspar grains (plagioclase, orthoclase and microcline) for ca. 20 vol. %. quartz grains are mainly represented by mono crystalline undulose grains. polycrystalline quartz grains are the dominant component among the lithic fragments. subordinate grains with faintly preserved porphyry textures with plagioclase phenocrysts surrounded by microcrystalline figure 6: chaotic appearance of fl ysch strata. aljinović et al.: the origin and composition of fl ysch deposits as an attribute to the excessive erosion of the slani potok valley ... geologia croatica 317 figure 7: investigated section. figure 8: composition of sandstone. note prevalence of siliciclastic material (lithic particles and feldspars are marked by arrow). stained with alizarin and k-ferricyanide. microphotograph; crossed nicols. figure 9: devitrifi ed volcanic particles in the sandstone showing faint porphyric structure (arows) and altered feldspars. stained with alizarin and k-ferricyanide. microphotograph; plane polarised light. quartz or volcanic glass occur (fig. 9). they are usually intensively altered and exhibit a brown clayey patina. other lithic grain types correspond to quartzite, schists, shales, limestones and dolostones. fossils are rarely present in all the examined samples. a clayey carbonate matrix fi lls the intergranular pore spaces. the primary matrix is partially recrystallized to chlorite. sandstone grains with porphyry or faint altered porphyry textures suggest a volcanic origin for these grains. furthermore, grains showing a microcrystalline quartz matrix may geologia croatica 63/3geologia croatica 318 be interpreted as altered volcanic glass particles. the presence of volcanic, metamorphic and sedimentary rocks suggests a complex provenance for the sediments. acidic or intermediate magmatic rocks are assumed as the main source of lithic particles. the main constituent of the rather restricted biocalcirudite is fossil detritus, among which nummulites fragments are most common. in addition, fragments of echinoids and lithothamnium algae occur similarly as magdalenić (1972) reported for similar rock types from the istrian peninsula. nevertheless, with the exception of fossil detritus in the biocalcirudite from slani potok, they contain an appreciable amount of coarse grained siliciclastic detrital material. it is worth mentioning that within the siliciclastic detritus, lithic fragments are the most common constituent, followed by quartz and feldspar grains. lithic fragments clearly show a porphyry texture, whereas plagioclase phenocrysts are surrounded by altered microcrystalline quartz and a chlorite matrix (fig. 10). volcanic particles have been altered in a similar manner to the lithic grains described in sandstones. metamorphic grains have also been discerned. pelitic fl ysch intervals in the slani potok area have been characterized mainly as marls, silty marls, calcareous clayey siltstones, siltstones, and clayey siltstones (mileusnić et al., 2004; jurak et al., 2005). the amount of clay in all the analyzed pelitic lithotypes varies from 2.5–36.9 wt. % where particles less than 2 μm prevail. silty grains comprise 28.7–87.8 wt. %. the carbonate component varies from 3.8–60.0 wt. %. a small amount of sand grains (< 10 wt. %) is usually present in the pelitic rocks. semiquantitative xrd analyses of the mineral composition showed that the main constituents of pelitic rocks are: muscovite and illitic material (<30 wt. %), quartz (<25 wt. %), calcite (<15 wt. %) and feldspar (<10 wt. %). minor constituents include chlorite, kaolinite, smectite and pyrite (jurak et al., 2005). thenardite, documented earlier by mileusnić et al. (2004) and jurak et al. (2005), seems to be the most characteristic feature of the slani potok fl ysch deposits. the biggest crystals observed by sem have diameters of up to 2 μm (mileusnić et al., 2004). crystallization of thenardite (fig. 4) has been interpreted as being due to effl orescence processes in the dry summer season. during the wet season, thenardite dissolves and therefore surface water is enriched in sodium and sulphate ions (mileusnić et al., 2004; jurak et al., 2005). the surface of pelitic fl ysch intervals in slani potok has often been covered by calcitic platelets as loose detritus (fig. 11). it is assumed that calcitic platelets were formerly a thin crust at the surface of sediments or soils. the calcite crust breaks due to creeping or sliding processes and forms angular calcitic platelets. the occurrence of calcitic platelets is a diagenetic feature. xrd analyses indicate calcite as the only constituent of such platelets which are composed of elongated prismatic crystals. calcite veins of similar appearance have not been found within the marls and sandstones. 4.2. geochemical characteristics of fl ysch deposits results of macroand microelement analysis of sandstones, marls and calcitic platelet samples are listed in table 1. all analyzed rock types have a high content of sodium and barium. sandstones contain higher amounts of silicon and lower amounts of aluminium compared to marls. amounts of magnesium and potassium are higher in marls, while the content of sodium is similar in both rock types. calcium is higher in the sandstones, while trace elements are enriched in the marls. it can be clearly seen that the composition of macroand microelements of the marl sampled at the surface (spp 5a) figure 10: microphotograph of biocalcrudite (‘nummulite breccia’). note abundance of siliciclastic particles and a large lithic fragment on the right, clearly showing prophyric structure, with plagioclase fenocrysts and altered microcrystalline quartz/chlorite matrix. stained with alizarin and k-ferricyanide. plane polarized light. figure 11: calcite platelets covering a surface of pelitic fl ysch rocks. aljinović et al.: the origin and composition of fl ysch deposits as an attribute to the excessive erosion of the slani potok valley ... geologia croatica 319 and the marl sampled at a depth of 0.5 m (spp 5b), is very similar (table 1). the surface marl sample has slightly depleted mn and sr compared to the marl sample at depth. chemical analysis of calcite platelets showed appreciable contents of barium and strontium (table 1). xrd analyses of calcitic platelets did not show any barium or strontium minerals, but high contents of ba and sr can be in ter preted as isomorphic substitution of calcium ions by ba and sr in calcite. 5. discussion marls and pelitic rocks predominate in fl ysch deposits of the slani potok area. they represent the pelitic intervals of turbidite sequences. sandstones and biocalcirudite (‘nummulite breccia’) occur as a much thinner tc and td turbiditic intervals. these rock units forming the slani potok catchment area have been subjected to specifi c types of erosion that are characteristic of excessive erosion. (jurak et al., 2002, 2005; mileusnić et al., 2004). according to jurak et al. (2005), and mileusnić et al. (2004), excessive erosion can be related to the occurrence of thenardite (sodium sulphate). thenardite crystallizes by effl orescence on the surface of sedimentary rocks and soils during the dry and warm summer period and dissolves during the wet seasons. the interrelationship of thenardite and the erosion of fl ysch rocks is two fold: 1) thenardite transforms into mirabilite (sodium sulphate decahydrate) on contact with water, increasing its volume at least four-fold. this transformation can intensify erosion forming pressure in the host rock and 2) available sodium in solution acts as a dispersive agent to the clay particles of the pelitic fl ysch intervals. both effects may be drivers for the creeping and sliding processes as well as the formation of a colluvial clay rich substratum subjected to mass fl ow. the signifi cant excessive erosion that has been interpreted as the infl uence of thenardite in the slani potok area resulted in a search for the source of sodium and sulphur needed for thenardite crystallization. the composition of fl ysch rocks was examined in an attempt to defi ne the provenance of the fl ysch and a possible source of sodium and sulphur. flysch rocks were deposited by turbidity currents in the middle eocene in a deep water environment. tectonic movements at the end of the cretaceous form a complex foreland basin on the south-western side of the fault thrusts of the external dinarides (marinčić, 1981; bergant, 2003). it is accepted that activation of the numerous dinaridic (nwse) faults triggered immense gravitational fl ows and that fl ysch was deposited by turbidity currents. models for palaeo-transport of the turbidity currents have been discussed by numerous authors including magdalenić (1972), marinčić (1981), tunis & venturini (1992), and babić et al. (2007). as the fl ysch domain represents an elongated trough with nw-se stri ke, magdalenić (1972), proposed a longitudinal tran sport direction toward the ese, which derived material from the alps, and a transverse component toward the sw where the source area was the rising dinarides in palaeogene times. a similar pattern was proposed by marinčić (1981), but assumed the main transport paths were transverse toward the sw (from the bosnian ridge), and defl ection of the currents to the ese in the deeper part of the basin. according to tunis & venturini (1992) the main transport direction was transverse to the nw-se strike of the uplifted fault thrust belt, while babić et al. (2007) explicitly reported transverse transport but with the direction toward the ne. considering the particular composition of the fl ysch deposits in slani potok (prevalence of siliciclastic particles versus carbonate grains and presence of thenardite), it was necessary to determine a potential provenance area and possible source of sodium and sulphur. the difference in fl ysch composition stems from the composition of adjacent terrains and distances from the source area. flysch sequences derived dominantly from carbonate platforms contained mainly carbonate detritus (magdalenić, 1972; tunis & venturini, 1992; babić et al., 2007) which is not the case for the slani potok fl ysch units. the hinterland (at the north of the slani potok area) consists of palaeozoic shales, sandstones, and quartz rich conglomerates, with barite and pyrite ore mineralization (jurtable 1: chemical analyses of fl ysch samples. sample spp 3 sp 0 spp 5a spp 5b type of material sandstone sandstone marl marl calcitic plate si (%) 32.58 31.87 26.12 24.43 0.67 al (%) 4.10 3.39 8.61 8.59 0.21 fe (%) 2.13 1.70 4.88 4.94 0.95 mg (%) 0.68 0.80 1.60 1.60 0.37 ca (%) 4.8 6.25 2.45 3.42 36.04 na (%) 1.09 0.93 0.99 0.98 0.02 k (%) 1.07 0.93 2.37 2.33 0.06 ti (%) 0.29 0.23 0.49 0.47 0.01 p (%) 0.038 0.031 0.057 0.053 0.002 mn (%) 0.06 0.08 0.06 0.1 0.38 cr (%) 0.021 0.023 0.018 0.016 <0.001 ba (ppm) 181 169 267 273 7793 ni (ppm) 62 36 120 104 <20 sr (ppm) 123.6 119.4 149.3 170.5 590.9 zr (ppm) 138 114 166 152 6 y (ppm) 16 16 28 29 6 nb (ppm) 14 16 22 18 10 sc (ppm) 7 6 18 18 <1 loi (ppm) 7.3 9.2 9.1 11.1 42.5 c/tot (ppm) 1.58 2.18 1.17 1.42 11.99 s/tot (ppm) 0.15 0.12 0.33 0.16 0.18 geologia croatica 63/3geologia croatica 320 ković, 1959, šiftar, 1981; aljinović et al., 2000), and a mesozoic carbonate complex, with hornblende andesite in the vicinity of fužinski benkovac. it was assumed that the gorski kotar might be the source area of the slani potok fl ysch rock units. prior to deposition of the fl ysch by turbidity currents, dinaridic land masses were subjected to intensive erosion. a high amount of pelitic detritus, forming thick td–e fl ysch intervals, was possibly derived from the erosion of palaeozoic shales. the detrital siliciclastic component of the fl ysch sandstones and biocalcirudites may also have originated from palaeozoic sandstones or conglomerates located in the gorski kotar area. analysed sandstones and biocalcirudites from the slani potok catchment contain a signifi cant amount of lithic fragments of volcanic origin, probably andesite, as well as altered volcanic glass particles. the hornblende andesite located in the gorski kotar (vicinity of fužinski benkovac) north of the studied area, is considered as a source rock. this volcanic rock was attributed to the intense low temperature (hydrothermal) alteration manifested as propilitized and albitized rock minerals (vragović & golub, 1969). these authors also determined pure albite as a common constituent of andesite. thus andesitic complexes from fužinski benkovac contain even more sodium content than usual. it is likely and possible that feldspar and volcanic particles derived from sodium rich andesite near fužinski benkovac could increase the sodium content in the sedimentary rocks of the slani potok area. intermediate plagioclase as well as diagentic albite and propylite from andesite can produce appreciable amounts of sodium during weathering. thus the increased sodium content in the analyzed samples can stem from the specifi c composition of the fl ysch deposits. the composition of macroand microelements has been compared to the soil geochemical map data for the fl ysch area in istria (peh et al., 2003). flysch samples from slani potok do not differ signifi cantly from the fl ysch deposits in istria, except for the sodium and barium contents. mean concentrations of sodium in istrian fl ysch are 0.55 wt. %, while in the slani potok fl ysch it is double this value. the mean concentration of barium in istrian fl ysch is 233 mg/kg, while in slani potok pelitic fl ysch intervals the mean concentration is higher (267–276 mg/kg). it is worth pointing out that stream water has an appreciable amount of dissolved sodium while water at the spring of slani potok creek has average sodium content, indicating a sodium source from fl ysch and not from the groundwater. sulphur is present in the pelitic fl ysch deposits in the form of pyrite (magdalenić, 1972). oxidation of pyrite by weathering processes at and near the surface can lead to the production of sulphate minerals. the uplifted palaeozoic ore complex from the gorski kotar region might have been infl uencing the composition of fl ysch deposits of the slani potok area. it is characterised by complex barite ore paragenesis where barite is the main ore mineral, accompanied by pyrite, quartz and celestine (jurković, 1959; šiftar, 1981; aljinović et al., 2000). šiftar (1981) indicated bacteriogenic dissolution of barite, and therefore also dissolution of barium, sulphur and strontium contained in barite. this evidence suggests that barium, sulphur and strontium could have been derived from the deteriorated ore complex in gorski kotar. complex recent diagenetic processes also infl uenced deposition in slani potok. a vast quantity of calcite crystallizes from solution saturated with carbonates as a thin crust at the surface of sediments or soils. the calcite crust breaks and forms angular calcitic platelets. high values of barium and strontium in calcitic platelets, not typical for the primary sedimentary rocks, is possibly related to deterioration of the ore complex in the hinterland (gorski kotar region) and has a diagenetic origin. if the gorski kotar region, located north of the slani potok valley, is considered the source area, it means that turbidity currents transported material from the uplifted hinterland (uplifted cordillera belt) and that palaeotransport was transverse to the strike of the foreland basin axis. our observations show that the most likely transport directions are from the n-ne to the s-sw. 6. conclusion flysch deposits that crop out in the slani potok catchment area, (as a part of vinodol valley), have been subjected to excessive erosion. a colluvial soil-like clayey mass attributed to creeping and sliding processes forms terrains of the badlands type. according to jurak et al. (2002, 2005) and mileusnić et al. (2004), the phenomenon of excessive erosion can be related to the occurrence of the mineral thenardite (na2so4). increased concentrations of sodium and sulphate ions in surface water lead to the crystallization of thenardite in the dry and warm season. water evaporating from the surface of sediment/soil in the dry season increases saturation of sodium and sulfate ions and thenardite occurs as effl orescence crusts on the surface of rocks/soils. when thenardite is later dissolved, sodium solutions act as a dispersive agent on the clay particles from fl ysch pelitic rocks types. as thenardite transforms into mirabilite (sodium sulphate decahydrate), there is a four fold increase in volume of the mineral. frequent crystallization and dissolution of thenardite becomes the main driver for the erosion and this process results in mass wasting and disintegration of rock masses. surface waters in slani potok are enriched in sodium and sulphate, while the ground water does not have any appreciable amount of these ions. geochemical analysis of marls and sandstones indicate a high amount of sodium and barium (0.93–1.09 % and 267–276 mg/kg, respectively). together this suggests that increased sodium and sulphate concentrations can be ascribed to the particular composition of fl ysch rock units. the composition of slani potok fl ysch rocks differs from other fl ysch areas in the external dinarides. the explanation for this was discovered in the complex composition of the provenance area – the gorski kotar region located in the hinterland of the slani potok. in general, in the external dinarides, fl ysch have been deposited in a deep foreland basin formed in front of the dialjinović et al.: the origin and composition of fl ysch deposits as an attribute to the excessive erosion of the slani potok valley ... geologia croatica 321 naridic thrust belt that has a longitudinal axis striking nw-se. turbidity currents transported flysch from the source area to the north of slani potok, in a direction transverse to the main axis of the foreland basin, (from the n-ne to the s-sw), depositing sediments in the study area. the particular composition of fl ysch deposits – prevalence of pelitic rocks, appreciable amounts of siliciclastic material in sandstones and biocalcirudites, with signifi cant amounts of volcanic particles and feldspar grains, stems from the geological framework of the source area. it was assumed that a palaeozoic clastic rock complex (black shales, sandstones and quartz rich conglomerates with barite ore mineralization), and mesozoic carbonates with hornblende andesite cropping out in the gorski kotar region, hinterland of slani potok, was the provenance from where the clastic detritus has been derived. thick pelitic fl ysch intervals are related possibly to derivation of vast quantities of fi ne grained material from black shales as well as sandy particles from gorski kotars’ palaeozoic and mesozoic sandstones, conglomerates, carbonates and andesite. some sodium could be lea ched from the lithic and feldspar grains due to circulation of pore fl uids while the increased amount of sulphur, barium and strontium in the fl ysch can be related to the barite ore complex in the source area of the gorski kotar region. acknowledgement this paper is dedicated to our dear colleague and professor dr. sc. vladimir jurak who passed away in february 2010. he worked in slani potok for years and introduced all of us to the interesting erosion phenomenon. the authors kindly thanks dr. sc. marta crnjaković for her thorough review, comments and suggestions that have signifi cantly improved this manuscript. we would also like to express our gratitude to dr. sc. bojan ogorelec and julie robson for their reviews. the results presented are part of the following scientifi c projects: 1951953068-2704; 195-0000000-3202; 195-0000000-2233, 195-00000003205 (ministry of science, education and sports, republic croatia). references aljinović, d., slovenec, d., durn, g., slavković, r., miko, s. & kolarić, d. (2000): mineralne pojave u paleozojskim klastitima i donjotrijaskim karbonatima gorskog kotara (hrvatska) [mineral occurrences in palaeozoic clastic and early triassic carbonate rocks in the gorski kotar, croatia – in croa tian].– in: vlahović, i. & biondić, r. (eds.): zbornik radova 2. hrvatskog geološkog kongresa, institut za geološka istraživanja, 59−65. babić, lj., hernitz kučenjak, m., ćorić, s. & zupanić, j. (2007): the middle eocene age of the supposed late olicecene sediments in the fl ysch of the pazin basin (istria, outer dinarides).− natura croatica, 16/2, 83−103. benac, č., jurak, v., oštrić, m., holjević, d. & petrović, g. (2005): pojava prekomjerne erozije u području slanog potoka (vinodolska dolina).− in: velić, i., vlahović, i. & biondić, r. (eds): abstract book, 3rd croatian geological congress, 173−174. bergant, s., tišljar, j. & šparica, m. (2003): eocene carbonates and flysch deposits of the pazin basin.− in: vlahović, i. & tišljar, j. (eds.): field trip guidebook: evolution of depositional environments from the palaeozoic to the quaternary in the karst dinarides and the pannonian basin, 22nd ias meeting of sedimentology, institut za geološka istraživanja, 57−64. blašković, i. (1997): the helicoidal fault systems of vinodol (croa tia) and their genesis.− geol. croat., 50/1, 49−56. blašković, i. (1999): tectonics of part of the vinodol valley within the model of the continental crust subduction.− geol. croat., 52/2, 153−189. blašković, i. & tišljar, j. (1983): prominske i jelar naslage u vinodolu (hrvatsko primorje) [promina and jelar deposits in the vinodol area – in croatian].− geol. vjesnik, 36, 37−50. grimani, i., šušnjar, m., bukovac, j., milan, a., nikler, l., crnolatac, i., šikić, d. & blašković, i. (1973): tumač osnovne geološke karte sfrj za list crikvenica 1:100000 [geology of the crikvenica sheet, basic geological map of sfry 1:100000 – in croatian].− savezni geološki zavod, beograd, 47 p. grimani, i., vulić, ž. & blašković, i. (1970): osnovna geološka karta sfrj 1:100 000, list crikvenica l 33-101 [basic geological map of sfry 1:100 000, crikvenica sheet – in croatian].− institut za geološka istraživanja zagreb, savezni geološki zavod, beograd. iso 10693 (1995): soil quality – determination of carbonate content – volumetric method. jurak, v., matković, i., miklin, ž. & mihalić, s. (1996): data analysis of the landslides in the republic of croatia: present state and perspectives.– proc. 7th int. symp. on landslides, balkema. landslides, 3, 1923–1928. jurak, v., petraš, j. & gajski, d. (2002): istraživanje ekscesivne erozije na ogoljenim fl išnim padinama u istri primjenom terestrične fotogrametrije.− hrvatske vode – časopis za vodno gospodarstvo, 38, 49−58. jurak, v., petraš, j., aljinović, d. & gajski, d. (2003): field intensity measurements of erosion instability in fl ysch deposits in istria, croatia.− geotechnical measurements and modeling. lisse netherlands: a.a. balkema publishers, 283−289. jurak, v., slovenec, d. & mileusnić, m. (2005): pretjerana erozija fl iša – slani potok.– excursion guide-book, 3rd croatian geological congress, zagreb, 51−55. jurak, v., slovenec, d. & mileusnić, m. (2006): excessive fl ysch erosion – slani potok.− field trip guidebook, mecc'06, zagreb, 48−51. jurković, i. (1959): pojave barita u hrvatskoj.− geol. vjesnik, 12, 115−124. magdalenić, z. (1972): sedimentologija fl iških naslaga srednje istre [sedimentology of central istria fl ysch deposits – in croatian].− acta geologica vii/2, prirodoslovna istraživanja, knjiga 39. marinčić, s. (1981): eocenski fl iš jadranskog pojasa [eocene fl ysch of adriatic area – in croatia].– geol. vjesnik, 34, 27−38. mileusnić, m., slovenec, d. & jurak, v. (2004): thenarditeeffl orescence indicating cause of the excessive fl ysch erosion, slani potok, croatia.− acta mineralogica-petrographica, abstract series, szeged, 75−75. peh, z., miko, s. & bukovec, d., (2003): the geochemical background in istrian soils.− natura croatica, 12/4, 195−232. šiftar, d. (1981): o kemizmu barita i o nekim okolnostima postanka baritnih ležišta gorskoga kotara i like [on the chemism of barite and on the some conditions of the barite deposit formation in gorski kotar and lika – in croatian].− geol. vjesnik, 34, 95−107. šušnjar, m., bukovac, j., nikler, l., crnolatac, i., milan, a., šikić, d., terry, r.d. & chilingar, g.v. (1955): summary of “concerning some additional aids in studying sedimentary formations” by shvetsov m.s.– journal of sedimentary petrology, 25, 229–234. tišljar, j. (2004): sedimentologija klastičnih i siliciklastičnih ta ložina.− institut za geološka istraživanja, zagreb, 426 p. geologia croatica 63/3geologia croatica 322 tunis, g. & venturini, s. (1992): evolution of the southern margin of the julian basin with emphasis on the megabeds and turbidites sequence of the southern julian prealps (ne italy).– geol. croat., 45, 127−150. vragović, m. & golub, lj. (1969): hornblenda andezit (porfi rit) gornjeg benkovca kod fužina, gorski kotar [hornblenda-andesite (porphyrite) from g. benkovac near fužine, gorski kotar – in croatian].– acta geol., 6 (prir. istraživanja. jazu zagreb, 46), 55–66. manuscript received december 21, 2009 revised manuscript accepted june 25, 2010 available online november 11, 2010 geol. croat. 50/2 1289 -2981 6 figs. 1 zagreb 1997 hydrogeological evaluation of water retaining properties of the kosinj reservoir (lika, croatia) ante pavicic key words: karst hydrogeology, karstification , water retaining, hydrogeological zoning, kosinj reservoir, lika, croatia. abstract constructi on of the kos inj reservoir was planned in a karst ter­ rain on the lower par! of the river lika. preceding slud ies of this area did not compl etely de fi ne the waler constraining clements of the ter­ rain, and therefore the more reliable kruscica reservoir was buill. fur­ ther studies were undertaken in order 10 evaluate in detail the terrain o f the wliicipalcd location of the dam impoundment at kosinj . due to the lithological homogeneity of the karst terrain, the s tudi es focused on tectonics and geomo rphology, wilh emphas is on karstification. terrain zoning was made on the basis of hydrogeo logical favourabi ­ lily for water rctaining in the reservoir. the vcl cbit hydrogeolog ical barrier innuences the general water run off in the hinterl and , as well as the depth and the direction of adva ncement of recent karsti ficati on processes . in the hinterland of the velebit barrier the karstifi cat ion is shallow, increases in depth to­ wards the sea, and is characterized by the zoned distribution of spri­ ngs, estavelles and ponors. th is concept played a major role in laler hydrogeological stud ies o f the proposed reservoir. 1. introduction the completion o r the krusciea reservoir with a vol ~ umc of 134 x 10(' m3 on the lika river did not sat isfy the needs for reservoir space, because the achieved volume is only 15% of the averagc annual recharge of the lika rive r (qmcan= 27.9 111 3 s· i ) . together the headwaters of the gacka and lika rive rs are utilized by the hydroelec~ trie plant he senj but, due to the shortage of wate r stor~ age space, a po rti on o f the high wate rs is d ischarged in to ponors, which in turn causes floodin g of the polje. in order to utili ze larger volumes of water and to el imi ~ nate flooding, studies which would enable the construc­ tion of the kosinj reservo ir with a vo lume of 433 mil­ lion 111 3 were co ntinued in 1972. th e upper course of the bako vac tributary lies in an es tave lle zone and, the refo re, this va lley will be separated by a dam from the lake. institute o f geology, sachsova 2, p.o. box 268, hr· ] 0000 zagreb, croatia. the waters from the bakovac tributary are to be di s~ charged int o the lika rive r through a tunnel down ~ stream from the lake and utilized in the he senj. during exploratory drilling , the rim o f the future reservoir, at the side of the lipovo polje, and the bound~ ary area by the gacka rive r were investi gated. the majority of the drilled holes contain equipment whi ch has produced water level data for over 30 years. recen­ tly drilled observation boreholes were a lso used for monitoring groundwater level variations. groundwater flow tracing tests were performed (from the easte rn side of the lake and in the bakovac valley) which enabled the expansion of flow data obtained in previous studies (rrom areas surrounding pazariste and studcnci). de tai ­ led geophysical studies were performed in areas where injection barriers were planned and the narrow locati ons where damming was to be perfol111ed. to perform these rather co mplex studies, a large volume of varied data, from both published papers and proress ional studies was required. the fund amental publi shed papers were the result of studies done during the construction of the kruscica artificial lake. bahun (1962) dcscribed in deta il the lithological composition o f the rocks, with emphasis on the l elar beds. the same author (bahun, 1973), re lated the karst processcs and fluvial e ros ion in the l ika ri ver area and gives an acco unt o f karstificat ion phases. on the bas is o r data from the region surrounding the mtificial kruscica lake, pavlln (1970) delineated a ponor zone. an es tavelle zone and a spring zone. pavich: (1984) also included a large part of th is area when dealing with the velebit groundwater divide. bah un & fritz (1975) stud ied the hydrogeological features of the lelar beds, while fr itz & pavich': (197 5) and pavicic & fritz (1976) outlined in deta il c re taceous beds and the l e lar beds, dete rmined num erous fault s in the area anci described the hydrogeological re lationsh ips in the lower course of the lika river. prelogovic (1989) descri ­ bed the neotectonic movements in the area of northern velebit and a part of lika and provided new insight to the structu ral and tectonic re lat ionships. the da ta 0 11 the th is paper was presented at the scientific meeting: dedicated to the 80th a nniversary of the life of professor mi lan herak, held on march 5th, 1997 in zagreb origin of structures and faults and neotectonics enabled bette r interpretation of the hydrogeological relation­ ships and groundwaler flow. pa vici<': (1995) in hi s phd lhesis described the hydrogeological condilions for the construction of water reservoirs in the karst of the vclebil hinleriand , where he also sludied the area around kosinj . and thi s was used as the basis for the present paper. 2. hydrogeological relationships in the kosinj reservoir area 2.1. hydrogeological properties of rocks on the hydrogeological map presenled in fig. 2 lhe main lithostratigraphic members outlined are grouped by lhe ir hydrogeological properties. in the studied recharge area triassic. jurassic, cretaceous and lower palaeogene carbonate rocks dominate. the rocks are divided into five groups according to the ir permeability. the limestones in alternation with dolomites and limestone breccia (t; , j, k ,) are very permeable rocks. partly impenmeable are the jelar beds (pg2,,), while the dolom ites (tj) are part ly permeable. the shales and sandstone (t " t ;) and tuff and tuffite veoiogm \..roallcii ' vi/. fig. 1 kosinj reservoir layout. legend: i ) kosinj rcsclvoir: 2) kosinj dam and hpp: 3) sedlo dam: 4) bakovac dam: 5) skl ­ ope dam and hpp; 6) krusc ica rese rvoir; 7) bakovac lika tunnel; 8) bakovac lika e1la­ nnel; 9) se ji ste compcnsat ion basin. are impermeable. the quaternary deposits are mainly represented by colluvial beds, deposited in the poljes, and their relics can be found on elevated surfaces of the terrain. these clay-silty deposits ean be very thick and impermeable in some areas, allowing surface water flow in the polje where the groundwater level is below the water bed (e.g. lipovo polje). 2.2. tectonic basis of hydrogeological conditions almost all of the area studied belongs to the dinar­ icum megastructural unit (herak, 1986, 1991). the geodynamics of the studied area is characterized by structures resulting from foldin g and faulting which occurred after deposition of the eocene flysch deposits. these movements defined the existing structures, which are outlined by regional fault s which are often accom ­ panied by the jelar beds (bahun, 1974, 1984; her­ ak & bah un, 1980). thesc tectonic structures were formed during the upper oligocene and miocene, prin­ cipally by tangential movements (bahun, 1974; prelogovic, 1989). the final phase of these move­ ment s occurred in the upper pliocene and the quater­ nary when transcurrent faults were active and were par­ ticularly intensive in the vclebit region. the neotecto­ nic movements have influenced recent karstificati on pavicic: i-iydrogeological evaluation of water retaining propenies of the kosinj reservoir (lib, croatia) 29 1 ~ i -2 3 • 4 0 5 <> • 8 7 ,(? 8 ~ 9 d'o ~11 s" em3313 i ii " 0"",=",,,,_=,,-,,5'0 j fig. 2 general hydrogeo logical map. legend: 1) geo logical boundary; 2) fault; 3) assumed direclion of g roundwater discharge; 4) permancnt karsi spring; 5) intermittent karst spring; 6) intermittent coaslal sp ring; 7) swallow hole (ponor); 8) submarine spring (vrulja); 9) defined underground connecti on betwccn a ponor and a spring; 10) permeable zone; ii ) velebit hydrogeological baltier; 12) partly impcrmeable rocks; 13) partly pcrmeable rocks; 14) impcnncable rocks. and recent water now patterns. although the prevailing geological structures in the studied area are governed by deep tangential and reverse tectonics, the hydrogeo­ logical conditions can be interpreted main ly from sur­ face outlines of the structures. alternatively, the water dynamics of the studied area is confined to relati vely sha llow parts of the terrain, well above the conlact between megas lructu ra l unit s, so the deep langent ial lectonics has no influence on water emergence and flow. on the basis of the geology of the studied area and the basic tectonics involved, distinctive areas. structural units and fault s that inlluencc the hydrogeology of the terrajn arc presented in fig. 3. the velebi t mountain range form s (he south-west­ ern limb of an extensive regional fo ld (bahun, 1974) thrusted durin g the first phase, and later disintegrated by radial neoleelonics. tn the core of the anticline, alo­ ng the fault on the edge of licko poljc, to the west from the water accumu lations kruscica and kosinj , outcrops of pal aeozoi c and lowe r triassic, and to a lesser de­ gree middle triassic impemleable clast ic rocks occur. the posi tion of these impenneable rocks in the velebit massif, the uplift of which began after the miocene and co ncluded in the upper pliocene and the quaternary (prelogoyi c, 1989), influenced the hydrogeological conditions in the hinterland , especially as reflected in the direction of kars tification and the groundwater level in the area of recharge surrounding the water reservoirs. the occurrence of neogene marls in a deep sinkhole (borehole k-4-2, fig. 4) confirms the existence of vcry young fau lt tectoni cs . the thi ckening marl and mor­ phology of the lerrain indicate a throw along the fault plane of over 100 ill. the fau lts, iogether with the struclural and lithologi­ ca l features of the rocks, are the most important e le­ ments that influe nce the karstification process and groundwater flo w in karsl terrai ns, as first stressed by herak (1957). more recent studies (fr itz, 1972, 199 1, 1992; fritz & payicic, 1986; bai-iun & fritz, 1987) suggest that the principal influence is that of recent karstifi cation , which is assoc iated with the youngesl neotectonic fault s. during map e labora­ tion, the data from studies of the northern ve lebit and parts oflika (prelogovic, 1989) was used. as a consequence of regional tangential stress, com­ press ion faults occur within smaller or larger areas. these are usually manifesled as hinge, transcurrent and reverse faults. tension fault s, that occur as fi ssures par­ allel with the principal stress direction, havc the least pronounced strike displacement, and they are con fin ed to smaller areas, usually within tectonic blocks. they are important for local groundwater flow conditions. the transcurrenl fault s are of primary importance in groundwater flow , since the rocks in which they occu r are compressed, and thus can act as a barrier 10 ground­ water flow perpendicular to the fault plane. the gro­ undwater flow is directed parallel to the fault plane, and 292 " '" 9 • 10 natural re tention can occur on the upstream side of the fault. this group of fa ults is represented by the vra­ tnik senjsko bilo peru sic fault on the eastern margin of the senjsko bilo krasno structural unit , and the lika fault , west of the studied water reservoir locations. these faults are characterized by groundwater flow par­ allel to the fault plane, while groundwater flow perpen­ dicular to the fault plane is of a lower degree, parlieum q.s.1. a 20' 600 0 0 00 0 o 0 ~ 00 o 0 0 0 550 o 00 0 0 000 0°0 00 0 00 0 0 0°°0 0 5 do oopg 23oo o 0 ~ do 000 000 00 00° "0 b ~ /,. 100 100 300 400m , , fig.4 cross-section through the borehole k-4-2, showing the posi­ tion of the neogene marls. 6 <> eiill imnmij 2 ia,c~ 3 geologia croatica 5u/2 fig. 3 map showing the tectonic structure and hydrogeological function of the terrain. legend: § 4 ~ 5 j) velebit hydrogeological bar­ rier; 2) apatisan relative barrier: 3) hydrogeological zones: a spring zone, b estavelle zone, c ponor zone; 4) nonnal fau ll : 5) reverse fault; 6) anticline axis; 7) permanent karst spring; 8) intermittent karst spring: 9) estavelle; 10) permanent coastal spri ng; 11) intermittent coastal spring; 12) submarine spring; 13 swallow hole (ponor). • 7 " 8 11 vo 12 0 13 lady in recently active fault zones. the neotectonic active faults in the area of northern velebit are vertical to very steep wi1h a wnw-ese strike. 2.3 hydrogeological functions of the terrain the hydrogeological functions of the studied terrain were determined on the basis of the hydrogeological features of rocks, tectonics, and the spatial distribution and relative positions of gcological bodies and their morphology. in the studied area the following hydroge­ ological functions of different parts of the terrain were determined: futl barriers, partial barriers and permeable areas. 2.3.1 hydrogeological barriers barriers can be classified according to the degree that they obstruct water flow as full or partial (relative) baltiers. in the stud ied area the principal hydrogeological feature is the velebit full barrier which extends from the bakovae valley to 1hc stikadsko polje (fig. 3). the str ike of this barrier is confined within the velebit structural unit. the existence of this barrier is deter­ mined by impermeable palaeozoic and lower triassic deposits the e levat ion of which is much higher than the pavicit: i lydrogeological evaluation of water retaining prope rties of the kosinj reservoir (uk;!, croatia) 293 m (0 s i) 1000 ., 500 ) m (0 s i) 1000., younger wurm 1580 older holocene <>-+--<> jama (ha((>1 river l iko present m (0 s i) 1000 zone of sinkholes krce'vine zl vuljo zone of i nte rmit~ 5pring5 (""""j" z 0 n e of spr'ngs ern a vr(>fo kosinjski koslnjsko polle : lokv/co a6 bmovac groundwater level in the licko polje. the impemleable middle triassic pyrocl astic rocks also supplement the hyd rogeo logica l barrier in the area to west from pazariste. this part of the velcbit structure is an impcr­ meab le barrier wh ich cannot be penetrated either by surface or g round water from the hinterland. it forces the waters to flow ei ther in an eastward and south-east­ ward d irect ion or northward and north-eastward. the function of the velebit barrier as a full barrier is not diminished by the occurrence o r permeable middle triass ic deposits, because the loss of water is confined with in the penneable rocks, and the occurrence of deep karst forms, such as jamas (karst shans), is only local. the upper tri ass ic clas tic rocks and dolomites pre­ scnt in arcas where no tectonic di sruption occurred , aet as hangi ng barriers with in a full barrier. anot her partial barrier is the apat isan anticline sit u· ated wi thi n the senjsko bilo structural unit , wherc the li assic dcposits in the core of the antic line rcduce the fl oor and alter the direction of groundwater flow , which result s in relatively hi gh groundwat er level s in the lipovo polje and the occurrence of intermittent springs and nooding. river l/ko fig. 5 deve lopm ent of the bako· vac valley and wat er dminage. legend: i) pe rmanent s urface discharge into the likil river; 2) intermittent surface diseha· rgc into lhe uka river; 3) gro­ undwater discharge; 4) grou­ ndwater level: 5) zonal wa te r di vide: 6) remains of a terrace; 7) observ<ltion boreholc . 2.3.2 permeable areas the permeable areas mainly consist of highl y per­ meable carbonate depos its. due to tectonic activity, the­ se rocks have been fractured and suffered later karstica­ lion. due to the positi ve hydrogeo log ical fun ction or the velebit massif, particularly in the hinterland or the velebit barrier the kars ti fication in the lika rcgion occms at relatively shallow depths. in the permeable terrain , an arca with minimal gro­ undwat er levels above the surface water flow of the rivers lika and gacka (these are al so the local erosion base levcls area a in fig. 3), was delimited from thc parts of the terrain whcre the ground water leve ls are lower than the surface ri ver beds, so that the watcr from these areas drains to the coastal springs and subm arine springs through the undcrgrou nd (area c, fig. 3). in the carbonate terrains (li mestones and li mestone breccia) with the minimal groundwater levels above the watcr icvel of the ri vers (arca 5, fig. 6), the river water flow is permanent. waters from adjacent terrains drain towards the rivers, both underground and on the surfa­ ce, in the same direc tion during the periods of both high j.'jq geologia croallca 50(.l d ---6 witj • 7 2 '" 8 d 3 g 9 ~ ". 4 0 it] 5 01(·1) 1 " 1 -52013 -48014 -_5'0 __ 15 --"-"16 ~ 17 a 20 ~ 18 o 1000 2000"1 ... _ ..j .... ... ............ > •• l----=:j fig. 6 hydrogeological zon ing of permeable areas. legend: i) grou nd water above the lika river stage: 2) jehu deposits impenneablc as a unit; 3) rclative ly uplifled tcctonic block; 4) terrain under a highcr influence of clay deposi ts; 5) low groundwatcr under lika river: 6) faul l; 7) major karst spri ng. pennanent; 8) major karst spring. inte rmittent; 9) permanen t karst spring. di scharge less than i l/s: 10) estavejle; ii) swallow hole (ponor); 12) observation exploratory borehole; 13) wate r table contour line (mainly low water); 14) assumed boundary of ihe arca without vertica l leakage; 15) boundary of the area where groundwater is above 540 m a.s.l. during the rainy season; 16) water divide between the lib and gacka rivcrs; 17) local water divide; 18) groundw,llcr flow dircction; 19) detennincd underground hyd raulic conne· clion (belween a ponor and a spri ng); 20) kosinj reservoir. and low flow. along these river valleys permanent and intermiltent springs ex ist, but es tavelles and ponors are absen t. the watcr div idc in this region is shown in fig. 6. the water divide between the lika and gacka rivers is confirmed by the exis tence of numerous springs alo­ ng the eastern bank of the lika river and by the ground­ water levels in the boreholes. the permeable zone, that is drained towards the sea, incorpo rates the area of es tavcllcs from the bakovac valley, through the lipovo polje to the gaeka river (ar­ ea b in fig. 3). the main features of this area are the exis tence of ponors and es tavelles, and rarely some intermittent springs of low discharge rate. the gacka and lika rivers in this part of the terrain have their lev­ els above groundwater levels for almost all of the year and arc considered as "hanging" surface-water streams. lower groundwater levels in this area are a conse­ quence of cessati on of the function of the velebit and apatisan barriers, and progradation of recent karstifica­ tion from the coast towards the hinterland. the estavelle zonc in the downstream direction passes into the ponor area. during all hydrological con­ dit ions, the groundwater level in the ponor area is con­ siderably lower than the stream that is sinking. more detailed zoning of thc karst terrain, and parti­ cularly the permeable areas a t the edge of the velebi t barrier was performed duri ng inves tigations for the kosinj water reservoir project. 2.4. karstification since the kosinj reservo ir recharge area is in a rela­ tively litho log ically homogeneous karst te rrain , an important element for the evaluation of reservoir water constrain ing capacity and reservoir feasi bility, arc the processes of tectonism and karsti fication. the geolog i­ cal conditions in the studied terrain indicate, that before the neotectonic uplift which preceded the forming of the current landscape, several emersion events occurred in the dinarides. the first favo urable conditions for karstification occurred in the dinaride area after f'ly sch deposition, when, during the pyrenean orogeny, large masses of carbonate rocks were exposed to exogenous processes . during this orogenic event , the clas tic-car­ bonate l elar beds were form ed in the lika region. the mol asse characteristics of these sediments indicate that the flattening and erasing of the elevated landscape was contemporaneo us with their [ormation (ba hun , 1990). pav icic: ilydrogcological baluation of water ret;lin ing properties of the kosinj reservoir (lika, croalia) 295 the ncotcctonic movements which commenced in the miocene and were intensified toward the end of pli ocene and the beginning of pleistocene played a major ro le in the reshaping of the land scape and the developmelll of karstirication. velebit was then uplifted together with other mountain ranges, whi le depressions developed as isolated karst plateaux and poljes. in somc deprcss ions, deposition of plio-quaternary sediments occu rred, the remnants of which are round in sevcral rccent depress ions and karst poljes. the neotectoni c movement s changed not only the shape of the land­ scape but also influenced the change of groundwatcr drainagc th rough previously form cd channels and cavi­ ties. the links bctween the subsurface channels wcre cut , and so mc water-bearing cavities were scparated from the new ly form ed ground water dynamics. the principal drainage d ircction from the velebit hinterland towards the adriat ic basin was preserved, but the local erosion base levels changed. together wi th the upli ft of velcbit the impenn eablc palaeozoic and lower triassic deposi ts were also raised closer 10 the surfacc, resulting in their action as a hydrogeological barrier to the south of the bakovac fa ult from the time of uplift un til the prcsen t. to the north of the bakovac fault , the imper­ mea bl e rocks lie deeper beneath thc surface, enabling deeper karstification and groundwater drainage from the velebit karst hinterland towards the adriatic sea. the dept h of karstification in the lika region , (man­ ifested in the ex istance and depth of spclacolog ical phe­ nomena), the groundwater level conditions, the occur­ rence or ponors, estavelles, intermittent and permancn t springs and their zoned d ist ribthion , are the conse­ qucnccs of thc positive role of the velebit hydrogeolo­ gica l barrier. the karstification process generally pro­ gresses from the sca towards the hinterland. in the ilear hinte rl and of the velebit barrier, the current eros ion base levels are thc li ka river and the secti on of gacka river th at is upstream from the zone of permanent springs. the depth of rcccnt karstification is approxi­ mately the same as the depth of the rivcr beds, towards which grou ndwater drainage occurs. only small local variations ca n occur as a conscqucncc of the most reccnt movements of tcctonic blocks. karstifi cation deeper than the level of the river bed in the area under thc influence of the velebil barrier is linkcd to an earl i­ e r phase of karstification. thi s was determined in the area of the krllscica rcservoi r, whcre at a depth of 250 111 be low the level of the river bed, caverns fill ed with quartz sand were cncountered during exploration dril ­ ling. t hese finding s indicate that these deep cave rns were once a part of the ground water dynamics. the subsurface cav iti es and channels, developed in earlier phases of karstificati on, locally can be " inherited" into the complex underground systcm s. however, for th e interpretation of current hydrogeological conditions, the landscape and karstification arc a conscquence of exo­ dynamic processes that were active in the pl eistocene and holoce ne, and where the eros ion base level s are ri vers (lika and gacka) or the sca. to evaluate water retention potential of a rcservoir in karst terrains, it is of prime im portance that the study of landscape develop­ ment and karstification is pe rform ed (fritz, 1992). recent studies performed in the dinaric karst terrains indicate that the present landscape is very young. the majolity of river valleys and lake depressions were cre­ ated during the lower pleistocene and holocene. the analysis of landscape development and karstifi ­ cation processes is performed through the study of river va tteys. the analysis involves not only the relationship between the valleys and thc clcvated surrou ndings in a karst environment, but also utili zes the dat a on hydro­ logical characteristics, the occurrence of springs and ponors and the water-leve l flu ctuations in the terrain through which the river nows. the most abundant data, that can be used for analysis of landscape developmcnt and karstification, is available for the a reas of the licko-gracac plateau, the lika river and the bakovac valley, while correlation is poss ible with the sou thern part of velebit in the area surrou nding the cave area cerovacke pecine. in the lipovo polje , the lika ri vcr bed partly cuts through quaternary sediment s. arter thi s incision , ncw terraces were not form ed. the left ridge of the valley , upstream from thc hydroe lec tric plant sklope, consists of plio-quaternary marl s, over­ lain by pleistocene colluvial clays, which were deposi ­ ted both in the kosinjsko and lipovo polje. along the river banks, intermittent and pcrmanent springs occur, with no noticeable water loss , and the g roundwater lev­ els are higher in the banks than in the river bed. the stream in the bakovac valley, (the nort hern tributary of lika river), cuts through triass ic and juras­ sic depos its in its upper course, and in its mi dd le and lower course through the l elar beds. in the va lley, depo­ sition of pleistocene and holocene sed iments of various genetic types took place. tn the hi gher part of the val­ ley, rem nants of loose moraine materi al and so lid bed­ ded fluvi oglacial cong lomerates can be found. on thc va ll ey slopes and the valley fl oor collu vial clays were deposi ted. on the basis of relatively small patches of quater­ nary deposits preserved in the higher pan of thc bako­ vac valley and velebit, it can be concluded that valley incision occurred in two phases . the incis ion of a rela­ ti vely shallow valley occurred before the deposition of riuviogiac ial conglomerales which are preserved in the area of krcevine at 720-780 m a.s.!. in the highest pan of the valley on the slopes of velebit , moraine material is preserved. the downstream part of the valley was at that period cither deeper, or was lowcred along a youj1 ger diagona l fault in the area downstream from the zivulje spring. in this part of the va lley, flu viog lacial conglomerates arc situated at an elevation of 580 m a.s.!. during deposition of colluvi al clays in the broader area of the lika plateau, thc bakovac vall ey was co n­ siderably shallower than today. the association of bakovac valley deve lopment with the evolution of the lika plateau and the canyon inc is ion of the lika river, is the consequence of the 296 function of the velebit hydrogeological barrier (fig. 3). the bakovac valley is situated at the edge of influence of the velebit full barrie r, i.e. on the boundary towards northern velebit and senjsko bilo. in this region , the karstification is much deeper and the waters drain towa­ rds the sea. the progression of deep karstification deve­ lops from the sea towards the mainland in the lika region through the bakovac valley, and on through to the lower cou rse of the lika ri vcr, and then into the lipovo poljc and the periphery of kosinjsko polje. the progression of the karstification process is manifes ted in chan ges of stream flow patcrns, the occurrence of intermittent sprin gs, the presence of estavclles and panors, and an increase of depth to groundwate r. the advance of thc karstification process from thc sea to the hinterland has affected the bakovac valley in its higher and middle parts. as a resu lt, part of the wa­ ter drains beneath the valley floor through its northern side directly into the sea . during heavy rainfall, when water flows in the stream bed through the middle part of the bakovac valley, the groundwater level there is below the valley floor. from the activity of this ponor, it can be concluded that the groundwater level there is always below the stream bed, which was confirmed with measurements performed in the observation bore­ holc a-8. the spclaeological phenomena situated along the middle and lower course of the lika river, and the regi­ on between the lika and gacka rivers occur at shalow depths (bozicev ic, 1965, 1969) which corresponds to the relatively high erosional base level encounte red therc. this is a resu lt of the function of the velebit full barrier. the development of the karstification process can also be viewed in terms of sufficient sinking of the paleoplateau on the southeastern part of the velebit bar­ rier, in the cave area cerovacke peeine along the south­ ern cdgc of the graeacko polje (malez, 1965). 3. general conditions for the construction of the kosinj reservoir the construction of the kosinj reservoir is planned for part of the lower course of the lika river. the dam is to be built some 800 m upst ream from the bridge (kosinjski most), in fact downstream from the existing reservoi r kruscica. in order to dete rmine the hydrogeological condi­ tions that would allow the feasibility of reservoir con­ struction, the area downstream from the reservoir "kruscica" in the valley of lika river was also studied, as we ll as the broader area of reservoir recharge towards the bakovac valley, lipovo polje and the boun­ dary zone towards the gacka river. detailed hydrogeo­ logical mapping was performed on a scale of i :5,000 of the local area and the margins of the reservoir. a better understanding of tectonic conditions of both the imme­ diate and broader regions of reservoir recharge was enhanced by neotectonic studies of the same area (prelogovic, 1989). geologia cro;llica 50/2 extensive exploration drilling was performed, acco­ mpani ed by permeability measurements, geophysical tests, and water tracing tests. the grou ndwater level monitoring was conducted for many years, in over 50 observation boreholes in the recharge area of the future reservoir. in the groundwater-level studies, data were used [rom observation and other exploralion boreholes made during the elaboration of the kruscica reservoir. the kosinj reservoir area mainly consists of pennc­ able cretaceous carbonate rocks and the jelar beds, so it is a hydrogeologically homogeneous terrain . there­ fore, the hydrogeological conditions and water retaining characteristics are explained by zoning of the broader region surrounding the reservoir, according to the hyd­ rogeological functions of the terrain (fig. 3). the velebit hydrogeological barrier prevented dee­ per karstification of the transition region, which is refle­ cted by high g roundwater levels and the drainage of water towards the lika river. outside the area of barrier influence, ponors and estavclles exist, and the streams are in tennittent or "hang" above the deeper groundwa­ ter levels. under these conditions, in order to perform the studies, to evaluate the permeability of the broader area, and to plan the necessary intervening procedures, detailed hydrogeological zoning of the terrain recharg­ ing the reservoir (fig. 6) was performed. the following [our zones with unique hydrogeological features were outlined: the area with permeable surface conditions and groundwater above the water level of the lika river (1) covers a large part of the kosinj reservoir bollom su rface. all the waters in this zone flow towards the lika river. along the stream bed of the lika river and its tributaries bakovac and mlakvenski potok, several permanent and intcrmittent springs exist. tn this part of the terrain, only one ponor exists which drains the waters from the mlakvenski potok. the tracing tests, performed in the borehole lg-5 on the northern bank of the reservoir, indirectly proved that the water of mlak­ venski potok drains through ponomc into the lika river. in the terrain within this zone, all the waters either drain towards the lika or gaeka rivers. the impermeable jelar beds (2) arc situated in the southwestern part of the terrain on which the kruscica reservoir lies. the lelar beds in this part of the terrain contain breccia with clayey marl cement and lenses of marl. the water retaining characteristics of the krus­ cica reservoir is attributed to the favourable hydrogeo­ logical features of th~se deposits. the zone of the uplifted tectonic block and the terrain under the larger influence of the now eroded neogene clay deposits (3) on the map showing hyd­ rogeological provinces, this area is situated in the mid­ dle part, and the eastern margin of the kosinj reservoir. this is also the water divide between the lika and gac~ ka rivers. the existence of this water divide is the con­ sequence of the uplifted tectonic block mlakvena greda poijan, where reccnt karstification is fairly l'avicic: il ydrogeologic:ii ev3lu:liion of w:uer rel3ining propcn ics oflhe kosinj reservoir (lib. emalia) 297 shallow. the occurre nce of neogene marl deposits in fossi l depress ions, found in boreholes k-4-2 and k-9, has a certain impermeable role in this terrain. the boreholes revealed fi ss ures and cavities con­ taining compressed clay, a feature also indicated by the geophys ica l exploration performed a long the route of the planned grout curtain. spelaeological phenomena in thi s zone occur at relat ively shallow depth and are above the kosinj reservoir backwater level the groundwater level measurement s performed in the dri ll hole over a longcr period showcd that the gro­ undwater leve ls alo ng the watcr divide towards the gaeka ri ver do not fall bellow 520 m a.s.l. (fig. 6). the precise position o r the water divide was de tennincd by traci ng or water drainagc from the dr ill holes. the area in which the low waters are below the lika river stream flow, and the erosion base level is the adriatic sea (4) occupies the te rrain north and northwcst from the kosinj reservoir. downstream from the kosinj dam is the lipovo polj e and it s recharge zone. in the upstream part of the lipovo polje on its eastern and western slopes a st ring o r intermittent spri­ ngs and cs tave tles exisi. ponors arc located in the downstream part or the polje and, through them, water from the lika rivcr drains to the sec. the estavelle zone during the d ry season "passes" from the upstream part o r the lipovo polje into the area of the kosinj reservoir. the groundwater level decline below the level or the lika ri ver stream bed was observed o n the wes tern bank be tween thc lipovo polje and kosinj sko polj e, where the 480 m watertable contour enters the area of the reservo ir. nca r the borehol e bk-4, the boundary between the sp ring zone and the estavelle zone is close to the reservoir. the groundwater leve l dec line in this reservoir bank was also observed in the borehole bk-2. in the bakovac va lley this boundary is upstream from the position of the dam. hydrogeological zoning (fig. 6) is the basis for ihe understanding of hydrogeo logical co nditi ons and the eval uation or the water retaining properties of the kos­ inj reservoir; it a lso allowed the separation of imperme­ ab le areas from the permeable ones, the definition of locations for the construction of dams and the identifi­ cation of banks which have to be made impermeable by grouting. furlher studies (drilling exploration, geophys ical exploration, detailed study of neogene marls in depres­ sions on the east reservoir bank) should more precisely determ ine the conditions that will enab le the constru­ ct ion of the reservoi r, i.e. produce the da ta necessary for the construct ion of the grout curtain. 4. conclusion the necessa ry studies performed for the constru ­ ction of a suffic iently impermeable reservoir in a karst terrain, for a big hydroelectric plant , arc presented throug h the results obtained in the case of the kosinj reservoir. the reservoir is situated in te rrain composed or penneable limestone and limestone breccia (c reta­ ceous and l e lar deposit s). the karst terrain in the hin­ te rland of the velebit barrier is divided int o a spring lone, an estavelle zone and a ponor zone. because the location of the kosinj reservoi r is almos t com ple te ly situated within the spring zone, a basis for further st ud­ ies exists, although this location was prev iou sly reje­ cted . the homogeneous karst terrain, largely composed of mass ive lelar deposits with relatively undefined re la­ tionships with the cre taceolls deposits , requ ired a spe­ cific approach, so the studies were focu sed on the struc­ tural and tectonic setting, the landscape development and the karstification processes. in order to evaluate the permeability of the broader area and to plan the necessary intervening procedures, detailed hydrogeological zoning in the area or reservoir influcnce was performed and several zones with similar hydrogeological features were out lined. from the explorati on boreholes it was poss ib le to obtain the data about groundwater levels, the character and depth of karstification. by groundwater traci ng, the flow directions and the positions of groundwater divides were defined. the bakovac valley development is associated with the incision of the lika river into the lika plateau as a continuou s process of the recent karstifi cat ion. thi s karstifica tion incorporates the spelaeological phenome­ na situated along the kruscica dam and in the region between the lika and gaeka ri vers. t he perfo rmed studies confirmed the ex istence of karst ification bene­ ath the lika riverbed (the river is incised int o a previ­ o usly karstified ter rain). neve rtheless, thi s docs no t dimini sh the hydrogeological importance of th e lika river as a recent erosional base level, because the o lder subsurrace systems and groundwate r flows were inter­ rupted by neotec tonics, or because the dra inage chan­ nels arc clogged with c lay mate rial. the results of the studies confirmed that the recent karstifica tion , with which the present water dynami cs is assoc iated, is relat ively shallow in the kosinj reservoir area. therefore, it is poss ible to achieve an impermea­ ble reservoir with the aid of addit ional co nstruct ion work. 5. references bah un, s. (1962): vapnenei promina-nas laga 1i pod­ rucju kruscice u lic! (limestones in thc prom ina deposi ts of the te rritory of krusc ica in lika.).­ geo /. vjesnik, 15/1 , 101 -106. bah un. s. (1973): odnos krskog proeesa i ollvijalnc erozije u poclrucju like (relationship between kars­ tifi cation and fluvi atil e erosi on in the reg ion of lika, cenlral croatia).krs jligos/. , 8/5, 91 100, zagreb. 298 bahun, s. ( 1974): tcktogencza vclebita i postanak jelar· naslaga (the tectogenesis of mt. velebit and the formation of l e lar deposils) .oeol. vjesnik, 27, 35·51, bahun, s. (1984): tectonic and hydrogeological sig· nificance of the areas composed of the lelar forma­ tion (tektonsko i hidrogeo!osko znacenje podrucja izgradenih od jelar· fonnacija). · krs jugosl. , 11/1, 1· 11, zagreb. bahun, s. (1990): stupnjevi razvoja zaravni u dinar· skorn krsu (stages of formation of the plains in the dinaric karst).· krs jugosl. 12/6, 147·158, zagreb. bahun, s. & fritz, f. (1975): hidrogeoloske speci· ficnosti jelar-naslaga (hydrogeolog ical properties of jelar deposits, lika, croatia.).· geol. vjesnik, 28, 345· 355. bai-tun, s. & fritz, f. (1987): postanak izvora u d in arskom orogenskom akumuliranom krsu (the origin of springs in dinaric orogenic acc umulated karsl.) . krs jugosl. 12/2,27·37, zagreb. bozicevic, s. (1965): poljakova pecina.· geol. vjes· nik, 18/1, 141·157. bozicev ic, s. (1969): horvatova pecina uz branu sklope (the horvat cave at the slope dam). · geol. vjesnik, 22, 501·510. fritz, f. (1972): razvitak gornjeg toka rijeke zrman· jc (morpholog ica l evolution of the upper zrmanja course).· krs jugosl., 8, 1· 16, zagreb, fritz, f. (1991): utjeeaj reeentnog okrsavanja na zah· vacanje voda (the influence of the recent karst ifica­ tion on water cxtraction).geol. vjesnik, 44, 281288. fritz, f. (1992): effect of recent sea level change on the development o f karst phcnomena. proc. intern. symp. "geomorphology and sea" and meeting geo­ morpho comm. carpatho-balcan countries, mali losinj, 85-92, zagreb. fritz, f. & pavicic, a. ( 1975): tektonski odnosi u podrucju razvoja krednih i je lar nas laga kod kosi ­ nja u lici (tectonical pattern o[ cretaceous and je l­ ar depos its at kosinj , lika, croatia).geo!. vjesnik, 28, 35-42. fritz, f. & pavicic, a. (1987): 0 problemu zastit· nih zona u krsu primjer problematike zastite izvora geolog ia croatica 50/2 jadro.zast ita izvorista voda za vodoopskrbu, 255262, split. herak, m. (1957): geoloska osnova nekih hidrolo· skih pojava u dinarskom krsu (gcologischc grundla­ gen e iniger hydrogeologischen erschinungen in dinarisehen karst).· ii. kongr. geo!. jugos !. , 523· 539, sarajevo. herak, m. (1986): a new concept of geotectonics of the dinarides.· acta geol, 16/1, 1-42, zagreb. herak, m. ( 1991): dinaridi. mobilistieki osvrr na genezu i strukturu (dinarides. mobilistic view of the genesis and strukrure).· acta geol, 2 1/2, 35· 117, zagreb. herak, m. & bah un, s. (1980): the role of the eal· carous breccias (je lar-formalion) in the tectonic interpretation of the hi gh karst zonc of thc dinar­ ides. · geol vjesnik, 31, 49·59. malez, m. (1965): cerovaeke peci ne (d ie hohlen von cerovac) .spe leol. drustvo hrvat ske, 1, 1-44, zagreb. pa vicic, a. (1984): geoloska osnoya veicbi tske raz· vodnice (geological foundation of the vele bit waler div ide, croalia).8 . jugos!. s imp. hidrogeol. in z . geol, 1,537·547, budya. pavicic, a. ( 1995): hidrogeoloski uvjeti za ostyare· nje akumulacije u krsu zaleda velebita (hydrogeo· logical conditions [or the construction of reservoirs in the velebit ml. hinterland, croatia).· unpub· lished phd thesis, university of zagreb, 113 p. pa vicic, a. & fritz, f. ( 1976): l-lidrogeologija sir· eg podrueja donjeg toka like (pazariste, krs, otoeae) (hydrogeology of the lower lika river region (pazariste krs otocac». 4. jugos!. simp. hidrogeol inz. geol, 1,291·304, skopje. pavlln, b. (1970): kruseica storage basin in the cav· ernous karst area.comision intcrnational e des grandes barrages . dixi eme congres des grands barrages, 209·224, montreal prelogovic, e. (1989): neotektonski pokreti u pod· rucju sjevernog velebita i dijela likc.geol. vjes­ nik,42, 133· 147 . manuscript received april 14, 1997. revised manuscript acccpted november 10, 1997. geo.cro.2-3-61-kb.pdf 239 � marc a. conrad1 and bernard clavel2 ab stra ct sediment binding crusts of lithocodium aggregatum and associated bacinella irregularis abound in a shallow water limestone layer, in south–east france. the sudden appearance of these crusts denotes a local, conspicuous change in an otherwise balanced, open marine depositional environment. based on regional correlation, the layer belongs to the lower hauterivian, ligatus zone, directly dated by an assemblage of orbitolinid foraminifera, and indirectly by a specimen of ammonite. it is older than the faraoni oceanic anoxic event (oae), (latest hauterivian, angulicostata auct. zone), and presumably not linked with a global climate change. two facies are recognized: (1) lithocodium bindstone, with bacinella, other microencrusters, and fl uorescent automicrite of microbial origin; (2) fl oatstones containing numerous fragments of lithocodium and accompanying biota. coarse rhombohedral dolomite is locally present. two modern analogues of microbial mediation are put forward to explain the lithocodium event: (a) lagoa vermelha, in brazil, along with anoxic, marginal marine conditions; (b) highborne cay, in the bahamas, along with oxic, open marine conditions. a stack of four upper hauterivian parasequences is described: parasequence 1 ends with oolitic deposits; the somewhat deeper water parasequence 2 occurs only in the south-eastern part of the study area, towards the subalpine depocenter; parasequence 3 matches the layer with lithocodium and bacinella, of variable thickness (0.8 m – 11 m), resulting from syn-sedimentary tectonic activity in the area of the vuache fault system which is a major feature; parasequence 4 corresponds with the resumption of the normal, urgonian carbonate factory. keywor ds: lithocodium, bacinella, urgonian, automicrite, dolomite, hauterivian, jura, pre-subalpine domain 1 71 chemin de planta, 1223 cologny, switzerland; (conrad@safemail.ch) 2 24 ch. des champs d’amot, 74140 messery, france a lithocodium and bacinella signature of a late hauterivian, local microbial event: the urgonian limestone in south-east france geologia croatica 61/2–3 239–250 6 figs. 1 pl. zagreb 2008 geologia croaticageologia croatica � 1. introduction lithocodium aggregatum elliott and bacinella irregularis radoičić are problematic, micro-encrusting calcareous organisms, which are either associated or found separately in the urgonian limestone. in the middle east, they are important components of certain hydrocarbon bearing carbonate reservoirs. extensive surface and subsurface studies were carried out to understand their habitat and depositional setting. the reader may refer to elliott (1963), banner et al. (1990), pascal (1979), koch et al. (2002), hillgaertner et al. (2003) and immenhauser et al. (2004, 2005). according to immenhauser et al. (2005), in oman, the lithocodium-bacinella association occurs with microbial-algal foraminiferal build-ups and bindstone facies corresponding to biologically out-of-balance communities. chemostrati gra phy shows that such intervals are coeval with the early aptian oceanic anoxic event oae1a (“livello selli”). they alternate with intervals dominated by rudist bivalves. the infl uence of nutrient gradients on carbonate platform community structures is considered the most likely model for the origin of the oman build-up episodes, (immenhauser et al. 2005, p 20). herein, an older (upper hauterivian) layer containing abundant lithocodium, bacinella and other micro-encrusters, is described from the margin of the urgonian platform, in southgeologia croatica geologia croatica 61/2–3 240 east france. the depositional setting matches a parasequence of bindstone layers, and/or the corresponding fragmented deposits. automicrite and idiomorphous dolomite are found, implying microbial mediation. here, the sequence stratigraphy, is locally applied to the lithocodium and bacinella layer, and interpreted and used as a dating tool by the present authors. more generally, the much debated issue of dating the urgonian limestone in south-east france and adjacent switzerland was recently reviewed by clavel et al. (2007), combining published and new biostratigraphic data from ammonites, echino ids, orbitolinids, dasycladalean algae, dinocysts and calcareous nannoplankton. 2. talus to platform margin transect in the northern french and swiss jura, the urgonian limestone consists of two informally defi ned formations: (1) the “urgonien jaune”, representing the fi rst (external) phase of the platform setting, dominated by heterotrophic organisms; (2) the “urgonien blanc”, essentially made up of platform interior deposits dominated by photo-autotrophic organisms. these designations, although commonly used, do not apply to the southern jura. the “urgonien jaune” and its equivalents are basal upper hauterivian. they are made up of reefal deposits of platform margin origin. rudists (pachytraga) are present in an interior, but still open marine setting. lithocodium and bacinella are absent from the “urgonien jaune”. the upper hauterivian pro parte to lower aptian pro parte “urgonien blanc” (or “urgonien s. str.”), extends from the jura to the subalpine domains. as shown by charollais et al. (2001), thick, prograding bioclastic deposits are present in the pre-subalpine and subalpine domains, marking the installation of the platform on top of hemipelagic deposits. vertically and laterally, they are followed by platform interior deposits with rudists (urgonian facies s. str,) extending as far as the swiss cantons of vaud and neuchâtel. the lithocodium and bacinella layer which is the subject of this article,only occurs in the french southern jura. it is described from fi ve fi eld sections and an additional outcrop depicted in fig. 2. oth er locations, not dealt with herein, occur in the valserine valley, north of bellegarde-sur-valserine, and on the vuache mountain, in a road cut described by blondel (1990). local correlations (fig. 4) roughly run from north to south, across the still active vuache fault system, a major tectonic feature known to be active since the mesozoic (charollais et al., 1983; donzeau et al., 1998). 2.1. platform talus, pre-subalpine domain – pic de l’oeillette section location (figs. 1, 3) is on the road between saint-laurent-dupont and saint-pierre-de-chartreuse (massif de la chartreuse, savoie), at lambert coord. 868.75/5027.15. the section was initially logged by arnaud-vanneau (1980). for dating elements and correlation with the nearby pas du frou section, see clavel et al. (2007). the echinoderm toxaster retusus and a specimen of plesiospitidiscus gr. ligatus (pl. i, fig. a), an index ammonite, was collected just below the urgonian limestone cliff. assemblages of orbitolinids (pl. i) including praedictyorbitolina busnardoi, p. claveli and p. carthusiana occur straddling the base of the urgonian cliff. the urgonian limestone consists of talus deposits: wackestones with echinoderm debris, sponge spicules, lenticulina sp. and small textularids, containing increasing admixtures of diverse, transported shallow water material including some oolites, bryozoan fi gu re 1: geological setting and upper hauterivian depositional environments, at the datum time shown in fig. 3 and 4. h: hemipelagic (basin s.l.). pm: platform margin and talus, shallow water, open marine. pi: platform interior, biotically restricted, with rudists; for details see clavel et al. (2007). palinspastic section: fig. 3. insert covering the extent of the layer with lithocodium and bacinella: fig. 4. geologia croaticamarc a. conrad and bernard clavel: a lithocodium and bacinella signature of a late hauterivian, local microbial event... 241 2.2. platform margin – mont de musièges section location (figs. 1, 3) is in the southern jura, in the haute-savoie, close to and on the sw side of the vuache fault-line. this section has also been studied by for example conrad (1969), charollais et al. (1989) and blanc-alétru (1995). four parasequences are logged at mont de musièges, on top of fl ooding surfaces showing no evidence of exposure. in the 10 m-thick parasequence 1, the transgressive tract contains up to 30% detrital quartz, bryozoan debris and an assemblage of foraminifera (lenticulina sp., small textularids, small miliolids etc.) denoting a typically deeper water environment, below the base of the euphotic zone. oolites prevail in the highstand tract. the 7 m-thick parasequence 2 extends on top of a nodular oolitic limestone, above a quite inconspicuous fl ooding boundary. the transgressive tract consists of weakly glauconitic, echinoderm lime grainstones and packstones. here also, the faunal content, with lenticulina sp., small textularids, small miliolids and bryozoan debris, typically stands for an open sea, deeper water environment of deposition. chert is present in the mid-part of the tract, indicating the maximum fl ooding interval. oolites appear higher up the section, in the highstand tract. debris, silicifi ed bivalves, annelids, corals, small gastropods, rare calcareous green algae (piriferella paucicalcarea, a dasycladale, boueina sp.), and foraminifera. lithocodium and bacinella debris are absent. fi gu re 2: fort de l’ecluse est (location fig. 4). 1: rock-solid oolitic limestone, at the top of parasequence 1; the deeper water parasequence 2 is missing. 3: brecciated, fossiliferous parasequence 3, matching the layer with lithocodium and bacinella. fi gu re 3: regional correlations and palinspastic profi le, from the talus to the margin of the urgonian platform. locations: fig. 1. datum time is upper hauterivian pro parte, ligatus ammonite zone. the distinction between the “urgonien jaune”, “marne de la russille” and “urgonien blanc” units applies to the vaud jura canton. the more general “urgonien s. str.” term applies to the southern jura and the pre-subalpine domain. for symbols, additional fi eld sections and close-up correlations in the southern jura see fig. 4. geologia croatica geologia croatica 61/2–3 242 plate i key ammonite and key orbitolinids plesiospitidiscus ligatus (d’orbigny) a 136.1, pic de l’oeillette praedictyorbitolina busnardoi schroeder et al. b 136.0-4, pic de l’oeillette c 136.0-3a, pic de l’oeillette g 6548a4, mont de musièges h 6548cb, mont de musièges. i 6548a1, mont de musièges m 250.1–1a, la russille. n 250.2–2a, la russille s mc 312a, rocher des hirondelles praedictyorbitolina claveli schroeder d 136.0-3b, pic de l’oeillette e 136.1-3a, pic de l’oeillette f 136.0-2a, pic de l’oeillette j 6549a2, mont de musièges k 6549a3, mont de musièges l 6548b, mont de musièges o 7041-3, la russille p 7040-12a, la russille q 7040-15a, la russille r 7040-14a, la russille geologia croaticamarc a. conrad and bernard clavel: a lithocodium and bacinella signature of a late hauterivian, local microbial event... 243 geologia croatica geologia croatica 61/2–3 244 parasequence 3, only 0.8 m-thick, is visible in a small quarry, next to the d187 road (at greenwich coord. 46.02616° n, 5.96355° e). it has a sharp boundary with the previous interval and consists of a knobbly limestone, free of detrital quartz, containing numerous lithocodium crusts (figs. 5, 6), acting as binders in a micropeloidal matrix of automicrite (see below). transgressive deposits are absent. the accompanying biota includes subordinate amounts of bacinella, a heterotrophic biota including bryozoans and sponges, small textularids, rare dasycladalean algae and key orbitolinids (see below). quite large, idiomorphic dolomite crystals are also present. the lithocodium and bacinella layer is dated by orbitolinids at mont de musièges. as at pic de l’oeillette, an assemblage containing praedictyorbitolina busnardoi and p. claveli, is overlain by the fi rst specimens of p. carthusiana. only part of the next, parasequence 4 is shown in figs. 3 and 4. the succession starts with 3.5 m-thick, angular and very coarse grained transgressive deposits, which are probably related to the adjacent vuache fault system. rudists occur in the highstand tract, with open sea infl uences decreasing progressively upsection. 2.3. platform margin – val de fier section location (fig. 4) is 4 km south of seyssel (haute-savoie), on the d14 road, at the entrance of a tunnel (lambert coord. 872.76/109.40). parasequence 2 is missing. the 3 m-thick parasequence 3 occurs above a fl ooding surface, in sharp contrast with the underlying, reefal oolitic grainstones belonging fi gu re 4: local, detailed correlations in the lower part of the “urgonien s.str.” limestone. considering the general palaeogeographical setting, approximately running in a sw–ne direction, the most external location is mont de musièges. hence, it is placed on the left hand side in the profi le. vuache fault system according to donzeau et al. (1998). rocher des hirondelles section: see detailed log in conrad (1969). other sections: logs are taken from the author’s unpublished thesis manuscript. geologia croaticamarc a. conrad and bernard clavel: a lithocodium and bacinella signature of a late hauterivian, local microbial event... 245 to parasequence 1. it consists of single or multiple lithocodium and bacinella crusts, binding a wackestone containing numerous bryozoans, echinoids, pelecypods and some transported ooliths. a basal transgressive layer is absent and there is no idiomorphic dolomite. paraquence 4 is observed next, on top of a conspicuous joint, marking the fl ooding surface. only part of it is shown in fig.4. the transgressive tract consists of deeper water, peloidal packstone, typically containing lenticulina sp. and common choffatella decipiens. based on the literature, e.g. immenhauser et al. (2004), the latter foraminifera indicates open marine environments, below fair-weather wave base, but within the reach of storm waves. biotic restriction occurs much higher up in the urgonian limestone. 2.4. platform margin – perte de la valserine section location (fig. 4) is 1.7 km nnw of bellegarde-sur-valserine (ain), at (lambert coord. 868.87/131.50). parasequence 1 is observed on the valserine river bed and therefore remains inaccessible. the lack of parasequence 2 can therefore only be inferred from nearby locations. the 6 m-thick parasequence 3 consists of very numerous, angular fragments of lithocodium crusts (fig. 7), which are embedded in fl oatstones also containing encrusting bryozoans, numerous oyster and echinoid debris, including spines, microgastropods, and diverse foraminifera, coptocampylodon lineolatus (incertae sedis), and common specimens of pseudoactinoporella fragilis, a dasycladalean alga. idiomorphous dolomite is present (fig. 7) and a few, probably reworked ooliths are scattered in the sediment. fi gu re 5: lc: lithocodium aggregatum crust, sediment-binding. fam: fl uorescent pelletal automicrite. f: fl oatstone containing numerous lithoclasts of automicrite. upper hauterivian, mont de musièges (hautesavoie), sample conrad 84, normal transmitted light. fi gu re 6: a: lithocodium aggregatum crust, binding a pelletal automicrite; lithoclasts of pene-contemporaneously reworked automicrite; normal transmitted light. b: epifl uorescence image of the same view. the automicrite fl uoresces considerably, indicating the presence of primary organic matter. in contrast, the secondary, blocky calcite cement fi lling cavities in the lithocodium crusts remains dark. also the lithocodium crust is fl uorescent, supporting a calcimicrobial origin. upper hauterivian, mont de musièges (haute-savoie), sample conrad 84. fi gu re 7: lithocodium aggregatum fl oatstone. f: dolomitized matrix containing numerous fragments of lithocodium. l: large fragment of lithocodium crust. d: large dolomite crystal. upper hauterivian, perte de la valserine (ain), sample conrad 631, normal transmitted light. geologia croatica geologia croatica 61/2–3 246 a single, inconspicuous level of lithocodium and bacinella bindstone is present in the mid part of the interval. the pieces of lithocodium are interpreted as having originated from bindstone deposits forming hard substrates, which were fragmented and re-deposited in an allomicrite. in contrast to the mont de musièges and val de fier sections, normal marine biota such as bryozoan micro-encrusters and sponges are absent from the next, parasequence 4 deposits. the transgressive tract begins abruptly with a 3 m-thick, low energy and burrowed wackestone, containing angular rudist debris, foraminifera and ostracods. rudist biostromes (urgonian facies s. str.) are located up-section, in the highstand tract. 2.5. platform margin – boge sur confort section location (fig. 4) is 5 km north of bellegarde-sur-valserine, on the d16 road (lambert coord. 870.3/134.5). here also, parasequence 2 is missing. the 11 m-thick parasequence 3 rests directly on an oolitic grainstone belonging to the top of parasequence 1. as at perte de la valserine, it contains numerous, angular pieces of lithocodium, with bacinella, bryozoans, scat tered corals debris, foraminifera including rare orbitolinids, and some dasycladalean algae. the transgressive tract displays a rather inconspicuous upward shoaling trend, fi rst with a basal fl oatstone including lenticulina sp., grading to grainstones containing an increasing number of dasycladalean algae such as pseudoactinoporella fragilis. both bindstone layers was dolomite are apparently missing. as at perte de la valserine, an open sea biota is absent from the overlying parasequence 4. the basal, slightly deeper water transgressive tract consists of a wackestone containing some transported ooliths. rudist biostromes occur up-section, in the highstand tract. 2.6. platform margin – rocher des hirondelles section location (figs. 1, 3) is 15 km north of bellegarde-sur-valserine, on the d991 road (lambert coord. 874.0/144.7). a detailed account of the section was fi rst published by conrad (1969). for later developments, reference is made to clavel et al. (2007). at the time of writing, the original thin section material was unfortunately missing, and therefore the following brief account is based on the literature. the level of interest (parasequence 3) is 4–5 m-thick, occurring on top of an oolitic packstone belonging to parasequence 1. evidence of deeper water, transgressive deposits is missing. lithocodium crusts suddenly appear in a basal grainstone also including some reworked ooliths. a lithocodium bindstone occurs higher up, but without dolomite. bryozoans, microgastropods and dasycladalean algae are present throughout the interval. at rocher des hirondelles, the lithocodium and bacinella layer is dated by orbitolinids. here also, a rich assemblage including praedictyorbitolina busnardoi and p. claveli is followed, up-section, by the fi rst specimens of p. carthusiana. only part of the overlying parasequence 4 is shown in figs. 3 and 4. the succession begins abruptly with an exceptionally thick (52 m), transgressive sequence of grainand lime rudstones, containing unaltered, angular debris represetnaing an open marine, shallow water biota. presumably, these are scarp deposits related to the past presence of an active fault belonging to vuache system. up-section, in the angulicostata ammonite zone (uppermost hauterivian), they are followed by highstand deposits containing rudists. 2.7. platform margin – la russille and other nw switzerland sections location (fig. 1) is 7 km east of vallorbe (canton vaud), on the road between montcherand and lignerolle, at latitude 46.73° n, 6.48° e. the section (fig. 3) is of historical interest. for a review, see for example conrad & masse (1989), blanc-aletru (1995) and clavel et al. (2007). also at la russille, a rich assemblage of orbitolinids including prae dictyorbitolina busnardoi and p. claveli straddles the “urgonien jaune”, the improperly called “marne de la russille” (a narrow argillaceous interval of regional extent) and the “urgonien blanc”. the fi rst specimens of p. carthusiana occur 3 m above the base of the “urgonien blanc”. the lithocodium and bacinella deposits are missing at la russille and elsewhere in the swiss cantons of vaud and neuchâtel. a study comprising a number of mineralogical analyses was carried out by blanc-aletru (1995) in this area, in an effort to understand the signifi cance of several unconformities observed in the “urgonien jaune”, the “marne de la russille” and the “urgonien blanc”. at la russille and vallorbe, the “urgonien jaune” consists of a bioclastic, partly oolitic shallow water limestone capped by coral biostromes. after blanc-aletru (1995, fi g. 84, 141), at vallorbe, dolomite unexpectedly occurs at the top of the “urgonien jaune”, while carbonate dissolution is present, and kaolinite is the leading clay mineral, in the overlying, transgressive “marne de la russille”. here, these signals of terrestrial exposure are tentatively correlated with parasequence 3, elsewhere forming the lithocodium and bacinella layer. 3. paleontological age determination and correlation in the southern jura, at mont de musièges and rocher des hirondelles, the lithocodium and bacinella layer is dated by an assemblage of three species of orbitolinids, combining part of the praedictyorbitolina busnardoi and p. claveli concurrent range zone, a few metres below the appearance of p. carthusiana. p. busnardoi (pl. i) is upper hauterivian pro parte, (sayni to near the topof the ligatus ammonite zones); p. claveli (pl. i) is upper hauterivian to lower barremian pro parte, (sayni to nicklesi pro parte); p. carthusiana (clavel et al., 2007, pl. 3) is upper hauterivian pro parte to lower barremian pro parte, (top of the ligatus to the base of the caillaudianus). at pic de l’oeillette, in the pre-subalpine domain, this assemblage occurs in talus deposits, directly dated by a specimen of plesiospitidiscus gr. ligatus, an index ammonite (pl. i). in the swiss canton of vaud jura, the same assemblage of orbitolinids straddles a narrow argillaceous interval (improperly called the “marne de la russille”), separating the “ur gonien jaune” from the “urgonien blanc”. in the same general area, at la sarraz – les buis, the upper part of the “urgeologia croaticamarc a. conrad and bernard clavel: a lithocodium and bacinella signature of a late hauterivian, local microbial event... 247 gonien jaune” is dated upper hauterivian by signifi cant assemblages of dinocysts and calcareous nannofossils (clavel et al., 2007). as for the dasycladalean algae, at val de fier, the layer with lithocodium and bacinella contains the typically hauterivian dissocladella hauteriviana. at mont de musièges, a sample taken 3 m above the bindstone layer contains suppiluliumaella corbarica. the species is upper hauterivian pro parte, (sayni and ligatus ammonite zones), (clavel et al., 2007). based on these observations, the level with lithocodium and bacinella must be assigned to the ligatus zone which represents the mid part of the upper hauterivian. the layer with lithocodium and bacinella is in between the valanginian weissert oae and the latest hauterivian (upper part of the angulicostata auct. zone), faraoni oae (for reference see for example baudin & al., 2006). hence, it seems unrelated to a large-scale, signifi cant oceanographic event, and/or global climate change. it is more indicative of being a consequence of locally abnormal conditions, such as those resulting from a sudden infl ux of key nutrients, perhaps of nearby terrestrial origin. 4. sequence stratigraphy defi nitions introduced by schlager (2004, 2005) are used here. based on bioand lithofacies analyses, at least four units are present in the study interval (figs. 3, 4). they are bounded by fl ooding surfaces, with no evidence of exposure, correspond ing to type-3 sequence boundaries. still, these depositional parasequences, as described below, are succinctly compared to the subdivisions elaborated by clavel et al. (1995), using the exxon terminology. parasequence 1 presents the onset of the urgonian deposits. it is up to 18 m-thick, on top of a clear-cut fl ooding surface, followed by a conspicuous, quartz -bearing transgressive tract. the highstand tract, almost entirely oolitic, is capped by coral biostromes at val de fier. using the terminology introduced by clavel et al. (1995), parasequence 1 corresponds to the ha5 sequence lowstand tract, covering, for example the upper part of the “urgonien jaune” at la russille, in the vaud jura canton. the 7 m-thick parasequence 2 was logged only at mont de musièges, in the southeastern-most part of the area, in the direction of the subalpine depocenter. the depositional environment is markedly deeper than in the previous interval, with oolites appearing only near the top of the highstand tract. as shown by fig. 3, the base fl ooding surface of parasequence 2 is tentatively correlated with an argillaceous, hemipelagic interval at pic de l’oeillette, in the pre-subalpine domain. at mont de musièges, the parasequence 2 corresponds to the ha5 transgressive tract, and the ha5 highstand tract pro parte. the bindstone and/or fl oatstone layer with lithocodium and bacinella matches parasequence 3, abruptly interrupting parasequence 2 at mont de musièges and, elsewhere, parasequence 1. the thickness varies considerably, reaching an 11 m maximum measured at boge sur confort, in the area of the vuache fault system. the base of parasequence 3, taken as a datum, is considered as corresponding to a local, “instantaneous” m (microbial) carbonate factory event. it is tentatively correlated with the transgressive base of the improperly called “marne de la russille”, in the vaud jura canton. alternatively, the top of the layer with bacinella and lithocodium may be locally diachronous and since masked by the rapid deposition of bioclastic debris. at rocher des hirondelles, parasequence 3 corresponds to part of the ha5 highstand tract. finally, parasequence 4 corresponds to the onset of the urgonian t (tropical) and photozoan carbonate factory, an important event of regional extent, traceable as far as the presubalpine domain (fig. 3) and beyond, at the base of the urgonian cliff. at val de fier, a 12 m-thick, deeper water trans gressive tract occurs on top of a conspicuous fl ooding surface. at mont de musièges and rocher des hirondelles, the transgressive succession consists of thick, angular, often coarse grained deposits the presence of which is interpreted as being linked to submarine escarpments of tectonic origin. in same area, corresponding to the vuache fault system, more or less coeval deposits witness the impressive effect of such syn-sedimentary activity with, for example, highly heterogeneous channel-fi lls at bellegarde-sur-valserine. at la russille (canton vaud jura), the parasequence 4 transgressive tract corresponds to the ha6 lowstand tract. 5. interpretation of the layer with lithocodium and bacinella the layer was initially interpreted by conrad (1969) as a marine facies corresponding to the back fl ank of oolite shoals. in a draft version of the present article, the coarse, rhombohedral dolomite accompanying the lithocodium crusts was considered as supporting the dorag depositional model. this model (badiozamani, 1973) calls for dolomite precipitation in the marine and fresh water mixing zones, for example in the vicinity of islands subject to heavy rains. actually, although possible, the dorag model is rather unlikely. it is highly controversial (for a review, see moore, 2001) and still requires well-documented examples for support. 5.1. epifl uorescence tests in the layer with lithocodium and bacinella, the binding-trapping mechanism is primarily performed by lithocodium crusts, bacinella, and other micro-encrusters denoting an open marine habitat, and by fi ne-grained, organo-mineralic deposits conceivably generated by microbes. six epifl uorescence tests were carried out in thin section, to check for the presence, at mont de musièges, of automicrite containing residual organic matter. the tests were carried out by b. van der kooij, at the department of sedimentology and marine geology vrije universiteit, amsterdam. a zeiss epifl uorescence microscope was used mounted with an hg vapour light and a bypass fi lters for the green wavelength. both the automicrite matrix and the lithocodium crusts are brightly luminescent (fig. 6), indicating a high organic content. in contrast, the secondary, granular mosaic calcites fi lling up the pore spaces, are non luminescent, and hence devoid of organic material. 5.2. the microbial mediation, anoxic conditions model a possible interpretation of the lithocodium and bacinella deposit is the sudden development, next to an otherwise norgeologia croatica geologia croatica 61/2–3 248 mal, open marine environment, of anoxic conditions, leading to the formation of microbial mats and bacterially-driven, epigenetic dolomite. in such an unbalanced environment, lithocodium and bacinella were possibly acting as low-trophic, opportunistic calcifi ers, at work in semi-enclosed pools. a possible modern analogue is the lagoa vermelha, a moderately hypersaline, high ph and anoxic lagoon located 90 km east of rio de janeiro, where dolomite precipitation occurs. experiments carried out by warthmann et al. (2000), on a particular strain of sulphate-reducing bacteria found in the lagoa vermelha, indicate that bacterial sulphate reduction can induce the precipitation of signifi cant amounts of metastable, nonstoichiometric dolomite which, in the fossil record, may evolve as the central nucleus of larger, rhombohedral dolomite crystals. a disadvantage of the lagoa vermelha model is that apart from the automicrite, clearly of microbial origin, the layer with lithocodium and bacinella contains no indices of mesoor eutrophic conditions, such as an impoverished biota with triloculina sp., or euhaline assemblages with charophytes, brackish molluscs and ostracods. in contrast, the lithocodium crusts are accompanied by numerous, freshly broken and unaltered fragments of a typically stenohaline biota. 5.3. the microbial mediation, oxic conditions model another possible model is based on highborne cay, in the bahamas, where stromatolite build-ups and micritic crusts are presently forming and trapping oolites in open marine environments of normal salinity. the location is at the back of a fringing algal reef (reid et al., 2000 and references therein). cyanobacteria are the primary producers in this eco-system. according to baumgartner et al. (2006), sulfate-reducing bacteria (srb), although traditionally viewed as restricted to anoxic zones, can tolerate oxygen. certain srb strains not only survive in the oxic zone of microbial mats, but even exhibit some of their highest rates of sulfate reduction during oxic conditions. although it is yet to be confi rmed, dolomite precipitation does not seem to occur at highborne cay, whilst epigenetic dolomite is locally found in the layer with lithocodium and bacinella. the origin of organogenic dolomites has been the object of a number of studies. among several processes, anaerobic methane oxidation favours dolomite formation. in the study area, fi ne mud, and syngenetic dolostones are missing in the urgonian limestone. however, besides the layer with lithocodium and bacinella, coarse rhombohedral, epigenetic dolomite, although rare, is also found higher up in the formation. such an occurrence was described by conrad (1969, p. 24 and fi g. 7), from a barremian limestone with rudists, in the subalpine domain. pervasive dolomitization occurs near the top of a small sequence, right below beach deposits overlain by mm-thick coal seams. lithocodium and bacinella are missing in this case. 5.4. distribution of lithocodium and bacinella large lithocodium-bacinella build-ups, such as those interbedded with rudist banks in the aptian of the middle east, are lacking in south-east france. these organisms occur in the “urgonien blanc” (or “urgonien s. s.”) in the following manner: (1) in the partly dolomitized layer dealt with in this article, lithocodium crusts are found either alone or accompanied by other micro-encrusters including bacinella; (2) bacinella oncoids, up to several cm-large, are coated by lithocodium; they commonly occur in non-dolomitic fl oatstones which are associated with, but separate from rudist boundstones, in platform interior deposits; similar oncoids were studied by védrine et al. (2000) in the oxfordian of the swiss jura. accord ing to these authors, the bacinella-lithocodium association characterizes lagoonal environments with oligotrophic conditions, in normal-marine waters; (3) bacinella alone (lithocodium missing) commonly occupies primary cavities in rudist biostromes; (4) in the subalpine domain, dolomitized lithoclasts formed by questionable lithocodium debris, occasionally form a minor component of thick grainstones, forming sand waves on the margin of the platform. if related to the type (1) above, these lithoclasts may indicate small scale exposures of the platform, between the shoreline and the shelf break, followed by the erosion and re-sedimentation of temporary, in situ bindstone deposits. with reference to the above, observations made by other authors confi rm that lithocodium aggregatum and bacinella irregularis are taxonomically distinct organisms. as for lithocodium, its origin remained controversial for decades. recently cherchi & schroeder (2006) have shown that it cannot be a loftusiacean foraminifera. instead it is considered as representing a colony of calcifi ed cyanobacteria. this interpretation is supported by our observation showing that the dark lithocodium crusts have a high organic content. 6. conclusions the layer with lithocodium aggregatum and bacinella irregularis is found in the southern jura, in the lower part of the “urgonien s.s.” formation. two variants occur: (1) bindstones containing fl uorescent automicrite and epigenetic dolomite; (2) much thicker fl oatstones containing, inter alia, numerous fragments of lithocodium crusts. by analogy with the modern lagoa vermelha, in brazil, one interpretation calls for a sudden, local anoxic episode of microbial carbonate and dolomite precipitation, interrupting the normal marine carbonate factory. another model calls for an analogy with the highborne cay area, in the bahamas, where stromatolite build-ups and micritic crusts are presently forming, in an open marine environment of normal salinity. lithoand biofacies analyses show that the depositional setting, during the earliest development of the “urgonien s. s.” carbonate platform, consists of a stack of four, upward shoaling depositional parasequences, bounded by fl ooding surfaces. parasequence 1 represents the initial onset of the “urgonien s. s.”. parasequence 2 occurs in the south-eastern-most part of the area, in the direction of the subalpine depocenter. parasequence 3 matches the layer with lithocodium and bacinella, abruptly interrupting parasequence 2 or parasequence 1, depending on location. wide thickness variations (0.8–11 m) are interpreted as resulting from simultaneous tectonic activity, in the area of the currently still active vuache fault sysgeologia croaticamarc a. conrad and bernard clavel: a lithocodium and bacinella signature of a late hauterivian, local microbial event... 249 tem. parasequence 4, fi nally, corresponds to the resumption of the normal, urgonian carbonate factory. the lithocodium and bacinella event is of upper hauterivian age, in the ligatus ammonite zone. dating elements are provided, directly, by an assemblage of three species of orbitolinids and, indirectly, by an index ammonite found in the pre-subalpine domain. based on these elements, the lithocodium and bacinella event is correlated with platform talus deposits, in the pre subalpine domain, and with the improperly called “marne de la russille”, in the swiss jura. it is signifi cantly older than the latest hauterivian faraoni anoxic event (oae) and unlikely to be linked with global climate change. acknowledgement the authors wish to thank wolfgang schlager (vrije university, amsterdam) and geraint w. hughes (saudi aramco, dhahran) for their most helpful and constructive reviews. thanks to the intermediation of elias samankassou (university of geneva), bram van der kooij (vrije university) who kindly assisted in carrying out several, successful epifl uorescence tests. references arnaud-vannea, a. (1980): micropaléontologie, paléoécologie et sédimentologie d’une plate-forme carbonatée de la marge passive de la téthys: l’urgonien du vercors septentrional et de la chartreuse (alpes occidentales). – géologie alpine, mémoire h.s. 11, 1–874. badiozamani, k. (1973): the dorag dolomitization model – application to the middle ordovician of wisconsin. – j. sediment. petrol., 43, 965–984. banner, f.t., finch, e.m. & simmons, m.d. (1990): on lithocodium elliott (calcareous algae); its paleobiological and stratigraphical signifi cance. – j. micropalaeontol., 9, 21–36. baudin f., busnardo, r., beltran, c., de rafélis m., renard, m., charollais, j & clavel, b. (2006): enregistrement de l’évènement anoxique faraoni (hauterivien supérieur) dans le domaine ultrahelvétique. – rev. paléobiol., 25, 525–535. baumgartner, k.l., reid, r.p., dupraz, c., decho, a.w., buckley, d.h., spear, j.r., przekop, k.m. & visscher, p.t. (2006): sulfate reducing bacteria in microbial mats: changing paradigms, new discoveries. – sediment. geol., 185, 131–145. blanc-alétru, m.c. (1995): importance des discontinuités dans l’enregistrement sédimentaire de l’urgonien jurassien. micropaléontologie, sédimentologie, minéralogie et stratigraphie séquentielle. – géologie alpine, mémoire hs, 24, 1–299. blondel, t. (1990): lithostratigraphie synthétique du jurassique et du crétacé inférieur de la partie septentrionale de la montagne du vuache (jura méridional, haute-savoie, france). – arch.sci., 43/1,175–191. charollais, j., clavel, b., amato, e., escher, a., busnardo, r., steinhauser, n., macsotay, o & donze, p. (1983): etude préliminaire de la faille du vuache (jura méridional). – bulletin de la société vaudoise des sciences naturelles, 76, 217–256. charollais, j., clavel, b. & maurice, b. (1989): l’hauterivien du jura du bassin genevois. – mémoires de la société neuchâteloise des sciences naturelles, 11, 49–72. charollais, j., clavel, b., schroeder, r., busnardo, r., cherchi, a., massera, m., muller, a., orsat, v. & zaninetti, l. (2001): installation et évolution de la plate-forme urgonienne du jura aux chaînes subalpines septentrionales (bornes, baug es, chartreuse, suisse, france). – arch. sci., 54, 139–169. cherchi, a. & schroeder, r. (2006): remarks on the systematic position of lithocodium elliott, a problematic microorganism from the mesozoic carbonate platforms of the tethyan realm. – facies, 52, 435–440. clavel, b., charollais, j., conrad, m.a., jan du chêne, r., busnardo, r., gardin, s., erba, e., schroeder, r., cherchi, a., decrouez, d., granier, b., sauvagnat, j. & weidmann, m. (2007): dating and progradation of the urgonian limestone from the swiss jura to south east france. – z. deut. geol. gesellsch., 158/4, 1025–1062. clavel, b., charollais, j., schroeder, r. & busnardo, r. (1995): réfl exions sur la biostratigraphie du crétacé inférieur et sur sa complémentarité avec l’analyse séquentielle: exemple de l’ur gonien jurassien et subalpin. – b. soc. géol. france, 166, 663–680. conrad, m.a. (1969): les calcaires urgoniens dans la région entourant genève. – eclogae geol. helv., 62, 1–79. conrad, m.a. & masse, j.-p. (1989): corrélations des séries carbonatées de l’hauterivien et du barrémien pro parte dans le nordouest vaudois (suisse). – mémoires de la société neuchâteloise des sciences naturelles, 11, 307–322. donzeau, m., wernli, r. & charollais, j. (1998): interprétation nouvelle de la géométrie de l’accident du vuache dans le jura méridional: le relais de failles transpressif sénestre léaz-champromier (ain). – géologie de la france, 2, 25–45. elliott, g.f. (1963): problematical microfossils from the cretaceous and palaeocene of the middle east. – palaeontology, 6, 293–300. hillgaertner, h., van buchem, f.s.p., gaumet, f., razin, p., pittet, b., grötsch, j. & droste, h. (2003): the barremian–aptian evolution of the eastern arabian carbonate platform margin (northern oman). – j. sediment. res., 75, 756–773. immenhauser, a., hillgaertner, h., sattler, u., bertotti, g., schoepfer, p., homewood, p., varhrenkamp, p., streuber, t., masse, j. p., droste, h., van koppen, j., van der kooij, b., van bentum, e., verwer, k., hoogerduijn-strating, e., swinkels, w., peters, j., immenhauser-potthast, i. & al maskery, s.a. (2004): the barremian–lower aptian qishn formation (huqf area, oman): a new outcrop analogue for kharaib/shu’aiba reservoirs. – geoarabia, 91, 153–194. immenhauser, a., hillgaertner, h. & bentum, e.v. (2005): microbial-foraminiferal episodes in the early aptian of the southern tethyan margin: ecological signifi cance and possible relation to oceanic anoxic event 1a. – sedimentology, 52, 77–99. koch, r., moussavian, e., ogorolec, b., skaberne, d. & bucur, i.i. (2002): development of a lithocodium (syn. bacinella irregularis) – reef-mound – a patch reef within middle aptian lagoonal limestone sequence near nova gorica (sabotin mountain, w – slovenia). – geologija, 45, 71–90. moore, c.h. (2001): carbonate reservoirs. – elsevier, amsterdam, 444 p. pascal, a. (1979): utilisation des éléments traces dans la caractérisation des paléomilieux sédimentaires urgoniens basco-cantabriques (espagne). – géobios, mém. spéc. 3, 331–345. reid, r.p., visscher, p.t., decho, a.w., stolz, john f., bebout, b.m., dupraz, c., macintyre, i.g., paerl, h.w., pinckney, j.l., prufert-bebout, l., steppe, t.f. & desmarais, d.j. (2000): the role of microbes in accretion, lamination and early lithifi cation of modern marine stromatolites. – nature, 406, 989–992. schlager, w. (2004): fractal nature of stratigraphic sequences. – geology, 32, 185–188. geologia croatica geologia croatica 61/2–3 250 schlager, w. (2005): carbonate sedimentology and sequence stratigraphy. – concepts in sedimentology and paleontology, 8, sepm, tulsa, 200 p. védrine, s., strasser, a. & hug, w. (2000): oncoid growth and distribution controlled by sea-level fl uctuations and climate (late oxfordian, swiss jura mountains). – facies, 53/4, 535–552. warthmann, r., van lith, y., vasconcelos, c., mckenzie, j.a. & karpoff, a.m. (2000): bacterially induced dolomite precipitation in anoxic culture experiments. – geology, 28/12, 1091– 1094. manuscript received january 8, 2008 revised manuscript accepted june 16, 2008 geol. croat. 1 49/2 1129 ~ 1341 3 figs. 1 1 tab. zagreb 1996 lranognathus sosioensis n.sp., a new conodont species from the changxingian (late permian) of western sicily h einz kozur' and he lfri ed mostler' key words: conodonts, iranognathus sasioensis n.sp. , changxingian, weste rn sicily. abstract ironogllat!jus sosiocllsis n.sp., a changxingian (latest permian) conodonl species of western sici ly, is the youngest iranognoljws species occurring immediately below the permian -triassic bou ndary. the middle permian and part of lhe laic permian pelagic conodo nt faunas of western sicily afc cold bahom-w,ller faunas, vcry di f ferent form the contemporaneoll s pelagic warm water faunas . the facial pre­ tensions of i. m.i'iocl/sis arc nol yet known. schliisselworte: conodonten, iralloglwthlfs sosioensis n.sp., changxingian, west-sizilien. zusammcnfassung !u/llognothils sosioel1sis i1. sp. , ei ne conodonlenan aus dem changxingian (o\)ersles perm) von westsizilien, wird beschrieben. es handelt sich lim di e stratigraphiseh jungste frolwgllatfllls -art, die lll1miltclbar unlcrhalb dcr pcrm{l'rias-grcnzc vorkomml. di c 111i t­ tclpcrrnischen lind ein tei l der obcrpermischcn pclagischcn conodon­ lcnfaull cil voil wcslsizil icil waren bewohncr dcs kal ten dodcn ­ wasscrs. sic si nd sehr verschieden von den gleichaltrigen pelagischen warmwasscrfaunen . d ic faziesanspriiche von f. sosioensis konnten !loch nichl gekl;lrt wcrden. 1. introduction pelagic permian rocks of western sicily contain very rich co nodo nt faunas. the ri chest samples are cathedra l ian and changxingian calcarenites that partly contain more than 1000 conodonts per kg sample. most o f the occurring conodont species were described or figu red by bender & stoppel (1965), kozur (1975, 1990a, b. 1992b, 1993a). catalano et al. (1988, 1989, 1991 . 1992) and gullo & kozur (1992,1993). the age determinations of the permian deep-water sequence of western sicily are based mostly on th ese conodont s (catalano et al., 1988, 1991, i rezsli u. 83, hi029 budapest, hungary. 2 ins litul fur gcologic lind paliion lologic, universit1it innsbruck, innrain 72, a-g020 inn sbruck, au stria. iu s unes 0 359 1992; kozur, 1989a, b, 1992a, b, e, 1993a. b, 1994. 1995; gullo & kozur. 1992, 1993). lranognathus sosioejlsis n.sp. belongs to the rare conodont elements. only one specimen of this spccics is found among 100~ iooo specimens of other changxin~ gian conodont spec ies and most of the conodont-rich samples d id not yield any l. sosiocjlsis. 2. geological setting and age of the investigated fauna the hololype of lranognathus sosiocnsis was found in the claystone unit of the tonente san calogero sec­ tion, ssw of the pietra di salomone block in the sosio valley (western sici ly). near palazzo adriano (fig. i). locality and section data are given in catalano et al. (1991). the stratig raphic success ion is shown in table i. the predominantly red-coloured claystone un it is mostly of changxingian age. dzhulfian conodonts were found only in the lowermost part with predominating li ght-gray claystones, but thi s part is presently no t exposed. the claystone un it contains some thin (0.6-2 cm) intercalation s of calcarenites that represent distal turbidites . only one. partly silicified bed is th icker (-20 cm), from which thc holotype of iranognathus sosiocl1 sis n.sp, was derived. th is bed also contains rich conodont and si liceous sponge spicule associations. the sponge spicules coil­ sist of forms that lived dominant ly on thc upper sl ope in water less than a few hundred metres deep. in contrast, all species res tricted to shallow-pelag ic warm water conodont faunas (c. subcarinata group) , arc absenl. 130 b • 2( o 60 km ~ n t palazzo adriano fig. i location of the investigated outcrops in wes lern sicily, italy. legend: black} predominan tly wordian sosio limestone klippes (slope facies with fllsulinid -bearing shallow-water limestone blocks); a) rupe di san calogero and pielra dei saracini, three adjacent isolated limestone blocks, no longer accessible; b) rupe del passo di burgio; pietra di salomone. stars) permian base of slope facie s and triassic cover ; i) several outcrops c. 350 m south of pietra dci saracini covering the roadian (basal middle permian, guadalupian series) to julian (m iddle carnian) interval; 2) outcrops c. 100 m ssw of rupe del passo di burgio. mainly lower cathedral ian (cis -ural ian, early permian) turbidites well exposed west of a small road, along the road lower cathedralian turbidites (part ly exposed) and tectonically adjacent changxin­ g ian rcd marls and thick calcarenites, no longer exposed, but small floated blocks of calcareni tes still present. crosses) tor­ rente san calogero section, perm ian deep basin facies and parts of the tri assic cover. clarkilla cilangxingensis (wang & wang) and c. sosioejlsis gullo & kozur dominate this fauna, but c. def/ecla (wang & wang) and c. cf. carillala (clark) are subordinate elements. h. latidentallis (kozur, mostler & rahimi-y azd), h. iypicalis (sweet), sweelocr;slallis ga/eallls (bender & stoppel) and the new franognathus sosioensis arc very rare. clarkino sosioensis occurs in basinal sections of northwestern iran and azerbaidzhan in the uppermost 10 em of the changxingian. it is also rare at the same level in the strato type of the changxi ngian stage in south china (meishan). c. changxillgensis and c. de/lecla are dominating late changxingian species, but their known ranges begin earlier, at least in the early changxingian . hilldeodlls fatidelltatus is a characteris­ tic conodont of the uppermost changxingian both in pelagic sed iments (s outh china, azerbaidzhan, northgeologia croatiea 49/2 western and central iran) and from shallow-water deposits (tesero oolite of the southern alps) , but is more common in the latter fac ies. the age of the fauna is therefore lates t changxingian. despite the fact that the characteristic shallow pelagic warm water conodont c. su/jearinala and near related forms are missing, the sponge spicules indicate a strong input of faunal elements from the warm water upper shelf. therefore, the absence of c. subearinata may also be strat igraphicall y controlled , because this species is missing in the uppermost centimetres of the changxingian in south china, transcaucasia and cen­ tral iran. for thi s reason, it is not obvious, whether r. sosioensis is a representative of the cold bottom-water fauna or of the warm water shallow pelagic fauna. i . sosioensis is absent both in typical cold bottom -w ater faunas of the red changxingian deep sea clays, and in the late changxingian slope facies (calcarenites without in tercalations of red deep-water clays) with exclusively shal low pelagic warm water conodo nt faunas and fusulinids. on the other hand, most specimens were round in a facies, transitional between these two coi1 sisting of red deep-water clays wi th several thick cal­ careni te intercalations formerly exposed along a small road about 100 m south of the rupe del passo di burgio block (fig. j). seemingly ironognathlls sosioellsis lived on the slope and is absent both in the basin and in the uppermost part of the slope and on the shel f. 3. description of irwlognathus sos;oells;s genus: iranognalhus kozur, mostler & rahlmi-y azd, 1975 type species: iranognathlls unicoslatlfs kozur, mostler &rahimi-yazd, 1975 iranogllat/llls sosioensis n.sp. (figs. 2, 3) derivation of name: according its occurrence in the sesie valley area. holotype: the specimen on fig. 2; rep. -no. komo 13-2-95/11-50. type locality: torrente san calogero section ssw of pietra di salomone (near palazzo adriano), western sicily (italy), see fig. i and table i. type stratum: the only thick (about 20 em) cal­ carenite within red clays or the claystone unit. latest changxingian. material: 4, partly broken specimens from the only thick (late changxjngian) calcaren ite bank within the claystone unit of the torrentc san calogero section, 12 broken specimens from late changxingian thick cal­ carenites south of the rupe del pas so di burgio block. diagnosis: an iranognathus species with numerous smal l pustulose nodes on the platform. nodes partly fused 10 narrow, irregular, but generally longiludinal ribs. k02l1r ~ m os11 'r' ir{/llo~tl(fl'w\' \'oj;(! e l1~i~ n sp '1 new conodont spec ics , , c, .. ' 131 series stage lithology fossils red, mainly in the lower part also light-g ray, deep-water claystones, with upper permian changxingian a few thin intercalations of calcarenites. claystones with albaillellid radiolarians, deep-water sponge spicules, palaeopsychrospheric ostracods = and a few conodonts. calcarenites with common pelagic conodonts, lopingian transported sponge spicules from the slope, palaeopsychrospheric deepwater ostracods and transported ostracods from the slope. dzhulfian p capitanian unknown e wordian gray, ye ll owish weathering claystones . conodonts (m. siciliensis) , r radiolar ians. m i middle permian = olistostrome unit: matrix of gray claystone with reworked sand and garnet a guadalupian grains. olistoliths up to 1 m diameter consisting of turbid itic sandstones, n siltstones (often with flute casts and plant debris) and rare sandy calcarenites. roadian matrix with conodonts (mesogondolelfa phosphoriensis, sweetognathus subsymmetricus) , albaillellid radiolarians and sporomorphs. olistoliths with conodonts (m. idahoensis, m. intermedia) , albaillellid radio larians and sporomorphs. • cathedralian gray and red flyschoid turbidites : graded sandstones , partly fine• early permian (kungurian) conglomerat ic, siltstones, shales and few calcarenites. agglutinating · = foraminifers , conodonts, deep-water trace foss ils. calcarenites also contain • cisuralian fusulinids, ammonites, trilobites, brachiopods, bryozoans, calcareous algae. • artinsk ian • table i basi nal permian suile in lhe sosio valley, western sicily. legend: i presen t in tile torrenle san calogero section ssw of picl ra eli salomone; : present in fofll1 or olisloliths in th e road ian oli stostrome unit. description: platform broadly arrow~like , covered with nulllerous pustulose small nodes that are partly fu sed to narrow , irregular , but generally longitudinal ridges or connected by elevated single rows of pustules . free blade very long, bearing up to 9 denticles decreasing in size posteriorly. carina fused to a pus tll ~ lose ridgc that is in its anterior half often undulate , ind i­ catin g the position of the fused denticlcs. the flaring basal cavity compriscs the ent ire lower surface of the platform. occurrence: single thi ck calcarenite bank in the late changxingian red part of the claystone un it of the toltcntc san calogero section and from changxingian thick calcarenites intercalated with red claystones south of the rupe del passo di burgio block, remarks: the platform sculpture of the wlichi ­ apingian to early changxingian iranognalhlls lara zi kozur , mostler & rahimi-y azd, 1975 and l. lil1icosla llis kozur, mostler & rai-iimi-y azd, 1975 consists of a few high and rather broad longitudi ­ nal ribs (one in 1. unicostallis and two~three in 1. tarazi) . the early permian iranognalhus hllccocllsis (rit~ ter, 1986) displays broad longitudinal ribs that illay disintegrate into several large, hi gh pu stulose nodes. thesc lauer representatives arc similar to 1. sosioel/sis, but their platform is suboval and the nodes arc consid~ erably larger and higher than in i. sosioensis. 4. remarks on the palaeoecology of the middle/late permian conodonts in western sicily the middle permian pelagic conodont faunas of western sicily consist cxclusively of cold bottom~water faunas despite the [act tha t shallow-water faunas from adjacent shelves indicate a tropical climate. the ex is­ tence of cold bottom -water condit ions of an open sea environment at the margin of an ocean is also indicated by ihe presence of palaeopsyeilrospheric oslracod fau ­ nas (kozur, 1989c, 199 i a, b). in ihe cold bollom­ wate r conodont fauna s serrated mesogolldo/ella , the decisive guadalupian guideforms of pelagic warm water faunas, are missing. they are replaced by unser­ rated mcsogoj/dolel/a of the m. p/tosplioriellsis m. siciliellsis group. the exact correlations of these smooth mesogondo/e/la with the middle permian time fig . .l frollogliothlls sosioellsis n.sp ., upper view, torrc nl c san calogero section, from the only thick ca lcarcnitc bcd within red late changxingian cl ays tones, sample tsc 1/94: spec im en wi th somewhat damaged cup, rep.-no . komo 13-2-95/[118, x ioo. geologia croatica 49(2 fig. 2 fr(/li ogll(jth lls sosioellsis il.sp., uppe r view, tor­ re nte san caloge­ ro section, from the only thick ca l­ carenit e bed with ­ in red lal e chang­ xingian claysto­ nes, sampl e tsc 1/94; a) xioo, b) detail of the pustu­ lose nodes, x500. scale is not yet known in detail, but the first appearance of ihe serrated mesogondo{ella, m. serrata (ching), at the base of the guadalupian series nearly coincides with thc first appearance of m. pilosphoriensis youn­ gqist, hawley & mtller and relaled form s. during the changxingian, both pelagic cold boltoi11waler conodont faunas and pelagic warm wate r faunas are present in wcstern sicily. the cold bottom -water faunas characterise the basin and lowc r s lope, the pelagic warm water faunas the upper slope. the changxingian cold bottom-water fauna is characte rized by common c. cf. carinata (clark), c. cliangxingell­ sis (wang & wang) and c. sosioensis gullo & kozur (only in the deep-basin faci es) and a few c. procerocarinata kozur, c. tulaugeusis (t1an) (only in the late changxingian) , c. taylorae (orchard) and hindeodus typicalis (sweet). the pel agic warm water conodont fauna is characterized by c. c/zongxin.­ gensis, c. dejlecta (wang & wang), c. dicerocari­ uata (wang & wang) , c. postwangi (tian), c. subcarinata (sweet), c. wangi (dai & z ha ng) and c. xiangxicl/sis (tlan). some species, like c. c/tang­ xiugensis (w ang & wang) and h. typicalis occur both in cold water and warm water pelagic environ­ ments. the latter speci es is a dominant shallow-watcr conodont, but occurs subordinately also in pelag ic deposits. the changxingian pelagic cold (cool ) water conodont fau na is very similar 10 the conodont fauna of the boreal owceras beds. wuehiapingian cool water fauna s are known from the sail range, kashmir and from eastern greenland. the cady wuchiapingian conodont faunas are charac­ terized by clarkina rosenkrantzi (bender & stopkozlir & mosller: //"mlogllal//iis jujiocnsis n.sp .. a new conodonl species ... pel) and its rclated forms, /-/indeodlfs typica/is and in the peri-gondwana faunas additionally by undescribed species of irall ognathlls and vjafovognalhlls. in the lale wuchiapingian with cycloloblls (e.g. upper zewan for­ mation of kashmir and upper chhidru formation of the salt ran ge) a low diversity conodont fauna is known which is sim ilar to that of the boreal otoceras faunas. this fauna is dominated by c. cf. carinafa and h. typi­ calis. the changxingian warm water conodont fauna of western sicily corresponds lo the typical changxingian co nodont faunas of south china (e.g. from the changxingian st ratotype at meishan), armenian and azerbaidzhanian transcaucasia (with the stratotype of the dorashamian at dorasham) as well as northwestern and central iran. in calcarenites (distal turbidites) pelagic cold and warm water faunas may occur togethcr bccause of thc transport of faunas from the upper slope into the basin. iranogllafhus sosioel/sis n.sp. is on ly known from cal­ carenit es. it co-occurs both with co ld water conodont fau nas (but not in the red deepwater clays without the input of slope material), with mixed cold and warm watcr conodont faunas and with warm water conodont faunas. because calcarenites with cold bottom -water conodon t faunas also contain sponge spicules and ostra­ cods transporlcd from the upper slope, it is not clear, whether i. sosioel/sis lived in the cold bottom-water or whether it is a transported element from the warm water conodont faunas. perhaps this species lived both in cold boltoill-water and in warm surface water, becausc fra ­ nognalhus is known both from the tropical changxin­ gian warm water conodont faunas and from peri-gond­ wana cool-water faunas. acknowledgement the invest igat ion s by h. kozur were sponsored by the deutsche forschungsgemeinschaft whose help is gratcfullyacknowlcdged . 5. references bender, h. & stoppel, d. ( 1965): perm-conodon­ ten.geol. jb. , 82/3 , 331-364, hannover. catalano, r., di stefano, p & kozur, h. (1988): ncw results in the permian and triassic stratigraphy or western sicily with special reference to the section at torrcnte san calogero sw of the piel ra di salomone (sosio valley).atti 74° congr. soc. geol. it. , a, 126-135, benevento. cata lano, r. , di stefano, p. & kozur, h. (1989): lower perm ian albai llellaeea (radiolaria) from sicily and their stratigraphic and paleogeo­ graphic significance. soc. naz. sci. lett. arti napoli, rend. ace. sci . fis. mat., ser. iv , 56 (128), 1-24. 133 catalano , r., di stefano, p. & kozur, h. (1991): permian circumpacifi c deep-water faunas from the western tethys (sicily, italy) ncw evi­ dences for the pos iti on of thc permian tethys.­ palacogeogr., palaeoclimato1., palaeoecol., 87/1-4, 75 -108. catalano, r., di stefano, p. & kozur, 1-1. (1992): ncw data on the permian and triassic stratigraphy of westcrn sicily.n. jb. geo1. palliont. , abh., 184/1 ,25-61. gullo , m. & kozur, h. (1992): conodonts from the pelagic deep-water permian or central western sicily (italy).n. jb. gcol. pauiont., abh., 184/2, 203-234. gullo, m. & kozur, 1-1. (1993): first ev idence of scythian conodonts in s icily.n. jb. geol. palaont. , mh., 1993 (8),477-488. kozur, h. (1975): beitragc zur conodontenfauna des pcrm. geol. pawont. mitt. innsbruek, 5/4, 1-44. kozur, h. (1989a): microfossils (conodonts, radiolar­ ians and ostracods) of the permian " lercara forma­ tion" from western sicily and their bioracial value.10 centenario mem. giuseppe seguenza nal. pal., program, abstracts, field-t rip book, 7, mess ina. kozur, h. (l989b): unter-, mittel und oberpermis­ che pclagische zirkumpazifische tiefwasser[aunen in westsizilien und ihre pajaogcographischc bcdcu­ tung. so. jahrestagung paltiontoiogische gcsell ­ schar!. programm, zusammenfassungen, teil ­ hehmcr, 51, bonn. kozur, 1-1. (l989c): middle/late permian psyehros ­ pheric deep-water ostracods [rom sicily.first european ostracodologists' meeting, abstracts, 13, frankfurt a. m. kozur , h. (l990a): s ignificance of events in con­ odont evolution for the permian and triassic stratig­ raphy.cour. forsch.-inst. senckcnbcrg, 11 7,385408. kozur, [-i. (l990b): the taxonomy of thc gondolellid conodonts in the permian and triassic.cour. forseh. -inst. senckenberg, 1l7, 409-469. kozur, h. (199ia): permian deep-water ostracods from sicily (italy). part i: taxonomy.geol. palliont. mitt. innsbruek, sonderbd., 3, 1-24. kozur, i-i. (1991 b): permian deep-water ostracods from sicily (italy). parl 2: biofacial evaluation and remarks to the si lurian to triassic paleopsychros­ pheric ostracods.geol. palaont. mitt. innsbruck, sonderbd., 3, 25-38. kozu r, h. (i 992a): the pelagic perm ian and triassic deep-water sequencc of western sicily and its con­ tinuation in the eastern mediterranean arc:1.6th congr. oeo!. soc. grecce and 5th field meeting igcp project no. 276, 19-20, athens. 134 kozur, h. (1992b): age and paleoecology or the con­ odont clarkii/o cizallgxillgellsis (wang & w ang).geo!. pabont. mitt. innsbruck, 18, 83-86. kozur, h. (1992c): new stratigraphic, paleoecologic and paleogeographic results in the pcrmian and tri­ assic of the western tethys. 29th intern. geo!. congr., kyoto, japan, abstrac ts, i, 117, kyoto. kozur, t-l. (19930): gul/odus n. gen. a new con ­ odont genus and remarks to the pelagic permian and triassic of' western sicily.jb. gco!. b. -a ., 136/1, 77-87. kozur, h. (1993b): upper permian radiolarians from the sosio valley area, western sicily (italy) and from the uppermost lamar limestone or west tcxas. jb. geo!. b.-a., 136/1,99-123. geologia cromica 49/2 kozur, h. (1994): the early evolution of the southern tethys on the example of western sicily and the interaction of the southern tethys with the alpine­ carpathian belt.in: alcapa ii: geological evo­ lu tion of the alps-carpathian-pannonian system. romanian j. tecl. reg. geo!., 75, supp!. 1, 29-30, bllcure§ti. kozur, h. (1995): pcrmian conodont zonation and its importance for the permian stratigraphic standard scale.geol. paniont. mitl. innsbruck, 20, fest ­ schrift zlim 60. geburtstag von i-ielfried mostlcr, 165-205. manuscript received pebruaiy 12, 1996. revised manuscript accepted september 11 , 1996. geol. croat. 49/2 1227 -230 i 4 figs. i i i zagreb 1996 scienfi/i'c: note seismic line calibration a main reference for the rational exploration and development of very complex oil and gas fields and reservoirs (bizovacki cret case study) proceedings slobodan gacesa' and ivan mesic' key words: seismic line calibration, synthetic seismo­ gram, synthetic attributes, key seismic line. abstract comparison of wejl j log data, and seismic line i reprocess­ ing with synthetic seismogram parameters, rcs ull s in a high level of correlation making possible ihe precise location of the well-ion par­ ticular seismic trace or seismic line 1. results indicate that slich key seismic line (a reference) may be use ful as an entry for three-dimensional (3~) seismic surveys. the application of suc h procedures in complex reservoirs as the 13izovac field area (characterised by fracture porosity) , wi ll minimise 1l1e ri sk in dri lling a horizontal, re-entry well (to determine the pro­ duction potel11ia! of the area around the we !!~!), and drilling a second well on the nonhcasl side of bizovacki cret structure. 1.lntroouctlon the 13izovacki cre! locali ty was discovered during the development of the bizovac oil field after classical interpretat ion of twodimens ional (2d) seismic data. tn the first outpost well, located 2.6 km from the nearest producing well and 1.2 km from a dry well , o il was discovered under the upper pannonian unconfor­ mity approximately 300 m deeper than the bizovac oil field (fig. i ). drillstem test (dst) carried ou t in the lap of the reservoir resulted in 6 m3jday of oil, proving the oil prospects of this area. the top of the reservoir was de termined 50 j11 deeper than predicted. in a vertical sequence some of lithological sctt ings were determined analogous to the known lithology of bizovac field (basement gneiss breccia, basalt, diabase, tufrite, upper cretaceous mudstone, 13adennian siltstones, breccia gacesa & mesic. 1994). the reservoir rocks benckljucne rijeci: kalibriranje scizmickog profila, sintets­ ki seizmogram, seizm icki atributi, kljucni seizmicki profil etalon. saietak poslupcirna priblizavanja paramctara sintctskog scizmogram<l busotine well-i seizm ickom profilu i obralno, ponovnom obradom seizmickog profila ~ i s parametrima si ntetskog seizmograma, llspo stavlja se visok stupanj korelativnosti po verlikali cime se omogucava precizno post(tvljanjc busotine na odgovarajuci seizlllicki trag, te prenosenje inforrnacija u prostor izvan busotine. dalji postllpci sll rezultirali kljllcnim seizmickim profilom (etalon) kao ulazom u 3d seizrnicke postupke. prirnjena provedenih postupaka u slozenim poljima i 1czis(ima koja karak(erizira pukotinska supljikavost i hidrotennalnc promjene ce smanjiti rizik busenja horizolllalne, bocnodrenazne busotine koja bi trebala utvrd iti proizvodne mogucnosti otkrica bizovacki cree takoder sc llkazllje na prostor sjeveroistocno od bllsotine well 1 kao prostor s boljim ko lektorskim svojstvima. alh the pannonian unconfo rmity are characterised by fracture porosity and hydrothermal allerat ion. the techno logical procedures app li ed during the workover test operations have not prov ided any data e ither on the reservoir pressure or on the well produc­ tion potential. to reduce the risk and to facilitate the choice of deve lopment plans for the bizovac eret discove ry two problems had to be solved: the productivity of palaeouplift, and the detailed reinterpretation or wcll-l and the seismic data. the above mentioned characteristics resulted in vely complex lithological and reservoir rock properties, and it is necessary for further development to evaluate the possible changes wi thin the reservoir rocks (fig. 2) . to th is end all the current ly available computer techniques (hard ware & software) have been used. i ina (lcl., naftapjin, reservoir engineering and field development department. sllbiceva 29, hr~ i{)(x)o zagreb, croat ia. 2 ina d.d., naftaplin, geologica l exploration & development division, subiccva 29, hr -i 0000 zagreb, croatia . 228 " ' ~" l_ 10 , ~r', f'(~ i i~ '~f' !57'0 -'w:i_ ~4't~' oo"""'~' o~~_~. i 'f ~.;..;...;.-.~~--, well i i >_i 'i-li! ~~~" ..... com'll-u~l~d ~y s. gd("'" , compu te,i r)v ~l )\" ',., fig. i upper panllonian unconformity map. 2. processing and interpret ation the only possibility at our disposal was to make morc detailed analyses of lhe seismic data, applying special seismic processing methods and their combina­ tions. applying (he velocity data from the bizovac oil field resulted in a 50 m error when the entry point in the assumed reservoir top (target) was predicted. therefore, new velocity surveys and vertical seismic profiling (vsp) measurements were performed in well-i. the results of vsp measurements were used to check the seismic velocity survey and to compare it with a syn­ thetic seismogram. sonic logging was carried out from 350 m and den­ sity log [rom 1009 m down to the total depth. for the missing intervals the logs from onc well of the bizovac field well were also used in order to create the synthetic logs. w c!j-j iml t '"' w j '=, " " ::i m, k2'> ,en 0 !d~ -21oc m~ ~~ "'" , geologia croatic;] 49/2 transfer of thc identified well data to the seismic line was performed as follows: 1. checking the seismic velocity surveys only five shot points out of 12 shot points used in the velocity survey were suitable for thc time/depth conversion, while the remaining points would have caused too large distortion on the sonic log curve. 2. synthetic seismogram implementation of density log of another well was proved to be belle i' than the application of the computed "gardener's" density log. the synthetic seismogram was generated by applying various filters. filtering with 20 hz filters (50% matching) provided the best matching along the entire wellbore length with the existing migrated seismic line. 3. seismic reprocessing the seismic linc reprocessing was done with a minimum phase. matching of the reproccssed line and the synthetic seismogram was beuer, but still not satisfactory. 4. intervention by applying the ricker wavelet the 20 hz ricker wavelet was used [or final intervention on thc synthetic seismogram. 5. sliding the synthetic seismogram the well is locat­ ed approximately 50 m cram the seismic profile trace. the best matching of the synthetic seismogram and seismic line was achieved by sliding the synthct­ ic seismogram from 132 elf on seismic line to 142 elf. the comparison with the vsp tracc also indicat­ ed that the results were very good (fig. 3). 6. the analyses of seismic attributes the following seismic attributes were analysed: phases, amplitudes and frequencics. along the seismic section only amplitude changes have been observed. the ampli­ tudes are highcr (in range from 4500 6000) in the central part of the paleouplift, while on both flanks they arc lower (1500 0 4500) (fig. 4). fig. 2 geological crossscc(ion of (he bizovac field and bizovacki erc( location. gacesa & mesic: seismic line calibration ii main reference for the rational exploration and ... 229 the amplitudes of the cap rock (shale) are the same along the pa1aeoup!ift. higher amplitudes of the reservoir lithology cou ld be an indicator of the less fractured reservoir rocks . the decreasing velocity and density in highly fractured reservoirs results in decreasing amplitudc values. am plitudes analyses alone still can not be used to distinguish good reservoir areas from non­ reservoir, or poor reservoir rocks. further improve­ ment will occur when analysing the amplitude versus offset (a vo) and by analyses of acoustic impedance along seismic line i. 3. conclusion and recommendation analysis of a "key" seismic line previously deter­ mined with syntheti c seismogram makes possible more (2t) 1000 1100 1200 1300 tij 1400 cl 0:: 1500 f5 1600 1700 1600 fig. 3 synthetic .sei.srnogram procedure on the bizovacki cre! location. precise and reliable determination of the top of the reservoir and allows the transfer of the well "proper­ ties" to the seismic line. in this case it is possible to state that south-west of the well -1 and on the north-east side of the bizovacki cret pajaeouplift, there are morc favourable reservoir rocks than in the central part of the paleoup!ift. 'fhe results of this procedure can be summarised in the fo llowing: better understanding the petroleum geological model of bizovacki cret locality; better planning and con trolling of the slim hole (re­ entry) drilling project; better matching of all the available seismic lines in the prospect area with seismic line 1. this procedure alone is still insufficient to locate a new well with a high degree of certainty. using slleh ·6000 "500 fig. 4 in terpretation of magnified amplitude section of seismic line i. 230 procedures in complex reservoirs (characte rised by fracture porosity), will be very useful in planning the three-dimens ional (3~) seismic surveys as a basis for locating other wells, and for determining the develop­ mcnt plan with optimally spaced wells. acknowledgement the aut hors would li ke to thank to ina dd., nana­ plin for permission to publish this paper. thanks are also offered to colleagues marija vidovic and z. budanovic for the special seismic processing, and to m. saler, z. durie , b. n iko li c and n. filipovic for their contribution in preparing this article by using various pc-software. geologia croatica 49/2 4. reference gacesa. s. & mesic, i. (1994): usc of fundamental ambient analyses in the field reservoir develop­ ment by mean s of optimal vsp survey geometry planing.nana, 45/2, 123127, zagreb. ovaj rad posvećujem članovima velebitsko–kapelske ekipe (1962–1980) – kolegama anti ivanoviću, leonu nikleru, branku sokaču, ivanu galoviću i stjepanu markoviću s kojima sam zajedno sudjelovao u izradbi osnovne geološke karte 1:100.000 u velebitu, lici, velikoj i maloj kapeli i ogulinskome kraju. tada su se, prvenstveno prema mikrofosilima, a među njima i bentičkim foraminiferama, provele prve detaljnije stratigrafske raščlambe jurskih i krednih naslaga u krškim dinaridima. to je bilo polazište za kasnija paleontološko–stratigrafska istraživanja koja su rezultirala mnogobrojnim znanstvenim radovima, pa tako i ovim radom. stratigraphy and palaeobiogeography of mesozoic benthic foraminifera of the karst dinarides (se europe) ivo velić this paper is dedicated to the members of the velebit–kapela team (1962–1980) – my colleagues ante ivanović, leon nikler, branko sokač, ivan galović and stjepan marković. together we produced a basic geological map at 1:100,000 scale, and performed detailed stratigraphical subdivision of the jurassic and cretaceous rocks of velebit mt., lika, velika and mala kapela mts. and the ogulin area. based on benthic microfossils – foraminifera and dasyclad algae, this was the first such subdivision in the dinarides. that work represented a foundation for subsequent palaeontological–stratigraphic investigations which resulted in numerous scientific papers, of which the present paper is included. geologia croatica 60/1 1–113 18 figs. 26 pls. zagreb 2007 key words: benthic foraminifera, chronostratigraphy, biostratigraphy, palaeobiogeography, mesozoic, karst dinarides, adriatic carbonate platform, slove­ nia, croatia, bosnia and herzegovina, montenegro. croatian geological survey, sachsova 2, hr-10000 zagreb, croatia; e-mail: ivo.velic@hgi-cgs.hr abstract the adriatic carbonate platform (adcp), was a separate shallow­ marine depositional system characterized by a lack of terrigenous input and was connected to gondwana towards the south via gav­ rovo–tripolitza or apulia. it existed for approximately 120 my, from the early jurassic (pliensbachian/toarcian) to the end of the creta­ ceous, resulting in a 4000–6500 m thick succession of almost pure carbonates. however, this is part of a thicker (>8000 m) sequence of predominantly carbonate rocks which forms the karst dinarides, and was deposited during more than 270 my – at least from the carbonif­ erous (moscovian) to the late eocene. among many different groups of fossil organisms, benthic foraminifera are especially abundant and well preserved, so they, along with calcareous algae (dasycladales), are the most important fossils used for age determination and stratigraphic subdivision of shallow­marine carbonate deposits. within the 257 determined taxa belonging to different foramini­ feral families which lived through the mesozoic, numerous differ­ ent index fossils occur in assemblages indicating various ages: early triassic, anisian, carnian, norian–rhaetian, late sinemurian, early and late pliensbachian (carixian and domerian), early and late aalenian, early and late bajocian, early and late bathonian, callo­ vian, early and late oxfordian, kimmeridgian, tithonian, berriasian, valanginian, late hauterivian, late barremian, early and late aptian (bedulian and gargasian), early and late albian, early, middle and late cenomanian, turonian, coniacian, santonian, early and late campanian and early and late maastrichtian. a total of 64 biostratigraphic units – biozones of different catego­ ries, from subzone to superzone, were defined within the stratigraphic interval from the carnian to the late maastrichtian. this enabled very detailed biostratigraphic subdivision of the carbonate deposits within the karst dinarides. this is one of the most precise sequences, not only in this area, but also among former shallow marine deposits of the entire neotethyan realm in the present mediterranean region. the palaeobiogeographic characteristics of biotopes and the composition of foraminiferal assemblages during the mesozoic were controlled by the position of the study area within the neotethyan bio­ provinces. until the albian, this area represented part of the southern neotethyan bioprovince, while from the cenomanian to its final disin­ tegration at the end of the cretaceous it belonged to a separate, central mediterranean neotethyan bioprovince. 2 geologia croatica 60/1 1. introduction........................................................................................................................................................ 2. foraminiferal taxa and assemblages in chronostratigraphic succession............................................................. 2.1. triassic....................................................................................................................................................... 2.1.1. early triassic – scythian (induan and olenekian)............................................................................. 2.1.2. middle triassic.................................................................................................................................. 2.1.3. late triassic...................................................................................................................................... 2.2. jurassic....................................................................................................................................................... 2.2.1. early jurassic.................................................................................................................................... 2.2.2. middle jurassic................................................................................................................................. 2.2.3. late jurassic...................................................................................................................................... 2.3. cretaceous.................................................................................................................................................. 2.3.1. early cretaceous............................................................................................................................... 2.3.2. late cretaceous................................................................................................................................. 3. biostratigraphy................................................................................................................................................... 3.1. previous investigations.............................................................................................................................. 3.2. biostratigraphic zonation and subdivision................................................................................................. 3.2.1. late triassic...................................................................................................................................... 3.2.2. early jurassic.................................................................................................................................... 3.2.3. middle jurassic................................................................................................................................. 3.2.4. late jurassic...................................................................................................................................... 3.2.5. early cretaceous............................................................................................................................... 3.2.6. late cretaceous................................................................................................................................. 4. palaeobiogeography of mesozoic benthic foraminifera of the karst dinarides................................................. 4.1. triassic....................................................................................................................................................... 4.2. jurassic....................................................................................................................................................... 4.3. cretaceous.................................................................................................................................................. 4.4. correlation................................................................................................................................................. 5. review of the results.......................................................................................................................................... 6. references.......................................................................................................................................................... appendix: list of taxa..................................................................................................................................... 1. introduction benthic foraminifera are among the most important fos­ sil organisms for age determination and stratigraphic subdivision of shallow­marine carbonate deposits of the mesozoic karst dinarides. some taxa (or even entire assemblages) enable chronostratigraphic determination, because their stratigraphic ranges were evaluated by correlation with ammonite zones, mostly in the western mediterranean realm, e.g. moroccan atlas, spanish bet­ ic cordillera, and especially in france: pyrenees, aqui­ taine and paris basins, provence, western alps, etc. the jurassic lituolids can be highlighted, as an example of stratigraphically well determined forms; especially the orbitopsella spp. of the lower jurassic of morocco (septfontaine, 1984), hauranids and pfenderinids in the middle jurassic and kurnubiinids in the upper jurassic of the western mediterranean in europe and northern africa (bassoullet, 1997), orbitolinids in the hauterivian–aptian (‘urgonian’) deposits of se france (e.g. clavel et al., 1995; arnaud et al., 1998; schroeder et al., 2002), or within upper bar­ remian–middle cenomanian stratigraphic range in the prebetian platform of se spain (castro et al., 2001). other examples include the orbitolinids and alveolinids of vraconian and cenomanian deposits of the eastern pyrenees (bilotte, 1985), etc. contents 2 3 4 5 5 5 6 6 9 11 12 12 16 20 20 21 21 22 24 27 29 33 38 38 38 42 46 48 51 59 3velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... during the last couple of decades, new and sophis­ ticated methods have been introduced into stratigraphic and palaeontologic investigations, e.g. dating on the basis of isotopic or palaeomagnetic analyses, or deter­ mination of dna within fossil organisms, and many papers were published. recently, when the term pal­ aeontology has become increasingly substituted by the term palaeobiology, the purpose of a paper such as this, i.e. the stratigraphy of benthic foraminifera within the shallow­marine mesozoic carbonates of the adriatic car­ bonate platform, may be questioned. this is especially true since papers on similar topics in the neighbouring carbonate platforms were published more than 10 years ago (e.g. chiocchini et al., 1994: apenninic plat­ form). however, this is the first synthesis of the results of stratigraphic investigation of benthic foraminifera of the adcp in the last fifty years, especially on upper triassic to uppermost cretaceous deposits. the adriatic carbonate platform (adcp, fig. 1) is a term for a palaeogeographic entity which existed from the early jurassic to the end of the cretaceous, and which forms an important part of the karst dinarides. however, shallow­marine environments mostly charac­ terised by carbonate deposition existed for much longer in the study area. the oldest carbonate rocks cropping out in the karst dinarides are carboniferous in age, while almost continuous carbonate deposition lasted for some 220 my, from the middle permian to the eocene (velić et al., 2002). before the individualization, i.e. during the late palaeozoic and early triassic, the area of the future karst dinarides represented part of the gondwanian epicontinental shelf (see discussion in vlahović et al., 2005). from the middle triassic to the middle early jurassic, the area of the present karst dinarides was part of the huge, more or less isolated carbonate plat­ form (free from continental influences), which covered a large part of present southern and central europe. this was called the southern tethyan megaplatform by vlahović et al. (2005), and it disintegrated into several smaller, relatively isolated carbonate platforms during late sinemurian to late toarcian times. these smaller platforms included, among others, the adriatic, apulian and apenninic platforms (vlahović et al., 2002, 2005; dragičević & velić, 2002). the adriatic carbonate platform s.str. existed from the late early jurassic (pliensbachian/toarcian) to near the end of the cretaceous, when it was finally destroyed. it represented an almost completely isolated shallow­ marine depositional system, which was probably con­ nected towards the s and se to the kruja and gavrovo– tripolitza platforms (vlahović et al., 2005). during the mesozoic period the platform continuously migrated from the southern tethyan realm, where it was placed during the early jurassic, towards the n and ne, to the northern areas of this palaeo­ocean in the late maas­ trichtian. it was surrounded by deep­marine basins: the bosnian to the n and ne, krasta–budva–cukali to the se, ionian–adriatic–belluno to the s and sw and the slovenian basin to the nw. during the late maastrichtian and palaeogene, the platform significantly disintegrated, and carbonate depositional environments were established only within restricted areas, particularly several narrow carbonate ramps along flysch–molasse basins surrounding uplifted areas of the former adcp (vlahović et al., 2002). despite significant tectonic disintegration, which had already begun in the mesozoic and lasted practi­ cally throughout the cenozoic, the adriatic carbonate platform is one of the best preserved fossil carbonate platforms in the world (except for its marginal parts). unlike the aforementioned areas of the western mediterranean, which were characterized by interfinger­ ing of shallow­marine and open­marine/basinal facies, allowing chronostratigraphic determination of many foraminiferal taxa, no such possibilities occurred on the adcp. this platform was geotectonically relative­ ly stable throughout its existence, without significant palaeogeographic and palaeoenvironmental changes. therefore, intra­platform shallow­marine deposits were only sporadically accompanied by temporary drowned­ platform environments containing ammonites or other pelagic organisms enabling stratigraphic correlation. however, platform margin and slope facies, which inter­ fingered with basinal deposits, were overlain by young­ er, tertiary and quaternary clastic rocks, or by nap­ pes composed of palaeozoic and older triassic rocks. therefore, numerous taxa of benthic foraminifera, the chronostratigraphic range of which were already deter­ mined in other peri­mediterranean platforms, represent a very important, and sometimes even the only tool for the stratigraphic subdivision of the karst dinarides. this paper considers benthic foraminiferal taxa and assemblages from the stratigraphic viewpoint, as well as examining their importance for the stratigraphic determination of shallow­marine carbonate sequences, especially for geological mapping. in addition, the pal­ aeobiogeography of the most important (mostly index fossils), is presented. major attention was given to the so­called larger foraminifera, while smaller forms were discussed only if they represent index fossils. 2. foraminiferal taxa and assemblages in the chrono­ stratigraphic succession some periods in the geological history of the adriatic carbonate platform and its basement were character­ ized by the predominance of certain groups of benthic foraminifera. for example, the early and middle tri­ assic were characterized by amodiscids, late triassic by involutinids, and the jurassic by lituolids. during the cretaceous, diversification was significant. several groups of smaller foraminifera characterized the neo­ � geologia croatica 60/1 comian. from the barremian to the middle cenoma­ nian the most important foraminifera were orbitolinids accompanied by ataxophragmiids, lituolids, cyclammi­ nids as well as frequent miliolids, cuneolinids, etc. the evolution of soritids and alveolinids can be traced from the aptian, while orbitoids and siderolitids were impor­ tant during the campanian and maastrichtian. genera and species, either individually or within foraminiferal assemblages, are mostly presented in their order of occurrence. 2.1. triassic as the shallow­marine deposits accumulated during the triassic belong to the basement of the adriatic carbon­ fig. 1 recent area covered by the adriatic carbonate platform deposits. �velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... ate platform, only their general foraminiferal taxa and assemblages are presented. after the late permian glo­ bal biological crisis, when most of the late palaeozoic foraminifera (including the most important group, the fusulinids) became extinct, there was a gradual restora­ tion of shallow­marine environments, which were eco­ logically suitable for the existence of benthic foraminif­ era. during the early triassic, carbonate deposition was characterized by an important terrigenous influence, and mixed carbonate–siliciclastic environments were not favourable as niches allowing the larger foraminif­ era to thrive. therefore, the early triassic represented a period during which smaller foraminifera (mostly ammodiscids) predominated. in the middle triassic, shallow­marine environments characterized by ‘pure’ carbonate deposition were restored, but in some areas temporary lateral replacement by deeper­marine car­ bonate–volcanoclastic deposits occurred. from a palae­ ontological point of view, an abundant flora of calcar­ eous algae, including in particular the diploporaceaen family of the dasycladales, characterized these environ­ ments. reefal–perireefal environments favourable for the development of corals, hydrozoans, molluscs, etc. were also very common. benthic foraminifera were not very important, but the most frequent were still ammo­ discids, meandrospirids, endotriadids, duostominids etc. during the late triassic involutinids were the most important foraminifera. 2.1.1. early triassic – scythian (induan and olenekian) general characteristics: early triassic foraminifera were not systematically investigated in the karst dinarides, although they are very abundant at some localities. their occurrence is of great stratigraphic value, because they frequently represent the only palaeontological evidence for the determination of lower triassic deposits. therefore, the most fre­ quent genera and index species are mentioned here. foraminiferal assemblage: cyclogyra mahayeri, meandrospira pusila, ammodiscus parapriscus, arenovidalina chialingchiangensis, glomospirella triphonensis and numerous other undeterminable smaller foraminifera, mostly ammodiscids. discussion: this assemblage is characteristic of the early triassic of the karst dinarides in the induan– olenekian stratigraphic range. in his comprehensive and detailed treatise of croatian triassic stratigra­ phy, which also included the ne parts of the adcp basement in the vicinity of karlovac grgasović (2003) separated two foraminiferal zones: the older cyclogyra mahayeri zone and younger meandros­ pira pusila zone, and he cited most of the species listed above. some of these forms were also listed in some older papers discussing the platform area, e.g. kochansky-devidé & pantić (1966) and pantić-prodanović (1975). 2.1.2. middle triassic general characteristics: anisian and ladinian forami­ niferal assemblages show great differences, both in their composition and stratigraphic value. while anisian deposits contain several index species, none have so far been discovered in the ladinian sedi­ ments, where smaller foraminifera predominate. 2.1.2.1. anisian foraminiferal assemblage: meandrospira dinarica, pilammina densa, pilamminella semiplana, hoy­ enella gr. sinensis, duostomina alta, neoendothyra reicheli, turriglomina mesotriassica, arenovidalina chialingchiangensis, endotriadella wirtzi, fron­ dicularia woodwardi, ammobaculites radstadtensis, aulotortus sp., haplophragmium sp., glomospira sp., glomospirella sp. and other smaller foramini­ fera. discussion: anisian index species, meandrospira dina­ rica, pilammina densa and pilamminella semiplana, are widely distributed, and have been described in the area of the karst dinarides (pantić, 1965; kochansky-devidé & pantić, 1966). they were also cited in later papers (pantićprodanović, 1975; grgasović et al., 2000; grgasović, 2003). other taxa have a wider stratigraphic range, and most of them also occur in ladinian deposits. 2.1.2.2. ladinian foraminiferal assemblage: most taxa cited in the ani­ sian assemblage also occur in ladinian deposits, except for anisian index forms. however, the most frequent are specifically undeterminable forms of diplotremina and duostomina. discussion: ladinian foraminifera have not been pre­ viously systematically determined because of their scarcity and the lack of index forms. therefore, stratigraphic determination and distinction between anisian and ladinian deposits has been based on calcareous algal assemblages. on the basis of detailed analysis by grgasović (2003) it may be concluded that there are rare occurrences of aulotor­ tus species in the ladinian (e.g. a. praegaschei and a. sinuosus). in the present area of the karst dinar­ ides these also occur in anisian deposits, reaching maximum frequency during the norian and rha­ etian. 2.1.3. late triassic general characteristics: late triassic foraminiferal assemblages are not especially rich in genera and species. this is the result of palaeogeographic rela­ tionships, since the area of the present karst dinar­ ides was emergent from the late ladinian to the early norian (velić et al., 2002; vlahović et al., 2005). therefore, older upper triassic deposits (carnian and lower norian), can only be observed 6 geologia croatica 60/1 along the marginal parts of the platform area, e.g. in the vicinity of karlovac, from where grgasović (2003) listed rich foraminiferal assemblages. during the norian and rhaetian, limestones and early­dia­ genetic dolomites were deposited within peritidal environments. limestones mostly suffered late­dia­ genetic dolomitization, so rocks of this age, usu­ ally known as the main dolomite (hauptdolomit or dolomia principale), only sporadically contain undolomitized lenses and thinner packages of lime­ stones with late triassic fossil assemblages, includ­ ing frequent foraminifera. the most important group are involutinids, including some index species of the late triassic. 2.1.3.1. carnian foraminiferal assemblage: lamelliconus multispirus, l. procerus, aulotortus friedli, a. praegaschei, a. sinuosus, a. tenuis and numerous smaller foraminif­ era of greater, middle and upper triassic strati­ graphic range. discussion: due to emergence, carnian deposits are either missing, or are represented by terrigenous clastic sediments over much of the karst dinar­ ides. shallow­marine carbonates were only depos­ ited in some places which were not emergent, e.g. central slovenia, or the vicinity of karlovac in croatia along the ne margin, as well as komiža on the island of vis, the vicinity of trebinje in herze­ govina or in montenegro along the sw and se mar­ gins. within these rocks a carnian algal–foraminif­ eral assemblage has been discovered, including index forms foraminifera lamelliconus multispirus and l. procerus. in addition to these two forms, grgasović (2003) also cited numerous other species of smaller foraminifera. 2.1.3.2. norian foraminiferal assemblage: aulotortus friedli, a. prae­ gaschei, a. sinuosus, a. tenuis, a. tumidus, auloco­ nus permodiscoides, trocholina crassa, t. acuta and turrispirillina minima. discussion: the aforementioned species of aulotortus reached their maximum development in the late norian and rhaetian. they were documented in the regionally very well known periadriatic and central european formations of the main dolomite (haupt­ dolomit or dolomia principale) and dachstein lime­ stones of upper triassic age. in the karst dinarides, the main dolomite is of late norian and rhaetian age. in older papers (pantić, 1966/67; pantićprodanović, 1975) turrispirillina minima was described as a norian species. 2.1.3.3. rhaetian foraminiferal assemblage: triasina hantkeni, aulo­ conus permodiscoides, aulotortus friedli, a. sinu­ osus, a. tenuis, a. tumidus, a. pokornyi, trocholina crassa and t. acuta. discussion: triasina hantkeni is the index fossil of the rhaetian. the maximum frequency of the cited spe­ cies of aulotortus which appeared in the late nori­ an continued into the early rhaetian. 2.2. jurassic during the jurassic in the area of the present karst dinarides, lituolids represented the major foraminif­ eral group. they occurred in the sinemurian and had already reached their maximum in the pliensbachian. they were very frequent in the middle jurassic, when together with cyclamminids, valvulinids (especially pfenderinids), as well as other groups they represent the major fossils used for stratigraphic division. the larg­ est number of index fossil taxa occurred in bathonian deposits. during the late jurassic, the number of taxa, as well as individual specimens decreased. 2.2.1. early jurassic general characteristics: in several very important papers, septfontaine (1980, 1984, 1988; sep­ tfontaine et al., 1991) presented the best evo­ lution, classification/taxonomy, biostratigraphy and palaeobiogeography of the jurassic lituolids. subsequently bassoulet (1997), in his revi­ sion of the stratigraphic ranges of larger jurassic foraminifera, mostly lituolids, confirmed septfon­ taine’s thoughts on the early jurassic lituolids. this is especially important for the discussion of early jurassic foraminiferal assemblages, because almost all genera and species that septfontaine cited from the moroccan high atlas (fig. 2b), and bassoulet in northern africa and western europe (fig. 2c) occur in the adriatic carbonate platform (fig. 2a). how­ ever, their occurrence did not commence at the tri­ assic–jurassic boundary but later in the sinemurian. 2.2.1.1. hettangian foraminiferal assemblage: involutina liassica, duo­ taxis metula, amijiella amiji, siphovalvulina varia­ bilis and everticyclammina sp. – ?e. praevirguliana. discussion: there are no very important foraminif­ eral taxa in the hettangian deposits. therefore, the stratigraphy of this stage on the adcp is based on dasycladacean calcareous algae, mostly on species of palaeodasycladus (sokač, 2001), among which p. mediteraneus is the most frequent and ranges from the hettangian to the end of the pliensbachi­ an. involutina liassica occurs throughout the lower jurassic deposits, but only in the rocks originating at the platform margins and slopes. duotaxis metula is characterized by a stratigraphic range throughout the early jurassic, while amijiella amiji has an even wider range, from the early to middle jurassic. 2.2.1.2. sinemurian foraminiferal assemblage: (a) early sinemurian: mesoendothyra sp., siphovalvu­ lina gibraltarensis, s. colomi, s. variabilis, duotaxis 7velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... sinemurianhett. pliensbachian toarcian pliensbachian sinemurianhett. toarcian carixian domerian pliensbachiansinemurianhettangian toarcian carixian domerianearly late fig. 2 stratigraphic ranges of the early jurassic benthic foraminifera on the adcp (a) and comparison with stratigraphic ranges in high atlas (b – after septfontaine, 198�) and western europe and northern africa (c – after bassoullet, 1997). stratigraphic ranges are shown according to their duration in my (time scale after gradstein et al., 200�). a b c 8 geologia croatica 60/1 metula, amijiella amiji, everticyclammina praevir­ guliana, meandrovoluta asiagoensis, pseudocycla­ mmina sp. and involutina liassica. (b) late sinemurian: mesoendothyra sp., a. amiji, d. metula, s. variabilis, s. gibraltarensis, s. colomi, e. praevirguliana, m. asiagoensis, lituosepta recoa­ rensis, orbitopsella primaeva, haurania deserta, lituolipora termieri, planisepta compressa, agerina martana and i. liassica. discussion: the early sinemurian is characterized by the appearance of more abundant foraminiferal assemblage, but without very good index forms. the most important is mesoendothyra sp., which accord­ ing to septfontaine (1984, 1988) is the source form of the most important early jurassic lituolids in the southern tethyan bioprovince. this foraminifera has been found in many localities on the adcp, and is especially abundant in velebit mt. (tišljar et al., 1991), where it occurs in the early sinemurian. according to septfontaine (1984, 1988), two lines of early jurassic lituolids evolved from this form in the late sinemurian and pliensbachian: (1) mesoendothyra sp. – lituosepta? recoarensis – o.? primaeva – o. praecursor – o. dubari, and (2) mes­ oendothyra sp. – lituolipora termieri – planisepta compressa, which has also been confirmed on the adcp. kabal & tasli (2003) described lituoli­ pora termieri as a synonym of both paleomayncina termieri (hottinger, 1967; septfontaine, 1988) and lituolipora polymorpha (gušić & velić, 1978). the only index forms for the late sinemurian are l. recoarensis (its entire stratigraph­ ic range is within this part of the stage), accompa­ nied by o. primaeva occurring in late sinemurian and early pliensbachian. during the sinemurian h. deserta occurs which is similar to a. amiji, and is observed in the later stages (pliensbachian, aalenian and bajocian). 2.2.1.3. pliensbachian foraminiferal assemblage: (a) early pliensbachian – carixian: mesoendothyra sp., l. recoarensis, orbitopsella praecursor, o. pri­ maeva, h. deserta, a. amiji, p. compressa, l. ter­ mieri, biokovina gradacensis, bosniella oenensis, a. martana, d. metula, s. variabilis, s. gibraltarensis, s. colomi, e. praevirguliana, m. asiagoensis and i. liassica. (b) late pliensbachian – domerian: mesoendothyra sp., o. praecursor, o. ?dubari, h. deserta, a. amiji, l. termieri, p. compressa, b. gradacensis, b. oenen­ sis, d. metula, pseudocyclammina liassica, s. varia­ bilis, s. gibraltarensis, s. colomi, e. praevirguliana, m. asiagoensis, a. martana, in places calcisphaer­ ulids and i. liassica. discussion: within the carixian foraminiferal assem­ blage, the occurrence of orbitopsella species are very important. o. primaeva reached its maximum in the early carixian, o. praecursor in the late carixian, and the occurrence of the early domer­ ian index fossil o. dubari is assumed. p. liassica is an index form of the late domerian. observations of biokovinids – biokovina gradacensis and bos­ niella oenensis – are rare and mostly occur in the tectonized parts of the southern karst dinarides, so their stratigraphy may be approximated to within the pliensbachian. p. compressa reaches its maximum frequency in the domerian. l. termieri is an index form for the late sinemurian and carixian. sept­ fontaine (1980, 1988) considered the genus bos­ niella as a synonym of the genus mesoendothyra. l. recoarensis has been discovered within the ear­ liest pliensbachian (early carixian) in the karst dinarides, although occurrences are rare. this con­ firms the partial overlap of its stratigraphic range with that of o. primaeva in detailed profiles inves­ tigated in the velebit mt. area. in western tethys it is exclusively a sinemurian species, as illustrated by septfontaine (1984) and bassoullet (1997). towards the east, in italy, on the apennin­ ic carbonate platform chiocchini et al. (1994) found this form within (or even after) the strati­ graphic range of o. praecursor, in the monte sor­ genza and monte della selva columns, indicating that in the apennines l. recoarensis was definitely of carixian, and possibly even early domerian age. 2.2.1.4. toarcian foraminiferal assemblage: e. praevirguliana, mesoe­ ndothyra croatica, i. liassica, a. martana, s. varia­ bilis, s. gibraltarensis, s. colomi and m. asiagoen­ sis. discussion: due to palaeoenvironmental and sedimen­ tological circumstances, larger foraminifera have never been observed in the youngermost lower jurassic deposits of the adriatic carbonate plat­ form, nor on neighbouring platforms in the south­ ern tethyan realm. as a consequence of the intense regional extensional tectonic movements described in the introduction, the adriatic carbonate plat­ form separated from the neighbouring apulian and apenninic ones during the toarcian (vlahović et al., 2002, 2005; dragičević & velić, 2002). western areas of the adriatic carbonate platform were temporarily drowned, resulting in deposition of bioturbated mudstones and subordinate peletal– ooid wackestone/packstones, the so­called ‘spotty limestones’. this event correlates with a toarcian oceanic anoxic event (jenkyns, 1988, 1991; vlahović et al., 2005). penecontemporaneous­ ly, the ne margin emerged, while in the se, high­ energy shallows were locally formed, characterized by deposition of beach and bar ooid grainstones. generally, depositional environments throughout the platform area were unfavourable for the growth of benthic organisms of all kinds, not only for foraminifera, which are very scarce. interesting first 9velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... occurrences of rare forms close to m. croatica were recorded in the ‘spotty limestones’, representing an age probably from the beginning of the toarcian to the beginning of the aalenian. this species had the major part of its range in the middle jurassic (to the early bathonian), and its maximum in the bajocian. the toarcian represents the end of the stratigraphic range of i. liassica, which has never been found in the inner part of the platform. 2.2.2. middle jurassic general characteristics: before late 1980’s, middle jurassic platform carbonates were considered to be quite unfossiliferous, except for the part belonging to the bathonian. however, new investigations proved that they are relatively rich in a number of fossils. according to the number of determined fossil taxa, they represent the most fossiliferous jurassic depos­ its (fig. 3). among the larger foraminifera, lituolids, hauraniids, cyclamminids and pfenderinids were determined. most of these taxa represent index fos­ sils, most frequently in the upper aalenian, lower bajocian and bathonian deposits. 2.2.2.1. aalenian foraminiferal assemblage: (a) early aalenian: mesoendothyra croatica, gutni­ cella cayeuxi, pseudocyclammina maynci, amijiella amiji, haurania deserta, redmondoides lugeoni, siphovalvulina variabilis and everticyclammina sp. (b) late aalenian: m. croatica, g. cayeuxi, p. maynci, a. amiji, h. deserta, r. lugeoni, s. variabilis, timi­ donella sarda, spiraloconulus perconigi and everti­ cyclammina sp. discussion: all cited taxa were determined in the s and se parts of the adcp, and locally in the ne, marginal parts of the platform. in these areas mid­ dle jurassic carbonates are mostly represented by ooid, bioclastic and intraclastic limestones depos­ ited in the higher water energy environments of the platform shallows. they are relatively rich in their foraminiferal assemblages. however, in the central, relatively deeper and more restricted areas, predom­ inantly thick­bedded mudstones were deposited, characterized by relatively rare findings of the cited taxa, with the exception of m. croatica which is rel­ atively frequent. among the stratigraphically more important species, g. cayeuxi has a stratigraphic bathonianbajocianaalenian callovian fig. 3 stratigraphic ranges of the middle jurassic benthic foraminifera on the adcp and dasycladalean alga selliporella donzellii for comparison with foraminiferal ranges. 10 geologia croatica 60/1 range through most of the aalenian, and is accom­ panied by s. perconigi and t. sarda in the upper aalenian deposits. these two latter species have not been previously determined within the middle jurassic carbonates of the adcp. 2.2.2.2. bajocian foraminiferal assemblage: (a) early bajocian: m. croatica, p. maynci, g. cayeuxi, t. sarda, a. amiji, h. deserta, r. lugeoni, s. variabi­ lis, spiraloconulus giganteus, s. perconigi, pseudo­ dictyopsella jurassica, marzoella ficcarellii, proto­ peneroplis striata, nautiloculina sp. – probably n. gr. oolithica, trocholina sp. and everticyclammina sp. (b) late bajocian: m. croatica, s. giganteus, a. amiji, h. deserta, r. lugeoni, s. variabilis, p. striata, par­ avalvulina complicata, pseudoeggerella elongata, pfenderella arabica, praekurnubia crusei, n. gr. ?oolithica, trocholina gr. alpina, trocholina sp. and everticyclammina sp. discussion: forms typical of aalenian deposits also occur in the earliest bajocian, including g. cayeuxi, s. perconigi and t. sarda. above these, during the end of the early and the beginning of the late bajo­ cian, p. jurassica and m. ficcarellii (index species) occur with n. gr. ?oolithica. although bassoul­ let (1997) indicated a stratigraphic range for s. giganteus from the early bajocian to the early callovian, with the most definite occurrences in the bathonian, this form only occurs in the bajocian on the adcp. m. croatica reaches its maximum in the early bajocian, while p. striata is at the begin­ ning of its stratigraphic range, which extends until the end of the jurassic in the adcp. in the topmost levels of bajocian carbonates, p. arabica and t. gr. alpina were determined, and these also occur in the younger stages. the index form of younger upper bajocian deposits is p. complicata. p. elon­ gata occurs in the continuous succession from top­ most upper bajocian beds and are more common in the bathonian. trocholina species of the t. alpi­ na–elongata group were reported within the genus andersenolina (neagu, 1994). this view has been followed by some, e.g. bucur et al. (2004), but not by all authors, e.g. chiocchini et al. (1994), radoičić (2005), etc. until recently s. giganteus, p. jurassica, m. ficcarellii, p. complicata and p. elongata were not known within the bathonian, or generally in the middle jurassic in the area of the adcp. they have very recently been reported by velić (2005). the first occurrences of p. crusei occur in transitional beds at the base of the batho­ nian. by the end of the early bajocian selliporella donzellii appears, and its stratigraphic range includes the earliest late bathonian. this dasyclad alga is very important for the stratigraphy of the middle jurassic shallow­marine carbonate succession of the karst dinarides. 2.2.2.3. bathonian foraminiferal assemblage: (a) early bathonian: m. croatica, s. variabilis, r. luge­ oni, p. striata, p. arabica, t. gr. alpina, p. elongata, p. crusei, paleopfenderina salernitana, p. trochoi­ dea, nautiloculina gr. oolithica and everticyclam­ mina sp. (b) late bathonian: s. variabilis, r. lugeoni, p. stria­ ta, p. arabica, t. gr. alpina–elongata, p. elongata, p. crusei, p. salernitana, p. trochoidea, alzonella cuvillieri, satorina apuliensis, satorina mesojurassi­ ca, kilianina blancheti, orbitammina elliptica, n. gr. oolithica and everticyclammina sp. discussion: the bathonian is the richest stage within middle jurassic deposits of the adcp with regard to the abundance of larger foraminifera. within this assemblage index fossils of the early bathonian are absent, but the age is reliably indicated between the beginning of the stratigraphic range of p. salerni­ tana and the first occurrence of the following index fossils of the late bathonian: a. cuvillieri, s. apuli­ ensis, s. mesojurassica, k. blancheti and o. ellip­ tica. p. elongata, s. mesojurassica and a. cuvillieri have only a single record in the adcp area (velić et al., 1995), but have not been previously illustrat­ ed. o. elliptica has been observed here for the first time. p. salernitana is the most frequent and most widely distributed bathonian species on the adcp. s. apuli­ ensis, and other bathonian species are less common. 2.2.2.4. callovian foraminiferal assemblage: p. salernitana, s. variabi­ lis, r. lugeoni, p. striata, p. arabica, t. gr. alpina– elongata, p. crusei, n. gr. oolithica, mohlerina basi­ liensis, kurnubia jurassica, probably chablaisia chablaisensis and everticyclammina sp. discussion: there are no specific index forms in the callovian sediments: this assemblage has a ‘transi­ tional’ character with taxa that can be traced from older middle jurassic to late jurassic stages: r. lugeoni, p. crusei, p. arabica, p. striata and t. gr. alpina–elongata. this assemblage also comprises the beginning of the m. basiliensis range (tasli, 1993 and chiocchini et al., 1994, this form being attributed to archaeosepta). by the end of the callo­ vian the first kurnubias occur, e.g. k. jurassica. ch. chablaisensis has only been observed at one locality in biokovo mt., within tectonically very disturbed deposits also containing p. crusei. other index forms are absent, but neighbouring older outcrops are of bathonian age. ch. chablaisensis is only previously known from oxfordian deposts in the adcp area (velić & tišljar, 1988; tišljar & velić, 1993; velić et al., 1995). at the aforementioned localities other oxfordian forms are also absent. therefore, it could be concluded that this occurrence probably indicates somewhat older, 11velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... probably callovian or even bathonian deposits (see fig. 3). 2.2.3. late jurassic general characteristics: among the foraminifera in the upper jurassic carbonates of the adcp, those belonging to the genus kurnubia are the most important. in spite of the occurrence of either other index species or those species that are very abundant in certain levels, the stratigraphic range of different species from late callovian to the middle tithonian designates this genus as typically indicating a late jurassic age (fig. 4). several species of the genus kurnubia have been described in the perimediter­ ranean area, while on the adcp the following spe­ cies have been documented: k. palastiniensis, k. wellingsi (e.g. radoičić, 1966; gušić, 1969a, b; velić, 1977, etc.) and k. jurassica (gušić, 1969a, b). 2.2.3.1. oxfordian foraminiferal assemblage: (a) early oxfordian: pseudocyclammina lituus, siphovalvulina variabilis, redmondoides lugeoni, pfenderella arabica, praekurnubia crusei, mohle­ rina basiliensis, protopeneroplis striata, kurnubia palastiniensis, k. jurassica, karaisella uzbekista­ nica, trocholina alpina, t. elongata, t. gigantea, chablaisia chablaisensis, nautiloculina oolithica, n. circularis and everticyclammina virguliana. (b) late oxfordian: labyrinthina mirabilis, kurnubia wellingsi, k. jurassica, k. palastiniensis, k. uzbekis­ tanica, ch. chablaisensis, n. oolithica, n. circu­ laris, t. alpina, t. elongata, t. gigantea, p. lituus, s. variabilis, r. lugeoni, p. arabica, p. crusei, m. basiliensis, p. striata and e. virguliana. discussion: in the assemblage cited above, the only form which represents an index fossil for the oxfor­ dian is k. uzbekistanica (occuring in quiet subtidal and/or lagoonal facies). t. gigantea, determined in middle oxfordian deposits is significant, but is very rare (mostly in higher energy and tempestite facies). kurnubia forms predominate, and k. palastiniensis is the most frequent species, while maximum fre­ quency was also achieved by t. alpina, t. elongata and c. chablaisensis. the latter form disappeared in the late oxfordian, and it frequently occurs in the tempestitic grainstones. the beginning of the stratigraphic range of l. mirabilis and k. wellingsi is considered to represent the approximate boundary between the early and late oxfordian. n. circula­ ris appeared by the end of the early oxfordian, and reached its maximum in the late oxfordian. 2.2.3.2. kimmeridgian foraminiferal assemblage: (a) early kimmeridgian: s. variabilis, e. virguliana, r. lugeoni, p. arabica, p. crusei, p. striata, k. jura­ ssica, k. palastiniensis, k. wellingsi, l. mirabilis, t. alpina, t. elongata, m. basiliensis, p. lituus, coni­ tithoniankimmeridgianoxfordian fig. � stratigraphic ranges of the late jurassic benthic foraminifera on the adcp. 12 geologia croatica 60/1 cocurnubia orbitoliniformis, alveosepta jaccardi, kilianina? rahonensis and parurgonina caelinensis. (b) late kimmeridgian: s. variabilis, e. virguliana, r. lugeoni, p. striata, t. alpina, t. elongata, m. basil­ iensis, k. palastiniensis, k. wellingsi, p. lituus, c. orbitoliniformis, a. jaccardi, k.? rahonensis and p. caelinensis. discussion: index forms for the kimmeridgian deposits of the adcp are c. orbitoliniformis and a. jaccar­ di, and partially k.? rahonensis, which has a strati­ graphic range through the major part of the kim­ meridgian, and p. caelinensis in the terminal early and late kimmeridgian. however, the latter two species can also be observed in lower tithonian deposits. l. mirabilis, p. crusei, p. arabica and k. jurassica disappeared in the early kimmeridgian. for stratigraphic correlation, the important dasyclad algae are pseudoclypeina cirici (index fossil of the early kimmeridgian), as well as the first occurrence of the late jurassic species clypeina jurassica. dasyclad algae are distributed throughout the adcp area from the middle kimmeridgian to the transi­ tional level between the tithonian and berriasian. 2.2.3.3. tithonian foraminiferal assemblage: (a) early tithonian: s. variabilis, e. virguliana, r. lugeoni, p. striata, t. alpina, t. elongata, m. basil­ iensis, k. palastiniensis, p. lituus, k.? rahonensis and p. caelinensis. (b) late tithonian: e. virguliana, r. lugeoni, p. stria­ ta, t. alpina, t. elongata, m. basiliensis, k. palas­ tiniensis, p. lituus, protopeneroplis ultragranulata, anchispirocyclina lusitanica and/or a. neumannae. discussion: in the youngest upper jurassic carbonates of the adcp there are almost no typical index forms of foraminifera. very rarely, specimens of anchispi­ rocyclina occur, which are specifically almost impossible to determine because of significant mic­ ritization, probably belong to index tithonian forms including a. lusitanica and/or a. neumannae. all the cited species except the trocholinas, r. lugeoni, p. lituus and p. ultragranulata disappeared in titho­ nian: first p. caelinensis then k.? rahonensis in the early tithonian, k. palastiniensis at the beginning of the late tithonian, and a. lusitanica/neuman­ nae at the end of tithonian. according to bucur (1993), p. ultragranulata has a wider stratigraphic range from the middle tithonian to the early bar­ remian, but on the adcp it has only been found in the late tithonian and early berriasian. 2.3. cretaceous the orbitolinids are the most important cretaceous larg­ er foraminifera. on the adcp they appear in the late barremian, and inhabited the platform, with temporary breaks, until the end of the cretaceous. almost all orbi­ tolinid species have stratigraphic importance. however, if orbitolinids are the most important, cuneolinids and miliolids were the most abundant cretaceous foraminif­ era. besides these groups, early cretaceous foraminife­ ral assemblages include numerous smaller forms – invo­ lutinids, ataxophragmiids, novalesinids, and cyclammi­ nids. from the aptian to the late cretaceous, alveoli­ nids and nezzazatids became more and more frequent, while during the late cretaceous soritids, fischerinids, pavonitids, dicyclinids, rhapydioninids and rotaliids increased noticeably. orbitoidids and siderolitids were important on the platform slopes and in the deeper intra­ platform troughs formed in the late cretaceous. 2.3.1. early cretaceous general characteristics: the end of the jurassic and the beginning of the cretaceous are character­ ized by the emergence of a large part of the central adcp (velić et al., 2002). deposits from areas with continuous deposition were late­diagenetically dolomitized, while in the shallowest areas early­dia­ genetic dolomites were formed. therefore, within these unfavourable conditions foraminiferal assem­ blages were reduced, especially those of the larger foraminifera. until the first occurrence of orbi­ tolinids in the late barremian, smaller foraminifera were predominant. the richest foraminiferal assem­ blages were determined from early aptian and albian deposits (fig. 5). during the late aptian, there was a decrease in the number of foraminife­ ral taxa, as a result of the regional relative sea­level fall and frequent short periods of emergence (e.g. vlahović et al., 2005), as well as longer local emergent phases, e.g. in western istria (velić et al., 1989). the most important studies of palaeontology, bios­ tratigraphy and modern systematics of orbitolinids are those of schroeder (particularly schroeder, 1975, 1979). these two papers on the general evo­ lutionary trends, definitions and origin of orbitoli­ nids from the early aptian to middle cenomanian resulted from his earlier studies (e.g. schroed­ er, 1962, 1964a, b, c). the evolutionary line, which commenced in the early aptian, with praeorbitoli­ na cormyi – p. wienandsii – mesorbitolina lotzei has also been documented on the adriatic carbon­ ate platform (velić & sokač, 1978a, b; velić, 1988). 2.3.1.1. berriasian foraminiferal assemblage: (a) early berriasian: mohlerina basiliensis, trocholi­ na alpina, t. elongata, pseudocyclammina lituus, protopeneroplis ultragranulata, mayncina bulgari­ ca and charentia cuvillieri. (b) late berriasian: m. basiliensis, t. alpina, t. elon­ gata, p. lituus, m. bulgarica, c. cuvillieri, montsa­ levia salevensis, meandrospira favrei, haplophrag­ moides joukowskyi, vercorsella tenuis, v. campo­ saurii and praechrysalidina sp. 13velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... fig. � stratigraphic ranges of the early cretaceous benthic foraminifera on the adcp. 1� geologia croatica 60/1 discussion: in the transitional level between the titho­ nian and berriasian, and for the early berriasian, the index form is p. ultragranulata. the berriasian represents the end of the stratigraphic range of m. basiliensis. the beginning of this stage is character­ ized by the first occurrences of m. bulgarica (with a stratigraphic range throughout the early creta­ ceous) and infrequent observations of c. cuvillieri (the stratigraphic range of which continued into the late cretaceous). first occurrences of small prae­ chrysalidina sp. (which may be ancestors of prae­ chrysalidina infracretacea that ranges from the late barremian until the late albian), were documented from upper berriasian to lower barremian depos­ its. near the end of the berriasian, important species of smaller foraminifera occur, including m. saleven­ sis, m. favrei, h. joukowskyi, v. tenuis and v. cam­ posaurii, which reached their maximum in the val­ anginian. 2.3.1.2. valanginian foraminiferal assemblage: trocholina sagittaria, t. delphinensis, t. alpina–elongata, p. lituus, m. bul­ garica, c. cuvillieri, m. salevensis, m. favrei, h. joukowskyi, vercorsella scarsellai, v. camposaurii, v. tenuis, sabaudia minuta, as well as novalesia sp. and praechrysalidina sp. discussion: index fossils for the valanginian of the adcp are m. salevensis, h. joukowskyi, m. favrei, v. tenuis, and v. camposaurii, which is particular­ ly common. all these forms appear near the end of the berriasian, and disappear in the early hauteriv­ ian. there are additional forms that first occur in the valanginian, and others that are also present in younger intervals of the early cretaceous, includ­ ing t. sagittaria, v. scarsellai, and very rarely s. minuta. throughout the valanginian, trocholinids of the t. alpina–elongata group, p. lituus and prae­ chrysalidina sp. are still present. t. delphinensis was determined exclusively in valanginian depos­ its. although valanginian deposits contain the larg­ est number of index fossils of all the neocomian units, more detailed stratigraphic subdivision of val­ anginian deposits is not presently possible since all these index forms, together with numerous calcare­ ous algae (dasycladales), have stratigraphic ranges spanning the whole of the valanginian. 2.3.1.3. hauterivian foraminiferal assemblage: (a) early hauterivian: t. gr. alpina–elongata, t. sagit­ taria, m. bulgarica, c. cuvillieri, s. minuta, m. sale­ vensis, h. joukowskyi, m. favrei, v. tenuis, v. campo­ saurii, v. scarsellai, novalesia distorta, nezzazata germanica and praechrysalidina sp. (b) late hauterivian: t. gr. alpina–elongata, t. sagit­ taria, m. bulgarica, c. cuvillieri, s. minuta, n. ger­ manica, vercorsella laurentii, v. scarsellai, debari­ na hahounerensis, novalesia producta, n. distorta, campanellula capuensis, pseudonummoloculina sp. and praechrysalidina sp. discussion: n. distorta occurs in the early hauterivian. the late hauterivian is characterized by the disap­ pearance of t. gr. alpina–elongata. the entire stage is characterised by several species which continued from the valanginian, e.g. t. sagittaria, v. scarsell­ ai, m. bulgarica, c. cuvillieri and s. minuta. species appearing for the first time in the latest hauterivian, and occurring throughout the younger stages of the early cretaceous are d. hahounerensis, n. producta and v. laurentii. this group also contains species of pseudonummoloculina, similar to p. aurigerica. nezzazata germanica represents an index species, but is very rare, while in the latest hauterivian and transitional beds to the barremian c. capuensis is very common. 2.3.1.4. barremian foraminiferal assemblage: (a) early barremian: n. distorta, n. cornucopia, n. producta, vercorsella wintereri, v. scarsellai, v. lau­ rentii, m. bulgarica, t. sagittaria, d. hahounerensis, s. minuta, spiroloculina cretacea, rumanoloculina robusta, belorussiella textilarioides, glomospira watersi, pseudonummoloculina sp., praechrysalidi­ na sp. and involutinids – ‘involutina’ sp. (b) late barremian: all taxa from the early barremian are present but are also accompanied by rectodic­ tyoconus giganteus, palorbitolina lenticularis, tro­ cholina molesta, t. odukpaniensis, vercorsella are­ nata, derventina filipescui, neotrocholina fribur­ gensis, n. aptiensis, nautiloculina broennimanni, n. cretacea, charentia cuvillieri, praechrysalidina infracretacea, pseudonummoloculina aurigerica and ‘involutina’ sp. discussion: during the earliest barremian, there were no significant changes in the foraminiferal assem­ blage compared to the late hauterivian. this marks the beginning of the stratigraphic range of some species which are typical of the early creta­ ceous, as well as s. cretacea, r. robusta, b. texti­ larioides and v. wintereri, which were documented in the barremian of the western part of the adcp by cvetko tešović (2000). c. cuvillieri also occurs in these deposits, although it has not been observed in the lower barremian deposits. near the end of the barremian, orbitolinids occur as the first genuine larger foraminifera on the adcp. the oldest forms belong to r. giganteus observed along the northern platform margin between banja luka and kupres, and p. lenticularis which is widely distributed across the platform. velić & sokač (1978a) proposed that the stratigraphic range of p. lenticularis began, before the occurrence of the early aptian praeorbitolinids, indicating the late barremian. this approach was later confirmed by gušić (1981), who compared the dimensions of 1�velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... the proloculuses and embrional apparatuses of this species, and documented the gradual increase in these dimensions from older, barremian, to younger, aptian palorbitolinids. furthermore, in the absence of other criteria within the palorbitolinid limestones of the adcp, the size of the proloculus can even be used to determine the boundary between the bar­ remian and the aptian (gušić, 1981). in addition, several other foraminifera of a wider stratigraphic range have been determined – trocholi­ na sagittaria, t. molesta, t. odukpaniensis, ver­ corsella arenata, pseudonummoloculina aurigerica and p. infracretacea, as well as all the taxa found in the lower barremian deposits. at the very end of the barremian derventina filipescui, neotrocholina friburgensis, n. aptiensis, nautiloculina broenni­ manni and n. cretacea occur before the first appear­ ance of the praeorbitolinids indicating the beginning of the aptian. 2.3.1.5. aptian foraminiferal assemblage: (a) early aptian: p. lenticularis, r. giganteus, paleo­ dictyoconus actinostoma, praeorbitolina cormyi, p. wienandsi, mesorbitolina lotzei, voloshinoides mur­ gensis, sabaudia briacensis, s. minuta, choffatella decipiens, d. filipescui, n. friburgensis, n. aptiensis, t. molesta, t. odukpaniensis, pfenderina globosa, pseudolituonella conica, d. hahounerensis, m. bul­ garica, p. infracretacea, v. laurentii, v. scarsellai, v. arenata, n. producta, n. distorta, n. cornuco­ pia, n. broennimanni, n. cretacea, c. cuvillieri, p. aurigerica, glomospira urgoniana, g. watersi, s. cretacea, r. robusta, archaealveolina sp. and ‘invo­ lutina’ sp. (b) late aptian: mesorbitolina parva, m. texana, n. aptiensis, d. hahounerensis, m. bulgarica, p. infracretacea, sabaudia auruncensis, s. capitata, s. minuta, v. laurentii, v. scarsellai, v. arenata, novalesia angulosa, n. producta, n. distorta, n. cornucopia, haplophragmoides globosus, archal­ veolina reicheli, p. aurigerica, nezzazata isabellae, n. simplex, g. urgoniana, g. watersi, s. cretacea, r. robusta and orbitolinopsis aquitanica. discussion: occurrence of the first orbitolinids near the end of the barremian marks the beginning of the dominance of these larger foraminifera on the adcp which lasted until the middle cenomanian. one of the most frequent and widely distributed species is p. lenticularis, which reaches its maximum during the early aptian. in some localities it is so abundant that it has lithogenetic value as some tempestite lay­ ers are composed almost exclusively of tests of this foraminifera (see cover page of this issue). in the undisturbed succession of lower aptian deposits, the first part of the evolutionary trend of orbitolinids can be traced, which, according to schroeder (1962, 1964a, b, c, 1975, 1979), commences in the early aptian and ends in the middle cenomanian. this was confirmed on the adcp by velić & sokač (1978a) and velić (1988), where the aptian forms occur in the stratigraphic succession of p. cormyi – p. wienandsi – m. lotzei (early aptian) – m. parva – m. texana (late aptian). the early aptian foraminiferal assemblage also contains other index fossils, including v. murgensis, s. briacensis, c. decipiens, d. filipescui, n. fribur­ gensis, n. aptiensis, p. globosa and p. conica. oth­ ers, characterized by a wider stratigraphic range throughout the early cretaceous include p. auriger­ ica, n. broennimanni and n. cretacea, as well as an alveolinid form very close to a. reicheli, which has a stratigraphic range through the late aptian and early albian. furthermore, numerous specimens of involutinids also occur, but due to intense recrystal­ lization, can only be determined as ‘involutina’ sp. the evolutionary trend of genuine orbitolinids is continued in the late aptian by the new species m. parva and m. texana. among other orbitolinids in the youngermost aptian deposits o. aquitanica was also determined. the most abundant foraminifera are of somewhat wider stratigraphic ranges, e.g. d. hahounerensis, m. bulgarica, p. infracretacea, s. minuta, s. capi­ tata, s. auruncensis, v. laurentii, v. scarsellai and v. arenata, including the first occurrences of h. globosus (or trochaminoides coronus according to chiocchini et al., 1994) and n. simplex. a. reicheli, which can also be observed locally in mes­ orbitolinid tempestites, reaches its maximum in the aptian. smaller forms, together with some still not completely determined forms, cited by cvetko tešović (2000) include g. urgoniana, g. watersi, n. isabellae, s. cretacea and r. robusta. in the late aptian, species of novalesia disappeared except for n. angulosa. 2.3.1.6. albian foraminiferal assemblage: (a) early albian: mesorbitolina pervia, m. subconca­ va, m. parva, m. texana, paracoskinolina sunni­ ladensis, cuneolina pavonia, c. parva, c. sliteri, sabaudia dinapolii, s. minuta, s. auruncensis, s. capitata, nezzazatinella picardi, pseudonummolo­ culina heimi, p. aurigerica, s. cretacea, r. robusta, g. urgoniana, n. isabellae, n. simplex, d. hahoune­ rensis, h. globosus, m. bulgarica, p. infracretacea, a. reicheli, v. laurentii, v. scarsellai, v. arenata, n. angulosa and orbitolinopsis sp. cf. o. aquitanica. (b) late albian: ‘valdanchella’ dercourti, neoiraquia insolita, n. convexa, simplorbitolina broennimanni, paracoskinolina fleuryi, p. sunnilandensis, c. pavo­ nia, c. parva, scandonea pumila, s. phoenissa, n. simplex, n. isabellae, n. gyra, ?trochospira avni­ melechi, ?biconcava bentori, n. picardi, p. heimi, p. aurigerica, s. cretacea, s. minuta, s. auruncen­ 16 geologia croatica 60/1 sis, v. laurentii, v. scarsellai, n. angulosa, g. urgo­ niana, p. infracretacea, protochrysalidina elongata, ovalveolina maccagnoae and ?sellialveolina viallii. discussion: albian deposits on the adcp contain rich foraminiferal assemblages dominated by different miliolids. among other larger foraminifera, the most important are the orbitolinids because of both their stratigraphic value and abundance in certain levels. the most important event for determination of the boundary between upper aptian and lower albian deposits is the first occurrence of species of cune­ olina, including c. pavonia, c. parva and c. sliteri which are certain indicators of the beginning of the albian. albian deposits also contain numerous foraminifera known from barremian (or even ear­ lier) and aptian sediments: p. aurigerica, d. hahou­ nerensis, m. bulgarica, p. infracretacea, a. reicheli as well as all previously mentioned species of sabaudia and vercorsella. during the early albian, the widely distributed species p. heimi and n. picar­ di, occur for the first time. these, together with the cuneolinids, continue to the late cretaceous in the area of the adcp. of these, p. aurigerica is the most common. according to cvetko tešović (2000), lower albian carbonates also contain smaller foraminifera, including g. urgoniana, n. isabellae, s. cretacea and r. robusta. within the orbitolinid assemblage, the mesorbitolinids m. parva and espe­ cially m. texana are important. these, together with p. lenticularis, constitute the most abundant early cretaceous larger foraminifera on the adcp. m. texana is also frequently lithogenic, especially along the ne platform margin from banja luka towards jajce and kupres. the largest, most advanced mes­ orbitolinids are m. pervia and m. subconcava, and these are also index fossils for the albian. in the area of the adcp, the latter species represents the final member of the mesorbitolinid part of the evo­ lutionary trend of the ‘genuine’ orbitolinids (after schroeder, 1975). these deposits rarely con­ tain specifically undeterminable (mostly micritized) specimens of orbitolinopsis sp., as well as p. sun­ nilandensis. upper albian deposits are characterized by two zones with orbitolinids: the first one in the older part, and the second one in uppermost part of the vraconian, below the cenomanian. in the first orbit­ olinid­rich zone, ‘v.’ dercourti, n. insolita, s. broen­ nimanni and p. fleuryi were determined, while the second one contains only ‘v.’ dercourti and n. con­ vexa. during the late albian s. pumila and s. phoe­ nissa occur together with other foraminifera, and in the youngermost part there is also p. elongata and o. maccagnoae. from the early albian some forms with wider stratigraphic ranges continued, of which the most important include the pseudonummolo­ culinids, cuneolinids and sabaudias cited above. in the terminal part of the late albian, and the transi­ tional level to the cenomanian, n. simplex occurs together with the first appearance of other nezzaza­ tids including n. gyra, trochospira avnimelechi and biconcava bentori, which reached their maximum in the cenomanian. 2.3.2. late cretaceous general characteristics: foraminiferal assemblag­ es in the adcp upper cretaceous deposits are not regularly distributed (fig. 6). if the frequency and abundance of all taxa within specific stages were analysed statistically, cenomanian foraminiferal assemblages would probably be the richest in the entire succession of shallow­marine carbonates. in contrast, the turonian is characterized by an evi­ dent decrease in the diversity and abundance of foraminiferal assemblages, as a consequence of the prominent global sea­level rise in the youngermost cenomanian and oldermost turonian, first recog­ nised in the adcp by gušić & jelaska (1990, 1993). this sea­level rise resulted in the temporary drowning of a major part of the adcp (see jelas­ ka et al., 1994; vlahović et al., 1994, 2003, 2005; tišljar et al., 2002; velić et al., 2002). another earlier regionally important sea­level rise was determined within the youngermost albian and oldest cenomanian deposits on the island of cres (husinec et al., 2000; korbar et al., 2001) and some neighbouring areas. after restoration of the shallow marine environments and ecosystems in the late turonian, a gradual recolonization of benthic foraminifera took place, but this was not character­ ized by such a richness of taxa and specimens as during the cenomanian. however, the next resur­ gence in the foraminiferal assemblages took place in the late santonian and, especially, the campanian. maastrichtian assemblages were characterized by a relative decrease in the number of taxa, which is not surprising considering that by this time the platform had already largely disintegrated and most of it was emergent, resulting in a significant decrease of the shallow­marine areas. 2.3.2.1. cenomanian foraminiferal assemblage: foraminifera determined within the cenomanian deposits of the adcp can generally be divided into two groups. the first group comprises forms which originated in the early cretaceous or the cenomanian, and some of them continue into younger periods. forms from the early cretaceous include cuneolina pavonia, c. parva, pseudonummoloculina heimi, spirolo­ culina cretacea, nezzazatinella picardi, nezzazata simplex, n. gyra, trochospira avnimelechi, bicon­ cava bentori, charentia cuvillieri and scandonea pumila. since cenomanian they were accompanied by biplanata peneropliformis, nezzazata conica and rotalia mesogeensis, as well as cuneolina conica, murgeina apula and spiroloculina robusta, which 17velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... pseudorhipidionina murgiana c on ia ci an turoniancenomanian s an to ni an campanian m aa st ric ht ia n fig. 6 stratigraphic ranges of the late cretaceous benthic foraminifera on the adcp. 18 geologia croatica 60/1 can be found also in younger upper cretaceous deposits. the second group comprises foraminifera that are either index fossils for some parts of the cenoma­ nian, or were found only in some levels of the ceno­ manian of the adcp although they are of a wider stratigraphic range in the cretaceous. in this group, the following forms are characteristic: (a) early cenomanian: ovalveolina maccagnoae, o. crassa, ?sellialveolina viallii, praealveolina iberi­ ca, p. simplex, cisalveolina lehneri, orbitolina gr. sefini–concava, conicorbitolina conica, c. cuvil­ lieri, c. gr. corbarica–conica, pseudocyclammina rugosa, trocholina arabica and pastrikella biplana. (b) middle cenomanian: conicorbitolina conica, c. gr. corbarica–conica, c. cuvillieri, o. gr. sefini–con­ cava, p. iberica, c. lehneri, o. crassa, chrysalidina gradata, nummoloculina? regularis, pseudolituo­ nella reicheli, pseudorhapydionina dubia, merlin­ gina cretacea, peneroplis turonicus, pastrikella bal­ canica and p. biplana. (c) late cenomanian: c. gradata, n.? regularis, p. reicheli, p. balcanica, p. dubia, cisalveolina fraasi, vidalina radoicicae, v. hispanica, murgeina ceno­ mana, pseudorhapydionina laurinensis, pseudorhi­ pidionina casertana, p. murgiana, m. cretacea, peneroplis parvus and p. turonicus. discussion: the maximum abundances of p. heimi, c. pavonia, c. parva and nezzazatids, some of which previously occur in the late albian (velić & sokač, 1979), and some in the early cenomanian, are particularly important in the first group. among the second group, the alveolinids o. maccagnoae, o. crassa, s. viallii, c. lehneri, p. simplex and p. iberica are stratigraphically very important for the early cenomanian. index fossils for the middle cenomanian alone are absent, except for p. biplana which is known as the early to middle cenomanian form (cherchi & schroeder, 1980, 1985), and is frequent in middle cenomanian beds with p. balcanica on the adcp. reliable definition of this part of the cenomanian is based on the overlapping stratigraphic ranges of the cited orbitolinids, which ended their stratigraphic range near the end of the middle cenomanian, together with foraminifera of characteristic middle to late cenomanian strati­ graphic range, including c. gradata, n.? regularis, p. reicheli, p. balcanica and p. dubia. index fossils of the late cenomanian are c. fraasi, v. radoicicae, v. hispanica, p. laurinensis, p. casertana, p. mur­ giana and p. parvus. polšak et al. (1982) cited s. minuta as being of early cenomanian age, although they commented that their early cenomanian foraminiferal assem­ blage does not differ from that of the late albian. therefore, the question of the position of the exact boundary between the albian and the cenomanian, as well as the exact stratigraphic range of this form, remains open. 2.3.2.2. turonian foraminiferal assemblage: (a) early turonian: p. heimi, c. pavonia, c. parva, s. cretacea, n. simplex, n. gyra, n. conica, t. avnime­ lechi, b. bentori, n. picardi and m. apula. (b) late turonian: p. heimi, cuneolina compressa, c. pavonia, c. parva, s. cretacea, n. simplex, n. gyra, n. conica, t. avnimelechi, b. bentori, n. picardi, m. apula, pseudocyclammina sphaeroidea, monchar­ montia apenninica and m. compressa. discussion: the early turonian is characterized by platform drowning, resulting in impoverishment of the shallow­marine benthic foraminifera assemblag­ es, which are mostly composed of taxa with broad stratigraphic ranges. restoration of assemblages in subtidal, lagoonal and peritidal environments took place at the end of the early and during the late turonian. the most frequent forms were those with their maximum abundance in the cenomanian, including c. pavonia, c. parva, c. conica, p. heimi, s. cretacea, n. simplex, n. gyra, n. conica, t. avn­ imelechi, b. bentori, n. picardi and m. apula. new species like p. sphaeroidea, m. compressa and c. compressa occurred in the late turonian. 2.3.2.3. coniacian foraminiferal assemblage: c. pavonia, c. parva, c. conica, c. compressa, dicyclina schlumbergeri, p. heimi, n. picardi, n. simplex, n. gyra, n. conica, b. bentori, t. avnimelechi, m. apula, m. compressa, m. apenninica, p. sphaeroidea, scandonea samnitica, accordiella conica and idalina antiqua. discussion: the coniacian foraminiferal assemblage also does not contain index forms, since most of the determined taxa first appeared in turonian or older deposits. the coniacian is characterized by the first occurrence of d. schlumbergeri, s. samnitica, a. conica and i. antiqua, the stratigraphic range of which extends into younger cretaceous stages. 2.3.2.4. santonian foraminiferal assemblage: (a) early santonian: c. pavonia, c. parva, c. conica, p. heimi, s. samnitica, p. sphaeroidea, m. com­ pressa, m. apenninica, n. simplex, n. gyra, b. ben­ tori, t. avnimelechi, n. picardi, d. schlumbergeri, m. apula, a. conica, i. antiqua, keramosphaerina ?sarda, k. tergestina, pseudorhapydionina mediter­ ranea and murgella lata. (b) late santonian: all species from the early san­ tonian and new forms: reticulinella fleuryi, dicty­ opsella kiliani, dictyopselloides cuvillieri, spirolina cretacea, minouxia lobata, broekinella neumannae, archiacina munieri, pseudolituonella marie, pseu­ docyclammina massiliensis, rotorbinella scarsellai, 19velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... stensiöina surrentina, raadshovenia salentina and orbitoides gr. hottingeri. discussion: in the early santonian, some species first appear that continue into the early campanian including, for example, k. tergestina and m. lata, or into the maastrichtian for example p. mediter­ ranea. the first occurrence of the index species m. lata in the santonian is very important (after gušić & jelaska, 1990), together with p. mediterranea, k. tergestina, r. fleuryi, s. cretacea, d. kiliani, d. cuvillieri, r. scarsellai, s. surrentina and o. gr. hot­ tingeri, which are also index fossils for the early campanian. the beginning of the stratigraphic range of k. tergestina in the early santonian is character­ ized by small specimens, among which forms indi­ cating k. sarda were observed. the largest speci­ mens of k. tergestina occur exclusively in upper­ most santonian and lowermost campanian deposits. b. neumannae and a. munieri occur for the first time in the late santonian–early campanian foraminif­ eral assemblage of the adcp. polšak et al. (1982) and venturini (2005) also cited r. salentina from the santonian–campanian assemblages. due to the pronounced similarity of late santonian and early campanian assemblages it is not easy to reliably establish the boundary between these two stages. another, relatively new problem, is connect­ ed to the general division of younger upper creta­ ceous deposits of the adcp. strontium isotope anal­ ysis performed by steuber et al. (2005) resulted in revision of the stratigraphic ranges of the majority of larger benthic foraminifera index forms, and con­ sequently the stratigraphy of the coniacian–maas­ trichtian deposits of the island of brač as determined by gušić & jelaska (1990). according to this investigation m. lata occurred in the late coniacian, p. mediterranea and a. conica had a stratigraphic range from the late coniacian to the early campa­ nian, and k. tergestina and calveziconus lecalvezae occur in the early campanian (their first occurrence would mark the beginning of the campanian). how­ ever, venturini (2005) published results of the strontium isotope analysis from santonian–campa­ nian deposits of the slovenian–trieste karst region, according to which k. tergestina and m. lata occur in upper santonian, and c. lecalvezae in lower campanian limestones. on the basis of sr isotopes maritan et al. (2003) proposed santonian age for k. tergestina and santonian–lower campanian age for m. lata in the trieste karst area. furthermore, frijia & parente (2007) suggest on the basis of strontium and carbon isotope stratigraphy in the southern apennines, that the first occurence of m. lata occurs in the early coniacian and k. tergestina in the early campanian. here, on the adcp, the stratigraphic ranges of m. lata and k. tergestina are proposed as extending from the early santonian to the early campanian, which is in close agreement with the opinion of gušić & jelaska (1990). 2.3.2.5. campanian foraminiferal assemblage: (a) early campanian: c. pavonia, c. parva, c. coni­ ca, p. heimi, d. schlumbergeri, n. simplex, n. gyra, t. avnimelechi, b. bentori, n. picardi, p. sphaeroi­ dea, p. massiliensis, m. apula, m. apenninica, m. compressa, a. conica, p. mediterranea, s. samniti­ ca, k. tergestina, m. lata, s. cretacea, i. antiqua, m. lobata, calveziconus lecalvezae, b. neumannae, a. munieri, p. marie, reticulinella reicheli, r. fleuryi, d. kiliani, d. cuvillieri, r. scarsellai, s. surrentina, orbitoides gr. hottingeri, o. douvillei, o. tissoti and praesiderolites douvillei. (b) late campanian: c. pavonia, c. parva, n. sim­ plex, n. gyra, t. avnimelechi, n. picardi, m. apula, m. apenninica, m. compressa, d. schlumbergeri, a. conica, r. scarsellai, p. mediterranea, s. samnitica, p. sphaeroidea, p. massiliensis, r. reicheli, r. fleur­ yi, d. kiliani, d. cuvillieri, i. antiqua, c. lecalvezae, nummofallotia cretacea, praesiderolites douvillei, orbitoides douvillei, o. tissoti, o. media and pseu­ dosiderolites vidali. discussion: there is little difference between the foraminiferal assemblages of the late santonian and the early campanian, when new forms orbitoides douvillei, o. tissoti and praesiderolites douvillei appeared. most of the taxa continued to the late campanian, where they are accompanied by new forms – r. reicheli, n. cretacea and pseudosidero­ lites vidali and orbitoides media, which is also an index fossil for the maastrichtian. 2.3.2.6. maastrichtian foraminiferal assemblage: d. schlumbergeri, cuneo­ lina ketini, c. pavonia, n. picardi, m. apula, r. scarsellai, murciella cuvillieri, m. renzi, rhapydio­ nina liburnica, laffitteina mengaudi, fleuryana adriatica, o. media, siderolites calcitrapoides, omphalocyclus macroporus, lepidorbitoides minor and hellenocyclina beotica. discussion: the foraminiferal assemblage of the maas­ trichtian comprises several species which continued from earlier stages, e.g. c. pavonia, d. schlumber­ geri, n. picardi and o. media. exclusively maas­ trichtian index fossils are m. cuvillieri, m. renzi, r. liburnica, c. ketini, f. adriatica, l. mengaudi, s. calcitrapoides, o. macroporus, l. minor and h. beotica. upper campanian and maastrichtian deposits are not very common on the adcp. they occur only in its sw marginal areas – in divača area (sw slov­ enia), near trogir and dubrovnik, and on the islands of brač and hvar (s, se croatia) (marković, 1975; gušić & jelaska, 1990; jurkovšek et al., 1996; marinčić, 1997). such a restricted 20 geologia croatica 60/1 distribution is the consequence of a decreased depo­ sitional area due to the intense disintegration of the platform that began in the cenomanian, gradual emergence of its central parts and the culmination of uplift in the maastrichtian. depositional environ­ ments favourable for the development of shallow­ marine benthic communities were also frequently influenced by open marine conditions. at the ne margin of the adcp (dragičević & velić, 2002), and in the intraplatform troughs formed with­ in the central part of the platform (w bosnia and herzegovina, s croatia – velić et al., 2002), clas­ tic–carbonate deposits accumulated with predomi­ nantly planktonic foraminiferal assemblages, but also rich assemblages of benthic foraminifera, espe­ cially orbitoids and siderolitids. the sw platform margin is presently located beneath the adriatic sea, mostly covered by tertiary and quaternary deposits. however, slope deposits of maastrichtian age were determined in off­shore exploratory wells, e.g. w and sw of istria, containing orbitoid and siderolitid assemblages (veseli, 1999). 3. biostratigraphy mesozoic carbonate deposits of the adriatic carbon­ ate platform are, although partially, relatively well biostratigraphically investigated. most of the studies were restricted to relatively small areas. however, the work of radoičić (1966) is more of an attempt at the regional biostratigraphic analysis of a major part of the platform. an integrated biostratigraphic subdivision of the entire platform is presented here from the upper tri­ assic to the end of the cretaceous, based also on results of all available former investigations. lower and middle triassic deposits have not been systematically stratigraphically investigated, so there are no reliable recent data that are needed for their stratigraphic zonation. it should be noted that benthic foraminifera on the adcp were most frequently biostratigraphically ana­ lyzed together with calcareous algae. therefore, this paper represents the first zonation based exclusively on benthic foraminifera that can be used platformwide. it will be a reliable starting point not only for more detailed biozonation, but also for stratigraphic analysis and determination. 3.1. previous investigations triassic deposits of the karst dinarides have been relatively poorly investigated, and there are no data on detailed recent studies. palaeontological papers on early and middle triassic foraminiferal assemblages are scarce, and several decades old. furthermore, they usually refer to specific localities dealing with narrow stratigraphic ranges, specific taxa, etc., generally lack­ ing reliable data based on the studies of continuous stratigraphic sequences and regional correlation and synthesis. recent data can only be found in relation to upper triassic deposits, and therefore biostratigraphic zonation can be attempted from this level onwards. the previously acknowledged subdivision of the upper tri­ assic deposits of karlovac area (central croatia) is that published by grgasović (1997). however, results of older investigations from different parts of the platform are also used for biostratigraphic zonation presented in this paper. jurassic deposits have interested biostratigraphers for a long time, as witnessed by a long list of papers published since the 1960’s. authors usually followed a scheme proposed for the apennines by sartoni & crescenti (1962). for the adcp, the first such sub­ division was published by farinacci & radoičić (1964), followed by radoičić (1966), nikler & sokač (1968), gušić (1969b), gušić et al. (1971), velić & sokač (1974 – only for late jurassic), velić (1977), velić & sokač (1978a) and sokač & velić (1979a). septfontaine et al. (1991) presented a general biostratigraphic zonation of jurassic imperforate foraminifera on tethyan carbonate platforms of the mediterranean, which included the area of the adcp. velić et al. (1995) biostratigraphically subdivided younger middle and upper jurassic deposits of western istria. papers dealing with cretaceous microfossil assem­ blages are very numerous. one of the first papers illus­ trating cretaceous assemblages is that by radoičić (1960). besides stratigraphic relationships more and more attention was gradually given to biostratigraphic subdivision. some of the aforementioned papers deal­ ing with jurassic biostratigraphy also included, either partly or completely, cretaceous deposits, e.g. fari­ nacci & radoičić (1964), velić (1977), velić & sokač (1978a, b) and sokač & velić (1979a). lower cretaceous microfossil assemblages and/or bio­ zonations were also investigated, including those by velić (1973), sokač & velić (1978, 1979a, b), sokač et al. (1978), velić & sokač (1978a, b, 1979, 1980, 1983), velić et al. (1979) and fuček et al. (1995). the most detailed study of foraminiferal biostratigraphy of lower cretaceous deposits is that by velić (1988). cvetko tešović (2000) analyzed foraminiferal assemblages of the barremian, aptian and albian, while the orbitolinid biostratigraphy of the so­called mid­cretaceous (stratigraphic range early aptian–middle cenomanian), was presented by husi­ nec et al. (2000). arnaud­vanneau et al. (1991) presented stratigraphic ranges of early cretaceous ben­ thic foraminifera of the adcp and neighbouring plat­ forms, particularly the apenninic, apulian and hellenic. velić et al. (1995) presented microfossil assemblages and determined biozones within a major part of the lower cretaceous deposits of western istria. upper cretaceous deposits of the adcp are not so well biostratigraphically subdivided as jurassic and 21velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... lower cretaceous deposits. foraminiferal assemblag­ es, mostly from the adriatic coastal area and islands, were studied by mamužić & grimani (1970), mamužić et al. (1976, 1980, 1981a, b, 1982, 1983, 1984), polšak et al. (1982), gušić et al. (1988), fuček et al. (1990) and others. velić & vlahović (1994) published detailed biostratigraphic zonation of the cenomanian deposits. regionally important results on the biostratigraphy of benthic foraminifera on the adcp are presented in monographs published by gušić & jelaska (1990) and jurkovšek et al. (1996), as well as in papers by cvetko tešović et al. (2001) and korbar et al. (2001), using biozona­ tion after fleury (1980). 3.2. biostratigraphic zonation and subdivision from the introduction above it is clear that the distri­ bution of biostratigraphic investigations of benthic foraminifera over the entire adcp area is uneven. there is more or less continuous coverage over the croatian part of the platform, but papers dealing with neighbour­ ing areas are infrequent. the least investigated areas are bosnia and herzegovina and montenegro, so mostly older papers were relied on here. since lower and middle triassic rocks were rela­ tively poorly investigated, biostratigraphic zonation cannot be based exclusively on benthic foraminifera. detailed investigation of early triassic and anisian foraminiferal assemblages reveals the presence of index taxa of narrow stratigraphic range. however, ladin­ ian carbonate deposits do not contain index forms of foraminifera, and biostratigraphic zonations of middle triassic deposits are based mainly on dasyclad algae. the first such zonation was published by grgasović (2003). therefore, in this paper biozonation of the shal­ low­marine carbonate deposits of the adcp will be lim­ ited to the stratigraphic range late triassic–end creta­ ceous. the biozones and accompanying tables only list index fossils and the more important taxa for the foraminiferal assemblages in order to avoid repetition of all determined taxa previously cited in the descrip­ tion of assemblages. there are several cases when one biozone was determined as e.g. lineage zone or interval zone or partial­range zone. these zones were defined as being between the first occurrences of two index or more important foraminiferal taxa. priority was given to lineage zones, followed by partial­range zones named after species with narrow chrono­ and biostratigraphical range, and interval zones if the older taxa is of a wider stratigraphic range. for each biozone, the chronostrati­ graphic range is presented, to enable correlation of the studied deposits. however, there are cases when new investigations significantly changed the chronostrati­ graphic ranges of some important foraminiferal taxa, for example the strontium isotope analysis of the upper cretaceous deposits of the island of brač by steuber et al. (2005). such changes are important, but not essen­ tial for biostratigraphic subdivision, because it is based mostly on the order of occurrence, i.e. stratigraphic suc­ cession of individual taxa and assemblages. 3.2.1. late triassic grgasović (1997) established three biozones within the upper triassic deposits of žumberak (nw croatia): (1) clypeina besici taxon­range zone in the carnian, (2) aulotortus sinuosus interval zone of approximately norian age, and (3) triasina hantkeni taxon­range zone in the rhaetian. this subdivision is acceptable and usa­ ble throughout the adcp area. however, zonation based exclusively on benthic foraminifera will produce zones which are not completely correlatable with those based on dasyclad algae. according to the stratigraphic ranges of late triassic foraminifera the following superim­ posed upper triassic foraminiferal biozones could be established: (1) lamelliconus procerus taxon­range zone, (2) lamelliconus procerus–triasina hantkeni interval zone, and (3) triasina hantkeni taxon­range zone. 3.2.1.1. lamelliconus procerus taxon­range zone boundaries: stratigraphic range of l. procerus. index and important taxa: l. procerus, l. multispirus, aulotortus friedli, a. sinuosus, a. praegaschei and a. tenuis. stratigraphic range: carnian. discussion: within the cited assemblage only l. procer­ us and l. multispirus are index fossils, while spe­ cies of aulotortus have wider stratigraphic ranges through the late triassic. 3.2.1.2. lamelliconus procerus–triasina hantkeni interval zone boundaries: from the last occurrence of l. procerus to the first occurrence of t. hantkeni. important taxa: aulotortus friedli, a. sinuosus, a. prae­ gaschei, a. tenuis, a. tumidus, trocholina crassa and t. acuta. stratigraphic range: late carnian–early rhaetian. discussion: within well studied upper triassic depos­ its of karlovac area, grgasović (1997) sepa­ rated the a. sinuosus interval zone of norian strati­ graphic range (from the last occurrence of carnian algae clypeina besici to the first occurrence of the rhaetian foraminifera t. hantkeni). if only ben­ thic foraminifera are considered the zone would be somewhat wider, but would not contain any index forms, since the stratigraphic ranges of cited species of aulotortus commenced in the anisian. separation of this, as well as the previous zone in the area of the adcp can only be made in areas where upper triassic deposits are not dolomitized, as discussed in section 2.1.3. 22 geologia croatica 60/1 3.2.1.3. triasina hantkeni taxon­range zone, grgasović (1997) boundaries: stratigraphic range of t. hantkeni. index and important taxa: t. hantkeni, auloconus permodiscoides, aulotortus friedli, a. sinuosus, a. tenuis, a. tumidus, a. pokornyi, trocholina crassa and t. acuta. stratigraphic range: rhaetian. discussion: foraminiferal assemblages of this zone cannot be traced through the entire sequence of rhaetian deposits, due to extensive late­diagenetic dolomites, while non­dolomitized limestones can be found in alternation with dolomites in certain levels or as lenses and interbeds within dolomites. index fossils for this zone are t. hantkeni and a. permo­ discoides. 3.2.2. early jurassic due to the evident decrease of fossils during the earli­ est jurassic, biostratigraphic studies and subdivisions based exclusively on benthic foraminifera have not pre­ viously been attempted. authors dealing with jurassic biostratigraphy only defined the subzone orbitopsella praecursor in the middle part of the early jurassic with­ in the palaeodasycladus mediterraneus zone (nikler & sokač, 1968; gušić, 1969b; gušić et al., 1971; velić, 1977; velić & sokač, 1978a). biozonation within the lower jurassic deposits is presented here (fig. 7). it is based upon results of bio­ stratigraphic investigations of early jurassic lituolids made by septfontaine (1984) in shallow­marine, mostly carbonate sequences of western mediterranean, especially in the lower jurassic of the high atlas in morocco, from where hottinger (1967), described most of the early jurassic lituolid species. this subdi­ vision not only correlates well with the biostratigraphy of lituolids in velebit mt., but also in the wider area of the adcp, where more than 90% of genera and species are common and occur in the same stratigraphic ranges. therefore, the relationships between different taxa are also the same as in the lower jurassic of the high atlas (compare fig. 2 with figs. 3 & 7). 3.2.2.1. triasina hantkeni–mesoendothyra sp. interval zone boundaries: from the last occurrence of t. hantkeni to the first occurrence of mesoendothyra sp. index and important taxa: not applicable, only small valvulinids and lituolids without significant strati­ graphic value, e.g duotaxis metula, amijiella amiji, siphovalvulina variabilis and everticyclammina sp. – ?e. praevirguliana. stratigraphic range: late rhaetian–early sinemurian. discussion: during the late rhaetian and hettang­ ian, environmental conditions were very unfavour­ able for foraminifera, due to extensive coverage of the platform by tidal flats or very shallow subtidal seas. rhaetian carbonate deposits are represented by the alternation of early­ and late­diagenetic stroma­ tolitic dolomites (hauptdolomite – main dolomite formation). the hettangian deposits consist of the alternation of limestones and late­diagenetic dolo­ mites with rare intercalations of early­diagenetic dolomites. in hettangian environments dasyclad algae sporadically flourished. although all the stud­ ied sections contain benthic foraminifera there are no index species, which only occur later in the early sinemurian. therefore, this part of the sequence is marked as an interval zone. 3.2.2.2. mesoendothyra sp. lineage zone or mesoendo­ thyra sp. interval zone, septfontaine (1984) or mesoendothyra sp. partial­range zone boundaries: from the first occurrence of mesoendothy­ ra sp. sensu septfontaine (1988) to the first pliensbachiansinemurianhett. toarcian fig. 7 biostratigraphic subdivision of the lower jurassic deposits of the adcp. legend: 1) triasina hantkeni–mesoendothyra sp. interval zone; 2) mesoendothyra sp. lineage zone; 3) lituosepta recoarensis lineage zone; �) orbitopsella primaeva lineage zone: �.1) orbitopsella primaeva–lituosepta recoarensis concurrent-range subzone, �.2) lituosepta recoarensis–orbitopsella praecursor interval subzone; �) orbitopsella praecursor taxon-range zone: �.1) orbitopsella praecursor–o. primaeva concurrent-range subzone, �.2) orbitopsella praecursor abundance subzone; 6) orbitopsella praecursor–pseudocyclammina liassica interval zone; 7) pseudocyclammina liassica taxon-range zone; 8) pseudocyclammina liassica–gutnicella cayeuxi interval zone. 23velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... occurrence of lituosepta recoarensis. important taxa: mesoendothyra sp. and lituolipora termieri. stratigraphic range: transitional beds between lower and upper sinemurian. discussion: within the previously established lower jurassic, hettangian, sinemurian and pliensbachian united zone, a dasyclad algal – palaeodasycladus mediterraneus zone was separated on the adcp (e.g. farinacci & radoičić, 1964; nikler & sokač, 1968; gušić et al., 1971; velić, 1977). co­occurring foraminifera have no stratigraphic val­ ue. foraminiferal biozones were established, as sub­ zones of the aforementioned algal zone only in the upper sinemurian and pliensbachian deposits, as a result of the significant development of orbitopselli­ nids. in the biostratigraphic investigations of solely foraminiferal assemblages, this is the first time that a mesoendothyra sp. lineage zone has been deter­ mined in the lower jurassic deposits of the adcp. septfontaine (1984) marked it as an inter­ val­zone. however, according to the international stratigraphic guide (salvador, 1994) it corre­ sponds to a lineage zone, since this form represents an ancestor of l. recoarensis within the evolutionary line of early jurassic lituolids. 3.2.2.3. lituosepta recoarensis lineage zone, septfontaine (1984) or lituosepta recoarensis partial­range zone boundaries: from the first occurrence of l. recoarensis to the first occurrence of orbitopsella primaeva. index and important taxa: mesoendothyra sp., l. ter­ mieri, l. recoarensis and planisepta compressa. stratigraphic range: older late sinemurian (early lotharingian). discussion: this zone is determined as a lineage zone, and not interval or range or taxon­range zone, because l. recoarensis within the evolutionary line of early jurassic lituolids has a place between the ancestor mesoendothyra sp. and o. primaeva. the stratigraphic range of l. recoarensis on the adcp continues from this to the next zone. 3.2.2.4. orbitopsella primaeva lineage zone, septfontaine (1984) or orbitopsella primaeva partial­range zone boundaries: from the first occurrence of o. primaeva to the first occurrence of orbitopsella praecursor. index and important taxa: mesoendothyra sp., l. ter­ mieri, l. recoarensis, p. compressa and o. primae­ va. stratigraphic range: late sinemurian–early carixian. discussion: within the evolutionary line of the early jurassic lituolids, o. primaeva is a ‘transitional’ form between l. recoarensis and o. praecur­ sor. therefore, this zone is referred to as a lineage zone in the manner proposed by septfontaine (1984). in velebit mt. and lika the index fossil o. primaeva also reaches maximum abundance with­ in this zone, so it may also be defined as an abun­ dance zone. however, if one analyzes the ranges of the three most important index fossils found within lower jurassic deposits – l. recoarensis, o. primae­ va and o. praecursor – this zone can be further sub­ divided into two subzones: orbitopsella primaeva – lituosepta recoarensis concurrent­range subzone and lituosepta recoarensis – orbitopsella praecursor interval subzone. 3.2.2.4.1. orbitopsella primaeva–lituosepta recoarensis concurrent­range subzone boundaries: from the first occurrence of o. primaeva to the last occurrence of l. recoarensis. index and important taxa: mesoendothyra sp., l. ter­ mieri, l. recoarensis, p. compressa and o. primae­ va. stratigraphic range: late sinemurian–earliest carix­ ian. discussion: this biozone comprises part of the lower jurassic deposits with orbitopsella spp. in which the index species l. recoarensis and o. primaeva occur together. 3.2.2.4.2. lituosepta recoarensis–orbitopsella praecursor interval subzone boundaries: from the last occurrence of l. recoarensis to the first occurrence of o. praecursor. index and important taxa: mesoendothyra sp., l. ter­ mieri, p. compressa and o. primaeva. stratigraphic range: early carixian. discussion: this subzone comprises a part of the low­ er jurassic orbitopsella­bearing deposits containing only o. primaeva. other forms continue from zones older than this to the younger biozones. 3.2.2.5. orbitopsella praecursor taxon­range zone (sartoni & crescenti, 1962) boundaries: stratigraphic range of o. praecursor. index and important taxa: mesoendothyra sp., l. ter­ mieri, p. compressa, o. primaeva, o. praecursor and o. ?dubari. stratigraphic range: early pliensbachian (late carix­ ian). discussion: the orbitopsella praecursor biozone was first established by sartoni & crescenti (1962) in the apennines, as a subzone of the pal­ aeodasycladus mediterraneus cenozone (assemblage zone), with a stratigraphic position in the middle part of the early jurassic. this was also accepted in all investigations within the karst dinarides. within this zone, all three cited orbitopsellas occur, but the occurrence of o. dubari is dubious, although this is not critical either for chronostratigraphical or for biostratigraphical subdivision. theoretically, this 2� geologia croatica 60/1 zone might be subdivided as in the orbitopsella pri­ maeva lineage zone into two subzones: orbitopsella primaeva–orbitopsella praecursor concurrent­range subzone and orbitopsella praecursor abundance subzone. 3.2.2.5.1. orbitopsella praecursor–orbitopsella primaeva concurrent­range subzone boundaries: from the first occurrence of o. praecursor to the last occurrence of o. primaeva. index and important taxa: mesoendothyra sp., l. ter­ mieri, p. compressa, o. primaeva, o. praecursor, biokovina gradacensis and bosniella oenensis. stratigraphic range: late carixian. discussion: this zone covers part of the lower jurassic deposits in which the stratigraphic ranges of two orbitopsella index forms overlap: the first part of the o. praecursor stratigraphic range and the last part of the o. primaeva range. these forms are followed by a standard assemblage of early jurassic lituolids, the stratigraphic ranges of which continued from earlier biozones. b. gradacensis occurs in this zone for the first time. 3.2.2.5.2. orbitopsella praecursor abundance subzone boundaries: maximum abundance of the species o. praecursor. index and important taxa: mesoendothyra sp., l. ter­ mieri, p. compressa, orbitopsella ?dubari, o. prae­ cursor, b. gradacensis and b. oenensis. stratigraphic range: late carixian–earliest domerian. discussion: the index form o. praecursor is the most frequent and this zone reflects its maximum abun­ dance in the younger part of its stratigraphic range. along with o. praecursor and other typical early jurassic lituolids the occurrence of o. dubari is sup­ posed. 3.2.2.6. orbitopsella praecursor–pseudocyclammina liassica interval zone boundaries: from the last occurrence of o. praecursor to the first occurrence of p. liassica. index and important taxa: mesoendothyra sp., l. ter­ mieri and p. compressa. stratigraphic range: late pliensbachian (domerian); probably also the beginning of toarcian. discussion: although this zone contains frequent speci­ mens of l. termieri and p. compressa (general index fossils of the middle part of the early jurassic – sinemurian and pliensbachian), they cannot be used for naming this zone, since they also occur in younger and older biozones. therefore, due to the lack of index taxa this zone is defined as an interval zone. 3.2.2.7. pseudocyclammina liassica taxon-range zone, septfontaine (1984) boundaries: stratigraphic range of p. liassica. index and important taxa: l. termieri, p. compressa and p. liassica. stratigraphic range: late pliensbachian (late domer­ ian). discussion: investigation of detailed undisturbed sec­ tions of lower jurassic deposits highlighted layers where p. liassica was determined, which had not previously been recorded in the area of the karst dinarides. investigations in the western mediter­ ranean realm (hottinger, 1967; septfon­ taine, 1984) showed the exact position of this spe­ cies in the late domerian, and septfontaine (1984) founded a biozone of the same name. com­ parison of the stratigraphic ranges of index species of early jurassic foraminifera of these areas with the karst dinarides (fig. 2) shows perfect correlation, and further supports the establishment of this zone. 3.2.2.8. pseudocyclammina liassica–gutnicella cayeuxi interval zone boundaries: from the last occurrence of p. liassica to the first occurrence of gutnicella cayeuxi. important taxa: involutina liassica, agerina martana and mesoendothyra croatica. stratigraphic range: toarcian–early aalenian. discussion: cited taxa have a wider stratigraphic range within lower and middle jurassic deposits, so this zone contains no index taxa or even a large number of foraminiferal taxa as in previous biozones. this is a consequence of altered depositional environments, from mostly subtidal and lagoonal to either deeper or shallower water regions. in the nw part of the platform, regional deepening was recorded, with local terrigenous influences, while in the se part of the platform shallowing occurred, marked by depo­ sition of mostly oolitic limestones. such environ­ ments were probably not very favourable for benthic organisms, so only small, undeterminable foraminif­ era and a. martana, which has a wider stratigraphic range within lower jurassic, have been found in this zone. i. liassica has been determined only in deposits indicating an open marine influence, such as platform margins and slopes. m. croatica rarely appears in toarcian beds, but is frequent in middle jurassic deposits. 3.2.3. middle jurassic similar to the lower jurassic, the middle jurassic deposits of the karst dinarides were not biostrati­ graphically subdivided in detail. previously, one zone with three subzones had been proposed: (1) trochami­ nidae, verneuilinidae and textulariidae, (2) sellipore­ lla donzellii, and (3) pfenderinidae (farinacci & radoičić, 1964), or one zone – pfenderina salerni­ 2�velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... tana in younger part of the middle jurassic (nikler & sokač, 1968; gušić, 1969b; gušić et al., 1971), or two zones: (1) mesoendothyra croatica, and (2) selli­ porella donzellii (velić, 1977; velić & sokač, 1978a). biozonation of the middle jurassic deposits pre­ sented here (fig. 8) is based upon recent investigations, during which numerous index species have been deter­ mined. among them are taxa which were previously relatively unknown in the area of the adcp or have been discovered for the first time. 3.2.2.8. and 3.2.3.1. pseudocyclammina liassica– gutnicella cayeuxi interval zone or mesoendothyra croatica partial range zone boundaries: from the first occurrence of mesoendothy­ ra croatica to the first occurrence of g. cayeuxi. important taxa: m. croatica. stratigraphic range: toarcian and early aalenian. discussion: this interval­zone comprises jurassic deposits between the first occurrence of m. croatica to the first occurrence of g. cayeuxi, but it can also be defined as the m. croatica partial range zone, since it comprises the lowermost part of the strati­ graphic range of this taxon. m. croatica is the most important of the index species in this zone. within this weakly fossiliferous interval, a chronostrati­ graphic boundary between the lower and middle jurassic occurs, since the first occurrence of m. croatica probably took place in the early toarcian deposits. 3.2.3.2. gutnicella cayeuxi partial range zone or gutnicella cayeuxi–timidonella sarda interval zone boundaries: from the first occurrence of g. cayeuxi to the first occurrence of t. sarda. index and important taxa: g. cayeuxi, mesoendothyra croatica and pseudocyclammina maynci. stratigraphic range: middle to late aalenian. discussion: deposits of this zone and the next one could also be defined as an assemblage zone with­ in the stratigraphic range of both g. cayeuxi and t. sarda, as proposed by septfontaine et al. (1991). given the fact that the first occurrences of the cited taxa represent important biohorizons, deposits between them were defined as an interval zone. besides g. cayeuxi, p. maynci is another index form for these deposits. 3.2.3.3. timidonella sarda taxon­range zone, septfontaine (1980) boundaries: stratigraphic range of t. sarda. index and important taxa: t. sarda, m. croatica, g. cayeuxi, p. maynci, spiraloconulus perconigi and s. giganteus. stratigraphic range: late aalenian–early bajocian. discussion: t. sarda was discovered on the adcp some 20 years ago, but this fact was never published. the beginning of its stratigraphic range coincides with the last occurrence of g. cayeuxi. in the younger part of its stratigraphic range s. perconigi and s. giganteus also occur. given these relationships, this 8.1 fig. 8 biostratigraphic subdivision of the middle jurassic deposits of the adcp. legend: 1) pseudocyclammina liassica–gutnicella cayeuxi interval zone; 2) gutnicella cayeuxi partial range zone; 3) timidonella sarda taxon-range zone; �) timidonella sarda–pseudodictyopsella jurassica interval zone; �) pseudodictyopsella jurassica and marzoella ficcarellii assemblage zone; 6) pseudodictyopsella jurassica–paravalvulina complicata interval zone; 7) paravalvulina complicata taxon–range zone; 8) paleopfenderina salernitana taxon-range zone; 8.1) satorina apuliensis taxon range subzone; 9) paleopfenderina salernitana–kurnubia jurassica interval zone; 10) kurnubia jurassica lineage zone. 26 geologia croatica 60/1 zone was defined as being of latest aalenian and earliest bajocian age, according to the results of the investigations on the adcp, and comparison with well established chronostratigraphic positions of these taxa in the western mediterranean realm (e.g. bassoullet et al., 1976; septfontaine, 1980; septfontaine et al., 1991; bassoul­ let, 1997). 3.2.3.4. timidonella sarda–pseudodictyopsella jurassica interval zone boundaries: from the last occurrence of t. sarda to the first occurrence of p. jurassica. important taxa: m. croatica, p. maynci and s. gigan­ teus. stratigraphic range: younger part of the early bajo­ cian. discussion: there are no index taxa, and only two other important taxa – p. maynci and s. giganteus contin­ uing from the earlier biozone, as well as m. croati­ ca, which has a wider middle jurassic range. gener­ ally, from the biostratigraphic point of the view it is important to note that this zone marks the beginning of the stratigraphic range of the important bajo­ cian–early bathonian dasyclad species selliporella donzellii. 3.2.3.5. pseudodictyopsella jurassica and marzoella ficcarellii assemblage zone boundaries: stratigraphic ranges of p. jurassica and m. ficcarellii. index and important taxa: p. jurassica, m. ficcarellii, m. croatica and s. giganteus. stratigraphic range: middle part of the bajocian. discussion: this foraminiferal assemblage is character­ istically of high abundance but low species diversity, where the only index forms are p. jurassica and m. ficcarellii found in the central part of the bajocian succession (fig. 3), probably in transitional depos­ its between the early and late bajocian of biokovo mt., together with s. giganteus. despite this nar­ row stratigraphic range, and their occurrence in only one locality, a separate biostratigraphic unit was defined. however, the occurrence of these species in one level, could also allow these biohorizons to be termed the p. jurassica and m. ficcarellii fads (first appearance datums). since investigation of the middle jurassic deposits of the adcp represents a work in progress, new data which would confirm the establishment of this zone are expected. 3.2.3.6. pseudodictyopsella jurassica–paravalvulina complicata interval zone boundaries: from the last occurrence of p. jurassica to the first occurrence of p. complicata. important taxa: m. croatica and s. giganteus. stratigraphic range: approximately middle bajocian. discussion: deposits of this biozone contain a rich assemblage of small foraminifera, most of which belong to taxa of wider stratigraphic ranges. the maximum frequency of m. croatica was determined, so this zone could also be defined as an abundance zone. this zone comprises a major part of the strati­ graphic range of the important dasyclad species sell­ iporella donzelli, which is less frequent in deposits of the succeeding zone. 3.2.3.7. paravalvulina complicata taxon-range zone boundaries: stratigraphic range of the species p. com­ plicata. index and important taxa: p. complicata, pseudoeg­ gerella elongata and m. croatica. stratigraphic range: latest bajocian. discussion: the stratigraphic positions of p. compli­ cata and p. elongata, which were recently unknown in jurassic deposits of the adcp (velić, 2005), are the same as those defined by septfontaine (1988) for the western mediterranean. p. complica­ ta occurs somewhat earlier (probably at the very end of bajocian) than p. elongata, which occurs at the bajocian–bathonian transition and through batho­ nian. therefore this zone occurs in part of the mid­ dle jurassic deposits directly underlying the horizon characterized by the first occurrence of paleopfend­ erina salernitana, the bathonian index form which is widespread over the mediterranean. 3.2.3.8. paleopfenderina salernitana taxon-range zone sartoni & crescenti (1962) boundaries: stratigraphic range of p. salernitana. index and important taxa: p. salernitana, p. trochoi­ dea, m. croatica, p. elongata, alzonella cuvillieri, kilianina blancheti, satorina apuliensis, s. meso­ jurassica and orbitammina elliptica. stratigraphic range: bathonian–?earliest callovian. discussion: p. salernitana is connected with the begin­ ning of the bathonian on the adcp, so the lower boundary of this biozone coincides with the bajo­ cian–bathonian chronostratigraphic boundary. in the younger part of this zone the s. apuliensis sub­ zone was defined within the stratigraphic range of the late bathonian. 3.2.3.8.1. satorina apuliensis taxon range subzone boundaries: stratigraphic range of s. apuliensis. index and important taxa: satorina apuliensis, s. mesojurassica, p. salernitana, p. trochoidea, a. cuvillieri, k. blancheti, o. elliptica and p. elongata. stratigraphic range: late bathonian. discussion: this subzone comprises the younger part of the p. salernitana taxon­range zone. the stratigraph­ ic range of s. apuliensis on the adcp is longer than that of the other cited late bathonian species, so it is probable that it occurred until the end of the batho­ 27velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... nian, or even to the earliest callovian. however, the stratigraphic range of p. salernitana exceeds even the range of s. apuliensis, so it is almost certain that it also occurs in the early callovian. 3.2.3.9. paleopfenderina salernitana–kurnubia jurassica interval zone boundaries: from the last occurrence of p. salernitana to the first occurrence of kurnubia jurassica. important taxa: p. arabica, p. crusei and trocholina gr. alpina–elongata. stratigraphic range: callovian. discussion: within the interval from the last occur­ rence of p. salernitana to the first occurrence of k. jurassica the foraminiferal assemblage contains no index taxa. however, the stratigraphic range of this zone is unambiguous, since the last occurrence of p. salernitana at the adcp was in the early callovian, and the first occurrence of k. jurassica took place in the late callovian. therefore, the range of this zone is callovian. 3.2.3.10. kurnubia jurassica lineage zone or kurnubia jurassica partial­range zone or kurnubia jurassica– kurnubia palastiniensis interval zone boundaries: from the first occurrence of k. jurassica to the first occurrence of k. palastiniensis. important taxa: p. arabica, p. crusei, trocholina gr. alpina–elongata and k. jurassica. stratigraphic range: latest callovian–earliest oxford­ ian. discussion: this interval zone comprises the young­ est part of the middle jurassic and the oldest part of the upper jurassic deposits with clearly defined boundaries between two biohorizons, the first occur­ rences of two cited species of kurnubia. therefore, this zone includes the chronostratigraphic boundary between the middle and late jurassic. alternatively, this zone can also be defined as a lin­ eage zone because of the taxonomic position of k. jurassica as the first form in the evolutionary trend of kurnubians. gušić (1969a, b) discussed and illustrated k. jurassica in upper jurassic deposits of central croatia from inner platform environments of the nw parts of the former adcp. since then, this species has not been cited again in publications deal­ ing with the adcp. however, recent investigations of a series of detailed columns dispersed around the adcp, suggest that this form occurs before k. pal­ astiniensis, indicating the youngermost callovian. among kurnubians, k. jurassica represents a tran­ sitional form between p. crusei and k. palastinien­ sis. therefore the definition of this zone as a lineage zone is also approved within the evolutionary line of kurnubians: praekurnubia crusei – k. jurassica – kurnubia palastiniensis – k. wellingsi – conicokur­ nubia orbitoliniformis. 3.2.4. late jurassic hitherto biostratigraphic subdivisions of the upper jurassic deposits of the adcp were mostly based on calcareous algae (nikler & sokač, 1968; gušić, 1969b; gušić et al., 1971; velić, 1977; velić & sokač, 1974, 1978a). although benthic foraminifera were cited in these papers they were not discussed in detail. only gušić (1969b) and gušić et al. (1971), following subdivision by sartoni & crescenti (1962), separated the kurnubia palastiniensis assem­ blage zone in the older part of the late jurassic. k. palastiniensis has a stratigraphic range in the adcp from the earliest oxfordian to the late tithonian, so it has an important role in biostratigraphy of the late jurassic. therefore the major part of the upper jurassic deposits can be defined as a k. palastiniensis superzone (fig. 9). 3.2.4.1– 3.2.4.6. kurnubia palastiniensis superzone boundaries: stratigraphic range of k. palastiniensis. index and important taxa: includes all taxa cited in the next four biozones. stratigraphic range: oxfordian–late tithonian. discussion: this superzone comprises the following biozones: – kurnubia palastiniensis lineage zone, – kurnubia wellingsi lineage zone, – chablaisia chablaisensis–alveosepta jaccardi inter­ val zone, – alveosepta jaccardi partial­range zone, – parurgonina caelinensis–conicokurnubia orbitoli­ niformis concurrent range­zone, and – c. orbitoliniformis–k. palastiniensis interval zone (highest­occurrence zone). 3.2.4.1. kurnubia palastiniensis lineage zone or kur­ nubia palastiniensis partial–range zone or kurnubia palastiniensis–kurnubia wellingsi interval zone boundaries: from the first occurrence of k. palastini­ ensis to the first occurrence of k. wellingsi. important taxa: k. palastiniensis, k. jurassica, cha­ blaisia chablaisensis and karaisella uzbekistanica. stratigraphic range: early oxfordian. discussion: separation of this part of the upper jurassic deposits as a lineage zone is based on the position of k. palastiniensis within the evolutionary trend of kurnubians p. crusei – k. jurassica, k. palasti­ niensis – k. wellingsi – c. orbitoliniformis. due to the lack of foraminiferal species with a stratigraphic range confined to this interval, this unit could also be defined as an interval zone, or as the k. palas­ tiniensis partial­range zone, since it comprises the first part of the stratigraphic range of this species. within tempestites of the younger part of this zone and the older part of the next zone, ch. chablaisen­ sis, trocholina alpina and t. elongata (chablaisia– 28 geologia croatica 60/1 trocholina tempestites) are abundant in the western part of the adcp – velebit mt., gorski kotar and istria. so in this area, this part of the unit could be defined as an abundance zone. 3.2.4.2. kurnubia wellingsi lineage zone or labyrin­ thina mirabilis–karaisella uzbekistanica concurrent­ range zone or kurnubia wellingsi partial­range zone boundaries: from the first occurrence of k. wellingsi to the first occurrence of conicokurnubia orbitolini­ formis for the lineage and partial­range zones. from the first occurrence of l. mirabilis to the last occur­ rence of k. uzbekistanica for the concurrent­range zone. stratigraphic range: older part of late oxfordian. important taxa: k. wellingsi, k. palastiniensis, k. jurassica, ch. chablaisensis, k. uzbekistanica and l. mirabilis. discussion: in the aforementioned evolution of jurassic kurnubians, k. wellingsi represents a transitional form between k. palastiniensis and c. orbitolini­ formis, for the late oxfordian and the beginning of the kimmeridgian. therefore, this zone is defined as a lineage­zone. alternatively, it may be defined as a concurrent­range zone from the first occurrence of l. mirabilis to the last occurrence of k. uzbekista­ nica, the stratigraphic ranges of which overlap, or as the k. wellingsi and l. mirabilis partial­range zone. k. wellingsi is common, which supports and enables the definition of this zone. its first occurrence coin­ cides with the first occurrence of l. mirabilis, and they both continue into the next zone. 3.2.4.3. chablaisia chablaisensis–alveosepta jaccardi interval zone boundaries: from the last occurrence of ch. chablai­ sensis to the first occurrence of a. jaccardi. important taxa: l. mirabilis, k. palastiniensis, k. well­ ingsi and k. jurassica. stratigraphic range: younger part of the late oxford­ ian. discussion: there are no foraminiferal index­taxa in the uppermost oxfordian deposits. however, they could be separated as an interval zone between two biostratigraphic boundaries: the last occurrence of ch. chablaisensis and k. uzbekistanica and the first occurrence of a. jaccardi, c. orbitoliniformis and kilianina? rahonensis. 3.2.4.4. alveosepta jaccardi partial–range zone or alveosepta jaccardi–parurgonina caelinensis interval zone boundaries: from the first occurrence of a. jaccardi to the first occurrence of p. caelinensis. important taxa: l. mirabilis, k. palastiniensis, k. well­ ingsi, k. jurassica, a. jaccardi, c. orbitoliniformis and k.? rahonensis. stratigraphic range: early kimmeridgian. discussion: this foraminiferal assemblage is currently the richest known in the kimmeridgian of the adcp. most of the taxa have a wide stratigraphic range, both those occurring for the first time in younger zones of the middle jurassic, and those first occur­ ring in the oldest late jurassic zones. a. jaccardi, c. orbitoliniformis and k.? rahonensis occur here for the first time, but they are not index forms, since their stratigraphic ranges continue into younger zones. since former biostratigraphic zonations of the adcp deposits were mostly based on rich calcar­ eous algal assemblages it should be noted that this zone covers the stratigraphic range of pseudocly­ peina cirici. 1−6 oxfordian kimmeridgian tithonian fig. 9 biostratigraphic subdivision of the upper jurassic deposits of the adcp. legend: 1–6) kurnubia palastiniensis superzone: 1) kurnubia palastiniensis lineage zone; 2) kurnubia wellingsi lineage zone; 3) chablaisia chablaisensis-alveosepta jaccardi interval zone; �) alveosepta jaccardi partial-range zone; �) parurgonina caelinensis–conicokurnubia orbitoliniformis concurrent range zone; 6) conicokurnubia orbitoliniformis–kurnubia palastiniensis interval zone (highest-occurrence zone); 7) kurnubia palastiniensis–protopeneroplis ultragranulata interval zone. 29velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... 3.2.4.5. parurgonina caelinensis–conicokurnubia orbitoliniformis concurrent range zone or parurgonina caelinensis partial–range zone boundaries: from the first occurrence of p. caelinensis to the last occurrence of c. orbitoliniformis. important taxa: k. palastiniensis, k. wellingsi, c. orbi­ toliniformis, a. jaccardi, l. mirabilis, k.? rahonen­ sis and parurgonina caelinensis. stratigraphic range: middle and late kimmeridgian. discussion: there are no index forms in this foraminif­ eral assemblage. the upper boundary is marked by the last occurrence of a. jaccardi and c. orbi­ toliniformis, and this approximately corresponds to the kimmeridgian–tithonian chronostratigraphic boundary, and the beginning of the stratigraphic range of dasyclad alga clypeina jurassica. 3.2.4.6. conicokurnubia orbitoliniformis–kurnubia palastiniensis interval zone (highest-occurrence zone) boundaries: from the last occurrence of c. orbitolini­ formis to the last occurrence of k. palastiniensis. important taxa: k. palastiniensis, p. caelinensis and k.? rahonensis. stratigraphic range: early tithonian. discussion: in addition to k. palastiniensis, p. cae­ linensis and k.? rahonensis, which have their last occurrences near the end of this zone, this assem­ blage contains other forms of much wider strati­ graphic range (fig. 4). in the continuous succession of the upper jurassic, carbonate deposits of this zone can exceed 400 m thickness, and contain the middle part of the stratigraphic range of the dasyclad index fossil clypeina jurassica. 3.2.4.7. kurnubia palastiniensis–protopeneroplis ultragranulata interval zone boundaries: from the last occurrence of k. palastinien­ sis to the first occurrence of p. ultragranulata. important taxa: anchispirocyclina lusitanica, probably also a. neumannae. stratigraphic range: late tithonian. discussion: in the youngermost part of the upper jurassic deposits of the adcp a significant decrease in frequency and diversity of the foraminiferal assemblage is observed. this is largely because the peritidal environments were more favourable for abundant calcareous algae. this level is famous throughout the platform for rich assemblages and the maximum development of dasyclad species including clypeina jurassica and campbelliella stri­ ata. a. lusitanica and/or a. ?neumannae are index foraminifera but only for the youngermost part of this zone. they have only been discovered at two localities: biokovo mt., and around dubrovnik. sep­ aration of a specific zone for the entire adcp is not possible because of such very scarce and restricted observations, although theoretically it might be pro­ posed, since septfontaine et al. (1991) defined anchispirocyclina lusitanica taxon­range zone in the late tithonian (portlandian). 3.2.5. early cretaceous relatively rich foraminiferal assemblages in the lower cretaceous platform carbonate deposits of the adriatic carbonate platform have previously enabled the most detailed biostratigraphic zonation (fig. 10). zonations proposed in former studies, e.g. those by velić & sokač (1978b) and velić (1988), will represent the basis for biozonation proposed here. 3.2.5.1. protopeneroplis ultragranulata taxon­range zone (velić, 1988) boundaries: stratigraphic range of p. ultragranulata. index and important taxa: p. ultragranulata is the only index fossil, and other forms have a wider stratigraphic range, either from the jurassic into the early cretaceous or through the cretaceous, e.g. mohlerina basiliensis, trocholina alpina, t. elon­ gata, mayncina bulgarica and charentia cuvillieri. stratigraphic range: late tithonian–early berriasian. discussion: central parts of the adcp in present croatia and w bosnia were emergent during the late titho­ nian and early berriasian, while in other parts per­ itidal environments predominated, which were very unfavourable for benthic foraminifera. this is the main reason why the foraminiferal assemblage is very poor. 3.2.5.2. protopeneroplis ultragranulata–vercorsella camposaurii interval zone boundaries: from the last occurrence of p. ultragranu­ lata to the first occurrence of v. camposaurii. important taxa: there are no important taxa, since only forms of wider stratigraphic range were determined, such as trocholina alpina, t. elongata, mayncina bulgarica and charentia cuvillieri. stratigraphic range: middle and late berriasian. discussion: as for the previous zone, carbonate depos­ its of this zone were deposited in peritidal environ­ ments, and temporary subtidal environments. there­ fore the foraminiferal assemblage is also poor and without index fossils. 3.2.5.3. vercorsella camposaurii taxon­range zone (sartoni & crescenti, 1962) boundaries: stratigraphic range of v. camposaurii. index and important taxa: vercorsella tenuis, v. cam­ posaurii, montsalevia salevensis, meandrospira favrei, haplophragmoides joukowskyi, trocholina delphinensis and t. sagittaria. stratigraphic range: latest berriasian, valanginian and earliest hauterivian. discussion: sartoni & crescenti (1962) defined the cuneolina camposaurii assemblage zone with 30 geologia croatica 60/1 the stratigraphic range of valanginian–aptian. the stratigraphic range of v. camposaurii is also stated as being valanginian–aptian, but they noted that elsewhere this species is of valanginian age (provence, according to pfender, 1938) or bar­ remian age (montenegro, according to radoičić, 1960). detailed investigations on the adcp have proven that forms which correspond to the original description of v. camposaurii (sartoni & cres­ centi, 1962) are of exclusively neocomian age, with a stratigraphic range of latest berriasian–earli­ est hauterivian. so this form can be considered as an index form of the valanginian. this species has latterly been included into the genus vercorsella (arnaud­vanneau et al., 1991). almost all forms defined as c. camposaurii by velić (1973, 1977) correspond to other species of vercorsella. other additional index forms in this assemblage include v. tenuis, m. salevensis, m. favrei, h. jou­ kowskyi, t. delphinensis and t. sagittaria. other taxa have different, but wider stratigraphic ranges through the early cretaceous (fig. 5). 3.2.5.4. vercorsella camposaurii–campanellula capuensis interval zone boundaries: from the last occurrence of v. camposaurii or other index taxa of the previous zone to the first occurrence of c. capuensis. 7−10 fig. 10 biostratigraphic subdivision of the lower cretaceous deposits of the adcp. legend: 1) protopeneroplis ultragranulata taxon-range zone; 2) protopeneroplis ultragranulata–vercorsella camposaurii interval zone; 3) vercorsella camposaurii taxon-range zone; �) vercorsella camposaurii–campanellula capuensis interval zone; �) campanellula capuensis taxon-range zone; 6) campanellula capuensis– palorbitolina lenticularis interval zone; 7–10) palorbitolina lenticularis superzone: 7) rectodictyoconus giganteus and palorbitolina lenticularis assemblage zone, 8) praeorbitolina cormyi lineage zone, 9) praeorbitolina wienandsi lineage zone, 10) mesorbitolina lotzei lineage zone; 11) mesorbitolina parva lineage zone; 12) mesorbitolina texana lineage zone; 13) mesorbitolina subconcava taxon-range zone; 1�) ‘valdanchella’ dercourti partial-range zone; 1�) neoiraquia convexa taxon-range zone. 31velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... important taxa: no important taxa, only forms of wid­ er stratigraphic range, e.g. t. alpina, t. elongata and t. sagittaria. stratigraphic range: within the hauterivian. discussion: this is an interval within the hauterivian with a poor foraminiferal assemblage and no index forms. all taxa have wider stratigraphic ranges through the early cretaceous, and the cited trocholi­ nas do not occur after the hauterivian. 3.2.5.5. campanellula capuensis taxon­range zone, velić (1988) boundaries: stratigraphic range of c. capuensis. index and important taxa: c. capuensis, t. sagittaria. stratigraphic range: latest hauterivian and transition into the barremian. discussion: c. capuensis is very frequent and important in this assemblage. within the relatively poor assem­ blages in lower cretaceous deposits from the early hauterivian to the late barremian, its stratigraphic position is very important, as it represents an essen­ tial biofacies. other forms have wider, but variable stratigraphic ranges through the early cretaceous. this zone is also characterized by end of the strati­ graphic ranges of t. alpina and t. elongata. 3.2.5.6. campanellula capuensis–palorbitolina lenticularis interval zone boundaries: between two important biohorizons last occurrence of c. capuensis and first occurrence of p. lenticularis. important taxa: no important taxa, only forms of wider stratigraphic range, e.g. vercorsella lauren­ tii, novalesia distorta, n. cornucopia, n. producta, sabaudia minuta, debarina hahounerensis and t. sagittaria. stratigraphic range: early and middle barremian. discussion: in this relatively rich foraminiferal assem­ blage there are no index forms. this zone marks the beginning of the stratigraphic ranges of species that are relatively abundant in younger lower cre­ taceous deposits of the adcp – s. minuta and d. hahounerensis, as well as species of vercorsella and novalesia. 3.2.5.7–3.2.5.10. palorbitolina lenticularis superzone (taxon-range zone, husinec et al., 2000) boundaries: the stratigraphic range of p. lenticularis. index and important taxa: comprises all taxa includ­ ed in the next four biozones. it is important to note that the most important species in all of these zones is p. lenticularis. stratigraphic range: late barremian and early aptian. discussion: carbonate deposits within the stratigraphic range of p. lenticularis on the adcp represent the regionally most important biofacies level of the early cretaceous, known as the ‘lower orbitolina limestones’ (velić, 1988). within this superzone, which could also be defined as the p. lenticularis taxon­range zone (husinec et al., 2000), four zones have been determined (fig. 12): – rectodictyoconus giganteus and palorbitolina len­ ticularis assemblage zone, – praeorbitolina cormyi lineage zone, – praeorbitolina wienandsi lineage zone, and – mesorbitolina lotzei lineage zone. within deposits of the p. lenticularis superzone on the adcp, velić & sokač (1978a) and velić (1988) discovered all of the first (aptian) part of the evolutionary trend of orbitolinids according to schroeder (1975, 1979). therefore, these zones were defined as lineage zones, and were named after the first three species within the evolutionary line. 3.2.5.7. rectodictyoconus giganteus and palorbitolina lenticularis assemblage zone (velić, 1988) or palorbitolina lenticularis partial–range zone boundaries: from the first occurrence of r. giganteus and p. lenticularis to the first occurrence of praeor­ bitolina cormyi. index and important taxa: r. giganteus, p. lenticula­ ris, derventina filipescui, trocholina molesta, t. odukpaniensis, neotrocholina aptiensis, n. fribur­ gensis, nautiloculina broennimanni and n. cretacea. stratigraphic range: late barremian and beginning of the early aptian (bedoulian). discussion: r. giganteus is the index form for this zone. however, this orbitolinid was only discovered in the ne marginal area of the adcp in the vicinity of banja luka and jajce. elsewhere, over the major part of the platform, deposits of this zone are rec­ ognized as belonging to the lowermost part of the ‘lower orbitolina limestones’, where the predomi­ nant foraminifera is p. lenticularis, and praeorbito­ linids are absent (velić & sokač, 1978a). all other forms in the foraminiferal assemblage have a wider stratigraphic range, except partially n. aptien­ sis and n. friburgensis, which can also be found in the next three zones of the early aptian. 3.2.5.8. praeorbitolina cormyi lineage zone (velić, 1988) or praeorbitolina cormyi partial-range zone boundaries: from the first occurrence of p. cormyi to the first occurrence of praeorbitolina wienandsi. index and important taxa: p. lenticularis, r. gigan­ teus, p. cormyi, paleodictyoconus actinostoma, sabaudia briacensis, pfenderina globosa, d. filipes­ cui, n. aptiensis, n. friburgensis, t. molesta, t. oduk­ paniensis, n. broennimanni, n. cretacea, choffatella decipiens, voloshinoides murgensis and pseudo­ lituonella conica. stratigraphic range: early aptian (early bedoulian). discussion: p. cormyi is the only index form of this zone. p. lenticularis, predominates the assemblage 32 geologia croatica 60/1 together with forms of variable stratigraphic range through the early cretaceous, including index spe­ cies for the late barremian and early aptian – n. aptiensis and n. friburgensis, as well as species determined only from the early aptian – s. briacen­ sis, c. decipiens, v. murgensis and p. conica. at the ne margin of the adcp (mt. vlašić in central bos­ nia), the orbitolinid p. actinostoma was discovered, which is unknown in other areas of the platform, although there are data on the discovery of the genus paleodictyoconus (e.g. velić & sokač, 1978a). 3.2.5.9. praeorbitolina wienandsi lineage zone or praeorbitolina wienandsi partial­range zone boundaries: from the first occurrence of p. wienandsi to the first occurrence of mesorbitolina lotzei. index and important taxa: p. wienandsi and most of taxa cited in the previous zone. stratigraphic range: middle part of the early aptian (middle bedoulian). discussion: foraminiferal frequencies in this assem­ blage are almost identical to the assemblage of the p. cormyi zone. it is however enriched by the index form p. wienandsi, small trocholinas, and in places specifically undeterminable involutinids. p. lenticu­ laris remains a predominant form. 3.2.5.10. mesorbitolina lotzei lineage zone or mesorbitolina lotzei taxon-range zone (velić, 1988) boundaries: from the first occurrence of m. lotzei to the first occurrence of mesorbitolina parva or with­ in the stratigraphic range of m. lotzei. index and important taxa: as for the p. cormyi and p. wienandsi zones, enriched in m. lotzei and sabaudia capitata, s. auruncensis and archaealveolina sp. stratigraphic range: late early aptian (late bedou­ lian). discussion: the foraminiferal assemblage of this zone remains mostly unchanged from the composition of the previous two zones, characterized by a pre­ dominance of p. lenticularis, and enrichment in m. lotzei. poorly preserved, very micritized sections determined as archaealveolina sp. could represent a. reicheli, described from late aptian deposits (de castro, 1966, 1980, 1988). if this specific determination is proven to be correct then the occur­ rence of a. reicheli in the early aptian of the adcp would be the first occurrence of this form (velić & sokač, 1978a). the end of this zone is char­ acterized by disappearance of index forms for the late barremian and early aptian: p. lenticularis, p. cormyi, p. wienandsi, m. lotzei, p. globosa, d. filipescui, n. friburgensis, as well as other trocholi­ nids and n. broennimanni, n. cretacea, c. decipiens, s. briacensis, v. murgensis and p. conica. other forms have continuous stratigraphic ranges into the late aptian, and this zone represents the begin­ ning of the stratigraphic ranges of s. capitata and s. auruncensis. 3.2.5.11. mesorbitolina parva lineage zone or mesorbitolina parva partial­range zone boundaries: from the first occurrence of m. parva to the first occurrence of mesorbitolina texana. index and important taxa: m. parva, n. aptiensis, archalveolina reicheli, s. auruncensis, s. capitata and haplophragmoides globosus. stratigraphic range: transitional level early–late apti­ an and late aptian (gargasian). discussion: the first occurrence of m. parva was noted immediately after the last occurrence of m. lotzei in the vicinity of ogulin (central croatia). this assem­ blage contains numerous specimens of n. aptiensis, which on the adcp is regarded as an index form of the early aptian (e.g. velić & sokač, 1978a; velić, 1988; husinec et al., 2000). it is there­ fore probable that the first appearance of m. parva occurred in the final part of the early aptian and/ or transition into the late aptian. h. globosus was recorded in this zone, but is illustrated as trocham­ minoides coronus by chiocchini et al. (1994). other taxa of wider stratigraphic range through the early cretaceous were cited in the rich late aptian fossil assemblage in the previous section. among them, praechrysalidina infracretacea reached its maximum in this zone. deposits of this zone belong to the lowermost part of the biofacies known as the ‘upper orbitolina limestones’ (velić & sokač, 1978a; velić, 1988), that are regionally distributed over the adcp. it encompasses the stratigraphic range of aptian and albian mesorbitolinids, i.e. late aptian and early albian, and, from the biostratigraphic point of view, deposits of this and the two following zones. in comparison with the evolution of important cal­ careous algae, this and the following zone represent the maximum of the dasyclad alga salpingoporella dinarica radoičić (velić & sokač, 1978a). 3.2.5.12. mesorbitolina texana lineage zone (velić, 1988) or mesorbitolina texana partial-range zone boundaries: from the first occurrence of m. texana to the first occurrence of mesorbitolina subconcava. index and important taxa: m. texana, m. parva, a. reicheli, s. auruncensis, s. capitata, h. globosus and orbitolinopsis aquitanica. stratigraphic range: late aptian. discussion: m. texana is the most widespread mesorbi­ tolinid form on the adcp, with a stratigraphic range from the middle of the late aptian to the middle albian. it can be found in limestones originating in different environments, and is very abundant in lagoonal–subtidal environments and tempestites. however, there are areas with very rare occur­ rences (e.g. se croatia and islands) or where it is absent (e.g. w istria; fig. 18), due to regional shal­ lowing and emergence (velić et al., 1989, 2002). 33velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... m. parva spreads through the entire zone, and this zone represents the maximum of h. globosus and a. reicheli. o. aquitanica occurs infrequently, and is restricted to the latest aptian and earliest albian. 3.2.5.13. mesorbitolina subconcava taxon­range zone (velić, 1988) boundaries: stratigraphic range of m. subconcava. index and important taxa: m. subconcava, m. pervia, m. texana, m. parva, paracoskinolina sunnilanden­ sis, o. aquitanica, a. reicheli, sabaudia dinapolii, s. auruncensis, s. capitata, cuneolina sliteri and h. globosus. stratigraphic range: transitional level between the aptian and albian and/or the early albian. discussion: this zone forms the major part of the ‘upper orbitolina limestones’, a typical facies of the adcp (velić & sokač, 1978a; velić, 1988). the foraminiferal assemblage is domi­ nated by mesorbitolinids, among which m. parva occurs, while other species of this genus – m. tex­ ana, m. subconcava and m. pervia – reached their maximum, but disappeared at the end of this zone. within this zone the maximum of many other taxa which range through several early cretaceous zones occurred, e.g. a. reicheli, vercorsella scarsellai, v. laurentii, v. arenata, s. minuta, s. auruncensis, s. capitata, s. dinapolii and m. bulgarica. a. reicheli, v. arenata, s. auruncensis, s. capitata, s. dinapolii, rumanoloculina robusta and glomospira urgoniana disappear within this zone. in contrast, there is the first occurrence of important cretaceous foraminif­ era, which reached their maximum in the late cretaceous – cuneolina pavonia, c. parva, nezza­ zatinella picardi and pseudonummoloculina heimi. the lower boundary is, besides the first occurrence of m. subconcava, marked by the occurrence of the cited cuneolinids, including c. sliteri, and approxi­ mates the aptian–albian chronostratigraphic boun­ dary. 3.2.5.14.“valdanchella” dercourti partial­range zone or “valdanchella” dercourti–neoiraquia convexa interval zone (velić & sokač, 1978b) boundaries: from the first occurrence of ‘v.’ dercourti to the first occurrence of n. convexa. index and important taxa: ‘v.’ dercourti, simplorbi­ tolina broennimanni, neoiraquia insolita, para­ coskinolina fleuryi, p. sunnilandensis and s. aurun­ censis. stratigraphic range: older part of the late albian. discussion: this foraminiferal assemblage has a mixed character, since it is composed of taxa of wider stratigraphic range through the early cretaceous, together with index fossils and taxa which first appeared in the albian and continued into the late cretaceous. index fossils for this zone are orbi­ tolinid species ‘v.’ dercourti, n. insolita, s. broen­ nimanni and p. fleuryi. taxa of wider stratigraphic range through several early cretaceous zones are v. scarsellai, v. laurentii, s. minuta, s. auruncensis, m. bulgarica, and p. infracretacea, which disap­ peared by the end of the albian, while p. auriger­ ica, p. heimi, s. cretacea, s. pumila, s. phoenissa, n. picardi and n. simplex continued into the late cretaceous (gušić & jelaska, 1990; velić & vlahović, 1994). dasyclad alga salpingoporella turgida is, among other microfossils, very impor­ tant for this zone, and it frequently accompanies the cited orbitolinids (velić & sokač, 1978a, 1979, 1983; velić et al., 1995; husinec et al., 2000; cvetko tešović, 2000). 3.2.5.15. neoiraquia convexa taxon­range zone or neoiraquia convexa–conicorbitolina conica interval zone boundaries: stratigraphic range of n. convexa. index and important taxa: n. convexa, ‘v.’ dercourti, ovalveolina maccagnoae, ?sellialveolina viallii, scandonea pumila, s. phoenissa and protochry­ salidina elongata. stratigraphic range: latest albian (vraconian)–earliest cenomanian. discussion: index fossils are n. convexa, ‘v.’ dercourti and p. elongata which did not survive into the cenomanian, as well as o. maccagnoae and s. vial­ lii, the stratigraphic range of which is late albian and early cenomanian. therefore, this zone would comprise the boundary between the albian and the cenomanian. sabaudia minuta ends in this zone, while all other taxa continue into the late creta­ ceous. polšak et al. (1982) also mentioned s. minuta in lower cenomanian deposits. the begin­ ning of the stratigraphic range of the nezzazatids n. gyra and n. conica occurs within this zone, and their maximum was during the cenomanian. 3.2.6. late cretaceous in spite of the numerous published papers with cited taxa and assemblages of benthic foraminifera from upper cretaceous deposits of the adcp, there are rela­ tively little data on the biostratigraphical zonation. as previously mentioned, gušić & jelaska (1990) correlated lithostratigraphic units of the island of brač with the biozonation after fleury (1980), and velić & vlahović (1994) determined five biozones in the cenomanian deposits of n istria. zones defined here (fig. 11) represent the first attempt to biostratigraphi­ cally subdivide the upper cretaceous deposits of the adcp on the basis of foraminiferal assemblages. 3.2.6.1. conicorbitolina conica/conicorbitolina cuvillieri partial–range zone or conicorbitolina conica/ conicorbitolina cuvillieri–chrysalidina gradata interval zone boundaries: from the first occurrence of c. conica and/ or c. cuvillieri to the first occurrence of c. gradata. 3� geologia croatica 60/1 2−4 9.1 c on ia ci an turoniancenomanian s an to ni an campanian maastrichtian pseudorhipidionina murgiana fig. 11 biostratigraphic subdivision of the upper cretaceous deposits of the adcp. legend: 1) conicorbitolina conica/conicorbitolina cuvillieri partial-range zone; 2–�) chrysalidina gradata superzone: 2) chrysalidina gradata partial-range zone; 3) pastrikella balcanica–conicorbitolina conica concurrent-range zone; �) vidalina radoicicae–c. gradata concurrent-range zone; �) chrysalidina gradata–pseudocyclammina sphaeroidea interval zone; 6) pseudocyclammina sphaeroidea–scandonea samnitica interval zone; 7) scandonea samnitica–dicyclina schlumbergeri interval zone; 8) dicyclina schlumbergeri–murgella lata interval zone; 9) murgella lata partial-range zone; 9.1) keramosphaerina tergestina abundance subzone; 10) calveziconus lecalvezae taxon-range zone; 11) calveziconus lecalvezae–murciella cuvillieri interval zone; 12) murciella cuvillieri and rhapydionina liburnica assemblage zone; 12.1) fleuryana adriatica taxon-range subzone. 3�velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... index and important taxa: c. conica, c. cuvillieri, c. gr. corbarica–conica, orbitolina gr. concava, o. gr. sefini–concava, ?sellialveolina viallii, ovalveolina maccagnoae, o. crassa, praealveolina simplex, p. iberica, cisalveolina lehneri, pseudocyclammina rugosa, pastrikella biplana and trocholina arabica. stratigraphic range: early cenomanian. discussion: the orbitolinids c. conica, c. cuvillieri, c. gr. corbarica–conica, o. gr. concava and o. gr. sefini–concava were determined in the assemblage, together with index forms of cenomanian alveo­ linids, o. crassa, p. simplex and p. iberica. the stratigraphic ranges of these taxa were according to schroeder & neumann (1985), undoubtedly defined as early cenomanian. 3.2.6.2–3.2.6.4. chrysalidina gradata superzone boundaries: stratigraphic range of chrysalidina gra­ data. index and important taxa: cited in descriptions of the following three zones. stratigraphic range: middle and late cenomanian. discussion: c. gradata is probably the most widespread foraminiferal species within middle and upper cenomanian deposits of the adcp. the chronostrati­ graphic value of this species has been confirmed in numerous publications in the last two decades (e.g. gušić et al., 1988; fuček et al., 1990; gušić & jelaska, 1990; velić & vlahović, 1994; husinec et al., 2000; korbar et al., 2001). therefore, within these deposits, i.e. within its stratigraphic range, one superzone, and at least three clearly differentiated zones can be defined: – chrysalidina gradata partial­range zone, – pastrikella balcanica–conicorbitolina conica con­ current­range zone, and – vidalina radoicicae–c. gradata concurrent­range zone. 3.2.6.2. chrysalidina gradata partial­range zone or chrysalidina gradata–pastrikella balcanica interval zone boundaries: from the first occurrence of c. gradata to the first occurrence of p. balcanica. index and important taxa: c. gradata, c. cuvillieri, c. conica, c. gr. corbarica–conica, o. gr. concava, o. gr. sefini–concava, p. iberica, o. crassa, c. leh­ neri, nummoloculina? regularis, pseudolituonella reicheli, pseudorhapydionina dubia, merlingina cretacea, p. biplana and peneroplis turonicus. stratigraphic range: early middle cenomanian. discussion: most of the cenomanian orbitolinids still occurred in the first part of the stratigraphic range of c. gradata together with other index fossils of the middle–late cenomanian, including n.? regu­ laris, p. turonicus and p. reicheli, continuing up to the first occurrence of p. balcanica. by analysis and correlation of the stratigraphic ranges, and compari­ son with other cenomanian foraminifera, it is pos­ sible to conclude a very precise chronostratigraphic definition for this zone in the early middle cenoma­ nian. within older middle cenomanian deposits of n istria, velić & vlahović (1994) proposed an earlier chrysalidina gradata partial­range zone and younger chrysalidina gradata and pastrikella bal­ canica assemblage zone. they divided the earlier zone into two subzones: an older, c. gradata with orbitolinids, and younger, c. gradata without orbi­ tolinids. during later investigations in other parts of the adcp, partly published in a paper by husinec et al. (2000), as well as during detailed investiga­ tions for this study, cenomanian orbitolinids were discovered in deposits of ages up to the end of the middle cenomanian in different parts of the plat­ form: it seems that their absence in some places is locally restricted. therefore, it seems that definition of three zones within the middle and late cenoma­ nian, as proposed here, would be best. 3.2.6.3. pastrikella balcanica–conicorbitolina conica concurrent-range zone (older part of the zone broeckina balcanica fleury, 1980). boundaries: from the first occurrence of p. balcanica to the last occurrence of c. conica. index and important taxa: most of the species as in the previous zone (fig. 13), accompanied by p. bal­ canica. stratigraphic range: late middle cenomanian. discussion: p. balcanica is, together with c. gradata, the most common, and widely distributed index fossil within the middle and upper cenomanian deposits of the adcp. its first occurrence represents an important biohorizon at the beginning of the younger part of middle cenomanian deposits. this provides a basis for the definition of this biozone, which is, according to its foraminiferal assemblage and stratigraphic position in the late middle cenom­ anian, equivalent to the c. gradata and p. balcanica assemblage zone of velić & vlahović (1994). husinec et al. (2000) have defined a maximum of the development (and abundance) of conicorbitoli­ na conica in the middle cenomanian limestones of the island of cres, which are stratigraphically equiv­ alent to the top part of this zone. 3.2.6.4. vidalina radoicicae–chrysalidina gradata concurrent-range zone (younger part of the p. balcanica zone after fleury, 1980; c. gradata and v. radoicicae assemblage zone or p. balcanica and n.? regularis abundance zone after velić & vlahović, 1994). boundaries: from the first occurrence of v. radoicicae to the last occurrence of c. gradata or range of the maximum abundance of p. balcanica and n.? regu­ laris. 36 geologia croatica 60/1 index and important taxa: c. gradata, v. radoici­ cae, nummoloculina? regularis, pseudolituonella reicheli, pseudorhapydionina dubia, p. laurinen­ sis, merlingina cretacea, cisalveolina fraasi, pseu­ dorhipidionina casertana, p. murgiana, peneroplis turonicus and peneroplis parvus. stratigraphic range: late cenomanian. discussion: the c. gradata, p. balcanica and v. radoi­ cicae assemblage zone was defined within the upper cenomanian carbonates of n istria by velić & vlahović (1994). they noted that this zone could also have been defined as the p. balcanica and n. regularis abundance or acme­zone, because these species had their maximum frequency within this biozone, although their stratigraphic range is wider than the late cenomanian. within the foraminiferal assemblage, cited index forms have variable strati­ graphic ranges, and only v. radoicicae has a strati­ graphic range throughout the zone. however, on the basis of the former investigation it seems that this fossil had a relatively poor distribution over the plat­ form, and so was not used to define this zone as a taxon­range zone. a similar situation occurs for the other index fossils, including c. fraasi, p. laurinen­ sis, p. casertana, p. murgiana and p. parvus. 3.2.6.5. chrysalidina gradata–pseudocyclammina sphaeroidea interval zone boundaries: from the last occurrence of c. gradata to the first occurrence of p. sphaeroidea. important taxa: the foraminiferal assemblage is sig­ nificantly reduced due to temporary drowning of the platform, so there are no index fossils. only taxa of wider stratigraphic range occurred, cited in the previous section (and shown on fig. 6), as well as planktonic foraminifera in pelagic deposits. stratigraphic range: latest cenomanian–early turo­ nian. discussion: drowning of the platform also interrupted the evolution of the platform benthic foraminifera. consequently, this zone comprises only forms of a wider stratigraphic range. however, its boundaries are clearly defined by two important biohorizons, the last occurrence of c. gradata and the first occur­ rence of p. sphaeroidea and moncharmontia apen­ ninica. 3.2.6.6. pseudocyclammina sphaeroidea–scandonea samnitica interval zone or pseudocyclammina sphaeroidea partial­range zone boundaries: from the first occurrence of p. sphaeroi­ dea to the first occurrence of s. samnitica. important taxa: p. sphaeroidea and m. apenninica. stratigraphic range: late turonian–earliest coniacian discussion: there are no index fossils; p. sphaeroidea occurs from the beginning of the zone, while m. apenninica and m. compressa appear in younger levels. 3.2.6.7. scandonea samnitica–dicyclina schlumbergeri interval zone or scandonea samnitica partial­range zone boundaries: from the first occurrence of s. samnitica to the first occurrence of d. schlumbergeri. important taxa: s. samnitica, p sphaeroidea, m. com­ pressa and m. apenninica. stratigraphic range: early coniacian. discussion: this zone has no index fossils: it contains forms determined in the previous zone as well as some without biostratigraphic significance. 3.2.6.8. dicyclina schlumbergeri–murgella lata interval zone or dicyclina schlumbergeri partial­range zone boundaries: from the first occurrence of d. schlum­ bergeri to the first occurrence of m. lata. important taxa: s. samnitica, p sphaeroidea, m. apen­ ninica, m. compressa, d. schlumbergeri, accordiel­ la conica and idalina antiqua. stratigraphic range: coniacian. discussion: this zone represents the most of conia­ cian deposits without forms of narrow stratigraphic range, but which lies between two important bio­ horizons, between the first occurrences of d. sch­ lumbergeri and m. lata, two frequent larger benthic foraminifera on the adcp. 3.2.6.9. murgella lata partial-range zone or murgella lata–calveziconus lecalvezae interval zone boundaries: from the first occurrence of m. lata to the first occurrence of c. lecalvezae. index and important taxa: murgella lata, pseudo­ rhapydionina mediterranea, keramosphaerina terg­ estina, k. ?sarda, s. samnitica, reticulinella fleuryi, r. reicheli, d. schlumbergeri, a. conica, broekinella neumannae, m. apenninica, m. compressa, pseudo­ cyclammina massiliensis, p. sphaeroidea, pseudol­ ituonella mariae, archiacina munieri, dictyopsella kiliani, dictyopselloides cuvillieri, i. antiqua and orbitoides gr. hottingeri. stratigraphic range: early santonian–early campa­ nian. discussion: deposits within this zone contain one of the richest, and biostratigraphically and palaeo­ geographically most important upper cretaceous foraminiferal assemblages. the most important species is m. lata, accompanied by almost all the forms cited in the previous two zones, together with newly occurring index forms – p. mediterranea, k. tergestina, p. massiliensis, p. mariae, r. fleuryi, r. reicheli, d. kiliani, d. cuvillieri, a. munieri, b. neu­ mannae and o. gr. hottingeri. the palaeogeographic significance of this zone is that it represents the youngest cretaceous deposits covered by eocene deposits over the major part of the adriatic carbonate platform in ne istria, s and e lika, dalmatia and herzegovina. 37velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... 3.2.6.9.1. keramosphaerina tergestina abundance subzone boundaries: stratigraphic range of the maximum abun­ dance of k. tergestina. index and important taxa: most of the taxa cited in the previous zone (fig. 11). stratigraphic range: late santonian–early campa­ nian. discussion: in the younger part of this zone the level with frequent and/or abundant occurrences of larger k. tergestina is especially important, enabling sepa­ ration of these deposits in the subzone. 3.2.6.10. calveziconus lecalvezae taxon-range zone boundaries: stratigraphic range of c. lecalvezae. index and important taxa: c. lecalvezae, most of the taxa cited in the previous zone (fig. 11) and num­ mofallotia cretacea, orbitoides tissoti, o. douvillei, o. media, p. douvillei and pseudosiderolites vidali. stratigraphic range: campanian. discussion: index fossils are c. lecalvezae and o. tis­ soti. within this zone, many of the important late santonian–campanian species disappeared: k. terge­ stina, m. lata, a. munieri, p. mariae, b. neumannae, and o. gr. hottingeri (fig. 13). most of the orbitoids continued into the next zone, and o. media occurs near the end of this zone. there are only a few areas on the adcp with con­ tinuous depositional sequences and foraminiferal assemblages which could enable detailed biostrati­ graphic zonation within these youngest cretaceous deposits. different environments existed within these spatially restricted depositional areas, repre­ senting an additional difficulty for biostratigraphic zonation and correlation. therefore this zone con­ tains foraminifera from different biotopes, e.g. o. tissoti, o. douvillei, o. media, p. douvillei and p. vidali from platform margin and slopes and r. libur­ nica, p. mediterranea, s. samnitica, p. massiliensis and p. sphaeroidea from subtidal environments. it is difficult to precisely correlate the stratigraphic ranges of taxa from both groups. gušić & jelas­ ka (1990) discussed in detail the difficulties with facies interpretation with a simultaneous occurrence of hyaline and imperforate foraminifera. this was based on the relationship between the campanian pučišća formation and the maastrichtian sumartin formation on the island of brač. each attempt to produce a more detailed biozonation in cases like this would be uncertain and speculative, and would only increase possible mistakes. therefore, the best or the least erroneous choice would be to unite taxa in assemblages within assemblage zones. 3.2.6.11. calveziconus lecalvezae–murciella cuvillieri interval zone boundaries: from the last occurrence of c. lecalvezae to the first occurrence of m. cuvillieri. important taxa: m. apenninica, m. compressa, d. sch­ lumbergeri, p. sphaeroidea, p. douvillei, p. vidali, o. douvillei, o. media and n. cretacea. stratigraphic range: latest campanian–early maas­ trichtian. discussion: deposits of this zone have been found near the platform margins and slopes of the adcp, while the major part of it was emergent. these depos­ its crop out e.g. in s croatia, on the island of brač, where gušić & jelaska (1990) determined foraminiferal assemblages with predominant orbi­ toids from detailed studied sections. there are no index fossils specific for this zone. 3.2.6.12. murciella cuvillieri and rhapydionina liburnica assemblage zone boundaries: from the first occurrence of m. cuvillieri to the last occurrence of r. liburnica. index and important taxa: murciella cuvillieri, m. renzi, rhapydionina liburnica, cuneolina ketini, fleuryana adriatica, orbitoides media, siderolites calcitrapoides, omphalocyclus macroporus and hellenocyclina beotica. stratigraphic range: maastrichtian. discussion: deposits of this zone were studied on the island of brač (gušić & jelaska, 1990), where in the studied sections murciella gr. cuvillieri occurs before rhapydionina liburnica. an orbitoidid and siderolitid assemblage was determined in slope facies of the platform margins, and also locally in the area of intraplatform troughs (e.g. velić, 1973; velić et al., 1982; gušić & jelaska, 1990; veseli, 1999; dragičević & velić, 2002). 3.2.6.12.1. fleuryana adriatica taxon­range subzone boundaries: stratigraphic range of f. adriatica. index and important taxa: f. adriatica, r. liburnica, d. schlumbergeri and laffitteina? mengaudi. stratigraphic range: late maastrichtian. discussion: deposits of this subzone were observed in s croatia (island of brač), in the central adriatic in the kate–1 well, as well as in the nw part of the platform in sw slovenia, and in the vicinity of tri­ este in italy (de castro et al., 1994). within the deposits with abundant f. adriatica, drobne et al. (1989) discovered two very important species of larger foraminifera, r. liburnica and d. schlumber­ geri, while jurkovšek et al. (1996) only cited r. liburnica. at the type locality of f. adriatica within the upper maastrichtian deposits on the island of brač, de castro et al. (1994) mentioned only laffitteina sp. and bolivinopsis sp. r. liburnica and laffitteina mengaudi were discovered earlier in the same deposits (gušić & jelaska, 1990). 38 geologia croatica 60/1 4. palaeobiogeography of mesozoic benthic foraminifera of the karst dinarides the limited platform area and incomplete micropalae­ ontological investigation are two important factors that hinder construction of a complete and detailed pal­ aeobiogeography of benthic foraminifera on the adcp. taking into account that the adcp was about 700 km long and probably 300–400 km wide, it is clear that it represented a relatively small part of large shallow­ marine areas of tethys. within the continuous dynamic succession of events, the adriatic carbonate platform evolved from a position in the southern, marginal area of tethys during the early jurassic, through an indi­ vidualized oceanic platform in the central tethyan area with a probable connection to the albanian and hellenic platforms, to its disintegration in the northern tethyan area during the late cretaceous. its palaeogeographic position controlled climatic changes, sedimentary envi­ ronments and ecological conditions, which directed the palaeobiogeography of the foraminiferal taxa, groups or complete assemblages. given the aforementioned lim­ ited extent and moderate knowledge, the distribution of mostly larger foraminifera, especially index forms, will be discussed and presented here. this review will cover mesozoic assemblages, becoming more detailed after the early and middle triassic, through the late triassic and early jurassic (when the adcp became separated from the apulian and apenninic platforms), to the end of cretaceous. the process of platform separation prob­ ably started in the late triassic, and was completed during the pliensbachian and toarcian. since then, the adcp represented a specific palaeogeographic entity until its final disintegration by the end of cretaceous. 4.1. triassic among early triassic foraminifera, meandrospira pusila was the most widespread and the most frequent, together with abundant, though often poorly studied specimens of other smaller foraminifera, including glomospira sygmoidalis, glomospirella triphonensis, ammodiscus parapriscus, arenovidalina sp., etc. these forms were discovered in all areas with outcrops of lower triassic rocks, e.g. sw slovenia, around kar­ lovac and slunj, in velebit mt., lika, and dalmatia in croatia, sw bosnia and herzegovina and s montene­ gro. middle triassic index forms were only observed within anisian deposits. these aresmaller foraminif­ era meandrospira dinarica, pilammina densa and pil­ amminella semiplana. these forms were widespread throughout the dinarides, including areas that repre­ sented the basement of the future adcp. as in other periadriatic regions (e.g. the alps and the carpathians), there are no index foraminifera for the ladinian in the dinarides, since all forms (mostly the smaller foraminif­ era) had wider stratigraphic ranges. within middle tri­ assic deposits grgasović (2003) mentioned the beginning of the stratigraphic ranges of some species of involutinids – aulotortus sinuosus from the late ani­ sian and a. praegaschei from the late ladinian. during a considerable part of the late triassic, i.e. during the carnian and early norian, the major part of the investigated area was emergent. therefore, depos­ its containing shallow­marine benthos occurred only within marginal areas, e.g. around karlovac speci­ mens of lamelliconus – l. multispirus and l. procerus occured (grgasović, 1997), as well as l. procerus in the area of komiža on the island of vis (belak et al., 2005). assemblages within upper norian deposits contain the following involutinids: aulotortus friedli, a. tenuis, a. sinuosus, a. praegaschei and a. tumidus. these were accompanied in the rhaetian by triasina hantkeni and auloconus permodiscoides. localities in the croatian part of the karst dinarides where these are observed include the area of karlovac (bukovac et al., 1974, 1984; grgasović, 1997, 2003), the gorski kotar (savić & dozet, 1985), ogulin (velić et al., 1982), vicinity of slunj (korolija et al., 1981), s velebit mt. and lika, svilaja mt. (bucković et al., 2003) and the vicinity of ston (raić & papeš, 1982). in slovenia they have been found in the vicinity of tolmin (buser, 1986). in bosnia and herzegovina and mon­ tenegro the aforementioned assemblages were found along ne and se margin of the adcp (mojičević et al., 1977, 1979; marinković & đorđević, 1981; vrhovčić & mojičević, 1983; vujnović, 1981; papeš, 1975; sofilj et al., 1980; mirković, 1980; vujisić, 1975; živaljević et al., 1971, 1989; kalezić et al., 1973; đokić et al., 1976; mirković et al., 1978). therefore, it may be con­ cluded that this assemblage was very widespread in the karst dinarides deposits in the immediate basement of the adriatic carbonate platform. 4.2. jurassic there are no specific issues with the palaeobiogeo­ graphy of the early jurassic foraminifera (fig. 12). assemblages of the early jurassic lituolids are known from all areas where lower and middle lower jurassic deposits crop out, so it may be concluded that these foraminifera were spread throughout the area of the karst dinarides. the most widespread were renowned assemblages of early jurassic lituolids with mesoen­ dothyra sp. and orbitopsella praecursor, o. primaeva, lituosepta recoarensis, haurania deserta and amijiella amiji. representatives of the biokovinids in the karst dinarides (gušić, 1977) were restricted to local occur­ rences, e.g. bosniella oenensis in w bosnia and the vicinity of dubrovnik, biokovina gradacensis in biok­ ovo mt. and dubrovnik area. pseudocyclammina lias­ sica was found at several localities in croatia (w gor­ ski kotar, velika kapela, velebit, biokovo and vicinity of dubrovnik), but it may be proposed that it has been 39velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... more widespread, since sampling of this level was very restricted. distribution of lituolipora termieri, shows a similar pattern as it is common in the middle part of the lower jurassic deposits of velika kapela mt. (w croatia). toarcian and early aalenian deposits of the karst dinarides contain no larger foraminifera, as a conse­ quence of unfavourable ecological conditions, since the very shallow marginal parts of the platform were cov­ ered by ooid–intraclastic bars, and the inner parts had lagoonal environments with low sedimentation rates of fine­grained deposits. involutina liassica seems restricted to the ne marginal areas of the platform towards the slovenian and bosnian basin, in karlo­ vac area (radoičić, 1966; gušić & babić, 1970; dragičević & velić, 2002), northern herzegovina (sofilj et al., 1980), montenegro (radoičić, 1966; mirković, 1980; vujisić, 1975; živaljević et al., 1989), and on the slopes towards the budva–cukali trough (mirković et al., 1978; antonijević et al., 1973). the palaeobiogeography of the middle jurassic foraminifera is much more interesting. their occurrence and frequency was controlled by palaeogeography. more variable and rich assemblages were found in the marginal, mostly peritidal parts of the platform, less in the slightly deeper subtidal inner platform environments (fig. 13). mesoendothyra croatica was the most widespread middle jurassic foraminifera, with a stratigraphic range from the late toarcian to the early bathonian. it spread all over the adcp, and in places is very abundant (e.g. in the vicinity of dubrovnik). for years this foraminif­ era was the only index fossil in middle jurassic rocks older than the bathonian, especially in the central and western parts of the platform. gutnicella cayeuxi had been described (anić, 1962; radoičić, 1966) prior to the description of m. croatica (gušić, 1969a). this foraminifera is much rarer than m. croatica, being com­ mon only in the se part of the platform (s croatia and montenegro; fig. 13). aalenian–bajocian foraminifera, including timidonella sarda, spiraloconulus gigan­ teus and s. perconigi are new discoveries on the adcp. they were observed in two areas: the nw part of the platform, se of ljubljana (krka, slovenia), and in the se part in biokovo mt., and the vicinity of dubrovnik fig. 12 distribution of important foraminiferal taxa within the lower jurassic deposits of the adcp. �0 geologia croatica 60/1 in croatia (fig. 13), together with g. cayeuxi and m. croatica. isolated occurrences of g. cayeuxi were also observed in gorski kotar and sw of karlovac in croatia, the vicinity of jajce in bosnia, as well as in montenegro – in the vicinity of nikšić and the coastal area. within middle jurassic deposits, haurania deser­ ta and amijiella amiji occur in places. these were once considered to be index fossils of the middle part of the early jurassic. pseudodictyopsella jurassica and mar­ zoella ficcarellii are first documented here for the adcp in the area of the biokovo mt. this represents the sec­ ond occurrence of these forms in the world, after initial discovery of p. jurassica in oman (septfontaine & de matos, 1998), and m. ficcarellii in italy (chi­ occhini & mancinelli, 2000). p. maynci has previously only been observed at the aalenian–bajo­ cian transition on the adcp, while in other parts of both major neotethyan provinces it was described as being of bathonian and callovian age (bassoullet et al., l985; bassoullet, 1997). orbitammina elliptica occurs in an assemblage with other bathonian species, previously unknown on the adcp, including alzonella cuvillieri, satorina mesojurassica and pseudoeggerella elongata in istria and velebit mt. (fig. 13). these occur together with the somewhat more frequent kilianina blancheti and pfenderella arabica. however, within this assemblage the most important and most widespread forms on the adcp are those that are also very frequent in the medi­ terranean area – paleopfenderina salernitana, p. tro­ choidea and satorina apuliensis. forms having wider stratigraphic ranges through either the entire or a larger part of the middle jurassic frequently occur. these include redmondoides lugeoni, siphovalvulina variabilis, pfenderella arabica and pro­ topeneroplis striata, and praekurnubia crusei from the bathonian, and mohlerina basiliensis and kurnubia jurassica from the callovian. discovery of species previously unknown on the adcp are especially important for the palaeobiogeo­ graphy of the middle jurassic foraminifera. of these, spiraloconulus giganteus and orbitammina elliptica, are particularly interesting, as they had been consid­ ered as forms inhabitating the western mediterranean palaeobiogeographic province (w alps, jura mt., n sardinia, aquitaine and paris basins), as well as some fig. 13 distribution of important foraminiferal taxa within the middle jurassic deposits of the adcp. �1velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... eastern provinces (caucasus and turkmenistan). these western and eastern provinces represented parts of the northern neotethyan margin (bassoullet et al., l985). occurrences of s. giganteus (fig. 13) in krka area (slovenia), biokovo mt. and dubrovnik, together with observations of o. elliptica (fig. 13) in istria and velebit mt. extend their distribution to the southern marginal areas of neotethys, indicating the necessary reinterpretation of traditional middle jurassic palaeobio­ geography. k. blancheti, s. mesojurassica and p. elon­ gata also occur in smaller areas of the western part of the platform, between w istria and s velebit mt., while paravalvulina complicata was found for the first time on the adcp in the vicinity of dubrovnik, and later in biokovo mt. and vicinity of karlovac. the most widespread late jurassic foraminif­ era was kurnubia palastiniensis, occurring in all parts of the platform. two other forms of kurnubia were frequently cited under this name: k. wellingsi and k. jurassica. there is no consensus among micropalaeon­ tologists as to the validity of these citations. all three species are widespread on the adcp. in addition to kur­ nubias, the most frequent species were mohlerina basil­ iensis, nautiloculina oolithica, praekurnubia crusei and protopeneroplis striata, while labyrinthina mirabilis and parurgonina caelinensis are somewhat rarer (fig. 14). trocholina species are frequent, especially t. alpi­ na, with a stratigraphic range from the bajocian to the late hauterivian, and t. elongata from the oxfordian. they were the most abundant in the oxfordian tem­ pestites and carbonate beach sands of w istria, gorski kotar and velebit mt., in an assemblage with chablai­ sia chablaisensis. in the central parts of the platform ch. chablaisensis had only been reported at one locality in biokovo mt. (but was probably of bathonian/callo­ vian age), and in the oxfordian of lastovo island. tro­ cholina gigantea was only found in the oxfordian of istria and gorski kotar (w croatia). alveosepta jaccardi and conicokurnubia orbito­ liniformis were discovered in the kimmeridgian of the velika kapela, velebit and biokovo mts. in croatia, so, at this point they can be considered as index fos­ sils of that stage in the area of the adcp. three addi­ tional infrequent foraminifera, previously unknown in the adcp area, are kilianina? rahonensis from the late fig. 1�. distribution of important foraminiferal taxa within the upper jurassic deposits of the adcp. �2 geologia croatica 60/1 kimmeridgian and tithonian of w croatia, and the late tithonian anchispirocyclina lusitanica and/or a. neumannae, found only in s croatia (fig. 14). this list could be completed by everticyclammina virguliana, usually found within upper jurassic peri­reefal deposits of marginal parts of the platform. 4.3. cretaceous the adriatic carbonate platform and neighbouring more or less isolated central mediterranean carbonate platforms (e.g. apenninic, apulian, gavrovo–tripolit­ za, etc.) were all located within southern tethyan bio­ provinces. they were characterized by the reduced occurrence of larger foraminifera from the berriasian to the late barremian. in contrast, in the western mediter­ ranean, carbonate platforms belonging to the northern tethyan bioprovinces (cantabria, pyreneans, sardinia, vercors, chartreuse, jura mt., etc.) larger foraminifera were present in the berriasian, valanginian and haute­ rivian. species include keramosphaera allobrogensis steinhauser, brönnimann & koehn-zani­ netti, eclusia moutyi septfontaine, e. decastroi cherchi & schroeder and valdanchella miliani (schroeder), as well as other orbitolinids which were completely missing in the contemporaneous deposits in the adcp area. in the neocomian and early barremian deposits of the adcp foraminiferal assemblage including trocholi­ na gr. alpina–elongata, charentia cuvillieri, mayncina bulgarica and praechrysalidina infracretacea is char­ acterized by a modest stratigraphic value, and the first index fossils occur in the orbitolinid assemblages of the late barremian. however, many small foraminif­ era represent index fossils, e.g. for the valanginian ver­ corsella camposaurii, v. tenuis, montsalevia salevensis, haplophragmoides joukowskyi, or late hauterivian campanellula capuensis. all these taxa were distributed throughout the adcp. protopeneroplis ultragranulata is the index spe­ cies of transitional tithonian–berriasian and berria­ sian deposits, and was previously only known from the coastal part of southern croatia (biokovo mt., vicinity of dubrovnik). representatives of the genus trocholi­ na, for example, t. gr. alpina–elongata, as well as t. sagittaria, t. delphinensis, and probably also t. molesta occur throughout the platform area. in the barremian and early aptian of the western parts of the platform, t. lenticularis was locally found, and mostly undeter­ minable small involutinids are also frequent. the entire platform area is also characterized by the occurrence of representatives of vercorsella, sabaudia and novalesia with v. camposaurii, v. tenuis (the index fossil of the valanginian and early hauterivian), v. scarsellai, v. laurentii, v. arenata and v. wintereri, n. cornucopia, n. distorta, n. producta and s. minuta. all of these have a wider stratigraphic range through the early cretaceous. s. briacensis is always found together with palorbitolinids (and is the index fossil of the early aptian), s. auruncensis, s. capitata and s. dinapolii range from the late aptian–early albian. during the late barremian an orbitolinid assem­ blage occurred on the adcp. rectodictyoconus gigan­ teus is the oldest orbitolinid genera on the adcp, pre­ viously known only in the vicinity of jajce and banja luka near the northern margin of the platform. comparison with the palaeogeography of orbi­ tolinids found on perimediterranean platforms indicates differences between the adcp and western mediterra­ nean platforms. orbitolinid assemblages in the western mediterranean, i.e. northern tethyan provinces, devel­ oped in the earliest cretaceous. examples include the valanginian of the pyrenees (valdanchella, paracoski­ nolina etc., according to peybernes, 1976), haute­ rivian of se france (e.g. evolutionary lines praedicty­ orbitolina–dictyorbitolina and valserina–palorbitolina (according to clavel et al., 1995 and arnaud et al., 1998) and the barremian of the aforementioned are­ as (eopalorbitolina–palorbitolina after schroeder et al., 2002 or paracoskinolina, urgonina, alpillina, cribellopsis and diverse species of genus orbitolinop­ sis according to, e.g. arnaud et al., 1998). a rich and explosive development of orbitolinids on the adriatic carbonate platform started in the latest barremian/earliest aptian, when varied assemblages of taxa especially abundant in the northern tethyan provinces (like palorbitolinids and praeorbitolinids, as well as mesorbitolinids in the late aptian and albian), became distributed throughout the platform. in contrast to r. giganteus, only discovered in the central part of the ne adcp margin in upper barremian deposits (fig. 16), palorbitolina lenticularis was found all over the adcp. some authors (velić & sokač, 1978a) indi­ cate that this species occurred on the adcp at the very end of the barremian, i.e. somewhat later than in the western mediterranean, where it occurred in the middle barremian (e.g. schroeder, 1964c; schroeder et al., 1974; peybernes, 1976; arnaud­van­ neau, 1980; jaffrezo, 1980; clavel et al., 1995; arnaud et al., 1998). on the apenninic carbonate platform (which should have been, according to the palaeogeographic interpretations, located between the western mediterranean platforms and the adcp dur­ ing the aptian), deposits with palorbitolinids are either of upper barremian–lower aptian age (chiocchini et al., 1994) or lower aptian age (cherchi et al., 1978). the palaeobiogeography of early aptian foramini­ fera on the adcp was very controlled by the palaeoen­ vironments. generally, in this area, this period was characterized by sea­level rise and pelagic influences, represented by common findings of hedbergella sp., saccocoma sp. etc. (velić & sokač, 1978a). these forms only occur in very restricted subtidal facies and lagoons together with choffatella decipiens, in the cen­ tral and western parts of the platform. dominant early aptian foraminifera are orbitoli­ �3velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... nids from the evolutionary line praeorbitolina cormyi – p. wienandsi – mesorbitolina lotzei. they occur in the w, central and se parts of the platform (velić & sokač, 1978b; velić et al., 1979; husinec et al., 2000) (fig. 15). accompanying forms are early aptian index fossils found throughout the platform area: voloshinoides murgensis (the most frequent), sabau­ dia briacensis, derventina filipescui, pseudolituonella conica, neotrocholina aptiensis and n. friburgensis, as well as rare pfenderina globosa. earliest representa­ tives of the archalveolina genus (velić & sokač, 1978a), pseudonummoloculina aurigerica, as well as all the aforementioned species of sabaudia, vercorsella, novalesia, nautiloculina, etc. occur. in the late aptian, orbitolinid evolutionary trends continued with mesorbitolina parva and mesorbitolina texana, found in all parts of the platform. these forms were accompanied by archalveolina reicheli, locally very abundant haplophragmoides globosus (or troc­ hamminoides coronus according to chiocchini et al., 1994), and, close to the end of aptian, orbitolinop­ sis aquitanica. all these forms were, previously only known from the coastal, adriatic part of croatia. mesorbitolinid assemblages continued into the ear­ ly albian. they were widespread, and known from all parts of the platform. therefore, with the early aptian palorbitolinids, they represent not only the most fre­ quent orbitolinids, but also some of the most extensive foraminifera on the entire adcp. in addition, in the late aptian, m. parva and m. texana occur, continuing into the early albian, where they are accompanied by mes­ orbitolina subconcava and mesorbitolina pervia. in addition to the early albian mesorbitolinids, specifically undeterminable forms of the genera orbito­ linopsis and paracoskinolina, as well as other, previous­ ly cited species of vercorsella, sabaudia, novalesia etc. were also widespread throughout the platform. how­ ever, the predominant species in foraminiferal assem­ blages of the youngermost lower cretaceous deposits were cuneolina pavonia, c. parva, pseudonummolocu­ lina heimi and nezzazatinella picardi, with stratigraphic ranges through the entire albian and a larger part of the late cretaceous. in the late albian orbitolinid assemblages with ‘valdanchella dercourti’, simplorbitolina broenni­ manni, neoiraquia insolita, paracoskinolina fleuryi, fig. 1� distribution of orbitolinids within the cretaceous deposits of the adcp. �� geologia croatica 60/1 and paracoskinolina sunnilandensis were frequent. among other rare foraminifera were scandonea phoe­ nissa and s. pumila (e.g. at biokovo mt. and the island of korčula). for the very end of the albian, vraconian or the base of cenomanian, occurrences of neoiraquia convexa (in the vicinity of dubrovnik and biokovo mt.) and protochrysalidina elongata (island of cres), as well as the more frequent ovalveolina maccagnoae are typi­ cal, though relatively rarely observed. during the cenomanian, there was a successive occurrence of alveolinids from ovalveolina maccag­ noae and ?sellialveolina viallii, through o. crassa, cis­ alveolina lehneri and praealvelina iberica in the early cenomanian, p. simplex in the middle, to cisalveo­ lina fraasi in the late cenomanian. these forms were found, although not frequently, in different parts of the adcp (fig. 16). the situation with the orbitolinids orbitolina gr. concava, conicorbitolina cuvillieri, c. conica, c. gr. corbarica–conica and orbitolina gr. sefi­ ni–concava was similar. these however, were extinct before the late cenomanian, but were widespread all over the platform (fig. 15). pastrikella biplana occurs in younger lower cenomanian beds and in older mid­ dle cenomanian deposits, where it is accompanied by p. balcanica and other middle cenomanian species. a group of index fossils of the middle and late ceno­ manian, comprising chrysalidina gradata, nummolo­ culina? regularis, pseudolituonella reicheli, pastrikella balcanica and pseudorhapydionina dubia, was very abundant in all parts of the platform (fig. 17), as well as other taxa of a wider stratigraphic range cited within the cenomanian assemblages (cuneolinas, nezzaza­ tids, pseudonumoloculinas, soritids, peneroplids). the late cenomanian pseudorhapydionina laurinensis and pseudorhipidionina casertana (polšak et al., 1982; velić & vlahović, 1994) (fig. 17), found in istria, lika, and dalmatia are rare. the early turonian was characterised by restricted foraminiferal assemblages due to platform drowning, so in a palaeobiogeographic sense it is not very interesting. during the late turonian, the entire platform (except for minor parts emergent since at least the late ceno­ manian), was again covered by shallow­marine envi­ ronments with assemblages of cuneolinas, nezzazatids, miliolids and other groups of foraminifera known since the albian and through the cenomanian. new forms fig. 16 distribution of alveolinids within the cretaceous deposits of the adcp. ��velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... which were widespread include moncharmontia apen­ ninica and pseudocyclammina sphaeroidea. cuneolina compressa was only found in the deep off­shore well near the island of palagruža. the composition of coniacian and early santonian assemblages was very similar to those from the late turonian, with the exception of newly occurring forms: scandonea samnitica, dicyclina schlumbergeri and moncharmontia compressa. important changes took place in the late santonian with the occurrence of new species of larger foraminifera – murgella lata, pseudor­ hapydionina mediterranea, idalina antiqua, keramos­ phaerina tergestina and pseudocyclammina massilien­ sis, as well as several species of smaller foraminifera – accordiella conica, murgeina apula, reticulinella fleuryi, dictyopsella kiliani, dictyopselloides cuvil­ lieri, spirolina cretacea, minouxia lobata, pseudol­ ituonella marie, rotorbinella scarsellai and stensiöina surrentina. all these forms were widespread over the adcp (fig. 18). raadshovenia salentina occurs in the santonian deposits of the nw part of the platform (s istria – polšak et al., 1982, and in the area of trieste karst – venturini, 2005), while broekinella neu­ mannae, nummofallotia cretacea, archiacina munieri and abrardia mosae were discovered in central bosnia (near jajce). along the platform slopes, as well as in the deeper parts of the inner platform, the previously men­ tioned forms were accompanied by the orbitoid species orbitoides gr. hottingeri. late santonian species also continued into the early campanian, when they were accompanied by new ones. calveziconus lecalvezae and reticulinella reicheli were found over the major part of the platform. however, they are most abundant along the adriatic coast and on the islands. along the platform margins and on the slopes or in deeper areas within the inner parts of the platform, the aforementioned assemblage was accom­ panied by praesiderolites douvillei, orbitoides douvil­ lei, o. tissoti, o. media and pseudosiderolites vidali (gušić & jelaska, 1990; fig. 18). during the maastrichtian margins, slopes and inner platform deeper areas were inhabitated by abun­ dant orbitoides media, siderolites calcitrapoides and omphalocyclus macroporus. murciella cuvillieri, m. renzi, fleuryana adriatica and laffitteina mengaudi occur on the island of brač (gušić & jelaska, fig. 17 distribution of several index and the more important foraminiferal species within the older upper cretaceous deposits (cenomanian–lower santonian) of the adcp. �6 geologia croatica 60/1 1990; de castro et al., 1994) and vicinity of makar­ ska. rhapydionina liburnica was found in areas contain­ ing maastrichtian deposits across the adcp, accompa­ nied by species with wider stratigraphic ranges through the late cretaceous, like c. pavonia, n. picardi, d. sch­ lumbergeri, m. apula, m. apenninica, a. conica and r. scarsellai. 4.4. correlation this palaeogeographic data on the adcp can be corre­ lated with data from other periadriatic carbonate plat­ forms, as well as with previous knowledge on palaeobio­ geographic provinces in neotethys during the jurassic and the cretaceous. results of these comparisons show important similarities, but also certain specificities of the adcp, which will not change the general concept of the position of the adcp in the tethyan realm during the younger mesozoic. the composition of foraminiferal assemblages definitely indicates the location of the adcp within the southern marginal part of this palaeoocean during the early and middle jurassic (bassoullet et al., l985). this can be shown by comparison of the strati­ graphic ranges of foraminifera and biozones within lower jurassic deposits of the high atlas in morocco and velebit mt. in croatia (septfontaine, 1984; tišljar et al., 1991; septfontaine et al., 1991), which are almost identical. the other perimediterranean platforms in italy, greece and turkey also belonged to south­tethyan bioprovince during the early and mid­ dle jurassic. a significant new result is the co­occurrence of orbitammina elliptica and satorina apuliensis in the bathonian deposits of istria and velebit. namely, these two forms are typical for two major neotethyan provinces, o. elliptica for the northern province, and s. apuliensis for the southern one (bassoullet et al., l985). the discovery of o. elliptica within the foraminiferal assemblage of the southern neotethyan province (velić, 2005), as well as the very serious indications of its presence in the bathonian deposits of the apenninic carbonate platform (luperto­sinni, 1968, pl./fig.: 7/1, 8/3, 9/2,3, 10/2, 11, 12), indicate that its area of distribution included the northernmost parts − fig. 18 distribution of several index and the more important foraminiferal species within the younger upper cretaceous deposits (upper santonian–upper maastrichtian) of the adcp. �7velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... of the southern neotethyan bioprovince during the bathonian. during the late cretaceous both provinces had more or less similar foraminiferal assemblages. abundant occurrences of chablaisia chablaisensis in the oxfordian of the adcp, but only in its nw part are interesting, because s of velebit mt. it has only been found at one locality in the bathonian of biokovo mt. (velić, 2005) and the island of lastovo. present data also indicate the location of the adcp within southern neotethys during the late jurassic. from the beginning of the cretaceous to the late barremian, shallow­marine environments of the north­ ern neotethyan bioprovince were gradually inhabitated by orbitolinids and other larger foraminifera (genera valdanchella, praedictyorbitolina, dictyorbitolina, valserina, eygallerina, eopalorbitolina, montseciella, eclusia, keramosphaera, pfenderina etc. – see e.g. bassoullet et al., l985; clavel et al., 1995; schroeder et al., 2002). contemporaneous depos­ its of the adcp contain no foraminifera. this indicates that at that time, the adcp was still a part of the south­ ern bioprovince, and that there was still no connection between the two major neotethyan bioprovinces. in contrast, assemblages of small foraminifera found on the adcp containing index forms for the valanginian and early hauterivian, including montsalevia salev­ ensis, haplophragmoides joukowskyi, meandrospira favrei, vercorsella tenuis and v. camposaurii, are also known from the areas along the northern neotethyan margin (where the first three cited species were origi­ nally described by charollais et al., 1966). in the late barremian and early aptian, orbitolinid assemblages rapidly spread over the southern neotethy­ an bioprovince, led by palorbitolina lenticularis, which was accompanied by praeorbitolinids – praeorbitoli­ na cormyi and p. wienandsi, as well as mesorbitolina lotzei during the early aptian. therefore, since the late barremian through the aptian, albian and early ceno­ manian, biofacies and biotopes of the larger foraminif­ era on the adcp gradually became more and more simi­ lar to those from the northern neotethyan bioprovince. bassoullet et al. (1985) acknowledged that dur­ ing the late aptian and albian it was still possible to clearly differentiate two bioprovinces within neotethys: a northern one with simplorbitolina manasi and neor­ bitolinopsis conulus, and a southern one with archaeal­ veolina and simplorbitolina ?brönnimanni. during the cenomanian, composition of orbi­ tolinid and alveolinid assemblages on the adcp (e.g. velić & vlahović, 1994; husinec et al., 2000; tišljar et al., 2002) was similar, but not identical, to contemporaneous assemblages in sw europe, i.e. areas belonging to the northern neotethyan province (e.g. schroeder, 1962, 1964a, 1975; bilotte, 1985; castro et al., 2001). in the area of the adcp, there are presently no known occurrences of mesorbi­ tolina aperta (erman) and orbitolina durandelgai schroeder among the orbitolinids, while among the alveolinids praealveolina cretacea (d’archiac), p. brevis reichel, ovalveolina ovum (d’orbigny) and pseudedomia drorimensis reiss, hamaoui & ecker are also absent. however, it cannot be affirmed that the adcp was still part of the southern neotethys bioprovince during the cenomanian, in spite of the sig­ nificant similarity of foraminiferal assemblages. for this province, typical near east species of larger foraminif­ era, including cycledomia iranica henson, taberina bingistani henson, p. drorimensis and thomasinella punica schlumberger (e.g. saint­marc, 1974, 1977; hamaoui, 1979) have never been found on the adcp. on the basis of the presented data, it may be concluded that during the cenomanian and the turoni­ an, the adcp was probably biogeographically isolated, i.e. that it was not part of either of the two major bio­ geographical provinces. this is indicated by the compo­ sition of the foraminiferal assemblage, which is similar to assemblages of both bioprovinces, but lacking forms characteristic of either. a similar view was proposed by fleury et al. (1985) for the periadriatic–aegean provinces during the late cretaceous, i.e. the adriatic carbonate platform, south apenninic platforms (most likely apulian and apenninic), hellenic platforms (gavrovo–tripolitza) and tauridic platforms (probably menderes). a late cenomanian–early turonian sea­level rise caused temporary drowning of the adcp (gušić & jelaska, 1990, 1993; jenkyns, 1991; jelaska et al., 1994; tišljar et al., 2002; vlahović et al., 2003, 2005), resulting in the temporary disappearance of shallow­marine environments favourable for biotopes of benthic foraminifera. they were later re­established due to shallowing in the late turonian, and lasted until the end of the cretaceous in parts of the platform cov­ ered by the sea. on the basis of foraminiferal assemblage composi­ tion in upper cretaceous deposits of western neotethys (upper turonian to maastrichtian), two bioprovinces can be clearly distinguished: central mediterranean, composed of the periadriatic carbonate platforms – adriatic, apenninic, apulian and gavrovo–tripolitza, and western mediterranean, comprising carbonate plat­ forms and shallow­marine areas of the present pyrenees, aquitaine, provence and sardinia. within foraminiferal assemblages of the central mediterranean bioprovince, on the adcp and neighbouring platforms (e.g. luper­ to­sinni, 1976; luperto-sinni & ricchetti, 1978; fleury, 1980; fleury et al., 1985; gušić & jelaska, 1990; chiocchini et al., 1994; cvetko tešović et al., 2001, and section 2 of this paper), there are no presently known occurrences of taxa typi­ cal for the western mediterranean bioprovince. such absent species include orbitolinopsis senonicus gen­ drot, peneroplis giganteus gendrot, lacazina elongata schlumberger, l. compressa munier­ chalmas, pseudolacazina cantabrica hottinger, drobne & caus, ilerdorbis decussatus hotting­ er & caus, broeckina dufrenoyi (d’archiac), �8 geologia croatica 60/1 cyclopsinella steinmanni (munier­chalmas), paleodictyoconus senonicus moullade & vial­ lard, abrardia catalunica bilotte, lamarmorella sarda cherchi & schroeder, periloculina zit­ teli munier-chalmas & schlumberger, etc. (gendrot, 1968, cherchi & schroeder, 1977; bilotte, 1985; hottinger et al., 1989). likewise, species typical for the central mediterranean bioprov­ ince, e.g. pseudorhapydionina mediterranea, murgella lata, keramosphaerina tergestina, murciella cuvillieri, m. renzi, rhapydionina liburnica and fleuryana adri­ atica, have never been observed in the western medi­ terranean bioprovince. therefore, it is clear that these two provinces were, according to the larger foraminif­ era, ‘isolated’ from each other. each had their typical species and assemblages, in places with even endemic characteristics (e.g. catalonian subprovince, after hot­ tinger et al., 1989). the palaeogeographic position of these provinces was from the turonian to the end of cretaceous in central neotethys, because both prov­ inces were placed between 23° and 35° n of equator after dercourt et al. (2000). during this period, the gondwanian coast of neotethys (from ethiopia/erithrea to morocco), was placed between 5° s and 18° n in the cenomanian, and from the equator to the 20° n in the maastrichtian. the european coastline was more stable, and during the late cretaceous its position was between 35° and 45° n (after dercourt et al., 2000). the position of the adcp, as the northernmost periadriatic platform in the central mediterranean bioprovince and in the late cretaceous neotethys, was between 23° and 30° n. in such a palaeogeographic constellation, when neotethys was at its widest and most complex, includ­ ing the beginning of its closure, it was characterized by the occurrence of more biogeographical provinces than at any other time. therefore, it may be concluded that in the late cretaceous, the area of the adriatic carbonate platform represented part of the central mediterranean bioprovince in the central neotethyan area. 5. review of the results the most important results of the investigation pre­ sented in this paper can be summarised in the following conclusions: – this is the first paper synthesizing and summarizing the results of mesozoic benthic foraminiferal study in the karst dinarides undertaken by the author during almost 50 years of research, – numerous new results regarding foraminiferal assem­ blages were achieved, including discovery of many taxa previously unknown in the karst dinarides, – a chronostratigraphic position is provided for forami­ niferal assemblages, – a completely new biostratigraphic zonation was pro­ duced, respecting the results of previous investiga­ tions, – for the first time the palaeobiogeography of larger foraminifera of the adcp is proposed, which is espe­ cially important for regional mediterranean correla­ tion, in which the adcp was previously inadequately represented or was completely excluded. the chronostratigraphic succession comprises foraminiferal assemblages from the early triassic to the end of the cretaceous. previous knowledge on the assemblages within lower and middle triassic depos­ its of the adriatic carbonate platform indicate a prob­ ably rich assemblage of genera and species, but reliable data could only be provided after detailed investigations which have not yet been performed. at this moment it can be stated that smaller foraminifera prevailed within these deposits, mostly ammodiscids and endothyrids. index forms are: cyclogyra mahayeri, ammodiscus paraprisca, meandrospira pusila, glomospira sygmoi­ dalis and glomospirella triphonensis for the scythian, and meandrospira dinarica, pilammina densa and pil­ amminella semiplana for the anisian. within ladinian deposits there are no index species of foraminifera, but the beginning of the stratigraphic ranges of some spe­ cies of aulotortus (a. praegaschei and a. sinuosus) can be presumed, as stated by grgasović (2003). the maximum abundance of these was in the norian and rhaetian. an assemblage of involutinids, with aulo­ tortus friedli, a. praegashei, a. sinuosus, a. tenuis, a. tumidus, was generally predominant in upper triassic deposits, and aulotortus pokornyi, trocholina crassa and t. acuta in the norian and rhaetian. besides the cited species, discovery of the index forms lamelli­ conus multispirus and l. procerus in carnian, turrispi­ rillina minima in the norian, and triasina hantkeni in the rhaetian are very important. within the jurassic deposits, lituolid foraminifera predominate, which were not equally distributed in time. during the early jurassic, mesoendothyrids were predominant with index forms including mesoendothyra sp., lituosepta recoarensis, orbitopsella primaeva and paleomayncina termieri in the sinemurian, mesoen­ dothyra sp., l. recoarensis, o. primaeva, o. praecursor, p. termieri, planisepta compressa, lituolipora polymor­ pha, biokovina gradacensi and bosniella oenensis in the early pliensbachian (carixian), and o. praecursor, o. ?dubari, pseudocyclammina liassica, p. termieri, p. compressa, b. gradacensis and b. oenensis in the late pliensbachian (domerian). as a consequence of unfa­ vourable palaeoecological conditions during the toar­ cian, a significant decline took place in the foraminif­ eral assemblage, and there were no index forms. mid­ dle jurassic deposits contain the richest foraminiferal assemblages with numerous taxa, including well known index species – gutnicella cayeuxi, pseudocyclammina maynci, spiraloconulus perconigi, s. giganteus, timi­ donella sarda in the aalenian and early bajocian, s. giganteus, pseudodictyopsella jurassica and marzoella ficcarellii in the bajocian, paravalvulina complicata at the end of bajocian and beginning of the bathonian, �9velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... as well as pseudoeggerella elongata, paleopfenderina salernitana, p. trochoidea, alzonella cuvillieri, orbita­ mmina elliptica, kilianina blancheti, satorina apuli­ ensis and s. mesojurassica in the bathonian. among the cited species p. maynci, s. perconigi, s. giganteus, t. sarda, p. complicata, p. elongata, a. cuvillieri and o. elliptica had not been previously observed on the adcp. occurrences of p. jurassica and m. ficcarellii are not only the first on the adcp, but probably the first observations outside the type localities. upper jurassic deposits are characterized by numerous specimens of some taxa, but diversification was less pronounced, as well as there being a low number of index species. the most frequent are kurnubias – kurnubia jurassica, k. palastiniensis and k. wellingsi, and index fossils were labyrinthina mirabilis, alveosepta jaccardi, parur­ gonina caelinensis and kilianina? rahonensis. conico­ curnubia orbitoliniformis, anchispirocyclina lusitanica and/or a. neumannae are documented for the first time on the adcp. cretaceous assemblages are much richer than trias­ sic and jurassic ones. taxa of wider stratigraphic rang­ es through the cretaceous are predominant. from the beginning of the early cretaceous to the late barremi­ an the most important index forms were protopenerop­ lis ultragranulata in the early berriasian, montsalevia salevensis, haplophragmoides joukowskyi, meandros­ pira favrei, vercorsella tenuis and v. camposaurii in the valanginian and early hauterivian, and campanellula capuensis in the late hauterivian. from the late bar­ remian and early aptian to the middle and late ceno­ manian, the most important species were orbitolinids and alveolinids, accompanied by taxa from different foraminiferal groups. index forms include rectodic­ tyoconus giganteus and palorbitolina lenticularis in the late barremian, p. lenticularis, paleodictyoconus actinostoma, praeorbitolina cormyi, p. wienandsi, mes­ orbitolina lotzei, voloshinoides murgensis, sabaudia briacensis, choffatella decipiens, derventina filipescui, neotrocholina friburgensis, n. aptiensis, trocholina lenticularis, pfenderina globosa and pseudolituonella conica in the early aptian, mesorbitolina parva, m. texana, archalveolina reicheli, sabaudia capitata and orbitolinopsis aquitanica in the late aptian, m. parva, m. texana, m. pervia, m. subconcava, paracoskinolina sunnilandensis, a. reicheli and s. capitata in the early albian, as well as ‘valdanchella’ dercourti, neoiraquia insolita, n. convexa, simplorbitolina broennimanni, paracoskinolina fleuryi, protochrysalidina elongata and ovalveolina maccagnoae in the late albian. in addition to orbitolinids and alveolinids, upper creta­ ceous deposits also contain nezzazatids, chrysalinids, miliolids and soritids. however, despite relatively rich fossil assemblages within certain sequences, which comprise all or part of some epochs, e.g. a stratigraphic range of turonian–early santonian, there are no index forms of short stratigraphic range. the most important index forms are: ovalveolina maccagnoae, o. crassa, sellialveolina viallii, orbitolina gr. concava, conicor­ bitolina conica, c. cuvillieri, praealvelina iberica and p. simplex in early cenomanian, chrysalidina gradata, nummoloculina? regularis, pseudolituonella reicheli, pastrikella balcanica, conicorbitolina conica, c. gr. corbarica–conica, orbitolina gr. sefini–concava, pseu­ dorhapydionina dubia and peneroplis turonicus in the middle cenomanian, c. gradata, n.? regularis, p. reicheli, p. balcanica, p. dubia, cisalveolina fraasi, vidalina radoicicae, v. hispanica, pseudorhapydionina laurinensis, pseudorhipidionina casertana and pen­ eroplis parvus in the late cenomanian, pseudorhapy­ dionina mediterranea, murgella lata, keramosphaerina tergestina, pseudocyclammina massiliensis, pseudol­ ituonella marie, spirolina cretacea, minouxia lobata, broekinella neumannae, reticulinella fleuryi, dicty­ opsella kiliani, dictyopselloides cuvillieri and orbi­ toides gr. hottingeri in the late santonian and early campanian, p. mediterranea, k. tergestina, p. mas­ siliensis, reticulinella reicheli, r. fleuryi, d. kiliani, d. cuvillieri, calveziconus lecalvezae, nummofallotia cretacea, praesiderolites douvillei, orbitoides douvil­ lei, o. tissoti, o. media and pseudosiderolites vidali in the late campanian, and murciella cuvillieri, m. renzi, rhapydionina liburnica, fleuryana adriatica, laffittei­ na mengaudi, o. media, siderolites calcitrapoides and omphalocyclus macroporus in the maastrichtian. biostratigraphic zonation was performed on depos­ its ranging from the carnian to the maastrichtian. low­ er and middle triassic rocks have not been investigated sufficiently in order to propose a reliable subdivision. with respect to previous knowledge on the biostratig­ raphy of shallow­marine, platform carbonate deposits of the mediterranean area, a new, more detailed bios­ tratigraphic subdivision is proposed. the following bio­ zones were defined: – within upper triassic deposits: lamelliconus procerus taxon­range zone, lamelliconus procerus–triasina hantkeni interval zone, triasina hantkeni taxon­range zone, and triasina hantkeni–mesoendothyra sp. interval zone; – within lower jurassic deposits: triasina hantkeni–mesoendothyra sp. interval zone, mesoendothyra sp. lineage zone, lituosepta recoarensis lineage zone, orbitopsella primaeva lineage zone, orbitopsella primaeva–lituosepta recoarensis con­ current­range subzone, lituosepta recoarensis–orbitopsella praecursor interval subzone, orbitopsella praecursor taxon­range zone, orbitopsella praecursor–orbitopsella primaeva con­ current­range subzone, orbitopsella praecursor abundance subzone, �0 geologia croatica 60/1 orbitopsella praecursor–pseudocyclammina liassica interval zone, pseudocyclammina liassica taxon­range zone, and pseudocyclammina liassica–gutnicella cayeuxi interval zone; – within middle jurassic deposits: pseudocyclammina liassica–gutnicella cayeuxi interval zone gutnicella cayeuxi partial­range zone, timidonella sarda taxon­range zone, timidonella sarda–pseudodictyopsella jurassica interval zone, pseudodictyopsella jurassica and marzoella ficcarel­ lii assemblage zone, pseudodictyopsella jurassica–paravalvulina compli­ cata interval zone, paravalvulina complicata taxon­range zone, paleopfenderina salernitana taxon­range zone, satorina apuliensis taxon range subzone, paleopfenderina salernitana–kurnubia jurassica interval zone, and kurnubia jurassica lineage zone; – within upper jurassic deposits: kurnubia palastiniensis superzone, kurnubia palastiniensis lineage zone, kurnubia wellingsi lineage zone, chablaisia chablaisensis–alveosepta jaccardi inter­ val zone, alveosepta jaccardi partial­range zone, parurgonina caelinensis–conicokurnubia orbitolini­ formis concurrent range­zone, conicokurnubia orbitoliniformis–kurnubia palasti­ niensis interval zone (highest occurrence zone), kurnubia palastiniensis–protopeneroplis ultragranu­ lata interval zone, and protopeneroplis ultragranulata taxon­range zone; – within lower cretaceous deposits: protopeneroplis ultragranulata taxon­range zone, protopeneroplis ultragranulata–vercorsella campo­ saurii interval zone, vercorsella camposaurii taxon­range zone, vercorsella camposaurii–campanellula capuensis interval zone, campanellula capuensis taxon­range zone, campanellula capuensis–palorbitolina lenticularis interval zone palorbitolina lenticularis superzone, rectodictyoconus giganteus and palorbitolina lenti­ cularis assemblage zone, praeorbitolina cormyi lineage zone, praeorbitolina wienandsi lineage zone, mesorbitolina lotzei lineage zone, mesorbitolina parva lineage zone, mesorbitolina texana lineage zone, mesorbitolina subconcava taxon­range zone, ‘valdanchella dercourti’ partial­range zone, and neoiraquia convexa taxon­range zone; – within upper cretaceous deposits: conicorbitolina conica/conicorbitolina cuvillieri partial­range zone, chrysalidina gradata superzone, chrysalidina gradata partial­range zone, pastrikella balcanica–conicorbitolina conica con­ current­range zone, vidalina radoicicae–chrysalidina gradata concur­ rent­range zone, chrysalidina gradata–pseudocyclammina sphaeroi­ dea interval zone, pseudocyclammina sphaeroidea–scandonea samni­ tica interval zone, scandonea samnitica–dicyclina schlumbergeri inter­ val zone, dicyclina schlumbergeri–murgella lata interval zone, murgella lata partial­range zone, keramosphaerina tergestina abundance subzone, calveziconus lecalvezae taxon­range zone, calveziconus lecalvezae–murciella cuvillieri inter­ val zone, murciella cuvillieri and rhapydionina liburnica assemblage zone, and fleuryana adriatica taxon­range subzone. with a total of 64 biozones in the stratigraphic range from the carnian to maastrichtian this is up to now not only the most detailed subdivision of the shallow­ marine carbonate deposits of the karst dinarides, but also in the wider tethyan/mediterranean area. palaeobiogeographic analysis of the adriatic car­ bonate platform deposits indicated similarities and dif­ ferences of biotopes and foraminiferal assemblage com­ positions between the adcp and other tethyan shallow­ marine areas. close similarities with neighbouring peri­ adriatic platforms are especially important, as well as changes in the platform position within the neotethyan realm, from individualization in the triassic and ear­ ly jurassic to disintegration in the late cretaceous. it may be concluded, that from its individualization to the late albian the adcp represented part of the southern neotethyan palaeobiogeographic province, while during the cenomanian it was probably palaeobiogeographi­ cally isolated from both main neotethyan bioprovinces, and together with the neighbouring periadriatic carbon­ �1velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... ate platforms represented part of the central mediterra­ nean province until its final disintegration in the latest cretaceous. during a span of almost 280 my, i.e. from the moscovian to the end of the eocene in the area of the present karst dinarides, approximately 8000 m of almost pure carbonates was deposited, most of them mesozoic in age. deposits of the adriatic carbonate platform, representing a succession from the toarcian to the end of the cretaceous, are up to 6500 m thick, and they had only been partially adequately investi­ gated. they were mostly relatively poorly subdivided, and some sequences were almost completely undivid­ ed. therefore, this paper will contribute to the more detailed stratigraphic subdivision of the late triassic, jurassic and cretaceous. the results presented here may represent a sound foundation for future investigation of these deposits in the karst dinarides, especially those dealing with chronostratigraphy. acknowledgement i would like to thank so many of my colleagues and collaborators for various forms of help during the writing and finalization of this paper, including many discussions and suggestions on stratigraphic ranges of some foraminiferal species within different parts of the karst dinarides. i would like to thank my colleagues who collaborated with me during the last four decades, and especially to: – branko sokač (croatian geological survey – hgi– cgs) for his long­lasting collaboration, support and countless discussions on the stratigraphy of mesozoic benthic foraminifera, their assemblages, and relationships with calcareous algae; – igor vlahović (formerly hgi–cgs, now with the university of zagreb, faculty of mining, geology and petroleum engineering) for continuous support, discussions on the importance of foraminifera for mesozoic stratigraphy and palaeogeography of the adriatic carbonate platform and karst dinarides, as well as for the translation of this paper; – tonći grgasović (hgi–cgs) for discussions on triassic foraminifera; – antun husinec (formerly hgi–cgs, now with the st. lawrence university, department of geology, canton, ny, usa) for discussions on late jurassic and early cretaceous foraminifera; – ladislav fuček (hgi–cgs) for discussion on cretaceous, especially late cretaceous foraminifera; – milka sarkotić-šlat, head of the hgi– cgs laboratory and technicians t. škrtić, d. galović and đ. novoselec for thin-sections; – goran mikša (ina oil indutry plc., research and development sector) for microphotographs of the largest foraminifera (orbitopsella, rectodictoconus, murgella, keramosphaerina, etc.); – ivo suša, hgi–cgs technician, for preparation of figures; – miroslav kladnički, hgi–cgs technician, for preparation of tables; – blanka cvetko tešović (university of zagreb, faculty of natural sciences), for providing thin­ sections with murciella cuvillieri; – katica drobne (palaeontological institute i. rakovac of the slovenian academy of sciences and arts, ljubljana, slovenia) for photomicrographs of fleuryana adriatica and microspheric rhapydionina liburnica. i am especially grateful to the reviewers – blanka cvetko tešović and ivan gušić (both university of zagreb, faculty of natural sciences) and vladimir veseli (ina oil indutry plc., research and development sector) – for their reviews enabling the improvement of this paper, but also for long­ lasting cooperation and discussions on taxonomy and stratigraphy of the mesozoic benthic foraminifera, as well as to felix schlagintweit (university of leoben, austria) for his very valuable suggestions and correction of some very important data, resulting in the significant improvement of this paper. also, i would like to thank julie robson (open university milton keynes, uk) for the language review. this paper represents the results of investigations performed with the support of the ministry of science, education and sports of the republic of croatia through the project 181–1953068–0242: ‘microfossil assemblages in carbonate deposits of the karst dinarides’. 6. references anić, d. (1962): prilog poznavanju jure i krede istočnog dijela biokova (beiträge zur kenntnis der jura­ und krei­ deschichten des östlichen teiles des biokovo gebirges).– geol. vjesnik, 15/1, 161–176. antonijević, r., pavić, a., karović, j., dimitrijević, m., radoičić, r., pejović, d., pantić, s. & roksandić, m. (1973): osnovna geološka karta sfrj 1:100.000. tumač za listove kotor i budva k34–50 i k34–62 (basic geological map of sfry 1:100.000. geo­ logy of the kotor and budva sheets).– zavod za geološka i geofizička istraživanja beograd (1969), savezni geološki zavod beograd, 64 p. arnaud, h., arnaud­vanneau, a., blanc­alé­ tru, m.c., adatte, t., argot, m., delanoy, g., thieuloy, j.p., vermeulen, j., virgone, a., vir­ louvet, b. & wermeille, s. (1998): répartition stratigraphique des orbitolinidés de la plate-forme urgo­ nienne subalpine et jurassienne (se de la france).– géol. alpine, 74, 3–89. �2 geologia croatica 60/1 arnaud-vanneau, a. (1980): micropaléontologie, paléoécologie et sédimentologie d’une plate-forme carbonatée de la marge passive de la téthys: l’urgonien du vercors septentrional et de la chartreuse (alpes occidentales).– géol. alpine, mem., 11, 874 p. arnaud­vanneau, a., conrad, m.a., deloffre, r., luperto­sinni, e., masse, j.p., peybernés, b., radoičić, r., sokač, b. & velić, i. (1991): distribution of lower cretaceous foraminifera and dasy­ cladal algae of the adriatic plate.– in: vlahović, i. & velić, i. (eds.): some aspects of the shallow water sedimentation on the adriatic carbonate platform (permi­ an to eocene). the second int. symp. on the adriatic car­ bonate platform, zadar, 1991, inst. of geology zagreb, abstracts, 22–26. bassoullet, j.p. (1997): les grands foraminifères.– in: cariou, e. & hantzpergue, p. (coord.): biostra­ tigraphie du jurassique ouest-européen et méditerranéen. bull. centre rech. elf. explor. prod., mem, 17, 293–304. bassoullet, j.p., chabrier, g. & fourcade, e. (l976): données complémentaires sur la morphologie, la structure interne et la position stratigraphique de timido­ nella sarda (foraminifère, lituolidae).– revue de micro­ paléontologie, 19/1, 3–18. bassoullet, j.p., fourcade, e. & peybernès, b. (l985): paléobiogéographie des grands foraminifères ben­ thiques des marges néotéthysiennes au jurassique et au crétacé inférieur.– bull. soc. géol. france, 85, 699–713. belak, m., koch, g., grgasović, t., vlahović, i., velić, i., sokač, b. & benček, đ. (2005): novi prinosi stratigrafiji evaporitno–karbonatno–klastično–vul­ kanogenog kompleksa komiškog zaljeva (otok vis, hrvat­ ska) (new contribution to the stratigraphy of evaporitic– carbonate–clastic–volcanogenic complex of the komiža bay, island of vis, croatia).– in: velić, i., vlahović, i. & biondić, r. (eds.): 3. hrv. geol. kongres – 3rd croatian geological congress, opatija 2005, knjiga sažetaka – abstracts book, zagreb, 13–14. bilotte, m. (1985): le crétacé supérieur des plates-formes est-pyrénéennes.– strata (2), 5, 1–438. bucković, d., cvetko tešović, b., jelaska, v. & gušić, i. (2003): the jurassic succession of mt. svila­ ja.– in: vlahović, i. & tišljar, j. (eds.): evolution of depositional environments from the palaeozoic to the quaternary in the karst dinarides and pannonian basin. 22nd ias meeting of sedimentology, opatija 2003, field­ trip guidebook, zagreb, 73–81. bucur, i.i. (1993): les reprépresentants du genre proto­ peneroplis weynschenk dans le dépôts du crétacé inférieur da la zone de reşiţa-moldova nouǎ (carpathes méridionales, roumanie).– revue de micropaléontologie, 36/3, 213–223. bucur, i.i., koch, r., kirmaci, z.m. & tasli, k. (2004): foraminifères du jurassique supérieur et du créta­ cé inférieur (calcaire de berdiga) de kircaova (région de kale-–gümüshane, ne turquie).– revue de paléobiolo­ gie, 23/1, 209–225. bukovac, j., velić, i. & sokač, b. (1974): stratigraf­ ski, tektonski i paleogeografski odnosi u području duga­ rese, barilovića i skradske gore (stratigraphy, tectonics and paleogeography of the region between dugaresa, barilović and skradska gora).– geol. vjesnik, 27, 59–77. bukovac, j., poljak, m., šušnjar, m. & čakalo, m. (1984): osnovna geološka karta sfrj 1:100.000. tumač za list črnomelj l33–91 (basic geological map of sfry 1:100.000. geology of the črnomelj sheet).– geološki zavod zagreb, geološki zavod ljubljana (1983), savezni geološki zavod beograd, 63 p. buser, s. (1986): osnovna geološka karta sfrj 1:100.000. tolmač listov tolmin in videm l33–64, l33–63 (basic geological map of sfry 1:100.000. geology of the tolmin and videm sheets).– geološki zavod ljubljana (1985), savezni geološki zavod beograd, 103 p. castro, j.m., company, m., de gea, g.a. & aguado, r. (2001): biostratigraphy of the aptian–middle cenomanian platform to basin domain in the prebetic zone of alicante, se spain: calibration between shallow water benthonic and pelagic scales.– cretaceous research, 22, 145–156. charollais, j., brönnimann, p. & zaninetti, l. (1966): troisième note sur les foraminifères du crétacé inférieur de la région genevoise. remarques stratigra­ phiques et description de pseuditextulariella salevensis, n.sp.; haplophragmoides joukowskyi, n.sp.; citaella? favrei, n.sp.– arch. sc. genève, 19/1, 23–48. cherchi, a. & schroeder, r. (1977): la forma micro­ sferica di lamarmorella sarda cherchi e schroe­ der, 1975 (foraminiferida).– boll. soc. paleont. ital., 16/2, 239–243. cherchi, a. & schroeder, r. (1980): broeckina (pas­ trikella) biplana n.sp., noveau grand foraminifère du cénomanien basal de la montagna de tauch (corbières, pyrénées françaises).– c. r. acad. sc. paris, (d), 290, 319–322. cherchi, a. & schroeder, r. (1985): broeckina (pas­ trikella) biplana.– in: schroeder, r. & neumann, m. (eds., 1985): les grands foraminifères du crétacé moyen de la région méditerranéenne. geobios, mém. spéc., 7, 97–98. cherchi, a., de castro, p. & schroeder, r. (1978): sull’età dei livelli a orbitolinidi della campania e del­ le murge baresi (italia meridionale).– boll. soc. natur. napoli, 87, 1–17. chiocchini, m. & mancinelli, a. (2000): marzoel­ la ficcarellii n.gen., n.sp. (foraminiferida) nel dogger del lazio nord­orientale (italia).– bolletino della società paleontologia italiana, 39/1, 21–28. chiocchini, m., farinacci, a., mancinelli, a., molinari, v. & potetti, m. (1994): biostratigrafia a foraminiferi, dasicladali e calpionelle delle successioni carbonatiche mesozoiche dell’appennino centrale (ita­ lia).– studi geologici camerti, vol. spec., 1994, “biostra­ tigrafia dell’italia centrale”, 9–129. clavel, b., charollais, j., schroeder, r. & bus­ nardo, r. (1995): réflexions sur la biostratigraphie du crétacé inférieur et sur sa complémentarité avec l’analyse séquentielle: exemple de l’urgonien jurassien et subal­ pin.– bull. de la soc. géol. de france, 166, 663–680. cvetko tešović, b. (2000): stratigrafija donje krede odabranih lokaliteta zapadne hrvatske (lower creta­ �3velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... ceous stratigraphy at selected localities in western croa­ tia).– unpubl. phd thesis (in croatian with summary in english), university of zagreb, faculty of natural sci­ ences, 263 p. cvetko tešović, b., gušić, i., jelaska, v. & bucković, d. (2001): stratigraphy and microfacies of the upper cretaceous pučišća formation, island of brač, cro­ atia.– cretaceous research, 22/5, 591–613. de castro, p. (1966): contributo alla conoscenza delle alveoline albiano–cenomaniane della campania.– boll. soc. natur. napoli, 75, 219–275. de castro, p. (1980): le alveoline aptiano–cenomaniane del mediterraneo centrale e orientale: sintesi e problemi.– universita degli studi di napoli, istituto di paleontologia, 1–86. de castro, p. (1988): les alvéolinidés du crétacé d’ita­ lie.– revue de paléobiologie, vol. spéc. 2, benthos ‘86, 401–416. de castro, p., drobne, k. & gušić, i. (1994): fleury­ ana adriatica n.gen., n.sp. (foraminiferida) from the uppermost maastrichtian of the brač island (croatia) and some other localities on the adriatic carbonate platform.– razprave iv razreda sazu ljubljana, 35/8, 129–149. dercourt, j., gaetani, m., vrielynck, b., bar­ rier, e., biju­duval, b., brunet, m.f., cadet, j.p., crasquin, s. & sandulescu, m. (eds., 2000): atlas peri­tethys, palaeogeographical maps.– ccgm/ cgmw, paris: 24 maps and explanatory notes: i–xx; 269 p. dragičević, i. & velić, i. (2002): the northeastern mar­ gin of the adriatic carbonate platform.– geol. croatica, 55/2, 185–232. drobne, k., ogorelec, b., pleničar, m., barat­ tolo, f., turnšek, d. & zucchi-stolfa, m.l. (1989): the dolenja vas section, a transition from cre­ taceous to paleocene in the nw dinarides, yugoslavia.– mem. soc. geol. it., 40 (1987), 73–84. đokić, v., živaljević, m. & perović, z. (1976): osno­ vna geološka karta sfrj 1:100.000 list gusinje k34–52 (basic geological map of sfry 1:100.000. geology of the gusinje sheet).– zavod za geološka istraživanja titograd (1968), savezni geološki zavod beograd, 49 p. farinacci, a. & radoičić, r. (1964): correlazione fra serie giuresi e cretacee dell’appennino centrale e delle dinaridi esterne.– la ricerca scientifica, 34/2, 269–300. fleury, j.j. (1980): les zones de gavrovo–tripolitza et du pinde–olnos (grèce continentale et péloponèse du nord). evolution d’une plate­forme et d’un bassin dans leur cadre alpin.– publ. soc. géol. du nord, 4, 1–651. fleury, j.j., bignot, g., blondeau, a. & poignant, a. (1985): biogéographie de foraminifères benthiques téthysiens du sénonien à l’éocène supérieur.– bull. soc. géol. france, (8), 1/5, 757–770. frijia, g. & parente, m. (2007) : isotope-stratigraphy in turonian–campanian shallow­water carbonates of southern apennines (italy).– geophysical research abs­ tract, 9, sref­id: 1607­7962/gra/egu2007­a­06819, european geoscience union 2007. fuček, l., gušić, i., jelaska, v., korolija, b. & oštrić, n. (1990): stratigrafija gornjokrednih naslaga jugoistočnog dijela dugog otoka i njihova korelacija s istovremenim naslagama otoka brača (upper cretaceous stratigraphy of the se part of the dugi otok island and its correlation with the corresponding deposits of the brač island, adriatic carbonate platform).– geol. vjesnik, 43, 23–33. fuček, l., velić, i., vlahović, i., oštrić, n., korolija, b. & matičec, d. (1995): novi podaci o strati­ grafiji donje krede otoka cresa.– in: vlahović, i., velić, i. & šparica, m. (eds.): 1. hrv. geol. kongres zbornik radova, 1 (first croat. geol. congress, procee­ dings, 1), 167–172. gendrot, c. (1968): stratigraphie et micropaléontologie du sénonien de la région des martigues près marseille (bou­ ches-du-rhône).– eclogae geol. helv., 61/2, 657–694. gradstein, f.m., ogg, j.g., smith, a.g., agter­ berg, f.p., bleeker, w., cooper, r.a., davy­ dov, v., gibbard, p., hinnov, l., house, m.r., lourens, l., luterbacher, h.­p., mcarthur, j., melchin, m.j., robb, l.j., shergold, j., ville­ neuve, m., wardlaw, b.r., ali, j., brinkhuis, h., hilgen, f.j., hooker, j., howarth, r.j., knoll, a.h., laskar, j., monechi, s., powell, j., plumb, k.a., raffi, i., röhl, u., sanfilippo, a., schmitz, b., shackleton, n.j., shields, g.a., strauss, h., van dam, j., veizerm j., van kolfschoten, th. & wilson, d. (2004): a geolo­ gic time scale.– cambridge university press, 611 p. grgasović, t. (1997): upper triassic biostratigraphy and algae from žumberak (croatia).– geol. croatica, 50/2, 201–214. grgasović, t. (2003): revizija rodova physoporella steinmann i oligoporella pia (dasycladales) (revisi­ on of genera physoporella steinmann and oligoporel­ la pia (dasycladales)).– unpubl. phd thesis (in croatian with english summary), university of zagreb, faculty of natural sciences, viii+484 p. grgasović, t., halamić, j., goričan, š., slovenec, d. & kolar-jurkovšek t. (2000): trijaske dubokomorske naslage odabranih lokaliteta u sjevero­ zapadnoj hrvatskoj (triassic deep­water sediments of selected localities in northwestern croatia).– 2. hrv. geol. kongres cavtat–dubrovnik, zbornik radova zagreb (second croat. geol. congress, proceedings), 181–188. gušić, i. (1969a): some new and inadequately known juras­ sic foraminifers from central croatia.– geol. vjesnik, 22, 55–87. gušić, i. (1969b): biostratigraphic and micropaleontologic characteristics of some jurassic cross­sections in central croatia.– geol. vjesnik, 22, 89–97. gušić, i. (1977): a new foraminiferal family biokovinidae from the jurassic of the dinarids and its phylogenetic rela­ tionships.– palaeont. jugosl., 18, 1–31. gušić, i. (1981): variation range, evolution, and biostrati­ graphy of palorbitolina lenticularis (blumenbach) (foraminiferida, lituolacea) in the lower cretaceous of the dinaric mountains in yugoslavia.– paläont. z., 55, 3/4, 3–4, 191–208. �� geologia croatica 60/1 gušić, i. & babić, lj. (1970): neke biostratigrafske i litogenetske osobine jure žumberka (some biostratigraphic and lithogenetic characteristics of the jurassic in žumberak, northwest croatia).– geol. vjesnik, 23, 39–54. gušić, i. & jelaska, v. (1990): stratigrafija gornjokred­ nih naslaga otoka brača u okviru geodinamske evolucije jadranske karbonatne platforme (upper cretaceous strati­ graphy of the island of brač within the geodynamic evo­ lution of the adriatic carbonate platform).– djela jazu, zagreb, 69, 1–160. gušić, i. & jelaska, v. (1993): upper cenomanian–low­ er turonian sea­level rise and its consequences on the adriatic–dinaric carbonate platform.– geol. rundsch., 82/4, 676–686. gušić, i. & velić, i. (1978): lituolipora polymorpha n.gen., n.sp. (foraminiferida, lituolacea?) from the middle liassic of the outer dinarids in croatia and the establishment of a new family lituoliporidae (lituolipo­ ra polymorpha n.gen., n.sp. (foraminiferida, lituolacea?) iz srednjeg lijasa vanjskih dinarida hrvatske i uspostav­ ljanje nove porodice lituoliporidae).– geol. vjesnik, 30/1, 73–93. gušić, i., nikler, l. & sokač, b. (1971): the jurassic in the dinaric mountains of croatia and the problems of its subdivision.– ann. inst. geol. publ. hungar., 54/2, 165–173. gušić, i., jelaska, v. & velić, i. (1988): foraminiferal assemblages, facies and environments in the upper cre­ taceous of the island of brač.– revue de paleobiologie, vol. spec. 2, benthos ‘86, 447–456. hamaoui, m. (1979): contribution a l’étude du cénoma­ no–turonien d’israel comparaisons micropaléontologi­ ques avec quelques régions mésogéennes.– unpubl. phd thesis, l’université pierre et marie curie paris, 121 p. hottinger, l. (1967): foraminifères imperforés du méso­ zoïque marocain.– notes mém. serv. géol. maroc, 209, 1–168. hottinger, l., drobne, k. & caus, e. (1989): late cretaceous, larger, complex miliolids (foraminifera) ende­ mic in pyrenean faunal province.– facies, 21, 99–134. husinec, a., velić, i., fuček, l., vlahović, i., matičec, d., oštrić, n. & korbar, t. (2000): mid cretaceous orbitolinid (foraminiferida) record from the islands of cres and lošinj (croatia).– cretaceous research, 21, 155–171. jaffrezo, m. (1980): les formations carbonatées des cor­ bières (france) du dogger à l’aptien: micropaléontologie, stratigraphique, biozonation, paléoécologie. extension des résultats à la mésogée.– unpubl. phd thesis, univ. pierre et marie curie paris vi, xvii+614+23 p. jelaska, v., gušić, i., jurkovšek, b., ogorelec, b., ćosović, v., šribar, lj. & toman, m. (1994): the upper cretaceous geodynamic evolution of the adri­ atic–dinaric carbonate platform(s).– geol. mediterr., 21/3–4, 89–91. jenkyns, h.c. (1988): the early toarcian (jurassic) anoxic event: stratigraphic, sedimentary, and geochemical evi­ dence.– am. j. sci., 288, 101–151. jenkyns, h.c. (1991): impact of cretaceous sea­level rise and anoxic events in the mesozoic carbonate platform of yugoslavia.– aapg bull., 75, 1007–1017. jurkovšek, b., toman, m., ogorelec, b., šribar, l., drobne, k., poljak, m. & šribar, lj. (1996): formacijska geološka karta južnega dela tržaško– komenske planote: kredne in paleogenske karbonatne kamnine 1:50000 (geological map of the southern part of the trieste–komen plateau: cretaceous and paleogene carbonate rocks).– inštitut za geologijo, geotehniko in geofiziko ljubljana, 143 p. kabal, y. & tasli, k. (2003): biostratigraphy of the low­ er jurassic carbonates from the aydincik area (central taurides, s turkey) and morphological analysis of lituoli­ pora termieri (hottinger, 1967).– journal of forami­ niferal research, 33/4, 338–351. kalezić, m., mirković, m. & škuletić, d. (1973): osnovna geološka karta sfrj 1:100.000. tumač za list šavnik k34–39 (basic geological map of sfry 1:100.000. geology of the šavnik sheet).– zavod za geološka istraživanja titograd (1966), savezni geološki zavod beograd, 65 p. kochansky-devidé & pantić, (1966): meandrospira u donjem i srednjem trijasu i neki popratni fosili u dina­ ridima (meandrospira in der unteren und mittleren trias sowie einige begleitende fossilien in den dinariden).– geol. vjesnik, 19, 15–28. korbar, t., fuček, l., husinec, a., vlahović, i., oštrić, n., matičec, d. & jelaska, v. (2001): cenomanian carbonate facies and rudists along shallow intraplatform basin margin – the island of cres (adriatic sea, croatia).– facies, 45, 39–58. korolija, b., živaljević, t. & šimunić, an. (1981): osnovna geološka karta sfrj 1:100.000. tumač za list slunj l33–104 (basic geological map of sfry 1:100.000. geology of the slunj sheet).– institut za geološka istraživanja zagreb (1972), geološki zavod sarajevo (1968), savezni geološki zavod beograd, 47 p. luperto sinni, e. (1968): microfauna bathoniana del m. alpi.– boll. soc. natur. napoli, 77, 181–206. luperto sinni, e. (1976): microfossili senoniani delle murge.– riv. ital. paleont., 82/2, 293–416. luperto sinni, e. & ricchetti, g. (1978): studio micropaleontologico–stratigrafico di una successione car­ bonatica del cretaceo superiore rilevata nel sottosuolo del­ le murge sud­orientali.– riv. ital. paleont., 84/3, 561–666. mamužić, p. & grimani, m. (1970): mikrofosilne zajed­ nice gornje krede otočnog i obalnog dijela hrvatske (pre­ liminarna podjela) (microfossil assemblages of the upper cretaceous of the croatian island and coastal region; in croatian).– vii kongres geologa sfrj zagreb, 1, 177– 182. mamužić, p., polšak, a., grimani, m. & magaš, n. (1976): biostratigrafske i litofacijelne karakteristi­ ke gornje krede sjeveroistočnih padina biokova u južnoj hrvatskoj (biostratigraphic and lithofacial characteristics of the upper cretaceous of northeastern slopes of bioko­ vo in southern croatia).– viii jugosl. geol. kongres bled (1974), ljubljana, 2, 167–180. mamužić, p., polšak, a., grimani, m., šimunić, al. & korolija, b. (1980): detaljni geološki stup kroz naslage cenomana sjeverno od vela luke na otoku korču­ li (detailed geological column through cenomanian depo­ ��velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... sits north of vela luka, island of korčula, dalmatia, sout­ hern croatia).– geol. vjesnik, 31, 91–103. mamužić, p., polšak, a., grimani, m., šimunić, al. & korolija, b. (1981a): detaljni geološki stup kroz naslage cenomana u zapadnom dijelu otoka hvara (collo­ ne stratigraphique détaillée du cenomanien et du turonien dans la partie occidentale de ľile de hvar).– geol. vjesnik, 33, 49–57. mamužić, p., korolija, b., grimani, m. & šimu­ nić, al. (1981b): detaljni geološki stupovi kroz naslage krede (gornji otriv–donji turon) središnjeg dijela poluo­ toka pelješca (collones géologiques à travers les couches cretacées (hauterivien supérieur–turonien inférieur) de la partie centrale de la presque île de pelješac).– geol. vjesnik, 34, 19–25. mamužić, p., polšak, a., grimani, m. & korolija, b. (1982): detaljni geološki stup kroz naslage cenomana i donjega turona u središnjem dijelu otoka cresa (collo­ ne stratigraphique détaillée à travers du cenomanien et du turonien inférieur dans la partie centrale de ľile de cres).– geol. vjesnik, 35, 65–70. mamužić, p., korolija, b., grimani, m. & šimu­ nić, al. (1983): geološki stup kroz naslage krede (raspo­ na gornji cenoman–donji senon) središnjega dijela poluo­ toka pelješca (collone stratigraphique détaillée à travers les couches cretacées (cénomanien supérieur–sénonien inférieur) dans la partie centrale de la presqu’ile de pel­ ješac).– geol. vjesnik, 36, 73–77. mamužić, p., grimani, m. & šimunić, al. (1984): geološki stup kroz naslage gornjeg turona i donjeg senona kod primoštena u dalmaciji (collone géologique à travers les couches du turonien supérieur–sénonien inférieur près de primošten en dalmatie centrale).– geol. vjesnik, 37, 55–58. marinčić, s. (1997): tectonic structure of the island of hvar (southern croatia) (tektonska struktura otoka hva­ ra).– geol. croatica, 50/1, 57–77. marinković, r. & đorđević, d. (1981): osnovna geološka karta sfrj 1:100.000. tumač za list jajce l33–131 (basic geological map of sfry 1:100.000. geology of the jajce sheet).– geoinženjering sarajevo (1975), savez­ ni geološki zavod beograd, 52 p. maritan, l., mazzoli, c. & melis, e. (2003): a mul­ tidisciplinary approach to the characterization of roman gravestones from aquileia (udine, italy).– archaeometry, 45/3, 363–374. marković, b. (1975): osnovna geološka karta sfrj 1:100.000. tumač za list dubrovnik k34–49 (basic geo­ logical map of sfry 1:100.000. geology of the gacko sheet).– zavod za geološka i geofizička istraživanja beo­ grad (1966), savezni geološki zavod beograd, 43 p. mirković, m. (1980): osnovna geološka karta sfrj 1:100.000. tumač za list gacko k34–26 (basic geological map of sfry 1:100.000. geology of the gacko sheet).– zavod za geološka istraživanja titograd (1974), savezni geološki zavod beograd, 67 p. mirković, m., kalezić, m., pajović, m., živaljević, m. & škuletić, d. (1978): osnovna geološka karta sfrj 1:100.000. tumač za list bar k34–63 (basic geological map of sfry 1:100.000. geology of the bar sheet).– zavod za geološka istraživanja titograd (1968), savezni geološki zavod beograd, 67 p. mojičević, m., vilovski, s., tomić, b. & pamić, j. (1977): osnovna geološka karta sfrj 1:100.000 list banjaluka l 33–119 (basic geological map of sfry 1:100.000, geology of the banjaluka sheet).– institut za geološka istraživanja sarajevo (1976), savezni geološki zavod beograd, 50 p. mojičević, m., pamić, j., maksimčev, s. & papeš, j. (1979): osnovna geološka karta sfrj 1:100.000. tumač za list bosanska krupa l 33–117 (basic geological map of sfry 1:100.000. geology of the bosanska krupa sheet).– geoinženjering sarajevo (1971), savezni geološki zavod beograd, 50 p. neagu, t. (1994): early cretaceous trocholina group and some related genera from romania (part i).– revista española de micropaleontologia, 26/3, 117–143. nikler, l. & sokač, b. (1968): biostratigraphy of the jurassic of velebit (croatia).– geol. vjesnik, 21, 161–176. pantić, s. (1965): pilammina densa, n.gen., n.sp. and other ammodiscidae from the middle triassic in crmnica (montenegro).– geol. vjesnik, 18/1, 189–192. pantić, s. (1966/67): turrispirillina minima n.sp. iz trijas­ kih sedimenata dinarida (turrispirillina minima n.sp. des sédiments triasiques des dinarides externes).– vesnik (a) beograd, 24/25, 255–258. pantić-prodanović, s. (1975): trijaske mikrofacije dinarida (les microfacies triasiques des dinarides).– druš­ tvo za nauku i umjetnost crne gore (soc. sci. arts mon­ ténégro) titograd, 4, odj. prir. nauka (classe sci. natur.), 4, 1–257. papeš, j. (1975): osnovna geološka karta sfrj 1:100.000. tumač za list livno k33–11 (basic geological map of sfry 1:100.000. geology of the livno sheet).– institut za geološka istraživanja sarajevo (1967), savezni geološki zavod beograd, 64 p. peybernès, b. (1976): le jurassique et le crétacé inféri­ eur des pyrénées franco–espagnoles entre la garonne et la méditerranée.– unpubl. phd thesis, univ. tolouse, 459 p. pfender, j. (1938): les foraminifères du valanginien pro­ vençal.– bull. soc. géol. france, 5/8, 231–242. polšak, a., bauer, v. & slišković, t. (1982): stratigraphie du crétacé supérieur de la plate-forme carbonatée dans les dinarides externes.– cretaceous research, 3, 125–133. radoičić, r. (1960): mikrofacije krede i starijeg tercijara spoljnih dinarida jugoslavije (microfaciès du crétacé et du paleogène des dinarides externes de yougoslavie).– zavod geol. istraž. nr crne gore (a) titograd. paleonto­ logija jugosl. dinarida, 4/1, 5–172. radoičić, r. (1966): microfaciès du jurassique des dinari­ des externes de la yougoslavie.– geologia, 9, 5–378. radoičić, r. (2005): new dasycladales and microbiota from the lowermost valanginian of the mirdita zone.– annales géologiques de la pénninsule balkanique, 66, 27–53. raić, v. & papeš, j. (1982): osnovna geološka karta sfrj 1:100.000. tumač za list ston k33–48 (basic geological �6 geologia croatica 60/1 map of sfry 1:100.000. geology of the ston sheet).– geoinženjering sarajevo, geološki zavod zagreb (1980), savezni geološki zavod beograd, 39 p. salvador, a. (ed., 1994): international stratigraphic guide. a guide to stratigraphic classification, terminology, and procedure.– international subcommission on stratigraphic classification (issc), second edition, xix+214 p. saint­marc, p. (1974): etude stratigraphique et micropa­ léontologique de l’albien, du cénomanien et du turonien du liban.– notes mémoires moyen–orient, 13, 1–342. saint-marc, p. (1977): répartition stratigraphique des grands foraminifères benthiques de l’aptien, de l’albien, du cénomanien et du turonien dans les régions méditer­ ranéennes.– rev. esp. de micropal., 9/3, 317–325. sartoni, s. & crescenti, u. (1962): ricerche biostratigrafische nel mezozoico dell’appennino meridionale.– giorn. geol. (2a), 29, 161–304. savić, d. & dozet, s. (1985): osnovna geološka karta sfrj 1:100.000. tumač za list delnice l33–90 (basic geological map of sfry 1:100.000. geology of the del­ nice sheet).– geološki zavod zagreb, geološki zavod ljubljana (1983), savezni geološki zavod beograd, 66 p. schroeder, r. (1962): orbitolinen des cenomans süd­ westeuropas.– paläont. z., 36, 171–202. schroeder, r. (1964a): zur evolution der cenoman­orbi­ tolinen. eine entgegnung an j. hofker jun.– n. jb. geol. paläont., mh., 1964, 682–693. schroeder, r. (1964b): communication préable sur l’ori­ gine des orbitolines.– c. r. soc. geol. france, 1964/10, 411–413. schroeder, r. (1964c): orbitoliniden biostratigraphie des urgons nordöstlich von teruel (spanien).– neues jahrb. für geol. u. paläont., mh., 462–473. schroeder, r. (1975): general evolutionary trends in orbitolinas.– revista española de micropaleontologia, num. esp., 117–128. schroeder, r. (1979): les orbitolines de l’aptien: défini­ tions, origine et évolution (the aptian orbitolinas – defi­ nitions, origin and evolution).– géobios mém. spéc., 3, 289–299. schroeder, r., cherchi, a., guellal, s. & vila, j.m. (1974): biozonation par les grands foraminifères du jurassique supérieur et du crétacé inférieur et moyen des séries néritiques en algérie ne. considérations palèobio­ gèographiques.– vi coll. africain micropal., tunis 1974, prétirage, 1–8. schroeder, r., clavel, b., cherchi, a., busnar­ do, r., charollais, j. & decrouez, d. (2002): lignées phylétiques d’orbitolinidés de l’intervalle haute­ rivien supérieur–aptien inférieur; leur importance strati­ graphique.– revue paléobiologie, 21/2, 853–863. schroeder, r. & neumann, m. (eds., 1985): les grands foraminifères du crétacé moyen de la région méditerranéenne.– geobios, mém. spéc., 7, 1–160. septfontaine, m. (1980): les foraminifères imperforés des milieux de plate-forme au mésozoïque: détermination pratique, interprétation phylogénétique et utilisation bios­ tratigraphique.– rev. micropaléont., 23/3–4, 169–203. septfontaine, m. (1984): biozonation (à l’aide des fora­ minifères imperforés) de la plate-forme interne carbona­ tée liasique du haut atlas (maroc).– rev. micropaléont., 27/3, 209–229. septfontaine, m. (1988): vers une clasification évoluti­ ve des lituolidés (foraminifères) jurassiques en milieu de plate­forme carbonatèe (towards an evolutionary classifi­ cation of jurassic lituolides (foraminifera), in carbonate platform environment).– rev. de paléobiol., vol. spec., 2, 229–256. septfontaine, m. & de matos, j.e. (1998): pseudodic­ tyopsella jurassica n.gen., n.sp., a new foraminifera from the early middle jurassic of the musandam peninsula, n. oman mountains; sedimentological and stratigraphical context.– rev. micropaléont., 41/1, 71–87. septfontaine, m., arnaud­vanneau, a., basso­ ullet, j.p., gušić, i., ramalho, m. & velić, i. (1991): les foraminifères imperforés des plate-formes carbonatées jurassiques: état des connaissances et perspec­ tives d’avenir.– bull. soc. vaud. sc. nat., 80/3, 255–277. sofilj, j., živanović, m. & pamić, j. (1980): osno­ vna geološka karta sfrj 1:100.000. tumač za list prozor k33–12 (basic geological map of sfry 1:100.000. geo­ logy of the prozor sheet).– institut za geološka istraživanja sarajevo (1971), savezni geološki zavod beograd, 49 p. sokač, b. (2001): lower and middle liassic calcareous algae (dasycladales) from mt. velebit (croatia) and mt. trnovski gozd (slovenia) with particular reference to the genus palaeodasycladus (pia, 1920) 1927 and its spe­ cies.– geol. croatica, 54/2, 133–257. sokač, b. & velić, i. (1978): biostratigrafska istraživanja donje krede vanjskih dinarida (i). neokom zapadne istre (biostratigraphic investigations of the lower cretaceous of the outer dinarids. the neocomian of western istria).– geol. vjesnik, 30/1, 243–250. sokač, b. & velić, i. (1979a): triassic, jurassic and low­ er cretaceous of the karst dinarids in the western croa­ tia.– 16th european micropal. coll. ljubljana, 79–100. sokač, b. & velić, i. (1979b): lower cretaceous in western istria. excursion j (limska draga).– 16th europe­ an micropal. coll. ljubljana., 209–216. sokač, b., tišljar, j. & velić, i. (1978): model biostratigrafskog raščlanjivanja i analiza sredina taloženja u kar­ bonatnim sedimentima donje krede biokova (a model of biostratigraphic subdivision and an interpretation of depo­ sitional environments in the lower cretaceous carbona­ te sediments of biokovo mountain, south croatia).– ix kongres geologa jugoslavije sarajevo, zbornik radova, 226–232. steuber, t., korbar, t., jelaska, v. & gušić, i. (2005): strontium­isotope stratigraphy of upper cretace­ ous platform carbonates of the island of brač (adriatic sea, croatia): implications for global correlation of plat­ form evolution and biostratigraphy.– cretaceous research, 26, 741–756. tasli, k. (1993): micropaléontologie, stratigraphie et envi­ ronnement de dépôt des séries jurassiques à faciès de plate-forme dela région de kale–gümüşhane (pontides orientales, turquie) (micropaleontology, stratigraphy and depositional environment of the jurassic carbonate plat­ �7velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... form sequence of kale–gümüşhane region, eastern pon­ tids, turkey).– rev. micropaléont., 36/1, 45–65. tišljar, j. & velić, i. (1993): upper jurassic (malm) shallow water carbonates in the western gorski kotar area: facies and depositional environments (western cro­ atia).– geol. croatica, 46/2, 263–279. tišljar, j., vlahović, i., sremac, j., velić, i., veseli, v. & stanković, d. (1991): excursion “a” – velebit mt., permian–jurassic.– in: vlahović, i. & velić, i. (eds.): “some aspects of the shallow water sedimentation on the adriatic carbonate platform (per­ mian to eocene)”. the second int. symp. on the adria­ tic carbonate platform, zadar, 1991., inst. of geology, zagreb, excursion guide­book, 1–49. tišljar, j., vlahović, i., velić, i. & sokač, b. (2002): carbonate platform megafacies of the jurassic and cretaceous deposits of the karst dinarides.– geol. croati­ ca, 55/2, 139–170. velić, i. (1973): stratigrafija krednih naslaga u graničnom području velike i male kapele (stratigraphy of the cre­ taceous deposits in the border region of velika kapela and mala kapela mountains, croatia).– geol. vjesnik, 26, 93–109. velić, i. (1977): jurassic and lower cretaceous assembla­ ge­zones in mt. velika kapela, central croatia.– acta geologica, 9/2, 15–37. velić, i. (1988): lower cretaceous benthic foraminiferal biostratigraphy of the shallow­water carbonates of the dinarides.– revue de paleobiologie, vol. spec. 2, benthos ‘86, 467–475. velić, i. (2005): “misterij dogera”: foraminiferske zajednice i stratigrafska raščlamba srednjojurskih naslaga u krškim dinaridima (jadranska karbonatna platforma) (benthic foraminifera assemblages and stratigraphic subdivision of the middle jurassic in karst dinarides, adriatic carbonate platform).– in: velić, i., vlahović, i. & biondić, r. (eds.): 3. hrvatski geološki kongres (3rd croatian geological congress), opatija, 2005, knjiga sažetaka (abstracts book), hrvatski geološki institut (croatian geological survey), 159–160, zagreb. velić, i. & sokač, b. (1974): on the tripartite subdivision of the malm in mt. velika kapela (croatia).– geol. vjes­ nik, 27, 143–150. velić, i. & sokač, b. (1978a): biostratigrafska analiza jure i donje krede šire okolice ogulina (središnja hrvat­ ska) (biostratigraphic analysis of the jurassic and lower cretaceous in wider region of ogulin, central croatia).– geol. vjesnik, 30/1, 309–337. velić, i. & sokač, b. (1978b): zone s orbitolinidama u krednim naslagama krškog dijela hrvatskih dinarida (orbitolinid biozones in the cretaceous deposits of the croatian karst dinarides).– ix kongres geologa jugosla­ vije sarajevo, zbornik radova, 215–222. velić, i. & sokač, b. (1979): younger lower cretaceous and lower cenomanian of central croatia. excursion c (karlovac–ogulin).– 16th european micropal. coll., ljub­ ljana, 147–156. velić, i. & sokač, b. (1980): biostratigrafska istraživanja donje krede vanjskih dinarida (ii). gornji alb otoka korčule (biostratigraphic investigations of the lower cretaceous of the outer dinarids (ii). the upper albian of the island of korčula).– geol. vjesnik (1979), 31, 185– 190. velić, i. & sokač, b. (1983): stratigraphy of the lower cretaceous index­fossils in the karst dinarides (yugosla­ via).– zitteliana, 10, 485–491. velić, i. & tišljar, j. (1988): litostratigrafske jedinice u dogeru i malmu zapadne istre, zapadna hrvatska, jugosla­ vija (lithostratigraphic units in the dogger and malm of western istria).– geol. vjesnik, 41, 25–49. velić, i. & vlahović, i. (1994): foraminiferal assem­ blages in the cenomanian of the buzet–savudrija area (northwestern istria, croatia).– geol. croatica, 47/1, 25– 43. velić, i., tišljar, j. & sokač, b. (1979): stratigraphy and depositional environments of the lower cretaceous in the karst region of the outer dinarides, yugoslavia (stratigraphie et paleoenvironnments du cretace inferieur dans la region karstique des dinarides externes, yougosla­ vie).– geobios, mem. spec., 3, 245–252. velić, i., sokač, b. & šćavničar, b. (1982): osno­ vna geološka karta sfrj 1:100.000. tumač za list ogu­ lin l33–103 (basic geologic map of sfry 1: 100.000. geology of the ogulin sheet).– geološki zavod zagreb (1980), savezni geol. zavod beograd, 46 p. velić, i., tišljar, j. & sokač, b. (1989): the variability of thicknesses of the barremian, aptian and albian carbo­ nates as a consequence of changing depositional environ­ ments and emersion in western istria (croatia, yugosla­ via).– mem. soc. geol. it., 40 (1987), 209–218. velić, i., matičec, d., vlahović, i. & tišljar, j. (1995): stratigrafski slijed jurskih i donjokrednih karbo­ nata (bat–gornji alb) u zapadnoj istri, ekskurzija a (stra­ tigraphic succession of jurassic and lower cretaceous carbonates (bathonian–upper albian) in western istria, excursion a).– in: vlahović, i. & velić, i. (eds.): 1. hrv. geol. kongres, vodič ekskurzija (first croat. geol. congress, exc. guide­book), 31–66. velić, i., vlahović, i. & matičec, d. (2002): deposi­ tional sequences and palaeogeography of the adriatic car­ bonate platform.– mem. soc. geol. it., 57, 141–151. venturini, s. (2005): l’evento a keramosphaerina ter­ gestina: cosiderazioni bio­cronostratigrafiche (the kera­ mosphaerina tergestina event: bio­chronostratigraphic aspects).– natura nascosta, 31, 15–22. veseli, v. (1999): facijesi karbonatnih sedimenata mlađeg mezozoika i paleogena u pučinskim bušotinama sjevernog jadrana (younger mesozoic and palaeogene carbonate deposits facies in the off­shore wells of the northern adri­ atic).– unpublished phd thesis, university of zagreb, 306 p. vlahović, i., tišljar, j. & velić, i. (1994): influence of synsedimentary tectonics and eustatic changes on depo­ sition of the cenomanian carbonates in istria (western croatia).– geol. mediterr., 21/3–4, 189–193. vlahović, i., tišljar, j., velić, i. & matičec, d. (2002): the karst dinarides are composed of relics of a single mesozoic platform: facts and consequences.– geol. croatica, 55/2, 171–183. �8 geologia croatica 60/1 vlahović, i., tišljar, j., velić, i., matičec, d., skelton, p.w., korbar, t. & fuček, l. (2003): main events recorded in the sedimentary succession of the adriatic carbonate platform from the oxfordian to the upper santonian in istria (croatia).– in: vlahović, i. & tišljar, j. (eds.): evolution of depositional environ­ ments from the palaeozoic to the quaternary in the karst dinarides and the pannonian basin. 22nd ias meeting of sedimentology, opatija – september 17–19 2003, field­ trip guidebook 19–56, zagreb. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dyna­ mics.– palaeogeography, palaeoclimatology, palaeoecolo­ gy, 220, 333–360. vrhovčić, j. & mojičević, m. (1983): osnovna geološka karta sfrj 1:100.000. tumač za list ključ l33–130 (basic geological map of sfry 1:100.000. geology of the ključ sheet).– geoinženjering sarajevo (1976), savez­ ni geološki zavod beograd, 40 p. vujisić, t. (1975): osnovna geološka karta sfrj 1:100.000. tumač za list nikšić k34–38 (basic geological map of sfry 1:100.000. geology of the nikšić sheet).– zavod za geološka i geofizička istraživanja beograd (1967), savez­ ni geološki zavod beograd, 53 p. vujnović, l. (1981): osnovna geološka karta sfrj 1:100.000. tumač za list bugojno l33–140 (basic geological map of sfry 1:100.000. geology of the bugojno sheet).– geoinženjering sarajevo (1975), savezni geološki zavod beograd, 58 p. živaljević, m., pajović, m., đokić, v. & škuletić, d. (1971): osnovna geološka karta sfrj 1:100.000. tumač za list titograd k34–51 (basic geological map of sfry 1:100.000. geology of the titograd sheet).– zavod za geološka istraživanja titograd (1967), savezni geološki zavod beograd, 57 p. živaljević, m., vujisić, p. & stijović, v. (1989): osnovna geološka karta sfrj 1:100.000. tumač za list žabljak k34–27 (basic geological map of sfry 1:100.000. geology of the žabljak sheet).– zavod za geološka istraživanja titograd (1987), savezni geološki zavod beograd, 62 p. manuscript received december 17, 2006. revised manuscript accepted april 10, 2007. �9velić: stratigraphy and palaeobiogeography of mesozoic benthic foraminifera... 1. foraminifera accordiella conica farinacci, 1962 agerina martana (farinacci, 1959) alveosepta jaccardi (schrodt, 1894) alzonella cuvillieri bernier & neumann, 1970 amijiella amiji (henson), 1948 ammobaculites radstadtensis kristan­tollmann, 1964 ammodiscus parapriscus (ho, 1959) anchispirocyclina lusitanica (egger, 1902) anchispirocyclina neumannae bernier, fleury & ramalho, 1979 archaealveolina sp. archaealveolina reicheli (de castro, 1966) archiacina munieri (marie, 1958) arenovidalina chialingchiangensis ho, 1959 auloconus permodiscoides (oberhauser, 1964) aulotortus sp. aulotortus friedli (kristan­tollmann, 1962) aulotortus pokornyi (salaj, 1967) aulotortus praegaschei (koehn­zaninetti, 1968) aulotortus sinuosus (weynschenk, 1956) aulotortus tenuis (kristan, 1957) aulotortus tumidus (kristan­tollmann, 1964) belorussiella textilarioides (reuss, 1863) biconcava bentori hamaoui & saint-marc, 1970 biokovina gradacensis gušić, 1977 biplanata peneropliformis hamaoui & saint-marc, 1970 bosniella oenensis gušić,1977 broekinella neumannae gendrot, 1968 calveziconus lecalvezae caus & cornella, 1981 campanellula capuensis de castro, 1964 chablaisia chablaisensis (septfontaine, 1977) charentia cuvillieri neumann, 1965 choffatella decipiens schlumberger, 1904 chrysalidina gradata d’orbigny, 1839 cisalveolina fraasi (gümbel, 1872) cisalveolina lehneri reichel, 1941 conicokurnubia orbitoliniformis septfontaine, 1988 conicorbitolina conica (d’archiac, 1837) conicorbitolina corbarica schroeder, 1985 conicorbitolina cuvillieri (moullade, 1972) cuneolina compressa schlagintweit, 1988 cuneolina conica d’orbigny, 1846 cuneolina ketini inan, 1988 cuneolina parva henson, 1948 cuneolina pavonia d’orbigny, 1846 cuneolina sliteri arnaud-vanneau & premoli silva, 1995 cyclogyra mahayeri (brönnimann, zaninetti & bozor­ gnia, 1972) debarina hahounerensis fourcade, raoult & vila, 1972 derventina filipescui neagu, 1968 dictyopsella kiliani munier­chalmas, 1900 dictyopselloides cuvillieri (gendrot, 1968) dicyclina schlumbergeri munier­chalmas, 1887 duostomina alta kristan­tollmann, 1960 duotaxis metula kristan, 1957 endotriadella wirtzi (koehn­zaninetti, 1968) everticyclammina praevirguliana fugagnoli, 2000 everticyclammina virguliana (koechlin, 1942) fleuryana adriatica de castro, drobne & gušić, 1994 frondicularia woodwardi howchin,1895 glomospira sp. glomospira urgoniana arnaud­vanneau, 1980 glomospira watersi loeblich, 1946 glomospirella sp. glomospirella triphonensis baud, zaninetti & bronnimann, 1971 gutnicella cayeuxi (lucas, 1935) haplophragmium sp. haplophragmoides joukowskyi charollais, brönnimann & zaninetti, 1966 haplophragmoides globosus lozo, 1944 haurania deserta henson, 1948 hellenocyclina beotica reichel, 1949 hoyenella sinensis (ho, 1959) idalina antiqua munier-chalmas & schlumberger, 1885 ‘involutina’ sp. involutina liasica (jones, 1853) karaisella uzbekistanica kurbatov, 1971 keramosphaerina tergestina stache, 1913 keramosphaerina sarda cherchi & schroeder, 1990 kilianina blancheti pfender, 1933 kilianina? rahonensis (foury & vincent, 1967) kurnubia jurassica (henson, 1948) kurnubia palastiniensis henson, 1948 kurnubia wellingsi (henson, 1948) labyrinthina mirabilis weynschenk, 1951 laffitteina mengaudi (astre, 1923) lamelliconus multispirus (oberhauser,1957) lamelliconus procerus (liebus, 1942) lepidorbitoides minor (schlumberger, 1901) lituolipora termieri (hottinger, 1967) lituosepta recoarensis cati, 1959 marzoella ficcarellii chiocchini & mancinelli, 2000 mayncina bulgarica laug, peybernès & rey, 1980 meandrospira dinarica kochansky-devidé & pantić, 1966 meandrospira favrei (charollais, brönnimann & zani­ netti, 1966) meandrospira pusila (ho, 1959) meandrovoluta asiagoensis fugagnoli, giannetti & ret­ tori, 2003 merlingina cretacea hamaoui & saint-marc, 1970 mesoendothyra croatica gušić, 1969 mesoendothyra sp. mesorbitolina lotzei schroeder, 1964 mesorbitolina oculata douglass, 1960 mesorbitolina parva douglass, 1960 mesorbitolina pervia douglass, 1960 mesorbitolina subconcava leymerie, 1878 mesorbitolina texana (roemer), 1849 minouxia lobata gendrot, 1963 mohlerina basiliensis (mohler, 1938) moncharmontia apenninica (de castro, 1966) moncharmontia compressa (de castro, 1966) montsalevia salevensis (charollais, brönnimann & zani­ netti, 1966) murciella cuvillieri fourcade, 1966 murciella renzi fleury, 1979 murgeina apula (luperto sinni, 1968) murgeina cenomana (luperto sinni, 1998) murgella lata luperto sinni, 1966 nautiloculina sp. nautiloculina broennimanni arnaud­vanneau & peyber­ nès, 1978 nautiloculina circularis (said & barakat, 1959) nautiloculina cretacea peybernès, 1976 nautiloculina oolithica mohler, 1938 appendix list of taxa 60 geologia croatica 60/1 neoendothyra reicheli reitlinger,1965 neoiraquia convexa danilova, 1963 neoiraquia insolita (decrouez & moullade, 1974) neotrocholina aptiensis (iovcheva, 1969) neotrocholina friburgensis guillaume & reichel, 1957 nezzazata conica (smout, 1956) nezzazata germanica omara & strauch, 1965 nezzazata gyra (smout, 1956) nezzazata isabellae arnaud-vanneau & sliter, 1995 nezzazata simplex omara, 1956 nezzazatinella picardi (henson, 1948) novalesia sp. novalesia angulosa (magniez, 1972) novalesia cornucopia arnaud­vanneau, 1980 novalesia distorta arnaud­vanneau, 1980 novalesia producta (magniez, 1972) nummofallotia cretacea (schlumberger, 1900) nummoloculina? regularis philippson, 1887 omphalocyclus macroporus (lamarck, 1816) orbitammina elliptica (d’archiac, 1843) orbitoides douvillei (silvestri, 1910) orbitoides hottingeri van hinte, 1966 orbitoides media (d’archiac, 1837) orbitoides tissoti (schlumberger, 1902 ) orbitolina concava (lamarck, 1816) orbitolina sefini henson, 1948 orbitolinopsis sp. orbitolinopsis aquitanica schroeder & poignant, 1964 orbitopsella ?dubari hottinger, 1967 orbitopsella praecursor (gümbel, 1872) orbitopsella primaeva (henson, 1948) ovalveolina crassa de castro, 1966 ovalveolina maccagnoae de castro, 1966 paleodictyoconus actinostoma arnaud-vanneau & schroe­ der, 1976 paleopfenderina salernitana (sartoni & crescenti, 1962) paleopfenderina trochoidea (smout & sugden, 1962) palorbitolina lenticularis (blumenbach, 1805) paracoskinolina fleuryi decrouez & moullade, 1974 paracoskinolina sunniladensis (maync, 1955) paravalvulina complicata septfontaine, 1988 parurgonina caelinensis cuvillier, foury & pignattimorano, 1968 pastrikella balcanica cherchi, radoičić & schroeder, 1976 pastrikella biplana cherchi & schroeder, 1980 peneroplis parvus de castro, 1965 peneroplis turonicus said & kenawy, 1957 pfenderella arabica redmond, 1964 pfenderina globosa foury, 1968 pilammina densa pantić, 1965 pilamminella semiplana (kochansky-devidé & pantić, 1966) planisepta compressa (hottinger, 1967) praealveolina iberica reichel, 1936 praealveolina simplex reichel, 1936 praechrysalidina sp. praechrysalidina infracretacea luperto sinni, 1979 praekurnubia crusei redmond, 1964 praeorbitolina cormyi schroeder, 1964 praeorbitolina wienandsi schroeder, 1964 praesiderolites douvillei wannier, 1983 protochrysalidina elongata luperto­sinni, 1999 protopeneroplis striata weynschenk, 1950 protopeneroplis ultragranulata (gorbatchik, 1971) pseudocyclammina liassica hottinger, 1967 pseudocyclammina lituus (yokoyama, 1890) pseudocyclammina massiliensis maync, 1959 pseudocyclammina maynci hottinger, 1967 pseudocyclammina rugosa (d’orbigny, 1850 pseudocyclammina sphaeroidea gendrot, 1968 pseudodictyopsella jurassica septfontaine & de matos, 1998 pseudoeggerella elongata septfontaine, 1988 pseudolituonella conica luperto sinni & masse, 1993 pseudolituonella marie gendrot,1968 pseudolituonella reicheli marie, 1955 pseudonummoloculina sp. pseudonummoloculina aurigerica calvez, 1988 pseudonummoloculina heimi (bonet, 1956) pseudorhapydionina dubia (de castro, 1965) pseudorhapydionina laurinensis (de castro, 1965) pseudorhapydionina mediterranea (de castro, 1974) pseudorhipidionina casertana (de castro, 1965) pseudorhipidionina murgeana (crescenti, 1964) pseudosiderolites vidali (douville, 1907) raadshovenia salentina (papetti & tedeschi, 1965) rectodictyoconus giganteus schroeder, 1964 redmondoides lugeoni (septfontaine, 1977) reticulinella fleuryi cvetko, gušić & schroeder, 1997 reticulinella reicheli cuvillier, bonnefous, hamaoui & tixier, 1969 rhapydionina liburnica (stache, 1889) rotalia mesogeensis tronchetti, 1993 rotorbinella scarsellai torre, 1966 rumanoloculina robusta (neagu, 1968) sabaudia auruncensis (chiocchini & di napoli alliata, 1966) sabaudia briacensis arnaud­vanneau, 1980 sabaudia capitata arnaud­vanneau, 1980 sabaudia dinapolii chiocchini, 1984 sabaudia minuta (hofker, 1965) satorina apuliensis fuorcade & chorowicz, 1980 satorina mesojurassica (maync, 1972) scandonea phoenissa saint­marc, 1974 scandonea pumila saint­marc, 1974 scandonea samnitica de castro, 1971 sellialveolina viallii colalongo, 1963 siderolites calcitrapoides lamarck, 1801 simplorbitolina brönnimanni (decrouez & moullade, 1974) siphovalvulina colomi bou dagher­fadel, rose, bosence & lord, 2001 siphovalvulina gibraltarensis bou dagher­fadel, rose, bosence & lord, 2001 siphovalvulina variabilis septfontaine, 1988 spiraloconulus giganteus cherchi & schroeder, 1982 spiraloconulus perconigi (allemann & schroeder,1972) spirolina cretacea tronchetti & grosheny, 1993 spiroloculina cretacea reuss, 1854 spiroloculina robusta brady, 1884 stensiöina surrentina torre, 1966 timidonella sarda bassoullet, chabrier & fourcade, 1974 triasina hantkeni majzon, 1954 trochamminoides coronus loeblich & tappan, 1946 trocholina sp. trocholina acuta oberhauser, 1964 trocholina alpina (leupold, 1935) trocholina arabica henson, 1949 trocholina crassa kristan, 1957 trocholina delphinensis arnaud-vanneau, boisseau & darsac, 1988 trocholina elongata (leupold, 1935) trocholina molesta gorbatchik, 1959 trocholina gigantea pelissie & peybernès, 1983 trocholina odukpaniensis dessauvagie, 1968 trocholina sagittaria arnaud-vanneau, boisseau & dar­ sac, 1988 trochospira avnimelechi hamaoui & saint-marc, 1970 turrispirillina minima pantić, 1967 turriglomina mesotriassica (koehn­zaninetti, 1968) ‘valdanchella’ dercourti decrouez & moullade, 1974 vercorsella arenata arnaud­vanneau, 1980 geol. c roat. soil 7 is 3 figs. 3 tabs. zagreb 1997 compositional zoning in amphibole from amphibole bearing parageneses of west psunj (croatia): evidence for progressive metamorphism? orazen balen, vladimir bermanec and vera marcl key words: amphibo le, amphibolite , geot hcrmomc­ try, gcobaromctry, pslinj . croatia. abstract amphibo le bc(u"ing paragcncscs from the wes tern par i of ml psunj (croatia) record evidence of prograding metamorphism. opti­ cal and mic roprobe anal yses, together with thcrm obarornetric evalua­ ti ons 0 11 amphibole beari ng paragcncscs, show a zonal ion wit h si­ and mg-conccll lralions decreas ing from core to ri m al ong wilh increasi ng a i-, n (i-. and ti -contenl. changes in the chem ical compo­ si tion of am phibo le g rai ns ;i f e interpreted thro ugh coupled su bstiw­ lions. and reac ti ons w ith co-ex isting minerals duri ng an increase in mctamorphic conditions from greenschi st 10 amphibo lite facies . the change in p-t conditions recorded in the growth of amphibole grains (gcncral prograding patt crn) togcthcr with ch:mgcs in thc modal com­ positions in rclated paragcncscs could bc intcrprcted in a model of a subduction zone. 1. introduction minerals or the amphibole group are common rock­ formin g minera ls in metamorphic rocks. they are sta­ ble over a wide range of pressu res and temperatures i.e. in various grades of metamorphism. the associa tions of amphibole with plagioclase, epidote, clinozoisite, chlo­ rite, sphene, e tc. arc common in metamorphosed mafic rocks of the grccnschi sl facics, epidote-amp hibol ite facies and amphibol ite facies. many authors recognize similar assemblages, usual­ ly called "commo n assemblages" (lair d & albee, 198 1) for mafi c schis ts of greenschist to amphibo lite fac ies all over the world. in contrast to mafic schi sts , in metape litic rocks eve n small in cremental changes in pressure and temperature can be dete rmined by the sim­ ple recognition of key minerals. changes of metamor­ phic grade in mafic schists are less obviolls. dillcrenccs between metamorphic facies may be recorded through continuous reac tions wh ich produce " fin gerp rint s" in the chemi ca l con1pos it ion of phases and the modal composition of minera ls. these, less obvious changes may be follo wed through changes in opti cal properties and the information recorded in the zone o f" growth. in uni ve rsi ty of zagreb, r acujty o f scicnces, department of geology, institu tc for m iner<lj ogy and pctrology, horvatov<lc bb. hr-l0000 zagrcb, croatia. general the appearance or disappearance of phases (i.e. first appearance of hornblende in epidote-amphiboli te) a re only revealed when great changes in p-t conditions occur and small cha nges of p-t cond itio ns is easy to overlook, especially in the field. the assemblage stabl e in the greenschi st zone con­ sists of albite + epidote + chlorite + acti nolite + qu<:ll"tz + sph ene (temperatu re below 370°c). tn the trans ition zone an assemblage appears wh ich includes periste rite pairs + epidote + chlorite + ca-amphibole (usua lly both ac tinolite and hornbl ende) + quartz + sphene and the temperature varies be tween 370-420°c. the amph ibo­ li te facies is characterized by ca-plagioclase (a n2o.50) + cn-amphibole (usually homblende) + chl orite + sphene + il menite (maruyama et ai. , 1982). geologic cv idence sugges ts that the transition from the greenschi st to the epidot e-amphibo li te fa c ies and from the epidote-amphibolite to amphibolite fac ies may represent a p-t fi e ld in which a number of the c ritical equi li brium curves are c losely spaced and inte rsect each other (apted & llou , 1983). therefore the recogn i­ tion of p-t condi tions in maf"ie schists is a difficult task but in favorable circumstances oscillations of metamor­ phism could be recorded and the quant ita tive value of mctamorphic variablcs cou ld be approximatcd. petrolog ical study of the ultramafic rocks loge ther with known data from associated amphibolitcs in the area of the slavonian mountains suggests that the inves­ tigated rocks belong to an ophiolite com plex (pamic & marci, 1990; pam ic & lanphere, 199 1) the purpose of this study is to de termine the mi neral asscmblages that coexist in equilib ri um, and to es timate (th rough chemical data of" the amph iboles) the li mits of tcmperature and pressure dur ing metamorphism of the amphibole-bearing rocks of wcstern psllnj. thc growth of amphibole under changing p-t condi tions lllay serve as an indi cator of the geotectonic evolut ion of thc inves­ tigated area. 2. historical review the re arc numerou s pape rs published on th e c rys­ tal line rocks from the slavonian mountains (for a com ­ prehens ive li s t of references see pam ie & lan­ pher e, 1991). kispati c (1 892) produ ced the first petrograph ic and geologic data for various metamorphic geologia croatica 501l o·~ _____ ~,5 km 0dd[sge] fig. i generalized geological map of mt. psunj from pamle & lan­ phere (1991). legend: 0 study area; i) tertiary and quaternary sediments; 2) tertiary volcanic rocks; 3) mesozo ic sediments; 4) metamorphic complex with meta­ basites; 5) metamorphic complex without metabasites; 6) migma­ tites; 7) s-type granitoids; 8) amphibolite facies; 9) greenschist facies; 10) amphibolite interlay­ ers; ii) i-type granites; 12) coll­ tactlinc;13) horizontal fault; 14) norma! fault; 15) reverse fault; 16) unconformity; 17) isoclinal folds; 18) foliatioll. 6 7 8 9 10 ii ,~, ]~ ]5 16 rocks and indicated the importance of index minerals and assemblages. marci (1965) and tajder (1969) focused their altention on the western part of mt. psunj and on the mineralogical composition of amphibole­ bearing rocks. recently pamic & marct (1990) and pamic & lanphere (1991) examined the amphibo­ lites petrographically and showed that the amphibolite of the slavonian mountains is regular member of the hercynian progressive metamorphic complex. the chemical composition of the amphibolitic rocks corre­ lates with oceanic tholeiitc. nevertheless, thc geotec­ tonic setting is not reliably determined. 3. study area the study area is delimited by the creeks rasaska and jezeriea 10 the south, sumetljica to the north, bre­ zovo polje peak in the east, and ihe granite body of omanovac to the west (fig. 1). amphibolite and amphibole schists of west psunj occur as lenses up to 10-20 m in size. there arc also occurrences of small bodies of metagabbro in the study area. the investigated rocks (amphibolite, amphibole schist, metagabbro) occur in discordant position to the surrounding rocks (granite, sediments), and are proba­ bly precambrian in age (jamicic et ai., 1989). later intrusion of the granite body resulted in retrograde altcration of the amphibole bearing rocks. -#%17 "18 4. materials and methods the mineral parageneses of amphibole bearing schists, metagabbro and amphibolite were examined by standard polarizing microscope and detailed optical measurements were made using a carl zeiss jcna microscope equipped with a five axes universal stage and conoscopic illumination. selected grains werc chcmically analyzed by elec­ iron microprobe at the univers ity of bern. the electron microprobe used was a cameca sx 50 instrument equipped with wds spectrometers with lif, pet and tap diffraction crystals. a beam current of 20 na, accelerating voltage 15 ky, peak counting 20 sec, and beam diameter less than 1 ~m were the operating coil­ ditions. synthetic standards used included fayalite (fe), spinel (mg), tephroite (mn), ilmenite (ti), eskolaite (cr) together with natural standards: orthochlase (si, k), albite (na), anorthite (ca, ai). instrument control and on-line data reduction were performed using the cameca version of the pap procedure (pouci-iou & pichoir. 1984). the amphibole formulae were generated with the minfile software (afifi & essene, 1988) on the basis of 230 and 13 cations + ca + na + k. 1l:l icll, bermanec & r\'1:1rci: compositional zoning in amphibole from amphibole bearing paragencscs ... s. results 5.1. petrography four rock types we re recognized in the amphibole bearin g rocks of western mi. psunj on the bas is of mic roscopi c study , mine ral content and tex tural fea­ tures, and are listed as follows: a) e pidote-amphibole schi st: amphibole (act inol ite ancl hornblende), epidote, qua­ rt z, oli goclase, albite ± ilmenite, sphene, chlorite; b) amphibolite: amphibo le (hornblende), oligoclase ± cl inozoisitc, chlorite, ilme nite , sphene , quartz; c) metagabbro: amphibo le (hornbl e nd e), oligoclase, clinozo is itc, ilme nite, sphene ± e pidote, chlorite. cli nopyroxene, quartz; d) "granitized" amphibo lite: amphibole (hornb le nde) , oligoclase, c linozo isite, biotite, ilmcn ite , sphene ± quartz, e pidote, micro­ c line. thc mine rals are lis ted in order of abundance. some minerals (c hlorite, c linozois ite, ... ) which are commo n in the rock types arc produc ts of late r retro­ grade me tamorphism and do not represent an equi li bri­ um state with the other mine rals. also, clinopyroxene­ amphibole-ch lorite +clinozoisite alterations imply a ret­ rog rade trend. these re trograde changes are allribut ed to c hanges of the metamorphic conditions during intru­ sion o f the granite body. amphibole amphibole occurs as xenoblasts in all the paragenc­ ses. in asscmblage a it a lso occui's as needle like aggre­ gat es with weak green-ye llow pleochroi sm. during growth, amphibole replaced pyroxene and encompassed o the r mine ral grains (plagioclase, ilme nitc, sphe ne). within thc cracks ins ide the amph ibol e grains aggre­ ga tes o r chlorite and cl inozoisi te were fofmed. amphi­ bo les in epidote-amphibo le schists of the ne ighbouring g ranit e body often show a lteration to biotit e. this is c harac ter ized by the changc rrom a grcen coloured amphibole at on e e nd or a grain toward th e brown colour or biotite at the o the r end of the same grain (in sections parallc llo the c-axis or amphibole). mcasurements or the optical parame ters of selected gra in s of amphibol e indi cated s ix different types of amphibole: a) needle like actinolit e with a maximum ex tinc tion angle z"c = 12° and optical axial angle 2v = _74°; pale pleochroi sm: x = y = yel low , z = green. it was observed in type a assemblage. b) hornblende with a maximum extinction angle z"c;;;; 19° and optical axial angle 2v = _64°; pleochroi sm: x = yellow, y = green , z = bluish-green, observed in type a and b assemblages. c) hornble nde with a maximum extinction angle zac ;;;; 16° and optical axial angle 2v ;;;; _72°; pleochroism: x ;;;; yellow, y = green, z = dark green, observed in type c assemblage. d) hornblende with maximum ex tinction angle z"c = 30° and optical axial angle 2v ;;;; +87°; pleochroism: x ;;;; yellow, y ;;;; grecn, z = dark green, observed in type c assemblage. e) hornble nde with maxirnum ex linction angle zae ;;;; 18° and optical axial angle 2v = _89°; pleochroism: x = yellow, y = green, z ;;;; da rk green, observed in type c assemblage. f) hornbl ende with maximum ex tinc tion angle zac = go and opt ical axial angle 2v = -85°; pleochroism: x ;;;; brown, y ;;;; yel lowish-green, z = green, obscrved in type d assemblage. plagioclase (oligoc lase) plagioclase occurs as hipicliomorphic e longated grains ancl alot riomorphic cquidimensional grains. usu­ ally . the hipidiomorphic grains display pol ysyn the tic twin lamc llae according to a lbite law b in ;;;; -1(010). metamorphic processes caused inte nsive sericitization and saussuriti za lion. the miche l-levy method and u­ stage measurements using the pedo rov method de te r­ mined the plagioclase as oligoclase with a compositi on or an 26-30 mol. %. oligocl ase appears in all asse rl1 blages , albite and mie roc linc albite occurs as fre sh xenob las ts, obvious ly as a lale mine ral in the assemblage. it occurs in assemblage a. microeline is observed in the type d assemblage and is a product of metasomatic reactions caused by the lat ­ er intrusion of the granite body. epidote epidote is common in type a assemblage and a minor com pone nt in both c and d assembl ages. it appears as irregular, weakly pleochroic grains, pale ye l­ low to yellow colors; 2v = -75° (pistaeite) and is ofte n associated with needle like actinolite. clinozoisi te c linozois ite appears as irregular grains, which origi­ nat ed rrom primary basic plagioe lases; 2v = +85°. it occurs in the b, c and 0 asscmblages . quartz quartz is present in all assemblage types and often shows evidence o f cataclastic processes. ~ ~ :::. ~ o ~ :3 v; g:3' :3 ~ -j (") cjl (') ...., -en 0 0.. & ;;i' v; -, 0(") -, i:: "0 '< ,..... cjl co -::r' tol < -j tol ~ ~, ~ g"0 'j} 0 ~ ::!, 'j} (") (") => ~~3'g2 ~p(1)5i''''': 2: 2. ~ 0. :3 (") _, (d 0 to) (")=>e::'""!':o~ c52~u:3 ::: 0 '< tol 0-, 0 ...., ;::::, (') ~, >-; ~ (") on:: (1) :3 0". ;:j ::j -, 1./l5 u (1)=> ~ 0.. ::r' t.) ~ < _. . (1) 0 g 0.. 20..5-0""0 ::;:: ~'c;::: n :t c -<; c n n co ul => to) ::e 0.3. g. [~~ ~ ..... ' ,..... 0 0 o -tol ::j ~ q;' ;;l 'u "" ~ ~ o " g ::!, b:j ~ -cjl (') 0 o 0" = ~ 0 -_a." ;,::, in n 0 8 ...., ~ ...., .g re ~ ~ :3' e ri g 15 "v '< (3 ~ " ~ -< -<d."2"0 () "0 to) tol to (') 2: ('):3 g -, >s; tj ~ 0.. §-. ::.: tol:::::, 0" ..-to 0 (/l 0",< (") 0; => a. n 0; ~ ~ " 3 v0; "" " !:" => ~ 20 ;:j (') ::r' cto. ;; i:: g oq (') :=: " " ·0' ::l ~ ~ ~ ~ => 2 g ~ ~ " -::, ::r' " " vs"" -" '" 3 " " ~ " ~ ~ " " ~ '" !". 3 0 " => => ;:;' <3 ~ 'u :t " => " => " " ~ ~ " 3 , &:; :3 a. -. 0' a > 'u "0 " cjl ...., (") _. 0 0 g-o-::! . " -;:::< 0.. :3' _, tol (rq (/l 5i -t o. 0 g:;.o s:; in'"'£ < . " "0 co 0.. ~ 2_, 0 (1) => ~ ~ .... (') ~ ~ ~ :3 (') ::: n ~ no tol d c ::­ ~ _ 0 i./l 0.. ::j r? ci'" i./l ;:j 0 (") 0" (") 0 s" ::r' :3 0::; :: 0-o ~ ..... ' • (") ::l " " a. ~ _. ~ n < " -. a.:;' oxides a1 si02 45.71 (1.43) ti02 1.09 (0.32) ai20 3 7.31 (097) fe 2 0 3 ' 3.27 (0.39) feo 15.39 (0.76) mno 0.42 (0.04) mgo 10.12 (0.78) cao 11.85 (0.16) na20 0.91 0.13) kp 0.71 (0.18) hp· 1.98 (0.02) sum 98.75 (0.62) #si 'v 6.91 #ai 'v 1.09 t site 8.00 #alv 1 0.22 #fe3+ 0.37 #ti 0.12 #mg 2.28 #fe2+ 1.95 #mn 0.05 m 1,2,3 5.00 #ca 1.92 #na 0.08 m4 site 2.00 #na 0.19 #k 0.14 a site 0.33 #0 22 #oh 2 no anal. 9 g ~~§.[~~~~~.: ~~2,~ ~ §~::i + ;:. n ~ ~ :::::. :::l :::l :::. r.l as' w so g ~~~ 3 g or. 00 , "" a2 50.84 0.04 2.34 1.38 16.40 0.25 11.75 12.29 0.24 0.11 1.99 97.62 7.68 0.32 8.00 0.09 0.16 0.00 2.64 2.07 0.03 5.00 1.99 0.01 2.00 0.06 0.02 0.08 22 2 81 c1 c2 c3 44.54 (0.33) 42.96 (0.74) 46.74 46.12 (0.24) 0.95 (0.04) 2.73 (0.46) 1.86 0.95 (0.14 10.32 (0.28) 11.53 (1 .02) 9.19 8.99 (0.19) 4.41 (0.22) 6.51 (1.97) 2.49 3.30 (0.50) 12.69 (0.16) 8.45 (1.74) 9.54 12.16 (0.40) 0.29 (0.03) 0.21 (0.03) 0.27 0.22 (0.03) 10.90 (0.14) 11.70 (0.44) 13.66 11.79 (0.16) 12.02 (0.12) 10.93 (0.47) 12.27 12.020.10) 1.44 (0.08) 1.61 (0.29) 1.00 1.05 (0.02) 0.47 (0.06) 0.49 (0.14) 0.27 0.47 (0.02) 2.02 (0.01) 2.03 (0.00) 2.06 2.03 (0.00) 100.05 (0.59) 9915 (0.07) 99.35 99.11 (0.17) 6.59 6.33 6.80 6.83 1.41 1.67 1.20 1.1 7 8.00 8.00 8.00 8.00 0.39 0.34 0.37 0.39 0.49 0.72 0.27 0.37 0.11 0.30 0.20 0.11 2040 2.57 2.96 2.60 1.57 1.04 1.1 6 1.50 0.04 0.03 0.03 0.03 5.00 5.00 5.00 5.00 1.91 1.72 1.91 1.90 0.09 0.28 0.09 0.10 2.00 2.00 2.00 2.00 0.32 0.18 0.19 0.21 0.09 0.09 0.05 0.09 0041 0.27 0.24 0.30 22 22 22 22 2 2 2 2 5 6 5 c4 d1 49.33 (0.57) 47.52 (0.80) 0.66 (0.05) 0.98 (0.22) 6.44 (0.19) 7.77 (0.54) 4.34 (0.58) 3.55 (0.74) 10.88 (0.55) 13.17 (0.85) 0.23 (0.04) 0.40 (0.09) 13.28 (0.29) 11.59 (0.60) 12.02 (0.19) 11 .88 (0.20) 0.81 (0.09) 1.10 (0.09) 0.24 (0.03) 0.44 (0.08) 2.07( 0.01) 2.04 (0.02) 100.30 (0 .71 ) 100.44 (0.62) 7.14 6.97 0.86 1.03 8.00 8.00 0.24 0.30 0.47 0.39 0.07 0.10 2.87 2.53 1.32 1.62 0.03 0.05 5.00 5.00 1.86 1.86 0.14 0.14 2.00 2.00 0.09 0.18 0.05 0.08 0.14 0.26 22 22 2 2 4 8 d2 45.63 (0.71) 0.55 (0.08) 14.43 (0.77) 3.70 (0.86) 9.51 (1.18) 0.22 (0 .08) 11.12 (0.58) 10.51 (0.44) 2.20 (0 .24) 0.51 (0.07) 2.09 (0.01) 100.47 (0.39) 6.55 1.45 8.00 0.99 0040 0.06 2.38 1.14 0.03 5.00 1.62 0.38 2.00 0.23 0.09 0.32 22 2 10 o o 8 0~~. (") g [j" .~ s 13;l lcn.l3cnnall<.:c &. marci: compositional zoning in amphibole from amphibole i3carin!! 1';"'ilgcllcscs ... ii 1 • tremolite magnesio-hornblende tschermak.ite 0.9 • a type 0_8 £' • " ll • b type + .t. c type en • :2 • d type • '. '§; • . . • • t . • • 0.7 • • :2 • • • • • .t. ....... • • .. ."\. , • • .. ii. ii. .... " • •• 0.6 . • . • " " ". " "." " 0.5 8 7.5 7 6.' 6 fig. 2 class ification o f calcic amphibole (modifi ed arter leake, 1978: hawthor­ ne, 1983: rock & leake, 1984 according to internal ional mineral ogical association comm iss ion on new minera ls and m i neral names ( im a cn fvimn) nom enclature of a mphiboles (drart 5, t995)) . diagram parameters: cae ;::: 1.50; (na + k)a < 0.50; ca,\ < 0.50. si (apiu) the cleavage cracks of amphibole as alte rati ons and as indi vidual grains in the matrix. additional minerals garnet occurs as grains in type d assemblage. cal ­ c ite is a secondary mineral. apatite and zircon are very rare, and are obse rved as solid inclu sions in both amphibole and plagioclase. 5.2. mineral chemistry amphibole a represent31ive chemical analys is of selected amphibo le sampl es and their chem ical formulae are presented in tabl e i. the fe2 + and fe3 + content s were es tim ated fro m the total o f cations (exc luding na, k anel ca) normalized to 13. assumption of normali zing cations to 13 + ca + na + k excl udes mn , fe2 + and mg from the m .. site in the formulae (rob inson el ai., 1982) and produces fairly reasonable es timates or feo and fe20 3• this normaliza­ tion procedure is also favored by the international min­ era logical assoc iation (lma) amphibole nomenclature scheme (l ea ke, 1978; hawthorne, 1983 ; rock & leake, 1984). in this work, the orig inal c lassifica­ tion scheme aft er leake was modificd according to the commi ss ion on new minerals and minera l names (cnmmn ima) nom enclalure of amphiboles (drafl 5 , 1995). modifi cation s are basically chan ges in the values of diagram parameters which result in the disap­ pea rance of the fie lds o f tcherm ak itic and ae tinol ilic hornblende. all the analyzed amphi bole grains have (ca+na)n> 1.0 and nau < 0.5, so they arc calc ic amphiboles. a graphical presentation o r thc analyses is given in fig. 2. further subdivi sion of (he amphibol cs 011 the basis of the plot mgj(mg+fe2+) against si shows that most of the anal yzed samples occur in the fi e ld o f magnesio­ hornbl ende (iype a, b and d). amph ibo les of c iype show a hi gh degree o f variabil ity and projcct into the fi e lds o f tschermakite and magnesio-hornble nde. the actinolite of type a project into thc " tremolite" fi e ld. the te trahedra l va lues o f s i are restri cted be tween 6. 33 and 7.14 apfu with the exception of ac tin o lite (7.68 ap fu s i). the octahedral aluminum ranges between 0.22 and 0. 39 apfu wilh ihe exeeplioll of aclinolile (0.99 ). according 10 robinson el a l. (1982), ihe 10lal al v, shou ld not exceed 1.4 and averages around 0.4 ap fu. titanium in the octahedral sites varies from 0.06 to 0.30 apfu (it is not detccted in actino lite). the contents of mg and fe2 + in the m t.2.~ sit es are compl ementary because these arc two essent ial cations in the amphiboles. variati on of these two cations in the amphiboles reflect s the chemi stry of their host rocks. mn is a minor clement in the m 1.2.3 s ite. calc ium is concentra ted in the m4 s ite and varies from 1.62 101.99 aprl!. sodium parlially fill s ihe m, sil e to 2.00 apfu and the remaining na with k is ass ig ned to the a site. t he total na in both s ites in amphibo les from type d assemblage can reach 0.62 apfu whi ch is an elevat ed concentrat ion in compari son with other amphiboles . potass ium is res tric ted to the a sile from 0.02 10 0. 14 , averaged 0.08 apfu. 5.3. thermobarometric evaluat10n or: met amorphism recent studics indicate rul es which govern changes in the composition or amphibol es and plagiocl ases as a response to progressivc alteration of the metamorphic collciiliolls ( hollan d & r1c hardso n, 1979; spear, 1980, 1981a, b; hy nes, 1982; ma ruya ­ ma el ai., 1982, 1983; blu ndy & holla nd, 1990). amphibo les of assemblage d have th e larges t amount s of na, k and ai. in amphiboles of assemblage c conccntrations of ti are hi gher but this is probabl y due to the hi gh contcnt of ti in the prolho lite (gabbro). 12 trc spear blundy & holland (1980) (1990) sample 26% an 30% an a1 500 666 675 a2 350 478 484 b1 500 730 740 c1 530 783 795 c2 500 688 697 c3 490 682 691 c4 510 618 626 d1 510 654 662 d2 530 738 749 table 2 temperature of metamorphosis on the basis of the spear (1980) and blundy & holland (1990) geothermometcrs. a high content of ti is also found in type d amphi­ boles, the lowest si contents are found in amphiboles of lype c and d assemblages. in amphiboles from a assemblage the distribution ofti, na, k, ai and s i have an opposi te tfend to those amphiboles of assemblage d. amphibo les from assemblage a have the lowest con­ tent or ti, na, k and al and largest amounts of si. therefore it can be stated that the highest tempera­ tures occurred during growth of amphiboles in assem­ blage d, were lower in assemblages band c and lowest in the assemblage a. equilibrium on the scale of the hand-specimen is assumed between obse rved amphibole-plagioclase pairs. because plagioclase grains were not measured by microprobe the whole range of plagioclase composi­ tions obtained by optical measurements were used for geothermobarometry calculations. tcmperatures of metamorphism were outl ined with graphical solulion on the basis of spear's (1980) geothcrmometer, and calculated from the equation from the b lundy & holland (1990) geolhennometer, with an assumed pressure of 5 kbars (5.108 pa) and pla­ gioclase compos ition range betwcen 26% an and 30% an (determined by u-stage measurcments). the results arc shown in table 2. there arc differences between the results obtained using these two approaches. the "semiquantitative" numerica l solut ion (because the chemistry of plagio­ clase had not been determined by electron microprobe) obtained from the blundy & holland (1990) geothermometer shows a simi lar trend in temperature d istribut ion for all amphibole bearing parageneses, but the values seem to be too high for the observed parage­ neses. this geothennomcter is vely sensitive fo r cation content and due to thc "semiquantitative approach", a possib le discquilibrium (amp hibole rim plagioclase core), and metasomatic effects from intrusion of granite body, exact va lues of the thermometric evaluation should not be accepted. geologia croatica 50/1 temperatures obtained on the basis of the diagram proposed by pl yusnina ( 1982) arc in the range of 520-550 c for the non-actinoli te assemblages (b, c and d). geothennometry evaluat ions are in agreement wi th the spear (1980) empirical geothermometer. estjmation of pressures was performed with the aid of a diagram proposed by plyusnina (1982) . t he calibration of this diagram produced a wide range of pressures (depend ing on the ai content in the amph i­ bole) where amphiboles occur in the range from 2 kbars to 5 kbars (2 to 5.108 pal wilh the exception of one specimen in assemblage d. this specimen has a p value of? kbars (7.108 pal. according to temperatures stated in the introduction (maruy ama et ai., 1982) amphiboles from assem­ blage a belong to the greenschist facies, while amphi­ boles from assemblages b, c and d are of the amphibo­ lite facies. zonal growth of amphibole grains is a result of mul­ tiple periods of mineral growth. the cores appear to be re li cs, preserved because of incomp lctc cquilibrium. assuming that the cores grew before the rims, amphi­ boles can be used as an relative time indicator. more­ over, the distinct compositions of core and rim, indicate different metamorphic conditions. each growth event can be characterized by a different metamorphic grade. partial reequi libration wi ll prevent the de termination of the core composition at the peak of metamorphism. it is also very probab le that the mineral assemblage was slightly dirl"crenl when the core crystall ized. or course, only larger grains have diffe rent cores from rims, because the core in (he sma ller grains was completely consumed. elements necessary to make new rims come from alteration of other phases (change in modal and chemical compositions). informat ion about the metamorphic conditions dur­ ing crystal growth of amphiboles from type c assem­ blage are recorded in fig. 3. as minerals are buffered by the whole assemblage, the composition of individual minerals can be mutually compared, and variations in mineral chemistry can be related to differences in meta­ morphic grade or facies series rather than bulk rock composition. profiles show the differences in the d istribution of cations. these differences are due to changes in meta­ morphic conditions during the mineral growth. the cores of amphiboles have higher amounts of si and mg and lower amounts of ai, ti, na, k and fe than the rim of same grain . increas ing of fe, na, fc/mg ratio and decreasing of mg and si from cores to rims of the grains also indicates ris ing pressure. accord ing to spear (l981b) this sugges ts that the temperaturc increased dur ing mineral growth. therefore we can suggest conditions of relative pro­ grading metamorphism. co-existing amphiboles have (naa +k) ,; 0.25, nam, ,; 0.2, 0.6'; ai 'v ,; 1.2 and 0.6'; (alvl+fc3++ t i) ,; 1.2 in low-pressure samples. alternatively co-exist ing amphi­ bole have 0.2'; (naa+k)'; 0.5, 0.2'; na'h'; 0.5, 1.2'; balcn, bcrmancc & marci: cumposilioll;11 zoning in amphibolc from amphiboic l3carillg paragcncscs ... ij rim core rim • .00 --0# si iv si02 46.74 49.70 50.19 48.99 46.61 7.50 ti02 0.86 0.54 0.49 0.70 0.95 7,1)(1 alz0 3 8.68 5.80 5.41 6.28 8.51 , fez0 3 2.33 2.67 2.41 2.99 4.00 ~ 6,50 feo 2.92 11.63 11.06 11.50 11.84 ~ '.00 mno 0.20 0.27 0.29 0.19 0.22 mgo 11 .82 13.54 13.89 13.22 11.98 5,50 cao 12.08 12.21 12.11 12.12 11.94 '.00 nazo 1.08 0.81 0.71 0.71 1.06 rim core rim kp 0.47 0.21 0.17 0.28 0.42 hp 2.03 2.05 2.05 2.04 2.04 3,50 -0# aiiv total 99.21 99.43 98.78 99.02 99.57 '00 --0-# fe~' -6# mg #si iv 6.91 7.25 7.34 7.18 6.86 , #ai iv 1.09 0.75 0.66 0.82 1.14 ~ <.50 rn t pos. 8.00 8.00 8.00 8.00 ~ ' .00 8.00 , ~ ~ #ai vi 0.42 0.25 0.27 0.27 0.34 ~1.50 _ #fe3+ 0.26 0.29 0.26 0.33 0.44 " '.00 #ti 0.10 0.06 0.05 0.08 0.11 #mg 2.60 2.95 3.03 2.89 2.63 0.00 rim core rim #fe2+ 1.60 1.42 1.35 1.41 1.46 #mn 0.03 0.03 0.04 0.02 0.03 m i ,2 ,3 5.00 5.00 5.00 5.00 5.00 o.~ -<># ti --0-# na a #ca 1.91 1.91 1.90 1.90 1.88 0 .25 -& #k #na 0.09 0.09 0.10 0.10 0.12 ~ 0.20 m4 pos 2.00 2.00 2.00 2.00 2.00 , 1i • ;; 0.15 #na 0.22 0.14 0.10 0.11 0.19 .. #k 0.09 0.04 0.03 0.05 0.08 ~ 0.10 a pos. 0.31 0.18 0.13 0.16 0.26 ~ 0.05 #0 22.00 22.00 22.00 22.00 22.00 0.00 #oh 2.00 2 .00 2.00 2.00 2.00 rim core rim fig. 3 comparison of chcmical compositions in core and rims from lypc c amphibolc. aiiv ~ 1.8 and 1.2 ~ (alvl+fej++ti) :::; 1.8 in mcdi um ­ pressure samples (laird & albee, 198j). in the west psunj region there are low-pressure amphiboles but samples of types c and 0 were probably stabilized at medium-pressure. accurate estimation of pressure is difficult and the broad conclusion of pressure estimates is that pressures in parageneses from b, c and 0 assemblages were higher (i n respective order) than in assemblage a. 6, discussion and conclusions investigated amph iboles can bc regarded as a solid solution consisting of tremolitc pargasite edcnitc tchermakite (ca,mg,sipn (oh),), (naca2mg,aisi"ai,on (oh)2)' (naca,mg,si7aio,,(oh)2)' and (ca2mg,ai,si"a l,on ( 0 h),) components. the trenlolite-actinolitc molecule is stable in thc grecnsch ist field while the tschermakite molecule is stable in the amphibolite facics, and the edcnitc mol­ ecule in the epidote-amphibolite facies (holland & richardson, 1979). recalculations of the amphi­ bole compositions to the mole fract ions (currie, 1991) shows that the tremolite-actinolite and edenite mole fractions prevail in amphiboles of assemblage a, while tschermakite and edenite are dominant in the oth­ er assemblages (table 3). amphiboles from assemblage a belong to the greenschist facies or to the albite-epidotc zone. with a rise of p-t condit ions, the tschermakite mole-fractions also increase, so the amphiboles of assemb lages b, c and d belong to the transition zone and lower amphibo­ lite facies. in this rangc of p-t conditions a change in the com­ posi tion of amphiboles leads to thc transition from acti­ nolite into hornblende through coupled substitutions: o (a) + si(lv) = na(a) + ai(iv) eden ite substitution mg(vi) + si(iv) = ai(vi) + ai(iv) tsehermakite sub­ stitution 14 a1 a2 b1 c1 c2 hornblende 51.3 23 .3 9.1 46.5 barroisite 7.5 1.2 9.0 15 .6 8.1 tchermakite 8.2 40.6 55.2 20.0 edenite 32.8 7.9 41.1 18.1 25.0 gedrite 0.3 0.2 tara mite 10.8 tremolite 37.6 actinolite 29.5 wh ich togethe r gave [j (a) + m g(y i) + 2si(ly) = na(a) + a i(yi) + 2ai(iv) pargas ilc substitution and numerous other reactions with co-existing minerals. during reaction s the re arc changes in the c hemical compositions of mine ra ls (continuous reac tions) and in the modal composition of minera ls, resulting in forma­ tion o f ne w m ine rals and the de trime nt or expi rat ion of pre-exis ting mine rals (discontinuolls reactions). so, par­ a lle l wi th the transition o f act inolite into hornblende, albit e d isappears, the composition of chloritc changes ( inc reasing mg component , de trimental to the chlorite modal composit ion , and finall y disappeara nce of c hlo­ rite from the assemblage) . paralle l 10 thi s process is an increase in the ai component in epidole, detrimental of the modal compos ition and the final disappearance of e pidote. with the c hanges of modal composition of c hl ori te and cpidolc, the ai content in thc p lagioclase and the fe content in amphiboles increases . also with mo re basic plag ioc lasc the ai and na content in the amphibolcs increases. these c hanges arc di scontinuous. t he s tud ied m atc rial has cons is tc nt pe trographi c fea tures with cert ain s tructural, textural, compositional and mine ralogical vari ation s. di rfere nees be l ween the amphibolc bearing pm'ageneses of wes t pslinj are main­ ly the modal compos ition of mi ne rals, and var iat ions in the chemical compositions which have only been inves­ ti ga ted in de tail in the amphiboles . al l paragcneses have in common amphibole and plag ioclase with minor amounts of qua rt z and ilmenite or sphene. chemica l inves ti gations of the amphiboles indicate va ri ations in the features which e na bl e deduc tion of genet ic cond it ions and processes. te mpe rature of for­ mation is se t to be tween 490 an d 550'c (350°c for actillo litcs) and pressure between 2 and 5 kbars (2 and 5 ·io' pa). one specim e n (lype d) has a p va lue of 7 kbars (7' 10' pal. g eoc hemi cal in vestigat ion s (pamic & marci, 1990) suggest that there is no rad ical change in the pro­ tholite compos ition (prolholile is thol e iitic basalt) and that these me tamorphic processes can occur in the ophi­ olite zone (pam ic & lanphere, 1991 ). differences in assemblages may be a ttribut ed 10 c han ges in p-t condit ions. gt,-ologi;t cromiea 50/ 1 c3 c4 d1 d2 43.6 58.4 56.9 9.0 13.3 13.1 30.4 17.3 3.5 37. 1 30.0 13.8 26.3 24.7 7.7 tab le 3 mole frac ti ons of 9.8 amphibo le end-members 4.5 calculated with sort ware aftcr curri e ( 1991 ). changes in p-t conditions are recorded in the growth or the amphibole grain s (gene ral prograding me tamorphi sm) and c hanges in modal compositions in re lated parageneses indi cate that the st ud y area has undergone geotectonic change during ils e volution. a mode l which may expla in the c hange of conditions from greenschis t to amph ibolit e faci es as recorded in the an1phibolc of wes t psunj , may be that o f a subduc­ tion zone. howeve r to tho roughly validate thi s mode l more data are required to confirm espec ia lly the re la­ tionship between the p-t inc re ments and the lime scale. fu rtherm ore, differences between assemblage a and 0 , c and d could be explain ed by varyi ng c he mical composition or or ig inal protholi te (for instance lultitie sediments). the protholite compos ition of assemb lage a has not ye t been rel iably de te rmined. acknowledgments use or the electron mic roprobe of the uni ve rs ity of be rn by sehweitze ri sehe r nat ionalfond s (c redit 2 126579.89) is acknowledged togethcr w ith fi nanc ial sup­ por t from the croati an minis try of scie nce a nd tech­ nology (credi ts 1-09-016 and 1-09-238). the a uthors are a lso g raleful 10 prol pcle r arkai (h un gari a n academy or scie nces) and to an anony ­ mous re vi e wer for the ir improve ment s to th e manu­ script. 7. references afif i, a. & essene, ej. ( 1988): m inf il e: a mic rocomputer program cor storage a nd manipula­ tion of chemical data on mincrals.am. mine ral. , 73, 446-448. apted , m.j. & l10u, j.g. ( 1983) : phase re la tions among greenschist, epidote-amph ibolite and amphi ­ bolite in a basaltic sys le m. am. jour. sc i., a, 283, 328-354. blundy, j.d. & holland , t.j.b. ( 1990): c al c ic amphibole equilibria and a new amphibo le-plag io­ c lase geothermome tc r. cojltrib. m inerai. pe trol. , 104 , 208-224. l3a1<..:l1. i3cnnallcc & m;)rci: compos ition;)1 zoning ill amphibole from amphioole beari ng paragel1eses ... 15 currie, k.l. (1991): a simp le quantitative calcula­ tion of mol fractions of amphibole end-members.­ can. mincral., 29, 287-299. ha wti-iorne, f.e. (1983): the crystal chemistry or the amphiboles.can. mineral., 21, 173a80. i-lynes, a. (1982): a comparison of amphiboles from meclium and low pressure metabas ites.contrib. mineral. petrol., 81, 119-125. holland, tj.b. & richardson, s.w. (1979): amphibole zonation in metabasites as a guide to the evolution of metamorphic conditions.contrib. mineral. petrol., 70,143-148. jamicic, d., vragov ic, m., & mattcec, d. (1989): osnovna geoloska karta 1: 100000, t umac za list daruvar l33-95 (geology or sheet daruvar). ­ geoloski zavod zagreb (1988), say . geol. zavod beograd, ssp. kispatic, m. (1892): prilog geolozkol11 poznavanju psunja.rad jazu, 109, 124-181, zagreb. laird, j. & albee, a.l. (1981): pressure, tempera­ ture , and time indicators in mafic schist: thei r appli­ cation to reconstructing the po!ymetamorph ic histo­ ry ofvermonl.am . j. sci., 281,127-175. leake, b.e. (1978): nomenclature or amphiboles.­ mineral. mag. , 42, 533-563. marci, v. (1965): petrography of the western part of psunj mountain (in croatian).acta geologica, iv, 315-322, zagrcb. maruyama, s., l10u, j.g. & suzuki, k. (1982): the peristerite gap in low-g rade metamorphic rocks. contrib. mincral. petrol., 81, 268-276. maruyama, s., suzuki, k. & l10u, j.g. (1983): greenschist-amphiboli te transition equil ibria at low pressures.j. petrol., 24, 583-604. pamic, j. & lanphere, m. (1991): hercynian gran­ ites and metamorphic rocks from the mts. papuk, psunj, krndija and the surrounding basement of the panonian basin in siavonija (northern croatia) (in croatian).geologija, 34, 81-253, ljubljana. pamic, j. & marci, v. (1990): petrology of amphi ­ bolites from the slavonian mountains in northern croatia (in croatian). geoloski vjesnik, 43, 121 133. pl yusnina, l.p. (1982): geothermometry and geo­ barometry of plagioclase-hornblende bearing assem­ blages.contrib. mineral. petrol., 80, 140-146. pouchou, j.l. & pi choir, f. (1984) : un nouveau modele de caleul pour la microanalyse quantitative par spectrometric de rayons x.la recherche aerospatiale, 3,167-192. robinson, p., spear, r.s., schumacher, le., laird, j. , klein , e., ewans, b.w. & do­ olan, b .l. (1982): phase relations of metamor­ phic amphiboles: natural occurrences and theory.­ in: veblen, d.r. & ribe, p.h. (eels.): amphi­ boles: petrology and experimental phase relations. reviews in mineralogy, 9b, mineral soc. am., 1228. rock, n.m.s. & leake, b.e. (1984): the interna­ tional mineralogical association amphibole nomen­ clature scheme: computerization and its conse­ quences. mineral. mag., 48, 211-227. spear, f.s . (1980): nasi ~ caai exchange equilibri­ um between plagioclase and amphibole. an empiri­ cal moclel.contrib. mineral. petrol., 72, 33-4l. spear, f.s. (1981 a): amphibole-plagioclase equi li b­ ria: an empirical model 1'01' the relation albite + tremolite:::: cdcnitc + 4 quartz.contrib. mineral. petrol., 77, 355-364. spear, f.s. (198ib): an experimental study of horn­ blende stabi lity and compositional variability in amphibolite.am. jour. sci., 281, 697 -734. tajder, m. (1969): the petrogenesis of blastopor­ phyritic amphibolite in the region of omanovac in psunj (in croat ian) .acta geologica, vi, 5-16, zagreb. manuscript received july 15, 1996. revised manuscript accepted april 28, 1997. 16 geologia croaticl 50/1 zigovecki.indd �ab stra ct identifi cation of calcite and aragonite is very important for studying different fossil or recent biomineralized skeletons. a problem occurs when scanning electron microscopy is used for studying calcite and aragonite present in the same part of skeleton. the same chemical composition of these two minerals produces the same contrast on sem images. there are three possible ways to distinguish calcite and aragonite in such a mixture. (1) it is possible to recognize the crystal habits of these two minerals, if crystal faces are developed. (2) the geochemical difference can also be an important tool for distinguishing aragonite (containing large cations like sr, ba, or pb) from calcite (containing small cations like mg, mn, fe, zn, or ni). however, it is also possible that large cations remain in the calcite crystal structure after phase transformation from aragonite to calcite. (3) the third possibility for distinguishing calcite from aragonite is to use staining methods. different staining methods used for sem analyses have had varying degrees of success. suzuki et al. (1993) successfully used meigen’s staining method, but results provided by feigl’s staining method were unsatisfactory. the failure when using feigl’s staining method was caused by the erroneous application of the solutions. keywords: calcite, aragonite, morphology, geochemical difference, feigl’s staining method, sem identifi cation of biogenetic calcite and aragonite using sem � željka žigovečki gobac1, hrvoje posilović2 and vladimir bermanec1 1 department of geology, faculty of science, university of zagreb, horvatovac 95, 10000 zagreb, croatia; (zeljkaz@geol.pmf.hr) 2 department of geology, faculty of science, university of zagreb, horvatovac 102a, 10000 zagreb, croatia doi: 10.4154/gc.2009.14 geologia croaticageologia croatica 1. introduction different methods have previously been used for distinguishing a variety of carbonate minerals at different scales – from hand specimens to thin sections and micro to nanoscale mixtures. calcite and aragonite are the two most common polymorphs of calcium carbonate. they very often occur in mixtures within rocks and specially in different organism’s carbonate skeletons – either recent or fossil ones. calcite caco3 is a hexagonal mineral, point group 3–2/m, space group r3–c, with a=4.9896(2) å and c=17.0610(11) å (anthony et al., 2003). the structure of calcite was determined by bragg (1914), redetermined by sass et al. (1957) and refi ned by effenberger (1981). the customary way of describing the calcite structure is using sodium chloride structure as a starting point (bragg, 1937). if sodium chloride is set up so that a threefold axis is vertical and then compressed along the threefold axis until the edges which meet it make an angle of 101°55’ with each other, and then sodium atoms are replaced by a calcium atoms, and chlorine atoms with co3 groups (bragg, 1937), the calcite crystal structure is obtained. aragonite, caco3 is an orthorhombic mineral, point group 2/m 2/m 2/m, space group pmcn, with a=4.9611(4) å, b=7.9672(6) å and c=5.7407(4) å (anthony et al., 2003). the crystal structure of aragonite is described as calcium atoms that lie approximately in the positions of a hexagonal close-packing lattice, deformed by compression along the hexagonal axis. in such an arrangement, each co3 group lies geologia croatica 62/3 201–206 5 figs. zagreb 2009 geologia croatica 62/3geologia croatica 202 aragonite forms solid solutions with strontianite, cerusite and witherite, so, the presence of large cations like sr, pb and ba could be an indicator for distinguishing aragonite from calcite. this method is not completely accurate, because of the possible phase transformation from aragonite to calcite (šebečić & slovenec, 1990), after which large cations including sr, pb, or ba could remain in the calcite structure. if a mineral grain contains small cations (mg, fe, mn, zn, co, or ni), it is surely crystallized as calcite. staining recipes and procedures as a useful tool for calcite-aragonite differentiation were used and tested by numerous authors (feigl & leitmeier, 1933; friedman, 1959; ayan, 1965; dickson, 1966). solutions most widely considered and used as contrasting agents for the selective staining of calcite and aragonite in electron microscopy are feigl’s (schneidermann & sandberg, 1971; suzuki et al., 1993; kato et al., 2003) and meigen’s stains (suzuki et al., 1993; kato et al., 2003). feigl & leitmeier (1933) described feigl’s staining test and its mechanism is based on the different crystal structures, i.e. dissolution rates of calcite and aragonite in water. schneidermann & sandberg (1971) fi rst described the use of feigl’s solution in discrimination between cal cite and aragonite by scanning electron microscopy. suzuki et al. (1993) stained molluscan shells with feigl’s and meigen’s stains and compared results by sem, bse and eds. they reported much better results with meigen’s solution, because using feigl’s staining method they “were unable to fi nd a good, size-effect-free condition”. the main disadvantage of feigl’s staining was the coarse granular appearance of the staining precipitate. kato et al. (2003) used both staining methods for the separation of calcite and aragonite for isotopic analyses. between six calcium atoms (bragg, 1937). calcium atoms in calcite and those in aragonite are arranged in approximate cubic and hexagonal close packing, respectively. in each case co3 groups occupy a position between six calcium atoms, but there is a difference. in calcite, the co3 group is placed in a way that each oxygen touches two calcium atoms. in aragonite, each oxygen atom touches three calcium atoms (bragg, 1937). this difference in the crystal structure causes not only the different x-ray diffraction patterns, but also the various solubilities of these two polymorphs, which enables the use of several staining methods. the crystal habit of calcite is extremely variable and some of the most common habits are: prismatic, thin to thick tabular, rhombohedral, or scalenohedral (palache et al., 1951; goldschmidt, 1913b). figures 1a and 1b show the most widespread crystal habits of calcite. untwinned cry stals of aragonite are very rare. if they occur, they are usually short to long prismatic, very often needle like (palache et al., 1951, goldschmidt, 1913a). figure 1c shows the prismatic crystal habit of aragonite. crystal structure and chemistry are not the only factors affecting morphology. the chemical and physical conditions prevailing during crystal growth could also modify crystal habit (speer, 1983). during biomineralization, orthorhombic carbonates (among them aragonite) are used by different creatures to form a variety of structures to support, house and protect themselves (speer, 1983). unfortunately, organisms produce skeletons of carbonate minerals mostly with close packing crystals, so, crystal habit in most cases cannot be observed in biomineralized skeletons. the crystal structure of calcite allows a wide range of compositional variation and different solid solutions, which include many divalent cations (like mn, fe, mg, zn, co, or ni). fi gu re 1: (a) rhombohedral crystal habit of calcite. (b) scalenohedral crystal habit of calcite. (c) prismatic crystal habit of aragonite twins. a b c žigovečki et al.: identifi cation of biogenetic calcite and aragonite using sem geologia croatica 203 they concluded meigen’s solution was not effective for recrystallized or coarse-grained aragonites. feigl’s method was useful for such samples and investigations. in this paper, in the description of the possible use of morphological observations, geochemical properties and feigl’s staining method are presented as useful tools for studying calcite and aragonite, separately or in mixtures, with scanning electron microscopy. failure of the experiment described by suzuki et al. (1993) is the result of inconsistency in the solutions temperature, chemical composition and staining duration. careful control of these parameters improves feigl’s staining method as a useful tool for identifi cation of biogenetic calcite and aragonite using sem. 2. materials and methods two different groups of samples containing calcite and aragonite were studied. the fi rst group consists of bryozoans pentapora sp. skeletons from the adriatic sea, collected on jabuka shoal from 40 to 50 m depth. a second group consists of white, sometimes macroscopically green stained sediment found around the hot well in varaždinske toplice spa. this sediment precipitated from hot water, at least partially under the infl uence of some microorganisms. mineral phase determinations of the bulk samples were done using a philips x’pert powder diffractometer, with cukα radiation fi ltered with a graphite monochromator running at 40 kv and 40 ma. an x-ray diffraction data set was collected from 4 to 63º2θ. preparation of samples for sem observations was not completely identical. samples of bryozoans were fi rst clean ed from their organic parts, and then fractured, fi nely ground, polished and mounted on the sem stubs. they were not additionally etched prior to staining. samples of hot well sediments were simply mounted on the sem stubs. both groups of sediments were then sputtered with carbon. morphological observations on the samples were carried out using a tescan ts 5136 scanning electron microscope (sem). for examination of the samples, the sem was operating in back scattered (bse) mode at an accelerating voltage of 20 kv and current of 10 ma. the same sem microscope equip ped with the oxford energy dispersive spectrometer (eds), coupled with inca 250 system, was used for elemental distribution analysis in the samples. eds qualitative analysis and elemental mapping was performed on the carbon coated samples at an accelerating voltage of 20 kv. morphological observations with sem and elemental analysis with eds on hot well sediment samples from varaž dinske toplice provided enough data to conclude the presence and relationship between calcite and aragonite. so, only the bryozoan samples were stained using feigl’s staining method. the feigl’s staining method is based on the reduction of silver and manganese cations by hydroxyl anions released during aragonite dissolution, because aragonite is less stable than calcite; the solubility product of aragonite (6.0 · 10–9), represented by product of the concentration of ions (mol/ dm3) is larger than solubility product of calcite (4.5 · 10–9) (krauskopf, 1994). the staining process could be described by the following equation (feigl, 1937): carbonate dissolution: caco3 + 2h2o ↔ ca2+ + h2co3 + 2oh– reaction of the cations with hydroxyl anions: mn2+ + 2ag+ + 4oh– ↔ mno2 + 2ag° + 2h2o the result is precipitation of manganese dioxide and metallic silver on the carbonate surface, where the maximal concentration of hydroxyl groups lies. the precipitate is black in colour observed by naked eye or using a binocular microscope, (because both colloidal silver and manganese oxide are black), contrasting generally with white calcite and aragonite. the solution is prepared according to the original recipe (feigl & leitmeier, 1933). 1 g ag2so4 is added to a solution of 11.8 g mnso4 · 7h2o and 100 ml distilled water. the mixture is boiled, cooled and fi ltered. it is very important to neutralize the mixture with dilute sodium hydroxide until a black precipitate starts to form. after neutralization, the solution must be re-fi ltered and kept in a dark bottle. samples of bryozans pentapora sp. were not stained over a set period of time, but until formation of the fi rst light colouration. aragonite surface colour changed from white to grayish over one to three minutes; more prolonged staining resulted in a completely black aragonite surface. it is very important to control the complete staining process under the binocular light microscope. during staining, the solution was at room temperature. 3. results x-ray powder diffraction patterns proved that both the carbonate shell of the bryozoan pentapora sp. (fig. 2a) and hot well sediment from varaždinske toplice (fig. 2b) are composed of a mixture of aragonite and calcite. using the sem equipped with back scattered electron detector it was possible to recognize both calcite and aragonite crystals (fig. 3a) on the samples from varaždinske toplice. recognition was based on their crystal habits. using of eds allow confi rmation of calcite crystal(s) or its agglomerations (fig. 3b) and aragonite (fig. 3c), because calcite contains a small but important and recognizable amount of mg, and aragonite contains a small but important and recognizable amount of sr. small amount of s precipitates together with calcite and aragonite in the natural environment of the hot wells. morphological observations on the bryozoan samples were not so successful, because the crystal habit of skeletonbearing carbonate minerals could not be observed, due to close packing of the crystals. eds qualitative analysis and elemental mapping show that mg is present in the inner part of a shell. bryozoan pentapora sp. samples were then stained using feigl’s staining method. cross sections of bryozoan pentapora sp. samples show ed differential staining indicating a bimineral skeletal composition (fig. 4). geologia croatica 62/3geologia croatica 204 fi gu re 2: (a) xrd pattern of the sample pentapora sp.; (b) xrd pattern of the sample from varaždinske toplice; both showing a mixture of calcite and aragonite. cal – calcite, arg – aragonite, s – traces of coprecipitated sulfur, al – aluminum from the sample holder. fi gu re 3: (a) typical mixture of calcite and aragonite developed aro und the hot water well, in varaž dinske toplice under extreme conditions for living microbial orga nisms. cal – rhombohedral crystals of calcite, arg – sharp, needle like, crystals of aragonite. (b) eds spectrum of calcite with minor content of mg. (c) eds spectrum of aragonite with increased content of sr. small, but measurable amount of sulfur also precipitate on the surface of these carbonates. a b a b c žigovečki et al.: identifi cation of biogenetic calcite and aragonite using sem geologia croatica 205 stained aragonite areas are covered with nanogranular manganese and silver precipitates, which do not completely cover the bryozoan microstructure, allowing very detailed examination. the calcite part of the shell was almost without any cover. the black stain is easily recognizable macroscopically and under binocular light microscope, but is also easily recognizable using back scattered electron detector (bse), because bright surfaces, rich in silver and manganese, on images indicate aragonite. using light microscope allow to recognize presence of aragonite and/or calcite, but using of electron microscope it is possible to recognize the fi ne textures, for example the structure of outer bryozoan shell on the sem bse image. mapping of such stained areas shows that there is colloidal silver and manganese oxide deposited homogeneously on aragonite (fig. 4). 4. discussion many shells or skeletons have a bimineral composition. the ratio of calcite and aragonite could be determined by x-ray investigation (anderle et al., 1998). such organisms usually have an aragonite inner and calcite outer layer of the shells. however, this could also be the opposite way around. it is not possible to recognize this arrangement using x-ray diffraction, except if it is combined by careful and sometime impossible separation. nevertheless, it is possible to stain the sample by feigl’s solution. using feigl’s staining method in combination with sem bse observation provides the opportunity to recognize not just aragonite distribution inside the shell wall, but also any fi ne textures. the rates of dissolution of calcite and aragonite in the feigl’s solution control the intensity of manganese dioxide and metal silver precipitation and the size of deposited particles on the crystal surfaces. aragonite dissolves more rapidly in the staining solution and will be stained by silver and manganese oxide, while calcite reacts slower and remains unstained. the speed of carbonate dissolution and staining is altered if the staining solution concentration or temperature is chang ed. however, the speed of dissolution also depends on carbonate crystal size. dissolution speed decreases with increasing size of the mineral grains. the rate of dissolution also varies with the crystal orientation, because of anisotropy. improper use of feigl’s method (e.g. too fast or too slow dissolution) produces coarse grains of metal (ag and mno2) fi gu re 4: (a) sem bse image of the stained cross section of bryozoan pentapora sp. with aragonite in the outer part and calcite inside the carbonate shell. such images highlight the fi ne texture (smaller than a few tens of a micrometre), of the calcite and aragonite mixture of the outer shell. (b) map of ag. (c) map of mn. there is no signifi cant diff erence between silver and manganese oxide deposition on the smooth aragonite surface. a b c fi gu re 5: sem bse image of the manganese-oxide and metal silver precipitate on the aragonite surface of pentapora sp. the precipitate is very coarse (up to 100 μm long) because of rapid aragonite dissolution in the very acidic feigl’s solution. such preparation is inadequate for the microstructural observation of aragonite microstructures. white fragments are silver particles and gray particles are manganese oxide. geologia croatica 62/3geologia croatica 206 up to a few μm in size. the grains of silver and manganese oxide are too big for observing fi ne texture and cover both minerals – aragonite as well as calcite. this will happen when the solution is too acid and the procedure is too rapid. such conditions caused failure of the method in the case of suzuki et al. (1993). if the ph is too low, dissolution of both calcite and aragonite produce an inconsistent and inadequate stain, as can be seen in fig. 5. meigen’s solution containing hcl acts more aggressively on aragonite dissolution than feigl’s stain. this means that feigl’s staining method allows preservation of more of the delicate mineral features of the bryozoan mineral textures (up to 10 μm). if the staining procedure is carried out carefully, with binocular light microscope control, it is possible to obtain a black manganese oxide and silver precipitate of nanometer size. if feigl’s solution is not neutralized properly, biogenetic carbonates will be corroded on the surface and this process will be easily visible using sem bse. so, suzuki et al., (1993) dismissed feigl’s staining method without any reason and favoured the less successful meigen method. 5. conclusion identifi cation of aragonite and calcite is very simple by x-ray diffraction methods. but, it is not possible to describe the textural distribution of these carbonates using such methods. the fi rst and most logical aragonite-calcite differentiation by sem bse is on the basis of crystal morphology. biogenetic carbonates, i.e. those mostly precipitated under microbial control, could sometimes be recognized (fig. 3a). however, in most of the biomineralized skeletal structures, the typical crystal morphology is not developed. discrimination of two carbonate phases could be based on the large and small cation (usually strontium and magnesium) content of aragonite and calcite respectively, determined by eds if these elements are present (figs. 3b, 3c). if none of the above-mentioned methods could be applied, staining methods alone will be useful. staining with feigl’s solution can be successfully used for observations in mixtures in biogenetic carbonates using sem bse examination. feigl’s solution cannot be used as a standard procedure with fi xed staining time or prescribed solution temperature. because of this, binocular light microscope control is necessary. the difference in crystal structure of aragonite and calcite produces varying dissolution rates and without carefully monitored staining procedure, they will show inconsistent results or a coarse precipitate. acknowledgement this work was supported by the ministry of science, education and sports of the republic of croatia, under grants no. 119-0000000-1158, 119-1191152-1169 and 098-0982934-2742. references anderle, h., steffan, i., wild, e., hille, p., bermanec, v. & sövergjarto, f. (1998): detection and dosimetry of irradiated biominerals with thermoluminiscence, radioluminiscence and electron spin resonance measurements: comparison of methods.– radiat. meas., 29/5, 531–551. doi: 10.1016/s1350-4487(98)00038-9 anthony, j.w., bideaux, r.a., bladh, k.w. & nichols, m. c. (2003): handbook of mineralogy – vol. 5 – borates, carbonates, sulfates.– mineral data publishing, tucson, arizona, 813 p. ayan, t. (1965): chemical staining methods used in the identifi cation of carbonate minerals.– b. miner. res. expl., 65, 133–147. bragg, w.l. (1914): the analysis of crystals by the x-ray spectrometer.– proc. r. soc. lon. ser.-a, 89, 468–489. doi:10.1098/rspa. 1914.0015 bragg, w.l. (1937): atomic structure of minerals.– cornell university press, london, 292 p. dickson, j.a.d. (1966): carbonate identifi cation and genesis as revealed by staining.– j. sediment. petrol., 36/2, 491–505. effenberger, h., mereiter, k. & zemann, j. (1981): crystal structure refi nements of magnesite, calcite, rhodochrosite, siderite, smithsonite and dolomite, with discussion of some aspects of the stereochemistry of calcite-type carbonates.– z. kristallogr., 156, 233–243. feigl, f. (1937): quantitative analysis by spot test.– nordemann publishing company, new york, 400 p. feigl, f. & leitmeier, h. (1933): “spot” test to distinguish calcite and aragonite.– microchem., 13, 136–138. friedman, g.m. (1959): identifi cation of carbonate minerals by staining methods.– j. sediment. res., 29/1, 87–97. doi: 10.1306/ 74d70894-2b21-11d7-8648000102c1865d goldschmidt, v. (1913a): atlas der kristallformen – band i.– winter, heidelberg, 244 p. goldschmidt, v. (1913b): atlas der kristallformen – band ii.– winter, heidelberg, 251 p. kato, k., wada, h. & fujioka, k. (2003): the application of chemical staining to separate calcite and aragonite minerals for microscale isotopic analyses.– geochem. j., 37, 291–297. doi: 14039. 35400011830925.0100 krauskopf, b.k. (1994): introduction to geochemistry.– mcgrawhill, inc. new york, 640 p. palache, c., berman, h. & frondel, c. (1951): the system of mineralogy of james dwight dana and edward salisbury dana, 7th edition – vol. 2. – halides, nitrates, borates, carbonates, sulfates, phos phates, arsenates, tungstates, molibdates, etc.– john wiley and sons, new york, 1124 p. sass, r.l., vidale, r. & donohue, j. (1957): interatomic distances and thermal anisotropy in sodium nitrate and calcite.– acta crystallogr., 10, 567–570. doi:10.1107/s0365110x57002029 speer, j.a. (1983): crystal chemistry and phase relations of orthorhombic carbonates.– in: reeder, r.j. (ed.): carbonates: mineralogy and chemistry. rev. mineral. geochem., mineral. soc. america, washington, 145–190. schneidermann, n. & sandberg, p.a. (1971): calcite-aragonite differentiation by selective staining and scanning electron microscopy.– trans. gulf coast assoc. geol. soc., 21, 349–351. doi: 10.1306/a1adf466-0dfe-11d7-8641000102c1865d suzuki, s., tago, y. & hikida, y. (1993): using meigen’s staining for aragonite-calcite identifi cation in fossil molluscan shells under the scanning electron microscope.– j. geol. soc. japan, 99, 1–7. šebečić, b. & slovenec, d. (1990): aragonite in kerogenous lower cretaceous carbonate rocks of mt. dinara.– geol. vjesnik, 43, 91–95. manuscript received june 02, 2009 revised manuscript accepted september 18, 2009 available online october 30, 2009 geol. c roat. 50/1 89· 103 19 figs. 2 tabs. zagreb 1997 pliocene source rocks, miocene reservoir rocks and origin of the gas accumulation of the irma field (northern adriatic, croatia) based on wireline-logging ivica vulama key words: pliocene source rocks, miocene reservoir rocks, messini an unconformity, wirc line logging, geochemical analysis, discriminant function, over­ pressure zone, biogcnc gas, middle adria tic ridge, croatia. abstract the pliocene source rocks of the middle adriatic ridge appeared to be thermally immature. according to ihe geophysical and the geo­ chemical anal yses, but they may have produced biogcnc gas . wirelinc logging co nfirmed theil' broad ex tent. correlation between geophysi­ ca l :h1d geochcmicul data indicated their di stinguishing parameters: gr = 55 125 ap i, u2.18= 5 25 ppm, rt = 1.5 4 ohmm, 6,= 75170 ps/ft (x 0.306 il s/ill), po,(= 1.6 1.9 g/cml, ¢in = 33 39%, sp =-44 (-) -56 my, corg. = 0.43 3.23%, v",(%) = 0.47·0.66, k{fh = illite. these organic mm ler have been classified as a kerogene type iii-ii. characteristic geophysical parameters of the miocene reservoir rocks arc: $::: 22%, r ... :::; 0.18, iii :::; 1.8, fr :::; 15.3, ro::: 2.75 ohmm, k avg. ::: 2 1.4 x 10 3 pm!. favorable lithologictectonic conditions (overpres­ sure zones, normal faulting) led to gas accumulation in miocene cal ­ care nit es ami sandsto nes. the pliocene source rocks discordantly overli e mioce ne rese rvo ir rocks, separated by the messi nian uncon ­ formit y. statistical analyses show that, alt hough the pliocene shales arc thermall y illllllalure, they fit into the model of source roc k recog­ nition. 1. introduction the irma oil fie ld is located in the soulh -west part of ihe middle adriat ic ri dge alon g the border line between croatia and italy (r ig. 1). the slructural-con­ tour map fo r the mess in ian reservoir (se ismi c marker "a") shows posi li on where irma-1 well was dril led, and more to the northwest where irma-2 well was drilled. the whole area is represented by an ant ic linal closure spread ing sou thward over the inte rnational boundary li ne, onto the barba ra field in ita ly. to the north , the structure is closed by a normal rault wi th 26 m throw (figs. 1 and 2). pliocene sed iment s discordantly ove rlie the miocene deposits beneath the 1v1css inian unconformity. in ihe lower part o f the transgressive seq uence, these pliocene sed im ent s have source rocks characteristics ina-na ftaplin, subiceva 29, hrioooo z lgreb. croatia. kljucne rijeci : pliocenske maticne stijene, mioeenske kolek lorske sti jene, mesinijanska diskordaneija, gco fi zicka mjerenja, geokemij ske analize, diskrim i­ nan tna funkcija, nadpr iti snute zone, bioge ni plin, srednjojadranski prag, i-irvatska. saietak pliocenske malicnc stijene srednjojadranskog praga pokaza le su se prcma geokc mijskim anal izama terrnalno nezreti m, al i imaju mogllcnosl pro izvodnje biogenog plina. primjenom geofizic ki h mjcrenja ii busot inama li tvrdena je njihova iiira rasprostranjenost, te sli korelacijom geofiz ickih i geo kcmijsk ih mjerenja utvrdeni s ljedcci paramelri 7-<1 njihovo prepoznava njc: gr = 55 125 ap i, u2.ls= 5 25 ppm, rt = 1.5 4 ohmm, d.,::: 75 · 170 )1s/ft (x 0.306 f-ls/m), poi = 1.6 1.9 g/em), ¢in = 33 39%, sp = -44 (-) -56 my. corg. = 0.43 3.23%, v 01(%)::: 0.47 0.66, krrh ::: illite. klasificirane sll kao tip iii i ii kerogena. karak teri sl icni geofi7-ic ki pa ra melri m ioeensk ih rezer­ voarskih slijcna plinskog polja inna dobiveni iz gco fi zickih mjerenja u busol in<lma su: ¢i = 22%, rw = 0. 18. iii = 1.8, fr = 15.3, ro = 2.75 ohmm, k avg. = 21.4 x 10 3 pm2 • povoljni litoloski i tcktonski uvjcti (nadpri ti snlltc zone. nonnalno prot li sllljerno rasjedanje) li zrokovali su nakupljanj e plina u mioce nskim ka lk areni tim a i pj e.~cenjac i rna na koje nalijczli pl ioccnske mati cne stijene cij u grani cll cini lllcsinijan ­ sk<l d iskordaneija . statisticka j c a naliza pokaza la da se plioeenski sejlovi, iako su tennalno nezrcli, mogu opisanim mctodama prcpoz­ [tati kao maticne sl ijene. recogni zed by wire lin e log interpretation, and co n­ firmed by geochemica l ana lyses . the seismic marker "an also represents an excellent wireli ne logging mark­ e r in the base of the source rocks recognized on the wells inna· l , 2, 2a, 3, 4, suz· l, incsi, lngal , lini, j7, j·22/l and j 23/1 (figs. 2 and 3). the source rocks probably also extend soulhward across the border with ll a ly (barbara fi e ld) bu i ihc iialian well dala arc noi avai lab le fo r study. previous work in these area emphasize the ex istence of source rocks in the region of midd le adriatic ridge (vulama, 1991, 1994). t he geological sclling of ihi s a rca was documcntcd by kadija c t al. (1991 ), kadi­ ja (1992), t ari kovacic ( 1995) and miletic & lugovic ( 1996). geochcmical dala wcrc provided by l na-nartaplin laboralory. the input data base comprised resistivity, acoust ic, densit y, apparent neutron poros ity, spontaneous poten­ li a l, rnicrolog and spectralog (k, th and u) loggi ng responses with a secondary geochemi ca l data base: 90 fi g. 1 locat ion map or the middle adriatic ridge source rocks in the sludy arca. cargo content , tmax. from pyrolysis, hydrogen index, vit ri nite re fl ec tance (ra), and genetic potential s i and s2' the possibility of the recognition and qualification o f immature pliocene source rocks, which possibly pro­ duce biogen ic gas is discussed toge ther with the origi n o r gas accumulation in gas field imm based on wirel ine loggi ng. the applied methods include classical logging data computed and interpreted through various res isti vi­ ty, acoust ic, density, neutron e lc . combinations of c rossp lols and s tatis tica l anal ys is (discriminant fun c­ tion) corre lated wi th geochemical analyses. j-5 + geologia croalica 5011 2, stra tigraphy the lowermos t cretaceolls, palaeocene , eocene, oligocene, miocene, pliocene and quate rnary sedi­ ments were drilled across the explorati on area. onl y those miocene, plioce ne and quaternary sediments which are related to the described source and reservoir rocks arc discussed brieo y. the miocene sed im ents are represented by light gray limestones and g ray 10 li ght gray fossilife rou s marls. the quantity of clay in th e limestones varies from 10-80 %, while sandy limes tones (cal ca renites) often occur, which represent good collectors, the aver­ age depth of the top of the miocene sediments is approximately 1500 m (kadija , 1992), pliocene sediment s arc mostly represented by less fossiliferous gray 10 dark gray organicri ch shales, with inte rbedded sand and silt (mileti c & lugovic, 1996), the average depth of the top o r the s ha les is approximately 1420 m (kadija , 1992). quaternary sediments are represented by marls, c lays and poorly to non conso lidated sands and s ilt s, and in the shallower part s by coa l int e rbeds. in the deeper part (below approximately 1200 m) marls are more frequent, where the overpressure zo ne begins. tn the deepest parts above the pliocene sedim ents , lower concentrat ions of organic mailer were observed. 3, tectonics t he w ithdrawal of the african plate beneath the euro-asian plate form ed the adriatic depression situa t­ ed between the upl ifted oute r dinaridcs anclthe apen­ nines (prelogovic & kranjec, 1983), eocene carbonate platform (mesozoic to miocene) .\ffi' .\'5~ legend .\'560 e::d source rock distribution ~ tor of" a" reservoir o tecfonic·erosion unconformity ~ normal fault a-a' profile fig. 2 si ructural contour map of ihe top of the "a" reservoir (after kadlja ct ai. , t991) of the trma gas field with di stribution of the source rocks over­ lying the lop o f ihe reservoir (pro fil e s­ b'). vlll,llll,l: pliocene source rocb. miocene reservoir rocks and origin or the gas accumulation ... 91 ."trr.ill[ ~n· ir~ma· l irtv\a·4 j 23/1 q'ali' 6000 1000 '500 1100 ;000 >500 1200 ;00 ~ 1300 3~ 2 :;:; 1400 ",00 i= 1500 3000 <5"" 1600 6000 1700 1800 fig. 3 seismic section profile a-a' with position orthe source rocks and "a" gas reservoir. tecton ic movements caused normal faulting (figs. 2 and 3) and the uplifting of the "middle adriatic ridge" area. the eocene fault zone remained active during the miocene when fault related traps were formed. erosion of the uplifted sediments infilled the adriatic depres­ sion. the depositional surface of the pliocene sedi­ ments was dominated by multi phase tectonic activity, as well as quaternary sediment deposition. these tec­ tonic movements caused [aster subsidence of the african plate which exceeded deposition rate, and resulted in deposition of transgressive sed iments in a north-east direction. this explains the increased sedi­ ment thickness of the south-\vest and reduced sequence 10 the north-east. 4. geophysical wireline-log respon­ ses characteristic for source rocks in llase of the pliocene shales all the ava il able logging surveys: natural radioac­ tivity, sonic transit time, bulk density, apparent neutron porosity, formation resistivity, spectralog, crossplots and statis tic analysis were applicd to determine the recognition and classification of the source rocks. 4.1. natural gamma-ray logging the increased natural radioactivity in the clastic and carbonate sediments is the first indication of a possible source rock, if the sediments arc or marine origin. fresh water source rocks do not show high natural radioactiv­ ity because fresh water docs not contai n uranium ions. in the pliocene basal shale natural radioactivity as high as 130150 api un its has been observed, while the basal and uppermost sediments can be characterized by 40-i!o api units (figs. 4. 5 and 16). 4.2. sonic transit time logging sonic transit time logging (lj.), as well as bulk den­ sity logging, indicate differential compact ion between sediments poor in organic matter and the source rocks. sonic transit time indicates the organic rich layer within the impermeable sediments (figs. 4 and 5). the sonic transit time wireline logging is more useful than bulk density logging in the cases where the hole is rugose or if heavy minerals (e.g. pyrite) occur. as the sonic tran­ sit time is a function of several factors (water organic matter relation, mineral content, carbonate and clay content and pressure), it is always useful to apply com­ binations of the various types of logs. the various erossplo t combination of sonic transit time and resistiv­ ity proved very effective. the most often used cross­ plots include the following com binations: sonic transit time, formation resistivity, bulk density, natural radioactivity, apparent neutron porosity or cores corre­ lation's (calibration), as presented on figs. 4 and 5. sonic logging can also be applied to calculate the total sonic transit time (ms) and the interval velocities (m/s), which can distinguish the source rocks (fig. 6) . the interval velocity curve (ltvi ) shows the clear decline of the sonic transit time in the source rock zones. 4.3. bulk density logging bulk density (pb) is a function of matrix density (pilla) and tluid density (pr)' the greater the tluid content 92 geologia croal ica 50/1 irma-i pliocene source rocks middle adriatic ridge ~ f ~ i ~ ? ~ ~ , ~ " ~ ~ ~ 1< i ~ ,~ < ~ j) 1=( j f ? ~ ? ~ ,~ ~. ~ < ~ 1 ~ ~ , <;;; 1< t(, §f~ <i ), ~ ~f" ~ l<i "i---p i !? ,1 ~ < !:::: i ,1m r r r-~ !:;~ !c-i i£:; t ~l' ~ po f) ~ 1 i < o f the formation, the g reater the rock porosity. the equation 1'01' calculating rock porosity ($) is as follows: <i>=(p",;,-pb )!(p",,,-p,). in marl s (sha les) with almost identical degrees or compac tion, all the physical parameters, even the waler saturati on (s,...) arc equal. if the source rock density (p,lr) is lower than the shale-marl density (p.\h)' then organic matte r (pom) is present , and this implies that these marls (shal es) are impermeab le and indicates that the rock density decline is not the result of the hydrocarbon (fl u­ id) presence in the rock. within the above mentioned assumptions it is possi­ ble to calcul ate the vol ume percentage of the organic matter v 01(% ): vo(%) = (p ~h psr)/(psh pom) the density of organic matter (pam) is almost equal to the water density (pwl = 19/cm'. the average vo/%) value for middle adria ti c ridge source rocks is 0.47 -0.66 %. fi gures 3, 4 and 8 show the decline in bulk density in the source rock zone compared to the overlying and underlying layers . bulk density loggi ng in the layer 1< \ ~ ~ i~ ~ ~ ~ i} ~ "~ p. ~ s fig. 4 composit e log responses char­ acteri st ic ror pliocene sou rce rocks. irmai. above the source roek interva l (irmai we ll ; pliocene deposits silt-shale) sugges ted 2. is g/cm' as the aver­ age bulk density while in the source interval th is value was 1.6 g/cm3 . the average vertical resolution of the wire logging tools foc (sch lumberger) and col (dresser atl as) for rock dens ity survey is around 60 cm. in recognizing source roeks by bulk density logging, specia l aucntion should be paid to the highe r concentra­ tion of heavy mineral s, especially pyrit e indicating rcduci ng conditions (as well as the presence or organic matter). radioact ive thorium th232 is vcry often bonded to pyri te, as in the case of the irma gas fi e ld (figs. 4 and 5). hole rugosity is also important due to the pres­ e nce of fluid in the increased hole diam ete r. this applies similarly to strata containing fluid in pore/frac­ ture space. 4.4. apparent neutron porosity logging apparent neutron porosity loggi ng (tpn) is primarily performed in the evaluation of the porosity and litholo­ gy. the meas urement is pr im ari ly the response of vul:mw: pliocene source rocks miocene reservoir rocks and origin of the g"is accumuhtion 93 irma2 pliocene source rocks middle adriatic ridge i~ ~ ;. f2;. 1 ~ l ;:, jj \ ~ k'> '?<p ( ') < ~ po ( ) .; ~ p f~ t>i.e i~ ~ ~ ~ f.'p. ~ i~~ '~ t " ~ ~f ~t :> :> ~ > ~ 50 '" ~p f---,s ,> h f= ~ cr? f:: b, 1 [;> 1-:;:; ~ > = \ "" i i':' -= ( d .-~ <1 j m i}' { ~p ,;s, i~ ~ c g , ? i , 11f1 < !" gr ,e , rmlll , , ac cn , . ,, __ ~p __ 2 ' . , ... r~lm .... " , p. t1 ll i q 10' ,1 .0 ••• ~ i.l.'~-." •• !<:' ,! £ __ r~~~_-~) _! <:.< . 1 __ ~i:r: __ j~ hydrogen atoms present in the rock (they are mostly bonded (0 fluids or organic matter hydrocarbons). whcn the hydrogen atom concentration is high, the high -energy neutrons slow down and arc captured in the nuclei at a short distance from the logging tool. accordingly, any increase in the concentration of hydrogen atoms will cause an apparent increase in neu­ tron porosity, registered by logging tool counting. it can be interpreted as the presence of fluids, free hydrocar­ bons and/or organ ic matter in the pore space. the shales and silty shales arc impermeable rocks, so it is expected that the apparent porosity increase is caused by the higher concentration of hydrogen atoms of organic matter (figs. 4, 5 and 8). 4.5. formatfon resfstfvity logging any formation resistivity logging can be used to recognize source rocks. for impermcable rocks, both :::; r f> ..:; :;, is> \ < i> 5" ) ~ ~ i ? k { ~ ~ 1<; i§. ~ i ~ ~ f"' den k ~ , u ~~ fig. 5 composile log responses characteristic for pliocene source rocks,lrma-2. shallow and deep surveys should give same or similar conductivity values (formation rcsistivity; figs. 4 and 5). it is necessary to lise mieroresistivity measurements in the cases of thin intercalat ions of organic matter in shales, marls etc. these appl iances are characterized by considerably better vertical resolution. an example is presented on pigs. 4 and 5 (irma-l and 2), in the source rock zone the deep induction log (rt, rild) docs not show increased resisti vi ty , although, according to the other surveys and geochemical analysis the high toe of that interval has been recognized (vulama, 1991, 1994). however, the microlatherolog measurement (rmll) indicated higher resistivity in the same inter­ val. source rocks are often laminated and therefore elec­ trically anisotropic. this anisotropy increases the resis­ tivity of the interbedded organic-rich layers, especially when the source rock is mature. resistivity can indicate source rock maturity (vulama, 1991, 1993, 1994). 94 geologia croalica 50/1 irma-2 middle adriatic ridge pliocene source rocks b:: i ~ f' ~ '" ~ i -'~ ~\" • i" f: 'jj = ~ i ~-~ ~ -,., =-~ ~ > : -" =it"-i-i~ ~ ~ ti1 1::,::: . § :::c 'jj == " ff-~ ~ -, ~ "'" i--< !f !i .~ ~ ~ ~-~f 1? ~ c/o , ;t ~ c/o ~g -=r § ---t i:=" (l :: :r ~ 1[jj ~~ ._f'~ t a s ~ ro~ £ if. ~ l ~~ ~ ,"'-'i:'_ "t b-~ ~~ ;;l '" -ii den_lli i. 1 gr . fig. 6 composite log responses of the pliocene source rocks on sonic (ac), bulk density (den) , gam­ ma ray (gr) and sonic in terval transit time (ltv i). note the cbar­ ac teristic sonic and density log response (increase of sonic transit time, decrease of bulk density) of the overpressure zone beginning approximately at 1260 m depth . .... example of an isotropy (laminae) and low maturity (low resistivity val ues) can be seen on fi gs. 4 and 5 (rmll). the irregular hole diameter (rugosity) can influence the formation resistivity. this is morc obvious in case of shallow investigation tools. further more, resistivity values can be influenced by rock anisotropy (different vertical and horizontal res istivity), tcmpcralure and wire logging tool characteristics (investigation depth, invasion diameter, vertical resol ution and the geometri­ cal factor). 4.6. natural gamma ray spectrometry (spectra log) spectralog proved to be the most reliable method in recognizing the presence of organic matter. numerous exploralionisls (schmoker, 1981; meyer, 1984, etc.) recogn ized that the hi ghcr radioactivity of the source rock zone is related to the uranium (un x) content of the sediments (figs. 4 and 5). it is assumed tha t plankton and various organisms absorb the uranium salts (ions) from the sea water togethcr with other rare elements and in this way uranium is concentrated in source rocks. it is also necessary to pay attention to the concentra­ tion of heavy minerals, especially pyritc, as its origin is connected to reducing conditions as well as organic matter. radioactive thorium th 232 is very often bonded to pyrite as is the case in the wells of the irma gas field (figs. 4 and 5). recogni tion of high uranium radioac tivity in marine sed iments is almost certai nly indicative of the organic richness of those rocks, as it was confirmed by numervulama: pliocene sollrce hocks, miocene i{eservoir rocks <lnd origin of the gas acclljlllllrttion ... 95 ~ ~ ~ ::: 20 ;§ i /; '8 on 0. .~ -s 16 " " i 0 ·c fl ;l '0 12 0 u ~ " 0 u t' ~ '" 8 ~ '<1 0 f: ~4 ~ • 0 0 2 3 4 fig. 7 thorium vs. potassium crossplot of the pliocene sou rce rocks. k, potassium concentration (%) ous studies for the croatian exploration area (vula­ ma, 1991, 1993, 1994). there arc published case stud­ ies where uranium is concentrated in fracture systems through which connate water flows (uranium is not transported by migration processes because it remains bonded to the heaviest hydrocarbons in the organic maller). however, the existence of such fractures in our wells has not been confirmed. 4.7. source rock identification by cross plots numerous autilors (meyer & nederlof, 1984; fertl & chilingarian, 1980, 1990; schmok­ er & hester, 1990, etc.) used various combinations of crossplots to identify source rocks. the most com­ mon combinations were: bulk density and true (forma­ tion) resistivity or sonic transit time and true resistiv ity. i r m a 2 (middle adrlatlc ridge) " •• " ~~~ , :, ' " "" , o ¢ ¢¢ cc~o ~" " "¢,, ~ ~ i , " , , , ~~ , ~"" "* • ~:t¢6's , w¢ u ~ci' dft -¢-.;.<:> ~\ " "" ito 0 9 0 ~l" tljg ~ "" " " .;.,t 0°-¢-'~j: ». , ¢ij~g.. " •. '.3 'ii' i\ ", ~~'>,,~j~¢~ , 1\11 'g, • -¢-.;.-¢-.;. o~ , ' , $3 ¢ .;. , , ~ , . • . " , , ' . tf.;.~ , ' • , ~ , , ~/.;. • .;.*-\ . '" . . " ';'.;.--:4 -¢• ~ ffi '.1 " '" ;:l '" 152s. 1s44m {o) shale 1s44-1smm (-¢-) source rock ls64-1s81m (¢) calcarenite is81·1s8&m( o) sandstone 1.9 10 15 20 " 30 35 compensated neutron porosity (%) these combinat ions of two-component diagrams proved to be useful for qualitative rock evaluation. four types of measurement arc included in the four component m/n/(z) and a/k/(z) diagrams: bulk dens i­ ty (pb)' apparent neutron porosity ($n)' sonic transi t time (~) and as the fourth component a measurement representing the third dimension z (natural radioacti­ vi ty or or certain part of the spectrum k, u or th , or spontaneous potential sp, as a rock permeability indicator). m,n and a,k arc practically related to rock porosi­ ty. organic matter is less dense and compact than the rock matrix and gives the reflect ion of apparent porosi­ ty. m, n, a and k arc reached by survey combination calculation as follows: where ~t = sonic transit time; ~! r = sonic transit lime in 3 zm~ o zmin 0 " fig. r hulk density vs. compensated neutron porosity vs. z (u ranium) crossplol of the pliocene so urce rocks. 96 2.' ,-. ~ '" ";..r 1.9 -3, d 0 ....:l 1.4 0 180 160 140 ,-. ~ '" :::l 120 ~ ~ 100 80 middle adriatic ridge source rocks • {> {> i 000 o~ 0 (d) non source rocks o d=-17 .866+8338'log(ac)+ 1.213 ']og(rt) 2.0 log (rt, ohmm; 24°c) o o o 00 o o a a d=148.44-s.44*mll+o.119*ac 1 2 3 mll(ohmm) 4 5 '.0 zmax 150 zmin o geologia croatica 50/1 fi g. 9 soni c transit time vs. resisti vit y cross1'101 ploued all logarithmi c scal e. the oblique line is the position of d=o (dis­ criminant analysis), points above thi s line (d=positivc: star) = source rocks; points below this line (d=ncgative: rectangle) = non source rock. the analyses arc from an area of the middle adriatic ridge, sava and drava depress ion (aftcr vula ma , 1994). fig. 10 sonic transi t time vs. resist ivity c ross­ plol plolted on linear scale. t he oblique line is the position o r d=o (disc ri mi nant anal ys is). point s above thi s line (d=posi­ tive: star) = so urce rocks; point s below ihi s line (d:negat ive: rectan gle) = non source rock. the analyses arc from un area or the middle adriatic ridge. water ( for fresh water it is 189 j-ls/ft , whe reas for the sail water is 185 ).is/ft · 0.306 ).is/m); pb = bulk density (g/cm3 ); pr = fluid density (for fresh watcr it is 1.0 g/cm3, whereas for salt waler it is 1.1 g/cm3 ). wate r poros ity which is 1, or 100%, so the equation should read: n = ( i 'i>n) / (pb prj a = (pb pr) / (l 'i>n ) where 4>n:::: apparent neutron porosity (%); 4>nr = neutron k = 0.01 (6,,6,) / (i 'i>n) 0.6 ,----------,---------, non source rocks (0 ) .0 ". do {> {> {> tf: ~ 0 ~ 0lj -.............. source rocks (v ) .• 0.25h~et__tto_~~=-----=-'-_i¥l'-----------=-==-==>.'-'--1 .0 middle adriatic ridge 4----source rocks i 0=-5.326+ 19.366*log,iden)-1.461 *loglo(rn ol-__ ~~~ ____ ~~ ____________ ~ o 2.0 4.0 fig. ii bulk density vs. resistivi ty crossp[ot plo lt ed on the logarithm ic scal e. t he oblique line is the positi on of 0 =0 (dis­ c riminant analysis). points below thi s line (d=positive: sial') = so urce rocks; point s above ihis line (d=negalive: rec­ tangle) = non so urce rock. the analyses are from a n area or the middle adriatic ridge. sava and drava de press ion (after vulama,1994). log (rt, ohmm; 24°c) vulama: pliocene source rocks, ,vlioeene reservoir rocks and origin of the gas accumulation .. m~ s ib .0 a. ~ z ~ q 2.4 2.2 2.0 1.8 1.6 1.4 1 2 d=2.24-6.309*n+3,706*m d=1.72+0,098*mll-io.15*den 3 mll(ohmm) 4 5 zmax 150 zmin o o~ ______________ ~ ________________ ~ 0.5 1.0 1.5 n 2.0 1.8 1.6 1.4 a 1.2 1.0 0.8 0.6 middle adriatic ridge source rocks d=-o,27s+ 1.22*k-o.82* a non source rocks ( ,, ) zmax 35 zmin o 0.4 l-_ ____ ___ _ ---.l ____ ___ ___ --" o 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 k 97 fig. 12 bulk density vs. resistivity crossplot plotted on the linear scale. the oblique line is the position of d=o (discriminant analysis). points below this line (d=posi­ tive: star) = source rocks; points above this line (d=negative: rectangle) = non source rock. the analysis is from an area of the middle adriatic ridge. fig. ! 3 m/n(z) four component cl"ossploi consisting of it combination of sonic tran­ sil lime , bulk density, compensated neu­ tron porosity and z=u 238 • the oblique line is the position of d=o (discriminant analysis). points below this line (d=posi­ tive: star) = source rocks; points above this line (d=negative: rectangle) = noll source rock. the analyses are from an area of the middle adriatic ridge (after yulama. 1994). fig. 14 a/k(z) four component crosspiot comprising combination of sonic transit time, bulk density , compensated neutron porosity and z=u~ ·>f\ . the oblique line is the position of d=o (discriminant analy­ sis). points below this line (d=positive: star) = souree rocks: points above this line (d=negative: rectangle) = non soltrce rock. the analysis is from an area of the middle adriatic ridge. 98 .. typel r=0.5 900 . ines-i ¢ ~ irma-' 0 ~ irma-i 0 0 irma·' -¢u irma-' 0 bll suzana-l 0 , inga-l • u ~ type ii m ~ 500 @ ~ ~ ~ r= 1.5 400 450 500 tmax °c fig. 15 kerogen iype and maturity of pliocene source rocks of tile middle adriatic ridge. figures 714 and 19 show kith, cn/den/z, (z=u238 ), l'>,1rt(rmll), pb/rt(rmll), min and a/k crossplots. the diversity of well log parameters produces a characteris tic and dist inguishable four point star feature on the spiderweb diagram. it is also possible to defi ne this as a litho-logging unit (jancikovic et ai. , 1988; vulama, 1991 , 1993, 1994). the spec ific example related to the source rocks of the irma gas field is pre­ sented on fig. 17. the typical geophysical parameters for the source rock recogn ition of irma gas fi e ld are clearly visible on the complex diagrams of figs. 3,4 and 17. the cross plots krrh showed that the main clay min­ erai is illite together with some mica (illite and mica are struc turally very si mi lar) and mixed components of var­ ious clay minerals (fig. 7). the source rocks of th is clay mineral are alum inum and potassium rich rocks which can be found in the hinterland of the middle adriatic ridge, as wel! as volcan ic rocks of pliocene and plcistoccne age (tarj-kovacic, 1995; mile­ tic & lugovic, 1996). 5. statistical analysis statistical analysis was applied in order to empha­ size the simple classification rules to distinguish source geologia croatica 50/1 gamma ray corelation profile (b-b') 0 e inoa-l mes-! 1rma_2 irma_i 1rma-4 irma-3 sljz..l j-22i1 on·' j-23i1 i p , i i i t h ~ t ~ ! r " 1 ~ t r£f i l t f r ,; t ;; \ .7.. t 1 ~ 0 , ~ 0 t ! i f r , f f r ;; ,f 0 t ! ,'c' , t l } t: "{ n ( { 0 0 r < f ~ ( 0 f 0 ; 0 0 "a" reservoire ~ 0 0 ) ~ 0 0 fig. 16 gamma ray composile log response of lhc middle adriatic ridge source rocks. rocks from non-sourcc rocks, based on quantitative well log parameters. the source rock well log parameters were logged for the pliocene organic rich deposits of the irma gas field. non-source rocks parameters were logged a t intervals above and below the source rocks. these para­ meters were divided into two classes based on the geo­ chemical analyses of rock sampl es: c lass i = source rock; class 2 = non-source rock. geochemical analyses are based on the results of the pyrolys is, vitrinite reflec­ tion values and the carboni zati on degree of paly­ nomorphs. discriminant analys is (pseudoregression scheme) was performed in the statist ical analysis (davis, 1973; meyer & nederlof, 1984; vulama, 1991, 1993, 1994) figs. 9, ii and 13, tables 1 and 2. geo­ physical parameters (formation resistivity, bul k densi ty , sonic transit time, neutron apparent porosity and natural radioactivity urani um ) are used as coordinates to locate the classified rocks. to separate c lass i from class 2 it is necessary to establish the discriminant line. the main characteristic of the discriminant fu ilction is that the distance between the average values of class i and class 2 pro­ jections is maximal when the distance between the points inside a class is reducing. t he pseudoregression method means adding the appropriate value "y" to each class: vubma: pliocene source rocks, miocene reservoir rocks and origin of the gas accumulation .. description sample size source rock non-source rock misclassification separation of class means in pooled standard deviation class 1 mean class 1 stand. dev. class 2 mean class 2 stand. dev. coefficients ' : beta "0"2 beta("m") beta("n") beta sonic ("a") beta density ("0") beta resistivity shales only (middle adriatic ridge) min 217 100 117 6.6 1.2 0.64 1.44 0.76 0.26 2.24 3.71 6.31 99 all lithologies (middle adriatic ridge, sava & drava depression) air d/r 177 177 92 92 84 84 8.9 10.4 1.33 1.17 0.79 0.69 1.09 0.71 0.98 0.57 0.87 1.18 -1 7.86 -5.33 1.21 19.36 8.33 -1.46 'llb!c i res ult s of di scriminant analysis. results are tabulated for different well log combinations (after vulama, 1994) : "m " = sonic transit time vs. bulk -density: "n" = apparent neutron porosity vs. bulk-density; "a" = sonic transit lime (in logw ).ls/ft); "0" = bulk -den sity (in 10g io g/eillj) : "r" = resistivity at 24°c (inlog,o olnnm). legend: 1 all beta coeffi cients of discrim inam fu nctions are statislic.llly significum; 2 beta "0" is the intercept. a typical equation ixlsed on: min is: 0 =2.24-6.309'n+3.706-m. (midd le adriat ic ridge). air is: d=17.866+8.338-log(ac)+ 1.2 131og( rt) (m idd le adriat ic ridge, e, nw and sw part of drava depress ion, middl e part of say:! depression). oir is: 0 =-5 .326+ 19.366· log(oen)-1.461 '(rt) (middle adriatic ridge, e, nw and sw pari of drava depress ion, middl e part of sava depress ion). middle adriatic ridge source rocks description a/k min air d/r sample size 315 315 315 315 source rock 200 200 200 200 non source rock 115 115 11 5 115 misclassification 3.2 6.6 7.9 8.1 mean x 0.8358 0.7167 2.5195 2.51 mean y 1.4066 0.6012 127.1564 1.9710 slope -2.3156 1.2220 -8.4487 0.09829 intercept (beta ' ) 3.3421 -0.2746 t 48.4436 1.7234 r2 -0.7615 0.9663 0.2491 0.3409 dx/dy 0.4264 -0.8189 0.11880 -10.153 x * intercept 1.433 0.2254 17.592 -17.493 table 2 result s of di scriminant ana lyses (middl e adriatic ridge source rocks only). legend : 1 all l3eta coeffi cients arc statistically sig nificant ; "a"= bul k-density vs. apparent neutron porosity; uk" = sonic tl',:lil s it tim e vs. apparent neutron porosity. 100 a) or 150 c~ " p" 1041n '" u~ b) gr , at 2!lq r , t, ·n " ~ p" c~ sp fig. 17 spiderweb (min./max.) (a) and average stee ped (b) logs responses and c-organic content of the m iddle adriatic r idge source rocks. n2 / (n i + n2) for class i, ancl -n i / (n i n2) for class 2, where n 1 = source rock and n2 = non-source rock. next, the regression upon vari able "x" is per­ formed, usi ng one of the multiplying regressive pro­ grams. the resu lting "pseudoregression" is the discrim­ inant function, where "z" is replaced by "0". the anal ys is resu lt s in the linear value of the dis­ c riminant "0", w hil e the param ete rs can also be expressed in loga rit hms if the range of their values is wide. the lyp ica l ca lculation of the crossp lot .1t/r t (fig. 9) is as fo llows: d = -17.866 + 8.33s' log,o'ac + 1.21 3' log lo' rt(24°c), for the crossp lot llt/pb (fig. ii ): d = -5.326 + 19.366' log,u'den 1.461 ' logiort(24°c), and for the c rossplot min (fig. 13): d = 2.24 6.309' n+3.706'm the well log and geochemical parameters arc equa­ li ons fo r calcu lati ng "d", if "d" is posit ive then the rock is most probably a source rock; if "d" is negative, then the rock is a non-source rock; and if d ;:: 0, the case is considered to be undefined (figs. l3, 14 and 19). irma-2 o gr 125 q.. __ !'.i) __ .?~ \ ( ~, < > / .... , ) i ) j i j i \ i "' tn o 0> o o geologi;l croa,ica 50/1 middle adriatic ridge "a" reservoire o rilm 15 o rild 15 -------------------.----. ----,' rmin • ~ rmax fig. 18 pclmcability estim ation from resistiv ity gradient in miocene rese rvoir rocks of the irma gas fie ld (a consistent rehill with lab­ oratory analysis), analytical resu lls show that such a quali fication has certain sta ti stical e rrors. the discriminant analys is method used for source rock c lassi fication showed the average error between 3.2 10.4% (tables i and 2). errors in classification can be caused by: i. poor correlati on between geochemical and petro­ physical data caused by the presence of shallow in terbeds. one shallow intcrbcd of the nonsource rock, sampled for geochem ical analysis can give fa lse data and vice versa (this case occurred during the geochemical analyses of gas field irm a). 2. heavy minerals in high concen tration , c.g. pyrite, can cause low readings of bulk density and dim inish the resistivi ty. 3. in unconsolidated rocks, the physical contrast bctween organic rich and organic poor layers is min­ imal , espec ially in the case of low conccntrations of organic matter. 4. 1n very dense and compact rocks (with high veloci ty or the son ic wavc), the measurements of the bulk dcns ity can be inaccurate. vijlnmn: pliocene source rocks, miocene reservoir rocks and origin ofille g;)s accumulation ... 101 zmax 0.9 irma-i 35 source rocks zmin 0 0.8 0.7 source rocks (¢--) 0.6 m -¢-¢i 8' -¢,e; 0.5 -¢;~ -¢0.4 -¢-¢0.3 0.2 -¢-¢--¢-¢-¢d=-o.27+1.22*n-o.82*m 0.1 0.4 0.5 0.6 0.7 0.8 0.9 1.1 1.2 1.3 fig. 19 m/n(z) rour component crossplot consisting of a combination 0(" sonic lran­ sit time, bulk density, compensated neu­ iron porosity and z=u 138 . the oblique line is the position or 0=0 (di scriminant analysis). point s below this line (d=posi­ tive: star) = so urce rocks: points above thi s line (d=negative: rectangle) = non source rock. the analysis is from irm a­ i well (middle adriatic ridge). n 6. vertical permeability from the formation r esistivity gradient vertical pe1l11eability can be calculated from the dif­ ference in the val ue of the formation resistivity in the transition water/gas zone according to the schlumberg­ er formula: k ~ eca x 2.3/(pw-p,,))', where c = schlumberger constant = 20, a = basic gradi­ ent of fo rmation resistivity ca ~ t.r/6d x l/ro6r ~ di[­ ference bet ween max. and min. res istivity in the gradi­ ent , where: t.d ~ different ial depth (in feet), ro ~ 100% water satu rated resistivity; ro = fr x rw, where: rw = formation water resis tivity; fr = formation factor; pw = water density in formation conditions; ph = ch density in formation cond itions). [-or irm a 2 (fig. 18) this translates as: '" ~ 22%, r w ~ 1.8, l'r ~ 15.3, ro ~ 2.75 ohmm, t.d ~ 1580 m 1578.5 m ~ 1.5 m x 3.28 ~ 4.9 n, 6r ~ 10 4 ~ 6 ohmm, a ~ 0.44, pw p" ~ 1.02 0.0407 ~ 0.98, kavg. ~ 21.4 x 10 ' ~m2. evaluated vertical permeability should on ly be con­ sidered for the transit ion zone (t-zone, fig. 5) and can not be app lied to the entire interval. we cou ld calculate permeab ility by resistivity gradi ent only when the t­ zone is clearly visible on the res istivity logs. 7. correlation with geochemical analyses interpretation of well logging data and crossplot s for these source rocks showed good correlat ion with geochemical analyses. logging data show very low val­ ues of formation resistiv ity of 1.5-4 ohmlti , that, accordi ng 10 ex ploration performed e lsewhere (vula­ ma, 199 1, 1993,1994) indi catcd thc immaturity o[ these source rocks. geochemical analyses confirmed this low malurity, but also suggest ed that these source rocks produced biogenic gas (on irma-l well iso tope c and i-i depletion showed o" c -73%0 and od 188 (-) 192%0, and chromatogram giving >98.5% of methane). based 011 statistical discriminant analysis erossplots, 6l/r, p"lr, a/kcz) and m/n(z) were computcd, and the processed geophysical parameters (p", rt , rmll, lll' <pn' gr u23~) were used as coordinates for the clas­ sification. the measured parameters were divided into two classes according to the geochemical rock sample analysis: class 1 source rocks; c lass 2 non-source rocks. the followin g me thods were used for correlation: pyrolys is, vitrinite re flectance and degree of paly­ nomorph carbonization. if one of these did not meet the source rock criteria, this point was automatically classi­ fied as noll-source rock, or at least listed as unidentified if the point was on the function (d~o) itself (figs. 9, 11 and 13). the correlation of geophysical and geochemical sur­ veys determined the following parameters as being typ­ ical for these source rocks: gr ~ 55-125 api, u2j8 ~ 525 ppm , rt ~ 1.5-4 ohml11, 6 , ~ 75-170 i1s/fl (x 0.306 115/m), pb ~ 1.6-1.9 g/c m', q,n~ 33-39%, sp ~ -44 (-) -56 m v, corg. ~ 0.43-3 .23 %, kith ~ illite. they are classified as kerogene type iii and ii (figs. 4,5,8,15-17). characteristic geophysical parameters of irma miocene gas reservoir rocks are: $ = 22%, rw = 0.18, m ~ 1.8, fr ~ 15.3, ro ~ 2.75 ohmm, k avg. ~ 2l.4 x 10-3 ~m2 8. discussion and interpretation of the probable gas accumulation process in the irma field previous work in this area indi cated th e irm a gas accumulation originated by migralion processes from 102 deepe r parts of the basin from older miocene and mesozoic sed im ents (kadija at ai., 1991; kadija, 1992). the origin and source of this gas was not clearly defined. vertical migration processes which led to gas accumulation in miocene reservoirs were also involved. these papers summari zed drilling, logging and geo­ chemical analysis data which indicated very short downward migrat ion pathways for biogenic gas pro­ duced by low maturity pliocene source rocks overlying the m iocene reservoirs, which were result of overpres­ sure. all the geophysical parameters proved that the basal part of the pliocene shales is rich in organic matter. it is a source rock confirmed by geochemi cal analysis. at first, the survey of the induction resistivity loggi ng tool (difl) was misleading because these curves did not show resist ivity increasing in the source rock zone, although resis tivity is an important indicator of a source rock. however, using the micro-resistivity curvc (mll) the problem can be resolved (figs. 3 and 4). the organ­ ic matter within the shales occurs as laminae, and could not have been detected by the low reso lution (d1fl) wire logging tool. the mll curve clearly shows the th in lam ination of the source rock and e lectric anisotropy (figs. 3 and 4). very low formation resistiv­ ity val ues (1.5 4 ohmm) indicate the immaturity of this source rock (vulama, 1991 , 1993, 1994). in the sou rce rock zone, overlying the messinian calcarenites, during the drilling of inna-i, a gas show was recognized at depth of 1520 m (7%; 1.7% c,) and at 1530 m (40%; 18% c,), and also in the irma-2 well at 1588 m. the shales above source rock zone also rep­ resent a very good seal. geochemical analysis proved that this was an immature source rock with the possibil­ ity of biogenic gas production (vulama, 1991). in the irm ai well the overpressure zone (:1: log) was confirmed in the overlaying pliocene and quater­ nary shal es . the basal section of these shales is the source rock ( 1445 1543 m). this zone is also clearly vis ible on the 10lal transit time curve (,6.[) and interval velocity curve (ltv i), according to the deviation from the noimal compaction trend of ihe hydrostatic pressure (fig. 6). the ,6.[ increase is the result of water trapped within the shales. the overpressure zone is also clearly indicated on the pb curve where the dev iation from the normal compaction trend occurs. curve ,6.[ and pb shows that the overpressure zone begins at about 1260 m. the hydrocarbons migrate (and fluids in general ) in the ovcrprcssure zone toward the lower pressure zone (magara, 1978). under hydros tatic conditions migr­ ation trends are upward and sideward s. in the irma field, where overlayi ng shales were overpressured, the migration trend is downward to the zone of lower pres­ sure in the calcarenites and sandstones of the messin­ ian unconformity, where gas accumulated. consider also that the capi llary pressure in the reservo ir rocks (especially in sandstone) is lower than in the imperme­ able non-reservoir rocks. geologi<l croat ica 50/1 geochemical analyses proved that the gas of the irma field is methane (up to 99.4%) of biogenic origin, and that it was generated fro m type iii-ii kerogene (fig. 12). mattavelli & novelli (1988) point out that 80% of all gas fields in italy contain gas of biogenic and/or diagcnetic origin (most of these fields are in the adriatic off-shore), while 20% contain gas gcnerated by thermal degradation of organic matter. the existence of thin laminated source rocks of plio-pleis tocene age is also documented and it is assumed thal the primary migration s of the biogenic gas were short and that migration was connected to the more porous parts of the source rocks (mattavelli & novelli, 1988). it is also suggested by the sp curve and gas shows on figs. 4 and 5. in the irma field there is direct contact between the source rock producing biogenic gas and the calcarenites and sandstones of messinian unconformity as the favor­ able reservoir (figs. 3-5) and there is an ovcrpressure zone. the gas from those source rocks probably migrat­ ed downward into the miocene calcarenites and sand­ stones. it can also be assumed that parlial fracturing of source rocks occurred in the contact zones and gas migrated through these fractures. in the north-east part of the area gas shows have been observed in shallower sediments (quaterna ry) above the carbonate platform (wells: inga-l, j-8, 123/1 and 11n-l ; fig. 2). gas migrations in these locations are vertical (through fault's zones kadija, 1992), but there is no vertical migration in the south-west area (irma gas field). during drilling and logging overpres­ sured zones were not indicated in north-east area and the pliocene (source rock) is usually missing (figs. 2 and 3). 9. conclusion the resu lts of geophysica l, geochem ical and geo­ logical investigations indicate the presence of source rocks of pliocene age in the area of the middle adriatic ridge. these were immature for oil and gas generat ion by thermal degradation, but they were capable of pro­ ducing biogenic gas. the geological conditions (organic ri ch overpres­ sured shales/silty shales bearing the organic matter) and structural-tectonic setting (sealing normal fau lt ) of the source rocks, indicate a short downward migration gas pathway between the porous fractured pliocene source rocks and underlying miocene calcarenites and sand­ stoncs rescrvoir. the correlation of gas recove red during drilling from source rocks and from the gas of reservoir irma ("au) and the laboratory results also indicate the origin of the gas from the overlying pliocene source rocks. vularna : pliocene source rocks. miocene reservoir rocks and origin or the gas accumulation ... loj acknowledgments i would likc to thank dr. gyorgy pogacsas for his helpful adv ises and comments on manuscript. spe­ cial thanks gocs to dr. losipa velic for hers always very precious comments and critic ism. also thank to vlasta tari, m.sc., for her comments on manuscript. for preparing the english man uscript thanks also to borka vucinic and to katiea m. krpina and z. budanovic [or technical support. this investigation was approved and supported thanks to ina-naftaplin oil company. 10. references da vis , j.c. (1973): statistics and data analysis iii geology.john wiley and sons, ncw york, 550 p. fertl, w.h. & chilingarian, g.v. (1988): total organic carbon content determined from wcll logs.­ spe 1562, 61st annu.tech.conl, 407-419, hous­ ton. fertl, w.h. & chllingarian, g.v. (1990): hydrocarbon resorce evaluation in the woodford shale using welllogs.j. pet. sci. eng., 4,347-357. hernitz, z., velic, l. & baric, g. (1995): origin of the hydrocarbons in the eastern part of the drava depression (eastern croatia).gcol. croat., 48/1, 87-95. jancikovic, b., vulama, i. & jungwirth, m. (1988): nove spoznajc 0 dubokim naslagama dravske potoline na temelju karotaznih mjerenja.­ dit, 23, 11-23, zagreb. kadija, n. (1992): stratigrafsko-tektonski odnosi plinonosn ih scdimenata u jugoistocnom dijelu padskc depresije.unpublished m.se. thesis, uni­ vers ity of zagreb, 7 1p. kadila, n., durn, '1'., zugec, n. & tomic, b. (1991): possibility of collecting hydrocarbons in carbonate sediments of the irma-explorat ion area.­ in: velic, i. & vlahovic, i. (cds.): second international symposium on the adriatic carbonate platform, zadar, abstracts, 48, zagreb. mattaveli , l. & novelli, l. (1988): geochem­ ist ry and habitat or natural gases in italy.org. geoehem., 13, 113. magara, k. (1978): compaction and fluid migra­ tion.elsevier scientific, new york, 392 p. meyer, b.l. & nederlof, m.h. (1984): identifi­ cation of source rocks on wireline logs by density/ resistivity and sonic transit time / resistivity cross­ plots.aapg buletin, 68,121-129. miletic, d. & lugovic, b. (1996): pliocene vul­ caniclastic sed iments in the croatian adriatic off­ shore region (dri ll -ho le kruna-i).in: drobne, k., go rican, s. & kotnik, b. (cds.): interna­ tional workshop postojna 1996: the role of impact processes in the gcological and biological evolution of planet earth. 52-53, ljubljana. prelogovic, e. & kranlec, v. ( 1983): geoloski razvitak jadranskog mora.pol11orski zbornik, 21, 387-405, rijeka. schmoker, j.w. (1981): determination o[ organic matter content of appalachian devonian shales from gamma-ray logs.aapg buletin, 65, 12851298. schmoker, l.w. & hester, t.e. (1990): forma­ tion resistivity as an indicator of oil generation-bak­ en formation of north dakota and woodford shale ofoklahoma.the log analyst, 31/3,1-9. tar! kovacic, v. (1995): razvoj pliocenskih 1 pleistocenskih naslaga sjevernog i srednjeg jadrana karotazni markeri i korclacija.in: vlahovic, i., velic, i. & sparica, m. (cds.): first croatian geological congres, opatija, proceedings, 2, 609612, zagreb. vulama, i. (1991): source rock definition on the basis of well logging.unpublished m.sc. thesis, university of zagreb, 131 p. vulama, i. (1993): proejena maticnih stijena na temclju karotaznih mjercnja u busotinama.nafta­ plin, iii, 19-39, zagreb. vulama, i. (1994): source rock potential of the east­ ern drava depression and some othcr source rock localitics in croatia as evaluated from well log data.geol. croat. 47/2, 205-214, zagreb. manuscript received november 4, 1996. revised manuscript accepted april 28,1997. 104 geologia croatica 50/1 geol. croat. 49/2 1359 -361 1 zagreb 1996 in memoriam mr sc. eugen krkalo (1942 1996) eugcn krkal0 , the head of the department of min­ erai resources of the lnstitute of geology, died on the 7th or august, j 996 in zagreb . devoted to his research, premature death removed our colleague as his scientific career came to fruition. eugen graduated from the fac­ ully of mining, geology and petroleum engineering in zagreb in 1967. from j969 he was employed by our inst itute, working for the first five years in the research group for mineral resources of the dalmatian area. this provided the basic experience which he later utilised independently in solving morc specific assignments and tasks in the field or mining geology. 1975 saw the beginning o f his many years geological experience in slavonia and moslavina which encompassed tackling the problellls of various mineral sources such as: quartz sand, building and dimension stone, tuff, zeolite, graph ite, clay, coal and other. krkalo was also an active participant of numerous scientific conventions, both in our coulltry and abroad, and he particularly distin­ gu ished himself at the first croatian geological con­ gress in opatija (1995). his contribution to croatian geology is of immeasurable vallie, and far exceeds his hundred plus professional papers and fifteen published articles. nenadano i prerano, dana 7. kolovoza 1996. godine, nakon kratke i teske bolesti preminuo je li zagrebu ml'. eugen krka!o, predstojnik zavoda za minera lne siro­ vine tl in slilulu za geoloska istrazivanja. u tom je trenutku iz /lase sredine nepovratno nestao cijenjeni kolega, uspjesan i priznat rukovoditelj niza znanslvc­ noistrazivackih projekata, a isto tako suprug i otac skladne obitclji. prerana smrt zadesi la je kolegu eugena (za veliki broj prijatelja i suradn ika geno) u zrelolll dobu znanstvenoistrazivackog rada, kada je zelio i bio spreman pribliziti se zenitu svoje karijere. nazalost, zla illll je suelb ina isto tako onemogucila ispunjenje obi­ tcljskih i roditeljskih obveza. magistar eugen krkalo rod en je j 3. veljace j 942. goeline u zagrebll. djetinjstvo i mladenacko doba proveo.ie ll zlatnoj ciolini zavicajne pozege. akadcmski obrazovan, nas sugracianin, i nakon svih nasih zajedni­ ckih zagrebackih godina, bio je i oslao ponosn i slavonac. diplomiravsi na smjeru rudnickc geo logijc rudarsko -geolosko-naftnog fakulteta u zagrebu, gospodin eugen krkalo zaposlio sc 1969. godine na nasem institutu u odjelu za mineralogiju, petrologiju i mineralnc sirovine. prvih pet godina rada proveo jc na terenima dal ­ maeije, za kojc se vrijcme osamostalio i usavrsio ii rjcshvanju specificnih zadataka u gcologiji fudnih lczisla. tim su istrazivanjima bile obuhvaccne pojave i [ezisla boksita, kvarcnih sedimenata, lllfova, gipsa i klaslila pcrma, arhitektonsko-gradcvinskog kamcna, kao i lezista tufa nedalcko livna, te boksita u liei. nakon 1975. god ine zapocinje za ellgena krkala visegodisnji znanstveni i istra7.ivacki rad na poelrucjll 360 slavonijc i moslavin c. uspjcs no jc rjcsavao brojne zadatkc, od regionalnog do dctaljnog karaktera. njego­ va su istrazi vanja obuhvatila brojne i raznovrsnc pojavc mineralnih si rovina, od njcmu poscb icc zanimljivih kvarcnih pijesaka, preko pojava kvarca i kvarcita , arhitcktonskog i tchnicko-gracicvinskog kamena, tufo­ va, zeo lita, grafita , valrosta lnih glina, do energelski h s irovi na (smedih ugljcna i lignita). sustavnim, sl1'­ pljivilll i upornim radom posebice je bio uspjdan u is trazivanj ima kvarcnih pijesaka, koja su rczultirala akli viranjcm ni za novih lezis ta: vranic , jagma-5, livadan i i vn linska, uz lezista precl otvaranjem: mokrcs, stefanac, novo sc lo i brandcl navedcna sll istra7.ivanja bila tcme lj iz kojcg j c us lij edila uspjcsna obrana magistarskog rada 0 kvarcnim pijescima lezista vrtlinska 1985. godine. vrij edn i i zapazc ni su takoder njegovi radovi 0 istrazivanj u turova i zco lil a lez ista poljanska, potom ic7.ista kvarcita radovanka, tc novija istrazivanja kvar­ ca, kvarcila i blokovi tog granita na papllku . .tos od 1974 . godine eugcll je aklivni sudionik bro­ jn ih znanstvenih skupova i kongresa u zcmlji i inozem­ stvll, sve do nj cgove posebice zapa zenc uloge na 1. hrvatskom geoloskolll kongresll proslc god inc ii opatiji. u njegovom znanstvcnoistrazivackolll raclu posebna i visoka priznanja dobi li su projckt kompleksno clefini1'anjc llkupnog resursnog poleneijala repllblike i-trvatgeologi:l cronlic:149/2 ske (1986-1990) , te program i uputc za izradll kane mineralnih sirovina i prognozne karle republike hrvalskc ( 1990). gocline 1992. preuzeo jc mjesto sera oeljela za min­ eralne si rovine i imenovan clan om upravnog mibara, a oel 1993. godine na dllznosti je prcdstojnika zavoda za mincralne sirovine. uz say navedeni visegodisnji znanstvcnoist raz ivacki rad, kao i brojllc poslovnc i obiteljskc obveze, uspio je izrad iti i svoju cloktorsku discrtacijll: lezisla ncogcll ­ skih kvarcnih pijesaka u rubnim pocirucjima slavonskih planina ciju uspjesnu obranu, nazalost, nije elocekao. nakon svega prethodno navecienog i nabrojcllog, a uz sto tinjak prog1'ama i 90 elaborata ii fondu lnstilut a za geoloska istrazivanja u zagrcbu, ie 15 publici1'anih radova, nit sveukllpnog radnog opllsa pokojnog kolcgc krkala nazalost je prerano i ilaprasno preki nllla , i to u trenlltkll njegovih maksimalnih zivotnih ambieija j sposobnost i. tu lez i sva te7.i na gllbitka eugena k1'kala iz nase sredine, kao kolege, su radnika i prijatc lja. nama dobro poznali eugcnovi ll spjcsni znanslvcno­ istrazivacki i strllcni rad ostaje neprojazna vrijednost loa hrvatsku geologijll . uvijek korektan i prisan oelnos prc­ ma sv im suracinicima vise nego dovoljno oerlava nje­ goy lik i karakler, koji od nas ne moze i ncce biti zabo­ ravljen. anlo gabrlc !11 i ... kl1lo r i~11l: eugcn kr ka lo popis oi3ja vljenih radov a i. jovi c, p. , s usnjara , a. & krka lo, e. ( ! 975) : kvarcnc sirovinc ii sr iirvatskoj.j. savjc~ tovanjc 0 kvarcnim sirovinam<l 1i jugoslaviji, 2 [-25, jajce. 2. krk a lo, e. & m utlc, r. ( 1978) : tufovi u nas iagama donjcg tanona u podrucju njezica kod slav onskc pozcgc (tuffs in lower tortonian depos it s of njczi r..: area ncar slavonska pozega, north cmatia). geol. vjesnik 30/2, 341 -350. 3. krk a lo , e. & s imunic, ai. ( 1979): geoloska g rada icz ista kvarcnog pijcska "vrani c" kod slav. pozegc (slavonija , sjc verna i-irvat ska) (geo log ic struc ture or the vrani c quart z sand depo sit near s lavonska paz-ega north croali a).geol. vjesnik , 3 1,2 19-227. 4. susn jara , a. , krkalo, e. , brau n, k. & niklcr , l. (1982) : istrazivanje mineralnih sirov­ ina u sr hrvat skoj od 1976. do 1981. godinc.­ geol. vjesnik, 35, 244-247 . 5. sca yn icar, s. , sca vi icar , b. & krkalo, c. ( 1982): analc im 1i polimiktnoj pe trografskoj aso­ e i.iac iji (juzno poclnozjc papuka sjevcrna hrvatska) (a nalcime in pol ymi el petrographi c associati o n ~ southern foot of papuk mount a in north croalia).­ x. ju bilarni kongrcs geologa jugos lav ije, zborn ik radova, 1, 401 -410, budva. 6. scavntcar, s. , krkalo, e. , sca vn icar, b. , ha lle, r. & t ibuas, d. ( 1982) : naslage s anal ­ c imom u poljanskoj (s lavon ija sjeverna i-irvatskn) (analcime bearing deposits in poljanska, slavonija, no nh ertl croati a) .rad jazu , 404, 137169, zagrcb. 7. pami c . j. , krkalo, e. & prohic , e. (1984) : granilne stijene sjeverozapadnog dije la moslavacke gore u sjcvernoj ilrvalskoj.gcologija razprave in pomeila, 27, 201 -2 12, ljubljana. 8. krkalo, e. ( 1985) : pronalazak i istrazivanje lezis l<-l kvarcnog pijeska "vrtlinska" kod cazme s posebnim osvrtom na koru troscnja granitnog masi­ va sjcverozapadnog oboclnog podrucja moslavackc go rc.magistarski rad , rudarsko-geolosko-naftni fakult et, prirodoslovno-matemat icki fakul lcl sveu­ cilisla u zagrebu, 138 p. 36 ! 9. krkalo , e. , galovic, i. & dr avec­ bra un, j. ( 1992): polencijalnosl geoloskih fo rma­ c ija s kvarcnim pijcscima u re publi c i hrval skoj. ­ simpozij 1ndu strij a nemetala 1i o bno vi i razv oju republike iirvat ske, zbornik radova, centar zn istrazivanjc i razvoj ncmctala, 29-38, zagreb. 10. bio ndic, b. , bukovac, j. & krkalo, e. (1992): uloga gcolog ijc li obnovi i razvoju r epub~ like hrvalske. simpozij 1nclu strija nemct ala u obnovi i razyoju repub like hrvatske, zbornik rado­ va, centar za istrazivanje i razvoj nemetala, 76-84, zagreb. ii. pamic, j. & krkalo, e. ( 1993): gcoloska zbir­ ka pranjevackog sclmostana u pozegi i kajo agjic.­ znanstvcni skup 0 kaji agjicli , i-lrvalska akademija znanosli i umje tnosti , ceillar za znan stvcni racl vinkovc i. 12. sinkovec, b. & krka lo, e. ( 1994): graphite depos it s from mt. psunj in si avo nia (northern croalia).geologia croatica, 47/1, 11 7~ 126. 13. krkalo, e. & pencinger , v. ( 1995) : miner­ a lne sirovine oto ka mljc ta. s impozij pri rodnc znacajke i drustve na valorizac ija otoka mlj e ta , pom ena, otok mlj e l, 4. 10. rujna 1995. eku loske lllonografije, 6, 1 4 7 ~ 156 , zagreb. 14. krkalo, e. , susnjara, a. , sca vnica r, b. & gabr ic, a. ( 1995) : jurski silie ij ski sedimenti iell1 cs kog racijcsa (maim) 1i daimhciji i li c i. i. hrvat ski geoloski kongres, opatija, 18.-21. 10.1995., zbornik radova, 1,32 1-326, zagreb. 15. sinkovec, b. & krkalo, e. ( 1995): potenei­ jalnost rudonosnih geoloskih formaeija republi kc hrvatske.1. l-lrvat ski gco loski kongrcs, opaiija , 18. -2 1.10. j 995. , zbornik radova , 2, 585 -590 , zagreb. 06 loncaric.indd planktic foraminiferal content in a mature agulhas eddy from the se atlantic: any influence on foraminiferal export fluxes? neven lončarić 1. introduction the oceanography of the southern part of the se atlantic is characterized by two prominent features: (1) the benguela current flowing northwards along the african continent, and (2) the inflow of the indian ocean water into the atlantic around the cape of good hope. the benguela upwelling system (18–34°s) is nowadays one of the four major eastern boundary current regions of the world oceans, distinguished by cold and nutrient rich water (peterson & stramma, 1991; shannon & nelson, 1996). in the southern cape basin (the area where the benguela current originates), the warm, salty agulhas current intrudes from the indian ocean (peterson & stramma, 1991). a greater part of the agulhas current water retrogrades back into the indian ocean, whereas a smaller part leaks into the se atlantic (lutjeharms & van ballegooyen, 1988). this occurs in the form of large scale eddies that on average 5 to 7 times per year enter the atlantic in the zone of agulhas retroflection (goñi et al., 1997; schouten et al., 2000). the agulhas eddies are anticlockwise rotating bodies that average 250 km in diameter and extend to a depth of 1000 m (lutjeharms, 1996; van aken et al., 2003). due to their rotational motion they are distinguished by an elevated surface relative to the surrounding ocean, traceable on satellite sea surface height (ssh) images (byrne et al., 1995). once formed, the agulhas eddies migrate northwards within the benguela current, gradually mixing with the surrounding water, losing heat and salinity. the decay of such a ring can take up to a few years, by the time they cross the central walvis ridge (schouten et al., 2000). this addition of warm and salty water to the south atlantic is an important element of the global thermohaline circulation (gordon, 1985, 1996; de ruijter et al., 1999) and one of the major controlling factors of the south atlantic heat and salt budget (lutjeharms, 1996; weijer et al., 1999). the effectiveness of the retroflection in generating warm eddies depends on the position of the subtropical front (de ruijter, 1982). it may be assumed that this front moves northwards during glacial periods (berger & wefer, 1996a), cutting off the supply of heat to the south atlantic with direct consequences for the north atlantic deep water formation (weijer et al., 2001). due to such a decisive role of this system in the glo geologia croatica 59/1 41–50 7 figs. 1 tab. zagreb 2006 key words: planktic foraminifera, southeast atlantic, agulhas eddies, interocean exchange, globorotalia menardii. royal netherlands institute for sea research (nioz), department of marine chemistry and geology, p.o. box 59, 1790 ab den burg, texel, the netherlands. correspondence address: aleja pomoraca 25/xiii, hr-10020 zagreb, croatia; e-mail: neven.loncaric@zg.t-com.hr. abstract the agulhas eddies, large-scale rings of warm salty water, occasionally intrude into the benguela current system from the indian ocean and progress northwards across the cape basin and the walvis ridge. this inter-ocean exchange of heat and salt along the cape of good hope is considered to play a crucial role for the global thermohaline circulation. yet, the modern faunal composition of mature eddies from the northern cape basin and walvis ridge was uninvestigated in spite of the global importance of the agulhas inflow, preventing firm micropalaeontological study of the palaeoceanographic variability of the ocean exchange in this area. this paper describes the composition of the modern planktic foraminiferal assemblages collected from a mature agulhas eddy when it entered into the northern benguela current system. the effect of the eddy’s gradual decay on the foraminiferal communities in the upper water column is specifically examined, using plankton tow and ctd-rosette profiles, obtained within and outside the ring. in addition, exported foraminiferal fluxes beneath the eddy were investigated in order to determine their impact on the accumulation assemblages as recorded in sediment traps moored near the sea floor and in the core-top sediment from a box corer. the examined mature eddy “w” was clearly evident on the satellite altimetry images by its elevated surface. it was distinguished from the surrounding ocean by a slightly higher salinity, deeper surface mixed layer and higher planktic foraminiferal standing stocks. similar to planktic foraminiferal fauna in freshly formed eddies from the agulhas retroflection, species such as globigerinoides trilobus s.l., globigerinoides ruber, orbulina universa, globigerinella siphonifera and globorotalia scitula dominated in the ring “w” assemblages. however, globorotalia menardii, a species previously believed to be characteristic for the agulhas leakage into the s. atlantic, was virtually absent in the eddy “w” fauna. also globorotaloides hexagona, a species endemic in indian ocean waters, was not found in the water column, in the export flux or underlying sediment. the february to july foraminiferal flux patterns recorded by the sediment traps mirror the february standing stocks from the water column. here in contrast, the core-top results show dominance of intermediate/cold water species that originate from the seasonal spring bloom. this signal prevails in sediment to the extent that any potential agulhas eddy signature in the sediment was overprinted. 42 geologia croatica 59/1 bal ocean circulation and assumed high variability on the glacial–interglacial scale, the influence of the agulhas eddies on the sedimentation patterns in the south cape basin was the subject of several palaeostudies (berger & wefer, 1996b; flores et al., 1999; chen et al., 2002; rau et al., 2002). recently peeters et al. (2004) studied the modern system and provided firm evidence for the characteristic foraminiferal signature of a freshly formed eddy that allowed documentation of the inter-ocean exchange dynamics for the last 500 kyrs from the sediments of the southern cape basin. although sea surface temperature anomalies of agulhas rings tend to disappear quickly (olson et al., 1992), satellite altimetry monitoring (e.g. topex/ poseidon) documented that approximately two thirds of the eddies formed at the agulhas retroflection cross over the northern cape basin and the central walvis ridge (e.g. garzoli & gordon, 1996; goñi et al., 1997; schouten et al., 2000). such older eddies within northern cape basin surface waters have never been a subject of in-situ ecological studies. therefore their faunal characteristics and the importance for sedimentation patterns are largely unknown. the purpose of this study is to determine for the first time the faunal and physical signature of a long-lived eddy and better understand the coupling between such oceanographic source signal in the water column and the exported flux directly below. 2. material and methods the area of the cape basin off southwestern africa has been monitored for spawning and decay of agulhas rings since 1992 using topex/poseidon satellite altimetry (gründlingh, 1995; goñi et al., 1997; schouten et al., 2000). aided by ssh images we sampled the centre of the long-lived eddy “w” in the northern cape basin during the first mixing of agulhas rings experiment (mare) expedition in february 2000 (fig. 1). depth-stratified plankton tows were collected in the centre of the eddy (154 p–06), at its edge (154 p–05), and outside in the surrounding ocean (cwr) (table 1; figs. 1 & 2). each station covered nine depth intervals from the upper 800 m of the water column. the plankton was collected using a hydrobios multinet system modified for oblique towing and equipped with 100 µm plankton nets (lončarić, 2005). at the same sites, the entire water column was profiled using a neill–brown ctd-rosette sampler (veth, 2000). in addition, two technicap pps5 sediment traps were moored 250 m above the sea floor, one below the centre of the eddy at site 06 (water depth 5036 m), and another outside the eddy at the cwr site (water depth 2700 m). the traps had a sampling area of 1 m2 and collected an integrated 6-months sample of pelagic particles settling to the sea floor. for processing of foraminiferal samples from traps and plankton tows, and the taxonomic determination, the procedure described in lončarić et al. (2005, 2006a, b) has been followed. the foraminiferal standing stocks are calculated following the method from lončarić (2005) and lončarić et al. fig. 1 sea surface altimetry image (topex/poseidon; positive anomaly in red, negative in blue) from february 18, 2000 and location of three sampling stations from this study. the centre of eddy “w” (marked by an arrow) was at the time of sampling (february 22, 2000) exactly at station 06. station coordinates [°] sampling technique lat. long. pl. tows ctd sed. trap box core cwr 27.0 s 3.9 e + + + + 05 28.8 s 6.3 e + + 06 29.2 s 8.2 e + + + table 1 position of the stations and sampling techniques applied in this study. 43lončarić: planktic foraminiferal content in a mature agulhas eddy... (2006a). in addition to the plankton tow, ctd-rosette and sediment trap sampling, we also recovered the bottom sediments using a box corer at the cwr site during the mare iii cruise (february 2001; station 174 p– 03/6). the sampling and processing of the box core and its stratigraphy are described in lončarić (2005). the results of the foraminiferal analysis from the uppermost 0.5 cm of the sediment are presented here. 3. the eddy “w” in october 1999 the agulhas eddy named “w” was one of the most prominent features on the sea surface height images of the cape basin (available at: http://ibis.grdl. noaa.gov/sat/hist/tp_products/topex.html). it was situated in the central cape basin, at the approximate latitude of cape town. during the austral spring and early summer it migrated northwards by approximately 5° latitude and lost its intensity. the ssh image of february 18, 2000 (fig. 1) was used for pinpointing station 06, in the centre of the ring. the eddy “w” remained at site 06 for approximately two weeks, and then migrated westwards over the walvis ridge. in may 2000 it disappeared from the ssh images. during april/may 2000 another smaller agulhas eddy was in the vicinity, south of site 06. however, this eddy disintegrated before fully reaching the site. although situated centrally within the “agulhas eddy corridor” (garzoli & gordon, 1996; schouten et al., 2000), the cwr site was not crossed by the fleeting eddies during the entire sediment trap sampling period (february–july 2000). the crucial assumption being made here is that ssh anomalies in the southeastern atlantic ocean are indeed agulhas rings (schouten et al., 2000). it has been shown without question that the gross ssh variability in the cape basin only arises from passing agulhas rings (garzoli & gordon, 1996; garzoli et al., 1996). in addition, e.g. van aken et al. (2003) have demonstrated by extensive seagoing hydrographic investigations, the relationship between topex/ poseidon ssh anomalies and in-situ measured properties of the rings. most of the time, the ssh position of the ring centre is within 50 km, or half a degree, of the fig. 2 location of the study sites with the regional bathymetry and hydrography. legend: boc – benguela oceanic current; bcc – benguela coastal current; sacg – south atlantic central gyre; ar – agulhas retroflection; e – agulhas eddies. map created by omc at www.aquarius.geomar.de. 44 geologia croatica 59/1 actual centre (schouten et al., 2000). seawifs satellite images of the surface chlorophyll-a concentration (lončarić, 2005; lončarić et al., 2006b) show that all stations sampled in this study were oligotrophic, outside the direct influence of the benguella upwelling at the time of the plankton towing. yet, tongues of nutrient-rich water spreading from the benguela upwelling zone did approach station 06 from july to september 2000 (lončarić et al., 2006b). 4. results 4.1. physical properties during plankton tow sampling and ctd-rosette profiling (february 22, 2000; station 06) the eddy “w” was situated in the northern cape basin. it was eminently distinguishable on the ssh image by its elevated surface (fig. 1). although clearly recognisable on the topex/poseidon satellite image, the ctd profiles taken in the centre of the eddy (station 06) and outside in the open ocean (cwr station) were similar (fig. 3). the similar temperature of the surface mixed layer (~22°c) and prominent deep fluorescence maximum at ~100 m characterised both profiles. in both cases the fluorescence maximum was below the surface mixed layer. the centre of the eddy differed from the surrounding water by ~0.1‰ higher salinity, deeper surface mixed layer (60 m in the ring vs. 35 m outside) and by a somewhat broader and stronger fluorescence maximum (fig. 3). 4.2. foraminiferal assemblages the foraminiferal concentration profiles in the upper 800 m of the water column collected by plankton tows fig. 3 temperature, fluorescence and salinity profiles for the upper 200 m of the water column measured by the ctdrosette sampler at three study sites from figs. 1 & 2. fig. 4 shell concentration of total planktic foraminifera sampled by plankton tows within eddy “w” (right panel) and in the surrounding oligotrophic gyre (left panel). numbers refer to the total foraminiferal shell standing stocks in the productive zone calculated following the method described in lončarić (2005) and lončarić et al. (2006a). 45lončarić: planktic foraminiferal content in a mature agulhas eddy... (figs. 4–6) were compared with the export fluxes from the sediment traps and the accumulation flux from the core top sediment (fig. 7). the selected stations represent the foraminiferal assemblages within the eddy (station 06) and the surrounding oligotrophic gyre (cwr station), respectively. in addition, quantitative analysis of the plankton tow samples was performed at station 05, situated at the moment of sampling at the eddy’s edge (fig. 1). 4.2.1. water column fauna in february 2000 the foraminiferal standing stock within the eddy “w” was more than two times higher than in the surrounding oligotrophic ocean (fig. 4). the highest total foraminiferal concentrations were restricted to the surface mixed layer (sml) at both stations. yet, within the eddy, the foraminiferal concentrations showed two maxima, one within the uppermost tow interval and another at the base of the sml. in contrast, by february 2000 the surrounding ocean was characterised by a shallow sml (fig. 3) and high foraminiferal concentrations were restricted to the uppermost 25 m (fig. 4). the standing stocks at both stations were dominated by tropical, shallow-dwelling species such as globigerinoides trilobus s.l. and globigerinoides ruber (figs. 5 & 7). orbulina universa, globigerinella siphonifera and fig. 5 shell concentration profiles of 10 major foraminiferal species from the plankton tows sampled within and outside eddy “w” given for the upper 400 m of the water column. species given in black belong to the typical agulhas leakage fauna (peeters et al., 2004). numbers refer to the standing stocks in the productive zone of the particular species calculated following the method from lončarić (2005) and lončarić et al. (2006a). 46 geologia croatica 59/1 globorotalia scitula were frequent only within the eddy and showed maximum concentrations in the subsurface. remarkably, the tropical globorotalia menardii was virtually absent within the eddy, while this species was the third most abundant in the surrounding ocean where it showed the second highest concentration in the uppermost tow interval. for the other species, deep-dwelling globorotalia truncatulinoides (sin) and globorotalia inflata showed similar concentrations and vertical distributions at both sites, whereas globigerinita glutinata and hastigerina pelagica were rare. quantitative analysis performed on the tow material collected at station 05 (fig. 1), showed significantly increased plankton standing stocks compared to not only the surrounding ocean, but also to the centre of the eddy (fig. 6). the concentration of organic matter was approximately 5 times higher, and the concentration of the particulate inorganic matter exceeded 15 to 45 times the values from the eddy and the surrounding area, respectively (fig. 6). 4.2.2. export fluxes the relative abundances of major species from the plankton tow and sediment trap assemblages were strikingly similar in spite of the long sampling interval of the traps, covering an integrated 6-month period from february to july 2000 (fig. 6). absence of coloured, opâque or fragmented foraminiferal tests at both trap sites and pronounced lunar cyclicity observed for fragile hastigerina pelagica at the cwr site (lončarić et al., 2005) testified to the accuracy of flux sampling and complete preservation of foraminiferal shells due to the ph buffered collecting cups (lončarić et al., 2006b) and relatively fast settling of specimens >150μm considered in this study (takahashi & bé, 1984). as in the water column standing stocks, the warm-water species g. trilobus s.l. and g. ruber also dominated the exported flux intercepted by the traps at both sites. the assemblages from the cwr site situated outside the eddy “w” were generally in agreement with the previously published results from the upper water column and surface sediment characteristic for the s. atlantic subtropical gyre (e.g. bé & tolderlund, 1971; niebler & gersonde, 1998; kemle-von mücke & hemleben, 1999). only minor differences between the plankton tow and sediment trap assemblages were manifested by the increased relative abundance in the export flux of g. siphonifera at the cwr site, and by the increased relative abundance of g. inflata, together with g. siphonifera at site 06, respectively. in contrast, o. universa and g. scitula showed higher relative abundance in the water column within the eddy “w” than in the export flux beneath. 4.2.3. core-top sediment assemblages since the water depth at site 06 (5036 m) is deeper than that of the calcite lysocline (i.e. the depth at which calcite becomes undersaturated or the level of the onset of carbonate dissolution) and the carbonate compensation depth (i.e. the depth below which the rate of calcite dissolution exceeds the rate of deposition) we sampled the sediment surface only at the shallow cwr site (2700 m). the 14c and 210pb analyses showed that the topmost sediment at the cwr site is modern in age and the mixing rates are very low (lončarić, 2005). the centennial average accumulation flux preserved in the walvis ridge sediment differed in foraminiferal assemblage from those in the export flux and standing stocks sampled at the same site. in contrast to the composition of the fauna in the water column standing stocks and in the sediment trap fluxes, which were dominated by g. trilobus s.l. and g. ruber, approximately one third of the normalised foraminiferal assemblage in the uppermost 0.5 cm of the sediment was composed of g. inflata (fig. 7). also some other secondary species within the water column and export flux assemblages such as sinistral g. truncatulinoides, g. glutinata and g. scitula showed a significant increase in the relative abundance within the surface sediment. in addition to the conventional enumeration of foraminiferal species, which considers on average 300 shells per sample, more than 5000 foraminiferal shells from the sieve size fraction >150 µm in the cwr surface sediment were fig. 6 concentration of organic and particulate inorganic matter larger than 100 µm from the plankton tows sampled at three study sites from figs. 1 & 2. the organic matter is calculated as dry bulk weight minus weight of the ashed residue. 47lončarić: planktic foraminiferal content in a mature agulhas eddy... randomly analysed in search for globorotaloides hexagona, a species endemic to the indian ocean. yet, this species was neither recognised in the sediment sample, nor in the traps or plankton tows. 5. discussion the physical properties of a young, freshly formed eddy from the agulhas retroflection zone in the southern cape basin have been recently studied in situ by van aken et al. (2003). this eddy was distinguished from the surrounding water by higher temperature and salinity values, and a deeper surface mixed layer. the foraminiferal assemblages of a young agulhas eddy were characterized by high standing stocks and the dominance of tropical–subtropical species (peeters et al., 2004). the most dominant among 10 characteristic agulhas leakage species were g. trilobus s.l., g. ruber and g. siphonifera (peeters et al., 2004). fig. 7 relative abundance of 9 major foraminiferal species normalised to 100%, sampled within and outside eddy “w”, in the water column (february plankton tows), export flux (integrated february to july sediment traps) and accumulation flux (core top sediment). the assemblages characteristic for a young agulhas eddy from the southern cape basin are given for comparison (bottom right – after peeters et al., 2004). 48 geologia croatica 59/1 due to a strong air–sea interaction (olson et al., 1992), the positive sea surface temperature anomaly disappeared by the time eddy “w” reached the northern cape basin. yet, the ring was still clearly visible on ssh images (fig. 1). although the eddy lost some of its original physical and faunal signatures during its migration, that took more than a year from the indian to the atlantic ocean, several characteristics were still recognizable. it was distinguished from the surrounding ocean by a deeper surface mixed layer, higher salinity and higher foraminiferal standing stocks (figs. 3 & 4). the foraminiferal assemblages were dominated by the same species (i.e. g. trilobus s.l., g. ruber and g. siphonifera), characteristic of a freshly formed ring (fig. 7). however, the contrast between the physical and faunal characteristics of eddy “w” and the surrounding oligotrophic water of the subtropical gyre was weak (fig. 5). it is mostly difficult therefore to clearly identify a mature eddy based only on foraminiferal assemblages, without additional support from the satellite-derived sea surface altimetry, though this is not due to faunal changes. in a number of palaeostudies on cape basin sediments, g. menardii was attributed to have originated in the indian ocean and its presence in the sediment record was interpreted as indicative for the “open cape valve” (berger & wefer, 1996b; rau et al., 2002), i.e. an interconnection between the indian and atlantic ocean. our results suggest that this species does not belong to the typical mature ring fauna. instead in the ring assemblages, an order of magnitude higher standing stock of g. menardii has been found in the adjacent subtropical gyre (fig. 5). in addition, this species does not appear in the modern, freshly formed agulhas eddies in relative abundances higher than 2% (peeters et al., 2004, supplementary information s5). therefore it is more likely that during interglacials, when ocean fronts shifted southward (berger & wefer, 1996a), this species re-seeded the cape basin from the subtropical atlantic, rather than from the indian ocean (see fig. 3 from berger & wefer, 1996b). this implies that the reappearance of g. menardii in the sediment records of the cape basin, and in particular in its northern part, cannot be directly interpreted as evidence for the opening and closing of the “cape valve”. surprisingly high concentrations of organic and particulate inorganic matter were recorded at station 05, situated at the edge of the eddy “w” (fig. 6). these concentrations were not only higher than in the surrounding oligotrophic ocean, but also compared to the centre of the eddy, suggesting a significantly increased productivity and high faunal standing stocks. the flow velocities of the rotating eddy increase with the distance from its centre to the inner edge, where they drop due to the friction with the surrounding water. the velocities are highest at the top of the thermocline and decrease with depth (van aken et al., 2003). therefore, drastically increased standing stocks recorded at station 05 may be the result of an “upwelling type” process in the turbulent zone at the interface between the eddy and the surrounding water. such a mixing process could introduce nutrients from the subsurface into the surface mixed layer, enhancing productivity in the otherwise predominantly oligotrophic environment. the integrated february–july export fluxes recorded by the sediment traps at stations cwr and 06 mirror to a large extent the water column standing stocks from february 2000 (fig. 7). this suggests stable conditions in the productive zone during the entire period of trap sampling. the increased dominance of g. inflata in the deposition fluxes, coupled with decreasing foraminiferal diversity and abundance of the warm water species, accompany the transition from oligotrophic to mesotrophic conditions along the west–east benguela trophic gradient (lončarić, 2005; lončarić et al., 2006b). therefore increased export fluxes of g. inflata suggest increased productivity, in particular at site 06 situated ca. 200 km closer to the benguela upwelling zone. such enhanced productivity occurred probably at the end of the sampling period when this site encountered the filaments of nutrient-rich water spreading from the benguela upwelling zone or, more likely, subsurface nutrients became available due to the wind-induced winter deepening of the surface mixed layer (lončarić et al., 2006b). alternatively, the higher relative abundance of o. universa, g. scitula and g. ruber in the february water column of the same site appear related to the passing eddy. the dominance of g. inflata and distinct assemblages of the cwr core-top sediment, in contrast to the february plankton tow and february to july sediment trap assemblages (fig. 7), indicate a strong overprint by the seasonal bloom. approximately 25% of the annual flux in this area is deposited during the short, but prominent austral spring maximum in october (lončarić et al., 2006b). this seasonal event dilutes the already very weak indian ocean signal that remained in the mature eddy and makes it untraceable in the fossil record. in all studied samples specimens of g. hexagona were absent. this species is endemic to the indian ocean waters, but present in low abundance in the zone of agulhas retroflection and in the freshly formed agulhas rings (peeters et al., 2004). therefore, the fingerprint of indian ocean inflow cannot be firmly traced by the foraminiferal assemblages in the water column and surface sediments of the northern cape basin and the central walvis ridge. acknowledgements i thank the captains, crews and shipboard scientific parties of r/v pelagia (the netherlands) and r/v agulhas (republic of south africa) for their assistance during the mare cruises. g.-j. brummer (nioz) is thanked for the helpful comments on an earlier version of this paper. reviews by d. bogner and one anony49lončarić: planktic foraminiferal content in a mature agulhas eddy... mous referee helped to improve the manuscript. this work was financially supported by the dutch ministry of education, arts and science within the netherlands– bremen oceanography (nebroc) program. the mare program (mixing of agulhas rings experiment) was financed by the clivarnet project of the netherlands organization for scientific research (nwo–alw). 6. references bé, a.w.h. & tolderlund, d.s. (1971): distribution and ecology of living planktonic foraminifera in surface waters of the atlantic and indian oceans.– in: riedel, w.r. (ed.): the micropaleontology of the oceans. cambridge university press, cambridge, 105–149. berger, w.h. & wefer, g. (1996a): central themes of south atlantic circulation.– in: wefer, g., berger, w.h., siedler, g. & webb, d.j. (eds.): the south atlantic: past and present circulation. springer-verlag, berlin, heidelberg, 1–11. berger, w.h. & wefer, g. (1996b): expeditions into the past: paleoceanographic studies in the south atlantic.– in: wefer, g., berger, w.h., siedler, g. & webb, d.j. (eds.): the south atlantic: past and present circulation. springer-verlag, berlin, heidelberg, 363–410. byrne, d.a., gordon, a.l. & haxby, w.f. (1995): agulhas eddies: a synoptic view using geosat erm data.– journal of physical oceanography, 25/5, 902–917. chen, m.-t., chang, y.-p., chang, c.-c., wang, l.w., wang, c.-h. & yu, e.-f. (2002): late quaternary sea-surface temperature variations in the southeast atlantic: a planktic foraminifer faunal record of the past 600000 yr (images ii md962085).– marine geology, 180/1–4, 163–181. de ruijter, w.p.m. (1982): asymptotic analysis of the agulhas and brazil current systems.– journal of physical oceanography, 12/4, 361–373. de ruijter, w.p.m., biastoch, a., drijfhout, s.s., lutjeharms, j.r.e., matano, r.p., pichevin, t., van leeuwen, p.j. & weijer, w. (1999): indian–atlantic interocean exchange: dynamics, estimation and impact.– journal of geophysical research, 104/c9, 20885–20910. flores, j.-a., gersonde, r. & sierro, f.j. (1999): pleistocene fluctuations in the agulhas current retroflection based on the calcareous plankton record.– marine micropaleontology, 37, 1–22. garzoli, s.l. & gordon, a.l. (1996): origins and variability of the benguela current.– journal of geophysical research, 101/c1, 897–906. garzoli, s.l., gordon, a.l., kamenkovich, v., pillsbury, d. & duncombe rae, c. (1996): variability and sources of the southeastern atlantic circulation.– journal of marine research, 54/6, 1039–1071. goñi, g.j., garzoli, s.l., roubicek, a.j., olson, d.b. & brown, o.b. (1997): agulhas ring dynamics from topex/poseidon satellite altimeter data.– journal of marine research, 55/5, 861–883. gordon, a.l. (1985): indian–atlantic transfer of thermocline water at the agulhas retroflection.– science, 227/4690, 1030–1033. gordon, a.l. (1996): communication between oceans.– nature, 382/6590, 399–400. gründlingh, m.l. (1995): tracking eddies in the southeast atlantic and southwest indian oceans with topex/ poseidon.– journal of geophysical research, 100/c12, 24977–24986. kemle-von mücke, s. & hemleben, c. (1999): foraminifera.– in: boltovskoy, d. (ed.): south atlantic zooplankton. backhuys publishers, leiden, 43–73. lončarić, n. (2005): planktic foraminiferal response to changing se atlantic oceanography.– ph.d. thesis, vrije universiteit amsterdam, 184 p. available from: https:// dare.ubvu.vu.nl/bitstream/1871/9103/1/6943.pdf lončarić, n., brummer, g.-j.a. & kroon, d. (2005): lunar cycles and seasonal variations in deposition fluxes of planktic foraminiferal shell carbonate to the deep south atlantic.– deep-sea research i, 52/7, 1175–1186. lončarić, n., peeters, f.j.c., brummer, g.-j.a. & kroon, d. (2006a): oxygen isotope ecology of recent planktic foraminifera at the central walvis ridge (se atlantic).– paleoceanography, 21, pa3009, doi:10.1029/ 2005pa001207. lončarić, n., van iperen, j.m., kroon, d. & brummer, g.-j.a. (2006b): seasonal export and sediment preservation of diatom, foraminiferal and biogenic mass fluxes in a trophic gradient across the se atlantic.– progress in oceanography, in press. lutjeharms, j.r.e. (1996): the exchange of water between the south indian and south atlantic oceans.– in: wefer, g., berger, w.h., siedler, g. & webb, d.j. (eds.): the south atlantic: past and present circulation. springer-verlag, berlin, heidelberg, 125–162. lutjeharms, j.r.e. & van ballegooyen, r.c. (1988): the retroflection of the agulhas current.– journal of physical oceanography, 18/11, 1570–1583. niebler, h.-s. & gersonde, r. (1998): a planktic foraminiferal transfer function for the southern south atlantic ocean.– marine micropaleontology, 34, 213–234. olson, d.b., fine, r.a. & gordon, a.l. (1992): convective modifications of water masses in the agulhas.– deep-sea research i, 39/1a, 163–181. peeters, f.j.c., acheson, r., brummer, g.-j.a., de ruijter, w.p.m., schneider, r., ganssen, g., ufkes, e. & kroon, d. (2004): vigorous exchange between the indian and atlantic oceans at the end of the past five glacial periods.– nature, 430/7000, 661–665, doi:10.1038/nature02785. peterson, r.g. & stramma, l. (1991): upper-level circulation in the south atlantic ocean.– progress in oceanography, 26/1, 1–73. rau, a.j., rogers, j., lutjeharms, j.r.e., giraudeau, j., lee-thorp, j.a., chen, m.-t. & waelbroeck, c. (2002): a 450 kyr record of hydrological conditions on the western agulhas bank slope, south of africa.– marine geology, 180, 183–201. 50 geologia croatica 59/1 schouten, m.w., de ruijter, w.p.m., van leeuwen, p.j. & lutjeharms, j.r.e. (2000): translation, decay and splitting of agulhas rings in the southeastern atlantic ocean.– journal of geophysical research, 105/ c9, 21913–21925. shannon, l.v. & nelson, g. (1996): the benguela: large scale features and processes and system variability.– in: wefer, g., berger, w.h., siedler, g. & webb, d.j. (eds.): the south atlantic: past and present circulation. springer-verlag, berlin, heidelberg, 163–210. takahashi, k. & bé, a.w. (1984): planktonic foraminifera: factors controlling sinking speed.– deep-sea research i, 31/12a, 1477–1500. van aken, h.m., van veldhoven, a.k., veth, c., de ruijter, w.p.m., van leeuwen, p.j., drijfhout, s.s., whittle, c.p. & rouault, m. (2003): observations of a young agulhas ring, astrid, during mare in march 2000.– deep-sea research ii, 50/1, 167–195. veth, c. (2000): rv pelagia cruise report: cruise 64pe155, project mare-1, mixing of agulhas rings experiment.– nioz, texel, 42 p. weijer, w., de ruijter, w.p.m., dijkstra, h.a. & van leeuwen, p.j. (1999): impact of interbasin exchange on the atlantic overturning circulation.– journal of physical oceanography, 29/9, 2266–2284. weijer, w., de ruijter, w.p.m. & dijkstra, h.a. (2001): stability of the atlantic overturning circulation: competition between bering strait freshwater flux and agulhas heat and salt sources.– journal of physical oceanography, 31/8, 2385–2402. manuscript received march 21, 2006. revised manuscript accepted june 9, 2006. geol. croat. 49/2 243 246 4 figs. zagreb 1996 scientific note dry gas injection for miscible displacement on zutica oil field tvanka juttner key words: gas injection, mi scibility condit ion, enhanced recovery, di sp lacement, vaporizing gas drive, multiple conlacl abstract by the process of gas injec tion under mi scible conditions, th e (alai oil recovery also includes vaporized hydrocarbons from the residual immobile oil, in addition (0 (he oil produced by direct dis ­ placement. the process is complex and involves ihe innucnce of the interaction of extracted hydrocarbons and in-situ oil at the displace­ ment fronl. therefore, the final oil recovery under miscible cond it ions is higher than th e "conventionally" displaced oil. methods of calcu­ lating multiple contacts miscibility with an equation of state (eos) determine the miscibility condit ions by simula tion processes as a vaporizing gas drivc or cond ensi ng gas drive. the aim of this study was 10 dctcmlinc a degree of miscibility. i. introduction when a fluid is injected into a reservoir to displace oil towards the production well, oil recovery is not completc. one method to improve recovery is to reduce or suppress the interfacial tension between the oil and injeetcd nuid. this happens when injected fluid, hydro­ carbon gases for example (dry natural gas, mainly methanc, carbon -dioxide) are miscible with oil (bla­ ckwell cl al.. 1959; benham cl al.. 1960; stal­ kup. 1984). 2. methods and results the aim of this research was to simulate the process or oil production in the zutica field by maintaining reservoir pressure, and to define process characteristics (miscibility or immiscibility condit ions). to simulate the process, a unidimcntional rcservoir sim ulator comp3 was uscd (scienti fic software intercomp). a 9-component system was required in the formulat ion of fluid composition (adjusted to pr £os). it was also assumed that the pore space contains only sat urated oil faculty of mining, geology and petroleum engineering , un iversity of zagrcb, picroltijeva 6, hrioooo zagreb, croatia. proceedings kljucne njecl: utiskivanje puna, uvjeti mtjcsanja, povecanje iscrpka, istiskivanj e, otparavanje u plin­ sku fazu, visekontaktni proces. sazetak pri proccsima uti skivanja plina ukupni iscrpak nafte ukljllcllje osim !laftc proizvedene izravnim istiskivanjem i ugljikovodikc otparene iz zaostale, nepokrelnc nafte. mehanizam procesa je slo~.cn i obuhvaea cfckte interakcijc olparcnih ugljikovodika i nafte na frontll ist iskivanja. zato je konacni iscrpak nane liz proccs mijcsanja veei od "konvcncionalno" isti sllulc i olparene naftc. metodc racunanja visekontaktllog olparavanja s nckom od jed­ liadzbi stanja odrcduju uvjcte mijdanja simulacijom proccsa; meha­ nizmom olparavanja iii mchanizmom kondenzllcijc. cilj si mulacijc procesa proizvodnje nanc polja zutica rczimom podrzavanja slojnog tlaka bio jc odrcdivanje karaktcra proccsa, ij. stupnja priblil,avanja uvjctima mijcsanja izral.enog velicinom iscrpka naftc. (the cr iterion for iluid mobility calculated by multiple contact vaporization), and does not consider either the influcnce of petrophysical heterogeneities of the reser­ voir rock, or the viscous fingering of iluid. in fact, only the thermodynamic aspect of the process is investigated. the sequence of calculations is correlated with the practical procedure of oil production which consists of: i. gas injeclion (slobod & koch. 1963; cau­ dle & dyes, [958) into a reservoir until a certain pressure is attained, and 2. maintenance of constant reservoir pressure with a given valuc of oil production. part of the injected dry gas is dissolved in the reservoir oil and the cons(> q uenccs are: • increasing oil volume (oil-swell); • changes in phase composition, density and viscosity of oil; • changes in composition and density of equi librium gas phase. changes of these properties of zutica oil calculated for various prcssures ranging from the initial saturation pressure pbi :::: 128.5 bar up to 200 bars are shown in fi g. l in this particular case, injected dry gas is poorly dis­ solved in already saturated oil and swelling of oil is 6%, while oil density decreases by 3% from 0.687 10 0.665 g/cm3 . simulation of the dynamics of displacement pro244 geologia croatica 49/2 1.08 ! 0.70 , i v-----y density r i • ~ _________ swem,g facw / 1.06 0.69 "e ~ .~r '0 '0 > 1.04 " • ~ 0.68 0.67 / 15 ?: ." 0 0 u 1.02 / 1.00 125 150 175 gas injection pressure (bar) cess at set constant pressure or gas injection has already been performed unde r var ious pressure va lues. typical curves of oil recovery versus volume of injected gas are shown in fig. 2. oil recovery is not a distinct function of inj ection pressure , therefore the oil recovery at a pressure or 135 bars (pressure close to actual reservoir condi ti ons) is a little lower than oil recovery at 180 bars pressure. gas injection of one pore volume (p.y.) at a pressure of 135 bar gave a recovery of 5 1 %, while at a pressure of 180 bar the recovery is 55% of the original oil in place. a practical method of defining a characteristic mul­ tiple contact miscibility between injected fluid and oil is the "slim-tube" test from which the minimum misci ­ bi lit y press ure (mmp) was de termined . accord ing to 100 ~v 200 0.66 0.65 fig. 1 changes in properties of reservoir oi l during gas injec­ tion (after jultner, 1995) . the c riterion (yelling & metcalfe, 1980) the minimum miscibility pressure (mmp) is that particular gas inject ion pressure when 1.2 p.v. of injected gas dis­ p laced ovcr 90 % of present oil. results of the "slim­ tube" tes t are shown in fi g. 3 whi ch showcs that the miscible conditions in the sys tern (saturated oil zutica methane, respectively dry natural gas), can be achieved only after application of very high pressure (mmp of a sys tem is 500 bar). in other words, in oil product ion from the zutica fi e ld, th e regime of press ure mainte­ nance should make modest contri butions by the mecha­ nism of multiple contact vaporization to oil displace­ ment, since in the interval of rea l applicable press ures of gas injection the process will proceed undcr immi sci­ bl e conditions. 80 i 0------0 injection pressure", 135 bar i ................. , ................. i i · ··············· ······ · ···~ ,: "60 e g ;j! " 0 > 0 40 f-.... u ~ '0 20 c-.. .. o o ......................... 0.5 i 0----0 injection pressure", 180 bar i 1.0 1.5 amount of gas injection (p.v.) fig. 2 oil recovery by multiple 2.0 conlac\ process caner jut­ tner, 1995). ju1tner: dry gas injection for miscible displacement on zut ica oil field 245 100 i -----~ ~ ..------/ :....----80 v / :> 0: 60 / / /' v ;f. '" • > 0 u ~ '0 40 i il recovery at 20 o 100 200 300 gas injection pressure (bar) quantitative dynamic changes of composition with dependence on quantity of injected gas is shown in fig. 4. the enrichment of dry gas with for example ethane is about 80% at the first contact and aboltt50% at the 16th contact (which equals the total injected volume from 0.8 p.v.). it must be noted that these data relate to processes of gas injection into saturated oil. the gas cap in the reservoir has not been considered. in this par­ ticular process, composition of lhe existing gas cap affects the phase equilibria and final composition of the produced gas phase. 3, conclusion by processes of gas injecl ion into a reservoir, the composition of fluids in the area near the critical point ;f. 15 100 80 e 60 o 15 c .2 1i e 40 • u c o u 20 o i i r-r-i -ia d r-1 1 i i ii i i 11 c, co, components '. at injected gas i 4dc 500 fig. 3 determination of minimum miscibili ty pressure ( mmp) ("s li me-tube" test) (afte r jot­ tner, 1995). distinctly diffe r from the composition of the original reservoir fluid. therefore it is necessary to create a good model of a fluid from 9 to 15 components adjust­ ed with one equations of state (eos). to produce more oil, the pressure in the reservoir must be maintained by injecting another fluid. oil dis­ placement in the zutica oil field by maintaning reser­ voir pressure by gas injection at an actual pressure of 130 bar occurs under immisci ble conditions in accor­ dance with the expected phase behaviour of a methane­ oil system, because the minimum miscibility pressure (mmp) of injected gas in reservoir oil , determined by the "slim-tube" test, is about 500 bar. if the process should be performed at higher pressure (up to maxi­ mum possible reservoir pressure of 200 bar), it cannot be expected to produce a greater contribution to misci10 injected gas i after 1st contact afte r 15th contact r-8 ...... 6 . . . .. . 4 2 iii . o ;f. 15 e j " " £ 15 c 0 ~ ~ e • u c 0 u fig. 4 composition of equilibrium gas (after joltner, 1995). 246 bility displacement in the lotal production. at the pre­ sent production regime, injection of the dry gas leads to enrichment of gas phase by multiple contact vaporiza­ tion of liglll hydrocarbons. low volumes of methane dissolve in the oil in place, so changes in the propci1ics of the sa turated oil arc indistinct. the contribution of multiple contact mechanism of hydrocarbon vaporizing in \olal oil displacement is negligible. acknowledgment thi s work was supported in part by ministry of sci­ ence and technology of the repub lic of croatia (pro­ ject 2-16-230: " improvement of hydrocarbon recovery by gas injection processes"), gt:ologia croilticii 49/2 4. references benham, a.l., dowden, w.e. & kunzman , w.j. (1960): miscible fluid displacement prediction of miseibility. trans. aime, 219, 219-237. blackwell, r.l., rayne, 1.r. & terry, w.m . (1959): factors influencing the e fficiency of misci­ ble displacement.trans. aime, 216, 1-8. caudle, b.h. & dyes, a.b . (1958): improving mis­ cible displacement by gas-water injection.trans. aime, 213, 281 -284. luttner, l. (1995): proces optimalization for recov­ ery improvement by gas recycl ing in oil reservoir with gas-cap .unpublished phd thesis, [-'acuity of mining, geology and petroleum engineering, uni­ versity of zagreb, 122p. slobod, r.l. & koch, h.a. l r. (1963): high pres­ sure gas injection-mehanism of recovery increase.­ drill. and prod. prac., 20, 82-96. stalkup, f.l. lr. (1984): miscible dispiacement.­ monograph series, l. h. doherty memorial funf. of aime spe, dallas, 8, 2-135. yelling, w.f. & metcalfe, r.s. (1980): deter­ mination and prediction of co2 mmp. 1. petr. techn., 32/1,160-168. geol. croat. 50/2 1 157160 1 zagreb 1997 professor herak's contribution to regional geology and geotectonics josip benic ', ivan blaskovic' and vladimir tomic' a deep insight into the s trati g raphy ancl reg ional g~o logy of many countries from several continents, as well as acquaintance with geotectonical references and experience from many detailed fie ld explorations of "c rucial cases" gave herak an original altitude and unique way o r approaching geotec tonic problems. although g lobal tectonics was never actually his pr imary scient ifi c objective, some practica l problems persuaded il c rak of the necessity 10 understand the structural relationships of any studied area. the first scientific contributions of global tectonics ex tend to the carly days of herak's career. apml [rom <in acquaintance with stratigraphy, practical problem s !110slly of a hydrogeolog ical nature required ex plana­ ti on of the struc tural re lationships in the in ves tigat ed a reas. thus, as early as 1959, in his paper on the geolo­ gy and hydrogeology of the island of hvar, the under­ ground water system of thc island was explained with the aid o f a del imi ted anticline. only a year later, by d isclosin g the middle triassic anticline in the ric ica po lje he e luc id ated the mechani sm of sinking and upwelling of the local ground waters (herak , 1960). apart from its scienti fic contributi on, the latter was also important in planni ng the accumulation basi n of the obrovac electri c plant. it seems that the significant moment for herak 's geotecton ic inc lination occured in 196 1, when he stud­ ied geologica l relationships in the upper course of the kupa river, with the purpose or inves tigating possibili ­ ties for the accumu lation of water. it was thcn that her­ ak and hi s coworkers published the paper "new ele­ ments of tec tonics in the upper course of the kupa riv­ e r". in stead of being autochthonous with palaeozoic an ti c linal corcs, they di scovered tha t both palaeozoic nnd triassic sediments lay allochthonously over juras­ sic carbonate rocks. [-ie ex posed hi s vi si on or tectonic upheavals in the dinaricles at the international congress in bar in 1971. one should not ove rl ook the sc ientific paper 0 11 the tectonic in te rpretation of evapor ites of the 1 ins!i lu!e of geology. s<lchsova 2, p.o. box 268. iir -loooo zagreb, em;liia. 2 pactdly of mining, geol ogy and pelro leum engineering, un iversily of zagreb. pierollijeva 6, hr · i 0000 zagreb, croatia. .1 departmen! of geology and pa taeo ntology. facu hy of science, university o f zagreb. ul. kralja zvoni mi ra s, hr -ioooo zagreb, cro;l! ia. dalmatian zagora, ei ther (herak, 1973). he late r re interpreted this idea in hi s capital work on tectonics publi shed in 1986, in which the thrusts from the north­ eas t had been subs tituted with continental s ubduc ti on from the southwest, that is, with subduction of the adri ­ atic beneath the dinaric plate, taking into consideration his observations from earlier work. from then on , her­ ak was no longer sa tisfi ed with the ilumerous geotecto­ nic models that describe the struc ture of the dinarides based on the theory of geosynclines with double oroge­ ny. he unde rstood that something must be radi call y changed in the basic concepts of dinaric geotcctonisrn. painstakingly col lecting the fi e ld data, analysing them, and reeva luat ing all accessible elata, parti cul arly in the area of gorski kotar, velcbit mountain and lika, herak discovered the ex istence of allochthonous tectonics in the reg ions form erly treated entire ly as autochthonous in origin. he reconstructed the mechanism or movement with two cardina l iss ues: a) the cause of mo veme nt must be sought muc h deeper ("subc ru sta lly '"), while subduction is direc ted toward the north east ane! obstructed from withi n the cru stal zone; b) the intensity of allochthony increases with the depth. this point of view is bas ically differe nt from co­ existing opinion s, bccause all geotectonic concepts about the structure of the dinarides held that the thrust­ ing was directed [rom the northeast toward southwes t. all this was exposed as early as 1980 in hi s first pio­ neering work based on mobilis ti e ideas: "the system of nappes betwcen vrbovsko and delnice in gorski kolar (hrvatska)" (herak , 1980). today, the re is no doubt that herak had already presupposed the continental sub­ duction (a-subduction) which, a lthough under diffe rent name, would later im print the tec toni cs or the din ar­ ides. since 1980 herak has been directing hi s sc ientifi c curiosi ty increasingly to the e lucidation o f th e geotec­ tonic problems of the dinarides. although subduct ions on the ocean marg ins were in those days the prim ary this paper was presented at the scientific meeting dedicated to the 80th anniversary of the life of professor milan herak, held on march 5th, 1997 in zagreb foclis of scien tific interes t, he presupposed simultane­ ous subduct ions among separate parts of the cot incnlal crust. having realized that an ample conceptual diversity desc ribing the teclon ics of the dinarides can not be reduced to some already recognized common model, he preferred to announce his own idea of regional tecton­ ics. exploring the available literature he recogn ized that the concept of plate tectonics had displaced completely the classic concept o[ fixism all over the world. there­ fore he tried \0 discover new geotectonic definitions for our croat ian regions as well as abroad . by 1986, herak brou ght to light a new concept of genesis and structure of the dinarides ("a new concept for the geotectonics of the dinaricles") (herak, 1986), suggesting an alter­ nati vc for the two princ ipal geotectonic units, mostl y called the "outer" and "inner dinarides", and supplant ­ ing them by the four palaeoambi ental and pa laeody­ namic belts. these are reall y four independent palaeo­ geographic units with appointed significance of corre­ sponding paleodynamic units in the period of develop­ ment and structural formation. this is precisely where interdependence has been observed between reg ional geo logy, which is a basis for the definition of palaeo­ geog raphic unit s, on one side, and geotectonics on the other, as far as similar behaviour of the newly promoted units in the stages of structural formation is concerned . ex tending continuously from the peloponnese to the southern alps these palaeogeographic units arc aligned as fo [l ows: "ad ri atic um ", "epiadriaticum", " dinar­ icum ", and "s upradinari cum", each with its spec iric attri butes. they occupy mutually allochthonou s pos i­ tions brought about by continental subductions of cer­ tain units under others. reinterpreting all access ibl e data from nulllerous localit ies and correlating the re lief of the moho discontinui ty with tectonic configurat ion, herak in his subsequent works substantiated his earlier conclu sion concerning pronounced illobilism as a rea­ son for th e origin of allochthonous structures in the broader area of the dinaridcs. this idea gradually pre­ vailed throu gh the tectonic literature, resulting in the reex amination of many previous theories about the structure of locally confined areas, and sometimes their correc ti on. the widespread geological community sometimes cons iders he rak 's ideas daring and revolutionary, but onl y because the whole concept represents the fru it of longlast ing re fl ections and thought on the basis of bonding theory and cx perience. the scientific results he has accomp lished were promptly uti lized in practi ce, whi le, in turn , he subsequentl y used applied geological results to supplement and improve the fundam ental geolog ica[ scientific principles. geologia croatica 50/2 references herak , m. ( 1959): prilog geolog iji i hidrogeo logiji otoka hvara (zur geologie und hyd rogeologie der 1nsel hvar).geol vjesn ik, 12 (1958), 135148. herak , m. ( 1960): geologija gracackog polja u liei (geologie des karst polje von gracac in def lika, kroatien).geol vjesnik, 13 ( 1959), 3 1-56. herak, m., bolanic, l., sikic, d. & magda­ lenic, a. (196 1): novi clement i tektonike u pod­ rucju gornjeg toka rijeke kupe (neuc elcmente der tektonik im gebiet des oberlaufs des kupa-flus­ ses).gcol vjesnik, 14 (1960), 245-251. herak, m. ( 1971): beitrag zur rekon struktion der orogenetischen dynamik in def din ariden kroati ­ ens.i simp. 0 orog. [az3m<l u prosto ru ev rope, beograd-bm (1970), 35-40, beograd. herak, m. (1973): some teetonieal problems or eva­ porit ic area in the dinarides of croat ia (neki tek ton­ ski problemi pojasa s evaporitim a u dinaridimh hrvatske).geol vjesnik, 26 (1972), 29-40. herak, m. (1980): sustav navlaka izmedu vrbovskog i delnica u gorskom koihru l-irvatska (the nappc­ s·ystem between vrbovsko and delnice in gorski kotar croatia).acta geol, 10/2, 35-5 1, zagreb. herak, m. (1986): a new concept or geotectonics of the dinarides (nova koneepcij a geotekton ike dinar­ ida).acta geol, 16/1 , 1-42, zagreb. herak, m. (199 1): dinaridi mobi lis tick i osvrt no genezll i struktllru (dinarides mobili s tic view or the genesis and stmcture). acta geol, 21/2, 35-117, zagreb. benic. lll:lskovic & tomie: llerak: regional geology and geotectonics l.it) doprinos prof. heraka regionalnoj geologiji i geotektonici dobro poznavanje stratigrafije i regiona!ne geo!ogi­ .ie mnogih zemalja na vise kontinenata, poznavanjc lite­ rature 0 geotektonici, te iskustvo s brojni h terenskih detaljnih istrazivanja "klj ucnih terena", omogucili su profcsor li m. hcraku original an pristup pri rjdavanju gcotcktonskih problema. lako mu sira tektonika svojedobno i nij e bila u prvom planli njcgovog znanst venog intcresa, pojedini prakticni zadaci su ga uvjeri!i u nuznost poznavanja strukturnih odnosa istrazivanih terena. prvi znanstven i doprinosi iz sire tektonike sezu u m!adc dane profesora heraka. prakticni zadaci vezani uglavnom uz hidrogeolosku problematiku trazili sll, liz poznavanjc stratigrafije, i jjesavanjc strukturnih odnosa istrazivanih tcrena. tako nalazimo vee 1959. godinc u znanstven01l1 radu 0 geologiji i hidrogeologiji otoka hvara da uz poilloc utvrdene antik li na!e objasnjava podze1l111e vode otoka, a slijedece godine u ricickom polju otkrivanjclll srednjotrijaske antiklinale objasnjava mehanizam ponornih i izvorisnih voda, sto .ie uz zllan­ stvcni doprinos bi lo vrlo va7.110 i za projektiranje aku­ mulacijskog bazena hidroclektrane obrovac. cini se da je znacajan trenutak za geotektonsko usmjcrcnjc bila 1961. godi na pri proucavanju gco loskih odl1osa ii gornjcm toku rijeke kupe u cilju odredivanj a mogucilosti akumuliranja vode, kada prof. herak i sura­ dnici objavljlljll rczll llate ii radu "novi clementi tek­ lonike ii podrllcjll gornjeg toka rijcke kupe". umjesto alltohtonije s paleozojskim jezgram<1 antik li nala, utvr­ dili su da su i palcozojskc i trijaske naslagc alohtone na jurskim karbonatnilll naslagama. slijcdi niz radova vezan na stratigrariju i hidrogeologiju, da bi 197 i. na meclunaroclnolll si mpoziju ii boru izlozio svoje videnjc tektonskih prollljena u dinaridima. ne smije se presko­ citi ni 1973. godine publicirani znanstveni racl 0 tekton­ skoj intcrpretaeiji cvaporita dalmatinske zagorc, koji u svol11 kapita lllol11 tektonskol11 radu 1986. gocline rein­ terpretira zamijenivsi kretanja sa sjeveroistoka kon ti­ ncntalno1l1 subdukeijom s jugozapada, tj. podvlaccnjem j\drijatika pod dinarik uz uvazavanje svojih zapazanja iz starijeg rada. od laela m. heraka vise ne zaelovo­ ijavaju brojni geotektonski modeli gracle dinarida bazi­ rani na teoriji geosinklinala s dvostrllkilll orogenom . shvatio.ie ela se u osnovnim poimanjima geotektonike dinarida mora ncsto iz korijena mijenjati. strpljivim prikupjjanjcm tcrenske faklografije i njihovom anali­ zom, te revidiranjem postojccih podataka, prvens tveno u podrucju gorskog kotara, velebita i like, otkriva prislllnost alohtol1e tektonike u podrucjima koja sll do lada tretirana iskljucivo kao autohtona. rekonstruirao .ie mehanizam kretanja, gdjc su bitna dva zakljucka: a) uzrok kretanja treba lraziti dllbljc ("subkrustalno"), podvlacenje .ie prema sjeveroistoku uz otpore u krllstal­ nom dijelu; b) intcnzitcl a lohtonij c poveeava se od povrsine prema dubini. takav prist up .ie dijametralno suprotan dotadasnj im shvaeanjima, jer se ii svim geotektonskim koncepcija­ illa 0 grad i dinarida smatralo da su kretanja bila ad sjcvcroistoka prema jugozapadu. sve .ie to receno u njc­ govom prvolll (pionirskom) radu baziranom na l11obi­ list ickoj osnovi vee 1980. god.: "sllstav navlaka izmedu vrbovskog i delnica u gorskol11 kotaru (hrvatska)". citajuei danas taj rad jasno nam je cia .ie profcsor herak pretpostavio kontinenlalnu subdukciju (a-subdukciju), iako .ie tada nije tako nazvao, a koja ce kasnije obiljeziti tektoniku dinarida. svoj zllanstveni interes m. herak .ie od tada svc vise usl11jeravao na rjesavanje geotcktonskih problema dinarida. iako se u to vrijcmc pre tezito govori 0 sub­ dukeijama na rubovima oceana (13-subdukcije), u dina­ ridima pretpostavlja medusobne subdukcijske procese dijelova kontinentalne kore. uvidjevsi da vcliku razl1ol ikost ideja 0 tektonskoj gradi dinarida ne moze svcsti na neki poznati zaje­ dnicki mode l, te cia takve interpretacije nemaju rcalnu potvrdu u tcrenu, od lucio sc za svoju viziju 0 tektonskoj gradi toga prostora. prollcavajuci aktuall1u litcraturu uvidio je da koncepeija 0 tektoniei ploca posvuda u sv i­ jetu preuzima pojozaj klasicnih koncepeija fiksizma, te jc zato na tim osnovama pokusao naei nova geotekwn­ ska rjesenja za nas hrvatski prost or i s ire. i konacno 1986. god inc profesor herak iznosi novu koneepciju 0 gcnczi i gradi dinarida ("a new concept or geotecto­ nics of the dinarides"), gdje predjaze zamjenu dviju glavnih gcotektonskih jediniea, koje se najcesce nazi ­ vaju "vanjski" i "unutrasnji dinaridi", s cetiri paleoam­ bijentalna i paleodinamska pojasa. to sll zapravo celiri izdvojenc pa!cogeografske jedinice kojima je clat znacaj pa leodinamskih jcdiniea u razdoblju razvoja i slruk­ turnog formiranja. 1 upravo ovdje se vidi povczanost regionalne gcologije, kao os nove odrcdivanja palco­ geografskih jedinica i geotektonike u smislu priblizno slicnog ponasanja tih jediniea u razama rormiranja struktura. te se jedinice kontin ui rano pruzaju od pelo­ poncza do juznih alpa. to su: "adrijatik" , "ep iadrija­ tik" , "dinarik" i "supradinarik", a odlikuju se nekim spccificnim znacajkama. mcdllsobno sll ii alohtonim polozajima izazvanim kontinentalnim subdukcijama jednih jedinica pod druge. u svojim kasnuim radovima m. herak reinlerpretacijom dosaciasnjih poslojecih podataka s brojnih lokaliteta i korclacijom izmcclu re!je­ fa mohoroviciceva di skontinlliteta i tektonske grade ",,, potvrduje svoj raniji zakljucak 0 izrazitom mobilizmu kao uzrocniku alohtonih struktura u sircm poctrucju dillaricla. ideja postupno, al i sigufi10 ulazi u nasu tek­ tonsku literaluru, trazcc i prcispitivanje mnogih dosa­ dasnjih shvacanja struktura uzc omedenih terena, u cilju uzajamnog oplodivanja, pa i korekcija. u prebogalom i razllovrsnom znanstvenom raclu profcsora hcraka, geotektonski radovi postaju u zadnjih ijcl)lvgld i..-'v" ' i<";" _ivi.'.. lo-ak godina zacudujucom brzinol11 po opsegu i dubini uiaienja u problematiku srcdisnji intcrcs profcsora. samo za siru gcoiosku javnost to su smjeli i revolu ­ ciallami patezi, jcr sve je to p lod dugogodisnjih razmi­ sljanja i sazrijevanja ideja na osnovi spajanja znanosti i prakse, gdje znanstvcnc rczuitatc izravno primjcnjujc u praksi, a s prakticnim geoloskim rezultalima nadopun ­ java i korigira [undamentalnu geolosku znanost. geol. croat. 50/2 i l43 l46 1 1 zagreb 1997 academician milan herak's main contribution to palaeontology branko sokac', zlatan bajraktarevic2 and zlata jurisic-polsak' the main contribut ion of herak's palaeontological research carried out over a long period of time, began during his early career in the geological-palaeontologi­ cal museum in zagreb between 1943 and 1952. there­ fore his first publications concerned the field of palae­ ontology. within that scientific discipline herak made a significant contribution to the analysis of triassic cal­ careolls sponges from the "syconcs" group (herak, [943,1944). he investigated and presented the mor­ phological "characters" of five genera, and particularly those species where, on newly discovered material, he recognized some new features. he also established a new genus and species o/igop/ag/a cal"ll/ca . all previ­ ously known forms and their distribution were the sub­ ject of this herak's paper with special emphasis on the vertical distribution and lithogenesis of the group. from a lithogenetic point, herak highlights the genus ambly­ sip/ioi/el/a, as well as the genera oligoplagia and h%­ coc/ia. herak also drew palaeoecological conclusions regarding the isolation of their habitat. he was only able to attr ibute stratigraphic value to two species: c%spol/gia dllbia (upper ladinian) and amblysipho­ licl/a rimorica (midd le triassic). one of the most significant "nonalgal" papers of professor herak deals with the palaeontology of the eave bear (urs/ls spe/aclis) and although published in 1947, remains undoubtrully valid. it is obvious that this work has been stimulated by the rich museum collec ­ tion consisting or cranial vertebrae, long bones and teeth. this abundant osteological material was collected at various sites in croatia (medved a cave ncar lokve, vindija, bednik ncar petrinja, bobota, vrapce, cero­ vacke caves and others). in his st udy herak (1947) used biometric analysis and described morphological features of teeth, comparing his results with variational curve of the total range of the speeies (ehrenburg, 1935). this work represents a significant con tribution to the previous understanding of the most frequent pleistocene animal remains in the dinaric and eireum ­ dinaric karst region. i institute of geology, sachsova 2, p.o. box 26g, i-ir-ioooo zagreb, croatia. :'. depanment of geology and palaeontology, faculty of science, university of zagreb, uj. kralja zvonimira 8, hr-toooo zagreb, croiltiil. 3 dcpartmcll1 of gcology and palaeontology, croatian museum of natural i listory, demetrova i, hr-i (x)()o zagreb, croatia. the greatest number of herak's palaeontological works are related to the research of calcareous algae [rom late palaeozoic and particularly from the triassic . this research has continued with variable intensity for over twenty years and resulted in herak's numerous publications. after a relatively long "silent period" of research on the calcareous algae of shallow-water carbonates during world war ii and afterwards, herak started a new chap­ ter in the research of the calcareous algae, particularly the dasycladaceac, herak investigated various deposits from croatia as wcll as from the former yugoslavia, and thus he was among the first ones, together with kochansky-devid6, who initiated a new period of rese­ arch on fossil algae in europe. 'they were later accom ­ panied by a number of authors from zagreb where this kind of research has been traditional fo r more than a century. ijow is herak's interest in the calcareous algae explained? was it caused by the earlier discovery of, and research on the upper palaeozoic and adjacent tri­ assic in ml. velebit, done in the salopek's team, or her­ ak's personal contact with pia's works and algal mate­ rial during his stay in vienna? was it because our scien ­ tists arc predisposed towards the triassic deposits or because of the idea that advancement in exploration or the triassic is possible by detailed study of the calcare­ ous algae, especially the dasycladaceae? the last ques­ tion reflects on the whole algae research of herak which can be observed from two points of view: 1) taxonomic cont ributions and palaeontological consideration of sep­ arate genera and species and 2) the st ratigraphic, i.e. biostratigraphic aspects. this is related to the vertical range of a specific taxon, or the complete algal associa­ tion as well as their sig nificance in the stratigraphic attribution of certain sedimen ts or the recognition of contemporariolls facies. in his first paper concerning the calcareous algae he wrote about their stratigraphic and palaeontological s ig­ nificancc and stated some morphological characteristics (herak, 1950). he also surveyed particular clements this paper was presented at the scientific meeting dedicated to the 80th anniversary of the life of professor milan herak, held on march 5th, 1997 in zagreb 144 of their phy logeny and pointed out the recapitulation of some ontogenetic stages which are probably analogous to phylogenetic stages. herak viewed at the fossil find s on the basis of their distribution, and characteri stics of the recent dasycl adacea n e nvironm ent which can be taken as facies and climatic indicators, showing their lithogenetic importance in the development of the car­ bonate deposits. he hi gh li gh ted the elements of algal structure which shou ld be observed, and explained the ir importance for reliab le determination, bearing in mind which characteristics arc essential and which diles could be the consequence of adaptat ion. herak indicted the relationship between the scientific diagnosis of the species and the number of researched i.e. observed samples, a nd lhe state of the original material which was used for primary descr iption and reconstruc tion. thus almost all the basic questions concerning calcare­ ous algal research have bcen asked and they remain rel­ evant today, so that herak's work functions as the noti ­ fication of the wo rking hypothesis which wi ll be rea­ lised in subsequent works. in this context herak consi­ ders the genus dip/opora in the association of triass ic algae, w hi ch con tain s forms with a me taspondillous pattern of branches, while the other characteristics vary from spcc ics to spccics (herak, 1950). herak trea ted the genus dip/opora ancl the relationship between lheir particular species several times, adding new observa­ tions and understanding of the ir stratigraphic position and signi fi cance (herak, 1950,1956, 1957b, 1960, 1965). in these publications the distinction of the spe­ cies dip/opora allllll/arissima and d. ({i1i1l//ala with dif­ ferentiated taxonom ic cr iteria was rea lised . frequent discover ies of the species d. allllulatissima havc been made at numerous sites in croatia, particularly in lika, in an associati on which is characteristic for the ladin­ ian (d. allllil/ata, tcutlopore/ /a herc[{/ea etc.). herak expanded the time span for this spec ies to the ladinian, thus extendi ng the distribution of that species from a previous known an isian age, documented in the east­ ern and southern alps. outside c roatia herak' s achi­ cvemcnt was later l1sed in various stratigraphic intcrpre­ tations of the transit ional zone between the " mendola" dolom ite to buchenstein deposits in the range of the sari dolomite in the southern alps, as well as the time span for anisian and ladinian equival ents in the sile­ sian triassic. also, it was emphasized tha t part of the welterstein depos its belong to the upper ladinian , cor­ responding to several sites in mt. velcbit. in a more extens ive analysis herak (l957b) di s­ cussed the problem of the species d. annulata which, according to pi a included three varieties (dolomitica, septel/friojlalis and debilis) and two form s of trichofora and vesicu lifera which he considered to be the result of sexual dimorphism. refuting all three varieties founded on unproved hypothes is as well as the sex ual dimor­ phism, herak relied on firm morphological distinctions of the species, and offered a new di vision of the species d. al/i/ulata into two subspecies . in one su bspecies he included speci mens with vesiculiferous branches and vcologta lfo;1i1ca ;1\j/1. according to the priority principle he nominated it as d. allnu/ata subsp. dolomitica pia and the second sub­ species included specimens with trichoform branches as a type species nominated as d. af/illtlata subsp . al/llltla­ ta herak. i-ie es tablished the time span for bo th sub­ species up to the upper ladinian and this has been later well documented at numerous sites in the dinarides. herak (1965) ex tended his work on a detailed survey of the sites and morphological characteristics of severa l genera : telttloporel/a, macropore//a, gyro­ porella, oligopore//a , physopore//a and dip/opol'a and this enabled the el uc idation of the ir basic morphologi­ cal features and allowed determination of the relative stratigraphic positions as well as associations where the above taxa have been discovered. as in the case of d. awl/tiata herak prefered intraspecific category transfer­ ring the species d. hexaster and d. he{vetica, into the subspecies d. hexastcr subsp. hexasler and d. hex((sfer subsp. helvetica on the basis of poorly developed sha­ pes at the end s of the branches. besides his first determinations of various genera in the dinarides and their stratigraph ic distribution, herak was also concerned about phylogenetic relationshi ps as well as s ignificance of morphological characterist ics in taxonomy. herak was well aware of many difficulties in phylogenet ic reconstructions within various taxa, and thus he exploited the significance of morphological fea­ tu res in taxonomy. herak is critical of the usage or small and gradual morphological differences in the delineation of taxa and he is of the opinion that estab­ lishment of subspecific variation is m ore appropriate than the foundation of new taxa, as such units could be more easily revised and defined. with the introduction of such a theore tical approach herak emphasized the neccssity of application of the taxonomic criter ia and his theoretical frameworks are st ill val id. herak considered calcareous algae and thei r impor­ tance in the st rati g raphy or the late palaeozoic and mesozoic of the dinaridcs in several papers (h er ak, 1960, 1966). along with listing silcs in dinarides where aji previously cstablished species of gymnoeodi­ acean, cod iaeean and dasycladaeean al gae have been discovered, and their stratigraphic position, he added new data with es tablished changes to stratigraphic dis­ tribution. for several spec ies, he extended thei r strat i­ graphic range, considered the range previously known (e.g. permocalculus fene//us has been extended to early permian, etc.), and he also commented upon the taxon­ omy of the genera anthracoporella, vermiporcl /a, per­ mocalculus, epimastojjora , etc . for severa l species of the genus perrnocalcu!us (p . fragi/is, p. mollo/i/ol'lliis and p. sofidus) herak considered unifying them unde r the ilame p.fragilis. in his overviews, presented also at international meetings, herak has integrated the results prev iously achieved by several authors, which enabled the european algal society to become acquainted with croatian ranges and our contribution to the research of the fossil calcareous algae at the critical time. sok:10, bajraklan;vic & jlli-i.~ic l'olibk: ac:ldcmician milan herak 's main contriblilion to palaeontology 145 as a competent and established expert in calcareous algae, herak has worked on the taxonomic and strat i­ graphic intcrprctation of samples from slovenia, aus­ tria and greece, incorporating his results into the inter­ pretation of regional gcological scttings as a base for speculations over the tectonic and hydrogeologic set­ tings, he has described sevcral species, subspecies and variations or dasycladacean algae, especially the trias­ sic ones, these include physopore/la mil/ut%idea herak 1967; ph. likallo herak 1965; p/i. croalial herak 1958; diplofjora su/jrilis pia val'. gracca he­ rak 1967; d. 0111111/010 subsp. annillara (pta 1920) herak 1957; d. annll/ala subsp. d%milica herak 195 7 and cayellxia medilerranea herak 1967 from the cyanophycean group. as previollsly mentioned, most of herak's papers havc bcen dirccted toward stratigraphic dctermination, defining the distribution and mutual re lationship bet­ ween previously poorly defined complexes of deposi ts and their facies in the late palaeozoic, and particularly the triassic. this understandi ng of fossil calcareous algae has enabled for the first time the definite div ision of the middle triassic of the part of lika below the velebit ml; the establishment of the anisian and lacii­ nian at numerous localities in the outer dinarides; the development of clastic facies of both the middle trias­ sic stages, as well as defi ning the entire range of certain taxa and whole algal communities. also, all of these papers, even smaller volumes, contain some palaeonto­ logic and taxonomic novelties. reports of the finds of some species, including isolated species, in the area of the dalmatinska zagora, lika, kordun, hrvatsko zago­ rje and the mountain s of slavonia, arc also valu able because these finds stimulated later researchers to col­ lect this precious material, enabling more comprehen­ sive elaboration or calcareous algae with in the entire mesozoic and even pan of the palaeogene. the "algae" sphacrocodilll1l borncl1iallni roth pletz (sec her­ ak, 1952, 1957a) remains a valid indkator of shaliow­ sea sedimentation in the upper triassic due to its mor­ phology, defini tion of original palaeoenvironment, method of decay and visual characteristics. significant papers from the algal opus of herak are also the result of collaboration. in co-authorship with the late professor y. koehansky-devide (herak & koci-iansky-deyide, 1960; kochansky-dey­ ide & herak, 1960) the calcareous algae of the late palaeozoic of velebit mi., as well as samples from the sites in gorski kotar , slovenia, serbia and montenegro, were described. new taxonomic contributions were provided by description of the new genus and species c/avaporci/a ca/icilorl1lis and several new species of previou sly known genera includ ing anlhracoporei/a i'ieilla, mizzia corllllla, epimasropora likana, e. a/pina and dljj/opora plfsi/la. the morphogenetic comparison for the spec ies anrhracopore//a specrahilis pia and newly-described ai/lhracoporc/la vicina was shown . the comparative analysis of several species of the genus vcr/mj)orcl/a was carried out, suggesting that v. ve/ebit(liia is probably younger synonym of the species gyi1l17ocodilll1l bellerophonfis. the descr iption of the species vcrmiporclla serbiccl pia was expanded, and the genus epimasropora, despite unclear morphogenet­ ic characteristics, was extended with two previously mentioned species (e. likalla and e. alpilla). the uncer­ tainty of the genus hicorocodiul1i (h. elcganrc endo), the organization of which is atypical of dasycladacean algae, was highlighted. the paper by herak et al. ( 1977) entitled "the development of the dasyclad algae through the ages" is among the significant contributions in calcareous algae palaeontology, due to its eva/ualion and observa­ tion of morphogenetic features of algal evolution along with consideration of the phylogeny. based upon the 29 morphological features, accompanied by their age, the correlation of 80 suitable gcnera was carried out. the authors proved that the continuity level of a ccnain fea ­ ture corresponds with its regularity, and is opposite to the level of differentiation and specialisation, the atti­ tude that the increase in differentiation is the result of evol uti onary changes, and that fossil dasyc\adaceans could be gathered into several morphogenetic evolu­ tionary levels, with their rcpresentativcs dispersed in lime, has been expressed. based upon these features, five groups havc been formed, which include some common characteristics. the sequence of the separated groups through the geological past, also shows the evo­ lution from the first group with the most primitive fea­ lures to the fifth group, the youngest, with differentiat­ ed and specialised feature s . thc application of thesc features enabled not only the classification of the main genera of fossil dasyclad algae, but also the infilling of some gaps, by checking the type material of some doubtful genera. this paper has remained valid as an analysis of morphogenetic characteristics, their deve­ lopment, differentiation and specialisation in the phylo­ genetic succession, on the occasion of this anniversary, when we cele­ brate and acknowledge the long-standing, rich opus that academician herak leaves us , we cannot emphasize enough his contributions to palaeontology and geology, especially in the field of calcareous algal research. numerous citations of herak's papers in croatian and, even more often, foreign publications, as well as the na­ ming of several taxa after herak by some authors, could serve to emphasise the acknowled gement and value of herak's papers. these taxa are: physopo/'c//a hcraki var. hcraki bystricky 1967; ph. hcraki var. icill.lipo1'0 bystricky 1967; cymopolia ireraki gusic 1967, later denoted as a younger synonym of c, fiiayaclise johnson & kaska 1965, after deloffre & radotctc (1978); pe/raseu/a ?lreraki sokac & ntkler 1969; /-ierakel/a paradoxa kochansky­ dey ide 1970; hexae//a ireraki milanoylc 1989 and aslcroca/ell/lls heraki sokac & grgasovtc 1998. working on the fossil a lgae from several european localities and publishing his papers in several foreign 146 jourpals and occasional publications, professor herak has offered the european and global palaeontological community an insight into the croatian approach and achieved results in the palaeontological and stratigra­ phic investigations of the fossil calcareous algae. with his comprehensive, but also differentiated approach to the series of open questions in the field of taxonomic, phylogenetic and stratigraphic domain of fossil calcare­ otis algae, herak has initiated and guided (together with professor vanda kochansky-dev idc) the path whieh remains in the papers of later researchers, and which is today in the european algal community frequently cal!cd "the zagreb algal school", his devotion to palaeontology is revealed in the preparation and publication of the textbook "palaeob­ otany" (herak, 1953, 1963). besides its assignment to the sllldents of geology and biology, the aim of this textbook was to introduce a wider society of readers to palaeobotanical issues, and to get them acquainted with the most typical plants from the geological past ancl their inlluence in geological processes. he also published many popular articles in "priro­ cia", in the edit ion "znanje i raclost", in "zadruzni kalcndar" etc., acquainting everyone with the basic ide­ as ancl meanings of palaeontology, palaeobiology and geology in general. references bystricky, j. (1967): die obertriadischen dasy­ cladazeen der westkarpaten.geologicky sbornik­ geologica carpathica, xvjii/2, 285-309, bratislava. deloffre, r. & radoicic, r. (1978): algues cal­ caires (dasycladales) du paieocene de slovonie (yougoslavie).bull. des cent. de rech. expl.­ prod. elf-aquitaine, 2/1 , 61-95. ehrenburg, k. (1935): die pleistozanen baren bel­ glens: 1. die baren von hastiere.mem. mus. roy. d'i-list. nat. belg., 64, brtissel. g u~;]c , i. (1967): new dasycladaceae from the maestrichtian of bcspelj near jajce (western bosnia) (nove dasikladaceje iz mastrihta bespclja kod jajea).geol. vjesnik, 20,117-126. herak, m. (1943): sec # i in bibliography of profes­ sor milan herak (this vol., p.127-135). herak, m. (1944): see # 5 in bibliography of profes­ sor milan herak (this vol., p.127-135). herak, m. (1947): see # 9 in bibliography of profes­ sor milan herak (this vol., p.127-135). herak, m. (1950): see # ii in bibliography of pro­ lessor milan herak (th is vol., p.127-135). herak , m. (1952): sec # 14 in bibliography of pro­ fessor milan herak (this vol., p.127-135). lieologl:l croane:! :"lull herak, m. (1953): see # 16 in bibliography of pro­ lessor milan herak (this vol., p.127-135). herak, m. (1956): see # 25 in bibliography of pro­ !'essor milan herak (this vol., p.127-135). herak, m. (1957a): see # 31 in bibliography of pro­ lessor milan herak (this vol., p.127-135). herak, m. (l957b): see # 32 in bibliography of pro­ fessor milan herak (this vol., p.127-135). herak, m. (1958): see # 33 in bibliography of pro­ fessor milan herak (this vol., p.127 135). herak, m. (1960): see # 40 in bibliography of pro­ fessor milan herak (this vol., p.127-!35). herak, m. (1963): sec # 55 in bibliography of pro­ fessor milan herak (this vol., p.i27-135). herak, m. (1965): sec # 63 in bibliography of pro­ fessor milan herak (this vol., p.127-135). herak, m. (1966): sec # 67 in bibliography of pro­ fessor milan herak (this vol., p.127-135). herak, m. (1967): see # 73 in bibliography of pro­ fessor milan herak (this vol., p.i27-135). herak, m. & kochansky-devide, v. (1960): see # 43 in bibliography of profcssor milan herak (this vol., p.127-135). herak, m., kochansky-devide, v. & gus1c, i. (1977): see # 144 in bibliography of professor milan herak (this vol., p.127135). johnson, j.e. & kaska, h.v. (1965): fossil algae from guatemala.professional contributions of the colorado school of mines, 4, 152 p., goldcn. kochansky-devide, v. (1970): die kalkalgen des karbons vom velebit-gebirge (moskovicn lind kasimovien) (vapnenacke ajge karbona velebita (moskovijen i kasimovijen)).palaeontologia jugo­ slaviea, 10, 32 p., zagreb. koci-iansky-devide, v. & herak , m. (1960): see # 44 in bibliography of professor milan herak (this vol., p.127-135). milanovic, m. (1989): [-iexaella heraki n. gen., n. sp. , a new problematical (incertae sedis) microfossil from the lowe r permian of gorsb kotar region (croatia, yugoslavia).geol. vjesnik, 42, 29-3 1. sokac, b. & grgasov1c, t. (1998): astcrocalell­ ius heraki n. gen., n. sp., a new calcareolls alga (gy­ mnocodiaceae) from the upper triass ic haupl­ dolomite of zumberak, north croatia.facies, 38, in press, erlangen. sokac, b. & nikler, l. (1969): 0 vrstama roda petrascula iz donjeg lijasa vclebita (on the species of the genus petrascula from the lower liassic of velebit).acta gcol., 6, (prir. istrqz_ jugosl. akad. znan. limjtt., 36), !o3-112, zagreb. geol. croat. i 49/2 277 . 281 1 fig. zagreb 1996 i ncl'iew paper hydrocarbon reserves estimation, classification and importance in evaluation of exploration projects zvonimir nadjakovic, josip secen and antun bauk proceedings key words: hydrocarbon reserves, classification of reserves, evaluation of exploration projects. abstract one of the key problems encoun tered by oil companies from couiltries in transition approaching the world market is in understand­ ing the collcept of reserves, their estimation lind classification. as reserves afc the basic valuc of a company , il is imperative that busi ­ ne ss policy includes continuous replacement of reserves. the study illustrates the usc of esti mated reserves in the evalu ation of ex plo­ rat ion areas, and lhe imporlance of reserves in business decision s and a company' s fulure. 1. introduction the concept of market economy necessarily requires the valuation of each asset held by a company. for compan ies registered in some of the stock markets, i.e. public co mpani es, reporting the annual economic state is mandatory. the value of an oil company lies in the value or its oil and gas reserves. tn order to make the reserves of various companies mutually compara­ ble, a more or less similar classification system has been accepted in thc world of market economy. the basic characteristic of the system is that only those quantities of hydrocarbons that can be profitably recov­ ered using existing tech nology arc estimated as reserves. in reserves estimation the real production behaviour is emphasised, i.e. production decline curves or mathematical modelling arc used, as well as practical experience gained from similar field s. when gas fields are in question, the material balance method has been accepted as reliable. the consequence of such an approach is a conservative estimate of reserves that results in frequent upward revisions. in the fonner socia list block countries, including the form er yugoslavia, a system was adopted which aimed at determination of theoretically recoverable quantities of hydrocarbons. such an approach has resulted in more optim istic es timates, and with some exceptions it is still used in practice today. moreover, they developed a classification system for mineral energy resources only, and nol rcservcs. though il gives a good insight into thc lna -naftaplin, subiceva 29 . hrl 0000 zagreb, croa lia. kljucne rijeci: zalihe ugljikovodika, klasifikacija zali­ ha, vrednovanje istrazivackih projekata. saictak jed'l n od kljucnih problema naflnih kompanija iz zemalja 1i tranziciji pri prislupanju svjelskom lrzislu jesl razumijevanje pojma zaliha, njihovog procjenjivanja i razvrstavallja. za lihe su lemeljna vrijednosl nafln e kompanije. irnperativ poslovne pol it ik e je slalno obnavljanjc zaliha. prikazano je kako se procijenjene zalihe korisle za vrednovanje istrazivackih lokalitela, odnosno koliki znacaj im,~ill pri donosenju poslovnih odluka, pa i za buducnosl same kompallije. mineral resource potential of a certain country, it cannot be used ei ther in conducting the business policy of a company at an operational levcl or in the real estimalion of its financial position. when approaching the world market, each company should present its annual financial report. as hydrocar­ bon reserves represent the most important part of oil company assets, their classification and estimation should conform with international stratcgy rules. as the term "markel" implicitly includes every market, e .g . money market, hydrocarbon reserves market or explo­ ration areas market , the internationally acceptable reserves classification and estimation system becomes a neccssity. it must bc mentioncd here that in the evalua­ tion of a certain exploration prospect or one exploration well , the start point is ei ther undiscovered potential reserves or future in itial rescrvcs, which arc cstimated in a similar way as for proven reserves. 2. the concept of reserves, iloth in croatia and internationally the croalian "by-law on data gathcring, thc manner of recording and es tablishing reserves of mineral resources as well as the preparation of balancc shcet for these reservcs" clearly dcfines what is mcant by reservcs. it is obvious that it refers to the volume of mineral resources found in a reservoir. dcpending on the degree of ccrtainty, these quantities are classified inlo the a, b, c i , c2, d i and d 2 catcgories but by the deterministic approach. not all the quantities of mineral rcsources in a reservoir can be produced, and only some 27~ can be profitably produced. it seems, the refo re, that the te rm "reserves" is inadeq uate. however, in order to repon vol umcs that can be profitably produccd the a, b and c 1 categories are classified i l110 economicall y and uneconomica lly recoverable reserves. the economical­ ly recoverable reserves are oil and gas volumes that can be profitab ly recovered, and they, in fact, represent the reserves. as the by-law docs not defi ne the method 1'01' es ti­ mating the profitability of rese rves, a static method is most frequen tl y used for these estimates, in contrasttq the rules applied in market economies that require cash flo w ca lculati on, i.e. d iscounted cash fl ow anal ys is . besidcs, the degree of cerlainty of so de te rmi ned reserves, is not unique. in the majority of countr ies with market economics, minera l resources a re divided in to di scovered and undiscovered, and those discovered arc furt her d ivided into reserves (initial) and un recoverable quantit ies. \ve shall focus ou r attention on the reserves. a cl ass ifi ca­ tion o f reserves is presented on fig. l. the remai ning reserves arc class ified according to th e degree of certainty which indicates the techni ca l and eco nomic probability of recoveri ng the c lassified volumes or reserves. 1n the determin ist ic approach to reserve es timation, the degree of certainty is reported descr ipti ve ly. the evaluator, according to his profes­ siona l judgement, classifies the reserves in compliance wit h the c riteria accept ed by the socic ty of pet roleum engineers (e.g. society of petroleum evalu­ at ion engineers , 1988, and t he petroleum society or: t i-ie canadian institute of mi­ n ing, metallurgy and petroleum , 1994). some <w thors consider the certa inty of proven rese rves 10 be almosl 100%, probable 50% and possible 10%. in the probability approach to reserve es timates, the degree of certaint y will be assigned nullle rica l values <i nd, depending on the country and company, proven reserves would be th ose dete rmi ned with a re liability grea ter than 80% or 90%, probable from 40% or 50% to 80% or 90% and possible from 10% to 40% or 50 % (cald well el al. 1993). gcologb croatie:! '19[2 fig. i a c las~ i ficalio ll of reserves. t he basic charac tc risti c of pro ve n developed reserves is thai they are those quantiti es of hyd roca r­ bons tha t can be recovered from ex isting wells and sup­ p lied to the market by existi ng gat hering and tran s­ portation systems. undeve loped reserves a rc the reserves the prod uction o f which req uires significant inves tment, but projects or studi es con firmin g thei r eco­ nom ic .iustifi ca ti on are already available. in co ntrast to this, the recoverable reserves in croatia, in addi tion to a d ilterent level of technica l reliability, a re o nly roughly es timated. conce rni ng old fie lds wit h co mple ted pro­ jec ts and proven profitability, those reserves arc close or identi cal with proven reserves. in new fie lds, for which the project or study has yet to be prepared, the reserves might bc categorised as p robable or possible, dependi ng on the degree o r certain ty. in other wo rds, addit iona l well s shou ld somctimes be dr illed and com­ ple ted in these new fi elds and a ll the necessary infra­ struc ture, as well as the gathe rin g and transportation sys tem, construc ted. all thi s requires large investment that has to be justified in order to c lass ify hydrocarbon quantities 10 be recovered frolll these fields into proven, but undeve loped rese rves. t here fore, th e reserves of non-producing fi e lds categori sed acco rdi ng to the by­ law as recoverable reserves, shou ld be cons idered prob­ able or possible, depending 011 the degree of certainty. lei us emphasise once more the di/terence in cate­ gori sing the hydrocarbon reserves in marke t or iented and social ist economies. in marke t economics the term reserves applies lo those volumes that can actually be supplied to the market. it means that a ll the real prob­ lems of production arc taken in to consideration, from a damaged ncar well bore zo ne, throug h the imperfec­ tions of fl uid lifling and transpo rt clli on sys tems to ihe untimely and somet imes ine ffecti veness of workover operations. all these arc theorctically unpred ic tab le. thi s is why, for reserve est imatcs, a real fi e ld perfor­ mance is used or so call ed " producti on decl ine curve" or analogy wit h a similar fi e ld. contrary to this, in for­ mer socialist countries emphasis was placed on theoret­ ically recoverable vo lumes at reservoir level. tl means that in predicting the future behaviour very sophis ticatnadj; lk ov ic, secell & l3:wk: i !yclrocarboll rcscryc~ · i~slimalioll, clnssirication and !mportance ... 279 cd calculations are sometimes used, to calcu late theo­ retically recoverable volumes, but they cannot reflect <:ii[ the complexities of real production. 3. economic evaluation 1n this study, discussion of economic evalu<:ition is separated although in the m<:lrket economy it is an inseparable part of the eslim<:llion or both the degree of certainty and quantity of" reserves. this is due to the fact th<:lt only lhe quantities that can be profitably produced and supplied to the market under definite technical and economic conditions are considcred as reserves. the by-law or the reserves classific<:ltion issued by the republic of croatia requests only a rough economic evaluation. such evaluation cannot be used either as a basis of investment or for estimating the profitably recoverable quantities of hydrocarbons, i.e. reserves. the economic evaluation in the market economy is based upon criteria accepted by the stock exchange commission, and the same criteria arc incorporated into fnt ern<:l tional accounting standards. the economic val­ ue is determined by applying the method of cash flow calculation at constant prices and costs at the end of the previous year and a 10% discount rate (financial accounting standards board. 1982). the result of such an approach arc various indices of the project erfieieney and reserves esti mation. among the indices arc payout time, return on investment , rate of return and net present value. with a correct prediction of future ficld performance and all futurc costs, one can obtain an evaluation which is a good basis for making business decisions. there is no need to describe in detail the ca lculation methods, as they arc already well known. when making the economic evaluation it is very important to properly determine the investment risks. in the process of es tablishing the risk, the evalua­ tion or geological and technical uncertainty is , in princi­ ple, less prob lematic than that of political and economic uncertainty, but they have to be evaluated too, as they can substantially affect the final result. 4. evaluation of exploration areas and wells every enterprise, regardless of type and size must , ror the sake or survival and development, continuously eval uate business efficiency. for oil companies there is an additional impera tive, i.e. the replacement of pro­ duced quantities or hydrocarbons by newly discovered reserves. both requirements have to be compatible regardless of the exploration and production conditions. the basic principle or success ful business is that income must exceed expenditure. the success of any bus iness can be expressed by the simple equation: pro"it ~ volume x (price variabl e / unit costs) fixed costs taxes the volume of hydrocarbons is dilticult to quant i­ fy. ]1 is est imated by means or various methods at d if­ fe rent stages of exploration or development. the accu­ racy of estimation increases with the number and relia­ bi li ty of the available data on the reservoir geological model, fluid and rock properties as well as the recov­ ered fluid volumes. the price of hydrocarbons is beyond company con­ trol and prediction of fu ture prices represents a large unknown when defining basic long term objectives. costs, including overheads, can and must be con­ trolled by the business policy of the company and ind i­ viduals. taxes are also beyond the control of a company as they are controlled by the state depend ing on ils inter­ ests and needs. accordingly, this cquation indicates that making profit involves several unfavourable factors and may be controlled mainly by costs. geologists and petroleum engineers can contribute to this business in two ways: increasing and maintaining volumes; reducing or controlling costs per unit volumc pro­ duced. while the other indices from this equa tion depend on the economic, political and social conditions of a certain country, the explorationist should also take into account and direct the activities toward conditions which are jllore favourable for the company. these are general principles of profitable hydrocarbon reserves exploration, and lheir clements will be discussed latcr in more details. the procedure for estimating the value of any given exp loration area commences with determination of the undiscovered potential reserves value. this is deter­ mined by calculating the cash flow. costs of failure should a lso be estimated, e.g. those of a dry well. or particular importance is determination of the probabili­ ty of a success. by these means a predicted cash value is calcu lated, which may be simply represented as: emv ~ [vr x ps] [cf x (i-ps)] where vr is value of rese rves , ps probability of suc­ cess, cr costs of failure and emv expected money value. an ex ploration well can be evaluated in a sim ilar way. there is also the possibility for comparing the exploration well results in a ratio obtained by dividing the expected cash now value by th e dry well cost. another index, which can be llscd in project ranking, is obtained by dividing the expected cash flow value by current investment value. this index gives an expected income per unit of investment. the approach, method­ ologically identical to this , applied in the proven reserves estimate, facilitates the evaluat ion of the exploration projects. this evaluation is to be made not only at the very start of the process, but also during 2xo each phase when changes occur due 10 either new tech­ nical perceptions or new econom ic conditions. 111 this manner condilions will be created which would make it possible 10 conduct the exploration operations in an extremely profitable way, and 10 achieve ihe optimum results by invcsting into hydrocarbon exp loration. various methods and rules arc used in the determi­ nation of the effects of inves tment s, which are applied by oil companies when making decisions on investing into exploration projects. some of the si mple criteria frequently used in world practice in exploration area evaluation (jones, 1992) may be considered: 1. if the llndiscollnted gross value of total produc­ tion from the hydrocarbon accumula tion docs nol exceed al least 40 times the discovery costs (land pur­ chasing and drilling costs) the project is not cost effec­ tive and should bc abandoned. thcre is a suggestion [or the rotio to be evcn 50: i (ha rdin , 1958). 2. a project must not be started in any case when the rate of return is not greater than certain values cstablished in advance: • for a high risk area • for a medium risk area • for a low risk area 30-40% 20-30% 15-25% unfortunalely praclica l experience ind icates the fact that cxplorationists have a poor perception of ri sk, i.e. low-risk projects fail more orten than expected. in spite or this imperfection, some eva luat ors of explora ti o n areas find this approach very viable. 3. if the project will not payout in less than "x" years, it should not be started. • individual wells in 2-2.5 years • new field in 4-5 years, depending on size this rulc is particularly applicable to smaller fields ncar large ones, where pipelines and othcr facilities alrcady exist. howcver, discounted payout may be a more realistic measure. 4. the average discovery costs (includi ng devclop­ ment) in 1989 in the usa were approximately: ·31.5 usdjlll] (5 usd/bbl) for oil, ·27 usd/iooo m] (0.75 usd imc!) (or gas . similar figure s are given in herold's annual reserve replacement cost analysis for world wide opef<!tions , 1993. hi gher costs make the project unprof­ itable. costs of discovery include all dry hole costs, and should be divided by the probabili ty of success to adjust the risk and allow valid comparison with other projects. 5. any gas explorati on and production project should not be started if it will not return at least 35 usdjlooo m] (i mil. usd/billion cuft ) . this also inc ludes development drilling costs. 6. the ['irsl well should "earn" enough to pay for land, seismic surveys and drilling. 7. no new field wildcat vel1lure should bc taken if, after [he wildcat which proves to be successful, drilling geologia croaliea 49/2 of at least three offset development wells is not feasi­ ble. this represents "some rules of thumb" used mostly in the usa in evaluating exploration areas. a realist ic approach to the valuation of exploration prospects, for the croatian oil company , becomcs a necessity under conditions of fairly stable prices and in a highly explored operational area. evaluation of the exploration area as much obj ectively as possible becomes imperative under conditions of comparative ly stab le prices of hydrocarbons in an area prev iou sly highly explored. today one cannot rely on ci t her a sig­ nificant price increase or large discoveries. por these reasons it is necessary to evaluate the exploration pro­ jects as rationally as possible. in the foreseeable future hydrocarbons remain the inevitable energy resource and mineral reserve to be used in the chem ical indu stry. this means that th e process of exploring, discovering and putting into pro­ duction new reserves is continuous, but under consider­ ably more difficult technical and economi c condi tions, as is constantly reite rated by the leading people of big oil compan ies . thi s could a lso be applied to ihe oil companies in the former soc iali s t countries, in the maj ority of which exploration operation s were rather extensive, and during transition into the market econo ­ my the rationalisation of the explo rat ion processes, as well as other act iviti es of oil companies was more strongly emphasised. 5. ina-naftaplin and the trend of the market economy analysis of the reserves management at ina-nafta­ plin encounters al l the problems indicated in th is study. the remain ing oil reserves are contained in old fields with high production costs. when estimating ihe remaining rcserves according 10 standards common to western countries, it has become certain tha t production costs will considerably reduce the remaining economic production life of the fields. it is a lso certain that recov­ e rable (techn ical) reserves, due to a long productive life, wjjl generally meet the criteria introduced by the new evaluation approach. in order to increase the rcmaining reserves produc­ tion cos ts must be reduced, i.e. to make detailed analy­ ses of each item loading these costs. another method of improving th e cost effectiveness of each field is to increase the well productivity by introducing new tech­ nologies adequate to the rield conditions. the world price of oil products and an aspiration to enter the petroleum business world presumes thai all the costs of our activ ities arc brought as soon as possi­ ble to the world level. it requires not only the definition of the company from thc organisational point of view, but also it's streaml ining. in thi s process, the non st rateg ic, financ iall y mar­ ginal and other undesirable investmen ts should be cl imi\,utj:ll-ovic. scccn & baul-: ilydrocarbon l{c~erve.~ e~lilllalion. cta:.~ific;nion and imtlorl:mcc ... 281 in<llcd, with a pa ralle l rcstructuring and reorgan isa tion per formed whil e pl nn nin g the strategic growth of the company. 1n con trast to thi s there is an option for the company to downsize by reducing all acti vities by a certain per­ centage, withou t any c lear plan of growth . h the fi rs t opt ion is to be applied, i.e. the concept of g rowth, regula r rep lacement o f rese rves should be ach ieved through care ful planning of all ac tivities in accordance with the company potel11ial. the reserves can be res tored by con tinuing explo­ ration in the country and ab road, by acqui sition of reserves and il11roduci ng the add itiona l recovery meth­ ods aimed al inc reasing the recovery of the remaining reserves in old oi l fi elds. there is a high probability that the remaini ng poten­ tial of the pannon ian exp loration area in croatia can ensure discoveries and new reserves for replacement or only a fraction of currcnt production. exploration ope rations abroad must be the basis of long term reserves replacement. the results achieved so fa r a rc encouraging, but future activ ities shou ld involve al l the human resources in orde r to se lec t thc most prospective prospects. there is no poss ibilit y for the short tc rm st abilis a­ tion of reserves without purchasing already d iscovered rese rves or field s in production on the open marke t. it is a new act ivity for the company and many diffi culties arc ex pected , but if we wish to initiate a new cycle of compan y growth , it is mo rc impera tive than optional. all these activities assume co-operati on with foreign oi l companies as we ll as the application of the illost rcccnt technical achi evemen ts in all stages of the oil and gas ex ploration and production process. 6. conclus ion the hydrocarbon reserves of the republ ic of croat­ ia, de fin cd according to the by-law, a re not directly co mparabl e wit h the proven, probable and possib le, c lassi fi cation used internationally, due to a d ifferent nppronch to the es timation from the techni ca l and eco­ nomic point of view. t herefore, a new es timation and c lnssi fi cat ion scheme should be implemented in order to establi sh the rinanc ial position of an oil company in croati a according to internationa l s tandards. a new by­ law (at leas t int e rnal ) about classifica tion or reserves should be prepared , which would take into co nsidera­ tion internati onal standards, i.e. be based upon the mar­ ke t approach. the reserves es timated and c lass ified in this manner would be the bas is for approaching the world marke t. it docs not mean that mineral energy resources should not bc repo rted. on the cont ra ry, they shou ld be assigned to loca lit ies, i. e. concession blocks, and the potential reserves es timated accordin g to the adopt ed rul es but taking into consideration the ri sk. a continuo lls reva luation of potential rese rves should be perfo rmed during explora tion, as all changes in costs or prices o f hydrocarbons could affeel the ir req uired vol­ ume, and by thi s could di rect ly affec t the cont inuat ion of works or their terminati on in case or unprofit ab ility. ina naftaplin is faci ng the necessity o f the optimi ­ sation o f the explorati on an d th e rationali sa ti on of deve lopment on the basis of the described valuation of reserves . appl yi ng cri tc ria accepted wo rld w ide and me th ods o f va luation of prospects, more e ffi c ient exp loratio n at ho me and abroad should be ac hieved, which, together wi th the acqui s it ion of new reserves, should result in a hi ghe r reserves replacement ratio. a replacement ratio of 1 must be achived as soon as pos­ sible. 7. refer ences ca ldwell. r.h. , gr ace, ld. & i-leather , d.1. ( 1993): comparative reserves definition s : usa, europe, and the former sov iet uilion. journ a l of petroleum technology, 45/9. 866-872. fi nancial accounting standards board ( 1982): statement or fi nanc ia l accounting s tanda rds no. 69. financial accounti ng standards board , stamford, connecticut , 1-49. hardin, g.c. ( 195 8) : economic factors in ihe geo­ log ical appraisal or wildcat prospects. gulf coast association of geolog ical societies transacti ons, 8, 14·19. jones. d.r. (1992): some bas ic bus iness concept s.· in: steinmetz. r. (cd. ): the business of petro le­ um exploration. aapg treatise of pet roleum geol­ ogy,7-12. society of petroleum ev aluatlon engi­ neers (1988 ): gui delin es for application of th e de finition s for oil and gas reserves.soc ie ty o f pe tro le lllll eval uati on eng ineers, mon og raph , i, liouston. texas, 1-69. the petroleum society of the canad ian institute of m in ing. metallurgy and petroleum (1994) : de termination of o il and gas rese rves .the pet roleum society of the canad ian instit ute of mining , metallurgy and pe trol eum , monograph, calgary, 362 p. 2x2 geologia croalica 49(2 geo.cro.2-3-61-kb.pdf 185 � baba senowbari-daryan1, ioan i. bucur2, felix schlagintweit3, emanoil săsăran2 and jacek matyszkiewicz4 ab stra ct several organisms or interaction of organisms have been described over a long time interval from the late palaeozoic to cretaceous as tubiphytes, with the type species being t. obscurus maslov, 1956. palaeozoic tubiphytes were revised by senowbari-daryan & flügel (1993). triassic representatives still need to be revised. for jurassic (extremely abundant in upper jurassic) and cretaceous organisms, known as “tubiphytes” morronensis crescenti, 1969, we propose here the genus name crescentiella. differences between crescentiella nov. gen. and tubiphytes maslov are discussed. the systematic position of crescentiella as a foraminifera, interaction of foraminifera and cyanophyceans or as a special kind of oncolite is discussed. it is interpreted as symbiosis or encrustation between cyanobacteria and a nubecularid foraminifera, uncertain tube or rarely, other biogenic components. comments on similar associations, e.g. the genus labes eliasova, are provided. keywor ds: crescentiella, tubiphytes, labes, cyanobacteria, foraminifera, systematics, jurassic, cretaceous. 1 geozentrum, university of erlangen-nürnberg, loewenich-str. 28, d-91054 erlangen, germany; (basendar@pal.uni-erlangen.de) 2 department of geology, babes-bolyai university, str. m. kogălniceanu nr.1, 400084 cluj-napoca, romania; (ibucur@bioge.ubbcluj.ro; esasaran@bioge.ubbcluj.ro) 3 department of applied geosciences and geophysics, university of leoben, peter-tunner-str. 5, a-8700 leoben, austria; (ef; schlagintweit@t-online.de) 4 faculty of geology, geophysics and environmental protection, agh university of science and technology, mickiewica 30, 30-059 krakow, poland; (jamat@geol.agh.edu.pl) crescentiella, a new name for “tubiphytes” morronensis crescenti, 1969: an enigmatic jurassic – cretaceous microfossil geologia croatica 61/2–3 185–214 8 figs. 8 pls. zagreb 2008 geologia croaticageologia croatica � 1. introduction rauser-chernoussova (1950) introduced the genus name shamovella for the fossil, later described by maslov (1956) as tubiphytes. according to elias (1959), ott (in kraus & ott, 1968), and croneis & toomey (1965), the name shamovella is a nomen imperfectum but riding (1993), pleads that tubiphytes is a junior synonym of the genus shamovella. later, the name shamovella was used by subsequent authors (e. g. le mone, 1995; riding & barkh am 1999; weidlich; 2001). vachard et al. (2001) introduced shamovella as a synonym of tubiphytes and mentioned that according to chuvashov et al., (see vachard et al. 2001) two forms of tubiphytes exist: “tubiphytes obscurus shamovella rauser chernoussova” and “tubiphytes obscurus obscurus maslov”. in this paper the popular name tubiphytes is still used. tubiphytes with the type species t. obscurus maslov (1956) was described from the permian of the ural mountains. two years later, the same organism was reported from the permian of the guadalupe mountains in texas and new mexico as nigriporella (with two species as n. magna and n. minima) by rigby (1958). tubiphytes and morphologically similar organisms are the most abundant problematic microfossils known over a long time interval from the carboniferous to the cretaceous in shallow water carbonates (riding & guo, 1992; senowbari-daryan & flügel, 1993). most geologia croatica geologia croatica 61/2–3 186 references are published from permian deposits, describing or illustrating the species tubiphytes obscurus maslov and the upper jurassic species of “tubiphytes” morronensis crescenti. an overview of the palaeozoic tubiphytes, including the type species t. obscurus maslov, and other species, as well as similar organisms, is given by senowbari-daryan & flügel (1993). all three “species” of tubiphytes (t. tubularis, t. polyvesica, t. spinalis), described by wu (1991) from the permian of xiangbo, china are considered younger synonyms of t. obscurus maslov. “tubiphytes” and similar morphotypes are abundant in the mesozoic, particularly in ladinian-carnian reefs of the tethyan realm. a revision of triassic “tubiphytes” is in preparation by senowbari-daryan. differences (see below) concerning the internal cavity and structure of the surrounding “cortex” between palaeozoic tubiphytes and the jurassic-cretaceous microfossil, known as “tubiphytes” morronensis crescenti justify the separation and establishment of an independent genus with the generic name crescentiella nov. gen. for the latter. crescentiella morronenis (crescenti, 1969) nov. comb. described originally from the jurassic of the central apennines (southern italy), is very abundant in upper jurassic epicontinental deposits of europe, (southern germany and time equivalent deposits in other countries including romania, poland, portugal), or in the alpine-tethyan realm of austria and other countries. it is extremely abundant in bavaria or in svabia (southern germany) in the upper jurassic (middle kimmerigian), “plattenkalk of treuchtlinger marmor”. “treuchtlinger marmor” is used as a popular building material for hall fl oors, windowsills, stairs etc., particularly in southern germany. crescentiella morronenis (crescenti) nov. comb. is also abundant in upper jurassic, open marine, tethyan shallow water limestones. all illustrated type material of crescenti (1969) represents individual specimens. in upper jurassic (tithonian) reefs of piano di battaglia in the madonie mountains, sicily, c. morronensis occurs not only as abundant individual specimens, but also as “colonial” forms building micro-constructions several cm in diameter. such “co lonial” forms are also abundant in upper jurassic reefs and platform carbonates in the shotori mountains, northeast iran, and are here described as crescentiella morronensis forma colligaris nov. forma. 2. material and methods the studied and illustrated material was investigated in polished slabs and numerous thin sections from different localities (see below), as well as in sem. material for sem-investigations was treated and etched for several hours with 3–5% “titriplex iii–solution”. the investigated materials come from the following countries: austria. thin-section material derives from the upper jurassic – early cretaceous (kimmeridgian – lower berriasian) plassen formation or plassen carbonate platform of the northern calcareous alps, mainly from occurrences in the austrian salzkammergut (e.g., gawlick et al. 2004, 2006; schlagintweit et al. 2005) and the resedimented barmstein limestones (gawlick et al. 2005, 2006). germany. the investigated material of the “treuchtlinger marmor” with crescentiella morronenis forma morronensis (crescenti) from germany comes from a quarry south of the village of treuchtlingen, near the mörenbach river. a detailed section of this region is given by kott (1989, fi g. 3) and a general overview of the occurrence of upper jurassic deposits is represented by meyer & schmidt-kahler (1984). the age of the investigated material is upper jurassic (kimmeridgian). iran. the illustrated material from iran was collected from the upper jurassic (oxfordian-kimmeridgian) esfandiar platform exposed in a hill, approximately 800 m south of the village of korond in the southern shotori mountains (fürsich et al., 2003a). italy (sicily). the sicilian material comes from the upper jurassic (tithonian), coral rich reef limestone exposed at pizzo carbonara in the madonie mountains, representing the marginal zone of the panormide carbonate platform (catalano et al., 1974; abate et al., 1988). the calcareous algae of this locality were investigated by senowbari-daryan et al. (1994), the foraminifera by bucur et al. (1996). poland. the upper jurassic sediments of the krakówwieluń upland (south poland), belong to the microbial megafacies, a belt stretching along the northern shelf of tethys (gwinner, 1971; matyszkiewicz, 1997a, 1999), including numerous microbial-sponge carbonate buildups and thick bedded limestones which are mostly microbial-sponge biostromes. the upper jurassic microbial megafacies developed mainly on the northern shelf of the tethys, and on shelves of the newly opened north atlantic. the investigated material comes from the upper jurassic bedded limestones of the liban quarry in kraków (southern part of the kraków–wielun upland). the bedded limestones are of upper oxfordian – (?)lower kimmeridgian age and developed as thick-bedded facies with cherts in which microbialites are the principal rockforming components (matyszkiewicz, 1989; krajewski, 2001). romania. in romania, crescentiella morronensis was found in upper jurassic limestones developed in the stramberk type facies from the following massifs: haghimas massif (dragastan, 1969, 1975) (east carpathians); piatra craiului massif (bucur, 1978), vânturariţa massif (uţă & bucur, 2003) (south carpathians); trascău mountains (săsăran et al., 2000, 2001) and bihor mountains (bucur & onac, 2000) (apuseni mountains). the age of all the localities is upper jurassic – lower cretaceous (oxfordian to early berriasian). 3. differences between tubiphytes maslov and crescentiella nov. nom. the type material of maslov (1956) from the permian of ural mountians and also specimens from palaeozoic of other localities in the world are characterized by the following criteria: geologia croaticababa senowbari-daryan et al.: crescentiella, a new name for “tubiphytes” morronensis crescenti, 1969... 187 a) the palaeozoic species tubiphytes obscurus and also t. carinthiacus (flügel, 1966) are composed of spherical, subspherical or mostly tongue-like segments, usually arranged one above the other, but also irregularly. each segment contains a separate internal cavity that can be a chambered foraminifera or a cylindrical tube, pear-shaped, globular or even an irregular object which can be placed in the middle, lower, upper, or at the peripheral part of the segment (see maslov, 1956, pl. 25, fi gs. 1, 3; pl. 26, pl. 27, fi gs. 1–2; rigby, 1958; riding & guo, 1992; senowbari-daryan & flügel, 1993; vennin et al., 1997). tubes or chambered fora minifera may pass through several segments. the younger segments may overgrow the older segments, so that the former are not visible from the outside. in contrast to specimens of tubiphytes obscurus, the specimens of crescentiella morronensis (crescenti) nov. comb. are tapered and cylindrical. the different growth stages in c. morronensis may appear as segments, but certainly segmented specimens, like tubiphytes, do not occur. segmentation or branching is falsely suggested by overgrowth of several specimens as shown from computer-based reconstructions in connection with serial sectioning (schmid & henssel, 2001; henssel et al., 2002). b) the surrounding “envelope” or “cortex” of palaeozoic tubiphytes composed of a network of hair-like elements named “trichomes” by maslov (1956) or “fl occulent microfabric” by riding & guo (1992) or “clotted micrite” by pratt (1995, p. 88). for details of these elements see for example maslov (1956, pl. 26, pl. 27, fi g. 3), riding & guo (1992, text-fi g. 1) and senowbari-daryan & flüg el (1993, text-fi gs. 2, 7). these elements were compared with the spongin protein of demosponges and tubiphytes was interpreted as a sponge by wang et al. (1994). as shown by senowbari-daryan & flügel (1993) this “fl occulent microfabric” belongs to primary mineralized elements and can hardly be compared with the spongin of sponges. such elements are also known from another enigmatic triassic microfossil called plexoramea (mello, 1977) which is interpreted as a fungus by flügel et al. (1988). it is noteworthy that such “trichomes” or “fl occulent microfabric” are totally lacking in jurassic – cretaceous crescentiella. the “cortex” of crescentiella is instead composed of oblique running laminae produced by the alternation of small and large crystals (pl. 6, figs. a–b, d; pl. 7, figs. d–e). pratt (1995, p. 92) named it as “dense micrite around foraminiferal tubes”. c) pustule-like protuberances (see senowbari-daryan & flügel, 1993, pl. 1, fi gs. 2–4, text-fi gs. 2, 7) at the surface of the palaeozoic t. obscurus were never observed in the jurassic c. morronensis. d) the oblique lamination, a characteristic feature of c. morronensis (crescenti) nov. comb. may occur in some representatives of triassic “tubiphytes”, but it is totally lacking in palaeozoic representatives, at least in t. obscurus. also flügel (1981, p. 133) mentioned that the apparent concentric structures, observable in cross sections of c. morronensis are lacking in t. obscurus. e) the internal cavity (foraminifera or tube of uncertain affi nity) of c. morronensis passes through the whole body and is not limited to individual segments as in most specimens of palaeozoic t. obscurus or t. carinthiacus. these differences justify the establishment of an independent genus for the jurassic – cretaceous microfossil, originally described as “tubiphytes” morronensis by crescenti (1969) introduced here as crescentiella n. gen. crescentiella n. gen. derivatio nominis: in honour of dr. uberto crescenti who described this fossil for the fi rst time. diagnosis: “corpo calcareo micritico di forma grossolanamente cilindrica, internamente percorso da un´esile cavita con diametro variabile e con strozzature poste a intervalli irregolari. in sezione sottile il corpo cilindrico (tubo), a diametro variabile e a contorni esterni mal delimitati, presenta un aspetto denso e scuro; ad un´analisi dettagliata mostra di essere costituito da sottilissimi strati micritici all´apparenza concentrici, fortemente ravvicinati tra loro” (generally cylindrical (single or gregarious colonies grown together) micritic calcareous bodies, internally crossed by a thin cavity of variable diameter and with narrowed zones located at uneven intervals. in thin sections, the cylindrical body (the tube) of variable diameter and poorly-delimited external outline appears as a dense and dark-coloured material; when investigated in detail, it consists of thin, densely packed micritic layers (produced by layers of small and large crystals) with a concentric display”. this diagnosis was given by crescenti (1969, p. 35) for the species t. morronensis, which is also valid for the genus crescentiella with some additional criteria, added here (see italics), as partly observed by sem. senowbari-daryan et al. (2007) introduced the genus crescentina, as a new name for “tubiphytes” morronensis. this is considered an invalid name because there is no appropriate reference to its basyonym. type species: tubiphytes morronensis crescenti, 1969. crescentiella morronensis forma morronensis (crescenti 1969) nov. comb. (figs. 1–3, 8; pl. 1, figs. a–i; pl. 2, figs. a–h; pl. 3, figs. a–g; pl. 4, figs. b–h; pl. 5, figs. b, d–h; pl. 6, figs. a–h) selected synonymy [for further synonymy before 1969 see schmid (1996)]: 1969 tubiphytes morronensis n. sp. – crescenti, p. 35–37, fi gs. 10, 20–22 1969 mikro-onkolithe – dragastan, pl. 21, fi g. 1–3; pl. 22, fi gs. 1–4 1972 nodophthalmidium – wagenplast, pl. 16, fi g. 4 1975 mikro-onkolithe – dragastan, pl. 18, fi g. 2; pl. 21, fi g. 2; pl. 22, fi g. 1; pl. 24, fi g.2; pl. 25, fi g. 1; pl. 33, fi g. 1 1975 onkoide – meyer, fi gs. 8–10 1979 tubiphytes obscurus maslov – mišík, pl. 1, fi gs. 13–15 1979 tubiphytes morronensis crescenti – chiocchini & mancinelli, pl. 3, fi g. 3; pl. 6, fi gs. 1–2 geologia croatica geologia croatica 61/2–3 188 1980 tubiphytes obscurus maslov – mišík & sykora, pl. 1, fi g. 11 1981 tubiphytes morronensis crescenti – flügel, p. 131, fi gs. 1–10 1981 oncoid with nodophthalmid foraminifera – flügel & steiger, fi gs. 17f–g 1986 tubiphytes morronensis crescenti – eliasova, p. 28, pl. 1, fi g. 1; pl. 2, fi g. 1 (synonymy) 1984 tubiphytes sp. – steiger & jansa, fi g. 6–2 1985 tubiphytes sp. – hüssner, p. 154, pl. 17, fi gs. 4–6 1986 tubiphytes morronensis crescenti – brachert, p. 243, pl. 42, fi gs. 2–3; pl. 43, fi g. 7 1987 tubiphytes morronensis crescenti – barattolo & pugliese, pl. 7, fi gs. 2–4, 7, 10; pl. 32, pl. 37, pl. 38, fi g. 1; pl. 40 1989 tubiphytes morronensis crescenti – lang, p. 232, pl. 60, fi gs. 7–8 1989 composite oncoid cf. tubiphytes sp. – matyszkiewicz, pl. 9, fi g. 5 1989 tubiphytes morronensis crescenti – pomoni-papaioannou et al., pl. 58, fi gs. 5–6 (also fi g. 7). 1990 tubiphytes morronensis crescenti – keupp et al., p. 155, pl. 21, fi gs. 4–5. non 1 990 tubiphytes cf. obscurus maslov – kuss, p. 68, pl. 20, fi g. 2; pl. 21, fi g. 9. 1991 tubiphytes morronensis crescenti – barattolo, pl. 1, fi gs. 4–5 1991 tubiphytes morronensis crescenti – altiner, pl. 6, fi gs. 4–8 1992 tubiphytes – brachert, pl. 43, fi g. 4; pl. 44, fi g. 10 1992 tubiphytes – matyszkiewicz & felisiak, pl. 38, fi gs. 2–4; pl. 39, fi g. 1; pl. 40, fi g. 1, 2 1992 tubiphytes morronensis – leinfelder, pl. 23, fi gs. 1, 5–6 1993 tubiphytes morronensis crescenti – leinfelder et al., p. 205, pl. 49, fi g. 4; pl. 40, fi g. 4; pl. 41, fi gs. 5–7 1994 tubiphytes morronensis crescenti – dragastan et al., pl. 3, fi g. 6 1994 tubiphytes morronensis crescenti – luperto sinni & masse, pl. 1, fi gs. 5–6 1994 “tubiphytes” morronensis crescenti – koch et al., pl. 22, fi gs. 3, 5–6 1994 tubiphytes sp. – matyszkiewicz & słomka, pl. 2, fi g. 3; pl. 4, fi g. 4; pl. 7, fi g. 2 1994 tubiphytes morronensis crescenti – senowbari-daryan et al., p. 235, pl. 11, fi gs. 9–11 1995 tubiphytes – pratt, fi g. 45.d–e 1996 tubiphytes – matyszkiewicz & krajewski, fi g. 10e 1995 tubiphytes morronensis crescenti – schmid, p. 306, fi gs. 5–13 1996 tubiphytes morronensis crescenti – schmid, p. 188, fi gs. 63–64, 96–97, 113 (non 105–112, 116) (synonymy) 1996 tubiphytes morronensis crescenti – santantonio et al., fi g. 15 1997 “tubiphytes” morronensis crescenti – flügel & flügel-kahler, pl. 24, fi gs. 4–5, 8 1997b tubiphytes – matyszkiewicz, fi g. 4 1998 tubiphytes morronensis crescenti – carras & georgala, pl. 42, fi g. 2. 1999 tubiphytes morronensis crescenti – richter et al., pl. 1, fi g. 1, 9 1999 tubiphytes morronensis crescenti – dupraz & strasser, pl. 12, fi g. 3 1999 tubiphytes sp. – scheibner & reijmer, pl. 16, fi g. 2–3 1999 tubiphytes obscurus maslov – blomeier & reijmer, pl. 20, fi g. 5 1999 “tubiphytes” morronensis crescenti – schlagintweit & ebli, pl. 2, fi g. 5; pl. 4, fi g. 7; pl. 12, fi gs. 4–5 2000 tubiphytes morronensis crescenti – schmid & henssel, p. 50, fi gs. 4–5, 7–10 2000 “tubiphytes” morronensis crescenti – bucur & onac, p. 15, pl. 2, fi g. 9 2000 “tubiphytes” morronensis crescenti – săsăran et al., p. 453–456, pl. 2, fi g. 5 2000 tubiphytes – krajewski, fi g. 11 2001 tubiphytes morronensis crescenti – helm & schülke, p. 101, fi gs. 2–4 2001 “tubiphytes” morronensis – krajewski, fi g. 10 2001 tubiphytes – neuweiler, mehdi & wilmsen, pl. 39, fi gs. 4–5 2001 “tubiphytes” morronensis crescenti – săsăran et al., p.37, 39, 40, pl. 10, fi g. 4 2001 tubiphytes morronensis crescenti – volk et al., pl. 10, fi g. 3/2; pl. 13, fi g. 1–2 2002 tubiphytes – dupraz & strasser, fi g. 14.d 2002 “tubiphytes” morronensis crescenti – scherze & höfling, p. 194, pl. 1, fi g. 5 2003 tubiphytes morronensis crescenti – burza & dragastan, pl. 1, fi g. 2 2003 tubiphytes morronensis crescenti – dragastan & richter, pl. 1, fi g. 5t 2003a tubiphytes – fürsich et al., pl. 35, fi g. 5t 2003b tubiphytes – fürsich et al., pl. 31, fi g. 7–8 2003 tubiphytes – olóriz et al., fi g. 11.g 2003 “tubiphytes“ morronensis crescenti – schlagintweit & gawlick, pl. 2, fi g. 1–2 2003 a „tubiphytes“ morronensis crescenti – schlagintweit et al., pl. 3, fi g. 8; pl. 4, fi g. 15 2003 b „tubiphytes“ morronensis crescenti – schlagintweit et al., pl. 1, fi g. 3; pl. 2, fi g. 7 2003 “tubiphytes“ morronensis crescenti – uta & bucur, pl. 3, fi g. 1–2, 5 2004 tubiphytes morronensis crescenti – flügel, pl. 99, fi gs. 7 2004 tubiphytes sp. – matyszkiewicz et al., pl. 6, fi g. 1/t 2004 “tubiphytes” morronensis crescenti – schlagintweit, pl. 1, fi g. 9/2; pl. 2, fi g. 2 2005 “tubiphytes” morronensis crescenti – gawlick et al., fi g. 11.3 geologia croaticababa senowbari-daryan et al.: crescentiella, a new name for “tubiphytes” morronensis crescenti, 1969... 189 2005 “tubiphytes” morronensis crescenti – helm, p. 80, pl. 8, fi g. 1 2005 “tubiphytes” morronensis crescenti – radoičić, p. 33, pl. 9, fi g. 7 2005 “tubiphytes” morronensis crescenti – schlagintweit et al., p. 80, fi g. 18c (pars), fi g. 31 (pars), fi g. 70b, 77a–c 2006 “tubiphytes” morronensis crescenti – gawlick & schlagintweit, fi g. 4e–f 2006 “tubiphytes” morronensis crescenti – gawlick et al., fi g. 10.4, 11.9 2006 tubiphytes sp. – matyszkiewicz et al., fi g. 5b description: a detailed description of crescentiella morronensis is given by crescenti (1969), flügel (1981) and particularly by schmid (1995). a reconstruction of c. morronensis is given by schmid (1995) and a similar reconstruction by leinfelder et al. (1996). the thickness of the “cortex” or “envelope”, respectively the difference between the outer and inner diameter of c. morronensis seems to depend on the light as presented by schmid (1995) and one more by leinfelder et al. (1996), but not confi rmed by other studies (dupraz & strasser, 2002, p. 463). here the general characteristics and additional observations are briefl y summarized. morphologically, the length of c. morronensis is a few mm (maximum 10 mm, fig. 1), usually single (fig. 2; pl. 1, figs. a–e; pl. 4, figs. b–c, f–h), rarely dichotomously “branched” (pl. 3, fig. g), with a diameter of about 0.4–1.3 mm. according to hennsel et al. (2002), the branched specimens are in fact individual specimens of foraminifera that formed as a consequence of overgrowth. this statement corresponds to our observations. fi gu re 1: section through numerous specimens of crescentiella morronensis forma morronensis (crescenti) showing the abundance of this fossil. drawn from a polished slab of “plattenkalk” from southern germany. the largest specimen of crescentiella morronensis forma morronensis is less than 10 mm. specimens of tubiphytes are embedded without any recognizable orientation in micritic sediment. areas within dotted lines and marked with a number 1 are micritic areas without tubiphytes, areas marked with a number 2 are cement, and areas marked with a number 3 are sponge fragments. fi gu re 2: crescentiella morronensis forma morronensis (crescenti) from the upper jurassic of the northern calcareous alps. a) axial longitudinal section through a specimen showing several, amphora-like chambers of internal foraminifera that grows lying on the substrate during the junior stage (here: actinostromarid “stromatoporoid”) and later becomes erect. the initial chambers (arrow) do not show encrustations by cyanobacteria. the oblique lamination of the surrounding “cortex” is barely recognizable. compared with fi g. c the amphora-like chambers and also their “necks” are very short. b) axial longitudinal section through a specimen showing the internal tube or poorly chambered(?) foraminifera surrounded by a dark “cortex”. within the “cortex” numerous small, mainly spherical fragments are embedded. c) longitudinal section through a specimen showing the amphora-like chambered foraminifera with a long neck and without distinct encrustation by cyanobacteria. arrow indicates a specimen of worm tube merciella? dacica dragastan. note that specimens a and b are from platform margin deposits, contradicting the trend of depth-decreasing width of the “cortex” proclaimed by schmid (1996). geologia croatica geologia croatica 61/2–3 190 plate 1 a–i crescentiella morronensis forma morronensis (crescenti) upper jurassic plassen carbonate platform and barmstein limestones of the northern calcareous alps, austria a longitudinal section showing the internal object cut marginally and the surrounding “cortex”. numerous inclusions are within the “cortex”. b longitudinal section illustrating the internal foraminifera with amphora-like chambers and the surrounding fi nely laminated “cortex”. in the basal portion there seems to be another coiled foraminifera. c longitudinal section through a similar specimen to fi g. b. d longitudinal to oblique section exhibiting the small foraminifera with amphora-like chambers in the centre surrounded by a very thick laminated “cortex”. the “cortex” shows diff erent generations, recognizable by a diff erent contrast and structure. some globular inclusions are embedded within the laminated “cortex”. the large globular inclusion (sponge rhaxe) is located at the surface of the foraminifera and embedded within two crust generations. e longitudinal section through a specimen exhibiting the foraminifera as a core. the foraminifera was growing in a recumbent position during the initial stage, but erect and growing upward during the latter stage. note the very thick laminated “cortex” and a spherical inclusion at the end of the foraminifera. the contrast within the encrustation indicates two generations for the formation of the “cortex”. f sections through several specimens. the specimen in the centre shows tubiphytes at the edges of the aggregate with crescent-like objects (foraminiferal chambers?) within the encrustation. g oblique cross section showing the calcite fi lled core in the centre and the thick encrustation with polygonal formed inclusions (bryozoans?) within the encrustation. h section through a specimen with an annulated large object (foraminifera?) and surrounding encrustation. an echinid spine is embedded as an inclusion within the encrustation. i cross section through a specimen showing some small spherical elements and two sessile foraminifera embedded within the cyanophycean crust. geologia croaticababa senowbari-daryan et al.: crescentiella, a new name for “tubiphytes” morronensis crescenti, 1969... 191 geologia croatica geologia croatica 61/2–3 192 plate 2 a–h crescentiella morronensis forma morronensis (crescenti) upper jurassic of poland a encrustation of a siliceous sponge fragment (right) with crescentiella (small cavity left and encrustation with darker contrast) and another undeterminable fragment (large cavity left) by further cyanophyceans. b encrustation of foraminifera – (small cavity in the center) with some undeterminable fragments embedded as inclusions within the “cortex”. the oblique running lamination in longitudinal section appears (here in cross section) as weakly concentric lines. c a specimen exhibiting the foraminifera with amphora-like chambers in the centre. crescentiella is colonized by other organisms (foraminifera, bryozoans) (for magnifi cation see fi g. d). d magnifi cation from fi g. c shows the foraminifera with a recognizable wall in the centre and encrustation of the foraminifera by a cyanophycean. the second foraminifera (arrow) is embedded at the margin of the encrustation. e a specimen cut in cross section surrounded by bryozoans. without a recognizable boundary the cyanophycean crust continues around the bryozoans and penetrates partly into the bryozoan cavities. f oblique cross section shows two chambers of foraminifera in the axial region encrusted by cyanophyceans. numerous small and calcite fi lled cavities (sessile foraminifera?) and a large component (bivalve?) are embedded within the “cortex”. the “cortex” is colonized by bivalves (left). g longitudinal section through a specimen exhibits the chambered foraminifera in the axial region and the oblique laminae of the “cortex”. h similar to fi g. g. geologia croaticababa senowbari-daryan et al.: crescentiella, a new name for “tubiphytes” morronensis crescenti, 1969... 193 geologia croatica geologia croatica 61/2–3 194 plate 3 a–g crescentiella morronensis forma morronensis (crescenti) upper jurassic (“treuchtliner marmor”) of southern germany a longitudinal cross sections through several specimens of crescentiella morronensis forma morronensis. small arrows indicate the encrustation of other biogenic fragments (mainly thin shells) and a specimen of trocholinid foraminifera (large arrow) by most probably the same cyanophyceans. b encrustation (partly) of a branched object by cyanophyceans. arrow indicates the amphora-like chamber of the encrusted foraminifera. white points indicate the boundary of crescentiella with the surrounded sediment. c cross sections of two crescentiella morronensis forma morronensis (crescenti) specimens surrounded by bryozoans. cyanobacterian crust of crescentiella continues as an encrustation partly on bryozoans (arrows). d section through three specimens of crescentiella morronensis forma morronensis and encrustation of other large biogenic fragments (large arrow) and small thin shells (small arrows) by identical cyanophycean crusts. e longitudinal to oblique section through a specimen of crescentiella morronensis forma morronensis (crescenti). the encrustation contains an amphora-like chambered foraminifera and a large (biogenic?) fragment. f longitudinal section through a specimen of crescentiella morronensis forma morronensis (crescenti). arrow indicates a biogenic fragment encrusted by the cyanophyceans. g several cross and a longitudinal section through a dichothomously “branched” specimen of crescentiella morronensis forma morronensis (crescenti) with clearly recognizable oblique laminations. white arrow indicates a shell fragment encrusted by identical cyanophyceans. black arrows indicate incomplete or non encrusted tubes with the same diameter as the totally encrusted tubes within the crescentiella. geologia croaticababa senowbari-daryan et al.: crescentiella, a new name for “tubiphytes” morronensis crescenti, 1969... 195 geologia croatica geologia croatica 61/2–3 196 c. morronensis is composed of two parts: a) internal part, usually as amphora-like chambered foraminifera or cylindrical tube, fi lled with calcite cement, appearing white in transmitted light, and b) a thick and oblique laminated external part, appearing dark in transmitted light. a) the internal part was a cavity, later fi lled with calcite cement, representing a cylindrical tube (fig. 2b; pl. 4, fig. b; pl. 5, figs. d–f), or usually with amphora-like chambered foraminifera (figs. 2a–b; pl. 1, figs. b, d–e; pl. 2, figs. c–d; pl. 3, fig. e; pl. 4, figs. g–h; pl. 6, figs. g–h) or even bioclasts (lang 1989, p. 32). the chamber length of the foraminifera is variable, some with a short “neck” (fig. 2a; pl. 2, fig. d) and others with a long “neck” (fig. 2c; pl. 4, fig. g) of the amphora-like chambers. the chambered cavity is interpreted as miliolid foraminifera “nodophthalmidium” (wagenplast, 1972; schmidt-kahler, 1962; flügel, 1981; schmidt, 1995), or “nubeculinella” (fritz, 1958; leinfelder et al., 1996). further interpretations of different authors are listed in flügel (1981, p. 127). because of differences in the size of the internal foraminifera, brachert (1986, p. 243) considers the possibility of a different subspecies. the cylindrical tube is of uncertain affi nity. as illustrated in pl. 3, figs. a, d, g, and pl. 4, figs. e–f, besides c. morronensis other objects in the same microenvironment, e. g. thin shell fragments, may be encrusted partly or completely as oncolites by a dark cortex that is identical to the cortex of crescentiella. some tubes, that may build the internal cavity of crescentiella, are encrusted only on one side or are incomplete (fig. 2c; pl. 4, fig. d; pl. 5, figs. b, e). for instance, pratt (1955, fi g. 45e) illustrated a specimen of “tubiphytes” (= crescentiella) together with a naked and non encrusted tube, naming it “tubular foraminifera”. the wall of the internal cavity (tube or foraminifera) is distinct and totally different from the surrounding “cortex”. the boundary of the wall of the internal object (foraminifera or tube) with the external part (“cortex”) is sharp, (pl. 6, figs. a–e, g; compare also flügel, 1981, fi g. 10). the mineralogical composition of the wall of this tube or foraminifera is mg-calcite with a microgranular structure (fig. 3; pl. 6, figs. c–d). the thickness of the wall is about 30–40 mm (pl. 6, figs. d–e). b) the external part (“cortex” or “envelope”), is much thicker than the internal part (cavity plus the wall of cavity), and appears dark in transmitted light. the “cortex” appears lighter than the wall of the internal part in transmitted light. the distinct structure of the “cortex” results from its obliquely oriented fi ne lamination (“micropeloidal struktur” of schmid, 1995, p. 306; or “dense micrite around a foraminiferal tube” of pratt, 1995, p. 92), visible in thin section and also by sem (fig. 2a; pl. 1, fig. e; pl. 2, figs. c–d; pl. 3, figs. e–g; pl. 4, fig. h; pl. 6, fig. f). the lamination is produced by the different size and orientation of the crystals within the “cortex”, as shown by sem-photomicrographs (fig. 3; pl. 6, fig. f). the lamination appears as concentric lines in cross sections (pl. 2, figs. b, e; pl. 6, figs. 1–2; see also flügel, 1981, fi g. 2). specimens of crescentiella morronensis from epicontinental deposits in southern germany and other localities are almost always single individuals, dichotomously “branched” specimens are very rare (pl. 3, fig. g). “colonial” forms, connected with others by the external part (“cortex”) are extremely rare (see flügel, 1981, fi g. 3; leinfelder et al., 1993, pl. 41, fi g. 7; schmid, 1995, fi g. 13). however, colonial forms are abundant in open marine environments of the tethyan realm, reaching sizes of several centimetres and are described here as c. morronensis forma colligaris nov. forma. crescentiella morronensis forma colligaris nov. forma (figs. 4–7; pl. 4, fig. a–d; pl. 5, fig. a, c, h; pl. 7, figs. a–e; pl. 8, figs. a–b, d–e) 1995 “tubiphytes” morronensis. kolonie in massiger wuchsform – schmid, fi g. 13 (same specimen as illustrated in leinfelder et al., 1996) 1996 “tubiphytes” nodule composed of several specimens – leinfelder et al., pl. 41, fi g. 7 derivatio nominis: colligo (lat. = bind together). because of individual specimens that are bound together by cyanophycean crusts. fi gu re 3: section through a specimen of crescentiella morronensis forma morronensis (crescenti) and the reconstruction of the internal cavity as foraminifera (nodophthamidium or nubeculinella) with four chambers. the magnifi cation shows the wall of the foraminifera and boundaries to the secondary cement of the chamber interiors and the laminated structure of the surrounding “cortex”. the wall of the foraminifera is composed of small crystals (microgranular structure), without any orientation of the crystals. the surrounding “cortex” is characterized by the alternation of large and small crystals producing the oblique lamination. the white areas within the “cortex”, (f) are inclusions of organisms or inorganic fragments. because of the reduced thickness of laminae around the aperture of the foraminifera, they appear moderately darker here. schematic, not to scale. geologia croaticababa senowbari-daryan et al.: crescentiella, a new name for “tubiphytes” morronensis crescenti, 1969... 197 diagnosis: colonial form of crescentiella morronensis (crescenti). the individual specimens are connected with each other by bridging of the same cyanophycean crusts forming the “cortex”. the distance between individual specimens may be more than ten times the diameter of individual specimens. fi gu re 4: crescentiella morronensis forma colligaris nov. forma from the upper jurassic (oxfordian – kimmeridgian) esfandiar formation in the shotori mountains, iran. the grass-like colonies of gregarious and individual specimens are in life position. they are mainly bridged by cyanophycean crusts. polished slab (for thin section photographs see pl. 4, figs. a–d). fi gu re 5: crescentiella morronensis forma colligaris nov. forma from the upper jurassic (tithonian) of the madonie mountains, sicily. the longitudinal section shows several tubes as a core, bridged by cyanophycean crusts. the tubes are covered by crust laminae passing through several tubes in a lateral direction. the tubes of the uppermost part are weak and incompletely encrusted and no distinct laminae are recognizable. the distance between the individual cores (tubes) is more than 2 mm. the encrustation around the cores is stronger than between the cores (drawn from pl. 5, fig. a). fi gu re 6: crescentiella morronensis forma colligaris nov. forma from the upper jurassic (tithonian) of the madonie mountains, sicily. longitudinal section from the colony shows the growth stages and the kind of bridging of the individual specimens by the cyanophycean crusts. dark areas are without encrustation or are totally recrystallized areas within the cyanophycean crusts (drawn from pl. 5, fig. c). fi gu re 7: crescentiella morronensis forma colligaris nov. forma from the upper jurassic (tithonian) of the madonie mountains, sicily. section of an individual specimen shows the growth stages and the core, its wall (dark) and the blocky cement within the core (drawn from pl. 8, fig. d). geologia croatica geologia croatica 61/2–3 198 plate 4 a–d crescentiella morronensis forma colligaris nov. forma upper jurassic (oxfordian-kimmeridgian) esfandiar formation of the shotori mountains, ne iran a longitudinal to oblique section through numerous specimens that are connected with others by bridging of cyanophycean crusts. the internal cavities are composed of tubes of uncertain affi nity. some tubes (arrows) are not or incompletely encrusted by cyanophyceans. the polished slab of the same colony is illustrated in fig. 4. b magnifi cation of a “specimen” or “branch” from the same “colony” in fi g. a showing the internal cavity composed of cylindrical and non chambered tube of uncertain affi nity. c longitudinal section exhibiting several tubes or chambered foraminifera as a core encrusted by cyanobacteria. small arrows indicate a curved tube which is encrusted only on one side. large arrows show the interruption of crescentiella by a large calcitic object. d view of two tubes (from the same thin section in fi g. a or b) with or without incomplete encrustation by cyanobacteria. diameter of the tube corresponds to the tubes illustrated in fi gs. a–b. e–h crescentiella morronensis forma morronensis (crescenti) upper jurassic “treuchtlinger marmor” of southern germany e sections through a few specimens of crescentiella morronensis forma morronensis (in the centre and the right side) and numerous oncolites. the cores of the oncolites are fragments of thin shells. there are no diff erences in encrustation between the oncolites and crescentiella; only the cores are diff erent. f section through numerous individual specimens of crescentiella morronensis forma morronensis with almost the same size, but without bridging by cyanophyceans as in c. morronensis forma colligaris nov. forma. white arrows indicate oncolites with encrustation of shell fragments on both or only one side. g longitudinal section through a specimen with clearly recognizable amphora-like chambered foraminifera. compared with the specimen illustrated in fig. 2a, the height of the amphora-like chambers or the “necks” of the chambers are longer. h section through a longitudinal specimen growing on another specimen of crescentiella morronensis forma morronensis. the core of the upright growing specimen seems to be broken in the middle. geologia croaticababa senowbari-daryan et al.: crescentiella, a new name for “tubiphytes” morronensis crescenti, 1969... 199 geologia croatica geologia croatica 61/2–3 200 plate 5 a–c crescentiella morronensis forma colligaris nov. forma upper jurassic reef limestones of the madonie mountains, sicily a longitudinal section through a colony exhibiting several tubes surrounded and bridged by cyanophycean crusts. diff erences in contrast indicate the growing stages of the crust building organisms. black arrows indicate the tubes without or incompletely encrusted by cyanophyceans. for sem-photomicrographs see pl. 7. compare also fig. 5. b section through several specimens. arrows indicate the tubes without or incomplete encrustation by cyanophyceans. the cores of crescentiella are cylindrical tubes and not chambered foraminifera. c longitudinal to oblique section through numerous tubes encrusted and bridged by cyanophyceans. the clearly recognizable laminae are interpreted as growth stages of cyanophyceans and possibly tubes. arrows indicate the tubes without encrustation, but with the same size as those with encrustation. d–h crescentiella morronensis forma morronensis (crescenti) upper jurassic reef limestones of the madonie mountains, sicily d longitudinal section through a specimen showing the internal tube with thick encrustation on the lower part, but with a thin wall (without encrustation) on the upper part. e section through one (or two) tube(s) with weak encrustation on the upper part, but with complete encrustation on the lower part. f section through a specimen with at least fi ve diff erent growth stages (or types) of encrustation refl ected by the diff erent contrast marked by small arrows. the encrustation of younger stages is weak or incomplete. within the last two encrustation stages the tube is either lacking or has not been bisected. g similar section to fi g. f showing at least two growth stages. arrows indicate the tubes without encrustations. h cross section through several individual specimens grown together by the bridging of cyanphyceans. the contrast variation of encrustations indicates the growth stages. arrows indicate the tubes, still without encrustation. geologia croaticababa senowbari-daryan et al.: crescentiella, a new name for “tubiphytes” morronensis crescenti, 1969... 201 geologia croatica geologia croatica 61/2–3 202 plate 6 a–h sem-photomicrographs of crescentiella morronensis forma morronensis (crescenti) upper jurassic “treuchtinger marmor” of southern gemany. a cross section of a specimen showing the small axial core and the thick external part (“cortex” or “envelope”). laminations in cross section, appearing as concentric laminae, are barely recognizable. for magnifi cation of the axial region see fi g. c. b similar section to fi g. a. the concentric laminae are clearly recognizable. for magnifi cation see fi g. d. c magnifi cation of fi g. a showing the axial part (core) with a large calcite crystal within the internal object (most probably a foraminifera). the wall of the internal object is relatively thick (about 15 mm, see scale) and is composed of small crystals (microcrystalline). d magnifi cation from fi g. b showing the wall of the axial object (most probably a foraminifera) composed of crystals of approximately 2 mm. the boundary of the wall to the internal calcite cement fi lling and the outer “cortex” is distinctly sharp. for magnifi cation see fi g. e. e magnifi cation from fi g. d showing the wall of the internal object composed of small and equal sized crystals (microcrystalline structure). f longitudinal section of part of a specimen showing the oblique lamination with alternating layers of large and small crystals. g magnifi cation from fi g. h shows the chambered object (most probably a nodophthalmidium foraminifera), the microcrystalline wall of the foraminifera and the lamination of the surrounding cortex. h oblique section through a specimen showing the chambered internal object (most probably a foraminifera) and the poorly recognizable laminated thick cortex. for magnifi cation see fi g. g. geologia croaticababa senowbari-daryan et al.: crescentiella, a new name for “tubiphytes” morronensis crescenti, 1969... 203 geologia croatica geologia croatica 61/2–3 204 plate 7 a–e sem-photomicrographs of crescentiella morronensis foma colligaris nov. forma upper jurassic reef limestones of the madonie mountains, sicily. a magnifi cation from fi g. b showing the tube surrounded by cyanophyceans. the diff erent growth stages are easily recognizable. for magnifi cation of the area marked with a white quadrangle see fi g. c. b magnifi cation from the specimen illustrated in pl. 8, fig. d. section through a “member” of a colonial form showing the diff erent growth stages of cyanophyceans and the internal tube. in the lower part (right in the photograph) there are only the cyanophyceans (for magnifi cations see fi gs. a, d–e, for the area marked with white quadrangle see fi g. c). c magnifi cation from fi g. b (or a: quadrangle) shows the microcrystalline wall of the tube (foraminifera?) having a thickness of about 30–40 mm. the crystal sizes of the wall are smaller than that of the cortex. d magnifi cation from fi g. b shows the tube wall with small crystals (upper part of the photograph, marked with arrows) and the laminated structure of the cortex, produced by the diff erent crystal sizes (compare fi g. e). e magnifi cation of the area, marked with quadrangle in fi g. d showing the individual laminae with diff erent sized crystals. geologia croaticababa senowbari-daryan et al.: crescentiella, a new name for “tubiphytes” morronensis crescenti, 1969... 205 geologia croatica geologia croatica 61/2–3 206 plate 8 a–b, d–e crescentiella morronensis forma colligaris nov. forma upper jurassic reef limestones of the madonie mountains, sicily a magnifi cation of the area marked with a quadrangle in the top of fi g. d shows the end stage of the specimen. b longitudinal to oblique section shows several internal tubes encrusted and bridged together by cyanophyceans. the colony grows upon another organism. d sem-microphotograph of a “member” of the same colony illustrated in pl. 5, fig. a showing the internal tube and laminated cortex. for magnifi cation of areas marked with a black quadrangle see pl. 6, with a white quadrangle see fi g. a and also fi g. e (compare also fig. 7). e magnifi cation of the wall of the specimen illustrated in fi g. d showing the small crystals of the tube wall and the large crystals of the tube interior. c labes atramentosa upper jurassic of the northern calcareous alps c labes atramentosa eliasova. longitudinal section showing the coiled tube(s) and the internal cavity fi lled with cement. this specimen is atypical. very long, usually low conical forms are prevalent. geologia croaticababa senowbari-daryan et al.: crescentiella, a new name for “tubiphytes” morronensis crescenti, 1969... 207 geologia croatica geologia croatica 61/2–3 208 description: the gregarious specimens of this crescentiella morronensis forma colligaris are composed of several individual specimens building nodule-like colonies of several centimetres in diameter (up to 10 cm and more). the individual specimens are connected with each other by continuation of the fi nely laminated cyanophycean crust forming the “cortex” (figs. 4–6; pl. 4, fig. a; pl. 5, figs. a, c). the distance of the individual internal cavity, bridged by cyanophyceans, may be several millimetres. the individual layer of the cyanophycean crusts (“cortex”) may run down, building “mini-tepeelike” structures (figs. 5–7; pl. 7, figs. a–b; pl. 8, fig. d). the “cortex” between two neighbouring specimens is not formed by internal foraminifera or tubes, because a line, produced by growing together is totally lacking. the walls of the internal tube or foraminifera (fi ne micritic crystals: pl. 7, fig. c; pl. 8, figs. a, e) and the laminated microstructure of the cortex (pl. 7, figs. d–e) are the same as previously described for c. morronensis forma morronensis (crescenti). discussion: according to leinfelder et al. (1996) the outer diameter of crescentiella (diameter of “cortex”) is dependent mainly on light for the algal symbiosis. according to these authors in water depths of about 5–40 m (inner ramp), the cortex is very thick, in depths of about 40–80 m (middle ramp) the thickness is moderate, while at depths of 80–120 m (outer ramp) the thickness is thin and in depths of more than 120 m the internal foraminifera is without the “cortex” (compare also schmid, 1996, fi g. 119). this statement of leinfelder et al. (1996) was not confi rmed by dupraz & strasser (2002, p. 463). according to schmid (1995) the “colonial” forms refl ect the ecological conditions growing in low energy environments on soft substrates (see also leinfelder et al., 1996). this statement can not be confi rmed for open marine upper jurassic reef environments where both forms of crescentiella (“colonial” and individual) occur together, with corals and other reef builders in the madonie mountains, sicily and the shotori mountains, iran. in both localities the gregarious and “colonial” crescentiella, (reaching a nodular size of up to 10 cm and more), are abundant (fig. 4). the core (axial cavity) of such crescentiella are usually tubes (pl. 4, figs. a, d; pl. 5, figs. a–c), chambered foraminifera are usually in individual forms (pl. 5, figs. f–g). sem-investigations of both types of crescentiella from upper jurassic epicontinental carbonates (southern germany: pl. 6, figs. a–h), and open marine upper jurassic deposits (sicily: pl. 7, figs. a–e), show the same microstructure of the wall of the internal core (tube or foraminifera) and the surrounding crust (“cortex”). we found a similar micro structure of both environmental types from the upper jurassic of sicily and southern germany. also there are no differences between the wall structure of the cylindrical tube and the chambered cavity (foraminifera). occurrence: the stratigraphic range of crescentiella morron ensis (crescenti) is given as being from the middle jurassic to the upper cretaceous, or possibly the palaeocene, by schmid (1996, p. 189). the late cretaceous or even palaeocene occurrences are questionable and cannot be confi rmed here. it is an abundant fossil in upper jurassic shallow water carbonates, particularly in epocontinental environments of the tethyan realm. it occurs throughout the cretaceous deposits, but not as abundant as in the jurassic (moussavian, 1992). crescentiella is known from numerous upper jurassic localities of northwest and central tethys (see synonymy). scheibner & reijmer (1999) reported its occurrence in the lower jurassic of morocco. interpretation: the systematic position of tubiphytes maslov is much disputed in the literature. it is variously interpreted as: cyanophyceans (maslov, 1956; croneis & toomey, 1965; flügel & flügel-kahler, 1980), rhodophyceans (flügel, 1966; kochansky-devidé, 1970); algae of uncertain systematic position (johnson, 1963; homann, 1972), sponges (ott, in kraus & ott, 1968; riding & guo, 1992; wang et al., 1994) and hydrozoans (rigby, 1958). vachard et al. (2001) interpreted tubiphytes maslov “as a free cyanobacterium or alga developed symbiosis with other organisms”. babcock (1986, p. 13) interpreted tubiphytes as problematicum “that may belong to an extinct phylum”. payne et al. (2006) described the abundance of “tubiphytes” in the middle triassic (anisian) reef complex from guizhou province, southwest china. the authors illustrated numerous specimens of a “tubiphytes framework”, and in fi g. 18 several cross sections of “tubiphytes” with the “presence of small spore-like structures (~50–75 mm diameter) contained within larger spheres (~500 mm diameter)”. the small spheres are interpreted as “algal sporangia” by payne et al. (2006) and consequently “tubiphytes” as alga. such small spheres are also described in anisophytes aggtelekensis (schloz) by senowbari-daryan & velledits (2007). “tubiphytes” of payne et al. (2006) and also those of lehrmann et al. (1998) from the same province can not be assigned to tubiphytes sensu maslov (1956). discussion about the assignment of such “tubiphytes” is given by senowbaridaryan & velledits (2007) and a revision of triassic tubiphytes is in preparation by senowbari-daryan. the systematic position of crescentiella morronensis (cre scenti) – like tubiphytes or similar organisms – is also uncertain. for interpretation of the whole organism (internal cavity and surrounding “cortex”) as favoured by bernier (1984), for “microoncolites” see dragastan (1969), meyer (1975), kott (1989) and flügel & steiger (1981). oncolites are defi ned as the encrustation of biogenic or abiogenic fragments by other organisms, mainly cyanobacteria (for a detailed defi nition see flügel, 2004, p. 100). the interpretation of meyer (1977), flügel (1981), and leinfelder et al. (1993), that the whole organism represents a symbiosis between foraminifera and cyanobacteria or encrusting of foraminifera by algae or cyanobacteria during the life time of the internal object, is different to the interpretation as microoncolites. this defi nition does not justify the classifi cation of crescentiella as a “special oncolite”. schmid (1995) recognized the laminated structure of the “cortex” naming it as “micropeloidal”. based on such “migeologia croaticababa senowbari-daryan et al.: crescentiella, a new name for “tubiphytes” morronensis crescenti, 1969... 209 cropeloidal” structure of the “cortex” schmid (1995) excluded a cyanophycean nature for the formation of the “cortex”. another reason for schmid to exclude such an interpretation of the “cortex” was that no other components except crescentiella morronensis (crescenti) became encrusted. our observations contrast schmid´s statement (see below). in summary, schmid (1995) interpreted crescentiella morronensis as the symbiosis of foraminifera with endobiotic algae (possibly dinophyceans, rhodophyceans or cyanophyceans) which are responsible for the formation of the external wall (“cortex”). the following criteria are contraindicative to the statement of schmid (1995): 1. the sem photomicrographs of the “cortex” in both individual and colonial forms of crescentiella (fig. 3; pl. 6, figs. a–b, f; pl. 7, figs. d–e) show that the “mikropeloide” (micropeloids) of schmid (1995) in reality represent large crystals alternating with small crystals, thereby producing the fi nely laminated structure of the “cortex”. we interpret the large crystals as being abiogenic, the small crystals as biogenic, as produced by cyanophyceans. 2. we can not confi rm the statement of schmid (1995, p. 307), that “außerdem umhüllt die mutmaßliche “cyanobakterie” nie etwas anders als “t.” morronensis, wie etwa bioklasten” (in addition the presumable cyanobacteria never encrusted objects other than “t.” morronensis, e.g. bioclasts). as shown in our material (pl. 1, figs. d, f–i; pl. 2, figs. a–f; pl. 3, figs. a–g; pl. 4, fig. e), there are not only encrustations of foraminifera by cyanophyceans, but also of other biogenic fragments, such shell fragments, sponges, bryozoans, echinoderm remains, etc. by the same or similar cyanophycean activity. encrustation of tubes of uncertain taxonomic position is also abundant. fragments of thin shells are also mostly encrusted by cyanophyceans, building the microoncolites of may er (1975) and kott (1989). the “microoncolite” interpretation (dragastan, 1969; kott, 1989) of crescentiella morronenis was denied by schmid (1995), because the cyanobacteria do not surround the apertures of foraminifera and it (cyanobacterium) does not occur alone. in fact, the cyanobacteria do not occur alone or almost usually with foraminifera or tubes, because as a symbiont they need a substrate to grow on. foraminiferal tubes and shells serve as a substrate for the encrustation of cyanobacteria. foraminifera particularly seem to be the most favoured substrate. fig. 8 shows the possibile growth process between the chambered foraminifera and the encrusted cyanophyceans. 3. also inclusion of biogenic and abiogenic components (e. g. coccolithophorids, see flügel, 1981, fi g. 8; possibly “calcispheres”, see volk et al., 2001, pl. 13, fi g. 1; different biogenic components, see fig. 2.b; pl. 1, figs. d–h; and foraminifera, pl. 1, fig. i) embedded within the “cortex”, do not support schmid´s interpretation of the “cortex” as the external wall of the foraminifera. 4. we observed not only the inclusion (or agglutination in foraminiferal terminology) of detrital bioclasts but also encrusting foraminifera between the micritic sheets of the “cortex” obviously refl ecting the life position during the time of laminae formation (pl. 1, fig. i). 5. the extremely thick “cortex” (pl. 5, figs. a, c; pl. 7, figs. a–b; pl. 8, fig. d; compare figs. 5–6) and its strongly downward turning do not support its formation by the internal organism (foraminifera or tube). 6. the fi ne lamination of the “cortex” indicates that the individual laminae were formed successively one after the other. such permanent formation of the wall also argues against its formation by the internal foraminifera, tube or other object. 7. the encrusting of different objects (foraminifera, tubes, shells etc.) by a thick crust (“cortex”) in the same environment, as shown e.g. in pl. 4, figs. e–f, is in contrast to the interpretation of the whole organism as a foraminifera as done by schmid (1995). instead, these criteria support the participation of a second organism for the formation of the cortex of crescentiella. this organism is of a cyanophycean nature. the complete encrustation of tubes or shells as an internal part of crescentiella supports the interaction of different objects and cyanophyceans. the oblique lamination of the “cortex”, produced by different crystal sizes, does not indicate the formation of different layers at the same time, but successively. this observation also supports the interpretation of crescentiella as the interaction of two different organisms: foraminifera, tube or shells serving as a core or substrate for cyanobacteria. the crusts of cyanobacteria serve as a stabiliser and support the internal object in a growth position and enable its successive growth (see fig. 8). we interpret the cortex of crescentiella morronensis as crusts of cyanophyceans and the whole body as representing a symbiosis between a foraminifera or indeterminable tubes and cyanophyceans. foraminifera, tubes or other objects serve as a substrate for the growth of cyanophyceans. the crust of cyanophyceans stabilizes and enables the further growth of the foraminifera or tube of uncertain systematic position. fi gu re 8: possible formation process of crescentiella morronensis forma morronensis (crescenti) by interaction between the two symbionts (foraminifera and cyanophyceans). after formation of the fi rst chamber of the foraminifera and its encrustation by the cyanophyceans, the formation of the second chamber and its encrustation follows. this process continues to build crescentiella, composed of multichambered foraminifera as a core and a surrounding crust produced by cyanophyceans. after the death of the foraminifera the whole test is encrusted by the cyanophyceans. schematic, not to scale. geologia croatica geologia croatica 61/2–3 210 labes atramentosa eliasova, 1986 (pl. 8, fig. c) 1986 labes atramentosa n. gen., n. sp. – eliasova, p. 110, pl. 1–2, pl. 2 (synonymy) 1986 „nubeculinellen-riffchen“ – brachert, pl. 42, fi g. 1 1996 “tubiphytes”-kamin (tubiphytes chimney) – schmid, fi gs. 102–112 1996 “tubiphytes” morronensis colony – leinfelder et al., fi g. 4 2005 labes atramentosa eliasova – schlagintweit et al., p. 75, fi g. 69a., b, fi g. 70a remarks: because this organism is mentioned in the lite ra ture as “nubecullinellen-riffchen” or as “tubiphytes”kamin (chimney), it should be described here briefl y and the differences to crescentiella emphasized. the problematic distinc tion between the former “tubiphytes” morronensis and labes atramentosa is best refl ected in the literature by terms such as “tubiphytes like structure, described as labes atramentosa” (uta & bucur, 2003, pl. 4, fi g. 4). schmid (1996) illustrated material from the stramberk limestones, the type formation of labes atramentosa, as “tubiphytes chimneys” without commenting on the latter taxon. description: the aggregates of this cylindrical to mostly conical shaped organism reach heights of up to 5 mm, with a basal diameter of up to 3 mm. it is characterized by an internal cavity of up to 0–8 mm in diameter surrounded by a micritic “cortex” containing the tube(s) of about 0.09 mm to 0.155 mm in diameter. the transverse to oblique sections of the tubes are arranged mostly between lateral protrusions of the central tube, and are set rather close to it. in contrast to crescentiella, the cortex of labes is made up of dense micritic laminae separated by very thin darker lines, (see schlagintweit et al., 2005, fi g. 70a) also lacking incorporated bioclasts. the tube (or several tubes) coil around an internal cavity similar to isnella described recently from ladinian – carnian reef limestones of several localities in the tethyan realm by senowbari-daryan (2007). as previously mentioned, the “central tube” shows lateral protrusions or spines and in some specimens reaches higher than the surrounding “cortex”, suggesting a biogenic origin (perhaps sponges), in contradiction to isnella, which is assumed to lack a central organism. therefore labes can be interpreted as a real epibiont. a detailed description of late jurassic isnellaand labes-type microfossils and their interpretation is in preparation by schlagintweit. acknowledgement the investigations were carried out within the frame of the research project “se 416/17” supported to b. senowbari-dary an by the deutsche forschungsgemeinschaft. the research of j. matyszkiewicz was fi nanced by the agh statutory grant 11. 11. 140. 560, those of f. schlagintweit by the fwf project p 16812.b06, and those of i.i. bucur and e. săsăran by the project idei.561, cncsis. thanks to r. riding (cardiff) (even if we could not follow some of his remarks) and an anonymous reviewer for critical remarks which helped to improve the manuscript. references abate, b., renda, p. & tramutoli, m. (1988): note illustrative della carta geologica dei monti di termini imerese e delle madonie occidentali (sicilia centro-settentrionale). – mem. soc. geol. ital., 41, 475–505. altiner, d. (1991): microfossil biostratigraphy (mainly foraminifera) of the jurassic – lower cretaceous carbonate succession in northwestern anatolia (turkey). – geol. rom., 27, 167–213. babcock, j.a. (1986): the puzzle of alga-like problematica, or rummaging around in the algal wastebasket. – in: hoffman, a. & nitecki, m.h. (eds.): problematic fossil taxa. oxford university press, new york – clarendon press, oxford, 12–26. barattolo, f. (1991): mesozoic and cenozoic marine benthic calcareous algae with particular regard to mesozoic. – in: riding, r. (ed.): calcareous algae. springer, 505–540. barattolo, f. & pugliese, a. (1987): il mesozoico dell´isola di capri. – academia pontaniana, 8, 1–172. bernier, p. (1984): les formations carbonatées du kimmeridgien et du portlandien dans le jura méridional. stratigraphie, micropaleontologie, sédimentologie. documents des laboratoires de géologie lyon, 92, 1–803. blomeier, d.p.g. & reijmer, j.j.g. (1999): drowning of a lower jurassic carbonate plattform: jbel bou dahar, high atlas, morocco. – facies, 41, 81–110. brachert, th.c. (1986): kontinuierliche und diskontinuierliche sedimentation im süddeutschen oberjura (unteres kimmeridge; ludwag/oberfranken, nördliche frankenalb). – facies, 15, 233–284. brachert, th.c. (1992): sequence stratigraphy and paleo-oceanography of an open-marine mixed carbonate/siliciclastic succession (late jurassic, southern germany). – facies, 27, 191–216. bucur, i.i. (1978): microfaciesurile calcarelor albe din partea nordică a masivului piatra craiului. consideraţii biostratigrafi ce. – dări de seamă ale şedinţelor, institutul de geologie şi geofi zică, 64/4(stratigrafi e)(1976–1977), 89–105. bucur, i.i. & onac, p.b. (2000): new data concerning the age of the mesozoic limestones from scărişoara (bihor mountains). – studia universitatis babeş-bolyai, geologia, 45/2, 13–20. bucur, i.i., senowbari-daryan, b. & abate, b. (1996): remarks on some foraminifera from the upper jurassic (tithonian) reef limestone of madonie mountains (sicily). – boll. soc. paleont. ital., 35/1, 65–80. burza, d.-f. & dragastan, o. (2003): biostratigraphic data concerning the upper jurassic – lower cretaceous limestones from the pojoga area (southern apuseni mts.). – ann. univ. bucuresti, geol. specil. publ., 1, 129–144. carras, n. & georgala, d. (1998): upper jurassic to lower cretaceous carbonate facies of african affi nities in a peri-european area: chalkidiki peninsula, greece. – facies, 38, 153–164. catalano, r., d´argenio, b. & de castro, p. (1974): ripporti tra le facies di piattaforma carbonatica del giurasico e del cretacico delle madonie orientali (sicilia). – boll. soc. natur. napoli, 83, 1–37. chiocchini, m & manchinelli, a. (1979): protopeneroplis trochangulata septfontaine, 1974 (foraminiferida) nel cretaceo inferiore dell´area del gran sasso d´italia (abruzzo). – studi geol. camerti, 5, 17–38. crescenti, u. (1969): biostratigrafi a delle facies mesozoiche dell’appen nino centrale. corelazioni. – geol. rom., 8, 15–40. geologia croaticababa senowbari-daryan et al.: crescentiella, a new name for “tubiphytes” morronensis crescenti, 1969... 211 croneis, c. & toomey, d.f. (1965): gunsight (virgilian) wewokellid sponges and their depositional environment. – j. paleont., 39/1, 1–16. dragastan, o. (1969): “micro-oncolithes” dans le jurassique de la valleé du bicaz (carpates orientales, roumanie). – bull. soc. geól. france, 11/5, 655–659. dragastan, o. (1975): upper jurassic and lower cretaceous microfacies from the bicaz valley bassin (east carpathians). – mém. inst. géol. géophy., 21,1–87. dragastan, o., gielisch, h., richter, d.k., grewer, t., kaziur, th., kube, b. & radusch, ch. (1994): jurassic algae of the perachora-peninsula: biostratigraphical and paleontological implications. – beitr. paläont.wien, 19, 49–81. dragastan, o. & richter, d.k. (2003): calcareous algae and foraminifers from neocomian limestones of methana peninsula, asprovouni mts. (greece) and from south dobrogea (romania). – ann. univ. bucuresti, geol. spec. publ., 1, 57–128. dupraz, ch. & strasser, a. (1999): microbialites and micro-encrusters in shallow coral bioherms (middle to late oxfordian, swiss jura mountains). – facies, 40, 101–130. dupraz, ch. & strasser, a. (2002): nutritional modes in coralmicrobialite reefs (jurassic, oxfordian, switzerland): evolution of trophic structure as a response to environmental change. – palaios, 17/5, 449–471. elias, m.k. (1959): facies of upper carboniferous and artinskian deposits in the sterlitamak-ishimvaevo region of the pre-urals, based on a study of fussulinids. – internat. geol. rev., 1/2, 39–88. eliášová, h. (1986): a new binding microorganism of shallow-water limestones. – vést. ustř. úst. geol., 61, 109–111. flügel, e. (1966): algen aus dem perm der kanischen alpen. – carinthia ii, sonderheft 25, 1–76. flügel, e. (1981): „tubiphyten“ aus dem fränkischen malm. – geol. bl. no-bayern, 31/1–4, 126–142. flügel, e. (2004): microfacies of carbonate rocks, analysis, interpretation and application. – springer, 976 p. flügel, e. & flügel-kahler, e. (1980): algen aus den kalken der trogkofel-schichten der karnischen alpen. – carinthia ii, 36, 113–182. flügel, e. & flügel-kahler, e. (1997): der rote korallenkalk in der hethiter-mauer von bogazköy (anatolien): mikrofazies und herkunft. – geol. bl. no-bayern, 47/1–4, 321–338. flügel, e., riedel, p. & senowbari-daryan, b. (1988): plexoramea cerebriformis mello, ein häufi ges mikrofossil in triadischen flachwasserkalken: alge oder pilz?. – mitt. ges. geol. bergbaustud. österr., 34/35, 263–277. flügel, e. & steiger, t. (1981): an upper jurassic sponge-algal buildup from the northern frankenalb, west germany. – sepm spec. publ., 30, 371–397. fritz, g.k. (1958): schwammstotzen, tuberolithe und schuttbreccien im weißen jura der schwäbischen alb. – arb. geol. paläont. inst. stuttgart, n.f., 13, 1–113. fürsich, f.t., wilmsen, m., seyed-emami, k., schairer, g. & majidifard, m.r. (2003a): platform-basin transport of a middle to late jurassic large-scale carbonate platform system (shotori mountains, tabas area, east-central iran). – facies, 48, 171–198. fürsich, f.t., wilmsen, m., seyed-emami, k. & majidifard, m.r. (2003b): evidence of synsedimentary tectonics in the northern tabas block, east-central iran: the callovian (middle jurassic) sikhor formation. – facies, 48, 151–170. gawlick, h.j. & schlagintweit, f. (2006): berriasian drowning of the plassen carbonate platform at the type-locality and its bearing on the early eoalpine orogenic dynamics in the northern calcareous alps (austria). – inter. j. earth sci. (geol. rundschau), 95, 451–462. gawlick, h.-j., schlagintweit, f., ebli, o. & suzuki, h. (2004): die plassen-formation des krahstein (steirisches salzkammergut, österreich) und ihre unterlagerung: neue daten zur fazies, biostratigraphie und sedimentologie. – zbl. geol. paläont. teil 1 (2003), 3/4, 295–334. gawlick, h.j. & schlagintweit, f. & missoni, s. (2005): die barmsteinkalke der typlokalität nordwestlich hallein (hohes tithonium bis tieferes berriasium; salzburger kalkalpen) – sedimentologie, mikrofazies, stratigraphie und mikropaläontologie: neue aspekte zur interpretation der entwicklungsgeschichte der ober – jura karbonatplattform und der tektonischen interpretation der hallstätter zone von hallein – bad dürrenberg. – n. jb. geol. paläont. abh., 236/3, 351–421. gawlick, h.j., suzuki, h. & schlagintweit, f. (2006): die ober-triasund jura-sedimentgesteine der sarsteinalm und ihre bedeutung für die tektonische gliederung des dachstein-blockes (salzkammergut, nördliche kalkalpen, österreich). – n. jb. geol. paläont. abh, 239/1, 101–160. gwinner, m.p. (1971): carbonate rocks of the upper jurassic in swgermany. – in: müller, g. (ed): sedimentology of parts of central europe. guidebook 8th int. sediment. congr., 193–207. helm, c. (2005): riffe und fazielle entwicklung der fl origemma-bank (korallenoolith, oxfordium) im süntel und östlichen wesergebirge (nw-deutschland). – geol. beitr. hannover, 7, 3–339. helm, c & schülke, i. (2001): „tubiphytes“ morronensis aus der malm-gruppe (korallenoolith, niedersächsisches becken) des ith (nordwest-deutschland). – ber. naturhist. ges. hannover, 143, 99– 107. henssel, k., schmid, d.u. & leinfelder, r.r. (2002): computergestützte 3d-rekonstruktionen in der paläontologie anhand von serienschnitten. – mathematische geologie, 6, 131–142. homann, w. (1972): unterund tief-mittelpermische kalkalgen aus den rattendorfer schichten, dem trogkofel-kalk und dem treßdorfer kalk der karnischen alpen (österreich). – senckenbergiana lethaea, 53/3–4, 135–313. hüssner, h. (1985): jurassische karbonate des westlichen hohen atlas (marokko): mikrofaziesanalyse und plattentektonischer rahmen. – facies, 12, 141–218. johnson, j.h. (1963): pennsylvanian and permian algae. – colorado schoool mines, quart., 58/3, 1–211. keupp, h., koch, r. & leinfelder, r. (1990): steuerungsprozesse der entwicklung von oberjura-spongiolithen süddeutschlands: kenntnisstand, probleme und perspektiven. – facies, 23, 141–174. koch, r., senowbari-daryan, b. & strauss, h. (1994): the late jurassic ´massenkalk fazies´ of southern germany. calcareous sand piles rather than organic reefs. – facies, 31, 179–208. kochansky-devidé, v. (1970): permische mikrofossilien der westka rawanken. – geologija, 13, 174–256. kott, r. (1989): fazies und geochemie des treuchtliner marmors (unterund mittel-kimmeridge, südliche frankenalb). – berliner geowiss. abh., a, 111, 1–115. krajewski, m. (2000): lithology and morphology of upper jurassic carbonate buildups in the będkowska valley, kraków region, southern poland. – ann. soc. geol. polon., 70, 151–163. geologia croatica geologia croatica 61/2–3 212 krajewski, m. (2001): upper jurassic chalky limestones in the zakrzówek horst, kraków, kraków-wieluń upland (south poland). – ann. soc. geol. polon., 71, 43–51. kraus, o. & ott, e. (1968): eine ladinische riff-fauna im dobratsch gipfelkalk (kärnten, österreich) und bemerkungen zum faziesvergleich von nordalpen und drauzug. – mitt. bayer. staatssamml. paläont. hist. geol., 8, 263–290. kuss, j. (1990): middle jurassic calcareous algae from the circumarabian area. – facies, 22, 59–86. lang, b. (1989): die schwamm-biohermfazies der nördlichen frankenalb (urspring; oxford, malm): mikrofazies, palökologie, paläontologie. – facies, 20, 199–274. lehrmann, d.j., wei, j. & enos, p. (1998): controls of facies architecture of at large triassic carbonate platform: the great bank of guizhou, nanpanjiang basin, south china. – j. sediment research, 68/2, 311–326. leinfelder, r.r. (1992): a modern-type kimmeridgian reef (ota limestone, portugal): implications for jurassic reef models. – facies, 26, 11–34. leinfelder, r.r., nose, m., schmid, d.u. & werner, w. (1993): microbial crusts of the late jurassic: composition, palaeoecological signifi cance and importance in reef construction. – facies, 29, 195–230. leinfelder, r.r., werner, w., nose, m., schmid, d.u., kra ut ter, m., laternser, r., takacs, m. & hartmann, d. (1996): paleocology, growth parameters and dynamics of coral, sponge and microbiolite reefs from the late jurassic. – in: reit ner, j., neuweiler, f. & gunkel, f. (eds.): global and regional controls on biogenic sedimentation. i. reef evolution. research reports. göttinger arb. geol. paläont., sb2, 227–248. le mone, d.v. (1995): the role of shamovella (“tubiphytes”) in bioherms. – in: graber, r. a. & lindsay, r.f. (eds.): wolfcampian-leonardian shelf-margin facies of the sierra diablo. seismic scale models for subsurface exploration. annual field guidebook. west texas geol. soc. publ., 95–97, 135–144. luperto sinni, e. & masse, j.p. (1994): precisazioni micropaleonotologiche sulle formazioni di piattaforma carbonatica del giruassico superiore e del cretaceo basale del massiccio del gargano (italia meridionale) e implicazioni stratigrafi che. – paleopelagos, 4, 243–266. maslov, v.p. (1956): fossil calcareous algae of the urss. – trudy geologicheskii nauk institut urss, moskow, 160, 301 p. [in russian]. matyszkiewicz, j. (1989): sedimentation and diagenesis of the upper oxfordian limestones in piekary near kraków. – ann. soc. geol. polon., 59, 201–230. matyszkiewicz, j. (1997a): microfacies, sedimentation and some aspects of diagenesis of upper jurassic sediments from the elevated part of the northern peri-tethyan shelf: a comparative study on the lochen area (schwäbische alb) and the cracow area (cracowwieluń upland, poland). – berl. geowiss. abh., e21, 1–111. matyszkiewicz, j. (1997b): stromatactis cavities and stromatactislike cavities in the upper jurassic carbonate buildups at młynka and zabierzów (oxfordian, southern poland). – ann. soc. geol. polon., 67, 45–55. matyszkiewicz, j. (1999): sea-bottom relief versus differential compaction in ancient platform carbonates: a critical reassessment of an example from upper jurassic of the cracow-wieluń upland. – ann. soc. geol. polon., 69, 63–79. matyszkiewicz, j. & felisiak, i. (1992): microfacies and diagenesis of an upper oxfordian carbonate buildup in mydlniki (cracow area, southern poland). – facies, 27, 179–190. matyszkiewicz, j. & krajewski, m. (1996): lithology and sedimentation of upper jurassic massive limestones near bolechowice, kraków-wieluń upland, south poland. – ann. soc. geol. polon., 66, 285–301. matyszkiewicz, j., krajewski, m. & kędzierski, j. (2006): origin and evolution of an upper jurassic complex of carbonate buildups from zegarowe rocks (kraków-wieluń upland, poland). – facies, 52, 249–263. matyszkiewicz, j., krajewski, m., tyc, a., król, k., kędzierski, j., jędrys, j. & świąder, j. (2004): facial development of the upper jurassic complex of the zegarowe rocks near smoleń (kraków-wieluń upland; southern poland) [in polish with english summary]. – in: partyka, j. (ed): zróżnicowanie i pr zemiany środowiska przyrodniczo-kulturowego wyżyny krakowskoczęstochowskiej. ojcowski park narodowy, spec. publ. 1, 35–42. matyszkiewicz, j. & słomka, t. (1994): organodetrital conglomerates with ooids in the cieszyn limestone (tithonian – beriasian) of the polish flysch carpathians and their paleographic signifi cance. – ann. soc. geol. polon., 63, 211–248. mello, j. (1977): plexoramea cerebriformis n. gen., n. sp. and some other microproblematics and microfossils from triassic limestones of the west carpathians. – zapadne karpaty, ser. paleont., 2–3, 189–202. meyer, r.k.f. (1975): mikrofazielle untersuchungen in schwammbiohermen und -biostromen des malm epsilon (ober-kimmeridge) und obersten malm-delta der frankenalb. – geol. bl. no-bayern, 25, 149–177. meyer, r.k.f. (1977): mikrofazies im übergangsbereich von der schwam mfazies zur korallen-spongiomorphiden-fazies im malm (kimmeridge – tithon) von regensbrug bei kelheim. – geol. jb., a37, 33–69. meyer, r.k.r. & schmidt-kahler, h. (1984): erdgeschichte sichtbar gemacht: ein geologischer führer durch die altmühltal. – bayer. geol. landesamt, münchen, 260 p. mišík, m. (1979): jurassic and cretaceous algae (dasycladales excepted) from the west carpathians. – bull. cent. rech. explor. – prod. elf-aquitaine, 3/2, 705–712. mišík, m. & sykora, m. (1980): jura der silica-einheit, rekonstruiert aus geröllen, und oberkretazische süsswasserkalke des gemerikums. – geol. zbornik – geol. carpatica, 31/3, 239–261. moussavian, e. (1992): on cretaceous bioconstructions: composition and evolutionary trends of crust-building associations. – facies, 26, 117–144. neuweiler, f., mehdi, m. & wilmsen, m. (2001): facies of liassic sponge mounds, central high atlas, morocco. – facies, 44, 243–264. olóriz, f., reolid, m. & rodriguez-tovar, f.j. (2003): a late jurassic carbonate ramp colonized by sponges and benthic microbial communities (external prebetic, southern spain). – palaios, 18/6, 528–545. payne, j.l., lehrmann, d., christensen, s., wie, j. & knoll, a.h. (2006): environmental and biological controls on the initiation and growth of a middle triassic (anisian) reef complex on the great bank of guizhou, guizhou province, china. – palaios, 21, 325–343. pomoni-papaioannou, f., flügel, e. & koch, r. (1989): depositional environments and diagenesis of upper jurassic subsurface spongeand tubiphytes-reef limestones: altensteig 1 well, western molasse basin, southern germany. – facies, 21, 263–284. pratt, b.r. (1995): the origin, biota and evolution of deep-water mudmounds. – international association of sedimentologists, spec. publ., 23, blackwell science 49–123. geologia croaticababa senowbari-daryan et al.: crescentiella, a new name for “tubiphytes” morronensis crescenti, 1969... 213 rauser-chernoussova, d.m. (1950): facies of upper carboniferous and artinskian deposits in the sterlitamak-ishimbaevo region of the pre-urals, base on a study of fusulinids. – trudy inst. geol. nauk akad. nauk sssr, trans. 119, 43, 1–108 [in russian]. radoičić, r. (2005): new dasycladales and microbiota from the lowermost valanginian of the mirdita zone. – ann. géol. pénins. balk., 66 (2004–2005), 27–53. ramalho, m. (1971): contribution à l´étude micropaléongologique et stratigraphique du jurassique supérieur et du crétacé inférieur des environs de lisbone (portugal). – serv. geol. portugal, mem. 19, 1–212. richter, d.k., dragastan, o., kube, b., beck, t. & zuhl, h. (1999): fazies und biostratigraphie des fi nalen stadiums der obertriadischen karbonatplattform von hydra (kap kastello/westrand des pelagonikums/ griechenland). – in: richter, d.k. & wurth, g. (eds.): beiträge zur sedimentologie von griechenland. bochumer geol. geotech. arbeiten, 53, 127–147. riding, r. (1993): shamovella obscura: the correct name for tubiphytes obscurus (fossil). – taxon, 42, 71–73. riding, r. & barkham, s. (1999): temperate water shamovella from the lower permian of west timor, indonesia. – alcheringa, 23, 21–29. riding, r. & guo, l. (1992): affi nity of tubiphytes.palaeontology, 35&1, 37-49. rigby, j.k. (1958): two new upper paleozoic hydrozoans. – j. paleont., 32, 583–586. santantonio, m., gullzzo, f. & gill, g. (1996): anatomy and paleobathymetry of a jurassic pelagic carbonate platform/basin system. rossa mts, central apennines (italy). geological implications. – palaeopelagos, 6, 123–169. săsăran, e., bucur, i.i. & prica, i. (2001): microfacies and microfossils in the upper jurassic limestones from cheile turenilor. – studia universitatis babeş-bolyai, geologia, 46/2, 35–52. săsăran, e., hosu, a., spălnăcan, r., & bucur, i.i. (2000): microfacies, microfossils and sedimentary evolution of the sănduleşti limestone formation in cheile turzii (apuseni mountains, romania). – acta palaeont. romaniae, 2 (1999), 453–462. scheibner, ch. & reijmer, j.j.g. (1999): facies patterns within a lower jurassic upper slope to inner platform transect (jbel bou dahar, morocco). – facies, 41, 55–80. scherze, e. & höfling, r. (2002): growth habits of encrusting organisms in late jurassic oncoids of eastern spain (prov. valencia). – in: bucur, i.i. & fillipescu, s. (eds.): research advances in calcareous algae and microbial carbonates. university press, cluj, 191-200. schlagintweit, f. (2004): iberopora bodeuri granier & berthou 2002 (incertae sedis) from the plassen formation (kimmeridgianberriasian) of the tethyan realm. – geol. croat., 57/1, 1–13. schlagintweit, f. & ebli, o. (1999): new results on microfacies, biostratigraphy and sedimentology of late jurassic – early cretaceous platform carbonates of the northern calcareous alps. – abh. geol. b.-a., 56/2, 379–418. schlagintweit, f. & gawlick, h.-j. (2003): mikrobolithe und mikroinkrustierer aus der plassen-formation (kimmeridgium-berriasium) der nördlichen kalklapen. – in: weidinger, j.j., lobitzer, h. & spitzbart, i. (eds.): beiträge zur geologie des salzkammerguts. gemundner geo-studien, 2, 107–114. schlagintweit, f. & gawlick, h.-j., ebli, o., rünstler, h. & suzuki, h. (2003a): die plassen-formation (kimmeridgium) des krahstein (steirisches salzkammergut, österreich) und deren unterlagerungen: neue daten zur fazies, biostratigraphie und sedimentologie. – in: weidinger, j.j., lobitzer, h. & spitzbart, i. (eds.): beiträge zur geologie des salzkammerguts. gemundner geo-studien, 2, 87–96. schlagintweit, f., gawlick, h.-j. & lein, r. (2003b): die plassen-formation der typlokalität (salzkammergut, österreich) – neue daten zu fazies, sedimentologie und stratigraphie. – mitt. ges. geol. bergbaustud. österr., 46, 1–34. schlagintweit, f., gawlick, h.-j. & lein, r. (2005): mikropaläontologie und biostratigraphie der plassen-karbonatplattform der typlokalität (ober-jura bis unter-kreide, salzkammergut, österreich). – journal of alpine geology (mitt. ges. geol. bergbaustud. österreich), 47, 11–102. schmid, d.u. (1995): „tubiphytes“ morronensis – eine fakultativ inkrustierende foraminifere mit endosymbiotischen algen. – profi l, 8, 305–317. schmid, d.u. (1996): marine mikrobiolithe und mikroinkrustierer aus dem oberjura. – profi l, 9, 101–251. schmid, d. & henssel, k. (2001): die rätselhaften tubiphyten der treuchtinger marmors. – mitt. bayer. paläont. staatssamml., jahresbr. 2000, 45–54. schmidt-kahler, h. (1962): stratigraphische und tektonische untersuchungen im malm des nordöstlichen ries-rahmens. – erlanger geol. abh., 44, 1–51. senowbari-daryan, b. (2007): isnella misiki nov. gen., nov. sp., kein „tubiphytes“, aber eine mögliche foraminifere, wurmröhre oder cyanophycee aus den ladinisch-karnischen riffkalken der tethys. – j. alpine geol. (mitt. ges. geol. bergbaustud. österr.), 48, 45–56. senowbari-daryan, b., bucur, i.i. & abate, b. (1994): upper jurassic calcareous algae from the madonie mountains, sicily. – beitr. paläont. wien, 19, 227–259. senowbari-daryan, b., bucur, i.i., schlagintweit, f., săsăran, e. & matyszhkiewicz, j. (2007): crescentina, new generic name for „tubiphytes“ morronensis crescenti, 1969. – in: grgasović, t. & vlahović, i. (eds.): 9th international symposium on fossil algae, field-trip guidebook and abstracts. croatian geological survey, zagreb, 251-252. senowbari-daryan, b. & flügel, e. (1993): tubiphytes maslov, an enigmatic fossil: classifi cation, fossil record and signifi cance through time. part i: discussion of late paleozoic material. – in: barattolo, f., de castro, p. & parente, m. (eds.): studies on fossil benthic algae. boll. soc. paleont. ital., special vol. 1, 253–382. senowbari-daryan, b. velledits, f. (2007): axopora aggtelekensis schloz 1972, originally described as hydrozoa, is attributed to the new genus anisophytes (canophyta?). – riv. ital. paleont. stratigr., 113/3, 357–368. steiger, t. & jansa, l.f. (1984): jurassic limestones of the seaward edge of the mazagan carbonate platform, northwest african continental margin, morroco. – intitial rep. deep sea drilling proj, 79, 449–491. uta, a. & bucur, i.i. (2003): microbial structures and microencrusters in the upper jurassic – lower cretaceous deposits from builavanturarita massif (south carpathians). – studia univ. babes bolyai, geol., 48/2, 3–14. vachard, d., hauser, m., martini, r. & zaninetti, l., matter, a. & peters, t. (2001): new algae and problematica of algal affi nity from the permian of the aseelah unit of the batain plain (east oman). – geobios, 34/4, 375–404. geologia croatica geologia croatica 61/2–3 214 vennin, e., vachard, d. & proust, j.-n. (1997): taphonomie et synécologie du genre tubiphytes dans les bioconstructions detratau et de nizhni-irginsk (permien inférieur de l´oural, russie). – géobios, 30/5, 635–649. volk, h., koch, r. & franz, m. (2001): fazieskartierung in „massenkalken“ des weißjura delta 1 bis zeta 1 (ki2.2 bis ki4). ein beispiel aus dem oberen donautal (westliche schwäbische alb). – geol. bl. no-bayern, 51/3–4, 274–332. wagenplast, p. (1972): ökologische untersuchungen der fauna aus bankund schwammfazies des weißen jura der schwäbischen alb. – arb. geol. paläont. inst. stuttgart, n.f., 67, 1–99. wang, s., fan, j. & rigby, j.k. (1994): archaeolithoporella and tubiphytes: affi nities and paleoecology in permian reefs of south china. – science in china, ser. b, 37/6, 723–743. weidlich, o. (2001): middle and late permian reefs – distribution patterns and reservoir potential. – sepm spec. publ., 72, 339–390. wu, y.sh. (1991): organisms and communities of permian reef of xiangbo, china. – intern. acad. public., beijing, 192 p. manuscript received december 19, 2007 revised manuscript accepted june 16, 2008 new stratigraphic and palaeogeographic results from the palaeozoic and early mesozoic of the middle pontides (northern turkey) in the azdavay, devrekani, küre and inebolu areas: implications for the carboniferous early cretaceous geodynamic evolution and some related remarks to the karakaya oceanic rift basin heinz w. kozur 1, mustafa aydin2, osman demir 2, huseyin yakar 3, m. cemal göncüoğ lu4 and ferudun kuru 3 g eol. cr oat. 53/2 209 268 3 figs. 1 tab. 15 pls. zagreb 2000 key words: pelagic upper carboniferous and permian, middle triassic oceanic crust, upper triassic to middle jurassic accretionary complex, hallstatt limestone, t o r l e s s i a, microfauna, northern turkey, middle pontides, paphlagonian ocean, küre ocean and karakaya oceanic rift basin. 1 rézsü u. 83, budapest, hungary. 2 türkiye petrolleri a.o., exploration group, mustafa kemal mahallesi, 2. cadde no. 86, 06502 esentepe-ankara, turkey. 3 türkiye petrolleri a.o., research center, mustafa kemal mahallesi, 2. cadde no. 86, 06502 esentepe-ankara, turkey. 4 department of geological engineering, middle east technical university, inönü bulvari, 06531 ankara, turkey. abstract the küre complex of the middle pontides, northern turkey, is not a remnant of the palaeotethys but consists of three different units with differing geological history, the küre ridge unit, the küre ocean unit and the çalça unit. the küre ridge unit consists of the serveçay group, a pre-permian, low-grade metamorphic variscan oceanic sequence, and the sırçalık group, a lower and middle triassic shallow-water sequence of north alpine facies and event succession which disconformably overlies the serveçay group. following a hiatus, the sırçalık group is overlain by marginal parts of the akgöl group with olistoliths of local origin which were derived mainly from the sırçalık group. the küre ocean unit consists mostly of the akgöl group (siliciclastic turbidites and olistostromes of the karad ağtepe formation, which is a middle carnian to middle jurassic accretionary complex from the southern, active margin of the küre ocean, and mainly middle jurassic molasse type shallow-water sandstones, siltstones and shales of an unnamed formation) and of thick oceanic basalts (i . psinler basalt). tectonic slices of middle triassic to lower carnian ophiolites and basalts are also present. the karad ağtepe formation contains numerous middle triassic exotic olistoliths and blocks of shallow-water and predominantly slope and basinal limestones, ocean-floor deep-sea sediments (shales and radiolarites), basalts and small clasts of ophiolites or ophiolitic detritus. the çalça unit consists of deposits from the northern, passive margin of the küre ocean with many pelsonian to upper norian hallstatt limestones and rhaetian -lower jurassic (?middle jurassic) deep-water shales and marls. all three units are overlain following a period of non deposition by the upper jurassic bürnük formation (red conglomerate, sandstone) and i . naltı formation (shallow-water platform carbonates). the küre ridge unit was split away from the variscan sakarya continent by the opening of the karakaya oceanic rift basin during latest permian (dorashamian) and became a continental splinter between the karakaya oceanic rift basin and the küre ocean (opened during the late scythian). southward subduction began in the küre ocean during the middle carnian (beginning of the karadağtepe siliciclastic turbidites), whereas at the northern passive margin the deposition of hallstatt limestones continued until the latest norian. the deposition of siliciclastic turbidites and olistostromes (diskaya unit) began in the entire karakaya oceanic rift basin during the middle carnian, and ocean basin deposits (radiolarites, pelagic limestones) and slope deposits form the passive margin (e.g., hallstatt limestones) are no more present in the karakaya oceanic rift basin indicating that this basin was very narrow (only a few hundreds of kilometres). during the late norian, the karakaya oceanic rift basin closed, whereas subduction at the southern (active margin) of the küre ocean continued. at the northern margin of the (upper triassic?) jurassic -lower cretaceous b e y k oz-ç ağlayan turbidite basin (north of the küre complex) the accretionary complex of an older ocean, the late palaeozoic paphlagonian ocean, was exposed that yielded clasts in the beykoz -ç ağl ayan turbidite basin. among these clasts carboniferous to middle permian (capitanian) pelagic rocks (pelagic limestones, radiolarites) could be dated. a middle to late permian southward-directed subduction is assumed for the paphlagonian ocean. its closure occurred either at the end of the permian or during the scythian. 210 geologia croatica 53/2 1. introduction and general geological setting of the middle pontides and immediately adjacent areas the küre complex of the middle pontides south of inebolu, northern turkey (investigated area, fig. 1) plays an important role in the palaeogeographic reconstructions of the late palaeozoic and early mesozoic of turkey and adjacent areas. two conflicting palaeogeographic models were developed by the şe n g ö r school (e.g., şengör & yilmaz, 1981; şe n g ö r , 1984, 1985; şengör et al., 1984; genç & yilmaz, 1995; yilmaz et al., 1997) on one side, and okay and co-authors (e.g., okay & mostler, 1994; okay et al., 1996) as well as robertson and coauthors (e.g., pickett et al., 1995; ustaömer & robertson, 1995, 1997, 1999; pickett & robertson, 1996) on the other. the first model regards the küre complex as a remnant of the southwards subducting late palaeozoic triassic palaeotethys, and the karakaya oceanic rift basin as a latest permian triassic back-arc basin that was closed during the upper triassic by southward subduction. the second model regards the karakaya basin as the large, devonian to triassic palaeotethyan ocean and the küre basin as a short-lasting, small, oceanic basin which opened as a back-arc basin by the northward subduction of the karakaya oceanic lithosphere. some authors considered the karakaya oceanic rift basin as a triassic ocean or rift basin (as in the first model) without regard to the age of the küre complex (okay, 1991; altiner & koçyigit, 1993), whereas yi . ği . t b aş et al. (1999) regarded the küre complex as the remnants of a persistent pa l a e o t e t h y a n ocean (as in the first model) without regarding the karakaya complex. these papers also support the first model. a third model regarding the relation of the karakaya oceanic rift basin and küre ocean was presented by okay & tüysüz (1999) and okay (2000). according to these authors both oceanic basins represent the same large palaeotethyan ocean and the present separation is a later feature. the hp/lt metamorphic nilüfer unit of the karakaya complex was regarded as an oceanic plateau despite the fact that the lower half contains shallow-water (?algal) limestones with mafic metatuffs and also in the upper half the water-depth was (according to the fauna) probably not below 100-200 m. the view of robertson and co-authors of a carboniferous-triassic age of the karakaya oceanic rift basin is for the palaeozoic (pre-dorashamian) part based only on an assumption which is in conflict with the fact that in the post-bashkirian pre-latest dzhulfian interval only shallow-water limestones are known and dated (kozur & kaya, 1994; leven & okay, 1996; kozur, unpubl. data). these permian shallowwater rocks were regarded by robertson and co-authors as sea-mount deposits. however, in this case the seamounts of this age interval must be more than 1,000 km long and had filled the entire ocean because basinal and even slope sediments are unknown in this time interval. moreover, these seamounts had to be persistent (throughout most of the pennsylvanian, the entire early and middle permian and the lower part of the late permian) and covered by a facially stable carbonate platform. contemporaneous mafic volcanics and volcaniclastics are not known from the moscovian to middle dzhulfian interval. all these features are in total contrast with well-documented permian seamounts in panthalassa studied by one of the authors (h.w. kozur) and also different from palaeotethyan seamounts (kozur & şenel, 1999). the assumption of a large carboniferous p e r m i a n (and triassic) karakaya ocean by okay and co-authors was based on the fact that the youngest olistoliths of the largely broken variscan basement are cherty limestones of early bashkirian age (okay & mostler, 1994; kozur, 1999), whereas red radiolarites of the dorashamian to middle triassic çal unit (okay et al., 1991) were erroneously dated as sakmarian-artinskian in one locality (okay & mostler, 1994). re-examination of this locality se of çan in the biga peninsula, northwestern turkey (for precise locality data see okay & mostler, 1994) by kozur (1999) yielded a rich late dorashamian radiolarian fauna in all exposed radiolarites confirming the former conodontbased dating of the opening of the karakaya oceanic rift basin by kozur & kaya (1994). the assumed late permian mafic volcanics, mainly tuffs (okay & mostler, 1994), were dated as post-latest scythian because they contain inclusions of conodont-bearing latest scythian limestones (kozur, 1999). the formerly assumed latest permian opening of the karakaya oceanic rift basin (first model, see above) during the dorashamian stage could be confirmed palaeontologically by kozur & kaya (1994), kozur (1999) and kozur et al. (1999). pelagic uppermost dzhulfian and dorashamian limestone olistoliths from the upper diskaya unit (kaya et al., 1986; junior synonym: hodul unit, okay et al., 1991) and late dorashamian red radiolarites of the çal unit are the oldest pelagic rocks of the karakaya complex. the oldest dated mafic volcanics have a scythian age (table 1). the missing geochemical signals for subduction related mafic rocks in the nilüfer unit of the karakaya complex (within plate basalts, ustaömer & r o b e r tson, 1999) is no evidence for a large late palaeozoictriassic palaeotethyan karakaya ocean, as assumed by ustaömer & robertson (1995, 1997, 1999), pickett et al. (1995), okay et al. (1996) and pickett & robertson (1996), but indicates early rifting in a shallow-water carbonate platform. the karakaya oceanic rift basin was not even a moderately wide back-arc basin, such as the küre ocean, but a very narrow oceanic rift basin which probably never extended beyond the width of the red sea. this is also indicated by the fact that from the middle carnian beginning of the siliciclastic turbidite-olistostrome deposition (diskaya unit) no turbidite-free pelagic sedimentation continued in the karakaya oceanic rift basin (neither an upper triassic passive margin sequence with hallstatt limestones nor upper triassic ribbon cherts, shales and pelagic limestones of an ocean floor sequence are known). as mentioned above, the recent biostratigraphic data have shown that the karakaya oceanic rift basin existed between the latest permian (dorashamian) and upper triassic in agreement with the first model (view of the şengör school). the southward subduction of the küre ocean and the time of the closure of this ocean is also in agreement with the first model. however, the küre ocean is not the persistent large palaeotethys, but a short-lasting latest scythian to middle jurassic back-arc basin as assumed in the second model. therefore, both former models are partially incorrect. the latest permian late triassic karakaya oceanic rift basin is not the back-arc-basin of the late palaeoz o ic middle jurassic palaeotethyan küre basin, because the küre basin is a latest scythian to middle jurassic back-arc basin. on the other hand, the küre basin is not the back-arc basin of a devonian triassic palaeotethyan karakaya ocean because the karakaya oceanic rift basin is also a very short lasting basin (dorashamian to middle norian). none of the two oceans correspond to the lower devonian to carnian (upper triassic) palaeotethys, the remnants of which (both oceanic crust, morb and oib, and well-dated sediments) were 211kozur, aydin, demir, yakar, göncüoğlu & kuru: new stratigraphic and palaeogeographic results... fig. 1 geological map of the investigated area. modified after aydin et al. (1995). legend: 1-6) most important sampled localities. 1 outcrop in the middle to upper carnian turbiditic-olistostromal part of the akgöl group at the küre -inebolu road. 2 outcrop in the zerveçay creek valley south of gemiçiler (evrenye) at the gemiçiler h a r a m i d ağ road. serveçay group overlain by tectonically reduced scythian (basal conglomerate sandstone -werfen marls and limestones) and anisian “gutenstein” limestone. 3 outcrops along the road between the villages of aha and sırçalık. scythian with well exposed werfen beds (partly assigned to the ladinian on the basis of “daonella”, which is a scythian eumorphotis) overlain by hypersaline beds with “rauhwacke”, “gutenstein” limestone and steinalm dolomite, both anisian shallow-water platform carbonates of north alpine character. some outcrops of the akgöl group, partly stratigraphically overlying the sırçalık formation, partly tectonic slices of the karadağtepe formation. 4 outcrop at kircalla village e of azdavay. beykoz formation with an olistostrome that contains shallow-water and pelagic permian limestones blocks; the largest one is an almost matrix-free permian debris flow. 5 roadcut at the kastamonu-inebolu road, about 3 km west of devrekani, olistostrome with many olistoliths, consisting mainly of anisian pelagic, subordinately also shallow-water and slope limestones. about 300 m north of this outcrop, the blocks of anisian, often ammonoid-bearing pelagic limestones within akgöl debris flows are several metres in diameter. 6 large outcrops of hallstatt limestones in the çalça unit south of çalça village. 212 geologia croatica 53/2 recently found in the composite tavas nappes (lycian nappes, kozur & şenel, 1999; göncüoğlu et al., 2000; kozur et al., in press c). the third model (okay, 2000), which regarded the küre basin and the karakaya oceanic rift basin as parts of a single ocean, the huge carboniferous to middle jurassic palaeotethys, is also incorrect. it can be easily proven that the assumed northward subduction of this united karakaya-küre ocean is a wrong assumption not supported by any field data. the northern (laurasian) margin of the assumed unified ka r a k a ya küre ocean was a passive margin with condensed middle anisian to late norian hallstatt limestones without any terrigenous input, and rhaetian liassic shales and marls. therefore, the deposition of hallstatt limestones continued at the northern margin of the assumed karakayaküre ocean after the beginning of siliciclastic turbidites and olistostromes at its active southern margin and even after the closure of the karakaya rift basin at the end of the middle norian or within the late norian. moreover, uniting two early mesozoic oceanic basins do not create a carboniferous to middle jurassic ocean. the age of the küre complex was based on assumptions in all previous models. either the units (metamorphic and non-metamorphic), like the non-metamorphic akgöl group have not yielded stratigraphically important fossils or their age was misinterpreted. thus, different or very imprecise ages were given even for the non-metamorphic units. for instance, the age of the akgöl group is said to be pre-middle jurassic (okay 2000), early triassic to early-middle jurassic (u s t aömer & robertson, 1997), permian to middle jurassic (yi . ği . t b aş et al., 1999), carboniferous to liassic (yilmaz & şengör, 1985; aydin et al., 1986; önder et al., 1987; yilmaz et al., 1997) or upper palaeozoic to early mesozoic (ustaömer & table 1 units of the karakaya oceanic complex 213kozur, aydin, demir, yakar, göncüoğlu & kuru: new stratigraphic and palaeogeographic results... robertson, 1999). according to ustaömer & robertson (1999) “southward subduction of the küre oceanic lithosphere is inferred to have started in early triassic time, the oldest well established age of the küre marginal basin”. lower triassic fossils are unknown from the oceanic akgöl group and the subduction began in the middle carnian (see below). as shown in this paper, the oldest pelagic limestones known from olistoliths in the akgöl group (and from the entire küre complex), are of earliest middle triassic age. thus, the opening of the küre ocean began either in the earliest middle triassic or during the latest scythian. thus, the “well established age” of the beginning subduction was even before the küre ocean opened. the age of the metamorphic units of the küre complex is much more uncertain than the above mentioned different age ranges for the fossiliferous oceanic akgöl group. it is obvious that exact stratigraphic dating of the oceanic akgöl group and the continental units of the küre complex is necessary before the former tectonic models can be evaluated and a new model can be established to explain the geological evolution of this complex and the adjacent oceanic units where all previous hypotheses have failed. therefore, the main topic of the present paper is the dating of the küre complex and adjacent units. the basis of this work was the careful mapping and detailed lithostratigraphic subdivision of the units by aydin et al. (1995). in the terminology of that paper, the küre complex consists of the bekirli group (serveçay group of the present paper), the sırçalık “formation” and the akgöl “formation” (the formations are in reality groups subdivided below into different formations and units). many important biostratigraphic results were obtained both from the matrix and from olistoliths in different turbidite-olistostrome units which allow to make new palaeogeographic reconstructions. the upper age limit of the metamorphic units within the küre complex could be determined by the dating of transgressively overlying units. these results did not confirm the three afore-mentioned models of the geological evolution of the küre complex and adjacent oceanic and continental units. 2. tectonostratigraphic units of the küre complex, their lithologies and ages the küre complex includes three main tectonostratigraphic units: the küre ridge unit, the küre ocean unit and the çalca unit, and a tectonic inlayer, the devrekani metamorphics. the names of the lithostratigraphic units, except for the bekirli group, are overtaken from aydin et al. (1995). some modifications are necessary in the assumed mutual relations and above all in the assumed ages. the ages are partly also discussed under biostratigraphic results. 2.1. devrekani metamorphics the devrekani metamorphics (ebrek metamorphics of yilmaz, 1981) occur as a tectonic inlayer within the küre complex, and consist of gneisses, amphibolites, calc-schists and marbles. the rock-units are too highly metamorphosed (amphibolite facies) for palaeontological or palynological investigations. only relative age dating is possible. however, gneisses taken 6 km east of devrekani village, were dated as 311 ± 6 . 2 my (aydin et al., 1995) indicating a middle carboniferous age and giving an upper age limit for these metamorphics. we regard the devrekani metamorphics as variscan metamorphics. a precambrian age of the devrekani metamorphics assumed or tentatively assumed by several authors (e.g. ustaömer & robertson, 1995) is not probable for facies reasons (mainly pelagic platy limestones with shale intercalations and olistoliths and blocks of shallow-water limestones). but older precambrian units within the variscan devrekani metamorphics may be present. this question can only be solved by further radiometric dating. 2.2. küre ridge unit the metamorphosed variscan basement of the serveçay group and the overlying unmetamorphosed but deformed sırçalık group (and the partly present cover of marginal parts of the akgöl group) built up the küre ridge unit of the küre complex (fig. 2). the küre ridge unit was during the triassic the common shelf of the küre ocean and the karakaya oceanic rift basin (southern shelf of the küre ocean and northern shelf of the karakaya oceanic rift basin). as direct biostratigraphic dating is only possible for the sırçalık group and the upper age limit of the serveçay group metamorphics depends on exact age determination of the sırçalık group and its structural position to the serveçay group, the younger sırçalık group is firstly discussed. 2.2.1. sırçalık group the sırçalık group (in the rank of sırçalık formation) was regarded as a sedimentary intercalation within the upper part of the metamorphics of the bekirli group (serveçay group in the present paper, see below) by aydin et al. (1995). however, the intercalation of middle triassic shallow-water platform carbonates within the uppermost “bekirli metamorphics” (serveçay group) could not be confirmed in the zerveçay creek valley section south of gemiçiler (evrenye) at the gemiçiler haramidağ road (locality 2 in fig. 1), where this “intercalation” of the sırçalık “formation” within the upper serveçay group with “gradual transition” to the serveçay group was established. the deformed, but unmetamorphosed shallow-water carbonates, without any siliciclastic input are there tectonically sliced with low-grade metamorphic siliciclastic sediments of the serveçay group. carbonate intercalations within the serveçay group always occur as strongly recrystallized 214 geologia croatica 53/2 marbles, so strongly metamorphosed that no determinable fossils are preserved. in the deformed but unmetamorphic carbonates of the sırçalık group not only microfossils (foraminifers, s p i r o r b i s) but also determinable macrofossils (bivalves) are present. the discovery of tectonically reduced scythian rocks beneath the middle triassic shallow-water limestones in zerveçay creek valley section was important as they stratigraphically, but disconformably overlie the serveçay group and begin with a quartz conglomerate derived from the metamorphic rocks of the serveçay group. this basal conglomerate also contains scarce fig. 2 lithological successions in the three units of the küre complex. z >< w ----.j 0.... t:: 2 :z: = 0 :z: < u u.i u 0 w lou ~ c::: := :=:j ::.::: i ~ if) " ~ g i i i i i , i i i : i i 1.1 :;:; .., :?: , , r,.. : ····i~··············· ................... ................. . : :6: r:: :6: r::· .............. ........... .. • ii ii ii iiii i i :ji r:;;;· " ... c ti ~ , .., ~ i ·8 = '" ::jissvdnr c ~ , , .!i .~ .., .., :j: e ~ :~ "it (j <! 1:;';1 ::ji s s\fi ill nlilllljd3c .­ + + +1 ti ;:) s u u 'ie o m hl'lilv\ri3d3cld 215kozur, aydin, demir, yakar, göncüoğlu & kuru: new stratigraphic and palaeogeographic results... pebbles of a beige, unmetamorphosed dolomite of prescythian/post-variscan age, apparently indicating reworking of late carboniferous or more probably permian shallow-water carbonates. this basal conglomerate is overlain by continental or shallow-marine sandstones in the typical facies of the alpine buntsandstein that are overlain by werfen beds (upper scythian yellowish-brown weathered marls, siltstones and limestones). after a hypersaline horizon with “rauhwacke” (yellowish-brown cellular dolomite and dolomitic marl, which is also common close to the olenekian-anisian boundary of the alps and western carpathians) typical alpine shallow-water anisian deposits are present (gutenstein limestone and steinalm dolomite, see below). such varied lithostratigraphic units as conglomerates, sandstones, siltstones, marls and marly limestones with the facies type of the alpine buntsandstein and werfen beds, as well as shallow-water platform carbonates (gutenstein limestone and steinalm dolomite) cannot be assigned to one formation, but only to several formations. therefore, the sırçalık “formation” is regarded as a group. special formation names were not proposed but the north alpine terms, such as werfen beds, gutenstein limestone and steinalm dolomite has been preliminarily applied. the middle triassic age dating of the shallow-water carbonates (aydin et al., 1995) has been confirmed. the shallow-water carbonates in the above mentioned section and in adjacent areas (e.g. at the roadcut between the villages of aha and sırçalık, locality 3 in fig. 1) consist mainly of gutenstein limestone and steinalm dolomite that is lying partly with erosive contact on the gutenstein limestone. the shallow-water carbonates and underlying typical werfen facies sediments (well exposed and not tectonically reduced along the road between aha and sırçalık) were previously dated as middle triassic on the basis of m e a n d r o s p i r a pusilla (ho), m e a n d r o s p i r a d i n a r i c a kochansky-dévidé & panti∆ and d a o n e l l a t a r a m e l l i mojsisovics by aydin et al. (1995). however, m . p u s i l l a is very characteristic for the upper scythian and confirms the late scythian (late olenekian, spathian) age of the typical werfen beds in this area. d a o n e l l a t a r a m e l l i from a slightly different position in the same beds is an incorrect determination. the densely ribbed bivalve that dr. m. aydin found from these beds during a joint excursion of the authors, is a scythian e u m o r p h o t i s, and surely not a d a o n e l l a that is, moreover, restricted to a totally different (pelagic) facies, whereas these werfen beds are shallowwater sediments. moreover, d a o n e l l a is not present during the scythian. as typical for scythian shallow-water limestones, the thin-sections of the “d a o n e l l a” limestones are very poor in microfossils but contain s p i r o r b i s p h l y c t a e n a brönnimann & zaninetti as a typical microfossil of scythian shallow-water limestones and m e a n d r o s p i r a p u s i l l a as a characteristic spathian foraminifer. also by dissolving of the material no pelagic ladinian microfossils were found that are always very common in d a o n e l l a-bearing limestones. instead, pyritised microgastropods and some (non-d a o n e l l a ) small bivalves are common, as are also typical for the shallowwater werfen facies. the pyritised fossils were oxidised into iron oxide. on the other hand, the anisian age for the shallowwater carbonates indicated by m . d i n a r i c a has been confirmed by the characteristic lithofacies of these beds. they consist mostly of gutenstein limestone (black micritic, partly dolomitic limestones, very poorly fossiliferous, a restricted shallow basin facies), and steinalm dolomite that overlies the former partly with erosive contact. exactly the same facies succession and relations of these lower to middle anisian rocks can be found at the shelves of the cimmerian meliata h a l lstatt ocean in the western carpathians and eastern alps. this facies association was present there before the opening of the meliatahallstatt ocean in the uppermost lower anisian to pelsonian and, consequently, can be found in the lower part of the shelf sequences on both sides of that ocean (kozur, 1991a, b). the transition between the werfen beds and the anisian shallow-water carbonate platform is developed in exactly the same manner as in the northern calcareous alps and western carpathians, the hypersaline horizon at the olenekian-anisian boundary with intensively yellowish brownish weathered dolomitic marls and cellular dolomite (“rauhwacke”) is also present at the road cut between the aha and sırçalık villages (locality 3 in fig. 1). this typical shallow-water development of the scythian to middle triassic sırçalık group is a characteristic north alpine facies shallow-water succession, widely distributed in the eastern alps and western carpathians. 2.2.2. serveçay group the serveçay group consists of low-grade metamorphic phyllites, mafic metatuffs, calcituffites, metadiabases and crystalline limestones (marbles). radiolarites are absent but silicified metasediments are present. the type locality is the zerveçay creek valley section south of gemiçiler (evrenye) at the gemiçiler haramid ağ road (locality 2 in fig. 1). at the type locality, the oceanic, low grade metamorphic zerveçay group is disconformably overlain by the scythian part of the deformed but unmetamorphosed sırçalık group beginning with a basal conglomerate. this discovery is decisive important for the upper age of the serveçay group that must be of pre-triassic age, probably a variscan metamorphic basement. as unmetamorphosed pre-triassic, probably permian dolomite pebbles occur in the lower triassic basal conglomerate, a pre-permian age for the serveçay group is indicated. therefore, the middle triassic upper age range for the “pa l a e o t ethyan” metamorphics of the küre complex (aydin et al., 1995) cannot be confirmed. 216 geologia croatica 53/2 the serveçay group was assigned to the bekirli group by aydin et al. (1995), but they also included the unrelated and unmetamorphic sırçalık group in their bekirli group, the type locality of which is at bekirli village in the elekdağ massif (yilmaz & tüysüz, 1988). the original bekirli unit was described by yilmaz & tüysüz (1988, p. 79) as “a tectonic unit with basic lava-pelitic sediment alternation, starts with garnet-glaucophane-bearing basic lavas grading into basic lava-pelitic schist alternation. towards top, metamorphism decreases and sedimentary rocks dominate over volcanic rocks. the uppermost part is a typical flysch sequence.” furthermore yilmaz & tüysüz (1988, p. 81) pointed out: “considering the stratigraphy and lithologies, it corresponds to the epiophiolitic cover of the palaeotethyan oceanic crust”. flysch sediments are not present in the serveçay group of the küre complex. the metamorphic overprint is also different; glaucophane is not present in the serveçay metamorphics. the so-called “palaeotethyan oceanic crust” of the middle pontides is middle triassic oceanic crust with back-arc geochemical character and therefore not palaeotethyan oceanic crust. if the geological situation of the bekirli unit in its type area is correctly interpreted, the type bekirli me t a m o r p h i c s should be of mesozoic age. subsequently, tüysüz et al. (1990) regarded the berkirli unit as a formation which overlies the elekdağ ophiolites (in the north), and the triassic kunduz mélange and the aktaş “ f o rmation” (sensu yilmaz et al., 1997) or aktaş “ m e t amorphic association” (yilmaz et al., 1997, p. 198) (assumed upper palaeozoic marbles and lower triassic mélange) of the karakaya complex (in the south). this also means that the type bekirli unit is an early mesozoic unit. according to yilmaz et al. (1997) there is a stratigraphic succession of metamorphic rocks which starts with the aktaş formation that contains upper carboniferous and permian fossils at its base. it is overlain by the gümüşo l uğu formation which consists of metapelites and metavolcancis with some marbles and ophiolite and marble blocks at the top. this formation is gradually overlain by the bekirli metamorphics which consists of metashales and metaflysch. according to yilmaz et al. (1997) the aktaşb e k i r l i succession indicates a transgressive triassic sequence above continental basement. “this sequence represents continental rifting and rupture of a pe r m o c a r b o n i f e rous continental platform, and then the rift evolved into a deep basin” (yilmaz et al., 1997, p. 199). according to this view, the bekirli metamorphics in the sense of yilmaz et al. (1997) are also mesozoic in age. however, what is interpreted as a stratigraphic succession may also be a structural succession and in this case the age of the bekirli metamorphics is unknown. however, the consensus from all papers on the bekirli metamorphics in its type area is that it seems to be an early mesozoic unit and, therefore, this name cannot be applied to the metamorphics of the küre complex which are clearly pre-permian in age. in silicified metasediments radiolarians are common in few thin-sections, but because of their bad preservation they cannot be determined. nevertheless, nassellaria are totally missing indicating a palaeozoic age. we regard the serveçay group as a variscan basement. as discussed above, the assumed upper age of the serveçay group as middle-upper triassic (aydin et al., 1995) could not be confirmed. this age was not assumed on the base of palaeontological /p a l y n o l o g i c a l or radiometric data, but on the erroneous assumption that the sırçalık “formation” is a sedimentary intercalation within the upper “bekirli” metamorphics (see under sırçalık group). the only date of the metamorphics of the serveçay group (311±6.2 ma) presented by aydin et al. (1995) indicates a carboniferous age in agreement with our assumption that the serveçay group represent a variscan basement. this is confirmed by variscan granitoids which intrude the metamorphic rocks of the serveçay group. they were dated by terzioğlu & satir (1997) as 308 ma by single zircon evaporation technique. 2.3. küre ocean unit this unit includes the akgöl group (largest part of the former akgöl formation sensu lato of keti . n , 1962, which had been revised several times e.g. aydin et al., 1995; kozur et al., 1997, 1999) as well as ophiolites and related oceanic assemblages (i . p s i n l e r basalt and ophiolites) which were previously also assigned to the akgöl formation s. l. 2.3.1. i . psinler basalt and ophiolites the i . psinler basalt mainly consists of pillow lavas, without essential sedimentary intercalations. it is part of a dismembered ophiolite that comprises serpentinised peridotite, layered cumulate gabbros, isotropic microgabbros, a sheeted dyke complex and pillow lava (güner, 1980; ustaömer & robertson, 1995). the ultramafics consist of serpentinised harzburgite of tectonite origin and and lerzolites which form small intrusive bodies in gabbros and basalt. trondhjemitegranophyres and altered plagiogranites are also present ( t e r z i oğlu et al., 2000). if the basalts are not olistoliths, the observed lower contact of the ophiolites is tectonic, as pointed out by ustaömer & robertson (1995). the upper contact may also be tectonic (e.g., slices of pillow lava within the akgöl group), but according to ustaömer & robertson (1995), the upper contacts are commonly undeformed sedimentary contacts. according to ustaömer & robertson (1995), the basalts belong to an ophiolitic sequence with supra-subduction chemical composition. they interpreted them as supra-subduction ophiolites of the northwards subducting karakaya ocean. however, this interpretation cannot be confirmed because there is no middle triassic lower carnian or older accretionary complex in the karakaya oceanic rift basin. the mafic 217kozur, aydin, demir, yakar, göncüoğlu & kuru: new stratigraphic and palaeogeographic results... volcanics and rarely also the ultramafics of the küre complex are already present as olistoliths in the middle carnian part of the karadağtepe turbidites. thus, these volcanics are pre-middle carnian and, therefore, cannot be related to the subduction of this very narrow oceanic basin. we regard them either as related to the northward subduction of palaeotethys which was situated south of the later izmir -ankara belt or the subduction signal is inherited from former southward subduction of the paphlagonian ocean. a similar situation is known from triassic rift-related basalts at the southern margin of tethys despite the fact that there is no southward (gondwana-) directed subduction at that time (dixon & robertson, 1999). according to these authors, the arc-type geochemical signature is generally believed to have been inherited from an earlier subduction-induced metasomatism and to reside in the lithospheric mantle. this explanation of a relatively recent inherited arc signature can be well applied for the i . psinler basalts because the küre ocean opened during the triassic on variscan basement and, moreover, the northward adjacent paphlagonian ocean was subducted southward during the middle late permian. the age of the i . psinler basalt is difficult to establish. sedimentary intercalations (dark shales), reported by ustaömer & robertson (1995) have not yielded fossils. all such sedimentary intercalations that we have seen are unfossiliferous tectonic slices of black shales. their age would not necessarily give the age of the volcanics. olistoliths of red radiolarites (found by m. aydin in the küre area), that could belong to primary sedimentary intercalations, are not exposed at present. k-ar dating yielded a dogger (bajocian) age for the basalts (170±6 ma, aydin et al., 1995, and 168±5 ma, terzioğlu et al., 2000) or an age close to the b e r r i a s i an /valanginian boundary (137±3 ma, 136±6 ma, terzioğlu et al., 2000). the bajocian age is not reliable because olistoliths of these basalts and of ultramafics are present in the middle to upper carnian part of the siliciclastic turbidites of the karadağtepe formation. thus, they must be older than middle carnian. also ustaömer & robertson (1997) did not consider the 170±6 ma date (aydin et al., 1995) as reliable in view of the low potassium content and hydrothermally altered nature of the basalts. the younger set was put into the upper tithonian by terzioğlu et al. (2000), but in recent papers, the tithonian -b e r r iasian boundary was placed at 144.2±2.6 ma (e.g. gradstein et al., 1994; menning, 1997) and the b e r r i a s i an -valanginian boundary at 137.0± 2.2 ma (e.g. gradstein et al., 1994) or around 136 ma (menning, 1997). they are therefore much younger than any rock of the küre complex, which is unconformably overlain by the upper jurassic bürnük formation and i . naltı formation and, consequently, must be older than these formations. therefore, these basalts cannot belong to the küre complex. however, they may belong to the kadi member, basalts within the uppermost beykoz formation. the oldest pelagic sediments from olistoliths which accompany the olistoliths of mafic and ultramafic rocks within the karadağtepe formation of the akgöl group are earliest anisian in age. very rare olistoliths of scythian sediments are pre-rift shallow-water sediments. thus, the age of the ophiolite and basalt olistoliths in the middle-late carnian part of the karadağtepe formation is middle triassic, probably ladinian (ladinian sediments are not dated among the olistoliths of the karadağtepe formation and may be represented by the above mentioned red radiolarites and shales). a middle triassic age is also assumed for those ophiolites or pillow lava that have a tectonic lower and sedimentary upper contact within the karadağtepe formation (as shown by ustaömer & robertson, 1995). these ophiolites and pillow lavas are regarded as synsedimentary (during the upper triassic subduction) obducted parts of the ocean floor within the accretionary complex. kimmeridgean basalts (aydin et al., 1995) may indicate an extensional regime in the jurassic e a r l y cretaceous turbidite basin (beykoz -ç ağlayan basin). these basalts are unrelated to the previously discussed basalts (and ophiolites). after completion of these investigations, ophiolite slices were found in black deep-water shales west of esentepe (east of locality 6 outside of the mapped area in fig. 1). they are accompanied by slices of pelagic limestones that yielded some foraminifers (under study). the immediately eastwards adjacent rocks of the k a r a d ağtepe formation yielded upper triassic t o r lessia. 2.3.2. akgöl group previously, four different entities were placed into the akgöl “formation”, three of which (the i . psinler basalt and ophiolites, karadağ tepe formation and an overlying unnamed formation) belong to the küre ocean unit of the küre complex, whereas the newly established çalça unit, which was also included into the akgöl “formation”, is an independent passive margin unit of the küre complex (fig. 2). only the karad ağtepe formation and the overlying unnamed formation belong to the akgöl (fig. 2) which has to be elevated to group rank. 2.3.2.1. karadağtepe formation this formation consists of dark siliciclastic turbidites with olistostromes. very few fossils (some badly preserved sporomorphs of triassic age) were previously reported until now from the matrix of this formation (alişan et al., 1992; aydin et al., 1995) but sporomorphs from the turbidites are mostly reworked. moreover, except the long-ranging v i t r e i s p o r i t e s p a l l i d u s (reissinger) nilsson, all other forms are only determined to genus level or the species determination was indefinite (cf.). 218 geologia croatica 53/2 rich associations of the enigmatic fossil t o r l e s s i a and trace fossils (pl. 15) were discovered in the matrix. two different species of t o r l e s s i a are present in the k a r a d ağtepe formation. both species also occur in new zealand (kozur, unpubl.), where they can be dated by radiolarians. t o r l e s s i a n. sp. (pl. 15, fig. 1) has a middle to late carnian age (kozur et al., in press b) and t. m a c k a y i bather (pl. 15, fig. 2) is of lower to middle norian age. this age of t. m a c k a y i i s also confirmed by an early to middle norian age of t o r l e s s i a m a c k a y i in the antalya nappes, where this species is very common in beds which could be dated by conodonts (kozur, 1998). both species can be partly found in stratigraphic superposition in the karadağtepe formation, t o r l e s s i a n. sp. in the lower part and t. mackayi in the middle part of the karadağtepe formation. therefore, for the first time, exact dating of the lower and middle karad ağtepe formation is possible. a middle carnian to middle norian age for this part of the karadağtepe formation is indicated. the upper karadağtepe formation and the overlying molasse type shallow-water part of the akgöl group are not yet dated. this interval is younger than middle norian and older than the overlying upper jurassic rocks. the rich trace fossil associations of the karadağtepe formation (e.g., c h o n d r i t e s , few h e l m i n t h o i d a, p s y c o s i p h o n, several new ichnotaxa, but no p a l e o d i c t y o n) indicate deep-water, but probably a water depth above the ccd, probably around 1,000 to maximum 2,000 m. the olistoliths of the karadağtepe formation are exotic pebbles, consisting of small clasts of middle triassic basalts (see above) and a few ultramafics, mainly small clasts of marginal ocean-floor sediments (black radiolarites, partly with sporomorphs of early anisian age, pl. 1, figs. 7-10; few red radiolarites), and above all of partly large blocks of a fossil-rich middle triassic oceanic slope sequence consisting of shallow-water, and mainly slope and basinal limestone (pl. 3, figs. 1-3, 5, 6; pl. 4; pl. 5, figs. 1-11; pls. 6-10; pl. 11, figs. 1-9; pls. 11-13; pl. 14, figs. 1-10). the oldest pelagic rocks contain conodonts and other microfossils of the chiose lla timorensis zone of the basal anisian (pl. 7, figs. 1215; pls. 8, 9; pl. 10, figs. 1-3). palaeopsychrosphaeric ostracods of the cold oceanic bottom water are present from the upper aegean (lower anisian) n e o g o n d o l e l l a ? regalis zone onwards (pl. 12, figs. 6-10; pl. 13; figs. 1-9). olistoliths of the sırçalık group and serveçay group are generally not present in the karadağtepe formation, except for small olistoliths of metamorphics from the serveçay group and a single olistolith of a red continental, probably lower triassic sandstone from locality 5 west of devrekani (fig. 1). thus, the olistoliths in the karadağtepe formation were mainly derived from an ocean slope north of the sırçalık shallow-water platform (with its serveçay metamorphics variscan basement). clasts of obducted ocean floor are also present. this is typical for an active margin setting. 2.3.2.2. unnamed lithostratigraphic unit it consists of mainly thick sandstones with siltstone and shale intercalations, some thin coaly layers and also some conglomeratic layers. land plant remains are present. these beds have a molasse character and are distributed beyond the karadağtepe formation. these shallow-water sediments overlie the sırçalık group or the serveçay group and contain a lot of reworked local material. similar rocks of the akgöl group also overlay the karadağtepe formation, but a gradual contact has not been observed anywhere. they may overlie the k a r a d ağtepe formation either discordantly or tectonically. a formal formation name has not yet been established for these shallow-water deposits of the akgöl group but these rocks are genetically very different (no turbidites of an accretionary complex, but shallowwater clastics on a carbonate platform or metamorphic basement and partly also covering the accretionary complex) from the karadağtepe formation (siliciclastic turbidites and olistostromes of an active margin). 2.4. çalça unit this unit is the passive margin sequence of the küre ocean and consists of pelsonian to upper norian or lowermost rhaetian hallstatt limestones, overlain by grey to dark-grey marly siltstones and shales of rhaetian to at least early jurassic age with large slided blocks of hallstatt limestones of north alpine type. these rocks, well exposed around the çalça village are not only sedimentologically, but also different in the age from the akgöl group. the akgöl group consists of middle carnian to middle jurassic, carbonate-free siliciclastic rocks without a shelly macrofauna. in its largest part (karadağtepe formation) it consists of turbidites and olistostromes. the çalça unit also consists of deep-water deposits (but well above the ccd), but turbidites are not present. however, the çalça unit begins at least during the middle pelsonian (until now oldest dated hallstatt limestone), whereas the upper age range is seemingly the same as for the akgöl fo rmation. during deposition of the siliciclastic turbidites of the karadağtepe formation at the active southern margin of the küre ocean, the deposition of condensed hallstatt limestones without any clastic input continued throughout the pre-rhaetian upper triassic at the passive, opposite (northern) margin of the ocean. only during the rhaetian and lower jurassic did the sedimentation of marls with shelly macrofaunas begin, and shortly before the closure of the ocean during the middle jurassic, as the active southern margin was close to the passive northern margin, deepening and tectonic unrest caused the sliding of blocks from the northern outer shelf and slope into the basin. they contain large masses of hallstatt limestones that are unknown from the akgöl group. the lithological differences between the akgöl group and the formations of the çalça un i t exclude the çalça unit from the akgöl group (or even formation, as in aydin et al., 1995). the obviously 219kozur, aydin, demir, yakar, göncüoğlu & kuru: new stratigraphic and palaeogeographic results... different depositional environments at the opposite margins of the ocean does not allow the placing of both units into one tectonostratigraphic unit. lithology, depositionary history and age are different. the çalça unit and the blocks of pelsonian to norian hallstatt limestones in it will be discussed in an independent paper by kozur et al. (in prep.). 2.5. upper jurassic lower cretaceous cover units the post-orogenic cover units (with respect to the cimmerian orogeny) of the küre complex and adjacent units area are represented by the bürnük, i . naltı, beykoz and çağlayan formations. 2.5.1. bürnük and i . naltı formations the bürnük formation consists of mainly red coloured conglomerates and sandstones of a transgressive series. it is overlain by the i . naltı formation consisting of upper jurassic platform carbonates that are thin-bedded in the lower part and thick-bedded in the upper part. the bürnük formation overlies with angular unconformity the accretionary complex of the akgöl group, and also rocks of the zonguldak terrane that was originally far north of the depositional area of the akgöl group. the bürnük and i . naltı formations belong therefore to a typical post-orogenic (with respect to the cimmerian orogeny) cover unit. the late jurassic age of the i . naltı formation is well documented by fossils (aydin et al., 1995). in the entire investigated area, the bürnük-i . naltı cover unit is only missing in the a z d a v ay -ağlı -d i k m e n d ağ area, where an extensional turbidite basin (beykozç ağlayan turbidite basin) opened above marginal parts of the küre complex or north of it. according to aydin et al. (1995) the beykoz formation, deposited within beykoz ç ağ layan turbidite basin, interfingers with the i . naltı formation both in the north and in the south. 2.5.2. beykoz unit in this study the beykoz formation and the overlying çağlayan formation are united to the beykoz unit. the relation of the beykoz unit to the küre complex was not investigated. however, the original position of the beykoz unit was north of the küre complex or /and it overlies its northern margin. 2.5.2.1. beykoz formation deep-water black shales and turbidites of a previously assumed upper triassic to malm age in the azdavay-ağlı -dikmendağ area has been discriminated by demir & özçelik (1987) and aydin et al. (1995) as the beykoz formation. they were deposited in an extensional basin above marginal parts of the küre complex or north of it, rather than in a compressional remnant basin of the küre ocean. the beykoz formation is overlain by lower cretaceous turbidites of the çağlayan formation. a new impulse of extensional tectonics is indicated in the uppermost beykoz formation by mafic volcanics (kadi member) and by an olistostromal conglomerate in the lower part of the overlying çağlayan formation. the age range of the beykoz formation is difficult to establish and is not the topic of the present paper. demir & özçelik (1987) and aydin et al. (1995) assumed a late triassic to malm age. however, we did not find any evidence for late triassic age. the h e l m i n t h o i d a dominated trace fossil association does not contain any of the characteristic new upper triassic ichnotaxa (kozur & yakar, in prep.; aydin & demir, in prep.) which are common in all upper triassic deep-water turbidites of the akgöl group. the ichnofauna of the “helminthoida flysch” in the beykoz unit is rather characteristic for jurassic and younger turbidites. the upper triassic t o r l e s s i a, which is very common in the karadağ tepe formation of the akgöl group, is missing even in the oldest beds of the beykoz formation. the youngest age of conglomerates and olistoliths in the beykoz formation is late jurassic. this is in agreement with the late malm age of the kadi basalt member and accompanying red marls in the upper beykoz formation (aydin et al., 1995). in those successions, in which the çağlayan formation begins during the valanginian or barremian, the beykoz formation may range into the lowermost cretaceous. as there are no fossil data for the lower beykoz formation that indicate a late triassic age, the beykoz formation is restricted to the extensional basin deposits of jurassic-earliest cretaceous age at present. the source area for the olistoliths and clasts of the conglomerates within the beykoz formation was quite different (north) from that of the akgöl group. there are clasts from the zonguldak terrane that is according to göncüoğlu & kozur (1998) and kozur & g ö n c ü oğlu (1999, 2000) the northernmost terrane of turkey which was after the closure of an ordovician-silurian deep-water trough a marginal part of the east european platform. thus, the jurassic-early cretaceous beykoz -ç ağlayan turbidite basin was south of stable europe adjacent to the zonguldak unit. in this position no remnants of the southern active margin of the cimmerian küre ocean should be present stratigraphically below the deposits of the jurassic l o w e r cretaceous extensional beykoz -ç ağlayan turbidite basin. this excludes the presence of late triassic flysch in the beykoz formation that was reported by aydin et al. (1995) independent from the fact that the presence of flysch would be in contrast to the correct statement by aydin et al. (1995) that the beykoz formation was deposited in an extensional basin. however, it is possible that the beykoz unit (beykoz fo r m a t i o n and çağlayan formation) is partly thrust from the north over the akgöl group of the küre complex. as the akgöl group and the beykoz formation are lithologically similar and often not well exposed, such a thrust may be difficult to recognise. 220 geologia croatica 53/2 olistoliths of middle triassic grey pelagic deepwater limestones and cherts which are common in the akgöl group, are not present in the beykoz formation. especially important is the presence of deep-water pelagic rocks (black radiolarites, pelagic limestones) of carboniferous, early and middle permian age. in one locality east of azdavay (locality 4 in fig. 1) a larger block is present that contains clasts of different sizes of upper carboniferous, lower and especially middle permian shallow-water, slope and basinal carbonates. moreover, clasts of permian debris flows are present that themselves contain clasts of carboniferous to middle permian pelagic and shallow-water rocks. obviously, in the source area of the beykoz clasts, a suture zone of a late palaeozoic ocean (the paphlagonian ocean), was exposed. the name paphlagonian ocean is derived from the ancient name of the area, in which these late palaeozoic deep-water sediments were found. 2.5.2.2. çağlayan formation this formation consists of shales, marls, silty marls, calciturbidites, turbiditic sandstones and olistostromes. it unconformably overlies with a thick conglomerate ( k a y a b oğazi member) the carbonate platform of the i . naltı formation. towards the beykoz ç ağlayan turbidite basin this conglomerate changes character, becoming a much thinner olistostromal conglomerate which overlies the beykoz formation without hiatus (aydin et al., 1995). often the çağlayan formation begins with andesitic volcanics (dikmendağ member). the age of the kayaboğazi member is not definitely known. sporomorphs from a marly intercalation within the conglomerates indicate a late jurassic age, but they may be reworked. overlying turbidites have an early cretaceous (valanginian to aptian) age (aydin et al., 1995). andesitic volcanics (dikmendağ volcanics) of the ç ağlayan formation have a k-ar age of 121± 3 my (aydin et al., 1995), indicating a latest barremian earliest aptian age. according to aydin et al. (1995), these volcanics erupted from extensional fractures and faults. this view seems to be correct because the çağlayan formation does not only overlie the basinal beykoz formation in the beykoz-ç ağlayan turbidite basin, but also overlies transgressively and unconformably the upper jurassic i . naltı carbonate platform north and south of the beykoz -ç ağ layan turbidite basin after breaking up and subsidence of the i . naltı shallow-water carbonate platform. the base of the çağlayan formation is diachronous, oldest in the central part of the basin and younger toward the marginal parts. with the exception of the upper jurassic sporomorphs of the kayaboğazi member that may be reworked, all other data give an early cretaceous age with valanginian or barremian for the lowermost sediments or volcanics of the çağlayan formation. 3. biostratigraphic results 3.1. age of the matrix of the karadağtepe formation (akgöl group) the more than 1500 m thick siliciclastic turbidite and olistostrome succession of the karadağtepe formation previously has not been precisely dated. the only reported fossils are very rare, badly preserved and tentatively determined sporomorphs (alişan et al., 1992; aydin et al., 1995) that indicate roughly a middle upper triassic age. however, in such turbidites the badly preserved sporomorphs are mostly reworked such as the permian sporomorphs in upper jurassic turbidites of the beykoz formation. the very thick, but lithologically monotonous karadağtepe formation cannot be subdivided by lithostratigraphic characteristics. ammonoids. conodonts, foraminifers, ostracods and radiolarians are absent from the matrix of the karadağtepe formation, and also pelagic bivalves (halobiids) which are often present in such facies, do not occur. however, we found a rich fossil association in the k a r a d ağtepe formation which allows both facies interpretation and stratigraphic dating and subdivision of the k a r a d ağ tepe formation. trace fossils are most common (pl. 15, figs. 3-6). chondrites is dominating, whereas helminthoida and psycosiphon are rare. several new and very characteristic ichnotaxa are present (kozur & yakar, in prep.; aydin & demir, in prep.) and some of these forms occur outside the middle pontides in the antalya nappes, where they are restricted to upper triassic turbidites. the absence of paleodictyon in the deep-water ichnofacies of the karad ağtepe formation indicates either poor water circulation or a depositional depth at the oxygen minimum zone (around 2,000 m water depth). it rather excludes abyssal water depth. the enigmatic fossil t o r l e s s i a, white or beige slender hollow cones with a fine-grained, siliceous, rather thick shell (see kozur et al., in press b) is very common. two different associations of t o r l e s s i a w e r e found. the lower association contains strongly curved forms (pl. 15, fig. 1), whereas the upper association consists of the straight or only slightly curved torlessia m a c k a y i bather (pl. 15, fig 2). t o r l e s s i a was for a long time only known from new zealand (e.g., bather, 1906; webby, 1967; hannah & collen, 1995; hannah & campbell, 1996). monod (1977, pl. 10) illustrated torlessia for the first time outside new zealand from the antalya nappes of southern turkey, but he did not recognise that it was t o r l e s s i a and regarded it as a fossil inc. sedis. subsequently, prof. dr. john douglas campbell, lower hutt, recognised t o r l e s s i a m a c k a y i in the antalya nappe. using his determination, şenel et al. (1996) reported the presence of torlessia in the antalya nappe for the first time. in 1997, kozur studied with the help of dr. j.e. simes, lower hutt, the red rock locality (sinclair head) at wellington, new zealand, where both torles 221kozur, aydin, demir, yakar, göncüoğlu & kuru: new stratigraphic and palaeogeographic results... s i a m a c k a y i and radiolarians were formerly reported (e.g., hannah & campbell, 1996; grapes et al., 1990). the well illustrated radiolarians (grapes et al., 1990) occur in a horizon with phosphorite nodules. they are late carnian in age. kozur recognised two horizons with t o r l e s s i a at sinclair head, the lower one stratigraphically below the radiolarian horizon contains strongly curved forms as in the lower torlessia horizon of the karadağtepe formation. these forms were figured by hannah & collen (1995) and hannah & campbell (1996) under t o r l e s s i a m a c k a y i b u t belong to a new species (kozur et al., in prep.). in a newly discovered horizon with t o r l e s s i a s t r a t i g r a p h ically above the radiolarian horizon at the red rock locality the straight or very slightly curved t. mackayi and a further new species (campbell & kozur, in prep.) are present. from this stratigraphic position in the section and the fact that t. m a c k a y i occurs only below the upper norian monotis-bearing beds, an early to middle norian age for t. m a c k a y i s. s . in new zealand can be concluded. despite the fact that monod (1977) did not recognise that this fossil inc. sedis is t. m a c k a y i he discovered that this fossil is restricted to the norian of the antalya nappes. kozur (1998) found numerous well preserved t. m a c k a y i in the antalya nappe exclusively in beds that can be dated by conodonts as lower and middle norian. thus, t. m a c k a y i is from new zealand to turkey a lower to middle norian indicator, whereas t o r l e s s i a n. sp. seems to be a middle to upper carnian indicator. unfortunately, its lower range is unknown. however, in upper ladinian siliciclastic beds with dao n e l l a l o m m e l i (wissmann) of burma, t i t a h i a b i r m i nica thein is common which seems to be a torlessia. this species is distinctly different from the upper triassic t o r l e s s i a of new zealand and turkey. thus, obviously, t o r l e s s i a n. sp. does not yet occur in the late ladinian. consequently, it begins either in the lower or in the middle carnian. therefore, the lower and middle karadağtepe formation can be assigned to the middle carnian -m i d d l e norian interval and already in the field, the middlelate carnian and the early-middle norian part of the karad ağtepe formation can be easily distinguished. in the upper karadağtepe formation no t o r l e s s i a is present. this part is late norian and younger. 3.2. age of the olistoliths in the akgöl group the lithologic character, facies and age of the olistoliths in the olistostromes within the karadağtepe formation are very important for the reconstruction of the geological evolution at the southern margin of the küre ocean in the middle pontides. moreover, these data are important for establishment of the lower boundary of the karadağ tepe formation. we have investigated numerous limestone olistoliths and one lydite olistolith from the karadağ tepe formation turbidites (with middle-upper carnian torlessia n.sp. and upper triassic trace fossils in the matrix) at the küre-inebolu road (locality 1 in fig. 1) and from a roadcut at the kastam o nu inebolu road 3 km west of devrekani (and an outcrop 300 m north of it; both outcrops are locality 5 in fig. 1). at locality 1, the olistoliths consist of pelagic and shallow-water limestones (pl, 3, figs. 1-3, 5, 6; pl. 4), black radiolarites, basalts and small clasts (mainly detritus) of ultramafics. the grey limestone olistoliths can be subdivided into two groups, shallow-water carbonate platform limestones and pelagic limestones (slope limestones, partly with reef or other shallow-water debris, and basinal, marly limestones). both the shallow-water platform carbonates and the pelagic limestones are of anisian age. the shallow-water limestones are partly sediments of a shallow-water platform (in the lower anisian) with a very restricted fauna, and partly backreef deposits with a richer and more diversified fauna and flora (foraminifers, ostracods, algae). the pelagic limestone olistoliths include limestones from the upper slope with a strong input of shallowwater bioclasts (especially in the lowermost anisian), and basinal deposits (mainly toe of slope), in which bioclasts and sedimentary clasts from the slope and shelf are rare or missing (this facies is very common in olistoliths from the upper part of lower anisian through pelsonian and illyrian). the youngest pebbles (exclusively pelagic limestones) are of late illyrian (latest anisian) age. no younger pre-akgöl sediments have been found in these pebbles despite the fact that every microfacies has been sampled and investigated. the age of the pelagic and slope facies olistoliths was mainly determined by conodonts and holothurian sclerites, the age of the shallow-water limestones by foraminifers, mainly according the data by baroz et al. (1990), rettori (1994, 1995), rettori et al. (1994), uro©evi∆ (1988) and zaninetti et al. (1987, 1994). as there is no evidence for a ladinian part of the akgöl group, ladinian clasts of the shelf margin and slope did not reach the marginal part of the ocean that was probably covered by shales, a few red cherts and mafic volcanics; the latter are common in the clasts. black shale and turbidite clasts could not be dated but they are facially very similar to the karadağtepe formation of the akgöl group and probably represent reworked lowermost karadağtepe formation. the rich microfauna of the anisian pelagic limestones consists of conodonts, holothurian sclerites, foraminifers, silicified ostracods (pls. 8, 9; pl. 10, figs. 1-9; pls. 11-13; pl. 14, figs. 1-10) and radiolarians (the latter could not be dissolved from the rocks because they are calcified). the rich occurrence of conodonts allows an exact dating of all pelagic limestone samples, whereas the ostracods yield important biofacial data. palaeopsychrosphaeric deep-water ostracods (pl. 12, figs. 810; pl. 13, figs. 1-9) begin in the second conodont zone of the anisian (n e o g o n d o l e l l a ? r e g a l i s zone). they indicate that cold oceanic bottom-water currents rea222 geologia croatica 53/2 ched this area during that time. the only investigated small lydite pebble was very rich in radiolarians which could not be extracted from the chert by dissolving with hf. however, the lydite only contains a monotonous spumellaria and entactinaria fauna with very few species indicating that it is probably not younger than early anisian. this black radiolarite contains sporomorphs (pl. 1, figs. 7-10), an exceptional facies that is also known from upper lower anisian black radiolarites of the south-rudabányaicum (southern slope of the meliata-hallstatt ocean) in hungary. according to dr. c. alişan, ankara, the sporomorphs indicate a late carboniferous to early permian age (investigation in the tpao). according to the determinations by kozur, the sporomorph association with platysaccus leschiki hart, striatoabieites balmei klaus, triadispora epigona klaus a n d t r i a d i s p o r a sp. indicates a middle triassic, most probably early anisian age. locality 5, about 3 km west of devrekani (fig. 1) has no torlessia in the matrix, and upper triassic trace fossils are also absent. thus, the matrix of the akgöl group is in this area younger than middle norian. the debris-flow is almost free of matrix and several metres thick in places. the olistoliths contain no mafic volcanics, ultramafics and radiolarites. therefore, in contrast to locality 1, no remnants of obducted ocean floor are present among the olistoliths. the olistoliths consist mostly of grey limestones, relatively few shallow-water platform carbonates, mainly slope, toe of slope and basinal marly, nodular filamentous limestones that are sometimes very rich in ammonoids, bivalves and crinoids, and also contain a few brachiopods. a single olistolith of a red (permo-)scythian sandstone and few very small metamorphic olistoliths of the serveçay group as well as black shale and turbidite olistoliths of the lower karadağtepe formation are also present. from these olistoliths it can be concluded that the source area of the debris flow was mainly a carbonaterich slope deposit with a rich macrofauna (ammonoids, bivalves, brachiopods, crinoids), partly already covered by sediments of the lower karadağ tepe formation. additional clasts were transported from a metamorphic source area and its (permo-) scythian cover, indicated by abundant clastic mica in the matrix, small metamorphic clasts and a continental red sandstone olistolith. as in locality 1, all limestone olistoliths have an anisian age, but the lowermost two conodont zones of the anisian (c h i o s e l l a t i m o r e n s i s zone and n e o g o n d o l e l l a ? r e g a l i s zone) are either not represented by pelagic limestones or olistoliths of this age were not processed. the analyses of the pebbles from the karadağt e p e formation led to the following interpretation: the küre ocean opened by the breaking up of a pre-existing carbonate platform on a low-grade metamorphic hercynian basement. this platform yielded shallow-water material into the basin until the middle or even upper anisian. the oldest pelagic rocks are from the lowermost conodont zone of the anisian, the chiosella timo r e n s i s zone. the representatives of c h i o s e l l a in this sample are still very primitive indicating an age at the scythian-anisian boundary. the limestone is a shallow pelagic sediment with a very rich fauna. it indicates an early stage of the breaking up of the carbonate platform that began in the uppermost scythian. rapid deepening is indicated for the following lower anisian zones (n e o g o n d o l e l l a ? r e g a l i s to n . b u l g a r i c a zones in ascending order), where the input of bioclasts from the shelf and slope drastically decreased and in the n e o g o n d o l e l l a ? r e g a l i s zone (upper aegean, lower anisian) palaeopsychrosphaeric ostracods appeared for the first time, which indicate a broad connection to the world ocean (cold oceanic bottom water currents reached the depositional area). therefore, the küre basin was since the early anisian no longer a narrow rift basin, but already an oceanic basin. in the upper anisian calciturbidites are also present. 3.4. age of the olistoliths or pebbles in the beykoz formation olistostromes and conglomerates of the beykoz formation contain three groups of olistoliths and pebbles: (1) rocks from the originally adjacent zonguldak terrane, (2) upper jurassic shallow-water limestones of the i . naltı formation, (3) exotic rocks. only the latter rocks were investigated. however, the other olistoliths and pebbles are also important for palaeogeographic interpretation and for the age of the matrix, in which the exotic olistoliths or pebbles are present. taking into consideration that the overlying çağlayan formation is well dated as early cretaceous (valanginian to aptian), the presence of upper jurassic olistoliths or pebbles indicate that the matrix of the beykoz formation in the investigated area is latest jurassic to earliest cretaceous (berriasian) in age. however, in those outcrops, where we found the exotic deep-water carboniferous and permian rocks, we could not date the matrix of the beykoz formation. all triassic biostratigraphic indicators of the akgöl group are missing and therefore, we conclude that the matrix of the beykoz formation in these localities is jurassic. however, late jurassic shallowwater limestone olistoliths are also missing. at locality 4 (see below), beside dominant olistoliths of exotic pelagic and shallow-water late palaeozoic a few olistoliths of permo-triassic red sandstones from the zonguldak unit are present. this indicates that during the deposition of the beykoz formation in this locality the continental permo-triassic rocks of the zonguldak unit were not yet covered by the upper jurassic carbonate platform. this probably indicates a liassic to dogger age for the matrix of the beykoz formation at this locality. a little north of locality 4, n and ne of the b i l â l b ağiköy village, where we found carboniferous black radiolarite, blocks of shallow-water limestones are also present that previously were regarded as upper 223kozur, aydin, demir, yakar, göncüoğlu & kuru: new stratigraphic and palaeogeographic results... jurassic in age. however, the investigated 5 samples from these blocks yielded permian shallow-water fossils. thus, the age of the matrix of the beykoz formation in that locality is also unclear. when really no upper jurassic shallow-water limestone blocks are present, then a lower and middle jurassic age of the matrix of the beykoz formation is most probable also at that locality. our investigations have concentrated on an outcrop north of dağ mahallesi east of azdavay (locality 4 in fig. 1). in this section a 5 x 1.5 m large block is exposed that consists of a nearly matrix-free debris flow that contains bioclastic shallow-water limestones with numerous permian algae, foraminifers and partly also small ammonoids, dark-grey, pelagic, marly limestones, and rarely grey bioclastic limestones with crinoids and brachiopods. additionally, smaller pelagic limestone olistoliths and a few olistoliths of red continental permotriassic sandstones are present in this locality. the limy matrix of the debris flow block is not yet dated because it consists only of millimetre-thin limestone between the clasts. however, it is not identical to the surrounding siliciclastic matrix of the beykoz formation. thus, it is a lithified pre-beykoz debris flow. its age is as young as or younger than the youngest dated clast of capitanian age; a late permian age is most probable. some of the clasts themselves are lithified debris flows with clasts of pelagic and shallow-water rocks. most of the olistoliths have a guadalupian (roadian to capitanian) age; the pelagic deep-water rocks have mostly unspecific faunas of carboniferous to permian age (pl. 1, figs. 1-6; pl. 2). conodonts are very rare and with one exception only ramiform elements of gondolellids were found. they are more advanced than carboniferous forms but a triassic age can be excluded according to the foraminiferal fauna. therefore, most of the pelagic rocks have a permian age. this age is also supported by the pelagic ostracods mostly comprised of cypridinids which are more advanced than middle carboniferous ones and more primitive than lower triassic cypridinids (mostly p e r m o c y p r i d i n a m o c k i n. g e n . n.sp., pl. 10, fig. 10), indicating a late carboniferous to permian age. one investigated olistolith (sample 1966/148) of wordian age is a clast of a lithified debris flow with clasts of shallow-water and pelagic limestones. it is a rudstone with micritic matrix and components of wackestone and mudstone. fossils from the insoluble residues and from thin sections include: tubiphytes obscu r u s maslov (algae), bryozoans, reworked juvenile s t r e p t o g n a t h o d u s sp. ex gr. s. r u z h e n c e v i k o z u r , echinoderm remains, small foraminifers d i p l o s p h a e r i n a sp., g l o b i v a l v u l i n a sp., l u n u c a m m i n a s p . , p a c h y phloia sp., tolypammina sp., fusulinids (a neoschwage r i n a fragment), gastropods and ostracods (partly pelagic). the depositional environment of this clast is the proximal slope (pelagic with transported contemporaneous, mostly broken, shallow-water fossils and reworked older material, pl. 1, fig. 4; pl. 14, fig. 11). this sample is very interesting for the interpretation of the facies of the source area. it indicates that pelagic deposition in the source area of the block was present at least from the late carboniferous (streptognathodus ex gr. s. ruz hencevi is a gzhelian conodont) up to the capitanian or rather post-capitanian time. debris flows on the steep margin of the basin were present at least from the wordian to capitanian / post-capitanian time. a further very interesting facies is represented by the olistolith of sample 1996/140. it is a well-washed bioclastic grainstone with a little pelmicritic matrix, mostly sparitic cement and partly incrusted bioclasts. the insoluble residues yielded only indeterminable shallow-water fossils, mainly algae and bryozoans. the following fossils were determined in thin-sections: a l g a e : t u b i p h y t e s c a r i n t h i a c u s ( f l ü g e l ), archaeo lithoporella sp., mizzia sp., ammonoids (pl. 1, fig. 3; pl. 3, fig. 4), brachiopods, bryozoans, small foraminifers: g l o b i v a l v u l i n a v o n d e r s c h m i t t i reichel, palaeotextulariidae indet., geinitzinidae, diplosphaerina sp., lower guadalupian types of fusulinids (p a r a f u s u l i n a ? sp.), gastropods and ostracods. this limestone was deposited at the shelf edge. it is a shallow-water limestone, but contains drifted small ammonoid shells. 600 m ne and 400 m n of the bilâlbağiköy village, a little north of locality 4, olistoliths or pebbles occur in the badly exposed beykoz formation which comprise permian shallow-water limestones, permian pelagic limestones and black radiolarites of carboniferous age. unfortunately, the radiolarian fauna of the radiolarites is badly preserved and it consists exclusively of entactinaria of carboniferous character which do not allow a more specific age determination, but it is older than late pennsylvanian. these samples have not been investigated and, therefore, the localities are not indicated in fig. 1. as a whole, the olistoliths and pebbles of exotic rocks in the beykoz formation indicate the following: most of the shallow-water permian clasts are from the shelf edge or from the upper reef slope; coral debris is often present. in addition pelagic micritic limestones with bathypelagic deep water ostracods are common. all transitions between the shallow-water and basinal facies were found that are represented by different slope facies, from pelagic toe of slope facies with only a few transported shallow-water clasts to upper slope sediments with large shallow-water clasts. the age of the shallow-water and slope limestone could be determined from foraminifers including fusulinids as guadalupian (all 3 stages, roadian, wordian and capitanian are present, but roadian and wordian rocks are most common). the pelagic deep water sediments yielded only new species (and mainly new genera) of bathypelagic cypridinidae and rather unspecific foraminiferal faunas of late carboniferous to permian age. most probably, these fully pelagic beds are also mainly of guadalupian age as are most of the slope deposits, but some are older. part of the slope deposits 224 geologia croatica 53/2 are themselves debris flows. they contain clasts of shallow-water and pelagic limestones. the latter are as old as gzhelian (upper carboniferous) as indicated by the conodont streptognathodus sp. ex gr. s. ruzhencevi. this indicates both persistent pelagic conditions (carboniferous to at least capitanian) and repeated debris flows over a long time interval (at least from the wordian to the capitanian or rather post-capitanian time). these facts and the common occurrence of bathypelagic cypridinid ostracods indicate a persistent late palaeozoic basin environment. however, the scarcity or absence of conodonts even in favourable slope facies is striking. this was also observed in blocks from the eskiorda tectonic complex of se crimea, in which no conodonts were discovered despite analysing several kg of ammonoid-bearing limestones. in contrast, the facially similar permian limestones from palaeotethys in the crete islands and sicily yielded very rich conodont faunas. in the middle and upper permian of neotethys (oman, iran and sicily) conodonts are very common, sometimes >1 , 0 0 0 specimens per kg sample. thus, obviously, this northernmost permian ocean at the se-margin of the east european platform had no direct n-s deep-water connection to other permian oceans of western tethys and may be in the permian already a rather restricted basin. 4. comparison of some units of the middle pontides with assumed equivalents in se crimea, and the palaeotethys problem the correlation of the middle pontide units with the se crimea units is difficult because the latter are neither stratigraphically nor structurally well investigated. marcoux et al. (1993), marcoux & baud (1996), robinson & kerusov (1997) and kotlyar et al. (1999) correlated the akgöl “formation” with the taurida flysch s. l . (tauric flysch, tavric flysch, tauridian flysch: different spelling by different authors; as taurida is the old name of crimea, we prefer the term taurida flysch as used by kotlyar et al., 1999). however, as pointed out by kotlyar et al. (1999), the akgöl group contains only triassic olistoliths, but no late palaeozoic blocks (olistoliths). our new results have solved this contradiction. our discovery of olistoliths of carboniferous and permian pelagic rocks in the beykoz unit, has proven for the first time the existence of these olistoliths of exotic late palaeozoic also in the middle pontides. in the permian, mainly guadalupian of se crimea shallow-water and pelagic, ammonoid-bearing limestone olistoliths and bashkirian and younger carboniferous shallow-water olistoliths are present (tumanskaya, 1916, 1931, 1937, 1941; miklucho-maklay & miklucho-maklay, 1966; popadyuk & smirnov, 1996; kotlyar et al., 1999). olistoliths of this age and facies are also common in the beykoz unit of the middle pontides. additionally, gzhelian (late pennsylvanian) pelagic limestones with conodonts and carboniferous radiolarites have been found in the middle pontides, but radiolarite olistoliths were probably not investigated in se crimea and may also be present there. in the se crimea dzhulfian and dorashamian olistoliths were directly dated by small foraminifers. olistoliths of this age were not yet proven in the middle pontides, but post-capitanian late permian olistoliths may also be present in the middle pontides, e.g. the undated matrix of an olistolith, which consists of a debris flow with pelagic and shallow-water upper carboniferous to capitanian clasts. the occurrence of an exceptional permian facies of shallow-water limestones with small ammonoids (see above) that were obviously post-mortally drifted shells is especially interesting. such olistoliths occur both in the se crimea and in the middle pontides. olistoliths of exotic pelagic late palaeozoic rocks do not occur in the akgöl group. despite the fact that they were reported from the taurida flysch in se crimea, they obviously do not occur in the taurida flysch s. s . they are only present in the eskiorda tectonic complex (eski-odra formation sensu popadyuk & smirnov, 1996, a misspelling for the second part of the word, and eskiorda unit sensu kotlyar et al., 1999; the spellings eski-orda or eskiorda are correct) in se crimea. generally, the eskiorda tectonic complex is regarded as part of the taurida flysch and dated as middle triassic to middle jurassic. however, according to kotlyar et al. (1999), the north dipping eskiorda unit, a composite and dismembered tectonic complex, lies north of the taurida flysch s. s ., but also occurs in two places (bodrak and marta river valleys) overthrust southward on the taurida flysch. they assigned the eskiorda tectonic complex to the ladinianb a t h o n i a n interval. according to popadyuk & smirnov (1996) the “eski-odra formation” is part of the taurida flysch (taurian group according to popadyuk & smirnov, 1996). they regarded the “eski-odra formation” and with it their taurian group as early cretaceous on the base of an earlier discovery of hauterivian-aptian ammonoids in the “eski-odra formation”. formerly reported pre-cretaceous fossils were assumed to be derived from olistoliths. the taurida flysch s. s. (without the northward adjacent and partly overthrust eskiorda tectonic complex) is unconformably overlain either by upper jurassic rocks, very similar to the bürnük and i . naltı formations of the middle pontides (south and east of the kacha uplift) or by lower cretaceous deposits in the north and west. thus, at least that taurida flysch s. s . which is overlain by upper jurassic rocks is surely older than late jurassic. its facial development and known fossils indicate a late triassic to middle jurassic age, but mostly it is unclear whether the fossils are from the matrix or from olistoliths. nevertheless, the taurida flysch s. s . and its upper jurassic cover are very similar to the akgöl group of the middle pontides and its upper ju r a s s i c 225kozur, aydin, demir, yakar, göncüoğlu & kuru: new stratigraphic and palaeogeographic results... cover. both units can be well compared in agreement with former correlations by marcoux et al. (1993), marcoux & baud (1996), robinson & kerusov (1997) and kotlyar et al. (1999). carboniferous and permian exotic olistoliths are not present in this part of the taurida flysch s. s., as they are not present in the akgöl group. the eskiorda tectonic complex, which contains the exotic carboniferous and permian blocks, obviously corresponds to the beykoz unit. it is situated north of the taurida flysch s. s . (and partly overthrust on it) as the beykoz unit is situated north of the küre complex. regarding this structural setting, the age of the eskiorda tectonic complex cannot be transferred to the taurida flysch s. s . and, therefore, the early cretaceous age assigned to the taurida flysch on the base of the assumed early cretaceous age of the eskiorda tectonic complex by popadyuk & smirnov (1996) cannot be accepted, independently from the question, whether the eskiorda tectonic complex is regarded as a part of the taurida flysch (upper taurida flysch) s. l . or as an independent unit as in kotlyar et al. (1999). we prefer the latter solution. the age of the eskiorda unit is not clear. generally, a liassic (sinemurian to toarcian) age has been assumed, and late sinemurian to pliensbachian fossils were reported, but they may be at least partly reworked. popadyuk & smirnov (1996) reported early cretaceous (hauterivian to aptian) ammonoids from the eskiorda tectonic complex which would indicate an aptian upper age range of this unit (as for the çağlayan formation of the beykoz unit in the middle pontides). according to dr. a.m. nikishin, moscow (pers. comm.), these ammonoids do not occur inside the eskiorda tectonic complex, but in a mélange-like zone at its margin. this left the age of the eskiorda tectonic complex open. we do not correlate the eskiorda tectonic complex with the akgöl group as has been done previously (as a part of the taurida flysch or also as an independent unit by kotlyar et al., 1999), but with the beykoz unit. both units are shallower than the akgöl turbidites ( k a r a d ağtepe formation) and taurida flysch turbidites, and contain exotic, partly deep-water carboniferous and permian blocks. both are situated north of upper t r i a s s ic l o w er /middle jurassic siliciclastic deep sea flysch of the akgöl group and taurida flysch s. s . respectively which contain only olistoliths of triassic exotic rocks. the mirroring of some tectonic units in the middle pontides and se crimea (akgöl group taurida flysch s. s., beykoz unit eskiorda tectonic complex) indicates that these units were subsequently separated by the black sea that opened a little obliquely to the strike of the beykoz-eskiorda tectonic complex and akgöl g r o up taurida flysch s. s ., leaving part of it in the se crimea (taurida flysch s. s. and eskiorda tectonic complex) and the other part at the opposite side of the black sea, in the middle pontides (akgöl group and beykoz unit) fig. 3. the olistoliths of pelagic upper carboniferous to permian rocks in the jurassic beykoz formation of the middle pontides and in the eskiorda tectonic complex of se crimea are good evidence for the existence of a late palaeozoic northern “palaeotethys” in the sense of the şengör school (e.g., şengör & yilmaz, 1981; şengör, 1984, 1985; şengör et al., 1984; genç & yilmaz, 1995; yilmaz et al., 1997). the accretionary complex of this ocean was obviously one of the source areas of the clasts in the beykoz formation of the middle pontides and in the eskiorda tectonic complex of se crimea. an other source area of the clasts in the beykoz formation was the zonguldak terrane (fig. 3) which was a marginal part of the east european platform (stable europe) since the devonian according to göncüoğlu & kozur (1998), kozur & göncüoğlu (1999, 2000) and kozur & stampfli (2000). consequently, the “palaeotethys” in the sense of the şengör school was situated at the southern margin of stable europe (zonguldak terrane), north of the variscan chain. kahler (1939) established the palaeotethys as an ocean and its shelves north of the later tethys. the axis (suture zone) of the tethys sensu kahler (1939) was shown along the zagros zone and from there toward the east to an area roughly between the indian craton and tibet. it corresponds to neotethys s. s . ( s t ö c klin, 1974, 1977; stampfli, 1978; kozur, 1999), a term which was established by stille (1944a, b) in his geosynclinal concept (lower pennsylvanian to tertiary geosyncline, not an ocean) which cannot be applied in any mobilistic reconstruction. therefore we use the plate tectonic neotethys concept by stöcklin (1974, 1977) and stampfli (1978) because it has priority among the plate tectonic concepts of neotethys. the palaeotethys concept of kahler (1939) was too wide. whereas the southern margin of his palaeotethys was well defined (immediately north of gondwana and after the middle permian opening of neotethys, north of the cimmerian continent as a splinter of gondwana), the northern margin of his palaeotethyan shelf was drawn with the northern occurrence of permian shallow-marine deposits. therefore, both stöcklin (1974, 1977) and stampfli (1978) on one side, and şengör (1979) on the other side presented a restricted scope of palaeotethys within the original palaeotethys of kahler (1939). the revised palaeotethys sensu stöcklin (1974, 1977) and stampfli (1978) has priority and represents an ocean and not a geosyncline as in concept by stille (1944a, b). consequently, it is used here. the palaeotethys sensu şengör (1979) consists in western tethys of two different oceanic units adjacent to the southern margin of laurussia and within the northern part of the variscan chain respectively: a (devonian) carboniferous to permian ocean adjacent to the southern margin of laurussia, which we named the paphlagonian ocean, and the middle triassic to middle 226 geologia croatica 53/2 a b c fig. 3 schematic n-s cross section through the middle pontides. legend: a) upper triassic: southward subduction of the küre ocean below the küre ridge. this caused the beginning of the rifting in the later vardar ocean in the izmir-ankara zone (not shown). deposition of the turbiditic-olistostromal karadağtepe formation of the akgöl group over the down-thrust northern margin of the küre ridge and the adjacent marginal oceanic part of the küre basin. korb karakaya oceanic rift basin. b) lower dogger: the southwards subduction of the remnant küre ocean continued. some synsedimentary obducted slices of the basalts and ophiolites in the karadağtepe formation are over lain by the upper karadağtepe formation. the subduction also caused granitic intrusions. the molasse type upper akgöl group covers not only the karadağtepe formation, but also the largest part of the küre ridge and lies transgressively over the sırçalık and serveçay groups. the karakaya oceanic rift basin closed during the late norian, and the turbidite-olistostrome complex is transgressively overlain by the sazak group. in the south, oceanic crust is created in the vardar ocean of the izmir -ankara belt. c) upper jurassic: the küre ocean is totally subducted and its accretionary complex as well as adjacent units are covered by the i . naltı shallow-water carbonate platform. the extensional beykoz basin opened adjacent to the zonguldak terrane north of the akgöl accretionary complex or on marginal parts of it. the suture zone of the paphlagonian ocean is exposed at the northern margin of the beykoz-çağlayan turbidite basin and rocks of this zone and subordinately those of the zonguldak terrane are transported into the beykoz-çağlayan turbidite basin. the somewhat oblique future black sea rift (upper cretaceous) is indicated that cut in the west the southernmost part of stable europe, leaving the zonguldak unit on the southern side of the black sea rift. in the east, the black sea rift cut the beykoz unit, leaving a part of it in the se crimea at the northern margin of the black sea rift (taurida flysch), the other part on the southern margin of the black sea rift (beykoz unit of the middle pontides). 227kozur, aydin, demir, yakar, göncüoğlu & kuru: new stratigraphic and palaeogeographic results... jurassic küre ocean that opened in the northern marginal part of the variscan chain (sakarya) south of the suture zone of the paphlagonian ocean. additionally, variscan oceanic sequences (serveçay group of the küre ridge unit) were put in the “palaeotethys” sensu şengör (1979). the opening time of the paphlagonian ocean is not yet known. until now, the oldest fossil-proven pelagic rocks are black radiolarites of carboniferous age and also in the exotic olistoliths in se crimea the oldest rocks are serpukhovian early bashkirian. if the paphlagonian ocean opened in that time, it would be related to the closure of the variscan ocean further in the south (both in the istanbul terrane and in olistoliths of the late triassic diskaya unit of the karakaya oceanic rift basin, the youngest pelagic variscan rocks are early bashkirian in age kozur, 1999; kozur & gönc ü oğlu, 2000). in this case it would be a marginal trough north of the variscan sakarya continent. the other possibility is that the paphlagonian ocean opened during the late early devonian in prolongation of the northernmost variscan ligiha ocean of middle and western europe. it may have opened in direct connection to the ligiha ocean or in the same position as this ocean within the formerly accreted margin of laurussia. whereas in middle and western europe both the ligiha ocean in the north and the palaeotethys in the south closed during the carboniferous, further in the east both oceans remained open and closed only at the end of the permian (paphlagonian ocean) and during the middle carnian (palaeotethys). in the crimea a late palaeozoic fold belt is present containing metamorphosed devonian m i s s i s s i p p i a n deep-water shales and volcanic rocks, including remnants of a volcanic arc (nikishin et al., in press). lower carboniferous black shales sw of sevastopol (nikishin et al., in press) may also belong to this basin. the bashkirian-permian deep-water basin with a restricted connection to the world ocean was perhaps a remnant basin of this ocean. the visean deformation phase was not connected with closure of this ocean. the term “palaeotethys” can neither be applied for the combined paphlagonian and küre oceans (and the splinter of variscan basement) which were together assembled into the “palaeotethys” sensu şe n g ö r (1979) nor for the northern (and older) of these two oceans alone because it contradicts the priority re-definition of palaeotethys by stöcklin (1974, 1977) and stampfli (1978) as a late palaeozoic-triassic ocean between perigondwana in the south and the variscan chain in the north. for this reason, the northern ocean at the margin of the east european platform has been named the paphlagonian ocean. the suture zone of the priority palaeotethys sensu stöcklin and stampfli lies south of the later izmir-ankara belt. its remnants were found recently in the tavas composite nappe of the lycian nappes in the western taurus by kozur et al. (1998) who suggested variscan lower carboniferous flysch as the oldest palaeotethyan flysch, and by kozur & şenel (1999) and kozur et al. (in press c), who discovered tectonically underlying younger palaeotethyan successions, such as pennsylvanian morb and oceanic sea-mount successions, as well as a triassic foreland basin in front of the advancing cimmerian nappes). 5. results and discussions (1) as both the karakaya oceanic rift basin and the küre ocean were early mesozoic oceans, all three former models of the geological evolution of the karakaya oceanic rift basin and the küre ocean (1 küre ocean the late palaeozoic to middle jurassic palaeotethys, and karakaya oceanic rift basin its back-arc basin; 2 karakaya oceanic rift basin the late palaeozoic to triassic palaeotethys and küre ocean its back-arc basin; 3 karakaya oceanic rift basin and küre ocean represent the later separated remnants of the large late palaeozoic to middle jurassic palaeotethys) cannot be confirmed. (2) the küre complex is not the remnant of a persistent late palaeozoic jurassic palaeotethyan ocean as assumed by the şengör school (e.g., şengör & yilmaz, 1981; şengör, 1984, 1985; şe n g ö r et al., 1984; genç & yilmaz, 1995), but a middle triassic to middle jurassic ocean. it opened as a back-arc basin during the latest scythian. however, its opening is not related to the subduction of a persistent late palaeozoic triassic karakaya ocean as assumed by okay et al. (1996), pickett et al. (1995), ustaömer & robertson (1995, 1997, 1999), pickett & robertson (1996), but to the northward subduction of palaeotethys, the suture zone of which is south of the later izmir ankara belt. remnants of this palaeotethys (morb and oib, as well as pelagic carboniferous to triassic oceanic sediments and late pennsylvanian ocean island sediments) were found in the tavas composite nappe of the lycian nappes (kozur et al., 1998; kozur & şenel, 1999; göncüoğlu et al., 2000; kozur et al., in press c). the subduction of the rather broad küre ocean started during the middle carnian and continued until the middle jurassic closure of this back-arc ocean. (3) the karakaya ocean is a narrow (transtensional) oceanic rift basin in the eurasian marginal belt (shelf) of palaeotethys. it existed only from the uppermost permian to middle norian. its opening is not related to the southward subduction of the küre ocean because the karakaya oceanic rift basin opened before the beginning of subduction of the küre ocean. however, the closure of the narrow ka r akaya oceanic rift basin may be related to the southward subduction of the küre ocean because it was filled up by the siliciclastic turbidites and olisto228 geologia croatica 53/2 stromes of the diskaya unit which started exactly at the same time as the southward subduction of the küre ocean. (4) the missing subduction signal in the mafics of the karakaya ocean does not indicate that this ocean was the huge palaeotethyan ocean, but that its opening was unrelated to the subduction of palaeotethys and of the küre ocean. the opening of the karakaya oceanic rift basin is related to the collapse of the variscan cordillera (sakarya continent). continuing collapse of the variscan orogene and northward subduction of palaeotethys finally creates the opening of back-arc oceans, such as the küre ocean. further to the west, an analogous development caused by the collapse of the variscan cordillera can be observed in the early rifting (late permian) in the area of the later maliak ocean, but in contrast to the karakaya oceanic rift basin it did not develop an oceanic rift stage before the late triassic (or late ladinian). further collapse of the variscan orogene and continuous northward subduction of palaeotethys led to the opening of the meliatah a l l s t a t t back-arc ocean during the anisian. slab roll-back in the palaeotethys led to a southward shift of back-arc sea-floor spreading from the meliata back-arc ocean into the maliak back-arc ocean during the late ladinian or early carnian. southward subduction of the meliata ocean and of its eastern continuation, the küre ocean, opened the vardar ocean from the vardar belt to the izmir-ankara belt. (5) the subduction direction of the karakaya oceanic rift basin is disputed. this is mainly consequence of the fact that with the onset of flysch sedimentation siliciclastic turbidites were present in the entire basin and therefore no active and passive margin can be lithologically distinguished. the other reason is the very complicated tectonic situation which makes it nearly impossible to recognise the general tectonic dipping. most authors prefer a southward subduction (e.g., şengör & yilmaz, 1981; şengör et al., 1984; genç & yilmaz, 1995; okay et al., 1996; kozur & mock, 1997). according to pickett et al. (1995) and ustaömer & robertson (1995, 1997, 1999) there was a northward subduction of the karakaya oceanic rift basin. in their opinion this caused the opening of the küre back-arc basin, which is impossible because the küre ocean opened during the late scythian whereas no evidence for early and middle triassic subduction of the karakaya oceanic rift basin can be found. ustaömer & robertson (1997) pointed out that the basement units of the karakaya complex exhibit a consistently northward-dipping foliation, and the axial planes of fold and thrust planes also dip northward. if this structural evidence can be confirmed, then subduction in the karakaya oceanic rift basin was really directed northward. however, in the structurally very complicated karakaya complex it is very difficult to establish the subduction direction, if no passive margin sequence can be recognised. thus, pickett & robertson (1996) accepted the main subduction of the karakaya oceanic rift basin toward the south, but believed that also a northward-directed subduction was present. this would be in conflict with the previously mentioned structural data. moreover, such a narrow rift basin as the karakaya oceanic rift basin would surely not subduct into two opposite directions. okay (2000) also changed his former view of a southward-directed subduction into the northward-directed subduction of the karakaya oceanic rift basin without new structural data, and this contradicted his view of a single karakaya-küre ocean which subducted below the european margin. the northern margin of the küre ocean is clearly a passive margin with anisian to norian hallstatt limestones and rhaetian liassic shales and marls. with exception of okay (2000), there is general agreement that the küre ocean subducted toward the south. this is proven by the discovery of anisian to norian hallstatt limestones at the passive northern margin which were, in the carnian and norian, contemporaneous with the siliciclastic flysch at the southern active margin of the küre ocean. it is possible that there was southward subduction only in the küre ocean and none in the karakaya oceanic rift basin. if the ridge between the küre ocean and the karakaya oceanic rift basin was elevated with the onset of the southward subduction of the küre ocean, then this ridge yielded terrigenous siliciclastic rocks both toward the southern active margin of the küre ocean (akgöl group) and toward the karakaya oceanic rift basin (diskaya unit). as the karakaya oceanic rift basin was very narrow, turbidites of this clastic input filled the entire basin. in this case, the nilüfer unit may be a northward subducted palaeotethyan sea-mount which was suddenly brought to the surface perhaps by the onset of the southward subduction of the küre ocean. this would be one possible explanation for the fact that middle carnian to middle norian turbidites of the diskaya unit overlie the hp/lt metamorphic rocks of the nilüfer unit. the other possibility would be that the within plate volcanics of the nilüfer unit do not indicate a sea-mount but early rifting stage of the karakaya oceanic rift basin. this would be in better agreement with the succession within the nilüfer unit (table 1), however, it would require a rather unusual development of blueschist facies without very deep, subduction related tectonic burial. such an explanation seems to be possible because within the nilüfer unit the metamorphic overprint changes from very low grade in its upper part to blueschist facies in its lower part in a distance of a few kilometres. a third explanation 229kozur, aydin, demir, yakar, göncüoğlu & kuru: new stratigraphic and palaeogeographic results... for the nilüfer unit would be that it represents a sequence of the late permian early triassic rift stage of the küre ocean which cannot be found in the küre basin because it was totally southwardsubducted under the küre ridge unit and the karakaya rift basin. as the karakaya rift basin was during the upper triassic in its transpressional stage and the nilüfer unit is a relatively light slab (not only mafic tuffs and volcanics are present, but also thick shallow-water carbonates in its lower part and thick shales in its upper part), a rapid exhumation during the upper triassic is possible. (6) the küre complex consists of three oceanic and continental units with different evolution paths and palaeogeographic positions. these are the küre ridge unit (the variscan serveçay group and the sırçalık group, its lower -middle triassic shallowwater cover) in the south, the central küre ocean unit (middle triassic basalts, ophiolites, and middle carnian to middle jurassic accretionary complex of the akgöl group) and the çalça unit (northern passive margin and slope of the küre ocean). the palaeotethys sensu şengör (1979, 1984, 1995) comprises all three units, a variscan complex (serveçay group) and its disconformably overlying lower and middle triassic shallow-water cover, as well as the middle triassic middle jurassic küre ocean (its middle carnian to middle jurassic accretionary complex from the active southern margin, obducted ophiolites and mafic volcanics, and its northern passive margin sequence). (7) the serveçay group is a variscan low-grade metamorphic oceanic unit of pre-triassic (pre-permian) age. it is a part of the variscan sakarya continent. it is overlain by a deformed but unmetamorphosed triassic shallow-water sequence that begins with a scythian transgressive quartz conglomerate also containing a few pebbles of unmetamorphosed dolomites of post-variscan / pre-triassic (probably permian) age. (8) the deformed, but unmetamorphosed sırçalık group is not an intercalation within the upper serveçay group, and it is also not ladinian in age as assumed by aydin et al. (1995). it disconformably overlies the serveçay group and begins with the above mentioned transgressive conglomerate. sandstones and siltstones in the facies of the alpine buntsandstein, werfen beds, a hypersaline horizon with cellular dolomites at the olenekian-anisian boundary, anisian gutenstein limestone and steinalm dolomite follow in a shallow-water shelf triassic sequence of typical north alpine character. a formerly assumed upper ladinian part with d a o n e l l a t a r a m e l l i m o jsisovics cannot be confirmed. this “d a o n e l l a ” has been derived from the werfen beds and is a misidentified scythian e u m o r p h o t i s. the late olenekian (spathian) age of this part of the sırçalık group is proven by m e a n d r o s p i r a p u s i l l a ( h o ) , s p i r o r b i s p h l y c t a e n a brönnimann & zaninetti (pl. 5, figs. 12, 13), and e u m o r p h o t i s sp. the anisian age of the platform carbonates is proven by foraminifers (e.g. meandrospira dinarica k o c hansky-dévidé & panti∆). (9) the akgöl “formation” sensu aydin et al. (1995) represents the following different sequences that belong to the küre ocean unit: middle triassic ophiolites and mafic volcanics (obducted ophiolites and pillow lavas, tectonic slices and olistoliths), karadağtepe formation, an unnamed formation consisting of a shallowwater sequence of ungraded sandstones, siltstones and shales. additionally, the newly established çalça unit, a passive margin succession, was also included previously into the akgöl “formation”. the karadağtepe formation and the unnamed formation belong to the akgöl group. (10) the karadağtepe formation represents a siliciclastic accretionary complex at the southern, active margin of the küre ocean with remnants of the obducted oceanic crust (ophiolites, pillow lava). the matrix of the lower and middle karadağtepe formation was dated by the succession of t o r l e s s i a n.s p . (middle to upper carnian) and t o r l e s s i a m a c k a y i (lower and middle norian) as middle carnian to middle norian. trace fossils indicate deep-water conditions for the turbidite-olistostrome sequence. the upper karadağtepe formation has a late norian to early or middle jurassic age. olistoliths of the deep-water turbidites of the karadağtepe formation contain shallow-water, slope and basinal limestone, radiolarites (all of anisian age), red radiolarites of probably ladinian age, middle triassic mafic volcanics and ophiolites. the ophiolites and mafic volcanic clasts are part of a pre-carnian oceanic crust. as there are no basinal and slope sediments older than basal anisian, a middle triassic age for the oceanic crust can be assumed. it was obducted early during the late triassic middle jurassic southward subduction because ophiolite and mafic volcanics are already present as olistoliths in the middle to upper carnian part of the karadağtepe formation. a middle triassic age is also assumed for tectonic slices of ophiolites and thick pillow lavas in the küre area, that all have a tectonic lower contact and partly a sedimentary upper contact (ustaömer & robertson, 1995). as fully pelagic, open sea faunas with chiosella t i m o r e n s i s, the conodont guideform of the pelagic lowermost anisian, are present in the olistoliths of the karadağtepe formation, the opening of the küre oceanic basin was within the latest olenekian. 230 geologia croatica 53/2 (11) an unnamed shallow-water sandstone-siltstoneshale sequence with coaly layers overlies (? unconformably, contact relations not observed) the karadağtepe formation. these beds of molasse character also unconformably overlie the sırçalık and serveçay groups. there, they contain only pebbles of local character which were derived from the sırçalık and serveçay groups. (12) the çalça unit is an anisian to lower or middle jurassic deep-water sequence from the passive (northern) margin of the küre ocean. it consists of pelsonian (middle anisian) to norian or lower rhaetian hallstatt limestones that have the same lithofacies and fossil content as the north alpine and western carpathian hallstatt limestones, and r h a e t i an liassic marls with brachiopods and trace fossils. due to the extraordinary palaeogeographic importance of the discovery of hallstatt limestones in the investigated area, their fauna and age will be discussed in a separate paper. the dating is based on well preserved conodonts that are very common and have a cai = 1 (within the oil window). ammonoids are also common, but were not collected. for palaeogeographic evaluation it is very important that during the upper triassic deposition of siliciclastic turbidites and olistostromes of the accretionary complex at the active southern margin of the küre ocean, the deposition of the strongly condensed hallstatt limestones without any clastic input continued at the slope of its passive northern margin. thus, the küre basin was rather broad at the end of the triassic, and its subduction continued during the lower and middle jurassic. (13) numerous important micropalaeontological results were obtained from the olistoliths in the akgöl group. conodonts, foraminifers, holothurian sclerites and other echinoderm remains, ostracods, fish remains and sporomorphs have been studied and evaluated both stratigraphically and biofacially. stratigraphically important pelagic conodonts were found from the lowermost anisian c h i o s e l l a timorensis zone up to the upper anisian neogondo l e l l a c o n s t r i c t a zone. as the conodonts are well preserved, no taxonomic problems arose. for species present see pl. 8, figs. 1-10; pl. 10, figs. 4-9; pl. 11; pl. 12, figs. 1-5; pl. 13, fig. 10; pl. 14, figs. 14, 6-10. the conodont alteration index (cai) in the k a r a d ağtepe formation of the akgöl group is 3-4 and, consequently, a little above the “oil window” (kozur et al., 1997). foraminifers yielded important stratigraphic data for olistoliths both of shallow-water and pelagic limestones, but also for the sırçalık group. in these rocks algae (only in shallow-water limestones) and sometimes ammonoids, brachiopods, bivalves, fish remains and occasionally s p i r o r b i s (only in shallow-water limestones) were also present. for present species see pls. 5-7; pl. 8, fig. 11; pl. 9, figs. 1-4; pl. 10, fig. 1. holothurian sclerites were previously nearly undescribed from turkey. only mostler (1968) described 3 t h e e l i a species form the upper anisian of northwestern turkey. in our material holothurian sclerites are known throughout the entire anisian. the lower anisian holothurian sclerites are the first of this age from western tethys. except t h e e l i a, also p r i s c o p e d a t u s , e o c a u d i n a , t e t r a v i r g a and other genera are present in our material and will be described in a separate paper. for some of the species present see pl. 9, figs. 5-7 and pl. 14, fig. 5. a s p i d o c r i n i t e s, echinodermata incertae sedis (pl. 10, figs. 2, 3), was found for the first time outside the alps, where it occurs in the pelsonian (kozur & mostler, 1992). our form is a new species from the lowermost anisian chiosella timoren sis zone. ostracods yielded very important palaeoecological data. in the lower anisian neogondolella ? rega lis zone and in younger faunas palaeopsychrosphaeric ostracods occur that indicate the presence of cold oceanic bottom water currents. (14) the küre complex and adjacent units are covered by an upper jurassic shallow-water carbonate platform (i . naltı formation). only in the azdavay-ağlı d i k m e n d ağ area (fig. 1), the i . naltı formation is missing and replaced by the upper jurassic turbidites of the beykoz formation. the beykoz -ç ağl ayan turbidite basin is probably not a compressional basin as the remnant of the küre ocean, but an extensional basin. it widened during the uppermost jurassic and lower cretaceous by the breaking up and subsidence of the i . naltı shallow-water carbonate platform (lower cretaceous turbidites of the çağlayan formation which overlay both the turbidites of the beykoz formation and the shallow-water i . naltı formation). (15) the olistostromes and conglomerates of the beykoz unit (beykoz formation and çağlayan formation) contain olistoliths and pebbles of rocks of the zonguldak terrane which, since the devonian, was a marginal part of the east european platform (gön c ü oğlu & kozur, 1998; kozur & gönc ü oğlu, 1999, 2000), of upper jurassic platform carbonates from the adjacent i . naltı formation, and of exotic pebbles. (16) the exotic olistoliths and pebbles of the beykoz formation (lower part of the beykoz unit) contain late pennsylvanian and early middle permian pelagic deep-water sediments (pelagic limestones, radiolarites), slope sediments and shallow-water limestones. wordian to capitanian or post-capitanian debris flows were also proven. this proves for the first time the existence of a persistent la t e 231kozur, aydin, demir, yakar, göncüoğlu & kuru: new stratigraphic and palaeogeographic results... palaeozoic ocean in the middle pontides that was predicted by the şengör school (a part of the “palaeotethys” by şengör & yilmaz, 1981; şengör, 1984, 1985; şengör et al., 1984; genç & yilmaz, 1995; yilmaz et al., 1997). however, its position was farther north than previously assumed, between the late palaeozoic stable europe margin (zonguldak terrane) in the north and the northernmost part of the variscan chain in the south (e.g. serveçay group of the küre ridge unit of the küre complex and other metamorphic variscan rocks that occur within the küre complex). as the name palaeotethys cannot be applied to this ocean for priority reasons, this oceanic basin is named the paphlagonian ocean. its remnants are also present in the eskiorda tectonic complex of se crimea at the opposite side of the black sea. this indicates that the formerly continuous eskiorda u n it -beykoz unit was separated by the somewhat oblique late cretaceous opening of the black sea. likewise, the flysch of the akgöl group of the middle pontides and the taurida flysch s. s . of se crimea are equivalent sequences which were separated by the opening of the black sea. (17) the origin of the paphlagonian ocean is not yet known. it may have opened in prolongation of the northernmost variscan oceanic branch (ligiga ocean; in that case not yet proven pelagic devonian rocks should be found). or it may have opened in a zone of crustal weakness in the broad transition zone between stable europe and the variscan chain. in this area also later oceanic basins or deep-sea basins on thinned continental crust opened (e.g. küre ocean, beykoz ç ağlayan turbidite basin, cretaceous intrapontide ophiolite belt = intrapontide “neotethys”; the term neotethys should be only used for the southernmost tethyan ocean that opened during the permian within gondwana and closed during the late cretaceous to late tertiary), and finally the black sea. (18) the repeated presence of debris flows at least from the wordian until the top of the guadalupian (or lopingian) may indicate subduction of the paphlagonian ocean during this time. the youngest known debris flow block contains capitanian clasts as the youngest rocks. it may be latest capitanian to late permian (lopingian: dzhulfian, dorashamian) in age. the eskiorda unit of se crimea also contains dated dzhulfian and dorashamian blocks. as neither the eskiorda unit of se crimea nor the beykoz formation of the middle pontides contain any pelagic rocks of early triassic age, the closure of the paphlagonian ocean probably occurred at the end of the permian or during the earliest triassic. (19) important palaeontological results were obtained from the exotic olistoliths and pebbles in the beykoz formation. the stratigraphic evaluation of the olistoliths and pebbles is mainly based on foraminifers, especially on fusulinids, in pelagic beds also on conodonts (e.g., the first evidence of pelagic upper carboniferous in northern turkey by the gzhelian s t r e p t o g n a t h o d u s ex gr. s. r u z h e n c e v i pl. 14, fig. 11) and bathypelagic ostracods. apart from these biostratigraphic results, these upper carboniferous and permian faunas are also biogeographically important. the fusulinids and small foraminifers, accompanied by algae, are an undoubtedly northern tethyan fauna and flora, whereas the provenance of the permian faunas and marine floras of the karakaya complex is disputed. we agree with leven (in leven & okay, 1996) that the permian associations of the karakaya complex also have a northern tethyan character, but other authors originate this fauna from gondwana (e.g., pickett & robertson, 1996; altiner et al., 2000). the often bathypelagic cypridinidae from the permian (guadalupian and older) blocks in the beykoz unit are the oldest permian pelagic fossils of turkey. moreover, cypridinidae are known from the carboniferous, rarely from the lower and middle triassic and mainly recent, but not from the permian. thus, p e r m o c y p r i d i n a m o c k i n.gen. n.s p . (pl. 10, fig. 10, description in a separate paper by kozur & yakar, in prep.) is an important link between the carboniferous and triassic cypridinidae. 6. conclusions the middle pontides are a geologically very complex area with repeated opening and closure of oceanic or suboceanic basins since the ordovician. by a posts i l u r i an pre-emsian caledonian event (folding, very low to low grade metamorphism, thermal alteration, göncüoğlu & kozur, 1998), the arenig to silurian deep-sea basin of the zonguldak terrane (with shallowing upwards sequence until the lowermost lochkovian) was attached to the margin of the east european platform (stable europe). the broad transition zone between stable europe and the variscan sakarya continent has been a tectonically very unstable area since the late palaeozoic. firstly, during the carboniferous (or devonian), the paphlagonian ocean opened, immediately south of the margin of stable europe (south of the zonguldak terrane). the southward subduction of this ocean during the middle and late permian (earliest triassic) and the northward subduction of palaeotethys south of the later izmir-ankara belt triggered the collapse of the variscan cordillera. the former variscan cordillera (sakarya continent) subsided, was at first (late pennsylvanian to artinskian interval) periodically, and then from the kungurian to dzhulfian permanently covered by shallow seas. continuing collapse of the variscan cordillera created the conditions for the latest permian (dorashamian) opening of the karakaya 232 geologia croatica 53/2 rift, which developed during the early and middle triassic to a narrow oceanic rift basin that filled up from the middle carnian by siliciclastic turbidites and olistostromes of the diskaya unit (junior synonym: hodul unit) and closed during the late norian. during the late olenekian, the küre ocean opened north of the küre ridge (part of the sakarya continent) and south of the suture zone of the paphlagonian ocean. the küre ridge (variscan metamorphics of the serveçay group and unconformably overlying shallowwater triassic) therefore became a continental “splinter” between two oceanic basins. the ocean floor basalts of the küre ocean show a back-arc signature. this is either caused by the northward subduction of palaeotethys or the subduction signal is inherited from a former southward subduction of the paphlagonian ocean and/or from the variscan subduction. the küre ocean was a rather broad ocean because in the late norian, more than 20 ma after the beginning of the subduction during the middle carnian, it was still so broad that the deposition of a clastic-free, condensed hallstatt limestone sequence at its passive northern margin continued contemporaneously with the deposition of siliciclastic turbidites and olistostromes of the k a r a d ağtepe formation at its active southern margin. this required an ocean width of more than 500 km close to the end of the triassic, also indicated by the fact that the subduction continued until the middle jurassic, when küre ocean was closed. subsequently, nearly the entire area was covered by the upper jurassic shallow-water carbonate platform of the i . naltı formation which is missing only in the a z d a v ay-ağlı -d i k m e n d ağ area. here, the extensional j u r a s s ic -lower cretaceous beykoz-ç ağlayan turbidite basin subsided north of the küre complex or on marginal parts of it. subsequently, during the (?uppermost jurassic) early cretaceous this turbidite basin considerably widened by the break-up and subsidence of the i . naltı carbonate platform and the turbidite deposition of the çağlayan formation started. the occurrence of exotic pelagic carboniferous and permian blocks (pelagic limestones and radiolarite) within the beykoz formation indicates that the beyk ozç ağlayan turbidite basin opened on or immediately south of the paphlagonian suture zone. the intrapontide ocean opened during the cretaceous and closed at the end of the cretaceous. its late cretaceous closure caused the opening of the black sea. as the black sea opened somewhat oblique to earlier structures, part of the akgöl group of the middle pontides can be found on the opposite side of the black sea, in se crimea (taurida flysch s. s .). the equivalents of the originally northward adjacent beykoz unit of the middle pontides with the blocks of exotic pelagic late palaeozoic are situated even to the larger part in se crimea (eskiorda tectonic complex north of the taurida flysch s. s. and partly thrust on it). the continuation of the küre ocean towards the west is the kotel zone in bulgaria and the northern dobrudzha in rumania, parts of the transylvanian nappes in eastern carpathians (romania) and the melia ta -hallstatt ocean in the western carpathians and eastern alps (kozur, 1991a, b, 1999; kozur & mock, 1997). fauna, lithological sequences and event successions in all these areas are very similar or identical. from the kotel zone westward, the subduction only began in the jurassic, but the closure occurred in all these areas in the late callovian early oxfordian interval. the opening of the oceanic basins began earlier toward the east, in the pelsonian (middle anisian) in the eastern alps, in the uppermost lower anisian in the easternmost alps and western carpathians, in the uppermost scythian in the eastern carpathians, and in the uppermost scythian in the northern dobrudzha, kotel zone and in the küre basin (kozur, 1999). acknowledgements we thank very much univ.-prof. h. mostler, innsbruck, prof. r. rettori, peruggia, prof. j. sremac, zagreb, dr. i. veli∆, zagreb, and doc. dr. w. resch, innsbruck, for their important help and support when reviewing the manuscript with particular regard to the foraminiferal determinations, and dr. c. jenny-deshusses, bernex, for useful critique of the permian foraminiferal data. we are also very grateful to dr. j. robson, southminster, for her language editing and very useful comments. 7. references a l işan, c., aköz, ö. & kirici, s. (1992): kastamonu, küre, azdavay yöresi 1990 yılı saha çalışmalarına ait örneklerin palinoloji, nannoplankton ve mikropaleontoloji analizleri.turkish petroleum corporation, exploration group, report no. 2965, ankara (unpublished). altiner, d. & koçyigit, a. (1993): third remark on geology of karakaya basin. an anisian megablock in northern central anatolia: micropaleontologic, stratigraphic and tectonic implications for the rifting stage of karakaya basin, turkey.rev. paléobiol., 12/1, 1-17. altiner, d., özkan-altiner, s. & koçyigit, a. (2000): late permian foraminiferal biofacies belts in turkey: palaeogeographic and tectonic implications.in: bozkurt, e., winchester, j.a. & piper, j.d.a. (eds.): tectonics and magmatism in turkey and the surrounding area. geol. soc. london, spec. publ., 173, 83-96. aydin, m., demir, o., özçelik, y., terzioğlu, n. & satir, m. (1995): a geological revision of inebolu, devrekani, ağlı and küre areas: new observations in palaeotethys-neotethys sedimentary successions.in: erler, a., ercan, t., bin233kozur, aydin, demir, yakar, göncüoğlu & kuru: new stratigraphic and palaeogeographic results... göl, e. & örçen, s. (eds.): geology of the black sea region. general dir. of min. res. and expl. & chamb. of geol eng., 33-38, ankara. baroz, f., martini, r. & zaninetti, l. (1990): un aspect de la plate-forme carbonatée triasique dans les hellenides internes: le chainon d’oreokastro.riv. it. paleont. strat., 96/1, 21-38. bather, f.a. (1906): the mount torlesse annelid.geol. mag., 5, 532-541. demir, o. & özçelik, y. (1987): kastamonu, daday, araç, boyalı, ilgaz civarının jeolojisi ve petrol olanakları.turkish petroleum corporation, exploration group, report no. 1369, unpublished. dixon, j.e. & robertson, a.h.f. (1999): are multiple plums implicated in the triassic break-up of the gondwanan margin in the eastern me d i t e rranean region?terra abstracts, 11, 314. genç, ş.c. & yilmaz, y. (1995): evolution of the triassic continental margin, northwest anatolia.tectonophysics, 243, 193-207. g ö n c ü oğlu, m.c. & kozur, h. (1998): remarks to the pre-variscan development in turkey.in: linnemann, u., heuse, t., fatka, o., kraft, p., brocke, r. & erdtmann, b.-d. (eds.): pre-variscan terrane analysis of “gondwanan europe”.schr. staatl. mus. min. geol. dresden, 9, 137-138, dresden. g ö n c ü oğlu, m.c. yaliniz, m.k. & floyd, p.a. (2000): petrology of the carboniferous volcanic rocks in the lycian nappes, sw turkey: implications for the late paleozoic evolution of the t a u r i deanatolide platform.international earth sciences colloquium of the aegean region, iesca 2000, abstracts, 213, izmir gradstein, f.m., agterberg, f.p., ogg, j.g., hardenbol, j., van veen, p., thierry, j. & huang, z. (1994): a mesozoic time scale.j. geophys. res., 99/b12, 24,052-24,074. grapes, r.h., lamb, s.h., campbell, h.j., spörli, b. & simes, j.e. (1990): geology of the red rocks-turbidite association, wellington peninsula, new zealand.new zealand journ. geol. geophys, 33, 377-391. güner, m. (1980): massive sulfide ores and geology of the küre area.mta dergisi, 93/94, 65-109. hannah, m.j. & campbell, h.j. (1996): t o r l e s s i a m a c k a y i and other foraminifera from the torlesse terrane, new zealand.new zealand journ. geol. geophys., 39, 75-81. hannah, m.j. & collen, j.d. (1995): an occurrence of the tube fossil t o r l e s s i a m a c k a y i b a ther, 1906 from southwest wellington, new zealand.new zealand journ. geol. geophys., 38, 117119. kahler, f. (1939): verbreitung und lebensdauer der fusulinidengattungen p s e u d o s c h w a g e r i n a und p a raschwagerina und deren bedeutung für die grenze karbon/perm.senckenberginana, 21/3-4, 169-215, frankfurt. kaya, o., wiedmann, j. & kozur, h. (1986): preliminary report on the stratigraphy, age and structure of the so-called late paleozoic and/or triassic “mélange” or “suture zone complex” of northwestern and western turkey.bull. earth sci., appl. res. centre hacettepe univ., yerbilimleri, 13, 1-16. k e ti . n, i . . (1962): 1/500.000 ölçekli türkiye jeoloji haritası i . zahnamesi.mta publication, ankara, 111 p. kotlyar, g.v., baud, a., pronina, g. p . , zakharov, yu. d., vuks, v.j.a., nestell, m.k., belyaeva, g.v. & marcoux, j. (1999): permian and triassic exotic limestone blocks of the crimea.in: crasquin-soleau, s. & de wever, p. (eds.): peri-tethys: stratigraphic correlations 3. geodiversitas, 21/3, 299-323. kozur, h. (1991a): the geological evolution at the western end of the cimmerian ocean in the western carpathians and eastern alps.zbl. geol. paläont., teil i, 1991/1, 99-121. kozur, h. (1991b): the evolution of the meliata hallstatt ocean and its significance for the early evolution of the eastern alps and western carpathians.palaeogeogr., palaeoclimatol. palaeoecol., 87/1-4, 109-135. kozur, h. (1998): the occurrence and stratigraphic importance of t o r l e s s i a m a c k a y i, an enigmatic fossil of the torlesse terrane (new zealand), in the akgöl group (küre complex, northern turkey) and in the antalya nappes (southern turkey).hallesches jahrbuch für geowissenschaften, reihe b, beiheft 5, 95-96, halle. kozur, h.w. (1999): permian development in the western tethys.in: ratanasthien, b. & rieb, s.l. (eds.): proceedings of the international symposium on shallow tethys (st). 5, 101-135, chiang mai. kozur, h.w., aydin, m., demir, o. & yakar, h. (1999): geological evolution of middle pontide area (northern turkey) and eastward continuation of the meliata-hallstatt ocean.geol. carpathica, 50, special issue, 154-155. kozur, h., aydin, m., demir, o., kuru, f. & yakar, h. (1997): possibilities of biostratigraphic and biofacial analyses in the bekirli me t a m o r p h i c s , akgöl group, beykoz unit and domuzdağ melange importance for the interpretation of the geological evolution in the area between küre and the bl a c k sea coast at inebolu.tpao report, ankara, 61 p. 234 geologia croatica 53/2 kozur, h.w., aydin, m., demir, o. & yakar, h. (1999): geological evolution of middle pontide area (northern turkey) and eastward continuation of the meliata-hallstatt ocean.geol. carpathica, 50, special issue, 154-155. kozur, h.w., demir, o., göncüoğlu, c.m. & yakar, h. (in press a): the age of the nilüfer formation in its type locality.hacettepe yerbilimleri. kozur, h.w., demir, o. & yakar, h. (in press b): torlessia, an enigmatic fossil from new zealand and turkey.paläont. z. kozur, h.w. & göncüoğlu, c. (1999): differences in the geological evolution of the istanbul and zonguldak terranes, northern turkey.in: talent, j., khan, f. & mawson, r. (eds.): international geological correlation program igcp 421: north gondwana mid-palaeozoic bioevent/biogeography patterns in relation to crustal dynamics. macquarie university printery, north ryde, 1618. kozur, h. & göncüoğlu, m.c. (2000): main features of the pre-variscan development in turkey.acta univ. carolinae, geologica 1998, 42/3-4, 459464, praha. kozur, h.w., göncüoğlu c.m., şenel, m., ueno, k. & floyd, p.a. (in press c): carboniferous successions of the tavas composite nappe (lycian nappes, western taurus, turkey): implications for the late paleozoic evolution of the taurides.eclogae geol. helv. kozur, h. & kaya, o. (1994): first evidence of pelagic late permian conodonts from nw turkey.n. jb. geol. paläont. mh., 1994/6, 339-347. kozur, h. & mock, r. (1997): new paleogeographic and tectonic interpretations in the slovakian carpathians and their implications for correlations with the eastern alps and other parts of the western tethys. part ii: inner western carpathians.mineralia slovaca, 29, 164-209. kozur, h. & mostler, h. (1992): erster paläontologischer nachweis von meliaticum und süd-rudabányaicum in den nördlichen kalkalpen (österreich) und ihre beziehungen zu den abfolgen in den westkarpaten.geol. paläont. mitt. innsbruck, 18, 87-129. kozur, h.w. & şenel, m. (1999): carboniferous oceanic sequences in the lycian nappes of southern turkey.xiv iccp, international congress on the carboniferous-permian, programme with abstracts, 79, calgary. kozur, h.w., şenel, m. & tekin, k. (1998): first evidence of hercynian lower carboniferous flyschoid deep-water sediments in the lycian nappes, southwestern turkey.geol. croatica, 51/1, 15-22. kozur, h.w. & stampfli, g. (2000): palaeozoic and early mesozoic development in turkey with special consideration given to the european and gondwana margins.geofiz. zhurn., 22/4, 103-105, kiev. leven, e.j.a. & okay, a.i. (1996): foraminifera from the exotic permo-carboniferous limestone blocks in the karakaya complex, northwestern turkey.riv. it. paleont. strat., 102/2, 139-174. marcoux, j. & baud, a. (1996): late permian to late triassic palaeoenvironments. three snapshots: late murgabian, late anisian, late norian.in: nairn, x., ricou, l.e., vrielinck, b. & dercourt, j. (eds.): the tethys ocean. plenum press, 153-190, new york, london. marcoux, j., baud, a., ricou, l.e., gaetani, m., krystan, l., bellion, y., guiraud, r., besse, j., gallet, y., jaillard, e., moreau, c. & theveniaut, h. (1993): late norian (212-214 ma).in: dercourt, j., ricou, l.e. & vrielinck, b. (eds.): atlas tethys, palaeoenvironmental maps, explanatory notes. gauthier-villars, 35-53, paris. menning, m. (1997): geologische zeitskala der mark brandenburg.in: stackebrandt, w., ehmke, g . & mahenke, v. (eds.) atlas zur geologie von brandenburg. landesamt für geologie und rohstoffe brandenburg, 74-75, kleinmachnow. miklucho-maklay, a.d. & miklucho-maklay, k.v. (1966): krymo-kavkazkaya alpijskaya skladchataya oblast.in: likharev, b.k. (ed.): stratigrafija sssr, permskaya sistema. nedra, 391402, moscow. monod, o. (1977): recherches géologiques dans le taurus occidental au sud de beyşehir (turquie).unpublished phd thesis, university of paris, 442 p. mostler, h. (1968): holothurien-sklerite aus oberanisischen hallstätter kalken.alpenkundliche studien, 2, 5-44. nikishin, a.m., ziegler, p.a., panov, d.i., nazarevich, b.p., brunet, m., stephenson, r.a., bolotov, s.n., korotaev, m.v. & tikhomirov, p.l. (in press): mesozoic and cainozoic evolution of the scythian platform black sea caucasus domain.in: ziegler, p.a., cavazza, w. & robertson, a.h.f.r. (guest eds.), crasquin-soleau, s. (ed.): peritethyan rift/ wrench basins and passive margins. peritethys memoir, 8, mém. mus. natn. hist. nat. okay, a.i. (2000): was the late triassic orogeny in turkey caused by the collision of an ocean plateau?in: bozkurt, e., winchester, j.a. & piper, j.d.a. (eds.): tectonics and magmatism in turkey and the surrounding area.geol. soc. london, spec. publ., 173, 25-41. 235kozur, aydin, demir, yakar, göncüoğlu & kuru: new stratigraphic and palaeogeographic results... okay, a.i. & mostler, h. (1994): carboniferous and permian radiolarite blocks from the karakaya complex in northwest turkey.tr. j. earth sciences, 3, 23-28, ankara. okay, a.i., satir, m., maluski, h., siyako, m., monie, p., metzger, r. & akyüz, s. (1996): palaeoand neo-tethyan events in northwestern turkey: geology and geochronologic constraints.in: yin, a. & harrison, t.m. (eds.): the tectonic evolution of asia. cambridge university press, 420-441, cambridge new york melbourne. okay, a.i., siyako, m. & bükan, k.a. (1991): geology and tectonic evolution of the biga peninsula, northwestern turkey.bull. techn. univ. istanbul, 44, 191-256. okay, a.i. & tüysüz, o: (1999): tethyan sutures of northern turkey.in: durand, b., jolivet, l., horváth, f. & séranne, m. (eds.): the mediterranean basins: tertiary extension with the alpine orogen. geol. soc. london, spec. publ., 156, 475-515. önder, f., boztuğ, d. & yilmaz, o. (1987): bati pontidlerdeki göynükdaği-kastamonu yöresi alt mesozoyik kayaçlarinda yeni paleontolojik (konodont) bulgular, bati pontidler, türkiye: melih tokay.jeoloji sempozyumu, bildiri özleri, 127-128. pickett, e.a. & robertson, a.h.f. (1996): formation of the late palaeozoic early mesozoic karakaya complex in nw turkey by palaeotethyan subduction-accretion.j. geol. soc. london, 153, 995-1009. pickett, e.a., robertson, a.h.f. & dixon, j.e. (1995): the karakaya complex, nw turkey: a palaeotethyan accretionary complex.in: erler, a., ercan, t., bingöl, e. & örçen, s. (eds.): geology of the black sea region. general dir. of min. res. and expl. & chamb. of geol eng., 11-18, ankara. popadyuk, i.v. & smirnov, s.e. (1996): crimean orogen: a nappe interpretation.in: ziegler, p.a. & horváth, f. (eds.): structure and prospects of alpine basins and forelands. peri-tethys memoir, 2, mém. mus. natn. hist. nat., 170, 513-524. ramov©, a. (1968): biostratigraphie der klastischen entwicklung der trogkofel-stufe in den karawanken und nachbargebieten.n. jb. geol. paläont., abh., 131/1, 72-77. rettori, r. (1994): replacement name h o y e n e l l a, gen. n. (triassic foraminiferida, m i l i o l i n a) for g l o mospira sinensis ho, 1959.boll. soc. paleont. italiana, 33/3, 341-343. rettori, r. (1995): foraminiferi del trias inferiore e medio della tethide: revisione tassonomica, stratigrafia ed interpretazione filogenetica.univ. genève, publ. dépt. géol. paléont., 18, 147 p. rettori r., angiolini, l. & muttoni, g. (1994): lower and middle triassic foraminifera from the eros limestone, hydra island, greece.j. micropalaeont., 13, 25-46. robinson, a.g. & kerusov, e. (1997): stratigraphic and structural development of the gulf of odessa, ukrainian black sea: implications for petroleum exploration.in: robinson, a.g. (ed.): regional and petroleum geology of the black-sea and surrounding region. mem. amer. ass. petrol. geol., 68, 183-226. şenel, m., gedik, i., dalkiliç, h., serdaroğlu, m., bilgin, a.z., uğuz, m.f., bölükb aşi, a.s., korucu, m. & özgül, n. (1996): isparta, büklümü doğusunda, otkoton ve allokton birimlerin stratigrafisi (bati toroslar).mta dergisi, 118, 111-160, ankara. şengör, a.m.c. (1984): the cimmeride orogenic system and the tectoncis of eurasia.geol. soc. amer. spec. paper, 195, 82 p. şengör, a.m.c. (1985): die alpiden und die kimmeriden: die verdoppelte geschichte der tethys.geol. rdsch., 74, 181-213. şengör, a.m.c. & yilmaz, y. (1981): tethyan evolution of turkey: a plate tectonic approach.tectonophysics, 75, 181-241. şengör, a.m.c., yilmaz, y. & sungurlu, o. (1984): tectonics of the mediterranean cimmerides: nature and evolution of the western termination of palaeo-tethys.in: dixon, j.e. & robertson, a.h.f. (eds.): the geological evolution of the eastern mediterranean. geol. soc. london spec. publ., 17, 77-112, london. stampfli, g.m. (1978): étude géologique générale de l’elburz oriental au sud de gonbad-e-quabus, iran n-e.unpublished phd thesis, university of genève, 328 p. stille, h. (1944a): geotektonische gliederung der erdgeschichte.abh. preuß. akad. wiss. berlin, math.-naturwiss. kl., jg. 1944/3, 5-8, berlin. stille, h. (1944b): geotektonische probleme des pazifischen erdraumes.abh. preuß. akad. wiss. berlin, math.-naturwiss. kl., jg. 1944/11, 77 p., berlin. stöcklin, j. (1974): possible ancient continental margin in iran.in: burk, c.a. & drake, c.a. (eds.): the geology of continental margins. springer-verlag, 873-887, berlin. stöcklin, j. (1977): structural correlation of the alpine ranges between iran and central asia.mém. h. sér. soc. géol. france, 8, 333-353. terzioğlu, n. & satir, m. (1997): batı karadeniz bölgesi volkanik-plutonik ve metamorfik kayaç ör236 geologia croatica 53/2 neklerinin jeokimyasal analizi ile radiometrik yaş tayini sonuçları ve bölgenin jeotektonik evrimindeki konumları.unpubl. t.p.a.o. report no. 3686, 82 p., ankara. t e r z i oğlu, n. & satir, m. & saka, k. (2000): geochemistry and geochronology of basaltic rocks of the küre basin, central pontides (n-turkey).international earth sciences colloquium of the aegean region, iesca 2000, 25-29 september 2000, izmir, abstracts, 219, izmir. thein, u myint lwin (1970): on the occurrence of d a o n e l l a facies from the upper chindwin area, western burma.union of burma j. sci. & tech,, 1970/3, 277-282. tumanskaya, o.g. (1916): o permo-karbonovych ammonejach kryma.zap. geol., otd. o. ljubitelej estestvoznanija, antropologii i etnografii, 99-111, moscow. tumanskaya, o.g. (1931): pe r m o k a r b o n o v y e otlozhenija kryma. cephalopoda.geological survey, leningrad-moscow, 117 p. tumanskaya, o.g. (1937): gorizonty permi kryma.problemy sov. geol., 1937/5-6, 470-472. tumanskaya, o.g. (1941): k stratigrafii permskych otlozhenij kryma.dokl. an sssr, 32/4, 259-262. tüysüz, o., yi . ği . t b aş, e. & serdar, h.s. (1990): an approach to the early mesozoic evolution of the central pontides: the paleotethys-ka r akaya marginal sea problem.proceedings of the 8th petroleum congress of turkey, 351-361, ankara. uro©evi∆, d. (1988): microfossils from the triassic of the inner belt of the yugoslavian carpathobalkanides.ann. géol. péninsule balkanique, 52, 371-379. ustaömer, t. & robertson, a.h.f. (1995): palaeotethan tectonic evolution of the north tethyan margin in the central pontides, n. turkey.in: erler, a., ercan, t., bingöl, e. & örçen, plate i figs. 1-6 permian olistoliths in the lower part of the upper jurassic beykoz formation, within an olistostrome that contains olistoliths of shallow-water and pelagic permian limestones, partly with reworked upper carboniferous. outcrop dağ mahellesi at kircalla village 11.5 km e of azdavay (locality 4 of text fig. 1). figs. 7-11 sporomorphs from sample no. 1996/56, a middle triassic (? lower anisian) black radiolarite, roadcut at the küre-inebolu road (locality 1 in text fig. 1). fig. 1 bioclastic wackestone or grainstone to wackestone. sample no. 1996/141, x 18.5, roadian (kubergandinian to earliest murgabian fusulinid age). fig. 2 grainstone with sparitic cement and micritic matrix. rich in bioclasts (fusulinids etc., partly incrusted by t u b i p h y t e s and a r c h a e o l i t h o p o r e l l a ). sample no. 1996/151, x 18.5, wordian (early murgabian fusulinid age). fig. 3 bioclastic grainstone with some pelmicritic matrix strongly washed out, mostly sparitic cement, bioclasts partly incrusted. beside the shallow-water bioclasts, small ammonoids are present (one is visible in the figure) that postmortally drifted into this shallow-water environment. the same facies as for ammonoid-bearing olistoliths in the taurida flysch of se crimea. sample no. 1996/140, x 18.5, guadalupian. fig. 4 rudstone, matrix micritic, components wackestone, mudstones, reworked shallow and basinal rocks. sample no. 1996/148, x 18.5, wordian (murgabian to early midian fusulinid age) with reworked upper carboniferous (gzhelian) conodonts. fig. 5 bioclastic, bioturbated mudstone, few biogenic clasts. sample no. 1996/146, x 18.5, upper carboniferous to permian. fig. 6 bioclastic bioturbated mudstone. sample no. 1996/144, x 18.5, upper carboniferous to permian. fig. 7 striatoabieites balmei klaus, broken specimen, x 850. fig. 8 platysaccus leschiki hart, x 425. figs. 9, 10 triadispora epigona klaus, x 930. fig. 11 triadispora sp., x 795. 237kozur et al. plate i 238 geologia croatica 53/2 s. (eds.): geology of the black sea region, general dir. of min. res. and expl. & chamb. of geol eng., 24-32, ankara. ustaömer, t. & robertson, a.h.f. (1997):tectonic-sedimentary evolution of the north tethyan margin in the central pontides of northern turkey.in: robinson, a.g. (ed.): regional and petroleum geology of the black sea and surrounding region.aapg memoir, 68, 255-290. ustaömer t. & robertson, a.h.f. (1999): geochemical evidence used to test alternative plate tectonic models for pre-upper jurassic (palaeoteplate ii microfossils from thin-sections of permian olistoliths in the lower part of the upper jurassic beykoz formation, within an olistostrome that contains olistoliths of shallow-water and pelagic permian limestones, partly with reworked upper carboniferous faunas. outcrop dağ mahellesi at kircalla village 11.5 km e of azdavay (locality 4 of text fig. 1). fig. 1 nankinella ? sp. sample no. 1996/143, x 38, capitanian (midian fusulinid age). fig. 2 staffella sp. sample no. 1996/141, x 38, roadian (kubergandinian to earliest murgabian fusulinid age). fig. 3 bultoniinae (fusulinid), gen. et spec. indet. sample no. 1996/143, x 78, capitanian (midian fusulinid age). fig. 4 afghanella sp. sample no. 1996/150, x 18.5, guadalupian. fig. 5 n e o s c h w a g e r i n a s i m p l e x ozawa. sample no. 1996/152, x 38, wordian (early murgabian fusulinid age). fig. 6 minojapanella sp. sample no. 1996/151, x 19, wordian (early murgabian fusulinid age). fig. 7 parafusulina sp. sample no. 1996/150, x 18.5, guadalupian. fig. 8 lasiotrochus tatoiensis reichel. sample no. 1996/143, x 75, capitanian (midian fusulinid age). fig. 9 dagmarita chanakchensis reichel. sample no. 1996/143, x 38, capitanian (midian fusulinid age). fig. 10 neoendothyra parva (lange). sample no. 1996/142, x 38, guadalupian. fig. 11 globivalvulina sp. sample no. 1996/143, x 38, capitanian (midian fusulinid age). fig. 12 palaeotextularia sp. sample no. 1996/153, x 38, guadalupian. fig. 13 deckerella sp. sample no. 1996/143, x 78, capitanian (midian fusulinid age). fig. 14 palaeotextulariid indet. sample no. 1996/151, x 18.5, wordian (early murgabian fusulinid age). fig. 15 pachyphloia ovata lange. sample no. 1996/149, x 78, guadalupian. fig. 16 geinitzina postcarbonica spandel. sample no. 1996/152, x 38, wordian (early murgabian fusulinid age). fig. 17 geinitzina reperta bykova. sample no. 1996/143, x 53.5, capitanian (midian fusulinid age). fig. 18 nodosaria postgeinitzi efimova. sample no. 1996/146, x 77, upper carboniferous to permian. fig. 19 tuberitina collosareitlinger. sample no. 1996/153, x 77, guadalupian. fig. 20 t u b e r i t i n a c o n i l i nguyen. sample no. 1996/141, x 76, roadian (kubergandinian to earliest murgabian fusulinid age). fig. 21 eotuberitina reitlingerae miklucho-maklay. sample no. 1996/146, x 154, upper carboniferous to permian. fig. 22 mizzia sp. sample no. 1996/151, x 18, wordian (early murgabian fusulinid age). fig. 23 pseudovermiporella nipponica (endo). sample no. 1996/141, x 78, roadian (kubergandinian to earliest murgabian fusulinid age). fig. 24 tubiphytes obscurus maslov. sample no. 1996/151, x 19, wordian (early murgabian fusulinid age). fig. 25 tubiphytes carinthiacus (flügel). sample no. 1996/142, x 19, guadalupian. fig. 26 archaeolithoporella sp. sample no. 1996/150, x 18.5, guadalupian. 239kozur et al. plate ii ~ . '4 • • , ..... ~-.: • ,to .~ . 240 geologia croatica 53/2 thyan) units in the central pontides, n turkey.geol. j., 34, 25-53. yi . ği . t b aş, e., elmas, a. & yilmaz, y. (1999): pre-cenozoic tectono-stratigraphic components of the western pontides and their geological evolution.geol. j., 34, 55-74. yilmaz, o. (1981): petrography and whole-rock chemistry of the ebrek metamorphite (daday-devrekani massif, western pontides, turkey).yerbilimleri, 8, 71-82. yilmaz, y. & tüysüz. o. (1988): an approach to the problem of reconstructing the mesozoic units in the kargı massif and its surroundings.turk. assoc. petrol. geol., 1, 73-86, ankara. yilmaz, y., tüysüz. o., yi . ği . t b aş, e., genç, ş.c. & şengör, a.m.c. (1997): geology and tectonic evolution of the pontides.in: robinson, a.g. (ed.): regional and petroleum geology of the black sea and surrounding region. aapg memoir, 68, 183-226. webby, b.d. (1967): tube fossils from the triassic of south-west wellington, n.z.trans. roy. soc. new zealand, 5/7, 181-191. zaninetti, l., ciarapica, g., martini, r. & rettori, r. (1987): t u r r i g l o m i n a s c a n d o n e i, n. sp., dans les calcaires recifeaux du trias moyen (ladinien) en apennin meridional.rev. paléobiol., 6/2, 177-182. zaninetti, l., rettori, r. & martini, r. (1994): aulotortus ? eotriasicus , un nuove foraminifero del trias medio (anisico) delle dinaridi ed ellenidi.boll. soc. paleont. italiana, 33/1, 43-49. manuscript received august 30, 1999. revised manuscript accepted november 13, 2000. plate iii figs. 1-3, 5, 6 different microfacies from middle triassic olistoliths in the middle to upper carnian part (turbidites and olistostromes) of the akgöl group (karadağtepe formation). outcrop at the inebolu küre road south of inebolu (locality 1 of text fig. 1). all magnifications x 27. fig. 4 permian olistolith in the lower part of the upper jurassic beykoz formation within an olistostrome that contains olistoliths of shallow-water and pelagic permian limestones, partly with reworked upper carboniferous faunas. outcrop dağ mahellesi at kircalla village 11.5 km e of azdavay (locality 4 of text fig. 1). magnification x 6.7. fig. 1 bioclastic mudstone (radiolarian biomicrite) with radiolarians, ostracods and filaments. sample no. 1996/48, (middle or) upper anisian. fig. 2 filamentous packstone, extremely rich in filaments. sample no. 1996/49, lower pelsonian upper paragondolella bulgarica zone. fig. 3 filamentous biomicrite with abundant filaments and few ostracods. sample no. 1996/50, pelsonian to lower illyrian. fig. 4 bioclastic grainstone with little pelmicritic matrix, mostly sparitic cement, shallow-water bioclasts, but also a small ammonoid shell. ammonoids probably did not live in this facies, thus the shell is probably postmortally drifted. the same facies as for ammonoid-bearing olistoliths in the taurida flysch of se crimea. sample no. 1996/140, roadian (kubergandinian to earliest murgabian fusulinid age). fig. 5 clast of filamentous, radiolarian bearing micrites that is rich in filaments and contain ostracods, foraminifers within nearly fossil-free packstone (not in the picture). sample no. 1996/52, middle-upper anisian. fig. 6 fine-grained wackestone with small bioclasts (filaments) and graded calciturbidite with reworked shallow-water clasts. sample no. 1996/54, illyrian. 241kozur et al. plate iii 242 geologia croatica 53/2 plate iv different microfacies from middle triassic olistoliths in the middle upper carnian part (turbidites and olistostromes) of the akgöl group (karadağtepe formation). outcrop at the inebolu küre road south of inebolu (locality 1 of text fig. 1). all magnifications x 26.5. fig. 1 radiolarian wackestone, bioturbated, with filaments and few foraminifers, ostracods and sponge spicules. sample no. 1996/55, lower anisian (upper aegean) neogondolella ? regalis zone. fig. 2 radiolarian-rich lydite, with few sporomorphs (see pl. 1, figs. 7-11). sample no. 1996/56, lower anisian. fig. 3 bioclastic grainstone. sample no. 1996/57, anisian. fig 4 bioclastic wackestone and mudstone with numerous filaments, ostracods, few radiolarians. sample no. 1996/62, lowermost anisian chiosella timorensis zone. fig. 5 bioclastic wackestone, bioturbated, partly packstone, filaments, ostracods and (not in the picture) crinoids, echinid spines and few radiolarians. sample no. 1996/63, upper anisian. fig. 6 shallow-water, dasycladacean algae limestone (bioclastic grainstone with mainly sparitic cement) with dasycladacean algae and echinoderm remains. sample no. 1996/65, anisian. 243kozur et al. plate iv 244 geologia croatica 53/2 plate v figs. 1-11 thin sections with microfossils from anisian olistoliths in the middle upper carnian part (turbidites and olistostromes) of the akgöl group (karadağtepe formation). outcrop at the inebolu küre road south of inebolu (locality 1 of text fig. 1). figs. 12, 13 outcrop of werfen beds, “gutenstein” limestone and steinalm dolomite at the road between the villages of aha and sırçalık (locality 3 of text fig. 1). fig. 1 ammobaculitessp. sample no. 1996/62, x 72, lowermost anisian chiosella timorensis zone. fig. 2 nodosaria ordinata trifonova. sample no. 1996/62, x 103, lowermost anisian chiosella timoren sis zone. fig. 3 tolypammina aff. t. gregaria wendt. sample no. 1996/62, x 51.5, lowermost anisian chiosella tim orensis zone. fig. 4 cross section of a leiostrace ammonoid. sample no. 1996/62, x 25.75, lowermost anisian c h i o s e l l a timorensis zone. fig. 5 m e a n d r o s p i r a p u s i l l a (ho). sample no. 1996/64, x 206, upper olenekian limestone clasts within an illyrian pelagic limestone olistolith. fig. 6 involutinidae, gen. et spec. indet. sample no. 1996/65, x 103, anisian. fig. 7 trochammina sp. or duostominidae. sample no. 1996/65, x 103, anisian. fig. 8 hoyenella gr. sinensis (ho). sample no. 1996/65, x 51.5, anisian. fig. 9 hoyenella ? sp. sample no. 1996/65, x 51.5, anisian. fig. 10 hoyenella sp. sample no. 1996/65, x 103, anisian. fig. 11 dasycladacean algae. sample no. 1996/65, x 18, anisian. fig. 12 spirorbis phlyctaena brönnimann & zaninetti. sample no. 1996/95, x 51.5, yellowish weathered, marly, shallow-water werfen limestone (formerly regarded as d a o n e l l a-bearing, pelagic ladinian limestone), olenekian (upper scythian). fig. 13 spirorbis phlyctaena brönnimann & zaninetti. sample no. 1996/99, x 51.5, yellowish weathered, marly, shallow-water werfen limestone (formerly regarded as d a o n e l l a-bearing, pelagic ladinian limestone), olenekian (upper scythian). 245kozur et al. plate v 246 geologia croatica 53/2 plate vi thin-sections with microfossils from anisian olistoliths in the middle-upper carnian part (turbidites and olistostromes) of the akgöl group (karadağtepe formation). outcrop at the inebolu küre road south of inebolu (locality 1 of text fig. 1). fig. 1 a r e n o v i d a l i n a sp. sample no. 1996/55, x 105, lower anisian (upper aegean) n e o g o n d o l e l l a ? r e g a l i s zone. fig. 2 spirobis valvata (goldfuss). sample no. 1996/57, x 52.5, anisian. fig. 3 dasycladacean cross section. sample no. 1996/57, x 26.25, anisian. fig. 4 earlandia cf. tintinniformis (mí©ik). sample no. 1996/57, x 105, anisian. fig. 5 pilammina cf. densa panti∆. sample no. 1996/57, x 52.5, anisian. fig. 6 hoyenella sp. sample no. 1996/57, x 105, anisian. fig. 7 hoyenella gr. sinensis (ho). sample no. 1996/57, x 52.5, anisian. fig. 8 hoyenella sp. sample no. 1996/57, x 52.5, anisian. fig. 9 pilammina cf. densa panti∆. sample no. 1996/59, x 105, middle-upper anisian. fig. 10 hoyenella gr. sinensis (ho). sample no. 1996/59, x 52.5, middle-upper anisian. fig. 11 hoyenella gr. sinensis (ho). sample no. 1996/59, x 52.5, middle-upper anisian. fig. 12 glomospirella sp. sample no. 1996/59, x 52.5, middle-upper anisian. fig. 13 m e a n d r o s p i r a d i n a r i c a (kochansky-dévidé & panti∆). sample no. 1996/59, x 105, middleupper anisian. fig. 14 glomospira sp. sample no. 1996/59, x 105, middle-upper anisian. fig. 15 glomospira sp. sample no. 1996/59, x 52.5, middle-upper anisian. fig. 16 aulotortus ? eotriassicus zaninetti, rettori & martini. sample no. 1996/59, x 52.5, middleupper anisian. fig. 17 ? aulotortus ? eotriassicus zaninetti, rettori & martini. sample no. 1996/59, x 105, middleupper anisian. 247kozur et al. plate vi .. .• 16 248 geologia croatica 53/2 plate vii thin-sections with microfossils from anisian olistoliths in the middle-upper carnian part (turbidites and olistostromes) of the akgöl group (karadağtepe formation). outcrop at the inebolu küre road south of inebolu (locality 1 of text fig. 1). fig. 1-4 hoyenella gr. sinensis (ho). sample no. 1996/60, x 100, anisian. fig. 5 hoyenella sp. sample no. 1996/60, x 100, bithynian-pelsonian. fig. 6 hoyenella gr. sinensis (ho). sample no. 1996/60, x 100, bithynian-pelsonian. figs. 7-8 hoyenella sp. sample no. 1996/60, x 100, bithynian-pelsonian. fig. 9 indet. foraminifer. sample no. 1996/60, x 100, bithynian-pelsonian. fig. 10 meandrospiranella samueli salaj. sample no. 1996/60, x 100, bithynian-pelsonian. fig. 11 meandrospira dieneri (kristan-tollmann). sample no. 1996/60, x 50, bithynian-pelsonian. fig. 12 m e a n d r o s p i r a d i e n e r i (kristan-tollmann). sample no. 1996/62, x 200, lowermost anisian (lower aegean) chiosella timorensis zone. fig. 13 m e a n d r o s p i r a d i e n e r i (kristan-tollmann). sample no. 1996/62, x 100, lowermost anisian (lower aegean) chiosella timorensis zone. fig. 14 trochammina sp. sample no. 1996/62, x 100, lowermost anisian (lower aegean) chiosella timorensis zone. fig. 15 e a r l a n d i a g r a c i l i s zaninetti. sample no. 1996/62, x 50, lowermost anisian (lower aegean) chiosella timorensis zone. 249kozur et al. plate vii 250 geologia croatica 53/2 plate viii conodonts and placoid scale from the lowermost anisian (lower aegean) c h i o s e l l a t i m o r e n s i s zone. sample no. 1996/62. olistolith of grey, bioclastic wackestone and mudstone (with numerous filaments, mostly from ostracods) in the middle upper carnian part (turbidites and olistostromes) of the akgöl group (karadağtepe formation). outcrop at the inebolu küre road south of inebolu (locality 1 of text fig. 1). figs. 1, 2 chiosella timorensis (nogami), pa element, lateral view, x 100; fig. 1: rep.-no. 1996/22-11-i/5; fig. 2: rep.-no. 1996/22-11-i/2. figs. 3, 4 c h i o s e l l a g o n d o l e l l o i d e s (bender), pa element, lateral view; fig. 3: x 100, rep.-no. 1996/22-11-i/3; fig. 4: x 147, rep.-no. 1996/22-11-i/22. figs. 5, 12 g l a d i g o n d o l e l l a sp., ramiform elements, x 100, fig. 5: m element, rep.-no. 1996/22-11-i/16; fig. 12: broken part of sb element, rep.-no. 1996/22-11-i/29. figs. 6-10 c h i o s e l l a sp., ramiform elements; fig. 6: pb element, x 100, rep.-no. 1996/22-11-i/6; fig. 7: sa element, x 200, rep.-no. 1996/22-11-i/12; fig. 8: sb element, rep.-no. 1996/22-11-i/23; fig. 9: sa element, x 200, rep.-no. 1996/22-11-i/18; fig. 10: broken posterior bar of sa element, x 79, rep.-no. 1996/22-11-i/13. fig. 11 placoid scale, x 100, rep.-no. 1996/22-11-i/10. 251kozur et al. plate viii 252 geologia croatica 53/2 plate ix microfossils from the lowermost anisian (lower aegean) c h i o s e l l a t i m o r e n s i s zone. sample no. 1996/62. olistolith of grey, bioclastic wackestone and mudstone (with numerous filaments, mostly from ostracods) in the middle upper carnian part (turbidites and olistostromes) of the akgöl group (karadağtepe formation). outcrop at the inebolu küre road south of inebolu (locality 1 of text fig. 1). figs. 1-4 fish remains; fig. 1: ganoid scale, x 100, rep.-no. 1996/22-11-i/31; fig. 2: acrodus sp., x 142, rep.-no. 1996/22-11-i/27; fig. 3: placoid scale, x 84, rep.-no. 1996/22-11-i/11; fig. 4: s a u r i c h t h y s sp., x 100, rep.-no. 1996/22-11-i/14. figs. 5-7 holothurian sclerites; fig. 5. t h e e l i a i m m i s o r b i c u l a mostler, x 200, rep.-no. 1996/22-11-ii/1; fig. 6: eocaudina sp., x 294, rep.-no. 1996/22-11-i/24; fig. 7: priscopedatus triassicus mostler, x 294, rep.-no. 1996/22-11-i/8. fig. 8 gastropod steinkern, x 200, rep.-no. 1996/22-11-i/26. fig. 9 spinocypris nepalensis kozur, x 200, rep.-no. 1996/22-11-i/20. 253kozur et al. plate ix 254 geologia croatica 53/2 plate x figs 1-9 microfossils (fig. 1: foraminifera; figs. 2-3: echinodermata; figs. 4-9: conodonta) from anisian limestone olistoliths in the middle upper carnian part (turbidites and olistostromes) of the akgöl group (karadağt e p e formation). outcrop at the inebolu küre road south of inebolu (locality 1 of text fig. 1). fig. 10 bathypelagic ostracod from an olistolith of a dark-grey upper carboniferous to permian bioclastic, bioturbated mudstone with some biogenic clasts, within the lower part of the upper jurassic beykoz formation (locality 4 of text fig. 1). fig. 1 tolypammina sp. sample no. 1996/62 (see plates vii, viii), x 78, rep.-no. 1996/22-11-i/15. figs. 2, 3 a s p i d o c r i n i t e s n.sp., lower view, sample no. 1996/62 (see plates vii, viii); fig. 2: x 244, rep.-no. 1996/22-11-i/30; fig. 3: x 99, rep.-no. 1996/22-11-i/21. figs. 4, 5 neogondolella ? regalis mosher, pa element, lateral view. sample no. 1996/55, x 99, lower anisian (upper aegean) n. ? r e g a l i s zone, olistolith of grey radiolarian wackestone (bioturbate, with foraminifers, ostracods, sponge spicules, filaments); fig. 4: rep.-no. 1996/22-11-ii/75; fig. 5: rep.-no. 1996/22-11-ii/81. figs. 6, 7, 9 g l a d i g o n d o l e l l a b u d u r o v i kovács & kozur. sample no. 1996/5o, x 99, bithynian or pelsonian, olistolith of grey, filamentous biomicrite (with very much filaments, few foraminifers, some ostracods); fig. 6: pa element, upper view, rep.-no. 1996/22-11-ii/41a, fig. 7: posterior bar of sc element, rep.-no. 1996/22-11-ii/42; fig. 9: pb element, rep.-no. 1996/22-11-ii/44. fig. 8 paragondolella bulgarica budurov & stefanov, pa element, lateral view, juvenile form, x 197, rep.-no. 1996/22-11-ii/39, sample no. 1996/60, bithynian or pelsonian, olistolith of a grey grainstone. fig. 10 permocypridina mocki n.gen. n.sp., rv, lateral view. sample no. 1996/146, x 83. 255kozur et al. plate x 256 geologia croatica 53/2 plate xi conodonts from the pelsonian upper paragondolella bulgarica zone. sample no. 1996/49. olistolith of a grey filamentous packstone, extremely rich in filaments, in the middle upper carnian part (turbidites and olistostromes) of the akgöl group (karadağtepe formation). outcrop at the inebolu küre road south of inebolu (locality 1 of text fig. 1). figs. 1-7 paragondolella bulgarica budurov & stefanov, pa element; fig. 1: lateral view, x 99, rep.-no. 1996/22-11-ii/31; fig. 2: upper view, x 146, rep.-no. 1996/22-11-ii/17; fig. 3: lateral view, x 146, rep.no. 1996/22-11-i/62; fig. 4: transitional form to paragondolella shoshonensis nicora, upper view, x 99, rep.-no. 1996/22-11-ii/8; fig. 5: upper view, x 146, rep.-no. 1996/22-11-ii/10; fig. 6: lateral view, x 99, rep.-no. 1996/22-11-ii/7; fig. 7: lateral view, x 146, rep.-no. 1996/22-11-ii/20. figs. 8, 11, 12 paragondolella bulgarica budurov & stefanov, ramiform elements; fig. 8: pb element, x 99, rep.-no. 1996/22-11-i/55; fig. 11: sb element, x 99, rep.-no. 1996/22-11-ii/34; fig. 12: sa element, x 198, rep.-no. 1996/22-11-i/54. fig. 9 p a r a g o n d o l e l l a b i f u r c a t a budurov & stefanov, pa element, upper view, x 99, rep.-no. 1996/22-11-i/64. fig. 10 neohindeodella dropla (spasov & ganev), x 198, rep.-no. 1996/22-11-ii/22. fig. 13 neohindeodella aequiramosa kozur & mostler, x 146, rep.-no. 1996/22-11-i/66. 257kozur et al. plate xi 258 geologia croatica 53/2 plate xii conodonts and palaeopsychrosphaeric ostracods from the pelsonian upper paragondolella bulgarica zone. sample no. 1996/49. olistolith of a grey filamentous packstone, extremely rich in filaments, in the middle upper carnian part (turbidites and olistostromes) of the akgöl group (karadağtepe formation). outcrop at the inebolu küre road south of inebolu (locality 1 of text fig. 1). figs. 1-5 g l a d i g o n d o l e l l a t e t h y d i s (huckriede); fig 1: pa element, juvenile specimen, lateral view, x 200, rep.-no. 1996/22-11-i/52; fig. 2: sb element, x 100, rep.-no. 1996/22-11-i/39; fig. 3: m element, x 100, rep.-no. 1996/22-11-ii/32; fig. 4. posterior bar of sc element, x 100, rep.-no. 1996/22-11-ii/2; fig. 5: anterior bar of sc element, x 100, rep.-no. 1996/22-11-i/48. fig. 6 spinocypris vulgaris kozur, rv, lateral view, x 147, rep.-no. 1996/22-11-ii/4. fig. 7 acratina goemoeryi (kozur), right lateral view, x 100, rep.-no. 1996/22-11-i/35. fig. 8 triassocythere sp., lv, lateral view, x 100, rep.-no. 1996/22-11-ii/25. fig. 9 acratina triassica kozur, lv, lateral view, x 89, rep.-no. 1996/22-11-ii/29. fig. 10 polycope sp. 1, lv, lateral view, x 147, rep.-no. 1996/22-11-ii/14. 259kozur et al. plate xii 260 geologia croatica 53/2 plate xiii palaeopsychrosphaeric ostracods and one conodont from olistoliths in the middle upper carnian part (turbidites and olistostromes) of the akgöl group (karadağtepe formation). outcrop at the inebolu küre road south of inebolu (locality 1 of text fig. 1). figs. 1-9 sample no. 1996/49, pelsonian upper p a r a g o n d o l e l l a b u l g a r i c a zone. olistolith of a grey filamentous packstone, extremely rich in filaments. fig. 10 sample no. 1996/63, olistolith of a grey, bioclastic wackestone, bioturbated, partly packstone, with filaments, ostracods, crinoids, echinid spines and a few radiolarians. illyrian. fig. 1 c r y p t o b a i r d i a a t u d o r e i i (crasquin-soleau & gradinaru), lv, inner view, x 99, rep.-no. 1996/22-11-i/38. fig. 2 polycope sp. 1, rv, lateral view, x 146, rep.-no. 1996/22-11-ii/21. fig. 3 polycope sp. 2, lv, lateral view, x 146, rep.-no. 1996/22-11-ii/25. fig. 4 paraberounella n.sp., identical with the specimen of paraberounella ? renardi crasquin-soleau & gradinaru figured by these authors on pl. 9, fig. 3, rv, lateral view, x 146, rep.-no. 1996/2211-ii/19. fig. 5 polycopsis cincinnata (apostolescu), rv, lateral view, x 146, rep.-no. 1996/22-11-ii/3. figs. 6-8 paraberounella triassica kozur, x 99; fig. 6: rv, lateral view, rep.-no. 1996/22-11-i/49; fig. 7: lv, lateral view, rep.-no. 1996/22-11-ii/13; fig. 8: rv, upper view, rep.-no. 1996/22-11-ii/16. fig. 9 nagyella longispinosa kozur, rv, inner view, x 99, rep.-no. 1996/22-11-ii/11. fig. 10 neogondolella cornuta budurov & stefanov, upper view, x 78, rep.-no. 1996/22-11-i/34. 261kozur et al. plate xiii 262 geologia croatica 53/2 plate xiv figs. 1-10 conodonts and holothurian sclerites from anisian pelagic limestone olistoliths in the middle u p p e r carnian part (turbidites and olistostromes) of the akgöl group (karadağtepe formation). outcrop at the inebolu küre road south of inebolu (locality 1 of text fig. 1). fig. 11 upper carboniferous pelagic conodont. figs. 1-4 g l a d i g o n d o l e l l a sp., ramiform elements, sample no. 1996/51, pelsonian grey, filamentous, partly bioclastic wackestone to packstone, with numerous filaments, common radiolarians, few gastropods, and ophiurian remains; fig. 1: pa element, lateral view, early, platform-free juvenile specimen, x 140, rep.no. 1996/22-11-ii/70; fig. 2: sc element, x 140, rep.-no. 1996/22-11-ii/65; fig. 3: broken part of sb element, x 85, rep.-no. 1996/22-11-ii/66; fig. 4: m element, x 140, rep.-no. 1996/22-11-ii/62. fig. 5 t h e e l i a c o n s o n a (carini), upper view, x 190, sample no. 1996/51 (see figs. 1-4), rep.-no. 1996/2211-ii/59. figs. 6, 7 g l a d i g o n d o l e l l a sp., ramiform elements, sample no. 1996/54, upper illyrian grey, fine-grained wackestone with small bioclasts and graded calciturbidites with reworked shallow-water clasts; fig. 6: sc element, x 120, rep.-no. 1996/22-11-ii/58; fig. 7: broken part of sb lement, x 95, rep.-no. 1996/22-11ii/53. fig. 8 n e o g o n d o l e l l a c o n s t r i c t a (mosher & clark), advanced form, lower view, x 190, sample no. 1996/54 (see figs. 6, 7). figs. 9, 10 n e o g o n d o l e l l a sp., ramiform elements, sample no. 1996/54 (see figs 6, 7); fig. 9: sc element, x 140, rep.-no. 1996/22-11-ii/56; fig. 10: sa element, x 190, rep.-no. 1996/22-11-ii/51. fig. 11 juvenile s t r e p t o g n a t h o d u s sp. ex gr. s. r u z h e n c e v i kozur, oblique upper view, x 200. sample 148, olistolith of a wordian rudstone with reworked shallow-water and basinal rocks that also contain upper carboniferous pelagic conodonts, olistostrome within the upper jurassic beykoz formation. outcrop dağ mahellesi at kircalla village 11.5 km e of azdavay (locality 4 of text fig. 1). 263kozur et al. plate xiv 264 geologia croatica 53/2 plate xv trace fossils and torlessia from upper triassic turbidites of the karadağtepe formation. fig. 1 t o r l e s s i a n.sp., x 0.85, middle to upper carnian turbidites of karadağtepe formation, roadcut at the inebolu küre road, approximately 9 km south of inebolu, rep.-no. ky 98-7. fig. 2 t o r l e s s i a m a c k a y i bather, detail, x 12, lower to middle norian turbidites of karadağtepe formation, sample 377, roadcut at the inebolu -küre road, 10.3 km south of inebolu, rep.-no. ky 98-10 i. fig. 3 chondrites sp. x 12, lower to middle norian turbidites of karadağtepe formation with torlessia mack ayi, sample 377 (see fig. 2), rep.-no. ky 98-21 a. figs. 4, 6 upper triassic new ichnogenus consisting of an elliptical or round ring; fig. 4: x 1.2, lower to middle norian turbidites of karadağtepe formation with t o r l e s s i a m a c k a y i bather, sample 377 (see fig. 2), rep.-no. ky 98-10 d; fig. 6: g o r d i a sp. and the new ichnogenus, x 0.85, middle to upper carnian turbidites of karadağtepe formation with t o r l e s s i a n.sp., roadcut at the inebolu küre road, approximately 9 km south of inebolu, sample 370, rep.-no. ky 98-25 d. fig. 5 phycosiphon incertum fischer-ooster, x 2.15, lower to middle norian turbidites of karadağt e p e formation with torlessia mackayi bather, sample 440, roadcut at the northern entrance to esentepe village, rep.-no. ky 98-27 f. 265kozur et al. plate xv 266 geologia croatica 53/2 appendix: sample data of olistoliths for protolith reconstruction only samples taken in 1996 that are important (stratigraphically or otherwise) to this study are listed. material collected in 1998 is not yet fully processed and only part of the sem study is complete. the most important results from these samples are used in the present paper (e.g. presence of pelsonian to norian hallstatt limestones in the çalça unit) but the fossil data (plates etc.) will be presented later. locality 1 (see text fig. 1) k a r a d ağtepe formation, road inebolu küre, roadcut south of inebolu. if not otherwise indicated, olistoliths within the karadağtepe formation with the middle upper carnian torlessia erenleri n.sp. sample 1996/47 shallow-water limestone (wackestone). fossils: crinoids, foraminifers (h o y e n e l l a sp.). e n v i r o n m e n t : shallow-water shelf. a g e : p r obably anisian. sample 1996/48 bioclastic mudstone (filamentous radiolarian biomicrite). f o ss i l s : conodonts (juvenile p a r a g o n d o l e l l a h a n b u l o g i sudar & budurov, g l a d i g o n d o l e l l a sp., ramiform elements), radiolarians, and ostracods. environment: pelagic. age: (middle) to late anisian. sample 1996/49 filamentous packstone, extremely rich in filaments. fossils: conodonts (p a r a g o n d o l e l l a b u l g a r i c a budurov & stefanov, p . b i f u r c a t a budurov & stefanov, primitive p . s h o s h o n e n s i s, only one specimen, g l a d i g o n d o l e l l a sp., ramiform elements, n e o h i n d e o d e l l a a e q u i r a m o s a kozur & mostler, n. d r o p l a ( s p a s o v & ganev)), ostracods (a c r a t i n a g o e m o e r y i kozur, a. t r i a s s i c a kozur, c a v e l l i n a n. sp., c r y p t o b a i r d i a a t u d o r e i i ( c r a s q u i n soleau & gradinaru), c r y p t o b a i r d i a sp., h u n g a r e l l a r e n i f o r m i s (méhes), n a g y e l l a l o n g i s p i n o s a kozur, p a r a b e r o u n e l l a triassica kozur, paraberounella n.sp. (= paraberounella ? renardi crasquin-soleau & gradinaru, pars), p o l y c o p e sp. 1, p o l y c o p e sp. 2, p o l y c o p s i s c i n c i n n a t a (apostulescu), s p i n o cypris vulgaris kozur, triassocypris sp., triassocythere sp.). envir o n m e n t : pelagic; palaeopsychrosphaeric deep water ostracods indicate full connection to the world ocean and its cold bottom water currents. age: early pelsonian upper paragondolella bulgarica zone. sample 1996/50 filamentous biomicrite with abundant filaments. f o s s i l s : c o nodonts (g l a d i g o n d o l e l l a b u d u r o v i kovács & kozur), foraminifers, holothurian sclerites (t h e e l i a i m m i s o r b i c u l a m o s tler), and ostracods. environment: pelagic. age: middle anisian to lower part of the late anisian. sample 1996/51 filamentous, partly bioclastic wackestone to packstone, with numerous filaments. f o s s i l s : arthropod spines, conodonts (g l a d i g o n dolella sp., ramiform elements and juvenile pa elements), gastropods, holothurian sclerites (t h e e l i a g e r m a n i c a kozur, t. i m m i s o r b i c u l a mostler, t. p l a n a t a mostler, t. c o n s o n a (carini), t e t r a v i r ga levis kozur & mostler), ophiurian remains, and radiolarians. environment: pelagic. age: middle anisian (pelsonian). sample 1996/52 bioclastic packstone, poor in determinable fossils, with clasts of filamentous, radiolarian bearing micrites that are rich in filaments and contain ostracods, foraminifers. fossils: conodonts (g l a d i g o n d o l e l l a sp., ramiform elements and juvenile pa elements), holothurian sclerites (t h e e l i a a n d r u s o v i kozur & mostler, p r i s c o p e d a t u s s p . , t e t r a v i r g a cf. l e v i s kozur & mostler). e n v i r o n m e n t : p e l a g i c . age: early to middle anisian. sample 1996/53 shallow-water boundstone. fossils: bryozoa, calcareous sponges (recrystallized). environment: shallow-water shelf. sample 1996/54 fine-grained wackestone with small bioclasts and graded calciturbidites with reworked shallow-water clasts. fossils: c o n o d o n t s (n e o g o n d o l e l l a c o n s t r i c t a mosher & clark, advanced forms, g l a d i g o n d o l e l l a sp., ramiform elements), foraminifers (n o d o s a r i a sp.), gastropods, holothurian sclerites (t h e e l i a i m m i s o r b i c u l a mostler, t. m u l t i r a d i a t a kozur, t. p l a n a t a mostler, t. u n d a t a mostler, c a l c l a m n a g e r m a n i c a frizzell & exline, tetravirga ? n. sp.), ostracods (microcheilinella sp.), sponge spicules. e n v i r o n m e n t : pelagic calciturbidite. age: late illyrian (latest anisian). sample 1996/55 radiolarian wackestone, bioturbated, with filaments. f o s s i l s : conodonts (gladigondolella sp., ramiform elements, neogondolella ? regalis mosher, fish scales, foraminifers (arenovidalina sp., nodo s a r i a sp.), holothurian sclerites (p r i s c o p e d a t u s n. sp. 1), ostracods (h u n g a r e l l a sp., c r y p t o b a i r d i a sp., p r a e m a c r o c y p r i s sp.). e n v i r o n ment: pelagic. age: early anisian n. ? regalis zone. sample 1996/56 radiolarite (lydite) with numerous radiolarians (low-diversity fauna, all entactinaria and spumellaria) that could not be dissolved from the rock. fossils from the palynological separation : acritarcha indet., bacteria, sporomorphs (a l i s p o r i t e s sp., f a l c i s p o r i t e s s p . , i l l i n i t e s t r i v i s u s visscher, l u n a t i s p o r i t e s sp., p l a t y s a c c u s l e s c h i k i hart, s t r i a t o a b i e i t e s b a l m e i klaus, t r i a d i s p o r a e p i g o n a klaus, triadispora cf. falcata klaus, triadispora sp., few trilete spores). e n v i r o n m e n t : deep water, anoxic to dysaerobic; not too far from the continent; deep, but narrow rift basin, probably restricted connection to the open ocean (abundant, but very low diversity radiolarian fauna). age: middle triassic (? early anisian). sample 1996/57 bioclastic grainstone. fossils: crinoids, dasycladacean algae, echinoderm remains, foraminifers (e a r l a n d i a cf. t i n t i n n i f o r m i s ( m í©ik), h o y e n e l l a gr. s i n e n s i s (ho), h o y e n e l l a sp., p i l a m m i n a d e n s a panti∆), gastropods, ostracods (bairdiacypris sp.), vermes (spiror bis valvata (goldfuss)). environment: shallow-water shelf. age: anisian. sample 1996/59 bioclastic grainstone-wackestone. f o s s i l s : foraminifers (a r e n ovidalina sp., aulotortus ? eotriassicus zaninetti et al., glomospi ra sp., glomospirella sp., hoyenella gr. sinensis (ho), hoyenella sp., m e a n d r o s p i r a d i n a r i c a (kochansky-dévidé & panti∆), p i l a m m i n a d e n s a panti∆), gastropods, ostracods (c r y p t o b a i r d i a s p . ) . environment: shallow-water. age: middle to late anisian. sample 1996/60 grainstone. f o s s i l s : conodonts (p a r a g o n d o l e l l a b u l g a r i c a budurov & stefanov), foraminifers (a m m o d i s c u ssp., h o y e n e l l a gr. s i n e n s i s (ho), h o y e n e l l a sp., m e a n d r o s p i r a d i e n e r i ( k r i stan-tollmann), m e a n d r o s p i r a sp., m e a n d r o s p i r a n e l l a s a m u e l i salaj)), gastropods, vermes (s p i r o r b i s sp.). e n v i r o n m e n t : s h a llow-water, but very near to the shelf edge (paragondolella bulgarica !). age: bithyanian-pelsonian. sample 1996/61a debris flow with silty matrix, and clasts of mafic volcanics, serpentinite detritus, partly brecciated limestones with filaments, indeterminable foraminifers. e n v i r o n m e n t : upper slope deposit. age of matrix: late carnian. 267kozur, aydin, demir, yakar, göncüoğlu & kuru: new stratigraphic and palaeogeographic results... sample 1996/62 bioclastic wackestone and mudstone with numerous filaments, mostly from ostracods. f o s s i l s : ammonoids, conodonts (c h i o s e l l a t i m o r e n s i s (nogami), c h i o s e l l a g o n d o l e l l o i d e s (bender), g l a d i g o n d o l e l l a, ramiform elements), dasycladacean algae, echinoderm remains, among them a s p i d o c r i n i t e s n.sp., fish remains (placoid and other scales, a c r o d u s sp., s a u r i c h t h y s sp.), foraminifers (a m m o b a c u l i t e s sp., e a r l a n d i a g r a c i l i s zaninetti, h o y e n e l l a gr. s i n e n s i s (ho), h o y e n e l l a sp., g l o m o s p i r a sp., m e a n d r o s p i r a d i e n e r i ( k r i stan-tollmann), n o d o s a r i a o r d i n a t a trifonova, p l a n i i n v o l u t a sp., t o l y p a m m i n a a f f. t. g r e g a r i a wendt, t o l y p a m m i n a sp., t r o c h a m m i n a sp.), holothurian sclerites (a c h i s t r u m p u l c h r u m k o z u r , t h e e l i a g e r m a n i c a kozur, t. i m m i s o r b i c u l a mostler, t h e e l i a n.sp., priscopedatus triassicus mostler, eocaudina sp.), ostracods (c r y p t o b a i r d i a sp., m i c r o c h e i l i n e l l a sp., s p i n o c y p r i s n e p a l e n s i s k o z u r ) . environment: upper slope facies. a g e : earliest anisian chiosella timorensis zone. close to scythian-anisian boundary. sample 1996/63 bioclastic wackestone, bioturbated, partly packstone, with filaments. f o s s i l s : conodonts (n e o g o n d o l e l l a c o r n u t a budurov & stefanov), crinoids, echinid spines, foraminifers (glomospira sp., n o d o s a r i a sp., a r e n o v i d a l i n a sp., t o l y p a m m i n a aff. g r e g a r i a wendt), ostracods, few radiolarians. e n v i r o n m e n t : pelagic. a g e : late anisian. sample 1996/64 bioturbated mudstone with a few filaments, some echinoderm remains and sparse radiolarians; some shallow-water limestone clasts with m e a n d r o s p i r a p u s i l l a (ho). fossils from the matrix: c o nodonts (n e o g o n d o l e l l a c o n s t r i c t a (mosher & clark)), foraminifers (e a r l a n d i a sp., g l o m o s p i r a ? sp.). fossils from the shallowwater clasts: foraminifers (m e a n d r o s p i r a p u s i l l a (ho)). e n v i r o n m e n t : slope deposit. age of the matrix: late illyrian (latest). age of the clasts: late olenekian. sample 1996/65 dasycladacean algal limestone, some oncoids, ostracods. fossils: dasycladacean algae, echinid spines, foraminifers (e n d o t h y r a ? sp., g l o m o s p i r a sp., hoyenella g r . s i n e n s i s ( h o ) , h o y e n e l l a sp., t r o c h a m m i n a sp., involutinidae, gen. et spec. indet.), gastropods. e n v i ronment: shallow-water outer shelf. age: anisian. sample 1996/66 siliciclastic turbiditic siltstone, clayey limestone, disturbed (slumping), organic matter, sand grain-sized mafic volcanic clasts. matrix of the olistostrome. e n v i r o n m e n t : lower slope at the active margin of an ocean. age: middle to late carnian. sample 1996/67 turbiditic siltstone with sand grain-sized mafic volcanic clasts, few coaly remnants. matrix of the olistostrome. environment: lower slope at the active margin of an ocean. age: middle to late carnian. sample 1996/68 debris flow with clasts of mafic volcanics (spilitic basalts), very sparce ultramafic detritus, hyaloclastics, and shallow-water limestones, dolomites, partly with oncoids, pelagic limestones, few radiolarites. e n v i r o n m e n t : steep slope at the active margin of an ocean. a g e : as the block lies in a middle late carnian matrix, the volcanics must be of pre-middle carnian age. some of the radiolarites (lydites) are of (early) anisian age (see sample 1996/56). locality 3 (see text fig. 1) outcrops along the road between the villages of aha and sırçalık, sırçalık group, flaser-bedded marly limestone with “d a o n e l l a” (the “d a o n e l l a ” material could not be re-studied, but in the same beds dr. aydin found a badly preserved similar bivalve, probably an e u m o r p h o t i s), formerly assigned to the ladinian, but typical werfen shallow-water facies. age: scythian. sample 1996/91 fossils: vermes (s p i r o r b i s ? sp.). e n v i r o n m e n t : s h a l l o w w a t e r , variable salt content. sample 1996/93 fossils: ostracods, vermes (spirorbis ? sp.). environment: shallow-water, variable salt content. sample 1996/95 fossils: ostracods (filaments), vermes (s p i r o r b i s p h l y c t a e n a brönnimann & zaninetti). e n v i r o n m e n t : s h a l l o w w a t e r , variable salt content. sample 1996/99 fossils: ostracods (filaments), vermes (s p i r o r b i s p h l y c t a e n a brönnimann & zaninetti). e n v i r o n m e n t : s h a l l o w w a t e r , variable salt content. locality 4 (see text fig. 1) se of the azdavay village. beykoz formation with olistoliths of shallow-water and pelagic, mostly middle permian, partly upper carboniferous and lower permian limestones. all listed samples are olistoliths. sample 1996/140 bioclastic grainstone with some pelmicritic matrix, strongly washed out, mostly sparitic cement, bioclasts partly incrusted. f o ssils: algae (archaeolithoporella sp., mizziasp., tubiphytescarinthia c u s (flügel)), ammonoids (!), brachiopods, bryozoans, foraminifers (d i p l o s p h a e r i n a sp., g l o b i v a l v u l i n a v o n d e r s c h m i t t i r e i c h e l , geinitzinidae, palaeotextulariidae indet., p a r a f u s u l i n a ? sp.), gastropods, ostracods. environment: shelf edge; shallow-water, but with drifted small ammonoid shells. a g e : late cisuralian to lower guadalupian. sample 1996/141 bioclastic wackestone or grainstone to wackestone. f o s s i l s : algae (a r c h a e o l i t h o p o r e l l a sp., p s e u d o v e r m i p o r e l l a n i p p o n i c a ( e ndo), t u b i p h y t e s sp.), brachiopods, bryozoans, calcareous sponges, foraminifers (c l i m a c a m m i n a sp., d i p l o s p h a e r i n a i n a e q u a l i s ( d e rville), g l o b i v a l v u l i n a sp., l a n g e l l a sp. or p s e u d o l a n g e l l a s p . , p a c h y p h l o i a sp., t o l y p a m m i n a sp., t u b e r i t i n a b u l b a c e a g a l l oway & harlton, t u b e r i t i n a c o n i l i nguyen, geinitzinidae indet., staffella sp.), gastropods. e n v i r o n m e n t : shallow-water open shelf. age: permian. sample 1996/142 bioclastic wackestone to boundstone, micritic to pelmicritic matrix. fossils: algae (a r c h a e o l i t h o p o r e l l a sp., t u b i p h y t e s c a r i n t h i a c u s (flügel), t. o b s c u r u s maslov), brachiopods, bryozoans, echinoderm remains, foraminifers (n e o n d o t h y r a p a r v a ( l a n g e ) , t e t r a t a x i s sp., geinitzinidae gen. et spec. indet., palaeotextulariidae indet., broken walls of fusulinids). e n v i r o n m e n t : open shallowwater shelf. age: guadalupian. sample 1996/143 fine-grained packstone, slightly washed out, sparitic cement and micritic matrix. fossils: algae (t u b i p h y t e s o b s c u r u s m a s l o v , dasycladacean algae), brachiopods, byozoans, echinoderm remains, foraminifers (d a g m a r i t a c h a n a k c h e n s i s reitlinger, d e c k e r e l l a sp., d i p l o s p h a e r i n a i n a e q u a l i s (derville), e n d o t h y r a sp., g l o b i v a l v u l i n a sp., l a s i o d i s c u s sp., l a s i o t r o c h u s t a t o e n s i s r e i c h e l , n e o e n d o t h y r a sp., p a c h y p h l o i a sp., geinitzina reperta b y k o v a , rectostipulina sp., spiroplectammina sp., tolypammina sp., tuberiti n a b u l b a c e a galloway & harlton, geinitzinidae indet., m i n o j a p a n e l l a sp., n a n k i n e l l a ? sp., boultoniidae gen. et spec. indet.), ostracods (a m p h i s s i t e s sp.), microproblematica, porotubida (p o l y p o r o t u b u s sp.). e n v i r o n m e n t : open shallow-water shelf. a g e : capitanian (d a g m a r i t a c h a n a k c h e n s i s is not present below the capitanian, some of the fusulinids do not occur above the capitanian). 268 geologia croatica 53/2 sample 1996/144 bioclastic bioturbated mudstone. fossils: foraminifers (d i p l o s p h a e r i n a i n a e q u a l i s (derville), geinitzinidae indet.), ostracods (exclusively myodocopida, e.g., p e r m o c y p r i d i n a m o c k i n.gen. n.s p . , and cladocopida, e.g. p o l y c o p e cf. p r o v e c t a zhang). e n v i r o n ment: pelagic limestone. a g e : late carboniferous to middle permian. sample 1996/145 rudstone with shallow-water clasts. fossils: bryozoa, calcareous sponges, corals, foraminifers (t e t r a t a x i s sp., broken walls of schwagerinid fusulinids). e n v i r o n m e n t : shelf edge. a g e : e a r l y m i d d l e permian. sample 1996/146 bioclastic, bioturbated mudstone, few biogenic clasts. f o s s i l s : algae (tubiphytes obscurus maslov), echinoderm remains, forami nifers (d i p l o s p h a e r i n a i n a e q u a l i s (derville), f r o n d i n o d o s a r i a sp.), pelagic ostracods (exclusively myodocopida). e n v i r o n m e n t : pelagic. age: late carboniferous to permian. sample 1996/147 boundstone to wackestone. fossils: algae (t u b i p h y t e s c a r i n t h i a c u s (flügel), t u b i p h y t e s o b s c u r u s maslov, dasycladacean algae), bryozoans, calcareous sponges, corals, echinoderm remains, foraminifers (c l i m a c a m m i n a sp., t o l y p a m m i n a sp., t u b e r i t i n a b u l b a c e a galloway & harlton), gastropods, ostracods. e n v i ronment: open shallow-water shelf. age: guadalupian (?). sample 1996/148 rudstone, matrix micritic, components wackestone, mudstones, reworked shallow and basinal rocks. fossils: algae (t u b i p h y t e s o b s curus maslov), bryozoans, conodonts (reworked juvenile streptog nathodus ex gr. s. ruzhencevi kozur), echinoderm remains, foraminifers (diplosphaerina sp., globivalvulina sp., lunucammina sp., pa c h y p h l o i a sp., t o l y p a m m i n a sp., n e o s c h w a g e r i n a fragment), gastropods, ostracods (partly pelagic forms). environment: proximal slope (pelagic with transported shallow-water fossils, mostly broken, reworked older material). a g e : wordian (murgabian to early midian fusulinid age) with reworked late carboniferous (gzhelian) conodonts. sample 1996/149 packstone with bioand lithoclasts, some siliciclastic material (quartz). fossils: bryozoans, echinoderms, foraminifers (d i p l o s p h a e r i n a i n a e q u a l i s (derville), g l o b i v a l v u l i n a sp., l u n u c a m m i n a s p . , p a c h y p h l o i a o v a t a lange, t u b e r i t i n a b u l b a c e a galloway & harlton, palaeotextulariidae gen. et spec. indet., schubertellidae gen. et spec. indet.), ostracods. e n v i r o n m e n t : slope to shelf. a g e : guadalupian. sample 1996/150 rudstone, with components of boundstones and wackestones, a r c h a e o l i t h o p o r e l l a -t u b i p h y t e s boundstone. fossils: algae (a r c h a e o l i t h o p o r e l l a sp., t u b i p h y t e s sp., dasycladacean algae), bryozoans, calcareous sponges, incrusted by tubiphytes and archaeolithoporella, corals, foraminifers (d i p l o s p h a e r i n a sp., l u n u c a m m i n a sp., p a c h y p h l o i a sp., p a l a e o t e x t u l a r i a sp., p r o t o n o d o s a r i a sp., p s e u d o l a n g e l l a sp., parafusulina sp., afghanella sp.), ostracods. environment: open shallow-water shelf. age: guadalupian. sample 1996/151 grainstone with sparitic cement and micritic matrix. f o s s i l s : algae (m i z z i a sp., p s e u d o v e r m i p o r e l l a n i p p o n i c a (endo), t u b i p h y t e s c a r i n t h i a c u s (flügel), t. o b s c u r u s maslov), brachiopods, bryozoans, calcareous sponges, corals, foraminifers (b a i s a l i n a ? sp., t e t r a t a x i s sp., t o l y p a m m i n a sp., geinitzinidae, gen. et spec. indet., palaeotextulariidae gen. et spec. indet., c a n c e l l i n a ? sp., c h u senella sp., minojapanella sp., nankinella sp., primitive neoschwage r i n a sp.), gastropods. e n v i r o n m e n t : open shallow-water shelf. a g e : wordian (early murgabian fusulinid age). sample 1996/152 rudstone, angular components of wackestones, mudstones, boundstones in micritic matrix. fossils: algae (a r c h a e o l i t h o p o r e l l a sp., t u b i p h y t e s o b s c u r u s maslov), bivalve fragments, bryozoans, corals, echinoderm remains, foraminifers (d i p l o s p h a e r i n a sp., g e i n i tzina postcarbonica spandel, primitive n e o e n d o t h y r a , m i n o j a p a n e l l a ? sp., n e o s c h w a g e r i n a s i m p l e x ozawa), microproblematica. e n v i r o n m e n t : upper slope deposit. a g e : wordian (early murgabian fusulinid age). sample 1996/153 bioclastic, bioturbated wackestone, fine-grained with few large biogenic remnants. f o s s i l s : algae (a r c h a e o l i t h o p o r e l l a s p . , t u b i p h y tesobscurus maslov), bryozoans, calcareous sponges, corals, echinoderm remains, foraminifers (l a s i o d i s c u s sp., p a c h y p h l o i a s p . , p a l a e o t e x t u l a r i a sp., t u b e r i t i n a c o l l o s a reitlinger, geinitzinidae, gen. et spec. indet.), gastropods, ostracods. e n v i r o n m e n t : s h e l f edge. age: guadalupian. sample 1996/154 pelagic mudstone with large shallow-water limestone clasts (grainstone, boundstone). fossils: algae (a r c h a e o l i t h o p o r e l l a s p . , m i z z i a sp., t u b i p h y t e s o b s c u r u s maslov, s t a c h e o i d e s sp. (red algae)), brachiopods, bryozoans, calcareous sponges, incrusted by a r c h a e o l i t h o p o r e l l a and t u b i p h y t e s, corals, echinoderm remains, foraminifers (diplosphaerina sp., pachyphloia sp., neoschwagerina ? sp.), ostracods (shallow-water and pelagic forms). e n v i r o n m e n t : slope deposits (probably reef slope). age: wordian (murgabian to early midian fusulinid age). sample 1996/155 pelagic bioclastic mudstone with shallow-water limestone clasts. fossils: ostracods (shallow-water forms, e.g., amphissitessp., typical moderate high energy shallow-water fauna of carbonate platform, cladocopida (p e r m o p o l y c o p e sp., p o l y c o p e sp.) and some pelagic ostracods (myodocopida, p e r m o c y p r i d i n a ? n. sp.)). e n v i r o n m e n t : slope debris flow. age: permian. geol. croat. 49/2 1161 . 162 1 zagreb 1996 1 st international symposium of petroleum geology economic aspects of petroleum exploration an approach to rational exploration zagreb, april 18-19, 1996 foreword the first international symposium of petroleum geology titled "economic aspects of petroleum explo­ ration an approach to rational exploration" took place in zagrcb on the is-19th of april 1996. the aim of the symposium was 10 enable the exchange of expe­ rience in the declaration and valuation of hydrocarbon reserves. it was organised by the croatian academy or sciences and arts (sc ientific council for petroleum, section of geology, geophysics and geochemistry) in co-operation with the facuily of mining, geology and petroleum engineering and the ina industrija nafte d.d., zagreb, as well as the european association of geoscientists and engineers from zeist. the sympo­ sium was held under the auspices of the ministry of science and technology and the ministry of economic a1tairs of the republic of croatia. on the basis or reg­ istrations received and the list com piled during the sympos ium , there were 120 participants, of which 30 were rrom abroad and 90 from croatia. a comprehen­ sive list is contained on page 349 . a total of 69 authors aetivcly part icipated by presenting 37 papers (both lec­ tures and posters). the aim is to follow the advance of exploration pro­ cedures across the world in croatia. both in the recent past and historically the economic aspects of explo­ ration have not been given adequate allention, and that's why the principal objective of the symposium was to give a review of the possible solutions for a sys­ tem 10 intensify exploration for the purpose of increas­ ing the recoverable oil and gas reserves. the following themes were suggested: a) prospectivity or exploration areas, b) an organisational approach to work on petrole­ um-geological projects, c) techno-economical evalua­ tion of petroleum-geological projects, d) petroleum related legislation (in the world and in croatia), and e) transition in petroleum economy (transition of petrole­ lllll economy). not one of the papers received was rejected on this occasion. the ina -naftap lin company print shop copied all the papers in the received form, and bound them in the booklet of "work ing materials" that was distributed among participants. the contents of the papers didn't allow a finn classification to be made according to the themes suggested and the refore the scientific committee made a selection in accordance to whether the papers are closely connected to exploration economics or mostly concerning geologica l matters. the succession of oral presentations was also defined in this sense. all the papers were subjected to a very strict review procedure before final publishing and it was planned to have them printed 2-3 months after the symposiu m. this was delayed due to some financial concerns. how­ ever, the understanding and support of the "geologia croalica" editorial office has enabled publication in this scientific journal, naturally according to the scicntific criteria accepted therein. each article has undergone a standard review procedure: checked by al leasllwo ref­ erees, as a rule one from croatia and one from abroad. the papers by the proceeding's editors reduced to appear as abstracts were subjected to only one, domestic review. based on the review's results a categorisation or the works was made: scientific paper, review paper, sci­ entific note, professional paper and abstract/note. because of the limited funds availablc the maximum number of the pages of original text was specified in the symposium circular. although many authors didn't strictly honour this suggestion, the limitation neverthe­ less conditioned the majority of the articles to be put by the reviewers in one of the categories or scientific papers. it should also be mentioned that the first fcw papers in the proceedings are introductory lectures mainly con­ cerned with the economic and legislative issues. as a 162 part of symposium events in the days preceding the official opening, two workshops were organised, main­ ly for the employees of ina-nartaplin . one given by mr roger m. nellisl or great britain titled "economic and riseal packages for attracting foreign oil explo­ ration capital" lasted for 1.5 days and another given by mr. michael hili of the netherlands under the titl e "exploration economics", partly financed by eage­ pace poundation, was a half-day seminar. both work­ shops were well attended and sllccessful. the programme of the symposium the official opening of the symposium was held on thursday, j81h of april 1996, beginning al 9 a.l11. after the croatian national anthem, the president of the pro­ gram committee, prof. dr. zvonimir hernitz declared the symposium to be open and read the short introduc­ tory speech . he then welcomed all the present represen­ tatives of thc patron organisations: prof. dr. nikola ru zinski, vice-minister of the ministry of science and technology, zcljko matisa, assistant of the minister of economy and dr. gerd zuneke, president of the pace foundation (programme for association and co-opera­ tion in earth sci ences) of european association of geoscientists and engineers from zeisl. in addition he welcomed the representatives of the organisers: aead. vladimir maje r, secretary of the natural science sec­ tion of the croatian academy of sciences and arts (h;\z u), prof. dr. krcsi mir jelic representi ng both the university of zagreb and the faculty of mining, geolo­ gy and petrolcum engincering, and marijan pejcic, executive manager of ina-nanaplin company. prof. dr. zvonilll ir j-lernitz proposed the opening session to be presided over by: velimir steinbauer, ina -naftaplin, zagreb, dr. gerd zuncke (germany) , dr. pero miae (sloven ia), aead. branka sakal' , hazu, zagreb, and prof. dr. josipa velie, faculty of mining, geology and petro leum engineering, zagreb. the meetin g was addressed by all the represent a­ tives or the patron organisations and organisers as well as dr. mato gazarek of the board of commerce from zagrcb, and then followed by the introductory lecture by roger m. nellist. throughout the symposium si mul­ taneous croatian and english translation was assured . the working part of the symposiu m commenced after a short pause. the morning session on thursday, geologia cro;qica 49/2 18th april, was presided over by roger m. nellist (gb) and prof. dr. igor dekanic (hr), and the afternoon ses­ sion by dr. gerd zuncke (d) and prof. dr. josip seccn (hr). on friday, 19th april, the morning session was presided over by prof. dr. alain mascle (f) and dr. bruno aljinovic (hr), and the afternoon sess ion by prof. dr. zaki bassiolll1i (usa) and prof. dr. krdimir jelic (hr). on friday, the second day of the symposium , after the afternoon break, the committee for conclusions (prof. dr. josip secen, prof. dr. josipa velie, dr. gerd zuncke, zeljko matisa, prof. dr. zvonim ir l-]ernitz) composed an adequate text , later accepted by the sym­ posium's participants without remarks, that refers pri­ marily to the croatian petroleum economy. prof. dr. zvonim ir hernitz then thanked all those who attended or took an active part in the work of symposium for their participation, especially the patron organisations, joint organisers and the sponsors. it should be emphasised that th e first s teps in the organisation of the symposium were made at an extremely unfavourable time, during late 1993 and ear­ ly [994 when parts of croatia were sti ll occupied. the official bulletin of the eage "first break" staned printing the information on the sympos ium in 1995. valuable and interesting contributions from in ternation­ al guests have to be acknowledged here. we wou ld also like to give special thanks to the main sponsors the ina-naftaplin company from zagreb and the european association of geoscientists and engince rs from zeis t, that grant ed financial support by the means of the pace foundation. eage-pace foundation was rep­ rescnted by indefa tigabl e dr. gent zuncke who fol­ lowed all the events with a vivid interest and was indeed in every moment rcady 1'01' co-operation. with­ out the funds provided by these two organisations the symposium would have been impossible to stage. the economics of petroleum geological exploration surely represents a vcry narrow speciality. having tak­ en in account the number of participants, thc lectures that were given, unfavourable circumstances (the st ill not entirely peaceful condition in the eastern part of croat ia) and the fael that this was the 1st international symposium, we are disposed towards believing that the symposium was succcssfui. we arc hoping to be able to follow these steps, and that we will meet again in even greater number in three years time. zagreb, december [996 zvonimir hernitz president of the program committee i geol. croat. 49/2 163 164 i i zagreb 1996 i. medunarodni naftnogeologijski znanstveni skup ekonomski aspekti istrazivanja nafte i plina pristup racionalnom istrazivanju zagreb, 18-19. travanj 1996. uvodna rijec prvi illcdunarodni naftnogcologijski znanstvcni skup pod naslovom "ekonomski aspekti ist razivanj a nanc i plina pristup racionalnom istrazivanju" adrian jc u zagrcbu 18-19. travnja 1996. ostvarcn jc s ciljcm izmjcnc iskustava ii iskazivanju i vrcdnovanju zaliha ugljikovoclika. organizatori su bili hrvatska akadcmija znanosti i li111jctnosli (znanstveni savjet za naftu, sekci­ ja za gcologiju, gcofiziku i geokemiju ) u suraclnji s rudarsko-gco[osko-nartnim fakultetolll i ina -nafta­ plinol11 iz zagrcba. pokrovileiji su bili ministarstvo znanosti i ichnologijc, minislars\vq gospodarslva i european association or geoscientists and engineers. tc111cljem prispjclih prijava i izradcnoga popisa tijckom trajanja skupa nazocno je bi lo 120 slldionika od toga 30 iz inozcmstva i 90 iz hrvatskc. cjcloviti popis nalazi sc na sir. 349 . aklivno je u radu skupa sudjelovalo 69 autora s 37 referata (usmcnih izlaganja i postcra). optimalni i raciona lni pristup istrazivanju mincral­ nih sirovi na predslavlja vrhllnsk i znanstvcni domet ii domcni ckonomske gcologije. na prvoj razini nalazc se istrazivanja koja omogucujll otkrivanje naftnih i plin­ skih lczista, zatim sjijedc istrazivanja koja se provodc raeli rcalnog obracunavanja zaliha ligljikovodika, dok lrecli fazli c ine is trazivanja tijekom samc proizvodnjc. sva su ta istrazivanja po svojoj narav i inlcrd iscip li­ nama. u razlicitim omjcrima ukljllcllju raclove iz bro ­ jnih znanstvenih podrucja, prvenstveno geologij e, geofizike i naftnoga rudarstva. napredak istrazivackih postupaka u svije tu pokll ­ sava se slijediti i ii i-lrvatskoj. oeito je cia je prezenta­ cija ll lom smislu poslignlltih rezultata oel velikog znacenja za nasl! zemljll. gospodarskim aspektima istrazivanja ii nedavnoj i daljoj proslosti nije bila posvcccna dovoljna pozornost i zato je glavni saclrz.aj skupa bio dati pregled mogllcih rjesenja prema kojem sustavu intenzivirati istrazivanja s ciljcm povccanja pri­ dobivih zaliha naftc i pjina. predlozene sll sljeclece tcmc: a) pcrspektivnosl istrazni h pros tora i racionalni prislup naftnogcoloskim islrazivanjima, b) organizacij­ ski pri stup izradbi naftnogcoloskih projckata, c) tchnicko-ekonomska ocjena naftnogeoloskih projekata, d) nartno zakonodavstvo (u svijclu i kod nas), c) priva­ tizacija u naftnom gospodarstvu (lranzicija naftnoga gospodarstva). od prijavucnih radova nij c u ovoj priliei odbijen niti jedan. zahvaljujuci naftaplinskoj ti skari svi su umno­ :len i u obliku kako su primljeni od autora, uvezani u knjigu i poclijeljeni suelionicima. raclovi svojim saclrza­ jcm nisll dopllstali ostra razgranieenja prcma predloze­ nim temama pa je znanstvcni oelbor nacinio sclckciju na radove vezane strogo na ekonomiku istraz.ivanja i na one koji su ii vecoj mjeri obraelivali geoloska pitanja. u tome je sm isl u odredcn i slijcel izlaganja na skupu . meclutim, svi su raclovi prije konhenoga objavljiva­ nja prosli vrlo strogi rcccnzijski posilipak. bilo jc pred­ videno da blldu tiskani 2-3 mjcscca nakon oelrzanog skupa, ali to sc nije dalo ostvariti raeli nckih i'inancijskih pitanja. zahvaljujuci razumijcvanjll i podrsci urednistva casopisa "geolog ia croatica" omoguccno je tiskanje ii tom znanslvcnom easopisu. stoga je svak i rael prasao ustalj cni reccnzijski postllpak: preglcdan je oel najmanje dva recenzen ta oel kojih .ic barem jedan iz inozcrnslva. raelovi lltvrdcni od urcdnika zbornika i casopisa "geologia croatica" kao sazcci prosli sl! sarno jcdnu, clomacu recenziju. temcljem rezullata reccnzija odrc­ dena je kategorija svakoga racla: znans tveni rad, pre­ g led ni rad, prc(hodna znanstvena obavijest, strllcni rad iii sazctak. racli ograniccnih financijskih s redstava najvcci broj slranica izvornoga teks ta propisan je ll raspisll skupa. ,6-, taka sc il1llogi toga nish s trik lno pridrzavali , ipak je ograniccnjc livj c lovalo cia su recenzenti najvcci broj rcfcrata odrcclili unu(ar katcgorija znanstvenoga rada. treba jos napolllclluti cia su sc u samoillc zborniku na prvim mjcs tim cl nas ia pozvall3 predavanja vczana pogjav ilo za pitanja gospodarstva i zakonodavslva. u sklopu skupa , ali pr ijc si uzbe nog dije la, uglavnom za cljc lal nike naftaplina g.g. roger m. nelli s! iz ve l ike britanijc i mi c hae l hilt iz nizozcmskc odriali su izuzclno llspjclc workshopovc g. ne lli sl 0 suvrc­ mcnim porcznim s ll slavima sa ciljcjl1 pr ivlacenja inozcmnih ulaganja u naftna istrazivanja (l1 irajanju oel 1,5 dana), a g. iliit 0 ekonomici nannih islraz ivanja (u trajanju ad pola dana). sueljclovanjc g . j-l ilta fina ncijski je polllogla eage-pace rondacija. o ti.jeku skupa svcc<lnos t otvaranja skupa bila jc u cctvrtak 18. travnja 1996. s pocc lkolll u 9 sati. nakon hrvatskc hilllne predsjcelnik progralllskog odbo ra prof. e1r. zvo­ nilllir he rnit z prog las io jc skup otvorcnilll. procitao jc kratko uvodno iz laganj e . nakon toga pozdravio jc pri sutnc prcd s tavnike pokrovitclja: prof. dl nikolu ruzinskog, z31lljcn ika ministra znanosti i tchnologij e, g . zc ljka mati su, pomocnika mini stra gospodarstva, i elr. gerda z unckea, predsjednika pace foundation (european assoc iat ion of geoscicntists and engineers). zalim je pozelravio prcdstavnike organizatora: a kade­ m ika vladimira majcra, tajnika prirodoslovnog razrcda l-irvat skc akadcmije z nanosti i umjctnos ti , p rof. ell'. krcs imira jc li ca koji j c preds tavljao svcuc ili stc ii zagrcbll i rudarsko-gcolosko -nartn i fakuitet, te g. marijan3 pejcica, izv rsnoga elirektora jna-nalhlp lina. prcd lozio je racl no prcdsjcdn is tvo: mr sc. veli mir stc inbauc r, inj\ -naftapli n, zagrcb, dr. ge rd z ullckc (njemacka) , el r. pc romioc (s lovcnija) , akademik branko sokai', hazu , zagreb, prof. dr. l osipa velie , rudarsko-gcolosko-naftni faku ltct, zagreb. skup su pozdrav ili sv i precistavni ci pokrovitelja i o rga nizatora ie e1r. malo gazarek iz gospodarske geologia croatic:l 49n koll1ore, a tada je g. roger m. nellist iz lozio svoje uvoclno prcdavanje. za eijel i tij ek skupa os ig uran je sillluilani hrvatsko-engleski prijcvod. nakon kratke s tanke zapoceo j e raelni e1io skupa. vodile lji sll bili u cetv rtak 18. travnja p rije poclne roger m. nellist (g8) i pro f. <if. igor dekanie (fir), pos lij e podnc df. gerel zuneke (d) i prof. elr. los ip seeen (j-ir); u pe tak 19. travnja prije podnc prof. dr. alain maseje (f) i dr. bruno a lj inovie (fir ), poslij e podnc prof. dr. zaki bass iouni (usa) i prof. e1r. kres i­ mir l e lic (hr). u pe tak, drugoga dan a za vrijcllle pos lij e pocl nev­ noga odmora odbor za zakij ueke (pro f. e1r. jos ip seeen, prof. <ir. jos ipa velie, elr. gerd zuncke, g. zcljko malisa, prof. e1r. zvonilll ir (-iernit z) izradio je odgovara­ juci teks t koji je oel sudionika skupa prihvacen bez prillljcclaba, a odnosi sc prcvcnstvcno na hrvat sko naft­ no gospodarstvo. nakon loga prof. ell'. zvonilllir he r­ nitz za hvalio je svilll pri s litnilll3 na sudjelovanju , a posebno pokrovitelj ima, o rganiz3 torima i sp0 i1z0rillla . na kraju valja istaknuli da se s prvilll korac ima oko organizacije skupa zapoce lo 1i izuzelno nepovotjno vr i­ jemc. jos krajcm 1993. i pocctko ll1 1994. godine dok jc did hrvat skc bio okupiran. sluzbeno glasilo eage " firs l break" pocelo j e s obavjestavanj clll 0 skupu 1995. god ine, pa ovdjc zais ta treba istakl1uti inozc ll1ne gosle koji su se odazv a li i izn ije li brojna vrijcdna i zanimlj iva izlaganja. spolllenimo jos tna -n a ft ap lin i eage kao g lavne sponzore bez c ije fin aneijske poll1oc i ne b i b ilo moguce odrzavanjc skupa ie neul11ornoga clr. gerda zunekea koji jc sa z iv im zanill1anjelll pral io sve dogadaje i ti svakomc irenutku bio sprclllan na surad­ llju. ekonomija llaftnogeo logijskih istrazivanja svakako predstavlja vrlo uskll spccijalnos t, ali s obzirol11 na broj slldionika, odrzana prcdavanja , okol nost i uos nc sasvim mimo s ianje na is!oku i-i rva ts kc) i s obz irolll cia j e to bio i. i1l cdunaroclni z nans lveni sklip s kloni sl110 vjerovati cia je uspio. naclajmo se cia ccl110 tim koraei ­ ma naslavi ti id a ccmo se u jos vcccill broju pon ovno vidjeti za tri god inc. zagre b, prosinac 1996. zvonim ir hernitz prcclsjeclnik programskog oclbora geol. c roat . 50/2 187199 i rig. i tab. 3 pi s. zagreb 1997 upper palaeozoic fossils from clastic sedimentary rocks in the gorski kotar region lasenka sremac ' and dunja al./inovic' key words: uppe r palaeozoic, foss ils, gorski kotar, croat ia. abstract clastic sedimentary rocks in the vicinity o f mrlle yodice in the gorski kot"r region contain numerous upper palaeozoic fossi ls, pre­ se rved as skele tal det rit us in calclithit cs. o r wi thi n lithocla~is in coarse-grained sedime nt s. seven ty-two taxa have been de termined (most of them for (h e first lime) in thi s region. the mosi abundant groups arc foraminife rs and calcareous algae. ca lcisponges, cc hino­ denus and bryozoans occur frequently. while remnants o f moll uscs, brachi opods and os tracods nrc scarce. the determined taxa range from ihe lower carboniferous (visean), through the upper carboni­ ferous (moscovian, kasimovian, gzhclian), up to the lowcr pcrmi an (asselian) in agc. somc of thc clastic sed imcn ts sho w traces o f the multi pic rcdeposit ion. 1. introduction i\t several localities in the vicinit y or mrzla vodica in the gorski kotar region (kosmacev brijeg hill and creeks: kriz potak, mrzli ca potak and l ezerine potok) clastic sediments have been sam plcd ror sedimentologi­ cal and palaeontological analysis (fig. i). the thickness of the clasti c com pl ex has bcen est im ated at approxi­ mately 150 m. at the exposed outcrops, heterogenous sed im cnt s occur: [1'0111 black shalcs and various sand­ stones (inc luding the peculiar calclithites) to ortho­ quartzit e and pctromicl conglomerat es and calcareous breccias. these sed iments alternate laterally and vert i­ call y, and some of the vari eties repeatedly appear in the verti ca l sec tion (alj inov ic et ai. , 1997). unfortu­ nat ely , in these wild forests, permi an ou tcrops are noi well exposed, and the complete sllccession cannot be observed. i dcp'li' llllcnt of geology anel palaeon lology, faculty of science , univcrs ity o f zagreb, uli ca kralja zvoniminl 8. i-ir -ioooo zagreb, croatia. ~ facully o f mini ng, geology and petroleum engineering, un iversi ty of zagre b, pierottijc\'a 6, iir ioooo zagreb, croatia. klju cne rijeci: gornji paleozoik, fos ili , gorsk i kolar, hrvatska. saietak kla!i tic ni sed iment] okol icc mcd ill vodi ca ii gors kome kotaru sad ric broj ne gornjopateo1.ojske fos il e, koji prcdslavl jaju skeletni de tri tus u ka lklil ili ma, ii i su pak unu tar litokillst a u kru pnoz rnati m sedimcn tim a. odredena sll seda mdesc td va tak so na, medu kojima je vecin:t po prvi puta naden<l u ovom podrucju. najccsci su nalazi foramini fcra i al gi, zalim kalcispongija, bodljikasa i briozoa, dok se neslo rjedc nadu mekusci , ramenonosc i i ostrakodi. mcdu nadenim sli vrstama i provodni fos il i donjega karbona (v izc), gornjega karbona (moskov ij, kasimov ij . gzelij) i donjega pe nna (asel ij). ncki fosili pokhzuju imgove vises lfukog prclalozivanja. 2. previous studies of palaeozoic fossils in the gorski kot ar uppcr palaeozoic rossils, predominant ly rusul inids and ammonoids, from gors ki kotar were studied for the first time by the austri an geolog ists sc hubert (1907) and vogl (191 3). croat ian geologis ts under thc lcadership or m. salopek prepared (he detailed geologica l maps o r ihis area (sa lopek, 1949, 1960). carboniferous " fu suli ­ nid" (triticites) sandstones and heterogeneous permian sed im ent s, ranging from the rattend orf 10 the sos io­ stage, have been distinguished in the vicinit y of mrzla vod ica (fig. i). salopek considered (he upper permian bellerophon beds to be absent in thi s regio n. fusul i­ nids, brachiopods and gonialite ammonoids were co l­ lected du ri ng these invest igations. unfortunately, some parts of (he area have been nooded during the constructhis paper was presented at the scientific meeting dedicated to the 80th anniversary of the life 01' professor milan herak , held on march 5th, 1997 in zagreb '88 geologia croatica 50(2 n 0 .. ~ 0 m en § co ~ g 0 0 r-~ <0 ~ iii u) ~ .,~ '" ~ , ~ n § 0 .~ § ~ d z< :;:; f-i g. i geo logical map of (he area surrounding mrzla vodica (aner salopek, 1960, partly modi fied). legend: [) q alluvial deposits: 2) j] limestone; 3) t3 do]omilc; 4) t i clastic sediments and dolomites: 5) p( j' barite, pyrite alld limonite deposits; 6) p sand stones; 7) p­ quartz-conglomerates; 8) p porous conglomerates; 9) p mass ive dark-coloured limeslones; 10) p black shales and sands tones in al(erna­ tion: ii ) p black shales; 12) p dark-coloured coarse-grained sandstones; 13) c triticite sandstones. srcl1lac & aljinovic: upper pal:teozoic fos.~ils from clastic sediment:l ry rocks ... lion o f the a rtific ial lake in lokve, includin g several fossili ferous outcrops with palaeozoic ammonoids and iytloniids. koc ii ansky -devide (i955), in he r pape r on carbon ife rous fusulinids from the velebit mi. , men­ tioned several new fusulinid species from gorski kotar, and determi ned the carboni ferous age o f the sedimenta­ ry rocks in the vicin ity of mrzla vod ica for the firs t time. koc ii ans ky-devide & herak ( 1960) descri­ bed the pe rmian species of alifhracoporella and i-licorocodillm from the same area. ko c hanskydevide (1 973) wrote abou t the trogkofcl beds in croatia. she interpreted the coa rse­ gra incd c lastic scdiments from mrzla vodiea as be ing the consequence of redeposition and unstable environ­ mental condi tions linked with the tectonic activity. the trogkofcl agc of the sediments from c iganski jarak local ity (pig. i ) has been proved with index species of pseudo/usu/if/a and ro/jiistosclnvagerina. the author observed the two new fu sulillid species from kri z pot ok creek, wh ich will late r be described by milanov ic ( 1982). milanovic ( 1982) described in detail the deter­ mined microfauna from kriz polok. the most abundant ge ne ra a t thi s locality arc triticifes and flislllinel!a , with scarce findings of schubertella, qllasiendothyra, permodisclis, and pseudostafella. among the ten taxa, two new spec ies, triticiles kochallskae and paratrit ­ ie·iles crooticus, were desc ribed. considering the pre­ domination of ke riothecal tests, milanov ic sugges ted the posl-kasi mov ian age fo r these sediments. pa li nkas & sremac (1989) described the bari­ te-bearing stromatolites from the vicin ity o f mrzla vod­ ica, taking inlo consideration the previous d ilemmas on the age or the barite bearing laye r. they c laimcd that the described sediments lie concordantly 011 the palaeo­ zoic clastic sedimcnts, and connect the formation of the stromhtolites with tidal flats, during the upper permian or lower triassic. although the index fossils of the uppermost permi­ an have not ye t been found in this area, numerou s aut­ hors cons ide r the sedimentation in gorski kotar to be continuous d uring the en tire pemlian and lower trias­ sic pe riods (sec herak & tomic, 1995). 3. palaeontological data micropalaeontological research of a ll the invest iga­ ted sedimentary rocks from the vic inity of mrzla vodi ­ ca resulted in numerous finding s of upper palaeozoic fossils. all together seventy-two taxa have becn de ter­ mined, wi th predomi nation of foraminife rs (thirty-two tax a) and calcareous al gac (twenty taxa , inc luding fif­ teen da syc ladaceans) . macrofossil remnants have al so bee n co ll ccted , predominantly calcispon ges, ammo­ noids, bryozoans and echinoderms, toge ther with scarce molluscs, brachiopods and ostracod s (table 1). over 189 50% of the de term ined taxa have been reported for the first time in this region. ext remely fossiliferou s limestone rragments come from conglomerates at the kosm<lcev brijeg and kriz potok localities. these pebbles contain approxi mately rourty diffe rent fossil taxa. fossil s from calclithites appear to be scarce and poorly preserved. determination of fossils was based upon the follow­ ing papers: conil & lys (1964), duc tien ( 1979), endo ( 1969), flogel (1980) , homann (1972), granier & deloffr e ( l 995) , kochansky­ devide ( 1959, 1970), konishi & wray (1961 ), roux (l979) and v achard (1980). almost half of the de termined species ha ve rather large strat igraphic ranges, but approx im ately twcnty taxa are strongl y indica ti ve of carbonife rous or pe rmi­ an ages. among the carboni fe rou s taxa, nine spec ies o f visean small foraminife rs (genera arc/wcdisclis, pa/ae­ ospirop/ecjammina , endothyra) occur (pi. i , figs. 4, 5, 7 and 12), toget her wit h several moscov ian or kasi­ mov ian spec ies. moscovian algae (genus gyroporcl/a) are shown on pi. iii , fi gs. 1-3, and kasim ov ian schu­ bci1clids and triticites appear on pi. ii , figs. 1-4. fij'tccn determined taxa (tetrataxis, e./lugelia, co­ diaceae, epimastopora, arractyliopsis, etc.) range from the gzheliall to the lowermost pe rmian, or indicate thc rattcndorr~stage of the lower pe rmian (see pi. 1, figs. 8, 9: pi. 1il, figs. 4-6). among the taxa that survived throughout the pc rmi­ an period authors have collected tuberirina (pi. i, figs. 2,3), lasiodisclis (pi. i, fig . 2), globivalvlililla (pi. i, fig. 11), pseudo!uslliina, c/aracrlfs{(i and tuhiphyles (pi. ii , fig. 7). two lagenid taxa, frolldilla and cryp­ foseprida have been previous ly reported o nl y from the upper permian sediments. 4. discussion it is a known fact that the age oj" clastic sedimentary rocks can rare ly be prec isel y de te rmined . either au tochtonous foss ils from the matrix are found, or the superposition rule is applied. bioc lasts from the vicinity of mrz la vodica are al most always damaged, and are presumably redeposi ted. the amount of algac is conside rably smaller in fine­ gra ined sediment s than in limesto ne pebblcs, varying from approximate ly 10% in ca lc lit h itcs up to 30 % in pebbles, because a lga l s ke le tons a rc less pe rs istent to destructi on than foraminife ral tests. t he age of thc de termi ned fossi ls varics fro m the lower carboniferous (visean), through the upper car­ bonifero us (moscovian , kasimovian, gzhelian ). to the lower pennian (asselian). fossi ls yo unger than lowcr permian have not been co ll ec ted during ou r inves tiga­ tio ns, but thcy have been report ed by the previolls authors. two specim ens or primiti ve lage nids do not provide sufficient proof for an upper pe rmian agc. '''" protozoa ordo: foraminiferida eichwald, 1830. subordo: textularjjna delage & herouard, 1896. l ' tolypammlna glomosplroldes bogus & jufeaev subordo: fusulinina wedekind, 1937. 2 eotuberitins reitlingerae mikluho maklaj 3 tuberitina collosa reitlinger 4 tuberltina sp. 5 archaediscus redilus conil& lys 6 permediscus sp. 7 eolas/cd/scus donbasslcus reitllnger 8 las/cd/scus minor reichel 9 climacammina e/egans (moeller) 10 palaeotextularla dlversa tschernyschev 11 deckerefla sp. 12 pafaeotextufsr/ldae gen. et. sp. indet. 13 globivalvu/ina ex. gr. bulloides brady 14 globlvalvullna sp. 15 dagmarlta chanakchlensls reitlinger 16 pafaeospiroplectammina sp. 17 endospiroplectammina venusta (vdovenko) 18 glomosplranella ? sp. 19 pseudolituotubella tenuissima vdovenko 20 plonoendothyra splrlllfniformfs bralnikova & potievskaja 21 planoendothyra sp. 22 endothyra prlsca rauzer -cernousova 23 bradyina sp. 24 tetrataxls ct. plana morozova 25 tetrataxls conlca ehrenberg 26 tetrataxis sp. div. 27 poly taxis maxima schellwein 28 schubertef/a australis thompson & miller 29 schubertello mjachkovensis rauzer-cernousova 30 schubertef/a klngj dunbar & skinner 31 schubertella sp. 32 fusullnella ct. bockl moeller 33 pseudofusulina ? sp. 34 tr/tlcjtes kochanskae milanovic 35 paratriticites croaticus milanovic subordo: miuouna delage & herouard, 1896. 136 apterinelfa sp. 137 calclvertella ? sp. subordo: lag en ina delage & herouard, 1896. 38 cryptoseptlda sp. 39 frondina permica sellier de civrieux & dessauvagie kos. b. = kosmacev brijeg iz valutica (from the pebbles) kos. b*. = kosmacev brijeg iz kalkutita (from calclitites) mrz. p. = mrzuca potok jez. p. = jezerine potok .... u> 0 a: .. .... u> d-c d1 p cz-p cz -p c, c c p c c, c cop cop cop p, d c, c, c, c, c, c, c, c i " pi c, c p cpi p, p c, p, c p, c, p c, c, c: p c:p p, p, uco!ogi:l croat ica son sremac & alj inovic ~ .. ~ 0 ~ ~ d 0 ~ • .~ ... n u o :::!:~~ " :!,;! 0 ' • .!. c: co ~ti.li!: kos. kos. mrz . jez. i;!!:!! > ~ g!! e ~ ~~:=. 00 . krj:z 0_ ~ ~ e'" 0 -"", 0 0 ~g;:) b. bo. p. p. ~~ u> _ 1: " ::." .::'" a: 0 • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • --• • • • • • • • • • • • • • • • • • • • • • i~ • • • • • • • • • • • • • • • • • • • • • • • • • • • ? ? • • r---• • • table i list of the determined taxa from di fferentlocal il ies in the vic init y of mrz le yodice with slfmigraph ic ranges and comparative li sls. sremac & aljillovic: upper pnlneozoic fossils from clastic sedimentary rocks .. . 191 sremac & aljinovi6 ~ 00 ~ f0 ~ m jj 2w m ~3:' s p 0 n g i a e n 00§ 0:", ·0 ~~ 0 0 0 ::<~, .> >~ .' , ecij ,tf){3 ..11: .. " kos. kos. o~ e~ n,gs 15~ :! f-kriz mrz. jez. a;: g!! ~~ u) b. b'. p. p. om 2'-' e 1: =:::.:: =~ u) ~~ £ 0 ::< ::<" 40 claracrusta calamistrfata vachard p • • 41 asteractinella ? sp. p • • • 42 calcispongiae gen. et. sp. indet. pz-rec • • • • -43 gastropoda pz-rec • • • • • • 44 ostracoda pz-rec • • b r y 0 z 0 a • • 45 fenestella ..c-p • 46 tip a ~ ? • 47 tip b t pz-rec • • • • 4b brachiopoda pz-rec • • echinodermata 49 crinoidea pz-rec • • • • • • 50 i echinoidea pz-rec • • • • shizophyta 1511 girvanella permica pia r---i-c, • , -rhodophyta 52 eflugelia johnsoni (e. flugel) c 2 p, • • • chlorophyta codiaceae 53 anchicodium magnum (endo) c2 pi • 54 eugonophyflumjohnsoni konishi & wray c 2 p, • • 55 neoanchicodium catenoides en do p, • • • dasvcladales 56 donezella sp. c 2 p, • • 57 vermiporella ? sp. c-p • 5b anthracoporella spectabilis pia c-p • • • • 59 gyroporella likana kochansky devide c, • • 60 gyroporejfa constricta kochansky devide c, • • • 61 gyroporelfa microporosa en do p • 62 gyroporella sp. c 2 j, • • 63 pseudogyroporelja mizziaformis en do c~p • • • 64 epimastoporella alpina kochansky herak p, • • • 65 epimastopora kroatiaca homann c 2 p, • • • , 66 epimastoporelja sp. c 2 p • 67 paraepimastopora kanumai en do c 2 -p • 6b atractyliopsis carnica e. flugel p, • • ? 69 salopeklella sp. c1. s. ve lebitana milanovi.~~ (?_ ortonella morlkawai endo) p • • 70 goniolinopsis ? sp. p • problematica 71 tubiphytes obscurus maslov c2 p • • • • • • • 72 tublphytes carinthiacus e flugel p • 1l)2 the amount of algae varies not only with grain size, but also with the age of clasts. the first diverse mierofloral community can be extracted from the moscovian pebbles, and the most abundant algae have been observed within clasts of gzhelian to asselian age. according to the sedimentological features, the investigated sediments show the greatest sim ilarity to the clastic trogkofcl beds from ortnek in slovenia, described by ramoys & kochansky-deyide (1965). the authors claim that the development of the trogkofel stage in the vicinity of mrzla vodica and cr­ ni lug cou ld not be very different from that in the ort­ nek district. they also presume that the clastic sedimen­ tation in these localities has began in the lower permi­ an (ramoys & kochansky-deyide, 1965, p. 69). clast ic equivalents of the trogkofcl beds have also been reponed from boreholes in southern hungary, hrvatsko zagorje and medvcdnica mt. (berczi­ makk & kochansky-deyide, 1981). 5. conclusion clastic sedimentary rocks from the vicinity of mrzla vodica in the gorski kotar district have been studied at the localities kosmacev brijeg hill and the kriz potok, mrzlica potok and jczerine potok creeks. seventy-two fossil taxa have been determined from conglomerate pebbles and calclithites, among which more than half are newly described in this region . the most abu ndant fossils are foraminifers (thirty­ nine taxa) and calcareous algae (twenty-two taxa). these species arc in association with macrofossils (sponges, molluscs, ostracods, bryozoans, brachiopods and echinoderms). approximately half of the determined species are indicative of particular periods in the carboniferous (visean, moscovian, kasimovian, gzhelian) or the lower permian (asselian), while the other taxa show a wider stratigraphic range. marine trogkofel fossils have been reported by previous authors. therefore a continuous marine sedimentation from the lower car­ boni/·erous (visean) up to the trogkofel stage has been presumed for this area. foraminifera predominate in visean and kasimov­ ian clasts, and calcareous algae are most abundant in the moscovian pebbles, as well as in gzhelian to asselian clasts. therefore, a variation of sea level can be presumed, with extrcmely shallow water conditions during the moscovian and at the carboniferous/penni­ an border. it has been concluded that the uplift of the sedimen­ tary basin in the study area began after the lower per­ mian, cnab ling deposition of the molasse deposits. shallow-marine sedimentation was restored presumably in the lower triassic. sedimentologically, these sedilicologja lroallca :jufl mentary rocks show the greatest similarity with the clastic trogkofel beds of the neighbouring areas. the age of the investigated clastic scdiments could not be precisely determined. nevertheless, it can be concluded that they are younger than the lower per­ mian. 6. references aljinoyic, d., sremac, j. & koch, g. (1997): upper paleozoic sedimentary rocks from gorski kotar, croatia: new sedimentological and paleonto­ logical data.18th regional european meeting of sedimentology, sept. 2-4, 1997, abstracts, gaea heidelbergensis, 3, 42-43, heidelberg. bercz1-makk, a. & kochansky-deyide, y. (1981): marine lower and middle permian in the oil exploratory well ujialu-! (sw hungary).acta geol. acad. sci. i-lung., 24/1, 11 7128, budapest. conil, r. & l ys, m. ( 1964): materiaux pour l' etude micropalcontologique du dinantien de la belgique et de la france (avesno is).mem. ins\. geol. univ. louvain, 13, 1-292, louvain. duc t1en, n. (1979): e tude micropateontologique (foraminiferes) de materiaux du permien du cam­ bodge.unpublished phd thesis, univ. paris sud, centre d'orsay, paris, 166p. endo, r. (1969): fossil algae from ihe khao phlong phrab district in thai land.in: koba y ash!, t. & toryama, r. (eds.): geology and palaeontology of se asia. 7, 33-85, tokyo. flugel, e. (1980): die trogkofcl-stufe im unter­ perm der karnischen alpen.carinthia, ii/36, 1260. homann, w. (1972): unterund tief-mittelpcrmische kalkalgen aus den rattendorfer schichten, clem trogkofel-kalk lind dem tressdorfer kalk del' kar­ nischen alpen (osterreich).senckenbergiana lethaea, 53/3-4, 135-313. granier, b. & deloffre, r. (1995): inventaire critique des algues dasycladales fossiles, iii partie les algues dasycladales du permien et du trias.­ revue de paleobiologic, 14/1 (1994),49-84. herak, m. & tomic, y. (1995) : continental sub­ duction tectonics in the high karst dinarides of western croatia.geol. croatiea, 48/2, 161-166. kochansky-deyide, y. (1955): karbonske i per­ mskc fuzulinidne foraminifere velebita i like. l. opci dio i karbon.rad jugos!. akad., 305, 5-62, zagreb. kochansky-deyide, y. (1959): karbonske i per­ mske fuzulinidne foraminifere velcbita i like. do­ nji perm.palaeontol. jugosl., 3, 1-62, zagreb. srcln;)c & aljinovic: upper pal;leozoic fossils from cla~tic sedimenrm), rocks ... koc!-iansky -devide, v. (1970): die kalkalgen des karbons yom vclcbit-gebirge (moskovien und kassimovicn).palaeont. jllgosl. , 10,5-3 1, zagreb. kochansky-devide, v. ( 1973): trogkofelske na­ s lage 1i hrvatskoj. (die trogkofelablagerun gcn in kroatien).geol. vjesnik, 26 (1972), 41-51. kochansky-devide, v. & herak, m. (1960): on the carbonife rou s and pe rmi an oasycladaeeae of yugoslavia.geol. vjcsnik, 13,65-96. konishi , k. & wray , j.l. (1961): eugonophyiium, a new pennsylvanian and permian algal genus.j. pal. , 35/4, 659-666, menasha. milanovic, m. ( 1982): carboniferous microfossil associat ions [rom gorsk i kolar , i-irvatsko zagorje and banija.pal aeon i. jugosl., 28, 1-34, zagreb. pali nkas, l.a. & sremac, j. ( 1989): barite bear­ ing stromatolitcs al ihe permian-triass ic boundary in gorski kotar (c roatia , yugoslavia).mem. soc. geol. 11. ,40 (1987), 259-264, roma. ramovs , a. & kochansky-dev ide, v. (1965): razvoj mlaj sega pa lcozoika v okol ici orlneka fl a dolenjskem.razprave iv. razr. sazu, 8, 319-416, ljubljana. 193 roux, a. ( 1979): revi si on du genre epimastopora "pia , 1922" (dasycladaeeae).bull. centres reeh. exp lor.-prod. ei f-aqu itaine, pau, 3/2, 803 -8 10, paris. salopek, m. (1949): gornji pal eozo ik u okolini mrzle vodiee u gorskom kotaru. ljetopis jugosl. akad. , 55 , 175-184, zagreb. salopek, m. (1960): 0 gornjem paleozoikuu okolini mrzle vodicc i crnog luga.acta geol., 2, 121138, zagreb. schub ert, r. (1907): vorl iiufige mitteilung tiber foraminifercn und ka lkajgen <iu s clem dalmatini s­ chen karbon.verh. geol. reichsansl., h. 8, 211 2 14, wien. vachard , d. (1980): tethys et gondvana au paleo­ zoique superieur ics oonnes afghanes.doc um. trav. igal, 2, 396-397, paris. vogl, v. ( 1913): die palaeodyas von mrzla vodica in kroalien.mitleil. aus l ahrb. ungar. gcol. re ich­ sansl. , 2 i, 153-168, budapesl. manuscript received apri l 14, 1997. revised manuscript accepted november 10, 1997 . 194 geologia croatica 50/2 plate i foraminifers i toiypammina giomospiroides bogus & juferey; x 50. 2 tliberitina collosa reitlinger, lasiodisclis millor reichel; x 25. 3 eotllberitilla reitiillgerae mikluho-maklaj; x 50. 4 pialloelldothyra sp.; x 50. 5 archaedisclis reditus conil & lys; x 50. 6 palaeotextularia sp.; x 50 7 palaeospiroplectammina sp., bradying sp.; x so. 8 tetrataxis conica ehrenberg; x 25. 9 tetrataxis sp.; x 25. !o tetrataxis cf. piana morozov a encrusted with tubiphytes and bryozoans; x 50. ii clobiva/vliiijl([ ex gr. bullaides brady; x 40. 12 plalloendothyra spirillinijormis braznikoy a & potieyskaja, epimasloporella alpilla kochan­ sky & herak, fenestella sp.; x 40. age and locality: 2-3 4 5,7, 12 6 8 9, 10 11 12 carboniferous, kosmacev brijeg (from the pebble). permian, kosmacev brijeg (from the pebble). lower carboniferous (visean), kriz potak. lower carboniferous (visean), kosmacev brijeg (from the pebble). carboniferous or permian, kosmacev brijeg (from calclithites). carboniferous or permian, kriz patak. uppcr carboniferous (moscovian), kosmacev brijeg (from the pebbles). carboniferous or permian, kriz potak. lower carboniferous (yisean), kosmacev brijeg (from the pebbles). plate] sn:iil;i!,; & aljinovic ~----------------------------------------------------------195 6 7 8 9 10 12 plate ti fusulinids and microfoss il particles schuberlel/a killgi dunbar & skinner; x so. 2 scllliberrel/a auslra/is thompson & miller; x so. 3 hilieiles kochallskae milanovic; x 50. 4 paralrilieiles eroo/ieus milanovic; x 50. 5 epil1lasloporel/a a/pilla kochansky & herak, aplerillel/a sp.; x 50. 6 cryploseplida sp.; x 50. 7 tubiphyles c(frill/iliaeus e. flogel within the brachiopod shell; x 10. g ostracods in the central cavity of a calcisponge; x 25. age and locality: 1-2, 5 3 4 6 7,8 lower permian (asselian), kri i patak. upper carbon iferous (kasimovian) , jezerine patak. upper carboniferous (kasimovian), kosmacev brijeg (from calc lithites). ?upper permian , kosmacev brijeg, ([rom the pebble). pennian, kosmacev brijeg ([rom the pebbles). ucologla croallca )ufl. srernac & aljinovic plate ii 197 1 2 5 " . . " ~ 6 7 8 198 geologia croalica 50(2 plate iii calcareolls algae 1,2 gyroporella likalla kochansky-devide; x 25. 3 g. collstricta kochansky-devide; x 25. 4 epil1lasropora kroatiaca homann, atracty/iopsis camica e. flu gel; x 50. 5 epilllastoporelia a/pilla kochansky & herak; x 25. 6 neoallchicodium catcnoides endo encrusted with girvgllclla permica pia; x 50. 7 n. calelloides, alllllracoporella sp ec/abi/is pia, macrofossi l fragments encrusted with thick cyanobacte­ rial crusts; x 10. age and tocality: 1-3 upper carboniferous (moseovian), kriz pot ok. 4-5 lower permian (asselian), kosmacev brijeg (from the pebbles). 6-7 lower permian (asselian), kriz potak. srcm;ic & aljinovic 5 6 7 200 lieologla croatlea ::,u/l fintor.indd 75 � ab stra ct in many parts of the metapelitic (gneiss, mica schist) rock section of the baksa complex, signifi cant wall-rock alteration is observable along the ca-al silicate veins, which show a di → ep ± czo →sp → ab ± kfs → chl → adu → prh → py → cal mineral sequence (fintor et al., 2009). these alterations appear as narrow (few cm thick) bleached margins beside thin veins, and broad alteration bands along thick veins where detailed epidotization and chloritization of the adjacent rock are recognizable. based on petrographic and mineralogical examination of the altered wallrocks, metasomatic zones with characteristic mineral paragenesis can be distinguished: zone 1 (ab + ttn ± ep), zone 2 (ep + chl+ ttn + ab ± ser), zone 3 (chl + ep + ser + rt ± ttn), zone 4 (ser ± chl). bulk rock chemical analyses were made from the different metasomatic zones. the results show that fl uid circulated in the propylitic veins caused metasomatic alteration of the wall-rock, with transport of considerable amount of ca2+ toward the adjacent rocks. the hydrothermal leaching almost totally removed the k, fe, mg, and mn ions from the wall rock. the main alteration processes are the epidotization and chloritization of biotite, and albitization of micas (muscovite + biotite) content of metapelites. based on mobilization of different cations alteration was due to a near neutral fl uid (~ph 5–7). the pervasive hydrothermal leaching caused signifi cant secondary porosity (cavities) in the altered domains, which were partially fi lled by epidote. fluid inclusions of cavity fi lling epidote indicate a similar character (th: 180–360 °c; salinity: 0.2–1.6 mass% eq. nacl) to that can be found in ca-al silicate veins. the alteration most probably occurred in the 360–480 °c temperature range as products of 'near vein metasomatism' and the altered rock can be related to the propylite metasomatic family. keywords: baksa complex, metasomatic zones, epidotization, chloritization, element mobilization, hydrothermal leaching, propylitization near vein metasomatism along propylitic veins in the baksa gneiss complex, pannonian basin, hungary � krisztián fintor1, tivadar m. tóth1 and félix schubert1 1department of mineralogy, geochemistry and petrology, university of szeged, h-6701, szeged, p.o. box 651, hungary; (efkrisz@gmail.com; mtoth@geo.u-szeged.hu; schubert@geo.u-szeged.hu) doi: 104154/gc.2010.05 geologia croatica 63/1 75–91 11 figs. 3 tabs. zagreb 2010 geologia croaticageologia croatica 1. introduction the wall rock alteration activity of hydrothermal fl uids that circulate in fractures of crystalline rock bodies of the continental crust, has a signifi cant role in different geological processes. considerable secondary porosity may develop if metasomatic alteration is associated with leaching, and the locally increased porosity can play a pivotal role in the hydrological behaviour of otherwise low permeability crystalline rocks (mazurek et al., 2003; jakob et al., 2003). another important aspect is that hydrothermal metasomatism can be frequently associated with formation of mineral deposits. ore mineral deposition sometimes containing sulphide minerals (pyrite, chalcopyrite, pyrrhotite, and sphalerite) iron oxides (hematite, magnetite), or in other cases geologia croatica 63/1geologia croatica 76 stead covered by thin (50–100 m) tertiary and quaternary sediments in the area of the görcsöny ridge. the crystalline schists of the babócsa complex border the bc to the west (fig. 1). the villány deep fracture zone (kassai, 1972), which has a nw–se strike, separates the baksa metamorphic block from the mórágy granite complex, and permotriassic sediments to the east. the mecsekalja tectonic zone borders the complex in the north. it separates metamorphic rocks from non-metamorphic mesozoic sediments of the mecsek mountains (fig. 1). further to the south, formations of the complex can be traced over the slavonian regions, in the papuk and krndija mountains. petrology and metamorphic evolution of the bc has been investigated by many researchers (ravasz-baranyai, 1969; szederkényi, 1976, 1983; árkai, 1985; árkai et al., 1999; király, 1996; horváth et al., 2003). the complex consists of polymetamorphic rocks, mainly gneiss, marble bearing mica-schist, dolomite, marble, and amphibolite. five metamorphic events can be detected in the rocks of the bc. ravasz-baranyai (1969) detected a high pressure phase that was followed by a signifi cant decompression. the peak conditions of this p–t path were around 1300–1500 mpa and 600–650 °c down to approximately 800 mpa and 500 °c (horváth et al., 2003). peak conditions of the barrowian event (szederkényi, 1976) occurring after the previous high pressure phase, were around 750±50 mpa, and 660±20 °c according to árkai et al. (1999), but király (1996) suggests conditions of 500–700 mpa and 540–650 °c. after the barrowian event, the area underwent secondary albitization and isothermal decompression down to 440±20 mpa and 650±40 °c according to árkai et al. (1999) or < 200 mpa, 400–560 °c according to király (1996). the isothermal decompression was followed by contact metasomatism related to aplite intrusions. these aplite dykes with unknown origin, caused considerable alteration but only in the carbonate rocks of the complex. signifi cant alteration products include epidote, diopside, garnet and a wide spectrum of sulphide minerals. there are indications of two phases of hydrothermal ores in the rock body, an earlier phase with disseminated ores, can be distinguished form a younger formation of veins with massive sulphide infi llings. in the earlier phase, minor amounts of pyrite, and sphalerite grew sporadically in the veins. fintor et al. (2009) determined a ca-al silicate dominant mineral assemblage with a di → ep ± czo →sp → ab ± kfs → chl → adu → prh → py → cal mineral sequence (mineral abbreviations after siivola & schmid (2007), table i., except for adularia: adu). a detailed geochemical and fl uid inclusion investigation of the vein fi lling minerals indicates that mineral precipitation occurred during cooling of the hydrothermal system. the t-x character of the fl uid changed from high tem perature (467–370 °c) and low salinity (0.2–1.5 mass% eq. nacl) down to lower temperature (~150 °c) and lowto moderate salinity (3–6 mass% eq. nacl) appear in fl uid inclusions of diopside, epidote, and calcite phases (fintor et al., 2009). chlorite thermometry data (300 → 140 °c) also supports decreasing temperatures during the vein fi lling process. many of these studied veins are surrounded by 0.5–2 cm thick alteration halos. precious metal minerals, can occur during hydrothermal me tasomatism that mainly relates to magmatic intrusions (zha rikov et al., 2007; scherban, 1996; gryaznov, 1992; rusinov, 1989). study of wall rocks where alteration is caused by hydrothermal fl uid/rock interaction, may provide important information about the thermodynamic parameters (e. g.: ph, eh, t, p, x) of fl uids circulated in the rock body (parsons & lee, 2000; kullerud, 2000; gresens, 1967; meyer & hemley, 1967). the study area is the baksa complex which represents part of the metamorphic crystalline basement of the southwestern area of the pannonian basin. the baksa-2 exploratory drillhole penetrated deeply into the baksa complex. with almost 100% core recovery, this exposed almost 1200 m of crystalline rocks of the basement. it is the most complete drillcore available from the crystalline basement of the pannonian basin. a lot of evidence for postmetamorphic hydrothermal fl uid migration and alteration can be observed in the drillcores of the baksa-2 well. this alteration can be grouped into two main hydrothermal mineral parageneses. tarnai (1997; 1998) provided detailed studies of a thick (6–7 cm) sulphide ore vein, cross cutting the metamorphic block. ore paragenesis (pyr+po+sp+hem+ccp+gn+pn) and fl uid in clu si on studies of the vein fi lling minerals indicate a postmagmat ic hydrothermal origin (tarnai, 1998). the other assemblage suggests that the hydrothermal effect is the occurrence of ca-al silicate dominant fracture fi lling in several baksa gneiss samples (szederkényi, 1979). comprehensive examination of the latter vein-fi lling process was made by fintor et al. (2009) and they report the presence of sporadic pyrite crystals among the ca-al silicate minerals. detailed mineral chemical analyses of pyrite crystals from both the ca-al silicate and the thick sulphide veins (fintor et al., 2009) exhibit similar co/ni ratios (1–5), which is in the range of pyrites formed in postmagmatic hydrothermal systems (price, 1972). in this study, detailed petrographic, bulk rock chemical, and fl uid inclusion analysis of the altered wall rocks along the ca-al-silicate veins was undertaken. the aims are to detect the type and physicochemical conditions of metasomatism and element mobilization that occurred along the veins, and to determine the hydrological relationship between the alteration halos and the veins. 2. geological setting the baksa complex (bc) is located in the sw part of the tisza mega unit (fig. 1), a microplate that forms the basement of south hungary. the tisza mega unit was originally part of the european margin of neo-tethys and was separated from the european plate by opening of the penninic ocean (alpine tethys) (géczy, 1973; haas & péró, 2004). szederkényi (1996) divided the pre-alpine basement complexes of the tisza mega unit into three major parts: the paraautochton, békés-codru (bc) and drava terrains, and related the bc to the drava terrain. the metamorphic formations of the complex do not outcrop. they are infintor et al.: near vein metasomatism along propylitic veins in the baksa gneiss complex, pannonian basin, hungary geologia croatica 77 upper marble section (57–224 m) chloritic two-mica gneiss (224–822 m) lower marble section (822–867 m) garnetiferous two-mica gneiss (867–922 m) garnetiferous two-mica schist (922–1200 m) upper marble section marble and dolomite marble are the predominant rock types in this section with gneiss and mica-schist intercalations. aplite dykes frequently occur in the section and signifi cant alterations in carbonate rocks can be related to them. these alterations are accompanied by the formation of calc-silicate hornfels with epidote and diopside. ore showings caused by hydrothermal fl uids are also common. the most signifi cant ore vein (6–7 cm thick) is found at 186.4 m depth. the formation conditions and ore mineral paragenesis (pyrite, pyrrhotite, sphalerite, chalcopyrite, galena, pentlandite, hematite, covellite, marcasite) of the vein were investigated in detail by tarnai (1997; 1998); who assumed that these veins were formed in relation to the rhyolitic volcanism that occurred near the northern margin of the villány mountains (fazekas & vincze, 1991). a detailed investigation of mineralogy and ore genesis of the veins with massive sulphide ore infi llings was carried out by tarnai (1997, 1998). in a study of fl uid inclusions of the quartz which was cogenetic with the later ore minerals, he determined a trapping temperature (tt), of 240 to 300 °c and trapping pressure (pt), of 15–30 mpa (tarnai, 1998). the youngest alteration phase that can be investigated in the rocks is a retrograde greenschist facies event, which caused chloritization and secondary albitization (szederkényi, 1979). its temperature range is assumed to be 200–400 °c by árkai et al. (1985). the beginning of this event is related to the alpine orogeny (szederkényi, 1984). fintor et al. (2008) detected traces of high salinity fl uids (~20–25 mass% eq. nacl) in the post-metamorphic quartz-carbonate veins that penetrate the rock body. using microthermometry, they obtained conditions of approximately 80–180 °c and 20–100 mpa for the formation parameters of the quartz-carbonate veins. the baksa-2 exploratory well (bottom-hole: 1200 m) enables the most detailed investigation of the bc (fig. 2). it exposes the crystalline basement formation with a total thickness of over 1100 m and near 100% core recovery. the metamorphic mass was divided (szederkényi, 1979) into the following lithostratigraphic units: fi gu re 1: the geological map of the baksa complex and its environs is presented without tertiary and quaternary sediments. legend: 1. baksa complex (study area), 2. babócsa complex, 3. mórágy complex (car bo niferous), 4. carboniferous sediments, 5. permian formations, 6. triassic formations, 7. jurassic formations, 8. cretaceous formations, 9. mecsekalja tectonic zone,, 10. villány-szalatnak deep fracture zone. inset: location of the study area (bc) in the pannonian basin (alcapa and tisza mega unit are also represented on the map); inset legend: 1. flysch belt, 2. pieniny klippen belt, 3. inner carpathian mountain belt. geologia croatica 63/1geologia croatica 78 chloritic two-mica gneiss this section is composed of two-mica gneiss and schist with some amphibolite. signifi cant chloritization (after biotite) is observed in some parts of the rocks (szederkényi, 1979). aplite dykes are rare in this section and a cross-cutting biotite-andesite dyke is observed in a fault zone at approximately 460 m depth. lower marble section this section is comprised of amphibolites, although marble intercalations are the most important rock type of the section. the marble bands are almost pure dolomite. this section is very rich in aplite dykes, which caused alterations similar to those found in the upper marble section. garnetiferous two-mica gneiss this rock section is dominated by gneiss with some mica schist intercalations. large garnet grains (> 2 cm in diameter) are a common occurrence throughout the section. aplite dykes do not occur in this section. garnetiferous two-mica schist this section consists predominantly of mica schist, with lesser amounts of gneiss and some amphibolite. garnets with similar characteristics to those of the garnetiferous two-mica gneiss also occur in considerable amounts. one aplite dyke was discovered in the section, which suffered comprehensive epidotization and tourmalinization. 3. samples and methods samples used for analysis were collected throughout the profi le of the baksa-2 drillhole, as detailed locations on fig. 2 show. mineral abbreviations used in the whole study (table i) are after siivola & schmid (2007). x-ray element maps and bulk rock chemical analyses were made using a horiba jobin yvon xgt 5000 x-ray fl uorescence spectrometer. beam diameter was 100 μm and acceleration voltage was 30 kv in each case. bulk analyses were made from 5 mm x 5 mm areas of rock surfaces. analyzed areas were divided into 512 x 512 pixels with 0.01 mm2 size of each pixel. natural standards were used for standardization of each measured element. the surfer 8 surface mapping system was used for the representation of element maps obtained by xrf analyses. isocon analysis was made from bulk rock chemical data using the computer program geoiso (coelho, 2006). this program can calculate and plot (isocon diagram), the mass and volume changes that can occur in a wide variety of open system geological processes. the isocon diagram is based on the study of grant (1986, 2005) and is a simple solution to gresens (1967) equation for metasomatic alteration. gresens’ basic argument is that some components are likely to have been immobile during the alteration process, and if these can be identifi ed, they can be used to establish any change in volume which has taken place. gains or losses of other components can then be calculated, assuming that the volume change is a factor common to the behaviour of all components. gresens (1967) shows that the transformation of a generic rock a into another generic rock b can be expressed as follows: xn = [fv (gb / ga) c bn – c an] a fi gu re 2: lithological profi le of the baksa-2 borehole. (after szederkényi, 1979) legend: 1. biotite-andesite dyke 2. aplite dykes 3. amphibolite 4. marble and dolomite marble 5. two-mica gneiss 6. chloritic gneiss 7. chloritic schist 8. two-mica schist 9. sampling points. fintor et al.: near vein metasomatism along propylitic veins in the baksa gneiss complex, pannonian basin, hungary geologia croatica 79 where “x” is the mass change of component “n” relative to “a”, “n” the considered component, “g” the densities of each rock, “v” the volume of each rock, “fv” a volume factor, “a” the mass of the original sample (a) and “c” the concentration. even if effi cient, the gresens’ method is neither easy nor practical to use. grant (1986) proposed a more direct and easier process of using gresens’ equation in the following expression: c fi = (m0 / mf) (c 0i + dci) where “c fi” is the resulting concentration of component “i”, “mo” is the mass of the original, while “mf” is the mass of the transformed rock, “c 0i ” is the original concentration of component “i” while “δci” is the change of concentration of component “i”. for each component there is an equation of this form, in which (mo/mf) is constant. the “perfectly inert” elements must defi ne a line c fi = f(c 0i ), of slope mo/mf passing through the graph origin. the line connecting “points with the same concentration”, gary et al. (1974), is defi ned as an “isocon”. using the computer software geoiso, the whole rock mass change (mf-mo/mo) and volume change (vf-vo/vo) are also calculable. the program estimates the element mass changes during alteration using two different approaches. in one case the program compares each elements mass change to the original rock mass: (m fi– m 0i) m0 = (mf / m0) m fi – c 0i where m fi is the mass of component “i” in the transformed rock, and m 0i is the mass of component “i” in the original rock. alternativley, the program compares each elements mass change to its mass in the original sample: (m fi– m 0i) m 0i = (mf / m0) c fi / c 0i – 1 given the better approach, the latter equation was used in this study to estimate element mass changes. in our study we use the nomenclature and abbreviations by grant (1986). densities of the different metasomatic zones were calculated using the theriak (holland & powell, 1998; de capitani, 1994; de capitani & brown, 1987) thermodynamic program package. fluid inclusions were studied in 75–150 μm double-polished thick sections prepared from the vein fi lling minerals. microthermometric measurements were carried out by means of a linkam thmsg 600 heating-freezing stage, operating over a temperature range from –190 to 600 °c. synthetic fl uid inclusions were used to calibrate at –56.6, 0.0 and 374.0 °c. the accuracy of the data is ±0.2 °c under freezing and ±0.5 °c under heating conditions. an olympus lmplanfi 100x objective was used to analyze the inclusions. the cycling method (goldstein & reynolds, 1994) was used to determine the last ice melting temperatures, and each melting of ice occurred in the presence of a vapour phase. estimations of volume fractions of vapour bubbles (φvap=vvap/ vliq+vap) were obtained from area analysis of a two-dimensional projection of the fl uid inclusions. terms and symbols of diamond (2003) were used. the computer package fluids (bakker 2003) was used to calculate fl uid properties. the program aqso2e was used to calculate salinities in the nacl-h2o systems (naden, 1996) based on the equivalent mass % principle. the program bulk (bakker, 2003) allowed us to calculate the bulk fl uid properties molar volume (vm), and bulk composition of individual fl uid inclusions. this calculation was accomplished using a purely empirical thermodynamic model, the equation of state for electrolyte-bearing aqueous solutions of krumgalz et al. (1996) and the volume fractions of the liquid phase of the inclusions at room temperature. a jobin yvon labram confocal raman spectrometer, equipped with a frequency doubled nd-yag laser (100 mw, 532.2 nm), with a 100x/0.80 objective lens was used to identify fl uid phases in inclusions. the spectrometer was calibrated using a silicon chip. the spectral resolution of the instruments was 4 cm–1 and the spatial resolution was a few μm3. the acquisition time was 100 s with 20 s accumulation periods in each spectrum. 4. results 4.1. petrography and mineralogy in many parts of the metapelitic (gneiss, mica schist) section of the bc, signifi cant wall-rock alteration is observable along ca-al silicate veins (figs. 3a, b). these alterations appear as symmetrical narrow (up to few cm thick) bleached table i: summarized list of abbreviations of minerals used (after siivola & schmid, 2007). mineral abbreviation albite ab adularia adu biotite bio calcite cal chalcopyrite ccp chlorite chl clinozoisite czo diopside di epidote ep galena gn hematite hem k-feldspar kfs muscovite mu pentlandite pn pyrite py pyrrhotite po prehnite prh rutile rt sericite ser sphalerite sp titanite ttn geologia croatica 63/1geologia croatica 80 margins beside thin veins and broad alteration bands along thick veins where epidotization and chloritization of the adjacent rock are recognizable. the following mineralogical characteristics were observed from the veins toward the unaltered wall rocks. very close to the vein wall (in a 2–5 mm thick band) the feldspar porphyroblasts (albite) exhibit a turbid appearance because of micro-sized pores (<2 μm fl uid inclusions), that fi ll the entire grain (fig. 4a, c). the micas (muscovite+biotite) of the unaltered wall rock found among feldspar porphyroblasts are totally replaced by albite. these albite pseudomorphs form elongated grains with irregular grain boundaries (fig. 4a) and frequently contain tiny euhedral titanite inclusions (fig. 4b). in both the albite pseudomorphs and in the albite porphyroblasts, small (<0.5 mm) cavities occur in signifi cant amounts. euhedral albite crystals have frequently fi gu re 3: typical symmetrical wall-rock alteration patterns along propylitic veins. a) symmetrical bleached margin along vcpx-ep vein (wall-rock: biotite gneiss); b) symmetrical bleached margin along vep-chl vein (wall-rock: chloritic two-mica gneiss) fi gu re 4: alteration mineral assemblages in the margin closest to the veins. a) irregularly bordered elongated albite pseudomorph after mica (+n); b) group of euhedral titanite inclusions in an albite pseudomorph (1n); c) euhedral albite crystal growth in a cavity fi lled by epidote, (note the many micro pores in albite) (1n); d) well developed growing zonation in a cavity fi lling epidote crystal (1n) a b a b c d fintor et al.: near vein metasomatism along propylitic veins in the baksa gneiss complex, pannonian basin, hungary geologia croatica 81 grown on the walls of the cavities (fig. 4c). the cavities are fi lled with epidote that often shows a characteristic zoned growth pattern (fig. 4d). the alteration mineral paragenesis of this domain is: ab + ttn±ep towards the wall rock the amount of albite pseudomorphs after micas markedly decreases. the amounts of micropores observable in the albite porphyroblasts also gradually decreases. small patches of sericite inclusions appear in the feldspar crystals and their amount progressively increases towards the wall-rock. epidote and chlorite replacement after biotite become dominant in the altered domains of the wall-rock (fig. 5a–f). well developed epidote and chlorite pseudomorphs occur in the formerly mica rich bands (fig. 5a). among the epidote and chlorite pseudomorphs, euhedral titanite crystals frequently occur (fig. 5b). elongated cavities in the strongly epdotized metapelites, are some times fi lled by very fi ne grained epidote (fig. 5c). nevertheless epidote occurs as hypidiomorphic inclusions in chlorite along the cleavage (fig. 5d). in some places, anhedral epidote aggregates “fl oat” in a chlorite rich matrix (fig. 5e) together fi gu re 5: alteration mineral assemblages from the most epidotized and chloritized parts of the margin. a) epidote and chlorite pseudomorphs after biotite (+n); b) euhedral titanite crystal among a mass of replacement epidote and chlorite (1n); c) elongated cavities fi lled by fi ne grained epidote crystals in a chlorite matrix (1n); d) epidote pseudomorphs as inclusions in chlorite replacing biotite (1n); e) fi ne grained anhedral epidote aggregates among chlorite and quartz rich bands along schistosity (1n); f) subhedral elongated epidote crystals among fi ne grained anhedral epidote (1n) a b c d e f geologia croatica 63/1geologia croatica 82 with anhedral fusiform quartz grains. here, epidote shows strongly dissolved surfaces and is composed of very fi ne epidote grains (fig. 5f). among the little grains, elongated hypidiomorphic, almost clear epidote crystals are observable (fig. 5f). the alteration mineral paragenesis is: ep + chl + ttn + ab ± ser. towards the unaltered wall-rock, the amount of epidote replacing biotite decreases and chloritization of biotite becomes characteristic. furthermore, increasing numbers of biotite relics can be observed in the chloritized domains (figs. 6a, b). titanite is almost totally absent from this area, but acicular sagenite rutile inclusions can occasionally be observed in the chlorite pseudomorphs (fig. 6c). muscovite does not show any alteration except for minor sericitic recrystallization at some places. the alteration mineral paragenesis is: chl + ep + ser + rt ± ttn. in the unaltered wall rock part of the alteration zones, sericite is the major alteration mineral. it occurs as tiny lamellar inclusions in feldspars, and frequently forms sericitic rims around the clear cores of feldspar grains (fig. 6d). micas show a fresh appearance except for partially chloritized biotite fl akes. epidote occurs only as a cavity fi lling mineral phase, which frequently occurs, even in the unaltered wallrock far from alteration zones. alteration mineral paragenesis in this domain is: ser ± chl. 4.2. element maps and bulk rock chemistry element distribution maps were made from the veins and their adjacent environments including alteration halos and unaltered wall-rocks of gneiss and mica schist (fig. 7). the results show that characteristic element distribution patterns can be observed along the studied veins. based on x-ray maps, the most characteristic distribution patterns can be observed in the case of si, fe, ca, k, and ti in the veins and their immediate environments (fig. 7). bulk rock analyses made from domains show individual alteration parageneses. results are summarized in table ii where the numbers in brackets (1 to 4) on the head of the columns refer to the different domains (show individual mineral parageneses), from vein to wall rock. the results of bulk rock chemical analyses (table ii) support the estimations from element maps. besides the obvious differences between margins and unaltered wall-rock, with regard to their composition (wt %), the rock density data show that the bulk rock density markedly increases from the veins toward the adjacent rocks (table ii). 4.3. fluid inclusion petrography and microthermometry analyses were made of fl uid inclusions from cavity fi lling epidote (fig. 4d) and elongated epidote crystals that occur fi gu re 6: alteration mineral assemblages in the margin closest to the unaltered wall-rock. a) chlorite rich band with muscovite in the strongly chloritized domains (+n); b) chloritization and epidotization of biotite (1n); c) acicular rutile inclusions in chlorite pseudomorph after biotite (1n); d) sericitization of feldspar, albite crystal core with a well developed sericite crown (+n) c d a b fintor et al.: near vein metasomatism along propylitic veins in the baksa gneiss complex, pannonian basin, hungary geologia croatica 83 among fi ne grained epidote aggregates (fig. 5f). the four selected samples originated from 80.6 m, 436.2 m, 730 m, and 858.8 m depths in the drillhole. in cavity fi lling epidote grains (fig. 8a), four types of fl uid inclusion assemblages (fia) can be distinguished based on fl uid inclusion petrography. a group of fl uid inclusions composed of solitary two phase (l+v) liquid dominant fl uid inclusions occur randomly, or in small clusters in the host crystals (figs. 8b, c). their longest dimension is 5–10 µm. they are not related to growth zones of the host mineral and can not be found along cleavage planes or microcracks. defi nitive evidence for their primary origin is the occurrence of fl uid inclusions along growth zones (goldstein & reynolds, 1994; bodnar, 2003). less conclusive is the occurrence of one, or a few inclusions, in the interiors of the minerals (bodnar, 2003) as is the case for the aforementioned group of inclusions. these inclusions are considered to be primary based on their distribution within the crystal (bodnar, 2003). based on phase volume ratios, two primary fias, a p1 with fi gu re 7: x-ray element maps about a vein with characteristic symmetrical margins (3d surfaces were constructed by surfer 8), where relief and colour intensity represent the relative concentration of the diff erent elements. bar scale is 1 cm. table ii: whole rock chemical data from the margins and the unaltered wall-rock. numbers 1 to 4 in brackets at the head of the columns refer to domains characterized by individual alteration mineral paragenesis. legend: (1) ab+ttn±ep; (2): ep + chl + ttn + ab ± ser; (3): chl + ep + ser + rt ± ttn; (4): ser ± chl, abbreviation ua refer to unaltered. oxides (wt%) 637 (1) 637 (2) 637 (3) 637 (4) 637 ua (average of 4 measurements) sio2 68.81 63.53 64.80 60.59 60.59 tio2 0.95 0.88 0.85 0.91 0.88 al2o3 17.65 18.09 19.19 19.05 19.07 fe2o3 1.15 1.48 2.10 5.47 7.21 mno2 0.13 0.15 0.17 0.23 0.37 mgo 0.00 0.26 0.78 1.33 1.09 cao 4.25 4.09 3.84 4.07 2.10 na2o 6.07 8.99 4.63 5.43 5.23 k2o 0.31 1.72 2.98 2.27 2.70 p2o5 0.43 0.57 0.41 0.38 0.56 total 99.75 99.75 99.76 99.74 99.78 density (g/cm3) 2.67 2.65 2.72 2.76 2.77 geologia croatica 63/1geologia croatica 84 fi gu re 8: results of fl uid inclusion studies: a) cavity fi lled by epidote and euhedral albite crystallised cloase to the cavity wall (+n); b) schematic sketch of the distribution of diff erent fl uid inclusion assemblages in the cavity fi lling epidote; c) primary fl uid inclusion assemblage in a cavity fi lling epidote (1n); d) pseudo secondary fl uid inclusion assemblage in cavity fi lling epidote (1n); e) schematic sketch of the appearance and distribution of diff erent fia in the subhedral epidote grains that can be found among fi ne grained epidote; f) primary fl uid inclusion in subhedral elongated epidote grain (1n); g) histograms of th values of each fia; h) th vs tm(ice) plot of each investigated fia. c d a b e f g h fintor et al.: near vein metasomatism along propylitic veins in the baksa gneiss complex, pannonian basin, hungary geologia croatica 85 higher (φvap= 0.3–0.45) and a p2 with lower (φvap~ 0.15) degree of fi lling values were distinguished (table iii), although their relative ages cannot be determined. fluid inclusions of both assemblages contain an aqueous electrolyte solution without any detectable volatile content based on raman data. because eutectic melting (te) could not be determined in the inclusions, the chemical composition was not ascertainable. salinity is expressed using the mass% eq. principle (naden, 1996). in the p1 assemblage the tm(ice) values are very similar; all measured values are between –1 and –0.4 °c (n=10) (fig. 8h; table iii) indicates low salinity (0.4–1.6 mass% eq. nacl) (table iii). homogenization temperatures are with in the 303–364 °c (n=10) range (fig. 8g, h; table iii). in the p2 fia the tm(ice) values vary between –0.8 and –0.3 °c (n=6) (fig. 8h; table iii) indicating low salinity between 0.2 and 1.2 mass% eq. nacl, while th values occur in a narrow range between 201 and 214 °c (n=6) (fig. 8g, h; table iii). fluid inclusions also occur along planes that do not reach the grain boundary of the host crystals (fig. 8b). their longest dimension is 5–10 µm containing liquid and vapour phases (l+v), and show a liquid dominant (φvap= 0.4–0.45) character (table iii). we regard these inclusions as pseudosecondary (ps) based on criteria after bodnar (2003). in the ps assemblage the tm(ice) values have a very narrow range around –0.8 °c (n=6; salinity: ~ 1 m% eq. nacl; fig. 8h; table iii), while th values are between 344 and 361 °c (n=6) (figs. 8g, h; table iii). healed microcracks can be found in some parts of the host epidote, and these cracks run through the whole grains (fig. 8b). fluid inclusions occurring along these healed cracks are very small (less than 3µm), they contain one phase liquid (φvap ~ 0) (table iii) and are defi nitely secondary in origin. they are not appropriate for microthermometry. in the elongated epidote crystals that occur in the fi ne grained epidote matrix (fig. 5f.), two fl uid inclusion assemblages can be observed (fig. 8e). two phase (l+v) liquid dominant (φvap ~0.1) aqueous inclusions, with elongated shapes (fig. 8f; table iii) can be found in the crystals. their longest dimensions are in the 5–15 μm range, and although they are not concentrated in a particular growth zone, their elongation in the direction of crystallographic b-axis of epidote (fig. 8e) indicates formation during crystal growth (klemd, 2004). based on these considerations, the inclusions are most probably primary in origin and denominated as p3. the measured tm(ice) values of fl uid inclusions of p3 are between –0.1 and –0.9 °c (n=9) (fig. 8h; table iii) indicating a low salinity fl uid (0.2–1.4 mass% eq. nacl; table iii). the homogenization temperatures are in the 163–186 °c (n=9) interval (figs. 8g, h; table iii). small (<3 μm), aqueous one phase (l), irregularly shap ed inclusions can be found along trails which crosscut the entire crystals. these inclusions are secondary ones (s) in origin (table iii). they occur in subordinate amounts and they are inappropriate for microthermometry. 5. discussion 5.1 metasomatism of the wall-rock the occurrence of the same modifi cation of wall-rock from narrow symmetrical margins along thin veins to wider altered domains is observable. different types of wall rock alterations along veins have been studied in detail by many researchers (scherban, 1996; omel’yanenko, 1978; scherban, 1975; korzhinskii, 1946). occurrence of symmetrical alteration rims around veins is typical feature of so called “near vein metasomatism” (zharikov et al., 2007). metasomatic zones (zharikov et al., 2007) are denominated as zone 1 to zone 4 (zone 1 represents the closest and zone 4 the farthest domain from the vein), and can be assigned on the basis of the individual mineral paragenesis of the altered domains. the metasomatic column (metasomatic facies) (zharikov et al., 2007) is built up by the following zones: zone 1: in this zone albite and titanite are the most characteristic minerals, mineral paragenesis: ab + ttn ± ep. zone 2: here, the appearance of epidote pseudomorphs after biotite fl akes is the most characteristic alteration feature. mineral paragenesis is ep + chl+ ttn + ab ± ser. zone 3: the amount of epidote markedly decreases and the chlorite content increases. sericite is more common and rutile inclusions in chlorite frequently occur. the mineral paragenesis is chl + ep + ser + rt ± ttn. zone 4: sericitization is the most characteristic alteration process in this zone; other alteration minerals are in subordinate amounts. the mineral paragenesis consists of ser ± chl. whole rock chemical changes during metasomatic alteration of the wall-rock to alteration halos were evaluated by grant’s (1986) method using the whole rock chemical table iii: summary of the results of the fl uid inclusion study. host mineral type number of inclusions phases (25 °c) φv th (°c) v→l tm(ice) (°c) salinity nacl eq. mass % cavity fi lling epidote p1 10 l+v 0.3–0.45 303–364 –0.7±0.3 0.4–1.6 ps 6 l+v 0.4–0.45 344–361 ~–0.8 ~1 p2 6 l+v ~0.15 201–214 –0.55±0.25 0.2–1.2 s – l – – – – elongated epidote crystals p3 9 l+v ~0.1 163–186 –0.5±0.4 0.2–1.4 s – l – – – – geologia croatica 63/1geologia croatica 86 data (table ii). isocon diagrams were constructed to compare the alteration halo with the unaltered wall-rock. isocon analyses were undertaken using whole rock chemical data of the different metasomatic zones detailed above. this procedure resulted in four isocon diagrams labelled from zone 1 to zone 4 (fig. 9a.). in order to defi ne the best fi t isocon, tio2 was used as an inert constituent for each isocon diagram. titanium can be found in the altered domains as titanite and/or rutile in the pseudomorphs after biotite fl akes, indicating that the ti content of the wall rock was not changed during the alteration process (fig. 7; table ii). the most obvious characteristics of each isocon diagram are the signifi cant gain of cao in the alteration halo relative to the wallrock. the amount of the gain is almost identical from the vein to the unaltered wall-rock (figs. 9b, c, d, e). the contents of sio2, al2o3, na2o and p2o5 behave very conservatively. they do not show any signifi cant change except for a minor gain of sio2 (figs. 9b, c, d) and na2o close to the vein (fig. 9b) and a minor loss of al2o3 (fig. 9b). characteristic losses can be detected in concentrations of fe2o3, mgo, mno, and k2o. the fe2o3 and mno behave similarly; their concentrations decrease gradually from wall-rock towards the vein, except closest to the wall rock where minor differences are observable. (fig. 9b, c, d, e). the mgo content shows an intensive decrease towards the vein and only a little gain closest to the wall-rock. signifi cant loss of k2o can be observed in the alteration halo (fig. 9b, c, e), but a minor gain is detectable close to the unaltered wall-rock (fig. 9d). comparison of the results of the textural observations and isocon analyses may contribute to a better understanding of those processes that induced the characterized alteration patterns in the baksa gneisses. fi gu re 9: isocon diagrams of an altered domain occur along propylitic veins. where co refers to the concentration before, while cf refers to the concentration after alteration. a) isocon diagram of metasomatic zone 1; b) isocon diagram of metasomatic zone 2; c) isocon diagram of metasomatic zone 3; d) isocon diagram of metasomatic zone 4. cm (dashed line) indicates constant mass-, while cv (dotted line) the constant volume line on the diagrams. a b c d fintor et al.: near vein metasomatism along propylitic veins in the baksa gneiss complex, pannonian basin, hungary geologia croatica 87 the most signifi cant alteration that occurs in great abundance from narrow margins along thin veins to massive alterations of wall-rocks, are epidotization and chloritization of biotite. in some places, albite replacement after micas is also characteristic. in order to better explain the alteration processes, we present the most signifi cant element mass changes as a function of the original mass (fig. 10). here, the relative mass changes of elements (mi f-mi o)/mi o) are represented as a function of distance from propylitic veins. in the immediate few mm of the veins (fig. 10, zone 1), micas (muscovite+biotite) are totally or partially replaced by albite (fig. 4a). this phenomenon is most probably due to hydrothermal leaching that almost totally removed k, fe, mn, and mg, from these areas (figs. 9b, 10/zone 1). simultaneous to the decomposition of micas, albite crystals of the wall-rock were dissolved by the fl uid and were recrystallised in place of the micas. using known compositions of reagent minerals (árkai et al., 1999; fintor, 2005) a relevant reaction equation (1) can be formulated based on constant al: k na mg fe al al ti si o oh muscovi 1.7 0.3 0.12 0.1 3.7 1.8 0.06 6.2 20 4( ) ( ) tte k na mg fe al al ti si o oh bioti 0.9 0.1 2.1 2.5 0.9 2.7 0.2 5.3 20 4 + ( ) ( ) tte sio quartz 1.087 ca 7.043 na 4.052 h 8.27 na 2 2 + + + ++ + + 12 743. 00.9 0.1 1.1 2.9 8 5 ca al si o albite 0.26 catisio titanite 2.6 k 2 + + ++ ..6 fe mg 6.026 h o 2 2 2 + ++ +2 22. several researchers (e.g. rubenach, 2005; holness, 2003; engvik et al., 2008; dolejš & wagner, 2008) demonstrated that replacement of micas, (primarily muscovite and biotite) by albite, owing to fl uid infi ltration can play a signifi cant role in alteration of crystalline rocks. the hydrothermal solution ensured ca2+ transport in the alteration zone (fig. 10, zone 1), and ca2+ could be preserved as groups of small titanite crystals in the replacement albite or could be incorporated into albite. the appearance of titanite indicates that the ti content of biotite was immobile during hydrothermal leaching. farther away from the veins, epidotization of biotite became dominant due to the ca2+containing fl uid infi ltrating the wall-rock. the continuous ca addition in the whole altered zone is evidenced from fig. 9, and 10. epidotization of biotite releases k+ and mg2+ ions that were removed by the hydrothermal fl uid (fig. 9c, 10/ zone 2). signifi cant depletion of fe (fig. 10, zones 1–3) indicates that during epidotization of biotite, a certain amount of iron had been removed by the fl uid as fe2+. the small euhedral titanite grains that occur around and inside replacive epidote indicate that formation of epidote could not consume all of the ca2+ transported by the fl uid, hence ca2+ was in excess during metasomatism of the wall-rock (fig. 10). in addition, titanite also contains si, i.e. a certain amount of silica must also have been released from biotite during the alteration. knowing the composition of all initial reactants and fi nal products, the following reaction equation (2) can be constructed (biotite from árkai et al., 1999; epidote from fintor, 2005): k na mg fe al al ti si o oh biotite 1.9 0.1 2.1 2.5 0.9 2.7 0.2 5.3 20 4( ) ( ) + 3.. . . . . 33 1 2524 1 5652 2 2 2 3 0 7 12 ca h ca al fe si o oh epidote 0.2 3 + ++ ( ) + catisio titanite fe 2.1 mg 1.9 k na 5 2+ + + + + + + + + 1 4044 0 1 0 4 2. . . 0044 1 0348h sio (aq) h o4 4 2+ . epidotization of biotite is a well-known process especially in metasomatic alterations caused by granitic and granodioritic intrusions (e.g. jacobsen & mccarthy, 1976; singleton, 1979; klemd & barton, 1988; šarič, et al., 2009). from comparison of the former equation with fig. 10 (zone 2), it is obvious that not all of the potassium had been removed from this part of the vein margin. it is likely that this defi cit most probably resulted from muscovite that had not suffered epidotic or chloritic alteration and its replacement by albite became weak in the zone 2. however, sericitization became more intensive from zone 2, and a signifi cant amount of potassium that was released during dissociation of biotite could be incorporated into sericite. towards the unaltered wall-rock, epidotization became less effective and chloritic alteration became predominant. in a few locations of this region chlorite-pseudomorphs contain fi gu re 10: diagram representing the relative mass changes of elements in order of these elements original mass as a function of distance from the propylitic veins. dotted horizontal line at zero value indicate tio2 as the inert (constant mass) constituent. geologia croatica 63/1geologia croatica 88 sagenite rutile inclusions, which support the immobility of titanium in the altered rocks, but indicate that calcium and silica were insuffi cient to form titanite in these domains. the mg content in this zone (fig. 10/zone 3) increases most obviously due to the predominance of chlorite and a lesser epidote content. the signifi cant increase in the potassium content (fig. 10 zone 3) can be attributed to more factors. sericitization is the most intensive in this zone; while muscovite is almost unaltered in this part of the alteration zone, except for minor sericitic recrystallization. although chloritization of biotite is very intensive towards the unaltered wall-rock, more and more unaltered biotite relics occur in the chloritized domains that also conserve potassium. in zone 4, those components that display the most signifi cant mass depletion elsewhere (fig. 10, zones 1–3) reach their mass values characteristic of the unaltered wall-rock (fig. 10, zone 4). here, the major alteration mineral is sericite with a few chlorite fi lled cavities. the high ca-content (fig. 10, zone 4) of the zone is most probably due to the presence of cavity-fi lling epidote, which occurs very frequently in the alteration zones, and in the unaltered wall-rock. 5.2. palaeohydrology the euhedral albite crystals on the cavity walls, and the welldeveloped growth zonation of the cavity fi lling epidote (fig. 4d), indicate that these minerals precipitated in an open space system. the secondary porosity was most probably caused by hydrothermal leaching of the circulating fl uid, which is one of the most effective processes in the metasomatic regime (putnis, 2002). effective leaching is supported by the signifi cant turbidity of feldspars in the altered margins, because this texture can develop by fl uid infi ltration (parsons & lee, 2000; walker et al., 1995). the primary (p1, p2) and pseudosecondary (ps) fl uid inclusions of cavity fi lling epidote, display a uniform physicochemical character, which is a dilute aqueous-electrolyte solution without any volatile components. both the composition (0.2–1.6 mass% eq. nacl) and the range of th values (200–360 °c) indicate a fl uid identical to that found in the primary fl uid inclusions of vein fi lling diopside (0.7–2.9 eq. mass % nacl, th: 308–362 °c), and epidote (0.2–1.2 eq mass% nacl, th: 206–359 °c), of the ca-al-silicate veins (fintor et al., 2009) that are bordered by the metasomatised zone. based on the previous assumptions, it could be stated that an interconnected cavity system existed in the margins that was in connection with the veins. hence the migrating fl uid penetrated the cavity system resulting in epidote precipitation. although the chemical character of the p3 assemblage (0.2– 1.4 mass% eq. nacl), indicates a similar fl uid type to that found in p1 and p2, the lower th values (160–200 °c) indicate that trapping of this fl uid type occurred later than the main phase of hydrothermal alteration. taking into consideration that any unambiguous evidence for heterogeneous entrapment, or post-entrapment modifi cations of inclusions, including leakage/refi lling or irreversible change of inclusion volume etc. could not be found, the wide th range (200– 364 °c) may be explained by subsequent entrapment of primary and pseudosecondary fi in a cooling hydrothermal fl uid regime. such an important drop in temperature (~200 °c) that can be observed between p1 (th: 303–364 °c) and p3 (th: 160–200 °c) assemblages, can be imagined if the heat effect of an immediate magmatic source caused a short lived fl uid fl ow with a very low fl uid/rock ratio and the ambient rock temperature was ~180 °c. the existence of an interconnected fl uid circulation regime between the veins and the metasomatized domains indicates that the same pressure conditions (~88 mpa, fintor et al., 2009), which were established in the case of the ca-al-silicate veins, can be applied in the case of fl uids migrating into the cavities. based on this approach, the trapping temperature of fl uid that entered the rock mass was in the 250–480 °c range similar to that which could have been observed in the ca-al-silicate veins (fintor et al., 2009). this is in accordance with such a kind of alteration in a hydrothermal metasomatic regime (robb, 2005). based on the observed mineral paragenesis, the estimated temperature range and the type of element mobilization, the studied alteration process belongs to the propylite metasomatic family based on the nomenclature of zharikov et al. (2007). as chemical compositions of pyrite in both the pure sulphide veins (tarnai, 1998) and the caal-silicate veins is identical concerning the co/ni ratio (fintor et al., 2009), both vein types were formed due to postmagmatic hydrothermal processes and the studied veins represent real propylites. according to the “t-qualitative ph diagram” of metasomatic families (fig. 11) (zharikov et al., 2007), propylite is stable around ~260–410 °c temperature and ~4.5–7 ph range, (grey shaded area on fig. 11). as the dissociation of water is also temperature dependent, the neutral ph value becomes 5 at around 250 °c. hence the fi gu re 11: diagram illustrating a fragment of the general t-qualitative ph fi elds of the metasomatic families (modifi ed after zharikov et al., 2007). the dot-dash line separates acidic and neutral alkaline-alkaline families (with and without quartz). dashed lines indicate the possible temperature range of the metasomatic alteration. the grey shaded fi eld represents the possible metasomatic family indicated by mineral paragenesis. the hatched area indicates a metasomatic paragenesis without quartz. (aeg-am metasomatic rock refers to aegirine-amphibolite metasomatic rock; qtz-fp m–r* refer to quartz-feldspar metasomatic rock). fintor et al.: near vein metasomatism along propylitic veins in the baksa gneiss complex, pannonian basin, hungary geologia croatica 89 observed mineral assemblage is stable at neutral-weakly alkaline conditions, which is in good agreement with observations in many other fl uid-rock interaction systems where albite, epidote, and chlorite are stable (bird et al., 1984; giggenbach, 1981; bird & helgeson, 1980). the total lack of a quartz phase in the metasomatic column indicates that the peak temperature condition of alteration was above ~340 °c, because quartz free propylite only exists at the 340–400 °c temperature range (zharikov et al., 2007) (hatched area on fig. 11). this estimation is coherent with the fl uid inclusion microthermometry data. we can ascertain from the observed characteristics that the fl uid circulated in propylitic veins (fintor et al., 2009), and caused signifi cant propylitic alteration in the adjacent rocks. the composition of the metasomatic column can be summarized as ab+ep+chl+ttn+rt+ser. the same phases can be found inside the propylitic veins (fintor et al., 2009). the indications of sulphide ores in the studied well (tarnai, 1997; 1998), and the similarities of the observed propylitic metasomatite with other fi elds where signifi cant ore mineralization is associated with this type of alteration (kulikova et al., 2007; tassinari et al., 2008; abia et al., 2003) indicates further investigation of the area. 6. conclusions 1. the fl uid circulated in the propylitic veins and caused metasomatism of the wall-rock with transport of considerable amount of ca2+ toward the adjacent rocks. the hydrothermal leaching almost totally removed the k, fe, mg, and mn basic ion content of the wall rock. 2. the characteristic mineral parageneses of individual metasomatic zones of the metasomatic column indicate that the altered wall rock is related to the propylite metasomatic family. the combined mineral assemblage of the metasomatic column is: ab+ep+chl+ttn+rt+ser. 3. the pervasive hydrothermal leaching in the wall-rock resulted in signifi cant volume loss and secondary porosity in the altered domains. the fl uid migration took place not only in the veins but also in the margins along them, and penetrated a great distance into the adjacent rocks along interconnected cavities. 4. the peak temperature range of the metasomatism was around 360–480 °c, and the alteration occurred as a result of a near neutral, or weakly alkaline hydrothermal solution. 5. the similarities of the studied propylitic mineral assemblages (both in the veins and in the wall-rock) with those that are characteristic in the case of many hydrothermal ore deposits, indicates further research in this topic would be useful. acknowledgement the authors would like to thank the hungarian research fund (no. k60768) for providing fi nancial support. the authors also would like to thank to vesnica garašić, ferenc molnár and an anonymous reviewer for their very useful and detailed reviews which contributed to the improvement of the fi nal draft of the article. special thanks go to sándor kaczur for his help during conversion of the raw element map data and to the american journal experts for detailed grammar checking of the manuscript. references abia, e.h., nachit, h., marignac, c., ibhi, a. & saadi, a.s. (2003): the polymetallic au–ag-bearing veins of bou madine (jbel ougnat,eastern anti-atlas, morocco): tectonic control and evolution of a neoproterozoic epithermal deposit.– journal of african earth sciences, 36, 251–271. árkai, p. (1985): polymetamorphic evolution of the south-hungarian crystalline basement, pannonian basin: geothermometric and geobarometric data.– acta geologica hungarica, 3–4/23, 165–190. árkai, p., horváth, p. & nagy, g. (1999): a clockwise p–t path from the variscan basement of the tisza unit, pannonian basin hungary.– geologica croatica, 2/52, 109–117. bakker, r.j. (2003): package fluids 1.computer programs for analysis of fl uid inclusion data and for modeling bulk fl uid properties.– chemical geology, 194, 3–23. bird, d.k., schiffman, w., elders, w.a., williams, a.e. & mcdowell, d.s. (1984): calc-silicate mineralization in active geothermal systems.– economic geology, 79, 671–695. bird, d.k. & helgeson, h.c. (1980): chemical interaction of aqueous solutions with epidote-feldspar mineral assemblages in geologic systems i. thermodynamic analysis of phase relations in the system cao-feo-fe2o3-al2o3-sio2-h2o-co2.– american journal of science, 281, 907–941. bird, d.k. & helgeson, h.c. (1981): chemical interaction of aqueous solutions with epidote-feldspar mineral assemblages in geologic systems ii. equilibrium constraints in metamorphic/geothermal processes.– american journal of science, 281, 576–614. bodnar, r.j. (2003): introduction to fl uid inclusions.– in: samson, i., anderson, a. & marshall, d. (eds): fluid inclusions: analysis and interpretation. vancouver, mineralogical association of canada, 1–8. coelho, j. (2006): geoiso-a windowstm program to calculate and plot mass balances and volume changes occurring in a wide variety of geologic processes.– computers & geosciences, 32, 1523– 1528. de capitani, c. & brown, t.h. (1987): the computation of chemical equilibrium in complex systems containing non-ideal solutions.– geochimica et cosmochimica acta, 51, 2639–2652. de capitani, c. (1994): gleichgewichts-phasendiagramme: theorie und software.– beihefte zum european journal of mineralogy, 72. jahrestagung der deutschen mineralogischen gesellschaft, 6, 48. diamond, l.w. (2003): systematics of h2o inclusions.– in: ian samson, alan anderson, & dan marshall (eds): fluid inclusions: analisys and interpretation. vancouver, mineralogical association of canada, 55–77. dolejš, d. & wagner, t. (2008): thermodynamic modeling of non-ideal mineral-fl uid equilibria in the system si-al-fe-mg-cana-k-h-o-cl at elevated temperatures and pressures: implications for hydrothermal mass transfer in granitic rocks.– geochimica et cosmochimica acta, 72, 526–553. engvik, a.k., putnis, a., fitz gerald, j.d. & austrheim, h. (2008): albitization of granitic rocks: the mechanism of replacement of oligoclase by albite.– the canadian mineralogist, 46/6, 1401–1415. fazekas, v. & vincze, j. (1991): hidrotermás ércindikációk a villány-hegység északi előtere mélyfúrásaiban [hydrothermal ore indications in the boreholes of the northern foreground of villány mountains – in hungarian)].– földtani közlöny, 91/1–4, 23–56. geologia croatica 63/1geologia croatica 90 fintor, k. (2005): az epidotosodás vizsgálata a baksai komplexum képződményeiben [analysis of epidotization in the rock body of the baksa complex – in hungarian].– msc thesis. universitiy of szeged, szeged, 66 p. fintor, k., schubert, f. & m. tóth, t. (2008): hiperszalin paleofl uidum áramlás nyomai a baksai komplexum repedésrendszerében. [indication of hypersaline paleofl uid migration in the fracture system of the baksa complex – in hungarian].– földtani közlöny, 138/3, 257–278. fintor, k., m. tóth, t. & schubert, f. (2009): a baksai komplexum posztmetamorf fl uidum evolúciója [post-metamorphic fl uid evolution of the baksa complex – in hungarian].– in: m. tóth, t. (ed): magmás és metamorf képződmények a tiszai egységben.– geolitera, szeged (in press). gary, m., mcafee, r. & wolf, c.l. (1974): glossary of geology. – american geological institute, 805 p. géczy, b. (1973): plate tectonics and paleogeography in the east-mediterranean mesozoic.– acta geol. hung., 27/379–389. giggenbach, w.f. (1981): geothermal mineral equilibria.– geochimica et cosmochimica acta, 45, 393–410. goldstein, r.h. & reynolds, t.j. (1994): systematics of fl uid inclusions in diagenetic minerals, sepm short course 31, tulsa, oklahoma, society of sedimentary geology, 199 p. grant, j.a. (1986): the isocon diagram – a simple solution to gresen’s equation for metasomatic alteration.– economic geology, 81/8, 1976–1982. grant, j.a. (2005): isocon analysis: a brief review of the method and applications.– physics and chemistry of the earth, 30/997–1004. gresens, r.l. (1967): composition-volume relationships of metasomatism.– chemical geology, 2, 47–65. gryaznov, o.n. (1992): ore-bearing metasomatic formations of folded belts. nedra publishing, 258 p. (in russian). haas, j. & péró, cs. (2004): mesozoic evolution of the tisza megaunit.– int. j. earth sci., 93, 297–313. holland, t.j.b. & powell, r. (1998): an internally consistent thermodynamic data set for phases of petrological interest.– journal of metamorphic geology, 16, 309–343. holness, m.b. (2003): growth and albitization of k-feldspar in crystalline rocks in the shallow crust: a tracer for fl uid circulation during exhumation?– geofl uids, 3/2, 89–102. horváth, p., kovács, g. & szakmány, gy. (2003): eclogite and garnet amphibolite pebbles from miocene conglomerates (pannonian basin hungary): implications for the variscan metamorphic evolution of the tisza megaunit.– geologica carpathica, 6/54, 355–366. jacobsen, j.e.b. & mccarthy, t.s. (1976): an unusual hydrothermal copper deposit at messina, south africa.– economic geology, 71/1, 117–130. jakob, a., mazurek, m. & heer, w. (2003): solute transport in crystalline rocks at aspo–ii: blind predictions, inverse modelling and lessons learnt from test stt1.– journal of contaminant hydrology, 61, 175–190. kassai, m. (1972): a villány-szalatnaki pleozóos mélytörés [the paleozoic deep fracture of villány-szalatnak – in hungarian].– mta x. oszt. közl., 6/1, 351–354. király, e. (1996): adalékok a délkelet-dunántúli polimetamorf aljzat megismeréséhez [new results on the research of polymetamorphic basement of south-east transdanubia – in hungarian].– földtani közlöny, 1/126, 1–23. klemd, r. (2004): fluid inclusions in epidote minerals and fluid development in epidote-bearing rocks.– reviews in mineralogy & geochemistry, 56, 197–234. klemd, r. & barton, jr.j.m. (1988): mineralogy and geochemistry of the hydrothermally altered archean granodioritic rocks of the vendersdorp dome western transvaal, south africa.– mineralogy and petrology, 38, 151–160. korzhinskii, d.s. (1946): metasomatic zonation near fractures and veins.– zapiski of all-union mineralogical society, 75/4, 321–332, (in russian). krumgalz, b.s., pogorelsky, r. & pitzer, k.s. (1996): volumetric properties of single aqueous electrolytes from zero to saturation concentration at 298.15 k represented by pitzer’s ion interaction equations.– journal of physical chemistry referential data, 25, 639–663. kulikova, z.i., spiridonov, a.m. & zorina, l.d. (2007): metasomatites of the kara gold deposit (eastern transbaikalia).– russian geology and geophysics, 48, 901–912. kullerud, k. (2000): occurrence and origin of cl-rich amphibole and biotite in the earth’s crust – implications for fl uid composition and evolution.– in: stober, i. & bucher, k. (eds.): hydrogeology of crystalline rocks. dordrecht, kluwer academic publishers, 205–226. mazurek, m., jakob, a. & bossart, p. (2003): solute transport in crystalline rocks at aspo– in: geological basis and model calibration.– journal of contaminant hydrology, 61, 157–174. meyer, c. & hemley, j.j. (1967): wall rock alteration.– in: barn es, h.l. (ed.): geochemistry of hydrothermal ore depo dits. pennsylvania, university park, holt, reinhart and winston, inc., 166–235. naden, j. (1996): calcicbrine 1.5: a microsoft excel 5.0 add-in for calculating salinites from microthermometric data in the system nacl-cacl2-h2o. pacrofi vi, university of wisconsin. omel’yanenko, b.j. (1978): wall rock hydrothermal alteration. nedra publishing, 215 p. (in russian). parsons, i. & lee, m.r. (2000): alkali feldspars as microstructural markers of fl uid fl ow.– in: stober, i. & bucher, k. (eds.): hydrogeology of crystalline rocks. dordrecht, kluwer academic publishers, 27–50. putnis, a. (2002): mineral replacement ractions: from macroscopic observations to microscopic mechanisms.– mineralogical magazine, 66/5, 689–708. ravasz baranyai, l. (1969): eclogite from the mecsek mountains, hungary.– acta geologica academiae scientiarum hungaricae, 13, 315–322. robb, j.l. (2005): hydrothermal ore forming processes. – in: robb, j.l. (ed): introduction to ore forming processes. johannesburg, black well publishing company, 129–214. roedder, e. (1984): fluid inclusions. reviews in mineralogy, mineralogical society of america, 12, 644 p. rubenach, m.j. (2005): relative timing of albitization and chlorine enrichment in biotite in proterozoic schists, snake creek anticline, mount isa inlier, northeastern australia.– the canadian mineralogist, 43, 349–366. rusinov, v.l. (1989): metasomatic processes in volcanic rocks., nauka publishing, 214 p. (in russian). šarič, k., cvetkovič, v., romer, r., l., christofides, g. & koroneos, a. (2009): granitoids associated with east vardar ophiolites (serbia, f.y.r. of macedonia and northern greece): origin, evolution and geodynamic signifi cance inferred from major and trace element data and sr-nd-pb isotopes.– lithos, 108, 131–150. scherban, i.p. (1975): conditions of low temperature wall rock metasomatites formation (on example of altai-sayan region)., nauka publishing, 197 p. (in russian). scherban, i.p. (1996): ore-bearing near-vein metasomatites. lebed’ publishing, 350 p. fintor et al.: near vein metasomatism along propylitic veins in the baksa gneiss complex, pannonian basin, hungary geologia croatica 91 siivola, j. & schmid, r. (2007): list of mineral abbreviations.– in: fettes, d. & desmons, j. (eds.): a classsifi cation and glossary of terms. new york, cambridge university press, 93–110. singleton, d.g. (1979): geology of the seward mountains, western palmer land.– british antarctic survey bulletin, 49, 81–89. szederkényi, t. (1976): barrow-type metamorphism int he crystalline basement of south-east transdanubia.– acta geol. ac. sci. hung., 20, 47–61. szederkényi, t. (1979): a mecseki ópaleozos-prekambriumi alapszelvények komplex földtani feldolgozása [complex geological evaluation of precambrian-paleozoic bore-logs in the mecsek mountain – in hungarian]. manuscript., jate, szeged, 139 p. szederkényi, t. (1983): origin of amphibolites and metavolcanics of crystalline complexes of south transdanubia, hungary.– acta geologica hungarica, 1–2/26, 103–136. szederkényi, t. (1984): az alföld kristályos aljzata és földtani kapcsolatai [crystalline basement of the great hungarian plain and its geological connections – in hungarian]. department of mineralogy, geochemistry and petrology. szeged, university of szeged, 184 p. szederkényi, t. (1996): metamorphic formations and their correlation in the hungarian part of tisia megaunit (tisia composite terrane).– acta mineralogica-petrographica, szeged, xxxvii, 143–160. tarnai, t. (1997): ore minerals from the key section of the baksa complex (w baranya hills, hungary).– acta mineralogica-petrographica, xxxviii/supplementum, 119–133. tarnai, t. (1998): mineralogical-petrological study on ore vein penetrated by the key-borehole baksa no. 2 se transdanubia, hungary.– acta mineralogica-petrographica, xxxix, 21–34. tassinari, g.c.c., pinzon, d.f. & ventura, b.j. (2008): age and sources of gold mineralization in the marmato mining district, nw colombia: a miocene-pliocene epizonal gold deposit.– ore geology reviews, 33, 505–518. walker, f.d.l., lee, m.r. & parsons, i. (1995): micropores and micropermeable texture in feldspars: geological and geophysical implications.– mineralogical magazine, 59, 507–536. zharikov, v.a., pertsev, n.n., rusinov, v.l., callegari, e. & fettes, d.j. (2007): metasomatism and metasomatic rocks.– in: fettes, d. & desmons, j. (eds.): metamorphic rocks: a classifi cation and glossary of terms. new york, cambridge university press, 58–69. manuscript received june 17, 2009 revised manuscript accepted november 10, 2009 available online february 28, 2010 geo.cro.2-3-61-kb.pdf 1 �edi to rial dear readers, you have certainly noticed that this volume of geologia croatica is rather unusual. surely it is quite thick, since it is a double issue, but also since it is the fi rst time that, besides the usual editors, geologia croatica also has a guest-editor. dr. tonći grgasović has been appointed guest editor for this volume since he is a spiritus movens of the main topic of the volume you have in front of you – fossil algae, and who was also in charge of the last year’s celebration of the 100th anniversary of the research of fossil algae in croatia. in 1907, the austrian geologist and palaeontologist richard johann schubert described the fi rst permian dasyclad – mizzia velebitana from velika paklenica on mt. velebit. in the following years, fi rst a pioneer of the research on fossil algae julius von pia, and later croatian researchers milan herak, vanda kochansky-devidé, ivan gušić, momčilo milanović and branko sokač described hundreds of algal taxa in croatia (many for the fi rst time), making a signifi cant contribution to the knowledge on fossil algae, especially those from the order dasycladales. more information about the history of this research can be found in the following pages. for the occasion of this jubilee, we invited prominent international experts to send us their contributions on the topic of fossil algae. as you can see, they have gladly responded, and we are able to present you with as many as 20 papers made by 58 authors. a signifi cant part of these contributions were presented at the “9th international symposium on fossil algae” that was organized in the occasion of the jubilee, and took place in zagreb from 19 to 20 september 2007. the main organizer of the symposium was the croatian geological survey (former institute of geology), that will celebrate its 100th anniversary in 2009. during the symposium, two fi eld-trips were organized. a pre-symposium fi eld-trip in the area of the dinaride mts. focused on permian – cretaceous calcareous algae and evolution of the shallow-water carbonate environments in the area of velebit mt. and biokovo mt. and on the recent algal biocalcifi cation in the plitvice lakes. a post-symposium fi eld-trip took place in the area of north-west croatia (medvednica mt., ivanščica mt., žumberak-samoborsko gorje mts.), and focused on triassic, miocene and palaeocene deposits with calcareous algae. the symposia represent the main activity of the “international fossil algae association” (ifaa) that gathers researchers together on the diverse topic of fossil algae. papers presented in this volume are quite diverse, both in topics and in geological ages represented. the stratigraphic range of the deposits described comprises almost the entire history of life on earth, from the precambrian to recent. various groups of microbes and algae (in the broad sense) have been described, from cyanobacteria, different green algae – dasyclads, halimedaceans, charophyta etc., red algae – corallines, solenoporaceans, to various groups of benthic calcareous algae with a problematic taxonomic position, as well as various sediments and sedimentary structures that they form, together with biological and geological processes in which they are involved. the localities investigated are scattered all over the world. many contributions are not only palaeontological, but have multidisciplinary approach, and include biostratigraphy, palaeogeography, ecology and palaeoecology, diagenesis, facies analysis, sequence stratigraphy, hydrogeology and speleogenesis. all contributions, although predominantly devoted to fossil algae, have passed the regular reviewing procedure, since this is a regular volume of our journal, geologia croatica. therefore, after “algal” papers there are two other interesting contributions regarding volcanic facies and triassic rifting in ne hungary, as well as beach sand analysis of some adriatic islands. it is our pleasure to thank numerous authors and similarly numerous reviewers that contributed to the 61 volume of geologia croatica with the hope that the steady enhancement of quality will be recognized in the impact of our journal. tonći grgasović, guest editor, mladen juračić and ivo velić, editors 100th anniversary of the research on fossil algae in croatia geologia croatica 61/2–3 49 zagreb 2008 geologia croaticageologia croatica � gc 58-1.indb 1. introduction carbonate sediments have been deposited in oceans and seas from the proterozoic up to the present day. their palaeogeographic distribution, extent and composition changed substantially through time. recent carbonate platforms are closely linked with reef constructions, but, during the past, non-reefal carbonate production played an important role in the periods of the depressed reef-growth (kiessling et al., 2003). under the term “carbonate platform” in croatia we usually consider the sedimentary environment in the karst dinarides from the late triassic up to the end of cretaceous, or even to the middle eocene. nevertheless, the first evidence of shallow-water carbonate platform sedimentation in the western part of equatorial palaeotethys is related to the late viséan (fig. 1a), with ooids, crinoids and small foraminifera as carbonate producers (velić et al., 2002; kiessling et al., 2003). equatorial shelf of the palaeozoic supercontinent – cradle of the adriatic carbonate platform jasenka sremac the late carboniferous–early permian period is defined as the lower cycle of lateto post-variscan sedimentation (krainer, 1993; aljinović & tišljar, 2001). transgressive–regressive clastic–carbonate sediments from this period reflect the eustatic sea-level fluctuations caused by the gondwana glaciation. during the upper cycle (middle–late permian to early triassic) sedimentation patterns were more uniform, with similar sedimentary sequences developed in the southern alps, eastern alps and dinarides (fig. 3) (krainer, 1993). carbonate platforms existed in the western part of equatorial and subequatorial palaeotethys (fig. 1b) (kiessling et al., 2003). terminal permian catastrophic event, although killing a high percentage of living taxa on land and in the oceans, did not cause a significant reduction of the carbonate platforms, but lower triassic platforms were formed without the contribution of reefal debris. grains and micrite on the platform were formed by the activity of disaster biota – microbes (cyanobacteria). 2. carboniferous and permian palaeogeography and climate during the late carboniferous, and especially in the permian, continental masses on earth were united in the largest continent ever existing – pangaea (figs. 1a, b, 4). this supercontinent, extending almost from pole to pole, was positioned between the giant panthalassa ocean to the west, and the smaller palaeotethys ocean to the east. at the end of the lower permian a new ocean – tethys (neotethys) was born within marginal gondwana, south of palaeotethys, extending from timor to sicily (fig. 4) (scotese & langford, 1995; stampfli et al., 2001; scotese, 2002). formation of such a large continental mass resulted in the domination of an arid continental climate and deposition of evaporites in shallow water basins. carboniferous rain forests were replaced with xerophytic vegetation, and the accumulation of organic matter significantly decreased. the low rate of precipitation diminished the erosion of land. the increased amount of co2 in the atmosphere caused the “greenhouse effect” with global warming. ice caps were melted, causing the geologia croatica 58/1 1–19 4 figs. 5 pls. zagreb 2005 key words: pangaea, palaeotethys, equatorial shelf, carbonate platform, carbonate producers, palaeozoic, croatia. department of geology and palaeontology, faculty of science, university of zagreb, ul. kralja zvonimira 8, hr-10000 zagreb, croatia; e-mail: jsremac@inet.hr abstract during the carboniferous and permian, several carbonate platforms existed along the eastern coast of the supercontinent pangaea. croatian palaeozoic carbonate sediments were produced in this “carbonate factory”. the dominant skeletal carbonate producers were calcareous algae, with assistance from foraminifera, molluscs, brachiopods and crinoids. sporadically, reef structures were built by calcisponges, bryozoans, algal and cyanobacterial encrusters. variscan and post-variscan tectonic events strongly influenced the platform existence through uplift and deposition of molasse sediments, while a global catastrophe at the permian/triassic boundary only changed the biotic carbonate producers. a significant input of terrestrial material during the lower triassic, due to uplift and/or global regression, altered the mode of sedimentation along the shallow palaeotethyan shelves. platforms were partly restored during the middle and upper triassic, and existed with short interruptions till the middle eocene. 2 geologia croatica 58/1 additional evaporation of co2 into the atmosphere. cold climate conditions were restricted to the northeastern part of the siberian land, and southern parts of australia and antarctica (barron & fawcett, 1995). this hot climate favoured carbonate sedimentation, and enabled the formation of large carbonate platforms, not only in equatorial and subequatorial regions, but also in high subtropical latitudes (fig. 1) (kiessling et al., 2003; ziegler et al., 2003). platform sedimentation took place over the wide area of the alps and dinarides (herak, 1991; kiessling, 2003), often associated with the formation of reefs, which can be found today in italy, hungary, slovenia, croatia, serbia, montenegro and greece (flügel et al., 1984; ramovš & sremac, 1986; ramovš et al., 1987, 1990; pešić et al., 1988; sremac, 2001). porous reef structures at the margin of palaeotethys and panthalassa entrapped significant amounts of oil, thus forming world famous oil-fields (texas, iran, china) (klemme & ulmishek, 2001). 3. the palaeozoic in croatia (from the deep ocean to the carbonate platform) palaeozoic sediments in croatia outcrop sporadically, often in tectonically limited belts (fig. 2). although geographically restricted, some of these localities are the treasuries of data from ancient geological history. lower palaeozoic, pre-variscan sediments of croatia were deposited in a deep marine basin, which was part of the rheic ocean. they contain fossils of pelagic biota (graptolites, conodonts) and spores, preserved despite subsequent metamorphic processes (đurđanović, 1968, 1973; sremac & mihajlović-pavlović, 1981; jerinić et al., 1994). opening of the palaeotethys ocean in the late silurian and devonian positioned this sedimentary basin between these two oceans. recent investigations have shown that shallow marine carbonate sedimentation in this area began in the early carboniferous (viséan). crinoid limestones and carbonate clasts with small foraminifera of this age were found on medvednica mt. (šikić, 1995; sremac, unpublished) and in the gorski kotar region (sremac & aljinović, 1997) (pl. 1, fig. 1). closure of some fore-arc and back-arc basins in the namurian and westphalian caused emersion of the shallow-sea environments, and infilling of basins with molasse sediments (krainer, 1993; stampfli et al., 2001). carbonate sedimentation took place contemporaneously on palaeotethyan shelf areas along the northern gondwana passive continental margin (ramovš et al., 1990; krainer, 1993; jurković & pamić, 2001; kiessling et al., 2003) (fig. 1a). fusulinids, calcareous algae and crinoids were the domfig. 1 global distribution of carbonate platforms (in black): (a) carboniferous (viséan); (b) permian (guadalupian). grey arrow shows the area where croatian palaeozoic sediments were deposited. after kiessling et al. (2003). 3sremac: equatorial shelf of the palaeozoic supercontinent... inant carbonate producers. shallow-marine carbonate sediments with microfossils of moscovian and kasimovian age (pl. 1, fig. 2), autochthonous or redeposited in younger clastic sediments, outcrop at several localities in croatia: velebit mt., gorski kotar, the banovina region, medvednica mt. (kochansky-devidé 1955, 1970; balaž, 1981; milanović, 1981; belak et al., 1995; sremac & aljinović, 1997). calcareous algae are especially abundant in these sediments, thus indicating restricted, very shallow lagoonal environments. during the late carboniferous, the first reef-building biota occurred in croatia – corals in the banovina region (kostić-podgorska, 1955) and stromatoporoids on medvednica mt. (kochanskydevidé, 1981). lower permian limestones of the rattendorf group have been found in the southern alps, velebit mt., gorski kotar region, and in clasts of younger sediments on medvednica mt. (pl. 1, figs. 3–5) (kochanskydevidé, 1959; salopek, 1960; sokač, 1973; grimani et al., 1973; sokač et al., 1976; sremac & kochansky-devidé, 1982; aljinović, 1997; sremac & aljinović, 1997; krainer, 1993). these limestones are relatively thin in the whole area of the alps and dinarides, sometimes forming lenseshaped structures within the clastic sediments. at some localities on velebit mt. continuous sedimentation from the upper carboniferous occurred. in the gorski kotar region large blocks of rattendorf limestones can sometimes be found isolated within shales (salopek, 1960). aljinović (1997) explains these phenomena by intrabasinal erosion of the partly uplifted carbonate sediments and their transportation by fan deltas down toward the steep basin slopes. numerous clasts of pelagic gzhelian to lower permian limestones with deep water radiolarians (albaillellacea), indicating water depths of over 500 m are common in the vicinity of mrzle vodice in gorski kotar. these sediments were deposited at the base of slopes along the northern active margin of palaeotethys (aljinović & kozur, 2003). in the julian alps, continuous long-lasting carbonate sedimentation began at this time (ramovš et al., 1990). carbonate sediments of the trogkofel group have been found in the gorski kotar region, within the clastic košna-conglomerates on velebit mt., and in clasts of calcareous breccias on ravna gora mt. oil exploratory-wells in zebanec (hrvatsko zagorje) and újfalu–i (hungary) also contain carbonate sediments of this age (salopek, 1960; kochansky-devidé, 1973; sokač et al., 1976; berczi-makk & kochansky-devidé, 1981; savić & dozet, 1985). at the same time, in some neighbouring areas, clastic sedimentation was dominant throughout the whole lower cycle of late to post-variscan sedimentation (krainer, 1993) (fig. 3). fig. 2 schematic map of the palaeozoic areas in croatia. after tišljar (1992) and jurković & pamić (2001) – modified. 4 geologia croatica 58/1 during the middle and/or upper permian, carbonate platform conditions were common in velebit mt., the julian alps, southern karavanke mts., carnic alps, and, finally, the dolomites. a transgression of palaeotethys from the southeast towards the northwest can be traced (ramovš et al., 1990; krainer, 1993). dolomite deposits predominate, with intercalations of limestones and evaporites. the longest period of continuous platform sedimentation can be traced in the julian alps (during the whole permian and the lowermost triassic). on velebit mt. carbonate sedimentation took place for approximately 20 million years, producing a sequence of shallow-marine carbonate sediments more than 900 m thick (kochansky-devidé, 1965; sokač et al., 1976). during detailed mapping of velebit mt. and the lika region performed by professor m. salopek and a group of his brilliant students (salopek, 1942, 1948, 1952), a rich collection of permian fossils was found. these fossils were later subject to detailed study by many croatian palaeontologists (herak & kochansky-devidé, 1960; kochansky-devidé & herak, 1960; kochansky-devidé, 1964, 1965; milanović, 1965, 1966a, b, 1968, 1974, 1975; rukavina, 1973; sremac & kochanskydevidé, 1982; sremac, 1991). the dominant carbonate producers during the middle permian were calcareous algae, dasycladales (mizzia, vermiporella, velebitella, salopekiella, connexia, likanella) or gymnocodiaceans (gymnocodium, permocalculus). benthic foraminifera were also common (staffella, nankinella, chusenella, eoverbeekina, neoschwagerina, agathammina, hemigordius), and, at some places, calcisponges, corals (waagenophyllum), molluscs (tanchintongia and other bivalves, gastropods, cephalopods), bryozoans (fenestella) and brachiopods (enteletes, martinia, productoids, oldhaminoids). reconstruction of the platform relief during the murghabian (neoschwagerina craticulifera zone) has shown that the shallowsea bottom was overgrown with calcareous algae (pl. 2, figs. 1, 2). at several places reef-building and encrusting biota (sponges, bryozoans, cyanobacteria, some brachiopods) built up mounds or patch-reefs (pl. 3, figs. 1, 2) (ramovš & sremac, 1986; sremac, 1991; marjanac & sremac, 2000). intraplatform depressions were filled with clastic material by turbidite currents (pl. 4, figs. 1, 2) (sremac, 1991). contemporaneously with the global eustatic changes (ross & ross, 1995a, b) some shallow parts of the platform were periodically emerged. vugs and cavities within the sediment, as well as cortoid grains, are reliable evidence of emersions (pl. 2, fig. 3). patch-reefs were occasionvfm? fig. 3 global eustacy curve and schematic stratigraphic framework of post-variscan sediments of the southern alps and dinarides. legend: bvc – bolzano volcanic complex; rg – rattendorf group; tg – trogkofel group; kb – košna beds; tb – tarvisio breccia; gfm – gröden formation; bfm – bellerophon formation; vfm? – velebit formation; wfm – werfen formation. after kochanskydevidé, 1973; italian research group – from krainer, 1993; ross & ross, 1995b. 5sremac: equatorial shelf of the palaeozoic supercontinent... ally buried in black muddy sediment, similar to the upper permian reefs in sichuan (china). reef-burial can be connected with oscillations of sea-level, and/or with permian anoxic events, due to the rapid warming and water stagnation in intraplatform basins. middle permian carbonate clasts have also been found in a bore-hole near rovinj (kochanskydevidé, 1967), and on medvednica mt. (devidéneděla & kochansky-devidé, 1990). at the same time, in the neighbouring gorski kotar region clastic sedimentation prevailed, with scarce limestone intercalations (“lyttonia”–limestones from križ potok) (salopek, 1960, 1961; kochansky-devidé, 1965; grimani et al., 1973; bukovac et al., 1984; savić & dozet, 1985; aljinović & sremac, 1997). the upper part of the middle permian on velebit mt. shows no major changes in the composition of sediments or fossil communities. calcareous algae and foraminifera are still the dominant skeletal carbonate producers. according to the abundance of yabeina, the yabeina syrtalis (douvillé) zone was proposed by kochansky-devidé (1965) for these limestones. the brachiopod fauna shows more distinct changes than the microfossil assemblages. new brachiopod genera (derbya, streptorhynchus, orthotetes), as well as some cephalopods (temnocheilus), occur sporadically. early diagenetic dolomites and dolomitic fossiliferous grainstones–packstones with intercalations of black mudstones and shales are the prevailing sediments (tišljar et al., 1991). middle/upper permian carbonate sediments from velebit mt. are not entirely compatible in age with the fossils and sedimentary features of the “bellerophon formation” of the southern alps. the majority of macrofossils (e.g. brachiopods) belong to the indo–armenian type of fauna, while several taxa are endemic (sremac, 1986). continental barriers between these two sedimentary basins were presumed by simić (salopek, 1942). flügel (1977 – p. 315) even proposed the category “velebit-formation” for these sediments (fig. 3). a similar development of the upper permian, named the “žažar-formation”, can be observed in slovenia (ramovš, 1958; buser et al., 1988; skaberne & ogorelec, 2003). in central and northern dalmatia and the southeastern lika regions evaporitic sediments (gypsum and anhydrite), associated with clastic and carbonate rocks and some volcanics, outcrop at several localities (fig. 2). palynological analysis suggest an upper permian age for these sediments (šušnjara et al., 1992), and they are interpreted as regressive cycles deposited in an arid climate through the progradation of sabkha environments over shallow subtidal lagoons (tišljar, 1992). according to global palaeogeographical reconstructions (krainer, 1993; stampfli et al., 2001; scotese, 2002; izart et al., 2003; kiessling et al., 2003; ziegler et al., 2003) (figs. 1 and 4) evaporites are partly related to the coastal areas of the western inactive margin of the palaeotethys ocean (dolomites, carnic alps, southern karavanke mts.), but they also occur within the shallow parts of the inner carbonate platform (e.g. central dinarides). upper permian evaporites have also been found in northwestern croatia, on samoborska gora mt. (fig. 2), in association with algal limestones (pl. 1, fig. 6) and dolomites (herak, 1956; herak & škalec, 1967). 4. permo–triassic boundary in croatia in the area of the alps and dinarides, continuous carbonate sedimentation from the uppermost permian to the triassic has been observed at several localities in the dolomites, throughout the carnic alps, southern karavanke mts., julian alps, velebit mt. and central dinarides (fig. 3). the permo–triassic boundary can be observed at several localities on velebit mt. (brušane–baške oštarije, velika paklenica) (salopek, 1942, 1952; kochansky-devidé, 1965; sokač, 1973; sokač et al., 1976; ramovš & kochanskydevidé, 1981; ramovš et al., 1990; aljinović et al., 2003). upper permian deposits on velebit mt. are in most cases represented by early-diagenetic supratidal dolomites, with intercalations of subtidal to intertidal bioclastic grainstones–packstones and lagoonal black shales. cellular dolomites (“rauchwacke”) appear occasionally in the late upper permian (tišljar et al., 1991; ibrahimpašić & sremac, 2002). uppermost permian “boundary dolomites” (sensu salopek, 1942), sometimes with parallel lamination, contain pyrite crysfig. 4 palaeogeographic map of the earth during the early permian, with the probable position of the dolomites (d), carnic alps (c), karavanke mts. (k) and velebit mt. (v). key: land – white; shallow sea – light grey; ocean – dark grey. partly after scotese & langford, 1995 – from izart et al., 2003, modified. 6 geologia croatica 58/1 tals and rare microfossils (gymnocodiaceans, foraminifera; pl. 4, fig. 4) (ramovš & kochanskydevidé, 1981; ibrahimpašić & sremac, 2002). wignall et al. (2002) describe similar sediments from china and relate them to the global anoxic event at the end of the permian. near the permo–triassic boundary, intercalations of red shale became common, and permian carbonates gradually pass into the sandy yellow-coloured dolomites of the lower triassic (salopek, 1942; sokač et al., 1976; ramovš & kochansky-devidé, 1981; tišljar et al., 1991). a similar “continuity” of sedimentation at the permo–triassic boundary has been observed in the karavanke mts. and in the vicinity of žažar and idrija in slovenia (see dolenec et al., 1999, and skaberne & ogorelec, 2003 for older references). anomalies in δ13c and δ18o represent evidence of an abrupt change in organic production and palaeotemperature (dolenec et al., 1999, 2001), thus suggesting the possibility of a sudden catastrophe (impact of an extraterrestrial object?). upper permian evaporites, carbonate and clastic rocks of central dinarides also show a continuous transition from the uppermost permian to the lower triassic (pl. 5, fig. 3) (šušnjara et al., 1992; tišljar, 1992). according to global reconstructions (scotese & langford, 1995; stampfli et al., 2001; scotese, 2002; kiessling et al., 2003; izart et al., 2003), this area was probably a shallow plateau within the carbonate platform, partly emerged during the late permian regressions, and submerged during the early triassic transgression. there are different opinions as to the age of the palaeozoic sediments and the permo–triassic boundary in the gorski kotar region. some authors (e.g. šćavničar & šušnjara, 1967; raffaelli & šćavničar, 1968) propose the continuity of sedimentation from the “upper permian” clastic sediments to the lower triassic dolomites. careful reviewing of the published papers and field investigations did not confirm this continuity, because the uppermost permian fossils have not been found in clasts (aljinović & sremac, 1997; sremac & aljinović, 1997). it is possible that this area was uplifted in the late permian, and again submerged during the early triassic transgression (pl. 5, fig. 2). a similar situation can be observed in neighbouring parts of slovenia (ramovš & kochansky-devidé, 1965; ramovš, 1968). apart from the karst region, “continuous”(?) sedimentation at the permo–triassic boundary has been observed on the samoborska gora mt. and in the banovina region. the uppermost permian in these areas is represented by clastic sediments with scattered lenses of carbonate or evaporite sediments (pl. 4, fig. 3) (herak, 1956; ramovš et al., 1990). upper permian sediments in croatia show a general shallowing upward trend, in harmony with the global eustatic curve (fig. 3), but the extreme ideas of more than 200 metres of sea-level falls could not be confirmed in this area. nevertheless, evidence of occasional emersions, such as laminar structures, stromatolites, vadose cements and highly porous carbonate breccias (“rauchwacke”), can be found in croatia from the middle permian, and, particularly in the upper permian sediments (sremac, 1991; tišljar et al., 1991; tišljar, 1992; ibrahimpašić & sremac, 2002; aljinović et al., 2003). fullerenes and shocked quartz grains, the typical impact markers, have not been found in neighbouring regions, but carbon, sulphur and strontium excursions have been confirmed at many places, including slovenia (dolenec et al., 1999, 2001). therefore sediments at the p/t boundary in croatia should be subject to isotope and microelement analysis. permian platform sediments in croatia were less affected by the p/t catastrophic event, than by tectonic movements and uplift, which caused emersion in some parts of the platform. input of terrestrial material, tectonic instability and sporadic volcanic activity were the main features during the lower and middle triassic. this area was stabilized in the late triassic, and platform sedimentation in the tethyan realm took place up to the middle eocene. 5. conclusions the first carbonate platforms in equatorial palaeotethys existed during the variscan cycle. in croatia, viséan shallow-marine fossils have been found in clasts of younger sediments. the lower part of the late to post-variscan cycle (sensu krainer, 1993) is dominantly represented by molasse sediments. clastic–carbonate sedimentation was influenced by phases of gondwanian glaciations. shallow water carbonate sediments were deposited in the late carboniferous (moscovian–kasimovian) and early permian (asselian–sakmarian). the dominant carbonate producers were calcareous algae, foraminifera and crinoids. in croatia these sediments are the most completely developed on velebit mt. middle/upper permian to lower triassic carbonate sediments of the southern alps and dinarides belong to the upper part of the late to post-variscan cycle (sensu krainer, 1993). their lateral and vertical distribution was controlled by transgression of the palaeotethys from the southeast towards the adjacent shelves. platform carbonate sediments and evaporites of this age crop out in the outer dinarides of croatia (velebit mt., croatian–bosnian border), and were also found in clasts of younger sediments (gorski kotar region), and in bore-holes (rovinj). sporadic occurrences of palaeozoic shallow water carbonate and evaporite sediments were also found in the inner dinarides (bregana, medvednica mt.). the main carbonate producers were calcareous and non-calcareous algae and foraminifera, accompanied by calcisponges, corals, molluscs, bryozoans, brachiopods and echinoderms. 7sremac: equatorial shelf of the palaeozoic supercontinent... palaeozoic rocks of croatia are in most cases in tectonic contact with the surrounding deposits, and it is impossible to estimate their original horizontal and vertical distribution. we can presume that they were deposited either on one large carbonate platform with occasionally emerged areas and intraplatform basins, or, more likely, on several smaller platforms, separated by continental or basinal barriers. during the upper palaeozoic and the lower triassic, carbonate sedimentation was interrupted by episodes of uplift, erosion and deposition of molasse sediments. phases of regression are marked by laminar structures (stromatolites), vadose cements and highly porous carbonate breccias (“rauchwacke”). an end-permian catastrophic event did not cause the collapse of the carbonate platforms, but it strongly affected the carbonate-producing biota. therefore no visible discontinuity of sedimentation can be traced at the permo–triassic boundary, and this event could only be traced through carbon, oxygen, sulphur and strontium anomalies. cyanobacteria, as the disaster taxa, are blooming around the extinction event. they are the first lithogenetic biota after the cataclysm, soon accompanied by simple, opportunistic, predominantly molluscan communities. after the phase of instability marked by clastic–carbonate sedimentation and sporadic volcanic activity, platform conditions were stabilized in the late triassic and lasted till the middle eocene. during 200 million years of existence, the palaeotethyan–tethyan “carbonate factory” produced several thousand metres of fossiliferous carbonate sediments, thus representing a palaeontological and sedimentological treasure for many generations of croatian geologists and palaeontologists. acknowledgments i express my gratitude to prof. dr. ivan gušić and the late prof. dr. jakob pamić, for their support and initial advices. dr. ivo velić and prof. dr. josip tišljar gave me the most useful suggestions on the early draft of the manuscript. dr. heinz w. kozur and prof. dr. anton ramovš improved this paper by critical reading and reviewing. dr. julie robson was responsible for careful language editing and useful comments. 6. references aljinović, d. (1997): facijesi klastičnih sedimenata mlađega paleozoika i starijega trijasa gorskoga kotara [facies of clastic sediments in late palaeozoic and early triassic of gorski kotar – in croatian].– unpubl. phd thesis, university of zagreb, 163 p. aljinović, d. & kozur, w.h. (2003): resedimented carboniferous and lower permian radiolarians in roadian (middle permian) deepwater clastic complex of gorski kotar region (croatia).– in: vlahović, i. (ed.): 22nd ias meeting of sedimentology – opatija 2003, abstracts, p. 4. aljinović, d. & sremac. j. (1997): the middle and upper permian deposits in gorski kotar: facts and misconceptions.– geol. croat., 50/2, 231–242. aljinović, d. & tišljar, j. (2001): pretplatformni megafacijesi od karbona do srednjega trijasa krškoga područja dinarida [preplatform megafacies from the carboniferous to the middle triassic in the karst area of dinarides – in croatian].– in: dragičević, i. & velić, i. (eds.): 1. znanstveni skup “karbonatna platforma ili karbonatne platforme dinarida”, zagreb 1–2. 10. 2001. knjiga sažetaka, 9–16. aljinović, d., sremac, j. & ibrahimpašić, h. (2003): permian and lower triassic facies of velebit mt. and the gorski kotar region (nw part of external dinarides).– in: vlahović, i. & tišljar, j. (eds.): evolution of depositional environments from the palaeozoic to the quaternary in the karst dinarides and the pannonian basin. field trip guidebook, 22nd ias meeting of sedimentology – opatija 2003, 185–206. balaž, e. (1981): carboniferous gastropods of lika and velebit.– palaeont. jugosl., 26 (1980/3), 1–23. barron, e.j. & fawcett, p.j. (1995): the climate of pangea: a rewiew of climate model simulations of the permian.– in: scholle, p.a., peryt, t.m. & ulmerscholle, d.s. (eds.): the permian of northern pangea. vol. 1. paleogeography, paleoclimates, stratigraphy. springer-verlag, berlin–heidelberg, 37–52. belak, m., sremac, j., crnko, j. & kolar-jurkovšek, t. (1995): paleozojske stijene niskog stupnja metamorfizma na jugoistočnoj strani medvednice (sjeverozapadna hrvatska) [palaeozoic low-metamorphic rocks at the southeastern part of the medvednica mt. – in croatian].– in: vlahović, i., velić, i. & šparica, m. (ur.): 1. hrvatski geološki kongres (first croatian geological congress), zbornik radova (proceedings), 1, 71–74. bérczi-makk, a. & kochansky-devidé, v. (1981): marine lower and middle permian in the oil exploratory well újfalu–i (sw-hungary).– acta geol. acad. sci. hungar., 24/1, 117–128. bukovac, j., poljak, m., šušnjar, m. & čakalo, m. (1984): osnovna geološka karta sfrj, 1:100000. tumač za list črnomelj l33–91 (basic geological map of sfrj 1:100000. geology of sheet črnomelj).– geol. zav. zagreb & geol. zav. ljubljana (1983), sav. geol. zav., beograd, 63 p. buser, s., grad, k., ogorelec, b., ramovš, a. & šribar, l. (1988): stratigraphical, paleontological and sedimentological characteristics of upper permian beds in slovenia, nw yugoslavia.– in: cassinis, g. (ed.): permian and permian–triassic boundary in the south alpine segment of the western tethys. mem. soc. geol. it., 34, 195–210. devidé-neděla, d. & kochansky-devidé, v. (1990): neoschwagerinen fund im medvednica-gebirge (zagrebačka gora) [findings of neoschwagerina in the medvednica mt. – in german, croatian abstract].– rad jugosl. akad. znan. umjet., 449, 29–33, zagreb. 8 geologia croatica 58/1 dolenec, t., lojen, s., buser, s. & dolenec, m. (1999): stable isotope event markers near the permo– triassic boundary in the karavanke mountains (slovenia).– geol. croat., 52/1, 77–81. dolenec, t., lojen, s. & ramovš, a. (2001): the permian–triassic boundary in western slovenia (idrijca valley section): magnetostratigraphy, stable isotopes and elemental variations.– chemical geol., 175, 175–190. đurđanović, ž. (1968): conodonten des unterdevons und unterkarbons westlich von dvor na uni (kroatien– jugoslawien) [lower devonian and lower carboniferous conodonts west from dvor na uni (croatia, yugoslavia) – in german].– geol. vjesnik, 21 (1967), 83–103. đurđanović, ž. (1973): about the paleozoic and the triassic of medvednica mountain and the area near dvor na uni on the basis of conodonts.– geol. vjesnik, 25 (1971), 29–51. flügel, e. (1977): environmental models for upper paleozoic benthic calcareous algal communities.– in: flügel, e. (ed.): fossil algae. springer-verlag, berlin–heidelberg, 314–343. flügel, e., kochansky-devidé, v. & ramovš, a. (1984): a middle permian calcisponge/algal/cement reef: straža near bled, slovenia.– facies, 10, 179–256. grimani, i., šušnjar, m., bukovac, j., milan, a., nikler, j., crnolatac, j., šikić, i. & blašković, i. (1973): osnovna geološka karta sfrj 1:100000. tumač za list crikvenica l33–102 (basic geological map of sfrj, 1:100000. geology of sheet crikvenica).– inst. geol. istraž. zagreb (1963), sav. geol. zav., beograd, 47 p. herak, m. (1956): geologija samoborskog gorja [geology of the samobor mts. – in croatian, german abstract].– acta geol., 1, 49–73. herak, m. (1991): dinaridi. mobilistički osvrt na genezu i strukturu [dinarides. mobilistic view of the genesis and structure – in croatian].– acta geol., 21/2, 35–117, zagreb. herak, m. & kochansky-devidé, v. (1960): gymnocodiacean calcareous algae in the permian of yugoslavia.– geol. vjesnik, 13 (1959), 185–196. herak, m. & škalec, d. (1967): kalkalgen im perm des samoborer gebirges [calcareous algae in the permian of the samobor mts. – in german].– geol. vjesnik, 20 (1966), 37–39. ibrahimpašić, h. & sremac, j. (2002): end permian regression – evidence from meiobenthic communities from the velebit mt. (sw croatia).– in: yanko-hombach, v. (ed.): the third. intern. congr. emmm 2002, wien, 101–103. izart, a., stephenson, r., vai, g.b., vachard, d., le nindre, y., vaslet, d., fauvel, p-j., süss, p., kossovaya, o., chen, z., maslo, a. & stovba, s. (2003): sequence stratigraphy and correlation of late carboniferous and permian in the cis, europe, tethyan area, north africa, arabia, china, gondwanaland and the usa.– palaeogeogr., palaeoclimat., paleoecol., 196, 59–84. jerinić, g., pamić, j., sremac, j. & španić, d. (1994): palynological and organic–petrographic data on very low and low grade metamorphic rocks in the slavonian mountains (northern croatia).– geol. croat., 47/2, 149–155. jurković, i. & pamić, j. (2001): geodynamics and metallogeny of variscan complexes of the dinarides and south tisia as related to plate tectonics.– nafta, 52/9, 267–284. kiessling, w., flügel, e. & golonka, j. (2003): patterns of phanerozoic carbonate platform sedimentation. lethaia 36, 195–226. klemme, h.d. & ulmishek, g.f. (2001): effective petroleum source rocks of the world: stratigraphic distribution and controlling depositional factors.– energy.er.usgs.gov/ products/papers/world_oil/aapg/bulletin/tab_01.htm. kochansky-devidé, v. (1955): karbonske i permske fuzulinidne foraminifere velebita i like i. opći dio i karbon [carboniferous and permian fusulinids of the velebit mt. and lika region. introduction and carboniferous – in croatian].– rad jugosl. akad., 305, 5–62, zagreb. kochansky-devidé, v. (1959): karbonske i permske fuzulinidne foraminifere velebita i like. donji perm. [carboniferous and permian fusulinids of the velebit mt. and lika region. lower permian – in croatian].– palaeont. jugoslavica, 3, 1–62, zagreb. kochansky-devidé, v. (1964): die mikrofossilien des jugoslawischen perms [microfossils of the yugoslav permian – in german].– paläont. z., 38/3-4, 180–188. kochansky-devidé, v. (1965): karbonske i permske fuzulinidne foraminifere velebita i like. srednji i gornji perm [carboniferous and permian fusulinids of the velebit mt. and lika region. middle and upper permian – in croatian].– acta geol., 5, 101–137, zagreb. kochansky-devidé, v. (1967): neoschwagerinenschichten einer tiefbohrung in istrien (jugoslawien) [neoschwagerina-beds from a bore-hole in istria (yugoslavia) – in german].– n. jb. geol. paläont. abh., 128/2, 201–204. kochansky-devidé, v. (1970): die kalkalgen des karbons vom velebit-gebirge (moskovien und kassimovien) [carboniferous calcareous algae from the velebit mt. (moscovien and kasimovien) – in german].– palaeont. jugoslavica, 10, 1–32, zagreb. kochansky-devidé, v. (1973): trogkofel-ablagerungen in kroatien [trogkofel beds in croatia – in german].– geologija, 16, 357–378, ljubljana. kochansky-devidé, v. (1981): karbonische stromatoporoidea und bryozoa von markuševec in medvednicagebirge [carboniferous stromatoporoidea and bryozoa from markuševec in medvednica mt. – in german].– geol. vjesnik, 34, 15–17. kochansky-devidé, v. & herak, m. (1960): on the carboniferous and permian dasycladaceae of yugoslavia.– geol. vjesnik, 13, 65–96. kostić-podgorska, v. (1955): oberkarbonische korallen von trgovska gora (croatien) [upper carboniferous corals from trgovska gora (croatia) – in german].– geol. vjesnik, 8–9 (1954–55), 115–121. krainer, k. (1993): lateand postvariscan sediments of the eastern and southern alps.– in: von raumer, j.f. & neubauer, f. (eds.): premesozoic geology in the alps. springer-verlag, berlin–heidelberg, 537–564. 9sremac: equatorial shelf of the palaeozoic supercontinent... marjanac, t. & sremac, j. (2000): middle permian calcispongal cement reef on the velebit mt.– in: pamić, j. & tomljenović, b. (eds.): pancardi 2000. dubrovnik, croatia, 1–3.10.2000. fieldtrip guidebook. vijesti hrv. geol. društva, 37/2, 135–138, zagreb. milanović, m. (1965): salopekiella, novi rod familije dasycladaceae iz permskih sedimenata velebita (salopekiella, a new genus of the dasycladaceae family from the permian sediments of the velebit range).– acta geol., 5, 373–382, zagreb. milanović, m. (1966a): likanella – a new permian genus of the family dasycladaceae (likanella – novi permski rod familije dasycladaceae).– geol. vjesnik, 19 (1965), 9–13. milanović, m. (1966b): goniolinopsis – a new permian genus of the family dasycladaceae (goniolinopsis – novi permski rod familije dasycladaceae).– geol. vjesnik, 19 (1965), 115–121. milanović, m. (1968): salopekiella? kochanskae n.sp. (dasycladaceae) from the permian of the velebit mountain (salopekiella? kochanskae n.sp. (dasycladaceae) iz perma velebita).– geol. vjesnik, 21 (1967), 157–160. milanović, m. (1974): kochanskyella (chlorophyta, dasycladaceae), a new permian genus of the mount velebit, croatia (kochanskyella (chlorophyta, dasycladaceae) iz perma velebita).– geol. vjesnik, 27, 127–132. milanović, m. (1975): salopekiella? breziki n.sp. (calcareous algae, dasycladaceae) from the permian of mt. velebit (croatia) (salopekiella? breziki n.sp. (vapnenačke alge, dasycladaceae) iz perma velebita).– geol. vjesnik, 28, 81–86. milanović, m. (1981): carboniferous microfossil associations from gorski kotar, hrvatsko zagorje and banija.– palaeont. jugosl., 28, 1–34, zagreb. pešić, l., ramovš, a., sremac, j., pantić-prodanović, s., filipović, i., kovacs, s. & pelikan, p. (1988): upper permian deposits of the jadar region and their position within the western palaeotethys.– mem. soc. geol. ital., 34 (1986), 211–219. raffaelli, p. & šćavničar, b. (1968): naslage gornjeg paleozoika like i gorskog kotara [upper palaeozoic deposits of lika and gorski kotar – in croatian].– i. kol. geol. dinar., ljubljana, 21–27. ramovš, a. (1958): razvoj zgornjega perma v loških in polhograjskih hribih [development of the upper permian in the loški and polhograjski hribi – in slovenian].– razprave sazu, 1, 451–622, ljubljana. ramovš, a. (1968): razvoj paleozoika v slovenskem delu zunanjih dinaridov (die entwicklung des paläozoikums im slowenischen teil des aussendinariden) [development of palaeozoic in the slovenian part of the outer dinarides – in slovenian and german].– i. kol. geol. dinaridov, 1, 7–19, ljubljana. ramovš, a. & kochansky-devidé, v. (1981): permian–triassic boundary in brušane village (velebit mt., croatia).– geologija, 24/2, 327–330, ljubljana. ramovš, a. & sremac, j. (1986): permian reefs in yugoslavia.– igcp project no. 5: proceedings. final meeting, sardinia 1986, cagliari, 69–76. ramovš, a., sremac, j. & kulenović, e. (1987): results of biostratigraphical investigations in western yugoslav paleozoic realized in igcp project no. 5.– in: flügel, h.w., sassi, f.p. & grecula, p. (eds.): pre-variscan and variscan events in the alpine–mediterranean mountain belts. alfa publ., 397–406, bratislava. ramovš, a., hinterlechner-ravnik, a., kalenić, m., karamata, s., kochansky-devidé, v., mirković, m., petkovski, p., sremac, j., krstić, b., kulenović, e. & temkova, v. (1990): stratigraphic correlation forms of the yugoslav paleozoic.– rend. soc. geol. ital., 12 (1989), 359–383. ross, c.a. & ross, j.r.p. (1995a): foraminiferal zonation of late paleozoic depositional sequences.– marine micropal., 26, 469–478. ross, c.a. & ross, j.r.p. (1995b): permian sequence stratigraphy.– in: scholle, p.a., peryt, t.m. & ulmer-scholle, d.s. (eds.): the permian of northern pangea. vol. 1. paleogeography, paleoclimates, stratigraphy. springer-verlag, berlin–heidelberg, 98–123. rukavina, d. (1973): prilog poznavanju gornjopaleozojskih školjkaša like i sjeveroistočnog podnožja velebita (a contribution to the knowledge on the upper paleozoic bivalves of lika and the northeast foot of velebit mt. (central croatia)).– geol. vjesnik, 26, 319–323. salopek, m. (1942): o gornjem paleozoiku velebita u okolici brušana i baških oštarija [on the upper palaeozoic of the velebit mt. in the vicinity of brušane and baške oštarije – in croatian].– rad jugosl. akad. znan. umjetn., 274, 218–272, zagreb. salopek, m. (1948): o gornjem paleozoiku sjeveroistočnog podnožja velebita i like [on the upper palaeozoic of the northeastern slope of the velebit mt. and lika region – in croatian].– prir. istraž. jugosl. akad. znan. umjetn., 24, 1–75, zagreb. salopek, m. (1952): o gornjem permu velike paklenice u velebitu [on the upper permian of velika paklenica in the velebit mt. – in croatian].– rad jugosl. akad. znan. umjetn., 289, 5–26, zagreb. salopek, m. (1960): o gornjem paleozoiku u okolini mrzle vodice i crnoga luga u gorskom kotaru [on the upper palaeozoic in the vicinity of mrzle vodice and crni lug in gorski kotar – in croatian].– acta geol., 2, 121–132, zagreb. salopek, m. (1961): geološki odnosi paleozojskog prodora okoline smrečja, tršća i čabra u gorskom kotaru [geologic settings of the palaeozoic tectonic belt in the vicinity of smrečje, tršće and čabar in gorski kotar – in croatian].– acta geol., 3, 243–249, zagreb. savić, d. & dozet, d. (1985): osnovna geološka karta sfrj 1:100000. tumač za list delnice l33–90 (basic geological map of sfrj 1:100000. geology of sheet delnice).– geol. zav. zagreb & geol. zav. ljubljana (1983), sav. geol. zav., beograd, 66 p. scotese, c.r. (2002): plate tectonic maps and continental drift animations.– paleomap project – www.scotese.com. scotese, c.r. & langford, r.p. (1995): pangea and the paleogeography of the permian.– in: scholle, p.a., peryt, t.m. & ulmer-scholle, d.s. (eds.): 10 geologia croatica 58/1 the permian of northern pangea. vol. 1. paleogeography, paleoclimates, stratigraphy. springer-verlag, berlin–heidelberg, 3–19. skaberne, d. & ogorelec, b. (2003): žažar formation, upper permian marine transgression over the val gardena formation (javorjev dol, sw from cerkno, western slovenia).– in: vlahović, i. & tišljar, j. (eds.): 22nd ias meeting of sedimentology – opatija 2003, field trip guidebook, 59–61, zagreb. sokač, b. (1973): geologija velebita [geology of the velebit mt. – in croatian].– unpubl. phd thesis, university of zagreb, 151 p. sokač, b., šćavničar, b. & velić, i. (1976): osnovna geološka karta sfrj 1:100000. tumač za list gospić k33–127 (basic geological map of sfrj 1:100000. geology of sheet gospić).– inst. geol. istraž. zagreb (1967), sav. geol. zav., beograd, 64 p. sremac, j. (1986): middle permian brachiopods from the velebit mt. (croatia, yugoslavia) (srednjopermski brahiopodi velebita (hrvatska, jugoslavija)).– palaeont. jugosl., 35, 1–43, zagreb. sremac, j. (1991): zona neoschwagerina craticulifera u srednjem velebitu [neoschwagerina craticulifera zone in the middle velebit mt. (croatia, yugoslavia) – in croatian].– geologija, 34, 7–55, ljubljana. sremac, j. (2001): ekvatorijalni šelf permskog superkontinenta – kolijevka jadranske karbonatne platforme/platformi [equatorial shelf of the permian supercontinent – craddle of the adriatic carbonate platform/platforms – in croatian].– in: dragičević, i. & velić, i. (eds.): 1. znanstv. skup “karbonatna platforma ili karbonatne platforme dinarida”, zagreb 1–2. 10. 2001. knjiga sažetaka, 9–16, zagreb. sremac, j. & aljinović, d. (1997): upper palaeozoic fossils from clastic sedimentary rocks in the gorski kotar region.– geol. croat., 50/2, 187–199. sremac, j. & kochansky-devidé, v. (1982): paleozoik hrvatske (kratki pregled) [paleozoic of croatia – a plate 1 carbonate producers in the carboniferous and the lower permian of croatia 1 foraminifera priscella prisca (rauzer-cernousova). lower carboniferous (viséan); from younger clastic sediments. bizek, medvednica mt. – 100x. 2 calcareous algae gyroporella likana kochansky-devidé. upper carboniferous (moscovian). brnjičevo, velebit mt. – 30x. 3 foraminifera bradyina cribrostomata rauzer-cernousova. upper carboniferous (moscovian); from younger clastic sediments. bizek, medvednica mt. – 100x. 4 algosponge claracrusta calamistriata vachard & montenat; foraminifera cribrogenerina sumatrana (volz); lower permian?; from younger clastic sediments. bizek, medvednica mt. – 25x. 5 foraminifera pseudoschwagerina cf. moelleri (rauzer-cernousova). lower permian (rattendorf group). popov panj, velebit mt. – 10x. 11sremac plate 1 .' j 10":'-"' y. , 12 geologia croatica 58/1 short review – in croatian].– in: sremac, j. (ed.): vodič ekskurzije. terenski sastanak velebit (1982). igcp project br. 5, jugosl. radna grupa, 3–7 (41–42), zagreb. sremac, j. & mihajlović-pavlović, m. (1981): graptolites of mt. medvednica (zagrebačka gora).– rad jugosl. akad. znan. umjetn., 404, 65–68, zagreb. stampfli, g.m., borel, g., cavazza, w., mosar, j. & ziegler, p.a. (eds.) (2001): the paleotectonic atlas of the peritethyan domain.– cd-rom, european geophysical society. šćavničar, b. & šušnjara, a. (1967): geološka i petrografska istraživanja trijaskih naslaga u gorskom kotaru (područje lokve–gerovo) [geologic and petrographic investigations of the triassic sediments in gorski kotar (lokve–gerovo area) – in croatian].– geol. vjesnik, 20, 87–106. šikić, k. (1995): prikaz geološke građe medvednice [geology of mt. medvednica – in croatian].– in: šikić, k. (ed.): geološki vodič medvednice. institut za geološka istraživanja & ina d.d. – naftaplin, 7–40, zagreb. šušnjara, a., sakač, k., jelen, b. & gabrić, a. (1992): upper permian evaporites and associated rocks of dalmatia and borderline area of lika and bosnia.– geol. croat., 45, 95–115. tišljar, j. (1992): origin and depositional environments of the evaporite and carbonate complex (upper permian) from the central part of the dinarides (southern croatia and western bosnia).– geol. croat., 45, 115–127. tišljar, j., vlahović, i., sremac, j., velić, i., veseli, v. & stanković, d. (1991): excursion a – velebit mt. permian–jurassic.– in: vlahović, i. & velić, i. (eds.): excursion guide-book, sec. int. symp. adriatic carbonate platform, zadar, croatia, yugoslavia, may 12–18, 1991, 3–49, zagreb. velić, i., vlahović, i. & matičec, d. (2002): depositional sequences and palaeogeography of the adriatic carbonate platform.– mem. soc. geol. it., 57, 141–151. wignall, p.b. & twitchett, r.j. (2002): extent and duration of the permian/triassic superanoxic event.– in: koeberl, c. & macleod, k.g. (eds.): catastrophic event and mass extinctions. impact and beyond. geol. soc. am., spec. paper, 395–413. ziegler, a.m., eshel, g., mcallister rees, p., rothfus, t.a., rowley, d.b. & sunderlin, d. (2003): tracing the tropics across land and sea: permian to present.– lethaia, 36, 227–254. manuscript received march 30, 2004. revised manuscript accepted january 19, 2005. plate 2 carbonate producers in the middle permian of croatia 1 calcareous algae mizzia velebitana schubert and permocalculus tenellus (pia), microproblematica tubiphytes obscurus maslov and gastropods. middle permian. milašnovac, velebit mt. – 25x. 2 calcareous algae mizzia velebitana schubert and m. cornuta kochansky & herak, foraminifera dunbarula nana kochansky & ramovš and palaeotextulariidae, brachiopoda, radiolae. middle permian. crne grede, velebit mt. – 25x. 3 cortoid grainstone with fragments of calcareous algae and foraminifera. middle permian, road gospić–karlobag, velebit mt. – 25x. 13sremac plate 2 14 geologia croatica 58/1 plate 3 reef building biota in the middle permian of croatia 1 framestone with calcisponges: inozoa gen.div. and sinocoelia lepida zhang & fan. acetate peel – negative. road gospić–karlobag, velebit mt. – 4x. 2 floatstone (tempestite) with unsorted reef particles – calcisponges, bryozoans, foraminifera, calcareous algae. acetate peel – negative. road gospić–karlobag, velebit mt. – 4x. 15sremac plate 3 16 geologia croatica 58/1 plate 4 middle permian sediments from the basinal slopes 1 graded bioclastic wackestone–packstone with foraminifera (neoschwagerina) and calcareous algae. acetate peel – negative. kalvarija, velebit mt. – 3x. 2 mudstone with bioturbations. acetate peel – negative. kalvarija, velebit mt. – 2x. carbonate producers in the upper permian of croatia 3 calcareous alga atractyliopsis lastensis accordi. bregana – 25x. 4 earlandiaceae. brušane – baške oštarije, velebit mt. – 50x. 17sremac plate 4 18 geologia croatica 58/1 plate 5 low diversity fossil communities of the lower triassic 1 dolomite with stromatolites. lower triassic?, brušane, velebit mt. 2 micaceous sandstone with claraia clarai (emmerich). scythian, gorski kotar. 3 marly dolomite with turbo rectecostatus hauer. scythian, muć. 19sremac plate 5 20 geologia croatica 58/1 i geol. croat . i 50/1 i 33 48 i j 9 figs. i i zagreb 1997 the development of the eocene platform carbonates from wells in the middle adriatic off-shore area, croatia vlasta tar! kovacic key woi-ds: eocene, platform carbonates, wirelinc logs, adriatic o it-shore, croatia. abstract [n the middle adriatic deep off-shore wells th e following sedi­ mentary f:lci cs ex isl: fenestral :h1d charophyte limestone facies (x): facies of foraminiferal wackestone-packstone. ostracod marls and fine grained breccia cong lomerate (a): facies of foraminiferal packstonc­ grai nstone (b) and milio lidal mudstone-wackestone (c): fac ies of porous limestone?, grai nstone? (v): facies of fossi liferous mudstone­ p;lckstonc (d); alga l botlnd stonc/bindstonc and wackestone fac ies (e): facies o f the foraminiferal mudstone-packstone (f); nli/nll/iliites­ di.h·ot:ydillu flo;ttstone-pacbtone and g rainstone-r ud stone faci es (g). the sedi ment s were deposited close to the carbonat e platform marg in. beds of facies x hav e an uncertain str<ltigrap hi c position; you nge r than the cre\<leeous but older than the cu i sian. a transgres­ sive sequence ihal is composed of facies a, b, c and y was formed during the cuisian, where~\<; the others belong to lutct ian (and diar­ ritzian). at the end of the middl e eocene lhey were tectonically com­ pressed and cove red by fl ysch deposits. good stratigraphic correla­ tion between the wel ls along the dinaric slfike strongly suggests lhat the facics are latcrally cxtens ivc in th is direction. perpendicul ar to the trend they arc considerably reduced . oil shows in the kalci well orig inated from the lower cretaceous so urce roc ks (evaporite com­ plex). 1. introduction the eocene platform carbonates, alt hough of rela­ tive ly limited extent in ihe adriatic off-shore, bccame an interesting explora tion projcct when some oil shows in the wells jadran-3, jadran-9 and kalel were discov­ ered. this work is a study of the sedimentary platform cad es development ancl the cessation of platform condi­ tions during the lower (cu isian) and midd le eocene (lutetian to biarritizian). in the north and middle adri­ atic, the eocene platform carbonates were drilled only in the wells katei, jadran-3, kornati more-4, jadran-9 and susak morei. fi g ure 1 shows the well locations together with the north-eastern part o f the tertiary (dugi olok) depress ion and the south-eastern part 01" the islrian plat form. ina induslrija \lane. exploration and devejop merll, subiccva 29, j ir-1oooo zagreb, croatia. 2. methodology the interpretation 01" the eocene carbonate platform facies is based on analysis of the wircline log facies compared with the geological information acquired dur­ ing drilling and by th e transformation of the physical charac teristics of the sedim ents (w ire line log facies) into geological entit ies (sedimentary fac ies). thi s met hod was scientiricall y developed by selley rrom 1970 to 1985 and since then it has been widely used in the oil industry. espec ially as the bas is ror building facies models and reconstructions of sedimentary envi­ ronments. the wireline log faci es interpretation was carried out on the logs which primaril y reliect the lithological characteris tics of the obscrved sedimcnts, i.e. the natur­ a l radioactivity (gamma rays and spcetralog) and poros­ ity logs (neutron, density and acoustic logs). the tec hnique is primarily qualitative and re lics heavily on the visual identification or the coherent units. the cri teria used for separat ing the units depend s on the geological data acquired by drilling. there is no stan­ dard procedure for separating certai n wi rel ine log facies, although it wou ld be logical to separate the obvi­ o us cohercnt rocks first, and then in corre lation with neighbouring we ll s, g radually perform more dc tai led scp:.uution. the sedimentary fac ies interpretation is based on the detailed study of the cored intervals and sed imentologi­ ca l core descriptions according to the micro-a nalyses (lithoand biostratigraphic data). for the cored inte rvals the ir constituent sedimentary faci es we re de tennined and added to the app ropriate wirel ine log facies. for the wi reline log fac ies which were not co red, sedimentary racics were det e rmined from mud cuttings and by comparison with s imilar wire line log facies that were cored in the same or in the neighbouring well s. 3. eocene carbonate facies in the kate-i, jadran-3, korna ti more-4, jadran-9 and susak more-i wells the eocene platform carbonates in the examined wells are subdivided into ten wire line log facies of con­ s islent intervals (x, a, b, c, y, d , e, f, g and i-i). for • ,l each of the wireline log facies the geological infonna­ tion acquired by drilling, deteml ined the corresponding sedimentary facies. 3.1. facies x sedimentary facies of fenestral and charophyte limestone (salt and brackish marshes, tidal nat) this is the oldest palaeogene facies deposited on the karst plane formed of different units of the upper cre­ taceous (cenomanian to maastrichtian), after emersion and eros ion during the palaeocene. h is :lcarly shown on the wireline log diagrams by the high values of com­ pensated density log (from now on referred to as densi­ ty) 2.45 2.70 glcm', by the low values of compensated neutron log ( from now on referred to as porosity) 4j 0%, by low values of borehole compcnsated acoustic log (in further text acoustic) approx. 230·\0'(' slm (70 mcs/f!) and by low radioactivity (in further text gamma ray intensity) 10-20 api. the thickncss va ries laterally from 7-17 m. mud loggi ng iden tified the following lithologies: bauxitic ooids of tangential concentric construction and pe liti c c lay with abundant pyrite in kornati more-4 (fig. 2), fenestral and charophyte limestone with vugs fill ed with mosaic drusy calcite in katei (fig. 3), pyritic fenestral limestone in jadran-9 (fig. 4) and fen­ estral limestonc with desiccation cracks, ostracods and miliolids in jadran-3 (fig. 5). these sediments were deposited on a low energy tidal flat or salt and brackish marshes under anoxic con­ ditions. the proximity of the coast wi th beaches is typi­ fi ed by dcposits in the area of the kornati morca well. due to the lack of index fossils, it is imposs ibl e to determine the age of these sediments. 11 is certain that they represent a shon transgressive sequcncc beforc the middle cu isian (the approximate age of sed iments from the ncxt tran sgress ive cycle). if the transgression was caused by eustatic sea level rise, it could be the result of maximal flooding by the end of the lierdian ( haq et ai., 1987). the subscq ucnt emcrsion until the next transgression was rela ti vely short, 1-2 million years. o , geologia cromie:! 50/1 50km fig. i location map. 3.2. facies a sedimentary facies of foraminiferal wackestone-packstone, marl with ostracods and fine-grained breccia conglomerate (coastal environment with repeated shajlowing and emersions) thc main wireline log characteristic of thi s facies is the very high gamma ray intensi ty. the gamma radia­ tion curve has the typical express ion easi ly spolled on all exam ined wells ("hot streak" marker), thc gamma ray intensity is highest at the lower part of the interval, from 70 api in the kate-l well lip to 220 api in the susak more-i well (figs. 3 and 6). in the upper part of the interval the valucs arc considerably lower, up to 50 api. spectra log analysis from katei proved that the uremi c component has more influe nce than either the thorium or potassium radioactive group. thc coal from the lower eocene mines in rasa, 1st ria , also has an ura­ nium content up to 300 ppm (fertl, 1979). this ura­ niulll enrichmelll should bc of the samc origin because the sediments arc of the samc agc and from closely related environments. according to the lit erature (fertl, 1979) a high uranium level in carbonate sedi­ ments can indicate the presence of organic or phosphate rich deposits or permeable zones through which thcre is a circu lat ion of underground waters enriched in urani­ um salts. the density, porosity and acoustics values arc almost identical to the previous facies, except for the first few met res (fig. 7). 'rhc hi gher porosity va lue, gamma ray intens ity , highe r speed or acoust ic wave sprcading and densi ty depend on the presence of clay and breccia-conglomerate in the argillaceous matrix. facies a was studied in cores from the well s jad­ ran-3 (figs. 5 and ii) from 1764-1766 m, and jadran-9 (fig. 4) from 1324-1327.3 m. the lowest 10 e l11 of the core in jadran-3 is a fine grained limcstone breccia con­ glomerate wit h weakly rounded clasts in a matrix of skeletal detritus. these are followed by o rganic rich limesto ne, ostracods marl with burrows, desiccation cracks and fenestral milolid-coskinolinid limestone. the lithofacies of foraminiferal wackestone-packstone limestone prevails. fractures and intcrgranular porosity tari kovac:i~: the developmenl of ihe eocenc platform carbonatcs from wells., kornati more 4 20api gr rt-..j.... --~­ >~ ac ~ 90msec/ft o ~ 120 ~ ~. \ ' / i , e / ~ \ ~ o i? o ~ lithology \ 8. f----7. i-8. 7. i-z .. >w >6. ~ i-5. 3. 1. z .. !!i " u o· o q. legend: nummutitids alveotinids v=::j discocyclinids c::=:') miliolids l1 conical foraminifers &benthic foraminifers (y planktonic torams j algae @ corals p bryozoans 35 echmids ~'-...l? shells' debris rudis-ts charophyta microcodium ostracods dessication cracks caliche birds eyes ooids i "-.;'110 i 1 '--hi fig. 2 scqucncc of palaeogene carbonates in the deep well komali morc-4. legend: i) facies of fenestra! and charopfjy/rl limestone (x); salt and brackish marshes, tidal /lat cnvironment; 2) facies of foraminiferal wackestone-packstone, marl with ostracods and fille grainecl breccia conglomeratc (a): coastal environme nt with repeated shal lowing and emersions: 3) facies of foraminiferal packstone-grainstone limestone and miliolidal mudstone-wackestone limestone (8 and c); coastal env ironment with repeated shallowing and emersioils: 4) facies of porous limestone ?grainstonc (y); ?beaches: 5) facies of fossi liferous mudstone-packstone limestone (d); shallow platform and mud mounds envi­ ronment; 6) facies of algal boundstone (bindslonc) and wackestone (e); platform margin buildups; 7) facies of the foraminiferal l1ludstone­ packstone (f): foreslopc environment: 8) facies of nlllillilii!ites-discocyciina floatstone-packstonc and grainstone-rudstone (0); foreslope environmcnt: 9) shallow marinc mudstone-wackestone; [0) shallow marine packstone-grainstone; ii) core samples: 12) mud samples. arc filled with bitumen. the sed iments were deposited in a pericoastal environment with repeated shallowing and emersions. ]n the jadran-9 well core mierocodium and pisolitic wackestone-packstone alternate with some bauxite and fossiliferous packstone-wackestone with shell debris, bryozoans, red and green algae and benthic forami ­ nifers in argillaceous mudstone and caliche. microcod i­ lim is developed by mycorrhizal calcification (symbio­ sis of fungi and cortical cel ls of the plant roots) and caliche typical of [hc limestonc pajacosoil (klappa, 1978) , so they often occur together in the sed iment. 16 e g o n o 1\l n kate 1 15 gr ~ f--..,j. ---....i... ac 75 mcs/ft sp 1'~ .: ~ -f -? ~ ~g -~ , ~ ~, .-, > , f ~ < ,---' ~ f:2m \. ~ ~ , > ~g -, , 1 , , , i ; , e , i , , . i , , ~? j ':. , { , <' , '-" 0 v> '" lithology ~ .. ~ .. v> -i :;i 1 i lev @ :1! -jp f-p 'j.. i .1'&',., !z ! ;; '" " z '" .. isl. 8. 7. iz 7. .. -& n i8. _. a: a: i.. '" 6 . , z i.. iw i5. " ~ 3.z .. iiii 2 . b 1 g w ~ 3 . :. 5 . z " ;: z !.! a: l­ v> .. " '" fig. 3 sequence of pa laeogene carbonates in the deep we ll katei. for legend sec fig. 2. such facies indicates :1 coastal environme nt with varia­ lion s of the sea leve l over a low lying plain. coas tal (supratidal) sed iments alternate wi th sed iments indica­ t ive o f highly reduc tive s wamps thai are seasonal ly jadran -9 gr :i: iae .. .. 0 0 i 0 0 '" geologia c ro:l1ica 50/1 iz '" ~ lithology ~ a: ;; z w 7. 8 . 5 . 3. 2 . " .. iw l" ~ z .. '" " u ~ z o z w v> fig. 4 sequence of palaeogene carbonates in the deep well jad .. "n-9 . for legend sec fig. 2. dried and occasionally with marine mitotid limestone due 10 minor sea level rise (davis, 1985). geochemical studies of the core samples determined that anlorphous huminil c/vi trinite kerogen (>95 % ) is the dominant form of organic matte r (corg 0.260.43 % ), and it is therefore assumed that it was de ve­ loped by the biodegradation or a te rres tria l p recursor. the deposits do not exhibi t the source rock characteris­ tics as the major part of the organi c mallcr has bee n oxidiscd (high hi) within the sed imentary environme nt. the maturation parameter t u13x (407 -41 o°c ) indicates an especia lly low degree of thermal transformation, and the re fore these sed ime nts cannot be cons idered as the source rocks. mud samples in ot her intervals or kornali morc-4 , katei and jadran-9 wells (figs. 2, 3 and 4) havc s imi­ lar charac te ri s tics to thc rocks in the cored in tc rvals . the thickness of th is facies varies between 10-26111. t;hi kovacic: the development orlhe eocene plalfonn carbon~ tes from well s ... ~ >­.. w o o o ~ o o ., jadran 3 10 api gr 60 u) -------------~--w ac 9?mcs/ m 50 ~ .. "' '" '" lithology :. w ,. z i1 ;; z w 6 . 5. w (!) « >­ w >­ ::> ~ z 3 . '" <f> 2 . 1. pc? z '" z o z w <f> fig. 5 sequence of palaeogcne carbonates in the deep well jadran-3. for legend see r ig. 2. sed imentary faeies 10 which the sediments of the wirel ine log facies a belong to, are sediments of coastal plain wi th fresh water flow s, swamps that occasionally dry ou t, and the beaches that are flooded by the sha llow sea that fo rms shallow res tricted lagoons. due to the lack of index fo ssils the age is roughly de term inat ed as lower and /or middl e cuis ian on the basis o f caskinolina sp. , fallate//a sp. , spirolina sp. , discorb ids, rol alid s, sma ll miliolids , ostracod s and green algae, and because the sediments o f facies a are confo rmably overlain by younger sediments of a deter­ minable age without any sedimentation break. 3.3. facies band c sedimentary facies of foraminifera l packstone-grainstone (facies b) and miliolid mudstone-wackestone (facies c) (the t idal flat environment) this fac ies is composed by alternation of facies b and c in a ll the we ll s. the density , po ros ity and acoust ic logs show th e good correlation of the two facies in a ll wells except in the katel well (figs. 3 and i ~ >­.. w o o ~ susak more 1 g r 20api 120 (i) .j. ___ _ __ ....1. w 100 .ac m$c/it ~ 5( ~ '" <f> lithology t i reverse f lt >­z ! ~ w <f> ~ '" o ~ <f> i-4. 3. i-2. 37 w z w g ::; o , w z w @ z '" iii '5 () o· 1. ~ .. <f> "' 4 . 3. i-2 . 1 . .. <f> "' z '" z ! w () z '" <f> :; () () fig. 6 seq ucnce of pal aeogene carbonat cs in the decp well susak more-i . for legc nd sec fi g. 2. 8) where the exchanges are more frequent in relation to the thickness of both faci es. porosity in faci es b varies from 1010 25%, density 2. 35-2.60 g/cm3 and acoustics 38 geologi:l croalica 50/1 2 facies "a" ~\o'!. 2.2 iadran -l( o) co, c., (1174-11s!hn) xatb.i ( 0) (237s-2j"m) 25 ~ 2.4 ~ ~ ~c()~' ~ 2.6 c~~ .. ~ '" 2.8 3 -5 o 5 10 15 20 25 co:mpensated neutron porosity (%) 100 0 0 0 f~cies '''a'' 0 90 80 0 jadran-j ( 0 ) 0 (17s9-1774m) 0 0 kate-i co) (2375-238sm) ~ • gg .. ;: 0 ·e~o~ ! o 0 , ~; 20 o'v ", 0 10 o so 60 70 80 90 100 110 120 acoustic (~s i it) from 197-230.10.6 slm (60-70 mes/ fl ). the values of these parameters in the susak morc-l well (fig. 6) arc not re liable because of the cavernous borehole, but the charac te ristics of the band c faci es a rc still visible. the gamma ray curve cloes nol reflect the changes in these facie s in any of the wells. in the lower part of the interval the va lues arc hi gher between 30 and 70 api. in lhe upper parl , lhey do nol exceed 30 a pi unils. only in the susak more 1 well the va lues arc very hi gh , among 50 and 100 api unils. the facies was cored only in the jadran-9 well, but in the tectonicaly rcpcated section in the interval 13421345.2 m. bauxitc oolites point to emcrs ion and/or the vic inity of karstificd coast, while fo ssilifc rous wacke­ stone-packstonc and grainstone limestone with benthic foramin ifers and eeilinids, algae and shell debris indi30 130 140 a b foi g.7 facies a: a) cross pl ot response showi ng car­ bonate point di stribution; b) gr/ac cross plol response. ca te high energy shallow water environment. facics c was cored in lhe inlerval 10291032 m. li ghl brown miliolid wackcslone-packs lone alte rnates with dark grcy and brown fe nes tral wackestone with gastropods. fencstrae arc fill ed wit h internal sed im ent and mosaic drusy ca lcite cement. shallow karstified surfaces and geopctal fabr ics we re al so noted. t he environm en tal energy was low. the mud samples of the samc facies in the ka tc-i well also contain ostracods and oncoids. bolh raeies arc lypieal for lhe lidal flal , lheir appear­ ance and development can be connected to thc a ltcrna­ ti on of the sed iments depositcd in tidal channels (facies b) wilh lhose from lh e shellered lagoons (ponds) of hi gher salinity (facies c). the regularity of the alterna­ tion or both fac ies in all the we ll s (exccpt thc katc-l well ) is curious. it is impossible to determinc whether t"ri kov;ti;ic: the development of the eocene pi::l!fonn carbonatcs from wells ... 39 2 ,--------------, 2.2 'a ~ 2.4 ~,,~ 2.6 ~ 2.8 facies "b" jadran 3 (.) (1730-1759m) kornall more _ 4 (.) (i690-1710ld) 3 ,-__ . -5 o 5 10 15 20 25 compensated nelitron porosity (%) 00 90 facies "b" 80 jadran-3 ( 0 ) (17s9-1774m) a 30 b 1kornatimore-4 <.) f-(237s-238sm) 60 . ":.. '. -'. 30 \i~~~ 20 -" ... 10 0 40 '0 60 70 80 90 100 110 120 acoustic (~s 1ft) they represen t shallowing upward cycles or sto rm tide deposits. onl y in the the katei well are facies band c also recognised be low facies x (pi gs. 3 and 17). according to lucie ( 1993) this prese nt s the only known palaeocene tidal nat deposit in the adriatic off-shore. the forami niferal association with coskillolillo per­ pera hottinger & drobne ancl cilry.wlidil/a liiakarskac (van soest), determined the age as lower eocene (middle upper cuisian). 3.4. facies y sedimentary facies of porous limestone '!grainstone (? beaches) facies y was iso latcd only in the susak morel well (fig. 6), on ly on the gamma ray and acollstic logs, because during the drilling at the depth of 775 m (in the 1130 140 fig. r facics 13 : a) cross pt ol response showi ng car­ bonale poinl dislri bulion; b) gr/ac c ross pial responsc. lop of this facies), the com plete loss of mud occurred , and due to cavernous borehole the porosity and density values are invalid . as the well samples were not available the determi­ nat ion or the facies charac teristics and the sed imentary envi ronment was not possible. although, [he physical characteristics of scdimcnts enable certain assumptions. the decrease of gamma radiation is visible as well as the increase in acoustic value in relation to the facies b in the base. such charac teristi cs corespond to the po rolls limestone (?grainstone) developed in the hi gh energy envjronmcnt , where the mud component was washed out. if that is the case, following the walter 's low (wilson , 1975) on the lateral and vcrtical changes of the facies, these deposits could be interpret­ ed as the beach sands deposited over the tidal fla t facies 40 geologia cromie:! 50/1 2 facies "d" s\.0 1> 2.2 jadran -3(o) (1604-1 67sm) kate· i (0) (221s-2299m) '8 2.4 ~ ~ ~ ~c\)), ~ 2.6 c~;!>." " s "' 2.8 3 l-____________________ ~~~~ ~ 0 5 10 15 w ~ ~ a compensated neumon porosity (%) 80 facies "0" jadran 3 ( 0) (1604-167sm) kate-! co) (221s-2299m) kornatimore-4 c, ) (is7s-163sm) ,,~::, 'f 0 '0 60 70 80 90 100 110 acoustic (~s i ft) 13 and c presenting regrcsive part of the sequence. 3.5. facies d sed imentary facies of fossiliferous mudstone packstone limestone (the shallow phltform and mud mounds environment) 120 in the north-western part of the carbonate platform the sedimentary sequence ends wit h the emersion by the end or the lower eocene (facies y in the s usak morci well). in the other areas the sedimentat ion con­ tinues during the gradual sea level ri sco f-ac ies d fol ­ lows con formably on the facies b in the kolllati more4, katei, jad ran -9 and jadran-3 wells (figs . 2, 3, 4, 5 and 9). the lower part of (he interval is composed of sedi ­ ment s with porosity vary ing between 3-18%, density of 2.50-2.65 g/em and aco list ics bct ween 197-230· 10.6 s/m (60 and 70 mes/h ). [n the upper part of the inte rv a l, 130 b fig. 9 facics d: a) cross pl ot response showi ng car14{) bonate poi nt di stri blltion: b) gr/ac c ross plo l responsc. which has been developed in a ll the wells except the jadran-9 well , the sediments are of hi ghe r dens ity (2.60-2.70 g/cm), lower porosity ( 1-8%) and aeo list ics ( 184197.10-6 s/m, i.e. 56-60 mes/ft ). gamma ray inten­ si ty is low: 10-20 api. in the jadran-9 well the thi ck­ ness of these sediments is 8-22 m, whi ie e lsewhere is 58-80 m. the fac ies has not bee n cored. accord ing to the anal ys is of mud samples, m udsto ne, wackestone and packstone containing miliolicls, conica l and large foraminifers and shells and corals debris, were deposi­ ted in the subtidal zone beneath the normal wawe base on the shallow platform. the fra gments of coral s and she ll s probably originate from di stant shoals (facies e) or from the mud mounds. tn the upper part of the facies d of the jadran-3 well (fig. 5), mostly in the mudstone and wackestone/ooat'i\l ri kov;lcic: '111e developmelll of the eocene pi:lifonn c:hbona l c.~ from wells ... 100 90 facies "e" 80 kate-i (.) (2168-221sm) kornatimore 4 (.) ( isis-1s7sm) 30 20 -~-.~ p' , ,. .. ~ . • ' \0 o 2.8 2.6 2.4 2.2 density (glcm') stone, new faunal clcments appear: corals and plankto­ nic foraminifera. t hese sedim ents can be compared with the illud hu mmocky cross lami nation in the rcef base (elloy , 1982) where they arc actually located. it is important that the foraminiferal community changes in this faci cs . numjllulites sp., opercu/il/(f sp., a ssilina sp., and discocyc!illa sp. of ihe midd le eocene (lut etian) age appcar for thc first lim c. the boundary between thc cui s ian and lu tclian coincides wit h the change of facies band c into facies d. 3.6. facies e sedimentary facies of algal boundstone (bindstone) and wackestone (marginal platform buildups) the sedim ents of thi s facies arc developed in the komati more-4, katei and jadran-3 wells (figs. 2, 3, 5 and 10). on the wi reli nc logs the typical scrrated curvc shows acoustics 56-90 mcs/ft , po rosity 3-30 % and dens ity 2. 35-2.70 g/cm3 . the gamm a ray value is less than 10 api. 'fh e faci es in jadran-3 well was tcs ted by the mech­ anical core in the interval 1565-1565.3 m (pi g. 12). fi£. i i ostracode mtt d)o,tone-wackes tone. facies a. earl y eocene (cuisian). jadran -3. 1764 m, 25x. 41 --2 fig. 10 facies e: gr/den cro ss plot response. the rock is classified as al ga l bound stone (bind ­ stone) and wackestone according to the classification of embry & klova n ( 1971 ). it con tain s large foramini fera (nuljiljililites, discocyclill(l , amphistegina and operculina), fin e benthic foraminifers, planktoni c foraminifers , bryozoans , corals, she ll s, echinids and encrusting red algae. as only a small interval of the fac ies was tes ted by coring (30 cm), it is diffi cult to determine is that the truc rcc f o r some o ther k ind o f margi nal platform bui ldup. according to the reg ional position and the appearance on the se ismi c lines, and also to the vertical and lateral spreading of the consid­ ered faci es, it may be det ermined as the marg inal plat­ form buildup. the changeable porosity is typical for reefs and also for peri -reefal facies. the literature describes in detail the complex processes that des troy primary and/or [0 1111 the secondary poros ity (laporte, 1974; bab ic & zupanic, 1979; toom ey, 1981; elloy , 1982; selley, 1985). in komati morea accordin g 10 the illud cuttings the sedime nt s are dolomitized (a lso expressed all the dens ity and porosity logs) . in the katei we ll , the karst development and open active fig. 12 n/lii/ii/ilii{l 's-lilllo{lwl/lllilllll bindstonefloatstonc, facies e, m iddle eocene (lute ti an). jadrnn-3, 1565 m . 28x. 42 00 90 i 80 facies "f" katet (0) (2070-2168m) kornatimore-4 <.) (1470-1515m) 60 30 20 +-~-0 40 so 60 70 80 90 100 110 120 acoustic (~s/ft) fracture systems are visible on the photo-electrical absorption curve (pef). the rise or the curve value pef from 5 (limestone) to 7-9 in a rew intervals was caused by baroid drilling mud infiltration. in the jadran-3 well this facies is the final member of the carbonate succession. the sedi mentat ion contin­ ues with siliciclastic turbidites, in the deeper sedimenta­ ryenvironment. 3.7. facies f sedimentary facies of the foramini­ feral mudstone-packstone (foresiope environment) facies f overlies on the reefal limestone in the kor­ nati more-4 and kate-l wells (figs. 2, 3 and 13). it appears in the jadran-9 well (fig. 4) between the two intervals of the facies g, while in the kale-j well (fig. 3) it alternates with facies g. the wire-l ine log facies almost looks like facies d. porosi ty varies between 16%, density from 2.55-2.70 g/cm3 and acoustics appro­ ximately 60 mcs/ft. the value of gamma ray intensity doesn 't excecd 15 api units. fig. 14 di.h:ocydina grainstone-packstone, facies f, middle eocene (lutetian), jadran-9, 1445 ill, 25x. geologia croatica 50/ 1 130 140 fig. 13 facies f: gr/ac cross plot response. this facies hasn't been cored. according to the mud samples (fig. 14) there are foraminiferal mudstone, wackestone-floatstone and packstone with coralli­ nacean and bryozoan debris. its thickness is 46-98 meters. sediments from this facies are of lutetian age (spilaerogypsil/a globula (reus), aslerigeril/a rolula kaufmann, diseoeyclil/a sella d' archiac, lepi­ docyclina sp., nummulites sp., turborotalia cerroasu­ lei/sis possagl/oensis (toumarkine & bolli), globigerina sc/1i1i (beckmann». they developed on the very edge of the platform toward the slope and basin, and they are laterally and vertically (waltcr' s law) the first neighbouring member of facies e and g of the transgressive sequence. the main criterion for determining the sedimentary environment was the fossil contenl. bioclastic deposits in which the association of discocyclina, nummulites, asterieyclilla and sphacrogipsina dominate, with the significant presence of planktonic foraminifers, undoubtedly shows the foreslope and toe of slope envifig. [5 nllliilillllites-discocycfina grainstone, facies g, middle eo­ cene (lutctian), jadran-9, 92 [ 111, 28x. tari kovacic: '111e dc"clopmclll of the eocene pl:ltfonn caroon;llcs frolll wells ... ronm en t beneath the wave base (b ignot, 1972; ghose, 1977; drobne et ai., j 991). 3.8. facies g sedimentary faci es of nu mmulites­ discocyclillo floatstone-packstone and grainstone-rudstone (open platform shoals) facies g overlies facies d in the jadran-9 well (fig. 4). in kornati morea and kate-l wel ls (figs. 2 and 3) it slicceeds facies f. in the kornati morei and jadran9 wells it cyclically alternates facies f. the wire-line log characterist ics or fac ies g are poros it y of 3-10% in the kate-i well , up to 25% in kornati mo re-4 we ll and up to 19% in the jad ran-9 well. the density var ies from 2.35-2.55 g/cm3 and acoust ics from 164197· 10 " s/m (50-60 mes/ft) . gam­ ma r3y intensity is approximatc ly 10 api. facies g was studied in mechan ica l cores in kate-! well between 2028-2046 m. according to the lithofa­ cies and sedimentological interpre tation the rock is composcd of ntllili1l11lites-d iscocyclhw noatstone/ packstone wi th occasionally hi gher con ten t of corall i­ naceans and bryozoans and fragments or ech inoderms and shells. the matrix contains fine-grained fossil frag­ ments and carbonatc mud, and rarcly mosa ic drusy cal­ ci te cement. grainstone/rudstone typcs appear very often. primary intraskeletal porosity is hi gh but it was diminished because o f the ceme ntation of intraskeietai cavities. oil shows are connected with frac tures or sty­ lolitic su rface s and tec tonic fabrics wit h variable impregnation of the surrounding rock, especially where there arc dissolution hol es developed. limestone of this fac ies was sed ime nt ed in the open piali'orm shallow water environment. in the ladran ~9 well, the same fac ies was s tudied be tween 915-92 1 m. according to pet rograph ic and lithological ana lyses, the rock is forami nifera l grai n­ stone-packstone (pig. 15) and occasionally glauconitic. because of the high energy environment, there are only a few planktonic foraminifera, whi le large foraminifers (mostly nuii/iiii/lires) are abundant. in the vertical sequence, the sed iments of facies g in ihe wells kale! , kornati more-4 and jadran-9 aggradationally alt ernate with fac ies f o f the forereef environment, like the re fl ection of platform pu lsi ng before its final drowning uncler the s ilic iclastic flysch deposits. sedimen ts of the facies g arc of the lutetian age, and in the katei well they are somewhat younger lutetian to i3iarritzian (operclf/illa biaricensis oppenheim, nii/mlll/lires liii//ecapl/f i30ubee, nlliil­ /lllilires dll}i'ello)'i d' archiac & helm e). 4. ljiscussion 4.1. co .... elation in wells a schemat ic correlation cross secti on (pig. 16) shows the extent of the considered deposi ts along the 43 dinaric st ructural trend, from the susak morel well in the north-west to the kate i well in the sou th ~eas t. they represent the older (carbonate) part of the trans­ gress ive megasequence of the palaeogene and neogene beds. facies x, a, b and c a rc easi ly corrclatable ac ross a ll the we ll s. they were deposi ted in the coastal e nvi­ ronment (facies x and a), and in the tidal nat (facies b and c). in the susak more-l well area, the sedimen tary sequence of th e eocene carbonates was int errupted a t the beginning or the lutetian because of the uplifting of the ca rbonate platform , caus ing the emersion which lasted till the e nd of the upper eocene, when the depo­ si tion of carbonate sediments continues again. the sed i­ me nts of the upper c re taceo us, eocene and lower o ligocene were repeated twice in the well due to a reve rse fault at the depth of approx imately 945 m. the to ta l thi ckness of the eocene sequence in the th rus ted part is 140 m and in the autocht hon 142 m. toward the south and south-cas t the res t of the car­ bonate plat form was oscillating and slow ly drown ing, wit h the te nde ncy of increasing thickness or regarded dcposits. the transgressive sequence continues through the luteti an with fac ies d, e, f and g, and the env iron­ men t changes from int ernal shallow platform toward platform edge. the thicknesses oj" the lutetian depos its in jadran-9 well arc 276, 132 and 157 m (tecton ica lly repeated sequcnces), in the jadran-3 well is 288 111 , in kornati more-4 we ll 369 111 , and in the katei well 395 m. in the jadran-3 well area fac ies e (p latform marg in bu il dup) completes the ca lcareolls part of the transgres­ sive mcgaseq uence, wh ich continues with fly sch sedi­ ment ation. facies g and f in the ladran-9, kornati morea and kate-l wells arc repeated cyclically. shoals or open sha llow waters pass in to sedime nts of the fo re­ reef e nvi ro nme nt. such an a lte rnation of facies is the result o f multiple, rela tive osc illa tions of sea level (pig. 17) that do not correspond wit h the eustat ic c urve of the sea level change (haq e t a i. , 1987) . thi s reflects the pulsing of the platform before its fin a l drowni ng (sciilager , 1981) because of the subsidence in front of the growing thrust structures of the dinaridcs in the east. because of fo ld ing ( recumbent fold ) and thrusting, in the jadran-9 well, the same palaeogene earbonale sediments were drilled in three intervals, with the mid­ dle interval being inverse. in all three inlcrvals the sequence of facies from x to g is identical. the thi ck~ ness of the inverted intcrval (132 m) is smaller in rela­ lion to the other two intervals because of the overbur­ den compaction and the structural dip of deposits. 4.2. correlation whh on-shore sediments according to their facia l characteristics, off-shore facie s x, a, and b can be com pared to the liburnian and miliolidal limestone (sikic & polsak, 1973; big not, 1972; drobne, 1979) in l stria (fig. 17). 44 susak more 1 gr iii = 2 jaoran-3 gr l e ~ 3 8 4 kornati mor e 4 gr g e n 0 ' [e • . ,@.: 5 o • 0' .iij ~ 6 geologia croatica 50/1 ka te · 1 gr d 7 • 8 o 50 100 150 m vertical scale horizontal : not in scale fig. 16 facies display: i) perit idal deposits: 2) coasthl deposi ts; 3) lidal flat deposits: 4) shallow platform deposi ts: 5) ope n platform shoals: 6) ?bcach deposits: 7) platform margin bu ildups: 8) foreslopc deposits: 9) fl ysc h. however on the koromacno cape in the base or the li bu rni an sedi ments, there are poiimiclic brecc ia coil ­ g lomerates 15 in thick, that arc also in a transgress ive relations hi p to the upper cretaceous limes tone. the breccia conglomerate is complete ly ullsorted, and co i1 tains met re, c1ccimetre and centimetre sized c lasts of the cre taceous and pa laeocene (kozina type) lim estone, and la rge c lasts of thick dark red and orange ca lc it e veins in the calcarenite matrix. o n the los inj island, in the base of the miliolid (m udstonc-wackcstonc and packstone-grainstone) lime­ stone, the re a re al so transgressive breccias, approx i­ mately i mthick, with clasts of cretaccotls limestone. the posit ion o f the breccia conglomerate is ident ical 1'01' bot h o utc rops, so it is poss ible that they were fonned during the same event as the facies x in the off­ shore ad riat ic. on the islands of pasman , ugljan and kornati the facie s 1\, band care reduccd to a thickness of 3 m. mamuzic & nede ladevide (1973) describe this as a tran sg ress ion ex pressed by basa l brecc ias in the " terra rossa" or recl c lay matrix up to 20 cm thick. the unconformity is almost unnoticeable. brown platy lime­ stone that is similar to the liburnian beds, with abu n­ dant small gastropods and mil iolids is depos ited on this transgress ive mate ri al. even this level is not thicke r than 20 cm. the follo wing 2.5 m consis ts o f light brown, sli ghtly chal ky limestone w ith mili ol ids and some gastropods. there is a similar development of the same sediments on the islands of ugljan and losinj. the transgressive contact between the c re taceous and eocene in the ravni kotari area is characterised by a karstified surface with bauxite or by supratidal fenes­ tral and intertidal miliolid limestone virtually concor­ dant with the underlying depos it s (d robne e t a i. , 1991); so fac ies x and a arc reduced (fig. 18) . facies band c arc of similar thickness to those [rom the jad­ ran-9 well (approx. loo m). alveoli na and nummulites limestone o[ the midd le eocene, by the ir sed imentolog­ ica l and biostratigraphic characte ri s ti cs, can be com­ pa red with the sedimcnts of fac ies d, f and g in the off-shore. platform margin lim estone in the we ll s jadran-3 , komati more-4 and katei (figs. 17 and 19) is devel­ oped on the very western edge of the carbonat e plat­ form. the scarse cored samples of th e wire lin e log facies on the buildup , well expressed on the seimic cross sections , do not a llow dete rminati o n of th e reef sens i/ striclo. rccently publi shed papers (dragi­ cev ic e t ai., 1992) and well dat a fro lll the sou thern adriatic indicate that the ree fs are not the exotic c le­ men ts in that area. in the jadra n-3 well the pl at form tari kovaci~: the development of the eocene platfonll carbonates from weill. ,; eustatic curve we l l s , 200 100 0 sm·l ,·3 km · 4 '"' " -•• • .. • z • z u 0 • • 0 ,. 0 • ic , kate · l , 45 outcrops i.korometno2.lotinj ).sliba 4 . u"jan s .hnkovac ii . skt.din _-~i.:,i~ , • -• e:c.5 x ~x~x rs!id x~ x ? ~xi~xi (:ujd x 1 55 • 6. 6' thanetian • ~ u 110.2 ----~ ~ danian : ii .4 h 61111.1981. ~b"c ? ~6'c , ~b"c fig. 17 corrclation o f the on-shore and off-shore deposits. legen<.l : x) perit idal deposits; xi) subfacies of the facies x in the outcrops: a) coasta l deposits: b+c) tidal nat deposits: d) shall ow plalfonn deposits; e) platfonn margin bui ldups: f) fo reslopc deposits: g) open plat­ form shoals: y) ?beach deposits. margin was drowncd during the lulctian, slightly earli ­ er than in other wells, because of the sudden tectoni c subsidcnce. at the same time in the kornati more-4 and katei wells, buildups first migrate toward the land in prograding transgression, and then they were replaced by shoals that indicate the relative shallowing or the sea level (tcc tonic uplift). drowning or the platform beneath the fly sch depos it s is timed by nannofossils at the upper part or the middle lutetian: np~15/16 nan nofoss il zone in (stria, in ravni kotari somewhat laler (np~ 16) and in the split area np17 (benic, 1991). therefore the ear­ bonale sed imcnts or .i3iarritzian age in the katei well can be compared onl y to the sedi ment s sout h of the krka rive r (in the surroundings of skradin), and sou th ~ ern dalmatia (peljesac and cavtat). 4.3. petroleum potential in the eocene limestone oj" the katc ~ i well o il shows were traced in small intervals be tween 20205630 m. in the considered sequence of the eocene lime­ stone, hyd rocarbon shows occur in the intervals 20202086 iii and 2340-245 0 m. part of the interval frolll 2394~2450 m is of crctaeeous age. the rese rvoir char­ actcris ti cs were primarily good (facies g) , but they were com ple tely destroyed by diagene tic processes. the oil appears in poorly connected fractures and vugs (secondary, frac tu j"c and "vuggy porosity"). geochem ical analyses of the oil proved the presence o f su lphur (6-6.8%), and domination of n ~ajkanes . the pristane/phitane ratio is less than 1. the precursor is lhe ke roge ne type 11, lipids of algal and bacterial origi n deposited in a highly reductive environment. the oil from the eocene limestone is characterised by "napht­ eni e hump" on the gas chromatograph, which is not presellt in ihe deeper intervals of the well. this is ex plained by the lower kalagenctie degree or transfor~ mation or by possible oil degradation compared to the mature katagenet ic degree of trans forn1ation evaluated in the oil from deeper parts of the well. it is certain that the oil does not originate from the eocene limestone of facies a. the organ ic matter in the facies a originates from kerogen type iii which is dom~ inatcd by amorphous huminite/v itrinite or a tcrres trial precursor in the immaturc stage of the rmal transronna~ tion. in thc jadran-9 and jadran-3 wells, becausc of the cond ition s in the sedi mentary environment (peritidal cnvironmen t with occasional bracki sh wate r), most of the organic matter is ox id ised. however, in the cretaceous sediments in the j adran ~ 9, jadran~3 and kate-i well s sourec rocks were detcr~ mined that are in the early stage of the the rmal katage~ netic transformation (the beginning of the oil window) that generate oil. the upper cretaceous laminated mudstone of limited extcnt and thickness were deposit~ ed in the anoxic lagoons and conta in heavy isotopes (dc = 22-25%) and kerogen type i and 11. the precur~ sor is the algal~bacterial organi c matter of marine origin from a very rcduced environment, confirmed by the presence of heavy isotopes. the rock is also immature. the lower cretaceous source rocks contain kero­ gene type ii and subordinately type i, in the early stage of ka tagenctic transformation. organic rich lami nated stromatolit ic mudstone was depos ited in lagoons of hi gher sali nity and sabkhas. thi s is confirmed by the pristane/phitane ratio which is lower than 1, the pres­ ence of sulphur rich asphajtene and by heavy isotopes c ~c == 22%). on the gas chromatogram there is also a charac teri st ic " naphtenic hump", the same as ror the oil from eocene reservoirs. com paring the characteri stics of source rocks and oil , it is possible to conclude that oil has migrated into the a rea of katcl well from estimated so urce rocks of the lower cretaceous evaporite-carbonate beds. 46 -"-"-"--"~....'l-i:..::j.._ .jl .jl. ....ll. ....:l -"-"-""" ,, --_ e sm·1 e_ km·4 o gcologj<l croalic:l 5011 fig. 1 ~ palaeogeographic map in lower and middle cuisi<lll, faci es a. legend: 1) peritidal deposits: 2) land. pos it ion of the oljicrops from lhe fig. 17 afc keyed by numbers . 1 -"~ ~ l. .jl ~ ~_ ..:.t.. ,.::l. ...!.t.. -.101.... ~....i£....:f.. -""... ....ll. ..>l. ...:>l ............. l.. ...:l. ....ll...x. ..x.. sm-1.....iol.. ->l. l....:.l ~ $... .....\l.. -"4 ...;l .:l ~ -"~2 o sokm -~~~~ ... 3 fig. 19 palaeogeograph ic map of lulctian , faci es e, f and g. legend: i) shoals; 2) forcslopc; 3) plalform margi n buildups; 4) land; 5) slope. position of iile outcrop from the fig. 17 arc keyed by numbers. 5. summary the paper is a comprehens ive study of the facies characteri stics of the eocene carbonate beds found in the ce ntral adriat ic wells: kate-i, iadran-3, kornali more-i , jadran -9, and susak more-i. considering wireline log analysis it has been possi­ ble to identi fy the wirclinc log-hlcics x, a, b, c, y, d, e, p, g and h. the relevant sedimentary facie s have been de fined based on geo log ical and drilling data analysis of conventional cores and mud cllttings. facies x, characterised by tidal flat sediments, reptari kovacic: the development of lhc eocene phufoml carbon:l1es from wells ... resents the firs t brief e pi sode te rminated by emersion. facies a is thc first member of thc second major trans­ g ress ive sequence with which eventu a ll y te rminates development of the adria tic (dinari c) carbonate plat ­ form. it begins w ith a s treak m arke r horizon within a sedimentary fa c ies cha rac te rised by coas ta l lagoons, marshes and beaches. cyclic alterna tion of band c facies is cha racte ri stic for the tidal flat. facies y is the fin al membe r of the analysed sequence o f beds on the uplifted lstrian platform. simultaneously, the carbonate p latform g radua ll y subsi ded to the south -east (d facies) . with furthe r transg ressions environment s become more dis tal , thus the fin a l membe rs o f the car­ bona te seque nce are formed by barrier bars, buildups and fores lope deposits ( faci es e, r +g). the s tudied beds have been affec ted by tangential tec toni c eve nt s at the e nd of the eoccne pe riod. as a result of rolding ancl thru sting, the eas tc rn part of the studied area is upl ifted , wh ile the weste rn is lowered , thus form ing the dugi otok depression which has been fill ed with fl ysc h and flyschlike depos it s du ring the younger palaeogene and in miocene. beds of the fac ies x have an uncertain s tratig raphic position, younger than the crclaceous but o lclc r than the cuisian. tran sg ress ive sequence fro111 a to y faci es was form ed during c ui sian, whereas the others belong to the lute tian (and biarritzian). in corre lation with surface outcrops the synchronous beds, along the dinaric strike show an al most ident ical deve lopment of the scdime ntary e nvi ronment regardless of how di stant these illay be (the arca of labin in istria and the we ll s ill the adriatic offshore) . much closer sedilllen ts on ihe komal i islands and in ravni kotar outcropping in a perpendicular direc tion to the dinar­ ides arc d iffe rc nt from the offshore sediments both with regard to composition and thickness. acknowledgement the autho r wishcs to thank to the ina's directory having perm itted thc publication o f this study and to g. bu rg eo is , e. balaz, d. stankov ic, d. lucic , g. baric, j. t is lj ar and k. drobne, whose pa l­ aeontological, sedimento logical and geochemical analy­ ses were l1 sed in thi s paper. the author is espec ially grate ful to d. sa rto rio and s . ventur ini frolll ag ip s.p.a. who kindly reviewed the manuscript and provided many val ua bl e sugges ti on s. the specia l thanks to i. vu lama and d. balic who c reated crossplol displays. 47 6. references bab ic, lj . & z upan ic, j. (1979): uloga ant ago­ ni s ti ckih procesa izgrad nje i razgradnje grebena u povijest i porozite ta ~ primjer paleocenskog grebena u banij i.geoloski vjesnik, 32, 33-45. benic, j. (1991 ): the age orthe istrian tlysch deposits based on calcareous nannofoss ils.in: drob ne, k. (cd.): 2 nd m eetin g early palaeoge ne benthos, igpc-286, guide book, pal. ins!. i. rakovee, ljub­ ijana, 24-25. bignot, g. (1972): recherches st rat igraphiques s ur les calcai res du cretace s uperi eur e t de l 'eocene d ' istric e t des regions voisi nes. essai de revision du liburnie n.travaux du lab. micropaleontologic, 2, 343 p. dav is, r.a. (ed .) ( 1985) : coastal sedi mentary envi ­ ronmcnts.spri nger-verlag, new york, 716 p. drag icev ic , 1. , blaskovic, i. , tisljar, j . & benic, j. (1992): stra tigraphy of pal aeogene strata wi thin the mesihovi na rakitno area, western i-i e rzcgovina.geologia croat iea, 45, 25-52. drobne, k. ( 1979): palaeocene and eocene bed s in the sw slovenia and istria. 16th europ. mie ropa l. coil. , excursion guidebook, ljubljana, 24 -25 . drob e, k. , vlal-l ovic, i. , trutin, m. , pa vlo­ vec, r. , cosovi c, v. , bab ac, d. , c i mer~ man, r. , luc ic , d. & pa vsic, j. (199 1): excur­ sion b ravni kotari palaeogene.in: vla ho­ vic, i. & vellc, i. (cds.): 2nd sympos iu lll on the adriatic carbonate pl a tfo rm , excursion g uide­ book. institute of geology, zagreb, 53 -105. elloy , e. (1982): ree f reservo ires from the middl e devonian of northern alberta, canad a.in: r eeckma n, a. & friedman, g.m. (cds .): explorati on for carbonate petrole um reservo irs. wiley-interscicnee publica tions, new york, 2 13 p. embry , a.f. & klovan, i.e. ( 1971 ): a late devonian reef trac t on northeastern banks is land , northwest territories.can. pe trol. geol ogy bu ll. , 19,730-78 1. fertl, w. h. (1979): gamma ray spectral da ta ass ists in co mplex formati o n eva luation.tran sac ti ons, s pwla 6th europea n eva luation s sympos ium , london, 1-35. g ho se, k.b. ( 1977) : pa leoecology of the cenozoic rce fal foraminifers and a lgae a bree t' review.­ pa laeogeography, pa laeocli ma tology, palaeoecoio­ gy, 22, 23 1-256. haq, b.v., hardenbo l, j. & vail , p.r. ( 1987) : chronology of fluc tuating sca lcvels s ince the trias­ sic .science, 235, t 1561167. klappa , c.f. (1978) : biolithogenesis of mi crocodi ­ lim: e lue idati oll .sedimcnto logy, 25, 4 89-522. 48 laporte, l.f. (ed.) (1974): reef in time and space. selected examples from the recent and ancient. ­ soc. of economic paleontologists and mineralo­ gists, spec. pub., 18, 256 p. lucic':, d. (1993): mikrobiostratigrafija naslaga oko granice kreda tcrcijar srednjejadranskog pocl­ morja.unpublished m.sc. thesis, university of zagreb, 68 p. mamuz](':, p & nedela-devide, d. (1973): osnovna geoloska kart a jugoslavije, i: 100.000. tumac za list biograd k33-7 (geology of the biograd sheet).[ns1. geol. istraz. zagreb (1967), savezni geol. zavac! beograd, 27 p. schlager, w. (1981): the paradox of drowned reefs and carbonate pjatforms. oeo!. soc. of america bull., 92/1, 197-2lj. geologia croalica 50/1 selley, r.c. (1985): ancient sedimentary environ­ menls.cornell univers ity press, ithaca, 317 p. sikic, d. & polsak, a. (1973): osnovna geoloska karta sfrj, i: 100.000. tumai' za list labin l33101 (geology of the labin sheet).[ns1. gool. istraz., zagreb (1963), savezni geol. zavod, beograd, 55 p. toomey, d.f. (cd.) (1981): european reef models.­ soc. of economic paleontologists and mineralo­ gists, spec. pub., 30, 546 p. wilson, j.l. (1975): carbonate facies in geolog ic history.springer-verlag, new york, heidelberg, berlin, 471 p. manuscript received march 3, 1995. revised manuscript accepted september 11, 1996. g e ol. c ro a t. 49/2 295 298 l tab. 2 pis. zag reb 1996 scicllf{j ll' /l o l e effectiveness of the acidizing treatment in wells based on the petrographic results of thin-section acidizing experiments ncvcnka ras ka.j . edita gasl.jevic-mil.jo vski and mclika hot-grg ic proceedings key word s: acid izing treatment in th in sections, petro­ graphic analyses, solubility of minera ls. abstract the ac idi zing (reatment is a method usuall y used for ihe cnhacc ­ menl of produc tivi ty i ll o il-gas fie lds . treati ng thin -sec ti ons for microscopi c pe trog ra phi c anal yses wit h comm on acid s, establishes the so lubilit y and dispersion o f minerals, as wel l as secondary forma­ tio n damage. the best res ults were achieved by treating carbonale rocks and rocks wilh carbonate const ituents. si liceolls minera ls, such as q uart? and micas arc noi dissolved, but the sol ubili l}' o f fe ldspars illcreascs w ith the col-component in plagioclase ,md thc dcgrce or al te ra ti on. cl ay minera ls ,tre s ubj ect 10 mec hanica l d is integra tion w hic h causes furlher fo rmation damage. anhyd ri te hnd o paq ue min­ e ral s arc insolubl c. j. introduction th is method cont ri butes to the beller understand ing o f the effec tiveness or the aci dizi ng treatm ent in well form ati ons , by using lhe ac idi zed th in-section s [or mi croscopic pe trographi c analyses. no simila r method has been round in ihe literature. dependi ng on the m inera l composition, th in-sec ­ ti ons were ac id ized with hydrochlori c ac id and with a mixture o f hydrochloric and hydro fl uo ric ac ids which arc mostly useel for treat ment (bi. hug hes inc .• 1972; farley e t a i. , 1970; gdansk i & shuchart. 1996) . the main reason fo r thin-section ac idizing is the variabl e minera l com positi o n of secti o ns w ithin the same roek sample. with ac idizi ng treatment o r thin-sec­ tions the solubility o r minerals is di rectly demonstrated as well as the secondary effects caused by the acids. al though this treat ment is mainly llsed for enhanc­ ing permeabil ity in sedi menta ry rocks, metamorph ic and effusive rocks were a lso ircaled . a few examples from the result s are represcntcd. 2. procedure t hin sections were prepared fro m the rocks o f dif­ fe rent wells (i.e. di fre rent types of sandstones, dol omite wi th anhydr ite, andes ite-basalt and garnet miea schi st), using convent ional meth ods. an acidproo [ resin was kljucnc rijeci: kise li nska obracla mikroskopskih izbru­ saka, pe trogra[ske ana lize, topi vost mineral.:l. saictak kiselinska obrada st ijcna je metoda koja se kori sti za pobo ljsanje prod uktivnos ti naftnoplill ski h po lja . trc ti ranje m izbru s.tka za m ikros kopskc pct rografske ;lnali zc odgovarajucim ki sc linama ulvrdcna je topivo sl mincra la kao i nak nadna o.~ t ccenj a ro nn acija . naj bo lje rezultalc topivost i po kazuj u karbo na ti. s ilika lni m inera li poput kvarcil i linjaca su nelopiv i, dok se topivost fe ldspata povecavil sa sadri ajern ca u plag ioklasima i st ll pnjem aheracija. topivosl g tina je upilna zbog nj ihove dis pe rzivnosti u dod iru s otapalom. anhidrit i pi!" it sli nc topivi. chosen [or preparation. t he samples were treated under laboratory condi tions, according to standard methods for so lubil ity (api-56) where the temperat ure, the time o f treatin g, type and concent ra ti on of ac id we re sa ti s­ fied , whi le the press ure and infl uence of pore fl ui ds were not. for thin-secti on ac idiz ing two acid so luti ons were li sed which arc [requently practiccd in laborato ry or ina naft aplin : 15% ii ci fo r carbonates anel 3% hf + 12% il e l for silica tes. each thin sect ion is separa te ly immersed in the appropriate heated so lution dependi ng on the mineral composit ion at a temperature o f 60°c for approx imately 30 minutes, hnd then immediate ly micro­ scopi cally re-analyzcd and pho tographed , so ih al the influ ence of ac ids on the minera ls can be de te rm ined . this procedure was app lied for ihe first lime in the lab­ oratory o f ina-naftaplin. 3. res ults comparison of the petrographic analyses is given on table i. it is obvious that metamorphic rocks predominantl y composed of quartz and micas are prac ticall y insol uble (pl ate i, fig. 1). pene tratio n o f ac ids is onl y poss ib le a long the open or carbonate cemented fractures. this is con fi rmed in the griz well , where the increased pro­ ducti vity aner acidizing is mainly connected wi th disso­ lu tion of the carbonate reservoir rocks. ina-nartaptin, laboratory re ... earch dept., lovinciccva [ . hrl0000 zagreb, c roa ti.l. 296 minenlls quartz k-fcldspar plagioclase micas clays sulfates (anhydrite) pyrite calcite, dolomi te solubility in 15% hel no no high solubility in 12 % he l + 3%hf no low to moclerllle low to high no low 10 moderate? no high table i so lu bil ity of mi neral s accordi ng 10 restllts or pctfo,graphic analyses. th e solubility of fe ld spars increases with the ca­ component in plagioclase and the degree of alteration. thi s is well docu me nted by microph otog raphs of tra­ chyancics itcs (pi. i, fig. 2), from the oil fi e ld c rnac, so the aciciizi llg treatme nt should probably improve reser­ voir productivit y. t o e nable the correct determ ination or c lay solubi li ­ ty, additional sem anal yses arc recomme nd as the magnification or the petrographic mic roscope 's optical sys tcm is too low, anci further morc c lay min era ls arc subject to mec hani ca l disintegration and d ispers ion in contact with solut ion. this propcl1y of pclit ic sediments ve ry oft en cause formatio n pluggin g (13j. hug h es inc ., 1972). carbonate m incrals show an exce llent reac­ tion wi th the 15% i-ici sol ution whethe r as prim ary o r secondary constituent s in rocks (plat e ii ). anhydrite is not di ssolved in 15% he l, but associated wit h dolomi tc it dis integrated afte r the dolomite dissolved (plate ii ). ac idi zing sand stones en larges the po re space and inc reases the produc ti vi ty of the reservoir, bu t a lso destroys the roek tex ture. wi th hci a ll carbona te com­ pone nts (ceme nt and dc tr itus) are di ssolved (plate ii , fi g. i ) . hyd rofluori c ac id partly di ssolved and di s­ persed both the c layey matrix and coating . " matrix geologia cro:tlica 49/2 free" insoluble g rains may be re leased and collapsed, causing the i"onnation damage. opaque minerals c.g. pyrite and il menite are mainly res istant (plate j). 4. conclusions and recommendat ions the result s indi cate th at ac id izing treatm e nt wi th hydrochloric acid is complete ly sufficient for carbona te rock s, and in clastic sediments cemented by carbonates, as we ll as for clastic sedime nts wi th high co nte nt s o f carbonate de tritus (rock fragments, foss ils, e tc .), i. e . in li th ic a re ni tes, calc li th ites and calcare nites . in "'dirty" sand s tones (g raywac kcs) w ith a m at rix mainl y com ­ poscd of a mi c roc rys ta lline aggregate of quart z and seri c it e , c lays, sodic plagioclase e tc. ac idi z in g with mixture of hydrochloric and hydrofluoric acid seems to be rather ineffective than useful. th e acicii z in g treat­ me nt is a lso recomme nded in s tron g ly tcc tonized nonsedimc ntary rocks with a hi gh fracture porosi ty o r with ves ic ul ar " porosity" as in e ffus ives. ror the compre he ns ive e ffec tiveness o f <lc idi z ing trea tme nt is important to be famili ar with the mine ral composition , s tructure and tex ture of the roc ks and to usc the described procedure for checki ng the e frec ts 01" solub ility on treated rock w hereve r possiblc . 5. references bj h ugi-ies inc. (1972): engineered stimulation, vol. 11.b1 hughes inc., houston , 5-23, 84-92. farley , j.t. , mill er, b.m. & schoelle, w. ( 1970): design crite ria ror matrix stimulation with hydrochloric-h yd ro ouorie aeid .j. pe t. tech., 22, 433-440. gdans ki, r.d. & sc huchart, c.e. (1996): new­ ly discove red equilibrium controls hf stoichiome­ try. 1. pet. tech. , 48, 145149. plate i fig. i garnet m ica schist (crossed nicols). a) thin section be fore treatme nt (q-quartz, pig-plag ioclase, py-pyrite . t -micas); b) the re are no visib le changes on minerals after ac ieii zing trea tment ( 12% hel + 3% h f). fig. 2 trachyandesite (crossed nicols) . a) phenocrys t and mi crolites are composed of plagioclase with potass ium feldspar (pig+ k-fi); b) al l mine rals arc dissolved (12% i-ic i + 3% hf). plate ii fi g. 1 foss ilife rous sandstone (li tharenite) (c rossed nieois). 0) det rital quart z (q), plagioclase (pig), lith ic frag­ ments (l-fr) and foss il remnants (f) with calci te ccmc nt (cac); b) only the carbonates (detri tus and cement ) arc dissolved (b lack space). ac idi zed wi th 15% hci. fi g. 2 dolomit e with anhydr ite (crossed nicols). a) anhydrite (an h) , dolomite (dol) ; b) dolomite is di ssolved (black space), ancl anhydri te is di spersed. aeidized with 15% hc i. raskaj, g:lsljcvic-miljovski l~ ! !ol-grgic plate! 297 before treatment after treatment 298 plate ii geologia cl'oalica 49{2 before treatment after treatment geol. c ro at . 50/2 269 278 9 figs. 6 tabs. zagreb 1997 glaciation traces in the area of the risnjak mountain massif andrija bognar and ivanciea prugovecki key words: glac iatio n, cirque, terminal depress ion, g lacial va ll ey, moraine, erratic blocks. abstract the arca of the risnjak mountain massif is a submorpholog ical region p.u'\ of the mcsomorphological region of the soulh-western gorski kolar. thi s area exceeds 1,500 metre.s in height. in [he rel ie f st nl clurc of the mass if, the system of ranges and erosion surfaces pla[c:l tla , has been formed on the folded-b lock, mostly carbonate base by subsequent microicclonic activity and cxomorpholog ical proccsscs. such relationships of relief under conditions of exceptionally low icmpcnl1ul"cs and abundance of snow prec ipitat ion during th e pleis­ tocene, were prerequisitcs for the developmcnt of gl'lcialion. glacia­ ti on or the mountain massif was marked by formation or the valley, pl>ltchu and cirque glaciers, wh ich is proved by the discovery of gla ­ cia l moraines and othcr morphological features and correspond ing sedimellt s. i. introduction .1. t ile research problems th e problem of the pl eis tocene g laciat ion of the dinari c mountain system in croatia is one of thc most int crest ing gcosc ientifie problems, and one which has intri gucd o ther natural sc ience disc iplin es, espec iall y bio logy, and has drawn the attention of many natural scient ists during the 20th ccntury. g laciation was mentioned for the first time by hr an ilovic ( 1901 ) as one of the possible means of forma tion of the drciniea plain. gay azzi (1903) wrote about the southern velebit glaciation, and based hi s assumptions upon research on the mala and veli ka pakleniea pla ins. schubert (1909) produced the first concre te data in his speech about the southern velebit glaciation. a german geomorphologist bauer ( 1935) deta iled the problems of the jezera area in northern velebit, and thought that the pleis tocene snow-line on department of geography, faculty of science, univers it y o f zagreb, maruliccv irg 19/11, iir1 0000 zagreb, croatia. the vclebit mountain had been somewhere between 1,400 and 1,500 m above sea-level. a hungarian biologist degen (1936) and geomor­ pholog ist milojevic ( 1922) a lso wrote about the velebit glaciation. pollak ( 1947) had the opposite opin ion. he negated the possibility of veleb it g lacia­ ti on. pollak ( 1947) declared that there were s now­ waters which fill ed some bigger sink-holes of the upper part of velebi t. the geographer rog ic (1957) thought similarly. the most recent research (nik ler, 1973 and bel­ ij, 1985) proved the existence of glaciation in southern velebit. and the research of sokac et al. ( 1976) and bognar el al. (1991) achieved the same in northern velebit. furthermore, other authors also wrotc about the possible glaciation of particu lar mountains in croat ia: milojevic (l922) wrole about the glaciers of troglav on the dinara mountain; sifr er (1959), a sloven ian geomorphologis t , wrote about glaciation of c roatian snjeznik. pla tak and obruc; rldanovic wrote about glaciation of orjen ( 1962, 1966); mihllevic (1995) about the possible ex istence of ci rque glac ie rs on the upper reaches of the ucka mountain , and cecura (1995) publi shed on the g lac iation or the kamesni ca and dinan! mountains. 1.2. ti-ie study area the study area of the risnjak mountain massif, and part of the croatian snjeznik mou ntain range is a com­ ponent of the outer dinarides mountain zone in the sel­ ting of the megageomorphological reg ion or the dinaric mountain system. the rcseare h was conducted within the fo llowing boundar ies: from gornje jelcnje in the south to gerovo in the north, [rom the croat ian snjcznik mountain range in the west to crni lug in the cas t. the study area cov­ ers approximately 100 km' (14°35' 14°42' e; 45°23'45°30' n) (fig. 1). the largest part of thi s area is protected as part of the "risnjak" national park (64 km'). this paper was presented at the scientific meeting dedicated to the 80th anniversary of the life of professor milan herak , held on march 5th, 1997 in zagreb 270 ...... 0" ..... ..... . ... ........ . r1jeka ........ " .. ..... " """" "'. 0" ." '. ' . . ..... . gerovo :'; ~ ........ . '1ii:t '. ........ . v._ "" delnice 10 fig. i geographical position of the study area of the risnjak moun­ lain massif. 1.3 . some basic geomorpho logical and geolog ical characferistics of the risnjak mountain massif t he risnjak mountain massif represents a submor­ phological regional un it of the mesogeomorphoiogicai regio n of the nort h-weste rn part of gorski kolar. the study area has been somewhat widened, so it includes a part of the subgcomorphologicaj unit of the croatian snjcznik mountain range. the risnjak mountain massif is div ided into a series o f geomorphological microregions: the mountain range o fv eliki risnjak ( 1,528 m) and mali risnjak ( 1,448 m); the mounta in range of janjicarski veh (1,3 14 m), vc liki bukovac ( 1,266 m) a nd mali bukovae (1 ,263 m ); the mollntai n rangc or velika !iija (l,172 m) and mala sija ( 1,149 m); the ostra mountain range (1,221 m) , the segi nscek mountain range (1,145 m), the uvala lazac ( 1,060 m), a seri es o r uvalas at gasparae (940 m) seg ine (950 m), the li va la lividraga (918 m) and th e plain of the suha retina river. si milarly, the mountain range of croalian snjcznik can be divided into a series of microrelie f units, and th is wo rk dea ls with the radesevo high mounta in e rosion surface. the risnjak mountain system is characte rized by a folded-blockcd-ovcrthrusled geological structure . acc­ ordingly, it fall s under the type of conforming morpho­ slruc turcs (bogna r, 1987a, b). in the regional geological structure of the wider area the oldest deposits are permian, represented by an alte r­ nation of shales and sandstones. lower triass ic sandy dolomites, containing in tercalations of sandstones, ove­ rlie the perm ian c las tics. m iddle triassic deposi ts a rc missing and upper triassic terrigeneous clastics and/o r dolomit es unconformab ly follow th e lowe r t ri ass ic dolomites. karstified jurassic carbonate rocks predomi­ nate within the " risnjak" nat ional park. they are rep­ resented by shallow marine limestones of the dinari c carbonate plat form, some of which (part ic ularly those geologia croatica son n 8 w e fig. 2 transverse profite of risnjak (n-s, w-e). of early jurass ic age) , show latc diagene tic dolo­ mitisation.middle and late jurass ic carbonates are pre­ domi nan tly limestones. the quarternary is rep resented by the pleistocene and holocenc sed imcnts (sa vic & dozet, 1984). t he investi gated area is cha racteri zed by fo lded­ fau lted tectonics. in places (gerovo, suha recina) there are som e struc tures whe re the permian and t ri assic de posits ove rthrust various s trat ig raphi c members of the jurass ic. in its neotectoni c deve lopme nt stage the dinaric platform experienced intensive fau lt disarrange­ me nts (verti cal-s ubve rtical fault s), which, globa ll y, resul ted in uplift of the whole serics o r blocks. in rclief they appear as chains of mountain ranges and m ass ifs. one of thcse blocks is the block-massi i' of ri snjak where faulted tectonics predominates. on a dom inantly carbonate base of limestone and dolomites, a compound orographic structure has been foml ed. a se ries of range e levations can be s ingled out (the range of vclik i and mali risnjak etc. see the microgeomorphologieal d ivi­ sion) as well as a series of little uvalas (fig. 2). among the range elevati ons of the ri snjak m assif we can see an older erosion surface (smrckovac), whi­ ch was additionally microtectonically broken and today has the characteri stics of a plateau which has been, by exogenic morphological processes (corrosion and gla­ cial processes), formed into a hilly region charac le rized bognar & prugoveeki: glaciation traces in the area of the risnjak mountain massif 271 [][] ~t"'" [it] tewitw. depre&sion [qj ~ [qj <jroih)-'[qj :u«'~wilhel£vat1on!i [qj ..-w.0!i,""",,1nai.~ d i'nnw..l.you'mol'eoi'iiotfw.-.oiioe [2] lateral.loioaai<~ j) b:j erratic ... oao:s ej slib-oi.acwj.y eroded s'ru'$ ::':\ \ aiz2j ~~~ '7 ~ [gj oueersferu~aaea by the interplay of deep glacially remodelled dolines, escarpments and more or less erosion surfaces. 2. geomorphological traces of glaciation mapping of the area of the risnjak mountain massif ascertained for the first time the corresponding geomor­ phological and geological traces of the pleistocene glaciation (fig. 3). 2.1. glacial relief forms the glacial forms in the area of the risnjak moun­ tain massif developed during the activity of four glaci­ ers, three descended from risnjak mt. and one from the sloven ian sneznik ml. the sources of the so-called risnjak glaciers are the smrekovac and radcsevo (cro­ atian snjeznik) plateau and the range ofveliki and mali [zj <'li.i"':u'''''~iirect1on fig. 3 glaciation traces of (he ris­ njak gorski kotar region. risnjak, while the source of the so-called sneznik glac­ ier was the plateau at the foot of the slovenian sneznik (table 1). the glaciation traces include the existence of glacial erosion (cirques, nunatak, sub-glacially eroded steps i, terminal depressions, glacial valleys) and accumulative (moraines, erratic blocks) glacial relief forms. 2.1.1. glacial erosion fonms in the risnjak region, the glaciers source area is rep­ resented by systems of glacially remodelled dolines cirques, which were mutually connected by ice in the pleistocene. smrekovac is an "older" erosion surface which was later microtectonically broken, and today has the fea­ tures of the plateau formed by exogenic processes (pri­ marily by glacial and corrosion processes). this is a more-or-less hilly region characterized by the interplay of deep glacially remodelled dolines 2, escarpments and uneroded parts of the erosion surface. the whole smrei sub-glacially eroded steps are destructional fonns developed by selective glacial erosion. 2 glacially remodelled dolines are pre-glacially fonned sink-holes being filled with ice and snow during glaciation. ul lieologl:t croatlci ciuil glacier glaciation time length in km radesevo podcajtige radesevo lazae radesevo gasparae smrekovae segine zelinski lug smrekovac sijska cesta zelinski lug siovenski sneznik lividraga siovenski sneznik mali klanac siovenski sneinik gerovo late worm late worm late wurm late wurm late wurm late wurm 2.5 4.5 7.0 5.5 7.0 18.0 22.5 24.5 table i es(ima(cd icng­ ths or the g laciers in (he area of the ris­ njak mountain mas­ sif, of (ile croatian snjeznik mountain range and slovcnian sneznik. worm older worm or riss kovac area is situated 1,150 m above sealevel (above the pleistocene snow-line) and is, considering its relief, open towards the north (fig. 4). radcsevo today a plateau (erosion surface) on the mountain range of croatian snjcznik, like smrekovae represents a system of glacially remodelled dolines and escarpments, but located higher above sea-level (over 1,200 m). these dolines cirques, considering relief, are "opcn" towards thc cast and north-cast (the ice "was flowing" towards the uvalas lazae, gasparac and segi­ ne). the glacially remodelled dolines cirques, were pre-glacially formed by corrosion, but by the activity or ice, mellwater and snow-water they were deepened and widencd, and today their depths vary from several tens oj" metres to 209 m (viljska dol ine). particular cirques­ dolines arc a hundered metres in width. in the pleistoccne bctwcen the accumulation areas of the risnjak and snjeznik glaciers, the sjeverni mali ri sn.iak veliki risn.iak juzni mali risnjak range, most probably stuck out above the ice like nunataks, among the plateau glaciers formed on the smrekovac and radcsevo plateau. proof that the very summit oj" risnjak was above the ice includes the periglacial rock erosion and microrc licf dissection which couldn't be possible if the area had been under the ice (fig. 5). cryofraction produced rock cracking, rock-fa ll , stone stripes and migrating turfs. except in the topmost parts, h g. ~ t\ \ u; w rrom the :-,ulllllli( or vdd,i risllpk lowards the ea.\i. 011 a part of (he system of the glacially remodellcd dolines cirques of smrekovac. such microrclief dissection can '( bc found either on the smrekovac (excluding bijele slijene) and radcsevo plateaux, or in the systems of the lazac, gasparac, seg­ inc, zelinski lug uvalas-terminal depressions, and gero­ vsko poljc. in molion, icc with eroded material encounters dif­ feren t obstacles and forms the so-called sub-glacially eroded steps. these forms have been establi shed in fron t of the terminal depressions and moraines (podca­ jtige, gasparac, sijska cesta, zeli nski lug, etc.). fur­ thermore, in addition to glacial erosion, the sub-glacial­ ly eroded steps between particular s in k-ho les were remoulded by corrosion processes. with regard to lhe fig. 5 a gbci.dly i\;modcllcd dolinc ill uppcr part of v..:111-..1 i<1.\ii.i'ii-... with periglacial stone stripes and blocks at the bottom. l30gnar &. prngovcl:ki ; (j1;lc i;ltion traces i ii the 1\ rea o f the ri snjak mountain massif ri g. 6 r\ lenn ill;ii dcprcssion with <in cit,l1ic block (forcgrollnd) and 1he f"rontalmoraine in segine (in the background). chicfly carbonate structure and strong corrosion proce­ sses, it is understandable that the traces of the glaci a l striae (furrows) and of the icc smoothed surfaces have not been found. each of the four quoted glaciers has formed glacial vall eys . these are documented at least in part by the "u" shaped transverse profile. this especially relates to the podcajtige glacial valley and the glacia l va ll ey of the sn eznik glac ier north-east and north-west from lividraga. two glac ial va ll eys on the smrekovac pla­ teau arc not so prominent (the sija glacier va ll ey and the gasparac glacial valley). they represent linear elon­ gated valleys marked by a series of dolines-cirques, mutually divided by little sub-glacially eroded steps. terminal depressions represent glacial erosion for­ ms surrounded by frontal (final or terminal) moraines. th ey are shallow, by glacia l erosion deepened areas where the glaciers melted. their final forms appeared aner th e outflow of meltwater. terminal depressions, today karst uvalas lazae, gasparac, segine and livi­ draga were formed in basic rocks (in the jurassic lime­ stones: dogger and maim lazac; in the jurassic lime­ stones : maim , and tri assic dolomites: late triassic seg ine; in the jurassic dolomites: lias and jurassic limestones: maim lividraga; sayle & dozet, 1984). they are of different dimensions: lazac 900 x 700111, gasparac 600 x 500 111, liv idraga 800 x 750111. as a rule , terminal depressions arc full of glacial accu273 mulative material (from 2-5 m diameter blocks to sill with diameters [rom 0.01-0.05 mm), and partly of riu­ vioglacial material (chiefly subangular, from 2-4 mm to approximately 20 em) (fig. 6). till or glacial material is very poorly sorted. f luvioglacial material is connected only wilh terminal depressions and sometim es appears in fragments. it is thought that the majority of flu ­ vioglaeial material is to be found outside the studied area,jn the direction of the river kupa plain. 2.1.2. accumu lation forms of glacial relief when a glacier reaches the equilibrium-line bet­ ween the ablation/accumulation of icc, melting begins as well as the accumulation of the eroded material whi ­ ch forms frontal (final or terminal moraines). drumlins and kames haven't been observed. \ve can distinguish accumulations of the ground, end and frontal or terminal moraines. in the risnjak area, examples of the ground moraines include: podca­ jtige where the ground moraine appears in two forms one with elevations and depressions (the eastern side of the glacial valley), and another with errat ic blocks (the western side of the g lacial valley); the lazac ground moraine, segine moraine and a series of ground mora­ ines at lividraga. in mali klanac the ground moraine has fallen in, probably due lo road excavations, so its structure can be seen clearly. like till , in the previously mentioned terminal depressions, compositionally mora­ ine is represented by a very heterogenous materia l, from blocks (wi th diameter of 1 m) to silt. frontal or terminal moraine has the form of an elon­ gated (zelinski lug) and half-moon (gerovo, gasparac, lazae, lividraga and segine) wall (deposit) surround­ ing the terminal depression. the gasparac frontal moraine was made by a glac ier the source of which was probably in the area of the modern radesevo plateau. the moraine is covered with vegetation and is 250 111 long and 150 m wide. the glaciers from the smrekovae area formed two moraines: sijska cesta (dimensions 500 x 300 m) and the largest, probably terminal mora­ ine of the risnjak glaciers zelinski lug (1,800 x 500 m) (fig. 7). the ice which "was nowing" from the siovenian sneznik, formed a series of frontal moraines of different dimensions: between lividraga and gerovo (the frontal moraine lividraga 1,000 x 150 m, the fro­ ntal moraine at the foot of seginscak: 600 x 300 ill). r ig . 7 the zel insk i lug fronlal moraine wilh lhe mascnicak terminal deprcssion. fig. 8 a profile of the frontal moraine in gerovo. typical heteroge ­ nous lilt where huge blocks of several hundreds of kilograms mix with tiny karst material. the gerovo terminal moraine represents the final reach of the sneznik glacier and forms a wall 500 m long and 300 m wide (fig. 8). in the glacial material in the livi­ draga doline and in the area of the fron tal moraine dis­ cove red in gerovo, a somewhat greater proportion of dolomites has been noticed. it can be explai ned by a greater volume of dolom ite in the structure of the slo­ venian sneznik area. between lividraga and gerovo, the sneznik glacier also formed a lateral moraine, abo­ ve mali klanac. all moraines are today covered with vegetat ion, which is probably the reason for their late discovery. erratic blocks represent the moraine material which is, because of its large dimensions, often accumulated in terminal depressions or in glacial valleys. examples of these can be found in the terminal depression gasparac and segine, but the largest examples of erratic blocks have been fo und in the area of frontal and ground moraines of lividraga. erratic blocks are main­ ly composed of the limestones (jurassic limestones). their mass exceeds several tens of tons. the relative roundness of the erratic blocks shows eros ion as the consequence of transport (fig. 9). 3. palaeoclimatic reconstruction bcsides re lief condit ions the climatic ones had a great influence on the development of glacial processes. here we shall primarily regard the air temperatures and the quantity of precipita tion. as a base for reconstruc­ tion of the palaeoclimate of the risnjak mountain mas­ sif, we have taken the data of the following meteorolo­ gical stations: delnice (698 m of the height above seafig. 9 erratic block near lividraga (its mass exceeds several lens at tons). level), lokve-dam (723 m above sea-level), parg (863 m above sea-level), lividraga (935 m above sea-level), and data of the totalizer on risnjak (1,420 m above sea­ level). the air temperature and the quantity of precipi­ tation were observed in the period from 1981 to 1994, and the average values relate to that period. the excep­ tions are the meteorological station lividraga which stopped working in 1984 and the data of the totalizer on risnjak for the period 1963-1993. 3.1. palaeotemperatures on the basis of poser's mathematical reconstruction for the pannonian plain ', klein (1953) calculated the average monthly and annual temperatures or zagreb during the maximum of the worm glacial. the differ­ ence between poser's (1947) and klein 's (1953) reconstruction of the temperatures are presented in table 2. the temperatures for the meteorological slations of the risnjak area (table 3) have been calculated on the same principle (taking into account differences between today's and the wilrm temperatures of zagreb). it is necessary to point out that this reconstruction is based upon taday 's relief forms and altitude relations which were considerably changed in the wlinn because the sea-level was about 100 metres lower. a greater degree of continentality conditioned lower air tempera­ tures, and the ice itself wi th its mass and thickness in the top part of the risnjak mountain massif, caused a decrease of the air temperature. in order to get a more complete picture of tempera­ ture relations today and in the wurm, the average annu­ al temperature of the veliki risnjak summit has been calculated for today and for the age of the last glacia3 having observed the intensity of the frozen soil melting in the pannonian plain, poser (1947) calculated the average monthly air tempera­ tures during the wunn g lacial. the average annual temperature amounted to -2.0°c, which shows that in the pleistocene the pannonian plain belonged to the periglacial zones. later research of peesi (196 1) in hungary, kaiser (1961) in the neighbourhood of belgrade, malez (1965) in slavonia, bognar (1975, 1976) and zeremsk i (1977) affirmed the results of poser 's analysis. uogllar & 1'lligovccki: gbeiation t",ee.~ in the area of thl! ris lljak mountaill massif 275 zagreb ii iii iv v vi vii viii ix x xi xii year today 0.6 2.2 7.4 11.3 16.2 19.3 21.5 20.7 16.8 11.7 6.2 2.8 11.4 wqrm -13.0 -12.0 -8 .0 -3.0 3.0 8.0 11.0 9.0 3.0 -2.0 -8.0 -12.0 -2.0 differ. 13 .6 14.2 15.4 14.3 13.2 11.3 10 .5 11.7 13 .8 13.7 14.2 14.8 13.4 table 2 differences between mat hettlalical temperature reeonstntc ti on of the max im um wurm and iod3y's tempe ratures or zagreb, arter bog­ na r el oil (199 1). ii iii iv v vi vii viii ix x xi xii year oelnice today -1.3 -1.7 2.4 6.9 11.6 14.6 17.3 16.9 13.3 8.8 2.9 0.2 7 .1 wurm -14.9 -15.9 -13 .0 -7.4 -1.6 3.3 6.8 5.2 -0.5 -4 .9 -11.3 -14.6 -6 .3 lokve-dam today -1.7 -1.8 2. 1 5.7 10.8 13.9 16.8 16.2 12.7 8.1 2.7 -0.1 7. 1 worm -15.3 -16.0 -13.3 -8.6 -2.4 2.6 6.3 4.5 -1.1 -5.6 -11.5 -14.9 -6.3 parg today -1.2 -1.7 2.3 5.8 10.9 13.7 16.9 16.2 12.7 7.9 2.5 0.1 7.2 worm -14 .8 -15.9 -13 .1 -8.5 -2.3 2.4 6.4 4.5 -1 .1 -5.8 -11.7 -14.7 -6.2 lividraga today -3.7 -4.5 0.9 4.0 8.9 12 .5 15.4 14.0 12.0 7.7 1.0 -1.1 5.8 worm -17.3 -18.7 -14.5 -10.3 -4.3 1.2 4.9 2.3 -1.8 -6.0 -13.2 -15.9 -7.6 tabl !.! 3 average month ly (md annua l air temperatu res ror the meteorological stat ion~ deln ice, lo kve-dam. parg and li \' idraga ( 19r 1-1994 and ihe la~1 19r i -1 984) loday and during the wiinn glac iation. tion by mea ns of the verti cal temperature graciienl 4 (table 4). 3.2. palaeoprecipitation using thc samc actua li sm principle according 10 which today's clima tic c ircum stances arc the key for reconstruction of the climate in the past, the quantity o f prec ipitation can also be calcu lated. on a map o f europe, kle1n ( 1953) presents the quantities or pre­ cipiullion during the maximum or the worm glacial rc latedlo today's quantity. differences for the area of the ri snjak mountai n massi f w~s ~bout 70%, i. e. the quantity of precipi tation was abollt 30% less crable 5). over the broader risnjak region, precipitation has been measured by mcan s of a classic rain-gauge , and the quoted values obtai ned in that way. by use o f a rain-gauge with a net (in the ve1cbit area zavizan) the average value increases ror 249% (kir igin, 1967). ir we suppose that the increase on ri snjak was approx i­ matcly the same, the quantity of precipitation would be as prescnted in table 6. very low temperatures in the pleistocene, and a lar­ ge amount of precipitatio n (main ly data of the raill gauge with a net) had a significanl influence on the deve lopm ent of glacia l proccsses. when we take into account the nort hern exposure, and great relie r dissec­ tion o f ri snjak, it is understandable that there were a ll the necessary conditi ons for the acc umulation or large quantiti es or ice, which, while moving, produced a seri ­ es of accumu lative and erosive g lacial featu res. 4. nle pleistocene snow-line for the area of the risnjak moun tain mass if the pleistoccne snow-line has becn calcula ted by means of hofe r's method , accord in g to which the snow-line is fix ed as the arithm eti c mean between the averagc heigh t or the rid ge, limiting the glaciers acc umu lation area, and the lower height of the g lacie rs limit moraines (hofer, 1879). this mel hod is advisable ror short glacie rs, certain s lopes or ex pos it ions, so we speak about a local topographi c snow-linc. in the slud­ ied region two g lacial sou rce areas have been rix ed (smrekovac and radesevo), and the local topographic snow-line calculated ror each of them according (0 the aforementioned approach. ~ vcrticat temperature grad ient has been calculaled by means or [he known values o r the .tir temperature fo r fhe meteorologic;]1 stalions detnicc (69~ iii :lbo\'c sea-icvel) and li vi draga (935 m above sea-level), and it amount s [0 0.55°c ror every 100 m or elevat ion. uq i.jcoiogl<1 lro<ltl(;a :'lull height (m) 600 700 boo 900 1,000 1,100 1,200 1,300 1,400 1,500 1,52b today worm 7.65 -5.75 7.10 -6.30 6.55 -6.85 6.00 -7.40 5.45 4.90 4.35 3.80 3.25 2.70 2.55 -7.95 -8.50 -9.05 -9.60 -10.15 -10.70 -10.85 table 4 average annual ai r temperature of vcliki ri snjak (1,528 ill) today and in the pleistocene has been ca lculated by means of (he vertical temperature grad ient (o.55°c/i 00 ill). ii iii iv v vi vii viii ix x xi xii year delnice today 176.2 167.6 179.3 154.6 170.8 179.8 90.5 128.8 155.4 291.0 237.6 245.5 2,177.0 worm 123.3 117.3 125.5 108.2 119.6 125.9 63.4 90.2 108.8 203.7 166.3 171.8 1,524.0 lokve-dam today 176.8 140.0 160.3 156.3 145.3 173.1 68.5 120.0 195.9 279.5 250 .5 259.5 2,125.7 worm 123.7 98.0 112.2 108.4 101.7 121.2 48.0 84.0 137.1 195 .7 175.4 181.7 1,488.1 parg today 113.9 104.5 121.9 133.0 140.6 161.4 82.9 138.1 171.6 259.0 180.0 164.4 1,771.5 worm 79.7 73.2 85.3 93.1 98.4 113.0 58.0 96.7 120.1 181.3 126.0 115.1 1,239.9 uvidraga today 266.0 184.6 286.8 179.1 317.7 230.8 70.3 184.4 352.1 512.5 292.2 886.4 3,962.6 worm 186.2 129.2 200.8 125.4 222.4 161.6 49.2 129.1 246.5 358.8 204.5 620.5 2,634.2 risnjak today 3,358.2 wurm 2,350.7 table 5 average annual quantit ies of precipitation today (livid raga [981 1984: delnice, lokve-dam, parg 1981 1994: risnjak [963-1993) and reconstruction for the maximum of the wunn, meteorological classic rain-gauge rain-gauge with a net rain-gauge with a net station (today) (today) (reconstruction for the worm) delnice 2,177.0 5,420.7 3,794.5 lokve-dam 2,125.7 5,293.0 3,705.1 parg 1,771.5 4,411.0 3,087.7 lividraga 3,762.6 9,368.9 6,558.2 risnjak 3,358.2 8,361 .9 5,853.3 table 6 quantities of precipitation in the meteoro logical stations delnice, lokve-dam, parg and liv idraga , and on the riwjak summit measured by means of a classic rain-gauge, and reconstruction for measurments by means of a rain-gauge with a ne1 (today and in the wlirm). 4.1. the smrekovac area average height of the ridge: 1,349 m (northern mali risnjak 1,434 m veliki risnjak 1,528 m south­ ern mali risnjak 1,448 m janjicarski yrh 1,3 14 m vcliki bukoyac 1,266 m mali bukoyac 1,263 m hill 1,190 m) lower height of ihe glaciers limit moraine segine: 950 m local snow-lille: 1,150 m 4.2. the radesevo area (chiefly the area of croatian snjcinik) average height of the ridge: l ,4 12 m (lazacka glava 1,426 m croat ian snjeinik 1,50s m veliko radeseyo 1,363 m hilll,3s1 m cajtnik 1,416 m ­ veliki risnjak 1,528 m northern mali risnjak 1,434 m) lower height of ihe glaciers limit moraine lazac: 1,060 m, local snow-line: 1,236 m lower heighl of ihe glaciers limit moraine gasparac: 940 m bognar & i'rugovci::ki: glaciation traces in the area of thc risnjak moulllain massif local snow-line: 1,176 m in the studied area some glacial erosion and accu­ mulation forms, according to their location and exposi­ tion, suggcst the conclusion that they are not the result of the glaciers with the starting point in the area of the risnjak mountain massif, but their emergence is con­ nected with the work of the glaciers from sloven ian sneznik. as the research has so far been linked only to the risnjak mountain massif, the local topographic snow-line of the sneznik glaciers was taken from the work of sifrer (1959) dealing with the problems of the pleistocene glaciat ion on notranjski sneznik. 4.3. the slovenski sneznik area sllow~limil: 1.250~1.300 m (sifrer, 1959) the local snowlin es in the area of the risnjak mountain massif in the pleistocene were about 100-150 m lower than on the siovenian sneznik (accord ing to sifrer, 1959) and about 150 ~200 m lower than on velcbit (according to bognar ct ai., 1991 ). such a relatively lower snow-li ne can be explained by the northern exposure, relief protection and greater quantity of precipitation on risnjak. 5. recent snow-line on the basis of the prev iously defined pleistocene snow-line and vertical temperature gradient , (between the meteorological station in the valley and the one placed very high, as close to the pleistocene snow-line as possible), it is possible to calculate the recent snow­ line (the height above which conditions exist for glacial processes today). on the basis of observation, the snow-line of some glac iers in europe (messerli, 1967) has been defined, after that the average monthly temperature of the warmest month in the snow-linc area was calculatcd, as 4.soc. while calculat ing the average value, according to messcrli, a mistake from ±1.3 to ±1.4°c is possible, which corresponds to the height of +200 m of the snow-line. following the same principle the recent snow-line has been calculated for risnjak. the avcrage val ue of the snow-line in the risnjak arca in the pleistocene amounted to 1,190 m of the height above sea-level; the temperature of thc warmest month in li vidraga (935 m) was is.4°c, and by appli­ cation of the already known vertical temperature gradi­ ent of 0.s5°cjloo m, the temperature of the warmest month in the pleistocene snow-line area was calculated. it amounts to 14.0°c. the recent snow-line was calcu­ latcd by means of thc tcmpcrature fall of 0.55°c with every 100 m. today, in the risnjak area, it would be at the height of 2,890 m (then the tempcrature of the wannest month in the snow-line area amounts to 4.65°c what corresponds to messerli's method). as thc risnjak mass if is far below that height, only periglacial erosion is possible in that area today. 2j7 6. conclusion new study in the area of the croatian dinaridcs dis­ covered a series of traces of pleistocene glaciation on many mountain rangcs and massi fs. the risnjak moun­ tain massif and the croatian snjeznik mountain range arc two of them. by means of morphomctric analysis, reconstruction of the palaeoclimatic conditions, and fixing of the spa­ tial arrangement of the glacial rcl icf forms, wc can con­ clude that glaciation took place in the part of the ri s­ njak mountain massif above 1,150 m above sca-level, and in a part of the area of the croatian snjeznik moun­ tain range, then in a part of the obmc range, and that it was in spatial connection with the g laciers from the slovcnian sneznik. this suggests the fac t that the pleistocene glaciation of thc dinaric mountain systcm in croatia was far more wide-sprcad and prominent than was previously tho­ ught. therefore further research on all mountain massifs and rangcs above j ,3001 ,400 metres is necessary in ordcr to completc thc geoscienti fic and general natural­ scientific cognitions about the form, intensity and tem ­ poral duration of the glaciation in croatia. 7. literature bauer, b (1935): dber des nofdlichen velebit.­ l ahresber des bundesrealgymnasium in knittenfeld, 35~37. belij, s. ( 1985): glacijalni i periglacijalni reljef j uz ~ nog velebita (glacial and periglacial relief of sou­ thern vclebit).srpsko geografsko drustvo, posebna izdanja, 61, 1-68. bognar, a. (1975): osobine i regional no znacenjc banskog brda i juznc baranjskc lesnc zaravni.­ unpublished m.sc. thesis, university of zagreb, 206 p. bognar, a. & klein, v. (1976): litostratigrafski profil pleistocenih sedimenata grmoscice i njihovo znacenje u tumacenju geomorfoloskog razvoja me­ dvednicc.gcografski glasnik, 38, 30-51. bognar, a. (l987a): geolosko-stratigraiskc osobinc lugos lavijc .veliki geografski atlas jugoslavijc, sveui'iiisna naklada liber, 12-21. bognar, a. (l987b): tipovi feljda hrvatske.zbor­ nik 11 znanstvenog skupa geomorfologa lugoslavijc, 17-42. bognar, a., faivre, s. & pa velie, j. (1991): tragovi oledbe na sjevernom velebitu (glaciation traces on the northern velebit).geografski glas­ nik, 53, 27-39. cecura, z. (1995): geomorioloske znacajke central­ nog dijela dalmatinske zagore, zavale livanjskog i 278 glamockog polja s okolnim planinskim okvirom. ­ unpubli shed m.sc. thesis, univcrsity of zagrcb. 167 p. degen, a. (1936) : flora velebitiea (geogr. gliede­ rung, orografischc verhaltnissc; hydrogeographie).­ akademie der wissensehaften, budapest, 1-4, 7202. gavazzi, a. (1903): trag oiedbe na velebitu.glas­ nik hrvatskog naravnoslovnog drustva, 14,459. hofer, r. ( 1879): gletscher und eiszeitstudien.sitz. bee. d. ak. d. wiss. wien. rranilovic, h. (1901): geomorfoloski problemi iz hrvatskog krasa.gjasnik hrvatskog naravoslovnog drustva, 13/1-3, 93-133, zagreb. kaiser, k. (1961): klimazeugen des periglaziale dauerfrostboden in mittel und westeuropa.eis­ zeit alter und gegenwart, 11, 121-141. kirigin, b. (1967): klim atske karakteristike sjeve­ mag velebita. zbornik radova povodom proslave 20 godina rada i razvoja hidrometeoroloske sluibe jugoslavije 19471967, 189-206. klein, a. (1953): die niedersehlage in europa im maximum dec letzlcn eiszeit.peterm, geogr. mitl, 97, 165189. malez, m. (1965): 0 nekim periglaeijalnim pojavarna u pleis locenu siavonije (ubef e inige pcrigjaziajc erscheinungen in dem pleistozan slawoniens).­ geol. vjesnik, 18/1, 159-166. messerli, b. (1967): die eiszcitliche und die gegen­ wartige vergletscherung im mittelmerraum.geo­ graphica helvct iea, 3, 105-228. mihljevic, d. (1995): geomorfoloske znacajke gor­ skog hrpta ucke, gorske skupine cicarije i istarskog pobrda.unpublished phd thesis, university of zagreb, 377 p. milojevic, b.z. (1922): beleske 0 glecerskim trago­ virna na radusi, cincaru, salaru, troglavu i vcle­ bitu.glasnik srpskog geografskog drustva, 7-8, 294-297. nikler, l. (1973): nov prilog poznavanju oledbe ve­ lebita (ein neuer beitrag zur kenntnis der verei­ sung im velebit gebirge).geol. vjesnik, 25, 109112. geologia croa(ic<l son pecsi, m. (1961): die wichtigstein ergebnisse geo­ morphologischer forschungen des quarta.rs in un­ garn.inqua warszawa, wydaw. geologiczne, 287-311, warszawa. poljak, j. (1947): 0 zaledenju velebita (sur la glaci­ ation de la montagne de velebit en croatie).geo!. vjesnik, 1, 125-148. poser, h. ( 1947): austauftiefe und frostzerrung in boden mitteleuropas warend der wtirmeiseit.die naturwiessensehaft, 34. ridanovic, j. (1962): problem odredivanja snjoine granice.zbomik vi kongresa geografa jugos lavije, 249-256, ljubljana. ridanovic, j. (1966): orjen trajnost kraskog pro­ cesa i njegove modifikacije (orjen a contribution to the knowledge of the relief of littoral karst moun­ tains). radovi geografskog inst ituta sveucilista u zagrebu, 5, 5-103, zagreb. roglc, v. (1957): velebitska primorska padina (le versant littoral de velebit).geografski glasnik, 19, 61 -102, zagreb. sa vic, d. & dozet, s (1984): osnovna geoloska karta 1: 100000. tumac za li st de lnice l 33-90 (geology of the delniee sheet). geoloski zavod zagreb oour za geol. paleon!. i geol. zavod lju­ bljana, savezni geol. zavod beograd, 66 p. schubert, r. (1909): zur geologic des osterre­ ichisschen velebit (nebst paliiontologischen anh­ ang).lahrb. geol. reishsans!., 58/2, 335-386. sokac, b., barun, s. & velic l. (1976): osnovna geoloska karta 1:100.000. tumac za list otocac k 33-115 (geology of the otocac sheet).institut za geoioska istrazivanja zagreb, savezni geo!oski zavod beograd, 44 p. sifrer, m. (1959): obseg pleistocenske poledenitve na notranjskem snezniku (the extent of the pleis­ tocene glaciation on sncznik, in inner slovenia).­ geografski zbornik, 5, 28-81, zagreb. zeremski, m. (1977): kriogeni proeesi pleistocene periglacijalne klirne.zbornik radova geografskog instituta "j. cvijic", 29, 69-80, beograd. manuscript received apri l 14, 1997. revised manuscript accepted november 10, 1997. editorial-2-09.indd 73 �edi to rial i am pleased to inform our readers that geologia croatica has been selected for coverage in thomson reuters science citation index expanded (also known as scisearch or web of science – wos) and journal citation reports/science edition beginning on january 1, 2009! it is the best gift to our publisher, the croatian geological survey on their 100th anniversary. the croatian geological survey was founded on july 3, 1909 by the famous croatian geologist, dr. dragutin gor janović-kramberger under the name geological commission for the kingdoms of croatia and slavonia. the task of the commission was to study the‘montanegeological’ and ‘agrogeological’ aspects of croatia and slavonia through geological and ‘agrogeological’ mapping, and production of geological maps with explanatory notes. during the last hundred years since its inception the croatian geological survey has survived all the turbulent changes of passing times and events. the survey has an outstanding publishing record, and the inclusion of geologia croatica in the web of science is defi nitely one of the most important moments. the editorial board and the editor would like to thank once again the former editor dr. ivo velić for his long leadership of the journal and all the effort to keep geologia croatica alive. he served as the editor-in-chief from 1991 to 2008. along with prof. igor vlahović he is, without any doubt, the most important person that helped improve geologia croatica to be as good and timely as it is now. both of them were the spiritus movens that led to the present coverage of geologia croatica in web of science. our main task now is to maintain and further improve the quality of the journal. the steady increase of incoming manuscripts, online submission and handling of manuscripts through the open journal system will signifi cantly help. the members of the new editorial board, including both ivo velić and igor vlahović, accepted serving as associate editors specifi cally assigned to particular submitted manuscripts. their role is to search for appropriate reviewers, as well as to correspond with those reviewers and authors when considering the scientifi c content, arguments and presentation of manuscripts. it is a growing problem in all scientifi c journals to fi nd knowledgeable scientists who are willing to provide high quality reviews in a reasonable time, thus helping to improve the scientifi c level of papers and the entire journal. we look forward to receiving good quality manuscripts covering all aspects of the geosciences, but especially the geology of the dinarides, the adriatic/mediterranean region, pannonian basin, and/or karst issues, and we will do our best to even improve their level by our common effort. in order to maintain and further improve the journal quality we would like to stress again the importance of our language reviewer, dr. julie robson, whose continuous efforts have signifi cantly contributed to the language quality of the journal, especially since most authors are not english native speakers. it is our pleasure to announce that dr. marija horvat was appointed as a technical editor, and her skills and careful work will also improve the quality of our product. moreover, as you can see, our journal joined the ever growing number of journals that introduced doi (digital object identifi er) and joined crossrref. so, when you decide to submit your next manuscript to geologia croatica (and we hope that you will decide to do so soon), please go to our website:http://www.geologiacroatica.hr, read the instructions and prepare your manuscript accordingly, (it is also worth reading the editorial: why (and how) to publish in geologia croatica, vol. 61/1), and use our simple and easy open journal system to electronically submit the manuscript. we will help with the rest. mladen juračić, editor-in-chief the best present for the centennial anniversary of the croatian geological survey � doi: 10.4154/gc.2009.06 geologia croatica 62/2 73 zagreb 2009 geologia croaticageologia croatica geol. croa t. 51/2 175 193 21 figs. i i zagreb 1998 i nearshore deposits in the middle eocene clastic succession in northern dalmatia (dinarides, croatia) ljubomir babic' and jozica zupanic' key words: nearshore clastics, shoreface, beachface, delta, flysch, molasse, eocene, northern dalmatia, croatia. abstract the midd le eocene clastic sliccess ion in the radovin syncline is approximate ly 900 m thic k and consists of hemipelag ic and nysch­ type depos its in its lower part, and shallow-marine sediments in it s upper portio n. the upper portion embraces a unit of sandstones and conglomerates, which is represented by several facies. flatand low­ angle laminated. and hummocky cross-stratified sandstones (s 1) ori ­ ginated by storm-re lated processes in the sho re face. cross-bedded sandstones (s2 ) reflect longshore. offshore. and onshore nows also in shoreface settings. flat -laminated sandstones with planar truncation s (s3) refl ect swash processes. some sandstones possibly originated in the o ffshore transition zone. conglomeratesandstone co upl ets (cs) originmed by storm-induced flows in the shoreface. main conglome­ rates (cm) mostl y reflect various processes and modifications per­ formed in upper shore face and beachface sett ings of a refl ective coas t. most crossbedded conglomerat es (cx) reflect longshore flow s lind di ssi pative conditions. there arc also conglomerates which have poss ibly been deposited by gravity fl ows re lated to river floods. the shoreline was ori ented nw se. the architecture o f the sandstone-conglomerate unit is thought to res ult from the interfingering of deltas and nears hore sandy systems. deltas were of the shelftype, and were predominantly "wave-domi ­ nated". the sed iments studied reflect mo lasse-type deposition, which was induced by early postfl ysch changes in basin evolution and the palaeogeography of the palaeogene clastic basin in the coastal dina ­ rides . 1. introduction palaeogene clas tic depos its in the coastal dinarides overl ie mesozo ic to middle eocene platform carbo­ nates. [n northern da lmatia, these c lastics are 2.8 km th ick, and are represented by two large, superimposed units (rev iew in babic & zupanic, 1983; babic et ai. , 1995). the lower unit is some 900 m thick, and it s age corresponds to the middle-la te part of the middle eocene (schubert, 1905a; majcen & korolli fac ulty of science, univers ity of zagreb, institute of geology and palaeontology, kralja zvonimira 8, hrl 0000 zagreb, croatia. 2 facult y of sc ience, un iversity of zagre b, institute of mi neralogy and petrography, horvatovac bb, hrloooo zagreb. croatia. ja, 1970, 1973; muldini-mamuzic, 1972; iva­ nov ic et ai. , 1976). this unit comprises the sediments described here. the upper unit of the palaeogene clas· tics in northern dalmatia is represented by the 1900 m thick prom ina beds, which are late middle eocene to early oligocene in age (iv anovic et ai., 1976; sak­ ac et ai., 1993), and is not discussed here. thc lower clastics were the subject of different opin­ ions concerning their origin. above a basal deeper­ water marl , schubert (1905a, 1909; in schubert & waagen, 191 3) recognised sandstones, marls, and conglomerates of shall ow-marine and nearshore origin, which wou ld refl ect sea level oscillations. after marincic (1981), these clastics are recognised as ny­ sch sediments, wh ich are part of a long flysch belt strik­ ing a long the dinarides. other reports are concerned with two specific areas of northern dalmatia. in the zadar· radovin area (fig. 1), the lower clastics have been ca ll ed flys ch by muldini-mamuzic (1972), whi le majcen & korolija ( 1973) regarded these sediments as a molassc, which re fl ects the alternation of deep and shallowmarine cond itions. the same lowc r clastic un it exposed 10 the southeast in the benkovac area (fig. 1) , has been regarded by iv anovic et al. (1969) as fl ysch, and by ivanov ic et al. (1976) as deep· sea deposits. for sikic (1969), these sediments (above the basal marl) may be called " fl ysch-li ke deposits". the works on the lower clastic unit in northern dal­ matia mentioned above provide liltle evidence· in sup­ port of the various opinions. only the lower portion of these clastics from a restricted area (ra il way section in the benkovac area babic & zupanic, 1983) has bee n described in dctail. there is a need therefore to improve the knowledge of these sediments, which rep­ resent a record of the sedimentary and structural evolu­ tion of the dinaric chain after platform carbonate depo­ sition ceased. data presented here indicate that the low­ er unit of the palaeogene clastics in the radovin -zadar area, northern dalmatia, contains sediments which orig­ inated in nearshore environments, as already proposed by sc hubert (1905a, 1909). the interpreta ti on of these environments is supported by a description of the sed imentary features and relevant fac ies, whi ch have not been previously descr ibed either from the study area, or from elsewhere in the eocene of the coastal dinarides. 176 n a o g ~ ~ = l..:..:..:..:.. quaternary promi na reds ( e ofl.' iic 0 olil!orene) i .ower clas t ics (eocene) carboll alu (crcla~eous & palacogl'nc) e " e & ,. gl:ologia croa tica 5 1/2 , ~ ... . ... .. .. ... . .. i ' .. .. .. .. .. .. .. . . i ' .. .... ... .. .. .. . . . . . . . . . . . , , . i i . : : : : : : : : : : : : i ~ : :: : :: : : : : : ... .... . . . . . . . . . . . .. . . ~ .. .... . .. .... . .. . ... . . . . . . . . . . . . . .:: : : : .. .... . ,.8 .,., . benkovac . ri g. 1 ( jc:o lo!! ica l sw ing o f th e radtl vin synclin e . w hi ch ~ l rik~~ bc lwcc tl citp ljll b l j all ~ t at ld is lam l.'11i nski. a nd co tnpri sc~ the scd in1cll h describeci herc. nc~ idc~ be ing covered by qual e rnary ~ed illl ejl i .'. ihc palaeogene lower c]; i ~ l ics arc large ly covt'red hy ll lld irrcren iialed ~oil. t he fra med area i:-. ~ hown in hg.~. (ico log ica l illap an cr \1 a jci~n e l al. ( 1970), and iva'lov 1c cl;11. ( 1973 ). :-. i rn plifi cd. the ex tent of q uatcrn;try sedimcnt s is partly aner schubert ( 1909) at ld sci-/uil ert & w aa g en ( 19 12) . 'i'wo in se rt s silow ille ovcrall s iltl :llion . 2. st udy area ai\d the situation of sedimei\ts studied the sed im e n ts s tudied occur in ihc rado v in syn­ cline. \vh ich is situated in l 11e northern p <lrl o r nonil l: rt1 j);till1<1 1i a (fig. i ). 111 th is are a , i<i \c m iddle eoce ne clas­ l ies lire underla in by crelaccolls and earl y palaeogenc lilllc~ t () nes . the th in bas~:ti po rt ion o r ihe <:iastic s ucces­ sion is represcil( ccl by deep-wil ler marl s (sch ui3e rt, 1903, 1905", 1909 sch cbert & w aage:-i . 19 13). a rter schubert (01'. ci l) " nel y1ajcen & k oro, l ila ( 1970, 1973), ihe ma in port ion or ihe clas tic sli c­ c e s si on con s is t s or siu lli s tones, m ar ls , an d minor coi1 g l()lllcratcs. field work d ala s ugges t a prel im inary s u bdi v is io n o f the 900 111 thick success io n into rollr info rm a l u ni h (fig . 2). t he third un it o f this subdivision con ~ i s lill g or sandsto ncs and cong lomcrates shows the rcaturcs des­ c ri bed here. t he occurrence of co ng lomerates makes this unit c1 i1l e rc !lt from hoth ihe underly ing ane! overly­ ing units which consi st o r sgnd stol1cs. n ulllerou s a nd variotl .') ly or iented fault s d issccl the area o r the radovin s yncl ine . and d i:-.t urb the scd imc n o i3abic & zupanil: : nearshore deposits in the middle eocene clastic success ion ... informal units sandstones 4 8001'~'~"~"~'~"~"~'~' ________________________ -r~ o..<:? ? ~.9.9 700 ... ..... ... .. 000000 . :: : •••• ........ ' .. : :. 600'.:-: ...... :. :: :: 500 400 300 200 ........... .... 100 -o m ..... ....... . ............. --sandstone-conglomerate 3 sandstones sandstones and mudstones ~ (bm;aimarf) "foraminiferal limestone" 2 1 fi g. 2 schematic log of the eocene clastics in the radovin syncline showing informal subdivision of {he sedimentary succession. the sandstone-conglomerate unit (3) is described here . the clastic succession is underlain by the eocene shallow-water carbonates ('"foraminiferal limestone"). tary succession (schubert. 1905b. 1909. 1910). but the importance of these faults is mostly obscured, due to extensive cover of palaeogenc clastics by quaternary deposits and soil. some of these faults have been shown on the geological map made by majcen et al. (1970). cape ljubljllllu .1 2· qo ·3 n a stojici ljubac i km 177 3. terminology the term "sandstone" is used here for sediments consisting of sand-s ized particles regardless of the pro­ portion of non-carbonate and carbonate particles. sand­ stones contai ning an important proportion of num­ mulites are called "numm ulitic sandstones". the term "nummulit ic conglomerate" is used here for those conglomerates containing an important pro­ portion of nummulites, and the term "nummulite con­ glomerate" for rarcly occurring sed iments consisting of packed nummulite tests. when discussing nearshore depositional envi ron­ ments of gravelly beach complexes. the geomorpholo­ gical terminology is adopted following suggestions by leithold & bourgeois (1984) and definitions of term s by massari & parea (1988). specifically, the term "beachface" is used for the zone of the beach [rom the highest berm to the landward boundary of the shoreface, and the term "lower beachface" for that part of the beachface, which develops below the intert idal zone. 4. general features of sediments studied lateral tracing of beds and bed packages, as well as the study of sed imen tary successions of the sandstone­ conglomerate unit, were difficult due to extensive cover and numerous faults. most observations were made on scattered, "good quality" outcrops showing small parts of the entire vertical succession , situated in different parts of the radovin syncline. some large exposures, such as those in the razanac-zadar road cut (fig. 3, section a), provided little adequate data on sedimenta­ ry structures and fabric. the thickness of the unit stu­ died is greater than 30 m, and smaller than 130 m, and is probably inpersislenllalerally (fig. 4). 8· • 9 10 • 11,12 ":;.'-'~-= a fig. 3 location of logged sections and outcrops. see also framed area in fig. i. 178 geologia croalica 5 1n is unit 4 -----unit 3 = 55 x "" 00 " --x? 11 0 50 50 ---x? legend ~ iqq q q. oi a unit 4 -----:.~ ?~ ?§ ie b unit 3 a conglomerate 100 ~ <t> b granule cgj, 40 . . .. . . 40 pebbly sdst, <t> nummulite cgl , sandstone "","", " --flat lamination ~ cross stratification ~ cross lamination hcs hummocky i fig'. 15, 1. =<t> cross stratification 00000 0 <t> plant remains ;, 0· · · · 0000 00 0 00 "'40 006(f~ "'75 j!) bored clasts 000 0 "" 0 " " 90 "'50 is " " " 0 0 00000 bioturbation 30 --x 00000 30 '" i figs. ii, 12 "" "0 " maximal clast hcs 00000 "'50 size ( .<!= 25 em) °0 " 0 0""0°,,1 0000 0 ~o -x fault """,,0""0°,, 00000 "'.0 "" 00 (> 0000 0 00000 --x 0000 c "" 0"" rto "00" " 0" 0 0" :"-' ... ""00"0",,",, --x ,,0000 ,," 0" " 0" 0 0 " " " 0" 00000 " 0 0 0 0 00000 80 " " ,,0 " 0 0000 "0" " " 00000 20 00 ,,0 0 20 " " "0 " 00000 "'50 00000 0000 0 0000 0 0 0 00 (1" ,,0 " ,,0000 "'40 1 ,,000 0 0 00 = "'45 fig. 17 00000 a a 0000 0 '" 50 =--x? 00000 000 00000 ---x? ---x? "" " " " ~,o 00000 "'.0 55 " 000 0 " " 0 0 00 "0 0 000 0 0 00000 "'.0 00 00 0 70 ~o~o~o~o:o 0" 00 0 10 0" 0 0 " 10 \ 00000 x 0<>0 <> 0 -x? ° ° ° ° 00000 <i!.o 00 0 0 0 "'30 00000 ipso 000 ° <> a 00000 j!) "'40 0°0°0°0°0°1 00000 5 55 i ...... -55 00000 j!) o 0 " " 0 j!) '" 30 00000 "'25 o 0 " 0 ° 0000 ~~ 0000 fig. 5 j!) 00000 j!) ",'0 000 0 0 j!) "'25 unit 3 000 " 0 .0 hcs? unit 3 " 0 0 ° 0 0 0"" ° " <t> 0 , " 1 55 55 ~it2 m .. . ... unit 2 m @ ® fi g.4 simpl ifi ed logs a and b of (he sandstone-conglomerate unit 3. differences in thi ckness and facies in the two logs are partl y due 10 fault s. latcral changes are also due to differences in depositional setting as suggested by lat eral changes in some conglomerate packages local ly recognised at shorl di s tances. see tcxt for di scussion. nu mmu litcs may be common to abundant in 111 0st part s o f the success ion, and thcir occurrences arc no( indicated. note the dominancc o f sandstones not showing any structures due to weathering ("wemhered sandstones" in tex t). see fi g. 3 for location o f sections a and b. babic & zupanic: nearshore deposits in the middl e eocene clastic succession ... sandstones are fineto medium-grained, and locally coarse-grained. typical sandstones have 45% to 60% carbonate particles in composition, the rest being non­ carbonate particles, predominantly represented by qua­ rtz and chert. carbonate particles include skeletal parti­ cles and limestone clasts. nummulites may be scattered in sands tones or be an important component of sand­ stones ("nummulit ic sandstones"). conglomerates consist of clasts of limestones, sand­ stones, subordinate chert, and sand matrix. limestone clasts are partly palaeogene in age, including those with alveolina, nummulites, and those containing miliolids, and some clasts were derived from the late cretaceous succession. clasts of eocene sandstones vary in compo­ sit ion from dominantly non -carbonate to dominantly carbonate varieties, and both types may contain num­ mulitcs. in the finer-grained conglomerates, nummulite tes ts may be important constituent particles ("nummu­ litic conglomerate"), or may rarely be the highly pre­ dominant to excl usive particle type ("nummuli te con­ glomerate") . in coarser-grained conglomerates, num­ mulites are common in the sandy matrix. rare con­ glomerate beds contain a high proportion of bivalves, gastropods, and other marine macrofossils. 5. underlying and overlying sediments the following description and interpretation refer to approximately 10 m thick sequences, which appear just below and above the sandstone-conglomerate unit , and belong to the underlying and overlying sandstone units (units 2 and 4 in fig. 2) respectively. field data suggest that transitions between these sediments and the sand­ stone-conglomerate unit are gradual (figs. 4 & 5). description the underlying sediments are sandstones, which are most ly massive, and may contain nummulites, echino­ derms, pelecypods, and plant detritus. their massive appearance is a consequence of thorough bioturbation. locally, the sandstones display horizontal laminae, which may be marked by nummulites and other skeletal particles. sediments overlying the sandstone-conglomerate unit are dominant ly massive, bioturbated sandstones with subordinate horizontally laminated sandstones locally containing nummulites and plant detritus. illferpretation thorough bioturbation combined with occasionally preserved lam inat ions reflects alternating periods of high-energy sand deposition and bioturbation. as a gre­ ater part of the physical structures have been destroyed, the depositional rate was generally slower than the rate of homogenisation by bioturbation. such condit ions correspond either to the offshore transition zone, or to the lower shoreface, in both of which sand layers depo179 sited by storm-induced flows can be partly or strongly homogenised by organisms (ghibaudo et al., 1974; howard & reineck, 1981; howard & scott, 1983; dupre, 1984). thus, the deposition of the sandstone-conglomerate unit was both preceded and followed by deposition of sands in shallow-marine environments. 6. sediments of the sandstone­ -conglomerate unit the sedimentary facies encountered may be gro­ uped into sandstone facies and conglomerate-dominated facies. 6.1. sandstone facies description sandstones form both individual beds and packages up to 12.5 m thick, which alternate with conglomerates (fig. 4). the most common facies recognised are flat­ and low-angle-laminated, and hummocky cross-strat i­ fied (hcs) sandstones (s i). other types are cross-bed­ ded sandstones (s2) and flatlaminated sandstones with planar truncations (s3). it is to be noted that most sand­ stones encountered in the radovin syncline are strong­ ly weathered, and their structures are obscured (see also fig. 4). (si) flatand low-angle-laminated, and hcs sandstones. the lower contact of the beds is erosional, they may be rich in plant detritus, and are represented by several bed types and the transitions between them. one of the bed types (sla) (figs. 6 & 7) shows a relief on the basal surface of less than several centime­ tres. beds are 0.05 to 0.8 m thick, mostly show flat laminae, and locally, low-angle inclined laminae. sand­ stones locally contain scattered nummulites, which may be imbricated, and more nummulites and/or rare scat­ tered granules and pebbles may occur at the base of some beds. some of these beds are capped by a ripple cross-laminated interval several centimetres. thick. another bed variety (s i b) is 0.4 1.2 m thick, and shows basal scouring up to 0.2 m deep. the basal por­ tion of the bed, which is up to 0. 15 m thick, is com­ posed of either pebble to granule conglomerate, num­ mulitic conglomerate, or well-sorted nummulite con­ glomerate. this basal layer may vary in thickness and particle type composition laterally, and even pinch out or form wide lenses. the basal layer is sharply overlain by, or grades upwards into sandstone, which may show either flat lamination (fig. 8), low-angle inclined lami­ nae , or, in places, hcs. this sandstone may contain nummulites commonly aligned along the lamination. flat and low-angle lamination may include thick lami­ nae and several centimetre thick intercalations of num­ mulite conglomerate or nummu litic sandstone. num­ mulite tests may be imbricated. beds are rarely capped by thin ripple cross-lamination. 180 geologia croalica sin specific features lfaciesi code) proposed interpretation 1 low angle truncations erosion ----erosion pebbles to boulders discoidal clasts locally dominate bored clasts imbrication sw amalgamated beds 83 swash/foreshore ~~ swash/ foreshore? s2 "oo"r", si stonn b,d/ upp" ,oo"r", e. ~ b'"l upp., (?) ,bo"r", si sto,m 1 si sto,m 1 em uppermost shoreface ----erosion -----t---\-------------i cm~ uppermost shoreface pebbles to boulders discoidal clasts dominate bored clasts em uppermost shoreface imbrication sw ----erosion flat & low angle lamination (lies 1) capped by ripple x-lam. laminated & bioturbated sandstones si si si s2 si si si legend flat lamination cross stratification ripple cross lamination strong bioturbation sto<m b,d/ storm bed/ shoreface sto,m b,d/ storm bed/ shoreface sto,m bod, storm bed/ shoreface lower shoreface or offshore transition zone nummulites bioturbation bored clasts offshore transition zone sdst ---l i i l pebble to boulder cgl nuffimulitic ---.j l nummulite cgl sdst progradation of sandy nearshore ( i. shoreface to foreshore) i flood;ng i i ,u,r", i delta front/ coast (sbort -lived distributary mouth) progradation i'" i~ babic & zup,mic: nearshore deposit" in the middle eocene clastic sua:e.<;s ion ... fig. 6 sundstone bed showin g fiat lamination and pa rtl y vi sibl e small -sca le c ross-laminati on in ils uppermos t porti on. vi sible thic kness is 0.35 m. the base of the bed is not seen. an ophio1/l00pha burrow cuts the enti re bed (parallel to the pencil). loca­ lity 5 in fig. 3. severa l sandstone beds (s ic) show either hcs , a lateral trans it ion from fl at or low-angle laminati on to hcs , or a transit ion from hcs to cross-bedded sand­ stone. the basal portions of these beds may cont ai n more nummu lites or scattered pebbles. in most s i beds bioturbation is ei ther absent or rep­ resented by rare individual , mostly vertical ophiomor­ plio burrows and other shaft s (figs. 6 & 8). in some beds, the lamination may be disturbed by dispersed ver­ tical (hi ghly predominant) , diagonal , and hori zo nta l ophiomorpha burrows, and by v -shaped escape bu r­ rows tapering downward, and being marked by down­ warping lamination. burrows may be marked by num­ mulites , and some burrows show tubes armoured with nummulit e tests. rare beds show more intense biotur­ bation with some 20 -60 % of the lamination obliterated (e.g. fig. 7). (82) cross-bedded sandstones (fig. 10) are mostly represented by soutaly sets, and occasionally by two to three superimposed sets. individual sets are 0.05 to 0.1 8 m thick, and may contain scatte red nu mmul ites . beds may show an erosional base up to 5 cm in relief, and nummu lites concentrated at the base, as well as a basal layer (severa l centimetres thick) of nummulite con­ glomerate or nummulitic sandstone. some cross-beds show prcserved bri nk point s and topset laminae (fig. 9). occasionall y, cross-beds conti nue laterall y int o hcs , or fofm comp lex structures including hcs and cross-beds (fig. 9). severalmcasurements reveal eand nw-directed migrations of bedfonns. furt hermore, very rough esti 181 fig. 7 three superimposed sandsto ne beds inferred to re present storm depos it s in the shorefacc_ the lower one overlies a con­ glomerate bed. and shows only relict flat taminae due to biotur­ balion (oplliolllorp ha). the interm ediate bed is sharpl y based and shows nummulitc conglomerate at the base, and nummulites marki ng some laminae. the lam inati on is very gentl y inclined to the left. nummulite tes ls fi ll bu rrow s in the underlying sand­ stone. the base of the upper bed truncates the tamination of the underlyi ng bed. basal num mulite conglomerate of the upper bed contai ns rare pebbles . the fo ll owing fl at laminated sa ndstone contain rare nummulites. the key is 6.7 cm long. locali ty 10 in fig. 3. mates provide approximate direclions towards nw, se, s, and e. (83) f lat-laminated sandstones with planar trun­ cations (fig. 5). these sandstones are characterised by even lam inac and gently incl ined, planar erosional sur­ faces separating sequences of laminae. lam inae sequ ­ ences may sli ghtly differ in attitude, usually by less than 10' . interpretation deposit ion of all variet ies of (81) flatand low­ angle-laminated, and hc8 sandstones was preceded by erosion induced by high-energy turbulent fl ows. gravel-sized clasts (including nummulites) deposited at the base and followed by sand, refl ect decreasing ener­ gy condi tions during sto rms. occasional hcs suggests storm -related depositional processes, and the various associations of hcs, low-angle lamination, flat lamina' tion and cross-bedding suggest a storm-induced orig in of such associations, and the same may be true for these structures when found ind iv idually. low-angle inclined laminations could represent part of larger-sca le hcs structures, and may also be regarded as a form of hcs (nottvedt & kreisa , 1987; winn , 199 1). lateral transit ions from fl at laminae to hcs observed in the fi g. 5 dctail ed log showing speci fi c features and proposed interprctati ons for the uppermost portion of the sandsl.one unit 2 and the lowermost part of the sandstone-conglomerate un it 3, which arc ex posed at locality 6 (fig. 3). for vertical positi on see log b in fig. 4. no te tran sitional conlact between unils 2 and 3, ,md the dominance of slonn-relmed s i fac ies in sandy deposits. fig. 8 1-"1;11 laminatcd sandsto llc bed showing a 0 .1 mlhi ck ba~a l coil ­ glomerate layer. which consists of pebbles. nummul ites (wh ite particles), and rare cobbles. one cobb le occurs rig ht. below the pencil. which is 13.5 em long. lowermost laminae con tain scat­ tered nummulites. the sandstone shows rare ophiolllorplw blll"­ rows in the upper left and left cent re. and a vert ical. escape bur­ row to the right. locality 9 in fig. 3. radovin syncline are known elsewhere in the sedi mcn­ ta ry record (e.g. dupre, 1984) suggest ing depositi on of both by stonn-related flows. this also means that nat laminated sandstones fou nd alone may have orig inated by thc sam c processes . in fact , combined flow s may produce either nat lamination or cross-bedding depend­ ing on the relationship between the velocities of unidi ­ rect iona l and osc illat ory com ponents of the fl ows (myrow & southard, 1991 ). basal scouring must have been related to peak s[onn conditions and probably resulted from [he ac tion of sto rminduced rip current s. these eros ional surfaces and related beds consist ing of thi n basa l g rave l and overl ying sand, may be compared to sim ilar beds in the superb ly exposed pleistocene beach-s horeface com­ plexes, in fe rred to represent a record of the alongshore migration of rip channels and associated low-re lief bars (massar] & parea, 1988). similar sediments have also been descr ibed by dupr e ( 1984), who re lated them to storm condi ti ons in the upper shore face o r a barred nearshore. gravel-s ized skeletal particles, wh ich arc the com­ mon to exc lusive components of basal gravel, as well as [he icnsoid and sheet-like shapes of sueh gravel depo­ sit s, are well -known features of storm beds, ranging geologia cro:liic:l 51/2 fi g. y low-angle laminated (probabte i [cs) sandstone bed in the lower part shows repe.tted small-scale scouring and filling at its top right. it is overlain by low-angle to high-angle cross-bedded sandstone with preserved topsets. the upper part of the oli tcrop consists of [ow-ang le and nat lami nated sandstone. sandstones contain coarse pan icles (mostly nu mmulites) locally concentrated in lami nae and lenses. an opitiolllolpha shaft is seen in the cell­ ire. and less di stinct vertical (escape?) burrows also occur. lens cap is 5.8 em in diameter. locality 9 in fig. 3. fi g. [0 two superimposed cross-bedded sand stone sets overl ying a conglomerate bed (hardly recognisable in the picture), and under­ lying. rl atlaminated sa nd stone bed. penci l is 13.5 cm long. locality 5 in fig. 3. from siliciclastic to carbonate in composi ti on (kumar & sanders , 1976; kre1sa, 198 1; s hort, 1984; hobda y & morton, 1984). the rippl elaminated upper portion of some beds resul ted from small-sca le unidirectional or osci lla[ ory flows, induced eit her by the final affects of [he waning storm , by minor storms, or poss ibly, by fair-weather processes. highl y predominant ve rti ca l, deep op/tiomorp/ta shafts in sl sandstones reflcct the abilit y of this rele­ vant suspension feeder to use the shortest time interval compared to other burrowers [0 settle, burrow and con­ struct tube walls, before the nex t erosiona l and deposi­ tional evenls occurred (frey et ai. , 1978; pember­ ton et ai. , 1992). this indi cates a high freq uency of erosional/depositional events, i.e, frequent storms and a high deposition rate. such conditions are also indicated by escape burrows. babic & zup;lnic: near).horc dcl)()~ils in lhe middle eocene ci;islic succes.~ i on ... part of the sandstone beds of this facies (s i ) may be cons idered to represent the depositional record o f a storm -dominated upper shoreface. the uppcr shoreface setting is deduced from the combination of their verti­ cal s ituation closely below fores hore sand stones (s3 ; fig. 5), perfectly preserved and intact primary phys ical struct ures (bi ot urbation alm ost absent) , and the lack of mudstone int erbed s or drapes . anot her part of the s i sand stones lacks a c lose association with fores hore sandstones (s3; fig. 5), inc ludes both wel l-preserved physical structures and partially bioturbated beds, also lacks mudstone int erbeds, and re fl ects less frequent depos itional and erosional event s compared to the upper shoreface storm beds mentioned above. these sandstones may represent the depositional record of the lower shoreface . most g ravel -based sandstones (s i b) belong to th is group, and they resemble sandstone beds interpretcd by massar i & parea (1988) as lowcr shorefacc deposi ts. (52) cross-bedded sandstones. alth ough duncs (megaripples) may be produced by fair-weat her cur­ rents in recen t shoreface env ironmen ts (cl ifton et ai., 197 1), 1110st (if not all) cross-bcds in the radovin exampl cs probably originated during higher-than-"nor­ ma l" energy cond itions, i. e. by sto rm -indu ced flows. nw, se, and s di recti ons of bedform migra tion cou ld suggest probable longshore and offshore current s. these current s could result from storm -re lated fl ows along shore-parall el troughs associated with a bar and rip channel morphology (davidson-arnott & green wood , 1974; dupre, 1984). this is cons is­ tent within the depos itional context of the radovin clas­ tics, i.e. with overall domination of storm beds in sandy depos it s. preserved brink po ints and topsets, which indicate sand-rich nows, fit storm conditi ons well. tho­ se cross-bcds, which probably reflecl onshore (e) trans­ port , may relleet either onshore-directed dune migration during fai r-weather periods (clifton ct ai. , 1971 ) and recovery , or onshore-directed bar migrat ion du ring storlll s (davidson-arnott & greenwood , 1974; dupre, 1984). ri p-current s were probably responsible for the basal scouring in some beds. the occasional close assoc iation of cross-beds and i-ics represcn ts a feature known for a long time (don' & bo urgeois, 1982), which suggests a va riation of the importance of unidirec tiona l and oscillatory com po­ nents in storm -induced combined flows (myrow & southard, 199 1). crossbedded sandstones commonl y orig inate by dune (mega rippl e) migration in the upper shoreface (reading & collinson , 1996). ho wevcr, apa rt fro m tide-domi nated selt ings , dunes have also been obse rved farth er offshore and have been considered to have becn ac tive in ancient lower sho reface and shelf se ttin gs (s hort , 1984; revicws in walker & pll nt, 1992; johnson & baldwin, 1996) . thcse c rossbeds, whi ch alternate wi th well -preserved sto rm sancistone beds and arc verticnll y situated closely below 183 sandstones inferred to record an ancient foreshore (s3), probably originated in the upper shoreface. other eross­ bedded sandstones have probably been deposited some­ what lower in the shore face, as they are inte rcalated between storm sandstone beds inferred to reflect such an ellvironment (see above). (53) flat laminated sandstones with planar trun­ cations refl ect deposition by swash processes , and interm ittent eros ion and/or other changes in shore line conditions, after which the attitude of subsequent lami­ nae may change (cllfton, 1969; reineck & sin­ gi-i, 1980). some of the weat.hered sa ndstones the structures o f which arc obscured , ancl which are common in the radovin syncl ine (fig. 4), might represent nearshore deposits basecl on close association with sandstone and conglomerate fac ies inferred to represent nearshore deposits. other weathered sandstones may have origi­ nated in the offshore transition zone. 6.2 . cong lomerate-dominated facies conglomerate-dominated facies include (cs) con­ g lomeratc-sandstone couplets, (cm ) main conglomer­ ates cmbraci ng several facies variet ies, (ex) cross ­ bcdded conglomerates and sandstones, and "other con­ glomerates". (c5) conglomerate-sandstone couplets d escriplioll (figs. ii & 12). an erosional base up to 0.1 m in relief, is overlain by up to 0.4 m or pol ymodal to moderatcly soj1ed peb­ ble to granule (rarely to cobble) conglomerate, contain­ ing nummu lites and sandy matrix. thi s conglomerate may be overlain either directly by a sftndstonc division, or there may be an int crmedi ate, graded, pebbly-nulll­ mulitie conglomerate to granu le sandstone up to 0.1 m th ic k, which illay show hori zon tal stratifi ca tion. the sandy d ivision is up to i iii thick, ancl its primary thick­ lless has commonly been red uced by subseq uent ero­ s ion. thi s sandstone sho ws eithe r fl at laminae, low­ angle inc lined lam inae , or i-i cs, occas ionally marked by scattered ilummulites, and may be rich in plant det ri ­ tus including leaves. interpretafion vigorous erosion of underlying sediments preceded the emplacement of g ravel during hi gh-e nergy cond i­ tions, which were follo wed by the lowering of energy related to the gradi ng and deposi tion of sand. structures in the sand stones suggest storm -relatcd fl ows were responsible fo r the origi n of entire couplets in a manner discussed above for the conglomeratic s i sa ndstones. beds arc otherwise comparable to erosionall y based , up to 0.5 iii thick gravel overlain by laminated sand des­ cribed from the modern shore face and from ancient successions by kumar & sanders (1 976). accord­ ing to these authors, eros ion and depos ition or a gravel 184 4 flat & low angle inclined lamination nude flat lamination 3 ~oo ~ erosion ~----t---1 lies .... . 2 ~ erosion ~----t---1 ":' . .' .' 1 m sandstone, ~ i pebble cg\ -.j large nummulltes fig. ! 1 main features of several, superimposed conglomerate-sand­ stone couplets (sc) (1 to 4) inferred to reflect storm-i nduced processes in the shoreface. besides large nummulites indicated in ihe log, lhe cong lomerates contain smaller nummulites in sandy malrix. for exp lanation sec lext. sec also fig. 12. localily ii in fig. 3. verlical position in log a, fig. 4. lag occurred in the shoreface, by strong, storm-induced !lows, and the overlying sand was deposited during the waning stage of the same storm event. dupre (1984) has also disclissed a storm-related origin of similar gravel/sand couplets deposited in the upper shoreface. (em) main conglomerates description the above title embraces several facies, and inclu­ des combinations of superimposed conglomerate beds, which differ from one another mainly in clast size and shape. trans it ional sediment types from fine-grai ned conglomerates to sandstones may also be associated as well as rare coarse sandstones. outcrops being of limitm a i n features 1.5 i&'oc)0~ , ~oo~q equant clasts , , pi a9q,~ dominatc , indistinct , i , stratification ~oooooo() , gbo~~ , og 0 0 equant clasts , 0'2£ 00 ~-----------1\'0 oq'}cb dominate 0.5 9~3;tt/bo8a 0 t20d~ discoidal clasts dominate max. clast size = 40 cm /oo~t'?csf?a imbrication 45" 0 m pebble -.j : ~ . cobbte boujdcr geologia croalica 51/2 fig. [2 conglomerate-sandstone couplets (cs) shown by log in fig. ii. the sandstone below the hammer is erosiona lly overlain by conglomerate, which grades upwards into a finer-grai ned con­ glomerate with large nummulites (white, up to 3 cm in diameter). and then into hcs sandstone (2 in fig. 11 ). thi s sandstone is erosionally overlain by the next couplet (3 in fig. ii) consisting of conglomerate (poorly exposed, marked by 13.5 cm long pen­ cil), followed by granule conglomerate [0 nummu li te sandstone. and then by [ow-angle inclined (hcs?) sandstone. the upper part of the succession is represented by an erosiona ll y based con­ glomerate. hammer is 28 em long. locality ii in fig. 3. vertical position in log a. fig. 4. ed extens ion and usua lly show ing str ike-parallel sec­ tions, display parallel bedding the primary (deposition­ al) attitudes of which may have been either horizontal or gently inclined perpendicularly to their strike. con­ glomerates contain sand matr ix, and nummulites are present in most cases and may be abundant. examples of these conglomerate associations are described below. interpretation uppcr shorefacc or bcachface beachfacc or upper shoreface toe of bcachface fig. 13 main features and proposed interpretations for three super­ imposed conglomerate layers . for exp lanation see text. the matrix of conglomerates is nummulitic sandstone. imbrica­ tion of large di scoidal clasts in the lower layer dips towards ne (45'). locality 2 in fig. 3. babic & zupanic: nearshore deposits in ihc middle eocene clastic succession ... fig. 14 ·· imbricate-disc·' conglomerates of the beach face. bedding is gently incl ined to the ri ght. two adjacent beds show oppositely dipping imbrication, and the lower bed displays imbrication in oppos ite di recti ons occurring laterall y. the imbricati on is locally very sleep. note the sand malrix and we ll -so rt ed and ro unded clasts. lens cap is 5.8 cill in diameter. locali ty i in fig. 3. ( ia) the outcrop at locality 2 (fig. 13) shows a 1.5 m thick succession consisting of (a) cobble to boulder conglomerate with steep imbrication of large discoidal clas ts dipping towards the ne, (b) small -pebble con ­ glomerate with scattered large pebbles and small cob­ bles; equant clasts dominate, and (c) moderately sorted pebble to cobble conglomerate with dominant equant clasts. ( i b) el sewhere , coarse polymodal conglomerates show imbri cation of large clasts dipping toward s the specific features : : 185 sw. they may contain abundant nummuli tes, and some of them contain li lhophaga-bored cobbles and boulders (fig. 5). (2) a typical " imbricate-zone" (bluck, 1967) conglomerate success ion consists of superimposed 510 cm thick bcds of well-packed, imbricatcd, dominant­ ly discoidal pebbles (fig. 14). the imbrication in two superimposed beds , as well as in adjacent parts of the same bed may dip in opposite directions. ]n places, the imbricat ion may be very steep. the directions of imbri­ calion dips were 45 ' and 225' . clasts arc well-rounded and well-sorted, which apart from the imbricate struc­ ture, make these conglomerate beds outstanding com­ pared to most other conglomerates observed. the con­ glomerates contain sand matrix. (3) couplets consisti ng of a lower. coarse member and upper, fin e member (figs. 15 17) . the coarse me­ mber is represented by erosionall y based (relief up lo 0. 3 m) 0.15 to 0.5 m (or more) thick bimodal or poly­ modal conglomerate , which predominantly consists of pebbles and cobbles, and also contains scattered boul ­ ders, nummulites, granules ancl sand. thi s member may di splay indi st inct or c rude stratification wi th several layers showing different size distributions. in bimodal varieties modes are in the pebble/cobble and granule/ sand size classes. in some cases, the uppel1110sl portion of the lower member shows the gravel fram e infi lled by fi ner material identical to the sedimen t of the upper tentative _""lknu. swash lower beach face bimodal beach face or uppermost shoreface :c: ; rna<. ~ 0.27 m max. ifj 0.1 5 m ",' "' upper shoreface (rip . channel fill + bar ?) erosion ---swash lower beachface tq·~~~~'==----------------+---------beachface or uppermost shoreface i~~~ ~~~b~;mod'~i;;m~u.~[o~a'~mjt===~toc,~"~~~ i~~ )~ polymodal to moderately 15,s:j ""cd irl~~( indistin ct beddijlg upper shoreface fi g. 15 thc main fcat ures and ten­ tll tive interpretations of proces­ ses and se llings fo r the succes­ sion exposed at locality 12 (fi g. 3). for d isc uss ion and alt crna­ tive interpretations see text. ve­ rtical pos ition in log a, fig. 4. fig. 16 interval 0.3 1.7 in of (he log in fi g. 15. the po lymodal con­ glomerate at the base is ove rlain by bimodal sediment consisting of large clasts dispersed in granule conglomerate to granu le sand­ stone. this sed iment grades upwards into granu le sandstone showing nat laminat ion. the congl omerate in the upper part or the photograph (above the pencil , which is [3.5 cm long), is ero­ sionally based (scours seen lateral ly up to 0.4 m deep). for inter­ pretation see text and fi g. 15. locality 12 in fig. 3. vertica l posi­ tion in log a, fig. 4. membe r and di ffe ring from the matrix of the lower member (fig. 17). in olher cases, the lower member is capped by a discont inuous layer of bimodal conglome­ rate containing large clasts (cobbl es, bou lders), which may be dispcrsed in granul e conglomerate to granul e sandstone (fig. 15 0.5 -0.6 m). these clas ts arc the largest found in the sandstone-conglomerate unit , and may atta in 1.4 m in d iameter. the upper member is 0. 3 to i m thick, and cons ists of laminated pebbl y sand­ stone, granule conglomerate and/or granule sandstone, and coa rse sand stone , whi ch may contain discont inu­ ous, one-clast thick pebble layers, d ispersed pe bbl es and common nummulites (fig. 17). (4) disconlinuous tra ins of cobbles are intercalated in crudely strat ifi ed, poorly sorted , fi ne to coarse num­ muli tic pcbble conglomerates (fig. 18). i flfe/ ·prelalio!1 assoc iati ons of sediments diffcring in clast shape and/or size, si milar to those described above, common­ ly result from soj1ing processes on gravel beachcs sensl/ laro (b luck, 1967; orford, 1975; massa ri & gcologi:a cro:al ic:a 51/2 fi g. 17 the lower pari is represented by polymodal, pebbte-cobbte conglomerate. a boulder is partl y seen at the top o r thi s conglo ­ merat e, to the le rl. the cong lomerate is overlain by i"minated granule sandstone and cong lomerate contain ing trains or pebbles . the laminated unit is eros ionall y overlain by peb bl e to co bble conglomerat.e. all lithologies nre rich in nu mm ulites. lower and upper cong lomerates arc inrerred to repre sent the upper shore­ r,lce, and the laminated unit could represent a lower beachracc sett ing. for di scussion see tex t. hammer is 28 em tong. locality 7 in fi g. 3. vertical position in log b. fi g. 4. parea, 1988; postma & cruickshank, 1988; postm a & nemec, 1990) , but may also be genera­ ted in the upper shoreface (massari & parea, 1988). directions of im brication dips towards the ne and sw indicate a general nw-se strike of the ancienl shoreline. seaward directed c1inos tratificat ion usuall y characterising beach gravel complexes, may be prese l1l in the sediments studied, but could not be identified duc to the limilcd extension o r exposures , and the usual ori ­ entation of exposed sec ti ons parall el to the pal aeo­ shoreline. speci fi c features and conglomerate associat ions arc discllssed below. ( i a) coarse imbricated clasts in the lower layer (a) at locality 2 (fig. 13) might re neet a concentrati on of the largest avai lable clasts at the toe of the beach fa ce, where imbrication may dom inantly dip landwards (massa ri & parea, 1988) as in the case described here. they also resemble the " large-disc zone" (blu­ ck , 1967) i.c. the uppe r berm , or high sto rm berm grave l described by postm a & nemec ( 1990), but th is sell ing seems less probable as there is a domi nan t seaward imbrication. the middl e layer (b) resemb les bimodal conglomerates, whi ch may have orig inated by mixing and single-even t deposition in the upper shore­ face, or by two or more depos itional, eros ional, and/or reworking events in the beach race and upper shoreface sellings (massari & par ea , 1988). fin all y, the upper layer (c) dominaled by equant clasts and moder­ at e so rting cou ld be compared to ihe "infill zone" or bluck ( 1967) and postma & nemec (1990), i.e. 10 the beachface in genera l, and similar gravel may also be generated in the upper shoreface as prev ious ly d is­ cussed in relat ion to the middle layer (b). babic & zup:tlli~ : ncaf~hore deposi ts in the midd le eocene clastic succes~ ion ... fig. 1m train of cobbles intercollated in finer grained nummuliti c conglomerates. the cobbles are inferred to represent a lag depo~ it in the uppermost shoreface. hammer is 28 cm long. local it y 3 in fig. 3. (lb) coarse polymodal, nummulitic conglomerates showing seaward (s w) imbrication probabl y originated in the upper shoreface because of their mixed clast pop­ ulation and concentrat ion of marine foss ils (nummu ­ lites). although landward imbrication directions predo­ minate in this zone, seaward imbricat ion may also be produced (massari & parea, 1988). (2) " lmbricate-zone" conglomerates may be regard­ ed as the s ingle, best crite ri on for identifying a gravel beach in the fo ss il record (bourgeois & leit­ hold, 1984). among four shore-parallel zones identi ­ fied by bluck ( 1967) on a gravely coastline, the grav­ el consisting of imbricate discoida l pebbl es charac­ terised the " imbri cate zone", which formed in an upper pari of the beach face . opposite directions of imbrica­ tion dips, such as in the radovin examples, renect both landward and seaward traction processes, and back­ was h-induced s iev ing (bluck, 1967; massari & parea, 1988). based on a detailed study of excellent­ ly exposed sections of pleistocene beach complexes in ita ly , massari & parea (1988) found similar imb­ ricated gravels in bo th the inferred lower and upper beach face divi sion s. gravels assigned by these authors to the lower beach face were moderately well -sol1ed and steeply imbricated , usually landwards, wh ile those infe­ rred to have been deposited in the upper beach face sho­ wed better sorting, usual seaward or opposed (seaward and land ward) imbrication , and steep imbrication an­ g les are rare. the ex ampl es described here seem to more c lose ly resemble imbricate g ravel in the upper beach face of massari & parea ( 1988). imbricatc­ di sc facies in the holocene gravels of crete has been regarded as a mod erate wave-energy depos it of lower storm berm s (postma & nemec, 1990), which is consistent with the selling proposed above. (3) the eros ional contact at the base of the lower member resulted from strong nows, which removed some of the previous sediments, ancl wcre related to the peak of storms or to swells. the coarser fraction of the lowcr member may have been deposited by less vigor­ ous storm waves, and has been mixed with small er 187 clasts, resulling in a polymodal to bimodal size distribu­ tion (bluck , 1967; massari & parea, 1988). in the case of crudely/ind isti nctly s tratified conglome­ rates, individual layers could have been produced either by single resed imentation events mov ing beachface gravel into the shoreface, or by repeated reworking and mixing. thi s also explains the origin of the open frame­ work (into which fin er sediment was deposited during subsequent lower energy condit ions, either pass ively or by active mix ing) (fig. 17), and the concentrat ion of large clasts at the top of the coarse member (figs. 15 & 16). polymodal varieties of the lower mcmber containing coarse cobbles and bou lders (fig. 15: basal conglomer­ ates; fig. 17: lower and upper conglomerates), probably originated in the upper shoreface, and the concentration of large clasts capping the lower member may represent the toe of the beach face, and were possibly related to minor storm waves or long-period waves (massari & parea, 1988). these large c lasts may also be com­ pared to "storm lags" in the lowcr beachface of post­ ma & nemec (1990). part icles of the upper, fine member may have bcen re-mi xed wi th the underl y ing grave l, or infilled the gravel fram e, and these processes reflect lower-energy conditions. laminated sed im ent colltaning di spersed pebbles and discont.inuous, one-clast th ick pebble layers may have originated by the transport of gravel from the upper shoreface, or lower beach face into the swash zone, and also by partial reworking of berms or cusps, and mixing of different size populations within the swas h zone, during lower-energy conditions (mas ­ sari & parea, 1988). howe ver, stringers o f equant pebbl es may have resulted from the transport of such pebbles from the upper shoreface into the lower beach­ face by shoaling long-period waves (massar i & parea, j988). laminated sand of the uppermost part of the fine member could poss ibly have been produced by swash processes. conceming the sed iments shown in figs . 15 and 16 other interpretat ions should also be mentioned, one of these includes storm-related processes and deposition in the upper shoreface as discussed above related to (cs) conglom erate-sands tone co uplets. thi s origin see ms less probable for the orig in of the lower couplet because of the large clast size present, but may be poss ible in ' the case or th e upper two coupl ets. another poss ible origi n involves the depos ition of the coarse , lower mem ber by a non-cohes ive debris flow , and the fine member by turbulent flow, both relat ed to river flood. de ltafront sedim en ts of such orig in are kno wn from the geological record (e.g. kleinspej-in et ai., 1984), and [he presence of a marine fauna (nummulit es) can not exclude thi s interpretation. (4) di scontinuous train s of cobbl es wit hin nuill ­ ltiuliti c fin e to coarse pebbl e conglome rates (fig. 18) may be explained as lags, which resulted from rework­ ing in the uppermost shoreface during minor storm or 188 fig . 19 sci o f cross-bedded, finc-grained co nglomerates and granu le sandstones underlain by polymodal pebble to cobble conglome­ rate, and overlain ri rst by (hin horizontally laminated, granule to ilummulilic sandstone and sandstone, and then by cobble to boul­ der conglomerate of ihe probable upper shoreface . cross-beds atc inclined iowards the nw, and are interpreted as havi ng been deposited in a longshore trough following the peak of a storm. hammer is 28 em long. locality 4 in fig. 3. fig. 20 in the lower part of the photograph there is a horizontally s tratified grallljlc conglomerate (visible thi ckness=20 em) of probable bcachfacc/uppcrmost shoreface sett ing. the conglo ­ merate contains scattered pebbles in its lower part and a cobble in its upper portion. this conglomerate is overlain by cross~bedded conglomerate to granule sandstone (d ipp ing right) inferred to have originated by a longshore migrating bedform. locality 8 in fig . 3. swell condit ion s (sec massari & parea, 1988). this is consisten t with the probable upper shoreface setting of the associated nummulitic conglomerate. geologia croarica sij2 (cx) cross-bedded conglomerates description this facies (figs. 19 & 20) is represented by singu­ lar sets up to 0.4 m thick, which may show an erosional base and are erosionally truncated. cross-beds consist of granule to pebble conglomerates, granule sandstones, and sandstones. they are intercalated in pebble to boul­ der conglomerates, which may show imbricated clasts and probably represent upper shoreface deposits. sets are mostly planar, with tangential and angular lower contacts, and the inclinations range up to the angle of repose. nine out of a total of twelve measurements indicated nw, and se to e directions, two were to~ wards the ene, and one towards the s. interpretation the dominant directions of bedform migration lowards the nw and se renect longshore flows. these werc probably related to a shorelinc-parallel rhythmic topography and related dissipat ive conditions gencrated during storm s, and related longshore transport in tro­ ughs (d upre, 1984; letthold & bourgeois, 1984; massari & parea, 1988). longshore trans­ port of gravel has also been documented by hart & plint (1989). s-directed now (one measurement) may have been related to the end of the seaward-opened trough, or to the rip-channel fi ll. directions towards the ene (2 measuremcn ts) may represent either onshore bar or dune migration in the recovery stage (dupre, 1984), or a longshore dune migration in the case of a shoreline with an irregular profile. "other conglomerates" in some places (e.g. fig. 4, a, bctween 65 and 90 m), there arc conglomerates showing more than 0.5 m thick beds, which common ly contain boulder-sized clasts, and may contain nummulites. the matrix is sandy. thi s conglomerate type m;:ty have been deposit­ ed by debris flows at the distributary mouths. another conglomerate type shows overall g radcd , composite beds up to 1.3 m thick (e.g. fig. 4, a, at 52 111), and consists of pebble conglomerate in the lower part and flat laminated pebbly sandstone to sandstone in ihe upper part both conta ining nummulites. they are intercalated in "weathered sandstones", which may be deposjts of the nearshore or offshore transit ion sett ing (sec above). such beds could possibly represent slorm­ related, nearshorc deposits, or products of flood-related, gravity-flows. 7, the general character of nearshore settings recorded by the sandstone-conglomerate unit descriptions and interpretations presented above depict nearshore settings, which were of two lypes: onc was dominated by gravel, and the other by sand. l3abic & zupanic: ne:ltshore deposits in the middle eocene clastic succession ... n a flot in .w:llle , , , , , , , , ',j')~j <.j) ' -0')" '" , , , fig.21 conceptual piclute showing the palaeogeography and ide­ alised distribution of the dominant dcpos itional facies during deposition of the sandstone-conglomerate unit studied in the radovin syncline. facies codes as in tex t. codes in brackcts are subordinate components. for discussion see text. when ihc flu ­ via l system was tc mporarily not active. the mouth co uld have been barred by marine processes. a previous posi tion of the stre­ hill is also shown. the most common sed iments among the conglome­ rate-domi nated facies arc those included in the (cm) main conglomerates, wh ich are interpreted here as upper shoreface and beach race deposit s. the character­ istics of these facies resulted from processes related to minor storms , declini ngand post-storm periods, swell , and rair-weather conditions. these features describe the predominant reflective character of the coast during such condi tions. processes relat ed to the high stage or major storms were responsible fo r the origin of most erosional surfaces. high-stage to declining storm pcri ­ ods were probably responsib le fo r longshore-oriented flows and strong rip currents, which resulted in depos i­ tion of most (cx) cross-bedded conglomerates indi cat­ ing a bar and trough topography, i.e. the establ ish ment or dissipative conditions. the sto rm conditions were also respons ibl e for the orig in of (cs) conglomerate­ sandstone couplets. the o rigin of some conglomerates may be rela ted to gravity flows during river fl oods. conglomerates may be ri ch in boulderand cobble­ s ized c las ts, whi ch were unlikely to have been trans­ ported far along the coast. the gravel therefore, espe­ cially the boulder gravel, reflects the close proximity of the mouths of river distributaries , and also the mouths themselves. thus, the gravel-dominated beach face and shoreface may be rcgarded as the shoreline and shallow subaqucolls parts of coarse-grai ned fan-delta or braid­ delta complexes fed by high-gradient braided streams (fig. 21). as described above, coarse-gra ined delta sediments arc associated with shallow~marine sandstones, both within the sandstone-conglomerate unit, and wi thin the 189 overall success ion of the radovin syncli ne. therefore thi s delta is comparable to the shelf-type model of fan­ delt as differe ntiated by ethridge & wescott (1984), based on differences in basin margin gradients, or to the relevant braid de ltas later recogni sed by mcpherson et al. ( 1987). in respect to the dominant processes operating at the del ta front (nemec & steel, 1988; colella & prior, 1990) , a major pan of the eocene deltas in the radovi n syneline may be assigned to the "wave-dominated" type of fan-deltas or braid deltas, as the material brought by ancient rivers 10 the sea shore was reworked by marine processes. during some time intervals, some deltas may have been dominated by massfl ow deposits . the sandstone facies s i , s2, and s3 orig inated in the lower shoreface, upper shoreface, and foreshore set­ tings respect i vel y. i n shore fa ce se t! ings (facies s 1 and s2) of thc ancient radovi n area, erosion, deposi tion and the biogenic disturbance or sedim ent s were s trongly influenced by storm-induced processes. fair-weather processes including reworking during minor-storm peri ­ ods, and bi oturbation are scarcely recorded in these sed­ iments. the associations or various s i and s2 faci es described here may be compared to recent amalgama­ ted storm sa nd beds described by aigner & rei ­ neck (1982) from a storm-dominated sandy shore­ face . tn such settings, sedimentary structures, which cou ld have been produced by fair-weather processes, have mostly been obliterated by storm-related processes (kuma r & sanders, 1976; dupr e, 1984). the relevant ancient env ironment s therefore were charac­ terised by a high freq uency of storms and hi gh deposi­ tional rate. apart from gravel-dominated delta-fronts, there were pure sandy nearshore settings, which can be dedu­ ced from sa ndy progradati onal sequcnces such as the upper sandstone segment in fig. 5. such sandy settings could have been situated laterally to gravel-dominated dclta mollths, at distances g reatcr than those attainable by the wave-d ri vcn longshore d rift of gravel. 1t is also possible that there were intervals when only sand was deposi ted along the cntire nea rshore belt of the former radovin sy ncline area. a part of storm-related sand­ stones was probably deposited seawarcls of the gravel­ dominated river mollths (fig. 2 1), and these sandstones would represent d istal delta-front deposits. the deposi tional architecture of the sandstone-con­ glomcrate unit can be inferred from the facies analysis presented above taking into account ( i) the entire sand­ stone-conglomerate unit in the rad ovin syncline con­ sisting of altcrnating sandstones and conglomeratcs; (2) all sed iment s showing depositional structures and fabric reflect ing nearshore sett ings (these scd imcnts appear in sma ll , isolated outcrops and up to 10 in thick succes­ sions scallered th roughout the unit and withi n the whole radovin area, while larger cont inuous exposures, which would show vertica l s ll ccessions, lateral changes and facies relati onships, arc absent) (3) conglomeratic sed i­ ments and packages change their thickness latera ll y, 190 which implies a lateral change in thickness of the sand­ stones. based on these features the overall architecture may be described as interfingering and overlapping deltas and nearshore sandy systems. those sandstones, wh ich could have been deposited in the offshore transi­ tion zone, may be added to the above scenario. the architecture of the sandstone-conglomerate unit was generat ed by an interplay of external factors such as sediment supply, tectonics, and sea-leve l changes, and internal ractors including the lateral shifts of deltas or delta distributaries, and changes in fluvial input. details of the related trends of depositional dynamics are rarely clearly observed, the best example being shown in fig. 5, wherc an overall progradational succession ranging from offshore to foreshore settings includcs two small­ scale, sandy progradational sequences, and an interme­ diate gravel package. the top of the gravel package is a flooding surface reflecting a relative sea-level rise. 8. the sandstone-conglomerate unit and the evolution of the palaeogene clastic basin in northern dalmatia the evol ution of the palaeogene clastic basin in northern dalmatia began in the middle of the middle lutetian with the drowning of the previous carbonate platform, and deposition of hemipelagic marls over the platform carbonates (schubert, 1905a; review in babic & zupanic, 1983). these marls arc followed by flysch-type sediments (unit i, fig. 2). post-ilysch evolut ion is characterised by develop­ ment of shallow-marine environments in the previous flysch-basin domain, as revealed by shallow-marine charactcr of the overlying sandstones and subsequent depos it s (fig. 2). the sandstone-conglomerate unit described here (unit 3, fig. 2) includes coarse-grained delta front deposits, which must have been connected with high-gradient streams, and the dissected topogra­ phy of the source area situated in the vicinity of the coast. powerful transverse flows brought the detritus from land to the north-east to the nw-se oriented shoreline, and this palaeogeography corresponds to the "model 2" of typical alluvial basin-fill patterns sum­ marised by miall (1996). lithoclast types in the con­ glomerates reflect sediment supp ly from an emerged arca, where eocene and late cretaceous sediments were exposed, as already reported by quitzow (1941) and majcen & korolija (1973). the sup­ ply of coarse-grained detri tus may have been related to the middle eocene tectonic deformation, which was recognised by quitzow (1941). middle eocene shallow -water clastics may be regarded as molasse deposits, which postdate flysch­ lype deposits and predate the prom ina beds. thus, this molasse was generated very early in the evo lution of the north dalmatian palaeogene clastic basin. this is in confirmation of previous propositions on early changes in the palaeogeography of the coastal dinaric clastic geologia croalica 51(2 belt (babic & zupanic, 1990; zupanic & ba­ bic, 1991 ; babic et ai., 1993). 9. summary and conclusion the middle eocene clastic succession in the rado­ vin syncline, northern dalmatia is approximately 900 m thick and consists of basal hemipelagic marl and fly­ sch-type depos its in its lower part, and shallow-marine sediments in its upper part. identification of shallow­ marine depos its in the upper part of the successions confirms the view prescnted by schubert at the begin­ ning of this century (schubert, 1905a, 1909). within the upper, shallow-marine portion of the clastic success ion in the radovin syncline, there is a distinct strat igraphi c unit consisting of sandstones and conglomerates. the overall architecture of this unit may be described as the interfingeri ng of deltas and near­ shore sandy systems. the unit was generated under the influence of several internal and external factors, and the most important of these werc sediment supply and changes in relative sea leve l. deltas were of the shelf­ type, and were predominantly "wave-dominated". the sand and g ravel were transported by high-gradient st reams and possibly by grav ity flow s from emerged areas. final deposition mostly occurred within the near­ shore environments of a high-energy coast. most sand­ stones originatcd by storm -related processes in the shoreface. conglomerate-dominated facies mostly res­ ulted from variolls and successivc eros ional, depositio­ nal and reworking processes in thc shoreface and beachfacc sett ings. the sediments studied document important post-fly­ sch changes in [he basin evolution and palaeogeography of the palaeogene clastic basin in the coastal dinarides, and the earliest post-flysch emersion of an inner part of the basin. acknowledgement constructive criti cism by prof. francesco mas­ sari helped greatly in c larifying and presenting the facies interpretations. an anonymous reviewer suggest­ ed improvements in petrographic tenninology. we also thank m. kladnicki for careful drawings. the work has been supported by the ministry of sc ience and technology of the republic of croatia, through the project 119302. lo:references aigner, t. & reineck, h.-e. (1982): proximality trends in modern storm sands from the helegoland bight (nort h sea) and their implications for basin analysis.senekcnbergiana marit., 14, 183-215. babic, lj. & zupanic, j. (1983): paleogene clastic formations in northern dalmatia.in: babic, lj. & gabie & zupan;!:: near..hore dci>mits in the middle eocene ciri.~lic succc.~sion ... jelaska , v. (cds.): contributions to sedimento· logy or somc carbonate and clastic units of the coastal dinarides. 4th international association of sedimento log ists, regional meeting, split , excur­ sion guidc· book, 37-61, zagreb. babic, lj. & zupan ic, j. (1990): progradationa l sequences in the paleogene clastic basin of the out­ er dinarids, from northern dalmatia to western hercegovina (in croal., eng l. summary).· rad ju· gos l. akad., 449 (razr. prir. znan., 24), 319-343, zagreb. babic, lj. , zupanic, j. & crnjakovic, m. ( 1993): an associat ion of marine tractive and gravi­ ty flow sandy deposits in the eocene of the island of pag (outer dinarides, croatia).geologia croatica, 46/1,107-123. babic, lj., zupanic, j. & kurtanjek, d. (1995): sharply· topped alluvial gravel sheets in the palaeogene prom ina basin (dinaricles, croalia).­ gcologia croatica, 48/1, 33-48. bluck, bj. (1967): sedimentation of beach gravels: examples from south wales.· j. scdim. petrol., 37, 128-156. bourgeois, j. & leithold, e.l. (1984): wave· worked conglomerates depositional processes and criteria for recognilion.· in: koster , e.h. & ste· el, r.i. (cds.): sedimenlology of gravels and con· glomerates. mem. can. soc. petrol. geol., 10, 33 1343, calgary. clifton, h. e. ( 1969): beach lamination: nature and origin.· marine geol. , 7, 553-559. clifton, h. e., hunter, r.e. & phillips , r.l. (1971): depositional structures and processes in the non -barred , hi gh-energy nearshore.j. sedim. pet1'01. , 41 , 651-670. colella, a. & prior, d.b. (eds.) (1990): coarse· grai ned deltas.spec. pub!. intern. assoc. sedim., 10, blackwell , oxford, x+357 p. davidson·arnott, r.g.d. & greenwood, b. (1974): bedforms and structures associated with bar topography in the shallow-water wave environment, kouchibouguae bay, new brunswick, canada.j. sedim. pelrol. , 44, 698-704. dott, r.hjr & bourgeois, j. (1982): hummocky stratification: sign ificance of it s variabl e bedd ing sequences.· bull. geol. soc. am., 93, 663-680. dupre, w.r. ( 1984): reconstruction of palco· wave condit ions during the late pleistocene from marine terrace deposits, monterey bay, califomia. marine geol., 60, 435-454. ethridge, f.g. & wescott, w.a. (1984): tee· tonic sctting, recognition and hydrocarbon reservoir potenlial of ran·della deposits.· in: koster , e.·h. 191 & steel, r.j. (cds.): sedimentology of gravels and cong lomerates. can. soc. petrol. geo l. mem­ oir, 10,217-235. calgary. frey, r.w., howard, j.d. & prior, w.a. ( 1978): ophiomorpha: its morphologic, taxonomic, and en­ vironmental signi fi cance.palaeogeography, pal ­ aeoclimatology, pal aeoecology, 23, 199-229. ghibaudo, g., mutti, e & rosell, j. ( 1974): le sp iagge fossili delle arenarie di aren (cretacieo su peri ore) nella valle noguera-r iba-gorzana (pire­ nei centro-meridionali , province di lerida e i-iuesca, spagna).· mem. soc. geol. ital., 13 ,497-537. hart, b.s. & punt, a.g. (1989): gravelly shore· face deposits: a comparison of modern and anc ient facies sequences.· sedimentology, 36, 551-557. hobday, o.k. & morton, r.a. (1984): lower cretaceous shclf storm deposit s, northeast texas.­ in: tillman, r.w. & siemers, c.t. (cds.): sili· ciclastic shelf sediments. spec. pub i. soc. econ pal. miner. , 34, 205-213, tulsa. howard, j.d. & reineck, j. ·e. (1981 ): deposi· tional sequences of hi gh-energy beach-to-offshore sequence, comparison to low-energy sequence.­ bull. am. assoc. petrol. geol., 65, 807-830. howard, j.d. & scotf, r.m. (1983): compari son of pleistocene and holocene barrier island beach-to­ offshore sequences, georgia and northeast florida coasl, u.s.a.· sed. geology, 34, 167-183. iv anovic, a., muldin i· mamuzic, s., vrsa· lovic·carevic, i. & zupanic, j. (1969): dev· elopment of paleogene deposits in wider area of benkovac and drni s in the north-western part of dalmatia (i n croal. , engl. summary).· 3. simpozij dinarske asoeijaeije, i, 5 1-7 1, zagreb. iva nov ic, a., sakac, k. , markovic, s., so· kac, b. , susnjar, m., nikler, l. & sus· njara, a. (1973): osnovna geoloska karta sfrj i: 100.000. list obrovac l33i 40.· insl. geol. istraz. zagreb (1962-1967), savezni geol. zavod, beograd. iv anovic, a. , sakac, k. , sokac, b. , vrsa· lovic·carevic, i. & zupanic, j. ( 1976): osnovna geoloska kart a sfrj i: 100.000. tumac za li sl obrovae l33-140 (geology of the obrovac shee t). · ins!. geol. istraz. zagreb (1967), savezni geol. zavod, beograd, 61 p. joh nson, h.d. & baldwin, c.t. (1996): shal low c1aslic seas.· in: reading, h.g. (cd.): sedimcnta· ry environments: processes, facies and stratigra­ phy. 3rd ed., blackwell science, 232-280. klei nspehn, k.l., steel, r.j ., johannessen , e. & netland, a. ( 1984): conglomeratic fan· delta sequences, late carboniferous-early permian, wesiern spitsbergen.· in: koster, e.b. & steel, r.j. (eds.): sedimenlology or gravels and con · 192 glomcrates. canadian society of petroleum gcolo­ gists, memo ir, 10,279-294, calgary. kreisa, r.d. (1981): storm-generated sedimentary structures in subtidal marine fac ies with examples from the middle and upper ordov ician of south­ western vi rginia. j. sed im. petro l. , 51,823-848. kumar , n. & sanders, j.e. ( 1976): charactcristics of shoreface storm deposits: modern and ancient examples.j. sedim. pctrol., 46, 145-162. leithold, e. l. & bourgeois, j. (1984): charac­ teristics of coarse-grai ned sequences deposited in nearshore, wave-dominated environments exam­ ples from the m iocene or south-west oregon.sedi­ mentology, 31, 749-775 . majcen , z. & koro llja, b. (1970): un proj"i l inlcrcssant a travers les couches de ravni kotari el les iles de zadar (ugljan, ii, rava, dugi otok) (in croa!., french sl1 mmary).gcol. vjesnik, 23, 103112. majcen , z., korol ij a, b., sokac, b. & nik ­ ler, l. (l970): osnovna gco loska karta sfrj 1:100.000. list zadar l33139.ins!. geol. ist raz. zagreb (1969), savczni gcol. zavod, beograd. majcen, z. & korollja, b. ( 1973): osnovna geo­ loska kana sfrj i: 100.000. tumac za lis t zadar l33-139 (geology of the zadar shect).ins!. geol. isu·az. zagreb (1967) , savezni geo l. zavod , bco­ grad , 44 p. marincic, s. (1981): eocene nysch of adriat ic area (i n croat., eng!. summary).geol. vjcsnik, 34, 2738. massar i, f. & parea, g.c. (1988): progradat ional gravel beach sequcnccs in a moderale10 high-encr­ gy, microtidal environment.scd im entology, 35, 88 1-9 13. mcpherson, j.g., si-ianmugam , g. & miola, r.j. (1987): fan-deltas and braid deltas: varieties of coarse-grained dcltas.bull. geo l. soc. am ., 99, 331-340. miall, a. d. (1996): the geology of fluvial depo­ sits.springer verlag, berlin , xvi+582 p. muldini-mamuzic, s. (1972): ili ostratigraphy of paleogcnc bcds in ihe broader zadar area (in croal, engl. sllm mary).nana, 22, 195-207, zagreb. myrow, p.m. & southard, l b. (1991): com­ bined-flow model for ven ical stratifi cation sequ­ ences in shallow marin e storm-deposi ted beds. j. sedim. petrol., 61, 202-210. nemec, w. & steel, r.j. (1988): fan deltas: sed i­ mcntology and tecton ic sehings.blackie, glas­ gow, xvii+444 p. norrvedt, a. & kreisa, r.d. (1987): model for the combinednow origi n or hummocky cross-strati ­ fication.geology, 15,357-361. geologia croalica 5 1/2 orford, d.j . (1975): discrimination of part icle zona­ li on on a pebble beach.sed imentology , 22 ,44 1463. pemb erton, s.g., maceachern, j. a. & frey, r.w. ( 1992): trace foss il facies models: environ ­ mental and allost rati graphic signif'icance.in: wal­ ker , r.g. & jam es, n.p. (eds.) : faeies models, response to sea level change. geological associa­ tion of canada, s!. john 's, 47 -72. postma, g. & cruickshank, c. ( 1988): sedime­ ntology of a late weichselian to holocene terraced ran delta, varangerfjord, northern norway.in: ne­ mec , w. & steel, r.j . (cds.): fan deltas: sedi­ mentology and tectonic settings. blackic, glasgow, 144-157. postma, g. & nemec, w. (1990): regress ive and transgressive sequences in a raised holocene gravel­ ly beach, south western crete .sedimentology 37, 907-920. quitzow, 1-1. w. ( 1941): stratigraphiseh-tektonisehe untersuchungen im norddalmatin ischel1 al ttcrtiar.­ l ahrb. reiehs!. bodenforschung, 62, 422-437, wien. reading, h.g. & colli nson, j.d. ( 1996): clastie eoasts.in: readi ng, h.g. (ed .): sedimentary environments: processes, facies ancl stratigraphy. 3rd ed., blackwell seience, 154-231. reinec k, h.-e. & sing h, i.b. ( 1980): depos itional sedimentary environmems.2nel eel. , springer-ver­ lag, berli n, xix+549 p. sakac, k. , benic, j. , bahun, s. & pencinger, v. ( 1993): st ratigraphic and teetonie pos ition of paleogene jelar becls in the outer dinaricles.natu­ ra cromica, 2, 55 -72, zagreb. schubert, r.j. (1903): zlir geologic des kar1enbl at­ tbereiehes benkovae-novigrad (29, xiii). iii. das gebiet zw ischen polesnik, sm ilcic ancl posscdari a. ­ verhandlllngen geol. reichsan s!., 1903/14, 278288 , wien. schubert, r.j. ( 1905a): zlir stratigraphie des istr i­ sch-norddal mal i ni schen m itte leocans. j ahrbuch geol. reichsans!. , 55, 153188, wien. schubert, r.j. (1905b): die geologisehe verhalt­ nisse des norddalmatinischcn kllstenrei fcns zclrilo­ castelvcnicr-razanae und cler scoliengruppe raza­ nae.vcrhandlungen geol. re ic hsans!. , 1905/12, 272-284, wien. schub ert, r.j. (1909): erlauterungen wr geologis­ chen karte der ostcrr. -llngar. monarch ic, novigrad­ benkovae, 1:75.000.geol. reichsans!., wicn, 26 p. schubert, r.i. (1910): erlall terungen wr geologis­ chen karte del' oestcrr.-llngar. monarchic, meclak­ sv. rok, 1:75.000.geol. reichsans!., wicn , 32 p. schuil ert, r.j. & waagen, l. (1912): pago. geo­ logische spezialkartc del' osterreichisch-ungarigabie & zupanic: nearshore deposits in the middle eocene clastic succession ... sc he ll monarchic, 1:75 ,000. geo!. reichsanst., wien. schubert, r.j. & waagen, l. (1913): erlautcrun­ gen zur geologischen karle del' oeslerr.-ungar. monarchic, pago, 1:75.000.geol. reichsanst. , wien, 32 p. short, a.d. (1984): beach and nearshore facies : southeast austral ia. marine geol., 60, 261-182. sikic, d. ( 1969): uber die entwicklung des paliiogens und die lutetischen bewegungen in del' nordlichen dalmatien) (in croal, germ. summary).geo!. vje­ snik, 22, 309-331. walker, r.g. & punt, a.g. (1992): waveand storm-dominated shallow marine systems.in: w a193 lker, r.g. & james, n.p. (cds.): facies models, response to sea-level change. geological associa­ tion of canada, si. john's, 219-238. winn, r.d.jr. (1991): storm deposition iii marine sand sheets: wall creek member, frontier forma­ tion, powder river basin, wyoming .j. sedim. petrol., 61, 86-101. zupanic, j. & babic, lj . (1991): cross-bedded sandstones deposited by tidal currents in the eocene of the outcr dinarides (island of rab, croatia).­ geol. vjesnik, 44, 235 -245. manuscript received june 20, 1998. revised manuscript accepted november 23, 1998. 194 geologia croatica sin i geol. croat. soil !os 110 2 figs. zagreb 1997 the morphogenesis of submarine springs in the bay of kastela, croatia franjo fritz i and stjepan bahun' key words: submarine spring (vrujja), morphogenesis, hanging barrier, coastal karst spring, adriatic sea, croatia. abstract offshore, in the !jay of kastela, karst groundwater, which initial­ ly flowed under a hanging karst barrier, flows out from two subma­ rinc springs. the waler !lows from fissures enlarged by corrosion and erosion at siles (hal were previollsly coastal karst springs. they were submerged due 10 sea level rise at least 7,000 years ago and, since ihallimc, they function as submarine springs, at about 32-35 iii below sea level. 1. introduction in the bay or kastela, which extends between split and trogir, two submarine springs (or vrl/ljas as such watcr phcnomena are called in the croatian adriatic coast) occur (fig. 1). the submarine spring arbanija is about 800 m and the slatina about 3200 m from the mainland. the data on their depth differ. after alfirevic (1960), the both submarine springs dis­ charge from the bottoms of doline-like depressions: arbanija at 35 m and slatina 32 m below sea level. breznik (1973) mentioned that the arbanija is at 32 m and the slatina at 39 iii depth. both authors concur that the kastela bay bottom around the submarine springs is mainly flat and about 15 m below sea level. thc depth differences of the submarine springs (-32, 35 , and -39 m) are unimportant in the interpretation of submarine spri ng morphogenesis, thcrcfore, alfirevic's measured data (breznik did not mcasure them; pers. comm.) will be used in continuation. the submarine springs are intermittent and, in the winter, they are of a large size, and thus probably have large discharge rates. alfirevic (1966) observed the activity of these submarine springs once a month during the hydrological ycar 1963-64 and states that they became active between 20 november and 18 dccember 1963 and ceascd to discharge between 16 april and 18 may 1964. during a wet period, the author recorded a i institute of geology, sachsova 2, i-ir-ioooo zagreb, croatia . 2 department of geology and palacontology, faculty of sciences, zvonimirova g, hr ioooo zagreb, croatia. sea water sink into the submarine spring arbanija and required this to be confirmed by tracing (alfirevic, 1969). the endeavour was not successful due to poor visibility and a low sink rate. furthermore, with regard to the submarine spring activity, he concludes that "two time periods can be sharply distinguished: the winter period including thc latc autumn and eady spring and the summer period with the late spring and early autumn". alfirevic (1966) also states that the sur­ face water is warmer than the bottom water during win­ ter activity (the coldest waler was that from the arbani­ ja, measured in february, at 10.6°c), which is the con­ verse situation to that of thc surrounding sea water. in the summer, during thc submarine spring "rest" (i.c. inactivity), the temperature of the submarine spring water equals that of the surrounding sea (in the arbani­ ja, the maximum in septcmber was 24.4°c). these two periods can also be differentiated in terms of salinity, during the winter, the sea has a normal sali nity distribu­ tion (the surface water is less saline and the emerged groundwater more saline) while the submarine spring water has the opposite situation. low salinity values calise the appearance of frost in the central part of the kastcla bay when special meteorological conditions occur. in general, sea water is more saline during the summer than in the winter. in september 1971, alfirevic succeeded in confirm­ ing the water sink in the arbanija submarine spring (mijatovic, pcrs. comm. 1972). 20 kg of sodium llu­ oreseein was used on that occasion and it gradually dis­ appeared into the submarine spring. it was proof that this submarine spring is also a ponor (swallow hole), i.c. that it is an estavelle. 2. geological and palaeogeographic events a large volume of fresh water flows out from the mentioned submarine springs which, no doubt, is karst groundwater derived from the hinterland (fig. 1), since the whole coast and a part of the offshore bay o[ kastela is composed of impermeable eocene flysch deposits, overlain by a permeable cretaceous-palaeo­ gene carbonate complex, the flysch deposits provide a hydrogeological barrier [or mainland karst groundwater. thereforc, the groundwater, on its way 10 the submarine 106 catchment area of vruljas and pantan spring i i sliv vrulja i izvora pantan catchment area of springs jadro and zrnovnica i sliv izvora jadro i zrnovnica k o z j a b a 2 geologia croatica 50/1 k 3 4 5km s-=l d ~1 \, 3 fi 5 <>--06 ...j,......j... 7 fig. 1 hydrogeo logical map of" the bay of kastcla, southern croalia. legend: 1) impclmeabje rocks (eocene flysch); 2) permeable crclaccous­ palaeogene carbonate rocks; 3) brackish spri ng, pcrmancm; 4) brackish spring, intcrmi!lcnl; 5) submarine spring; 6) watershed; 7) major reverse fault. spri ngs, must pass beneath those impermeable rocks (figs. 1 and 2). the barrier in one part does nol extend deeply enough underground and forms a "hanging" bar­ rier. from this point laterally, the flysc h deposits have function of a true (entire) barrier. under these condi­ tions, a large volume of karst groundwater, partly reta rded by flysch deposits ill the western part of the bay of kastela, is drained towards the hanging hydro­ geological barrier. taking into account the present groundwater discharge from the drainage basin pantan­ sianac-submarine springs, on average from 1>30 m3/s of brackish water flowed out from these submarine springs (fritz et ai., 1993). were earlier precipitation more abundant, even greater rates of submarine spring discharges may be assumed. if the origin or these submarine springs is cons id­ ered, we have to return to not too far past, to the period between the last glacial stage and the present condit ions in the areas wherc karst groundwater had hydrogeologi­ cally open pass towards its erosional base towards the sea. as a ru le, w ith some exceptions caused by local hydrogeological conditions, the sea level is the erosion­ al basis for karst groundwater and, below it, there is no recent karstification that would penetrate toward greatcr depths. under such conditions, the karst springs of wiinn glacial age were mai nly coastal brackish spri ngs as are the present springs. meanwhile, thc altitude of the erosional base has changed due to the influence of sea level fluctuations (eustatic changes) and/or because of tectonic movcment of the land surface. it refers pri­ mordially to the question of whether the present ero­ sional basis is also the karstification basis or it is si tuat­ ed in an al ready karstified medium. since we have no more accurate data about neotectonic movements in this region, we shall accept the known and wide acknow­ ledged data presented by segota (1962, 1968) and segota & filipc]c (1991) on sea level fluctuation from the wiirm till the recent time, which states that all the old coastal springs would have been submerged, becoming submarine springs due to a global sea level risc betwecn the wurnl and approximately 1,000 years ago. this resulled in a gradual migration of the subma­ rine springs in the direction of the present coastl ine. as a result of the hydrogeological conditions in karst terrains, the sea level change (coastal movement, or rather the movement of the erosional base) is always accompanied by the appearance of new coastal springs. from a primordial spring, several hydraulically con~ nee led submarine springs could have been formed, as well as the coastal spring occurring at the present coast. 1 fritz 1& bahull: the morphogenesis of submarine springs ill the bay of kastela, croatia 107 1m) .. 100 plano bay of kastela kastelanski zaljev slanae arbanija slatina ---·ik: yxx <x ~ ~99 :88 :88600( :& ~ :ssz<95o xx:x <xx o -100 """"'~i iii i -~ 1 t fig. 2 schematic hydrogeological cross section, legend: i) impermeable rocks (eocene llysch); 2) permeable cretaceous-palaeogene rocks; 3) submarine spring; 4) assumed groundwater llow direction during rainy season; 5) assumed position of the boundary between flysch and limcstoncs. therefore, the most distant submarine springs graduajly become inactive or are intermittently active, during the maximal rates of mainland water flow. this is the rea­ soil why most present submarine springs are situated relatively near the prcsent coastline, and also why a small number of them are pennanently active and why the largest portion of karst groundwater flowing from the mainland hinterland during dry seasons does not emerge from submarine springs but along the coastline, from brackish coastal springs, the submarine springs in the bay of kastela differ considerably from the described scheme of the appear­ ance of croat ian submarine springs because their posi­ tion has not changed during the holocene. such a fact, in the genesis of kars t phenomena, is not surprising in this area as the result of the desc ri bed hydrogeological conditions including especially the groundwater flow towards the considered submarine springs (fig. 2). the submarine spring arbanija occurs as close to the main­ land as is at all possible. it appears in the boundary zone between permeablc carbonate and impermeable flysch deposits, even within marginal eocene flysch deposits (alfirevic, 1966). the submarine spring slatina is about 3500 m from the mainland. it is , according to the available data, the most distant adriat­ ic submarine spring to which groundwater flows from the mainland. the true siluation is probably more com­ plex, particularly in the zone between the arbanija and sial ina submarine springs, but we do not have more detailed data on the hydrogeology of this part of the sludyarea. thc reconstruction of sea level fluctuations , as men­ tioned above, indicates that the beginning of the recent sea level rise occurred after the last glacial stage, some 25,000 years ago, and it has risen approximately 96 m (segota, 1968). the spot altitudes where water cmerges from the subma rin e springs arc -35 or -32 m (arbanija) and -32 or -39 m (slatina) arter alfirevic (1966) nad breznik (1973). this indicates thai both submarine springs werc formed after the last glacial stage, i.c. during the first part of the last 25,000 years, or 10,000 i 1,000 years ago according to segota (1968). since then, this area has becn submerged and these submarine springs have definitely been formed from older springs. the springs, which preceded the present submarine springs, ceased to function over two time periods in the bay of kastela. the first period is re lated to the riss glacial stage, i.e. to the penultimate fall of the global sea level, belwcen 200,000 and 110,000 years before the present time, when the sea level fell 10 the deepest position, to -110 m below the present level. if the pre­ sent submarine springs were formed during the penulti­ mate glacial, i.e. between about 200,000 and 110,000 years ago, when they were al ready submarine springs this could have occurred between 11,000 and 75,000 years ago. that is to say, then the sea level was higher than their surface sites, and the highest elevation (+17 m) was reached about 96,700 years ago. in this case, the day of kastela depression and the area where the present submarine spring occur would have twice been an erosional basis for the karstification of the present drainage basin of the neighbouring springs pantan and slanac and the submarine springs arbanija and slatina (fig. 1). the second period is related to the wurm glacial stage, i,e. to the last sea-level [all below the spring site, or below the site of the present submarine springs (about 75,000 years ago). since then, the most intensive erosion-corrosion processes, or optimal climatic condi­ tions for the development of springs within the palaeodepression or the bay of kaste la occurred after the lowest sea level position (96.4 m below the present sea level occurred some 25,000 years ago) unti ii the submergence of the spri ngs, 10,000 to ! 1,000 years ago, i.e. during the latest pleistocene. the transforma­ tion of springs into submarine springs coincide approxi­ mately with the beginning of the early holocene, when the climatic conditions became relatively calm. \vith the gradual sea-level rise (i.e. the erosional base for the neighbouring karst groundwater) the groundwater table within the carbonate hinterland also gradually rose. this resulted with ever longer siphonal groundwater tlow paths to the submarine springs. as a result of furids ther sealevel ri sc, karst groundwater began to flow out on the land itself, at the upstream side of the hanging barrier, first from the pantan spring and later from the slanae spri ng (fig. i). the submarine sp ring activity decreases with the recent sea-level rise and karst groundwater begins to flow out at increasing rates from higher altitudes, e.g. from the pantan spring. the submarine springs afc nowadays active only during the rainy season and the pantan spring has become a signi fi cant permanent karst brackish spring. during dry seasons, as mentioned above, the submarine spring arbanija even draws in sea water, so this water phenomenon is in fact a submarine est3vclle (brackish water flows out during the winter while sea water sinks into it during the summer). this term, a submarine es tavelle, has not yet been used in the literature; it has becn known only as the submarine spring arbanija. the questions of whether the submarine springs in the bay of kastcla have been active during one or two periods of time, and whether the groundwater conduits towards these submarine springs were karstified during one or two cycles, have not been resolved. the appear­ ance of submarine springs in the bay of kastela at only two sites, and the appcarance of younger springs at the contact between impenneable and permeable rocks at the "upstream" part of the barrier also at only two sites (the pantan spring at the alti tude of 2.7 m above sca lcvel and the intermittent spring slanac even about 30 m above sea level), together with a relatively low sea­ level elevat ion (+ 17 m) suggests that thc water conduits towards the submarine spri ngs were dcveloped during the second part of time period which began about 75,000 years ago. the most intensive karstification period occurred between about 25,000 and 10,000 years ago, at the end of the pleistocene. during this time, only the karst springs at the present submarine spring sites were active. according to the concept that the sub­ marine springs are active only from the last sea-level fall, they then became ac tive by the beginni ng of the holocene and are of holocene age. such a conclusion is in accord wi th the idea that the karstification cycle from the end of the pleistocene and its continuation wi thi n the holocene is related to the development of groundwater flow conduits towards the present karst springs and that the present re lief was formed during this pcriod (bahun & fritz, 1987; fritz, 1991, 1992). 3. the morphogenesis of submarine springs and their development thc morphology and geology of the area where the submarine spri ngs appear has been studied by alfire­ vic (j 966, 1969). he writes that the morphologic aspect of submarine springs coincide with the fossil ponikvas (doli nes, sinkholes) formed during the conti­ nental phases of the littoral dinaric karst and that the geologia croatica 50/1 submerged submarine springs, according to their litho­ logical and micropaleontological compos ition, occur within eocene marly limestones which, according to their geological structure, coincide with the flysch syn­ cline of the bay of kastela. furthermore, the author writes that the divers recorded "the rocky edge of a con­ ical depression" i.c. the ex istence of the funnel of a compact lithological composition (1969, p. 189). further exploration has not been performed, thus, according to the mentioned data, the "ponikvas", from where the submarine spri ngs emerge, should occur within fl ysch deposits. it would be exceptional for the submarine springs to appear out of calcareous­ dolomitic rocks. our opinion is that there are interlayers of calcarcous rocks, close to the considered submarine springs, through which groundwater nows from the hinterland, beneath the impermeable rocks, to the spri ngs or submari ne springs, le. that the submarine springs occur within the contact zone of impermeable calcareous and impermeable flysch deposits. the impermeable rocks comprise the whole area between the submarine spring arbanija (at the village of divu­ ije) and the springs slanae and pantan (figs. 1 and 2). ii is not important whether the final condui ts to the sub­ marine springs occur in limestones of the cretaceous­ palaeogene complex or calcareous breccias which are a constituent of flysch . in the both cases, the now of water towards the springs (submarine springs) is siphonal and it passes through calcareous rocks. the submarine spring water ilows out, as also from most karst coastal springs in the adriatic littoral, mostly along a reverse or thrust contact of permeable and impermeable rocks, probably from a calcareous inter­ layer within, in general, impermeable t1ysch deposits. within our concept of the origin of subm arine springs in the adriatic sea, as described above, the sub­ marine springs are submerged earl ier karst coastal springs. from that point of view, the depths of subma­ rine springs: -32 m and -35 m (after alfirevic, 1966) and even -39 m and -32 m (after breznik, 1973) have to be analyzed taking into account the pre­ sent depths of the bollom of the bay of kastela, 15 m below sea leve l, because the fanner springs were defi­ nitely submerged only when the bay of kastela bottom was submerged. therefore, the dilemma of the depth of these submarine springs should be resolved by the assumption that the fomler springs were at the level of palaeorelief, i.e. at the contemporaneous level of the bay of kastela bottom, naturally without the sediments deposited later. therefore, it should be said that a sub­ marine spring is a spot at the sea bottom from whcre permanently or intermittently fresh or brackish water flows out, as it happens in brackish coastal springs in the mainland. thus, it is not important how deep a water bearing fracture penetrates below the land surface or sea bottom or what size it is. in order to display a comparison, let us see what happens in a major coastal brackish spri ng, e.g. the pantan spring, especially regarding its "morphological i fri tl. l& l3ahun: thc morphogencs is of submarine springs in the bay of kastela. croat ia 109 aspect". \vater emerges from the bottom of a lake 30 x 60 m in size that is 2.7 iii abovc sea level and about 1213 iii below the lake water surface. this water emerges from the base or a depression, 9-10 iii below sea level, fro m a 40 m long frac ture (fritz e t ai. , 1993) . the spring is situatcd in a thrust contact between permeable limestones o f the palaeogene-cretaceous complex and impermeab le fly sch, whil e the lake and frac ture are within fl ysch deposits. the pant an spring morphology is interesting. the spring site has a funnel fonn , resem­ bling a ponikva (do line, s inkhole) and water emerges from the bottom of this "funnel" , rrom a widened frac ­ ture . consequently, almost the same re li e f form , observed at the submarine spri ngs in the bay of kastela, also occurs at ascend ing springs or at springs with siphon al conduit s, as observed in the pantan spring. similar morphological form s also occur at the jadro and ombla springs which are the most well know n croat ian karst spri ngs. the morphology of the bottom of the submarine springs in the bay of kastela resembles morc a widened fracturc, as at most ascend ­ ing karst springs, than a ponikva. thi s can be concluded from the photos of ihe s ubmarine spring s latin3 (j\ lfirevi c, 1966, 1969) and from the echogram of the submarine spring arbanija (alfirevic, 1969). in addition, it is necessary to emphasize lhal lhe genesis of ponikvas, as karst re li e f form s, is difficult to explain when they occur within jlysch deposits. the refore, the present submarinc springs, do not deri ve from ponikvas. they arc frac tures widened by water and initiated by tectonics in the zones of thrust and reverse movements and through which water flew toward coastal springs during earlicr time phases. by considering the morphogenesis of these subma· rine springs, it may be concluded that the submarine springs (coas tal springs) of the bay of kastela wcre the erosional base for the pertinent groundwater during the pleistocene epoc h. in the holocene, the erosional base g raduall y rose to a hig her altit ude, where the pantan and slanac springs appeared as outl ets for the earlier formed "privileged" groundwater condui ts serving the submarine springs. this is why in the immediate hinter­ land of the pantan and s ianae springs it is assumed that th e occurrence of a hi ghest porosity of calcareous rocks, the rocks of "privileged" groundwater nows is at a lower altitude than the present sea level. fuj1helmore, until re lati vely recentl y the largest portion or ground ­ water deri ved from the entire drainage basin probabl y fl owed through siphonal conduits toward the submarine s prings in the bay of kastela. thi s flo w enab led the development of recent karstification in the hinterland of the submarin e sprin gs reachin g unknown depths beneath and behind the mentioned hanging hydrogeo­ logical barrier. when the submarine springs are inactive, sea water mi grates landward through the whole calcareous per­ meable mediulll occurring below the hanging hydroge· o log ical barrie r, prim aril y through the s iphonal con­ duit s. thi s sea water intru sion vari es durin g the ycar because of different hydraulic conditions and the same happens with the fl ow of fresh (brackish) watcr toward the submarine springs, both causing complex relations between sa line and fresh water. intermitte nt flows o f brackish water from the s lanae spring occurring 30 m above sea level (be ing the g loba l a ltitude record for a coastal brackish spring fritz, 1992 , 1994) , is the consequence of the rapid infl ow of large quantities of water from the calcareous h inte rland under the described hydrogeological conditions. the higher water salin ity in the sianac spring than the pantan spring at the same time together wit h the described submarine spring genesis indicate that the route of sea water pene­ tration int o the land is from the submarine springs, to the sianac spring, then furth er into the land, mainl y separately from the underground nows toward the pan­ tan spr ing. t he geographic shift and rise in altitude of the erosional base from the submarine springs toward the pantan and sianae springs, together with the gradual increase in discharge rate at the pantan spring are the results of the last sea level ri se. the submarine springs that had earlier been permanent graduall y became inte r­ mitt ent and periods of their inac tivity became ever longer thus the submarine springs gradually died orr. then, the permeable strata situated in the hinterland o f the hang in g hydrogeo logical barrie r became large ly filled with sea water and this is one of the reasons why the brackish sianac spring occurs at such a high alti tude above sea level. it is difficu lt to predi c t whether th e s ubmarine springs in the bay of kaste la will die off entire ly by the end of the present interg lacial stage when the sea level should rise by an additional 1.17111 (segota , 1968), but , there is no doubt that the pcri ­ ods of submarine spri ng inac tivity wi ll become longer and the coastal panlan spring will di scharge mo re water. the sea level ri se will probably be greater than [ .17 m due to the still unknown mag nitude of the at mospheric temperatu re rise caused by human activity_ 4. conclusion the submarine sp rings of the bay of kastela arc unusually fa r from the mainl and and the grou ndwater on which thcir activity is dependent. they arc a conse­ q uence or many reverse and ajlochthono us rela ti o ns wi th in thc cretaceous-palaeogene carbonate comp lex and eocene nysch deposits. thus, the coastal area and a large part of the bottom of the bay of kastela are built o r impenneable fl ysch deposits. this is the reason why part of the groundwater percolates above a flysch barri­ er (th e pan tan and sianac spri ngs ) and the o th er part nows beneath this ba rrier to the subma rine arbanija and s latina springs in the bay. the published data on the submarine spring mo r­ phology s upport the idea that the subm arine sprin gs were form ed when the bottom o f the prese nt bay of kastela was above sea level. t he submarine spring morphology can be exp lained as a result of the erosion 110 and corrosion of tectonic frac tures along which ascend­ ing water flowed toward original karst springs within the bay of kaste la paiaeociepress ion. during the last sea level rise , these springs were submerged by the sea and so became submarine springs. the question of the age of the submarine spring remains open. the supposed age of 10.000 to 11.000 years is based on published data that the submarine springs are between 32 to 35 iii below present sea level and that they were active on ly aetcr the last g lac ial s tage. if the morphoge netic concept described in this paper is accepted, i.e. that the present submarine springs are submerged ascending karst springs, then the submarine spri ngs are younger, because water flowed out from the former springs at the level of the present bottom of the bay of kastela, i.e. about 15 m bclow the present sea level. the sea level reached that elevation soillc 7,000 years ago (segota, 1968; segot a & filipcic, 1991), meaning that the former springs have ex is ted as submarine springs during the last 7,000 years, thi s is, probably, the real age of submarine spring activity in the bay of kastela, the difference in these proposed ages of the submarine springs, obvious­ ly , is not large whethe r we accept that the submarine spri ngs are situated a little more than 30 m (10,000 to 11,000 years) or about 15 m below the present sea level (7,000 years) because the sea leve l rise decelerates with time. after segota (1968), during the present inter­ g lacial stage, the sea level w ill continue to rise during the next 1,900 years and it will only be approximately 1.17 m higher than presenl. during this period, the sub­ marine springs wil l become more inactive, while ever more water wi llllow out from the pantan spring during the rainy seasons, and the re fore, the submarine springs will most probably "die off'. acknowledgments the author wishes to express his appreciation to lui gi tulipano. from the istituto di geologia appli­ cat a e geotechnica, politecnico di bari, italia and to bozidar biondlc. ivo velic and ante sar1n from the inst itute of geology, zagreb, croatia for all their thorough and effective remarks and help. also grateful thanks to julie robson for her language editing. geologia cro:l1ica 5011 6. references alfirevic, s. (1966): les sources solis-marine de la baie de kastela.acta adriatica. 10/2. 1-38, split. alfirevic. s. (1969): jadranske vrulje u vodnom rezimu dinarskog priobalnog krsa i njihova prob­ lematika.krs jugos!., 6, 183-206. zagreb. breznik. m. (1973): nastanak zaslanjen ih kraskih izvirov in njihova sanacija.geologija, razprave in porocila, 16.83-186, ljubljana. bahun, s. & fritz, f. (1987): postanak izvora 1i dinarskom orogenskom akumuliranom krsu. krs. j ugos!.. 12/2, 27-37. zagreb. fritz. f. (1991): utjecaj recentnog okrsavanja na zah­ vacanjc vodc.geo!. vjcsnik. 44. 281-288. fritz. f. (1992): effect of recent sea level change on the development of karst phenomena.proc. intern. symp. "geomorphology and sea" and meeting geo­ morpho comm. carpatho-balcan countries, mali losinj. 85-92. zagreb. fritz. f. (1994): on the appearance of a brackish spring 30 m above sea level near trogir (southern croatia).geologia croatica, 47/2, 215-220. fritz, f., renic, a. & pav1c1c, a. (1993): hydro­ geology of the hinterland of sibenik and trogir. ­ geologia croatica. 46/2. 291-306. segota, t. (1968): morska razina u holocenu i mla­ dem virmu .geografski glasnik, 30, 15 -39, zagreb. segota, t. (1982): razina mora i vertikalno gibanje dna jadranskog mora od ris -v irmskog interglacijala do danas.geol. vjesnik. 35. 93-109. segota, t. & filipcic, a. (1991): a rheoloski i geoloski pokazatelji holocenskog polozaja razine mora na istocnoj obali jadranskog 1110ra. rad hazu. 458 (raz. prir. znan .• 25), 149172. zagreb. manuscript received april 4, 1996. revised manuscript accepted apri l 28. 1997. geol. croat. 49/2 289 293 3 figs. zagreb 1996 revielv paper economic evaluation of oil exploration projects arso putnikovic and hrvoje lipov ac key words: economic evaluation, reserve size, monte-carlo simulation. abstract this paper has a goa l 10 describe, in brief, the mathematical cal­ culations in economic evaluation of oi l exploration projects. described arc calculation of geological risks, reserve size, develop­ ment costs, production curves, production sharing and discoullting. mathematical methods include cxpcc(cd value theory, probability the­ ory and montc carlo simulation . all is put toget her in ihe fonn of a compllicr data input sheet, as a single procedure with ihe purpose of giving the ,1ilswcr is expected profit from a potential pro spec i big enough to justify the risk and money invested ill exploration. i. introduction the economics of oil exp loration is the topic of many articlcs and academic discussions. therc are many computer programs available on the markct, somc of which are very complex and can compute prof­ itability in dctail. in exploration projects, which provc to be unprofitable to develop, the cause of failure is most frequcntly the incorrect evaluation of geological factors. however, it can be the ease that insuffie ienl and/or ovcrcomplex economic evaluation is the cause of such unprocitability, especially in marginal projects. th e method described here is recommended for the eval uation of exploration projects because of its sim ­ plicity and versatility of use in diferent fiscal-tax regimes. 2. definition of phases the procedure of economic evaluation of oil explo­ ration projects can be divided into the following phases: phase 1. geological estimates of the probability of suc­ cess (factors for: the existence of a valid trap, reser­ voir quality, seal, source rock, favourable migration coincidence of factors 10 produce a hydrocarbon accumulation); ina -naftaplin, seklor za islrazivanjc i razvoj, subiceva 29, i-ir10000 zagreb, croatia. proceedings kljucnc rijcci: ckonornska procjena, velicina rezervi, monte-carlo racunica. sazetak rad ima za eilj opisali matemalicki postupak u ekonomskoj ocjeni naftnih istrazllih projckala. opisano jc racunanje s gcoloskim rizicima, racunanje kolicinc zaliha, razradnih lroskova, krivulja proi7.vodnje, raclll1anjc podjele proizvodnje i diskonliranjc. ukljucene sll postavke teorije ocek iv anc vrijednosti, teorijc vjcrojatnosti i monle-carlo sirnulacije. svc jc objeclinjeno ii jedinstveni poslupak, u obliku kompjulorskog programa, koji ima za cilj odgovoriti na pitanje jc ii occkivana dobil projekt<l dovoljno velika cia opravda ulaganje kapilala ii istra7.ivanja. phase 2. eva luation of exploration costs (bonuses, seis­ mic, drilling); phase 3. evaluation of reserve parametcrs (acreage, bed thickness, accumulations); phase 4. evaluation of field development parameters (price of oil, price of development well, required number of wells , cost of other dcvelopment, wcll li fc, perccntage of the oil sharing and the participation in the profit, taxes, choicc of the discount rate); phase 5. compilation and intcgration calculation (probability theory, expected values and monte carlo multiplication's) and conclusion . 3. explanation of the calculation procedure in each phase disregarding the problcm of [he evaluation of a parameters' sizes, the calculation procedure for each phase is as follows. phase i the probable factors are: • existence of a valid trap; reservoir quality; seal; • source rock; • favourable migration co incidence or factor to pro­ ducc a hydrocarbon accuillulation. 290 geological estimates of probabilities arc expressed as a percentage and, assuming that the evaluated geo­ logical probabilities arc independent, we can apply the multiplication theorem which will give the complex value discovery probability. each probability factor can be subdivided into morc components but in such a case the overall probability of success (discovery probability) will be jower. as a rule each factor is expressed on a scale from 590%. 80-90% probability indicates a good factor (vcry low risk), 60-80% is probable (low risk), 40-60% is possible (medium risk), 20-40% is likely (high risk) and 5-20% represents the unlikely presence of a factor (very high risk). the comparison of dihercnt exploration projects has sense only if probabilities are expressed using the same number of factors. phase 2 the explorat ion costs arc evaluated from experience and current market prices. the sum of these also reprc­ sent the risk that will have to be taken in case of failure as expressed financially. many otherwise attractive pro­ jects with a high expected value can be dropped because of this parameter alone, as the investor simply feels the amount or risk moncy is to high for him to take. phase 3 profit eva lu ation starts with thc evaluation of the sizc of the reserves. here it is possible to: a) eva luate the size or the reserves based on neigh­ bouring fields so in this case no further compl icated calculations are necessary. b) evaluate the parameters of reserve calculations, and by multiplication using the volumetric formula, reach the total size of the reserves. reserves (m)) = acreage x bed thickness x porosity x oil saturation x perccntagc of recoverab ility of total reserve x volumetric factor. c) many authors consider that the eva luation of paramcters such as a unique size does not represent the possible size of reserves, (as we can not be certain that the chosen size is realistic), but they recommend the parameters to be evaluated in the range from-to with or without stress on the most probable value, and that the usc or the special multipl ication procedure known as "montc carlo simu lation" lcads to the most probable reserves sizes. the monte carlo cal cui at ion procedure can be explained in the following way: imagine a graph with x and y axes; the first parameter is put on x axis and its smallest and biggest value should be marked; y axis represents probability in the range from 0% to 100%; geologia cronlica 49/2 100 % r----,."":-r--~~--------c_---___, 80% .~ 60% :g o o 0: 40% 20 % 2% o%'--"_l ~ 41 49 ~ u n ~ 87 m 102 recoverable reserves (mm nil) fig. 1 recoverable rese rves for prospect "a", north africa. the cumulative probabil ity is set for all the parameter va lues on the x-axis slarting from the smallest one, by answering to the question "how sure are we lhat the parameter value is at least that grea t". 'vve should get a declining line with thc 100% valucs on thc y­ axis up to 0% for the largest value; a random number in the rangc from 0 to 1 is chosen. ii the chosen random number is i.e. 0.23, the value 23% on the y axis must be found; from the drawn cumulative probability (declining lines) parameter values shou ld be read on the x-axis; the procedure is repeated for all the parameters; when the values are read off on the basis of the random number for all the parameters enteri ng the for­ mula, the value is calculated and the result is written down. it is necessary to mention that it is not correct to multiply all the parameters with the same random number. when the same random number is used all the time, then the small value of one parameter would be multiplied with a small value of other parameters, and the aim that we want to accompl ish is the result of testing with all the possible combi nations of the in­ coming parameters (the biggest x the biggest, the biggest x the smallest, the smallest x the smallest); the procedure should be repeated until a satisfac tory number or written results is reached, usually 10001500 times; the written results are summed and the arithmetic average is calculated through the probability distribu­ tion in the following way: the groups are establ ished (classes) in which the sin­ gle results are sorted and this provides us the infonna­ tion of how many single results each group contains. if the procedure is show n graphically throu gh the columns, the class with the highest column is so called modal class or the class where the most com ­ mon probability is found; the class is calculated as a percentage of the total number of cases and this number is multiplied with the middle number (lower class boundary + (upper lower boundary) / 2) of each class; pulllikovic & lipov:1c: economic ev:llu:liion of oil exl>lor~lion projecl.~ 291 "al;d "ad m;n max auahiv ;1 90 120 i , ; i " ; i " 1.3 22 50 2:500 ~ 3tod ~bt9 ; 'o~ ; ooj i ; i.", ~ in" aav ; i ~ [(j]jqjjjjfi lo027' .006577 m;n moan max = -, 1 ",,"'., fmmm' l 1.b b.7 1b. ~ 3:5i< .. 6% numb" 01 w,ii, 9 29 75 = ....... 70ii 75% om" fmm$1 -. 52 26' i% 9% ~ 19% f'ia[ue of loss(mm$f 3 jq 1.2. 1.3 , of profit imm$1 9 ) value of 6 ~ 1 vad,bla r;;;;t;;;w =fm'/d,vl m. ..--;;;:n max prospect: albania onshore lis 120 i% 110 i% 95 i% 90 1i ii% be • • , m"", i i of 36 dg,api oil ig'~~:'~ feet*o.02832=cubic metre metre*35.31 =cubic feet i iu ~eati i" " roig.2 economic cvaluat ion by montc carlo simu lati on; prospect: a lbania onshore. ibtu ~ ;:~:; ;;;:;,:;;;'i;;';~':o~;~p:~,c;~ iko"' ~, , i 0., c .. the sum o f the results gives the expected value or arithmetic average of a ll the results. the advantage of the monic carlo method versus the eval uation of reserve size based on the most proba­ blc parameter va luc (dcscri bed in b) is tlwt it also takes into considcration all minimal and maximal parameter valucs. in thc dcsc ri bed cxample (rig. i) instead or a value of 5] x i 0" m ~ ror the most probable reserve size wc rcached the val ue of 64 x j ali m~ . us ing the montc­ ca rlo s imu lation we proved that a highe r val ue o f reserves was probable. pi-lase4 th e required number of well s and th e ex pecled profit is calculated simultaneou sly to the quantification of expected reserves. the numbe r of well s is dete r­ mined from the data o r initi a l and minimal da il y pro­ duc tion or cach well (n ewendorp, 1975) . using " darcy 's law " a co rrelati on is made between the ex pected value or the bed thickness and the initial daily product ion. the rormula for the exponent ial production curve is being used and it is corrected for the number of ex pected negative well s (n ewen dorp, 1975). the result of the poss ibl e well number can be checked on remrv .. (nmm', th e basis of data on the usual density of the develop­ meill well s grid applied to study area. profit is calculat­ ed on the basis o f the contractual terms deta iling the product ion percentages of profit share and is d iscounted at the chosen rate. 4. conclusion (phase 5) the ultimate aim is a comparison of expected ga in versus risk. in order to do thi s the expected va lue o f prorit (ar ithmetic average of profit multiplied by the probabil ity of di scovery) was compared with the excepted value of loss (m ultiplication of the exploration cost w ith the probabilit y of a ncgative we ll ) . .if the ex pected profitability valuc is higher than the ex pected loss va lue a decision can be undertaken as 10 either undertaki ng the ri sk or funile r evaluation. t wo cases are described as ill ust rations: the albania onshore (fig. 2) and o rrshore arrica (fi g . 3). the rig­ ures al so represent computer data input sheets. results arc gi ven in graphical and numcrical fo rm (minimum, maximum and most li kely size o f reserves). expected val ue of loss and profi t are expressed in monetary unit s or uss. 292 geologia croatica 49/2 i i valid , i i i ii sou,"a m,k , ~ i , , ii ~ ,oou, well ~ ii olal '0"" mio ~ , area ('q.km) 3' ~ oel pay i oil ,.,ove>y 0.012802 0.02 da",'ty 1 (ra,a>ve, (mmm') 29.4 69.5 110.3 po>o,11y % lb.oo/< 20% 22% loumbar otwall' 36 b2 287 (i·sw) 55% 60% 65% ipro," (mm$) 529 1151 -rt% 15% 20% 30% , value of loss (mms) 9 bo .16 1.2 1.25 , value of profit (mms) 76 9a, ta,q,) , value of projec (mm$) 67 i igraph, , i var'able, ,i vor'able oel pay i'oil.prod, "/dey) metre, m'n max prospect: africa offshore 0% 100 500 600 , 10% 95 450 490 50% bo 35 450 90% 65 200 300 60 100 150 '"~ ,melre, metr." 0'7., , cub', , "'''. ",'n btu'; 'u . i of 36 dg.api oil , mei re i feet "eilt oo,'~ ", fig. 3 economic evaluation by montc carlo simulation: btu. per cu~!c foot ft 8.90196:=kilocel per c.m. ik,al per cub', metre'o.i12335=btu per of. one inadequacy of the mcthod is that the political and financial risks are not being evaluated. also only the expected value of a single prospect is considercd so it docs not includc the total geological potential of the area. this can be ovcrcomc by applying separate evalu­ ations of political and financial risk (choosing an higher discount rate for example for those prospects which have such higher risks). for total evaluat ion of the geo­ logical potential of the area a series of calcu lations as described herein have to be taken for each potential prospcct and, by summing the expected values, a mea­ sure of the total geological potcntial of a certa in area can be achicvcd. 5, formulas and definitions i) definition of probability: p(d):= min the probability of the event 0 is the ratio of all the favorable cases (m) to the number of all possible cas­ es (n), where p = probability. prospect: arrica orrshore. 2) complex probability equals the probability product or each event p(d i &d2& ... &dn) = p(d i )xp(d2)x ... xp(dil) pro bability "j~i", multiplication theorem. if the events d i, d2, ... dn are independent, but they arc 110t mutually exclusive, in other words all of these or several of these, can appear sequentially, then this probability is called complex probability. 3) formulas ror estab li shing the parameter values (newendorp, 1975) based on the random nllmber (cf) if the known is: a) minimal and maximal value of parameter x: x = xmin+cf*(xmax-xmin); b) minimal, maximal andlhe most probable value of parameter x: for the x values s:; xmode x=xm in+(xmax-x111in)*sqrt(cf*(xlllodc-xrnin)/(xmax-xmin» for the x values :?: xmode x=xmin+(xmax-xmin)*( i-sqrt« i-ct)*( 1-(xmodc-m in)1 (xmax -xmin»)) putnikovic & lipov;lc: economic evaluat ion or oil exploration projects considering that if c1' .:s; (xmode-xmi n)/(x max ­ xmin) the first equat ion is used, a nd if e1' 2: (xmode-xmin)/(xmax -xmi n) the second one is app lied. e) if the known cu mul ative parameter frequ e ncy is wri!len in the shape of: value of variable: 146 150 154 163 174 cul1\u lative frequency : 0 0.4002 0.7959 0.9006 0.9674 the formula is: x=x(n)+( cf-cf(n» *(x(n+ i )-x(n»/( ef(n+ i )-ef( n» the calculation procedure is as fo llows: the random number is chosen cf (from 0 to i) the test is made if cf.:s; cf (2) ifso than n:::ol and solve the equat ion for x if not question whether cr.s; cr (3) if so than n:::o2 and solve the equation ror x if not question whether cr.s; c f (4) if so than n:::o3 and solve the equation for x if not quest ion if of <; cf (5) if so than n:::o4 and solve the equation for x if not than n:::o5 and solve the equation for x ls i 4) formula fo r the exponential declining production curve (used wh ile calculating the reserves per we ll ): a= ln(q/q :,)/t where a:::o dec linin g coeffi c ient; in :::0 natural loga ­ rithm ; qt :::0 in it ial well production (tons/year) ; (h :::0 fina l wcl! production (tons/year); t :::o production time (year). 5) rccovcrable reserves per well dcln = ( l/a)*(ql -q2) 6) number of wells per fie ld: number of wells == total reserves / deln 7) number of negative developmen t wells if the number of wells> 20 !leg = (2/15)*number of wells+ 3.33 if the number of wells .:s; 20 neg == (4/ 15)*nulllber of wells +0.67 (the numbers arc empirical) 293 8) time needed ro r the compl etion of the deve lopm ent wells ti me = number of wel ls (posi ti ve and negative)/16 (time in years) assuming that 16 we ll s per year can be completed 9) d iscounted value of the development costs: npvdeosl = development cost*e·o.i(,.,ime/2 10) discounted production value income = reserves*priee (a/(a+.dv« l _e-t .("'j))!( i-c""') a :::0 exponentia l c urve coeffi cien t; j :::0 discount rate; t :::0 time in years (field duration) ii ) discounted income npvincome = ineome*e·o.]( .. ti m r/2 12) defin it ion or the expected value 4) : the expected value of some evcnt is the multiplica­ tion or the events probability and the profit value of the same event. e.g. emv = 20%*3 mm$ = 0.6 mm$ the expected value of the decision whether or not to accept the ri sk (expected value of a decis ion altcrna­ tive) is the sum of the expected values o f all the pos­ s ible events that are the subject of the decision. e.g . sqolo*$2mm = $1 mm expected profit value 50%*-$1 mm = -$ o.smm expected value 01" loss $1 mm~$o .5mm = $o.5mm as the e xpected profit value is h ighcr than the expected loss value the decision oj" accepting the risk should be made. 6. reference newendrop. p.d. (1975): d ecis ion analysis fo r pe tro leum exploration.penwell boo ks, tul sa, 5611'. 294 geologia croatiea 49(2 lukac.indd � ab stra ct karst aquifers are heterogeneous terrains, where it is hard to assess any hydraulic parameter. therefore, a multidisciplinary approach is necessary for research on karst aquifers. the catchment area of the gacka river springs is typical dinaric karst terrain formed of karstifi ed carbonates. groundwater fl ow is mostly directed by preferential fl ow paths usually connected with main faults and fracture zones. in the presented case study, structural, geological, and tectonic characteristics were defi ned. a recession diagram was created, and the water balance was calculated. tracertest data were also used for analysis. all data were compared with the bulk hydrogeochemical and isotopic analyses of spring and surface waters. for this purpose, samples were obtained every month for one hydrological year at 17 sampling locations. processing of all these data allowed a tenable defi nition of the gacka spring catchment area. keywords: hydrogeology, karst, hydrogeochemistry, isotopic research, river gacka, croatia an estimation of groundwater type and origin of the complex karst catchment using hydrological and hydrogeochemical parameters: a case study of the gacka river springs � jasmina lukač reberski1, sanja kapelj2 and josip terzić1 1 department of hydrogeology and engineering geology, croatian geological survey, sachsova 2, 10000 zagreb, hrvatska; (jlukac@hgi-cgs.hr) 2 geotechnical faculty, hallerova aleja 7, 42000 varaždin, hrvatska doi: 10.4154/gc.2009.15 geologia croaticageologia croatica 1. introduction many diffi culties encountered during investigation of the karst area demand a multidisciplinary approach for its characterization. the signifi cant heterogeneous characteristics of the karst aquifers, in addition to ignorance about the real geometry of the underground cavities, necessitate the application of different hydrogeological methods so that indirect conclusions can be made. hydrogeochemical investigations play an important role in this approach, which enables the inspection, verifi cation, and supplementation of results from all other investigations. analyses of hydrological and hydrogeochemical data were carried out in order to characterize the gacka river springs catchment area and groundwater origin. these data were compared with earlier tracer tests that were conducted in this catchment. joint dissolution secondary porosity prevails in karst areas, which results from a combination of tectonic activity and carbonate dissolution. the size of cavities ranges from smaller fi ssures and joints, in which the fl ow is similar to the fl ow in rocks with intergranular porosity, up to broad conduits and speleological objects, in which rapid and turbulent fl ow is present. the area under consideration belongs to the croatian dinaric karst. it is situated in the lika region, which represents the hilly karst, with karst poljes (fig. 1 – detail). the croatian karst region is part of the adriatic carbonate platform – of palaeogeographic structure, which existed from geologia croatica 62/3 157–178 16 figs. 2 tabs. zagreb 2009 geologia croatica 62/3geologia croatica 158 the lower jurassic until the end of the cretaceous, representing a substantial part of the karst dinarides (velić, 2007; vlahović et al., 2005). the karst relief includes approximately 46% of the croatian state territory. the systematic research of karst has a long history of more than two hundred years. this region, with its numerous well-developed and diverse karst forms; both on the surface and underground, is unique in the world, a ‘locus typicus’. furthermore, geological scientists from all over the world, when referring to the dinaric karst, call it the ‘classical karst’. terms such as ponor, dolina, polje, and jama, which relate to karst phenomena in this region, are used in the international geological vocabulary, confi rming this unique status. (gottstein matočec et al., 2002). similar investigations in the lika and neighbouring regions were carried out by many authors (bonacci, 2001; horvatinčić et al., 1986). studies were also conducted in other types of karst areas all over the world (simsek et al., 2008; azzaz et al., 2008). the investigations and results presented here are parts of an extensive hydrogeological study used for writing a master’s thesis (lukač reberski, 2008). newly published hydrological researches suggest an underground connection between the river lika (fig. 1), streams and some of the gacka river springs (bonacci & andrić, 2008). these theories are possible, but were not researched within the presented program, but will be considered in future research. 2. geological, hydrogeological, and structural-tectonic characteristics the investigated area is composed mostly of carbonate rocks, belonging to the jurassic and cretaceous ages, and clastites of the younger paleogene (the so-called jelar deposits), which exist around gacko polje. jelar deposits indicate very dynamic conditions at the time of their formation, and they are represented as lime breccias with unsorted fragments of jurassic, cretaceous, and palaeogene sediments. lithostratigraphic members enable the separation of rocks according to hydrogeological characteristics (fig. 1). the rocks are divided according to permeability as follows: very permeable carbonate rocks are the most common types, in which limestones prevail; predominantly permeable rocks are represented by jurassic and cretaceous carbonates and palaeogene clastites, i.e. jelar deposits. jelar deposits show about 50% less permeability than the carbonates of the jurassic and cretaceous, which surround them (bahun & fritz, 1975); predominantly impermeable rocks-comprising dolomites of jurassic and cretaceous periods; impermeable deposits – found in a very small area in the eastern part of the investigation area; quaternary deposits are sorted out as a separate group with alternate properties, because their permeability varies depending on the thickness and composition. they are mostly represented in the depressions of karst poljes. by studying the neotectonic activity of the dinarides, prelogović (1989) indicated the neotectonic phases and classifi ed the active structures and faults. he separated the seismically active zones and described the tectonic movements in these areas. the recent dynamics of these areas causes the formation of new structures of the pull-apart type, which morphologically correspond to karst poljes and great sink-holes. lithological, morphological, and hydrogeological properties of rocks, the spatial and hypsometric position, and tectonics, infl uence the hydrogeological function of the area. using this approach, the complete barriers, incomplete barriers, and permeable areas can be distinguished. to determine the size of the catchment areas, the apparent velocities, and groundwater-fl ow directions, several tracings were carried out using the artifi cial tracer na-fl uorescein. because of the relatively monotonous lithology, the groundwater-fl ow directions depend more on the structural relationships than on the lithological characteristics. the area fi gu re 1: schematic hydrogeological map of the study area, with the sampling sites (position of the study area in the detail). 1 – very permeable rocks, 2 – predominantly permeable rocks, 3 – predominantly impermeable rocks, 4 – most important faults, 5 – extension zone, 6 – swallow hole (ponor) and vertical cave (pit), 7 – spring: permanent and intermittent, 8 – groundwater divide, 9 – borehole, 10 – groundwater connection (tracer test), 11 – sampling point, 12 – river. lukač reberski et al.: an estimation of groundwater type and origin of the complex karst catchment... geologia croatica 159 under study is characterized by the dinaric strike of the structures (nw–se). the tracings showed that the groundwaterfl ow direction in the greater part of the catchment area is parallel to the structures. this is due to the position of the main boundary faults, favourable to the stress direction (20°– 45°) and along which the right transcurrent shifts appear, as apart from the opening up of spaces and appearance of structures of a pull-apart type (prelogović, 1989). these fault sections play the most important roles in creation of the hydrogeological conditions in this area. in contrast, an unfavorable direction of the fault to stress direction leads to local compression by closing of the space and possible prevention of water fl ow. 3. hydrological characteristics the river gacka is characterized by favourable hydrological conditions. the fl ow regime is standardized in comparison to other karst rivers, and considerable alterations of the fl ow quantities through its river bed do not occur. the ratio of the lowest, medium, and highest discharge is 1:4:20, whereas the ratio of the neighboring lika river is 1:100:800 (bonac ci, 1987), which shows its vividly torrential character. the quantity of rainfall is one of the most important climatic factors with direct infl uence on the formation of underground and surface waters. although the entire lika region is characterized by a high quantity of rainfall, distinctive spatial differentiation in rainfall occurs. the areas with high relief (mountains) are characterized by greater rainfall than the lower areas (karst poljes). in the catchment areas of the spring zone of the river gacka and in its direct neighborhood, there are nine rain-gauge stations for measuring rainfall. on the basis of the collected hydrological data, the balance calculation was completed using the method based on quantity of runoff. the balance has been calculated both for the hydrological year 2002/2003 and for a period of thirty years. one hydrological year in the observed climate extends from the beginning of october to the end of september the next year. according to previous research, the surface of the gacka springs catchment area is 487 km2; 94% is underground runoff, and 6% is surface runoff. due to the signifi cant heterogeneity and unpredictability of karst systems, and a need for diffi cult and expensive research, together with the variations in size of the catchment depending on hydrological conditions, the defi ned catchment area can vary in size to a certain degree. in order to determine the average rainfall in the catchment area, a method based on isohyets was used. the isohyets were obtained by the interpolation of values of rainfall quantities in the observed hydrological year, reported by the 9 rain-gauge stations located in the catchment area and its neighbourhood (fig. 2). the quantity of annual rainfall for the hydrogeological year 2002/03 calculated according to this method was 924 mm. for the balance calculation, the value of the total catchment runoff was used, which was obtained by measurement of the daily discharge by the water-gauge station located about 8 km downstream from the spring zone. the supposition is that, along this fl ow, there are neither considerable infl ows nor runoffs. according to fi gu re 2: arrangement of isohyets in the catchment area of the spring zone of the gacka river. 1 – isohyet; 2 – groundwater divide; 3 – rain gauge station. geologia croatica 62/3geologia croatica 160 these data, the annual discharge for the observed hydrological year was 14.15 m3/s. the runoff coeffi cient is calculated according to the formula: α = q h avg (1) where α is the runoff coeffi cient, qavg is the runoff volume in m3, h is the rainfall volume in m3 over the catchment area in the observed hydrological year. the runoff coeffi cient, calculated according to the runoff quantity, is unnaturally high superfi cially. its value calculated according to this method is 0.99; thus, it implies that 99% of the total annual rainfall infi ltrates underground and that evapotranspiration almost does not exist. the runoff coeffi cient for the period of thirty years, calculated by the same method is 0.72, i.e. 72% of precipitation infi ltrates into the karst underground, from which it is apparent that the balance calculation for only one year does not produce relevant data. the main reason for such variation is masked by numerous infl uences, such as karstifi cation, cavity size, epikarst zone properties, air temperature, snow cover, terrain slope, and intraannual rainfall distribution. the quantities of rainfall have the greatest infl uence on the runoff quantities, and their annual collection is decisive if the rainfall quantities are considerably lower than the possible annual evapotranspiration. in this manner, from the example of the water-regime study of the karst spring situated in hungary, it was shown that for the same quantity of annual rainfall, underground infi ltration ranges from 7% to 70% (stepinac, 1969). because of the signifi cant heterogeneous characteristics of the karst aquifers, the quantitative data obtained either by pumping or by tracing refer to a narrow local area around the investigation site, and obtained values can rarely be average values that refer to the entire system (terzić et al., 2007, 2008). in contrast, the runoff hydrograms of springs refer to the total response of aquifers to rainfall (padilla et al., 1994). the recession diagram of gacka was prepared on the basis of the hydrogram of the discharge of the river gacka for the period from 01.02.2002. to 31.12.2003. from the runoff hydrogram, two recession periods can be identifi ed. the fi rst recession period extends from 15.04.2002. to 22.09.2002, and the second from 12.04.2003. to 20.10.2003. the drainage characteristics of the aquifer are better expressed in the second recession period, and this portion of the hydrogram is considered for the calculation of the recession coeffi cient (fig. 3) and runoff quantities from the water-bearing system. during the recession period, weaker rainfall was recorded. the hydrogeological year 2002/03 represented a dry year with reference to the previous ones, and hence it was suitable for observing the drainage characteristics of the water-bearing system. the springs are recharged by resources from the aquifer during the recession, which are accumulated in the hydrogeological basin during the recharging period. the shape of the curve depends on the hydrodynamic properties of the aquifers, such as hydraulic conductivity (k), storage coeffi cient (s), and hydraulic gradient (i), in addition to the geomorphological characteristics of the catchment area, such as geometry, slope, length, and karst-channel distribution. the following factors also have an important role: (a) season and climate, (b) the nature, thickness, spatial arrangement, and level of soil saturation. maillet’s formula (dewandela et al., 2003) is used for defi ning the recession component of the discharge hydrogram: qt=q0 x e–at (2) – where qt denotes the runoff quantity at a particular moment “t”, q0 is the runoff quantity at the beginning of recession, α is the recession coeffi cient, and “t” is the time. maillet’s exponential equation only approximately represents the analytical solution. there are other solutions that are used for defi ning the recession curve; these represent the exact analytical solutions from which it is possible to obtain the quantitative data of parameters of the water-bearing sysfi gu re 3: comparative presentation of the gacka river discharge, (semi-logarithmic scale) and the daily quantities of rainfall (lukač reberski, 2008). the period shown is from 27.01.2003. to 23.11.2003. lukač reberski et al.: an estimation of groundwater type and origin of the complex karst catchment... geologia croatica 161 tem. analyzing the particular segments of the curve between the 436th and 611th day, it is obvious that 18 days after the aquifer starts to empty changes in the conditions infl uencing runoff appear. this occurrence is apparent from the change of the slope direction by which the runoff curve is approximated after being transformed into the semilogarithmic scale, that is, from the change of the recession coeffi cient. in the beginning, the channels and larger joints are emptied, after which the smaller joints follow, which is shown in the milder slope of the curve. at the beginning of the recession, the slo pe of the curve is steep, with a calculated recession coeffi cient of α = 0.0323 day–1. then, a signifi cant curve slope change occurs with a recession coeffi cient of α = 0.0071 day–1, which indicates an aquifer of heterogeneous permeability, typical for karst aquifers. it was calculated that during the observed recession period that lasted 175 days, 99 x 106 cubic meters of water were discharged. 4. sampling, analysis methods, and data processing water samples were collected from 17 sites every month for one hydrogeological year, from september 2002 to september 2003 (table 1). the sampling locations comprised the upper fl ow region of the river gacka and its spring zone and boundary-catchment areas. toward the south of the river gacka, the catchment area of the river lika; to the northwest, the catchment area of the river korana; and to the south-east, the catchment area of the river una were also considered in this study. in the catchment area of the river gacka, the locations were springs tonkovića vrelo (7), majerovo vrelo (9), knjapovac (6), klanac (8), jaz (10), and pećina (5). in the catchment area of the river lika are the dežmino vrelo (1) and mlakvena greda (2) springs, and the krušćica accumulation (3). in the catchment area of the river korana, there are the springs of the crna (13) and bijela (14) rivers and the plitvica (15) and sartuk springs (17). the begovica (4) and pećina-korenica (11) springs are located in the catchment area of the river una. matica (12) belongs to the surface fl ow on a site where the bijela and crna streams join, and rodić (16) is on the confl uence of the plitvice and sartuk streams. some of these springs are temporary ones drying up in the summer months, when it is not possible to obtain samples. these are mlakvena greda, dežmino vrelo, and pećina-korenica (fig. 1). the values of water temperature, ph, electrolytic conductivity (ec value), and total dissolved solids (tds) were measured in situ. the analyses for determining the basic chemical parameters, such as alkalinity, calcium hardness, total hardness, nitrates, sulfates, and phosphates, were carried out in the laboratory. the processes of preparation and measurements of samples were the usual methods in hydrochemistry, and the chemicals used for sample preparations and standard solution were products of the hack company. ec and tds were measured by the wtw conductivity meter, model lf340/set, calibrated with a standard solution of 0.01 mol/l kcl. it is very important to determine the concentration of hydrogen ions because it is the most important parameter during calculation of the saturation (appelo & postma, 1994). moreover, it is best to measure the ph immediately in situ because, during the sampling for laboratory analyses, it is impossible to avoid the loss of carbon dioxide (co2) from water (gas removal), which leads to an increase in ph and sedimentation of caco3. thus, the results of the chemical analyses in the laboratory become erroneous. in addition, during sampling, the oxidation of some ions occurs, which can cause sedimentation of the mineral under study. the concentration of hydrogen ions and the temperature were measured by a 43800-00 model ph meter (hach). the instrument was calibrated in situ by applying standard buffer solutions of ph 7, 8, and 9. the instrument had a temperature compensator to avoid errors in ph measurements caused by the huge temperature difference between the spring and surface waters. alkalinity of the water samples was measured by titration with h2so4 using bromocresol greenmethyl red indicator. calcium and magnesium levels were determined by complexometric titration with edta, according to standardized procedures. the concentrations of sulfi des, nitrates, and phosphates were measured colorimetrically using a spectrophotometer (dr/2010, hach). all the afore-mentioned parameters were determined by the standard additive method, according to the procedures described in the instructions. the only variation was that the isotopic analyses of the stable isotopes δ18o and δ2h were carried out on 24 samples (table 2). the isotopic analyses were conducted in the “enviromental isotope laboratory”, institute of water resources management, graz, austria. for the year under study, the hydrological data were collected from the state hydrometeorological institute in order to correlate the hydrogeological and hydrogeochemical parameters. the computer program netpath (us geological survey, plummer et al., 1994), was used to model the geochemical reactions along a fl ow, and determine the balance of ions and the saturation state. it is evident from these calculations that particular minerals dissolve or are deposited under the conditions that dominate in the water medium. in this context, the saturation indices were calculated in relation to the minerals calcite (sic), aragonite (sia), and dolomite (sid); the partial pressure of co2 (pco2), and tds, and the concentrations of the main ions were calculated from the concentration unit mg/l by conversion into mol/l. multivariate cluster analysis was used to determine the extent to which the measured indicators of the hydrochemical system of the spring waters have similar affi nities, i.e. similar behaviour and origin. the cluster method aided interpretation of the geochemical data and served to strengthen the bonds between the samples (davis, 1986). its application has already shown its usefulness in the investigation of the morphometric and structural characteristics of water and soils in croatia (grgić, 1990; kapelj et al., 1999; peh & miko, 2003; marković et al., 2006). the basic principle of cluster analysis is the hierarchical arrangement of samples according to their similarity, i.e. the similarity of their attributes, into groups or clusters. most often they are the correlation coeffi cients. each hierarchical level within the dendrogram is a consequence of the degree of homogeneity within one group (cluster) and, therefore, the sample geologia croatica 62/3geologia croatica 162 table 1: results of measurements of hydrogeochemical indicators in spring and groundwater. location (number) – month – year t (°c) ec (µs/cm) ph ca2+ (mg/l) mg2+ (mg/l) na+ (mg/l) k+ (mg/l) hco3– (mg/l) cl– (mg/l) so4 2– (mg/l) no3 –n (mg/l) po4 3– (mg/l) mlakvena g. (2) -09-02 12.6 370 7.46 92 2.2 2.40 0.58 283 1.7 1 0.1 0.16 krušćica (3) -09-02 20.2 260 8.22 50 5.4 1.80 0.44 173 1.1 0.1 0.1 0.06 pećina (5) -09-02 9.6 328 7.72 87 3.9 1.90 0.12 269 1.1 2 1.0 0.06 knjapovac (6) -09-02 10.1 340 7.45 90 5 3.55 0.71 275 4.2 15 0.4 0.15 tonkovića v. (7) -09-02 9.9 338 7.4 89 5.9 3.72 0.88 271 3.2 15 0.3 0.12 klanac (8) -09-02 9.9 338 7.27 88 1.2 3.11 0.81 260 2.8 13 0.4 0.23 majerovo v. (9) -09-02 9.1 313 7.52 64 18 1.92 0.51 260 1.2 5 0.7 0.13 jaz (10) -09-02 10.1 340 7.41 89 5.4 3.44 0.67 277 4.0 15 0.3 0.11 dežmino v. (1) -10-02 9.7 358 6.91 100 3.2 2.21 0.49 323 1.8 1 0.2 0.14 mlakvena g. (2) -10-02 8.7 342 7.18 88 7.8 2.55 0.56 317 1.9 1 0.2 0.25 krušćica (3) -10-02 13.9 216 6.5 38 13 1.20 0.35 183 1.5 1 0.3 0.28 begovica (4) -10-02 9.3 333 6.97 70 16 1.28 0.51 295 0.3 1 0.5 0.33 pećina (5) -10-02 9.2 347 7.32 53 30 1.97 0.68 320 1.3 1 0.5 0.1 knjapovac (6) -10-02 9.9 354 7.37 45 36 2.58 0.71 314 1.3 9 0.5 0.19 tonkovića v. (7) -10-02 9.8 352 7.3 54 32 2.35 0.70 316 1.2 8 0.5 0.17 klanac (8) -10-02 9.4 339 7.39 47 34 2.41 0.83 308 1.5 5 0.6 0.17 majerovo v. (9) -10-02 8.9 317 7.44 67 20 1.68 0.43 291 1.2 1 0.6 0.19 jaz (10) -10-02 9.9 357 7.21 63 26 2.34 0.61 314 1.9 9 0.5 0.16 peć.-kor. (11) -10-02 9.4 327 6.91 52 26 1.30 0.21 287 1.0 1 0.4 0.18 dežmino v. (1) -11-02 9.3 363 7.32 78 1.2 1.50 0.38 253 1.1 0.1 0 0.01 mlakvena g. (2) -11-02 9.7 379 7.19 52 7.5 1.55 0.91 231 0.8 1 0.1 0.03 krušćica (3) -11-02 10.8 231 7.57 36 17 1.99 0.75 193 1.1 1 0.2 0.02 begovica (4) -11-02 9.1 327 6.77 51 9 1.02 0.33 205 0.5 0.1 0.3 0.12 pećina (5) -11-02 9.1 334 7.35 78 2 2.00 0.95 269 1.2 1 0.3 0.03 knjapovac (6) -11-02 9.8 374 7.25 57 18 1.85 0.90 270 1.0 1 0.4 0.07 tonkovića v. (7) -11-02 9.6 372 7.17 66 8.8 2.11 0.77 250 1.4 1 0.5 0.01 klanac (8) -11-02 9.2 334 7.24 71 1.5 2.07 0.81 240 1.2 1 0.3 0.01 majerovo v. (9) -11-02 8.7 323 7.27 77 1.9 3.20 0.97 256 1.6 1 0.5 0.03 jaz (10) -11-02 9.8 374 7.21 78 3.6 1.69 0.63 285 1.4 1 0.4 0.05 peć.-kor. (11) -11-02 8.9 331 6.95 57 3.1 2.05 0.58 194 1.1 1 0.3 0.08 matica (12) -11-02 7.8 298 7.39 54 19 1.50 0.44 265 0.7 0.1 0.7 0.05 crna (13) -11-02 7.6 277 7.59 66 7.1 1.61 0.32 238 0.4 0.1 0.5 0.02 bijela (14) -11-02 7.5 310 7.26 92 4.6 1.33 0.55 287 0.6 1 0.7 0.01 plitvica (15) -11-02 7.4 302 7.79 58 14 2.14 0.49 248 1.1 1 0.9 0.02 rodić (16) -11-02 7.4 303 7.6 63 11 2.25 0.72 251 1.1 1 0.8 0.01 sartuk (17) -11-02 8.2 312 7.35 73 7.1 2.35 0.67 261 1.1 1 0.9 0.05 dežmino v. (1) -12-02 9.2 353 7.3 95 0.2 1.57 0.42 291 0.9 1 0 0.01 mlakvena g. (2) -12-02 9.4 374 7.15 106 1.5 1.15 0.48 341 0.5 0.1 0 0.06 krušćica (3) -12-02 7.5 230 7.33 61 3.7 1.02 0.51 209 0.4 1 0.2 0.01 begovica (4) -12-02 9.1 329 6.87 96 6.8 2.09 1.00 314 1.1 1 0.3 0.19 pećina (5) -12-02 8.5 337 7.22 104 5.1 3.90 0.87 328 1.6 1 0.4 0.02 knjapovac (6) -12-02 9.5 364 7.27 104 5.4 4.10 0.88 331 2.0 1 0.3 0.04 tonkovića v. (7) -12-02 9.5 363 7.27 106 3.7 2.31 0.76 327 1.1 1 0.3 0.12 klanac (8) -12-02 9 334 7.4 98 5.1 2.22 0.80 311 1.1 1 0.4 0.02 majerovo v. (9) -12-02 8.7 321 7.27 89 6.8 2.90 0.85 292 1.5 0.1 0.6 0.04 jaz (10) -12-02 9.6 366 7.31 104 5.1 2.11 0.64 332 1.2 1 0.3 0.04 lukač reberski et al.: an estimation of groundwater type and origin of the complex karst catchment... geologia croatica 163 location (number) – month – year t (°c) ec (µs/cm) ph ca2+ (mg/l) mg2+ (mg/l) na+ (mg/l) k+ (mg/l) hco3– (mg/l) cl– (mg/l) so4 2– (mg/l) no3 –n (mg/l) po4 3– (mg/l) peć.-kor. (11) -12-02 7.7 305 6.75 84 7.3 2.44 0.68 292 1.4 1 0.3 0.03 dežmino v. (1) -01-03 9.4 343 7.35 99 4.6 1.20 0.34 315 0.8 0.1 0 <0.01 mlakvena g. (2) -01-03 7.1 317 7.72 99 0 1.35 0.40 294 1.2 0.1 0 <0.01 krušćica (3) -01-03 2.2 186 7.64 60 5.4 1.10 0.57 204 0.9 1 0 0.01 begovica (4) -01-03 9 326 7.08 91 0.5 1.40 0.52 269 0.7 0.1 0 0.14 pećina (5) -01-03 8.1 324 7.3 99 1 1.77 0.68 295 0.9 0.1 0 <0.01 knjapovac (6) -01-03 9.4 361 7.19 82 5.1 2.92 1.20 267 1.5 1 0 <0.01 tonkovića v. (7) -01-03 9.5 360 7.26 100 6.1 4.11 1.40 314 2.0 8 0 <0.01 klanac (8) -01-03 9.1 335 7.24 100 0.2 3.89 1.25 293 1.8 1 0 <0.01 majerovo v. (9) -01-03 8.6 311 7.76 104 2.9 4.03 0.98 311 2.0 7 0 <0.01 jaz (10) -01-03 9.4 362 7.26 98 0.5 2.51 0.52 301 1.2 8 0 <0.01 titpec-01-03 7.1 297 7.13 83 0.2 2.29 0.61 261 1.4 0.1 0 <0.01 dežmino v. (1) -02-03 10.4 325 7.57 90 5.1 1.22 0.38 307 0.7 3 0.1 0.01 mlakvena g. (2) -02-03 4.3 284 7.66 106 0.2 1.25 0.40 311 0.5 1 0.1 0.01 krušćica (3) -02-03 0.9 157 8.07 53 2.7 1.13 0.25 168 0.6 2 0.1 0.02 begovica (4) -02-03 8.9 261 7.41 93 0.2 1.08 0.26 272 0.4 1 0 0.13 pećina (5) -02-03 8 323 7.52 95 1.9 1.28 0.51 296 1.1 1 0 0.02 knjapovac (6) -02-03 9.4 360 7.3 104 2.2 1.97 0.68 316 1.1 1 0 0.04 tonkovića v. (7) -02-03 9.5 358 7.33 102 2.7 2.58 0.71 311 4.2 1 0 0.04 klanac (8) -02-03 9.1 338 7.32 96 3.4 2.35 0.70 297 3.2 1 0 0.04 majerovo v. (9) -02-03 8.7 313 7.33 83 7.3 2.41 0.83 279 2.8 1 0 0.04 jaz (10) -02-03 9.6 362 7.54 104 2.9 1.68 0.43 317 1.2 1 0.1 0.05 peć.-kor. (11) -02-03 5.2 280 7.77 85 5.6 2.34 0.61 276 4.0 0.1 0.1 0.04 matica (12) -02-03 6.5 284 8.36 57 26.6 1.30 0.21 297 1.8 1 0 0.05 crna (13) -02-03 7.8 276 7.66 67 11.5 1.50 0.38 249 1.9 0.1 0 0.06 bijela (14) -02-03 7.5 311 7.92 61 20 1.20 0.34 275 1.5 1 0 0.05 plitvica (15) -02-03 7.2 295 7.01 59 22.4 1.35 0.40 281 1.1 1 0 0.07 rodić (16) -02-03 5.7 282 7.83 61 21.5 1.10 0.57 280 1.1 1 0 0.04 sartuk (17) -02-03 3.3 265 7.49 58 25.4 1.40 0.52 291 1.5 0.1 0.1 0.03 dežmino v. (1) -03-03 10.1 335 7.3 93 3.4 1.77 0.68 287 1.2 3 0.2 0.01 mlakvena g. (2) -03-03 8 312 7.33 98 1.7 1.28 0.51 296 1.4 1 0.1 <0.01 krušćica (3) -03-03 5 196 7.89 59 3.4 1.97 0.68 187 0.8 1 0.3 <0.01 begovica (4) -03-03 6.7 286 7.21 89 1.2 2.58 0.71 266 1.2 0.1 0.4 0.15 pećina (5) -03-03 8.7 329 7.48 97 2 2.35 0.70 293 0.9 0.1 0.5 0.03 knjapovac (6) -03-03 9.5 358 7.28 101 3.9 3.56 1.10 303 1.6 10 0.4 0.01 tonkovića v. (7) -03-03 9.5 356 7.3 98 4.6 2.11 0.75 302 1.1 9 0.4 0.01 klanac (8) -03-03 9.1 331 7.48 95 3.4 1.69 0.63 295 1.5 0.1 0.4 0.02 majerovo v. (9) -03-03 8.6 309 7.25 84 4.9 2.05 0.58 268 2.0 0.1 0.6 0.01 jaz (10) -03-03 9.5 359 7.41 104 0 1.50 0.44 301 1.8 11 0.3 0.03 peć.-kor. (11) -03-03 8.9 313 7.53 89 1.22 1.61 0.32 266 2.0 1 0.4 0.01 matica (12) -03-03 7.9 289 8.26 64 18.1 1.33 0.55 275 1.2 0.1 0.8 0.03 crna (13) -03-03 7.7 279 7.77 67 11 2.14 0.49 248 4.0 0.1 0.6 0.06 bijela (14) -03-03 7.5 313 7.58 60 24.4 2.25 0.72 289 1.8 0.1 1.1. 0.05 plitvica (15) -03-03 7.2 284 7.65 62 19.5 2.35 0.67 269 1.9 1 1.3. 0.04 rodić (16) -03-03 7.6 287 7.24 61 20 1.57 0.42 271 1.5 1 1.3. 0.04 sartuk (17) -03-03 6 287 7.81 55 26.3 1.15 0.48 282 1.1 1 1.1. 0.02 table 1: continued geologia croatica 62/3geologia croatica 164 location (number) – month – year t (°c) ec (µs/cm) ph ca2+ (mg/l) mg2+ (mg/l) na+ (mg/l) k+ (mg/l) hco3– (mg/l) cl– (mg/l) so4 2– (mg/l) no3 –n (mg/l) po4 3– (mg/l) dežmino v. (1) -04-03 10.8 337 7.52 88 6.1 1.02 0.51 277 1.1 9 0.3 0.01 mlakvena g. (2) -04-03 10.3 363 7.31 93 0 2.09 1.00 270 1.5 1 0.2 0.01 krušćica (3) -04-03 12.3 234 7.36 55 5.6 1.35 0.40 187 1.2 0.1 0.3 0.01 begovica (4) -04-03 9.1 322 7.27 93 0 1.10 0.57 272 1.4 0.1 0.4 0.14 pećina (5) -04-03 9.1 336 6.63 98 0 1.40 0.52 285 0.8 0.1 0.6 0.01 knjapovac (6) -04-03 9.6 353 7.26 98 0 1.77 0.68 286 1.2 1 0.4 <0.01 tonkovića v. (7) -04-03 9.5 349 7.35 101 1.5 1.28 0.51 293 0.9 7 0.4 0.01 klanac (8) -04-03 9.6 332 7.63 94 2.7 1.97 0.68 287 0.7 0.1 0.4 0.01 majerovo v. (9) -04-03 8.7 306 7.22 84 6.6 2.58 0.71 275 0.9 0.1 0.6 0.02 jaz (10) -04-03 9.7 353 7.34 98 2.9 2.35 0.70 304 1.5 1 0.4 0.02 peć.-kor. (11) -04-03 9.6 310 7.43 87 3.9 2.41 0.83 278 2.0 1 0.3 0.02 matica (12) -04-03 9 300 8.19 62 17.8 1.68 0.43 270 1.8 0.1 0.8 0.02 crna (13) -04-03 7.7 276 7.83 68 10.2 2.34 0.61 247 2.0 0.1 0.6 0.02 bijela (14) -04-03 7.6 314 7.65 61 24.2 1.30 0.21 291 1.9 1 1.0 <0.01 plitvica (15) -04-03 7.6 286 7.86 60 19 1.28 0.51 263 1.0 0.1 1.4 0.01 rodić (16) -04-03 8 291 7.08 63 18.9 1.97 0.68 271 1.1 1 1.3 0.02 sartuk (17) -04-03 9.4 318 8.24 50 29 2.58 0.71 282 0.8 1 1.0 0.02 dežmino v. (1) -05-03 11 335 7.77 87 7.32 2.35 0.70 279 1.1 13 0.3 0.04 mlakvena g. (2) -05-03 13.3 377 7.23 92 3.4 2.41 0.83 281 0.5 4 0.1 0.02 krušćica (3) -05-03 20 272 8.07 50 6.8 1.68 0.43 181 1.2 1 0 0.12 begovica (4) -05-03 9.6 328 7.41 94 0.7 1.69 0.63 277 1.0 1 0.5 0.10 pećina (5) -05-03 9.3 328 7.42 92 3.2 2.05 0.58 280 1.4 1 0.9 0.01 knjapovac (6) -05-03 9.5 343 7.48 94 5.1 1.50 0.44 289 1.2 8 0.4 <0.01 tonkovića v. (7) -05-03 9.5 342 7.4 97 3.7 1.61 0.32 298 1.6 2 0.4 <0.01 klanac (8) -05-03 9.3 334 7.34 93 4.9 1.33 0.55 286 1.4 8 0.3 <0.01 majerovo v. (9) -05-03 8.9 308 7.24 78 11.5 2.14 0.49 281 1.1 1 0.7 0.13 jaz (10) -05-03 9.8 346 7.3 95 5.1 2.25 0.72 291 1.1 8 0.4 0.01 peć.-kor. (11) -05-03 10.7 312 7.71 79 9 2.35 0.67 273 1.5 1 0.3 <0.01 matica (12) -05-03 9.3 311 8.21 61 21 1.57 0.42 279 1.2 0.1 0.9 <0.01 crna (13) -05-03 7.9 281 7.54 65 14.6 1.15 0.48 259 1.4 0.1 0.7 <0.01 bijela (14) -05-03 7.5 310 7.47 60 27 1.69 0.63 301 0.8 1 1.2 0.14 plitvica (15) -05-03 7.3 301 7.99 63 21.2 2.05 0.58 282 1.2 1 1.3 <0.01 rodić (16) -05-03 8.7 310 8.27 65 22 1.50 0.44 290 0.9 1 1.2 0.01 sartuk (17) -05-03 9.9 321 8.49 65 21.7 1.61 0.32 290 0.7 1 1.1 <0.01 mlakvena g. (2) -06-03 20.1 422 7.53 98 1.5 1.33 0.55 293 0.9 1 0.1 0.05 krušćica (3) -06-03 26.5 272 8.27 45 5.4 2.14 0.49 162 1.5 1 0.2 0.01 begovica (4) -06-03 9.9 327 7.27 92 2.9 2.25 0.72 281 2.0 1 0.6 0.11 pećina (5) -06-03 9.7 318 7.46 85 3.4 2.35 0.67 261 1.8 1 0.8 0.05 knjapovac (6) -06-03 9.7 336 7.21 94 4.4 3.28 0.42 279 2.0 13 0.3 0.01 tonkovića v. (7) -06-03 9.8 335 7.25 94 4.4 1.15 0.48 278 1.9 14 0.5 0.01 klanac (8) -06-03 10.3 338 7.09 95 4.4 2.96 0.44 283 2.4 12 0.4 0.06 majerovo v. (9) -06-03 9.1 308 7.19 78 12 1.61 0.32 282 1.1 1 0.8 0.01 jaz (10) -06-03 9.9 338 7.46 96 4.9 3.59 0.81 286 1.9 14 0.5 0.01 matica (12) -06-03 10.6 322 8.16 55 31 2.14 0.49 309 1.1 1 0.7 0.01 crna (13) -06-03 7.9 279 7.57 62 17 2.25 0.72 261 0.5 1 0.5 0.01 bijela (14) -06-03 7.5 307 7.15 62 24 2.35 0.67 291 1.2 1 1.2 0.01 table 1: continued lukač reberski et al.: an estimation of groundwater type and origin of the complex karst catchment... geologia croatica 165 location (number) – month – year t (°c) ec (µs/cm) ph ca2+ (mg/l) mg2+ (mg/l) na+ (mg/l) k+ (mg/l) hco3– (mg/l) cl– (mg/l) so4 2– (mg/l) no3 –n (mg/l) po4 3– (mg/l) plitvica (15) -06-03 7.4 297 7.31 63 21 1.57 0.42 283 1.0 1 1 0.01 rodić (16) -06-03 10 315 7.71 59 22 2.58 0.71 275 1.4 1 1.2 0.01 sartuk (17) -06-03 14.7 353 8.16 52 25 2.35 0.70 270 1.2 1 1 0.01 dežmino v. (1) -07-03 11.3 366 8.11 90 6.8 4.21 0.83 276 2.1 16 0.4 0.01 krušćica (3) -07-03 25.8 318 8.7 43 8.3 1.68 0.43 164 1.4 1 0.2 0.04 begovica (4) -07-03 10.7 316 7.38 92 4.8 1.69 0.63 285 1.1 2 0.7 0.21 pećina (5) -07-03 9.4 315 8.11 87 6.3 2.05 0.58 279 1.1 1 1.2 0.02 knjapovac (6) -07-03 9.9 336 7.79 96 3.9 4.25 1.10 279 2.2 16 0.7 0.15 tonkovića v. (7) -07-03 9.8 335 7.57 97 6.3 1.61 0.32 293 1.2 15 0.6 0.01 klanac (8) -07-03 9.5 330 7.64 99 2.9 1.33 0.55 285 1.4 14 0.7 0.31 majerovo v. (9) -07-03 9 307 7.81 79 11 1.61 0.32 279 0.8 3 1 0.13 jaz (10) -07-03 10 339 7.76 98 4.9 2.32 0.79 290 2.0 16 0.6 0.03 matica (12) -07-03 11.8 329 8.91 55 28 2.14 0.49 293 0.9 2 0.9 0.06 crna (13) -07-03 7.9 280 8.28 63 22 2.25 0.72 283 0.7 3 0.9 0.06 bijela (14) -07-03 7.5 307 8.34 62 22 2.35 0.67 285 0.9 1 1.2 0.06 plitvica (15) -07-03 7.4 298 8.78 64 24 1.57 0.42 297 1.5 1 1.2 0.22 rodić (16) -07-03 8.7 306 9.02 60 23 2.58 0.71 282 2.0 1 1.3 0.05 sartuk (17) -07-03 13 342 9.14 51 25 2.35 0.70 264 1.8 2 1.2 0.01 krušćica (3) -08-03 24.2 272 8.56 44 6.3 2.41 0.83 160 2.0 1 0.5 0.16 begovica (4) -08-03 10.9 340 7.97 92 4.4 1.68 0.43 289 1.9 1 0.3 0.28 pećina (5) -08-03 10.3 315 8.41 87 11 1.69 0.63 307 1.0 1 0.5 0.07 knjapovac (6) -08-03 10.1 335 7.84 98 3.4 3.60 0.75 281 1.8 17 0.3 0.08 tonkovića v. (7) -08-03 9.8 330 7.7 94 4.4 4.20 0.33 273 2.3 18 0.3 0.01 klanac (8) -08-03 9.9 332 7.4 95 4.9 3.14 0.95 281 1.1 16 0.3 0.04 majerovo v. (9) -08-03 9.7 311 7.63 76 15 1.85 0.90 291 0.5 2 0.5 0.01 jaz (10) -08-03 10.1 337 8.06 96 4.9 3.11 0.82 281 2.1 18 0.4 0.06 matica (12) -08-03 9.6 310 9.17 62 22 2.07 0.81 285 1.0 2 0.7 0.02 crna (13) -08-03 7.9 280 8.74 67 14 1.99 0.75 264 1.4 1 0.4 0.03 bijela (14) -08-03 7.4 307 8.77 66 22 1.02 0.33 295 1.2 2 0.8 0.01 plitvica (15) -08-03 7.5 299 8.4 65 23 2.00 0.95 295 1.6 3 0.6 0.01 rodić (16) -08-03 9 305 8.83 60 25 1.85 0.90 293 1.4 2 0.5 0.05 sartuk (17) -08-03 14.2 346 9.07 52 30 2.15 0.71 290 3.0 4 0.8 0.06 krušćica (3) -09-03 17.6 229 8.62 49 8 2.07 0.81 183 2.8 1 0.2 0.01 begovica (4) -09-03 9.9 336 7.94 91 3.9 3.20 0.97 284 1.2 1 0.6 0.08 pećina (5) -09-03 9.3 332 8.11 76 3.4 2.25 0.72 233 4.0 2 0.9 0.07 knjapovac (6) -09-03 9.9 331 7.75 94 8.3 4.42 0.95 289 2.1 19 0.5 0.01 tonkovića v. (7) -09-03 9.9 332 7.83 92 12 4.35 0.79 301 2.0 19 0.6 0.01 klanac (8) -09-03 13.9 328 7.84 81 5.9 2.58 0.71 251 1.5 17 0.5 0.02 majerovo v. (9) -09-03 9.3 305 7.77 76 15 2.35 0.70 290 1.2 2 0.7 0.01 jaz (10) -09-03 10.1 336 7.92 94 12 3.58 0.91 305 2.8 21 0.5 0.01 matica (12) -09-03 9.6 308 8.21 66 22 1.68 0.43 296 1.3 2 0.8 0.01 crna (13) -09-03 7.8 282 8.21 68 18 1.69 0.63 284 1.0 1 0.6 0.08 bijela (14) -09-03 7.4 308 7.95 60 24 2.05 0.58 286 1.1 1 1 0.01 plitvica (15) -09-03 7.4 287 7.98 62 22 1.50 0.44 283 1.5 1 1.2 0.01 rodić (16) -09-03 8.1 290 8.76 65 20 1.61 0.32 282 1.2 1 1.2 0.08 sartuk (17) -09-03 9.5 304 9.01 63 21 1.33 0.55 281 1.4 1 1.1 0.01 table 1: continued geologia croatica 62/3geologia croatica 166 can only belong to one group. the coeffi cient of distance is the similarity measure, the values of which are between 0 and ∞. the value 0 represents total similarity. in processing the chosen data, pearson’s “r” distance was used, and ward’s method was applied for connecting the measured data,. ward’s method is based strictly on classifi cation demand, according to which data groups are formed such that the distance among particular members of the group is the least possible. 5. hydrogeochemical measurement results and their interpretation 5.1. temperature the temperature of groundwater is a well-known natural indicator, which serves to determine groundwater origin, underground retention time, and its dynamics. the water temperature at the spring is in accordance with the annual air temperature of the spring recharge area. consequently, the groundwater that is recharged from hypsometrically higher areas with lower annual average air temperatures will have a lower temperature. generally, the groundwater temperature in karst varies from 4.9 °c–17.8 °c (bonacci, 1987). in the karst areas where quick and turbulent groundwater fl ow prevails, the water temperature of a spring can be considerably infl uenced by seasonal changes of air temperature. during such quick groundwater fl ow, the retention time of the fresh infi ltrated water in the underground zone is short; hence, the annual oscillation of temperature in the spring will be greater. the temperature of the groundwater that fl ows near the surface varies considerably, in contrast to the fl ow in the deeper parts (gunn, 1982). water that sinks deep into the vadose zone and that is retained underground for a relatively long period has a homogeneous temperature with time. from the diagrams of temperature (fig. 4) measured in the springs, it can be observed that the greatest temperature alterations are noticed in the surface waters of the krušćica accumulation and in the mlakvena greda and sartuk springs. the krušćica accumulation is the surface fl ow of the lika river; mlakvena greda and sartuk have low diffuse dischar ge; in these places, the water temperature is under the infl uence of the air temperature. the least temperature variations are noted in the springs of the crna and bijela rivers (black and white rivers) and in the plitvica spring, all belonging to the catchment area of the korana. small variations are measured in the tonkovića vrelo, knjapovac, and jaz from the catchment area of the river gacka. this could be the result of homogenization of temperatures because of underground retention, i.e. because of the nonexistence of greater channel systems. the temperature variations are greater in the pećina spring, which is probably caused by the smaller surface of the catchment area of that spring. temperatures of the springs in the catchment area of the river gacka are somewhat higher (about 2 °c) than those in the catchment area of the river korana, which is in accordance with the average annual air temperature of the recharging area for these springs. 5.2. negative logarithm of the hydrogen ion concentrations (ph value) the activity of hydrogen ions in water solutions is controlled by the reactions in which the hydrogen ions are consumed or produced. it is very sensitive to weathering and mineral dissolution; however, as the concentration of the hydrogen ions is under the infl uence of numerous processes, it is diffi cult to attribute their values to different surroundings. the value of the ph of the spring waters is a useful indicator of the equilibrium reaction state. h+ ions are mostly obtained from h2co3, which is formed by the dissolution of co2 in water and is independent of other variables. therefore, hypotheses about the conditions in the catchment area are not proposed on the basis of h+ ions, but from the measured ph factor and alkalinity. the partial pressure of co2 (pco2) is calculated, on the basis of which conclusions are derived and hypotheses are proposed. according to the measured ph values, the spring waters of the investigated area are neutral to weakly alkaline. the lowest values of ph are predominantly found in the winter months, and they gradually increase during the warmer months (fig. 5). the highest values are achieved in summer. the smallest variations of ph are in the catchment area of the gacka river. in addition to the temperature variations, the values of ph, hydrogen carbonate alkalinity, and the basic ionic comtable 2: results of the measurements of stable isotopes. location (number) – month – year δ2h δ18o dežmino v. (1) -11-02 –53.6 –8.04 pećina (5) -11-02 –52.1 –7.91 tonkovića v. (7) -11-02 –59 –8.78 majerovo v. (9) -11-02 –63.5 –9.12 peć.-kor. (11) -11-02 –58 –8.83 plitvica (15) -11-02 –66.3 –9.85 dežmino v. (1) -01-03 –54.6 –8.46 pećina (5) -01-03 –55.7 –8.35 tonkovića v. (7) -11-02 –61 –8.93 majerovo v. (9) -01-03 –63.6 –9.53 peć.-kor. (11) -01-03 –63.7 –9.34 plitvica (15) -01-03 –71.8 –10.36 dežmino v. (1) -04-03 –60.2 –8.9 pećina (5) -04-03 –59.3 –8.64 tonkovića v. (7) -04-04 –60 –8.98 majerovo v. (9) -04-03 –65.9 –9.72 peć.-kor. (11) -04-03 –67 –9.74 plitvica (15) -04-03 –69.4 –10.49 dežmino v.(1) -07-03 –59.1 –8.86 pećina (5) -07-03 –57.4 –8.45 tonkovića v. (7) -07-04 –58.2 –8.81 majerovo v. (9) -07-03 –66.1 –9.89 peć.-kor. (11) -07-03 –64.1 –9.87 plitvica (15) -07-03 –69.6 –10.48 lukač reberski et al.: an estimation of groundwater type and origin of the complex karst catchment... geologia croatica 167 fi gu re 4: temperature of the spring and surface waters. fi gu re 5: variations of ph in spring and surface waters. geologia croatica 62/3geologia croatica 168 position in the spring and surface waters are the refl ections of the seasonal vegetation and hydrological conditions (appelo & postma, 1994; hem, 1985). in cases where there is strong mixing of each new contribution into the karst aquifer with the pre-existing groundwater, where the groundwater fl ow is predominantly diffuse, seasonal changes of temperature, ph, and tds are generally small. greater aberrations are present in springs where discharges oscillate considerably during the year (pavičić et al., 2003; dre ver, 1985). 5.3. partial pressure of carbon dioxide (pco2) atmospheric pco2 is constant – 10–3.5 atm (32 pa), i.e. 0.03 vol.% in the air; nevertheless, in the root zones where respiration processes occur, it varies depending on the depth and seasonal changes. at a depth of about 8–9 m, the value is increased 10 times (fig. 6, 7). the main source of co2 in soil is plant respiration or the oxidation of organic substances. agricultural soils have the highest content of co2. they are followed by grasslands and woodlands, the latter having the smallest co2 value. in open systems, in which a constant equilibrium of the pco2 of water with the atmospheric co2 is enabled, it remains constant, and the concentrations of carbonate and bicarbonate ions change according to the ph. in systems where carbonates prevail, such as in the catchment areas of the river gacka, the equations of the balanced reactions that occur in a water solution can serve as the basis for determining the formation of carbon dioxide. the ph and alkalinity are necessary for this calculation, and the value of initial pco2, e.g. from the air present in the soil, is obtained (hem, 1985). from the pco2 and ph values, in addition to the saturation state, it is possible to estimate the conditions in which the reactions took place. as the values fi gu re 6: seasonal alteration of pco2 in the soil in unsaturated medium (appelo & postma, 1994). fi gu re 7: values of the log pco2 on the observed sites. lukač reberski et al.: an estimation of groundwater type and origin of the complex karst catchment... geologia croatica 169 of pco2 are very small, it is usual to express them in the logarithmic scale. they are calculated using the neptah software package (plummer et al., 1994). the lowest values were obtained in the krušćica surface accumulation as expected, because near the surface, a constant equilibrium with atmospheric pco2 was enabled, which is considerably lower than the one in the soil, where the variations of these values are the greatest (fig. 7). low values were recorded in the springs in the catchment area of the river korana, and the reason was probably the deforestation of almost the entire catchment areas of these springs. the values of pco2 are highest in the winter months (fig. 7). they gradually decrease and reach the lowest values in summer. although the highest values of partial pressure are expected in summer because of the respiratory processes of plants, it does not occur, because rainfall is very rare in summer and there is no water that could bring co2 by infi ltration through the surface. the fi rst autumn rains bring the dissolved co2 from the root zone; hence, values are the highest in autumn. 5.4. electrical conductivity (ec) and total dissolved solids (tds) evaluation the ec value of pure water is low, but with the increase of tds in water, the conductivity increases. therefore, tds and ec are correlated. the values of ec in the springs knja po vac, tonkovića vrelo, and jaz from the catchment areas of the river gacke are almost identical: from september to november, they are increased, and thereafter they gradually decrease (fig. 8). after low water levels, heavy rains precipitate and wash out large quantities of dissolved substan ces from the soil and the epikarst zone, thus increasing the se le vels. in klanac, they are somewhat lower and uniform through out the year and in majerovo vrelo, they are even lower. in the catchment areas of the river korana, lower values were measured than in the catchment area of the gacka, most probably because of the lower average temperatures. in dilute solutions, a temperature increase of 1°c causes an increase in conductivity of about 2% (hem, 1985). another reason for the lower values of ec in the catchment area of the river korana could be the greater representation of dolomites in this catchment area, which are less soluble than limestones. the time needed to reach 95% saturation for dolomites is 100 times longer than that for limestones under similar conditions (appelo & postma, 1994). among all the spring zones that are under considerable infl uence of the surface (sartuk, mlakvena greda, dežmino vrelo, and the krušćica accumulation), the highest values were measured in august and the smallest in february. a similar situation occurs in the springs from the catchment area of the river una. in the winter months, the discharge is much greater, the dilutions are greater, and the ec is lower than in the summer periods. in the krušćica accumulation, fi gu re 8: the distribution of ec values. geologia croatica 62/3geologia croatica 170 the values are considerably lower and deviate from all other sampling locations, but this was expected because the surface water is diluted owing to the direct infl uence of rainfall. 5.5. alkalinity alkalinity of the water sample is equal to the number of equivalents of the dissociated weak acids; i.e. it represents the capacity of the dissolved substances in the solution to react with the acid and neutralize it. it is determined by titration with a strong acid, and the fi nal point is the ph at which all the dissolved substances that contribute to alkalinity begin to be reactive. although it is possible to fi nd other weak acids in the solution, in practice, only the dissolved carbonate acid has quantitative importance for determining the alkalinity. the alkalinity is equal to: alk m m hco co = +− − 3 3 22 (3) – where alk denotes the alkalinity expressed in the concentration unit, and m is the molar concentration [mmol/l]. at the values of ph < 8.3, less than 1% of carbonate acid is present as co3 2– and, in this situation, the concentrations of hydrogen and carbon are the only important ones. the main source of carbonate, which infl uences the alkalinity of the surface and underground waters, is co2 present in the atmosphere, in soil, and in the unsaturated medium. the carbonic acid is formed by dissolution of co2 in water, and it is separated into two stages in which the hydrogen carbonate and carbonate ions are formed, which is presented in the following reactions: co2(g) + h2o → h2co3 (4) h2co3 →h+ + hco3 – (5) hco3 – → h+ + co3 2– (6) the concentrations of the hydrogen carbonate ions in natural water range within a moderate interval because of the infl uence of the carbonate balance. most of the surface water bodies contain less than 200 mg/l hydrogen carbonate, where as in groundwater, somewhat higher values are usually present. the lowest concentrations of hydrogen carbonate ions were measured in november. the reason for this could be the greater dilution that occurs at the beginning of the rainy season (fig. 9). bunsen’s coeffi cient of co2 solubility is considerably greater at lower temperatures, and in accordance with this, the production of carbonic acid is greater, which dissociates to yield hydrogen carbonate ions. in the catchment area of the river gacka, there are greater differences between the minimum and the maximum values than in the catchment area of the river korana, probably because of the same reasons as in the case of homogenization of the temperature of the surface and underground waters. in the krušćica reservoir, the lowest values were recorded because of the direct exposure to rainfall and, hence, greater dilution of the constituents. fi gu re 9: hydrogen carbonate alkalinity of the springs and surface waters. lukač reberski et al.: an estimation of groundwater type and origin of the complex karst catchment... geologia croatica 171 fi gu re 10: distribution of calcium ions. fi gu re 11: distribution of magnesium ions. geologia croatica 62/3geologia croatica 172 5.6. calcium and magnesium the lowest values of ca concentrations were measured in october and november. in the catchment area of the river korana, the concentrations were considerably lower than in other catchments. in the krušćica surface accumulation, the lowest values were measured (fig. 10). in contrary to ca, the concentrations of mg ions were higher in october and november, after which period they decreased. the lowest values were measured in the winter months and, in the warm er summer months, they gradually increased (fig. 11). in the catchment area of the korana, they were considerably higher than in other catchment areas. as the carbonates are distinguished by their greater solubility in relation to other minerals, it can be expected that the basic anion and cation composition of water is a good refl ection of the environment through which the groundwater fl ows. from the molar ratio of magnesium and calcium (fig. 12), it is apparent that this ratio is considerably higher in the catchment area of korana than in other catchments, which indicates the aquifer being situated in rocks with a predominantly greater constituent of dolomites. moreover, the molar ratios of mg/ca measured in october was much higher than the ratios in other months because of the fi rst autumn rains, which wash out calcium, magnesium, and hydrogen carbonate ions from both the soil and the weathering zone in the surface parts of the area composed of dolomite-bearing rocks. this is also the explanation of the low values of calcium ions and high values of magnesium ions in october and november. during the warmer months in the majerovo vrelo, lowering of water levels, results in greater ratios of magnesium, which could indicate the presence of dolomites in the deeper parts of the aquifer. in other springs, this ratio is similar and indicates that these springs are recharged mostly from limestones. 5.7. saturation conditions with calcite and dolomite equilibrium is rare in nature. the solution is in most cases too saturated with reference to some minerals, which suggests the process of deposition; or it is unsaturated, which implies that dissolution of the mineral is in progress. the saturation index shows the direction in which the reaction takes place. the kinetics of carbonate dissolution are rapid enough to reach equilibrium in soils that contain fragments of caco3, and the circulation of air through the bare rock can be so rapid that the water entering the inner fi ssures of the rock mass is still unsaturated, which is necessary for calcite dissolution. to be able to calculate if the solution is in thermodynamic equilibrium, data about the activities of the various types of dissolved ions that represent a particular mi neral are necessary, in association with the temperature of the solution. the state of saturation is expressed by the ratio of the ionic activity products in the solution and the activity product in a state of equilibrium. very often, the saturation index is used, which is the logarithm of the above ratio (hem, 1985). si = log iap/k (7) – where si denotes the saturation index, iap denotes the product of ionic activity, and k is the product of solubility. if si = 0, it implies that an equilibrium exists between the mineral and the solution, si < 0 points to lack of saturafi gu re 12: molar ratios of mg/ca of the spring and surface waters. lukač reberski et al.: an estimation of groundwater type and origin of the complex karst catchment... geologia croatica 173 fi gu re 13: values of the saturation indexes for calcite (a) and dolomite (b). a b geologia croatica 62/3geologia croatica 174 tion, and si > 0 indicates the oversaturation of the solution with reference to the mineral. both saturation indices (for calcite and dolomite) indicate the lowest values in october, after which values increase to reach their maxima in the summer months (fig. 13). saturation indices in relation to calcite are approximately close to the equilibrium conditions of samples from the springs in the catchments of the rivers gacka and lika, whereas greater saturation was recorded in the summer months in samples from the springs of the catchments of the rivers korana and una. saturation with dolomi te ranges from the equilibrium state to the lack of saturation in the catchment areas of gacka and lika to oversaturation in the catchment areas of korana. the catchment of the river korana is composed predominantly of carbonates, in which dolomites prevail. in the catchments of the rivers gacka and lika, limestones prevail, which was confi rmed by the data obtained. 5.8. sulfates, nitrates, and phosphates spring waters in the lika region usually have low contents of sulfates. important sources of sulfates can be the melting of gypsum, oxidation of metal sulfi des (most often, pyrite), mixing of groundwater with seawater in some coastal zones (pavičić et al., 2006), acid rain, and fertilizers. sulfates can also be formed as a result of human infl uence such as pollution by wastewater; e.g., waters from cement factories or pollution caused by fuel burning. in all the springs from the gacka catchment, in dežmino vrelo from the catchment of the river lika, and in the begovica spring from the catchment of the river una, sulfates are present in considerably lower concentrations than in other samples. in the catchment area of the river korana, the values are low. the highest concentrations were measured in the summer months. in samples from the springs belonging to the catchment area of the rivers gacka and dežmino vrelo, the increased contents of sulfates probably originated from the factory manufacturing calcite products. nitrates in the groundwater can be of different origins, such as septic tanks, oxidation of organic nitrogen, and the growing problem of extensive usage of fertilizers in agriculture. the maximal permitted concentration (in croatia) of nitrates in water is 50 mg/l (which corresponds to 11 mg/l no3 –-n). phosphates are the only type of phosphorus complexes in the majority of water systems. they are good indicators of pollution because they are used in the production of detergents, and fertilizers and because they are present in faeces as the product of metabolic processes. the orthophosphate ion, po4 3,– is the fi nal product of dissociation of phos phoric acid. it represents the most stable form of phosphates and is often found in natural waters. the lowest values of nitrates were measured in the catchment areas of the river lika (< 0.4 mg/l), whereas in other places they were higher; however, they did not exceed 1.4 mg/l, which are very low values. orthophosphate ions range from < 0.1 to 0.31 mg /l po4 3–. regardless of the seasonal variations, the concentrations of phosphates and nitrates are generally very low (table 1), which indicates the superior quality of the groundwater. 5.9. statistical processing of the hydrogeochemical indicators statistical analysis using multivariate cluster analysis of r-modality, provided an insight into the mutual affi nity of the measured hydrogeochemical indicators in the spring waters. the chosen variables were sorted into three basic groups (fig. 14). two of them could be considered as lithogeochemical (c1 and c3), and one as human-induced (c2). c1 is named “limestone dissolution”, which implies karstifi cation. it is highlighted by three parameters (ca2+, hco3 –, and ec). the c2 cluster is most probably a consequence of road-salting during the winter time, and four indicators are emphasized (na+, k+, cl–, and so4 2–). this cluster is anthropogenic and is called the “human impact”. the c3 group is again lithogeochemical and based on mg2+ and no3 –-n levels. this cluster is most probably connected with the erosion and leaching of the soil and the epikarst belt, usually in the beginning of the rainy season. mg2+ ions are extracted in this group because of the weak solubility of the mineral dolomite in comparison with calcite. therefore, these ions are released from the rock fragments in the soil and the epikarst zone durfi gu re 14: dendrogram of the geochemical affi nities of the measured hydrogeochemical indicators. tree diagram, ward’s method, 1 – pearson r (statistica 7.0). lukač reberski et al.: an estimation of groundwater type and origin of the complex karst catchment... geologia croatica 175 ing the dry periods by vegetation, and then washed out by the fi rst rains. nitrates are also accumulated in the soil cover, mostly in karst poljes, and are also washed out by rainwater. 5.10. stable isotopes of oxygen (δ18o) and hydrogen (δ2h) stable hydrogen and oxygen isotopes are useful for establishing the origin of groundwater in areas where waters of diffrent origins, ages, and evolutions are present (guay at al., 2006). the ratio of these isotopes of oxygen and hydrogen is used in the investigation of karst hydrogeological systems to determine the recharge areas and for the investigation of the hydrodynamic conditions in aquifers. the oxygen and hydrogen isotopes are the components of the water molecule (hd16o, h2 16o, h2 18o), and in natural conditions, their concentrations vary from 180 to 340 ppm for deuterium (d) and from 1880 to 2010 ppm for 18o. the variations are the consequences of the so-called isotopic fractionation during the phase transitions of water. during evaporation, the lighter isotopes are separated, and the vapour becomes poor in heavy isotopes, in comparison with water. the fractionation depends on pressure, composition of steam, and the most important factor of all, the temperature of the phase transition. the lower the temperature of the phase transition is, the higher the fractioning effect, and vice versa. the isotopic composition of water is refl ected as the relative aberration (δ) of the ratio between the heavier isotopes and lighter ones in the sample (ruz) compared to the ratio of these isotopes in the standard (rstand), and it is expressed per thousand (δ x 1000): δ = −r r r uz s d s d tan tan (8) a sample of seawater obtained at a depth of 50 m in the ocean was used as the standard; ratio in standard mean oce an water (smow) for oxygen, rsmow = (2005.20 ± 0.45) x 10–6, and for deuterium, rsmow = (155.76 ± 0.05) x 10–6. there is a correlation between the quantities of the stable isotopes 18o and 2h in both rainfall and groundwater. at me etings of the international atomic energy agency (iaea) in vienna and the world meteorological organization (wmo), data were presented about the quantities of isotopes in rainfall as measured by the network of meteorological stations all over the world (iaea, 1981, 1983). linear dependence of the ratios of the isotopes δ18o and δ2h on rainfall can be represented by the equation of the line: δ2h = (8.17 ± 0.08) δ18o + (10.56 ± 0.64) ‰ (9) – with the correlation coeffi cient r = 0.997, and standard error of determination of δ2h = ± 3.35‰. the obtained line is called the “meteoric water line”. this line is valid for waters and rainfall that do not evaporate very much. the ratio of the stable isotopes in water samples is measured using the technique of mass spectrometry. in the chosen springs from which water was collected for the isotope analyses; (dežmino vrelo, pećina, tonkovića vrelo, majerovo vrelo, pećina-korenica, and plitvice), the infl uence of the high-altitude effect can be observed for all the periods of sample collection (autumn, winter, spring, and summer) (fig. 15). according to these data, the elevation above sea level of the predominant recharge of the plitvice spring is the highest, followed in order by the other springs: majerovo vrelo, pećina-korenica, tonkovića vrelo, dežmi no vrelo, and pećina. plitvica and majerovo vrelo partially drain the same area, although plitvica has more negative values be cause its catchment is at a higher elevation and further inland. the effect of seasons on the expected response in the springs under study is signifi cant. the values of the ratios are more positive in the autumn (november 2002) when the water is discharg ed, in which a part of the summer rainfall is expressed more, whereas in april, lower values of the ratio are noticed as a consequence of melting of snow, which is of greater infl uence than winter precipitation. clark & fritz (1997) estimated that the isotope gradient, also called the high-altitude effect, is about 0.15 to 0.5‰ for each 100-m increase in elevation above sea level for δ18o, and for deuterium, it is about –1 to –4‰ for the same gradient (in europe and africa). in the broader area of croatia, the gradient is between 0.26, for coastal station, to 0.37 ‰, for continental observation station (krajcar bronić et al., 2004; krajcar bronić et al., 2003). in accordance with this estimation, the elevations above sea level of the predominant recharge areas of the investigated springs were measured. the živulja spring, with a small catchment area and with constant discharge, was chosen as the referential source. however, the obtained values were too high for the plitvice spring; therefore, a reasonably greater gradient was used: 0.4‰/100-m elevation above sea level (fig. 16). in spite of the small number of data (only four samfi gu re 15: changes of the ratio of δ18o in samples of spring and surface waters. fi gu re 16: representation of elevations above sea level of the predominant recharge areas. geologia croatica 62/3geologia croatica 176 pl ing times per year), this can be explained by the fact that the recharge area of the plitvice spring in comparison with other springs is mostly under the infl uence of continental precipitation. 6. conclusion the investigation area is characterized by very poor surface hydrography, which is characteristic of all the karst areas. precipitation infi ltrates very quickly into the water table, and the springs are mostly situated in contact with the fault zones between the permeable and impermeable deposits. the rocks are mostly represented by carbonates (limestones and dolomites). structural-tectonic relationships are the main factors for creating the preferential groundwater-fl ow directions and the occurrence of springs (prelogović, 1989). the rockmass division was carried out according to their hydrogeological characteristics. the hinterland of the gacka spring zone is chiefl y composed of very permeable cretaceous limestones, palaeogene breccias (jelar), and impermeable dolomites, alternating with dolomitic limestone or dolomitic breccias to a certain extent. the jelar breccias are approximately 50% less permeable (bahun & fritz, 1975) than the jurassic and cretaceous carbonates. the jelar breccias are sorted into the less permeable deposits. complete barriers, incomplete barriers, and permeable areas can be distinguished based on the rock-mass characteristics. on the basis of the geological, structural-tectonic, hydrogeological, trac er, and hydrological data, the catchment area of the river gacka was defi ned as an area extending to 487 m2. the existing observation network of climatological, rain-gauge, and water-gauge stations in the entire catchment was not satisfactory. the processing of year-long series of hydrological data showed that calculating the balance for only one year does not yield relevant results for the runoff coeffi cients. the reason for this is the existence of the huge retention space (žugaj, 1981) in the hinterland of the spring zone, which enables the formation of vast water supplies that fl ow out in springs and recharge the fl ow of the river gacka during the drier period. this is also the reason for the homogenous fl ow of the river gacka in which there is no considerable change in the discharge even during years with the most extreme drought conditions. by analysis of the hydrograms of discharge and precipitation in the period from 01.02.2002. to 31.12.2003., the recession period was chosen, from which the recession coeffi cients and the approximate runoff quantities from the water-bearing system were calculated (fig. 3). the calculated recession coeffi cients led to the conclusion that this is a typical karst aquifer in which, after the period of rainfall, the channel systems and greater fracture zones (quick fl ow) are emptied fi rst and, subsequently, all smaller joints within the rock mass are emptied. finally, the shape of the curve increasingly suggests a similarity with the diffuse fl ow in an intergranular medium (basic fl ow). it was calculated that during the observed recession period that lasted 175 days, 99 x 106 cubic meters of water were discharged. this result corresponds to the analysis of the gacka river system made by žugaj (1981), according to which, the average volume of water fi lling and emptying from the underground retention zone was 103.2 x 106 m3. interpretation of the hydrogeochemical data and the statistical processing of fi eld and laboratory data, allowed the hydrogeochemical facies to be determined, and the results obtained aided decision making about both the origin of the groundwater and the characteristics of aquifers. statistical processing of the hydrochemical data using multivariate cluster analysis of r-modality, resulted in the chosen variables being grouped into three, which could be associated with the three most important processes in this sensitive karst system (fig. 14): (1) c1 is the group of all three indicators, two of which belong to limestone dissolution (ca2+ and hco3 –). the third indicator in c1 is ec, which practically indicates that karstifi cation has the greatest impact on ec, and therefore, on mine ralization of the tested water samples; (2) c2 is the human-induced factor, or pollution, which mostly originates from the salt used for melting the ice from roads and motorways within the catchment area; and (3) c3 is again a natural lithogeochemical factor, associated with the washing out of the soil and the epikarst zone; nevertheless, the interpretation level is less clear than from the fi rst two clusters, because it has only two parameters (mg2+ and no3 –). compounds that are washed out by the fi rst heavy rains in the beginning of the rainy season are natural (mg2+, from dolomite rock fragments) or nitrogen transformation (no3 –, nitrifi cation caused by agriculture and plantrespiration processes). hydrochemical analyses identifi ed characteristics of particular springs and their mutual similarities and differences. in the springs from the korana catchment, the ratios of mg and ca ions are considerably higher than in the springs of other catchments, which suggests that the aquifer is situated predominantly in the midst of dolomites. in the catchment of the river gacka on majerovo vrelo, greater concentrations of mg ions were measured than in other gacka springs. it appears that the recharge area of this part of the catchment is characterized by dolomites in the deeper zones of the karst aquifer. the nitrate and phosphate concentrations are very low, which shows the superior quality of groundwater. the ratios of the stable isotopes of oxygen and hydrogen enabled the determination of the average elevation of the recharge areas of particular springs. on the basis of these data, it was concluded that the recharge area of the plitvice spring has the highest elevation. it is followed by majerovo vrelo, pećina-korenica, tonkovića vrelo, dežmino vrelo, and pećina, in order of decreasing elevation (fig. 16). for more precise results, the sampling should be undertaken more often. these results were obtained on the basis of only four samplings during the observed hydrological year, in which rainy and snowy months prevailed, and at these times, the precipitation was enriched with the lighter isotopes. a multidisciplinary approach, with a special reference to hydrogeochemical and isotopic data, allowed a better understanding of this complex karst system and its catchment boundaries. lukač reberski et al.: an estimation of groundwater type and origin of the complex karst catchment... geologia croatica 177 acknowledgement this research was carried out within the framework of the research project of the croatian ministry of science, education and sports: ‘basic hydrogeological map of croatia’ project no. 181-1811096-3165. references appelo, c.a.j & postma, d. (1994): geochemistry, groundwater and pollution. balkema, rotterdam, 536 p. azzaz, h., cherchali, m., meddi, m., houha, b., puig, j.m. & achachi, a. (2008): the use of environmental isotopic and hydrochemical tracers to characterize the functioning of karst systems in the tlemcen mountains, northwest algeria.– hydrogeol. j., 16, 531–546. doi: 10.1007/s10040-007-0235-4 bahun, s. & fritz, f. (1975): hidrogeološke specifi čnosti jelarnaslaga [hydrogeological specifi cities of the jelar breccias – in cro atian]. geol. vjesnik, 28, 345–355. bonacci, o. (1987): karst hydrology with special reference to the dinaric karst. springer-verlag-berlin-heidelberg, 9/4, 328–338. bonacci, o. (2001): analysis of the maximum discharge of karst springs.– hydrogeol., j., 9, 328–338. doi: 10.1007/s100400100142 bonacci, o. & andrić, i. (2008): sinking karst rivers hydrology: case of the lika and gacka (croatia).– acta carstologica, postojna, 37/2–3, 185–196. clark, i. & fritz, p. (1997) environmental isotopes in hydrogeology. lewis, 328 p. davis, j.c. (1986) statistics and data analysis in geology. ii ed. john wiley and sons, new york, 646 p. dewandela, b., lachassagneb, p., bakalowicz, m., wengb, p. & al-malki, a. (2003): evaluation of aquifer thickness by analysing recession hydrographs. application to the evaluation oman ophiolite hard-rock aquifer.– j. hydrol., 274, 248–269. doi:10.1016/s0022-1694(02)00418-3 drever, j.i. (1985): the geochemistry of natural waters. prentice hall inc., englewood cliffs, 436 p. gottstein matočec, s., bakran-petricioli, t., bedek, j., bukovec, d., buzjak, s., franičević, m., jalžić, b., kerovec, m., kletečki, e., kralj, j., kružić, p., kučinić, m., kuhta, m., matočec, n., ozimec, r., rađa, t., štamol, v., ternjej, i. & tvrtković, n. (2002): an overview of the cave and interstitial biota of croatia.– natura croatica, 11/1, 1–112. grgić, s. (1990): utjecaj agrotehničkih kemijskih sredstava na sadržaj teških metala u podzemnim vodama i tlu na području istočne slavonije [infl uence of the agrotechnic chemicals on heavy metal compound in groundwater and soil of eastern slavonia – in croatian].– unpubl. master’s thesis. university of zagreb, 148 p. guay, b.e., eastoe, c.j., basset, r. & long, a. (2006): identifying sources of groundwater in the lower colorado river valley, usa, with δ18o, δd, and 3h: implications for river water accounting.– hydrogeol. j., 14,146–158. gunn, j. (1982): point – recharge of limestone aquifers – a model from new zeland karst.– j. hydrol., 61, 19–29. hem, j.d. (1985): study and interpretation of the chemical characteristics of natural water. u.s.g.s. water supply paper, 2254, 263 p. horvatinčić, n., krajcar bronić, i., prezdič, j., srdoč, d. & obelić, b. (1986): the distribution of radioactive 3h, 14c and stable 2h, 18o isotopes in precipitation, surface and groundwaters.– nucl. instrum. methods, b 17, 550–553. iaea (1981): stable isotope hydrology. tehnical report series no. 210, vienna, 339 p. iaea (1983): guidebook on nuclear techniques in hydrology, technical report series no. 91, international atomic energy agency, vienna, 439 p. kapelj, j., kapelj, s. & miko, s. (1999): pristup istraživanju utjecaja poljoprivrede na krški izvor [an approach to the researching of the infl uence of agriculture on karst springs – in croatian]. 2. hrvatska konferencija o vodama (2nd croatian water conference), dubrovnik, proc., 901–907. krajcar bronić, i., horvatinčić, n., barešić, j., obelić, b. & vreča, p. (2004): isotope composition of precipitation in croatia: comparison of continental and maritime stations. proceedings of the international workshop on the application of isotope techniques in hydrological and environmental studies. unesco, paris, france, september 6–8, 2004. krajcar bronić, i., horvatinčić, n., barešić, j., obelić, b., vreča, p., lojen, s. & vidič, s. (2003): isotope composition of precipitation in croatia and slovenia: basic data for groundwater studies.– rmz – materials and geoenvironmet, groundwater in geological engineering, ljubljana, 50/1, 173–176. lukač reberski, j. (2008): hidrogeološka i hidrogeokemijska osnova za defi niranje slijeva gacke i zaštita njenog izvorišta [hydro geological and hydrogeochemical basis for the catchment area defi nition: a gacka river springs catchment area – in cro atian].– unpubl. master’s thesis. rudarsko-geološko-naftni fakultet, sveučilište u zagrebu (faculty of mining, geology and petroleum engineering, university of zagreb), 118 p. marković, t., miko, s., kapelj, s., buljan, r., larva, o. & peh, z. (2006): behaviour of metals and nutrients in soils and groundwater of a karst polje.– j. geochem. explor., 88/3, 124–129. doi:10.1016/j.gexplo.2005.08.024 pavičić, a., kapelj, s. & lukač, j. (2003): the infl uence of the highway on the protected spring of gacka river. rmz – materials and geoenvironment 50/1, 289–292. pavičić, a., terzić, j. & berović, n. (2006): hydrogeological relations of the golubinka karst spring in ljubač bay, dalmatia, croatia.– geol. croat., 59, 123–135. padilla, a., pulido-bosch, a. & mangin, a. (1994): relative importance of basefl ow and quickfl ow from hydrographs of karst spring.– ground water, 32/2, 267–277. peh, z. & miko, s. (2003): impact of geomorphological variables in weighing the lithological infl uence on geochemical composition of stream and overbank sediments: a regression model for the žimberak area (nw croatia). geol. croat., 56/2, 199–214. plummer, l.n., prestemon, e.c. & parkhurst, d.l. (1994): an interactive code (netpath) for modelling net geochemical reactions alog a fl ow path, version 2.0, usgs; water-resources investigations report 94–4169, reston, virginia. prelogović, e. (1989): neotektonski pokreti u području sjevernog velebita i dijela like [neotectonic movements in northern velebit and part of lika – in croatian]. geol. vjesnik, 42, 133–147. simsek, c., elci, a., gunduz, o. & erdogan, b. (2008): hydrogeological and hydrogeochemical characterization of a karstic mountain region.– environ. geol., 54, 291–308. stepinac, a. (1969): otjecanje u dinarskom kršu [runoff in the dinaric karst – in croatian].– krš jugoslavije, zagreb, 6, 207–235. terzić, j., šumanovac, f. & buljan, r. (2007): an assessment of hydrogeological parameters on the karstic island of dugi otok, croatia.– j. hydrol., 343/1–2, 29–42. doi: 10.1016/j.hydrol.2007. 06.008 terzić, j., marković, t. & pekaš, ž. (2008): infl uence of sea water intrusion and agricultural production on the blato aquifer, island of korčula, croatia.– environ. geol., 54/4, 719–729. doi: 10.1007/ s00254-007-0841-4 geologia croatica 62/3geologia croatica 178 velić, i. (2007): stratigraphy and palaeobiogeography of mesozoic benthic foraminifera of the karst dinarides – se europe.– geol. croat., 60/1, 1–114. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005) evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeogr. palaeocl., 220, 333–360. žugaj, m. (1981): posebne analize u hidrotehnici [special analyses in hydrotechnics – in croatian].– monography. građevinski institut, sveučilišna naklada liber, zagreb, 140 p. manuscript received june 19, 2009 revised manuscript accepted september 28, 2009 available online october 30, 2009 boukhary-370.indd 19 � mohamed boukhary1, abdel-mohsen m. morsi1, ragy eissa2 and moustafa kerdany3 ab stra ct ostracod faunas from an exposure of the cenomanian galala formation in the area south of ain sukhna on the western side of the gulf of suez have yielded 11 species belonging to 10 genera. the recorded speciesare have been taxonomically described, discussed where required, and illustrated. the ostracod assemblage is characteristic for the late cenomanian. it is composed of taxa of a typical marine shelf setting. the majority of the recorded species have a vastly extended geographic distribution in the areas along the southern shores of tethys, indicating the absence of signifi cant geographic barriers along this stretch during the late cenomanian. keywords: ostracods, late cenomanian, southern tethys, egypt 1 geology department, faculty of science, ain shams university, 11566 cairo, egypt; (moboukhary@yahoo.com; ammorsi@hotmail.com) 2 nozha street 107, triumph, heliopolis, cairo, egypt 3 160 street 2, maadi, cairo, egypt; (mokerdany@gawab.com) late cenomanian ostracod faunas from the area south of ain sukhna, western side of the gulf of suez, egypt geologia croatica 62/1 19–30 3 figs. 2 tabs. 2 pls. zagreb 2009 geologia croaticageologia croatica � 1. introduction the studied section is located on the western side of the gulf of suez, 5 km south of ain sukhna at latitude 29°33´17˝ and longitude 32°20´24˝ (fig. 1). it consists of yellowish and grayish calcareous marls assigned to the cenomanian galala formation (fig. 2). it is underlain by a covered interval resting upon a ~70 m thick succession of varicoloured sandstones with minor clay, marl and limestone interbeds of the permo-triassic qiseib formation of abdallah & adindani (1963). it is overlain by ~100 m of intercalated limestones and dolomites assigned by kerdany et al. (1973) to the senonian, followed by eocene limestones. a well-preserved ostracod fauna has been retrieved from the galala formation. the investigated section was previously studied for foraminifers (kerdany et al., 1973) and ostracods (boukhary et al., 1977). re-investigation of the present section for ostracods yielded an additional faunal record which has not been documented in the previous study. the recorded fauna has been classifi ed following updated taxonomy. furthermore, it has been studied for biostratigraphic as well as palaeobiogeographic aspects. the number of previous studies dealing with the cenomanian ostracods of egypt has been substantially increased and many publications are now available. signifi cant papers are those by bold (1964), colin & el dakkak (1975), boukhary et al. (1977), hataba & ammar (1990), shahin (1991), shahin & kora (1991), orabi & ismail (1993), shahin et al. (1994), ismail (1999), szczechura et al. (1991), ismail & soliman (1997), ismail (1999, 2001), morsi & bauer (2001) and bassiouni (2002). since egypt was a part of the south tethyan palaeobiogeographic province during the cenomanian, studies dealing with other areas in north africa and the middle east are equally important. the publications of bassoullet & damotte (1969), damotte & saintmarc (1972), grosdidier (1973), rosenfeld & raab (1974), gerry & rosenfeld (1973), al-abdul-razzaq (1979), ben youssef (1980), al-abdul-razzaq & grosdidier (1981), bismuth et al., (1981a, b), al-furaih (1983), gargouri-razgallah, 1983), babinot (1985), babinot & basha (1985), geologia croatica geologia croatica 62/1 20 damotte (1985, 1995), viviére (1985), athersuch (1988, 1994), babinot & colin (1988), majoran (1988, 1989, 1996), andreu-boussut (1991), andreu (1993), abdallah et al. (1995), gebhardt (1999), colin et al. (2001), luger (2003) and schulze et al. (2004) have also been used here. 2. systematic descriptions the studied faunas yielded 11 ostracod species belonging to 10 genera (table 1). the classifi cation used here is that adopted in horn et al. (2002). morphological and taxonomic remarks have been given to previously known species wherever necessary. reference numbers (ac–01 to ac–29) are given only to the illustrated specimens. they have been photographed using the cam scan sem of bremen university, germany, and are permanently stored at the geology department, faculty of science, ain shams university (cairo, egypt). class ostracoda latrielle, 1806 subclass podocopa müller, 1894 order platycopida sars, 1866 suborder platycopina sars, 1866 superfamily cytherelloidea sars, 1866 family cytherellidae sars, 1866 genus cytherella jones, 1849 type species: cytherina ovata roemer, 1840 cytherella aegyptiensis colin & el dakkak, 1975 (pl. 1, figs. 1–2) 1974 cytherella gr. ovata (roemer) – rosenfeld & raab, p. 3, pl. 1, fi gs. 3–5 1975 cytherella aegyptiensis n.sp. – colin & el dakkak, p. 50, pl. 1, fi gs. 2–3 1977 cytherella ovata (roemer) – boukhary et al., p. 156, pl. 1, fi g. 10a–b 1991 cytherella cf. eosulcata colin – shahin, p. 133, pl. 1, fi gs. 3–4 1991 cytherella aegyptiensis colin & el dakkak – szczechura et al., p. 12, pl. 1, fi gs. 1–6 fi gu re 1: location map of the studied section. fi gu re 2: stratigraphic log of the studied section. table 1: stratigraphic distribution of ostracods in the studied section. a ge fo rm at io n sa m pl es pa ra cy pr is du be rt re ti n eo cy th er e? m ac ke nz ie i ve en ia cy th er ei s s tr eb lo lo ph at a sc hi st a pe lo rio ps p us tu la ta d ol oc yt he rid ea a tla st ic a m et ac yt he ro pt er on b er be ric um cy th er ei s n am ou se ns is cy th er el la a eg yp tie ns is eo cy th er op te ro n? c f. pu nc ta ta pe lo rio ps a eg yp tia ca g en . i nd et . s p. la te c en om an ia n g al al a fm . s–04 • • • s–03 • • • • • • • • s–02 • • • • • • • • • s–01 • • • • • • • geologia croaticaboukhary et al.: late cenomanian ostracod faunas from the area south of ain sukhna, western side of the gulf of suez, egypt 21 1994 cytherella ahmadiensis al-abdul-razzaq – shahin et al., p. 36, pl. 1, fi gs. 1–2 2001 cytherella aegyptiensis colin & el dakkak – morsi & bauer, p. 383, pl. 1, fi gs. 1–2 material: 11 specimens. dimensions: length: 0.92–0.96 mm; height: 0.59–0.61 mm; width: 0.51–0.53 mm. stratigraphic and geographic distribution: this species is known from the cenomanian of egypt (colin & el dakkak, 1975; boukhary et al., 1977; shahin et al., 1994; morsi & bauer, 2001; szczechura et al., 1991), lower cenomanian of jordan (babinot & basha, 1985) and the cenomanian–turonian of israel (rosenfeld & raab, 1974). in the studied section, it occurs in the upper cenomanian, samples s–02 and s–03. order podocopida müller, 1894 suborder cypridocopina jones, 1901 superfamily cypridoidea baird, 1845 family candonidae kaufmann, 1900 genus paracypris sars, 1923 type species: paracypris polita sars, 1866 paracypris dubertreti damotte & saint-marc, 1972 (pl. 1, figs. 3–4) 1972 paracypris dubertreti n.sp. – damotte & saint-marc, p. 276, pl. 1, fi g.1 1974 paracypris acutocaudata n.sp. rosenfeld in rosenfeld & raab, p. 8, pl. 1, fi gs. 22–24 1977 paracypris acutocaudata rosenfeld – boukhary et al., p. 157, pl. 1, fi gs. 8a–c, 9a–c 1984 paracypris acutocaudata rosenfeld – rosenfeld & raab, p. 116 1985 paracypris dubertreti damotte & saint-marc – viviere, p.149, pl. 3, fi gs. 6–7 1989 paracypris dubertreti? damotte & saint-marc – majoran, p.10, pl. 2, fi gs. 10–12 1994 paracypris acutocaudata rosenfeld – shahin et al., p. 41, pl. 1, fi g. 23 1999 paracypris acuta (cornuel) – ismail, p. 309, pl. 3, fi gs. 14–15 1999 paracypris acutocaudata rosenfeld – ismail, p. 310, pl. 3, fi gs. 16–17 2001 paracypris dubertreti damotte & saint-marc – morsi & bauer, p. 385, pl. 2, fi gs. 4–5 2001 paracypris dubertreti damotte & saint-marc – hewaidy & morsi, p. 239, pl. 2, fi g. 6. 2002 paracypris dubertreti damotte & saint-marc – bassiouni, p. 19, pl. 2, fi gs. 5–9 material: 3 specimens. dimensions: length: 0.72–0.74 mm; height: 0.26–0.27 mm. stratigraphic and geographic distribution: this species was fi rst described from the middle and upper cenomanian of lebanon (damotte & saint-marc, 1972), aptian to upper cenomanian of israel (rosenfeld & raab, 1974, 1984), cenomanian of algeria (majoran, 1989) and jordan (schulze et al., 2004), cenomanian–lower turonian of algeria (viviére, 1985) and aptian–albian and cenomanian of egypt (boukhary et al., 1977; shahin et al., 1994; ismail, 1999, morsi & bauer, 2001; hewaidy & morsi, 2001; bassiouni, 2002). here, it occurs in the upper cenomanian, samples s–01 and s–02. superfamily cytheroidea baird, 1850 family cytherideidae sars, 1925 subfamily cytherideinae sars, 1925 genus dolocytheridea triebel, 1938 type species: cytherina hilseana roemer, 1841 dolocytheridea atlasica bassoullet & damotte, 1969 (pl. 1, figs. 5–8) 1969 dolocytheridea atlasica n.sp. bassoullet & damotte, p. 139, pl. 2, fi gs. 9a–d 1973 dolocytheridea cf. atlasica bassoullet & damotte – grosdidier, pl. 3, fi g. 22 1974 dolocytheridea atlasica bassoullet & damotte – rosenfeld & raab, p. 11, pl. 2, fi gs. 12–13 1975 dolocytheridea (puracytheridea?) atlasica bassoullet & damotte – colin & el dakkak, p. 57, pl. 2, fi g. 3 1977 dolocytheridea atlasica bassoullet & damotte – boukhary et al., p. 157, pl. 1, fi g. 11 1980 dolocytheridea atlasica bassoullet & damotte – ben youssef, p. 91, pl. 5, fi gs. 12–13; pl. 6, fi g. 19 ?1981a parakrithe sp. – bismuth et al., p. 230, fi g. 6 ?1983 schuleridea sp. – gargouri-razgallah, p. 185, pl. 31, fi g. 10 1985 dolocytheridea aff. atlasica bassoullet & damotte – viviére, p. 154, pl. 4, fi gs. 1–2 ?1989 ‘dolocytheridea’ polymorphica n.sp. – majoran, p. 11, pl. 3, fi gs. 10–13 1991 dolocytheridea? sp. 4 – andreu-boussut, p. 508, pl. 16, fi gs. 1–3 1991 dolocytheridea atlasica bassoullet & damotte – szczechura et al., p. 16, pl. 3, fi gs. 1–10 ?1991 dolocytheridea? atlasica bassoullet & damotte – szczechura et al., pl. 3, fi g. 11 1994 dolocytheridea atlasica bassoullet & damotte – shahin et al., p. 47, pl. 2, fi gs. 14–15 2001 dolocytheridea atlasica bassoullet & damotte – colin et al., p. 94, pl. 1, fi gs. 7–8 2001 dolocytheridea atlasica bassoullet & damotte – ismail, fi g. 12: 4–6. 2001 dolocytheridea atlasica bassoullet & damotte – morsi & bauer, p. 387, pl. 2, fi g. 14. 2002 dolocytheridea atlasica bassoullet & damotte – bassiouni, p. 25, pl. 4, fi gs. 12–16 material: 44 specimens. dimensions: length: 0.68–0.76 mm; height: 0.37–0.43 mm; width: 0.37–0.40 mm. remarks: the descriptions and illustrations of the pre sent species in the above mentioned citations show variations in the degree of angularity at the posteroventral corner, which are considered conspecifi c. these variations are observed in the present material and have been also noted by majoran (1989) and bassiouni (2002), and discussed by bassiouni (op. cit.). as bassiouni remarked, variations in the size of the present species are also present in the different areas. the size range of our material is comparable with that recorded by colin & el dakkak (1975) and bassiouni (2002) and relatively larger than in the other records listed in the synonymy. geologia croatica geologia croatica 62/1 22 stratigraphic and geographic distribution: dolocytheridea atlasica is widely known from the lower and upper cenomanian of algeria (bassoullet & damotte, 1969; viviére, 1985; majoran, 1989), lower and upper cenomanian of israel (rosenfeld & raab, 1974), cenomanian of morocco (andreu-boussut, 1991; andreu, 1993), tunisia (ben youssef, 1980; bismuth et al., 1981a; gargouri-razgallah, 1983) and jordan (babinot & basha, 1985; schulze et al., 2004) and upper albian to cenomanian of oman (babinot & boulardillon de grissac, 1989; colin et al., 2001) and iran (grosdidier, 1973). it was also recorded in the upper albian–cenomanian of iraq (riche & pristat, 1980) and the cenomanian of libya and somalia (colin et al, 2001). in egypt, it is recorded from the (?) late albian– turonian (shahin et al., 1994; colin & el dakkak, 1975; boukhary et al., 1977; szczechura, et al., 1991; ismail, 2001; morsi & bauer, 2001; bassiouni, 2002). in the present study, this species occurs in the upper cenomanian, samples s–01, s–02, s–03 and s–04. family cytheruridae müller, 1894 genus eocytheropteron alexander, 1933 type species: cytheropteron bilobatum alexander, 1929 eocytheropteron? cf. punctata (bassiouni, 2002) (pl. 1, figs. 9–12) 1977 aversovalva sp. boukhary et al., p. 158, pl. 1, fi g. 5a–b cf. 2002 majungaella hevyonensis punctata n.sp. bassiouni, p. 61, pl. 13, fi gs. 6–10 material: 5 specimens. dimensions: length: 0.43–0.45 mm; height: 0.25–0.26 mm; width: 0.26 mm. remarks: the present species is assigned to the genus eocytheropteron alexander, 1933 as it resembles other known species belonging to this genus in having similar lateral and dorsal outlines, a posteriodorsal caudal process as well as a ventrolateral extension overreaching the ventral margin. however, this assignment is made questionable since no open valves have been found and the internal features could not hence be investigated. the species to which our material has been conferred was erected by bassiouni (2002) as a new subspecies of neocythere? hevyonensis rosenfeld & raab, 1974, from the early cenomanian of egypt, being both assigned to the genus majungaella grékoff, 1963. the assignment of eocytheropteron? punctata to this genus is questionable since no open valves were described for this species and as majungaella is known more for the southern gondwana. the present material deviates from e.? punctata in having a broader, less protruding posterior caudal process. eocytheropteron retroversicardinatum al-abdulrazzaq, 1980, from the early cenomanian of kuwait is punctate like the present specimens and eocytheropteron? punctata, but has a different lateral outline and its posterior caudal process is more ventrally situated. stratigraphic and geographic distribution: the present species was previously recorded in the lower and upper cenomanian of egypt (boukhary et al., 1977; bassiouni, 2002). in the present area, it is observed in the upper cenomanian, samples s–02 and s–03. genus metacytheropteron oertli, 1957 type species: metacytheropteron elegans oertli, 1957 metacytheropteron berbericum (bassoullet & damotte, 1969) (pl. 1, figs. 16–20) 1969 cytheropteron berbericus n.sp. bassoullet & damotte, p. 137, pl. 2, fi g. 7a–d 1973 metacytheropteron parnesi sohn – grosdidier, p. 150, pl. 6, fi g. 54a–d 1974 metacytheropteron berbericum (bassoullet & damotte) – rosenfeld & raab, p. 12, pl. 2, fi gs. 26–28; pl. 5, fi gs. 2–4 1975 metacytheropteron berbericus (bassoullet & damotte) – colin & el dakkak, p. 58, pl. 2, fi gs. 8–11 1977 metacytheropteron berbericum (bassoullet & damotte) – boukhary et al., p. 158, pl. 1, fi gs. 2a–b, 3a–c 1978 metacytheropteron berbericus (bassoullet & damotte) – babinot et. al., p. 21, pl. 4, fi g. 10 1980 metacytheropteron berbericus (bassoullet & damotte) – ben youssef, p. 89, pl. 6, fi g. 21 1981a metacytheropteron berbericus (bassoullet & damotte) – bismuth et al., p. 225, pl. 8, fi gs. 7–8 1983 metacytheropteron pleura n.sp. al-furaih, p. 2, pl. 1, fi gs. 1–2 1983 metacytheropteron berbericus (bassoullet & damotte) – gargoui-razgallah, p. 150, pl. 27, fi gs. 2–5 plate 1 1–2 cytherella aegyptiensis colin & el dakkak, 1975. galala formation, sample 02, 1, ac–01, l 0.92 mm, lvc; 2, ac–02, w 0.53 mm, dvc. 3–4 paracypris dubertreti damotte & saint-marc, 1972. galala formation, sample 02, 3, ac–03, l 0.72 mm, lvc; 4, ac–04, l 0.74 mm, rvc. 5–8 dolocytheridea atlasica bassoulet & damotte, 1969. galala formation, sample 03, 5, ac–05, l 0.76 mm, rvc; 6, ac–06, l 0.72 mm, lvc; 7, ac–07, w 0.37 mm, dvc; 8, ac–08, l 0.68 mm, rvc. 9–12 eocytheropteron? cf. punctata (bassiouni, 2002). galala formation, sample 02, 9, ac–09, w 0.26 mm, dvc; 10, ac–10, l 0.43 mm, rvc; 11, ac–11, l 0.43 mm, lvc; 12, ac–12, l 0.45 mm, lvc. 13–15 neocythere? mackenziei (majoran, 1989). galala formation, sample 02, 13, 15, females: 13, ac–13, l 0.48 mm, rvc; 15, ac–15, l 0.46 mm, lvc; 14, male, ac–14, l 0.49 mm, rvc. 16–20 metacytheropteron berbericum (bassoullet & damotte, 1969). galala formation, sample 02, 16–19, females: 16, ac–16, l 0.48 mm, rvc; 17, ac–17, l 0.51 mm, lvc; 18, ac–18, w 0.27 mm, dvc; 19, ac–19, l 0.51 mm, lvc; 20, male, ac–20, l 0.61 mm, rvc. abbreviations: rvc: right view carapace, lvc: left view carapace, dvc: dorsal view carapace, l: length, w: width. geologia croaticaboukhary et al.: late cenomanian ostracod faunas from the area south of ain sukhna, western side of the gulf of suez, egypt 23 geologia croatica geologia croatica 62/1 24 1985 metacytheropteron berbericus (bassoullet & damotte) – viviére, p. 251, pl. 26, fi gs. 9–10 1988 metacytheropteron berbericus (bassoullet & damotte) – athersuch, p. 7201, pl. 1, fi gs. 12–13 1989 metacytheropteron berbericus (bassoullet & damotte) – majoran, p. 14, pl. 6, fi gs. 1–2 1991 metacytheropteron berbericus (bassoullet & damotte) – shahin & kora., p. 683, fi g. 9:20 1991 metacytheropteron cf. berbericus (bassoullet & damotte) – szczechura et al., p. 23, pl. 4, fi g.15; pl. 10, fi g. 1 1991 metacytheropteron berbericus (bassoullet & damotte) – shahin, p. 142, pl. 3, fi gs. 5–6 1991 metacytheropteron berbericus (bassoullet & damotte) – shahin & kora, p. 682, fi g. 9:20 1994 metacytheropteron berbericus (bassoullet & damotte) – athersuch, p. 263, pl. 12.1, fi gs. 12–13 1994 metacytheropteron berbericus (bassoullet & damotte) – shahin et al., p. 51, pl. 3, fi gs. 2–3 1995 metacytheropteron berbericus (bassoullet & damotte) – abdallah et al., p. 531, fi g. 20:12 1997 metacytheropteron berbericum (bassoullet & damotte) – ismail & soliman, p. 174, pl. 3, fi gs. 8–9 1999 metacytheropteron berbericum (bassoullet & damotte) – ismail, p. 309, pl. 3, fi g. 13 2001 metacytheropteron berbericum (bassoullet & damotte) – ismail, fi g. 12:11–12 2001 metacytheropteron berbericum (bassoullet & damotte) – morsi & bauer, p. 390, pl. 3, fi gs. 14–15 2002 metacytheropteron berbericum (bassoullet & damotte) – bassiouni, p. 46, pl. 10, fi gs. 4–5 material: 29 specimens. dimensions: length, 0.48–0.51 mm; height, 0.25–0.28 mm; width 0.27 mm (females); length, 0.61 mm; height, 0.26 mm (male). stratigraphic and geographic distribution: this species has a wide distribution in north africa and the middle east. in algeria, where it was fi rst described, it was recorded throughout the cenomanian (bassoullet & damotte, 1969; viviére, 1985; majoran, 1989). it was also found in the upper albian–cenomanian of tunisia (ben youssef, 1980; bismuth et al., 1981a; gargouri-razgallah 1983; abdallah et al., 1995), cenomanian of israel (rosenfeld & raab, 1974; majoran, 1989), jordan (babinot & basha, 1985; schulze et al., 2004), saudi arabia (al-furaih, 1983), oman (athersuch, 1988, 1994; babinot & boulardillon de grissac, 1989) and iran (grosdidier, 1973). from southern europe, it was recorded in the upper cenomanian of the western portugese basin (babinot, et al., 1978). in egypt, it is similarly known from the (?)albian–cenomanian (colin & el dakkak, 1975; boukhary et al., 1977; shahin, 1991; shahin & kora, 1991; szczechura, et al. 1991; shahin et al., 1994; ismail & soliman, 1997; ismail, 1999, 2001; morsi & bauer, 2001; bas siouni, 2002). in the present material, metacytheropteron berbericum comes from the upper cenomanian, samples s–01, s–02, s–03 and s–04. family progonocytheridae mertens, 1956 genus neocythere mertens, 1956 type species: neocythere vanveenae mertens, 1956 neocythere? mackenziei (majoran, 1989) (pl. 1, figs. 13–15) 1989 ‘eucythere’ mackenziei n.sp. majoran, p. 13, pl. 5, fi gs. 1–5 2002 ?eucythere mackenziei majoran – bassiouni, p. 31, pl. 15, fi gs. 3–4 material: 4 specimens. dimensions: length: 0.46–0.48 mm; height: 0.29–0.33 mm (females); length: 0.49 mm; height: 0.26 mm (males). remarks: majoran (1989) who erected and describ ed this species, and bassiouni (2002), both assigned it the present species tentatively to the genus eucythere. they both realized from the external features that this species does not really belong to eucythere as it possesses eye tubercles and a different surface sculpture; they mentioned that it possibly represents a new genus. the use of eucythere was only based on outline similarity as they did not fi nd well-preserved open valves to investigate the internal features. the material found by majoran was mostly represented by sediment-fi lled open valves with poorly preserved hinges, apparently merodont/entomodont, and bassiouni merely recorded a single carapace. no open valves were discovered in the present study. we agree that this species most probably belongs to a new genus that is more likely, as mentioned by bassiouni (2002), related to the progonocytheridae. therefore, we prefer to assign the present species tentatively to the progonocytherid genus neocythere, which was also mentioned by majoran as being comparable with the present species, than to eucythere, although it also different. neocythere deviates from the present species in having a more regularly ornamented surface and an ovoid rather than triangular lateral outline. however, the tentative assignment to neocythere has been made as we could not fi nd a better match and an exact generic assignment must wait until well-preserved open valves enabling access to the internal features are discovered. stratigraphic and geographic distribution: the present species was fi rst recorded from the upper cenomanian of algeria (majoran, 1989). in egypt, it was recorded from the lower cenomanian of north sinai (bassiouni, 2002). this species is recorded here in the upper cenomanian, samples s–01 and s–02. family trachyleberididae sylvester-bradley, 1948 subfamily trachyleberidinae sylvester-bradley, 1948 genus cythereis jones, 1849 type species: cytherina ornatissima reuss, 1846 cythereis namousensis bassoullet & damotte, 1969 (pl. 2, figs. 1–5) 1969 cythereis namousensis n.sp. bassoullet & damotte, p. 134, pl. 1, fi g. 3a–d 1974 cythereis namousensis bassoullet & damotte – rosenfeld & raab, p. 17, pl. 3, fi gs. 17–18 1977 cythereis namousensis bassoullet & damotte – boukhary et al., p. 158, pl. 1, fi g. 5a–d geologia croaticaboukhary et al.: late cenomanian ostracod faunas from the area south of ain sukhna, western side of the gulf of suez, egypt 25 1980 cythereis namousensis bassoullet & damotte – ben youssef, p. 78, pl. 6, fi gs. 5–8 1981a cythereis namousensis bassoullet & damotte – bismuth et al., p. 232, pl. 8, fi gs. 9–10 1983 cythereis namousensis bassoullet & damotte – gargouri-razgallah, p. 154, pl. 29, fi g. 1 1989 cythereis namousensis bassoullet & damotte – majoran, p. 21, pl. 10, fi gs. 13–16 1991 cythereis namousensis bassoullet & damotte – shahin, p. 145, pl. 3, fi g. 12 1994 cythereis namousensis bassoullet & damotte – shahin et al., p. 56, pl. 3, fi gs. 21–22 1995 cythereis namousensis bassoullet & damotte – abdallah et al., p. 531, fi g. 20:10 2001 cythereis namousensis bassoullet & damotte – ismail, fi g. 13:9–10 2001 cythereis namousensis bassoullet & damotte – morsi & bauer, p. 392, pl. 4, fi gs. 10–11 2002 cythereis namousensis bassoullet & damotte – bassiouni, p. 70, pl. 15, fi gs. 13–16 material: 15 specimens. dimensions: length: 0.65–0.67 mm; height: 0.37–0.38 mm; width: 0.34 mm (females); length: 0.69 mm; height: 0.36 mm; width: 0.31 mm (male). stratigraphic and geographic distribution: the present species is common in the cenomanian rocks in algeria (bassoullet & damotte, 1969; majoran, 1989), israel (rosenfeld & raab, 1974; majoran, 1989), tunisia (ben youssef, 1980; bismuth et al., 1981a; gargouri-razgallah, 1983; abdallah et al., 1995), jordan (schulze et al., 2004), and egypt (boukhary et al., 1977; shahin et al., 1994; shahin, 1991; ismail, 2001; morsi & bauer, 2001; bassiouni 2002). here, it comes from the upper cenomanian, samples s–01, s–02, s–03 and s–04. genus peloriops al-abdul-razzaq, 1979 type species: cythereis ziregensis bassoullet & damotte, 1969 peloriops aegyptiaca morsi & bauer, 2001 (pl. 2, fig. 7) 2001 peloriops aegyptiaca n.sp. morsi & bauer, p. 394, pl. 5, fi gs. 4–5, 8 material: a single specimen. dimensions: length: 0.46 mm; height: 0.25 mm. stratigraphic and geographic distribution: this species was fi rst described from the upper cenomanian of egypt (morsi & bauer, 2001). in the present section, it is also present in the upper cenomanian, sample s–03. peloriops pustulata (rosenfeld, 1974) (pl. 2, figs. 8–10) 1974 planileberis pustulata n.sp. rosenfeld in rosenfeld & raab, p. 19, pl. 3, fi gs. 2–5; pl. 6, fi gs. 1–4 1977 planileberis pustulata rosenfeld – boukhary et al., p. 159, pl. 1, fi gs. 1a–d 1979 peloriops ulosa n.sp. al-abdul-razzaq, p. 51, pl. 1, fi gs. 4–5, 11, 15; pl. 2, fi g.3 1981a cythereis ziregensis bassoullet & damotte–bismuth et al., p. 234, pl. 8, fi gs. 9–12 1988 peloriops ulosa al-abdul-razzaq–athersuch, p. 1203, pl. 4, fi g. 10–11 pars 1989 peloriops ziregensis? (bassoullet & damotte) – majoran, p. 24, pl. 15, fi gs. 4–13; non pl. 15, fi gs. 1–3 1991 peloriops sp. szczechura et al., p. 25, pl. 8, fi g. 8 1994 peloriops ulosa al-abdul-razzaq – athersuch 1994, p. 263, pl. 12.2, fi gs. 2, 4 1994 planileberis pustulata rosenfeld – shahin et al., p. 57, pl. 3, fi gs. 29–31 2001 peloriops pustulata (rosenfeld) – morsi & bauer, p. 394, pl. 5, fi gs. 6–7, 9 2002 peloriops pustulata (rosenfeld) – bassiouni, p. 88, pl. 21, fi gs. 9–13 material: 10 specimens. dimensions: length: 0.66–0.71 mm; height: 0.37–0.38 mm; width: 0.24–0.26 mm. stratigraphic and geographic distribution: this species was first described from the cenomanian of israel (rosenfeld & raab, 1974). it is also known from the cenomanian of algeria (majoran, 1989), tunisia (bismuth et al., 1981a), kuwait (al-abdul-razzaq, 1979), oman (athersuch, 1988, 1994) and egypt (boukhary et al., 1977; shahin et al., 1991; szczechura et al., 1991; morsi & bauer, 2001; bassiouni, 2002). in the present material, it is recorded in the upper cenomanian, samples s–01, s–02 and s–03. genus veeniacythereis gründel, 1973 type species: cythereis imparia gründel, 1968 veeniacythereis streblolophata schista al-abdul-razzaq & grosdidier, 1981 (pl. 2, figs. 11–15) 1973 cythereis ir c 4, grosdidier, pl. 8, fi gs. 66a–d pars 1975 veeniacythereis jezzineensis (bischoff) – colin & eldak kak, p. 56, pl. 2, fi g. 1; non pl. 1, fi gs. 11–12; non pl. 2, fi g. 2 1981 veeniacythereis streblolophata schista n.sp. al-abdul-razzaq & grosdidier, 185, pl. 2, fi gs. 1–5 pars 1981a veeniacythereis streblolophata al-abdul-razzaq – bismuth et al., p. 233, pl. 10, fi gs. 5–7, non fi gs. 3–4 1983 veeniacythereis streblolophata schista al-abdul-razzaq & grosdidier–gargouri-razgallah, p. 55, pl. 29, fi gs. 2–6 pars 1985 veeniacythereis gr. jezzineensis (bischof) – viviére, p. 185, pl. 11, fi g. 5; non pl. 11, fi gs. 6–11 1988 veeniacythereis streblolophata schista al-abdul-razzaq & grosdidier – athersuch, pl. 3, fi gs. 1–2 1991 veeniacythereis ex. gr. streblolophata al-abdul-razzaq & grosdidier – szczechura et al., p. 29, pl. 7, fi gs. 1–3, 5–8 1991 veeniacythereis jezzinensis (bischoff) – shahin, p. 144, pl. 3, fi gs. 8–9 1994 veeniacythereis streblolophata schista al-abdul-razzaq & grosdidier – athersuch, pl. 12.3, fi gs. 4–5 1994 veeniacythereis streblolophata schista al-abdul-razzaq & grosdidier – shahin et al., p. 60, pl. 4, fi gs. 14–15 1997 veeniacythereis jezzinensis (bischoff) – ismail & soliman, p. 182, pl. 3, fi gs. 14–15 1997 cythereis cf. canteriolata (crane) – ismail & soliman, p. 178, pl. 3, fi gs. 19–20 geologia croatica geologia croatica 62/1 26 1997 cythereis gapensis (alexander) – ismail & soliman, p. 180, pl. 3, fi gs. 21–22 2001 veeniacythereis streblolophata schista al-abdul-razzaq & grosdidier – morsi & bauer, p. 396, pl. 5, fi gs. 13–15 2002 veeniacythereis streblolophata schista al-abdul-razzaq & grosdidier – bassiouni, p. 81, pl. 18, fi gs. 13–16; pl. 19, fi g. 12 material: 19 specimens. dimensions: length: 0.70 mm; height: 0.42 mm; width, 0.37 mm (females); length: 0.73–0.75 mm; height: 0.35–0.42 mm (males). stratigraphic and geographic distribution: the present subspecies was previously found in the arabian gulf region from the albian–lower cenomanian of iran (grosdidier, 1973), cenomanian of oman (athersuch, 1988, 1994) and upper cenomanian of kuwait (al-abdulrazzaq & grosdidier, 1981). it was also reported from the cenomanian of jordan (schulze et al., 2004). in north africa, it was recorded in the cenomanian of tunisia (bismuth et al., 1981a; garghouri-razgallah, 1983), lower cenomanian of algeria, (viviére, 1985) and (?) albian–cenomanian of egypt (colin & el dakkak, 1975; shahin, 1991; szczechura et al., 1991; shahin et al., 1994; ismail & soliman, 1997; morsi & bauer, 2001; bassiouni, 2002). in the present section, it is retrieved from in the upper cenomanian, samples s–01 and s–02. gen. indet. sp. (pl. 2, fig. 6) material: a single specimen. dimensions: length: 0.42 mm; height: 0.21 mm. remark: this species is represented only by a single carapace recalling the trachleberidids, hence it is assigned to the family trachyleberididae. it resembles praephacorhabdotus? jirensis from the cenomanian of morocco (andreu-boussut, 1991). however, the present specimen is relatively smaller in size and has a shorter and thicker ventral rib occupying the mid-ventral part of the lateral surface; in praephacorhabdotus? jirensis this rib is longer, thinner and extends farther anteriorly to join the anterior marginal rib at the anteroventral corner. stratigraphic and geographic distribution: upper cenomanian, sample s–03. 3. biostratigraphic implications cenomanian ostracod biostratigraphy in north african and the middle east areas was discussed by rosenfeld & raab (1974), bismuth et al. (1981a), athersuch (1988, 1994), hataba & ammar (1990), szczechura et al. (1991), shahin (1991), shahin & kora (1991), shahin et al. (1994), damotte (1995), ismail (2001), morsi & bauer (2001) and bassiouni (2002). depending on previous documentations, the species constituting the assemblage found in the present section are dominated by typical cenomanian taxa consisting of cytherella aegyptiensis, neocythere? mackenzei, eocytheropteron? cf. punctata, cythereis namousensis, peloriops aegyptiaca, peloriops pustulata and veeniacythereis streblolophata schista. fewer taxa having longer ranges are represented by dolocytheridea atlasica and metacytheropteron berbericum, which are widespread in the cenomanian, but also have records in the albian in tunisia (ben youssef, 1980; bismuth et al., 1981a) iran (grosdidier, 1973) and questionably egypt (szczechura et al., 1991), as well as paracypris dubertreti, which is also known from the aptian/albian of israel (rosenfeld & raab, 1984) and egypt (hewaidy & morsi, 2001; bassiouni, 2002) and the early turonian of algeria (vivére, 1985). in terms of biostratigraphic zonation, many local ostracod zonal schemes were proposed for different areas by rosenfeld & raab (1974) in israel, bismuth et al. (1981a) in tunisia, athersuch (1988, 1994) in the arabian gulf area, and hattaba & ammar (1990), shahin et al. (1994), and ismail (2001) in egypt. in the present section, many of the recorded species were partly utilized in the zonal schemes proposed by rosenfeld & raab (1974) and ismail (2001), where dolocytheridea atlasica, metacytheropteron berbericum, cythereis namousensis and peloriops pustulata were used among the species characteristic for the metacytheropteron berbericum acme zone of rosenfeld & raab and the cythereis algeriana–metacytheropteron berbericum zone of ismail, both assigned to the late cenomanian. moreover, peloriops aegyptiaca, which is also found among the recorded fauna, plate 2 1–5 cythereis namousensis bassoullet & damotte, 1969. galala formation, sample 03, 1, 4–5 females:1, ac–21, l 0.65 mm, rvc; 4, ac–24, w 0.34 mm, dvc; 5, ac–25, l 0.67 mm, lvc; 2–3, males: 2, ac–22, w 0.69 mm, rvc; 3, ac–23, w 0.31 mm, dvc. 6 gen. indet. sp. galala formation, sample 02, ac–26, l 0.42 mm, rvc. 7 peloriops aegyptiaca morsi & bauer, 2001. galala formation, sample 03, ac–27, l 0.46 mm, rvc. 8–10 peloriops pustulata (rosenfeld & raab, 1974). galala formation, sample 03, 8, ac–28, w 0.24 mm, dvc; 9, ac–29, l 0.71 mm, lvc; 10, ac–30, l 0.66 mm, rvc. 11–15 veeniacythereis streblolophata schista al-abdulrazzaq & grosdidier, 1981. galala formation, sample 02, 11, 13 females: 11, ac–31, l 0.70 mm, rvc; 13, ac–33, w 0.37 mm, dvc; 12, 14–15, males: 12, ac–32, l 0.75 mm, rvc; 14, ac–34, l 0.73 mm, rvc; 15, ac–35, l 0.75 mm, rvc. abbreviations: rvc: right view carapace, lvc: left view carapace, dvc: dorsal view carapace, l: length, w: width. geologia croaticaboukhary et al.: late cenomanian ostracod faunas from the area south of ain sukhna, western side of the gulf of suez, egypt 27 geologia croatica geologia croatica 62/1 28 was described from the upper cenomanian of sinai in egypt (morsi & bauer, 2001), together with a similar assemblage. therefore, the recorded association could be utilized to indicate a late cenomanian age for the studied section. 4. palaeobiogeographic implications the most comprehensive synthesis of ostracod palaeobiogeographic aspects in the tethyan region was previously made by babinot (1985), babinot & colin (1988), andreu (1993), gebhardt (1999), and luger (2003). supporting contributions were also given by babinot et al. (1978), damotte (1985, 1995), viviére (1985), athersuch (1988), babinot & boulardion de grissac (1989); majoran (1989), colin et al. (2001) and morsi & bauer (2001). during the cenomanian, the separation between the northern and southern margins of tethys became total and two well-differentiated bioprovinces were individualized: a northern bioprovince comprising west europe, and a southern bioprovince in north africa and the middle east (babinot, 1985; babinot & colin, 1988), in the midst of which egypt was situated. the south tethyan bioprovince was named ‘bioprovince of veeniacythereis jezzineensis and metacytheropteron berbericum’ or the afro–arabian north-gondwanian bioprovince, and has been extended to incorporate the northern part of east africa (babinot & colin, 1988; colin et al., 1991). at the generic level, this bioprovince was characteristically inhabited by representatives of dolocytheridea, glenocythere, matacytheropteron, nigeroloxoconcha, peloriops and veeniacythereis, together with cosmopolitan genera such as cytherella, bairdia, bythocypris, bythoceratina and cythereis. at the species level, palaeogeographic control on ostracod faunal distribution is also emphasized by a large number of species documented in a large number of publications (e.g. al-abdul-razzaq & grosdidier, 1981; damotte, 1985; babinot & boulardion de grissac, 1989; majoran, 1989; andreu-boussut, 1991; andreu, 1993; gebhardt, 1999; colin et al., 2001; morsi & bauer, 2001; bassiouni, 2002; luger, 2003). in the present fi gu re 3: palaeobiogeography of selected south tethyan marine ostracod species (map modifi ed after barron et al., 1981; oceanic circulation after haq, 1984). (1) paracypris dubertreti (2) dolocytheridea atlasica (3) metacy theropteron berbericum (4) cythereis namou sensis (5) peloriops pustulata (6) veeniacythereis streblolophata schista. table 2: geographic distribution of the recorded ostracod fauna in diff erent countries. cy th er el la a eg yp tie ns is pa ra cy pr is d ub er tr et i d ol oc yt he rid ea a lta si ca eo cy th er op te ro n? cf . p un ct at a n eo cy th er e? m ac ke nz ie m et ac yt he ro pt er on b er be ric um cy th er ei s n am ou se ns is pe lo rio ps a eg yp tia ca pe lo rio ps p us tu la ta ve en ia cy th er ei s s tr eb lo lo ph at a sc hi st a west africa • morocco • • • • algeria • • • • • • tunisia • • • • • libya • egypt • • • • • • • • • • israel • • • • • • jordan • • • • • • • libanon • • kuwait • • • oman • • • • iraq • iran • • • somalia • south europe • geologia croaticaboukhary et al.: late cenomanian ostracod faunas from the area south of ain sukhna, western side of the gulf of suez, egypt 29 athersuch, j. (1988): the biostratigraphy of cretaceous ostracods from oman.– in: hanai, t., ikeya, n. & ishizaki, k (eds.): evolutionary biology of ostracoda; its fundamentals and applications. proceedings of the 9th international symposium on ostracoda, (shizuoka, 1985). kodansha ltd., tokyo and elsevier, amesterdam, developments in paleontology and stratigraphy, 11, 1187–1206. athersuch, j. (1994): the biostratigraphic signifi cqance of cretaceous ostracods from the arabian gulf.– in: simmons, m.d. (ed.): micropaleontology and hydrocarbon exploration in the middle east. chapmann & hall, london, 253–265. babinot, j.-f. (1985): paléobiogéographie des ostracods du crétacé supérieur des marges ouest-européennes et nord-africaines de la tethys.– bull. soc. géol. fr., paris, (8)1,5, 739–754. babinot, j.-f. & basha, s.a. (1985): ostracods from the early cenomanian of jordan. a preliminary report.– geobios, lyon, 18/2, 257–262. babinot, j.-f., berthou, p.y., colin, j.-p. & lauverjat, j. (1978): les ostracods du cénomanien du bassin occidental portugais: biostratigraphie, et affi nités paléobiogéographiques.– cahiers micropaléontol., 3, 11–23. babinot, j.-f. & colin, j.-p. (1988): paleobiogeography of tethyan cretaceous marine ostracods.– in: hanai, t., ikeya, n. & ishizaki, k. (eds.): evolutionary biology of ostracoda; its fundamentals and applications, proceedings of the 9th international symposium on ostracoda, shizuoka, 1985, kodansha ltd., tokyo and elsevier, amsterdam. developments in paleontology and stratigraphy, 11, 823–939. babinot, j.f., bourdillon de grissac, c. (1989): associations d’ostracods de l’albien-maastrichtien du dhofar (oman). affi nités paléobiogeéographiques et implications géodynamiques.– bull. soc. géol. fr., 287–294. barron, e.j., harrison, c.g.a., solan, j.l. & hay, w.w. (1981): paleogeography, 180 million years ago to present.– eclog. geol. helv., 74/2, 443–470. bassiouni, m.a.a. (2002): mid-cretaceous (aptian–early turonian) ostracoda from sinai, egypt.– neue paläontol. abhand., dresden, 5, 1–123. bassoullet, j.-p. & damotte, r. (1969): quelques ostracods nouveaux du cénomano-turonien de l`atlas saharien occidental (algérie).– rev. micropaléontol., 12/3, 130–144. bate, m. (1972): upper cretaceous ostracoda from the carnarvon basin, western australia.– the palaeontological association, london, spec. pap. in palaeontol., 10, 1–85. ben youssef, m. (1980): etude stratigraphique et micropaléontologique du crétace des djebels koumine et kharroub.– thése docteur de 3e cycle, université nice, 104 p. bismuth, h., boltenhagen, c., donze, p., lefevre, j. & saint-marc, p. (1981a): le crétacé moyen et supérieur du djebel semmama (tunisie du centre-nord); microstratigraphie et évolution sédimentologique.– société nationale d’elf aquitaine, 5, 213–245. bismuth, h., donze, p., lefevre, j. & saint-marc, p. (1981b): nouvelle espéces d’ostracodes dans le crétacé moyen et supérieur du djebel semmama (tunisie du centre-nord).– cahiers micropaléontol., 3, 51–69. bold, w.h. van den. (1964): ostracoden aus der oberkreide von abu rawash, ägypten.– palaeontograph. a, 123/4–6, 111–136. boukhary, m., eissa, r. & kerdany, m. (1977): some ostracod species from the galala formation, western coast of the gulf of suez, egypt. proceedings of the egyptian academy of science, cairo, 30, 155–161. colin, j.-p. & el dakkak, m.w. (1975): quelques ostracods du cénomanien du djebel nezzazat, sinai, egypte.– rev. espań. micropaleontol., special issue, 49–60. study, the recorded ostracod fauna is composed of taxa of a typical marine shelf setting. most of the taxa are typical south tethyan forms and are already known from different regions in this province, from morocco in the west to the arabian gulf region in the east. of the species discovered, cytherella aegyptiensis, paracypris dubertreti, dolocytheridea atlasica, metacytheropteron berbericum, cythereis namousensis, peloriops pustulata, and veeniacythereis streblolophata schista show a wide distribution with records in morocco, algeria, tunisia, egypt, jordan, israel, lebanon, kuwait, oman and iran (see tab. 2 and fig. 3). dolocytheridea atlasica was additionally cited to have records in libya, somalia (colin et al., 2001), and iraq (riche & pristat, 1980). the palaeogeographic distribution of neocythere? mackenziei is still not very well-known as it has so far only been recorded only in algeria (majoran, 1989) and egypt (bassiouni, 2002; present study). the relationship with the northern tethys is weakly pronounced and only metacytheropteron berbericum has a record in southern europe from the western portugese basin (babinot et al., 1978). babinot & colin (1988) suggested that the depth of tethys and also the unfavourable currents could be the reasons for the eliminated ostracod faunal exchanges between northern and southern tethys. acknowledgement the authors are grateful to prof. michael schudack (free university of berlin, germany) and dr. jean-paul colin (cestas, france) for their critical review and suggestions that enhanced the quality of the manuscript. special thanks are due to prof. hans-joachim kuss (university of bremen, germany) for his help in usage of the sem for photographing the ostracod material in his department. for technical assistance, thanks are also due to dr. hartmut mai (university of bremen). references abdallah, a.m. & adindani, a. (1963): stratigraphy of upper paleozoic rocks, western side of the gulf of suez.– geological survey of egypt, cairo, 25, 18. abdallah, h., memmi, l., damotte, r., rat, p. & magniezjannin, f. (1995): le crétacé de la chaîne nord des chotts (tunisie du centre-sud): biostratigraphie et comparaison avec les région voisines.– cretaceous res., 16, 487–538. al-abdul-razzaq, s. (1979): peloriops, a new ostracode genus from the cretaceous of kuwait.– 7th international symposium of ostracoda, (beograd 1979). serbian geological society, 47–54. al-abdul-razzaq, s. (1980): new eocytheropteron species with reversed valve structure.– micropaleontology, 26/4, 444–448. al-abdul-razzaq, s. & grosdidier, e. (1981): ostracode index species from the cenomanian of the south shelf of the tethys sea.– bulletin des centres de recherche exploration.– production elf-aquitaine, 5/2, 173–191. al-furaih, a.a.f. (1983): middle cretaceous (cenomanian) ostracoda from the wasia formation of saudi arabia.– paleontological contributions of the university of kansas, 108, 1–6. andreu-boussut, b. (1991): les ostracods du crétacé moyen (barrémien à turonien), le long d’une transversale agadir – nador (maroc).– strata, series 2, 14, 765 p. andreu, b. (1993): associations d’ostracods des marges téthysiennes et atlantique marocaines de l’albian au turonien.– geobios, 26/1, 69–84. geologia croatica geologia croatica 62/1 30 colin j.-p., platel, j.-p., roger, j. & tambareau, y. (2001): nouvelles données sur les faunes d’ostracods de l’albien et du cénomanien d’oman: taxonomie et paléobiogéographie.– in: weiss, r.h. (ed.): contributions to geology and palaeontology of gondwana. geological institute, university of cologne, 89–109. damotte, r. (1985): les ostracods du crétacé moyen sud-mésogéen et leur répartition paléogéographique.– bull. soc. géol. fr., paris, 8, 733–737. damotte, r. (1995): the biostratigraphy and paleobiogeography of the upper cretaceous-basal tertiary ostracods from north africa, mali and congo.– cretaceous res., 16, 35–366. damotte, r. & saint-marc, p. (1972): contribution à la connaissance des ostracods crétacé du liban.– rev. espań. micropaleontol., 4/3, 273–296. gargouri-razgallah, s. (1983): le cénomanien de tunisie centrale, étude paléoécologique, stratigraphique, micropaléontologique et paléogéographique.– thése docteur dés-sciences, univérsité claude bernard, lyon, 215 p. gebhardt, h. (1999): cenomanian to coniacian biogeography and migration of north and west african ostracods.– cretaceous res., 20, 215–229. gerry, e. & rosenfeld, r. (1973): amphicytherura distincta and neocyprideis vandenboldi (ostracoda), new species from the cenomanian–turonian of israel.– rev. espań. micropaleontol., 5/1, 99– 105. grosdidier, e. (1973): associations d’ostracods du crétacé d’iran.– revue de l’institut francais de pétrole, 28, 131–168. haq, b.u. (1984): paleoceanography: a synoptic overview of 200 million years of ocean history.– in: haq, b.u. & milliman, j.d. (eds.): marine geology and oceanography of arabian sea and coastal pakistan. van nostrand reinhold co., new york, 201–231. hataba, h. & ammar, g. (1990): comparative stratigraphic study on the upper cenomanian–lower senonian sediments between the gulf of suez and western desert, egypt.– egpc 10th exploration and prododuction conference, cairo, 1–16. hewaidy, a.a. & morsi, a.m. (2001): lower cretaceous (aptianalbian) foraminifera and ostracoda from northern sinai, egypt.– egypt. j. paleontol., 1, 229–252. horn, d.j., cohen, a. & martens, k. (2002): taxonomy, morphology and biology of quaternary and living ostracoda.– in: holmes, j.a. & chivas, a.r. (eds.): the ostracoda, applications in quaternary research. american geophysical union, 131, 5–36. ismail, a.a. (1999): aptian-turonian ostracods from northern sinai, egypt.– egypt. j. geol., cairo, 43/2, 293–315. ismail, a.a. (2001): correlation of cenomanian-turonian ostracods of gebel shabraweet with their counterpart in egypt, north africa and the middle east.– neues jahrb. geol. paläontol., monat shefte., 9, 513–533. ismail, a.a. & soliman, s.i. (1997): cenomanian-santonian foraminifera and ostracods from horus well-1, north western desert, egypt.– micropaleontol., 43/2, 165–183. kerdany, m.t., eissa, r.a. & labib, f. (1973): quelques foraminifères cénomaniens de la partie oust de la region du golfe de suez (égypte).– rev. micropaléontol., 16/2, 89–96. luger, p. (2003): paleobiogeography of late early cretaceous to early paleocene marine ostracoda in arabia and north to equatorial africa.– palaeogeogr., palaeoclimatol., palaeoecol., 196/3, 319– 342. majoran, s. (1988): comments on a miscellaneous ostracod group from the mid-cretaceous of the south shelf of the tethys sea.– j. afr. earth sci., 6, 691–702. majoran, s. (1989): mid-cretaceous ostracoda of northeastern algeria.– fossils & strata, 27, 1–67. majoran, s. (1996): mid-cretaceous “veeniacythereis” (ostracoda) from africa and the middle east.– neues jahrb. geol. paläontol., monatshefte, 1996/3, 183–192. morsi, a.m. & bauer, j. (2001): cenomanian ostracods from sinai peninsula, egypt.– rev. paléobiol., 20/2, 377–414. orabi, h.o. & ismail, a.a. (1993): cenomanian–turonian ostracods from west-central sinai, egypt.– science journal of the faculty of science, monoufi a university, shebin el koum, 7, 131–157. riche, p. & pristat, b. (1980): paléogéographie du crétacé moyen du proche et moyen-orient et sa signifi cation pétrolière.– proceedings of the 10th world petroleum congress. heydem & sons, london, 2, 57–75. rosenfeld, a. & raab, m. (1974): cenomanian–turonian ostracods from the judea group in israel.– bull. geol. surv. isr., jerusalem, 62, 1–64. rosenfeld, a. & raab, m. (1984): lower cretaceous ostracods from israel and sinai.– isr. j. earth sci., 33, 85–134. schulze, f., marzouk, a.m., bassiouni, a.a. & kuss, j. (2004): the late albian–turonian carbonate platform succession of west-central jordan: stratigraphy and crisis.– cretaceous res., 25, 709–737. shahin, a. (1991): cenomanian-turonian ostracods from gebel nezzazat, southwestern sinai, egypt, with observations on δ13 c values and the cenomanian/turonian boundary.– j. micropalaeontol., 10/2, 133–155. shahin, a. & kora, m. (1991): biostratigraphy of some upper cretaceous successions in the eastern central sinai, egypt.– neues jahrb. geol. paläontol., monatshefte., 1991/11, 671–692. shahin, a., kora, m. & semiet, a. (1994): cenomanian ostracods from west central sinai, egypt.– mansoura university science bulletin (natural sciences), mansoura, 21/1, 33–102. szczechura, j., abd-elshafy, e. & babinot, j.-f. (1991): late albian to early/mid-cenomanian ostracods from northern galala plateau, egypt.– acta palaeontol. polon., 36/1, 3–38. viviére, j.-l. (1985): les ostracods du crétacé supérieur (varconian à campanian basal) de la région de tebessa (algérie du nord-est. stratigraphie, paléoécologie, systématique).– mémoire de science de terre, universit é curie, paris, 85, 261 p. manuscript received january 2, 2008 revised manuscript accepted may 5, 2008 geol. croat. 49/2 1355 . 357 1 1 zag reb 1996 in memoriam i prof. donata nedela devide i (1911 1996) donata ncdcla devid6 was born on august 191h, 1911 in luclbrcg, croatia, and died 011 april 4th, 1996. she graduated from the faculty of phi losophy in zagreb, and from j935 unt il 1980, when she retired, was active in the department of geology, faculty of science, zagreb. from 1942-1948, she was with the geological-palaeontological musellill, where she was teaching ilumerous courses, e.g., lntroduction to stratigraphy, coal and petroleum geology, geology of yugoslavia, elc., but she also look practical courses in mineralogy and petrology at the faculty of science. however, her most important and most influential activity was in teaching geological mapping, through which coursc she was directly involved in the education of no less than 45 generations of croatian geologists. she was a personal mentor to more than 120 bse stu­ dents. i-ter publications, though never prolific have had a profound and last ing impact. iter most important paper concerned the g]obotruncanid foraminifera and produced different geological interpretations of many parts of the then yugoslavia, together with broader more regional implications . for everything she did for us, often at the expense of her private life, all of us who have had the privilege of being her pupils, shall remem~ ber her forever with grace and gratitude. lako smo znali da vee duze vrijeme nije bila dobrog zdravlja, vijesl 0 smrti !lase dugogodisnje nastavnice, koja jc prcminuia 4. travnja 1996., potresla je i duboko ozalostila gotovo sve zagrebackc, pa i hrvatske geologc (osim mozda onih najmladih koji ju nisu osobno poz­ navali, ali i oni su sigllrno curi za gospodu ncdclu, koja jc jos dok jc bila akt ivna, postala na nasem fakultctu legendom za geologijll i geolosko kartiranje). nadali smo se naime da ee "gospoda", kako smo ju cesto lovali, sada kada je odnedavno bila smjestena 1i instiluciju s odgovarajucolll njegom a dugo je odgadala odlazak iz svojeg stana na medveseaku pozivjeti jos kojll godinu u zasluzenom mini , ii boljim uvjetima, okruzena brigom koju treba ukazivati starijim osobama. nazalost, sudbi­ na je odredila drugacije. gospoda donata nedela devidc rodena j e 19. kalovoza 1911. u ludbrcgu. diplomirala jc tzv. fizicko­ geografsku grupu prcdmcla na filozofskom fakliitetu u zagrebu. od 1935. radi ii geolosko-paleontoloskom zavodu prirodos]ovno-matematickog fakliiteta, s kracim prckidom od 1942. do 1948. kada je bila kustosica min­ eralosko-petrografskog muzeja, no i kroz to vrijeme vrsila je asisten tskc duznosti iz kolcgija geoloske, pclro­ grafske i mincraloskc struke. god. 1949. postaje hono­ rami nastavnik, a 1961. visi predavac na geoloskom ocljelu prirodoslovno-matcmatickog fakultcta gdje radi kontinllirano do umirovljenja 1980. godine. predavala je razne geoloske kolcgije od kojih su najvazniji geo­ losko kaniranjc, gcologija jligoslavije, uvod u strati­ grafiju, geologija kaustobiolita. neke od tih predmeta slusali su ne samo studenti geologije na pmf-u, vee i 356 studenti rudarsko-geolosko-nartnog faklli teta, kao i sludent i gcografijc pmf-a. no najduzc i s najvccim zarom i osobnim angazmanom predavala je geolosko kartiranjc pri cemu jc sam a obavlj ala i svc pripadajuce praktikullle i icrcnskc vjczbe. upravo po lome poslala jc pojam cnluzijasta i prcdanog pcdagoga za sve slu ­ elclllc geologije . zbog svojeg aklivnog sudjelovanja u karliranju mnogih krajcva hrvalskc i zbog svekolikog poznavanja ie problemalike bila je predsjednik tadasnje rcpublickc i doprcdsjcdnik savcznc komisijc za izradu standarda za izv . ogk .lllgosiavijc, c lan nacionalnc kolllisijc za izradu geoloske karte europe, i elr. za 10 vrijemc od 1935. do 1980. odgojila jc 4s gcneracija geologa (nch svcucilisni nastavnici za toliko vrijcme svojeg eljelovanja ne oelgoje nili loliko pojeeli ­ naca). zaslo kazemo odgojila a ne obrazovala? zalo jer .ie geo losko karliranjc kolcgij koji le svagdasnji kruh gcologa, onaj zanal koji se mora svladali cia bi se uopce naucilo gcoloski razmisljati i zakljucivali, bez obzira cime se kasnijc bavili. ako k lome dodamo da jc osob­ no bila menlor cliplomskih raclova vise od 120-orici stu­ clcnata i stuclentica, od kojih su mllogi poslali sudionici, a ncmali braj i nos itclji izradc ogk hrvatskc, kao i cia sc vcl iki clio njez inih el iplol11anada zaposl io ii "nal"ta­ plinu", za kojega se zna sio znaci u gospodarstvu hrvatskc, onda jc prava rijcc da jc iljcz ino djelovanje na gclleracije hrvalskih geologa bilo zaista ncl11jcrijivo i ilcnadoklladivo. u 10111 svojcm poslll oclgajanjll geoloskih kaclrova ­ gos pocla ncdcla bilaje perrckcionisl. mllogi od ilas tada nisll shvacali pravo znacenj e njezille upomosli, a to je bila njezina golema i opravdana zelja cia iz svakog oel nas, pa i iz prosjccnih , i7.vucc one najboljc sio se moze izvllci, pa i pod cijcnll toga da sallla ii to lliozi puno vise truda, cncrg ije i vrcmena. mnogi su tek kasnije postali toga svjesni, koliko im j e la nj ezina zal jublj e nost ii gcologin. croaticn. 49/2 s lruku i upornosl cia jll prenese drllgillla koristila ii daljnjern gcoloskom sazrijevanju. no islo takva bila je i prema seb i. bila je pravi zaljllbljcnik ii slrukll puno puta smo od nje culi da ima same clvije vel ike ljubavi, svojll jasenku i svojll geologiju. kocl gospodc nedclc la za jjublj enost u geologiju nij e bila mladalac ka stras t, nego jc trajala cijcli zivot. zato jc i prema seb i bila pretjerano slroga. cesto nij e htjcla reei za ncko svojc islrazivanje cia je zavrseno (jako je naravno isti na da istrazivanje prirode nikad ne preslaje, ali ipak treba s vrclllena na vrijcll1c podvuci cnu i objav iti rezultate). zalo, zbog ic prevelikc samokrilicnosli i zbog prc(hl­ nosti naslavnoill procesll i svcsrdnog pomaganja kol c­ gam a i suradnieima, nije objavila veliki broj raclova. ali one s to jc objavila vccinom sallla, kao jedini autor imalo jc znacajnog odjeka s vrlo dalckoseznim uljeca­ jim<1 na geoloske interpretacije. racl koji.ie jos 1957. objavila 0 stra tigrarskolll znaccnju globotrlll1kanida bio je pionirski rad ie vrslc u nas, a zakljucci do kojih jc dosla zahtijcvali su mijcnjanjc shvacanj a gco]oskih odnosa u mnogim d ij elovima lacl asnje .lllgosiavije, pa i na regional nom planu. drllga velika geoloska ljubav bila joj je nasa sv im a draga meclvednica, i mozemo samo zal ili da svoje ogromno gco losko poznavanje mcdvednice nije st igla pri kazal i kao zaokrllzenll cjelinu. ali mnogo toga rekla nam je llsmeno, i ces to sll llain to bili poccci i putokazi ii nasim kasnijim istrazi ­ vanjill1a. za sve sio je llcinila, cesto zrtvujuci i sebe i na llstrb svog privatnog z ivoia, svi koji su.ie poznaval i oslal ce joj llv ijek zahvalni. svi je se raclo sjccamo i iz svojih s luelentskih dana i kasnije, radne cljclatnosti, a i sacla, kada jc vise nema, ona ce ostali sta lno pri s llina u nasoj geologiji, a svojim dacima i u src im<1. zalo ne ka je sla­ va i hvala nasoj uci teljici, gospodi profesor donati nedeli devidc. ivan gush': josip benic [n memoriam: doii;11;1 nedela dev[de llij3liograflja radova (sastav il a andrea hori~) 1. koci-lansky , v. & devlde-n edela, d. (1942): okamenjcni svjedoci pradavnog zivota na zemlji.znanje i radost, j, 3 17-32 1, z~greb. 2. devlde-nedela, d. (1954): izvjestaj prouca­ vanju stratigrafskih i tektonskih odnosa gornjc krede ii zagrebackoj gori ii j 95 2. goc1 .ljetopi s jugos 1. abd. wan. umjet. , 59 (1951 1952), 70-73, zagreb. 3. devlde-nedela, d. (1954): nalazi globotrunk­ ana ii mcdvcdni ci, zri nskoj gori , boki kotorskoj i okol ici budve (s ur la presence de genre globolrun­ cana dans la medvednica, z rinska gora, boka kolorska c t dans les env iro ns de budva). geo1. vjcsnik , 5-7 ( 1951 -53) ,299-3 15. 4. devlde-ne dela, d. (1956): 0 proucavanlu kredc na sjevernim pad inama medvednicc.ljetopis jugos !. akad. wan. umjet. , 6 1 ( 195 3), 325-328, zagreb. 5. devlde-nede la. d. (1957): znacenje globotru­ nkana za rj cshvanje nekih st ratigra fskih problema u ju gos la viji (signification des g lobolru llea nic1es pour cert ains problcllles st ratigraphiques cn yugo­ slavi ac).1 i kongr. geo1. jugosl. , 134-154, sarajevo. 6. dev lde-nedela, d. ( 1957): una tipiea serie d i copcnura: il lias della jugos lav ia cos ticra. rivol. industr. , 5/60, 45-47, milano. 7. devld e-nedcla, d. (196 1): di e krctazischcn bildungen kroaticns (jugoslawicn) im sp iegel del' ncucstcn forschun gen. ann. ins\. geo!. pu b!. il ung., 49/3, 869-87 1, bud"pest. 8. devld e-ne dela , d. & po lsa k, a. (196 1): mastrihl kod bespelja sjcverno od jajca (sur la prese nce du maestr ichti en dans les environs de 13espelj au nord de jajcc en bos nie) .geo!. vjesll ik, 14,355-376. 9. mamuztc, p. & dev id e-nedela, d. ( 1968) : osl1ovlla gco loska karta sfrj, li st biogracl 1:100 000 k33 -7.il1sl. geo!. istraz., zagreb ( 1963), say. geo!. zavod, beograd. 10. dev ld e-nedcla, d. , babic, l j. & zu pan ic, j. ( 1982) : maslrihlska starost nisa vivod ille u zum ­ berku i kod ozlj a (zapadna hrvatska) l1a temelj u plan ktonskih foraminifera (age maest richtie n du flysc h de vivodina dans ic zumberak et cnviron s d'ozalj en croatie occidentale (yugoslav ic)).gco!. vjesnik, 35, 2 1-36. ii. devlde-nedela. d. & kochansky -dev­ ide, v. ( j990): neoschwageri llenfund in medved· nica-gcbirge (zagrebacka gora) (nalaz ncosvageri ­ na u medvedni ci (zag rebacka gora)).rad .iugos !. "ked. wall. umjct. , 449 (razr. prir. zi1"n. 24) , 29-34, zagreb. 12. babic, lj ., gusic, 1. & devldt-ne dela , d. (1973): scnonski krsn ic i na mcdved lli e i i njihova krovina (senoni an breccias and overlyi ng deposits on mi. medvednica (northern croatia)).geo 1. vjes­ l1ik, 25 (1 971), 11 -27. 13. polsa k, a. , devid e-nedcla , d , turnsek, d. , gusic, i. & 13enic, j. (1978): 13i ostrat igraj'ski od nosi grebenskih, prigrcbenskih i bazenskih nalaza gornje krede u podrucju donjcg oresja, s 1 medved­ !l ica (b iostrat igraphy or upper cretaceous reef, sub· ree f and bas in deposits at donjc oresje, mi. medvedl1 ica, l10rth croatia).geo!. vjes l1 ik, 30/1 , 189197. 14. polsa k, a., drag ic evtc , i. , to mi c, v., devlde-ned ela , d. & bentc, j. ( 1982): tck­ tonska i pa leogeograi's ka dinam ika u rubnoj zoni jad ranske ploce; primjer kredno-palcogenskog kom­ pleksa lajce (tectonic and paleogeographic dynam­ ics in the marg inal zone o f the adriati c plat e; an example of cretaeeous-pa leogenc bauxi te·bearing arcn of jajcc) .10 jub. kongr. gco!. ju gos!. , 1, 605 623, budva. geologia cro;uica -19/2 geol. c roat. 49/2 1343 -344 1 zag reb 1996 a conceptual approach to the exploration and development of hc fields at the continental shelf bori s a. nikitin ', a le xandre 1. gritsenko' a nd evgue ni v. zakharov' proceed ings the subsurface of the russian seas continental shelf con tains morc than 45% o f the initial sum mary resources ( is r) or hydrocarbons (hc) or ihe wo rld ocean shell'. oul o f ihe 10lal he isr al ihe she lf or ihe russian federation seas , gas const itutes 55 .6%, and o il 38.8%. the reser ves arc predom inan tly in the ca te­ gories c:. d i and d2, the explored reserves or gas con­ sti tute less than 10% , and of oil less than 4%. despite ihis, 26 fi elds have already been discovered . exploration and development of he resources at the shelf compared with adjacent on-shore arcas, is charac­ ter ised by the significantly higher costs. tn such col1cli­ li ons, the in crease of scientifi c ancl techno-econom ic su bstantiation of prospecting, survey and development is or trcmendous importance. the main objectives, are : • defi nilion o r optimal hc resources (i n le rms or geo­ logical s truc ture, concentration and a rea l di s tribu­ lion); • determ inat ion of zones and he pools that are techn i­ ca lly access ible, economically effec tive and ecolog­ ica lly suitable 1'01' explorat ion and development. due to the fact that the concept was worked out for ihe poorly st udied and unevenly explored shel r of ihe russian seas, it is necessary to s trictly follow the prin ­ ci ples be low: • analogy, i. e . wh e n the inves ti gated reg ion of the water area over the whole section of sedim entary de pos its, o r it s separate part s , is compared to the geo log ica ll y s imil a r offand on -shore region wi th provcn industrial oil and gas bearing ability; • predic tion in the s tudi ed reg ion of the ne w hc fi e lds of some de fin ite phase type, concent ration of resources and o il , gas and condensate reserves and the ir produc ing capacit ies; • est imation of economic effic ie ncy or prospecling­ explorat ion works at the prospective st ruc tures, and economic viability of th e explored edge-o ff-shore and ma rine o il and gas field deve lopment respec­ tive ly, to de fin e the feasibility of cont inuati on of such works in the specific regions and zones; i jsc "gazprom", moskovskaya oblast, moscow, ru ssia. 2 vn ii gaz, p razvi lka. moskovskaya oblast, moscow, ru ssia. • comple x comparati ve analys is of s tructures and fie lds in order to se lect the rational directions and priorit ies of localism ion and developme nt ; • de fin ing the temporal s trategy and tac ti cs o f these works taking into accoun t the prog ressive me thods of us ing the improved and pe rfec ted technical means and technologies. the off-shore of the russian federation is subdi vid­ ed into 3 regions, according to the poss ibil ity for com­ pleted works lip to ihe year 2030: i. the shore shelf of the pechora and bare llls seas and the tazov and ob bays; 2. the deeper shelf of the bare nts sea, southe rn part of the kara sea, south-western part of the laplev sea, and the okhotsk and caspian seas she l f; 3. the shelf of the nonhe rn part o r the kara , be ring and laplev seas. on the basis of comp lex a nalysis the foll owi ng regions are given pri o rity fo r pros pecting and expl o­ ra tion: the pechora sea shelf and southern shore part of the kara sea. analys ing the techno-econom ic parame­ ters of s tudies of the he fi e lds in thc various seas, it became appare nt that it is most feas ibl e to begin devel­ opment of the fie lds on the pechora and kara seas shelf. the first priority regions of developmen t. are the eas tern part of ihe pechora sea she ll' (prirazlomny o il fi eld) and marine continuation of the nurin and nijne messojaha bars at the she lf of the kant sea, w here there is a hi gh co ncentration of provc n reserves and predict ed he resources. to deve lop off-shore hc fi e lds in the spec ified regions, icc-proof s ta ti onary platforms arc needed for a ll year round ope ra tion. as yet there are no suc h plat­ fo rms in russia. however thcir e laborat ion is unde rway at the converted milital)' enterprises. it is pl anned to use not only foreign, but al so domestic icc-proo f platforms, a nd the off-shore par t o f the kharasavei a nd kru zc n­ shtc rn field s should be explorcd by ho ri zont al drilling from the shorc. such a method of deve lopme nt is possi­ ble and also for the shore-marine fi e ld s in the ob and tazov bays. the respect ive works can on ly be unde rtaken on the basis of the highly product ivc technique and technolo­ gy, meeting the demands of both the rational usc of the subsurface, and the environmen tal protection require­ ments, while effective ly combining both budget and non-budget sources of finance . taking into account the fact that the speciric share of oil and gas in the fuel-energy complex of the russian federation will grow in the immediate future, the prob­ lem of prospecting, exploration, construction and oper­ ation of new off-shore oil and gas fields is going to be very rea l. tactically, marine prospecting works should be undertaken on a large scale. this will provide, [irstgeologi:l cro:l1ic:l 49/2 iy, timely preparation of the obj ects for succeeding studies; second ly de termining the areas, in wh ich it is feasible to obtain licenses fo r exploration and develop­ ment, it wil! also meet the terms of the relurn all invest­ ments. the ma in principl e in exploration and produc­ tion of oil and gas of the arctic seas shelf will be the attraction (vi a tender) of a wide spectrum of domestic and foreign investors (while maintaining national in ter­ ests), and their involvemen t in the domestic mar ine geo logical and processing complex. hughes et al..indd 1. introduction core-based information on the rudist species has significantly assisted the development of a threedimensional depositional model for the shaybah field, and is currently impacting its development strategy. as horizontal development wells are drilled, however, additional depositional facies control is required, and this necessitates more detailed studies on the environmentally-indicative biocomponents. cores collected during the exploration and development phases of carbonate reservoirs provide very important palaeontological, sedimentological, petrographic, diagenetic and petrophysical information. as plugging and slabbing often damage the cores, the original rudist fabric is often obscured and may cause inaccurate interpretations of the depositional environment. rudist fossils characterise much of the shu’aiba, and the distribution of various species is directly associated with computerized tomography reveals aptian rudist species and taphonomy geraint w. hughes1, shameem siddiqui2 and roy k. sadler3 the depositional environment. in an attempt to assist the delineation of various reservoir facies of fullbore formation microimager™ (fmi) logs in uncored horizontal development wells, the macrobiofacies of vertical cores have been calibrated with computerised tomography (ct) scans and fmi logs (hughes et al., 2002). the hydrocarbon-rich shu’aiba formation reservoir of the shaybah field is of lower aptian age. the formation consists entirely of carbonates that were deposited as an extensive blanket on the arabian platform (sharland et al., 2001, fig. 3.31). the rudist facies that form the focus of this contribution developed on the southern flank of an intra-shelf basin and were responsible for the lateral differentiation of an earlier open platform facies into lagoon, rudist bank complex and open marine regimes (hughes, 2000, 2001). comprehensive palaeontological and sedimentological studies of the intensively cored field have revealed a depositional history that is associated with the initiation and subsequent development of a rudist-rimmed platform. 2. computerised tomography (ct) a ct-scanner measures the attenuation coefficient of a material. the attenuation of the energy in the x-ray beams is related to the electron density and atomic number of the materials present in the object being scanned. at relatively high x-ray energies the attenuation coefficient becomes mainly a function of the electron density and the latter is a function of the core bulk density (porosity, grain density, and fluid saturation) and lithology. in this study a test slice thickness of 1 cm was used and image slices were stacked to generate a full 3-dimensional image of the core using software such as avs–express or opendx. ct-scanning offers the advantage that the data are stored for any future use unlike the cores, which become difficult to use after slabbing and plugging. ct-scanning is increasingly applied for non-destructive core characterization using core description, core quality assessment, lithology identification and for quantifying lithological heterogeneity. ct-scanning is also used to address reservoir scale-up issues, matching of conventional core analysis and log analysis data geologia croatica 57/1 67–71 2 figs. zagreb 2004 key words: computerised tomography (ct), formation microimager (fmi), rudists, lower aptian, shu’aiba, shaybah, saudi arabia. 1 saudi aramco, box 10646, dhahran 31311, saudi arabia; e-mail: geraint.hughes@aramco.com.sa 2 saudi aramco research & development center, box 62, dhahran 31311, saudi arabia; e-mail: shameem.siddiqui@aramco.com 3 saudi aramco reservoir characterization department, box 1825, dhahran 31311, saudi arabia; e-mail: sadlerrk@aramco.com abstract computerized tomographic (ct) scans of cored carbonates from the lower aptian shu’aiba formation reveal clearly defined rudist profiles. formation microimager (fmi) logs from the equivalent cored wellbore also display images related to the rudist content. various rudist species can be identified in the cores and provide a key to the identification of the ct and fmi rudist images. as certain rudist species preferentially occupied different environments during the early aptian deposition of the shu’aiba formation carbonates, their recognition in the cores, ct and fmi images can be used to assist determination of palaeoenvironments, lithofacies and reservoir facies. this new ability to identify rudist images in fmi logs in uncored development wells can be used to extend depositional facies models into uncored parts of the hydrocarbon reservoir models. 68 geologia croatica 57/1 69hughes, siddiqui & sadler: computerized tomography reveals aptian rudist species... (mostly bulk density and porosity) and broad mineral classifications. the particular applications of ct as a reservoir characterization tool include classification of heterogeneity; identification of lithology and broad mineralogy, sand–shale sequences, vugs, fractures and high-density mineral inclusions; measurement of bulk density and porosity; core-to-log depth correlation; visualization of mud invasion; evaluation of damage in unconsolidated cores, etc. apart from core characterization, ct is used extensively to visualize and quantify hydrocarbon fluid displacement in cores in simulated laboratory experiments to determine residual oil saturation, to evaluate trapped porosities, to visualize and quantify gravity and viscous effects, etc. detailed reviews of the application of ct in various coreflood experiments can be found in the literature (kantzas, 1990; siddiqui, 2001). application of ct technology towards palaeontological use is limited, but examples already include investigations into vertebrate morphology (rowe et al., 2001) and algae (torres et al., 2003). rudists are extinct bivalves that form palaeoenvironmentally and stratigraphically important components of the shu’aiba carbonates. as rudists are made of denser materials than the main ingredients of the rock, a high-density threshold was applied to the ctderived data that resulted in figs. 1 and 2). to illustrate the use of ct, a 85.34 cm (2.8 foot) cored section containing large elevator rudists has been scanned and photographed. a series of transverse ct scan images were generated at 7.62 cm (3 inch) spacing (fig. 1), in which low density areas are illustrated in cool colours black to blue, indicating densities up to 2 g/cm3. these slices are arranged in order down the core, in columns commencing at top left and terminating at bottom right. higher density parts of the core, between 2.0 and 2.65 g/cm3, are displayed as warm colours ranging from green through yellow, orange to red. as most of the core consists of packstones and wackestones, the average density varies between 1.7 to 2.2 g/cm3. these slices were used to generate a synthetic vertical section through the core (fig. 2). the large rudist at the base of the core in fig. 2 consists of a yellow core with a green margin, depicting a moderately dense rudist wall enclosing the rudist chamber filled with denser calcite. in the upper core, the slice at seven positions below the top of the section displays a dark blue area in the centre, surrounded by a thin yellow rim, and represents another elevator rudist with an unfilled chamber. 3. imaging well bore walls – fmi logs the fullbore formation microimager™ (fmi), records an array of microresistivity measurements from 192 receivers on eight pads mounted on four orthogonally placed caliper arms. the spacing and position of the pads provides 80% coverage of an 20.32 cm (8 inch) diameter hole and a resolution of 5 mm. the fmi yields a continuous, high-resolution electrical image of a fig. 1 ct images of a 85.34 cm (2.8 ft) section of core, together with a density calibration scale in which higher densities are displayed in “warm” colours, and low densities as “cool” colours. the circular images represent ct slices through the core. images are arranged in rows in descending order down the core, commencing in the top left corner and terminating at the bottom right corner. the dense, calcite-filled rudists are displayed as orange/yellow shapes, such as in the lowermost right circle. rudists with unfilled right valves are displayed as black shapes, such as in the circle above that in the lower left corner. 68 geologia croatica 57/1 69hughes, siddiqui & sadler: computerized tomography reveals aptian rudist species... borehole, and therefore complements whole cores cut in the same well. if the image is of sufficient quality and calibrated against the core, it can provide a continuous survey of the formation in places where core was not cut, there was no core recovery, or when a core has been damaged through handling, transportation, or plugging. in the case of the subject of this paper, the fmi images provide a third perspective to the core and ct scanned images of the vertical distribution of macrofossils in the shu’aiba formation. 4. rudist biofacies and palaeoenvironmental significance seven rudist species are known from the shu’aiba formation in saudi arabia based on analysis of cored wells over the field. each of these rudist species, and growth style, are clearly identifiable in side profile, and their preferred ecological preference in relation to the rudist bank complex has provided a useful method of determining sediment type, provenance and associated reservoir quality prediction. the rudist complex includes the recumbent species offneria murgensis masse that is typically found on the crest of the bank, and represents adaptation to high-energy conditions with no ambient sediment deposition. the presence of pallial canals in the wall of this caprinid species probably permitted rapid growth in a high energy environment with sediment bypass, and its later fragmentation into coarse, highly porous carbonate sediments has significantly contributed to the subsequent development of good reservoir facies within the shaybah field. oedomyophorus shaybahensis skelton was adapted to the high rate of coarse sediment deposition on the lee side of the bank. the most extensive and well-developed rudist biofacies is that containing the elongate conical, caprotinid elevator species glossomyophorus costatus masse et al. this species is smaller and less robust than o. shaybahensis, but developed in response to sediment accumulation in a moderately low energy environment at a greater distance lagoonwards from the offneria bank. the sediment forming the supportive matrix of this species typically includes a high proportion of finely comminuted offneria debris and provides high porosity and permeability in the reservoir. rare specimens of the long, thin, pencillike caprinid elevator species offneria nicolinae skelton & masse are present in this biofacies. forming a very narrow flank lagoonwards of the above biofacies is a fine-grained belt occupied by the stubby, conical, caprotinid elevator rudist agriopleura sp. cf. a. marticensis skelton & masse. the left valve is not visible laterally because it lies countersunk within the flared open end of the right, or fixed, valve. this species displays an extensive distribution in the uppermost layer of the shu’aiba formation at shaybah, where it alternates with the related, but elongate, form agriopleura cf. blumenbachi (studer) (hughes, 2002, 2003). on the outer flank of the rudist complex lies the large, conical elevator rudist horiopleura sp. cf. h. distefanoi (douvillei), that adapted to moderately high rates of sedimentation derived from the tidal backwash of sediment from the adjacent rudist bank complex. recently, exceptionally large specimens of the rudist offneria murgensis were discovered in the outer flank position, where they display a vertical, growth position indicating an elevator mode of life. identification of the rudist species therefore provides an important guide to the palaeoenvironment. figure 2 displays a section of slabbed core containing the elevator rudist offneria murgensis together with its ct scan images in transverse slices and vertical composite. the large rudists present in the study core were first interpreted from the ct scan, as the core tube was not open at that time, but enclosed in a plastic sleeve. their large size and elevator attitude suggested that identification as oedomyophorus shaybahensis and a back-barrier palaeoenvironment was supposed. when the core was opened and slabbed, the larger right valves of the rudists were seen to bear thin sub-horizontal platform structures called tabulae, and the identification was corrected to offneria murgensis. this was a significant discovery, as o. murgensis had not been seen in an elevator growth form in any previously examined cores. according to dr. p.w. fig. 2 core photograph of shu’aiba carbonates with the elevator form of the rudist offneria murgensis, together with two synthetic vertical ct scan images of the same core. see density calibration scale in fig. 1. the ct image on the right is in the same plane as the slabbed core; the ct image on the left represents a vertical slice normal to the slabbed plane, and has missed the rudist. 70 geologia croatica 57/1 71hughes, siddiqui & sadler: computerized tomography reveals aptian rudist species... skelton of the open university, united kingdom (pers. comm.), it is not unusual for certain species to adopt an elevator growth form instead of recumbent, whenever environmental conditions are appropriate. at the location of the study core, a high rate of sediment deposition is interpreted on the fore-slope of a rudist bank in which only the rapid growth capability of o. murgensis enabled survival. whereas most of the lower aptian rudists display sufficiently different profiles to enable their identification in ct scans and fm images, it must be admitted that differentiation between o. murgensis and o. shaybahensis cannot be established with confidence. 5. conclusions rudists appear as high-density bodies scattered through the ct scan and fmi images of the core, and can be used for species identification, taphonomy and therefore palaeoenvironmental interpretation. the elongate high-density (from ct) and high resistivity (from fmi) shapes represent an elevator rudist (fig. 2). the dimensions originally suggest that the specimens could represent the robust back-bank species oedomyophorus shaybahensis, but it was difficult to explain the very low density of the inner part of the left valve. on examination of the core, it was found that the images were, in fact, of a new elevator growth habit of the robust caprinid offneria murgensis, and that a fore-bank depositional setting is represented with its associated high rate of sedimentation. further examination revealed that the low-density internal character results from the absence of infill material owing to the baffle compartmentalization created by the transverse septulae. the vertical orientation of the rudists in the core further indicates that the cored assemblage represents an undisturbed assemblage. the three-dimensional vertical interpretation of the succession of horizontal ct scan images further reveals the torsional aspect of the rudist valves, this being an aspect of elevator-mode offneria murgensis that has, until now, never been observed in this species. the inclination of the rudist valves has the potential for revealing the direction of predominant water current direction, as flume tank experiments have revealed (gili & labarbera, 1998). elevator rudists would be, as part of an optimal filter-feeding strategy, preferentially inclined away from the predominant direction of water flow. one important advantage of the use of ct scans is that a three-dimensional view of the rudists is available for study, as this primary fabric is often destroyed when friable cores from the shu’aiba are slabbed for internal description. the three dimensional aspect also has the advantage of revealing rudists that would never be visible in unexposed core surfaces, and thereby enable a taphonomic and palaeoenvironmental interpretation to be made on a higher number of rudist individuals than would normally be visible for study. the advantage of the present approach lies in the ability to (1) calibrate the ct scan images with the core, and (2) calibrate the fmi images with the ct scan interpretation, thus enabling interpretation of the depositional environment, depositional and potential reservoir facies from fmi logs of vertical and horizontal development of noncored wells. further work is required to define all other shu’aiba rudist species in terms of their ct and fmi profiles. acknowledgements the authors acknowledge the permission given by saudi aramco to publish the information here presented. the contribution was presented at the 6th international congress on rudists held in rovinj, croatia, in september 2003. the constructive comments by reviewers robert w. scott, thomas steuber and jörg renner were heeded by the authors and have assisted in improving the quality of this contribution; their assistance is gratefully acknowledged. in addition, thanks are cordially given for the continued provision of friendly and informative advice by dr. peter w. skelton of the open university, united kingdom. 6. references gili, e. & labarbera, m. (1998): hydrodynamic behavior of hippuritid rudist shells: ecological consequences.– in masse, j.-p. & skelton, p.w. (eds.): quatrième congres international sur les rudistes. geobios, memoir spécial, 22, 137–145. hughes, g.w. (2000): bioecostratigraphy of the shu’aiba formation, shaybah field, saudi arabia.– geoarabia, 5, 545–578. hughes, g.w. (2001): biofacies of the shu’aiba formation, shaybah field, saudi arabia.– saudi aramco journal of technology, summer 2001, 1–19. hughes, g.w. (2002): agriopleura species as depositional cycle indicators in the shu’aiba formation of saudi arabia.– in: vlahović, i. & korbar, t. (eds.): abstracts and excursion guidebook. sixth international congress on rudists, rovinj, september 29–october 5, 2002, 27. hughes, g.w. (2003): agriopleura morphotypes of the lower aptian shu’aiba formation of saudi arabia.– geologia croatica, 56/2, 133–138. hughes, g.w., siddiqui, s. & sadler, r.k. (2002): computer tomography and fmi interpretation of rudist taphonomy and reservoir facies in the shu’aiba formation, saudi arabia.– in: vlahović, i. & korbar, t. (eds.): abstracts and excursion guidebook. sixth international congress on rudists, rovinj, september 29–october 5, 2002, 28. kantzas, a. (1990): investigation of physical properties of porous rocks and fluid flow phenomena in porous media using computer assisted tomography.– in situ, 14, 77. 70 geologia croatica 57/1 71hughes, siddiqui & sadler: computerized tomography reveals aptian rudist species... rowe, t.m., colbert, m., ketcham, r.a. & owen, p. (2001): high-resolution x-ray computed tomography in vertebrate morphology.– journal of morphology, 248/3, 277. sharland, r., archer, p.r, casey, d.m., davies, r.b., hall, s.h., howard, a.p. & simmons, m.d. (2001): arabian plate sequence stratigraphy.– geoarabia special publication, 2, gulf petrolink, bahrain, 371 p. siddiqui, s. (2001): application of computerized tomography in core analysis at saudi aramco.– saudi aramco journal of technology, winter 2000/2001, 2–14. torres, a.m., christensen, a.m., masters, t.e. & ketcham, r.a. (2003): from ct scans of embedded ivanovia to models using rapid prototyping.– palaeontology, 46/4, 839–843. manuscript received march 13, 2003. revised manuscript accepted may 04, 2004. 72 geologia croatica 57/1 geol. c roat. 49/2 347 zagreb 1996 ahslmcl note evaporite diapirism in albania and its influence in the thrusting process tela velaj the upper triass ic evaporites have a wide ex ten ­ s ion in the o rogen ic zones of the con tinental margin (throu ghout the albanidcf-iclenide-dinaridc tectonic assembly), and there fo re across the adriati c p latform. they constitute the substratum of all the above tectonic zones, playing a s ignifi cant role both in the s tructural model and in aiding the thrusting process. genera lly, these evaporites consis t of inte rcalations o r anhyd rite , gypsum , chlorites, dolomites, limestones, multicoloured c lays e tc. occasionally volcanic matter, e .g. bipiramidai quart z c ryslals arc encounte red. the age of the evaporites is upper triass ic, and is verified by palynologica l de te rmination with th e presence of species such as: call1el'osporiles, parillosporifes, veri­ cosporifes, o\'o/ipo/is, zonalisporifes e tc. in albania, the evaporite di api rs may be encoun­ tered in three tectonic settings: 1. evaporite diapirs that have erupted ac ross or via reg ional fault plan es associated with a marked over­ thrust westwards and whi ch border the diffe rent tecto­ nic subzones o f the ionian zone. a) in the wes tern front of the inte rnal subzone (berati belt ) a regional ovenhrusting fault o f 20-30 km magni­ tude can be traced. thi s ove rthrust occ urs because of the presence of a large diapir sheet whi ch ou tc rops in depressional sec to rs such as dumrea, zavranona, etc. there arc suffic ient data (mainly seismic) showing that some carbonate s truc tures of western units oeeur beneath this overthrusting tectonic struc ture. oit and gas tnslitute. r-icr, al ban ia. proceedings b) in the western fron t o f the ex ternal subzone «:ika zone) a reg ional overthrusting fau lt exists, whic h dev i­ ates northeastward in its northern pan. the orogen over­ thru sts through thi s fau lt and the diapiric body to th e apulian platform 50-100 km and in this way hides a transiti ve (or platform·orogen ic) zone of inte res t for explorat ion. c) t he kruj a tectoni c zone a lso has anothe r thrust fault in its weste rn frol1l covering pan of the southe rn adriatic basin. it cuts diagonally the s tructural lines and is a lso associated with evaporite diapirism. 2. evaporite diapirs which have erupted via local fa ult s or the individual structures of the middl e ionian subzone, such as delvina 's, bashaj's e tc. the thrusti ng magnitude of this diapir sheet is of 8-1 0 km a ll ow ing masking of new structura l units. 3. evaporite diapirs which have erupted nearly verti­ cally in the centre of the carbonate anticline struc tures, such as navarica's, jan icati 's, kardhiqi 's etc . th ese diapirs generally have a cupola form. in the inte rnal zones the evaporites appear in tecto­ nic wi ndows of cupola shape (c.g. korabi zone, albani a and radck, macedonia). in th is case they are in contac t with the kruja oligocene fl ysch and upper cenomanian rudi st carbonate. thi s led to the sugges tion that the korabi evapori tes have 1.0 be lon g to the kruja zone, which shows a global allochthony or the inte rnal zones and subduction of the external ones. 3-ir geologia cro:llica 49n geol. croat. 49/2 145 1531 12 figs. 1 1 zagreb 1996 system architecture for 3d gravity modelling franjo sumanovac ', [po l. ritsema' and bert h. bril' key word s: gravity modelling, com plex models, soft­ ware archi tecture. abstract a fl exi ble so ft ware architecture fo r grav ity modell ing is cs i:lb­ lished and the ad vantage is discussed of hav ing seve ral alternative programs 10 handle complex 3d models. the flexible architecture consists of four pa ris. implcmclucd in a d istributed computer environ­ ment : (ile three-dimensional model bui lders and v isual izers (gocao software. version 7.0), the model representation translators (coca o software or geomod sonwarc), the forward simulation algorit hms of gravimetric data ('lpp lyi ng talwan i-ewing and gthzeluhmcye r me thods in the finite-c lement representation class), and thc invcrsion (mode l upd;lt ing) sc heme manager based on the co rde ll li enderso n in ve rsio n proccdure. a good so ftware architec ture shou ld at least keep the modcl build ing and updating so rt ware separate from the forward simu lation software. inversion schemes can then bc real ized by commun icat ion be tween thc two part s of software. several synthetic cascs arc shown 10 demonstrate the lise and the capabi lity of the architecture and mcthods appli ed. the gravit y fie lds of com plex 3d models, i.e. overhangi ng and non-overhangi ng sa[1 domc~, are sim ulated. the gravimet ric anomalics for both cases have very simil ar shapes. gravi ty modelling can d istingu ish between these, because the ex is ting mass di fferences result in anomal y d iffe rences bot h for surface profiles and x-sections. the capabil ity o f (he inver­ sion procedure is a lso show n in the d ise llssed synt hetic case. t he inversion manager is able to creale thc global struclural forms repre­ sented "" a horiwn with constant density contrast (a two-l aycr model) from residual gravity anomal ies. l. introduction gravimetry is applied in hydrocarbon, groundwater, minera l and geotechnical studies. in hydrocarbon stud­ ies , grav it y modell ing is often used on a regional scale to deli ne3le [he basin and the main structural characte­ ristics assoc iated wi th the ta rgets. on a local scale it is used in struc tural inte rpre ta tion to de fine o il and gas struct ures. however, in de tailed reservo ir and produc­ tion modelli ng gravimetry is not fully ut ili sed , although a lot or d iffe rent da ta sc ts obtained by surface and bore­ ho le measurement s can be used to more precisely con­ strain ihe interpreted structures (fig. 1). kljucne rijeci: gravi metrijsko modeliranje. kolllpleksni modcl i, arhitektura softvera. sazetak razvi jena je clasli cna arhileklu ra so ft vera za gravi mctrijsko model iranje, ie su izlozenc prednosli programa koji mogu obradivati kompt eks nc 3d mode lc. soft vel' se sas toji od cetiri d ijela, koja su ugradcna u odgovaraj uce kompj utorsko succljc: programa za obliko ­ vanje i prikaz iva nje trodi mcnzio nal nih modc la (goca o soft ver, vcrzija 7.0), programa za fo rmaliranje i izmjenu podalaka izmed ll razlicitih so ftvera (gocad soflver iii geom o d .~oftver), programa s ugradenim al goritmima za racunanje g rav imc lrij skog djelovanja (talwani -ewing i go tzelahmcycr metodc u pod ru cj ll metoda konacn ih clemenata) i prog rama zll g rav imc trij sku inve rzij u tcme­ !jcllog na corde ll-hendersonovoll1 postu pku inverzijc. smat ra se bo ljom arhit ekturom drza ti odvojcn im so rlvc r za obl ikovanje i iz mj enu modcj a od so ft ve ra za racunanjc g ravim elri­ jskog djelovanja, a posl upak inv erzij e sc os tvaruje razmjcnom podataka izmedu la dva dije!a. na si nlc tskim pri mjerirna izloze na j e upo trcba i mog ucnos ti razv ij cnog son vera i primijcnjcnih metoda. prika za na su teo re lska gravimel rijska polja solnih doma, kojc predslavljaj u siol.c llc gco loskc modele. gravi melrijskc ano ma lijc ov ih modc la irnaj u vrl o s lic ne obrise, ie je jedino gravimetrijski m modelir'lnjem moguce medu so­ bno razlucit i ove mod ele zbog razlic itog rasporcda masa, koje uzrokuju razlici te vrijednosti anomalija, k:lko za pov['s inske profi le. tako i za x~sekcij u . mog ucnos ti pos tu pka invcrzijc su prikazane na prilozenom si ntetskom primjeru. pos tu pko rn inver.djc dobiven a je slruk tu ra po gra nie i s razlikom gus toce, od nos no za jed nos tavni dvoslojni model, na temelj u rezidualnc gravimclrijske anomalijc. in order to use au available data sets it is important 10 have modellin g soft wa re whi eh sho uld be a t least three-dimcnsionallo accurately describe [he subsurface propci1ies in space and enable realistic simulat ions to be form ul ated . it shou ld be ab le to process comp lex and deta iled three-dimensional models, as fo r surface mode­ ll ing. therefore for borehole modelling, applying gravi­ metr ic a lgorithm s to boreho le measurements, can aid calculat ion of the e ffec ts o f both surface and boreho le local ions. the la tte r arc very impo rt an l in the produc­ tio n phase to constra in struc tura l inte rp rela tio ns of reservoi rs on a local scale. it must be emphasized that high-quality gravi ty data acqu ired by high-precision instruments shou ld be availi university of zagreb, facul ty of mining, geology and petroleum engineering. pi erollijev a 6, hr l 0000 zagreb. croa! i:l. 2 tno ins!itll ic of applied geoscience, schoemakers traat 97, 2600 ja del ft, thc nethcrlands. gravity modelling , sasinmld i prospect models i • reservoir modets i production models . e xploration p roduction fig. 1 tile effec t of gravi t j modelling on buildill£ o f the <li llcrcll l geolog ical models ill prac tice from exploratiol110 product ion. able for m lc":ccss rul g ravity modelling. on the local sca le hi gh-reso lut ion g ravi ty dat<l shou ld be used for g rav ity mode lling or s mail com plex st ructures . data spac ing depends 011 the illodel c le men t size, but it al so affects the precis ion or the reg ional -res idu<ll sepa ration, wh ic h is a vc ry c riti ca l s tep in gravi ty interpre tation fin d s ig­ nifican tly controls the final resu lts. thi s pape r di sc ll sses a fl exible so ft ware archi tecture and the advantagc or having several programs to handl e complex three-d imensional modcls. 2. g ra vlty modelling t he proble m or g ravi ty interpreta ti on involves the solutions of bot h the forward and inverse problem. t he d irect problem or the forward modelling dea ls with the theore ti cal c al c u lat ion or the g ravi ty a no ma lies for a g iven model. the inverse problem o r g rav it y in vers ion deals wit h the calcu lation of structural fo rms fo r g iven g ravity a nomali es . both prob lems can be solved by ll s ing two different approaches, th e s pace dornain approac h and th e freq uency domain o r spec tral appro,l(.;h. the "space domain mcthods " ll sing a vo lulll e inte­ g ral , are frequently applied ror thc forward calcu lation of thc g ravitat iona l attraction of arbitrary shaped bod­ ies. in o the r te rm s, these arc ana lytica l techniques to cal c ul a te th e g ravity fields of complicated mode ls whose geome try is approximated by a certa in number or small e leme ntary bodies, such lis horizontal lam inas, prisms, or po lyhe drons . tha t have analytical so lu ti ons ( fig. 2). ta i. wan i & ewing ( 1960) suggesled a method to cal culate the gravity anomal y of a three-dimensional a b body by the llullle rical integration or a sel of horizonta l polygona l laminae tha t approx imate the sh ape of the bod y. nagy (1966) sta ted a formu la 10 ca lc ulate the gravitat ional allraction o f a ve rti cal rectangular p ri sm. all ite rative method for calculation of the g ravitationa l all rac ti on, whe re the causati ve body is approximated by ve rtical pri sms. was sugges led by cordell & iien­ derson (1968) . the gravity effcel o f each pri sm cle­ men t is approxim a ted by the vcni ca l right -cylinder sou rce rormu la and the ve rti cal l ine-so urce ["orm ul a. botezatu et a l. (1971) sugges led the 1l1elhod for cal­ culation of the gravi ty erfect by dividing the body into s1l1all-si7.ed cubes. also m uf'ti ( 1973, 1975) presenlcd approximation rormulas ror a cube's grav ity field and a g ravity modelling scheme whic h uses cubes as building blocks. the method based o n the exact ca lcula tions of the grav ity and magne ti c anomalies of po lygonal prisms was presented by p lour:r: ( 1976). bi-iatt ac fl a ­ ryy a (1978) considered computer mode lling in g ra vi­ ty and magnetic inte rpretat ion us ing the solu tion of the d irec t and inve rse problems. three-dimensional in terac­ tive modelling in gravi ty anc! magne tics was sugges ted by gotze & lahmeyer ( 1988). they presenled the int e ractive modelling program where the body is con­ stru c ted from polyhedra of suitabl e geometry. the gravity c!l ec t of the homogeneous polyhedron is c~llcu ­ lated by tran sform ing the vo lume integral into a sum o r line integrals. the methods which lise fourier nna lysis be long to a second g roup " \vavc nu mbe r domain me thods". t hese methods conve rt the grav it y anomaly into fouri ­ e r series and prov ide for g r<lvity in version, com monly us ing the fas t fourie r trans form . deve lo pme nt of these melhods sta rted w ith park er ( 1973) and old­ enburgh (1974), who used fourie r trans fo rm ana ­ lys is o f the gravity anoma ly. the re nre a large number of methods belonging to this g roup, but only a rew w ill be menlioned here. granser ( 1987) useel fast fouri ­ e r transform and an exponent ial dcnsi t y~dept h func­ tion. lines ct al. ( 1988) ca rri e d out a coo perati ve invers ion 01 geophys ical dala. c ii enot & debe­ gl ia ( 1990) presented the me th od or de pth -mapping invers ion or gravity ;:h1d magnetic fi e lds. guspi ( 1992) proposed one r rt gravity inve rs ion me thod based on parkcr-oldcn burgh formulas. grav it y inversion us ing the rouri er transfo rm o r ot her techn iques leads to smoothing of the data because s uccessful convergence requires removal of the high­ frequency compone nts. therefore it can be successfully <lp pl ied in the g ravi ty model ling o f large a re as (i.e. bas in s tructures) but not in the cases of small complex / /:5\ /' \ / ""-. c fi g. 2 cross sec tiol1 or the booy represclhcd by vertical pri sms (a). cubic blocks (b), alld con­ tours (e). st1ll1anovac. rilscm;l & gril: system archi tect ure for 3d gravity modelling 147 inversion scheme manager i network i model builders i i data translators i i gravimetric i and visualizers and transmitters simulators structures (i.e. overhanging salt dome, overthrust, etc.). gravity illversion can be very useful in generating an overview of the study area and thereby enabling separa­ tion o j' prospective zones and direction of further research activity. the forward modelling can be applied in the cases of small comp lex bodies and it allows more detailed interpretation of the gravity data. besides, the inter­ preter can be more involved in the interpretation process applying a priori knowledge derived from th~ data acqu ired by other methods (seismic methods, the data from bore holes). 3. architecture different 3d models (velocity, geological, reser­ voir) that are produced by various model builders, arc not always accessible by gravimetric routines. typical ­ ly, models have to be exchangcd and rcformatted before the algorithms will work. a good open architecture can keep the model building and updating software separate from the forward simulation software and can realize inversion schcmcs by communication between the two worlds. thi s means that at any time, models of var ious re lated properties can be checked with different con­ strain ing data scts . it is also clear that the architecture applied is very oexible enabli ng a relat ively rapid easy change of the implementations on the subsystems very quickly. the flexible architecture, consisting of four parts, can be implemented in a distributed compuler environ­ mcnt (fig. 3): the three-dimensional model builders and visualizers, thc model representation translators, the forward simulation algorithms of grav im etric data, the inversion (model updating) scheme manager. 3.1. 3d model builders and visualizers two representations are typically used in 3d model builder programs, i.e. grid or finite clement representa­ tions (fem) and boundary representations (brep), each of them has advantages ror specific visualization and simulation algorithms. in this work, the connect ion has been established bet ween a three-dimensional fig. 3 software architecture . brep modcllcr (gocad) and several gravimetric pro~ grams operating on different fem representation s of the three-dimensional model. gocad is three-dimensional modelling software based on the "discretc smooth interpolation method" which is the centre of a new approach based on decoill­ position of lines into segments, surface into triangular facets and volume into tetrahedrons (mallet, 1989). gocad can be used very efficiently for modelling sur­ faces dcl'ined by various type data, and for exporting the data for the calculation processes. in the export process a transformation is needed in some cases. it is especially important that gocad can eas ily handl e complex structures such as overhanging salt domes and overthrusts. it also enables the easy calculation of syn­ thetic gravimetric data for such geological models. 3.2. model representation translators several transformation functions were needed and implemented in the dist ributed computer environment to exchange data from the model builder to the different gravimetric simu lation routines. the internal gocad modej representation, i.e. triangulated surface (brep) was transformed into two finite clement (fem) repre­ sentations, being horizontal contouriine slabs, and verti­ cal triangular prisms. this is realized using avai lable transformation programs in gocad or external pro­ grams such as geomod. the output is used by for­ ward and inverse modelling software. 3.3. forward grav imetric simulation algorithms two forward calculation algorithms have been implemented, talwani-ewing (using horizontal slabs) and gotze-lahmeycr (using vert ical prisms). in the talwani-ewing method the three-d imensional body is first represented by contours that arc then replaced by horizontal irregular n-sided polygonal lami­ nae. if the number of sides n is suffic ien tly large , the polygon can approximate the contour line as closely as desired. the gravi ty anomaly produced by each lamina can be calculated analytically at any external point. a contour line on the surface of the arbitrary shaped body at depth z below stat ion p (fig. 4) is replaced by an n­ sided polygonal lamin a of infinitesimal thickness dz (t alw ani & ewing, 1960). the gravity anomaly at 148 y x p ,l---------+ ------z y h g f contour at depth z fig.4 geometri c elements of the polygonal lamina used 10 calculate the gravi ty effect (a fter talwani & ewing, [960). station p. whic h is the ve rti cal compo nent of the g rav i­ tat ional a ttrac tion , prod uced by me ntioned polygonal lamina can be expressed as: g, = v dz ( i ) te rm v is ihe g ravi ty anomaly caused by the poly­ gona l lamina pe r unit thi ckness. v is expressed by the surface integral, but it can be reduced on two line inte­ grals (both along the boundary of the polygonal lam ina) and can be g iven by the expression: (2) where k is the un iversa l gravitational cons tant , p is the volu me de ns it y o r the la mina a nd z , y a nd r arc the cy l indrical coordinates (fig. 4). p ' is the projection of thc station p on the plane of the polygonal lam ina. a ft e r severa l transformations and substi tutions the fin a l expression for a gravity anomaly caused by poly­ gonal lam ina is: zcosil , }] ) pi2 + z 2 (3) geologia croalica 49(2 x y fig. 5 geomelry o f the etementary body used to calcu lme the gravity crrccl (after gotze & lahme yer, 1988). whe re pi:::::pllj. all terms (pi' yi' yi+i' cosch and cosy) can be e xpressed in xi and yi coordi na tes of the polygonal points. the tota l anomaly g, produced by who le body is expressed as: 'g, tota l = f dz '(4) us ing the afore me ntioned express ions the aut hors gave the ex pression sui tab le fo r programmi ng. w he re a ll terms arc given in x , y a nd z coo rdina tes of the polygonal points. the gotze-lahmeyer method to calculate the allrac­ tion of a homogeneous polyhedron al station p is based on the eval ua tion of the vo lume integra l. the gravity anomaly g(p), after derivation of the pot e nlia l with respect 10 the vertica l component z, is g iven by exprcs­ s ion: au fff a 1 tz (p) = g(p) = kp az (e) dv poly. (5) w here u(p) is the potential al s tat ion p, r is d is tance be tween p a nd dm (dm=pdv, clv= pdxclydz), a nd k is the gra vi tationa l cons tan t. correspo nd ing to the rele­ valli theories of vec tor ana lys is, a n equation is estab­ li shed where the surface integral has to be calculat ed fo r the w hole polyhedron sur face. a transformati on o f the coordinates syste m (into the surface oriented coor­ dinate system) is carried out to s implify the mathemmi­ cal expressions in the evalual ion of the surface integral. finally a conversion of the surface integra l into a linear in tegra l via polygon, which limits the surface, is carried out. sulll<l i iuv;i(:. riisc111<l & i3ril: systcl ll architecture for 3d gmvily mlxlclling 14 9 fig. 6 overhanging salt dome wilh gravity field at surface (a), which is detached as a map (b) . contour interval 0 .2 x i05m/s2, density co!l1rast t.p=-400 kg/m). the au thors also produced a final formula to calcll­ late the grav ity anomaly produced by the polyhedron , wh ich is suitable for programming. a subroutine has been published, written in fortran, 10 calculate ihe gravity effect of a vertical prism , infinite in the z direc­ tion with a triangle as the upper boundary. this elemen­ tary body, whose shape (geometry) is presented in fig. 5, ean be used to construct more complicated bodies. in th is case the gravity effect of the entire body would be expressed as a sum of the gravity effects of the elemen­ tary bodies. this s ubroutine was the second routine implemented for the gravity forward modell ing. the option, which uses the gbtze-lahmeyer method can be used to calculate the gravity effect of noncom­ plex (sim ple) structures. for computation of the gravity effect or complex structures, as for instance a salt dome (overhanging) or overthrust, the option using the tal­ wan i-ewing method should be used. 3.4. inversion scheme manager the inverse sc heme manager should support the inversion strategies. one approach is by a trial and error process, another by automatic (constrained) inversion. the cordell-henderson gravity inversion scheme is use rul to producc the first model, which is constrained here on a simp le two-layer model it is an iterative scheme based on the standard trial and error approach. the scheme consists in general, of threc aspects: construction of a simple start model , calculation of the gravity anomaly for a given model, and modifi cation of the model based on differences between calculated gravity anomaly and observed gravi ty anomaly. in the first step the gravity anomaly is digitized on a rec tangular grid . the interpreted body is represcnted by rectangular vertical prisms in a regular grid with a f1al top and bottom. the thickness of the prism elcment below the q-th grid point (station) tl.q for the starter model is es tabli shed by means of the bougucr slab for­ mula: t 1.q = bgobs,q 8=_1_ 2nkp (6) iso geolog ia cro;llica 49n fig. 7 cylindrical ~alt dome with gravity field ,ii surface (a), which is dclached as a 1ll;ip (b). contour inlcrval 0.2 x i0 5m/s2, dcm;il y contrast 6p=.400 kg/mj . where k is the g ravitat ional constan t, p is the density, goo.,q is the observed gravi ty at q-th station. the authors sugges ted the following relationsh ip for the next modi ­ fi cation or improvement of the model: t t (g".,q) n+i ,q = n,q g-­ calc ,n,q (7) where j1 is number of iterat ion and gc~lc.n.4 is calculated gravity value below q-ih station at n-th iteration. the prisms are thcn approximated by vertical cyl in­ ders si nce the fo rmu la calcu lating the grav ity e ffect o f the ven ical cylindcr is much simpler and consumcs less calculati on tim e. the goodness of fit is expressed in terms of the root-mean -square error (rms error). how­ ever, also the largest error can be used. the inversion scherne described is used for obtain­ ing the initial model of a two-layer structure. the result or more complex models (based on ot her da ta) can be verifi ed by using fo rward modelli ng techniques <.i nd adjusted by ll sing the trial and error approach. 4. cases two synthetic cases (o verhanging and non-over­ hanging salt dome) are shown as an example or thc use or architecture and the capability to simulate the gravi­ mct ric fields fo r complex mode ls (figs. 6 and 7). the mode ls and the gravimet ric fields a t the surface arc shown us ing gocad software ror bo lh cases. the erfect of the difference in shape of the bodies is clearly visible (figs. 6 and 7). the g ravity anomalies at the cent res of the sal t domes arc -3 .6 x 10-5 111 / s2 for the overhangi ng and -4.6 x 10·5m/52 fo r the cy lindrical dome, respect ively. both surface gravimctric anomalies have concclli ric shapcs, but on the surface gravity profi les (fig. 8) the differences in gravity attraction arc ev ide nt , a lthough they decrease with the increase or the distance [rom the centre or domes. calculated gravimet ric data 1'01' x-sec­ tions just outside the cy lindrica l and overhanging salt domes arc shown in figs. 9 and 10. fo r cylindrical body, the isoli nes arc almost ve rl ica l for th e fi rst 500 metres, and fo r overhang in g structure, thc gradient increases faste r wi th dcpth. the x-section of d iffe ­ rences in grav ity attract ion bet ween dom cs arc shown .sumanov;lc. ritsema & i3ril: system archilccllirc for 3d gravity modelling o -1 'iii "' g -2 ~ e 0 c 0 -3 ~ :5 ~ rn -4 ~p=~400 kglm3 -5 -1500 ~1000 ~500 0 500 1000 1500 distance from centre of dome (m) fig. ~ gravity anolllalies al the surface profile. in fig. 11, where the values also decrease with the increase of distance from the centre of domes. with respect to the previous examples it can be con­ cluded that it is impossible on the basis of anomaly shape to make any conclusions about source body. but gravity modelling can distinguish between cases because the existing mass differences result in clear anomaly dirferences both for surface profiles and for x­ sections, although the possibility of the prccisc separa­ tion of the domes decreases with the increasing distance from thc dome ccntrc. thcrefore in a practical sense, a salt dome can be defined more precisely if bore hole and gravity measurements afc situated closer to the domc ccntre. the best illustration of the previous statemel1l is the following example. if automatic gravity inversion is applied on the gravity field produced by an overhang­ ing dome, satisfactory results can not be obtained. the automatic gravity inversion procedure can not process complex structure, which has few z-values for the same surface ·200 ·400 i ~ ·600 \ :-li ·0 • " -800 ·joo!) ~"~ ·1200 0 2(1) 41)0 600 8110 10(1) 12110 1400 distance from centre of dome (m) fig. 10 gravity field for x-sect ion of overhanging salt dome. con­ lour interval 0.5 x 1o-5m/s'. density contrast ~p=-300 kg/m3. lsi surface -2flfl -400 i ~ ·61jo li m " ·800 ~o " .6' ·1000 ·1200 l....--:.--"--c 2 "00::--"c 400 :.,600 800 1000 distance from centre of dome (m) rig. <) gravity field for x-sect ion of cylindricdl salt dome. contour interval 0.5 x 1o-5m/s2 , density contrast ~p=-300 kg/mj . x and y coordinatcs. the result is unstable inversion, which mcans that a satisfactory model cannot be pro­ duced. the conclusion is that such a structure has a complex shape, which can be established by forward modelling. it is obvious, that gravity modelling can dis­ tinguish these cases. other complex structures, sllch as rcservoirs fissurcd by faults or other structural features will also benefit from these kinds of analysis . anothcr synthetic case can be described to illustrate the capabi lity of the inversion procedure. the inversion manager gives the structural form s of the horizon with constant density contrast bounding a single laycr from residual gravi ty anomalies using a regular grid . it must be noticed that the res id ual-regional separation should be carried ou t, mcaning that the regional gravity effect must be removcd from obscrvcd gravity anomalies by using appropriate methods. the gravity ficld at the sur­ facc produces the structure shown in fig. 12. satisfac­ tory interprctation of the gravity field can be attained in thc casc or morc comp lex geologica l models , as well. surface 0 .100 .4(1) i 'k ·600 m " -800 ·1000 ·1200 200 400 1200 1400 distance from centre of dome (m) fi g. 11 di fference in gravity fields of overhangi ng and cylindrical sal t domes. contour interval 0.1 x 1o-5m/s' . 152 geologia croatica 49(2 fig. 12 the slructure obtained from a given gravily field (gravity inversion). 5. conclusions two conclusions can be drawn. firstly, the applica­ tion of gravimetric data to constrain 3d simple and complex (structural and reservoir) models in the appra­ isal and development phases is possible and should be incorporated in daily practice. secondly, the described architecture, separating the model building and visuali­ zation subsystems from the algorithmic subsystems for forward and inverse simulation will support this in an open environment. the communication between two environments consists of a set o[ transformation rou ­ tines for various three-dimensional model representa­ tions. it will allow the easy intcgration of other simula­ tion software, such as magnetic, seismic and so 011. acknowledgement we thank prof. dr. zeljko zagorac for reading of the manuscript and useful comments. we also wish to thank prof. dr. c. reeves (itc international institute [or aerospace survey and earth sciences, delft, the netherlands), who acceptcd the manuscript for review, and dr. sally barritt (ltc, delft) for critical review of the manuscript and suggestions. 6, references bhattacharyya, b.k. (1978): computer mode­ ling in gravity and magnetic intcrprctation. geo­ physics. 43, 912-929. botezatu, r., visarion, m., scurtu, f. & cucu, g. (1971): approximation of the gravita­ tional attraction of gcological bodies. geophysical prospecting, 19,218-227. chenot, d. & debeglia, n. (1990): three-dimen­ sional gravity or magnetic constraincd depth inver­ sion with lateral and vertical variation of contrasl.­ geophysics, 55 , 327-335. cordell, l. & henderson, r.b. (1968): iterative three-dimensional solution of gravity anomaly data using a digital coillputer.geophysics, 33, 596-60l. gotze, il. -j. & lahmeyer, b. (1988): application of three-dimensional intcractive modejing in gravity and magnetics.geophysics, 53, 1096-1108. granser, h. (1987): three-dimensional inlerpreta­ tion of gravity data from scdimcntary basins using an exponential density-depth fullclion.geophysica! prospecting, 35 , 1030-1041. guspi (1992): three-dimensional fourier gravity inversion with arbitrary density contrast.gco­ physics, 57 , 131-135. slil1l;mov<ll:, ril ~elll:l. & i3ril: system architecture ror 3d gravity ivl odcll illg lines , l.r. , schultz, a.k. & treitel, s. (1988): coopcrative invers ion of geophysical data.­ gcophysics, 53, 8-20. mallet, j. l. ( 1989): discrete smooth intcrpolation. ­ acm-transactions on graphics, 8/2, 121 144 . mufti , i.r. (1973): rapid determination of cube 's gravity ficld.ge ophy sical prospecting, 21, 724735 . mufti , 1.r. (1975): it erative gravity mode lin g by us ing cubical blocks.geophysical prospecting, 23, 163-198. nagy , d. ( 1966): the grav itational attraction of a ri ght rectangular prism. geophysics , 31, 362-37 1. 153 oldenburgh, d.w. (1974): the invcrsion and intcrpretation of gravity anornali cs .geophysics, 39, 526-536. parker, r.l. (1973): thc rapid calculation of poten­ tial anomalies. geophy s. j. roy . a s t!". soc. , 41, 447-455 . plo uff, d. (1976): gravity and magnctic fi clds of polygonal prisms and application to magnetic ter­ rain corrections.geophysics , 41 ,727-74 1. talwanl , m. & ewing, m. (1960): rapid computa­ tion of gravitational attract ion of thrce-dimensional bodies of arbitrary shape. geophysics, 25, 203 -225. manuscript received january 11 , 1996. reviscd manuscript accepted september 11 , 1996. geologii1 croatic~ 49/2 i geol. c roat. 49/2 237 242 6 figs. 5 tabs. zagreb 1996 sciellfljh: paper production characteristics and reservoir quality at the ivanic oil field (croatia) predicted by machine learning system zvonilllir hernitz j • mi ro durekovic' and jos ip crnickj 3 proceedings kcjf words: iv3 1l ic oi l fie ld, reservoir qual ity, predic­ tion o r oil production, machine lea rnin g sys tem , expert systems. abstract ai [ile ivallie oi l ficld, hyd rocarbons are accumulated in fine to medium gl"ilincd li(hareni lcs or the [van ie-grad format ion (iva-sand­ sioi1c~ member) of upper miocene age. reservo ir rock s are divided inlo eight depositional (prod uc ti on) units (i livli l)' deposit s o f each linit arc c haracterized by th e ir own reservoir quaiil y parameters (porosity, horizontal permeability, net pay ... ). prod uction characteris­ tics of 30 wel ls have been studied by a simple slatistica[ method. two major production wel[ categorics ("good producers" and " bad produc­ ers") have been found . the contribut ion of each deposi tional unit to th e 10lal produc lion of iln individual well was sl udied by using :\ machine ic:ll"ll ing syslem which can serve as <i n expert system she ll. the results have shown ihal: [) the most important factors affecti ng the total hydrocarbon produc­ tion of each well arc horizontal penneability and net pay thickness of the depos itional units i v! i lv and i lll , 2) afler 20 wells had bee ll dri ll ed during the primary recovery peri od il was possi ble 10 predict the production category of a well to be drilled in the future with a rel iability of 80%. 1. introduction the ivanie oil fi e ld is s illlated in the north-wes lern part or the republic of croatia (fi g. i) . the fi e ld was d iscovered in 1962 on d rilling the iva-2 well. hyd roca rbons ha ve been accul1lulated in f ine 10 mediulll -grained iithare nites (tvanic-grad formation, iva-sa nd stones membe r) o f upper mi ocene age. th e trap is o f stfuclural orig in (an an tic lin e s triking from north -west to sou th -cast). t he s truc ture top de pth ranges from -1500 iii to -1 600 m. the first phase of reservoi r developmenl was com pleted in 1966. hyd ro­ carbon rese rves include oil, d issolved gas and a sma ll amollnt of gas in a gas cap. the fie ld mainly produces under a dissolved-gas dri ve. the primary recovery pe ri ­ od has bee n characte ri zed by a rapid dccrcase of reservoir pressure and by an increase of gor. in 1972, the sccondary recovery pe riod (waterfloodi ng) started . according to the genctic stratigraphic sequence con­ cept (gallow a y. 1989) rese rvo ir rocks have been di vided into eight depositional events (unit s) named it ivjjj (durekovic, 1995; fig. 2). the ivan ie oi l field produces from depositional units ilil-ivtl. stratigraphi c and depositi onal analysis, pe r­ formed by apply ing the total and net pay thickness, per­ meabili ty and porosity c riteria, have shown that reser­ voi r rocks are of bette r quality in the south-west part o f thc fi e ld. an elongated zone of bctte r reservoir qua lity, stri kes from the no rt h-west to sollth-east and co inc id es with the palaeod rai nage patt ern (durekovic. 1995). we ll production rate is re latcd to ihe rese rvoir qua li ­ ty. generall y, the total wcl l produc tion rate ca n be dc fin ed as a func tion o f individual depositional unit production. dcposits of each unit have been character­ ized by their own reservoir quality parameters (lola i and net pay th ickness, permeability , oi l satu ration ... ) . from a rcservo ir q uality poi nt o f v iew, the purpose o f our work is to define the impo rlance of each depositional unit and its contribution to the to tal well produc tion appl ying an expert sys tem. furtherm ore, wc int end to tes t the role of a machine learning sys tem in prcdic ting well produc tion charactc ristics. 2. methods and results ai the firs t s tage o f our work we have ana lyzcd thc average production behavior of 30 we ll s during the pri ­ mary and seco ndary recovery pe riod . a producfion illdex (pr ind) has been calcu lated for each wel l tak ing into accou nt well production rates and production peri­ od duration (time). a s im plc sta tis tica l mc thod showed the exis tence of two prod uc ti on we ll ca tcgories cf able i ). t he firs t catego ry ("bad produ cers") includes 13 wclls (out of 30) . p rod uct ion index values range from 1.5 to 5.5 during the pri mary recovery period and from 1.5 to 7.4 in the secondary phase of developmcn t. the i univer~i ! y of zagreb, facul ty of mining, geology & petroleum engineering, picrol!ijeva 6, r.o.box ) 86. hr-toooo zagreb, croatia . ~ l na-naftapl in , subiceva 29, ii r~ [0000 z:lgrcb, croatia. j fr:lll:\ gotovca 13. hr[(i()) 0 zagreb, croatia . 2}& seal e o !io l001<m _____ j fig. i locmion map. second category ("good producers") includes 17 well s. pr ind values vary fro m 4.8 to 12.2 in the prim ary recovery period and fro m 2. 1 to 10.8 in the secondary recovery phase. t he main differences between those two categories can be determined from average annual production rates (figs. 3 and 4; see also fig. 5 fo r well locati ons). four reservoir quality parameters (variabl es) have been analysed for each deposit ional (producti on) unit in each well: por effec tive porosity (%); hper horizontal permeability (x 1 0·' 11m' ); def net pay thickness (m); • so oil sa tu ration (0/0) . reservoi r qua li ty parameters (20 in to lal) have been named afte r ihe deposit ional unit number. for example, depos it ional un it iut has the fo ll ow ing variables: 3por, 3f-iper, 3def, 3s0 ; i,v has 4por , 4hper etc. the ana lysis also included three parameters com1110n for all depositional units in individual well s: • knv oil/water contact depth (m); • jk name of depositional uni t where oil/water cont act has been established; • sub ex istence of injection well (first neigh­ bour) (yes/no); all these va riables (23 in total ) have been analyzed by a machine learning system named "assistant profes­ siolla l" (cestnik et ai., 1987). it can automati call y const ruct decision trees from examples, and it can serve o '00 '" '50 '" ,m , w 1128 e sp '" 0",,100 iitll w ! i ' i! ~ i !j i geologia cro:ttic:t 49n deposi tional r e -iog unit (parase11>"11> marker 0..0" quence) <1l 11> rp <:i vlii ~o i) 0'" (;;'" i vli ",0 16 q;-'" i" c 15 0 ro iv "0 :tj i, ci ci .0: in 13 i ll l c 0 ro i, "0 :tj i ll ci 2 i, "i, ~ rs5 rig.2 depositional uni ts of genetic stratigr:tphic sequence iva. as an ex pert sys tem she ll for the acquired know ledge base (novinc, 1992; c rnfck i et a i. , 1994). the ass istant professional expert sys tem is a very fl exible computer package wh ich allows engineers 10 participate in the analys is by selecting the most important variables in decision iree nodes (crni( xf , 1989). during data analys is by the assis tanl profess iona l learning system, several ph ases were perform cd which approach the best possi ble prediction results. this paper di scusses four of them: i) phase i the learning system aulomat ically gener­ ates the rul es needed to classify the well in one of i \vo possible production categories. the system lised 23 variables [or each of" 30 wells. a decis io n diaprimary recovcry period secondary rccovcry period number of wells % catcgory (group) ii table i production index. (1962·1972) prind average prind t.5 5.5 3.2 4.8 12.2 8. 1 (1972·1995) (total 30) prind aver-age prind t.5 7.4 3.7 13 43.3 2. i . 10.8 5.5 17 56.7 l 30 100.0 hernitz. durekovic & cmicki: production characteristics and reservoir quality ntthe ivnnic oil field (croatia) predicted by ... 239 well no. 32 c 0 24 tl 0 ~ o ~ 0.. 0 16 c ~ 0 .. € " ro u 1 i ~ ' 1f~l~~ i l-m v ,\ 19 2 5 3 6 -18 22 8 e ~ ~ i ~ ~~~ 'r / r\::: , tv< l&l i '~ "it i -4 19 0 1960 1970 1980 fig. 3 hydrocarbon product ion rate "bad producers". gram (tab le 2) shows that depositional units iv, i,v and i lll affect the well production ratc much more than depositional units iv, and ivll' the most impor­ tant variables are horizontal permeability and net pay thickness (5i-iper, 4def, 3def). porosity (por), well structura l position (jk) and depth of oil/water contact are less important, as well as the existence of an injection well (fi rst neighbour) in thc vicinity of (he producer (sub). " 29.9 4def " 10.5 > 10.5 550 3def 5: 49 .s >49.5 " 19.7 > 19.7 jk i time 1990 2000 (year) 2) phase 2 a defined number of wells (5, 8, 11 and 14 from the total of 30) (table 3) are selected by ran­ dom number generation process to be used for a decis ion diagram rel iability tes t. the n, the expert system was applied to the rest of the wells (non­ selected) taking into account acquired knowledge from phase 1 (including a decision diagram and the importance of variables [rom the tree). finally, a new decision tree was generated and tested on a cho5hper > 29.9 3def " 19.7 > 19.7 7def 5: 2.5 > 2.5 6por ::;; 4.5 >4.5 " 20.6 > 20.6 category 1 2 2 1 table 2 decis ion diagram (phase i). 32 i i i i i i o 1960 1970 1980 2 2 i 1990 2000 " 21.7 1 well no. 11 13 7 12 24 27 28 29 -15 30 time (year) 2 4por > 21.7 1 2 fig.4 hydrocarbon produc­ tion rate "good produ­ cers". 240 injector-well section p roduction group boundary oil/woter contact c ontrolwetl • producers-group i • producers-group ii °ci =======5;oo~ ....... 'ooolm) number of wells number of corteet reliability learn ing testing answers (%) 25 5 5 100.0 22 8 7 85.5 19 11 8 72.7 16 14 10 7 1.4 table 3 reliability of well category prediction (phase 2). case (a) (without human intervention) nulllber of well s number of reliability lear-iling testing correct answers (%) 25 5 3 60.0 22 8 4 50.0 19 ii 5 45.0 16 14 6 43.0 • • • geologia croat ic:t 49/2 fig. 5 production well category and locati on map. sen les t we ll s. the proced ure was repeated three times. average results arc shown in table 3. the gene ral conclusion is: pred ic tion reli abi lit y is proporti onal to the num ber of learning well s. in a ll cases rel iability is greater than 70%. 3) phase 3 the ex pert system fo llowed the same proce­ dure as in phase 2, wi thou t laking into account knowledge from phase 1 or phase 2. table 4 shows the re liability for two different cases. tn case (aj case (b) (human intervention, fixed variables 5hper, 4def, 3def) number' of rcli~)bility correct answers (%) 3 60.0 5 62.5 6 55.0 7 50.0 table 4 rcliabilil y of well calcgory pre­ diclion (phase 3). ifernie/, dureknvic & crnick i: production characteristics and reservoir quality at the ivanie oil field (croalia) predicted by ... 241 . 25 control well \~ ~ contour line (m) production group boundary 5 wells tested oftel ... d d v o step 1 -learning on 10 wells step 2-leorning on 15 wells step 3· learning on 20 wells step 4-leorning on 25 wells • • • _ true _ false stage of experiment • • i ii initial·learning on 10 wells 'bad producers' "good producers' • ( _______ · 1540 _____ ,156<) _-"'--~ _____ ·,580 ____ ~ o = l=~ .~ ci ====~ ____ ' '-~ fig. 6 succession of there was no human intervention in decis ion ana l y~ sis. in case (b) the first two levels (nodes), the most important variables were selected by us (human inte rvention ). results show tha t human experi e nce can help the expert system to obtain beller result s. 4) phase 4 shows how the machine ieaming system can be used during reservoir exploration or/and deve lop­ ment. at the beginning we selected 10 wel! s o ut of 30 according to thc drilling succession (welli was drilled firs t, well-2 was drilled afler we ll'--.). the sys te m generat es the deci s ion tree a utom at ic ally from the da ta base for those 10 wells. re liability o f" the decision tree ana lysis was tes ted on fiv e wel ls numbcr of wells number of corrcct reliability ic31"1ling testing answers (%) 10 5 2 40.0 15 5 3 60.0 20 5 4 80.0 25 5 4 80.0 table 5 reliability of well category prediction (p hase 4). rese rvo ir explorati on orland development. (planned to be drilled) assliming that we would be able to predict thc va lues or variab les needed for pre­ diction from the already known geolog ical situation. the procedure was repeated until 25 learning wells were reached. results show (table 5; see also well locations in fig. 6) that 15-20 wells shou ld be drilled before the expert system can predict the production category of future (planned) we ll with a reliability of 80%. 3, conclusions 1) a machine learning syste m can be used in orde r to predict the s igni ficancc and contribution of individ­ ual production units, to the lotal well produc tion tak­ ing ij1lo account their reservoir quality (phase 1). 2) human intervention based on experience in many eases will help the expert system to obtain bel1er and more reliable results (phases 2 and 3). 3) a machine learning system is 01" grea t he lp in plan­ ning reservoir exploration and/or dc ve lopment process by predicting well produc tion behaviour on the basis of the known geolog ical c harac te ri s tics of 242 reservoir rocks (phase 4). this gives us an opportu­ nity to predict the minimum number of wells needed to achieve a maximulll production effect. 4) further improvement could be achieved by a si milar analysis in 3d space. s) in the geological dec is ion maki ng process the machi ne learning systems are able to red uce the number of bad producer wells. it cou ld be recom ­ mended to usc the described or similar methods as it has importance in the oi l-production economy. 4. references cestn ik , b., kononenko, i. & bratko, i. (1987): assistant 86 a knowledge elicitation tool for sophi sticated uscrs.in: bratko, i. & la v­ rac, n. (cds.): progress in machine learning. sig­ ma press, 3 1-45, wilmslow. crn icki , j. (1989): kno wledge based systems in geology.proceedings of international conference geologia croalica 49/2 on mathematical methods in geology, 2, 652-658, pribram. crnicki, j., hernitz, z. & cestnik, b. (1994): oil forecasting in slavonia (croatia) by the assis­ tant professional ex pe rt system shcjl.croatian geotechn ical journal , 1/1-2,13-17, varazdin. durekovic, m. (1995): sedimentation and reservoi r c harac teri s tics of iva sand stone at the oi l fi e ld of ivanic.unpublished m.sc. thesis, univers ily of zagreb, 58 p., zagreb. galloway , w.e. (1989): genetic stratigraphic sequence in bas in analys is i: architecture and gen­ esis of floo ding-surface bounded depositional uoits.aapg bulletin, 73/2, 125142. novinc, m. (1992): possibilities fo r est imation of oil and gas in the eastern part of drava bas in by a machine learning system.unpublished m.sc. the­ sis, university of zagreb, 85 p., zagreb. geol. croat. 50/2 279 288 10 figs. zagreb 1997 hydrogeological exploration of the rjecina river spring in the dinaric karst bozidar biondic, franjo dukaric, mladen kuhta and ranko biondic key words: hydrogeological exploration, dinaric karst, karst spring, karst aquifer, overthrustecl stru­ ctures, deep retention spaces, new intake structure, access gallery, monitoring of the karst aquifer. abstract the rjccina sp ring is one of the major springs in the dinaric k arsl it appears al the contact between permeable carbonate and impermeable clastic rocks, with a discharge of up to 120 m3/s but it dries up during the dry summer seasons. the spring occurs close to the town of rijeka, 325 m above sea level and offers an outstandi ng op portunity to cover grav ilalionally the public water demand of a town of about 200,000 inhabitants, and the touristic needs of the who­ le region. this hydrogeological research project is a pan of efforts to solve lhc problems of water deficiency during the dry summer sea­ sons up to a maximum of three month s. it was necessary to enter the parts of a karst aquifer that are active eve n in time of any outflow from lile rj ecina spring by complex geological, hydrogeological and geophysical exploration accompanied with deep exp loratory bore­ holes. during earlier explorat ion, it was detemlined lhat there are no active innows in the immediate hinterland of the spring and that it is necessary to discover the inflows from olher karst structures, that behave as retentions of karst spring s in the zolles of permanent dis­ charge. the presence of tllultiple overthrusted structures in the zone around lile spring site suggest the ex.istence of deep zones of water retention, which may be reached by an access gallery from the rjecina canyon. this work represents a substantial change in the exploration methodology for dinaric karst aquifers, because it directs the researchers toward deep, unknown retent ion spaces which contain large reserves of high-quality groundwater outside urban areas. 1. introduction the rjecina spring is the largest karst spring in the northern adriatic area, but it is inactive during the sum­ mer dry seasons for lip to three months a year. this is a great problem for the water supply to the town of rije­ ka (fig. i), because all groundwater extraction sites in the coastal area have to be activated during these peri­ ods. thi s is a risk to high water quality and a conside­ rable cost as the water has to reach 540 m above sea level. the rjecina spring, occurring at 325 m above sea institute of geology, sachsova 2, p.o. box 268, hrioooo zagreb, croatia. level would be an economically and technically vcry favourable gravitational water supply for the largest part of the town. moreover, the rjecina spring water is of extremely high quality with the potential of remaining so for future generations, as the spring catchment area in the mountains of gorski kotar is protected 10 a water reserve level the rjecina spring occurs a substanti al distance north of the closest urban center of the rijeka area (fig. 2). it has only recently been of interest as part of the urban water supply as previous demand was covered by supply from coastal springs. this was also influenced by the temporary dryncss of the spring during summer dry seasons, when the dcmand for potable water reaches a maximum. the hydro-power potential of the spring initiated the first studies after world war ii. poljak and crnolatac directed their exploration toward estimation of the possibilities of water storage in the predominant flysch deposits of the rjecina river valley without much consideration of the karst catchment areas. sikic & plenicar (i975), the authors of the basic geological map 1: 100,000 sheet ilirska bistriea, provided a base for the exploration of the karst areas, as this map com­ prises the carbonate massif of a part of gorski kotar and slovenski sneznik mt. which drain towards the rjecina spring and other karst springs within the rijcka region. the first hydrogeological bases of the carbonate hin­ terland of the rjecina spring were made by biondic and vulic in 1969. for the first time the rjecina spring ca­ tchment area was defined and comb ined with a very detailed hydrogeological description. this was, also, the first hydrogeological definition of a karst catchment area in the dinarides. within this exploration, bozicevic performed a speleological exploration, including deta­ iled research of the rupa ponor in the grobnicko poije. the rjecina spring was also of interest to researchers of karst morphology and it was first exp lo red by italian diver-speleologists in 1928. they reached a depth of is m, followed by croatian diver-speleologists in 1971 (to 34 m), 36 m in 1984 and 50 min 1996. during the most this paper was presented at the scientific meeting dedicated to the 80th anniversary of the life of professor milan herak, held on march 5th, 1997 in zagreb pannonian basin 50 too km "\ ~ijek<_" vu/(o'o'.,l,,_, -'-"'\ ( <) fig. i the dinaric karst region in croat ia showing the posi tion uf tile' study area. recent study in 1996 a lower channel was discovered at depth (kuhta, 1998). groundwater was twice pum­ ped ou t from the spring cave system during the dry summer seasons of 1969 and 1973 . vast cave spaces were opened and speleologically cxp lored by bozi­ cev ic (1973, 1974). under natural condi tions, these cave spaces had been fi lled with remnant water even in the summer dry periods. in the upper part of the cave system, a 20-m-long gallery was constructed to facili­ tate entry to the cave even during high water stages. si nce 1971 , the rjccina spri ng has formed an incre­ asing part of the hydrogeological research projects of the entire catchment area of springs discharging in the town of rijcka. during these explorations, numerous detailed mappings and groundwater tracings were made in the carbonate hinterland of these springs, which hel­ pcd to define the catchment area. to maximise the use of the rjecina spring, a cons iderable possibility would be to build a surface dam submerging the spring. rece­ nt study showed tha t the immediate area around the spri ng does not conta in significant amounts of water, but the spring can be submerged without problems, i.e. wi thout water losses toward the downstream parts of the catchment area. the basic conclusion was that the close spring hinterland occurs intermittently out of the influence of deep underground retentions which control the spring discharge during the summer dry seasons . therefore, new explorations should be directed toward those geologic structures which are potentially ac ti ve aquifers during the summer dry seasons. 2. geological review generally, the base for the hydrogeological explo­ ration of karst areas is a good knowledge of the geolo­ gical structure, but it is of a special importance for the rjecina river spring wherc all the complexity of the o 10 km legend: ,. 3 ." 5 • 4 6 fig. 2 a tectonic sketc h of the sllldy area. legend: i) bollndary between the adriatic and dinaric units; 2) main reverse fault: 3) faults; 4) geological boundary; 5) watershed; 6) rivers; 7) rjecina spring. structural composi tion of the dinarides is fully displa­ yed (herak, 1986, 1991). the lithostratig raphy and tectonics define the geometry of karst aquifers into which the hydro-dynamics elements can be included. within the rjecina spring area, the aquifer is com­ posed of cretaceous and palaeogene carbonate rocks, while the palaeogene flysch deposits form a barrier to groundwater flow. in this study, the most important influence were certain lithostratigraphic changes within thc carbonate mass, and the structural position of vari­ ous lithostratigraphic units (biondlc, 1988). the lower cretaceo us limestones and calcareous breccias (k ,), the oldest rocks in this area, form an anti­ cl ine which can be traced from the rjecina river hinter­ land, to the north-western edgc of the grobnicko polje. the calcareous breccias are overl ain by dolomitized breccias (k 1.2), up to 150 m thick, formed by late-di a­ genetic dolomitization of tectonised transitional depo­ sits between the lowe r and upper cretaceous. the dolomitizcd breccias are overlain by an upper creta­ ceous (k~·2) unit, 500 m thick, in which dolomites and limestones alternate. dolomites prevail in the hinterland of the rjecina spring, and gradually pass into a pure upper cretaceous calcareous complex of rud ist lime­ stones (k~·3), up to 350 m thick. at the transition to palaeogene deposits , the sedimentary environment sub­ stantiall y changed . continental sedim entation began over a marked karst relief, wi th occasional lagoonal and brackish lake sed iments as for example in the hinter­ land of the spring, where the palaeogene began with liburnian deposits. following a marine transgression over the area typical marine foram in ifera l limestones biondic, dubric, kulua & biondic: i-iydrogeological exploration of the rjetina river spring ... 2" (ei.2)' up to 200 m thick, were deposi ted. toward the river za la va lley, a gradual transition toward clastic sedim entation above the foraminiferal limestones can be observed. this began with 30-50 m thick trans it ional clast ic deposits ('ez.3) and continued with n ysch depo­ sit s ee, ~ ), the thickness of which might reach about 600 m (based on their thickness in the {sl rian dysch bas in). the eocene-oligocene calcareoll s breccias (lclar depos its) have not been observed within the exp­ lored arca. t hc quaternary sediments are very impor­ tant for thc understanding of events when th e actual surface and underground hydrosystem was fonned. the occurrence of pliocene-pleistocene lacustrine sediments a t the norlh-weslern edge of ihe grobnicko polje indi ­ cate the ex istence of a palaeodepression before the quate rnary. these lacustrine sedi ments (grave l and cong lomerates), and nuvioglacial fan s toward the sur­ rounding mo untainou s area are the results o f heavy glacia l act ivi ty in the catchment area. the remnants o f ri ver te rraces (sandy-clayey sediment s with cobbles) a lso have a significant role as they show the arrange­ ment of surface stream s in their gene tic sequence dur­ in g the quaternary. deluvia l and outwash depos its on steep slopes of the rjecina river canyon reflec i recent erosional processes and do not affect the hydrogeologi­ cal interpretations. intc rpreting the geological structu re, it is necessary to cons ider not only the local condi tions but a lso the reg io nal ones, as the hydrodynamics is related most c losely to the regional tectonics. for the study area, as well as for the whole of the dinarides, it is importan t to de fin e the re lationship of thc macrostructural units. according to herak (1986, 199 1), in the rijeka regi­ on this means the relationship between the dinaric and adriati c units. thei r mutual relat ionship is significant for the formation of groundwater and its now toward the adriatic coasta l area. according to our exploration, the boundary between these two macrostructural uni ts stre tches a long the thrust contact of the obruc structural unit. thi s is a continuation of a fault contact extending from il irska bistrica, in s lovenia, over the ravno area, to the north-western edge of the grobnicko polje. the grobni cko polje was formed at the intersection of num erous large perpendicular faults. they caused the south-westward transposi ti on of dinaric structure and the covering o f adriatic structurcs to the vinodol nysch va lley (fig. 2). according to this interpretation, the car­ bonate mass if of the rjeci na spring hinterland belongs to the adriatic megastruc tural unit , which is charac­ terised by fo lded struc tures and numerous imbricatc­ thrust struc tures and , at the carbonate massif border, large occurrences o f palaeogene n ysch deposits. this is also con firm ed by normal lithostratigraphic transitions from areas of carbonate sedimentation to clast ic ones in the arca of za le and ravno to the north of the study arca. the loca l tec tonic structures of the rjec ina spring area bes t re fl ec t the regional relationships. on the cliff above the spring, many thrusts occur within the carbonate complex, and also throughout the carbonate massif over the fl ysch deposits, as well as inte nse ro tati ve faultin g whi ch caused mutual movemelll s of part s of the overthrusts and the formation of struc tural blocks. the highes t thrusted structure is p laced cast of the spring, on a plateau above the canyon. th is structure has a very important function in further hydrogeologi­ cal deliberations within this project. in this " top" thrust­ ed struc ture, the carbonate rocks are fold ed and of a very variable composition: f rom very permeable lime­ stones to poorly permeable dolomites. from a hydroge­ ological aspect, a crushcd anti c line of dinaric strike having very penneable lower cretaceous limestones in its core is of special in terest. t hi s antic line lies parallel to the rjecina river valley (canyon). in the grobnicko polje area, th is anticli ne is entire ly opened on one side forming the main seasonal groundwater discharge zone during the rainy seasons . from the grobn icko po lje toward the rjecina spring h inte rl and, the ant icline pl unges s light ly, and the very permeable limestones have progressively th icker cover or low pe rmeab ility dolomites and dolom itic breccias . to the east of thi s anticline, a synclinal form opcn s, and it s margin is obscured by the dinaric obruc overthru st. the wholc structure of the rjecina spri ng hinterland sinks toward the north-west, hence, progressively you nger deposits are recorded in this direction, toward ravno and mjaka, where there is a gradual transition of carbonate rocks into impermeable flysch that forms northwestern boun­ dary of the struc ture. geomorphological phenomena, as in all karst areas of the dinarides, arc a direct result of the litholog ical characteris tics, geological struc tu re , hydrogeological propel1ies of rocks and the changes in hydrological and meteorological cond itions, particularly during the qua­ te rnary epoch. the relief form in g processess must be considered dynamically, through time, because the pre­ sent state is only a momentary reflex of the interact ion of endogenous and exogenous processes. thc material traces in the shape of morpholog ica l phe nom ena and younger sediments (river valleys, river terraces, under­ ground phenomena etc.) enable at leas t a parti al recon­ struction of the geomorphological deve lopment of a ter­ rain and, importantly provide insigh t into the genesis of the ac tual hydrogeological relat ionships and groundwa­ ter dynamics. sed imentary outcrops indicate that the grobni cko polje depress ion was a lready form ed by the pliocene, when numerous karst poljes in the dinarides were lakes. the grobnicko polje is possibly the starting po int of the development of karst processes for the whole catchment of all springs in the rijeka reg ion (bion­ die et ai. , 1998). present re lief fomlation is associated with the pleistocene and the alternation of glac ia l and intcrglacial stages . intense g lacial ac ti vity is obvious from the discovery of glacial scd im ents in the moun­ tainous area of platak and snjeznik. t he inte rg lac ial stages brought increased amounts of water resulting in increased erosion and fluviog lacial sedimentation. in the area of grobnicko polje and higher located goman­ ca polj e, glacial lakes were formed. these had a con­ trolling function in the development of underground karst morphology and kars t aquifers during the quater­ nary. a study of quaternary sediments shows thai all sur­ face streams were directed toward the grobnicko polje. the bed of the intermittent stream zala still down cuts from the ravno area to the grobnicko polje. the case of the rjecina spring and the development of the lenght of this river canyon is especially interestin g. the river spring and canyon are geologically very young features. the discovery of terrace sediments on a carbonate ridge in the spring hinterland (about 220 m above the present spring site) are indicators of surface streams in the hin­ terland prior to the existence of the large karst spring at the hi gh rock foot. the terrace sediments also confirm that all surface streams, including the rj ecina river, rjowed toward the grobnicko polje. through the development of karst processes, water from the surface progressively was descending into the carbonate underground and the deep canyon was being deepened in the area composed of fl ysch rocks. the di scoveries of fossil springs hi gh in the clifr above the present spring confirm the gradual canyon opening and the water removal into a deeper karst underground. this erosional process is ongoing, as confirmed by discovery of two cave conduit s at the rj ec ina spring (802:1cevic, 1974). one of these is overflowing and the oth­ er ascending, wh ich wi ii result during future canyon development , further deepen ing and water springing at another, somewhat lower level. the rjecina strea m, during its first deve lopment ph ase, flowed into the gro bnicko polje. the runoff from the grobnicko polje 10 the present bay of kvar­ ncr, which was not submerged in thai time (s egota, 1968), was effected only through the karst under­ ground. the main water communication was directed toward the zvir spring in rijeka. the erosional bed of thi s spring is much deeper than the bed of the rjecina river. this is now the main drainage direction of a large kars t catchment area of springs in the lown of rijcka. the deep rjecina ri ver canyon dominates the mor­ phology of the study area. it has been mostly fo rmed in oysch sediments, whi le massive carbonates oecure abo­ ve and surrounding the hinterland of the spring. the plateau is characterised by elongated valleys and struc­ tures directed toward the grobnicko polje. an expres­ sive morphological step is formed by the obruc over­ thrust, that is also a boundary of the adriatic and dina­ ric macrostructural units. numerous speleological phenomena have been rec­ orded in the study area. the largest phenomen arc the cave system of the rjecina river spring, extending hori­ zont ally over more than 200 111, and the rupa ponor in the grobnicko poljc, which is part of the main zone of ponors toward the coastal springs. ......... v .vb'" ... 'v." ..... " ."" o. 3. hydrogeological review the general hydrogeological situation of the who le catchment area depends 011 the tectonics and the signifi­ cant lithological variation of this area. the lithological characteristics directly affect the hydrogeological prop­ erties of these rocks, whi le their vertical and lateral changes inouence the spati al arrangement of potenti al aquifers. within the carbonate complex, in the area o f the rjecina spring, two groups of rocks of different hydro­ geological characteristics may be distinguished. while the limestones represent a very permeable med ium and generally the main grou ndwate r col lectors, the dolo­ mites arc much less permeable and very often form bar­ riers to groundwater flow, within very permeable lime­ stones or they direct thi s nows a long the bounding structures. the flysch sediments are generally impenne­ abl e and they, depending on their structural pos iti on, also form barriers to gro undwater flow in karst areas. the rjecina spring appears at the tectonic contact between very permeab le karstified limestones and the eocene flysch. however, groundwater flow is recorded be low impermeable fl ysch sediments at some other sites. the quaternary deposit s, depe ndin g on the ir lithological characteristics, are of variable penneability; however, they have no major significancc in thi s area due to their relatively small thickness. it would be too simple to assume that very penne­ able limestones are always a lso acti ve aquife rs. t his depends both on the position of the rock units and the geological structure of the terrai n, and those exp lains the complex ity involved in the hydrogeological ex pl o­ ration of karst terrains, especially in the high zones of karst catchmcnt areas. considerable changes in the con­ ditions of groundwater dynamics of the study area have to be connected with the lates t vertica l and rotary movemen ts of the tectoni c forms that were originall y tangentional (overthrusted geologie st ructu res). all larger spring sites in this catchment area are associated with the latest tectonic movemen ts. this refers to the rjecina spring, to the intermillent springs at the north­ western edge of the grobnicko polje and to the penna­ nent coastal group of springs as zv ir and martinsc ica. even the fl ysch zone, stretching almost continuous ly from the bay or trieste to the town of novi vinodolski , does not function as a hydrogeological barrier along its full length. thi s is caused by its variable depth due to the latest tectonism and eros ional processes. the rcsult is that groundwater flow s through the upper cretaceous and eocene hi ghly permeable karstified lim esto nes beneath the fl ysch. a s imilar case is the underground fl ow from the ponors in the grobnicko polj e to the coastal springs zvir and martinscica. the rjecina spring is an int ermittent karst spring reaching a maximum di scharge rate of 120 m3/s (annual average about 8 m3/s). it is a part of the intermittent dis­ charge zone from the catchment area of the rijeka town springs (biondlc, 1988; biondic et ai., 1995) thai biondic. dukaric. kuhta & biondic: hydrogeological bploration of the rjecina river spring .. 283 n a = 0 10 km legend: d ., 8 0 15 • 22 d 2 n 9 • 16 z: 23 lj 3 n 10 ~ 17 id1 4 n 11 0 18 d 5 '" 12 19 d 6 n 13 0 20 d 7 0 14 :.: 21 fig. 3 the regio nal hydrogeological map. legend: j) quaternary lay­ ers of variable permeability, relativel y small thickness; 2) qua­ ternary layers of low permeability, relatively small thickness; 3) hi ghly permeable alluvial deposits; 4) high ly permeable carbon­ ate rocks; 5) medium permeable carbonate rocks; 6) low perme­ able carbonate rocks; 7) impermeable clas tic rocks; 8) ma in reverse fault; 9) fault; 10) geological boundary; 11 ) groundwater now directio n tes ted by tracing; 12) watershed; 13) river; 14) in take structure; 15) dug well; 16) drilled well ; 17) hole with water; 18) ponor; 19) cave; 20) hole; 2 1) estavelle ; 22) spring; 23) submarine spring. compri ses a wide mountainous area in gorski kotar and a part of the slovenski sneinik mt. the penmanent springs of this catchment area are: zvir, extraction site zvir ii , pumping site martinscica and coastal springs in the town of rijeka. this is the most productive catch­ ment area in the northern adriatic region and the main potable water supply for the town of rijeka, and a major part of the bay of rijeka (approximately 3 m3/s during the dry summer seasons) . the rjecina spring occurs high in the catchment area (325.2 1 m above sea n a' ~ 11m m legend: c:::::::::j 8 15 lj 2 9 r--16 c:::::::::j 3 10 = 17 .. 4 11 • 18 c:::::::::j 5 e 12 b b' 19 c:::::::::j 6 e 13 c:::::::::j 7 e 14 fig. 4 a detail hydrogeological map of the study area. legend: i) highl y penneable debris; 2) low permeable debris; 3) highly per­ meable alluvial deposits; 4) highly penneable carbonate rocks; 5) medium penneable carbonate rocks; 6) low permeable carbonate rocks; 7) imperm eable clastic rocks; 8) main reverse fault; 9) reverse fault ; 10) fault; 11) geological boundary; 12) rjecina spring; 13) est ave li e; 14) small sp ring; 15) groundwate r flow direction tested by tracing; 16) river; 17) proposed gallery; 18) exploration borehole; 19) cross section 8-8 ' . level) and has the function of an overflow for medium and high groundwater, for which the nat ural under­ ground flow is directed toward the grobnicko polje and the permanent coastal springs (fig. 3). the springs at the north-western edge of the grobnicko polje are also intermiltent , but they are active for a much shorter peri ­ od than the rjecina spring, hence, watcr only flows out from those springs during the high stages. during dry seasons, the grobnicko polje springs are without water, but the water flows through the deep karst underground towards the permanent coastal springs. this flow is monitored in several observation boreholes and has becn confirmed by numerous water traci ng tests (bio­ ndle et ai., 1979). the immediate hinterland of the 2<, geologia cro:l\ica 50/2 _69 " 700 a.s.!. s' na sten i .00 s k , ", k ' .' 0--200m u s d k 2 1,2 5 10 11 12 o t 2 o k" , 6 d e", 3 b k, 7 _ e" 1 8 blk 2 2 ,3 4 ~ 9 13 fig. 5 cros~hcctjoll through the nclive karst aquifer with the proposed intake gallery. legend: i) intergranular porosity. high permeability; 2) intcrgranular porosity, high to variable permeability; 3) impcnncable clastic rocks: 4) high permeable carbonate rocks; 5) med ium perme­ able carbonate rocks; 6) low permeable carbonate rocks; 7) high permeable carbonate rocks; 8) geological boundary; 9) erosional boundary; 10) fault; 11) presumed fault; 12) proposed gallery; [3) borehole sp-3. rjccina spring also lacks an active groundwater circula­ tion, although its cavernous conduits are filled with delayed groundwater. the described water dynamics in the catchment area of the rijeka town springs has been defined by numer­ ous groundwater tracing tests. for the high parts of this area, 10 which the rjecina spring belongs, the tracing of a sma ll ponor al trslenik village in the mountainous pari of the catchment area is particul arly interesting. it was performed at ihe beginning of a summer dry sea­ son, when the flow from the rjecina spring began to decline and the intermittent spri ngs on the north-west­ ern edge of the grobnicko polje were dry, while about 1.5 m)/s flowed out from the permanent coastal spring zvir. the observation boreholes at the north -western edge of the grobnicko polje and the permanent coastal springs of ihis catchment area werc monitored. the appearance of ihe tracer in the boreholes and permanent springs confirmed groundwater connection between the mountainous area of high precipitation (more than 3,000 mm per year) and thc zones of intermiltent and permanent springing. similar results were also pro­ duced by the tracing of ponors in mlaka situated adja­ cent to the intenniuent springing zonc. for thc rjecina spring, what happens in the zone of intermitlent spri ngs is the most important. this zone belongs structurally to the adriat ic edge. it is a folded area of dinaric strike, where each fold thrusts over the other, as is clearly visible on the cliff abovc the rjecina spring. in these folds, limestones and dolomites alter­ nate. a combination of the folded masses of different hydrogeological characteristics, combined with a north­ westwards sinking of the whole structure under the impermeable flysch deposits, forms a basis for the for­ mation and flow of surfacc and groundwater. the whole carbonate mass, at its north-western side, is bor­ dered with impermeable flysch (fig, 4) and, at its south-eastern side in the grobnicko polje, cut by a strong perpendicular fault. along this fault, the main drainage direction is formed toward the permanent springs of the catchment area (b10ndlc ct ai., 1995), the challenge for hydrogcological exp loration was to determine whether it would be possible to extract deep groundwater during the dry summer seasons, when the rjecina spring is inactive. such action has not previously occurred in the dinaric karst terrains. alter­ natively, onc intermittent spring must bc transformed into a permanent one in order to provide a permanent urban water supply from a high, unurbanised zone with­ in the same catchment area. taking into account the absence of active groundwater inflows in the immediate vicinity of the spring during the dry summer seasons, the exploration had to be directed to other structural forms which, even during dry seasons, keep an active connection with the main recharge areas in lhe moun­ tainous part of the catchment area. the tangentional structural forms offered such a possible solution. detailed hydrogeological mapping of the spring area highlighted a manifold overthrusting of carbonate rocks of different hydrogeological characteristics (lime­ stones and dolomites) at the eastern side of canyon, and the very spring zone. this suggested the possibility of the existence of active aquifers even when thc rjecina spring is inactive. the hydrogeological map (fig. 4) and the cross-section (fig. 5) show three such over­ thrusts with paraclases inclined mainly north-eastwards. the first overthrust is composed of very permeable limestones lying over the flysch barrier and directly passes the spring site. the second overthrust is visible high on the slope, above the spring, and this overthrust above inspired the search for an active aquifer. it is part of a folded structure that extends south-eastwards to the grobnicko polje where is the huge intermittent dis­ charge zone, reaching the rate of up to 15 m3/s in rainy biondic. duk~lric. kuh!;l & i3iondic: i iydrogeological explora!ion of !he rjclina river spring ... 285 seasons . t he core of the folded struc tu re is composed o f lower cre taceous highly permeable calcareous brec­ cias and limestones. these rocks, being covered by younger poorl y pcnncable dolomitized breccias, could be a good medium [or the formation of "capt ive" aqu ­ ifers. the th ird overthru st which covers the aforemen­ tioned thrust fold and its very permeable limestone zo­ ne is too high to be in the zone of ac ti ve g roundwater c irculation. detail ed hydrogeolog ical mapping was followed by geophysical exploration using double grad ient mapping ancl res istivity sounding. the sounding reached depths sufficient to enabl e hyd rogeological interpretation to below the rjecina spri ng level. by interpreting the mea­ sured geoelcclrical data , three sites o f well -marked minimums (maximal d ifferences in the rock res isti vity for two deep ho ld) were d iscovered along the core o f the fold structu re . the rcsults of the hydrogeological mapping and geophysical exploration were used to pre­ pare the forecast c ross-sectio n whi ch were a bas is for de finin g of the locations and dep ths of exploratory boreholes. the exploratory-observation boreholes were located along the co re of the fo ld structurc that fo ll ows the rj ec in a river valley to the northwes tern edge o r the grobni cko polje. one of the boreholes (si'-3) provided da ta a ll ow in g fu ll description of the hyd rogeo logi cal cha racte ri stics of the acti vc karst aquifer (figs. 4 & 6). down to a depth of 145 m below su rface, thi s borehol e was d rilled through practical ly impermeabl e lower cre taceous dolomitic breccias, with a constant return o f drilling water. however, whe n the borehole reached hi ghl y penncab le crushed calcareous breccias a t the depth of 145 111 , an abrupt loss of drilling water oceured combi ned wi th a s imultaneous su bartis ian ri se o r groundwater level high above the contact betwecn the impermeable and pemleable rocks. the borehole ended at a depth o f 300 m in the highly permeable lower cre­ taceous calcareous complcx. it may be concluded that th e hi gh ly permeabl e lowe r cretaceo us ca lcareous brecc ias and limeslones form an active karst scm icon­ fin ed aqui fer, even during the summer dry seasons. signifi cant results were obtaincd from the monitor­ ing of grou ndwater levels in the region surrounding the rjec ina spring, and at th e north-wes tern edge of the grobni cko polje, and have been compared with the ra tes of discharge from the rjccina spring (fig. 7). data from the observa ti on boreholes an ound the rjecina spring and those at the north-western edge of the grob­ nicko polje suppo rt the theory o f full aquifer ac tivit y even during a tota l cessat ion of acti vity from the rjecina spri ng. to defin e the aqu ifcr dynamics, good results were obtained by measudng groundwater tcmperature along the aqu ifer depth in dilterent hydraulic conditions (fig. s) . th e boreho le sp-3 showcd a constant decrease of water temperature downwards approaching the temper­ ature of the rjecina spring water (7.5 °c) and thi s a lso mean s the approach to the depth from where wa ter lithology f--.-+-,---+=~ '" " • '" -'\149 iii 196 m 51'-3 description low permeable dolomitized breccias low permeable dolomitized limestone high permeable calcareous breccia high permeable limestone 1.,----='. -"'=-1 -.nqm fig. 6 exploratory borehole sp-3. f lows toward the spring. thi s is also an indi cator of an active aquifer, open toward deep structures, that is also possible geologically. a different situati on ex ists in the observation well at the north-western edge or the grob­ ni cko polje where the lower temperatu re values were ljeo!ogla lroallca )u/l _----'-___ '-_j ____ -'-~. ~ 100 _ rjt'<"inj q s r-2 t 10 0 si'-3 -si'-4 ~ e" " ~ :;; , 0 ci si' -s sp·6 so rjstinjfk" luh( rjctina ic\'ei o i, 1 ~1j,f1994 06,'0111995 2810511995 19!iqli995 d<lle i 1110311996 rccordcd in thc shal low pans of aquifer (fig. 9), which is the normal situation in spring zones. the electrical conductivity measurement under various hydraulic con­ ditions showed a constant exchange of water in the deep karst underground (fig. 10). groundwate r flow tracings from the obse rvation borehole sp-3 determined the connection of the i groundwater temperature (.q i 8.0 8.2 8.4 8.6 8.8 9.0 9.2 9.4 9.6 9.8 10.0 424 j) i 404 ~, i .,.' 384 ii 364 ..r. •• ' ~ ;"1"" ~ " • g 344 , " c '0 ~ c 0 324 / . . ~ ~ jl i ~ j ~ 0 304 • i -b ~ / 0 --spring c 284 i 0 --summer .~ i > • -autumn w i 264 i ..... . winter i 244 i i i 224 i fi g. os diagram of the g roundwater temperature variations ill lhe borehole sp-3. 02!08t199& 2411 2119% fig. 7 diagram of th e observed grollndwater level s and rje­ tina spring capacity. explored karst aquifer with groundwater at the nw edge of the grobnicko polje, and also with the rjccina spring, where the traser appeared. this shows a lateral openness of the aquifer toward the grobnicko polje, and also toward the rjecina spring. 4, conclusion the rjecina river spring, due to its position and water quality, is an outstandingly suitable sourcc for the water supply of rijeka. it enables a gravitational inflow of high-quality water into the whole water-supply area. however, the cessation of act ivity for up to three months in the dry summers is a problem as during these dry periods the entire urban water supply has to be con­ verted lo the permanent coastal springs. th is conside­ rably increase production cost and creates problcms in the protecting of spring water quality (biondle & goa til, 1986). detailed hydrogeological mapping , geophysical explorat ion, exploratory boreholes, groundwater flow tracing and detailed measurements of hydrodynamic and geohydrochemical parame ters identified karst aquifers which arc active during rjecina spring inacti ­ vity. they indicated that the best aquifer conditions exist in a folded struc ture in thc second overthrust above the rjecina spring. this structure is composcd of lower cretaceous calcareous breccias and limestones. the measurements in the borehole sp-3 show a high water-level amplitude betwecn 352 and 475 m above sea level, water temperature lowering with depth, a considerable exchangc of groundwater under different hydrological conditions and connection with a zone of springs at the north-westcrn edge of the grobnicko po­ lje. this was a good indicator of the aquifer activity and justifies elaboration of the first phase of the project for water extraction and further aquifer exploration. it has been proposed that the explored karst aquife r can be tapped by a gal1ely from the rjecina river canybiondic. dllkaric. kllhla & l3iondic: hydrogeological bplor;)tioll of the rjecilla river spring ... 2<7 ~oundwater temperature cc) , 7.7 7.8 7.9 265 -i--i 255 245 235 ~ ;, '0 225 0o o .~ 215 " e o .5 205 ~ a § 195 ." ~ w 185 175 165 --spring --summer autumn .. . ---. winter 8.0 \ \t ". 155 .l----"----'--1 8.1 8.2 j' .. 8.3 fig. 9 diagram of the groundwater temperature var iations in the spring zone of grobnicko polje. on, so that the active part of the aqu ifer is interested, bu t above the recorded minimal g round water levels. global experience support that such "water mining" is no t to be recommended. such an intake construction might causc permanent harm to the aqu ifer, negatively affecting the zone of permanent coasta l spri ngs. an underground entrance into the aquifer above the levels of minimal water stages does not mean the avoidance of problems associated with high water stages. in any case a gravitation al dra inage of water from such construc­ tions would have to be insured. on the basis of all these and earlier exp lorations, a 1200 m-iong ga llery at an elevation of 355 m above sea lcvel can be proposed (figs. 4 & 5) . thi s woul d enter the massif from thc rjccina river canyon above the level of the rjecina spring, but needs to be further defined. past experiences has proved tha t any water construction in such he tero­ geneous karst underground requires constant reinterpre­ tation and design right up un til the final construction and test pumping. the final aqui fer geometry, water dynamics and possible volumes of water extraction must be defined '" '" .§. ~ ~ " '0 q, " 0 ." '" i': '" ~ .n 0 '" .c ~ .... 0 " 0 ." '" > '" uj ['conductivity (ms/cm) 1 0.265 0.270 0.275 0.280 0.285 0.290 0.295 424 414 404 394 384 374 364 354 344 / 334 324 f f v / v' !'fi / : f ./ / f f i f i /,' i r -i ! i ./ ---_ ... i ;/1 i i i ' 1.1'-, . spring summer autumn winter fig. 10 diagram of the groundwater conductivity variation s in the borehole sp-3. by additional hydrogeological, geophysical and geo­ chemical explorat ion , and by the drilling and monito­ ring of observation boreholes, as well as by test pump­ ing of production wells. 5. references biondle. b. (1988): tapping and protection of gro­ undwater in the adriat ic karst region related to the new conception of structures of dinarides.proce­ edings of the 21 st jah congress. 187-193, quil in, china. brondle. b. , goa ttl , v. & vulle, z. (1979): hyd­ rogeological investigation of watershed rjecina spring, grobnicko polje, zvi r and martinscica.pro­ ceedings of the 1st intern. symp. aboul groundwa­ lei' undp. 61-69, zagreb. biondle. b. & goa ttl , v. (1986): protection of groundwater in karst area of croatian littoral.pro­ ceedings of 19th iah congress, 112-120, karlove vary. mondlc, b., sarin, a., hertelendi, e., duka­ ric, f. hinic. v. hrvojic. e., goatti. v., ivicic, d., kapelj, s., korolija, b., sin­ ger, d., b[ondlc, r. & mesic, s. (1995): nati­ onal report for croatia.final report of eu cost 65 project "hydrogeological aspects of groundwater protection in karstic area", 65-87, bruxellcs. mondlc, b, mondlc, r. & dukaric, f. (1998): protection 01" karst aquifers in the dinarides in croa­ tia. environmental geology, 34/4, 309-3 i 9. boz[cev[c, s. (1973): contribution to the hydrogeo­ logy of the rjec ina spri ng. geol. vjesnik, 25, 277283. bozicevic, s. (1974): morpho[ogy of the rjccina spring watcr channcls.geo!. vjesnik, 27, 273-281, zagreb. ljeologla lroalica ~ufl herak, m. (1986): a new concept of geotectonics of dinarides.acta geo\., 16/1, 1-42, zagreb. herak , m. (1991): dinaridi. mobilisticki osvrt na gcnczu i strukturu (dinaridcs. mobi li stic view of the genesis and structurcs).acta geol. , 21/2, 35 117, zagreb. kuhta , m. (1998): speleo diving explorations of the rjccina spring.speleolog, 44/45, in print , zagreb. segota, t. (1968): sea leve[ changes in ho[ocen and younger wtirm. geographical bulletin , 30, 15-39, zagreb. sikic, d. & plenicar, m. (1975): osnovna geo­ loska karta sfrj 1:100.000. tumac za list liirska bistriea l33-89 (geology of ili rska bistrica sheet).­ institut za geol. istr., zagreb & geo!. zavod ljub­ ljana (1967), sav. geol. zavod beograd, 50 p. manuscript received apri l 14, 1997. revised manuscript accepted november 10, 1997. geologia croatica 45 115 -126 12 fig. zagreb 1992 udc 553.492.1:551.736 (497.13+497.15) scientific paper origin and depositional environments of the evaporite and carbonate complex (upper permian) from the central part of the dinarides (southern croatia and western bosnia) josip tišljar key words: evaporites, gypsum, anhydrite, early­ diagenetic dolomites, terrestrial breccias, coastal sabkha and playa environments, upper perm ian, dalmatia, lika, bosnia, dinarides the upper perm ian sedim en ts from central part of the dina ride s contain three main facies : 1.carbonates; 2.evaporites with early­ diagenetical dolomites and 3.clastic rocks (siltstones and sandstones) and one special rock typecarbonate cavity breccias. the carbonate facies include lagoonal and intertidallimestone, evaporite facies contain gypsum (originated by hydration of anhydrites), early-diagenetical dolomites and anhydrites deposited in coastal sabkha environment. the clastic rocks were deposited either fore-shore or playa to salt­ lake playa environments. the carbonate cavity breccias are interpretated as a terrestrial features, i .e. secondary surface products of physical and chemical weathering oftectonically disrupted carbonate-evaporite sediments. the upper perm ian evaporites and carbonates of the central dinarides are sediments deposited in evaporitic conditions arround the edges of an epeiric marine basin which existed in conditions of a general regressive tendency and permanent coastal seawards progradation. the upper permian evaporites of central dina ride s af!: comparable with evaporites from the bellerophon formation from the southern alps, italy. l. introductiqn the"permo-triasic"evaporites and accompanying sediments from the central part of the dinarides (central and northern dalmatia, and the neighbouring region between lika and sw bosniafig. l) have been a subject of extensive.geological investigations. the purpose of the investigations was to determine the age of evaporites and accompanying sediments, superposition and tectonic relationships with the surrounding rocks, minei=alogy, petrology and chemical composition, and also to define their depositional condi.tions and environments. this paper deal s oni y with the results of petrological and sedimentological investigations of carbonates and evaporites together with the interpretation of their origin, depositional environments and conditions. it is also a natural extention of the article written by šušnja.~a et al.(l992) in this vol. and as such is a part of the presenta­ tion of syntesis of the above mentioned extensive geo­ logical investigations. 2. geol..ogical setting and outline of stra tig raphy the-age of the.evaporites and-r.ccompanying sed.iments from the central part of the dinaride:: (central and northern ključne riječi: evaporiti, gips, anhidrit, ranodijagenetski do lomiti, terestičke breče, okoliši obalne sabkhe i pia je, gornji perm, dalmacija, lika, bosna, dinaridi gomjopermski sedimenti središnjeg dijela dinarida sadrže tri glavna facijesa: 1.karbona te; 2.eva~rite s ranodijagenetskim dolom i tima i 3.-klastične stijene (siltit i pješčenjak) te jedan poseban tip stijena šupljikave karbonatne breče. karbonatni facijes uključuje laguna me i pl imske vapnence, a evaporitni facijes se sastoji od gipsa (nastalog htdratacijom anhidrita), ranodijagenetskih dolomita i anhidrita taloženih u okolišima obalnih sabkhi klastične stijene su taložene ili u okolišima prednjeg žala i/ili u okolišima plaja do slanih jezera. šupljikave karbonatne breče su interpretirane kao teres tičke tvorevine, tj . kao sekundarni površinski produkti fizičkog i kemijskog trošenja tektonski razdrobljenih karbonatno-evaporitnih sedimenata. gomjopel'lnski evaporiti i karbonati središnjeg dijela dinarida su sedimenti taloženi u evaporizacijskim uvjetima duž rubnog dijela epikontinentainog morskog bazena koji je postojao u uvjetima opće regresivne tendencije i stalne progradacije obale u smjeru mora. po svojim sedimentacijskim značajkama ti se evaporiti mogu usporediti s evaporitima "belerofon form acije" u gornjem permu južnih alpa, italije. dalmatia, lika and sw.bosnia) has been a subject of some dispute: namely these sedi ments have ages ascribed in range from the permian (katzer, 1921; 1925) to the malm ian into the early cretaceous (šušnj ar et al., 1965; šušnjar, 1981). although the prevailing view was that the "perm o-triassic" and lower triassic are the likely ages but there was no real paleontological eviden~e to support this argument. podupsky (1963, 1973) regards that the deposition of evaporites occurred in the permian in an epicontinental environment, and that they do not belong to the marine lagoonal1p.positional cycle. herak (1973, 1983) together with the presented arguments in favour of the perm ian or "perma-triassic" a.se of the evaporites from dalmatia and lika, reflects to the possibility of their deposition in shall aw marine environments, although he does not exclude the possibility that the evaporite complex contains also units of different age associated with separated types diapiric movements. with the support of numero us palinological evidence šušnjara et al.(l992) have succeeded to precisely determine that the evaporite complex with accompanying sediments from central dalmatia belongs to the lower part-of the-late.p-ermian .~md .in the .wide .reg-ion of.sih in lika to the middle stage of the late perm ian. faculty of mining, geology and petroleum engineeringuniversity of zilgreb, pierottijeva 6, p.o.b 186, 41000 zagreb, croatia 116 geologia croatica 45 o so km ~~---c==~--k==d bosnia and herzegovina ' ....... '· ) o fig. l : map showing the location of the studied area of the upper perrnian evaporite complex from the central part of the dina ride s. slika l: karta područja istraživanja gomjoperrnskog evaporitnog kompleksa središnjeg dijela dinarida. '· ...... --->\ r"'\ tišljar: origin and depositional environments .... 3. sedimentological characteristics, origin and sediment ary environments of the upper permian ev aporite complex the permian sequences in central and northern dalmati a, lika and western bosnia (fi g. l) contain three main types of facies: 1.carbonate rocks (mainly limestones), 2.evaporites (gypsum and anhydrite) and early-diagenetic dolomites and, 3.clastic rocks, i.e. siltstones, sandstones, and very rarely conglomerates (see figs. l, 2 and 3 in the atricleby šušnjara et al., 1992, p. 96-99). special facies type are carbonate cavity breccias or the so-called "rauhwacks" ("porous carbonate brec~ias"šušnjara et al.,(l992). the superposing succession of the three main faci es types and facies of carbonate cavity breccia equally developed on all locations and is often indistinct due to soil and vegetation covering and intensive tectonic disruptance of the sequences. in general, however, šušnjara et al. (1992) state that evaporites are the o l dest facies and are succ~eded by clastic and/or carbonate facies and carbonate cavity breccias. under the general name "evaporites" here is encircled evaporite facies, i.e. gypsum with no macroscopically visible dolomite and with dolomite laminas and vuggy dolomicrites (seciton 3.2). outcrops with accurately determined direct synsedimentary contacts of carbonate and clast4: rocks were not observed due to soil cover and tectonical disturbances; this does not necessarily mean that these contacts and relationships do not exist. the relationship between evaporites and carbonate cavity breccias is more complex. although the breccias regularly occur immediately above evaporites, and rarely in association with carbonate rocks, their stratigraphic position is dubious since they are a weathering product of tectonically disrupted and leached rocks of the evaporite and/or carbonate faci es , and they also occur during the course of different chronostratigraphic units (section 3.3). 3.1 petrography and depositional environments of the carbonate facies the upper permian carbonate facies consists of stratified, and in places horizontally laminated, dark-gray and black kerogenous mudstones, pellets-bearing and/or ostracods­ bearing wackestones, and crystalline (microsparite) limestones rich in organic matter and pyrite. often they are more or less intensively late-diagenetically dolomitized or recrystallized. rarely this facies contains dolomites resulting from late-diagenetically dolomitization of wackestones and mudstones. sporadically are found dark­ gray kerogenous cryptocrystalline limestones, mudstones, and pelletoidal wackestones and packstones, rarely pelletoidal grainstones, which contain calcite pseudomorphs after anhydrite, or kerogenous ostracods-bearing mudstones/ wackestones with large, discoidal gypsum crystals (fig. 2) or with molds of gypsum crystals which are now occupied by secondary minerals: opal, chalcedony and/or quartz. the gypsum was formed initially by displacive growth 117 fig. 2: thin-section photomicrograph of kerogeneous ostracoda wackestone with large, discoidal gypsum crystals formed initially by displacive growth in a intertidal-supratidal sabkha environment. carbonate facies from elerovac; width of photograph = 7,5 mm (crossed nicols). slika 2 : kerogenski ostrakodni vekston s krupnim, diskoidaln im kristalima gipsa nastalim rastom u mulju plimskog do natplimskog sabkha okoliša. karbonatni facijes područja elezovac; širina slike = 7,5 mm (ukriženi nikoli). in carbonate mud in the lateral marginal intertidal-supratidal zone of lagoon which gradually passes into sabkha, i. e during the early phase of the regressive sabkha cycle ("gypsum mush"selley, 1988). limestones of the carbonate facies occurring in association with evaporites belong to sediments deposited in restricted shallow, hypersaline lag oo ns or in very shallow subtidal to intertidal environments of the regressive cycle. here together with fine carbonate sediment, qui te a large quantity offinegrained organic matter was accumulated. a part of the limestone from this facies was probably deposited as a contemporary lateral or younger facies together with coastal sabkha and playa deposits in a generally regressive cycle on the margin of an epeiric sea (fig. 3). in part they could have been deposited even after the coastal and terrestrial sabkhas ceased to exist, mainly laterally, in somewhat deeper, i.e. distant areas of an epeiric sea or a marine basin with a permanent narrowing tendency a re gression cycle (fi g. 3). the lagoons and shallow bays that existed there, due to the continuous fall of seawater, and its somewhat greater depth could not have been transformed into sabkhas, during the progradation of the coast or relative sea-level fall (fig. 3). 3. 2 depositional environments and origin of ev aporite facies ln numerous outcrops, drill cores and gypsum guarries it r.as been observed that no significant quantities or mac•· )scopically visible dolomite layers or laminae occur in the 1jwer portions of the evaporite facies. while in the higher st>,quences of the evaporite facies the dolomite beds occur freqt..ently, and also evaporite beds alternated with dolomite beds (fi g. 4 ), or tectonic dolomite-evaporite breccias which are not of synsedimentary origin (fi g. 5). these breccias originate by intensive tectonical crushing of the dolomite-anhydrite thin layer alternation. 118 sal t lake play a slano jezero plaja geologia croatica 45 cost al sabkha obalna sabkha ---ll)loo~regressive tendencyregresivni slijed fig. 3: idealized drawing of the upper permian depositional environments: l and la =carbonate facies; 2 and 2a = evaporite-dolomite facies and 3 = das tic facies. in some places may be ela s tic facies in l a and 2, too, and fan delta into the marine restricted shoals (not showing on the fig.). slika 3: shematizirani prikaz okoliša taloženja gomjopermskog karbonatno-evaporitnog kompleksa: l i la= karbonatni facijes; 2 i 2a = evaporitno-dolomitni facijes i 3 = klastični facijes. mjestimično la i 2 može biti i klastični facijes, a deltne lepeze su mogle biti formirane i u morskom zaštićenom plićaku (nije prikazano na slici). fi g. 4: gypsum with laminated thin bed of tectonicaly crushed early­ diagenetic dolomite. evaporite-dolomite facies from sinj area. slika 4: gips s tankim slojem tektonski razlomljenog· laminiranog ranodijagenetskog dolomita. evaporitno-dolomitni facijes područja labrovića kuća kod sinja. fig. 5: "dolomite-gypsum breccia" orip,inate by tectonicaly crushed thin-bedded dolomite-anhydrite (replacement by gypsum?) sabkha cycles. evaporite-dolomite facies from gypsum deposit mali kuk or in the kosovo polje. slika5: "dolomitno-gipsna breča" nastala tektonskim drobljenjem sabkha ciklusa sastavljenih od tankoslojevitih izmjena dolomita i anhidrita (potisnutog gipsom?). evaporitno-delomitni facijes, gipsolom mali kukor u kosovu polju. tišljar: origin and depositional environments .... at some sites (for example, gypsum quany "slane stine", drill cores from glavice, sinjsko polje) the evaporites contain only dolomite fragments or relicts of dolomite-evaporite breccia which has resulted from either intensive tectonical crushing, diapirism, and/or replacement of dolomite by anhydrite. often they contain, crumbledand broken, thin alternating laminae of dolomite and gypsum. numerous outcrops contain dolomite carrying isolated gypsum nodules or dolomite with cavites and fissures filled with secondary gypsum which resulted from hydration of anhydrite or with anhydrite and secondary gypsum. also gypsum occurs frequently em bedding dolomite layers, laminae, orrelics of laminated and strom atoli tic dolomite (figs.6, 7 and 8). the evaporites consist of either gypsum or anhydrite fig. 6: gypsum bed with relics of thin beded, organic matter-rich dolomicrite. gypsum origin by hydration of anhydrite that has replaced a dolomite mud stone host in coastal sabkha environment. evaporite­ dolomite facies from sinj; thin-section (crossed nicols), height of photograph = 3,3 mm. slika 6: gipsni sloj s reliktima tankoslojevitog, organskom materijom bogatog dolom ik rita. gips je nastao hidratacijom an hi drita koji je u sabkha uvjetima potiskivao dolomit. evaporitno-dolomitni facijes labrovića kuće kod sinja; visina slike = 3,3 mm (ukriženi nikoli). or both gypsum and anhydrite (figs. 4-10). normally, gypsum is bedded, internally thinly layered (3-8 cm) and consists of undulatory but roughly parallellaminae of light mosaic and dark gypsum. often it is characterized with the "enterolithic" folds. the gypsum occurs on the surface or near the surface, while anhydrite is found in deeper sections of gypsum fig. 7: gypsum with thin laminae of dolomicrite (part of bed folded into an enterolithic structure). gypsum is originated by hydration of sabkha anhydrite that have extensively replaced a laminated dolomite host. evaporite facies from kninsko polje, thin-section, width of photograph = 3,3 mm (crossed nicols). slika 7: gips s tankim laminama dolomikrita (dio sloja boranog u enterolitnu strukturu). gips potječe od hidratacije sabkha anhidrita koji je u sabkha okolišu potiskivao laminirani dolomit. evaporitni facijes kninskog polja, širina slike = 3,3 mm (ukriženi nikoli). quarries and boreholes, due to the fact that the gypsum is, in general, a secondary mineral formed as a result of anhydrite hydration (figs. 8 and 9). the hydration of anhydrite begins on the margins of anhydrite crystal cleavage planes and in tectonically disrupted and fissured zones, in shapes of fibrous gypsum veins. advanced degrees of anhydrite hydration are characterized with gypsum crystals that poikilitically enclose anhydrite relics, or gypsum crystals produce an intersecting mass of oriented crystals which enclose and centripetally replace anhydrite (figs.8 and 9). fig. 8: gypsum bed of the evaporite facies: thin-section showing more ·. relics of dolomicrite (dark) and anhydrite (blue-purpur grain) within the gypsum mass originated by anhydrite hydration. bistrica area, width of photograph= 3,3 mm (crossed nicols). slika 8: sloj gipsa iz evaporitnog facijesa: mikroskopski izbrusak pokazo je više relikata dolomikrita (tamno) i anhidrita (plavoljubičasto) unutar gips ne mase nastale hidratacijom anhidrita. područje bistrice, širina slike = 3,3 mm (ukriženi nikoli). complete hydration of anhydrite is manifested by homogeneous, fibrous gypsum crystals that sporadically contain isolated coroded anhydrite relics and very thin dark-grey, here and there yellow-brown laminae or bands of organic matter, pyrite or gypsum pigmented with fe120 fig. 9: thin-section of the evaporite facies anhydrite hydration in gypsum is more effective along cleavage plane; width of photogrph = 7,5 mm ( crossed nicols ). slika 9: mikroskopski izbrusak evaporitnog facijesa pokazuje hidrataciju anhidrita u gips koja je najintenzivnija duž pukotina kalavosti; širina slike= 7,5 mm (ukriženi nikoli). minerals. fibrous gypsum crystal aggregates sporadically contain coarser authigenic calcite or/ and less frequently secondary dolomite, and commonly early-diagenetic dolomicrite relics (figs. 6, 7 and 8). anhydrite hydration is increased with temperature and salinity decrease of pore water in evaporites. it is even enhanced after anhydrite ispenetrated by circulation of fresh (meteoric) water (murray, 1964). in our case the evaporites had been repeatedly intensively tectonically disrupted, crushed and faulted, and the hydration of anhydrite occlirred after their emplacement near or at the surface by tectonical and erosional processes. in other words they were subjected to the intensive influence of meteoric, surface and ground waters. some evaporites contain macroscopically visible dolomite layers (fig. 4 ). laminae or !amina relics and/or tectonically broken and brecciated thin layers of dolomite in shape of "dolomite-gypsum" breccia (figs. 5 and 10), although in most evaporites these dolomites are not observed macroscopically; they are regularly present in thin sections of evaporites (figs. 6, 7 and 8). dolomite layers typically are lenticular, and may be laterally contiimous for no more than 3 10 meters and laminae no more than a few cm. the most striking structure of the dolomite are long narrow tabular cavities, lensoid to avoid vugs 0,5-2 mm in diameter. they appear to be linked to solution cracks or to leached tube. the observed dolomite texture, structure and composition define them as either dolomicrite, dolo­ pelmicrite or stromatolite with desiccation cracks and/ or shrinkage cracks. all of these dolomites are supratidal early-diagenetical dolomites or evaporite dolomites originated in the same sedimentary cycle as anhydrite, i.e. in regressive sabkha cycles (flfstly as mud accumulation _ in a shallow subtidal or restricted lagoon at the margin of a wide sabkha and then as early-diagenetic dolomiti­ zation at the supratidal environment). evident alternating cycles of dolomite and gypsum (as a hydration product of anhydrite), have been preserved at many sites; although geologia croatica 45 the dolomite and gypsum (or anhydrite) beds and thicker laminae have been intensively tectonically brecciated. these cyclic alternations can be interpreted as b and c members of regressive sabkha cycle similar to sabkha cycles in arab­ darb formation (wood & wolfe, 1969). evaporites without distinctly macroscopically visible dolomite layers and laminae ("pure evaporites") usually contain dolomite (observed in thin sectionsfigs. 6, 7 and 8) in shapes of thin, broken and "folded" laminae, termed "enterolithic structure" or "enterolithic folds" (bosellini & hardie, 1973) and irregular clusters or aggregates. dolomite occurences in these evaporites are actually relics of dolomite layers and laminae belonging to the b member of the sabkha depositional cycle preserved after "~nterolithic folding" processes, i. e. by several periods of strain by hydration of anhydrite to gypsum and dehydration of gypsum to anhydrite. diapiric uplift, and early-diagenetical anhydrite replacement of dolomite in sabkha environment is very strong and frequent (shearman, 1966). the processes qf tectonical fracturing and anhydrite and/or gypsum replacement of dolomite here must be also taken into account the relatively small amount of dolomite in "pure evaporites" can be the consequence of displacement and up lift of plastic evaporite strata by diapirsm, which separates them from the brittle undisplaced carbonate members of sabkha cycles. the essential evaporite characteristics together with the petrological and sedimentary interpretations of associated dolomi.:es, allow the interpretation of depositional environments of evaporites as follows. while evaporites associated with early-diagenetical dolomites exhibit principa! features of the origin coming from coastal sabkha depositional environments, the evaporites without macroscopically visible dolomite or with dolomite which occurs in shapes of thin broken laminae, pleated bands and relics, cannot be interpreted fig. 10: tectonicaly crushed dolornicrite replaced by veins of gypsum, respectively. small relict of anhydrite (yellow) in dolomicrite point at sabkha cycle. evaporite-dolomite facies from bistrica area, thin­ section, width of photograph = 7,5 mm (crossed nicols). slika l 0: tektonski razdrobljen i dolomikrit po pukotinama in ten zi vno potiskivan žilama gipsa. u dolornikritu se nalaze i sitni relikti anhidrita (žuto) koji ukazuju na dolomitno-anhidritni sabkha ciklus. evaporitno­ dolomitni facijes područja bistrice, širina slike =7 ,5 mm (ukriženi nikoli). tišljar: origin and depositional environments .. .. unambiguously with respect to depositional' conditions and environments. the present surface gypsum evaporites (products of hydration of anhydrite), were deposited in evaporation conditions around the edges of an epeiric marine basin, i. e. in the large belt on desert carbonate-shoreline coastal sabkhas, which existed in the conditions of general regressive tendency and permanent coastal pro gradation originated by continua! sea-level fall (fig. 3). these conditions ended with the development of long-lasting sabkha and playa environments, and finally with lake (either salty or brakish water), river and land environments. it is evident that the intertidal and supratidal zones (clastic and carbonate) have been prograding seawards, thus making the sediments of these facies diachronous (fig. 3). in restricted shoals, lagoons and intertidal environ­ ments contemporaneous limestone deposition occurred, while on the fore-shore and shore-face with dominanting siliciclastic sediments (i. e. siliciclastic shore-lines), playas and lakes (salt, brakish and/or fresh water) with small deltas and rivers, clastic deposition prevailed (fig.3). these clastic sediments, especially deposited in fore-shore, playa and salt lake environments, often contain cube molds ofleached hali te crystals which originally precipitated in dry periods of semi-arid or arid climate conditions. although upper permian evaporite outcrops, with a complete "regressive sabkha cycle" (wood & wolfe, 1969) were not found in the central dinarides area, frequently b and c members, or a member succesion (section 3.1), of the sabkhacycle were observed. thus, we can conclude that the evaporites which· contain earlydiagenetical dolomites were formed in coastal sabkha environments (fig. 3). however, massive evaporites, which contain only dolomite relics, were probably formed in similar conditions of high evaporation on marginal parts of a shallow epeiric sea with a permanent regression tendency and development of long-lasting sabkhas. namely, in these evaporites, in spite of their thickness (due to diapirism), absolutely no observation was made of laminated altemations of carbonates enrichment with organic matter, anhydrite and halite. the bulk of evaporites deposited in subtidal and deeper marine environments (lagoons, bays et e.) are either distinguished by previously mentioned regular thin laminated alternations inside a few hundred meters thick, continuous evaporite sequences or they belong to the "handed anhydrites" or "varve anhydrites" rich in organic matter, "stinkenkarbonate", and altemations with hali te (richter­ bernburg, 1955; schreiber, 1986). as it is known, hali te deposits are uncommon or fail in carbonate-anhydrite sabkha evaporite sequences (selley, 1988). since, in our ·case such evaporite features have not been observed, this ex<;ludes the interpretation of their origin in subtidal or deeper marine environments. the comparatively small amount of dolomite and absence of complete sabkha cycles (a-phase: algallimestone homogeneous, b-phase: laminar and bird's,eye dolomite algal mat dolomite, and c-phase: nodular anhydrite; wood & wolfe, 1969) in the upper permian evaporites 121 of the central dinarides, especially in deeper portions of evaporite sequences, can be interpreted as: sabkha anhydrites have been deposited in long-lived sabkha environments with semi-arid to arid climate in the c-phase of the regressive sabkha cycle with high concentrations and influx of ca-sulphates, and in which anhydrite more or less completely replaces dolomite formed in b-phase; displacement by diapirism from the primary sabkha cycle succession of evaporite matter, without any significant up lift of carbonates, resulted in concentration of evaporite; due to intensive tectonical activity the brittle carbo­ nate beds (i.e. b dolomite member of sabkha cycles) were severly disrupted and milonitized, and their remains were later more or less completely replaced by gypsum. due to leaching of gypsum on the surface of outcrops, dolomite remains are repeatedly concentrated and formed either as "dolomite-gypsum breccias" or "rauhwackes"cavity breccias. thus we can assume that one, two or all the three processes had an important role in various periods of geological history of central dinaric upper permian evaporites and associated sediments. 3.3 origin of carbon a te ca vity breccias carbonate cavity breccias or the "rauhwackes" often go together with evaporites in various and somewhat indistinct relationships. although the problem of their stratigraphical connection with the evaporite and carbonate facies remains un defined, due to more breccia generations ranging from the late permian and pre-neogene to the quartemary (šušnjara et al., 1992) and also to the type of their development, the observed features imply a similar or even identical origin. they are highly porous, cellular, full of small holes, cavity breccias, which macroscopically, here and there resemble travertine. breccias contain various amounts of not sorted, angular fragments with corroded surfaces and edges, and also different amounts of cement (figs. ll and 12). the fragments ofpemuan limestones, early-diagenetical dolomites and evaporites predominate. the dolomite fragments are usually more or less dedolomitized and evaporite fragments fully or partially leached (large cavities in breccia, figs. ll and 12). the cement consists of cryptocrystalline to macrocrystalline laminar, pisoid-like or speleothem-like calcite accumulation pigmented with fe-oxides and hydroxides, and impurites of siliciclastic material (fig. 12). not only did the leaching of evaporite fragments occur, but also dedolomite fragments from the latter, friable dedolomitized mass could have been mechanically and chemically removed, and the remained molds-vugs could be subsequently partialy or sometimes completely filled with calcite cement mostly this was the reason why the breccia had cellular and cavity-like structures and why the leaching of rock fragments usually occured after they had been partially or completely cemented into breccia (figs. ll and 12). the leaching usually had little or no figs. ll( above) and 12 (below) : thin-sections of the carbonate cavity breccia: the evaporite and dolomite fragments and vu gs and m olds of leached fragments; microcrystalline and pisoid-like or calcrete cement around of the fragments and vugs. sinjsko polje; width of photograph= 7,5 mm. slika ll (gore) i 12 (dolje):mikroskopski izbrusci karbonatnih šupljikavih breča: fragmenti evaporita i dolomita i šupljine nastale izluživanjem pojedinih fragmenata; mikrokristalasti i pizoidni kalcitni cement oko fragmenata i šupljina. sinjsko polje, širina slike= 7,5 mm. effect on the cement (fig. 12). cavity breccias are definitly not of marine origin but they exhibit distinct terrestrial features. their occurrence on elevated surfaces of hills, as well as their discordant overlapping of underlying evaporite or carbonate deposits, regardless of the position of footwall beds, composition and structure, imply that they are secondary products of physical and chemical weathering of tectonically disrupted upper permian evaporite and carbonate sediments. whether it was due to a terrestrial phase at the and of permian, or a post-permian tectonical up lift and surface emplacement ofpermian evaporite and carbonate sediments, the sediments were weathered in terrestrial condition::-. the products of such weathering alterations were carbonate cavity breccias. the weathered products, beings either of semi-arid to arid climate with scarce rainfals and intensive evaporation, or meteoric and pore waters saturated with ca-hydrosgen­ carbonate, were gradually cemented with crust-like to pisoid­ lik:e and speleo them-like calcite cement into more-or less compact breccia. due to teaching of evaporite and dedolomite fragments, cavities develop in the breccia thus giving them cellular and/or cavity appearance. intep.sive geologia croatica 45 dedolomitization is enhanced by high ca content of pare solutions (i. e. low molar mg/ca ratio) which again is linked with dissolution and teaching of gypsum. this can also be an explanation why the cavity breccias or "rauhwackes" usually occur in association with the carbonate-evaporite facies. 4. discussion and conclusions although there is a limited number of large and for study favourable outcrops that exhibit clear relationships between vertical succession and lateral transition of the three main upper permian facies, i. e. carbonate, evaporite and clastite facies, the interpretation of conditions and environments of deposition and origin of each individual facies and the existence of the general regressive cycle in the upper permian, allows for a general interpretation concerning tj.!e conditions and environments·of deposition. the relation between the deposition of clastites and evaporite conditions is imp lied by occurrences of the hali te m olds inside clastite units from v rl ika and knin (sća vničar, b., 1973). on the basis of lithological characteristics of clastites from the surrounding areas of drniš and vrlika (central dalmatia; iv anović et al.,l971), there is correlation with the top part of "the groeden facies" (after groedental =val gardena) from the wider region of the dinarides. taking into account the fact that during the late permian the general permian regressive cycle was at its peak, and that narrowing of the epicontinental marine depositional basin was in constant progress, that the upper perm ian limestones belong to lagoonal and intertidal environments -often to the starting a member of the regressive sabkha cycles that also the evaporite facies which major characteristics of sabkha sediments, and that the clastic facies exhibit transition from off shore, shore face, fore shore, over p laya and salt lake e:wiron-ments to alluvial environments, these characteristics show general depositional model on fig. 3. in general, during the late pef!llian in the present day central parts of the dinarides, assuming a more or less continuous regressive tendency, various deposition conditions and environments existed and were defined by the existence of a shallow epicontinental sea with a very differentiated coastline, bays and lagoons. also, due to the general regressive tendency, this concerns wide zones of coastal sabkhas which gradually pass into playas and/ or salt lakes with or without alluvial sedimentation and which finally pass into terrestrial environments (fig. 3). it appears that, simultaneously at different places, deposition of lagoonal and intertidal sediments (carbonate facies), supratidal and sabkha sediments (early-diagenetical dolomites and evaporites) was possible. this was also accompanied by clastic deposition in coastal environments, playa and salt lake environments with or without river mouths and deltas, and partially by river depositional environments (clastic facies) and the common terrestrial e'lvironments (upper perm ian cavity breccia). in case of a generally continuous regressive succession, exhibiting tišljar: origin and depositional environments .... probably with more or less positive or negative fluctuation, the normal facies succession would be: carbon te facies evaporite and/or clastic facies (fig. 3). since depositiona1 environments are not oni y under the influence of the general regressive tendency, which plays an important part in development of large lateral differences of facies, but are also under the influence of rapid changes of deposition, of periodical sea-level fluctuations, global and local synsedimentary tectonics, autocyclicity, coast and tidal flat progradation, climate variation, alternation of semi­ arid to arid and rainy periods, various lateral and vertical facies succession from one locality to another have resulted. for example, in the central part of the velebit mt. (oštarije near gospić) in the late permian were deposited only peri tidal carbonates withour evaporites in the following succession: 1.subtidal to lower intertidal fusuline-bearing limestones; 2.-supratidal dolomites; 3.black organical­ rich mudstone,s and bioclasdc; packstones deposited as organical-rich mud in a restricted shallow bay and/or on the edge of a shallow lagoon between large supratidal areas, and 4 .supratidal dolomites with reddish-brown or grey shale intercalations in the uppermost part (tisljar et al., 1991). from the presented data and schematic diagram (fig. 3) it is evident that during the late permian in the wider region of the central parts of the dinarides various deposition environments existed with both graduallateral and vertical sequence transitions. after and/or during shalow marine 11mestone and sabkha evaporite deposition together with associated early-diagenetic supratidal dolomites in the generally regressive regime and locally varying conditions of time, gradually ceased to exist shallow marine en v ironments with carbonate deposition and coastal sabkhas with dolomite and evaporite accumulation. these deposition environments were either gradually or abruptly replaced by clastic deposition in coastal, playa or (salt, brackish?) ephemeral lake or river environments, and finally, by terrestrial conditions. the latter were at their peak in the terminanting stages of the perm ian. the reestablishment of the shallow marine deposition regime occurred at the beginning of the triassic. the correlation of the upper perm ian evaporites from the central part of dinarides compared to the similar northern and western european evaporites, for example "the zechstein evaporites" from poland, germany, netherlands and denmark, due to lithological composition, depositional environments and conditions of upper permian evaporites from the dinarides excludes the application of the first (z-1) and second (z-2) "zechstein evaporite deposition cycle models". the third (z-3) "zechstein cycle" model of deposition (schreiber, 1986), however, is partially applicable. to be more precise, the concluding sec;.uences of the third (z-3) cycle including the deposition of evaporites in the evaporite basin, has a basin reducing tendency accompanied by shallowing. only anhydrite and early­ diagenetical dolomite in sabkhas and limestone and gypsum in the sub tidal to intertidal zones developed here whereas halite and k-mg-salt deposition are not present in these environments. 123 the lithological characteristics, sabkha cycles and general depositional environment of the upper permian evaporites from the dinarides are quite similar to the upper permian evaporites of the bellerophon formation from the southern alps, italy. the bellerophon evaporite cycle is interpreted as a regressive cycle which was formed in an arid marginal marine environment by a prograding tidal flat building sea ward over a shallow subtidallagoon and leaving behind an exposed sabkha (bosellini & hardie, 1973). acknowledgements this work was partly supported by the enterprice ina­ naftaplin, zagreb and the institute of geology, zagreb. the manuscript was read by dr. tadeus peryt and his comments led to considerable improvement in the presentation. 5. references bosellini, a. & hardie, l.a. (1973): depositional theme of a marginal marine evaporite. sedimento­ logy, 20, 5-27, oxford. herak, m. (1973): some tectonical problems of the evaporitic area in the dinari des of croatia. g eo l. vjesnik, 26, 29-40, zagreb. herak, m. (1983): someideasanddilemmasconceming the genesis and tectonics of adriatic and peri-adriatic areas.in: babić,lj. & jelaska, v.: contri­ butions to sedimentology of some carbonate and clastic units of the coastal dinarides.i.a.s.41 h regional meeting exurs. guide-book, 7-11, split. iv anović, a., sća vnićar, b., sakać, k. & gusić, i. (1971) : stratigrafski položaj i petrografske karakteristike evaporita i klas tita okolice drniša i vrlike u dalmaciji. geol. vjesnik, 24, 11-33 , zagreb. katzer, f. (1921): pregledna geološka karta bosne i hercegovine, list banja luka. m 1:200.000, sarajevo. ka tzer, f. (1925): geologie bosnies und der herzegovina geol. zavod sarajevo, 1-480 (ih), 481-560 (lih), sarajevo. kinsman, d.j.j. (1965): gypsum and anhydrite of recent age, trucial coast, persian gulf.in: rau, j.l. (ed.): second symposium on salt, 1.north ohio geol. soc., 302-326. kinsman,dj.d. (1%9): modesofformation,sedimentary association and diagnostic features of shallow­ water and supratidal evaporites.bull. am. assoc. petrol. geol., 53, 830-840, tulsa. murray, r.c. (1964): origin and diagenesis of gypsum and anhydrite.j. sediment. petrol., 34, 512523, tulsa. patterson,r.j. & kinsman, d.j.j. (1981): hydro­ logic framework of a sabkha along the persi an gulf.bull. am. assoc. petrol. geol., 65, 14571475, tulsa. 124 podubsky, v. (1963): regionalne karakteristike geneze i geotektonskog položaja gips-anhidritskih ležišta zapadne bosne i hercegovine i hrvatske. geol. glasnik, 7, 161-167, sarajevo. podubsky, v. (1976): gips i anhidrit.u: mineralne sirovine bosne i hercegovine, knj. ii, ležišta nemetala, 328-338 geoinženjering, sarajevo. richter-bernburg, g. (1955): uber salinare sedimentation.z. dt. geol. ges., 105, 593-645, stuttgart. richter-bernburg, g. (1957): isochrone warven im anhydrit des zechstein.geol. rdsch., 49, 132-148, stuttgart. schreiber, b.c. (1986): arid shorelines and evaporites. -in: reading, h. g. (ed.): sedimentary environ­ ments and facies.blackwells publ., 189-228, oxford. selley, r.c. (1988): applied sedimentology.acad. press,446 p. london san diego, new york, boston, shearman, d.j. (1966): origin ofmarineevaporites by diagenesis.trans. inst. min. metali., b., 75, 208-215. šćavničar, b. (1973): kalupi kristala kamene soli (halita) u klastitima na području vrlike i knina.­ geol. vjesnik, 26, 155-157, zagreb. šušnjar, m. (1981): genetski faktori i geološke geologia croatica 45 okolnosti mobili teta i dijapirizma s osvrtom na imobilna i mobilna stanja kalcijsko-sulfatnih naslaga u prostoru dinarida.nafta,1-221, zagreb. !iušnjar, m., bukov ac, j., marinčić, s. & savić, d. (1965): stratigrafija gipsnih naslaga unske doline i korelacija s poznatim evaporitnim naslagama i popratnim facijesima u primorju, dalmaciji, lici i zapadnoj bosni. acta geol., 5, 407-422, zagreb. šušnjara, a., sakač, k., gabrić, a. & jelen, m. (1992): upper permian evaporites and associated rocks of dalmatia and borderline area of lika and bosna.geologia croatica, 45, 95-114, zagreb. tišljar, j., vlahović, 1., sremac, j., velić, 1., veseli, v. & stanković, d. (1991): excursion a velebit mt., perm ian j urassic. -in: velić, 1.& vlahović, i. (eds.): some aspetcs of tlre shallow water sedimentation on the adriatic carbonate platform (permian to eocene). excursion guide-book at the second int.symp. on the adriatic carbonate platform, zadar, may 1991., l-50,zagreb. wood, g. v. & wolfe, m. j. (1969): sabkha cycles in thearab/darb formation off the trucial coast of arabiasedimentology, 12, 165-191, amsterdam. geneza i okoliši taloženja gornjopermskog karbonatnog i evaporitnog kompleksa središnjeg dijela dinarida (južna hrvatska i zapadna bosna) j. tišljar u ovom radu su prikazani rezultati petroloških i sedimentoloških istraživanja karbonatnih i evaporitnih sedimenata, interpretacija geneze, uvjeta i okoliša taloženja evaporita i pratećih sedimenata "permo-trijasa" središnjeg dijela dinarida (srednja i sjeverna dalmacija i granično područje između like i jugozapadne bosne -sl. 1). po tome je ovaj rad normalni nastavak na rad šušnjara et al. (1992) s kojim čini dio cjeline prezentiranja rezultata kompleksnih geoloških istraživanja "permo-trijaskog" kompleksa središnjeg dijela dinarida. rezultati se odnose na područja istraživanja prikazana na sl. l i na geološkim kartama sl. 2 i 3 u radu šušnjara et al. (1992). brojnim palinološkim dokazima šušnjara et al. (1992) su utvrdili da "permo-trijaski" evaporitni kompleks s pratećim sedimentima središnje dalmacije pripada gornjem permu (donji dio gornjeg perma), a ~ireg područja srba u lici srednjem katu gornjeg perma. gornjopermski sedimenti središnje i sjeverne dalmacije, like i zapadne bosne su zastupljeni s tri glavna facijesa: 1.karbonatima; 2.evaporitima (gips, anhidrit) s ranodijagenetskim dolomitima i 3.klastitima, tj. pelitima, siltitima, pješčenjacima i vrlo rijetko konglomeratima (vidi sl. l, 2 i 3 u radu šušnjara et al.,l992 str. 96-99). poseban facijes su karbonatne šupljikave breče ("rauhwacke"). superpozicijski slijed ta tri facijesa i šupljikavih breča nije svugdje isti, a niti potpuno jasan zbog pokrivenosti terena i intenzivne tektonske poremećenosti naslaga. općenito su, međutim, najstariji evaporiti, a na njima leže klastiti i/ili karbonati ili karbonatne šupljikave breče (šušnjara et al.,l992). odnos evaporitnog facijesa i karbonatnih šupljikavih breča je složeniji jer su breče terestičke tvorevine nastale na površini zemlje u više različitih kronostratigrafskih jedinica. nepostojanje većeg broja izdanaka s jasnim međusobnim vertikalnim slijedom i jasnim bočnim odnosima triju glavnih facijesa, kao i činjenica da uvijek ne postoji egzaktno utvrđeni odnos tih facijesa u vremenu i prostoru, stvara znatne poteškoće pri općoj interpretaciji uvjeta i okoliša taloženja gornjo-permskih sedimenata. karbonatni facijes gornjeg perma se sastoji od dobro slojevitih, mjestimice horizontalno laminiranih, tamnosivih i crnih vapnenaca bogatih kero genom, uglavnom madston do vekston tipa. nerijetko su manje ili više intenzivno y.asnodijagenetski dolomitizirani ili rekristalizirani. rjeđe se u tom facijesu nalaze i kasnodijagenetski dolomiti nastali dolomitizacijom vekstona i madstona. vapnenci mjestimice tišljar: origin and depositional environments .... sadrže pseudomorfoze kalcita po anhidritu. kerogenski ostrakodni madstoni koji sadrže krupne kristale gipsa (sl. 2) ili kalupne šupljine kristala gipsa, koji su se izluči vali u karbonatnom mulju u bočnim rubnim plinskim dijelovima laguna koje postupno prijelaze u sabkhe (sl. 3) i to u početnoj fazi regresivnog sabkha ciklusa ("gypsum much"selley, 1988), su tipični bočni ekvivalenti potplimsko-plirnske faze sabkha ciklusa, tj. član a sabkha ciklusa taloženog u plitkom potplimskom do plimskom okolišu s povišenim salinitetom i stalnom evaporizacijom. dio vapnenaca tog facijesa je vjerojatno taložen kao istqvremeni bočni ili mlađi facijes sa sabkha i plaja sedimentima u istom, općem regresivnom ciklusu na rubnim dijelovima epikontinentalnog mora (slika 3). , evaporitni facijes na mnogobrojnim izdancima, bušotinama i u gipsolomima pokazuje da se u njegovim dubljim dijelovima uglavnom nalaze evaporiti bez značajnijih pojava ili makroskopski vidljivih prosio jaka dolomita, a da se u vršnim dijelovima evaporitnog facijesa obično s evaporitima pojavljuju pro~lojci laminiranih dolomita (sl. 4), nekontinuirane tamine dolomita u evaporitu (sl. 6) ili dolomitno-evaporitn3 breče nastale naknadnim tektonskim, a ne sinsedimentacijskim procesima drobljenja proslojaka dolomita i evaporita (sl. 5 i 10). najčešći su slojeviti i laminirani gipsevi u kojima se pojavljuju proslojci, tamine ili relikti laminiranih i stromatolitnih dolomita (sl. 6, 7 i 8) s tzv. "enterolitičkim boranjem" (bosellini & hardie, 1973). premda po obliku vrlo slična tektonskim deformacijama, ta su "enterolitička boran ja" ili tzv. "enterolithic folds" nastala kemisjkim promjenama volumena sedimenta uslijed 'stezanja i rastezanja proslojaka i slojeva evaporita pri procesima hidratacije anhidrita u gips i dehidratacije gipsa u anhidrik naime, pri hidrataciji anhidrita u gips, tj. primanju vode, povećava se volumen za cca 38% što,jasno, izaziva snažna naprezanja posebice kad se taj reverzibilni proces više puta po~avlja tijekom geološke povijesti. glede strukture i sastava dolomiti pripadaju dolomikritima, dolopelmikritima ili dolomitnim stro­ matolitima s desikacijskim pukotinama ili pukotinama stezanja (shrinkage cracks) te šupljinama otapanja. kod evaporita u kojima makroskopski obično nije moguće zamijetiti dolomitne proslojke i tamine ("čisti evaporiti") dolomit je, kako to pokazuju mikroskopske analize, i tu redovito prisutan obliku tankih, raskinutih i plisiranih ("boranih") jamina, gnijezda, grudastih relikata ili nepravilnih nakupina i agregata (sl. 5, 6 i 7). sve su to ranodijagenetski ili evaporitni dolomiti nastali u istom sedimentacijskom ciklusu s anhidritom u rubnim dijelovima prostranih sabkhi koje su zbog sužavanja marinskogbazena progradirale preko potplimskih okoliša u smjeru mora (sl. 3). usprkos snažnog tektonskog lomljenja u gipsevima se još mogu zapaziti cikličke izmjen'e'dolomit-gips koje odgovaraju članovima b i e sabkha ciklusa sedimentacije. evaporiti su zastupljeni gipsom ili anhidritom ili gipsom i anhidritom (sl. 2-10). gips se obično nalazi na površini ili blizu površine, a anhidrit u dubljim di jelo vima gipsoloma ili u bušotinama jer je gips pretežnim dijelom ovdje 125 sekundarni mineral nastao hidratacijom anhidrita, kako je to jasno vidljivo u mikroskopskim izbruscima (sl. 8 .i 9). hidratacija anhidrita je uvjetovana opadanjem temperature i smanjivanjem saliniteta parnih voda sadržanih u evaporitima, osobito nakon što su anhidriti došli u doticaj sa slatkom oborinskom vodom. u našem slučaju gdje su evaporiti višekratno intenzivno tektonski lomljeni, drobljeni i rasjedani, očigledno je da je hidratacija anhidrita u gips nastupila nakon što su evaporiti tektonikom, dijapirizmom i erozijom dospjeli vrlo blizu površini ili na samu površinu gdje su bili izloženi jakom utjecaju oborinskih i slatkih površinskih i podzemnih voda. evaporiti, koji su danas na površini zastupljeni gipsom nastalim hiđratacijom iz anhidrita, su taloženi u evaporitnim uvjetima u rubnim dijelovima epikontinentalnog marinskog bazena koji je zbog opće regresivne tendencije i permanentne progradacije oba:ie, odnosno stalnog povlačenja mora, završavao formiranjem i duže vremena održavanjem sabkha i plaja uvjeta (sl. 3). takvi okoliši su egzistirali na velikom prostoru duž prostran og i širokog područja uz stalne bočne migracije. tu su u rubnim dijelovima mora mogle biti veće ili manje lagune, zatvoreni pličaci, sabkhe i slane bare s visokom koncentracijom ea-sulfata koje su općom tendencijom smanjivanja marinskog područja, tj. općom regresijom i progradiranjem obale prema moru, postupno prelazile u natplimske i priobalne sabkhe i vjerojatno kontinentalne sabkhe i slana jezera sa stvaranjem ranodijagenetskih dolomita i nodulamih anhidrita. bočno u plitkim lagunama i plimskoj zoni tal oženi su vapnenci, a na prednjem žalu (foreshore) i obalnom licu (shore face) s prevladava jućim siliciklastičnim materijalom, kao i plajama\ i oslađenim jezerima, klastični sedimenti u ko jima se tijekom sušnih razdoblja izlučuje halit koji danas nalazimo u klastitima u obliku kalupa kubičnih kristala. evaporiti, premda imaju veliku debljinu (dijapirizam, tektonika ?), nigdje ne sadrže debele pakete laminacijske izmjene karbonata, anhidrita i hali ta. naime, većina evaporita taloženih u marinskim okolišima s nešto dubljom vodom (lagune, zatjevi i sl.) se odlikuje spomenutom pravilnom tanko lam~niranom izmjenom unutar kontinuirane debljine evaporitnih sedimenata od više stotina metara ili pak pripada tzv. "trakastim anhidritima", odnosno "v arven anhidritima" bogatim organskom supstancijom i izmjenom s halitima (riehter-bernburg, 1955; 1957; sehreiber, .1986). kako takvi evaporiti u našem slučaju nisu nigdje nađeni, taj način njihovog mogućeg postanka je isključen iz ove interpretacije. razmjerno mali udio dolomita i · nepostojanje kompletnih sabkha ciklusa: vapnenac-dolomit­ anhidrit u gornjopermskim evaporitima, osobito u dubljem dijelu evaporitnih naslaga, moguće je objasniti na slijedeći način: sabkha anhidrjti su pretežno nastali u dugotrajno postojanim sabkha uvjetima e faze regresivnog sabkha ciklusa s visokom koncentracijom i donosom ea-sulfata u kojima je anhidrit manje-više potpuno potisnuo dolomit; dijapirizmom su iz primarne sukcesije sabkha ciklusa bile kretane uglavnom samo evaporitne mase a ne i značajnije količine karbonata (vapnenci i dolomiti) što banak et al.: late pleistocene climate history of the baranja loess plateau – evidence from the zmajevac loess-paleosol section (northeastern croatia) 411  ab stra ct the zmajevac loess-palaeosol succession (lps) of the northeastern baranja loess plateau is exposed along the southern slope of bansko brdo, on the western bank of the danube river. the investigated 17.5-m-thick section shows 4 palaeosol, 1 loess-like and 6 loess horizons. their integrative palaeoenvironmental analysis combines quantified data from the mollusc record, magnetic susceptibility, grain-size, calcimetry and mineral abundances to reconstruct the pattern of regional palaeoclimate evolution. this result combined with infrared optically stimulated luminescence age estimates by galović et al. (2009) enabled correlation of the depositional units to middle to the late pleistocene marine isotope stages (mis) 6 to 2. magnetic susceptibility measurements show strong peaks in the palaeosol horizons pointing to increased concentrations of pedogenic ferrimagnetic minerals. sedimentological and mineralogical parameters are in good agreement with other pannonian basin lps. terrestrial gastropod palaeoecology based on 1705 specimens of 13 species counted from loess and loess-like horizons documents cyclic transitions between cryophilous to cold resistant and mesophilous to thermophilous assemblage types. whereas helicopsis striata, arianta arbustorum and chondrula tridens are common throughout the succession, the typical loess representatives pupilla sp., vallonia tenuilabris and columella columella are abundant only in certain horizons. nevertheless, species tolerating open and dry habitats are abundant throughout the succession. the faunal spectra for the samples prove the dominance of transitional palaeoecological assemblage types, whereas uniformly defined types are rare. one of these, the columella columella assemblage from the base of the section proved to be indicative of the penultimate glacial maximum. keywords: mollusc palaeoecology, magnetic susceptibility, grain-size, modal analysis, loess, climate change, danube, croatia late pleistocene climate history of the baranja loess plateau – evidence from the zmajevac loess-paleosol section (northeastern croatia)  adriano banak1, oleg mandic2, marijan kovačić3 and davor pavelić4 1 croatian geological survey, department for geology, sachsova 2, hr-10000 zagreb, croatia; (abanak@hgi-cgs.hr) 2 geological-paleontological department, natural history museum vienna, burgring 7, a-1010 wien, austria; (oleg.mandic@nhm-wien.ac.at) 3 department of mineralogy and petrology, faculty of science, university of zagreb, horvatovac 95, hr-10000 zagreb, croatia; (mkovacic@geol.pmf.hr) 4 faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, hr-10002 zagreb, croatia; (davor.pavelic@rgn.hr) doi: 104154/gc.2012.30 geologia croatica 65/3 411–422 6 figs. 2 tabs. zagreb 2012 geologia croaticageologia croatica 1. introduction loess is terrestrial clastic sediment, composed predominantly of silt-size particles, formed by the accumulation of wind-blown dust (pye, 1995). the pleistocene loess deposits show two main genetic types: (1) loess formed under periglacial conditions, commonly in front of the ice caps and (2) loess built up by small particles formed in the mountain areas. the second type of loess is present in the study area and also in the wider region (marković et al., 2005, 2008, 2009; galović et al., 2009, 2011; smalley et al., 2011, wacha & frechen, 2011). actually, loess covers up to geologia croatica 65/3geologia croatica 412 10% of the world’s surface area (pécsi, 1968), and is usually inter-bedded with soil horizons. such successions provide very detailed terrestrial records of pleistocene climatic fluctuations (kukla, 1987; guo et al., 2002). pleistocene sediments are widespread in croatia covering about 35.7% of its territory (bognar, 1976). in the southern pannonian basin (northern croatia) they dominantly cover large continuous areas, whereas in the dinaride mountains and adriatic islands (southern croatia), pleistocene deposits are restricted to small areas. aeolian silt and sand were blown into the lowland steppe, lakes, marshes and swamps (bačani et al., 1999). the region of baranja in northeastern croatia (fig. 1) is almost completely covered with pleistocene and holocene sediments. in particular, some of the thickest loess successions of croatia are exposed along the danube river. the total thickness of these loess and loess-like deposits probably exceeds 50 m. loess-palaeosol successions of baranja and northeastern croatia have long history of investigation (wacha & frechen, 2011 and references therein). malez (1965) analysed periglacial phenomena in eastern croatia. rukavina (1983) investigated loess-palaeosol successions and their mollusc fauna, providing an overview on warm periods in the late pleistocene of northeastern croatia. poje (1982, 1985, 1986) focused on the molluscan fauna from loess-palaeosol sequences at the vukovar and đakovo loess plateaus, south of baranja. bronger (1976, 2003) correlated loess-palaeosol sequences in east and central asia with others in south-east central europe, which are very close to the baranja region. galović et al. (2009) focused on the chronostratigraphy of loess deposits of zmajevac on the southern slopes of the bansko brdo in baranja. from the same section molnár et al. (2010) investigated mollusc abundance from three palaeosol-related horizons. finally, wacha & frechen (2011) provided luminescence dating for middle to late pleistocene sections of vukovar, while galović et al. (2011) investigated a loess-palaeosol section in šarengrad. the aim of this study is the reconstruction of climate changes during the latest middle and late pleistocene based on the mollusc composition of different loess horizons of the zmajevac pls. this data will be integrated with magnetic susceptibility measurements, grain size analyses, mineral figure 1: map showing the geographic position of the baranja region in cro atia and investigated loess profile at the zmajevac locality, bansko brdo (shown by the star mark). the locality previously investigated by galović et al. (2009) is indicated by the square. geology is from croatian geological survey (2009): 1. miocene andesite and rhyo lite, 2. b a denian (middle miocene) limestone and marl with igneous clas tics, 3. pleistoc ene fluvial sediments, 4. pleistocene loess (a) and loess-like sediments (b), 6. holocene marshy sediments, 7b. holo cene pro luvial sediments. banak et al.: late pleistocene climate history of the baranja loess plateau – evidence from the zmajevac loess-paleosol section (northeastern croatia) geologia croatica 413 abundances (modal analysis), and calcimetry to provide a better control on palaeoclimate interpretations. the infrared stimulated luminescence (irsl) data of galović et al. (2009) will be finally compared with present results and integrated into a chronological framework for the zmajevac lps whereby a correlation of its depositional units with the marine isotope stages of martinson et al. (1987) will be discussed. 2. geological setting the surface geomorphology of baranja is monotonous consisting largely of pleistocene and holocene sediments, with some minor outcrops of miocene and pliocene sedimentary and magmatic rocks (velić & vlahović, 2009) (fig. 1). tectonically it belongs to the pannonian basin, accommodating first central paratethys marine deposits during the middle miocene, then lake pannon brackish deposits in the late miocene and finally fresh water sediments of lake slavonia in the pliocene completing the subaquatic deposition (royden, 1988; piller et al., 2007; harzhauser & mandic, 2008; mandic et al., 2011). bansko brdo is the only morphological high in the area and represents part of a tectonic horst stretching 20 km in a ne-sw direction, reaching the banks of the danube river to the ne end. its elevation reaches 244 m (fig. 1). a combination of active neotectonic uplifting and danube river erosion exposed large outcrops of a pleistocene loess-palaeosol succession on bansko brdo. the hill is surrounded by a holocene fluvial, oxbow lake, and marsh deposits. the oldest exposed rocks at bansko brdo belong to the miocene volcano-sedimentary complex, and include basalt-andesite and pyroclastic rocks comprising volcanic and tuffaceous breccia and conglomerates. k-ar radiometric, whole -rock measurements indicate an early middle miocene age (13.8±0.4 and 14.5±0.4 ma, pamić & pécskay, 1996). this complex probably originated from partial melting of the heterogeneous lower crust due to continental rifting processes during pannonian basin extension (horváth, 1995, pamić, 1997; pavelić, 2001; mandic et al., 2011). the basalt-andesite intercalates middle miocene (badenian) marine calcareous sand and marl, indicating the synsedimentary character of the volcanic activity (pamić & pikija, 1987; lugović et al., 1990). furthermore few outcrops of pliocene fresh-water, coarse-grained clastic deposits occur at bansko brdo. the pleistocene loess is the most dominant deposit in the geological pattern of bansko brdo (velić & vlahović, 2009). the mean thickness of the loess-palaeosol sequence is 28 m for the outcrop section. the oldest loess at the zmajevac locality produced an infrared optically stimulated luminescence (irsl) age of 217±22 ka, while the youngest loess has an irsl age of 16.7±1.8 ka (galović et al., 2009). 3. sampling and methods section logging and sampling was carried out in 2009 and 2010. thereby the depositional units and their internal sedimentary characteristics have been described including photographic and gps documentation. data on the vertical changes of magnetic mineral content in the section was gathered from 44 samples collected into 200 ml plastic containers (kukla, 1987). magnetic susceptibility measurements were performed using a bartington ms 2 laboratory device. sample material was decanted into, 100 ml plastic containers before fixing to the measuring module with a calibrated standard. each sample was measured three times for precision. data was processed with the bartington software. in general palaeosol horizons show enhanced ms values due to increased concentrations of pedogenic ferrimagnetic minerals (geiss & zanner, 2006), while the loess units are marked by a significantly decreased signal. the variations are related to soil forming processes and reflect differences in composition, concentration, and particle size of the magnetic minerals, between interglacial/interstadial and glacial/ stadial sediments (kukla, 1987; evans & heller, 2001). therefore magnetic susceptibility may reveal patterns congruent to the specmap marine oxygen-isotope record (martinson et al., 1987), and can provide an excellent stratigraphic correlation tool (marković et al., 2008, 2009, 2011). thirteen bulk sediment samples (8–10 kg) were collected from loess and loess-like horizons for every 1.5 m of the zmajevac lps with at least one sample per defined lithostratigraphic unit. grain-size analyses combined wet sieving and the pipette method. classification of the grain size distribution follows wentworth (1922). mineral abundances (modal analyses) used the 0.063–0.125 mm calcite-free fraction. heavy and light mineral fraction (hmf and lmf) were separated in bromoform liquid (chbr3, δ=2.86 gcm–3) by gravity. qualitative and quantitative analyses of the fractions were based on 300–350 grains per sample and were conducted using a polarizing light microscope (menge & maurer, 1992). the carbonate (caco3) content was calculated from the weight difference before and after cold hydrochloric acid (5 %) treatment. mollusc shells were derived from samples by screen-washing in distilled water, using a 0.7 mm mesh sieve. as proposed by ložek (1964), beside completely preserved shells only larger fragments including apices and apertures were picked out and counted. identifications are based on comparison with collection material at natural history museum in vienna, following the taxonomic concepts of ložek (1964) and frank (2006). assemblage analysis follows ložek (1964). 4. results 4.1. description of the section the loess-palaeosol succession is situated 450 m south of the zmajevac section of galović et al. (2009) and mólnar et al. (2010). it outcrops in the vertical wall beside the road from beli manastir to batina (fig. 1). gps coordinates of the bottom point of the section are 45° 48’ 38’’ n and 18° 49’ 7’’ e. its altitude is 92 m. the 17.5-m-thick section exposess 6 loess, 1 loess-like and 4 palaeosol horizons geologia croatica 65/3geologia croatica 414 (fig. 2). the lithostratigraphically defined loess/loess-like horizons are coded from top to the base as l1 to l7, the palaeosol horizons – from p2 to p4. the third palaeosol representing the loess l3 intercalated doublet, received codes p3a and p3b. f1 marks the holocene soil. the lowermost unit of the section is the 80 cm-thick light yellowish brown loess l7. in the upper part of the unit carbonate concretions are concentrated. they attain 15–20 cm in diameter, are rounded and somewhat flattened. mollusc remains and carbonate root casts are also present. the overlying palaeosol horizon p4 is 50 cm thick and light brown to yellowish brown in colour, somewhat lighter in its basal part. l6 follows upsection represented by the 60 cm-thick, light yellowish brown loess. the unit contains relatively abundant mollusc fauna, and a small amount of fe-mn concretions and nodules 1–2 mm in diameter. the light grey to pale yellowish 240 cm-thick loess-like unit l5 follows upsection. dark brown fe-mn nodules and small concretions 1–2 mm in diameter are common. stems tentatively ascribed to a fossil reed are preserved as limonitized, pale orange to light brown tubes 5–10 cm in length and 0.5–1 cm in diameter. molluscs are rare in this unit, but several fragments of mammoth tusk (up to 30 cm x 8–10 cm in size) were discovered in its middle part. the surface of the tusks is pale brown to yellowish brown in colour, while the core is white to pale yellow. laterally, some smaller, 5–6 cm-long tusk fragments were also discovered. the next loess unit l4 is 40–50 cm thick and light yellowish in colour. it bears abundant white to pale yellowish, carbonate concretions measuring up to 10–15 cm in diameter, with variable, but mostly rounded form. mollusc remains are rare. a well developed, 180 cm thick pedocomplex follows consisting of two palaeoesol horizons (p3a and p3b) separated by a 40–50 cm-thick light, yellowish brown, loess horizon l3, with a fairly rich mollusc fauna. the top 50 cm of the upper paleosol f3a is brown to light brown, and for the lower 30 cm light brown, to yellowish brown in colour. f3b is brownish in its upper 40 cm and light brown to yellowish brown in its lower 40 cm. the next horizon l2 is composed of 480 cm light yellowish loess, rich in molluscs underlain by 50 cm horizontally laminated sand, which is fine-grained and light yellow in colour. the stratification is represented by laminae-separated into 1–3 cm-thick sediment packages. l2 is overlain by a 60 cm thick, weakly developed, olive brown to yellowish brown palaeosol horizon p2, with no mollusc remains. finally, the uppermost 450 cm-thick unit l1 is composed by light yellowish brown silty loess. this unit is rich in mollusc fauna and bears carbonate filled tubes of fossilized root remains. 4.2. grain-size, carbonate content and mineral distribution grain-size analyses indicate silt as the dominant grain-size fraction in all 13 studied loess samples (fig. 3). of these, seven (mostly from loess horizons l1 and l2) contain small amounts of clay-sized minerals. the abundance of sandsized particles ranges from 5.5% to 15%. the laminated unit in the base of l2 is composed of 81% sand, 11% silt and 8% clay, with a median grain-size of 0.22 mm. the four lowermost loess samples indicate a higher percentage of coarse silt and sand-sized particles in reference to all loess samples. median grain-size is largely constant between 0.025–0.03 mm, with exception for 4 lowermost samples showing significant increase, with the peak in l5 horizon (72% large coarse-silt and sand-sized fraction). skewness is fairly constant in all 13 samples, averaging of 0.78. sorting is dominantly poor, with an average value around 1.5. caco3 content of the samples ranges between 2.9% and 23.3% (fig. 3), with an average value of 9.3%. the highest figure 2: lithology of the investigated loess-palaeosol succession at zmajevac (45° 48’ 38’’ n, 18° 49’ 7’’ e). banak et al.: late pleistocene climate history of the baranja loess plateau – evidence from the zmajevac loess-paleosol section (northeastern croatia) geologia croatica 415 figure 3: sedimentological data and caco3 content from 13 bulk samples documenting facies changes of loess and loesslike horizons. please note that palaeosol horizons have not been sampled. table 1: mineral assemblage from loess samples. op – opaque minerals, do – dolomite, bi – biotite, ch – chlorite, thm – transparent heavy minerals, tu – tourmaline, zr – zirconium, ru – rutile, am – amphibole, py – pyroxene, ep – epidote, ga – garnet, cy – cyanite, st – staurolite, tit – titanite, czt – clinocoisite, cto – chloritoide, csp – cromespinel, si – silimanite, x – undetermined, q – quartz, f – feldspar, rf – rock fragments, mu – muscovite sa m pl e heavy mineral fraction (%) light mineral fraction (%) (%) op do bi eh thm transparent heavy minerals tu zr ru ap am py ep ga cy st tit czt eto csp si x p f rf m 13 9.83 15 2 83 2 + 1 26 1 30 28 1 5 1 2 + 2 50 32 13 5 12 8.88 12 + 7 81 4 1 3 39 24 19 + 3 1 3 + 1 54 16 22 6 11 8.18 12 10 78 3 1 1 31 27 22 1 6 2 3 + 2 67 20 9 4 10 6.76 14 6 82 1 1 1 + 29 32 21 2 6 2 2 2 61 23 11 5 9 11.11 12 4 + 4 79 3 1 2 1 24 2 23 27 2 7 3 3 2 59 27 22 2 8 6.14 13 6 81 3 + 3 26 + 26 24 1 5 3 + 2 54 19 20 7 7 5.31 13 6 81 2 2 32 + 28 22 5 6 + 1 + 2 60 18 19 3 6 10.1 11 14 75 2 + + 35 + 26 23 4 4 + 2 + + 2 56 15 23 6 5 4.15 20 + 3 76 1 2 2 18 2 23 38 1 8 2 + 2 50 25 18 7 4 11.21 14 1 85 3 2 1 2 23 1 29 25 1 6 1 3 + 1 63 21 14 2 3 11.4 11 + 88 4 + + 1 27 29 22 1 10 + 2 2 68 10 20 2 2 6.85 13 3 83 1 + 4 + 31 29 25 1 5 + 1 + 1 62 17 15 7 1 6.54 26 1 73 3 2 3 12 22 41 3 11 1 1 55 28 16 1 geologia croatica 65/3geologia croatica 416 value is measured in the base of the uppermost l1 loess horizon, while the lowest (2.9%) was measured in the l4 loess horizon, bellow the f3b palaeosol. the caco3 content is in accordance with typical values for loess deposits, with the exception of 23.3% in the upper part of the l2 loess unit. modal analysis pointed out that the light mineral fraction (lmf) is dominant in all samples, whereas the heavy mineral fraction (hmf) range, from 4.15% to 11.21% (table 1). quartz is the dominant lmf mineral ranging between 50% and 74% (mean = 59.5%). the feldspar group is the second most abundant ranging between 6% and 32% (mean = 17.1%). the rock particle content is between 9% and 24% (mean = 16.7%). muscovite is present in all the analysed samples ranging from 1% to 21% (mean = 7.1%). in the hmf, the transparent heavy minerals (thm) are more common than opaque ones, whilst chlorite and dolomite are rare. the most common thm are the mineral groups of epidote, garnet and amphibole. the epidote group is most abundant and ranges from 17% to 37% (mean = 27.5%), garnet group ranges from 16% to 61% (mean = 26.5%), amphibole group from 1% to 35% (mean = 26.1%). chlorite is present in all samples ranging from 1% to 14% (mean = 4.92%), with mean in l1, l2, and l3 distinctly higher (6.44%), than in l4, l5, l6 and l7 (1.5%). 4.3. magnetic susceptibility magnetic susceptibility (ms) values from loess and loesslike sediment range from 5 to 28.5 x 10–6 si (fig. 6). l1 horizon from the upper part of the section ranges from 15 to 20 x 10–6 si. the uppermost palaeosol horizon (f2) shows the figure 4: species occurring in studied samples of the zmajevac section. scale bar is 2 mm. 1. helicopsis hungarica (soós & wagner, 1935). 2. vallonia tenuilabris (a. braun, 1843). 3. vitrea contracta (westerlund, 1871). 4. helicopsis striata (o.f. müller, 1774). 5. arianta arbustorum (linnaeus, 1758). 6. clausilia (andrea) dubia draparnaud, 1805. 7. chondrula tridens (o.f. müller, 1774). 8. cochlicopa lubrica (o.f. müller, 1774). 9. succinea oblonga (draparnaud, 1801). 10. orcula dolium (draparnaud, 1801). 11 pupilla muscorum (linnaeus, 1758) 12. pupilla loessica (ložek, 1954). 13. columella columella (martens, 1830). banak et al.: late pleistocene climate history of the baranja loess plateau – evidence from the zmajevac loess-paleosol section (northeastern croatia) geologia croatica 417 highest measured values within the section (82.5 x 10–6 si). values in the loess unit l2 are again much lower, with a mean of 14 x 10–6 si. a notable peak within this horizon is 28.5 x 10–6 si. the pedo-complex constituents p3a and p3b are marked by significant peaks that are however lower than in the f2 horizon. upper palaeosol f3a attains 67.7 x 10–6 si, the underlying p3b 53.2 x 10–6 si. the lowermost palaeosol p4 shows again a somewhat higher ms of 58.3 x 10–6 si. 4.4. mollusc palaeontology a total of 1705 terrestrial gastropod specimens classified to 13 species (tab. 2 and fig. 4) were obtained from 13 samples. specimen richness, related to mollusc density within the samples varies upsection (fig. 5). hence, the mollusc densities are moderate in horizons l7 (85) and l6 (117), strongly decreased in l5 (5) and l4 (7), and strongly increased in l3 (90), l2 (213), and l1 (136). helicopsis striata, h. hungarica and arianta arbustorum are present in all horizons (fig. 5), except for l4 and l5. columella columella is rare in all horizons showing peak abundance in l2 (3.29%, and 4.44%). the mean abundance of pupilla muscorum and p. loessica is 11.34% with the highest abundance of 14.6% in l2. the latter horizon also produced the greatest number of individuals, representing all 13 species identified in the section. 5. discussion 5.1. sedimentary facies and provenance of loess the grain-size distribution is in good accordance with other loess localities in the pannonian basin (galović et al., 2009; bokhorst et al., 2011). the studied locality shows the predominance of fine and medium silt in loess. three lowermost loess units (l7, l6, l5) display an increase in the median grain-size, and coarse silt and sand exceed 50 %. the horizontally stratified fine-grained sand in the base of the l2 unit may be compared with aeolian sands with plane bed lamination (hunter, 1977) and are probably wind ripple deposits (hunter, 1977; clemmensen & abrahamsen, 1983). thamó-bozsó & kovács (2007) published valuable data about the heavy mineral composition of flood plain sediments of the palaeo-danube and tisza. the garnet and epidote mineral groups, amphiboles and chlorite are the most abundant heavy minerals in samples collected near the danube river. the river tisza and its tributaries drain abundant volcanic rocks, contrasting with those of the largely metamorphic and granitoid complex of the danube. comparing heavy mineral assemblage from zmajevac lps, with that data, it is obvious, that the main source area for loess in baranja is from the danube flood plain sediments. the main transport direction was from the north or north-west. nevertheless, the higher concentration of amphiboles in the zmajevac lps (if compared with those from the danube plain in central hungary), suggests an additional source area. the western carpathians with neogene calc-alkaline volcanic rocks is the major source for amphiboles (thamó-bozsó & kovács, 2007). the percentage of amphiboles in the hmf of the zmajevac lps is fairly constant, averaging 28.8% in the three uppermost loess horizons and 23.25% in the lowermost four. alternatively those minerals could also be denudation products from locally exposed volcanic and metamorphic rocks of the southward neighboring slavonian mts. (jamičić et al., 1987). mt. krndija and mt. papuk, which are the closest to baranja of all the slavonian mts., consist of amphibolites. furthermore, pliocene sands from the northern slopes of mt. krndija and mt. papuk are of local origin and contain abundant amphiboles (jamičić et al., 1987). table 2: palaeoecological ranges of recorded mollusc species after krolopp & sümegi (1995) and sümegi & krolopp (2002). c – cryophilous, h – hygrophilous, t – thermophilous, m – mesophilous, w – woodland preference, cr – cold resistant, sh – subhygrophilous, o – open habitat preference, w/o – intermediate habitat, d – aridity tolerant. species paleoclimate group paleohumidity group paleovegetation group biogeographical group helicopsis striata (o.f. muller, 1774) t d 0 central european helicopsis hungarica (soos & vvagner, 1935) t d 0 central and se european chondrula tridens (o.f. muller 1774) t d 0 central and se european vallonia tenuilabris (a. braun, 1843) c d 0 n and central asian arianta arbustorum (linnaeus, 1758) cr h w w and central european pupilla muscorum (linnaeus, 1758) m m 0 holarctic pupilla loessica (ložek, 1954) c d 0 extinct orcula dolium (draparnaud, 1801) m h w central european succineaoblonga (draparnaud, 1801) cr h 0 eurosiberian columella columella (martens, 1830) c h 0 boreo-alpine clausilia dubia (draparnaud, 1805) m sh w central european vitrea contracta (vvesterlund, 1871) m sh w/o european cochlicopa lubrica (o.f. muller, 1774) m m w/o holarctic geologia croatica 65/3geologia croatica 418 5.2. palaeoclimate, palaeohumidity and palaeovegetation the identified mollusc species have been classified according to their palaeoenvironmental preferences following krolopp & sümegi (1995) and sümegi & krolopp (2002) (tab. 2). the presence and abundance of each species in the sample is considered thereby as a function of available palaeoclimate and palaeohumidity conditions and/or type of palaeovegetation (fig. 5). thermophilous and mesophilous species are dominant in terms of paleotemperature (74–55% abundance, fig. 5), although none of the warm-climate representatives, typical for interglacial periods, such as helicigona banatica, mastus bielzi or discus perspectivus have been observed. nevertheless, compared to the holocene, detected species compositions suggest unfavourable regional climate conditions during loess deposition in the late pleistocene. thereby arid climate species are common in all horizons with a mean abundance of 50.49%. finally open habitat representatives likely dominate the section with mean abundance of 66.81% and peak in l5 loess horizon (71.4%). the species distribution shows similarities with the irig section on the southern slope of fruška gora in nw serbia (marković et al., 2007). the lowermost palaeosol of the zmajevac section can be compared with palaeosol horizon v-s1 in irig, which is barren of terrestrial molluscs representing the last interglacial (mis5) climate phase. in the zmajevac section, corresponding loess horizon may be represented by fossil poor samples 3 and 4. above this, in both the irig and zmajevac sections the dominant helicopsis striata fauna reflects the late pleistocene central european “warm” loess environmental conditions described by ložek (1964). in contrast, the lowermost samples in both sections bear common cooler climate representatives such as clausilia dubia reflecting the middle pleistocene penultimate glacial (mis6) conditions. the late pleistocene assemblages from petrovaradin show, in contrast, colder and more humid conditions than in either irig or zmajevac, probably due to the palaeogeographic position at the northern slope of fruška gora (marković et al., 2005, 2008). in adition to the irig locality, the zmajevac section also represents the more sun-exposed southeastern side of banovo brdo. 5.3. mollusc assemblage analysis species compositions of the samples reveal the presence of five glacial type assemblages defined in ložek (1964), including chondrula tridens, helicopsis striata, pupilla loessica, columella collumella and arianta arbustorum. therefore, of the six originally introduced assemblage types only those with bradybaena fruticum marking the warmest glacial episodes (ložek, 1964) have not been found in the studied samples of the zmajevac lps (fig. 6). horizon l7 displays a columella columella assemblage with depleted nominal species but with a high percentage of concurrent orcula dolium (27.05%) and clausilia dubia figure 5: the individual abundances of 13 mollusc species from zmajevac lps samples. palaeoenvironmental proxy curves result from abundance data for the palaeoecological categories presented in table 2. banak et al.: late pleistocene climate history of the baranja loess plateau – evidence from the zmajevac loess-paleosol section (northeastern croatia) geologia croatica 419 (12.94%). horizon l6 displays a similar faunal composition (fig. 5). thus it is likely classified as columella columella assemblage. horizons l4 and l5 yielded few molluscs so a determination of mollusc assemblage type is highly speculative. the small number of shells obtained results from strong fragmentation of mollusc shells in that horizons. the l4 horizon is tentatively attributed to transitional helicopsis striata – arianta arbustorum assemblage, whereas l5 is defined as a helicopsis striata assemblage. the l3 horizon is marked by a transitional helicopsis striata – pupilla loessica assemblage. the position of this horizon between two palaeosols of a pedo-complex indicates abrupt cooling during a period of warm and humid climate. in this sample a significant percentage of cochlicopa lubrica was detected (12.2%), which is often a part of typical loess faunas. horizon l2 is characterized by the highest densities of mollusc remains in the section. in its lowermost part, a transitional pupilla loessica – helicopsis striata assemblage with almost equal number of pupilla sp. and helicopsis sp. indifigure 6: correlation of the studied section with marine isotope stages (modified after martinson et al., 1987 and aitken & stokes, 1997) and zmajevac section of galović et al. (2009) and mólnár et al. (2010). the irsl age estimates are by the mollusc paleotemperature inference by mólnár et al. (2010). palaeosol positions are indicated in the lithological columns by dark gray colour. loess (white) and loess-like (light gray) horizons are numbered in their order of appearance (from top to base). the lithological columns have the same scale. geologia croatica 65/3geologia croatica 420 viduals is present. a helicopsis striata – pupilla loessica assemblage follows above. the middle part of the horizon produced a helicopsis striata assemblage with common vallonia tenuilabris (6.59%). finally the uppermost part bears a transitional arianta arbustorum – chondrula tridens assemblage. the l1 horizon is characterized by common representatives of a helicopsis striata assemblage commonly developed as transitional assemblage types. a sample from the base of l1 contains a typical helicopsis striata assemblage, followed by the transitional helicopsis striata – columella columella assemblage. above, a helicopsis striata – pupilla loessica assemblage was detected. along with pupilla sp., vallonia tenuilabris is also abundant (11%). finally the uppermost part of horizon l1 belongs to the transitional helicopsis striata – chondrula tridens assemblage. a helicopsis striata assemblage is dominant throughout the lps zmajevac, with transition to colder and warmer climate conditions, as recorded by the pupilla loessica – columella columella and arianta arbustorum – chondrula tridens assemblages. the helicopsis striata assemblage indicates climate conditions preceding the last glacial/stadial maximum. chondrula tridens and arianta arbustorum are generally abundant species, but their abundance is never high enough for definition of a chondrula tridens or arianta arbustorum assemblage. actually these were defined through abundance of typical concurrent species as defined by ložek (1964). both assemblages mark slightly humid steppe conditions, whereas, the first one is bounded by phases of chernozem formation. the pupilla loessica and columella columella assemblages are typical loess faunas and exponents of glacial/stadial maximum. arid and cold climate conditions are indicated by the pupilla loessica assemblage, more humid conditions by the presence of the columella columella assemblage. pupilla muscorum, helicopsis striata, vallonia tenuilabris and succinella oblonga are concurrent species in pupilla loessica assemblages, while orcula dolium, clausilia dubia and arianta arbustorum alpicola are additional species in a columella columella assemblage. interestingly the best known ne croatian terrestrial mollusc assemblage (poje, 1984) from the well dated (wacha & frechen, 2011) section of vukovar reflects a similar cold spell around the mis 5 lower boundary. yet, the recorded assemblages seem to reflect somewhat more arid microclimate conditions. 5.4. stratigraphic correlation and palaeoclimate history based on irsl age estimate of 20.2±2.1 ka, galović et al. (2009) correlated the uppermost part of the loess-palaeosol succession at zmajevac with the upper pleniglacial mis 2. the base of the succession represented by a loess horizon yielded an irsl age estimate of 217±22 ka and was tentatively correlated with the middle pleistocene mis 8. however the lowermost 6 m of the zmajevac succession are not exposed in the present outcrop (fig. 6) that starts with the loess unit l7. the latter unit yielded the irsl age estimate of 121±12 ka and was tentatively correlated with the penultimate glacial mis 6 by galović et al. (2009). the loess horizon l7 is overlain by palaeosol p4 and followed immediately by the next loess unit (l6). those two lowermost loess horizons (l6 and l7) are characterized by the presence of a columella columella assemblage (fig. 6). its equivalent is a pupilla loessica assemblage indicated in horizons l3 and l2 and likely a typical loess fauna representing however more arid climate conditions. in contrast, the columella columella assemblage is an indicator of the glacial maximum (ložek, 1964), with dominantly humid climate conditions. compared with malacofaunal results from irig and ruma lps in vojvodina (marković et al., 2006, 2007), that fauna represents palaeoenvironment of open grassland, and a cold, wet climate. hence the presence of a columella columella assemblage in the basal part of the section strongly supports its correlation with the mis 6 stage proposed by galović et al. (2009). sedimentological and magnetic susceptibility (ms) data obtained from zmajevac lps show similarities with other loess-palaeosol sequences in the pannonian basin investigated recently (marković et al., 2006, 2007; galović et al., 2009; molnár et al., 2010; wacha & frechen, 2011). ms values are in the expected range, especially in loess horizons. ms values from four palaeosols are comparable with those from irig in neighboring vojvodina (marković et al., 2007). the lowermost p4 palaeosol, displays significantly weaker signals, than the p2 palaeosol, but stronger than the overlying p3b palaeosol horizon (fig. 6). the ms value of 58.3 x 10–6 si in the p4 palaeosol is lower than expected for an interglacial period and a fully developed soil. even though it is the oldest palaeosol, a weaker signal than in the youngest f2 may indicate that iron is present in oxidized form in limonitic minerals. it is most likely that the low ms values result from mineral leaching. such a decrease in the ms signal in clayey horizons was also detected in germany by rousseau et al. (2002) and in hungary by novothny et al. (2009). it is very likely that similar processes affected the p4 palaeosol horizon in zmajevac. in agreement with data by galović et al. (2009) the p4 horizon is correlated with the mis 5e interglacial period. the pedo-complex forming palaeosol horizons p3a and p3b is similar to a pedo-complex from the vojvodina (marković et al., 2007) and hungary. reminiscent of synchronous horizon of hungarian sütto lps (novothny et al., 2011), the signal from the p3 pedo-comlex is higher than the one measured in vojvodina. finally, the strongly increased ms value of 82.5 x 10–6 si suggests that the uppermost palaeosol p2 represents an interglacial, rather than an interstadial phase. the chronostratigraphic data obtained by galović et al. (2009) imply the straight forward correlation of this horizon with the mis 3 stage (fig. 6). the integration of palaeontological results with irsl age estimates fixed the correlation of loess l7 with mis 6. through correlation of loess l2 with the lower pleniglacial mis 4, (based likely on integrated palaeontological and chronostratigraphical data (galović et al., 2009)), the interchanging facies character between units l7 and l2 sugbanak et al.: late pleistocene climate history of the baranja loess plateau – evidence from the zmajevac loess-paleosol section (northeastern croatia) geologia croatica 421 gests climate forcing reflecting the five-folded pattern of mis 5 (fig. 6). the loess-like horizon l5 could thereby correlate with the warmer mis 5c, while l6 and l4 loess units would correspond to mis 5d and mis 5b cooling events, respectively. if this correlation proves true the whole studied succession, except for the lowermost loess l7 would have been deposited during the late pleistocene (fig. 6). 6. conclusion the present investigation of the zmajevac loess-palaeosol sequence (lps) established valuable palaeontological data for palaeoclimate and palaeoenvironmental reconstruction of baranja during the latest middle and late pleistocene. the recorded mollusc compositions display small but important differences to other pannonian basin lpss, especially for horizons l7, l6 and l3. hence the later assemblages indicate still cooler and more humid climate conditions than previously known (poje, 1984). this difference is probably a consequence of local geomorphology and microclimate conditions. indeed the mollusc fauna from the rest of the samples is in very good agreement with the previous pannonian basin record. additional data obtained from sedimentological and magnetic susceptibility analyses, seem to show fairly good congruence with results from other lps in the pannonian basin (marković et al., 2006, 2007; novo thny et al., 2011; wacha & frechen, 2011), although low sampling frequency prevent their use for more comprehensive correlation. acknowledgement thanks go to mathias harzhauser (nhm vienna) for discussion on gastropod taxonomy, anita eschner (nhm vienna) for providing access to malacologicial collection of the zoological department and alice schumacher (nhm wien) for providing gastropod photographic documentation. we are also grateful to reviewers manfred frechen and slobodan b. marković for their constructive criticism and valuable improvements of the manuscript. this paper was supported by projects no. 181-181-1096-1093, 195-1951293-2703 and 195-1951293-0237 of the ministry of science, education and sports of the republic of croatia. references aitken, m. j. & s. stokes (1997): climatostratigraphy.– in: taylor, r.e. & aitken, m.j. (eds.): chronometric dating in archaeology. advances in archaeological and museum science series, vol. 2, plenum, new york. bačani, a., šparica, m. & velić, j. (1999): quaternary deposits as the hydrogeological system of eastern slavonia.– geol. croat., 52, 141–152. bognar, a. (1976): les i lesu slični sedimenti i njihovo geografsko značenje [loess and loess like deposits and their geographical meaning – in croatian].– geogr. horizont, 1–2, 15–31. bokhorst, m.p., vandenberghe, j., sümegi, p., lanczont, m., gerasimenko, n.p., matviishina, z.n., marković, s.b., frechen, m. (2011): atmospheric circulation patterns in central and eastern europe during the weichselian pleniglacial inferred from loess grain-size records.– quat. int., 234, 62–74. doi: 10.1016/ j.quaint.2010.07.018 bronger, a. (1976): zur quartären klima und landschaftsentwicklung des karpatenbeckens auf (paläo-) pedologischer und bodengeographischer grundlage.– kieler geographische schriften, 45, 1–268, kiel. bronger, a. (2003): correlation of loess–palaeosol sequences in east and central asia with se central europe: towards a continental quaternary pedostratigraphy and paleoclimatic history.– quat. int., 106/107, 11–31. clemmensen, l.b. & abrahamsen, k. (1983): aeolian stratification and facies association in desert sediments, arran basin (permian), scotland.– sedimentology, 30, 311–339. croatian geological survey (2009): geološka karta republike hrvatske 1:300.000 [geological map of the republic of croatia 1:300 000 – in croatian].– zagreb. evans, m.e. & heller, f. (2001): magnetism of loess/palaeosol sequences: recent developments.– earth sci. rev., 54, 129–144. frank, c. (2006): plio-pleistozäne und holozäne molluscen österreichs.– verlag der österreichischen akademie der wissenschaften, wien, 1–797. galović, l., frechen, m., halamić, j., durn, g & romić, m. (2009): loess chronostratigraphy in eastern croatia – a luminescence approach.– quat. int., 198, 85–97. doi: 10.1016/j.quaint. 2008.02.004 galović, l., frechen, m., peh, z., durn, g. & halamić, j. (2011): loess/palaeosol section in šarengrad, croatia – a qualitative discussion on the correlation of the geochemical and magnetic susceptibility data.– quat. int., 240, 22–34. doi: 10.1016/j.quaint. 2011.02.003 geiss, ch. e. & zanner, c.w. (2006): how abundant is pedogenic magnetite? abundance and grain size estimates for loessic soils based on rock magnetic analyses.– j. geoph. res., 111, b12s21. doi: 10.1029/2006jb004564 guo, z.t., rudiman, w.f., hao, q.z., wu, h.b., qiao, y.s., zhu, r.x., peng, s.z., wei, j.j., yuan, b.y. & liu, t.s. (2002): onset of asian desertification by 22 myr ago inferred from loess deposits in china.– nature, 416, 159–163. harzhauser, m. & mandic, o. (2008): neogene lake systems of central and south-eastern europe: faunal diversity, gradients and interrelations.– palaeogeogr. palaeocl. palaeoec., 260, 417–434. doi: 10.1016/j.palaeo.2007.12.013 horváth, f. (1995): phases of compression during the evolution of the pannonian basin and its bearing on hydrocarbon exploration.– mar. petrol. geol., 12, 837–844. hunter, r.e. (1977): basic types of stratification in small eolian dunes.– sedimentology, 24, 361–387. jamičić, d., brkić, m., crnko, j. & vragović, m. (1987): osnovna geološka karta sfrj 1:100000. tumač za list orahovica l33–96 [basic geological map of sfry 1:100000, geology of the orahovica sheet – in croatian].– inst. za geol. istraž., zagreb, sav. geol. zavod, beograd, 1–72. kovács, j. (2008): grain-size analysis of the neogene red clay formation in the pannonian basin.– int. j. earth. sci., 97, 171–178. krolopp, e. & sümegi, p. (1995): palaeoecological reconstruction of the late pleistocene, based on loess malacofauna in hungary.– geojournal, 36, 213–222. kukla, g.j. (1987): loess stratigraphy in central china.– quat. sci. rev., 6, 191–219. ložek, v. (1964): quartärmolluscen der tschechoslowakei.– rozpr. ust. geol., 31, 1–374. lugović, b., majer, v. & strumpfl, w.e. (1990): geochemical characteristics of basaltic andesites from baranja (croatia, yugoslavia).– geol. vjesnik, 43, 135–142. geologia croatica 65/3geologia croatica 422 malez, m. (1965): o nekim periglacijalnim pojavama u pleistocenu slavonije [on some periglacial occurrances in the pleistocene of slavonia-in croatian].– geol. vjesnik, 18, 159–165. mandic, o., de leeuw, a., bulić, j., kuiper, k., krijgsman, w., jurišić-polšak, z. (2011): paleogegraphic evolution of the southern pannonian basin: 40ar/39ar age constrains on the miocene continental series of northern croatia.– int. j. earth. sci., 101, 1033–1046. doi: 10, 1007/s00531-011-0695-6. marković, s.b., mccoy, w.d., oches, e.a., savić, s., gaudenyi, t., jovanović, m., stevens, t., walther, r., ivanišević, p. & galić, z. (2005): palaeoclimate record in the upper pleistocene loess-palaeosol sequence at petrovaradin brickyard (vojvodina, serbia).– geol. carpath. 56, 545–552. marković, s.b., oches, e., sümegi, p., jovanović, m. & gaudenyi, t. (2006): an introduction to the middle and upper pleistocene loess-palosol sequence at ruma brickyard, vojvodina, serbia.– quat. int., 149, 80–86. doi: 10.1016/j.quaint.2005.11.020 marković, s.b., oches, e.a., mccoy, w.d., gaudenyi, t., frechen, m., jovanović, m. (2007): malacological and sedimentological evidence for ‘warm’ climate from the irig loess sequence (vojvodina,serbia).– geophysics, geochemistry and geosystems 8, q 09008. doi: 10.1029/2006gc001565 marković, s.b., bokhorst, m.p., vandenberghe, j., mccoy, w.d., oches, e.a., hambach, u., gaudenyi, t., jovanović, m., zöller, l., stevens, t. & machalett, b. (2008): late pleistocene loess-palaeosol sequences in the vojvodina region, north serbia.– j. quat. sci., 23, 73–84. doi: 10.1002/ jqs.1124 marković, s.b., hambach, u., catto, n., jovanović, m., buggle, b., machalett, b., zöller, l.,glaser, b. & frechen, m. (2009): middle and late pleistocene loess sequences at batajnica, vojvodina, serbia.– quat. int., 198, 255–266. doi: 10.1016/j.quaint.2008.09.003 marković, s.b., hambach, u., stevens, t., kukla, g.j., heller, f., mccoy, w.d., oches, e.a., buggle, b., zöller, l. (2011): the last million years recorded at the stari slankamen (northern serbia) loess-palaeosol sequence: revised chronostratigraphy and long-term environmental trends.– quat. sci. rev., 30, 1142–1154. martinson, d., pisias, m.g., hays, j.d., imbrie, j., moore, t.c. & shackleton, m.j. (1987): age dating and the orbital theory of ice ages: development of a high-resolution 0 to 300 000-year chronostratigraphy.– quat. res., 27, 1–30. menge, m.a. & maurer, h.f.w. (1992): heavy minerals in colour.– chapman and hall, london, 151 p. molnár, d., hupuczi, j., galović, l. & sümegi, p. (2010): preliminary malacological investigation on the loess profile at zmajevac, croatia.– cent. eur. j. geosci., 2, 52–56. doi: 10.2478/v10085 009-0045-0 novothny, á., frechen, m., horváth, e., bradak, b., oches, e.a., mccoy, w.d. & stevens, t. (2009): the loess profile at süttő, hungary.– quat. int., 198, 62–76. doi: 10.1016/j. quaint.2008.01.009 novothny, á., frechen, m., horváth, e., wacha, l. & rolf, c. (2011): investigating the penultimate and last glacial cycles of the süttő loess section (hungary) using luminescence dating, high-resolution grain size, and magnetic susceptibility data. – quat. int., 234, 75–85. doi: 10.1016/j.quaint.2010.08.002 pamić, j. (1997): vulkanske stijene savsko-dravskog međurječja i baranje (hrvatska) [volcanic rocks between sava and drava rivers – in croatian].– nafta monograph., zagreb, 192 p. pamić. j. & pécskay, z. (1996): geological and k-ar ages of tertiary volcanic formations from the southern part of the pannonian basin in croatia – based on surface and subsurface data.– nafta, 6, 195–202. pamić, j. & pikija, m. (1987): badenian andesites and pyroclastics from baranja in northern croatia (yugoslavia).– acta geol. hung., 30/1–2, 111–132. pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.– basin research, 13, 359–376. pécsi, m. (1968): loess.– in: fairbridge, r.w. (ed.): the encyclopedia of geomorphology. reinhold, new york, 674–678. piller, w.e., harzahauser, m. & mandic, o. (2007): miocene central paratethys stratigraphy – current status and future directions.– stratigraphy, 4, 151–168. poje, m. (1982): malakofauna prapornih naslaga istočnog dijela slavonije (malacofauna from loess deposits from eastern croatia – in croatian).– unpublished msc thesis, university of zagreb, zagreb, 63 p. poje, m. (1985): praporne naslage “vukovarskog profila” i njihova stratigrafska pripadnost [loess deposits from ‘’the vukovar profile’’ and their stratigraphic position – in croatian].– geol. vjesnik, 38, 45–66. poje, m. (1986): ekološke promjene na vukovarskom prapornom ravnjaku proteklih cca 500.000 godina [ecological changes on the vukovar loess plateau in last 500,000 years – in croatian].– geol. vjesnik, 39, 19–42. pye, k. (1995): the nature, origin and accumulation of loess.– quat. sci. rev., 14, 653–667. rousseau, d.d., antoine, p., hatte, c., lang, a., zöller, l., fontugne, m., othman, d.b., luck, j.m., moine, o., labonne, m., bentaleb, i., jolly, d. (2002): abrupt millennial climatic changes from nussloch (germany) upper weichselian eolian records during last glaciation.– quat. sci. rev., 21, 1577–1582. royden, l.h. (1988): late cenozoic tectonics of the pannonian basin system.– in royden, l.h. & horvath, f. (eds.): the pannonian basin. a study in basin evolution.– am. assoc. petrol. geol. mem., 45, 27–48. rukavina, d. (1983): o stratigrafiji gornjeg pleistocena s osvrtom na topla razdoblja i njihov odraz u naslagama na području jugoslavije [on stratigraphy of the late pleistocene with review of warm periods and their reflection in the area of yugoslavia – in croatian].– rad jazu, 19, 199–221. smalley i.j, marković, s.b & svirčev, z. (2011): loess is (almost totally formed by) the accumulation of dust.– quat. int., 240, 4–11. doi: 10.1016/j.quaint.2010.07.011 sümegi, p. & krolopp, e. (2002): quatermalacological analysis for modeling of the upper weichselian palaeoenvironmental changes in the carpathian basin.– quat. int., 91, 53–63. thamó-bozsó, e. & kovács, l. (2007): evolution of quaternary modern fluvial network in the mid-hungarian plain, indicated by heavy mineral distributions and statistical analysis of heavy mineral data.– dev. sedimen., 58, 491–514. wacha, l. & frechen, m. (2011): the chronology of the “gor janović loess section” in vukovar, croatia.– quat. int., 240, 87–99. doi: 10.1016/j.quaint.2011.04.010 wentworth, c.k. (1922): a scale of grade and class terms for clastic sediments.– the j. geol., 30, 377–392. manuscript received february 03, 2012 revised manuscript accepted july 20, 2012 available online october 30, 2012 geo.cro.2-3-61-kb.pdf 215 � seyed abolfazl hosseini1 and marc a. conrad2 ab stra ct palaeontological, environmental and sequence stratigraphic studies were carried out on the shallow carbonate platform facies of the berriasian to hauterivian fahliyan formation and the lower part of the gadvan formation, at kuh-e-surmeh. the studies were based on calcareous green algae (mainly dasycladales) and accompanying benthic foraminifera, focusing on revision of the considerable, pioneering work of gollestaneh (1965, 1979), initially undertaken on behalf of the national iranian oil company (nioc). thirty two species of calcareous green algae and thirty four species of benthic foraminifera were identifi ed from the fahliyan formation and from the lower part of the gadvan formation. a number of the recognized calcareous green algae were previously given different names by other authors working in sw iran. additional taxa were also recorded for the fi rst time in the zagros basin, including clypeina dragastani, c. estevezii, c. solkani, c. parasolkani, holosporella arabica, otternstella lemmensis, salpingoporella circassa, s. istriana and s. katzeri. salpingoporella circassa is quite common and apparently recorded for the fi rst time from southern tethys. also salpingoporella? inopinata n. sp., (originally named iranella inopinata by gollestaneh, a nomen nudum) appears to be quite common in the fahliyan formation, although apparently endemic to sw iran. three main depositional environments were recognized based on the faunal/fl oral association, lithological and sedimentological characteristics: inner ramp/restricted platform, mid ramp/margin to open platform, and outer ramp/platform slope, with water depths ranging from about 5m to 20m, rarely reaching 40m. facies changes facilitated the recognition of three large scale sequences throughout the studied succession, bringing interesting relationships with the sequence bundles identifi ed in the arabian plate. keywor ds: iran, zagros mountains, fahliyan formation, gadvan formation, dasycladales, foraminifers, cretaceous, stratigraphy 1 exploration directorate of national iranian oil company (nioc), p.o.box 19395 6669, tehran, iran; (seidgeo@gmail.com) 2 71 chemin de planta, 1223 cologny, switzerland; (conrad@safemail.ch) calcareous algae, foraminifera and sequence stratigraphy of the fahliyan formation at kuh-e-surmeh (zagros basin, sw of iran) geologia croatica 61/2–3 215–237 4 figs. 7 pls. zagreb 2008 geologia croaticageologia croatica � 1. introduction this paper deals with the calcareous green algae (mainly dasycladales) and foraminifera from the zagros basin (sw of iran) which aims as a tool to recognize the depositional environments and to contribute to the understanding of algal palaeoecology. the section studied is located at 52° 34’ longitude and 28° 32’ latitude, in kuh-e-surmeh, south of the town of firouzabad (fig. 1). the exposed section is 212m thick and a total number of 254 thin-sections were prepared from the collected samples. systematic description of the whole microfossil assemblages is beyond the scope of this paper which focuses on sequence stratigraphy, benthic foraminifera and the newly identifi ed dasycladalean algae. the fahliyan formation has already been documented in previous articles and in several unpublished internal reports of the national iranian oil company (nioc), dealing with biostratigraphy and facies analysis. a preliminary report on this formation was carried out by ali gollestaneh in 1965 geologia croatica geologia croatica 61/2–3 216 2. taxonomic description among many known dasycladalean algae, the fahliyan formation yielded a new species, herein tentatively assigned to the genus salpingoporella pia. the species was fi rst described and properly illustrated by gollestaneh (1965), in his unpublished phd thesis, under the name of iranella inopinata gen. and sp. nov. yet, adequately combining new observations on the present material with illustrations provided by gollestaneh remains a diffi cult task. hypothetically, more than one species may be present and certainly, additional material must be identifi ed and investigated. nevertheless, this opportunity is taken to formally introduce and provisionally describe the new species dedicated to dr. ali gollestaneh. genus: salpingoporella pia in trauth, 1918 salpingoporella? inopinata gollestaneh n. sp. (pl. 1, figs. j–m, t; pl. 2, figs. n–p; pl. 3, fig. f; pl. 4, figs. d, l–p) 1965 iranella inopinata gen. and sp. nov. – gollestaneh, p. 250, pls. 68–69 material and stratum typicum: up to 24 specimens, from different localities (kuh-e-surmeh), all from the zagros fold belt, iran. the specimen illustrated in pl. 1, fig. l is the holotype, an oblique section from sample jht 1353 in the upper, valanginian part of the section. type location is at kuhesurmeh, 50 km south of kazerun city, sw iran (fig. 1). depository: materials (rock samples and thin-sections) are housed in the department of geological and geochemical (nioc internal report no. 1056), as his phd thesis, later published in london (gollestaneh, 1965). it includes the systematic description of benthic foraminifera and calcareous green algae, along with a range chart distribution of the microfossils. therefore, the present paper is a partial revision of gollestaneh’s report, focusing on the calcareous green algae. most of the internal reports of the nioc also centre on biostratigraphy and age determination, following the zonation scheme introduced by wynd (1965) for the exploration/production agreement area. the cretaceous rock units (such as the fahliyan and gadvan formations) have been analyzed for microfossils and age determination by several geologists (gollestaneh, 1974; setudehnia, 1978; wynd, 19651; wells, 19652; kheradpir, 19753). however, additional, new, detailed palaeoecological and palaeobathymetric studies are essential for comprehension of the fahliyan formation and other lower cretaceous successions in the zagros basin, in order to ensure better correlations and improve our understanding of the regional geology. 1 wynd, j.g. (1965): biofacies of the iranian consortium-agreement area. – nioc report no. 1082, unpublished 2 wells, a.j. (1965): illustrated comments on the lithofacies/biofacies and sedimentary structures. – nioc report no. 1068, un published 3 kheradpir, a. (1975): stratigraphy of the khami group in southwest iran. – nioc report no. 1235, unpublished fi gu re 1: location map of the studied section geologia croaticaseyed abolfazl hosseini and marc a. conrad: calcareous algae, foraminifera and sequence stratigraphy of the fahliyan formation... 217 studies and researches of the exploration directorate of the national iranian oil company (nioc), a. gollestaneh’s collection. range: berriasian – valanginian, as confi rmed by foraminifera and dasycladalean algae. diagnosis: thallus and axial cavity cylindrical to slightly club-shaped. laterals horizontal, forming quincunxes, four to fi ve per verticil, connected to the main axis by a short and narrow pore (peduncle). laterals then abruptly widen out, fi rst elliptical, horizontally elongated, then circular in tangential section, where they are loosely adjacent to each other. weak imprints of cysts, whenever present, are located in the lower part of the laterals (cladospory), or at the periphery of the axial cavity (endospory). calcareous coat colourless, made of interlocking calcite crystals (originally aragonite), solid around the axial cavity, weak, forming a pellicle at the calcifi ed periphery of the laterals. dimensions: outer diameter (d) 150–507 mm inner diameter (axial cavity, d) 63–202 mm d / d 0.3–0.7 verticils spacing (h) 54– 67 mm laterals per verticil (w) 4–5 proximal width of the connecting pore 11–22 mm cysts imprint diameter approx. 40 mm comparisons and remarks: the closest species to salpingoporella? inopinata is the kimmeridgian – aptian salpingoporella hispanica conrad & grábner 1975, also with 4–5 laterals per verticil. in s. hispanica, (carras et al., 2006, pl. v, fi g. 1–5), the laterals are fi rst rectangular in section, then hexagonal, horizontally elongated. the proximal pores (peduncles) of s. hispanica are eccentrically located, laterally to the axis of the corresponding laterals. in certain sections (pl. 4, fig. p), the laterals show the presence of questionable “holes”, possibly corresponding to eccentrically located proximal pores. in other sections, on the other hand (pl. 1, fig. l; pl. 4, fig. d), the pore is clearly located on the axis of the lateral. based on a single tangential section (pl. 4, fig. o), the laterals of the new species are not adjoined beyond the calcareous coat. in other words, they do not or do not always form the distal, continuous assimilatory cortex typical of salpingoporella. so far, the questionable endospory is based on a single oblique section (pl. 3, fig. f). cladospory (e.g. in salpingoporella genevensis conrad et al.) is part of the defi nition of the genus salpingoporella. also in salpingoporella turgida radoičić the axial cavity and the thallus may be slightly club-shaped. one section, of s.? inopinata (gollestaneh, 1965, pl. 68, fi g. 3) not illustrated here,suggests the possible presence of a much wider, possibly aberrant “head” of thallus. 3. micropalaeontological assemblages the total thickness of the studied succession is 212m. the fahliyan formation is 150m thick and the remainder belongs to the gadvan formation which overlies the fahliyan formation in this area. based upon the micropalaeontological data, the following three geological age intervals can be separated. berriasian: the fi rst (lower) interval is about 93m thick. lithologically, it is essentially composed of limestone (bioclastic wackestone to packstone with micritization, bioturbated mudstone-wackestones (pl. 7, fig. a), pelloidal bioclastic grainstones (pl. 7, fig. c), peloidal-fenestrated grainstones (pl. 7, fig. b), mollusc fl oatstones (pl. 7, fig. g), spongiferous (spicules) packstones (pl. 7, fig. e), argillaceous wack e stones with dissolved gastropod shells (pl. 7, fig. h), lithocodium/ bacinella bindstones and rare non-fossiliferous dolomitic mudstones (pl. 7, fig. d). the calcareous green algae encountered in this interval are: salpingoporella istriana (gušić), s. pygmaea (gümbel), clypeina sp., salpingoporella circassa farinacci & radoičić, otternstella lemmensis (bernier), cylindroporella? sp., salpingoporella? inopinata n. sp., zergabriella embergeri (bouroullec & deloffre), otternstella sudgeni elliott, rajkaella sp., salpingoporella annulata carozzi, holosporella sp., salpingoporella katzeri conrad & radoičić, actinoporella podolica (alth), salpingoporella aff. piriniae carras & radoičić, terquemella sp., clypeina cf. onogosti radoičić, clypeina aff. nigra conrad & peybernès, clypeina dragastani dieni & radoičić, clypeina estevezii granier, anisoporella sp., praturlonella sp., holosporella arabica granier & brun,clypeina gr. solkani conrad & radoičić, clypeina parasolkani farinacci & radoičić. these are associated with thaumatoporella parvovesiculifera raineri, permocalculus inopinatus elliott, cladocoropsis mirabilis felix, lithocodium aggregatum elliott and bacinella irregularis radoičić. the accompanying foraminifera are essentially represented by: trocholina chouberti hottinger, t. gigantea gorbatchik, t. alpina leupold, t. elongata leupold, t. sagittaria arnaud-vanneau et al, orbitolinids, t. molesta gorbatchik, pseudocyclammina lituus yokoyama, pseudochrysalidina arabica henson, praechrysalidina infracretacea luperto sinni, trocholina campanella arnaud-vanneau et al, everticyclammina hedbergi maync, rumanoloculina pseudominima bartenstein & kovatcheva, nautiloculina oolithica mohler, trocholina delphinensis arnaud-vanneau et al, haplophragmoides sp., trocho lina cherchiae arnaud-vanneau et al, dukhania conica henson, nezzazata sp., montsalevia salevensis cha rol lais et al, vercorsella halleinensis schlagint welt, protopeneroplis ultragranulata gorbatchik and scythiloculina bancilai neagu, associating with aeolisacus inconstans radoičić, echinoid remains, mollusc fragments, sponge spicules and ammonite shells. valanginian: the second interval has a thickness of 57m. it is dominated by lithocodium/bacinella bindstones (pl. 7, fig. i), bioclastic wackestones to packstones with dissolved gastropod shells (pl. 7, fig. m), bioclastic wackestones to packstones containing aptychi and the calcareous opercula of ammonites (pl. 7, fig. j), peloidal-fenestral grainstones (pl. 7, fig. k), serpulid limestone (pl. 7, fig. l), bioclastic packstone-grainstones, peloidal-fenestral grainstones with coated grains (pl. 7, fig. n) and argillaceous wackestones with evidence of subaerial exposure (pl. 7, fig. o). geologia croatica geologia croatica 61/2–3 218 plate 1 dasycladalean algae of the kuh-e-surmeh section a zergabriella embergeri bouroullec & deloffre, berriasian, sample jht 1298. b salpingoporella annulata carozzi, berriasian, sample jht 1298. c actinoporella? cf. podolica (alth), berriasian, sample jht 1303. d salpingoporella sp. aff . piriniae carras & radoičić, berriasian, sample jht 1307. e salpingoporella annulata carozzi, berriasian, sample jht 1307. f clypeina cf. solkani conrad & radoičić, berriasian, sample jht 1307. g otternstella cf. sudgeni elliott, berriasian, sample jht 1308. h salpingoporella sp. aff . piriniae carras & radoičić, berriasian, sample jht 1313. i salpingoporella cf. circassa farinacci & radoičić, berriasian, sample jht 1316. j–m salpingoporella? inopinata gollestaneh, n.sp.(section l is the holotype), berriasian, sample jht 1317. n, o cylindroporella? sp. (basal, sterile portion of the thallus), berriasian, sample jht 1319. p holosporella arabica granier & brun, berriasian, sample jht 1319. q, s actinoporella podolica (alth), berriasian, sample jht 1319. r terquemella sp., berriasian, sample jht 1319. t salpingoporella cf. inopinata gollestaneh, n. sp., berriasian, sample jht 1320. scale: figs. a, c, i = 150 mm; figs. e, f, g, j, k, n, o, p, q, s = 100 mm; figs. b, d, h, l, m, r, t = 50 mm. geologia croaticaseyed abolfazl hosseini and marc a. conrad: calcareous algae, foraminifera and sequence stratigraphy of the fahliyan formation... 219 geologia croatica geologia croatica 61/2–3 220 plate 2 dasycladales of the kuh-e-surmeh section a salpingoporella circassa farinacci & radoičić, berriasian, sample jht 1320. b neomizzia? sp., berriasian, sample jht 1321. c salpingoporella circassa farinacci & radoičić, berriasian, sample jht 1324. d clypeina cf. solkani conrad & radoičić, berriasian, sample jht 1324. e salpingoporella annulata carozzi, berriasian, sample jht 1324. f salpingoporella sp. aff . piriniae carras & radoičić, berriasian, sample jht 1324. g, h salpingoporella annulata carozzi, berriasian, sample jht 1324. i, j neomizzia? sp., berriasian, sample jht 1324. k clypeina parasolkani farinacci & radoičić, berriasian, sample jht 1324. l dasycladalean alga, gen. & sp. indet. berriasian, sample jht 1325. m clypeina? cf. dragastani dieni & radoičić, berriasian, sample jht 1326. n-p salpingoporella? inopinata gollestaneh, n. sp., berriasian, sample jht 1327. q, r neomizzia? sp., berriasian, sample jht 1327. s salpingoporella katzeri conrad & radoičić, berriasian, sample jht 1327. t clypeina cf. solkani conrad & radoičić, berriasian, sample jht 1327. scale: figs. h, i, s = 150 mm; figs. a, b, c, d, e, g, j, m, n, q, r, t = 100 mm; figs. f, k, l, o, p = 50 mm. geologia croaticaseyed abolfazl hosseini and marc a. conrad: calcareous algae, foraminifera and sequence stratigraphy of the fahliyan formation... 221 geologia croatica geologia croatica 61/2–3 222 plate 3 calcareous algae of the kuh-e-surmeh section a clypeina parasolkani farinacci & radoičić, berriasian, sample jht 1327. b–e actinoporella podolica (alth), berriasian, sample jht 1328. f salpinogoporella? inopinata gollestaneh, n. sp., berriasian, sample jht 1328. g otternstella lemmensis (bernier), berriasian, sample jht 1328. h salpingoporella pygmaea (gümbel), valanginian, sample jht 1330. i bacinella irregularis radoičić, valanginian, sample jht 1330. j, k actinoporella cf. jaff rezoi granier, valanginian, j: sample jht 1339 & k: sample jht 1340. l clypeina cf. estevezii granier, valanginian, sample jht 1340. m-p terquemella sp.,valanginian, m: sample jht 1340 & n-p: sample jht 1346. q clypeina cf. estevezii granier, valanginian, sample jht 1346. r–t second order laterals of selliporella neocomiensis (radoičić), valanginian, sample jht 1349. scale: fig. h = 300 mm; fig. i = 200 mm; figs. a, b, c, d, e, f, g, j, k, l, q, r, s = 100 mm; figs. m, o, p, t = 50 mm; fig. n = 30 mm. geologia croaticaseyed abolfazl hosseini and marc a. conrad: calcareous algae, foraminifera and sequence stratigraphy of the fahliyan formation... 223 geologia croatica geologia croatica 61/2–3 224 plate 4 calcareous algae of the kuh-e-surmeh section a, b zergabriella? cf. embergeri (bouroullec & deloffre), valanginian, sample jht 1349. c oncoid of bacinella irregularis radoičić and lithocodium aggreatum elliott, valanginian, sample jht 1351. d salpingoporella? inopinata gollestaneh., n. sp., valanginian, sample jht 1353. e–h salpingoporella circassa farinacci & radoičić, valanginian, sample jht 1353. i dasycladalean alga, gen. & sp. indet., valanginian, sample jht 1356. j salpingoporella? cf. annulata carozzi, valanginian, sample jht 1356. k salpingoporella dinarica radoičić, hauterivian -barremian, sample jht 1358. l–p salpingoporella? inopinata n. sp., in gollestaneh, 1965, pls. 68 & 69, × 150. scale: fig. c = 300 mm; fig. f, g, h, i, j, l, m, n, o, p = 100 mm; figs. a, b, d, e, k = 50 mm. geologia croaticaseyed abolfazl hosseini and marc a. conrad: calcareous algae, foraminifera and sequence stratigraphy of the fahliyan formation... 225 geologia croatica geologia croatica 61/2–3 226 plate 5 benthic foraminifera of the kuh-e-surmeh section a trocholina sp., berriasian, sample jht 1298. b trocholina sp., berriasian, sample jht 1298. c ?mayncina sp., berriasian, sample jht 1298. d glomospira sp., berriasian, sample jht 1302. e trocholina sagittaria arnaud-vanneau et al., berriasian, sample jht 1304. f charentia cf. cuvillieri neumann, berriasian, sample jht 1305. g trocholina cf. chouberti hottlnger, berriasian, sample jht 1305. h trocholina delphinensis arnaud-vanneau et al., berriasian, sample jht1309. i trocholina cf. chouberti hottinger, berriasian, sample jht1309. j trocholina cf. gigantea gorbatchik, berriasian, sample jht1312. k trocholina delphinensis arnaud-vanneau et al., berriasian, sample jht 1312. l trocholina cf. elongata leupold, berriasian, sample jht1314. m trocholina campanella arnaud-vanneau et al., berriasian, sample jht 1315. n trocholina sp., berriasian, sample jht 1316. o pseudocyclammina lituus yokoyama berriasian,, sample jht 1317. p ?vercorsella halleinensis schlagintwelt, berriasian, sample jht 1317. scale: fig. o = 200 mm; figs. a, b, c, d, e, f, g, h, i, j, k, l, m, n, p = 100 mm. geologia croaticaseyed abolfazl hosseini and marc a. conrad: calcareous algae, foraminifera and sequence stratigraphy of the fahliyan formation... 227 geologia croatica geologia croatica 61/2–3 228 plate 6 microfossils of the kuh-e-surmeh section a lituolid foraminifera, berriasian, sample jht 1324. b mayncina sp., berriasian, sample jht 1326. c praechrysalidina infracretacea luperto sinni, valanginian, sample jht 1331. d pseudochrysalidina arabica henson, valanginian, sample jht 1336. e trocholina sagittaria arnaud-vanneau et al., valanginian, sample jht 1337. f rectocyclammina sp., valanginian, sample jht 1339. g redmondoides cf. lugeoni (septfontalne), sample jht 1340. h vercorsella sp., sample jht 1343. i ?deabarina hahounerensis fourcade et al., valanginian, sampe jht 1343. j aeolisaccus inconstans radoičić, valanginian, sample jht 1343. k nautiloculina cf. broennimanni arnaud-vanneau & peybernés, valanginian, sample jht 1352. l aulotortus sp., hauterivian-barremian, sample jht 1358. m palorbitolina lenticularis blumenbach, hauterivian-barremian, sample jht 1358. n novalesia distorta arnaud-vanneau, hauterivian-barremian, sample jht 1359. o tintinnopsella carpathica murg & filip, berriasian, sample jht 1320. scale: fig. c = 200 mm; fig. h, i, j = 75 mm; figs. a, b, d, e, f, g, k, m = 100 mm; figs. l, n, o = 50 mm. geologia croaticaseyed abolfazl hosseini and marc a. conrad: calcareous algae, foraminifera and sequence stratigraphy of the fahliyan formation... 229 geologia croatica geologia croatica 61/2–3 230 plate 7 carbonate facies types a bioturbated dolomitic mudstone, shallow subtidal deposits; sequence a, sample jht 1299. b bioclastic, pelletal and fenestral grainstone; inner ramp, transgressive deposits of sequence a, sample jht 1302. c bioclastic grainstone with trocholina cf. chouberti and other common benthic foraminifera; inner/mid ramp, transgressive deposits of sequence a, sample jht 1305. d non-fossiliferous mudstone; inner/mid ramp, transgressive deposits (before the maximum fl ooding surface) of sequence a, sample jht 1306. e spongiferous (spicules) packstone; outer ramp, maximum fl ooding surface of sequence a, sample jht 1308. f bioclastic packstone with abundant trocholina spp.; inner/mid ramp, highstand deposits of sequence a, sample jht 1315. g mollusc fl oatstone; inner/mid ramp, highstand deposits of sequence a, sample jht 1316. h argillaceous wackestone with dissolved gastropod shells; inner/mid ramp, highstand deposits of sequence a, sample jht 1320. i lithocodium/bacinell bindstone; inner ramp, highstand deposits of sequence a, sample jht 1333. j bioclastic packstone with aptychi (calcareous opercula of ammonites); inner ramp, highstand deposits of sequence a, sample jht 1337. k peloidal, fenestral grainstone; inner/mid ramp, transgressive deposits of sequence b, sample jht 1339. l serpulid limestone; inner ramp, shallow subtidal deposits of sequence b, sample jht 1345. m bioclastic wackestone with dissolved gastropod shells; inner ramp, shallow subtidal deposits of sequence b, sample jht 1347. n peloidal grainstone and coated grains; inner/mid ramp, shallow subtidal deposits of sequence b, sample jht 1348. o subaerial exposure facies with pelecypod shell fl oatstone, dissolved shells and iron oxides; upper sequence boundary of sequence b, sample jht 1356. scale: fig. a, b, c, d, e, f, g, i, j, k, l, n, o = 300 mm; fig. h, m = 200 mmm. geologia croaticaseyed abolfazl hosseini and marc a. conrad: calcareous algae, foraminifera and sequence stratigraphy of the fahliyan formation... 231 geologia croatica geologia croatica 61/2–3 232 as shown by the range chart distribution (fig. 2), most of the benthic foraminifera and calcareous green algae found in the berriasian interval are also present in the valanginian. the main difference is the fi rst occurrence of some benthic foraminifera and dasycladalean algae such as: choffatella sp., debarina hahounerensis fourcade & al, redmondoides cf. lugeoni (septfontalne), nautiloculina broennimanni arna ud vanneau & peybernès, cuneolina laurenti sartoni & crescenti, vercorsella sp. falsogaudrynella tealbyensis bartenstein, conicospirillina basiliensis mohl er, selliporella neocomiensis (radoičić) and actinoporella jaffrezoi granier. it is also worth mentioning that the following important calcareous green algae found in the previous (berriasian) interval are absent from the valanginian: clypeina dragastani dieni & radoičić, otternstella lemmensis (bernier), o. sudgeni elliott, salpingoporella istriana (gušić) and holosporella arabica granier & brun. among the benthic foraminifera, trocholina gigantea gorbatchik, charentia cuvillieri neumann and trocholina chouberti hottinger are also missing from the interval. based on the faunal and fl oral content, a valanginian (possibly early valanginian,) age can be assigned to this interval. hauterivian-barremian: the third, 62m thick interval of the studied surface section belongs to the lower part of the gadvan formation. this formation mainly comprises marl and some thin to medium size intercalations of clean limestone (bioclastic packestone). most of the gadvan formation (the shaly portions) is covered by vegetation so that no samples could be taken. only two surface samples were prepared from the limestone horizons of this formation which are dominated by: palorbitolina lenticularis blumenbach, salpingoporella dinarica radoičić, debarina hahounerensis fourcade et al., choffatella decipiens schlumberger, trocholina sagittaria arnaud-vanneau et al, t. oduk paniensis dessauvagie, aulotortus sp., novalesia distorta arnaudvanneau, dukhania sp., falsogaudryinella tealbyensis bartenstein, dukhnia conica henson and oncoids of lithocodium aggregatum elliott with bacinella irregularis radoičić, associated with echinoid remains, mollusc fragments and corals. based upon the aforementioned microfossils, an hauterivian – barremian age is assigned to this part of the gadvan formation in this area. 4. depositional environments based on the analysis of the faunal and fl oral content of 254 thin-sections, and also on standard facies analysis criteria (texture, grain types and sedimentary features), three main depositional environments have been identifi ed (fig. 3). inner ramp/restricted platform: the inner ramp (shallow subtidal) depositional environments generally include the open lagoon, inner shoal and restricted lagoon. in the studied section, most of the deposits belong to the inner ramp environment, especially the open lagoon and inner shoal, which are characterized by the presence of bioclastic wackestone– packstones and bioturbated wackestone-packstones (pl. 7, fig. a). peloidal-bioclastic fenestral packstones to grainstones are also observed, indicative of the upper subtidal environments (pl. 7, figs. b–c). most of the deposits are dominated by lithocodium/bacinella bindstones which are interpreted as typical shallow subtidal deposits (pl. 7, fig. i). the inner ramp deposits are represented by a highly diversifi ed fauna and fl ora (fig. 4) such as: calcareous green algae (salpingoporella, actinoporella, clypeina, otternstella, zergabriella and rare selliporella, associating with lithocodium/bacinella). among the large benthic foraminifera, pseudocyclammina, choffatella, cuneolina, trocholina and miliolids are common, while dukhania and orbitolinids are rarely observed. these are associated with abundant mollusc fragments, dissolved gastropods, corals and rare echinoid remains. the calcareous green algae dominate and prevail over benthic foraminifera in this environment. the serpulid limestone is also present in some parts, marking a transition from carbonate ramp stage to a platform stage (pl. 7, fig. l). the occasional presence of tintinnids (tintinnopsella carpathica murg & filip) and echinoids (saccocoma) indicates a temporally limited connection to open platform environments. the miliolid–ostracod carbonates which indicate restricted lagoonal environments are extremely rare. they occur in the middle part of the section and are mainly mud supported, with wackestones. based upon the abundant calcareous green algae, it is suggested that the water depth varies from 5m to 10m in this environment. mid ramp/margin to open platform: this depositional environment is characterized by the presence of abundant large benthic foraminifera associated with calcareous green algae. the texture of these deposits varies from bioclastic wackestones (low energy) to peloidal-bioclastic packstone–grainstones indicative of high energy conditions. the main faunal content of this depositional environment includes benthic foraminifera such as pseudocyclammina, cuneolina, trocholina, orbitolinids and dukhania, associated with abundant echinoid remains, ammonite shells and rare sponge spicules. among the dasycladalean algae, salpingoporella pygmaea, salpingoporella katzeri, salpingoporella? inopinata n. sp., salpingoporella istriana and selliporella neocomiensis are rather common, whereas other species of salpingoporella as well as clypeina, actinoporella, otternstella and lithocodium/bacinella are rarely present. in our opinion, a water depth of 10–20m is estimated for this depositional environment. outer ramp/platform slope: in the kuh-e-surmeh section, the deposits containing pelagic organisms (sponge spicules, saccocoma, ammonite shells and abundant echinoid remains), rare in situ benthic foraminifera (dukhania and small valvulinids) and very rare salpingoporella? inopinata n. sp., salpingoporella pygmaea, s. katzeri and s. istriana have been assigned to the outer ramp to platform slope depositional environment. other benthic foraminfera in this environment including species of trocholina, falsogaudryinella, choffatella, cyclamminids, praechrysalidina, debarina, rummanolo culina, nautiloculina, cuneolina and calcareous green algae such as other species of salpingoporella and clypeina (fig. 3), were probably brought in by storms and are not in situ. the lithology of these deposits is marked by mud supported cargeologia croaticaseyed abolfazl hosseini and marc a. conrad: calcareous algae, foraminifera and sequence stratigraphy of the fahliyan formation... 233 fi gu re 2: biostratigraphy, sedimentology and sequence stratigraphy of the fahliyan and gadvan formations in kuh-e-surmeh. geologia croatica geologia croatica 61/2–3 234 bonates, commonly with wackestones and packstones (pl. 7, fig. e). based on the faunal composition, it is expected that the water depth ranges from 20m to some 40m. 5. sequence stratigraphy the presented sequence stratigraphic model is based on the defi nition of vail et al. (1991). herein we have amalgamated possibly low stand and transgressive system tracts as transgressive deposits. three 2nd and 3rd order sequences have been recognized throughout the studied section, ranging from about 2 to 8 my (fig. 2 and fig. 4). each sequence is shown by two triangles or polygons, differently coloured. if a/s > 1 (accommodation more than sediment supply), this indicates the transgressive trend, and if a/s < 1, the regressive trend is represented. as for the sequence boundaries, two inferred categories are shown in fig. 2 and fig. 4: sb i, corresponding to the type i with evidence of exposure; sb ii, corresponding to the type ii with a shallowing upward trend. fig. 4 shows the benthic foraminiferal diversity increases during the transgressive phases, reaching a maximum value before the maximum fl ooding surfaces, and decreases or remains constant during the regressive stages, fi nally reaching the minimum at the sequence boundaries. instead, the maximum diversity of calcareous algae occurs in the fi rst phase of transgression as well as in the last phase of highstand, when the sea level is intermediate. conversely, their lowest diversity occurs in or close to the maximum fl ooding surface (mfs), since during the sea level rise, the environmental conditions (light, temperature, salinity and substrate) were not suitable for fl oral productivity (fig. 4). sequence a: the thickness of this sequence is 106m. the lower sequence boundary is a regional discontinuity located between the hith anhydrite and the fahliyan formation (late jurassic-early creataceous) in the zagros basin as well as in the arabian plate (sharland et al. 2001, 2004). tentatively this sequence boundary is placed in type і, corresponding to an exposure. the sequence represents a deepening-shallowing trend, with shallow subtidal (inner ramp), inner to mid ramp and outer ramp environments. the maximum fl ooding surface (mfs) is marked by the presence of abundant sponge spicules and echinoid remains, with rare benthic foraminifera and calcareous green algae; it is assigned to the mid to outer ramp environments. the highstand deposits show a seaward stepping and regressive cycle, with a decreasing diversity of the benthic foraminifera and an increasing diversity of the calcareous green algae (fig. 4). the sequence is assigned a berriasian – lower valanginian age, quite comparable with the arabian plate sequence stratigraphy scheme of sharland et al. (2001, 2004). sequence b: the second partly covered sequence of the fahliyan formation has a thickness of about 44m. it includes deepening and shallowing upward deposits, with inner ramp/ lagoonal to mid ramp and also outer ramp deposits. the transgressive trend begins with bindstone mats overlain by high energy and low energy deposits denoting mid ramp environments. the maximum fl ooding surface is dominated by sponge spicules, ammonite shells, saccocoma and echinoid remains. the highstand deposits are marked by seaward stepping with the presence of inner ramp deposits. the lower sequence boundary is normal (sb ii, or type ii), whereas the upper sequence boundary is of type i, with evidence of subaerial exposure (iron oxide-rich, karstifi cation and hard ground) illustrated in pl. 7, fig. o. this sequence is given an early valanginian age, again showing an interesting relationship with the sequ ence bundle identifi ed in the arabian plate (sharland et al., 2001, 2004). sequence c: this 62m thick sequence belongs to the lower part of the gadvan formation. as mentioned above, most parts of the gadvan formation are covered. the soft materials in the basal part of the gadvan formation are interpreted as being transgressive deposits with a deepening upward trend. in the mid part of the gadvan formation, at the top of the sampled section, some thin to medium sized, clean limestone beds occur indicating inner to mid ramp depositional environments. this interval is formally called the khalij member. it can be traced over the whole of the zagros basin as well as in the arabian plate. by similarity with the sequence stratigraphic model for the arabian plate (sharland et al., 2004), the upper sequence boundary is placed at top of the limestone horizon of this member. at present, there is no data, in the studied section, to document the transgressive trend and the maximum fl ooding surface. fi gu re 3: environmental distribution of the main calcareous green algae (especially dasycladalean), some benthic foraminifera and other biota (sponge spicules and echinoids) in the studied succession. geologia croaticaseyed abolfazl hosseini and marc a. conrad: calcareous algae, foraminifera and sequence stratigraphy of the fahliyan formation... 235 fi gu re 4: biotic diversity of benthic foraminifera and calcareous green algae, at the generic level in the study section of kuh-e-surmeh. geologia croatica geologia croatica 61/2–3 236 6. palaeoecology and palaeobathymetry environmental indicators used in this study are shown in fig. 3. concerning the dasycladalean algae, extant species usually live in normal (euhalyne) waters, within the 20°c isocryme, in the infralittoral environment defi ned as corresponding to the habitat of the marine phanerogams. there are exceptions however, which were reviewed by berger & kaever (1992). the same applies to the fossil record. most species identifi ed in the kuh-e-surmeh section lived in the inner ramp environment, while three species deserve special interest. the fi rst species, salpingoporella dinarica radoičić, was very tolerant, as shown by the fact that it fl ourished in low energy, restricted marine environments (for a review of the genus salpingoporella, see carras et al., 2006). the second species, salpingoporella pygmaea (gümbel), is typically found in open marine, high energy, reefal platform margins. in abu dhabi (aziz & el-sattar, 1997) it is taken as a marker (salpingoporella pygmaea subzone) believed to indicate a valanginian age in outer shelf areas. (actually, the species, which has several synonyms, ranges from the bathonian to the aptian). the third species is zergabriella embergeri (bouroullec & deloffre). quoting bucur & săsăran (2005), based on trace element analysis carried out by jaffrezo & renard (1979), when associated with charophytes, the species indicates a hypersaline environment, rather than a brackish one as would be suggested by biotic and facies data. the benthic foraminifera and calcareous green algae diversity curves are shown in fig. 4. the diversity index of benthic foraminifera ranges from 1 (minimum) to 15 (maximum), whereas this index varies from 0 (minimum) to 17 (maximum) for calcareous green algae. this study reveals that each depositional environment has a typical assemblage of benthic foraminifera and calcareous green algae. concerning the benthic foraminiferal diversity, the maximum value is observed throughout the mixed sediments of the inner ramp to mid ramp environments (index from 4 to 15). the lowest diversity corresponds to the shallower subtidal and lagoonal environments, and, also to the outer ramp (index from 1 to 8). by comparison, the highest diversity values of calcareous green algae are found in open lagoon and shoals, with indexes ranging from 3 to 17, while the least values refer to the platform slope environments, with values ranging from 0 to 4. among the calcareous green algae, the order dasycladales is frequently represented. some species of the family dasycladaceae are reported for the fi rst time from the zagros basin, e.g. zergabriella embergeri, salpingoporella katzeri, s. istriana, s. pygmaea, and s. circassa. the latter species is apparently reported for the fi rst time from southern tethys. the family acetabulariaceae is also present, with the subfamily clypeineae including species such as clypeina estevezi, c. solkani, c. parasolkani and c. dragastani, which are reported for the fi rst time from the zagros basin. 7. conclusions based on micropalaeontological data from the kuh-e-surmeh section, the ages of the fahliyan and gadvan formations have been determined. the fahliyan formation is of berriasian and valanginian age, while a hauterivian to barremian age is assigned to the gadvan formation in the study area. sequential interpretation reveals the presence of at least three sequences comprising several parasequences throughout the studied succession. two sequence boundaries are considered to belong to the type i, with subaerial exposures believed to correspond to regional discontinuities. one sequence boundary belongs to the type ii. species of the dasycladaceae and the subfamily clypeineae are reported for the fi rst time from the zagros basin and/or from southern tethys. one new species of dasycladalean algae, salpingoporella? inopinata gollestaneh, n. sp. is provisionally described, awaiting additional material. palaeoecological and palaeobathymetric investigations indicate that the studied samples were deposited in shallow water, internal subtidal (open lagoon) to external subtidal (inner to mid ramp) and platform slope (outer ramp) environments, in water depths of 5m to 40m, with salinities ranging from normal marine to saturated (hypersaline). acknowledgement the authors wish to express their deep gratitude to the exploration manager of the national iranian oil company (nioc) for permission to publish this paper. many thanks also for the assistance and technical support of mr. seyed hassan bahrami-zadeh sadjadi of the department of geological and geochemical researches and studies of the nioc. we are grateful to prof. rolf schroeder (frankfurt) for checking the benthic foraminifera and providing fruitful advice. we are also greatly indebted to dr. rajka radoičić (belgrade) and dr. nicolaos carras (athens) for their most helpful and critical review of the different species of dasycladales. references aziz, s.k. & el-sattar, m.m.a. (1997): sequence stratigraphic modeling of the lower thamama group, east onshore abu dhabi, united arab emirates. – geoarabia, 2, 179–202. berger, s. & kaever, m.j. (1992): dasycladales: an illustrated monograph of a fascinating algal order. – thieme, stuttgart, 247 p. bucur, i.i. & săsăran, e. (2005): relationship between algae and environment: an early cretaceous case study, trascau mountains, romania. – facies, 51, 274–286. carras, n., conrad, m.a. & radoičić, r. (2006): salpingoporella, a common genus of mesozoic dasycladales (calcareous green algae). – rev. de paléobiol., 25, 457–517. conrad, m.a. & grábner, s. (1974): salpingoporella hispanica, n. sp., une dasycladale du barrémien des pyrénées espagnoles. – c. r. soc. phys. hist. nat. genève, 9/1–3, 30–39. gollestaneh, a. (1965): micropalaeontological study of the upper jurassic and lower cretaceous of southern iran. – unpubl. phd thesis, university college, london, 629 p. gollestaneh, a. (1974): the biostratigraphy of the khami group and the jurassic – cretaceous boundary in fars provience (southern iran). – bulletin du b.r.g.m (deuxieme série), section iv, 3, 165–179. gollestaneh, a. (1979): the stratigraphic distribution of fossil calcareous algae in southern iran – in: 2nd international symposium on fossil algae. bull. cent. rech. explor. – prod. elf-aquitaine, 3, 619–624. geologia croaticaseyed abolfazl hosseini and marc a. conrad: calcareous algae, foraminifera and sequence stratigraphy of the fahliyan formation... 237 jaffrezo, m. & renard, m. (1979): elements en traces de calcaires ŕ dasycladales et charophytes. – bull. centr. rech. elf-aquitaine expl. – product, mém. 3, 639–649. setudehnia, a. (1978): the mesozoic sequence in s.w. iran and adjacent areas. – journal of petroleum geology, 1, 3–42. sharland, p.r., archer, r., casey, d.m., davis, r.b., hall, s.h., heward, a.p., horbury, a.d. & simmons, m.d. (2001): arabian plate sequence stratigraphy. – geoarabia special pub. 2, 371 p. sharland, p.r., casey, d.m., davis, r.b., simmons, m.d. & sutliffe, o.e. (2004): arabian plate sequence stratigraphy. – geoarabia, 9/1. vail, p.r., audemard, f., bowman, s.a., eisnet, p.n. & perez-cruz, c. (1991): signatures of tectonics, eustasy and sedimentology – an overview. – in: einsele, g., ricken, w. & seilacher, a. (eds.): cycles and events in stratigraphy. springer, berlin, heidelberg, new york, 617–659. manuscript received december 22, 2007 revised manuscript accepted may 19, 2008 1. introduction neuropterids and alethopterids with reticulated veins are known from many coal basins to the north of the variscan mountains. their relationship with non-reticulated members of the same groups is widely assumed, although only the transition from neuropteris to reticulopteris has been unequivocally documented (josten, 1962; tenchov & popov, 1990). gothan (in potonié, 1910) suggested that there was a westphalian intermediate form between the open-veined alethopteris and the anastomosed veined lonchopteris, which he called lonchopteridium. later, gothan (1953, pl. 13 fig. 2, 2a) figured a specimen of alethopteris valida with clear anastomoses. egemen (1958, pl.6, fig. 1,1a) illustrated a specimen of neuropteris gigantea from the kozlu formation, (langsettian substage, turkey), that has several anastomoses to the left of the midvein. although he did not mention them in the figure explanation, he stated in the text (egemen, 1958, p. 12–13) that the merging of lateral veins indicates “…a gradual change towards drier and more terrestrial conditions of habitat…”. potonie (in crookall, 1959, p.135) reported paripteris specimens with anastomoses, but did not specify the habitats, geographical positions or stratigraphic horizons. in bulgaria (fig. 1), the svoge coalfield lacks any plants with reticulated veins (tenchov, 1976; 2011). in the dobrudzha coalfield in northeastern bulgaria, in contrast, reticulate veining is extremely widespread. some of the earliest examples are of cardiopteridium waldenburgense zimmermann (samples 5750 and 5775), from the pendelian rakovski formation, in which single anastomoses have been observed. examples of paripteris with single anastomoses or groups of anastomoses are frequently obab stra ct alethopteris, lonchopteris, paripteris, linopteris and reticulopteris are abundant pteridosperm fronds in the pennsylvanian-age dobrudzha coalfield. the transition from fan-shape to reticulate veining in lonchopteris, linopteris and reticulopteris and in laveineopteris to reticulopteris is documented. the most probable cause for this is the decrease in humidity; in addition to temperature controls on the geographic distribution. the form and positioning of anastomoses are discussed. keywords: carboniferous, pteridosperms, reticulation, palaeoecology, drying, cooling geologia croaticageologia croatica vein reticulation in seed ferns of the dobrudzha coalfield bulgaria  yanaki georgiev tenchov geological institute of the bulgarian academy of sciences, g. bonchev street block 24, 1113 sofia, bulgaria; (ytenchov@abv.bg) doi: 104154/gc.2012.24 geologia croatica 65/3 351–360 3 figs. 1 tab. 2 pls. zagreb 2012 figure 1: bulgaria; location of the dobrudzha coalfield – dc. geologia croatica 65/3geologia croatica 352 served (e.g. pl. 1, figs. 2–4, 6, 7) (tenchov & popov, 1987b). there are at least seven linopteris species observed in the balchik group, ranging in age from langsettian to stephanian a (tenchov & popov, 1987a), some of which include examples with imperfect reticulation (pl. 1, figs 5; pl. 2, figs 8, 10). the transition from neuropteris to reticulopteris has been documented between the upper duckmantian to upper bolsovian parts of the balchik group (tenchov & popov, 1990), in concordance with what has been reported from the ruhr coalfield (josten, 1962). lonchopteris is represented by six species (tenchov, 2004a) ranging from the langsettian mogilishte formation, to the bolsovian middle makedonka formation. no clear evidence has been discovered in the balchik group of the transition between alethopteris and lonchopteris, such as documented by gothan (1910, 1953) in the early langsettian bochum formation of the ruhr and aachen basins, but deposits of this age are not well-preserved in dobrudzha. 2. material and storage of the samples at present, 3600 samples of carboniferous and permian fossil plants from bulgaria are publicly accessible. they are stored in the palaeontology and stratigraphy museum of the mining geological university, “st. ivan rilski”, sofia. information on their storage is electronically available at the museum. another c. 5000 samples are awaiting a place of long-term storage and are not publicly accessible. numerous specimens of paripteris that have occasional vein anastomoses are known from the dobrudzha megaflora, mainly belonging to the paripteris gigantea-paripteris pseudogigantea complex, and rarely to other species. there are also some linopteris specimens that exhibit imperfect anastomoses (table 1). figure 2 shows the distribution of these species in the dobrudzha sequence, along with the distribution of other reticulated species or groups of species. most examples of reticulated paripteris are isolated pinnules occurring in sandstones, siltstones and claystones, in fining upwards sequences, and only rarely immediately above a coal seam. coarser grained sediment is more common in the southern part of the dobrudzha coal basin, where there are distal parts of fans that entered the swamp of the basin. any 1 metre thickness of core of a borehole in the coalfield is assigned a standard level (sl). the concept of standard levels was developed by tenchov (1993) to facilitate correlation between different borehole sections within the dobrudzha coalfield, and was based around a limited number of stratigraphic levels (mainly coal seams), that could be identified across the basin. the base of the sequence is assigned an sl value of 0 m, and the top an sl value of 1600 m. 3. geological background 3.1. palaeogeography the landscape around the dobrudzha depression (fig. 3) is part of the variscides. from south to north it consists of the following. 1. the variscan range with an intermontane depression (the svoge coalfield) maybe 2000 meters above sea level. in this depression, the lower temperatures influenced the plant community more strongly than in dobrudzha basin. the air humidity in the svoge grabens was less a factor maybe due to the altitude, the river in the depression, and maybe the high mountain ranges around the depression. 2. the variscan foreland with a maybe 80 km wide alluvial plane to the south of seltse fault. erosion prevailed close to the depression. the sand substratum drained rainwater away quickly and deeply. 3. a depression to the north of the seltse fault, the dobrudzha coalfield, lay at about 190 meters above sea level (tenchov, 1993) and drained waters from the alluvial plane. that depression starts subsiding from yeadonian times. it remained at a higher elevation than the russian plate and lower than the foreland alluvial plane. swamps, lakes and floodplains covered the depression partly and sometimes completely. river beds occurred mainly near the delimiting faults. 4. another depression with swamps and maybe lakes with mostly clayey sedimentation was established by the nanevo-1 borehole. the water table here was at or near the surface. 5. the shabla fault, which delimits the variscan realm from the russian platform to the north, was formed at about the end of late viséan times. the devonian and tournaisian deposits to the north and south of that fault are shallow-marine and their distribution does not permit any clear differentiation between the tectonic units at that time. the russian table 1: number of standard levels1 with paripteris and some linopteris species. paripteris species vein meshes absent some vein meshes present p. gigantea p. pseudogigante2 357 39 p. linguaefolia 37 3 p. schutzeii 90 2 linopteris species perfect reticulation imperfect reticulation l. neuropteroides 85 2 l. havlenaii 25 03 l. minor 70 1 l. brongniartii, l. subbrongniartii 163 04 1 a standard level is an interval of strata 1 m thick and so may contain many individual pinnules or fragments of pinna. 2 the isolated pinnules of paripteris gigantea and paripteris pseudogigantea cannot be separated as different species; this will be the subject for a separate study. 3 the particular form of reticulation in linopteris havlenaii makes it difficult to identify imperfect reticulation. 4 in the polyantsi and gurkovo formations, paripteris pinnules with reticulate veining and linopteris pinnules with imperfect reticulation have not been observed. yanaki georgiev tenchov: vein reticulation in seed ferns of the dobrudzha coalfield bulgaria geologia croatica 353 figure 2: distribution of reticulated species in the dobrudzha coalfield. geologia croatica 65/3geologia croatica 354 epicontinental sea in the donets region started to regress and sink intensively at about the end of viséan times. at about the beginning of westphalian times, the sea withdrew from both the bulgarian and romanian parts of the dobrudzha territory; the stratigraphically youngest marine deposits that have been recognised are late viséan to early namurian in the ograzhden borehole in bulgaria (boncheva et al., 1994) and namurian to early westphalian in the dobromiru borehole (fig. 3) in romania (jordan et al., 1987). spassov & yanev (1966) reported rooted soils in the ograzhden borehole and interpreted them as paralic deposits, but they are in fact siltstones with allochtonous plant remains. i have personally examined the entire core of the ograzhden borehole and there are no stigmaria rooting structures or root disturbed sediments. 6. a gulf of the russian epicontinental sea with paralic deposits found in the dobromiru borehole (jordan et al., 1987) marks a regression. 3.2. sedimentation processes during late viséan times in the variscan foredeep of northern bulgaria, the trigortsi formation was established. the lower part of the formation consists mainly of shallow marine claystones, with three thin limestone interbeds yielding foraminifera typical of the russian epiplatform sea (tenchov, 2004b). as a result of marine regression the region gradually changed to being a flat coastal plain with subaeral sedimentation and erosion. the lower part of the next, rakovski formation (the konare member) consists of claystones, siltstones, sandstones and thin coal layers, and has yielded megaflora remains. the lower and middle part of the overlying irechek member consists mainly of sandstones with specific coal and claystones pebbles. close to the faults that delimit the basin, sandstones prevail, as shown in r60 and all boreholes in the southern part of the depression (see tenchov, 2004b, figs 3–6), but in the north and central boreholes claystones become frequent. the thickness of the irechek member is up to 400 m, which indicates the minimum subsidence of the depression. at the top of irechek member in the central and northern part of the depression, the sediments are finer and even some thin coals are formed, which suggests relatively calm faulting. the part of the irechek member in the depression (borehole 73) contains cardiopteridium waldenburgense, abundant lyginopteris (l. stangeri, l. schlehanii, l. larischii, l. divaricata), neuropteris cf. antecendens, paripteris gigantea, mariopteris acuta, and one specimen of neuralethopteris sp. (tenchov & cleal, 2010). the megaflora indicates a late visean to pendelian age. the palynoflora (dimitrova, 1993) indicates the same age, though dimitrova split the interval into two subzones. the two palynological associations were obtained from two different rock associations – the lower from fluvial deposits, the upper from floodplain sediments with some swamp deposits (including coal); these deposits were laterally adjacent and not in sequence. quartz sandstones and conglomerates farther to the north in the depression mark the location of a sand bar (tenchov, 2004b, figs 7, 8). some 20 km to the northeast, the borehole r1-krapets reached pendleian marine deposits with a marine fauna including cravenoceras leion (spassov in: spassov & yanev, 1966). a break in sedimentation with an impressive change in megaflora composition occurs after the pendleian and before langsettian times; a similar break occurs in the silesian basins. after the break, about 1600 m of langsettian to stephanian a, coal bearing sediments were deposited in the depression. during this time, the main source of the clastic sediments that fill the dobrudzha coal basin was south of the seltse fault. that area seems to have been a subaerial plain, slightly inclined to the north, covered with late visean sediments of the konare member of the rakovski formation and the trigortsi formation. there is no borehole near the seltse fault that enters below the permian strata. about 60 km to the south, the marash r1 borehole passes through the konare member, which consists mainly of sandstones with 50–60 % well rounded quartz grains, and including rare plant remains (fig. 3). the lack of pebbles indicates that the catchment area was far to the south. sedimentation occurred in an alluvial plain with migrating rivers that transported the eroded material to the dobrudzha coal basin. coal grains, fusenized parts of lycophyte, articulate and fern stems, as well as numerous leaves of pteridophylls, mainly of paripteris and linopteris, were imported into the depression. figure 3: the variscides in bulgaria. explanation in the text. yanaki georgiev tenchov: vein reticulation in seed ferns of the dobrudzha coalfield bulgaria geologia croatica 355 these all indicate that areas with vegetation cover and also some swamps were very common away from the river beds. the coals are of low ash content and their composition indicates that the water basins in the swamps were of low dynamics (nikolov & stefanova in nikolov, 1988, pp. 121–126). the bezvoditsa borehole is about 10 km to the west of the dobrudzha coal basin and passes through a succession with less sandstone and more claystones, and rare thin coal seams. plant remains were frequently collected, mainly of calamites. the floral composition (bothrodendron sp., lyginopteris sp., and diplothmema adiantoides) in the upper part is similar to that of the topmost layer of the irechek member. erosion in the alluvial plain and sedimentation within the dobrudzha coal basin was controlled by tectonic activity at the delimiting faults and in the variscan range, as well as by more intensive rainfall. in two, possibly three episodes, erosion and then fluvial conditions invaded the dobrudzha depression (tenchov 1993). this first occurred about the end of duckmantian times when the seltse fault was activated. drainage in the depression at the time was halted, and a 76 metre deep erosion channel is recorded (borehole 105), followed by sedimentation of the vranino formation. the lowermost 3-4 metres of the formation consist of sandstones, mainly grains of massive metamorphic rocks (popova, in: nikolov, 1988), indicating active uplift of the variscan range to the south. these are followed by mainly volcaniclastic sediments, as well as red-coloured quartz. drainage in the depression was restored by some unknown means. to the south of the seltse fault, erosion became less active and sedimentation of the lower part of makedonka formation began. the riverbeds were filled first. frequent landslides here and there dammed the valleys and created temporary swamps. the collected megaflora from the cover of the coal layers and close to the swamps indicates similar conditions to the south of the seltse fault. autochtonous plant remains are present, among them numerous lyginopteris, lonchopteris, mariopteris, eusphenopteris and sphenopteris, pinnules of paripteris with normal veining or with some anastomoses, and linopteris with occasionally imperfect reticulation. the vein meshes indicate that the plants suffered from a lack of water due to dry air and deep drainage caused by the sandstones. evidence that swamp-lake conditions were discontinued for a second time is found in the upper part of makedonka formation, with erosional down-cutting of up to 115 m being recorded (borehole 147). the infill there is with oligomictic quartz, to quartz sandstones and there are no clay particles to filling the porosity of the sands. this composition indicates long-term weathering to the south, which seems to have taken place at the same time as the formation of the m5 – m12 coal-bearing interval in the upper part of the makedonka formation, and can be correlated with the duckmantian – middle bolsovian interval in the paralic coal basins in western europe. coal grains and plant fragments are rare in the velkovo formation with vegetation cover probably temporarily restricted to the south. swamp-lake conditions were discontinued for a third time after deposition of the polyantsi formation, which is overlain by the lowermost part of the gurkovo formation. in this case, however, the analogy is less obvious. 4. the relationship between paripteris and linopteris at present around the european variscan range the following paripteris – linopteris couplets have been recognised: • paripteris gigantea and linopteris neuropteroides; • paripteris pseudogigantea and linopteris subbrongniartii; • paripteris linguaefolia and linopteris havlenaii; data from the dobrudzha coalfield also point to a connection between paripteris schutzeii and linopteris minor. the rare linopteris regniezii laveine also has similar shaped pinnules to linopteris minor and may indicate a separate trend in vein reticulation in another area. in all these cases the non-reticulated specimens of paripteris continue to exist in parallel with their reticulated equivalent linopteris species. however, several other linopteris species including linopteris brongniartii and linopteris bunburii appeared later, and they have no clear analogues among the paripteris species. most probably these later linopterids did not arise through reticulation of paripterids, as many of them appear after the disappearance of paripteris. other post-bolsovian linopterids have vein meshes resembling those of l. neuropteroides. these species are similar to l. brongniartii and linopteris obliqua (zodrow et al., 2007), but the latter have shorter mainly hexagonal meshes. reticulation in paripteris is observed only in large pinnules. it seems that in young pinnules near the top of the frond, the water supply is regular. vein meshes are never observed in the smaller, orbicular pinnules. the distribution of meshes in different parts of the pinnules may be related to greater solar exposure. the size of the meshes decreases from the mid rib towards the pinnules border. the form of the meshes (areolas), which affected the space between the veins of a leaf, resulted from several factors: 1. coalescence of undulating lateral veins with two forms: pseudoanastomosis (the laterals touch only), and anastomosis (accretion of adjacent veins). such vein meshes develop between veins of equal rank and is seen in lonchopteridium and reticulopteris. 2. connection (junction) of two neighbouring lateral veins realised through the lower order splitting of a lateral vein and another split one level higher; giving a wedge appearance. the vein meshes can be rhomboidal (four-sided), pentagonal, or hexagonal. this is best seen in l. neuropteroides. 3. mutual delta-formed crossing of laterals that produces rhombic meshes (lonchopteris eschweilleri, linopteris regnietzii). geologia croatica 65/3geologia croatica 356 towards the end of the pinnule, the meshes become isometric, usually hexagonal. this leads to homeomorphism of the meshes in linopteris brongniartii, barthelopteris germarii, lonchopteris silesiaca, l. rugosa and l. elegans. the isometric hexagonal form permits the density and regularity of veining to be maximised, and was important for equalising water distribution to all cells because it ensured the shortest distance between the water supply lines in the pinnules and the individual cells. therefore, reticulation of pinnules is an organisation for dealing with water supply and water deficit compensation. linopteris and reticulopteris survived many climatic changes and, in contrast to lonchopteris, disappeared in the permian period. maybe the shedding of pinnules and the formation of hairs helped them survive. 5. palaeoecology there may be many reasons why a single genus or species evolves, but the transformation of numerous taxa in one habitat indicates that a common factor may have been at work. krassilov (1972) reviewed the palaeoecology of plants, including the effects of changes in temperature and air humidity. 5.1. cooling according to data cited by frakes (1979), the drop in levels of atmospheric co2 during namurian and mid-westphalian times caused a 25 °c drop in temperature. this had several consequences. some plants became extinct, but others migrated to lowland regions with temperatures similar to those of their previous habitats. it was somewhat easier for true ferns, and to a degree for seed-ferns. migration from the cooling northern areas towards the warmer southern areas, across the variscan range through dry-land areas, is possible. in the european variscan range however, there were areas that were not high. some were even below sea level, such as the danube iron gate in central and west serbia, where marine fauna from the russian epiplatform sea penetrated the tethys; and the straits or sea of marmora, where a marine northern fauna penetrated the palaeotethys during viséan-namurian times. such migrations may have been accomplished via some intermountain depressions with high altitude, such as svoge (tenchov, 1976); lower silesia, and the caucasus basins. in the latter area, paripterids but no linopterids existed; there were few or no alethopteris, lonchopteris and mariopteris, and many eusphenopteris (anisimova, 1979). some of the depressions at lower elevations such as the saar-lorraine and the southern part of the briannçonaise alps, and the turah mountains in austria and switzerland frequently host linopteris, while linopteris is not known or is extremely rare in the northern territory of the variscan foredeep (upper silesia, donets, lvov-volinsk), even in northern parts of the westeuropean variscan foredeep. 5.2. water supply regime the periodic drying that started in pendeleian times to the north of the variscan range is most probably related to the growing area of dry land, which led to the continentalisation of the climate, combined probably with a rain shadow effect caused by the rising variscides. it is unlikely that the narrow palaeotethys provided enough moisture for the atmosphere. this is directly comparable to the contemporary low influence of the mediterranean on rain fall regimes in the inner parts of eastern europe. the gradual drying of pennsylvanian climates is reflected in the seed ferns. their fronds were richly covered in hairs, had more linear, narrower and smaller pinnules, dense lateral veins, and a tendency for the pinnules to be shed. there was a history of increasing retardation in frond development. it is also reflected in their branches and reproductive organs. reticulation in seed ferns also reflects a scarcity of water. 5.3. co2 deficit an example of this is the extinction of sigillaria and lepidodendron during bolsovian times and their replacement by species with a smaller habit. newcomers from the high mountains may have had some advantage in this respect, because of the lower atmospheric content of co2 at higher altitudes, due to that gas being heavier than other components of the atmosphere. evolution also acted here, driving adaptation to changing conditions. 6. discussion linopteris neuropteroides and its predecessor paripteris gigantea both inhabited alluvial plains and intramontane depressions. p. gigantea became extinct during cantabrian times, probably due to aridisation, but l. neuropteroides survived until the early permian. the reticulate veining of l. neuropteroides may have given this species some sort of advantage for survival. during stephanian times, the paralic and paralimnic coal building realms to the north of the variscan range were replaced by fluvial plain conditions with rare, small swamps, where l. neuropteroides, reticulopteris muensteri and barthelopteris germarii were well represented. the effect of a cooling climate from pendeleian to asturian times on reticulation is unclear. still, the cold-resistant paripteris gigantea, neuropteris obliqua and alethopteris spp, occurred in the colder, higher elevation svoge basin, which in the lower elevation basins developed reticulate veining. a shortage of water can arise from low levels of water in the soil or subsoil, and also as a result of seasonal or periodic low air humidity. the study of recent and fossilized plants has established that they have many tools to compensate for insufficient water supply, including the retardation of plant architecture (krassilov, 1972), but vein reticulation has not been discussed. the large size of leaves in glossopteris is regarded as proof of a genuinely tropical (equatorial) climate. the euramerican carboniferous megaflora inhabited warm and temperate zones, but this does not necessarily mean tropical; some use the alternative term pseudotropical. the application of contemporary classifications of floral climatic zones for the geological past is rather arbitrary and lacks clear reasoning. yanaki georgiev tenchov: vein reticulation in seed ferns of the dobrudzha coalfield bulgaria geologia croatica 357 plate 1 1 cardiopteridium waldenburgense sample 05750, drill 56, 1640 m sl -321, rakovski f, pendelian. single connection between veins. 2 paripteris gigantea upper side. sample 06541 lower surface of the sample. drill 73, 1651 m, sl 141, mogilishte f, langsetian. meshes near to midvein. 3 paripteris gigantea upper side. sample 06529 drill 73, 1582 m, sl 210, mogilishte f, langsetian. meshes at left part and near to the midrib. tenchov & popov 1987b, pl. 2, fig. 3. 4 paripteris linguaefolia upper side. sample 15252. drill 179, 1442 m, sl 261, mogilishte f, langsetian. rarer meshes. 5 linopteris neuropteroides upper side. sample 08542. drill 90, 1727 m, sl 381, mogilishte f, langsetian. imperfect reticulation in lower half around midvein. 6 paripteris gigantea upper side. sample 09418 drill 95, 1896 m, sl 386, mogilishte f, langsetian. imperfect reticulation in lower half around midvein. tenchov & popov 1987a, pl. 2, fig. 5. 7 paripteris pseudogigantea upper side. sample 08305 drill 81, 1866 m, sl 668, makedonka f, duckmantian top. partly anastomosed. the scale bars are 1 cm. geologia croatica 65/3geologia croatica 358 the diminishing size of the pinnules is usually viewed as a sign of water shortage, but it is noticeable that many late westphalian pectopterids have relatively large pinnules. also, in swamp conditions, air humidity is not low, especially close to the surface. cooling has a similar effect on pinnule size, as demonstrated in the svoge basin (tenchov, 1976). a decisive dry spell would lead to thicker cuticles, and stomata with a negative relief and neighbouring trichomes. stomatal densities have never been studied in the dobrudzha coalfield. trichomes could sometimes act as water reservoirs. trichomes within the same species, in the same area and level, are dense in some pinnules and not dense in others. the vaulted form of the pinnules probably diminished water consumption. linear pinnule borders are more widespread in the upper levels of the westphalian stage. pinnules with a denticulate or undulating border are much more common in the lower levels of the westphalian, such as seen in pecopteris plumosa, mariopteris acuta, m. muricata, and some eusphenopteris species; these are replaced at a later date by species with more straight-edged pinnules including mariopteris nervosa and pecopteris huchetii. changes in vein density should be evaluated for one and the same species at different stratigraphic levels or in a lineage of species such as alethopteris urophylla – a. densinervosa – a. serlii. the flexuosity of veins can lead to partial or complete reticulation as is the case with neuropteris obliqua – n. semireticulata – reticulopteris munsteri. touching of laterals is realised in some alethopteris species with dense and flexuous lateral veins (pl. 2, fig. 12), but this does not lead to the type of reticulation seen in lonchopteris. the fact that paripteris/linopteris and alethopteris/lonchopteris reticulated simultaneously during early westphalian times points to a common cause – drier conditions. in the dobrudzha coal basin reticulation is even observed in seeds (pl. 2. fig. 12). pinnule shedding is a characteristic only for some neuropteridians. 7. conclusions the composition of bulgarian carboniferous megafloras supports the idea that cooling took place during late carboniferous times (tenchov, 1976, 2011). the cooling is related to a considerable drop in atmospheric co2 (frakes, 1979). after analysing the deposits from the european upper carboniferous, strachov (1960) defined a region of aridity, which extended from britain to lvov-volinsk and lay within the variscan foredeep. many characteristics of the westphalian plants indicate adaptation to drier air. such adaptations can be observed in the pendeleian substage, but are more strongly expressed in several episodes preserved within the westphalian stage. during the namurian, alethopterids started the process of reticulation of veining, resulting in the appearance of lonchopteridium and lonchopteris (fig. 2 – anastomosis – step1). later, towards the end of namurian times and the beginning of the westphalian age, vein reticulation started in paripteris (fig. 2 – anastomosis – step 2), resulting in linopteris. the same happened with neuropteris obliqua about the end of duckmantian times and its transformation into reticulopteris (fig. 2 – anastomosis – step 3-4). this is when the real linopteris first appeared, which were not merely reticulated paripteris. the next step is the appearance of l. bunburii (fig. 2 – anastomosis – step 5) with perfect isometric small vein meshes – about 1 mm in size. in the dobrudzha coalfield, the transition to linopteris and reticulopteris is well-represented by intermediate forms of partial reticulation in paripteris and n. obliqua. the transformation of alethopteris into lonchopteris at about the end of yeadonian times, or the beginning of langsettian times, is poorly represented in the dobrudzha coalfield, but the early appearance of lonchopteris baurii (tenchov, 2004a) demonstrates that this happened in this region too. the occasional vein reticulation around the end of the westphalian age did not lead to new reticulated species or genera. it seems that local linopteris, such as l. subbrongiartii and l. regniezii, appear in other variscan regions. linopteris neuropteroides and reticulopteris outlive many other pteridosperms and become an important element of stephanian and lowermost permian megafloras, when climate aridification became strongly expressed once again. the periodic reduction in rainfall affected large regions. in the dobrudzha coal basin it is reflected in the reduced amount of imported eroded material in the mogilishte formation (sl 0-50, 450-660), with a short intensive break during deposition of the vranino formation (sl 670-870), and a long break at about the end of bolsovian times (sl 12001300). the reduction in rainfall at sl 670-870 also produced strong weathering of sediments to the south of the seltse fault, which is reflected in the quartz sandstones of the velkovo formation. plate 2 8 linopteris sp. sample 13426 drill 160, 1470 m, sl 685, makedonka f, bolsovian. partly anastomosed. tenchov & popov, 1987a, pl. 3, fig. 3 9 alethopteris grandinioides early form. sample 12109 drill 131, 1691 m, sl 731, makedonka f, bolsovian. single touching lateral veins. 10 linopteris sp. sample 14979 drill 173, 1691 m, sl 1149, gurkovo f, asturian. imperfect reticulation. 11 alethopteris densinervosa. sample 11420 drill 107, 1357 m, sl 1242, gurkovo f, cantabrian. single meshes. 12 alethopteris pseudograndinioides var zeilleri. sample 12278 drill 134, 1452 m, 1538 sl gurkovo f, cantabrian. touching lateral veins. 13 reticulated seed most probably of reticulopteris muensteri sample5995, drill 64, 1640 m, sl721, bolsovian. the scale bars are 1 cm. yanaki georgiev tenchov: vein reticulation in seed ferns of the dobrudzha coalfield bulgaria geologia croatica 359 8 9 10 11 12 13 geologia croatica 65/3geologia croatica 360 the dobrudzha region is a place in which new taxa at the rank of species and genus developed during namurianwestphalian times. the reticulation in the veining discussed here was а result of climatе changes. i am far from the opinion that this is a unique area, but it is one where these changes have been clearly recognised. acknowledgement this paper is a contribution to igcp 575 “pennsylvanian terrestrial habitats and biotas of southeastern euramerica”. thanks go to chris cleal and erwin zodrow for discussion on the problem and to the former also for linguistic assistance. references anisimova, o.i. (1979): flora i fitostratigrafia srednego karbona severnogo kavkasa.– naukova dumka. kiev, 107 p. boncheva, i., dimitrova, t. & lakova, i. (1994): konodonti i palinomorfiya ot devonskata i karboniskata sistema v sondajite c-11, p-120 ordajden, severoiztochna bulgariya.– rev. bulg. geol. soc., 55, 55–64. crookall, r. (1959): fossil plants of the carboniferous rocks of great britain (2).– mem. geol. surv. great britain, 4, 2, 85–216. dimitrova, t. (1993): palynostratigraphy of the irecek formation (upper visean – lower namurian) from dobrudzha coal basin, north-east bulgaria.– geol. balcanica, 23/4, 55–63. egemen, r. (1958): on the significance of the flora found in the ihsaniye beds at kozlu, zonguldak.– rev. fac. sc. univ. d`istanbul, ser. b, 24 /1–2, 1–24. frakes, l.a. (1979): climates throughout geologic time.– elsevier, amsterdam, 310 p. gothan, w. (1953): die steinkohlenflora der westlichen paralischen steinkohlemreviere deutschlands. lieferung 5.– beih.geol. jb, 10, 1–83. jordan, m., tomescu, c., antonescu, e., iliescu, v., iva, m., bitoianu, c. & vaida, m. (1987): formation jurassices et paleozoics superieures du forage dobromiru, dobrogea de sud (se de la plate-forme moesienne).– dari de seama, 72– 73/4, 19–44. josten, k.-h. (1962): neuropteris semireticulata eine neue art als bindeglied zwischen den gattungen neuropteris und reticulopteris.– palaeont. z., 36, 33–45. krassilov, v.a. (1972): paleoecologiya nazemnih rastenii.– vladivostok, 212 p. nikolov, z. (1988): geologiya na dobrudzhanskiya vuglishchen basein.– technika, sofia, 171 p. potonié, r. (1910): abbildungen und beschreibungen fossilier pflanzenreste.– lief. viii, 180 p. spassov, ch. & yanev, s. (1966): stratigrafiya na paleozoiskite sedimenti v sondazhite ot severozapadna bulgaria (bulg.).– izvestiya na geol. inst., 15, 25–77. strachov, n.m. (1960): osnovi teorii litogeneza. vol.1. moscow, 212 p. tenchov, y.g. (1976): composition peculiarities of the carboniferous flora of the svoge basin, west bulgaria.– geol. balcanica, 6/1, 3–11. tenchov, y.g. (1993): sedimentation and erosion during the late carboniferous in the dobrudza coal field (north-east bulgaria).– geol. balcanica, 23/2, 3–18. tenchov, y.g. (2004a): the genus lonchopteris brongniart in the dobrudzha carboniferous basin, bulgaria.– geol. balcanica, 34/1–2, 97–104. tenchov, y.g. (2004b): rakovski formation (carboniferous, ne bulgaria) – stratigraphy, sedimentary conditions and interpretation.– geol. balcanica, 34/1–2, 85–96. tenchov, y.g. (2011): peculiarity in the composition of the carboniferous megaflora in svoge and dobrudzha coalfields (bulgaria). – bulletin of the natural history museum, 4, 37–49. tenchov, y.g. & cleal, c.j. (2010): neuralethopteris foliage (medullosales) in the carboniferous of the dobrudzha coalfield, bulgaria.– rev. palaeobot. palynol., 158, 298–307. tenchov, y.g. & popov, a. (1987a): the genus linopteris presl (late carboniferous) in dobrudzha coal basin.– geol. balcanica, 17/1, 15–32. tenchov, y. g. & popov, a. (1987b): the genus paripteris gothan in dobrudzha coal basin (late carboniferous).– geol. balcanica, 17/3, 77–90. tenchov, y.g. & popov, a. (1990): morphogenetic transition between genera neuropteris (brongniart) and reticulopteris (gothan) in dobrudzha coal basin.– geol. balcanica, 20/6, 41–51. zodrow, e.l., tenchov, y.g. & cleal, c.j. (2007): the arborescent linopteris obliqua (medullosales, pennsylvanian).– bulletin of geosciences, 82, 51–84. manuscript received january 11, 2012 revised manuscript accepted october 03, 2012 available online october 30, 2012 1. introduction in the karst region of the republic of croatia, the carbonate rocks are partly characterised by the occurrence of large and small caves. according to the statistical data of gara©i∆ (1991) the “proper caves” form approximately 29% of spelaeological objects, and the remaining of 69% are vertical caves and sinkholes. gara©i∆ (1991 p. 30) also observes that “… horizontal and vertical cave systems are located in the zones of marked tectonic activity …”. polak (1955, p. 66) realised that there must be a causal connection between the fracture systems and formation of horizontal and vertical caves because “… some kind of cavity must already exist in order to enable the chemical action of water …”. fritz et al. (1981) also observed the direct genetic connection between the faults and spelaeological objects. only a few characteristic areas have been analysed structurally in order to prove the tectonic connection with cave formation. however, the variety of spelaeological objects in the karst region of the dinarides indicates the need for wider structural analyses of this region. the dynamics of tectonic modelling of some caves in the karst region (croatia) domagoj jami»i∆ and tomislav novosel 2. results and discussion the studied caves are located on the island of krk, near the maslenica strait and in the paklenica nature reserve, all in the contact zone between the palaeodynamic units of the dinarides (herak, 1986), and also in the zeleni vir area. formation by extensional tectonic processes is characteristic for some caves on krk island, in the region of omiπalj (tenka peninsula). the half-opened caves found there were formed by extensional deformation processes during the pliocene and quaternary (jami»i∆ et al., 1995). the caves are connected to joint systems that were formed under the influence of the nesw regional stress. this happened during the late palaeogene neogene period of tectonic activity, when the cretaceous-eocene sediments were folded into a sequence of parallel linear folds symmetric anticlines and synclines. the fold axes have a nw-se strike, which is the structural characteristic of the dinarides. during reverse faulting and thrust faulting of the cretaceous-eocene limestones, conjugated shear joints were formed that with the long-lasting influence of stress gradually became the sinistral or dextral transcurrent faults. the prevailing faults are of ne-sw strike, and show dextral tectonic transport of the northwestern blocks. the more frequent occurrence of these faults is in connection with a clockwise rotation of the stress of approximately 30°, when the translation of the foraminiferal limestone rock masses also took place. in this phase of kinematic formation of the structural fabric the extensional joint systems were also formed. they are found in the zone perpendicular to the regional fold axes and are limited by transcurrent faults. these joints are almost vertical, closely spaced and with rugged walls (fig. 1), and are frequently encountered in the zones where there is no more than 20-60 cm between the joints. these joints are also present in the flysch deposits, but they are not as frequent. this is explained by the fact that flysch deposits have reduced susceptibility to break caused by their greater ductility index in relation to the cretaceous and eocene limestones which loose their elasticity very early in the deformational process. in the pliocene and quaternary, the structures that formed were influenced by the changed stress regime of approximately n-s orientation geol. croat. 52/2 197 202 13 figs. zagreb 1999 key words: tectonics, stress, caves, compression, extension, karst dinarides. institute of geology, sachsova 2, p.o. box 268, hr-10000 zagreb, croatia. abstract deformational processes resulted in the formation of certain caves in the carbonate rocks of the karst area are analysed. some of the caves were formed by deformational processes connected to extension of the area, while others were formed by processes that followed compression during structural formation of the dinarides. in the first case, the caves were infilled by calcite material and/or by debris from the surrounding rocks mixed with terra rossa. the second group is mostly represented by caves forming open spelaeological objects. 198 geologia croatica 52/2 (ritsema, 1974; del ben et al., 1991). previously formed structures were affected by the newly formed stress field, and were gently folded along the e-w axis. it is around this new axis that the already existing reverse fault planes and regional structural axes of nwse strike were folded. the change in the stress field orientation caused the opening-up of the previously formed fracture systems (fig. 2). the joints and faults were separated that were unfavourably oriented, i.e. the joints that were approximately at right angles to the new stress direction. concurrently with this process, the old structures were uplifted and came under the influence of ground water. the opened fracture systems were then filled in by the impure calcite in the stalactite and stalagmite forms that cemented most of the opened joints. the c1 4 radiometric analysis gave the age of calcite forms of approximately 40 ka. the continuation of opening has been determined at some joints (fig. 3) followed by formation of vertical caves that reach width of up to 2 m on the surface. these opened joints are filled with loose fragments of surrounding cretaceous and foraminiferal limestones mixed with terra rossa. the aforementioned clearly confirms the recent activity of extensional processes. cave formation under the influence of compression is characteristic for the following exploration objects. in the area of the maslenica anticlinal structure (prelogovi∆ et al., 1995), lies a sequence of smaller and some larger caves that were formed during the modelling of this structure. they are more abundant in the southern limb (fig. 4) on the western part of the maslenica asymmetric anticline. in the initial phases of formation of the maslenica structure, the cretaceous limestones were folded into an uplifted anticline of dinaric strike (nw-se). the folding commenced in the late palaeogene under the influence of the regional stress oriented approximately nesw. joints and faults are the main structural characteristics that follow the folding in this phase of structural formation. a set of fracture systems and fold elements show a symmetric arrangement that suggests that the fractures formed as a direct consequence of folding influenced by a ne-sw directed contraction of the area and its nw-se extension. along with compression of the area and continuation of deformational processes, tectonic transport occurred on the bedding planes towards the crestal part of anticline. this transport is documented by preserved striation marks that are found on the bedding planes. the azimuth of the greatest principal stress axis (σ1 ) based on direct measurements of the striation marks lies in the range of 30-60°. a set of conjugated joints simultaneously formed that would be transformed into sinistral and dextral transcurrent faults in later phases of structural development. an important role in the final shaping of the maslenica structure was played by nesw oriented joint systems, i.e. the joints perpendicularly oriented to the regional b axis. in the later phase of deformation, the novsko ædrilo strait was formed by subsidence of tectonic blocks along these joints that are encountered at distance of approximately 20-30 m apart. the kinematic act of folding was accompanied by the formation of fracture systems parallel to the regionfig. 1 the closed fracture system of the zone perpendicular to the structure axis (tenka peninsula, omiπalj, island of krk). fig. 2 separate fracture systems filled by calcite material. formation of a half-opened cave (tenka peninsula, omiπalj, island of krk). fig. 3 the cave filled by terra rossa and rock fragments (tenka peninsula, omiπalj, island of krk). al b axis; in other words the joints pertaining to the axial plane cleavage zone were formed. these joints have a sigmoidal bend and never crosstransect the bedding planes. the caves were opened by brecciation of rocks at intersections of these discontinuity surfaces with the bedding planes (figs. 5 and 6). the longitudinal axes of caves follow the regional axis of the maslenica structure. the caves were, during the quaternary, mostly filled with deluvial-proluvial deposits, and some remained opened. in most of the caves, stalactites and stalagmites occur, some of them up to 3 m in thickness (fig. 7), which indicates that the relaxation phase started after the maslenica structure was uplifted to the level of ground water influence. with formation of the new regional stress field, oriented n-s, the maslenica structure experienced new tectonic changes during the pliocene and quaternary. the change in orientation of stress caused a gentle bending of the structure around a vertical axis in such a way that its eastern parts rotated counter-clockwise for some 40°. the n-s oriented compression also resulted in the folding of the northern limb of the anticline around a horizontal axis oriented e-w. in consequence, this limb became more inclined thus making the anticline asymmetrical, with the axial plane vergence towards the n-ne. the steepening up of the anticlines northern limb was, in the southern-southwestern limb followed by reverse faulting and displacement of the hanging wall blocks in n-ne direction (fig. 8a). the reverse faults cut through all the previously formed structural elements. the presumption that these deformation processes are very recent was confirmed by observations made on the quaternary sediments filling one of the caves, which also has stalactite and stalagmite build-ups. the quaternary deposits are foliated parallel to the reverse fault planes, and the stalactites are cut and displaced in lengths of 11 cm (fig. 8b) along the joints parallel to the reverse fault. the age of stalactite formation was determined by c1 4 r a d i o m e t r i c dating to be approximately 36 ka, which implies that deformational processes must have been even younger. these faults do not exhibit big relative displacements. based on the direct measurements of the linear elements they are in the range of 3-11 cm. the reverse faulting on the southern limb of the maslenica structure was immediately followed by extensional processes conditioned by rotation of its eastern part. these processes are also recently active, which has been ascertained by the finding of the recent gastropods helix pullmonata fossilised in the material that filled one of the previously opened joints (fig. 9). this joint, 80 cm wide, belongs to the older deforma199jamiëiê & novosel: the dynamics of tectonic modelling of some caves... fig. 4 the formation of caves on the maslenica structure, along intersections of the bedding planes with the sigmoidal joints of the axial plane cleavage zone. fig. 5 minor caves on the southern limb of the maslenica anticline (western bank of the novsko ædrilo channel). fig. 6 the cave formed on the intersection of a bedding plane with sigmoidal joints of the axial plane zone (detail of fig. 5). 200 geologia croatica 52/2 tional phase system, and is filled by fragments of surrounding rocks mixed with terra rossa. another cave formed by compressional deformation processes is in the paklenica natural reserve, where several caves with almost horizontal entrances are found. one of them, illustrated in fig. 10, is also located in the cretaceous limestones that were exposed to strong tectonic deformation in the course of folding and structural formation of this part of mt velebit. the cave is genetically related to the zone of extensive crushing of limestones between the two semi-parallel reverse faults positioned 270/46°. the fault planes are at a distance of little bit more than 2 m, and it is in this space that the relatively closely-spaced sigmoidal fracture systems were developed during the displacement on the fault planes. these sigmoidal fracture systems increased the brecciation of rocks and made it possible for certain separate blocks to become loose. the reverse displacement is defined by the linear striation marks with a sinistral angle of 75° on the fault planes (fig. 11) and by the sigmoidal shapes of joints between the faults. the calculated azimuth of stress (σ1 = 259/5°), that conditioned the formation of structures lies along the e-w axis, with a vergence of structures in an eastern direction. a similar tectonically induced situation of cave formation is encountered in the vicinity of the entrance to the newly discovered slovakia cave (fig. 12) in the roæanski kukovi area of the central part of mt. velebit. it is also here, like in the case of the paklenica cave, that several parallel reverse faults are observed. they have a 50° dip and satellite sigmoidal fracture systems. the slovakia cave “… has an atypical, horizontal entrance that mostly resembles a cave, rather than a vertical hole.” (kozar»anin et al., 1996). according to the personal communication of d. bak©i∆, one of the cave explorers, the reverse faults have a dinaric strike, i.e. nw-se. the fracture systems that led to opening of this caves entrance are surely connected with strong comfig. 7 the cave on the northern limb of the maslenica structure. the broken stalactite is approximately 3 m in diameter. fig. 8 a) the sigmoidal joint systems formed by reverse displacement on bedding planes. b) the stalagmite intersected by a reverse fault (eastern side of the novsko ædrilo strait). a b 201jamiëiê & novosel: the dynamics of tectonic modelling of some caves... pression of the area, and influenced by the greater deformation index of the jelar deposits, not only by their reverse faulting. according to the same explorer (d. bak©i∆) the cave has some 10-15 meters of horizontal length, and after a few steps it passes into a vertical hole of the slovakia cave. this information points to the existence of transcurrent faults that are normally connected to this kind of structural formation in the course of strong folding in an area. another example of a studied spelaeological object that can be interpreted to have been conditioned by tectonic events is the muæeva hiæa cave. the cave (fig. 13) is located on the right bank of the curak brook, in the end of the vraæji prolaz canyon that is in the immediate vicinity of the zeleni vir near skrad. in contrast to the two previously described spelaeological objects, the muæeva hiæa cave was formed by structural deformation between the bedding planes that occurred during the folding and reverse faulting of jurassic limestones. it was formed by tectonic processes comparable to those observed at the maslenica structure. namely, the reverse displacement along the bedding planes formed relatively closely spaced joint systems of the axial plane zone, that have with development of deformational processes obtained sigmoidal shapes. the narrowing of joints close to their contact with bedding planes caused a stronger fragmentation of rock and thus enabled cave formation. the cave was formed in the lower part of the arch-shaped sigmoidal joint systems, rather then in their upper part. this is due to the fact that in this zone the blocks are more easily separated under the influence of gravity, thus making the place for the next blocks to fall out. the approximately 40 m long cave has a dinaric strike which implies that the structural elements that caused its forfig. 9 detail of the cave filled by crystallised calcite material and quaternary deposits with fossilized gastropod helix pullmonata. fig. 10 the closed entrance to the cave in the paklenica natural reserve. fig. 11 linear striation marks on a reverse fault. detail of fig. 10. 202 geologia croatica 52/2 mation also belong to the time of structural formation of the dinarides. 3. conclusion the presented data draw the conclusion that the studied shapes of some caves within the carbonate rocks of the part of dinarides were modelled by different tectonic processes. some of them were connected with extension of the area, while other were found to result from the compressional activity during the folding in the phases of strong structural reorganisation of the dinarides. in the younger phase of tectonic activity, the extensional processes led mostly to opening of the previously formed fracture systems. the calcite build-ups were sedimented in these joints, and they were later filled with fragments of the surrounding rocks and terra rossa. the caves that can be interpreted to have been formed due to compression of the area are more abundant in the carbonate rocks of the dinaride area. they were formed either by rock fragmentation taking place at intersections between the reverse fault planes and the satellite joint systems, or by the reverse displacement along the bedding planes followed by the occurrence of closely-spaced sigmoidal joints of the axial plane zone. 4. references del ben, a., finetti, i., rebez, a. & slejko, d. (1991): seismicity and seismotectonics at the alps-dinarides contact.boll. di geofis. teor. ed app., 33/130-131, 155-175, trieste. gara©i∆, m. (1991): morphological and hidrogeological classification of speleological structures (caves and pits) in the croatia karst area.geol. vjesnik, 44, 289-300. herak, m. (1986): a new concept of geotectonics of the dinarides.acta geologica, 16, 1-42, zagreb. fritz, f., boæi»evi∆, s., pavi»i∆, a. (1981): rasjedi i pojava speleoloπkog sistema.naπ krπ, 10-11, 47-53, sarajevo. jami»i∆, d., prelogovi∆, e., tomljenovi∆, b. (1995): folding and deformational style in overthrust structures on krk island (croatia).in: rossmanith, h.-p. (ed.): mechanics of jointed and faulted rock. 359-362, balkema, rotterdam-brookfield. kozar»anin, i., sutlovi∆, a. & bak©i∆, d. (1996): slovakia joπ jedna kilometarska jama.veëernji list, 9. 8. 1996., zagreb. polak, k. (1955): tektonski pokreti i postanak peêina.speleolog, 3-4, 65-68, zagreb. prelogovi∆, e., jami»i∆, d. & novosel, t. (1995): the dynamic of joint and fault modelling in carbonate rocks maslenica structure (croatia).in: rossmanith, h.-p. (ed.): mechanics of jointed and faulted rock. 355-358, balkema, rotterdambrokfield. ritsema, a.r. (1974): the earthquake mechanism of the balkan region.undp project r. 3 em, 70/ 172, unesco, skopje. manuscript received february 19, 1999. revised manuscript accepted november 12, 1999. fig. 12 the slovakia cave entrance (photograph taken by d. bakπiê). fig. 13 the muæeva hiæa cave in the vraæji prolaz canyon (zeleni vir). geolog la croatica 45 185 -186 zagreb 1992 . ozren lukić (1965 1992) braneći velebit 14. srpnja 1992. poginuo je diplomirani inženjer geologije ozren lukić, dobrovoljac i časnik hrvatske vojske. pokopan je na mirogoju u prisutnosti rodbine, prijatelja, brojnih kolega i suboraca. od pokojnika su se oprostili u ime planinske satnije velebit njen zapovjednik jerko kirigin, a u ime instituta za geološka istraživanja dr. srećko božičević. izraze poštovanja i zahvalnosti mještana starigradapaklenica i selina izrazio je župnik don tomislav baričević. nad grobom od pokojnika se oprostio mr. tihomir marjanac u ime članova speleološkog odsjeka hrvatskog planinarskog društva "željezničar". institut za geološka istraživanja priredio je 23. srpnja 1992. komemoraciju u spomen svog djelatnika na kojoj su sjećanja na ozrena lukića evocirali dr. božidar biondić i dipl.ing. mladen kuhta. ing. ozren lukić rođenje 24. veljače 1965. u zagrebu gdje je završio osnovnu i srednju školu. nakon odsluženja vojnog roka 1984. pohađa studij geologije na rudarsko­ geološko-naftnom fakultetu sveučilišta u zagrebu. diplomski rad pod nazivom "geologija i geneza speleoloških objekata područja nacionalnog parka krka", obranio je 15. svibnja 1990 s odličnim uspjehom. tijekom studija, dijelom zbog materijalnog osiguranja rano zasnovane obitelji, ali još više potaknut željom za što bržim i boljim stjecanjem stručnih znanja, od 1983. radi kao vanjski suradnik instituta za geološka istraživanja, a od 1988. i na hrvatskom prirodoslovom muzeju. zahvaljujući iskazanoj marljivosti primljen je na rad u institutu za geološka istraživanja u veljači 1991. godine. vrlo brzo došla su do izražaja sva ranije stečena znanja i iskustva. posebno je značajan njegov doprinos u formi;anju katastra speleoloških objekata u sklopu projekta izrade osnovne hidrogeološke karte republike hrvatske u mjerilu 1:100.000. s njim popunjena postojeća speleološka ekipa našeg instituta mogla je obavljati sve terenske i kabinetske radove. počele su se rađati nove ideje i odlasci na nove terene, pa se tako prikupljala i dokumentacija potrebna za upis njegovog postdiplomskog studija ... no tada je došla turobna jesen 1991. i nametnut nam rat. tamni oblaci zla nadvijeni nad našu hrvatsku bacili su sjenu i na njegov uvijek nasmješen lik. nasuprot mračnim silama stala je iskrenost i ljudskost, nasuprot topova i aviona diglo se njegovo srce. sve njegove profesionalne preokupacije preusmjerene su dobrovoljnim pristupanjem postrojbama hrvatske vojske, koncem rujna 199 l godine. speleološka aktivnost dipl.ing. ozrena lukića rezultat je njegovog istinskog istraživačkog duha i to se najbolje potvrdilo u našem krškom podzemlju. emotivni doživljaj prvog susreta s vječnom tamom zemljine dubine najbolje oslikava zabilješka u dnevniku, kada je nakon posjete spilji vetemici zapisao: "našao sam najljepše mjesto na svijetu". sve ono što je kao dječak osjećao prema speleološkim istraživanjima, sav zanos i ushićenost, svu radost pri otkrivanju novog i nepoznatog, zadržao je do svog posljednjeg istraživanja. ostao je dosljedan sebi i speleologiji. članom speleološko g odsjeka planinarskog društva "željezničar" postao je 1979. godine. u proljeće 1980. završava zagrebačku speleološko školu, a 1985. polaže ispit i stječe zvanje speleolog. nalazio se pred završetkom studija za instruktora speleologije, ali je tu smrt bila brža. tijekom posljednjih 13 godina provedenih u speleolo giji sudjelovao je na preko 500 akcija, te je stekao vrhunska znanja i rutinu u tehnici istraživanja. bio je vrstan organizator i vođa nekoliko klubskih, republičkih i saveznih speleoloških istraživanja i ljetnih logora, uglavnom na području velebita. obišao je gotovo sve velike speleološke objekte u hrvatskoj, a od najznačajnijih istraživanja valja spomenuti istraživanja jama m~mdelaje (-120 m, duž. 2326 m), sustava kicljeve jame (-285 m, duž. 1075), klementine i (-269 m, duž. 2403), klementine iii (-333 m), klementine iv (-300), burinke (-290 m), stare škole (-576 m) i munižabe (-448 m, duž. 2300 m), te spilje vetemice (duž. 6654 m). izniman je njegov doprinos kao suradnika u speleološkim i hidrogeološkim istraživanjima provedenim za potrebe projektiranja i izgradnje hidroenergetskih i drugih objekata na području krša hrvatske kao i pri regionalnim 186 speleološkim istraživanjima žumberka, nacionalnog parka krka, te područja uz rijeke dobru i koranu. već kao mlad speleolog sudjelovao je na i hrvatskoj speleološko j ekspediciji 1982. godine u jamu gouffre berger (francuska) duboku 1242 metra, te kasnije i na iii hrvatskoj speleološko j ekspediciji "picos de europa" u spanjolskoj 1986. njegova neograničena radna energija, entuzijazam ali i organizacijske sposobnosti najbolje su se očitovale u radu speleološko g odsjeka pd "željezničar". na mjesto pročelnika on je izabran 1986. godine i od tada do posljednjeg dana neumorno je radio na "tisuću" poslova i sitnica koje su omogućile rad, opstojnost i razvoj jedne amaterske organizacije u ovako teškim vremenima. prve ozbiljne iskorake u svijet znanstveno-stručnih aktivnosti realizirali smo zahvaljujući ponajviše njegovom trudu. speleološki klub stručno znanstvena i istraživačka organizacija njegovo je djelo, pa je razumljivo, da je upravo on bio i njegov prvi predsjednik. jedna od najznačajnijih crta njegove osobnosti bila je izuzetna upornost. u 1983. preuzeo je poslove arhivara speleološkog odsjeka. godinama je neumorno obrađivao gomilu nesređenih zapisa, skica i nacrta da bi na kraju bio stvoren potpuno kompjuteriziran speleološki katastar s podacima o preko 2000 spel. objekata istraživanih u razdoblju od proteklih pedesetak godina. sva svoja znanja i iskustvo onje neumorno prenosiđ na mlade članove speleološke organizacije sudjelujući u radu mnogobrojnih speleoloških škola, tečajeva i seminara te organizirajući predavanja iz područi-> speleo logije. sudjelovao je u radu osmog speleološkog kongresa na borskom jezeru 1980. i desetog kongresa speleologa u sarajevu !988., a iste godine bio je i sudionik devetog svjetskog kongresa speleologa u barceloni. za svoj rad na području speleologije dodijeljena su mu priznanja pd "željezničar" 1985. i so pd "mosor" iz splita 1988. godine. planinarski savez zagreba dodjelio mu je srebrni znak 1989., a srebrnim znakom planinarskog saveza hrvatske odlikovan je 1990. godine. i kada je dolazio s velebitskog ratnog područja na zaslužen kratak odmor u zagreb njje zaboravio na započete radne zadatke u institutu. ostajući i poslije radnog vremena uredno bi pripremio dijelove izvještaja i ostavio ih za daljnju obradu. čak i zadnja istražena jama na velebitujama na pločama oko badnjaostala je uredno zabilježena i obrađena u njegovim bilješkama u institutu. moramo priznati, da smo se na njegovu savjesnost i mirnoću pri viknuli mnogi u institutu, tako daje i njegov nenadani odlazak ostao samo zatomljen tugom i saznanjem da smo izgubili istinski marljivog i za sve nas neprežaljenog suradnika, kolegu i prijatelja. geologia croatica 45 za sve što je učinio u svom i ovako kratkom životu iskrena mu hvala i vječna slava! mladen kuhta bibliografija ozrena lukića: l. istraživanja zagorske peći kod ogulina. -naše planine, 1-2, 38, zagreb, 1983. 2. istraživanja mandelaje.naše planine, 7-8, 181-182, zagreb, 1983. 3. kronološki pregled istraživanja mandela je. spil j arski vjesnik, 2, 7-8, split, 1983. 4. nova istraživanja u mandelaji.naše planine, 1-2, 34, zagreb, 1984. 5. ronjenje u pećini zali.naše planine, 1-2, 29-30, zagreb, 1986. 6. još jedan sifon.naše planine, 1-2,30, zagreb, 1986. 7. sustav kicljeve jame.naše planine, 5-6, 103-105, zagreb, 1986. 8. iza sifona u mandela ji.naše planine, 3-4,93, zagreb, 1987. 9. sustav kicljeve jame.speleolog, 32-33,28-31, zagreb, 1987. 10. još jedan sifon.speleolog, 32-33,61, zagreb, 1987. ll. spiljarski vjesnik.speleolog, 32-33, 67,zagreb, 1987. 12. jama burinka na crnopcu u velebitu.naše planine, 9-10, 230-232, zagreb, 1988. 13. speleološki objekti okolice prezida u gorskom kotaru. -speleolog, 34-35,29-31, zagreb, 1989. 14. priroda. -speleolog, 34-35, 61, zagreb, 1989. 15. speleološki adresar.speleolog, 34-35, 61, zagreb, 1989. 16. jama burinka na crnopcu u velebitu. -speleo bilten, l, 22-24, karlovac, 1989. 17. minižaba u crnopcu na velebitu. -naše planine, 1112, 275-276, zagreb, 1989. 18. demant.velebiten, 4, 19-20, zagreb, 1991. 19. & hudec, svjetlan: preliminarna speleološka istraživanja područje rijeke korane za potrebe gradnje he lučica.speleolog, 36-37, 41-47, zagreb, 1991. 20. & hudec, svjetlan: preliminarna speleološka istraživanja područja rijeke dobre za potrebe gradnje he lešće.speleolog, 36-37,48-52,zagreb, 1991. 21. speleološka istraživanja crnopca na velebitu. -speleolog, 36-37, 14-26, zagreb, 1991. 22. -,gabrić, goran & klarić, željko: jama stara škola na biokovu (~576 m). speleolog, 36-37, 27-33, zagreb, 1991. geologia croatica 45 151162 6 pig. zagreb 1992 udc 551.248.2:551.79(497.13) scientific paper correlation of quaternary sediments and tectonic activity of the eastern part of the drava river depression eduard prelogović and josipa velić key-words: the drava river depression, correlation of the quaternary deposits,lake and swamp sedimentation, quatemary tectonic activity, boundary depression faults, diagonal fa ul t system, vertical and horizontal movements the holocene, upper pleistocene and middle pleistocene sedi­ ments in the eastern part of the drava depression the su bstratum of which is determined by the conditional ek marker q', are composed in the lower part mainly of silts and clays and in the upper part of sands. the thickest parts are about 400m. the composition of the transparent heavy minerals and the result of the paleontological treatment show that the sedimentation was in the lake or swamp with the ori­ gin of detritus from the metamorphic rocks and smaller quantity of older clastic sediments. the collected data show the quaternary tectonic activity after the sedimentation of the marker horizon q'. in the area between the boundary faults of the valley, the faults of the system e.n.e. w.s.w. (n.e. s.w.) influenced directly the sedimentation and the folding . they were the consequence of the regional movements and stress strain behaviour of rock masses, which built the structures of the valley. as a result, the horizontal component of the left wing movement is visible along the diagonal system of faults. the vertical movements have also been determined. the greatest amplitudes were along the boundary south fa ul t of the drava valley, up to 350m for the period of middle and upper pleistocene, or 90m for upper pleistocene only. l. introduction in the research work on the quatemary sediments of the pannonian basin the attention is most frequently paid to the composition of the sedim en ts especially for the geological mapping, hydrogeological, engineering geological and the climate problems, as well as to the chronostratigraphic and sedimentary classifications. little is known about the presence of the tectonic movements, their amplitudes and their influence on the sedimentary and structural changes. it was possible to get more information about their characteristics in the investi­ gated area based on the new data concerning the drilling, geophysical profiling and the correlation of the sedi­ ments. data obtained in the last ten years in the hydrogeological and petroleum geological explorations and geological mapping were available. increasing research has been done on the quaternary sediments in order to obtain more data for the building of the hydro-electric po wer plant on the river drava. the new interpretation of the seismic cross section up to the depth of 600 m and the ključne riječi: dravska poto lina, korelacija kvartarnih naslaga, jezersko-močvarna sedimentacija, kvartarna tektonska aktivnost, rubni potolinski rasjedi, dijagonalni sustav holocenske, gornjopleistocenske i srednjopleistocenske taložine istočnog dijela dravske potoline podinu kojih označava uvjetni ek reper q', izgrađuju u nižem dijelu poglavito prah i glina, a u višem pij es ci. najveći iznosi debljina su oko 400m. sastav prozirnih teških minerala i rezultati paleontološke obrade ukazuju da se sedimentacija gotovo kontinuirano odvijala u jezeru, odnosno močvari, s porijeklom detritusa iz metamorfnih stijena, podređeno starijih klastita. prikupljeni podaci ukazuju na kvartarnu tektonsku aktivnost nakon taloženja repernog horizonta q' . u prostoru između rubnih ras jeda potoline, na sedimentaciju i boran je izravno su utjecali ras jedi sustava isi zjz (sl jz). oni su posljedica regionalnih pokreta i pomaka masa stijena koje izgrađuju strukture rubnih dijelova potoline. zbog toga se duž dijagonalnog sustava rasjeda razabire horizontalna komponenta lijevog pomaka. ustanovljeni su i vertikalni pomaci. najveće amplitude su duž južnog rubnog ras jeda dravske potoline do 350m za razdoblje srednji i gornji pleistocen, odnosno 90m samo za gornji pleistocen. shallow cross section obtained by the use of resistivity methods up to the approximate depth of 250 m was made. the correlation among 45 boreholes was made and the marker horizons (pig. l) were separated. also, new cross sections were obtained by the use of resistivity methods and new boreholes were made, too. it was possible to perform the paleontologic, sedimentary and x-ray determinations of the core materials and the corresponding geophysical measurements in the boreholes. the quaternary sediments have selectively been well known from the former research works, especially their young er part. from the stratigraphical and neotectonic -structural point of view, the most important published works have been separated. they deal with the sedi­ mentary facies analysis, paleontological treatment of the borehole samples of the waterbearing horizons (e. g. babić et al., 1978; kranjec et al., 1971; malez, 1973; sokač,1976; sokačetal.,1982; urumović, 1982; urumović et al., 1976). for better under­ standing of the relation between the quatemary sediments and the older ones and the position of the explored area faculty of mining, geology and petroleum engineering, pierottijeva 6, 41000 zagreb, croatia. rudarsko-geološko-naftni fakultet sveučilišta u zagrebu, pierottijeva 6, 41000 zagreb, republika hrvatska vl '<t .g 8 u .. 'ob o o " o n vl ~ 84 la al 2 ~3 o 10 20km bedee' l ~ ~ fig. l . map of location of investigation works. legend: l resistivity crosssections; 2seismic cross-sections; 3 welllogs cross-correlation ii' and a part of seismic cross-secton ii-ii' of surroundings of kapelna; 4boreholes. slika l. karta lokacija istraživačkih radova. legenda: l geoelektrični profili; 2 -seizmički profili; 3 korelacijski profil i c:io seizmičkog profila okolice kapelne; 4 bušotine. ii 156° 177° t7r 170° 164° 174° 164° t7r (ml f-~ f---l-~ 1----f----~ 100, b-3 dz-4 dd-3 op-8 pz-1 pz-1 pb-6 op-4 l l l l l l l l l l l t l l ! l t l l ! l _.,...,..._____ ' ! so o { t":l i' --·-so -1 2 c§:] 3 o 5 10km -100 fig. 2. welllogs cross correlation i-i'. legend: l penneable layers : sand, gravel; 2unpenneable layers: silt, clay; 3 ek marker. 215° tbr 1--1--0p-3 očp-1 vlp-1 ~~~f7 ~ / // 0' / slika 2. shematski korelacijski profil ii-ii'. legenda: l propusne taložine : pijesak, šljunak; 2nepropusne taložine: silt, glina; 3 ek reper. ii' ~ ~ <j: ~ w 3 z <::> uj :x:: u o ~ 1(/)w~ iiizt..u -iwi...j a.. ue ovt 0::-iq:j wo~ a..::x::­ a.. .... :::> ~ o q:: z <::> <j: i..:j w -1 o o s: § ~ v) z w~ g~ ~-e !!2!:(! wl..u _.1-.1 a.. cl o::w~ 3;<::> g<::> '"" il ~ ~-o. fl:> <! ~ (), (l o ~ ~ s· ::l o .... 10 ; ~ "' -< en " cl. §" " f .... u\ vl 154 in the regional structural complex, the attention is paid to relatively recent papers (e. g. pletikapić et al., 1964; kranjec & prelogović, 1974; herni1z, 1981; prelogović & cvijanović, 1983; jamičić, 1988; royden & horvath, 1988) and to the in­ terpretation of the basic geological map. taking a closer look into literature and adding up new data, the new facies and the marker horizons have been separated. the thickness of the sediments as well as the influences of the tectonic movements have been determined. 2. composition, thickness and correlation of the sediments quatemary sediments on the surface have been well studied and divided in the basic geological map (galović and marković, 1979, galović et al., 1981; hećimović, 1985, 1986; jamčić & brkić, 1986; jamčić at al., 1987; korolija & jamčić, 1988, 1989; marković, 1986, 1986a; magas, 1987, 1987a). from the data defined on the surface as well as in the depression, the boundary pliocene quatemary has not been exactly determined . on the slo pes of the mountains of krndija, papuk and bilogora the exchange of fluviolacustrine gravels, sands and some clays has been determined in the period of p li ocene quaternary. from the sediments which appear on the surface, mainly sands of the aquatic environment and the genetic types of the eolian series have been placed in pleistocene, and the sediments of the fluvial, eolian, marsh and slopewash material facies into holocene. because of the specific characteristics the loess has been studi~",d in detail (e.g. mutić, 1975; bognar, 1990). in the last twenty years, inside the quaternary sediments in the depression of the river drava, a few conditional marker horizons have been observed. one of them is q', which can be determined rather clearly, simple and unambiguous on the lo gs (fig. 2). its position is such, that it divides the quaternary sediments in two parts on the base of the electrophysical and lithologic characteristics. undemeath q' there are sediments from lower pleistocene eventually pliocenepleistocene and above them there are the middle pleistocene, upper pleistocene and holocene sediments (urumović et. al., 1976; herni1z, 1981). these younger sediments are called "wasting cover". their characteristics are the low grade of diagenesis, greater permeability and considerable substance of the coarse-grained clastic sediments gravels and sands. that is why they are presented on the logs by the increased and jumping amplit..udes (erratic). beneath the conditional marker q', there is almost regularly the layer of clay, and the curves do not show jumpy and increased deflections. the characteristic cross-section of the borehole valpovo l (fig. 3) has been chosen for the description of the sediments above the marker q'. the logs from this borehole have a very good vertical resolution which reflects the lithology very authentically and reliably. the overlaying deposits of the marker q' consist of geologia croatica 45 (m) 100 so o ·50 sp lt valp -1 ra 9 8 7 ~3 fig. 3. valp-1 : typical well lo gs of deposits above the marker q'. legend: l • sand; 2 • silt and clay; 3 · ek-marker. slika 3. v alp-1 : tipični dijagram geofizičkih mjerenja u bušotini za naslage iznad re pera q'. legenda: l pijesak; 2 silt i glina; 3 ek-reper. following layers from bottom to top: 27.5 m thick sandy layer with more or less uniform composition; silt 2.5 m thick; ll m thick layer of sand which becomes gradually upwards more and more fine-grained with more silt, and with some clay; 16 m thick layer of silt with some clay interbeds; -sand 36.5 m thick with the strict lower boundary, while in the upper part it shows gradual decreasing of the grains size; in the lower part there arc two interbeds or lenses of silts: 16.5 m thick fine-grained intervalsilts and clays; o 10 20 km !w • ~3 ~j . t,o~>-~o,. ~fl 2 t::__:~ \ \ 1 . 1' čađavica beničanci bizovac 11z• o l l l l l ----o fr···· ·:.;.;.;.;.;.;.;.;.;.;.;.:;:;:;:·;.;.;.;.;.·.·.·~·.:.::,;;:~·-::,:,.:.·.·.: ..... ·.;.;.:;:;::;:::a~:-:8:·:·:·;············~···::::::;:;:;:;:;~:;::::::·:·:·:·::;;:::p•::z:;;ola····l ·-·:: .... ····~:~gg (ml fig. 4. map of thickness of middle and upper pleistocene and holocene sediments. legend: l • isopach; 2 ·cross-section i-i'. sl ika 4. karta debljina srednjo-i gomjopleistocenskih te holocenskih naslaga. legenda: l • izopahe; 2 • profil i-i'. '1:1 n i ~ ;;; fl;o < g. ;;; n o a ~0 o o ..... /0 e ; 3 .. -< ~ §' s r -"' "' l l v> 'v "' ·~ "' o ... u "' 'bh o o " o \c) v> ~, 1~1 4 82 b s • 83 o 10 20km head fa' l fig. 5. map of faults . legend: l -northern boundary fault of the drava depression (l) and southern boundary fault of the drava depression (2); 2faults with downthrown block indicated; 3 reverse faults; 4 faults with strike-slip designation; 5 faults without designated character. slika 5. karta rasjeda. legenda: l sjeverni rubni ras jed dravske depresije (l) i južni rubni ras jed dravske depresije (2); 2 ras jedi s naznakom spuštenog krila; 3 reversni ras jedi; 4 rasjedi s horizontalnim pomakom krila; 5 rasjedi neodređenog karaktera. \ \\ prelogović & velić : correlation of quaternary sediments ... i 20 ~ profil 1j 25 30 --lm) ,~ -168___..j-258fig. 6. seismic cross-section i-i' showing reflection of faults. slika 6. odraz rasjeda na seizmičkom profilu i-i'. uniform sand with the thickness of 17 m; 10 m of sand with silts and humus on the surface. further details concerning the lithology and age, have been obtained with two core drilling boreholes, 100 m deep, placed about l o km west from the town of osijek, on the right bank of the river drava (dz 4, dd 3a, fig. 2). the sediments have been determined by the field classification and the samples have been taken for the laboratory analysis. in the boreholes performed geo­ physical measurements included radioactivity logs. sands, silts and clays are interchanged up to the depth of 100 m. the sands prevail in the upper 50 m, with all the fractions of the grain size, from the fine-grained to the coarse-grained anes. they are mainly ash-coloured with the thin interbeds of brown-grey, yellow-grey and green-grey colour. on some places there are greater quantities of silts which appear in the form of lenses, and have black or dark brown colour, with a lot of carbonaceous organic matter. coarser paleofloristic remains and lignite have also been observed. in the lower part of the geologic column there are more fine-grained clastic materials silts and clays. the colours are grey-greenish, greenish, dark grey, dark brown and bluish grey. these layers almost regularly contain concretions of several mm up to several cm in diameter and the fossil fauna and flora: ostracodes, micromollusca, charophyte oogcinia and phytoproducts. the layers of silts are laminated, which can be quickly and easily observed because of the millimetric exchange of the white and dark grey laminas. the mineral composition of light and heavy fraction of the sand samples is generally uniform along the whole interval of 100 m. in the composition of the light fraction quartz dqminates in the range of 54 76 %. feldspars (1022 %) and the rock fragments (616 %) follow, 35 157 i' l profil j-j 40 45 +sp -----------while the rest to 100 % refers to muscovite. among the transparent heavy minerals the garnet grains pre­ vait, in the range from 42 77 %, and the minerals of the epidote zoisite association (8 10 %) and the amphiboles (823 %) are present. the other miner­ als are present with only few percent; these are pyroxene, dis th ene, staurolite, tourmaline and apatite. s u ch composition points to a certain reconstruction of the paleogeographic relief (mutić, 1989), which be­ comes of a high-grade in combination with the results of micropaleontological treatment (sokač, 1976). the conclusion is that the sedimentation happened in the aquatic environments in the lake, occasionally in the swamp with the presence of vegetation. it would be justified to point to the possibility of periodical evaporation. the origin of detritus is from metamor­ phic rocks, not so often clastic sediments and very rare igneous rocks. from the structural point of view it was very important to determine the thickness of the deposits above the marker horizon q'. it was done in detail, thanks to the net of cross-sections obtained by the use of seismic and re­ sistivity methods and rather convenient scheme of the boreholes. taken globally, the depression of the river drava has a general direction n.w. to s.e. (w.n.w.­ e.s.e.). the neogene deposits show the assimmetry of the depression. the main axis goes alongside krndija and bilogora m ts., and from the town of podravska slatina it goes towards west, directly alongside the zone of the south fault of the river drava valley. the quaternary deposits follow the basic structural elements of the depression only partially. two facts are surprising. first, the deposits in the greater part of the depression are thicker than 200 m, on some parts they are over 300 m, and between the villages kapelna and mikleuš they 158 are over 100 m (fig. 4). second, the deposits aie folded and faulted diagonally to the strike ofttte depression (fig. 4 and 5). there are zones of thicker deposits south from the village of bizovac, east from the town of valpovo, s.w. from kapelna and particularly from the town of don ji miholjac, as well as parallel to the mountain bilogora in the direction from mikleuš to the west. there are also zones of thinner deposits, around the villages of beničanci, bizovac and ćepin and the towns of valpovo and osijek and east from the town of našice. the increasing enlargements of the deposit thickness point to the existance of the faults. speaking of faults, the following facts must be stressed: the deposits are thicker or become thicker by tear and step faults along the boundary faults of ihe valley and also along the fault system e.n.e.w.s.w. (n.e. s.w.); . the diagonal system represents subvertical faults with vertical and horizontal movements; they are synsedimentary faults and they have direct influence on the changes of the composition and the thickness of the deposits; -this influence is visible specially between the faults that stretch by donji miholjac and ćepin; quatemary deposits are crossed by the faults presented in fig. 5; according to the geomorphologi­ cal characteristics of the relief (hećimović & prelogović, 1987) and on the grounds of the sattelite scans analysis the routes of the boundary south fault of the drava valley, partially of the boundary north fault of the drava valley and the diagonal faults stretching alongside donji miholjac, kapelna, beničanci, bizovac and ćepin (in fact parts of the changes in lhe increase of thicknes, presented in fig. 4) are marked specially on the suface. to illustrate the existence of fault systems e.n.e. w.s.w. (n.e.s.w.) fig. 6 shows a part of the seismic cross-section of the area of kapelna. on the correla­ tion profile (fig. 2) the movements of the same layers among the neighbouring boreholes op-8 and pz-10, then pz-1 and pb-6, pb-6 and op-4, and op-3 and ocp1 are also visible. by the analysis of the same profile the plane of marker q' is observed, which throws down gradually from north towards south from the depth of 30 m to 90 m under the sea-level. in this part of the area it is the difference of 120 m. the thickness and the composition of the deposits are changing accord­ ingly. the number of permeable (mainly sandy materials) and impermeable (mainly silty-clayey materials) lay­ ers, interbeds and lenses has increased. 3. conclusion thanks to a great number of boreholes with the geophysical measurements performed, the composition and the thickness of the quatemary sedim en ts on various parts of treated area have been determined. the zones of the increased thickness are devi ded and asymetricall y arranged in relation to the depression axis. generally geologia croatica 45 speaking, the increased thickness is nearer to the southern boundary of the depression. the zones of greater or smaller thickness exchange diagonally in the relation to the axis of the depression. on the places where the quatemary deposits are thinner, the coarse-grained clastic sediments prevail in the composition. in the thicker parts there are also fine-grained clastic sediments ranging from 3040 %, mainly in the form of lenses. the above­ mentioned suggests that, due to sinsedimentary tectonics, the sedimentation area comprised numerous local de­ pressions and rises. this paper deals with the existence of the quater­ nary tectonic activity. it appears particularly after the sedimentation of the marker horizon q', which clearly divides the complex of the middle and upper pleisto­ cene deposits from the older ones. in the area between the boundary faults, the faults of the e.n.e.w.s .w. (n.e. s.w.) system directly influence their folding and sedimentation. these circumstances are due to the regional tectonic movements, as well as to the po~tions and movement of rock masses in the nucleus of the mountains of bilogora, papuk and krndija on one side and mecsek, vi!umy and the plateau of baranja on the other side of ·the drava depression. according to grunrhal & stormeyer (1983) the direction of the regional horizontal stress in the mentioned area is approximately n.e. s.w. this speaks for the unfavourable position of the mentioned rock masses according to stress. their possible movement in space is along reverse faults which are visible in the zone of the boundary south fault of the drava valley . the movements of rock masses cause the folding of the quatemary deposits. because ofthe regional stress activity along the diagonal fault system, it is necessary to expect the movement to the left. it is visible in fig. 4, mainly in the eastern part of the area with thick or thin zones of the deposits. from the geomorphologic elements, the completeness of the route of the boundary south fault of the drava valley h_as been noticed. the crossing of the faults is possible only at našice and further to the east. another detail is emphasized, i.e. the estimated vertical movements along the following faults: the boundary south fau lt of the drava valley: 150 350 m (or 0,03 cm per year) for the period of middle -upper pleistocene and up to 90 m (o. on cm per year) only for upper pleistocene; the boundary north fault of the drava valley; possible to 150 m (0,015 cm per year); -the faults of the system e.n.e.w.s.w. (n.e. ­ s.w .), specially stretch ing by donji miholjac, beničanci, bizovac and ćepin: 100150 m (up to 0,015 cm per year). 4. references babić, ž., ćakarun, 1., sokać, a. & mraz, v. (1978): o geologiji kvartamih naslaga područja rijeke drave. geol. vjesnik, 30/1, 43-61, zagreb. prelogović & velić : correlation of quatemary sedirntmts ... boonar, a. (1990): geomorfologija baranje.znanstvena monografijaognjen prica, 1312, zagreb. galović, i. & marković, s. (1979): osnovna geološka karta sfrj l: 100 000, list virovitica, l 33-83.geol. zavod, zagreb, 1971-1975, sav. geol. zavod, beograd. galović, i. marković, s. & magdalenić, z. (1981 ): osnovna geološka karta sfrj l: l oo 000, tumač za list virovitica, l 33-83. inst. geol. istraž. zagreb, 1976, sav. geol. zavod, 1-44, beograd. grunthal, g. & stormeyer, d. (1983): stress pattern in central europe and adjacent areas. gerland beitr. geophysik, 95, 5, 443-452, leipzig. hećimović, i. (1985): osnovna geološka karta sfrj l: 100 000, list donji miholjac, l 34-73.geol. zavod, zagreb, 1981-1984, sav. geol. zavod, beograd. . hećimović, i. (1986): osnovna geološka karta sfrj 1: 100 000, tumač za list donji miholjac, l 3473.geol. zavod, zagreb, 1984, sav. geol. zavod, 1-33, beograd. · hećimović, i. & prelogović, e. (1987): tumač za list donji miholjac. geomorfološka analiza. geol. zavod, zagreb. hernitz, z. (1981): dubinski strukturno-tektonski odnosi u području istočne slavonije. disertacija. rudarsko-geološko-naftni fakultet, zagreb, (tiskano 1983, časopis nafta, 1-221, zagreb). jamičić, d. & brkić, m. (1986): osnovna geološka karta sfrj l: 100 000, list orahovica, l 33-96. geol. zavod, zagreb, 1971-1986, sav. geol. zavod, beograd. jamičić, d., brkić, m., crnko, j. & vragović, m. (1987): osnovna geološka karta sfrj 1:100 000, tumač za list orahovica, l 33-96. geol. zavod, zagreb, 1986, sav. geol. zavod, 1-72, beograd. jamičić, d. (1988): strukturni sklop slavonskih pla­ nina (sjeverni psunj, papuk, krndija). disertacija. rud.-geol.-naftni fakultet, zagreb. korolija, b. & jamičić, d. (1988): osnovna geološka karta sfrj l: 100 000, list našice, l 34-85. geol. zavod, zagreb, 1988, sav. geol. zavod, beograd. korolija, b. & jamičić, d. (1989): osnovna geološka sfrj 1:100 000, tumač za list našice, l 34-85.geol. zavod, zagreb, 1988, sav. geol. zavod, 1-40, beograd. kranjec, v., prelogović, e., hernitz, z. & blasković, i. (1971): o litofacijelnim odnosima mlađih . neogenskih i kvartarnih sedimenata u širem području bilogore. geol. vjesnik, 24, 47-55, zagreb. 159 kranjec, v. & prelogović, e. (1974): o paleogeografskim i neotektonskim odnosima u tercijaru i kvartaru na teritoriju sr hrvatske. geol. vjesnik, 27, 95-112, zagreb. magas,n. (1987): osnovnageološkakartasfrj 1:100 000, list osijek, l 34-86. geol. zavod, zagreb, 1981-1987, sav. geol. zavod, beograd. ma gas, n. (1987): osnovna geološka karta sfrj 1: 100 000, tumač za list osijek, l 34-86.geol. zavod, zagreb, 1986, sav. geol. zavod, 1-54, beograd. malez, m. (1973): kvartarne naslage šire okolice podravske slatine i orahovice u slavoniji.radovi centra za organizaciju naučnoistraž. rada u vinkovcima, jazu, 2, 5-55, zagreb. marković, s. (1986): osnovna geološka karta sfrj 1:100.000, list podravska slatina, l 33-84.geol. zavod, zagreb, 1981-1984, sav. geol. zavod, beograd. marković, s. (1986a): osnovna geološka karta sfrj l: 100 000, tumač za list podravska slatina, l 33-84. geol. zavod, zagreb, 1984, sav. geol. zavod, 141, beograd. mutić, r. (1975): sedimentološka ispitivanja nasla­ ga lesa u okolici vinkovaca, našica i valpova. geol. vjesnik, 28, 269-283, zagreb. mutić, r. (1989): korelacija kvartara istočne slavonije na osnovi podataka mineraloško-petrografskih analiza (istočna hrvatska, jugoslavija). dio i: dravska potolina. acta geologica, j u gosi. akad. znan. umjet., 19, 1-60, zagreb. pletikapić, ž., gjetvaj, i., jurković, m., uurbiha, h. & hrnčić, lj. (1964): geologija i naftoplinonosnost dravske potoline. geol. vjesnik, 17, 49-78, zagreb. prelogović, e. & cvijanović, d. (1983): prikaz neotektonske aktivnosti dijela slavonije, baranje i bačke.geol. vjesnik, 36, 241-254, zagreb. royden, l. h. & horvath, f., eds. (1988): the pannonian basin. a study in basin evolution. aapg, and hungarian g eo l. soc. memoir 45, 1-394, tulsa, budapest. sokač, a. (1976): pleistocenska fauna ostrakoda iz nekih bušotina u istočnoj slavoniji (sjeverna hrvatska).geol. vjesnik, 29, 159-172, zagreb. sokač, a., dragičević, i. & velić, j. (1982): biostratigrafske i litološke odlike neogenskih i kvartarnih sedimenata nekih bušotina okolice osijeka. geol. vjesnik, 35, 9 20, zagreb. urumović, k., hernitz, z., simon, j., & velić, j. (1976): o propusnom mediju kvartarnih te gornja i srednjopliocenskih naslaga sjeverne hrvatske.zb. radova 4. jugosl. sim p. o hidrogeol. i inž. geol., l, 395-410, skopje. . urumović, k. (1982): hidrogeološke značajke istočnog dijela dravske potoline. disertacija. rud.-geol. fak., 1-138, beograd. 160 geologia croatica 45 korelacija kvartarnih naslaga i tektonska aktivnost istočnog dijela dravske potoline e. prelogović i j. velić l. uvod u proučavanju kvartarnih naslaga panonskog bazena najčešće se pažnja obraća sastavu naslaga i to poglavito za potrebe geološkog kartiranja, hidrogeoloških, inženjersko geoloških ili klimatskih problema, te kronostratigrafskih i sedimentoloških odredbi. manje se zna o prisutnosti tektonskih pokreta, njihovim amplitudama i utjecaju u sedimentacijskim i strukturnim promjenama. o tim značajkama moglo se više doznati u razmatranom području zahvaljujući podacima bušenja, geofizičkom profiliranju i korelaciji naslaga.na raspolaganju su prvenstveno bile spoznaje polučene zadnjih desetak godina u hidrogeološkim i naftno­ geološkim istraživanjima, te geološkom kartiranju. sveobuhvatnije su kvartarne naslage podvrgnute istraživanju u okviru prikupljanja podataka za gradnju hidroelektrana na dravi. tom prilikom posebno su geološki reinterpretirani seizmički profili do dubine od 600 m i plitki geoelektrični pro fili do približno 250 m dubine. isto tako načinjena je korelacija između 45 bušotina izrađenih prigodom istraživanja ležišta nafte i podzemne vode i izdvojeni su repemi horizonti (se~ a 1). bilo je i novih geoelektričnih profila i plitkih bušotina. obavljena je determinacija jezgara iz bušotina, a u bušotinama odgovarajuća geofizička mjerenja, te paleontološke, sedimentološke i rentgenske analize. k vartarne ,naslage su, iz dosadašnjih proučavanja, selektivno dobro poznate, osobito njihov mlađi dio. osim većeg broja stručnih postoje i objavljeni radovi. sa stratigrafskog i neotektonsko strukturnog stajališta izdvajaju se najvažniji objavljeni radovi koji tretiraju facijese naslaga, paleontološke obrade uzoraka iz bušotina ili vodonosne horizonte (npr. babić et al., 1978; kranjec et al., 1971; malez, 1973; sokać, 1976; sokać et al., 1982; urumović, 1982; urumović et al., 1976). za razumijevanje odnosa kvartarnih i starijih naslaga te položaja obuhvaćenog područja u regionalnom strukturnom sklopu, pozornost se obraća relativno novijim radovima (npr. pletikapić et al., 1964; kranjec & prelogović, 1974; hernitz, 1981; prelooović & cvuanović, 1983; jamićić, 1988; royden & horvath, 1988) i tumačima osnovne geološke karte. uvažavajući literaturu i dopunjujući te podatke novima razlučeni su facijesi, ustanovljeni reperni horizonti i debljine naslaga te utjecaji tektonskih pokreta. 2. sastav, debljine i korelacija naslaga kvartarne naslage na površini dobro su proučerie i raščlanjene u osnovnoj geološkoj karti (galović & marković, 1979; galović et al., 1981; hećimović, 1985,1986; jamićić & brkić, 1986~ jamićić et al., 1987;korolua&jamićić, 1988, 1989;marković, 1986, 1986a; magaš, 1987; 1987a). iz podataka s površine kao i unutar depresije u dubini nije sigurno utvrđena granica pliocenkvartar. na obroncima krndije, papuka i bilogore izdvojeni su fluvio -jezerski šljunci, pijesci i podređeno gline u izmjeni u razdoblju pliocenkvartar. od naslaga koje se pojavljuju na površini u pleistocen su uvršteni pretežito pijesci akvatičke sredine i genetski tipovi eolskog niza, a u holocen sedirnenti fluvijalnog, eolskog, barskog i padinskog facijesa. zbog specifičnih odlika les je podrobno proučavan (npr. mutić, 1975; bognar, 1990). u zadnjih gotovo dvadesetak godina unutar kvartarnih sedimenata u dravskoj depresiji uočeno je nekoliko uvjetnih repemih horizonata. jedan od njih je q' (urumović et al., 1976) koji se relativno jasno, jednostavno i jednoznačno može odrediti na karotažnim dijagramima (slika 2). njegova je pozicija takva da dijeli kvartarne naslage na osnovi bitnih elektrofizikalnih i litoloških značajki na dva dijela. ispod q' leže donjopleistocenske, eventualno pliocenskopleistocenske taložine, a iznad srednjo­ pleistocenske, gornjopleistocenske i holocenske (urumović et al., 1976; hernitz, 1981). ove mlađe još se nazivaju i "rastresiti pokrivač". obilježava ih niski stupanj dijageneze, povećani permeabilitet i znatniji sadržaj krupnoklastičnih sedimenatašljunaka i pijesaka. stoga se na karotažnim dijagramima iskazuju s povećanim i skokovitim amplitudama. ispod uvjetnog repera q' gotovo redovito leži glinoviti sloj, a krivulje više ne pokazuju skokovite i povećane otklone. za opis naslaga iznad repera q' izabrana je kao karakteristična situacija kakva je u bušotini valpovo-l (slika 3). karotažni dijagrami iz te bušotine imaju vrlo dobru vertikalnu rezoluciju, što vjerno i vjerodostojno odražava litološki sadržaj. dakle, u krov ini re pera q' leže odozdo prem<t gore: 27,5 m debeli pjeskoviti sloj, manje više jednoličnog sastava; -prah 2,5 m debljine; -ll m debeli pijesak koji postupno prema gore sve više postaje sitnozrnast i sa sve više praha uz nešto gline; -16 m debeli sloj praha s nekoliko glinovitih proslojaka; -pijesak 36,5 m debljine s oštrom donjom granicom, dok u gornjem dijelu pokazuje postupno smanjivanje veličine zrna u nižem nivou sadrži dva prašinasta proslojka ili leće; -16,5 m debeli sitnozrnasti intervalprah i glina; jednoličan pijesak debljine 17 m; -10 m pijesak s prahom i humusom na površini. daljnje pojedinosti, pogotovo glede litološkog sastava prelogović & velić : correlation of quaternary sedirnents ... i starosti, otkrivene su pomoću dvije bušotine locirane desetak km zapadno od osijeka na desnoj obali drave koje su doprle do 100 m dubine uz kontinuirano vađenje jezgre (dz-4, dd-3a, slika 2). naslage su na terenu detaljno determinirane, a prikupljeni su i uzorci za laboratorijske analize. u bušotinama su sprovedena i geofizička mjerenja uz primjenu radioaktivnih metoda. do dubine od 100 m nalaze se u međusobnoj izmjeni pijesci, te prah i glina. pijesci prevladavaju u gornjih 50 m, a prisutne su sve frakcije prema veličini zrna, od sitnozmastih do krupnozmastih. pretežno su pepeljastosive boje uz tanje proslojke smeđastosive, žućkastosive i zelenkastosive nijanse. mjestimice je povećan sadržaj praha koji se javlja u obliku leća eme ili tamnosmeđe boje uz obilje karboniziranog biljnog trun ja. zapaženi su i krupniji paleofloristični ostaci te ugljen nisl>og stupnja karbonizacije. u nižem dijelu stupa sve je više sitnozmastih klastita -praha i gline. boje su sivozelenkaste, zelenkaste, tamnosive, tamnosmeđe ili plavkastosive. u njima se gotovo redovito javljaju konkrecije promjera od nekoliko mm do par cm, ·te fosilna fauna i flora: ostrakodi, mikromoluske, girogoniji hara i biljni plodovi. slojevi praha su laminirani, što se brzo i jednostavno uočava, jer se radi o milime~oj izmjeni bijelih i tamnosivih lamina. mineralni sastav lake i teške frakcije uzoraka pijesaka generalno je ujednačen duž cijelog 100 m-skog intervala. u sastavu lake frakcije dominantan je kvarc s udjelom od 54 76 %. slijede feldspati (1022 %) i fragmenti stijena (6 16 %), dok se ostatak do 100 % odnosi na muskovit među prozirnim, teškim mineralima prevladavaju zrnca granata dosežući od 42 do 77 %, a značajno su prisutni minerali ep ido t cois i tske skupine (8 19 %) i amfibol (823 % ). sa samo nekoliko postotaka utvrđeni su: piroksen, disten, staurolit, turmalin i apatit. ovakav sastav upućuje na stanovitu paleogeografsku rekonstrukciju (mutić, 1989.), koja u kombinaciji s rezultatima mikropaleonto­ loške obrade postaje još cjelovitija (sokač, 1976.). zaključak je da se sedimentacija odvijala u vodenim sredinama jezeru, povremeno močvari, uz prisutnost vegetacije. opravdano je ukazati i na mogućnost periodičnog presuši vanja lzvorišno područje predstavljale su metamorfne stijene. rjeđe stariji klastiti, a vrlo rijetko magmatiti. iz strukturnog stajališta posebno je bilo važno utvrditi debljine naslaga iznad repemog horizonta q'. to se rela­ tivno detaljno učinilo zahvaljujući mreži seizmičkih i geoelektričnih profila i dosta povoljnom rasporedu bušotina. ako se promatra-cjelovito, dravska depresija je generalnog pravca pružanja sz-ji (zsz-iji). neogenske naslage pokazuju asimetričnost depresije. glavna os proteže se bliže krndiji i bilogori, a od podravske slatine prema zapadu čak neposredno uz zonu južnog rubnog rasjeda dravske depresije. k vartame naslage samo d jelo mice prate trend uočen za neogenske taložine. iznenađuju dvije činjenice. prvo, u većem dijelu depresije naslage su deblje od 200 m, mjestimice iznad 300 m, a između kapelne i mikleuša čak iznad 400 m (slika 4). drugo, naslage su borane i rasjednute dijagonalno na pružanje depresije (slika 4 i 5). ističu se zone zadebljanja naslaga: južno od bizovca, 161 istočno od valpova, jugozapadno od kapelne i osobito d. miholjca, te paralelno bilogori od mikleuša prema zapadu. također i zone zatan jenja naslaga: oko beničanaca, bizovca, valpova, čepina, osijeka i istočno od našica. nagla zadebljanja naslaga ukazuju na aktivne rasjede. što se rasjeda tiče naglašavaju se slijedeće činjenice: naslage su zadebljane ili skokovito pomaknute duž rubnih ras jeda depresije, ali i duž sustava rasjeda isi-zjz (si-jz); dijagonalni sustav predstavljaju strmo nagnuti ras jedi duž kojih su, osim vertikalnih, zamijećeni i horizontalni pomaci; ti rasjedi su sinsedimentacijski, pa izravno utječu na promjene sastava i debljine naslaga; -taj utjecaj naročito je vidi j iv između ras jeda koji dotiču d. miholjac i čepin; -ras jedi prikazani na slici 5 sijeku kvartarne naslage: prema geomorfološkim odlikama reljefa (hećimović & prelogović, 1987) i na satelitskim snimcima osobito se na površini ističu trase južnog rubnog ras jeda dravske potoline, djelomice sjevernog rubnog rasjeda dravske poto line, te dijagonalnih ras jeda koji dotiču d. miholjac, kapelnu, beničance, bizovac i čepin (zapravo dionice naglih promjena debljina vidljivih na slici 4). za ilustraciju postojanja sustava ras jeda isi-zjz (si­ jz) na slici 6 prikazuje se dio seizmičkog profila snimljenog 1958. godine okolice kapelne. u istom smislu na korelacijskom profilu (slika 2) razabiru se pomaci istih slojeva između bliskih bušotina op-8 i pz-10, zatim pz1 i pb-6, pb-6 i op-4, te op-3 i očp-1. promatranjem istog profila prati se ploha repera q' koja postupno tone od sjevera prema jugu, od dubine 30 m na -90 m. u ovom dijelu terena to je razlika od 120m. sukladno s tim mijenjaju se debljine i sastav naslaga. povećava se broj slojeva, proslojaka i leća propusnih (pretežno pjeskovitih) i nepropusnih (pretežno glinovito siltnih) taložina. 3. zaključak zahvaljujući velikom broju bušotina u kojima je obavljeno geofizičko mjerenje, ustanovljen je sastav i debljina kvartarnih ·taložina u različitim dijelovima obrađivanoga terena. zone povećanih debljina međusobno su razmaknute i u odnosu na geografsku os depresije nesimetrično raspoređene. općenito, povećane debljine bliže su južnom dijelu potoline. također zone većih ili manjih debljina izmjenjuju se dijagonalno. nadalje, tamo gdje su kvartarne naslage tanje, u sastavu prevladavaju krupnozmasti klastiti. u njihovom debljem slijedu javljaju se i sitnozmasti klastiti s udjelom od 30 do 40 %, pretežito u obliku leća. to znači da je sedimentacijski prostor bio razveden na brojne lokalne uleknine ili izdignuća, ovisno o utjecaju sinsedimentacijskih tektonskih pokreta. iz navedenog proizlazi postojanje kvartarne tektonske aktivnosti. osobito je ona naglašena nakon taloženja repernog horizonta q' koji jasno odjeljuje kompleks srednjo i gornjopleistocenskih naslaga od starijih. u prostoru između rubnih ras jeda na boran je i sedimentaciju ovih naslaga izravno utječu rasjedi sustava isi-zjz (si162 jz). te okolnosti posljedica su regionalnih tektonskih pokreta, te položaja i pomaka masa s ti jena u dubini bilogore, papuka i krndije s jedne i mecseka, villanya i baranje s druge strane dravske depresije. prema grunthalu & stormeyeru (1983.) pravac djelovanja regionalnog horizontalnog stresa u obuhvaćenom području je približno si-jz. to ukazuje na nepovoljni položaj spomenutih masa stijena spram stresa. mogući njihov pomak u prostoru je po reversnim rasjedima vidljivima u zoni južnog rubnog ras jeda dravske depresije. pomaci masa stijena uzrokuju boran je kvartarnih naslaga. zbog djelovanja regionalnog stresa duž dijagonalnog sustava rasjeda mora doći i do lijevog pomaka krila. to je vidljivo na slici 4 pretežito u istočnom dijelu područja uz nizanje zona zadebljanja ili zatanjenja naslaga. iz geomorfoloških podataka je još zapažena cjelovitost trase južnog rubnog ras jeda dravske geologia croatica 45 depresije. presijecanje je moguće prisutno jedino kod našica ili dalje istočno. ističe se još jedan detalj i to utvrđeni vertikalni pomaci duž slijedećih rasjeda: -južni rubni rasjed dravske depresije: 150350 m (ili 0,03 cm/god), za razdoblje srednji -gornji pleistocen i do 90 m (o.du cm/god) samo za gornji pleistocen. -sjeverni rubni rasjed dravske depresije: moguće do 150 m (0,015 cm/god); -ras jedi sustava isi-zjz (si-jz), osobito koji dotiču d. miholjac, beničance, bizovac i čepin: 100150 m (do 0,015 cm/god). manuscript recived march, 31.1992. revised manuscript accepted july, 31.1992. geol. croat. 51/2 zagreb 1998 in memoriam mr sc. leon nikler (1932 1997) leon nikle r. retired geologist and former director of the institute of geology zagreb died on september 7, 1997 aged 64, in zagreb. he was born in maribor (slo~ venia) on september 12, 1932. nikler studied geology at the faculty o r natural sciences, univers it y of zag­ reb, where he g raduated in 1957 and earned hi s m.sc. degree in 1964. from 1966 to 1975 he was the director of the institute of geo logy, zagreb, and retired in 1994 because of health problems. after his graduation, leon niklcr was appointed to the inst itute of geology in 1958, where he stayed until the end of his career. initially. he was most ly involved wi th the geological mapping of easte rn and central cro­ atia (s iavonija, kordun), and from 1961 in the dinaride karst, velika kape la, velebit and lika. he was one of the founders and leaders of the importanl geo logical project· the basic geological map, sca le i: 100.000 during the 1960 's and 70's. in his sc ientific work he made a very considerable contribution to the stratigra­ phy of the mesozoic shallow-wate r carbonates of the adriatic carbonate platform , cspecially the biostratig­ raphy and palaeontology of jurassic depos its. among many papers those concern ing the jurass ic and lower cretaceous calcareous algae (together with b. sokac) are the most important. he is also the author of numer­ ous studies and reports deposited in the archive of the institute of geology zagreb. u occkivanju da sc nakon bolesti oporavi iznenad ila nas je luzna vijest da je nas kolega mr sc. leon nikler, bivsi dircktor instituta za geoloska istrazi vanja i dllgo­ godisnji direktor zavoda za mineralogiju , petrogra fiju i mincralne sirovine, nakon duze boicsti premintlo 7. ruj ­ na 1997. ovimc j e iz nase srcd ine i hrvatske geologijc nepovratno olisao kolcga, suradnik, istrazivac i rav­ na tc lj koji j e svojim llkupnim aktivnostima ostavio vidljivo svjcdocanstvo svog zivota i rada, poglavito u svojoj radnoj sredini instilutu za geoloska istrazivanja u zagrebu. pokojni mr sc. leon nikle r, dipl.ing.geol. , rodcn je 12.09. 1932. u mariboru. osnov nu skolu zapoceo j e pohadati 1i celjll iz kojega jc 1i vihorll ii. svjetskog rata s cije lom obilelji deportiran , pa skoiovanje nastav lj a 1i zagrebu gdje i matllriral951. iste god ine up isao jc stlldij geo log ijc na geol oskom odjelll prirodos lovno­ matemalickog fakuhcta svclicili sta u zagrebu gdjc je i diplomirao 22.04.1957. iz slfukc geologija i paleonto ­ logija. postdiplomski studij zavrsio je 1964. na prirodo­ slovno-matematickom fakult etu obranom magislarskog rada " razvoj jure ii sjcverozapadnom dije lu vel ike kape le". vee tijckom stuclija naglaseno je iskazivao in tc rcs za geologiju i tercnski rad, pa je sudjelovao na geoloskom kartiranju dijela ravnih kotara , priprcmnim radovima kasnijih naftno-gcoloskih istrazivanja. l zraziti smisao za uocavanje i interprctacijll geoloskih odnosa prilikom gcoloskog kartiranja, al i i s osjeeaj za ckipni rad i f ivot u terensk im uvje tima odredili su nj egovo zaposljavanje u institutu za geoloska islrazivanja u zag­ rebu 1958. ad prvih dana usmjeren je na izradu geolo­ skih kamta, pa kao pripravnik sucljejuj e u kartiranju petrove gore, kmdije i papuka ie dijeja banov ine da bi 210 vee 1961. preuzeo ckipu i odgovornosl izrade osnovne geoloske karte l : i 00.000 (ogk) dijcla li sta crikvenica u podrucju mrkoplj a, mal ic poijane, bij e lih i samar­ skih stijena u vclikoj kapcli. u lom podrucju cc susrct s (zv. "lemeskim naslagama" i njihovom amonilnom fau nom, ie fos il ifernim prigrebenskim razvojcm tilona, bi li presudan za njcgov kasnij i rad i in tcrcs kojcl11 cc se pok. kolega nikler jos dugo vracali. taj prvi znanstvcni intercs rcali zira se u dva vrijedna rada: " razvoj jure u sjeverozapadnolll di jcl u vel ike kapcjc" i " ncrineje lilona velike kapcjc". o bdoa titonska faun a prikupljc­ na na lokalitelim a dinare, sv ilaj e i korduna ostati cc nazalos t neob radcn3 i sarno zclja pot isnu ta dncvnim obvezama uprav ljanja i izgradnje inst itut a. ova prcki­ nu ta ist razivanj a biti cc kasnije ba rcm dijc lom obu h­ vacena radom "stratigrafsk i polozaj grebcnskog facije­ sa malma u sjevcrozapadnim dijelovima dinarida". lzrada ogk koja sc realizira u koautorslvu l. n iklcra i suradnika grafi ckom i teks tualnom intcrpretae ijom li s­ lova: obrovae, udbina, gospic, zadar, otoeae i crikvc­ niea omoguci la je prikupljanjc obilja ros ilnog matc ri­ ja la i tcrcnsku analizu facijcsa mezozoika spomenutih podrucja s lezistc l11 niklerovih istrazivanja poglavito jurskih naslaga. goiovo da jc to u nas bio pocetak sus­ tavnog islraz ivanja m ikrofosilnih zajednica mezozoika. iz tog perioda vrijeclno jc spomcnuti radove: "fos iinc dasyeladaecac gornjc j ure velcbita i sj cvc rozapadnc vclikc kapc lc" i "biostratigrafijajurc vclcbita", dok se v ise radova odnosi na kriti cku anali zu taksonomskc klasifikac ije i opisa novi h taksona vapncnacki h alga iz jursk ih i krednih naslaga s irom dinarida. rad na gco­ loskim kartama ogieda se nc samo u aulorstvu spo­ mcnuti h li stova, vcc predstavlja lelllclj dalj nje razrade i objavljivanja c janaka s pri kazom regional nih znacajka, tektonskih odlika dije lova tcrena iii strati grarskc pri­ padnosli pojedinih nivoa iii lokaliteta kao sio sli prim­ jerice "gcologija podrucja zapadno od krbavskog po­ ija", " slrukturna grada jugois locnog vclcbita" iii "starost klilllenla vapnenaca" i df. kao vrsnom tere n­ skom istrazivac u nijc illu promakla morfoloska 050bitos! pianin skc zaravni u prcdjelu vclikog i malog rujna, oglavinovca i javornika u velebitu, gdje j e utvrdcn morensk i malc rijal i g lacioiluvijativ ni nanos, sio jc niklcr inlerprelirao kao siguran dokaz osporavanc oleclbe ve lebita za koju kazc da joj tragove trcba traz iti l1a sjevernilll pad inama. vrijcdan jc i koautorski rad 0 na lazu s taklastog lufa u " lemcskim"-gornjojurskim nasiagama vclike kapclc koji jc barell1 dije lom ponu­ dio odgovor na pilanje 0 podrijcll u sili cija (roznjaka) u ovim naslagama. l zrazeni sm isao za poslovnost i orgallizacij ske spo­ sobnosti ubrzo ga ( 1964) dovode na mjesto scra odjcla za geojogiju i pajcontologiju na kojcm, uz punu angazi ­ ranosl na slrucnom radu uspjcsno djclujc do 1966. kada jc izabran za dircklora institula. bilo jc 10 vrijeme prigeologia croatic3 51!2 vred nih reformi koje su zahljcva le n iz novih o blika organi ziranja i novog naci na poslovanja instituta, pa cc njegova, premda jos uvij ck vid na, slrucna aktivn ost postupno jenjavatl u upravljanju institutom intuitivllo je pronaiazio najpovoljnija rjesenja i poslovnc poteze, vodeci pri odlucivanju brigu 0 polozaju i ulozi instituta i geologijc u hrvatskoj . narocitu paznj u i energiju usm­ jcravao jc osiguravanju povoljn ih uvjcta i m aterijalne osnove za kontinuirani rad na tada kapitalnom projektu izrade osnovne geoloske ka rtc sfrj 1:100.000 u hrva­ tskoj. u obavljanju svojih duznosli i ispunjavallju obvc­ za uvijck je vodio bri gu 0 suradnic ima i kolegama na pos lu, uvjeti ma njihovog racla i osobnim pot rcbama. o tudenjem zgrade i g ub il kom radnog p rostora pocetkom 70-tih godina il1s titut se d islocira na nckoliko mjcsta, pa je namclnul.a poi reba izgradnjc nove zgrade sa suvremcnim kabinclima, knjiznicom i laboralorijem slo l nikler zajeclno sa 5uradnic ima i ostvarujc, pa jl1u i u tom pogled u dug uj cmo posebnu zahvaln ost. kao direklor bio jc clan pojedinih znanstvcn ih tije la u repu­ blici, akt ivan je slidionik j orga ni za tor kongrcsa, s im ­ poz ij a , savjctovanja , c lan j e raz licit ih udrll zenja 1i zell1 lji i inozcmslvu. u svoil1 radu posvccivao jc paznju mcd unaroclnoj suradnji te jc promicao medll sobne zllanslvene i strucne konlakle s pojcdineima i instituc i­ jama iz polj ske, madarskc, njcmacke, siovackc, ccskc, francuskc, ila1ijc i df. oclrzavao je i njegovao s ta lnc kontakt e s fakul letima, akadcmijinim savjc tima i part­ ncrskim firmama: naftapl inom, geofizikom , gcoteh­ nikolll , ig h i drugi m broj nim organizacijama, naslojeci da njcgova mat icna kuca uvijek budc u fifi drustveno­ gospodarskih i strucno-zllanstvcni h zbivanja i polrcba ii rcpubl ici. od 1966. do 1975. bio.ie odgovorni li rcdnik casopisa "geoloski vjcsnik", elllgogod isnji jc clan i-1 rva­ tskog gcoloskog druslva, a ii elva navrata bio jc prcd­ sjcdn ik drustva inzenjcra i tchnicara hrvatskc. god inc 1975. ponovno sc llk ljuc ujc u s lrucno­ znanstvcne pos love u zavod u za mine ralog iju , pclro­ grafiju i mineralne sirovi nc gdje se angazira na pro­ gramiranju i ist razivanju ugjjcnih iczisla u raz lic ilim poelrucj ima hrvalske ie istraz ivanja ncmclal a poglavito boks it a. iz log perioda mnogo vr ijcdnih z llanslvcni h rczu itala i zapaz.anja, zbog lajnosli poela taka, oslajc nc­ objav ljcno i prikrivcno ii broj nim c laboratima , izvje­ staj ima iii same nj ihovim sazclcima, pa je tim znacajni­ je spomenllti rad: "znacaj i karaktcrisl ike smcdih llg jjc­ na da lmacije". godinc 1977. izabran jc za dircklo ra spomcnu(og zavoda, pa lu duzilosl obavlj a svc do um i­ roy l.i cnja 1994. smrctl mr sc. lcona niklcra hrvats ka gco logija jc izgubila uzornog strucnjaka i znanslvenika, a n~sa rad­ na sred ina kolegu j prijat c jja , cijenjenog ravna lc lja pr imjc rnih moral nih osobi na, kojcga cemo zad rza ti 1i traj noj li spomeni. dcan boskov1 c branko sokac in mclllori;l1n: mr sc . leon nrkler 211 popis obja vljenih radova bibliography 1. iy anoyic, a., sokac, b. & nikler, l. (1962): dber das alter der kalkbroksien des sud­ ostlichen teiles des yelebit." bull. sci. cons. acad. yougosl., 7/6, 160, zagreb. 2. nikler, l. , sokac, b. & iy anoyic, a. (1964): die gasellschartcn del' mikrofossilicn del' jura lind kreide des sudbst li chcn vclebit.bull. sci. cons. acad. yougosl.,9/3, 67-68, zagreb. 3. sokac, b., nikler, l. & iy anoyic, a. (1964): fund von obertriadischen dasycladaceen im gebiet des yelebit.bull. sci. cons. acad. you­ gosl. , (a), 9/6,156-157, zagreb. 4. sokac, b., nikler, l., swsnjara, a. & tv a­ noyic, a. (1964): die stratigraphische lage dcs "kl inentalkalkes". bull. sci. cons. acad. you­ gosl., 9/1-2, 8, zagreb. 5. nikler, l. , (1965): entwicklung del' jura in dcm nordwcstlichcn tcile der velika kapeia.bull. sc i. cons. acad. yougosl., (a), 10/1 ,3-4, zagreb. 6. nikler, l., iyanoyic, a., sokac, b. & ye­ llc, i. (1965): die geologie dcs gcbictcs wcsllich von krbavsko polje.bull. sci. cons. acad. you­ gosl., (a), 10/7-8,2 13-2 15, zagreb. 7. ntk ler, l. & sokac, b. (1965): die notwcn­ digkcit der einftihrung von zwei subgenuse bei der gattung macroporella.bull. sci. cons. acad. you­ gosl., (a), 10/4, 105, zagreb. 8. nikler, l. & sokac, b. (i965): cylindroporc­ lia anici n.sp. new dasycladaceae from the maim of yelebit.bull. sci. cons. acad. yougosl., (17), 10/4, 106-107, zagreb. 9. nikler, l., sokac, b. & ty anoyic, a. (1965): strukturna grada jugoistocnog yelebita. ­ acta geol., 5 (pri!". ist!". jugosl. akad. znan. um.iel. , 35),389-395, zagreb. 10. sokac, b. & nikler, l. (1966): two new spe­ cies of the genus pelrascuia from the lower lias of the velebit mountain.bull. sci. cons. acad., you­ gosl. , (a), 11/1-2,7-8, zagreb. ii. iy anoyic, a., yellc, i., sokac, b. & nik­ ler, l. (1967): geologija podrucja zapadno od krbavskog polja.krs jugoslavije, 5, 13-26, za­ greb. 12. nikler, l. & sokac, b. (1967): fossil dasycla­ daceae from upper jurassic of the mount velcbit and the nw part of the mount velika kapela.rad jugosl. akad . znan . umjet., 345, 10 1-134, zagreb. 13. sokac, b. & nikler, l. (1967): tculloporclia clongatula (praturlon, 1966), sakai: & nik ler, cal­ careous alga from lhe middle liassic of yelebit.­ gcol. vjcsnik, 20, 111 116, zagreb. 14. nikler, l. & sokac, b. (1968): biostratigraphy of the jurassic of velebit (croatia).geol. vjcsnik, 2 1, 161 -176. 15. nikler, l. (1969): nerineje tilona yclikc kapele (die nerineen des tithons von velika kapela).­ geol. vjesnik, 22 ( 1968), 219-227. 16. sokac, b. & nikler, l. (1969): dinarella kochi n.gen ., n.sp. (dasycladaceae) from the lias of the yelebit mountain.geol. vjcsnik, 22, 303-308. 17. sokac, b. & nikler, l. (1969): 0 vrstama roda petrascula iz donjeg lijasa yelebita.acta geol., 6 (prir. istr., jugosl. akad. zoan. umjet., 36), 103-112, zagreb. 18. gusic, i. , nikler , l. & sokac, b. (1970): the jurassic in the dinaric mountains of croatia and the problems of its subdivisions.ann. inst. gcol. pubj. i-tung. (coli. jurassique meditcrr., budapest, 1969), 54/2,165-183, budapest. 19. majcen, z., koroltja, b., sokac, b. & nikler, l. (1970): osnovna geoloska km1a sfrj i: 100.000. lisl zadar, l33-129, inst. geol. islr., zagreb. ( 1936-1969), savezni geol. zavod, beo­ grad. 20. nikler, l. & sokac, b. (1970): clypeina ealei­ formis il. sp., a new calcareous alga (dasyc iada­ ccac) from the upper jurassic of lastovo island.­ gcol. vjesnik, 23,139-144. 21. susnjar, m., bukoyac, j., ntkler, l., crnolatac, i., milan, a., stkic, d., gri­ mant, i., vultc, z. & blaskoyic, i. (1970): osnovna geoloska karta sfrj i: 100.000. list crikvenica 1.33-102.inst. geol. istr. zagreb (19611969), say. geol. zavod, beograd. 22. sokac, b. & nikler, l. (197 j): cymopol ia longistila n.sp. a new calcareous alga (dasyclada­ ceae) from the lower cretaceous of thc dinaric mountains.geoj. vjesnik, 24, 77-84. 23. grimani, i., susnjar, m., bukov ac, j., mt­ lan, a., nikler, l., crnolatac, i. , sikic, d. & blaskoyic, i. (1973): osnovna geoloska karta sfrj i: j 00.000. tumac za list crikveni ea l33-102.inst. geol. islrai. zagreb (1963), savezni geol. zavod, beograd, 47 p. 212 24. iv anovic, a. , sakac, k., markovic, s., sokac, b., susnjar, m., nikler, l. & sus­ njara, a. (1973): osnovna geoloska karta sfrj i: 100.000. list obrovac l33-140.ins!. geol. istr., zagreb (1962-1967), savezni geol. zavod, beograd. 25. nikler, l. (1973): nov i prilog poznavanju olect­ be velebita (ein neuer beitrag zur kenntnis cler vereisung im velebit gebirge).geol. vjesnik, 25 (1971),109112. 26. sokac, b. & nikler, l. (1973): calcareous alga from the lower cretaceous of the environs of niksic, crna gora (montcncgro).palcont. lugos!., 13, 1-57, zagreb. 27. sokac, b. & n1kler, l. (1973): linoporeila kapcl cnsis n.sp. (dasycladaccac) from the titho­ nian of m!. velika kapela.geol. vjesnik, 25, 65 71, zagreb. 28 . susnjar, m. , sokac, b., bah un, s., buko­ vac , j. , nikler, l. & iv anovic, a. (1973): osnovna geo loska karta sfrj ll00.000. list udbina l33-128 .in s!. geol. istr. zagreb (1963 1965), savezni geol. zavod, beograd. 29. sokac, b., nikler, l., velic, i. & mamu­ zic , p. (1974): osoovna geoloska karta sfrj 1: 100.000. li st gospic l33-127.ins!. geol. istr. zagreb (1963-1967), savezni geol. zavoct, beograd. geologia croatica 51/2 30. sokac, b. & nikler, l. (1975): two varieties of triploporella marsicalla pratudol1 and triplo­ parella issaoensis n.sp. (calcareous algae, dasy­ cladaccac) from the lower cretaceous of the island of vis (dalmatia, southern croatia).geol. vjcsnik, 28,119-131, zagreb. 31. scavnicar, b. & nikler, l. (1976): staklasti tuf u lemeskim naslagama velikc kapele (v itric turr in upper jurassic lcmcs-deposils of mc veli­ ka kapela (croatia».geol. vjcsnik, 29, 269-275. 32. nikler, l. (1978): stratigrafski poloiaj grebcn­ skog facijesa malma u sjeverozapadnim dijeiovima dinarida (stratigraphic position of the malmian reef facies in northwestern dinarids).geol. vjes­ nik, 30/1,137-150. 33. nikler, l. ( 1982): znacaj i kanl~tcristikc smcctih ugljcna dalmacije (importance and characteristics or the lignites of dalmatia).geol. vjesoik, 35, 181 -194. 34. susnjara, a., krkalo, e., braun, k. & nikler, l. (1982): istrazivanjc mineralnih siro­ vina u sr i-irvatskoj oct 1976. do 1981.geol. vjcs­ nik, 35, 244-247. juhasz et al.indd alluvial architecture and fluvial cycles in quaternary deposits in a continental interior basin, e hungary györgyi juhász, pál müller and ágnes tóth-makk 1. introduction in the investigations of quaternary systems, terrestrial deposits generally represent only a selected set of climatic events and are discontinuous in time and space. correlation of the different non-marine to the quasicontinuous deep-marine sequences and ice-cores, which provide superb tools for the global analysis of pleistocene climatic events and cycles, is rather ambiguous. a prerequisite to examine a continuous terrestrial sedimentary succession is to find a continuously subsiding basin where there is high potential for the deposition and preservation of a quaternary sequence of considerable thickness. a promising site for this is the pannonian basin system having several sub-basins which fulfil this criterion. the potential role of the deepest sub-basins of the pannonian basin as key sites for continuous quaternary terrestrial sequences was already recognized in the 1970’s and an extended investigation was initiated including drillings with full core recovery and subsequent palaeomagnetic measurement (cooke et al., 1979; rónai, 1985). the körös basin can be recorded as a reference area having a continental quaternary sedimentary succession averaging 400–500 m thick, comprising three wells with continuous cores and numerous lab tests. several studies were undertaken here and cycles of different scales (called half-cycles) were recognized in various numbers (molnár, 1973; miháltz-faragó, 1982; rónai, 1985). two of the cored wells with palaeomagnetic data were recently investigated and prove that sedimentation was continuous in the basin at least on the scale of 5th-order (40 ka as well as 100 ka) milankovitch cycles (nádor et al., 2000). moreover, there are hundreds of wells in the area drilled for water prospecting and hydrocarbon exploration. analysis of the well log response opened new possibilities for further progress and most of the sedimentological work for this study was therefore based on well-logs, but also utilised data of the cored wells. after the concept of sequence stratigraphy was introduced for fluvial basins, most of the work was done on large coastal plains but increasingly an approach and synthesis was published for continental interior basins (posamentier & allen, 1991; shanley & mccabe, 1994, 1998; legarreta & uliana, geologia croatica 57/2 171–190 13 figs. zagreb 2004 key words: fluvial sedimentology, depositional cycles, sequence stratigraphy, quaternary, körös basin, pannonian basin system, hungary. department of basin analysis, geological institute of hungary, stefánia st. 14, h-1143 budapest, hungary; e-mail: juhasz@mafi.hu abstract the thickness of the studied quaternary alluvial complex, located in the eastern part of the pannonian basin system, can exceed 500 m. based on subsurface facies analysis the following large-scale depositional elements were identified: channel-fill deposits, point bar deposits, alluvial fan (sandy sheet-flood) deposits, floodplain and floodbasin deposits, and thinner sandy–silty beds. they are classified into four types of facies associations, showing a characteristic stacking pattern on the logs. facies zonation and basin-scale facies mapping of the overall quaternary sedimentary succession shows that in several areas dominated by stacked, multistorey sandy channel fill sediments, pre-existing superimposed channel belts can be presumed. in the central and deepest part of the basin muddy floodbasin (distal floodplain and wetland) sediments dominate. between these the largest area represents the floodplain where single channel fill sands are interbedded in the alluvial plain muds. in the eastern part of the basin the well-logs highlight the distal part of an alluvial fan where sandy sheet-flood deposits alternate with floodplain sediments. the recognized facies associations show a vertical pattern, i.e. they form a 40–100 m thick fining-upward fluvial cycle. the most characteristic and even ideal cycle can be observed in the channel belts and in the proximal floodplain zone. here the basal member of the cycle is made up of multistorey channel fill beds cut into the underlying floodplain deposits. this is overlain by an alternating sandy–muddy succession of channel fill and floodplain deposits forming the intermediate member. the upper member is composed of silty–clayey floodplain deposits with occasional very thin, discrete silty–sandy bodies. these three members form a fining upward sedimentary cycle interpreted as representing low-, increasingand high-accumulation space deposits, respectively. as the basal multistorey channel fill sandstone facies association generally proved to lie above an extensive erosional surface which can be correlated regionally in the basin, allocyclic controls can be assumed. in some parts of the basin the cycle is not complete as the incised channels can be single, so the low-accumulation space deposits can be missing and the high accumulation space deposits, i.e. the aggrading floodplain sediments, can be truncated. on a regional scale, six regionally extensive cycles were differentiated above each other. although these cycles were allocyclic the question of whether they were tectonically or climatically driven remains open. however, the fact that six of them have been identified, suggests that they represent the large-scale 400 ka milankovitch cycles during the quaternary. the tectonic overprint is apparent in the thickness and internal architecture of the individual cycles. 172 geologia croatica 57/2 173juhász, müller & tóth-makk: alluvial architecture and fluvial cycles in quaternary deposits... 1998; schumm, 1993; ethridge et al., 1998; quirk, 1996; blum & törnqvist, 2000; miall, 2002). terminology, however, has been rather diverse as the sequence stratigraphic terms were worked out for coastal and nearshore settings and these do not really fit into an alluvial complex. as our time range during the quaternary refers to the milankovitch frequency band deciding whether to speak in terms of cycles or sequences is also a problem (vail et al., 1991). finally, cycles rather than sequences were chosen as sequences are better used for 3rd order cycles. the aim of this study was to reveal the alluvial and stratigraphic architecture of the quaternary sediments (sensu miall, 1996) based on the sedimentological and sequence stratigraphic interpretation of some 60 well-logs. the fluvial systems were reconstructed on a basin scale, as well as the areal distribution of the facies and facies associations. the whole succession was subdivided and correlated on the basis of stacking of the large-scale alluvial elements of the fluvial succession, using subsurface methods, wells, cores and wireline logs, due to the lack of any outcrops. this study is the first assessment of ongoing work. 2. geological setting the körös basin is a quaternary continental interior basin lying in the eastern part of hungary (figs. 1 and 2). it is one of the sub-basins of the pannonian basin with high subsidence rates, both preceding and during the quaternary. it comprises the present-day floodplain of the river körös and its tributaries; the sebes–körös, fehér–körös, fekete–körös and the berettyó. these four small rivers drain the apuseni mountains in romania, not far from the study area. the confluence of these transverse rivers clearly pinpoints the present-day depocentre. the körös river joins the tisza, an axial river flowing to the south in the central part of the pannonian basin. the basin surface is remarkably flat and all geomorphological observations substantiate active subsidence of the basin (cooke et al., 1979; rónai, 1985). in spite of the fact that it is connected to the sea by axial rivers, there are several barriers on its way (e.g. in the western part of the körös basin, see fig. 2), therefore it can be considered as a continental interior basin. the river tisza serves as a local base level and its changes or avulsions can modify the whole fluvial system of the basin. the formation of the pannonian basin system began during the middle miocene as a back-arc extensional basin connected to the uplift of the carpathians, and the subsidence of the basin has been more or less continuous, interrupted by inversion several times (royden & horváth, 1988; horváth & cloetingh, 1996). due to its complicated tectonic history, subsidence was differential in space and time, thus a series of sub-basins were formed. the huge lake pannon occupied the basin and was infilled by an enormous amount of terrigenous clastic sediments transported to fig. 1 location of the study area. 172 geologia croatica 57/2 173juhász, müller & tóth-makk: alluvial architecture and fluvial cycles in quaternary deposits... the basin by large rivers draining the emerging marginal mountains. by pliocene times the lake was filled with an extremely thick lacustrine sedimentary sequence and fluvial sedimentation occurred (bérczi & phillips, 1985; juhász, 1991, 1994). basin inversion during the quaternary resulted in significant uplift of the marginal areas and local subsidence of the basin centre (royden & horváth, 1988; nagymarosy & müller, 1988; horváth & cloetingh, 1996). the deepest parts of the basin, however, are still subsiding, although the depocentres migrated slightly after the compressional phase. the studied körös basin is one of these continuously subsiding areas where fluvial sedimentation occurred in an interior basin distant from the sea, and sediment thickness reached 400–500 m in the study area (fig. 2). 3. methodology and datasets the work has been carried out by subsurface facies analysis, correlating large-scale architectural components (sensu miall, 1996) and tracing unconformity bounded stratigraphic units on a basinal scale, using mostly wireline-log datasets. the terminology of the paper from a sedimentological and stratigraphical viewpoint refers to miall (1996). the sequence stratigraphic terminology is discussed in detail in section 6. hundreds of wells have been drilled in the area, and the best available lithological data and logs were provided by the water prospecting wells. these wells do not have cores but they have fairly good quality well-logs, generally sp, resistivity and in some cases gamma ray. for this reason most of the sedimentological interpretation was based on the analysis of the well-log response. on seismic sections unfortunately only the lower boundary of the quaternary succession was visible. some 65 water-prospecting wells along geological profiles were chosen for analysis and interpretation. the distance between the wells was generally 5 to 15 km. the results of the fully cored wells were also taken into consideration. on the basis of the well-log shapes and stacking of vertical profiles not only can lithological interpretation be made, but also subsurface facies analysis (“electrofacies”) as well as environmental and stratigraphic interpretation (pirson, 1970; serra, 1985). log interpretation may provide larger scale (lithoand sequence-) stratigraphic and sedimentological interpretation than that of the fully cored boreholes. the overall tendencies and larger bedforms of a thick sedimentary succession (i.e. fining-upward cycles) can be identified more easily, therefore it is suitable for large-scale architectural and stratigraphic reconstruction. however, sedimentary structures and other important details remain hidden in this kind of interpretation. the main problems with vertical profile interpretation are that (1) in some cases allogenic and authogenic processes can lead to the same vertical succession, and (2) similar vertical profiles can be generated in rivers by different autogenic processes (miall, 1996). fig. 2 isopach map of the quaternary complex in the hungarian plain indicating the study area, the körös basin (modified after isopach map of the quaternary sediments by rónai & franyó in borsy, 1992). 174 geologia croatica 57/2 175juhász, müller & tóth-makk: alluvial architecture and fluvial cycles in quaternary deposits... as the distance between the individual wells were several (5–15) kilometres, correlation and interpretation could be carried out on a basin scale, and we interpreted thicker packages, or large-scale depositional units. 4. alluvial architecture the lithostratigraphy and architecture of the studied quaternary succession of the körös basin is rather complex. variations both in space and time, i.e. horizontal and vertical tendencies can be observed in the alluvial architecture of the basin. the smallest recognizable units on the studied well-logs were the “electrofacies” (e.g. sand bodies with characteristic log shapes), characterized in the previous section. the thickness of the identified facies units is between 3 and 30 m in the wells. the identified facies are stacked into a vertical pattern forming characteristic facies associations or facies assemblages in many of the wells. 4.1. depositional facies on the basis of the well-logs, these facies units were interpreted as the large-scale depositional elements sensu miall (1996). logs obviously do not show the internal architecture of the individual channel fill deposits, hierarchy of bounding surfaces, internal and external geometry, etc. nevertheless, the main depositional elements identified through log-shape characteristics, and their stacking pattern, provide a view on the overall architectural build-up. all the elements which were interpreted were on a scale of several tens of metres, with obvious trends. little interpretation was possible on the thinner (1–2 m) sands and silts. the main depositional elements distinguished on the basis of well-logs were channel, floodplain, and point bar deposits. the thinner sandy–silty beds comprise natural levee, crevasse splay and aeolian deposits in the thick quaternary fluvial succession of the körös basin, as well as alluvial fan deposits in the e part of the basin (fig. 3). the floodplains of several rivers merge here even today forming a wide area comprising the whole körös basin. earlier, before regulation of the rivers it was a wetland, or small lakes could be found depending on the pre-existing groundwater-level. this is why the term flood-basin would be a better fit for this environment. aeolian sediments could not be differentiated on the basis of well-logs but the proportion of loess is probably either negligible in the thick fluvial sequence or occurs in the form of reworked loess on the basis of fully-cored wells. they can be incorporated into the thinner sandy–silty facies or the flood-basin sediments. channel-fill deposits the sandy channel-fill deposits have a very characteristic appearance on well logs. their sharp bases indicate down-cutting into clayey or silty floodplain sediments and the log motif can be either a cylinder or bell shaped, and smooth or slightly serrated. therefore they show great variability in terms of thickness, stacking and overall character. analysing the well-log response several completely different channel forms can be identified. only the vertical continuity of the channel fill can be observed and almost nothing is known about their lateral dimensions and relationships. nevertheless, the position of the alluvial ridges or channel belts (in this case) can be estimated. examining the log shapes, several channel facies types have been differentiated. the first channel facies type (ecsegfalva) can be seen in fig. 3 i/a. the sedimentary sequence comprises multistorey, amalgamated or distinct channel fill deposits superimposed on each other, with a very small proportion of the fine-grained members like floodplain or oxbow lake deposits. the individual sandstone bodies are thick (10–20 m) with a sharp base and they have a cylindrical shape with a slight fining-upward tendency at the topmost part. they represent rather large rivers which were presumably possibly braided or slightly meandering in nature. the second type (csabacsüd ) can be seen in fig. 3 i/b. there are also stacked, multistorey channel fill deposits superimposed on each other with a small amount of fine-grained material in between. thus the depositional conditions were very similar but the sediments show a different pattern. the individual sandstone bodies are thinner and the fining-upward tendency is much more characteristic. above the channel fills – sometimes represented only by the coarser-grained channel lags – the proximal point bars appear, thus some of the sand bodies represent complete point bars. this indicates a meandering river style with 8–10 m deep channels. the third type (fig. 3/ii – dévaványa) appears as either a thinner or thicker, isolated, discrete channel fill sand body within the thick floodplain sedimentary succession. this is the most common channel type in the pleistocene sedimentary complex in the study area. although we can estimate the channel depth of the pre-existing rivers and also the fluvial style, the geometry of the channels (e.g. the width/thickness ratio) unfortunately cannot be determined on the basis of subsurface facies analysis. correlation between wells is rather uncertain in a fluvial environment due to the rapid lateral change of facies, even if the distance between the wells is only 1–2 km. when the wells are located very close to each other, the width of the channel belt may be estimated. point bar deposits point bar deposits are connected to meandering channel fills and have a characteristic shape on well logs. there is a succession of fining-upward tendencies that appear on the logs in the shape of a pine tree, with “branches” becoming finer and thinner upward. this is quite com174 geologia croatica 57/2 175juhász, müller & tóth-makk: alluvial architecture and fluvial cycles in quaternary deposits... mon in the sedimentary complex and generally overlies channel fill or channel lag deposits (fig. 3 i/b, ii). their thickness can reach 10 m. alluvial fan deposits (sandy sheet-flood deposits) deposits of the distal zone of an alluvial fan appear in a discrete area, and frequently comprise thin (3–5 m), medium and fine-grained sandstone beds interbedded with muddy deposits. the well-log looks extremely serrated without any characteristic tendency. this phenomenon can be observed in the eastern part of the study area, and represents sandy sheet-flood deposits and poorly defined sheet-like channel bodies interfingering with floodplain sediments. they were deposited in the far distal part of an alluvial fan formed in the foothills of the apuseni mountains (fig. 3/iv). fig. 3 characteristic facies associations and large-scale depositional elements in the alluvial succession of the körös basin. type i: different alluvial ridges or channel belts: (a) stacked, multistorey channel fills (braided river?), and (b) channel fill and point bar deposits (meandering river). high discharge, high sedimentation rates are common. type ii: proximal floodplain: single channel fills interbedded in the alluvial plain muds. thin sandy–silty beds as crevasse-splay, natural levee and flood-sheet deposits appear in the succession. type iii: distal alluvial plain and wetland (basin plain). type iv: distal part of an alluvial fan, sandy sheet-flood deposits, possible poorly defined sheet-like channels. 176 geologia croatica 57/2 177juhász, müller & tóth-makk: alluvial architecture and fluvial cycles in quaternary deposits... floodplain and floodbasin deposits floodbasin deposits include the fine-grained overbank sediments of the floodplain and cover a wide flat basinal area. the körös basin was probably a very flat area (as it is today), where several rivers flowed across the alluvial plain and their floodplains merged. part of the floodplain was either inundated by water for long periods during the year, or the groundwater-table was very high, leading to the formation of wetlands and also lakes in some areas. the maps of the area from the last century before regulation of the körös and berettyó rivers show these characteristics of this area. the floodbasin facies comprise the fine-grained overbank deposits of this deep-lying wide, flat basinal area. it is clearly stratified, with alternating silt and mud in the sedimentary succession, causing an extremely serrated well-log shape. in the proximal floodplain area, sandy channel fill deposits of variable thickness, crevasse splay and flood-sheet beds intercalate in the muddy succession. approaching the channel belts, the sandy facies becomes more frequent due to river avulsions. thinner sandy–silty beds the thinner (2–4 m thick) sandy–silty beds can be interpreted in a variety of ways in the absence of any evidence. therefore we tried to avoid their precise interpretation. they can be considered as thinner channels, natural levee or crevasse-splay deposits. they may also represent some sheet flood events depositing reworked sediments. the crevasse splay deposits appear as coarsening upward or massive sequences on the well-logs but the limited thickness of these beds and the resolution of the logs does not facilitate differentiation between these facies. 4.2. facies associations in the sedimentary complex of the körös basin the identified facies, as mentioned above, are vertically stacked in different successions and the following characteristic facies associations were distinguished. (1) type i facies association it is characterized by stacked, multistorey, amalgamated or distinct channel fills which either cut into each other or are incised into the underlying floodplain deposits (fig. 3/i). this association can comprise several superimposed channel fill sandstone bodies with thin intercalations of fine-grained deposits. thick, massive, clean sands with a sharp, erosive base can be identified from their log character. they represent superimposed major channel belts or alluvial ridges above each other either in a braided or meandering fluvial style, the latter with fining upward point bar deposits (figs. 3/ia and ib, respectively). the number of channels varies in this facies association, sometimes there is only one thin sandy channel. (2) type ii facies association this association is characterized by the alternation of discrete sandy channel fill and muddy floodplain deposits. the thickness is very variable. individual sandy facies (channel, point bar or crevasse splay deposits) can vary between 2–10 m in thickness. the facies association represents mainly the outer channel belt or the proximal floodplain area. this is the most common facies association in the körös basin. (3) type iii facies association the association is composed of silty–argillaceous floodplain and wetland deposits, sometimes with very thin isolated silt or sand bodies. these facies represent the aggrading sedimentary succession of the distal alluvial plain or the floodbasin. type iii muddy facies association or aggrading floodplain sediments may thin out or be completely absent in the channel belt while in other areas it can reach 80 m thickness. (4) type iv facies association the type iv association is characterized by 3–5 m thick frequently interbedded sand and mud successions. it is interpreted as sheet-flood deposits interbedded with muddy floodplain deposits and represents the deposits of the distal zone of an alluvial fan. thicker channel fills and thicker floodplain sediments in particular are missing. channels are poorly defined, and some parts of the succession could be interpreted as representing a terminal fan, or channels were found outside the study area. the overall thickness of this facies association with interbedded sand and clay lithofacies, varies between 20–300 m (fig. 3/iv). in the area of the alluvial ridges and in the proximal floodplain facies associations types i–iii overlie one another in succession in the studied quaternary fluvial sedimentary succession indicating an evolutionary development from fluvial channels to floodplain deposits suggesting cyclic deposition. the thickness of the different facies associations is highly variable. several cycles of this order can be recognized above each other in the observed quaternary sedimentary succession. 5. lithofacies distribution on the basin scale in a large area like the körös basin the stratigraphic record of the complex fluvial system varies through space and time. considering the general trends in the architecture of the körös basin, rather complex spatial variations can be recognized in the quaternary succession on the basin scale. different tendencies can be traced both vertically and horizontally which help to reconstruct the stratigraphic architecture of the basin. horizontally different lithofacies zones can be mapped where the quaternary series is more muddy or more sandy (i.e. the sand/mud ratio is lower or higher) than 176 geologia croatica 57/2 177juhász, müller & tóth-makk: alluvial architecture and fluvial cycles in quaternary deposits... the average for the basin. these variations are characterized on a basin scale and have major importance for the correlation of facies associations. a lithofacies distribution map for the overall quaternary succession in the study area is shown in fig. 4. four lithofacies zones were distinguished, a sandy zone, a sandy–muddy zone, a muddy zone and a frequent sand–clay alternation zone. there are also vertical trends in the succession therefore, e.g. the sandy lithofacies zone on the map does not necessarily mean that only the sediments of the channel belt can be found there. it means, however, that the sandy channel fill deposits are predominant. the boundaries of the lithofacies zones are gradual, they interfinger with one another. the sandy–muddy facies zone characterizes the largest area where normal fluvial successions of the proximal floodplain and the marginal parts of the channel-belt are intercalated. this zone is characterized by a type ii facies association, a typical sedimentary succession of which is shown in fig. 5. further away from the channel belt the number and thickness of the channel sands decreases. there are several areas however where the succession is different. in the n, w and s margins of the basin the sandy lithofacies zone can be detected where type i facies associations with stacked, multistorey channel fill deposits are characteristic, i.e. superimposed channel belts, with high net-to-gross ratio1, or with rather small proportion of the fine-grained deposits throughout the whole quaternary succession (fig. 6). the three sandy zones presumably represent the main channel belts or alluvial ridges. larger rivers just entered the study area and then left it. it is worth mentioning that larger rivers are not found along the axis of the basin in the deepest part where one would expect the course of the rivers to be, but they occur on higher areas surrounding the central parts which is the subject of ongoing investigations. their continuity is not indicated due to a lack of data in the interconnecting areas. in the central part of the area a muddy facies zone was distinguished where the sedimentary succession is composed of mainly fine-grained deposits (fig. 7). it is largely characterized by type iii facies associations of the distal basin plain. the area of this zone was a morphological low where subsidence was stronger than in the surroundings as indicated on the isopach map of the quaternary sediments, which means also at the structural contour map at the base of the pleistocene as the surface is almost totally flat now (fig. 2). therefore the preservation potential was higher and a thicker alluvial succession can be found here. this facies zone fig. 4 lithofacies distribution zones in the körös basin. the boundaries are gradual, different zones interfinger with each other, and are variable vertically. legend: 1) sandy–muddy zone: proximal floodplain; 2) frequent interbedded sand–mud zone: distal part of an alluvial fan, sandy flood-sheets; 3) sandy zone: main channel belts, alluvial ridges; 4) muddy zone: wetland, floodbasin; 5) studied profile; 6) well; 7) cited well; 8) cored well; 9) settlement; 10) pond, 11) cited profile. 1 net-to-gross ratio: an oil-industry term referring to the ratio of net sands to the whole succession. 178 geologia croatica 57/2 179juhász, müller & tóth-makk: alluvial architecture and fluvial cycles in quaternary deposits... is comprised of mostly clayey and silty floodplain and presumably wetland and occasional lacustrine deposits (fig. 7). the water table may have been very high in this area and only a very few, thin sandy channel fill sandstone bodies can be found interbedded in the thick floodbasin succession. the base and the uppermost part of the succession, however, consist of some channel fill sands, the latter depicting the time when the sebes– körös arrived in the area where it flows even today. in the eastern part of the körös basin this muddy facies zone intertongues with a sedimentary succession characterized by frequent, rather thin sandstone bodies intercalated with floodplain deposits (figs. 4 and 8). it corresponds to sandy sheet floods of the distal zone of an alluvial fan (type iv facies association), occurring approximately along the course of the present day sebes–körös. the thickness of this type of facies is changeable within this zone. in some wells it can be 300 m thick, while in other wells it is only 50 m and sediments of the distal and proximal floodplain underlie it or intercalate with it. in the topmost part, channel fills appear indicating a proximal floodplain environment. an overall vertical variation was also recognized in the basin, which is superimposed on the horizontal changes. although the pleistocene sedimentary succession starts with a laterally extensive sand bed (amalgamated channel sand or sand sheet) a few metres thick in all parts of the körös basin, during early pleistocene times sediments were finer-grained on a basin scale. more floodplain sediments occur in the lowermost part of the sequence. in the middle parts of the sedimentary succession sandy facies become more prevalent in a few areas. in the uppermost 150–200 m, however, sediments become much more sandy, channel fill beds can be detected in all parts of the basin, even in the muddy facies zone. fig. 5 characteristic sedimentary succession in the sandy–muddy lithofacies zone, representing the proximal floodplain area (detail). from time to time smaller or larger channels cut through it. 178 geologia croatica 57/2 179juhász, müller & tóth-makk: alluvial architecture and fluvial cycles in quaternary deposits... on the basis of the facies map of the basin at least three separate fluvial systems can be identified. the sand zones pinpoint the depositional axes of the channel belts. the sandy facies zones in the n and s were probably parts of the main channel belts of two distinct river courses, probably the ancient tisza in the n and w considering the large channel sizes, and the ancient körös in the s. the sandy facies zone in the w may be a continuation of one of them or their confluence. an alluvial fan system can be recognized in the eastern area of the basin with the sandy sheet-flood characteristics of the distal zone which interfinger with the muddy wetland zone towards the centre of the basin. 6. sequence-stratigraphic framework – a first assessment the studied quaternary sedimentary succession represents a maximum time range of 2.6 ma. any kind of subdivision results in tens of thousand to hundreds of thousand year cycles, i.e. fourth to fifth-order cycles. vail et al. (1991) restricted the term “depositional sequences” to the so-called third-order eustatic cycles of 0.5–3 ma time scale. later posamentier et al. (1992) pointed out that sequence stratigraphic concepts are time and scale independent. the terms cycles and sequences were often interchanged on the scale of the milankovitch frequency band, as sea-level changes were also controlled by climatic cycles in this time-frame. the original sequence stratigraphic terminology used fig. 6 characteristic sedimentary succession in the sandy lithofacies zone, representing the area of a channel belt or alluvial ridge (detail). 180 geologia croatica 57/2 181juhász, müller & tóth-makk: alluvial architecture and fluvial cycles in quaternary deposits... parasequences for the 4th to 5th order frequencies, during interpretation of carbonate and fluvial sedimentary successions the authors often use cycles. as our time range during the quaternary refers to the milankovitch frequency band (short-term, 5th order, and long-term, 4th order cycles) we prefer the term cycles here to sequences, and cycle boundary (cb) to sequence boundary, though the identified cycles could well have been sequences. as for the subdivision of individual cycles, the sequence stratigraphic terminology is not really relevant to fluvial sequences and different terms seem to be very artificial in usage. in this interpretation we refer to the terminology introduced by weissmann et al. (2002) on the basis of blum & törnqvist (2000). therefore we use the terms low-, increasingand high-accumulation space deposits for systems tract terminology which can correspond to lowstand, transgressive and highstand systems tracts respectively. 6.1. a brief review of various concepts and terminology on the fluvial response to climate change in continental basins the basic concepts of sequence stratigraphy were established and applied mainly for coastal and marine sequences (vail et al., 1977; posamentier et al., 1988; van wagoner et al., 1988, 1990; posamentier & allen, 1991). most of the examples for terrestrial sequence stratigraphy were taken from large coastal plains where sequence boundaries could be correlated from the shallow marine area, and base-level control through eustatic control was emphasised. only very few attempts were made to apply the basic concepts to terrestrial strata. the application of sequence fig. 7 characteristic sedimentary succession in the muddy lithofacies zone, representing the floodbasin or wetland area. channels can be observed at the base and the uppermost part of the quaternary. thinner or thicker muddy intercalations within the succession are common. 180 geologia croatica 57/2 181juhász, müller & tóth-makk: alluvial architecture and fluvial cycles in quaternary deposits... stratigraphic principles to terrestrial successions beyond the influence of sea-level, was considered to be in its “infancy” (shanley & mccabe, 1994). the most serious limitation for short term progress in terrestrial sequences, especially interior basins, is the relative scarcity of well-documented actual examples studied from a sequence stratigraphic perspective (legarreta & uliana, 1998). the main problems in terrestrial sequences include defining the role of tectonics, the usage of terminology which is still confusing, and the discrimination of autocyclic and allocyclic phenomena. in thick fluvial successions the crucial point in the recognition and interpretation of allocyclic processes is to find regionally extensive and correlatable erosional surfaces. flowing across a plain, a river can respond to base-level change by adjusting the channel pattern, width, depth and roughness and (only if the change is very large) by incision, but the rate of change is of great importance (schumm, 1993). the first comprehensive review of sequence stratigraphic models for continental strata was published by shanley & mccabe (1994). they discussed a larger scale architectural pattern and systematic variations in the controlling processes focusing on the effects of accommodation space and sediment supply. they use the term accommodation space for continental strata, and also stratigraphic base level as the local groundwater tables which reflect regional potentiometric surfaces. they stated that in interior basins recognition of alluvial sequence boundaries rests almost entirely on changes in alluvial stacking patterns. they stated that multilateral, multistorey channel units were often thought by many authors to represent low rates of stratigraphic base level fig. 8 characteristic sedimentary succession in the zone of the frequent interbedded sand–mud lithofacies. sandy flood-sheets and poorly defined, sheetlike channel bodies represent the area of the distal zone of an alluvial fan. 182 geologia croatica 57/2 183juhász, müller & tóth-makk: alluvial architecture and fluvial cycles in quaternary deposits... rise and to overlie sequence boundaries associated with allocyclic phenomena. perhaps one of the best case studies for continental interior (hinterland) basins, and providing a useful model is that of legarreta & uliana (1998) on upper cretaceous fluvial strata in argentina. they introduce new sequence stratigraphic terms for a terminating desert fluvial system. in a thick fluvial succession they found the repeated appearance of sandy forward stepping stacks, followed by sandy– shaly backstepping complexes and mudstone-rich aggradational stacks which was a common depositional motif in some hinterland basins dominated by alluvial infilling. these stacks or complexes correspond to the systems tracts of a marine sequence. the basinward and also the backward shift of the depositional system could be followed. a concept ‘base profile’ was proposed representing the continental extension of base level by quirk (1996). it is defined as the ideal graded profile of a drainage basin at a specific moment. rivers tend to aggrade up or degrade down to base profile, so it describes changes in accommodation space. new accommodation space is created by the rise of base profile and degradation happens if there is a fall in base profile. the concept, however, has not come into use. the shortcomings of the previous and current models were summarized by ethridge et al. (1998), who dealt with the problems and perspectives of the cyclic variables controlling fluvial sequence development and the difficulties of distinguishing various controls. the usage of cycles of different scales at the same time, are rather rare in practice. in the context of carbonate systems, not fluvial cycles, strasser et al. (1999) show a hierarchical stacking of depositional sequences, and define small-scale, medium-scale and large-scale sequences. they speak about sequences and not cycles in the milankovitch frequency band. a complete and comprehensive literature review, together with comprehensive predictions of fluvial responses to climate and sea-level change based on quaternary and pre-quaternary records, was given by blum & törnqvist (2000). they differentiate three types of fluvial responses: stratigraphic, morphological and sedimentological. stratigraphic responses are caused by aggradation, degradation and lateral migration, and produce cycles or sequences which reflect allogenic controls. they concluded that fluvial systems in subsiding basins are characterized by longterm net aggradation, punctuated by relatively short periods of incision and/or lateral migration. morphological responses reflect changes in channel geometry. sedimentological responses can be viewed within the context of alluvial architecture, as the geometry, proportion and spatial distribution of different types of fluvial deposits. they introduced the terms accumulation space and preservation space. as to the preservation potential, the role of basin subsidence is very important. they emphasized the importance of palaeosol-bounded floodplain facies. they also provide a broad range of case studies in the paper and state that there is a particular need for studies on this theme. in their summary they describe a general stacking pattern that is the amalgamated high net-to-gross channel belts that rest on what is interpreted to be a sequence boundary and overlain by isolated ribbon-like sand bodies. these are encased in laterally extensive mudstone dominated successions. in terms of non-marine sediments plint et al. (2001) use the terminology of low-accomodation and high-accomodation system tracts. weissmann et al. (2002) interpreted an alluvial fan succession in terms of accumulation space cycles driven by glacial climate changes. they introduced the terms low-, increasing and high-accumulation space deposits for systems tract terminology in a purely alluvial system, which up-tonow seems to be the best for characterizing the different fluvial processes and depositional units, and it is therefore applied in the following sections. 6.2. depositional cycles in the quaternary succession of the körös basin the körös basin is a continental interior basin which has existed since the pliocene. the four modern transverse rivers draining the apuseni mountains and their alluvial plain form a floodbasin rather than a floodplain, as it is a wide and extremely flat area. before the regulation of these rivers at the end of the 19th century, almost the entire area was covered by water during flood periods and to a lesser extent under normal conditions. the area is presently distant from the black sea as it was during the quaternary, and in this respect conditions were presumably very similar to the present-day. therefore the main allogenic factors controlling the architecture and morphology of the alluvial complex of the körös basin may have been climate and tectonics, as well as changes in local base level and sediment supply which are both connected to the previous factors. tectonics was responsible both for the subsidence of the basin and uplift of the hinterland in the apuseni mountains. climate influenced sedimentation through sediment supply, discharge variability as well as vegetation. it is rather difficult to unravel the effect of the various controlling factors. most authors’ work and most models are based on eustatic (base level) changes or consider only one controlling factor. in fact there is a complex interplay between these factors. most of the literature cited above agrees on the importance of recognizing stacking patterns in the alluvial sequences. in interior basins, recognition of alluvial sequence boundaries rests almost entirely on changes in alluvial stacking patterns (shanley & mccabe, 1994). multilateral (amalgamated), multistorey channel units are often thought by many authors to represent low rates of stratigraphic base level rise and to overlie sequence boundaries associated with allocyclic phenomena (posamentier et al., 1988; shanley & mccabe, 1994; aitken & flint, 182 geologia croatica 57/2 183juhász, müller & tóth-makk: alluvial architecture and fluvial cycles in quaternary deposits... 1995; legarreta & uliana, 1998). according to different authors, local base level is referred to as stratigraphic base level (shanley & mccabe, 1994), or base profile (quirk, 2000), and all of them have a slightly different approach to this. the sand bodies become more isolated upward and the succession is terminated by aggrading floodplain sediments. the quaternary of the körös basin started with a period of erosion as shown in most of the studied wells, which resulted in an unconformity truncating the pliocene alluvial succession. in many wells, fining-upward cycles can be repeatedly observed in parts of the studied quaternary sedimentary succession in the körös basin (fig. 9). in the alluvial ridge and in the proximal floodplain, the different recognized facies associations discussed in the sedimentological sections are superimposed into a vertical pattern which shows that they form a sedimentary cycle in this order. they indicate a successive evolution from fluvial channels to floodplain and wetland deposits. the different “systems tracts” can also be defined in this cycle or sequence. the basal member of the cycle comprises a type i facies association with stacked multistorey channel fills and with hardly any fine-grained intercalations, and it represents the low-accumulation space deposits (“lowstand or early transgressive systems tract” in the sequence stratigraphic terminology). this means that during this period the rivers adjusted their course and fluvial style to the changing conditions by lateral migration. the thickness of this unit can vary between 0–50 m. in the muddy facies zone or the wetland area (see facies map on fig. 4) low-accumulation space deposits may be represented by only one single channel fill body, or may be completely absent. the intermediate member of the cycle is represented mainly by the type ii facies association, and is built up by 5–20 metre thick alternating sand and mud beds. this reflects increasing-accommodation due to a rise in the ground-water table/stratigraphic base level or caused by basin subsidence. alternatively, it can reflect a decreasing sedimentation rate. it represents the increasingaccumulation space deposits (“transgressive systems tracts” in sequence stratigraphic terms). the upper member of the cycle is built up by a type iii facies association comprising thicker or thinner floodplain deposits with no or very few isolated thin sandstone–siltstone intercalations. it represents aggradation and the high-accumulation space deposits (“highstand systems tract”). in the terminology of legarreta & uliana (1998) it is called the aggradational systems tract which is the best expression for this unit. in some places this aggrading unit was thinned out or completely eroded by the overlying channel system. its thickness is variable, it can reach 50–60 m, but it can be eroded completely. the above ideal depositional cycle shows up in an extremely varying form in the basin depending on the environment where it was formed. therefore the general lithofacies map can reveal a lot about the succession. there are areas where the cycles are not complete. in fig. 9 an ideal depositional cycle in the quaternary fluvial succession. legend: has – high-accumulation space; ias – increasing-accumulation space; las – low-accumulation space; cb – cycle boundary. terminology: see in text. 184 geologia croatica 57/2 185juhász, müller & tóth-makk: alluvial architecture and fluvial cycles in quaternary deposits... the channel belt, the upper and maybe the intermediate member of the cycle could be eroded or it was not formed at all. moving away from it towards the proximal and distal floodplain the thickness of the basal member gradually decreases. in the area of the floodbasin the lower and intermediate member of the cycle can be represented by a thin single sand or silt bed. in the muddy facies zone the identification and correlation of the depositional cycles seem to be problematic and dubious. the above cycles are demonstrated in two wells. the first represents the sandy–muddy facies zone, or proximal floodplain on the facies map (fig. 10). the appearance of the cycles is easily detectable, and three cycles can be observed above each other, but this does not represent the whole quaternary succession. sand bodies show systematic changes in thickness, and the fining upward stacking pattern is clear, showing the different facies associations discussed above. the second well is located in the sandy lithofacies zone, or channel belt, penetrating the whole quaternary succession and all the identified cycles are shown (fig. 11). the succession is much more sandy but incision did not entirely remove the uppermost member of the cycles, the aggrading floodplain or high-accumulation space deposits (“highstand systems tract”). consequently we may assume that every cycle was recorded and the cycles can be figured out and identified properly. in this fig. 10 sequence stratigraphic interpretation of a well in the proximal floodplain zone (detail). legend: has – highaccumulation space; ias – increasingaccumulation space; las – low-accumulation space; cb – cycle boundary. terminology: see in text. 184 geologia croatica 57/2 185juhász, müller & tóth-makk: alluvial architecture and fluvial cycles in quaternary deposits... well, which represents the whole quaternary succession, six successive cycles could be recognized. we do not know precisely the allocyclic controlling factors of these cycles, but the fact that there are six cycles in the succession representing the whole quaternary (2.6 ma) suggests orbital forcing in the milankovitch frequency band, most probably the 400 ka long eccentricity cycles. however, even if they were driven by climatic changes they were also influenced by tectonic forces through their thickness and internal architecture. bundles of short-term fining-upward cycles can also be traced in certain wells or areas but they are not correlatable either regionally or over long distances. 7. correlation correlation in a fluvial sedimentary succession is always dubious or uncertain as the discontinuous nature of alluvial strata makes it difficult. for this reason, large-scale, basin-wide correlation is not a matter of sedimentology but belongs to the subject of cycle or sequence stratigraphy. differentiation between allocylic and autocyclic phenomena is rather difficult. finding regionally extensive erosional surfaces, which were driven by allocyclic phenomena, is the key to the correlation of fluvial strata. the identified large-scale cycles in this study represent several 100 ky of deposition. the long-term (4th order) milankovitch-cycles are also of this time fig. 11 six large-scale, approx. 400 ka milankovitch cycles and sequence stratigraphic interpretation of a well in the channel belt. legend: has – highaccumulation space; ias – increasingaccumulation space; las – low-accumulation space; cb – cycle boundary. terminology: see in text. 186 geologia croatica 57/2 187juhász, müller & tóth-makk: alluvial architecture and fluvial cycles in quaternary deposits... fig. 12 sedimentological and sequence stratigraphic cross section through the quaternary facies zones. shifting of the facies zones can be observed through time. legend: see on fig. 4. -n n i j i j j i i ~ i f ! i 186 geologia croatica 57/2 187juhász, müller & tóth-makk: alluvial architecture and fluvial cycles in quaternary deposits... duration. deposits of this scale are typically regionally extensive and are mappable. during this time interval the generation and abandonment of entire depositional systems may be accomplished (miall, 1996). correlation of the identified large-scale cycles was carried out along the geological and stratigraphic profiles indicated on fig. 4. sedimentological correlation of the main lithofacies zones can be seen on a regional profile on fig. 12, where the shift of the facies zones can be detected in time. alternatively, sequence stratigraphic correlation between the studied wells can be detected throughout the whole basin. correlation is easy in some areas, i.e. in the areas of the sandy and sandy–muddy facies zones, or through the channel belt zone and the “proximal” floodplain zone, but is difficult in the muddy facies zone, or in the wetland. dashed lines represent interpolations in the ambiguous parts. there are questions about the correlation in the e part of the basin where the distal alluvial fan sediments were found. on the sedimentological profile in this zone we can see the forestepping and backstepping nature of the distal fan system, causing coarseningand thickening-upward, and finingand thinning-upward trends of the sand bodies in the upper 300 m of the studied wells (fig. 13). in some wells shorter-term cycles can be seen either in the fluvial or in the alluvial successions, which makes the overall pattern a little confused, but these cycles cannot be traced regionally. 8. discussion sediments described here were finer-grained in the lower part of the pleistocene succession on the basin scale in the study area. more floodplain deposits can be found in the lowermost part of the sequence while the sandy facies become more prevalent upwards in a few areas. in the uppermost 150–200 m, however, sediments become much more sandy, channel fill beds can be detected even in the muddy facies zone. this corresponds to the results of recent provenance studies and tectonic models of the area (thamóné bozsó & kercsmár, 2000; thamó-bozsó et al., 2002). these revealed changes of transport directions at about 1.95 ma related to significant changes in the uplift history of the apuseni mountains catchment fig. 13 geological cross section in the e part of the koros basin. the uppermost 300 m on the profile was deposited as flood-sheets intercalated by floodplain deposits in the distal fan zone. the forestepping and backstepping of the system can be clearly observed. the lower part was deposited under normal fluvial conditions. 188 geologia croatica 57/2 189juhász, müller & tóth-makk: alluvial architecture and fluvial cycles in quaternary deposits... area. earlier sediment supply came from a ne direction while a synsedimentary trap was formed inbetween the apuseni mountains and the study area. this probably caused the sedimentation of fine-grained deposits in the lower part of the succession. after this time tectonic events resulted in the infilling of the trap and the development of transverse drainage characterized by se transport directions and an increased sediment flux. at this time an alluvial fan reached the area of the körös basin from the emerging apuseni mountains and is well represented in the sedimentary succession in fig. 8. the cyclic nature of the quaternary sedimentary succession in the körös basin was studied recently in two boreholes with continuous cores. the dévaványa and vésztő boreholes are located in the central part of the körös basin, one in the muddy facies zone, and the other in the sandy–muddy facies distribution zone (fig. 4). different parameters (average grain size, magnetic susceptibility, palaeontological data) show cyclic changes in the boreholes. it was pointed out that a 40 ka cyclicity characterizes the older pleistocene (greater than 1 ma), while 100 ka cyclicity occurs in the younger pleistocene. a remarkably good correlation was found between these data and the oxygen isotope variations of the marine odp 677 site, suggesting continuous sedimentation in the basin, at least on the scale of the above mentioned milankovitch cycles (nádor et al., 2000, 2003). in the present study, well-logs used for interpretation and correlation provided a larger-scale approach. for this reason the above mentioned high-frequency cycles cannot be recognized, although in some places traces of them were detected. in the upper two largescale cycles, however, where the 100 ky cycles were prevalent, they can possibly be detected on the logs, disturbing the interpretation on a basin scale. six large-scale cycles were recognized in the sedimentary succession. at this stage there is no firm evidence of whether these cycles were driven by climatic or tectonic forces. taking into account the quasi continuity of the sedimentary succession in the körös basin, estimation of the time range suggests 400 ka cycles in the milankovitch frequency band (4th order cycles). a good correlation of the present study with previous results of the continuous cores can be assumed by the fact that the uppermost two large-scale cycles correspond to the interval where nádor et al. (2000) identified the 100 ka periodicity medium-scale cycles. the lower boundary of the second large-scale cycle from above lies on the boundary where the cyclicity changes from 40 to 100 ka in the high-frequency investigations. 9. conclusions (1) based on the interpretation of the different alluvial depositional elements in the quaternary succession of the körös basin various depositional facies, and four types of facies associations were defined. (2) a basin-scale facies map of the study area was drawn. besides the average fluvial architecture (where single channel sands alternate with alluvial plain muds), three areas were depicted where the multistorey stacked sandy channel fill sediments are predominant indicating pre-existing channel belts. in the central part of the basin, probably representing the deepest areas, muddy sediments of the floodplain and a probable wetland are prevalent. in the e part of the basin sediments of the distal part of an alluvial fan alternate with floodplain deposits. (3) the characteristic facies associations overlying one another in succession indicate a fining-upward fluvial depositional cycle on a scale of several tens of metres. on a regional scale, six cycles were recognized in the quaternary succession. the base of the cycles is an extensive erosional surface which can be correlated regionally across the basin. the cycles are probably allocyclic but the question of whether they were tectonically or climatically driven has not been firmly proven. the fact however, that six cycles have been identified in an approximately 2.6 ma quaternary interval, suggests that they are 400 ka large-scale milankovitch cycles. the tectonic overprint can be detected in the thickness and internal architecture of the individual cycles. (4) internally, the structure of the cycles was subdivided into three units. the basal stacked multistorey, multilateral channels form the low-accumulation space deposits. the alternation of channel and floodplain sediments above comprises the increasing-accumulation space deposits. at the topmost part of the cycle the aggrading floodplain muds and silts of the highaccumulation space deposits can be found. these units correspond to the lowstand, transgressive and highstand systems tracts in sequence stratigraphic terms, respectively. (5) correlation through the wetland, i.e. the central part of the study area has not been entirely solved. compilation of the correlation throughout the whole basin is one of the main goals for future studies. it would be important to determine the facies distributions on a cycle scale and thus to define palaeogeographic maps and interpret individual cycles. acknowledgements this work has been funded by the hungarian national scientific research fund (otka t–32956). we would like to thank a. nádor, o. sztanó and j. haas 188 geologia croatica 57/2 189juhász, müller & tóth-makk: alluvial architecture and fluvial cycles in quaternary deposits... for their useful advice and m. kovac, j. velić and j. tišljar for their kind review of the paper and their valuable remarks. 10. references aitken, j.f. & flint, s.s. (1995): the application of high resolution sequence stratigraphy to fluvial systems: a case study from the upper carboniferous breathitt group, eastern kentucky, usa.– sedimentology, 42, 3–30. bérczi, i. & phillips, r.l. (1985): processes and depositional environments within neogene deltaic–lacustrine sediments, pannonian basin, southeastern hungary.– geophysical transactions, spec. ed., 71–87. blum, m.d. & törnqvist, t.e. (2000): fluvial responses to climate and sea-level change: a review and look forward.– sedimentology, 47 (suppl.1), 2–48. borsy, z. (1992): evolution of the alluvial fans of the alföld.– in: rachocki, a.h. & church, m. (eds.): alluvial fans: a field approach. john wiley & sons ltd., 452 p. cooke, h.b.s., hall, j.m. & rónai, a. (1979): paleomagnetic, sedimentary and climatic records from boreholes at dévaványa and vésztő, hungary.– acta geol. hung., 22, 89–109, budapest. ethridge, f.g., wood, l.j. & schumm, s.a. (1998): cyclic variables controlling fluvial sequence development: problems and perspectives.– in: shanley, k.w. & mccabe, p.j. (eds.): relative role of eustacy, climate and tectonics in continental rocks. soc. econ. paleont. miner. spec. publ., 59, 17–29. horváth, f. & cloetingh, s. (1996): stress induced late-stage subsidence anomalies in the pannonian basin.– in: cloetingh, s., ben avraham, z., sassi, w. & horváth, f. (eds.): dynamics of extensional basins and inversion tectonics. tectonophysics, 266, 287–300. juhász, gy. (1991): sedimentological and lithostratigraphical framework of the pannonian (s.l.) sequence in the hungarian plain, eastern hungary.– acta geol. hung., 34/1–2, 53–72, budapest. juhász, gy. (1994): comparison of the sedimentary sequences in late neogene subbasins in the pannonian basin, hungary (magyarországi neogén medencerészek pannóniai s.l. üledéksorának összehasonlító elemzése).– földtani közlöny, 124/4, 341–365, budapest. legarreta, l. & uliana, m.a. (1998): anatomy of hinterland depositional sequences: upper cretaceous fluvial strata, neuquen basin, west–central argentina.– in: shanley, k.w. & mccabe, p.j. (eds.): relative role of eustacy, climate and tectonics in continental rocks. soc. econ. paleont. miner. spec. publ., 59, 83–91. miall, a.d. (1996): the geology of fluvial deposits.– springer-verlag, new york, heidelberg, berlin, 582 p. miall, a.d. (2002): architecture and sequence stratigraphy of pleistocene fluvial systems in the malay basin, based on seismic time-slice analysis.– am. assoc. petrol. geol. bull., 86/7, 1201–1216. miháltz-faragó, m. (1982): tiszántúli alapfúrások palinológiai vizsgálata [palinological examinations of full-cored wells in the trans-tisza area – in hungarian].– máfi évi jelentése 1980-ról., 103–120, budapest. molnár, b. (1973): az alföld harmadidőszak végi és negyedkori feltöltődési ciklusai [depositional cycles in the quaternary and late tertiary in the hungarian plain – in hungarian].– földtani közlöny, 103/3–4, 294–310, budapest. nádor, a., müller, p., lantos, m., thamóné bozsó, e., kercsmár, zs., tóthné makk, á., sümegi, p., farkasné bulla, j. & nagy, t. (2000): a klimaváltozások és az üledékes ciklusok kapcsolata a körös-medence negyedidőszaki folyóvizi rétegsoraiban [climate controlled sedimentary cycles in the quaternary fluvial sequence of the körös-basin – in hungarian].– földtani közlöny, 130, 623–645, budapest. nádor, a., lantos, m. & thamó-bozsó, e. (2003): milanković-scale multi-proxy records from fluvial sediments of the last 2.6 ma, pannonian basin, hungary.– quater. sci. rev., 22, 2157–2175. nagymarosy, a. & müller, p. (1988): some aspects of neogene biostratigraphy in the pannonian basin.– in: royden, l. & horváth, f. (eds.): the pannonian basin: a study in basin evolution. am. assoc. petrol. geol. memoir, 45, 69–77. pirson, j. (1970): geologic well-log analysis.– gulf publishing co., houston, 370 p. plint, a.g., mccarthy, p.j. & faccini, u.f. (2001): nonmarine sequence stratigraphy: updip expressions of sequence boundaries and systems tracts in a high resolution framework, cenomanian dunvegan formation, alberta foreland basin, canada.– am. assoc. petrol. geol. bull., 85/11, 1967–2001. posamentier, h.w. & allen, g.p. (1991): the effects of base level control on sedimentation patterns in the fluvial/coastal plain environment.– geol. soc. am. annual meeting, san diego, abstracts, 53. posamentier, h.w., jervey, m.t. & vail, p.r. (1988): eustatic controls on clastic deposition i – conceptual framework.– in: wilgus, c.k., hastings, b.j., posamentier, h.w., van wagoner, j.c, ross, c.a. & kendall, c.g. (eds.): sea-level changes: an integrated approach. soc. econ. paleont. miner. spec. publ., 42., 109–124. posamentier, h.w., allen, g.p., james, d.p. & tesson, m. (1992): forced regressions in a sequence stratigraphic framework: concepts, examples and exploration significance.– am. assoc. petrol. geol. bull., 76/11, 1687–1709. quirk, d. (1996): base profile: a unifying concept in alluvial sequence stratigraphy.– in: howell, j.a. & aitken, j.f. (eds.): high resolution sequence stratigraphy: innovations and applications. geological society spec. publ., 104, 37–49. rónai, a. (1985): az alföld negyedidőszaki földtana [the quaternary geology of the hungarian plain – in hungarian].– geol. hung., series geologica, 21, 446 p. royden, l. & horváth, f. (eds.) (1988): the pannonian basin: a study in basin evolution.– am. assoc. petrol. geol. memoir, 45, 394 p. 190 geologia croatica 57/2 schumm, s.a. (1993): river response to base-level change: implications to sequence stratigraphy.– jour. geol., 101, 279–294. serra, o. (1985): sedimentary environments from wireline logs.– schlumberger, montrouge, 211 p. shanley, k.w. & mccabe, p.j. (1994): perspectives on the sequence stratigraphy of continental strata.– am. assoc. petrol. geol. bulletin, 78/4, 544–568. shanley, k.w. & mccabe, p.j. (eds.) (1998): relative role of eustacy, climate and tectonics in continental rocks. soc. econ. paleont. miner. spec. publ., 59, 234 p. strasser, a., pittet, b., hillgartner, h. & pasquier, j.b. (1999): depositional sequences in shallow carbonate dominated sedimentary systems: concepts for high-resolution analysis.– sed. geol., 128, 201–221. thamóné bozsó, e. & kercsmár, zs. (2000): a körös-medence negyedidőszaki beszállítási irányainak változása a képződmények ásványi összetétele és a tektonikai háttéresemények alapján [changes of transport direction into the körös basin during the quaternary – in hungarian].– földtani közlöny, 130/4, 647–671, budapest. thamó-bozsó, e., kercsmár, zs. & nádor, a. (2002): tectonic control on changes in sediment supply: quaternary alluvial systems, körös sub-basin, se hungary.– in: jones, s.j. & frostick, l.e. (eds.): sediment flux to basins: causes, controls and consequences. geol. society london, spec. publ., 191, 39–53. vail, p.r., mitchum, r.m. & thompson, s. (1977): seismic stratigraphy and global changes of sea-level.– in: payton, c.w. (ed.): seismic stratigraphy – application to hydrocarbon exploration. am. assoc. petrol. geol. memoir, 26, 49–212. vail, p.r., audemard, f., bowman, s.a., eisner, p.n. & perez-cruz, c. (1991): the stratigraphic signature of tectonics, eustacy and sedimentology – an overview.– in: einsele, g., ricken, w. & seilacher, a. (eds): cycles and events in stratigraphy. springerverlag, new york, heidelberg, berlin, 617–659. van wagoner, j.c., posamentier, h.w., mitchum, r.m., vail, p.r., sarg, j.f., loutit, t.s. & hardenbol, j. (1988): an overview of the fundamentals of sequence stratigraphy and key definitions.– in: wilgus, c.k., hastings, b.j., posamentier, h.w., van wagoner, j.c, ross, c.a. & kendall, c.g. (eds.): sea-level changes: an integrated approach. soc. econ. paleont. miner. spec. publ., 42, 39–46. van wagoner, j.c., mitchum, r.m., campion, k.m. & rahmanian, v.d. (1990): siliciclastic sequence stratigraphy in well-logs, cores and outcrops.– am. assoc. petrol. geol. methods in exploration series, 7, 55 p. weissmann, g.s., mount, j.f. & fogg, g.e. (2002): glacially driven cycles in accumulation space and sequence stratigraphy of a stream-dominated alluvial fan, san joaquin valley, california, usa.– jour. sed. res., 72/2, 240–251. manuscript received october 20, 2003. revised manuscript accepted november 08, 2004. sokač et al.: taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia) 161  ab stra ct a rich algal assemblage at the kozica locality, in the northern foothills of mt. biokovo, contains, among other forms, praturlonella salernitana barattolo. in addition, the descriptions of clypeina bucuri barattolo & romano and c. lucana barattolo & romano are updated, and the originally described clypeina teakolarae radoičić et al. has been tentatively transferred to the genus falsolikanella granier as falsolikanella? tea­ kolarae n. comb. falsolikanella? macropora n. sp. is described, characterized by probable metaspondyle growth of clearly phloiophorous branches, differentiated individually into a narrow stalk and very long, markedly widened, outer part. based on the algal assemblage as a whole, together with benthic and planktonic foraminifers, the stratigraphic position of the algal-bearing level has been defined as ypresian (lowermost eocene). keywords: calcareous algae (dasycladales), taxonomy, stratigraphy, eocene, dinarides, croatia taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia)  branko sokač1, ivo velić2, tonći grgasović1, vlasta ćosović3 and igor vlahović4 1 croatian geological survey, sachsova 2, p.o. box 268, hr-10000 zagreb, croatia; (tgrgasovic@hgi-cgs.hr) 2 pančićeva 5, hr-10000 zagreb, croatia; (ivo.velic@zg.t-com.hr) 3 university of zagreb, faculty of science, horvatovac 102a, hr-10000 zagreb, croatia; (vcosovic@geol.pmf.hr) 4 university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, hr-10000 zagreb, croatia; (igor.vlahovic@rgn.hr) doi: 104154/gc.2012.11 geologia croatica 65/2 161–205 2 figs. 19 pls. zagreb 2012 geologia croaticageologia croatica 1. introduction rare discoveries of dasyclad algae in the lower part of palaeogene deposits along the coastal region of the karst dinarides in croatia, are limited to several localities, according to the data published so far, either as a result of random sampling or samples being handed over to the authors by colleagues. initial finds from southern dalmatia are mentioned in radoičić’s (1974) description of actinoporella kukoci from the tri luke locality on the island of korčula, supposedly of palaeocene age. later, radoičić (1995) reconsidered the stratigraphic position of beds with a. kukoci and rare fragments of praturlonella salernitana barattolo on korčula and the neighbouring pelješac peninsula. she concluded, on the basis of the accompanying foraminiferal assemblage and its occurrence at the other localities (apennines, istria), that it was middle-to-late eocene in age, and not older than the middle lutetian. later still, radoičić (2004) reports on the rich algal assemblage (more than 20 species) in a sample from the pločice locality, (the area of konavle, se of dubrovnik), coming from a calcareous-dolomitic zone, ascribed previously to the maastrichtian– danian stratigraphic range. the author stresses the significance of that find and, though lacking the analysis of the stratigraphic column, concludes, on the basis of the algal assemblage, on its danian age, this being as yet the oldest documented palaeogene strata in this area. in the course of field investigations carried out during biostratigraphic analysis of foraminiferal assemblages in the jurassic and cretaceous carbonate platform deposits of the croatian dinarides (velić, 2007), a section cutting through geologia croatica 65/2geologia croatica 162 2. stratigraphic position of the algalbearing deposits in the kozica stratigraphic column the ancient adriatic carbonate platform (adcp) disintegrated into several blocks during the late cretaceous (see e.g. vlahović et al., 2005; korbar, 2009 and references therein) which emerged at different times due to synsedimentary tectonics as the adria microplate began to collide with europe. besides the faulted blocks, a thick sequence of predominantly shallow-marine mesozoic carbonate deposits was gently folded into broad structures, representing the precursors for the formation of deeper-marine basins during the palaeogene. uplifted mesozoic carbonates were covered by the sea during the eocene (some palaeocene carbonates were deposited only at the nw and se tips of the platform), resulting in a sequence of foraminiferal limestones accumulated in carbonate ramp environments (ćosović et al., 2004, 2008). the succession of these deposits indicates gradual deepening, resulting in different foraminiferal assemblages depending on changing water depth and energy. continued the upper cretaceous–palaeogene transition in the northern biokovo area, near the village of kozica (fig. 1), has been identified and sampled. in the first beds of the transgressive palaeogene, fragments and rare sections of dasyclad algae were observed, providing the impetus for more detailed investigations and the collection of more material, in order to perform better taxonomic determination and to establish more firmly the stratigraphic position of the algal remains. the first results revealed a rich algal assemblage quite similar to that described by barattolo (1978) and barattolo & romano (2002), with the addition of some other forms described below. a large number of thin-sections yielded more data, which enabled better definition of some morphological characteristics of the previously established species, as well as the erection of new ones, which raised problems in the relationship between the genera praturlonella and falsoli ka­ nella. a comparatively rich foraminiferal association, partly contained in the algal-bearing samples and partly acquired from successive overlying beds, enabled a more reliable definition of the stratigraphic position of the kozica algal assemblage. figure 1: geographic location of the kozica locality. grey area on the map in upper right corner represents deposits of the adcp. sokač et al.: taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia) geologia croatica 163 tectonic deformation caused basin deepening, and while carbonate facies gradually retreated towards shallower areas, in deeper parts they were gradually replaced by the so-called transitional beds – “globigerina” marls with crabs and glauconite, and so-called flysch deposits – an alternation of carbonate sandstones and variable amounts of siliciclastic material (transported into the basin from surrounding shallower areas) and autochthonous marly deposits. dasyclad algae described here have been discovered in the lowermost part of the eocene foraminiferal limestones de posited on karstified upper cretaceous limestones (fig. 2). 2.1. cretaceous deposits the deposits in the area of kozica represent the upper part of a more or less continuous succession of strata, which in this part of biokovo comprise a stratigraphic range from the middle jurassic to the eocene. upper cretaceous deposits underlying the foraminiferal limestones with dasyclad algae represent typical shallowmarine deposits of the adcp. these are skeletal–peloid wackestones to packstones, rarely mudstones, grainstones or floatstones/rudstones containing rich assemblages of benthic foraminifera and rudists. approximately 60 m below the k/t boundary, the last occurrence of the very common benthic foraminifera keramosphaerina tergestina stache has been discovered; stratigraphic range of this species is late santonian–early campanian. in the topmost 60 m pseudor­ hapydionina mediterranea (de castro) and murgella lata (luperto-sinni) which continued from older deposits are accompanied by other important index forms, nummo­ fallotia cretacea (schlumberger) (pl. xix, fig. 6), and calveziconus lecalvezae caus & cornella (pl. xix, figs. 7–10). on the basis of such an assemblage, the uppermost part of the cretaceous deposits is definitely campanian in age. cretaceous rocks were heavily karstified during the long emergent phase before transgression in the eocene, resulting in a morphologically very dissected relief infilled by limestones containing the studied algae. 2.2. eocene foraminiferal limestones this succession of eocene foraminiferal limestones generally corresponds to the typical succession in the karst di nari des (ćosović et al., 2004 and references therein), containing units named by the most common benthic fo rami nifera: miliolid limestones, alveolinid limestones, nummulitid limefigure 2: stratigraphic column of the kozica locality. geologia croatica 65/2geologia croatica 164 stones and discocyclinid limestones. in the lowermost part they comprise basal transgressive deposits, both in the study area and beyond. the basal transgressive unit, (discorbid and ostracod bearing limestones) is the most important part of the eocene succession for this study, because the described dasyclad algae occur there. these limestones infill the lowermost parts of the palaeorelief within the karstified cretaceous limestones, so their thickness may vary from zero to a couple of tens of metres. in the studied profile they are about 15 m thick. since these strata were deposited during an oscillating transgression, i.e. repeated small-scale transgressions and regressions of the sea, emersion breccia levels with small black pebbles are occasionally observed. in addition, infrequent deposits occur, showing open-marine influences (including rare planktonic foraminifera acarinina sp. and igo­ rina broedermanni (cushman & bermúdez) indicating a lower eocene age – vlasta premec-fućek, pers. comm.). the most common lithology is the alternation of brown micritic limestones and brown wackestones and packstones with variable amounts of benthic foraminifera (frequent small foraminifera including epistomaria sp., discorbis sp., small miliolids, unidentified rotaliids, chrysalidina sp., spirolina sp., and rare alveolinids), the studied dasyclad algae (that occur mostly in this part of the succession), bivalves and gastropods. most beds are rich in organic matter as a consequence of deposition in a low-energy, restricted environment, and in places charophytes are seen. the basal limestones are conformably overlain by limestones commonly composed of a vertical succession of several units, which are relatively easily recognized according to their fossil content. the oldest unit, the miliolid limestones, overlie the basal eocene limestones (or directly cretaceous limestones if the basal unit is missing), and originated in very restricted shallow-marine environments. larger miliolids (spirolina sp., periloculina dalmatina drobne; pl. xix, figs. 3–4) outnumber agglutinated conical taxa (chrysalidina sp., cribrobulimina sp.), alveolinids (alveo­ lina decastroi scotto di carlo, a. cremae checchia–rispoli, a. pinguis hottinger, glomalveolina (alveolina) minutula reichel, etc.; pl. xix, figs. 1–2, 4–5), and smaller benthic foraminifera including medocia blayensis parvati and unidentified rotaliids. the sediments were deposited in inner platform settings during the late ypresian (cuisian; drobne, 1977, 1985; drobne et al., 2011), corresponding to the shallow benthic zone (after serra-kiel et al., 1998) sbz 11. they are followed by alveolinid limestones deposited in shallow-marine environments with higher energy, more or less above the fair-weather wave base, and nummulitid limestones deposited in deeper parts of the carbonate ramp, where storm influence caused continuous reworking and transport, indicating differentiation in an inner ramp setting up to the early lutetian (sbz 13). such a stratigraphic age is also confirmed by an assemblage of planktonic foraminifera within the nummulitid limestone: acarinina primitiva (finlay), planorotalites pseudoscitula (glaessner), globigeri­ natheka kugleri (bolli, loeblich & tappan), catap­ sydrax unicavus bolli, loeblich & tappan, sub­ botina eocaena (gümbel), and s. yeguaensis (weinzierl & applin) (vlasta premec-fućek, pers. comm.). the deepest facies belt of the foraminiferal limestones is characterized by deposition of discocyclinid limestones, overlain by the transitional beds (“globigerina” marls with crabs and glauconite) and flysch, i.e. basinal deposits with common turbidite layers. due to the significant synsedimentary tectonics and local relief, facies belts migrated through time at different rates, and therefore in different areas litho and biofacially similar units may be of different age. 3. algal assemblage of the kozica locality in the northern foothills of mt. biokovo, along the cretaceous–palaeogene boundary, south of the main vrgorac–zagvozd road, basal transgressive palaeogene sediments are sporadically preserved in shallow depressions in the cretaceous palaeorelief. they contain, in addition to scarce planktic and benthic foraminifera, frequent, sometimes rich, remains of dasyclad algae. among numerous fragments and sections of visibly articulated dasyclad thalli of various dimensions, different degrees and types of calcification, and various state of preservation, two groups of mutually more or less similar forms can be generally distinguished, each characterized by some common characters. the first group includes the remains of small specimens of segmented, weakly calcified thalli, whorls visibly separated, with individually positioned acrophorous to phlo iophorous branches, visually reminiscent of clypeina-type morphology. within that group, two forms can be recognized and taxonomically identified as belonging to previously described species, namely clypeina bucuri barattolo & romano and clypeina lucana barattolo & romano. the second group includes visually similar forms which have in common a more or less regular widening and narrowing of the central cavity reflecting the articulated skeleton with the visibly spaced whorls bearing groups of branches, regardless of whether this is the result of their common point of origin or only an appearance due to different inclinations of individual branches of the same whorl. typically phloiophorous, branches are differentiated into a stalk and a swollen outer part. the interspaces between the steeply upward oriented branches of the same whorls are heavily calcified, giving rise to conical bodies, resulting in the entire skeleton having the appearance of a vertical row of inversely positioned cones. within the extremely abundant material of this group, three, possibly four, forms can be distinguished, based on differences in shape of the same type of branches, more pronounced values of some biometric parameters, the direction of growth of variably inclined branches, the type of calcitic structure of the skeletal remains, and of questionable euspondylity or metaspondylity. one form has been attributed, (though with some doubts on the generic affiliation), to the previously described species praturlonella salernitana barattolo, whereas the three remaining forms are assokač et al.: taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia) geologia croatica 165 cribed to the metaspondyle genus falsolikanella granier. based on their mutual morphological differences, as well as on whether calcification occurred within or outside the cell membrane, and the type of calcitic structure (granular or fibrous) in the preserved parts of the skeleton, one species within that group can be determined as the recently described clypeina teakolarae radoičić, jurkovšek & jo vanović, with the revised generic attribution. however, another can be described as a new species, falsolikanella? ma­ cropora n. sp., whereas the third can be determined at generic level only, as falsolikanella? sp., due to the insufficient number of illustrative sections. the authors are aware of the possibility, that the defining, delimitation, and/or ascribing of particular sections to the above mentioned taxa may, in some cases, appear doubtful and, from the viewpoint of acceptability, may be questioned or even repudiated. in addition to the unavoidable author’s subjectivities, other reasons may include the supposed similarity of some sections previously ascribed to the same taxon, and issues of ontogeny. it is also possible, that the original description may have contained some errors which were then unrecognised only becoming apparent when some taxa were separated and described later. therefore, it seems useful to redefine some morphological characteristics, emphasizing, in particular, their significance for the clearer separation and identification of taxa described. besides, the obvious similarity between species ascribed to different genera revisits the questions on the praturlonella/falsolikanella relationship. the following analysis of various genera and species from the algal assemblage of the northern biokovo foothills (the kozica locality) is based upon numerous sections contained in about 150 thin-sections, made either from a single sample or from several samples derived from the same or closely situated levels (fig. 2), collected during several visits to the locality. clypeina bucuri barattolo & romano 2002 (pls. i–iii) synonymy: 2002 clypeina bucuri n. sp.– barattolo & romano, p. 41–69, pl. 1, figs. 1–22, pl. v, figs. 1–8. remarks: rare remains of the species, originally described by barattolo & romano (2002), are restricted to the area of its type locality in scattered outcrops of the lower–middle eocene (vecchio et al., 2007) trentinara formation in the central and southern apennines of italy. the age of the clypeina-bearing interval within the trentinara formation is defined as ypresian (lower eocene) by barattolo & romano (2002) and vecchio et al. (2007). new karst dinaridic examples, with numerous and well preserved sections at the kozica locality, enable re-examination and increase understanding of its morphological characteristics in order to more precisely define its stratigraphic position. during re-examination of this species and its differences from contemporaneous taxa, the analysis of morphotypes as elaborated by barattolo & romano (2002), which eventually produced descriptions of two new clypeina species, i.e., c. bucuri and c. lucana, is not included here. therefore the species will be analyzed separately, partly repeating and partly, when necessary, supplementing the primary description, with their distinguishing characteristics and the limits of tolerable variations. description: in agreement with the original description (barattolo & romano, 2002) of the heterogeneous algal assemblage, sections of fragmented, articulated, generally small and weakly calcified algal thalli were ascribed to this species. a relatively regular cylindrical skeleton appears articulated (segmented), as a result of abrupt circular constrictions, situated at regular intervals along the thallus of individual specimens (pl. i, figs. 1, 8). thus the entire skeleton appears as a row of vertically stacked cylinders, in some cases slightly claviform, mutually separated by constrictions and sometimes visibly connected by short necks (pl. i, fig. 8). the length of individual segments appears to be constant in the same specimens (probably, because of the small number of preserved sections), but differs in different individuals. in tables 1–3 of barattolo & romano (2002), the lengths of individual segments in specimens from different samples vary as follows: table 1: 0.35–0.55; table 2: 0.28–1.00; table 3: 0.20–0.80, giving, summarily, approximate ratios of 1:2 to 1:4. measurements of the present specimens range from 0.58–1.80, in an approximate 1:3 ratio. the central cavity is enclosed, all along the thallus len gth, by a very thin calcareous envelope with smooth inner and outer surfaces. the thickness of the calcareous envelope varies from 0.025–0.12 mm, most frequently 0.04–0.08 mm, being always constant in the same specimen. exceptionally, in a small number of longitudinal sections, tapering may be noticed (pl. i, fig. 2). this is relatively more frequent in the lower part of a segment, in the zone of constrictions and connections between the upper and lower cylindrical segments (pl. i, figs. 3, 7–10), connected to the strengthened (thickened) upper part of the lower article (pl. i, fig. 8). this is probably the reason why the skeleton frequently breaks apart into separate cylindrical segments. the regular appearance of cylindrical tubes is sometimes disturbed by slight swellings of the central cavity in some segments, manifested on the outside by a slight bulge of the outer surface, perhaps only on one side of the calcareous envelope (pl. i, fig. 2). examples of well preserved specimens enable some supplements to the original description (barattolo & romano, 2002) to be made. this refers primarily to the position of the whorls, shape and calcification of the branches. the existence of only primary branches is corroborated by this material. they are situated in one-rowed whorls, mostly (but not exclusively) in the upper part of the lower segment where it becomes narrower and connects to its upper neighbour. in this zone, up to three closely spaced whorls are developed (pl. i, figs. 1, 7). characteristically, in longer segments, a separate whorl can also be developed in their central part, between the upper and lower constrictions (pl. i, figs. 2, 4–5). some transverse sections, where the central cavity is regularly circular in shape, show unevenly distributed geologia croatica 65/2geologia croatica 166 plate i 1–10 clypeina bucuri barattolo & romano, x54. 1 longitudinal–oblique section of three connected segments, slide sb–17e1/1. 2 longitudinal section of a segment with branches visible in different parts, slide sb–17e1/2. 3 longitudinal section of a segment with branches in the upper constriction, slide rak–40a/7. 4 longitudinal–oblique section of two segments with distinctly different positions of the branches, section rak–40a/34. 5 longitudinal section of a segment with branches visible in the level of upper constriction and in its middle part, slide rak–40a/36. 6 oblique section of a segment with branches visible in two levels, slide rak–40b/3. 7 longitudinal–oblique section of two connected segments; visible position of the branches in two or three close whorls, slide rak–40a/5. 8 longitudinal section of two connected segments with branches in the levels of upper constrictions, slide rak–40a/10. 9–10 longitudinal sections of isolated segments, fig. 9, slide rak–40b; fig. 10, slide rak–40a/3. branches in the same level, indicating their asymmetric arrangement in the whorl (pl. ii, fig. 8 part; pl. iii, figs. 11–12). these features had not been reported in the first description of this species (barattolo & romano 2002, fig. 8). also, such irregular distribution of the whorls in some segments makes the correlation of the biometric parameter h insignificant. thin, weakly calcified walls surrounding the cylindrical articles continue outwards along the soft tissue of the branches, thus forming a thin calcareous envelope along the entire branch length. in some specimens, stronger calcification may be observed only at the base of the branches, surrounding the outgoing small channel where the article’s envelope extends along the branch (pl. i, figs. 1, 4 part, 7; pl. ii, figs 1–2 part, 6, 10). as the branch envelope tapers toward the end of the branch, immediately above the stren gthened part, this is the critical place where the branches break off and therefore complete, or mostly preserved branches are extremely rare (pl. i, fig.4; pl. ii, fig. 10; pl. iii, figs. 1–2, 4). the breaking of branches, generally leaving only the proximal part visible, together with the tapering of the branch envelope toward the distal end, led to the illusion of apparently non-calcified distal parts of the branches (barattolo & romano, 2002). however, several sections with longer branches preserved (pl. i, figs. 4–5; pl. ii, figs. 3, 10; pl. iii, figs. 1, 7) enable a better understanding of their shape and inclination with regard to the horizontal plane. after leaving the connection to the central cavity through small outlet channels, the branches visibly and abruptly swell at the base (pl. iii, figs. 11–12) and retain the same diameter up to the distal end (pl. ii, figs. 3–10). thus the branches can be classified as belonging to the acrophorous type, as already stated by barattolo & romano (2002). the scarcity of the whorls, their different inclination, and various planar cross sections mean that it is impossible to ascertain whether even the longest branches (as illustrated) represent their true maximum length. the branch inclination of 55–70º with regard to the central axis, as mentioned in the original description (barattolo & romano, 2002), agrees with our observations concerning the part of the branches on the highest whorl in the zone where the cylindrical segment narrows. our sections, however, show greater variation of the angle between the growth direction of branches and the horizontal plane of section, depending on the distance between the consecutive whorls and their position on the segment. the branches in the whorls situated in the lower and central parts of individual segments can be horizontal, sub-horizontal, and even sli ghtly downturned (pl. i, figs. 4–6; pl. ii, fig. 10; pl. iii, figs. 2, 11). as the present material shows some previously unknown features, it is necessary to present an emended diagnosis of clypeina bucuri barattolo & romano: thallus composed of connected weakly calcified cylindrical segments, as a result of circular constrictions and expansion of the central cavity at regular intervals along every individual specimen. branches of the acrophorous type, individually calcified along their entire length and situated in up to three closely spaced whorls in the level of upper constriction of each segment. asymmetric arrangement of branches in the whorl is also possible. in longer segments, separate whorls can also be developed between the upper and lower constrictions. inclination of the branches depends on the position of the whorl. branches of the upper whorls are usually more inclined relative to the lower ones that can be sub-horizontal or even slightly down turned. clypeina lucana barattolo & romano 2002 (pls. iv–v) synonymy: 1979. praturlonella salernitana barattolo.– chiocchini et al., pl. 2, figs. 2, 9?, 11–12. 1994. praturlonella salernitana barattolo.– chiocchini et al., pl. xxxvii, figs. 9–11. ?pars 1995. praturlonella salernitana barattolo.– radoičić, pl. iii, figs. 1–9. 2002. clypeina lucana n. sp. – barattolo & romano, p. 41–69, pl. ii, figs. 9–12, pls. iii–vi, pl. vii, fig. 1 part; pl. iv, figs. 1–2. remarks: diagnosis is almost identical to that of cly­ peina bucuri barattolo & romano. clypeina lucana barattolo & romano was mainly established on the statistical analysis of biometric parameters, uniting morphotypes m2 and m3, although in reconstructions of both species (barattolo & romano, 2002, figs. 8, 19), morphological differences including the shape of articles and straight or bent laterals are clearly visible. however, comparison of the given statistical parameters for the sections of c. bucuri contained in several samples (barattolo & romano, 2002, tables 1–3), does not reveal mutually significant differences; also, the differences are neither visible sokač et al.: taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia) geologia croatica 167 geologia croatica 65/2geologia croatica 168 plate ii 1–3, 4b, 5–7; 8b , 9–10 clypeina bucuri barattolo & romano; 4a, 8a praturlonella salernitana barattolo 1 transverse, slightly oblique sections, slide rak–40a/8, x54 2 a) transverse section, b) longitudinal section of a segment, slide sb–17e1/3, x54 3 oblique section, slide rak–40a/8, x54 4 a) praturlonella salernitana barattolo – fragment of an oblique section; b) clypeina bucuri barattolo & romano – transverse section, slide sb–17–1, x22 5 different sections, slide sb–17b1/1, x54 6 oblique section of a segment, slide sb–17e1/1, x54 7 transverse, slightly oblique sections, slide rak–40a/5, x54 8 a) praturlonella salernitana – fragment of an oblique section; b) clypeina bucuri – transverse sections, slide sb–17b/1, x22 9 oblique section, slide sb–17b/1, x54 10 transverse section, slide rak–40b/2, x54. in comparison with the values of the same parameters in c. lucana (barattolo & romano, 2002, table 4). furthermore, either the values of individual parameters in one species are within the range of values of the same parameters for another species (see the tables mentioned above), or the numerical value of one parameter does not agree with the given interpretation and the visual impression gained by the photomicrographs (e.g., parameters with approximately the same or even greater values in c. bucuri than in c. lucana; although c. lucana is more heavily calcified, which is also supported by the visual impression in sections of the same magnification; see pl. ii, figs. 9–12 and pls. iii–iv in barattolo & romano, 2002). evidently, the heterogeneous material the authors had at their disposal, supported by the similarity between various sections, did not allow clear expression of the descriptive differences or establishment of distinguishing features for the two species, c. bucuri and c. lucana. the same difficulty has been a problem here creating the frequent dilemma as to which species a particular section should be ascribed, which led to the further, and probably more important question of whether determination of two species was justified in the first place. as the sections illustrated in plates iv–v also belong to an association of heterogeneous fragments, but are derived from the same sample, or adjacent samples from the same bed of the basal transgressive eocene deposits, the mutual replacement or mix-up of these species is irrelevant for the identification of stratigraphic position. nevertheless, their taxonomic validation based solely on the statistical analysis of selected biometric parameters remains questionable. therefore we directed our attention to the sections of morphologically clypeina-like forms which at least partly diverge from those presented with the description of c. lucana. within the variability range, expressed by the fluctuation of dimensions of individual specimens, the shape of the thallus, shape of the branches and their inclination, only a few sections have been ascribed to c. lucana which at least partly enabled the completion and re-definition of the original description of c. lu­ cana to be clearer. description: the variably calcified skeleton, composed of gray, sparry calcite (pl. iv, figs. 3–4, 6–9; pl. v, figs. 1–2, 4, 8), shows a generally cylindrical shape to the original thallus, with signs of apparent articulation. this articulation is the result of periodic swelling and constrictions of the central cavity, which is constant (spaced at regular intervals) in individual specimens. the calcareous envelope is comparatively thin, of constant thickness in individual specimens, but varies in thickness from specimen to specimen. it envelops the central cavity rather uniformly, closely following the swellings and constrictions and becoming thicker at the level of whorls, where it extends outward, along the branches (pl. iv, figs. 1, 4; pl. v, fig. 1). thus the thallus consists of a succession of consecutive segments, which may be longer or shorter, more barrel-shaped (pl. iv, fig. 1), or more cylindrical (pl. v, fig. 1), mutually joined by constrictions. in some specimens, the calcareous envelope appears to slightly thin out towards the lower end of the upper segment, without breaking the connection with the lower segment. a single-row of whorls are situated, as a rule, in the top part of the segment, immediately below the constrictions, bear only primary branches, which widen slightly, more or less visibly, going from the proximal to the distal end. depending on how strongly the branches widen from the base to the outer end, their shape varies from nearly acrophorous (pl. iv, fig. 1) to more pronouncedly phloiophorous (pl. v, figs. 1–10). due to a larger number of branches in a whorl and their swelling, the envelopes of the neighbouring branches are in mutual contact, thus forming a deeper or shallower bowl, depending on how steeply the branches are inclined (pl. iv, figs. 1–4; pl. v, fig. 1). the outer rim of such a bowl is slightly undulating, as a result of individually closed tops of branches (pl. v, fig. 10). inclination, i.e. the angle between the growth direction of branches and the horizontal plane, is the same for branches of the same whorl and is also more or less consistent for the branches of other whorls on one specimen; in separate individuals it can be slightly different. very rarely, a slightly variable inclination can be noticed in neighbouring branches within the same whorl (pl. iv, fig. 1, the fifth segment from the bottom), which make such sections visually similar to praturlonella salernitana barattolo. differential characteristics of clypeina bucuri barattolo & romano and clypeina lucana barattolo & romano analysis of the primary descriptions of these species (barattolo & romano, 2002), questioned whether their differentiation was firstly possible and secondly purposeful. sokač et al.: taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia) geologia croatica 169 geologia croatica 65/2geologia croatica 170 this was based on the diagnoses of these two species in the original description, as well as the minor differences in their biometric parameters, together with the partial correspondence or overlapping within the variation ranges of some parameters. however, in spite of the similarity of their generally small dimensions, segmented (articulated) and weakly calcified thallus, and whorls with acrophorous to phloiophorous branches, some new characteristics, mentioned above, enable their specific determination and individual evaluation to be based on the following differential characteristics: dimensions in mm: clypeina bucuri clypeina gr. lucana length of individual segments l art 0.50–1.50 (11) 0.35–0.77 (8) outer diameter at the level of whorls d 0.58–0.59 (18) 0.76–1.70 (16) inner diameter at the level of whorls d 0.20–0.50 (21) 0.15–0.68 (16) relation inner/outer diameter at the level of whorls d/d 23–57% (16) 15–41% (15) outer diameter of thallus between the whorls d’ 0.24–0.58 (12) 0.35–0.73 (6) inner diameter of thallus between the whorls d’ 0.15–0.39 (12) 0.24–0.48 (6) relation inner/outer diameter between the whorls d’/d’ 47–76% (12) 45–83% (6) distance between whorls h – 0.40–0.68 (6) length of branches l 0.19–0.48 (18) 0.28–0.82 (10) diameter of branches p 0.04–0.5 (18) 0.10–0.24 (12) thickness of calcareous envelope of thallus s 0.025–0.12 (27) 0.05–0.10 (8) number of branches in whorl w 7–12 14–16 inclination of branches a 0–50° 30–60° n = number of measurements (in parentheses) plate iii 1–14 clypeina bucuri barattolo & romano, x54. 1 oblique section, slide sb–17–2. 2 transverse section, slide rak–40a/9. 3 oblique section, slide sb–17b/1. 4 oblique section, slide rak–40a/7. 5 oblique section of a segment, slide rak–40a/8. 6 transverse, slightly oblique section, slide sb–17–2/1. 7 transverse section, slide rak–40a/7. 8 longitudinal section of a segment, slide rak–40a/2. 9 oblique section, slide rak–40b/2. 10 oblique section, slide rak–40a/10. 11–14 transverse sections, fig. 11, slide rak–40a/35; fig. 12, slide rak–40a/8; fig. 13, slide rak–40a/5; fig. 14, slide rak–40b/2. thus in c. bucuri we see a greater length of segments and more variability in the comparison of different individuals. segments sometimes show a slightly claviform shape, which has not been observed in c. lucana. in addition, c. bucuri is characterized by uniformly shaped branches of a more acrophorous type, whereas in c. lucana the shape of branches varies from nearly acrophorous to a more commonly expressed phloiophorous type, which depends on the intensity of their gradual swelling from the proximal to the distal end. the essential difference between the two species relates to the number of whorls and their mutual relationship within the same segment. c. bucuri has, in the upper constricted part of the lower whorl, two to three closely spaced whorls with fewer (than c. lucana) fully individualized branches, clearly separated from one another. the branches in each of the closely spaced whorls have different inclinations, the branches of the highest whorl being more steeply inclined than the branches in the lower whorls. in contrast, c. lucana has, in the top part of the constrictions, only one whorl with more branches (than in c. bucuri) of uniform inclination. because of their larger number and gradual widening going from the proximal to the distal end, the branches in c. lucana are in mutual contact and thus form a more or less shallow or deep bowl, depending on the inclination of branches (this feature also occurs frequently in other clypeina species). calcareous enveloping (closing) of the distal ends of individual branches gives an undulating rim of the bowl. in contrast to c. lucana, (with one whorl of branches in the upper constricted part of the lower segment), c. bucuri has, as previously mentioned in that position, two to three whorls which sometimes are developed, in longer segments, also in parts of the segments between the lower and upper constrictions. in conclusion, c. bucuri is more weakly calcified and comprises forms with more uniform characters, whereas c. lu­ cana, based both on illustrations in the original descriptions (barattolo & romano, 2002, pls. iii–vii) and present sections ascribed to that species (pls. iv–v), includes more heterogeneous material, with pronounced variability in comparison to different sections which unite, under the same denominator, some common but variable characteristics. therefore it seems preferable not to use species-specific determination of that species, but to include such variable sections within the frames of the clypeina lucana group. sokač et al.: taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia) geologia croatica 171 geologia croatica 65/2geologia croatica 172 plate iv 1, 2b, 3–4, 5b, 6–10 clypeina gr. lucana barattolo & romano; 2a, 5a praturlonella salernitana barattolo; 2c clypeina bucuri barattolo & romano. 1 longitudinal section, slide sb–17e1/1, x22. 2 a) praturlonella salernitana – fragment; b) clypeina gr. lucana – oblique section; c) clypeina bucuri – oblique section, slide sb–17b/1, x22. 3 transverse, slightly oblique section, slide rak–40a/33, x34. 4 longitudinal section, slide sb–17–1, x34. 5 a) praturlonella salernitana – longitudinal section; b) clypeina gr. lucana – transverse–oblique section, slide sb–17b/1, x22. 6 transverse section, slide koz–8, x54. 7 longitudinal section – reflected light, sample sb–17e2, x 18. 8 longitudinal section, slide b–17c3/3, x22. 9 transverse section, slide sb–17c/3, x34. 10 transverse, slightly oblique section, slide sb–17e1/2, x34. relationship between the genera praturlonella barattolo 1978 and falsolikanella granier 1986 before proceeding to the description of mutually similar species included in the second group within the algal assemblage at the kozica locality ascribed to the genera pratur­ lonella and falsolikanella, it seems necessary to re-evaluate some dilemmas regarding the authors’ criteria and their interpretations in the original descriptions, in order to clarify the relationship between these genera, and assess the possibly doubtful taxonomic validity of falsolikanella. the genus praturlonella was established by barattolo (1978), based on the morphological characteristics and author’s interpretation of the species praturlonella saler­ nitana. the species’ euspondility was interpreted as having single-rowed, well-spaced whorls, bearing undivided, individually situated, phloiophorous branches, variously inclined within the same whorl. the description of genus and species is illustrated by numerous sections (barattolo, 1978, pls. i–xix) of heterogeneous material regarding the dimensions of the thallus, different shape of branches, existing or non-existing differences in the inclination of neighbouring branches in the same whorl, being interpreted as different growth stages of the thallus. all this results in a broad range of visual diversity and some sections originally ascribed to p. salernitana may appear doubtful, possibly belonging to the subsequently described clypeina lucana barattolo & romano (2002), i.e., the sections in barattolo (1978, pl. iii, figs. 1–3, 5; pl. v, fig. 4; pl. ix, fig. 8). discussion of the relationship between the genus praturlonella and the later established falsolikanella granier, 1986, suggests that when ascribing individual species to either of the two, the main question refers to the primary starting point of branches, i.e., whether they are euspondyle or metaspondyle. granier (1986, 1987) established the metaspondyle genus falsolikanella, diagnostically defined by vestibules in the proximal part of the branches, having the function of a primary branch which bears the tuft of fertile secondaries. granier & berthou (1994) established the genus milanovicella and table 1 illustrated differences between similar genera draconisella, falsolikanella, likanella, mi­ lanovicella, praturlonella and selliporella. euspondyl genera are differentiated on the basis of one-row (praturlonella), two-row (milanovicella) or three-row (draconisella) whorls of phloiophorous branches, or three-row whorls of trichophorous (fusiformes) branches (likanella). metaspondyl genera with one-row whorls are differentiated on the basis of growth of the tuft of the trichophorous branches from the short branch (= vestibule) of the first order (selliporella) or the tuft of the phloiophorous (piriform) branches from the vestibule (falsolikanella). repeated analysis of the distinguishing characteristics of these genera and their mutual relationships (e.g. sokač, 1996), resulted in the transference of particular species from one genus to the other. schlagintweit (1990) transferred likanella hammudai radoičić to falsolikanella, in order for it to be later transferred by ensslin & schla gintweit (1999) to the milanovicella. kuss & conrad (1991) assigned the same species to the genus pratur­ lonella, but kuss (1994) denied this combination and ac cepted the primary determination of likanella hammudai as the only correct one. thus, on establishment of praturlonella, the previously described likanella danilovae radoičić (1969) was included into that genus, only to be later (granier et al., 1999) transferred once more to falsolikanella. similarly, haly­ corine nerae, originally described by dragastan et al. (1978), was transferred by bucur (1993) first into pra tur­ lonella, and later into falsolikanella (bucur et al., 2000). all these examples clearly show that the generic determination at some time was influenced by the various approaches of different authors, based mostly on personal appraisal. reasons for this may include the difficulty of obtaining adequate sections, cutting through the starting point of the base of a branch, as a result of the shape of the thallus, the large distance between the whorls situated at the constricted parts of the thallus, the smaller number of branches and their large mutual distance within the same whorl (in metaspondyle types), very short and slightly developed primary branches, or vestibule (in metaspondyle types), and possible destruction of the inner wall, which considerably obstructs the insight into the point of origin of the branches. some sections illustrated by barattolo (1978, pl. vii, fig. 4, upper right; pl. x, fig. 2 left side, fig. 5, lower whorl, fig. 6 left side; pl. xi, figs. 1, 6; pl. xii, fig. 2, right side, upper and middle whorl; pl. xiii, fig. 4, upper whorl, left side) indicate a supposed questionable metaspondylity. the same feature is suggested by the frequent occurrences of shallow sags on the inner wall of the central cavity at the level of the origin sokač et al.: taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia) geologia croatica 173 geologia croatica 65/2geologia croatica 174 plate v 1–10 clypeina gr. lucana barattolo & romano. 1 longitudinal section, slide rak–40a/34, x42. 2–3 transverse, slightly oblique section, fig. 2, slide sb–17b, x52; fig. 3, slide koz–6, x22. 4 oblique section, slide koz–5, x54. 5 transverse section, slide rak–40a/23, x52. 6 transverse, slightly oblique section, slide sb–17c2, x52. 7. transverse section, slide koz–19, x22. 8 transverse–oblique section, slide rok–40a/1, x52. 9 tangential–oblique section, slide sb–17e2/18, x22. 10 transverse–oblique section, slide sb–17c3/3, x34. 11 neomeris sp. – oblique section, slide koz–15, x22. of the branches. however, despite comments above and some doubts regarding the possible metaspondylity of that genus, for the time being we have no clear and unquestionable indications as the basis for a supplemented or new (emended) interpretation of the present diagnosis of praturlonella, which remains valid regardless of possible priority changes. however, possible metaspondylity of the genus praturlo­ nella would question the continued existence of falsoli­ kanella. these questions should be answered by further investigation and analysis of new sections of the type material of p. salernitana. they are only some of the dilemmas which arose during the elaboration of this second group of the kozica algal assemblage and which may contribute to the understanding that close and similar forms, visually almost identical in some morphological characters, may be attributed to different genera, and even to different tribes. the impression is that an earlier error which cannot be corrected with valid arguments but which leads into an illogical and probably unjustified taxonomic classification is being compounded. praturlonella salernitana barattolo 1978 (pls. vi–viii) taking in account the aforementioned dilemmas, and in agreement with the original description, we have ascribed the sections illustrated in plates vi–viii to praturlonella salernitana barattolo. this species is characterized by a cylindrical thallus with successively alternating, in regular intervals, short constrictions and longer widened parts of the central cavity resulting in the articulated appearance of the thallus, described by barattolo (1978) as a necklace of pearls. the calcified thallus is composed of light gray, mosaic calcite. the intensity of calcification is remarkable, but variable from specimen to specimen, depending on the length of a segment (distance between the whorls) and the inclination of branches in a whorl. in shorter segments (articles) with less steeply inclined branches, the width increases and the height of the conical part, formed by calcitic fillings in the interspaces between the branches of the same whorl decreases, resulting in a more massive calcitic skeleton (pl. vii, figs. 3, 8). in longer segments and more steeply inclined branches, the width of conical parts is smaller but their mutual distance is larger and the thickness of the calcareous wall gradually decreases downwards, giving the general impression of weaker calcification (pl. vi, fig. 1; pl. vii, figs. 2, 4). according to the original description (barattolo, 1978), the species is euspondyle. the branches are arranged in one-row, quite widely spaced whorls, situated in the top part of the lower segment, at the transition from the widened to the constricted part, immediately below the maximum constriction. clearly individual, phloiophorous branches within a whorl are variously inclined toward the surface of the thallus, giving an impression (in longitudinal and oblique sections) of being grouped into bundles, resulting, in transverse sections, in 2–3 circular rows of pores. the number of branches in a whorl and their more or less steep inclination varies, depending on the growth stage of the thallus (barattolo, 1978). a smaller number of branches and their lesser inclination in younger growth stages increases in the adult stages. each phloiophorous branch differentiates into a relatively long stalk and a shorter, widened distal part, which is, in barattolo’s (1978, figs. 9–13) reconstruction, represented as a shallow bowl. in our sections (pl. vii, fig. 1; pl. viii, fig. 1), the distal widening is more like a shorter or longer cylindrical swelling with rounded edges. the point of origin of the branches and their mutual relationship in the proximal part are not completely clear. in our opinion, euspondyle interpretation remains questionable. this doubt might be supported by the fact that the genus praturlonella has only two species, in contrast to the numerous, morphologically very similar species ascribed to the metaspondyle genus falsolikanella, the number of which is steadily increasing. falsolikanella? teakolarae (radoičić, jurkovšek & jovanović, 2011) n. comb. (pls. ix–xi; pl. xviii, figs. 1–4) synonymy: 2011. clypeina teakolarae sp. nov. – ra doi čić, jurkov šek & jovanović, p. 13–30, text-figs. 4–6, pls. i–vi. sections of this species also occur in the kozica algal assemblage. their analysis, based on sections figured in plates ix–xi, revealed some newly registered morphological features of the thallus, type of branches and their shape sokač et al.: taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia) geologia croatica 175 geologia croatica 65/2geologia croatica 176 and arrangement, which makes a generic revision necessary, i.e., its tentative attribution to falsolikanella granier, as well as an addition to the original description. dimensions in mm maximum observed length of thallus l 5.4 length of individual segments lart 0.9 (2) outer diameter at the lowest part of whorls d 1.35–2.52 (9) inner diameter at the level of whorls d 0.44–1.20 (9) relation inner/outer diameter d/d 0.263–0.476 (9) outer thallus diameter between the whorls d’ 0.62–1.10 (7) inner thallus diameter between the whorls d’ 0.52–1.00 (4) relation inner/outer diameter between the whorls d’/d’ 0.804–0.966 (4) distance between whorls h 0.76–1.44 (3) length of branches l 0.48–0.96 (3) length of branch’s stalk-axial cavity lpr 0.72–0.83 (5) length of the branch’s distal part ldi ?0.26 (1) average diameter of branch in calcified part p 0.24–0.34 (5) thickness of branch’s hyaline envelope ss 0.05–0.10 (9) diameter of branch’s distal part pdi up to 0.37 (4) thickness of thallus wall between the whorls s 0.04–0.06 (3) number of branches per whorl (assumed) w ?5–8 number branches in a bundle (assumed) w’ ?4–6 total number of branches in a whorl w’’ ?ca. 50 inclination of branches a 20°–70° n = number of measurements (in parentheses) description: thallus has a generally cylindrical shape, characterized by the relatively regular alternation of short intervals of slight narrowing and longer intervals of widening (swelling) of the central cavity, resulting in an indistinctly segmented shape (pl. ix, fig. 1; pl. x, figs. 2–3). each segment bears, in its upper part, whorls of assumed metaspondyle branches (pl. ix, figs 1–2; pl. xi, figs. 7–9). the tufts of branches belong to distinctly separated whorls, the mutual distance of which depends on the length of individual segments, as seen in tangential or more or less oblique sections. they appear as wreaths of double, triple, or irregularly distributed envelopes of individual branches in the neighbouring tufts of the same whorl. at the same time, this rules out the possible existence of doubled independent whorls (twin-whorls; radoičić et al., 2011), which has never been reported in clypeina, and is not compatible with the generic diagnosis (bassoullet et al., 1978). the appearance of the whorls is the result of a characteristic calcification pattern, restricted to the branches, which conrad & varol (1990) described as the “intracellular calcification developed in vivo”. the vitreous branch’s envelopes are characterized by a yellowish colour and distinctly developed radial calcitic structure (pl. ix, figs. 4–7; pl. x, figs. 4–5, 7; pl. xviii, figs. 1, 4), which often may be destroyed by subsequent recrystallization. neighbouring whorls of metaspondyle branches are connected into a coherent thallus by a very thin inter-whorl membrane, which is very weakly calcified so that it is most frequently erased or only preserved as fragments, thus being barely visible as an interrupted outline (pl. ix, figs. 1–2; pl. x, figs. 2–3). in some sections, the membrane becomes more strongly pigmented with iron oxides during fossilization and thus becomes more easily visible due to its brownish-reddish colour (pl. xviii, figs. 2–3) which is often dispersed as blotches into the surrounding sediment. individual branches within a tuft are distinctly phloiophorous. their common point of origin is vaguely marked by insufficient calcification or only weak mineralization, so it is only assumed to be shaped as a slight bulge of the central cavity (vestibule). this is indicated by the longitudinal sections of individual whorls (pl. ix, fig. 2; pl. xi, figs. 7–8, marked by arrow) or proximal tangential (cortical) sections (pl. xi, fig. 10) with distinctly grouped pores, outlined by a thin margin. the possibility of a non-calcified or only weakly mineralized point of origin of the branches is also indicated by very thin envelope in their proximal part (pl. xi, fig. 4, marked by arrow). the vitreous, fibrous calcitic envelope of each individual branch thickens toward its central part, reaching a maximum thickness (pl. xi, figs. 5–6, marked by arrow) and gradually tapering distally, so that the top parts of the branches, open to the exterior, are not, or are only rarely and fragmentarily, preserved. the increasing thickness of the calcification within the branch’s membrane pushes back the soft tissue, shaping it into a massive spindle-shaped stem, and, further outward, lacking the calcification, into a broad, open calyx (pl. xi, fig. 6), looking, as a whole, like a chalice. the oval-shaped space inside the branch probably functioned as gametangium, i.e. the species is cladosporous. the fact that the outer parts of the branches remain uncalcified during life is indicated by the post-mortem input of particles of the surrounding sediment into the remaining branch’s cavity, with visible grain-size differentiation, i.e., with particles of decreasing diameter going from proximal to the distal end, the latter being most frequently infilled by muddy sediment (pl. xi, fig. 4). the number of branches within a tuft cannot be defined with certainty, but is estimated to be 4–6. the variability of their number is suggested by tangential sections of individual whorls, in which the ring-like sections of vitreous branch’s envelopes of neighbouring branches appear in alternating positions in two (pl. ix, fig. 7; pl. x, figs. 4, 7) or three (pl. ix, figs. 6, 8; pl. xi, fig. 4) rows, sometimes seemingly in irregular arrangement. depending on the number of branches within a tuft and their individual robustness, the neighbouring branches may be well spaced, i.e., mutually separated (pl. x, fig. 5), or, more often, more or less tightly pressed one to another and slightly irregularly compressed (pl. ix, figs. 7–8). because of this, their generally ovoid forms appear in transverse sections of sokač et al.: taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia) geologia croatica 177 branches as more or less regular ring-shaped (pl. x, figs. 4–5 part) or, more rarely, as indistinctly angular (pl. ix, figs. 5, 7 part), envelopes. the direction of growth of branches is generally upwards, their inclination varying from sub-horizontal up to more or less steeply inclined, depending on the degree of divergence between the branches of the same tuft. similarities and differences: in spite of the general similarity between all falsolikanella species, concerning their thallus morphology, resulting from the distribution of widely spaced whorls with metaspondyle branches, characteristic calcification pattern depending on the direction of growth and number of branches in the form of a row of beads (f. danilovae; falsolikanella? sp. – pl. xviii, figs. 8–9), lower or higher, more or less regular rings (f. campanensis, f. nerae), and inversely assembled conical bodies (f.? tea­ kolarae, f.? macropora n. sp.), all species have some species-specific characters which make their distinction possible. these concern their dimensions, shape of branches (though all generally being of the phloiophorous type), intensity and pattern of calcification (intracellular or extracellular), and structure of calcite (grainy or radial). falsolikanella? macropora n. sp. (pls. xii–xvii; pl. xviii, figs. 5–7) origin of name: the species is characterized by characteristically large pores, visible in variously oriented sections cutting through the outer parts of the branches. type locality: northern foothills of mt. biokovo, near the village of kozica, 100 m south of the main zagvozd– vrgo rac road. geographical coordinates: l = 43°15’31.3’ n; j = 17°13’21.2’ e (fig. 1). type stratum: grey-brownish bioclastic wackestone/ packstone containing dasyclad and mollusc bioclasts. matrix is micritic with rare peloids, containing scattered debris of planktonic foraminifera, and in the lower part of the bed, rare black-pebbles. these deposits were accumulated in the shallow-marine environment characterized by oscillating transgression over the cretaceous palaeorelief, therefore comprising a remarkable mixture of elements indicating short-lasting emergence and open-sea influences. according to both large benthic foraminifera and planktonic foraminifera, the studied deposits are ypresian in age (lower eocene). holotype: oblique section, contained in thin-section from sample rak–40a, labelled rak–40a/11, figured in pl. xiii, fig. 5. isotypes are represented by numerous, variously oriented sections, figured in pls. xii–xvii. original material is deposited in the branko sokač collection of holotypes and isotypes with the croatian geological survey, zagreb. diagnosis: thallus with well calcified whorls, characterized by more or less distinctly pronounced, successive regular widenings (swellings) and narrowings (constrictions) of the central cavity, giving the appearance of a row of connected, cylindrical or barrel-shaped, segments. the species is metaspondyle, of the cladosporous type. whorls of assumed metaspondyle branches are situated in the top, constricted parts of individual segments. the common point of origin of a branch tuft is marked by a shallow depression on the inner wall (vestibule) or an extremely short branch. each tuft contains several phloiophorous branches, clearly differentiated into a stem and an outer, clearly swollen (inflated) outer part. dimensions in mm: maximum observed length of thallus l 8.7 length of individual segments lart 0.86–1.67(11) outer diameter at the lowest part of whorls d 1.70–4.80(32) inner diameter at the level of whorls d 0.36–1.30(30) relation between and outer diameter at the whorl level d/d 0.230–0.384(27) outer thallus diameter between the whorls d’ 0.58–2.18(11) inner thallus diameter between the whorls d’ 0.38–1.45(16) relation inner/outer diameter between the whorls d’/d’ 0.655–0.912(10) distance between whorls h 0.86–1.95(14) length of branches l 0.96–1.95(21) length of branch’s stalk-proximal part lpr 0.24–0.67(25) length of the branch’s distal (swollen) part ldi 0.60–1.45(23) diameter of branch’s stalk-proximal part ppr 0.06–0.12(28) diameter of the branch’s swollen (distal) part pdi 0.20–0.48(30) thickness of thallus wall between the whorls s 0.07–0.11(14) number of branches per whorl (assumed) w ?6–8 number branches in a bundle (assumed) w’ ?5–7 total number of branches per whorl (assumed) ?about 50 inclination of branches a 0º–70º n = number of measurements (in parentheses) description: the new species is represented by the generally cylindrical shape of the skeleton, featuring a more or less pronounced regular alternation of successive constrictions and swellings of the central cavity, resulting in an apparent segmentation of mutually connected segments. individual segments between the whorls may have a cylindrical shape (pl. xiv, fig. 5; pl. xv, fig. 2) or be more barrel-shaped (pl. xv, fig. 1). variable calcification of the thallus reflects its outer morphology. the more massive calcification at the level of the whorls in a segment is the result of a more massive calcification in the proximal part of the branches, where there is more space between the stalks of the neighbouring branches in a whorl (pl. xiv, figs. 2, 5; pl. xv, figs. 1–2). outer parts of the whorls are characterized by distal swellgeologia croatica 65/2geologia croatica 178 ings of branches and are therefore weakly calcified, the calcification consisting of thin envelopes of branches being pressed close to each other (pl. xiii, figs. 1, 3, 6; pl. xv, fig. 6; pl. xvi, figs. 3, 7; pl. xvii, figs. 1–2, 4–5, 10). the parts of the thallus between the whorls are equally weakly calcified, with only a thin calcareous envelope (pl. xiv, figs. 5, 9; pl. xv, figs. 1–2), which causes the fragility of the skeleton and therefore the rare occurrence of longer skeletal fragments. the main feature distinguishing this species from the morphologically similar falsolikanella? teakolarae (radoičić et al.) is that the calcareous skeleton is composed of light gray, fineto medium-grained, sparitic mosaic calcitic infilling of the spaces between the branches (pl. xiii, fig. 1; pl. xiv, figs. 1–2). the inner surface of the central cavity is clearly and regularly delineated, in contrast to the eroded outer surface, with alternating calcified ring-like cones with bundles of branches, steeply inclined upwards and therefore most frequently covering the thin envelopes in the internodal parts of the thallus. another important characteristic of the new species is its metaspondylity, this being the key feature, along with some morphological characteristics, for its assignation, however questionable, to the genus falsolikanella (for the relationship between the genera praturlonella and falsolikanella see above). the whorls are situated in the constricted, top part of the segments. the metaspondyle point of origin of the group (tuft) of branches is rare and difficult to observe in sections, due to their position in the constricted part of the thallus, their small number per whorl, and the distance between the consecutive whorls. it is manifested by shallow recesses in the inner side of the calcareous envelope (pl. xiii, figs. 1, 8; pl. xv, fig. 1; pl. xvi, figs. 1, 10; pl. xvii, figs. 9, 11 – marked by arrows), short, indistinctly defined stalk (pl. xiv, figs. 5, 8–9 – marked by arrows), or it is indirectly indicated by connection and concentration of pores in tangential sections (pl. xiv, fig. 1; pl. xvii, fig. 12 – marked by arrow). a tuft of individual phloiophorous branches, clearly differentiated into a thin, proximal stalk and an elongated and swollen terminal part, grows out of such a common point of origin. in their initial part, the stalks of the branches can be directed into different directions, sometimes even downturned, but going outwards they become more steeply directed upwards, with a general tendency of growing upwards. after the first 1/3 of its length, the branch abruptly widens into a distinctly swollen outer part with reduced calcification, consisting only of thin envelopes of branches. due to their distal swellings, the branches become pressed closely to one another which results in their variable shape in longitudinal sections (pl. xii fig. 9; pl. xiii, figs. 1–3, 5; pl. xiv, figs. 3, 6; pl. xvi, fig. 7). this visual variability can be partly due to the different position of the plane of section, but it is confirmed by variously and irregularly shaped pores, (ranging from oval to polygonal), in distal tangential (cortical) sections (pl. xv, fig. 6; pl. xvi, fig. 3). weak calcification in the distal region and the abrasion of the outer surface makes determination of the full length of the branches and the insight into their terminations questionable. the absence of transverse sections with clearly visible points of origin of the bundles of branches, leaves open the question of their exact number in a whorl; this, as well as the number of branches per bundle, can only be approximated on the basis of how much space they occupy. the variable angle of inclination results in the variable direction of growth of individual branches within the same bundle. thus, the lowest branches in a tuft may be variously bent downwards or upwards in the proximal part (stalk), becoming horizontal (pl. xiv, figs. 4, 10) or more or less steeply inclined in the distal part. the species is cladosporous, with rarely visible recrystallized cysts, regularly arranged in the swollen part of a branch (pl. xvi, fig. 7 – marked by arrow). similarities and differences: falsolikanella? macro­ pora n. sp. is visually close to, and by some morphological characters similar to the contemporaneous praturlonella salernitana barattolo (1978). descriptively, their basic difference, praturlonella salernitana being euspondyle and falsolikanella? macropora n. sp. being metaspondyle, is possibly the result of different authors’ interpretations – and seems problematic for their clear and certain generic and species-specific determination, which explains the present dilemma in designation of the generic assignment of the new species, indicated by a question-mark). therefore, in distinguishing the two species and establishing the new species (f.? macropora), we must confine ourselves to different values of biometric parameters and some specific morphological characteristics. apart from a general similarity regarding the apparent segmentation in the outer shape of the skeleton and the position of whorls on the thallus, the values of individual biometric parameters are twice or even three times larger in f.? macropora n. sp. than in p. salernitana. despite the fact that the length of branches in p. salernitana has not been stated, visual comparison clearly shows their considerably larger length in f.? macropora, this being so in spite of the seemingly longer stalk in p. salernitana, regarding, proportionally, the total dimensions of the thallus. other visible plate vi 1–6 praturlonella salernitana barattolo, x22. 1 longitudinal–tangential section, slide koz–19. 2 longitudinal section, slide koz–13. 3 oblique section, slide koz–21. 4 longitudinal, slightly oblique section, slide koz–14. 5 longitudinal–tangential section, slide koz–27. 6 tangential–oblique section, slide koz–21. sokač et al.: taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia) geologia croatica 179 geologia croatica 65/2geologia croatica 180 plate vii 1–8 praturlonella salernitana barattolo. 1 oblique section, slide koz–16, x22. 2 longitudinal section, slide koz–7, x22. 3 longitudinal–tangential section, slide sb–17e1/2, x22. 4 longitudinal–oblique section, slide koz–13, x22. 5 longitudinal section, slide sb–17b1, x34. 6 tangential section of a whorl, slide koz–6, x22. 7 oblique–longitudinal section, slide koz–23, x22. 8 tangential–longitudinal section, slide koz–18, x22. differences include the shape of the distal swellings, which are considerably larger (being both longer and wider) in f.? macropora. the lack of sections cutting through the peripheral part of the branches (cortical sections) in the original description of praturlonella salernitana barattolo (1978, pls. i–xix), regardless of the author’s interpretation (barattolo, 1978, text-figs. 9–13), does not allow reliable insight into the similarities and differences in the outer peripheral (cortical) parts of the thallus of the two species. therefore it appears justified to emphasize that in f.? ma­ cropora the distal swellings of the branches are 2 to 3 times longer than the stalk, have an elongated cylindrical to irregularly elliptical shape, a tapering or else swollen outer termination, more or less deformed, and result in oval, trian gular, or irregularly polygonal very large pores, having dif ferent diameters in the same level of transverse sections. the fragmentary tangential sections illustrated in barattolo (1978, pl. xvi, figs. 3, 6) are somewhat confusing, as the questions of how the distal ends of the branches in p. saler­ nitana are shaped, or whether those sections possibly belong to the new species coming from the same stratigraphic level remain. falsolikanella? macropora is similar to the contemporaneous f.? teakolarae (radoičić et al.) in the shape of thallus and in some biometric parameters, but differs clearly from it by pronounced extracellular calcification, which forms the skeleton, consisting of a fineto medium-grained grey sparitic matrix with mosaic texture. falsolikanella? ma­ cropora is distinguished from f. danilovae (radoičić) and f. nerae (dragastan et al.) by its larger size, (including all measured dimensions), the morphology of the skeleton, and growth direction and shape of the branches. almost the same differences apply to falsolikanella campanensis (azema & jafrezzo), which is characterized by a smaller number of branches in a tuft, their intracellular calcification and their being open at the distal end. acknowledgement the authors would like to thank reviewers, academician ivan gušić (zagreb) and dr. felix schlagintweit (munich), for their very helpful and constructive comments which significantly improved the manuscript. we appreciate very much the species identification of planktonic foraminifera by dr. vlasta premec fućek (ina zagreb). we are thankful to dr. josipa velić (university of zagreb) for assistance in fieldwork. this study was supported by the ministry of science, education and sports of the republic of croatia through projects # 181-1811096-1093, 1811951126-1134, 195-1953068-0242, 195-1953068-2704 and 119-1191152-1167. references barattolo, f. (1978): su di una nuova dasicladacea (alghe verdi) nel paleocene dell’ appennino meridionale.– boll. soc. nat. napoli, 87, 83–157. barattolo, f. & romano, r. (2002): clypeina bucuri n. sp. and clypeina lucana n. sp. (green algae, dasycladales) from the uppermost paleocene(?)–lower eocene of trentinara formation (southern italy).– in: bucur, i.i. & filipescu, s. (eds.): research advances in calcareous algae and microbial carbonates. proceedings of the 4th ifaa regional meeting, cluj-napoca, august 29–september 5, 2001, 41–69. bassoullet, j.p., bernier, p., conrad, m.a., deloffre, r. & jaffrezo, m. (1978): les algues dasycladacées du jurassique et du crétacé.– géobios, mém. spéc., 2, 1–330, villeurbanne. bucur, i.i. (1993): some new or poorly known calcareous algae (dasycladales, gymnocodiaceae) in the lower cretaceous deposits from the resita–moldova noua zone (southern carpathians, romania).– rev. espan. micropal., 25/1, madrid, 93–126. bucur, i.i., koch, r., kirmaci, z.m. & tasli, k. (2000): les algues dasycladales du crétacé inférieur (calcaire de berdiga) de kircaova (région de kale–gümüshane, ne turquie).– rev. paléobiol., 19/2, genève, 435–463. chiocchini, m., mancinelli, a., molinari-paganelli, v. & tilia-zuccari, a. (1979): répartition stratigraphique des algues dasycladales et codiacées dans les successions mésozoïques de plate-forme carbonatée du lazio centre-méridional (italie).– bull. cent. rech. explor.– prod. elf-aquitaine, 3/2, pau, 525–535. chiocchini, m., farinacci, a., mancinelli, a., molinari, u. & potetti, m. (1994): biostratigrafia a foraminiferi, dasicladali e calpionelle delle succesioni carbonatiche mesozoiche dell’appenino centrale (italia).– in: mancinelli, a. (ed.): biostratigrafia dell’italia centrale. studi geol. camerti, vol. spec., camerino, 3–128. conrad, m.a. & varol, b. (1990): cylindroporella taurica, n.sp., urges to review different patterns of calcification in the mesozoic dasycladales (green algae).– arch. sci., 43/1, genève, 193–214. ćosović, v., drobne, k. & moro, a. (2004): paleoenvironmental model for eocene foraminiferal limestones of the adriatic carbonate platform (istrian peninsula).– facies, 50/1, 61–75. ćosović, v., marjanac, t., drobne, k. & moro, a. (2008): outer dinarides: eastern adriatic coast.– in: mccann, t. (ed.): geology of central europe. geological society london, 79–86. dragastan, o., bucur, i.i. & demeter, i. (1978): date noi privind biostratigrafia depozitelor barremian-albiene din partea central-estica a zonei resita-moldova noua (banat), obtinute prin fosokač et al.: taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia) geologia croatica 181 geologia croatica 65/2geologia croatica 182 plate viii 1–11 praturlonella salernitana barattolo, x22. 1 oblique–tangential section, slide sb–17–2/1 2, 3, 6 oblique sections, fig. 2, slide sb–17–1/2; fig. 3, slide koz–4; fig. 6, slide sb–17e1/3. 4, 7 tangential sections, fig. 4, slide koz–1; fig. 7, slide koz–29. 5, 8–11 transverse, slightly oblique sections, fig. 5, slide koz–27; fig. 8, slide koz–2; fig. 9, slide koz–24; fig. 10, slide sb–17b2/9; fig. 11, slide koz–5. rajul de referinta de la sopotul nou.dari de seama ale sedint., lxiv/5, bucuresti, 17–36. drobne, k. (1977): alvéolines paléogènes de la slovénie et de l’istrie.– schweiz. paläont. abhandl., 99, 1–132. drobne, k. (1985): periloculina dalmatina a new trematophorid miliolid foraminifera from the cuisian of yugoslavia.– razprave 4. razr. sazu, 26, 159–176. drobne, k., ćosović, v., moro, a. & bucković, d. (2011): the role of the palaeogene adriatic carbonate platform in the spatial distribution of alveolinids.– turkish j. earth sci., 20, 721–751. ensslin, r. & schlagintweit, f. (1999): contributions to the knowledge of upper cretaceous calcareous algae from the central middle atlas mountains, morocc.– z. dt. geol. ges., 149/4, stuttgart, 473–486. granier, b. (1986): algues chlorophyceae du jurassique terminal et du crétacé inférieur eu alicante.– mediterránea, ser. geol., 5, alicante, 5–96. granier, b. (1987): révision de likanella campanensis azéma & jaffrezo, 1972, algue dasycladacée du crétacé inférieur du sudest de l’espagne”.– rev. paléobiol., 6/2, genève, 207–212. granier, b. & berthou, p.y. (1994): description of milanovicella momciliana n. gen., n. sp., algue dasycladales du portlandien de l´algarve central (portugal), et validation de quelques taxons affins.– rev. micropaléont., 37/2, 113–121. granier, b., bucur, i.i. & trabold, g. (1999): falsolikanella danilovae radoičić ex barattolo 1978, n. comb., a diploporacean alga from the urgonian facies.– acta palaeont. romaniae, 2, cluj napoca, 177–181. korbar, t. (2009): orogenic evolution of the external dinarides in the ne adriatic region: a model constrained by tectonostratigraphy of upper cretaceous to paleogene carbonates.– earth sci. rev., 96/4, 296–312. kuss, j. (1994): cretaceous (albian-turonian) calcareous algae from egypt and jordan – systematics, stratigraphy and paleogeography.– abh. geol. b.-a., 50, 295–317. kuss, j. & conrad, m.a. (1991) calcareous algae from cretaceous carbonates of egypt, sinai, and southern jordan.– j. paleont., 65/5, 869–882. radoičić, r. (1969): likanella ? danilovae n. sp. and some other lower cretaceous dasycladaceae from the outer dinarides.– bull. inst. geol. geoph. res. (geology), a, 26 (1968), beograd, 237–275. radoičić, r. (1974): a new palaeocene actinoporella (dasycladaceae), a preliminary report.– bull. sci. cons. acad. yougosl. (a), 19, zagreb, 9–10. radoičić, r. (1995): on the age of limestone with actinoporella ku­ koci radoičić, 1975 and praturlonella salernitana barattolo, 1978 (dasycladacean algues).– rev. paleobiol., 14/1, 95–105. radoičić, r. (2004): note on paleocene algae in the dubrovnik coast (adriatic carbonate platform).– ann. geol. penins. balkanique, 65, beograd, 29–45. radoičić, r., jurkovšek b. & jovanović, d. (2011): cly­ peina teakolarae sp. nov., a dasycladalean alga from lower eocene of rakitovec (čićarija, slovenia).– geologija, 54/1, ljubljana, 13–30. schlagintweit, f. (1990): taxonomic revision of likanella ham­ mudai radoicic, 1975, dasycladacean alga from the upper cretaceous of the northern calcareous alps (gosau formation, coniaciuan).– rev. paléobiol., 9/2, 257–261. serra-kiel, j., hottinger, l., drobne, k., ferràndez-canadell, c., less, gy., jauhri, a.k., pignatti, j., samsó, j.m., sirel, e., tambareau, y., tosquella, j., zakrevskaya, e. (1998): larger foraminifera biostratigraphy of the tethyan paleocene and eocene.– bull. soc. géol. france, 169, 281–299. sokač, b. (1996): taxonomic review of some barremian and aptian calcareous algae (dasycladales) from the dinaric and adriatic karst regions of croatia.– geol. croat, 49/1, 1–79. vecchio, e., barattolo, f. & hottinger, l. (2007): alveolina horizons in the trentinara formation (southern apennines, italy): stratigraphic and paleogeographic implication.– riv. ital. paleont. strat., 113/1, 21–42. velić, i. (2007): stratigraphy and palaeobiogeography of mesozoic benthic foraminifera of the karst dinarides (se europe).– geol. croat., 60/1, 1–114. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeogr. palaeocl., palaeoec., 220, 333–360. manuscript received january 31, 2012 revised manuscript accepted february 16, 2012 available online june 29, 2012 sokač et al.: taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia) geologia croatica 183 geologia croatica 65/2geologia croatica 184 plate ix 1–8 falsolikanella? teakolarae (radoičić et al.) n. comb. 1 longitudinal section, slide sb–17e2/1, x17. 2 longitudinal, partly tangential section, slide sb–17e2/1, x22. 3 tangential–oblique section, slide sb–17e2, x22. 4 oblique section, slide sb–17e2/3, x22. 5 tangential–oblique section, slide sb–17e2, x34. 6 tangential section of two whorls, slide sb–17e2/3, x22. 7–8 tangential sections, fig. 7, slide sb–17e2/2, x34; fig. 8, slide sb–17e2, x34. sokač et al.: taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia) geologia croatica 185 geologia croatica 65/2geologia croatica 186 plate x 1–9 falsolikanella? teakolarae (radoičić et al.) n. comb. 1 tangential–oblique section, slide sb–17e2/3, x34. 2 longitudinal section, slide sb–17e2/2, x17. 3 longitudinal–oblique section, slide sb–17e2/1, x17. 4 tangential section, slide sb–17e2/1, x34. 5 oblique section, slide sb–17e2/2, x34. 6 oblique section, slide sb–17e2/2, x22. 7 tangential–oblique section of two whorls, slide sb–17e2, x34. 8 transverse, slightly oblique sections in the whorl level, slide b–17e2/1, x22. 9 oblique section, slide sb–17e2/3, x22. sokač et al.: taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia) geologia croatica 187 geologia croatica 65/2geologia croatica 188 plate xi 1–12 falsolikanella? teakolarae (radoičić et al.) n. comb. 1 fragments of differently oriented sections, as well as section of alveolina sp., slide sb–17e2/4, x14. 2 oblique section in the whorl level, slide sb–17e2/3, x34. 3 fragments of differently oriented sections, slide sb–17e2/4, x22. 4–5 tangential sections of branches from the one whorl, slide sb–17e2/2, x34. 6 longitudinal sections of separate whorls, slide sb–17e2/2, x34. 7–8 longitudinal sections of separate whorls, fig. 7, slide sb–17e2/3; fig. 8, slide sb–17e2, x22. 9 tangential section of a whorl, slide sb–17e2/1, x22. 10 tangential section of the proximal part of a whorl, slide sb–17e2, x22. 11–12 tangential–oblique sections of branches from the same whorls, fig. 11, slide sb–17e2/1; fig. 12, slide sb–17e2/4, x34. sokač et al.: taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia) geologia croatica 189 geologia croatica 65/2geologia croatica 190 plate xii 1–2, 3a, 4–5, 6a, 7–8, 9a falsolikanella? macropora n.sp. 3b praturlonella salernitana barattolo. 6b, 9b clypeina lucana barattolo & romano. 6b clypeina bucuri barattolo & romano. 1 fragments of different sections, slide rak–40a/19, x14. 2 oblique section, slide rak–40a/23, x14. 3 a) falsolikanella? macropora n.sp.; b) praturlonella salernitana barattolo – transverse sections, slide rak–40a/8, x17. 4 oblique sections at the whorl level, slide rak–40a/25, x14. 5 transverse sections at the whorl level, slide rak–40a/25, x14. 6 a) falsolikanella? macropora n.sp.; b) clypeina lucana barattolo & romano and clypeina bucuri barattolo & romano – transverse sections, slide rak–40a/14, x14. 7 fragment of an oblique section at the whorl level, slide rak–40a/11, x 14. 8 oblique section at the whorl level, slide rak–40a/4, x 22. 9 a) falsolikanella? macropora n.sp. – fragment of an oblique section; b) clypeina lucana barattolo & romano – transverse, slightly oblique section, slide rak–40a/27, x17. sokač et al.: taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia) geologia croatica 191 geologia croatica 65/2geologia croatica 192 plate xiii 1–8 falsolikanella? macropora n. sp. 1 oblique section, slide rak–40a/11, x14. 2 oblique section, slide rak–40a/14, x14. 3 transverse–oblique section, slide rak–40a/19, x14. 4 transverse–oblique sections, slide rak–40a/29, x14. 5 oblique section, holotype, slide rak–40a/11, x14. 6 parts of transverse–oblique sections, slide rak–40a/21, x14. 7 oblique section of a part of the whorl, slide koz–27, x 34. 8 oblique section, slide rak–40a/19, x 17. sokač et al.: taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia) geologia croatica 193 geologia croatica 65/2geologia croatica 194 plate xiv 1–11 falsolikanella? macropora n. sp. 1–2 tangential sections, fig. 1, slide koz–6; fig. 2, slide koz–10, x34. 3, 6–7, 10–11 oblique sections of separate whorls, fig. 3, slide koz–1; fig. 6, slide rak–40a/2; fig. 7, slide sb–17c2/6; fig. 10, slide rak–40a/4; fig. 11, slide rak–40a/2, x22. 4 oblique section, slide sb–17c2/4, x22. 5 longitudinal section, slide sb–17c2/4, x22. 8 longitudinal section, in the upper part fragment of a tangential section, slide koz–6, x34. 9 longitudinal section, slide sb–17c2/4, x 22. sokač et al.: taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia) geologia croatica 195 geologia croatica 65/2geologia croatica 196 plate xv 1–6 falsolikanella? macropora n. sp. 1 longitudinal–tangential section, slide koz–28, x22. 2 oblique section, slide sb–17e2/6, x17. 3 deep tangential section, slide koz–23, x22. 4 oblique–tangential section, slide koz–12, x22. 5–6 tangential sections, fig. 5, slide koz–11, x22; fig. 6, slide sb–17c2, x17. sokač et al.: taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia) geologia croatica 197 geologia croatica 65/2geologia croatica 198 plate xvi 1–10 falsolikanella? macropora n. sp. 1 longitudinal, partly deep tangential section, slide koz–15, x22. 2 parts of transverse sections at the level of a whorl, slide sb–17c2, x17. 3 tangential section of the distal part of the thallus, slide sb–17c2/6, x22. 4 transverse section, slide sb–17c2/6, x22. 5 transverse section, slide sb–17c2/3, x17. 6 oblique section, slide sb–17b2/6, x17. 7 oblique section of part of a whorl, slide sb–17c2/2, x17. 8 transverse section at the whorl level, slide sb–17b2/4, x22. 9 part of the oblique section at the whorl level, slide sb–17c2/6, x22. 10 longitudinal section at the whorl level, slide sb–17c2/6, x22. sokač et al.: taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia) geologia croatica 199 geologia croatica 65/2geologia croatica 200 plate xvii 1–12 falsolikanella? macropora n. sp. 1 oblique section, slide sb–17e2/13, x17. 2, 5, 7, 11 parts of transverse–oblique sections at the whorl level, fig. 2, slide sb–17e2/13; fig. 5, slide sb–17c3/4; fig. 7, slide sb–17c3/4; fig. 11, slide sb–17c3/4, x22. 3, 6 oblique sections, fig. 3, slide sb–17e2/5; fig. 6, slide sb–17c3/3, x22. 4, 10 transverse sections at the whorl level, fig. 4, slide sb–17e2/8; fig. 10, slide sb–17e2/11, x17. 8–9 transverse, slightly oblique sections, fig. 8, slide sb–17c3/4, x34; fig. 9, slide sb–17c3/3, x22. 12 tangential section in the proximal part of the whorl, slide b–17e2/17, x22. sokač et al.: taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia) geologia croatica 201 geologia croatica 65/2geologia croatica 202 plate xviii 1 falsolikanella? teakolarae (radoičić et al.) n. comb., oblique section. yellow colour and the fibrous structure of hyaline calcareous envelope of branches are clearly visible, slide sb–17e2/2, x34. 2–3 falsolikanella? teakolarae (radoičić et al.) n. comb., oblique–longitudinal section with visible reddish-brownish pigmented outline of the calcareous thallus, slide sb–17e2/1, x22. 4 falsolikanella? teakolarae (radoičić et al.) n. comb., tangential section of two rows of branches with characteristic fibrous structure of the hyaline calcareous envelope, slide sb–17e2, x34. 5–6 falsolikanella? macropora n. sp., fig. 5 – oblique section of the holotype with light grey to yellowish colour of granular sparite calcareous skeleton; fig. 6 – detail of granular calcareous structure, slide rak–40a/11, fig. 5 x14, fig. 6 x34. 7 falsolikanella? macropora n. sp., fragment of tangential section with the clearly visible granular structure of the calcareous skeleton, slide sb–17e2/8, x34. 8–9 falsolikanella? sp., oblique–longitudinal sections, fig. 8, slide sb–17e2/16; fig. 9, slide sb–17e2/15, x22. 10–12 acicularia sp., different sections, fig. 10, slide sb–17e2/3; fig. 11, slide sb–17e2, fig. 12, slide sb–17e2/5, x54. sokač et al.: taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia) geologia croatica 203 geologia croatica 65/2geologia croatica 204 plate xix 1 alveolina cremae checchia-rispoli, axial section (scale = 0.5 mm). 2 alveolina pinguis hottinger, axial section (scale = 0.5 mm). 3 spirolina sp., unidentified miliolids and alveolina sp. with diagenetically altered test walls (scale = 0.5 mm). 4 periloculina dalmatina drobne and alveolina sp. (scale = 0.5 mm). 5 alveolina sp., equatorial section with triplet embryonic apparatus showing dissolution of the younger whorls (scale = 0.2 mm). 6 nummofallotia cretacea (schlumberger), axial section (scale = 0.2 mm). 7–10 calveziconus lecalvezae caus & cornella; 7 and 8 subaxial sections, 9 basal section, 10 oblique section (all scales 0.2 mm). sokač et al.: taxonomy and stratigraphy of an algal assemblage in palaeogene deposits of the northern foothills of mt. biokovo (southern croatia) geologia croatica 205 geologia croatica 65/2geologia croatica 206 geol. croat. 49/2 2 17 · 226 8 figs. i i tab. zagreb 1996 i expansion of the old oil field of bunjani on the basis of geological reinterpretation niko filipovic key words: reservoir developm ent, geolog ical rei n­ te rpre tation , sava depression. abstract duc \0 the non-de f ined contouring of the blllljani field and l h e posi tive exploration well jo-2 at the squ \hwcs\ of ihe field outsi de the concession, :i need for the geological reinterprewtion of the arca wa" discovered in order to solve the petroleum-geological rel ationships in the arc;!. and determine field ex pansio n and reservoir contouring in a more qu al itati ve way. the fccc nt geo logical reinterpretati on was per­ famed 011 the bas is of a rev iew of all avai lable data from the exist ing we lls, lhe res ult s of field dcvc]opmcl11 10 lhe present , the int erprcta ­ tion of ncw scismic profi lcs and thc knowledge of the pctrolcum-gco10g ic;1i re l;lli onsh ips in [he pan of the basin previ ously acqui rcd . the rcinterprctati on proved to be justified ,md i1 result ed ill the detennin<l­ ti on of ncw wc ll locati ons and their drilling in 1993 and 1994. in thi s way, the field ex panded towards the southwest and th c north . with the ncw reservoir geometry, beller quality data of the reservoi r char­ acteris tics, anti lyses obtai ned from the new well s, together with the reintcrpretation of clect rie log analyses obtained from olel wells, the reserves of oi l have been increased by 3 1.4%. 1. introduction t he objec ti ve o /" this paper is to explain ho w lhe geolog ical re inte rpretation (using the available dala and with the minimum of investment) has enabled expan ­ s ion o r the o ld bulljani oil field and secured the suc­ cessful continuation or petroleum production. in o rder to revitali se old oil field s with a low pror­ itability margin , (o r which the bunjani is one sample), at tempts have been made to renew development ac tivi ­ ties . the essen tia l targe t was to make profitable use of the available data and to define the possible ex pansion 01" the oi l field with the minjmulll cost and with the use of standard development practices. in view of the above c riteria attent ion was directed to the possible expansion o r undepicted parts or the rcservoir, or the discovety of new hydrodynam ic oil saturated bodies, as well as olher development act ivi ti es which would increase o il rccov­ cry from ihe old part o f the oil fi e ld. the first step was the geolog ical reinterpretation which resulted in drilling o f the new productive wells , the oil fi eld expansion and an increase in the petroleum reserves. ina -natbplin, subicev;\ 29, iir 10000 zag reb. croatia. proceedings kljllcne rijcci: razrada lei ista , geoloska re int erpreta­ cija, savska potolina. saietak zbog nedefiniranog o kon lllrenja po tj a bunj ani i poziti vllc istrazne busoline jo-2 na jugozapad u polja, izvan konces ije, uk azaja sc po lrcba zil geoioskom reinterpretacijol1l s c iljcm kva litctn ijeg tjesavanja naftnogeolos ki h odnosa ovog podrucja, prosi rcnja polja i okollt urenja leiisla. najnovi ja gcoioska rein terpret acija izv rscna je na temelj u pono\,11og preglcda svih raspo loliv ih podat aka iz poslojeciil busotina, rezu itata dosadasnjc razrad e lezista, rczu llata intcrprelacije novosn imlj enih seizmickih prorila , te dosaclasnji h sawanja 0 naft no­ geol o .~kim ocinosima log dijela potoline. rci nl erprctacija sc pokazala opravdanom i rezultirala lociranjem i izradom llovih b ll.~o tina u 1993. i 1994 . godini. time je poljc prosireno preilla j ugozapadu i sjevcru . s novom gcomelrijom leiista i pros irc nj em po lja, ie kv~ lit ctnijim podac ima ailaliza i svojs t(lva kol e kt ora, s nov ih i starill busotina , povccane su rezerve nan e za 3 i .4''10. 2. review of exploration operations to date the bunjani oil fi e ld be longs to th e pannonian region of the sava depression (fi g. i ) . the struc tural closure of " krii", where the bunjani oil fi e ld is located, was discovered by the rcgional gravimetric survey per­ formed by the german group "scismos" from hannover between 1940-1942. since the whole area is covcrcd by dilu vial and allu­ via l deposits, it has been impossi ble to carry out s llrf~lee geological mapping. hcnee during i 94 l -1942, 20 sha l­ low s truct ura l wells were d rilled to confirm the geo­ physical resuits. onl y onc of these well s ($-12) is locat­ ed wi thin the bunjani oi l fic ld . based on the grav imetric survey and struc tural weli s, the fi rst deep ex ploration well was drilled in 1948, which d iscovered oil at sume­ cani. for thc purpose of furth er expansion o r the s ume­ calli oil field (kriz), thc deep expl orati on well bni was drilled in autumn 1951. thi s well pene trated bcds coil ­ firmin g the prcsence of an oil reservo ir in ihis area. t hi s is how the bunjanl oil field was d iscovered , which pro­ duccd oil of a different quality 10 that found in the kriz oil fi c ld. 21x =~"l=~1 -------....bo ,,10 --t---t---t---+• zagreb i' i' j "eoo" i 1---1-----1... klostar -! je1:e~o _ . i t ..... _, .... kr i • ~'~. \ bunjani : --+----'.+--"<11..,4 ivant ~"~i zutica .... ~ : vezisce -+----' ~wu ! 7.5km t l mr am or brdo ... o il fields _ bunjani o il field _ o il-ga s fields f-ig.! location map of tile fields in the nonh-west area of the sava depression. by 1964,61 wells were drilled through the field, without the field contours having been precisely defined. the field was put into production in 1952. between 1964-1979, there were no exp loration or development operations. in 1979, in the southwestern part of the field, (outside the concession) , the jo-2 f-i g. 2 map of all [he bunjani field reservoirs with marked expansion. geologia cromica 49/2 exp loration well was drilled, which was pronounced negative, but which later produced good results during subsequent testing. it offered new possibilites for field extension lo the southwest beyond the boundaries of the production field. with this aim development activities were resumed in 1992. 3, geological reinterpretation undefined field contouring and the positive explo­ ration well jo-2 (1979) have prompted the resumption of development activities on the ficld. on first review­ ing the available field data, it became evident that the geological reinterpretation was necessary in order to bettcr dcfine the petroleum-geological relationships of the area, delineate an area for field extension and to fac ilitate precise reservoir contouring. the last available integrated geological presentation detailed 41 drilled wells (1955) in the archives of the tna-naftaplin trade and techni cal papers and record s library, and in the published paper (galoyic, 19511953). in addition to the above mentioned geo log ical data, there are also available anonymous maps prepared at the reservoir top but which contain insufficient infor­ mation, based on 61 drilled wells. three scismic lines (2 0) of mediocre quality and standard processing were legend • o • producing wells dry wells deviated well exspandeo field area along the reservoirs 1+ 11 , iii , iv arid v old part of the field q concession a·a' line of geological cross section 4 filipovic: expansion of the old oil field of bunjani on the basis ofgeologieal r.e interpretation 219 fi g . 3 c ontour map of the top of the "[ii " reservoir. shot on [he field. wireline logs eel, ml) from 61 wells were also used, as well as the results of laboratory analysis and data on the field production history cover­ ing [he years from 1952101992. after having defined the potential prospectivity of the field extension, the next question to discuss was the profitability of investment in further development oper­ ations, in respect of the field size and the oil reserves present within the old part and possible extension there­ of. the objective was to define the field extension and to put new wells in production with the minimum finan­ cial investment, using thc available data and standard practices usually applied in geological reservoir devel­ opment . exploration began with the shooting of 10 short seismic lines (2d) (total of ca. 40 km) across the field and marginal parts, covering principally the possi­ ble ext ension areas. the survey and interpretation proved to be justified. based on the interpretation and synthesis of all geological data, including the jo-2 well, the locations were proposed and the positive wells en02, bn-63, bn-64, bn-6s~ and bn-67 were drilled, thereby extending the rield to the southwest, and bn-66 which initiated extension to the north (fig. 2). geological reinterpretation was based on the renewed analysis and inteq)j'etation of all available well data (geological monitoring records, dst; physical and geochemical rock analyses; biostratigraphic, petro­ graphic and sedimentologic assignments; oil and water scl·53 bn·16 o legend • oil wells • water wells o impermeable {wjtllou! reservoir rocks) c:j oil [zj water d impermeabu~{w'thou t reservoir rocks) .~~ . .::j deviated well oil·water contact isobath • •• •••• • probable sandstone pinch·out ~ normal fault ~ reverse fault acc to seismics :: :>< :: supposed reverse acc to seismics ® tectonic block o~1....e.~~5'm scale analyses, well completion results, reservoir pressure and temperature measurements, as well as field produc­ tion history), and in particular revised the renewed wireline log correlation. evaluation of the physical rock properties for the bunjani field was performed using porosity and water saturation data obtained [rom wireline log analyses and laboratory analyses of rock samples from conventional cores. e-iogs from recent wells (bn-62, bn-63 , bn-64, bn-6s , bn-6sa, bn-6s~ and bn-66) have been per­ formed within an integrated programme. this included different resistivity measurements (ml, d1fl, dll, el), acoustic logs (albf-ie), natural radioactivity mea­ surements of the rocks (gr), density and apparent porosity measurements (cdl/cnl) and formation dip measurements. this data combined with the laboratory core analyses and geological monitoring data, provided a good basis for evaluation of the physical parameters of thc reservoir. for this purpose an "epilog-era" computer program set was used. lithological assign ­ ment and porosity calculation were mainly de fin ed from cdl/cnl/gr logs. the new reservoir geometry was defined by reinter­ pretation, excluding some of the reservoir rock bodies originally believed to be oil saturated, but which in fact have been water saturated or which are not reservoirs. until now, the bunjani field had three classified reservoirs ("m", "k" and "tg"). during the gcological 220 fig. 4 contour map of the top of the ··v" reservoir. reinterpretation and after drill ing the new wells, four reservoirs we re identified (i+i1, iii, iv and v). the reservoir classification was based on data synthes is, revised correlation of wireline logs, results of analyses of open interval tests in the wells, well pressure mea­ surement data and the production history. a synthesis of the utilised data, with interpretation of the newly shot seismic lines, together with the absence of preeoncived ideas and the aim of extending the field resulted in a new picture of the structural and tectonic relationships, reservoir division and contours involved. by including the belier quality data for each new drilled well, a new geological scenario was pre­ pa red for the bunjani field and the extensions to the sout hwest and north were defined (fig. 2) . with the field extension to the sou thwest over the reservoir ttl (fig. 3) and the reservoir v (fig. 4), the presence of separate hydrodynamic units has been iden­ tified. these units have higher reservoir pressu res (nearly hydrostatic) , which are independent in respect of thc old part of the field (excepting the bn-2 well area), with the trial production of the new comp leted wells. the bn-62 we ll (20 m'/day of water free oil), bn-63 well (is m'/day of oil) , bn-6s~ (25 m'/day of waler free oi l) and bn-67 (35 m3/day of water free oil) produce yields well above the average of the old weus. the eontouring/bounding of the well to the southwest at reservoir hi is not fina l. in this geological scenario, the gcologia croatica 49n • oil well • water well 0 dry well d 0" d water d impermeable (w ithout reservofr rocks) .-'.0 deviated well oilwater contact isobath reservoir rock properties disappearance bn-55 = normal fault • ~ reverse fault ace_ to seismics ::c :>c :: supposed reverse acc to seism ics tectonic block reverse fault is anticipated as a boundary only on the basis of 2d seism ic lines which are characterized in this area by extremely dispersed seismic rcflections, which implics that the seismic interpretation is also unsafe. the extension to the north with the new well bn-66, is based upon contouring of all four wells from the old field area (fig. 2), and that of reservoirs i+ll (fig. 5) in particul ar. based on the resu lt s of the reinterpretation, it was proposed that the hydraulic fracturing method for reser­ vo ir rocks should be used in order to enhance the pro­ ductivity of 12 wel!s. three fracturings were performed (bn-40, bn-s7 and jo-2) and good results were obtained. the production history to date indicates tha t the gas­ oil energy and thc waler environment elast ic energy are used in reservoir exploitation. an overview of the oil production to date and future predictions as the result of the geological reinterpretation, are shown in fig. 8. the proven results of the geological reinterpretation have opened the possibility for yet another extension of the field to the southwest (across rese rvoir til), where the fault boundary is also uncertain to the north across reservoir 1+11. there is a sha llo w dcpth of soi l to the north, and it is necessary to es tab lish with more preci­ sion the pinchout boundary of the oi l-bcaring sand­ stonc. it is absolutely necessary [or the fi nal defini tion of the reservo ir boundaries to carry out the seismic surfilipovic: expansion of ihe old oil field of bulljani 011 ihe basis of gcologic<ll reimerprelalioll 221 ° kr_59 bn·63 o jo·2 o 00010.2 0 304 05km scale fig. 5 contour map of the top of the ·'1+11 " reservoir. bn·24 " bn·14 o bn-2b o vey and 3d seismic interpretation togcther with a rea l­ istic evaluation of furt her deve lopment operations in terms of cost-effective feasib ility. 4. geological structure of the field the description of the geological structure of the field has been prepared on the basis of known data obtained during exploration and development opera­ tions to date with special reference to the results of the geological reinterpretation. 4.1. stratigraphic relations the stratigraphic age of separate beds of the bu­ njani field has been established on the basis of palaeon­ tological analysis, supe:·position, lithological character­ istics as well as the wircline log corre lation, and also the results of the regional correlation of lithostrati­ graphic unils (simon. 1973). based on the available data, the following strati­ graphic units can be distinguished (figs. 6 and 7) in the bunjani field area: quaternary: represented by diluvial beds within the yellow clay facies, with loess in places in the base. pliocene (romanian and dacian): pliocene beds developed within the facies composed of variegated clays , coarse grained sands and argillaceous sands. no cores have been recovered from these beds, hence there is no palaeontological data available. 0 8 r>16 legend • oil wells • vater wells o impermeable (without reservoir rocks) o wells in areas without reservoirs doll c::5] water d impermeable (without reservoir rock"1 ""r .,(j deviated well oil-water contact -isobath •• ••• • probable sandstone pinch·out ~ normal fault o tectonic block t-50 bs-55 l,---------~----.j bn·47 o bn-56 " ----~8~'.--.'"~. ~5-----­ o ~~-27 86'-38 upper pontia n: the upper pont ian beds are char­ acterized by the alterna tion of gray and brown argilla­ ceous marls, marly sands and sands. t he fauna has not been specifically defined, but limllocardides wi th large shells and collgeriae with c. rho!1lhoidea and c. zagra­ biehses species have been observed. there was no hydrocarbon present. the upper pontian beds were deposited in a concordant relationship with the lower pontian beds within the facies of grcy marls and local clayey marls. lower pontian: palaeontological macrofossil dete­ rm ination has been performed only during geological monitoring of wells where specific specimens of the genus paradacna with p . ahichi species were identi­ fied . no hydrocarbon presence was found within these beds. upper pannonian: the lithological composition of this strat igraphic member is characterised by greyish marls with slightly arenaceous marls with calcareoll s marl intercalations in places. this member exhibit s strong uniformity across thc study area. the fauna has not been specifically determined. howcver, congeria spp . fragments and limnocardids dcbris have been determined in the field. there is no hydrocarbon reser­ voir within thcse beds. lower pannonian: this stratigraphic member rep­ resents a facies composed of hard, white to grey cal ­ careous marls and argillaceous limestones. these are frequently interlayered with thin sandstone bcds. usual­ ly, marls are fracturcd. there is a freshwater fauna 222 stratigraphic classification (steininger, rool. muller 1987) w ~ o\ tj if> stage/ age if> a: ~u) \ ~ :r w ~ " 1-0: llj uj europe 0 a: q lii \ do\ <xl <! " " 8~t \ ~ ~ general local if> w ~ ~ if> o~ ~ \ lu i classification classification ~-g: , a: \ (tethys) {central if> :j! paratethysi o -holocene -9 quaterholocene pleistocene 0 ~ nary _ pleistocene i t~ piacencian ] t g romanian pi, zanclean >~ :::::i 5 ~ 0.. dacian messinian ee 3 ~ w ponti an "i f<! i ~ ee tortonian 1 w 10 i pannonian i z w ~ w " 11.5 i z me (!) serravallia sarmatian w -ll w ~ 136 ~ 0 ° ii ° 0 " 15 ;; w baden ian m, ~ 0 langhian ~ z 16.5 --~~ karpat1an m3 i 2 ottnangian fa, ~ ~ burdigalian ---, a: 19.0 --:i <! , w , eggenburg m, ~--l aquitanian w egerian? oim chadian kiscetlfan composed or iimneids, planorbids and ostracods. no hydrocarbon presence has been identified in these beds. sarmatian?, badcnian, karpathian, oligo-mioce­ ne?: the lithological composition of this group of stra­ tigraphic members is characterized by an extremely va­ ried sequence of clastic sediments, beginning with coa­ rse deposits directly overlying the basement (breccias, granil ic debris, breccio-conglomerates and conglomer­ ates) , followed by conglomeratic sandstones, marly sandstones and marls. in the overlying layers there is also a calcareous component represented by calcareous column of bunjan1·9 (bn · 9)wal depth (m) lithology :-:_:_:1 cla y :-=-~ clay maal ~-~ . ~':'j sandy marl :-:-:-:1 marl -:_ -_] limy marl <.:«<.:.:j sandstone 0 '00 '00 ·~~:.~:..:; i conglomeratic sandstone ~~~:5.~ conglomerate ~ ~ granit[ gcologi~ croalica 49/2 fig. 6 correlation of stratigraphic units of the i3unjani field with the geological column of the 811-9 well. marls and sandstones. it has been impossible to subdi­ vide the stratigraphic members within this sedimentary sequence due to the high degree of lithological hetero­ geneity and considerable lateral changes, as well as due to their poor fossil content. no fossil remains were found in the breccias and conglomerates. the age was determined on the basis of a fauna which was found in the marl, and less frequently in the sandstone [ayers. within these sediments 4 oil reservoirs have been identified (1+11, iii, iv and v), whereby the reservoir v also includes a part of the "basement". " '" ~ o o o ,g [ o ~ " :: o· o '> " 2, " " 2. §. '" o 0: sw .. ,~, ] ® ·100 ' ~ ,. , + 0 ii ~ « '> ~~ w~ ~. -100 ., 0 w ~~ of:::i « ;)0 "' j0.6 q 300 i \ '00 ] """ ~, "'''''~ w -500 _ z \ w u lower \ "' i 0 pontian .,,, n ~ p..j!~~~ lo' .... er pannonian s"oeni1o.n k.l.rpatii\n <0' ] str"tigraphic ·300 undetermined -100 0 1\ lop , 4j i n> horizontal scale b~2 h"14686m 8n-54 h"13945m 8n-19 h" 14792m ~~:t'i\i '.:,::i! t;! sand ~ ", ~ ~clay ...... "" ... [-: .... : : clay marl i ~-~·~-~ sandy marl [-=-=-= marl '" __ ...::.: limy marl :::··· ·: :·1 sandstone ....... bn-j5 h:130 20m · ;.~:·~:.~i conglomeratic sandstone ~ conglomerate ~-%;:; rockfall breccias ~granite . . 80-46 h:l1j.69m ~oil ~ ~ ~>;" water 8n-44 ne h=i04 dim c=j impermeable (marl) j'i i4 "ii impermeable (granite) c ~ lower pannonian deposit c==] upper pannonian deposits c= lower pontian deposits c= upper pontian deposits tijj normal fault ~ reverse fault ~~ supposed reverse fault __ uncoformity ~ ~ ~ ] c· o s,. " o o 0: 2 ~ ~ s, " o ~" ::" g ~ ~ ;;." s, ~ g [ ~ § .; il ~ g" ~ ~ w 22·1 otl fteld: bunjani 30000 ""''' .-• 20000 +-~ 1 ~ 15000 past o il production 10000 sooo 0 " " , h ,~ -1--+-+ ~ , ~ ~ ~ ~ * ~ ~ g ~ ~ ~ ~ , v:"a qs t he " base m ent" (s tratigraphi call y und etermi­ ned): composed of weathered and frac tured cataclas­ tici zed, hydrothermally al tered granite and gnei ss . granites occur within the overlying beds of the produc­ tive area, while gneisses occur in the peripheral parts in depth. calc it c may usually be found depos ited in fi s­ sures . in those areas where the frac tured "basemen t" lies in a structu rall y favourable posit ion, an oi l reservoi r was form ed. 4.2 local tectonic and structural relations hips in the most recent geological reinterpretation of the ficld. the solutions involved wit h the structura l and tec­ tonic re lationships we re based on the in terpretation of new se ismic lines and correlation of well data. general­ ly, the bunjani oil field is separated from the southwest deep area by a fau lt zone, where tectonic blocks sub­ s ided in a "staircase slope" [or over 1000 m. structura l­ ly, the rield is represented by a faulted monocl ine trend­ in g nw-se. the monocl ine plunges to the sw at an angle of 10°. some of the faults have been identified through the absence of some of the layers in wire li ne record s and from the results of seismic line in terpre ta­ tion , and others have been anticipated. the bu njani fi e ld has been divided in 6 tec tonic units . the fau lt s were importan t for the reservoir oil accumulat ions. rep­ resenting barriers in places, as a resu ll of which differ­ ent hyd rodynamic condi ti ons were formed, hence the water-oil contac t is a t various levels wi th in sepa rate blocks. 4.3. geo log ica l description of the reservoirs in te rms of their stra tigraphic assignment and li tho­ log ica l characterist ics , the reservoir rocks of the bu­ njani fi e ld arc represented by two d ifferent reservoir types : a) " the basement" consisting of eataclasticized future oil production geologia croallca 4lj/2 fig. 8 oit production of the bunjani fi eld past, present and future (based on predic­ tions from thi s study). and hydrothermally al tered gran ite and gneiss, b) con­ glomerates, breccio-conglomerates, breccias of granitic debris, and miocene sandstones (probabl y also o ligo­ miocene) . the cap roc ks are marly sedim ents . the pet ro leum -geolog ical re lationships, in respec t of the ir occurrence, distribution and lithologica l characteris tics, <.ire moderate ly comp lex withi n th e ind ividua l strat i­ graphic members. th e rese rvoir data summary of the bunjani oi l field is shown in table i. reservoir l+1i: com posed of fin e 10 eoarse~ grained, poorl y cemented, quartz-micaceolls sandstones and conglomeratic sandstones . the reservoir is of st rati ­ g raph ic type, deli neated by a lit hologica l bou ndary marl ificatioll and pinchollt , and by a tectonic boundary (fig. 5). reservoir iii: in genera l, reservo ir rocks of reser­ vo ir iii are fi ne to coarse grai ned, poo rly to medium cemented quartz-micaccous sandstones and conglomer­ ate sands tones . reservo ir beds are as a ru le thin and di sco ntinuous and intercalated wit h marl s . the reser­ voir is strat igraph ic in type, de lineated by a li thological and tectonic boundary. ]t is characterized by zonal mar­ lifieation and pinchouts in combination with tectonic boundaries faults, with separate water satura ted zones (fig. 3). reservoir iv: also represented by zonal evolu tion. the reservoir rocks are composed of somewhat larger coarse-gra ined clasts, consisti ng of coa rse-g rained sandstones, conglomeratic sandstones, and sandstones with fragments of large granit e pebbl es . they were depos ited in thin disco ntinuous laye rs and laminates . the reservoir is strat ig raphic in type, delin eat ed by a litholog ical and tectonic boundary. the reservoir boun daries have sim il ar characte risti cs to those of rese rvoir nt, since the resc rvoir rocks were deposited with in the same sedimentary cycle. reservoir v: this is formed of two rcservo ir types : a) conglomerates, breccia-conglomerates. brecc ias of filipovic: exp;ulsion o f the old oil field of bunjani 011 the i3nsis of geological re inlcrprctation 225 discovery date: discovery well: productive formation: depth of formation: 1951 bni preeec 700 m (average) reservoir type : reservoir age: [+ j1 , 1[1 and iv stratigraphic with the lithologic and tectonic boundaries v stratigraphic-massive type bounded by the impermeable zones karpathian , badcnian, (oligo-miocene?) depositional environment: marine and fresh-water drive mechanism: depletion drive and water driv e source rock: cap rock: miocene and pliocene marly sediments in th e sava depression marly sediments pre-reservoir: gran ite and gneiss orig inal res. pressure: present res. pressure: 67.2 bar (9 .7 bar/loom) (reduced to the weight level of -579.0 m) different along the reservoirs orig. oil / water contact: different in lhe reservoirs and tectonic blocks or withollt contact rock properties: ave rage porosi ty : (pans of unit) lnil ia l water saturation: (pans of unit) 1+ 11 0.139 1+11 0.405 iii 0.130 iii 0.409 iv 0.122 iv 0.409 v 0.111 v 0.424 average permeabi l it)': reservoir temperat ure: insufficient data ss.2°c (4.55 °c/ioom) a vernge oil propert ies: volume mass of oil (20 dc): volume ratio of oil (bo): viscosily (20°c): para fin colltenl: consolidation point: r75 kgim 1 j .074 m3/m 3 2 1.6 mpas 8.00% il oe table i reservoir data su mmary of the bunjani oil field. granitic debris, conglomerate sandstones and b) weath ­ ered, fractured catac lasti cized and hydrothermally altered granite and gneiss ("basement"). most of the well s penetrated the "basement " whereas in several of the wells the drilling te rminated in the basal miocene sed im ents and therefore the reservoir v was not com­ pletely uncovered. the basa l sediments as the integral reservoir pans, are transgressively overlying the "base­ mcnt". they havc variable thickness, and in some plaees they are comp letely absent, depending on the palacorclief. these sediment s are composed of pebbles and granite fragments, and to a lesser extent gneiss. the pebbles vary in size. roundness and sorting arc poor. large pebbles arc frequentl y incorporated into coarse­ grained sandstones. the matrix is argillaceous. in lhe southwest, newly extended part of the bunj ­ ani ficld, these reservoir rocks consist of granite debris breccias, unevenly cataclasticized with a dense mineral compou nd matrix consisting of sericite, chlorite, feldspar and quartz. rare sedimentary bodies composed of si lty-grained fossiliferous marl , with traces of coal, can be found within these breeias . the reservoir v (fig. 4) is of mixed type (massive and strat igraphi c), bounded by zones with no reservoir properties and by fault s wh ich are probably barriers considering the different oil-water contacts within the separate tectonic blocks. 5. conclusion based on the geological reinterpretation carried out on the old bunjani oi l field, lhe following conclusions may be drawn: i. the geological reinterpretation was justified and per­ formed with the minim um financ ial investment (the cost of approximately 40 km of seismic lincs and the work of the geological project manager). 2. standard reservoir develop ment practices wcre used with the available data during the reinterpretation. 3. inst ead of the three reservoirs discovered to date , four reservoirs were identified. 4. the evaluation of the reservoir paramet ers for the old field area was morc realistic , since it was based on tile reservoir rock analyses from new well data from which the oil reserves were recalculated. 5. the dete rmination of the structural and tectonic rela­ tionships through interpretation of the new seismic 226 lines result ed in the be tter evalu ation of rese rvoir cont ouring/bounciaries. 6. the field was cx tcndcd to the southwest and north , wh ich increased thc rccoverable oi l reserves by 31.4%, and fac ilitates the success ful continuation o f oil producti on between 1995-2014. 7. the fie ld extension to southwest identified reservoirs with hi gher formation pressures which are indepen­ dent o f the old pan of the field and the eruptive well productio n. the extension to the north is based o n the reservoir contouring from the old ficld. 8. the reint erpretation also proved the suitabi lit y o r hydraulic fracturing of reservoir rocks as a means of inc reasi ng produ ctivit y of the well s bn-40 , bn -57 and jo-2. 9. the possi bility has been opened for further ex tension o f the fie ld by application of 3d seismics assum ing a detailed study proves the cost effec ti ve feasibility of slich a projec t. geolog ia cro:liica 49n 6. references galoyic, s. (19511953): prilog geoloskolll pozna­ vanju strukturc kri i.geol. vjesnik, 5-7, 255-272. st eininger , f. , rogl, f. & m uller. 1-1. (1988) : correlation of central paratc th ys, eas tern paratcthys and mediterranean neogene stages .tn: royden, l.h. & i-lory ati-i , r. (cds.): the pan­ nonian basin. aapg memoir, 45, 79-8 1. simon, .t. (1973): 0 nekim rcz ultatim<l reg ionalne korclacije litostratigrafskih j eclini ca ll jugozapad­ nom poclrucju panon skog bazena. na ft a, 24/12, 623-630, zagreb. 06_szilagy.indd 77 sebők szilágyi and geiger: sedimentological study of the szőreg-1 reservoir (algyő field, hungary)... � ab stra ct the paper presents a 3d sedimentological characterization of a delta plain reservoir. the analysis started with detailed core description studies focusing on the genetic interpretations of the sedimentary structures and multivariate statistical analyses (including q-mode cluster and r-mode factor analysis), of the sporadic grain-size distributions. these results made the depositional processes of channels, bar-crests and crevasse splays probable. by calibration of the well log responses to the cores with total core recovery, we were able to identify two types of vertical facies transitions: (1) mouth-bars and channels; (2) crevasse splays, crevasse channels and minor mouth bars. in addition, a vertical sequence of a relative thick distributary mouth bar was also recognized. lateral extension was determined by contouring the sand content on surfaces parallel to the upper time horizon. on these surfaces, the sand content and porosity grid systems facilitated the use of an unconventional 3d geo-cellular modelling approach for both well-logporosities and sand contents. since vertical depositional facies were extended into the 3d, rock bodies of the most characteristic channel and mouth bar environments could be cut out from the porosity and sand content models. in this way not only their general geometry and internal characteristics, but also the basic geostatistical features (ratio of anisotropy, the direction of major and minor continuity) of their sand content and porosity were identifi ed. keywords: delta environment, 3d model, distributary channel, mouth bar sedimentological study of the szőreg-1 reservoir (algyő field, hungary): a combination of traditional and 3d sedimentological approaches � szilvia sebők szilágyi1 and jános geiger2 1 mol plc, hungary, exploration & production; (szszilagyine@mol.hu) 2 university of szeged, department of geology and paleontology, h-6722, szeged, egyetem u. 2., hungary; (matska@geo.u-szeged.hu) doi: 104154/gc.2012.06 geologia croatica 65/1 77–90 19 figs. zagreb 2012 geologia croaticageologia croatica 1. introduction the studied area is located in central europe, in the pannonian basin, south-east hungary. the algyő field is the largest hungarian hydrocarbon accumulation consisting of several oil and gas bearing reservoirs (fig. 1). a comprehensive description of the structural and geological setting of the fi eld is given in magyar et al. (2006). the upper members of these reservoirs have developed in a pannonian delta system due to complex lateral shifting and prograding phases. they can be subdivided into slope (algyő formation) and delta plain (újfalui formation) rock bodies. the sills of the individual reservoirs were formed during the delta abandonment phases. consequently, they can be accepted as time horizons in modelling studies. below these series, the lower reservoirs are regarded as turbidity rock bodies (szolnok formation) of partly prodelta fans and partly deep basin origin (révész, 1982). besides the evident economic importance, the rock bodies comprising the algyő field can be considered as an almost complete sequence of general pannonian (s. l) basin fi lling accumulation (bérczi & phillips, 1985; bérczi, 1988). here, according to the hungarian neogene geochronological terminology we use ‘pannonian (s. l)’ for late miocene-, pliocene sequences. in the algyő field, the pannongeologia croatica 65/1geologia croatica 78 ian delta progradation is one of the youngest within the great hungarian plain. on the basis of seismic data, vakarcs et al. (1994) then vakarcs (1997) published the fi rst results of mapping the shelf-margins of the prograding basin fi lling delta-systems. the most recent results have shown that self-margins reached the vicinity of the algyő filed about 5.7 million years ago (magyar, 2010, fig. 31). the szőreg-1 oil reservoir with a large gas cap is one of the largest sedimentary successions within the delta plain record (fig. 1). its average gross thickness is about 35 m, but locally it can reach 50 m. earlier work by révész (1982) and geiger et al. (1998) proved its delta plain origin with a signifi cant amount of fl uvial channel sedimentation. the main purposes of this study are to (1) provide a high resolution spatial-temporal description of the sedimentological evolution of the szőreg-1 reservoir rock body and (2) reveal the real (not simulated) 3d geometry of some depositional subenvironments characteristic of the delta-plain, using 3d contouring of quantitative well-log properties. basic aspects of the geo-cellular 3d modelling, methods of well-log calibration, multivariable classifi cations and interpretations of the grain size data have already been published (e.g. park, 1974; joreskog, 1976; geiger, 1986; geiger & werowski, 1992, molnár & geiger, 1995, geiger & komlósi, 1995, geiger, 2002; 2004). in this study we emphasize those aspects that can play a signifi cant role in the interpretation of new data. 2. rock types of szőreg-1 according to the well logs the internal heterogeneity of szőreg-1 is considerable (fig. 2). on the basis of sporadic cores, the following general picture can be compiled concerning the sedimentary rocks of the reservoir. the general succession starts with argillaceous marls, which can alternate with claystone, marl, and coaly argillaceous marl. their average effective porosity is about 0.07 (7%). argillaceous marls are also observed at higher stratigraphic positions, too, where they are interbedfigure 1: theoretical cross section of the algyő field. figure 2: geological cross section resulting from the 3d lithological model of the szőreg-1 reservoir. geologia croatica 79 sebők szilágyi and geiger: sedimentological study of the szőreg-1 reservoir (algyő field, hungary)... ded with lignite bands. in this latter situation, the vertical sequence of argillaceous marl, marl and lignite transitions are very characteristic. the thickness of the lignite bands or layers can vary from a few centimetres to tens of centimetres. foliation and shiny sliding surfaces are important features. this lower succession expresses abandonment processes of the previous delta lobes, as derived from the general sedimentological evolution of the algyő field (révész, 1982, geiger 2002, 2004). fine siltstones are grey – dark grey rocks showing foliation or earthy cracking. their average effective porosity is about 0.1 (10%). they contain a great amount of macrofauna, in some places even resembling lumashell too. this rock type is generally rich in coalifi ed plant fragments. fine siltstones show gradual coarsening upward (cu) transition toward coarse siltstones, but they can also be interbedded with thin fi ne sandstones. coarse siltstones are grey with frequently ochre discolouration. their average effective porosity is about 0.22 (22%). they contain quite high amounts of mica and fi ne sand. in general, coarse siltstones are laminated, picked out with coalifi ed plant fragments. fine sandstones are light grey, and similarly laminated to the coarse siltstones by coalifi ed plant fragments and mica. they usually represent gradual transitional stages between coarse sandstones and coarse siltstones. the average effective porosity is about 0.28 (28%). a yellowish gray colour characterizes coarse sandstones. they can also be laminated, but a massive, structureless development is also common. in some places, the clay mineral content of the pore space can be high, due to the presence of syngenetic clay and carbonate minerals. carbonate also occurs as carbonate grains. horizontal bedding, and high and low angle cross bedding/laminations are the most characteristic sedimentary structures. the average porosity is 0.30– 0.32 (30–32%). rock types, with the exception of the underlying argillaceous marl, do not form laterally continuous layers. they can be followed to only for tens or hundreds of metres. interfi ngering of the different rock types is a typical characteristic almost everywhere within the studied section (fig. 2). 3. methods a full-scale relational, sedimentological data base has been developed which includes qualitative and quantitative data about core analyses, horizontal layering, facies identifi cation, and well log interpretation. for macro sedimentological analysis it contains 382 grain size analyses from 53 wells, 291 routine petrophysical analyses from 356 wells, and 156 hg-capillarity measurements in 126 wells. geophysical logs and their quantitative petrophysical interpretations (at 0.2 m intervals) are available from 512 wells penetrating the whole reservoir thickness. they were used for mega-scale sedimentological analysis including study of well-log responses, and 3d modelling. 3.1. detailed core descriptions and facies identifi cations the focus was on genetic interpretations of the sedimentary structures and textures, in order to outline both the main depositional processes and the sedimentary facies together with some vertical core profi les. core descriptions played a signifi cant role in the identifi cation of depositional facies in three key-wells. descriptions are based on the system suggested by miall (1966, 1999). in identifi cation of depositional facies of the delta plain, and delta front succession, publications by reineck & singh (1973), galloway (1975), wright (1977), postama (1995) were useful, together with some recently published pliocene, pleistocene and holocene examples (e.g. hoogendoorn et al., 2005, longhitano, 2008; rohain et al., 2008, hoogen doorn et al., 2008) 3.2. multivariate statistical analyses (including qmode cluster and r-mode factor analysis) of the sporadic grain-size distributions according to some earlier works, the lateral variability of the transporting-depositing media can be taken into account by lateral extension of genetic groups determined via cluster analysis of grain-size distributions (park, 1974; geiger, 1986; geiger & werowski, 1992). for this purpose 382 grain-size distributions have been classifi ed using an r-hierarchical, q-type clustering technique. in this analysis the similarity coeffi cient was the cosine of the angle between any two vectors representing the samples. the method for reduction was the centroid approach (molnár & geiger, 1995). sedimentological interpretation of the resulting discrete groups and subgroups was carried out by the combined use of r-mode factor analysis (joreskog, 1976), and interpretation of the identifi ed sedimentary structures. the r-mode factor analysis was applied in a cluster-by-cluster manner to the grain size constituents, with the md and c value of samples belonging to a particular cluster (joreskog, 1976, molnár & geiger, 1995). 3.3. calibration of well log responses to cores with total core recovery in this phase we used the method introduced in hungary by révész (1980), where microlog, sp and gamma logs were used for calibration. the resulting “electrolithological units” were the tools used to extrapolate the rock types to the uncored regions. beside this feature, a semi-quantitative measure, the so-called sand-content (of 1m thick units), was derived from the types of electrolithologies (fig. 3, révész, 1980). this is the sandstone content (in percent) of the rock body with unit cross-sectional area and 1m thick (fig. 3). for instance, 80% sand content means that the 80% of the total rock volume can be expected to be sandstone, but it is not necessarily a continuous sandstone layer. this parameter can refl ect both the existence and the intensity of the palaeocurrents (révész, 1980). geologia croatica 65/1geologia croatica 80 3.4. 3d modelling approach and high resolution facies analysis the huge number of wells penetrating the reservoir facilitated the application of a special geo-cellular 3d modelling approach (geiger, 2002). quantitative geophysical interpretations were available at 0.2 m intervals in each well. applying any vertical interpolation in building 3d models would have smoothed out the small scale vertical variances which are needed for analysis by high resolution stratigraphy. the main goal was to emphasize the stratiform characteristics of the depositional systems within the reservoir thickness. the easiest method is to (1) cut the reservoir rock body by surfaces parallel with the bottom of the sill; (2) perform lateral parameter estimations on these surfaces; (3) build a 3d model by putting the grid systems of the second step below each other (fig. 4). if there is no considerable lateral erosion between the top and the bottom of the reservoir, these grid systems should honour the temporal evolution (houlding,1994). on each cutting surface, the data locations can be identifi ed by crossing the well trajectories and the cutting surfaces. between any two cutting surfaces, the petrophysical data (coming from well-log interpretations), of the 0.5 m thick vertical intervals were given by the average of the datum falling to these intervals. these average values were assigned to data locations on the cutting surfaces. the algorithm of lateral extension of porosity and sand content readings was the ordinary kriging with linear semi-variogram model. the resulting grid systems can be used in two different ways. on each cutting surface, the grid systems are of the same size. the easting and northing coordinates of each grid node are known. the distance of each nodal point from the topmost surface is also known. this distance is uniformly 0 m on the fi rst cutting surface, 0.5 m on the second one, etc. note, that in this way we applied the so called stratigraphical coordinate system introduced by deutsch (2002). in addition, certain petrophysical values (from the lateral extensions) are also assigned to each grid node. so, there is everything at hand to visualize a geo-cellular 3d model of the rock body (houlding, 1994). this is a trivial application of the grid systems. the grids defi ned in a vertical sequence, however, can play a signifi cant role in the high resolution facies analysis of the key wells, as well. in these wells the depositional facies of the reservoir section are known. that is, at the crossing of a key well trajectory and a particular cutting surface, the depositional facies is already known from the previous steps. the task is to figure 3: electrolithological types and their sand contents defi ned by micrologs and cores with total core recovery (after révész, 1980). figure 4: 3d geo-cellular modelling process (after geiger, 2002). geologia croatica 81 sebők szilágyi and geiger: sedimentological study of the szőreg-1 reservoir (algyő field, hungary)... fi nd that particular sand contour on this surface which coincides with the geometry of the depositional facies identifi ed (fig. 5). in this way, after drawing the results of facies analysis on the maps, the boundaries of the different depositional environments can be defi ned by sand isopachs. this method is called high resolution facies analysis, since it gives the 3d geometry of any depositional environment with 0.5 m of vertical resolution (geiger & komlosi, 1996, geiger, 2002). this approach has two constraints. firstly, the topmost surface of this sectioning process should be a time horizon. secondly, there must not be any tectonic movements, the effects of which are laterally variable. the sill of the szőreg-1 reservoir was formed during a delta abandonment phase. therefore it can be considered as a time horizon in modelling studies. moreover, at the time of deposition, the top argillaceous marl can be regarded as a quasi-horizontal surface. the seismic interpretations have proven that within the geological time frame of the szőreg-1 reservoir there were no lateral tectonic movements. so these stacked maps/grids will refl ect the depositional history in the time interval of the accumulation of the szőreg-1 reservoir. 4. results 4.1. sedimentary structures in both the sandstone and coarse siltstone series, the most frequent bedding form is horizontal planar lamination (fig. 6, a). in coarse siltstones it represents undisturbed sedimentation following stokes’ law, but in sandstones it can be interpreted as a planar bedding in an upper fl ow regime. the latter proves the existence of strong sand laden currents. characteristically, the planar beds of the upper fl ow regime are associated with trough cross bedding (fig. 6, b). this feature may express channel progradation, which is a natural phenomenon in the course of delta accumulation both in mouth bar evolution, and crevassing. fine siltstone and argillaceous marl series often have small sand lenses which can be derived from temporary sandy accumulation from weak currents within interdistributary bays (fig. 6, c). fine siltstones and argillaceous marls exhibit characteristic bioturbation. load structures and convolutions in the figure 6: characteristic sedimentary structures from the szőreg-1 reservoir. figure 5: high resolution facies analysis (after geiger & komlosi, 1996; geiger, 2002). geologia croatica 65/1geologia croatica 82 form of soft sediment deformation are also very frequent (fig. 6, d). 4.2. statistical analysis of grain size distributions the sedimentological interpretations of the discrete groups and subgroups were carried out by combined use of r-mode factor analysis and the interpretation of the identifi ed sedimentary structures. the r-mode factor analysis has been applied in a cluster-by-cluster manner for the grain size constituents, and the md and c value of grain size distri butions. as a result the samples could be subdivided into two main groups. they are sandy coarse siltstones and fi necoarse grained sandstones (fig. 7). the sand:silt ratio of samples belonging to the fi rst group is about 1. in this group, beside the fi ner parts of active channels, interdistributary bays and crevasse splays, the sediments of distributary channels were also identifi able (fig. 7). the second group (fi ne-coarse sandstones) represents the coarse material deposited as channel-lag of the active distributaries and the coarser grained sediments of distributary mouth bars (fig. 7). to study the relationship between grain size distribution and sedimentary facies, the core survey data were genetically divided into fi ve subfacies and 1 transitional subfacies. these include (1) natural levee and channel complexes, (2) distributary channels, (3) crevasse splays, (4) prograding crevasse splays, (5) deposits of swamp and channel abandonments, (6) crevasse and abandonment as a transitional subfacies their averaged cumulative grain size distribution curves are shown in fig. 8. figure 7: results of the multivariate analysis of grain si ze distributions. figure 8: averaged grain size distributions by depositional facies. geologia croatica 83 sebők szilágyi and geiger: sedimentological study of the szőreg-1 reservoir (algyő field, hungary)... the swamp-channel abandonments are the most heterogeneous in the light of grain size distribution. more than 50 % of the sediments are composed of grains smaller than 0.02 mm (fi ne silt and fi ner sediments). sediments with grain-size diameters greater than 0.1 mm are subordinate (fig. 8). crevasse splays are composed of a mixture of grain sizes from two origins. they represent distributary channels, and the remains of natural levees that were occasionally eroded. these sediments were deposited under high transportation energy of fl ood events. the presence of a coarse grain size and the relatively weak sorting also refl ects these processes in the cumulative grain size distribution. the recurrence of the processes characterized above, can result in the progradation of crevasse splays. the outcome of these events is a slightly better sorting texture than that of distributary channels. more, than 50 % of the grains are between 0.1–0.3 mm. this population may have originated from two or three sources: (1) reworked and redeposited material of former crevasse splays, (2) the results of channelization or avulsion, and (3) sediments of natural levees. it has the coarsest grains, which is the result of the higher transporting energy. in contrast, sediments of prograding crevasse splays are the most well sorted, and have the most sloping grain size curves. the frequency of grains smaller than 0.01 mm is around 10 % (fig. 8). the average cumulative grain size distribution of the distributary channels is similar to that of prograding crevasse splays, but the coarsest grain size is slightly smaller. they are well sorted, with a modal grain-size of fi ne sand, where 40 % of the grains are between 0.1–0.2 mm (fig. 8). the natural levee – channel complexes are characterized as a transitional subfacies. the shape of the individual, not averaged, curves can be informative in determining whether it results from an early or late channelizing state of natural levees. the greatest grain size and the modal grain size class are affected by the greatest and the average energy of sediment transport. based on the cumulative grain size diagrams of the studied subfacies, the following succession can be established according to decreasing fl ow velocity: (1) prograding crevasse splays, (2) crevasse channels incised to the deposits of crevasse splays, (3) crevasse splays, (4) natural leveechannel complexes, (5) deposits of late crevassing and abandonment processes, (6) deposits of swamp and channel abandonments (fig. 8). 4.3. depositional facies the identifi cation of depositional facies resulted from hydrodynamic interpretations of sedimentary structures and grain size distributions. lateral extension of facies away from the vertical columns determined in the wells is demonstrated by the maps of the corresponding mapping surfaces. 4.3.1. minor mouth bar – channel transition this transition can be detected in different stratigraphic positions within the reservoir. it can develop when a linear fl ow figure 9: vertical transition of a mouth bar and channel facies. figure 10: vertical transitions of a crevasse splay and channel facies. geologia croatica 65/1geologia croatica 84 enters a still water bay. in this situation the sediments of the prograding fl ow are initially coarse siltstones (fig. 9, a) which are followed by gradually coarsening sandstones (fig. 9, b). on figs. 9a & b, the still water sedimentation, and geometry of the outer bar can clearly be identifi ed. later, in front of the channel head, a bar-crest develops as the result of channel and basin interactions. during this process the accumulation progrades toward the basin or bay. on fig. 9c, this minor mouth bar appears as a characteristic kidneyshaped geometry. the mouth-crest with high sand content can also be identifi ed. in the next phase the distributary channel cuts to the body of the minor mouth bar. 4.3.2. crevasse splay – crevasse channel – minor mouth bar transition one of the typical examples of crevasse splays is shown on fig. 10a. the upper part of the core may be identifi ed as a vertical section of a mouth bar. the lateral extension of this facies represents a small channel ‘breaking out’ from the minor bar with a nw–se depositional strike (fig. 10, c). 4.3.3. minor mouth bar facies in some situations the bar facies appears as a ‘stand-alone’ succession, as in fig. 11. in addition to the prograding sequence, (upward coarsening grain size tendency), the geometry also shows how bar crest development follows outer bar sedimentation. 4.4. sand isopach and facies distribution maps the modelling process of the rock body was extended to 45 m below the permeable top. this volume was sectioned by surfaces being parallel to the top. the vertical distance between any two surfaces was 0.5 m. their lateral resolution was 100 x 100 metres. the following development can be summarized for the rock body from these maps. from 40 to 45 m below the top the sedimentological evolution is characterized by quite a large distributary mouth bar developed at the south-western rim of the reservoir (fig. 12, a). the area of this mouth bar is about 14 km2, its thickness is about 5 metres. this rock body gradually prograded into a shallow, quiet water bay (fig. 12, a). later the focal point of the bay-fi lling accumulation shifted to the north–west in the form of a distributary channel. this channel is fl anked by crevasse splays of different sizes (fig. 12, b). its length is about 10–12 km, the average width is 200–300 metres, its thickness is 1–3 metres. this shallow, long channel form is quite characteristic of the recent distributary channels. figure 11: vertical development of a distributary mouth bar facies. figure 12: sand isopach maps on cutting surfaces. geologia croatica 85 sebők szilágyi and geiger: sedimentological study of the szőreg-1 reservoir (algyő field, hungary)... within the interval of 19–29 m below the top, the depositional system is characterized by wider lateral extension of a sandy rock body with > 90% sand content. the equivalent sedimentary rocks are coarse and medium grained sandstones. at that time the focal point of the main depositional processes was in a zone of ne–sw depositional strike (fig. 12, c & d). the main depositional environments were bifurcating channels and small distributary mouth bars in front of them (fig. 12, c and d). the length of the largest bifurcating channel is about 1.5 km, its width is around 200 metres, and the average depth is about 2–3 metres. sheet like sandstone rock bodies were developed by laterally merging (minor) mouth bars. at this time fi ne siltstone and argillaceous marl sedimentation characterizes the nw and se regions of the reservoir. within the central regions, the largest extent of sand can be detected between 10 and 19 m below the top (fig. 12, e). from 7 to 10 metres below the top these sandstone bodies are disintegrated (fig. 12, e) and the main depositional system shifted to the nw part. later in this region, a continuous sandy sheet developed while in the se foreland the accumulation of siltstones, argillaceous marls and subordinate silty sandstones continued (fig. 12, g and h). these different identifi ed sandstone bodies represent one hydrodynamic system forming one particular reservoir. 4.5. general characterization of the 3d geometry, porosity and sand content of the signifi cant depositional environments as outlined above, one of the most important controls on the whole depositional history is a large distributary channel with sw–ne depositional strike (fig. 13 a, b). this can be studied between 24–27 m below the top of the reservoir. based on the 3d representation, it reaches a maximum of 5–6 km in length and about 2–400 m width. the average thickness is 2–2.5 m. the 3d form of this channel partly refl ects its progradation from the sw to the ne, and partly crevassing from the main channel (fig. 13 a, b). the highest sand content can be seen along the axis of the channel. the lateral and vertical distributions of its porosity and sand content are similar to each other. it is also very characteristic, that the largest porosity values belong to the upper part of the channel (fig. 13, b). figure 13: 3d geometry and sand content of a large, bifurcating channel. figure 14: temporal evolution of a channel system represented in fig.13 geologia croatica 65/1geologia croatica 86 the progradation of this channel system is demonstrated in fig. 14, a–d. in addition to the dendroid channel geometry, it can also be seen that after a progradation phase, during the still-stand period, a mouth bar type geometry with high sand content developed at the hinterland the channel (fig. 13, b). it suggests the following lateral transitions of the depositional processes: (1) channel progradation, (2) mouth bar evolution, (3) new channel progradation by breaking out from the mouth bar. this sequence is in harmony with the interpretation of both trough cross-bedding and horizontal planar laminations of the core samples coming from a channel environment. the frequency distributions of the vertically averaged nodal sand content and porosity values in the thickness of the channel system show poly-modal histograms (fig. 15 a and b) with 80.5 %, and 25.5% averages for sand content and porosity respectively. we have performed variography analysis of both average sand content and porosity grids. the results are shown in fig. 15c and d. the lateral continuity of average sand content is quite high, since the gaussiantype variogram function gave the best model-result. the main continuity direction of sand content is comparable to the depositional strike of this rock body (fig. 14, fig. 15, e). the range in this direction is about 471 m, in the perpendicular direction it is around 339 m. the calculated ratio of anisotropy is 0.72 (fig. 15, e). since the nugget effect is low, just one-tenth of the sill, this model can characterize almost 90% of the total variance in the terms of linear geostatistics. figure 15: statistical and geostatistical characters of sand content and porosity grids of the channel shown in figs.13 and 14. signs and abbreviations in parts a and b: sd = standard deviation. geologia croatica 87 sebők szilágyi and geiger: sedimentological study of the szőreg-1 reservoir (algyő field, hungary)... in the case of the averaged porosity grid, the main continuity direction is much the same as that of the sand content (fig. 15, e, f). in practice, this suggests that the textural anisotropy may either impact on, or determine the spatial variance and continuity of porosity. the similarity of anisotropy ratios (0.72 for sand content and 0.81 for porosity) supports this conclusion (fig. 15, f). the next main physiographic units are the distributary mouth bars. among them the larger, south-western one, observable between 34 and 39 m below the reservoir top, signifi cantly affected the initial accumulation phase (fig. 16, a). based on the 3d geometric representation (fig. 16, b, c), its planar area is about 14 km2, the thickness is around 5 m. the 3d sand content distribution demonstrates an upward coarsening trend. the highest sand content can be seen on its top showing that the background channel cut itself into the bar crest (fig. 16, b). the spatial distribution of porosity does not follow the spatial variation of sand content as close as well as in the case of channel system (fig. 16, c), although the upward increasing effective porosity is typical. fig. 17 (a to f) demonstrates its temporal evolution. the characteristic kidney-shaped geometry can be clearly recognized on each map. on fig. 17 (c to f), even the bar crest with the highest sand content can also be identifi ed. at the left and right wings of the bar, the development of subaqueous natural levees refl ects the initial stage of channel cutting and prograding processes (fig. 17, c). the disturbance of sand contours at the ne border of the bar may represent sliding and slumping deformation being frequent within the distal/outer bar region (fig. 17, d). the frequency distributions of vertically averaged sand content and porosity values exhibit good homogeneity in the case of sand content and poly-modality for the porosity. the average sand content of this bar is 53.7%, the average porosity is 19.23%, though the most characteristic porosity values are around 22.4% (fig. 18, a, b). the lateral continuity of the sand content is also stronger than that of the porosity (fig. 18, c, d), since a gaussian model seemed to be the most appropriate for modelling the semivariance of sand content. in the case of porosity, the semivariogram model was an exponential one. for both properties the main continuity directions coincide with the long axis of the bar crest being perpendicular to the direction of bar progradation. the anisotropy ratios are the same figure 16: 3d geometry and sand content of a mouth bar. please note: (1) for better visualization the ‘b’ and ‘c’ parts are rotated; (2) although ‘a’, ‘b’ and ‘c’ show the same mouth bar, the ‘b’ and ‘c’ parts are rotated. figure 17: temporal evolution of a mouth bar represented in fig.16. geologia croatica 65/1geologia croatica 88 (0.78) for both sand content and porosity, (fig. 18, e, f). therefore it suggests that the lateral continuity of textural characters had a signifi cant effect on the spatial characters of effective porosity. the 3d sand content model of the szőreg-1 reservoir indicates that a type of sheet sand drape was developed by lateral merging of the “border” mouth bars. 5. discussion on the depositional history of the szőreg-1 reservoir as a summary, at least three main depositional processes should be taken into account in the evaluation of the depositional history based on traditional sedimentological analysis of the core samples, well-log responses, and the 3d modelling of sand and porosity content. they are the followings: (1) development of a mouth bar in the south-western part and a large distributary channel breaking out from this body; (2) development of a mouth bar in the opposite direction; (3) progradation of a large distributary channel from the nw to the se. high resolution analysis has revealed that there were several transport directions from the ‘borders’ to the central parts in the evolution of this rock body. this analysis also highlighted the scale of the most detectable depositional environments. the data and their interpretations have shown that most of the channels were short and several metres in thicknesses. although the identifi ed mouth bar is relatively figure 18: statistical and geostatistical characters of sand content and porosity grids of the mouth bar shown on figs.16 and 17. signs and abbreviations in parts a and b: sd = standard deviation. geologia croatica 89 sebők szilágyi and geiger: sedimentological study of the szőreg-1 reservoir (algyő field, hungary)... as a consequence, the above mechanism resulted in the infi lling of an interdistributary bay mimics larger delta sedimentation. the main difference is obviously the scale and the fact that the driving force, in the accumulation of szőreg -1, was a multiple source crevassing process and the main delta channels were outside of the study area. according to the depositional strikes they must have been at the sw and ne wing of the algyő field. 3d characterization of the revealed channel and minor mouth bar environments also suggests a particular depositional environment where the coincidence of lateral continuity measurements (ratio of anisotropy and the main continuity direction) of sand content and porosity, shows that depositional processes have left a signifi cant fi ngerprint on the lateral distributions of porosity. it is important to remember that these properties have been determined independently, since the sand content came from qualitative and porosity from quantitative well log interpretations. one of the most trivial interpretations of this result is that the defi nition of fl ow units in a dynamic reservoir simulation should rely on the correlation of those steps of sedimentological history which were outlined in section 4.5. acknowledgement the authors would like to express their acknowledgement to the hungarian oil and gas company (mol group) for permission to publish these results. also, many thanks for the two reviewers for their valuable suggestions and comments. references bérczi, i. & phillips, r.l.(1985): processes and depositional environments within neogene deltaic-lacustrine sediments, pannonian basin, southeast hungary.– eötvös lóránd geophysical institute, geophysical transactions, 31/1–3, 55–74. bérczi, i. (1988): preliminary sedimentological investigations of a neogene depression in the great hungarian plain.– in: royden, l.h. & horváth, f. (eds): the pannonia basin: a study in basin evolution. aapg memoir, 45, 107–116. coleman, j.m., cagliano, s.m. & webb, j.e. (1964): minor sedimentary structures in a prograding distributary.– mar. geol., 1, 240–258. elliott, t. (1978): deltas.– in: reading, h.g. (ed): sedimentary environments and facies. blackwell scientifi c publications, 105–107. galloway, w.e. (1975): process framework for describing the morphologic and stratigraphic evolution of deltaic depositional systems.– in: broussard, m.l. (ed.): deltas, models of exploration. houston geological society, 87–98. geiger, j. (1986): üledékes homokkőtestek szöveti és morfogenetikai vizsgálata [textural and morphogenetic study of sedimentary sandstone bodies – in hungarian].– földtani közlöny, 116/3, 249–266. geiger, j. (2002): a pannóniai újfalui (törteli) formációban levő algyő-delta fejlődéstörténete: i. az algyő-delta alkörnyezeteinek 3d modellezése [depositional history of algyő-delta (újfalui (törteli) formation: 3d modelling of the subfacies of algyő-delta – in hungarian].– földtani közlöny, 133/1, 91–112. geiger, j., kissné, v.k. & komlósi, j. (1998): a szőreg-1 telep 3d rezervoár geológiai modellje [3d reservoir geological modell of szőreg-1 reservoir – in hungarian].– open-fi le report of mol engineering offi ce of research and development, #156-5636, 216 p. large in its planar area, the recognized thickness is not larger than 5 metres. these scales are not comparable with those of well-developed delta systems which may act in the pannonian accumulation of the great hungarian plain. the evidence, however, shows a real delta succession. this contradiction can be solved by supposing that this rock body is the result of processes infi lling a larger interdistributary bay. some well documented recent examples (e.g. coloman et al., 1964, elliott, 1978) have shown that in these cases crevassing is the main driving mechanism in the accumulation of interdistributary bays. in this situation, the stabilized crevasse channels with minor mouth bars developed in front of them, can act as delta lobes. the infi lling process is achieved by their lateral accretion (elliott, 1978 p. 107). according to our results it can be concluded, that quite a large amount of interdistributary bay sedimentation should be taken into account within the study area (fig. 19, a). during the initial stage, the sandy accumulation concentrated in the sw part, where the appearance of one larger and several smaller distributary mouth bars expressed the preliminary lobe-prograding period (fig. 19, b). later these discrete mouth bar bodies merged and a laterally extended sheet-like sand body was formed within the sw region (fig. 19, c). as a background main channel or delta lobe become more active, new higher energy distributaries cut down into this sheet (fig. 19, d). by their lateral migration a new generation of sheet-like sand bodies form and progrades toward the deeper parts of the bay. in front of the channels, new mouth bars develop and merge, meanwhile in the hinterland a typical fl uvial deposition dominates (fig. 19, e). figure 19: depositional history of the szőreg-1 reservoir. geologia croatica 65/1geologia croatica 90 geiger, j. & komlósi, j. (1995): 3-d geological simulation of a deltaic reservoir in hungary.– aapg congress, 1995, nice, proceedings, 65–80. geiger, j. & komlósi, j. (1996): szedimentológiai, geomatematikai 3-d modellező rendszer törmelékes ch-tárolókban [sedimentological, geomathematical modelling system in clastic reservoirs – in hungarian].– kőolaj és földgáz, 2, 53–81. geiger, j. & werowski, p.v. (1992): geomathematical modelling of a turbiditic reservoir in se. hungary.– in: amilcar soares (ed.): geostatistics troia’92, 1, 311–323, kluwer academic publishers, dordrecht–boston–london. hoogendoorn, r.m., boels, j.f., kroonenberg, s.b., simmons, m.d., aliyeva, e., babazadeh, a.d., & huseynov, d. (2005): development of the kura delta, azerbaijan: a record of holocene caspian sea-level changes.– mar. geol., 222/223, 359–380. doi:10.1016/j.margeo.2005.06.007 hoogendoorn, r.m., overeem, i. & storms, j.e.a. (2008): process-response modelling of fl uvio-deltaic stratigraphy.– comput. geosci., 34, 1394–1416. doi:10.1016/j.cageo.2008.02.006 joreskog, k.g. (1975): geological factor analysis (methods in geomathematics, vol. 1).– elsevier, 190 p. longhitano, s.g. (2008): sedimentary facies and sequence stratigraphy of coarse-grained gilbert-type deltas within the pliocene thrust-top potenza basin (southern apennines, italy).– sediment. geol., 210, 87–110. doi:10.1016/j.sedgeo.2008.07.004 magyar, i. (2010): a pannon medence ősföldrajza és környezeti viszonyai a késő miocénben [paleogeographical and paleoenvironmentological characters of the pannonian basin in the late miocene – in hungarian].– geolitera, szeged, 140 p. magyar, i., fogarasi, a., vakarcs, g., bukó, l. & tari, c., g. (2006): the largest hydrocarbon fi eld discovered to date in hungary: algyo.– in: golonka, j. & picha, f.j. (eds.): the carpathians and their foreland: geology and hydrocarbon resources. aapg memoir, 84, 619–632 p. miall, a.d. (1966): the geology of fl uvial deposits.– springer, 582 p. miall, a.d. (1999): in defense of facies classifi cations and models.– j. sediment. res., 69/1, 2–5. molnár, b. & geiger, j. (1995): possibility for subdividing apparently homogeneous depositional sequences by combined use of sedimentological, paleontological and mathemathical methods.– geojournal., 36, 2/3, 169–177. postma, g. (1995): causes of architectural variations in deltas.– in: oti, m.n. & postma, g. (eds.): geology of deltas. balkema, rotterdam, 3–16. reineck, h.e. & singh, i.b. (1973): depositional sedimentary environments.– springer verlag, new york, 103–142. révész, i. (1980): az algyő-2 telep földtani felépítése, üledékföldtani heterogenitása és ősföldrajzi viszonyai [hydrocarbon deposits algyő -2: geological structure, sedimentological heterogeneity and paleogeographic features – in hungarian].– földtani közlöny, 110, 512–539. rohais, s., eschard, r. & guillocheau, f. (2008): depositional model and stratigraphic architecture of rift climax gilberttype fan deltas (gulf of corinth, greece).– sediment. geol., 210, 132–145. doi:10.1016/j.sedgeo.2008.08.001 vakarcs, g., vail, p.r., tari, g., pogácsás, gy., mattick, r.e., & szabó, a. (1994): third-order middle miocene-early pliocene depositional sequences in the prograding delta complex of the pannonian basin.– tectonophysics, 240, 81–106. vakarcs, g. (1997): sequence stratigraphy of the cenozoic pannonian basin, hungary.– unpubl. phd thesis, rice university, houston, texas, 514 p. wright, l.d. (1977): sediment transport and deposition at river mouths: a synthesis.– geological society of america bulletin, 88, 43–53. manuscript received june 26, 2011 revised manuscript accepted december 12, 2011 available online february 25, 2012 zecevic.indd 225 � ab stra ct discovery of petroleum source rocks at surface exposures of the badenian deposits on the northern slopes of krn dija mt. is the fi rst record of petroleum source rocks at outcrop in the croatian part of the pannonnian basin. rocks with increased organic matter content have the characteristics of prime source rocks. positive hydrocarbon potential is the consequence of a favourable type of organic facies. type ii kerogen is of mostly marine algal origin, but with somewhat more pronounced terrigenic lipid content. source rocks are in the immature, diagenetic period of thermal transformation. genesis of these rocks is related to the reducing depositional environment in a mostly shallow sea, formed in protected lagoons during the badenian period, which was reconstructed using palaeogeomorphological, palaeontological, petrographical and organogeochemical analyses. these new petrological data deserve attention as they highlight the need for additional geological-geophysical-geochemical research of the petroleum potential of the badenian deposits in the broad area around našice. keywords: petroleum geology, source rocks, badenian, krndija mt., croatia, pannonian basin signifi cance of the badenian petroleum source rocks from krndija mt. (pannonian basin, croatia) � marko zečević1, josipa velić2, jasenka sremac3, tamara troskot-čorbić4 and vesnica garašić2 1 ministry of defense, republic of croatia, trg kralja petra krešimira iv, hr-10 000 zagreb, croatia; (mzecevic@morh.hr) 2 faculty of mining geology and petroleum engineering, university of zagreb, pierottijeva 6, hr-10 000 zagreb, croatia; (josipa.velic@rgn.hr; vesnica.garasic@rgn.hr) 3 faculty of science, university of zagreb, horvatovac 102 a, hr-10 000 zagreb, croatia; (jsremac@yahoo.com) 4 ina oil industry, lovinčićeva b.b., hr-10 000 zagreb, croatia; (tamara.troskot-corbic@ina.hr) doi: 104154/gc.2010.19 geologia croatica 63/2 225–239 13 figs. 3 tabs. zagreb 2010 geologia croaticageologia croatica 1. introduction according to bioproduction in the sea and on land, the area covered, and the volume of material deposited, the badenian sediments have a signifi cant petrological potential which has not been suffi ciently explored either using boreholes or at outcrops. these outcrops on the edges of mountain massifs, used to form the edges of pools or islands in the badenian sea. badenian sediments, which have a thickness of no more than a few dozen metres in the outcrops of the slavonian mountains, can attain thicknesses of several hundred metres in deeper areas of sedimentary basins. palaeorelief, or more precisely a rugged coastline with numerous lagoons and bays, provided excellent conditions for the accumulation of organic matter in anaerobic conditions necessary to create kerogen. therefore, the conclusions of hernitz et al. (1995) are very indicative, in this respect and contain a detailed analysis of source rocks in the area between našice and donji miholjac. the analyzed rocks are mostly badenian in age, with a few older sediments, which contain source rocks of 500–600 m thickness. geologia croatica 63/2geologia croatica 226 the aforementioned data have facilitated creation of a synthetic column, used to correlate the badenian sediments from “bukova glava”, with the seismic sections and badenian sediments defi ned in certain intervals of the nearest wells in the drava depression. they were also used for construction of an isopach map (contour map of true thickness) of the badenian sediments in the broad area around našice. surface and sub-surface regional petrological research into the age and facies of core rocks in the croatian part of the pannonian basin, has been undertaken and published by numerous authors including; kranjec et al. (1976), hernitz (1983), prelogović et al. (1998), hernitz et al. (1993), velić et al. (2000, 2002,), lučić et al. (2001), pavelić (2001) and pavelić et al. (2003a, 2003b). more recently, there is the work of saftić et al. (2003), and vrsaljko (2007), while malvić (2006) published in the fi eld of geostatistics. deposits of neogene age were distinguished in three sedimentary megacycles of the 3rd order, composed of sequences of well defi ned lithological units in the rank of formations (velić et al., 2002), (fig. 3). the fi rst and oldest megacycle, of diverse and varied lithological composition, belongs to the lower and middle miocene. it contains petroleum source fi ne-grained clastics and occurs in some of the largest petroleum reservoirs discovered in croatia such as beničanci and molve. the second upper miocene megacycle is specifi c by the even alternation of sandstone and marl fi gu re 1: geographical location of the republic of croatia, showing the broad area with the position of the research area and a geological map of krndija mt. (croatian geological survey, 2009). legend: metamorphic rocks, precambrian; 2. clastic deposits, upper permian; 3. clastic deposits and carbonates with clastics, ottnangian, karpatian; 4. magmatic rocks: andesites and rhyolites, karpatian and badenian; 5. lithothamnion limestone and clastic deposits with volcanic rocks, badenian; 6. carbonate-clastic deposits, sarmatian and panonnian; 7. clastic deposits with coal, pontian; 8. sands and clays, miocene and pliocene; 9. paludina deposits, dacian and romanian; 10. clastic deposits, pliocene-pleistocene; 11. loess, pleistocene; 12. diluvial-proluvial deposits, holocene; 13. alluvial deposits, holocene; 14. fault; 15. thrust; 16. normal fault; 17. erosional or erosional-tectonicaly boundary; 18. location of the studied area. for a complete reconstruction of petrological relationships, research on surface outcrops is necessary, as well as full depth geological research which would encompass not only the badenian sediments but also the upper parts of the karpatian and lower parts of the sarmatian (including the karpatian/badenian and badenian/sarmatian boundaries). on the trail of such ideas, full research was conducted on the easily accessible badenian sediments at “bukova glava” near našice, on the northern slopes of mt. krndija (fig. 1). a comprehensive analysis and reinterpretation of data provided by the croatian national petroleum company “ina oil industry” from the nearest research boreholes as well as seismic sections of the drava depression has also been performed. on the northern slopes of mt. krndija, at the site of “bukova glava” (fig. 2) stratimetric scans and rock sampling were conducted, in order to ascertain their petrological signifi cance, i.e. determine their caprock properties, reservoir properties and the presence of source rocks. with this goal in mind, samples were collected and used for organogeochemical research as well as samples for determining permeability and porosity. palaeontological research served to reconstruct palaeoecological conditions and biostratigraphic subdivision, and data were collected for reconstruction of several geological columns and profi les. furthermore, samples used to determine the mineral and chemical content were collected from several layers, and on the “gradac” notch, samples of the “basement rocks”, or rocks from the preneogene base were also gathered. zečević et al.: signifi cance of the badenian petroleum source rocks from krndija mt. (pannonian basin, croatia) geologia croatica 227 pliocene marls, sandstones, gravels, clays and coal. they are overlain by the so-called “quaternary cover” composed of gravels, sands, dust, clays and loess. 2. materials, data and methods of research detailed analysis in the fi eld, and scans of geological columns, has yielded rock samples selected for mineralogical, petrographic, geochemical and organogeochemical analyses. three detailed geological columns have been recorded in the quarry near našice that produces raw material for cement with all transitional varieties. many sandstone petroleum reservoirs are located here, of which the ones in the fi elds of stružec, žutica, ivanić-grad and kloštar ivanić are the largest. the third megacycle is of pliocene-quaternary age, and is composed of sand, clay, gravel, and sporadically lignite/ tuff. it is currently thought to be of negligible petroleum signifi cance. neogene sediments transgressively overlie the palaeozoic “basement” of krndija mountain in line with the development of the croatian part of the pannonian basin system. these are miocene breccias, conglomerates, sandstones, limestones, volcanics, tuffs, tuffi tes, marls and coal, and fi gu re 2: a photograph of the “bukova glava” exploitation area. fi gu re 3: stratigraphic classifi cation for the range of tethys and paratethys with e-log markers and percentages of oil exploratory wells in the croatian part of the pannonian basin as well as marked environments of sedimentation and megacycles (updated after steininger et al., 1988; velić et al., 2002; hernitz et al., 2002). geologia croatica 63/2geologia croatica 228 production. on the basis of this data and the data collected from shallow boreholes (drilled to estimate reserves of raw cement material), a detailed synthetic geological column has been reconstructed. 2.1. palaeontological methods of determining fossil samples samples with macrofossils were isolated in the fi eld, and later refi ned and prepared for determination. samples for micropalaeontological analysis were taken from layers with visible lithological change. in total, 42 samples of approximately 0.5 kg were taken. in the base of the column, where potential petroleum source rocks were perceived in the fi eld, 15 samples were collected at approximately 30 cm intervals. in order to determine the fossil fl ora and fauna, the following papers were consulted: hörnes (1856), gorjanovićkramberger (1891), agip s. p. a. (1982), papp & schmid (1985), cimerman & langer (1991), hottinger et al. (1993), rögl & brandstätter (1993), harzhauser et al. (2003), mandić (2004), wesselingh (2006). fi gu re 4: synthetic column with the overview of lithological and fossil composition and textural properties. legend: biocalcarenite and argillaceous marl in alternation; 2. biocalcarenite and biocalcrudite; 3. algal massive limestone; 4. marly limestone; 5. algal-gastropodbryozoan limestone; 6. grey limestone and marl in alternation; 7. grey marly limestone; 8. mylonite, product of deformation of granite or gneiss, micaschist; 9. benthic foraminifera; 10. benthic ostracods; 11. planktonic foraminifera; 12. land fl ora; 13. macoma; 14. arca; 15. lithothamnium; 16. gastropods; 17. amussium; 18. pecten/ chlamys; 19. corbula; 20. cera stoderma; 21. schizasteridae; 22. isocardia; 23. fish; 24. bryozoans; 25. serpulids; 26. parallel lamination; 27. bioturbation; 28. erosional surface. zečević et al.: signifi cance of the badenian petroleum source rocks from krndija mt. (pannonian basin, croatia) geologia croatica 229 2.2. petrological analyses three samples were prepared for macroscopic and microscopic petrological analyses (ptc1, ptc2 i sc1). samples ptc1 and ptc2 were collected from the cement quarry “tajnovac” and the exploitation area “bukova glava”, on the požega–našice road, for the purpose of determining the presence of basement rocks. sample ptc1 was taken 11 kilometres away from the road, and ptc2 7.5 kilometres from the entrance to the quarry (ptc2 is approximately 4 kilometres in a straight line distance from the top of “bukova glava”). the locations where both samples were collected are on outcrops by the road below the “lončarski vis” peak (492 m), in the immediate vicinity of the “gradac” crossing (355 m). sample sc1 was taken from the lowest part of the synthetic column, therefore from the oldest available part of the badenian sediments (fig. 4). 2.3. methods for determining permeability and porosity to determine permeability and porosity, six samples were collected from selected locations. petrophysical testing was performed in the sector for research and development, service for evaluation of rocks and reservoir fl uids of ina-oil industry. two samples had distinct bedding and were sampled both parallel and perpendicular to the bedding plane. from six samples a total of eight cylinders were crafted – fi ve of them 3.84 cm (1½ inch) in diameter and three 2.56 (1 inch) in diameter. prior to determination of permeability and porosity, the samples were dried at 105°c. porosity is determined using a volumetric method in a gas porosity meter crafted by the corelab company using nitrogen to fi ll the empty porous space. this method is based on the expansion of gas from the reference cell to the cell of known volume containing the sample. the pressure drop is equivalent to the volume of solid phases. measurement is based on boyle’s law of gas expansion. permeability is determined in a gas permeameter by measuring the pressure drop during the fl ow of nitrogen through the sample. measurement is based on darcy’s law of fl uid fl ow through a porous medium in terms of laminar fl ow. the standard method uses pressure tightening the sample at 12 bars. the results are then corrected for the klinkenberger effect. the permeability and porosity results are as shown in table 1. 2.4. organogeochemical methods five chosen samples were analyzed using organogeochemical analysis. preparation of samples included: washing, drying, grinding in a fritsch mill and fi ltering through a screen to a particle size of 315 μm. the total amount of carbon was determined on a leco ir 212 carbon determinator. by determining carbon the sample was pre-processed with 18% hot chloride acid in order to remove carbonate material. the ground rock particles were then analyzed on a rock-eval 6 pyrolizer (espitalie et al., 1985). on the basis of the parameters obtained by rock-eval pyrolisis (toc, s1,s2, s3, tmax, hi, oi, pi) diagrams were produced which offer insight into the richness, generative potential, quality (type of kerogen) and maturity of organic matter. isolating organic matter (kerogen) for optical testing, determination of the sulphur content and stable carbon isotopes, was done by standard chemical-physical methods of inorganic component breakdown using hcl and hf acids, and separating heavy metals by a zncl2 solution with a density higher than 1.8 g/cm3. microscopic testing of organic matter in transitory, refl ected and blue fl uorescent light was conducted on an olympus bh-2, olympus bx-51 microscope and leitz mpv-3 microscope photometer. the arithmetic mean of vitrinite refl ection was measured. in a maceral system, amorphic organic matter was discerned (fl uorescent-nonfl uorescent), and also liptinite macerals (alginite, dinofl agellates, sporinite, liptodetrinite), vitrinites and inertinites. the sulphur content in the kerogen was determined on a sulphur analyzer leco sc-144 dr using the accredited method astm 4239-05. soluble organic matter (bitumen) was procured by extracting ground samples of rock in a soxhlet apparatus by chloroform refl ux over 36 hours. excess solvent was removed using rotational evaporation at 50°c, and the quantity of bitumen was determined after drying in a vacuum desiccator. the extractable organic matter (eom) content of the ground samples was determined using a 36-hour long soxhlet extraction by chloroform. chromatographic-gas analysis of the alkali fraction of bitumen was done on a gas chromatograph varian 3900 equipped with a capillary column (50 m x 0.25 mm). 2.5. interpretation of seismic sections and documentation regarding deep borehole cores – petroleum geological research seismic sections and documentation regarding cores from exploration boreholes were analyzed and interpreted with the goal of corelating karpatian, badenian and sarmatian sediments at depth in the drava depression with the badenian and sarmatian sediments discovered at “bukova glava”. table 1: results of basic petrophysical analyses sample porosity* % permeability* 1x10–³μm² horizontal vertical sc42 15.5 0 0.04 16.1 2.2 0 sc38 53.6 0 0 sc34 35.8 5,714.00 0 sc27 24.9 0.22 0 sc 21 12.4 0 <0.01 11.4 <0.01 0 sc14 21.2 0 0 *-md = 1 x 10–³ μm² geologia croatica 63/2geologia croatica 230 on the seismic sections, the basement mountains were denoted, that is to say the e-log datum tg and the boundary between the fi rst and second neogene megacycle (velić et al., 2002), or more precisely e-log marker rs7. with the data obtained from seismic sections as well as from documentation regarding core analyses from deep boreholes, a clearer picture on the distribution and thickness of badenian and sarmatian sediments was gained. data from the boreholes bankovci–1, bankovci–2, koška–2, đurđenovac–1 and našice–1, as well as seismic sections bk-5v-84, cr2v-84, bv-25-94, klok-16-81, na-1-94 and is-2-84 were analyzed. locations and the spatial distribution of deep boreholes and seismic sections in regards to the site of ”bukova glava“ are shown on fig. 13. 2.6. analysis of documentation of shallow boreholes lithological and chemical data were interpreted from cores of the 18 shallow boreholes drilled for calculation of material reserves and also to enable correlation of sediments and compile the data into a single unit, i.e. a synthetic column. data regarding the content of sio2 and caco3 were particularly useful and interesting as they facilitated reliable correlation both laterally and vertically in terms of geological age. 3. research results 3.1. results of palaeontological research at “bukova glava” numerous macrofossils and microfossils were recovered. among the macrofossils molluscs including amussium, macoma, corbula, and cerastoderma) are particularly numerous, together with snails, polychaetes (serpula), bryozoans, urchins (schizaster) and fi sh. various fragments of fossil macrofl ora are also commonly present. among the microfossils collected, foraminifera are the most numerous with a total of 29 species, of which 28 are of benthic and one of planktonic origin (table 2). in the basal 12m of the column, in which petroleum source rocks were defi ned, dark green and light gray laminae of marl alternate, and samples (sc1–sc13) were collected at 30 centimetre intervals. foraminifera are rare in these sediments, and mostly concentrated in lighter laminae, and the eurivalent taxa elphidium and cibicides are dominant. samples taken in the middle part of the column (sc15 do sc26) contain small benthic taxa (bolivina, bulimina, uvigerina) typical for the bulimina–bolivina zone of the upper badenian. the planktonic foraminifera globigerina bulloides appears for the fi rst time in a layer from which sample sc13 was taken, and is more frequent in samples sc15–sc18, which indicates a deepening and/or a strong connection with open seas. the genus globigerina appears for the last time in sample sc26, and is completely absent in subsequent samples, which suggests a shallowing upward trend and a change of the regime of sedimentation in the pool. in the upper third of the column, biodiversity decreases, and foraminifera are slowly replaced by ostracods. among the foraminifera, the tolerant taxa elphidium and cibicides are prevalent. 3.2. results of petrological analyses two samples, ptc1 and ptc2 were analyzed, to correlate the data from rock outcrops on the northern slopes of mt. krndija with the data obtained from bore holes located in the deeper parts of drava depression in order to determine the composition of basement highs. on the basis of microscopic investigation, sample ptc1 was classifi ed as mylonite, which originated by intensive deformation of granite or gneiss. sample ptc2 is also metamorphic rock, having been deformed under the infl uence of relative high pressure and temperature and is determined as a tourmaline garnet micaschist. both samples belong to the “basement highs“, namely to rocks underlying the neogene sequences. microscopic investigation of sample sc1 revealed that it is tuffaceous carbonate sandstone. fragments of volcanic glass being completely devitrifi cated by chlorite formation are present in the sample (fig. 5). usually, coarsely recrystallized calcite is visible around such devitrifi cated fragments. it is possible, that this calcite recrystallization was not only the consequence of diagenesis, but also of elevated temperature. numerous rock fragments having lenticular form and parallel orientation with respect to each other occur in this sample (fig. 6), and are most likely marls in composition. sometimes, rims of thinly and unequally distributed brown altered biotite and black kerogen (fig. 6) are developed around these rock fragments. also, rare muscovite and grains of quartz and zircon occur in the sample. the cement is calcitic, but calcite grains have an uneven grain size. 3.3. permeability and porosity results basic petrophysical analysis of six samples (sc42, sc38, sc34, sc27, sc21 and sc14), as shown in table 1 was perfi gu re 5: fragments of volcanic glass in the devitrifi cation process altered to chlorite. they are surrounded by coarsely recrystallized calcite. zečević et al.: signifi cance of the badenian petroleum source rocks from krndija mt. (pannonian basin, croatia) geologia croatica 231 ta bl e 2: d et er m in ed m io ce ne fo ra m in ife ra a t t he “b uk ov a gl av a” lo ca lit y geologia croatica 63/2geologia croatica 232 formed in order to determine their petrological characteristics i.e. analysis on the basis of permeability and porosity, and characterization as collector or cap rocks. four samples (sc38, sc34, sc27 and sc14) are defi ned by a porosity greater than 20%, while the remaining two (sc42 i sc21) have a porosity below 20%. indirect comparison of the synthetic column with the displayed fossil and lithological content (fig. 4) and the table of results of the basic petrophysical analyses (tab. 1) illustrates the petrophysical and lithological characteristics of rocks which contain individual fossil communities. 3.4. results of organic geochemical analyses five rock samples were chosen from the lowest part of the synthetic column and subjected to organic geochemical analysis (fig. 7). the organic matter content in collected samples varies from 0.48 to 13.5 % toc. samples sc16 (a, b) contain 0.48 and 0,52% organic carbon respectively, are of low generative potential, (s2, tab. 3), and their organic matter was partially changed by oxidation (oi, tab. 3). as per pyrolytic and optical parameters, the organic matter is immature, and kerogen is of type iii (fig. 8). there are no characteristics of source rocks. in contrast, samples of silty marls sc13, sc3 and sc1 (table 3) show high levels of organic matter content which resulted in increased residual potential values (s2, tab. 3). analytical results highlight the similarity between the samples. values of genetic potential are in line with the organic matter contents. the sample containing the highest organic matter content also has the highest value of residual potential, as confi rmed using rock eval pyrolysis (s2=74.52 mg hc/g rock). a fair generative capability was also confi rmed using pyrolysis on the extracted samples. it can be concluded that the rocks from all three layers of the lowest part of the column have very good to excellent characteristics of source rocks (hunt, 1995; waples, 1985). increased hydrocarbon potential is the effect of a favourable type of organic facies, e.i. type ii kerogen (fig. 8). microscopic evaluation of the isolated organic matter determined that the rocks contain mostly (75–80%) amorphic organic matter of an uneven, but intense colour of fl uorescence ranging from ochre yellow over yellow orange to brown orange. in its maceral structure, there is an extremely high content of hydrogen rich liptinite macerals of sporinites and liptodetrinites (15–20%), while vitrinite macerals only form up to 5% with a trace of inertinite macerals of fusinites and semifusinites (tyson, 1995; taylor et al, 1998). liptite macerals have marked yellow fl uorescence. the vitrinite maceral group is represented by two different macerals: a low-refl ecting desmocolinite and telocolinite. the low refl ection of desmocolinites is connected with submifi gu re 6: rock fragments (probably marls in composition) are characterized by rims of thinly and unequally distributed brown altered biotite and black kerogen. fi gu re 7: display of part of the outcrop at bukova glava on which the lower part of the synthetic column was recorded with the location of sample sc13 indicated. table 3: results of determining organic carbon content, rock eval pyrolysis and extraction for samples sc1, sc3, sc13, sc16a and sc16b. sample tocleco % tocre % s1 s2 s3 tmax °c pi s2 s3 hi oi min c % extract ppm*=extracted sample mg hc mg hc mg co2 mg hc mg co2 g rock g rock g rock g toc g toc sc16b 0.48 0.55 0.08 1.26 1.05 407 0.06 1.2 229 191 3.14 400 sc16a 0.52 0.61 0.08 1.47 1.09 404 0.05 1.35 241 179 2.83 994 sc13 8.9 7.62 2 48.82 4.61 409 0.04 10.59 641 60 3.29 2844 sc3 7 6.47 1.29 35.93 3.32 417 0.03 10.82 555 51 2.28 3172 sc3* 0 5.9 1.23 34.62 3.47 416 0.03 9.98 587 59 2.25 0 sc1 13.5 12.28 3.65 74.52 4.69 416 0.05 15.89 607 38 1.65 4598 sc1* 0 12.35 3.34 73.41 5.11 414 0.04 14.37 594 41 1.35 0 zečević et al.: signifi cance of the badenian petroleum source rocks from krndija mt. (pannonian basin, croatia) geologia croatica 233 croscopic lipid intercalations which derive from the anaerobic (bacterial) breakdown of cellulose (taylor et al., 1998). microscopically a rare occurrence of sulphur in the form of pyrite (framboidal pyrite) was also determined, and the remaining sulphur is chemically bound within a macromolecule of kerogen. the concentration of total sulphur in the kerogen is 8.77−13.02 %, which supports the theory of sedimentation in a marine environment. optical maturation parameters tai (1+–2–, conversion <0.35%ro), the yellow-orange hue of fl uorescence as well as of measured vitrinite refl ection (0.25 and 0.26 % ro) indicate an immature, diagenetic phase of thermal transformation of organic matter. the value of maximum temperature of pyrolysis (tmax 409–417°c; tab 3, fig. 9), further supports this. therefore, the samples have the characteristics of an immature core rock. in the analysed samples, a heightened quantity of less soluble bitumen was also determined 2844 to 4598 ppm. high n-alkane content and a hydrocarbon chain spanning c11–c35 characterize a gas chromatograph profi le of the bitumen. however, these results show signs of a bimodal distribution, but loss of hydrocarbons of the lower molecular domain is probable. the bimodality of the distribution determines a mixed origin and suggests a heightened content of terrestrial lipids in an originally algal organic matter. the prevalence of hcs in a higher molecular domain (c27, c29, c31) as well as the domination of uneven hcs over the even ones (cpi>>1) confi rm the results of the microscopic analysis, i.e. the heightened content of hydrogen rich lipids of the higher plants and the immaturity of bitumen (tissot & welte, 1984). the pr/ph relations speak in favour of an anoxic to suboxic environment of organic matter sedimentation. as a result of the absence of lighter hydrocabons (the sample in question is a surface sample) determining the maturity of bitumen is dubious. with certain reservations regarding the bitumen maturity, it can still be safely concluded that the aforementioned parameters of bitumen are in accordance with the defi ned organic facies and the generative potential of the core rock. 3.5. results of petroleum-geological research stratigraphic, micropalaeontological, geochemical, bitumenological-luminiscent, and similar data was used in order to reconstruct the geological and petrological conditions of neo gene sediments within the deeper parts of the drava depression, as mentioned previously by kranjec et al. (1976). it should be noted that chronostratigraphic analysis of the neogene during the drilling of the aforementioned boreholes was somewhat different, layers had different names and ranges. a similar situation is applicable to the badenian period (previously known as the tortonian) which is today subdivided into lower, middle, and upper, (while the tortonian was subdivided into the lower and upper divisions). ban–1 and ban–2 (bankovci–1, –2) boreholes can be subdivided into lower middle and upper on the basis of borefi gu re 8: modifi ed van krevelen diagram. fi gu re 9: modifi ed hi-tmax diagram. geologia croatica 63/2geologia croatica 234 hole documentation, because the lithology (and to a lesser extent the relatively comprehensive palaeontological content) of the badenian and the sarmatian sediments in these two wells was also identifi ed in the “bukova glava” synthetic column. an attempt at such analysis was made (but with limitations) for the đurđenovac–1 and koška–2 boreholes. comparison with the “bukova glava” column is not easy to achieve because of different lithological characteristics and poor palaeontological data. it must also be mentioned that there is a 500m interval (from 1350–1850m depth) that contains no samples and is therefore chronostratigraphically undetermined in the đurđenovac–1 well. within this interval, there is a boundary between the basement rocks and the fi rst neogene megacycle which can be confi rmed and located on the basis of seismic data, and as such is integrated in the table display of the đurđenovac–1 borehole within the stratigraphic range of deep boreholes. data for the na–1 (našice–1) borehole are the poorest and exist only in the form of a short text description of the borehole. it was drilled 50 years ago and has no graphic or stratigraphic description, and the palaeontological data are generalized and for the badenian base restricted to a few lines of text. despite these problems, thicknesses of the 1st neogene megacycle (fig. 2) can be displayed with a high percentage of accuracy for all fi ve analyzed boreholes. the “bukova glava” column is best correlated with the stratigraphic display in the research borehole bankovci–2 (ban–2) shown in fig.12. hydrocarbons were not detected in the boreholes, nor were petroleum source rocks, which does not defi nitely exclude the possibility of their past or present occurrence. for example, in the đu–1 (đurđenovac–1) borehole samples from 1207–1210 m (top part of the 1st megacycle bordering the 2nd megacycle), contain elevated total organic matter (>0.5 %), above the contiguous in estimation of source rocks, in relation to deeper intervals. however the results of pyrolysis indicate a very small quantity of residual organic matter; in other words they don’t suggest the possibility of gas and oil generation. organic matter is on the border of maturity (tmax=434°c). on this basis it can only be partially deduced that the drilled badenian sediments have no petroleum source intervals, nor an interval with adequate sedimentary properties. as the badenian sediments on the northern slopes of mt. krndija on the “bukova glava” are good petroleum source rocks, the question arises as to whether source rocks lie more to the edge of the depression where organic matter was deposited in isolated lagoons and coves. these are areas where alongside the original organic matter of aquatic, i.e. algal origin, a signifi cant amount of lipid components of prevalently terrigenous origin is also represented (for example in the badenian sediments of the lower synthetic column, sc1– sc13, dinocysts of bisaccates occur – pinus, picea and abies). thicknesses of badenian sediments increase from the edges towards the deeper parts of the depression, but the petroleum source potential of the sediments decreases, which can be connected to the distance from the coastline to which depositional, i.e. palaeoecological conditions favourable for the accumulation and preservation of organic matter are tied. 3.6. results of the analysis of shallow borehole documentation lithological and chemical data from the cores of 18 shallow exploratory boreholes drilled by the “nexe grupa” company in the “tajnovac” quarry, were analysed in order to correlate the deposits and determine the relationships between sio2 and caco3 in space and time. a relative increase of the sio2 component with regards to caco3 was noted in the sequence of sediments ranging from the youngest to the oldest, and a relative increase of the proportion of the sio2 component in relation to caco3 ranging from north to south. 4. discussion 4.1. biostratigraphic discussion the fossils recovered at “bukova glava” belong to the fi rst neogene megacycle (lower-to-middle miocene) according to velić et al. (2002). the diverse microfossil assemblage in the middle part of the column is of particular interest. the oldest sediments outcropping at the surface are laminated marls. lighter laminae are interbedded with darker laminae of tuffi tic marls and sandstones. in the darker laminae there is virtually no trace of life, while in lighter laminae macoma and arca bivalves were discovered, as well as carbonized fi sh and rare members of tolerant taxa of foraminifera (of which the genera elphidium and cibicides are the most common). palynological analysis has shown that a large percentage of pollen grains of conifers, transported from land, occur alongside marine dinocysts lingulodinium machaerophorum, systematophora placacantha and spiniferites ramosus, (k. bakrač, pers. comm.). due to the stressful environment, there are no index taxa in these sediments. their age is older than the upper badenian, because the bulimina–bolivina zone was proven in the overlying deposits. ćorić et al. (2009) link the tuffi tic volcanism in this region to the lower badenian, so we can assume the age of these sediments, or at least a part of them, to be lower badenian. fossiliferous marls and marly limestones in the middle part of the column (samples sc15–sc26) contain fl ora and fauna characteristic of the lower part of the upper badenian, the bulimina–bolivina zone (đ. pezelj, pers. comm.). bolivina, bulimina and uvigerina genera dominate, as they are represented by a larger number of species (tab. 1), and there is a high percentage of the planktonic species globigerina bulloides. the accompanying fl ora and fauna is also typical of the upper badenian in paratethys, as corallinacean algae, bivalves (chlamys, amussium, corbula) snails, bryozoa, polychaeta (serpula) and urchins (schizaster, numerous radiolae) frequently occur. zečević et al.: signifi cance of the badenian petroleum source rocks from krndija mt. (pannonian basin, croatia) geologia croatica 235 in the layer from which sample sc27 was taken there is an abrupt decrease of fossils, and subsequently only cibicides and elphidium can be found in marls, up to the level of sample sc38. the foraminiferal assemblage of sarmatian age appears from the horizon with sample sc27 onwards (đ. pezelj, pers. comm.). in the same samples, ostracods and snails appear, together with the bivalve macoma, as well as carbonized fi sh. bioturbation and parallel lamination, low biodiversity, and the prevalence of opportunistic euryhaline species, suggest a shallowing upward trend and increased input of fresh water into the pool. echinoid radiolae can still be discovered in the sediments, which were probably redeposited from older horizons. sediments between horizons sc28–sc38 are marked as transitional, because they contain only opportunistic microfossil species of low stratigraphic value, typical for stressful environment. the upper boundary of this sediment package is marked by an erosional surface. in sample sc38 prasinophyceae appear for the fi rst time, such as mecsekia sp, cymatiosphaera miocenica and cymatiosphaera sp., together with terrigenous palynomorphs. in samples s39 and sc40 there are neither macrofossils, nor foraminifera, and in sample sc42 the bivalves cerastoderma latisulcum and c. vindobonense vindobonense occur. therefore the sediments in the upper part of the column (above horizon sc38) were designated to be of sarmatian age. 4.2. petroleum – geology discussion deposition of petroleum source rocks in the lower part of the synthetic column (ranging from sc1 to sc13) (fig. 4) occurred in lagoon conditions in rugged environments of low water energy (fig. 11), where sedimentation of calcitic clay, silt, and sand (grey-white layers) took place. periodic volcanic activity in the form of an eruption and release of volcanic ash in the region of the slavonian mountains (and possibly more remote regions as well) led to a cyclic pattern of sediments – tuffaceous calcitic marly sandstones ranging from dark green to black in colour with a grey-white calcitic clays, marls and marly sandstones. tuffaceous marly sands were deposited in reducing conditions as indicated by the presence of framboidal pyrite. reduced ph conditions with a lack of caco3 component are related to more pronounced sedimentation of sio2 detritus. a few small individuals of the genus elphidium occur, in the grayish-white sediments represented by elphidium crispum, e. aculeatum and e. macellum, while in the dark green tuffaceous layers there are virtually no foraminifera. during deposition of these sediments open marine infl uences are lacking, and the planktonic foraminifera globigerina bulloides only appears in layer sc13. the proximity and impact of land is indicated by a considerable amount of liptinites of terrigenous origin (sporinite), as are traces of a maceral of the huminite-vitrinite variety in the content of organic matter, and the increased percentage of hydrogen rich lipids of higher plants in the molecular distributions from segregated extracts (molecular area c27, c29, c31). microscopically, rare chemical compounds of sulphur in the form of pyrite (framboidal pyrite) were also determined, while the remaining sulphur was chemically bound within a macromolecule of kerogen. these parameters determine an anoxic marine environment of deposition. fine lamination and lack of sedimentary textures, including bioturbations, are typical for this formation. the sedimentary area expanded during the deposition of the badenian rocks, which indicates a system of synsedimetary normal microfaults of the domino-type in the lower part of the synthetic column, ranging from layers sc1 up to sc13 (fig. 10). on the basis of lithological and textural attributes and the fossil content, it can be concluded that the sediments in question belong to a protected lagoon (fig. 11) or a partly closed bay, in which rivers and precipitation carried clastic material from the slopes of mt. krndija. figure 11 shows the process of organic matter accumulation, which took place in the lower badenian during formation of layers sc1–sc13. because the lower badenian sediments reach a pronounced palaeorelief with a crystalline base, they fi ll the area with large sideway shifts in thicknesses in the coastal regions. in the background lie the krndija massif and a stream/river fl ow. on the same picture the position of section a–b is shown, together with the model of organic matter accumulation in a partially protected lagoon. the occasional and limited infl uence of the open marine environment on the lagoon and large stream or river fl ow, which transported detritus from the slopes of krndija into the lagoon is depicted using arrows. accumulation and transformation of organic matter took place in the deeper parts of the protected lagoon, together with sedimentation of tuffaceous calciferous marly sandstones, and salty marls ranging from dark green to black in colour, i.e. accumulation and sedimentation of volcanic ash, or grey white calciferous clays, marls, and marly sandstones in between volcanic eruptions (figs. 11a, 11b). the petrophysical attributes of certain rocks which chronologically, superpositionally overlie the basal deposits of the column (sc1–sc13) have the characteristics of prime fi gu re 10: system of normal microfaults of the domino-type in the lower part of the synthetic column. geologia croatica 63/2geologia croatica 236 reservoir rocks. these are especially pronounced in samples sc14, where porosity reaches 21.2%, sc34 with a porosity of 35.8% (permeability 5.714,00 x 10–3 µm2) and sc38 with a porosity of up to 53.6%, (a very high value which should be analysed by further research). the stratigraphic display (fig. 12) of the research borehole bankovci–2 (ban–2) situated approximately 13 km north of the “tajnovac” cement plant, is similar to the lithology of the open profi le on the “bukova glava” section. the mountains granite core is overlain by pyroclastites, then by marly sandstones, and fi nally by very fossiliferous marls, as in the synthetic column. three locations in the analyzed interval from the stratigraphic display of the research borehole bankovci–2 have source rock attributes. the “tortonian” (badenian) basement, in the stratigraphic display is 247 metres thick and is classifi ed as the “lower tortonian”. the interval within the research borehole bankovci–2 (1436–985 m) which contains pre-tertiary basement (granites), pyroclastites, marly sandstones and sandy fossiliferous marls, can be correlated with the synthetic column on the “bukova glava”. on the basis of foraminifera, the interval could be determined as upper badenian in age, because it contains a microfossil community of the bulimina–bolivina zone. the genera bolivina and elphidium are absent from the community, which leads to the conclusion that the borehole bankovci–2 reached sediments deposited away from the badenian coastline. it is interesting to note that in the stratigraphic display of the research borehole bankovci–2, the pyroclastics which lie on the basement rocks are placed slightly below the “tortonian” (badenian). however, we consider that the pyroclastics in the borehole bankovci–2 can be determined as badenian (in the synthetic column they are marked as the lower badenian). in addition to the superpositional location within the synthetic column and the fossil composition which indicates a badenian age, there are a number of papers which place the pyroclastics of mt. krndija and the surrounding fi gu re 12: a comparison of the stratigraphic subdivision of part of the deep borehole bankovci–2 by the original analyst (šimon, 1974) and the stratigraphic subdivision of the cores from the borehole in light of the new data. fi gu re 11: an idealized display-reconstruction of the environment in which the processes of production, accumulation and transformation of organic matter in an aquatic surrounding (lagoon) took place. zečević et al.: signifi cance of the badenian petroleum source rocks from krndija mt. (pannonian basin, croatia) geologia croatica 237 mountains mostly into the lower, or lower and middle badenian (krkalo & mutić, 1978; pamić & pecskay, 1996; krkalo, 1998). also, it is signifi cant to note that on the stratigraphic display of the research borehole bankovci–1 which is situated only a few kilometres away from borehole bankovci–2, the pyroclastics which lie on the basement rocks (micaschist) were indicated as being of “lower tortonian” age. on the profi le through the boreholes bankovci–1 – bankovci–2 – koška–2 – đurđenovac–1 – našice–1, the pyroclastics in the research boreholes bankovci–1 and bankovci–2 are correlated, i.e. were deposited at the same time and over the same area. it can be assumed that they belong to the lower part of the lower badenian as well as the pyroclastics in the synthetic column on the site of “bukova glava”. the stratigraphic display in the deep research borehole bankovci–2 therefore differs signifi cantly from the interpretation and provisions of šimon (1974) who had placed the “tortonian” (badenian) sediments mostly in the “lower tortonian” (with the exception of the borehole bankovci-2 where alongside “lower tortonian” “upper tortonian” was also displayed) or just defi ned as “tortonian” without subdividing the aforementioned geological epoch. according to the graphically displayed conclusions of perković (1975, 1978); šimon, (1974) and brodarić, (1985), the “upper tortonian” (upper badenian) and sarmatian are completely absent from the deeper part of the drava depression around našice. this does not agree with the all-encompassing research carried out by kranjec et al. (1976), nor with the geophysical and hydrogeological research on the slopes and boreholes carried out by šumanovac et al. (2003) at “seona” on the northern slopes of the mt. krndija. differing standards of subdivision and defi nition of the “tortonian” (as well as the neogene), at the time when the boreholes were drilled, and lack of comparison with surface outcrops, are the most likely explanations for the discrepancy in thickness. the isopach map (fig. 13) of the badenian sediments was created in accordance with the data which were collected in the fi eld and laboratory research on the “bukova glava”. during the creation of this map, the data from the “seona” (šumanovac et. al., 2003) were taken into account, as was the data from the regional research published by kranjec et al. (1976), as well as the seismic sections as spatially distributed as shown in fig. 13. on the isopach map, an expected thickening of the badenian sediments towards the centre of the drava depression is visible. badenian sediment thickness north of našice increases rapidly from 150 to 350 metres. fi gu re 13: isopach map of the badenian sediments of the northern slopes of mt. krndija and the southern boundary area of the drava depression in the vicinity of našice with the marked locations of exploration wells, seismic sections and the site of “bukova glava”. geologia croatica 63/2geologia croatica 238 5. conclusion the development of the badenian sediments on the northern slopes of mt. krndija was characterized by very diverse environments on a slightly sloped basement on which synsedimentary tectonics had a signifi cant infl uence. the well-developed palaeorelief of mt. krndija played a crucial role in the creation and modifi cation of the depositional environment, as refl ected in the fl anking and vertical changes of facies. furthermore, synsedimentary tectonics and the dynamics of the depositional area, particularly elevation of mt. krndija and the spread and subsidence of the depositional basin during the badenian, together with regression in the uppermost part of the badenian caused by synergistic activities of land rise and sea level fall were also important. as a consequence of tectonics and eustatic changes in paratethys, a shallowing upward trend occurred in the study area on numerous occasions. it is also likely that there was an emersion phase as well (visible at the boundary between layers sc38 and sc41). badenian sediments are characterized by the greatest variations in thickness of all the geological stages of the miocene. the badenian sediments which overlap periclinally on the papuk–krndija massif mostly match the former sea belts or environments of sedimentation such as bays and lagoons, where the changing sea levels are strongly refl ected, together with spatial extension and the rise of massifs and subsidence of the depositional basin. since the sedimentary area during the badenian steadily subsided and was broadened, the shifting of the coast line and the space of clastic deposition was caused by an uneven transport of material due to the seasonal infl uence of rains, as well as the varying intensity of erosion of parts of the rising terrain/land. contours of sedimentary elements visible on the seismic profi les mark periclinal overlaps on the northern slopes of mt. krndija as a consequence of the aforementioned palaeogeographical circumstances. the diversity of environments, i.e. the enviroment of the protected lagoon/bay and a high rate of bioproduction, created ideal conditions for the accumulation of organic matter which was displayed in the petroleum geological model (figs.11a,b). an increased organic carbon content and the favourable hydrocarbon potential of these rocks are the consequence of a particular type of organic facies, type ii kerogen, mostly of marine algal origin, but with an increased content of terrigenous lipids. the presence of tuffi tes in the rocks with a considerable concentration of carbon suggests that volcanic activity infl uenced anoxic conditions (a decrease in ph) and signifi cant changes of palaeoecological conditions, which occurred cyclically. additional evidence of a marine environment and anoxic conditions of sedimentation are the increased quantity of framboidal pyrite, and the increased content of organically bonded sulphur and the domination of phytane over pristane in the gas chromatographic distributions of bitumen extracted from the source rocks. the genesis of this part of the analyzed sediments is tied to very reducing conditions of sedimentation which govern in protected lagoons/bays of relatively shallow seas. the lithological composition of rocks on the edges of the slavonian mountains can serve as input data for the creation of a 3d computer model which could by analyzing palaeostructural and palaeotectonic relationships simulate the time and possible routes of hydrocaron migration. this provides the possibility for collecting new information for petroleum exploration. furthermore, the data on rock permeability and porosity can be used in various geostatistical analyses of the badenian sediments, to correlate the data from the boreholes in the drava depression with those obtained on the edge of mt. krndija. acknowledgement we acknowledge to colleagues and associates: koraljka bakrač for the analysis of dinofl agellates, đurđica pezelj for help in interpreting the microfossil community, željko bortek for the signifi cant logistic support and josip bubnić for access to the archive of the petroleum company ina oil industry. the study was funded by the ministry of science, education and sports of the republic of croatia, the projects “stratigraphic and geomathematical explorations of petroleum systems in croatia” (195-1951293-0237), by the main researcher professor dsc josipa velić and “evidence of biotic and abiotic changes in fossil environments” (119-1951293-1162) by the main researcher professor dsc jasenka sremac, which is a part of the scientifi c program “cenozoic geological processes-control on environment and fl uids reservoira” which professor dsc josipa velić leads. references agip s. p. a. (1982): foraminiferi padani (terziario e quaternario).− atlante iconografi co edistribuzione stratigrafi ca, pls. 52. brodarić, a. (1985): stratigrafski prikaz duboke istražne bušotine đurđenovac–1 [stratigraphic review of the deep exploratory well đurđenovac–1 − in croatian].– unpubl. report, ina oil industry, zagreb, 13 p. cimerman, f. & langer, r.m. (1991): mediterranean foraminifera.− slovenska akademija znanosti in umetnosti, ljubljana, 119 p. ćorić, s., pavelić, d., rögl, f., mandic, o., vrabac, s., avanić, r., jerković, l. & vranjković a. (2009): revised middle miocene datum for initial marine fl ooding of north croatian basins (pannonian basin system, central paratethys).– geol. croat., 62/1, 31−43. croatian geological survey (2009): geological map of the republic of croatia 1:300.000.– croatian geological survey, zagreb. espitalie, j., deroo, g. & marquis, f. (1985): rock-eval pyrolysis and its applications.– institut francais du petrole, 72 p. gorjanović-kramberger, d. (1891): palaeoichthyoložki prilozi (collectae palaeoichthyologicae). dio ii.– rad jazu zagreb, 106, 59−129. harzhauser, m., mandić, o. & zuschin, m. (2003): changes in paratethyan marine molluscs at the early/middle miocene transition: diversity, palaeogeography and palaeoclimate.– acta geol. pol., 53, 323−339. hernitz, z. (1983): subsurface structure and tectonic relations in the area of eastern slavonia. (geol. d. thesis).– nafta, spec. issue, 221 p. zečević et al.: signifi cance of the badenian petroleum source rocks from krndija mt. (pannonian basin, croatia) geologia croatica 239 hernitz, z., velić, j. & barić, g. (1995): origin of hydrocarbons in eastern part of the drava depression (eastern croatia).– geol. croat., 48/ 1, 87−95. hernitz, z., vrbanac, b., pavlović, z. & bokor, n. (2002): on the exploration level of the croatian part of the pannonian basin.– nafta, 53/10, 363−370. hernitz, z., tišljar, j., kalac, k., velić, j. & jelić, k. (1993): miocenski siparni i priobalni klastiti te matične stijene u dravskoj depresiji [miocene colluvial and coastal clastic deposits and source rocks in the drava depression − in croatian].– hazu, znanstveni savjet za naftu, savjetovanje o kolektorskim stijenama u panonskom bazenu, 1−2. hörnes, m. (1856): die fossilen mollusken des tertiär-beckens von wien. 1. band. univalves.– abh. k.k. geol. reichsanst., 1−10, 1−736. hottinger, l., halicz, e. & reiss, z. (1993): recent foraminifera from the gulf of aqaba.– slovenska akademija znanosti in umetnosti, 230 p. hunt, j.m. (1995): petroleum geochemistry and geology.– w. h. freeman and company, san francisco, 743 p. ics (2008): international stratigraphyc chart.– international commission on stratigraphy. kranjec, v., hernitz, z., reščec, t. & velić, j. (1976): some results of subsurface mapping in the drava river depression.– nafta, 27/3, 123−141. krkalo, e. (1998): neogene quartz sand deposits from the marginal parts of the slavonian mountains (croatia).– institute of geology, zagreb, 174 p. krkalo, e. & mutić, r. (1978): tuffs in lower tortonian deposits of nježić area near slavonska požega, north croatia.– geol. vjesnik, 30/2, 344−350. lučić, d., saftić, b., krizmanić, k., prelogović, e., britvić, v., mesić, i. & tadej, j. (2001): the neogene evolution and hydrocarbon potential of the pannonian basin in croatia.– marine and petroleum geology, 18, 133−147. malvić, t. (2006): middle miocene depositional model in the drava depression described by geostatistical porosity and thickness maps (case study: stari gradac – barcs nyugat fi eld).– the mining-geological-petroleum engineering bulletin, zagreb, 18, 63−70. mandić, o. (2004): pectinid bivalves from the grund formation (lower badenian, middle miocen, alpine-carpathian foredeep) – taxonomic revision and stratigraphic signifi cance.– geol. carpathica, 55/2, 129−146. pamić, j. & pecskay, z. (1996): geological and k-ar ages of tertiary volcanic formations from the southern part of the panonian basin in croatia – based on surface and subsurface data.– nafta, 47/6, 195−202. papp, a. & schmid, m.e. (1985): die fossilen foraminiferen des tertiären beckens von wien.– abh. geol. bundesanst., wien, 37, 1−311. pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.– basin research, 13/3, 359−376. pavelić, d., avanić, r., kovačić, m., vrsaljko, d. & miknić, m. (2003a): an outline of the evolution of the croatian part of the pannonian basin system.– 22nd ias meeting of sedimentology – opatija 2003, field trip guidebook, 155−161. pavelić, d., kovačić, m., miknić, m., avanić, r., vrsaljko, d., bakrač, k., tišljar, j., galović, i. & bortek, ž. (2003b): the evolution of the miocene environments in the slavonian mts. area (northern croatia).– 22nd ias meeting of sedimentology – opatija 2003, field trip guidebook, 173−181. perković, a. (1975): stratigrafski prikaz duboke istražne bušotine bankovci–1 [stratigraphic review of the deep exploratory well bankovci–1 − in croatian].– unpubl. report, ina oil industry, zagreb, 8 p. perković, a. (1978): stratigrafski prikaz duboke istražne bušotine koška-2 [stratigraphic review of the deep exploratory well koška–2 − in croatian].– unpubl. report, ina oil industry, zagreb, 4 p. prelogović, e., saftić, b., kuk, v., velić, j., dragaš, m. & lučić, d. (1998): tektonic activity in the croatian part of the pannonian basin.– tectonophysics, 297, 283−293. rögl, f. & brandstätter, f. (1993): the foraminifera genus amphistegina in the korytnica clays (holy cross mts, central poland) and its signifi cance in the miocene of the paratethys.– acta geol. pol., 43/2, 121−146. saftić, b., velić, j., sztano, o., juhasz, g. & ivković, ž. (2003): tertiary subsurface facies, source rocks and hydrocarbon reservoirs in the sw part of the pannonian basin (northern croatia and south-western hungary).– geol. croat., 56/1, 101−122. steininger, f.f., müller, c. & rögl, f. (1988): correlation of central paratethys, eastern paratethys, and mediterranean neogene stages.– in: royden, l.h. & horvath, f., (eds.): the pannonian basin. a study in basin evolution.− am. assoc. petrol. geol. mem., 45, 79−87. šimon, j. (1974): stratigrafski prikaz duboke istražne bušotine bankovci–2.– ina oil industry [stratigraphic review of the deep exploratory well bankovci–2 − in croatian].− unpubl. report, zagreb, 7 p. šumanovac, f., urumović, k. & dragičević, i. (2003): hydrogeological mapping of a miocene aquifer by two dimensional electrical imaging.– the mining-geological-petroleum engineering bulletin, zagreb, 15, 19−29. taylor, g. h., teichmüller, m., davis, a., diessel, c.f.k., littke, r. & robert, p. (1998): organic petrology.– gebrüder borntraeger, berlin–stuttgart, 704 p. tissot, b.p. & welte, d.h. (1984): petroleum formation and occurrence. 2nd ed.– springer, berlin, 699 p. tyson, r.v. (1995): sedimentary organic matter, organic facies and palynofacies.– chapman & hall, london-glasgow-winheim-new york-tokyo-melbourne-madras, 615 p. velić, j., tišljar, j., dragičević, i. & blašković, i. (2000): shoreline cross-bedded biocalcarenites (middle miocene) in the podvrško-šnjegavić area, mt. psunj, and their petroleum signifi cance (požega subdepression, eastern croatia).– geol. croat., 53/2, 281−293. velić, j., weisser, m., saftić, b., vrbanac, b. & ivković, ž. (2002): petroleum-geological characteristics and exploration lavel of the three neogene depositional megacycles in the croatian part of the panonian basin.– nafta, 53/6–7, 239−249. vrsaljko, d. (2007): značajni geološki lokaliteti bukova glava i vranović [significant geological localities bukova glava and vranović – in croatian].– in: kranjčev, b. (ed.): zoljan jučer i danas. valenček d.o.o. našice, 159−173. waples, d.w. (1985): geochemistry in petroleum exploration.– international human resources development corporation, boston, 232 p. wesselingh, f.p. (2006): moluscas from the miocene pabes formation of peruvian and columbian amazonia.– scripta geologica, 133, 19−290. zečević, m. (2008): naftnogeološko značenje, paleoekologija i biostratigrafi ja badenskih taložina sjevernih obronaka krndije [petroleum-geological signifi cance, palaeoecology and biostratigraphy of the badenian deposits at the northern slopes of the krndija mt. − in croatian, with an english abstract].– university of zagreb, faculty of mining, geology and petroleum engineering, unpubl. phd thesis, 178 p. manuscript received july 20, 2009 revised manuscript accepted december 15, 2009 available online may 31, 2010 geologia croatica 63/2geologia croatica 240 i geol. c roat. 50/2 173 180 2 figs. zagreb 1997 the development of croatian geoscience as reflected by the study of dinaridic ophiolites jakob pamic key words: dinaridic ophiolites, genetically rela ted sedimentary fo rmations, flysch period, geosyncline period, plate tectonics. abstract ror approxi mately 120 years since the beginni ng of eu ropean geology up to ihe present day. croatian geoscience has incl uded intens ive geological research of the dinaridc ophiolite zone. rese­ arch rcsll ll.~ can be grouped into severa l peri ods depending on the basic predominant approaches of eufope:\j1 and world geology. ( 1) during ihe nysch period, oph iolites were spati all y connected wi th the ilysch formations. (2) during the geosyncli nal period ophiolites were classi fi ed inlo the "dialxls-hornslcin fornmtion'·. (3) during thc tr.m­ sit ional periocl, characterized by thc elaboration or the basie geologi­ cal map, a voluminous data were co llec ted which could not be incor­ porated in geosyncl inal idcas. (4) the last per iod is charactcrizcd by modern geodynamic in terpretations resul ting rrom global tectonics. 1. introduction as carbonate rocks, limestones and dolomites char­ acterize the external unil s of the orogen ic belts, ophi­ olilic rocks (u ltramafi cs, gabbro, d iabase-basalt ) and genelica ll y related radio lar ite and clasti c formations represent a characteristic feature of the internal units of the phanerozoic orogenic systems. the ophiolitic com­ plexes or the orogenic belts represented one of the 111051 comp lex problems or world geology until the appear­ ance o r the idea of plate tectonjes. from the very begin­ ning or european geology to the present day, croatian geologists have been very acti ve in the investigation of ophiolites. with in the hugc mesozo ic alpine-himalayan bclt , the dinaridic ophi olilcs occupy an important pos ition, not only because o r their large quantites bu t also by their typi cal geologica l and petrological development. the dinaridic op hiolites st retch from the hrvatsko zagorjc mountains in the northwest and continuc a croatian academy o f sciences and arts, ante kovacica 5, hr -loooo zagreb, croatia. kljucne rijeci: di naridski ofioliti , genetski povczane sedimcntne form acije, oisno razdoblje, geos ink li­ nalno razdoblje, tektonika ploca. sazetak hrvatska je geoznanost, ad samih pocctaka ~\grebacke gcologijc sve do d:li13.snj ih dana 1i intervalu od oko 120 god ina, bi ta intenzivno ukljucenn 11 geolosko izucllvanj e ofioli tne zo ne dinarida. rezlll lllti lih istrazivjllja mogu se podijeliti u nekoliko razdoblja, ii zav isnost i od osnovnih prevladavajucih pri stupa curopske, od no sno svj etske geologije. ( i ) fli sno razdoblje. koje je orio litne stijcnc vczn lo za n isne tvorevinc. (2) geosi nkl inalno razdobtje. kojc jc ofioli tne stijene o buhvacalo u tzv. dijabaz-roznjacku ro rmaciju. (3) prij e lazno raz­ dobljc, koje se karakteriz ira izradom osnovne geoloske karle, odnos­ no prikuptjanjcm obimne raktografije koja se vise nije mogta tlunclciti gcosinktinalnom koncepcijom. (4) sadasnje razdoblje koje se karak· tcrizira 1ll0dcrnim geod in:llnskim illterpretacijama proizislim iz tek­ lonike ploe:l. nw-se direction through banovi na to bosnia and fur­ ther through serbia 10 the vardar zonc and mirdita zone of the noi1h hellenides (fig. 1). 2. chronological presentation of geological ideas 2.1. flysch period prior to inauguration of croatian geoscience and the first systematic inves tigations of ophiol ites, vukotj­ novic ( 1853) mentioned a findin g of serpentinites in mt. kalnik. croat ian geoscience started its development simulta­ neously wilh european geoscience. duro pilar, the fou ­ nder of croatian geology, was inc luded in the first investigmion of the dinaridic ophiolites at a time when the dinar ides had not been defined as a mountain sys­ tcm. he separated "cretaceous fly sch" in parts of the presen t dinaride ophiol ite zone, and emphasized thai this paper was presented at the scientific meeting dedicated to the 80th anniversary of the life of professor milan herak, held on march 5th, 1997 in zagreb 174 0, 12], _ 0 .0" ~,d" = r.':':'7l l..=..j f t::.:..::..:.:. 12 geologia croalic;t son n a iiiiiil d" o. el" 50 100 km -=-====' fig. i geological sketch-map of the dinaridcs and north hellenides showing ihe position o f the ophiolite complexes (pamle. 1982) . legend: i) carpathian s; 2) scrbo-macedoniall mass; 3) sumadija ilysch: 4) pelagonidcs :md korab: 5) mesozoic-palaeogene ca rbonate platform: 6) all ochthonous palaeozo ic-triassic complexes: 7) mesozoic clastics of the passive continental margin: 8) ophiolite zone; 9) ultramafic mas­ sifs: 10) radiojaril cs: 1 i) late cretaceouspalaeogene ilysch of the active co ntinental margin; 12) alpine granites and andesites: 13) nco­ gcnc-qu:ncrnary sedi mentary rock s; 14) transversal fault s. ultramafic mass ifs: z) zlatibor; v) yarda; sa) banija; k) kozara; lj) ljubic; b) bolje; 0) ozren; kk) kri vaja-konjuh ; ma) maljen; i) ibar: g) goles. transversal fau lts: z.l) zagreb zemplen; sa) sarajevo; sp) skadar­ pee. "thc latc cretaceous terminates in bosnia as in adja­ cen t countries by the flysch which includes large quan­ tities of igneous rocks" (pilar, 1882, p. 17), i.e., the ophiolites. he included sedimentary rocks surrounding ophiolites into the jurassic and cretaceous and was or the op inion that "the zone of igneous rocks represents only a facies within the flysch formations" (pilar , 1882, p. 5 1). he also emphasized the regional , geologi­ cal occurrence of ophiolites claiming that they stretched from bosnia northwes tward into hrvatsko zagorje in croatia. kispatic (1897, 1899) continued pi lar's work on the bosnian ophiolit es. his monograph "crysta lline rocks from the bosnian serpentinite zone" includes mainly petrographic data, but some were used for geo­ dynamic considerati ons. at that time kispatic clearly noticed that iherzolites, (predomi nan t ultramafic rocks), were characterized by typ ical metamorphi c fabrics. he recogn ized that these rocks have "a ligned" structure and that " the alignment does not represent an exception but a characteristic reature of the bosnian iherzolites" (klspatic, 1897, p. 226). based on these data kispatic (l897, p. 230) drew the heretical conclusion that "crystalline rocks from the bosnian serpentinite zone, except mejaphyres and dia­ bases, should be classified as crystalline schists and that they belong to archean rormations". characteristic par­ allel structures in iherzolitcs clearly indicate that these rocks originated in the same way as in associated amphiboli tcs and both of them represent primord ial rocks. if one bears in mind that the fundamental ideas con­ cern ing the uppe r mantic, mohorovicic di scontinu ity, asthenosphere etc., were unknown in the late 19th cen­ tury then it can be said that kispatic's ideas were nearl y ingenious. first of all , he noticed consanguinity of pamic: 'l1u! devclopmcn1 of cro:uian geoscience ;is reneet.;:d by the study of dinaridic ophiolites 175 ophiolite rocks which represent , indeed implay that they were, prim eva l rocks that camc from the " earth interior". due 10 the ract that these primordial rocks lie beneath tri assic and palaeozoic formation s, they could only have been considered to be on ly of an archean age according to ideas of that time. kispati c em ph asized that thc bosnian ophio litic rocks have regional s ignatures continu ing no rthwest­ ward into croatia to ml medvedn iea. although he was not a geologist sensl/ stricto he was persistent in his inco rrect opinion o r the archean age or the bosnian ophi olites (kispatic, 1917) and he argued with kat­ zer ( 1919) who correctly claimed that a gabbro occur­ ring in the area o f doboj was of mesozoic age. in the samc way kispatic d isputed the age o f the mt. fruska gom serpentinites wi th koch (1882) who class ified these rocks as belongi ng to the late cretaceous. fol low ing pil ar' s idea, gorjanovic-kram­ i3erger ( 1908) separated serpentinites on the first map of ml. medvednica. the serpentinite occurrence has a very important position because it is located along the boundary be twecn the "oriental land" and " eastern alpine branch". l ie was of the opinion that gabbro, dia­ base and melaphyre association, toge th er with upper cretaceous sedimentary co untry rocks, stretched [rom ml medvedni ca northeastward to mi. kalnik. koch (j904) and pollak (1914) published similar concep­ tually based idea on the mts. kalnik and medvenica. tn this way, the croat ian geoscientists la id the foun ­ dations of the knowledge of the dinarid ic ophiol ites in the earliest way of european geoscience. the work of mohorovic ic ( 1909) who was a geophys icist not undertaking research on ophiolites should also be rec­ ognized froltl thi s per iod . his study o r the pokupsko ea rthquake resulted in hi s discovery of the layered struct ure of the earth, and the bou nda ry be tween the c ru st and upper mantle was named ihe mohorov ic ic di scontinu ity in his honour. accord ing to modern geo­ dynamic ideas, rocks of the ophiolite association arc generated c lose to this di scontinuity. there fore, this was a contribution to global geological knowledge of great importance by croatian geoscience. 2,2, geosyncline period a ft er this f irst sllccessful period du ri ng the hislori­ cal investiga tion of the dinaridic ophiolites, ihe minera­ logica l-pe trol ogica l school of zagrcb university (under the leadership of tucan), was vcry active in the investi­ gation of crys talline rocks from the vardar zone. tajder ( j938) studied the dren 130ula ophiolites in mazedonia, which form the larges t fragment o r meso­ zoic ocean ic crust in europe. marie ( 1933) produced first comp lex geo logical-petrological study of ophio­ lites from the southeaslernmost parts of serbia, includ­ in g the first analytica l data for sedimentary rocks sur­ rounding the oph iolites. this period of the research ac ti vity on oph ioli tes was preceded by ve ry important pape rs publi shed by foreign geologists : ampferer & hammer ( 1917, 19 18) , hammer (1921) and pilger (1939, 194 1, j 942), who strongly influenced our subsequent investi ­ gations of the dinaddie ophiolites. these authors intro­ duced the teml " diabas-hornste in formation" compris­ ing ophiol ites and gene tically re lated sed imentary roc­ ks. this term was lised for the next fift y years. majer (1956) was the firs t o f our geosc ienti sti s who studied ophiolites from mt. sara, positioned in the area of the southeasternmost dinarides adjoining th e vardar zone. besides the first modern petrological data, he produced the first detailed geological map, and dis­ covered that these ophio lites, as distinguished frol11 the bosnian ones, occur in metamorphic rocks o r the kacanik· veles fo rmati on. he did not use at that time the pre vailing oph ilite hypo thes is in hi s geod ynamic interpretation. afterward s a ttenti on was focused on the bosni an oph iol ites . geoscienti sts were greatly interested in the age of th e diabashorn ste in form at ion as shown in numerous and bitter disc llss ions. however, the absurdi­ ty was the fac t that basic strati graphic data for these di sc llss ions had been mi s interpreted. t he dina ridic ophio lites including the surrounding gene tically related sedimentary rocks, a re in many areas spatially acco m­ pan ied by smaller or large r illasses of triass ic and pal aeozo ic carbonat e and cla sti c rocks , in which are also included middle triassic volcanics. the age of the diabas-t-lornstein form at ion as a whole was de ter­ mined on the basis of fossil findings in these ac tually a ll oc hthonous triass ie and palaeozoi c form ations. based on this criterion, the age of the diabasho rnste in formati on varied from o ne area to another from the permian up to the late triass ic, rarely up to the juras­ sic, depending on available palaeontological data from the allochthonous fo rmations. such an approach gave rise to additional mi sconceptions, and to the middle t riass ic volcanic-sedi ment ary formation s pos iti o ned outside the ophiolite zone were also g iven the name diabashornstcin formation (e,g, jovanovic , 1957, 1960; pamle, j961 ), step by step, during mapping over a comparativcly short period of tim e, new data were co llected which proved that two magmatic-sedim enta ry formati o ns ex isted: the middl e triass ic formatio n, gene ti cally re lated to the carbonatc pl atform, and a second forma­ tion gene ti cally rela ted to the ophi olites (ramie, 1963). at that time the supposed jurassic age of the ophio­ litcs was based mainly on data on the geological map or bosnia and hercegovina carried out by katzer ( 1906 and others). over scvera l map sheets he included ophio­ li tes in his " it" unit to which jurassic 10 lower cre ta­ ceous ages were assigncd. at approximately the same time, interes t was gener­ ated in ophiolites from the hrvatsko zagolje area of the northwestern dinarides. initial results furth er co mpli ­ cated the "ophiolite probl em". in the tvan sc iea and samoborska gora mts" herak (1956, 1960) discov176 n a " i k 'w~ " ii 45 0 nj r ' 10km 1n 2n ~"-i 4m~ 51 w"l 6 ,,~ fig. 2 structural -geological map of the krivaja-konjuh ul tramafic massif (pamic ci ai., 1977). geographical position of the kri­ vaja-konjuh massif is marked on the geological sketch-map of tile dinaridcs (f ig. 1). legend: i) ultramafics; 2) amphibolites; 3) gabbros; 4)coul1try rocks, mainly jurassic/early cretaceous graywackes and shales-ophiolite melange; 5) statistical dip of folialion; 6) fault. ered a close spatial connection between the typical upper cretaceous flysch , and the formation composed or sandstone with ophio lites, which is correlative in facies with analogous formations of the dinaridc ophi­ olite zone. he cautiously included the ophiolites in the uppe r cretaceous which had a grcat intluence on the cnsuing geological mappi ng of the ophioli te terrenes of north croatia. herak (1960, p. 117) concludcd thal: "new data obtained represent evidence that the dinar­ idie ophiolitc zone continues northwestward more fur­ ther than it was prcsumcd", obviously bearing in mind the then time prevailing geotectonic schemes of kober (1929) and petkovic (l958). also in this period kranjec (1969) described conformable diabase bodies in the palaeontologically documented upper cretaceous flysch of mi. majevica, in northeast bosnia whieh overl ie the dinaride ophio­ lite complex. 2.3. transitional period the geosyncline period preceded the elaboration of the basic geological map in whieh the dinaride ophio­ lite zone was also included. in late 1950 ' s and early 1960's, the mapping of the middle parts of the dinaride ophiolite zone in bosnia began. during this period some ideas were clarified and very important results obtained. 1) it was quite clear that ophiolite bodies wcre included in the oiabas-hornstei n formation which was idcntified with katzer's (1906) "it" unit composed mainly of sandstone and shale. 2) a unit was mapped which was composed mostly of radiolarite interlayered with shale and micrite with synsedimentary basalt. the unit had a large stratigraph­ ic span from the middle/late triassic to the early cregeologin croatica 50/2 taceous. in spite of the fact that radio larites are charac­ teristically associated wi th ophiolites (steinmann, 1926) this radiolarite fornlation had 110t been connected with ophiolites at this time. 3) under the influence of aubouin 's students (bla­ nchet, 1975 and others) the allochtonous character of the triassic rocks was discovered. those a re also very common as olis toliths in the diabas-hornstein forma­ tion. it than became quite c lear how the previous idea that these triassic formations wcre normal members of the the diabas-hornstein formation was incorrect. 4) mapping also included structural analyses of large ultramafic bodies. identifying kispatic's "allign­ ment", i.e. the foliation, it was discovered that internal structures of the ultramafic bodies were not com­ formable with the structures of the surrounding geneti­ cally related sediments. based on their obvious tectonic contact it was concluded that the ultramafics were intruded as solid bodies (fig. 2). it was further discov­ ered tha t larger ultramafic masses were thrust onto the surrounding sedimentary rocks of the diabas-hornstcin formation, and that associated gabbro and diabase bod­ ies are also in tectonic contact with the surrounding sediments. 5) it was noticcd that amphibolites, in some places with eclogites, occur along the marginal parts of ultra­ mafic massifs with com mon interlayering. this repre­ sented evidcnce for kispatlc's (1897) idea on the mutual close genetic relationship between the ultrama­ fic rocks and amphibolites. 6) it was also quite obvious that the interlayering of basalts with shales and graywackes of the diabas-horn­ stcin formation occurred at many outcrops. some of these new data were successfully published even in foreign journals, and reprcscnted the basis for the search for new solutions and more adcquate inter­ pretations amplify. on the basis of new structural and petrological data correlated with new geophysical pro­ specting data from recent oceans, it was concluded, 5-6 years before new ideas on plate tectonics appeared, that the dinaridic ultramafic bodies intruded as solid bodies (protrusions), and that they originated at deep parts of the lithosphere, i.e., the upper mantle (pamic, 1964; trubelja & pamic, 1965). in this transitional period, new data obtained in the early elaboration of the basic geological map of the bosnian part of the ophiolite zonc, clearly showed that the geosyncline concept was unable to explain the com­ plex probl em of ophiolite generation . ophiolite rese­ archers of the northwestern dinarides did not have such problems at that time because they only began about 10 years later with the mapping of their ophiolite terrenes. 2.4. plate tectonic period isacks et al. (1968) published their geophysical pioneer paper on plate tectonics which was soon fol­ lowed by many geological publications (e.g. dewey ramie: 111e development of croali;lil geoscience as reflected by the study of dinaridic ophiolites 177 & dird, 1970, and others). 11 seems [hat no single geo­ logical problem experienced such rcvolutionary cha­ nges in interpretation as did that or the orogenic ophio­ lites. in a few years several crucial papers (cole­ man, 1971, 1977; dewey, 1976; moores & jac­ kson , 1974 anci others) essent ially changed our con­ ceptions of ophiolites. the new ideas were accepted very quickly and after a few years the term "diabas-i-lornstein formation" had been forgotten. as sometimes happens in such decisive situations, it appeared a dangerous exaggeration with "new" ideas. in fact , in these first years, tendency was expressed that the complex problem of the dinaridic ophiolites would be covered by the term "melange". working on the californian ophiolites, hsue ( 1968) rccnvcred greenly's (1919) idea on [he "an­ kara melange" in turkey in order to emphasize the chaotic features of the ophiolite complexes. this mela­ nge idea was very quickly accepted for the dinaridie ophiolites. according to this, the dinaridic ophiolitic complex as a whol e was interpreted as a huge melange, i.e., the chaotic formation which originated at first by an olistostrome mechanism with subsequent processes or recyc ling, i.c. , [ce[onics (dimitrtjevic & dim!­ trijevic , 1973). based on these idcas, all ophioli[ie rocks including large ultramafic massifs with surfaces of 500i 000 km 2 were considercd to represcnt olis­ toliths included in the melange. 3. discussion the advent of plate tectonic theory generated a host oj" new ideas with the potcntial to significantly alter the basic approach to ophiolitic investigation. howevcr, by not entirely rejecting ideas concerning the chaotic fea ­ tures of ophiolites these teltenes have been continuous­ ly mapped, new data systematically collected and con­ s idered and interpreted according to new geodynamic ideas, i.e., plate tectonics. numerous papers have been published on ophiolites from different parts of the dinaridc ophioli[e zonc (bailic c[ a!., 1979; belak c[ a!., 1995; lanphere e[ a!., 1975; lugovic c[ a!., 1991; majer, 1978 , 1991; majer e[ a!., 1979; pam ic, 1982, 1993; herak, 1991, 1995; sikic e[ a!., 1979; simunic & simunic, 1979; simunic et a!., 1981; sparica, ]981; sparica e[ a!., 1979; susnjar & grimani, 1986; trub elja e[ a!., 1995; zupanic e[ a!., 198 1 and others) from which the followin g conclusions may be drawn: 1) ophiolitic rocks are spatially and genetically l"ciated to two differellt formation s which originated ill two dilterent environments. a) the radiolarite formation in which radiolarite prc­ dominates over shale, micrite and sy nsed imentary b<:lsall. this formation originated in the pelagic parts of the dinaridic tethys from the late triassic to the early cretaceous. b)the shale-graywacke formation, also with synsedi­ mentary basalts, which covers most of the dinaride ophiolite zone. normal profiles with "bed to bed" alternating shale, graywacke and basalt are only pre­ served ill somc areas. lithologically homogeneous teltenes composed only of graywacke, or shale, or basalt alone are rare. no characteristic fossils to date have been found in the graywacke and shale, but based on uncharacteristic microfoss il s found in rare interstrati[ied micrites, a jurassic age can be suggest­ ed. early palaeo floristic data suggest an early creta­ ccous age [or the sedimentary parts of the graywa­ ckes. however, the shale-graywacke formation is mainly chaotic and represented by melange. the graywackes arc included in a shaley-silty matrix in the form of flow-ball and slumps as well as larger or smaller frag­ ments of indegenous basalts. these arc associated with tectonically embedded erratic blocks of limestones, which originated in diffcrent environments from the middle triassic to the tithonian -valanginian. t-iow­ ever, the most common and characteristic arc tectoni ­ cally included fragments of ophiolites diabase, gabbro and serpent ized peridotite, the size of which ran ges from a few millimetres-centimetres to hu ge bodies reaching decaki!ometre in diametrc. consequently, in their completc development, the dinaridie ophiolites arc spatially associated with the shale-graywacke for­ mation. the opinion prevails thai the shale-graywacke for­ mation of the alpine-himalaya belt originated alo ng the active tethyan marg in . for the dinarides there are insufficient analytical data on the sedimentological fea­ lures of [he formation (tisljar, 1973; babic e[ a!. , 1979). when subduction processes began at the end of the late jurassic and the beginning of the early creta­ ceous, rocks of the mesozoic oceanic crust were empla­ ced in the shale-graywacke formation. the emplace­ ment (obduction) was accompanied by dismembering of the obducting oceanic crust and subseq uent sou th­ westward thrusting. 2) duc to this emplacement and the chaoti c charac­ ter of the shale-graywacke [ormation, rocks of the oceanic crust, i. e., the ophiolites, are preserved as tec­ tonic fragments regardless of size. the field relation ­ ships and geophysical prospecting data suggest that the largest ultramafic massifs, a few hundred kilometres in the surface area, represent sheets, up to 2000 m thick, which were thrust onto the shale-graywacke formation and the melange, respectively (fig. 2). isotope crystal­ li zat ion ages measured from ultramafics, mnphibolites and gabbro-diabases range between j89 and 136 ma which co rrespond to the lias to neocomian period s. these data, together with the aformentioned strati­ graph ic data indicate that the dinariclic oceanic crust was generated during the jurassic and lower parts of the cretaceous. such a conclusion fils with the global inter­ pretation of the alpine-himalayan belt. )"/x lieologla croalh.:a :juri, 3) the dinaridic ophiolitcs are in many areas acknowledgement unconformably overlain by conglomerate, breccia and lithic sandstone in which ophiolites and genetically the author is indebted to professors v. majer and related sedim entary rocks are redeposited. laterally, lj. babic [or the cri tical reading of the draft of the this formation is in some places interlayered with reef manuscript. limestones of tithonian-valanginian age, but in some other places the overstepping sequences are late juras­ sic to late cretaceous in age. 4) the dinaridic ophiolites are overlain by allo­ chthonous tri ass ic formations of the typical alpine develop ment , only loca lly with lias limestone, and palaeozoic semimctamorphic formations, i.e. the pan­ non ian nappe (miladinovic, 1974) or [he palaeo­ zoic-triass ic nappe (pamic & jurkovic , 1996) . stacki ng of the allochthonous masses was accompanied in some areas by greensc hi st faci es metamorphism which look plase 125-115 ma ago (belak e[ ai. , 1995). emplacement of these nappes was probably related to the final phascs of latc jurassic/early creta­ ceous obd uction processes. this conclus ion is support­ ed by the fact that the palaeozoic-triassic nappes arc unconformab ly overlain by lower cretaceous clastic rocks including ophiolites and genetically related sedi­ ments. 5) the dinaride ophiolite zone is bounded in the sout hwest by mesozoic clastic and carbonate sedimen­ tary rocks of the passive continental margin of the dinaridic tethys "flysh bosniaque" of the french geologis[s (aubouin e[ a i. , 1970). these formation s are jurassic and cretaceo us in age and thus penecon­ temporaneous with the generation of the dinaridi c oceanic crust. 6) the dinaride ophiolite zone as a whole is over­ lain north ward by formations of the late cretaeeous­ palaeogene fly sc h which are part ly preserved in the prosara, motaj ica and majev ica mts. of the northern­ most dinarides (the vardar zone sensu lalo). the late cretaceous-palaeogene fl ysch, which is synsed imenta­ rily intcrlayered with upper mantle basa lts and conli­ nental crust rh yolites, is in some places underlain by strongly tcctonized ophiolite melange ind icating that the evolution of ophiolites also continued through the late cretaceous. in the northern part , rocks of the late cretaceous­ palacogene flysch we re affected by alpine regional metamorphism rela ted to the main alpine deformatio­ nal event (the pyrennean phase). the metamorphism was accompani ed by synkinemati c granite plutonism whose sr-isochron age is 48 ma. all these crystalline rocks originated along the active continental margin of the dinaridic tethys represented by a magmatic arc and [rench, i.c., [he subduction zone (pamic, 1993). 4. references ampferer, o. & hammer, w. (1917): ers[er ber­ icht liber eine 1917 im auftrage und auf kosten der kaiserlichen akademie der wissenschaflen asge­ fiihrte geologische forsehungsreise in nw serbien. ­ si[zungs ber. akad. wi ss ., math. -nat. kl , 126/9. 679-701. ampferer, o. & hammer, w. ( 191 8) : erster ber­ icht libel' eine 1918 im auftrage und auf kosten der akademic der wissenschaften ausgefiihrte geologis­ che forschungsreise in wes t serbien.sitzungsber. akad. wiss., ma[h.-na1. ki., 172/8-9,635 -668. aubouin, j. , blanchet , r., cadet, j.p. , cel­ et, p. , charvet, j. , chorowicz, .i. , cousin, m. & rampnoux, j.p. (1970): essai sur la geolo­ gie des dinarides.bull soc. geol. france, 7, 12/6, 1060-1095. babic, lj., zupanic. j. & crnjakovic, m. (1 979): prepoznavanje dviju jedinica ullutar "klasti­ ta s ofiolitima" ivanscice i uloga magmatskog poja­ sa i aktivnog kontinelltalnog ruba pri njihovom postanku. zbornik radova iv. god isnj eg znan­ stvenog skupa sekcije za geokemiju jazu, 115124, stub. toplice. belak, m., pamic, j., kolar-jurkovsek , '1'., pecskay, z. & karan, d. (1995): alpinski regionalnometamorfni kompleks medvedni ce (sje­ verozapadna hrvat ska). 1. croatian geological congress (opatija, 1995), proceedings, 2, 71-74, zagreb. blanchet, r. (1975): de l' adri a[ iquc au bassin pannonique, esai d'un modele de chaine alpine.­ mem. soc. geol. france, 80,120,1 -172. coleman, rc. (197 1): pla[e [eclon ic emplaeemen[ of upper mantle peridotit es along continental edges.journ. geophys. rcseareh, 76,12 12-1222. coleman, r.c. (1977): ophioli[es.minerals and rocks, 12, springer verlag, berl in-heidelberg-new york, 229p. dewey, j. f. ( 1976): ophioli[e obduc[ ion. tectono­ physics, 31, 93-1 20. dewey, i.e & bird, j.m. (1970): moun[ain bells and the new global teetoni cs.joum. gcophys. research, 75 , 2625-2647. dimitrijevic, m.d. & dimitrijevrc, m.n. (1973): oli stostrome melange in the yugoslavian l\l1lli(;: "111t: development of croatian geoscience as reflected by the study of dinaridic ophiolites 179 dinaricles ancl late mesozoic plate tectonics.j. geology, 81, 328-340. gorjanovtc-kramberger, d. (1908): geologi­ jska prijegleclna karta kraljevine hrvatske-slavo­ nijc. tumac geologijskoj karti zagreb (zona 22, col. xiv).nakl. kralj. zemalj. vlade, odjel unutar. posloye, zagreb, 75 p. greenl y, e. (1919): the geology of anglesy.great britain oeol. surv. mem., 1, 980p. hammer, w. (1921): ergebnisse der geologischen forsehungsreise in westserbien. 1. die basischen tntrusivmassen in westserbiens. ii. die diabashorn­ stc inschichten.denkschr. akad. wisscnsch., ma­ th.-natur. klasse, 98, wicn. herak, m. (1956): geologija samoborskog goi]a.­ acta geol., 1,49-73, zagreb. herak, m. (1960): kreda s ofiolitima u iyanscici (sje­ verozapadna hryatska).acta geol., 2, 111 120, zagreb. herak, m. (1991): dinaridi mobilisticki osvrt na genezu i strukturu.acta geol., 21, 35-117, zagreb. herak, m. (1995): koneepeijski doseg geologije hrvatskc.i. croatian geological congress (opati­ ja, 1995), proceedings, i, 25-35, zagreb. hsue, j. (1968): principles of melanges and their bear­ ing on the franciscan-knoxwille paraclox.bull. geol. soc. america, 79, 1063-1074. isacks, b., oliver, j. & sykes, l.r. (1968): seis­ mology and the new global lectonics. journ. geo­ phys. research, 73, 5855-5899. .jov anovic, r. (1957): pregled razvoja mezozoika i neki novi poclaci za straligrafiju n r bih. ii kon ­ gres geo!oga jugoslav ije, 38-63, sarajevo. jovanovic, r. (1960): dijabaz-roinjacka formacija ii boslli i hercegovini.simpozij 0 problemima alp­ skog inicijalnog magmatizma, ref. it , p. 17, ilidza­ vares. katzer, f. (1906) : historijsko razvijanje i danasnje stanje geoloskog proucavanja bosne i hercegovine.­ olasll. zem<1lj. muzo bih, 16,417-440, sarajevo. katzer, f. (1919): das serpent in lind gabbro-vor­ koml1lcll von kostajnica bei doboj ill bosnien.­ glasn . hry. prirod. drllstva, 31,96-97, zagreb. k1spat1c, m. (1897): kristalinsko kamclljc serpen­ tillske zone u bosni.racl jugosl. akacl. znan. umjet­ nosti, 133, 95-231, zagreb. kispi\tic, m. (1899): nastavak bosanske serpentinske zone u t-trvalskoj.rad jugosl. akacl. znan. llmjet­ nosti, 139,44-73, zagreb. kispatic, m. (j917): angebjicher serpentin und oabbro-durbuch in der nachc von kostajnica bei doboj in bosnien.olasll. hrv. prirodosl. drustva, 29, 33-48, zagreb. kober, l. (1929): die grossgliederung der dinari­ den.cbl. miner. geol. palaent., 10, 425-437, stullgart. koch, a. (1882): gcologiai koez!emenyek a fruska­ garaol.focld. koezloeny, 10/12,257-269, buda­ pest. koch, f. (1904): serpcntinsko kamenje zagrebacke i kalnicke gore.nas!. vjesnik, 13/2,217-220, zag­ reb. kranjec, v. (1969): geoloska grada sireg tllzlanskog podrucja. pos. izdanja ins!. ruel. hem. tehll. istr<1z. , tlizla, 284p. lanphere, m., coleman, r., karamata, s. & pamic, j. (1975): age of amphibolites associated with alpine peridotitcs in the dinaride ophiolite zone, yugoslavia.earth plall. scie. letters, 26, 271 -276. lugovic, b., altherr, r., raczek, j. , hof­ mann, a.w. & majer, v. (1991): geochemistry of peridotites and mafic igneolls rocks from the ccntral dinaric ophiolite belt , yu goslavia.coil­ trib. mineral. petrol. , 106,210-216. majer, v. (1956): petrografija i petrogeneza uliraba­ zicnih stijena brezovice na sjevernoj strani sar pla­ nine.acta geol., 1,89-148, zagreb. majer, v. (1978): mezozojski magmatizam unutra­ slljih dinarida (odnosno ofiolitnc zone u podrucju pokuplja i banije) u hrvatskoj i njegovo pctrolosko i geolosko zilacenje.geol. vjesnik, 30/2, 669-709 . majer, v. (1993): ofiolitni kompleks banije s poku­ pljcm u hrvatskoj i pastireva u bosni.acta geol, 23, 39-84. majer, v., kreuser , y., harre, w., seidel, e., altherr, r. & okrusc1-1, m. (1979): petrology ancl geochronology of mctamorphic rocks from banija, yugoslavia.ophio!. symposium, 46-47, n icosia. maric, l. (1933). geolosko prolicayanje stare raske, prilog petrografiji stare raske.glasllik srp. kralj. akad., 158,78/1,143-189, beograd. moi-lorov.jcic, a. (1909): potres od 8 . oktobra 1909.god. izvj. zagreb. meteor. opserv. za god. 1904, 9/4, i, zagreb. miladinovic, m. (1974): tektonska gradja ,cvemih delova jugoslavenskih dinarida.oeo!. glasn ik , 7, 351-367, sarajevo. moores , e. & jackon, e.d . (1974): ophiolites and oceanic crust.nature, 250, 136-138. pamic, j. (1961): karakteristike illagillatskih stijena dijabaz-rozlljacke serije u okolici lablaniec i prozora (bosna i hercergovina).iii. kongres gcologa jugoslavije, 363-382, budva. pamic, j. (1963): osvrt na problem vulkanogeno-sedi­ mentnih formacija u dinaridima na podrucju bosne i hercegovine.geol. glasnik, 8, 5-27, sarajevo. pamic, j. (1964): magmatske i tektonske strukture u ultramafitima bosanskc serpentinske zone.poscb. izd. geo!. glasnika, 2, 3-108, sarajevo. pamic, j. (1982): some geological problcms of the dinaridie ophiolites and their assoeiations. earth evo!. scienccs, 2, 30-35. pamic, j. (1993): eoalpine to neoalpine magmatic and metamorphic processes in the northwestern varelar zone, the easternmost periadriatic zone and the sollthwestcrn pannonian basin.tectonophy­ sics, 226, 503-5 i 8. pamic, j. & jurkovic, j. (1996): geology of bos­ nia and hercegov ina. in: moores, e. & fair­ bridge, r.w. (cds.): encyclopedia of europcan and asian regional geology. chapman & i-jail, london-new york-to kyo-melbourne, 86-93. pamic, j., sunaric-pamic, 0., olunc, j. & an­ tlc, r. (1977): pctrografija i petrologija krivajsko­ konjuskog ofiolitnog kompleksa i njegove osnovne gcoloske karakteristike.acta geo!., 9, 39-135, zagreb. petkovic, k. (1958): neue erkentnissc tiber den bau del' dinariden.iahrb. geol. bundcsanst., [oj, [-24. pilar, gj . (1882): geoloska zapazanja u zapadnoj bosni. istrazivanja od 1879.rad jazu, 61,1-68, zagreb. pilger, a. (1939): der innerdinarische trog im profil von sarajevo.zeitrschr. deutschen geot. gesel­ schart , 91, 705-724. pilger, a. (l941): palaeogeographie und tektonik jugoslawiens zwischen del' una un dem ziatibor gebirge.n. jahrb. min. geo!. palaont. (b), 85, 383-462. pilger, a. (1942): die stellung des innerdinarischen troges im alpinen orogen.n. jahrb. min. geo!. paluon!. (b), 86, 163-188. poljak, j. (1914): iz gcologijc kalnickc gore.vijesti gco!. povj., 3/4, 93-100, zagreb. steinmann, g. (1926): die ophiolitisehen zonen in den mediterranen kellengebirge.14th intern. geol congr., 2, 637-677, madrid . sikic, k., basch, o. & simunic, a. (1979): osno­ vna geoloska karta sfrj 1: 100.000. tumac za list zagreb l33-80 (geology of zagreb sheet).ins!. gco!. islraz. zagreb ( 1972), sav. geo!. zavod, beo­ grad, 81 p. geologia c roullca :.u/2 simunic, an. & simunic, ai. (1979): litofacijesno rasc1anjivanje mezozojskih naslaga kalnickog gor­ ja.iv. goelisnji znanstvelli skup znanstvellog sav­ jeta za naftu jazu, 1978, 125-137, stubicke top­ lice. simunic, a., pikija, m., hecimovic, j. & simu­ nic, a. (l98 i): osnovna geoloska karta sfrj i: 100.000. tumac za list varaidin l33-69 (geology of varazdin sheet).geo!. zavod zagreb, say. geo!. zavod, beograd, 75p. sparica, m. (l981): mczozoik banije, korduna i dodirnog podrucja bosnc.pos. izdanjc "naftc", zagreb, 2451'. sparica, m., bencek, d. & magdalenic, z. (1979): facijelne karakteristike vulkanogeno-sedi­ mentnog kompleksa stijella podrucja abes-lasinja u baniji.iv. godisnji znanstveni skup znanstvenog savjeta za naftu jazu, 1978, 138-146, stubicke topliee. susnjar, m. & grim ani, j. (1986): strukturno-tek­ tonski oelnosi ofiolitskog pojasa banije.geol vjes­ nik,39, 109i 19. tajder, m. (1938): fiziografija, kelll ijski sastav i gencza gabroidnog masiva drcn-bou1a u juznoj srbiji.rad jazu, 263(82), i-54, zagreb. tisljar, j. (1973): kvantitavni petroloski studij scdi­ menata "fl isnc scrije" i jurskc vulkanogcno-sedi­ mcntnc formacijc borovickog potoka u sjcvcrnoj11 krilu velikog vare.skog antiklinorija.geol. glasnik, 17, 133-168, sarajevo. trubelja, f. & pamic, j. (l965): pelroloska studija planine ozren. acta geo!., 4, 265-314, zagreb. trubelja, f., marchig, v., burgati-i, k.p. & vujovic, z. (1995): origin of the jurassic tel­ hyan ophiolites in bosnia: a geochemical approach to tectonic sctting.geo!. croat., 48/1,49-66 . vukotinovic, lj. (1853): einige mitteilunge tiber das kalniker gebirgen in kroatien.lahrb. geo!. reichsan., 4/3, 550-552. zupanic, j. , babic, lj. & crnjakovic, m. (1981): bazenski klasti ti donje krede (ostree-forma­ cija) ivanscice u jugozapadnoj hrvatskoj.aeta geo!., 11 , 1-44, zagreb. manuscript receivcd april 14, 1997. revised manuscript accepted november jo, 1997. 01 babic.indd 1 � ab stra ct the palaeogene promina beds (pb), exposed in the dinaric coastal range, is about a 2km thick heterogeneous succession representing a late sedimentary fi ll of the north dalmatian foreland basin. the paper focuses on the middle part of the pb represented by a prominent transgressive unit. the study of this unit is based on fi eld mapping, logging and facies analysis, as well as the investigation of stratigraphic surfaces and facies successions. the unit extends for more than 63km, along the entire basin. deposition began transgressively over both alluvial deposits of the lower pb and karstifi ed basin basement. along its extent the studied unit may be represented either by stacked (highfrequency), marine transgressive-regressive cycles, by lacustrine deposits, mainly limestones, or by a single, marine limestone unit. an ideal transgressive-regressive cycle includes a transgressive segment of limestones, and a regressive segment of storm-wave dominated shelf to gravelly beachface (coarsening-upward) deposits. gravelly beaches are represented by several types. one of them included the steeply inclined, lower beachface which is situated below the intertidal zone. the cycles are separated by lower-rank discontinuity surfaces (fl ooding surfaces), while their two segments are separated by a lower-rank transgressive-regressive turnaround surface. lacustrine deposits originated due to a rise in groundwater induced by a sea-level rise basinwards. the deposition of a single limestone unit resulted from a transgressive onlap over uplifted, eocene and cretaceous carbonates of the basin basement. the end of the transgression is marked by condensation processes indicated by glauconite, skeletal debris, planktonic foraminifera and hardgrounds, and a major transgressive-regressive turnaround. the subsequent evolution is almost uniform along the entire extent of the studied unit, and includes shelf to delta and shelf to beach cycles of the highstand. the studied allostratigraphic unit is here given a formal name: the novigrad alloformation. keywords: transgressive-regressive cycles, transgressive limestones, gravelly beach, beachface sequence, condensation, novigrad alloformation, promina beds, dinarides laterally variable development of a basin-wide transgressive unit of the north dalmatian foreland basin (eocene, dinarides, croatia) � ljubomir babić1 and jožica zupanič2 1 institute of geology and paleontology, department of geology, faculty of science, university of zagreb, horvatovac 102a, 10000 zagreb, croatia; (ljubomir.babic@zg.htnet.hr) 2 institute of mineralogy and petrography, department of geology, faculty of science, university of zagreb, horvatovac 95, 10000 zagreb, croatia doi: 104154/gc.2012.01 geologia croatica 65/1 1–27 32 figs. zagreb 2012 geologia croaticageologia croatica 1. introduction an understanding of key stratigraphic surfaces and facies pattern in sedimentary units is fundamental for any attempt to improve the understanding of a basins history (wilgus et al., 1988; posamentier & allen, 1999; catuneanu, 2006). this is especially true for stratigraphic units of broad extent within a sedimentary basin. the identifi cation of such units is important for stratigraphic correlation, which is a basic prerequisite in the analysis of a sedimentary basin (miall, 2000). a widely-distributed transgressive unit of this type has been investigated in the sedimentary fi ll geologia croatica 65/1geologia croatica 2 of the palaeogene north dalmatian foreland basin, which is located within the dinaric coastal range. although the importance of this unit has been recognised previously, only partial descriptions have been provided (babić & zu panič, 2007; babić et al., 2010; zupanič & babić, 2011). based on fi eld mapping and logging, this paper describes the extent of the unit, and details of complex, laterally varying vertical successions encountered along its basin-wide extent. based on facies analysis, we interpret facies successions that represent carbonate platform settings, shelf to beachface environments, as well as lacustrine settings. specifi c features characterising both the onset and end of the unit, and relevant sequence-stratigraphic aspects, are discussed in particular. a description of high-frequency depositional cycles is also given. part of the paper deals with coarse-grained beach sequences, which are diffi cult to observe in present-day environments, but can be compared to examples described from the stratigraphic record (e.g. clifton, 1981; wright & walker, 1981; dupré, 1984; leithold & bourgeois, 1984; massari & parea, 1988; hart & plint, 1989). the studied unit is proposed as novigrad alloformation. 2. geological setting, outline of the stratigraphy and previous work the transgressive unit which is the subject of this paper, forms part of the approximately 3km thick sedimentary fi ll of the palaeogene north dalmatian foreland basin. the basin is situated within an imbricate and folded belt stretching along the outer dinarides (fig. 1). towards the ne, the belt is bound by larger dinaric thrust units. on its sw, adriatic side, it is bound by the foreland, which is a common foreland to both the dinarides and the apennines (fig. 1a). the imbricate-folded belt consists of cretaceous to eocene platform carbonates, eocene-oligocene foreland basin deposits (mainly clastics), minor neogene sediments, and quaternary deposits (reviews in majcen & korolija, 1973; mamužić, 1975; ivanović et al., 1976, 1978). during the major part of the mesozoic, the area represented a segment of the carbonate platforms that formed a major part of the future outer dinarides (vlahović et al., 2005; korbar, 2009). the propagation of tectonic deformation of the dinaric orogen towards the sw, caused the migration of foreland basins, and led to basin formation in the area of the present-day imbricate-folded belt during the middle eocene (e.g. ivanović et al., 1976; mamužić, 1975; for alternative dating see mikes et al. (2008) and appendix). this is an example of a well-known relationship by which the deformation and foreland basin migrate and develop together (beaumont, 1981; miall, 2000; allen & allen, 2005). the early basin evolution started with a forebulge stage refl ected in the subaerial exposure of cretaceous carbonates, and continued to develop through ramp limestone, hemipelagic and turbiditic stages of sinclair’s (1997) “underfi lled trinity” (babić & zupanič, 2008) until the middle eocene. subsequent evolution of the basin may be designated as a molasse stage corresponding to conditions when shortening slowed down and subsidence rate became outpaced by sedimentation rate, which results in shallowmarine and continental depositional settings (e.g. sinclair, 1997; miall, 2000). during this stage, the major part of the sediments deposited in present day n dalmatia, has commonly been designated as the promina beds (pb) (schubert, 1904, 1908; mamužić, 1971; ivanović et al., 1973, 1977), and dated as late lutetian to early oligocene (mamužić, 1975; ivanović et al., 1978; sakač et al., 1993). marinčić (1981) envisaged the deposition of the pb and fl ysch as laterally-equivalent facies, in proxifigure 1: a – location of the north dalmatian foreland basin in the dinarides, and the position of neighbouring, larger tectonic units. framed area is shown in 1b. b and c – position of the north dalmatian foreland basin within the imbricate and folded belt, which is bound by important thrust faults. b – simplifi ed after prelogović et al. (2003). framed basin area is shown in fig. 5. c – simplifi ed after korbar (2009). the cross-section covers a small, nw part of the present-day basin. babić and zupanič: laterally variable development of a basin-wide transgressive unit of the north dalmatian foreland basin... geologia croatica 3 mal and distal parts of the basin, respectively. it has also been proposed that the pb originated in a basin that was bounded by a precursor of the velebit fault to the ne, and an outer, uplifting structure to the sw (fig. 2; šikić, 1969). the basin was presumably open towards the nw, and besides the sediment supply from the orogen to the ne, there was nw palaeotransport along the se-nw oriented tectonic structures (babić et al., 1995). šikić (1969) envisaged a ne-directed migration of the promina basin, based on an overall, ne directed younging and onlap of the sedimentary succession, which were described by quitzow (1941). hence, the basin may have been formed and carried piggyback on a nappe, in front of a major thrust fault (or zone), while its outer fl ank may have been an anticline or an initial thrust fault located somewhere along the future outer side of the zadar archipelago (babić et al., 1995). a comparable tectonic situation has been envisaged by korbar (2009), who depicted the late eocene promina basin situated on top of a huge, complex nappe (fig. 3). while the entire pb are of late middle eocene to late eocene and possibly oligocene age (mamužić, 1971, 1975; ivanović et al., 1973, 1976, 1977, 1978), the transgressive unit described here is located within the late eocene interval of these authors. subdivisions of the pb, largely based on facies successions and sequence stratigraphy, have been proposed for specifi c parts of the basin and parts of the overall sedimentary succession (babić et al., 1995, 2010; mrinjek et al., 2005; babić & zupanič, 2007; mrinjek, 2008; mrinjek & pencinger, 2008; zupanič & babić, 2011). figure 2: hypothetical position of the present-day coverage of the north dalmatian foreland basin sediments in the late middle to late eocene. it was located in an inner basin, close to larger thrusts of the dinarides, the source area for the detritus delivered to the basin (arrows). inner and outer basins are separated by an uplifting structure (envisaged by šikić, 1969), which becomes less infl uential towards the nw, where there was a better connection between the two. smaller scale, nw–se trending, synsedimentary folds and thrust faults occurred within the inner basin (also documented here). not to scale. figure 4: stratigraphic position of the studied transgressive unit (tst, equivalent to middle promina beds) in the nw and se parts of the basin. compiled from babić & zupa nič (2007), babić et al. (2010) and zupanič & babić (2011). the meaning of the lacustrine unit marked by “?” is problematic. thickness of tst is exaggerated. figure 3: late eocene promina basin envisaged as piggy-back (wedge-top) basin(s) riding on a huge, complex nappe moving towards the adriatic foredeep. simplifi ed after korbar (2009). geologia croatica 65/1geologia croatica 4 however, only some of the previous descriptions include brief accounts of a transgressive unit represented by marine limestones and conglomerates, as well as minor lacustrine deposits, which have been proposed to represent a transgressive systems tract (babić & zupanič, 2007; babić et al., 2010; zupanič & babić, 2011) (fig. 4). further study of these sediments has revealed that they form more complex and laterally variable sedimentary successions than previously reported, and the relevant results are presented here. 3. methods we integrate the tracing and mapping of the studied transgressive unit and its bounding surfaces, fi eld study of facies and relevant bounding surfaces, logging and the analysis of more than 200 thin-sections. the thin-sections were mainly used for identifi cation of pedogenic features, distribution of benthic and planktonic foraminifera, occurrence of glauconite and lacustrine carbonates, as well as for confi rmation and the refi nement of relevant fi eld observations. our investigations also included parts of the underlying and overlying sediments. most of the studied sections include covered intervals and/or intervals where sedimentary features are poorly discernable and where only basic lithology is recognizable. this required investigation of an increased number of sections, as well as the collection of scattered data along the trace of the unit, together with the tracing of stratigraphic surfaces. mapping was performed at a 1:25000 scale and it covered the transgressive unit itself and parts of the underlying and overlying units. 4. description and interpretation of sedimentary successions the studied transgressive unit extends across the entire north dalmatian foreland basin (figs. 5, 6). the unit shows lateral differences, and there are also differences in the character of the underlying deposits and related bounding surface. this variability has been used to delineate seven types of sedimentary successions (t1s to t7s), going from the nw to the se. the following descriptions also involve neighbouring parts of the underlying and overlying units. the correlation of the studied successions is discussed later. 4.1. type 1 succession (t1s) – novigrad (figs. 6, 7) 4.1.1. description the exposures along the coast, close to novigrad (figs. 6, 7) start with middle eocene foraminiferal limestones, the top of which is marked by karstifi cation and local bauxite deposits. they are overlain by an approximately 90m thick unit of lime packstones, wackestones and rudstones which contain bivalves, gastropods, corallinaceans, smaller and larger benthic foraminifera (including fabiania, nummulites, discocyclina, and chapmanina), corals, bryozoans, echinoids and worms. these limestones have already been separated and mapped by schubert (1908, 1909), who designated them as the upper nummulite limestone (“unl” in fig. 7), or lithothamnium limestone, while sakač (1961) mapped the area in the same way. they are followed by roughly a 50m wide, covered interval which might hide a fault and an unknown part of the succession. the remaining part of the succession is organised cyclically, with ideal cycles consisting of limestone units and coarsening-upward (cu) units (figs. 7, 8). limestone units may start with a basal layer, which overlies an older cu unit. it is represented either by a conglomerate (< 10cm thick) containing benthic foraminifera, or by a lime packstone including granules and/or pebbles. both of these are followed by nodular lime wackestones, packstones and subordinate mudstones (fig. 9a). almost invariably, they contain smaller and larger benthic foraminifera, and may also include corallinaceans, bivalves, gastropods, echinoids, figure 5: geological map of the major part of the north dalmatian foreland basin (in grey) and its surroundings (partly simplifi ed after savezni geološki zavod, 1970). location of the studied transgressive unit, equivalent to the middle promina beds is indicated by thick, dark line. framed areas (a & b) are shown in fig. 6. the transgressive unit from novigrad to the krka river is strike-parallel and separates the fi elds of the lower pb to the sw from those of the upper pb to the ne. se of krka river and close to ne basin margin, the studied unit is involved in fold and fault structures which resulted in a complex distribution of the unit not entirely represented on the map. babić and zupanič: laterally variable development of a basin-wide transgressive unit of the north dalmatian foreland basin... geologia croatica 5 fi gu re 6 : g eo lo gi ca l m ap o f t he st ud ie d tr an sg re ss iv e un it an d pa rt s o f i ts b ou nd in g un its , w ith th e lo ca tio n of se ct io ns , i so la te d ou tc ro ps a nd p ho to gr ap hs . a a nd b a re e nl ar ge d se gm en ts o f t he m ap in f ig . 5 . s m al le r sh ift s al on g fa ul ts in vo lv in g th e tr an sg re ss iv e un it ar e no t i nc lu de d. t he y ha ve b ee n ob se rv ed c lo se to 2 b, in th e br uš ka a re a, w o f n un ić , s o f 2 i a nd c lo se to l iš nj ak . s e of k rk a ri ve r t he s tu di ed u ni t a ls o oc cu rs in o th er pl ac es , a si de fr om lo ca tio ns sh ow n on th e m ap , a s a re su lt of th e co m pl ex te ct on ic st ru ct ur e of th e ar ea . geologia croatica 65/1geologia croatica 6 bryozoans, and corals, as well as scattered pebbles and granules. the foraminifera include miliolids, and smaller rotaliids, discocyclina, asterigerina, nummulites, assilina, orbitolites, fabiania and heterostegina (fig. 9b). the uppermost ~0.4m portion of the uppermost limestone unit (fig. 7: above 89m) differs from all the other limestones. it is dominantly represented by mudstones and wackestones containing planktonic foraminifera and glauconite, along with larger foraminifera (discocyclina, operculina, spiroclypeus, heterostegina), smaller benthic foraminifera, echinoids and bryozoans. these limestones are also characterised by intense bioturbation, with common bored skeletons and abundant skeletal fragments. coarsening-upward units start with a thin mudstone or directly, with alternating laminae of mudstones, calcisiltites and calcarenites locally showing ripples (figs. 10a, 10b). the mudstones may contain smaller benthic foraminifera, and only the lowermost mudstone of one cu unit also contains a few planktonic foraminifera (fig. 7: 28m). this alternation is followed by thicker, up to 20cm thick, calcarenite beds and only minor mudstones. these calcarenites are erosionally-based, may display fl at laminae and rarely, wave ripples at the top (fig. 10c), and contain plant debris. vertical ophiomorpha, 25cm long shafts, are rare features. intercalations of contorted units which do not display preferred orientation may be present in this part. upwards, mudstones disappear, while the calcarenite beds become thicker and may be amalgamated. they are mostly parallel laminated and may include intervals with thicker laminae. wave ripples are rarely observed. some cu units include calcarenites which are bioturbated, display relics of horizontal laminae, wave ripples and possible hummocky cross-stratifi cation, and contain miliolids and rare nummulites. the subsequent, middle part of cu units consists of alternating calcarenites and small to large pebble conglomerates. the calcarenites are amalgamated, parallel laminated, while the conglomerates are erosionally based, thin, commonly one-pebble thick and discontinuous, and may laterally be replaced by scattered, individual pebbles. the middle part of the lowermost cu unit is thicker, more extensively developed and shows more details compared to most of the cu units (figs. 11 to 13). its lower part includes thin, partly discontinuous conglomerate beds based by irregularly undulating low-relief erosional surfaces (fig. 12). they may be replaced laterally by scattered, individual pebbles draping shallow scours. these conglomerate beds are quasi-horizontal (parallel to bounding calcarenites). upwards, conglomerate beds become thicker on average (up to 25cm thick), and more and more steeply inclined seawards, fi nally merging with the overlying, conglomerate clinoform figure 7: log of t1s (novigrad). fl, foraminiferal limestones (middle eocene). “unl”, upper nummulite limestone of schubert (1908, 1909). thick, framed t/r is the major transgressive-regressive turnaround surface which separates the studied transgressive unit (tst) and overlying regressive deposits of the hst succession. smaller t/r and fs are lower-rank transgressive/regressive turnaround surfaces and fl ooding surfaces, respectively. for further explanations see text. location in fig. 6. babić and zupanič: laterally variable development of a basin-wide transgressive unit of the north dalmatian foreland basin... geologia croatica 7 body. the conglomerates disappear within calcarenites offshore (fig. 11), while the calcarenites wedge out landwards due to the erosion of their upper parts (fig. 13a). conglomerates also form lenses, fi lling erosional depressions which are apparently oriented obliquely to the palaeo-shoreline, and also fi ll up to 15cm deep and up to one metre wide channels, oriented approximately e–w, i.e. approximately normal to the palaeo-shoreline (fig. 13b). convex up, dune-like bodies (fig. 11) also occur, as well as an example of cross-bedding directed offshore. very thin conglomerate beds and lenses may be poorly to well sorted. other conglomerates are commonly well sorted and mostly show bimodality, with modes in pebble and sand sizes, the latter representing the matrix. very rare clasts attain cobble size, up to 11cm in diameter. inclined conglomerate beds cut underlying calcarenites obliquely seawards up to 0.5m deep (fig. 13a). pebble imbrication (probable a-axis) dominantly dips onshore (fig. 12b) and rarely offshore. calcarenites are mostly amalgafigure 8: summary diagram presenting the model (complete) facies succession of the basic transgressive-regressive cycle, based on type 1 succession of the studied transgressive unit. 1 to 9 represents divisions of the model succession. for details see text and fig. 7. geologia croatica 65/1geologia croatica 8 mated, parallel laminated, rarely showing converging/diverging laminae at very low angles, and sometimes gently wavy lamination. they onlap inclined conglomerate beds, and close to the contact, they may be inclined landwards (fig. 13a). the upper part of cu units is represented by pebble conglomerate bodies with well marked clinoforms which include two parts. their lower part is up to 5m thick, develops from the segment described above by wedging out of calcarenites, while conglomerate bed attitudes assume steep inclinations (7° to 20°) (fig. 14a) towards wnw, w and wsw . there are also examples where the transition is sharp without interfi ngering. an angular basal contact is also observed. conglomerate beds are mostly 5 to 15cm thick, may be erosionally based and some of them pinch out down-slope, between bounding conglomerate beds. beds are usually well segregated, and may be very well to moderately sorted (fig. 14b). rare examples of poor sorting occur close to the base of the segment, in the case of a sharp transition (angular contact) from the underlying segment of the cu unit. most conglomerates are bimodal with modes in pebble and sand grades, the latter representing the matrix. the pebble imbrication almost invariably dips onshore, and a few observations revealed that a-axes are imbricate. offshore dipping imbrication is exceptional and very restricted laterally. only a single intercalation of parallel laminated calcarenite has been found in some conglomerate bodies. the transition to the upper part of the clinoforms seems (not clearly observed) to be achieved by a gradual reduction of bed inclination. in some cases, the transition is marked by thicker beds of poorly figure 9: t1s. example of fossiliferous limestone from the transgre ssive segments of a transgressive-regressive (t-r) cycle. 22.5–23m in fig. 7. a – typical appearance of nodular, bioturbated limestones. hammer = 32cm. b – thin-section of a lime wackestone to packstone: largest constituents (from left to right) are fabiania, agglutinating foraminifer, bryozoan and nummulites. figure 10: t1s. examples of the lower part of the regressive (cu) segment of t-r cycles. a – basal part of the regressive mudstone (light) overlies co ral bushes of the top of a transgressive limestone unit. the outcrop surface is almost parallel to bedding. this contact surface separates lower, transgressive and upper, regressive segments of a basic depositional cycle, a part of the studied transgressive unit. 28m in fig. 7. lens cap = 4.4cm. b – alternating mudstones and thin calcisiltites and calcarenites occurring closely above a. arrows point to two current ripples. lens cap = 4.4cm. 29m in fig. 7. c – “interference” ripples in calcarenites of a cu unit. road cut, close to section 1 (fig. 6). hammer = 32cm. babić and zupanič: laterally variable development of a basin-wide transgressive unit of the north dalmatian foreland basin... geologia croatica 9 type 1 succession (t1s) is fi rst overlain by mudstones containing rare, smaller benthic and planktonic foraminifera, very rare molluscs, and common plant remains. the mudstones quickly become intercalated with sharply based, thin, laminated calcarenites (fig. 15). sorted conglomerates. the upper part of clinostratifi ed bodies is mainly formed by sub-horizontal and gently inclined, dm-thick sets of thin conglomerate beds which may be bound by low angle, commonly fl at, erosional surfaces (fig. 14c). beds are mostly well segregated, on average thinner, and the conglomerates are well to very well sorted and on average fi ner-grained compared to the steeply inclined part of the body. rarely observed imbrication is offshore and onshore, and, an offshore dipping b-axis imbrication has been observed in only one case. a conglomerate bed is covered by symmetrical ripples, sinusoidal in outline, with wavelength of 23cm which are draped by calcarenite (fig. 7: 10.25m). this part of the clinoforms may include landward directed, low-angle sets of conglomerates. there are also minor, thin intercalations of parallel laminated and/or low-angle laminated calcarenites which either pinch out landwards or form lenses due to the erosion of their upper parts. examples of partial cycles include the alternation of limestone units and lower parts of cu units (e.g. 46–56.6m in fig. 7), and probable repetitions of lower-to-upper clinoform facies. figure 11: t1s: a part of the lowermost cu unit. in the lower part there are amalgamated, parallel laminated calcarenites of the shoreface. upwards, they become intercalated with thin, erosively based conglomerates which may be discontinuous, one-pebble thick and pinch out seawards (left). a dune-like conglomerate feature is seen in the middle right. in the uppermost left, there are conglomerates of the lower beachface. the wall surface is approximately normal to the inferred palaeo shoreline, land to right. 5.4–7.5m in fig. 7. figure 12: t1s. details of inferred upper shoreface deposits of the lowermost cu unit. 5.5–6.2m in fig. 7. a – even, locally wavy and low-angle laminated calcarenites include erosively based conglomerate intercalations. the upper one includes a small, channel-like scour. the outcrop surface is approximately normal to the palaeo-shoreline, land to right. pencil = 14cm. b – erosively based, imbricate conglomerate and even laminated calcarenites of the upper shoreface. imbrication in the conglomerate is dipping toward the right (landwards). note the bimodal character of the conglomerate (modes in pebble and sand sizes). above these deposits there is a thin conglomerate lens and isolated, smaller pebbles. lens cap = 4.4cm. c – small, gravel-fi lled depression (channel or gutter cast), scoured in evenly laminated shoreface calcarenites, and possibly oriented diagonally to the palaeo-shoreline. a few isolated pebbles above it may have been brought in at the very beginning of the post-storm recovery, from the beachface. section is approximately normal to the palaeo-shoreline, land to right. lens cap = 4.4cm. geologia croatica 65/1geologia croatica 10 figure 14: t1s. a – even bedded and bioturbated shoreface calcarenites, in the foreground (lower part of the photo), locally containing thin conglomerate lenses, (not visible here) are overlain by steeply seaward inclined conglomerates of the lower beachface. hammer = 32cm. 37–41m in fig. 7. b – dominantly well segregated, well sorted, pebble conglomerates of the lower beachface. note the dominant bimodality (pebbles & sand), and partial openwork in the bed just above lens cap (= 4.4cm). 40m in fig. 7. c – two sets of thin bedded, well sorted conglomerates inclined at low angles in diff erent directions, and inferred to indicate the upper beachface. horizontal segment of the rule is 22cm long. impression of diff erent bedding attitudes is accentuated by the varied orientation of outcrop surfaces. section is approximately normal to palaeo-shoreline, land to right. about 18m in fig. 7. figure 15: t1s. alternating calcarenites (dark) and mudstones (light), several metres above the major transgressive-regressive turnaround surface in fig. 7. the thickest calcarenite is parallel laminated in the lower part and ripple laminated above, while other calcarenites are ripple laminated. scale in cm. figure 13: t1s. calcarenites and conglomerates of the inferred upper shoreface. about 6.5m in fig. 7. a – calcarenites are mostly parallel laminated, and locally show converging/diverging laminae. toward the right (landward) they onlap a lower, inversely graded conglomerate bed (largest clast is 7cm in diameter), which obliquely and irregularly cuts underlying calcarenites. both the one-pebble thick conglomerate lens and conglomerates in the upper left cut underlying calcarenites in a similar way. b – two gravel-fi lled channels scoured in upper shoreface calcarenites, (the right part of the lower one and the left part of the upper one are visible). section approximately parallel to the palaeo-shoreline, the sea is in the direction of view. scale in cm. babić and zupanič: laterally variable development of a basin-wide transgressive unit of the north dalmatian foreland basin... geologia croatica 11 4.1.2. interpretation deposition of the “upper nummulite limestone” unit directly above the karstifi ed middle eocene foraminiferal lime stones and bauxite, refl ects a transgression of a shallow sea over an older limestone basement. the covered interval separating this unit and the remaining succession, as well as related, possible tectonic reduction, suggest that this unit might be older than the successions dealt with here, and will not be discussed further. a complete (ideal) depositional cycle (fig. 8) based on the succession at type section 1 starts with a foraminiferabearing conglomerate or clast-bearing lime packstone of the basal layer, which refl ects marine erosion, i.e. ravinement, and reworking of former shoreline gravels (discussed below). the basal layer therefore represents a marine transgressive lag. reworking of gravel by storms continued during deposition of the limestone unit which follows and resulted in the presence of granules and pebbles embedded in limestones even more than a metre above their base, indicating a lateral occurrence of gravels which were being eroded. diverse shallowmarine biota in limestones, including larger foraminifera, indicates well aerated, carbonate platform settings. coarsening-upwards units refl ect progradation of coastal settings. some cu units start with a thin mudstone refl ecting hemipelagic deposition on an outer shelf. the majority of cu units start with heterogeneous deposits of alternating thin mudstones, calcisiltites and calcarenites, the features of which suggest deposition in an offshore transition zone. contorted intercalations may have resulted from seismic shocks, considering the non-preferred orientation of deformations. the overlying, calcarenite-dominated part may refl ect waning storm processes in the lower shoreface. ophiomorpha burrows are consistent with rapid deposition. the above interpretation is in accordance with an overall shallowing-upward trend which is refl ected in the upward disappearance of mudstones, deposition of medium and coarse-grained calcarenites, and common upper plane bed lamination, which recorded high-energy, storm related processes. these processes must have operated more intensely and more frequently than before, thus suggesting a comparatively shallower part of the shoreface (fig. 8). rare wave ripples could represent a fair-weather record which was otherwise mostly obliterated by strong, storm related fl ows. bioturbated calcarenites with benthic foraminifera and relics of horizontal laminae, wave ripples and possible hummocky cross-stratifi cation may also be ascribed to processes in the shoreface zone, where fair-weather intervals permitted colonization by benthic organisms, and storms did not completely remove or rework the resultant sediments. the overlying, alternating conglomerates and calcarenites represent the progradation of an upper shoreface, partly based on their position between inferred shoreface deposits and lower beachface sediments (discussed below), and partly based on their own features (fig. 8). prominent erosional surfaces must have been generated by vigorous fl ows during the peaks of severe storms which removed much sediment from this zone. they also eroded sands from an outer part of the shoreface (amalgamation in the lower part of the cu), as well as the beachface gravels (discussed below). gravel taken from the beachface was transferred and redeposited onto irregular, seaward inclined to quasi-horizontal, erosional surfaces. alternatively, some thin gravel beds and lenses may have originated as a post-storm lag (clifton, 1981), by winnowing of the fi ner fraction from already emplaced sediment by poststorm swell waves. the imbrication features suggest strong seaward fl owing currents and related, rather dense gravel fl ows, additionally infl uenced by gravitational force (a-axis imbrication) and locally, by waves (bipolar imbrication). these processes were related to rip current activity responsible for both the strong erosion and grav el deposition. the gravel may have mostly been deposited in rip-channels directed perpendicularly and obliquely to the shoreface slope, and some of them in “gutters”. some thin gravel stripes might represent small, thin splays deposited at channel mouths. some discontinuous, shallow erosional depressions might have also represented troughs of longshore fl ows induced by strong cell circulation. narrow, sharp erosional scours might have originated by vortexes generated at the interference of seaward and oscillatory fl ows. the processes discussed above, therefore, mostly operated within a dissipative domain of the nearshore during peak storm conditions. similar deposits and related processes including storm-related erosion and strong, seaward directed fl ows in the shoreface, have been described from sedimentary formations of different ages (dupré, 1984; leithold & bourgeois, 1984; bourgeois & leith old, 1984; massari & parea, 1988; hart & plint, 1995). namely, gravelly coasts which are basically refl ective may become dissipative or include a dissipative domain during severe storms (massari & parea, 1988, with references). low-angle and convex upward lamination in calcarenites may refl ect a growth of low sand bars located between scours. in general, the overall pattern and geometry of conglomerates and calcarenites are suggestive of lateral and vertical movements of the system of bars and channels, as a result of oblique wave incidence (massari & parea, 1988). the climbing of inferred arenite bars over the beach slope represents a welding of bars to the beachface, i.e. the end of dissipative conditions and a return to a refl ective situation and a recovery stage (op. cit.). it may also be mentioned that the interval of alternating conglomerates and calcarenites does not contain any record of fair-weather conditions, which emphasises the importance of storm-wave domination over the sedimentation. in contrast to the lowermost cu unit discussed above, higher cu units show faster evolution of the alternation interval, where only one or a few thin conglomerate beds and lenses might indicate slightly less infl uential dissipative conditions compared to the fi rst cu unit. shoreface settings subsequently developed into gravelly beachface settings represented by conglomerate bodies of the upper part of cu units. the term “beachface” is here used following bourgeois & leithold (1984) and massari & parea (1988) to refer to the whole sloping face of the beach, down to the landward boundary of the shoreface. the steeply inclined lower part of conglomerate bodies and gently inclined to sub-horizontal upper conglomerates, geologia croatica 65/1geologia croatica 12 fi gu re 1 6: l og s of t 2s , p rid ra ga –b og oč in . t he s tu di ed tr an sg re ss iv e un it is u nd er la in b y al lu vi al d ep os its , a nd o ve rla in b y re gr es si ve d ep os its (h ig hs ta nd ). ts , t ra ns gr es si ve s ur fa ce . t hi ck , f ra m ed t /r is th e m aj or tr an sgr es si ve -r eg re ss iv e tu rn ar ou nd su rf ac e. s m al le r t /r sy m bo ls a nd fs a re lo w er -r an k tr an sg re ss iv e/ re gr es si ve tu rn ar ou nd su rf ac e an d fl o od in g su rf ac e, re sp ec tiv el y. d at um is th e m aj or tr an sg re ss iv ere gr es si ve tu rn ar ou nd su rf ac e. f or d et ai ls se e te xt . l oc at io n in f ig . 6 . babić and zupanič: laterally variable development of a basin-wide transgressive unit of the north dalmatian foreland basin... geologia croatica 13 closely resemble lower and upper beachface gravel facies respectively, described by massari & parea (1988) from the apenninic pleistocene, italy. as discussed by these authors, erosional truncations may have formed during the peaks of storms, while their lower beachface gravels accumulated in the declining stages of high-energy events when the beachface profi le tends to be restored. highly dominant, onshore dipping a-axis imbrication, refl ects a signifi cant infl uence of gravitational force superimposed on backwash. poorly sorted conglomerates locally observed at the base of clinoforms, may be explained by deposition from debris fl ows which originated by mixing of grain populations from several parts of the beachface, possibly related to the action of the most severe incoming waves. poorly sorted conglomerates at the transition from the lower to upper beachface, might represent step-like features of coarse-grained, refl ective beaches, which are produced by the interaction of breaking waves and backwash, which could have brought together particles from different zones, including the upper shoreface, lower beachface and berms (massari & parea, 1988). the depth to the bottom of the beachface might be estimated using the thickness of the lower beachface conglomerates that can attain 5m in thickness. flat and gently inclined erosional surfaces in the upper part of the clinoform bodies, are regarded as refl ecting the action of steep waves in a foreshore during storms, while deposition of sub-horizontal to gently inclined, thin bedded sets of well-sorted conglomerates above the erosional surfaces, may result from low-steepness waves during the early recovery period (cf. massari & parea, 1988). wave ripples on top of a conglomerate bed could have been produced during the recovery stage or a minor storm. onshore directed cross-beds were possibly deposited by swell, either as landward migrating bars or by swash washover in the back-beach area, but also in a beachtransverse channel, incised during a storm (op. cit.). calcarenite intercalations represent erosional relics of sandy foreshore settings which were active during “fair-weather” conditions the record of which has otherwise been mostly destroyed. as no indications of tidal processes have been found, the tidal range may be considered very small. the facies succession of an ideal (complete) cycle therefore includes a transgressive segment characterised by carbonate platform settings (limestone unit) and a regressive segment which resulted from deposition within shelf to beachface settings (cu units) (fig. 8). the two segments are separated by a discontinuity surface refl ecting the change from transgressive to regressive depositional trends. the cycles are bounded by discontinuities in sedimentation which may be considered as fl ooding surfaces of the sequence-stratigraphic classifi cation which is supported by the relatively simple internal organisation of the cycles, as well as their stacking within a larger depositional unit. hence, they represent the basic building units of a higher-rank unit, (sequence stratigraphy and related terminology are also discussed in section 5.). the end of deposition of the uppermost limestone unit, which is equivalent to the depositional end of t1s, is specifi cally characterised by a decrease in biogenic production and sedimentation rates, i.e. condensation and deepening. it is indicated by the appearance of planktonic foraminifera, autochthonous glauconite, increased bioturbation intensity and organic boring, and inferred scavenger activity resulting in frequent skeletal fragments (review in flügel, 2004). larger foraminifera in these limestones suggest that the area still remained within the shelf realm. t1s is overlain by a coarsening-upward succession starting with outer shelf mudstones and alternating calcarenites and mudstones. they represent the lowermost part of shelf to delta and shelf to beach cycles of the highstand tract which extends across the entire basin (babić & zupanič, 2007; babić et al., 2010; zupanič & babić, 2011). 4.2. type 2 succession (t2s) – from pridraga to bogočin: 2a–2j (figs. 6, 16) 4.2.1. description this type of facies succession characterises a 40km long stretch of the studied transgressive unit (figs. 6, 16, 17). for the most part it is poorly exposed and only incomplete sections are found here and there. figure 17: t2s at kolarna village (section 2g in figs. 6 and 16). below the transgressive surface (framed ts) there are conglomerate-dominated alluvial deposits. a subsequent transgressive unit (12m thick), ends at a major transgressive-regressive turnaround surface (framed t/r) which is fi rst overlain by basal mudstones of the regressive succession. geologia croatica 65/1geologia croatica 14 the type 2 succession (t2s) is underlain by alluvial sediments represented by two main facies associations. the fi rst one has been described as consisting of laterally extensive, sheet-like bodies of massive, horizontally bedded to gently inclined, and locally cross-bedded conglomerates, which include intercalations and lenses of laminated calcarenites, and are interpreted as representing deposits of braided channel belts (babić & zupanič, 2007; babić et al., 2010). the second facies association includes horizontally laminated, cross-bedded and current-ripple laminated calcarenites and mudstones, which commonly show pedogenic features and have been considered to refl ect deposition on fl oodplains. a type 2 succession resembles t1s in that it consists of limestone units and cu units, and in the character of the majority of its facies types. features of the basal contact vary with the type of underlying alluvial facies (figs. 18, 19). in the case of fl oodplain mudstones, their uppermost several centimetres, which show rhizocretions, nodular fabric and/or mottling and fenestrae, also include organic burrows fi lled with marine fossils. clasts of these mudstones may be found above the contact, in overlying marine, fossiliferous limestone. in the case of alluvial conglomerates, there is either a less than 8cm (possibly < 0.8m) thick basal conglomerate layer with marine fossils in muddy to calcarenitic matrix (e.g. 2e, 2g, 2h in fig. 6), or directly, marine, fossiliferous limestones which may contain granules and/or pebbles. the clasts may display borings by probable lithophagids. the basal limestone unit is present all along the extent of t2s, however, its thickness varies from several cm to 2m. the uppermost limestone unit extends along the entire stretch of t2s (fig. 16) with a thickness varying from less than 2cm (2e in fig. 6) to 10m. at some localities, there are intermediate, thin limestone units which are diffi cult to correlate and might belong to one or even two limestone horizons of unknown lateral extent. limestones are poorly bedded, commonly nodular, bioturbated foraminiferal lime packstones and wackestones, and minor mudstones (fig. 20). among the foraminifera, the most common include miliolids, other smaller benthic forms, discocyclina and nummulites. there are also fabiania, operculina, asterigerina, orbitolites, heterostegina, acervulinids, and less common sphaerogypsina, pellatispira, amphistegina and chapmanina. other constituents include corallinaceans, bivalves, gastropods, echinoids, bryozoans and corals, as well as scattered pebbles and granules in the lower part. schubert (1904, 1909) and šikić (1969) reported on larger foraminifera, gastropods, bivalves and echinoids from several locations corresponding to the t2s. it should be noted that quitzow (1941) mentioned a “transgressive breccia” which he observed in the area between localities 2h and 2i in fig. 6. according to this author, the breccia overlies conglomerates, consists of bivalves, gastropods and corals, and is overlain by mudstones. his conglomerates correspond to the top part of the alluvium, and the “breccia” probably belongs to the basal limestones of the studied transgressive unit. figure 18: along the stretch of t2s, the transgressive surface is represented by two types of contacts between the alluvial unit and overlying carbonate platform limestones of the transgressive unit. left: fl oodplain mudstones with organic burrows and fractures fi lled with marine limestone are overlain by marine limestone including fl oodplain mudstone clasts at the base. right: channel-belt, stream-fl ow conglomerates are fi rst overlain by a basal conglomerate layer containing bored pebbles and foraminifera in the matrix (laterally: limestone rich in granules and/or pebbles), and subsequently, by marine limestones. figure 19: t2s. two types of the contact encountered along the basal transgressive surface (ts) of t2s. a – the surface of the fl oodplain mudstone (light) is the top surface of the alluvial unit, and at the same time the major transgressive surface of the studied transgressive unit. the mudstone (seen in plan view) shows burrows infi lled by marine, skeletal packstones including pebbles and granules. the surface is overlain by limestones of the transgressive unit (not shown in this fi gure). coin = 1.9cm. location in fig. 6. b – thin-section of basal conglomerate layer which contains foraminifera in the matrix. section 2e in figs. 6 and 16. babić and zupanič: laterally variable development of a basin-wide transgressive unit of the north dalmatian foreland basin... geologia croatica 15 as in t1s, the uppermost 0.5m thick portion of the latest limestone unit, equivalent to the top portion of the entire t2s, differs from other limestones by its content of planktonic foraminifera and glauconite, the dominance of discocyclina among benthic foraminifera and the common occurrence of bored and fragmented skeletal remains (figs. 21a, 21b). this part also includes one or two prominent, irregular bedding plains (fig. 21c) which may display dense organic burrowing. coarsening-upward units are poorly exposed, and only parts of them may be recognised in several sections and isolated outcrops. their lower part includes calcarenites with rarely recognisable parallel lamination, hummocky crossstratifi cation, wave ripples (?), current ripple lamination, as well as cross-beds. they may be rich in plant debris. some calcarenites are bioturbated and contain benthic foraminifera; commonly miliolids and sometimes nummulites. this lower part of the cu units may also contain thin conglomerate intercalations which sometimes display cross-bedding and may also contain foraminifera. a unique, 40cm thick intercalation of a bivalve rudstone with sparse benthic foraminifera was observed close to section 2g (fig. 6). the upper part of a cu unit (2g in figs. 6, 16) includes a conglomerate clinoform body comparable to but slightly different from those in t1s. its wsw part consists of beds inclined 15° to 18° towards the sw, which tangentially join their base where they interfi nger with the underlying calfigure 20: t2s. a – thin, irregular bedding in basal fossiliferous limestone unit. section 2e in figs. 6 and 16. hammer = 32cm. b and c: thin-sections of fossiliferous limestones. section 2i in figs. 6 and 16. in b: discocyclina, heterostegina, operculina and other fossils. in c: corallinaceans and sphaerogypsina. figure 21: t2s. condensation features. a – thin-section showing fragmented skeletal remains (mainly foraminifera), inferred to have been produced by scavengers as a consequence of decreased sedimentation rates close to maximum transgression. b – borings in foraminifera may contain mudstone (m) and/or glauconite (g). a and b: section 2i in figs. 6 and 16. c – bioturbated hardground surface at the top of the transgressive unit (tst). section 2b in figs. 6 and 16. geologia croatica 65/1geologia croatica 16 carenites. the ene part of the body includes tangentially based, ne inclined (12° to 20°) conglomerates, as well as those with sw and wnw directed dips (inclination up to 18°) (fig. 22). the conglomerates are well defi ned, oneor a few clast-thick, well to moderately sorted and consist of pebbles and rarely granules. the uppermost part of the body consists of horizontal to sub-horizontal conglomerate beds which locally include erosionally based dm-thick sets of thin, well-sorted conglomerates. in a few other sections there are poorly exposed conglomerate intervals (e.g. 2e, 2f; figs. 6, 16), which consist either of (a) horizontal to sub-horizontal and gently inclined, thin, well to poorly sorted, pebbly and locally granule conglomerates, locally comprising foraminifera in their matrix or (b) erosionally based, thin sets of gently inclined, thin, well sorted, pebble and minor granule conglomerate beds. both of these conglomerate types locally include thin calcarenite intercalations. at one location (sw of donja bruška village, fig. 6), approximately in the middle of the transgressive unit there is a thin bed of lime wackestone/mudstone containing characean gyrogonites which overlie a poorly exposed conglomerate body. the type 2 succession is fi rst overlain by mudstones containing rare smaller benthic and planktonic foraminifera (fig. 23a), rare molluscs, and common plant remains including leaves . a tree trunk or branch was also found in these mudstones (fig. 23b). shortly above, the mudstones are intercalated with thin calcarenites (fig. 23c). the fi rst intercalations in the mudstones may also be represented by thin foraminiferal packstones to wackestones (locality 2b in figs. 6, 16). 4.2.2. interpretation the deposition of t2s was initiated after a marine transgression of alluvial sediments. the transgression was accompanied by erosion (ravinement), and deposition of reworked clasts and marine fossils, as well as by the installation of carbonate platform settings. limestone units refl ect similar conditions to those of t1s, based on almost identical features. similarity between t1s and t2s also exists in the condensed sedimentation, deepening and more open conditions at the end of the youngest limestone unit, as indicated by the appearance of glauconite, planktonic foraminifera, abundant bored and fragmented skeletal remains, as well as prominent bedding planes representing hardgrounds which refl ect seafl oor cementation and sedimentary omission (review in flügel, 2004). coarsening-upward units were produced by prograding coastal systems. their lower parts, dominated by calcarenites which locally display parallel lamination, current-ripple lamination, hummocky cross-stratifi cation and possible wave ripples, and may contain benthic foraminifera, recorded the infl uence of waves and storms in the shoreface zone. crossbedded calcarenites as well as the intercalation of a crossbedded conglomerate, might have resulted from the migration of bars across the shoreface which may refl ect dissipative conditions during major storms (e.g. bourgeois & leithold, 1984), in contrast to prevailing less energetic conditions. the unique bivalve rudstone bed within the inferred shoreface deposits may also have originated by storm processes or possibly, by tsunami waves. clinoform conglomerates represent prograding lower and upper beachface settings as discussed in section 4.1. associated, onshore prograding conglomerates may have been deposited by the swell either as landward migrating bars, as swash washover in the backbeach area, or as the infi ll of a beach-transverse channel incised in the upper beachface during storms (or by a stream) (massari & parea, 1988). however, a steep gravelly beachface does not seem to have been common on the t2s coasts. another gravelly type of coast generated (a) a succession of horizontal to sub-horfigure 22: t2s. landward (ne), steeply inclined conglomerates, possibly representing a fi ll of a channel incised in the beachface during a major storm. gently inclined fl ooding surface above the conglomerate body is poorly visible. the same conglomerate body is laterally represented by seaward inclined conglomerates. for details see text. close to section 2g in fig. 6 and 16. hammer (in the middle of the photo) = 32cm. figure 23: t2s. lower part of the regressive succession overlying the studied transgressive unit. a – mudstones with rare planktonic foraminifera occurring immediately above a major transgressive-regressive turnaround surface. section 2g in figs. 6 and 16. b – imprint of a piece of tree trunk or branch in mudstones containing common plant material. close to section 2i in figs. 6 and 16. c – alternating mudstones (light) and calcarenites (grey), about 7m above the top of the studied transgressive unit. calcarenites may change their thickness laterally over small distances and pinch out. hammer = 32cm. close to section 2c in figs. 6 and 16. babić and zupanič: laterally variable development of a basin-wide transgressive unit of the north dalmatian foreland basin... geologia croatica 17 izontal and gently inclined conglomerates, locally comprising foraminifera, which might represent small-scale cycles resulting from short transgressive and regressive episodes, possibly related to changing rates of sediment supply. a partly similar situation has been described by siggerud et al. (2000). still another type of coast was characterised by (b) erosionally based thin sets of sub-horizontal to gently inclined, well sorted conglomerates, directly neighbouring shoreface sands without an intermediate steep beachface. such conglomerates typically originate in the foreshore zone (review in nemec & steel, 1984), and are otherwise identical to the upper beachface conglomerates described above from t1s. in comparison to the typical beachface characterising t1s (figs. 7, 8) and probably occurring in section 2g (fig. 16), the majority of cu successions in t2s developed by coastal progradation where a steep beachface segment was absent. generally, there were two types of coasts which were generated during and along the stretch of t2s. while one of them was characterised by gravels forming a steep, lower beachface, and gentle, upper beachface, which are typical for t1s (figs. 7, 8), the other, which was probably more common, was represented by foreshore gravels. the foreshore type of gravelly coasts in t2s might indicate lower storm-wave energy and/or a smaller fetch compared to the coasts with a steep beachface. the characean-bearing limestone discovered above a conglomerate body probably represents a short-term coastal pond developed above the beachface gravel in the backbeach area, at the end of beach progradation. the type 2 succession is overlain by open-shelf mudstones intercalated with tempestites which represent the basal part of the basin-wide highstand unit, generally consisting of shelf to delta and shelf to beach cycles as in t1s (babić & zupanič, 2007, babić et al., 2010; zupanič & babić, 2011). 4.3. type 3 succession (t3s) – mratovo to razvođe (figs. 6, 24) 4.3.1. description this type of succession is represented by a synthetic log (fig. 24) reconstructed mainly using rare, isolated, smaller outcrops found along the 5km long stretch (labelled “3” in fig. 6). in fact, the lower to middle part of t3s is exposed in escarpments of abandoned bauxite pits. however, only the lowermost part of the succession, i.e. the basal contact and part of the lowermost limestone unit, were locally accessible for close observation while the rest was poorly exposed at the margins of the pits (e.g. fig. 25a). the type 3 succession is underlain by the basin basement, i.e. middle eocene foraminiferal limestones (locally, upper cretaceous limestones) and sporadic bauxite deposits (fig. 24). the succession starts with limestones, either above an irregular, karstifi ed surface, locally showing kamenicatype depressions (=solution pans; e.g. jennings, 1985) and dense borings by lithophagid bivalves (fig. 25b), or above the bauxite. in the later case, the uppermost bauxite layer may contain corals and bivalves (pavlovec, 1959; sakač, 1966), or there may be a few decimetres thick coaly shale lens above the bauxite. the basal limestone unit is a prominent, fossil-rich unit, previously identifi ed by sakač (1970) in the se part of its extent. it contains 10 to 20% non-carbonate component (pavlovec, 1959), in contrast to the “cleaner” limestones of all the other limestone units. the abundance of fossils is shown by the common occurrence of skeletal rudstones (fig. 25b), in addition to wackestones, packstones and mudstones. pavlovec (1959) identifi ed nummulites, miliolids, corals (35 species), bivalves (35 species including oysters), gastropods (32 species), echinoids, hydrozoans, scaphopods and cephalopods. discocyclina, opeculina, sphaerogypsina, orbitolites, chapmanina, acervulinids and other foraminifera have also been discovered, as well as bryozoans and corallinaceans. in some bauxite pits, lime mudstones dominate the lower part of the succession and may contain common figure 24: log of t3s (mratovo-razvođe). reconstructed using smaller, partial sections and isolated outcrops located along 5km long, discontinuous stretch of t3s (labelled “3” in fig. 16). the basement is mostly represented by middle eocene foraminiferal limestones (fl) and locally, by upper cretaceous limestones. for other symbols see fig. 16. geologia croatica 65/1geologia croatica 18 carbonised plant remains. a bauxite pit shows two 40cm thick, erosionally based, normally graded, and inverse to normally graded layers of mixed gravel and skeletal debris, which alternate with mudstones and occur above basal limestones. they might belong to the middle part of the succession which is poorly known and might be laterally variable. an isolated outcrop of the middle part of the succession includes a limestone unit transgressively overlying probable shoreline conglomerates. the uppermost limestone unit appears to be laterally persistent. as in t1s and t2s, it overlies conglomerates, starts with a foraminifera-bearing conglomeratic basal layer, and includes packstones, wackestones and mudstones with miliolids, larger foraminifera (e.g. discocyclina), bivalves and gastropods. close to its top, it contains abundant skeletal fragments and possible glauconite. the type 3 succession is overlain either by mudstones or alternating mudstones and calcarenites comparable to those characterising t1s and t2s. 4.3.2. interpretation the transgression covered the karstifi ed basement, as well as bauxite deposits as indicated by features observed along the contact. the creation of local marshes above the bauxite, (precursors of coaly deposits), was caused by rising groundwater which may have been related to marine fl ooding in areas located further seawards (sections 4.4. and 4.5.). the lowermost limestone unit refl ects the installation of very shallow carbonate settings characterised by abundant and diverse biota (pavlovec, 1959), in the close vicinity of land areas which is indicated by the increased clay content compared to other limestone units. this might result from locally restricted circulation in more isolated bays as suggested by frequent carbonised plant remains. normally graded, and inverse to normally graded, fossiliferous conglomerates from the middle part of t3s, are event beds which could have originated by mixing of eroded shoreline gravel and shallow-marine skeletal material, and dumping into the quiet neighbouring environment. this could have been related to a strong storm or a tsunami. the middle part of the succession is poorly understood and is only tentatively reconstructed in fig. 24. the uppermost limestone unit evolved mainly in the same manner as those in t1s and t2s described above. this includes a carbonate platform setting and a decrease in sedimentation rates towards the top. the overlying shelf deposits are also similar to those from previously described successions. 4.4. type 4 succession (t4s) – krstančuša (figs. 6, 26) bauxite deposits overlying middle eocene foraminiferal limestones are in turn, overlain by a 0.1 to 2.3m thick lignite coal (nikler, 1982). excavated rock debris around abandoned coal pits comprises fragments of coal, coaly shale, as well as laminated limestones with bivalves, which might represent lacustrine stromatolites overlying the coaly unit. closely associated marine mudstones appear to overly the sediments of the pits. coaly sediments were deposited in marshes, which originated due to the rise of the water table related to a relative sea-level rise. lacustrine limestones and marine mudstones which presumably represent subsequent sedimentation, might refl ect a continuation of the groundwater and relative sea-level rise. hence, the tentatively reconstructed succesfigure 25: t3s of the mratovo-razvođe area, figs. 6 and 24. a – succession in radasi bauxite pit, location in fig. 6. karstifi ed middle eocene foraminiferal limestones (fl) of the basin basement is left, below bauxite (bx). the bauxite has been sheared and squeezed, and thins toward the topographic surface. it is overlain by a 3–5m thick fossiliferous limestone unit (l1, reduced in the upper left due to a thrust fault). the remaining succession is poorly known. it includes marine calcarenites and conglomerates, followed by a limestone unit (l2) and a younger unit of marine calcarenites and conglomerates. b – transgressive surface separating light cretaceous limestone, and brownish limestone, the basal part of the transgressive unit. left, a kamenica type depression (solution pan). right, lithophagid borings fi lled by transgressive, marine sediment. transgressive limestone is a skeletal rudstone. lens cap = 4.4cm. bauxite pit e of dujići village. c – thin-section of limestone showing orbitolites, miliolids and other foraminifera. basal limestone unit in the radasi bauxite pit. b and c. location in fig. 6. babić and zupanič: laterally variable development of a basin-wide transgressive unit of the north dalmatian foreland basin... geologia croatica 19 sion and the character of correlatable successions suggest that the freshwater sediments represent a terrestrial variant of the marine transgressive unit (shanley & mccabe, 1994), following the sequence-stratigraphic approach (fig. 26-left; see also section 4.5. and discussion in section 5.), while the overlying mudstones belong to a regressive sedimentation. 4.5. type 5 succession (t5s) – počivalica (figs. 6, 26) 4.5.1. description the type 5 succession is underlain by an alluvial unit consisting of two main facies associations similar to those below the t2s. the fi rst one consists of laterally extensive sheetlike bodies of massive, horizontally bedded to gently inclined, and locally cross-bedded conglomerates, which include intercalations and lenses of laminated calcarenites, and represent deposits of braided streams (babić & zupanič, 2007; babić et al., 2010; zupanič & babić, 2011). the second facies association includes plane laminated, crossbedded and current-ripple laminated calcarenites and mudstones which commonly show pedogenic alteration, and refl ect deposition on fl oodplains (op. cit.). the basal contact surface t5s is locally irregular and separates underlying alluvial conglomerates from a clay < 30cm thick, containing coal laminae, which is followed by limestones (figs. 26, 27). eastwards, outside the study area, this basal clay is overlain by a lignite horizon (up to several metres thick), which represents the main coal bed formerly mined in mt. promina (marković, 2002). it is overlain by alternating clastics, limestones and coaly sediments, all of which are considered to represent the transgressive systems tract (zupanič & babić, 2011). during early coal mining, remains of a hog and a crocodile were found in these sediments (kerner, 1901). w of section 5 (fig. 6), laminated limestones may directly overlie alluvial conglomerates. the limestones of t5s are commonly laminated and contain ostracods, gastropods and bivalves. cyanobacterial fi laments, characean gyrogonites (fig. 27b) and incrustations of characean stems, as well as plant leaves have also been observed. other limestones are mudstones, wackestones and rare packstones with ostracods and/or molluscs. the t5s limestones may be intensely bioturbated. limestones are overlain by mudstones which display rare, smaller benthic and planktonic foraminifera and bivalves. plant remains, including leaves, are common. a few metres upwards, the mudstones become intercalated with laminae and thin beds of calcisiltites and calcarenites. they are sharply based and may be parallel or cross-laminated. the fi rst intercalations in mudstones may laterally be represented by sharply based, bioturbated lime packstones dominated by benthic foraminifera. 4.5.2. interpretation the clay and lignite represent marsh deposits of forested areas (cf. tucker, 2001). such environments were the habitats of hogs and crocodiles reported by kerner (1901). the features observed in the limestones refl ect deposition in a lake, the bottom of which was largely covered by cyanobacterial mats, and partly vegetated by characeans and aquatic macrophytes. ostracods, bivalves and grazing gastropods also inhabited the lakes. the overall conditions correspond to a shallow, hard-water lake (review in tucker figure 26: logs of t4s (krstančuša) and t5s (počivalica). note that limestones in the transgressive unit are lacustrine in character. t5s is mainly after zupanič & babić (2011). for details see text. fl, middle eocene foraminiferal limestones of the basin basement. for other symbols see fig. 16. location in fig. 6. figure 27: t5s, lower part of section 5 (fig. 26). location in fig. 6. a – the clay and coal in the lower part (dark) are overlain by thin bedded, laminated lacustrine limestones. hammer = 32cm. b – thin-section of the lacustrine limestone showing characean gyrogonites. geologia croatica 65/1geologia croatica 20 & wright, 1990). the onset of t5s was related to a rise in groundwater level which in turn was induced by a relative sea-level rise further basinwards (babić & zupanič, 2007; zupanič & babić, 2011). the type 5 succession is overlain by mudstones, the features of which indicate a change in environmental conditions, from a carbonate lake to open marine setting. the mudstones and subsequent alternation of mudstones, calcisiltites and calcarenites, as well as foraminiferal tempestites, represent shelf deposits, i.e. the basal part of cyclic shelf to delta, and shelf to beach deposition of the highstand (babić & zupanič, 2007; babić et al., 2010). 4.6. type 6 succession (t6s) – bibići (figs. 6, 28) t6s is underlain by alluvial sediments similar to those previously described from correlative sections located to the east (zupanič & babić, 2011). this alluvium ends with a thick conglomerate bed. the upper surface of this conglomerate exhibits bivalve borings fi lled with lime packstone (fig. 29) containing miliolids, other smaller benthic foraminifera, echinoids, molluscs and rare limestone clasts. the conglomerate surface is overlain by 25cm (up to 50cm?) of lime packstones containing miliolids and other smaller benthic foraminifera, bivalves, gastropods, echinoids, bryozoans, as well as rare corallinaceans and planktonic foraminifera. after a gap in exposure, the succession continues with massive to crudely bedded mudstones with occasional gastropods and bivalves. the transgression therefore started with the organic boring of a lithifi ed alluvial substrate and an infi lling of the voids, and continued by the installation of a shallow-marine carbonate environment which quickly deepened, as suggested by the occurrence of planktonic foraminifera close to the basal contact. the mudstones which follow indicate an offshore shelf setting at the beginning of the regression. 4.7. type 7 succession (t7s) – šarenica (figs. 6, 28) the type 7 succession is represented by a single, fossiliferous limestone unit which overlies middle eocene foraminiferal limestones of the basin basement and has already been identifi ed and mapped by sakač (1970). at the contact between the two units there are calcrete, microcodium and limestone breccias, while the basal part of the fossiliferous limestones contains scattered bauxite particles. the limestones are nodular, bioturbated wackestones, packstones and mudstones (fig. 30) containing smaller benthic foraminifera, nummulites, discocyclina (common), operculina, corals, echinoids, bivalves, gastropods, bryozoans and corallinaceans. the upper part of the unit includes planktonic foraminifera and glauconite (zupanič & babić, 2011), as well as common skeletal debris. the limestones are overlain figure 28: logs of t6s (bibići) and t7s (šarenica). fl, middle eocene foraminiferal limestones of the basin basement. for other symbols see fig. 16. for details see text. location in fig. 6. figure 29: t6s (bibići). transgressive surface (seen in plan view) is represented by the upper surface of an alluvial conglomerate which displays lithophagid borings fi lled by lime packstones containing foraminifera, echinoids, molluscs and rare lithoclasts. the surface is laterally (out of the photo) overlain by marine limestones. see also log in fig. 28. location in fig. 6. figure 30: t7s. irregularly bedded (rippled?), bioturbated, marine limestones. close to section 7 (šarenica) in fig. 6. hammer = 32cm. babić and zupanič: laterally variable development of a basin-wide transgressive unit of the north dalmatian foreland basin... geologia croatica 21 by mudstones with occasional bivalves and planktonic foraminifera which are intercalated by thin, skeletal packstones rich in benthic foraminifera. the limestones therefore start transgressively and unconformably above karstifi ed carbonates of the basin basement. they refl ect deposition on a carbonate platform which ended with condensed sedimentation in a relatively deeper platform setting. the deposition of t7s was followed by shelf muds with foraminiferal tempestites indicating a major change in depositional trend, representing the onset of the regressive trend (zupanič & babić, 2011). 5. discussion 5.1. onset of transgression: variability of the major transgressive surface the character of the studied unit, observed and compared across the basin, suggests that the sediments bounded by two major discontinuity surfaces are products of one and the same transgressive event. instead, the onset of transgression was related to different situations encountered along the extent of the basal bounding surface that is summarised in fig. 31 . the fi rst case is represented by marine fl ooding over the alluvium, which includes transgressive erosion (ravinement), (t2s and t6s, fig. 31). the resultant bounding surface is more specifi cally a transgressive surface of erosion, following sequence-stratigraphic terminology (review in catuneanu, 2006). lacustrine fl ooding over the alluvium (t5s) forms part of the second case. this surface type may be generally termed the transgressive surface having in mind a basin-wide stratigraphic context (fig. 31). however, it is also a maximum regressive surface (term after helland-hansen & martinsen, 1996), if the term is restricted here to imply the non-erosive character of the surface, i.e. the preservation of the underlying, uppermost regressive (alluvial) deposits. the third variation of the major bounding surface which has been encountered along its extent, is marked by fl ooding (marine and lacustrine) of middle eocene and cretaceous basement rocks (t3s, t4s, t7s; fig. 31). this relationship is related to a large stratigraphic hiatus which separates genetically unrelated strata, thus representing an important subaerial unconformity. such features are usually taken to characterise sequence boundaries, and our examples may also be designated as a sequence boundary/transgressive surface (posamentier & allen, 1993). this type of bounding surface resulted from a transgressive onlap over subaerially exposed parts of the basin basement (figs. 31, 32). this contrasts with other boundary types located along the same bounding surface at short distances, and indicates tectonic uplift areas generated by previous intrabasinal folding and faulting. such processes have previously been described from mt. promina and other parts of the basin where several periods of deformation occurred (zupanič & babić, 2011). the differences along the basal discontinuity surface make it comparable to a 2nd or 3rd order sequence boundary of embry (1995), which has been described as being represented by a conformable boundary in the undeformed part of the basin, and a subaerial unconformity at the deformed figure 31: comparison of all seven succession types (t1s to t7s) of the studied transgressive unit. datum is the major transgressive-regressive turn around surface. the correlation is allostratigraphic in character. logs are simplifi ed from those in figs. 7, 16, 24, 26 and 28. log 2 is a compilation of ten logs (2a to 2j in fig. 16). log 4 is a tentative reconstruction of t4s. for discussion see text. geologia croatica 65/1geologia croatica 22 basin margin. at the same time, our transgressive unit may represent the transgressive segment of embry’s (1995, 2002) transgressive-regressive sequence of 2nd or 3rd order. this sequence-stratigraphic classifi cation and terminology, as well as related views, may be used for promina units as alternatives to that discussed above and should be considered in further studies in this foreland basin. 5.2. end of transgression: maximum fl ooding and major transgressive-regressive turnaround the condensed horizon indicating a lowering of sedimentation rates and more open, deeper marine settings toward the end of transgression, refl ects a relative sea-level rise which outpaced carbonate production. namely, carbonate production generally decreases with increasing depth, other parameters being about equal (tucker & wright, 1990). the condensed horizon corresponds to the “condensed section” of the sequence stratigraphic approach, which originated when the shoreline was at its farthest landward position (e.g. loutit et al., 1988; posamentier & allen, 1999). the studied examples show that the condensation processes started close to the major turnaround from transgressive to regressive trends, and coincident maximum fl ooding. shelf to delta and shelf to beach cycles which follow this surface have been proposed as corresponding to the highstand systems tract (babić & zupanič, 2007; zupanič & babić, 2011). the relevant turnaround surface is inferred to continue laterally into the surface separating lacustrine limestones and the overlying, cyclic, marine deposits of the same regressive succession mentioned above (fig. 31). the upward transition from lacustrine to marine settings, might have been brought about by the ingress of marine waters into depressions hitherto occupied by lakes. in this case, maximum fl ooding could have been located slightly above the major transgressive-regressive turnaround surface, within overlying regressive mudstones. the possibility that dark mudstones revealed at the base of regressive deposits in e mt. promina, (out of the study area) refl ect a restricted circulation at the very beginning of the regression, as speculated previously (zupanič & babić, 2011), awaits further investigation. 5.3. importance of the studied transgressive unit and its bounding surfaces for basin stratigraphy as described and discussed in previous sections and summarised in section 5.1., and figs. 31 and 32, the lower bounding surface of the studied unit, acquired different characteristics along its extent, including the characteristics and ages of the underlying units. this variability, as well as common gaps in exposure, may complicate its identifi cation at some locations and tracking, especially in the tectonically more complex areas se of the krka river. in contrast, the upper bounding surface of the transgressive unit, i.e. the major surface of the transgressive-regressive turnaround, can be more easily identifi ed by its own features and its position within vertical successions. this is consistent with general experience that this type of key sequence-stratigraphic surface is easier to identify than other types (galloway, 1989; review in catuneanu, 2006). this is also the reason why this type of stratigraphic surface was proposed by galloway (1989) to be marked as a sequence boundary, i.e. the main bounding surface used for subdivision and correlation of sedimentary successions. the studied transgressive unit and its bounding surfaces are the only stratigraphic elements described until now which extend across the entire north dalmatian foreland basin (figs. 5, 6). hence, their features may be useful in further studies of basin stratigraphy and evolution. figure 32: tentative, highly simplifi ed section including all succession types (1–7) of the studied transgressive unit. datum is the major transgressiveregressive turnaround surface. types 1 and 2 are strike parallel over the major part of the basin (figs. 5, 6). types 3 to 7 are situated in more complex tectonic structures and their original distribution is only partly known. note lateral diff erence in the character of the rocks which were transgressed (below ts), which contrasts laterally uniform character of the overlying deposits (above t/r surface). the correlation shown for the middle part of the unit in succession types 2 and 3 is poorly documented. the character of two inferred faults is not implied. ts, t/r and fs are transgressive surface, transgressive/regressive turnaround and fl ooding surface, respectively. for discussion see text. not to scale. babić and zupanič: laterally variable development of a basin-wide transgressive unit of the north dalmatian foreland basin... geologia croatica 23 out of the study area and much lower within the basin succession (lower promina beds), there are surfaces envisaged to represent sequence boundaries (babić & zupanič, 2007; mrinjek, 2008; babić et al., 2010) which might be important for an extensive stratigraphic correlation in the lower part of the basin fi ll. however, their number and lateral extent remain to be studied and their importance evaluated. 5.4. basic building units: high-frequency transgressive-regressive cycles within the major part of the basin, (from novigrad to razvođe; t1s, t2s, t3s; figs. 6, 7, 16, 24) the studied transgressive unit consists of lower-rank (high-frequency) stratigraphic units, which ideally includes a transgressive, limestone segment, and a regressive, cu segment (section 4.1., fig. 8). these units are called cycles here which is a more general term compared to parasequence. in fact, similarities of the cycles described here with the units commonly treated as parasequences do exist, as both of them are stacked, build the units of systems tracts, and are bounded by fl ooding surfaces. however, the use of the term parasequence is recommended for fl ooding-surface-bound, shoaling-upward successions, principally originating in shallow, near-shore environments, which commonly start with a transgressive lag and are separated by a thin limestone, phosphate or glauconitic deposit (posamentier & allen, 1999; catuneanu, 2006). in contrast, the cycles described here may include relatively thick transgressive segments (limestones), the thickness of which may even surpass the thickness of the overlying regressive (= shoaling-upward) segment. consequently, the term parasequence is not regarded as appropriate for the current examples. alternatively, the cycles described here are comparable to the 3rd or higher order transgressive-regressive (t-r) sequences of embry (1995, 2002) which are only traceable along part of the basin. as previously mentioned above, this classifi cation and related views on the stratigraphy should be considered in future work in the n dalmatian foreland basin. 5.5. the studied transgressive unit as formal stratigraphic unit: defi nition of the novigrad alloformation correlation of the studied sedimentary successions is summarised in fig. 31, which shows the characteristics of the studied transgressive unit as a whole. it is proposed that the unit be defi ned as a formal allostratigraphic unit of alloformation rank, in accordance with the requirements of nacsn (1983). the unit is shown to be mappable, and is described by its bounding discontinuities, extent, relative stratigraphic position, lithologic features, as well as its lateral and vertical variability. along its extent, it may be represented by alternating transgressive limestones and a regressive clastics (t1s, t2s, t3s; figs. 7 to 25), lacustrine deposits, mainly limestones (t4s, t5s; fig. 26), and by a single marine limestone unit (t6s, t7s; figs. 27 to 30). genetic interpretations are not required, however they can help in choosing boundaries and matching sediments along the extent of the unit (nacsn, 1983), as was the case here. the thickest and best exposed section at novigrad (t1s, figs. 7 to 15) is proposed for the type section and the name of this town as the geographic part of the unit name, hence the novigrad alloformation. its variability required defi nition of reference sections in order to demonstrate the totality of the stratigraphic unit (nacsn, 1983), as well as to compensate for the incompleteness of available sections. for this purpose, sections 2d, 3 (radasi), 5 and 7 (figs. 16, 24, 25a, 26, 28) are chosen, as they document the character and variability of the basal bounding discontinuity. two of these sections (5, 7) also display the lithological variability of the unit as it is represented by lacustrine deposits and a single limestone unit, respectively, in contrast to other, lithologically heterogeneous sections including the type section. section 2g (figs. 16, 17) is also selected as a reference section as it includes the best exposure of the upper bounding surface of the unit. two stratigraphic units previously described from mt. promina represent parts of the newly proposed novigrad alloformation: “middle lacustrine unit” and “fossiliferous limestones” (zupanič & babić, 2011). the fi rst one is represented by section 5 (fig. 26), and the second one is identical to the limestones of section 7 (fig. 28). each of the previously described units has been given two formal names of both the lithostratigraphic and allostratigraphic categories (e.g. počivalica formation and počivalica alloformation), however, it was not mentioned which of the two is chosen. hence, these formal names cannot be valid. 5.6. possible driving mechanisms for generating the stratigraphy of the studied sediments the basin-wide extent of both the transgression at the base of the studied transgressive unit and transgressive-regressive turnaround at the end of the unit, suggest allogenic control on related processes. the transgression might have been mainly caused by backtilting of an inner part of the foreland basin (in front of dinaric nappes) related to a tectonic pulse (zupanič & babić, 2011). this would have caused an increase in subsidence rates in the study area and a landward shift of detrital sedimentation related to thrust-load emplacement, as proposed in models by heller et al. (1988) and burns et al. (1997). according to the model by heller et al. (1988), the transgressive-regressive turnaround could have been induced during the “postorogenic phase of adjustment”, when clastics eroded from the orogen deformed by the previous tectonic pulse, reached relevant part of the basin. alternatively, the transgression might have resulted from a eustatic rise, which accelerated relative sea-level rise in the proximal part of the foreland basin characterised by increased subsidence rates compared to its distal part, (posamentier & allen, 1993) or by eustatic sea level rise alone. the onset of clastic deposition, i.e. the transgressivegeologia croatica 65/1geologia croatica 24 regressive turnaround, might have been predominantly infl uenced by a decrease in eustatic sea-level rise which enables clastics to prograde. precise dating of sedimentary successions, (currently unavailable) might be relevant in answering these questions. the origin of basic, transgressive-regressive cycles is poorly understood due to diffi culties in correlation along their lateral extent. lateral differences, locally identifi ed over rather short distances, suggest that important parts of successions have been generated under the infl uence of local conditions, such as the lateral variation in sediment supply and lateral shifting in local depocentres, as well as localised tectonic processes. these processes may have been combined with an overall, relative sea-level rise due to allogenic processes. as to t1s, which is considerably thicker compared to neighbouring t2s and t3s, the difference could have resulted from a higher rate of synsedimentary subsidence of this part of the basin. this could have been related to the position of this area in the nw part of the basin, where there was a better connection with the open sea (section 2; fig. 2). 5.7. aspects of time correlation it is known that not only the transgressive surface but also the maximum fl ooding surface may be diachronous, both perpendicular and parallel to the shoreline (reviews in posamentier & allen, 1999; catuneanu, 2006). a small scale illustration of the process is provided by the input of lithoclasts to the carbonate depositional area identifi ed about 1m above the base of the limestone, i.e. above the basal transgressive surface (section 4.2.). this feature shows a coeval advance of fl ooding over the underlying alluvium, and related diachroneity along the relevant stratigraphic surface. the onset of t6s and t7s, consisting of a single marine limestone unit (fig. 28), might represent later fl ooding of the area in the close vicinity of the larger tectonic structures, i.e. a later marine onlap onto the basement rocks of the inner basin margin, where the same surface becomes not only a transgressive surface but also assumes the character of a surface which would commonly be designated as the sequence boundary. it is possible that the marine transgression related to the deposition of these limestones is coeval or partly coeval with the condensation basinwards. the origin of the lakes, presumably related to rising groundwater levels, was in turn related to a relative sea-level rise elsewhere, (the situation reviewed by shanley & mccabe, 1994), and lacustrine deposition may be regarded as being coeval with the lower part of the marine deposition basinwards (out of the study area). this does not exclude the possible connection of the lakes to fl uvial systems which were located landwards (out of the study area). the end of the transgression, identical to the transgressive-regressive turnaround, may or may not be quasi synchronous throughout the study area. instead, it might have been slightly older landwards (primarily t6s and t7s) in comparison to the situation basinwards. 5.8. stratigraphic and genetic interpretations and related fi eld relationships in the nw part of the basin (between pridraga and rodaljice, fig. 6a), the studied unit extends across two stratigraphic units of mrinjek & pencinger (2008). (1) sw of the karin sea, their map and log (their figs. 4 and 5) include an approximately 75m thick unit of off-shore mudstones with thin calcarenites, proposed to represent a transgressive-regressive unit (their karišnica unit). our observations in this area indicate that the lower part of their unit includes a rather thick alluvial unit, dominantly conglomerates, which are followed by the transgressive unit described here, while the upper part of their unit is represented by cycles consisting of shelf to conglomeratic shoreline deposits (babić & zupanič, 2007; babić et al., 2010; this work; fig. 6a). (2) the second unit of mrinjek & pencinger (2008) is > 450m of regressive deposits interpreted to consist of lower shoreface to mouth-bar sequences (their žedna greda unit). based on our data, a considerable part of the relevant area is occupied by alluvial deposits. they are overlain by the transgressive unit described here which stretches obliquely across the middle part of the supposed regressive unit (between karin donji and rodaljice, fig. 6a). in the central part of the basin, (between nunić and mudrinići, fig. 6b), mrinjek (2008, his figs. 6 and 7), envisaged a belt consisting of an approximately 140m thick, transgressive to regressive unit of shelf deposits (his kistanje unit), believed to be underlain and overlain by both deltaic and fl uvial facies. based on our observations, the succession in this area consists of an alluvial unit at the base, a transgressive unit, and shelf to shoreline cycles (babić & zupanič, 2007; babić et al., 2010; this work; fig. 6b). 6. summary and conclusion the sedimentary fi ll of the palaeogene north dalmatian foreland basin includes a prominent transgressive unit, which stretches for more than 63 km along the basin and represents the middle promina beds. it is bounded by major, objectively delineated discontinuity surfaces: the lower, transgressive surface, and upper, transgressive-regressive turnaround surface. hence, the studied unit is allostratigraphic in character and is formally named the novigrad alloformation. it overlies both the braided alluvium of the lower promina beds and karstifi ed middle eocene and cretaceous carbonates of the basin basement. the unit exhibits a lateral variability and may be represented either by stacked, high-frequency, transgressive-regressive cycles, by lacustrine deposits, or a single marine limestone unit. an ideal transgressive-regressive cycle includes a transgressive segment of shallow-marine limestones, and a regressive segment of storm-wave dominated, shelf to gravelly beachface (cu) deposits. gravelly beaches have been represented by several types. one of them included the steeply inclined, lower beachface which is situated below the intertidal zone. the cycles are separated by lower-rank discontinuity surfaces (fl ooding surfaces), while two segments are separated babić and zupanič: laterally variable development of a basin-wide transgressive unit of the north dalmatian foreland basin... geologia croatica 25 by a lower-rank transgressive-regressive turnaround surface. lacustrine deposits originated due to a rise in groundwater which was induced by a sea-level rise occurring basinwards. the single limestone unit exhibits a transgressive onlap over tectonically uplifted, exposed basin basement. maximum transgression is indicated by a condensed horizon overlain by a major transgressive-regressive turnaround surface. the evolution following the transgressive unit is almost uniform along its extent, and includes shelf to delta and shelf to shoreline cycles of the upper promina beds (highstand). the identifi cation of the studied allostratigraphic unit may be useful in further studies of the basin stratigraphy and evolution. acknowledgement this work formed part of the project “evolutionary changes of the dinarides from subduction to modern adriatic beaches“ supported by the ministry of science, education, and sport of the republic of croatia. we thank a.g. plint and an anonymous reviewer for constructive criticism which improved the manuscript. in addition, detailed comments by a.g. plint were very helpful in clarifying several aspects of the content. we also thank m. kovačić for his help in photomicrograph production, and r. košćal for the artwork. b. lužar-oberiter and j. robson are thanked for correcting the english text. appendix the palaeogene versus neogene age controversy the work on facies analysis related to this study must have included identifi cation of the main fossil groups. among them, larger foraminifera reported from the majority of limestone units, have been identifi ed at a generic level. they may be used to briefl y comment on considerable differences in the hitherto proposed age interpretations of n dalmatian foreland basin sediments. namely, in contrast to the eocene age for the largest part of the north dalmatian foreland basin sediments, and possible oligocene age for their uppermost part, suggested by several authors (schubert, 1905; mamužić, 1975, ivanović et al., 1976, 1978, with references), mikes et al. (2008) proposed a miocene age for the lower part of the basin fi ll (traditionally called fl ysch, fig. 5) based on nannoplankton. the unit described here occurs within the middle part of the overall basin succession, and foraminiferal associations found in shallow-marine limestones of this unit (section 4) indicate an eocene age, apart from the presented generic level of taxonomic determinations (boudagher-fadel, 2008). it follows that the entire succession of this basin situated below the studied unit, and including sediments analysed by mikes et al. (2008), is eocene in age, as suggested by previous authors. consequently, reconstructions of the tectonic evolution of north dalmatia cannot be based on a miocene age of these sediments as suggested by mikes et al. (2008). references allen, p.a. & allen, j.r. (2005): basin analysis.– 2. ed. blackwell, malden, 549 p. babić, lj. & zupanič, j. (2007): major events and stages in the sedimentary evolution of the paleogene promina basin (dinarides, croatia).– natura croat., 16/4, 215–232. babić, lj. & zupanič, j. (2008): evolution of a river-fed foreland basin fi ll: the north dalmatian fl ysch revisited (eocene, outer dinarides).– natura croat., 17/4, 357–374. babić, lj., zupanič, j. & kurtanjek, d. (1995): sharply-topped alluvial gravel sheets in the palaeogene promina basin (dinarides, croatia).– geol. croat., 48/1, 33–48. babić, lj., zupanič, j. & lužar-oberiter, b. (2010): evolution of a dinaric foreland basin fi ll: fl ysch and molasse of north dalmatia.– in: horvat, m. (ed.): 4th croatian geological congress, šibenik 2010, excursion guide-book, zagreb, 179–201. beaumont, c. (1981): foreland basins.– geophys. j. r. astr. soc., 65, 291–329. boudagher-fadel, m.k. (2008): evolution and geological signifi cance of larger benthic foraminifera.– development in palaeontology and stratigraphy, 21, elsevier, 540 p. bourgeois, j. & leithold, e.l. (1984): wave-worked conglomerates – depositional processes and criteria for recognition.– in: koster, e.h. & steel, r.j. (eds.): sedimentology of gravels and conglomerates. can. soc. petroleum geol., mem., 10, calgary, 331–343. burns, b.a., heller, p.l., marzo, m. & paola, c. (1997): fluvial response in a sequence stratigraphic framework: example from the montserrat fan delta, spain.– j. sediment. res., 67/2, 311–321. catuneanu, o. (2006): principles of sequence stratigraphy.– elsevier, amsterdam, 375 p. clifton, h.e. (1981): progradational sequences in miocene shoreline deposits, southeastern caliente range, california.– j. sediment. petrol., 51/1, 165–184. dupré, w. (1984): reconstruction of paleo-wave conditions during the late pleistocene from marine terrace deposits, monterey bay, california.– marine geol., 60, 435–454. embry, a.f. (1995): sequence boundaries and sequence hierarchies: problems and proposals.– in: steel, r.j., felt, v.l., johannessen, e.p. & mathieu, c. (eds.): sequence stratigraphy on the northwest european margin. norwegian petroleum society (npf), spec. publ., 5, elsevier, 1–11. embry, a.f. (2002): transgressive-regressive (t-r) sequence stratigraphy.– in: armentrout, j.m. & rosen, n.c. (eds.): sequence stratigraphic models for exploration and production: evolving methodology, emerging models and application histories. 22. ann. gulf coast sect. sepm foundation bob f. perkins res. conf., conf. proc., 151–172. flügel, e. (2004): microfacies of carbonate rocks.– springer, berlin, 976 p. galloway, w.e. (1989): genetic stratigraphic sequences in basin analysis i: architecture and genesis of fl ooding-surface bounded de positional units.– am. assoc. petroleum geol. bull., 73/2, 125–142. hart, b.s. & plint, a.g. (1989): gravelly shoreface deposits: a comparison of modern and ancient facies sequences.– sedimentology, 36/4, 551–557. hart, b.s. & plint, a.g. (1995): gravelly shoreface and beachface deposits.– in: plint, a.g. (ed.): sedimentary facies analysis. spec. publs. int. ass. sediment., 22, 75–99. geologia croatica 65/1geologia croatica 26 helland-hansen, w. & martinsen, o.j. (1996): shoreline trajectories and sequences: description of variable depositional-dip scenarios.– j. sediment. res., 66/4, 670–688. heller, p.l., angevine, c.l. & winslow, n.s. (1988): twophase stratigraphic model of foreland basin sequences.– geology, 16/6, 501–504. ivanović, a., sakač, k., marković, s., sokač, b., šušnjar, m., nikler, l. & šušnjara, a. (1973): osnovna geološka karta sfrj 1:100000, list obrovac [basic geological map of sfry 1:100000, obrovac sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. ivanović, a., sakač, k., sokač, b., vrsalović-carević, i. & zupanič, j. (1976): osnovna geološka karta sfrj 1:100000. tumač za list obrovac [basic geological map of sfrj 1:100000, geology of the obrovac sheet – in croatian, english abstr.].– geološki zavod, zagreb, savezni geološki zavod, beograd, 61 p. ivanović, a., sikirica, v., marković, s. & sakač, k. (1977): osnovna geološka karta sfrj 1:100000, list drniš [basic geological map of sfry 1:100000, drniš sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. ivanović, a., sikirica, v. & sakač, k. (1978): osnovna geološka karta sfrj 1:100000. tumač za list drniš [basic geological map of sfry 1:100000, geology of the drniš sheet – in croatian, english abstr.].– geološki zavod, zagreb, savezni geološki zavod, beograd, 59 p. jennings, j.n. (1985): karst geomorphology.– basil blackwell, 293 p. kerner, f. v. (1901): erläuterungen zur geologischen karte der oesterr.-ungar. monarchie. kistanje-dernis, 1:75.000.– geol. reichsanst., wien, 40 p. korbar, t. (2009): orogenic evolution of the external dinarides in the ne adriatic region: a model constrained by tectonostratigraphy of upper cretaceous to paleogene carbonates.– earth-sci. reviews, 96/4, 296–312. leithold, e.l. & bourgeois, j. (1984): characteristics of coarsegrained sequences deposited in nearshore, wave-dominated environments – examples from the miocene of south-west oregon.– sedimentology, 31, 749–775. loutit, t.s., hardenbol, j., vail, p.r. & baum, g.r. (1988): condensed sections: the key to age dating and correlation of continental margin sequences.– in: c.k. wilgus, b.s. hastings, c. g. st. c. kendall, h.w. posamentier, c.a. ross & j.c. van wagoner (eds.): sea-level changes: an integrated approach. sepm, spec. publ., 42, 183–213. majcen, ž. & korolija, b. (1973): osnovna geološka karta sfrj 1:100000. tumač za list zadar [basic geological map of sfry 1:100000, geology of the zadar sheet – in croatian, english abstr.].– geološki zavod, zagreb, savezni geološki zavod, beograd, 44 p. mamužić, p. (1971): osnovna geološka karta sfrj 1:100000, list šibenik [basic geological map of sfry 1:100000, šibenik sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. mamužić, p. (1975): osnovna geološka karta sfrj 1:100000. tumač za list šibenik [basic geological map of sfry 1:100000, geology of the šibenik sheet – in croatian, english abstract].– geološki zavod, zagreb, savezni geološki zavod, beograd, 37 p. marković, s. (2002): hrvatske mineralne sirovine.– institut za geološka istraživanja, zagreb, 544 p. marinčić, s. (1981): eocenski fl iš jadranskog pojasa [eocene fl ysch of adriatic area – in croatian, english abstr.].– geol. vjesnik, 34, 27–38. massari, f. & parea, g.c. (1988): progradational gravel beach sequences in a moderateto high-energy, microtidal marine environment.– sedimentology, 35, 881–913. miall, a.d. (2000): principles of sedimentary basin analysis.– 3. ed., springer, berlin, 616 p. mikes, t., báldi-beke, m., kázmér, m., dunkl, i. & von eynatten, h. (2008): calcareous nannofossil age constraints on miocene fl ysch sedimentation in the outer dinarides (slovenia, croatia, bosnia-herzegovina and montenegro).– in: siegesmund, s., fügenschuh, b. & froitzheim, n. (eds.): tectonic aspects of the alpine-dinaride-carpathian system. geol. soc. spec. publ., 298, london, 335–363. mrinjek, e. (2008): excursion 3a, split–rab, promina beds in canyon of krka river and bribirske mostine.– in: marjanac, m. (ed.): 5. int. progeo symp. conserv. geol. heritage. rab, guideb. progeo croatia, zagreb, 37–77. mrinjek, e. & pencinger, v. (2008): excursion 3b, rab–split, the benkovac stone – a building stone from the promina beds: a late eocene succession of storm-dominated shelf deposits with highly diverse trace fossils.– in: marjanac, m. (ed.): 5. int. progeo symp. conserv. geol. heritage. rab, guideb. progeo croatia, zagreb, 105–125. mrinjek, e., pencinger, v., sremac, j. & lukšić, b. (2005): the benkovac stone member of the promina formation: a late eocene succession of storm-dominated shelf deposits.– geol. croat., 58, 163–184. nemec, w. & steel, r.j. (1984): alluvial and coastal conglomerates: their signifi cant features and some comments on gravelly mass-fl ow deposits.– in: koster, e.h. & steel, r.j. (eds.): sedimentology of gravels and conglomerates. can. soc. petr. geol., mem., 10, calgary, 1–31. nikler, l. (1982): značaj i karakteristike smeđih ugljena dalmacije [importance and characteristics of the lignites of dalmatia – in croatian, english abstr.].– geol. vjesnik, 35, 181–194. north american commission on stratigraphic nomenclature (nacsn) (1983): north american stratigraphic code.– am. assoc. petr. geol. bull., 67, 841–875. pavlovec, r. (1959): zgornjeeocenska favna iz okolice drniša [the upper eocene fauna from the surroundings of drnis in dalmatia – in slovenian, english summary].– dissertationes acad. sci. art. slov., ljubljana, 349–416. posamentier, h.w. & allen, g.p. (1993): siliciclastic sequence stratigraphic patterns in foreland ramp-type basins.– geology, 21/5, 455–458. posamentier, h.w. & allen, g.p. (1999): siliciclastic sequence stratigraphy-concepts and applications.– sepm concepts in sedimentology and palaeontology, 7/5, 204 p. prelogović, e., pribičević, b., ivković, ž., dragičević, i., buljan, r. & tomljenović, b. (2003): recent structural fabric of the dinarides and tectonically active zones important for petroleum-geological exploration in croatia.– nafta, 55/4, 155–161. quitzow, h.w. (1941): stratigraphisch-tektonische untersuchungen im norddalmatinischen alttertiär.– jahrb. reich. bodenforsch., 62, 422–437. sakač, k. (1961): geološka građa i boksitne pojave područja novigrad-obrovac u sjevernoj dalmaciji [kurze übersicht der geologischen structur und der bauxitvorkommen des gebietes novigradobrovac in dalmatien – in croatian, german summary].– geol. vjesnik, 14, 323–345. sakač, k. (1966): marinski fosili u boksitu dalmacije [marine fossils in bauxites of dalmatia – in croatian, english abstr.].– geol. vjesnik, 19, 131–138. babić and zupanič: laterally variable development of a basin-wide transgressive unit of the north dalmatian foreland basin... geologia croatica 27 sakač, k. (1970): analiza eocenskog paleoreljefa i tektonskih zbivanja u području drniša u dalmaciji s obzirom na postanak ležišta boksita [an analysis of the eocene paleorelief and tectonic events in the area od drniš, dalmatia, with regards to the formation of bauxite deposits – in croatian, english abstr.].– geol. vjesnik, 23, 163–179. sakač, k., benić, j., bahun, s. & pencinger, v. (1993): stratigraphic and tectonic position of paleogene jelar beds in the outer dinarides.– natura croat., 2/1, 55–72. savezni geološki zavod (federal geological institut) (1970): geološka karta sfr jugoslavije, 1:500000, beograd. schubert, r.j. (1904): das verbreitungsgebiet der prominaschichten im kartenblatte novigrad – benkovac (norddalmatien).– jahrb. geol. reichsanst., 54, 461–510. schubert, r.j. (1905): zur stratigraphie des istrisch-norddalmatinischen mitteleocäns.– jahrb. geol. reichsanst., 55, 153–190. schubert, r.j. (1908): geologische spezialkarte der osterreichischungarischen monarchie, 1:75000. novegradi und benkovac.– geol. reichsanstalt, wien. schubert, r.j. (1909): erläuterungen zur geologishen karte der österr.– ungar. monarchie novigrad–benkovac.– geol. reichsanstalt, wien, 1–26. shanley, k.w. & mccabe, p.m. (1994): perspectives on sequence stratigraphy of continental strata.– am. assoc. petrol. geol. b., 78/4, 544–568. siggerud, e.i.h., steel, r.j. & pollard, j.e. (2000): bored pebbles and ravinement surface clusters in a transgressive systems tract, sant llorenç del munt fan-delta complex, se ebro basin, ne spain.– sediment. geol., 138, 159–175. sinclair, h.d. (1997): tectonostratigraphic model for underfi lled foreland basins: an alpine perspective.– am. assoc. petroleum geol. bull., 109, 324–346. šikić, d. (1969): o razvoju paleogena i lutetskim pokretima u sjevernoj dalmaciji [über die entwicklung des paläogens und die lutetischen bewegungen in der nördlichen dalmatien – in croatian, german abstract].– geol. vjesnik, 22, 309–331. tucker, m.e. (2001): sedimentary petrology. an introduction to the origin of sedimentary rocks.– 3. ed. blackwell, oxford, 262 p. tucker, m.e. & wright, v.p. (1990): carbonate sedimentology.– blackwell, oxford, 496 p. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeogr., palaeoclimatol., palaeoecol., 220/3–4, 333–360. wilgus, c.k., hastings, b.s., kendall, g.st.c., posamentier, h.w., ross, c.a. & van wagoner, j.c. (1988): sealevel changes: an integrated approach.– sepm, spec. publ., 42, tulsa, 407 p. wright, m.e. & walker, r.g. (1981): cardium formation (upper cretaceous) at seebe, alberta – storm transported sandstones and conglomerates in shallow marine depositional environments below fair-weather wave base.– can. j. earth sci., 18, 795–809. zupanič, j. & babić, lj. (2011): sedimentary evolution of an inner foreland basin margin: palaeogene promina beds of the type area, mt. promina (dinarides, croatia).– geol. croat., 64/2, 101–119. manuscript received july 20, 2011 revised manuscript accepted january 18, 2012 available online february 25, 2012 geologia croatica 65/1geologia croatica 28 02_schlagintweit za web.indd 29 schlagintweit et al.: onset of an aptian carbonate platform overlying a middle-late jurassic radiolaritic-ophiolithic mélange in the mirdita zone of albania � ab stra ct late jurassic and early cretaceous carbonate sediments of different age and facies form the post-emplacement settings on top of the mirdita ophiolite zone in northern albania. they seal the early late jurassic emplacement of the ophiolite nappes, and are the only datable relics overlying the ophiolites. they aid evaluating the different tectonic movements associated with uplift and erosion as well as sea-level fl uctuations during that time span. these carbonates overlie ophiolite-derived clastics very often as shallowing-upward sequences. one of the largest shallow-water platforms is the mali i shenjtit platform, previously assigned to the barremian-aptian. a well-preserved section at the base of the platform can be ascribed to the early-late aptian based on orbitolinid foraminifera together with dasycladalean algae. this carbonate platform is the youngest preserved early cretaceous platform in albania, but was largely eroded away. late cretaceous shallow-water rudist limestones are widespread and preserved in the dinaride-albanide-hellenide realm directly above an eroded older basement. therefore, this aptian platform is very important for the reconstruction of the early cretaceous palaeogeography in the northwestern neotethyan realm. in addition, the stratigraphic ranges of characteristic aptian orbitolinid foraminifera, rectodictyoconus giganteus schroeder and mesorbitolina texana (roemer), are discussed on the basis of these results. keywords: mirdita ophiolite zone, platform carbonates, early cretaceous, neotethys realm onset of an aptian carbonate platform overlying a middle-late jurassic radiolaritic-ophiolithic mélange in the mirdita zone of albania � felix schlagintweit1, hans-jürgen gawlick2, richard lein3, sigrid missoni2 and lirim hoxha4 1 lerchenauerstr. 167, d-80935 munich, germany; (ef.schlagintweit@t-online.de) 2 department of applied geosciences and geophysics, chair of prospection and applied sedimentology, university of leoben, peter-tunner-strasse 5, a-8700 leoben, austria; (gawlick@unileoben.ac.at; s.missoni@ daad-alumni.de) 3 university vienna, center for earth sciences, althanstr. 14, a-1090 vienna, austria; (richard.lein@univie.ac.at) 4 empire mining albania (empire mining corporation) rruga perlat rexhepi, pallati unikon, kati i vi-te ap. 28, tirana, albania; (l.hoxha@yahoo.com) doi: 104154/gc.2012.02 geologia croatica 65/1 29–40 8 figs. zagreb 2012 geologia croaticageologia croatica 1. introduction and geological setting the onset of carbonate platforms in tectonically active mountain ranges like the albanides (fig. 1) plays an important role in the reconstruction of the evolution of orogenic belts. the mirdita zone in albania consists of obducted triassic-jurassic ophiolites, which derived, according to the triassic shelf arrangement, from the neotethys ocean further to the east (gawlick et al., 2008), comparable with the ophiolites in the dinarides (schmid et al., 2008; gawlick et al., 2009). for a different palaeogeographic interpretation see e.g.: robertson & shallo (2000), dilek et al. (2005); robertson et al. (2011). these ophiolites and the accompanying ophiolitic mélanges (radiolaritic-ophiolitic (wild-)fl ysch in the sense of gawlick et al., 2008), were overlain by several carbonate platforms of different ages, that sealed the emplacement of the ophiolite nappe stack and their obduction onto the apulian lower plate in oxfordian times. these platforms allow to reconstruct the post-emplacement history of the ophiolite nappes (e.g., ongoing tectonic movements, sealevel changes). the oldest proven platform is represented by the kimmeridgian-tithonian kurbnesh carbonate platform geologia croatica 30 geologia croatica 65/1 munella carbonate platform was established (peza & mar ku, 2002; gawlick et al., 2008) in a tectonically active regime (schlagintweit et al., 2008; robertson et al., 2011). the munella platform (e.g., in the regions of mali i munelles, mali i shenjtit – fig. 2) in addition to the younger mali i shenjtit platform, represents the only autochthonous early cretaceous shallow-water carbonate platform in the area of the mirdita zone, covering large areas in central albania. both platforms were originally seen as one platform and were dated by peza & marku (2002) and peza & zitt (2002) as barremian to aptian in age. gawlick et al. (2008) subdivided this platform into representing two stages of shallowwater carbonate deposition, the older munella carbonate platform (?late berriasian to valanginian) and the younger mali i shenjtit platform (?late barremian to aptian). like the late jurassic kurbnesh platform, the munella carbonate platform was eroded in most areas. the next carbonate platform was established after this deep erosion in ?barremian or aptian times (gawlick et al., 2008). nevertheless, the exact age of the onset of the mali i shenjtit platform has remained enigmatic, but is very important for the manifestation/correlation of tectonic events or sea-level fl uctuations in the whole dinaridic-albanide-hellenide realm. west of bulshari (fig. 2), the bathonian to oxfordian radiolaritic-ophiolitic (wild)fl ysch (mélange) (perlat formation: gawlick et al., 2008) and the overlying ?early cretaceous conglomerates are followed by the onset of the mali i shenjtit carbonate platform (fig. 3). at the base of the investigated section (fig. 4), directly on top of the mélange, a sequence of ophiolite-derived clastics (some tens of metres thick) is preserved (e.g., north of konaj: fig. 2). this succession is overlain by a marine carbonate succession with a preserved shallowing-upward sequence. this paper describes the early evolution of the youngest early cretaceous platform in albania together with new biostratigraphic and microfacies data. the results are important for the exact timing of ongoing tectonic movements in the dinaride-albanide mountain chain and to close a gap in knowledge of the age of the onset of different shallow-water carbonates above the mirdita ophiolite zone. 2. sedimentology, stratigraphy, and micropalaeontology 2.1. microfacies and micropalaeontology of the resediments the microfacies of the mass-fl ows are represented by different types of packstones with bioand lithoclasts of varying size and degrees of sorting. some clasts are close-packed with stylolitized contacts. this fi tted fabric corresponds to the stylobreccia fabric of logan & semeniuk (1976) (fig. 5a). sorting of the subangular clasts in these breccias is poor. the stylobreccia may directly overlie wackestones with dispersed larger lithoand bioclasts, mainly skeletons of stromatoporoids and small globigerinid and globigerinelloid foraminifera (fig. 5a–b, f). the stromatoporoids belong to two taxa, tubuliella fl uegeli turnšek (figs. 6i) and tubuliella (schlagintweit et al., 2008), which was eroded in early cretaceous (berriasian – valanginian) times. after erosion of the kurbnesh platform, the ?late berriasian-valanginian figure 1: a simplifi ed tectonic map of albania (after nowack, 1928; xhomo et al., geological map of albania 2002) and the study area. geologia croatica 31 schlagintweit et al.: onset of an aptian carbonate platform overlying a middle-late jurassic radiolaritic-ophiolithic mélange in the mirdita zone of albania figure 2: the mali i shenjtit carbonate platform and the munella carbonate platform (mali i munelles) in the northern/central mirdita zone. simplifi ed geological map on the basis of the harta gjeologjike e shqiperise 1 : 200.000 (xhomo et al., 2002), redrawn with the integration of the present results (after gawlick et al., 2008; schlagintweit et al., 2008). the studied section is located west of the village of bulshari. geologia croatica 32 geologia croatica 65/1 rotunda turnšek (fig. 6j), so far only known from the late jurassic of slovenia (turnšek, 1966), croatia (milan, 1969) and albania (schlagintweit et al., 2008). tubuliella is a typical representative of the so-called actinostromariid zone, characterizing the outer zone of late jurassic barrier-type reef complexes along shelf margins (turnšek, 1969; turnšek et al., 1981), thus explaining their resedimentation along a presumably rather steep slope, and their occurrence in the investigated mass-fl ows. the new aptian fi ndings also provide clear evidence that the two taxa have broad stratigraphic ranges. typical microencrusters such as radiomura cautica senowbari-daryan & schäfer (figs. 5c, 6b) and crescentiella morronensis (crescenti) (fig. 6a) also occur in accordance with the inferred original platform margin setting of the resedimented limestones. beside this, the packstones contain dasycladalean algae: triploporella sp., acroporella radoicicae praturlon (fig. 6d), linoporella/steinmanniporella sp. (fig. 6g) and steinmanniporella? parsica taherpour khalil abad et al. (fig. 6e, h). this taxon was described recently from the aptian of iran (taherpour khalil abad et al. 2010). higher up in the section, grainto rudstones occur with dasycladalean algae and orbitolinid foraminifera. the two taxa characterizing this interval are rectodictyoconus giganteus schroeder (fig. 7a–c) and mesorbitolina texana (roemer) (fig. 7d–f) being of importance for the biostratigraphic dating of the section (fig. 8). figure 3: a) field view of the mali i shenjtit carbonate platform overlying the jurassic radiolaritic-ophiolitic mélange, in the upper part with ?early cretaceous deep-water conglomerates. b) studied section north of mountain guri cicit showing a shallowing-upward sequence, which refl ects a prograding platform. 2.2. biostratigraphy discussion of the biostratigraphy of aptian strata, requires recognition that some authors use a bipartite division (bedoulian = early, gargasian + clansayesian = late aptian) (e.g., schroeder et al., 2010) while others prefer a tripartite division (bedoulian = early, gargasian = middle, clansayesian = late aptian) of the stage (e.g., castro et al., 2002; gradstein et al., 2004). masse (2003) additionally distinguished a lower ?early bedoulian (deshayesites tuarkyricus + d. weissi ammonite zones) and an upper ?late bedoulian (d. deshayesi + dufrenoya furcata ammonite zones). the stratigraphy of the studied section is based on orbitolinid foraminifera (e.g., schroeder, 1964, 1985; cherchi & schroeder, 1999; schroeder et al., 2002) (fig. 7a–f). supporting data are available from dasycladalean algae (e.g., granier & deloffre, 1993; bucur, 1999) and other benthic foraminifera. the two biostratigraphically most important taxa are rectodictyoconus giganteus schroeder (fig. 7a–c) and mesorbitolina texana (roemer) (fig. 7d–f). r. giganteus was described by schroeder (1964) from the urgonian of spain. zone ii with r. giganteus was considered to belong to the barremian. following zone i with palorbitolina lenticularis, (also characterizing zone iv of schroeder 1964), a late barremian age was originally assumed. in subsequent works, this age was corrected, with r. giganteus having its fi rst appearance (fad) in the earliest aptian (e.g., cherchi & schroeder, 1999; schroeder et al., 2002, fi g. 1; schroeder et al. 2010, fi g. 3). the total taxon range should be restricted to the lowermost part of the early aptian (bedoulian) (e.g., schroeder, 1964, fi g. 1; schroeder et al., 2010, fi g. 3). reviewing the literature, masse (2003), concluded that r. giganteus is a bedoulian marker and that data from spain suggests its essentially lower ?early bedoulian range. the taxon range zone of mesorbitolina texana is often indicated as late aptian (= clansayesian) to middle albian (schroeder, 1975, 1985; velić, 2007). a thorough analysis of different sections in spain with orbitolinids, planktonic foraminifera and ammonites (castro et al., 2002, fi g. 3) has shown, that m. texana reaches down to the upper part of the gargasian within the globigerinelloides algerianus planktonic foraminifera zone (= upper part of the parahoplites melchioris ammonite zone, compare fig. 6 in ropolo et al., 2008). in a new biostratigraphic scheme of barremian-albian orbitolinids, the fi rst occurrence of mesorbitolina texana is indicated as the middle part of the gargasian (base of the p. melchioris ammonite zone) (schroeder et al., 2010). our results are partly in contradiction to the generally accepted stratigraphic considerations according to schroeder (1964), that r. giganteus and m. texana or also m. parva (gargasian-lowermost clansayesian acc. to schroeder et al., 2010), should not display overlapping ranges. in the studied section, the basal part, up to sample al 972 only contains r. giganteus, followed by an interval (~ 17 m) where r. giganteus co-occurs with m. texana in the same thin-sections (al 972 to al 980) (see fig. 4). as the two species occur as both isolated bioclasts, and within lithoclasts that have been contemporaneously resedimented, reworking geologia croatica 33 schlagintweit et al.: onset of an aptian carbonate platform overlying a middle-late jurassic radiolaritic-ophiolithic mélange in the mirdita zone of albania figure 4: detailed section, biostratigraphy and microfauna and -fl ora content. geologia croatica 34 geologia croatica 65/1 figure 5: microfacies of the aptian resediments. a – wackestone with some lithoand bio-clasts (here: stromatoporoid skeleton), overlain by a closepacked mass-fl ow of stylo-breccia or diagenetic packstone habitus (sensu logan & semeniuk 1976). note the dark layer of styloreactate at the boundary. sample a 3744. b – wacketo packstone containing globigerinid planktonic foraminifera (p) overlain by a grainto rud-stone with bioclasts of calcareous algae and metazoan skeletons. sample a 3755-2. c – packstone with incertae sedis radiomura cautica senowbari-daryan & schäfer (ra), crescentiella morronensis (cresecenti), diverse bioclasts and tests of rectodicytoconus giganteus schroeder (re). sample a 3741. d – mass-fl ow consisting of close-packed clasts containing dasycladalean algae and tests of rectodictyoconus giganteus schroeder (re). sample al 976. e – well washed-out packstone with dasycladalean algae, (d), mesorbitolina texana (roemer) (m) and rectodictyoconus giganteus schroeder (re). sample a 3746-1. f – massfl ow deposit with skeleton of the stromatoporoid tubuliella rotunda turnšek. sample al 990. for a scale bar is 5.0 mm; for b–f scale bar is 2.0 mm. geologia croatica 35 schlagintweit et al.: onset of an aptian carbonate platform overlying a middle-late jurassic radiolaritic-ophiolithic mélange in the mirdita zone of albania figure 6: microproblematica (a–c), dasycladalean algae (d–h) and stromatoporoids (i–j) from the studied section. a) crescentiella morronensis (crescenti). sample a 3741. b) radiomura cautica senowbari-daryan & schäfer. sample a 3741. c) koskinobullina socialis cherchi & schroeder. sample a 3743. d) acroporella radoicicae praturlon. sample a 3741. f) salpingoporella pygmaea (gümbel). sample a 3745. g) linoporella sp. sample a 3745. e, h) steinmanniporella? parsica taherpour khalil abad et al. sample a 3753. i tubuliella rotunda turnšek. sample a 3744. j) tubuliella fl uegeli turnšek. sample a 3748. for a, c–h scale bar is 0.5 mm; for b, i–j scale bar is 1.0 mm. geologia croatica 36 geologia croatica 65/1 figure 7: middle-late aptian foraminifera from the studied section. a–c) rectodictyoconus giganteus schroeder. note the centric embryonic apparatus in c; subaxial section of lenticulina sp. on the right. samples a 3748, al 976, a 3476. d–f) mesorbitolina texana (roemer). samples a 3753, al 976, g–h) planispial globigerinelloides sp., comparable to section of g. algerianus in sliter (1989, pl. 1/13). samples a 3753, a 3752. i) trochospiral globigerinid foraminifer. sample a 3753. j) globigernid planktonic foraminifer (pf) and sabaudia minuta (hofker) (s). sample a 3753. for a–b, f scale bar is 1mm; for c–e, g–j scale bar is 0.5 mm. geologia croatica 37 schlagintweit et al.: onset of an aptian carbonate platform overlying a middle-late jurassic radiolaritic-ophiolithic mélange in the mirdita zone of albania son et al. (2011, fi g. 6/11), however, does not allow a conclusion to be drawn in this respect. therefore, this section could also belong to r. giganteus in accordance with our results from northern albania. according to henson (1948), the dimensions of dictyoconus (= montseciella) arabicus are: test diameter 2.4 to 3.2 mm and height 1.7 to 2.0 mm. for rectodictyoconus giganteus schroeder (1964) indicated a test diameter from 4-5 mm and height of 3-4 mm. juvenile specimen of r. giganteus, clearly evidenced by the central embryo in our material (fig. 7c, compare also fig. 4a-4 in schroeder et al., 2010), however falls into the dimensional range of m. arabica, so that the pure dimensional discrimination of both taxa remains ambiguous. the situation becomes more complicated as microspheric specimens of m. arabica may reach test diameters of up to 6 mm (fig. 4b-7 in schroeder et al., 2010). another point to mention is the fact that no holotype has been indicated for r. giganteus in the original description. another example refers to the paper of marroni et al. (2009), which deals with early cretaceous fl yschoid deposits in northern albania. these authors report the occurrence of paleodictyoconus arabicus (= montseciella arabica) in turbidite deposits, assigning these, also based on calcareous nannoplankton data, to the barremian. the fi gured oblique section of paleodictyoconus arabicus in marroni et al. (2009, fi g. 6e) however, does not belong to this taxon. the typical vermicular structural elements in the central zone are absent, and this orbitolinid could be a fl at discoidal specimen of mesorbitolina or palorbitolina without allowing a species attribution, as the embryonic apparatus is not shown. in any case, a barremian age based on this orbitolinid section alone is not possible; but we cannot comment on the nannofossil determination. a third example comes from the vardar zone of serbia, where “paleodictyoconus arabicus” was reported by zelic et al. (2010, fi g. 5c). furthermore, this oblique section of an orbitolinid foraminifer belongs to palorbitolina or mesorbitolina. last but not least, an undetermined orbitolinid that we refer to as an oblique section of either m. arabica (henson) or r. giganteus schroeder was fi gured by carras et al. (2004: pl. 1, fig. f) from the pelagonian unit of greece. it occurs in resedimented carbonates assigned to the cenomanian, assuming of older material/clasts seems unlikely. the middle-upper part of the studied section contains only m. texana. given these results (castro et al., 2002; schroeder et al., 2010), the stratigraphic range of r. giganteus must be enlarged, comprising at least the late gargasian. an extension into the earliest clansayesian seems possible. a possible reason that both taxa are clearly separated at the type-locality of r. giganteus might be related to a facies control, as its latest occurrence shows a distinct contemporaneous lithological change from limestones to marls/marly limestones (see fi g. 1 in schroeder, 1964). in contrast to mesorbitolina texana with its numerous records in the literature, rectodictyonus giganteus represents a rather poorly known taxon, which may account for the limited knowledge of its stratigraphic distribution (see masse, 2003). although determination of globigerinelloides in thinsection is problematic (e.g., weidich, 1990), we have to state that our specimens within an interval from sample a-3752 to a-3753 (fig. 7g-h) are comparable to a section of g. algerianus illustrated by sliter (1989, pl. 1/13). this species characterizes the g. algerianus zone (moullade, 1966; sliter, 1989; castro et al., 2002). in summary, the studied section is of aptian age, assumed to comprise parts of the bedoulian (early aptian) and ranging into the clansayesian (late aptian) (fig. 8). whether the top part stretches into the early albian is unknown. as only an 18 m thick sequence below the fi rst occurrence of mesorbitolina texana exists, extension of the section into the late barremian is not very likely. the associated dasycladalean algae are also compatible with an aptian age (e.g., bucur, 1999; taherpour khalil abad et al., 2010). it is worth mentioning that for the carbonate platforms overlying the ophiolites and cropping out in northern albania, an overall late barremian-early aptian age has been deduced from micropalaeontological investigations, namely the occurrence of montseciella arabica (henson) (robertson et al., 2011, tab. 1). as stated by cherchi & schroeder (1999, p. 13), montseciella arabica “grades into rectodictyoconus giganteus” during the basal aptian. r. giganteus differs from m. arabica by “the centric position of the embryo and its generally larger test” (op. cit., p. 13). the oblique section of “m. arabica” shown by robertfigure 8: stratigraphic framework of the studied section (modifi ed after castro et al., 2002). the fi rst appearance of mesorbitolina texana (roemer) at the base of the melchioris ammonite zone refers to schroeder et al. (2010). geologia croatica 38 geologia croatica 65/1 “an hiatus including the whole early cretaceous” (op. cit., p. 353). this situation generally mirrors the situation in albania, where fi rstly a late jurassic carbonate platform overlies the ophiolites, later followed by several emersion phases and at least a late cretaceous series. whether the early cretaceous orbitolinid in the greek case study was reworked from older sediments or whether the age of the “late cretaceous” series must be re-assessed is unknown. in conclusion, stratigraphic data obtained from orbitolinid foraminifera from sediments associated with dinaric ophiolites reported in the literature, (with or without fi guration), must be considered with caution, especially when these determinations are coupled with dating of tectonic or sedimentary events. 3. discussion and conclusions after the obduction of the mirdita ophiolites onto the apulian margin in early late jurassic times, subsequent shallowwater carbonates were formed overlying the ophiolite nap pes. the fi rst platform, of kimmeridgian-tithonian age (kurbnesh platform), was eroded before the onset of the second platform in ?late berriasian times. the late jurassic platform can only be recognized by preserved late jurassic basinal deposits (slope sediments) and their erosional products in earliest cretaceous foreland basin fi lls (schlagintweit et al., 2008). in-situ platform areas of late jurassic age overlying the ophiolites, are not preserved on top of the mirdita ophiolites. in contrast, the second platform of ?late berriasian to valanginian age (munella platform) is partly preserved in central albania. however the type-locality, the mali i munelles, is highly sheared and the platform carbonates are imbricated (schlagintweit et al., 2006). contemporaneous coarse-grained foreland basin fi lls, contain clasts of the munella platform (schlagintweit et al., 2008). both platforms were therefore formed under a tectonically active regime after ophiolite emplacement. after a period of erosion/omission until the late barremian, a new cycle of carbonate deposition began in the early aptian, at the top of the deeply eroded mirdita nappe pile and its overlying late jurassic and early cretaceous carbonate platforms. the formation of the aptian mali i shenjtit carbonate platform most probably began in the early aptian and not in the barremian as formerly estimated. in contrast to the older platforms, the sedimentary succession of this platform is not sheared and its layering is fl at. after formation of this platform, tectonic movement, most probably the formation of a horst-and-graben structure, must have been established before deposition of the late cretaceous (rudist) limestones. the onset of the mali i shenjtit platform and the total thickness of the fl at lying shallow-water carbonates up-section, clearly demonstrate a fl ooding event, triggered more probably by eustatic sea-level changes rather than important tectonic movements. an important sea-level rise is known near the base of the aptian (e.g., gradstein et al., 2004), followed by a regression near the end of the aptian. this fi ts well with the age range of the mali i shenjtit platform, which does not extend beyond the aptian. on basis of the analysis of the foreland basin fi lls and their generally recognizable fi ning-upward trend (e.g., bortolotti et al., 1996: “firza flysch”), as well as complete erosion of the oldest and the imbrication of the second platform, gawlick et al. (2008) considered a decrease in tectonic activity from the late jurassic to the early cretaceous. the fl at lying aptian shallow-water carbonates fi t into the trend, that platform formation in late jurassic to early cretaceous times become more and more controlled by sea-level fl uctuation rather than tectonic motion. this was recently confi rmed in general by robertson et al. (2011). the onset and demise of the late jurassic carbonate platforms after the emplacement of the ophiolite nappe stack in the oxfordian refl ect a decrease in tectonic activity from the kimmeridgian to the aptian. whereas the fi rst platform (kimmeridian – tithonian) was rapidly eroded after its formation, most probably as the result of the ongoing tectonic shortening, (compare schmid et al., 2008), and also documented by thick foreland basin deposits, the second platform (?late berriasian-valanginian) was formed in a tectonically active regime, but one of decreasing intensity. the younger sedimentary evolution refl ects deposition in a regime, which was more imprinted by eustatic sea-level fl uctuations than tectonics. the aptian carbonate platform was formed in a phase of relative tectonic quiescence before a new tectonic cycle (?late albian/cenomanian) began. only these younger tectonic motions – faulting and thrusting -, e.g. in meso-cretaceous, palaeogene and/or neogene times, affected this platform together with its underlying rocks. as a result of the pre-late cretaceous faulting, the mali i shenjtit platform become eroded over large areas and the ophiolites, particularly the ophiolite mélanges were overlain by early late cretaceous rudist limestones. acknowledgement the joint projects ‘‘tectonothermal evolution of the albanides 2003–2005’’ and “emplacement of the copper ore deposits 2006-2007” received fi nancial support from: albanian government (geological survey of albania); university of leoben, university of vienna, austrian academic exchange service, all austria; university of tübingen, germany. the careful reviews of ioan bucur (cluj-napoca) and anonymus are gratefully acknowledged. the assistance with the english of julie robson is kindly acknowledged. references bortolotti, v., kodra, a., marroni, m., mustafa, f., polfi, l., principi, g. & saccani, e. (1996): geology and petrology of ophiolite sequences in the mirdita region (northern albania).– ofi oliti, 21/1, 3–20. bucur, i.i. (1999): stratigraphic signifi cance of some skeletal algae (dasycladales, caulerpales) of the phanerozoic.– in: farinacci, a. & lord, a.r. (eds.): depositional episodes and bioevents. palaeopelagos spec. pub., 2, 53–104. carras, n., fazzuoli, m. & photiades, a. (2004): transition from carbonate platform to pelagic deposition (mid jurassic-late cretaceous), vourinos massif, northern greece.– riv. ital. paleont. strat., 110/1, 345–355. geologia croatica 39 schlagintweit et al.: onset of an aptian carbonate platform overlying a middle-late jurassic radiolaritic-ophiolithic mélange in the mirdita zone of albania castro, j.m., company, m., de gea, g.a. & aguado, r. (2001): biostratigraphy of the aptian-middle cenomanian platform to basin domain in the prebetic zone of alicante, se spain: calibration between shallow water benthonic and pelagic scales.– cret. res., 22, 145–156. doi: 10.1006/cres.2000.0249. cherchi, a. & schroeder, r. (1999): montseciella, a new orbitolinid genus (foraminiferida) from the uppermost hauterivian – early barremian.– treb. mus. geol. barcelona, 8, 5–23. dilek, y., shallo, m. & furnes, h. (2005): rift-drift, seafl oor spreading, and subduction tectonics of albanian ophiolites.– international geology review, 47, 147–176. doi: 10.2747/0020-6814. 47.2.147 gawlick, h.j., frisch, w., hoxha, l., dumitrica, p., krystyn, l., lein, r., missoni, s. & schlagintweit, f. (2008): mirdita zone ophiolites and associated sediments in albania reveal neotethys ocean origin.– int. j. earth sci., 97, 865–881. doi: 10.1007/ s00531-007-0193-z gawlick, h.-j., missoni, s., schlagintweit, f., suzuki, h., frisch, w., krystyn, l., blau, j. & lein, r. (2009): jurassic tectonostratigraphy of the austroalpine domain.– journal of alpine geology, 50, 1–152. granier, b. & deloffre, r. (1993): inventaire critique des algues dasycladales fossiles ii partie – les algues dasycladales du jurassicssique et du crétacé.– rev. paléobiol., 12, 19–65. logan, b.w. & semeniuk, v. (1976): dynamic metamorphism; processes and products in devonian carbonate rocks, canning basin, western australia.– geol. soc. australia spec. pub., 16, 1–138. marroni, m., pandolfi, l., onuzi, k., palandri, s. & xhomo, a. (2009): ophiolite-bearing vermoshi fl ysch (albanian alps, northern albania): elements for its correlation in the frame of dinaric-hellenic belt.– ofi oliti, 34/2, 95–108. masse, j.-p. (2003): integrated stratigraphy of the lower aptian and applications to carbonate platforms: a state of the art.– in: gili, h.n. & skelton, p.w. (eds.): north african cretaceous carbonate platform systems, nato science series, iv. earth and environmental sciences, 28, 215–227, kluwer academic publishers. milan, a. (1969): faziesverhältnisse und hydrozoenfauna des malms im küstenland des nördlichen velebit und velika kapela.– geol. vjesnik, 22 (1968), 201–219. moullade, m. (1966): étude stratigraphique et micropaléontologique du crétacé inférieur de la « fosse vocontienne ».– doc. lab. géol. fac. sci. lyon, 15, 1–369. nowack, e. (1928): geologische karte von albanien 1:200.000.– verlag kartographisches institut wien. gradstein, f., ogg, j. & smith, a. (2004): a geological time scale.– cambridge university press, cambridge, 1–589. peza, l.h. & marku, d. (2002): lower cretaceous in the munella mountains (mirdita zone, northeastern albania).– in: wagreich, m. (ed.): aspects of cretaceous stratigraphy and palaeobiogeography. österr. akad. wiss., schriftenr. erdwiss. komm., 15, 365–372. peza, l.h. & zitt, j. (2002): urgonian (early cretaceous) echinoids of the mirdita zone (southeast albania).– geol. carpath., 53/5, 327–332. robertson, a. & shallo, m. (2000): mesozoic-tertiary tectonic evolution of albania in its regional eastern mediterranean context.– tectonophysics, 316, 197–254. doi: http://dx.doi.org/10.1016/s0040 1951(99)00262-0 robertson, a.h.f., ionescu, c., hoeck, v., koller, f., onuzi, k., bucur, i.i. & ghega, d. (2011): emplacement of the jurassic mirdita ophiolites (southern albania): evidence from associated clastic and carbonate sediments.– int. j. earth sci. doi 10.1007/s00531-010-0603-5 ropolo, p., conte, g., moullade, m., tronchetti, g. & gonnet, r. (2008): the douvilleiceratidae (ammonoidea) of the lower aptian historical stratotype area at cassis-le bédoule (se france).– carnets de géologie mem. 3 (cg2008_m03) schlagintweit, f., gawlick, h.j., missoni, s., lein, r. & hoxha, l. (2006): late jurassic to early cretaceous dasycladales and benthonic foraminifera from the munella carbonate platform s. l. of the mirdita zone (albania).– in: sudar, m., ercegovac, m. & grubic, a. (eds.): proceedings xviiith congress of carpathian-balkan geological association), 527–530, (national committee of the carpathian balkan geological association; serbian geological society) belgrade. schlagintweit, f., gawlick, h.j., missoni, s., hoxha, l., lein, r. & frisch, w. (2008): the eroded late jurassic kurbnesh carbonate platform in the mirdita ophiolite zone of albania and its bearing on the jurassic orogeny of the neotethys realm.– swiss j. geosci., 101, 125–138. doi: 10.1007/s00015-008-1254-4 schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine-carpathian-dinaride-orogenic system: correlation and evolution of tectonic units.– swiss j. geosci. (eclogae geol. helv.), 101, 139–183. doi: 10.1007/s00015-008-1247-3 schroeder, r. (1964): orbitoliniden-biostratigraphie des urgons nordöstlich von teruel (spanien).– n. jb. geol. paläont. mh., 1964, 462–472. schroeder, r. (1975): general evolutionary trends in orbitolinas.– rev. esp. micropaleont., num. spec., 117–128. schroeder, r. (1985): orbitolina (m.) texana (roemer, 1849).– in: schroeder, r. & neumann, m. (eds.): les grands foraminifères du crétacé moyen de la région méditerranénne. géobios mém. spéc., 7, 77–80. schroeder, r., clavel, b., cherchi, a., busnardo, r., charollais, j. & decrouez, d. (2002): lignées phylétiques d´orbitolinidés de l´intervalle hauterivien supérieur – aptien inférieur; leur importance stratigraphique.– rev. paléobiol., 21, 853–863. schroeder, r., van buchem, f.s.p., cherchi, a., baghbani, d., vincent, b., immenhauser, a. & granier, b. (2010): revised orbitolinid biostratigraphic zonation for the barremian – aptian of the eastern arabian plate and implications for regional stratigraphic correlations.– geoarabia spec. pub., 4, 49–96. sliter, w.v. (1989): biostratigraphic zonation for cretaceous planktonic foraminifers examined in thin section.– j. foramin. res., 19, 1–19. doi: 10.2113/gsjfr.19.1.1 taherpour khalil abad, m., conrad, m.a., aryaei, a.a. & ashouri, a.r. (2010): barremian-aptian dasycladalean algae, new and revisited, from the tigran formation in the kopet dagh, ne iran.– carnets de géologie – notebooks on geology, article 2010/05 (cg2010_a05) turnšek, d. (1966): upper jurassic hydrozoan fauna from southern slovenia.– razprave razr. sazu, 9, 335–428. turnšek, d. (1969): a contribution to the palaeoecology of jurassic hydrozoa from slovenia.– razprave razr. sazu, 12, 209–237. turnšek, d., buser, s. & ogorelec, b. (1981): an upper jurassic reef complex from slovenia, yugoslavia.– sepm spec. pub., 30, 361–169. velić, i. (2007): stratigraphy and palaeobiogeography of mesozoic benthic foraminifera of the karst dinarides (se europe).– geol. croat., 60, 1–113. weidich, k.f. (1990): die kalkalpine unterkreide und ihre foraminiferenfauna.– zitteliana, 17, 1–312. xhomo, a., kodra, a., dimo, ll., xhafa, z., nazaj, sh., nakuçi, v., yzeiraj, d., lula, f., sadushi, p., shallo, m., geologia croatica 40 geologia croatica 65/1 vranaj, a. & melo, v. (2002): harta gjeologjike e shqiperise, geological map of albania, scale 1:200,000, published by the ministry of industry and energy, republic of albania. zelic, m., marroni, m., pandolfi, l. & trivić, b. (2010): tectonic setting of the vardar suture zone (dinaric-hellenic belt): the example of the kopaonik area (southern serbia).– ofi oliti, 35/1, 49–69. manuscript received may 04, 2011 revised manuscript accepted november 15, 2011 available online february 25, 2012 geol. c roat . 50/2 1 151 . 155 1 i zagreb 1997 professor herak's contribution to triassic stratigraphy georg koch and tonci grgasovic abstract the beginning of prof. herak's sc ientific career was linked to (he problems of the triass ic stratigraph y. he resolved the triassic stratig­ raphy o f some parts of the croatia n dinaridcs by using dasyclad algae. sazetak pocelak karijere pro fes ora milana heraka bio je vczan za pro­ blernatiku stratigrafije trijasa. stratigrafiju trijasa pojedinih dijelova hrvatskih dinarida ljdavao jc korislcci daziklndalnc algc. "the triassic within the dinarides is very well developed, thus representing a very important part of the mediterranean triassic" (herak, 1984, p. 205) professor herak 's scientific work can be divided into a tripartite, informal chronological division: "early herak" comprises the work on triassic problems, "mi­ ddle herak" incl udes the research on karst phenome­ non and " late herak " charac terises the effort to con­ tri ve a proper structural and geodynamic model of the dinarides. the "early herak" period lasted approximately thir­ ty years and it seems to be that herak owes his interest in the triass ic to the geological work undertaken within the research team of pro fesso r salopek, and also possi­ bly to his subsequent phd studies, guided by julius von pia in vienna (herak, 1943, 1944). his first stratigraphic work (herak, 1947) dea ls with the stratigraphic division of the mesozoic deposits of his native zumberak mt. area. in a series of publica­ tions (herak, 1954a, b, 1955) , he reported on the geo logy of the neighbouring samobor mountain. sub­ sequently, he published his significant work "geology of the samobor mountain" (h erak, [956a) in which very detailed descript ions on the stratigraphic and tec­ tonic relationships were given, especially for the trias­ sic. his research showed clearly tha t the distribution of the tri ass ic within the inves ti ga ted area was much more extensive than was earlier presumed, and for the gypsum deposits, previously attributed to the early tri­ assic, he indicated palaeozoic age. [-ie also dittcrenti­ atcd the middle triassic (ladinian), mixed shale-marlinstitu[e of geology, saehsova 2. p.o. box 268, hrioooo zagreb, croati a. limestone successions, with tuffs and chcrts, as well as the late triassic dolomites . the widespread carbonate successions of the zumberak mountain were also proven to be late triassic in age (herak et ai., 1965). the lates t paper on the triassic from his native zumbe­ rak, date [rom the end of the 1960 's (herak, 1966c, 1968). nevertheless, he is nowadays still connected 10 the zumberak stratigraphy as a referee on the main pro­ ject of the geo[ogiea[ map [:50,000 of the repub[ic of croatia. within the regional fram ework of geological research, herak investigated the area of kordun and lika (herak, [954e, 1956c). there, in the area of the korana river, he di scovered wid espread triassic deposits, especially dolomites, overlain by the early jurassic (liassic) dolomites. subsequently, herak & bahun ( [963) and herak & bolanic (1966) investigated the triassic in greater detail, proving that this area is characterized by early and late triassic suc­ cessions. in a series of publications (herak, 1952a, b, 1956a, 1957, 1962, 1963 , 1966b, 1968; herak & bahun, [963; herak & bojanic, [966), herak uses the "algae" sphaerocodium borjlemal1j1i as proof of the identification of late triassic deposits. although it was later proven that such findings are not "algae" but sedimento[ogiea[ structures· oneoids (babic, j 970), the deposi ts characterized by oncoids remain during the geological mapping as an indicator of late triassic this paper was presented at the scientific meeting dedicated to the 80th anniversary of the life of professor milan herak, held on march 5th, 1997 in zagreb i)", deposits, where these oncoids often occur in high num­ bers. herak ( 1950) pointed ou t the great significance of the use of dasyc1ad algae in the division of thc triassic successions, linking through this approach his two research fields. in the area of gracac, herak (1956b) separates the anisian from the ladinian deposits on the basis of their dasyclad flora, and proved the discontinu­ ity bctwcen the ladin ian and carnian. in the same area, herak (1960c) identified the disconti nuity between the permian and the triassic, proved the middle trias­ sic, and complcted thc interpretation of the discontinu­ it y bctween the middle and late triassic. having investigatcd the triassic in the vicinity of sv. rok in lib, herak (1965) confirmed once more the great value of the dasyc1ad algae in the stage division of the middle triassic, and revised some of the known stra ti ­ graphic ranges or certain species. herak synthesised his knowledge and that of other geologists and he presented it rcgularly at home as well as to the world-wide scientific community. the triassic stra ti graphy of croatia, based on the dasyclad algae (herak, 1960b), was presented for the first time to the world-wide geological community at the interna­ tional geological congress in copenhagen. at the international colloquium on the triassic in montpellier in 1961, herak (1962,1963) showed the main bio­ stratigraphic, lithological and palaeogeographical rela­ tionships of the triassic in croatia, emphasising the role of certain orogenic phases on the formation of the triassic successions and their final distribution. in the lecture, held in thc vienncse geological society, her­ ak (1966a) emphasized the role of dasyclad algae in the stratigraphy of thc dinarides. at the slovakian international colloquium on the triassic stratigraphy, herak et al. (1967) presented a correlation of the tri­ assic or lika, paklcnica and gorski kotar , with the revicw of thc fossil dasyclad assemblage. subsequently, herak ( 1973b) presented the resu lts of the investiga­ tion of the triassic in croatia, and in herak (1987b) a review of thc triassic of the dinarides in the light of thc transition between hercynian and alpine orogenic phases. at the viennese international symposium on the alpine-mediterranean triassic stratigraphy, herak (1974a) gave a precis of the results of h is work on the research of the triassic in the dinarides, with the emphasis on the palaeogeography and facies. by doing this, he highlighted the problems which remain topical today: "the palaeogeographic conditions of the facies development during triassic of a relatively narrow belt of the croatian dinarides, rel-leet the dynamics without any clear chronolog ical or facies overlapping of the bordcring layers of different stages and series. conse­ quently, the use of chronostratigraphic units in the stratigraphi c class ification is morc difficult and more or less artificial. therefore, lithostrat igraphic units have the advantage of application, bccause they better reflect the natural mutual relations. in these cases, the chronoijcologw lroalica )u/l. strat igraphic uni ts arc treated generally and morc or less dynamically . every attempt of squeezing that kind of dynamics into a virtual static frame, would represent suppressing of the natural relationships". at the viennese symposium on the biostratigraphy of the tethyan triassic, herak et al. (1983) presented the proposal for the stratotype of the european upper scythian in the area of mue. this is one of the undoubt­ edly mosl significant contributions to the triassic stratigraphy, which is evidenced in the generally high intcrcst among the triassic researchers. herak is also connected through his educational work as an university professor of stratigraphical and regional geology to his research field of triassic strati­ graphy. on this issue, he wrote a lot in his university textbooks (herak, 1960a, 1973a, 1984, 1987a, 1990; tajder & herak , 1951, 1959, 1966). he contri­ buted also in resolving some of the general stratigraphic problems (herak, 1974b, 1975, 1976), whieh made him one of the most important advisors in the realisa­ tion of the new geological map of croatia. lei us conclude that professor herak 's contribution to triassic stratigraphy is exceptional, by emphasising his approach of the application of the dasyclad algae to the stratigraphy, and the synthcsis of the knowledge on facies and palaeogeographic development of the trias­ sic in croatia. references babic, lj. (1970): sphaerocodiu/ji or oncoids from the upper triassic dolomi te of wcstcrn yugoslavia? (sphaerocodium iii onkoidi iz gornjotrijaskog dolomita zapadnog dijela jugoslavije?).geoloski vjesn ik, 23 (1969), 11 -19. herak, m. (1943): zur kenntnis triadischer kalk­ schwamme (sycones).n. jb. min. geol. pal aeon!., abh., b, 88,107-135. herak, m. (1944): triaskc vapnenc spuzvc iz skup ine "sycones" (triadischer kalkschwamm e aus del' gruppe "sycones") .vjesnik hrvatskog drzavnog geolozkog zavoda, 2-3, 41-70, zagreb. herak, m. (1947): prilog stratigrafskom rasclanjiva­ nju mezozoj skih naslaga jugozapadnog dijcla zum­ berackc gore.geoloski vjesnik, 1,3-5. herak , m. (1950): ladinicke dasycladaceae .lugo­ slavije i njihovo stratigrafsko znacenje.racl jugo­ slavenskc akadcmije znanosti i umjetnosti, 280, 115-14l , zagreb. herak, m. (1952a): znacenje alge sphaerocodium bornemanlli rothplctz za interpretaciju gornjeg tri­ jasa u podrucju zagorske mreznice.rad ju go­ slavenske akademije znanosti i umjetnosti, 289/4, 187 -195, zagreb. herak, m. (l952b): die bedeutung del' alge spliae­ roeodillljl bornemann! rothpletz flir die interprctakoch & grgasovic: professor ilerak·s contribution to tri;lssic sir:ui graphy lion del' oberlri as im gebiet von zagorska mrezni­ c;.l. bul letin se icntifiqu c, consci l des academics des sc iences ct dcs a rts de la r.s .f. de yougo­ slav ic, section a: sciences naturelles, techniques et medicales, 7, 85-88, zagreb. herak, m. (1954a): izvjcstaj 0 geoloskom istraz iva­ nju samoborske gore ii godi ni 1951.ljctopis jazu , 59 (1951 1952), 81-83, zagreb. l-liorak, m. ( 1954b): izvj cstaj 0 geo loskim istrai iva­ njima u samoborskoj okolin i u god ini 1952.ljc­ topis jazu, 59 (195 1-1952), 84-86, zagreb. ll era k, m. (1954e): 0 geoloskim prilikama pod rucja korane uzvodno od slunja cobcr die geologischen verhiilt llissc des korana gebicles von slunj in kro­ ati en). geolosk i vjesn ik, 5-7 (195 11953), 7 -24. il era k, m. ( 1955): geoloska istrazivanja u podrucju samoborske gore.ljelopis jazu, 60 (1953), 279280, zagreb. iierak, m. (1956a): geologija samoborskog gorja (geo log ie des samoborer gcbirge).acta geo lo­ gica, 1,49-73 , zagrcb. i ierak, m. (1956b): st ratig rarska intcrpretaeija tri ­ jaskih sed imcnata s dasikladaeejam<1 u okolici gracaca u hrvatskoj (s trat igraphische interpretation triadischer sed imentc mit dasycladaccen cler um­ gebung von gracac in kroatien).acta geologica, i , 149154, zagreb. herak, m. (19560): 0 mezozo iku pudrucja koranc izllledu barilovica i poloja (uber das mesozoikum des korana gcbiclcs zwischen ba ri lov ic li nd pol­ oj).gcolosk i vjcsnik, 8-9 ( 19541955),53-66. lierak, m. (1957): nov i nalazi s ferokod ij a u i-irvat­ skoj i slovcniji (neue funclc von sph{f('rococ/iuli/ in kroaticn lind siowenicn) .gcolosk i vjesn ik, 10 ( 1956), 3 i -38. herak, m. (1960a): geologija. struktura, dinamika i ili storija zelllljc.skolska knj iga, zagreb, x i+433 p. herak , m. (1960b): calcareous a lgae of the young palacozoic and mesozo ic of yugosl avia and thei r application in the stratigraphy.in: hessland, i. & erotman, g. (cds .): report o f the twe nt y­ firs t session, norden, i nternational geolog ical congress. part vi , proceed ings of section 6, pre­ quaterna ry micropaleontology. det berlingskc bogtrykkeri, 90-97 , copenhagen. herak, m. ( 1960e): geologija gracackog polja u liei (geologie des karst poljc von gracac in def lika, kroatien).gcoloski vjesnik, 13 (1959), 3 1-56. iierak , m. (1962): trias de la yugoslavie.geoloski vjesnik, 15/1,301 -3 10. fierak , m. ( 1963): trias de yugoslavie. in : le tri as de la france et des region s limitrophes. mem. i3meau reeh. geol. min., 15,477-454, paris. 153 herak, m. (1965): nas lagc trijasa u okolici sv . roka ii lici (triasablagcrungen in def umgebung von sv . rok in der lika).ac ta geologica, 5, 85 100, zag­ reb. h erak, m. (l966a) : die kalkalgen in de l' strati gra­ phic cle f dinariden (jungpab\ozo ikum linci mcso­ zoik ul11). mi tteilungen der geologischen gescll­ sehaft in wien, 58 , 209-217, wien. herak, m. (1966b) : geolosko istraz ivanj e zumbe r­ ka.ljetopis jazu, 7 1 (1964),263-265, zagreb. herak, m. ( 1968): noviji rczultat i istrai.ivanja osnov­ nih stratigrafskih jcd inica u zumbcrku (neu ergeb­ nisse der untersuchungen von st ratigraphi sc hen haupteinhcitcn in zumberak (w kroat ien)). gco­ loski vjcsn ik, 21 ( 1967), 11 1-1 16. h erak , m. (1973a): geologija. st ruk tura, din::lmika i razvoj zemlje.2nd cd., skoiska knjiga, zagreb, xii+465 p. her ak, m. (l973b): novija is trazivanj a trij asa u i-l rvatskoj (neuerc untersuchungen der t rias kroat­ iens).geologija, 16,375-378, ljubljana. h erak, m . ( 1974a): pal iiogeographie li nd fazi es­ en twick lung withrc nd der t rias in den di nar idcn kr03tiens.i n: zapfe, h. (eel): die stratigraph ic clef alpi n-medi lerrancn tri as. symposium (wicn, mai 1973) . osterre ichische akademie der w is­ sc nsc haften, schriftenreihe der erdwissellscha n­ lichen kolllmi ssionen, 2, 101 106, w icn. herak , m. (i974b): prineipi stratigrafske klas irika­ cije i tcrm inologije (principles or strat igraphic clas­ sification and terminology).narta, 25/5. 233-236, zagreb. herak, m . (1975): some com men ts on strati graphic classification ancl terminology (ncke primjedbc li z stratigrafsku intcrpretacij u i tcnninologiju).gco­ loski vjcsnik, 28, 55-63. herak, m. ( 1976): cilj, namjcna i sadrzaj gcoloske karte sfrj 1:50.000.geoloski vjcs nik, 29, 363374. herak, m. (1 984) : geol ogija. postanak, tektoni ka i cli namika zem ljc. razvoj ni put zcm lje i zivoth. gco­ loska grada kont incnata i oceana. 3rd ed. , skolska knj iga, zagreb, xx+429 p. herak, m. (i 987a): geolog ija. postanak, tektoni ka i dillal1l ika zcmlje. razvoj ni put zcm lje i zivola. gco­ loska grada kontinenata i occana.4 th ee\. , sko lska knj iga, z agreb, xv+433 p. herak, m. (1987 b): t rijas oinarida na pre law izme­ du herci nske i alpinskc orogenczc (the t ri assic of the dinaridcs, the linking peri od of hercynian and a lpinc orogenesis).zbornik radova posveccn aka­ dcmiku z . bcs icu, c rnogorska akademija nauka i umjelnost i, 33-38, t itograd . i .'" herak, m . (1 990): geologija. poslanak, lcktonika i dinamika zei11lje. razvojni put zemlje i zivota. geo­ loska gfada kontinenata i oceana. 5th cd. , skolska knjiga, zagreb, xv+433 p. herak, m. & bah un , s. ( 1963): pril og slraligra­ fskoj anali zi nas laga u podrucju slunj-komesarae­ rakoviea, j-irvatska (ein beitrag zur strati graphis ­ chen anal yse der ablagerun gcn im gebie t slunj­ komesarac-rakovica, kroatien).geoloski vjesnik, 16 ( 1962), 33-34. herak, m. & bojanic, l. (1966): rcvi zija lrijasa u poclrucju rijekc koranc izmeclu barilovi ca i slunja (rcv ision dcr tri asabjagerungen im gebie t des flusses karana zwi sche n barilovic und slu nj).­ gcoloski vjesnik, 19( 1965), 47-51. herak , m. , majcen, z. & korollja, 13. (1965): pr il og paleontol o.skoj dokumenlac iji illezozoika u samoborskolll golju i si zumberku (beitrag zur palaonlologischen dokulllentation des mezozoi­ kui11s illl samoborer gebirge und dem ne zumbe­ rak). geoloski vjesnik, 18/2 ( 1964), 325-332. herak , m. sokac, b. & sca vnicar, b. ( 1967) : correlation of the triass ic in sw lika, paklen ica and gorski kolar (croalia).geologicky sbornfk geo logica carpathica, xvili/2, 189-202, bralislava. herak , m. , scavnicar, b., susnjara, a. , durdanovic, z. , krysty n, l. & gruber , b. ( 1983) : the lower triassic of mue. proposal fo r a standard section or the european upper scythian. ­ in: neue beilrage zur b iostratigraphic de l' tcthys­ trias. osterreichi sche akademie clef wi ssen­ schal"len , sehriftenrcihe der e rdwissensc haftli chen kommissionen, 5, 93-106, wien. tajder , m. & herak, m. ( 195 1): pclrografija i geo­ logija.skolska knjiga, zagreb, vlii+23 i p. tajder , m. & herak, m. ( 1959): pclrografij a i gco­ logija. 2nd ed. , skolska knj iga, zagreb, x+280 p. tajder , m. & herak , m. (1966): pelrogral"ija i geo­ logija. 3rd cd., skolska knji ga, zagreb, x+400 p. doprinos prof. heraka stratigrafiji trijasa "u dinaridima irijas je veoma dobro razvijen , pa predstavlja veoma vai an clan sredozeml1og trijasa." (herak, 1984, p. 205) prvih d vadcsctak godina znanstvenog facia profe­ sora hc raka lllozemo slobodllo nazvati trijaskim peri­ odom. asocirajuci na irodjelnu podjelu irijasa taj bismo period ii jeclnoj ne rormalnoj kronoloskoj podjeli mogli nazvati "rani herak" . "srednj i herak" bi obuhvat io "krski period", dok bi "kasni herak" bio obiljezen geo­ icktonikolll dinarida. sv oje zanim3njc za nasi age trij asa herak l1loguce du gujc geoloskom kartirallju u ekip i pro fesora salope­ ka , a vjerojatno i kasnijc ll1 radu na svoj oj dizertaciji kod juliusa von piae u beeu (herak, 1943, 1944). u svojim ist razivanj imcl cesto obraduje svoj rodni zu m­ beracki kraj , pa jc i prvi njegov stratigrafski fad onaj 0 strati grafskom rasc lanji vanju l11 ezozojskih nasjaga j ugozapadllog d ije la zumberackc gore (1-1 erak, 1947). u toill radu 011 ukratko navodi rezuhale dviju gco loskih ckskurzija u to podrucje. 0 islrazi vanj ima u susjcdnom sa ll1oborskoll1 gorju izvj eslava herak ( 1954a, b, 1955), a zat im izlazi i njegov znacajni rad: "geologija sall1oborskog goi]a" (herak, 1956a) , u koje ll1 dela­ ijna opisuje stratigrafskc jed inice i tektonsku gradu tog podrucja. osobitu paznju po klanja nas iagam 3 iri jasa. herakova istrazivanja pokazala su znalno vecu raspro­ slranj cnost nas laga donj eg trijasa nego sto sc ranij e mi slil o, a za gips, ranijc pripisivan donjcm trijasu, si11(\­ tra da je pajeozojski. u srednjem i gornjcm trijasu raz­ likuje dolom ite, ladinicku mjciiovitu skriljavo-iaporovi­ to-vapnenacku serij u s tufov ima i roznjacim a, ie vc li ­ kolrnske nasjage koje uvrstava u gornji lrijas, uz suiti ­ nju da se radi 0 ladiniku. herak et al. (1965) na temc­ iju makrofaune utvrduju gornjotrij asku starost dijc ja karbonatnih sukces ija l1a podrucju zumbcrka, te doka­ zllju gornjokrednu starost velikotrnskih nasiaga. poslje­ dnj i radovi u kojima navodi nove nalaze trijasa datiraju iz sezdesclih (herak, i 966b, 1968), ali svoju vczu sa stratigrafijom trijasa zumberka nastavlja i u najnovije vrijeme kao recenzent l1a projckw geoioske kan e republike hrvatskc 1:50.000. tstrazivanja trijaskih nas laga herak provodi u okvirll reg ionalnih geo]oskih istrazivanja na podrucju korduna i like. tako herak (i9540, i 956c) u podru­ cju rijcke korane utvrduje znalno rasprostranjcnje tri koch 8.:. (jrga~(l\lic: professor 1 krak's contribut ion 10 triassic stral igraphy jaskih nas laga, posebno dololllita, na kojillla kontinui ­ rano s lijede dolomiti lijasa, a kasnije herak & bahun (1963) i herak & bojanic (1966) deta­ ljnije islrazlijll trijaskc nasi age i dokazuju donji i gornji trijas. u svoj im radovim<-t ilerak korisli "algll" sphae­ i'ocodilllll bomclllonni kao dokaz gornjeg trijasa (l-ter­ ak, 1952a, b, 1956a, 1957, 1962, 1963, 1966b, 1968; iierak & llaiiun, 1963; herak & boianic, 1960). rako se pokazalo cia se ne radi 0 algi vee 0 sedi­ mcnloloskoj s irukiuri onkoidu (ilallic, 1970) kara­ kle ri s licni slojevi s krupnim onkoidima i dan as sluze kao inclikacija gornjotrijaskih naslaga, gclje se eesto pojavljllju u vecem broju. herak (1950) vee ukazllje na vclik znacaj clazi­ kladalllih alga ii stratigrafskoj razdiobi trijaskih sukce­ s ija, cime je povezao dva svoja inleresna podrucja. kontinuirano prollcavajuci taksonomske odnose i st rati ­ gra fsku c1islribllc iju ovih alga, herak ih koristi u rjdavanjll problelllatike stratigrafije trijasa u brojnim gcoloskilll radovillla. u podrucju gracaea, herak ( 19.56b) na temelju dazikladalne norc odvaja anizicke od lacliniekih naslaga, te clokazllje diskordaneiju izmedll lad ini ka i karnika. na istom lerenu herak ( 1960c) ulvrduj e diskordantan odnos izmeclu perma i trijasa, clokazujc srcdnji trijas pojllocu alga provodnih za anizik i ladinik i upotpunjava intcrpretaciju diskordancije izjllcdll sred nj eg i gornjeg trijasa. obradujuci nasi age trijasa ii okolici sv. roka u lici herak (1965) jos jcdanpul potvrcluje vrijednosl daziklaclalnih alga u raz­ cliobi sreclnjeg trijasa na katove, te reviclira neke do tada poznale raspone pojeclinih vrsta. profesor he rak je saznanja svoja i ostalih geologa sintctizirao i rcdov ito prezcntirao domacoj i svjctskoj gcoloskoj javnosli popularizirajuei tako nasu geologiju 1i svijctu. stratigrariju lrijasa hrvatske, koja se temelji na daziklaclalnilll algallla, akaclemik herak je po prvi put a prezentirao svje tskoj geoloskoj javnosti na medll~ narodnom geoloskolll kongrcsu ii copenhagenu (her­ a k, 1960b). na meclunarodnol11 kolokviju 0 trijasll 1i monlpcllicru 196 1 (herak, 1962, 1963) prikazani sli glavn i bioslratigrafski, liloloski i palcogeografski odno­ saj i irijasa 1i llrvatskoj , te naglasena llloga pojeclinih orogenclsk ih fanl za fonniranje lrijaskih naslaga i nji ­ hovu rasp rostranjcnosl. na prec\avanju odrzanom u geoloskom druslvu 1i bceu herak ([ 966) naglasava 155 ulogu vapnenackih alga u strat igrafiji dinarida. na mcdunarodnom kolokviju 0 stratigrafiji trijasa ii s10vackoj , herak ct al. (1967) su dali korclaciju irijasa like, pakleniee i gorskog kotara uz prikaz f'osilnc zajednicc s iczislem na claziklada1ne algc. herak ([973b) daje prikaz novijih istrazivanja trijasa u hrvat­ skoj , a herak (l987b) preglecl trijasa dinaricla u svjc­ till pr ijclaza izlllcdll herc inske i alpskc orogcncze. na illedllnarodnolll silllpozijll u heeu 0 stratigrafiji alpsko-mcditeranskog ir ijasa, herak (1974a) jc sazeo rezultatc svog rada na istrazivanju problelllatike lrijas­ kih naslaga dinaricla s naglaskom na palcogcografiju i faeijese. l-1erak.ie vee tada ukazao na problclllatiku koja je jos i danas aktualna: " pal eogeografski uvjeli fae i­ jesnog razvoja trijasa relativno uskog prostora hrvatskih dinarida odrazavajll dinamiku bez jasnog vrel11enskog i faeijesnog preklapanja granicnih s lojeva razjici tih kato­ va i scrija. stoga je primjena kronostr<lligrafskih jedini­ ea u s trati grafskoj klasifikaciji otczana i visc-manjc umjctna. zato prcdnost imaju neformalnc li los traligrac­ ske jcdiniee kojc bolje oslikavaju prirodne oclnosaje. u lim sc slucajevima kronostratigrafskc granice irclirajll opccnito i visc-manjc dinamicno. svaki pokusaj takvll dinamicnost utisnuti ii konstruirani statican okvir, precl­ slavljalo bi maskiranjc prirodnih odnosaja. " jedan od nesllmnjivo znacajnih doprinosa slrali­ grafiji trijasa predstavlja prijedlog 0 stnttotipll za europ­ ski gornji skit ii podrucjll muea (herak e l ai., [983), iznesen na simpoziju 0 biostratigrafiji trijasa '('eti sa, 0 ccmu svjecloci opcenito vcliki inlcrcs slldionika 0 10m prijcdlogu. uz stralig rafiju ga veze i njcgova nas lavna aklivnosl kao profcsora stratigrafske i regionalne geo[og ij e . 0 lome pise i u svojilll ud7.benicima (herak, [960a , 1973a, 1984, 1987a, 1990; tajder & herak, 1951 , 1959, 1966). herak disklltira i 0 generalnoj stratigrar­ skoj problcmalici (iierak, 1 974b, 1975 , 1976), ie je aktivan, kao jcdan od g[avnih savjctnika, i ll priprcmi izrade nove gco[oske karte republike i-jrvatskc 1 :50.000. zakljucimo na kraju kako je doprinos koji je profe­ sor iierak ciao ii stratigrafiji trijasa izniman , pri cemu treba posebno istaknuti primjcnll claziklaclalnih alga ii stra tigrafiji i sin tczli spoznaja 0 racijcsnom i paleo­ gcografskom razvoju trijasa u hrvatskoj. \jcoioghl i...-roanca :ju/l ab stra ct the genus mariopteris zeiller is distributed from the namurian a to the early stephanian in europe. in the ­dobrudzha­basin,­numerous­specimens­are­found­mainly­in­flood­plain­claystones­and­siltstones.­the­habitat­and­ reconstruction­of­the­plants­suggests­a­creeping­manner­of­growth.­climatic­changes­are­reflected­in­the­architecture­ of­species.­one­specimen­has­an­attached­seed­proving­the­classification­of­the­genus­as­a­pteridosperm. keywords: mariopteris, pteridosperm, creeping plant, attached seed 1. introduction the genus mariopteris has attracted the attention of many palaeobotanists. zeiller (1878, 1879) created this genus that is now known to embrace species that were referred to different genera. many monographs (huth, corsin, danze-corsin, boersma), and part-authors of large monographs (zeiller, stur, gothan, kidston dates needed here too), and other articles concern these plants.­while­the­architecture,­classification,­taxonomy,­synonymy and species diversity are frequently discussed, the habitat of this group is rather poorly considered. it is accepted that they are probably creeping, intertwining or climbing, in habit. 2. plant elements and terminology boersma (1972, p. 24) used the term “frond” for the “... spirally arranged leaf-like structures”… delavoryas (1962, p.120) commented that “...at medullosa...leaves in their­basal­region­resemble­stems­with­many­steles.­externally, it would be impossible to distinguish between leaf and branch.­here­the­terms­stem,­leaf­and­stalk­are­usеd. 2.1. roots there is no published information on them, but it is possible that the stem, which is partly covered by wet sediments, also possesses the function of a root. the trichomes on the stem at­the­apex­of­the­plant­(corsin,­1932,­fig.­29)­might­be­ root appendices. 2.2. the stem it is straight or slightly sinuous and covered by longitudinal striations and regular short transverse bars. a group of plants, regarded­by­danze-corsin­(1953)­as­alinae, do not have transverse­bars­and­boersma­(1972)­excludes­them­from­ mariopteris. there are few illustrations of stems. the stem is slightly elliptical with the leaf stalks, or their marks, situated at equal distances on the stem. one pair of leaves is located on the lower­external­part­and­another­pair­is­approximately­half­ the­distance­to­the­top­stur­(1885,­pl.­22,­fig.­1).­stur­ (1885,­p.­285,­pl.­22,­fig.­1)­regards­this­arrangement­as­a­ spiral­of­four­bases­in­one­cycle.­danze-corsin­(1953,­ figs.­7–9)­supposed­there­to­be­a­helix­built­of­five­leaves.­ zeiller (1888) regards the arrangement of the leaves as two generatrice situated at an angle less than 180°. the longitudinal­striation­of­the­stem,­illustrated­in­many­figures,­is­ straight and does not indicate any spiral growth. the position of each of the four consecutive leaves is repeated along the stem, and can be regarded as helical that is not the result of­axial­rotation.­therefore,­the­fourfold­alternation­characterizes­the­leaf­arrangement­–­fig.1. geologia croaticageologia croatica geologia croatica 65/3 361–366 4 figs. 2 tabs. zagreb 2012 structure, habitat and seed of mariopteris zeiller  yanaki georgiev tenchov geological­institute­of­the­bulgarian­academy­of­sciences,­g.­bonchev­street­block­24,­1113­sofia,­ bulgaria; (ytenchov@abv.bg) doi: 104154/gc.2012.25 geologia croatica 65/3geologia croatica 362 there is neither information nor data for the total length of the stem, although the length of one cycle of leaves in a well-developed­stem­is­280­mm­(stur,­1885,­pl.­22,­fig.1).­ the­known­maximum­width­for­a­stem­is­22­mm­with­a­ gradual reduction in each cycle of about 1 mm. if this reduction­in­width­was­even,­the­length­would­be­about­21­x­280­ mm = 6.0 m or more. 2.3. stalks and leaves the leaves are pinnate with a massive, longitudinally striate naked stalk (petiole) up to 150 mm long and 7 mm wide at its base.­the­stalk­axes­are­directed­upwards­at­a­40°­angle­to­the­ stem­axis­(danze-corsin­1953,­figs.7–9).­the­stalk­bifurcates­for­the­first­time­at­an­open­angle­in­two­parts­(rachises­ in many authors), which in their turn bifurcate up to 5 times. after the third bifurcation they are covered by pinnae (lamina). the leaf blade is parallel to the stem and to the ground. its­axis­is­either­parallel­to,­or­at­some­angle,­to­the­stem­axis.­ the pinnae in the blade are in one plane that is parallel to the stem­axis­and­the­ground.­the­pinnules­length,­width­and­neuropteroid or pecopteroid base depends on the species. boers ma (1972, tables vii to xiv) gives data for the size of the leaf elements for 7 species. table 1 summarizes some of the data. pinnules near the top of the plant can have spinelike lobes or are totally formed as spines. in the mariopterids, two architectural types of leaf blades are known and designated as bipartite and quadripartite. danze-corsin­(1953,­p.­57–58,­p.­256)­indicated­that­ the fronds of mariopteris have in its base and along its length quadripartite leaves but are bipartite in its sub-terminal part. the transformation to bipartite in quadripartite leaves is documented­by­danze-corsin­(1953­pl.­40,­fig.1;­pl­10,­fig.­ 1,­respectively­pl.­11,­fig.2).­this­can­be­regarded­as­acceleration during the growth in the leaf architecture of a species. she (idem p. 58, plate 56) supposed that simple pinna were situated at the terminal part of the stem, but this is not evident­in­the­figures.­boersma­(1972)­does­not­mention­ anything about simple pinna, although he accepts that the genus mariopteris­consists­of­two­groups­of­species­–­one­ that has bipartite leaves and another that has quadripartite leaves.­the­bipartite­leaf­possesses­exterior­pinna­that­gradually diminish in length. the quadripartite leaf possesses a long pinna at the base of the tertiary rachis, followed by a pinna­of­calceolate­form.­for­this­reason­he­divides­the­mariopterids into two genera: karinopteris boersma for bipartite fronds and mariopteris (zeiller, boersma emend.) for quadripartite fronds. boersma (1972) does not comment on the opinion of danze-corsin that bipartite leaves are situated at the top of plants with quadripartite leaves. however, he indicated as “aberrant forms” those specimens of mariopteris (zeiller, boersma emend.) that have bipartite leaves. m. nervosa kidston (1925, pl. figure 1: interpretations of leaf position. table 1: maximum known size of leaves of mariopteris zeiller species length mm width mm data from: m. acuta >500 > 240 boersma fig. 76 danze-corsin p. 83 m. beneckeii 750–800 >260 huth fig 5 danze-corsin p. 104 m. bourosii ? ? only p4, p5 known m. carnosa >140 > 320 corsin pl. 68 m. daviesii ? ? only p3 known m. dernoncourtii 600 250 danze-corsin p. 94 m. grandepinaa >230 >260 huth fig. 1 m. hirsuta ? ? m. hirta 350 > 200 danze-corsin p. 149 m. lobatifolia >259 160 danze-corsin pl. 63, fig. 2 m. microsauveurii >180 >150 danze-corsin pl. 59, fig. 1 m. muricata >370 > 180 huth fig 2 stur 1877 m. nervosa >180 >360 boersma text fig. 7 m. odontophylla 160–180 > 120 danze-corsin p. 137 m. opulenta 750 >440 pl. 68 fig.1 danze-corsin p. 175 m. pachyphylla 450–600 >200 pl.61, fig.1 danze-corsin p. 202 m. robusta ? ? m. sauveurii >180 >160 danze-corsin figs. m. soubeirianii >400 300 danze-corsin p. 213 yanaki georgiev tenchov: structure, habitat and seed of mariopteris zeiller geologia croatica 363 144,­fig.­4,­4a);­boersma­specimens­of­m. sauveurii (his pl.­5,­fig.10)­and­of­m. muricata (his­pl.­21,­fig.­55)­should­ all be regarded as “minute fronds of mariopteris”. this suggests­that­the­proposed­taxonomy­should­be­re-examined. both­type­of­leaves­are­asymmetric,­as­is­well­expressed­ by­the­width­of­their­internal­and­external­parts.­the­asymmetry was the subject of attention by danze-corsin (1953)­in­almost­all­species­described­by­her. the leaves are large and require strong stalks to support them. the length of the leaves is longer than the length of the distance between the leaf stalks. the plane of the leaf blade most probably is parallel to the ground. in adult plants the­lower­pair­of­pinnules­is­about­7­cm­while­the­next­is­ about 9 cm above the ground. 2.4. aphlebia danze-corsin­(1953,­fig.7,­p.­45)­accepts­as­aphlebia some­small­excrescences­at­the­base­of­the­leaves.­it­is­not­ supported here. 2.5. pinna, pinnules and venation the pinnae are lanceolate and slightly or more asymmetric elements formed on stalk branches. the width and the length (which­can­be­more­than­300­mm),­depend­on­the­species­ and on the position on the leaf. the pinnules are the smallest part of the leaf blade and their morphology depends on the species as detailed by boersma (1972). they are attached by pecopteroid or sphenopteroid bases. the basal basiscopic and acroscopic pinnules in a pinna of ultimate order, have strongly developed outgrowths of their basal basiscopic lobes. in some cases, the terminal pinnules of a pinna, and part or all of the pinnules in lower situated pinna, are formed in spines, as­figured­by­huth­(1912,­viii,­143,­fig.­1).­the­ pinnules have a midvein that arises obliquely from the stalk, curves and reaches at least halfway up the pinnules and secondary vein branches that emerge alternately from the midvein­and­dichotomise­one­or­more­times,­ending­at­the­apex­ of the pinnules. cuticle analysis by barthel (1962) and kerp and barthel­(1993­–­but­not­pl.­5,­fig.­1–4!)­established­that­ stomata are closely spaced on the lower surface of the pinnules but absent from the upper surface.. 2.6. bud (“bulbil”) huth (1912) used the term bulbil for round buds, up to 1.5 mm across, occurring on the stems of some species of mariopteris.­corsin­(1932)­regarded­them­as­an­early­stage­of­ unopened­pinna.­some­of­them­occur­in­the­axils­of­normal­ leaves­(huth­–­fig­5)­and­others­on­the­inter-leaf­space­of­ the­stem­(huth­fig.­3;­corsin­1932­pl.­76,­fig­1).­it­seems­ that they never occur on fully-formed leaves. the leaf grew by linear development (envelopment, opening) from a spiral. some phases of this are illustrated by­corsin­(1932,­fig,­29­and­plate­76,­figs­1–5),­huth­ (1912,­viii,­141­fig.­2),­corsin­(1932­text-fig­29,)­and­ gothan­(1935­pl.­29,­fig.­4).they­are­summarized­here­in­ figure­2.­at­an­early­phase­the­spiral­looks­like­a­bud.­the­ leaf­spirals­are­parallel­(twin­spiral)­and­visible­in­fig.­4­of­ huth. after some growth, the two parts separate and turn to­left­and­right­as­in­an­open­leaf.­а­phase­of­this­is­illustrated­by­corsin­(1932­at­fig.29­and­plate­76). figure 2: phases of leaf development. 1/a– a bud in the base of stalk (huth, 1912, 141, fig. 5); 2/b– bud in the middle of a stalk(huth 141, fig. 3); 3/c– bud developed in a twin spiral (huth 141, fig. 4); 4/d– the top of the stem with numerous unopened leaves (corsin 1932 fig.29); 5/e– leaf in the opening of the spiral (huth 141, fig. 2). geologia croatica 65/3geologia croatica 364 2.7. the spines the spine-like form of the pinnules seems to be provoked by­heliotaxes,­when­a­young­specimen­is­in­full­shadow­bellow adult plants. in such cases, the leaves of its top part are directed upwards towards the light. they are covered by spine-like pinnules as documented in huth (1912, viii 143,­fig.1).­the­spines­help­the­enveloped­leaves­behind­the­ plant top to intertwine through the leaves of the adult species, (that shade out the light), and then to continue development over the other leaf. this is shown by m. carnosa (corsin,­1932,­pl.­68).­the­older­specimen­has­larger­pinnules­ and­no­spines­(left­part­of­the­figure).­the­younger­specimen­ (visible along x-y line), has smaller pinnules and numerous spines that are at y – the top of the specimen. when the plant reaches the sunny surface, the spine-like pinnules start to transform­themselves­from­their­base­towards­the­apex­as­ normal pinnules. different phases of this transformation are illustrated­in­numerous­figures­of­corsin­(1932­–­pl.63,­ fig.­2,­pl.72,­figs.­2,­4),­danze-corsin­(1953)­and­in­that­ of huth (1912). therefore, mariopteris under some conditions can be intertwining with plants at an early phase of growth. 3. reproduction until now, it has generally been accepted that the mariopterids are pteridosperms, but there is a lack of evidence of their method­of­reproduction.­gothan­(1935,­p.8–14)­supposed­ that vegetative reproduction was possible by means of buds. boersma (1969) established that mariopteris latifolia (brongniart) zeiller is really a fern, and referred it to a new genus fortopteris boersma, as fortopteris latifolia (brongniart) boersma. it has quadripartite constructed leaves. this species (and genus) differs from the mariopterids by some denticulation of its pinnules, and by its stem having no transverse bars. the missing transverse bars on the stem stimulated danze-corsin to create a “group alineae” in the mariopterids. the possibility that mariopteris is a seed fern is based on an analogy with dicksonites pluckenetyii which has small seeds situated on the lower surface of its pinna. in mariopteris the majority of fossils show the upper surface. this suggested­re-examination­of­slabs­with­mariopteris in the dobrudzha collection. a seed-bearing mariopteris beneckeii (sample­n­16344)­was­found­on­a­sample­from­borehole­ number 218 at 1406 m depth, corresponding to a level about 218­m­above­the­base­of­the­mogilishte­formation­in­the­ middle­part­of­the­langsettian.­the­specimen­shown­on­fig. 3­is­from­a­young­leaf­in­which­a­part­is­reversed,­exposing­ its lower surface possessing at least one small seed. this suggests that mariopteris as many other ancient plants e.g. some lepidodendrons, after some time in a vegetative phase entered a reproductive phase that then led to the death of the plant. two advantages of this strategy are that the seed is dispersed far from the mother plant root (6 m. or more) and may be out of the mariopteris carpet thereby enlarging its range, and secondly in opening up places in the habitat for a new generation of plants. in the one metre interval at 1406 m depth in borehole 218, there are seven samples of mariopteris and another two with eusphenopteris. individual pieces of shale are about 1 cm­thick­and­the­unexposed­parts­of­them­also­contain­plant­ remains. the plants were preserved with their upper surface upwards,­either­by­being­flattened­by­an­inrush­of­turbid­ flood­water,­or­death­after­a­reproduction­phase.­leaves­reversed with their lower surface upwards are rarely found and illustrated. this seems to indicate that mariopterids lived in places with a low water dynamic. 4. mariopteris construction parts of the published accounts of several species are used for the construction of the mariopteris plant. those stems possessing the marks of leaf bases show them to be equally spaced with the distances between them being no more than 170­mm.­the­leaves­are­flat­and­directed­at­angle­to­the­stem­ direction. the construction of the fronds is regarded as phases in architecture building with the steps as: appearance –­acceleration­–­retardation­–­disappearance­–­figure­4. 5. habitat the habitat of the mariopterids has been rather poorly discussed­in­the­past,­although­the­opinion­by­gothan­(1913­ p.88) that mariopteris­lived­on­the­forest­floor­as­a­creeping,­ climbing and intertwining plant is generally accepted. unfortunately, there is no real evidence to support this view. kerp­&­barthel­(1993­plate­5,­figures­1–4)­accept­that­ the documented hooks are of a climbing karinopteris, but the plant seams to be eusphenopteris so, a climbing habit of mariopteris is not supported by the facts. in­the­dobrudzha­coalfield,­mariopteris specimens occur in all coal bearing lithostratigraphic units. they are rare in­the­rakovski­formation­(namurian­a),­frequent­in­the­ mogilishte,­makedonka­and­krupen­formations­(namurian­ figure 3. the seed-bearing specimen 16344 dobrudzha coalfield borehole 214, 1508 m in the mogilishte formation in the mid part of the langsettian. i think this image would benefit from annotation eg an arrow pointing to the seed? yanaki georgiev tenchov: structure, habitat and seed of mariopteris zeiller geologia croatica 365 c­–westphalian­d),­and­rare­upwards­ to­ the­stephanian­ (gurkovo­formation).­they­are­also­rare­in­the­fluvial­sediments where allochthonous fragments are rarely observed. as autochthonous specimens they are frequent in the sediments overlying the coal seams, especially in the upper part of­the­mogilishte­formation. in­the­flood­plains,­the­mariopterids­formed­a­thick­carpet of creeping and intertwining mariopteris plants. here and there, some bush-like plants of sphenophyllum and some seed ferns such as neuralethopteris, alethopteris, lonchopteris and eusphenopteris – table 2 occurred. paripterids are allochthonous. the detached seeds are autochthonous and did not germinate in the full shadow and cold milieu bellow the mariopteris carpet. during­flooding,­the­creeping­plants­were­submerged­in­ muddy­water­and­fine­sediment­may­have­been­deposited­on­ them..­this­could­explain­why­mariopteris has no stomata on­the­upper­surface,­as­they­would­have­been­filled­by­the­ fine­sediment.­the­stalk­was­massive­enough­to­support­the­ large­leaf­and­the­fine­sediment­covering­it­after­the­retreat­ of­the­flood­water.­sediment­could­be­washed­away­by­rainfall, but if it dried the plant might die. in cases when the floods­covered­the­plain­to­significant­depth,­the­amount­of­ the­fine­sedimentary­deposit­could­be­so­thick­and­heavy,­ that the mariopteris plants were crushed below it. this is the most probable reason why the leaves are mainly preserved with their smooth upper surface uppermost. the reproduction problem could also be bound up with floods.­the­area­of­a­flood­plain­that­is­covered­by­deep­water looses all its mariopteris carpet, but the carpet seems to be­restored­very­rapidly,­post­flooding.­ferns,­of­course,­can­ quickly­re-establish­from­dispersed­spores.­for­mariopteris there are two possibilities that are at present hypothetical. the plants may quickly spread from areas beyond the reach of­the­flood­waters­or­be­re-established­by­seeds. 6. stratigraphic distribution in europe the genus is known from the namurian a to the cantabrian and the stratigraphic distribution in europe is considered by huth (1912). m. acuta, m. beneckeii, m. muricata and m. carnosa are found in the donets basin (novik, 1952) and the north caucasus (anisimova, 1979: novik, 1978). the species diversity in the dobrudzha coalfield­is­comparable­with­that­of­other­basins­around­the­variscan ranges in europe. 7. conclusion mariopteris plants formed a cover in the coastal and alluvial plains and around the swamps. this, combined with their creeping­growth­form,­explains­why­they­are­so­widely­distable 2: mariopteris and associated plants in flood plain of the svoge and dobrudzha coalfields svoge coalfield dobrudzha coalfield mariopteris associated mariopteris associated westphalian d-cantabrian absent robusta, sarana sphenophyllum, alethopteris, callipteridium westphalian c absent sarana sphenophyllum, alethopteris westphalian b nervosa sphenophyllum muricata, nervosa, sphenophyllum, alethopteris, lonchopteris westphalian a acuta, muricata sphenophyllum, neuralethopteris muricata, nervosa, sphenophyllum, alethopteris, lonchopteris, neuralethopteris namurian c acuta, muricata sphenophyllum, neuralethopteris acuta, muricata, beneckeii sphenophyllum, alethopteris, lonchopteris, neuralethopteris namurian a absent acuta sphenophyllum, alethopteris, neuralethopteris figure 4. phases in architecture building. geologia croatica 65/3geologia croatica 366 tributed in the variscan foreland of europe. their creeping habit helped them to cover the plains and to migrate along river­beds­and­ the­flood­ terraces.­even­ if­ they­advanced­ yearly­by­only­1­metre,­in­the­2–3­million­years­(life­span­ of m. acute and of m. medicate)­they­could­migrate­2–3.000­ kilometres along river banks, the coastal margin of the sea, the outer fringes of large lakes and through the swamps from the british isles to the turkish black sea coast and the caucasus. the climatic changes towards drier conditions and longer periods without rainfall would have reduced their habitat until they disappeared around the beginning of the stephanian. acknowledgement this paper was presented at the zagreb meeting 2011 and is a contribution to igcp project 575 “pennsylvanian terrestrial habitats and biotas of southeastern euramerica”. i am grateful to the reviewers for their remarks and help with language editing. references anisimova,­o.i.­(1979):­flora­i­fitostratigrafia­srednego­karbona­severnogo. kavkasa, naukova dumka. kiev (in russian). 47 pls., 107 p. barthel, m. (1962): epidermisuntersuchungen in einigen inkohlten pteridospermenblattern­des­oberkarbons­und­perms.–­geologie,­ beih,­33,­1–140. boersma, m. (1969): a fertil leaf of “mariopteris latifolia”. meded. rijks­geol.­dienst,­n.­ser,­20,­65–77. boersma, m. (1972): the heterogeneity of the form genus mariopteris zeiller,­atlas­43­plates,­172­p. corsin,­p.­(1932):­mariopteridees.­et.­git.­miner.­france­bassin­houiller­ de­la­sarre­et­de­la­lorraine.­i.­flore­fossike­3me­fasc,­111–173. danze-corsin,­p.­(1953):­contribution­a­l’etude­des­mariopteridees.­ les mariopteris du­nord­de­la­france.­etud.­geol.­atlas­topogr. souterr serv. geol. h.b.n.p.c., 1/1, atlas, 78 plates, 269 p. delavoryas,­t.­(1962):­morphology­and­evolution­of­fossil­plants.­ holt,­rinehart­&­winston,­n.y.­chicago,­san­francisco,­toronto,­ london, 189 p. huth, w. (1912): mariopteris.–­in:­h.­potonie­(ed):­abbildungen­ und­beschreibungenfossiler­pflanzen-reste.–­koenigl.­preuss.­ geol. landes-anstalt, 8,­140–160. gothan,­w.­(1913):­die­oberschlesische­steinkohlenflora.­i­farne­und­ faranliche gewachse. abhhandl.konigl. preuss. landesanstalt. n. folge,­278­p. gothan,­w.­(1935):­dir­steinkohlen­flora­der­westlichen­paralischen­ steinkohlenreviere­deutschlamds.­lief.­3.–­abh.­preus.­geol.­landesanstalt;­pls.­32–47,­82­p. kerp.­h.­&­barthel­m.­(1993):­problems­of­cuticular­analysis­of­ pteridosperms.–­rev.­palaeobotany­and­palynology,­78,­1–18. kidston,­r.­(1925):­fossil­plants­of­the­garboniferous­rocks­of­great­ britain.–­mem.­geol.­surv.­gt.­brit.,­palaeontol.,­2/6. novik,­e.o.­(1952):­kamenougolnaya­flora­evropeiskoi­chasti­sssr.­ (in­russian)­–­ac.­sc.­sssr,­468­p. novik,­e.o.­(1978):­flora­i­fitostrafigrafia­vehnego­karbona­severnogo­kavkasa­(in­russian)­kiev,­naukova­dumka,­31­pls.,­164­p. stur,­d.­(1885):­die­carbonflora­der­schatzlarer­schichten.­abt.­i:­die­ farne­der­carbonflora­der­schatzlarer­schichten.–­beitr.­kennt.­ flora­vorvelt,­keiser.­koenigl.­geol.­reichsanstalt,­11/1,­418­p. zeiller,­r.­(1878):­vegetaux­fossiles­du­terrain­houiller­de­la­france.­ atlas. zeiller,­r.­(1879):­vegetaux­fossiles­du­terrain­houiller­de­la­france.­ –­explic.­carte­geol.­france,­4/2,­185­p. zeiller,­r.­(1888):­vegetaux­fossiles­du­bassin­houiller­de­valensiennes.–­etude­des­gites­minereauxde­la­france,­731­p. manuscript received january 11, 2012 revised manuscript accepted october 17, 2012 available online october 30, 2012 gc_2-2013_kb.indd  geologia croatica 66/2 151 zagreb 2013 geologia croaticageologia croatica comment on the paper "defi nition of the river gacka springs subcatchment areas on the basis of hydrogeological parameters" by lukač reberski et al., published in geologica croatica 66/1, 39–53 (2013)  zvjezdana roller-lutz1, tamara hunjak1 and hans o. lutz1,2 1 medical faculty, rijeka university, braće branchetta 20, 51000 rijeka, croatia; (roller@medri.uniri.hr) 2 faculty of physics, bielefeld university, bielefeld, germany doi: 10.4154/gc.2013.12 this paper by lukač reberski et al. (in the following referred to as paper i) presents measurements of hydrological and hydrochemical parameters as well as results of an isotopic analysis of the spring waters and the precipitation. as the authors of paper i mention, the isotopic analysis has been performed in graz and in rijeka. we want to point out that the data for the year 2008 resulted from a cooperation project which was headed by rijeka university and supported by the international atomic energy agency (iaea vienna); the corresponding isotope results were preliminary and shown only in an unpublished and not citable report. in spite of a confi dentiality agreement, the authors of paper i took these data without our consent. this breach of trust and the somewhat sloppy data handling has some unfortunate consequences: the isotope data shown in fig.7 appear to scatter between the local and the global meteoric water lines, lmwl and gmwl. this was used to argue a direct correspondence between precipitation and spring recharge. firstly, note that this lmwl is plotted incorrectly in fig. 7; the correct lmwl (eq.5 in paper i) had to be lower by about −1‰ (i.e. shifted to more negative δ2h values) if compared to the plotted line. therefore, the majority of data points are actually located slightly above the correct lmwl. the fi nal analysis of the 2008 isotopic data further corroborates this small but noticeable effect; as a consequence, the d-excess d = δ2h − 8۰δ18o is somewhat higher for the spring waters than that of the precipitation, supporting the conclusion that recharge happens mainly during the cold season (c.f. also mandić et al. (2008)). furthermore, the absolute altitude values of the recharge areas (c.f. the end of section 7.3 in paper i) cannot simply be inferred from the measured isotopic ratios; the available data can only provide (approximate) values for the altitude differences. the reason is that the derivation of absolute values requires some reference data, e.g. the long-term mean δ18o of the precipitation at the spring altitude (more precisely, taking into account the mean residence time of the ground water as well as the infi ltration into the catchment); or a reliable value of the absolute altitude of at least one of the recharge areas (assuming that the soil surface and thus the infiltration is of approximately the same nature for all catchments). without further discussion neither is really known; for example, depending on the season, the δ18o values of the collected and analyzed rainfall in the gacka spring region in the years 2006 and 2008 vary between approximately −4‰ and −13‰. the authors do not provide any clue for the reference data they used. the publication of the fi nal analysis of our results, together with an estimate of the mean residence time of the ground water as obtained from tritium model calculation, is presently under preparation. references mandić, m., bojić, d., roller-lutz, z., lutz, h.o., krajcar bronić, i. (2008): note on the spring region of the gacka river (croatia).− isotop. e nvir. health studies, 44/2, 201–208. available online april 01, 2013 geologia croatica 66/2geologia croatica 152 geol. croat. 46/l 7 1 90 14 figs. i i zagreb 1993 i udc 551.312:551.79(497.13) original sdenl ific paper alternating lacustrine-marsh sedimentation and subaerial exposure phases during quaternary: precko, zagreb, c,·oatia josipa velie and goran durn key words: pl eistocene, holocene, lirnnic, paludal and fluviatil e depos it s. loessoid , palaeoclimate, paiaeosol, conditional marker hori zon q', precko, zagreb abstract wo,;sl of zagreb, v. ithi n an area of (1 ha , four units to!illling 60 iii thil'knc:.s have heen recognilcti 0 11 the ba:;is o f ('ore ana lysis, go.:ologt­ call1lappin g, gcllphysic'llmcasur.:mcn ls in explorat ion well s and lah­ or.lloi)' an:llyscs. '11l.! deepest situated unit (l~ni l i) aco.:u nwlatcu jur­ ing the i.ower plci!'. toccnc. it is inte rpreted to have fonned by accu­ tllula!i\)11 of i ~)ess mixed wjlh local mat eria ls (loessoij ). unit it is cons id e rcil ii) he midd!.: pleistoce ne in age. while in its luwer and nliddlc pan fluvlati\c · lacustrine sed im en ls are recognil.cd, in thc ll!l!lcr lxll1 aci)! i;l n illa! eria l coll!ribu!eu to the t'ompo~i t ion of the sedi ­ ments . this un!! is ove rlain by unit iii whidl is consi,kred to b¢ upp,.:r pleistocene in age. 'nw composition of thc ullil is jolllin:h cl ! uy 11l,liaial of loess origlll, and is interprctej to havc fonncd in a marshy cnvironlll cnt. th.:: young.::st unit (u nit iv) is composed of iloln..:cnc fluviatilc l'cdilllo.:n ts. "i"ho.: llpper parts of un its i, ii and [[i display palaco~ol fealures injicating ihal wcre subjccted 10 ihe a";lion o f soil folllllng prot.:esses junng phases nf suixlerial exposu re . thcs\: occuro.:u as a rcsull of lake/mar .. h in fi lling whidl happened ju ring the ci)ld and .if)' gbdals :md prohab!y lasted dunng the olde r l~rioojs of int c rgt.j.ciab. re:-'ulllption of shal low and quiet woller cllvironmen ts llunng the younger pe riods of intcrg lacials is (."ongnums wil h the illcrca!'>cd influcllce of humij ity. t he fo nnalion of bot h, si"lo.:clfi.: s<!lli­ menlary environments and phases o f suhaeri al cxposurc was also innuenco.:d by differently di sp1:jycd neotectonic ;lclivity which was only pailly conll"lo.:nsated for by sedimentati on ami delludalion respec ­ tively . i. introduction drill ing and geophysical measurements undertaken within an area of 6 ha south of precko (western zagreb, fig. 1) have allowed the study of the lithological coill ­ posi tion, pal eoenvironmental reconstruction and srrati ­ graphic relationships of the deposits. in part, this paper represents an ex pansion of investigar ions caltied out by velic & saftic ( 1991) 10 kilometer westwards, along the left bank of the sava ri ver. in the vicinit y of its confluence with the krapina ri ver. they defined the condit ions and processes of formation of the middle pl eistocene illiviatilelaclistrine hnd holocene tluviatile deposils. kljucilc rijcci: pleistocen, holocen, lilllnicke, palu­ dalne i tluvijalne taloiine, lesoid, paieoklima, pale­ otlo, livjetni reper q', precko. zagreb sazctak zapadno od zagreha, na povrsill l od 6 ha na ~1..;rlovi rew li :lfa bll~e llja, geofizickih mje renja ii busotinama , tercnskc dctenllinacije i laboratorijskih analiza, r,lllucene sll celiri jcdinke do tl ubine 00 60 ill. najduhlja, jedilllca i nasla!a jc tijekolll jonjcg pleisloccna ll akup l ~ janjem 1csa liz mijesanje s inkalnilll lllatcrijalo])l (lesoi j). lcdinica ii jc srednjop1cislocenska. u donjc1l1 i srcdnjclll sl1 dije lu z:l stuplj cni rijccllo ·jczerski, a u gnrnjc t)} sve vise i eol..;ki scd im enti . slijedi jcl!illica ill , gomjnp1cislocenska, uominantno ! c~ l1()g podrijella, aku~ illulirana ii ill~)cvari. najllllada j..: jedini'::l iv , izgr,ldena oil holnccn~ skog rijc'::nng nanos;l. vr.~lii dijclovij eji nic;l!, ii i iii i1llaju i'.l1aeajkc paleotala buduci su bili il.lo1-cni pejogc llcz i. kopncn c fal.c sli rci'.ultat za punjav:lnja jei'.c ra/l11ocvara tijc kolll hladni h i su hih gladjala, a tra­ ja1c su t stano\'ito vrijelllc k roz s larija rat-doll!j a inlcrgla..:ija!a . suk ladno svc vccem iltjccaju hulllidi tel;j, lj mladilll r;l'ldooljilll;l inter· glacija la ounavljane su plilke, ;llimc "oelenc sretline. na up naslaga i pojavll kopncnih fa'l';l uljeclla jc i ralli c ito laa1-cii<l lokaln:l llcotck­ \on ... ka ;lklivllost koja je sa1110 ilje lom i..::c kolll l"lo.:ll/j rana sejil\l cll t aci~ jonl, oonosno dcnudac ijl)m. many reconstructions. especia ll y for ih e late quatern;uy, based on continentaj hydrolysis. sea water and general temperature are availab le for marine records (e.g. rotschy et ai. , 1972) . compared to ihe continent.al environments, slich as cave fillings, tluvio­ glacial. or tluvio~ lilllnic deposits, they indicate a clear sequence of depositional history. alt hough mainl y of local significculce, results based on the in vestigation of specific continental environments, accompan ied with observed lateral and vertical changes can undoubtedly increase a level of knowledge of events thm have taken place during quaternary. the area of investigation represents a low land, aver­ aging 120 rn above sea-level. covered by meadows and mabie land. seven exploration well s were drilled: fom r .. ..::u lt y o f ~ining, geology and pe troleu1ll enginee ring, pi~rollijcva 6, 41000 zagreb, croatia. 72 fi g. j localioll map. s]' i polo:i.ajna ":l11 a . o , 50 lao km .....i i along the left bank and three along the right bank of the sa va ri ver (fig. 2). a total of 390 m of ex ploration core illclleri:l1 was extrac ted and anal ysed. more th~hl 30 sa mples were collected fo r laboratory inves ti gations. natural and induced riluioactivity measurements were al so undertaken. geophysical mc:1surcmcnts conducted in the study area indic:uc the ex istence o f four di stinctive units which coitcspond wilh the litholog ies ascertained from field ;ljld drill core illapping. zones with features indi­ cating the influence of soil forming processes can be defined. it has 10 be stressed that these zones arc closely related to the boundaries which were observed between the units. the related liliits are characteri zed by specific granulometric composi tion. pebble litho logies, relative frequenc ies o f occ uitence of se lected heavy minerals anel, p;utl y, bulk ,mineral composition of sands, ~ ilts and silly-clays. the stuely recognises specific characteris tics as the consequence o f seciimcnt;llion in different envi ­ ronments and paleoc limati c condition s and , postsedi ­ mentary processes during the phases of subaerial expo­ sure. 2. review of results ac ilieved fiy previous studies already at the beg inning of cen tury the idea was stated that yell ow (lnd grey coloured diluv iulll deposits of the savel plain represented sed iments of marsh or lake env ironments th at had exi sted si nce the u pper pliocene (gorjanovic~kramberger . 1908). a fter 1908, investi gations of the quatern;uy sediments, loc<lted in the zagreb environs, proceeded in two direc­ tions. h ydrogeo log ical in ves ti gati ons (m iletic & borcic. 1967; nov inska el ill .• 1967; borcic el gci)if)gi~ cro;llic:l mi/l fig. 2 lu.:aliotllllapnfw..:lls . ugl! lul: l =wl!ll. st.2 kalla raspi)f";i!a hu ;lilill :l . i .cg..;nl ia : j=o/.l1aka i .a bu;:'olinll . ai. , 1968; caka ru n e l a l. . 1987) focu sed o n gravel hori zons while others concentrated on petrological and stratigr:lphical problems. it has been es tablished that in the vicinity of precko, the s:ljldy-silty-clayey. meter th ick superficial deposit is underlain by several formations; all approximatel y 10 rn thick , predom inantl y coa rse-grained gra ve l overlies a brown. gra ve ll y-clay and 1iih..icr ly ing. greasy, grcy ish­ blue clay, sim ilar to the young pli oce ne and the z:lgreu ple is loce ne le rrace de pos il.'. crn kovi c & busi c (1970) pointed out the ckar dependence of tile illincr­ al ogich i-pclrographical composition of ihe sav:, ri ver del.)qs it ~ on the litholog ic.1i composition of the drain:lge area. between zapre!;ic and rak itje, cobbles o f mainly dolomite-limestone composition are found. w hile due ea ~ [ , w ith th e rt ppea rance o f greenschi sl s from mi. m edvednica. the composition of cobbles changes, w ith qu:ut z being more frequent. us ing factor analy sis. raffaelli & muti c ( 1982) separalecl heavy miner­ ai assemblages and concluded, that the material , salll ­ pled in the u pper plioce lle ple j ~ t ocene deposits, 15 kill due southeast of precko, predominanrly origin,licd from the metamorphic rocks of. mo~t l ikely , m i. moslavacka gora ~nd is partly of :leolian orig in . sedi mentation of the material took place in a quiter environment. the ill ost detail ed study on th e quaternary sedi ­ m ent s situat ed in th e z~g re b env irons is th .. n o f simun ic & basch ( 1975). in 120 m ex pl oration core material, they recognized four horizons of maj"shy­ loess and three hori zons of flu viatile deposi ts which me considered to be from the riss to the ii i \vlinn stad ial in age. s ikic e l al. ( 1979) a nd sikic & basch (1975) consider that detai led division of the plei stocene depos its of the western p;u·t of the zagreb environs is imposs ibl e, <lpart from divi sion into genet ic ty pes, which are pondy-loess, cont inental loess w ithout car vclie & dum: allc m31ing l3cuslrinc-m:h~h ... bonates, alluvial deposit of the third sava ri ver teltl\ce and cave~ fillings . during the plei stocene, pondy-loess was deposited in lake-remnants and/or ponds wi th a periodica l flu vial inflow. the quil ternary deposits investigated in prev laka, <liang the savel ri ver , located about 45 kill due west of precko. :lre :l lso documen ted in detail. a lthough located distant to the position of the present study, thi s area li1ust be discussed. while hernitz et nl .. ( 198 1) emphasized th:li the holocene and upper pl eistocene deposits together, arc lcss than 20 iii thick, simunic et "i. (1988) pointed out that 73 111 of upper pleistocene deposits are overlain by 2 to 3 rn thick holocene sedi­ ments. results of the in vesti g;:liiojls perform ed under­ line the difficulties and dilemmas concerning the chronostratigraphic subdiv isions. 3. ~ietiiolloi.ogy on the basis of descriptions performed and intervals observed. a qui te limited number of representative sam ~ pies were taken and subjected to different types of ana lysis. grilll ul omelric analyses were obt"ined by wet siev ing and sedimentation balance. petrogr<'lphic deter­ minations of sandy ~grave ls and gravelly~s;lnds ( 17 sam­ ples) were achieved by establi shing relati ve frequencies s 569 700 5 569 800 5559900 5570000 73 of occultence of cl<-'l st lithologies in the fraction> 4 hun . in addition , thin-sect ion analyses of selected peb­ bles were pelformed. the 7 1 to 125 >,111 fraction of the selected silty-&1n<ls and silts (15 samples) was quantita­ ti vely se parated into heavy and light f racti ons using ijromoform. in order to determine the relative frequen­ cies of occuitence of the mineral s, counts of the grains were made microscopically. xrd-da ta of se lec ted sands. silts and silt y-clays (13 s,"nples) were obtained using n phillips x~ray diffractometer unit. w ith ell k a radiation generated <'it 34 ky :in<l 18 ma. scmiqu<'intit<'ltive estim:-ltion of mineral content was per­ follned as wel l, micropal;leontological investigations of se lected silty-sa nds were also unden"ken. during explor<llion. wel ls were measured for natur:c, l clnd induced radioacti vit y. in :ldditi on neutron log mea­ surements were performed. \vhile an excellent verti ca l resolution has been achieved with the natural rad ioac­ ti vit y measurement s. onl y the neutron curve confirmed the existence of some horizons on a i imited scale, wi th increased moi stness or ground -wa ter saturated hori ­ zons. allhough the limited number of s:lillples and analy­ ses made interpret:liion spor:1di c:lll y difficult , it has been compensated for by an interd isc iplinary synthesis of the results obt<'lined. 4. lithological description of units 4. 1. introduction 5 discrimination of units is based on all the field and 20 22 24 bp-s j pp-2 ~ 0,1 legend : 1 ~ l egf!nda : t 22 bp-4 ~ o t km i 20 fig. 3 isopal: il map uf unit i!. legend: l = i ~opach. 071 0 900 iaborarory delta. n the basis of core determ inations, 5 071 '00 5 071 700 5 0 71 '00 b 500 results of applied laboratory analyses and average nat­ ural radioact i vity, four units can be recognized. a 13 to 25 meter thi ck interv,"ll of u nit i was encountered in all wells. but the base of the unit was never determined . during the field work, certa.in char­ acteristics were noticed which clearly distinguish this ullit from the overlying sediments. these are a grade of diagenesis, uniform granulometric co mpos ition and colour. the unit is composed of yellowish-orange, yel­ low ish-red and yellow ish-brown. se llli ~ lilhifi ed , com­ pact clayey-silts and silt y -clays. g rey coloured or brown ~ mottled. meter thi ck interbeds are present , together w ith a few decimeter thick lenses of s:culd , and a minor amount of gravels. unit ii i s of relati ve l y un iform compo sition. sj. 3 karta d..:h ljinc ii jcdinice. legenda: l =li llijejcdnakih dchljina . ranging in thickness from 10.35 to 24.3 iii (figs. 3, 6 and 14). the lower part of the unit is predominantl y composed of grey-coloured sands. upw(lrds. the con­ tent of silt and clay sized material becomes significant. unit 1 is directly overlain by 0.5 to 2.5 iii thick gravel­ iy ~sands, containing tip to 33% gravels. their base is sharp , and they pass upwards into sands with varying proportions of silt. in the middle port of un it ii , a 1.5 to 3 111 thi ck. sellli ~ lithi fied layer of normally graded grav­ ell y-sand is present. which grades upward into fine 74 sand. the upper part of the unit is dominated by grey­ coloured or, less often, red to yellowish-brown mottled silt and clay sized material with weathered carbonate concretions. unit iii is heterogeneous and varies in thickness between wells, as shown on fig. 4. the minimum thickness of the unit was observed in exploration well bp-5 (6.5 m), while the maximum thickness was found in bp-3 (13.2 m). the oldest (and basal) member, a poorly sorted mixture of gravel, sand and silt, (-33:33:33%) was observeci only in two wells. elsewhere, the base of the unit is represented by clays and clayey-silts. in wells bp-2, bp-3, bp-4 and pp-l, these sedilnents are overlain by sands which become progressively more silty. in distinction from those pre­ viously described, in wells bpi, bp-5 and pp-2 the lower pm! is silt dominated, while younger intervals are more sandy. the colour of the unit is not uniform. while the sands are predominantly grey-coloured, the silts and clays are often mottled yellow and brown. the uppermost, 10 to 70 centimetres of the unit, as observed in 6 wells , is rusty to yellowish-brown in colour, and the boundmy with the overlying unil iv is characterized by the abrupt apretlrance of gravels and sands (figs. 6 ancii4). the youngest unit (unit iv) varies in thickness from 6.6 to 7.7 m (fig. 5) and is of a simple lithological 5 '569 700 5 569 800 5 569900 b;3-3 \ 1zj 11 __ 10--bp-1 " pp-i o ~ ~/0 h j~p-z \, o 05 legtnd : legf'nda : 1~ bp-, o 9 lkm fig. 4 isopach l11ap of unit iii. legend : i=isopach. 5570000 5 071 900 5 071 '00 5 071 700 5 071 .00 si . 4 kart a tkhljine jejinicc iii . lcgcnda: l=linijc jcdnakih debljina geologia croatica -1(,/1 composition. in wells pp-l, bp-3 and bp-5 carbonate gravels, comprising well rounded cobbles of up to 7 cm in diameter were recognized, accompanied by pale, yellowish-grey sands. e lsewhere gravels and sands are overlain by a greyish-brown, fine-grained silty-sand, less than i m thick, with rare cobbles of carbonate composition. the brownish colour is a consequence of the presence of carbonized plant remnants. the oiigin of a ciesn-oyed peat is possibly related to the adjacent subrecent marshy areas which were incorporated into a fluviatile-type environment. the general lithological characteristics of the units described above coltespond to, and are retlected in the geophysical signatures of the sediments (figs. 6 and 7). however, trnces observed from different welllogs can indicate illutually opposing tfends for zones of simil.;-tr age e.g. unit iii, wells bp-5 and bp-2 (fig. 6). in addi ­ tion, the pattern of the gamma log can, in some instances, be directly related to the litholog ical compo­ sition. for example, these traces in unit iii (see well bp-5, fig . 6) form a funnel -like pattern in the lower part of the unit, diverging into a bell-shaped pattern in the upper pari. these patterns coltesponcls to increasing gravel content ill the lower pmt of unit ill, and the higher sand, silt and clay content of the upper pm'! of the unit. as observed in figs. 6 and 7 the boundaries 5569 700 bp-5 a bp-j a '5 569600 pp -z a 5 569900 pp-i o bp-i o 5570000 s 071 900 , 07 1 000 ~--~5 bp-' a 5 071 700 5 071 '00 l ____ ~~o:.::::::~::o:,5::::::::::~lk_m ______ ~~71 500 legend; legenda : 1~ fig. 5 isopach map of unit iv. legenu: l=isopach. si.5 karta debljine jedinkc iv. lcgcnda: i =linije jcllnakih dcbljina . velie & dum: ahematin!!; lacustrinc-m:lrsh. 1m ) '25 120 11 5 110 105 100 95 90 b5 so 75 70 bp-5 bp-2 11' neutron log gamma gamma log fig. 6 welllogs ltoss-currclation bp-s bp-2 bp-3 ppl sj. 6 shclll atski bnclacijski profij br-s bp-2 op-3 pp1. 1m) '25 '20 115 11 0 'os 100 55 90 65 75 70 " pp-2 ,----, gamma.! log : 59° i---neutron log gamma-gamma log bp-4 fig. 7 well -logs cross-correlation pp-2 bp-4 bpl . si. 7 she[llatski korelacijski profil pp-2 bp-4 bp-l . bp-3 pp-1 60' bp-1 10' q' '" z '" iv g .... o ::t iii '" z u ii 0 .... '" iv ffi u o .... o ::t iii z ii u o iui .... 75 76 5569700 5 569 sao 5 569900 5570 000 86 85 b~1 84~ o 83 82 81 8p-s 800) ll'g~n d: legenda : pp 2 o 0,5 80 fig. 8 (\)llh)urmap base of un it ii. lcg~· n.l: i:i!'ohyp!;e. 5 071 900 5 071 800 5 071 700 5 07 1 600 sl. 8 k:u1a 1'li.1lii nlike pll)l\.; jedinice ii. l...::gcnda: i =1inije jetlnal ih ap!'olurllih v isin:l between un its are not p~uallcl. reflecting lateral th ick­ ness variation of the units. this is al so c learl y seen in contour maps of the bound;u'ies (figs . 8, 9 and 10). the steepness of the slope of the boundaries (reflected by tile spaci ng of lhe contours) decreases for progress ive ly younger bolln d~u ' i es (compare figs. 8, 9 and 10). this is the consequence of a nullloer of f<lctors, including sedi ­ mentary environment s, sedimentation and denudati on processes. anel tectonic processes, anel is disc ll ssed fur­ ther below. 4.2. det ailed description of units in dr ill cores bpi and bp-4 a fter the detai led anal ys is of drill cores, wells bp~ i ~nd bp ~ 4, charac ter i zed the mos t obv ious lateral changes between contemporary units and were chosen for compari son. while drill core bp-2 di splayed quite a high degree of similarity on granulollletric and mineral ch:mlcteri stics wi th dri ll core bp-i, drill core pp-2 di s­ played the same with drill core bp-4. these facts were used in order to supplelnent and exp<lnel the data. vllit i bpl drill core was tennin;lied in unit i at a depth of 39.2 111 recording a thickness of 15.8 111 , but the base 5569 700 5 569 900 ~p-~\ 99~ 100 101 ____ _____ o bp-2 o gcolngi:1 cro:lli<;a 4(,/1 s sf>99oo pp-t o ------\\)'1bp-t bp 4 o o i km os 570000 5 07 1 '00 5 071 '00 5 07 1 700 5 07 1 500 5 071 ~ ____ l_~::::::~::::::::==~::~ ______ ~500 legend: leg~nda ~ fig.9 contour 111.l p has..: of unit iii. legend : l = i ~(lhypsc. si. 9 ka rl a pod in .. ke plohc j,;d inc..: iii. lege nda: 1=li nijc j..:dnaki h apsutlltn ih \·i .. ina of the unit was not determined (fig. 13). in ascending order the unit consists of: 55.0 53.9 rn , predominant ly yellowish-brown mot­ tled, grey-coloured cl::lyey-silt with sporad ic quartzite and s(uldstone granu les. 53.9 50.0 m, ye llow i, h-brown cb y anel ye ll owish­ brown mottl ed silty-clay with sporadic pebbl es. 50,0 49 .6 ill , predominantly yellowish-brown mot­ tled grey clayey-silt. 49,6 47.4 ill, yellowi sh-red silt y-clay wilh sporadic gran ules in the lo wer part of the leve l (lnd ab ljndant quart zite and sand stone pebbles ill the upper parr, 47.4 45.3 fl 1. ye llow ish-red , silt y-clay to clayey-s ilt with sporadic quartzite and sandslone pebbles, a thin interbed in the lower part of the leve l represents green­ ish-grey to brown, poorly sorted gra velly (0 silt y clay. the fraction >4 mill contains inainly quartzite (68 70) ~lnd sandstone pebbles (26 ('/0). ex trusive rocks , tuffs and schists contribute a few per celli each, the heavy mineral fraction contain s opaqu es (62%), epidote (23%), zois ite (7%) , tourmaline (3%) , eli"hene (2%), zircon, garnet and apatite ( 1%). 45 .3 39.2 m, yellowish-recl mottled silt y-clay with sporadic limonitic sflndstone pebbles . the illoo les men­ tioned are mostl y assoc iated wit h the upper part of the leve l. xrd -anal ys is showed that the ye ll ow ish-red vcli0 &: dllm: alterrntitlg [.:lc!lstrim'. :"b r~h ... 5 569 700 bp-5 o bp-3 o 5 569 900 pp -2 :::: 0 -o ltgtnd : legenda : l~ l1jd pp-l o bp-2 o bp-' o 5570000 5 071 900 5 071 eoo 5 071 700 5 071 600 fig. [0 contour lliap uase of un it iv . legcnd : 1==isohypsc. sl. 10 k;lj1a poo:\ in ske p1nhc jcdillice iv. lcgcil<1a: i=jinijc j..;,1t1<lkih apsollitnih visilla . mottled si lt y-clay cons ists of qljartz (38%), mic~ceolj s minerals (23%), k-feldsp;u· (2%), ch lorite, unidentified mixed-layer clay mineral , kaolinite and goethite, in drill core bp-4 unit 1 is 22 iii in thickness, but the base of the unit v·,ias not determined (fig . 14) . it consists of: 55.0 54.2 m, predominantly yell ow ish-brown mot­ tl ed. dark grey sil t with sporadic quanzite pebbles. 54.2 53 .8 ill , dark grey-greenish silt to fine grained s:l nd. 53.8 53.3 ill , dark grey co loured, sandy matri x sup­ ported breccia-conglomerate. 53 .3 -52.8 ill , fine-grained yellowish-brown mottled sand, fining upwards to grey silt. 52.8 43 .0 ill, ye ll owish-brown clayey silt with grey mottles 43.0 40,0 m, yellowish-red silly-clay to clayey-silt wilh sporadic grey mott les. 40.0 33.0 ill , grey silty-c lay to clayey-silt with yel­ lowish-red mottles. a sample taken from the upper pmt of the level conta.ins qu:u"tz (20%), micaceolls minerals (30%), dolomite (15%) , ca lc ite. chlorite, smect it e, mixed layer clay mineral and kaolinite. 77 un it ii in drill core bp i unit it is 23 .8 m thick, contact with the underlying unit 1 is sharp and is characterized by an abrupt change in granulometric composition and colour. 39.2 32.8 m, grey gravelly-sand and silty-sand, grad­ ing upwards to sandy-silt and sandy-c layey-silt. the heavy mineral fraction of th e si lt y-sa nd contains opaques (78%), gamet (7%), epidote (5%), zircon (3%), titanite, chlorite, di sthene, apatite, zoisite and tounna­ line (\ %). a sample of the sandy-clayey-silt consists of quart z (28%), micaceous mineral s (20%), dolomite (15 %), plagioclase (8%), calcite (7%). chlorite, smec­ tite, mixed-layer clay mineral , kaolinite and, poss ibly siderite!. 32.8 27.0 m, grey sandy-silt s overlain by alternating dm sized grave lly-sand layers and cm -elm sized layers containing silty-sands. the gnwelly-sand contains peb­ bles of quartzite (53%), sandstone ( 17%), chert (14%), limestone (5%) , dolomite (4%) and cong lomerate-brec­ cia (3%). a lso observed extrusive rocks, tuffs, and acid intrusive rocks contribute a few per cent together. 27.0 21. 5 tn, grey si lty-sand. consists of qu~u·tz (30%), dolomite (28%), micaceolls minerals (j2l'/c), cal­ cit e (8%), plagioclase (5%), k-feldspar and chlorite. heavy mineral fr(]cti on conta ins opaques (62%), garnet ( 12%), epidote (9%), zoisite (6%), chlorite (5%), zir­ con, amphibole, disthene, apatite and tit~nite (1 %) . 2 1. 5 19.9 ill , ye ll ow ish-grey sa ndy-s ilt with thin interbeds of silty-clay. one of the interbeds contains qljartz (22%-), micaceous minerals (25%), dojolllite (20%), calcite (5%), k-fe ldspar (3%) . chlorite, smectite and mixed-layer clay mineral. 19.9 19.0 111 . greenish-g rey sandy-clayey si lt w ith carbonate concretions. 19.0 18.0 m, predominantl y grey clayey-s il t with yellowish-brown mottles, carbonate concreti ons nnd rem~tin s of rhisoconcretions. 18.0 15.4 111. ye ll owish-llrow ll 1i10ttied clayey-silt with cnrbonnte concret ions. tn drill core bp-4, u nit 11 is 16.6 iii thick. contact with the underlying unit is not sharp but distinguishes itself with a marked change in colour. 33.0 31.0 m, grey sandy-si lt 31.0 28 .0 m, li ght grey sandy-si lt wi th rare pyrite crysta ls. t his passes upwards to grave ll y-sa ndy-si lt with th in greeni sh -grey interbeds of si lt. a silt sampl e contained quartz (16%), micaceous mineral s (10%), dolomite (30%), calcite (15 %), plagioclase (3%), chl o­ rite. mixed-layer clay mineral and, possibly siderite. 28.0 26.4 rn, grey silty-sanely grave l. the fraction> 4 mm co/llains pebbles of sandstone (36%), quartzite (49%) alld chert ( 12%). pebbles o f ex tru sive rocks, tuffs. acid intrusive rocks :md schi sts, contribute togeth­ er a few per cent. 26.4 22.9 rn , grey silty-sand. the heavy mineral t according tl) xrd uata, ab~crvcd u ni dent ifieu carbonate minerals, noticeu in some sam pl es can ix l"<:t"crcd la sidctito: in whi ch iron is part ty r..::placed with calciutll and tllanganese (prof. d.slovenec, personal colllllllltlicatian). in the further t~xt, tenn possible sid~rite will he used. 78 fraction is composed of opaques (79%), epidote (7%), zoisi te (5%), garnet (4%), zircon (3%), tourmaline (i %) as we ll as apatite, chlorite and disthene (contributing less than a per cent each). the mineralogical composi­ tion of the upper pmt includes quaj1z (40%), micaceous minerals (8%), dolomite (28%), calcite (6%), plagio­ c l'tse (5%), k-feldspm (3%) 'uld chlorite. 22.9 19.7 m, as the underlying material but with an increased silt content and thin sandy-si lt interbed. 19.7 16.4 m, greenisll -grey sandy-c layey silt with sporadic pebbles and irregu lmly distributed cmbonate concretions. unit iii in drill core bpi, un it iii is 7.7 iii in thickness. the bound,m"y with the underlying unit is emphasized with a marked change in colour. 15.4 14.7 m, greenish-grey sandy-clayey-silt. 14.7 12.7 111, greenish-grey clayey-silt. the mineral composit ion includes quartz (38%), micaceous minerajs (25%), plagioclase, chlorite, smectite, mixed-layer clay minerals rmd kaolinite. 12.7 11.2 rn, greenish-grey sandy-clayey s ilt with sporadic plant fragments. 11.2 9.5 ill, grey sandy-silt with ostracodes and rema ins of lifhoglyphlls sit uated near the top of the sequence. 9.9 8.7 m, yellowish-grey silty-sand. 8.7 8.4 m, grey silty-sand. 8.4 7.8 tn, silty-sand, yellowish-brown mottled in the upper part, yellowish-brown in the lower pmt. the heavy mineral fraction contains opaques (43%), gamet (25%), epidote (9%), zoisite (5%), chlorite (5%), apatite (4%), zircon (3%), tourmaline (1%) as well as disthene, rutile, titanite, staurolite and sillimanite. in drill core bp-4, a 9.6 m thick unit iii was encountered. the boundary with the underlying unit is sharp and marked by an abrupt change in granujometric composition and a s light change in colour. 16.4 15.4 tn, grey, ungraded, sand dominated mix­ ture of gravel, sand , silt and c lay with a pyritized frag­ ment of wood. 15.4 15.0 tn, grey silty-gravelly-s:md with pebbles of dolomite (3%), sandstone (25%), qumtzite (45%), ext rusive rocks and tuffs (6%), chert (13%), and some acid intrusive rocks ;md schists. 15.0 10.4 m, grey si lty-sand with a brown coloured interbed containing plant remnants and fragments of wood. ida 7.5 m , grey silty-sand. 7.5 7.1 m, greenish-grey c layey-silt with irregu lmly distributed carbonate concretions. 7.1 6.8 m, silty-sand with pebbles in the upper part. unit iv unit iv, co mposed of sandy-grave ls, ranging in thickness from 6 .6 to 7.7 m , sh,"pl y overlies unit lit. diso'ibuted over the whole study area, sandy-gravels of grey, ye ll owish-grey and greyish-brown colour are composed of vmiety of rounded and subrounded pebbles set in a s ilt y-sand y matrix. pebb le litholog ies include limeston es (49 55%), dolomites (5 2 1 %), sandstones (ii 23%), quart zi tes (8 13%), chells (28%) , extru s ive rocks rlild tuffs (up to 5%), and con­ glomerates, breccias, acid intru s ive rocks and schi sts (contributing a few per cent each). 5, results 5.1. granulometric analyses unit i is laterally uniform and composed of s ilty­ clays and clayey-silts, with randomly distributed gran­ ules and pebbles. in the lower and middle parts of the un it , few sandy and gravelly-sandy layers were observed. unfortunately, only a small number of sam­ ples were anrllyzed, so, the description of unit 1 is b::l<.;ed ma.inly on field observations. the results of particle size detennin;ltions of units 1i , iii and iv, in drill cores bpl and bp-4 are shown on figs. 13 and 14. unit ii is laterally homogenous and characterized by the presence of one or two gravelly­ sand seq uences. in the upper part of the unit, abundant si lt size material, accompanied by an increasing clay content is observed. unit iii d isplays ',nore lateral vari­ ation. while drill core bp-4 is dominated by sand size material, in drill core bp-l, the lower and middle part is characterized by a high si lt content. unit iv is later­ ally uniform and composed of sandy gravels. the predomin<lnt occurrence of silt size material, observed in certain intervals of units i, ii and iii, raises the possibility of loess contribution to the sedimentary basin. for the determination of sedimentmy environ­ ments based o n particle-size distribution, the correla­ tion of the parameters med ian, coefficient of so rting and skew ness have proved convenient (kukal, 1971). according to kukal (1971), the median (mel) of loess is usually 0.06 0.02 mm, the coefficient of sorti ng as phi deviation is 1-3 and phi skewness is in most cases sl ightly pos iti ve. 1n his figures, the coeffi­ cient of sorting and skewness of the sediments ;ue coi11pared with their median. the statistical parameters of the silt samples are plolted in fig.12. the diagram is modi fied after kukal (197 1) and nll-llen & soly­ om (1986). it is obvious that the loess influ ence can not be neglected. sand, or c lay sized material can be attributed to the mixing with local materials or to pedogenic processes. according to pye ( 1987), the term " ioes­ said" can be ll sed to describe sediments composed of mixtures of deposited dust a nd other (local) sed iments (such as dune s.md, soi l, alluvial fill) . he also e mpha­ s ized that the term " loess-like deposits" can be used for sediments which possess many of the sed ime ntological properties of aeolian loess but w hic h have not been transported by the wind at any stage in the ir hi story (such as overbank s ilts and some colluvial deposits). loess is frequently but very often a mi s-used term in velie & dum: ahemating i~'custrille marsh ... our literature. in tltis paper, for sediments having the propej1ies of loess (mainl y based on particle size analy­ ses and analogy with the l iterature), reworked loess and resedimented loess, the term loessoid sediment is used. 5.2. pebble lithologies on th e basis of pebb le lithologies, two different types of gj'hvelly sediments can be recognized. type i includes the si lty-grav elly sands of unit iii , gravell y­ sands (llld snndy-silty gravels of unit ii and gravelly­ sandy interbeds of unit 1. they are of siliciclastic com­ position, comprised mainl y of quartzite and sandstone granules and pebbles set in h clayey-si lt to sandy ma tri x. while in units ii and iii a few pebbles of lime­ stone and dolostone were found. no h'ace of carbonate pebbles was observed in unit t. type 2 deposits are represented by the sandy gravels of unit iv, composed of rou nded and subrounded pebbles of predominantly carbonate composition (l imestones and dolostones) in a silt y-sandy matrix. the difference, emphas ized by the pebble litholo­ gies of the two types suggests that during their forma­ tion, di stinct source rocks were exposed to erosion and weathering. in addition, it can be stressed that , general­ ly. morc limestones and dolostones were eroded. acting as a progressively dominant source of pebbles for sed i­ ments of increasingly younger age. 5.3. hea vy and light mineral composition the heavy mineral assemblages me comparat ively simple. samples selected from units i , ii and iii con­ t.lin opaques. epidote, garnet. zoisi te. chlorite and zir­ con with smnll amounts of lounnaline, apatite, amph i­ bole. di sthene, titanite, staurolite. biotite and silliman­ ite. a complete absence of pyroxenes, together with the sc:u sity of amphiboles may indicate that intensive abra­ sion and/or weathering have taken place, suggestin g that sediments are reworked. in addition, it is possibile that the source rocks did not contajn these minerals in any di stinctive percentage. heavy mineral percentages in a particular unit are comparable for equivalent depths. a difference between the g:unct and epidote content among the units was observed. in order to compare the heavy mineral coil1position alllong the units, data <'ire plotted in relation to epidote, zircon + tourmaline and garnet (fig. ii ). the foflllcuion of three di stinct groups suggest, thai, possi ­ bly, different source areas and/or different transport fac­ tors were in volved. the light mineral fraction consi sts of variable por­ ti ons of quart z, feldspars (mainly albite, rarely k ­ feldspar), muscovite and calcite (as mineral and lime­ stone fragments) . it is necessary to stress that in the yel ­ lowish-red mottled silty-sands of unit i , calcite was not found. 79 5.4. palaeosols "palaeosols are soi is that formed in the past on por­ tions of land surfaces that were sufficientl y stable for variable lengths of time to recei ve and retain imprints of soil forming factors'" (lecki e et ai. , 1989). einse­ le (199 1) stated that lake deposi ts are frequently asso­ ciated with fossil soils. according to kraus (1987), palaeosols in alluvial sed iments me powelful indicators of pal eoclimate, floodplain drainage and pauses of sedi ­ mentation. in order to establ ish whether certain intervals repre­ sent palaeosols. the following criteria were used: different colour compared to the over lying and underlyi ng material. presence of mottles, presence of concretions and nodules, evidence of progressive weathering of minerals. presence of roots and organic matter frclgmeilts. on the basis of the above criteria. at least three intervals are of possible pedogenic origin. these inter­ vals afe closely related to the observed unit boundaries. they indicclte that the upper pm"ts of the units were sub­ jected to soil forming processes. however, it should be noted that some diagenetic features (for instance, burial gleying) closely resemble that of soil s. , , ion l'oiil~ : l~g~nda : , " • • .' .' , n' o , too \ , , d 0 zircon .tourmaiine .... too\ ,gj,gj,gj·gj,gj ·gj 'gj'~ {~}o0 fig. ii composition of selected heavy mincrats. l.t:gcnd : l=well fip1; 2=wdj i3p-2; 3=wcll fip-3: 4=wc ll bp-4; s=wcll bp-s: 6=well pp-i; 7=wc ll pr-2: 8=unit i; 9=unit ii: 100unit ill . sl. i i sastav izabrani h teskih illinerala. lcgcnda: i =hu sotina bpl ; 2=busot ina op-2: 3=bu ~otin dp-3; 4 = busotina bp-4 ; s=busotin;l bp-s: 6 =bu sotina ppl ; 7=busotina pp-2; 8=jedinica i: 9=jcdin ica ii ; io=jcdi ni ca iii. so 5.5. geopii ysical well logs the gamma log trace represents a li thological indi ­ cator as well as a iih:' lliod of performing corrcim ions. for the q uate rna ry sed ime nts in north croat ia , thi s method is suitable oo[h for cased alld uncased w~ li s . ii facilitates very good gene!":l l lli scrimi nation of clayey­ silt s, sand s and grave ls rc:-' lk 'cli veiy : the first are recog­ ni zed due 10 hi gh radi;liion, d ue 10 the pre ~ell ce of potass ium frolll fe llhpars nlld 11ii caceolj s m iner;l ! :; (grain s and c j a~ t s of ~ollrce rocks), the second ;m,::: idell­ tified by mediul1i radi:lli on brought out hy the d:1 111p ing inlluence of noll radioactive quartz and the th ire! pro­ duce very l ow leve l s of rad iation from ca rbona tes which constitute the rn:ljority of pebbles in the youngest gravels. the gmnma log traces, obtained from seven expl o­ rati on well s, corroborate the ex istence of fou r iillit s. thi s c:1n be ck:1rl y see n in explorm ion well ppl (fig. 6) . the olde~ t ujlit i ~ characteri zed wi th an average of 30 count s per rvlinulc (c ptvl) , ullit ii with an average of 15 cpm (exce pt in leve l s wi th hi gh s;ulli con ten!. h:lving r cpm), uilit 1][ wilh an average or :w cpm :lj1d unit iv , in genell!. \vith.5 cpm. t he :,hape of the neulron log reflects the qijw1tit y of hydrogen in r ock s penetrated by explor at ion well . therefore, the neul ron log is used for lll e'l.<; urin g ill ois­ lure auo\'e ille water tabl e ~\ild 10lal porosit y tx',low the wat er i:lo le. the it ig he~ t results. as show n jn count per second lln i t.\ (c ps), coincide w ilh w<u erl>earill j;. gra vq 4 a , , , . , • j , • , • ~ , 12 • 2. 1 2z~ 1, . f.$rot~ j 'l6 , c.l z ·r~ .~' / t i , , , , , , , , • , • t i mel . eb of unit i v and mo ist. sandy inter val s of un it ii (figs. 6 and 7). 6. interpretati on (, .1. sedimentary environments and phases of suba erial expos ure the evo luti o n of th e lillit s inv es li g<ll cd \vas undoubtedly dependent upon g laci:ll/i lll erglacial cycles. il is a comlllon belief that during tile glaci:ll pe r iods, a !;lrge :1jllount of wind borne sill material ( loess) was bl ow n olii and accuillulated :-'olllll o f til e glac iated regions, build ing extensi ve " eolian loess dcpo.'~ j t s . a s si lt size mate rial is prcuominan t in the cores invest igated, an auempt was ilwdc to fi nd out '.d letl1cr tile .sediments of uni t i were 1';111 1), composed or loess. sli ght ly too hi gh coenic i e nt ~ ur sorting com pared to the ave rage values (fig. 12). po:-.:-. ib ly ind icate the mi x­ ing of loess wit h local 1ll:li eri :li s ( ioesso id ~ccl illl e ll t). jlowcve r , ver y similar gr;l in !-'ize p:u :lil1 cter :, were found for flood plain ba s ijl ~ (k u kal, 197 1) \vhich during :1 wet and humid clim;lh:: incl ude i:lrge vegetaled marshes or sw<lmps hnd permall ent lakes nnd poilus (allen, 1971). a lth ou g h ge n e ti cal ly related to g laci:ll s, during: the more humid periods, 10l!ss is easil y eroded by running water and f1u vi;l l :lcli on ,hill ir;ln s~ ported as a reworked sediment to an <l cce~:-. i b l e sedi ­ mentary basin. during irallspoj l :is we ll as (kpo" itiojl . b ~i ~ -i , , " • !rl-2j 6 , 0 '~:~r>' 6 6 'l. 1 , ~'j. "~q" , , • .,0, v t / , , , • , • t • md + l a.t nd : ,[~,gj ,g] {~{~·gj ,g].[j] .[jjiow l ~9 ~ n da : j:jg. t2 a. ro.: l:l tion ixtwco.:n nl ..:di ;ln and the coefficio.:nl i)f sol1 i.lg . n . rdallol1 b..: tw..:cn lll ..:ui :ltl and ske wness. o utlin cd alill dash..:d 1.\) ilcs injicalc arc:is with ' ypic:ll1 oc..;s dcpo~j l s rati o~ . (lliojlflt!j afl..: r kuka\. . 1971 an d 1\'[111.(::;\ & solyom, 198(,) lcg..:nd: i=wcll opi ; 2=v. d j 81'-2; j=wdl dp-3; 4 =wcll dp-4 ; 5=\\..:11 fip -5; (,=""...:\1 pp. i; 7=wdl 1'1'-2; ~=c ni l l 9= unl' ii : io=l:ni l iii. sl . 12 a . od llos i 7jllcuu mcdijallil i k rl<~ fjcij ..:nla sor1 iranja. o. ojilds if'.ill ..:du ill cdijana i ko..:f icijcnlil asillleirijo.:. uo kvin.:n\! i isc l1kan(: 7.onr.: indiciraju j)()(lrulja lli111tar klljih so.: llala7.c ndllosi kn..: ficijc ­ niha 1.,1 tipi ":nc nasi age k sa . (rn ndific irano prmn;\ kukai", 197 1 i :\liill~n & so l yo m , 19r (,) \ ,cgl!li lla : l =hll~ ()[i l1a rp . i : 2=buso[ill:l rp-2: j =bll.~olina rp-3: ·1=busnlijl:.l flp -4 : 5=bu _(otill<l nr-s: 6=bll.~ul i l1a ppi : 7 =hu sutill a pp-2 ; ~=!.:d j lli cl1" qd.:liininlll : 1 00"~"i"!c .! .ill this reseclirneillcd jllaleria] can easily mix with other m;lier i:1is. undoubtedly. loess could have been blown directly to a sedilllen tary basin (lake, marsh, pond, river). \vincl blown dust and sand contribute to the com­ position of various types or sedimen ts which ultimately accumulate in fluvial or subaquatic environments (ein­ sele. 1991). the heavy mineral composition shows that. coill ­ p:-ncd to the younger units, unit i is depleted ill its gar­ net content (fig. ii ). this almost complete lack of gar­ net can be rel:li cd to the source area. [i' we assume doill­ inant loess origin of the unit , the difference ill garnet conlent gill also be rei:lied to transport. namely, the lack of the heavier garnet, colllp,l recl to the much morc nounciant lighter epidote ill;l)' imply that the source area w;ls silu;lied far ,l\vay from the depositional basin. with the exception of the silty-clays, a dominant ch;l ractcri :-.t ic of unit l at jeast ill its upper part, is the predom inantl y yel lowis h-red and yellowish-brown appe:u",mce of tile sediment s. xrd-diffr<lctograms sho\v rh ;.lt the yellow ish-red mottled si lt y -cl~iy , situ;ued in the upper part of the unit in the drill core bpi contains, among othe r minernl s, goelhite. the pr ese nce of goethite indicates th;li the sediment has been ox idized. the occultence of more than 10 iii thick ye llowi sh-red sediment in pl<1ces may sugge:-.t that the colour of the sediment : (i) is original, implying that the sediment \vas depos ited in a well oxygenated environment , (2) rcflects pos t -burial, po st-llepo sitional oxid~lljon processes, (3) reflects post· depositional weathering. togethcr, the yellowish -red 11101l1eo appe;jr;hlce, lack of carbonates and presence of goethite suggest til;h the upper part of the unit in the drill core bp-i was influenced by weathering, i.e. so il forming processes. accordin g to rettalack (1990), the geornorphic se ttin g. of p:1laeoso ls may not always be obvious, but their relationship to the water table often is di scernible and has a clear bearing on their position ill the lnnd ­ sc1 pcs of the past. the presence of ye llow ish-red mot­ tles in the prcdomin;llltly grey silty-clay, noticed in the upper pan o f the unit in the drill core bp-4, indicate that the pa leosol (and underl ying sediment) had been partly within th e zone of welter table fluctuation. com pared to the \vell drained yello\vish-red pal;leosol observed in the drill core bp-l, the grey onc contajns calcite, dolomite and smectite and lacks goethite (except in mottles). \ve suppose that, during the wet seilson, pal<leosol was affected by gleying processes. during the dry season (lower water table), liberated fer­ rous iron was ox idi zed and fixed as goeth ite on yellow­ ish-red mottl es . it is necess;u'y to stress that the features implying waterlogged conditions were noticed at differ­ ent levels through the prevailingly yellowish-red uni t l the origin of these features is disputilble. allhough indi sputable evidence for the prevailing yellow ish-red appearance of un it t is not available, existing fact s are suffic iently convincing and illlply thm at least the lipper p;lrt or the unit represents a palaeosol. in additioll , waterlogged features may indicate that sev 81 eral st:lges of wc<ltherillg or post-buri;il processes were invo l ved. nevertheless, the preserved ye l1o\v i sh -rcd appearance implies that oxidizing conditions within the unit were 1ll "1int;lincd bec;llise little or no org;lnic j\l:lter or reducing pore waters were avail:lble to convert the iron from a ferric to feltous sl<lie (elnsele, 1(91). according to karlstroom (1991). much evi­ dence suggests th:1t 1;1ie tertiary and pleistocene inter­ glacia ls in upper-ll1il1dle latitude continental reg ions were c1wracl crized by \\farm -tcmperate, sub tropical and/or meditermne;lil climates. at th;1i time, dirferent types of interglacial soi ls developecl. as palneosols gen­ erall y bem the imprint of the st rongest env ironment affecting their development (morrison, 1(78), we attribute the observed p(lleosol (lnd upper parts of the unit to be influenced by an interglaci;ll climate. the presence of pyrite and, pos~ibly siderite, as well as the grey colour of unit ii undollbtedly indicatcs that the sediment has been ;lllected by red llcing coihjilions. in addition, in drill core bp-5 the lower gravelly-s:lildy interbed contains very well preserved wood fr;lgrnents with abundant pyr ite crystals. vvhile in the middle part of the unit limestone ;lild dolomite pebbles can be found , in the sandy-gravels, in ihe lower pan no pebble of carbonate compos ition li;ls beell observed. a charac­ teristic featllre of the unit is the presence of a l!jlifonn , 3.4 il\ (ilp-1) to 5.5 iii (dp-i) thick. grey s ilt y-sand which ove rli es the gr;lvelly interbeds . although the upper p;1rt of unit is clwracterized by the silt dominated, fining upwards sequence, differences in colou r, thick­ ness and gr:lr1ulometric composition of the upperlllost part of unit , ll(ls been obser ved between cores. gra in size pa r;lm eters of the lipperm ost part of the lillit (fig. 12) indicate loessoid sediments and a lacustrine-illarsh type deposi tional environment. in ihe drill core bp-i, tile uppermost part of tile unit in decreasing vertical oreler is colllljosed of yellowish­ bro\\!11 1l10ttled clayey-silt wi lh carbonate concretions, underlain by grey clayey-silt wit h yel low ish-brown mottles. carbonate co ncret i ons and rell1n;lnts of rhisoconcretions, and greenish-grey clayeysilt with carbonate concret ions . t he clay content decreases dow!iw(lj"(ls. the vertical section described, and features men­ tioned strongly suggest tll;1i the upper part o f the unit was subjected to water table tluctllmions. vvhile the ye llowish-brown mottled clayey-silt <lccompanied with carbonate concretions resembles well drained soi ls , the underlying grey clayey-silt with ye llowish-brown mot­ tles and carbonate concretions indicates seasona lly \vet conditions. according to einsele (i (91), carbon:lte nodules originating from near surface carbonate disso­ lution and reprecipitation are sillli1m to the formation of caliche. retallack (1990) stated that ca lglreous . concretions are thought to have accumulated under alkaline conditions of dry period s. rhisoconcretions (observed in grey clayey-si lt) form in soi l s because of the spec ial local environment created by roots (retallack. 1990). as the result of re peated cycles 82 of wetting and drying, roots may become heavily encrusted with concentric layers of very-fine grained low-magnesium calcite. the presence of rhisoconcre­ tions suggest that the sediment wll~ subjected to repeat­ ed cycles of wetting and drying. although the appear­ ance of carbonate concretions can be attributed to the same phenomenon, their possible diagenetic origin can not be neglected. nevertheless, the fact that yellowish brown mottled clayey-silt undoubtedly developed above the water table indirectly implies that it was sub­ jected to soil forming processes. unit [[ probably developed in a shallow, oxic lacus­ trine to marshy environment with periodic fluvial influ­ ence during the lower and middle parts of the unit. in the upper part of the unit, loess conn·ibuted to the local material. as a result of increased sediment supply, or reduced subsidence, or changing climate, the sedimen­ tary basin became a seasonally dry marsh (tluctuating water table and gleying phenomena) which successively dried up (yellowish -brown mottled well drained appear­ ance). in the drill core bp-4, the greenish-grey sandy clayey silt with sporadic pebbles, irregularly distributed calcite, possible siderite concretions, and lack of yel­ lowish-brown mottled appecmlllce can be atttibuted to processes of burial diagenesis. rett alack (1990) states that a serious complication for the interpretation of seasonality in swamp soils is the tendency of such lowland regions to be slowly subsiding sedimentary bas ins. as a result, a seasonally dry swamp may sub­ side below the water table to become a permanently waterlogged soil. tn addition, soil can be strongly reduced upon burial and subsidence into a biologically active water table. while in drill core bp-i, the boundary of unit til with the underlying unit is emphasized by a marked change in colour, in the drill core bp-4, the contact is sh~up and marked by an abrupt change in granulometric composition and slight change in colour. in drill core bp-l, the lower pmt of the uni t is coill­ posed of greenish-grey sandy-clayey silt to clayey-silt with sporadic plant remains. the grain size parameters (fig . 12) of the greenish-grey sequence suggest a loes­ soid origin. the lower part of the unit in the drill core bpa is composed of an ungraded , sand dominated mix­ ture of gravel, sand, silt and clay. such a latera.! differ­ ence can possibly be attributed to the position in the sedimentary basin, probably related to the proximity of land or a tluvial inflow in the sediments of unit iii (drill core bpa). the greenish-grey to grey colour, accompanied by plant remains (e.g. bpi) and p)1·itized wood fragments (e.g. bpa) together with a lack of carbonates, strong ly suggest that the sediment was developed in a reduc ing, acidic, probably marshy environment. the presence of ostracodes and remains of lifhoglyplllls in the grey sandy silt above the marshy, greenish-grey clayey-silt, indicates a fresh water inflow, which resulted in the less acidic conditions necessmy for the preservation of cal­ cite and dolomite (in drill core pp-2) , geologia croatica -16/1 above the fossiliferous grey sandy-silt is a yellow­ ish-grey to grey si lt y -sand, over la in by yellowish­ brown mott led silty-sand pa laeosol. furthermore, the upper part of the unit is characterized by the presence of greenish-grey clayey-sill in the drill core bp-4, and yellowish-brown clayey-silt in the drill core pp-2, both with the abundant cartxm<lte concretions. observed lat­ eral changes, mainly related to colour and the pres­ ence/absence of carbonate concretions can be attributed to a f1ucculating water table , both, during pal:leosol formation and after burial. unit tv is composed of s~uldy gravels. we interpret this unit as a tluvial deposit. no distinctive conclusion on source material can be drawn from clay mineral assemblages (figs. 13 and 14). in clastic sediments of pleistocene age, situated along the southern slopes of mt. medvednica, the main clay minerals besides illite are vermiculite and smectite (slovenec & siffar, 1991). kaolinite is observed as well. while chlorites in low-metamorphic rocks of mt. medvednica were the minerals , out of which ver­ miculite and smectite were form ed during the weather­ ing processes, the problem of the origin of kaolinite remains to be resolved. clay minerals in rnost clastic lakes are detrital and reflect the composition of the source rocks and there is no exclusive phylis suite (weaver, 1989). cham­ ley (1989) stated that a general correlation ex ists between the mineral composition of most freshwater lakes and the average clay mineralogy of rocks and soils in the surrounding drainage basins. the use of clay minerals in pa laeosol investigations, with a view to a cl imate reconstruction, assumes that soils form in equilibrium with the climate. if such soils are subjected to the action of erosion, are transported and deposited in a sedimentmy basin (e.g. lake) , the reworked sediments will bear traces of th e mineral composition which actually expresses climate related weathering patterns. for example, kaol inite from the paleosol si tuated at the top of unit i probably formed by the action of soil forming processes, during a warm , moist interglacial. in well drained conditions, kaoli nite is a stable mineral phase. during that period, kaolinite ~l'i a secondary min­ eral certainly developed on remaining continental sur­ faces . in subsequent periods , neofofmed soils were exposed to the action of erosion processes and undoubt­ edly contributed to the composition of younger sedi­ ments . using this mechanism , a presence of kaolinite in the lower parts of units ii and i ii cou ld possibly be explained. the fact that clay minera ls have an important role in these kind of investigations is obvious ly importa nt. future investigations of the quaternary sediments should include investigation of the c lay mineral assem­ blages in related sediments, palaeosols and potential source rocks, respectively. in order to evaluate the role of tec tonic events on the development of the recognized units, the fo llowing velie & dum: altl~m:ltillg l:lcll~trille-ylrsh ... illust be stressed. the morphology of the base surfaces of units ii, iii and iv are mutually different (figs. 8, 9 and 10). in ascending order, they are more simple in appearance. when overlapped, maps in general show neither coincidence between uplifted nor depressed p;u·ts of the study area. this is, aillong others, a conse~ qucnce of neotectonic liiovelllents. the area studied is situated at the mutual edge of two structures. west of precko, an uplifted structure, which was active during the middle and upper pliocene and quaternary was recognized, while due e~l<;t, an inverse structure which subsided during the pliocene and quaternary was observed (vellc, 1980). local processes of tectonic uplift and subsidence were only partly compensated by sedimentation and denudation, respectively, which resulted in wnrping of the ba"le suitaces. 6.2. chronostratigraphic relationships lndex fossils were not discovered and radiometric age determinations and paleomagnetic conelation were not performed, which has resulted in the problematic chronostratigraphic affiliation of the units recognized. by placing all of the relevant data into a generally accepted paleoclimatic framework of the quaternary (markov, 1970; segota, 1966, 19(7), the follow­ ing chronostratigraphic characterization is supposed. it has to be ~tresscd, that during the investigation of strati­ graphic relationships we used the terminology for glacial and interglacial sequences of the alpe regions regardless the serious relllmks concerning their scientif­ ic justifiability. namely, the authors on papers deajing with the quaternary in croatia exclusively used the cla .~ificatioll mentioned. in order to correlate our results with reslj1t~ of adjacent areas, we used the same tenni­ nology. an identification according to the chronostrati­ graphic scale for europe was performed after i-iar­ land et al. (1990), especially in division on the lower (early) , middle and upper (lote) pleistocene, and after nilsson (1983). the oldest unit is lower pleistocene in age. since of dominant loess origin, it is considered to have fonned during the menapian (gunz). this is also cor­ roborated by the position of the conditional marker horizon q', which wa-; defined over a wider area of the sa va depression (hernitz et ai., 1980) on the basis of logging, performed on cores from about a hundred loca­ tions around zagreb, sisak and mt. moslavacka gora. this miu"ker separates the lower pleistocene from the middle pleistocene, upper pleistocene and holocene sediments, as documented by urumovic et al. (1976). above the q' marker, the "unconsolidated material" of hernitz et al. (l981) is situated, which is, compared to the underlying, fine-grained, semi-lithi­ fied, impermeable sediments, mainly composed of per­ meable strata. on the basis of described ch;'u'(lcteristics, it is possible to recognize the q' marker on the well-log 83 traces which are shown on figs. g and 7. isopach map (hernitz et ai., 1980, fig. ii), showed that infened thicknesses between the q' mmker and the ground sur~ face, in the area of precko \vere lower than 50 ill. our results indicate that the maximum depth of the q' marker is 40 rn (well bp-l, fig. 7) unit ii is middle pleistocene in age. contact with the underlying unit is sharp. in the lower part, unit ii is composed of grey, poorly sorted gravels and sands, deposited by running water entering a shallow lake or a marsh. we consider the lake formation to be related to the holstein interglacial cmindel/riss), during which a moist, warm climate prevailed. the granulometric and bulk composition gradually changes upwards with increasing silts and clays, possibly indicating, that the transport mechanism also changes, probably with the incoming glacial, possibly saalian criss). during the mentioned glacial at least two w::u"ming phases occured and therefore the lacustrine-marsh type sedimentation was probably maintained until the very end of saalian. the increased loess contribution, accompanied by mmked cooling and dryness during the last third of the saalian glacial, resulted in long lasting aridity, correlation with the results obtained in the vicinity of podsused by velic & saffle (1991), also suggests the middle pleistocene age of ullit ii, as pebble litholo­ gies at both localities ;ue almost identical; sandstone and qualtz/quartzite pebbles being predominant. we consider unit ilf to be of upper pleistocene age, (predominantly lower to middle weichselian). panicle size analyses partly indicate a loess origin of the materi­ al. a marsh type environment is also documented. marshes were possibly formed during the upper prut of the moist and warrh eemian interglacial (riss/wunn). compared to the holstein (mindel/riss) interglacia! , this was characterized by decreased humidity. frequent lateral changes of lithological composition occur. fluviatile gravels and sands, found in a small numbel of localities indicate the proximity of a coast line. in the upper part of unit lit varve were recognized in the field, as alternating millimetre thick, light-coloured, fine-grained sands and dark grey to black silts. they are a typical product of glacial conditions. since the maxi­ mum quaternary cooling began during the second half of the weichselian (wunn), these sediments are compa­ rable with the climatic conditions. it has been previously stated, that pyroxene was not found in the heavy mineral fraction of units i, ii and ill. this is in agreement with studies by raffaelli & mutic (1982), who concluded, that the lack of pyroxenes is a typical characteristic of the upper pliocene-pleistocene sediments, compared to the sava sediments of holocene age. unit iv is holocene in age and of fluviatile origin. well rounded pebbles of, predominantly carbonate composition, as well as the degree of sorting, coite~ spond to the results, obtained from exploration wells situated slightly west of the study area (velic & saffic, 1991). 84 im ( i! bp1 1 2 ,-, g b, g g b,g , , g g ~gr c. -()r ggr g-gr v-b glfy -8 g-gr v-g v g g . . g ........ g --, ~b'g g g g g g , y " ,, y" y -" y-" c."yr ,, ,, y-r g 3 4 5 6 /"/. ) 0 20 " 60 , , , , , -= m ,o ~ ... !l <> _ o r 0 ... n .. ~ ? : ilg ij c,)rr~ la l ion of rc:;ults of fidd anu [:lbumtury investigations, wdj rpi . s1. 13 knrdacija rc1.ll lt :lla l ~r.:nski h i labljr:llorijskih islrai.ivanja , bu;:;oiina 01'-1. (wi "i.) oj 100 * * * 111 oo0 ~o l 12 0 13[8 ~ 210 1.4 ~ ooe o ~ ~ 7 b { "/01 0 '" " '" oj 100 ~.ioiaijjij.ud~·1 , , , , , , , , , , r-----i * ftt-m-f1!!t/wi * • • • 111111111111111111 *... .. * • • * • • 9 iv iii iii ii ii 22~ 23~ 2 '4~ 25[ggr l 2,6b 2,7 [ggy-bi 2,a [ y t b i y r 29~ 2,10 [gli'y-rj 31 0 3,2 0 330 3.40 3,5 [, "i 36[ , i 3'7@j 3,a~ 39[ @ i 41 [c::j1 42[1 ? 'i 5,1 5,20 5,3 ( ( 5,4 d 61 0 6,2 63 64 6,5 6,6 0 67 0 6,ad 7 1 7,2. 73 d al~ 8,2b 8,3 b 8.40 8,5 0 8,60 8.7b 88 [2] 89 8 8,,00 8''' 0 8,,20 8 , '3~ 91~ 92qid 93 0 94[jj ,0" 0 l.a:gcnj for figs. \3 and 14 . i..cgcmb j;;j slik.:! l ?o i 14 veil'; &. 1)11n!: allenl;\lllig l':ii.:\j~lrlll<,· '\1:! r..h .. 1m ' bp-4 1 2 , .. b-o o y'g , y. , o o o , o g-gr o , o o o g y-gty-r y-r yr 3 <> = 0 <> 0 .. .. .. 4 = n '? ' , . , n : ? ~ 5 fig. 14 corrl!luiutl nf r~':.i1 i( ~ of fidj ano laboratory invl!sligaliol1s, wdl i3p-4 . 6 si i'; k{jr.:i;h:ija r~ndtala kn.:n:-kih j laboratorijskih is(r;jzivanja, bll ~v(j!la i3p-4. 1. lithology: 1.1 ):r;lvd: 1.2 =~;mj: 1.3=silt: 1.:i=1:1:iy 7 8 * 1111111111111 * •• • * ... *. * * • *. • * ' 1 • • • • 85 9 iv iii iii ii ii 2, colour: 2.1 ,l:fi')': 2.2_ briglll grt,y; 2.3=brownish gn:y: 2.:1 =ycllowish !:in:)'; 2.5=grcyi~h green; 2j'=yd lowish brown: 2.7=grl'y 3110.1 ),l'ilowi"h brown: :u~ ydow i~h 8f{')' :\jld ),"liowish rc<.t: 2.9 ,=yc ll owi.~h n:j; 2.io=gre)" :md ),ellowistl red 3. p.:il:l\·oulnlo)o:il':11 ,~)111bo[s :md soil· fonning/after lxlri:ll ft::j.ll1res: 3.1 =11iohl.~c3 fr'lglllcl!t~; ].2=oslr:lcol\s: 3.3 rhi zocolll:rctions: 3.4"'i'i:li\t rr:lg\\wllt~: j.5 -= wood fr.18r1lcllts: ]j;-=mnuks: 3.7=pyrite: 3.8=c3kt:rolj~ i:o[](;n:liolls: 3.9=limonitizl'j 1'")<.:k fr:1811ll:1l1 4. lolh's wilh t"t-:iiui"\.'s "hi..:h jndicile pos..<ible soil fomling pro<,xsses: 4.i=p:\l;h'n~nl; 4,2 =1li\ddcnl\ilh~d lower ooiu1j.:iry of:l l'al:h~osol 5. gr.lin si1e di~trilxltion: s.i::::gr:wd; 5.2=s:lild: 5.3-,silt: 5.4 -1:13), ii. gr:.lvcl<.:oml'n~iti()i\ (gr;l/mlc~ :lild pi;bbks): 6.1 =limt:stom:.~: 1l.2=dolosiollcs; 6.3 sallds !on'l~; lia"'qllartl.i!es: {'.5=.:x!nlsivc rock.~ and tuff: 6.6=coliglotlll:r:i!c~ 311,[ br"cci:ls: {,.7=chcrt: 6.8",othcr rocks 7. sdcl'lcd hc~vy l\linerj.t~ ralios: 7.1 =gamd: 7.2=epi,toic: 7.j =l.in:olll tollnn:tlille 8. mii icr:ti<)gi~·~i..:<)mposilion of d~y :md silt rich mat{:n3is: 8.1 =,iolnmil": 8.2=ral<.:i le; 8.3= unijclllifi.-d ":3rooil:lle miner-ii (pmsibly sidcrite): 8.'1-:tiuat1z: 8.5=pb giocl:lsc: 8.f, ..., fdd.'p:tr: 8.7=go<;lhilc: s.8 mica: 8.9=chlorit.·: 8.io-mllectitc: s.ii =mi:lt:d-byl:r cby ihiner:lls; s.12=k.:lolinit.:: s.13=i.klllificd milwml..:on~tiluent 9.ldmtified iintls: 9.i .:.unii iv: 9.2 _ul\it iii: 9.3 =unii 1l : 9.« ::::unit i 10.1 =i-'ositillll 01':1 s:lillple. i. ulolo;kl s:i~i~v: 1.i=sljull:t.k; 1.2=pijt:s.:lk: i.j=si1t: 1.4::::glina 2. n oj:1 n~~i~g.,: 2.1=~ivo: 2.2:::svij<'llosivo: 1.3~mcje'<ivo: 2.4=i\\':bsto~ivo; 2.5 sivk:ll>toze1cno: 2.(, ·zui·kastosrnede: 2.7 sivo i 1.\jck:i.~lo.~mt:tk: 2.8=1.w;bslosi vo i lu":k.1sto<.:rv .. uo: 2.9=f.ti";k:!slocrvetlo: 2.io=sivo i zutk:!stocrveno 3. p3lconotolo~ke owake i i'cuogel\dske/dij:lgcoct.:,ke poj~ve: 3.1' fr:lgnh:llti ij\j~ulr;j iilckll.h,:a: 3.2=ostr;lkoji: 3 . .i e rizokonkn:cijl:: j.<1=biljno tnmj,': 3.5 =osllci drvet:!: 3.6 .... bn:: j.7=pirit: 3.8""brlx)[j3ine konkrecijc: j.9=fr:j/91h:ll li lirnnnilizir:luih stijen:l 4. zone ~ poj.1v:l!l1~ kl)jc llknuju n:! ptoc,~~e stv:lr.l1lja tb: 4,i=p:l lcotlo; 4.2 p~kl)llo txzlilvrdcnc d(jllje gr:mice 5. grjllulnlllclrij~ki ~;l~tav: 5.1 =sljunak: 5.2=pijes~k : 5.3=si it: 5.4=glil1:t 6. i\'trngr:lf~ki s:ist:1v v:llutil:3: 6.1 =v"[lilcrl:jc: 6 .2=d(jlor!lil; 6.3 =p jc~ccnj:\k; 6.4 k v:trl:it; 6.5=cfllzivi j tllf: 6.6=kof18jolllerjti i brcce; 6.7=ccr'l: ii. s o~1:\i.: stijt:ne 7. o.ll\1)s iz:il)r.11i ih h'skih lili lierala: 7.1 :gr:ln3t: 7.2=epidol; 7.3 =<.:i rkon + tunllal ill 8. min<'f:t ini ~':i~tw gli!1.~ i siltova 8. j=dololl1 il; 8.2=blcit; 8.3 ncd<:finir:h1i brbollat (vjcrojatno sidt:ril): s.4=kv:lre: 8.5=p l a 8i()kla~; 8.6=fddsp:,i; r.7=gctit: 8.8"'"tinjci: 8.9 kiorit: s.io sll1ektit: 8.ii =mijdilno·slojni !l1 iner3 ii glilt3; 8.12=k:\ol in it; 8.13=ident ificir:mi miner;)l 9. iblluc<'ll<' j(:dinicc: 9.i =jcdinic:j.1 v: 9.2 ::jedinica llf: 9.3=jcjinicall; q .... ·.::jcdini<.::t r lo.i =pnlobj lizork:l. 86 overlying palaeosols indicate phases of subaerial exposure. units ii , rn and iv overlie palaeosols, indi ­ cating that the uppermost pmls of units i, ii and iii were exposed to the act ion of pedogenesis. three palaeosols occur in a 60 in thick interval of sediments. while the oldest palaeosol displays the greatest thick­ ness (in some cores more than 10 meters), the youngest is the thinnest , ranging in thickness from 0.1 to 0.7 in. their formation is closely related with palaeoclimatic conditions implying that warm periods of specific humidity and duration are required. since the differ­ ences among interglacial mean annual temperatures are relatively small (emiuani & shackleton, 1974), the differences in pajaeosoi thickness were undoubtedly intluenced by the duration of sediment exposure to soil fomling processes. nevertheless, it has to be stated that some authors assume that strongly developed pre­ wurm paleosols fanned under long intervals with cli­ mate similar to the present (e.g. boardman, 1985), whi le others (e.g. karlstrom, 1991) find that the mean temperature and precipit.:1.tion during formation of the paleosols was at least 6-8°c wanner and 40 clll higher than present. during approximately 200,000 years of the cromerian and elsterian, almost the com­ plete drilled interval of unit i was subjected to the action of soil forming processes. in the eernian inter­ glacial , which lasted slightly less than 100,000 years, up to 2.6 m of the uppermost p'u1 of unit ii was affect­ ed by pedogenesis. a palaeosol, approximately 0.5 m thick, formed in the top palt of unit iii , during the peri­ od of 4000 to 6000 yem's in late weichselian and, possi­ bly, early holocene. 7. conclusions on the basis of performed field and laboratory investigations accompanied by natw-al-gamma radioac­ tivity measurements four units are recognized (figs. 6, 7,11,12,13 and 14). unit i is predominantly composed of yellowish-red, yellowish-orange and yellowish­ brown, poorly-moderately cemented, dense, clayey­ silts/silty-clays. sporadic lenses and interbeds of grav­ elly-sands, up to a few dm thick also occur. highly variable coefficients of sorting, compared to the aver­ age values (fig. 12) possibly indicate that loess, mixed with local materials (ioessoid) has contributed to sedi­ ment composition. the almost complete absence of gar­ net may be a consequence of aeolian transport. unit j is lower pleistocene in age and is considered to have formed during the menapian. this is substantiated by the conelation between the conditional marker horizon q and the unconformity which separates unit j from unit it. tn addition, earlier investigations showed that inferred thicknesses between the q' marker and the ground surface, in the area of precko were lower than 50 m, while, according to the present study, the maxi­ mum val ue is 40 m. unit ii ranges in thickness from 10.35 to 24.3 m (kologi;] crrntica 46/1 (fig. 3) and is interpreted to be middle pleistocene in age. the unit is relatively uniform in composition: while the lower and middle p~u·t is predominantly cotll­ posed of grey coloured sands, the upper part comprises grey coloured or red to yellowish-brown mottled silt and clay sized material. comse-grained sediments in the lower and middle part of the unit are poorly sorted. the high matrix content indicates that they were r~lpid­ iy deposited in a quier-water environment i.e they were deposited from running water at the point of entry into a shallow lake or a marsh. the lake was formed in a humid climate, during the holstein interglacial. with the incoming glacial, possibly saalian, the granulomet­ ric and bulk composition grad ually changes upvv'ards indicating that the transport mechanism also changes. as the result of increasi ng loess accumulation accoill ­ panied by a marked cooling and dryness, the lake/mm'sh dried out. unit iii is heterogeneous and ranges in thickness frolll 6.15 to 13.2 iii (fig. 4). the unit is characterized by frequent lateral changes of gravels, sands, si lts and clays. \vhile the sands are predominantly grey coloured, the silts and clays are often mottled in yel­ lowish and brownish shades. in the upper part, v;uve are recognized , as alternating, millimetre thick light coloured, fine-grained sands and dmk grey to black sills. while particle size analyses partly indicate a loess origin of the unit, some recognized features suggest that the sediment was accutliulated in a marsh type environment. resumption of a quier and shallow water environment coltesponds with the upper part of the moist ;uld warm eemian interglacial. consequently, we consider unit iii to be upper pleistocene, principally lower to middle weichselian in age. unit lv varies in thickness from 6.6 to 7.7 iii (fig. 5) and is holocene in age. it is composed of pale, yel­ lowish-grey coloured gravels and sands in which lime­ stone cobbles prevail. the upper parts of units i, ii and iii were exposed to the act ion of soil forming processes during ph,llles of subaerial exposure. at least three zones with palaeosol characteristics were recognized. the criteria used to recognize the palaeosols were: (1) different colour compmed to the overlying and underlying material, (2) presence of mottles, (3) presence of concretions and nodules, (4) evidence of weathering of minerals (goethite) and (5) presence of roots and organic matter fragments. these zones are closely related to the observed unit bound;u·ies. while the oldest palaeosol (unit i) displays the greatest thickness (in some cores more then 10m), the youngest paleosol (unit iii) ranges in thickness from 0.1 to 0.7 m. their formation required warm periods of specific humidity and dura­ tion. we consider these periods to be related with the cromerian and elsterian, eemian, and late weichselian and, possibly em'ly holocene respectively. the occurence of both specific sedimentary envi ­ ronments and phases of subaerial exposure was also influenced by tectonic processes. the morphology of velie & dlim: altemating l ..ac\l~trinc· m1.rsh ... the base surfaces of units ll , iii and iv are mutually different (figs. 8, 9 and 10). in ascending order they are more simple in appearance. this is, among others a consequence of neotectonic movements. namely, the tl rea studied is situated at the mutual edge of two struc­ tures which have been active till quaternary. local processes of tectonic uplift and subsidence were only partly compensated for by sedimentation and denuda­ tion respectively. acknowledgments the au thors would like to thank b. lugov ic, d. slovenec and j. tislj:u for allowing them to use the results of their laboratory analyses. thanks al so go to z. blazevic, g. hubeny, z. paladin and b. sladovic, whose understanding, supon and interest enabled the performance of in vestigation works. the precious and patient assistance of b. s\adov ic during field -work is gratefull y acknowledged. 8, references allen, j.r. ( 1971): physical proc esses of sed imentat ion.a ll en and unwin ltd., london, 248 p. boardman, j. ( 1985): comp,uison of soils in mid~ western united states and westem europe with the interglacial record. ~ quo!. res., 23, 62~75 . borc ic , d., capar, a., cakarun, i., kos~ tovic, k. , miletlc, p. & tufekcic, d. (1968) : prilog daljnjern poznavanju aluvija lnog vodonosnog horizonta na sirem podrucju zagreba.­ geo!. vjesnik , 2 1, 303~309. chamley , h. ( 1989): clay sedirnentol ogy. ~ springer verlag, 623 p. crnkovic, b. & bus ic, m. ( 1970): mineralosko~ petrografski sastav ilanosa rij eke save.z bornik radova rud. -geo!.-naftnog fak. sveuc. zagreb u povodu 30 god. rada (l939~ 1969), 133~ 140. ca karun , i., mraz, v., babic, z., mutic, r. , sokac, a. & fran ic, d. (1987): geoloske i hidrogeo!oske specificnosti kv<utmtiog vodonosnog kompleksa pri savske ravnice na dionici granica sr slovenija ~ rugvica. ~ geol. vjesnik, 40, 273~289. em 1uan i, c. & shackleton, n.j. ( 1974): the brunhes epoch: isotopi c paleotemperatures and geocluonology. ~ science, 183, 5 11 ~5 1 4. einsele, g. (1991): sedi mentary basins. evolution, facies and sediment budget.~ spri nger verlag, 628 p. harland, w.b .. armstrong , rl, cox, a.v., cra ig , l.e., sm ith , a.g. & sm ith , d.g . 87 (i990): a geologic tim e sc al e.~ ca mbrid ge university press, 263p. hernitz, z., kovacev ic, s., veuc, 1.. zeljko, b. & u rll , m. (l981 ): primjer komp le ksnih geolosko-geofizi ckih islrazivanja kval1arnih naslaga u okol ici prev lake. ~ geol. vjesnik , 33, i j ~34. hern itz, z., velic. 1., kranjec, v. & najden~ ovsk i, j. (1980): prikaz diferencijaln ih i maloapli ~ tudnih struktura s primjerima iz sav ske poroline (p"nonsk i bazen). ~ nafta, zagreb, 7~8, 399~409. gorjanovic~kramb erge r , d. ( 1908): geologijska prijegledna kart a kraljev ine hrvalske­ siavonije. tumac geologijskoj karti zagreb (zona 22, col. x lll ) . ~ nak !. kra lj . zemalj. v lade, odjel ullutar. pos!ove , zagreb, 76 str. karlstroom, e.t. ( 199 1) : pal eoc lim atic signifi cance of late ce nozoic paleosoils east of waterto n-glacier parks, a lberta and montana. ­ paleogeography, palaeoclimatology, palaeoecology, 85, 7 1 ~ 1 00. kraus. m.j. ( 1987): int ergrat ion of channe l and tloodplain suites. ii vertical relations of allu vial pal eosoiis.~ jour. sed. petrol., 57, 602~612. kukal. z. (197 1): geology of recent sed iments. ~ academic press, london , new york, 490 p. leck ie, d., fox , c. & tarnoca i, c. (1989): mu lti p le paleoso il s of the la te albian boulder creek format ion, brit ish columbia , ca nada. ­ sedimentology, 36, 307~323. markov, k.k. ( 1970): le froid e ie periglacime du pleistocene.acta geographica lodzensia, 24, 33734 1. miletic, p. & borcic, d. ( 1967): prilog poznavan ~ ju podzemnih voda na podrucju zagreba .geo!. vjesnik, 20, 285~29 1. morison, r.b. (1978): q uatemary soil stratigraphy ~ concepts, methods and prob l ems.~ in: mohaney, w.c. (ed.) : quaternary so il s. geo abstracts, norwich, 77-108. nihlen, t. & solyom, z. (1986): dust storms and eol ian deposits in th e med iterranean area. ­ geologiska fbreningens i stockholm f6rhandlingar, i 08, 235~242 . nilsson, t. (1983): the pleistocene.~ ferdinand enke verlag, stuttgart , 65 1 p. nov ins ka, n., miletic , p. , borcic, d. & tufekc ic, d. ( 1967): pri log poznavanju aluvi ~ jalnog vodonosnog hori zonta na uzem podrucju zagreba.~ geol. vjesn ik , 20, 293~30 i. pye , k. (i987): ae oli an dust and dust depos i ts. ~ academic press, new york, london, 334 p. raffa elu , p. & mutic , r. ( 1982): mogucnost s. razdvajanja asocijac ija teskih minera la primjenoll1 fakt orske anali ze.x jubil arni kongres geo loga ju goslav ije. bud va . zbornik radova. 1.495-508. retall ac k. g.j. ( 1990) : so il s of th e past. an int roducti on to paleopedo logy. unwin h yman, boston. 520 p. rotsc hy. f .. vergnaud-grazz ini. c. . bel­ ba ic he. g. & c ham le y. h. ( 1972): e tu de paleoclirnatologique d' line carotte pselevee sur un dome de la pl ain e abyss al e li g uj'e ("stru cture a i in<h "). palaeogeograph y, palaeoc l imatology, palaeoecology. ii . 125 -145. slovenec. d. & si ftar , d. (1 99 1): vennikulit i smekl it 1i klaslicn im sedimenlima juznih ol>ronaka medvednice.geol. vjesnik , 44, 12 1127. segota. t. (1966): quaternary tempera ture changes in central europe. erdkun de, archi v fiji' wis­ senschaft liche geographie, bon n. 20, 11 0-11 8. segota. t. ( 1967): paleotemperature changes in the upper and m iddle pleistocene. eiszeilalt er lind gegenwart , oehringen, 18, 127147. sikic. k. & basch. o. (1975): geoloska zbivanja od paleozoika do kva rtara ii zapad nom dij e lu z<-1grebacke reg ije.ii god. zmmstveni skup sekcije za primjcnu geo!. , geoti z., geokem. znanstv. savjeta za naftu jazu , zagreb, al5, 69-86. s iki c. k .. basc h. o. & s imun ic. an. ( 1979): osnov lla geoloska karta sfrj i: 100.000. tuma" za li st zagreb, l 38 -80. in s!. geo l. istraz. zagreb (1972), savezni geo!. zavod, beograd , 8 1 p. s im un ic, an. & basc h, o. ( 1975): strati g rafija kvartcunih sedilllenata zagrebackog pos:lv lja.geol . vjesnik.28. 153im. s imun ic. a i. , novosel-s ko ri c. s. & pilj urovi c, lj. ( 1988): lito loska kore lat' ija i krollostrati grafsko razgmnicav;l nje kv(lj'larnih n:tsla­ ga na lokalitetu prev laka jugoistocno ad zagreija.­ geol. vjesnik , 4 1. 167 -179. uru movtc, k. , hern itz, z., simon, 1. & veli c. j. ( 1976): 0 propusnom mediju kvartarn ih ie gorn­ joi srednjopliocenskih naslaga sjeverne hrv<l tske.­ zbornik radova 4. jugos l. simp. 0 hidrogeo l. i inz. geo l. . skopje , i, 395-4 10. veli e, j. ( 1980) : geo loska gral1a zapadnog dijela sav ske depres ije. phd t hes is. ull i ve rsity of zagreb. 137 p. velie, j. & safti c, b. (199 1): subsu rface spread ing and fac ies char"lcteristics of midd le ple istocene deposits betwee n zapresic and sarn obor.geo!. vjesnik. 44. m -r2. weaver , c.e. ( 1989): c la y. muds , a ll d sha les .­ elsev ier, 8 19 p. veli,,; & dum : al1<:m~lillg lacllslrillc m:h~h ... izmjena jezersko-mocvarne sedimentacije i kopnenih faza tijekom kvartara na lokaciji i'recko (zagreb) j.velie i g. durn na lokacij i precko povrsine od 6 ha (s l. i ) proueene su talozine u prvih 60 iii dubine. izradeno je sedam bllsoti na; cet iri na lijevoj i tri na desnoj obaji save (s1. 2) . izvuceno j e ukupno 390 iii jezgre. one su na terenu determinirane te je prikupljeno i vise desel.aka uzoraka za laboratorijskll i kabinetsku obradu . u busotinama su obav ljena geofizicka snimanja prirodne i izazvane radioaktivnosti. tijekom st udiranja stratigrafskill odnosa djelom ice su koristeni nazi vi gl8cijalnih i interglacijalnih sekven­ cija za podrucje alpa bez obzira na ozbiljne primjedbe gledc njihove znanstvene utcmcljc!losti. naime, au tori kvartaroloskih radova 0 terenirna hrvatske rabili su iskljucivo spomenutll klasifik(lciju pa smo korelirajllci !lase s rezultatima za sllsjedna pocjrucja i illi illorali tako postupiti. jdentifikacija s kronostraligrafskom skalom za europu obavljena je prema harland el al. (1990) n(u"ocito 1i podjeli na donji (rani), srecinj i i gornji (kasni) pleisloce ll , ie prema nrlsson (1983). na temelju sv ih terenskih i laboratorijskih poclata­ ka te prosjec ne prirodne gama-radijacije (s1. 6, 7, [i, 12, 13 i 14) razlucene su cet iri jedillice. leciillica t izgradena je pretezito od poluvezanih, gustih glinovitih silt ov a/s iltoznih glina karakteristicne zutonarancaste (crvcne) iii zljtosmede boje. sporad icno sli prisulne ieee slj unkovitih pijesaka debljine nekoliko decimelara. m,llo povisene vrijeclnosti koeficijenta sortiranja u oclnosu il<l srednje vrijednos li (s1. 12) ukazuju cia se vjerojatllo racli 0 icsu pornijesanorn s lokalnim materi­ jalolll (lesoid). goiovo potpuna od sutnost granata illoguca je posljedica eo 1skog transporta ce stica. spomenuti krupnozrnasti klastiti ukazuju pak i nn donos vodama tekuciclllna, najcesce blljicama lj plitkll slatkovodnu sredi nu. l edinica je donjopleistocenske stllrost i. pretpostavlj~lmo cia je nastala tijekom menapi­ ;lna (glinz). u prilog takvog tllrnacenja lib raja se i podu ­ daranje kroville ove jeclinice s llvjetnim reperom q' kao i ranijim islr:-lzivanj irna pretpostavljene debljine stijene od repenl q' clo povrsine terena manje od 50 m, ovdje konkretno oclrc(1eno 40 ill. jedinica ii debljine 10,35 do 24,3 iii (s l. 3) inlerpre­ tir:ma kao srednjeplei stocenska, j ednolicnog je sastava: ii donjclll i srednjern su dijelu uglavnolll pijesci sive ijoje, a u gornjem sve vise irna si ltova i glina, sivih iii "sarenih" s rnrijailla crvene do zlitonarancaste boje. krupnozrnasl i kjastiti donjega i sreclnjega dijela lose sll sortirani. visoki ucljel glinovito-siltnog matriksa u njim<l ukazuje da su tajozeni u uvjetirna brze sedi ­ mentacije u vodenoj sreclini niske energ ije, tj. da su nastali akumulacijolll iz voda tekucica prigodom lltoka u jezero iii moevarll. lezero je fonn irano u mladem 1101steinu (m illclel/r iss interglacija l) zahvaljujuci prven ~ stve no humidnoj klimi. s nastupanj e glac ijala saal e (riss) postupno se mijenjao sas ta v, vel icina i nacin donosa cestica, tj. sve je izrazenija i akllillulacija lesa, 5to je uz zahladenje i susll prouzrocilo presusivanje jez­ era/moevare. ledinica 111 karakteristicna je po heterogenom sas­ tavu i varijacijama deblj inc od 6.15 do 13,2 iii (s1. 4). radi se 0 cestirn boenim izmjenarna sljullaka, pijesaka, siltova i glina. pijesci su iiglavnolll sivi , a siltovi i gline testo mrljasti u nijansama zute i smet1e boje. u gornjem sll dijelu uocene varve: milimetarske izl11jene svijetlih silllozrnastih pijesaka i tamnosivih do crnih silt ova. prema vejicini cestica ova je jedinica clominantno lesnog podrijella s obiljeij ima geneze ii 1l10cvarnoj sre­ ciilli 5to zll;lci i unosa detritusa voclenirn iransportoill. obnavljanje mime, plitke voclene sredine u korelaciji.ie s vlazn im i toplim interglacijaloll1 eern (riss/\viirrn) i to njegovirn mladim dijelolll, dok je seclimentacija razrna­ trane jedinice gornjopleistocenske, pretezno starije do sreclnjoweichselske (wlinn) st;u·osti . debljina jedinice tv krece sc oct 0,6 do 7.7 m (s l. 5). radi se 0 holocensk01l1 sljunku i pijesku svijct le zllckaslosive boje, stancjarcinog petrografskog sastava savskih nanosa kcxl kojih su dominantne valutice vap­ nenaca. vrsni clijelovi talozina i, ii i iii jedinice bili su izlozeni procesirna pedogeneze. ustanovljena sll barem hi nivoa sa znacajkarna paleotala. to sll zli to ­ narancasta-crvena-smeda boja nasjaga, prisutnost mrlja iii sara , konkrecija , nodula, korijenja te illinerala trosenja (get it). odnosni sll nivoi usko povezani s grani ­ cam a medll jedinicama. razlieito su izrazeni. obuhvacajll od preko 10 m (jedi nica t) do 0,1 m uedinica ill ). za njihovo je stvaranje bila potrebna lopla klima odret1ene vlainosti i trajanja, cem u odgo­ varajll intervali od cromera clo holsteina, zatirn raniji eern i naposljetkll kasni weichsel s eventual no starij im holocenotll. na genetski tip naslaga j pojavu kopnenih faza utje­ cali su lakoder i tektonski procesi. oblici podinsk ih ploha jedinica ii, iii i iv (sl. 8,9 i 10) uglavno se medllsobno ne podlldaraju , a icluci prema mladima razlucene jedince se rasprostiru llilutar sve manjih visinskih intervala. to je posljedica razlicito izrazenih 10ka lnih spllstanja i izdizanja u rubnirn zonam<l nasljedne (na zapaclu od preckog) i inversne (na istoku) strukture, aktivnih do u kvart~u· . tektonski pokreti su oci to sarn o djelomice kompenzirani seclimentac ij om, 90 odnosno denudacijolll. i na kraju, ali ne i manje vazno, jedna pripomena. kako bi se izbj egje nedoumice, a omoguc ile strati ­ grafsk e usporedbe s europskim i sv j etsk im post ignucim3, ubuduce sv akako tre ba pred vidjeti i obavljat i rad iometrijske analize (osim testa prilllijenji ­ va nu rad iok arbonsku metodu i mj erenja na bazi dugozivucih radionukleida) uzoraka kv31tamih ta loiina s terena hrvatske kao i paleomagnetne korelacije. to je jedini nac in da se dode do kriterija za valjanu i opeepri ­ hvallj ivu kronosu-at igrafsku klasifikaciju _ geqlogia cro.1ti(;:l. 4()!1 autori zah valjuju b. lugov icu, d. siovellec li i 1. ti sljaru sio su dopustili kori stenje nj ihov ih laboratori ­ jskih analiza. vel iku zah va]nost takoder treba izrazi ti z. blai.ev ic, g. hubenyu, z. palacl inu j b. s laciov icu pora­ di razumijevanja, potpore j inte resa bez cega ne bi bilo moguce obavljanje predloienog programi:! istrai ivackih radova. u te renskoj fazi se osobitolll suraclnjom iskazao b. s iadovic, zbog cega mu pripada poseblla zahvala. manuscript received december 12, 1992_ rev ised manuscript accepted march 5, 1993_ geol. croat. 50/1 57·77 7 figs. 6 pis. zag reb 1997 tectonic structure of the island of hvar (southern croatia) stanko marincic key words: kinematics of de formation, tectonic pha­ ses, is land of hvar, croat ia. abstract slrucluml dcfonnalion of ihe island of hvar allows three tangen­ tial tectonic phases to be determined: the laramian (f i), the pyre­ llc,ul ( fo ii) alld the neotectonic phase (f 111 ) . preserved relic s of laramian and pyrenean fold s with intact structura l clements, indi ­ cates tilal the neotectonic orientat ion of st ruclli rcs (e\v) i ~ a conse­ quence of refolding of the older structural fabric, rather than horizon­ [;ii rotatioll. 1. introduction geological development of the is land o r hvar [rom the ncocomian to the eocene-oli gocene (fi g. 1) indi­ cates severa l phases of tec ton ically induccd changes. emersion of apt ian and albian deposits is a regionally widespread example of such tendencies, but the cause is indcterminaled. at the end of the upper cretaceous, during a relatively shon interrupti on in platform car­ bonate deposi tion, more important struc tura l deforma­ tion occurred. these were altributed to the so-cal led laramian tec tonic phase. similarly, the ef fects of the lute tian -oligoeene py renean tangenti al phase, as wcll as the effects of the neogene-quate rnary neotecton ic tangential phase were determined. this nomenclature has been kept because of its his­ torical establi shmcn l in ihe croatian geological litera­ ture. the laramian phase, as the oldest tecton ic defor­ mation, will be referred to as f j, the pyrenean phase as f ii , and the youngest neotectoni c phase as p iti. 2. kinematics of deformatio n and tectonic phases t he 1110s t obvious influences of the tangentia l tec­ ion ic phase on the sedimentary sys tem arc expressed by shorter or longer periods of non-deposition during the e ll1c rs ion phases, or by essen tial changes reco rded in the la rge sedimenta ry systems (e.g. succession from platform carbonates to fly sch to molasse) . such phases institu te of geology, sac hsov a 2, p.o. box 268, iir 10000 zag reb, croat ia kljucnc rijeci: kinematika deformacija, tektonske faze, otok hvar, hrva tska. sazctak na temelj u svojstava struklurn ih dc formacija oloka hvara dcler­ minirane sll tri lange ncijalne lek ions kc i;\zc: laramijska, pircnejska i nco lektonska faza koj c su uvj el rlo olllace ne bo f i, r ii 1 f ill. sacuvani rclikti lararnij skih i pircncjskih bora s inlaklnim stru ktu rnirn ele rnentima, ukazuju da ncotcktonska orijenlacija struklura is lo k­ zapad nije posljedica horizontalnc rotacije vee prcborav<ulja starijeg struklutllog sklopa. were recorded as event s during certain periods of the geological time. however, it is incorrec t to undoubtedly connect each sed iment ary gap with tecton ics, until a clear tectonic cause has been determined. without sllch c lear tec tonic evidence sedim entolog ical changes should be regarded on the levcl o f recogni tion of the characterist ic facies. under the tangen tia l st ress, as a result of the kine­ matic cond itions, the longer axis (b-axi s) o j' the de for­ mati ona l fabri c is o riented normal to the stress. there­ fore, the b-axis of the fo ld , as a product o r optim al deformation, is also ori ented normal to the stress. com­ plete fold geometry , includin g a ll deformati onal se ts (limbs, amplitude, span, index, b-ax is, vergence, joint se ts, e tc.) represents the k inematic record of' a g iven stress oricntation. in practice, under stress o r any orien­ tation , the development or the dcformation will result in stepwise changes, which cou ld be defined as ki nematic stages. from this point or view, kinematic stages reprc­ sen i a genera l paradi gm, which will be explained using the example of the neotectonic st ructural fabric of the island of h va l'. a very important ractor for each geologica l body is it s spatia l position during the geologica l processes. consequent ly, the most important factor fo r its defor­ mational rab ric is its s tructural orientation. both aspects are controlled by geological time. therefore, the prima­ ry deformations direc tl y indicale the orientation of lhe reg iona l s tress during the spec ifi c tangential tec tonic phase. the illciuence of ihe laramiall tec tonic phase (f i) is indi catcd by lhe emersion at the end of the upper creta­ ceous, and sporadic relics of metreto decamet re-scale fo lds. these rolds with a n-s b-axis st rike, and corre­ sponding join! se ts, could have been formed only under 58 i i i i i i i i i i f i 1 ~ i [j cd [j 0 ~ ~ ~ 0 ~ 0 z-== geologia croalic.1 50/1 fig. 1 schematic geological map of the island of hvar. legend: i malmian deposits (simplified); 2 ncocomian platform deposits (dolomites with micrite lenses); 3 barremian-aptian platform carbonates (rhythmic alternaliotl of micrites and bioclastic limestones with dasyc!adaceans); 4 albian-cenomanian plat form carbonalcs (cryptal­ gal laminites and lale-diagenetic dolomites); 5 cenomanian platform carbonates (cryptulgaj limestones containing fossil fish and reptiles, rud­ isl biostromes); 6 turonian-santonian platform carbonates (micriles, oncoidal, crypt algal and rudist limestones); campanian-maastrichtian platform carbonates (homogenous micrites) ; 8 palaeogene flysch; 9 reverse fault; 10 slrike­ slip fault. s1. i pregledna geoloska karla otoka hvara. tumuc: i malmske naslage (pretpostuvljeno); 2 neokomski platformni karbonali (dolomili s lecama mikritnog vapnenca); 3 barcm-aptski platfonnni karbonati (ritmicka izmjena mikrilnih i biok laslicnih vapnenaca s dazikladacejama) ; 4albsko-ccnomanski platformni karbonati (kriptal­ galni vapncnci i kasnodijagcnclski dolomiti); 5 ccllomanski platformni karbonati (kriptalgalni vapnenci s fosilnim ribama i gmazovima, rudistnc biostrome): 6 !uron-santollski pla!forrnni kar­ bona!i (mikritni, onkoidni, kriptalgalni i ruciistni vapnellci); 7 kampan-mastrihtski platformni karbonati (ho111ogcni mikritlli vapncnci): 8 pa le­ ogenski nis; 9 reverzni rasjcd (celo ijuskc); 10rasjed s horizontalnirn krclunjem. marinbc: tectonic stnlct ure of the 1~land of 1-1 var (sou thern croatia) pig. 2 neotectonic compression (f iii) reactivating first generation of hoi joints of the pyrencan phase (f ii ) into tensional joints and axial plane joints. si. 2 ncotektollska komprcsija (f][[ ) reaktivira prvu generaciju hoi pllkotina pi rcncjske faze (fi! ) ii tcnzijske pukotine i pllkotinc os nc ravnine. the influence of the e-w oriented regional stress, i.e . during the laramian tectonic phase. relics of the laramian folds preserved their recog­ ni zable geometries although they were refolded during late r pyrenean and neotectonic phases. they were incorporated in the limbs of the neotectonic folds, changing only the inclination of their b-axis (traces of the axial planes of the laramian folds are parallel to the "a-lineations" in the limbs of the neotectonic folds). under the influence of the pyrenean tangential tec­ tonic phase duri ng the middle eocene, a trough filled with fly sc h was formed within the former carbonate platform (marincic, 1981). this even t marked the commencement of the disintegration of the former mesozoic carbonate platform. syntectonic sedimenta­ tion of the eoce ne-oli gocene flysch deposits was, under the influ ence of the sw-ne oriented pyrenean stress, accompanied by the subduction of the adriatic platform beneath the dinarides. the dinarides were folded , forming the famous structural phenomena, known as "t he dinaric st rike" or " the dinaric struc ­ tures". these structures are characterized by their nw­ se st rike and sw vergence. on the island of hvar, pyrenean folds are only spo­ radically preservcd. due to their origi nally diagonal ori­ entat ion (fig. 2) they were unable to provide st rong resistancc to the neotectonic stress. therefore, the only preserved part s of thc pyrcnean folds are those which were in a favourable position to bccome incorporated into the limbs of thc neotcctonic folds. these pyrenean folds have only changcd the original inclination of their b-axis; they also sporadically preserved their pyrenean sw vergence. the neotectonic stress effici ently accept ­ ed each pyrenean fracture which could have been ineor­ poratcd into its own deformational set. the left sliding joints of the first pyrenean hoi generation joint sets formcd joints of the axial plane, and the right oncs for­ med tensional joints of tile neotectonic fold s (fig. 2). although the re lics of laramian and pyrenean folds are not so frequent as thc predominant neotectonic l 23055 l 25878 sis (til -:~fi fig. 3 synoptic ~-diagram of the isl,uld of hval si. 3 sinopti6ki ~-dijagram otoka hvara. ti f iii 59 folds, their presence is very important (fig. 3). under the influence of the neotectonic stress they have only changed the inclination of thei r b-axis, but they pre­ served the original orientation. therefore, their mutual arrangement is rather we!! preserved (fig. 4). it must be noted that their original st ructural fabric was only refolded during the activity of the neotectonic stress oriented n-s . therefore, it was not hori zo ntally "counter-clockwise rotatcd" around the tectonic c-axis, which has recently become the usual explanation for each occurrence of " the hvar strike" in the dinarides (e.g. aljinovic et ai., 1990). only a rootless nappe could horizontally rotate, and the hvar thrust-sheet or thrust-sheets are definitely not examples of these root­ less structures. some locally observed horizontal rota­ tions along the strike-slip faults (hoi) arc of the outcrop­ scale. even the remarkable sum of the ir differential left movements cannot contribute to the predominance of one direction over the other (i.e. rotation), since it is compensated by movements along the right strike-slip faults. besides, these movements are inc luded into the deformations of the kinematic f-stage (the fourth hol generation), which took place after th e formation of "the hvar strike". finally, at the frontal surfaces of the thrust -sheet s with south vcrgence all tectog lyphs are oriented perpendicularly they are not oblique, neither do they generally indicate any aberra tion from thc north-south direct ion. with the appearance of a new global stress oriented north-south, a new neogene-quaternary neotecton ic tangential phase (f iii) began. intens ified subduction continued, resulting in the di sintegration of the adriatic carbonate platform in several parts (aljinovic ct ai., 1987). at the same tim e in the area of the dinarides structural deformations of east-west strike ("the hvar strike") and south vergence were formed. the specific gcological development and geotecto­ nic position of sw istria and the islands of lastovo and probably vis , indicate that they represent rclics of the adriatic carbonate platform. therefore, the island of 60 geologia croatica 5011 sfi sf iii fig. 4 relics of laramian (f i) and pyrenean (f ii ) folds in limbs of the neotecton ic fold (f iii ) near vrboska. si. 4 rclikli laramijskih (f i) i pircllcjskill ( f ii) bora ii krill! ncotcklollske bore (f iii ); vrboska. hvar represents a considerably protruded part of the great structural complex of the dinaridcs in the vicinity of the neotecton ic subduction zone. consequently, it underwent st ronger contrac tion, whi ch resulted in remarkable defo rmation dur ing the neotectonic tangen­ tial tectonic phase. althou gh the direction of the stress is of primary importance for the determination of the tectonic phase and understanding of the geological developmen t of a certain area, it is not so substantial from the kinematic point of view. the idea l kinematic sequence of defor­ malion is iden tical under any stress orientation. there­ fore, the neotectonic deformation of the island of hvar cou ld be treated as a gene ral example. kinematic changes are designated as six stages of kinematic devel­ opment: a, e, c, d, e and f (fig. 5). they are defined on the criter ia of the succes sive appearance of the important tangential deformational sets. the first reaction to compress ion is expressed by a tension parallel to the pl ane of the greates t and the inte rmediate princi pal s tress ( 0"1 0"2)' resulting in the opening of tensional gaping joints of the a-stage. these joint s arc small (centimetre to decimetre scal e), and usually they do not cut the entire thickness of a bed. they arc vely expressive due to their feather-like shape filled with white sparitic calcite. they are present only in the parts of the 0" 1 0"2 plane with the minimal diffe r­ ence be tween resistance and tangential pressure (in li mestones approximately 38° towards the direction of the main stress). during stage b the hoi zone was torn , with charac­ teristic sliding along the conjugated hoi joint sets (the first hoi generation). joints are of the cen time ter to metre scale, usua lly cutting through the entire bcd, but they do not disturb other beds, since they terminate at the interbed djsconlinuity. their dimensions are con­ trolled by the thickness of the bed, and, therefore, they cannot evolve into faults. commonly they arc charac­ terised by small-scale left or right movements with small teetoglyphs parallel to the bedding. these small· scale movements also interrupt tensional joints of the a stage, which preceded them. u nfortunately, this desc ribed succession of events is often misinterpreted; as tensional joints are interpreted as bei ng of secondary origin (as a consequence of moving along the sliding holjoints). the a and b stages represent a period of compensa­ tion of lhe main stress on the level of a single bed. the fig. 5 kincmatic stages of deformation development in the exmnple o f neotec ­ tonic compressio n. si. 5 kinematski stadiji raz­ voja deformacija na prim­ jeru neotcktonske kompre­ sije (f iii), marincic: tecton ic slnlcture of the island or ]-]\'3t (southern cro;llia) .. :0c:.~'. r ig. 6 lrllcgration of thrust-sheets into a kinematicall y morc res i.~ tant larger thrust-shee t. $ 1. 6 i ntegrir~l!ljc ijusaka ii k incmatski otporniju vecu tj usku. continu atio n of stress leads to the substitut ion or the already ex hausled smail-scale resistance wit h a group o f beds. from thi s stage on, the res isting complex is striving fo r homogenization, which in th is way leads to the large-sca le deformation s. durin g the res istance to the material di sintegration , a homogeneous group of beds is fac in g by it s wide r front toward s the main stress . this leads to the redistributi on or the int ermedi ­ at e and the least principle stress (a2 and a j ), resulting with the most e ffici ent consequence: bending of beds and folding. the folding is accom panied by the addi ­ ti onal compensation or stress in the form of re lease along the compression cleavage of the axial plane. the c stage is characteriscd by the comple te change o f geo logical rc la ti ons, since the most im portant con ­ tractional change resulted in tectonic transport paralle l with the least principal stress (j3' sedim entation ceased o r is colltinued under di fferent cond itio ns a t a different locatioll. during stage c of the laramian t ec~ ionic phase wide areas were uplifted and emerged (not onl y the area of the former carbonate platform ), whil e durin g the c stage of the pyrenean pha se there was a shift from the shallow-water carbonate sedimentation to the deposition of flysch. the same kinematic stage dur­ ing the neotectonic phase resulted in the final orogeny. advancing deformation leads to the increase of the fo ld compression index, and a hi gher inclination o f the charac teris ti c southern verge nce of the neotec tonic contracti on. the only remaining resistance to the main stress is re presented by the ductilit y of the fo ld mate­ rial. overcoming the ducti li ty during the stage d leads to the re leas ing or [o lds, and their breaki ng alo ng the zone o f the least difference between the resistance and the tangential stress . thi s zone is represented by the sliding set of the second hoi generation. in concordance with the large structural form s, kilometer-scale hoi sets of reverse fault s with perpendicular (n-s) cicci metre to metre-scale tectoglyphs, were formed. the most impre­ ssive consequence of the neotectonic contracti on of the is land of i-i var was the formation of the thrust-shccts from the fo rmer fold s, wit h southern vergence (" the hvar st ri ke") . 6 1 t hrust-s heets, instead of "the s ing le island thrust­ sheet" as usually quoted in the lite rature, therefore rep­ resent the structural essence of the island of hvar. so far established opi nions on only one thrust-sheet were probabl y based on a very remarkable contact of the front or the southernmost thrust-sheet with fl ysch , and the apparently continuous succession between the core and the younger deposits. however, it should be noted that the flysch represents only the youngest deposi ts in the succession, not a continuous surface used for thrust­ shcet motion. by the nature or deformat ion of the wider structural fabric, it is only possible to conclude that this southernmost thrust-sheet represent s the first, i.e. the oldes t thrust-sheet structure. towards the north succes­ sivel y younger thrust-sheets of the neotectonic stage d could be found. moreover, opinions on only one thrust­ sheet structu re imply that stage c consisted of a single, huge rold , which had reworked the entire o lder pyre­ nean structural fabric (also supposed to be composed of a single, huge fold ). existing re lics of older, pre-neo­ tecto nic fold s , indicate that thi s was definite ly not the case. the neotectonic stage c fofmed so many en eche­ lon fold s because it first re fo lded ihe maj ority of the older structures, and then included them into the thrust­ sheet stru ct ures . the cau se for th e apparent integral core of the island (or apparent sin gle is land thrust­ sheet) could probably have been a very persistent and strong neotectonic compress ion , resulting in contrac­ ti on or folds and formatio n of th rust-sheets, as well as in the in tegration of tectonically reduced corcs into the new, secondary core, and reduced frontal paris of folds int o the new, secondary front ( fig. 6). t he k inemat ic succession from one stage to the other, therefore. repre­ sents substilul ion of already "consumed" structural form s with the more resistant ones. successively, "coi1 sumed" elements were integrated int o a large res istant st ructure, act ing like a sin gle thrust-sheet in contact with flysch. the kinematic stage e represents an e ven more character istic fcature of th e is land of hvar than it s strike. although the loca l occurrences of the defonna­ tions of this stage were found a ll over the dinarides , on the island of i-i var they are an inevitable feature of the complete neotectonic structural fabric, down to outcrop level. t hese deformation s are partl y the result of the specific regional geotectonic position of the island (as a protruded segment of the neotectonic overthrusting of the dinarides on the adria ti c pl atform ), but they are also a consequence of the inle rna l structural fabric of the island of hvar. nu merous reduced thrus t-sheets, composing the apparent integral structure of the island , have under the inten sified strain begun to respond autonomously to the stress. each thrust-sheet, from the smallest to the largest , was released alo ng the new deformationa l se t of hoi joint s and fau lt s of the kine­ mati c stage e. this third ge nerati on o f hoi reverse faulls, together with earlier ha l reverse rault s of stage d, formed a conjugated hoi se t. thi s res ult ed in the conjugation of thrust-sheets of all scales, and complete 62 1 2 d fi g. 7 the sequence of deformation from conlraction (i) to extension (2) and grav itati ona l joints (3). si. 7 slijed dcfonn inmja ad kol1trakcijc (i.) do ckstcnzije (2.) i grav­ itacijskih hoi pukolinn (3.). conjugation of the integrated thrust-sheet of the is land of hvar. towards the south fold s and thrust-sheets are of southern vergence, and towards the north they are of the northern verge nce. the tangential stress was con­ sumed in both directions of the reverse movements, in this way increasing the tcctonical tran sport along the ax is of the leas t principle s tress (cr, ). hinges of the st ructures were in the pos ition of the decreased lateral pressure, resulting with the opening of the older dis­ junctive se ts of the a. band c stages. the kinemat ic stage f comprises the youngest set of the neotecton ic tangent ial deformations on the island of hvai'. the global s tress already overcame the resistance of the fo lds and thrust-sheets as deformation of stage e procecded. in this way, stage f could be compared with slage b, bu t of a higher de fomlational level: it is char­ acte rised by the reac ti vation of the stage b li rst genera­ tion of hoi fault se ts. the f stage represents, therefore, the fourth hoi generation, characterised by the intensive hori zonta l movements along the left and right s trike­ slip faults, usually c lltting all parts of the hvar structur­ al fabric (fig. 1). it comprises large-scale faults with limoniti zcd surfaces and dccimetre-scale subhorizontal teetoglyphs. in a complex structural fabric , like that of the island of hvar, kinematic stages follow each 0 1 her according to the struc tural maturity of each st ru ctural segment. therefore, duc to the progression of the neotectonic s tress toward s the south, each zone is practically in a different kinematic stage at the salllc time. geologia cro:uicn 50/1 the question of the inlluencc of extensional phases and extension was omitted in the above analys is. their inllucnce is much more predic table than that o r contrac­ tional phases, becausc they certainly follow after each contractional phase. folded deposits , when exempt from the tangential s tress and stimulated by the reg ional widening. aimed to rees tablish their primary form due to thei r preserved elasticity. however, soon they exceed their c lasticity limit, resu lting in the formation of the extensiona l joints in the zone of the b-axis. s ince tangential stress was subsequent ly completely substituted by the gravita tion­ a l force , ex tensional joints in the zone of the b-axis were reac tivated into the gravitational hoi set of conju­ gated s lid ing joints (fig. 7). along these jo int se ts ant iforllls ascended and synforllls descended, similar to the isostatic movements. without this cyclic succession of the tangent ia l and rad ial tecton ic movements, the reestablishment of sedi ­ mentation at the same locality would not be possible. during the exte nsion al phase the upliftcd mountain ranges were oattcned, and the erosion was lowercd enough for depos ition to become reestablished. thus, on the island of hvar the aptian emergence was suc­ ceeded by the upper albian immersion, the a lbian emergence by the cenomanian immersion, etc. the nex t tangent ial phase appeared only when the velocity of the horizontal movement of the african plate increased enough to dominate the rotational ve loc­ ity. along a new vector of tota l movement a new com­ press ion of the global s tress was generated, be ing recogn ised as the new tectonic tangential phase. 3. references aljjnoy ic, b. , prelogoyic, e. & skoko, d. ( 1987) : novi podae i 0 dubinsko-geolos koj gradi i se izmotektonski aktivnim zonama u jugoslaviji.­ geol. vjesnik, 40, 255-263. aljinoyic, b., pr elogoy ic, e. & skoko, d. ( 1990): tectonic processes and the contac t of the adria tic platform and dinarides in the area of thc northern dalm atia. proc. of the int. cont". on mechanics of jointed and faulted rocks, 179182, a.a. balkema, rotherdam-brookfield. marincic, s. (1981): eoeenski f1is jadranskog pojasa.geol. vjesnik, 34, 27-38. marincic: i'eclonic slruclure of the island of hvar (soulhern croal;a) 63 tektonska struktura otoka hvara stanko marincic 1. uvod razvoj gcolosk ih naslaga otoka i-ivara, od neokoma do cocen-oligocena (si. 1), svjedoe i daje ovo podrueje ii vise navrata prctrpjclo promjenc izazvanc tektonskim pokreti­ ma. dobro su npr. izrazene cmerzijc aptskih i albskih naslaga s lieno kao i si rom krskih dinarida, ali ni u jed nom ni u drugolll s lucaju ove pojave nisu i spccifieki detcrmini­ rane. za sada nisu prcpoznali bilo kakvi rclevanlni pokaza­ telji 0 lipu slrllkwrnih deformacija prema kojillli.t bi se illoglo zak ljueiti 0 tcktonskoj naravi ov ih emerzija i nji­ hovoj uzrocnoj vezi s odredenilll tektonskim fazama. tek su na kraju gornje krcde, za rclativno kratkotrajnog preki­ da sedilllcnlaeije platformnih karbonala, u dovoljnoj mjeri izrazenc strukturnc dcfonnacije svojstvcne izv. laramijskoj tangencijalnoj tektonskoj fazio analogn im je postupkom jos dclerminiran ucinak djclovanja lutct-oligocenske tzv. pircnej skc tangencijalnc faze i neogensko-kvartarne ncolektonskc tangencijalnc faze. ovakvo nazivlje tcktonskih faza je zadrzano zbog nji ­ hove pov ijcsnc ukorjcnjcnosti i prcpoznatljivosti u nasoj geoloskoj literaturi, pa i zalo sto ne postoji ncko drugo. i311duci cia sll najstariji definirani tektonski pokreti ovog podrllcja laramijski , oni su llvjelno oznaccni kao prva ick­ lonska faza f i , pirenejska kao f ii i neotektonska faza kaoftll 2. kinematika deformiranja i tektonske faze najuocljivija posljedica djelovanja tangcncijalne tek­ tonske faze na sedimentacijsk i s ustav je duzi iii kraci prekid scelimenlacije (emerzija) iii pak, bitnc izmjcne velikih taloznih sustava (plalformni karbonati flii; molasa). po lome se zapazaju kao dogadaji u odredenom geo loskom vrcmcnu. mecllltim, ne moze sc bas za svaki prekid ll sedimentac iji a priori tvreliti da je izazvan tekto­ nikom dok sc ne clokazll tektonski iii ini uzroci. bez u[vrdenih uzroka, scdimentacijskc promjcne os tajll samo na rangll konstatac ije prepoznatog facijesa. pod tangcncijalnim stresom, silom kinematskih uvjeta duza os (b-os) defonnacijskog sklopa je u polozaju nor­ male na sires. takoder i bora, kao optimaln a referentna deformacija sklopa, ima b-os normalnll na strcs. sva gcolllct rija bore i svi pripadajllci joj deformacijski sllsiavi (krila, amplituda, raspon , indeks, 8-os, vergeneija , pllko­ tine itd.) kincmatski sll iskazi orijen l iranog slresa. praklicki , pod stresom bilo kojc orijcntacije, deformiranje napreduje iclenticnirn kinematskim tijekom koji se manifc­ stira 11 kinematskim skokovima kao rang stanja eleforma­ cije iii kinematski stadij. u toj su mjeri kinematski stadiji opci obrazac koji ce se poblize obrazloziti na primjcru ncotcktonskog slrllktllrnog sklopa otoka i-ivara. koliko je za neko geolosko tijelo od prcsudne vaznosti prostorna lokacija , loliko je za njegov deronnacijski sklop prostorna orijcntacija. dakako, oba su aspekla konlrolirana geo loskim vremcnom i bas zbog toga ce autenticne pri­ marne eleformaeije ncposredno svjedocili 0 pravcu regio­ nalnog stresa kao 0 prcpoznat ljivoj tangencijalnoj tekton­ skoj razi. prislllnost ucinka laramijske fazc f i, osim cmerzije konccm gornje krede, indiciraju mjcstimicni relikti rela­ tivno velikih, metarskih do dekametarskih bora. qve bore s b-osima pruzanja sjever-jug i korcspondirajucim pllkotinskim slistavima, mogle su nastati sarno pod djclo­ vanjem regionalnog tangencijalnog strcsa na pravcu istok­ zapad, elakle, u la ramijskoj teklonskoj fazi. ostaci lm'ami­ jskih bora sacuvali sll prcpoznatljivu gcometri ju na taj nacin sto im je i pirenejska i neotektonska faza prcborala b-osi. promjenom nagiba osi sacuvali sll sc oni dijelovi laramijskih bora koji su kinemalski ugradeni ii konstitllcijll kri la dominantnih neotektonskih bora (trase osnih ravnina laramijskih bora paralclne su s neotcktonskim "a-lincaci­ jama" krila). pod djelovanjem pirenejskc tangeneijalnc tcktonskc faze (f ii ) ii karbonatnoj se platformi ll srednjem eocenll formira flisko korito i pocinje talozenje flisa (marincjc, 1981). ovom fazom pocinje dczintegracija mczozojske karbonatnc platfonne. sinlektonsku scclimcntac iju eoccn­ oligocenskog flisa pod djelovanjem pirenejskog stresa na pravcll jugozapad-sjeveroistok prati podvlaccnje jadranskc platforme poel dinaride. dinaridi sc boraju tvoreei poznate struktllrne fenomcnc obuhvacene pojmovima "dinaridsko pruzanje", "dinaridskc struklllre" (pruzanja sjeverozapad­ jugoistok) s karakteristicnim jugozapadnim vcrgencijama. pircnejske sll bore na podrllcju !-ivara samo mje­ stimicno sacuvanc. zbog izvorno dijagonalnog polozaja prema neotektonskom stresu njihove strllklurne geometrije nisu ni moglc pruziti maksimalni otpor (si. 2). sacuvani su tek oni dijelovi pircncjskih bora koji sll bili u kinc­ malskom polozaju da postanu konstitlltivni clement kr ila veee ncotcktonskc bore. u tim sll slucajcvima zadrzale i pirenejsku jugozapadnu vergcnciju. dapace, neotektonski jc sires ekonomicno koristio svaku zatecenll pircnejskll pllkot inll koja sc mogla ugraditi u njegov dcformacijski slls tav. promijcnila sc samo kinematska fllnkcija starijih pllkotina. obicno lijeve smicne pukotine konjugiranih parova prvc pircncjske hoi generacije poprimaju fllnkciju pukotina osne ravnine, a desne postajll tenzijskc pllkotine neotektonskih bora (si. 2). relativno mali broj utvrdcnih relikata laramijskih i pirenejskih bora u odnosu na dominantne neotektonske bore (si. 3), ne umanjllje principijclno znacenje njihove prisutnosli. pod neotektonskim su strcsom promijenile salllo nagib 8-osi, ali su zadrzale osnovnu orijcntaciju, pa prema tome i medusobno bitno ncporcmeeene polozajc (si. 4). zato je polrcbno islaknllti da je zateceni strukturni prcdcrtcz pod djelovanjem neotcktonskog slresa (sjcvcr­ jug) prcboran, a nc horizonwlno "retrogradno rot iran" oko ncotcktonskc c-osi, kao slo se danas pokllsava tlllllaciti svaka pojava "hvarskog pruzanja" ii dinaridima (uspore­ eliti: aljinovic et al, (990). uostalom , koji bi to stru64 kturni sklap mogao horizontal no rotirati osim navlakc odvoje nc ad korijcna? hvarska ljuska iii ijuskc, nisu u toj siluaciji. evcil tualnc lokalne horizontainc rotacijc duz transkurcntnih (hoi) rasjeda su pojavc na razini izdanka. n i velika sllin<l njihovih difcrcncijaln ih lijcvih krctanja nc doprinosi prcvagi j cdnog smjcra pomaka (rotaciji) jer ih za slican iznos kompenziraju pomaci duz desnih transkurcnl­ nih rasjcda. osim toga, ova krctanja spadaju u dcronnacijc kincmatskog f-stadija (celvrta hoi generacija) koji je llslje­ dio nakon formiranja "hvarskog pruzanja". na konell, na plohama ce la ijusaka juznih ycrgcncija svi su tcktoglifi ugradeni perpendiklliarno niti su zakrivljeni, niti sumarno pokazliju odstupanje od pravea sjever-jug. pojavom novog smjera g lobalnog slresa na pravcu sjevcr-jug, artikulira se neoge nsko-kvartarna neotcktonska tangeneijalna fa za (f iii). podvlaccnje se naslavlja i inten­ zivira, pa se i sama jadranska karbonatna pial forma dezin­ tegrira na nekoliko scgmenala (alj inovic ct ai., 1987), dok sc u dinaridima pojavljlljll strukturne deformacijc pruzanja islok -zapad ("hvarsko pruzanje") s juznim ver­ gene ijama. specifieni geoloski razvoj i gcolektonski po 1 oz.aj jugozapadnc islre, otoka lastova i, vjcrojalno, visa, ukazujll da su oni re likli jadranske karbonalne platformc. otok hvar je, prema tome, did vrlo isturenog navlacnog ozemlja vel ike slrukturnc elaze dinarida blizu zone neo\ck\ol1skog podvlaeenja. u toj je mjcri prctrpio i jaeu kontrakciju koja se odrazila u bogalom sadrzajll slrll ­ ktllrnih dcf"orlllacija neolektonske tangcnc ijalne faze. mada je pravac djclovanja stresa od presudne vaznosti za razllmijevanje geoloskog razvoja [lekog podrueja, s kinclllatskog je aspekla od sekundamog znacaja. idealni (polpuni ) kinematski slijed napredovanja deformacija je identican li bilo kojoj orijentaeiji stresa pa i u neotckton­ skolll primjeru hvara ima vrijednosti opeeg obrase<.t. promjene su llvjclno oznaccnc kao a, b, c, d, e, f stadi ­ ji kincmatskog razvoja, deriniranog prema kriteriju progre­ sijc pojavljivanja bilnih tangeneijalnih defonnaeijskih sus­ (a va (sl. 5). prva reakcija na komprcsiju j e tenzija koja paralelno s ravninom g lavnog i srednjeg slresa (0 1 o2) otvara tcnzi­ jske zjapecc pukoline kinematskog a-stadija. ove puko­ tine imaju malo proslorilo protezanje (eentimelarskih do decimetarsk ih velieina) pa o bicllo ne presjecaju ni eijelu dcbljinu sloja. porcd toga se dobro isticu zbog karakle­ risticnih pcrastih objika ispunjenih bijclim sparikaic itom. znaeajno jc cia se be pojavljuju na bilo kojelll mjeslli 11 ravnini 01 0 2' vec samo u zonama na koj ima je razlika olpornosti i langeneijalnog prit iska najmanja (ho[-zona poel kutolll od 45° prema praveu glavnog slresa, modifici­ rana za kul unutrasnjeg trenja ll vapnelleima iznosi eea 38°). u kinematskolll b-stadiju dolazi clo kidanja hoi-zone i sm ieanja po konjugiranom paru hoi pukotina (prva hoi gcneraeija). pukotine su ecntimctarskih do illctarsk ih duzi ­ na, potpuno presjeeaju sloj al i nc penetriraju u drugi sloj; zastaju na meciuslojnolll diskontinuiletu. velieinu il11 zapravo kontrolira debljina sloja, pa se ne mogu razviti do kvalitcte rasjeda. cesto iskazuju mil imctarska lijeva, odnosno ciesna kretanja s lllalim tekloglifima koji su para­ lelni sa slojem. ovi mali pomaci, clakako, razmicu i tenzi­ jske pukotinc kinemalskog a-stadija kojc sli u istoj zoni prethodile smienim pukolinama. nazalost, kod lih sc slueajeva brka redoslijed dogadaja, pa se uslalilo kao prageologia croalica 50/! vilo, da sll sl11icne hoi pukoline krctanjelll izazvalc sekun­ darnu pojavu tenzijskih pllkotina (lad a ill razlikuju kao "peraste pukotine"). a i b stad ijcm jc g lavni s tres kompenziran na razini otpora sto ga je pruzao svaki sloj zasebno. naslavkom djelovanja stresa, u c-stadiju, potroseni ustroj olpora zamjenjujc krupniji sklop, skup slojeva (pakel). c-staclijem opiruea mas a teii holllogenizaciji, okrupnjavanju, pa su od ovog slaclija i sve defonnacijc krupnije. opirlici se materi­ jalnoj dezintegraeiji, homogcni sc sk lop slojeva postavlja sirom frol1tom prema glavnom stresu. na ovll rcakcijll olpora, glavni sires redistribuira sporcdne st resove (g2 i ( 3) slo je rezultiralo minimalno 1110g11com posljed ieolll savi­ j anjem slojcva i boranjem. boranje je jos popraeeno doda­ tnom kompenzacijom stresa "popustanjcm" po komprcsi­ jskom klivazu osne ravnine. c-sladij donosi najznacajniju kontrakcijsku promjenu . na sirem planu ovaj strukturni doseg naznaeava i pro­ mjellu ukupnih geoloskih odnosa. dominantan geoloski proces postaje tektonski transport (na praveu najslabijeg strcsa 03). sedimentacija prestaje, odnosno nastavlja se u izmijenjcnilll uvjetima na nekom drugol11 mjestu. u kine­ matskom c-staciijll laramijske tektons ke faze izdizu se i okopnjavaju siroki prostori (ne salllo karbonatne plat­ forme), a u c-stadijll pirenej ske faze mijenja se velik i scd i­ mentacijski sustav platrortnskih karbonata ii flis. ncolek­ lonskim c-sladijem, mog lo bi se ree i, pocinje pos ljednje izclizanje golja . n apredovanjem dcformiranja raste indcks sl isnutosti bora, a zalim i naglaseni nagib karaklc ristiene juzne ver­ gencije neotektonske kontrakeije . olpor glavl10m slrcsu jos pruza duktilnost matc rijalne grade bora. nadvladava­ njcm duktilnosti, u kinelllatskom d-stadiju, bore popustaju i kidaju se po zon i na kojimaje razlika otpornosti i langen­ cijalnog stresa najmanja po smienom hoi sustavu drllge gcncraeije. suglasno velikim strukturnim formama, nasla ­ .ill kilomct arski hoi sllstavi rcverznih rasjeda s per­ pendiklllarno llgradenim (sjevcr-jug) dec illlelarskim do metarskim tektoglifima. od bora se formirajll ijuske juznih vergeneija kao najslikovitiji odraz ncotektonskc kontra­ keij e otoka hvara ("hvarsko pruzanje"). ljuskc su, dakle, strukturna sustina oloka hvara , a ne "otoena ijuska" kako se rcclovito opisllje u geoloskoj lilera­ turi. moze sc prctpostaviti cia j e oejeni 0 j ednoj ijuski doprinio markantni kontakt ecla najjuzn ije ijuske s fiisom, kao i privid 0 re lativno kontinuiranom zatvaranjll naslaga integrirane jczgre s mladim naslagam<l. prvo: rjis sc ovdje pojavljuje samo kao najmladi sediment i nije u funkeiji suvisle pod loge po kojoj se ijuska krece. po prirodi kinc­ matskih uvjeta napredovanja derormiranja sireg s trll­ kturnog sklopa, moze sc reci jeciino to da jc ova najjuznija ijuska ujcdno i prva pojava ijuskanja. sjcvcrnije od njc sljede sve mladc ijuske kinematskog d-staclija neotek ­ tonskc kompresije. drugo: ideja 0 jcclnoj ijuski podrazlimi­ jeva kinclllatski predstadij (c) jednc jedine goicmc bore s kojom je preraden eijcli zateeeni pirenejski strukturni sklop, kao da se i on sastojao salllo od jednc goleme borc. relikti bora ranijih, predneotektonskih faza, ukazuju dol to nijc tocno. neoteklonski c-stadij forrnirao je brojnc csalonirane bore jcr j e morae prcborati vecinu zaleeeni h struktura starijih tektonskih faza i tek ih potom med iti ii ijuskc. sto je dakle uzrok prividno integralne jezgre, odnosno inlegralne olocne ijuske? moglo bi se reci upoma i snazna ncoteklonska kompresija koja sabija i ljuska bore marincic: tectonic slnklure of the [s[;llld or h var (southern croali;l) do clubokog tektonskog kontakta jczgre s jezgrom i spaja­ nja rcduciranih cela bora u jedno sekundarno te lo (si. 6). kincmatski put oel staclija do stadija ustvari je put zamjena svladan ih o pi rucih formi s otpornijom geomctrijskom graclom . od "potrosenih" se elemcnata sastavlja, integrira , vcl ika otporna slruktura koja na koncu runkcionira, a tako sc i dozivljava, kao jedna ve lika otocna ijuska s aktualn im celom u kontaktu s rii som. za kinematski e-staclij bi se moglo reci cia je vjerodo­ stojn ije hvarsko svojslvo i od sarnog "hvarskog pruzanja". lako sli sirom dinaricla poznate lokalne pojave e-deforma­ eija, one su nezaob ilazni ci nilac ukupnog neotcktonskog sklopa c ij clog podrucja hvara, do razine izdanka. one su zapravo puni odraz specificnog rcgionalnog geotektonskog polozaja otoka hvara (kola islurcnog segment a neotekton ­ skog navlacenja dinarida na laclransku pl atfo rmu) ali takoder i odraz int ernog stanja stru kturnog ustroj a hvarskog sklopa. naime, brojne reducirane ij uskc kojc sas­ tav lj aj u priviclno hom ogenll otocnu struktu ru, pod pojacani m naprczanjem poc inju iskazivat i autonornnc odgovorc na sires . svaka se osnovna ijuska ponaosob, ocl najvece do naj rnanj c, os lobada pri tiska popll stanj em po novom deforrnaeijskom sustavu hoi pukotina i rasjeda kinemalskog e-stadija. ova sc trcca gcneracija hoi reverzni h rasjcda prikljucuje ranijcrn hoi rcvcrznom sus­ lav u d-slad ija u konjugirani hoi pa r. pos ljediea jc konjugi ­ ranje ijusaka sv ih podrucja vc lic ina i ukupno konjug iranje hvars kc integriranc ijuske. juz.no oel njezi ne si met ra lne ravn inc su bore i iju ske ju zne vergeneije s nav lacenjern prema j ugu, dok se sjeverno od simetralne ravnine it e­ stadiju fortnirajll sjevernc ve rgcncijc bora i ijusaka prellla sjeveru. tangeneija lni se stres trosi na oba revcrzna kre­ tanja slo udvosl rucuj e te ktonski transport na praveu cry tjcmena struktura do laz i u polozaj smanjcnog bocllog pri ­ liska, pa se s ire i otvaraj ll sta riji disjunklivni sllstavi a, b i c-stad ij a. kinelllatski f-st ad ij obuh vaca najmladi suslav ncolek­ tonskih tangcncijalnih dcformaeija otoka hvara. globalni je stres fakticki sv ladao kinematsku sust inu otpora bore ijuske, pa sc dcformiranjc e-s klopa nasta vlja , ltvjetno receno, s licno ponavljanju ll -s tacl ij a vise cl e form acijskc 65 razine, odnosno f-s tad ijem . u bi ti se reakti v ira prva hoi gcneracija konjugiranih parova rasjecla b-stadija. f-stadij se pojav ljuje kao cetvrta hoi generae ija s naglasellim hori­ zontalnim kreta njem duz lij ev ih i desn ih tran skurentnih rasjeda koji ces to presjecaju sve strukturnc form e hvarskog sklopa (s i. i ). isti cu se ve likim rasjed ima s limonitiziranim plohama i dccimetarskim subhorizontal­ nim icktoglirima. u komplcksnom st rukturnom sklopll kao sto je podrucj e hvara , kinematski se stadiji pojavljuju s ljedorn strukturne zrelost i svakog strukturnog segmenta. zbog loga se, na pl anu progresijc ncotektonskog stresa prcma jugu, od zone do zone prakticki istovrerneno nalazc razliciti kinematski stadiji. u ovom je prikazu zapostavljeno pitanje sudjelovanja ekstcnzijsk ih faza i ekstenzijskih tektonskih pokrcta c iji jc uc inak , za razliku od kontrakeijskih (tangcncijalnih) faza, redov ito prcdvid iv. nairne, one nezaobilazno s ljecle prestanak djclovanja svakc kontrakcijske faze. borane naslage oslobodene tangcncijalnog sl resa i pot­ pomognute s irenj em prostora, sac uvanim e last ic itetom tcie vracanju prema prvotnom stanju formc. medutim , ubrzo prelazc g ranicu elasticiteta zbog cega se li zoni b-osi otvaraju ekstenzijske pllkotine. bllduci cia tangcnc ij a lni stres u potpunosti smje njujc s ila grav itacije, ckstenzijske sc pukotine zone b-osi akli viraj u u gravi tacijski hal sll stav konjugiranih parova kliznih pukotina (s i. 7). po njima sc, popu t izos tat skog krctanja, antiformc g ravit acijski spustaju, a sinforlllne izdizu. bez ove cik licne kornplementarne izmjene tangeneija­ lnih i radijalnih lekton skih pokrcta, ne bi bila illoguca obnova seciimentacijc na istom mj cstll. faza ekstenz ije poravnava izd ignuto gorjc i sni zava crozijsku bazu do razine obnove uvjeta sccl imentae ije. tako na i-ivaru na apt ­ skoj emerz ij i sl ijed i irnerzija gornjeg alba, nakon emerzije alba c10lazi imcrzija ccnomana itd. nova sc tangenc ijalna faza pojavljuje tek kada brzilla kretanja africke ploce poslaje izrazito veca od brz inc rolacije. po nc izbjcz.llo novolll vek toru ukupnog kretanja , generira se nova kompresija g lobalnog slresa kao prepo­ znatljiva tcktonska langencijalna faza. manuscript received april 3, 1995. revised manuscript accepted april 28, 1997. 66 geolog i;l croalica 5011 plate! fig. i relics of the laramian fold (1' i, b 180/20) in the southern limb of the central neotectonic anticline (1' 1il , b 270/1 0) of the island of l-lvar; vicini ty of lel sa. fig. 2 relics of the laramian fold (f i, b 5/10) near vrboska. tabla 1 si. i relikt laramijske bore (1' i, b 180/20) u juinom hilu sreclisnje neote~10nske antikl inale (1' ill , b 270/10) otoka t-ivara; poclrucje jclsc. si. 2 relikt laramijske bore (1' i, b 5/ 10) kod vrboskc. marincic plat e i 67 bfi 1 68 geologia croatica 50/1 plate 11 fig. i relics of the pyrenean fold (f 11, b 297/8) with preserved south-western vergence; vrboska. fig. 2 neotectonic fold (f iii) of the northern coast of the island of hvar with secondary northern vergencc of the e stage; mala stiniva cove. tabla ii sl. i relikt pirenejske bore (f ii , b 297/8) sa sacuvanom jugozapadnom vcrgencijom; vrboska. si. 2 neotektonska (f ill) bora sjeverne obalc atoka hvara sa sckundarnom sjcvcrnol11 vcrgcncijom e-stad ija; uvala mala stin iva. m:lrillcic , .' i ------plate ii , " " , .~.-""~' ' "\ ~... ~ ...... :.\~:". .; 69 70 geologia croatica 50/1 plate iii fi gs. i and 2 small-scale neotectonic folds (f iii) with the northern vergence of the e stage; stari grad. tabla 1ii si. i i 2 male neotcktonske (f iii) bore sjevernc vergcncijc kinematskog e-stadija; stari grad. plat e !!! 71 72 gcologi;l croatica 501 1 plate iv fig. i hoi joints of the b stage in the kinematic fabric of the fold (c stage); northern limb of the anticline in the dubac cove. fig.2 identical kinematic stages in the core or the syncline in the zavala cove (near stari grad). tabla iv si. i hoi pukotine b-stadija u kinematskom sklopu bore (c-s tadij); sjeverno krilo antiklinale u uvali dubae. si. 2 idcnt icno kincmatsko stanjc u dnu sinklinalc u uvali zavala (slarigraciski zajjcv). marin6': plate iv ~----" -73 geolog ia croa!ica 5011 plate v fig. 1 conjugated hoi joints or the kinematic stage b; bedding surface near vrboska. fig. 2 frontal part of the ncotcctoni c(f iii) thrust-shect of the uppcr cretaceous limestone overlhrusling palaeo­ gene flysch. metre-scale "a"lineat ions (iccloglyphs) with movement towards the south; city of hvar. tabla v sl. i konjugirane hoi pukotine kinclllatskog b-stadija; slojna ploha kod vrboskc. si. 2 cejo neotcklonske (f ill) ijuskc gornjokrednog vapnenca navucenog na palcogcnski riis. mctarske "a" lin­ eacije (tcktoglifi) s krclanjem prcma jugll; grad hvar. plate v 75 76 geologia croalica 50/1 plate vi fig. 1 tensional joints of the kinematic stage a (feather-like shaped joints) appearing in the hoi zone before hoi joints. bedding surface in carnian limestones in the samoborska gora mt. tabla vi si. i tcnzijskc pukotine kinematskog a-stadija ("perastc pukoline"). pojavljuju se u ha l zoni prijc hoi pukotina; slojna ploha karnickog vapnenca samoborske gore. marincic plate vi 77 hot 78 geologia croatica 50/1 1. introduction lepidodendron dawsonii bell 1938 is a fairly common lepidophyte component in the late asturian of sydney coalfield, canada (fig. 1a & b), and ranges from the emery seam to the highest strata at point aconi (fig. 1c). its phytostratigraphic utility is limited, but bell (1966, pl. xxvii, fig. 5) believed it was early westphalian d in the canadian carboniferous maritime provinces. thomas (2009, table 6) stated that it was not found outside the sydney basin in variscan euramerica, i.e., it was endemic. the specimen is significant (pl. 1a) because of the dual preservation as 1) a coalified compression, typical of fossil plants in the sydney coalfield (pls. 1b & c), and 2) as rare fossilized-cuticle (pls. 2a & b), i.e., this is the only specimen known from the sydney coalfield. the co-occurrence of coal and cuticle in the specimen invites analogy with a coal-seam, particularly as lycophytes provided considerable biomass for coal-seam accumulation (e.g., arnold, 1947, p. 94; dimichele et al., 1985; cleal et al., 2010). here, the focus is on the two preservation states in one contiguous specimen of l. dawsonii. as each is capable of providing its own spectrochemical information as a consequence of its fossilization history, i.e., coalification and natural maceration (zodrow & mastalerz, 2009). though cuticular information is provided taxonomy is not an objective here and is not discussed further. ab stra ct lepidodendron dawsonii bell 1938 is an endemic species of late asturian age in the canadian sydney coalfield, with conspicuous elongate leaf cushions. the study specimen, 35 cm long and 10 cm wide, represents a dichotomous bough from the tree crown in which the inner part of one side is black and compression-preserved, whereas the one in contact with the entombing rock matrix is dark-amber in colour and fossilized-cuticle preserved. only stomatal pits and cuticular details are preserved. comparison of these preservation states, based on fourier transform infrared (ftir) spectrometry, and flash pyrolysis gas chromatography mass spectroscopy (py-gc/ms), demonstrate sufficient differences in chemistry to be able to link the two preservation states with differing pathways of organic matter transformation (diagenesis). the aliphatic-hydrocarbon chains of the cuticles are comparatively shorter and more branched than the longer chains of the compressions. py-gc/ms results support the presence of hydrocarbon markers of plant cuticles. the high abundances of c1 and -c2 alkylphenols and c1 and -c2 alkylbenzenes in pyrolysates are likely derived from maturing lignin or lignin-like biomacromolecules. we suggest comparison of l. dawsonii’s cuticles with lepidodendron coal macerals in chinese permian leping coal, and with suberinite. keywords: ftir, flash pyrolysis, bark, compression-fossilized-cuticle, lepidodendron geologia croaticageologia croatica lepidodendron dawsonii: functional groups and pyrolysates of compression and fossilized-cuticle (late asturian, canada)  erwin l. zodrow1, maria mastalerz2 and robert helleur3 1 palaeobotanical laboratory, cape breton university, sydney, nova scotia, canada, b1p 6l2; (corresponding author: erwin_zodrow@cbu.ca) 2 indiana university, indiana geological survey, bloomington, in 47405-2208, usa; (mmastale@indiana.edu) 3 department of chemistry, memorial university of newfoundland, st. john’s, newfoundland and labrador, canada; (rhelleur@mun.ca) doi: 104154/gc.2012.26 geologia croatica 65/3 367–374 4 figs. 5 tabs. 2 pls. zagreb 2012 geologia croatica 65/3geologia croatica 368 plate 1 lepidodendron dawsonii a entire specimen, where x marks the base of the dichotomy and sample location? (this is what x is referred to in the text as representing). b compressed leaf cushions in situ. c lose compressed leaf-cushion material after 30-min hf treatment. specimen 980-391-1 in the palaeobotanical collection of cape breton university. plate 2 lepidodendron dawsonii a amber-coloured fossilized-leaf cushions in situ. b fossilized-leaf cushions after 20-min hf treatment. c cuticle of (b) is in focus above the lower surface. x125. slide 980-391-1/2. d cuticle (right) and lower surface (left). x125. slide 980-3911/1. the round or oval holes are stomatal pits. zodrow et al.: lepidodendron dawsonii: functional groups and pyrolysates of compression and fossilized-cuticle (late asturian, canada) geologia croatica 369 2. preservations and cuticular morphology the specimen originated from a section 1 m above the lloyd cove seam in the unaltered shaly roof rock, at the base of the cantabrian substage (fig. 1c), that is known to be very fossil-rich and biodiverse (e.g., zodrow, 2002). its dichotomizing habit (pl. 1a) is typical for the crown of lepidodendron sternberg (hirmer, 1927, figs. 200–202; thomas, 1966). the cortex of the inner surface of the branch that is pressed upon the prolongation is coalified with preserved cuticle, whereas the cortex facing the entombing rock matrix (fig. 2) is fossilized as cuticle sensu zodrow & mastalerz (2009). leaf cushions are slender ca. 20 mm long and 5 mm wide and separated by secondary growth enlargements (pl. 1b, pl. 2a and b); see also thomas (1966, fig. 5b). the leaf scars are rhomboidal in shape, and bell (1938) compared older stems of l. dawsonii with l. rimosum. the epidermis of both preservation states shows little morphological difference and is diaphanous and very thin. details of stomatal apparatuses are not preserved, only stomatal pits (thomas, 1966, fig. 3) that are oval to round in shape, sometimes touching or merging into one another, averaging for the longer diameter 39 µm, ranging from 30 µm – 50 µm, n= 40. two cell morphologies are evident, based not so much on their variability which is considerable (compare pl. 2c figure 1: a) canada. b) canadian maritimes basin. c) local coal-lithostratigraphy of the sydney coalfield, nova scotia, where x marks the lloyd cove seam for the sample. figure 2: study specimen showing sample locations for analyses (schematic), where fc stands for fossilized-cuticle and comp for compression. geologia croatica 65/3geologia croatica 370 and d), but on differences in average ratios of length/width (tab. 1). the elongate cells probably represent the epidermis above the leaf scar (see thomas, 1966, p. 297; 1970). in either morphology anticlinal walls are straight. 3. material and methods samples were chipped from a location marked x on pl. 1a, supplemented by fossilized-cuticles from the lower righthand edge of the specimen. hf (48 %) was used to free all sample materials that were then washed and rinsed in distilled water for one week to eliminate as much acidic residue as possible. for a clearer view of the cuticular topography under a binocular microscope equipped with nomarski capability, the fossilized-cuticles were lightly macerated (3 h), using schulze’s well-known oxidative process (cleal & zodrow, 1989; and others). compression and macerated fossilized-cuticle samples for ir (infrared) spectra were prepared by the pellet method, where 250 mg of kbr were finely ground with ca. 1.2 to 1.5 mg of the organic material, and pressed for 20 min (20,000 psi) into a 1-cm diameter pellet. ir analysis was performed on a nicolet thermo-electron 6700 spectrometer, accumulating 256 scans at a resolution of 4 cm–1 wavenumber. assignments of functional groups were according to painter et al. (1981), wang & griffiths (1985), and goodarzi & mcfarlane (1991). the flash pyrolysis (py) of 0.6 mg, and subsequent analysis of the pyrolysates were carried out using a frontier lab vertical micro-furnace at 600 °c which was interfaced to a hp gc/ms with a 30m x 0.25mm (0.25 um thickness) db1701 capillary column. all interface temperatures were at 260 °c. the gc oven program is 35 °c (initial) to 265 °c at 7 °/min temperature ramp. the identity of the peaks was verified using standards. elemental analyses for nitrogen, carbon, hydrogen, sulfur, and oxygen (by difference) were performed in duplicate (2–3 mg) on a carlo erba ea 1108 elemental analyzer, and the averages are presented in table 2. 4. discussion of results the mid range ir spectrum used for interpreting organic analyses, 4000–400 cm–1 wavenumber, is subdivided into two peak-containing regions, separated by a broad interval of low or no absorbance. the lower-wavenumber region ranges from 1800 to 700 cm–1 and includes the 1800–1600 cm–1 region with oxygen-containing and aromatic moieties. comparative wave-number changes/differences/shifts in this region reflect diagenetic influence, e.g. particularly oxidation (berner, 1980) through geological time. the second peak series is located in the 3000–2800 cm–1 region and relates to aliphatic side-chain characteristics as signals from the biopolymer-cuticle matrix (stark & tian, 2006). from this region the ch2/ch3 ratios were calculated after deconvolution of bands, with the band width and band enhancement kept constant. but caution is necessary in the interpretation, as the ratio is sensitive to changes in maturity levels (van bergen et al., 2004). qualitative examination of ftir spectra shows close similarity between the fossilized-cuticle and compression spectra (fig. 3), i.e., all show distinct aliphatic bands in the 3000–2800 cm–1 aliphatic stretching region, and in the 1500– 1300 cm–1 aliphatic bending region. the most prominent band at 1607 cm–1 is assigned to aromatic carbon on the basis of the position of the peak as well as its shape. aromatic hydrogen bands in the 3100–3000 cm–1 region are very small but present in all spectra. in the 900–700 cm–1 aromatic outof-plane region, only one band at ~750cm–1 is detected that indicates four adjacent c-h groups. a slight difference is table 2: elemental analyses (weight %) of the fossilized cuticle, compression, and coal (vitrain) from the underlying lloyd cove seam. n c h s fossilized cuticle 1.71 67.85 4.70 5.35 compression 1.68 65.50 4.48 4.82 coal 1.36 75.92 5.22 nd nd not determined (lyons et al., 1995, table 1). table 3: sample weights for ftir spectra. spectrum weight spectrum weight comp1 1.1 2fc 1.1 comp2 1.1 1fc 1.2 comp3 1.1 3fc 1.3 comp compression, fc fossilized cuticle. figure 3: composite presentation of the spectra, where fc is fossilized cuticle, and comp the compression. the benzene ring (right) symbolizes the oxygenated aromatics and the chain the aliphatic hydrocarbon chain. table 1: average cellular length/width ratios (µm). cushion part n range average ratio length/ widthlength width length width above leaf scar 22 22–65 7–30 34.8 19.4 ca. 2 18 45–114 5–19 74.8 12.4 ca. 6 zodrow et al.: lepidodendron dawsonii: functional groups and pyrolysates of compression and fossilized-cuticle (late asturian, canada) geologia croatica 371 noted in relative band absorbance; it is higher for 1fc (fossilized cuticle) and 3fc, correlating with increasing sample weight (tab. 3) because the spectra are not weight-normalized. this observation conforms to the empirical lambertbeer law that relates absorption of light to the amount of material through which the light travels. closer semi-quantitative evaluation and comparison of spectra can be achieved by means of integration of area under spectral bands, and calculation of their ratios (see zodrow & mastalerz, 2007; d’angelo et al., 2011a). table 4 lists the spectral regions and ftir-derived ratios selected as being the most useful for the purpose of this study. in effect, the ratios have a semi-quantitative chemical meaning and have been utilized, for example, in palaeochemotaxonomic studies (lyons et al., 1995; zodrow & mastalerz, 2001; zodrow et al., 2003), characterizing morphotypes (zodrow et al., 2000), reconstructing kerogen (d’angelo et al., 2011a), or in documenting preservation variability (d’angelo et al., 2011b). table 5 summarizes the semi-quantitative chemical data (ftir-derived ratios) that in effect constitute the remaining organic material of the plant we call l. dawsonii, in these particular preservation states. the analytical data (tab. 5) clearly show that in respect to aromaticity some differences exist between the compressions and fossilized-cuticles, with the average aromaticity (ar1) and ar2) being slightly higher for fossilized cuticles, which corresponds to slightly higher elemental carbon (tab. 2). however, the estimated degree of condensation of aromatic ring structure, benzene ring (car1 and car2) is higher for the coaly compression, as is expected. the most noted spectrochemical difference between these two preservation states is, however, for the ch2/ch3 ratios which are consistently smaller (mean 2.24) in fossilized-cuticle vs the compressions (2.60), implying comparatively shorter and more branched hydrocarbon chains in the biomacromolecule for the fossilized-cuticles. this is unexpected, as in our experience with laurasian-gondwanan compression-fossilized-cuticle of the medullosalean foliage of carboniferousupper triassic ages, the reverse is the case, and fossilized-cuticles normally show higher ch2/ch3 ratios (see zodrow et al., 2011, table 4; zodrow & mastalerz, 2009, fig. 5; zodrow et al., 2009, table 6; and d’angelo et al., 2011b, table 4). we mention parenthetically that a similar relationship exists between medullosalean fossilized-cuticles and those that are treated by schulze’s maceration process. in nearly each case, the schulze’s treated fossilized-cuticle revealed higher ch2/ch3 ratios from which comparatively longer and less-branching hydrocarbon chains are interpreted (zodrow et al., 2010, table 3). equally, cuticles obtained by schulze’s process table 4: ftir absorption region and ratios used. absorption regions (cm–1) assignment 3100–3000 aromatic c-h groups in stretching mode 3000–2800 aliphatic c-h groups in stretching mode 1800–1517 c=c plus oxygen-containing groups (carboxyl, carbonyl, ketones, etc) 1500–1300 aliphatic c-h groups in bending mode 900–700 aromatic out-of-plane c-h groupsa ratios interpretation ch2/ch3 in 3000–2800 region relates to aliphatic chain length and degree of branching; larger = longer and less branched chains al/ox (3000–2800)/(1517–1800) estimates proportions of aliphatic c-h groups in relation to the sum of oxygen-containing groups and c=c ar1 (3100–3000)/(3000–2800) indicates aromaticity of organic matter based on aromatic stretching region; larger = more aromatic ar2 (900–700)/(3000–2800) indicates aromaticity of organic matter based on aromatic out-of-plane region; larger = more aromatic car1 (3100–3000)/(1800–1517) estimates degree of condensation of aromatic ring structure based on aromatic stretching region; larger = higher degree of condensation car2 (900–700)/(1800–1517) estimates degree of condensation of aromatic ring structure based on aromatic out-of-plane region; larger = higher degree of condensation a if present, it is not taken into account in calculations. table 5: semi-quantitative ftir data. ch2/ch3 al/ox ar1 ar2 car1 car2 980-391-1fc 2.08 0.29 0.06 0.44 0.017 0.13 980-391-2fc 2.58 0.34 0.05 0.26 0.017 0.09 980-391-3fc 2.07 0.30 0.06 0.38 0.018 0.12 average 2.24 0.31 0.06 0.36 0.017 0.11 980-391-2comp 2.66 0.37 0.05 0.23 0.018 0.09 980-391-3comp 2.52 0.41 0.05 0.36 0.019 0.11 980-391-4comp 2.63 0.32 0.06 0.50 0.019 0.16 average 2.60 0.37 0.05 0.33 0.019 0.12 note: fc– fossilized cuticle; comp – compression geologia croatica 65/3geologia croatica 372 from medullosalean compression foliage have larger ch2/ ch3 ratios (e.g. zodrow & mastalerz, 2007, figs. 8 and 9 compared with fig. 7) which are presently being investigated (unpublished research notes, 2012). another small difference is seen in the al/ox ratios, tab. 5, with fossilized-cuticles having smaller values (average 0.31) vs compressions (0.37), indicating a larger, relative to aliphatic hydrogen, contribution of carboxyl/carbonyl groups in the cuticle. a large element-oxygen content in the compression suggests significant portions of oxygen in compounds, other than carboxyl/carbonyl (for example in hydroxyl oh ho). the major pyrolysates (and their relative abundances) are strikingly similar (fig. 4). both fossilized-cuticles and compressions show an n-alkene/n-alkane series up to c23. the n-aliphatic hydrocarbon series is indicative of the presence of resistant cuticle hydrocarbon polymers that have been observed by edwards et al. (1997), or collinson et al. (1998). the abundant aromatic pyrolysates, those being c0-c3 alkylbenzenes and c0-c2 alkylphenols, are most probably markers of matured lignin components (see logan & thomas, 1987). these pyrolytic chemical features were also observed by edwards et al. (1997; and references there in) who performed analytical pyrolysis of the outer cortical tissue in lower devononian psilophyton dawsonii. comparison of elemental percentages shows a slightly lower carbon and hydrogen content in the compression (tab. 2), though sulfur is high and is regarded as being of dominantly pyritic origin, which is supported by observed submicron framboidal pyrite on some cushions. disregarding the sulfur, oxygen by subtraction is ca. 25% for the fossilized-cuticle and 28% for the compression. in comparison with the bituminous coal from the same coal seam the roof rocks of which entombed l. dawsonii, we note that the coalcarbon content is significantly higher hydrogen is slightly higher, whereas the nitrogen content is lower. in conclusion, it is suggested that the reversal of the ch2/ch3 ratios from the bark of l. dawsonii signals kinship with the bark of lepidodendron (and psaronius) that is a major maceral constituent in chinese permian coal (querol et al., 2001). the argument is based on sun’s (2005) work who described that bark, using transmitted-light ftir microspectroscopy, as generally being highly aliphatic figure 4: flash pygc/ms chromatograms of lepidodendron dawsonii. a) fossilized-cuticle. b) compression. peaks are annotated with appropriate chemical structures. n-alkene/n-alkane doublets (note: early eluting pairs have extensive overlap) numbered according to the appropriate carbon chain length. the peaks denoted as * are other c1-alkyphenols and as # are c2-alkylphenols. zodrow et al.: lepidodendron dawsonii: functional groups and pyrolysates of compression and fossilized-cuticle (late asturian, canada) geologia croatica 373 (long and straight hydrocarbon chains) and low (rare) in oxygenated components. though a direct comparison with our ftir data cannot be made because we use the kbr pellets, we note that the bark from l. dawsonii has shorter and more branched hydrocarbon chains. but its low content of oxygenated groups fits the description for the chinese coal maceral. py-gc/ms data support the ftir evidence of aliphatic hydrocarbon chains and gives additional evidence that the oxygen-containing molecules (i.e., observed high abundance of phenolic markers) are likely associated with matured lignin marcomolecules. overall, our results demonstrate that there are only subtle differences between the two preservation states of l. dawsonii which are, however, macroscopically manifest by the colour differences of the specimen. preservation can therefore be remarkably variable over shorter specimen distances of these large plants, depending on compaction condition after burial and taphonomy. acknowledgement we thank dr. d. keefe, dean of research and graduate studies, cape breton university, for financial support, professor dr. b.a. thomas, university of wales aberystwyth, for technical advice, research literature, and constructive review of the ms and l. dawsonii, and mr. wayne moffat, department of chemistry, university of alberta, for the elemental analyses. this paper is a contribution to the international geoscience programme (igcp project 575). references arnold, c.a. (1947): an introduction to paleonbotany.– 1st edition. mcgraw-hill, new york, 433 p. bell, w.a. (1938): fossil flora of sydney coalfield, nova scotia.– geol. surv. can. memoir, 215, ottawa, 334 p. bell, w.a. (1966): illustrations of canadian fossils: carboniferous plants of eastern canada.– geol. surv. can., ottawa, paper, 66–11, 76 p. berner, r.a. (1980): early diagenesis: a theoretical approach.– princeton university press, princeton, n.j., 241 p. cleal, c.j. & zodrow, e.l. (1989): epidermal structure of some medullosan neuropteris foliage from the middle and upper carboniferous of canada and germany.– palaeontol., 32, 837–882, pls. 97–106. cleal, c.j., oplustil, s., thomas, b.a. & tenchov, y. (2010) (for 2009): late moscovian terrestrial biotas and palaeoenvironments of variscan euramerica.– neth. j. geosci., 88, 181–278. collinson, m.e., mosle, b., finch, p., scott, a.c. & wilson, reg. (1998): the preservation of plant cuticle in the fossil record: a chemical and microscopical investigation.– anc. biomol., 2, 251–265. d’angelo, j.a., escudero, l.b., volkheimer, w. & zodrow, e.l. (2011a): chemometric analysis of functional groups in fossil remains of the dicroidium flora (cacheuta, mendoza, argentina): implications for kerogen formation.– internat. j. coal geol., 87, 97–111. d’angelo, j.a., zodrow, e.l. & mastalerz, m. (2011b): compression map, functional groups and fossilization: a chemometric approach (pennsylvanian neuropteroid foliage, canada.– internat. j. coal geol. (in press). edwards, d., ewbank, g. & abbott, g.d. (1997): flash pyrolysis of the outer cortical tissue in lower devononian psilophyton daswsonii.– bot. j. lin. soc., 124, 345–360. dimichele, w.a., phillips, t.l. & peppers, r.a. (1985): the influence of climate and depositional environment on the distribution and evolution of pennsylvanian coal swamp plants.– in: tiffne, b. (ed.): geological factors in the evolution of plants. yale university press, new haven ct, 223–256. goodarzi, f. & mcfarlane, r.a. (1991): chemistry of fresh and weathered resinites – an infrared photoacustic spectroscopic study.– internat. j. coal geol., 19, 283–301. hirmer, m. (1927): handbuch der paläobotanik. band i. thallophyta. bryophyta. pteridophyta.– r. oldenbourg, münchen, 708 p. logan, k.j. & thomas, b.a. (1987): distribution of lignin derivatives in plants.– new phytol., 105, 157–173. lyons, p.c., orem, w.h., mastalerz, m., zodrow, e.l., vieth-redemann, a. & bustin, m.r. (1995): 13c nmr, micro-ftir and fluorescence spectra, and pyrolysis-gas chromatograms of coalified foliage of late carboniferous medullosan seed ferns, nova scotia, canada: implications for coalification and chemotaxonomy.– internat. j. coal geol., 27, 227–248. painter, p.c., coleman, m.m., snyder, r.w., mahajan, o., komatsu, m. & walker, p.l. jr. (1981): low temperature air oxidation of coaking coals: fourier transform infrared studies.– applied spectroscopy, 35, 106–110. querol, x., alastuey, a., xinguo zhuang, hower, j.c., lopez-soler, a. plana, f. & rongsu zeng (2001): petrology, mineralogy, and geochemistry of the permian and triassic coals in the leping area, jiangxi province, southeast china.– internat. j. coal geol., 48, 23–45. stark, r.e. & tian, s. (2006): the cutin biopolymer matrix.– in: riederer, m., muller, c. (eds.): biology of the plant cuticle. blackwell publishing ltd., oxford, 126–144. sun, xuguang (2005): the investigation of chemical structure of coal macerals via transmitted-light ft-ir microspectroscopy.– spectrochim. acta, a 62, 557–564. thomas, b.a. (1966): the cuticle of the lepidodendroid stem.– new phyt., 65/3, 296–303. thomas, b.a. (1970): epidermal studies in the interpretation of lepidodendron species.– palaeontol., 13, pls. 29–34, 145–173. thomas, b.a. (2009): lycopsids.– in: cleal, c.j., oplustil, s., thomas, b.a. & tenchov, y. (eds.): late moscovian terrestrial biotas and palaeoenvironments of variscan eramerica. neth. j. geosci, 88/4, 181–278. van bergen, p.f., blokker, p., collinson, m.e., damsté, j.s.s. & de leeuw, j.w. (2004): structural biomacromolecules in plants: what can be learnt from the fossil record?– in: hemsley, a.r. & poolen, a. (eds.): the evolution of plant physiology. elsevier academic press, amsterdam, 133–154. wang, s.h. & griffiths, p.r. (1985): resolution enhancement of reflectance ir spectra of coals by fourier self-deconvolution. 1. c-h stretching and bending modes.– fuel, 64, 229–236. zodrow, e.l. (2002): the “medullosalean forest” at the lloyd cove seam (pennsylvanian, sydney coalfield, nova scotia, canada).– atl. geol., 38, 177–195. zodrow, e.l. & mastalerz, m. (2001): chemotaxonomy for naturally macerated tree-fern cuticles (medullosales and marattiales), carboniferous sydney and mabou sub-basins, nova scotia, canada).– internat. j. coal geol., 47, 255–275. zodrow, e.l. & mastalerz, m. (2007): functional groups in a single pteridosperm species: variability and circumscription (pennsylvanian, nova scotia, canada).–internat. j. coal geol., 70, 313–324. geologia croatica 65/3geologia croatica 374 zodrow, e.l. & mastalerz, m. (2009): a proposed origin for fossilized pennsylvanian plant cuticles by pyrite oxidation (sydney coalfield, nova scotia, canada).– bull. geosci., 84, 227–240. zodrow, e.l., d’angelo, j.a., mastalerz, m. & keefe, d. (2009): compression-cuticle relationship of seed ferns: insights from liquid-solid ftir (late palaeozoicearly mesozoic, canadaspain-argentina).– internat. j. coal geol., 79, 61–73. zodrow, e.l., d’angelo, j.a., mastalerz, m., cleal, c.j. & keefe, d. (2010): phytochemistry of the fossilized-cuticle frond macroneuropteris macrophylla (pennsylvanian seed fern, canada).– internat. j. coal geol., 84, 71–82. zodrow, e.l., mastalerz, m., orem, w.h., šimůnek, z. & bashforth, a.r. (2000): functional groups and elemental analyses of cuticular morphotypes of cordaites principalis (germar) geinitz, carboniferous maritimes basin, canada.– internat. j. coal geol., 45, 1–19. zodrow, e.l., mastalerz, m. & šimůnek, z. (2003): ftirderived characteristics of fossil gymnosperm leaf remains of cordaites principalis and cordaites borassifolius (pennsylvanian, maritimes canada and czech republic).– internat. j. coal geol., 55, 95–102. manuscript received january 21, 2012 revised manuscript accepted july 24, 2012 available online october 30, 2012 06 buljan.indd buljan et al.: engineering properties of marine sediments in mali ston bay (croatia) based on “mainland-pelješac” bridge investigations 233 �ab stra ct the complete geological characteristics of the wider area of the pelješac peninsula are presented: lithostratigraphy, structural/tectonic geology and seismotectonics. the main emphasis is on the engineering geological characteristics of the clastic sediments in mali ston bay, encountered during investigations for the building of the “mainlandpelješac” bridge project. the bridge has large proportions, as it is 2404 m in length and has 14 under-sea pylons. it required thorough and expensive in-situ and laboratory investigations which enabled the development of a detailed and reliable engineering model of the quaternary clastic sediments at the exploration site. the results clearly indicate three different engineering units which are predominantly classifi ed according to their obvious differences in consistency: unit a – very soft and soft sediment; unit b – soft to fi rm sediment and unit c – fi rm sediment. given the total sediment thickness, (locally over 100 m), the generally poor engineering properties, and the high seismic risk of the area, the substrate for the foundations is unfavourable. the units which are classifi ed according to their engineering properties also tightly correspond to the depositional environments which represent a much wider area than just the exploration site. therefore the authors presume the presence of units a, b and c in the wider area with similar geological settings to that in the proximity of the zrmanja, krka, and cetina deltas. keywords: “mainland-pelješac” bridge, sediment consistency, cpt, marine sediments, adriatic sea engineering properties of marine sediments in mali ston bay (croatia) based on “mainland-pelješac” bridge investigations � renato buljan, davor pollak and vlatko gulam geological survey, sachsova 2, 10000 zagreb, croatia; (renato.buljan@hgi-cgs.hr; davor.pollak@hgi-cgs.hr; vlatko.gulam@hgi-cgs.hr) doi: 104154/gc.2012.14 geologia croatica 65/2 233–242 13 figs. 1 tab. zagreb 2012 geologia croaticageologia croatica 1. introduction the “mainland-pelješac” bridge is designed for the southern, croatian part of the adriatic sea, to span the strait over the mali ston bay providing a crossing with a maximum span of 2,404 m, width of 24.64 m, linking kumara cove on the mainland and the surrounding area of brijesta cove on the pelješac peninsula (figure 1). it is located in a geologically and tectonically complex area, marked by seismicity, and strong winds. one of the essential requirements of the bridge design was to allow passage of marine traffi c below, which determined a bridge height of 55 m. this was an important aspect for the neighbouring port and city of neum (bosnia and herzegovina). initial research work was conducted for the purpose of the main engineering design. the foundations were examined by geophysical methods, research drilling, and laboratory testing and in-situ measurements. during 2009, additional geotechnical and engineering-geological research work was carried out at the proposed location of each pylon in the mali ston bay, and it is the results of these additional investigations that are the subject of the current work. from the coastline to a water depth of 24 m, the seabed is steep and formed of carbonate rock for the remaining length of the bridge axis, the seabed is fl at and muddy, on average at a depth of 28 m, and carbonate rock outcrops are absent. the bridge design stipulated 14 pylons in the offshore geologia croatica 65/2geologia croatica 234 area, two of which represent the central pylons, at a height of 176.15 m (radić et al., 2009). it was anticipated that the foundations of the pylons from s6 to s11 would be in a layer of hard clay, so that the bearing capacity is attained by friction against the pylon sheath. for the remaining 8 pylons the fi nal depths of the piled foundations would be in the underlying carbonate sedimentary rocks beneath the clastic sediments. the main aim of this paper is to present the engineering geological characteristics of very thick quaternary sediments at the bridge location and wider region, which haven’t been previously studied to this extent or from this point of view. some major relationships between the engineering properties of the sediments and their genesis (deposition environment and rate) are also presented. 2. geology of the study area the area under consideration is composed of upper cretaceous and lower eocene carbonate rocks, upper eocene fl ysch-like deposits, and quaternary sediments covering the seafl oor of the mali ston bay (figure 2) ( raić & papeš, 1980, maraschini et al., 2005, buljan & gulam, 2007, buljan et al., 2010, pollak et al., 2010). 2.1. bedrock geology the bedrock geology of the broader area is composed of platform carbonate rocks ranging in age from the middle triassic to the middle palaeogene. tectonic stress in the middle eocene resulted in variable uplift and differentiation of the carbonate platform. gradually, palaeogeographic and, in general, geological conditions favouring development and deposition of terrestrial clastic material into the remaining marine basins produced the complex system of siliciclastic fl ysch deposits. during the upper eocene and oligocene, the dinarides were formed with a geological strike sw-ne. these are still the most characteristic structural-geomorphological feature of the region. subsequent intensifi cation of tectonic movements during the neogene formed regionally extensive reverse-thrusting structures. during the pliocene, the main stress changed from sw-ne to s-n which, accompanied with alteration of the direction of compression, cau sed the ongoing destruction of pre-existing geological structures. the geological setting along the “mainland-pelješac” bridge refl ects the structural-tectonic relationships within the broader area. the structural setting formed as a result of dislocation of the adriatic plate towards the dinarides (prelogović et al., 1999). spatially, this mass is subducting beneath the dinarides (figure 2), attaining depths of 15 to 20 km beneath the study area (aljinović et al., 1984). more resistant blocks are displaced closer to the surface. the carbonate complex of the dinaric regional structural unit is thrust near the surface, over the epi-adriatic regional structural unit (formed of siliciclastic fl ysch deposits). the carbonate fault escarpment at the front of the dinaric thrust in the neighbouring area, is >400 m high. rock mass fracturing at the surface is simply the result of the spatial relationship and movement of the larger blocks at depth. the carbonate sedimentary rock complex in the area to the south of the fl ysch deposits belongs to the adriatic regional structural unit. the proposed bridge is located in this area although it can be stated that this site lies in the broader contact zone of figure 1: satellite view of the pelješac bridge location. buljan et al.: engineering properties of marine sediments in mali ston bay (croatia) based on “mainland-pelješac” bridge investigations geologia croatica 235 the aforementioned regional structural units.the direction of the recent stress is 20º–200º (prelogović et al., 2004), effectively parallel to the axis of the proposed bridge. in the recent structural setting, reverse faults are dominant. the main tectonic feature of the investigated terrain is the faulted folds, while the structures are monoclinal with a dinaric strike (nw-se) and beds dipping 20º–60º to the ne. apart from the reverse faults and thrust planes, many normal faults of diverse orientations can be also observed in the area. the considered area, (and in fact the whole ne coastal part of the adriatic sea), is still a seismically very active region in recent times (herak et al., 1996). as a result of the constant compression of area over approximately the last 40 million years, and consequent tangential, reverse-thrusting tectonic movements, the rock mass thickness has been multiplied, while the tectonic area has been considerably reduced. the carbonate complex is tectonically uplifted; thrust over the complex of siliciclastic fl ysch deposits, which as a pliable medium, had served for the tectonic transport of the brittle carbonate rock mass. in recent times, fl ysch is mostly eroded and reduced at the surface, and subducted beneath the carbonate rocks (figure 2). the carbonate complex itself, is reduced by thrusting, often at the contact between carbonate and dolomite rocks. together, this indicates the complex structural and tectonic relationships and intense tectonic and erosional activity in this area during the geological past and also in recent times which is substantiated by the registered earthquakes. 2.2. plio-quaternary sediments the main uplift with exhumation in the coastal zone of the adriatic sea occurred during the major tectogenic phase during the oligocene and miocene (korbar, 2009), whereas the fi nal form of the folded and faulted structures is the result of tectonic reactivation since the upper pliocene (bla šković, 1997). the climate in the mediterranean region was warmer and more humid during the oligocene and early miocene. therefore the processes of karstifi cation and pedogenesis of terra rossa were active in this region (lewin & woodward, 2009, mather, 2009). there was plenty of time for erosion of the emerged area and its’ subsequent karstifi cation. the lack of miocene and pliocene marine sediments indicates that the area of the mali ston bay was probably terrestrial from the neogene. in the quaternary, the surface erosion of carbonate rock complex was reinforced, brought about by exodynamics; the activity of sunshine, wind, water and ice. fluviokarstic forms develop mostly in the fi rst stages of karstifi cation in areas of intense rainfall, when discharge into the karst system exceeds its conduit system capacity (ford & williams, 2007). during processes of karstifi cation, surface streams could gradually disappear underground resulting in development of dry valleys. during the quaternary which lasted for the last 1.8 million years, various geomorphological structures were formed which still exist in the study area. this geological period is characterised by considerable climate change, marked by cool periods (glacials) interchanging with short warm periods (interglacials), and associated fl uctuation in sea level. the mediterranean sea fl uctuated between –40 and –60 m over the relatively long period of 80.000 years in the late pleistocene, (between 110.000 and 30.000 ka b.p.; lambeck & purcell, 2005). plio-quaternary sediments most often occur as a thin cover over the underlying carbonfigure 2: a simplifi ed segment of the geological map of the republic of croatia (originally at 1:500 000 scale; federal geological survey – beograd, 1980) geologia croatica 65/2geologia croatica 236 ate rocks; more rarely thicker if the proper morphological conditions have been met. at the bridge site, in the area of mali ston bay which was fi rst formed as a karst polje, various types of quaternary sediments were deposited in the form of eluvium, diluvium, aeolian, limnoglacial sediments. colluvial sediments originated at the foot of the slopes of the steep carbonate escarpments in the peripheral areas (raić & papeš, 1980, buljan & gulam, 2007, buljan et al., 2010, pollak et al., 2010). the recent formation and spatial setting of marine fi ne clastic deposits is closely related to: transport of the terrigenous material by the nearby neretva river; permanent tectonic activity causing the uplift of the south part of croatian adriatic coast; and to oscillating sea level in the mediterranean including the adriatic sea sedimentary basin during the upper pleistocene and holocene. remnants of the palaeostream of the nearby neretva river can be traced even today from its present mouth further along the adriatic sea, via the seafl oor along the pelješac peninsula and korčula island, all the way to vis island (surić et al., 2005; surić, 2009; crmarić, 2009). these deposits transgressively overlie the older and more compact succession of clastic sedimentary rocks in the present submerged karst depression of mali ston bay. sea level changes, from the peak of the würm glacial period 20,000 years ago were caused by eustatic and glacialhydro-isostatic changes due to global ice melting (lambeck & purcell, 2005). there was a sea level rise approximately 19,000 to 18,000 years ago, in accordance with a simultaneous global increase of temperature. following melting of the ice cover, the sea level rose abruptly between 17,000 and 6,000 years ago. after this accelerated rise, a period of relative stagnation of sea level has occurred in the adriatic sea during the last 6.000 years due to the reciprocal relationship between tectonic subsidence and hydro-isostatic highstand in regional sea level (pirazzoli, 2005, juračić et al., 2009, surić & juračić, 2010). sea-level lowstand during the last glacial age, along with humid climatic conditions, could have caused the restoration of fl uvial processes in the steep downstream parts of karst valleys during pluvial periods (tzedakis, 2009). erosion processes by surface streams and the incision of valleys, were intense in the kvarner area during this period (benac & juračić, 1998), and probably also in the wider area, along the entire east coast of the adriatic sea. erosion processes and terrigenous input into the sedimentary basin was reduced while simultaneous marine erosion/abrasion increased, considerable gravely alluvial fans formed along the coast causing progradation of the coastline (juračić et al., 2009). the same sedimentary conditions also predominated in the nearby mali ston bay, where due to the sea level rise in the quaternary, the process of deposition of sediments transported by torrents along the then existing gullies, together with particles eroded from higher terrain and transported by slope processes or the wind had begun. the sediments from the mouth of the neretva river, were carried by marine currents and also were deposited. this resulted in the gradual covering of the clayey sediments by clastic terrigenous particles in the central portion of the submerged karst valley and the carbonate landscape on the periphery. 3. the investigation methods the detailed investigations presented in the paper were perfor med at each of the bridge submarine pillar foundation locations in the profi le (figure 3). these included in-situ testing: core drilling, down-hole seismic profi ling, cone pene tration testing with pore pressure measurements (cptu), pocket penetrometer tests; engineering geological core examination/description; and laboratory analysis of the core samples: granulometry, atterberg limits, x-ray diffraction analysis and mechanical properties testing. entire site investigations were performed from the adopted exploration ship platform in challenging submarine conditions. additionally, both seashore zones were mapped by diver’s expert in engineering geology. the boreholes were located at the corners and in the centre of the proposed pylon locations. as the boreholes followed the geological predictions and geotechnical design requirements, the total drilled length exceeded 2900 m in 42 boreholes ranging from 12 to 112 m in depth. during core examination and description, the usual procedures for fi eld and manual determination of soil identifi cation were carried out. the manual test procedures including determination of plasticity, consistency and dry strength, followed international standards (iso, 2002). laboratory testing of soil mechanical properties were done in accordan ce with widely used standards: direct shear strength (astm, 2004), uniaxial and triaxial strength tests (bs, 1990). micropalaeontological and palynological analyses determined the fossil content of fi ve soil samples, while absolute age was determined by the means of c14 determination (pavelić, 2005). the mineralogical composition was determined by xrd analysis and carbonate content by the scheibler method (altfelder et al., 2007). the same boreholes were also used for downhole seismic profi ling in the 12 locations for a total length of 843 m. analysis of the downhole records here, included data from the average of three metre interval velocities. seven profi les with cone penetration tests were performed at 5 locations (in the centre of the pylon locations s6 to s10) with a total depth of penetration of 457 m. the profi les were done with pore pressure measurements (cptu) in accordance with draft standard (en iso, 2009) and the directives of eurocod 7 (cen, 1999). penetrations were performed by a “geomil – penetrometer 200 kn” with a maximum penetration force of 200 kn. penetration velocity was in the range of 20 ± 5 mm/s. after the measurements the sediment was classifi ed according to robertson’s method (robertson, 1990). the cone penetration resistance measurements (qc) which were continuously collected along each profi le, were then analysed. buljan et al.: engineering properties of marine sediments in mali ston bay (croatia) based on “mainland-pelješac” bridge investigations geologia croatica 237 4. results at the bridge location the sea fl oor is horizontal at a depth of around 28 metres (leder, 2004). preliminary geophysical exploration with six borehole probes indicated a surprisingly thick sediment cover on carbonate bedrock (maraschini et al., 2005). detailed investigations confi rmed that the sediment thickness at many locations exceeds 100 metres which wasn’t expected given contemporaneous geological knowledge. according to the on-site core examinations, descriptions and manual tests of sedimentary material, three engineering geological units could be distinguished. the units are regularly stratifi ed and their boundaries are almost horizontal (figure 3). these units were predominantly distinguished according to obvious differences in consistency and subordinately by their diverse mineral and grain size content and colour. according to 14c radiometric dating of the extracted organic part of the marine sediment sample, the absolute age of samples from a depth of 5.5 m below the seafl oor is 8,580 (±275) years, while sediments at 35.5 m are 17,100 (±530) years old (pavelić, 2005). these results indicate very rapid deposition during the period between 17,100–8580 years ago, of 2.08 mm per year, which slowed to a depositional rate of 0.64 mm per year during the last 8,580 years, which is in accordance with the aforementioned rate of sea-level rise in the adriatic sea. unit a – very soft and soft sediment. very soft and viscous sediment represents the fi rst 7 m (17 m in maximum) of the seabed profi le. at depths of 7–8 and 16 m there are frequent organic lenses. organic clays and silts occasionally contain fi brous peat material. soft grey sediments in this unit have very low – low dry strength, and are high (ch to mh), or rarely low plastic clays/silts according to laboratory testing (figure 4). freshwater and marine bivalves and gastropod fragments are frequent, occasionally forming up to 20% of the content. the most recent sediments of the unit are strongly infl uenced by the neretva river delta which is only 12.5 km to the nw. older deposits (>8–9 ka) represented by those deeper than about 5m, suffer increasingly from the impact of the brackish water. later on above 5m depth in this unit, freshwater and marine environments irregularly interchange. carbonate minerals are dominant over smectite and vermiculite. the total thickness of unit a is generally 28m, increasing locally to a maximum of 38m. unit b – soft to fi rm sediment. mainly grey to brownish grey highly plastic clay and silt (ch to mh). the manual test indicated medium to low dry strength. there are also segments with material of low plasticity (cl to ml) (figure 5). this unit is also characterized by sandy intrabeds, and in the lower part, with rounded calcite concretions up to several figure 3: schematic engineering geological cross-section with simplifi ed bridge construction. vertical scale exaggeration is x10. geologia croatica 65/2geologia croatica 238 centimeteres in size. marine bivalves and gastropods are usually randomly scattered and just occasionally enriched in some lenses. sedimentation of this unit occurred in a predominantly shallow low energy marine environment. carbonate minerals are predominant, but the calcite content is lower toward the base of the unit. unit b varies in thickness from 25–38 m and has a gradational boundary with unit a. unit c – fi rm sediment. highly plastic clay (ch), reddish brown in colour with calcite concretions. the manual test was uniform and indicated a high dry strength for the clay material. rounded calcite concretions from one to several centimetres in diameter are frequent and in some locations constitute >10 % of the sediment mass (figure 6). several metres above the carbonate bedrock (1–5 m) the soil is a mixture of the same material and limestone detritus. the limestone clasts are irregular, subangular and up to several centimetres in size. their proportion decreases upwards from the contact with the limestone bedrock. in unit c there are also some rare intrabeds (3 m thick) of sandy or even gravelly material. the upper boundary with unit b on top, and also the lower one with the limestone bedrock, are usually very sharp and easily detectable. in this unit quartz is dominant over smectite. the foraminiferal assemblage, mineral composition and absence of pollen are clear indicators of a deeper and open marine depositional environment (pavelić, 2005). the total thickness of unit c, as a consequence of the palaeomorphology, is variable, with a maximum of 40 metres (figure 3). the design of the pylons which remain in the sedimentary material was based solely on the much better engineering properties of unit c. therefore, additional laboratory testing of its mechanical properties was performed (table 1). the cohesion and internal friction parameters of direct shear and triaxial drained tests are comparable. the uniaxial strength of the soil material within unit c is 214 kpa on average, with a high standard deviation of 110 kpa. unit d – carbonate rock mass. the bridge abutments and adjacent pylons are located at the karstifi ed carbonate figure 4: unit a – plasticity chart (164 samples), granulometry histogram (162 samples) and characteristic borehole core in 1m boxes. figure 5: unit b – plasticity chart (161 samples), granulometry histogram (170 samples) and characteristic borehole core in 1m boxes. figure 6: unit c – plasticity chart (231 samples), granulometric histogram (252 samples) and characteristic borehole core in 1m boxes. buljan et al.: engineering properties of marine sediments in mali ston bay (croatia) based on “mainland-pelješac” bridge investigations geologia croatica 239 shore (figure 3). this carbonate rock mass also represents the bedrock of the described sediments. upper cretaceous and lower eocene limestones are locally recrystallized, dolomitized, and are frequently very jointed. the karstifi cation of these carbonates is evident, since there are many caverns and wide discontinuities with corrosion marks. such diagenetic and post-diagenetic processes are the consequence of the intensive tectonics in the geological history. mechanical properties of rock material within unit d were determined by uniaxial compressive strength and young’s modulus. the uniaxial compressive strength test, as one of the most important indicators of rock quality, was performed on 77 samples obtained by exploration drilling. the results show a large distribution where the minimum noted value was 28 mpa while the maximum was 227 mpa (figure 7). young’s modulus has also shown a large spread in the results obtained, where the minimum value was 3 gpa and the maximum was 61 gpa (figure 8). in order to determine the mechanical characteristics of the rock mass in unit d, the gsi categorization was performed using data gathered by the engineering geological mapping of the coastal area of mali ston bay, together with data obtained from core drilling. this indicator, also, showed a large spread where the minimal gsi value recorded in the base of pillar s10 was 27, and the maximum in the base of pillars s15 and s16 was 80. such a wide range of gsi can be primarily attributed to diffi cult drilling conditions which precluded the collection of high-quality core material. 5. discussion here, core sample analysis and the most important laboratory results are compared to in-situ tests and measurements. according to several authors (rominger & rutledge, 1952; means & parcher, 1963) the liquidity index (il) gives reliable information about the degree of consolidation of clayey sediments. the same index was calculated for the tested materials and is presented in figure 9. since lower il values indicate a higher degree of consolidation, the trend of increasing consolidation with sample depth is obvious. it is also clear that unit a in general has il values closer to 1, which is the liquid limit, while materials in units b and especially c have il values much closer to zero. these il values are also presented statistically for each unit (figure 10). as expected, the upper segment of unit a is lightly consolidated, but most of the tested material in unit a (average il=0.23) and b (average il=0.18) can be regarded as highly consolidated. the much higher consolidation rate of highly plastic clayey material (unit c) which has il values below zero (average il=–0.05) in comparison to the soils with carbonate content is also clearly observed. in order to numerically express the consistency of the material, the consistency index (ic) is presented (figure 11). in accordance to the il values of the samples, the ic indicates mainly fi rm consistency of the material in units a (average ic=0.71) and b (average ic=0.87). the average ic values of unit c are, however around 1 (ic=1.01) indicating that the sedimentary material is between stiff and very stiff in its consistency. both, figs. 10 & 11 display much wider oscillations of il and ic values in units a and b in comparison to unit c. in contrast, measured cone penetration (cpt) resistance values (qc) are very uniform for unit a (figure 12). in addition, the upper seven metres (rarely up to 20 m) of unit a are without any penetration resistance indicating very soft, even viscous media. the average values of qc confi rm the experience engineering geologists had during core examination in explored profi le – the need to divide sediments into three units. although units b and c have high oscillations in qc values, the averages clearly indicate three totally different sediment mass properties, with cpt measurements of: a – qc=0.93 mpa, b – qc=2.12 mpa, c – qc=3.81 mpa (figure 12). figure 7: unit d – distribution of uniaxial compressive strength (77 samples). figure 8: unit d – distribution of young's modulus (77 samples). table 1: the mechanical properties of samples from unit c. laboratory test c / kpa f / ° no. of samples mean st. dev. mean st. dev. "direct shear (cd)" 43.8 17.7 18.8 2.1 13 triaxial strength (cu) 37.2 21.3 20.8 2.2 5 triaxial strength (uu) 1395 48.7 – – 26 geologia croatica 65/2geologia croatica 240 figure 13 displays the correlation between the consistency indexes of samples and cone penetration resistance at the same overburden depth. the chart displays certain dependence of the two parameters when sediment has ic<0.75, or has a fi rm or soft consistency. however, according to the laboratory and in-situ measurements, the consistency index in stiff and very stiff material cannot indicate the order of magnitude of cone penetration resistance. downhole seismic profi les have easily and precisely determined boundaries between the bedrock and overlying sediments, but couldn’t differentiate sedimentary units since the measured primary wave velocities for the whole complex are on average between 1550 and 1560 m/s. seismic parameters such as seismic intensity imax=9.2º mcs, seismic amplitude of earthquake mmax=6.5 by richter, soil acceleration (horizontal acceleration) at the level of the solid rock particle amax=0.41 g have been calculated for the bridge site (prelogović et al., 2004). tectonic activity of the area and a very signifi cant seismicity will have a very adverse impact on the bridge foundations. the regional geology, together with the specifi c local conditions which required undersea investigations enables conclusions to be drawn about the engineering geological properties, not just at the bridge site but also for a much wider area. the afore mentioned environments, and therefore engineering properties are expected to be very similar for other areas in the proximity of river deltas along the dalmatian adriatic coast (zrmanja, krka and cetina) which are not yet explored in terms of engineering properties. figure 9: the liquidity index values (il) of 578 tested samples in relation to sampling depth. figure 10: the average (circles) and standard deviation (red lines) values of the liquidity index (il) in sedimentary material of the units (578 samples). dashed lines represent the boundaries between consolidation levels according to means & parcher (1963). figure 11: the average (circles) and standard deviation (red lines) of consistency index (ic) in soil material of the units (551 samples). figure 12: the average (circles) and standard deviation (red lines) of all cone resistance measurements in particular units. based on 7 profi les with a total depth of 457 m. figure 13: comparison of the consistency index (ic) and cone penetration resistance (qc) in particular engineering geological units. buljan et al.: engineering properties of marine sediments in mali ston bay (croatia) based on “mainland-pelješac” bridge investigations geologia croatica 241 6. conclusions the location, geological situation and size of the bridge, required a demanding programme of exploration. from the presented data it is clear that the sediment thickness in the central locations of the bridge (pillars s5-s11) exceeds 75 m and reaches up to 100 m. therefore, the depth to the consolidated rock mass at several locations is about 130m below sea level. also, the presented data indicate that the upper 60 metres of the sediment profi le generally has very poor engineering conditions. in addition, the geotechnical design should anticipate differential settling as several pylons are founded in strong carbonate rock while others are anchored in stiff plastic sedimentary material. this, together with the bridge span, and seismicity of the area, leads to the conclusion that construction of the bridge will be very challenging, expensive and risky. the engineering properties of the different sediment units are described by means of consistency which, in this case, together with plasticity, turned out to be a very indicative and valuable parameter. additionally, consistency and plasticity can be detected by very simple manual tests, which enabled early subdivision of the soil material into three units (a, b and c). the exploration works also documented sediments with several characteristic depositional environments, characterized by specifi c engineering properties in particular those related to overburden depth: unit a – alternately marine and brackish environment with low overburden – very soft to soft sediment; unit b – shallow marine with low and rare higher energy periods, with overburden of several tens of metres – soft to fi rm sediment; unit c – deeper and very low energy marine deposition environment, with overburden of more tens of metres up to hundred metres – fi rm sediment. variations on the physical and mechanical properties within units a and b are frequent and considerable, due to variation in composition and consolidation rate which also followed depositional environment and later sedimentation. namely, due to variations in sea level and energy, the composition, mineral content, and grain size also vary accordingly. references altfelder, s., birke, m., dohrmann, r., hilse, h., jenn, f., kaufhold, s., knödel, k., nitsche, c., schmidt, k.r. & thiem, a. (2007): methods for characterizing the geochemical and microbiological conditions.– environ. geol., 5, 749–940. astm d 3080 – 04 (2004): standard test method for direct shear test of soils under consolidated drained conditions. aljinović, b., blašković, i., cvijanović, d., prelogović, e., skoko, d. & brdarević, n. (1984): correlation of geophisical, geological and seizmological date in the coastal part of yugoslavia.– bolletino di oceanologia teoretica ed applicata, ii/2, trieste, 77–90. benac, č. & juračić, m. (1998): geomorphological indicators of sea level changes during upper pleistocene (würm) and holocene in the kvarner region (ne adriatic sea).– acta geogr. croat., 33, 27–45. blašković, i. (1997): the helikoidal fault systems of vinodol (croatia) and their genesis.– geol. croat., 50, 49–56, zagreb. bs 1377-8 (1990): methods of test for soils for civil engineering purpose. part 7 and 8. buljan, r. & gulam, v. (2007): most kopno – pelješac s pristupnim cestama. inženjerskogeološko izvješće za trasu i objekte [most mainland – pelješac with access roads. engineering geological report for route and objects – in croatian].– hrvatski geološki institut, zagreb. buljan, r., pollak, d., gulam, v., benac, č. & podolszki, l. (2010): most "kopno-pelješac" inženjerskogeološki izvještaj za stupna mjesta, knjiga i [most mainland – pelješac engineering geological report for the tower locations, volume i – in croatian].– arhiv hgi, arhiv hrvatske ceste. buljan, r., gulam, v. & pollak, d. (2010): the kopno-pelješac bridge – the engineering geological characterisics.– in: horvat, m. (ed.): abstracts book, 4. croatian geological congres, šibenik 14–15.10.2010., croatian geological survey, zagreb, 161–162. cen, european committee for standardization (1999): eurocode 7: geotechnical design – part 3: design assisted by fi eld testing, env 1997-3: 1999. crmarić, r. (2009): geološko kartiranje podmorja – primjer područja otoka lastova, mljeta i korčule [geological mapping of seabed – example from the area between the islands lastovo, mljet and korčula – in croatian].– unpubl. mcs. theses, faculty of science, university zagreb, 88 p. en iso 22476-1 (2009): ground investigation and testing – field testing – part 1: electrical cone and piezocone penetration tests. ford, d. & williams, p. (2007): karst hydrogeology and geomorphology.– john wiley & sons ltd., chichester, 562 p. herak, ma., herak, d. & markušić, s. (1996): revision of the earthquake catalogue and seismicity of croatia, 1902–1992.– terra nova, 8, 86–94. iso 14688-1 (2002): international standard (2002): geotechnical investigation and testing – identifi cation and classifi cation of soil, part 1: identifi cation and description. juračić, m., benac, č., pikelj, k. & ilić, s. (2009): comparison of the vulnerability of limestone (karst) and siliciclastic coasts (exam ple from the kvarner area, ne adriatic, croatia).– geomorphology, 107 (1–2), 90–99. korbar, t. (2009): orogenic evolution of the external dinarides in the ne adriatic region: a model constrained by tectonostratigraphy of upper cretaceous to paleogene carbonates.– earth-science reviews 96, 296–312. lambeck, k. & purcell, a. (2005): sea-level change in the mediterranean sea since the lgm: model predictions for tectonically stable areas.– quaternary sci. rev., 24, 1969–1988. leder, n. (2004): prethodni istraživački radovi za potrebe projekta “most kopno – poluotok pelješac”, knjige 1–4 [previous research works for the purposes of bridge mainland – pelješac, volume 1–4 – in croatian].– hrvatski hidrografski institut, split. lewin, j. & woodward, j. (2009): karst geomorphology and environmental change.– in: woodward, j.c. (ed.): the physical geography of the mediterranean. oxford university press, oxford, 287–318. lunne, t., robertson, p.k. & powell, j.j.m. (1997): cone penetration testing in geotechnical practice.– blackie academic & professional, 312 p. maraschini, m., pedemonte, m. & paoletti, l. (2005): pelješac bridge location, adriatic sea, final report, geotechnical investigation.– unpubl. report, crosco, d’appolonia 04-900-h4. means, w.e. & parcher, j.v. (1963): physical properties of soils.– charles e. merrill publ. co.,columbus, ohio, 476 p. mather, a.e. (2009): tectonic setting and landscape development, in j. c. woodward (ed.): the physical geography of the mediterranean.– oxford university press, oxford, 5–32. geologia croatica 65/2geologia croatica 242 pavelić, d. (2005): stratigrafska determinacija naslaga jadranskog pod morja u okolici pelješca [stratigraphic determination adriatic sea bed sediments in the vicinity of pelješac – in croatian].– rudar sko -geološko-naftni fakultet, zagreb, unpubl. report 13-477/ 1-60/05. pirazzoli, p.a. (2005): a review of possible eustatic, isostatic and tectonic contributions in eight late-holocene sea-level histories from the mediterranean area.– quaternary sci. rev., 24, 1989–2001. pollak, d., gulam, v., bostjančić, i., buljan, r. & podolszki, l. (2010): most “kopno-pelješac” inženjerskogeološki značajke područja stupnih mjesta, knjiga ii [bridge mainland – pelješac engineering geological characteristics of the area beneath towers, book ii – in croatian].– arhiv hgi, arhiv hrvatske ceste. unpubl. report. prelogović, e., kuk, v., buljan, r., tomljanović, b. & skoko, d. (1999): recent tectonic movements and earthquakes in croatia.– proc. 2nd intern. symp., geodymanics of the alpsadria area by means of terrestrial and satellite methods, dubrovnik, sept. 28 – oct. 2, 1998, (eolić, k. and moritz, h. (eds.); zagreb and graz, 255–260. prelogović, e., pribičevič, b., ivković, ž., dragičević, i., buljan, r. & tomljenović, b. (2004): recent structural fabric of the dinarides and tectonically active zones important for petroleum-geological exploration in croatia.– nafta, 55/4, zagreb. 155–161. radić, j., šavor, z., hrelja, g. & mujkanić, n. (2009): pelješac bridge.– građevinar, 61, zagreb, 801–814. raić, v. & papeš, j. (1980): osnovna geološka karta sfrj 1:100 000, list ston i popratni tumač karte [basic geological map of sfry 1:100 000, ston sheet – in croatian].– geoinženjering-sarajevo, geološki zavod-zagreb, savezni geološki zavod, beograd, 39 p. robertson p.k. (1990): soil classifi cation using the cone penetration test.– can. geotech. j., 27, 151–157. rominger, j.f. & rutledge, p.c. (1952): use of soil mechanics data in correlation and interpretation of lake agassiz sediments.– j. geol., 60, 160–180. smith, g. n., (1990): elements of soil mechanics.– blackwell scientifi c publications, 509 p. surić, m., juračić, m., horvatinčić, n. & krajcar bonić, i. (2005): late pleistocene-holocene sea level rise and pattern of coastal karst inundation: records from submerged speleothems along the eastern adriatic coast (croatia).– mar. geol., 214, 163–175. surić, m. (2009): reconstructing sea-level on the eastern adriatic sea (croatia) – an overview.– geoadria, 14/2, zadar (2009), 181–199. surić, m. & juračić, m. (2010): late pleistocene – holocene environmental changes – records from submerged speleothems along the eastern adriatic coast (croatia).– geol. croat., 63/2, 155–169. tzedakis, p.c. (2009): cenozoic climate and vegetation change, in j. c. woodward (ed.): the physical geography of the mediterranean.– oxford university press, oxford, 89–137. manuscript received november 14, 2011 revised manuscript accepted january 28, 2012 available online june 29, 2012 schlagintweit.indd 1. introduction the upper jurassic to lower cretaceous shallow water platform carbonates of the northern calcareous alps (plassen formation, “lärchberg formation”) and the resedimented deposits of the latter within basinal series (barmstein limestone, tressenstein limestone) are currently under re-investigation (schlagintweit et al., 2003; gawlick et al., 2005). this shallow water development is directly linked to tectonic activity in the western tethyan domain causing early nappe formations (gawlick et al., 1999; frisch & gawlick, 2003). already in the middle jurassic, the geodynamic and sedimentological framework was mainly governed by the closure of parts of the tethyan ocean leading to the first thrust nappes and the formation of a rise-andbasin pattern (e.g. gawlick et al., 1999). starting in the southern parts of the northern calcareous alps, the compressional tectonic regime governed uplift processes producing shallowing-upwards successions from basinal to external and finally internal carbonate platform deposits. in the same way as there were different neogyroporella? gawlicki n.sp., a new dasycladale from the upper jurassic–lower cretaceous “lärchberg formation” of the northern calcareous alps, austria felix schlagintweit basins with cherty sediments (“radiolarite basins”), the new results show that there was not only one, but several independent areas with shallow water carbonates within the former deeper-marine area (e.g. kügler et al., 2003 – fig. 3; frisch & gawlick, 2003; gawlick & frisch, 2003 – for further details, and unpubl. data). current research should help to increase the precision of existing palaeogeographic and geodynamic interpretations and models. however, there is still a lack of knowledge of the micropalaeontological composition of these platform carbonates, in contrast to the comparably good data base of the alpine triassic. in the course of recent biostratigraphic and microfacies analyses of the alpine “upper jurassic” platform carbonates, a dasycladacean alga, that has already been figured several times from the northern calcareous alps since the early 1990’s as macroporella praturloni dragastan, has been recognized as a new species and is established as neogyroporella? gawlicki n.sp. 2. geological setting in the salzburg calcareous alps, near the german– austrian border, there are several isolated occurrences of shallow water limestones known as the “lärchberg formation” (ferneck, 1962), currently a non-formalized unit. for a long time, these carbonates have been assigned to the triassic, e.g. dachstein limestone, and it was ferneck (1962) who first recognized their upper jurassic–lower cretaceous age. he proposed the subdivision of the “lärchberg formation” into two parts: a clastic basal complex (lofer beds or l. member) and the lerchkogel limestone. these lithologies have been referred to in the works of ferneck (1962), darga & schlagintweit (1991) and dya (1992). another upper jurassic carbonate platform evolutionary series in the northern calcareous alps is known as the plassen formation, with the typelocality mount plassen near hallstatt in the austrian salzkammergut (e.g. tollmann, 1976). in contrast to the latter, the “lärchberg formation” partly shows a terrigenous influx unknown from the former. however, detailed discussions on their possible correlation are geologia croatica 58/2 103–117 3 figs. 3 tabs. 3 pls. zagreb 2005 key words: calcareous algae (dasycladales), taxonomy, upper jurassic, lower cretaceous, “lärchberg formation”, northern calcareous alps, austria. university leoben, institute for geosciences, prospektion and applied sedimentology, peter-tunner-str. 5, a-8700 leoben, austria; e-mail: ef.schlagintweit@t-online.de. abstract a new dasycladale (calcareous green alga) is described as neogyroporella? gawlicki n.sp. from the upper jurassic–lower cretaceous “lärchberg formation” of the northern calcareous alps, austria. it is distinguished from the type-species neogyroporella elegans yabe & toyama (upper jurassic of japan; currently the only representative of the genus), by its distinctly smaller dimensions and a higher number of laterals. the generic attribution of the new taxon is discussed, including similarities/differences to allied genera, especially humiella sokač & velić. neogyroporella? gawlicki n.sp. is so far only known from the northern calcareous alps. in addition, some other dasycladales accompanying neogyroporella? gawlicki n.sp. are also illustrated. 104 geologia croatica 58/2 beyond the scope of this paper. the marly limestones of the “lärchberg formation” are characterized by a rich assemblage of dasycladales together with “stromatoporoids”, benthic foraminifera and cyanophycean algae. in some parts, representatives of the protohalimedacean alga pinnatiporidium (sensu dragastan et al., 2002) are dominant and can be termed pinnatiporidium wackestones to floatstones. these lithologies yielded the new dasycladale neogyroporella? gawlicki n.sp. detected at the dietrichshorn and litzelkogel (fig. 1). the marly limestones containing the new alga outcrop near the summit of the litzelkogel (1625 m a.s.l.), which forms a plateau-like mountain, together with the gerhardstein (1541 m a.s.l. – fig. 2). due to sporadic outcrops and vegetation as well as steep flanks bordering the plateau, a lithological profile cannot be provided. according to dya (1992), the “lärchberg formation” of the litzelkogel-gerhardstein has a thickness of about 250 m. neogyroporella? gawlicki n.sp. was figured by dya (1992 – profile 11) as macroporella? praturloni dragastan (see synonymy below) from the northern part of the gerhardstein–litzelkogel plateau. detailed sampling carried out in recent times, has shown that neogyroporella? gawlicki n.sp. is missing at the gerhardstein. here, the youngest sediments exposed can be attributed to the uppermost kimmeridgian or lowermost tithonian due to subaerial exposure (unpublished data). at the dietrichshorn (1542 m a.s.l.), located about 11 km northwest of the litzelkogel, neogyroporella? gawlicki n.sp. was also figured by darga & schlagintweit (1991) as macroporella? praturloni dragastan (see synonymy below) from marly limestones that have been attributed to the lofer member, the clastic influenced part of the “lärchberg formation”. for further details see darga & schlagintweit (1991). 3. systematics order dasycladales tribe salpingoporelleae genus neogyroporella yabe & toyama, 1949 remarks: as will be discussed below, we tentatively assign our specimens to the genus neogyroporella yabe & toyama. the genus neogyroporella with the type-species neogyroporella elegans has been established by yabe & toyama (1949), from the upper jurassic torinosu limestone of the sakawa basin, japan. the age of the torinosu limestone, previously referred to the oxfordian–tithonian interval, has more recently been precisely dated as tithonian–berriasian (e.g. ohga & iryu, 2003; shiraishi & kano, 2004). therefore the exact stratigraphic position of neogyroporella elegans is not known in detail. neofig. 1 generalized geographic sketch map of the localities where the new dasycladale neogyroporella? gawlicki n.sp. has been detected. 105schlagintweit: neogyroporella? gawlicki n.sp., a new dasycladale... gyroporella elegans has not been recorded again since 1949 from its type-locality nor from any other occurrence. the original figures, however, have been reillustrated by johnson (1964), bassoullet et al. (1978) and deloffre (1988). bassoullet et al. (1978) regard the “weakly known alga” as well characterized by the shape and arrangement of the primaries. the latter are of the cladosporous type (barattolo, 1991 – p. 523). in his classification of the dasycladales the genus neogyroporella has been included in the subtribus salpingoporellinae bassoullet et al. 1978 by deloffre (1988), characterized by phloiophorous first order laterals. the primaries can also be compared with elongated vesiculiferous laterals comparable for example with the triassic gyroporella ampleforata pia (see pl. ii, fig. 5). ott & flaviani (1983 – p. 25) state that on two original figures of neogyroporella elegans, the existence of a corona at the proximal part of the laterals could be assumed. yabe & toyama (1949 – p. 162) just indicate that the calcareous crust “more or less thickens at the very basal part” of the laterals. anyway, the existence of a corona structure in neogyroporella has not so far been observed. it should be noted that the presence/absence of such proximal modifications of the laterals are regarded as generic characteristics. for example clypeina-type dasycladales with a short basal portion below the junction point were removed from clypeina and refered to the genus hamulusella elliott by barattolo (1998). similar structures were also illustrated by de castro (1997 – pl. 20, fig. 1) from clypeina sulcata (alth) and called “small lower protuberance (lp)”. a second species of neogyroporella has been described as neogyroporella servaisi by michaud (1988) from the maastrichtian of mexico. due to the existence of pedunculated primaries it has been transferred to the genus morelletpora by granier et al. (1991). barattolo (2002 – p. 25), however, prefers to keep the species in the genus neogyroporella although with some doubts. in revision of the jurassic– cretaceous dasycladales by granier & deloffre (1993), neogyroporella elegans has been treated as a valid taxon and the only species of the genus neogyroporella. although never discussed previously, another genus very similar to neogyroporella is humiella sokač & velić (1981), with the type-species humiella catenaeformis (radoičić) from the neocomian of southern herzegovina. in fact, representatives of humiella are characterized by alternating fertile laterals (ampullae), closed at the tips which are of variable shape (mostly bulbous). in both the original description, and others, “a thin corticular envelope enwrapping the soft parts of the plant” has been proposed by sokač & velić (1981 – p. 104) as the main generic characteristic. this feature has also been remarked for neogyroporella by yabe & toyama (1949 – “surface is covered by a thin calcareous crust”). later, the main characteristic of humiella was said to be represented by tiny pores or indentations in the calcareous wall of the laterals with the main axis corresponding to sterile laterals (masse et al., 1984; sokač, 1987). in fact, these “pores” or indentations (= “kleine zähnchen” – ott & flaviani, 1983) obviously only seldom cut through the whole wall and can therefore be termed “blind pores” as described from the genus drobnella barattolo, 1998 (chlorophyta or charophyta). the existence of such blind pores or real pores, however, is not clearly observed in the specimens from the northern calcareous alps. due to strong recrystallization the boundary between adjafig. 2 general position of the sample localities with neogyroporella? gawlicki n.sp. at the litzelkogel type locality. the sample a-190 contains the holotype. 106 geologia croatica 58/2 cent calcite crystals may suggest a finely perforated wall (diagenetic origin!). this uncertainty has been the reason to only tentatively refer these specimens to the genus neogyroporella. however, if a re-investigation of the type-material of neogyroporella elegans yabe & toyama shows both types of pores in the calcareous walls, as could perhaps be assumed in, for example, fig. 5 from yabe & toyama (1949) and any kind of corona structure is absent, the genus humiella would become very close to neogyroporella or perhaps even a synonym of the former. finally, it should be mentioned that the genus humiella has been included in the tribe clypeineae with “verticilles espacés” by deloffre (1988). the genus humiella, however, includes both species with well spaced-out verticals, such as humiella sardiniensis (ott & flaviani), or forms with closely packed touching laterals, such as humiella japodica recently described by sokač (2001) from the lower jurassic of croatia. for the clypeina species with slightly touching whorls (“overlapping whorls”), the genus similiclypeina has been established by bucur (1993). last but not least, the systematic framework becomes more complex as the genus humiella sokač & velić has been regarded as a synonym of sarfatiella conrad & peybernes by conrad (1982). sarfatiella, however, is treated as a synonym of holosporella pia by bassoullet (1987) and by granier & deloffre (1993). the whole brief discussion of current taxonomic incongruencies is not pursued further here; it is just mentioned for completeness, but it also expresses the uncertainties we have in the systematic attribution of these specimens (see also table 1). neogyroporella? gawlicki n.sp. pl. i, figs. 1–9; pl. ii, figs. 1–2, 4; pl. iii, figs. 2–5 1991 “macroporella” praturloni dragastan – darga & schlagintweit: p. 209; pl. 3, figs. 2–3 1991 “macroporella” praturloni dragastan – schlagintweit: pl. 1, fig. 7 1992 “macroporella” praturloni dragastan – dya: p. 83; pl. 7, fig. 15; pl. 8, figs. 4–5, 8 origin of the name: dedicated to prof. h.-j. gawlick, university of leoben, in recognition of his stimulating new concepts and ideas concerning the geodynamic evolution of the alpine jurassic. type-locality: litzelkogel, topographic map of austria ök 92 sheet lofer, marly limestones cropping out in the area of the summit (fig. 2). the location of the summit of the litzelkogel is 12º46’ geographic longitude and 47º38’ geographic latitude. type strata: light brownish, marly limestones of the “lärchberg formation”, partly displaying a siliciclastic influx. the dasycladales include salpingoporella gr. pygmaea (gümbel) (common), salpingoporella cf. istriana (gušić) (rare; pl. iii, fig. 1), chinianella? sp. (rare; pl. iii, fig. 10), montenegrella florifera bernier (pl. iii, fig. 6), neogyroporella? gawlicki n.sp., with protohalimedacean algae (genus pinnatiporidium) and benthic foraminifera with comaliamma? cf. gediki (tasli), rheopax sp. and protopeneroplis ultragranulata (gorbatchik) (pl. iii, fig. 7). in addition, remains of gastropods, stromatoporoids, oncoids and nodules formed by lithocodium aggregatum elliott are present. at the dietrichshorn locality, neogyroporella? gawlicki n.sp. is associated with clypeina aff. parasolkani farinacci & radoičić (pl. ii, fig. 6), clypeina catinula carozzi (pl. ii, fig. 13), clypeina aff. isabellae masse, bucur, virgone & dalmasso (pl. ii, fig. 11), cylindroporella? sp. (pl. ii, fig. 9), zergabriella embergeri (bouroullec & deloffre) (pl. ii, fig. 7), salpingoporella annulata carozzi, rajkaella bartheli (bernier) and deloffrella quercifoliipora granier & michaud (pl. ii, figs. 8, 10, 12) and the benthic foraminifera anchispirocyclina lusitanica (egger) and kastamonina abanica sirel (pl. iii, figs. 8–9). at both the dietrichshorn and litzelkogel localities, the dasycladalean remains typically show micritic envelopes of presumably cyanophycean origin. material: one thin-section containing about 30 specimens from mount dietrichshorn and several thin-sections each with 2–5 specimens from mt. litzelkogel. genus neogyroporella humiella clypeina similclypeina actinoporella laterals in mutual contact in mutual contact spaced-out in mutual contact spaced-out or spaced-out corona ? (1) missing missing (1) missing present structure blind pores ? present maybe present (2) missing missing (sterile branches) table 1 main characteristics of neogyroporella and allied dasycladale genera. legend: (1): see remarks in the text, (2): as shown in some clypeina species (e.g. radoičić, 1969). 107schlagintweit: neogyroporella? gawlicki n.sp., a new dasycladale... holotype: oblique-tangential section figured on pl. i, fig. 5, thin section labelled a–190 (exact location see fig. 2). the material from the litzelkogel is stored at the “institut für geowissenschaften, universität leoben”. isotypes are represented by different sections shown in pls. i–iii. diagnosis: thallus euspondyl, cylindrical with a comparable small main axis and numerous elongated, gently broadening laterals with swollen endings. the laterals, closed at tips, are arranged more or less perpendicular or slightly inclined to the axis. the microstructure of the individual calcified sheaths enclosing the laterals has a fibrous appearance. the whorls are close-set with alternating laterals touching those from adjacent whorls. reproductive organs presumably cladosporous. description: thallus simple and cylindrical. the axial cavity is comparatively small, most frequently comprising 27–30% of the total diameter. the simple, undivided and elongated laterals communicate with the axial cavity by means of narrow connecting pores that broaden gently, then swell into sphere-like distally closed ends. the arrangement of laterals in consecutive whorls is alternating. the main axis and the laterals are each covered with their own thin calcareous envelope. due to secondary calcification, the laterals are in contact at their proximal parts. at the most distal parts, adjacent laterals are not in contact with each other. the outer part of the thallus is composed of the distal ends of individual laterals of alternating arrangement; the inner surface of the thallus is straight. the laterals are slightly inclined to the axis at an angle between 5 to 15º. in tangential sections, the laterals appear as a rounded pore meaning that they are neither longitudinally nor transversally compressed. although cysts have not been observed in our specimens, the swollen laterals suggest a cladosporous type of reproduction. dimensions: see table 2 and fig. 3. remarks: the species in question has repeatedly been confused with macroporella praturloni dragastan (see synonymy). in fact, the laterals with individual calcareous sheets are very similar in tangential sections and also the d/d ratio is the same. m. praturloni, however, is on the whole different from neogyroporella? gawlicki n.sp. by possessing phloiophorous laterals, open at the tips and distinctly inclined to the axis. additionally, m. praturloni is much larger than n.? gawlicki n.sp. with a thallus diameter reaching up to several millimetres (see also bucur, 1985 – table 1). the only species to which neogyroporella? gawlicki n.sp. can be compared to is the type-species n. elegans yabe & toyama. generally, this new species can be regarded as a “mini version” of the latter. n. elegans is distinctly larger than n.? gawlicki n.sp. (see table 3). the d and d values do not show any overlapping areas but are distinctly separated from each other. thus, both species are clearly individual due to their dimensions. in addition, the type-species possess a lower number of laterals (w, see table 3) which more or less thicken at their proximal parts. in addition, a second taxon has been briefly recorded by yabe & toyama (1949) no. d d d/d pmax l h w l 1 0.4 0.1 0.26 2 0.52 0.09 0.28 22 3 0.56 0.18 0.31 4 0.56 0.16 0.28 5 0.59 0.2 0.34 0.09 0.22 24 6 0.62 0.17 0.27 0.055 7 0.64 0.19 0.3 23 8 0.64 0.29 0.185 9 0.67 0.19 0.29 10 0.68 0.2 0.29 21 11 0.68 0.19 0.28 22 12 0.7 0.14 0.2 0.22 13 0.74 0.24 0.32 0.25 14 0.8 0.22 0.28 2.65 15 0.8 0.22 0.28 24 16 0.8 0.2 0.25 24 17 0.8 0.22 0.28 0.08 0.28 0.07–0.08 2.75 18 0.98 0.37 0.38 0.1 0.08–0.09 5.68 19 0.08 20 1.2 0.2 0.17 table 2 the main biometric parameters of neogyroporella? gawlicki n.sp. (in mm). legend: d – outer thallus diameter; d – inner diameter; pmax – maximum diameter of laterals; l – length of laterals; h – distance between whorls; w – number of laterals per whorl; l – maximum observed length. no. 20 – data given by dya (1992). 108 geologia croatica 58/2 as neogyroporella sp. from the same locality as n. elegans. while being distinctly larger than n.? gawlicki n.sp., the number of laterals per whorl (~34) approach the maximum value measured for n.? gawlicki (~26) (see table 3). stratigraphy: based on the aforementioned microfossil assemblages and results of previous and recent investigations, the samples containing neogyroporella? gawlicki n.sp. can be assigned to the late tithonian or early berriasian. the evaluation of the total stratigraphic range, however, cannot be established reliably and surely needs further data. in this connection it should be mentioned that neogyroporella? gawlicki n.sp. has not been detected in the samples of the gerhardstein where the youngest sediments match the kimmeridgian–tithonian boundary or the earliest tithonian. however, the marly limestones containing neogyroporella? gawlicki n.sp. which crop out at the litzelkogel summit represent the final part of the exposed succession. facies and palaeoenvironmental interpretation: the marly limestones that crop out around the summit of the litzelkogel (see fig. 2) follow micrite dominated low energy platform margin deposits that are represented by bacinella–lithocodium bindstones associated with “stromatoporoid” wackestones (genus milleporidium). as no high energy outer central reef deposits characterized by actinostromariids were found, it is assumed that the barrier reef model of turnšek et al. (1981) cannot be applied. it should be noted that the protohalimedacean alga pinnatiporidium frequently associated with neogyroporella? gawlicki n.sp., is according to our own observations, also a typical backreef inhabitant. in a late jurassic–early cretaceous platform model from the east carpathians of romania, dragastan (1999 – fig. 6) also reported on a bindstone facies with lithocodium and pinnatiporidium assigned to a reef-flat facies that passes to a back-reef lagoon facies. therefore, the wackestones, which are partly oncoidal, containing neogyroporella? gawlicki fig. 3 neogyroporella? gawlicki n.sp.: outer diameter of the thallus against the inner diameter of the thallus (d). the parameters d and d are well correlated except the value indicated by dya (1992 – d = 1.2 mm). species neogyroporella elegans neogyroporella sp. neogyroporella? gawlicki n.sp. yabe & toyama yabe & toyama dimensions d 3.5–5.5 3.5 0.4–1.2 d 1.1–1.5 2.1 0.1–0.37 d/d – – 0.185–0.38 p – – 0.055–0.1 l 1.5–2.0 – 0.22–0.28 h – – 0.07–0.09 w about 13 ~34 21–26 l – – 5.68 table 3 dimensions of neogyroporella elegans yabe & toyama, neogyroporella sp. and neogyroporella? gawlicki n.sp. (in mm). 109schlagintweit: neogyroporella? gawlicki n.sp., a new dasycladale... n.sp. may be assigned to a sheltered “back-reef” environment with terrigenous influence (siliciclastic detritus, terrestrial? plant remains). at the dietrichshorn locality, the co-occurrence with zergabriella embergeri (bouroullec & deloffre) may point to freshwater influences (conrad, 1977). indications of a very shallow water setting with signs of subaerial exposure are indicated by components showing circumgranular cracking sensu esteban & klappa (1983). for neogyroporella elegans, yabe & toyama (1949) did not give comments on the facies or associated microflora and microfauna, but the illustrated figurations show a micritic microfacies (wackestones) indicating a quiet water setting. thus, the torinosu formation does not only comprise reefal facies (shiraishi & kano, 2004) but also lagoonal facies, as indicated by the occurrence of wackestones with cladocoropsis mirabilis felix (yabe & toyama, 1927). 4. conclusions neogyroporella? gawlicki n.sp. represents another species of the so-far poorly known genus neogyroporella yabe & toyama. it occurs in marly limestones of the “lärchberg formation” of late tithonian or early berriasian age. this terrigeneously influenced lithofacies, rich in calcareous algae has up to now not been recorded from the alpine plassen formation. thus, many dasycladales that occur together with neogyroporella? gawlicki n.sp., such as zergabriella embergeri (bouroullec & deloffre), deloffrella quercifoliipora granier & michaud or clypeina catinula carozzi, are therefore also missing in the plassen formation. the new species neogyroporella? gawlicki n.sp. furthers the knowledge not only of the poorly known genus neogyroporella yabe & toyama but also of upper jurassic–lower cretaceous dasycladales of the northern calcareous alps. acknowledgements financial support from the austrian science foundation, fwf-project p 16812–b06 is kindly acknowledged. the samples from the dietrichshorn have been provided by r. darga (naturkundemuseum of siegsdorf, bavaria). the material from the litzelkogel has been collected by h.-j. gawlick and s. missoni (university of leoben, austria). both are also thanked for logistic support. the discussion concerning the close affinity of neogyroporella and humiella has been stimulated by m.a. conrad (geneva, switzerland). helpful comments of reviewers m.a. conrad (geneva, switzerland), b. granier (brest) and b. sokač (zagreb) are kindly acknowledged. 5. references barattolo, f. (1991): mesozoic and cenozoic marine benthic calcareous algae.– in: riding, r. (ed.): calcareous algae and stromatolites. springer–verlag, berlin, 504–540. barattolo, f. (1998): dasycladacean green algae and microproblematica of the uppermost cretaceous–paleocene in the karst area (ne italy and slovenia).– dela – opera sazu 4. razr., 34/2, 65–127. barattolo, f. (2002): late cretaceous–paleogene dasycladaleans and the k/t boundary problem. – in: bucur, i.i. & filipescu, s. (eds.): research advances in calcareous algae and microbial carbonates. cluj university press, 17–40. bassoullet, j.-p. (1987): sarfatiella dubari conrad et peybernes 1973: a junior synonym of holosporella siamensis pia 1930.– in: 4th international symposium on fossil algae (cardiff 6-11, july 1987), abstracts, friends of the algae newsletter, 8, 20–21. bassoullet, j.-p., bernier, p., conrad, m.a., deloffre, r. & jaffrezo, m. (1978): les algues dasycladales du jurassique et du crétacé [jurassic and cretaceous dasycladalean algae – in french].– géobios, mém. spéc., 2, 1–330. bucur, i.i. (1985): sur la présence des cysts reproducteurs dans les ramifications de macroporella praturloni et quelques considérations concernant l’évolution de la cladosporie chez les dasycladales fossils [on the occurrence of reproductory cysts within the ramifications of macroporella praturloni and some considerations about the evolution of fossil cladospore dasycladales – in french].– evol. adapt., 2, 101–109. bucur, i.i. (1993): some new or poorly known calcareous algae (dasycladales, gymnocodiacea) in the lower cretaceous deposits from the resita–moldova noua zone (southern carpathians, romania).– rev. esp. de micropal., 25/1, 93–126. conrad, m.a. (1977): the lower cretaceous calcareous algae in the area surrounding geneva (switzerland): biostratigraphy and depositional environments.– in: flügel, e. (ed.): fossil algae. springer-verlag, berlin, heidelberg, new york, 295–300. conrad, m.a. (1982): comments on korkyrella and other new dasycladaceae.– rev. de paléobiol., 1/1, 1–5. darga, r. & schlagintweit, f. (1991): mikrofazies, paläontologie und stratigraphie der lerchkogelkalke (tithon–berrias) des dietrichshorns (salzburger land, nördliche kalkalpen) [microfacies, palaeontology and stratigraphy of the lerchkogel limestone (tithonian– berriasian) of the dietrichshorn – salzburg area, northern calcareous alps – in german].– jahrb. der geol. bundesanst., 134/2, 205–226. de castro, p. (1997): introduzione allo studio in sezione sottile delle dasicladali fossili [introduction to thin-section studies of fossil dasycladales – in italian].– quad. accad. pontaniana, 22, 1-137. deloffre, r. (1988): nouvelle taxonomie des algues dasycladales [new taxonomy of dasycladacean algae – in 110 geologia croatica 58/2 french].– bull. centr. rech. explor.-prod. elf-aquitaine, 12/1, 165–217. dragastan, o. (1999): jurassic–cretaceous calcareous algae of the transylvanides, inner dacides and moesian platform (romania).– rev. espan. de micropal., 31/2, 185–218. dragastan, o., littler, d.s. & littler, m.m. (2002): recent vs. fossil halimeda species of angaur island, palau and adjacent western pacific areas.– acta palaeont. roman., spec. publ., 1, 3–20. dya, m. (1992): mikropaläontologische und fazielle untersuchungen im oberjura zwischen salzburg und lofer [micropalaeontological and facies analysis in the upper jurassic between salzburg and lofer – in german].– unpublished phd thesis, technical university of berlin, 137 p. esteban, m. & klappa, c.f. (1983): subaerial exposure environments.– in: scholle, p.a., bebout, d.g. & moore, c.h. (eds): carbonate depositional environments. am. assoc. petrol. geol. memoir, 33, 1–54. ferneck, f.a. (1962): stratigraphie und fazies im gebiet der mittleren saalach und des reiteralm-gebirges [stratigraphy and facies in the middle part of the saalach area and the reiteralm mountains – in german].– unpubl. phd thesis, technical university of munich, 107 p. frisch, w. & gawlick, h.-j. (2003): the nappe structure of the central northern calcareous alps and its disintegration during miocene tectonic extrusion – a contribution to understanding the orogenic evolution of the eastern alps.– inter. jour. earth sci., 92, 712–727. gawlick, h.-j., frisch, w., vecsei, a., steiger, t. & böhm, f. (1999): the change from rifting to thrusting in the northern calcareous alps as recorded in jurassic sediments.– geol. rundsch., 87, 644–657. gawlick, h.-j. & frisch, w. (2003): the middle to late jurassic carbonate clastic radiolaritic flysch sediments in the northern calcareous alps: sedimentology, basin evolution, and tectonics – an overview.– n. jb. geol. paläont. abh., 230/2–3, 163–213. gawlick, h.-j., schlagintweit, f. & missoni, s. (2005): die barmsteinkalke der typlokalität nordwestlich hallein (hohes tithonium bis tieferes berriasium; salzburger kalkalpen) – sedimentologie, mikrofazies, stratigraphie und mikropaläontologie: neue aspekte zur interpretation der entwicklungsgeschichte der ober-jurakarbonatplattform und der tektonischen interpretation der hallstätter zone von hallein–bad dürrnberg [the barmstein limestones of the type-locality northwest of hallein – late tithonian–early berriasian, salzburg calcareous alps – sedimentology, microfacies, stratigraphy and micropalaeontology – new aspects for the interpretation of the evolution of the hallstatt zone from hallein–bad dürrnberg – in german].– n. jb. geol. paläont. mh.., 236/3, 351–421. granier, b. & deloffre, r. (1993): inventaire critique des algues dasycladales fossils – ii° partie – les algues dasycladales du jurassique et du crétacé [critical inventory of fossil dasycladalean algae – 2nd part – jurassic and cretaceous dasycladalean algae – in french].– rev. de paléobiol., 12/1, 19–65. granier, b., berthou, p.-y. & fourcade, e. (1991): the dasycladalean algae from the cretaceous of the new world.– transactions 2nd geol. conf. geol. soc. trinidad and tobago, port-of-spain (april 3–8, 1990), 178–183. johnson, j.h. (1964): the jurassic algae.– quart. colorado school min., lix/2, 1–129. kügler, u., schlagintweit, f., suzuki, h. & gawlick, h.-j. (2003): stratigraphie und fazies des höheren mittelbis ober-jura im bereich des falkensteinzuges am wolfgangsee, salzkammergut (österreich) mit besonderer berücksichtigung der plassen-formation (kimmeridgium) [stratigraphy and facies of the upper middle to upper jurassic in the falkenstein area at lake st. wolfgang, salzkammergut, austria, with spezial reference of the plassen formation, kimmeridgian – in german].– in: weidinger, j.t., lobitzer, h. & spitzbart, i. (eds.): beiträge zur geologie des salzkammergutes. gmundner geo-studien, 2, 97–106. masse, j.-p., acquaviva, m. & luperto-sinni, e. (1984): humiella catenaeformis (radoičić), nov. comb. (dasycladale) de l’eocrétacé italo-dinarique.revue de micropal., 27/2, 139-143. michaud, f. (1988): neogyroporella? servaisi n.sp., nouvelle dasycladaceae du maastrichtian du chiapas, sud-est du mexique [neogyroporella? servaisi n.sp., a new dasycladale from the maastrichtian of chiapas, se-mexico – in french].– cret. res., 9, 369–378. ohga, h. & iryu, y. (2003): facies analysis of tithonian– berriasian limestone in torinosu area, kochi prefecture, japan.– berichte institut geologie paläontologie karlfranzens-universität graz, 7 (9th int. symp. fossil cnidaria and porifera), 77. ott, e. & flaviani, a. (1983): eine neue kalkalgengattung (lagenoporella, dasycladales) aus dem oberjura von sardinien [a new genus of calcareous algae, lagenoporella, dasycladales, from the upper jurassic of sardinia].– n. jb. geol. paläont. mh., 1983, 3, 16–26. pia, j. (1927): tallophyta.– in: hirmer, m. (ed.): handbuch der paläobotanik. oldenbourg, münchen, 31–136. radoičić, r. (1969): a new lower cretaceous dasycladacea: clypeina pejovici, and note on some clypeina.– geol. romana, 14, 71-84. schlagintweit, f. (1991): neritische oberjuraund unterkreide-kalkgerölle aus den losensteiner schichten (alb–cenomanium) der typlokalität stiedelsbachgraben (oberösterreich; nördliche kalkalpen) [neritic upper jurassic–lower cretaceous carbonate pebbles from the losenstein formation, albian–cenomanian, of the typelocality stiedelsbachgraben, upper austria, northern calcareous alps – in german].– mitteil. ges. geol. bergbaustud. österr., 37, 83–95. schlagintweit, f., gawlick, h.-j. & lein, r. (2003): die plassen-formation der typlokalität (salzkammergut, österreich) – neue daten zur fazies, sedimentologie und stratigraphie [the plassen formation of the type-locality – salzkammergut, austria – new data on facies, sedimentology and stratigraphy – in german].– mitteil. ges. geol. bergbaustud. österr., 46, 1–34. shiraishi, f. & kano, a. (2004): composition and spatial distribution of microencrusters and microbial crusts 111schlagintweit: neogyroporella? gawlicki n.sp., a new dasycladale... in upper jurassic–lowermost cretaceous reef limestone (torinosu limestone, southwest japan).– facies, 50/2, 217–227. sokač, b. (1987): on some controversial dasyclad genera and species and their stratigraphic position in the lower cretaceous deposits of the dinarides.– geol. vjesnik, 40, 9–38. sokač, b. (2001): lower and middle liassic calcareous algae (dasycladales) from mt. velebit (croatia) and mt. trnovski gozd (slovenia) with particular reference to the genus palaeodasycladus (pia, 1920) 1927 and its species.– geol. croat., 54/2, 133–257. sokač, b. & velić, i. (1981): humiella teutae n.sp. (dasycladaceae) from the neocomian of southern herzegovina.– geol. vjesnik, 33, 101–105. tollmann, a. (1976): analyse des klassischen nordalpinen mesozoikums [analysis of the classical north alpine mesozoic – in german].– deuticke, wien, 580 p. turnšek, d., buser, s. & ogorelec, b. (1981): an upper jurassic reef complex from slovenia, yugoslavia.– soc. econ. paleont. mineral., spec. pub., 30, 361–369. yabe, h. & toyama, s. (1927): cladocoropsis mirabilis felix from the torinosu limestone of japan.– japan j. geol. geograph., 5/3, 107–110. yabe, h. & toyama, s. (1949): new dasycladaceae from the jurassic torinosu limestone of the sakawa basin. ii.– proceedings of japan academy, 25/7, 160–164. manuscript received december 06, 2004. revised manuscript accepted november 11, 2005. 112 geologia croatica 58/2 plate i neogyroporella? gawlicki n.sp. from the late tithonian–early berriasian of the northern calcareous alps 1 various oblique sections, dietrichshorn locality. 2 oblique section together with the benthic foraminifera anchispirocyclina lusitanica (egger), dietrichshorn locality. 3 transverse section (left) and various algal fragments, litzelkogel locality, thin-section a–190. 4 oblique section, dietrichshorn locality. 5 oblique–tangential section, holotype, litzelkogel locality, thin-section a–190. 6 detail from fig. 5 showing the close and alternating laterals, litzelkogel locality, thin-section a–190. 7 oblique section, dietrichshorn locality. 8 fragmentary transverse section, dietrichshorn locality. 9 transverse section, dietrichshorn locality. 113schlagintweit plate i 1 2 3 4 6 5 7 8 9 114 geologia croatica 58/2 plate ii neogyroporella? gawlicki n.sp. and other dasycladales from the late tithonian–early berriasian of the northern calcareous alps 1 neogyroporella? gawlicki n.sp., transverse section, dietrichshorn locality. 2 neogyroporella? gawlicki n.sp., tangential section, litzelkogel locality, thin-section a–190. 3 unknown dasycladale with a calcareous envelope consisting of radial-fibrous calcite, dietrichshorn locality. 4 neogyroporella? gawlicki n.sp., detail from pl. i, fig. 8, showing elongated vesiculiferous branch morphology, dietrichshorn locality. 5 branch morphology of gyroporella ampleforata pia (from pia, 1927). 6 clypeina aff. parasolkani farinacci & radoičić, transverse section, dietrichshorn locality. 7 zergabriella embergeri (bouroullec & deloffre), dietrichshorn locality. 8, 10, 12 different sections of deloffrella quercifoliipora granier & michaud, dietrichshorn locality. 9 cylindroporella? sp., dietrichshorn locality. 11 clypeina aff. isabellae masse, bucur & veron, dietrichshorn locality. 13 clypeina catinula carozzi, longitudinal section showing the swelling of the main axis at the vertical plane, dietrichshorn locality. 115schlagintweit plate ii 1 2 3 6 7 4 5 8 9 10 11 12 13 116 geologia croatica 58/2 plate iii neogyroporella? gawlicki n.sp. and other dasycladales and benthic foraminifera from the late tithonian–early berriasian of the northern calcareous alps 1 salpingoporella cf. istriana (gušić), longitudinal section, litzelkogel locality, thin-section ber–17a. 2–5 neogyroporella? gawlicki n.sp. 2–4: oblique sections, thin-sections a–149 and a–182, 5: longitudinal– tangential section, thin-section a–191 (all from litzelkogel locality). 6 montenegrella florifera bernier, litzelkogel locality, thin-section a–189–2. 7 protopeneroplis ultragranulata (gorbatchik), axial section, litzelkogel locality, thin-section ber– 100–2. 8–9 kastamonina abanica sirel, transverse section (8) and subaxial section (9), dietrichshorn locality. 10 chinianella? sp., oblique transverse section, litzelkogel locality, thin-section a–191. 117schlagintweit plate iii 1 2 3 4 5 8 6 7 9 10 118 geologia croatica 58/2 geol. croat. 49/2 247 ·249 zag reb 1996 professional paper critical geological parameters in feasibility studies of exploration projects slobodan kolbah key words: geological parameters, hydrocarbon reservoir, econom ics, exploration. abstract qu.uuitalivc feas ibil ity analysis of exploration projec ts is the basis for r:'iiional exploration and it should be diligently undertaken. the feasibi l i ty stud y should take into accoun t the most cri tical geolog ical parameters which have an impact on the economics o f the ex ploration project. each hydrocarbon accumulat ion has its specific characteristics which arc disclosed in var iolls geologica l data gath. ered during explo rati on work. these data have [0 be in terpreted and sorted olll in a way 10 reflect the most prominent reservo ir charactcr­ isti cs. thc data rep resent the basis for the selection of the most appro­ pri;he deve lopmcnt and production technology . sueh an in teg rat ed and multidisc ip linary approac h is essential for obtaining th e bes t ex ploration resu lt s al the lowcst poss ible cost. 1. introduction feas ibili ty slttciies, with cri tica l regard [or geologi­ cal parameters, have been carried out in ina-naftapl in ex ploration department for several decades . in the late 1960's work started on the sys tematic ga thering and interpretation of geological data and eco­ nomic indi cators. pletikaplc (l984) made a sign ifi ­ can t con tribution with the introduc tion of economic analyscs as an important part of complcx ex plorat ion studi es . in the 1970's f-tajnsek led some explora tio n projec ts as thc hcad o f a team of multidi sc iplinary expert s (hajn sek e t al. . 1978). the present auth or togcther with othcr colleagues, has tri ed to mantain the eoj1linu ily of this work and to develop it further (kol­ ba l-l & ruki\ yini\. 1985). information technology has greatly aided the devel­ opment ancl advancement of preparation of the stud ies. init ially, data processi ng was undertaken us ing main­ fram e comput ers. of course, technology has became more sophisticatcd and naftaplin invested quite a lot in the procure ment of new cquipment and software and trai ning of" it s pe rsonnc l in order to be able to foll ow recen t trends in feas ibility studies. ina in dllstrija nafte d.d. zagreb, naffaplin sektor i. slu zbn islraziv:lilja, subiccva 29, hr-l oooo zagreb, croalia. proceedings kljucne rijeci: geoloski pararn etri , lcziste ug ljikovo­ dika, ekonomika, ist.razivanje, sazetak kvanl ilalivna procje na opravdanosli islrazivackog projek la osno­ va je rac ionainog isl raiivanja, al i i nju je s'lin u nuzno obavljali na mcionalan llilci n. procjeml opravdanosli is traziv ackih projekata treba tl zeli 1i obzi r naj kriticllije geoloske parametre s najvecim uljecajem na ekono­ micnost projekta. svako lezisle ugjji kovodika im" osobite znacaj ke vezane uz raztic ite geoloske paramet rc de finiranc tijekom is tra-liva­ nja. ove podatke treba int crp re tirati i rnzvrslati na nac in koj i ce odrazavati najvaznije z nacajke ldista. kri ticn i panulletr i ujedno prllzaju osnov ll za odabir odgovarajucc tehnolog ije razrade i pro izvodnje. takav illtegrirani i multidi se iplinarni prislup bitan jc za postiz<lllje najboljih istra.zivacki h rez u!t ala li z najni i.e moguce iroskove. t he new organiza tio n of na rt aplin 's ex plora ti o n department , mainl y based o n team wo rk, sh ould cnhance performance resu lts. teams of ex perts incl ud­ ing geophysicis ts, geoche mists, geo logists and econo­ mists work directly on project tasks but indirectly they are also involved in making strategic decis ions. 2. economic analyses economic analyses of ex pl o ration projects arc extremely important. in the oil busincss which involvcs great ri sks (hajnsek et al.. 1978) but a lso g reat potential. it is important to identify and evaluate all the important fac tors which can have an impact on explo­ ration costs (kolbah & ruka ylna. 1985) but also the overall success of an oil project. this is one reason why oil indu stry experts have devi sed a co mpl ex methodology (sego et ai., 1987) for carry ing out slich analys is. this meth odology (mill er, 1987) assumes some typical input data relating to the reservoir charac~ te ristics on one side and economi c parametcrs 0 11 the other, which are then modell ed and interpretcd. the re liability of the input ciata is ex trcmely impor­ tant, e .g. the water depth in off-shore drilling can have a large impact on the economi cs of ex plora tion and pro­ duction , or, changes in taxation policy related to oil pro­ duction can also have positive or negative cffccts on the 24x financial results of a project. for this reason all the data have to be checked and updated. economic appra isa l wil l a lso take into account concession term s, ri sk s preading , politi cal risks and poss ibl e technologica l improve ments. in thc dccision making process the man~ agclllcnt has 10 consider all of the above factors. due to the high degree a/" uncertainty which is inevitably involved in the oil business, some sophisticated meth ~ ods havc becn promoted, like monte carlo simu lati ons and sens itivity ana lyses. an cxploration projec t usually starts with the acc u­ mulation or various reservoir data. gelogical ~geophys i ­ ca l s urveys have to be carried oul. the data are proccssed and inte rp re ted. on the basi s or such data various information can be obtained, including the probability of source and migration , reservo ir rocks, trapping integrity, reservoir thickness, porosity and per~ illcabi lity. 3. importance of critical geological parameters critical geological parameters are derived from th e above surveys. after prospect identification and de fini ­ tion, exploration drilling follows. thi s is the costli est part or exploration. here sav ings are a lready poss iblc if the c ritical geologica l parameters arc bctter defined. arter exploration dril ling is completed, apprai sal of the prospec t will be eas ier as more data are collec ted about the reservoir and the fluid. total reserves can be es timated togethe r wi th recovery potentials. these data a re inc luded in the mode l by wh ich we can dete rmine the 1110s t appropriate technological solutions for devel­ opment wells and fie ld faci lities. however, evcn at this ea rl y s tage by modell ing critical geological parameters and exploratory dri ll ing data we can pred ict the produc­ tion technology and related costs. there a re two differe nt approaches to obtain the required parameters: by gradually defining them ihro~ ugh geo logical properties (from th e cnvironme ntal mode ls to the sand body porosity for exa mpl e), or deducing them in retrospect from the actual production cha rac te ri s tics. however, to some extent it is a lways ex trapolation of data. the best assumptions can be obtained by a combination of both methods. suc h modelling will enable appra isa l ex pe rts to avoid poss ible mistakes and focus on the most c ritica l paramete rs. it will a lso provide information necessary for de finin g " plays", the broadest exp loration unit s wit hin an area. a play is primarily defined by rese r ~ voirs. in the pannonian basin, for example, bas ic plays are in the bascment and pretertiary, o lder te rtiary and lowe r pannonian , upper pannonian , pontian and younger deposits. in the depressions, including mura, drava, sava and s lavonija-s rijem , they are furthermorc distinguished in gcologi<l croatic<i 49(2 the semiregiona l rese rvoi rs w ith comlllon l ilhostrati~ graphi c c harac teristics. it is very impo rt a nt to keep these ident ifica tions in the data base for easier informa­ tion managemcnt as "evide nce of reserves". the re arc o ther imponant da ta related to these reservoirs like strat igraphy, lithology, petrophysica l paramc ters and so on. fluid characteristics can furth e r de fin e "plays" in more details. for example, in the croati an part of the pannonian basin source rocks are dc tcrmincd in the sarmatian and lower pannonian beds. depending 011 the local burial history and other lat c r proccsses we can inte rpret the appearance of oil and gas fields in one area, and gas and gas-condensate fi e ld s in the other. reserves~ in-place depend on reservoirs ancl fluid char­ ac teri stics but , further, they are rela ted to tcc to nic and structural events and pressure/temperature conditions. recovery c ffi ciency is in a g rea t part rela ted to the technical and technologica l approach in produc tion, but it al so de pends on the above mentioned e le mc nt s: petrophys ics of the reservoir , iluid c ha rac te ri s tics and the resulting fluid regime of production. so, critical geological parameters have an impac t on overall upstream activities. economi c analyses are con­ ccntrated on cash now a nd profit definition inc luding parameters such as payout period , rates or re turn and profitabi li ty index uncler certain di sco llnt rates. thcse forccasts are made on the basis of time/cash diagrams. the outputs of such ana lyses enable us to follow and compa rc the viability of the major costs re lated to a project including acqui si tion of land , ex ploration dr ill ing, produc tion s tage including orr~ shore or on~ shore production facilit ies and eq uipmcnt, (ran sporta~ tion sys tem and so on. however, cconomic ana lyses w ill a lso lake into consideration some eleme nts in the downst ream part of the o il bus iness such as marke tin g and di s tribution , rc fining , storage and distribution. or eoursc, at such an early stage of a project these are only hi gh level analy~ scs and forecasts. yet, they are important bccause early information can help us to avoid ri sks and losses. for exa mple, in the case or a gas prospec t in the kanay is concession in egypt , a cha nge in the price of the product of i s/mcf res ulted in break ing through the economical threshold , to ge tting nearl y 15 $mm after tax cash flow discounted at a rat e o r 15%. 1n ano the r example in libya, the economi cs of the reser~ voir c hanged dramat icall y depe ndi ng on the th ickness of the pay zonc. a change of several metres a ffectcclthe brcak-even threshold va lue by approximate ly 100 $mm of after tax cash now d iscou nted at 15% ra te. in an off-shore project s imilar analys is showed that the critical parameter was well productivity. in calc ula­ tions taking into account bc fore tax valucs the threshold was at about 2 mbbl/day. by increasing welj ~productiv­ it y th e other va lu es werc al so inc reased. however, kolbah: crili!.:al gcologic;l l par.mlelers in f'easibility studies of exploration projects 249 when we took into account production sharing te rms, 5. refe rences the economics of the project proved 10 be less att ractive even at high productivity values. hajnsek, b. , kolb a f-i , s . & rukavi na, b. 4. conclusion thi s papcr was prepared for the first int erna tional symposium of petroleum geology economic aspects o r petro iclim exploration an approach to rat ional exploration which was held in zagreb in april 1996. it reveals part of the effo rts of in a naftaplin exploration department to promote econom ic analyscs in explo­ ration survcys . the economic aspect of exploration work has not always been properly valued. the present aut hor has tried to emphasise the potentia ls of econom­ ic anal yses and how they can predic t the success of a pctroleum project and make it more rational. ( 1978) : probability of hydrocarbon di sco ve ry in some areas of the adriati c.xxv i congress and plenar assembly i.c.s.e.m. , proceedings, 135137, antalya. kolbah, s. & rukavi na , b. ( 1985): analysis of drilling depths, time and costs in pannonian basin and adria tic subsea area at thc bcgin nin g o r the e igh li es.fourth adriati c symposium or oil tech­ nology, proceedings, 10, 518, cavtat. miller , n. (1987): explorat ion cconornics.interna­ tional i-iuman resources devclopmcnt corporation, boston, 82p. pletikaple , z. ( 1984): modifica tion or the newen­ dorp 's monte carlo simulation procedure of the ne t­ present values of petro leum and gas reservcs.na f"­ ta , 35/1 2, 617-627 , zagreb. sego, b., kolb ah, s. , r ukavi na, b. & skelln, k. ( 1987): data base for the appraisal of hydrocar­ bo n rescrves. 9th intern ational syrnpo~ium com­ puters at university, proceedings, 346-35 1, cavtat. 250 geologia croalic:l 49(2 geol. croa t. 50/2 261 268 3 figs. zagreb 1997 stratigraphy and tectonic relationships along the senj -ogulin profile (velika kapela mt., croatia) dubravko ma ticec, igor vlahovic , ladis lav fucek, nenad ostric and ivo velic key words: shallow-water carbonates, compressive tert iary tectonics, transpressive neotectonics, stru­ ctures, jurassic, lower cretaceous, dinaridcs, veli­ ka kapela mi. , croatia. abstract t welve lilhostratigr<lphic units, representing a 5 km thick succes­ sion, have been determined from the scnj -ogulin profile through the velika kapcla me thi s 45 km long sequence lies approximately nor­ mal lo the dinaric strike. carbonate deposits ranging from the middl e liassic 10 the albian incl ude laterall y variabl e environments during the k immeridgian and lower t ithonian. the deposits were defonncd by compressive tectonics duri ng the tertiary tectonic cycle, and wc re consequen tl y rcshaped by weaker neotectonic transpression. there­ fore structures with the n-s strike, wh ich are different to the common dinaric strike (nw-se) , arc interpretcd as a consequence of synge­ net ic l>cnding during the tertiary cycle, rather than rotation during the ncoiectonic cycle. 1. introduction geological in ves tigati ons of the senj -ogulin profile th rough the velika kapela mt. , were part of the project ent itled «geological analysis of part of the primorje and gorski kotar", perrormed by the tnstitute of geology, zagreb, for the ina-naflaplin company. therefore, we are gratefu l to ina-naftapjin for permission to publi sh some or the results. the ill ost important contributions to the geological know ledge of study area were obtai ned by systematic geological investigations performed during work on the basi c geological map i: 100,000 of the ogu lin sheet (veli c & sokac, 198 1; velic et ai., 1982) and parts or the crikveni ea (susnjar et ai. , 1970; grt­ man i et al.. 1973) and rab sheets (mamuzic et a \. , 1969; mamuztc & milan, 1973 ). in these works mesozoic deposits were accurately subdivided, and the basic geological relationships in th is part of the dinar­ ides were presented. institute of gcology, $achsova 2, p.o. box 268, hr1oooo zagreb, croatia. 2. stratigraphic review the investigated area is composed of shallow-water platform carbonates of jurassic anci lower cretaceous age (fi g. i). twelve lithostrat igrap hic units with an approximate total thickness of 5,000 m were es tabl ished (fig. 2). si nce the study area has a very compl ex geo­ logical composition, especially due to the intense post­ depositional tectonics, it was not possible to form al ise the unit s; therefore, the units descri bed in thi s paper represent informal lith ostratigraph ic units. all hou gh determined fossil assemblages were very rich , onl y the most im po rtant index fossils are mentioned in thi s revicw. data on the thickness of the stratigraphic unit s are based upon our investigation, as well as on compar­ isons with the results presented in the aforemen ti oned sheets of the basic geological map i: 100,000. 2. 1. lithostratigraphi c unit a deposits of lithostratigraphic uni t a are represent­ ed by mostly is-50 em thi ck well-bedded dark gray to black mudstones with variable proport ions of peloids and bioelasts. beds containing li ght-coloured gas­ tropods, onco id s, benthic foram inife ra, echinoderms and ostracods are infrequent. in the uppermost part therc are gra instoncs, scarce marly beds and beds con­ taining molluscs of the genus lithio/is. the thickness of unit a is approximately 400 m. on the bas is of the foss il assemblage (orbilopsella praecursor and lirilio/is prohlemalica) it has been dete­ rmined that depos its o f uni t a are or middle liassic age. they were deposited mostly in the low-energy sub­ tidal environments with sporadic shallowing. 2.2. lithostratigraphi c un it b intense bioturbation, resulting in a mott led appear­ ance of the rocks (their common name is "spotty li me­ stones", or ':fleckenkalk" in german) is the main charac­ terist ic of the unit b. deposits are represented by alter­ nating 30-70 em thick beds of gray to almost black this paper was presented at the scientific meeting dedicated to the 80th anniversary of the life of professor milan herak, held on march 5th, 1997 in zagreb 162 iii ;·hreljin ogutinski ,~ ..(' vi ;, 16 • ....... , .....: · ogulin '\:.:\. ...... v . ~ : '+/ iv-8 geologia cro:liica son structural units: i krivi put ii pepelarnica iii tomich •••• ; krivi put iv dreinica "j..... 1-8 v klek ... vi hreljin ogulinski enj i-a skm d lower cretaceous d maim adriatic sea d dogger fig. 1 loca tion map with simplificd geological map and structural unit s described in the text. profile line lias mudstones and nodul ar peloidal packstones . skcletal ­ peloidal grainstone beds with swaley cross-stratification sporadically occu r, as well as ooid-oncoid-favreina packstones. at the top or the un it, an approximately 15 m thick package of late-diagenetic dolomites occurs, which is a common characteristic of the uppermost part of contemporaneous deposits throughout the dinarides. the complete thickness of lithostratigraphic unit b is approximately 130 m. deposits of th is unit are of upper liassic age, and were deposited in somewhat deeper, lagoonal environ ­ ments, near to or just beneath fair-weather wave base. 2.3. lithostratigraphic unit c in the lowermost part of these deposits alternations of mudstones and hummocky cross-s trat ified peloid packstones predominates, while in the rest of the unit , only scarce mass ive beds of ooid-peloid packstones occur within the prevailing mudstones. original grain­ stones are sporadicall y completely late-diagenetically do lom itized . the complete thickness of the unit is approximately 400 m. based on the microfossil assemblage (a1esoell­ dolliyra crogrica and selliporella dollzellii ) a lowe r dogge r age has been determined fo r this unit. the depositional environment was a low-energy subtida l lagoon wit h sporadic progradation of shall ow-wate r sand bars. 2.4. lithostratigraphic unit d in the lower 100 m of unit d there are numerolis beds of skeletal-oncoid-peloidal wackeslones, intraclas­ tic-oncoid-gastropod fioalslones and ooid packstonc/ g rai nstones wit hin the prevailing thick-bedded mud ­ stones, as well as scarce beds indicating emers ions. in the upper part 1-2 m th ick beds of brown to gray-brown mudstones with interbeds of light-coloured int raclasts, oncoids and ostracods predomi nate. lithostrat igraphic unit d is approximately 400 m thick. according to the microfossil content (pa/eop/ellde­ rina sa/erniwna and salorino apuliensis) this un it is of upper dogger age (bathonian callovian). the deposi­ tional environment was a low-energy subt idal lagoon with infrequent shallowing. ." ~. ,0 <n r. if ~ o· g '5 " [ 2o ~ ~. ~ ~ o 0§. & ~ ~ ciq. ~ g o· ~. ~ ~ 9. 8: " ~ g o o o o o o " o o o tithonian 1500 m o clypeina jurassica campbel/iella striata middle liassic orbitopsella praecursor lithiotis problematiea o " early dogger o o o o o o o o 400 m (") mesoendothyra eroatica selliporejla donzellii neocomian barremian aplian al bian 400 m 250 m 150-250 m 400 m o b rn w o 0 1 oq !d c:j i !l jl v · . ~h:l <& o ip '0 'i? 1) 0) ii ~ q) o . o ~ o i!i ijj 1 ~ !l ~ !, 1 0 1 . p 01 ijj ·0 iij epimastopora cekici clypeina solkani favreina dinarica f. njegosensis ~i . ii r salpingoporella dina~ica orbitolina (m.) texana a p~gopor:lba m~ itae palorbitolina lenticularis valdanehella dercour1i . mue ergn orbitolina (m.) parva salpingoporella turgida late dogger 400 m 0 0 o ~i 0 0 0 0 0 0 • 0 o iii 0 0 0 0 0 paleopfenderina salemi/ana satorina apuliensis oxfordian il ) salpingoporella sellii i kumubia palastiniensis [ nautiloculina oolithica trocholina gr. alpina­ elongata tithonian 400 m ellipsactinia ellipsoidea \ sphaeractinia diehotoma \ nerinea defrancei pseudoclypeina cirici i pfygmatis bruntrutana conieokurnubia orbitoliniformis .. o o 0 1 0 o o o o age thickness llthostr. units r ~ o r o gl -< fossils " (';< o o " ~ ~ rr.:. ~ -< " ~ ii' 3 o o ~ , -g > 0'" ;; ~ ~. ~ o ~ ~ " n 2; 2.5. lithostratigraphic unit e depos ils o r lhis unil are represenled by lhiek-bed­ ded (0.51 m), slylol ilized dark-gray mudslones and oncoid-foraminiferal wackestones with abundant aeoli· saccus sections and oncoids. a large part of these depo­ si ls is eomplele ly lale-diagenelieally dolomilized , rep­ resenting coarse-crystalline dark gray to almost black dolomites of mass ive structure. the complete thickness of lithostratigraphic unit e is approximately 400 iti. the oxfordian age of this unit has been determined on the basis of a benthic foraminiferal assemblage (ku ­ mlfbia pa/oslilliellsis, nallli/oculing doli/hiea, trocllo­ ling gr. a/pino-e/on gara) and green algae (sa/pillgopo­ rella sellii). the depositional environment was subtidal of predominantly low energy level. 2.6. lithostratigraphic unit f in the centra l area of the velika kapc la mt. , as observed in the senj-ogulin profi le, de pos its o f the middle and uppe r maim show important fac ies vari­ ability , as a consequence of the palaeogeographical dif­ fe rentiation caused by synsedimentary tectonics (vel­ ie el ai., 1994). consequenlly, in the midd le maim lwo diffe re nt lateral developments have becn determined: the profi le mostly comprises typica l shallow-wa ter depos ils (f,) wel l-bedded gray lo dark gray mudslones with oncoi cl s, intracl as ts and frequent benthic forami ­ nifera, wh ile in the area of dreznica very restri cted out­ crops of limes tones with chert (f2) occur, representing a somewhat deeper, lagoonal equivalent of the contempo­ raneous fl de posits. on the basis of the available data , the thickness o f lithostratigraph ic unit f is estimated as 150 ill. the micro foss il assemblage (psel/doclypeifia cirici and cojlicokurllubia orbitolilllformis) and s tratigraphic re lat ions over a wider area indicate a kimmeridgian age for these deposits. 2.7. lithostratigraphic unit g the lowermost part of the tithonian in the kriv i put senj a rea is re presented by rarely preserved hydro­ zoan-coral-bryozoan-gastropod reefs, and large amo­ unts o f pe ri -ree fal mate rial produced by their dis inte ­ grat ion. the reefs were form ed in the marginal areas of a lagoon, while in the deeper parts limestones with che­ rts were contemporaneous ly deposi ted. the re fore, in the progradationa l succession, peri-reefal reefal depo­ s it s are always fou nd overlying the limestones wi th c he ri (lith ostrati graphic unit f2), while this uni t is complete ly missing in areas where shallow-wate r depo­ sition during the kimmeridgian, (as represented by unit f 1) , continued into shallow-water tithonian sedimenta­ tion. bioc lasti c material is mixed with ooids formed in shallows with agitated water in back-reef areas , with a prog ress ively hi gher proport ion of ooids towards the uppe r pari of the unit. the complele lhiekness of unil g de pos il s is eslimaled al 400 m. on the basis of biostratigraphic data , (mostly m ac­ rofauna including ellipsaclinia ellipsoidea, sphaerac­ linia dicholoma, nerinea (/e/rancei, ptygmatis brllnlru­ tana), as well as regional geological re la tionships, this uni t is de temlined as being lower tithonian in age . 2.8. lithostratigraphi c unit h in the southern part of the study area, be tween krivi put and senj, tithonian peritidal deposit s concordantly overlie peri-reefal reefal deposi ts of the lowe r titho­ nian (lithostratigraphi c unit g), while in the northern area be tween dreznicko polje and ogulin they direc tly overlie kimmeridgian shallow-water deposits. in the kr ivi pu t senj area the transition from the underlying deposi ls is gradual. in the 10wellllosl 280 m well bedded lig ht gray mudstones and fe nes tra l mud­ stones with beds of peloida l-algal wackcstones (com­ pris ing clypeina and sa/pingoporella ) predominate, although infrequent in te rbed s containing hyd rozoan, and scarcer coral , gas tropod and bryozoan b ioclasts a lso occur. the proportion of ooids is highest in the lowe r pan, and gradually, although somewhat irregular­ ly , decreases lowards the uppe r parl of the unit. the remainder of the unit, (approximate ly 1,200 m ), is characte rised by mudstones with variable proportions of 0.5 1 m thick laminites of differen t origin s : some lami nation is caused by se lec ti ve dolomitization and dedo lomi ti zation, some by fe nestral fabric , and others by the alte rnation of mudstones and gra instones . the amount s of clypeina bioclasts is ve ry variable, and fro m the middle part towards the top of the uni t camp­ bel/iella striata and favreina pe lle ts are freq ue nt in som e layers. in the uppermost part depos it s are ih in­ bedded , and some beds with os treid bioc las ts were observed. the peritidal success ion in the northe rn area is generally similar, but is characterised by lesser amounts of ooids, and very infrequent bi oclas ts (as a con se­ quence of the distance from the reefs). deposits of lithostratigraph ic unit i-i are of tithon­ ian age. it is clear that depos ition of the uni t in the northern part of the s tudy area commenced during the earlies t tithonian, while in the southe rn area peritidal deposition was established somewhat late r. the refore, the th ickness of the unit is variable, but can be es tima­ led al 1,500 m. 2.9. lithostratigraphic unit i li thostratigraphic unit i is characteri sed by thick­ bedded (>0.5 m), almosl eomplele ly unross ilire rous brown mudstones w ith very rare bed s of fav reina wackestone-packstone, and , in the upper part , late-dia­ genetica lly dolomitized lam inites. tn the senj area mud­ stones comprise variable portions of small voids formed by solution of the unstable mineral compon e nts. the complete thickness of this unit is approximately 400 m. it has been detennined that the lower 200 m of this unit contains a fossil assemblage characteris tic for the m;lliccc ct ;11.: stratigraphy and tt."ctonic relationships along the scnj-ogu lin profile ... 265 uppermost tithonian to neocomian, while its upper part is definit ely of neocomian age (acco rdin g to the assemblage charac teri sed by epil1lasropora cekici, cly­ pc ina so/kalli, favreina dinarica and f. njegosclisis). depositional environments were mostly characteristic of lagoonal conditions with infrequent shallowing to the upper subtidal/intert idal , cspecially in the upper part. 2. 10. lithostratigraphic unit j deposits or lithostratigraphic unit j arc very infre­ quent in the study area, and arc represented by alternati­ on of wel l·bedded (30·50 em) gray· brown peloid-skele­ tal wackes tone-packstones with rare rnudslone laminae. the thi ckness of the un it is approximately 250 m. common green algae (sn/pingoporel/g melilgc and s. 17ll1chlhergii) indicate a barremian age for these shal­ low-water deposits. 2.1 i. lithostratigraph ic unit k lithost rati graphic unit k is represented by thick­ bedded light-brown to brown-gray mudstones with a relat ively ri ch fossil assem bl age, dominated by palor­ bi t olin ids. therefore, thi s unit corresponds to the depo­ s its which arc in the dinarides known as "the lower orbitolina limestones". the upper 100 m of the unit is thi n-bedded, charac te rised by predominating pel oid­ int raclast-ske letal wackestones and packstones. the ihickness of ihe unil is approximalely 150-250 m. the microfoss il assemblage (sa/pingoporel/a dinar­ ica, pa/orbitolina lemicillaris and orbitolillg (m.) par­ va) indicates an aptian agc. deposits of thi s unit arc characteristic of deeper lagoonal conditi ons wi th grad­ ual shallowing, ending with the regionally known apt­ ian emersion in the upper part of the unit. 2. 12. lithostratigraphic unit l depos its of lithostratigraphi c un it l are charac­ lerised by ihe allernalion of well -bedded (30 em) mud­ stones and pe lo id-intraclast-skeletal packstone/grain­ stoncs containing oncoids. laminati on was sporadically observed, characte rised by the alternat ion of mudstone and packstone laminae. the most important fossils are mcsorbitolinids, and the unit corresponds to the level of '"the uppcr o rbitolina limestones" in the dinarides. the thickness of the unit is approximately 400 m. on the basis o r the dete rm ined foss il assemblage (orbiroli lla (m.) texgiig, va/danchella dercourti, salp ­ iflgoporel/a turgida) this unit is of albian age. deposi­ tiona l envi ronments arc mostly charac teri stic of shal ­ low-subtidal cond itions. 3. structural relations tracing of the determined lithostrat igraphic succes­ sion along the profile resulted in the geologi ca l map (s implified in fig. i). from previous knowledge it was already possible to assume that the geological structure of this pan of the dinarides represents the consequence of two periods of tectonic activity, characterised by different orientations of the reg ional stress . during the tertiary tectonic cycle, which lasted from the eoccne to the end of the mi ocene, compressive movements orien ted ne-s w reached their cumulati ve maxi mum with o rogenesis of (he dinarides. during the later, neotectonic period, the main stress changed to n-s, resulting in furth er uplirt and transpress ive de formation of the older structures . namely, faulls of ihe dinaric slrike (nw-se) , whieh were favourably oriented structures towards th e new stress regime (approximately under the angle of 45°), were reactivated int o faults with dex tral strike-s lip movement. therefore, during the in ves ti gation of the senj -ogulin profile special a ttenti on was pa id to the contacts of the established structural units, in orde r to defi ne their mutual relations. inves tigation of the field relationships of the di iter­ ent lithostratigraphic unit s, and structural analys is of the tectonic fabri cs, has resulted in determinati on o r six different structural unit s, di vided by significant fa ult s with a relat ively high component of vertical movement (in some cases more ihan 1,000 m). 3.1. ti-ie krivi put structural unit the krivi put structural unit encompasses the southwestern most part of the study area (figs. i & 3, i). it represents a large anti clina l structure composed of ti thon ian carbonates (lithostratigraphic uni ts g & i-t), with a b-axis orientation (n-s) very differen t from the dinaric strike. the almost undisturbed wes tern limb of the structure, (fig. 1 & 3, i-a), including the conti nu ­ ous transition into (he lower cretaceou s deposits (lithostrati graphic unit i), shows no signs of rotation. furthermore, comm on traces of reverse int erl ayer movements indicate exclusively compression normal to the structure. cons idering the intensity of the de forma­ tion during the tertiary tectonic cycle, when elements of the older tectonics were more or less des troyed, it is not probable that this structure is inherited from the old­ er, cretaceous tectonic cycle. thi s structure probably result ed from deviated loca l stress during the tertiary tecton ic cycle. the apical parts of the struc ture, as well as ils easlern limb (figs. i & 3, i-b) were desiroyed by faults o f dinaric stri ke wi th traces of dextral movement. these faults represent the structures which are inherited from the tertiary cyc le, and were subsequently react i­ vated by the neotectonic activity. geologia croaljca :juri. ~ hreljin _ v ~gulinski .0 0 i-a i-b ii iii i iv-a iv-b v vi ·1000 -, , i vi structural units ~i~~~~t~!~igr~~~ii~~~fitd~posits of (upper liassic) fig. 3 schematic geological cross-section representing structural units and diagrams of bedding traces. 3.2 . the pepelarnica structural unit the pepelarnica structural unit (figs. i & 3, ii) is separated from the krivi put unit by a wide crushed and doiomitised zone. such a wide zone probably resulted from neotectonic reactivation of the inherited reverse fault of dinaric strike into the dextral strike-slip fault. this structure is only peripherally encompassed by the profile, in the part where it appears as a gentle syncline. however, northwestward it outcrops as a dis­ tinct structure. in its central part it is composed of the dogger deposits, i.e. lithostratigraphic units c & d, while in the marginal parts upper liassic carbonates (lithostratigraphic unit b) outcrop. it is probable that the krivi put and pepelarnica units originally repre­ sented a single anticline-synclinc structure, which was subsequently destroyed by the reverse movement along the listric fault of sw vergence, with the vertical com­ ponent exceeding 1,000 iii (ti thonian and upper lias­ sic deposits are in contact). 3.3. the tomici structural unit the tomici structural unit (figs. 1 & 3, iii) is also in rcverse relation to the pepelarnica unit, but with the opposite vergence. along this backthrust, the vertical component of movement also exceeds 1,000 m (nw of the tomici village a contact between tithonian and upper liassic deposits also occurs). deposits of this unit, comprising maim carbonates (lithostratigraphic units e, f & h) uniformly inclined towards the ne, are, in the area of the lug polje, in a similar situation to the dreznicko poljc arca in the neighbouring dreznica unit as they are compressed between a reverse listric fault with a large vertical movement from ne and a strong backthrust from sw. both poljcs arc chara­ cterised by numerous large-scale sinkholes, which res­ ulted from neotectonic reactivation of inherited ter­ tiary faults. this reactivation, in the form of transpres­ sion, formed the new faults, the orientation of which (e-w strike) corresponds to the p ruptures in the newly established ellipsoid of deformation. dcxtral moveme­ nts along their fault planes caused opening of deeply pcnctrative axial plane cleavage of the inherited dinaric structures. 3.4. the dreznica structural unit the dreinica structural unit (figs. 1 & 3, iv) could be divided into two parts. the southwestern part (figs. i & 3, iv-a) is strongly tectonically disturbed, since the oxfordian deposits (lithostratigraphic unit e) in its frontal part are uplifted in the form of an imbrica­ ted listric fan towards the west for approximate i y 650 iii (the oxfordian and tithonian deposits are in contact). the backthrust along the southwestern margin of the dreznicko polje has a vert ical componcnt of movement of approximately 700 m (uppermost tithonian deposits of lithostratigraphic unit h are uplifted to the level of aptian sedimentary rocks in the footwall). the polje represents a deformed syncline composed of lower aptian and albian deposits (lithostratigraphic units k & l), pushed from the northeast along the fault with approximately 700 m of vertical movement (lowermost neocomian and albian are ill the contact). this fault forms a boundary with the northeastern part of the l"laticcc ct a l.: sir.liigraphy :mll t(.'c lon ic relationships along lhe scnj · ogulin profile... 267 drezn ica st ru ctural uni t (figs. i & 3, iv -b), which the basic characteri st ics of 12 info rmallithost rati represents a gcntl e, spaci ous antic line-syncline com­ posed mostly 01" tithonian deposits (lithostratigraphic unit h), disturbed by a fault of uncertain characteris­ tics. northeastward of thi s fault , the uppermost kim ­ meridgian outcrops (lithostratig raphic unit f ,), but approximation of the amount of vertical movcment is very difficult. namely, the major problem in the esti ­ mation of the vertica l component of movement in the northeastern part of the profile lies in the fac t that the tithonian deposits, which were observed in the contacts along all fau lts, are very thick and lithologically homo­ ge neous. there fore, it is very difficult to de termine which part of the tithonian succession is ex posed along thc rclat ively narrow area investigated by geological mapping along the profile line. 3.5. the klek structural un it along the profil e the klek structural unit (figs. & 3, v) begin s with a strongly tec tonically di sturbed zone. ncotecton ic ac ti vity caused reacti va tion of the o lder rcvcrse fault s of dinaric strike into the dextral strike-slip fau lts, which resulted in obscureness of the primary tectonic contac ts. however, from the sporadi­ cally visible rela tionships between the tectonic bound­ ary and the morphology it is clear that thi s is the inher­ ited reverse fault of ne vcrgence. the area near the fault is charac terised by strong crumbling of the foot ­ wa ll and a wide zone of tectonic brecc ia. with the exception of a narrow zone of neocomian deposits (lithostratigraphic unit i) out cropping in the men­ ti oned tectonic zone, thi s uni t is composed of the almo­ st com plete ly dol omi ti zed tithonian deposits (lithos­ tratig raphi c unit i-i). beds in the kick structural unit are uniforml y incl ined towards the southwest. 3.6. the hr eljin ogulinski structural unit the boundary between the i-lreljin ogulinski struc­ tural unit (figs. i & 3, vi) and the kiek structu ral unit is characterised by a reverse fault caused by movement of the kick uni t towa rds the northeast. howcve r, because of the aforemen tioned problem with the esti­ mation of the thickness of the tithoni an deposits, it is not possible 10 determine precisely the amount of verti­ ca l movemen t along the fau lt. however, the vertical com ponent of ill ovement is important , since the cieposits of the footwall are of the uppermost tithonian age (as ind icated in the vicinity by outcropping of the lower crctaceous in thc continuous succession). 4. review of the res ults some results of the present stu dy contribute to a bette r knowledge and undcrstand ing of the geo logical relat ionships in th is part of the dinarides: graphic units, ranging in age from the middle liassic to the albian have been determined, including their fo ssil assemblages, lithology and depositional environments. the ex istence of laterall y different environments during the kimmeridgian and lowcr tithonian is proven, as a consequence of palaeogeograph ic differ­ ences probably caused by synsedime ntary tectonic activity. the tectogenesis of the dinarides is the culllul ati ve effect of two teclonically act ive periods terti ary and neotectonic. during the tertiary tectonic cycle struc­ tures were formed by the ne-sw orientated compres­ sional tectonics (structures of the dinaric strike). sub­ sequentl y these structures were reshaped by the trans­ press ional neotectonic activity, when the older faults were reactivated into the dextral strike-slip fault s by the change of regional stress direction to the n-s. however, in the study area traces of the neotectonic activity are very common , and arc mainly represented by gent le striae, but the inherited tertiary structures are still well preserved. therefore, it may be concluded that the influence of the neotectonic ac tivi ty in the area of the inves tigated profile should not be overstated. the structures of the n-s strikc (i.e. the krivi put structural unit) , whi ch are different from the dinaric strike, show no signs of subsequent rotation. this fac t, together with other indicators of ncotectonic acti vi ty, indicate that thesc st ructu res are the result of the syn­ genetic bending along the strike, probably ca used by the local deviation of stress during the tert iary tectonic cycle. sincc the presented result s were obtained on a sin­ gle profile through the dinar ides (although invest igated in deta il , and alm ost 4s km long) they do no t allow comprehensive concl usions to be drawn about the rela­ tionships of a regional area. however, they complement additional data, including seismi c in ves tigati on and study of other profiles, and certainly represent a contri ­ bution to a more complete knowledgc of the structure of the dinarides. 5. refer ences grimani, i. , susnjar, m. , bukovac, j., mi­ lan , a., nikler , l., crnolatac, i. , s ikic, d. & blaskovic, i. ( 1973): osnovna geo loska kana sfrj 1:100.000. tumac za li s t crikvenica l33102 (geology of the crikvenica shect).insl. geo l. istrai. zagreb ( 1963), say. geo l. zavod, beograd, 47 p. mamuzic, p. & milan, a. ( 1973): osnovna geo­ loska karta sfrj i: 100.000. tumac za list rab l3311 4 (geo logy of the rab sheet).institut za geoloska istrazivanja zagreb (i966), savezni gco­ loski zavod bcograd, 39 p. 26s mamuzic, p. , milan , a. , korolija , b., boro­ vic, i. & majcen, z. ( 1969): osnovna geoloska karta sfrj i : 100.000. li st rab l33-1i4.institut za gcoloska islrai ivanja zagreb ( 1959-1965), savczni geo!oski zavad beograd. susnja r, m., bukovac, j. , nikler, l., crno­ latac, i. , milan, a., sikic, d. , grim ani, i. , vullc, z. & blaskovic, l. (1970): osnovna geo loska karta sfrj 1: 100.000. li st crikveni ca l33102.insl. geol. istraz., zagreb ( 1961 1969), say. geo!. zavod, beograd. vellc, i. & so kac, b. (1981 ): osnovna geoloska karta sfrj i :100.000. list ogulin l33-103.geol. geologia croaticil 5012 zavod oour za geol. paleonl. , zag reb (19711986), sav. geol. zavod, beograd. velic, i. , sokac, b. & sca vnica r, b. ( 1982): osnovna geoloska kart a sfrj i: 100.000. tumac za list ogulin l33-103 (geology of the ogulin sheet).­ geol. zavod oour za gco l. palconl. , zagreb (1980), say. geol. zavod, beograd, 46 p. vellc, 1. , vlahovic, i. & tisliar, j. (1994): late jurass ic lateral and vertical facies distribution: from peritidal and inner carbonate ramps to pc ri recfai ancl peritidal deposits in se gorski kotar (c roat ia). ­ geologie mediterraneennc, xxl/3-4, 177180. manuscri pt received apri l 14, 1997. revised manuscript accepted november 10, 1997. i geol. croat. 49/1 117 127 8 figs. zagreb 1996 i eocene limestones overlying lower cretaceous deposits of western lstria (croatia): did some parts of present lstria form land during the cretaceous? dubravko ma ticec' . igor vlahovic ', ivo velic' and josip tisljar' key words: cretaceous tec toni c cyc le, cretaceous land, western istrian anticl ine st ructure, transgres­ sive eocene limestones, adriatic carbonate plat­ form, tstria, croat ia. abstract in the region of (he western islrian anticline, eros ional remains of lhe transgressive eocene foraminiferal limestones overly shall ow­ water deposits of early cretaceous age (valanginian, hauterivian and barremian). this evidence, together with the ocurrencc of baux ite deposits and palaeogene beds overlying albian, cenomanian and senonian limestones indicate the very high relief of the land trans­ gressed by the palaeogene sea. contrary to the traditional connection belweellthe formation of the western istrian anticline and the larami­ an tectonic phase at the end of the cretaceous (maastri chtian), new investigations suggest sporadic tectonic movements (w ith conslall! tectonic coordinate orientation) from the hauterivian to the end of the cretaceous. with these movements, formation of the anticline struc­ ture began in the early cretaceolls, with the emerged apical paris rep­ resenting land areas throughou t most of the cretaceous. i. introduction recent systematic geological investigations in west­ ern istria (fig. 1), espec ially during research for the 1:50,000 scale geological map of the republic of croalia indicate a need for a new interpretation of the geological evolution of the istrian peninsula during the cretaceous and older tertiary. previous interpretations were based on the results of investigations for the basic geological map (polsak & sikic. 1969), as repre­ sented in the explanatory notes of thc rovinj sheet (pols ak & sik ic, 1973) . the authors of subsequent papers 011 the geology of central and western 1st ria accepted the tectonic scheme from this work, where the dominant st ruc ture, the nne-ssw oriented western istrian anticline, is interi tnstitlltc of geology, sachsova 2, hr-l 0000 zagreb, croat ia. 2 faculty of mining, geology and petrolcum engineering, university of zagreb, pierottijeva 6. hri 0000 zagreb, croatia. kljucne rijeci: kredni tektonski ciklus, kredno kopno, zapadnoi starska antiklinalna struklura, transgresivni eocenski vapnenci, j adranska karbonatna platforma, istra, hrvatska. sazetak u podrucju zapadnoistarske alltikjillale utvrdene su pojave erozi ­ jskih ostataka transgresivnih eocenskih foraminiferskih vapnenaca na pl itkovodnim nas lagama donje krede (valendis u, otrivu i baremu). ti nalazi zajedno s pojavama boksita i paleogenskih naslaga na albskim, eenomanskim i senonskim vapnencima, ukazuju na izrazit reljef ko­ pna na kojc jc transgrediralo paleogensko mo re. nasuprol dosada­ snjern vezivanju nastanka zapad noistarske antiklinale za laramijsk u lektonsku fazu krajem krede (u mastrihtu), rezu ltati novijih istraziva­ nja ukazuju da su povremeni tektonski pokreti djelovali od otriva do kraja hede s istom orijentacijom tektonskih koordinata. tim je pokretima vce u starijoj kredi zapocc1o fonniranjc antiklinalnc s tru­ klure, cij i je emergirani sred isnji dio predstavljao kopno tijekom gotovo cijek krede. dakjc, podrucje zapadnoistarske antiklinale jc u mlademu dije lu starije krede i mladoj hedi bilo kopno! preted as being fo rm ed by the end of the late creta­ ceous during the laramian tec tonic phase. as the influ­ ence of the laramian tectonic phase declined by the end of the cretaceous and beginning of the pa laeogene, the new, pyrrenean tectonic phase began. this was charac­ terised by a change in the orientation of the compres ­ sion of the carbonate platform, i.e. the greatest principal st rcss was oriented ne-sw. as orogenic movements occurred in the ne hinterland of the newly formed basin, as evidenced by the sedimentary succession from the foraminiferal limestones to flysch, incomplete suc­ cessions are not unusual. in some places different units of the foraminiferal limestones are missing, and else­ where flysch was deposited directly over cretaceous beds (polsak & stktc, 1969; mar1nc:jc, 1986). the fly sch deposits in central istria (from brtonigla to labin) represent the sw part of the fonner tlysch basin with a dinaric orientation (nw-se). through further compression the ne part of the basin was partially con­ sumed by underthrusting beneath the cicarija mountain range, and became part ially involved in its nappe stru­ cture. i i r savudrija ~==~"d"'vigrad • rovinj kolone v.brijunv o despite the intense regional tectonics which resulted in the uplift of the dinarides, the area of wes tern istria suffered no int ense structural -tectoni cal deformat ion. thi s is probably the consequence of deformation of the rl ysch basin which resulted with the early fonnalion of the regiona l underthrusting zone. in this way the rcs istence against the movement of the sw part of the pjatfonn decreased significantly, and it started to under­ thrust towards the ne. while the basic structure of the penin sul a, i.c. sw part of the bas in , remained ra ther undisturbed, the a bducted part was strongly contracted and tectoni cal ly deformed. younger, po st-miocene movements are characterised by a regional stress orient­ ed approximately s-n (ma ticec, 1994), and resulted in the formation of new structures with the charac teris­ tic e-w orien tation of the b-axis. mari nc ic & matlcec (j989, 1991) have con­ firmed the a forementi oned orienta tion of the wes tern istri an structure (b-axi s oriented 35/8) by detailed field investigati ons, and determined the basic orientation of the tectonic coordinates of the larami an phase in the region of lstria. therefore the present structural fabri c f. 0 d d d d 20 km 6 5 4 3 2 1 geolog ia cro<ljica 49/ 1 fig. i geological ~kc !ch map of islri a (modifi ed nfler ihe geological map of sfry 1 :500.000, pllbli~hed by ihc federal gcological lnslilul c, l3elgrade, 1970) wit h ihe lo­ calit ies mentioned in the lext. legend: i) jurllssie; 2) low­ er creillceol1s: 3) upper cre­ laeeous; 4) palacogene fora­ miniferallimes10 llcs and fl y­ sch deposi ls: 5) lnvesl igalcd occurrences of ihe eocene forami niferal limcslo ncs: 6) axis of ihc wes le rn [slria1l antic line. and orientation, as well as the timing of the fina l forma­ tion of thc wes tern istrian ant ic line are well known. however, traditional view of a structurally stable istria, characteri sed by the continuous deposition oj" carbonate platform deposits ovcr the enti re area throug h the c rc­ taceous and subseque nt gentl e fo lding with important e rosion during the la ramian tectonic phase, cannot explain some new di scoveries in stratigraphy and tec­ tonics or western istria. 2. stratigraphic position and characteristics of foraminiferal limestones in the vicinity of sv. lovrec and visnjan fi gure 2 represents a geological ske tch-map of the area ncar sv. lovrec showing the outcrops or the eocene foi'amini fcral limestones, which transgressivejy ove rlie va langinian (fi g. 2, a) and i3 arremian lime­ stones (fi g. 2, b), in the fo rm of a small e ros ional relics. the valanginian deposits are characteriscd by m<llicec. vlahovic. velie & ti.~lj;lr: eocene lime~10ne$ overlying lower crcl:1ccou~ dcpo~ils ... 119 " 0.1 0.2 0.3 km g a lzej 6 fig. 2 lilho!>lraligraphic sketch illap of the sv. lovrec area. legend: 1) valangini an and liauterivian deposits: 2) barremian deposits ; 3) erosional relics of the eocene foraminifcrallimcslone a} overl ying valangin ian, b} overlying barremian: 4) normal geo­ logical boundary: 5) faults: 6) roads. the rhythmical a lternation of light -coloured mudstones wit h pell etal paekstones, and favreina-intraclastic grain­ stoncs containing the following microfoss il assemblage: ep;liiasfopora cekici radoicic, safpil/goporefla isfri­ ai/a gu s ic, s . pra!l/r/ol/i dr agastan, i-ielero­ porei/o pol/cico/corea con rad & radoicic, 1"0/­ so/ikol/ el/a call/pal/el/sis (azema & jafr ezzo), dissocfadella halfter;viana masse, vercorsella lellllis (ve li c & gusic), v. call1posa,,rii (sartoni & crescenti), i' se"dolexli//ariella sa/evel/sis· ci-lar­ ollai s c( a i. , ciloella? f ovrei ci-larollais e( ai., trocholil/o sag illoria arnaudvanneau, t. de/­ phillellsis arnaudv anneau, favreilla f/jegoscl/­ j'is bronn ima ni ,ctc. barremian deposits are reprc­ sented by the alternation of miliolid wackestones, os tra­ cod mudstones, skeletal -peloid-intraclast grai nstoncs and gas tropod-mollu sc grains tones/floatstones (fig. 3a). their age is detemined by the frequent occurrencc of foss il algae and benthic foraminifera: salp;ngoporel ­ /a lii e/ilo e radoicic, s. iiiliehihergii (lorenz), s. genevellsis conrad, prafur/onelfa danifovae (rad­ oicic), cy/illdrol'ore//o il'allovici (sokac), /-llllllie//o b a fig. 3 $v. lov rec b tocality: a} a photomic rograph of sketclal ­ peloid-int raclas t grainstone of barremian age, x6.5; b) a pho­ iolllicrograph of the eocene foramini feral limestone, x4.5. pllpl/olensis sokac, c/ypeino so/kol/i c onrad & radoicic, c. solllalica conrad c( ai., sobolldio li/inlllo (hofker), nova/esia dislorla arnaud­ vanneau, n. cornllcopia arnaud-vanneau , d ebarina haholfllercjlsis fourcade et a i. , p.';ellc!of/ ­ wiiijl%cl/lino sp., etc. in the samples of the palaeogene limestones thc fol ­ lowin g microfossil assemblage has been de termined: numml/litcs sp., assililla sp. , discocyclifla sp. , lefilicli­ laria sp. , rotalia sp. , ?fabiania sp. , ?corallinaceae or ?a cervulilla (i.e. red algae or inc rusting ro raminifera, indeterminable because of the recrystallisation and par­ tial dolom itization of the sediment) , as well as c ri noid plates and relics of bryozoans, molluscs and corals . such an assemblage indicates a lute tian age, and can be comparee! with the uppermost part of the numnhllite beds elsewherc in the adriatic carbonate platf orm. it should be mentioned that fora minifera are speeirically indeterminable because of the intense wea the ring and reerystallisation they arc mostly di ssolved, and only skeletal vo ids are preserved. the limestones are intensely rccrystallised with late diageneti c dolomitisa120 ..... : ..... . .... .. [j2 ~5 fig.4 geological sketch map of the area near visnjan (simplified after polsak & sik1c, 1969). legend: i) lower cretaceous limestones; 2) eocene foraminiferal limestones; 3) studied local­ ities; 4) faults; 5) roads. lioll of skeletal-peloid wackcstonc/packstones to floa1stones, composed of mechanicall y destroyed bioclasts and more or less recrystallisecl nne-grained peimicrilic matrix (fig. 3s). grains range in size [rom peloids and bioclasls smaller than 1 illm to foraminifera tests larger than 15 111111. according 10 the basic geological map of the rov­ inj sheet (polsak & sikic, j 969) outcrops of the eocene foraminiferal limestones closest to sv. lovrec were found ncar visnjan (fig. 4). among several out­ crops presented on this map two localities, labinci and markovei, were investi gated in detail for the present study. at both localities it has been determined that the eocene beds arc overlying hauterivian deposits. in a detailed measured column ncar labinci (fig. 5) peritidal mudstones, skeleta l waekestones and pack­ stones contain the following microfossil assemblage: green algae clypeilla solkani conrad & radoicic and salpingopore/fa al/nula/a carozzi, and forami­ nifera campane/filla capliensis de castro, indica­ ting an upper hauterivian age (fig. 5a). in the palaeo­ gene foraminifcral packstonc/grainslones (fig. 5b), the following assemblage indicating a lower to middle eocene age has been determined: acervulillg ogorrnani (douvillel), sphoerogypsilla globllia reiss, niiiii­ ljiulites sp., dermatolitholl sp., alveolil/a sp., lenticugeologia croatica 49/1 laria sp., rotalia sp., gyroidina sp., asterigerina sp., cibicides sp., as well as skeletal remains of bryozoans, molluscs and corals . near markovei village the hauterivi an limestones with sa/pingoporel/a annu/ala and campane/lu/a capllensis (fig. 6a) arc overlain by the eocene fora­ miniferal limestones (fig. 6b) containing a rich micro­ fossil assemblage: acervlllina ogormani, a. linearis (hanza wa), cavilierina valiellsis (ruiz de ga­ ona), splwci'ogypsina globu/a, discocyc/ina agllstae (van der weijden), d. selia (d'arci-ilac), d. radians (d' arci-liac), peysollelio allliqllo joi-in­ son, alveolilla levanlilla hottinger, miniacino liiallicamerala (scheibner), elhelia alba (pfend­ er), nlimmulites sp., assi/ina sp., asterocyclina sp., cihicides sp ., notalia sp., orbitolites sp ., textularia sp., gyroidina sp., lenticll/aria sp., spirolilhon sp., litho/amnillm melobesillm (foslie), lithophyllum sp., and bioclasts of crinoids, molluscs and echinoderms. 3, synsedimentary tectonics in the cretaceous deposits of istria cretaceous orogen ic movements in the mediter­ ranean region affected the adriatic carbonate pl atform. to define these compressive movements it is necessary to explain the relationship between the continuous regional tectonism and the sporadically discernible con­ sequences of the synsedimentary deformation. the period of dcformation caused by the regional stress of the same orientation represents a tectonic cycle. ccssation of the stress results in cessation of thc deformation, and lhe change of its orientation results in new deformation, i.c. a ncw tcctonic cycle. the process of deformation is usually gradual, bcing composed of the individual episodes of increased tectonic activity (i.e. parts of the tectonic cycle tectonic phases), and relat ively calm periods between them. a tectonic cycle is defined by its duration, the orientation of its tecton ic coordinates (the greatest principal stress and position of the b-axis), and direct ion of the tectonic transport. hence, it is recognisable in time and space. its cessation is marked by the maximum defonnation. therefore the deformation represents a cumu lative process during cac h phasc in a cycle deformation being added to the conner phase. consequently, in consideration of thc tec­ tonic activity in the cretaceous of istria we have to start from its youngest records working backwards towards the older ones with the same tectonic coordinates, as follows: a) bauxite deposits in istria arc most commonly sit­ uated above the cenomanian deposits. bauxitic materi­ al had fihed depressions in the relief formed by the ero­ sion of junctions of lhe youngest, post-cenoma nian joint systems (marincic & ma tlcec, 1989) with orientations corresponding to hoo and oko joint systems of the western istrian anticlinc (i .c. nne-ssw and ese-wnw). maticcc, vlahovie, velie & tisljar: eocene limeslones overlying lower cretaceous deposits .. agel lithology i description " m -w """ -"", --c ,""" "0" foramini feral "00 c_ packstjgrainst ~til9 .... lb·s palaeokarslified. .... lb·4 brecciated mudstone light·coloured mudstone c oj ";; .~ s '" i ui 0 e ostracod q; mudstone cl. .... lb·3a. lb-3b cl. .... lb·zc peloid ::j .... lb·za. lb·2b mudstone covered .... lb·ia. l(l·hj fig. 5 detailed geological column at the labinci locality; a) a pho­ tomicrograph of the upper hauterivian limestone with sa/pingo­ porel/a (liilll/fafa carozzi and call/pallettuta capl/cll.l"i.l· de castr o, x20; b) a photomicrograph of lhe eocene forami­ niferal limestones (bioclastic packstone) containi ng nummulilid s and alvcolinids, x5.5. b) facies differentiation that has been recorded at the beginning of the cenomanian in thc arca of istria is a consequence of the synsedimentary, compressive tec­ tonic activi ty (vla hovic et ai., 1994; tisljar ct a i. , 1995). in southcrn istria ncar banjole, a tilting of the platform towards the ese has been determined. the distribution of the contemporaneous different facies in northern 1st ria , near savudrija, is also characterised by the same ori entation. the lateral extent of the faci es belts, as well as the orientation of ripple-axes in the cenomanian (nne-ssw), corresponds to the orienta­ tion of the western tstrian anticline. the highest parts of the struct ure probably remained emerged until the transgression in the palaeogene: in central istria bauxite deposits overlie either albian deposits (prhat) or midfig. {) markovci tocality: a) a photomicrograph of the upper hau­ (crivian limestone con1aining solpingopore1la anflutalo caro­ zz i and coljlpolleflllla capucl/sis de castro, x35; b) a pho­ tomicrograph of the eocene foraminiferal limestones (bioclast ic packstone) with nllltlmlllitids, discocydinids, etc ., x5.5. 121 b a b a 122 geologia cro:l1ic0l49/1 palaeogene santonian coniacian turonian 20 km albian aptian barremian hauterivian valanginian berriasian marusiti prhati visnjan sv. lovrec a sv. lovrec b kelone mrlera fig. 7 a sc ilcli1<llic correlation showing the position of eocene forarnini fera limestones overlying different stratigraphic levels of the cretaceous (valangini;hl 10 santonian). die to upper cenomanian deposits (pazin area polsak & s ikic , 1969) , wh il e in northern islria (i3l1zel anei karojba drobne, 1977; marus ici yelic & ylahoyic, 1994) palaeogene foraminife­ ral limestones lie on the upper cenomanian beds. c) 'fhe complete area of western istria was emergent during the major part of the aptian, and during the lower albian. there are no clear structural indications as to the coordinates and character or the tcctonics, but the influence of the synsedimentary tectonics is evi­ denced by the palaeogeographical situat ion in this peri­ od or the lower cretaceous in the iso'ian part of the platform, in the central pan of the western istrian structure (baderna heraki area) the emcrsion started during the latc barrem ian , and lasted un t il the late albian , on the limbs of the structure deposition contin­ ued in the early aptian, but with latera lly distinct dif­ ferent facies: in the se part (dvigrad kanfanar veli brijull area) massive lagoonal oncolite micl'ites were deposited, while in the nw part (heraki cervar area) there are limestones originating from the shallow-water, higher energy environments. over the major part of the structure emersion started during the early aptian, but in (he dvigrad kanf'anar area deposition was prolonged even to the basal part of the late aptian. all these areas were nooded by the transgression in the laic albian (yelic el ai., 1989; tisljar cl ai., 1995). d) our recent investigations in the kolone cove (se of rovinj ) indicate synsedimentary tectonics in the hauterivian, with the orientation of the greatest princi ­ pal stress corresponding to the aforementioned episodes (c. 308°). the constant orientation of the tectonic coordinates of the aforementioned movements during different peri­ ods of the crefaceous indicate that they belong to a sin­ gle tcctol/ic cycle, with activity evidenced sporadically from the hauterivian to the end of the cretaceous. 4, palaeogeographical considerations eoccne foraminiferal limestones transgressively overlie deposits of different stratigraphical levels (fig. 7). in addit ion (0 the described valanginian and bar­ remian examples near sv. lovrec and those of (he hauiv1aticec. vlaliovie. velie & tisljar: eocene limestones overlying lower crdaceoll~ deposits ... 123 terivian near visnjan, tunis et al. (1994) reported 011 nummulite limestones and breccias in contact with the hauterivian limestones in the kolone cove (se of rov­ inj). from previous studies there are data on palaeogene deposits overlying albian carbonates north of visnjan and cenomanian sedi ment s in central and northern lstria (polsak & siklc, 1969; drobne, 1977), as well as the senonian of southern istria and in the vicini­ ty of labin (polsak, 1967; stkic ct a\', 1969), besides three very important long-lasting emersions influencing 1st ria (kimmeridgian late tithonian, bar­ remian/early aptian late albian, and cretaceous palaeogene) shan emcrsio ns were so frequent during some periods (e.g. hauterivian, barremian) that they represent a specific characterist ic or the facies. parase­ quences, i.e. shallowing-upward cycles , usually ended by emersion, arc commonly composed of clayey mater­ ial and frequent black-pebble breccias. considering the ract that during these periods there arc traces of dinosaur activity, the palaeoenvironment would proba­ bly represent a wide coastal zone surrounding the land, with peritidal deposits and numerous coastal swamps. during periodic relative sea-level oscillations black, reductive swamp deposits were reworked and rede­ posited by tidal channels in neighbouring intertidal and shallow subtidal environments. in western 1st ria there are several localities with dinosaur footprints which span a broad st ratigraphic range (late barrem ian, late albian and late cenoman­ ian) and bone remains (late hauterivian/basal barremi­ an). dalla vecchia & tar lao (1995) made some very interesting palaeogeographic interpretations: on the basis of the available data they concluded that 1110st of the anima ls were carnivorous, i.e. they needed a land area large enough to enable their survival by sup­ porting herbivorous animals, which need huge amounts or plant materi al, as well as fresh water. it sh ould be emphasised that the environments where the footprints were found, with conditions favourable for thei r preser­ vation, were not a habitat of the dinosaurs . they lived on the land, and probably only transgressed across the coastal areas. with regard to the repeated occurrence of root prints which span a lengthy stratigraphic range, it may be concluded that ist ria rcpresented a suitable area ror their colonisat ion and existcnce during the creta­ ceous. sincc the apical parts or the western istrian anti­ cline represented the land arca with a changing surraee due to the interaction of tectonic and eustatic factors, it is poss ibl e to suppose at least occasional connection with neighbouring larger continental areas. tn the area or ist ria there are two levels of bauxite deposits: between the oxfordian and upper tithonian, and cretaceous and palaeogene. whi le the footwall of the jurassic bauxites is of the same age in all localities, the rootwall of the younger bauxites belongs to the dif­ ferent levels of the cretaccous mostly to the cenoma­ nian, but in the area of prhat to the albian . this indica­ tes that the bauxitic material was accumulated in the de­ pressions of subaerially exposed rocks of different age. aforementioned findings of the bauxite deposits on the albian and cenoman ian, as well as palaeogene foraminiferal limestones on the lower cretaceous con­ siderably alters the probability of the intense erosion or the cretaceous deposits , which was proposed in the for­ mer interpretations. lack of the younger cretaceous deposits was interpreted as a consequence of significant erosion after the santonian. howeve r, discovery of palaeogene deposits overlying the valanginian, hau ­ terivian and barremian beds indicate the absence of the upper part or the lower cretaceous and complete upper crctaccous beds prior to the palaeogene trans­ gression, which would correspond to more than a 2.000 m thick sequence of carbonates deposited in the neigh ­ bouring areas or southern istria. this fact indicates on a very low possibility that during the cretaceous/palaeo­ gene transition huge amount of deposits, of laterally variable age (the footwall or the palaeogene deposits ranges from the valanginian to the santonian/campan­ ian) were eroded without any relics, and without any evidence of intense tectonics. \vithout excluding some su baerial erosion, or possibly somewha t condensed deposition, we consider that in the discussed areas of istria, the major part of thc cretaceous deposits was not deposited, as a consequence of thc relatively mild, but during the cretaceous continuously present synscdi ­ men tary tectonics. consequently, these facts indicate that the lack of the upper cretaceous and, partly lower cretaceous deposits in western istria is probably lhe consequence of a long-lasting phase of terrestrial expo­ sure in istria rathcr than the subsequent in(ense erosion of a completely depositcd sequence. 5, palaeogeologlcal evolution of western istria through the cretaceous and palaeogene occurrences of the eros ional re lics of the palaeo­ gene limestones on the different stratigraphi cal mem ­ bers of the lower cretaceous deposits of lstria, as well as thc other racts presented in this paper enable modifi ­ cation of the traditional interpretations of the tectogene­ sis of lstria . contrary to th e former opinion that th e anticline structure of the peninsula is a consequence of a single tec(onic act at the end of the cretaceous, it may be concluded that istria was subjected to gentle, but dis­ tinct tectonic movements during the major part of the early and the complete lat e cretaceous. these move­ ments led to important palaeogeographic changes, since in the shallow-water environments of the carbonate platform even small elevations result in an entirely dif­ ferent facie s distribution, and the es tablishmcnt of rather spacious land arcas (fig. 8a, b). the extent of the land was changing during the cretaceous, depend­ ing upon the relation bet ween the synsedimentary tec­ tonics and the eustatic changes; therefore the position of the shoreline was variable (fig. 8c). the land repre­ sentcd a good habitat for dinosaurs, since in the border124 ing areas probably large swamps with flourishing vege­ tation existed. sporadically these animals, (most likely during their searc h for food ) went to the marginal marine environments, w here they left their traces in a soft sediment. during the sporad ic episodes of sea-level ri se there was probably a partial floodin g of the inland area of the wes tern lstrian anticline , e.g. in the dinarides there is a regionally recorded drowning of the platform in the late cenomanian and early turonian cousic & jelaska, 1993). as the apical parts of the structure represented the emerged area, during the sea-level rise a probably relatively thin succession of sedim ents was deposited in the marginal parts, which was eroded dur­ ing subsequent sea-level fall (fig. 8c). on the basis of cu rre nt know ledge, the only ev i­ dence of flooding of the inner part of the uplifted, inner part of the pl at form, are outcrops of th e palaeogene foraminiferal limestones mentioned in this paper. their existence should be analysed in the light of the palaeo­ geographic situation in the lstrian part of the adriatic carbonate platforrn during the palaeogene. due to the change of the regional stress orientation, i.e. the begin­ ning of the new, tertiary tectol/ic cycle, a sedimentary basin of dinaric strike (nw-se) was formed. fora­ miniferal l imestoncs were deposited in its marginal parts, whi le in the deeper, central parts flysch deposi­ tion took place (fig. 8d). during the episodes of rela­ tive sea-level rise the inner parts of the western istrian anticline were flooded, as evidenced by the deposition of the foraminiferal limestones. thi s, sw slope of the basin represented the source area [or part of the calcare­ ous material in the flysch deposits, and babic et a1. (1995) have determined palaeotransport directions towards the n-ne. it should be emphasised that the preservation of the foraminiferal limestones on the old­ er cretaceous deposits after prolonged subaerial expo­ sure represents an exception, not a rule. anyway, it is to be assumed that additional similar findings will be recorded during further detailed work. it is vcry important to bear in mind that istria repre­ sents (due to the relatively weak disturbance by the younger tectonics), a very suitable area for the study of the geological history of the adriatic carbonate plat­ form during the mesozoic. the described dynamics of the cretaceous events could also be expected therefore in the neighbouring areas, since there is a common absence of at least part of the upper cretaceous deposits (e.g. the islands of cres, krk, sv. grgur, prvic and goli otok, as wcll as on part of the cicarija ml). therefore, during further investigations special atten­ tion should be given to the palacogeographic aspect. geologia croi1tica 49/1 6. conclusions on the basis of the presented data and their discus­ sion the following results importa nt fo r the interpreta­ tion of the geological evcnts which oecured during the cretaceous and tertiary in western istr ia should be emphasised: i ) near sv. lovrec previously unknown erosional relics of the eocene foramini feral limestone were discovered overlying valanginian and barrem ian limestones. 2) the footwall of the relics of the eocene fora­ miniferal limes tone near visnjan is composed of the peritidal mudstones and wackestone/packstones of haute riv ian age. a s imilar situation occurs in the kolone cove se of rovinj, where the eocene foraminiferal limestone is in contact with the hau­ terivian limestone. 3) t ecton ic activ it y (i.e. re lative uplift caused by the gentle fo lding and/or faulting) and eustatic changes (i .e. the sea-level fall) has produced frequent emer­ sions of variable duration during the lat e jurass ic and cretaceous: in the kimmeridgian/tithonian, hauterivian, barremian and aptian/albian. 4) the emerged areas were inhabited by dinosaurs, during the s trati graph ic range from the late hau­ terivian to the upper cenomanian (at least), as ev i­ denced by rel ics of their footprints and bones. 5) facts stated in 1-4 were determined in the wider area of the western l strian anticline, and arc closely related to the timing of its formation and later relat­ ed geological events. 6) thc beginning of the formation of the structure took place earlier than in the maastrich tian : it is dete r­ mined by the palaeotectonical parameters deter­ mined in the hauterivian and cenomanian, and reg­ istered in the aptian and albian. 7) the orientation of the above mentioned palaeostruc­ tural clements formed by synsedimentary tectonical activity during the early and late cretaceous of istria is in agreement with the elements whose for­ mation was formerly attributed exclusively to the maastrichtian age in istria, as well as in the other regions of the adriatic carbonate platform. 8) bauxites from the footwall of the palaeogene lime­ stones were deposited in the palaeorelief of the cenomanian and albian limestones. this fact toge ther with the transgrcssivc nature o/" the eocene foraminiferal li mestones on the valanginian, hau ­ terivian, barremian, albian and cenomanian deposits exclude the possibility of the continuous deposition of a complete upper cretaceous sequ­ ence, and its subsequent erosion prior to deposition of the foraminiferal limestones, especially as there should have been eroded laterally different amounts of material (from 1.000 to 2.000 m) without any trace, and without any evidence of intense tectonics. maticcc. vlahovie. velie & tisljar: eocene limestones overlying lower cret~ceous deposits .. ;;f(~n ~ a; ;t~~~ __ ~!~~-~~ ____ ~~ __ -l~~ 1 4 ±o sea-lev()1 ==""==="'i",,'"-::~,-=""?'=c::c/ ±o sea-level ) ( ±o sea-level legend: ;t 5 125 eocene o santonian c cenomanian b neocomian a rig. s a schell1<1tic dmwing rcpresenting tile p;daeogeological dynamics of western htria during the cretaceou~ and palacogclll:.'. a) the initial stage of formation of the western ]strian structllre; b) relation between tile shallow-water environments and thc land areas in the complex geomo rphology of the structure caused by tectonic uplift; c) decrease of marine deposition during the extensive ernersion; d) formation of the flyseh basin by the refolding of the cretaceous anticli ne; legend: i) lower cretaceous deposits: 2) cenomanian deposits: 3) turonian ­ santonian deposits: 4) palaeogene foraminiferal limestones and flysch deposits: 5) orientation of the regional stress during the cretaceous lcc/ollic cycle: 6) orientation of the regional stress during the tertiary tectonic cycle. 126 analysis and interpretation of the presented results facilitate the following conclusions on the pajaeogeo­ logical evolution of the western lstria: • the mutual relations of the cretaceolls and palaeo­ gene stratigraphic linils , as well as tile otlier men­ riolleel data indicate lhal ill the central pari of the s{l"uc/ure yollnger early cretaceous and late creta ­ ceolls iinits were //o! deposited as a cof/sequence of the prolonged subaerial exposure. • the loran/ian tec/ollic phase, which is in fhe dinar­ ides attributed 10 be of the youngest cretaceous (maastrichtian) and oldest palaeogene age , at least ill the area of the western isffian anticline repre ­ sci/is only one of the tectonic phases within the cre­ taceolls tectonic cycle, characterised by fhe same tectollic coordinates sillce fhe neocomian. acknowledgement this paper was written as a result of work undertak­ en for the geological map of the republic of croatia (scale i :50.000), financed by the ministry of science and technology of the republic of croatia. we are gratcful for thc material support which has been provid­ ed by the institute of geology, zagreb. also, we are grateful 10 dr. vlasta cosovic for her determination and biostratigraphical interpretation of the eocene lime­ stones and dr. branko sokac for his determination of fossil algae. we would especially like to thank prof. dr. ivan blaskovic, dr. bojan ogorelec. prof. dr. giovanni battista carulll and dr. julie robson for their suggestions, comments and critical reviews of the manuscript. geologia croatica 49/1 6. references babic, lj., zupanic. j. & juracic. m. (1995): supply from an outer carbonate platform to the fore­ land basin of the coastal dinarides: the pazin fly­ sch basin (eocene, croatia).in: vlahovic, i., velic, i. & sparica. m. (eds.): 1. hrvatski geo­ loski kongres (first croatian geological congress), zbornik radova (procccdings), 1,43-45, zagreb. dalla vecchia, f.m. & tarlao, a. (1995): dinosaur evidence in the cretaceous of lstria (croatia). in: vlahovic. i., velic, i. & spa­ rica, m. (eds.): 1. hrvatski geoloski kongres (first croatian geological congress), zbornik radova (proceedings). i. 151-154. zagreb. drobne. k. (1977): alveolines paleogenes de la slovcnie et de l 'istrie.schwciz. pahiont. abh ., 99, 174 p., basel. gui:jc. i. & jelaska. v. (1993): upper cenoman­ ian-lower turonian sea-level rise ancl its conse­ quences on the adriatic-dinaric carbonate plat­ form. geol. rundsch. , 82. 676-686. marincic. s. (1986): fhs.5. skup sedimento loga jugosj., voclic ekskurzije , 27, brioni. marin cic, s. & ma ticec, d. (1989): kolapsne strukture u boksitnim jamama istre (collapse struc­ tures in bauxite pits of istria). geol. vjesnik, 42, 121-131, zagreb. marincic, s. & ma ticec, d. (1991): tektonika i kinematika deformacija na primjcru istre (tectonics and kinematic of deformations, an istrian model). ­ geol. vjesnik, 44, 257-268, zagreb. maticec. d. (1994): neotectonic deformalions in western istria, croatia.geol. croat., 47/2, 199204. polsak, a. (1967): osnovna geoloska kart a sfrj, list pula 1:100.000. l 33-112.inst. geol. istra7 .. zagreb (1963). say. geol. zavod. beograd. polsak. a & sikic. d. (1969): osnovna geoloska kart a sfrj, list ravinj 1:100.000. l 33-100.-lnst. geol. istrai. zagreb (1957-1963), sav. geol. zayac!. beograd. polsak, a. & sikic, d. (1973): osnovna geoloska karta sfr.t. tumai' za list rovinj i: 100.000, l 33100 (explanatory notes for the rovinj sheet). inst. geol. istraz. zagreb (1963), say. geol. zavod , beograd, 51 p. sikic, d., polsak. a. & magas, n. (1969): osnovna geoloska karta sfrj, list labin i: 100.000. l 33101.insl. geol. islraz. zagreb (1958 1967), sav. geo l. zavocl, beograd. tisljar, j., vlahovic. 1., maticec, d. & vellc, 1. (1995): platformni facijes i od gornjeg titona do gornjeg alba u zapaclnoj istri i prijclaz u m:lticee, vln.hovie, velie & tisljar: eocene limestone.~ overlying lower cretaceous deposits ... 127 tempestitne, klinoformne i rudistne biolititne faci­ jese donjeg ccnomana u juznoj istri (ekskurzija b) (platform facies from the upper tithonian to upper albian in western istri a and transition into tem­ pestite, clinoform and rudist biolithite facies of the lower cenomanian in southern istria (excursion b )).· in: vlahovic, i. & vellc, 1. (eds.): 1. hrvatski geoloski kongres (first croatian geological congrcss), vodic ckskurzija (excursion gui de­ book), 67·110, zagreb. tunis, g., sparica, m. & venturini, s. (1994): lower cretaceous dinosaurs from valle (lstria, croatia): stratigraphical, sedimentological and palaeoenviromental problems. 14th internat ional sedimentological congress, recife 1994, abstracts, s5, 14·15, recife. vellc, i., tisljar, j. & sokac, b. (1989): the var iabil ity of thicknesses of the barremian, aptian and albian carbonates as a consequence of chang­ ing depos itional environments and emersion in western istria (croat ia, yugoslavia).mem. soc. geol. it., 40 (1987), 209·218. velic, i. & vlahov ic, 1. (1994): foraminiferal assemblages in the cenomanian of the buzet-savu­ drija area (northwestern istria, croatia) .oeo l. croat., 47/1 , 25-43. vlahovic, i. , tisljar, j. & velic, i. (1994): influence of synsedimentary tectonics and eustatic changes on deposition of the cenomanian platform carbonates in istria (western croatia). geo logi c medilcrraneenne, 21/3-4, 189·193. manuscript received july 7, 1995. revised manuscript accepted may 27,1996. i geol. croat. i 50/2 1225 230 i 6 figs. 3 tabs. zagreb 1997 review of the results of morphometric and morphogenetic analyses of early pleistocene micromammals and upper pleistocene cave bears in croatia maja paunovic and ooi'dana jambresic key words: morphometry, morphogenesis, microcvo­ lulion , stratigraphy, cave bear, micromammal s, pleistocene, croat ia. abstract due 10 lhe large number and visible morphological variab ility of skeletal paris of ihe early pleistocene micromammals and upper pleistocene ursids we utilised morphometric, morphogenetic and sta­ tistical analyses in order 10 determine and process the material. the results indicate rapid microcvolulionary processes which arc rcllcc!cd both in variations of the characteristic parameters of particu lar skele­ tal parts , and their morphology. the early pleistocene age of the bone-breccias discovered along the adriatic coast was confirmed by the morphogenetic analy ses of micromammals, with reference to geochronolog ically important arvi­ col ids: the fauna fro m razvode ncar knin comprises arvieolids char­ acteristic of the lower early pleistocene, the fauna from tatinja dra­ ga near karlobag comprises species typical for the middle early pl eistocene, while the fauna from podumci ncar uncsic is of la te early pleistocene age. the results of the analyses of teeth and metapodial bones of the cave bears from (he upper pleistocene deposits in vindija cave, veli­ ka pecina and veternica cave (nw croatia) are expressed as morpho­ dynamic indices, namely, the frequency of the morpho types occur­ rence indicates the existence of an ijl(ermediate type (?subspecies) within the phyletic lineage ursli.l· denillgeri ur.l"iis ,1"{jefaells, which appeared during the riss glacial and riss/wlirm interglacial, and a lack of deposits of that particular age in vcternica cave and velika pecinil. 1. introduction for large quantities and variability of fossil material the multifarious options for data processing provided by computer technology has helped to make morphometry a very commonly used method in thc palaeontological analysis of vertebrates. additional morphogenetic stud­ ies which also enable the determination of relative geo­ logical age of the material and microevolutionary trends, have been carried out for many assemblages, namely families and/or taxa. in croat ia, such investiga­ tions have intensified in the 1980 's, when processing of croatian academy of sciences and arts, institute for quaternary palaeontology and geology , ante kovacica 5, hr-ioooo zagreb, croatia. kljucne r1jecl: morfomctrija, morfogencza, lllikro­ evolucija, stratigrafija, spilj ski medvjed, mikrosisa­ vei, pleistocen, hrvalska. saietak zbog brojnosti i uocene morfoloske varijabilnosti skeletnih dijclova donjopleislocenskih mikrosisavaca, odnosno gornjopleisto­ ccnskih ursida, prilikom dctenninacijc i obrade matcrijala koristene su morfometrijske, mor fogenetske i stalisticke analize. rezullati su ukazali na brze mikroevolucijske procese koji su se odrazili kako u promjenama mjerenih karakterislicnih parametara pojedinih skeletn ih dije lova tako i na njihovu morfologiju. pretpostavljena donjopleistocenska stmost kostanih breea knje su nadene duz obale jadrana potvrdella je morfogenetskim anal izama fau na mikrosisavaca u kojima dominiraju geokronolosk i va7.ni arvi ­ kolidi: fauna iz razvoda kod knina sadrzi a rvikolide karaktcristicnc za rani donji pleislocen , ona iz tatinje drage kod karlobaga vrste tipicne za srednji donji pleistocen, dok je fauna iz podumaca kod uncsica kasno donjopicistocenske starosti. rezultati analiza zuba i metapodija spiljskih medvjeda iz gornjo­ pleistocenskih naslaga sp ilja vindija, velika pecina i veternica (sz hrvatska) izrazeni morfodinamskim indeksima odnosno uce s!a lo­ stima pojava morfotipova ukazuju na postojanje prijelaznog varijeteta (?podv rste) u razvojnom nizu ur,\"lis dellillgeri urslls spe!aells koji se javlja lijekom glacijala r iss i inlerglacijala ri ss/wlirm, odnosno nedostatak naslaga ove starosti u spiljama veternica i velika pecina. the upper pleistocene bears from vindija cave, then veternica cave and velika pecina (nw croatia) began as well as analysis of the early pleistocene bone-brec­ cias at razvodc, tatinja draga and podumci (s croatia). the large quantity and variability of the studied material has so far enab led the establishment or illor­ phogenelical schemes for particular taxa (e.g. ursus spelaelfs, micro/us), thus also allowing a relative dating of the rest of the vertebrates from deposits of undefined or questionable age with respect to the method "count­ ing from the top". this paper was presented at the scientific meeting dedicated to the 80th anniversary of the life of professor milan herak, held on march 5th, 1997 in zagreb 2. localities 2. i. early pleistocene the early ple istocene bone-breccias arc located in karst ic fissures along the adriatic coast: at tatinja dra­ ga near karlobag, razvode near knin, and podumci ncar uncsic (fig. 1), the bone-breccia matrix from tatinja draga and podumci is reddish-brown in colour, reflecting a tem­ perate climate during the deposition, while the yellow­ ish-green sandy clay matrix from razvode was depo­ sited under colder climate conditions . the faunal asse­ mblages arc typical for the early pleistocene and there arc no signs of sed imentary recording of fossils trans­ portation (see: malez & rabeder, 1984; pauno­ vic & rabeder 1996). 2.2. upper pleistocene the vindija cave is located near varazdin (fig. 1) in the sem i-mountainous terrain of hrvatsko zagorje. the cave entrance lies at an altitude of 275 m above sea leve l on the slopes of mt. ravna gora, and is a single large chamber, 50 m long, 28 m wide, and more than 20 m high. approximately 12 m of stratified deposits were inves ti ga ted and divided into 13 distinct stratigraphic units designated a (youngest) lo m (oldest). the layers m and l appear to date to the riss glacial, unit k cor­ relates with the riss inte rglacial (eemian), layers j-d encompass the last glacia l (wi..irm=weichselian), while the upper three layers (c-a) are post-pleistocene (sec: paunovic, 1988). all pleistocene faunal asse­ mblages found at vindija cave are dominated by cave bear remains. the velika pecina near varazdin (fig. i) is dividcd into three separate chambers. of these the first chamber is the largest measuring 18 m in brcadth, and approxi­ mately 3 m in high, while the other two chambers are much smaller. the quatcrnary sediments are over 12 m thick and separated into 16 levels (a-p). after malez ( 1986) the layers 0-1 are correlated to the riss/wlirm interglacial (eem ian ), layers k-e encompass the last glacial (wlirm weichselian), and the upper four (d-a) are post-plcistocene. all the strata contain skeletal rem­ ains of quaternary mammals, with a predominance of eave bear. the vetcrniea cave near zagreb (fig. 1) is the lon­ gest cave in nw croatia with over 10 km of passage­ ways and canals. the entrance chamber is about 15 in long, 7 m w ide and 5-8 m high. beginning from the nw corner of the entrance chamber, the " left hall " extends for 14 m and is 3-7 m wide. quaternary sedi­ ments were excavated in the cntrance chamber and "left hall". in the most complete profiles, ii geological lay­ ers were identified (a-k) which were deposited from the riss glacial period until the holocene. after malez (1965) the lowest layer k did not contain any palaeonto­ logica l or archaeological remains. the layer j was dated fig . i location map. upper plei slocene localities: i) vindi ja; 2) velika pecina; 3) veternica. early plei stocene locali1ies: 4) tati­ nja draga; 5) razvode; 6) podumci. as riss/wurm interglacial, the layers i-e as glacial wi..irm, and the upper four layers (d-a) as post-glacial. all pleistocene faunal assemblages found at the veter­ nica cave are dominated by cave bears. 3. methods in the process we app lied morphometric and mor­ phogenetic methods described in the literature (e.g. chaline, 1972; rabeder, j983; malez & rab­ eder, 1984; paunovic, 1988; krklec, 1995) in accordance with the basic condi tions necessary for the reconstruction of functional-morphological changes in mieroevolutionary trends (carroll, 1988; boula­ rd,1993). 4. results 4.1. micromammals from earl y pleistocene bone-breccias the determination of micromamrnals from early ple istocene bone-breccias that were considered not to be synchronous, yielded a large number of endem ic ta­ xa in the fauna of southern croatia (tatinja draga, raz­ vode, podumci) and also geochronologically important arvicolids (tables 1-3). from podumci near unesic, a site known since 1930 (sec: malez & rabeder, 1984), extens ive material discovered by malez led to new knowledge of the genera episoriculus, microtus, pliomys, lagurlls and dijlaromys, as well as to the stratigraphic classifi­ cation of the podumci fauna as being of late lower pleistocene age (op.cil). four new taxa were estab­ lished: ep isoriculus then ii, rete/lomys podumcensis, microtus then!! and lagurl/s arankae podumcensis , / / / palillovic & jambrcsic: review of the results of morphometric and morphogenetic analyses ... 227 localities mammalia razvode tatinja draga podumci talpa minor + + talpa europaea + sorex runtonensis + + episoriculus thenii + + beremendia fissidens + + crocidura kornfefdi + + rhinolophus ferrumequinum myotis bechsteini myotis blythi hypo/agus brachygnathus lepus sp. + + marmora sp . + sciurus sp. + gus sackdillingensis + + reteliomys podumcensis allocricetus croaticus bursae microtus praehintoni ratticeps mimomys malezi + + mimomys savini + + mimomys pusillus + + dinaromys da/matinus + + p/iomyscf. schemfeldensis + pliomys simplicior bolkayi pliomys d. hollitzeri lagurus arankae + apodemus d . sylvaticus + apodemus mystacinus epimelas + (ma lez & rabeder, 1984) . according to cha­ line (1972), rab eder (1981), kowalski (1992) and the presence of successive stages of the evolutio­ nary lineage of the microtus-species can be in terpreted as local evolutionary trends and therefore the new estab lished montepeg lian microtus-thenii-zone is also of loca[ significance (malez & rabeder, [984). + + + + + + + + + + + + +? + + + + + bursae thenii + + + + bolkayi + podumcensis + table i list of lower pleistocene + fos sil mammals (aner paunov ic & radeder, 1996). taxa razvode tatinja draga podumci allocricetus 31 3 4 mimomys 3 4 1 pliomys 14 5 36 dinaromys 0 1 6 lagurus 0.1 76 21 microtus 31 7 29 apodemus 20 4 3 others 1 0 0 total 166 877 868 the fauna of razvode ncar knin contains arvicol ids (microllfs cf. jjraeliil/(olli, pliomys simpliciorlhollirzeri, lvlimomys pusilllls) which ind icate an early pleistocene age. a new species of hamster (a//ocricetlls croat/clls) is to be emph as ized (pa unovic & rabeder, 1996). the fauna of tatinja draga near karjobag con­ tains many more ind ividua ls and is also dominated by arv icolids (lagl/rl/s arallkae, pliolllys bolkayi, plionlys liolfilzeri, dil/aromys da/matillus, mimomys savilli, m. pl/silllls). among these remains a new species microtus eoml/iceps was determined (paunovic & rabed­ er,1996) . t abl e 2 frequenc ies of rodent taxa (mostly <inc] m 1) ill % (after rrom these results the following conclus ion s may be drawn: three species of the genus microtus obviously belong to the lower pleistocene ancestral group (malez & ri\b eder,1984). the lower evolut ionary level of the majority of deter­ mined taxa is also confirmed by indices and the fre­ quency of morphotypes (malez & rabeder, [984; paunovic & rabeder, 1996). paunovic & rabeder, 1996). the determination of the genera laglln/s (type arajlkae)' and mimomys (species pusillus and savinii) favour a lower pleistocene age. at the same time the metrical data and molar morphotypes of the genus lagurlls (fig. 2), as well as the genus pliol1lys (ri g. 3) indicate that the fauna from razvode (lower early pleistocene) is older than the fa una from tatinja dra­ ga (m iddle early pleistocene), which is somewhat older than the fauna from podumci (late early pleis­ tocene) (table 3; paunovic & rabeder, 1996). early pleistocene lower middle taxa razvo(fe tatinja draga episoricufus thenii thenii retefiomys aflocr;cetus croatieus (bursae)apodemus mystaeinus epime/as epime/as microtus (cf. praehintom) eoratticeps mimomys mafezi mafezi dinaromys da/matinus pliomys (simp/ieor) bo/kayi 4.2. teeth and metapodial bones of the cave bears (ursus spe/aeus rosenm. & heinroth) tn contrast to the uniform incisors, the pre molars and molars (4787 from v indija, 4356 from veli ka pecina and 1682 from vcternica) of a cave bear clearly showed in pre limi nary ana lyscs a great va ri ability in crown morphology, pan icularly the repetition of simi lar or the same c le me nts, 11l0rpholypes tha t appear w it h variab le frequency in deposits of d ifrerent ages. such morphological changes can be traced from simple (primitive) morphotypcs wh ich predominate in oldcr deposits 10 disl inelly complicated (evolved, specialised) morpholypes predominating in younger sediments. this, together w ith differences from premolars w hi ch show characteris tic molarisation processes (rabe­ der, 1983), the molars show the reduction of the pri­ mary elements of the crown fo llowcd by mult iplication of secondary ones (pa unovic, 1988). the ana lyses of odontolog ical ma te r ia l from deposits in the vindija cavc yiclded daw on rapid func­ tional -morpholog ical (microcvolutionary) changes whi­ ch are visible in growth 01" lenght paramcte rs (fig. 4), namcly the ever increas ing percentage of evolved 1110r­ photypes (fig. 5) in the you nger sediment sequences. in the oldest complex (riss, riss/wlirm) there is variation with a high percentage of" more primitive (cleningeroict) c haracte ris tics that probably re presents a transitional form in a phyletic lincage unus denillgeri ur.ms late recent podumci balkan peninsula then;; podumeensis (bursae)epime/as epime/as thenii (div.sp) table 3 geochronolomafezi gieal dispersal of da/matinus bogdanovi endem ic taxa (after bo/kayi paunovic & raseder. 1996). spe/aeus while the typical representative of the spela­ eus-group is characteristic for deposits of wlirmian age (paunovic, 1988). the morphogene tic schemes of premolar-mo lar teeth series of the cave-bear from velika pecina, found in the depositional sequence interpreted as representing the interglacial r iss/worm (malez, 1986), arc char­ acterised by a low percentage of primitive (deni nge­ ro id) morphotypes (fig. 5). these sediments were prob­ ably deposi led duri ng the wilrm (early wo rm), as the rest of the fauna from this sequence does not show any dis tinct c harac teri stics of an int e rglacial peri od (paunov ic, 1988). similar resu lts we re obtained from the material fro m veternica cave w ith a predomince of more evol­ ved morphotypes and d imensions larger than the aver­ age values of the typical urslfs spelaells. considering that the frequency of the appearance or higher evolvcd illorphotypes (fig. 5) corresponds to ihe frequency from younger sequences or vindija cave and also to the morphotype schemes from velika pecina, these results indicate that the oldest deposi ts in veternica cave were laid down during the early w'iinn, bu t not duri ng the interglac ia l riss/wlirm (pa unovic, 1991). this as­ su mption was confirmed by the resuils of the revision of the ungu la te fauna (m iracle & brajkovic, 1992). in accordance with the assumption that microevolu­ tionary c hanges also affec ted the postcranial skeleton, morphome tr ic s tudies have been continued 011 8,267 fig.2 morphotypes or ml belong­ ing to fa,~/li"/i.\· rrom podumci (from malez & rabeder. 1984, p. 477, fig. 28) : 1-4 morpholypc "(i/"{/likae": 5-7 morpholypc ··p(ilil/olljells": 8i 0 rare particutar forms 1\luflovi6 & jambresic: review of the rc..,uits of m orphometric .mj morphogenetic analyses ... 229 ~rnys -.!!.!:lkayi ~----­fljv si5 triangularis simplicior ---hollitzeri chalinei fig. 3 morphotypes of mi belonging to pliolilys from podumci. mor­ photypes in[fexa, li/limlt.i·, fjrugresslo', clw/i/wi defined by sec­ ondary elemen ts (from malez & ra beder, 1984, p. 482, fig. 32). i11ctapodial bones of eave bears [rom vindija cave (fig. 6) . morphogenetic studies showed that changes are the most distinct in th e morphology of th e proximal epi­ physis of (he first metacarpal, namely metatarsal bones and descriptivc stati stics showed that the most chara­ ctcristic length and width parameters of the proximal jo int surface is shorter and wider in older layers, and lon ger and narrower when found in you ngcr levels % 110 105 100 95 7 90 (paunovic et ai. , 1997). morphometric and morpho­ genet ic study of the material from velika pec ina and veternica caves is still in progress . 5. conclusion th is shon review of previously published results of morphometric and morphogenctic studies indicales the need for analyses of the plei stocene vert ebrat es from other locali ties in croatia, with the aim of determining changes in every studied population, species or fauna , and the causes of their occurrcncc and cvolution ary processes. in other words, only the correlation of results of such invcstiga tions fo llowed by geological, sedimcll ­ to logical and other va ri ous analyses shall enab le the es tabli shment of a uniform biostratigraphy of pl eisto­ cene deposits in croatia, and simultaneously solve the dilemma of which quaternary su bdivision to li se 111 practice, especially for the upper pleistocene. acknowledgement we wish to thank ljerka marjanac for her tran­ slation of the text. 6. references bo ulard, c. (1993): biochronologie quantitati ve : concepts, mcthodes e t va liditc.docum. lab. geol. lyon, 128,259 p. carroll, r.l. (1988): vertebrate paleontology ane! evolution.freeman & co, ncw york, 698 p. challne, j. (1972) : les rongcurs pleistocene moyen ct superieur de francc.cahiers de palconl. , c rs, 4 10 p. fig. 4 correlati on or premolar-malar leng ths (%) with mean value s ( 100%) characteris ti c for lypical ur,l'ii.i· .ipela­ ells (after paunov1 c, 1988): i ) veli­ ka peci na; 2) vindi ja j-d: 3) vindija m-l-k: 4) mixnitz; 5) merkenstein : 6) hcrdcngeh6hle: 7) ramesch. 230 p4 200f-__ 150 100 i o mixn 'u 0,-00 hraoem fig. 5 evolutionary scheme of cave bear premolars based on the morphodynamical index: [ = frequency of morphotype (%) x coefficien t of evolution x 100 (after paunovic et al., 1997) . kowalski, k. (1992): remarks on the zoogeography of quaternary rodents in europe.courier forsch. ins!. scnckenbcrg, 153, 197-203. krklec, n. ( 1995): numerical taxonomic classifica­ tion of metapodial bones of urslis spelaeus and u. arclos.nat. croat., 4/4, 227-235, zagreb. malez, m. (1965): peci na vctcmica u medvednici. ­ acta geol. , s, 175-237, zagreb. malez. m. (1986): kvartami sisavci (mam malia) iz vel ike pee ine na ravnoj gori (sr hrvatska, jugoslavija).radovi zavada za znan. rad varazdin, 1,33139, varazdin. malez, m. & rabeder, g. (1984): neues fundma­ terial von kleinsaugern aus der altpleistozanen spaitenfullung podumci i in norddalmatien (kroat­ ien, jugoslawien).beitr. palaont. osten., 11,439510. miracle, p. & brajkovic, d. (1992): revision of the ungulate fauna and upper pleistocene stratigra­ phy of vetemica cave (zagreb, croatia). geol. croatica,45, t 14. paunovic m. (1988): morphometrische und mor­ phogenetische untersuchungen der zahne des ursus spelaells rosenm. & heinroth aus der hohlen nord­ westkroatiens.palaeont. jugosl, 36, 1-40, zagreb. i, 100.000 300.000 • geologia croalica 50/2 • vindija· ef • sal lenhohle 18500 25000 • vindija g 42000 • • vindija ij serze • vindija klm 114000 • scharzfeld • • veaze aze 1-1 m bach 320 00 i, fig. 6 evolutionary scheme of the cave bear mt3 based on the indices: ii = length x 100 i width of diaphysis, 12 = length x 100 / width of distal end (after pa unovic et ai., 1997) . paunovic m. (1991): morphometri sche und mor­ phogenetische untersuchungen der ziihne des ursl/s spelaeus rosenm. & heinroth aus der hohle veter­ nica (nw kroatien). rad hazu, 458/25, 1-18, zagreb. paunovic m., krklec, n. & jambresic, g. (1997): vindija barenhohle in nw croatia.mitt. quartarf. wien, in print. paunovic, m. & rabeder, g. (1996): die alt­ pleistozanen kleinsaugernfaunen razvodje und tat­ inja draga in siid-kroatien.beitr. palaont. osten., 21,69-84. rabeder, g. (1981): die arvicoliden (rodentia, mammalia) aus dem pliozan und clem alleren pleis­ toziin voil niederosterreich.beitr. palaont. osterr. , 8,1 -373 . rabeder, g. (1983): neues von hohlenbaren zur morphogenetik der backenzahne.die hohle, 34/2, 67-85. manuscript received april 14, 1997. revised manuscript accepted november 10, 1997. 07_velic.indd 91 � ab stra ct approximately 104 x 106 m3 of oil (39 fi elds), 6.93 x 106 m3 of condensate (11 fi elds), and 64.92 x 109 m3 of gas (52 fi elds), were recovered in the croatian part of the pannonian basin system during 64 years of exploitation (1941– 2005). the production peak was attained between 1980–1989, when exploitation began in 12 new fi elds. based on their cumulative production, the croatian oil and gas fi elds can be divided into four groups, and the condensate fi elds into three groups. such a division has been supported by analysis of recovery, number of reservoirs, porosity and permeability, age and lithology of reservoir rocks. the longest production period is assumed for the fi rst group of fi elds; for oil it is approximately 55 years, for condensate 46 and gas 36 years. in the favourable fi rst group the average number of reservoirs is 16 for oil and 11 for gas. lithological composition is highly favourable, because reservoirs are represented mostly by sandstones of pannonian and pontian age with high porosities and permeabilities. a relatively homogeneous sandstone lithology, including good regional seals like marls, enables an increase in recovery through the use of secondary and tertiary recovery methods. also, water-fl ooding will remain the dominant secondary-recovery method for increased production in the future. keywords: statistics, pannonian basin system, hydrocarbon fi elds, croatia, neogene and pre-neogene reservoirs, recovery, exploitation period reservoir geology, hydrocarbon reserves and production in the croatian part of the pannonian basin system � josipa velić1, tomislav malvić1,2, marko cvetković1 and boris vrbanac3 1 department of geology and geological engineering, university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, 10000 zagreb, croatia; (josipa.velic@rgn.hr; marko.cvetkovic@rgn.hr) 2 sector for geology and reservoir management, ina industry of oil plc., exploration and production of oil and gas, šubićeva 29, 10000 zagreb, croatia; (tomislav.malvic@ina.hr) 3 exploration and production of oil and gas, sector for oil and gas production in se europe (retired), ina industry of oil plc., šubićeva 29, 10000 zagreb, croatia; (boris.vrbanac@gmail.com) doi: 104154/gc.2012.07 geologia croatica 65/1 91–101 5 figs. 4 tabs. zagreb 2012 geologia croaticageologia croatica 1. introduction this work presents a detailed overview of croatia’s oil, gas and condensate reserves. the data is derived from oil and gas fi elds located in the croatian part (cpbs) of the pannonian basin system (pbs), and to cover the whole country’s reserves, the adriatic gas fi elds were also added. however, as the main topic is the cpbs, the most well know data on the evolution of the entire pannonian basin system are presented by way of an introduction, followed by further review of the croatian part. these data are crucial to understand the location, age and recovery factors from all types of reservoirs as well as assumptions about future production. the pannonian basin system (pbs) is a back arc basin system that belongs to an area in the past covered by the central paratethys, and younger brackish and fresh-water environments formed from paratethys. pbs generation started with convergence and subduction of the apulian plate under the dinarides during the styrian orogenic phase, developing the southern (periadriatic-vardar lineament) and northern (outer carpathian) boundaries. however, the southwestern boundary of the central paratethys area located further to the south from the periadriatic-vardar lineament was represented by an array of small, fresh-water neogene basins within the dinarides that were never invaded during geologia croatica 65/1geologia croatica 92 their evolution by marine transgressions in paratethys pavelić (2002). these basins have never been considered as parts of the mediterranean or central paratethys, although sediments and fauna can be correlated with some pbs characteristics. inside pbs, numerous basins, depressions and subdepressions were formed along dextral and sinistral strike-slip faults (fig. 1a, modifi ed after royden, 1988). the terms “basin, depression or subdepression” described areal geometry of opened areas. the very fi rst extensions were initiated in the ottnangian (royden, 1988; rögl, 1996, 1998), but sediments of this age were only deposited and preserved locally. the extensional period continued through the karpathian when restricted lacustrine and fl uvial sediments were deposited in the apuseni mts., carpathians and podolian upland as well as on the margin of the alps and the bohemian massive (e.g., rögl 1996, 1998). during the badenian, mostly marine sedimentation and maximum extensional displacements are characteristic for the entire pbs (e.g., rögl, 1996, 1998), including the cpbs (e.g., vrbanac, 1996). the real marine environment with “normal” salinity was dependent on the existence of connections with large “oceanic” areas, i.e. with the mediterranean in the south-west and the indo-pacifi c to the southeast through trans-tethyan trench corridors. the lower badenian transgression covered the entire basin, from austria to romania (transylvania) and from the carpathians to the dinarides. the carpathians and the apuseni mts., remained perhaps the two most prominent areas with island arcs. however, in the middle badenian, the marine environment of normal salinity was limited to the western part of central paratethys (i.e. parts of poland, hungary, slovenia and croatia). elsewhere, sediments of a regional regression phase and evaporites have been proven. deposition of thick evaporate sediments signal the middle badenian salinity crisis in the transcarpathian basin, transylvanian basin and carpathian foredeep (kovač et al., 2004, 2007). the last regional fl ood in the pbs occurred during the late badenian, when the connections with the mediterranean and indo-pacifi c were interrupted (e.g., steininger et al., 1978). some areas on the margins of the pbs are characterised in the upper badenian by evaporites, including the carpathian foredeep (e.g., peryt, 1997, 1999; mǎrunteanu, 1999; andreyeva-grigorovich et al., 1997) and the transylvanian basin (e.g., chira, 2000). in the cpbs, pavelić (2001) described the period of the late badenian as the transition between the extensional and post-extensional stages. similarly, vrbanac (1996) considered that northern croatia remained a marine environment at that time, where the present-day mountains represented islands or remarkable submarine highs. consequently, the next sarmatian age is the period when a continuous marine environment began to be progressively reduced (e.g., rögl, 1996, 1998), resulting in isolated areas that eventually became brackish and fresh water lakes during the late miocene. psammitic, and pelitic, clastic sedimentation in littoral environments, was sporadically interrupted by deposition of large quantities of coarse-grained carbonate material, originating from eroded, near-shore reefs. royden (1988) noted a major phase of extension figure 1: croatian geotectonical units in pannonian basin system (range of depressions) and hydrocarbon fi elds (modifi ed after royden, 1988; velić 2007; malvić & velić, 2010; 2011). fields named at fi gure are mentioned in the text. velić et al.: reservoir geology, hydrocarbon reserves and production in the croatian part of the pannonian basin system geologia croatica 93 that fi nished over most of the pannonian basin system in the early pannonian. in the post-extensional phase, the generator of dynamism was thermal subsidence, triggered by cooling of the lithosphere. subsidence was stronger in the central part of the basin system (approx. 2 km in 10 ma), and alkali volcanic activity occurred locally. from the early pannonian, continuing into the pontian, sedimentation took place in brackish and fresh water lacustrine environments (e.g., rögl, 1996, 1998). sediments were transported through delta and prodelta systems, or by turbiditic mechanisms capable of moving detritus dozen of kilometres. turbidites, as the main transport mechanism in the cpbs, were periodically activated in response to gravitational and/or tectonic instability on the structural “ramps” (e.g. malvić & velić, 2011). the eastern alps were the main clastic sediment source for the croatian depressions in the late miocene. eventually, the late pontian, and especially the pliocene and quaternary were characterised by fl uvial, lacustrine and marshy sedimentation along with aeolian sediments in the youngest parts of the quaternary. these periods completed the basin infi ll and resulted in formation of the present-day relief. the tectonic regime was compressional, indicated by reverse faults and overthrusts (royden, 1988), and often along reactivated older fault planes with inversion of displacement as proven by the numerous relative young hydrocarbon traps. also in the cpbs, tectonic and depositional properties were similar (e.g., velić, 2007). interestingly, extensional and compressional phases in the pbs during the neogene and quaternary, and recently in the cps, can be divided into two transtensional (badenian and pannonianearly pontian) and two transpressional (sarmatian and late pontian-quaternary) phases (in malvić & velić, 2011). 2. geological settings and hydrocarbon properties in the cpbs the area of the cpbs is divided into the drava, sava, mura, and slavonija–srijem depressions (fig. 1b). although each of these has their local characteristics, the general evolution of their depositional environments, transport mechanisms, tectonics and dominant lithologies is very similar, and can be described as a unique area of the pbs. the boundaries between the depressions are mountains and massifs in northern croatia, or their subsurface extensions, which can be recognised as uplifted structures or buried hills covered by neogene and quaternary sediments (velić et al. 2002; velić 2007). they are recognizable in present-day relief or in the subsurface via well or seismic data. 2.1. depositional megacycles of neogene and quaternary systems in the cpbs neogene and quaternary sedimentary systems are subdivided into three megacycles (velić et al., 2002). neogene and older outcrops in the cpbs are rare as most of the surface is covered by holocene sediments (velić, 2007). at the margins of the depression, the thickness of neogene sediments varies between 500–1500 m, rising towards the centres, to 3500 m thick in slavonia–srijem, 5500 m in the sava and mura and almost 7000 m in drava depressions respectively (fig. 1b; velić et al., 2002; saftić et al., 2003). the isochore 0 m is proven along the highest mountains in northern croatia. these central basin zones of maximum deposit thickness are locations of thick intervals of cyclic, i.e. rhythmic deposition (filjak et al., 1969; šimon, 1980). velić et al. (2002) described three sedimentation megacycles in the neogene and quaternary. these cycles consist of sequences of well defi ned lithostratigraphic formations. each megacycle includes sediments deposited during cycles of relative sea level change. in the 1st part of the cycle the water level is gradually rising, and in the 2nd it is suddenly dropping (e.g., mitchum 1977). generally, each megacycle is composed of a regular/ordered superposition of well defi ned lithologic units (formations and/or members). a particular cycle is measured in tens or hundreds of metres (e.g., mathur, 1981), but an entire megacycle in the cpbs can reach more than 1000 m (velić et al., 2002; velić, 2007). the oldest, or 1st megacycle (fig. 2), comprises middle miocene sediments, i.e. the prečec formation (fm.) in the sava depression, moslavačka gora fm. in the west drava depression, the vukovar fm. in the east drava and slavonia–srijem depressions and the murska sobota fm. (except the formation top) in the mura depression. lithologically it is a very heterogeneous sequence. it comprises coarse grained clastics (breccia, conglomerates and sandstones), fi ne grained clastics (clays, marls and calcareous, sandy, argillaceous marls) and carbonates (limestones and calcareous sandstones). according to ćorić et al. (2009) an initial marine transgression occurred later in the croatian part of the pannonian basin – 1 ma after the beginning of the badenian. this was dated using nannofossil marker species, especially figure 2: chronostratigraphic units with l ithostratigraphic units in the rank of formations valid for the croatian part of the pannonian basin system (velić et al., 2002). geologia croatica 65/1geologia croatica 94 the nannoplankton nn5 zone, resulting in sediments previously regarded as karpathian now being of badenian age. all sediments that belonging to 1st megacycle but have lower miocene age, also are of very restricted areal extension and it is why they are excluded from this study. the 2nd megacycle (fig. 2), is of late miocene age (belonging to the pannonian and pontian stages). it comprises sediments of the sava group (ivanić-grad, kloštar ivanić and široko polje formations) in the sava depression. in the western drava depression, the bilogora formation (late pontian) is equivalent to the široko polje formation. in the east drava and slavonia–srijem depressions, equivalent formations are the vinkovci and vera formations. finally, in the mura depression, this megacycle comprises the lendava formation and the lower part of the mura formation. the 3rd megacycle (fig. 2), is of pliocene, pleistocene and holocene age. according to the lithostratigraphic nomenclature it comprises the lonja formation in the sava and the west drava depressions, the vuka formation in the east drava and slavonia–srijem depressions and the mura formation in the mura depression. 2.2. hydrocarbon reserves in the cpbs analysis of the number of discovered and active fi elds (39 oil, 11 condensate and 52 gas fi elds) between 1941–2005 (fig. 3) showed that the number of new fi elds rapidly increased in the sixties for oil, and in the eighties for gas. this period was followed by a drastic decline in new discoveries. generally, the 30 years between1959–1989 can be described as a highly successful exploration period, when potential structural and combined traps could be discovered with the use of several easily applied methods such as gravimetric and seismic surveys. these were often discovered by the very fi rst exploration well. improved seismic survey methods, focused on depths greater than 2000 m, played a critical role in the discovery of the largest croatian gas-condensate reservoirs in the drava depression in the eighties. reservoirs are described as oil, condensate and gas pools. 2.3. main reservoir lithofacies in the cpbs the oldest fi elds are the gojlo, šumečani, bunjani, kloštar and dugo selo fi elds, (production began between 1941 and 1957). the youngest fi elds are ðeletovci and privlaka (1984), bizovac and leticani (1989) and galovac–pavljani (1991). the group of “the oldest fi elds” is located in the sava depression (fig. 1b) and includes three different reservoir lithofacies: two of them are neogene sandstone and coarsegrained clastics while the third is in the palaeozoic magmatic and metamorphic rocks of the crystalline basement. almost all of these fi elds are of the “buried hill” type trap (šumećani, bunjani, kloštar, ðeletovci, privlaka, galovac–pavljani), where signifi cant quantities of oil and gas are accumulated across an erosional unconformity between the crystalline basement and the coarse-grained badenian sediments. quantitative data and conclusions from previous studies (bassiouni & velić, 1996; belošić, 2003; dragaš et al., 1995; hernitz et al., 2002; malvić & velić 2010; malvić et al., 2005; jüttner et al., 2001; saftić et al., 2001; velić et al., 2002) contribute to estimation of the exploration level of hydrocarbon bearing rocks in the croatian part of the pannonian basin system. these rocks were classifi ed into two complexes with regard to their composition: (1) the rocks of palaeozoic and mesozoic ages represented by magmatic, metamorphic and carbonate rocks and (2) the clastics of neogene and quaternary ages. observing the volume of neogene and quaternary sediments explored by drilling, there is good potential for successful exploration of the remaining hydrocarbons, especially in areas among the discovered fi elds (vrbanac et al., 2010). younger sediments (upper part of the upper miocene, pliocene, pleistocene and holocene) have not been explored at all, although the presence of gas (especially biogenic methane) has been identifi ed in several fi elds and prospects. the oldest neogene rocks, older than lower pannonian, probably contain signifi cant undiscovered hydrocarbon reserves of oil and thermogenic gas, because these deposits constitute the principal sequences of neogene source rocks (especially in the badenian, i.e., the middle miocene, trofigure 3: number of discovered oil (left) and gas (right) fi elds during the particular time periods. velić et al.: reservoir geology, hydrocarbon reserves and production in the croatian part of the pannonian basin system geologia croatica 95 skot-čorbić et al., 2009; saftić et al., 2003; velić et al., 2000; zečević et al., 2010). the potential of these deposits as unconventional reservoir rocks remains to be explored. 2.4. remaining recoverable and probable reserves in the cpbs a regional study was recently published concerning exploration and production (e&p) ventures in eastern and central europe, which also gave the potential of remaining recoverable hydrocarbon liquids in this area (dobrova et al., 2003). this study reports that “e&p activities were particularly successful, in terms of having discovered economically viable oil and gas reserves and having achieved incremental production, in poland, lithuania, hungary, the czech republic and romania”. of course, new discoveries of hydrocarbons are small to moderate, but it is expected that they will greatly contribute to the reserves’ replacement in these countries. cited paper reveals that croatia’s resources are 6% of the total recoverable resources in central and eastern europe, which places croatia in third place along with austria and belarus, after romania and ukraine. dobrova et al. (2003) stated two conclusions of particular interest: (a) improved drilling success ratios were achieved mainly by state companies, since they preferred to drill appraisal and/ or low risk prospects while largely reduced drilling frontier wells; and (b) current production growth will come mainly from traditional producers’ activities, not from those of newcomers. this means that the decline of oil and gas production/proven reserves in croatia may be slowed or could cease with the addition of the production from satellite reservoirs of existing fi elds rather than from new discoveries. malvić & rusan (2009) calculated the minimum size of a commercial discovery of oil in the croatian part of the pannonian basin system as being of 2 x 105 m3 of recoverable oil. such discoveries can be expected even in marginal areas (like the bjelovar subdepression) of the drava or sava depression that are the largest depressions in croatia. they calculated, that to discover one new fi eld with an expected profi t of more than 2 x 106 usd (net present value, 13.52 x 106 usd, and risk adjusted value of discovery 35%), approximately 50 x 106 usd should be invested in exploration of the geological area where such discoveries are assumed. malvić & rusan (2009) also pointed out that more prospective plays for new fi elds would be in rocks of lower and middle miocene age, or in the mesozoic or palaeozoic basement. it should be mentioned that between the miocene and the mesozoic-palaeozoic rocks is a great tectonic and erosional unconformity, across which large secondary pore volumes in basement rocks are developed, as a result of a long period of weathering, dissolution and fracturing. in any case, there is strong evidence that the croatian part of the pannonian basin system contains signifi cant unproven (probable & possible) hydrocarbon reserves, in existing reservoirs. it is especially valid in clastic reservoirs (breccia or sandstone). better use of secondary or tertiary recovery methods might make it possible to recover part of these trapped or bypassed reserves as well as supporting the extended production from presently proven reserves in certain reservoirs. 3. basic reservoir characteristics in croatia, about 3610 wells were drilled prior to 2002. all fi elds are grouped by their cumulative production, into large, medium, small and very small fi elds, and those currently not productive (tables 1–4). for oil and gas, this grouping is as follows: (a) large fi elds, which produced more than 106 m3 of oil/ condensate or more than 109 m3 of gas; (b) medium fi elds, which produced 105–106 m3 of oil/condensate or 108–109 m3 of gas; (c) small fi elds, which produced 104–105 m3 of oil, <105 condensate or 107–108 m3 of gas; (d) very small fi elds, which produced less than 104 m3 of oil or less than 107 m3 of gas. as expected, the large fi elds (group 1) accounted for 93.07% of total oil production up to 2005, from group 2 another 6.67%, and from groups 3 and 4 the amount of production was negligible. for condensate, the reservoirs of group 1 accounted for 82.13%, and from gas reservoirs group 1 recovery was 90.75% of total production. the life-cycle of commercial production is generally long; e.g., the average production period for such fi elds is estimated at 55 years. such fi elds characterised by an extremely long production period include the mramor brdo (80 years), okoli (74 years) and stružec (72 years). tables 3 and 4 may indicate why fi elds from group 1 are more productive than others, suggesting the relevance of a higher number of reservoirs, deeper traps, higher porosity and permeability etc. data from tables 1 (oil), and 2 (gas and condensate) supported the classifi cation of fi elds in groups by analysis of petrophysical and statistical data as well as other geological information including depression, age, lithology and trap. 3.1. reservoir properties of oil reservoirs data are taken from 39 oil fi elds, 52 gas fi elds and from 8 fi elds that were never productive. data for condensate reservoirs are from 11 active fi elds and 1 recently discovered fi eld. some earlier statistical analysis for data mostly from sandstone reservoirs of lower pontian age, were also included in this summary (malvić et al., 2005; saftić et al., 2001). for oil fi elds, group 1 reservoirs are sandstones of pannonian and pontian age, except for the beničanci field, where the reservoir is a badenian breccia. groups 2, 3 and 4 include reservoirs of heterogeneous lithology and ages: deposits in the drava depression consist of effusives, sandstones, breccias and conglomerates of (possible karpathian) and badenian ages. other reservoirs include carbonates of triassic, cretaceous and oligocene(?)-miocene ages. in the slavonia–srijem depression, reservoir rocks are represented geologia croatica 65/1geologia croatica 96 by palaeozoic granite, gneiss, schist and diabase as well as conglomerates, breccias and sandstones of badenian age. the oil reservoirs (table 1) of group 1 are also characterised by high porosity, permeability, oil saturation and recovery factor (malvić et al., 2005; saftić et al., 2001; velić et al., 2002; velić 2007). interval porosity is greatest for group 1, with 19.9–22.4%, followed by 16.27–18.49% for group 3, 14.29–18.32% for group 4, and 12.01–16.33% for group 2. the reservoir permeability is signifi cantly reduced in the smaller size reservoirs: it is 15.38–262.51 x 10–15 m2 (median value; 2–139 x 10–15 m2) in group 1 reservoirs, 6.01–174.50 x 10–15 m2 (median 0.83–28.30 x 10–15 m2) in group 2, 6.97– 21.65 x 10–15 m2 (median; 4.00–18.30 x 10–15 m2) in group 3 and 14.17–25.17 x 10–15 m2 (median; 6.00–26.60 x 10–15 m2) in the smallest group 4 reservoirs. median values are more valid than average ones, be cause the permeability input data set is characterised by many extreme values. a decline in maximum permeability is clearly observable. consequently, recovery factors also decline from 36.47% to 24.39%, 11.33% and 8.53%, respectively. 3.2. reservoir properties of gas and condensate reservoirs the gas and condensate fi elds are also classifi ed in four and three groups respectively (table 2), regarding the statistics of geological, and petrophysical data. the four groups of gas fi elds (table 2), are based on the recovered volumes of gas. reservoirs are in palaeozoic and mesozoic rocks in 10 fi elds, middle miocene rocks in 22 fi elds and in the upper miocene rocks in 20 fi elds. however, there is no regularity of reservoir ages in the four groups. predicted periods of production vary between 10 and 31 years. not counting the gas fi elds in the adriatic sea, the production periods would be between 5 and 23 years. the largest fi elds could have the longest production, similar to oil fi elds. other parameters listed for gas fi elds are characterised by similar trends observed for oil fi elds. the condensate is added to gas fi eld’s data which mostly have the same characteristics. the main differences are in the deeper subsea depth of condensate reservoirs and number of analysed reservoirs (table 2). 4. size of fields, reserves and production until 2005 the quantities of recoverable and recovered hydrocarbons in the period 1940–2005 are shown in fig.3. the cause for a rapid production decline after 1989 is threefold: depletion of older fi elds, serbian occupation of eastern slavonia in 1991–1995 and consequently a substantial decrease in exploration activity, resulting in no addition of reserves during this period. the maximum annual oil production was more than 3.1 x 106 tons (1979–1982 and 1985–1988). gas production reached a maximum during the periods 1987–1990 (more than 2 x 109 m3) and 1993 (2.05 x 109 m3). the total original hydrocarbon in place (ohip, sometimes also called petroleum initially in place), is about 740 x 106 m3 of equivtable 1: oil fi elds and reservoir groups, geological, statistical and petrophysical data. oilfields variables 1st group large fields 2nd group medium fields 3rd group small fields 4th group very small f. geological data depression(s) sava, drava, slavonia-srijem sava, drava, slavonia-srijem sava, drava, mura drava age (mostly) pannonian and pontian middle miocene, mesozoic, palaeoz. (mostly) middle miocene upper miocene, pliocene reservoir lithology (mostly) sandstones and breccia coarse-grained, carbonates, metamorphic breccia, sandstones sandstones trap type structural, struct.-stratigraphic structural, struct.-stratigraphic struct.-stratigraphic structural, struct.-stratigraphic statistical data number of fi elds 8 11 18 3 absolute depths to res. top (m) –570 to –1700 –310 to –2280 –790 to –2350 –570 to –1960 average no. of reservoirs 13 5 5 2 share in total production (%) 93.067 6.67 0.26 0.003 prognosis of product. (years) 55 46 36 10 petrophysical data porosity (%) 16.90–22.39 12.01–16.33 16.27–18.48 14.29–18.32 permeability (10–15 m2) 3.73–384.00 8.16–196.60 2.9–92.3 25.17–832.96 aver. oil density (kg/m3) 847.6 873.6 857.96 832.96 velić et al.: reservoir geology, hydrocarbon reserves and production in the croatian part of the pannonian basin system geologia croatica 97 alent oil (oil, condensate, gas), with recoverable reserves of 112 x 106 m3 of oil, 9.5 x 106 m3 of condensate and 93.1 x 109 m3 of gas (fig. 4) respectively. up to 2005 a total of 179 x 106 m3 of equivalent oil was recovered 104 x 106 m3 oil from 39 fi elds, 6.93 x 106 m3 condensate from 11 fi elds and 64.92 x 109 m3 gas from 52 fi elds (velić et al., 2008). by 2005, 37 fi elds are still producing. table 2: gas fi elds and reservoir groups, geological, statistical and petrophysical data, condensates are listed separately in italics or with additional marks* in geological data. gasfields variables 1st group large fields 2nd group medium fields 3rd group small fields 4th group very small f. geological data depression(s) drava* sava, northern adriatic drava*, sava* drava*, sava, slavonia–srijem, mura* drava*, sava mura age palaeozoic*, mesozoic*, miocene*, pliocene, quaternary mesozoic*, miocene* pliocene palaeozoic, mesozoic, miocene*, pliocene palaeozoic, miocene, pliocene reservoir lithology magmatic*, metamorphic*, carbonate*, breccias*, sandstone carbonate*, breccias*, sandstone* carbonate, breccia, sandstone* magmatic, breccia, sandstone trap type structural*, struct.-stratigraphic structural*, struct.-stratigraphic structural*, struct.-stratigraphic*, stratigraphic structural, struct.-stratigraphic statistical data number of fi elds 13 (+2) 16 (+3) 18 (+6) 5 absolute depths to res. top (m) –150 to –3054 –2950 to –3050 –240 to –3400 –1450 to –3400 –240 to –2230 –710 to –1920 –350 to –2110 aver. no. of reservoirs 13 1 6 6 5 8 5 share in total production (%) 90.75 82.13 7.83 17.63 1.38 0.24 0.04 prognosis of product. (years) 31 37.5 26 34 10 26 n/a petrophysical data porosity (%) 16.60–25.23 (11.17–16.97) 16.39–21.96 (16.52–21.28) 14.31–18.21 (3.50) 12.28–15.64 permeability (10–15 m2) 5.87–184.69 (2.07–32.10) 4.96–30.51 (14.77–20.79) 30.20–151.82 (0.08–20.70) 2.85–13.25 relative aver. gas density (air=1) 0.672 (784.0 kg/m3) 0.705 (720.0 kg/m3) 0.678 (723.9 kg/m3) n/a figure 4: relationships between recoverable and recovered reserves of oil (left) and gas (right) during the particular time periods. geologia croatica 65/1geologia croatica 98 table 3 gives data on production and recoveries obtained for oil, divided into groups of large, medium, small and very small fi elds. table 4 gives data for production and recoveries of gas, divided into groups of large, medium and small fi elds as well as fi elds that are still not in production. in the 1970’s, when oil production peaked, recoveries by primary methods were as follows: 16– 20% (dissolved gas drive) 20–25% (gas cap drive) 30–50% (water drive). the average recovery was 25%. considering the largest fi elds with sandstone reservoirs, the following recovery was achieved: 16% in the ivanić and žutica fields, 31% in the kloštar field and 39% in the stružec field. a maximum of 51% has been recovered from breccia in the beničanci field. the average total recoveries obtained until 2005 differ for fi eld sizes and fl uids. generally recoveries are higher from the larger reservoirs. fields were selected in four groups for oil and gas/condensate as in tables 3 and 4, based on production to 2005. three mechanisms are in use for oil production: artifi cial lift (in a narrow sense, meaning a mechanical device inside the well, i.e., hydraulic pumping for transmitting energy to the bottom of the well); gas lift (a widely used artifi cial sub-method), including injection of gas in the tubing to reduce the weight of the hydrostatic column; table 3: oil reserves and production (up to 2005). oil (in m3) geological reserves recoverable reserves recovered reserves remaining reserves total recovery (%) reached rec. (%) large fi elds (recovered >1,000,000 m3) 269,540,224 103,216,280 96,832,281 6,383,999 36.47 33.55 medium fi elds (100,000–1,000,000 m3) 39,931,399 8,290,547 6,943,553 1,346,994 24.92 21.40 small fi elds (10,000–100,000 m3) 5,032,466 463,961 266,669 197,292 8.51 6.21 very small fi elds (<10,000 m3) 1,088,161 88,871 3,916 84,955 8.03 0.42 table 4: gas reserves and production (up to 2005); condensates are listed separated in italic with marks* gas (in m3) geological reserves recoverable reserves recovered reserves remaining reserves total recov. (%) reached rec. (%) large fi elds (recovered >1,000,000,000 m3) 116,356,798,000 83,292,609,000 58,913,729,060 24,378,879,940 69.72 55.11 *large condensate fi elds (>1,000,000 m3) 13,125,352 8,940,100 5,693,324 3,246,776 78.88 48.05 medium fi elds (100,000,000 – 1,000,000,000 m3) 7,933,806,000 7,702,918,960 5,083,771,659 2,619,147,301 62.05 53.28 *medium condensate fi elds (100,000 – 1,000,000 m3) 3,450,332 1,763,313 1,222,079 541,234 51.10 35.42 small fi elds (10,000,000 – 100,000,000 m3) 6,021,423,000 3,229,932,755 896,153,610 2,333,779,145 47.27 37.06 *small condensate fi elds (<100,000 m3) 40,592 20,475 16,662 3,813 50.18 48.58 very small fi elds (<10,000,000 m3) 277,400,000 43,890,000 21,848,218 22,041,782 23.83 14.36 never in production (gas and condensate) 12,203,694,000 6,417,110,000 0 6,417,110,000 51.92 0 19,251 11,551 0 11,551 60 0 velić et al.: reservoir geology, hydrocarbon reserves and production in the croatian part of the pannonian basin system geologia croatica 99 natural fl ow production, when oil-reservoir pressure is suffi cient to transmit the hydrocarbons to the surface. production mechanisms used in croatian fi elds were analysed with respect to fi eld sizes. the most often used mechanisms were: • for the largest fi elds, artifi cial lift and gas lift; for four fi elds, natural fl ow; • for medium fi elds, artifi cial lift; • for small fi elds, artifi cial and gas lifts; • for very small fi elds, artifi cial lift and natural fl ow. the most frequently applied secondary recovery method for many croatian fi elds is water injection. approximately half of the present croatian production comes from waterfl ooded reservoirs (e.g. žutica, ivanić, beničanci etc.). recovery from these reservoirs can reach 40%, thanks to a favourable oil/water viscosity ratio. in porous reservoirs, however, tertiary recovery methods, also called unconventional, enhanced or improved oil recovery (abbr. eor or ior) are successfully applied, as calculated for parts of the ivanić and žutica fields (e.g. sečen et al., 2002). during the last 20 years, the application of co2 injection was tested for 14 croatian fi elds in the ina laboratories (goričnik & domitrović, 2003). this method was found to be applicable in 33% of reservoirs attaining a complete fl uid miscibility, in 59% of reservoirs reaching a partial miscibility and in 8% of reservoirs with no fl uid miscibility. the amount of total bypassed oil in the water-fl ooded reservoirs of the 14 fi elds mentioned is about 140 x 106 m3, which means that appropriate tertiary methods could yield another 9–24 x 106 m3 of liquid hydrocarbons. gas injection (as gas lift) resulted in an approximate additional 14.5 x 106 m3 oil recovered until the end of 1987. 5. discussion the data presented are a valid source for estimating the hydrocarbon potential of the croatian part of the pannonian basin system. listed are in-place and recoverable quantities as well as cumulative hydrocarbon production data until 2005. they are related to geological, petrophysical and statistical data about all types of reservoir lithologies in the analysed area. such a list should be useful when determining how to increase recovery from different types of lithologies, and how to select the most appropriate secondary and tertiary methods of recovery in the analysed lithologies. the results obtained can be viewed in context with earlier published results (dobrova et al., 2003) in which the authors provided a valuable review of hydrocarbon reserves and potential over a large region of central and eastern europe. according to available data, they reported comprehensive exploration and production results in romania, hungary, czech republic, poland and lithuania, covering recent successful ventures. these authors ranked croatia in third place according to the remaining recoverable resources in central and eastern europe at the end of 2002 (romania fi rst, 39%; ukraine second, 25%; and croatia, austria and belarus third, 6% etc.). this is why we re-assessed our recoverable resources, cumulative production and reserves given in table 2 of the previous report (dobrova et al., 2003), using 42-gallon-barrel units. the conversion of units has been accomplished using a 6.2898 barrel (usa) for 1 m3 of oil. more recent production data from croatian hydrocarbon regions are lower, compared with data published in 2003. even if condensate reserves are added to oil (i.e. liquid) reserves, new values of oil are still lower (122.79 vs. 141.18 x 106 m3), and consequently reserves in proven traps are 62.5% lower than previously published. it is also clear that remaining gas reserves are lower, at 56.6%. it is certain that new results, taken from data to 2005, are not overestimated, assuming that larger volumes can be expected only in new prospects, fi elds or satellite reservoirs. 6. conclusions for future exploration and the stratigraphic target some of the remaining hydrocarbons could still be recovered from the reservoirs/fi elds with a long production record in the croatian part of the pannonian basin system (fig. 5). figure 5: status of the croatian recoverable hydrocarbon reserves. geologia croatica 65/1geologia croatica 100 also there are some less spectacular (“subtle”) but potentially large reservoirs; this is also supported by recovery rates given in tables 3 and 4. such potential petroleum resources could add to proven reserves, especially in the drava and sava depressions. “subtle” reservoirs can be recognized using improved geological models of entire petroleum systems. signifi cant reservoir volumes can be expected in: • neogene basement rocks, along depression margins and/or uplifted palaeorelief (buried hills). • middle miocene sediments, consisting of different lithofacies. these formations could be favourable for discovery of stratigraphic traps along the fl anks of buried hills or at abrupt facies changes in palaeo-depositional plains. • typical heritage structures (or anticlines) above preneogene buried hills. pannonian and pontian sediments in which the main focus should be stratigraphic traps, typically along subtle or gentle anticlinal structures. such potential traps can be observed on structural maps and especially on 3d seismic arrays by attribute analysis, searching for gradual transitions between channel sandstones and marls deposited in basinal plains. those sediments have the most favourable petrophysical properties. differential compaction, which can be a signifi cant mechanism of folding, especially in areas where depths are quite different over small lateral distances, causing “false” or “compaction” anticlines. sediments of all ages, for which further research needs to be undertaken for identifi cation of possible traps along main basinal faults that infl uenced sedimentation. these faults had the main role in basin subsidence, but many faults also are proven migration pathways for hydrocarbons from source rocks to reservoir rocks. special attention should be paid to transform zones and related structural traps. it is obvious that there is a need for renewing and/or intensifying geological and geophysical exploration and subsequent drilling in the croatian part of the pannonian basin system. we believe this can be done in carefully selected areas, leading to successful prospects and plays. acknowledgment this work represents part of a multidisciplinary geological investigation that was performed in 2009 and 2010 within the project entitled ‘stratigraphical and geomathematical researches of petroleum geological systems in croatia’ (project no. 195-1951293-0237), which was fi nanced by the ministry of science, education and sports of the republic of croatia. references andreyeva-grigorovich, a.s., kulchytsky, y.o., gru zman, a.d., lozynyak, p.y., petrashkevich, m. i., portnyagina, l.o., ivanina, a. v., smirnov, s.e., trofimovich, n.a., savitskaya, n.a. & shvareva, n.j. (1997): regional stratigraphic scheme of neogene formations of the central paratethys in the ukraine.– geol. carpath., 48/2, 123–136. bassiouni, z.k. & velić, j. (1996): prospecting for bypassed oil and gas.– in: velić, j., hernitz, z. & saftić, b. (eds.): 1st international symposium of petroleum geology “economic aspects of petroleum exploration. an approach to rational exploration“, zagreb, proceedings, 197–202. belošić, ž. (2003): istraživanje i proizvodnja nafte i plina [exploration and production of oil and gas – in croatian].– 2nd international scientifi c-professional congress on petroleum industry, ina-naftaplin, zadar, 30.9.–3.10. 2003., proceedings, 27–38. chira, c. (2000): nannoplancton calcaros si moluste miocene din transilvania [miocene calcareous nannoplankton and molluscs from transylvania].– ed. carpatica, 183 p., 21 fi gs., 8 tab., 20 pl., cluj–napoca. ćorić, s., pavelić, d., rögl, f., mandic, o., vrbac, s., avanić, r., jerković, l. & vranjković, a. (2009): revised middle miocene datum for initial marine fl ooding of north croatian basins (pannonian basin system, central parathetys).– geol. croat., 62/1, 31–43. dobrova, h., kolly, e. & schmitz, u. (2003): e&p ventures in the eastern-central europe transformation states after 1989 – a re view of expectations and results.– oil gas eur. mag., 4, 172–182. dragaš, m., prelogović, e., jamičić, d., ivković, ž., velić, j. & saftić, b. (1995): hydrocarbon distribution as the result of tectonic events in the croatian part of the pannonian basin.– eaeg & eapg, 57th conference and technical exhibition, glasgow, extended abstracts, 2, 570–571. filjak, r., pletikapić, ž., nikolić, d. & aksin, v. (1969): geology of petroleum and natural gas from the neogene complex and its basement in the southern part of the pannonian basin, yugoslavia.– aapg, conference of institute of petroleum and aapg, brighton, proceedings, 113–130. goričnik, b. & domitrović, d. (2003): laboratory analyses of co2 process applicability in oil fi elds of republic of croatia.– naftaplin, 1, 5–12. hernitz, z., vrbanac, b., pavlović, z. & bokor, n. (2002): on the exploration level of the croatian part of the pannonian basin.– nafta, 53/10, 363–370. jüttner, i., saftić, b. & velić, j. (2001): distribution of porosity and permeability within the pontian sandstones in the western part of sava depression in relation to their stratigraphic architecture and palaeotectonic relations.– nafta, special issue, 1, 139–144. kovač, m., andreyeva-grigorovich, a., bajraktarević, z., brzobohaty, r., filipescu, s., fodor, l., har zhauser, m., oszczypko, n., pavelić, d., rögl, f., saftić, b., sliva, l., kvaček, z., hudáčkova, n. & slamková, m. (2004): paleogeography of the central paratethys during the karpatian and badenian. scripta fac. sci. nat. univ. masaryk. brunensis, vol. 31–32 (2001–2002), geology, brno, 7–17. kovač, m., andreyeva-grigorovich, a., bajraktarević, z., brzobohaty, r., filipescu, s., fodor, l., harzhauser, m., nagymarosy, a., oszczypko, n., pavelić, d., rögl, f., saftić, b., sliva, l., studencka, b. (2007): bade nian evolution of the central paratethys sea: paleogeography, cli mate and eustatic sea-level changes.– geol. carpath., 59/6, 579–606. malvić, t. & rusan, i. (2009): investment risk assessment of potential hydrocarbon discoveries in a mature basin.– oil gas eur. mag., 2, 67–72. malvić, t. & velić, j. (2010): relation between effective thickness, gas production and porosity in heterogeneous reservoirs: an exvelić et al.: reservoir geology, hydrocarbon reserves and production in the croatian part of the pannonian basin system geologia croatica 101 ample from the molve field, croatian pannonian basin.– petrol. geosci., 16/1, 41–51. doi: 10.1144/1354-079309-722 malvić, t. & velić, j. (2011): neogene tectonics in croatian part of the pannonian basin and refl ectance in hydrocarbon accumulations.– in: schattner, u. (ed.): new frontiers in tectonic research: at the midst of plate convergence. intech, rijeka, 215–238. malvić, t., velić, j. & peh, z. (2005): qualitative-quantitative analyses of the infl uence of depth and lithological composition on lower pontian sandstone porosity in the central part of bjelovar sag (croatia).– geol. croat., 58/1, 73–85. mathur, s.m. (1981): cyclic sedimentation in the vindhyan supergrup.– geological survey of india, records, 112/8, 1–6. mărunteanu, m. (1999): lithoand biostratigraphy (calcareous nannoplankton) of the miocene deposits from the outer moldavides.– geol. carpath., 50/4, 313–324. mitchum, r.m.jr. (1977): glossary of terms used in seismic stratigraphy.– in: payton, c.e. (ed.): aapg memoir, 26, seismic stratigraphy-application to hydrocarbon exploration, 205–212. pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.– basin res., 13, 359–376. pavelić, d. (2002): the south-western boundary of central paratethys.– geol. croat., 55/1, 83–92. peryt, d. (1997): calcareous nannoplankton stratigraphy of the middle miocene in the gliwice area (upper silesia, poland).– bull. pol. acad. sci., earth sci., 45, 119–131. peryt, d. (1999): calcareous nannoplankton assemblages of the badenian evaporites in the carpathian foredeep.– biuletyn państwowego instytutu geologicznego, 387, 158–161. royden, l.h. (1988): late cenozoic tectonics of the pannonian basin system.– in: royden, l.h. & horváth, f. (eds.): aapg memoir., 45, chap. 3 – the pannonian basin, 27–48. rögl, f. (1996): stratigraphic correlation of the paratethys oligocene and miocene.–mitteilungen ges. geol. bergbaustudenten österreich, 41, 65–73. rögl, f. (1998): palaeographic consideration for mediterranean and paratethys seaways (oligocene to miocene).– annals naturhistorisches museum wien, 99a, 279–310. saftić, b., peh, z., velić, j. & jüttner, i. (2001): interdepence of petrophysical properties and depth: some implications of multivariate solution on distinction between the lower pontian hydrocarbon-bearing sandstone units in the western part of the sava depression.– geol. croat., 54/2, 259–277. saftić, b., velić, j., sztano, o., juhas, g. & ivković, ž. (2003): tertiary subsurface facies, source rocks and hydrocarbon reservoirs in the sw part of the pannonian basin (northern croatia and south-western hungary).– geol. croat., 56/1, 101–122. sečen, j., perić, m. & bauk, a. (2002): mogućnosti istiskivanja nafte pomoću co2 u tercijarnoj fazi iskorištavanja ležišta [possibilities for recovery of oil by injection of co2 in the tertiary recovery phase].– naftaplin, 4, 432–442. steininger, f., rögl, f. & müller, c. (1978): geodynamik und paläogeographische entwicklung des badenien.– chronostratigraphie und neostratotypen miozän der zentralen paratethys, verlag der slowak. akad. der wissenschaften, bd. vi, 110–127. šimon, j. (1980): prilog stratigrafi ji u taložnom sustavu pješčanih rezervoara sava-grupe naslaga mlađeg tercijara u panonskom bazenu sjeverne hrvatske [contribution to stratigraphy of sandstone reservoirs depositional system in the sava group sediments in late tertiary of pannonian basin in the northern croatia – in croatian].– unpubl. phd thesis, faculty of mining, geology and petroleum engineering, university of zagreb, zagreb, 66 p. troskot-čorbić, t., velić, j. & malvić, t. (2009): comparison of the middle miocene and the upper miocene source rock formations in the sava depression (pannonian basin, croatia).– geol. croat., 62/2, 123–133. doi: 10.4154/gc.2009.11 velić, j. (2007): geologija ležišta nafte i plina [geology of oil and gas reservoirs – in croatian].– faculty of mining, geology and petroleum engineering, university of zagreb, zagreb, 342 p. velić, j., tišljar, j., dragičević, i. & blašković, i. (2000): shoreline cross-bedded biocalcarenites (middle miocene) in the podvrško-šnjegović area, mt. psunj, and their petroleum signifi cance (požega subdepression – eastern croatia).– geol. croat., 53/2, 281–293. velić, j., weisser, m., saftić, b., vrbanac, b. & ivković, ž. (2002): petroleum-geological characteristics and exploration level of the three neogene depositional megacycles in the croatian part of the pannonian basin.– nafta, 53/6–7, 239–249. velić, j., malvić, t., cvetković, m., weisser, m. & curi, v. (2008): observation useful for increase of hydrocarbon fi elds’ exploitation period within croatian part of the pannonian basin.– sgem conference “modern management of mine producing geology and environmental protection”, albena, 16.6.–20.6. 2008, proceedings, 567–574. vrbanac, b. (1996): palaeostructural and sedimentological analyses of upper pannonian sediments of ivanić grad formation in the sava depression.– unpubl. phd thesis, faculty of natural sciences (geological department), university of zagreb, zagreb, 303 p. vrbanac, b., velić, j. & malvić, t. (2010): sedimentation of deep-water turbidites in main and marginal basins in the sw part of the pannonian basin.– geol. carpath., 61/1, 55–69. doi: 10.2478/ v10096-010-0001-8 zečević, m., velić, j., sremac, j., troskot-čorbić, t. & garašić, v. (2010): signifi cance of the badenian petroleum source rocks from the krndija mt. (pannonian basin, croatia).– geol. croat., 63/2, 225–239. manuscript received april 04, 2011 revised manuscript accepted december 27, 2011 available online february 25, 2012 geologia croatica 65/1geologia croatica 102 ismail.indd 1 �ab stra ct three wells (naf-2, naf-3 and naf-101), were described and sampled in order to increase understanding of the stratigraphy and micropaleontology of the north abu qir field, nile delta, egypt. lithostratigraphic studies aided recognition of the following miocene-pliocene rock formations (from base to top); qantara formation, sidi salim formation, qawasim formation, rosetta formation, abu madi formation, kafr el sheikh formation, baltim formation, mit ghamr formation, and bilqas formation. biostratigraphic studies were based on the distribution of foraminifera through the miocene-pliocene succession. the environmental conditions of the neogene rocks of the studied wells are interpreted using the results of palaeoecological parameters (e.g. the total number of foraminifera (t.n.f) and planktonic/benthonic ratio (p/b). keywords: stratigraphy, neogene, foraminifera, north abu qir area, nile delta, egypt subsurface stratigraphy and micropaleontology of the neogene rocks, nile delta, egypt � ahmed a. ismail, mohamed boukhary and ahmed i. abdel naby department of geology, faculty of science, ain shams university, abassia 11566, cairo, egypt; (aaaismail2002@yahoo.com; moboukhary@yahoo.com and zowail2000@yahoo.com) doi: 104154/gc.2010.01 geologia croatica 63/1 1–26 15 figs. 1 tab. 4 pls. zagreb 2010 geologia croaticageologia croatica 1. introduction the nile delta is one of the most well known deltas of the world, and has attracted the attention of many geologists due to its potential gas reserves. the considerable rise of oil and gas prices has lead to further exploration in order to locate new hydrocarbon fi elds. the nile delta has in general, a featureless surface with a northward slope, except for some limited topographic features such as the khatatba positive structural and topographic features, and the westward wadi el-natrun negative element. generally, no outcrops occur on the delta surface, being mainly covered with recent mud and alluvial deposits (azzam, 1994), and also with some sand accumulations known as the turtle-backs. the structural setting of the nile delta region occupies a key position within the plate tectonic development of the eastern mediterranean and the levant. it lies on the northern margin of the african plate, which extends from the subduction zone adjacent to the cretan and cyprus arcs, to the red sea where it drifted apart from the arabian plate. the abu qir field consists of two culminations western and eastern. the western culmination is a four-way dip closure and the eastern culmination is a three-way dip closure and sealed from the eastern direction (cross-fault sealing) by the kafr el sheikh shales, which were brought in juxtaposition with the abu madi sands on the upthrown side of the fault. to the southeast, the west abu qir structure is separated from the abu qir gas field by a northeast-southwest narrow complex graben. this graben was formed by a northeast-southwest trending group of faults (badran, 1996). structurally, the abu qir and west abu qir fi elds were possibly formed in the same way, each being a rollover feature resulting from the slumping of post-miocene deltaic sediments within the giant graben, which was bounded by almost two east-west major growth faults (badran, 1996). geologia croatica 63/1geologia croatica 2 wasim formation, with a marked unconformity. it is a marine deposit of early pliocene age. the shale content increas es upward and the contact with the overlying kafr el sheikh formation is gradational in the studied wells. the type section is present in the abu madi well 1, between 3007 to 3229 m depth. the abu madi formation is the gas-producing horizont of the nile delta (e.g.p.c., 1994). the kafr el sheikh formation is composed of soft clays with a few interbeds of poorly consolidated sands with a clay ey matrix. the development of this series appears to be rather constant over the entire delta area. its upper boundary is mark ed by the fi rst appearance of the el-wastani sands which have a typical littoral fauna. the kafr el sheikh is dated as early to middle pliocene age, according to palaeontological evidence (barakat, 1982). the section has been penetrated in the kafr el sheikh well, located some 40 km ssw of the abu madi gas fi eld, in the south-central part of the onshore delta area. its thickness is 1458 m (ismail, 1984). the el wastani formation consists of thick quartzose sandstone interbedded with thin clays which thin towards the top. the upper boundary of this formation is uncertain, but it is delineated where the series becomes more sandy for several tens of metres. this formation is assigned to the late pliocene (barakat, 1982), and is 123 m thick in the el wastani well 1 (ismail, 1984). pleistocene–holocene rocks are subdivided by (e.g.p.c., 1994) into two formations; the mit ghamr formation at the base, and the bilqas formation at the top. the mit ghamr formation is composed of thick layers of sands and pebbles at its base with clay interbeds. this formation grades into the overlying? bilqas formation by the increase of interbedded clays with sands, rich in peat, and fossiliferous, with a coastal or lagoonal fauna. the bilqas formation constitutes the top basin fi ll with coastal sands and deposits from the nile fl oods. it was encountered between 20 and 484 m in the mit ghamr well, located in the southern part of the delta, on the east side of the damietta branch (schlumberger, 1984). the holocene rocks are represented by the intermittent marine transgressions that give rise to a few metres of marine sediments. both constitute the bilqas formation. plant remains and peat deposits are frequent (e.g.p.c., 1994). 3. material and methods the abu qir north field, nile delta, egypt, is located to the north west of the rosetta branch of the nile river, and is bounded between latitudes 31° 34’ n & 31° 52’ n and longitudes 30° 04’ e & 30° 26’ e (fig. 1). the number and depth of ditch cutting samples (in metres) for each well are given in table 1 below. 2. geologic setting the miocene rocks in the nile delta region were subdivided by e.g.p.c., (1994) into three formations, from base to top: the sidi salim, qawasim and rosetta. the sidi salem formation is mainly composed of green-grey clays with a few interbeds of dolomitic marls, and rare occurrences of quartzose sandstones with calcareous cement and siltstones (barakat, 1982). the age of this formation ranges from langhi an to tortonian. the lower limit is not known in the central part of the delta, but was encountered in the western offshore area (abu qir) e.g.p.c. (1994) and also in the south and southeast. it probably overlies the moghra formation or older rocks (barakat, 1982). the type section of this formation is represented by the bottom sequence at the sidi salim well 1 (located south of lake burullus), from 3592 to 4038 m depth. the upper limit is defi ned by the base of the thick conglomeratic series of the qawasim formation. offshore the sidi salim is overlain directly either by the rosetta anhydrite or by the lower pliocene clays of the kafr el sheikh formation. extensive facies changes, both lateral and up-dip, occur within the sidi salim formation in particular, and in miocene sequence in general (e.g.p.c., 1994). the qawasim formation overlies the sidi salem formation, and underlies the rosetta formation. it is composed of a thick, sandy, and conglomeratic sequence, containing a typical rare messinian fauna of the mediterranean basin (e.g.p.c., 1994). the sequence is present in the interval from 2800 to 3733 m in the qawasim 1 well, located some 14 km east of the sidi salim well 1 (schlumberger, 1984). the upper boundary of this formation is rather diffi cult to determine if the anhydrites of rosetta formation are absent. locally, it passes laterally to marine clays with pliocene fauna of kafr el sheikh formation. when the qawasim formation occurs within the basal sands of abu madi formation, where the rosetta anhydrite is missing, the criteria of separation are based on palaeontological and sedimentological evidence (barakat, 1982). large layers of anhydrite, interbedded with thin clays, represent the rosetta formation, observed in offshore well rosetta 2, ne of the mouth of the rosetta nile branch, between 678 to 2718 m depth. the presence of the rosetta anhydrite seems to be limited only to the northern and offshore part of the delta. it has not been encountered in wells drilled on the west fl ank of the delta (abu qir), but was again present offshore to the north of alexandria. a messinian age has been attributed to the rosetta anhydrite because of its position below the marine shales of defi nite early pliocene age. the formation indicates a general starvation of the sea that affected the whole mediterranean area and led to the deposition of evaporites schlumberger (1984) and hsu et al. (1973, 1977). the pliocene rocks in the nile delta region are subdivided by e.g.p.c., (1994) into three formations, from base to top: abu madi, kafr el sheikh, el wastani. the abu madi formation is represented by a thick series of sands, in part pebbly, with interbedded thin shales. the formation is crossbedded and overlies the rosetta anhydrite, and/or the qatable 1: location and number of samples taken from each well in the study area. wells depth interval (m) number of samples naf-2 1870–3445 17 naf-3 1030–3300 30 naf-101 1540–3550 24 ismail et al.: subsurface stratigraphy and micropaleontology of the neogene rocks, nile delta, egypt geologia croatica 3 2. identifying the foraminifera obtained from the different horizons and the distribution of the foraminiferal assemblages, for biostratigraphic studies of the neogene sequence. 3. delineation of palaeo-sedimentary environments, and the number of depositional cycles by using several palaeoecological parametres (e.g. the total number of foraminifera, (t.n.f.) and planktonic/benthic ratio (p/b). 4. stratigraphy correlation of the three wells located in the north abu qir field revealed ten lithostratigraphic formations (based on lithological characteristics). these are, from base to top, as follows: qantara formation, sidi salim formation, qawasim formation, rosetta formation, abu madi formation, kafr el sheikh formation, el wastani formation, baltim formation, mit ghamr formation, and bilqas formation. each rock unit is discussed below, taking into consideration the lithologic characters, stratigraphic limits, thickness, and the foraminiferal content when present. 4.1. qantara formation the top of the qantara formation is only reached by the naf101 well (figs. 3, 4 and 5), which did not reach the base of this formation. the formation is unconformably overlain by the sidi salim formation. southward, in the study area, this formation is composed of shale with argillaceous sand and limestone, as revealed by the drilling data in other wells. northward, the limestone of this formation decreases, and was replaced by clastics (shale and sand). furthermore, this formation is dated as early miocene in age, according to the presence of globigerinoides primordius as shown in (fig. 6). this age assignment is confi rmed by the presence of the early miocene dentoglobigerina altispira altispira and globorotalia these samples were washed, picked, and the different species of foraminifera have been identifi ed and examined. the aim of this study is to analyze the encountered successions stratigraphically, in order to decipher the depositional environment, depositional processes and lateral and vertical facies changes. to achieve these objectives, the following steps were followed: 1. identifying and recognizing the different rock units of the penetrated miocene–pliocene sequence based on the description of the ditch cutting samples and composite logs. fi gu re 1: a location map showing the studied wells. fi gu re 2: the generalized subsurface stratigraphic column of the nile delta region. fi gu re 3: the stratigraphic column of naf-2 well. geologia croatica 63/1geologia croatica 4 obesa. also, there are several other planktonic species associated with these fossils (e.g. globigerinoides bisphericus, neogloboquadrina continuosa, globorotalia archeomerandii, globigerina brazieri, globigerina praebulloides, orbulina cf. suturalis, orbulina universa and globigerinoides trilobus immaturus). moreover, there are several benthic species associated with the previous planktonic species e.g. (bolivina dilatata, gyroidinoides soldanii, nonionina scapha, bulimina elongata, lagena sulcata, globocassidulina elongata, uvigerina semiornata, nonionella auris, lenticulina cultra ta, cibicides refulgens and neoeponides sp). 4.2. sidi salim formation this formation unconformably overlies the qantara formation and underlies the qawasim formation. the bottom of this formation was not reached in two wells (naf-2 and naf-3). its thickness in well naf-101 is 460 m. this formation is composed of intercalations of shale, sand, clay, with rare occurrences of white, bioclastic limestone. this limestone occurs less frequently and passes gradually towards the northeast of the study area. the formation is of middle miocene age, based on the presence of globigerinoides bollii at the top of this formation, which could represent a useful datum in the mediterranean region, where the globigerinoides fohsi lineage is not developed (bolli & saunders, 1985). however, the absence of the three upper biozones of middle miocene age (globigerinoides ruber, neogloboquadrina mayeri and globorotalia menardii) biozones indicates a hiatus between the middle miocene and the late miocene as shown on the distribution chart of the naf-101 well (fig. 12). however, the presence of praeorbulina glomerosa curva and praeorbulina glomerosa glomerosa species supports the age assignment of this formation, which directly underlies the upper miocene sediments. this also indicates a similar hiatus in the formation as shown in the naf-3 well (fig. 11). accordingly, this formation is dated from the early middle miocene to late miocene. fi gu re 4: the stratigraphic column of naf-3 well. fi gu re 5: the stratigraphic column of naf-101 well. fi gu re 6: the miocene–pliocene planktonic foraminfera zones and subzones (after bolli & saunders, 1985). e – early, m – middle, l – late. ismail et al.: subsurface stratigraphy and micropaleontology of the neogene rocks, nile delta, egypt geologia croatica 5 also, there are several planktonic species associated with the above species (e.g. globigerinoides pseudobesa, globigerina ciperoensis ciperoensis, dentoglobigerina venezuelana, globigerina woodi, globigerina nilotica, orbulina universa, orbulina bilobata, globigerinoides trilobus immaturus, globigerinoides obliquus extremus and globigerinella obesa). moreover, there are several benthic species associated with the planktonic taxa listed above (e.g. quinqueloculina bosciana, bolivina hebes, ammonia beccarii, bulimina elongata, asterigerina planorbis, nonionellina cf. labradorica, gyroidinoides soldanii, pullenia quinqueloba, elphidium macellum and neoeponides sp.). 4.3. qawasim formation this formation overlies the sidi salim formation and underlies the rosetta formation. the thickness of this formation increases northward (25 m in the naf-101 well, and 100.5 m in the naf-2 well (fig. 3)). also, its thickness is 34 m in naf-3 well. this formation is composed of sand to sandstone with a few interbeds of clay. also, there are several planktonic species associated with this formation (e.g. globigerinoides trilobus immaturus, globigerinoides bullatus, globigerinoides obliquus extremus, globigerina nilotica, and orbulina universa). moreover, there are several benthic species associated with the planktonics (e.g. cibicides gibbosus, alabamina sp., buccella sp., uvigerina cf. asperula, bolivina hebes, and nonionina scapha). the formation has been dated as late miocene (messinian), according to its stratigraphic position (azzam, 1990; e.g.p.c., 1994; and abu el enein, 1990) and also on both lithological and palaeontological characteristics (ismail, 1984). in the present study, this formation is also dated as late miocene according to its stratigraphic position between the underlying sidi salim formation of early middle miocene to late miocene and the overlying rosetta formation of late miocene. 4.4. rosetta formation this formation overlies the qawasim formation and underlies the abu madi formation. the thickness of this formation decreases northward (99 m in naf-101 well and 28 m in naf-2 well). also, its thickness is 50 m in naf-3 well. it is composed of sand with occurrences of anhydrite and clay. deposition of evaporites in this formation indicates a general regression of the mediterranean, and this also explains the low content of planktonic foraminiferal species (e.g. globigerinoides tenellus, globigerinoides obliquus extremus, globigerina nilotica, orbulina bilobata and orbulina universa). also, there are few benthic species associated with the planktonics (e.g. gyroidinoides soldanii, alabamina sp., uvigerina semiornata and loxostomum pseudodigitale). the age of the rosetta formation is late miocene (messinian) due to its stratigraphic position below the upper miocenelower pliocene marine sediments (abu madi formation). also, the presence of sphaeroidinellopsis disjuncta in the topmost part of this formation is further evidence for this age assignment. this species of sphaeroidinellopsis has been used repeatedly as a zonal marker (bolli & saunders, 1985). the highest occurrence of sphaeroidinellopsis disjuncta denotes the top of the miocene (bolli & saunders, 1985). 4.5. abu madi formation this formation overlies the rosetta formation and/or the sidi salim formation with a marked unconformity and underlies the kafr el sheikh formation. the thickness of this formation increases northward (138 m in naf-101 well and 234 m in naf-2 well). also, its thickness attains 155 m in naf-3 well (fig. 4). it is mainly composed of intercalations of sand, clay, and shale. the age assignment of this formation is controversial, where it is dated as late miocene (messinian), on a sedimentological basis, by effat & gezeiry (1986) and deibis et al. (1986). however, abu el enein (1990) stated that the transgression in the early pliocene was responsible for deposition of the abu madi formation. in the present study, this formation is dated as early pliocene in the studied three wells, according to the presence of globorotalia margaritae, which is a widely recognized index species for the pliocene (bolli & saunders, 1985). on palaeomagnetic evidence (cita, 1975 and lourens et al., 2004), the age of this species ranges from 5.01 to 4.14 ma. it is a cosmopolitan species occurring in both deep and shallow waters (bolli & saunders, 1985). the presence of globorotalia exilis with globorotalia margaritae terminates the early pliocene according to bolli & saunders (1985). the occurrence of sphaeroidinellopsis disjuncta in the top of the abu madi formation in the naf-2 well suggests that this formation is of late miocene age. this age assignment is confi rmed by the occurrence of globorotalia margaritae margaritae at the base of the overlying kafr el sheikh formation. also, there are several planktonic species associated with the species listed above (e.g. globigerinoides quadrilobatus, globigerinoides obliquus extremus, globigerinoides ruber, globigerinoides bulloideus, globigerinoides tenellus, globigerinoides trilobus immaturus, globigerina quinqueloba, globigerina nilotica, globigerina apertura, globigerinella obesa, orbulina universa and catapsydrax parvulus). moreover, there are several benthic species associated with the planktonic taxa (e.g. bolivina dilatata, loxostomum perforatum, buccella sp., nonionina scapha, lenticulina smiley, alabamina sp., cibicidoides sp., eponides polygonus, asterigerina planorbis and bulimina elongata). from the previous discussion, this formation could be classifi ed as late miocene–early plio cene. 4.6. kafr el sheikh formation this formation overlies the abu madi formation and underlies the el wastani formation. the thickness of this formation is 1121 m in the naf-101 well and 1149 m in the naf-2 well. also, its thickness attains 1282 m in the naf-3 well. the formation is composed of shale-clay intercalations with some minor occurrences? of sands, siltstones, argillaceous limestones, and dolomites. also, there are several planktonic species present in this formation (e.g. globigerinoides obliqua, globigerinoides trilobus trilobus, globigerina falcongeologia croatica 63/1geologia croatica 6 ensis, globigerina nilotica, globigerina apertura, turborotalia humilis, globorotalia exilis, globorotalia acostaensis acostaensis, bella praedigitata and catapsydrax parvulus). moreover, there are several benthic species associated with the planktonics (e.g. nonion affi nis, anomalina grosserugosa, bulimina elongata, gyroidinoides soldanii, bolivina hebes, ammonia beccarii, cibicidoides sp., cassidulina brocha, pullenia osloensis and uvigerina semiornata). the kafr el sheikh formation is dated as early-middle pliocene according to palaeontological (barakat, 1982) and geophysical data by badran (1996). it is worthmentioning that during early-middle pliocene, the marine transgression that began during the early pliocene, had been extended over the entire mediterranean area (azzam, 1994). the kafr el sheikh formation is ascribed to early-late pliocene (deibis et al., 1986). also, effat & gezeiry (1986) assigned the same age, to the formation based on lithology and wireline logs. rizzini et al. (1978) mentioned that the upper part of this formation belongs to the middle pliocene. 4.7. el wastani formation this formation overlies the kafr el sheikh formation and underlies the baltim formation. the thickness of this formation increases northward (156 m in naf-101 well, and 301 m in naf-2 well). also, its thickness attains 124 m in naf-3 well. this formation is composed of intercalations of sand, shale, clay, with some dolomite and limestone. the nonclastic facies (carbonates) increase northward. there are sevefi gu re 7: the planktonic foraminiferal distribution chart of naf-2 well. ismail et al.: subsurface stratigraphy and micropaleontology of the neogene rocks, nile delta, egypt geologia croatica 7 ral planktonic species present in this formation (e.g. globigerinoides elongatus, globigerinoides trilobus sacculifer, globigerina rubescens, glo bigerina bulloides, orbulina universa and globigerinella obesa). there are also several benthic species associated with the planktonic forms (e.g. nonion asterizans, ammonia tepida, natlandia cf. secasensis, eponidella cf. libertadensis, lenticulina reedi, bulimina elongata, cassidulina brocha, ammonia umbonata, bolivina hebes and pullenia osloensis). the age of this formation is late pliocene, based on geophysical data (badran, 1996 and azzam, 1994). these authors mentioned that the regression of the sea heralded the end of the sedimentation cycle of the pliocene. 4.8. baltim formation this formation overlies the el wastani formation and underlies the mit ghamr formation. the thickness of this formation is 690 m in naf-101 well, 986 m in naf-2 well and 1492 m in the naf-3 well. the baltim formation is composed of intercalations of clay, sand, shale, with thin bioclastic limestones. planktonic foraminiferal species present in this formation include; globigerinella obesa, globigerino ides quadrilobatus, globigerinoides trilobus immaturus, glo bigerinoides trilobus trilobus, globigerinoides obliquus extremus, globigerinoides ruber, globorotalia acostaensis aco staensis, globigerina falconensis, globigerina quinqueloba and orbulina universa. there are also several benthic speci es fi gu re 8: the planktonic foraminiferal distribution chart of naf-3 well. geologia croatica 63/1geologia croatica 8 associated with the planktonics (e.g. elphidium macellum, lenticulina hughesi, buccella sp., bolivina hebes, cibicidoides sp., uvigerina semiornata, bulimina elongata, ammonia beccarii, asterigerina planorbis and nonionina sca pha). these foraminiferal species are shown on the distribution charts (figs. 7, 8, 9, 10, 11 and 12). the formation has been dated as early pleistocene based on palaeontological studies (deibis et al., 1986). in the north abu qir area, the age of this formation ranges from pleistocene to recent as recorded in the two wells (naf-3 well & naf-101 well). 4.9. mit ghamr formation this formation overlies the baltim formation and underlies the bilqas formation. the thickness of this formation decreases northward (661 m in naf-101 well and 482.5 m in naf-2 well). also, its thickness attains 624 m in the naf-3 well. this formation is composed of intercalations of clay, sand, and silt, with some limestone. no foraminifera have been recorded in this formation which may be partly due to the number of samples. ismail (1984) dated this formation fi gu re 9: the planktonic foraminiferal distribution chart of naf-101 well. ismail et al.: subsurface stratigraphy and micropaleontology of the neogene rocks, nile delta, egypt geologia croatica 9 as late pliocene to quaternary, while azzam (1994) ascribed it to the pleistocene age. moreover, badran (1996) dated it as late pliocene to pleistocene in age. in the study area, this formation is dated pleistocene to recent throughout, based on correlation with neighbouring areas. 4.10. bilqas formation this formation covers the whole delta region. in the study area, it is present at the top of all wells. however, it is diffi cult to differentiate it from the underlying mit ghamr formation. this formation is composed of sand interbedded with clay rich in molluscan fragments. the clays contain vegetable remains and carbonaceous matter. it is dated as holocene by barakat (1982) and badran (1996). azzam (1994) mentioned that during the holocene a marine transgression covered most of the northern delta area and gave rise to a few metres of marine sediments capped by agricultural soil. rizzini et al. (1976) and abu el enein (1990) ascribed this formation to the same age, based on the faunal association. in the study area, this formation is dated as being pleistocene to recent in age. fi gu re 10: the benthic foraminiferal distribution chart of naf-2 well. geologia croatica 63/1geologia croatica 10 5. taxonomic list order foraminiferida eichwald, 1830 quinqueloculina bosciana d’orbigny, 1938 (pl. 1, fig. 1) 1938. quinqueloculina bosciana d’orbigny, p. 191, pl. 11, fi gs. 11–24 1990. quinqueloculina bosciana d’orbigny-abu el enein, pl. 2, fi g. 13 nodosaria raphanistrum (linne), 1758 (pl. 1, fig. 2) 1758. nautilus raphanistrum linne, p. 710. 1930. nodosaria raphanistrum (linne)-macfadyen, p. 74, pl. 2, fi g. 36 lagena striata (d’orbigny), 1839 (pl. 1, fig. 3) 1839. oolina striata d’orbigny, p. 21, pl. 5, fi g. 12 1996. lagena striata (d’orbigny)-osman, pl. 2, fi g.9 fi gu re 11: the benthic foraminiferal distribution chart of naf-3 well. ismail et al.: subsurface stratigraphy and micropaleontology of the neogene rocks, nile delta, egypt geologia croatica 11 lagena sulcata (walker and jacob), 1798 (pl. 1, fig. 4) 1798. serpula sulcata walker and jacob, p. 634, pl. 14, fi g. 18 1985. lagena sulcata (walker and jacob)-luger, p. 81, pl. 4, fi g.6 globorotalia acostaensis acostaensis blow, 1959 (pl. 1, figs. 5–6) 1959. globorotalia acostaensis blow, p. 208, pl. 17, fi gs. 106a–c 1985. globorotalia acostaensis acostaensis blow-bolli & saunders, p. 210, pl. 27, fi gs. 10–11, pl. 28, fi gs. 16–24 globorotalia archeomenardii bolli, 1957 (pl. 1, fig. 7) 1957. globorotalia archeomenardii bolli, p. 119, pl. 28, fi gs. 11a–c 1983. globorotalia archeomenardii bolli-kennett & srinivasan, pl. 28, fi gs. 3–5 fi gu re 12: the benthic foraminiferal distribution chart of naf-101 well. geologia croatica 63/1geologia croatica 12 ismail et al.: subsurface stratigraphy and micropaleontology of the neogene rocks, nile delta, egypt geologia croatica 13 neogloboquadrina continuosa (blow, 1959) (pl. 1, figs. 8–9) 1959. globorotalia opima bolli subsp. continuosa blow, p. 218, pl. 19, fi gs. 125a–c 1985. globorotalia continuosa blow-bolli et al., p. 204, pl. 28, fi gs. 8–14. globorotalia exilis blow, 1969 (pl. 1, fig.10) 1969. globorotalia cultrata exilis blow, p. 396, pl. 7, fi gs. 1–3, pl. 42, fi gs. 1–5 1983. globorotalia exilis, blow-bolli et al., p. 228, fi gs. 33.4, 35.9–11 globorotalia humerosa humerosa takayanagi & saito, 1962 (pl. 1, figs. 11–13) 1962. globorotalia humerosa humerosa takayanagi & saito, p. 78, pl. 28, fi gs. 1a–c 1985. globorotalia humerosa humerosa takayanagi & saito-bolli et al, p. 208, fi gs. 27.8a–c, p. 209, fi gs. 28.15a–c globorotalia margaritae margaritae bolli & bermudez, 1965 (pl. 1, figs. 14–16) 1965. globorotalia margaritae bolli & bermudez, p. 132, pl. 1, fi gs. 16–18 1985. globorotalia margaritae margaritae bolli & bermudez-bolli et al., p. 218, fi gs. 30.9–14g globorotalia peripheroronda blow & banner, 1966 (pl. 1, figs. 17–18) 1966. globorotalia peripheroronda blow & banner, p. 294, pl. 1, fi gs. 1a–c 1983. globorotalia peripheroronda blow & bannerkennett & srinivasan, pl. 22, fi gs. 1–3 globorotalia pseudopima blow, 1969 (pl. 2, fig. 19) 1969. globorotalia acostaensis pseudopima blow, p. 387, pl. 35, fi gs. 1–3 1985. globorotalia pseudopima blow-bolli et al., p. 208, fi g. 27.7g, p. 209, fi gs. 28.10–12g plate 1 bar scale = 100 µm 1 quinqueloculina bosciana, (d’orbigny 1839), pleistocene-recent, baltim, sample from 1030 m, naf-3 well. 2 nodosaria raphanistrum, linne 1758, pleistocene-recent, baltim, sample from 1030 m, naf-3 well. 3 lagena striata, (d’orbigny, 1839), pliocene, kafr el sheikh, sample from 1790 m, naf-3 well. 4 lagena sulcata, (walker and jacob, 1798), early miocene, qantara, sample from 3550 m, naf-101 well. 5–6 globorotalia acostaensis acostaensis, blow 1959, 5. ventral view, pleistocene-recent, baltim, sample from 1320m, naf-3 well. 6. dorsal view, early pliocene, kafr el sheikh, sample from 3075m, naf-2 well. 7 globorotalia archeomenardii, bolli 1957, ventral view, pliocene, kafr el sheikh, sample from 2680 m, naf-101 well. 8–9 neogloboquadrina continuosa, blow 1959, 8. ventral view, early miocene, qantara, sample from 3530m, naf-101 well. 9. dorsal view, early miocene, qantara, sample from 3530m, naf-101 well. 10 globorotalia exilis, blow 1969, ventral view, pliocene, kafr el sheikh, sample from 2680 m, naf-101 well. 11–13 globorotalia humerosa humerosa, takayanagi & saito 1962, 11. ventral view, early miocene, qantara, sample from 3530m, naf-101 well. 12. side view, early miocene, qantara, sample from 3530m, naf-101 well. 13. dorsal view, early miocene, qantara, sample from 3530m, naf-101 well. 14–16 globorotalia margaritae margaritae, bolli & bermudez 1965, 14. ventral view, pliocene, kafr el sheikh, sample from 2680 m, naf-101 well. 15. side view, pliocene, kafr el sheikh, sample from 3075 m, naf-2 well. 16. dorsal view, pliocene, abu madi, sample from 2800 m, naf-3 well. 17–18 globorotalia peripheroronda, blow & banner 1966, 17. ventral view, pliocene, kafr el sheikh, sample from 1980m, naf-101 well. 18. dorsal view, pliocene, kafr el sheikh, sample from 19800m, naf-101 well. 19 globorotalia pseudopima, blow 1969, ventral view, pliocene, kafr el sheikh, sample from1980 m, naf-101 well. 20 globorotalia scitula praescitula, blow 1959, ventral view, early pliocene, kafr el sheikh, sample from2775 m, naf-2 well. 21 globorotalia scitula scitula, brady 1884, ventral view, early miocene, qantara, sample from 3530 m, naf-101 well. 22 dentoglobigerina altispira altispira, cushman & jarvis 1936, ventral view, early miocene, qantara, sample from 3550 m, naf-101 well. 23 globigerina ciperoensis ciperoensis, bolli 1954, ventral view, middle miocene, sidi salim, sample from 3300 m, naf-3 well. geologia croatica 63/1geologia croatica 14 ismail et al.: subsurface stratigraphy and micropaleontology of the neogene rocks, nile delta, egypt geologia croatica 15 globorotalia scitula praescitula blow, 1959 (pl. 2, fig. 20) 1957. globorotalia scitula praescitula blow, p. 221, pl. 19, fi gs. 128a–c 1985. globorotalia scitula praescitula blow-bolli et al., p. 219, fi gs. 31.6a–c globorotalia scitula scitula (brady, 1884) (pl. 2, fig. 21) 1882. pulvinulina scitula brady, p. 716. 1884. globorotalia scitula scitula brady, pl. 103, fi gs. 7a–c 1985. globorotalia scitula scitula brady-bolli et al., p. 219, fi gs. 31.3–4g dentoglobigerina altispira altispira, (cushman & jarvis 1936) (pl. 2, fig. 22) 1936. globoquadrina altispira cushman & jarvis, p. 5, pl. 1, fi gs. 13a–c 1983. globoquadrina altispira altispira cushman & jarvis-bolli & saunders, p. 183, fi g. 15 globigerina ciperoensis ciperoensis bolli, 1957 (pl. 2, fig. 23) 1957. globigerina ciperoensis angustiumbilicata bolli, p. 109, pl. 22, fi gs. 12a–c 1985. globigerina ciperoensis ciperoensis bolli-bolli et al., p. 178, fi gs. 13.1–3g globigerina nilotica viotti & mansour, 1969 | (pl. 2, figs. 1–3) 1969. globigerina nilotica viotti & mansour, p. 447, pl. 6, fi gs. 1–7 globigerina praebulloides blow, 1959 (pl. 2, fig. 4–6) 1957. globigerina praebulloides blow, p. 180, pl. 8 fi gs. 47a–c; pl. 9, fi g. 48 1983. globigerina praebulloides blow-kennett & srinivasan, pl. 6, fi gs. 1–3 plate 2 bar scale = 100 µm 1–3 globigerina nilotica, viotti & mansour, 1969, 1. ventral view, pliocene, el wastani, sample from 1540, naf-101 well. 2. side view, late miocene, rosetta, sample from 2970, naf-3 well. 3. dorsal view, late miocene, rosetta, sample from 2970, naf-3 well. 4–6 globigerina praebulloides, blow 1959, 4. ventral view, middle miocene, sidi salim, sample from 3300, naf-3 well. 5. side view, mid.-lat. miocene, qawasim, sample from 3300, naf-3 well. 6. dorsal view, middle miocene, rosetta, sample from 3030, naf-101 well. 7–8 globigerina rubescens, honza, 1980, 7. ventral view, late pliocene, kafr el sheikh, sample from 1960 m, naf-2 well. 8. dorsal view, late pliocene, kafr el sheikh, sample from 1960 m, naf-2 well. 9–12 globigerinoides bisphericus, todd 1954, 9. ventral view, early miocene, qantara, sample from 3530 m, naf-101 well. 10. dorsal view, early miocene, qantara, sample from 3530 m, naf-101 well. 11. side view, early miocene, qantara, sample from 3530 m, naf-101 well. 12. side view, early miocene, qantara, sample from 3530 m, naf-101 well. 13–14 globigerinoides bollii, blow 1959, 13. ventral view, middle pliocene, kafr el sheikh, sample from 2370 m, naf-2 well. 14. dorsal view, late pliocene, kafr el sheikh, sample 1960 m, naf-2 well. 15–16 globigerinoides elongatus, d’orbigny 1926, 15. ventral view, late pliocene, kafr el sheikh, sample from 1960 m, naf-2 well. 16. dorsal view, late pliocene, kafr el sheikh, sample from 1960 m, naf-2 well. 17–19 globigerinoides obliquus extremus, bolli & bermudez 1965, 17. ventral view, late miocene, rosetta, sample from 3030, naf-101 well. 18. side view, late pliocene, kafr el sheikh, sample from 1960m, naf-2 well. 19. dorsal view, late pliocene, kafr el sheikh, sample from 1969m, naf-2 well. 20 globigerinoides obliquus obliquus, bolli 1957, ventral view, pliocene, kafr el sheikh, sample from 2680 m, naf-101 well. 21 globigerinoides primordius, blow & banner 1962, ventral view, early miocene, qantara, sample from 3550 m, naf-101 well. 22–23 globigerinoides ruber, d’orbigny 1839, 22. ventral view, early pliocene, kafr el sheikh, sample from2625 m, naf-2 well. 23. dorsal view, middle miocene, sidi salim, sample from 3300m, naf-3 well. 24–25 globigerinoides trilobus immaturus, le roy 1939, 24. ventral view, middle miocene, sidi salim, sample from 3300m, naf-3 well. 25. dorsal view, middle miocene, sidi salim, sample from 3300 m, naf-3 well. geologia croatica 63/1geologia croatica 16 globigerina rubescens hofker, 1956 (pl. 2, figs. 7–8) 1956. globigerina rubescens hofker, p. 234, pl. 32, fi g. 26; pl. 35, fi gs. 18–21 1983. globigerina rubescens hofker-kennett & srinivasan, pl. 9, fi gs. 7–9 globigerinoides bisphericus todd, 1954 (pl. 2, figs. 9–12) 1954. globigerinoides bispherica todd, p. 681, pl.1, fi gs. 1a–c 1983. globigerinoides bisphericus todd-bolli & saunders, p. 199, fi gs. 24.8; 7,9,12 globigerinoides bollii blow, 1959 (pl. 2, figs. 13–14) 1957. globigerinoides bollii blow, p. 189, pl. 10, fi gs. 65a–c 1983. globigerinoides bollii blow-bolli et al., p. 193, fi gs. 20.8a–c globigerinoides elongatus (d’orbigny), 1926 (pl. 2, figs. 15–16) 1926. globigerina elongata d’orbigny, p. 277. 1985. globigerinoides elongatus (d’orbigny)-bolli et al., p. 193, fi gs. 20.4a–c globigerinoides obliquus extremus bolli & bermudez, 1965 (pl. 2, figs. 17–19) 1965. globigerinoides obliquus extremus bolli & bermudez, p. 139, pl. 1, fi gs. 10–12 1985. globigerinoides obliquus extremus bolli & bermudez-bolli & saunders, p. 194, pl. 20, fi g. 11 globigerinoides obliquus obliquus bolli, 1957 (pl. 2, fig. 20) 1957. globigerinoides obliquus bolli, p. 113, pl.25, fi gs. 19a–c 1983. globigerinoides obliquus obliquus bolli-bolli & saunders, p. 194, pl. 20, fi g. 12 globigerinoides primordius blow & banner, 1962 (pl. 2, fig. 21) 1962. globigerinoides primordius blow & banner, p. 15, pl. ix, fi gs. dd–ff 1983. globigerinoides primordius blow & bannerkennett & srinivasan, pl. 11, fi gs. 1–3 globigerinoides ruber d’orbigny, 1839 (pl. 2, figs. 22–23) 1839. globigerinoides ruber d’orbigny, p. 19, pl. 3, fi gs. 8a–c 1983. globigerinoides ruber d’orbigny-bolli et al., p. 193, fi gs. 20.1, 2 globigerinoides trilobus immaturus le roy, 1939 (pl. 2, figs. 24–25; pl. 3, fig. 1) 1939. globigerinoides sacculifer (brandy) var. immaturus le roy, p. 263, pl. 3, fi gs. 19–21 1983. globigerinoides trilobus immaturus leroy-bolli et al., p. 193, fi gs. 20.14a–c globigerinoides trilobus sacculifer brady, 1877 (pl. 3, fig. 2) 1877. globigerina sacculifera brady, p. 535. 1985. globigerinoides trilobus sacculifer brady-bolli et al., p. 193, fi gs. 20.13a–b globigerinoides trilobus trilobus (reuss), 1850 (pl. 3, figs. 3–5) 1850. globigerina triloba reuss, p. 374, pl. 47, fi gs. 11a–c 1985. globigerinoides trilobus trilobus (reuss)-bolli et al., p. 193, fi gs. 20.15a–b sphaeroidinellopsis disjuncta finlay, 1940 (pl. 3, figs. 6–8) 1939. sphaeroidinellopsis disjuncta finlay, p. 467, pl. 67, fi gs. 224–228 1983. sphaeroidinellopsis disjuncta finlay-kennett & srinivasan, pl. 51, fi gs. 3–5 orbulina bilobata d’orbigny, 1846 (pl. 3, fig. 9) 1846. orbulina bilobata d’orbigny, p. 164, pl. 9, fi gs. 11–14 1983. orbulina bilobata d’orbigny, kennett & srinivasan, p. 88, pl. 20, fi gs. 7–9 orbulina cf. suturalis bronnimann (pl. 3, fig. 10) 1951 orbulina suturalis bronnimann, p. 135, fi gs. 2–4 1985 orbulina suturalis bronnimann-bolli & saunders, p. 201, fi g. 23 (2) orbulina universa d’orbigny, 1839 (pl. 3, fig. 11) 1839. orbulina universa d’orbigny, p. 3, pl. 1, fi g. 1 1983. orbulina universa d’orbigny-kennett & srinivasan, pl. 18, fi g. 2; pl. 20, fi gs. 4–6 praeorbulina glomerosa curva blow, 1956 (pl. 3, figs. 12–13) 1956. praeorbulina glomerosa curva blow, p. 62, text fi g. 1, no. 9–14 ismail et al.: subsurface stratigraphy and micropaleontology of the neogene rocks, nile delta, egypt geologia croatica 17 1983. praeorbulina glomerosa curva blow-kennett & srinivasan, pl. 18, fi gs. 3–4 praeorbulina glomerosa glomerosa blow, 1956 (pl. 3, figs. 14) 1956. praeorbulina glomerosa glomerosa blow, p. 64, text fi g. 1, 15–19. fi g. 2, 1–2 1983. praeorbulina glomerosa glomerosa blow-kennett & srinivasan, pl. 18, fi gs. 5–7 bolivina hebes macfadyen, 1930 (pl. 3, fig. 15) 1930. bolivina hebes mackfadyen p. 59, pl. ii, fi gs. 5a–c 1999. bolivina hebes mackfadyen-abul-nasr & salama, p. 127, fi g. 17 (13) cassidulina laevigata d’orbigny, 1826 (pl. 3, fig. 16) 1826 cassidulina laevigata d’orbigny, p. 282, pl. xv, fi gs. 4–5 1999 cassidulina laevigata d’orbigny-abul-nasr & salama, p. 127, fi g. 17 (20) globocassidulina oblonga (reuss), 1850 (pl. 3, fig. 17) 1850. cassidulina oblonga, reuss, p. 376, pl. 48, fi gs. 5–6 1982. globocassidulina oblonga (reuss)-agip, p. 43, fi g. 7 bulimina elongata d’orbigny, 1826 (pl. 3, fig. 18) 1826. bulimina elongata d’orbigny, p. 269 1990. bulimina elongata d’orbigny-abu el enein, pl. 8, fi g. 19 uvigerina cf. asperula czjzek, 1848 (pl. 3, fig. 19) 1848 uvigerina asperula czjzek, p. 146, pl. 13, fi gs. 14–15 1965 uvigerina asperula czjzek –souaya, p. 317, pl. 2, fi g. 26 uvigerina semiornata, d’ orbigny 1840 (pl. 3, fig. 20) 1840 uvigerina semiornata, d’ orbigny, p. 16. 1999 uvigerina semiornata, d’ orbigny-abul-nasr & salama, p. 129, fi g. 18 (9). fursenkoina schreibersiana (czjzek, 1848) (pl. 3, fig. 21) 1999 fursenkoina schreibersiana (czjzek)-abul-nasr &salama, p. 129, fi g. 18 (2) nodosarella sp. (pl. 3, fig. 22) cancris auriculus (fichtel & moll), 1798 (pl. 3, fig. 23) 1798. nautilus auriculus fichtel & moll 1798, p. 108, pl. 20, fi gs. a–c 1985. cancris auriculus (fichtel & moll 1798)-papp & schmid, p. 61, pl. 52, fi gs. 7–13 natlandia cf. secasensis mcculloch 1977 (pl. 3, fig. 24) 1977. natlandia secasensis mcculloch, p. 346 valvulineria complanata (d’orbigny, 1846) (pl. 3, figs. 25–26) 1846. rosalina complanata d’orbigny, p. 175, pl. 10, fi gs. 13–15 1965. valvulineria complanata (d’orbigny)-souaya, p. 44, pl. 1, fi gs. 9a–b neoeponides sp. (pl. 3, fig. 27; pl. 4, fig. 1) cibicidoides sp. (pl. 4, fig. 2) eponidella cf. libertadensis cushman & hedberg, 1935 (pl. 4, fig. 3) 1935 eponidella libertadensis cushman & hedberg, p. 13 asterigerina planorbis d’orbigny, 1846b (pl. 4, figs. 4–5) 1846. asterigerina planorbis d’orbigny, p. 205, pl. 11, fi gs. 1–3 1931. discorbis planorbis (d’orbigny)-macfadyen, p. 97, pl. 4, fi gs. 8a–c 1965. asterigerina planorbis d’orbigny-souaya, p.34. nonionellina labradorica (dawson, 1860) (pl. 4, figs. 6–7) 1860. nonionina labradorica dawson, p. 191 1988. nonionellina labradorica (dawson)-loeblich & tappan, p. 617, pl. 689, fi gs. 8–17 melonis pompiliodes (fichtel & moll, 1798) (pl. 4, figs. 8–9) 1798. natilus pompiliodes fichtel & moll, p. 31, pl. 2, fi gs. a–c 1969. nonion pompiliodes (fichtel & moll)-omara & ouda, p.586, pl. 2, fi gs. 31–32 geologia croatica 63/1geologia croatica 18 ismail et al.: subsurface stratigraphy and micropaleontology of the neogene rocks, nile delta, egypt geologia croatica 19 1999 melonis pompiliodes (fichtel & moll)-abulnasr & salama, p. 130, fi g. 19 (13–14) pullenia osloensis feyling & hassan, 1954 (pl. 4, figs. 10–11) 1954. pullenia osloensis feyling & hassan, p. 194, pl. 1, fi gs. 33–35 1983. pullenia osloensis feyling & hassan-belanger & berggren, p. 341, pl. 5, fi gs. 2a–3b pullenia quinqueloba (reuss) 1851, (pl. 4, fig.12) 1851. pullenia quinqueloba reuss, p. 71, pl, v, fi g. 31 1884. pullenia quinqueloba (reuss)-brady, p. 617, pl. 1xxxiv, fi gs. 14–15 alabamina sp. (pl. 4, fig. 13) gyroidinoides soldanii d’orbigny 1825, (pl. 4, figs. 14–15) 1825. gyroidina soldanii d’orbigny, p. 278 1990. gyroidina soldanii d’orbigny-abu el enein, pl. 12, fi g. 12 buccella sp. (pl. 4, fig. 16) ammonia beccarii (linne), 1758 (pl. 4, figs. 17–20) 1758. nautilus beccarii linne, p. 1162 1930. rotalia beccarii (linne)-macfadyen, p. 103 1990. ammonia beccarii (linne)-abu el enein, pl. 13, fi g. 4 ammonia ikebei (inoue & nakaseko), 1951 (pl. 4, figs. 21–22) 1949. rotalia ikebei inoue & nakaseko, p. 10, fi gs. 4a–c 1980. ammonia ikebei (inoue & nakaseko)-billman et al., p. 88, pl. 11, fi g. 16 plate 3 bar scale = 100 µm 1 globigerinoides trilobus immaturus, le roy 1939, side view, middle miocene, sidi salim, sample from 3300 m, naf-3 well. 2 globigerinoides trilobus sacculifer, brady 1877, ventral view, late pliocene, el wastani, sample from 1630 m, naf-3 well. 3–5 globigerinoides trilobus trilobus, reuss 1850, 3. ventral view, early miocene, qantara, sample from 3550 m, naf-101 well. 4. dorsal view, late pliocene, kafr el sheikh, sample 1960 m, naf-2 well. 5. side view, late pliocene, kafr el sheikh, sample 1960 m, naf-2 well. 6–8 sphaeroidinellopsis disjuncta, finlay 1940, 6. ventral view, late miocene, rosetta, sample from 3030 m, naf-101 well. 7. dorsal view, late miocene, rosetta, sample from 2970 m, naf-3 well. 8. side view, late miocene, rosetta, sample from 2970 m, naf-3 well. 9 orbulina bilobata, d’orbigny 1846, dorsal view, early pliocene, kafr el sheikh, sample from 3075 m, naf-2 well. 10 orbulina cf. suturalis bronnimann, 1951 middle miocene, sidi salim, sample from 3300 m, naf-3 well. 11 orbulina universa, d’orbigny 1939, middle miocene, sidi salim, sample from 3300 m, naf-3 well. 12–13 praeorbulina glomerosa curva, blow 1956, 12. ventral view, pliocene, kafr el sheikh, sample from 2680 m, naf-101 well. 13. middle miocene, sidi salim, sample from 3300 m, naf-3 well. 14 praeorbulina glomerosa glomerosa, blow 1956, middle miocene, sidi salim, sample from 3500 m, naf-101well. 15 bolivina hebes macfadyen 1930, late pliocene, el wastani, sample from 1870 m, naf-2 well. 16 cassidulina laevigata d’ orbigny, 1826, pliocene, kafr el sheikh, sample from 1640 m, naf-3 well. 17 globocassidulina oblonga, (reuss 1850), early miocene, qantara, sample from 3550 m, naf-101 well. 18 bulimina elongata d’orbigny 1826, late pliocene, el wastani, sample from 1925 m, naf-2 well. 19 uvigerina cf. asperula czjzek, 1848 late pliocene, el wastani, sample from 1870 m, naf-2 well. 20 uvigerina semiornata d’orbigny, 1840, pliocene, kafr el sheikh, sample from 1790 m, naf-3 well. 21 fursenkoina schreibersiana (czjzek, 1848), pliocene, kafr el sheikh, sample from 1460 m, naf-3 well. 22 nodosarella sp., pliocene, kafr el sheikh, sample from 1640 m, naf-3 well. 23 cancris auriculus, (fichtel & moll 1798), ventral view, pleistocene-recent, baltim, sample from 1550 m, naf-3 well. 24 natlandia cf. secasensis mcculloch 1977 dorsal view, late pliocene, kafr el sheikh, sample from 1960 m, naf-2 well 25–26 valvulineria complanata, (d’orbigny 1846), 25. dorsal view, pleistocene-recent, baltim, sample from 1550 m, naf-3 well. 26. ventral view, pliocene, kafr el sheikh, sample from 1640 m, naf-3 well. 27 neoeponides sp.ventral view, pliocene, kafr el sheikh, sample from 1680m, naf-101 well. geologia croatica 63/1geologia croatica 20 ismail et al.: subsurface stratigraphy and micropaleontology of the neogene rocks, nile delta, egypt geologia croatica 21 ammonia perlucida (heron allan & earland), 1913 (pl. 4, fig. 23–24) 1913. rotalia perlucida heron allan & earland, p. 139, pl. 13, fi gs. 7–9 1990. ammonia perlucida (heron allan & earland)abu el enein, pl. 13, fi g. 8 ammonia tepida (cushman, 1926) (pl. 4, figs. 25–26) 1999 ammonia tepida (cushman)-abul-nasr & sala ma, p. 130, fi g. 19 (29) ammonia umbonata (leroy, 1944) (pl. 4, figs. 27–28) 1944 rotalia umbonata leroy, p. 35, pl. 7, fi g. 16–18 1980 ammonia umbonata leroy-billman et al., p. 87, pls. 6–8 elphidium macellum (fichtel & moll), 1798 (pl. 4, fig. 29) 1798. nautilus macellus fichtel & moll, p. 66, pl. 10, fi gs. e–k 1990. elphidium macellum (fichtel & moll)-abu el enein, pl. 13, fi g. 9 nonionina scapha (fichtel & moll, 1798) (pl. 4, fig. 30) 1798. nautilus scapha fichtel & moll, p. 105, pl. xix, fi gs. d–f plate 4 bar scale = 100 µm 1 neoeponides sp. dorsal view, middle miocene, sidi salim, sample from 3300 m, naf-3 well. 2 cibicidoides sp., early pliocene, kafr e sheikh, sample from 2625 m, naf-2 well. 3 eponidella cf. libertadensis cushman & hedberg, 1935 ventral view, pleistocene-recent, baltim, sample from 1550 m, naf-3 well. 4–5 asterigerina planorbis, d’orbigny 1846, 4. ventral view, pliocene, kafr el sheikh, sample from 1640 m, naf-3 well. 5. dorsal view, pliocene, kafr el sheikh, sample from 1640 m, naf-3 well. 6–7 nonionellina labradorica (dawson, 1860) 6. lateral view, pliocene, kafr el sheikh, sample from 1980 m, naf-101 well. 7. side view, pliocene, kafr el sheikh, sample from 1980 m, naf-101 well. 8–9 melonis pompiliodes, (fichtel & moll 1798) 8. lateral view, late pliocene, el wastani, sample from 1540 m, naf-101 well. 9. side view, late pliocene, el wastani, sample from 1540 m, naf-101 well. 10–11 pullenia osloensis, feyling & hassan 1954, 10. lateral view, late pliocene, el wastani, sample from 1540 m, naf-101 well. 11. side view, late pliocene, el wastani, sample from 1540 m, naf-101 well. 12 pullenia quinqueloba, (reuss 1851), middle miocene, sidi salim, sample from 3300 m, naf-3 well. 13 alabamina sp. ventral view, pliocene, kafr el sheikh, sample from 1640 m, naf-3 well. 14–15 gyrodinoides soldanii, (d’orbigny 1825), 14. ventral view, pliocene, kafr el sheikh, sample from 1680 m, naf-101 well. 15. side view, pliocene, kafr el sheikh, sample from 1680 m, naf-101 well. 16 buccella sp. dorsal view, pliocene, kafr el sheikh, sample from 1640m, naf-3 well. 17–20 ammonia beccarii, linne 1758, 17. lateral view, pleistocene-recent, baltim, sample from 1320 m, naf-3 well. 18. ventral view, pliocene, kafr el sheikh, sample from 2080 m, naf-101 well. 19. side view, pliocene, kafr el sheikh, sample from 2080 m, naf-101 well. 20. dorsal view, pliocene, kafr el sheikh, sample from 2080 m, naf-101 well. 21–22 ammonia ikebei, (inoue & nakaseko 1951), 21. ventral view, pleistocene-recent, baltim, sample from 1460 m, naf-3 well. 22. dorsal view, pleistocene-recent, baltim, sample from 1460 m, naf-3 well. 23–24 ammonia perlucida, (heron allan & earland 1913), 23. ventral view, pleistocene-recent, baltim, sample from 1460 m, naf-3 well. 24. ventral view, pleistocene-recent, baltim, sample from 1460 m, naf-3 well. 25–26 ammonia tepida, (cushman 1926), 25. ventral view, pliocene, kafr el sheikh, sample from 1980 m, naf-101 well. 26. dorsal view, pliocene, kafr el sheikh, sample from 1980 m, naf-101 well. 27–28 ammonia umbonata (leroy, 1944) 27. ventral view, late pliocene, el wastani, sample from 1540 m, naf-101 well. 28. dorsal view, sample from 1320m, naf-3 well, baltim, pleistocene-recent. 29 elphidium macellum, (fichtel & moll 1798, pliocene, kafr el sheikh, sample from 1460 m, naf-3 well. 30 nonionina scapha, (fichtel & moll 1798), early miocene, qantara, sample from 3530 m, naf-101 well. geologia croatica 63/1geologia croatica 22 1884. nonionina scapha (fichtel & moll)-brady, p. 730, pl. ix, fi g. 14–16 1930 nonionina scapha (fichtel & moll)-macfady en, p. 105, pl. iv, fi g. 17 6. environmental implications the environmental conditions of the neogene rocks of the studied wells are interpreted by using the results of some palaeoecological parametres (e. g. the total number of foraminifera (t.n.f.) and planktonic/benthic ratio (p/b). the fi rst parameter (t.n.f) is the number of foraminiferal individuals in one gram of dry sediments. it increases with increasing water depth as mentioned by bandy & arnal (1960). the planktonic/benthic ratio represents the number of planktonic foraminiferal individuals divided by the number of benthic foraminifera. it is low in near shore marine environment and increases with depth until the carbonate compensation depth (ccd) of approximately 4000 m is reached, below which only agglutinated foraminifera are found (pheleger, 1960). these parametres are graphically represented to refl ect the vertical distribution of the foraminiferal fauna of the different rock units (figs. 13, 14 and 15). the environmental conditions for each recognized rock unit are mentioned below based on these aforementioned parameters. the qantara formation was only represented in the naf101 well. it underlies the sidi salim formation. the facies of this formation is of non-marine clastics deposited by river currents and associated marginal marine transport processes, in a high-energy outer shelf environment. moreover, towards the north, the environment changed to a shallow marine one where clastics and even carbonates were deposited by wave transport processes in a relatively quieter inner shelf environment. this is shown by the relatively higher values of t.n.f. and high p/b values indicating an increase in water depth as shown on fig. 15. also, the occurrence of bolivina dilatata, gyroidinoides soldanii, bulimina elongata and globocassidulina oblonga indicates an increase of water depth (murray, 1991) as in fig. 15. the sidi salim formation overlies the qantara formation and underlies the qawasim formation. the faunal distribution shows considered values of t.n.f., high p/b values fi gu re 13: the paleoecologic parametres of naf-2 well. ismail et al.: subsurface stratigraphy and micropaleontology of the neogene rocks, nile delta, egypt geologia croatica 23 especially in the upper part of the formation which indicate an increase in water depth. furthermore, the occurrence of bolivina hebes, bulimina elongata, uvigerina pygmoidea, gyroidinoides soldanii and lenticulina antipodum suggests a deep shelf environment (murray, 1991) at the upper part of the sidi salem formation. moreover, there is a decrease in these values up to the middle of this formation as shown on fig. 14. the facies of this formation, towards north and northwest directions, can be described as shallow marine clastics deposited primarily by wave transport processes in a relatively low-energy outer shelf environment. furthermore, it gradually changes into a high-energy deltaic environment, towards the south and southeast, which resulted in clastic deposits being deposited from several channels. the qawasim formation overlies the sidi salim formation and underlies the rosetta formation. the values of t.n.f. and p/b ratio are relatively low indicating a decrease in water depth during deposition of this formation. it was deposited in a high-energy deltaic environment, towards the south and southeast directions. the occurrence of ammonia beccarii in the qawasim formation in the naf-3 well suggests a near-shore environment (van der zwaan & jorissen, 1991). the rosetta formation overlies the qawasim formation and underlies the abu madi formation. this unit is extrem ely poor in foraminifera. it refl ects a decrease in water depth during its deposition. deposition of evaporites in this formati on indicates a general regression of the whole mediterranean. the top of this formation coincides with a general regression of sea level all over the study area, which is contemporaneous with the "messinian salinity crisis" phenomenon all over the mediterranean hsu et al. (1973, 1977). the abu madi formation overlies the rosetta anhydrite and underlies the kafr el sheikh formation. the faunal distribution shows an increase of t.n.f. values and high p/b values indicating an increase in water depth during deposifi gu re 14: the paleoecologic parametres of naf-3 well. geologia croatica 63/1geologia croatica 24 tion of this formation (fig. 13). the occurrence of bolivina hebes (as in naf-3 well) refl ects a neritic type of bolivines (douglas, 1979). furthermore, the occurrence of the costate uvigerina semiornata (as in the naf-3 well) that prefers anoxic conditions and fi ne-grained substrate (boersma, 1984) suggests a shallow environment. the kafr el sheikh formation overlies the abu madi formation and underlies the el wastani formation. the faunal distribution refl ects an increase of t.n.f. values and high p/b values mostly at the top and the base of this formation, if compared to the middle part, indicating a fl uctuating water depth which is lower for the central section of the formation. the occurrence of cassidulina brocha, ammonia beccarii, a. tepida, pullenia osloensis, bolivina dilatata, bulimina elongata, uvigerina pygmoidea and vulvulineria complanata suggests a higher water depth in the lower part of the kafr el sheikh formation. also, the same conditions prevailed in the upper part of the same formation as indicated fi gu re 15: the paleoecologic parametres of naf-101 well. ismail et al.: subsurface stratigraphy and micropaleontology of the neogene rocks, nile delta, egypt geologia croatica 25 by the occurrence of elphidium advenum, quinqueloculina bosciana, globocassidulina oblonga and fursenkoina schreibersiana. the el wastani formation overlies the kafr el sheikh formation and underlies the baltim formation. the faunal distribution of this formation refl ects an increase of t.n.f. but low p/b values. this represents a lowering of the water depth during deposition of this formation as shown on fig. 14. the top of this formation coincides with a regression of sea level all over the study area. also, the occurrence of ammonia-elphidium and valvulineria-fursenkoina assemblages suggests a near shallow environment and a decrease in water depth through the el wastani formation. the baltim formation overlies the el wastani formation and underlies the mit ghamr formation. the faunal distribution of this formation is only observed for the lower part (fig. 14) due to a lack of samples. the facies in the southern parts, of the study area, can be described as shallow marine. intercalations of sand, shales and even carbonates were deposited, primarily by wave transport processes, in a high energetic outer shelf environment which become more quiet towards the north. the mit ghamr formation overlies the baltim formation and underlies the bilqas formation. the facies can be described as clastics and even carbonates deposited in a quiet shelf environment, where these sediments were affected by postdepositional processes forming some sort of canyon in the older sediments. finally, the bilqas formation covers the whole delta. azzam (1994) mentioned that during this time, the marine transgression covered most of the northern delta area and gave rise to a few metres of marine sediments capped by agricultural soil. this is repetition whereas this section is about the faunal content and depositional environment, where no samples are available in this interval. 7. conclusion the present work deals with the stratigraphy and micropaleontology of the sedimentary sequence in the north abu qir field, nile delta, egypt. three wells (naf-2, naf-3 and naf101) were described, sampled and micropalaeontologically investigated. the lithostratigraphic studies have been carried out on the study area helped in the recognition of the miocene–pliocene rock units of the study area. these units are (from base to top) the qantara formation, sidi salim formation, qawasim formation, rosetta formation, abu madi formation, kafr el sheikh formation, baltim formation, mit ghamr formation, and bilqas formation. the qantara formation is dated as early miocene according to the presence of globigerinoides primordius. this age assignment is confi rmed by the presence of the early miocene forms such as globoquadrina altispira altispira and globorotalia obesa (kennett & srinivasan, 1983). the sidi salim formation is of middle miocene age due to the presence of globigerinoides bollii, at the top of this formation, which could represent a useful datum in the mediterranean, where the globorotalia fohsi lineage is not developed (bolli & saunders, 1985). on the other hand, the absence of the three upper biozones of the middle miocene (globigerinoides ruber, globorotalia mayeri and globorotalia menardii biozones) indicates a hiatus between the middle and late miocene. however, the presence of praeorbulina glomerosa curva and praeorbulina glomerosa glomerosa species supports an early middle miocene age for this formation, which is directly overlain by the upper miocene sediments. this indicates a hiatus between the early middle and late miocene. accordingly, this formation is dated as being from the early middle to late miocene. the qawasim formation is dated to the late miocene according to its stratigraphic position between the underlying sidi salim formation of early middle miocene to late miocene age and the overlying rosetta formation of late miocene. this rosetta formation is of late miocene (messinian) age, due to its stratigraphic position below the well-defi ned early pliocene marine sediments, together with, the presence of the defi nitive sphaeroidinellopsis disjuncta in the topmost part of this formation. references abu el enein, m.a. (1990): contribution to the miocene stratigraphy of the nile delta. ph.d. thesis, geology department, faculty of science, ein shams university, cairo, egypt, 186 p. azzam, a.s. (1994): an integrated seismo-facies and seismo-tectonic study of the nile delta of egypt, utilizing common-depth seismic refl ection data. ph.d. thesis, geology department, faculty of science, ein shams university, cairo, egypt, 240 p. badran, a.m. (1996): the contribution of logging analysis and seismic stratigraphy in the reservoir valuation and lithology determination of the north western delta abu qir offshore egypt. ms.c. thesis, geophysics department, faculty of science, ein shams university, cairo, egypt, 112 p. barakat, m.g. (1982): general review of the petroliferous provinces of egypt with special emphasis on their geological setting and oil potentialities. geology department, faculty of science, cairo university, cairo, egypt, 87 p. boersma, a. (1984): handbook of common tertiary uvigerina. – microclimates press, n.y., 207 p. bolli, h.m. & saunders, j.b. (1985): oligocene to holocene low latitude planktic foraminifera.– in: bolli, h.m., saunders, j.b. & perch-nielsen, k. (eds.): plankton stratigraphy. cambrid ge earth science series, cambridge university press, 155–262. cita, m. b. (1975): the miocene/pliocene boundary: history and defi nition. micropaleontology, special publication, 1, 1–30. deibis, s., futyan, a.r.t., ince, d.m., morley, r.j., seymour, w.p., thmpson, s. (1986): the stratigraphy framework of the nile delta and its implications with respect to the region’s hydrocarbon potential. egpc, eighth exploration conference centenary of fi rst oil well, nov. 7–23, 15 p. douglas, r.g. (1979): benthic foraminiferal ecology: a review of concepts and methods.– in: lipps, j.h. et al. (eds.): foraminiferal paleoecology. sepm short course, 6, 21–53. e.g.p.c. (1994): nile delta and north sinai. fields, discoveries and hydrocarbon potentials. cairo, egypt. effat, a. & el gezeiry, m. (1986): new aspects for abu qir stratigraphic and sedimentologic model. wepco, p.o. box 412, alex., egypt. geologia croatica 63/1geologia croatica 26 hsu¨, k.j., ryan, w.b.f. & cita, m.b. (1973): late miocene desiccation of the mediterranean.– nature, 242, 240–244. hsu¨, k.j., montadert, l., bernoulli, d., cita, m.b., erickson, a., garrison, r.e., kidd, r.b., melieres, f., muller, c. & wright, r. (1977): history of the mediterranean salinity crisis.– nature, 267, 399–403. ismail, a.a. (1984): quantitative well logging analysis on some subsurface successions in the nile delta area. ms.c. thesis, geology department, faculty of science, ain shams university, cairo, egypt, 214 p. kennett, p. & srinivasan, m.s. (1983): neogene planktonic foraminifera a phylogenetic atlas. university of rhode island, distributed worldwide by van nostrand reinhold company inc., 135w. 50th street, new york, n y 10020, 265 p. macfadyen, w.a. (1930): miocene foraminifera from the clysmic area of egypt and sinai.– geol. surv., egypt, 1–149. murray, j.w. (1991): ecology and paleoecology of benthonic foraminifera.– longman scientifi c and technical, england, 397 p. rizzini vessani, f., cococetta, v. & milad, g. (1978): stratigraphy and sedimentation of neogene-quaternary section in the nile delta area.– marine geol., 27, 327–348. said, r. (1990): the geology of egypt, egpc, conco, hurghada inc. and repsol expl. s.a., 743 p. said, r. (1975): the geological evaluation of the river nile.– in: the prehistory of the middle east and the levant. south methodist univ. press, 7–44. schlumberger (1984): well evaluation conference, egypt, geology of egypt, 1, 1–64. souaya, f.j. (1966): miocene foraminifera of the gulf of suez region, u.a.r. micropaleontology, january, 1966, 12/1, 34–64, pls. 1–4. van der zwaan, g.j. & jorissen, f.j. (1991): biofacial pattern in river-induced shelf anoxia. – in: tayson, r.v. & pearson, t.h., (eds.): modern and ancient continental shelf anoxia. geol. soc. spec. publ., 58, 65–82. manuscript received april 27, 2009 revised manuscript accepted november 10, 2009 available online february 28, 2010 07-faivre.indd 67 �ab stra ct the rainfall event during the night of 10th–11th september 2007 caused strong erosion in the gully of potovošća on the island of krk. in the main fan, two new gullies and two fans were formed. those morphological changes have been mapped, measured and explained, across the drainage basin in terms of topography and precipitation intensity. the drainage basin morphology was studied using gis that allowed comparison of morphological and dynamic relationships within the study area. in order to obtain the relative potential erosion intensity between different points in the basin, as well as to differentiate areas with areal (diffuse) erosion from those with dominant linear erosion, the stream power index (spi) was calculated. the drainage basin specifi c properties were further related to the event specifi c properties, precipitation intensity and hydrologic estimations. the rainfall intensities obtained, allow the calculation of discharge at the gully mouth and the defi nition of recurrent periods using the rational method. the rainfall-runoff event studied was also infl uenced by the relatively high antecedent precipitation index (api). this allows explanation of the morphological consequences of the short-term event. consequently the interrelationship between short-term and long-term events has been discussed. in addition, the physiography of the gully has been recently modifi ed by human interference, which has also infl uenced the morphological consequences of the aforementioned short-term rainfall event. keywords: gully erosion, precipitation intensity, rainfall-runoff relationship, beach dynamics, krk island, croatia the gully of potovošća on the island of krk – the eff ects of a short-term rainfall event � sanja faivre1, mladen pahernik2 and mladen maradin1 1department of geography, faculty of science, university of zagreb, marulićev trg 19/ii, 10000 zagreb, croatia, (sfaivre@geog.pmf.hr) 2croatian defence academy, ilica 256 b, 10000 zagreb, croatia doi: 104154/gc.2011.07 geologia croatica 64/1 67–80 8 figs. 6 tabs. zagreb 2011 geologia croaticageologia croatica 1. introduction the shorelines of the island of krk are primarily rocky. rocky coasts are predominantly erosional forms, while unconsolidated and poorly consolidated sediments like beaches are primarily depositional in nature, these being present to a much lesser extent. a beach is an accumulation on the shore of generally loose, unconsolidated sediment, ranging in size from very fi ne sand up to pebbles, cobbles and occasionally boulders (bird, 2008). most of the beaches on the island of krk, as well as those along the whole adriatic coast, are formed of sediments, which range between sand and pebble and, rarely, cobble in size. the majority of the beaches along the croatian coast are formed from proluvial fan material of the drowned torrent karstic valleys similar to the gully of potovošća (fig. 1). occasional fl ows bring pebbles and cobbles and form fans, in which gravely beaches formed in contact with the sea. therefore, as is usual in temperate zones, the beach material is primarily composed of sediments of terrigenous origin (pirazzoli, 1993). these are sands and pebbles that come from the hard fl uvial drift (alluvium), or from the destruction of headlands. in the areas of less resistant rocky coasts, wave-cut notches are formed and cliffs evolve. the pebble beaches at the foot of the cliffs are relatively narrow, due to the quite short (less than 6 000 years) period of wave action on the coast. such an example can be geologia croatica 64/1geologia croatica 68 found near the studied area, the beach and the pod črnice cliff (fig. 1) which is still an active cliff, 132 m long, with notches at its foot, and a beach up to 10 m wide (faivre, unpublished). the gully of potovošća is 4.2 km long with a catchment area of 3.3 km2. it is formed in the upper cretaceous limestone, mainly reef and foraminiferal limestone (according to šušnjar et al., 1970) (fig. 2). this gully is episodically active, but some of the nearby gullies also lose their hydrological function. this can be observed in the bay of kozica, near vrbnik (fig. 1), which is largely fi lled today with a thick cover of colluvial sediments (> 2 m), (faivre, unpublished). this study of the gully of potovošća, is part of a larger work examining several gullies and beaches in this region, including the aforementioned pod črnice cliff and kozica gully, together with the gully in vrbnik (luka vrbnik), the gully of prva draga near senj and uboka near mošćenička draga (fig. 1). the primary aim was to identify gullies with beaches showing different patterns of evolution. the relationship between the recent morphology of these torrent valleys, morphology of the bays and present sea level indicates that the valleys and gullies had been formed earlier, when sea level was lower. the dynamic geomorphology of the kvarner area coastline is regulated by interrelated changes in sea level, erosion and deposition of sediments along the coastal margins (juračić et al., 1999; surić & juračić, 2010). under postglacial conditions or rapidly rising sea levels, the dominant geomorphic process shifts from erosion to deposition, with fi ner sediments deposited in bays or estuaries formed at the mouths of newly fl ooded coastal canyons rather than along the coastline. as sea-level rise slows, these estuarine and gully embayments fi ll with sediments (benac et al., 1991; faivre et al., 2011). following this culmination of sea-level rise, new bays were formed and actual beaches shaped in proluvial fans. in such a way numerous pocket-beaches have been formed along the eastern rocky coast of the island of krk. the dynamics of pocket beaches has not been studied to the same extent as the open sandy beaches. there are very few papers dealing with this kind of subject (e.g. storlazzi & field, 2000), particularly those related to the kvarner area (e.g. benac, 1996; juračić et al., 2009; benac et al., 2010). gullies on the island of krk have been studied by benac (1992) explaining that most of them are not active any more, meaning there is no fl ow even in periods of intensive rainfall. their bottoms are covered with humus and redeposited clay and are overgrown with vegetation. according to benac (1992) this is a clear indicator of relief energy decrease as a consequence of holocene sea level rise. the latest paper of benac et al. (2010) deals precisely with the morphodynamics of the kvarner area pocket beaches. observing the changes in beach morphology after a heavy rainfall event in the fi eld, we try to examine this short event, as best as possible, studying morphometric relief parameters, climatic elements from the nearest stations and their morphological consequences. the aim is to determine how the pocket beaches react to such short-term events and to estimate climatologic and hydrological properties which can produce the changes observed. the new opened profi le in the beach allows questions to be raised on the longer term evolution of the beach. sedimentary features such as beaches are perceived as having high social and economic value today. therefore, human impact is more and more accentuated along the croatian coast. the beach of potovošća has just started to come under fi gu re 1: study area with several other beaches mentioned in the text (1-pod črnice; 2-kozica; 3-luka vrbnik; 4-uboka; 5-prva draga). faivre et al.: the gully of potovošća on the island of krk – the eff ects of a short-term rainfall event geologia croatica 69 the fi rst direct human impact. since 2006, the beach has been under concession and it is artifi cially levelled for tourism purposes every year in july. consequently, we must take not only natural but also anthropogenic factors into account in this study. 2. materials and methods the fi rst fi eld investigation started a week after the event. all the morphological changes were mapped and measured using gps garmin etrex vista hcx. the results have been presented on the main croatian map 1: 5000 from the state geodetic survey. the precise longitudinal profi le across the fan of the gully was made using a suunto clinometer, calculating inclinations at 20 points. the part submerged by the sea has also been mapped and measured, corrected for tide, pressure and wind. the coastline has been mapped several times since 2007. further study of this event has been undertaken through the analysis of the drainage basin specifi c properties and event specifi c properties. the drainage basin properties were analysed using gis, whereby, the digital relief model was interpolated on the basis of altitudinal data, digitalized contour lines, elevation points and breaklines of slope from the topographical map on the scale of 1: 25000 (e=10 m). the tin relief model of the investigated area was generated from these data, and later transformed into a raster grid structure with 10 ́ 10 m cells. the calculated digital relief model was the basis for the digital geomorphologic analyses of the drainage basin parameters. for these analyses and visualization of the obtained results, the arcgis version 9.3 programme package was used, including spatial analyst and 3d analyst extensions. morphometric characteristics of the drainage basin, that is, hypsometrical properties, the distribution, shape and the angle of slopes as well as the distribution and orientation of the ridges and valleys represent the basis for the analysis of derasion and erosion intensity. the calculation of quantitative indicators of dynamical geomorphologic processes inside the river basin, primarily using the digital relief model, is the basis for numerous methods inside the digital relief analyses (gallant & wilson, 2000). as an indicator of the potential erosion intensity inside the whole investigated area, the values of the stream power index were calculated at particular points of the drainage basin. the stream power index is calculated according to the equation (moore et al., 1991): spi = ln(as ´ tanβ), where as (m2/m) – is the specifi c catchment (catchment area draining across a unit width of contour), and β(°) – the slope angle in the studied point (cell of the grid). to analyse the event specifi c properties different methods have been used. precipitation intensity was calculated in order to establish the volume of precipitation that falls on the studied area. the precipitation intensity is defi ned as the precipitation volume that falls over a particular area in a defi ned time-period (šegota & filipčić, 1996). as it is recommended to observe only periods with registered precipitation, precipitation intensity was calculated as a quotient of the precipitation volume and of the number of days with precipitation. as there are no precipitation data for the researched location, the data from the nearest stations were used. those are: the meteorological stations at crikvenica, senj, omišalj (airport), malinska and krk (fig. 1). in order to get a better overview of precipitation intensity at the stations mentioned, the precipitation amount was analysed for the 1981−2007 period. since no continuous data-series exist for the meteoro logical stations of malinska and krk, shorter time series were analysed. with the aim of analysing precipitation amount on 11th september and its relationship to average precipitation, standard deviation is calculated. according to confi gu re 2: lithological map of the studied area, (šušnjar et al., 1970). legend: 1-quaternary sediments, 2-limestone breccias, 3-foraminiferal limestone, 4reef limestone, 5-dolomites with limestone fragments. geologia croatica 64/1geologia croatica 70 rad & pollak (1950), the following are the groupings and nomenclature of precipitation deviation from averages: above +3 σ extremely above normal between +2 σ and +3 σ greatly above normal between +σ and +2 σ above normal between + σ and – σ normal between –2σ and – σ subnormal. the inverse distance weighted (idw) interpolation method (power 3.5) has been used to defi ne the precipitation intensity for the studied area, with root mean square error (rmse) = 38.7. this method was chosen because the calculated error was the smallest. the inverse distance weighted interpolation determines cell values using a linearly weighted combination of a set of sample points. the weight is a function of inverse distance. the power option of idw lets us control the signifi cance of known points on the interpolated values, based on their distance from the output point. it is a positive, real number. furthermore, there are several other methods that could be used for precipitation analyses which can give more precise insights into the rainfall-runoff relationship in small drainage basins, like the potovošća one. one of these is short-term precipitation analysis. in the research area and its surroundings, short-term precipitation is only continuously measured at the senj and rab meteorological stations, while on the omišalj airport station the data are not continuous and could not be obtained from the meteorological and hydrological service in zagreb. consequently due to the lack of data, it was not possible to conduct precise analyses of shortterm heavy rainfalls. as an alternative to short-term rainfall analyses the analyses of annual maximum daily precipitation are mostly used for small drainage basins (rubinić et al., 1995; gajićčapka & čapka, 1997; gajić-čapka, 2002). analysis of annual maximum daily precipitation, using some of parameters methods, could be conducted if long-term data series are available. gajić-čapka (1999) showed that in the croatian littoral the series of annual daily maximum precipitation values stabilizes during the time span of 80 years, consequently long-term data series are required. they are needed for short-term heavy rainfall analyses as well. rubinić (2003) suggests usage of data series of at least 50−60 years. since the available data series are far too short for all the meteorological stations on krk island (less than 30 years), the parameters methods couldn’t be undertaken, to meet the requirements of this paper. therefore, the results of rubinić (2006) were used, which provide an estimate of short-term heavy rainfall in the broader regional context that also allows us to give some hydrological estimation. for the calculation of peak discharge (maximal stream fl ow) in the potovošća drainage basin, the rational method was used. this is a simple technique for estimating a discharge from a small watershed. it was developed by mulvaney (1851) and further advanced by kuichling (1889) for drainage basins in urban areas. the method is described in many textbooks (e.g. žugaj, 2000). it is based on a formula that relates the runoff-producing potential of the watershed, to the average intensity of rainfall for a particular length of time (the time of concentration), and the watershed drainage area. the formula is q = c * i * a * cu, where: q – maximal fl ow (peak) [m3/s] c – rational (runoff) coeffi cient i – rainfall intensity [mm/s] a – surface of the drainage basin [km2] cu – units conversion coeffi cient (1000) the rainfall or storm intensity, i, is a function of geographic location and design exceedence frequency or return interval. consequently, the longer the return interval it is the greater the precipitation intensity for a given storm duration. furthermore, the longer the length of the storm, the lower the storm average precipitation intensity (thompson, 2006). the relationship between these three components, storm duration, storm intensity and storm return interval is represented by curves called intensity-duration-frequency curves (idf curves). the climatological data for the creation of idf curves of defi ned recurrent periods have been used from rubinić (2006) who calculated maximal short-term heavy rainfalls (mm) inside the defi ned periods (24h; 12h; 6h; 2h; 1h; 40’; 30’; 20’ and 10’) according to the recurrent periods (1.25; 2; 5; 10; 20; 50; 100 years) for the punat area. as there is no available adequate data for krk island area at all, rubinić (2006) used data from the nearby stations of pula, rijeka and senj obtaining data of larger regional signifi cance. in this paper the rainfall intensity was calculated using the following formula: i = h/to where: i – rainfall intensity (mm/s) h – rainfall amount (mm) to – length of the rainfall (period, interval) (min), that is, the idf curves have been obtained for defi ned recurrent periods. as the rainfall intensity (i) is a function of the concentration time tc and the recurrent period p, where i = f (tc, p) the time of concentration tc have been calculated to select the average rainfall intensity from idf curve. the time of concentration, tc, of a watershed is the time required for runoff to travel from the hydraulically most distant point to the outlet of a watershed (kirpich, 1940; mccuen et al., 1984). tc is a time parameter widely used to estimate peak discharges in hydrologic designs. the concept of tc is useful for describing the time response of a watershed to watershed runoff, that is at tc the watershed is fully contributing. if the chosen storm duration is larger than tc then the rainfall intensity will be less than that of tc. therefore, the peak discharge estimated using the rational method will be less than the optimal value. if the chosen storm duration is less than tc, then the watershed is not fully contributing to runoff to the outlet for the storm length, and the optimal value will not be realised, therefore it is defi ned that the storm length is equal to tc for use in estimating peak discharge using the rational method. as it is very small drainage faivre et al.: the gully of potovošća on the island of krk – the eff ects of a short-term rainfall event geologia croatica 71 basin, the kirpich (1940) formula has been used for calculation of the time of concentration of the potovošća drainage basin as follows: tc [hours] = 0.00032*l0.77*imax –0.385, where: l – maximal length of the travel of water [m] imax – down drop of the drainage basin (δh/lmax). according to the standard tables (žugaj, 2000) for steep slopes, the runoff coeffi cient c was defi ned as c = 0.3. from the obtained parameters, the maximal stream fl ow, that is the peak discharge, q (qpeak mm/s) for the potovošća drainage basin according to defi ned recurrent periods has been calculated. for the calculation of short-term rainfall intensity for the night of 10th–11th september 2007, only the hourly rainfall time series for senj and rab meteorological stations have been obtained, and according to which the discharge during the studied event has been estimated. as the soil moisture condition prior to a rainfall event has a great infl uence on runoff generation process, higher moisture content, generally, leads to a higher runoff generation (chow, 1988; descroix et al., 2002) and vice versa. hence, the antecedent precipitation index (api) [mm] is often used as a measure of soil moisture condition. it is based on the assumption that soil moisture after a rainfall event decreases exponentially (patil, 2008). the more time elapsed after rainfall has ceased the less moisture remains in the soil due to evaporation and infi ltration losses. so, the api has been calculated using the following equation: ( ) ( )api t p t0 1 i i dly n 0 1 λ= = -/ where: pdly – daily rainfall λ – decay factor the decay factor λ normally ranges between 0.85 and 0.98 (heggen, 2001), depending on the catchment of the region, but most of the empirical investigations suggest λ=0.90 (patil, 2008). therefore this value was used in the study. in api usage, i, is typically 5, 7, or 14 days (heggen, 2001). in this study api time series have been calculated with 7 antecedent days (n=7 days). 3. results 3.1. morphological consequences of the shortterm event after a long period of dry weather a strong storm with very intensive rainfall occurred during the night of 10th−11th september 2007. the gully became active and the beach responded almost instantaneously to the high volume of water fl ow. during the storm, two incised gullies were formed in the beach (figs. 3 & 4a). the western one, 18 m long, does not have any visible torrent bed in the background today, while the eastern gully is a continuation of the main gully system. during the storm, water also came from fresh water sources located longitudinally to the beach near the dry walls. two new fans, around 8 m long, were formed in the sea (fig. 4a) mainly from beach sediments. they are positioned on the edges of the previous, older and larger fan (fig. 3). the gullies in the beach were 7 and 9 m wide, respectively, at the mouth. both of them were incised 80 cm into the beach sediments (fig. 3). according to the morphology of the new gullies, the volume of the eroded beach sediments was calculated as ∼130 m3±10%; 58 m3 for the eastern and 72 m3 for the western gully. the accuracy of the calculated volume is limited because of the relatively small number of measured points. the layers of different size beach sediments are easily observed on the profi les of the gullies. in the profi le of the eastern gully, a succession of organic layers is observed, indicating the periodic torrential episodes. in the western profi le, a layer of boulders is observed 60 cm below the upper beach surface. their position and size point to the ancient torrent valley (figs. 3 & 5). these relationships could also be related to a lower sea level of that period, as well as to the landward migration of the beach profi le. the same storm had much less visible impact on the hard rocky coast, but while changes to rocky coasts are long-lasting to permanent, beaches may quickly recover from storms. most beaches are susceptible to raid morphological changes. their topography and volume vary with wave-climatic refi gu re 3: the ground plan of the potovošća bay with eff ects of the shortterm event, with longitudinal (a-b) and transversal profi les (c-d; e-f). legend: 1-dray wall, 2-gully bed. 3-ground-plan of the main proluvial fan below the sea, 4-gully formed during the rainfall event, 5-proluvial fan formed during the rainfall event, 6-profi le across the main proluvial fan, 7-gully cross section. geologia croatica 64/1geologia croatica 72 gimes (dubois, 1988), which generally coincide with the winter and summer seasons. a very good example of a beach which responds to seasonal variations in the kvarner area can be observed in the bay of uboka, (faivre, unpublished). rapid changes of the potovošća beach occur particularly in stormy weather. after the storm, a strong ne bora wind blew at potovošća, with waves starting to reshape it immediately. the waves created a 60 cm high beach berm near the shoreline, behind which two small temporary ponds were created. these short repeating episodes can be observed on the eastern gully in the profi le marked by organic material. the ponds were 3 m from the sea. the existence of lateral channels in the gully indicates the large volume of water fl owing in a very short time. therefore, we tried to establish rainfall intensity and the rainfall-runoff relationship that produces such incised gullies in unconsolidated sediments, displacing 130 m3±10% of beach sediments, as well as to defi ne the morphological characteristics of the drainage basin as a whole. as the surface was artifi cially levelled 2 months before the event, it was almost like a laboratory simulation experiment. in fig. 4b, the naturally reshaped beach, is observed six months after the event. the beach tends again toward its equilibrium state. the width and inclination of the beach is a function of the available amount of material, wave energy and strength of the currents that can transport this material. the waves sort the beach material and give a characteristic shape to the beach. the biggest pebbles or boulders are accumulated at the top of the beach, which moves only during extremely high sea-level events (during storms). the fi ner material is located at the seaward end of the beach. therefore, the beaches are often sandy in contact with the sea. on potovošća beach, the surface anthropogenic impact disables the study of surface sediment distribution but, fortunately, deeper layers are undisturbed. the potovošća beach is embayed and 121 m long. under natural conditions it was up to 10 m wide. it is a low-tide beach with an average daily sea-level range of 48 cm (archive of the geophysical department, faculty of science, zagreb; for 1930−2009). at the beginning of june 2008, before the beach was artifi cially levelled, a profi le along the main fan was made (fig. 3). the profi le is 64 m long: 37 m on the shore and 27 m below sea level. it represents a punctual stage of the beach morphology. as can be observed, the beach has a gentle profi le. the inclination varies between +0.5° in the back area, behind the beach berm, up to −14°, which is attained at contact of the beach with the sea, at the time of measurement. generally, the beach profi le does not show great seasonal variation. the submerged part of the fan shows granulometric regularity, from coarse sand to large boulders at the end of the fan, 4 m below msl. the contact can be seen in fig. 3. the potovošća beach can be regarded as a relatively closed system where sedimentary exchanges are minimal. even if embayed beaches have received more focused research, since they have been recognized as being morphologically distinct from open coasts (stephenson & brander, 2003), there is still a lot of work to do in order to better understand their functions. fi gu re 4: a) the beach of potovošća after the short-term event (22.09.2007), b) the beach outlook six month after the short-term event (14.03.2008). fi gu re 5: profile along the western gully formed after the storm (22.09.2007). a) b) faivre et al.: the gully of potovošća on the island of krk – the eff ects of a short-term rainfall event geologia croatica 73 3.2. drainage basin specifi c properties drainage basin specifi c properties are dependent on the particular location and include morphological properties, size, shape, and slope of the catchment, spi, time of concentration, land use and vegetation. on the basis of the hypsometrical characteristics of the area and longitudinal profi le of the gully, the basic morphological characteristics of the investigated area can be observed (fig. 6). the drainage basin area includes the north-eastern edge of the larger karst plateau which is, in this section, inclined in a north-south direction. the hlam elevation is located in the upper part of the basin, on its south-western edge, this being separated from the aforementioned plateau by the source part of the main gully. the lower part of the basin is characterized by an angle of 10° with a better developed system of gullies which are, on average, 1.8 km long. the main gully of the drainage basin is oriented southwest-northeast and is 4.2 km long (fig. 6). a largegreat part of the drainage basin, 45.5%, belongs to the slope inclination class of 12−32° in which gullying processes usually take place. on the whole, 80.9% of the basin is included in two inclination classes, the aforementioned one, and that of 5−12° (fig.7). the gully system described is much better expressed on the map of the stream power index (fig. 7). the stream power index was chosen to estimate terrain erosive power as according to tagil & jenness (2008) it is indicative of the potential energy available to transport sediments. areas with high stream power indices have a great potential for erosion what allow the highlighting of areas with high potential for sediment removal and hence are prone to gullying (kakembo et al., 2009). higher values of the index (3.2– 5.4) are found in the upper part of the basin, on the slopes of the hlam elevation (m. hlam, 446 m) and the source part of the gully, while it increases again on the developed system fi gu re 6: the drainage basin of potvošća gully with longitudinal profi le. fi gu re 7: stream power index map with histogram of slopes for the potovošća drainage basin. geologia croatica 64/1geologia croatica 74 of the shorter gullies in the lower parts. generally, the maximum values of the stream power index inside the lower part of the basin are related to the linear spreading of the gullies, while in the upper part they are related to the areal slope distribution (fig. 7). the system of well developed gullies in the lower part of the basin with concentrated linear erosion potential enables powerful runoff and transport of the eroded material from the upper parts of the basin till its deposition. exposed morphological properties of the catchment directly infl uence the time of concentration tc, as one of the important parameters for the peak runoff estimation at the gully mouth, as well as for the estimation of runoff during the studied short-term event. the time of concentration has been calculated where: the length of the gully bad l= 4198 m and the total down drop of the gully bad imax= (calculated as δh [m]/l [m], real length) 385/4198 = 0.09. the obtained tc for the study area is 0.49 h, that is 29.7 min. as it is a relatively small-size catchment area the periodic fl uvial inputs do not importantly infl uence the sediment budget of the beach on the time scale of several hundred years due to the presence of a dry-walls system behind the beach, against which the sediments are banked up and recent vegetation recovering due to the change in land use after the world war ii. namely, the increase of infi ltration and evapotranspiration was followed by the decrease of erosion and gullying, meaning a smaller sediment supply to the beach. therefore, it is primarily precipitation intensity which infl uences changes of beach morphology during the rainfall event on the night of september 10−11th 2007. 3.3. event specifi c properties event specifi c properties are those which are dependent on the rainfall-runoff event and the conditions prior to the event. the main event specifi c properties include total rainfall, event duration, and season and antecedent moisture conditions. the selected meteorological stations in the study are characte rised by a similar average annual course of monthly precipitation since they are situated close to one another. the da ta about the average annual course of monthly precipitation intensity (table 1) show the infl uence of precipitation on erosion processes. the maximum precipitation intensity, for all stations except malinska, is in september, which is the refore the optimal period for strong erosional (gullying) pro cesses on the studied area. the precipitation intensity in july and august is, on average; two times lower than in september. the amount of rainfall that caused gullying processes during the night of september 10−11th 2007 was measured on september 11th, according to precipitation data methodology. the observed stations, apart from the krk station, had higher precipitation amounts on that day than the average of mean daily precipitation intensity in september (table 2). three meteorological stations (omišalj, senj and malinska) had precipitation volume extremely above normal, one (crikvenica) had greatly above normal, and one (krk) station had deviation of precipitation amount within one standard deviation, that is, normal precipitation amount. for the calculation of the interpolated values, daily precipitation volume at the 19 surrounding meteorological stations on september 11th 2007 has been used (table 3). according to the idw interpolation results (fig. 8) the potovošća area had 40 mm of precipitation on that day. as the precipitation intensity is particularly variable in space, and depends on numerous factors which are not taken into account, we assume that this is the minimum value, as the nearby stations malinska and senj had much larger amounts of precipitation on that day. therefore, it is highly likely that the volume was higher. besides the precipitation volume on the event day, precipitation during the antecedent days is also very important, because the soil moisture content of small catchment areas may strongly infl uence rainfall-runoff processes (kovář, 2004). according to the precipitation amount of the last 7 days before the heavy rainfall episode, that is, to the calculated api (table 3) the saturation of the soil with water could be roughly estimated as relatively high on the krk island, which additionally emphasizes the runoff effect in the drainage basin that day. the equation parameters of idf curves have been calculated based on the precipitation intensity actable 1: average annual course of monthly precipitation intensity (mm) for 1981–2007 period. meteorological station i ii iii iv v vi vii viii ix x xi xii year omišalj 8.5 9.8 9.7 7.3 8.6 8.3 7.6 11.3 14.4 13.6 11.8 10.4 10.2 senj 7.8 9.0 8.3 7.7 9.4 8.8 5.9 12.3 16.4 12.5 12.3 10.2 10.1 crkivenica 10.2 10.9 10.8 8.5 10.6 10.6 7.9 12.4 19.1 16.1 13.1 11.3 12.0 malinska * 10.5 10.6 11.5 9.5 9.7 8.6 8.4 12.7 17.2 17.5 14.0 12.2 12.2 krk** 12.0 12.8 11.4 10.9 12.3 8.4 7.3 12.1 19.2 16.7 13.8 12.6 12.9 *1992–2007 period **1999–2007 period table 2: daily precipitation on september 11th 2007 (mm), standard deviation and precipitation deviation from averages. meteorological station daily precipitation (mm) standard deviation of daily precipitation precipitation deviation from average omišalj 38.8 5.2 4 sd senj 81.3 8.2 7 sd crkivenica 36.2 10.2 2 sd malinska 72.0 10.8 4 sd krk 16.7 14.1 0 sd faivre et al.: the gully of potovošća on the island of krk – the eff ects of a short-term rainfall event geologia croatica 75 cording to recurrent periods (table 4). according to the idf curves for determined recurrent periods the rainfall intensity has been calculated for the obtained tc (table 5). from the coeffi cient c, defi ned as c=0.3 and the surface of the drainage basin which amounts a = 3347890 m2 the calculation of the peak discharge (maximal stream fl ow) for the potovošća drainage basin according to defi ned recurrent periods has been calculated (table 5). once the maximum peak discharge for the potovošća drainage basin was acquired for recurrent periods we aimed to calculate the discharge during the studied short-term heavy rainfall event, from the night of 10th to 11th september 2007. the aforementioned lack of short-term rainfall data for the krk island meteorological stations led us toward the available data for stations senj and rab. at rab station there was almost no rainfall recorded, therefore only the senj metetable 3: daily precipitation at the 19 surrounding meteorological stations on september 11th 2007, precipitation amount in august and 10, 5 and 3 days before the event (mm) with the antecedent precipitation index in mm for the nearby meteorological stations. meteorological station latitude longitude altitude (m a.s.l.) daily precipitation on 11.09.2007 (mm) precipitation in august 2007 (mm) 10 days before the event (mm) 5 days before the event (mm) 3 days before the event (m) api (mm) bakar 45°18’ 14°32’ 12 35.2 73.1 32.6 4.1 3.2 16.5 brinje 45°00’ 15°09’ 483 205.8 104.6 59.4 14.2 7.6 – cres 44°57’ 14°25’ 5 0.1 61.7 60.2 2.3 0.6 28.7 crikvenica 45°10’ 14°42’ 2 36.2 101.6 25.5 3.6 3.6 7.3 drežnica – – – 117.0 135.9 84.4 30.4 18.0 – krk 45°02’ 14°35’ 12 16.7 75.0 75.2 3.4 1.6 36.1 kukuljanovo 45°20’ 14°32’ 355 50.0 77.7 35.5 2.7 1.2 – labin 45°05’ 14°08’ 320 23.0 40.0 39.0 1.1 0.0. – lokve 45°21’ 14°45’ 721 64.4 119.3 52.0 11.0 3.1 – malinska 45°07’ 14°32’ 1 72.0 84.1 58.1 22.8 7.0 32.6 omišalj airport 45°13’ 14°35’ 85 38.8 69.6 40.3 3.5 1.8 18.7 pula 44°52’ 13°51’ 30 0.0 59.2 23.5 0.3 0.0 – pula airport 44°54’ 13°55’ 63 0.0 76.6 31.5 0.5 0.0 – rab 44°45’ 14°46’ 24 3.8 100.7 22.2 4.0 2.4 10.1 rijeka 45°20’ 14°27’ 104 37.6 95.0 38.7 1.0 0.3 – senj 45°00’ 14°54’ 26 81.3 104.5 54.5 5.0 3.0 28.0 volosko 45°06’ 14°19’ 46 45.0 98.0 32.7 0.7 0.3 – vrh učke 45°17’ 14°12’ 1372 18.9 104.8 55.1 0.0 0.0 – zavižan 44°49’ 14°59’ 1594 1.9 193.9 94.3 20.0 10.2 – fi gu re 8: isolines of the daily precipitation volume at the 19 surrounding meteorological stations on september 11th 2007. geologia croatica 64/1geologia croatica 76 orological station data were used (table 6). in our opinion those data are reliable for the studied area and are adequate for estimation of the real discharge during the event at the gully mouth of potovošća. rainfall intensities have been calculated based on hourly rainfall intensities from 1–3am at the senj meteorological station (table 6) on september 11 (data obtained from the meteorological and hydrological service in zagreb, 2010). the obtained intensities of 0.009 mm/s for the period between 1 and 2 am, and 0.014 mm/s for the period between 2 and 3am (table 6) indicates, that, in relation to the idf curve, those values appear in the recurrent periods of 1.25 years and 5 years respectively (table 4). the total amount of rainfall which fell between 1 and 3am give the intensity of 0.011 mm/s which corresponds to the 10 year recurrent period (table 4). when those data were inserted into the rational formula with the parameters of the potovošća drainage basin we obtained a discharge for the 2–3am observed period of 13.56 m3/s which respectively corresponds to the maximum discharge for the recurrent period of 1.25 years. even if the daily precipitation volume was smaller on krk island compared to the senj area, the higher api for the krk and malinska stations, compared to the senj station (table 3) indicates signifi cant saturation of the soil consequently leading to increased runoff in the studied drainage basin producing the exposed morphological changes. 4. discussion analysis of the short-term rainfall event exposed in the potovošća gully reveals numerous factors which infl uence beach morphology and the beach sediment budget. generally the physiographic properties of the particular region are the sum of tectonic activity, geomorphological activity, and both short-term and medium-term processes repeated through geologic time. in time, individual landforms recording short time-scale events are obliterated and/or preserved as sporadic relicts. processes operating over longer timescales are generally the sum of processes operating over shorter time-scales (keller & pinter, 2002). an important parameter of beach dynamics relates to the beach sediment budget. it is well known that fan morphology is generally a function of the size of the drainage basin contributing sediments to the fan, together with geological and geomorphological properties including, tectonic activity, climate and vegetation. as the potovošća beach is formed of proluvial fan material the beach sediment budget is related to the aforementioned properties. one of these relationships has been recently studied by benac et al. (2010). on the basis of a clear correlation between the size of the drainage basin and the size of the beach formed in accumulated gully deposits, the authors concluded that the beach surfaces in the kvarner area primarily depend on the size of their catchment areas. if the data from the potovošća gully (surface of the drainage area – 334.789 ´ 104m2 and surface of the beach 2374.1 m2) is compared with the southwestern krk pilot area of benac et al. (2010) our results show that the beach of potovošća is 18% bigger, than expected according to the size of its drainage basin (expected size 1948 m2 corresponding to the linear regression y=4.650x + 391.6). this is probably due to its sheltered position toward southern winds. this allows us to conclude that the surface of of the potovošća gully beach is in correlation with the size of its drainage basin. recent sediment supply to the potovošća beach is also infl uenced by different anthropogenic activities which can have short-term and also medium-term effects. human impact on the natural shoreline is very strongly expressed totable 4: the rainfall intensity in mm/s calculated for the potovošća drainage basin for recurrent periods p (in years). min p 1.25 p 2 p 5 p 10 p 20 p 50 p 100 10’ 0.028 0.032 0.037 0.039 0.043 0.045 0.046 20’ 0.018 0.021 0.025 0.027 0.031 0.034 0.037 30’ 0.014 0.016 0.020 0.022 0.026 0.029 0.032 40’ 0.012 0.014 0.016 0.019 0.023 0.026 0.029 1h 0.009 0.011 0.013 0.016 0.019 0.022 0.025 2h 0.006 0.007 0.009 0.011 0.014 0.017 0.020 table 5: rainfall intensity tc and maximal (peak) discharge calculated for the potovošća drainage basin according to the recurrent periods recurrent interval (years) 1.25 2 5 10 20 50 100 rainfall intensity (mm/s) 0.014 0.016 0.020 0.022 0.026 0.029 0.032 stream discharge q (m3/s) 14 16 20 22 26 29 32 table 6: hourly rainfall time series for senj meteorological station for the night from 10th to 11th september 2007 hours 23–24 0–1 1–2 2–3 3–4 4–5 5–6 6–7 7–8 8–9 9–10 10–11 rainfall (mm) – – 32.2 48.6 0.1 0.3 0.1 – 19 5 1 0.1 duration (min) – – 60 60 30 20 40 – 60 60 60 20 rainfall intensity (mm/s) – – 0.009 0.014 0.000 0.000 0.000 – 0.005 0.001 0.000 0.000 faivre et al.: the gully of potovošća on the island of krk – the eff ects of a short-term rainfall event geologia croatica 77 day. changes in the beach equilibrium induced by man are observed on numerous beaches. the beaches formed in the fan material of the drowned torrent karstic valleys could be affected due to interventions along the watercourses, which diminish the natural supply of beach material (juračić et al., 2009). in such a way, many torrent valleys are completely dry today and their mouths are often fi lled with concrete (like the gully in the town of vrbnik, luka vrbnik). on the other hand, man-made constructions along the coast have also provided extra material, which enlarges natural beaches (rajčić et al., 2010). for example, according to preliminary, and unpublished results, the beach of prva draga gully in the town of senj has been enlarged by 12 m over the last 35 years as a result of human interventions along the nearby coast providing additional sediments, which then accumulated on the beach due to longshore drift (faivre, unpublished). the human impact encompasses not only the beach morphology. it is important for the larger area which evolved under the infl uence of the traditional agriculture that developed under the mediterranean conditions (aničić et al., 2004). the dry-walls are typical structures of the area. they were constructed at the end of the gully, on the proluvial fan, 37 m from the sea (fig. 3). those structures were used to prevent soil erosion as the proluvial fans generally represented areas with potentially fertile soils, which are rare in karst areas. in the last century, this area was used for cultivation of vineyards, while those structures are mainly used today as barriers for sheep. consequently, such structures directly infl uence sediment supply, even if the straight central part of the gully between the dry walls is open. after a period of strong human impact on the karst area, the cessation of agricultural activities following world war ii caused regernation of vegetation that is also refl ected in a change in the runoff regime. both facts (dry walls and vegetation regeneration) directly result in low sediment supply to the present beach. therefore, torrential fl ow, together with fresh water sources, is the main morphological short-term infl uence on present beach morphology. as the beach has been under concession since 2006, and is artifi cially levelled for tourism purposes, this has surely additionally increased the explained short-term effect on the beach. as shown in this study, short-term effects on the area can be induced principally by extreme weather conditions such as high precipitation intensity and wave climatic regimes which leave their mark on the beach. however, the rainfall-runoff relationship directly relates topography to event specifi c conditions. topography of the drainage basin is an important parameter in this study as according to yilmaz (2009) the spatial variation of hydrological conditions is fi rstly controlled by topography. primary topographical attributes, such as slope and aspect, are calculated from the directional derivatives of a topographic surface (gallant & wilson, 2000). alternatively, secondary topographical attributes are computed from two or more primary attributes. according to gallant & wilson (2000), the majority of these secondary attributes come from the ability of describing patterns as a function of process. catchments are dissipative systems in that energy is released as precipitation travels through the catchment and performs work on the landscape. energy dissipation in river systems is equivalent to stream power (mcnamara et al., 2006). the distribution of energy index produces distinct domains in slope-area space that partition the landscape according to erosion mechanisms (mcnamara et al., 2006). therefore, the topographical index considered in this study, the stream power index is often used at present when studying the geomorphologic (topographic) thresholds in gully development (mcnamara et al., 2006; kakembo et al., 2009). kakembo et al. (2009) separate out a specifi c threshold zone (of 2 to 6 spi values) for gully development along the spi continuum. consequently the calculated spi for the potovošća drainage basin which range from (0−5.4) confi rms the existence of the appropriate energy potential for gullying. due to the lack of precise meteorological data for the studied area, assessment of the event specifi c conditions was much harder. although parameter analysis of the expected annual maximum daily precipitation wasn’t conducted, results obtained for the nearby stations (176.9 mm for crikvenica, 160.6 mm for senj and 120.2 mm for rab; gajićčapka & čapka, 1997) for the shortest published return period of 20 years show that the precipitation amount that fell on 11th of september on the studied area was much lower. however, hourly rainfall data calculated for the senj meteorological station indicate that 2 hours precipitation intensities (for 80.8 mm precipitation volume) correspond to the 10 years recurrent period (table 6). the time of concentration of the potovošća drainage basin has been calculated to 29.7 min which is signifi cantly lower from the time interval of the available data on the registered short-term precipitations on the closest ombrograph station at senj (horary data). given that during this precipitation episode almost the total daily precipitation amount of 81.3 mm fell in two hours, together with the fact that the drainage basin of the potovošća gully received a much smaller precipitation amount (fig. 8), some correlations can be made concerning the occurrence of maximum discharges. the, two hourly precipitation of 40 mm (average 2 hours intensity of 0.0056 mm/s) has a characteristic return period of 1.25 years, that is, an 80% probability of occurrence. at the senj station, the hourly intensity was already achieved during the second hour (counting from the onset of precipitation), therefore, under conditions of the greater water saturation of soil, it is to be expected that the peak discharge of the potovošća gully in similar conditions was somewhat greater than calculated for the 1.25 yearly recurrent period (table 5) but not signifi cantly different from the order of magnitude of the 2 year recurrent period. therefore, it deals with the runoff which had the character of an extreme event on the scale of 1 year but does not represent a particularly rare extreme event over a longer time scale. but the calculated api for the potovošća drainage basin which is relatively high (malinska, 32.6 mm; krk 36.1 mm) can be an additional factor contributing to the higher runoff during the exposed event and consequently was of suffi cient intensity to cause the gulling processes described. geologia croatica 64/1geologia croatica 78 it is also important to emphasize the results of rubinić et al’s, (2009) study concerning the nearby rijeka meteorological station. it shows that the occurrences of short term heavy rainfall events (10 minutes – 1 hr) increase during the warm part of the year while the (6−24 hrs) rainfall events prevail mostly in the second half of the year with maximum values in august and september. it is also known that the potovošća beach has been affected by sea level rise as a long term process over a larger area (fouache et al., 2000; faivre & fouache, 2003; benac et al., 2004; benac et al., 2008), to which the beach should have been responding over the last few centuries. the response of low coasts, formed in unconsolidated sediments, to sea-level rise has been the subject of considerable scientifi c research globally for over four decades, particularly on sandy shores. it is diffi cult to take account of the “sea-level rise” parameter in quantifying shoreline evolution (dubois, 2002; brunel & sabatier, 2009). therefore, many studies of coastal erosion with sea-level rise have centred on a well-known scientifi c model known as the “bruun rule”. according to the bruun rule (bruun, 1962; bruun, 1988), if the beach profi le has reached its equilibrium, this profi le will change as a consequence of the sealevel rise. the erosion starts in its upper part and sedimentation in the infralittoral part. this process lasts until the new equilibrium profi le is achieved. the current consensus of opinion is that, whilst probably essentially valid, the standard bruun rule is a greatly simplifi ed model of coastal behaviour which needs to be supplemented with a variety of additional considerations before it can be used. brunel & sabatier (2009) adopt the principle of dynamic – active submersion for sandy beaches, assuming that the slope of the beach profi le remains identical in time and migrates horizontally towards the land when sea level rises in the case of no major sediment input and if there is space available in the background. however, the response of dominantly pebble beaches to sea-level rise is even less clear than the response of sandy beaches. the potovošća beach has also been recently submitted to sea-level change and consequently, in our opinion, most likely to the landward migration of the beach profi le. this short event showed that the former large fan is related to different formation conditions, that is, to long-term evolution. it was formed during lower sea level while the two fans that formed during the short-term event do not correspond to the morphology of the major older fan. as we know that during the last few centuries the beach has also experienced recent submergence and from the new profi les which revealed an older torrent bed, 60 cm below the recent beach surface, we assume the landward migration of the beach as a long-lasting process. we hope to determine more about the shortand long-term infl uences on evolution of the pocket beaches in the future by continuing to monitor the beach profi le. 5. conclusion this research allows determination of the main geomorphological properties of the gully of potovošća from which the high erodability potential is derived. overall, 80.9% of the drainage basin is included in two slope inclination classes, 5−32° in which gullying processes are the most effective. the analysis of the stream power index, provides more details on the potential energy distribution in the potovošća drainage basin (vary from 0−5.4). the highest values (3.2−5.4) are obtained in the upper parts of the drainage basin as well as along the main gully and tributary gully beds. in these appropriate morphological conditions the infl uence of a short heavy rainfall event was examined. the torrential fl ow together with the fresh water sources induces gullying in the beach, causing the formation of 80 cm deep gullies and results in two new submarine fans. during the night of the 10th−11th september 2007, the three meteorological stations (omišalj, senj and malinska) had precipitation amount extremely above normal (above +3 σ). according to the interpolated values, the rainfall volume for the potovošća area amounted to 40 mm. the precipitation intensity can be highly variable in space and depends on numerous factors, but, as the two nearby stations had much higher amounts of precipitation (senj and malinska) it is assumed that the volume of rainfall on the investigated area was also probably higher. therefore it can be concluded that 40 mm of precipitation volume preceded with relatively high api value is the minimum value that can produce runoff estimated to be 14 m3/s and displaced 130±10% m3 of beach sediments. in addition, according to this study similar strong gullying events can be expected over a larger studied area principally in september. this gullying effect was also intensifi ed due to human interference on the beach surface. this example clearly shows the rapid changes of beach morphometry, which are primarily related to the precipitation and wave climatic conditions. that is, it was also observed that beaches with a predominance of pebbles respond to storms to some extent with an offshore movement of larger particles, followed by later return of smaller particles to the beach. this study shows that coastal landforms illustrate well the relative role of time-scale in landscape evolution. the explained short event also revealed aspects of long-term beach evolution. the well known context of sea level rise at the eastern adriatic coast implies that the beach has also experienced recent submergence and that the beach profi le should have adjusted to those changes, e.g. probable landward migration of the beach. as the expected sea level change during the 21 century amounts from 20 to 60 cm (antonioli & silenci, 2007), this trend will probably mark the future evolution of the beach. as we know, the most vulnerable areas in the kvarner area are the beaches (benac et al., 2007; juračić et al., 2009). according to the recent morphological situation the landward migration of the potovošća shoreline is still possible because the beach narrowing due to the relative sealevel change won’t be important by the end of this century. as the episodic recurrence of similar gullying events in the past was well observed in the profi le of the eastern gully, it is expected that, due to the climate change, the frequency faivre et al.: the gully of potovošća on the island of krk – the eff ects of a short-term rainfall event geologia croatica 79 of future short-term climate events will increase (sánchez et al., 2004; semmler & jacob, 2004; planton et al., 2008). consequently, it can be assumed that the frequency of the events described here will also increase. the effects of the 10−11 september 2007 short-term event demonstrate the relative roles of natural processes and minimum human interference, which will surely increase in the future, in determining the evolution of the investigated area. acknowledgement this research was supported by the ministry of science, education and sport of the republic of croatia (project 1191191306-1305). the contribution of the meteorological and hydrological service in zagreb is warmly acknowledged. we are especially grateful to dr. mira pasarić for the corrections of the mareograph data, and remain indebted to ivica rendulić for drawing of fi gures. the authors wish to thank the two anonymous reviewers for their constructive comments which substantially improved the submitted manuscript. reference aničić, b., reichner, i. & perica, d. (2004): structural vocabulary of cultural landscape on the island of krk (croatia).– acta carsologica, 33/1, 7, 101–115. antonioli, f. & silenzi, s. (2007): variazioni relative del livello del mare e vulnerabilità delle pianure coastiere italiane.– quaderni soc. geol. ital., 2, 1−29. benac, č. (1992):recentni geomorfološki procesi i oblici u području riječkog zaljeva [the recent geomorphological processes in the area of the rijeka bay – in croatian, with an english abstract].– geografski glasnik, 54, 1−18. benac, č. (1996): rast morske razine i promjena reljefa na obalama kvarnera [sea level rise and coastal changes in the kvarner area – in croatian, with an english abstract].– pomorski zbornik, 34/1, 345−359. benac, č., arbanas, ž. & pavlovec, e. (1991): postanak i geoteh ničke osobitosti doline i zaljeva raše [the origin and the geote chnical properties of the valley and the bay of the river raša – in croatian, with an english abstract].– pomorski zbornik, 29, 475–492. benac, č., juračić, m. & bakran-petricioli, t. (2004): submerged tidal notches in the rijeka bay ne adriatic sea: indicators of relative sea-level change and of recent tectonic movements.– mar. geol. 212/1–4, 21–33. benac, č., juračić, m. & blašković, i. (2008): tidal notches in vinodol channel and bakar bay, ne adriatic sea: indicators of recent tectonics.– mar. geol., 248/3–4, 151–160. benac, č., ružić, i. & ilić, s. (2010): morfodinamika minijaturnih žala (kvarner, sjeveroistočni jadran) [morphodynamics of pocket beaches (kvarner, ne adriatic sea – in croatian].– abstracts book, 4th croatian geological congress, šibenik, 2010, 384−385. benac, č., ružić, i. & žic, e. (2007): ranjivost obala u području kvarnera [coastal vulnerability within the kvarner littoral – in croa tian, with an english abstract].– pomorski zbornik, 44, 201−214. bird, e. (2008): coastal geomorphology, an introduction.– wiley, chichester, 411 p. brunel, c. & sabatier, f. (2009): potential infl uence of sea-level rise in controlling shoreline position on the french mediterranean coast.− geomorphology, 107, 47−57. bruun, p. (1962): sea-level rise as a cause of shore erosion.– journal of waterways and harbors. proceedings of the american society of civil engineers, 88, 117–130. bruun, p. (1988): the bruun rule of erosion by sea-level rise: a discussion of large-scale twoand three – dimensional usages.– j. coastal res., 4/4, 627–648. descroix, l., nouvelot, j.f. & vauclin, m. (2002): evaluation of an antecedent precipitation index to model runoff yield in the western sierra madre (north-west mexico).– journal of hydrology, 263, 114−160. chow, v.t. (1988): handbook of applied hydrology.− mcgraw-hill book company, 1964. conrad, v. & pollak, l.w. (1950): methods in climatology.– harvard university press, cambridge, 459 p. dubois, r.n. (1988): seasonal changes in beach topography and beach volume in delaware.– mar. geol., 81/1–4, 79–96. dubois, r.n. (2002): how does a barrier shoreface respond to a sealevel rise?− journal of coastal research, 18, editorial, iii-v. faivre, s. & fouache, e. (2003): some tectonic infl uences on the croatian shoreline evolution in the last 2000 years.– z. geomorph. n.f., 47/4, 521–537. faivre, s., fouache, e., ghilardi, m., antonioli, f., furlani, s. & kovačić, v. (2011): relative sea-level change in istria (croatia) during the last millenia.– quaternary international 232, 132–143. fouache, e., faivre, s., dufaure, j-j., kovačić, v. & tassaux, f. (2000): new observations on the evolution of the croatian shoreline between poreč and zadar over the past 2000 years.– z. geomorph. n.f. suppl.–bd., 122, 33–46. gajić-čapka, m. & čapka, b. (1997): procjene maksimalnih dnevnih količina oborine [analysis of annual maximum daily precipitation – in croatian, with an english abstract].– hrvatske vode, 5/20, 231−247. gajić-čapka, m. (1999): duljina normalnog niza za kratkotrajne oborine u hrvatskoj [length of the normal series for short-term rainfalls in croatia – in croatian, with an english abstract].− hrvatske vode, 7, 29, 367−380. gajić-čapka, m. (2002): regionalna analiza učestalosti ekstremnih oborina [regional analysis of extreme rainfall frequency – in croatian, with an english abstract].– urbana hidrologija, zbornik radova okruglog stola, split, 91−99. gallant, j.c. & wilson, j.p. (2000): primary topographic attributes.− in: wilson, j.p. & gallant, j.c. (eds.): terrain analy sis – principles and applications. john wiley & sons, 51–85. heggen, r.j. (2001): normalized antecedent precipitation index.– j. hydrol. eng., 6/5, 377−381. juračić, m., benac, č., pikelj, k. & ilić, s. (2009): comparison of the vulnerability of limestone (karst) and siliciclastic coasts (example from the kvarner area, ne adriatic, croatia).– geomorphology, 107/1–2, 90–99. juračić, m., benac, č. & crmarić, r. (1999): seabed and surface sediment map of the kvarner region, adriatic sea, croatia (lithological map, 1:500 000).– geol. croat., 52/2, 131−140. kakembo, v., xanga, w.w. & rowntree, k. (2009): topographic thresholds in gully development on the hillslopes of communal areas in ngqushwa local municipality, eastern cape, south africa.– geomorphology, 110, 188–194. keller, e.a. & pinter, n. (2002): active tectonics: eartquakes, uplift and landscape. 2nd edition.− prentice hall, new jersey, 362 p. kirpich, z.p. (1940): time of concentration of small agricultural watersheds.– civil engineering (n.y.), 10/6, 362. kovář, p. (2004): risk assessment of extreme hydrological situations case study of the vseminka and drevnice catchments, czech regeologia croatica 64/1geologia croatica 80 public, anti-erosive and water-protective role of the forest and methods of its preservation and improvement, international scientifi c symposium, zagreb, 23.11.29, 36 p. kuichling, e. (1889): the relation between the rainfall and the discharge of sewers in populous districts.– transactions, american society of civil engineers, 20, 1−56. mccuen, r.h., wong, s.l. & rawls, w.j. (1984): estimating urban time of concentration.– j. hydraul. eng., 110/7, 887–904. mcnamara, j.p., ziegler, a.d., wood, s.h., john, b. & vogler, j.b. (2006): channel head locations with respect to geomorphologic thresholds derived from a digital elevation model: a case study in northern thailand.– forest ecology and management, 224, 1−2, 15 march 2006, 147−156. moore, i.d., grayson, r.b. & ladson, a.r. (1991): digital terrain modeling: a review of hydrological, geomorphological, and biological applications.– hydrol. process., 5, 3–30. mulvaney, t.j. (1851): on the use of self-registering rain and fl ood gauges in making observations of the relations of rainfall and of fl ood discharges in a given catchment.− trans. inst. civil engrs. ir. (dublin), 4/2, 18. patil, s.r. (2008): regionalization of an event based nash cascade model for flood predictions in ungauged basins.− institut für wasserbau, universität stuttgart, heft 175, 107 p. pirazzoli, p.a. (1993): les littoraux.– nathan universite, paris, 191 p. planton, s., déqué, m., chauvin, f. & terray, l. (2008): expected impacts of climate change on extreme climate events.– c.r. geoscience, 340, 564–574. rajčić, s.t., faivre, s. & buzjak (2010): promjene žala na području medića i mimica od kraja 1960-tih godina do danas [the variations of the beach surfaces on the area of medići and mimice from 1960 till today – in croatian, with an english abstract].– hrvatski geografski glasnik, 72/2, 27−48. rubinić, j. (2003): inženjerska obrada kratkotrajnih intenziteta oborina [engineering analysis of short-term heavy rainfalls – in croatian].– praktična hidrologija, zbornik radova, zagreb, 37−60. rubinić, j. (2006): inžinjerska analiza oborinskog režima područja općine punat na otoku krku [engineering analysis of the precipitation pattern of the punat country at the krk island – in croatian].− elaborate, 21 p. rubinić, j., gajić-čapka, m., milković, j. & ožanić, n. (1995): intenziteti oborine – problemi obrade i interpretacije u praksi [precipitation intensity – problems of analysis and interpretation in practice – in croatian].− uloga hidrologije u gospodarstvu hrvatske, zbornik radova okruglog stola, zagreb, 53−69. rubinić, j., lukarić, s. & rukavina, j. (2009): inženjersko sagledavanje kratkotrajnih jakih oborina – primjer riječkog područja [engineering analysis of short-term heavy rainfalls – in croatian, with an english abstract].– suvremene metode odvodnje oborinskih voda urbanih sredina na obalnim područjima, zbornik radova, rijeka, 176−193. sánchez, e., gallardo, c., gaertner, m.a., arribas, a. & castro, m. (2004): future climate extreme events in the mediterranean simulated by a regional climate model: a fi rst approach.– global planet. change, 44, 163–180. šegota, t. & filipčić, a. (1996): klimatologija za geografe [climatology for geographers – in croatian].– školska knjiga, zagreb, 472 p. semmler, t. & jacob, d. (2004): modeling extreme precipitation events – a climate change simulation for europe.– global planet. change, 44, 119–127. stephenson, w.j. & brander, r. (2003): coastal geomorphology into the twenty-fi rst century.– prog. in phys. geog., 27/4, 607−623. storlazzi, c.d. & field, m.e. (2000): sediment distribution and transport along the rocky coast, embayed coast: monterey peninsula and carmel bay, california.– marine geol., 170/3−4, 289−316. šušnjar, m., bukovac, j., nikler, l., crnolatac, i., milan, a., šikić, d., grimani, i., vulić, ž. & blašković, i. (1970): osnovna geološka karta sfrj 1:100.000, list crikvenica l33–102 [basic geological map of the sfry 1:100.000, the crikvenica sheet – in croatian].– institut za geološka istraživanja zagreb (1969), savezni geološki zavod, beograd. tagil, s. & jenness, j. (2008): gis-based automated landform classifi cation and topographic, landcover and geologic attributes of landforms around the yazoren polje, turkey.– journal of applied sciences, 8, 910–921. thompson, d.b. (2006): the rational method, http://drdbthompson. net /writings/rational.pdf, 22.10.2010. yilmaz, i. (2009): landslide susceptibility mapping using frequency ratio, logistic regression, artifi cial neural networks and their comparison: a case study from kat landslides (tokat–turkey).– computers & geosciences, 35/6, 1125−1138. žugaj, r. (2000): hidrologija [hydrology – in croatian]. sveučilište u zagrebu, rudarsko-geo loško-naftni fakultet, zagreb, 407 p. manuscript received february 19, 2010 revised manuscript accepted january 24, 2011 available online february 22, 2011 01 gourvennec.indd 1. introduction the taurus mountains are one of the major tectonic units of southern turkey, and many palaeozoic outcrops have been recorded in this area, where the succession ranges from cambrian to miocene in age with many unconformities. the devonian series show a regressive tendency following the transgressive sequence of the silurian (see gedik, 1988, for a general overview of the devonian of turkey). the studied section is located ne of kozan, on the road between kozan and feke, along the edge of kilgen lake, in se turkey, eastern part of the taurids (fig. 1). from east to west, the succession includes the ordovician series (seydisehir fm., kozan fm., sortepe fm. and halevikdere fm.) followed by silurian black shales and limestones. the upper part of the latter, consisting of limestones lying unconformably on the rest of the formation and underlying the mesozoic formations, has yielded a fauna mainly consisting of brachiopods and corals. although this succession was formerly considered as entirely silurian, the brachiopod fauna collected in this upper part indicates a late devonian age, probably early frasnian. the age of the series is thus reassessed on this basis. only the brachiopods are described here; study of the corals is in progress and they will be described in a future publication. upper devonian brachiopods from eastern taurus (turkey) rémy gourvennec 2. systematic palaeontology note on the terminology the abbreviations used in the text and tables are the following: l – length measured from the hinge to the anterior commissure; lt – total length including the beak; w – maximum width; wh – width of the hinge line; ws – width of the sulcus or fold at the anterior commissure; hd and hv – height (i.e. depth) of the dorsal and ventral valves respectively; h – total height (i.e. thickness) of the shell; ncf and ncs – number of ribs (or costae) on one flank and sulcus or fold respectively; ncp – number of parietal ribs. all measurements are in mm. the material is housed in the laboratoire de paléontologie de brest, france (numbers lpb). order strophomenida öpik, 1934 superfamily strophomenoidea king, 1846 family douvillinidae caster, 1939 genus douvillina oehlert, 1887 type species: orthis dutertrei murchison, 1840, p. 253. douvillina sp. pl. 1, fig. 1 material one shell fragment showing the ornament; another fragment showing the ventral muscle field. lpb 12400. kozan section, level pk66 c. description the shell has a low, planar, vertically striated interarea and a denticulate hinge. the delthyrium is triangular, partly filled by the basal thickening of the myophragm. the ornament is parvicostellate with well marked radial costae separated by wide, flat interspaces bearing fine costellae (2–3 costellae between primary costae), and tending to become stronger anteriorwards. very fine concentric growth lines are also present on weakly expressed “rugae”. in the ventral valve, fine radial striae resulting from the alignment of numerous closely spaced small pits occur. they are separated by radial grooves, some of them deeper, mimicking the external ornament. the geologia croatica 59/1 1–17 1 fig. 4 tabs. 2 pls. zagreb 2006 key words: brachiopods, upper devonian, gondwana, cimmerian belt, turkey. umr 6538 “domaines océaniques”, université de bretagne occidentale. ufr sciences & techniques. 6, avenue le gorgeu, cs 93837, f-29238 brest cedex 3, france; e-mail: remy.gourvennec@univ-brest.fr abstract during a field expedition in taurus (se turkey) in order to study the lower palaeozoic series, a small brachiopod fauna was collected in the kozan area in beds of supposed silurian age. after closer examination, the age of this fauna is clearly upper devonian, probably lower frasnian, and this implies a reassessment of the age of the series. this assemblage also shows close affinities with similar north gondwanan faunas described in iran and afghanistan in beds of the same age. 2 geologia croatica 59/1 muscle field is elevated, giving rise to a transverse, concave platform clearly delimited by an elevated ridge. it is crossed by a strong but relatively low median myophragm that does not run beyond the anterior edge of the muscle field. discussion the internal features and ornament are consistent with an assignment of this species to douvillina oehlert, 1887. d. ferquensis (rigaux, 1872) shows a similar ornament and arrangement of the internal pits related to the external ornament, but it differs in a longer myophragm that crosses the anterior margin of the muscle field. the ornament of some other species (e.g. d. aronovae ljaschenko, 1952 in ljaschenko, 1959) evokes the ornament of the present species, but due to the lack of material, it is difficult to make solid comparisons. these two species are known in frasnian successions of western europe and the russian platform respectively. order productida sarytcheva & sokolskaja, 1959 suborder productidina waagen, 1883 superfamily productoidea gray, 1840 family productellidae, schuchert, 1929 genus productella hall, 1867 type species: productus subaculeatus murchison, 1840, p. 255. productella sp. cf. subaculeata (murchison, 1840) pl. 1, figs. 2–5 material four almost complete variably damaged specimens, and two partially exfoliated ventral valves; lpb 12401 – lpb 12402. kozan section, levels pk66 a and c. description small to medium size (means: l=18.3 mm; w=21.6 mm; h=8.7 mm), strongly concavo–convex with variable outline (rounded subquadratic to slightly transverse), with a hinge line slightly shorter than maximum width. the areas are discrete, very low, but distinguishable on most specimens and longitudinally striate; the angle between them varies from 90 to 130°. the delthyrium is broad, low, with no trace of deltidial cover. all the umbos are damaged, except on one specimen that shows no trace of an attachment cicatrix. chilidium lacking. the shell bears fine, concentric sinuous growth lines and coarser, sinuous rugae which are stronger on the postero–lateral parts of the shell. the latter are somewhat more conspicuous on the dorsal valve surface. they are generally low except on one specimen where they are well developed on the entire anterior half of the shell on both valves, and particularly well marked on the dorsal one. the spines, present on the ventral valve only, are long, hollow, numerous, recumbent, and distributed along the rugae in alternate rows resulting in an irregufig. 1 location map and lithostratigraphic column of the kozan section, se turkey. the fauna described in this paper was sampled from the top of the series (level pk 66). 3gourvennec: upper devonian brachiopods from eastern taurus (turkey) lar staggered implantation. however, due to the irregularity of the rugae, they often appear as randomly distributed, particularly on abraded shells. they can be locally more or less aligned radially, rarely with posterior slightly elongate ridges. no spine was observed on the dorsal valve where they are replaced by small dimples approximately distributed in the same way as spines on the opposite valve. due to lack of internal molds, the internal structures were not observed in detail. nevertheless, two shells, partially exfoliated in their apical part, show a bifid cardinal process with high, divergent lobes and small sockets with short, rounded, slightly internally recurved teeth. discussion the lack of ribs and cicatrix attachment, absence of spines in the dorsal valve, and the presence of teeth plead in favour of an assignment to productella hall, 1867. the closely related genus spinulicosta nalivkin, 1937 shows a tendency to anterior ribbing, which is not the case here, and its spines generally originate from elongate spine bases. donalosia lazarev, 1989 presents a similar external aspect, but in donalosia the spines are stronger and more numerous in the postero–lateral region, unlike the present form. praewaagenoconcha sokolskaja, 1948 has a row of stronger median spines on the ventral valve, and eostrophalosia stainbrook, 1943 has spines on the dorsal valve. among the species belonging to the genus, p. subaculeata (murchison, 1840) seems to be the better receptacle, although the spines are generally described as randomly distributed in this species, which is not exactly the case here, and less numerous (after the original figure in murchison, 1840, pl. 2, fig. 9). as established by brousmiche (1973) the species is highly variable in size, outline and ornament, but the different morphotypes described by this author always show relatively coarser spines than our specimens. we thus maintain this material in open nomenclature although the remaining characters are in good accordance with an assignment to p. subaculeata. among other close species, p. belanskii stainbrook, 1943 has a row of median stronger spines and elongated spine bases. p. subaculeata is known in middle and upper devonian series from europe, asia, america, and africa. order rhynchonellida kuhn, 1949 superfamily rhynchotrematoidea schuchert, 1913 family trigonirhynchiidae schmidt, 1965 genus cupularostrum sartenaer, 1961 type species: cupularostrum recticostatum sartenaer, 1961, p. 2. cupularostrum? sp. material one complete crushed shell; lpb 12430. kozan section, level pk66 c. description this relatively large, moderately biconvex shell (lt=27.5 mm; w=29 mm; h~15 mm) has a subcircular outline. sulcus and fold are not expressed or weak near the anterior margin that is damaged; the tongue was probably low. the ribs are numerous (nc~50 over the entire shell), simple, angular, relatively strong, the median ones slightly stronger than lateral ones. the apices are smooth. the interior is unknown. discussion owing to the lack of information on the interior and the damaged commissure, this specimen is here assigned with doubt to cupularostrum sartenaer, 1961. it also presents some analogies with comiotoechia ljaschenko, 1973 in its general aspect, but is larger, with coarser ribs. genus rhipidiorhynchus sartenaer, 1966a type species: terebratula livonica von buch, 1834, p. 57. rhipidiorhynchus cf. elburzensis (gaetani, 1965) pl. 1, figs. 10–13 material only one crushed but complete specimen; lpb 12403. kozan section, level pk66 b. description shell small (l=14 mm; w=14 mm), subquadratic, strongly inequivalve (hd=8.5 mm; hv~2.5 mm), with a maximum width located about mid-length. the maximum height is located at the front. ventral valve very low and concave (but this may be due to deformation). the beak is well developed, erect. the sulcus is clearly delimited, deep, wide (ws/w=0.5 at front) with steep flanks, and originates in the posterior part of the valve, not very far from the apex. the tongue is high, trapezoidal. dorsal valve very high, convex, with an obviously delimited, high fold, originating in early stages of growth. ornament of simple, rounded to subangular ribs, beginning at the apex and bearing very fine concentric growth lines (8 per mm). there are 3 ribs in the sulcus, 2 parietal ribs that do not reach the commissure, and 8–10 lateral ribs on each flank. the ribs on the fold are somewhat stronger than the others. internal characters are unknown. 4 geologia croatica 59/1 discussion this species is assigned to the genus rhipidiorhynchus sartenaer, 1966a on the basis of its ornament beginning at the apex, its sinal formula, the development and shape of the fold/sulcus, the erect beak, etc. due to the lack of material, a specific assignment is unsure. this form is close to r. elburzensis (gaetani, 1965) that was identified in the frasnian of iran and afghanistan and differs by its larger size and higher number of lateral ribs (but this is not significant in regard of the number of specimens available here). r. farsani brice, 1976 is also smaller with a different rib formula. another closely related species, r. ferquensis (gosselet, 1887) is also discarded for the same reasons. the latter two are known in frasnian successions, in afghanistan and europe respectively. genus cyphoterorhynchus sartenaer, 1965 type species: uncinulus (uncinulina) koraghensis reed, 1922, p. 40. cyphoterorhynchus koraghensis (reed, 1922) pl. 1, figs. 19–23; table 1 1922 uncinulus (uncinula) koraghensis sp. nov. reed, p. 40, pl. 7, figs. 10–22; pl. 8, fig. 1 1971 cyphoterorhynchus koraghensis (reed, 1922) – brice, p. 47, pl. 3, figs. 1a–d, 6 a–d; text-fig. 13a (with a comprehensive synonymy). material seven articulated shells; lpb 12437– lpb 12439. kozan section, levels pk66 a, c and d. description shell relatively large (means: lt=22.3 mm; w=22.2 mm; h=19 mm) (table 1), strongly dorsi–biconvex with subcircular to slightly transverse outline and vertical or subvertical lateral margins. the maximum height is located at mid-length, occasionally between mid-length and the anterior third of the shell. the sulcus and fold are poorly delimited and weak in the posterior part of the shell. they are also weak in the anterior half. the bottom of the sulcus is slightly convex. the tongue is high, vertical with subtrapezoidal outline. the anterior and lateral commissures are serrate. the ribs originate at the apex, are relatively strong, rounded to angular, never flattening anteriorly. there are usually 5 to 7 ribs in the sulcus and 1 (rarely 2) parietal rib(s) that invariably disappear anteriorly. each flank bears 10 to 15 ribs (mean ncf=12), the posterolateral ones being very faint. table 1 measurements (in mm) of cyphoterorhynchus koraghensis (reed, 1922) and c. arpaensis (abramian, 1957) from the kozan section, near kilgen lake, se turkey. sample lt w hd hv ncs ncp ncf c. koraghensis lpb 12437 — — — — 4 1 >12 lpb 12438a 25.5 25.5 15 8.5 6 1 10 lpb 12438b 21.5 21.5 12 6 5 1 10–12 lpb 12438c 21.5 24 12 5.5 5 1 10 lpb 12439a 21 20.5 11 7 6 1 (2?) > 13 lpb 12439b 22 21 13 5.5 7 2 ≈15 lpb 12439c 22.5 20.5 13 5.5 7 1–2 14 means 22.3 22.2 12.7 6.3 ≈6 ≈1 ≈12 c. arpaensis lpb 12431a 22.5 23 10 5 6 4 13 lpb 12431b 21.5 20 13 5 7–8 2 >18 lpb 12432 22 22 15 5 7 2 >17 lpb 12433a 19.5 20 11 6 7 3 >18 lpb 12433b 17 17 8 4 8 3 >13 lpb 12434a 27 22 12 7 ≈9 3 >19 lpb 12434b 19.5 19 12 9 ≈8 3 >13 lpb 12435a 25 23.5 14 7 9 2 >16 lpb 12435b 18 18 10 5 7 2 15 lpb 12436a 22 21.5 9 7 9 3 >12 lpb 12436b 16.5 18 8 7 8 3 >13 means 21 20.4 11.1 6.1 ≈8 2–3 ≈16+ 5gourvennec: upper devonian brachiopods from eastern taurus (turkey) dorsal interior with septalium; other internal structures unknown. discussion see the discussion of c. arpaensis below. the species is known in frasnian successions of pakistan (chitral), afghanistan, and iran. cyphoterorhynchus arpaensis (abramian, 1957) pl. 1, figs. 24–28; table 1 1957 camarotoechia radiata nal. (in litt.) var. arpaensis var. nov. abramian, p. 55, pl. 5, figs. 6 a–г; pl. 6, figs. 4 a–г. 1971 cyphoterorhynchus arpaensis (abramian) – brice, p. 52, pl. 3, figs. 2 a–c, 4 a–d; text-fig. 14 a (with a comprehensive synonymy). material 14 specimens; lpb 12431 – lpb 12436. kozan section, levels pk66 a, b, c, d. description this species is very similar to the previous one and differs mainly by the shape and number of ribs that are finer, more numerous, less angular and occasionally become flattened anteriorly, with a median groove (visible on two specimens). there are 7 to 9 ribs in the sulcus and 2 or 3 parietal ribs that disappear anteriorly in about 50 percent of the specimens. in one case, there are 4 parietal ribs. the number of lateral ribs is highly variable (13 to more than 19 on each flank) (table 1). the deltidial plates are low and disjunct. ventral interior with short, thick dental plates that converge ventrally. the muscle field is excavated and crossed by a short median myophragm and a few radial grooves. a strong thickening of the shell may be present, reducing the free part of the dental plates. dorsal interior with a strong v-shaped septalium with a dorsally convex cover plate. the long, relatively high median septum is thick posteriorly and becomes abruptly thinner anteriorly. crural bases subcircular in cross-section. the imprint of the anterior and posterior adductor scars is well marked and moderately excavated. on two specimens the vascula are well developed in both valves, particularly the vascula lateralia. the vascula genitalia are distributed anterolaterally to the muscle field and consist of small tubercles more or less radially oriented and sometimes fused together, in the posterior third of the valve. discussion in this species, as for the species described above, the variability seems very pronounced. it concerns the general shape, more or less transverse, sometimes subcuboid, the number of ribs and their strength, etc. this variability both in c. koraghensis and c. arpaensis has already been observed in material described in afghanistan (brice, 1971), iran (sartenaer, 1966b) or chitral (reed, 1922). although the extremes are easily separated, the presence of transitional forms does not make it easy to distinguish the two species by their external aspect; the main criterion consists of the different sinal formulae and number of lateral ribs. some of the intermediate morphs (with 2 parietal and few lateral ribs) may belong to the subspecies c. koraghensis interpositus sartenaer, 1966b which is a transitional form between the nominal species and c. arpaensis. the two species are assigned here to cyphoterorhynchus sartenaer, 1965, following the general opinion of the authors in recent literature. nevertheless, they also show some similarities with the genus cupularostrum sartenaer, 1961 such as trapezoidal tongue, serrate commissure, distinct dental plates more or less ventrally convergent and relatively long dorsal septum. c. arpaensis has been described from the frasnian of armenia, transcaucasus, iran and afghanistan. superfamily pugnacoidea rzhonsnitskaja, 1956 family ladogiidae ljaschenko, 1973 genus ladogilina ljaschenko, 1973 type species: ladogilina rossica ljaschenko, 1973, p. 38. ladogilina sp. 1 pl.1, figs. 6–9 ; table 2 material three almost complete specimens and one crushed specimen; lpb 12426 – lpb 12428. kozan section, levels pk66 a, b, c. description shell strongly inequivalve, large (maximum: l=38 mm; w=40 mm) (table 2), with a rounded subtriangular outline. the apical angle varies from 100 to 110°. the maximum width is located near the anterior third of the shell. ventral valve low, more or less flat in transverse section, a very shallow sulcus appearing only at midlength. at the anterior edge, the tongue is very high and vertically erect, its basis occupying almost the entire width of the shell. the extremity (top) of the tongue is rounded. the beak is short, well marked, with an apparently hypothyrid foramen. dorsal valve very high and regularly increasing in height up to the frontal commissure. in transverse section, the valve is regularly rounded (semicircular shape) with a fold becoming expressed only in the anterior third of the shell. 6 geologia croatica 59/1 the entire shell is covered by numerous fine, rounded, simple ribs beginning at the apex, separated by narrow interspaces and regularly widening anteriorly. there are 8 ribs per 5 mm at 1.5 cm from the beak and 4 to 6 ribs per 5 mm at the antero–lateral commissure. the dorsal median septum is strong, particularly in its posterior part. it is long, reaching the midlength of the shell. the ventral interior features are unknown. discussion despite its subtriangular outline, this species is assigned to ladogilina rather than ladogia after the shape of its tongue (not acute as in ladogia), rounded ribs and the rounded outline in transverse section. this species is close to ladogilina persanica brice, 1999, but differs by its larger size. brice (1999 – p. 73) pointed out the existence in afghanistan (robate-paï) of a large specimen close to l. persanica that “possibly belong[ed] to another species”; this specimen could be conspecific with the present one. l. rossica ljaschenko, 1973 and l. simensis (markowsky, in ellern et al., 1955) are also much smaller than the present species and have somewhat finer ribs (9 to 11 per 0.5 mm at 1.5 cm from the beak). ladogilina sp. 2 cf. l. rossica ljaschenko, 1973 pl. 1, figs. 29–33; table 2 material two complete specimens and 2 incomplete, crushed ones; lpb 12429. kozan section, level pk66 e. description shell inequivalve, relatively large, but smaller than ladogia sp. 1 (maximum: l=28 mm; w=31 mm) (table 2), with a rounded subquadrangular outline. the apical angle is about 110 to 120°. the maximum width is located in the anterior half of the shell. ventral valve lower than the dorsal one, rounded in transverse section. sulcus almost lacking or very shallow, appearing at mid-length. the tongue is widely rounded, not very high. the beak is short with a submesothyrid foramen. dorsal valve high and regularly rounded in transverse section. fold indistinct. ribs numerous and fine (11 to 12 per 5 mm at 1.5 cm from the beak and 6 to 8 per 5 mm at the commissure). the dorsal median septum is thick, particularly in its posterior part and becomes relatively thin anteriorly. it is long, reaching the mid-length of the shell. the dental plates are short, thin and vertical. the ventral muscle field is poorly impressed and marked by a few, very low radial ridges. discussion this species is close to the former one but differs in its more quadratic outline and its smaller size, although it remains larger than previously known species of the genus. the ventral valve is rounded in cross section, in contrast with ladogilina sp. 1 (where it is flattened); it is also proportionally higher than in ladogilina sp. 1. furthermore, the ribs are finer and more numerous. this characteristic is reminiscent of both l. rossica and l. simensis in which the number of costae in 5 mm at 1.5 cm from the beak is around 9 to 11. ladogilina sp. 2 is very close to l. rossica in its external aspect and internal features; it differs only by its larger size. the genus ladogilina is known in russia (urals and timan), eastern iran (kerman province) and western afghanistan. all the occurrences are from the lower frasnian (asymmetricus zone). order atrypida rzhonsnitskaja, 1960 suborder atrypidina moore, 1952 superfamily atrypoidea gill, 1871 family atrypidae gill, 1871 subgenus spinatrypa (spinatrypa) stainbrook, 1951 type species: atrypa hystrix var. occidentalis hall, 1858, p. 515. table 2 measurements (in mm) of the two species of ladogilina from the kozan section, near kilgen lake, se turkey. sample l w hd hv nc per 5 mm at nc per 5 mm at 1.5 cm from beak commissure ladogilina sp. 1 lpb 12426 38 39 20 8 8 4 lpb 12428a ≈30 ≈40 15 7 8 5 lpb 12428b 32 34 20 9 8 5 ladogilina sp. 2 lpb 12429a 28 31 12 11 11 6 lpb 12429b 28 35 14 10 12 7 7gourvennec: upper devonian brachiopods from eastern taurus (turkey) spinatrypa (spinatrypa) sp. e.g. s. longispina (rigaux, 1872) pl. 1, figs. 14–18; table 3 material eight complete specimens and some separate valves; lpb 12404 – lpb 12409. kozan section, levels pk 66a, b, c, d. description shell equibiconvex in juvenile growth stages becoming strongly dorsi–biconvex in adult stages (means of dorsal and ventral h respectively 6.9 and 4 mm – table 3), slightly wider than long (means: l=19.6 mm; w=21.4 mm) with a hinge line shorter than the maximum width. sulcus and fold absent, only indicated by a slight ondulation of the anterior commissure in adult specimens. ventral valve regularly convex; sulcus lacking in juveniles, becoming slightly developed in the immediate vicinity of the anterior commissure in adults. tongue very low and wide (exceeding 1/2 of shell width). a single gerontic specimen shows a relatively well defined sulcus and tongue. umbo feebly prominent with a wide submesothyrid foramen. interarea not developed. dorsal valve more convex than the ventral one, regularly postero–anteriorly curved. in transverse section, the valve is strongly convex in its median part, becoming concave in its postero–lateral extremities. the fold is absent. the ornament consists of coarse ribs (about 7 ribs per 10 mm near the commissure) increasing in number by dichotomy and intercalation. the growth lamellae are long (1 to 2 mm), and their anterior edge is sharply erect (with an angle reaching or exceeding 45°). they are covered with fine concentric growth lines (about 15 per mm). spines are not preserved in situ, but some remains were observed in the sediment covering the external surface of one shell. internal features unknown. discussion from the general shape, ornament (ribs and growth lines) and despite the lack of information about its internal morphology, this form is undoubtedly related to the genus spinatrypa stainbrook, 1951. given the relative convexity of the valves (shell rather dorsibiconvex) this form belongs to the subgenus s. (spinatrypa). among the numerous species assigned to the genus, this one is very close to s. longispina (rigaux, 1872) and differs only by its smaller size. the s. aspera group and s. curvirostra copper, 1967 have stronger, wider and less numerous ribs (4 ribs per 10 mm at the commissure). the adult/gerontic specimens of the present species show some similarities with atrypa nefedovae ljaschenko, 1950 in their strongly dorsiconvex profile, but differ by their smaller size and less numerous, coarser ribs. the only ascertained occurrence of s. longispina is in the upper part of the ferques formation (boulonnais, n. france), in the triangularis zone (frasnian). after godefroid (1988), the other mentioned occurrences (belgium and germany) are dubious or erroneous. order spiriferida waagen, 1883 suborder spiriferidina waagen, 1883 superfamily cyrtospiriferoidea termier & termier, 1949 family cyrtospiriferidae termier & termier, 1949 genus cyrtospirifer nalivkin, 1924 (in frederiks) type species: spirifer verneuili murchison, 1840, p. 252. cyrtospirifer sp. aff. c. kermanensis brice, 1999 pl. 2, figs. 19–23 material nine more or less complete specimens and 3 ventral valves; lpb 12412 – lpb 12417a. kozan section, levels pk66 a to e. table 3 measurements (in mm) of spinatrypa sp. cf. s. longispina (rigaux, 1872) from the kozan section, near kilgen lake, se turkey. sample l w hd hv nc (distance from the beak in mm) (5) (10) (15) (20) (25) (40) lpb 12404a 21.5 25.5 7.5 6.2 19 25 — — 33 — lpb 12406a 22 22 7.9 3.5 14? 22? ≈30 ≈36 — — lpb 12406b 14 15.5 4.6 3 ≈18 ≈30 30 — — — lpb 12407a 18.5 21.5 3.5 ≈14 ≈20 27 — — — lpb 12407b ≈11.5 ≈13 4 2.5 ≈20 ≈22 — — — — lpb 12407c 29.5 31.5 8.9 ≈7 18 22 — ≈32 50? — lpb 12407d (gerontic) 35.5 36.3 20 ≈5 16 24 28 36? 40? >50 lpb 12408a 12 13 3.5 2 14 21 24 — — — lpb 12408b 12 14.5 2.5 2.5 24 ≈40 — — — — means 19.6 21.4 6.9 4 ≈17 ≈25 ≈28 ≈35 ≈41 — 8 geologia croatica 59/1 description shell small (means: l=12 mm; lt=16 mm; w=22.3 mm without mucros), transverse with subtrapezoidal outline and slightly sinusoidal lateral commissures. the ventral valve is higher than the dorsal one (means: hd=5.2 mm; hv=7.5 mm). the shell is mucronate and the maximum width is thus located at the hinge line. shells with preserved mucros would probably reach a total width of 30 mm. when the mucros are broken, the cardinal extremities are subangular. the ventral interarea is low, apsacline, flat on its greater height, becoming abruptly curved in its upper part. it is clearly delimited (sharp angles at the transition to the flanks) with subparallel edges, longitudinally and vertically striated, with finer vertical striation. the delthyrium is triangular and bounded by high, rarely preserved deltidial plates. the beak is strong, overhanging on the area, obscuring the top of the delthyrium in posterior view. the sulcus is deep, wide (~1/3 w at the anterior margin), and easily delimited by ribs stronger than any adjacent ones. it forms a wide open v-shaped or widely rounded section. the fold is variably expressed, generally low, occasionally not protruding over the flanks, rounded in section. it is always clearly delimited by grooves, obviously deeper than adjacent ones. the tongue is rounded, variably developed, generally low. the entire shell is ribbed. the ribs on the sulcus/fold are narrower than those on the flanks, particularly in the vicinity of the anterior commissure. the ribs are simple on the flanks (about 20 on each flank), the postero– lateral ones, near mucros, being very faint and poorly expressed. their number increases by dichotomy (or intercalation?) on the sulcus/fold. these dichotomies/ intercalations occur relatively late (on the anterior half of the shell). there are generally 11 ribs (extremes: 10 and 12) on the sulcus/fold. the micro-ornament consists of fine, closely spaced concentric growth lines (about 7 per mm) and very fine radial capillae bearing densely distributed spine bases. interior: the apical part of the shell is variably thickened. the dental plates are long (1/3 l), divergent, almost straight and extrasinal. a well developed delthyrial plate is present. ctenophoridium present; crural plates apparently lacking or obsolescent. the remaining internal structures have not been observed, due to recrystallization of the shells. discussion the finely costate fold and sulcus, and the wide interarea with acute angles are consistent with assignment to the cyrtospiriferinae. cyrtospirifer nalivkin in frederiks (1924) seems to be the best classification for this species although most of the representatives of this genus show a high, triangular interarea, which is not the case here. the general aspect of our species also recalls geminisulcispirifer sartenaer, 1982, but the latter has a characteristic median groove on the fold, intrasinal dental plates and bifurcations on lateral ribs. some specimens of sinospirifer sinensis grabau, 1931, particularly those with low interarea, are similar to our species but their mucros are basally wider, their sulcus shallower, the beak less curved and the number of lateral ribs is greater. finally the most similar species is cyrtospirifer kermanensis brice, 1999, which differs from our species in its shallower, not so sharply limited sulcus and a generally subquadratic outline. c. archiaci (murchison, 1840) has a similar number of ribs, grooves bounding the fold and fine mucros, but it is more globose and elongate, with a subquadratic outline. c. disjunctus (sowerby, 1840) often considered as a synonym of c. verneuili (murchison, 1840), shows fine mucros similar to those of our species, a low ventral interarea with subparallel edges and a fold clearly delimited by deep grooves, but it is much larger with a subquadratic outline. c. echinosus ljaschenko, 1958, is a transverse form with deep fold-bounding grooves, but its mucros are poorly developed, its ribs more numerous (on both flanks and sulcus) and its ventral interarea high and rather triangular. another species, c. poljanicus ljaschenko, 1954 in ljaschenko (1959) has fine mucros but a shallower, poorly delimited sulcus and corresponding fold. c. kermanensis has been described from the frasnian of iran. cyrtospirifer sp. cf. c. verneuili (murchison, 1840) pl. 2, figs. 5–7 material two complete, crushed specimens and 1 incomplete ventral valve; lpb 12417c and lpb 12425. kozan section, levels pk66 a and e. description these poorly preserved specimens are ventribiconvex, relatively large (maximum: l=27 mm, w=40 mm, h=24 mm) with a subquadrangular outline, wider than eodmitria sp. (see description below). the ventral interarea is low (possibly owing to distortion) with a poorly prominent, more or less incurved beak. cardinal extremities are acute with incipient mucronation. the sulcus and fold are clearly delimited but very shallow/low, almost inconsistent, even in the proximity of the anterior commissure where the tongue is rather low. the sulcus has a flat v-shaped section; the fold has a rounded one. the ornament consists of very fine ribs over the entire shell. there are about 20 ribs on the fold/sulcus, where they increase in number by intercalation, and about 35 ribs on each flank on the larger specimen. they are finer than in c. sp. aff. c. kermanensis (see above) and similar in size to those of eodmitria sp. (see below), but not flattened on top. the interior is unknown. 9gourvennec: upper devonian brachiopods from eastern taurus (turkey) discussion these specimens are assigned to cyrtospirifer but owing to their poor preservation, a specific assignment remains uncertain. they differ from c. sp. aff. c. kermanensis by their larger size, poorly developed fold and sulcus, fine ribbing and ventral interarea lacking subparallel edges. they differ from eodmitria sp. by their transverse outline, more or less mucronate extremities and relatively coarser, not flattened ribs, but they show some affinities with some unpublished specimens of eodmitria sp. from the lower frasnian of ferques (boulonnais, france) presently under investigation (brice, pers. comm., 2004). genus eodmitria brice, 1982 type species: eodmitria supradisjuncta boloniensis brice, 1982, p. 578. eodmitria sp. pl. 2, figs. 8–18; table 4 material 12 almost complete specimens and 1 isolated ventral valve; lpb 12417b – lpb 12424. kozan section, levels pk66 a and c. description shell medium to large (means: l=24.8 mm; w=30.4 mm), slightly inequivalve (means: hd=8.8 mm; hv=11.9 mm) (table 4), with variable outline: subquadratic weakly elongated, rarely slightly transverse (in adult stage). the maximum width is located around the midlength. the lateral commissures are widely rounded, sometimes becoming slightly concave near the cardinal extremities. the hinge line is very short (mean: wh=19.1 mm), clearly shorter than the maximum width. cardinal extremities subangular (widely obtuse angle) with traces of weak mucronation in some specimens. the ventral interarea is triangular, occasionally abruptly interrupted distally. it is well delimited, short, relatively high, curved and apsacline, with strong vertical striae. the delthyrium is triangular, lined by apparently low deltidial plates and deltidial slots. the beak is prominent, recurved on the interarea. sulcus and fold very weak, becoming somewhat better expressed near the anterior commissure where a low, rounded tongue is developed. the sulcus is poorly delimited, the fold better delimited by two lateral grooves deeper and larger than adjacent ones. at the anterior margin, their width reaches or exceeds half of the maximum width (mean ws=14.3 mm). in transverse section, the sulcus is widely rounded or slightly subangular, particularly in the juvenile stages. the entire shell is ribbed. the ribs are rounded with a flattened, or even depressed top, and separated by narrow, rounded to subangular interspaces. the ribs are generally simple on the flanks, with a few exceptions, the distal ones being very faint. their number lies between 30 and 38 per flank. dichotomies, more rarely trichotomies, occur on the sulcus and fold, where the ribs are finer than the lateral ones. there are 13 to 27 ribs at the anterior edge of the sulcus/fold (mean=20.9). the microornament consists of very close prominent growth lines (4 to 5 per mm), with irregularly distributed spine bases or pustules. ventral interior: the dental plates are thin, straight, relatively long (about 1/4 l), slightly internally convex in section. the delthyrial plate is thin, and relatively long. there is no apical thickening of the shell. muscle prints were not observed. table 4 measurements (in mm) of eodmitria sp. from the kozan section, near kilgen lake, se turkey. sample l lt w wh ws hd hv ncf ncs lpb 12418a 20 25 25 15 ≈10 6 10 ≈30 ≈13 lpb 12418b 23 28 27 18.5 14 9 15 30 20 lpb 12418c 20.5 27 26 12.5 ≈12 7 10 33 18 lpb 12419a 24.5 30.5 31 22 14 10 12 34 ≈20 lpb 12419b 26.5 32.5 32.5 27 ≈14 ≈7? ≈12 — — lpb 12421a 21 28.5 ≈31 21 ≈14 — ≈10 32 ≈21 lpb 12424a — — 31.5 16 — 10 11 35 20–22 lpb 12424b 34 39.5 38.5 23.5 19 11 13 37–38 ≈27 lpb 12424c 28 34 33 ≈18 15 10 13 ≈30 23 lpb 12424d 27 32 ≈34 21 15 9 13 37 20–21 lpb 12424e 28 34 34 19 16.5 9 14 >30 21–22 lpb 12424f 20.5 25.5 24.5 17 ≈12 8 10 33 19 lpb 12424g 24.5 31.5 ≈27 ≈18 ≈16 ≈9 ≈12 31 ≈26 means 24.8 30.7 30.4 19.1 14.3 8.8 11.9 ≈33 ≈21 10 geologia croatica 59/1 dorsal interior: the cardinal process is striated. the crural bases are long. discussion the general outline of the shell, the weak, ill-defined sulcus and fold, the number of ribs and their shape, the presence of a well developed delthyrial plate, and the presence of crural plates, etc. indicate that this species belongs to eodmitria brice, 1982. in the closely related genus dichospirifer brice, 1971, the ribs are dichotomous on the entire shell and the delthyrial plate is rudimentary. the closely related genus uchtospirifer ljaschenko, 1957 possesses a well developed delthyrial cover and the sulcus and fold are clearly marked. in the original diagnosis, brice (1982 – p. 575) indicates that the shell is always mucronate in eodmitria. nevertheless, some species assigned to the genus since its erection show only a very slight mucronation. despite its ressemblance to several species of the genus, the nomenclature of this species remains open because no known species possess this combination of characters. eodmitria supradisjuncta (obrutchev, 1917) differs from eodmitria sp. in its thick dental and delthyrial plates and a thickened apical region. the subspecies e. supradisjuncta boloniensis brice, 1982 (type-species of the genus) also shows an apical thickening and has less numerous lateral ribs, a more transverse outline and a more pronounced tendency to mucronation. e.? seminoi (verneuil, 1850) is also apically thickened, has intrato subsinal dental plates and lacks crural bases. e. oblivialis sartenaer, 1982 is larger, with a generally longer hinge line, and has stronger, less numerous ribs. it is possible that this species could be the same as that cited by tchihatcheff (1854) in the region of feké (anti-taurus) under the name spirifer seminoi verneuil. the genus eodmitria is known from the lower frasnian of western europe (asymmetricus zone) and the middle frasnian from the russian platform (timanicus and triangularis zones). suborder delthyridina ivanova, 1972 superfamily delthyridoidea phillips, 1841 family mucrospiriferidae boucot, 1959 genus eleutherokomma crickmay, 1950 type species: eleutherokomma hamiltoni crickmay, 1950, p. 220. eleutherokomma hamiltoni? crickmay, 1950 pl. 2, figs. 1–4 material three ventral valves and one interior of a ventral valve; lpb 12410 – lpb 12411. kozan section, levels pk66 b and c. description transverse shell with subtrapezoidal outline, laterally developing very long mucros. the largest shell is 60 mm wide including mucros (that is about 30 mm without mucros) and 12 mm long. the area is relatively low, strongly apsacline, separated from the flanks by angular edges. the beak is barely prominent. the triangular delthyrium is bordered by low deltidial plates that probably join (?) under the umbo. the sulcus is wide (ws=7.5 mm on the above mentioned specimen), shallow, somewhat flared with a rounded section, and bears a faint median ridge. the ornament consists of 7 lateral rounded ribs per flank, separated by narrow subangular interspaces. the external pair is very faint but the internal pair (bounding sulcus) is clearly stronger than the others. microornament consists of wavy growth lamellae, the density of which increases anteriorly, and that bear very fine concentric growth lines (8 per mm). ventral interior with strong apical thickening embedding the apical structures: delthyrial ridge (rather than true delthyrial plate) and obsolescent dental plates. teeth short, small, elliptical in outline. no trace of muscle scars observed. dorsal valve unknown. discussion after the general aspect of the shell, and particularly the long mucronations, this species can undoubtedly be assigned to eleutherokomma crickmay, 1950. the closest species is e. hamiltoni crickmay, 1950, which presents a comparable number of ribs, with sulcus bounding costae stronger than the lateral ones, and very long mucros. it differs in the presence of short dental plates that are partly free and thus visible, due to a less significant shell apical thickening. this variation could result from different environmental conditions. the other species of eleutherokomma with few lateral ribs as in this species, have either short mucros or they are absent. e. hamiltoni is known from the lower frasnian of canada (lower asymmetricus zone). 3. conclusions despite the fact that the nomenclature of many species described here remains open, due to the few specimens at hand, an estimation of the age can be done with reasonable certainty. at the generic level, this assemblage indicates a late devonian age: 4 genera have a middle– upper devonian distribution, 2 are upper devonian and 3 are frasnian (douvillina, eodmitria and ladogilina), one of them (ladogilina) being restricted to the lower frasnian. otherwise, the presence of spinatrypa precludes a famennian age. this leaves no doubt about a frasnian age and an early frasnian age is probable, 11gourvennec: upper devonian brachiopods from eastern taurus (turkey) although cyphoterorhynchus is mentioned from the middle–upper frasnian. this is reinforced by an examination at the species level: even if the specific assignments are not definitely stated, all the specific proximities recognized here are with frasnian species (e.g. r. elburzensis, c. koraghensis, s. longispina, e. hamiltoni, c. kermanensis, etc.). the association shows close affinities with those described from iran and afghanistan (brice, 1971, 1999) and also from the russian platform, timan and volgo–uralian areas (ljaschenko, 1959, 1973). several genera are common to these regions, and it is probable that the differences and/or uncertainties at the specific level could be clarified after complementary sampling in turkey. it is clear that our material is insufficient for a detailed study, but the obvious similarities in the fossil assemblages are troubling if not significant, particularly if we consider some genera with relatively restricted geographic distributions (e.g. eleutherokomma and ladogilina). resemblances also occur at the morphological level, since several taxa from these different regions share peculiar shell “habitus”: highly developed, globose ventral valves (ladogia, spinatrypa), sub-cuboid shells (ripidiorhynchus, cyphoterorhynchus variants reminiscent of hypothyridina) or the contrasted very short/very wide hinged spiriferids (eodmitria vs. eleutherokomma). this morphologic analogy is probably related to similar environmental conditions. the faunal similarities between iran, afghanistan, pakistan and armenia during the upper devonian have been already underlined by several authors (e.g. brock & yazdi, 2000). the devonian turkish fauna indicates that the taurids (at least the eastern part of the taurids) should be included in this group of regions constituting the so-called “cimmerian belt”, a suite of terranes located along the north gondwanan margin. furthermore, the presence of eleutherokomma, also known in iran, mauritania (racheboeuf et al., 2004), northern france and eastern canada, reinforces the faunal evidence for a narrow oceanic separation between north gondwana and euramerica at this time, contrary to some reconstructions based mainly on palaeomagnetic data. acknowledgements many thanks to o. monod (university of orléans, france) who sampled and placed this material at my disposal. i am also grateful to the reviewers, u. jansen and j. sremac, for their helpful comments on the manuscript and j. robson for the language review. 4. references abramian, m.s. (1957): brakhiopody verkhnefamenskikh i etrenskikh otlojenii iugo-zapadnoi armenii [brachiopods of the upper famennian and etroeungt deposits of sw armenia – in russian].– izdateltsvo akademia nauk armianskoi ssr, erevan, 142 p. brice, d. (1971): etude paléontologique et stratigraphique du dévonien de l’afghanistan [paleontological and stratigraphical study of the devonian of afghanistan – in french].– notes et mémoires sur le moyen orient, 11, 364 p. brice, d. (1982): eodmitria, genre nouveau de brachiopode cyrtospiriferidae du frasnien inférieur et moyen [eodmitria, a new cyrtospiriferidae brachiopod genus from the lower and middle frasnian – in french].– geobios, 15, 575–581. brice, d. (1999): new upper devonian rhynchonellid and spiriferid brachiopod taxa from eastern iran (kerman province) and central iran (soh region).– annales de la sociéte géologique du nord, 7, 2ième série, 71–78. brock, g.a. & yazdi, m. (2000): palaeogeographic affinities of late devonian brachiopods from iran.– in: mawson, r., talent, j.a. &. long, j.a. (eds.): mid-palaeozoic biota and biogeography. records of the western australian museum, supplement 58, 321–334. brousmiche, c. (1973): révision des productellidae (brachiopodes) du dévonien de ferques (boulonnais, france) [revision of the productellidae (brachiopods) from the devonian of ferques – in french].– annales de la société géologique du nord, 92/2, 117–136. buch, l. von. (1834): über terebrateln, mit einem versuch, sie zu classificiren und zu beschreiben [about the terebratules, with a tentative classification and description – in german].– abhandlungen der königlichen akademie der wissenschaften zu berlin, 1833, 21–144. copper, p. (1967): spinatrypa and spinatrypina (devonian brachiopoda).– palaeontology, 10, 489–523. crickmay, c.h. (1950): some devonian spiriferidae from alberta.– journal of paleontology, 24, 219–225. ellern, s.s., ivanov, e.e. & kurbanov, f.y. (1955): brakhiopody devona tatarskoi assr [devonian brachiopods of the tatar assr – in russian].– in: krylova, a.k. (ed.): brakhiopody devona volgo–uralskoi oblasti. vnigri. trudy, 88, 107–145. frederiks, g.n. (1924): paleontologicheskie ztoudy. 2: o verkhne-kamennougolnykh spiriferidak ourala [paleontological studies. 2. on upper carboniferous spiriferids from urals – in russian].– geologicheskogo komiteta, izvestiya, 38 (1919), 295–324. gaetani, m. (1965): brachiopods and molluscs from geirud formation, member a (upper devonian and tournaisian).– rivista italiana de paleontologia, 71, 679–770. gedik, i. (1988). a paleogeographic approach to the devonian of turkey.– in: mc millan, n.j., embry, a.f. & glass, d.j. (eds.): devonian of the world. memoirs of the canadian society of petroleum geologists, 14/1, 557–567. godefroid, j. (1988): brachiopodes atrypida du dévonien de ferques (boulonnais – france) [brachiopods atrypida from the devonian of ferques (boulonnais, france) – in french].– in: brice, d. (ed.): le dévonien de ferques. bas-boulonnais (n. france). biostratigraphie du paléozoïque, 7, 403–432. 12 geologia croatica 59/1 gosselet, j. (1887): note sur quelques rhynchonelles du terrain dévonique supérieur [note on some rhynchonellas from the upper devonian beds – in french].– annales de la sociéte géologique du nord, 14, 188–221. grabau, a.w. (1931): devonian brachiopoda of china. 1 – devonian brachiopoda from yunnan and other districts in south china.– palaeontologia sinica, serie b, 3/3, 1–752. hall, j. (1858): palaeontology of iowa.– in: hall, j. & whitney, j.d. (eds): report of the geological survey of the state of iowa, embracing the results of investigations made during portions of the years 1855, 56 and 57. vol. 1/2, 473–724, des moines. hall, j. (1867): palaeontology of new york.– vol. 4 (1), containing descriptions and figures of the fossil brachiopoda of the upper helderberg, hamilton, portage and chemung groups. 428 p., new york. lazarev, s.s. (1989): systema devonskikh brakhiopod podotriada strophalosiidina [systematics of devonian brachiopods of strophalosiidina suborder – in russian].– paleontologicheskii zhurnal, 1989, 2, 27–39. ljaschenko, a.i. (1950): brakhiopody poddomanikovikh otlojenii iujnogo timana i ik stratigraficheskoi znatchenie [brachiopods of the sub-domanik deposits of south timan and their stratigraphic significance – in russian].– fondia ign sssr (unavailable). ljaschenko, a.i. (1957): novyi rod devonskikh brakhiopod: uchtospirifer [a new genus of devonian brachiopods: uchtospirifer – in russian].– akademiia nauk sssr, doklady, 117/5, 885–888. ljaschenko, a.i. (1958): brakhiopody nijnefranskikh otlojenii tsentralnoi chasti russkoi platformi [brachiopods of lower frasnian deposits of the central part of the russian platform – in russian].– vnigrni, gosgeolizdat, trudy, 9, 105–157. ljaschenko, a.i. (1959): atlas brakhiopod i stratigraphiia devonskikh otlojenii tsentralnikh oblastei russkoi platformi [atlas of brachiopods and stratigraphy of the devonian deposits of the central region of the russian platform – in russian].– ministerstvo geologii i okrania nedr sssr (vnigii), 451 p. ljaschenko, a.i. (1973): brakhiopody i stratigraphiia nijnefranskikh otlojenii iujnogo timana i volgo–uralskoi neftegazonosnoi provintsii [brachiopods and stratigraphy of lower frasnian deposits of the south timan and volga–ural oil–gas bearing province – in russian].– ministerstvo geologii sssr, trudy, 134, 1–279. murchison, r.i. (1840): description de quelques unes des coquilles fossiles les plus abondantes dans les couches dévoniennes du bas boulonnais [description of some more numerous fossil shells in the devonian layers of the bas boulonnais – in french].– bulletin de la société géologique de france, 1ière série, 11, 250–257. nalivkin, d.v. (1937): brakhiopody verkhnego i srednego devona i nijnego karbona severo–vostochnogo kazakhstana [brachiopoda of the upper and middle devonian and lower carboniferous of northeastern kazakhstan – in russian].– tsentral’nyi nauchno–issledovatel’skii geologo–razvedochnyi institut (tsnigri), trudy, 99, 1–200. obrutchev, s.v. (1917): voronejskii devon i gruppa spirifer verneuili murch [the devonian of voronej and the group of spirifer verneuili murch – in russian].– zapiski geologicheskogo otdelenii obchtchestva liobitelei– estestvoznaia antropologii i etnografii, 5, 21–60. oehlert, d.p. (1887): appendice: brachiopodes; notions sur l’anatomie et la physiologie des brachiopodes [appendice: brachiopods; elements on the anatomy and physiology of brachiopods – in french].– in: fischer, h. (ed.): manuel de conchyliologie et de paléontologie conchyliologique ou histoire naturelle des mollusques vivants et fossiles, 11, 1189–1334. racheboeuf, p.r., gourvennec, r., deynoux, m. & brice, d. (2004): the devonian of the hodh area (islamic republic of mauritania): paleontology, stratigraphy and paleobiogeographic implications.– journal of paleontology, 78, 98–110. reed, f.r.c. (1922): devonian fossils from chitral and the pamirs.– memoirs of the geological survey of india, paleontologia indica, 6/2, 1–134. rigaux, e. (1872): notes pour servir à la géologie du boulonnais. 1. description de quelques brachiopodes du terrain dévonien de ferques [notes to serve about the geology of the boulonnais. 1. description of some brachiopods from the devonian beds of ferques – in french].– mémoires de la société académique de l’arrondissement de boulogne sur mer, 5, 16 p. sartenaer, p. (1961): etude nouvelle, en deux parties, du genre camarotoechia hall & clarke, 1893. deuxième partie: cupularostrum recticostatum n.gen., n.sp. [new study, in two parts, of the genus camarotoechia hall and clarke, 1893. second part: cupularostrum recticostatum n.gen., n.sp. – in french].– bulletin de l’institut royal des sciences naturelles de belgique, 37/25, 1–15. sartenaer, p. (1965): rhynchonelloidea de shogran et kuragh (chitral) [rhynchonelloidea from shogran et kuragh (chitral) – in french].– italian expeditions to the karakorum (k2) and hindu kush, scientific reports, 4, paleontology, 1, 55–66. brill, leiden. sartenaer, p. (1966a): ripidiorhynchus, nouveau genre de brachiopode rhynchonellide du frasnien [ripidiorhynchus, a new frasnian rhynchonellid brachiopod genus – in french].– bulletin de l’institut royal des sciences naturelles de belgique, 42/30, 1–15. sartenaer, p. (1966b): frasnian rhynchonellids from the ozbak–kuh and tabas regions (east iran).– geological survey of iran, reports, 6, 25–53. sartenaer, p. (1982): the presence and significance of spirifer bisinus, s. malaisi, s. supradisjunctus, and s. seminoi in early frasnian beds of western europe.– in: sartenaer, p. (ed.): papers on the frasnian–givetian boundary, 122–196. sokolskaja, a.n. (1948): evolutsiia roda productella hall i smezhnykh s nim form v paleozoe podmoskovnoi kotloviny [evolution of the genus productella hall and related forms in the paleozoic of the moscow region – in russian].– akademiia nauk sssr, paleontologicheskii institut, trudy, 14/3, 1–168. sowerby, j. de c. (1840): on the physical structure and older stratified deposits of devonshire.– in: sedgwick, 13gourvennec: upper devonian brachiopods from eastern taurus (turkey) a. & murchison, r.i. (eds.): on the distribution and classification of the older or paleozoic deposits of the north of germany and belgium and their comparison with formations of the same age in british isles. transactions of the geological society of london, 2nd series, 5/3, 633–703. stainbrook, m.a. (1943): strophomenacea of the cedar valley limestone of iowa.– journal of paleontology, 17, 39–59. stainbrook, m.a. (1951): substitution for the pre-occupied brachiopod name hystricina.– journal of the washington academy of sciences, 41, 196. tchihatcheff, p. (1854): dépôts paléozoïques de la cappadoce et du bosphore [paleozoic deposits of the cappadocia and bosphorus – in french].– bulletin de la société géologique de france, 2ième série, 11, 402–416. verneuil, e. de (1850): notice sur la collection de roches recueillie en asie par feu hommaire de hell, et sur les divers travaux exécutés pendant le cours de son voyage (in: viquesnel, m.) [notice on the rock collection sampled in asia by the late hommaire de hell, and on various studies realized during the course of his trip – in french].– bulletin de la société géologique de france, 2ième série, 7, 491–514. manuscript received april 6, 2005. revised manuscript accepted november 11, 2005. 14 geologia croatica 59/1 plate 1 fig. 1 douvillina sp. level pk66c. interior of ventral valve, x2, lpb 12400. figs. 2–5 productella sp. cf. p. subaculeata (murchison, 1840). level pk66c. dorsal, ventral, posterior and lateral views, x1.5, lpb 12402. figs. 6–9 ladogilina sp. 1. level pk66a. ventral, dorsal, posterior and lateral views, x1, lpb 12426. figs. 10–13 ripidiorhynchus sp. cf. r. elburzensis (gaetani, 1965). level pk66b. lateral, dorsal, anterior and ventral views, x1.5, lpb 12403. figs. 14–18 spinatrypa (spinatrypa) sp. e.g. s. longispina (rigaux, 1872). level pk66c. dorsal, ventral, anterior, posterior and lateral views, x1, lpb 12407. figs. 19–23 cyphoterorhynchus koraghensis (reed, 1922). level pk66c. dorsal, ventral, anterior, posterior and lateral views, x1, lpb 12438. figs. 24–28 cyphoterorhynchus arpaensis (abramian, 1957). level pk66c. dorsal, ventral, anterior, posterior and lateral views, x1, lpb 12435. figs. 29–33 ladogilina sp. 2 cf. l. rossica ljaschenko, 1973. level pk66e. 29–32: dorsal, ventral, anterior and posterior views, x1, lpb 12429a; 33: posterior view of internal mould, x1.5, lpb 12429d. all specimens are from the kozan section (kilgen lake, eastern taurus, central turkey). 15gourvennec plate 1 1 2 3 4 5 6 7 8 9 10 11 12 14 15 13 16 18 17 23 19 20 21 24 25 26 29 30 31 27 33 32 28 22 16 geologia croatica 59/1 plate 2 figs. 1–4 eleutherokomma hamiltoni? crickmay, 1950. level pk66c. 1–3: ventral, anterior and lateral views, lpb 12411a; 4: interior of ventral valve, lpb 12411c. figs. 5–7 cyrtospirifer sp. cf. c.verneuili (murchison, 1840). level pk66e. 5–6: dorsal and ventral views; 7: microornament (x10), lpb 12417c. figs. 8–12 eodmitria sp. level pk66a. dorsal, ventral, anterior, posterior and lateral views, lpb 12418b. fig. 13 eodmitria sp. level pk66a. microornament (x10). lpb 12422. figs. 14–18 eodmitria sp. level pk66c. anterior, dorsal, ventral, posterior and lateral views, lpb 12424. figs. 19–23 cyrtospirifer sp. aff. c. kermanensis brice, 1999. level pk66c. dorsal, lateral, ventral, anterior and posterior views, lpb 12415. all specimens are from the kozan section (kilgen lake, eastern taurus, central turkey) and x1.5, unless otherwise indicated. 17gourvennec plate 2 1 2 3 4 8 7 65 9 10 11 12 13 14 15 16 17 19 20 21 18 22 23 18 geologia croatica 59/1 lackovic.indd 213 lacković et al.: evolution of the veternica cave (medvednica mountain, croatia) drainage system... � ab stra ct detailed fi eld examination, u-th age dating, and stable isotope analysis of veternica fl owstone and shelfstone deposits have been employed in order to unravel details about the geological history of veternica cave (medvednica mountain, croatia). the study was carried out in the hydrologically inactive part of the main cave channel, which is developed mainly along the unconformity between triassic dolostone and miocene limestone. for 180 m from the cave entrance, (located at 320 metres above sea level (asl)), the morphology of the main channel refl ects exclusively phreatic conditions in the cave until the end of its hydrological activity. from 180 to 390 m, the phreatic channel has a secondary vadose entrenchment in the bottom part as marked by massive fl owstones at elevations from 306 to 313.5 m asl. from 390 m farther inside the cave (in the upstream direction), the main channel has a tall, narrow cross-section and is of mainly vadose origin. in this part of the cave shelfstone precipitates are observed at 9 different levels ranging from 318.8 to 320.2 m asl, indicating the water palaeolevels in the cave. u-th dating revealed the age of the highest shelfstone (320.2 m asl) of ~380 kyrs bp, and the age of the lowermost analyzed shelfstone (318.9 m asl) of ~245 kyrs bp. dating of fl owstone deposits, located below the shelfstone level, revealed their formation from ~235 to 205 kyrs bp. a relatively rapid water table lowering and transition from phreatic to vadose conditions occurred within the cave, from ~245 to 235 ka bp, between formation of the youngest shelfstone (representing phreatic conditions below their level) and the oldest fl owstone (marking the beginning of vadose conditions). the results provide unique new information about veternica cave genesis and geomorphologic evolution of the medvednica mountain area. keywords: speleogenesis, shelfstone, fl owstone, u-th dating, water table lowering, veternica cave, croatia evolution of the veternica cave (medvednica mountain, croatia) drainage system: insights from the distribution and dating of cave deposits � damir lacković1, bosiljka glumac2, yemane asmerom3 & andrej stroj4 1croatian natural history museum, zagreb, croatia; (damir.lackovic@hpm.hr) 2department of geosciences, smith college, northampton, massachusetts 01063, usa; (bglumac@smith.edu) 3deptartment of earth & planetary sciences, university of new mexico, albuquerque, new mexico, usa; (asmerom@unm.edu) 4croatian geological survey, zagreb, croatia; (andrej.stroj@hgi-cgs.hr) doi: 104154/gc.2011.18 geologia croatica 64/3 213–221 6 figs. 2 tabs. zagreb 2011 geologia croaticageologia croatica 1. introduction veternica cave is located in the southwestern part of the medvednica mountain in the vicinity of zagreb, the capital of croatia (fig. 1). the cave is located in a small isolated karst area, separated from the main dinaric karst region. the cave has been declared a geomorphologic natural monument and is protected within the medvednica nature park. veternica was discovered in the 19th century (gorjanovićkramberger, 1899), and is named after a local term for wind (veter or vjetar; i.e. the wind cave), because of the constant air circulation through the cave channels that can be felt near the cave entrance. the fi rst detailed speleological and geological investigations of the veternica cave were geologia croatica 64/3geologia croatica 214 performed by poljak (1934), and later on by malez (1965), čepelak (1977), panuška & marjanac (1977), sutlović (1991), marjanac et al. (2005), and marjanac (2007), among others. malez (1965) (a palaeontologist), conducted systematic research on the cave entrance sediments, during which the natural entrance was widened from 0.45 x 0.29 m (hirc, 1903) to about 4 x 3 m. this research revealed a rich late pleistocene fauna and neanderthal artifacts (malez, 1965). more recent research by miracle & brajković (2010) provided a revision of ple istocene faunal characteristics from the veternica entrance sediments and their palaeoclimatic implications. malez (1965) gave a detailed description of clastic deposits at the cave entrance. analysis of associated fossils suggested the late pleistocene age of the deposits, ranging from the end of the riss glacial to the holocene. deposits from the deeper parts of the cave were not described in detail, but malez (1965) documented the channel morphology and made a map and cross-section of the channels up to about 2000 m from the cave entrance. malez (1965) also produced a general interpretation of the cave formation through multiple phases of its geological history. he concluded that during the oldest phase there was an active spring at the present-day cave entrance, and he described a gradual retreat of the water towards the cave interior to its current sink. nowadays, there is a great public interest in veternica. it is the 6th longest cave in croatia with a total cave channel length of 7128 m (croatian speleological server, 2011), and is easily accessible from zagreb, the lar gest city in croatia. the fi rst 380 m of the cave are open for tourists and many speleological schools are held in the cave. the current study aimed at gaining detailed information about the history of the cave that could then be incorporated into tourist guides and shared with visitors, such as the nature and timing of palaeoenvironmental changes associated with a water level lowering in the karst drainage system of the cave. this information was primarily gathered through an in-depth fi eld investigation and a detailed study of the cave fl owstone and shelfstone deposits. field investigation focused on the morphology of the veternica cave conduits and associated alluvial sediments in order to determine hydrological conditions in the cave during its hydrological activity (e.g., bögli, 1980; ford & williams, 1989; palmer, 2007). phreatic conduits usually have elliptical to round cross-sections, and as they are formed by pressure fl ow, their inclination direction is not constrained by fl ow direction. vadose channels, on the other hand, are typically vertical shafts or meandering canyons formed by gravity fl ows, and consequently their inclination direction is uniform and governed by fl ow direction. multiple phase channels commonly have phreatic upper parts with vadose trenching in their lower parts (i.e., a typical “keyhole” profi le). this study also focused on the veternica cave fl owstones and shelfstones because they can provide important information for the detailed reconstruction of cave formation and its palaeoenvironments. the cave fl owstones precipitate from thin fi lms of water fl owing over subaerially exposed surfaces, and shelfstones, also known as water-table speleothems, are calcite deposits precipitated at the water surface as ledges attached to the cave walls (hill & forti, 1997). these precipitates can be very good indicators of former water levels in caves, as shown by ford et al. (1993), szabo et al. (1994), and auler & smart (2001). veternica shelfstones from the “majmunski prolaz” channel, at about 450 m from the entrance, and the “kameni slap” fl owstones in the “touristic” part of the cave about 250 m from the entrance (sample locations 1–2 and 3–5; fig. 2b), were fi rst studied by lacković and horvatinčić in 1999 (unpubl.), who collected 4 shelfstone samples and 1 sample of the “kameni slap” fl owstone for radiocarbon dating at the ruđer bošković institute in zagreb. since the resulting ages were greater than the limit of the 14c technique at that time (>35 kyrs) no further analyses were conducted. the current study refl ects renewed interest in the geological history of the veternica cave made possible through the use of the modern u-th radiometric dating method. 2. geological and hydrogeological setting unlike the rest of the medvednica mountain region where carbonate rocks are associated with siliciclastic, metamorphic and volcanic rocks, the western part of medvednica that hosts the veternica cave is made up mainly of carbonate rocks. the oldest rocks in the area are triassic dolostones, dolomitic limestones, and limestones with interbedded chert, shale and pyroclastic deposits, which are overlain by miocene dolomitic breccias and conglomerates as well as bioclastic limestones (šikić, 1995). the veternica cave passages are of varying morphology and are located mainly figure 1: location of veternica cave in the southwestern part of medvednica mountain. geologia croatica 215 lacković et al.: evolution of the veternica cave (medvednica mountain, croatia) drainage system... along the unconformable contact between triassic dolostones and miocene limestones (malez, 1965; čepelak 1977; fig. 2a). some of the passages also follow fractures in both of these deposits. the cave is part of a karst channel system that drains water from sinkholes of the “ponikve” karst polje and the surrounding karst terrain, through the subsurface to the “dubravica” spring (malez, 1963; božićević, 1976; čepelak, 1977; fig. 2a), as confi rmed by dye testing (božičević, 1976). there are 9 sinking streams that drain into veternica. two of them are located in the ponikve polje, and the rest are located west of veternica in the extension direction of the cave lateral channels (fig. 2b; čepelak, 1977; 1979). there are currently 14 active streams in the cave (čepelak, 1977). the cave entrance is located 320 m asl, and the cave channels range in elevation from 265 m asl (at the bottom of “ponor 16 m” channel; fig. 2b) to 435 m asl, yielding a total elevation difference of 170 m. the cave channels up to approximately 900 m from the cave entrance are hydrologically inactive, but their phreatic and/or vadose morphology is very well preserved owing to an absence of collapse processes and rare speleothem precipitates. from 900 m farther inside the cave, there is an active stream that ends in the “main siphon” located below the main cave channel (fig. 2b). besides this main channel, there are several generally narrower lateral side channels (e.g., “velebitaški” channel; fig. 2b). above the main cave channel with active water fl ow (approximately at 950 to 1350 m from the cave entrance), dry chambers and passages occur at higher elevation. steep side channels with vadose morphology are present below the level of the main channel in several places at 180 to 900 m from the cave entrance (e.g., “ponor 16 m”, “vele bitaški siphon” below “velebitaški” side channel, “kukušni” channel, channel towards the “main siphon”; fig. 2b). the main sinkholes of ponikve karst polje are at 470 m asl, while the present-day “main” cave siphon is at 295 m asl, and the cave water surfaces at the dubravica spring at 220 m asl (fig. 2a). 3. methods fieldwork for this study was carried out in 2008 and 2009 in the hydrologically inactive part of the main veternica cave channel. the cave shelfstone and fl owstone deposits figure 2: cross-sections of the main veternica cave passages. a) geological profi le illustrating the water drainage pattern from sinkholes along the ponikve karst polje and through the cave to the dubravica spring. b) enlarged area to show detail of the main cave passage and parts of the side channels. shelfstone (1 & 2) and fl owstone (3, 4 & 5) sampling locations are indicated. reconstructed palaeolake are also shown. note vertical exaggeration. geologia croatica 64/3geologia croatica 216 were described and documented in detail and samples for u-th age dating and stable isotope (oxygen and carbon) analyses were collected. to precisely measure the elevation of various shelfstone and fl owstone deposits, a detailed topographic survey from the cave entrance to the “main siphon” that marks the present-day water level and the contact between the vadose and phreatic zone in the cave was carried out (fig. 2b). the topographic survey was conducted using a precise compass and clinometer (suunto types) and calibrated rods. every measurement of polygonal segments was executed both forward and backward to obtain the maximum survey precision. the 234u–230th dating was done at the radiogenic isotope laboratory, the university of new mexico, usa. samples were spiked with a mixed 229th–233u–236u spike. u and th were separated using conventional anion exchange chromatography. u and th isotopes were measured using a thermo neptune multi-collector inductively coupled plasma mass spectrometer (mc-icpms) which was optimized for u-series analytical work as described by asmerom et al. (2006). 234u was measured on a secondary electron multiplier with high abundance fi lter, while the other isotopes of uranium were measured on faraday cups with amplifi ers that had mixed 1010, 1011 and 1012 ohm resistors for 233u and 236u, 235u and 238u, respectively. mass fractionation was monitored using the 236u/233u ratio, while sem/faraday gain was set using sample standard bracketing. a similar procedure was used for th isotope measurements. we used an initial 230th/232th atomic ratio of 4.4x10–6 assuming a source of th with a bulk earth 232th/238u ratio of 3.8. the age errors in table 1 refl ect analytical errors and uncertainties in the value of the initial ratio (± 50%). the laboratory u and th procedural blanks range from 10–40 pg and 5–20 pg, respectively and were not analytically signifi cant. the crm145 u isotope standard was measured with the samples obtaining the conventionally accepted δ234u value of –36.5±0.5‰ (cheng et al., 2000). samples for stable isotope analysis represent a small amount of carbonate powder collected from fl owstone and shelfstone specimens using a microdrill mounted on a binocular microscope. the fl owstone samples were mainly drilled along stratigraphic horizons that represent a series of thin laminae made up of fi nely to medium crystalline calcite. the shelfstone samples were also drilled along distinct stratigraphic horizons composed of coarse to very coarse crystalline calcite with only faint laminations visible in some specimens. all samples were heated at 400°c for one hour to remove volatile organic components. at the university of massachusetts at amherst, usa, samples were reacted with 100% anhydrous phosphoric acid (h3po4) for ten minutes and analyzed using an on-line automated carbonate preparation system (kiell iii) linked to a finnigan-mat deltaxl+ ratio mass spectrometer. standard isobaric and phosphoric acid fractionation corrections were applied to all data. internal analytical precision, monitored through daily analysis of carbonate standards, is better than or equal to 0.1‰ for both carbon and oxygen isotope values. stable isotope results are expressed as δ13c and δ18o values in ‰ relative to the vienna peedee belemnite standard (vpdb). 4. results 4.1. field investigation the fi rst part of the main veternica channel, from the cave entrance to 180 m (fig. 2a) is characterized by wide, circular to elliptical conduits with basal fi lls of clastic alluvial sediments (fig. 3b). alluvial sediments at the bottom of the cave channels have been partly dug out by cavers during early cave explorations and also later on to ease tourist access (fig. 3a). the overall channel shape and the gently undulating surface morphology of the basal alluvial sediments characterized by the absence of uniform slope direction and the lack of evidence for any vadose downcutting, all indicate the presence of phreatic or epiphreatic fl ow conditions in this part of the cave until the end of its hydrological activity. at 180 to 390 m from the cave entrance, the initially phreatic channel is characterized by secondary vadose entrenchment with a uniform downstream slope direction. this vadose entrenchment ends at the beginning of the “ponor 16 m” side channel at 180 m from the cave entrance, and the main cave channel contains fl owstone deposits at 250 m from the entrance (fig. 2b; sampling sites 3, 4 and 5). figure 3: characteristic morphology of the cave channels. a) photograph of a phreatic channel (located 75 m from the cave entrance), covered with clastic sediment in the basal part (the cut through the sediment is man made); b) sketch of a phreatic channel (located about 130 m from the cave entrance; modifi ed after malez, 1965); c) photograph of a typical vadose morphology channel (located at 550 m from the cave entrance); d) sketch of a channel with phreatic roof and tall, narrow vadose trenching morphology (located about 500 m from the cave entrance; modifi ed after malez, 1965). geologia croatica 217 lacković et al.: evolution of the veternica cave (medvednica mountain, croatia) drainage system... the third part of the main channel extends farther inside the cave (beyond 390 m), and has a tall, narrow shape with phreatic roof and vadose trenching morphology (fig. 3d). in this part of the cave, called the “majmunski prolaz” channel, at 410 to 475 m from the cave entrance there are 9 different levels of shelfstone deposits (fig 2b; sampling sites 1 and 2). the shelfstones are located along the channel sidewalls and extend towards the middle of the channel from barely noticeable 0.1 cm thick precipitates (fig. 4a) to a 105 cm long shelfstone bridging the entire width of the channel. the thickness of individual shelfstones varies from 1 to 30 mm, with an average of about 5 mm. the highest and the lowermost shelfstone levels are 20 cm above and 120 cm below the bottom of the present-day cave entrance, respectively. the lateral extent and level of the veternica shelfstones mark the position of a free surface palaeolake. according to the observed channel elevation as well as a major (vadose to phreatic) change in channel morphology, the palaeolake end ed in the downstream direction at a distance of 390 m from the cave entrance. from that point, all the way to the present entrance, the cave channels were phreatic during the existence of the palaeolake. therefore, the formation of the vadose entrenchment at 180 to 390 m as well as the fl owstone deposition at 250 m from the cave entrance both postdate the palaeolake period. in the upstream direction, the palaeolake extended to 475 m from the cave entrance (fig. 2b). from that point upstream and farther inside the cave, the channel bottom is at higher elevation than the highest observed shelfstone level. the fl owstones at the focus of this study are located approximately 250 m from the cave entrance, at an elevation of 306 to 313.5 m asl (fig. 5). they are below the entrance to a fracture-related side channel (“velebitaški”), which was the source of the palaeowater fl ow responsible for precipitation of the fl owstone known as “kameni slap” at the elevation of 306 to 312 m asl (fig. 2b: sampling sites 3 and 4; fig. 5b). the known thickness of the “kameni slap” fl owstone is 55 cm and its aerial extent is about 20 m2. the surface of the fl owstone is covered with karren and small dissolution scallops (fig. 5b), and there is a 40 cm deep erosional cut in the middle part of the fl owstone (fig. 5c). clastic deposits cover the lower part of the fl owstone and its base. excavations of these deposits during cave maintenance in 1990 revealed bones of a cave bear (ursus spelaeus; malinar & lacković, unpublished data). during the winter of 2008/2009 a detailed fi eld study of the “kameni slap” fl owstone was carried out, and specimens for u-th age dating were collected by drilling a 15 cm deep core in the deepest part of the naturally eroded cut, through the fl owstone at sampling site 3 (figs. 2b, 5d and e). the core, however, did not reach the oldest “kameni slap” fl owstone precipitate. sampling site 4 is on the surface of the fl owstone (figs. 2b and 5c). besides the “kameni slap” fl owstone, a sample from an eroded fl owstone above “kameni slap” (sampling site 5; figs. 2b and 5a), from the entrance to the “velebitaški” channel at 313.5 m asl was also collected. however, it was not possible to correlate the erosional remnants of this fl owstone to the nearby “kameni slap” fl owstone deposits. 4.2. u-th age dating shelfstone samples from the highest level, or 20 cm above the bottom of the cave entrance (sampling site 1 at 320.2 m asl; figs. 2b and 4b), and from 110 cm below the bottom of the figure 4: field photographs of the veternica cave shelfstone deposits. a) speleologist pointing at multiple shelfstone deposits, about 1 cm thick, along the sidewalls of the “majmunski prolaz” channel. b) close-up of the 1 cm thick shelfstone shown in (a) and the location of sample vet08-4 at sampling site 1 (fig. 2b). c) a ~1 cm thick shelfstone remnant and location of sample vet09-4 at sampling site 2 (fig. 2b). d) close-up photograph showing the distribution of shelfstones at 4 diff erent levels. each shelfstone is about 1 cm thick. geologia croatica 64/3geologia croatica 218 cave entrance (sampling site 2 at 318.9 m asl; figs. 2b and 4c) were dated, because the lowermost shelfstone (10 cm below the analyzed one) is relatively small and poorly preserved. the highest shelfstone gave an age of 379.8 ± 15.5 kyrs bp, and the age of the lowermost analyzed shelfstone is 244.6 ± 3.6 kyrs bp (table 1). the fl owstone at the elevation of 313.5 m asl (sampling site 5; figs. 2b and 5a) gave an age of 234.6 ± 9.1 kyrs bp (table 1). the oldest “kameni slap” fl owstone sample from the bottom of the drill core, at the elevation of 306 m asl, formed at 212.4 ± 8.1 kyrs bp (sampling site 3; figs. 2b, 5d and 5e), whereas the youngest sample (sampling site 4; fig. 2b and 5c) formed at 205.7 ± 10.9 kyrs bp (table 1). 4.3. stable isotope analysis the results of preliminary stable isotope analysis of 7 fl owstone and 3 shelfstone samples are included in table 2 and illustrated in figure 6. in general, the samples analyzed have figure 5: veternica cave fl owstone deposits. a) location of sample vet08-5/1 at sampling site 5 from an eroded fl owstone at the entrance to the “velebitaški” channel (fig. 2b). b) “kameni slap” fl owstone in the “touristic” part of the cave (sampling sites 3 and 4). karren and small dissolution scallops characterize the surface of the fl owstone. c) location of sample vet08-5/2 at sampling site 4 (fig. 2b) on fl owstone surface on top of the erosional cut through the “kameni slap”. d) arrow marks the location of sampling site 3 (fig. 2b), which is a coring site on the bottom of the erosional cut through the “kameni slap” fl owstone. e) photograph of the core from sampling site 3, with an arrow indicating location of sample vet08-5/3/1. table 1: uranium-series data for selected veternica cave fl owstone and shelfstone samples. material: site (sample) 238u (ng/g) 232th (pg/g) 230th/232th activity ratio 230th/238u activity ratio measured δ234u (‰) initial δ234u (‰) uncorrected age (yrs bp) corrected age (yrs bp) flowstone: 4 (vet08-5/2) 828 ± 2.4 345737 ± 1236 7.30 ± 0.04 0.996 ± 0.005 125±1 223±7 216073 ± 3411 205692 ± 10880 3 (vet08-5/3/1) 699 ± 1.9 211121 ± 498 9.98 ± 0.04 0.986 ± 0.004 110±1 200±5 219968 ± 3009 212400 ± 8105 5 (vet08 5/1) 787 ± 1.9 318073 ± 813 8.60 ± 0.03 1.138 ± 0.004 216±1 419±11 243227 ± 3273 234644 ± 9144 shelfstone: 2 (vet09-4) 924 ± 2.2 35260 ± 102 87.25 ± 0.39 1.089 ± 0.004 171±1 341±4 245477 ± 3549 244646 ± 3623 1 (vet08-4) 651 ± 1.5 284977 ± 662 8.15 ± 0.03 1.168 ± 0.005 149±1 435±20 389005 ± 13183 379776 ± 15528 yrs bp = years before present, where present = ad 2009. geologia croatica 219 lacković et al.: evolution of the veternica cave (medvednica mountain, croatia) drainage system... relatively invariable oxygen, and highly variable carbon isotope values, characteristic of meteoric precipitation. five of the fl owstone samples (three from sampling site 3 – deeper section of “kameni slap” fl owstone; one from sampling site 5 – fl owstone at the entrance to “velebitaški” channel; and one from sampling site 4 – surface layers of “kameni slap” fl owstone), cluster towards the most negative carbon and oxygen values measured, and partially overlap with the compositional fi eld defi ned by shelfstone samples, which on average have slightly less negative oxygen isotope values (fig. 6). the remaining two fl owstone samples (both from sampling site 4 – surface layers of “kameni slap” fl owstone) have substantially less negative carbon isotope values (fig. 6). 5. discussion field observations and age determination of the “majmunski prolaz” shelfstone (sampling sites 1 and 2; fig. 2b) yielded information about the timing and lateral extent of vadose and phreatic conditions in the veternica cave during the time period of shelfstone formation. since shelfstones generally form in quiet subsurface lakes and pools, their presence in veternica is related to the occurrence of standing water mark ing a signifi cant decrease in water fl ow intensity. as the age of both analyzed shelfstone samples (~380 and ~245 kyrs bp) coincides with the riss glacial maxima (ois 8 and 10; siegert, 2001), it is likely that the decrease in water fl ow through the cave was related to cold and dry glacial climatic periods. since the study area was located in a periglacial environment without any substantial evidence for major glaciations of the medvednica mountain and nearby areas (šikić, 1995), the main infl uence of pleistocene climatic oscillations on veternica cave hydrology was probably in terms of changing precipitation rates. it is also possible that during shelfstone formation, the “majmunski prolaz” channel was a hydrologically less active part of the cave system, and that the main water circulation was taking place in other lateral side channels or in channels at different elevations. given that the elevation difference between the 9 observed shelfstone levels is only 1.4 m, but their age range is at least 135 kyrs (age difference between the second lowest and the highest shelfstone), the period of shelfstone formation represents a relative stagnation in water level within this karst terrain. particular shelfstone levels probably refl ect water levels during periods of diminished water circulation alternating with more hydrologically active periods. the elevation difference between the shelfstones could be a consequence of the changing morphology of a palaeospring, or of very slow gradual karstifi cation. precipitation from stagnant palaeolake water of rather constant composition is also supported by the relatively uniform stable isotope values of the examined shelfstone samples (fig. 6). these values overlap in part with a group of fl owstone samples suggesting similar environmental conditions for precipitation of some of these cave speleothems. the slightly less negative oxygen isotope values of one of the shelfstone samples may be related to evaporation or temperature variations of the palaeolake waters (fig. 6). on the other hand, the substantially less negative carbon isotope values of the two examined fl owstone samples (fig. 6) suggest a greater variability in the composition of the water percolating through the cave under vadose conditions. during the formation of shelfstone in the vadose environment of the “majmunski prolaz” channel, the lower part of the cave (fig. 2b) was characterized by phreatic conditions. timing of the onset of the fl owstone formation in the upper part of the channel at 250 m from the entrance (figs. 2b and 5a, sampling site 5), prior to ~235 kyrs bp, indicates that the transition from phreatic into vadose conditions happened during a relatively short time period of less than ~10 kyrs. this relatively fast lowering of the water level in veternica could have been caused by rapid advance of downward karstifi cation as a consequence of the base level lowering due to enhanced tectonism and uplift of the western medvednica mountain relative to the sava river valley (regional base level). the present-day distribution of quaternary deposits table 2: carbon and oxygen stable isotope data for selected veternica cave fl owstone and shelfstone samples. material: sampling site (sample) δ13c (‰ vpdb) δ18o (‰ vpdb) flowstone: 5 (vet 08 5/1) 4 (vet 08 5/2 a) 4 (vet 08 5/2 b) 4 (vet 08 5/2 c) 3 (vet 08 5/3/1 a) 3 (vet 08 5/3/1 b) 3 (vet 08 5/3/1 c) –11.78 –11.43 –2.38 –7.07 –11.83 –10.85 –11.35 –10.31 –9.94 –8.55 –8.89 –9.12 –9.23 –9.48 shelfstone: 1 (vet 08-4) 2 (vet 09-4 b) 2 (vet 09-4 c) –11.11 –11.26 –11.23 –9.35 –8.45 –9.06 figure 6: results of preliminary stable isotope analysis of the veternica cave fl owstone and shelfstone deposits. geologia croatica 64/3geologia croatica 220 in the area suggests a total quaternary uplift of about 350 m along the southern fl anks of medvednica mt., including the late pleistocene and holocene (the last 130 kyrs) uplift of about 60 m (kuk et al., 2000). this supports active tectonism during the late quaternary, when veternica experienced rapid water table fall. during the period of enhanced vertical karstifi cation, those formerly phreatic channels (“touristic” part, fig. 2b) fi rst became epiphreatic or only occasionally flooded, and then completely dried out as the drainage capacity of the channels in dolostone deposits at lower elevations increased. the ages of “kameni slap” fl owstones from the lowermost part of the “touristic” part of veternica indicate the end of signifi cant hydrologic activity at the entrance area of the cave. as it was not possible to sample the oldest “kameni slap” fl owstone deposits, we could not determine the exact onset of fl owstone formation, but we established that it start ed before ~212 kyrs bp (sampling sites 3 and 4; fig. 2b). the tectonic uplift fi rst reactivated a vadose fl ow through the “majmunski prolaz” channel. this fl ow eroded most of the sediment from the lower parts of the channel, as supported by the presence of vadose downcutting of the channel bottom in the “touristic” part of the cave, from the “majmunski prolaz” channel downstream to “ponor 16 m” (fig. 2b). this downcutting was likely coeval with the formation and subsequent partial erosion of the “kameni slap” fl owstone (sampling sites 3 and 4; figs. 2b and 5c). at that time, the “ponor 16 m” was probably the main drainage channel for vadose fl ow, and part of the cave from “ponor 16 m” downstream to the cave entrance became completely dry as it is today. the preserved phreatic shape of the channel and the bottom sediments surface morphology between the cave entrance and “ponor 16 m” (fig. 2b), indicate phreatic conditions in this part of the channel until the cessation of hydrologic activity (e.g., palmer, 2007). the reconstructed timing of the end of hydrologic activity at the cave entrance is in agreement with previous studies indicating that the oldest clastic sediments at the cave entrance were deposited after hydrologic activity ceased at the end of the riss glaciation (prior to 130 to 150 kyrs bp; malez, 1963). after formation of the youngest “kameni slap” fl owstone (sampling site 4; ~205 kyrs bp), water fl ow from the “velebitaški” channel temporarily increased. this is refl ected in both erosional and corrosional forms present throughout the entire fl owstone surface and in a 40 cm deep erosional cut through the fl owstone (fig. 5). today, water fl ows only in the deeper part of the “velebitaški” channel, where it sinks into the “velebitaški siphon” (fig. 2b). the results of detailed gps measurements suggest that the medvednica region is still being actively uplifted (pribičević et al., 2007). present-day cave morphology indicates that lowering of the groundwater circulation level is an ongoing process, gradually advancing upward from the downstream end of the karst system. the morphology of younger generation veternica cave channels (fig. 2b) refl ects this advance: steep inclination of the hydrologically active channel towards the “main siphon”, and the presence of abandoned generations of channels and siphons, which were, during past karstifi cation phases, draining water from the main channel to the lower levels (e.g., “ponor 16 m”, “kukušni channel”, fig. 2b). to improve reconstruction of the geological history of the veternica cave, future studies should include the dating of the oldest fl owstones as well as shelfstones from all different levels, in addition to detailed sedimentological analyses and dating of clastic alluvial deposits from the cave channels. such multifaceted studies can provide unique and interesting information about the cave history that can then be shared with the public. numerous visitors are attracted annually to the veternica cave, not only because of its easy access and proximity to the large metropolitan area of zagreb, but also because this is one of the longest caves in croatia, rich in cave formations, while its deposits have yielded cave bear remains and neanderthal artifacts. this public interest in the cave is a perfect opportunity to disseminate the results of up-to-date scientifi c research on veternica, but it also necessitates the need for preservation and protection of this delicate cave system. 6. conclusions 1) the study of cave deposits from the hydrologically inactive part of the main channel in veternica cave documented the morphological evolution of the cave and surrounding area. 2) the cave entrance is at 320 metres asl. for 180 m from the entrance, there were phreatic conditions in the main cave channel until the end of its hydrological activity, while the main channel at 180 to 390 m from the cave entrance shows phreatic morphology with later vadose entrenchment. in this part of the channel there are fl owstone precipitates at 250 m from the cave entrance at elevations ranging from 306 to 313.5 m asl. 3) part of the channel that is farther inside the cave and higher upstream, has a tall, narrow morphology of vadose origin. nine different shelfstone remnants were observed in this part of the channel at elevations ranging from 318.8 to 320.2 m asl. these shelfstones mark the position of a free surface palaeolake that extended from 390 to 475 m from the present cave entrance. 4) u-th dating revealed the age of the highest shelfstone (from 320.2 m asl) of ~380 kyrs bp, and the age of the lowest analyzed shelfstone (from 318.9 m asl) of ~245 kyrs bp. dating of the fl owstones in the downstream part of the cave indicates their formation from ~235 to 205 kyrs bp. 5) the time interval between formation of the youngest shelfstone (representing phreatic conditions below their level), and the oldest fl owstone (marking the beginning of vadose conditions) represents a period of relatively fast water table fall between ~245 and 235 kyrs bp and the consequent transition from phreatic to vadose conditions in the “touristic” part of the cave. this fast water table lowering resulted in the preserved phreatic characteristics of the channel between the cave entrance and “ponor 16 m” (or for about 180 m from the cave entrance) according to the major change in channel and sediment morphology. geologia croatica 221 lacković et al.: evolution of the veternica cave (medvednica mountain, croatia) drainage system... aknowledgement we would like to thank dr. nenad buzjak and our caving friends from the velebit and samobor caving clubs for helping with fi eld work, the medvednica nature park and the kahn liberal arts institute at smith college for fi nancial support, and the croatian natural history museum for general support. dr. philippe audra (university of nice, france) provided useful comments on an earlier version of this manuscript. we also thank two anonymous reviewers for their detailed and thoughtful reviews. references asmerom, y., polyak, v., schwieters, j. & bouman, c. (2006): routine high-precision u-th isotope analysis for paleoclimate chronology.– geochimica et cosmochimica acta, 70, p. a24. auler, a.s. & smart, p.l. (2001): late quaternary paleoclimate in semiarid northeastern brazil from u-series dating of travertine and water-table speleothems.– quaternary research, 55, 159–167. bögli, a. (1980): karst hydrology and physical speleology.– springer-verlag, berlin, 284 p. božičević, s. (1976): hidrologija pećine veternice kraj zagreba na planini medvednici [hydrogeology of the veternica cave near zagreb on the medvednica mt. – in croatian].– 8. jugosl. geol. kongres, ljubljana, 4, 5–12. cheng, h., edwards, r.l., hoff, j., gallup, c.d., richards, d.a. & asmerom, y. (2000): the half-lives of uranium-234 and thorium-230.– chemical geology, 169, 17–33. croatian speleological server (2011): the caves in croatia longer than 1000 meters.– [online] http://www.speleologija.hr/karta.html [updated 11th july 2011]. čepelak, m. (1977): novija i buduća speleološka istraživanja u veternici [new and future speleological explorations in veternica – in croatian].– speleolog, 24–25, 1–8. čepelak, m. (1979): objašnjenje uz nacrt špilje veternice [explanation for the topographic survey of veternica cave – in croatian].– speleolog, zagreb, 26–27, 33–34. ford, d.c., lundberg, j., palmer, a.n., palmer, m.v., dreybrodt, w. & schwarcz, h.p. (1993): uranium–series dating of the draining of an aquifer: the example of wind cave, black hills, south dakota.– geological society of america bulletin, 105, 241–250. ford, d.c. & williams, p.w. (1989): karst geomorphology and hydrology.– chapman & hall, london, 601 p. gorjanović–kramberger, d. (1899): krš zagrebačke gore [karst of the medvednica mt. – in croatian].– hrvatski planinar, 11, 161–164. hill, c. & forti, p. (1997): cave minerals of the world, 2nd ed.– national speleological society, huntsville, 463 p. hirc, d. (1903): u zapadnom prigorju zagrebačke gore [western slopes of the medvednica mt. – in croatian].– hrvatski planinar, 1–2, 7–10. kuk, v., prelogović, e., sović, i., kuk, k. & šariri, k. (2000): seizmološke i seizmotektonske značajke šireg zagrebačkog područja [seismic and seismotectonic characteristics of the greater zagreb area – in croatian].– građevinar, 52/11, 647–653. malez, m. (1963): stratigrafska i paleontološka proučavanja diluvijalnog nalazišta u pećini veternici (medvednica) [stratigraphic and paleontological research of a diluvial site in veternica cave (medvednica mt.) – in croatian].– unpubl. phd thesis, university of zagreb, croatia, 372 p. malez, m. (1965): pećina veternica u medvednici. i opći speleološki pregled, ii stratigrafi ja kvartarnih taložina [veternica cave in the medvednica mt. i general speleological description, ii stratigraphy of quaternary deposits – in croatian].– acta geol., 5, 175–229. marjanac, t. (2007): špilja veternica – geološka riznica [veternica cave – a geological treasure – in croatian].– speleolog, zagreb, 55, 40–44. marjanac, t., marjanac, lj. & bermanec, v. (2005): veternica on medvednica mt. near zagreb – a cave developed in dolomites, clastics and pyroclastics. 13th international karstological school “classical karst”: karst in various rocks, postojna, slovenija. abstracts for posters, 32–33. miracle., p.t. & brajković, d. (2010): the palaeoecological signifi cance of the pleistocene mammalian fauna from veternica cave, croatia. revision of the lagomorpha, canidae, mustelidae and felidae.– geologia croatica, 63/2, 207–224. palmer, a. (2007): cave geology.– cave books, cave research foundation, usa, 454 p. panuška, lj. & marjanac, t. (1977): rezultati nekih novijih geoloških istraživanja u spilji veternici [results of new geological research in veternica cave – in croatian].– speleolog, 24–25, 13–14. poljak, j. (1934): pećina veternica u zagrebačkoj gori [veternica cave on the medvednica mt. – in croatian].– priroda, 5, 133–139. pribičević, b., medak, d. & đapo, a. (2007): progušćenje točaka geodinamičke mreže grada zagreba u podsljemenskoj zoni [addition to geodynamical monitoring points for the city of zagreb in the medvednica foothill area – in croatian].– geod. list, 4, 247–258. siegert, m.j. (2001): ice sheets and late quaternary environmental change.– john wiley & sons ltd, london, 231 p. sutlović, a. (1991): novi metri u staroj veternici [new measurements in the veternica cave – in croatian].– velebiten, 8, 34–36. szabo, b.j., kolesar, p.t., riggs, a.c., winograd, i.j. & ludwig, k.r. (1994): paleoclimatic inferences from a 120,000yr calcite record of water-table fl uctuation in browns room of devils hole, nevada.– quaternary research, 41, 59–69. šikić, k. (1995): prikaz geološke građe medvednice [geological overview of the medvednica mt. – in croatian].– in: šikić, k (ed.): geološki vodič medvednice. hrvatski geološki institut, zagreb, 7–30. manuscript received july 11, 2011 revised manuscript accepted september 01, 2011 available online october 26, 2011 horvat.indd �ab stra ct traditional techniques to identify a depositional body from core data are costly and sometimes diffi cult to extrapolate to uncored wells. the application of kohonen’s self organized map (som) approach may be useful for the interpretation of a depositional rock body through well-log data. som is based on a clustering algorithm and this method can be used to discover spatial patterns occurring as clusters in unstructured data sets. an example of the application of som is presented whereby clusters through som can indicate the contours of well-known depositional patterns such as sub-environments. keywords: clustering method, depositional environment, neural network, pattern recognition defi ning depositional environments by using neural networks � janina horváth department of geology and palaeontology, university of szeged, h-6722, szeged, egyetem u. 2–6, hungary; (th.janina@geo.u-szeged.hu) doi: 104154/gc.2011.21 geologia croatica 64/3 251–258 10 figs. 2 tabs. zagreb 2011 geologia croaticageologia croatica 1. introduction the neural network approach is a well-known development tool, which became popular within the last couple of decades. supervised and unsupervised trainable networks are used in many different fi elds of geology, especially petroleum geology or facies analysis e.g. the unsupervised network as a tool for lithofacies identifi cation (chang et al., 2002), application of a supervised neural network for predicting permeability from porosity (rogers et al., 1995), using a supervised neural network tool in reservoir characterization (ahmed et al., 1997). however, supervised networks are more frequently used, because the unsupervised learning networks can solve specifi c problems like clustering or, pattern recognitions problems as a way of defi ning spatial patterns. application of a particular unsupervised neural network called kohonen’s network (in other words self organized map, abbreviated som) in the identifi cation spatial pattern of some delta-plain sub-environments is demonstrated here. kohonen’s neural network has been successfully applied to studies with different representation methods or as a tool to defi ne clusters e.g. a well log interpretation model for the determination of reservoir facies and fl uid contents (akinyokun et al., 2009), lithofacies identifi cation (chang et al., 2002), and classifi cation of biogenic sedimentation (ultsch at al., 1995). traditional techniques to identify depositional environments from core data are diffi cult as they require a large dataset and/or are less precise than some results gained by using mathematical models for mapping. this study shows a neural network methodology which can handle simultaneously more point data and even join more attributes, or property of data points. therefore the som approach may be regarded as a possible method for pattern recognition by parallel analysis of multiple data sources. in this study we describe a method based mostly on data of electrofacies obtained from e-logs. it is a possible tool for the characterization of depositional environments comprising the rock body. contrary to traditional geostatistical interpolation methods, neural networks as clustering schemes can provide many possibilities for modeling. kohonen’s algorithm reveals these spatial patterns in the terms of clusters. from this aspect, som is quite similar to general clustering algorithms, although ultsch (1995) has shown that som can even recognize point-clusters in those situations where traditional cluster techniques fail to fi nd any reasonable groups. here, spatial patterns are defi ned as spatial groups of points, where points are bounded by a polygon (e.g. contour of sand content). by using this defi nition, one can conclude, that pattern recognition can be drawn back to a clustering problem. the shape of the polygon, i.e. the contour geometry, refl ects the geologia croatica 64/3geologia croatica 252 2d or 3d geometry of the depositional facies identifi ed. this is the sedimentary environment according to pettijohn and potter (1972). in this study, the main emphasis is given to the following issues: (1) demonstration of how a known depositional geometry outlined by sand-content contours can be honored by using som analysis of points of three petrophysical grids. this analysis relies on good average porosity, net pore volume and hydraulic conductivity grids; (2) description of an example of the application of this robust approach in re-recognizing the known distributary mouth bar shape in a particular pannonian reservoir. 2. applied method 2.1. self organized maps (som) kohonen’s neural network (or self organized map (som)) means that the neurons are organized in a grid (fig. 1) as a ‘map’. however it is not a real map since it does not assign any spatial coordinates to the samples. so, self organizing gives a ‘map’ where the nearby locations represent inputs with similar properties. som is a type of competitive and unsupervised network. the competitive and unsupervised learning algorithm implies that the network has to have the ability to recognize the structure of a multidimensional basic data set, by the method of dimension reduction (kohonen, 1982, kohonen 2001; haykin, 1999; patterson, 1996; fausett, 1994). this reduction is only a “queasy” one, since each neuron is an n-dimensional weight-vector, where n is equal to the dimension of the input vectors (fig. 1). the main goal of som is to represent data points with fewer representatives preserving the original topology (johannson, 2003). even the unsupervised learning character implies that only one data set is available for analysis. so the data structure is explored within the input set without using any reference dataset. in the case of the supervised neural network, the training processes depend on training examples and each example is a pair of an input objects. in contrast with the unsupervised network, the learning processes are based on unlabelled examples. the framework (fig. 2) of kohonen’s neural network also demonstrates this difference between the supervised and unsupervised neural networks. there are no real output layers, but neurons are arranged into a grid of dots. in other words, the grid is the output” layer. this is the so-called kohonen’s layer. it contains m neurons; each neuron includes one output cluster. figure 1 shows that in this layer neurons give a two dimensional map (usually we can use one or two dimensional kohonen’ layer), however the neurons saved and represent the original data dimension because each neuron is represented as an n dimensional vector, where n is the dimension of the input, training, vectors. weighted xi inputs are processed by all three neurons (fig. 2). each neuron computes its weighted input, but only the neuron with the largest excitation is the winner. these units are adjusted to cluster the training data using the activation values of winning neurons. in kohonen’s layer the other units are reserved by this active element through the lateral connections during training shown in fig. 2. an advantage of the som network is that it attempts to learn the structure of the original data. it means that the training data set gives the contact between the original data points and identifi ed classes. if new data, unlike previous cases, is encountered, the network fails to recognize it which indicates novelty. therefore, in the next learning step, the grid is updated based on the novelty. the updating process is quite similar to that of the k-means algorithm, where the arrangements of cluster-centroids change in the regular low-dimensional grid. however, in case of som, changing the position of neurons in the data space infl uences the positions of its neighbors through the lateral connections within a predetermined distance. since som consists of neurons organized on a regular low-dimensional grid, these neurons control the classifi cation of data using a suitable distance. the input vectors are compared step by step with the reference vectors using a neighboring function and the grid is revised continuously using a winning neuron algorithm. during the comparison figure 1: kohonen’s layer with n-dimensional neurons. figure 2: network of three competing units. janina horváth: defi ning depositional environments by using neural networks geologia croatica 253 process, each sample input vector is randomly drawn from the input data set, and their similarities to the ‘codebook’ vectors are computed. this process is based on euclidean distance that measures distance from the data sample to each neuron to obtain the winning neuron (lampinen et al., 2005).owever better selections use either mahalanobis distance, (developed by mahalanobis in 1936), or cosine distance as alternative measures. the latter is derived from correlations between variables in the property space. kohonen’s network learns iteratively and uses the modifi ed hebb-rule as the winning neuron algorithm (lampinen et al, 2005). the modifi ed law is w(t+1)=w(t)+ρ(t)´(x–w(t)).where x is the training case, w(t) is weight, and ρ(t) is the learning rate. the application of neural networks is relatively simple. an artifi cial network studies the data structure, which means that it necessarily must have some preliminary empirical knowledge e.g. on appropriate size of network, rate of learning, number of learning steps. in this case, the size of the network corresponds to the number of neurons representing the clusters of which numbers must be given previously. this setting depends on preliminary expertise. 2.2.1. pattern recognition as a clustering method som is a type of clustering method. it differs from any traditional clustering method in its robustness. however it needs, like any ‘traditional k-mean algorithm’, to input the number of groups to be revealed. som, (as any clustering method), provides an opportunity for deriving solutions for geological problems which can be related to different clustering problems, such as pattern recognition (ultsch, 1995). for implementation, kohonen’s network has been used as it is possible to recognize spatial patterns being defi ned as spatial groups of points bounded by a polygon. it has potential for applying pattern recognition to problems such as identifying the spatial pattern of a sub-environment on a delta plain, which is resoluble by applying the som method based on a clustering algorithm. shapes shall be construed as clusters of data points that are bounded by a polygon which implies that pattern recognition is a clustering problem. however, this approach raises the question of the defi nition of patterns as statistical groups. within a pattern, there are points with the same or similar properties. in practice, this means that all points in a sub-set represent a certain cluster which is bounded by polygons. a polygon represents the shape and refl ects the borders of subenvironments, where the properties change between separate clusters. figure 3 demonstrates an example for mapping clusters using the original coordinates. som creates cm clusters (m is the number of clusters) based on the property values of data points without original spatial coordinates. after the clustering process we map the resulting clusters as patterns using the original coordinates. in this manner the different properties clusters are mapped and the pattern is visualized on the map. thus after the clustering process, the resulting clusters are patterns in a map using the original coordinates. 2.2.2. recognisable patterns in the map the mapping processes compose the closed patterns by the arrangement of the points in space through the original (xi,yi) coordinates. in this case it is necessary to give some conditions and defi nitions for recognizing patterns for mathematical reasons. (1) a closed pattern means that there is at least one inner point of the group. (2) a point is an inner point if all of its neighboring points belong to the same cluster, i.e. there are at least four edge-neighbours to it. (3) the border of a shape is defi ned by a point which has neighbours from another cluster. of course a pattern might also have more neighbours. (4) within a shape we can also defi ne another shape if it has inner points. otherwise we should disregard these points as a pattern. however in this case, the question is how many inner points are enough to defi ne a pattern. the answer depends on the grid dissolution. since a 100 x 100 m grid size was applied over the study area, we can defi ne the inner pattern which has at least one inner point. (this consideration gives 5 inner points in case of 50 x 50 m grid size and 25 inner points in case of 25 x 25 m grid size and so on.) (5) the ‘inner shape’, should be covered by border points of only one other cluster. 3. study area data originated from the szőreg-1 reservoir (algyő field) that was used as a test area for the application of pattern recognition of palaeoenvironments in a clastic reservoir using the kohonen’s neural network. the algyő field is the largest hungarian hydrocarbon accumulation consisting of several oil and gas bearing reservoirs (fig. 4). the upper memfigure 3: arrangement points on the map. where pi means data points within clusters (cm); and (xi ,yi) means the positions of data points with their original coordinates in the map. geologia croatica 64/3geologia croatica 254 bers of these reservoirs developed in a pannonian delta system as the consequences of complex lateral delta-shifting and prograding phases. they can be subdivided into delta slope and delta plain rock bodies. the sills of the individual reservoirs were formed during delta abandonment phases. below this series, the lower reservoirs are regarded as turbidity rock bodies of partly pro-delta fans and partly deep basin origin (révész, 1982). the szőreg-1 oil reservoir, with a large gas cap is one of the largest rock bodies within the delta plain record (fig. 4). its average gross thickness is about 35 m, but locally it can be up to a maximum of 50 m thick. earlier works by révész (1982), geiger et al., (1998) and geiger (2005) have proved its delta plain origin with a signifi cant amount of fl uvial channel sedimentation. figure 5 shows the original well density, the dataset is from 506 well on szőreg-1 study area. 4. data pre-processing and analysis by som the network depends on the quality and quantity of training data, so data pre-processing is very important. this is as follows: 1) defi nition of the data type (discrete or constant), 2) calculation of statistics: mean, standard deviation, and 3) selection of outlier data. no 1 is critical because the outlier data reduces the effi ciency of the network.in the case of category data, it is necessary to encode or scale the data. in this study we used continuous variable data. it is imperative to set the initial values for the training rate and the neighborhood radius. the kohonen-learning rate is altered linearly from the fi rst to the last training cycle. we specifi ed 0.3 for the start value and 0.02 for the end value. the neighborhood radius designates the adjacent area centered on the winning unit; in this case the size was 1 and specifi ed a 3x3 square. normal randomization of weights was used for the training; the mean and variance are specifi ed, and are used to draw the initial weight values. the second important step is to defi ne the training, test and validation sets for training of som. the original database comprises 7500 points (grid points). this dataset is deconstructed into three sub-sets (training-, testand validation set) using a random number generator to avoid bias. 60% of this database is used for building a neural network by som as a training set, 20% as a test, and 20% as a validation set. training set: this set is important to learn to fi t the parameters of the clusters (in this case clusters are the neurons that characterized the clusters). som is applied to fi nd the optimal weights to update the kohonen’s layer and to position the neurons of clusters. validation set: this set is applied to tune the parameters of a classifi er, and determine the stopping point of learning process. test set: this set lends itself to assess the performance of the trained clusters. after pre-processing, the fi rst step only sampled distributary mouth bars developed in szőreg-1 to analyze how the som method can recognize the pattern for this part. the pattern of distributary mouth bars was given by sand contours that can refl ect the geometry (figs. 6a,b). it was an imporfigure 4: macro-sedimentological model of the pannonian series of algyő (after bérczi, 1988). figure 5: well density of the study area (szőreg-1 reservoir). janina horváth: defi ning depositional environments by using neural networks geologia croatica 255 tant step since it can show how well the som-method refl ects patterns jointly through three other variables. these variables were porosity, net pore volume and hydraulic conductivity data (figs. 7a,b). the input data set comprises 2200 grid points (with 100x100 m dissolution), randomly divided into three (training, test and validation) subsets. the predefi ned number of clusters was tuned into 3, 4 and higher. in the case of more than 4 clusters, the algorithm became too confused for interpretation. even, after mapping these results it did not constitute disjunctive clusters. in the fi rst run, the minimum number of clusters is easier to tune in 3 because distributary mouth bars can be divided into three sub-environments as channel, outer bar, and bar crest. after the clustering, we mapped the patterns. in the maps these patterns are the separated clusters of the analyzed area (distributary mouth bars) and this patterns mean the blocks of similar properties. figure 8a,b represents the mapped result of the fi rst run of som. the pattern within this depositional environment can affect the spatial arrangement of reservoir properties. usually the sand contour used to refl ect the spatial patterns but in the case of the clustering method and after that the mapping of clusters, similar patterns are discernible like the maps of three original properties (figs. 7a,c) or map of sand contour (fig. 6b). in this case the resultmaps can demonstrate that it is also possible to apply clustering methods for outline the depositional geometry which are based on other three petrophysical parameters jointly. figure 6: a) gross thickness map of the szőreg-1 reservoir (entire area), b) gross thickness map of the area of the distributary mouth bars in the szőreg-1 reservoir. figure 7: a) porosity map of distributary mouth bars in the szőreg-1 reservoir, b) hfi map of distributary mouth bars in the szőreg-1 reservoir, c) hk map of distributary mouth bars in the szőreg-1 reservoir. a) b) a) b) c) geologia croatica 64/3geologia croatica 256 in the second run, we have involved each of the available 7500 grid points of the ‘basic’ grid system (with 100x100 m resolution, derived from well 506, fig. 5). in addition to recognizing the patterns again, the goal was also to identify the contours of the distributary bars. in this case, the number of clusters was tuned in 4 and 6, because we assumed at least one, but possibly two additional groups compared to the fi rst run. figures 9 a,b represents the mapped result of the second run of som. it expresses again, that the boundary of this depositional environment can also affect the spatial arrangement of reservoir properties. however, if we compare the mapped clusters to the original contours of the distributary mouth bars, figure 10 shows the similarities and differences. it can be seen that joint use of three variables in the som method produces a similar pattern within the distributary mouth bars as using one variable (i.e. sand content), but the contours of the shapes are different. so, the mapped results show the clusters which contain the points with similar properties in the present stage of diagenesis. in both cases, the run time of the training algorithm depends primarily on the size of the network and only secondarily on the number of training steps. the presented mapped results (figs. 8,9) are composed by setting 1000 learning steps in the som process. for this setting, (above mentioned numbers of clusters and number of learning steps) the run of som gives similar values for the error rates. table 1 shows the rate of errors for each set. figure 9: a) mapped result for 4 clusters, where clusters contain points with similar properties in the present stage of diagenesis, b) mapped result for 6 clusters, where clusters contain points with similar properties in the present stage of diagenesis. figure 8: mapped result for 3 clusters, where clusters contain points with similar properties in the present stage of diagenesis, b) mapped result for 4 clusters, where clusters contain points with similar properties in the present stage of diagenesis. a) b) a) b) a) b) janina horváth: defi ning depositional environments by using neural networks geologia croatica 257 besides the error rates of sets, we can determine the goodness of clustering of som. discriminant analysis can show how well the group a particular case belongs to can be predicted (see table 2 a-d). since the size of each cluster is not the same (the clusters contain different amounts of points), the priori probabilities (p) are not equal to 1/3 for each subset. the fi rst column of the spreadsheet indicates the percentage of cases that are correctly classifi ed in each cluster. other columns show the number of misclassifi cations. according to discriminant analysis, the results of som are 95% adequate on average. figure 10: mapped result for 6 clusters with the original geometry of distributary mouth bars by sand content, (where clusters contain points with similar properties in the present stage of diagenesis). table 1: error rates of running sets in case of running a-b-c-d. errors rate of sets case a) case b) case c) case d) training set 0.02786 0.028644 0.01515 0.01515 test set 0.020765 0.028264 0.031158 0.031158 validation set 0.019769 0.028178 0.0319757 0.031957 table 2a: classifi cation matrix (distributary mouth bars – 4 clusters) c_i ith cluster percent corrects c_1 p=0.16789 c_2 p=0.39853 c_3 p=0.18582 c_4 p=0.24830 c_1 88.02589 544 56 0 18 c_2 99.38651 0 1458 9 0 c_3 84.31085 0 107 575 0 c_4 92.88840 42 23 0 849 total 93.07253 586 1644 584 867 table 2b: classifi cation matrix (distributary mouth bars – 3 clusters) c_i ith cluster percent correct c_1 p=0.45314 c_2 p=0.31459 c_3 p=0.23227 c_1 98.32134 1640 28 0 c_2 96.80483 30 1121 7 c_3 96.49123 0 30 825 total 97.41918 1670 1179 832 table 2c: classifi cation matrix (entire dataset – 6 clusters) c_i ith cluster percent corrects c_1 p=0.23560 c_2 =0.14747 c_3 p=0.25400 c_4 p=0.13680 c_5 p=0.11200 c_6 p=0.11413 c_1 94.68025 1673 0 72 4 18 0 c_2 99.18626 0 1097 0 9 0 0 c_3 97.42782 43 0 1856 6 0 0 c_4 94.15205 34 0 0 966 0 26 c_5 88.33334 26 0 0 15 742 57 c_6 92.87383 0 18 0 0 43 795 total 95.05334 1776 1115 1928 1000 803 878 table 2d: classifi cation matrix (entire dataset – 4 clusters) c_i ith cluster percent correct c_1 p=0.35520 c_2 p=0.15800 c_3 p=0.32853 c_4 p=0.15827 c_1 94.68025 1673 0 72 4 c_2 99.18626 0 1097 0 9 c_3 97.42782 43 0 1856 6 c_4 94.15205 34 0 0 966 total 95.05334 1776 1115 1928 1000 geologia croatica 64/3geologia croatica 258 5. conclusions usually kohonen’s network is applied to solve classical pattern recognition problems such as the recognition of a writing character or pictures. frequently nonetheless, it can be applied to identifying a pattern as a classifi cation problem, since in the background of pattern recognition there are clustering problems. this paper demonstrated the approach of using an unsupervised neural network to distinguish parts of the depositional sub-environment as clusters which contain points with similar properties in the present stage of diagenesis. thus the som is an adequate tool to help identify genetic geological environments, sub-environments supplemented with the mapping process. the fi rst test using the som-method refl ected considerably well the patterns of the distributary mouth bars using three variables (figs. 7 a,b). in the case of the second run of som, the mapped results cluster does not show exactly the same boundaries of the distributary mouth bars, but a similar pattern within the area can be recognized. this paper focused on joint handling of more property to characterize parts of the sub-environment; and then mapping these as arranged points in space using some defi ned rules for geometry. in fact, the neural network answers do not differ significantly from the original geological model obtained. however, differences are visible, especially at the contour of distributary mouth bars. this raises the question of whether the differences show greater accuracy or greater uncertainty. nevertheless the discriminant analyses show that the clusters are well-defi ned at least on average for 95 % of the time. references ahmed, t., link, c.a., porter, k.w., wideman, c.j., himmer, p. & braun, j. (1997): application of neural network parameter prediction in reservoir characterization and simulation – a case history: the rabbit hills field – paper spe 38985 presented at the 1997 spe latin american and caribbean petroleum engineering conference and exhibition held in rio de janeiro, bra zil, 30 august–3 september 1997. doi: 10.2118/38985-ms akinyokun, o.c., enikanselu, p.a., adeyemo, a.b. & adesida, a. (2009): well log interpretation model for the determination of lithology and fl uid contents.– the pacifi c journal of science and technology, springer. bérczi, i. (1988): preliminary sedimentological investigations of a neogene depression in the great hungarian plain.– in: royden & horváth (ed.): the pannonian basin – a study in basin evolution.– aapg memoir, 45, 107–116. chang, h.-c., kopaska-merkel, d.c. & chen, h.-c. (2002): identifi cation of lithofacies using kohonen self-organizing maps.– computers & geosciences, 28, 223–229. doi: 10.1016/s0098-3004(01)00067-x fausett, l. (1994): fundamentals of neural networks – architectures, algorithms and applications, prentice hall, englewood cliffs, nj. geiger, j. (2005): sedimentological study of szőreg-1 reservoir (algyő field): a kind of combination of traditional and 3d sedimentological approaches.– in: hum, l. et al. (eds.): environmental historical studies from the late tertiary and quarternary of hungary. department of geology and paleontology, university of szeged, 25–45. geiger, j., kissné, v.k., veres, k. & komlós, j. (1998): a szőreg-1 telep 3d rezervoár geológiai modellje. (3d sedimentological modelling of szőreg-1 reservoir), kummi jelentés. p. 216. tsz. 156–5636., szeged. haykin, s. (1999): neural networks: a comprehensive foundation. macmillan.– the knowledge engineering review, new york, 13/4, 409–412. doi: 10.1017/s0269888998214044 johansson, j., jern, m., treloar, r., jansson m. (2003): “visual analysis based on algorithmic classifi cation” iv, seventh international conference on information visualization, p. 86. kohonen, t. (1982): self-organized formation of topologically correct feature maps.– biological cybernetics, 43, 59–69. doi: 10.1007/ bf00337288 kohonen, t. (2001): self organized maps – springer, berlin, germany. lampinen, t., laurikkala, m., koivisto, h. & honkanen, t. (2005): profi ling network applications with fuzzy c-means and self-organizing maps studies in computational intelligence, volume 4/2005 classifi cation and clustering for knowledge discovery, springer berlin / heidelberg. mahalanobis, p.c. (1936): “on the generalized distance in statistics”. proceedings of the national institute of sciences of india 2/1: 49–55. patterson, d. (1996) artifi cial neural networks, prentice hall, singapore, xy p. pettijohn, f.j. & potter, p.e. (1972): sand and sandstone.– sprin ger verlag berlin – heidelberg – new york, 618 p. révész, i. (1982): az algyői maros-szőreg szénhidrogéntelepek üledékföldtani modellje – egy fosszilis delta fejlődéstörténete. (modelling of maros-szőreg hydrocarbon reservoir (algyő field) – a develop history of the pannonian fossil delta.).– kőolaj és földgáz, 115, 176–177. rogers, s.j., chen, h.c., kopaska-merkel, d.c. & fang, j.h. (1995): predicting permeability from porosity using artifi cial neural networks. – aapg bulletin, 79/12, 1786–1797. ultsch, a. (1995): self organizing neural networks perform different from statistical k-means clustering.– in: proc. gfkl, basel, swiss. ultsch, a., korus, d. & wehrmann, a. (1995): neural networks and their rules for classifi cation in marine geology, raum und zeit in umweltinformations-systemen, 9th intl. symposium on computer science for environmental protection csep ´95, vol. i, ed. gifachausschuß 4.6 “informatik im umweltschutz” vol. 7, metropolis-verlag, marburg, 676–693. manuscript received december 03, 2010 revised manuscript accepted july 11, 2011 available online october 26, 2011 04 bakrac.indd bakrač et al.: middle and late miocene palnological biozonation of the south-western part of central paratethys (croatia) 207 � ab stra ct middle and late miocene palynological biozonation of the south-western parts of central paratethys (croatia) is presented based on organic-walled phytoplankton. nine characteristic palynozones of regional palynostratigraphic range are recognized, e.g. early badenian (langhian) cribroperidinium tenuitabulatum (cte), badenian (late langhian – earliest serravallian) unipontidinium aquaeductum (uaq), late badenian (early serravallian) cleistosphaeridium placacanthum (cpl), sarmatian (middle and late serravallian) polysphaeridium zoharyi – lingulodinium machaerophorum (pzo-lma), early early pannonian s.l. mecsekia ultima – spiniferites bentorii pannonicus (mulspa), middle early pannonian s.l. spiniferites bentorii oblongus (sob), late early pannonian s.l. pontiadinium pecsvaradensis (ppe), early late pannonian s.l. spiniferites validus (sva), and late late pannonian s.l. galeacysta etrusca (get). as inferred from the regional palynostratigraphic correlation, the signals of two transgressions after the isolation of paratethys during the sarmatian are recognised: the fi rst one in the late early pannonian, when mediterranean dinofl agellates migrated into the pannonian basin, and the second one in the late pannonian, when endemic paratethyan taxa migrated into the mediterranean. keywords: palynology, miocene, biozonation, dinofl agellate, paratethys, mediterranean middle and late miocene palynological biozonation of the south-western part of central paratethys (croatia) � koraljka bakrač1, georg koch1 and jasenka sremac2 1 croatian geological survey, sachsova 2, hr-10000 zagreb, croatia; (kbakrac@hgi-cgs.hr) 2 university zagreb, faculty of science, department of geology, horvatovac 102a, hr-10000 zagreb, croatia doi: 104154/gc.2012.12 geologia croatica 65/2 207–222 3 figs. 2 pls. zagreb 2012 geologia croaticageologia croatica 1. introduction the fi rst dinofl agellate zonations for the neogene of southwestern europe were proposed by powell (1986a, b, c), biffi & manum (1988), and zevenboom (1995), and for the tertiary of north-western europe by costa & manum (1988), respectively. miocene dinocyst assemblages from central paratethys were studied by several authors, e.g., baltes (1967, 1969), hochuli (1978) and jiménez-moreno et al. (2006) for the early and middle miocene, and sütő-szentai (1985; 1988; 1989; 1991; 1994, 2005) for the late miocene. jiménez-moreno et al. (2006) presented the fi rst dinocyst biostratigraphy for the ottnangian, badenian and sarmatian (pro parte) deposits of the western and middle part of the paratethys. two short reports have been published from the karpatian – badenian strata of the styrian basin (soliman & piller, 2007). marine paratethys deposits are comparable with the mediterranean biostratigraphy zones proposed by rögl (1998), and popov et al. (2006). problems arise in brackish and freshwater paratethyan environments in the sarmatian, after the isolation of the pannonian basin. marine fossils were extinct and replaced by a new endemic fauna. therefore, the local biozonation of the pannonian basin deposits was established on the basis of the organic-walled phytoplankton index fossils. geologia croatica 65/2geologia croatica 208 successful applications of dinocyst studies were carried out in sequence stratigraphy starting with haq et al. (1987). the key to recognizing the 3rd and 4th order depositional sequences is the maximum fl ooding surface, marked by the abrupt changes in dinocyst abundance. stratigraphic timing of this surface is extremely important in sequence stratigraphic analysis. therefore, the main goal for future work will be recognition of the maximum fl ooding surface in the pannonian basin, and based on it, correlation of proposed palynological zones with established zones in the mediterranean area. 2. geology of the study area paratethys was an enclosed sea existing from oli gocene to middle miocene times, consisting of a chain of basins of various tectonic origins (báldi, 1980). these basins were covered most of the time by the same mass of water, sharing a similar aquatic biota, with communication between the mediterranean and the indo-pacifi c realms. when paratethys became separated from other seas at the beginning of the late miocene, the lake pannon individualized with decreasing salinity (magyar et al., 1999a). as both paratethys and lake pannon were characterized by an increasing rate of endemism, a local chronostratigraphic scheme was developed. the karpatian/badenian boundary is characterized by a signifi cant sea level fall (haq et al., 1988; hardenbol et al., 1998), expressed as a hiatus (“styrian unconformity”), traceable throughout central paratethys (rögl et al., 2002, harzhauser & piller, 2007). continuous sedimentafigure 1: location of the studied area: (a) pannonian basin; (b) study area; (a) žumberačka gora; (b) hrvatsko zagorje and medvednica mt.; (c) slavonija. bakrač et al.: middle and late miocene palnological biozonation of the south-western part of central paratethys (croatia) geologia croatica 209 tion from the karpatian to the badenian has never been observed (piller et al., 2007). in early badenian times (čuč-i, vej-iii; fig. 1b) (avanić et al., 1995), the entire area was under marine transgression, and only the uppermost parts of the mountains remained as islands in the newly formed sea (kováč et al., 2007). ćorić et al. (2009) suggest a distinctly younger age for the neogene sedimentation in the north croatian basins than was formerly considered. they correlate the initial marine transgression with the middle part of the early badenian, which is more than 2 m.y. younger than the previously inferred datum, and at least 1 m.y. younger than the lower boundary of the badenian and the middle miocene. they write that probably the complete depositional cycle of its lower basinal infi ll, comprising the lacustrine and the early marine sediments, belongs to the middle miocene, badenian stage. in the proximal part of the basin a paralic environment was formed (vrh-i; fig. 1a) (bakrač et al., 2010). late badenian re-opening of the indo-pacifi c seaway (rögl, 1996) caused the sea-level rise. certain areas emerged from the sea while other parts were subjected to transgression (lst-ii, zaj-i, nac-i; figs. 1b, c). at the end of the badenian, some oscillation of the sea level occurred, particularly in the marginal parts of the basin (jur-ii; fig. 1a). the badenian is conformably overlain by the sarmatian sediments, locally developed over the whole of the studied area (zaj-i, lst-i, fig. 1b; jur-i, figs. 1 a; nac-i, fig. 1 c). the transition from the badenian to sarmatian deposits is observed in žumberak (vrsaljko et al., 2005), hrvatsko zagorje (zaj-i; fig. 1b) and slavonija (nac-i; fig. 1c) (pavelić et al., 2003; vasiliev et al., 2007). important palaeoecological changes occurred after disconnection of paratethys and tethys that conditioned major facies changes. the sarmatian sea was reduced in size. the terrestrial infl uence gradually increased, followed by the decreased salinity. straits between the pannonian basin and the rest of the sea resulted in the complete mixing of waters. in the central part of the basin however, the littoral facies of the sarmatian rocks indicate that many islands existed there (magyar et al., 1999a). piller & harzhauser (2005), subdivided the sarmatian into a short early sarmatian period with normal marine conditions, in marginal areas probably mixohaline conditions and a longer late sarmatian period of normal marine to occasional hypersaline conditions. a relative sea level fall resulted in isolation of the intracarpathian waters from the rest of paratethys, forming lake pannon. a previously shallow-water central part of the basin became dry land. only small, scattered patches of the originally thin sarmatian deposits escaped complete erosion. correlation outside of central paratethys is problematical, due to the restricted connection of paratethys to the mediterranean and the lack of almost all stenohaline faunas. planktonic foraminifera are almost entirely absent, and the only survivors are calcareous nannoplankton, low in diversity and with endemic taxa (piller et al., 2007). the transition from the sarmatian to the pannonian deposits is observed on the south-western slopes of medvednica mt. (kst-i; fig. 1b), and in slavonija (nac-ii; fig. 1c) (pavelić et al., 2003). the lower pannonian s.l. sediments cover signifi cant areas in every basin or depression in the croatian part of the pannonian basin. the reduction in salinity continued, so brackish and freshwater sediments prevail. based on endemic molluscs, the paratethys deposits of the late miocene in croatia were stratigraphically divided into four acrozones (range zones). the lowest pannonian deposits (“croatica beds”) are observed in hrvatsko zagorje (krt-i: fig. 1b), medvednica mt. (kst-i; fig. 1b), slavonija (nac-ii; fig. 1c), and upper lower pannonian deposits (“banatica beds”) (mal-i; fig. 1a) at medvednica mt. (kst-i; fig. 1b), and slavonija (nac-ii; fig. 1c). the lake water gradually fl ooded signifi cant land areas. at the end of the lower pannonian, during the spiniferites paradoxus biochron, ca. 9.5 ma, lake pannon reached its largest areal extent (magyar et al., 1999a). sediments of this age often overlie much older formations in the basin margins, indicating transgression (krš-i, mal-i, fig. 1 a; kob-i, sam-i, pšć-i, pož-i, and-i, and-ii, mir-i, tol-ii; fig. 1 b). progradation from the northwest started during this biochron, and the vienna basin dried up by the end of it. this could be seen in the geological columns in hrvatsko zagorje (pož-i, tol-ii; fig. 1b) where much more sand is observed. during the congeria praerhomboidea biochron (ca. 9.0 ma), the lake area shrank to half its former size (magyar et al., 1999a). deltas from the northwest and northeast advanced towards the centre of the basin. in the early late pannonian s.l., a connection between the pannonian and dacian basins was established. the lower upper pannonian sediments, known as the “abichi beds”, are mostly fi negrained sandstones in alternation with clayey and silty marls. the “rhomboidea beds” were deposited during the late pannonian, and cover very large areas of the pannonian basin (lučić et al., 2001). water levels rose again during the early congeria rhomboidea biochron, ca. 8.0 ma (magyar et al., 1999a). only a few islands remained above the lake level (išć-i, sel-i, beki, bek-ii, fig. 1b; nac-iii, kra-i; fig. 1c). the effect of the water-level rise however, was balanced by high terrigenous infl ux in the north-eastern part of the lake, where aggradation occurred at this time (juhász, 1994). terrigenous infl ux was even greater in the northwest, where progradation of deltas continued towards the south (mal-i, sel-i, bek-ii). as the basin fi lled with sediments from the north and northwest, the lake was limited to north-eastern croatia (nac-iii, kra-i; fig. 1c). rare and sporadic fi ndings of polyhaline nannofossils (kollányi, 2000; galović, pers. comm.), and the presence of supposedly marine elements in dinocyst associations (sütő-szentai, 1991; bakrač, 1999, 2005; popescu et al., 2009), seem to suggest that marine connections were not fully severed. a benthic fauna of molluscs and ostracods was almost fully endemic, refl ecting the persistent occurrence of a brackish lacustrine environment (müller et al., 1999). geologia croatica 65/2geologia croatica 210 during the late congeria rhomboidea biochron, ca. 6.5 ma, delta progradation from the northwest almost completely fi lled up the western part of the basin. only the drava (slavonija), and the sava depressions remained subaqueous in the western pannonian basin. as subsidence continued, the accommodation space on dry land was fi lled with fl uvial, terrestrial deposits. the deep sub-basins became gradually shallower as turbidites were deposited in the central parts of the depressions. a deep lacustrine environment was restricted to what is presently southeast hungary, northeast croatia and northern serbia. the endemic mollusc and ostracod faunas of lake pannon fl ourished, and migrated probably episodically into the eastern paratethys during the pontian, via an outfl ow of the lake (müller et al., 1999). during the pliocene, depositional basins in the sw part of the pannonian basin disintegrated into many small lakes (lučić et al., 2001), and lignite seams are frequent. 3. material and methods this work is based on outcrop study, in contrast to most other studies which are based on subsurface data. surface sediment samples were collected at 28 outcrops during the research project entitled “basic geological map of republic croatia 1: 50000”. sampling density was adjusted to the thickness of the layers with the same lithological and palaeontological characteristics. each change was sampled, and 98 samples were prepared. standard palynological processing techniques were used to extract the organic matter. the samples were treated with cold hcl (15%) and hf (40%), removing carbonates and silica. heavy liquid (zncl2, s.g. 2,1kg/l) was used to separate the organic matter from the undissolved inorganic components. the residue obtained was sieved through a 20-µm sieve, and palynological slides were prepared using glycerin gelatin as the mounting medium. the samples were not oxidized at any stage. analysis of palynological slides was performed under the light microscope combined with the interference contrast, resulting in identifi cation of 88 palynomorph taxa. a fl uorescence technique was used to distinguish in situ forms from reworked palynomorphs. each slide was counted for 200 palynomorphs for the purpose of quantitative analysis. important species are illustrated in pl. 1-2. dinocyst taxonomy is in accordance with that cited by lentin & williams (1998). 4. palynological results palynomorphs are generally well preserved in the studied samples. dinocysts dominate the assemblages, but some samples are dominated by prasinophyte phycomas or sporomorphs (spores and pollen). 4.1. palynological zonation the most consistent and characteristic dinocyst events have been selected to establish nine palynomorph zones, as defi ned below. the defi nitions of the zones are based on the fi rst occurrence (fo), last occurrence (lo), fi rst and last common occurrence (fco, lco) of one or more taxa of palynomorphs (fig. 2). the presented palynological zonal scheme (based on organic-walled phytoplankton – dinocysts and prasinophyte phycomas) for the middle and late miocene in the croatian part of central paratethys, was calibrated against macrofossil and microfossil distribution. 4.1.1. cribroperidinium tenuitabulatum zone (cte) defi nition: the upper boundary is the lo of cribroperidinium tenuitabulatum. the lower boundary is not defi ned because of the lack of deposits (styrian hiatus). characteristics: cribroperidinium tenuitabulatum in association with lingulodinium machaerophorum, cleistosphaeridium placacanthum, labyrinthodinium truncatum, tuberculodinium vancampoae, spiniferites spp. and cousteaudinium aubryae. common for ms are heterotrophic protoperidinoid cysts, e.g. selenopemphix and lejeunecysta indicating volcanically induced nutrifi cation. (pl. 1, figs. 31–36) calibration: lower lagenid zone and upper lagenid zone of grill (1943), nn4-nn5 (martini, 1971). correlation: central paratethyan cribroperidinium tenuitabulatum assemblage zone (jiménez-moreno et al., 2006), mediterranean tgo, ise and ltr zones (zevenboom, 1995), and to a certain extent, the eastern united states dn4 zone (de verteuil & norris, 1996). age: early badenian (langhian) – middle miocene. type section: čučerje – i (čuč-i) and vejalnica – iii (vej-iii). 4.1.2. unipontidinium aquaeductum zone (uaq) defi nition: the interval from the lo of cribroperidinium tenuitabulatum to the lco of unipontidinium aquaeductum. characteristics: a very rich and diverse phytoplankton assemblage composed of offshore dinocysts including; batiacasphaera micropapillata, batiacasphaera sphaerica, unipontidinium aquaeductum, nematosphaeropsis lemniscata, impagidinium patulum in co-occurrence with nearshore dinocysts; spiniferites ramosus, melitasphaeridium choanophorum, operculodinium centrocarpum, operculodinium crassum, operculodinium israelianum, operculodinium wallii, lingulodinium machaerophorum, polysphaeridium zoharyi, cleistosphaeridium placacanthum, spiniferites pseudofurcatus, labyrinthodinium truncatum, tuberculodinium vancampoae. (pl. 1, figs. 26–29) calibration: spiroplectammina zone, nn5-nn6. correlation: central paratethyan unipontidinium aquaeductum interval biozone (jiménez-moreno et al., 2006), mediterranean uaq zone (zevenboom, 1995), and to a certain extent eastern the united states dn5 zone (de verteuil & norris, 1996). age: badenian (late langhian – earliest serravallian) – middle middle miocene. bakrač et al.: middle and late miocene palnological biozonation of the south-western part of central paratethys (croatia) geologia croatica 211 type section: laz stubički – ii (lst-ii), zajezda – i (zaj-i). 4.1.3. cleistosphaeridium placacanthum zone (cpl) defi nition: the interval from the lco of unipontidinium aquaeductum to the lco of cleistosphaeridium placacanthum. characteristics: along with the most characteristic cleistosphaeridium placacanthum, there are also nearshore dinocysts including; spiniferites ramosus, melitasphaeridium choanophorum, operculodinium centrocarpum, operculodinium israelianum, lingulodinium machaerophorum, polysphaeridium zoharyi, hystrichosphaeropsis obscura. (pl. 1, fig. 30) calibration: bulimina – bolivina zone, nn6. correlation: the central paratethyan cerebrocysta poulsenii assemblage zone (jiménez-moreno et al., 2006); lower part of the hpo zone (zevenboom, 1995); figure 2: range chart of the stratigraphically indicative dinofl agellate cysts used in this study. geologia croatica 65/2geologia croatica 212 and to some extent with the upper part of the eastern united states dn5 zone (de verteuil & norris, 1996). age: late badenian (early serravallian) – middle miocene. type section: našice cementara – i (nac-i), jurjevčani – ii (jur-ii). 4.1.4. polysphaeridium zoharyi – lingulodinium machaerophorum zone (pzo-lma) defi nition: the open marine environment of the zone is chara cterized by the relatively diverse dinocyst assemblage, of which the most common forms are euryhaline dinocysts poly sphaeridium zoharyi and lingulodinium machaerophorum. restricted environments of this zone are recognized by a high proportion of prasinophycean genera. characteristics: along with abundant polysphaeridium zoharyi and lingulodinium machaerophorum of the open marine environment, occurrences of cleistosphaeridium placacanthum, hystrichokolpoma cinctum, operculodinium crassum, and melitasphaeridium choanophorum were also recorded. restricted environments are dominated by prasinophyte phycomas including; tytthodiscus mecsekensis, hida sia racemosa, hidasia rugosa, cymatiosphaera miocaenica, cymatiosphaera pseudoundulata and cymatio sphaera spinosa magna. in the upper part of the zone, endemic spiniferites bentorii budajenoensis occurred. (pl. 1, figs. 20–25) calibration: anomalinoides dividens zone; ervilia zone, nn7. correlation: the open marine environments of the zone correlate with the central paratethyan cleistosphaeridium placacanthum assemblage zone (jiménez-moreno et al., 2006); to a lesser extent, the mediterranean hpo zone (zevenboom, 1995) and the eastern united states dn6 zone (de verteuil & norris, 1996), while the restricted environment part correlates with spiniferites bentorii budajenoensis (sütő-szentai,1988). age: sarmatian (middle and late serravallian) type section: našice cementara – i (nac-i), jurjevčani – i (jur-i), laz stubički – i (lst-i), našice cementara – ii (nac-ii), kostanjek – i (kst-i). 4.1.5. mecsekia ultima – spiniferites bentorii pannonicus zone (mul-spa) defi nition: the fco to lco of mecsekia ultima in a restricted environment, and from the fo of spiniferites bentorii pannonicus to the fo of spiniferites bentorii oblongus in the hydrographically unstable environment. characteristics: prasinophyte algae mecsekia ultima, mecsekia spinosa, mecsekia spinulosa and mecsekia incrassata dominate the phytoplankton assemblages in the restricted lagoon and shallow water carbonate facies. the endemic dinocyst spiniferites bentorii pannonicus was observed in the hydrographically unstable environment. calibration: lymnocardium praeponticum acrozone and cenozone radix croatica – lymnocardium plicataeformis – gyraulus praeponticus (vrsaljko, 1999). (pl. 1, figs. 14–19) correlation: central paratethyan mecsekia ultima zone – spiniferites bentorii pannonicus zone (sütő-szentai,1988). age: early early pannonian s.l. type section: krapinske toplice – i (krt-i), kostanjek – i (kst-i), našice cementara – ii (nac-ii). 4.1.6. spiniferites bentorii oblongus zone (sob) defi nition: the interval from the fo of spiniferites bentorii oblongus to the fco of pontiadinium pecsvaradensis. characteristics: these are the most diverse and rich assemblages in the early pannonian, characterized by spiniferites bentorii oblongus, spiniferites bentorii pannonicus, virgodinium asymmetricum, chytroeisphaeridia cariacoensis and chytroeisphaeridia hungarica. (pl. 1, figs. 8–13) calibration: spiniferites bentorii oblongus biochron – ca. 10.8 ma (magyar et al., 1999b), and congeria banatica – lymnocardium gorjanovici – gyraulus tenuistriatus cenozone (vrsaljko, 1999). correlation: central paratethyan spiniferites bentorii oblongus zone (sütő-szentai, 1988). age: middle early pannonian s.l. type section: kostanjek – i (kst-i), našice cementara – ii (nac-ii), pušća – i (pšć-i). 4.1.7. pontiadinium pecsvaradensis zone (ppe) defi nition: the interval from the fo of pontiadinium pecsvaradensis to the fo of spiniferites bentorii coniunctus characteristics: proximate forms from distal, open environments represented by p o ntiadinium pecsvaradensis, impagidinium spongianum, virgodinium baltesii, and virgodinium asymmetricum and the rare mediterranean dinocysts achomosphaera, spiniferites and operculodinium. (pl. 1, figs. 1–7) calibration: congeria czjzeki – lymnocardium winkleri – gyraulus tenuistriatus cenozone (vrsaljko, 1999). correlation: central paratethyan pontiadinium pecsvaradensis zone (sütő-szentai, 1988). chronostratigraphic age: late early pannonian s.l. type section: našice cementara – ii (nac-ii), pušća – i (pšć-i), požarkovec – i (pož-i). 4.1.8. spiniferites validus zone (sva) defi nition: the interval from the fo to the lco of spiniferites validus in proximal, or from the fo of spiniferites bentorii coniunctus to the fo of galeacysta etrusca in distal environments. characteristics: a diverse and rich dinocyst assemblage dominated by spiniferites bentorii coniunctus, spiniferites balcanicus, spiniferites maisensis, spiniferites virgulaeformis, achomosphaera andalousiensis, nematosphaeropsis bicorporis, spiniferites bentorii coniunctus, spiniferites cf. bakrač et al.: middle and late miocene palnological biozonation of the south-western part of central paratethys (croatia) geologia croatica 213 bentorii (membranous forms), spiniferites bentorii oblongus, spiniferites cf. paradoxus, spiniferites ramosus, spiniferites virgulaeformis, chytroeisphaeridia cariacoensis, virgodinium asymmetricum, virgodinium baltesii, virgodinium transdanuvianum, pontiadinium inequicornutum, pontiadinium pecsvaradensis. proximal environments are dominated by spiniferites validus, virgodinium pelagicum, chytroeisphaeridia sp., impagidinium globosum, impagidinium spongianum "type b", and green algae botryococcus braunii. (pl. 2, figs. 21–39) calibration: “abichi beds”. correlation: spiniferites balcanicus main zone (sütőszentai, 1989); spiniferites validus zone (magyar et al., 1999b). age: early late pannonian s.l. type section: požarkovec – i (pož-i), tolovajčići – ii (tol-ii). bekini – ii (bek-ii). pušća – i (pšć-i), požarkovec – i (pož-i), mirti – i (mir-i), andraševec – i (and-i), malunje – i (mal-i). 4.1.9. galeacysta etrusca zone (get) defi nition: the zone is defi ned by the dominance of impagidinium globosum in proximal, and by galeacysta etrusca in more distal environments. characteristics: proximal environments are characterized by the proximate dinocysts with thicker walls, e.g. impagidinium globosum, virgodinium asymmetricum, chytroeisphaeridia tuberosa, brigantedinium sp., impagidinium spongianum "type b", virgodinium pelagicum, and spiniferites validus. in distal environments, galeacysta etrusca, spiniferites balcanicus, spiniferites maisensis, spiniferites virgulaeformis and spiniferites cruciformis dominate (pl. 2, figs. 1–20). calibration: “rhomboidea beds” correlation: interval zone dinofl agellata – zygnemataceae / zone mougeotia laetevirens (sütő-szentai, 1988); galeacysta etrusca zone (magyar et al., 1999b); galeacysta etrusca interval zone (zevenboom, 1995); age: late late pannonian s.l. type section: selnica – i (sel-i), bekini – ii (bek-ii), tolovajčići – ii (tol-ii), vrbovo – i (vrv-i), našice cementara – iii (nac-iii), krajačić – i (kra-i). 5. discussion 5.1. palaeoecology of the organic-walled phytoplankton dinofl agellate cysts are sensitive environmental indicators, and are therefore of potential use in palynological analysis of environmental conditions. several studies (e.g., wall et al., 1977; dale, 1996) have indicated that four types of environmental signals can be deduced from recent cyst distributions: (1) surface water temperature, (2) a coastal-oceanic distribution, (3) salinity, and (4) productivity. however, it is important to keep in mind that cyst thanatocoenosis may not always correspond to theca biocoenosis. the dinocyst record can be a mixture of cysts transported by currents and cysts derived from theca, living in the water mass above the bottom where the cysts are fi nally accumulated. relative sea level fl uctuations in neritic settings are usually refl ected in the varying abundance of taxa, which typically occur in restricted marine or inner neritic water masses versus those that characteristically occur in outer neritic waters (brinkhuis, 1994; jaramillo & oboh-ikuenobe, 1999). high abundance of protoperidinoid cysts (selenopemphix and lejeunecysta) were used to indicate phases of enhanced nutrient availability, (by either stronger terrigenous input or volcanic activity). studies on modern dinofl agellates have shown that oxygen availability exerts a strong control on cyst germination, with anaerobic conditions completely inhibiting the excystment of most taxa (anderson et al., 1987). pross (2001) proposed a model for thalassiphora pelagica, characterized by a wing-like membrane on the dorsal side of most specimens, which may have facilitated a holoplanktic life cycle in contrast to most other cyst-producing dinofl agellates. this may also apply to galeacysta etrusca and unipontidinium aquaeductum. oxygen depletion on the sea fl oor prohibits excystment and causes dinocyst diversity to decrease. thalassiphora pelagica (or s. balcanicus in our samples) is not affected because its excystment occurs in the water column. decreasing temperatures may be responsible for changes in the dinocyst assemblage as can be seen through zone cte, including the disappearance of cribroperidinium tenuitabulatum (also recognized by jiménez-moreno et al., 2006). karpatian and early badenian fl oras refl ect the miocene climate optimum (mco) as they are extremely rich in thermophilous elements. a progressive decrease in thermophilous elements immediately follows, and fl oral diversity occurred during the late badenian and sarmatian. this has been interpreted as climatic cooling during the “monterey cooling event“, which occurred at 14.2 ma, correlated with the increase in development of the east antarctic ice sheet (jiménez-moreno et al., 2005). morphological changes in dinocysts as a result of low salinity or other environmental stress were fi rst described by wall et al. (1973) based on the holocene material from the black sea. they observed that in low-salinity environments, as compared to normal-salinity assemblages, an increased number of dinocysts with reduced processes, variations in septal development and cruciform (rather than rounded) endocysts occur. moreover, changes in archeopyle formation have also been attributed to salinity fl uctuations (wall et al., 1977). the hypothesis that salinity was a factor in determining process length in various chorate dinocysts has been corroborated by studies on lingulodinium machaerophorum/ l. polyedrum (nehring, 1994), operculodinium centrocarpum (e.g., de vernal et al., 1989; matthiessen & brenner, 1996) and spiniferites spp. (e.g., dale, 1996; ellegaard, 2000; lewis et al., 1999, 2003). the suggestion that a cruciform endocyst may indicate the infl uence geologia croatica 65/2geologia croatica 214 of a low-salinity environment has also been corroborated by dale (1996) and a study on cruciform spiniferites cysts from a lacustrine setting in northern greece (kouli et al., 2001). kouli et al. (2001), recorded s. cruciformis together with the freshwater species gonyaulax apiculata in lacustrine sediments, suggesting that s. cruciformis is a fre shwater species and that any occurrences in (brackish) marine environments, with the exception of specimens with strongly reduced ornamentation, may be due to transportation, shortlived freshwater surface conditions and/or tolerance of the species to brackish conditions. mudie et al. (2002), also use s. cruciformis to reconstruct brackish water environments and freshwater input from glacial lakes. an increase of outer neritic to oceanic taxa, (such as species of nematosphaeropsis and impagidinium) was interpreted as indicating a sea level rise, whereas increasing abundances of neritic to coastal taxa were interpreted as denoting a regressive trend. the majority of dinocyst range bases were positioned in transgressive systems tracts (ppe zone), which can probably be attributed to a widening of shelf dinofl agellate habitats, fostering the evolution of new dinofl agellate taxa. accordingly, range tops were predominantly discovered in highstand systems tracts (cpl zone). the low diversity of microplankton a s sociations may be indicative of stressed, restricted conditions with often unstable salinities (gorin & steffen, 1991). prasinophytes are attributed as “disaster species” (tappan, 1980) being most abundant in the absence of other plankton, suggesting ecological conditions which cannot support the development of other phytoplankton communities. however, the abundance of prasynophyte phycomata is at least partly a consequence of reduced dinocyst production in permanently stratifi ed basins, and does not refl ect the original phytoplankton assemblage, i.e. phytoplankton dynamics (tyson, 1995). phycomata abundance indicates therefore, hydrographic stability of stratifi ed basins where motile dinofl agellate assemblages participate in the overall composition of phytoplankton assemblages much more than is actually recorded in the palynological record as dinocysts. these ecological conditions usually include low temperature, enhanced productivity and a stratifi ed water column, exhibiting brackish or lowsalinity surface waters overlying low oxygen to anoxic bottom waters (tyson, 1987; tyson, 1995). dominance of prasinophyte algae has been recorded from some restricted lagoon and shallow water carbonate facies (tyson, 1995). this happened in the investigated area during the middle badenian and sarmatian – earliest pannonian. 5.2. zonation based on the organic-walled phytoplankton palynological characterization of 28 lithostratigraphic columns of the investigated area, as well as the known stratigraphic relationships of paratethyan miocene species (rögl, 1998; magyar et al., 1999b; hudáčková et al., 2000; kováč et al., 2004) facilitated compilation of a palynological zonation of the middle and late miocene which was correlated with the palynological zonation of contemporaneous deposits in the mediterranean realm (powell, 1986a,b,c; zevenboom, 1995; jiménez-more no et al., 2006; sütő-szentai, 1 988, 1991). unfortunately, the geochronology of the miocene in croatia has not yet been established. therefore, the age assignment is mostly based on biostratigraphy. at present, the main criteria for the biostratigraphic zonation of miocene deposits are characteristic molluscs due to their relatively effective usage already established during fi eld work. however, the distribution of the molluscs depends on environmental conditions and they react relatively slowly to global changes. in addition, their occurrence is usually relatively rare. in contrast, the response of organic walled phytoplankton to ecological change as well as their spread to new living space is much faster. furthermore, organic walled phytoplanktons are often abundant even in small samples. for regional correlation, the recognition of neogene biohorizons which contain cosmopolitan dinocysts (fco and lco) is very important, although this may be hampered due to environmental change causing variations in diversity and composition of dinosporin assemblages (stover et al., 1996). these relationships are best revealed by the divergent organic walled phytoplankton developments as paratethys began to separate from tethys during the sarmatian. formation of the pannonian basin resulted in endemism of organic walled phytoplankton species. consequently, the middle miocene marine assemblages are regionally correlated, while the late miocene of paratethys is limited and mostly depends on other biostratigraphy. fortunately, the paratethyan late miocene is characterized by two short lasting events indicating connections with the tethyan realm which facilitates the correlation between these two areas. correlation is based on palynological zones from several authors. zevenboom (1995) presented the palynological zonation of several micropalaeontologically and magnetostratigraphically defi ned miocene type sections in italy. jimenez-moreno et al. (2006), documented palynological zones for the badenian and the lower part of the sarmatian, based on the material from austrian outcrops and a hungarian borehole. de verteuil & norris (1996) proposed the zonation of miocene deposits from the middle atlantic coastal plain. the boundary between the cribroperidinium tenuitabulatum and unipontidinium aquaeductum zones is marked by the disappearance of cribroperidinium tenuitabulatum, and a decrease in the thermophilous element (labyrinthodinium truncatum, tuberculodinium vancampoae). this was interpreted as a response to climatic cooli ng during the “monterey cooling event” correlated with the increase in development of the east antarctic ice sheet (jiménez-moreno et al., 2006). jiménez-moreno et al. (2006) proposed the cleistosphaeridium placacanthum zone for the lower sarmatian, however it seems more likely that polysphaeridium zoharyi and lingulodinium machaerophorum are more characteristic due to local environmental conditions. this may be deduced from their material as it can be seen that polysphaeridium sp. a and lingulodinium machaerophorum are very common bakrač et al.: middle and late miocene palnological biozonation of the south-western part of central paratethys (croatia) geologia croatica 215 figure 3: palinostratigraphic zonation and correlation with other biozones based on gradstein et al. (2004), piller et al. (2007), showing the dinocyst zones of de verteuil & norris (1996), zevenboom (1995), sütő-szentai (1988), magyar et al. (1999a), jiménez-moreno et al. (2006) and the proposed zonation correlated with zones proposed by papp (1951), šikić et al. (1979), martini (1979). forms in their cpl zone. their ranges extend from the older strata, and their presence has environmental signifi cance. polysphaeridium zoharyi has been recorded from subtropical and tropical regions, generally in coastal sites, near upwelling cells and river mouths. the highest relative abundances have been observed in the tropical low-salinity areas, where this species can dominate the assemblages (marret & zonneveld, 2003). lingulodinium machaerophorum can be considered to be a temperate to tropical, coastal euryhaline species. an increased number of specimens with reduced process lengths can be observed related to low or high salinity. blooms of l. polyedrum can be related to high nutrient input and warm, stratifi ed surface water conditions. it is distributed within a very broad salinity range and has been recorded from brackish to fully marine environments (marret & zonneveld, 2003). lingulodinium machaerophorum has its lco in the pannonian basin during this zone. we think that it is more proper to extend the polysphaeridium zoharyi – lingulodinium machaerophorum zone up to the end of the sarmatian. lingulodinium machaerophorum could be found in the open environment, while cymatiosphaera miocaenica dominated the restricted environment. due to fl uctuations in sea level, facies migrations are common. so, deposits with prasinophytes cymatiosphaera miocaenica and mecsekia incrassata may interfi nger with facies dominated by dinocysts. this could also explain why sütőszentai (2005) placed the m. ultima zone between the s.b. pannonicus – l. machaerophorum and s.b. pannonicus zones. sütő-szentai (2005) placed the s.b. panno nicus – l. machaerophorum zone above the late sarmatian s.b. budajenoensis – m. incrassata zone. the as sem blages were most likely contemporaneous. however, the “younger” assemblage existed within a relatively distal, more open environment characterized by conditions which continued from the sarmatian times, enriched with some new pannonian incomers. the assemblage characteristic of this zone was seen in the kostanjek-i (kst-i) (fig. 1b) column just below the “croatica beds”. on the basis of the ostracods and diatoms, these deposits belong to the latest sarmatian, which justifi es the placement of the boundary between the sarmatian and pannonian above the s. b. pannonicus – l. machaerophorum zone. the taxon s.b. budajenoensis is questionable since there is no description, and according to sütő-szentai (pers. comm.), the difference between s.b budajenoensis and s.b. pannonicus is small, if any, suggesting that they may represent the same species, i.e. morphologically altered s. bentorii with a much more reduced processes as a consequence of environmental changes due to decreased salinity. at that time, the species l. machaerophorum occurs in high abundance for the last time in the pannonian basin. theregeologia croatica 65/2geologia croatica 216 plate 1 1 pontiadinium pecsvaradensis sütő-szentai 1982, pšć-i 5/1, ventral view at low focus. 2 pontiadinium pecsvaradensis sütő-szentai, and-ii 3-1, dextro-lateral view at high focus. 3 pontiadinium pecsvaradensis sütő-szentai, and-ii 3-1, dextro-lateral view at high focus in fl uorescence illumination. 4 impagidinium spongianum sütő-szentai 1985 "type a", nac-ii 94/1, ventral view at low focus. 5 impagidinium spongianum sütő-szentai 1985 "type a", nac-ii 94/1, ventral view at high focus on archeopyle. 6 impagidinium spongianum sütő-szentai 1985 "type a", sam-i 1-12, dextro-lateral view at low focus in interference contrast illumination. 7 virgodinium asymmetricum sütő-szentai 2010, sam-i 1-12, sinistro-lateral view at low focus in interference contrast illumination. 8 spiniferites bentorii pannonicus sütő-szentai 1986, nac-ii 81/1, sinistro-lateral view. 9 spiniferites bentorii oblongus sütő-szentai 1986, nac-ii 81/1, dextro-lateral? view. 10 spiniferites bentori oblongus sütő-szentai 1986, mir-i 4/6, dextro-dorsal? view. 11 achomosphaera andalousiensis jan du chêne 1977, nac-ii 65/1, ventral view. 12 spiniferites bentorii pannonicus sütő-szentai 1986, nac-ii 81/1, dextro-lateral view. 13 impagidinium spongianum sütő-szentai 1985 "type a", nac-ii 65/1, sinistro-lateral view. 14 mecsekia ultima sütő-szentai 1982, nac-ii 7/1. 15 mecsekia ultima sütő-szentai 1982, nac-ii 7/1. 16 mecsekia ultima sütő-szentai 1982, kst-i 10, interference contrast illumination. 17 spiniferites bentorii pannonicus sütő-szentai 1986, kst-i 36, sinistro-lateral view. 18 spiniferites bentorii pannonicus sütő-szentai 1986, kst-i 36, dextro-lateral view. 19 spiniferites bentorii pannonicus sütő-szentai 1986, kst-i 48. 20 lingulodinium machaerophorum (deflandre & cookson, 1955) wall 1967, nac-ii 5/1, lateral view. 21 polysphaeridium zoharyi (rossignol 1962) bujak et al. 1980, lst-i 3/1, lateral view. 22 mecsekia spinosa hajós 1966, nac-ii 3/7. 23 cymatiosphaera miocaenica sütő-szentai 1964,nac-ii 3/7. 24 spiniferites bentorii budajenoensis sütő-szentai 1986, kst-i 6, view uncertain. 25 spiniferites bentorii budajenoensis sütő-szentai 1986, kst-i 6, dextro-lateral view. 26 unipontidinium aquaeductum (piasecki 1980) wrenn 1988, lst-ii 6/1, ventral view at high focus on archeopyle. 27 nematosphaeropsis lemniscata bujak 1984, lst-ii 6/1, high focus on trabeculae. 28 melitasphaeridium choanophorum (deflandre & cookson 1955) harland & hill 1979, lst-ii 6/1, oblique apical view. 29 tuberculodinium vancampoae (rossignol 1962) wall 1967, lst-ii 6/3. 30 cleistosphaeridium placacanthum deflandre & cookson 1955, lst-ii 6/1, apical view at low focus. 31 cribroperidinium tenuitabulatum (gerlach, 1961) helenes, 1984, čuč-i/1. 32 cousteaudinium aubryae de verteuil & norris, 1996, vej-iii/5. 33 batiacasphaera sphaerica stover, 1977, čuč-i/1. 34 habibacysta tectata head et al., 1989, čuč-i/1. 35 operculodinium piaseckii strauss & lund, 1992, čuč-i/1. 36 lejeunecysta sp., čuč-i/1. scale bar is 25 mm. fore, it is considered that the ecozone pzo-lma should be extended up to the end of the sarmatian since l. machaerophorum occurs continuously in open environments while c. miocaenica consistently occurs in more restricted environments. due to eustatic fl uctuations, the facies migrated which may have caused the prasinophytes c. miocaenica and m. incrassata, (abundant in restricted, quiet, stratifi ed and brackish environments), to be located together in deposits with assemblages dominated by the dinosporin cysts of more open environments. these relationships were recorded in the našice cementara-ii (nac-ii) (fig. 1c) column where layers dominated by dinosporin cysts alternate with layers dominated by prasinophytes, suggesting cyclic alteration of stratifi ed with hydrographically unstable water columns. in the earliest pannonian, salinity was so low that the environment became oligohaline, and locally even fresh. such environmental conditions enabled the expansion of endemic species. ecological conditions were unfavorable for dinofl agellates, which is evidenced by the absence of dinocysts in these sediments. consequently, prasinophyte algae dominate the phytoplankton assemblages. in our opinion, sütő-szentai (1988) presented the best zonation for the pannonian. the spiniferites bentorii zone (sütő-szentai, 1988), subdivided into the spiniferites bentorii pannonicus, spiniferites bentorii oblongus and pontiadinium pecsvaradensis subzones, indicates an early pannonian age, while the spiniferites validus zone, subdivided into the spiniferites validus and spiniferites paradoxus subzones, indicates a late pannonian age. later, sütő-szentai (1991; 1994) presented a more detailed zonation described as the spiniferites balcanicus main zone, which is divided into the spiniferites validus and spiniferites bentorii coniunctus – spiniferites paradoxus zones, and remained as late pannonian in age. magyar et al. (1999b) correlate dinofl agellate zones with other biozones and suggested that their new spiniferites paradoxus zone is of early pannonian age. in the investigated area under consideration, this is not the case, since the spiniferites bentorii coniunctus – spiniferites paradoxus zones are contemporaneous with the spiniferites validus zone from a more proximal environment. therefore, we joined these two zones into one zone; the spiniferites validus zone. nematosphaeropsis sp. and membranous forms of spiniferites bentorii indicate water-level rise and a distal environment. in the upper part of the pontiadinium pecsvaradensis zone, a few mediterranean dinocyst species (acho mosphaera, spiniferites and operculodinium) were re cog nized, indicating communication between the mediterranean and paratethys at that time. also, signifi cant fi ndings of the dinocysts spiniferites cruciformis and galeacysta etrusca most bakrač et al.: middle and late miocene palnological biozonation of the south-western part of central paratethys (croatia) geologia croatica 217 likely represent their oldest occurrence indicating that they evolved in the pannonian basin. the southern shoreline, running parallel to the sava river along the northern foot of the dinarides, changed very little during the lifetime of lake pannon. rare and sporadic fi ndings of polyhaline nannofossils (kollányi, 2000; galović, pers. comm.), and the presence of supposedly marine elements in dinocyst associations (sütő-szentai, 1991; bakrač, 1999, 2005; popescu et al., 2009), seem to suggest that marine connections were not fully severed. moreover, the “lago mare” brackish fauna contained late messinian endemics, suggesting that their origin is related to the oldest late miocene–pannonian paratethyan biota (popov et al., 2006). the endemic mollusc and ostracod faunas of lake pannon fl ourished, and migrated, probably episodically into the eastern paratethys during the pontian via an outfl ow of the lake (müller et al., 1999). correlation with mediterranean/global chronostratigraphy is based on scattered biostratigraphic tie points, particularly those of calcareous nannoplankton and planktonic foraminifera. no boundary stratotypes are defi ned for any of the miocene central paratethyan (piller et al., 2007). based on the dinocyst diversity and abundance, four maximum fl ooding surfaces during the middle and late miocene were recognized in the south-western parts of the central paratethys, and are subject of our recent research. geologia croatica 65/2geologia croatica 218 plate 2 1 achomosphaera andalousiensis jan du chêne 1977; kra-i 1/6, ventral view at high focus on trabeculae. 2 achomosphaera andalousiensis jan du chêne 1977; kra-i 1/6, ventral view at mid focus. 3 spiniferites cruciformis wall & dale 1973; kra-i 1/6, view uncertain. 4 pontiadinium inequicornutum baltes 1971; kra-i 1/6, lateral view. 5 pyxidinopsis psilata (wall & dale 1973) head 1994; kra-i 1/7, dorsal view at low focus on archeopyle. 6 pyxidinopsis psilata (wall & dale in wall et al., 1973) head, 1994; kra-i 1/3, scanning electron micrographs. 7 impagidinium (?) sp 1 sensu corradini & biffi, 1988; išć-i 19/1. 8 galeacysta etrusca corradini & biffi 1988; skops 31b-2. 9 galeacysta etrusca corradini & biffi 1988; išć-i 19-1. 10 galeacysta etrusca corradini & biffi 1988; kra-i 1/6, ventral view. 11 galeacysta etrusca corradini & biffi 1988; skops 31b-2. 12 tectatodinium sp.; skops 31b-0. 13 impagidinium spongianum sütő-szentai, 1985; išć-i 19/1, lateral view at high focus in interference contrast illumination. 14 achomosphaera andalousiensis jan du chêne 1977; kra-i 1/3, ventral – dextral-lateral view at high focus on trabeculae. 15 achomosphaera andalousiensis jan du chêne 1977; kra-i 1/3, ventral – dextral-lateral view at mid focus on surface. 16 achomosphaera andalousiensis jan du chêne, 1977; kra-i 1/3, scanning electron micrographs. 17 spiniferites cruciformis wall & dale 1973; kra-i 1/3, view uncertain. 18 pontiadinium inequicornutum baltes 1971; kra-i 1/3, lateral view. 19 impagidinium globosum sütő-szentai 1985, išć-i 19/1, lateral view at high focus in fl uorescence illumination. 20 impagidinium globosum sütő-szentai 1985, išć-i 19/1, lateral view at high focus. 21 pontiadinium inequicornutum baltes 1971; tol-ii 1/1, ventral – sinistro-lateral view. 22 pontiadinium inequicornutum baltes 1971; išć-i 18-1. 23 spiniferites validus sütő-szentai 1982; tol-ii 1/1, dextro-lateral? view. 24 spiniferites validus sütő-szentai 1982; tol-ii 1/1, dextro-lateral? view. 25 spiniferites validus sütő-szentai 1982; tol-ii 1/1, fragment. 26 spiniferites validus sütő-szentai 1982; tol-ii 1/1, dextro-lateral? view. 27 spiniferites validus sütő-szentai 1982; kra-i 1/3, scanning electron micrographs. 28 spiniferites balcanicus (baltes 1971) sütő-szentai 1988; mir-i 4/10, sinistro-lateral view at high focus. 29 spiniferites balcanicus (baltes 1971) sütő-szentai 1988; mir-i 4/10, sinistro-lateral view at mid focus. 30 spiniferites balcanicus (baltes 1971) sütő-szentai 1988; mir-i 4/10, sinistro-lateral view in fl uorescence illumination. 31 achomosphaera andalousiensis jan du chêne 1977; and-i 1/2, view uncertain. 32 millioudodinium pelagicum sütő-szentai 1990; mir-i 4–6. 33 spiniferites virgulaeformis sütő-szentai 1994; and-i 1/2, dorsal? view at mid focus. 34 nematosphaeropsis bicorporis sütő-szentai 1990, and-i 1–2. 35 nematosphaeropsis bicorporis sütő-szentai 1990; mal-i 1/1, ventral view at high focus on trabeculae. 36 nematosphaeropsis bicorporis sütő-szentai 1990; skops 37, antapical view at high focus on trabeculae. 37cf. spiniferites paradoxus (cookson & eisenack 1968) sarjeant 1970; skops 37, ventral view. 38 spiniferites bentorii (rossignol, 1964) wall & dale, 1970 (membranous form) mal-i 1/1, dextral-lateral view and pyrite grain in membrane. 39 spiniferites bentorii coniunctus sütő-szentai, 1990; kob-ii 3–7. scale bar is 25 mm. dinofl agellates are shown to be highly effective organisms for establishing the connection and/or isolation phases of various basins adjacent to the mediterranean. this is particularly true when comparing the vertical distribution of galeacysta etrusca and congeria molluscs at eraclea minoa. there, galeacysta etrusca was recorded in relative high sealevel deposits represented by diatomitic turbidites preceding the last gypsum bed, and in the arenazzolo formation, while congeria molluscs are present within the “lago mare” formation which corresponds to a relative lowering of sea-level. as congeria molluscs may develop in invading coastal lagoon environments, they are more signifi cant of local brackish conditions (possibly continuing after the invasion event) than galeacysta etrusca which precisely demarcates the exchange events at high sea-level between basins. connections between the pannonian and dacian basins during the late pannonian s.l. have long been considered to facilitate mutual exchange of the aquatic fauna. now it seems that this connection worked as a biogeographic fi lter which allowed primarily a one-way traffi c out of lake pannon towards the eastern paratethys (müller et al., 1999; popov et al., 2006). 6. conclusion palynological characterization of the middle and late miocene from the south-western parts of the pannonian basin in croatia allowed recognition of nine continuous palynological zones which were correlated with contemporaneous stra ta in the mediterranean. the early badenian (langhian) cribroperidinium tenuitabulatum (cte) zone is the oldest recognized zone of deeper and distal marine environments. the zone corresponds to the central paratethyan cte zone (jiménez-moreno et al., 2006), mediterranean tgo, ise and ltr zones (zevenboom, 1995), and to a certain extent, the eastern united states dn4 zone (de verteuil & norris, 1996). the middle badenian (late langhian – earliest serravallian) unipontidinium aquaeductum (uaq) zone also refl ects deeper and distal environments and it may be well corre lated with the central paratethyan uaq zone (ji ménez -moreno et al., 2006), mediterranean uaq zo ne (zevenboom, 1995), and to a certain extent, the eastern united states dn5 zone (de verteuil & norris, 1996). bakrač et al.: middle and late miocene palnological biozonation of the south-western part of central paratethys (croatia) geologia croatica 219 a late badenian (early serravallian) cleistosphaeridium placacanthum (cpl) zone is defi ned in a proximal, open marine environment. this zone correlates with the central paratethyan cpo zone (jiménez-moreno et al., 2006), lower part of the mediterranean hpo zone (zevenboom, 1995), and to some extent, the upper part of the eastern united states dn5 zone (de verteuil & norris, 1996). the sarmatian (middle and late serravallian) poly sphaeridium zoharyi – lingulodinium machaerophorum (pzolma) zone is recognized in open marine environments dominated by dinocysts and in restricted environments dominated by prasinophyte phycomas. the open environments of the zone corre late with the central paratethyan cte zone (ji ménez -moreno et al., 2006), to a small extent with the mediterranean hpo zone (zevenboom, 1995), and the eastern united states dn6 zone (de verteuil & norris, 1996), while restricted environments correlate with the spiniferites bentorii budajenoensis zone of sütő-szentai (1988). the pannonian basin experienced environmental changes during the earliest pannonian which were conducive for phytoplankton developments absolutely dominated by prasinophytes up to only few and very rare endemic dinocysts. accordingly, the earliest pannonian zone, comprising most of the “croatica beds” is assigned to the mecsekia ultima – spiniferites bentorii pannonicus (mul-spa) zone which is typical for local paratethyan environments, as well as the geologia croatica 65/2geologia croatica 220 mecsekia ultima zone and spiniferites bentorii pannonicus zone of sütő-szentai (1988), and may not be correlated with any tethyan zone. the spiniferites bentorii oblongus (sob) zone was defi ned within the lower part of the “banatica beds” of the middle part of the early pannonian s.l., and represents a correlative of the spiniferites bentorii oblongus zone of sü tő -szentai (1988). the late early pannonian s.l. pontiadinium pecsvaradensis (ppe) zone was recognized within the upper part of the “banatica beds” and may be correlated with the pontiadinium pecsvaradensis zone (sütő-szentai, 1988). the early late pannonian s.l. spiniferites validus (sva) zone was defi ned within the “abichi beds”. this zone correlates with the spiniferites balcanicus main zone of sütőszentai (1989), and the spiniferites validus zone of magyar et al. (1999b). the late late pannonian s.l. galeacysta etrusca (get) zone was defi ned in the “rhomboidea beds”, and may be correlated with the interval zone dinofl agellata – zygnema taceae / mougeotia laetevirens zone of sütő-szentai (1988, 2011), as well as the galeacysta etrusca zone of ma g yar et al. (1999b), and the get zone of zevenboom (1995). after isolation of paratethys during the sarmatian, two transgressions are documented: the fi rst one in the late early pannonian, when mediterranean dinofl agellates migrated into the pannonian basin, and the second one in the late pannonian, when endemic paratethyan taxa migrated into the mediterranean. based on the dinocyst diversity and their abundance, four maximum fl ooding surfaces (mfs) were recognized, and are the subject of recent research. acknowledgement the present investigation is part of the basic investigation supported by the croatian geological survey, department of geology, and ministry of science, education and sports projects no. 181-1811096-1093: “basic geological map of the republic of croatia 1:50 000”, and no. 119-19512931162: “evidence of biotic and abiotic changes in palaeoenvironments”. the authors wish to thank colleagues mirjana miknić, valentina hajek-tadesse, otto basch, mato brkić, davor vrsaljko, davor pavelić, radovan avanić, ines galović and marijan kovačić for their help in the fi eld, as well as providing analysis and constructive discussions which led to substantial improvements of the manuscript. we are grateful to anonymous reviewers for their valuable and helpful reviews. references anderson, d.m., taylor, c.d. & armbrust, e.v. (1987): the effects of darkness and anaerobiosis on dinofl agellate cyst germination.– limnol. oceanogr., 32, 340–351. avanić, r., pavelić, d., brkić, m., miknić, m. & šimunić, al. (1995): lapori i biokalkareniti vejalnice.– in: šikić, k. (ed.): geološki vodič medvednice. inst. za geol. istraž., ina-industrija nafte d.d., zagreb, 159–164. bakrač, k. (1999): palinologija pontskih naslaga medvednice [palinology of pontian sediments from mt. medvednica – in croatian, with english summary].– unpubl. msc thesis, university of zagreb, 93 p. bakrač, k. (2005): palinološka karakterizacija naslaga srednjeg i gornjeg miocena jugozapadnog dijela panonskog bazena [palynology of the middle and upper miocene deposits from the south-western parts of the pannonian basin – in croatian, with english summary].– unpubl. phd thesis, university of zagreb, 173 p. bakrač, k., hajek-tadesse, v., miknić, m., grizelj, a., heći mović, i. & kovačić, m. (2010): evidence for badenian local sea level changes in the proximal area of the north croatian basin.– geol. croat., 63/3, 259–269. doi: 104154/gc.2010.21 báldi, t. (1980): the early history of the paratethys.– bulletin of the hungarian geological society, 110/3–4, 468–471. baltes, n. (1967): microfl ora from miocene salt-bearing formation of the pre-carpathian depression (rumania).– rev. palaeobot. palynol., 2, 183–194. baltes, n. (1969): distribution stratigraphique des dinofl agellés et des acritarches tertiaires en roumanie.– in: brönnimann, p. & renz, h.h. (eds.): 1st international conference on planktonic microfossils, 1967, e.j. brill, leiden, geneva, proceedings, 1, 26–45. biffi, u. & manum, s.b. (1988): late eocene-early miocene dinofl agellate cyst stratigraphy from the marche region (central italy).– boll. soc. geol. ital., 27/2, 163–212. brinkhuis, h. (1994): late eocene to early oligocene dinofl agellate cysts from the priabonian type-area (northeast italy): biostratigraphy and paleoenvironmental interpretation.– palaeogeogr. palaeocl., 107, 121–163. costa, l.i. & manum, s.b. (1988): the description of the interregional zonation of the paleogene (d1-d15) and the miocene (d16d20).– in: vinken, r. (eds.): the northwest european tertiary basin: results of the international geological correlation progra m me, project no. 124, geologisches jahrbuch, reiche a, 100, 321–330. ćorić, s., pavelić, d., rögl, f., mandic, o., vrabac, s., avanić, r. & vranjković, a. (2009): revised middle miocene datum for initial marine fl ooding of north croatian basins (pannonian basin system, central paratethys).– geol. croat., 62/1, 31–43. dale, b. (1996): dinofl agellate cyst ecology: modeling and geological applications.– in: jansonius, j. & mcgregor, d.c. (eds.): palynology: principles and applications. american association of stratigraphic palynologists foundation, dallas, 1249–1276. de vernal, a., goyette, c. & rodrigues, c.g. (1989): contribution palynostratigraphique (dinokystes, pollen et spores) á la connaissance de la mer de champlain: coupe de saint cezaire, québec.– can. j. earth. sci., 26, 2450–2464. de verteuil, l. & norris, g. (1996): miocene dinofl agellate strati graphy and systematics of maryland and virginia.– micropaleontology, 42, suppl., 1–172. ellegaard, m. (2000): variations in dinofl agellate cyst morphology under conditions of changing salinity during the last 2000 years in the limfjord, denmark.– rev. palaeobot. palynol., 109, 65–81. gorin, g.e. & steffen, d. (1991): organic facies as a tool for recording eustatic variations in marine fi ne-grained carbonates – example of the berriasian stratotype at berrias (ardèche, se france).– palaeogeogr. palaeocl., 85, 303–320. gradstein, f.m., ogg, j.g., smith, a.g., agterberg, f.p., bleeker, w., cooper r.a., davydov, v., gibbard, p., hinnov, l., house m.r., lourens, l., luterbacher, h-p., mcarthur, j., melchin, m.j., robb, l.j., shergold, j., villeneuve, m., wardlaw, b.r., ali, j., brinkhuis, h., hilgen, f.j., hooker, j., howarth, r.j., bakrač et al.: middle and late miocene palnological biozonation of the south-western part of central paratethys (croatia) geologia croatica 221 knoll, a.h., laskar, j., monechi, s., powell, j., plumb, k.a., raffi, i., röhl, u., sanfilippo, a., schmitz, b., shackleton, n.j., shields, g.a., strauss, h., van dam, j., veizer, j., van kolfschoten, th., & wilson, d. (2004): a geologic time scale 2004.– cambridge university press, 500 p. grill, r. (1943): über mikropaläontologische gliederungsmöglichkeiten im miozän des wiener becken.– mitteilungen der reichsanstalt für bodenforschung, 6, 33–44. haq, b.u., hardenbol, j. & vail, p.r. (1987): chronology of fl uctuating sea levels since the triassic (250 million years ago to present).– science, 235, 1156–1167. haq, b.u., hardenbol, j. & vail, p.r. (1988): mesozoic and ceno zoic chronostratigraphy and cycles of sea level changes.– in: wil gus, c.k., hastings, b.s., kendall, c.g.st.c., posa mentier, h.w., ross, c.a. & van wagoner, j.c. (eds.): sea-level changes – an integrated approach. semp special publications, 42, 71–108. hardenbol, j., thierry, j., farley, m.b., jacquin, t., de graciansky, p.c. &vail, p.r. (1998): mesozoic and cenozoic sequence chronostratigraphic framework of europeau basins.– in: graciansky, p.c. de, hardenbol, j., jacquin, t. & vail, p.r. (eds): mesozoic and cenozoic sequence stratigraphy of european basins. sepm spec. publ., 60, 3–13. harzhauser, m. & piller, w.e. (2007): benchmark data of a changing sea – palaeogeography, palaeobiogeography and events in the central paratethys during the miocene.– palaeogeogr. palaeocl, 253, 8–31. doi:10.1016/j.palaeo.2007.03.031 hochuli, p.a. (1978): palynologische untersuchungen im oligozän und untermiozän der zentralen und westlichen paratethys.– beiträge zur paläontologie von österreich, 4, 1–132. hudáčková, n., holcová., k., zlinská., a., kováč, m. & nagymarosy, a. (2000): peleoecology and eustasy: miocene 3rd order cycles of relative sea-leval changes in the western carpathian.– north slovak geol. mag., 6, 95–100. jaramillo, c.a. & oboh-ikuenobe, f.e. (1999): sequence stratigraphic interpretations from palynofacies, dinocyst and lithological data of upper eocene–lower oligocene strata in southern mississippi and alabama, u.s. gulf coast.– palaeogeogr. palaeocl., 145/4, 259–302. jiménez-moreno, g., head, m.j. & harzhauser, m. (2006): early and middle miocene dinofl agellate cyst stratigraphy of the central paratethys, central europe.– j. micropalaeontol., 25, 113–139. jiménez-moreno. g., rodríguez-tovar, f.j., pardo-igú zquiza, e., fauquette, s., suc, j.-p. & müller, p. (2005): high-resolution palynological analysis in late early–middle miocene core from the pannonian basin, hungary: climatic changes, astronomical forcing and eustatic fl uctuations in the central paratethys.– palaeogeogr. palaeocl., 216, 73– 97. juhász, g. (1994): sedimentological and stratigraphical evidences of water-level fl uctuations in the pannonian lake.– földtani közlöny, 123, 379–398. kollányi, k. (2000): újabb adatok a magyarországi pannóniai korú nannoplankton elterjedéséhez [new data to the distribution of pannonian nannoplanktonic fl ora – in hungarian].– földt. közlöny, 130/3, 497–527. kouli, k., brinkhuis, h. & dale, b. (2001): spiniferites cruciformis: a freshwater dinofl agellate cyst.– rev. palaeobot. palynol., 133, 273– 286. kováč, m., andreyeva-grigorovich, a., baj rakta rević, z., brzobohatý, r., filipescu, s., fodor, l., harzhau ser, m., nagymarosy, a., oszczypko, n., pa velić, d., rögl, f., saftić, b., sliva, ľ. & studencka, b. (2007): badenian evolution of the central paratethys sea: paleogeography, climate and eustatic sea level changes.– geol. carpath., 58, 579–606. kováč m., baráth, i., harzhauser, m., hlavatý, i. & hudá čková n. (2004): miocene depositional systems and sequ ence stratigraphy of the vienna basin.– cour. forsch. inst. senckenberg, 246, 187–212. lentin, j.k. & williams, g.l. (1998): fossil dinofl agellates: index to genera and species, 1998 edition.– aasp, contribution series, 34, 817 p. lewis, j., ellegaard, m., hallett, r., harding, i. & rochon, a. (2003): environmental control of cyst morphology in gonyaulacoid dinofl agellates.– in: matsuoka, k., yoshida, m., iwataki, m. (eds.): dino7, 7th international conference on modern and fossil dinofl agellates, abstract volume. additional abstract. lewis, j., rochon, a. & harding, i. (1999): preliminary observations of cyst-theca relationships in spiniferites ramosus and spini ferites membranaceus (dinophyceae).– grana, 38, 113–124. lučić, d., saftić, b., krizmanić, k., prelogović, e., britvić, v., mesić, i. & tadej, j. (2001): the neogene evolution and hydrocarbon potential of the pannonian basin in croatia.– mar. petrol. geol., 18, 133–147. magyar, i., geary, d.h. & müller, p. (1999a): paleogeographic evolution of the late miocene lake pannon in central europe.– palaeogeogr. palaeocl., 147, 151–167. magyar, i., geary, d., sütő-szentai, m., lantos, m. & müller, p. (1999b): integrated bio-, magneto and chronostratigraphic correlations of the late miocene lake pannon deposits.– acta geologica hungarica, 42/1, 5–31. marret, f. & zonneveld, k.a.f. (2003): atlas of modern organic-walled dinofl agellate cyst distribution.– rev. palaeobot. palynol., 125/1–2, 1–200. doi:10.1016/s0034-6667(02)00229-4 martini, e. (1971): standard tertiary and quaternary calcareous nanno plankton zonation.– in farinacci, a. (ed.): proc. 2nd int. conf. planktonic microfossils roma: rome (ed. tecnosci.), 2, 739–785. matthiessen, j. & brenner, w. (1996): chlorococcalalgen und dinofl agellaten-zysten in rezenten sedimenten des greifswalder boddens (südliche ostsee).– senckenbergiana maritima, 27, 33–48. mudie, p.j., rochon, a., aksu, a.e. & gillespie, h. (2002): dinofl agellate cysts, freshwater algae and fungal spores as salinity indicators in late quaternary cores from marmara and black seas.– mar. geol., 190, 203– 231. müller, p., geary, d.h. & magyar, i. (1999): the endemic molluscs of the late miocene lake pannon: their origin, evolution, and family level ta xonomy.– lethaia, 32, 47–60. nehring, s. (1994): spatial distribution of dinofl agellate resting cysts in recent sediments of kiel bight, germany (baltic sea).– ophelia, 39/2, 137–158. papp, a. (1951): das pannon des wiener beckens.– mitteilungen der geologischen gesellschaft in wien, 39–41 (1946–1948), 99–193. pavelić, d., kovačić, m., miknić, m., avanić, r., vrsaljko, d., bakrač, k., tišljar, j., galović, i. & bortek, ž. (2003): the evolution of the miocene environments in the slavonian mts. area (northern croatia).– in: vlahović, i. & ti šljar, j. (eds.): evolution of depositional environments from the palaeozoic to the quaternary in the karst dinarides and the pannonian basin. 22nd ias meeting of sedimentology, opatija – september 17–19, 2003, field trip guidebook, 173–181, zagreb. piller,w.e. & harzhauser, m. (2005). the myth of the brackish sarmatian sea.– terra nova, 17, 450–455. piller, w., harzhauser, m. & mandic, o. (2007): miocene central paratethys stratigraphy – current status and future directions.– stratigraphy, 4, 151–168. popescu, s.-m., dalesme, f., jouannic, g., escarguel, g., head, m.j., melinte-dobrinescu, m.c., sütő-szentai, geologia croatica 65/2geologia croatica 222 m., bakrač, k., clauzon, g. & suc, j.-p. (2009): galeacysta etrusca, dinofl agellate cyst marker of paratethyan infl uxes into the mediterranean sea before and after the peak of the messinian salinity crisis.– palynology, 33/2, 105–134. popov, s.v., shcherba, i.g., ilyina, l.b., nevesskaya, l.a., paramonova, n.p., khondkarian, s. o. & magyar, i. (2006): late miocene to pliocene palaeogeography of the paratethys and its relation to the mediterranean.– palaeogeogr. palaeocl., 238, 91–106. powell, a.j. (1986a): latest paleogene and earliest neogene dinofl agellate cysts from the lemme section, northwest italy.– in: wrenn, j.h., duffield, s.l. & stein, j.a. (eds.): papers from the first symposium on neogene dinofl agellate cyst biostratigraphy. american association of stratigraphic palynologists, contributions series, 17, 83–104. powell, a.j. (1986b): a dinofl agellate cyst biozonation for the late ologocene to middle miocene succession of the langhe region, nor thwest italy.– in: wrenn, j.h., duffield, s.l. & stein, j.a. (eds.): papers from the first symposium on neogene dinofl agellate cyst biostratigraphy. american association of stratigraphic palynologists, contributions series, 17, 105–128. powell, a.j. (1986c): the stratigraphic distribution of late miocene dinofl agellate cysts from the castellanian superstage stratotype, northwest italy.– american association of stratigraphic palynologists, contributions series, 17, 129–149. pross, j. (2001): paleo-oxygenation in tertiary epeiric seas: evidence from dinofl agellate cysts.– palaeogeogr. palaeocl., 166, 369–381. rögl, f. (1996): stratigraphic correlation of the paratethys oligocene and miocene.– mitt. gesell. geol. bergbaustud. österr., 41, 65–73. rögl, f. (1998): paleogeographic considerations for mediterranean and paratethys seaways (oligocene to miocene).– ann. naturhist. mus. wien, 99a, 279–310. rögl, f., spezzaferri, s. & ćorić, s. (2002): micropalaeontology and biostratigraphy of the karpatian-badenian transition (early -middle miocene boundary) in austria (central paratethys).– courier forsch. inst. senckenberg, 237, 47–67. rögl, f., ćorić, s., hohenegger, j., pervesler, p., roetzel,r., scholger, r., spezzaferri, s. & stingl, k. (2007): cyclostratigraphy and transgressions at the early/middle miocene (karpatian/badenian) boundary in the austrian neogene basins (central paratethys).– scripta fac. sci. natur. univ. masarykianae brunensis, ser. geology, 36, 7–13. sacchi, m. & horváth, f. (2002): towards a new time scale for the upper miocene continental series of the pannonian basin (central paratethys).– egu stephan mueller special publication series, 3, 79–94. soliman, a. & piller, w.e (2007): dinofl agellate cysts at the karpatian/badenian boundary of wagna (styrian basin, austria).– jahrbuch der geologischen bundesanstalt-a 47, 405–415. stover, l.e., brinkhuis, h., damassa, s.p., de verteuil, l., helby, r.j., monteil, e., partridge, a., powell, a.j., riding, j.b., smelror, m. & williams, g.l. (1996): mesozoic–tertiary dinofl agellates, acritarchs and prasinophytes.– in: jansonius, j. & mcgregor, d.c. (eds.): palynology: principles and applications. american association of stratigraphic palynologists foundation, dallas, 641–750. sütő-szentai, m. (1985): die verbreitung organischer mikroplankton-vergesellschaftungen in dem pannonischen schichten ungarns.– in: papp, a., jambor, a. & steininger, f.f. (eds.): pannonien (slavonien und serbien) chronostratigraphie und neostratotypen, miozän der zentralen paratethys.– akadémiai kiadó, budapest, 517–533. sütő-szentai, m. (1988): microplankton zones of organic skeleton in the pannonian s.l. stratum complex and in the upper part of the sarmatian strata.– acta. bot. hung., 34/3–4, 339–356. sütő-szentai, m. (1989): mikroplanktonfl ora der pontischen (oberpannonischen) bildungen ungarns.– in: stevanović, p., nevesskaya, l., marinescu, f., sokač, a. & jámbor, á. (eds.): chronostratigraphie und neostratotypen: neogen der westlichen (“zentrale”) paratethys. bd. viii: pontien. jazu and sanu, zagreb–belgrade, 842–869. sütő-szentai, m. (1991): szervezvázú mikroplankton zónák magyarország pannoniai rétegösszletében. üjabb adatok a zónációról és a dinofl agellaták evolúciójáról (abstract: organic – walled microplancton zones of the pannonian in hungary. new data on the zonation and dinofl agellate evolution).– őslénytani viták discussiones palaeontologicae, 36–37, 157–200. sütó-szentai, m. (1994): microplankton associations of organic skeleton in the surroundings of villány mts.– földtani közlöny, 124/4, 451–478. sütő-szentai, m. (2005): mikroszkóppal az ősi élet nyomában (tracing ancient life with a microscope).– in: fazekas i. (ed.): a komlói térség természeti és kultúrtörténeti öröksége (natural and cultural heritage of komlo district), regiografo bt., komlo, 39–56. sütő-szentai, m. (2011): az egerág-7. és bosta-1. számú fúrások pannóniai dinofl agellata együttesei (dél-dunántúl) pannonian dinofl agellate associations from boreholes egerág no. 7 and bosta no. 1 (southern hungary).– e-acta naturalia pannonica, 2/1, 111–133. šikić, k., basch, o. & šimunić, a. (1979): osnovna geološka karta sfrj 1:100.000. tumač za list zagreb l33-80 [basic geological map of sfrj 1:100.000. geology of the zagreb sheet − in croatian].– institut za geološka istraživanja zagreb (1972), savezni geološki zavod, beograd. tappan, h. (1980): the paleobiology of plant protists. freeman, 1028 p. tyson, r.v. (1987): the genesis and palynofacies characteristics of marine petroleum source rocks.– in: brooks, j. & fleet, a.j. (eds): 1987. marine petroleum source rocks. geol. soc. spl. publ., 26, 47–67. tyson, r.v. (1995): sedimentary organic matter. organic facies and palynofacies.– chapman and hall, london, 615 p. vasiliev, i., bakrač, k., kovačić, m., abdul aziz, h. & krijgsman, w. (2007): paleomagnetic results from the sarmatian/ pannonian boundary in north-eastern croatia (vranović section; našice quarry.– geol. croat., 60/2, 151–163. vrsaljko, d. (1999): the pannonian palaeoecology and biostratigraphy of mollusca from kostanjek-medvednica mt., croatia.– geol. croat., 52/1, 9–27. vrsaljko, d., pavelić, d. & bajraktarević, z. (2005): stratigraphy and palaeogeography of miocene deposits from the marginal area of žumberak mt.and samoborsko gorje mts. (north western croatia).– geol. croat., 58/2, 133–150. wall, d., dale, b. & harada, k. (1973): descriptions of new fossil dinofl agellates from the late quaternary of the black sea.– micropaleontology, 19, 18–31. wall, d., dale, b., lohmann, g.p. & smith, w.k. (1977): the environmental and climatic distribution of dinofl agellate cysts in modern marine sediments from regions in the north and south atlantic oceans and adjacent seas.– mar. micropaleontol., 2, 121–200. zevenboom, d. (1995): dinofl agellate cysts from the mediterranean late oligocene and miocene. ph.d. thesis, university of utrecht, cip-gegevens koninklijke bibliotheek, den haag, the netherlands, 221 p. manuscript received november 14, 2011 revised manuscript accepted april 25, 2012 available online june 29, 2012 geol. croat. 50/2 1161 -162 1 zagreb 1997 professor herak's contribution to karst geology and hydrogeology stjepan bahun' and bozidar mondie' the principal croatian newspaper, the zagrebian " vjesnik" carried the following heading on 23 march 1972: "our scient ist on the top of the global list of karst researchers", it was a short review of a new book edited by herak & stringfield ent itl ed "karst important karst regions of the northern hemisphere". at that tim e, to gather together authors from thirteen "karst" collntries each having different concepts and views on the karst, including the usa ancl ussr, was not only a scientific feat but also a tremendolls organizational acl. thi s bulky and enduring project was given to herak who, after hi s long term effective and globally recog­ nised karst research, became an outstanding connois­ seur of karst geology. therefore, we think that it is a most outslanding acknowledgement to our karst rese~ archer. but a ll this, as usua l, started much earlier, when herak became a member of the geological museum in zagreb. under the directorship of josip poljak, a co n­ noi sseur, and in tha t time the only serious karst resear­ cher in croatia. with him , herak had already in 1946 performed hydrogeological exploration in gorski kotar (he vinodol) and in 1947 around the cetina river (the peruca reservoir). later, working in the area of the zagorska mreznica river, poljak, after herak 's argu­ mented influence, accepted the innundation of a karst sprin g, which facilitated the later construction of the sablj ac i reservoir ncar ogu lin. there, as herak says, he realised fo r the first time that the karst hydrogeology may be understood only if th e geo logica l structure of the terrain studied is well known. such an approach cons ists of, first of all, a scientifical!y proved geologi­ cal basis that explain s the hydrogeological conse­ quences. herak was convinced and tri ed to prove through many examples that the karst hydrogeo logy cannot bc understood without a thorough knowledgc of geological structure clements of the terrains studied, as the later hydrogeological practice confirmed it. endea­ vours to formulate a general karst theory, as shown by davis (1930). grund (1903), katzer (1909). cvijic ( 191 8) and rogjic (1972). became progressively more invalid as field invest igations became ever more deci~ i department of geology and palaeolllojogy, facu lty of sc ience, university or zagreb. uj. kra lja zvonimira 8, hr-ioooo zagreb, croat ia. 2 institute of geology, sachsova 2, p.o. box 268, hr -10000 zagreb, croatia. sive. therefore, herak's works in 1956 and 1957 on the geological problems of the mala kapela mt. and on the gcological basis of certain hydrogeological phenornena in the dinaric karst, arc considcred as a land-mark between the descriptive and sc ientifi c approaches to karst research. the application of hi s favourite saying "a peasant and water are not st upid; they always find the easiest ways" can be found in each of his works because water will flow only through the underground where the geological structure permits ~ but this struc­ ture has to be correctly understood. this "but" was most frequently a stu mbling block and a basic misunder­ standing bel ween the geologists and the "consumers" of geology, and less commonly between pure geologists themse lves. herak insisted in the resolution of these misundcrstandings by stubbornly and patiently drawing fundamental geology and its practical application s together. he also in troduced such an approach toward practi­ cal problems into his new lectures on hyd rogcology and engineering geology, that he opened within the techni­ cal faculty in zagreb, where he came from the geologi­ cal museum in 1952. his continuous collaboration with the hydro-power engineers convinced him that such a practical approach is correct and gave him numerous wonderful examples needed for the educat ion of stu­ dents. the permanent impact of practical phenomena on fundamental investi gat ions and vice versa stimulaled him to introduce such an approach into his lectures. by that, he transformed the old term "the applied geology", that encompasses some segments of geol ogy into "the application of geology", by which the entire geology with all its cognitions can serve for various practical uses. as a result, there is a saying about "the zagrebian school or karst hydrogeology". on the basis of all th is, he introduced the lecture "ka rst geology" within th e faculty study and "selected chapters from karst geolo­ gy" within postgraduation study. his mu ltip le, complex field inves ti gations in lat e 1950's included hvar island, the reservoir on the gra­ cacko polje (obrovac hydro power plant) , the upper kupa river basin (where a considerable allochthony of this paper 'yas presented at the scientific meeting dedicated to the 80th anniversary of the life of professor milan herak, held on march 5th, 1997 in zagreb 162 pa laeozoic deposits wefe discovered) , the national park pi it vice lakes, the lika and gacka rivers (senj hydro­ power plant), the busko blato, the trebi snjiea hydro­ power plant and a series of hydrogeological studies and reviews with in the area of the former yugoslavia (jam­ nicka kiselica. drilla river, tara-moraca rive r system clc.). the experience gathered within slich a large area convi nced herak that his opinion on the importance of tectonic elements in the ex planation of ka rst pheno­ mena was valid. tn 1965 elsevier publi shers reques ted that herak write a book based on hi s karst exploration experiences, and this appeared. the book was published in 1972 as a significant contribution to the science of karst hydroge­ ology on the global level. after this event , herak beca­ me a world known expe rt on karst hydrogeology which resulted in hi s invitation to the most prest igious meet­ ings and help the resolu tion of the most complex hydro­ geological technical problems. in 1959 herak visited the kharga oasis in western egypt where deep wells were drilled in order to extract groundwater. a rter this, he went to iran firs tly to rev i­ ew the geology o[ the mashabad area, where a hydro­ power dam was to be constructed, and later as a consul ­ tant or the irranian government which allowed acccss to the research centers within the iranian karst region. herak's reg ional geolog ical knowledge was utiliscd in the resolution or walei' problems at the nabatich reser­ voir in lebanon and followed by other reservoir pro­ jects in lebanon, as [or example reservoir in the litany river valey. these links with lebanon laler resulted in a lebanese student obtaining a phd [rom the university of zagreb. in turkey, herak exp lored the taurus mountain area, which together with the reeva luat ion of the geology of the manavgat river valley resulted in the const ruction of a big reservoirs. in 1967, herak vis ited jamaica as an expert of the un ited nat ions (fao) for two months where he he lped to determine the catchment areas of major coasta l karst springs. afte r resolvi ng the basic geological structure or the island, the catchment area was discovered to be ten times larger than prev iously thou ght. this resulted in herak 's e lection as the un fao chaimlan of a group in c harge or g rou nd water in fi ssured rocks. in 1969 aftcr rcncwal o f this post, as a president or the expcrt group, he visited mediterranean countries to check the ac ti vity of un dcvelopment programmes related to the usc of kars t groundw ater. he also co llec ted the local karst te rms in usc in turkey, greece, tunis, alger, spain and whi ch toge the r wit h those from germany, france, england, ital y and croatia were publi shed in a multilingual dictionary in 1972 by the un and unesco. in 1980 herak undertook hi s final task for the un when he he lped in the exploration for karst g roundwater in the molai reg ion of the pe loponnese. there, he proved irrefutably the decisive role played by overthrust tec toni cs in the occurencc and !low o[ grou ndwater. geologia croatic;i 50{2 personal experience, scientific interpretations and research approaches to the karst exploration herak pre­ sented on numerous intcrnational conferences on kars t hydrogeology, as dubrovnik, moscow, canary islands, montreal, etc. between 1956 and 1986 he published 39 scientific papers related to the karst. from the first pub­ lis hed paper in 1956 "0 hidrogeoloskim probl emima male kapele" (on hyd rogeo logical problems of the mala kapela mt.) till that one published in 1986 "geo­ tektonski okvir zaravni u krsu" (geotectonic framework of karst plateaux) which, we do believe, will not be hi s last pape r on the karst. during this time period herak developed . complemented and refined hi s initial con­ cept. as time passed he became progressive ly more inte res ted in geotectonics and his work on the karst consisted ever more of intcrpretation based on his broad knowledge and unde rstanding of regional geology and geotectonics. his opinion on the hydrogeological fun c­ tion or karst terrains and on the spacial conditions in the occurrence of karst aquifers achieved a final form in the "osnova hidrogeoloske karte dinarskog krsa" (the ba­ sis of the hydrogeologica l map of the dinari c karst). scale 1:500,000, that was prepared by him and his col­ laborators in 1974. this map later became the basis fo r the hydrogeological map at the same scale of the fo rmer yugoslavia. the paper published in 1977 entitled "tecto-genetic approach to the classification of karst terrains" (tekto­ genet ski pristup klas ifikaeiji krskih terena) represented the condensation o[ all herak 's knowledge. he rema­ ined consis tent to himself and set geological conditions as the basis for unde rstanding the origin o[ the kars l med ium and all tectonic changes to which the kars t ter­ rains were exposed. these lwo explicitly "geological" eleme nts can always be reco nstruc ted in regional fra­ meworks and by means of' available geologica l i11 cth · ods. !-lis di vision of karst terrains into the epi -orogenic karst ([ormed in tectonically stabilized terrai ns without late r signi ficant tectonic deformat ions) and orogen ic karst (formed in tectonica lly mobile terrains wi th late r conside rablc tectonic deformation s), will remain des­ pite poss ible changes re lated to the geotectonics and variations in terminology, because it was based on the 1110s1 e lementa ry and unchanged geologica l th ought. the di visions within these two main karst types (tabu ­ lar, homoclinal, folded, basin-type and deep ones in the epi-orogenic karst, and lenticular, folded, dissected and accumulated ones in the o roge ni c karst) call be partly modified , but they will remain recognizable fo r the ir basic charac teristics and applicable in the c1assi fi cati on of karst tcrrains. in this way, herak marked the path for future scicn­ tists to follow. he significantly changed the approach to karst exploration, surpassing his predecessors and beco­ ming the central fi gure among the karst explore rs or this century. herak deserves our si nce re gratitude for everything that he achieved in this field of science. geol. croat. 50/2 20 1 2 14 i fig. 3 tabs. 2 pis. zag reb 1997 upper triassic biostratigraphy and algae from zumberak (croatia) tonci grgasovic key wo r ds: biostratigraphy, foraminifera, dasy­ c ladalcs, upper triass ic, croalia. abstract in the upper triassic do lomi te deposits o f the zu mbcrak region (west o f zagreb, croatia) the followi ng local biostratigraphic zones arc di stinguished: clypeillo hesici taxon-range zone (carnian). alllv­ lo,.f/ts .~iilifu.flfs interval-zone (norian), and triasijl(l /uliirkclli taxon­ range zone (rhaet ian). dasycladal a lgae c/)'/jeinll besici pantic, griphupurd/a c/t/ta/(l (cum bel), physoporella jomdaellsis flu· g el & m u and acic/ffdla sp. are accurately described. 1. introduction the zumbcrak mountains lie to the west of zagreb, in the bo rder area with the republic of s lovenia (fig. i ). they arc predominantly composed of triassic dolo­ mites, but pcrmian to quaternary deposits a lso occur. ow ing to its prox imity to zagreb, zumberak has been the subject o r re latively numerous geologica l inve­ st iga tion s. the firs t extensive work that included the stratigraphy o f triassic deposi ts of th is region was wril­ ten by gorj anovic-kramberger ( 1894). shon stratigraph ic desc riptions of particular loca lities were give n by herak et a l. ( 1965) and herak (1968). herak ( 1957) reponed on the find o f the alga sphae­ rocodiuli/ bornemanni on me sv. gera in z umberak whi le babic ( 1970) es tablished that this was not a fos­ sil taxon but rather an onco idal sedimentological struc­ ture. work ing on the basic geo logica l map (scale i: 100.000), sheet novo mesto, plenicar & prem­ ru ( 1977) distinguished the middle and upper triassic dolomites altogethe r, in which the o nl y " foss ils" a re splwerocodilll1l. o n the zagreb sheet, sikh: e l a!. (1979) clisti nguished the middle and upper triassic and reported the occurrence of a "several metre th ick zone with interlayers or dark grey to black sha les", ror which they assumed a carnian age, wi th in the lower part of a thi ck s llccess ion of upper triassic dolomites . in the upper part of the dolomite deposits they recorded the lnsli wi c of geo[ogy, sachsova 2, p.o. box 268, hr[0000 zagreb, croa tia. kljucne rijeci : biostratigrafija, foraminifere, dasy­ c ladales, gornji trijas, f-irva tska. sazetak u podrucj u zum berka (zapadno od zagreba, hrvatska) ii dolomi tn im nas tagmna gonjeg irijasa izdvojene su sljedece lokal nc biostmtigrafske zone: rasponska zona ci)1jeilla he.\·;ci (karnik), inter­ val-zona ai/joror/li.'> sill/l0.'>/1s (norik) i raspo nska zona tr;a.~il/(l iuii/ ­ ikel/; (ret). detaljnije su opisane dazi kt adal nc atgc ci)1u: il/(i besici pantic, griplwporella cl/iwija (gumbel), physupordja )uiii­ d(/ellsis flugel & mu i acicli/ella sp. a lte rna tion of dolomites, dolom it ized lim estones and lim estones . problemati c algae in c lud ing thawnato ­ porella parvovesicultjera, aeolisacci/s dutlningtolli and aeo/isaccus sp. , and the foraminifera involwina sp. and glomospira sp. are the only mentioned foss ils. in the immediate vici nity, in the samobor moun­ tains, triass ic deposits have been investiga ted by her­ ak (1956) and babic et al. ( 1980). gusic & babic (1972) and gusic (1975) wro te about the upper trias­ sic and liassic microfossils of the adjacent medved ni­ ca, and fucek e t al. (1995), korolija e t al. ( 1995), prtoljan et al. (1995) and sokac & grgasovic ( 1995) about the upper triass ic sediments and fossils o f medvednica. simunic & s im un ic ( 1997) deals with the triassic depos its of hrvat sko zago rje, and bukov ac & sokac ( 1989) wro te about the upper triassic and liassic of the adjacent reg ion o r gorjanci (s loveni a) . as part of recenl inves tiga tion s for the geological map of the republic of croati a (scale 1:50.000) dc ta­ iled lithost rat igraphic columns were measured through triassic deposits on well exposed outc rops in the slap­ nica creek, nw of krasic. based on the resea rch results, a lithostratigraphic subdi vision was made of the triassic deposi ts into several forma tions and members (buko­ vac et ai. , 1995; grgasovic, 1995). the fo llowing uni ts were separated wi thin the upper tri assic (fig. i): the slapn ica fonnation is composed o f early diagene tic this paper ,vas presented at the scientific meeting dedicated to the 80th an niversary 01" the lil"e 01" professor milan h erak, held on march sth, 1997 in zagreb 202 geologia croalica 50/2 chronojsio-i_ lithostratigraphic lithology fossils units ij~s~~ ~\t( rajici ~"~ slo r.j ... ·· .... ·· ... 1 . ..... j ~ '" 0 '" / / / " " " t f samobor ~ ~ t'~ ~ .. z z ;;; c:: c :'!: "' ~ / / / f"" w "' -:::l ..: i ·s / u a: '" .~ ~ ~ 1---300m ~t -.:::r .... w ::e .... -r--~ en '" -:::. co '" ::e 0 -' ~i :::. co ~/~ 0 ·s co -' en '" <:> z co ..: <:> /:~ --a: '" -« 0 ~ z z .9 > z -~::-~ _-:~i. .2 "" -:::. " "" -' -=-1-=-'" ::e -~ -~ :~ a: ~ • • ~ • u § • 0 :q .. " e > ~ f'" jj ~ z '" "" 0 ..: -0 <..j 0 z ~ z "' c.. f ~ a: s "" ..: '" -' ~ u ~ '" / -.--l • () i~~~~ ruskovwe / / dolomites, represented by more or less regular rhythms of doiomicrites, fenestral dolomicritcs and dolomitic stromatolites. beds arc clearly distinguished and about 20-65 em thick. these sediments were deposited in a peritidal environment showing a sha llowing-upward tendency. two members were separated within the slapniea formation. within the rhythmic dolomites of the lower vranjak member, milimetre to centimetre­ thick yellow-green shales are intercalated. in the upper part the dolomites of drcnovac member (which have a high organic mattcr content) arc very dark coloured. very thin coal interlayers also occur as a result of the formation of anoxic lagoons. the upper part of the dolomitic succession is designated as the main dolomite formation, which is characterized by the gen­ crally irregular lateral and vertical alternation of three main structural types of early diagenetic dolomites: dolomicrites, fenestral dolomicrites and dolomitic stro­ matolites with very fine undulating laminations. thcsc stromatolites mostly belong to the type of so-called ~ , ~ 0 e ~ 0 0 ~ • e • ~ • ~ .• ~ ;g 0 0 li 0 .~ • ~ ~ ~ 2 ~ ~ 2 0 .. ~ ~ ~ j i i i i i i i i i 6 t:? o jasliebarsko ~* 0 i • ? • • ~ .~ • • i • ~ • 0 .. ~ 0 0 0 " i ~ l" 0 ti ~ 0 i '@ 0 • 0 ~ .. • 0 " 0 0 i • ." ~ ~ 1': ~ ~ 0 ~ " .[ ~ ~ 0 0 ~ ~ 0 q ~ • 0 e 0 ~ " :l~ "~ 2 ~ i ~ i i i i l t2i] • 263] 3~ 46 s§l 6[3 7~ fig. i schematic stratigraphic column or the upper trias­ sic deposits or zumberak, with the geographical loca­ tion or investigated outcrops in the slapnica creek. leg­ end : i) limestone: 2) dolo­ mite; 3) dolomite intraror­ mational breccia; 4) dolomi­ erilc rich in organic mallei'; 5) shale; 6) fenestral fabric; 7) stromatolite. skeletal stromatolites whereas thosc or other units arc of ihe agglutinated type (sensu riding, 1991). the real bedding planes arc difficult to observe, while stylo­ lites are clearly expressed. these deposits were formcd in the peritidal tidal flat environments on a stable car­ bonatc platform. two members were separated in the upper part of this formation. the kalje mcmber is com­ posed of intraformational breccias with dolomicritic cement and fragmcnts of the described dolomite types. bukovac et a!. (1995) and grgasovic (1995) re­ fer to this member as the gmajna breccias but, since this name is used in a number of localities, the name kalje aftcr the near-by village has been adopted. the younger, posinak member, is characterized by generally well stratified dolomicritcs, and the rare occurrence of dolomitic limestones and limestones. fenestral dolomi­ crites are less frequent and dolomitic stromatolites arc mainly horizontally laminated and contain lcss numer­ ous fenestrae. the sedimentary environment may be defined as peritidal with the prevalence of subtidal congrg;nlvic: upper t riassic 13iostll1igr;lphy and /\ igae from zumberak (croatia) ditions. there is a cont inuous transition into liassic limestones. while detailed columns were recorded, a rich fossil content was found in several fossiliferous interlayers, which made it poss ible to define the age of discfetc lithostratigraphic units and observe the fossi ls within fossil assemblages. these results as well as the obser­ ved differences in the fossil content at particular levels instigated the definition of a local biostratigraphic zona­ tion for these upper triassic deposi ts, with a more extensive survey of dasyclad algae. 2. biostratigraphic zones 2.1. clypeilla besici taxon-range zone boundaries: boundaries arc defined by the occur­ rence and disappearance of the index species. fossil content: besides frequent fragments and scarce whole skeletons of the dasyclad alga c/ypeina besici pantic (pi. ii. figs. 2. 4-7,11-12,16-19), there arc numerous foraminifera including lamellicolllls pro­ eel'iis (uebus) (pi. 1, fig. 17), lalllellicollus mu/li­ spi/'lls (oberhauser) (pi. i, figs. 15-16) and aulo­ iol'lus/i'ied/i (kristan-tollmann), and less fre­ quently aii!otor{us sinlioslis weynschenk (pi. i, fig. 9; pi. ti, fig. 5 pars) and all/otortus cf. relluis (kristan) . the problematical dasyclad alga acicu/el­ la sp. was also round (pi. 11, fig. 9). stratigraphic range: camian. correlation: sinec c!ypeilla besiei pan tic has a conrirmed carnian range (sec section 3), this zone may be correlated with other cocval foraminiferal zones, e.g. (he poroophra/lllieliwli corpafiliclil1i range-zone (sal­ aj el ai. , 19883, b) or the pi/ofj1l11inella kuthal1i inter­ val-zone (sa laj et ai., 1983). the carnian age of th is zone is also confirmed by palynological data (jerinic in bukovac et ai., 1995) . this stratig raphic zone fully coincides wi th the extension or the slapnica lithostratigraphic unit. this coincidence may be the result of extension of the envi­ ronment favourable for the survival of c. besici, as dasyclad algae show a pronounced environmental depenclence (e.g. berger & kaever, 1992). 2.2. aii/olorlus sillllosiis interv al zone boundaries: the lower boundary of this interval­ zone is defined by the disappearance of c/ypeina besici pantic, and the uppcr boundary by the appearance of tri{hilla liallfkelli majzon. fossil content: some foraminifera continue iillo this zone, including: au/oforfus fl·ieelli (kristan­ tollmann) (pi. ii , fi g. i pars) , au/olorills lellllis (krist an) and the index species auloforllls sinllosus weynschenk (pi. ii, fig. 1 pars), which is thc most 203 numerous. therc are also occurences of: alf/otor/lls ilimidlis (kristan-tollmann), trochammilla sp ., the coprolile ?parajavreina flioronetellsis bronni­ mann et al. (pi. i, fig. 19) and the dasyclad alga physopore//a jomdaellsis flugel & mu (pi. ii, figs. lo,14-15). stratigraphic range: since the assemblage has a rather wide stratigraphic range, this zone is defined as an interval zone. the age is probably norian. correlation: duc to insufficient material, no corre­ lation can be made with other known biostratigraphic units. this biozone with its range may be generally identi ­ fied with the lower part of the main dolom ite forma­ tion, below the kalje breccia member. due to the small number of palaeontological data, the boundary with the overlying tri{lsina halltkeni zone is only approximate. 2.3. triasilla hallikelli taxon-range zone boundaries: boundaries afe defined by the occur­ rence and disappearance of thc index species. fossil content: together with nurnerous triasil/o hallikelli majzon (pi. j, figs. 1-3; pi. ii, fig. 3 pars), other foramin ifera including: au/oeof/us penlloelis­ co ides (oberhauser) (pi. i, figs. 12, 18) and aii/o­ lorills sillllosils weynschenk (pi. i, figs. 8, 10?, ii pars) also occur, and less freq uently au/otortusjriedli (kristan-tollmann) (pi. 1, figs. 4-5, 7; pi. ii, fig. 3 pars), aii/oioriils lenllis (krist an) (pi. 1, fig. 6) and trochammilla sp. (pi. i, fig. 11 pars), as well as the dasyclad alga griphoporella cllrvala (gumbel) (pi. ii, figs. 8 , 13). the association also contains numerou s fragments and skeletons of a gymnocodi­ acean alga (pi. ii , fig. 3 pars), previously unknown and described in sokac & grgasovic (1998 1il press). stratigraphic range: the stratigraphic range of thi s zone is determined by the range of thc index species . most authors maintain the range is upper noriall­ rhaetian (e.g. zaninetti, 1976; piller, 1978; salaj et ai., 1983; ora vecz-scheffer, 1987), while others think it is only rhaetian (e.g. ciarapica et ai., 1987; sartorjo & venturini, 1988; de castro, 1990; rohl et a!., 1991). correlation: the triasina hallfkeni range zone has been repeatedly determincd in the tethyan region (e.g. ciarapica ot a!. , 1987; salaj et ai., 1988a, b; v achard & fontaine. 1988; v aci-iard et a!., 1990; rohl et a!., 199 l) and may be well correlated with the zone separated in the zumberak region. this fossil assemblage is fo und in the beds immedi­ ately underlying the kalje breccia and in fragments within breccias, so the triosilla halltkcni bio-zone seems to include part of the upper segment or the main dolomite formation, the kalje member and possibly the posinak member. gusic & babic (1970) have 204 found triasillo cf. hal1fkeni in limestones south of tisovec village, which probably belong to the posinak member. 3. palaeontology order dasycladales pascher 1931 family acetabulariaceae hauck 1885 t.-ibe clypeineae elliot 1968 genus clypeina (michelin 1845) bassoullet et al. 1978 clypeilla besici (pantle 1965) pantie ill granier & deloffre 1995 pi. ii. figs. 2, 4-7.11-12,16-19 selected synonymy (page numbers only if there is a description or a comment on the species): 1965 clypeinl1 bdici n.sp. pa ntie, p. 133-136 (137-141); pi. i, figs. 1-6; pi. ii, figs. 1-7; pi. ill, figs. 1-6; pi. iv, figs. 1-2; pi. v, figs. 1-3 1967 clypeii/a bdici pantle pantic, pi. vii, figs. 1-3 1967 clypeii//1 sp. holzer, p. 77-79; pi. 1, figs. 12, 8 pars 1968 ?clypeii//1 besici pantic durdanovic, pi. i , fig. 9 1972 dasyeladacca kodra. pi. 3. fig. 8 1972 clypeii//1 cf. besici pantic ott, p. 91-93; figs. 2.1-2.13 1972 clypeii/g bdici pantic pantic, pi. v, fig. 1 1972 clypeii//1 besici pantic pantic & ramp­ noux, pi. ii, fig. 4 1972 clypeii/11 bdici pantlc kemenci, pi. ill , figs. 7-8 canovic & 1974 clypeii//1 besici pantic bukovac, veltc & sokac. n.f. 1974 clypeii/a bdici pantic pantic, pi. v, figs. 1-2 1975 clypeii//1 bdid pantic pantic. pi. lxxi, figs. 1-2; pi. lxii, fig. i 1977? clypeii/a sp. flajs, p. 11; pi. 17, fig. 6 1980 clypein/1 besici pantic babic, gusic, krystyn & zupanic, n.f. j 980 clypein/1 besici pantic dragastan, fig. 103 1983? clypein/1 sp. schafer & senowbari­ dar y an, p. 119; pi. 6, fig. 6 1984 clypeina besici henrich, pi. 9, fig. 6.2; pi. is , fig. 1.2 geologia cronlica 50(2 1995 clypeina besici pantic pantic in gra­ nier & deloffre, p. 57 & 62, choosing the lectotype between syntypes: pi. i , fig. 1 in pan­ tlc (1965) the original description (pantic, 1965, p. 135) is translated from serbian: "the fossilized thallus of this alga is made up of fertile whorls, shaped like a wide rimmed glass. whorls are slightly overlapped. whorl branches are thinner in the proximal pan, gelting slightly thicker towards the distal part. there are between 12 and 22 branches. they arc fused along almost their entire length, except for a small free part at the distal end. each branch is connected with the axial cavity through a tiny pore, siluated ncar the whorl base. " discussion: holzer (1967) described as clypeilla sp. a form which is, except for its slightly larger dimen­ sions, identical with clypeina besici pantle in all of its characteristics. ott (1972) described somc nicely preserved specimens from austria, displaying a thallus shaped like a string of icc-cream cornets, and compared them with those described by holzer. schafer & senowbari-dar y an (1983) also compared their specimen with holzer ' s. the table of dimcnsions (table 1) shows that the specimens described in the present paper are generally smaller than those in the aforementioned works, but it also shows that the stud­ ied species manifests some variability in dimensions. as a taxonomic criterion, dimensions arc much less important than the elements of algal st ructure: the shape and distribution of branches, shape and ornamentation of the thalius, etc. (bassoullet et ai., 1977). there­ fore , specimens from zumberak, as well as those from other works cited in the synonymy, may be withoul reservation classified as belonging to clypeillo besici. studying the calcification processes in algae, flajs (1977) points to the upper triassic clypeilla sp. (poss i­ bly c/ypeilla besici) as an example of preserved prima­ ry structure with calcification of a similar type to that of the recent cymopolia. the zumberak specimens agree with the original description. branches are densely disposed within the whorls and the whorls are widely spaced along the thal ­ lus. because of their dense arrangement branches arc sometimes horizontally flattened (pi. ii, fig. 7). proxi­ mal branches ascend steeply and then, bending convex­ ely, abruptly expand (pi. ii, fig. 5) and finaliy taper to a point (pi. ii, figs . 12, l6). fomlation of gametes (unca­ lcified) seems to have taken place in these expanded branch parts (cladosporous type). the basal pore of ihe branch is rarely visible (pl ii, figs. 6, 17). each branch is fully covered by a thin regular calcareous envelope of an average thickness of 0.03 mm (pi. ii, figs. 5, 7, j.6, 18). the main ax is is covered by a less regular and slightly thicker envelope (ca. 0.05 mm; pi. ii , fig. 5). the internal thallus wall is entirely smooth (pi. ii, figs. 2, i 1, j 7-18). proximal parts of calcified branches arc grgasovic: upper triassic biostratigraphy and algae from zumberak (croat ia) 205 grgasovic pantic holzer (1967) on (1972) schafer & senowbari­ daryan dimensions in mm (1997) (1965) (1983) outer thallus diameter at the 0.44-1.06 (0.7) 0.896-1.84 1.25-2.68 0.95-1.7 (1.13) 2.8 whorl level (dmax) n = 14 n=7 outer thallus diameter 0.21 -0.55 (0.37) between whorls (dmin) n = 14 inner thallus diameter (d) 0.09-0.36 (0.21) 0.56-0.672 0.42-0.64 0.24-0.36 (0.31) 1.2 n = 15 n = 6 the did relation in % 19.1 -49.3 (31.5) 23.8-33.6 21.2-34.7 (28.2) 23 n = 14 n=6 distance between whorls (h) 0.47-0.51 (0.49) 0.56-0.672 1.07-1 .43 0.43-0.79 (0 .53) 2.8 n =3 n =5 the hid relation in % 69.9-82.8 (77.9) 20-50? 23-35? (29?) 44.3-52.7 (47.5) 100 n =3 (35?) n=5 diameter of pores (p) 0.05-0.10 (0.08) 0.06-0.128 0 .06-0.10(0.08) n = 12 n =6 number of branches 10-15 (13) 12-22 10-12 15 per whorl (w) n =8 table i dimens ions of clypeillg hesici pant le. the mean value is given in parentheses and "n" refers (0 (he number of measurements. dimen­ sions of specimens described by ott (1972) were determined from the illustralions. joined together, bui they separate towards the distal part, giving a flower-like appearance in cross section (pi. ii , fi gs . 2, 11-12, 18). due 10 il s characteri st ic shape, the thallus often disintegrates into discrete seg­ ments. an unusual section shown in pi. ii , fig. 19 may indicate the top pan of the thallus. the original skeleton minera logy was aragonite (flajs, 1977, p_ 74), which was replaced by mosaic dolomite crystals probably dur­ ing earl y diagenesis. stratigraphic range: most authors state a carnian age for ihi s al ga (pantic, 1965, 1967, 1972, 1974, 1975; durdanovic, 1968; ott, 1972; pantic & rampnoux , 1972; canovic & kemenci, 1972; dragastan, 1980). olhcrs state oecurences in ihe cordcvolian along with poikiloporella duplicata (pia), but fin din g only in wetterstein limestone may implies ihe racies dependance (holzer, 1967; ott, 1972; henrich, 1984). some uncertain finds were deter­ mined only as upper triassic (flajs, 1977; scha­ per & senowbari-daryan, 1983). the norian­ rhaetian age from kodra (1972) is uncertain. in this paper, the age of beds with clypeil1a besici pantic can also be defined as carnian. gcographical distribution: albania (kodra, 1972), aust ria (holzer, 1967; ott, 1972), bosnia and herzegovina (pantic, 1965), croalia (b uko­ v ac et ai., 1974; babic cl ai., 1980 and present pa­ per), germany (henrich, 1984), greece (schafer & senow bari-daryan, 1983), italy (flajs , 1977), romania (dragastan, 1980), slovenia (du­ rdanoyic, 1968) and yugoslavia: monlenegro (pa­ ntie , 1965 , 1975), serbia (pantie, 1967, 1972; pantic & rampnoux, 1972), yojvodina (cano­ vic & kemenci, 1972), and kosovo (pantlc, 1974). family t riploporellaceae (pia 1920) berger & kaever 1992 tribe salpingoporeljeae bassoullet et ai. 1979 subtribe salpingoporeljinae bassoullet ct ai. 1979 genus griphoporella (pia in spitz & dyhren­ furth 1915) bara ttolo et ai. 1993 griphoporella curvala (gumbel 1872) barat­ tolo ct al. 1993 pi. ii, figs_ 8,13 selected synonymy (page numbers only if there is a description or a comment on the species): 1872 gyroporel/a curva/a n. sp. gumbel, p. 280; pi. d.lv, fig. 2.a-d 19j5 griphoporel/a curvata (gumbel) n.comb. pia in spitz & dyhrenfurth, p. 62; pi. i, fig. 11 1920 griphoporel/a curva/a gumb. spec. pia, p. 90-92; pi. iii, figs_ 17-21 j 925 griphoporel/a curva/a diener, pi. xxviii, fig. 4 ;::: reconstruction 1964 griphoporel/a curva/a (gumbel) sokac, nikler & iv anoyic, fig. 3.3-4 1965 griphoporella clin'ora var. c/lrva/a n. val'. zan in bur l, p. 488·489; pi. 62 pars; pi. 63, fig. i pars & 2-3 1965 griplloporella c/lrvala var. cislljormis n.val zan in burl , p. 490-491; pi. 62.a·c; pi. 63, fi g. i.a-c 1965 mocroporella relica n.sp . . zanin bur l, p. 465-467; pi. 44; pi. 45; pi. 61, figs. 5·6 1967') griplwporella sp. · holzer, pi. 1, fig. 8 pars 1967 griphoporella cllrvala (gumbel) . herak, sokac & scavnicar, p. 199, n.f. 1967 griphoporello cllrl'ofo (gumbel) pia · ott, p. 222·223; pi. 13, fig. 4 1972? dasycladaeeen·resten . gusic & bab ic, pi. i, pig. 4 1975 griphoporella cllrvola (gumbel) . flug el, p. 325·327; pi. 4, rig. 6 1986 griphoporello c/ii' i'oio (gumbel) . braga, p. 245·246; pi. 2.1 1987 gripljoporello cil/tofo (gumbel) . clara pi· cj\ el ai. , p. 366 & 368; pi. xx iv, figs. 1·8; pi. xxv, fi gs. 3.b & 7.a; pi. xxvi, f igs. 2 & 5 1987 gyroporella l'esicil lijera gumbel · ciarapi· ca el ai., p. 368; pi. xxiii , figs. 1· 10; pi. xxv, fig. l.a (= xxiii, fig. 5); pi. xxv, fi gs. l.b,3 .a, 4.a, 5.a & 6.a 1987 macroporella refic({ zanin burl · c iarapi· ca el ai. , p. 364; pi. xxlj, figs. 1·8; p i. xxv , ri gs. 2.c & 6.b; pi. xxvi, 11gs. 1,3 & 7·8 1987 dasyeladaeeac gcn.ind .. ciarapica el ai. , pi. xxv ii , fi gs. 1·6 1988 griphoporella cllnala (gumbel) . sarto· rio & venturini , p. 40-41 (= p. 56, eenlre) 1988 macroparella relica zanin burl · sa rto· rio & venturini, p. 56, ballom ue,.uvgl,' .... '''.'''l,' .'vi,!. 1993 gripl/oparella clirvofa (gumbel) pia emend. . barattolo, de castro & parente, p. 23-45 (complete synonymy); pi. i , fi gs. 1· 10; pi. 2, figs. 1·8; pi. 3, fi gs . 1·5; pi. 4, figs. j ·6; pi. 5, figs. 1 -4; pi. 6; pi. 7 1995 mo eroporella relica zan in bur l = gripho­ porella cllrvafa (gu mbel) pia · pug liese, p. 537·546; pi. i, figs. 1·6; pi. 2, figs . 7· 11; pi. 3, figs. 12· 17 1997 griphoporella cllrva'" (g u m bel) pia . pugliese, p. 76; pi. 2, fi gs. 6·9 diagnosis (bara ttolo ci ai., 1993, p. 33): "cyl· indrical to slightly club-shaped simpl e thallus. primary branches only, arrangcd in vcry close, alternate whorls. the branc hes are phlo iophorous, w ith a subterminal narrow ing; the ir transverse sect ion is subc ireular. the inclina tion of the branches is 45-60° in the prox imal portion, then gradually increases outwards up to 70-80°. thc d istal port ion of the branches form a co rtex wit h po lygonal meshes horizontall y compressed. reproduc­ tive organs unknown (not calcified), probably situated in the ce ntral stem or in the primary branches (e ndo­ spore or cladosporc). the calcification constitutes a cal­ careous skele ton continllolls, very thin , enveloping to a various degree ditierent portion s or the primary branch­ es. as a consequence the pores show dirreren t mor­ phologies both in differe nt spec imens and in dirrerent portions of the samc spccimen." discussion: though not so well preserved, the zu­ mbcrak specimens (table 2) show charac te ri stics typi­ cal of thi s species, wh ich were thoroughly studied and revi sed by the above mentioned autho rs . a calcareous skeleton of irregular in terna l and ex te rnal sur race encompasses various parts o r the densely di sposed phloiopi1orous to slight ly vesiculiferous branches . the basal part of branches next to the main ax is were proba­ bly not calcified and the ex treme di stal part has bccn preserved in only some spec imens. distal branch taper­ ing, as well as the honey-comb shaped co rt ex, which barattolo et aj. (l993) mention inlheir diagnosis, dimensions in mm grgasovic (1997) flogel (1975) baratiolo et at. (1993) outer thallus diameter (d) inner thallus diameter (d) thickness of the calcareous skeleton (d-d/2) distance between whorls (h) diameter of pores (p) number of branches per whorl (w) 2.05-2.1 1 1.49-1.62 0.25-0.28 cca 0.1 cca 30 1.4-2.7 1.1-2.1 0.04-0.12 0.73-3.12 (1.98); n = 480 0.42-2.6 (1.55): n = 480 0.1-0.36 (0.22): n = 480 0.075-0.15 (0.10): n = 27 0.051 -0.24 (0.11): n = 160 12-3 1 (19.5); n = 13 tabtc 2 d imensions of grip/loporel/(i ("111"1'(1/(1 (gu mbel 1872) i3ara'ttolo e( al. 1993. the mean value is given in parel1(ileses and '"ii" refers (0 (he number of measurcments. grg:asovi~ : upper tri:lssic flioslr:l1igraph y and algae from zumbcrak (croalia) are discernible on ly in places (pi. ii , fig. 8, bottom left top right). stratigraphic range: nor ian rhaetian (barat­ tolo el ai. , 1993), confirmed also by finds from zum­ berak (triasilla halltkeni taxon-range zone). geographical distribution: austri a, croatia, ger­ many, italy, romania, spain, switzerland (baratto­ lo et ai., 1993). subtribe oligoporellinae bassoullet et al. 1979 genus physoporella (steinmann 1903) pia 1912 physoporellajollldaellsis flugel & mu 1982 pl.ll, figs. 10, 14-15 1982 physopore/la jollldacllsis n.sp. flugel & mu, p. 61-62 , pi. 8, fig. 5 pars; pi. 9, figs. 3-4 original diagnosis (flugel & mu, 1982, p. 61): "thin weakly calcified thallus with horn -like termina­ tions or the pyriform branches, arranged in vert icil s." discussion: in their morphological characteristics the zumberak specimens fully agree with those from the original description or this species. there arc some dillcrcnces in dimensions crable 3), however they arc consi stent w ith the limit s of variations known in the other species of this genus. the thallus of physopore/la jollldaclisis is cylindrical, straight (pi. ii , fig. 15), very slightly bent (pi. ii, fig. 14) or sligh tly clavate (flugel & mu, 1982, pi. 9, fig . 3). branches arc of the typical pear like piriferous type and disposed in whorls, which are the principal characteristics of the genus physoporc/la. internal branch parts, as well as the surface of the main axis were most likely not calci­ fied. calcification affects separately the external side of each branch and is complete, so that the external thallus surface is undulated. the calcareous envelope is about 0.06 mm thick. thc proximal parts of branch envelopes arc fu sed (pi. ii, fig. is, top; flugel & mu, 1982, pi. 9, fig. 3, middle part). branches in indiv idual and neighbouring whorls are densely disposed as far as their calcareous envelopes allow it. the original thallus strudimensions in mm grgasovtc (1997) 207 clure was most probably aragonitic, like in recent dasy­ c1adales, but, in the early diagenetic phases it was replaced by tiny mosaic dolomite c rystals, as other ske le tal particles in this dolomite. the phenomenon described by flugel & mu (1982) that " .. . the distal part of the thallus is covered by a thin calcareous sheet (0 .035 -0.070 mm thick) ... " has not been recorded in present material. this might be due to the diagenetic origin of this envelope in type specimens, possibly in the form of early diagenetic acicular calcite. stratigraphic range and geographic distribution: the species was originally attributed to the carnian of eastern tibet (flugel & mu 1982), and can now be extended to the norian of zumberak (au/mortlls siiiilo­ siis interval zone). order dasycladales pascher 1931 morpho tribe aciculelleae bassoullet et at. 1979 genus aciclilella pia 1930 aciclt/ella sp. pi. ll , fig. 9 the genu s acicufella was first estab lished by pia (1927), however without illustration, and later validated by pia (1930) on the basis of species aciciliella bacil­ fum. the genus is characterized by cylindrical calcare­ ous bodies with numerous spherical cavities, which are usually discernible in the sample as c ircular or elliptical sect ions. these calca reous cylinders arc assumed to represent the calcified main axis which contained repro­ duc tive organs the gametangia (pia, 1927; elliott, 1971). certain sections are very similar to the aeieu/ar­ ia genus (family acetabulariaceac), in which the repro­ ductive "umbre lla" chambers are calc ified. bystri­ cky (1975) made an extensive revision of the type species and establ ished severa l new ones, mainly on the basis of dimensions and the number of gametangia in cross section. since only one specimen was discovered from zum­ berak, and is therefore insufficient to establi sh a spe­ cies, it was defined as adell/clla sp. flugel & mu (1982) outer thallus diameter (d) 0.85-1.06 (0.96); n = 3 1.5-1 .75 inner thallus diameter (d) 0.47-0.68 (0.55); n = 3 the did relation in % 49-64 (57); n = 3 distance between whorls (h) 0.23-0.25; n = 2 diameter of pores (p) 0.11; n = 3 number of branches per whorl (w) 14; n = 1 maximal length of thallus (l) 4.9 0.8-1.3 63-77 0.12-0.25 0.15-0.22 15 ? 11.7 tab le 3 dimensions of physopore//a jomc/(f(,i1 sis flugel & mu 1982. the mean value is given in parentheses and "n" refers (0 lhe number of measurements. 208 acknowledgements this paper is a result of joint work of the "zumbe­ rak team" of the inst itute of geo logy, zagreb, to the members of which i ex tend my sincere gratitude. spe­ cial thanks arc due to dr. btanko sokac and dr. iva velie for their assistance in the dclcrminaiion of algae and foramini fera , and to dr. daniel vachard [or hi s very helpful critical review of the manuscripl. 4. references babic, lj. (i970): sphaerocodium or oneoids from the upper triassic dolomite of western yugoslavia? (sphaerocodi um iii onkoidi iz gornjolrijaskog dolo­ mita zapadn og dijela jugos lavije).geo !. vjcsn ik, 23 (1969),11 19. bab ic, lj. , gusic, i. , krystyn, l. & zupanic, j. (1980): staros! i fosili lipovac vapncnaca (lri­ jas) kod samobora, zapadno od zagreba (zur alter­ sste llung und fauna dcs lipovac kalkes (trias) bei samobor (westli ch voil zagreb)).geol. vjesnik, 31 (1979),2 1-35 . barattolo, f., de castro. p. & parente, m. (1993): some remarks on griphoporclla curvata (gumbel 1872) pia 1915, dasycladacean green alga from the upper triassic.in: bara ttolo, f. , de castro, p. & parente, m. (eds.) : studies on fossil benthic algae. bo ll. soc. paleontol. ital. , special volume, 1, 23-45, modena. bassoullet, j. -p. , bernier, p .• deloffre, r.. genot, p. , jaffrezo, m., poignant, a.f. & segonzac, g. ( 1977): classifi cati on criteria of fossil dasyciadales .in: flugel, e. (cd.): fossil algae: rcccnt results and developments. springer, 154-166, berlin. berger, s. & kaever, m.j. (1992): dasyeladales: an illustratcd monograph of a fascinating algal or­ der.thieme, stuttgart . 247 p. braga, j.c. ( 1986): upper triassic dasycladaceans in the sierra de baza (alpujarride complex , betic cor­ di llera, se spa in).n. jb. geol. pauion l. , monat ­ sheik, 4, 239-247, sluttgart. bukovac, j. , grgasovic, t. , glovacki jer­ nej. z., jerini c, g., galovic, i. & prto­ llan, b. (1995): lilostratigrafska rawamba dolo­ mitnih nas laga trij asa jugozapadnog zumberka u okviru radova na geoloskoj karti rcpubli ke hrvat­ skc 1 :50.000 (lithostratigraphic division of triassic dolomile depos its in sw zumberak mt. under the works on the geological map of the republic of croatia 1:50000).in: vlahovic, i. , velic, i. & sparica, m. (cds.): i. hrvatski geoloski kongres (first croatian geological congress), zbornik rado­ va (proceedings), 1,137-142, zagrcb. lieolog la cro:uic:t )ufl bukov ac, j. & sokac, b. (1989): 0 gornjotr i­ jaskim i donjojijaskim vapncncima sjeverne padinc gorjanaca, juzno od koslanjevice (jz siovenij a) i njihovom znacenju za tumacenje geo tekt onskih odnosa u s irem prostoru (upper triassic lower liassic limestones on the northern s lopes o f mt. gorjanc i and south of kostanjevica (sout heast slovenia) and their significance for the geotectonics of the larger area).geol. vjesnik, 42, 7-1 3. bukovac, j., velic, i. & sokac, b (1974): stratigrafski, teklonski i palcogeog rafski odnosi u podrucju dugarcsc , barilovica i skradske gore (stratigraphy, tectonics and paleogeography of the reg ion between dugaresa, barilovic and skradska gora (croatia)).geol. vjesnik, 27,59-77. bystricky, j. ( 1975): ge nu s a ciclilella pi a, 1930 (kalkalgen) in der trias der westkarpaten. geo l. sbornfk geologia carpathiea, xxviii, 1-20. ciarapica, g., cirilli , s., passeri , l. , trin­ cianti, e. & zaninetti, l. (1987): "anidrit i di burano" et "fonnation du monte cetona" (nouvelle [onnalion), biostratigraphie de deux serieslypes du trias superieur dans i' apenin septentrional.revue de paleobiologic, 6/2, 34 1-409. canovic, m. & kemenci, r. (1972): trijaski sedi ­ menli u dubokim istraznim busoti nama u vojvodini (triassic sediments in deep exploratory bornholes in vojvodina).geoloski anal i balkanskog poluoslrva, xxxvii/2, 19-31 , beograd. de castro, p. (1990): studies on the triass ic car­ bonates of the salerno province (southern italy) : the croci d ' acerno scquenee.boll. soc. geo l. ii. , 109, 187-2 17. di ener, c. (1925): leitfossilien der trias. wirbellose tiere und kalkalgen.in : gurich, g. (ed.): leit ­ fossilien, lief. 4. verlag von gebruder bornlraeger, 11 8 p, berlin. dragastan, o. (1980): alge calcaroase din mezo­ zo icul s i tertiarul romaniei. editura academi c i republicii social iste romania, bucurcsti , 169 p. durda novic, z. (1968): ei ne neue form von tro­ cho/ina aus den karnischcn ablagcrungcn slidwcst­ lieh von vojsko (s lowenien jugoslawicn).geol. vjesnik, 2 1 (1967), 105-110. elliott, g.f. (1971 ): the nature of aciculella pia (calcareous algac).paleontology, 14/4, 629-636, london. flajs , g. (1977): die ultrast rukturcn des kalkalgen­ skeletts. palaeontographica, abteilung b, 160/4-6, 69-128, stuttgart. flugel, e. (1975): kalkalgen aus riffkomplexen der alpin-medilerranen obcrtrias. beitrage zur pajaon­ loiogie und mikrofazies obertriassischcr riffe, 1. ­ verhandl. geol. bundesansl. , 2-3 (1974). 297-346, wien. grg;lwvic: uppcrtriassic ilio~lratigr:.lphy and alg;le from zumbcrak (cro:!li:!) fldgel, e. & mu , x. (1982): upper triassic dasy­ cladaccac from eastern tibet.facies, 6, 59-74. f'ucek, l. , ti slj ar, j. , sokac, b. , prtoljan, b. & ostric, n. ( 1995): postaja br. i. gornjotrijaski dolomiti u kamenolomu podsused. in: sikic, k. (eel. ): geoloski vodic medvedniee, 4 1-43, zagreb. gorjanov ickramberger , d. ( 1894): geologi­ ja gore samoborske i zumberka (geologie des samoborer und zumberak gebirge) .rad jazu , 120, 1-82, zag reb. gran ier , b. & deloffre, r. ( 1995): lnventaire critique de algues dasyeladales foss iles. iiie partie les algues dasycladalcs du pcrmien ct elu trias.­ revue de paicobiologie, 14/1 (1994 ), 49-84. grgasov1c, t. ( 1995): stratigraphy of middle and upper triass ic deposits from zu mberak mt. (w croatia).6t h international symposium on fossil algae and carbonate platform s, abstracts, 34 , ankara. gumbel, c,w. (1872): di e sogenann ten nolliporen (litholhamnium und daclylopora) und ihre bcthe­ iligung an del' zusammensetzun g del' kalkgesteine. zweitel' the il: dic null iporen des thierreichs (dactyloporieleae) nebst nachtrag zum erstcn thc­ ile. abhandlungen del' ii. classc de l' k. akademie der wi sse nsc haften, band xi, abt h. 1, 23 1-290, mlinchcn. gus ic, i. ( 1975): upper triass ic and liass ic fora­ minifera of mt. medvedni ca, northern croatia (famil ies: in volu tinidae, nubeculariidae) (gornjo­ trijaske i lijaske foralllinifcre medvedn ice, sjeverna brvatska (porodice: involutinidae, nubeculari­ idae)).pa1cont. jugos l. , 15 , 1-46, zagreb. gus1c,1. & babic, lj. (1970): neke biostratigrafske i liloge llctske osobine jure zlllllberka (some bios­ tratigraphic and lithogenetic characteri stics of the juras sic in zulllberak (nort hwestern cl'oat ia)).­ geol. vjesnik, 23 ( 1969),39-54. gus lc, 1. & babic, lj. (1972): die mikrofazies und mikrofauna del' obcrtrias und des lias des medved­ nica geb irgcs (nordkroatien).mitt. ges. geol. i3ergbaust ud., 2 1, 327-340, innsbruck. ii en rich , r. (1984): facies, dolomitizati on and kars­ tification of lagoonal carbonat es : triassic of the nonhern alps.facies, 11 , 109156. 1-\ erak, m. ( 1956) : geologija samobo rskog gorja (geologic des samoborer gebirge).acta gcol. , 1 (prir. istraz. lazu, 27), 49-73, zagreb. herak , m. ( 1957): novi nalazi sferokodija u hrvat ­ skoj i sloveniji (neue funde von sphaerocodium in kroatien und siowenien).geol. vjesnik, 10 (1956), 3 1-:18 . herak, m. ( 1968): noviji rezult ati istrazivanja osnov nih strati grafsk ih jedini c.: a u zumbcrku (neue 209 ergebn isse del' untersuchun gen von stratigraphi s­ chen baupteinhciten in zu mberak (w kroati en)).­ geol. vjesnik, 21 (1967), 111 -116. hera k, m. , malcen, z. & korol/la , b. ( 1965): prilog paleontoloskoj dokumentaciji mczozoika u sa llloborskom go rj u i si zumberku (beitrag zur pahiontoiogi schcn dokumentation des mezozo i­ kum s im samoborer gebirge und dem ne zumbe­ rak). geol. vjesnik, 18/2 (1964), 325-3 :12 . herak, m. , sokal:, b. & scavnicar , b. ( 1967): correlation of the triassic in sw lika , pakl eni ca and gorski kotar (c roat ia).geologicky sbornik , xviii/2, 189-202, bratislava. holzer, h.l. (1967): nachweis von clypeil/a miche­ lin im cordevol de l' nbrd lichen kalkalpcn. sitz. ber. osten. akad. wi ss ., math.-naturw. , abt. i, 176/5-7, 71-80, wien. kodra , b. (1972): disa te dhena stratigrafike per pre­ rjen e prozhmcs (kollates) te rajonit te valboncs.­ permbledhje studimesh, 4, 5-25, tirane. korolija , b. , fucek, l. , ostric, n. & vellc, 1. ( 1995): postaja br. 71. gornjotrijaski i senon ski sed­ imenti kod donj eg oresja.in: sikic, k. (cd.): geoloski vodic medvedn ice, 173-179, zagreb. ora vecz-sci-leffer, a. (1987): a dun,intuli -kbzc­ phegyseg triasz kepzbdm cnyeinck fo ramin i ferai (triassic foraminifers or the transdanubian cen tral range).geologica i-iungarica, series pa leontologi­ ea, so, 331 p. ott, e. (1967): dasycladaeeen (kalkalgen) aus de l' norcialpinen obcrtrias.mitl. bayer. staal ssal1ll1ll. palaont. hist. geol. , 7, 205-226, munehen. ott, e. (1972): die kalkalgen-chronologie clef alpinen milte lt rias in angieichung an di e ammo­ niten-chronologic.n. jb. geol. palaonl. , abh. , 141/ 1,81115. pantic, s. (1965): clypeilla he.iici sp. nov. iz irijask ih sedil1lenala spoljasnih dinarida (c/ypcina he§i6 sp. nov. des sediment s triasiques des dinarides exter­ nes).geoloski gjasnik, iv , 133141 , titograd. pantic, s. ( l967): mikropaleontoloske karakteristike srcdnjeg i gornjeg trijasa planine tare (zapacina srbija) (les caractcri stiques l1licropalcolltologiques du trias moyen ct supcri eur de la monta gne tara (serbi e oecidental e)) .vesnik, serija a, xxiv/ xxv (19661967),245-254, beograd. pantic, s. ( 1972): prvi nalazak trijaskih mikrofosila u oblasti mucnja, ovcara, kablara i l ei ice (za paclna srbija) (first discovery of triass ic microfossiles in the region of mu canj , ovcar, kablar and jeli ca (western serbia)). glasn ik prirodnj ackog 11luzeja, serija a, 27, 223-241 , beograd. pantic, s. (1974): prilozi 7.a st ratigrafiju trij asa pro­ kletija (con tributions to the st rati graphy or the tri210 assie of the proklctijc mountains).vesnik, serija a (gcologija) , xxxi/xxxii (1973-1974), 135-167, beograd. pantie, s, (1975): trijaskc mikrofacije dinarida. crna gora, islocna bosna i hercegovina i zapadna srbija (les microfacies triasiqucs des dinarides. le montenegro, la bosnia orientale ct ]'herzcgovine et [a serbie occidentale).drustvo za nauku i umjel­ nost erne gore, posebna izdanja, 4, 56 p., titograd. pantie, s. & rampnoux, j.p. (1972): concerning the triassic in the yugoslavian inner dinarids (sou­ thern serbia, eastern montenegro): microfacies, microfaunas, an attempt to give a paleogeographic rcconstitution.mitt. ges. geol. bergballsud., 21/1, 311-326, innsbruck. pia, j. (1920): die siphoneae verticillatae yom karbon bis zur krcide.abhandlungcn del' zoologisch­ botanischen gesellschaft in wien, band xl, heft 2, 263 p., wicn. pia, j. (1927): i. abteilung: thallophyta.in: hir­ mer, m. (eel.): handbueh del' paliiobotanik, band i. oldcnbourg, p. 31-136, miinchen and berlin. pia, j. (1930): upper triassic fossils from the burmo­ siamese frontier. a new dasycladacea, hofosporef­ fa sia/jiej/sis nov.gen., nov.sp., with a description of the allied genus aciculella pia.records of the geologia croalica 50/2 gcological survey of inelia, lxiii/i, 177-181, cal­ cuta. piller, w. (1978): involutinacea (foraminifcra) dcr trias und des lias.bcitr. palaont. osterreich, 5/l, 1-164, wicn. plenic:ar, m. & premru, u. (1977): osnovna gco­ loska karta sfrj i: 100.000, tolmac za list novo mesto l33-79. geol. zavod ljubljana (1970), say. geol. zavod, beograd, 61 p. prtoljan, b., ostric:, n., fuc:ek, l., yelic:, i. & tisljar, i. (1995): postaja br. 50. mezozojske vapnenacke stijenc u predjelu i-lorvatovc stubc markov travnik.in: sikle, k. (ed.): gcoloski vodic mcdvednice, 137-139, zagreb. pugliese, a. (1995): some observations on macrop­ orella reliea zanin bufi 1965 dasycjadacean green alga from the uppcr triassic.riv. ital. palcont. stra!., 100/4,537-546. pugliese, a. (1997): middle-late triassic dasyela­ dales (green algae) from brenta dolomites (giudi­ carie alps, italy). riv. ital. palcon!. strati ., 103/1 , 71-80. riding, r. (199 1): classification of microbial car­ bonates.in: riding, r. (ecl.): calcareous algae and stromatoli tes. springer, 21-51, berlin. plate i i 2 3 4-5,7 6 8 9 10 ii 12, [8 13 14 15-16 17 [9 microfossils from uppcr triassic dolomites from zumberak (croatia) triasillo /iall/keni majzon; black round cavity at the top is caused by bioerosion; sl ide sl 30-16/2; x 57 triasilla i/oii/kelli majzon; slide sl 30-8/18; x 57 triasilln hal1lkeni majzon with micritic cnvelope, probably of cyanobacterial origin; slide sl 30-3/3; x 36 all/%rlllsjried/i (kristan-tollmann); sl ides sl 30-8/15, sl 30-8/2 and sl 30-27/1; x 57 all/%rliis /cllllis (kristan); slide sl 30-24/1; x 57 au/%r/us silllloslis weynschenk, equatorial section; slide sl 30-8/17; x 45 aii/%r/lls silluoslls weynschenk, axial section; slide sl 2i 2/13; x 57 au/%r/us cf. silllloslls weynschenk, axial section; slide sl 30-20/2; x 57 trochammina sp. and aufoto/"lus sinuosus weynschenk; slide sl 30-30/1; x 57 ail/ocoilils permodiscoides (oberhauser); slide sl 30-21/2 and sl 30-14/1; x 57 aii/%r/lls cf. /ilmidlis (kristan-tollmann); slide sl 30-8/1; x 57 aii/olorlils //iiliie/lis (kristan-tollmann); slide sl 30-8/1; x 57 lameilicolllls mll//ispil'lls (oberhauser); slide sl 3-5/x and sl 3-5ni; x 31 lamei/iconlls procerlls (l1ebus); slide sl 3-5/xyli; x 31 ?parafavrcilla r/joronclcnsis bronnimann et al.; slide sl 25-9; x 22 plate i 211 rblll, u., dumont, t., von rad, u., martini, r. & zaninetti, l. (1991): upper triassic tet­ hyan carbonates on northwest australia (wombat plateau, odp leg 122). facies, 25, 211 -252. salaj, j., borza, k. & samuel, o . (1983): tri­ asssic foraminifers of the west carpathians.geo­ logicky ustav dionyza stllra, 213 p., bratislava. salaj, j. , trifonova , e. & gheorghian, d. ( 1988a): a biostratigraphic zonation based on ben­ thic foraminifera in the triassic deposits of the carpatho-i3alkans.revue de paicobiologie, vol. spec, 2 (benthos '86), 153-159. salaj, j., trifonova, e., gheorghian, d. & coroneou, v. (1988b): the triassic foramini­ fera microbiostratigraphy of the carpathian balkan and hell cnic realm.mineralia slov., 20/5 (1988), 387-41) u'-''''''b'' ' '--,v ... , ,,,, .'v," sartorio, d. & venturini, s. (1988): southern tethys biofacies.agip, 235 p., milano. schafer, p. & senowbari-daryan, b. (1983): die kalkalgen aus der obertrias von hydra, grie­ chenland.palacontographica, abt. b, 185/4-6, 79142. sokac, b. & t. grgasovic (1995): dissocladello hystrickyi 11. sp., a new calcareous alga (dasycla­ daceae) from upper triassic dolomites of mt. med­ vednica (northern croatia) .geologia croatica, 48/1 , 1-5. sokac, b. & grgasovic, t. (1998): aslerocolcl/­ ills heraki n.gen., n.sp., a new ca lcareolls alga (gymnocodiaceae) from the upper triassic haupt­ dolomite of zumberak, north croatia.facies, 38, in press . plate ii microfossils from upper triassic dolomites from zumberak (croatia) microfacies of intcrval-zone aulofor/lis sillllosus: aulolor/lis silllloshs weynschenk (left and right) ancl al/lolol'll/sli-iedli (kristan-tollmann) (m iclclle); slicle sl 12-34a; x 22 2 microfacies of taxon-range zone c/ypeil/a besici: clypeina hesici pantie, transversal, slightly ob lique sections; sl icle sl 212c/ii; x go ::\ microfacics of taxon -range zone triasina /wntkeni: triasino flall/keni majzon (right), aii/oforflls fiiedli (kristan-tollmann) (clown) ancl gymnocodiacea inclel. (left); slicle sl 30-8/2; x 36 4 clypeina he."iici pantie, fragment of obliquc section (left) and dasyc!adacea indct., oblique section with visible phloiopilorous branches (down right); slide sl 3-s/vi; x 31 .') clypeilla hesici pantie, oblique section (down) and au/otorflfs silllfoslfs \veynschenk (up); slide sl 3-)/iv; x 28 6 clypeilla besici pantic, longitudinal section through a whorl; slide sl 3-sn; x 31 7 clypeilla hesici pantic, tangential scction through a whorl; slide sl 3-6/1, x 31 8 griphoporello curvala (gumbel), transversal , slightly oblique section; slide sl 30-8/12; x 31 9 acicllic//o sp., transversal section; slide sl 3-s/ii; x 31 10 pllysoporella jomdaellsis flugel & mu, transversal, slightly oblique section; slide sl 19-1 5/iv; x 22 i 1-12, 18 ciyl'cillo hesici pantic, transversal sections; sl icles sl 3-5/x1, sl 3-5/xii ancl sl 2-12d: x 31 13 criphupure/lo cllrvala (gumbel), oblique section; slicle sl 30-813; x 31 14 physopore//ajollldoellsis flugel & mu, longitudinal sec tion; slide sl 17-9; x 17 15 physopore//a jomdael/sis flugel & mu, longitudinal section; slide sl 19j sly; x 22 i g c/ypeino besici p antic, fragment of transversal, slightly oblique, section; slide sl 3-s/xii; x 31 17 clypeillo besici pantic, oblique section; slicle sl 3-s/ix; x 31 19 clypc/i/o besici pantie, transversal section, possibly of the top part of the thallus; sl ide sl 3-s/ii; x 31 plate ii 2 13 sokac, b. , nikler, l. & ivanovic, a. (1964): fund von obertriadischen dasycladaceen im gebiet des velebit.bull. sc i. acad. yougosl., sect. a, 9/6, 156157, zagreb. spitz, a. & dyhrenfurth, g. (1915): monogra­ phi e der engadiner dolomiten zwischen schuls, scanfs und dem stilfserjoch.beitrage zur geologis­ chen karte der schweiz, 44, 62, bern. sikic, k. , basch, o. & simunic, a. (1979): osno­ vna geoloska karta sfrj i: 100.000, tumai' za list zagreb l38 -80. institut za geol. istrai., zagreb (1972), say. geol. zavod, beograd, 81 p. simunic, an. & simunic, ai. (1997): triassic deposits of hrvatsko zagorje.geologia croatica, 50/2,243-250. vachard, d., colin , j. -p., hochuli, p.a. & rosell, j. (1990): biostratigraphie, foraminiferes, palynoflore et ostracodes du rhotien de bac grillera ljeologm lroatica :jut l (pyrenees orientales espagnoles).geobios, 23/5, 521-537, villeurbanne. vachard, d. & fontaine, h. (1988): biostrat i­ graphic importance of triassic foraminifera from south-east asia.revue de paleobiologie, 7/1, 8798. zanin burl, c. (1965): il trias in lombardia (studi geologici e paleontologici). xm. le alghe calcaree delle prealpi lombarde.riv. ital. paleont, 71/2, 449-554. zaninetti, l. (1976): les foraminiferes du trias. essai de synthese et correlation entre les domaines mesogeens europeen el asiatique.riv. hal. pale­ ont., 82/1,1-258. manuscript received april 14, 1997. revised manuscript accepted november 10, 1997.  robustoconus tisljari n. gen., n. sp., a new larger benthic foraminifer from the middle jurassic (early bajocian) of the adriatic carbonate platform of croatia  felix schlagintweit1, ivo velić2 and branko sokač3 1 lerchenauerstr. 167, d-80935 münchen, germany; (felix.schlagintweit@gmx.de) 2 croatian geological summer school and geolog d.o.o., pančićeva 5, hr-10000 zagreb, croatia (ivo. velic@zg.t-com.hr) 3 croatian geological survey, sachsova 2, hr-10000 zagreb, croatia doi: 10.4154/gc.2013.02 geologia croatica 66/1 15–28 11 figs. 4 pls. zagreb 2013 geologia croaticageologia croatica 1. introduction larger benthic foraminifera are widely distributed in jurassic shallow-water carbonates of the adriatic carbonate platform, i.e. the karst dinarides (e.g. radoičić, 1966; nik ler & sokač, 1968; gušić, 1969a, b, 1977; velić, 1977, 2007; gušić & velić, 1978; velić & sokač, 1978; schlagintweit & velić, 2011). during recent investigations of aalenian–bajocian limestones of biokovo mt. and dubrovnik area, new and poorly known taxa were described by schlagintweit & velić (2011). previously, the middle jurassic shallow-water carbonates of the karst dinarides were considered to be poor in benthic foraminifera. the aforementioned investigations however, have shown that these are distinctly richer in taxa than the lower jurassic strata, with many of these representing index forms (velić, 2007). in the framework of on-going studies, another new middle jurassic larger benthic foraminiferan is recognized, described as robustoconus tisljari n. gen., n. sp. 2. geological setting the middle jurassic platform carbonates containing robustoconus tisljari n. gen., n. sp. crop out near osojnik in the vicinity of dubrovnik, southern croatia (fig.1). tectonically, they belong to the southwestern marginal area of the adriatic carbonate platform (vlahović et al., 2005). these carbonates were deposited in shallow water environments strongly influenced by currents and waves, with the ab stra ct the new larger benthic foraminifer robustoconus tisljari n. gen., n. sp. is described from middle jurassic (early bajocian) high-energy shallow-water limestones of the dubrovnik area in the south-eastern part of the adriatic carbonate platform. robustoconus represents a large dimorphic agglutinated foraminiferan with a coarse exoskeleton typical of representatives of the family hauraniidae. differences to the allied genera spiraloconulus allemann & schroeder and bostia bassoullet are discussed. the occurrence of a further new genus of larger foraminifera provides additional evidence for a high origination rate in the middle jurassic. the restriction of robustoconus tisljari to the timodonella sarda taxon-range zone highlights its biostratigraphic interest. keywords: benthic foraminifera, systematics, middle jurassic, adriatic carbonate platform, croatia geologia croatica 66/1geologia croatica 16 occasional development and destruction of patch reefs (see schlagintweit & velić, 2011, for more details). in general, they are represented by various types of skeletalintraclastic/bioclastic grainstones and oncoidal facies, with abundant tests of larger benthic foraminifera. this early middle jurassic profile lies ca. 1 km southsoutheast of osojnik, on the road connecting the village with dubrovnik (figs. 1–2). abundant specimens of r. tisljari n. gen., n. sp. occur in thick bedded skeletal-intraclastic/bioclastic grainstones (sample o-26; fig. 3), ca. 20 metres above the last occurrence of timidonella sarda bassoullet, chabrier & fourcade (see osojnik section – schlagintweit & velić, 2011). 3. systematic palaeontology the suprageneric classification of agglutinated-conical benthic foraminifera (= pro parte the so-called „larger agglutinated foraminifera”) provided by loeblich & tappan (1987) was criticised recently by vecchio & hottinger (2007) as not taking into account the architecture of the exoand endoskeletal elements and their pattern. such a scheme was introduced some decades ago by septfontaine (1988) and was incorporated in the „year 2000 classification” of kaminski (2004) that is followed here. class foraminiferida order loftusiida kaminski & mikhalevich, 2004 suborder orbitolinina kaminski, 2004 superfamily pfenderinacea smout & sudgen, 1962 family hauraniidae septfontaine, 1988 subfamily amijiellinae septfontaine, 1988 genus robustoconus nov. gen. origin of the name: robustus (lat.) = robust and conus (lat.) = cone. named after the high-conical test (aand most b-forms), combined with the thick, coarse hypodermal network. diagnosis: test conical to cylindrical, with an early plani spiral and involute coiled stage, later rectilinear. cone base slightly arched in the juvenile stage, becoming distinctly convex in adult chambers. macrospheric specimen with a small simple subspherical proloculus. microspheric tests, large and may be slightly flabelliform. wall microgranular calcareous, agglutinated, and may include large grains especially in the central part. chambers subdivided into a marginal and central zone. coarse exoskeleton of radial (beams and intercalary beams) and horizontal partitions (rafters) forming a network of chamberlets in the marginal zone. the complex cen tral zone consists of anastomizing septal excrescences (with constrictions and swellings) that reach into the chamfigure 1: geographic position of the investigated osojnik profile ca 5 km north of dubrovnik, in southern croatia (asterisk). schlagintweit et al.: robustoconus tisljari n. gen., n. sp., a new larger benthic foraminifer from the middle jurassic (early bajocian) ... geologia croatica 17 ber interior, but do not span between two succesive septa, leaving instead a continuous open space at the proximal parts of the chambers. this peculiar type of endoskeleton that strong ly reduces the volume of the chamber interior may be obscured in specimens where large amounts of agglutinated particles are incorporated in the test. intracameral foramina single, interiomarginal in the coiled part, becoming multiple, irregularly distributed in the central zone of the rectilinear part. type species: robustoconus tisljari nov. sp. comparisons: robustoconus belongs to a group of large ben thic foraminifera exhibiting a „structure exosqueletique complexe grossiere“ (hottinger, 1967) or hauraniiform subepidermal network (réseaux hypodermique) (septfontaine, 1980). these forms are included in the family hauraniidae septfontaine (see kaminski, 2004). robustoconus can be compared with spiraloconulus allemann & schroeder, 1972, and the allied genus bostia bassoullet, 1998, as well as with timidonella bassoullet, chabrier & fourcade, 1974. with respect to timidonella, only cylindriform macrospheric specimens (e.g. velić, 2007: pl. 6, fig. 3) can be taken for comparison given that the microspheric generation is characterized by discoidal tests (bassoullet et al., 1974). timidonella possesses an endoskeleton of pillars connecting consecutive septa. the differences of robustoconus to both spiraloconulus and bostia are more delicate needing comprehensive discussion. spiraloconulus differs from robustoconus by the construction of its exoskeleton consisting of a rather narrow marginal zone of thin-walled chamberlets and a large central zone with septa typically agglutinating large grains (allefigure 2: geographic map (dubrovnik sheet, no. 625-3-1), scale 1:25.000 showing the location of sample o-26 containing the holotype of robustoconus tisljari n. gen., n. sp. near osojnik. geologia croatica 66/1geologia croatica 18 mann & schroeder, 1972; cherchi & schroeder, 1981) (fig. 4). in fact, the central zone is „relatively simple“ in spiraloconulus where the „partly coarse agglutination of the chamber floors (remark: roofs!) can easily be mistaken for a complex structure“ (allemann & schroeder, 1972: p. 207). this statement was given for the type-species s. perconigi where the agglutination of foreign material is concentrated within the septa and the chamber interior is more or less free. in s. giganteus, the chamber interior of micropsheric specimens may be largely filled with figure 3: lithostratigraphy of the osojnik section and the distribution of important larger benthic foraminifers, with the position of robustoconus tis ljari n. gen. n. sp. (sample o-26). schlagintweit et al.: robustoconus tisljari n. gen., n. sp., a new larger benthic foraminifer from the middle jurassic (early bajocian) ... geologia croatica 19 ooids connected to the septa and to adjacent ooids by means of very thin walls as a biomineralized part of the test. notwithstanding, boudagher-fadel (2008: p. 179) defines the genus spiraloconulus as possesing an „endoskeleton(s) of pillars from septum to septum“ obviously adopting the classification of loeblich & tappan (1987), placing the genus within the pillaroid family spirocyclinidae. in fact, spiraloconulus (and also bostia) is placed in the subfamily amijiellinae (septfontaine, 1988; kaminski, 2004) where representatives usually do not develop pillars. the central zone of robustoconus is made up of a complex structure of anastomizing micritic septal excrescences (with constrictions and swellings) that reach deep into the chamber lumen (= trabécules micritiques of bassoullet, 1998). however, they do not span between two succesive septa, instead leaving a continuous open space at the proximal parts of the chambers. therefore these cannot be termed interseptal pillars (see hottinger, 2006). this type of endoskeleton is often obscured in specimens where large amounts of agglutinated particles are incorporated in the tests of robustoconus. in bostia, bassoullet (1996) speaks of an agglutinated endoskeleton. for the genus limognella (see below), septfontaine (1988: p. 244) assumes that such an endoskeletal structure is only pretend due to the highly figure 4: spiraloconulus giganteus cherchi & schroeder from the bajocian of mount biokovo, croatia. a) oolitic grainstone with two specimens. b) longitudinal section. note the simple central zone composed of large individual ooids that in the lower test portion stretch between two successive septula. c) longitudinal section. note ooids (white arrow) and small benthic foraminifer (black arrow) attached to the chamber rooves. scale bars 0.5 mm. figure 5: a) grainstone with abundant robustoconus tisljari showing moderate parallel orientation of their cylindroconical tests. thin-section 0-26/5. scale bar 1 mm. b) two specimens of robustoconus tisljari in longitudinal section, the left one showing an initial spire with protoconch (p). note the different dimensions and the difference in chamber convexity resulting in a more flattened (left) or convex apertual face (right) in large specimen. the specimen on the right (outlined by the dashed white-line) occurs in a packstone intraclast. thin-section 0-26/6. scale bars 0.5 mm. geologia croatica 66/1geologia croatica 20 agglutinated character. in this respect, returning to the genus spiraloconulus, the type-species s. perconigi can be considered as a species with no endoskeleton, whereas the short micritic walls connecting adjacent agglutinated grains in s. giganteus can be considered as endoskeletal structures. concerning the development of the macrospheric embryo, it is uncertain whether in robustoconus it is unilocular or bilocular, e.g. as in spiraloconulus perconigi (see allemann & schroeder, 1972). in any case it is not complex as in timidonella, orbitopsella, cymbriaella or bostia, composed of a rather large single spherical proloculus that is enclosed by a thin wall and a large spheroconch (e.g. bassoullet et al., 1974; bassoullet, 1998; fugagnoli, 1999). in most cases, a single subspherical proloculus is observable in robustoconus with a diameter of 0.1 to 0.2 mm, distinctly smaller than the giant spheroconch of bostia with a size of 0.6 to 1.0 mm (bassoullet, 1996: p. 192). in rare cases, a second crescent-shaped chamber, slightly separated from the proloculus is discernible in robustoconus that is interpreted as the first post-embryonic chamber rather than a deuterconch. let us remember that structural differences in the embryonic apparatus are widely accepted criteria in larger benthic foraminifera. besides the giant complex embryonic apparatus in bostia, this species also differs from robustoconus by the distinctly reduced to absent initial spire. it should be mentioned that kaminski (2000: p. 269) considers bostia „to represent a more advanced stage in the evolution of the spiraloconulus lineage“. last but not least, we also have to mention the genus limognella pelissié & peybernès, 1982. whereas cherchi & schroeder (1983) consider limognella a synonym of spiraloconulus, bassoullet (1999: p. 193) stresses morphological differences. a third view was expressed by septfontaine (1988: p. 244) regarding limognella a synonym of alzonella bernier & neumann, 1970. however, pelissié & peybernès (1982: pl. 2, fig. 7) illustrated a single transverse section of a microspheric forms of limognella exhibiting a flattened test with subparallel opposite sides. transverse sections of spiraloconulus are almost exlusively round (cy lin drical enrolled part), and slightly elliptical shapes can only be observed in exceptional cases. there are also examples where test compression is used for genus differentiation, e.g. planisepta (septfontaine in kaminski, 2000) versus lituosepta cati, 1959. the occurrence of both orbitoliniform (s. perconigi) and ammobaculitoid forms (s. giganteus) within the same genus, however, makes the test morphology highly problematic as a generic criterion. robustoconus tisljari nov. sp. (figs. 5–10; pls. 1–4) origin of the name: in memory and dedication to josip tišljar for his numerous contributions to geology, especially to the carbonate sedimentology of the adriatic carbonate platform (i.e. karst dinarides in croatia, slovenia, bosnia and herzegovina, and montenegro). holotype: longitudinal section illustrated in fig. 6a, c thin-section 0–26/3. paratypes: all other specimens illustrated in the present paper. material: from sample 0–26, 11 thin-sections (2.5 x 7.5 cm) were made, numbered 0–26, 0–26/1 to 0–26/10 each containing about 40 to ~70 variously sectioned specimens. depository: croatian natural history museum, demetrova 1, 10000 zagreb, croatia. figure 6: robustoconus tisljari nov. gen., n. sp. from the early bajocian of croatia. a) longitudinal specimen of a macrospheric specimen with short initial spire, holotype. the upper part passes obliquely through the reticular network. thin-section 0-26/3. scale bar 1 mm. b) longitudinal section. thinsection 0-26. scale bar 1 mm. c) detail from a showing four chambers without endoskeletal pillars connecting subsequent septa. note the numerous horizontal marginal plates. scale bar 0.3 mm. d) detail from c showing the free spaces at the proximal parts of the chambers. scale bars 0.3 mm. figure 7: robustoconus tisljari nov. gen., n. sp. from the early bajocian of croatia. a) slightly oblique axial section through the planispiral involute initial spire of a megalospheric specimen. thin-section 0-26/1. scale bar 0.3 mm. b) equatorial section through a juvenile specimen only consisting of the initial planispiral part. note the interio-marginal intercameral foramina (arrows). thin-section 0-26/5. scale bars 0.3 mm. schlagintweit et al.: robustoconus tisljari n. gen., n. sp., a new larger benthic foraminifer from the middle jurassic (early bajocian) ... geologia croatica 21 plate 1 robustoconus tisljari, different longitudinal, tangential (a-j) and oblique sections (k-m), mostly of supposedly microspheric specimens; figure j shows a megalospheric specimen. early bajocian of croatia. a two specimens in oblique longitudinal section. note the irregular growth of the uppermost part of the test (arrows) of the specimen on the right. thin-section 0-26/5. b oblique longitudinal section. thin-section 0-26/10. c oblique longitudinal section. thin-section 0-26/2. d longitudinal section. thin-section 0-26/2. e longitudinal section. thin-section 0-26/4. f longitudinal section; note the initial test bending. thin-section 0-26/5. g oblique longitudinal to tangential section. thin-section 0-26/4. h oblique longitudinal section. thin-section 0-26/4. i longitudinal-tangential section. thin-section 0-26/10. j longitudianl section of a juvenile specimen showing initial spire with proloculus. thin-section 0-26/8. k oblique section. note the micritic endoskeletal structure of the central zone devoid of agglutinated material (see also fig. l). thin-section 0-26/1. l oblique section of a test with an elliptical enrolled part. thin-section 0-26/2. m oblique section, thin-section 0-26/1. scale bars 0.5 mm. geologia croatica 66/1geologia croatica 22 plate 2 robustoconus tisljari, different sections of macrospheric specimens. early bajocian of croatia. a oblique longitudinal section of specimen showing initial spire with proloculus. thin-section 0-26/5. b longitudinal section of specimen showing initial spire and proloculus. thin-section 0-26/10. c oblique longitudinal section passing through the proloculus. thin-section 0-26. d oblique longitudinal section of specimen showing initial spire with proloculus. thinsection 0-26/2. e oblique section passing through the proloculus. thin-section 0-26/5. f longitudinal-tangential section cutting the proloculus marginally. note the subparallel longitudinal orientation of the micritic endoskeletal elements devoid of agglutinated particles (see also fig. d). thin-section 0-26/8. g oblique section passing through the initial spire and proloculus, thin-section 0-26. h-i longitudinal section cutting the initial spire (with about 9 chambers in h) and proloculus. thin-sections 0-26/5 and o-26/8. j-l oblique section through the initial part with proloculus. thin-sections 0-26/4, and o26/2 (k-l). m note the sickle-shaped first post-embryonic chamber (pec). thin-section 0-26/2. scale bars 0.5 mm. schlagintweit et al.: robustoconus tisljari n. gen., n. sp., a new larger benthic foraminifer from the middle jurassic (early bajocian) ... geologia croatica 23 plate 3 robustoconus tisljari, transverse to slightly oblique transverse sections of small specimens. early bajocian of croatia. a thin-section 0-26/7. b thin-section 0-26/2. c thin-section 0-26. d thin-section 0-26/2. e thin-section 0-26/3. f thin-section 0-26. g thin-section 0-26/9. h thin-section 0-26/4. i note the large agglutinated grains (amongst a small textulariid foraminifer) in the central zone. thin-section 0-26/5. j thin-section 0-26/5. k thin-section 0-26/5. l thin-section 0-26/6. m thin-section 0-26/6. n thin-section 0-26/7. o thin-section 0-26/8. p thin-section 0-26/9. q thin-section 0-26/8. r thin-section 0-26/10. s thin-section 0-26/8. scale bars 0.5 mm. geologia croatica 66/1geologia croatica 24 plate 4 robustoconus tisljari, transverse to slightly oblique transverse sections of large specimens. early bajocian of croatia. a thin-section 0-26/4. b note the strongly reduced chamber volume resulting from the dense and thick anastomizing endoskeletal network. thin-section 0-26/2. c note the transect of part of the septum with irregular distributed tiny foramina (white dashed circle). thin-section 0-26/2. d thin-section 0-26/3. e thin-section 0-26/3. f thin-section 0-26/6. g thin-section 0-26/7. h note the anastomosing septulae (as) of the central zone. thin-section 0-26/5. i thin-section 0-26/7. j thin-section 0-26/7. k thin-section 0-26/9. l note the transect of part of the septum with irregular distributed tiny foramina (white dashed circle). thin-section 0-26/8. scale bars 0.5 mm. schlagintweit et al.: robustoconus tisljari n. gen., n. sp., a new larger benthic foraminifer from the middle jurassic (early bajocian) ... geologia croatica 25 figure 8: robustoconus tisljari nov. gen., n. sp. from the early bajocian of croatia. a) oblique section of a large microspheric flabelliform test. thin-section 0-26/2. b) oblique axial section of a megalospheric specimen passing through the initial spire and the proloculus. note the aberrant test excrescence (branching). thin-section 0-26/3. c) oblique longitudinal section of a microspheric specimen with large agglutinated micritized lithoclasts. the arrow points to a lithoclast incorporated into the marginal zone that lacks a network in this part. note the irregular test growth. thin-section 0-26. d) oblique section of a slightly flabelliform test. thin-section o 26-6. e) specimen with irregular morphology, most likely resulting from partial test damage (arrows) that was not fatal enabling ongoing chamber formation. thin-section o 26-7. f ) oblique transverse section of a specimen exhibiting a marginal test irregularity (upper side). thin-section o 26-8. scale bars 0.5 mm. figure 9: robustoconus tisljari nov. gen., n. sp. from the early bajocian of croatia. a-c) oblique sections, most probably all microspheric specimens. note the thick dense and vermiform network of partitions in b. in c, four chambers are obliquely transacted and the network becomes continuously coarser from the marginal parts towards the chamber interior. thin-sections 0-26/8, 0-26/4 and 0-26/7. scale bars 0.5 mm. type-locality: the road cut on the eastern slope of sv. ilija hill, ca. 1 km sse from osojnik, on the road from osojnik to dubrovnik (gps, x=6506425, y=4728797; fig. 2). type-level: thick bedded, light-brownish coloured to white skeletal-intraclastic/bioclastic grainstone/rudstone lime stone of lower bajocian age. diagnosis: being monospecific so far, the species diagnosis corresponds to the genus diagnosis. description: test high conical to cylindrical, with an early planispiral and involute coiled stage, later rectilinear in specimens attributed to megalospheric forms (e.g., fig. 6a, pl. 2b, d). occasionally, tests with irregular protuberances („pseudo-branching”) at the ventral side (fig. 8b) or slightly flabelliform outline (figs. 8d-e) are observed in addition. geologia croatica 66/1geologia croatica 26 the test height of adult specimens is most frequently within the range of 1.7 mm to 2.5 mm. the greatest observed specimen measures 5.9 mm in height and 1.54 mm in diameter (pl. 1a). the short initial planispirally involute coiled part (height ~0.3 to 0.5 mm) consists of about one (? one and a half) whorl(s) of low crescent-shaped chambers (5 to 10 in number). this part may be apical or eccentric in position. transverse sections through the enrolled part are approximately circular to slightly elliptical. in the coiled part, the intracameral foramina are single and interio-marginal in position (fig. 7b). the macrospheric proloculus is simple with a diameter of ~0.1 mm to ~0.2 mm (most values between 0.13 and 0.16 mm). in sections parallel to the plane of coiling the shape of the proloculus is subspherical, whereas in sections perpendicular to the plane of coiling it appears ovally compressed (fig. 6a). the proloculus is followed by a second crescent-shaped chamber closely attaching the proloculus (pl. 2, fig. m). it is interpreted as the second post-embryonic chamber rather than as a deuteroconch. the uncoiled rectifigure 10: robustoconus tisljari nov. gen., n. sp. from the early bajocian of croatia. a-j) oblique and tangential sections passing through the epidermal network of beams and rafters. from the marginal part towards the chamber interior, the network becomes successively coarser. note also the thickening at the junction points. s = septum (f ). thin-sections 0-26/5 (a, e), 0-26/4 (b), 0-26/7 (c), 0-26/9 (d, i), 0-26/1 (f ), 0-26/8 (g), 0-26/10 (h, j). scale bars 0.5 mm. linear stage corresponds to the main part of the test with up to about 15 uniserial chambers. during ontogeny, the almost flat chamber base successively becomes distinctly convex as appears also the ventral surface of the cone. in transverse sections, the rectilinear part is round, occasionally slightly elliptical (pls. 3–4) and in rare cases also with some marginal embayments visible in transverse section (fig. 8f). other test irregularities may result from very large agglutinated particles (fig. 8c). each chamber is subdivided into a marginal zone and a central zone (pls. 3–4). the marginal zone consists of radial partitions (beams and 1 to 2 intercalary beams) and short horizontal partitions forming a network of chamberlets (fig. 9). the diameter of these chamberlets exhibiting polygonal outlines varies between 0.06 and 0.08 mm in shallow tangential sections. towards the chamber interior, the chamberlets increase in size along with a thickening of the exoskeletal elements. there may be 2 to 3 (rarely 4) rows of cham berlets per chamber displaying an irregular alternating position (fig. 8c, upper part). schlagintweit et al.: robustoconus tisljari n. gen., n. sp., a new larger benthic foraminifer from the middle jurassic (early bajocian) ... geologia croatica 27 the central zone is made up of rather thick micritic septal excrescences (with constrictions and swellings) showing a general subparallel orientation toward the test axis (e.g. pl. 2f). as visible in transverse sections, they form an anastomosing network (pls. 3–4). this structure forms a peculiar type of endoskeleton that may occupy large parts of the chamber lumen (e.g., pl. 4b). the amount and also the size of agglutinated grains is rather variable. in many cases these grains are clearly recognizable as small lithoclasts with micritic rims or small benthic foraminifera (fig. 8c, pl. 3i, p). homogeneous micritic grains (peloids) may also be agglutinated and are often indistinguishable from thickenings of the endoskeletal elements. in longitudinal sections, a continuous open space in the proximal part of the chamber base is discernible (fig. 6, pl. 1c-e). no interseptal structures (pillars) are present. laterally, the endoskeletal elements fuse with those of the exoskeleton. in the uniserial stage, there are numerous tiny intercameral foramina (width about 0.01 to 0.03 mm) piercing the septa and exhibiting an irregular distribution throughout the middle part of the central zone (pl. 4c, l). remarks: irregular aberrant tests as observed in robustoconus are reported for instance from the middle jurassic bostia irregularis (bassoullet, 1998), the upper jurassic anchispirocyclina (ramalho, 1971) or the lower cretaceous torremiroella (brun & canérot, 1979). the reasons for these abnormalities are unknown. tests of spiraloconulus giganteus displaying both irregular internal struc tures and external morphologies were reported by cherchi & schroeder (1981) resulting from large agglutinated ooids. in another case, partial test damage of robustoconus tisljari (fig. 8e) was the most likely cause of unusual growth. test abnormalities are also reported from modern benthic foraminifera. they may be related to environmental stress conditions, e.g., warm water sources in deep sea areas (meriç et al., 2003) or other factors (see for example, mukhopadhyay, 2012). a test dimorphism is assumed for robustoconus. this can be suggested from specimens with a clear pronounced proloculus in a given size range (pl. 2), whereas in other specimens it is not detectable in longitudinal sections. megalospheric forms are usually high-cylindroconical, whereas slightly flabelliform tests can be referred to b-forms (fig. 8d-e). another indication was obtained from the size dimensions. in thin-sections, 242 transverse sections were measured resulting in a range from 0.32 to 1.54 mm for the test width (fig. 11). the data show two maxima, from which the smaller one (between 0.6 and 0.65 mm) is attributed to macrospheric specimens. however, it must be noted that this is only an interpretation, as from the inner structure the two generations cannot be distinguished. therefore the data are assumed as representing a mixture of both generations and adult/juvenile specimens within a given assemblage. stratigraphy: according to the foraminiferal assemblage at the type locality (fig. 3), the stratigraphic range of robustoconus tisljari n. gen. n. sp. can be considered as ear ly bajocian. microfacies: sample 0–26 represents an intraclastic grain stone clearly dominated by the overall presence of tests of robustoconus tisljari (fig. 5). other foraminifera include common textulariids and some rare specimens of bosniella bassoulleti schlagintweit & velić. calcareous algae are very rare and are only represented by scattered porostromate algae and rare debris of an unknown tiny clypeina species. remains of gastropods (including nerineids) are common. acknowledgment field and laboratory investigations were supported by the croatian geological survey and the croatian ministry of science, education and sports of the republic of croatia, through projects 195-1953068-0242 „microfossil assemblages in carbonate deposits of the karst dinarides” and 1811811096-1093” basic geological map of the republic of croatia 1:50.000”. antonietta cherchi (cagliari) and kemal tasli (mercin) are thanked for their remarks that encouraged us to better clarify some details of the manuscript. we would also like to thank julie robson (open university) for the language review. figure 11: test diameter (mm) of robustoconus tisljari in transverse sections showing two separated maxima and their interpretation in terms of different generations (aor macrospheric and bor microspheric). number of measured specimens = 242. further explanations in the text. geologia croatica 66/1geologia croatica 28 references allemann, f. & schroeder, r. (1972): spiroconulus perconigi n. gen. n. sp. a new middle jurassic foraminifer of oman and spain. – rev. espan. micropal. num. extraord., 199–203. banner, f.t., whittaker, j.e., boudagher-fadel, m.k. & samuel, a. (1997): socotraina, a new hauraniid genus from the upper lias of the middle east (foraminifera, textulariina).– revue de micropaléontologie, 40/2, 115–123. doi.org/10.1016/s00351598(97)90514–6 bassoullet, j.-p. (1998): un nouveau grand foraminifère bostia irregularis n. gen., n. sp. (lituolacea, hauraniidae) du jurassique moyen de dordogne (france).– revue de micropaléontologie, 41/3, 181–195. doi: 10.1016/s0035-1598(98)90164-7 bassoullet, j.-p., chabrier, g. & fourcade, e. (1974): timidonella sarda n. gen., n. sp., nouveau lituolidé (foraminifère) du dogger.– c. r. acad. sc. paris, 279, 2015–2018. bernier, p. & neumann, m. (1970): alzonella cuvillieri n. gen., n. sp., nouveau genre de foraminifère du bathonien de la bordure méridionale des cévennes.– revue de micropaléontologie, 13/1, 3–12. brun, l. & canérot, j. (1979): torremiroella hispanica n. gen., n. sp. un nouveau lituolidé (foraminifère) du barrémien supérieur du maestrazgo (espagne).– bull. cent. rech. explor.-prod. elfaquitaine, 3/2, 311–335. cati, f. (1959): nuovo lituolide nei calcari grigi liassici del vincento.– giornale di geologia, ser. 2, 7, 1–10. cherchi, a. & schroeder, r. (1981): spiraloconulus giganteus n. sp., a new lituolid foraminifer from the dogger of nw sardinia (italy).– bolletino della società paleontologica italiana, 20/2, 163– 168. cherchi, a. & schroeder, r. (1983): remarks on spiraloconulus giganteus cherchi & schroeder, 1982 and limognella dufaurei pelissié & peybernès, 1982.– géobios, 16/2, 249–250. doi: 10.1016/s0016-6995(83)80024-2 fugagnoli, a. (1999): cymbriaella, a new foraminiferal genus (textulariina) from the early jurassic of the venetian prealps (northeastern italy).– revue de micropaléontologie, 42, 99–110. doi. org./10.1016/s0035-1598(99)90102-2 gušić, i. (1969a): some new and inadequately known jurassic foraminifera from central croatia.– geol. vjesnik, 22, 55–88. gušić, i. (1969b): biostratigraphic and micropaleontologic characteristics of some jurassic cross-sections in central croatia.– geol. vjesnik, 22, 89–97. gušić, i. (1977): a new foraminiferal family, biokovinidae, from the jurassic of the dinarides and its phylogenetic relationships.– palaeont. jugoslavica, 18, 7–31. gušić, i. & velić, i. (1978): lituolipora polymorpha n. gen., n. sp. (foraminiferida, lituolacea?) from the middle liassic of the outer dinarids in croatia and the establishment of a new family, lituoliporidae.– geol. vjesnik, 30, 73–93. hottinger, l. (1967): foraminifères imperforés du mesozoïque marocain.– notes et mémoires du service géologique, 209, 1–128. kaminski, m.a. (2000): the new and reinstated genera of agglutinated foraminifera published between 1986 and 1996.– in: hart, m.b., kaminski, m.a. & smart, c.w. (eds.): proc. 5th int. work shop agglutinated foraminifera, grzybowski foundation special publication, 7, 185–219. kaminski, m.a. (2004): the year 2000 classification of the agglutinated foraminifera.– in: bubík, m. & kaminski, m.a. (eds.): proc. 6th int. workshop agglutinated foraminifera, grzybowski founda tion special publication, 8, 237–255. loeblich, a.r., jr. & tappan, h. (1987): foraminiferal genera and their classification.– 2 volumes, 1–970, (van nostrand reinhold) new york. meriç, e., avşar, n., bergin, f. & barut, i.f. (2003): a note on three abnormal samples of benthic foraminifers from the dikili bay (turkey) in the northeastern aegean sea: peneroplis planatus (fichtel and moll), rosalina sp., and elphidium crispum (linne).–mineral res. explor. bull., 127, 1–14. mukhopadhyay, s.k. (2012): guembelitria (foraminifera) in the upper cretaceous-lower paleocene succession of the langpar formation, india and its paleoenvironmental implication.– journal of the geological society of india, 79/6, 627–651. doi: 10.1007/ s12594-012-0101-4. nikler, l. & sokač, b. (1968): biostratigraphy of the jurassic of velebit (croatia).– geol vjesnik, 21, 161–176. pelissié, t. & peybernès, b. (1982): étude micropaléontologique du jurassique moyen/supérieur du causse de limogne (quercy).– revue de micropaléontologie, 25/2, 111–132. radoičić, r. (1966): microfaciès du jurassique des dinarides externes de la yougoslavie.– geologia, 9, 5–378. ramalho, m.m. (1971): contribution à l´étude micropaléontologique et stratigraphique du jurassique supérieur et du crétacé inférieur des environs de lisbonne (portugal).– serv. geol. portugal mem., 19, 1–212. schlagintweit, f. & velić, i. (2011): new and poorly known middle jurassic larger benthic foraminifera from the karst dinarides of croatia.– geol. croat., 64/2, 81–99. doi: 10.4154/gc.2011.08 septfontaine, m. (1988) vers une classification évolutive des lituolidés (foraminifères) jurassiques en milieu de plate-forme carbonatée.– revue de paléobiologie vol. spec. 2 (benthos ´86), 229–256. smout, a.h. & sugden, w. (1962): new information on the foraminiferal genus pfenderina.– palaeontology, 4, 581–591. vecchio, e. & hottinger, l. (2007): agglutinated conical foraminifera from the lower-middle eocene of the trentinara formation (southern italy).– facies, 53/4, 509–533. doi: 10.1007/s10347007-0112-6 velić, i. (1977): jurassic and lower cretaceus assemblage-zones in mt. velika kapela, central croatia.– acta geol., 9, 15–37. velić, i. (2005): benthic foraminifera assemblages and stratigraphic subdivision of the middle jurassic in karst dinarides, adriatic carbonate platform.– in: velić, i., vlahović, i. & biondić, r. (eds.): 3rd croatian geological congress, opatija, 2005, abstracts book, croatian geological survey zagreb, 159–160. velić, i. (2007): stratigraphy and palaeobiogeography of mesozoic benthic foraminifera of the karst dinarides (se europe).– geol. croat., 60, 1–113. velić, i. & sokač, b. (1978): biostratigraphic analysis of the jurassic and lower cretaceous in wider region of ogulin (central croatia).– geol. vjesnik, 30, 309–337. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeography, palaeoclimatology, palaeoecology, 220/3–4, 333–360. doi.org/10.1016/j.palaeo.2005.01.011 manuscript received october 02, 2012 revised manuscript accepted november 30, 2012 available online february 28, 2013 gc 58-1.indb recent sediments of makirina cove (northern dalmatia, croatia): their origin viewed through a multidisciplinary approach marko šparica1, georg koch1, mirko belak1, slobodan miko1, martina šparica-miko1, damir viličić2, tadej dolenec3, stanislav bergant1, sonja lojen4, polona vreča4, matej dolenec3, nives ogrinc4 and haris ibrahimpašić1 1. introduction the markedly indented coastline of both mainland and islands along the eastern adriatic has formed numerous bays and coves, mostly representing restricted, shallow marine depositional environments within which recent (holocene) sediments accumulate. some of these sediments have been investigated from a specific viewpoint dealing with a particular problem. a number of papers on holocene sediments from ne adriatic sites have been published based on investigation or material of the göttingen working group (d. meischner). accordingly, investigations have been carried out dealing with sedimentology (fütterer, 1969; paul, 1970; meischner, 1972; ranke, 1974; fütterer & paul, geologia croatica 58/1 21–72 14 figs. 12 tabs. 9 pls. zagreb 2005 key words: recent sediments, geological setting, sedimentology, mineralogy, geochemistry, o and c stable isotopes, palynofacies, depositional environment, makirina cove, northern dalmatia, croatia. 1 institute of geology, sachsova 2, hr-10000 zagreb, croatia; e-mail: mksparica@igi.hr 2 university of zagreb, faculty of science, department of biology, rooseveltov trg 6, hr-10000 zagreb, croatia; e-mail: dvilici@biol.pmf.hr 3 university of ljubljana, faculty of natural sciences and technology, department of geology, aškerčeva 12, slo-1000 ljubljana, slovenia; e-mail: tadej.dolenec@ntfgeo.uni-lj.si 4 “jožef štefan” institute, department of environmental sciences, jamova 39, slo-1000 ljubljana, slovenia; e-mail: polona.vreca@ijs.si abstract makirina cove was formed by the holocene sea-level rise which caused a marine ingression into the depression formed within albian– cenomanian dolomites at approximately 4.5 ka b.p. at present, makirina cove represents an restricted, stressed, shallow-marine (<2 m) ecosystem characterized by varying seawater temperatures (0–35°c) as well as fluctuating salinities (up to 41‰) affected by seasonally enhanced evaporation, continuous freshwater supply through on-shore and submarine springs associated with the coastal karst area and surface run-off episodes. these environmental conditions have been conducive to high primary production of organic matter resulting in the formation of organic-rich deposits which contain up to 5 wt.% of organic carbon. up to the present times, 3.5 m of sediments have been deposited indicating a relatively high sedimentation rate estimated at 0.75 m/1.0 ka in the northern central part of the cove. the sediments are being deposited mostly as poorly sorted clayey–sandy silts. the distribution and concentration of most of the chemical elements is dependant on the mineralogical composition and granulometric features of the makirina sediments, which show values more or less similar to those from the central adriatic. accordingly, there is a positive correlation with al and k concentrations increasing off-shore and with the depth being associated with increasing concentrations of clay minerals within the clay fraction. the same holds true for concentrations of some trace elements, especially mo and se which is consistent with the distribution pattern of sulphides. selenium is preferentially enriched in authigenic pyrite and it is probably the major source of se in the makirina cove sediments. the concentrations of ca, mg and sr decrease off-shore and they are linked to the composition of the surrounding carbonate rocks. the saturation indices show that the water is supersaturated with respect to carbonates enabling the precipitation of authigenic amorphous or crystalline carbonate phases from the pore water in the upper segment of the sediment column. according to the oxygen isotopic (δ18o) composition, molluscs precipitated their carbonate shells mostly during warmer periods (may to november) at or near isotopic equilibrium with their ambient waters. the carbon isotopic δ13c composition of mollusc carbonate shells is environmentally affected due to oxidation and decomposition of organic matter as well as influxes of fresh water into the cove, indicating their formation out of the predicted isotopic equilibrium with atmospheric co2. palynological and organic carbon isotopic (δ13c) composition shows that the sedimentary organic matter (som) is 70–90% lipidand hydrogen-rich and on average 2/3 marine derived (mainly phytoplankton, bacteria and marine macrophytes) and 1/3 terrestrially derived (mainly woody tissue). the variations in composition of som have been noted as a function of the distance from the shore. the type and the preservation state of som and pyrite as well as the measurements of eh, ph, total alkalinity, dissolved inorganic carbon (dic) and the enrichment of redox-sensitive trace elements, indicate oxygen-depleted depositional conditions and that the sediment is highly reductive even in the uppermost segment at the sediment/water interface. according to the results obtained from the applied methods, the features of makirina sediments strongly reflect the given depositional conditions within this restricted, stressed, shallow-marine environment where these organic-rich sediments originate, and may therefore serve as a calibration standard in further investigations. 22 geologia croatica 58/1 1976), benthic foraminiferal dynamics (daniels 1971; meischner, 1971; paul, 1971) and ostracod assemblages (uffenorde, 1971, 1975), pollution problems (stirn et al., 1974), interstitial water composition (cescon et al., 1975), heavy metal composition (paul & meischner, 1976), vegetation development (beug, 1977), geochemistry and microbiology (golubić et al., 1977), and sea-level changes based on sedimentology, fossil biota and geochemistry (meischner, 1995). during the last two decades, investigations of recent sediments have intensified and have also included a number of sites from other regions of the eastern adriatic. the study of the recent sediments of the krka river estuary has yielded information on heavy metal distribution (prohić & juračić, 1984, 1989; prohić & kniewald, 1987), organic matter and sediments (jednačakbišćan & juračić, 1987), approach to pollution problems (pravdić & juračić, 1988), suspended matter and sediments (juračić & pravdić, 1991) and sedimentology (juračić & prohić, 1991). similarly, the papers dealing with the raša river estuary recent sediments have reported on pollution problems (juračić et al., 1992), particulates and trace metals (vdović & juračić, 1993; sondi et al., 1994) and sedimentology (sondi et al., 1995; bogner et al., 2003). the recent sediments of kaštela bay have been investigated in order to define heavy and trace metal distribution (bogner et al., 1998) and in pirovac bay selenium distribution (miko et al., 1998). the results of the study of the morinje bay sediments have included some consideration of kerogen precursor formation processes (koch et al., 2000) and pollution problems (koch et al., 2002). recent sediments of the croatian islands have also been a matter of scientific interest for quite a long time. for example, the study of the mljet lakes sediments has provided information on sedimentology (seibold & wiegert, 1960; juračić et al., 1998; govorčin et al., 2001), vegetation hystory (beug, 1961), sea-level, i.e. environmental changes based on diatoms and geochemistry (wunsam et al., 1999) and dynamics of benthic foraminiferal assemblages (vaniček et al., 2000; ćosović et al., 2002), whereas from the vrana lake of cres island the distribution of trace metals in the surface sediments has been reported (miko et al., 2003). in addition, the recent sediments of nin lagoon, karin bay and pirovac bay have been investigated from the balneological point of view being classified as healing mud, i.e. peloids with great potential in medical treatment (mandić et al., 1969; novak, 1981; oluić et al., 1984; miko et al., submitted). this overview of selected references and topics concerning the recent sediments from the eastern adriatic sites shows that investigations have been carried out in a particular way depending on the given objectives. taking into account these known facts, and the general idea that investigations based on a methodologically integrated concept may serve as a basis for solving all implied problems, a working group has been convened at the institute of geology, department of geology, zagreb, in order to conceptualise a project for further investigation of the recent sediments within the research project “basic geological map of the republic of croatia, scale 1:50.000”. consequently, the project “recent sediments of the coast and the islands of the republic of croatia” has been established in order to study the sediments, on the one hand, in all aspects by using the concept of a multidisciplinary approach and, on the other hand, to apply the results obtained from these investigations to a wide range of interests. this means that many types of standards have to be compiled within the calibration of the reference sites which can then be correlated with other sites, and to apply the actualistic principles while studying and interpreting various aspects of recent and fossil sedimentary bodies of similar origin. as all depositional environments are characterised by the complex interaction of biological, physical and chemical processes, any variation may then be interpreted in terms of environmental, i.e. ecological changes which have been caused by natural and/or anthropogenic influences, in recent sediments and natural influences in fossil sediments. therefore, the main objectives of this project are to: (1) define the origin of the sediments, especially regarding formation processes, (2) apply the results of the investigation into every potentially interesting field, (3) evaluate the economic value of the sediments, (4) estimate the degree of anthropogenic pollution, and (5) publish the obtained results as far as possible within the frame of the presented investigation objectives. the investigation of sediments of makirina cove, morinje bay and velike soline has recently been carried out in terms of the concept of a multidisciplinary approach, providing a better insight into the complexity of their origin. the results of this investigation have opened some new perspectives concerning the processes of formation of the sediments within these sensitive depositional environments. therefore, it is suggested that this multidisciplinary approach may well represent a methodological model for further research work on shallow marine sediments from other sites, both coastal and island, along the croatian eastern adriatic. in this paper we present the results of the investigation of the makirina cove sediments with regard to their origin. 2. geographical properties the basic geographical property of the sw part of the coastal area of šibenik, to which makirina cove belongs, is the markedly indented coast (fig. 1). makirina cove represents the sw prolongation of pirovac bay (fig. 2) with a n–s extension, approximately 1,250 m in length and 300 m in width. it is surrounded by moderately sloped ground of the makirina and gračina hills. along the shore line, a few periodic, low capacity on-shore springs and low capacity underwater 23šparica et al.: recent sediments of makirina cove (northern dalmatia, croatia)... springs occur. the water-wells in the quaternary deposits contain slightly brackish water. the sea depth of the southern part of the cove, where a periodical stream flows in, rarely exeeds 0.5 m, gradually increasing towards the ne up to 4.5 m (fig. 3). the bottom of the cove is mainly covered with vegetation, sporadically revealing silty and muddy ground (fig. 3). seagrass (cymadocea nodosa), algae (codium bursa), numerous lamellibranchs (laevicardium oblongum and others), gastropods (gourmya vulgata and others), crustaceans and foraminifera, indicate the rather favourable conditions for the development of the floral and faunal communities within this ecosystem. the climate is typical mediterranean. the winters are mild, rainy and windy, and the summers are warm and dry with a high insolation rate. according to the number of insolation hours (2572 h/y, measuring station šibenik), the area of šibenik belongs to the sunniest parts of the coastal adriatic. the mean value of annual temperature is 16°c; in january 6–8°c and in june 25– 26°c. the sea-water temperature ranges annually from 0–35°c. the salinity is variable, in places due to small capacity submarine springs it is brackish, and reaches values up to 41‰ during the summer. precipitation has two maximums; the amount during the winter is higher than during the spring. the mean value of the annual precipitation is 840 mm. the main winds are bura (north-eastern wind, mostly during winter), jugo (south wind) and maestral (landward breeze). 3. methods 3.1. field work on the basis of the principles of formation analysis, a geological map 1:10,000 of the region surrounding makirina cove was constructed and interpreted. the sediments of makirina cove were investigated by producing profiles which were located perpendicular to the longer axis of the cove (fig. 4). the distance between profiles was 24 m in the southern part and 50 m in the northern part. the distance between the probes was defined with a measuring strip. the topographic map 1:2,500 was fig. 1 index map. fig. 2 makirina cove. 24 geologia croatica 58/1 used for the construction of the probe network. each probe includes a description of the general conditions and measurements (sea depth, sea temperature on top and bottom, bottom features such as: silty, muddy, vegetation cover, etc.) as well as drilling sediments with a spiral borer to enable description of their features (colour, scent, granulometric composition, plasticity, etc.). in this manner, the sediments of the makirina cove were investigated with a total of 778 probes. for the purposes of the analytical research, an additional probe network was constructed for core samples (figs. 4 and 8). the samples were taken with a corer (diameter 5 cm, length 50 cm) from a depth of 1–3 m. 3.2. analytical methods 3.2.1. sedimentological analysis the granulometric composition of the sediments was defined using wet sieving and the laser granulometric method for the <63 μm fraction. grain size boundary fig. 3 sea bed map and sea depths. legend: 1) the bottom covered with vegetation; 2) sandy–muddy bottom, along the shore gravelly with outcropping rocks; 3) isobath; 4) sea depth; 5) partition wall. 25šparica et al.: recent sediments of makirina cove (northern dalmatia, croatia)... values were used according to the standard wentworth scale. within the 0.09–0.16 mm fraction, calcite was dissolved with cold 4% hcl. from the remainder, the light and heavy mineral fractions were separated using chbr3 (s.g. 2.89 g/cm3). microscopic slides were made from each part of the fraction. qualitative and quantitative analysis of the minerals was performed by polarisation microscope. 3.2.2. geochemical analysis 3.2.2.1. total content of major, minor and trace elements surficial sediment and sediment core samples were taken from 29 sites in the southern part of makirina cove (fig. 5). sediments were collected with hand-driven plexyglass core samplers (40 cm long and 3.5 cm internal diameter). the sediment samples and cores were airdried, then split into 5 cm long intervals and stored in fig. 4 probe network. legend: 1) marked profile line; 2) numbered sample. 26 geologia croatica 58/1 clean polyethylene bottles. only the top 5 cm were used for the purpose of this study. in the laboratory, the dried samples were desegregated and homogenised. fractions smaller than 1 mm were analysed. major (si, al, fe, ca, mg, na, k), minor (mn, ti, p) and trace elements (ag, au, ba, be, bi, sr, y, zr, v, cu, pb, zn, cd, as, hg, ir, sc, ta, ni, co, cr, cs, hf, mo, rb, sb, se, th, u, w, la, ce, nd, sm, eu, tb, yb, and lu) were determined by icp, inna and icp/ms. concentrations of be, ag, cd, bi, au, hg, ir, ta, and w were generally below the detection limit of the selected method (be – 2 ppm, ag – 0.4 ppm, cd – 0.5 ppm, bi – 5 ppm, au – ppb, hg – 1 ppm, ir – 5 ppb, ta – 1 ppm, w – 3 ppm). c and s were analysed separately with a leco analyser. analytical blanks were run with the samples, and a marine sediment reference standard mag–1 (us national bureau of standards), as well as our laboratory standards j1 and j2 (surficial sediment from the northern adriatic sea) were used to check the accuracy of the analytical procedure. geochemical analyses were carried out at the activation laboratories, ontario, canada. analytical precision and accuracy were better than ±3% for major elements, ±5% for ree, but between 5 and 9% for minor and remaining trace elements. this was indicated by results of duplicate measurement for 8 samples and the usgs mag–1 standard. 3.2.2.2. selenium speciation analysis the contents of se in surficial sediments of makirina cove were determined by hydride generation inductively coupled plasma atomic emission spectrometry. the surficial sediments (0–20 cm) and shallow core (0–30 cm) sediments were analyzed for se content by hydride generation icp atomic emission spectrometry after extraction of sediment se by three different dissolution techniques: 7 m hno3 digestion, aqua regia digestion and the acid mixture hf–hcl–hno3. the 7 m hno3 digestion could be used for selenium speciation (kuldvere, 1989; hall & pelchat, 1997). all reagents were of analytical reagent grade and deionized water was used throughout all dilutions. standard solutions containing 1000 mg seiv were obtained from merck and were also prepared by dissolving seo2 (merck) in water and acidifying with 5 mol l-1 hcl. the reducing agent sodium tetrahydroborate (1% solution) was prepared daily by dissolving solid compounds in a 0.1 mol l-1 solution of naoh and filtered (hall & pelchat, 1997). the use of hno 3 digestion of stream sediments has found application by some authors (kuldvere, 1989) for selenium speciation. namely, this procedure extracts both seiv and sevi into solution without reduction of sevi which is not reactive with sodium tetrahydroborate, and therefore it is possible to determine the quantities of seiv and total se (by pre-reduction with 5 m hcl or by aqua regia digestion or by the acid mixture hf–hcl–hno3). 3.2.2.3. pore water geochemistry sediment cores were collected manually at site 3 with a plexiglas tube, immediately transferred to the laboratory and cut into 2–4 cm thick sections in a glove bag filled with nitrogen. redox potential (eh) was measured immediately after coring by inserting an electrode into the core through 1 cm side openings in the tube, covered with plastic adhesive tape. pore water was extracted under a pressure of 0.4 mpa through a 0.45 µm membrane filter. the ph and total alkalinity were determined immediately in the glove bag. subsequent samples were taken for total alkalinity, metal cations, nutrient (nh4 +, no3 -, so4 2-, s2-, po4 3-) and δ13c–dic analyses. an incubation experiment was performed at sites 3 fig. 5 sampling points. 27šparica et al.: recent sediments of makirina cove (northern dalmatia, croatia)... and 5 to determine the in situ benthic fluxes of nutrients at the sediment/water interface. plexiglas chambers with a diameter of 210 mm were inserted about 35 cm deep into the sediment. the height of the water layer in the chambers was about 15 cm, and the height of the water layer above the cover was more than 5 cm even at low tide. the water in the chamber was gently stirred manually a few times per day. water samples were taken using plastic syringes approximately 5 cm above the bottom at regular time intervals over a period of 10 days. the volume of the sample taken was compensated through a compensation valve. ph, salinity, total alkalinity, δ13c–dic, and concentrations of the main nutrients, as well as ca2+, mg2+, fetot and mntot were determined; all concentrations were corrected for the compensating dilution. for methane isotopic analysis, sediment from the depth segment 0–15 cm was incubated in the dark as a slurry (sediment+seawater in 1:1 ratio) in diffusion bottles kept upside-down at room temperature. headspace ch4 was analysed for δ13c. the ph of the extracted pore water was measured with a combined ph electrode. salinity was determined refractometrically (atago, japan). total alkalinity (±2%) was determined by the gran titration method. the concentration of dic was calculated from the ph and total alkalinity as described by millero (1995). nitrate, ammonia, and sulphide concentrations were determined using colorimetric procedures described by grasshoff et al. (1983). sulphate was determined turbidimetrically (tabatabai, 1974). the precision of all anion analyses was better than ±2%. concentrations of ca2+ (±2%), mg2+ (±1%) and fetot (±3%) in pore water were measured by flame aas (varian aa5). the stable isotopic composition of dic and ch4 was determined by mass spectrometry. the water sample for isotopic analysis was injected into an evacuated container with 100% h3po4 and the co2 released was analysed using a europa 20–20 stable isotope analyser with an anca tg trace gas separation module. the isotopic composition of ch4 was determined after oxidation on cuo at 800°c on the same apparatus. the precision of the analysis was better than ±0.2‰. porosity (φ) was calculated from the weight loss of the sediment dried overnight at 110°c using the relationship: φ = (mw /1.0) / [(ms / 2.5) + (mw /1.0)] , where mw is the weight loss upon drying, ms is the weight of dry sediment, and 1.0 and 2.5 are the densities (g/cm3) of water and sediment, respectively (johnson et al., 1982). 3.2.3. mineralogy by x-ray powder diffraction the mineralogy of surficial sediment samples and mollusc shells was determined by x-ray powder diffractometry using a philips pw 3710 diffractometer and cu kα radiation. powder samples were scanned at the rate of 2° per minute, over the range of 24–60°. the results were stored on a pc computer and analysed with pc– apd diffraction software. 3.2.4. isotope analyses 3.2.4.1. biogenic carbonates live specimens of laevicardium oblongum, nuculana fragilis, monodonta turbinata, columbella rustica and gourmya vulgata were collected from makirina cove, pirovac bay and the coastal part of the murter sea. specimens were transported to the laboratory in seawater, immediately rinsed in tap water and killed by freezing at -18°c. the specimens remained frozen until shucked. shells were scrubbed clean with a plastic scouring pad then air dried, and stored at room temperature until analysed. prior to analysis of isotopic composition, powdered samples of the investigated mollusc shells were roasted at 380°c for 1 hour to volatise organic matter. thereupon the samples were reacted in an acid bath with excess 100% h3po4 at 25°c (mccrea, 1950). co2 gas released during acid treatment was cryogenically cleaned and analysed for o and c isotope composition on a varian–mat 250 mass spectrometer. the δ18o and δ13c values were normalized by assuming δ18o and δ13c values of -2.44‰ and +2.48‰ for iaea–co–1 standard on the vpdb scale. the analytical precision based on multiple analysis of an internal laboratory standard was ±0.01% (1σ) for δ18o and δ13c. the overall analytical replication of the carbonate carbon isotopic data was ±0.1‰. 3.2.4.2. organic matter (sedimentary organic matter, terrestrial plants, aquatic plants, algae) carbon isotopic composition of sedimentary organic matter, terrestrial plants, algae, and aquatic plants were measured in the carbonate-free samples on a europa 20–20 stable isotope analyser (europa scientific ltd.), with anca–nt preparation module for on line combustion of bulk solid samples and chromatographic separation of the gasses. for preparation of total organic carbon, the powdered sediment, terrestrial as well as aquatic plant and algae samples were treated with 3m hydrochloric acid at 50°c to remove the carbonates. upon cessation of co2 evolution, excess acid was removed by repeated washing (three to four times) with double distilled water, until the ph was neutral. after the final decantation of water, the carbonate-free residues, mostly composed of organic matter, were oven-dried at 50°c. organic carbon isotope ratios were measured in a europa 20–20 stable isotope analyser (as above). organic carbon isotope values were calibrated using the iaea–ch–7 standard with a δ13c value of -31.8‰ on the pdb scale. the results are reported in the conventional delta notation as ‰ deviation from the pdb standard. the analytical precision for organic carbon based on multiple analysis of an internal laboratory standard was δ13c ±0.01‰ (1σ). overall analytical reproducibility of the organic carbon isotopic data was ±0.1‰. 28 geologia croatica 58/1 3.2.4.3. seawater to define the o and c isotopic composition of ambient seawater and the isotopic composition of ambient seawater dic, seawater was collected monthly from june 1999 until september 1999. to preserve the water samples and to prevent the possibility of continuing biological activity a few mg of hgcl2 powder was added to each water sample selected for δ13c analysis. water samples were stored in a refrigerator until analysed for δ18o by the procedure outlined in epstein & mayeda (1953) in which δ18o is measured in co2 that has been equilibrated with the water to be analysed at a defined temperature for a number of hours. however, because of the salinity, equilibration was necessary for 48 h at 25°c prior to extracting the co2. the “salt correction” equation for 18o was then applied after sofer & gat (1975). stable isotopic analyses were carried out on the varian mat–250 mass spectrometer. for δ13c analyses of dic the isotopic composition of co2 liberated from 5 ml of water after acidification was determined using a europa 20–20 anca–tg mass spectrometer. the results are reported in the conventional delta notation as ‰ deviation from the vsmow for δ18o and vpdb standard for δ13c. overall analytical reproducibility of the isotopic data was better than ±0.15‰ for seawater oxygen, and ±0.1‰ for dissolved inorganic carbon. 3.2.5. palynofacies core-samples were taken approximately 10 cm below the top of the sediments along the transect i (fig. 4). samples were dried and 50 g of each was used for palynological processing. the carbonates were dissolved with hcl (10%) and the silicates with hf (40%). heavy liquid of zncl (2.1 kg/l) was used to separate the organic matter from the inorganic components. no further treatment (sieving, oxidation) of the organic residue has been attemped in order to analyse the organic matter as a whole and to avoid alteration of organic matter preservation due to processing. palynological slides were made always using the same amount of organic residue of each sample and glycerin gelatin as the mounting medium. microscopic examination of the palynodebris was carried out in both transmitted and incident blue light. qualitative analysis of the palynological organic matter (pom) was conducted using the diagnostic criteria of palynomorphs and palynodebris. microscopic examination in incident blue light was applied to identify hydrogen-rich and lipid-rich structured, structureless and amorphous organic matter, and to assess their relative fluorescence intensity. quantitative analysis is based on both the relative estimation of structureless and amorphous organic matter, and calculated absolute frequencies of both land and marine derived structured categories per palynological slide. 4. results and discussion 4.1. geological setting of makirina cove 4.1.1. lithostratigraphy the geological map (fig. 6) shows that makirina cove is mostly surrounded by cretaceous carbonate successions. the area of ivinj draga is covered with a relatively thin layer of quaternary clastic deposits. according to the lithological features and microfossil assemblages, the following informal lithostratigraphic units may be discerned: a) ivinj dolomites; b) makirina limestones and dolomites; c) kamena “rudist limestones”, and d) ivinj draga deluvial deposits. a) ivinj dolomites (albian–cenomanian) – extend over the ivinj draga area, southern slopes of makirina and the northern slopes of the kamena hills. towards the nw, the unit dips beneath the sea in pirovac bay. the sw contact with unit c is reversed, whereas towards the ne it passes continuously into unit b. unit a consists of medium grained late-diagenetic dolosparites and dolomicrosparites with relics of primary micrites. they are mostly exposed as well-bedded layers between 10– 50 cm thick, sporadically as laminated variations. the shore of makirina cove is built up of diagenetic dolomitic breccia (fig. 6 – geological column; for more information on diagenetic breccia in contemporaneous deposits see vlahović et al., 2002). within the succession of unit a, lenses and intercalations of dolomitic micrites, dolosparites, dolomicrosparites and dolomitic breccia occur. rare occurrences of partly recrystallized fossiliferous micrites were also identified. the thickness of the unit a is 250 m. the dolomitisation processes have destroyed the fossil content, thus the stratigraphic position of unit a is approximate according to similar successions in dalmatia and the overlying unit b. b) makirina limestones and dolomites (cenomanian– turonian) – unit b conformably overlies unit a on the northern slopes of the makirina and čelo hills (fig. 6). it is characterized by the vertical alteration and interfingering of limestones and dolomites. limestones are well-bedded (in layers 10–30 cm thick) and substantially recrystallized. they have been identified as micrites, biomicrites and biopelmicrudites. thin layered limestones (5–15 cm thick) occur along the boundary with unit a and throughout the unit as intercalations and lenses. crystallinic peletoid biomicrudites were sporadically found. the dolomites belong to the group of late diagenetic dolosparites with a varying percentage of dolomite and limestone relics indicating the degree of dolomitisation. the limestones of unit b contain specifically indeterminable rudists (radiolites sp.) and lamellibranchs (chondrodonta sp.). the microfossil assemblage contains numerous benthic foraminifera (e.g. chrysalidina gradata, broeckina (p.) balcanica), aeolisaccus kotori 29šparica et al.: recent sediments of makirina cove (northern dalmatia, croatia)... and thaumatoporella parvovesiculifera. most of unit b was deposited in quiet, periodically lagoonal settings, whereas the grainy (crystallinic) limestones are related to shallow marine, agitated environments. the thickness of unit b is 350 m. c) kamena “rudist limestones” (early senonian) – unit c continuously succeeds unit b on the sw part of kamena hill (fig. 6). unit c is represented by well-bedded, strongly karstified and partly or completely recrystallized bioclastic limestones. the thickness of the layers is 20–150 cm. the limestones were mostly identified as varieties of biosparites and biomicrites. sporadically, intercalations of dolomitic limestones occur. the limestones of unit c contain a rich fossil assemblage consisting mainly of rudists and numerous benthic foraminifera (including pseudocyclammina sphaeroidea, scandonea samnitica and murgella lata). they were deposited in quiet to agitated, shallow marine settings. d) ivinj draga deluvial deposits (quaternary) – these deposits originated due to erosion of older sediments of the area surrounding ivinj draga (fig. 6). unit d consists of silty clay mixed with gravel. 4.1.2. tectonics the structure and orientation of the area under consideration corresponds to the structure of the region of northern dalmatia, characterized by folds with “dinaric” vergences (nw–se). the folds are mostly elongated, often overturned. the faults are longitudinal, mostly reverse. these structures were formed during the pyrenean tectonic phase, and they are disturbed by neotectonic movements resulting in transversal and diagonal, vertical faults of n–s and ne–sw extension. in the wider area of makirina cove, the most striking structure is the overturned and tectonized ivinj anticline, the core of which is built up of unit a. the ne part of this structure is represented by unit b. the sw part of this structure is isoclinally folded and disturbed fig. 6 geological map, geological column, geological profile, lithostratigraphic units and lithology. legend: 1) deluvial deposits ivinj draga; 2) kamena “rudist limestones”; 3) makirina limestones and dolomites; 4) ivinj dolomites; 5) clastic sediments; 6) bedded limestones; 7) detrital limestones; 8) bioclastic limestones); 9) dolomite; 10) dolomitic breccia; 11) microfauna; 12) rudists; 13) conformable boundary; 14) isohypse; 15) fault; 16) reverse fault; 17) strike and dip of bed; 18) overturned bed; 19) profile line a–b; 20) periodic surface waterway; 21) submarine spring; 22) well. 30 geologia croatica 58/1 with longitudinal reverse faults (fig. 6 – profile a–b). along these reverse faults, unit a has been tangentially moved onto the unit c and the latter one (peninsula obinuš v.) onto the unit b. the structure is disturbed with vertical faults. 4.2. the sediments of makirina cove recent sediments of makirina cove are being accumulated on a albian–cenomanian dolomite basement 1200 m in length and 280–300 m in width. the gradual increase of sediment thickness (0–>3 m) from the coast towards the central part of the cove, especially along the longer axis, gives an appearance of the sediment body in a form of an elongated lense (fig. 7). the beginning of the transgression into the cove of makirina is related to global sea-level rise, rather than epirogenetic movements. in this case, we have defined the entrance of pirovac bay into makirina cove at 4.5 m isobath (fig. 4). on the basis of the sea depth, sediment thickness and the estimation of the sea-level rise during the holocene for the area of north dalmatia (šegota, 1982; šegota & filipčić, 1991), it is concluded that 4600 y b.p. the sea level was 6.6 m lower than at present. therefore, the 6.6 m isobath of that period was within pirovac bay, meaning that makirina was part of the land, being inundated later. the considerations on sea-level rise of makirina cove are in accordance with other sites of the adriatic sea as reported from istria (meischner, 1995), gargano subaqueous delta (cattaneo et al., 2003), lakes of mljet island (wunsam et al., 1999) and along the eastern adriatic encountering several submerged speleothems (surić et al., 2005). it is noteworthy to quote a historical fact considering the sea-level rise of makirina cove. at the end of the 13th century (1295), a salt-work of the šibenik diocese existed in the southern part of the cove. the top of the partition-wall of the cove (fig. 3) is at present some 30 cm below the sea level, and it was certainly a functional part of a middle ages salt-work. within the space of the salt-work of that period, the sea level is at present 0.10 m (near shore) to 0.30 m (partition-wall) higher, and the thickness of the sediments is 0.75 m. according to these data, in the last 700 years the sea level has risen approximately 1 m, and during that period some 0.75 m of sediments have been deposited. 4.2.1. sedimentological features of makirina cove sediments the colour of the sediments varies from gray, grayish brown, dark gray to black. the predominant colour is dark gray. over the whole surface down to 0.5 m depth the sediments are mostly black. along the shore to 0.5 m depth the sediments occur in a liquid state. otherwise, they contain 56–61% moisture and their plasticity is rather pronounced. in the ne, deeper part of the cove, the sediments gradually pass into clayey, sporadically sandy–gravelly layer with fine faunal debris. in different horizons of the sedimentary column, metre-sized lumachele lenses built up of mollusc shells (fig. 8) sporadically occur. the granulometric composition shows that most of the sediments in the cove are represented by poorly sorted (so>2.0) clayey–sand and sandy silt (table 1). along the shore and on the bottom, various debris, gravel and clay occur. towards pirovac bay, the sediments consist of sandy silt mixed with gravel and clay (fig. 8, profile 10). in general, the sediments are characterized by silt fraction (mean value 51%), sand fraction (predominantly fine-grained sandy subfraction, mean value 31%) and clay fraction (mean value 14%). the content of the gravel fraction is very low, and it only occurs in some samples as fragments of mollusc shells. the mean value of the grains of all samples is 0.04 mm. the sorting coefficient, which was estimated by use of the quartile method, shows a very low degree of sorting. granulometric analysis of the upper 10 cm of the sediments revealed that sandy silts prevail, which pass towards the shore into gravelly–sandy silt. the mean values of the fractions are: silt 58%, sand 27%, clay 8% and gravel 7%. while the fractions of silt, sand and clay are relatively constant, the fraction of gravel reaches values up to 22% along the shore (vreča et al., 1999). in the mineral composition of the sediments, noncarbonate minerals (mean value 61%) predominate over carbonate minerals (mean value 39%) down to 35 cm depth (table 2). within the group of non-carbonate minerals, clay minerals prevail (36%), followed by quartz (22%), halite (3%), pyrite and marcasite (2%). the association of minerals is dominated by muscovite, and followed by illite and other clay minerals with a common illite/ montmorillonite type of structure (mean value 27%) (table 2). the content of clay minerals with a common chlorite/montmorillonite type of structure is low. the abundance of clay minerals is highest in the central part of the cove, decreasing towards the shore. their abundance increases with the depth. the content of quartz is higher towards the shore, whereas in the central part of the cove it is considerably lower. the amount of halite and travertine decreases towards the shore. the highest concentrations of authigenic pyrite and marcasite occur in the central part of the cove, decreasing towards the shore. within an anaerobic environment with sulphate reduction, the released sulphur from pore waters enables the formation of authigenic sulphides (appelo & postma, 1994). this process is encouraged by sulphate reducing microorganisms. among the carbonate minerals, dolomite and amorphous calcite predominate (mean value 30%). the remainder (9%) consists of travertine and authigenic minerals, i.e. crystallized calcite and aragonite. their origin is, linked to saturation of pore waters in the sediments: saturation indices si > o are favourable for formation of calcite and aragonite. the content of dolomite 31šparica et al.: recent sediments of makirina cove (northern dalmatia, croatia)... and calcite near the shore is considerably higher (54%) compared to gradually decreasing values towards the central part of the cove. the same trend is related to depth. the highest concentration of aragonite is in the central part of the cove, gradually decreasing towards the shore (vreča et al., 1999). the sediments were dried at 107°c, revealing 16– 21% of organic and 79–86% of inorganic matter. dilute hcl dissolved 32–47% of inorganic matter of which 33–50% represents the insoluble residue. within the 0.09–0.16 mm fraction of insoluble residue, the composition of the light and heavy mineral fraction was identified (table 3). the light mineral fraction contains quartz, feldspars and rare fragments of chert and quartzite. quartz predominates with 63% (mean value). the grains are mostly semi-rounded of an irregular shape. the feldspars occur regularly in all samples (mean value 32%). the grains of feldspars are mostly semi-rounded and allotriomorphic, but weakly rounded, hypidiomorphic grains fig. 7 isopach map. legend: 1) isopachs of sediments thickness; 2) thickness of sediments of 0.0– 1.0 m; 3) thickness of sediments of 1.0–2.0 m; 4) thickness of sediments of 2.0–3.0 m; 5) thickness of sediments more than 3.0 m. 32 geologia croatica 58/1 fig. 8 geological profiles. legend: 1) clayey–sandy silt; 2) clay; 3) silt; 4) sand; 5) gravel; 6) lumachelle, lamellibranchs, gastropods; 7) probes with measurements of sediment thickness; 8) probes with measurements of sediment thickness and description of sediments; 9) sample. 3' 10' 10' t. 3' in r i \j l o~ i i """'-'.0---': 0"':"" : . -~~-i~~~ ~~ep:~~ 16 i i i i .. 234· i 10 (m) 0 2 3 4 5 6 7 234· 3 .. (in~ _ 1 14 _2 _3 _4 _5 _6 270· .. (in) 1 o i i ~: . 10 ! ---l...,,~ 4 7 r--i~ e--_v v....-2 3 4 5 '~v --xv' o 25 50 100 150 200 m ,"-------',----'-, -----"-, ------'-, ---------", 270· xv .. (in~ i",,1-1 1-2 1-3 33šparica et al.: recent sediments of makirina cove (northern dalmatia, croatia)... also occur. plagioclase is frequent, whereas k-feldspars are subordinate. the content of the heavy mineral fraction is approximately the same in all samples and varies between 3–15%: opâque minerals are estimated at 30% (mean value), whereas transculent heavy minerals at 70%. garnet is the most frequent transculent heavy mineral (mean value 30.4%). the grains are irregular, sample gravel sand silt clay sediment granulometric parametres % md so 1/2 3 27 55 15 clayey–sandy silt 0.03 3.0 2/7 7 43 50 sandy silt 0.07 2.2 2/9 11 59 30 clayey–sandy silt 0.01 5.3 2/11 18 57 25 clayey–sandy silt 0.02 5.1 3/14 62 38 clayey silt 0.01 2.9 3/16 13 65 22 clayey–sandy silt 0.01 3.6 3/18 4 28 63 5 sandy silt 0.10 4.0 4/18a 70 30 silty sand 0.08 1.5 4/22 3 27 59 11 clayey–sandy silt 0.03 3.5 5/28 40 51 9 sandy silt 0.05 2.4 6/32 5 20 60 15 clayey–sandy silt 0.03 2.9 6/34 6 35 47 12 clayey–sandy silt 0.04 3.0 7/38 17 33 42 8 gravely–sandy silt 0.06 6.9 7/39 4 41 45 10 sandy silt 0.05 3.7 8/44 7 30 52 11 clayey–sandy silt 0.05 3.5 8/46 3 32 52 13 clayey–sandy silt 0.04 3.3 9/50 6 27 52 15 clayey–sandy silt 0.03 4.2 10/53 8 40 41 11 clayey–sandy silt 0.06 3.3 10/55 7 50 31 12 clayey–silty sand 0.09 4.6 table 1 granulometric composition of the sediment. sample depth m/i+rx klo+rx2 qua. hal. arag. cal. d+k trav. pyr., marc. cm % % % % % % % % % m3/3-a 0-5 27 18 10 6 2 5 27 3 2 m3/3-b 5-10 30 7 15 8 4 7 25 3 m3/3-c 10-15 23 8 16 6 3 10 29 3 3 m3/3-d 15-20 27 12 11 6 3 3 37 2 m3/3-e 20-25 35 9 14 6 4 3 25 1 3 m5/3-a 0-5 23 6 21 2 5 42 1 m5/3-b 5-10 21 6 21 2 6 42 2 m5/3-c 10-15 27 6 25 3 6 31 2 m5/3-d 15-20 27 3 23 3 5 35 2 3 m5/3-e 20-25 24 6 21 4 3 4 32 3 3 m5/3-f 25-30 30 9 24 4 2 4 19 4 2 m5/3-g 30-35 44 14 19 6 3 10 4 2 m7/2-a 0-5 12 3 11 6 13 54 1 m7/2-b 5-10 27 14 21 15 21 2 m7/2-c 10-15 17 8 23 8 44 1 m7/2-d 15-20 17 11 22 2 9 38 1 m7/2-e 20-25 34 8 30 5 21 1 m7/2-f 25-30 34 16 24 11 14 1 table 2 mineral composition of the sediments from the probes m3/3, m5/3 i 7/2. legend: m/i+rx1 – muscovite/illite + clay minerals with a common illite/montmorillonite type of structure; klo+rx2 – chlorite + clay minerals with a common chlorite/montmorillonite type of structure; qua. – quartz; hal. – halite; arag. – aragonite; cal. – calcite; d+k – dolomite + amorphous calcite; trav. – travertine; pyr. – pyrite; marc. – marcasite. 34 geologia croatica 58/1 weakly rounded and often broken. sometimes, they are semi-rounded, idiomorphic and “fresh” in appearance. colourless and brown garnets are most frequent, but rosy variations were also identified (plate i, figs. 9, 10, 13 and 16). the amphibole group of minerals accounts for 24.5% (mean value). the grains mostly appear as broken, semi-angular prismatic forms (plate i, fig. 7). although glaucophane is represented in very low concentrations, its presence in all samples is characteristic (plate i, figs. 5 and 6). pyroxene concentrations within the transculent heavy mineral fraction are estimated at 20.8% (mean value). the grains are semiangular to angular, prismatic in shape, often irregularly broken (plate i, fig. 8). epidote and zoisite are present in all samples. zircon represents 8% (mean value) of the fraction. the grains are variably shaped, ranging from angular to rounded forms (plate i, figs. 11, 15, 17 and 18). the composition of the light and heavy mineral fractions indicate that their source is related to metamorphic rocks and also to extrusive rocks due to the influence of explosive volcanic eruptions. the morphometric features of the resistant minerals show that some have been transported for long distances and resedimented in several cycles. one of the problems related to the origin of the sediments of makirina cove is the interpretation of the source and the transportation mechanism of the light and heavy mineral fractions which are represented in a relatively high concentration. it has already been documented that the cretaceous successions of the area surrounding makirina do not contain light and heavy mineral fractions. on the other hand, a similar mineralogical assemblage has been identified in dalmatia in eocene flysch and quaternary deposits (šparica et al., 1995). however, the closest exposures of eocene flysch are situated some 6 km ne of makirina and they are physically separated from makirina by the nw–se extension of the structures. the same holds true for the quaternary deposits, though located in the vicinity of makirina. the mineralogical assemblage contains grains of different specific weights, indicating the absence of separation of the grains during the transport. this implies that the wind probably played a subordinate role in their transportation, but also the absence of selective settlement within the depositional area according to their hydrodynamic features. nevertheless, it is clear that most of the light and heavy mineral fractions originated through erosion of eocene flysch deposits. some influence of most probably holocene explosive volcanic activity is exemplified by the presence of volcanic glass characteristically absent in eocene flysch deposits. 4.2.2. selenium speciation in sediments since no marine sediments with certified contents of selenium were available, analysis of the geologic reference soil material gxr–2 (usgs) was performed. the certified se content of this material (gladney & burns, 1984) is 0.57±0.17 mg kg-1 and the following results were obtained: 0.35 mg kg-1 se by 7 mol hno3 digestion, 0.47 mg kg-1 se by hot aqua regia digestion and 0.51 mg kg-1 se by closed microwave hf–hcl– hno3 digestion. the results of selenium analysis by all three digestions in the marine sediments from makirina cove are presented in table 4. the amount of selenium extracted with 7 mol hno3 was the lowest as expected, and is approximately 50% of the selenium obtained by closed microwave hf–hcl–hno3 digestion, ranging from 0.19 to sample l. m.f. (100%) h. m.f. h. m.f. (100%) translucent minerals (100%) q f r v.g. % op translc. ep am py g cr t zr ru ti ap gl 1/2 61 34 5 3 28 72 15 25 24 28 1 1 3 1 1 1 2 2/7 65 32 3 3 36 64 9 22 20 30 1 11 1 1 1 1 2/11 68 24 8 3 35 65 8 26 16 36 1 10 2 1 1 3/14 69 27 4 + 8 28 72 12 20 20 34 1 9 1 1 2 1 3/16 65 31 4 + 7 30 70 11 21 23 32 1 1 8 1 1 1 1 4/18a 62 33 5 15 25 75 8 30 26 27 1 1 8 2 1 1 5/26 60 37 3 + 4 28 72 7 31 14 35 1 9 1 2 1 5/30 67 29 4 + 7 37 63 9 25 26 28 1 1 6 2 1 1 1 7/39 55 36 9 6 25 75 12 23 18 29 1 1 9 2 5 1 8/44 59 35 6 + 7 27 73 11 21 20 31 2 2 8 2 4 1 8/46 58 35 7 + 7 24 76 14 23 16 30 2 8 1 1 5 2 10/55 64 31 5 5 42 58 8 28 27 25 1 6 3 1 1 1 table 3 mineral composition of the light and heavy mineral fractions of the insoluble residue. legend: l. m.f. – light mineral fraction; q – quartz; f – feldspar; r – rock particles; v.g. – volcanic glass; h. m.f. – heavy mineral fraction; op – opâque minerals; translc. min. translucent minerals; ep – epidote; am – amphibole; py – pyroxene; g – garnet; ti – titanite; cr – chromspinel; t – tourmaline; zr – zircon; ru – rutile; ap – apatite; gl – glaucophane. 35šparica et al.: recent sediments of makirina cove (northern dalmatia, croatia)... 0.31 mg kg-1. the hot aqua regia digestion gave only slightly higher amounts of selenium in the range from 0.27 to 0.35 mg kg-1. the closed microwave hf– hcl–hno3 digestion gave approximately 40% higher se contents than the hot aqua regia digestion, ranging from 0.42 to 0.76 mg kg-1 (miko et al., 1998). selenium bioavailability from sediments is a longstanding impediment to determining se effects in ecosystems, since it is an essential trace element, which is toxic if present in excessive concentrations. in natural systems, it exists as selenate (seo4 2-), selenite (seo3 2), and organic and inorganic forms of selenide (se2-) (cutter & bruland, 1984). selenium is preferentially enriched in authigenic pyrite (mercone et al., 1999) and this is probably the major source of se in the makarina cove sediments. the aim of the various acid extractions was to evaluate the se bioavailability of the sediments. some experimental and field observations showed significant se uptake via ingestion implying that particulate organo-se in diatoms exposed to selenite was assimilated with >80% efficiency by a variety of bivalves (wang et al., 1996), and that elemental se precipitated in sediments by microbial dissimilatory reduction was less bioavailable. the bioavailability of se in makirina cove sediments based on the concentration difference of se extracted with 7 mol hno3 and total se (hf–hcl–hno3) implies a range of 40–60%. sulphate-reducing bacteria are capable of reducing selenate to selenide (zehr & oremland, 1987). the importance of the oxic-boundary in organic-rich sediments for se mobility has been stressed by mercone et al. (1999) and crusius & thomson (2003), who found that the effect was similar to the reduction mechanisms that cause enrichment of v and u from bottom waters to anoxic sediments. 4.2.3. geochemical characteristics of the surficial sediment the results of the geochemical characterisation of the 29 surficial sediment samples with mean, minimum and maximum values are given in table 5. the regional distribution of major, minor and trace elements in the makirina cove as indicated by the total analyses of surficial sediments are shown in plates ii–v. geochemical data indicate that the concentrations of the majority of trace elements are similar to those reported for argillaceous sediments and shales. some of them, including ni, co, as, cr, zn, sc, and v also exhibit similar values to the surficial sediments from the central adriatic (vreča et al., 1999), while the concentrations of others (ba, mo, cu, pb, th, u, la and zr) are higher. the distribution of major elements and their relative abundances are attributed to the mineralogical compositions of sediments. elevated sio2 contents imply the presence of relatively high percentages of quartz in the sediments. al2o3 and k2o concentrations suggest the clay minerals to be the most important factor controlling the distribution of al and k. k2o contents may also reflect a close association with the feldspars. cao, sr and, to some extent, mgo concentrations usually follow the carbonate content (calcite, aragonite and dolomite). na2o contents are probably due to the presence of feldspars and salt and are somewhat modified by the influence of the fresh water inflow through small sources along the coast. iron is principally associated with the silt–clay fraction and shows a similar distribution pattern to k and al. occurrences of iron sulphides in small cores indicate reducing conditions. this is also evident from h2s development during the summer. the relatively high organic content (from 2.93 to 7.17%) of the sediment most probably suggests that the iron sulphides are the product of the oxidation of organic matter by microbial mediated sulphate reduction (stumm & morgan, 1996). trace metal distribution is also roughly controlled by the mineralogical composition of the sediment, although post-depositional processes may have modified the initial trace element content at the time of sedimentation. our results showed that the surficial sediment of the makirina cove is relatively unaffected by pollution. anthropogenic contamination was observed in the southern part of the cove in the vicinity of the road kapela–tisno. the elevated concentrations of cu, pb, zn and ni in this relatively very limited area could be attributed to the traffic circulation and agricultural activity. higher concentrations of cu along the eastern coast of the cove also reflect the anthropogenic component of cu. the elevated values of this element extend away from the coast where there are fresh water inputs of cu to the marine environment, due to the agricultural activities in this area. the geographical distribution of trace elements also reflects the differences in redox conditions in the cove. elevated values of certain trace elements such as v, zn, cu, ni, pb, as, cs, br, mo, sb, sc, rb, th and v in sample p1 p2 p3 p4 p5 1 2 3 4 5 6 7 8 7 mol hno3 0.30 0.30 0.31 0.27 0.30 0.19 0.27 0.24 0.19 0.24 0.26 0.20 0.29 aqua regia 0.34 0.34 0.35 0.34 0.36 0.35 0.29 0.32 0.28 0.28 0.32 0.28 nd hf–hcl–hno3 0.76 0.56 0.56 0.46 0.58 nd 0.46 0.46 0.47 0.48 0.51 0.42 0.46 table 4 results for se (mg/kg) in sediment core samples (p) and in surface samples (m) by 7 mol hno3 digestion, hot aqua regia and closed microwave hf–hcl–hno3 digestion. 36 geologia croatica 58/1 the northern part of the cove most probably reflect their close association with clay mineralogy, (high al2o3 and k2o content) and more reducing conditions (high feo content). the more characteristic feature of this area is highly elevated concentration of mo (up to 47 ppm). although these may be attributed to the use of phosphate fertilisers, they still remain a puzzle. however, mo is also best known for its enrichment in anoxic or organic-rich sediments. within a given anoxic environment, mo tends to be enriched in the centres or most h2s-rich portion of the area (crusius et al., 1996). 4.2.4. organic-matter isotope geochemistry the δ13c of terrestrial plants (plate vi) in the area surrounding pirovac bay and makirina cove revealed values mostly in the range between -23.34 to -30.48‰ (table 6, fig. 9). the only exception is camphorosoma monospeliacea with δ13c in the range from -12.04 to -13.22‰. codium bursa, which is a very common alga in the cove, showed δ13c values ranging from -17.14 to -17.88‰. in contrast, the seagrass cymadocea nodosa, which also covers the greater part of the bottom in the cove, is considerably enriched in 13c, exhibiting δ13c values between -7.36 and -8.24‰. the δ13c composition of marine plankton and benthic animals as well as macrofauna was not directly measured. however, the δ13c of marine plankton and most of the marine organisms in the bay seems to exhibit similar values as were measured for plankton and other marine organisms in the north-western adriatic, i.e. -21.8 to -22.9‰ (vreča, 1998). mass-spectrometric analyses of organic carbon in surficial sediment in makirina cove (table 7, fig. 10) revealed high values (between -13.10 to -19.87‰) in the central and northern part of the cove and somewhat lower values (between -17.32 to -24.89‰) in the southern and coastal part affected by allochthonous input. the relative contribution of marine and terrestrial organic matter to sediment may be evaluated from δ13c measurement if the isotopic composition of the two end members are known and are different. due to the considerable variability of carbon isotopic composition in marine derived organic carbon end members (δ13c values between -7.36 and -22.9‰) such calculation is rather limited. nevertheless, the geographical distribution of δ13c values in organic carbon (fig. 11) clearly indicates the prevailing influence of terrestrial organic matter in the southern, as well as in the coastal part of element sio2 al2o3 fe2o3 feo mno mgo cao na2o k2o tio2 units % % % % % % % % % % mean 34.75 8.21 2.47 1.7 0.04 6.01 15.22 2.17 1.48 0.49 minimum 22.19 3.99 0.01 0.94 0.02 3.31 5.96 0.53 0.80 0.31 maximum 48.52 14.79 4.30 3.24 0.12 8.19 24.26 3.59 2.59 0.77 element p2o5 ba sr y zr v cu pb zn ag units % ppm ppm ppm ppm ppm ppm ppm ppm ppm mean 0.07 162.44 329.73 22.31 176.00 75.93 32.13 25.09 51.44 minimum 0.04 97.00 102.00 16.00 111.00 37.00 12.00 13.00 25.00 <0.40 maximum 0.33 335.00 578.00 33.00 261.00 133.00 68.00 42.00 87.00 0.50 element ni cd au as br co cr cs hf mo units ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm mean 31.42 13.00 123.33 11.31 112.87 5.24 5.75 minimum 15.00 <0.50 <5 5.00 18.00 6.00 74.00 1.50 3.50 <5 maximum 61.00 0.60 19.00 26.00 410.00 21.00 170.00 12.00 8.70 47.00 element rb sb sc ta th u w la ce nd units ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm mean 78.13 0.95 8.76 10.34 4.43 37.94 79.40 35.76 minimum 30.00 0.40 4.80 <1 5.80 -0.50 <3 24.30 51.00 18.00 maximum 198.00 4.20 17.00 3.00 20.00 11.00 5.00 58.70 126.00 50.00 element sm eu tb yb lu units ppm ppm ppm ppm ppm mean 5.96 1.28 -0.11 2.24 0.36 minimum 4.00 0.80 -0.50 1.20 0.20 maximum 9.60 2.30 1.80 3.80 0.59 table 5 mean, minimum and maximum concentrations of chemical elements in surficial sediment from makirina cove. 37šparica et al.: recent sediments of makirina cove (northern dalmatia, croatia)... the cove, and marine derived organic compounds in the northern and central part of the cove. variations in the carbon isotopic composition of sedimentary organic matter in surficial sediment thus have been noted as a function of the distance from the shore. changes in δ13c values in sediment cores may be related to a varying influx of terrestrial carbon and/ or diagenetic effects. because diagenetic processes in sediments result only in minor differences between the source and the residual carbon, the decrease in 13c content at -25 cm towards shore line undoubtedly reflects a dilution of endogenous marine organic compounds by an increased contribution of terrestrial organic debris in the past, when the sea level was to some extent lower. the relative contribution of marine and terrestrial organic matter to sediments was evaluated from δ13c of the two end members with known and significantly different carbon isotope composition, using the mixing plant stem leaf flower other* agropyron pungens -28.82 -27.98 artemisia coerulescens -24.72 -28.75 -23.42 arthrocnemum fruticosum -27.19 -27.85 arthrocnemum glaucum -24.50 arthrocnemum glaucum -27.78 -26.91 arundo donax -27.39 avena barbata -28.39 -28.46 -26.78 camphorosma monspeliaca -12.04 -13.22 carex -25.83 -26.91 centaurium erythraea -27.79 -30.35 -26.58 clematis flammula -25.75 -24.18 -26.89 crithmum maritimum -27.77 -28.57 dactylis hispanica -26.57 -28.11 -27.62 dancus carota -28.02 -30.04 -27.14 halimione portulacoides -24.52 -23.76 -24.37 halimione portulacoides -25.50 -28.44 -25.11 helichrysum italicum -27.39 -29.80 -28.96 helichrysum italicum -27.39 -29.80 -28.96 helichrysum italicum -28.67 helichrysum italicum -28.33 -26.79 hypericum perforatum -26.26 -23.75 -28.24 subsp. veronense inula chrithmoides -25.12 -24.26 -24.59 inula crithmoides -23.39 -25.63 inula spiraeifolia -30.68 -29.70 inula viscosa -25.15 -27.15 -23.05 juncus acutus -28.97 -29.79 juncus maritimus -27.44 -26.00 juniperus oxycedrus -25.97 -26.79 lagurus ovatus -29.26 -28.76 lavandula angustifolia -27.58 -27.75 -25.92 limonium serotinum -25.44 -26.83 -25.16 limonium serotinum -24.59 -24.69 linum tenuifolium -24.96 -25.56 melica ciliata -26.67 -25.39 myrtus communis -28.00 olea europaea -24.47 -24.90 -29.34 -25.57 olea europaea -27.71 pinus halepensis -29.41 -26.95 24.46 pistacia lenticus -24.55 -26.41 -23.97 puccinelia palustris -28.02 -26.95 reichardia picroides -26.66 -25.52 scabiosa maritima -25.96 -27.90 -26.81 scabiosa triandra -25.71 -28.39 -27.35 schoenus nigricans -28.16 -27.24 spartium junceum -24.35 -24.55 -23.72 spartium junceum -26.06 -25.92 suaeda maritima -24.64 -25.02 codium bursa -17.77 -17.88 -17.14 seagrass (cymadocea nodosa) -9.15 seagrass (cymadocea nodosa) -8.24 -7.36 -7.38 table 6 carbon isotope composition of terrestrial and aquatic plants from makirina cove and pirovac bay. legend: * seed, pollen, root 38 geologia croatica 58/1 equation proposed by calder & parker (1968). for δ13c values of terrigenous (ct) and marine (cm) organic matter in the equation: δ13c = fm δ13cm + ft δ13ct , and fm + ft = 1 the percentage of terrigenous (ft) and marine (fm) organic matter in surficial sedimentary organic matter was determined. for δ13ct the mean value for terrestrial plants (-26.44‰) was used, while for δ13cm a value of -12.68‰ was taken. this value considers the influence of aquatic plants, especially cymadocea nodosa and codium bursa, on the isotopic composition of marine organic matter. the percentage of terrigenous organic matter in sedimentary organic matter is relatively high in the southern coastal part of makirina cove (40–60%). in the central part of the cove the influence of marine inorganic matter is dominant, and the percentage of terrigenous organic matter input is less than 40%. 4.2.5. biogenic carbonate isotope geochemistry the isotopic composition and the mineralogy of the molluscs (plate vii) are shown in table 8 together with the associated isotopic composition of the ambient seawater and δ13c dic values. as can be seen, there is significant isotopic variation between different shells of the same species, at the same site. however, isotopic variations between shells of the same species at different sample sites are even greater (table 8, fig. 12). the cross plot of mollusc δ18o and δ13c (fig. 12) indicates a relatively narrow range of δ18o values (from +1.05‰ to +2.53‰) and a wide range of δ13c values (from -3.26‰ to +2.92‰). the data are roughly separated into two groups, primarily on the basis of δ13c fig. 9 carbon isotope composition of land and marine plants from makirina cove and pirovac bay. fig. 10 isotopic composition of organic carbon in surficial sediment from makirina cove. 39šparica et al.: recent sediments of makirina cove (northern dalmatia, croatia)... values, with one group having δ13c values of <-0.04‰ and the other with values of >0.35‰. the group with lower δ13c values represents molluscs from makirina cove characterized by a shallow marine water environment with intense evaporation and decomposition of sedimentary organic matter. the group with higher δ13c values represents molluscs from pirovac bay and the coastal part of the murter sea. we must point out that the water of makirina cove is enriched with heavy oxygen and light carbon isotopes with respect to the water from pirovac bay and the murter sea (table 8). however, the water from pirovac bay also contains a variable amount of light oxygen and carbon isotopes due to the influence of fresh water from lake vrana through an artificial canal, as well as through numerous submarine sources in the immediate vicinity of the coast in the bay. however, it is only slightly depleted with heavy oxygen and light carbon with respect to the normal seawater of the murter sea. the specimens of the gastropod gourmia vulgata from makirina cove yielded a range of δ18o from +1.47‰ to +1.20‰ and of δ13c from -1.2 to -0.79‰. a larger scatter of isotopic compositions was found in gourmya vulgata shells from pirovac bay (δ18o from +1.05‰ to +1.69‰; δ13c from +0.71‰ to +1.98‰) and the coastal part of the murter sea (δ18o from +1.11‰ to +1.82‰; δ13c from +1.39‰ to +2.92‰). similar low δ18o in the range between +1.24‰ and +1.53‰ and δ13c in the range between -2.40‰ and -2.34‰ were exhibited by shells of the gastropod monodonta turbinata collected in makirina cove. these values are considerably lower than in shells of the same species from the coastal part of the murter sea. their δ18o and δ13c values are up to 1.0‰ and 3.97‰ higher relative to those of monodonta turbinata from makirina cove. mussel shells of nuculana fragilis and levicardium oblongum from makirina cove are also considerably enriched in the light carbon isotope and show slightly lower δ18o values relative to mollusc shells from pirovac bay or the murter sea. profile samp. no. depth interval (cm) δ13c (pdb) ‰ profile samp. no. depth interval (cm) δ13 (pdb) ‰ m1 m1/1–a 0–5 -19.18 m4 m4/3–a 0–5 -16.65 m1 m1/1–e 20–25 -19.91 m4 m4/3–e 20–25 -18.06 m1 m1/2–a 0–5 -13.19 m4 m4/4–a 0–5 -16.77 m1 m1/2–d 20–25 -14.79 m4 m4/4–e 20–25 -19.87 m1 m1/3–a 0–5 -15.40 m5 m5/1–a 0–5 -18.04 m1 m1/3–d 20–25 -13.10 m5 m5/1–d 20–25 -20.54 m1 m1/4–a 0–5 -14.39 m5 m5/2–a 0–5 -17.57 m1 m1/4–e 20–25 -15.98 m5 m5/2–g 20–25 -20.42 m1 m1/5–a 0–5 -13.19 m5 m5/3–a 0–5 -17.32 m1 m1/5–d 20–25 -13.10 m5 m5/3–g 20–25 -22.41 m2 m2/1–a 0–5 -16.29 m5 m5/4–a 0–5 -18.62 m2 m2/1–e 20–25 -16.91 m5 m5/4–f 20–25 -22.29 m2 m2/2–a 0–5 -14.85 m5 m5/5–a 0–5 -18.72 m2 m2/2–d 20–25 -14.11 m5 m5/5–e 20–25 -19.84 m2 m2/3–a 0–5 -17.76 m6 m6/1–a 0–5 -20.28 m2 m2/3–d 20–25 -14.09 m6 m6/1–f 20–25 -20.84 m2 m2/4–a 0–5 -15.89 m6 m6/2–a 0–5 -21.58 m2 m2/4–d 20–25 -14.10 m6 m6/2–f 20–25 -21.95 m3 m3/1–a 0–5 -17.86 m6 m6/3–a 0–5 -21.21 m3 m3/1–e 20–25 -19.18 m6 m6/3–e 20–25 -20.66 m3 m3/2–a 0–5 -15.03 m7 m7/1–e 20–25 -23.99 m3 m3/2–e 20–25 -14.64 m7 m7/2–a 0–5 -19.95 m3 m3/3–a 0–5 -15.26 m7 m7/2–f 20–25 -24.64 m3 m3/3–e 20–25 -15.31 m7 m7/3–a 0–5 -20.01 m3 m3/4–a 0–5 -13.77 m7 m7/3–f 20–25 -23.57 m3 m3/4–d 20–25 -14.83 m8 m8–a 0–5 -24.57 m4 m4/1–a 0–5 -17.76 m8 m8–d 20–25 -25.33 m4 m4/1–e 20–25 -18.51 m9 m9–a 0–5 -21.75 m4 m4/2–a 0–5 -16.63 m9 m9–d 20–25 -23.55 m4 m4/2–e 20–25 -18.94 table 7 isotope composition of organic carbon in surficial sediment from makirina cove. 40 geologia croatica 58/1 variations in the oxygen and carbon isotopic composition of the shells analysed most probably indicate that these molluscs store valuable information about the ambient water isotopic composition of oxygen and carbon, as well as temperature and salinity. in general, molluscs are believed to exert only a minimal vital effect over their isotopic composition (jones, 1985), and thus their isotopic values are representative of environmental water conditions. this study indicates that the oxygen isotope composition of the mollusc shells investigated reflects formation in or near equilibrium with their ambient waters. any variations in the isotopic signatures thus indicate variable environmental conditions and temperature changes. the calculated equilibrium temperatures for mollusc shell aragonite and calcite from the investigated locations give reasonable temperature determinations, which are consistent with those measured from s δ13c org. (pdb) ‰ (20-25cm) s δ13c org. (pdb) ‰ (0-5cm) a b fig. 11 organic carbon isotopic composition of recent sediment from makirina cove. fig. 12 oxygen and carbon– oxygen isotope composition of mollusc shells from makirina cove, murter sea and pirovac bay. 41šparica et al.: recent sediments of makirina cove (northern dalmatia, croatia)... may to november. these molluscs thus seem to precipitate their carbonate skeleton mostly during the warmer period. furthermore, it can be seen that environmental factors affect the carbon isotope composition of mollusc shells. the variations in carbon isotope composition of dissolved inorganic carbon due to oxidation and decomposition of organic matter in makirina cove, as well as the influxes of fresh water into pirovac bay seems to be the most important factors. furthermore, we can also conclude that the δ13c values of shell carbonates are out sample no. mollusc shells mineralogy δ18o (pdb) ‰ δ13c (pdb) ‰ δ18o (smow) ‰ m-10 gourmya vulgata calcite +1.46 -1.09 +32.42 m-11 gourmya vulgata calcite +1.20 -1.20 +32.15 m-12 gourmya vulgata calcite +1.33 -1.01 +32.28 m-9 gourmya vulgata calcite +1.47 -0.79 +32.42 m-2 nuculana fragilis calcite +1.51 -3.19 +32.46 m-13 nuculana fragilis calcite +1.35 -2.80 +32.30 m-14 nuculana fragilis calcite +1.66 -2.83 +32.62 m-6 nuculana fragilis calcite +2.29 -0.04 +33.27 m-3 laevicardium oblongum calcite +1.66 -0.89 +32.62 m-4 laevicardium oblongum calcite +1.48 -0.99 +32.44 m-5 laevicardium oblongum calcite +1.69 -3.26 +32.65 m-16 laevicardium oblongum calcite +1.41 -1.40 +32.36 m-7 monodonta turbinata calcite/aragonite +1.47 -2.39 +32.43 m-8 monodonta turbinata calcite/aragonite +1.53 -2.34 +32.49 m-15 monodonta turbinata calcite/aragonite +1.24 -2.40 +32.19 mu-1 monodonta turbinata calcite/aragonite +2.02 +0.35 +32.99 mu-2 monodonta turbinata calcite/aragonite +2.53 +0.65 +33.52 mu-3 monodonta turbinata calcite/aragonite +1.76 +0.73 +32.72 mu-12 monodonta turbinata calcite/aragonite +1.82 +0.41 +32.79 mu-13 monodonta turbinata calcite/aragonite +2.17 +0.50 +33.15 mu-4 columbella rustica calcite +1.85 +1.49 +32.82 mu-5 gourmya vulgata calcite +1.65 +1.68 +32.61 mu-6 gourmya vulgata calcite +1.11 +1.39 +32.05 mu-7 gourmya vulgata calcite +1.72 +1.44 +32.69 mu-8 gourmya vulgata calcite +1.82 +2.85 +32.79 mu-9 gourmya vulgata calcite +1.29 +2.80 +32.24 mu-10 gourmya vulgata calcite +1.68 +2.90 +32.64 mu-11 gourmya vulgata calcite +1.82 +2.92 +32.79 mu-14 laevicardium oblongum calcite +2.16 +1.30 +33.14 mu-15 laevicardium oblongum calcite +2.27 +1.33 +33.25 mu-16 laevicardium oblongum calcite +2.38 +1.49 +33.36 pz-1 gourmya vulgata calcite +1.38 +0.96 +32.33 pz-2 gourmya vulgata calcite +1.69 +1.76 +32.65 pz-3 gourmya vulgata calcite +1.53 +1.52 +32.49 pz-4 gourmya vulgata calcite +1.65 +1.57 +32.61 pz-5 gourmya vulgata calcite +1.44 +1.57 +32.39 pz-6 gourmya vulgata calcite +1.51 +1.66 +32.47 pz-7 gourmya vulgata calcite +1.39 +1.98 +32.34 pz-8 gourmya vulgata calcite +1.60 +1.85 +32.56 pz-9 gourmya vulgata calcite +1.08 +0.81 +32.02 pz-10 gourmya vulgata calcite +1.19 +0.78 +32.14 pz-11 gourmya vulgata calcite +1.05 +0.71 +31.99 seawater δ18owater (may) δ18owater (august) δ13cdic (may) δ13cdic (august) makirina cove +1.0‰ +2.56‰ -2.31‰ -4.38‰ murter sea +1.0‰ +0.65‰ -0.5‰ -1.0‰ pirovac bay +1.0‰ +0.5‰ -0.5‰ -1.1‰ table 8 oxygen and carbon isotope values and mineralogy of mollusc shells and isotope composition of seawater from makirina cove (m), murter sea (mu), and pirovac bay (pz). 42 geologia croatica 58/1 of the predicted isotopic equilibrium with atmospheric co2. 4.2.6. carbonate saturation state in the pore water to check the saturation state of calcite and aragonite in the pore water, the saturation indices (si) were calculated using the phreeque program package (parkhurst et al., 1980), with equilibrium constants adapted for seawater conditions. the calculated saturation indices in pore water, together with the supernatant in the benthic chambers, (using the values of the solubility products of calcite and aragonite), show that the water was clearly supersaturated with respect to both carbonates (fig. 13). so, the precipitation of authigenic amorphous or crystalline carbonate phases from the pore water in the upper 20 cm of the sediment column was thermodynamically possible. 4.2.7. benthic fluxes in situ benthic fluxes were estimated from linear regressions of solute concentrations vs. time (table 9), and then compared to those calculated from depth profiles of the solute distribution in the pore water. positive fluxes represent an efflux of the solute from the sediment, whereas negative fluxes represent an influx from the supernatant into the interstitial solution. anoxic conditions in the sediments strongly influenced the speciation and benthic fluxes of nitrogen and sulphur, as well as iron. the high benthic flux of dissolved inorganic carbon at both sampling sites is easily explained by decomposition of sedimentary organic matter followed by a decrease in δ13c of released dic which is typical of the increasing influence of organicderived dissolved carbon (mcnichol et al., 1991). the carbon isotopic composition of the dic flux was calculated after lansdown et al. (1992) and boehme et al. (1996) as: fig. 13 saturation indices (si) of calcite and aragonite in the pore water at site m 1/3. in situ benthic flux calculated diffusive flux [mmol m-2day-1] [mmol m-2day-1] solute site 5 site3 site 3 0–120 h 0–240 h mntot 0.20 0.08 – fetot -0.16 0.04 – nh4+ -1.87 -2.03–0.92 -0.58 no3-0.40 -0.15–0.62 -0.28 dic 18.50 12.67 9.81 po4 3-0.004 0.002 0.002 so4 2-33.5 -22.21 – table 9 in situ benthic fluxes at sampling sites m 1/3 and m 1/5 during a 120 and 240-hour incubation experiment, respectively; at site 3, the nh4 + and no3 fluxes were calculated separately for periods from 0–70 h and from 70–240 h. where δ13cdic, t and [dic]t are the isotopic composition and concentration of dissolved inorganic carbon at the two time periods, respectively. δ13cj-dic was found to be -6.7±2.1‰ at site 3 and -8.2±1.6‰ at site 5. δ13c of the sedimentary organic matter, which is assumed to be the predominant source of dic, has been determined to be -15‰ and -16.5‰, respectively at the same sites. carbonate dissolution cannot be considered as a significant source of dic, since the pore water is supersaturated with respect to both calcite and aragonite. methanogenesis is therefore a potential source of 13c-enriched dic producing isotopically light methane, as concluded from the positive correlation between dic 43šparica et al.: recent sediments of makirina cove (northern dalmatia, croatia)... concentration and its δ13c value (lansdown et al., 1992). as it was found in the incubation experiment, methane formation indeed took place in the sediment, producing ch4 with δ13c about -53‰, i.e. a typical value for partially oxidised marine methane (oremland et al., 1987). 4.2.8. solute distribution in pore water eh, ph and solute concentrations vs. depth profiles in the pore water at sampling point 3 are presented in fig. 14. the decreasing ph, as well as increasing total alkalinity and dic concentration with depth, is attributed to the processes accompanying the decomposition of sedimentary organic matter. eh measurement showed that, in spite of the presence of benthic organisms, the sediment was highly reductive even in the uppermost segment, (e.g. below -300 mv 2 cm below the sediment/ water interface). the concentration profiles of solutes in the pore water were described using a one-dimensional model adapted to porous sediments, in the form fig. 14 ph and solute concentration vs. depth profiles in the pore water at sampling point m 1/3. 44 geologia croatica 58/1 of the general diagenetic equation by berner (1980), where advection was taken to be unimportant relative to diffusion over the entire depth interval, and enhanced transport due to irrigation was also not included. if the sediment solute distribution is controlled by one-dimensional vertical transport and reaction processes, the diffusive flux of a constituent across the sediment/water interface, jdiff , is independent of transport (aller, 1980), and can be calculated from fick’s first law. diffusive fluxes calculated from the concentration profiles of dissolved constituents in pore water at site 3 are represented in table 1. these results are in quite good agreement but nevertheless somewhat lower than fluxes measured in situ, although an underestimation of calculated fluxes is regularly reported compared to measured ones (berelson et al., 1990; mcnichol et al., 1991). this is attributed to the topography effect caused by an underestimation of the actual sediment surface area when performing one-dimensional calculations of the fluxes modelled (čermelj et al., 1997). 4.2.9. palynofacies analysis the objectives of the palynofacies analysis were (1) identification of the biological origin of pom, i.e. palynomorph and palynodebris categories and their classification according to their primary facies distribution, (2) estimation of quantitative distribution of the recognized categories, (3) evaluation of the ratios between different categories, and (4) interpretation of the depositional environment. 4.2.9.1. biological origin and classification of palynological organic matter (pom) according to their primary facies distribution, the pom has been classified into land derived (i) and marine derived (ii) palynomorphs and palynodebris groups of categories. to each category, comments on biological origin, shape, relative preservation of the structure, framboidal pyrite inclusions (fpi) and relative fluorescence intensity (fi) have been added. i. land derived palynomorphs and palynodebris a. black particles; oxidized woody tissue, mostly angular in shape, no fluorescence. b. brown to yellow particles; woody tissue (skeleton and vascular tissue and vegetal cell wall tissue of higher plants), semi-angular to rounded shape, low to medium preserved structure, low to moderate fi (plate ix, figs. 1–4). c. cuticular tissue; leaf remains, semi-angular to angular shape, low to medium preserved structure, often with fpis, medium to high fi (plate viii, fig. 1). d. spores; pterydophytes, low to medium preservation, medium to fi. e. pollen; gymnosperms and angiosperms, low to medium preservation, often with fpis, high fi (plate viii, fig. 2). f. land derived structureless organic matter; various land plant tissue, morphology ranges from membranous, filamentous, homogenous, often pseudoamorphous, partly with fpis, low to high fi, in this category small homogenous globulae of cellular secretions of leaf-parenchyma and resins/waxes with high fi are also included (plate viii, figs. 8 and 9; plate ix, figs. 1–4). ii. marine derived palynomorphs and palynodebris a. organic walled dinoflagellate cysts; phytoplankton, low to medium preservation, often with fpis, high fi (plate viii, fig. 3). b. tintinnid chitinous loricae; zooplankton, medium to well preserved, often with fpis, no fluorescence (plate viii, fig. 5). c. foraminiferal test linings; chitinous inner walls of benthic foraminifera, medium to well preserved, often with fpis, no fluorescence (plate viii, fig. 4). d. chitinous skeletons; planktonic crustaceans, moderately preserved, often with fpis, no fluorescence (plate viii, fig. 6). e. scolecodonts, chitinous teeth of annelids, benthic, medium to well preserved, no fluorescence (plate viii, fig. 7). f. marine macrophyta (seagrass, seaweeds); well preserved, some irregular structure, membranous, filamentous, fibrous, transculent, high fi (plate viii, figs. 8 and 9; plate ix, figs. 1–4), g. marine derived amorphous organic matter (aom); various marine organisms, derived mostly from phytoplankton, various bacteria, marine macrophyta and faecal pellets, morphology ranges from disseminated, granular, aggregated granular (heterogenous– liptodetrinitic), spongy (homogenous–liptinic), with fpis, moderate to high fi (plate viii, figs. 8 and 9; plate ix, figs. 1–4). 4.2.9.2. quantitative distribution of the categories of pom the overall palynological composition indicates that the analysed samples contain about 32% land derived (i) and 68% marine derived (ii) organic matter (table 10). the palynomorphs constitute about 1.4% of sedimentary organic matter (som). zooplanktonic palynomorphs are most abundant (41.5%), followed by foraminiferal test linings (21.6%), pollen, predominantly coniferalean bisaccate type (21.5%), organic walled dinoflagellate cysts (7.7%) and spores (7.7%) (table 11). the ratio i/ii (land derived/marine derived) may be regarded as an indicator of the proximo–distal position of the sediments related to shore line (tyson, 1995). the values of this ratio (table 12) increase along the transect landwards indicating higher input of terrestrial organic matter near shore. the ratio phytoplankton/zooplankton (iia/iib, d) may reflect changes in the composition of primary 45šparica et al.: recent sediments of makirina cove (northern dalmatia, croatia)... bioproduction, which is controlled through many variable ecological factors (viličić, 1989; viličić et al., 1998). it has to be emphasized that this ratio and its interpretation is closely related to the varying preservation potential of organic matter within different environments. the values of this ratio (table 12) are variable along the transect, which may indicate some variations in primary production. the ratio dinosporin cysts/chitinous exoskeletons of crustaceans (iia/iid) is a ratio of relatively high resistant/low resistant components of organic matter. from a chemical point of view, chitin (polysaccharides) represent relatively low resistant components with a relatively low preservation potential. however, their preservation potential may vary within different environmental conditions, and is closely related to the processes of degradation; in recent sediments, chitinoclastic bacteria are responsible for most chitin breakdown that occurs in the upper aerobic zone, a marked slowdown or cessation of bacterial activity may occur in anoxic conditions and, under conditions of high productivity and high sedimentation rate, the preservation potential of chitinous remains in surficial sediments may become considerably enhanced (van waveren & visscher, 1994). chitinous material is moderately preserved in the makirina sediments, indicating very low activity of chitinoclastic bacteria. this ratio may potentially be high and may still contain preserved chitinous material. therefore, higher near shore values of the ratio may suggest some variations in primary production as the environmental conditions were conducive to preservation of chitinous material. the values of this ratio (table 12) are low and variable along the transect. the ratio structured/amorphous (ib–e, iia–f/ if, iig) reflects the pattern and the relative degree of organic matter degradation and preservation of sedimentary organic matter (som), which is closely related to a complex interaction of several factors before, during and after its deposition; primary bioproduction, preservation potential of organic matter, sinking rate, sedimentation rate, oxic–anoxic relationships within the depositional environment, proximo–distal position to source of terrestrial organic matter and granulometry of the sediments are the most important ones. in order to emphasize the relative degree of organic matter degradation, the category if is treated as “amorphous”, although it is mostly structureless, thus not really amorphous. this is because bacterial degradation of some primary structured organic matter results in secondary structureless organic matter. unaltered som consists of structured organic matter, structureless organic matter and amorphous organic matter (aom), and with the exception of chitin and lignin, all other constituents of som are more or less hydrogen-rich and lipid-rich, thus exhibiting fluorescence properties under excitation of uv or blue light. it has been demonstrated that the preservation of palynomorphs is possible in environments where the aerobic and anaerobic processes are short and/or weak enough during sedimentation and diagenesis (orr & gaines, 1973; hart, 1986). consequently, som is well preserved within conditions which mostly com samples m i/4 m i/7 m i/10 (%tpom) (%tpom) (%tpom) ia 0.4 0.7 5.7 ib 6.7 7.2 18.0 ic 0.3 0.2 0.2 id 0.1 0.1 0.1 ie 0.3 0.4 0.2 if 20.0 20.0 15.0 iia 0.1 0.1 0.1 iib 0.1 0.1 0.1 iic 0.3 0.4 0.2 iid 0.4 0.5 0.2 iie 0.1 0.1 0.1 iif 1.2 0.2 0.1 iig 70.0 70.0 60.0 σ% 100.0 100.0 100.0 table 10 quantitative distribution of the categories of pom (% of total pom). samples m i/4 m i/7 m i/10 (%tp) (%tp) (%tp) id 7.2 5.9 10.0 ie 21.3 23.4 20.0 iia 7.2 5.9 10.0 iib 7.2 5.9 10.0 iic 21.4 23.5 20.0 iid 28.5 29.5 20.0 iie 7.2 5.9 10.0 σ% 100.0 100.0 100.0 table 11 quantitative distribution of palynomorphs (% of total palynomorphs). samples m i/4 m i/7 m i/10 i / ii 0.39 0.41 0.64 iia / iib, d 0.20 0.16 0.33 iia / iid 0.25 0.20 0.50 ib-e, iia-f / if, iig 0.11 0.11 0.25 ia, iib-e / ib-f, iia, f,g 0.014 0.018 0.067 ia / ib 0.06 0.10 0.31 table 12 ratios of the categories of pom. 46 geologia croatica 58/1 prise dysoxic and/or environments with high sedimentation rate, where the palynological record would reveal preserved primary structure of som and its primary fluorescence properties. however, depending on the type, intensity and duration of bacterial degradation within different aquatic depositional environments, som may convert partly or completely, according to the preservation potential of each component, into organic matter with various morphological and fluorescence properties. so, in depositional sets with dysoxic conditions and/ or high sedimentation rate, the ratio structured/amorphous is mostly dependant on quantity of primary aom which is well preserved due to favourable conditions. in contrast, this ratio is, in oxic and anoxic environments, mostly dependant on degradation, resulting in varying qualities of organic matter as compared to unaltered material. experiments have shown that plant tissue may convert into structureless, semi-amorphous organic matter under oxic conditions (masran & pocock, 1981). however, this type of organic matter does not exhibit fluorescence properties. even very resistant lipid-rich components, both land (cuticles) and marine (dinocysts) derived, loose their fluorescence features and often their primary structure. non-fluorescent chitinous organic matter is degraded in oxic environments and it often appears as amorphous. in general terms, the palynological record of oxic environments does not contain fluorescent structureless organic matter or fluorescent aom, although a high sedimentation rate may be conducive to preservation of some primary fluorescent aom which is otherwise degraded into non-fluorescent aom revealing features of an land plant origin. this is important to differentiate, because “humic” aom is also produced in large amounts by the biodegradation of planktonic or microbial mat organic matter (tyson, 1995). on the other hand, palynofacies of anoxic environments are dominated by fluorescent organic matter, represented by varying amounts of structured, structureless and amorphous organic matter which is dependant on the overall environmental conditions and preservation potential. the biological praecursors, i.e. the source of fluorescent organic matter are hydrogen-rich, i.e. lipid-rich components, both land derived (cellulose, poorly lignified tissue, suberine, suberified tissue, cuticle, leaf parenchyma secretions, resins, waxes, spores, pollen) and marine derived (algae, phyto-, zooplankton, lipids of various organisms including a variety of bacteria as well as poorly lignified vascular and non-vascular tissue of marine macrophytes). lipid-rich constituents are resistant to anaerobic bacterial degradation, whereas others, for example primary structured woody tissue (s.l.), are, under the same conditions, converted into structureless organic matter showing fluorescence features. fluorescent aom may be regarded as a product of the decomposition of algae, phyto-, zooplankton and bacteria with a contribution of bacterially altered land plant tissue (stach et al., 1982; tissot & welte, 1984; robert, 1988; tyson, 1995; batten, 1996). however, typical aom, as the term should be used, consists of primary aom of organic aggregates derived from phytoplankton blooms, and particulate organic matter of sea water as well as algal and zooplankton extracellular exudates. the same holds true for algal mats formed by cyanobacteria (“blue-green algae”) and thiobacteria (sulphur bacteria), because the preservation potential of their structured sheets is very low and they are rapidly degraded. palynological examination of modern deposits with cyanobacterial mats has shown that all but the surficial layers contain only aom (tyson, 1995). aom is also derived from other sources. part of aom is represented by the faecal remains of zooplankton feeding on phytoplankton and other organic material (habib & miller, 1989). in some organic-rich sediments, faecal pellets compose a significant part of aom (robbins et al., 1996). due to degradation and fragmentation during and after deposition, faecal remains often occur as numerous small aggregates. in this case, palynofacies containing abundant aom, bisaccate pollen, dinoflagellate cysts and acritarchs may infer the presence of faecal pellets (habib et al., 1994). fluorescent faecal pellets are considered to be of zooplanktonic origin, and were probably deposited in anoxic environments, whereas non-fluorescent ones indicate a benthic origin and oxic environments (robbins et al., 1996). finally, sediments of some shallow water environments may contain abundant aom derived from marine macrophytes. due to the fact that they are easily degraded, they appear in modern sediments mostly as amorphous aggregates (tyson, 1995). sediments of anoxic depositional sets yield various amounts of fluorescent aom and fluorescent structureless organic matter depending on primary production, proximo–distal position and the amount of terrestrial organic matter input. fine-grained sediments of distal, basinal, anoxic environments contain entirely typical aom which is ultimately derived from phytoplankton and bacteria (lewan, 1986; raynaud et al., 1989; tyson, 1995; batten, 1996). fine-grained sediments of proximal, shallow marine, anoxic environments contain typical aom in lower concentrations, due to the proximity to the source of terrestrial organic matter, but also a certain amount of land and marine derived structureless organic matter, (partly primary structureless, partly derived from microbially altered organic matter). nevertheless, sediments of all anoxic environments are usually dominated by typical aom. expressed as percentages, high values of typical aom with high fluorescence intensity are indicators of reducing, i.e. at least temporarily dysoxic to anoxic environments with high preservation of autochthonous planktonic organic matter or benthic microbial mat organic matter (tyson, 1995). within the sediments of the central part of makirina cove, approximately 70% of typical aom has been estimated, decreasing landwards along the transect to 60% due to the increased input of terrestrial organic matter (table 10). 47šparica et al.: recent sediments of makirina cove (northern dalmatia, croatia)... low values of the ratio structured/amorphous (table 12) slightly increase landwards along the transect and they suggest a relatively high degree of degradation and preservation of organic matter resulting in accumulation of fluorescent aom and fluorescent structureless organic matter as indicators of oxygen-depleted conditions. the ratio non-fluorescent/fluorescent organic matter (iib–e/ib–f, iia, iif, iig) is herein evaluated as an indicator of the organic matter organic matter preservation, i.e. as a relative indicator of oxidation processes which may have affected primary fluorescent organic matter before, during and after deposition. any oxidation of fluorescence categories would result in a certain loss of fluorescence intensity or lack of fluorescent properties. the most labile of them is the finely divided and spongy fraction of fluorescent aom. the lack of fluorescence of this fraction mainly indicates partial oxidation before or during final deposition (tyson, 1995). this type of aom has not been identified within the analysed sediments. however, aom of near shore samples needed 3 minutes of excitation in blue light before reaching the same fluorescence intensity and colour spectrum as exhibited by other samples almost immediately after the beginning of excitation. this may indicate very weak and/or very short oxidation probably after deposition (activity of benthic organisms), because oxidation before or during the deposition would have resulted in a stronger reduction, if not completely, of fluorescence intensity. an important indicator that oxidation processes before, during and after deposition have left little signature on organic matter of makirina sediments is the fact that all but primary non-fluorescent organic matter (lignin and chitin) consists of fluorescent organic matter. very low values of this ratio slightly increase landwards indicating a high degree of preservation of organic matter and protection against secondary oxidation. the ratio ia/ib indicates the degradation pattern. unaltered woody tissue reveals fluorescence properties and once they become settled in the sediment, may suffer various alterations depending on the oxic–anoxic relationships of different environmental conditions. oxidation processes remove fluorescent components and convert organic matter either into non-fluorescent aom or dark to black organic clasts. anaerobic bacterial degradation converts woody tissue into structureless organic matter with some fluorescence properties. in general, black organic clasts (ia) suggest biodegradation under oxic conditions, i.e. various wet but not saturated environments, where rooting and fungal activity took place (batten, 1996), whereas brown-yellow, structureless organic clasts (ib) suggest bacterial degradation under anoxic conditions (tyson, 1995). the higher the ratio, the more oxic conditions prevail and, vice versa, the lower the ratio, the more anoxic conditions prevail. the palynological record of environments with a strong terrigenous input of black organic clasts may exhibit a relatively high ia/ib ratio even if anoxic conditions prevail in environments where these organic clasts are finally deposited. therefore, this ratio should be evaluated together with the ratios of structured/amorphous and non-fluorescent/fluorescent organic matter. the values of this ratio slightly increase landwards along the transect suggesting anoxic degradation pattern of organic matter. 4.2.9.4. depositional environment according to the palynological composition of both type and amount of organic matter, the recent sediments of makirina cove may be characterized as organic-rich deposits. this is consistent with the organic carbon values representing up to 5 wt.% of the total sediment (lojen et al., 1999). the high amount of organic matter, of which 2/3 is marine derived, suggests that the makirina sediments originate within an environment with high primary bioproduction and conditions which are conducive to its preservation. an important indicator of primary bioproduction is the quantity of phytoplankton which enables determination of the trophic level of marine ecosystems. the development of phytoplankton populations is controlled through a combination of ecological factors (supply and concentration of nutrients, thermohaline relationships, and light) where hydrography, influenced by specific karst-hydrology, plays an important role (viličić et al., 1998; carić et al., 1999; burić et al., 1999). studies of recent phytoplankton along the croatian coast have shown that ecosystems similar to makirina cove are moderately eutrophic (viličić, 1989; viličić et al., 1998).the palynological record of the makirina sediments shows a relatively high proportion of typical marine aom which is in general terms derived from phytoplankton and bacteria. very low abundances of dinosporin cysts, i.e. low values of the ratio phytoplankton/zooplankton, can be explained in terms of the ecological conditions where the motile stage of dinoflagellate communities prevailed and the production of their cysts is reduced (tyler et al., 1982; tyson, 1987, 1995). this means that dinoflagellates must have contributed more biomass than is actually recorded in the palynological composition. a similar palynological relationship has also been recorded in recent sediments of the restricted, shallow marine (<2.5m) environment of morinje bay (20 km se from makirina cove), where the phytoplankton quantity of the sea water column indicates a moderately eutrophic ecosystem (koch et al., 2002; bačani et al., 2004). in addition, stressed, shallow marine eutrophic environments are characterized by populations of small, opportunistic foraminiferal species (hallock, 1988), which is consistent with the palynological record of the makirina sediments which contain small-sized foraminiferal test linings. studies of the area under consideration have indicated sea-level rise during the holocene and up to the present (šegota, 1982; filipčić, 1992), which is also considered to be a factor that influences primary bioproduction: the formation of marine, organic-rich sediments often coincides with transgression (tyson, 1987, 1989, 1995; tyson & 48 geologia croatica 58/1 funnell, 1987; tribovillard & gorin, 1991; steffen & gorin, 1993; batten, 1996). the organic matter of makirina sediments is characterized by abundant inclusions of framboidal pyrite indicating reducing conditions and a supply of reactive iron. pyrite is typically most abundant in anoxic environments and occurs together with aom (stach et al., 1982; tissot & welte, 1984; robert, 1988; tyson, 1995, batten, 1996). however, in anoxic environments with a low supply of iron, the formation of pyrite is rather limited (berner, 1981; allison, 1990). as most of the iron is detrital in origin, within anoxic environments with a low iron supply, such as carbonate facies, pyrite formation is limited and the sulphur is incorporated into organic molecules (tissot & welte, 1984; moldowan et al., 1992; jerinić et al., 1994; tyson, 1995). therefore, the content of pyrite is often positively correlated with both siliciclastics and the relative percentage of terrestrial organic matter (tyson, 1995) which is the case in the makirina sediments. however, due to the carbonate sorroundings of makirina cove, the source of iron and the mechanism of its supply is at present insufficiently understood. in spite of obvious benthic activity within the shallow marine environment of makirina cove, oxidation processes which might have affected organic matter before, during and after the final deposition had no or very little impact on its preservation state. most of the organic matter of makirina sediments consists of fluorescent material and a relatively high portion of aom, indicating a high degree of preservation which is possible only under oxygen-depleted conditions. therefore, it is suggested that the anoxic/oxic conditions are delineated at or very near the sediment/water interface. this may find support in terms of the presence of cyanobacteria which are widely distributed in shallow environments with fluctuating salinities where they may flourish at salinities of 40–250‰ (tyson, 1995). as the salinity in makirina cove varies during the summer period between 40–41‰ (lojen et al., 2000), the cyanobacteria may have formed mat structures which reduce the vertical permeability of the sediment, helping to retain the saline anoxic pore waters. these conditions encourage the preservation of the lipoid fraction which is refractory to anaerobic bacteria (tyson, 1995). the high preservation degree of aom also reflects the stable environmental conditions of makirina cove, preventing lateral flushing of depositional pore waters and the introduction of aerobic bacteria (tyson, 1995). in general terms, the oxygen depleted conditions and accompanying marine transgression in restricted environments mostly control the preservation of aom (tyson, 1995; batten, 1996). in addition, the burial rate and preservation of organic matter is positively correlated with sedimentation rate (betts & holland, 1991; tyson, 1995), which is in makirina cove estimated at 0.75 m/1000 y in the central part of the cove. 5. conclusion on the basis of the multidisciplinary investigation of the recent sediments from makirina cove, the following conclusions regarding their origin may be outlined: (1) the albian–cenomanian dolomite basement of the makirina depression was inundated by the sea approximately 4500 y b.p. due to the holocene sealevel rise. the morphological features of the surrounding land and the geometry of the depositional basin, as well as the balanced relationship between the ongoing holocene sea-level rise and the sedimentation rate, enabled formation of a restricted, shallow marine (<2 m) environment which persists up to the present time. makirina cove represents a stressed environment with seawater temperatures varying during the year from 0–35ºc and fluctuating salinities reaching values up to 41‰ caused by seasonally enhanced evaporation, a continuous freshwater supply through low capacity submarine springs associated with the coastal karst area and surface runoff episodes. these environmental conditions have been conducive to high primary production of organic matter resulting in the formation of overall organic-rich deposits which contain up to 5 wt.% of organic carbon. during approximately 4500 years, up to 3.5 m of sediments were deposited, indicating a relatively high sedimentation rate estimated at 0.75 m/1000 y in the northern central part of the cove. (2) the recent sediments are composed of weakly sorted clayey–sandy silts. of the non-carbonate minerals, clays predominate over quartz, and lesser amounts of halite, pyrite and marcasite are present. the carbonate minerals are represented by dolomite and amorphous calcite which are more abundant than authigenic calcite and aragonite. the content of clay minerals, halite, pyrite, marcasite and aragonite is highest in the central part of the cove decreasing towards the shore, whereas quartz, dolomite and calcite are inversely distributed. the mineralogical composition of the relatively high concentrations of light and heavy mineral fractions indicates reworking from eocene flysch deposits, which remains puzzling because the surroundings of makirina cove are built-up of cretaceous carbonate rocks lacking these fractions. the morphometric features of the resistant minerals show that some of them have been transported for long distances and resedimented in several cycles. (3) the majority of trace elements are similar to those reported for argillaceous sediments and shales. some of them show values similar to those of the surficial sediments from the central adriatic, while others are higher. nevertheless, most of chemical elements (fe, na, ti, p, as, ba, br, ce, co, cs, cu, eu, la, lu, nd, ni, pb, sc, sm, th, u, v, y, yb, zn) of the surfical sediment from makirina are associat49šparica et al.: recent sediments of makirina cove (northern dalmatia, croatia)... ed with clay minerals within the clay fraction. their increasing concentrations have been found to correlate with distance to shore and with depth. some of the major elements, such as iron, are principally associated with the silt–clay fraction and show similar distributions to k and al. the occurrence of iron sulphide suggests that they are a product of the oxidation of organic matter by microbial mediated sulphate reduction. the presence of ca, mg and sr is associated with the carbonate content of the surroundings with increasing values towards the shore. sediments of the central northern part of the cove are characterised by elevated concentrations of some trace elements (v, zn, cu, ni, pb, as, cs, br, sb, sc, rb, th), especially mo and se, indicating reducing conditions, which is consistent with the same distributional pattern of sulphides. selenium is preferentially enriched in authigenic pyrite, and it is probably the major source of se in the makirina cove sediments. (4) the organic carbon isotopic (δ13c) composition of the sedimentary organic matter shows that the surficial sediments of the southern coastal parts of the cove contain 40–60% terrigenous organic matter, whereas in the central northern part less than 40%. the variations in the carbon isotopic composition have been noted as a function of the distance from the shore. (5) the oxygen isotopic (δ18o) composition of the mollusc shells reflects formation at or near equilibrium with their ambient waters. the molluscs precipitated their carbonate shells mostly during warmer periods (may to november). environmental factors affected the carbon isotopic composition of mollusc shells. variations in carbon isotopic composition are caused by dissolved inorganic carbon due to oxidation and decomposition of organic matter as well as by influxes of fresh water into the bay. it is concluded that the δ13c values of shell carbonates are out of the predicted isotopic equilibrium with atmospheric co2. (6) the saturation indices show that the water was clearly supersaturated with respect to carbonates, meaning that the precipitation of authigenic amorphous or crystalline carbonates phases was thermodynamically possible from the pore water in the upper 20 cm of the sediment column. (7) anoxic conditions in the sediments strongly influenced the speciation and benthic fluxes of nitrogen and sulphur, as well as iron. the high benthic flux of dic is explained by decomposition of sedimentary organic matter followed by a decrease in δ13c of released dic, which is typical of the increasing influence of organic-derived dissolved carbon. as carbonate dissolution cannot be considered as a significant source of dic, since the pore water is supersaturated with respect to both calcite and aragonite, methanogenesis is a potential source of 13c-enriched dic producing isotopically light methane. it has been found that methane formation took place in the sediment, producing ch4 typical for partially oxidized marine methane. (8) the decreasing ph, as well as increasing total alkalinity and dic concentration with depth is attributed to processes accompanying decomposition of the sedimentary organic matter. eh measurement showed that, in spite of the presence of benthic organisms, the sediment was highly reductive even in the uppermost segment, 2 cm below the sediment/ water interface. (9) palynological analysis shows that most of the organic matter (70–90%) consists of hydrogen-rich and lipid-rich amorphous and structureless material with framboidal pyrite inclusions, indicating accumulation and bacterial decomposition of both marine and land derived organic matter under oxygen-depleted conditions. the sediments of the central part of the cove contain 70% marine derived organic matter, decreasing to a level of 60% near the shore. a relatively high portion of typical marine aom, which is derived from phytoplankton, bacteria and marine macrophyta, suggests at least moderately eutrophic conditions of the makirina ecosystem. the combination of nutrient supply through continuous transgression, submarine springs and seasonal run-off episodes enhanced the primary bioproduction. according to the quality and quantity of organic matter, most of the primary biomass, although microbially altered, is well preserved under conditions of oxygen deficiency, accompanying marine transgression and a relatively high sedimentation rate. according to the results obtained from the applied methods, the features of makirina sediments strongly reflect the given depositional conditions within this restricted, stressed, shallow-marine environment, where these organic-rich sediments originate, and may therefore serve as a calibration standard in further investigations. acknowledgements we are indebted to đuro benček, former head of geological and palaeontological department of the institute of geology, zagreb, josip crnko and mato brkić for the assistance in field work. their participation in discussions as well as their suggestions greatly improved the quality of this paper. 6. references aller, r.c. (1980): quantifying solute distributions in the bioturbated zone of marine sediments by defining an average microenvironment.– geochimica et cosmochimica acta, 44, 1955–1965. 50 geologia croatica 58/1 allison, p.a. (1990): pyrite.– in: briggs, d.e.g. & crother, p.r. (eds.): palaeobiology – a synthesis. blackwell scientific publications, oxford, 253–255. appelo, c.a.j. & postma, d. (1994): geochemistry, groundwater and pollution.– a.a. balkema, 536 p. bačani, a., koch, g., bergant, s., šparica, m., viličić, d., dolenec, t., vreča, p. & ibrahimpašić, h. (2004): origin of recent organic-rich sediments from morinje bay (northern dalmatia, croatia): aspects of hydrological and hydrogeological impact.– 32nd international geological congress florence 2004, abstracts, 901. batten, d.j. (1996): palynofacies and palaeoenvironmental interpretation.– in: jansonius, j. & mcgregor, d.c. (eds.): palynology: principles and applications. american association of stratigraphic palynologists foundation, 3, 1011–1064. berelson, w.m., hammond, d.e., o’neal, d.o., xu, x.-u. & zukin, j. (1990): benthic fluxes and pore water studies from sediments of the central equatorial north pacific: nutrient diagenesis.– geochimica et cosmochimica acta, 54, 3001–3012. berner, r.a. (1980): early diagenesis – a theoretical approach.– princeton university press, new jersey, 256 p. berner, r.a. (1981): a new geochemical classification of sedimentary environments.– journal of sedim. petrology, 51/2, 359–396. betts, j.n. & holland, h.d. (1991): the oxygen of ocean bottom waters, the burial efficiency of organic carbon, and the regulation of atmospheric oxygen.– palaeogeogr., palaeoclimatol., palaeoecol., 97, 5–18. beug, h.j. (1961): beiträge zur postglacialen florenund vegetationsgeschichte süddalmatiens: der see “malo jezero” auf mljet, teil 1: vegetationsentwicklung.– flora, 150, 600–630. beug, h.j. (1977): vegetationsgeschichtliche untersuchungen im küstenbereich von istrien.– flora, 166, 357–381. boehme, s.e. , blair, n.e. , chanton, j .p. & martent, c.s. (1996): a mass balance of 13c and 12c in an organic-rich methane-producing marine sediment.– geochimica et cosmochimica acta, 60/20, 3835–3848. bogner, d., juračić, m., odžak, n. & barić, a. (1998): trace metals in fine grained sediments of the kaštela bay, adriatic sea.– water science and technology, 38/11, 169–175. bogner, d., juračić, m., barišić, d., müller, j. & barić, a. (2003): shift from siliciclastic to carbonate sedimentation in the raša river estuary (istria, croatia).– 22nd ias meeting of sedimentology, opatija, abstracts book, 19. burić, z., viličić, d., orlić, m., smirčić, a., kršinić, f., gršetić, z. & caput, k. (1999): termohalini odnosi i raspodjela planktona u estuariju rijeke zrmanje (listopad 1998) (thermohaline relations and distribution of plankton in the zrmanja river estuary, croatia).– 2. hrvatska konferencija o vodama. hrvatske vode od jadrana do dunava, dubrovnik, 277–282. calder, j.a. & parker, p.l. (1968): stable isotope ratios of indices of petrochemical pollution of aquatic environments.– environmental science and technology, 2, 535– 539. carić, m., viličić, d. & jasprica, n. (1999): molarni omjeri hranjivih soli u estuarijima zrmanje i omble (molar ratios of nutritious salts in the zrmanja and ombla estuaries, croatia).– 2. hrvatska konferencija o vodama. hrvatske vode od jadrana do dunava, dubrovnik, 305– 309. cattaneo, a., correggiari, a., langone, l. & trincardi, f. (2003): the late-holocene gargano subaqueous delta, adriatic shelf: sediment pathway and supply fluctuations.– marine geology, 193, 61–69. cescon, b., macchi, g., scarazzato, p. & paul, j. (1975): interstitial water composition in some small cores from the northern adriatic sea.– thalassia jugoslavica, 11, 153–154, zagreb. crusius, j. & thomson, j. (2003): mobility of authigenic rhenium, silver and selenium during post-depositional oxidation in marine sediments.– geochimica et cosmochimica acta, 67, 265–273. crusius, j., calvert, s., pedersen, t. & sage, d. (1996): rhenium and molybdenum enrichments in sediments as indicators of oxic, suboxic and sulfidic conditions of deposition.– earth and planetary sci. lett., 145, 65–78. cutter, g.a. & bruland, k.w. (1984): the marine biogeochemistry of selenium: a re-evaluation.– limnol. oceanogr., 29, 1179–1192. čermelj, b., betruzzi, a. & faganeli, j. (1997): modelling of pore water nutrient distribution and benthic fluxes in shallow coastal waters (gulf of trieste, northern adriatic).– water air soil pollut., 99, 435. ćosović, v., juračić, m., bajraktarević, z. & vaniček, v. (2002): benthic foraminifers of mljet lake (croatia) – potential for (paleo)environmental interpretation.– memorie della societa geologica italiana, 57, 533– 541. daniels, c.h. von (1971): seasonal dynamic variations in benthic foraminiferal assemblages in the limski kanal north of rovinj.– thalassia jugoslavica, 7, 25, zagreb. epstein, s. & mayeda, t. (1953): variation of 18o content of waters from natural sources.– geochim. cosmochim. acta, 4, 213–224. filipčić, a. (1992): neolitsko naselje danilo kod šibenika i razina jadranskog mora (neolithic settlement danilo near šibenik and the level of the adriatic sea).– geograf. glasnik, 54, 33–44, zagreb. fütterer, d. (1969): die sedimente der nördlichen adria vor der küste istrien.– göttinger arb. geol. paläont., 3, 57. fütterer, d. & paul, j. (1976): recent and pleistocene sediments off the istrian coast (northern adriatic).– senckenbergiana marit., 8, 1–21. gladney, e.s. & burns, c.e. (1984): 1982 compilation of elemental concentration data for the usgs geochemical exploration reference samples gsr–1 to gsr–6.– geostandard newsletters, 8/2, 119–154. 51šparica et al.: recent sediments of makirina cove (northern dalmatia, croatia)... golubić, s., le campion-alsumard, t. & schneider, j. (1977): the salt works of sečovlje (portorož, yugoslavia): a natural model for geochemistry and microbiology of evaporitic environments.– rapp. comm. int. mer méditerranée, 24, 125–126. govorčin, d.p., juračić, m., horvatinčić, n. & onofri, v. (2001): holocene sedimentation in the soline channel (mljet lakes, adriatic sea).– natura croatica, 10/4, 247–258, zagreb. grasshoff, k., ehrhardt, m. & kremling, k. (1983): methods of seawater analysis.– verlag chemie gmbh, weinheim, 419 p. hallock, p. (1988): diversification in algal symbiont-bearing foraminifera: a response to oligotrophy?– revue de paléobiologie, 2, 789–797. hart, g.f. (1986): origin and classification of organic matter in clastic systems.– palynology, 10, 1–23. habib, d. & miller, j.a. (1989): dinoflagellate species and organic facies evidence of marine transgression and regression in the atlantic coastal plain.– palaeogeogr., palaeoclimatol., palaeoecol., 74, 23–47. habib, d., eshet, d. & van pelt, r. (1994): palynology of sedimentary cycles.– in: traverse, a. (ed.): sedimentation of organic particles. cambridge university press, 311–335. hall, g.e.m. & pelchat, j-c. (1997): analysis of geological material for bismuth, antimony, selenium and tellurium by continuos flow hydride generation inductively coupled plasma mass spectrometry. part 2, methodology and results.– journal of analytical atomic spectrometry, 12, 103–106. jednačak-bišćan, j. & juračić, m. (1987): organic matter and surface properties in the estuarine mixing zone.– marine chemistry, 22, 257–263. jerinić, g., jelaska, v. & alajbeg, a. (1994): upper cretaceous organic-rich laminated limestones of the adriatic carbonate platform, island of hvar, croatia.– aapg bulletin, 78/8, 1313–1321. johnson, t.c., ewans, j.e. & eisenrich, s.j. (1982): total organic carbon in lake superior sediments: comparison with hemipelagic and pelagic marine sediments.– limnol. oceanogr., 27, 481–490. jones, d.s. (1985): growth increments and geochemical variations in the molluscan shell.– in: broadhead, t.w. (ed.): molluscs. univ. of tennesee, knoxville, tenn. stud. geol., 13, 72–87. juračić, m. & pravdić, v. (1991): the role of suspended matter in assessing the assimilative capacity. case study of two estuaries in the adriatic sea.– chemistry and ecology, 5, 241–248. juračić, m. & prohić, e. (1991): mineralogy, sources of particles and sedimentation in the krka river estuary (croatia) (mineralni sastav, izvori čestica i sedimentacija u estuariju rijeke krke).– geol. vjesnik, 44, 195–200. juračić, m., sondi, i. & pravdić, v. (1992): recent sedimentation in the raša river estuary (istria, croatia): are sediments a sink for pollutants?– 12. intern. symp. “chemistry of the mediterranean – evidence of anthropogenic tempering with marine ecosystem”, rovinj, 32–35. juračić, m., sondi, i., milat, o. & gušić, i. (1998): aragonite sedimentation in a restricted marine environment (mljet lakes, adriatic sea).– in: maldonado, a., millot, c., fowler, s. & guttnick, d. (eds.): rapport du 35e congres de la ciesm. 76–77. koch, g., alajbeg, a., šparica, m. & bergant, s. (2000): palinofacies, organska geokemija i sedimentologija subrecentnih taloga morinjskog zaljeva (srednja dalmacija, hrvatska) – prinos poznavanju procesa nastanka prekurzora matičnih stijena (palynofacies, organic geochemistry and sedimentology of recent sediments from morinje bay (middle dalmatia, croatia) – a contribution to the knowledge of the formation processes of kerogen precursor of source rocks).– in: vlahović, i. & biondić, r. (eds.): 2. hrvatski geološki kongres (second croatian geological congress), cavtat–dubrovnik. zbornik radova (proceedings), 265–271. koch, g., šparica, ma., bergant, s., alajbeg, a., viličić, d., lampret, t., dolenec, t. & šparica, m. (2002): recent sediments (peloids) from morinje bay (middle dalmatia, croatia): their origin and anthropogenetic pollution viewed through a multidisciplinary approach.– the third international congress “enviromental micropaleontology, microbiology and meiobenthology”, wien. abstract book, 122–123. kuldvere, a. (1989): extraction of geological material with mineral acids for the determination of arsenic, antimony, bismuth, and selenium by hydride generation atomic absorption spectrometry.– analyst, 114/2, 125–131. lansdown, j.m., quay, p.d. & king, s.l. (1992): ch4 production via co2 reduction in a temperate bog: a source of 13c depleted ch4.– geochimica et cosmochimica acta, 56, 3493–3503. lewan, m.d. (1986): stable carbon isotopes of amorphous kerogens from phanerozoic sedimentary rocks.– geochimica et cosmochimica acta, 50, 1583–1591. lojen, s., ogrinc, n., dolenec, t., mihelčić, g. & branica, m. (1999): benthic fluxes of nutrients at the sediment/water interface in the peloid mud of makirina bay (croatia).– the 8th international symposium on the interactions between sediment and water, beijing. book of abstracts, 88. lojen, s., ogrinc, n., dolenec, t., mihelčić, g. & branica, m. (2000): decomposition of sedimentary organic matter in the recent sediment of makirina bay.– in: vlahović, i. & biondić, r. (eds.): 2. hrvatski geološki kongres (second croatian geological congress), cavtat–dubrovnik. zbornik radova (proceedings), 293– 297. mandić, v., novak, r., dürigl, t. & čepelak, r. (1969): peloid finding sites in the nin lagoon. results of exploration and medical significance.– jugosl. akad. znan. umjet., radovi instituta u zadru, 16–17, 753–786, zadar. masran, c. & pocock, s.a.j. (1981): the classification of plant-derived particulate organic matter in sedimentary rocks.– in: brooks, j. (ed.): organic maturation studies and fossil fuel exploration. academic press, london 145–175. mccrea, j.m. (1950): on the isotopic chemistry of carbonates and a paleotemperature scale.– j. chem. phys., 18, 549–857. 52 geologia croatica 58/1 mcnichol, a.p., lee, c. & druffel, e.r.m. (1991): carbon cycling in coastal sediments 2, an investigation of the sources of the σco2 to pore water using carbon isotopes.– in: baker, r.a. (ed.). organic substances and sediment in water. vol. 2, processes and analytical methods. lewis publishers inc., chelsea, michigan, 560 p. meischner, d. (1971): sediments as an environmental factor in benthic communities, especially with regard to the northern adriatic.– thalassia jugoslavica, 7, 217, zagreb. meischner, d. (1972): formation processes and dispersal patterns of the sediments along the istrian coast of the adriatic.– rapp. comm. int. mer méditerranée, 21, 222– 225. meischner, d. (1995): the coastal swamp of palu in istria – a mediterranean sea-level gauge for the late holocene.– in: vlahović, i., velić, i. & šparica, m. (eds.): 1. hrvatski geološki kongres – first croatian geological congress, opatija. abstracts, 60. mercone, d., thomson, j., croudace i.w. & troelstra s.r. (1999): a coupled natural immobilisation mechanism for mercury and selenium in deep-sea sediments.– geochimica et cosmochimica acta, 63, 1481– 1488. miko, s., šparica, ma. & prohić, e. (1998): some problems of selenium analysis in the organic-rich recent marine sediments (pelloids), pirovac bay, croatia.– 4. arbeit. des bereiches umwelt: erdwissenschaftliche aspekte des umweltschutzes, tagungsband, arsenal, ug’98, b5, vienna, 297–302. miko, s., mesić, s., prohić, e. & peh, z. (2003): trace elements distribution of lake vrana and topsoil of cres island, croatia.– natura croatica, 12/2, 93–111, zagreb. miko, s., šparica, m., koch, g., bačani, a., šparica-miko, m., čepelak, r., vreča, p., dolenec, t., bergant, s. & ibrahimpašić, h. (submitted): anthropogenic influence on trace element geochemistry of healing mud (peloid) from makirina cove (croatia).– environmental geochemistry and health. millero, f. (1995): thermodynamics of the carbon dioxide system in the oceans.– geochimica et cosmochimica acta, 59, 661. moldowan, j.m., sundararaman, p., salvatori, t., alajbeg, b., gjukić, b., lee, c.y. & demaison, g.j. (1992): source correlation and maturity assessment of select oils and rocks from the central adriatic basin (italy and yugoslavia).– in: moldowan, j.m., albrecht, p. & philp, r.p. (eds.): biological markers in sediments and petroleum. prentice-hall, new jersey, 370–401. novak, r. (1981): fizikalna svojstva peloida s posebnim osvrtom na muljeve jadranske obale i otoka.– zdravstvo, 11/2, 66–74, zagreb. oluić, m., bodrožić, d., mandić, v., novak, r. & čepelak, r. (1984): peloid karinskog mora i njegova primjena u zdravstvenoj zaštiti.– pomorski zbornik, 22, 437–465, split. oremland, r.s., miller, l.g. & whiticar, m.j. (1987): sources and flux of natural gases from mono lake, california.– geochimica et cosmochimica acta, 51, 2916–2929. orr, w.l. & gaines, a.g. (1973): observation on sulfate reduction and organic matter oxidation in the bottom waters of an estuarine basin: the upper basin of the pettaquamscutt river (rhode island).– advances in organic geochemistry, b, technic edition, paris, 89–101. parkhurst, d.l., thorstenson, d.c. & plummer, l.n. (1980): phreeqe – a computer program for chemical calculations.– u.s. geological survey, water resources inv., 80, 195 p. paul, j. (1970): sedimentologische untersuchungen eines küstennahen mediterranen schlammbodens (limski kanal, nördliche adria).– geol. rundsch., 60, 205–222. paul, j. (1971): long-time changes of a benthic community in a well aerated muddy bottom under quiet water condition, limski kanal, rovinj.– thalassia jugoslavica, 7, 231, zagreb. paul, j. & meischner, d. (1976): heavy metal analysis from sediments of the adriatic sea.– senckenbergiana marit., 8, 91–102. pravdić, v. & juračić, m. (1988): environmental capacity approach to the control of marine pollution. the case of copper in the krka river estuary.– chemistry and ecology, 3, 105–117. prohić, e. & juračić, m. (1984): sedimentation pattern and heavy metal distribution in peculiar karst estuary (eastern adriatic).– rapp. comm. int. mer méditerranée, 29/2, 143. prohić, e. & juračić, m. (1989): heavy metals in sediments – problems concerning determination of the anthropogenic influence. study in the krka river estuary, eastern adriatic coast, yugoslavia.– environmental geology and water science, 13, 145–151. prohić, e. & kniewald, g. (1987): heavy metal distribution in recent sediments of krka river estuary – an example of sequential extraction analysis.– marine chemistry, 22, 279–297. ranke, u. (1974): the sediments of the gulf of piran (northern adriatic sea).– senckenbergiana marit., 8, 23–60. raynaud, j.f., lugardon, b. & lacrampe-couloume, g. (1989): structure lamellaires et bacteries, composants essentiels de la matiere organique amorphe des roches meres.– bull. centres rech. explor. prod. elf aquitaine, 13/1, 1–21. robert, p. (1988): organic metamorphism and geothermal history.– elf aquitaine and d. reidl publ. company, 311 p. robbins, e.i., cuomo, m.c., haberyan, k.a., mudie, p.j., chen, y.y. & head, e. (1996): fecal pellets.– in: jansonius, j. & mcgregor, d.c. (eds.): palynology: principles and applications. american association of stratigraphic palynologists foundation, 3, 1085–1097. seibold, e. & wiegert, r. (1960): untersuchungen des zeitlichen ablaufs der sedimentation in malo jezero (mljet, adria) auf periodizitäten.– z. geophys., 26, 87– 104. 53šparica et al.: recent sediments of makirina cove (northern dalmatia, croatia)... sofer, z. & gat, j.r. (1975): the isotope composition of evaporating brines: effect on the isotopic activity ratio in saline solutions.– earth planet. sci. lett. 26, 179–186. sondi, i., juračić, m., prohić, e. & pravdić, v. (1994): particulates and environmental capacity for trace metals. a small river as a model for a land–sea transfer system: the raša river estuary.– science of the total environment, 155, 173–185. sondi, i., juračić, m. & pravdić, v. (1995): sedimentation in a disequilibrium river-dominated estuary. the raša river estuary (adriatic sea–croatia).– sedimentology, 42, 769–782. stach, e., mackowsky, m.th., teichmüller, m., taylor, g.h., chandra, d. & teichmüller, r. (1982): coal petrology.– gebr. bornträger, berlin–stuttgart, 535 p. steffen, d. & gorin, g.e. (1993): sedimentology of the organic matter in upper tithonian–berriasian deep-sea carbonates of south france.– in: katz, b.j. & pratt, l.m. (eds.): source rocks in a sequence stratigraphic framework. aapg studies in geology, 37, 49–67. stirn, j., avcin, a., cencelj, j., dorer, m., gomiscek, s., kveder, s., malej, a., meischner, d., nozina, i., paul, j. & tusnik, p. (1974): pollution problems of the adriatic sea: an interdisciplinary approach.– rev. intern. oceanogr. med., 35/36, 21–78. stumm, w. & morgan, j.j. (1996): aquatic chemistry.– wiley–interscience, new york, 1022 p. surić, m., juračić, m., horvatinčić, n. & krajcar bronić, i. (2005): late pleistocene–holocene sea-level rise and the pattern of coastal karst inundation – records from submerged speleothems along the eastern adriatic coast (croatia).– marine geology, 214/1–3, 163–175. šegota, t. (1982): sea level position and the vertical movement of the adriatic sea bottom from riss–würm interglacial to recent.– geol. vjesnik, 35, 93–109. šegota, t. & filipčić, a. (1991): archaeologic and geologic proofs for holocene sea level position on the east adriatic littoral.– rad hazu, 458, raz. prir. znan., 25, 149–172, zagreb. šparica, m., belak, m. & crnko, j. (1995): recentni sedimenti uvale makirina u pirovačkom zaljevu [recent sediments of the makirina cove in the pirovac bay – in croatian].– in: vlahović, i., velić, i. & šparica, m. (eds.): 1. hrvatski geološki kongres (first croatian geological congress), zbornik radova (proceedings), 2, 595–600. tabatabai, m.a. (1974): a rapid method for determination of sulfate in water samples.– environ. lett., 7, 237. tissot, b.p. & welte, d.h. (1984): petroleum formation and occurrence.– springer verlag, berlin, 699 p. tribovillard, n.p. & gorin, g.e. (1991): organic facies of the early albian niveau paquier, a key black shales horizon of the marnes bleues formation in the vocontian through (subalpine ranges, france).– palaeogeogr., palaeoclimatol., palaeoecol., 85, 227–237. tyler, m.a., coats, d.w. & anderson, d.m. (1982): encystment in a dynamic environment: deposition of dinoflagellate cysts by a frontal convergence.– mar. ecol. prog. ser., 7, 126–178. tyson, r.v. (1987): the genesis and palynofacies characteristics of marine petroleum source rocks.– in: brooks, a. & fleet, a.j. (eds.): marine petroleum source rocks. geol. soc. spec. publ., 26, 46–67. tyson, r.v. (1989): late jurassic palynofacies trends, piper and kimmeridge clay formation, uk onshore and northern north sea.– in: batten, d.j. & keen, m.c. (eds.): northwest european micropalaeontology and palynology. brit. micropal. soc. ser., 9, 135–172. tyson, r.v. (1995): sedimentary organic matter. organic facies and palynofacies.– chapman & hall, london, 615 p. tyson, r.v. & funnell, b.m. (1987): european cretaceous shoreline, stage by stage.– palaeogeogr., palaeoclimatol., palaeoecol., 59, 69–91. uffenorde, h. (1971): seasonal and aseasonal changes in marine benthic ostracode populations, limski kanal, rovinj.– thalassia jugoslavica, 7, 417, zagreb. uffenorde, h. (1975): dynamics in recent marine benthic ostracode assemblages in the limski kanal (northern adriatic sea).– bull. amer. paleont., 65, 147–165. vaniček, v., juračić, m., bajraktarević, z. & ćosović, v. (2000): benthic foraminiferal assemblages in a restricted environment – an example from mljet lakes (adriatic sea, croatia).– geol. croatica, 53/2, 269–279. van waveren, i. & visscher, h. (1994): analysis of the composition and selective preservation of organic matter in surficial deep-sea sediments from a high-productivity area (banda sea, indonesia).– palaeogeogr., palaeoclimatol., palaeoecol., 112, 85–111. vdović, n. & juračić, m. (1993): sedimentological and geochemical characteristics of the northern and central adriatic sediments.– geol. croatica, 46/1, 157–163. viličić, d. (1989): phytoplankton population density and volume as indicators of eutrophication in the eastern part of the adriatic sea.– hydrobiologia, 174, 117–132. viličić, d., jasprica, n., carić, m. & burić, z. (1998): taxonomic composition and seasonal distribution of microphytoplankton in mali ston bay (eastern adriatic).– acta bot. croat., 57, 29–48, zagreb. vlahović, i., tišljar, j., fuček, l., oštrić, n., prtoljan, b., velić, i. & matičec, d. (2002): the origin and importance of the dolomite–limestone breccia between the lower and upper cretaceous deposits of the adriatic carbonate platform: an example from ćićarija mt. (istria, croatia).– geol. croatica, 55/1, 45–55. vreča, p. (1998): izotopske in geokemične značilnosti recentnega sedimenta iz zaliva makirina, otok murter (srednji jadran) (isotopic characteristics of the recent sediment of makirina bay, murter sea (central adriatic).– unpublished msc thesis (in slovenian with english abstract), university of ljubljana, 99 p. vreča, p., dolenec, t., šparica, m. & mišić, m. (1999): geokemične raziskave zdravilnega mulja iz zaliva 54 geologia croatica 58/1 makirina (srednji jadran) (geochemical investigations of healing mud from makirina bay (central adriatic)).– rmz–materials and geoenvironments, 46, 641–650, ljubljana. wang, w., fisher, n.s. & luoma, s.n. (1996): kinetic determinations of trace element bioaccumulation in the mussel mytilus edulis.– marine ecology progress series, 140, 91–113. wunsam, s., schmidt, r. & müller, j. (1999): holocene lake development of two dalmatian lagoons (malo and veliko jezero, isle of mljet) in respect to changes in adriatic sea level and climate.– palaeogeo., palaeoclim., palaeoecol., 146, 251–281. zehr, j.p. & oremland, r.s. (1987). reduction of selenate to selenide by sulfate-respiring bacteria: experiments with cell suspensions and estuarine sediments.– appl. environ. microbiol., 53, 1365–1369. manuscript received januar 15, 2004. revised manuscript accepted april 15, 2005. plate i mineralogical composition of the 0.09–0.16 mm fraction of the insoluble residue of the makirina cove sediments 1 pyrite, 160x, n-. agglomeration of authigenic pyrite. 2 chert, 160x, n+. particles of chert rock. 3 feldspar, 160x, n+. hypidiomorphic and semirounded quartz grain. 4 quartz, 160x, n+. asymmetric and semiangular quartz grain. 5, 6 glaucophane, 170x, n-. fig. 5) vibration direction of blue pleochroism; fig. 6) vibration direction of violet pleochroism. 7 amphibole, 170x, n-. crumbled, semiangular amphibole with green pleochroism. 8 pyroxene, 160x, n-. prismatic green pyroxene, angular, may also be volcanic in origin. 9 garnet, 160x, n-. brownish garnet, semiangular, asymmetric in shape. 10 garnet, 160x, n-. pale-pinky garnet of an asymmetric shape. 11 zircon, 160x, n-. rounded to very well rounded zircon grain. 12 tourmaline, 160x, n-. semirounded tourmaline. 13 zircon, 160x, n-. rounded zircon grain. 14 garnet, 160x, n-. a colourless grain of garnet, angular and asymmetric in shape. 15 zircon, 160x, n-. these features of a zircon grain indicate a volcanic origin. 16 garnet, 160x, n-. a colourless garnet, semiangular and asymmetric in shape. 17 zircon, 160x, n-. idiomorphic, angular to semirounded crystal of zircon. 18 zircon, 500x, n-. zircon is prismatically elongated, crumbled, completely angular, idiomorphic with volatile inclusions and a thin tube inclusion which indicates a volcanic origin. 55šparica et al. plate i 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 56 geologia croatica 58/1 plate ii distribution of sio2, al2o3, fe2o3, feo, mno, mgo, cao, na2o, k2o and tio2 in the surficial sediments of makirina cove 57šparica et al. plate ii si02(%) mno (ii) coo (%) •• u •• .. •• .. •• .. •• .. •• .. 1.1' ... •• • ~ u ~ u k,o(%) ai.o.(%) foo (ii) mgo (ii) n'20 (ii) tlo.(%) .u " u u u u .. , u u .. u u u u u u , .. .. u .. .. •• •• .. u • ,. ,. ,. ,. u u u u u u u u 58 geologia croatica 58/1 plate iii distribution of p2o5, ba, sr, y, zr, v, cu, pb, zn and ni in the surficial sediments of makirina cove 59šparica et al. plate iii .. ". , . ... , . . ,. , . . , ' . '. ~ '. '. ~ ,. ,. ,. ,. ~ ,. ... ~ ... ,. ~ ,. p,o. (%) ba (ppm) ~ • ~ • ~ • -• .. • ~ • '" .. '" .. ... .. '" sr(ppm) y (ppm) ,. ,. • • • • • • • • • • • .. • zr (ppm) y (ppm) • • • • • • • • • • • • • • • • • • • • • • • cu (ppm) pb (ppm) zn (ppm) ni (ppm) 60 geologia croatica 58/1 plate iv distribution of as, br, cs, hf, mo, rb, sb, sc, th and u in the surficial sediments of makirina cove 61šparica et al. plate iv • -• • -• -• -• -• -• -• -• • -• -• •• • •• .. •• • •• •• • • • as (ppm) br(ppm) " u u u u u u u u u " u u u " " " " " " c. (ppm) hf(ppm) • •• • •• • •• • •• • ... • ... • •• • •• • • • • • • • • • • • • • • • • • • • • • • • • • • mo (ppm) rb (ppm) " •• .u •• •• .. " •• u " 1.11 ... u •• • -" " -u -" u -u u " ~ u -sb (ppm) so (ppm) ~ .. • u ... • u .. • ~ " , • u u • u • u " • " " • " • u " th (ppm) u (ppm) 62 geologia croatica 58/1 plate v distribution of la, ce, nd, sm, eu, yb, lu, s and c in the surficial sediments of makirina cove 63šparica et al. plate v • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • l. (ppm) c. (ppm) u u • u u u • u u u u nd (ppm) sm(ppm) ,. " u ,. u " u ,. u " .. ,. ,. .. '. " " 1.11 , . ... ... ,. " , " ~ ., u ~ " eu (ppm) yb (ppm) ., • --~ -----.' • -~ = -----lu (ppm) ,. ,. " ,. ,. ,. '. " ,. ,. '.10 " " ,. ,.,. , ... -u '. -, u ~ •• ., ., -~ u -., u -.. u -• ., -• ... s!"") c(%) 64 geologia croatica 58/1 plate vi the most characteristic plants in the area of makirina and pirovac bay 1 arundo donax 2 schoenus nigricans 3 juncus maritimus 4 arthrocnemum glaucum 5 limonium serotinum 6 juncus acutus 7 helicrysum italicum 8 codium bursa 65šparica et al. plate vi 1 2 3 4 5 6 7 8 66 geologia croatica 58/1 plate vii some of the most characteristic molluscs of makirina cove 1 laevicardium oblongum 2 nuculana fragilis 3, 4 gourmya vulgata 5 monodonta turbinata 6 coralline algal crusts around different mollusc shells. 67šparica et al. plate vii 1 2 43 5 6 68 geologia croatica 58/1 plate viii 1 cuticular tissue with framboidal pyrite inclusions (fpi). 2 pollen (bisaccate, conifer) with fpis. 3 organic walled dinoflagellate cyst (spiniferites type) with fpis. 4 foraminiferal test lining with fpis. 5 tintinnid chitinous lorica with fpis. 6 crustacean chitinous skeleton with fpis. 7 scolecodont and granular to spongy amorphous organic matter (aom) with fpis. 8 disseminated, granular to spongy aom with fpis, fragments of faecal pellets, fibrous to membranous strucureless organic matter, algal tissue and small globules of waxes/resins; transmitted white light. 9 idem; incident blue light (note fluorescence). 1–9 sample m–i/4; 1, 4–9 – 400x; 2, 3 – 800x. 69šparica et al. plate viii 1 2 3 4 5 6 7 8 9 70 geologia croatica 58/1 plate ix 1 disseminated, granular, aggregated granular to spongy aom with fpis, fragments of faecal pellets, membranous, fibrous to filamentous structureless organic matter, ligno-cellulosic tissue, algal tissue and small globules of waxes/resins; transmitted white light. 2 idem; incident blue light (note fluorescence). 3 granular to spongy aom with fpis and ligno-cellulosic tissue; transmitted white light. 4 idem; incident blue light (note fluorescence). 1, 2: sample m–i/4; 3, 4: sample m–i/10; 1–4 – 400x. 71šparica et al. plate ix 1 2 43 72 geologia croatica 58/1 geologia croatica 45 177 -181 zagreb 1992 inmemoriam dr. teofil slišković (1926 1991) dr. teofil slišković was born in the small village of tm, near lištica, in western hercegovina. he studied geology and paleontology at the university of zagreb where he obtained his b.sc. in 1955, m.sc. in 1964, and d.sc. degree in 1968. after obtaining his b.sc. he was appointed custodian at the geological department of the national museum of bosnia and hercegovina in sarajevo where he stayed until his un timely death. for many years he was head of the museum geological department. teofil slišković was both an active field geologist and a care­ fuj museum curator. his scientific bibliography includes more than 100 titles, a part of which (hopefully a larger one) we managed to compile in the enclosed bibliography. while he profusely published on stratigraphy and paleontology of the whole bosnia and hercegovina, ranging in age from the paleozoic to the quatemary, he most em­ phatically studied cretaceous strata and a"sociated rudist fauna. he established several new taxa (species and genera) of rudists and became one of the few world-wide recognized experts on these fascinating bivalves, as well as in cretaceous stratigraphy and paleogeography. his results were widely recognized by foreign colleagues and quoted in international publications, including the r.c. moore's "treatise" (though published as early as 1969). teofil slišković was spared of brutal destruction of his native cou.,try and trag ic destiny of its people, but if he were still alive,he would certainly not have given up hope of a new, peaceful future for his country. just as we don't. dana 5.11.1991. umro je u zagrebu, nakon duže bolesti, dr. teofil slišković, znanstveni savjetnik i dugogodišnji voditelj geološkog odjela zemaljskog muzeja bosne i hercegovip..e u sarajevu. dr. teofil slišković rođen je l. :s. 1926. u selu trn kraj lištice u zapadnoj hercegovini. klasično obrazovanje stekao je u poznatoj franjevačkoj klasičnoj gimnaziji na širokom brijegu, a geologiju je studirao na prirodoslovno­ matematičkom fakultetu sveučilišta u zagreb~. tu je diplomirao 1955. god., završio postdiplomski studij i magistrirao 1964. god. s temom o stratigrafiji gornje krede planine velež i podveležja s osobitim osvrtom na rudistnu faunu, i doktorirao 1968. god., obranivši disertaciju pod naslovom: "biostratigrafija gornje krede južne hercegovine". nakon diplomiranja prvo je nekoliko godina radio u geološkom zavodu u sarajevu, gdje je uspješno vodio prvu ekipu za izradu ogk u bosni i hercegovini. nakon toga postao je kustosom zemaljskog muzeja u sarajevu, gdje je djelovao do kraja života, postavši ubrzo voditeljem geološkog odjela, a zadnjih dvadesetak godina u zvanju znanstvenog savjetnika. područje znanstvenog djelovanja t. sliškovića bila je, u prvom redu, stratigrafija i paleontologija. iz tog područja objavio je stotinjak radova, većinom u uglednom glasniku zemaljskog muzeja bosne i hercegovine i sarajevskom geološkom glasniku, ali i drugdje: u izdanjima hazu, različitim kongresnim publikacijama i zbornicima, pa i u međunarodnim časopisima. s trati grafiju je zahvaćao veoma široko: vremenski od paleozoika, preko trijasa, jure i krede doneo gena i kvartara, a prostorno u skladu sa znanstvenim kompetencijama muzeja čitavo područje bosne i hercegovine, koju je kao geolog prošao uzduž i poprijeko. ipak, područje njegovog posebnog interesa i, čak bih rekao, ljubavi bilo je doba krede i kredne naslage (što se vidi po naslovima njegovih kvalifikacijskih i velikom broju ostalih radova), i posebno rudistna fauna iz tih naslaga. bio je jedan od malobrojnih svjetski priznatih specijalista za tu osebujnu skupinu izumrlih školjkaša, od kojih je za muzej sakupio oko 5.000 primjeraka. proučavanjem biostratigrafije krednih naslaga i u njima sadržanih fosilnih rudistnih zajednica postavio je nekoliko novih taksona rudista (vrsta i rodova), od kojih je većina prihvaćena i potvrđena od kasnijih 178 istraživača kao priznata i validna. njegovi rezultati citirani su u međunarodnim publikacijama uključivši i nezaobilazni "treatise" (premda tiskan još 1969. god.). poznavanje stratigrafije i paleogeografije krede i razdoblja na prijelazu kreda-paleogen omogućilo muje da značajno doprinese i geologiji boksita i boksitnih ležišta. no, osim krede i rudis takojoj tematici je posvećeno oko tridesetak njegovih znanstvenih radova bavio se, pretežno u suradnji s drugim autorima, i lijaskim litiotidima (od kojih je sakupio oko 200 primjeraka), slatkovodnim mekušcima iz neo genskih bazena bosne i hercegovine (oko l 000 primjeraka), osobito kongerijama i klivunelidama, pa mikrofosilnim zajednicama iz mezozojskih karbonatnih naslaga te fosilnim ostacima neo genskih i pleistocenskih kralježnjaka koje je otkrio na nekoliko do tada nepoznatih nalazišta u bosni i hercegovini. o njegovom nesumnjivom znanstvenom doprinosu poznavanju geologije i paleontologije · bosne i hercegovine svjedoči i činjenica da je bio stalni član komisije za mineralne sirovine akademije nauka bosne i hercegovine, član societe geologique de france, palaontologische gesellschaft, hrvatskog geološkog društva te razumije se, geološkog, speleoškog i muzejskog društva bih. kao što se vidi iz njegove znanstvene biografije i popisa radova, do kraja života održavao je prisne veze i aktivnu suradnju s geološko­ paleontološkim zavodom prirodoslovno-matematičkog fakulteta u zagrebu, geološkim odjelom hrvatskog prirodoslovnog muzeja i zavodom za geologiju i paleontologiju kvartara hazu. bio je, dakle, i do kraja ostao đak zagrebačke geološke i paleontološke škole u punom smislu riječi i kao takav bio je u svom djelovanju lučonoša i promicatelj naše, hrvatske prirodoslovne i znanstvene misli u sredini u kojoj je živio i radio. kao muzealac i nasljednik uglednog bečkog geologa friedricha katzera, koji je također više desetljeća djelovao u istom muzeju, mnogo je učinio i za zemaljski muzej u sarajevu, tu tradicionalno uglednu znanstvenu ustanovu u kojoj je djelovao čitav svoj radni vijek, nastojeći oko povećanja i sređivanja geološkog i paleontološkog dijela muzejskog fundusa, uređenja novog stalnog muzejskog postava "svijet geološke prošlosti bosne i hercegovine", obogaćivanja muzejske biblioteke vrijednim inozemnim publikacijama, i dr. kao čovjek, dr. teofil slišković objedinjavao je osobine koje se rijetko susreću u jednoj osobi: bio je naime priznati stručnjak i cijenjeni znanstvenik, a ujedno i dobar drug, čovjek i prijatelj. skroman i .odmjeren u nastupu, iskren i srdačan u ophođenju, sistematičan i ustrajan pa i strog i kritičan u znanstvenom radu. bio je uvjereni borac za znanstvenu istinu. ova posljednja osobina donijela mu je i nesklonost pojedinih kolega, osobito nekih koji su po "partijskoj liniji" bili došli na rukovodeće položaje, jer je nekoliko puta opravdano i oštro kritizirao njihovu površnost. volio je svoju hercegovinu pa i cijelu bih, kao i sarajevo i svoj zemaljski muzej. sudbina ga je poštedjela geologia croatica 45 od toga da s ogorčenjem i uz životnu opasnost doživljava divljačko razaranje svoje domovine i sarajeva i ubijanje njihovih žitelja. ti tragični događaji spriječili su da na vječni počinak bude položen u gradu kojemu je darovao čitav svoj radni vijek. ali i u zagrebu, gdje je sahranjen na groblju miroševac, od njega su se, uz rodbinu, oprostili i mnogobrojni prijatelji, kolege i suradnici, koji se uzdaju u budućnost i obnovu njegove domovine, u što bi, da je živ, i teofil slišković sigurno čvrsto vjerovao. zahvaljujem gospođi ankici slišković, udovici pokojnog teofila, i gospodinu peri sliškoviću, bratu, na razgovorima i podacima o životu pokojnog teofila sliškovića. · ivan gušić bibliografija važnijih rado v a dr. teofila sliškovića sastavila blanka cvetko l. das mesozoikum und palaogen zwischen li vanjsko, duvanjsko und šujičko polje. bull. sci. cons. acad. yougosl., 5(3, zagreb,l960. 2.-, raić, vid & papeš, josip: tektonski i paleogeografski odnosi južne i jugoistočne hercegovine.referati 5. sav. geol jugosl., l, 8392, beograd,l962. 3. , papeš, josip, raić, vid & luburić, pero: o stratigrafiji i tektonici južne hercegovine. geol. glasnik, 6, 111-140, sarajevo, 1962. 4. , raić, vid & papeš, josip: tektonski i paleogeo­ grafski odnosi južne i jugoistočne hercegovine. 5 kongr. geol. jugosl., l, beograd, 1962. 5. prilog poznavanju rudistne faune bosne i hercegovine uzosvrtnadosadašnjaistraživanja. -glasnikzemalj. muzeja b. i h., prir.nauke, (n.s.), 2, 5-29, sarajevo, 1963. 6. stratigraphisch-palaontologische untersuchungen der kreideschichten des velež-gebirge und des pod­ velež. -bull. sci.cons. acad. yougosl., 8/3-4, zagreb, 1963. 7. hippurites (v accinites) ultimus milanović iz mastrihta buduželjajužno od vareša.geol. glasnik, 9, 1520, sarajevo, 1964. 8. & luburić, pero: stratigraphische lage des bauxit in der hercegovina und in sw bosnien. bull. sci. cons. acad. yougosl., 9/1-2, zagreb, 1964. 9. malez, mirko & slišković, teofil: neuefundorte tertiarer wirbeltiere in bosnien und herzegowina. -bull. sci. cons. acad. yougosl., 9/1-2, 2-4,zagreb, 1964. 10. papeš, josip, luburić, pero, slišković, teofil & raić, vid: geološki odnosi šire okolice livna, duvna i glamoča u jugozapadnoj bosni. geol. glasnik, 9, 87-122, sarajevo, 1964. ll. nova nalazišta vapnenca s globotrunkanama u hercegovini i jugozapadnoj bosni. -glasnik ze malj. in memoriam: t. slišković muzeja b. i h., prir. nauke, (n.s.), 3-4, 35-40, sarajevo, 1964/65. 12. malez, mirko & slišković, teofil: o novim nalazima vrste dinotherium bavaricum v. meyer uugljenokopu repovica kod konjica. glasnik zemalj. muzeja b. i h.,prir. nauke, (n.s.), j/4, 7: 33, sarajevo, 1964/65. 13. nekoliko vrsta roda neocaprina iz gomjokrednih naslaga velež-planine. acta geol. jazu, 5, zagreb, 1965. 14. uber das stratigraphische verhaltnis zwischen der oberkreideund liburnischen schichten auf dem gebiet von metkovi) und čapljina -bull. sci. cons. acad. yougosl., (a), 10/11, zagreb, 1965. 15. die biostratigraphie des juras un teren kreide des velež gebirge und podveležje. -bull. sci. cons. acad. yougosl., (a), 10/11, zagreb, 1965. 16. katzeria hercegovinaensis n. gen. n. sp. aus obersenonischen ablagerungen der sudherzegovina. -bull. sci. acad. yougosl., (a), 11n-9, zagreb, 1966. 17. zwei neue arten der gatung lchtyosarcolites aus der oberkreideablagerungen der sudherzegovina. -bull. sci. acad. yougosl., (a), 11n-9, zagreb, 1966. 18. polšak, ante & slišković, teofil: granica donja­ gornja kreda i biostratigrafija gornje krede u vanjskom pojasu dinarida. referati 6. sav. geol. jugosl., l, 327-354, ohrid, 1966. 19. hippurites (vaccinites) chaperi douville iz senonskih naslaga okolice imotskog. -glasnik zemalj. muzeja b. i h., prir. nauke, (n.s.), 6, 23-33, sarajevo, 1967. 20. trubeua, fabijan & slišković, teofil: the stratigraphic position and mineralogical compo­ sition of the igneous rocks of sutjeska national park.bull. sci. cons. acad.yougosl., (a), 12/ 7-8, zagreb, 1967. 21. vrsta hippurites (vaccinites) braciensis sladi}­ trifunović iz hercegovine i njezin stratigrafski . položaj. -glasnik zemalj.muzeja b. i h., prir. nauke, (n.s.), 7, 123-137, sarajevo, 1968. 22. biostratigrafija gornje krede južne hercegovine. glasnik zemalj. muzeja b. i h., prir. nauke, (n.s.), 7, 5-66 str., sarajevo, 1968. 23. novi rudisti hercegovine. glasnik zemalj. muzeja b. i h., 7, prir. nauke, (n.s.), 69-95, sarajevo, 1968. 24.& raić, vid: razvoj i paleogeografija paleogena u vanjskom pojasu dinarida bosne i hercegovine. -prvi kol. o geol. dinaridov,l,149-154,ljubljana, !968. 25.& gušić, ivan: starost naslaga s fosilnim ribama · taleže i huma kod trebinja. glasnik zemalj. muzeja b. i h., prir. nauke, (n.s.), 8, 47-54, sara jeve, 1969. 26. kochansky-devide, vanda & slišković, t emil: gornjopermski mikrofosili han orahovice i šuljaca u bosni s osobitim obzirom na algu permocalculus fragilis. geol. vjesnik, 22, 105110, zagreb, 1969. 179 27. neke vrste malo poznatog rudistnog roda apulites iz gomjosenonskih naslaga bosne i hercegovine. -glasnik zemalj.muzeja b. i h., prir. nauke, (n.s.), 9, 13-21, sarajevo, 1970. 28. die stratigraphische lage der schichten mit pachyophiidae aus selište bei bileća (ostherzegowina). -bull. sci. cons. acad. yougosl., (a), 15/11-12, zagreb, 1970. 29. biostratigrafske karakteristike mlađeg senona u jugozapadnoj hercegovini.glasnikzemalj. muzeja b. i h., prir. nauke, (n.s.), 10, 3-18, sarajevo, 1971. 30. novija istraživanja krednih naslaga istočne bosne. · glasnik zemalj. muzeja b. i h., prir. nauke, (n.s.), 10, 19-27, sarajevo,l971. 31. biostratigaphie du cretace superieur de 1-herzegovine meridionale. wiss. mitteil. bosn. herzegow. landesmus., (c).,l, 13-71, sarajevo, 1971. 32. les nouveaux rudistes de 1--herzegovine. wiss. mitteil. bosn.herzegow. landesmus., (c), l, 73-103, sarajevo, 1971. 33. presence de l'espece hippurites (vaccinites) braciensis sladić-trifunović en herzegovine medionale et sa position stratigraphique. wiss. mitteil. bosn. herzegow.landesmus.,(c), 1,131-147,sarajevo, 1971. 34. die nerineiden der oberjura von sudwestbosnien. bull. sci. cons. acad. yougosl., (a), 17/11-12, zagreb, 1972. 35. & gušić, ivan: das alter der ablagerungen mit fossilen fischen von taleža und hum bei trebinje, herzegowina.wiss. mitteil. bosn.herzegow. landesmus., (c), 2, 49-56, sarajevo, 1972. 36. kochansky-devide, vanda & slišković, teofil: revizija roda clivunella katzer, 1918 i delminiella n. gen. (gastropoda). geol. glasnik, 16,47-70, sarajevo, 1972. 37. malez, mirko, ruka vina, darko & slišković, teofil: eine neue palaontologische und palaolitische fundstelle in westbosnien.bull. sci. cons. acad. yougosl., (a), 17n~8. 229231, zagreb, 1972. 38. sur quelques especes du genre apulites provenant des couches du senonien superieur de la bosnie et herzegovine. wiss. mitteil. bosn.herzegow. landesmus., (c), 3, 13-20, sarajevo, 1973. 39.& gušić, ivan: o stratigrafskom položaju boksita i razvoju krede u istočnoj bosni. 2. jugosl. sim p. istraž. eksploat. boksita, j o str., tuzla, 1973. 40. & milan, ante: biostratigrafski odnosi .nalmau jugozapadnoj bosni i istočnoj hercegovini. geol. vjesnik, 26, 325-330, zagreb, 1973. 41. papeš, josip, trubeua, fabijan & slišković, teofil: effet de la repartition terre/mer sur la for­ mation des gisements de bauxite en bosnie herzegovine, yougoslavie.icsoba, 3. congr. intern., nice, 1973. 42. rudists of the senonian in the environs of višegrad in eastern bosnia.bull. sci. cons. acad. yougosl., (a), 19/5-6, zagreb,1974. 180 43. praelapeirouseia wiontzek i milovanov\cia polšak iz gornjokrednih naslaga okolice višegrada u istočnoj bosni.glasnikzemalj.muzeja b .i h., prir. nauke, (n.s.), 13, 23-51, sarajevo, 1974. 44. malez, mirl.."\j, ruka vina, darko, slisković, teofil &·kapel, ante: two new sites of pleis­ tocene fauna and of the palaeolithic in bosnia. bull. sci. cons. acad. yougosl., (a), 19/3-4, 8083, zagreb, 1974. 45. rudist fauna ofvlaši} mountain in the central bosnia. -bull. sci.cons. yougosl., (a), 20/5-6, zagreb, 1975. 46. dvije nove vrste rudistnog roda petkovicia kuhn i pejović iz gornjosenonskih naslaga vlašić-planine u središnjoj bosni. glasnik zemalj. muzeja b. i h., prir. nauke, (n.s.), 14, 127-132,sarajevo, 1975. 4 7. caracteristique biostratigraphiques du senonien terminal dans 1-herzegovine sud-occidentale. wiss. mitteil. bosn.herzegow.landesmus., (c), 4/5, 41-48, sarajevo, 1974/75. 48. recherches plus recentes sur les couches cretacees de la bosnie orientale. wiss. mitteil. bosn. herzegow. landesmus., (c), 4/5, 49-58, sarajevo, 1974/75. 49. praelapeirouseia wiontzek et milovanovicia polšak provenant des couches du cretace superieur des environs de višegrad en bosnie orientale. wiss. mitteil. bosn.herzegow. landesmus., (c), 4/5, 59-89, sarajevo, 1974/75. 50. two new gorjanovicijas from the northwest slopes of vlašić mountain in the central bosnia.bull. sci. cons. acad. yugoslav., (a), 20/11-12,351352, zagreb, 1975. 51. uber das stratigraphische verhaltnis zwischen den oberkreideund libumischen schichten auf dem gebi et von metkovi} und čapljina -bull. sci. cons. acad. yougosl., (a), 10/11, 373-374, zagreb, 1975. 52. bibliografija katzerovih radova i članaka o katzeru. geol. glasnik, 20, 195-208, sarajevo, 1975. 53. friedrich katzer kao paleontolog. geol. glasnik, 20, 153-162, sarajevo, 1975. 54. friedrich katzer, zaslužni istraživač fosilne flore i faune bosne i hercegovine. -biološki list, 24, 54-56, sarajevo, 1975. 55. deux especes nouvelles de rudistes du genre petkovicia kuhn et pejović provenant des couches du senonien superieur de la montagne de vlašić en bosnie cen:rale. wiss. mitteil. bosn. herzegow. landesmus., (c), 6, 59-63, sarajevo, 1976. 56. gusić, ivan & slisković, teofil: mikropaleonto­ loške odlike krede istočne bosne.8. kongr. geol. jugoslav., bled (1974), 2, 91-97, ljubljana, 1976. 57. malez, mirko & slisković, teofil: starost nekih naslaga ugljena u tercijaru bosne i hercegovine na osnovi nalaza vertebrata.geol. glasnik, 21, 39-56, sarajevo,l976. 58. geological and mineralogical pecularities of baux­ ite deposits in bosnia and herzegovina (yugoslavia). geologia croatica 45 cmsicsoba, conference,kingston (jamaica), 1977. 59. raić, vid, papes, josip, behlilović, salih, crnolatac, ivan,mojićević, mladen, ranković, milan, slisković, teofil, đorđ ević,borivoje, golo, branislav, ahac, anto, luburić, petar & marić,ljubomir: osnovna geološka karta sfrj. l: 100 000. list metković. geoinženjering oour inst geol. sarajevo (1971 ), inst geol.istraž. zagreb, sav. geol. zavod, beograd, 1977. 60. rudisti gornje krede bosne i njihovo biostratigrafsko značenje.zbornik radova 9. kongr. geol. jugosl., 56-62, sarajevo, 1978. 61. pokušaj paralelizacije naslaga kopnenog miocena s klivunelidama u bosni i hercegovini. zbornik radova 9. kongr. geol. jugosl., 135-138, sarajevo, 1978. • 62. o litiotidima hercegovine i zapadne bosne. -glasnik zemalj. muzeja b. i h., prir. nauke,(n.s.), 17,2346, sarajevo, 1978. 63. -, pavlovec, rajko & drobne, katica: stariji paleogen u južnoj hercegovini. -zbornik radova 9. kongr.geol. jugosl., 125-128, sarajevo, 1978. 64. kochansky-devide, vanda & slisković, teofil: miocenske kongerije hrvatske, bosne i hercegovine. -palaeont.jugosl., 19, l-98,zagreb, 1978. 65. malez, mirko, ruka vina, darko & slisković, teofil: kvartargeološki i paleontološki odnosi u pećinirastušikod teslića.glasnikzemalj. muzeja b. i h., prir. nauke, (n.s.), 16 (1978), 5-22, sarajevo, 1978. 66. stratigrafska i paleontološka istraživanja pe} inskih naslaga u bosni i hercegovini. naš krš, 5/6, sarajevo, 1979. 67. po ls ak, ante, ba ller, vera & slisković, teofil: stratigraphie du cretace superieur de la" plateforme carbonates" dans ranee. en: les facies de plateforme du cretace dans le domaine mesogeen. 26e congr. intern. resumes, vol. l (sec. 1-5), str. 275, paris, 1980. 68. kochansky-devide, vanda & slisković, teofil: mlađe miocenske kongerije livanjskog, duvanjskog i kupreškog polja u jugozapadnoj bosni i radova u hercegovini. palaeont. jugosl., 25, 1-25, zagreb, 1980/81. 69. o strati grafskim i paleogeografskim odnosima mlađeg senona i paleocena u bosni i hercegovini. simp. o problemih danija v jugoslaviji. zbornik referatov, 2, 47-60, ljubljana, 1981. 70. ihtiosarkoliti (hippuritacea) hercegovine i zapedne bosne. razvoj i vertikalno prostranstvo. -zbornik radova 10. kongr. geol.jugosl., 219-225; budva, 1982. 71. new radiolitidae ( hippuritacea) from the cretaceous deposits of bosnia and herzegovina. glasnik zemalj. muzeja b. i h., prir.nauke, (n.s.), 21, 1in memoriam: t. slišković 19, sarajevo, 1982. 72. polsak, ante, bauer, vera & slišković, teofil: stratigraphie du cretace superieur de la platforme carbonatee dans les dinarides extemes. -cretaceous res., 3, 2-9, 2 sl.,london, 1982. 73. rezultati novijih istraživanja biostratigrafije ipaleogeografskih odnosa mlađeg senona u okolici stoca (hercegovina). -glasnik zemalj. muzeja b. i h., prir. nauke,(n.s.), 22, l-18, sarajevo, 1983. 74. ichthyosarcolites monocarinatus major n. subsp. (hippuritacea) iz cenomanskih naslaga velež planine (hercegovina). -glasnik zemalj. muzeja b. i h., prir. nauke, (n.s.), 22, 19-26, sarajevo, 1983. 75. gorjanovicia vlasicensis new name for gorjanovicia polsaki slišković 1982.glasnikzemalj. muzeja b. i h., prir. nauke, (n.s.), 22, 27-28, sarajevo, 1983. 76. & trubeua, fabijan: bosna i hercegovina. geološka građa i petrografski sastav.enciklopedija jugosl., ii izd.,jugsl.leksikogr. zavod, 2, 111-114, zagreb, 1983. 77. kreda. -u: geologija bosne i hercegovine 2 mezozojske periode,229-277, sarajevo, 1984. 78. eoradiolites jovanovici n. sp. iz donjokrednih naslaga istočne bosne. -radovi akad. nauka b. i h., 75, odjelj. tehn. nauka, 5,sarajevo, 1984. 79. some new rudists (hippuritacea) from the senonian deposits in the vicinity of višegrad in eastern bosnia. glasnikzemalj. muzeja b. i h., prir. nauke, (n.s.), 23, 195-211, sarajevo, 1984. 80. o nalazištima rudista u gornjem toku rijeke ugra (središnja bosna) i njihovom biostratigrafskom značenju. glasnik zemalj.muzeja b. i h., prir. nauke, (n.s.), 23, 213-222, sarajevo, 1984. 81. malez, mirko & slišković, teofil: kvartarno­ geološki i paleontološki odnosi u spilji megari na b jelašnici. -zbornik predavanja 9. jugosl. speleol. . kongres, karlovac (1984}, 697-710, zagreb, 1984. 82. masse, jean pierre, skel ton, peter & slišković, teofil: glossomyophorus costatus nov. gen. nov. sp., rodiste (caprotinidae} nouveau de l'aptien du domaine mediterraneen central et oriental. geobios, 17/6, 723-732, lyon, 1984. 83. prvi nalaz rudistnog roda fossulites astre (hippuritacea) na području jugoslavije.glasnik zemalj. muzeja b.i h., prir. nauke, (n.s.), 24, 15-20, sarajevo, 1985. 84. kritički osvrt na "geologiju bih" knj. 2mezozojske . periode. glasnik zemalj. muzeja b. i h., prir. nauke, (n.s.);-24, 211-244, sarajevo, 1985. 85. polšak, ante & slišković, teofil: ugarella sladicae n. gen. n. sp., the new rudist from the maastri<!htian of the dinarides (yugoslavia). glasnik zemalj. muzeja b. i h., prir. nauke, (n.s.), · 25/26, 1-13, sarajevo,1986/87. 86. malez, mirko, lajtner, ivica, paunović, maja & slišković, teofil: kvartarnogeološka i 181 paleontološka proučavanja u spilji orlovači kod sarajeva (sr bosna i hercegovina).krš jugosl., 12/3, 39-75, zagreb, 1987. 87. friedrichkatzer (1861-1925).sjx>menica stogodišnjice rada zemaljskog muzeja b. i h. 1888 1988, 5660, sarajevo, 1988. 88. naučna djelatnost u oblasti geologije. spomenica stogodišnjice rada zemaljskog muzeja b. i h. 1888 1988, 179-193, sarajevo, 1988. 89. muzeološkadjelatnostgeološkog odjela.spomenica stogodišnjice rada zemaljskog muzeja b. i h. ·1888 1988, 294-306, sarajevo,1988. 90. a new praelapeirouseia (radiolitida} from the upper cretaceous sediments in the vicinity of višegrad in eastern bosnia glasnik zemalj. muzeja b. i h.,prir. nauke, (n.s.), 27,35-49, sarajevo, 1988. 91. genus milovanovicia (radiolitidae} in the dinaric range of yugoslavia development and stratigraphic position. -first intern. conf. on rudists, abstracts, str. 30, beograd, 1988. 92. malez, mirko, slišković, teofil & kapel, ante: gornjopleistocenski sisavci (mammalia) iz pe} ine kod ug1jevika (sr bosna i hercegovina, jugoslavija).glasnikzemalj. muzeja b .i h., prir. nauke, (n.s.), 27, 11-34, sarajevo, 1988. 93. malez, mirko, slišković, teofil, kapel, ante & op ašić, žarko: pećina hrustovača kod sanskog mosta i njezino paleontološko značenje. -naš krš, 14/24-25, 69-79, sarajevo, 1988. 94. jurišić-polšak, zlata & slišković, teofil: slatkovodni gastropodi neogenskih naslaga jugozapadne bosne. zbornik referata naučnog skupa" minerali, stijene, izumrli i živi svijet bosne i hercegovine", zemalj. muzej b. i h., prir.nauke, (n.s.), 167-174, sarajevo, 1989. 95. malez, mirko & slišković, teofil: kenozojski sisavci (mammalia} bosne i ht7cegovine.zbornik referata naučnog skupa "minerali, stijene, izumrli i živi svijet bosne i hercegovine", zemalj. muzej b. i h., prir. nauke, (n.s.), 99-214, sarajevo,1989. 96. malez, mirko & slišković, teofil: kronostratigrafske i morfometrijske značajke spiljskog medvjeda (ursus spelaeus rosenm. & heinroth} iz me gare na b jelašnici. -glasnik zemalj. muzeja b. i h., prir. nauke, (n.s.), 28,7-53, zagreb, 1989. . 97. pa vlovec, rajko, drobne, katica & slišković, teofil: problemi biostratigrafije paleogena u hercegovini. zbornik referata naučnog skupa "minerali, stijene, izumrli i živi svijet bosne i hercegovine", zemalj. muzej b. i h., prir. nauke, 131-134, sarajevo, 1989. 98. pa vwvić, milorad, malez, mirko & slišković, teofil: štajerska (angustidens) fauna u srbiji i bosni i hercegovini. zbornik referata naučnog skupa "minerali, stijene, izumrli i živi svijet bosne i hercegovine", zemalj. muzej b. i h., prir. nauke, / 182 215-220,sarajevo, 1989. 99. polsak, ante & slišković, teofll: vaccinites plenicari n. sp. a rudist from the senonian depos­ its of donje <:>re!je near zagreb and the surroundings of višegrad in eastern bosnia. -glasnik zemalj. muzeja b.i h., prir. nauke,(n.s.), 28, 55-64, sarajevo, 1989. 100. žagar-sakač, andrejka, slišković, teofil & sakač, krešimir: o vrsti unio katzeri brusina i srodnim oblicima u neogenskim slatkovodnim naslagama dalmacije i zapadne bosne. -zbornik geologia croatica 45 referata naučnog skupa "minerali, stijene, izumrli i živi svijet bosne i hercegovine", zemalj. muzej b. i h., prir. nauke, 157-166, sarajevo, 1989. 101. oistefanella gorancensis n. sp. from the upper cretaceous sediments of goranci near mostar (hercegovina). -glasnik zemalj. muzeja b. i h., prir. nauke, (n.s.), 29, 5-9, sarajevo, 1990. ova bibliografija vjerojatno nije potpuna iako su upotrebljeni svi raspoloživi podaci do kojih se moglo doći.bit ćemo zahvalni za sve ispravke i nadopune. 1. introduction in the frame of igcp575 (international geological correlation programme 575) a short well section of the ak-1x well (well name changed due to economic interests), located in the amasra area of the zonguldak basin of nw turkey (fig. 1 a, b), has been revised. an atypical co-occurrence of palynological species such as sinuspores sinuatus, vestispora fenestrata, v. laevigata, torispora securis, and few thymos­ pora spp. has been observed in the palynological assemblages from nw turkey. all these species are well-known and most form part of the ‘selected spore ranges and spore zonation of the carboniferous system in western europe’ (clayton et al., 1977), which became, in modified form, part of the ‘carboniferous time scale’ (e.g. gradstein et al., 2004). the application of this palynostratigraphic ab stra ct part of the ak-1x well section from the amasra area of the zonguldak basin in nw turkey (asia minor) has been palynologically revised. over the depth range –342.05 to –344.90 m atypical co-occurrences of the key stratigraphic spore species sinuspores sinuatus together with vestispora fenestrata, v. laevigata, torispora securis and thymo­ spora spp. are recorded. by correlation to the ‘selected spore ranges and spore zonation of the carboniferous system in western europe’, often used as a standard, these palynological assemblages would be correlated to the upper bolsovian by the presence of thymospora spp. with some reworked older material, represented by s. sinuatus. alternative spore ranges are considered in this study, and miospore ranges of selected species from western europe and north america are discussed. the correlation of the palynological record from the re-investigated ak-1x well section to the chronostratigraphy corresponds with ages around the duckmantian–bolsovian boundary, and correlation to the uppermost duckmantian is discussed as a possibility. however, recent studies lead to the conclusion that a lower bolsovian age determination for the ak-1x well section is also most probable. accordingly, sinuspores sinu­ atus has a slightly expanded range top in nw turkey and some taxa such as thymospora spp. occur slightly earlier here than in western europe. keywords: palynology, turkey, bashkirian, moscovian, duckmantian, bolsovian, westphalian b, westphalian c, atokan, sinuspores  geologia croaticageologia croatica co-occurrence of sinuspores sinuatus (artüz) ravn, 1986 with established palynological markers indicating younger strata: ak-1x well section (pennsylvanian, zonguldak basin, nw turkey) and the correlation to the stratigraphic system  ellen stolle1,2 1 institut für geographie und geologie, ernst-moritz-arndt-universität greifswald, friedrich-ludwig-jahnstr. 17a, 17489 greifswald, germany 2 *ep research, ennigerloh-westkirchen, germany; (ellen.stolle@yahoo.com) doi: 104154/gc.2012.27 geologia croatica 65/3 375–385 3 figs. 1 tab. 1 pl. zagreb 2012 geologia croatica 65/3geologia croatica 376 zonation to the palynological record of the ak-1x well section, would indicate the upper bolsovian (the upper westphalian c) for the investigated deposits from nw turkey. the enigmatic presence of sinuspores sinuatus would, in that case, have to be interpreted as being recycled from older rock material. in western europe and north america this spore is only known from deposits of the namurian, westphalian a, and westphalian b (stages according to the references of the original literature, e.g. in smith & butterworth, 1967, as punctatisporites sinuatus; in kosanke, 1988, as p. sinuatus; in peppers et al., 1993 as s. sinuatus). however, because the specimens of sinuspores sinuatus, identified in the ak-1x well section, as well as the surrounding palynofacies, showed no indication of reworking or recycling, attempts have been made in this study to look for alternative spore ranges and further evidence, of whether contemporaneous primary deposition of all these spores would have been possible. the first and last occurrences of miospore ranges presented in ravn (1986), howes (1988), and peppers & brady (2007) were particularly useful, in combination with the stratigraphic framework of gradstein et al. (2004) and ogg et al. (2008), in concluding an age around the duckmantian–bolsovian transition (westphalian b–westphalian c transition) for the palynological assemblages from nw turkey. 2. the study area: geological background the zonguldak basin is situated in the north–west of turkey (asia minor) on the black sea coast of the western pontides. the region belongs structurally to the istanbul-zonguldak terrane (also known as the istanbul zone, e.g. okay, 2008, fig. 1 a), which was, during carboniferous times, located within the tropics and more or less on the equator (e.g. stampfli, 2000). during the pennsylvanian epochs, deposition of mainly clastics and coals took place. at present, the zonguldak coalfield is a productive mining area (yalcin et al., 2002, see also for further aspects on general geology, stratigraphy and geological setting of the basin). the main mining districts are the armutcuk, zonguldak and amasra areas (fig. 1 b). the coal-bearing sequence is subdivided into the alacaagzi, kozlu and karadon formations, and is mainly composed of conglomerates, sandstones and figure 1: geographical and geological overview. map a) shows the wider frame of the study area and the structural affiliation. modified and simplified from okay & tüysüz (1999), okay & göncüoglu (2004), okay (2008), and stolle (2011). map b) focuses on the zonguldak basin and its coal mining districts. the approximate location of the ak-1x well is revealed. the map is simplified from yalcin et al. (2002). part of the pennsylvanian succession of the amasra area is simplified and depicted in c) for overview (alacaagzi, kozlu, and karadon formations). illustrated column according to the stratigraphy in tüysüz et al. (2004) (including the kozlu fm.), and modified from akbas et al. (2002) (where, as an example for outcrop stratigraphy, the karadon fm.– cakraz fm. contact is shown). a thickness of more than 500 m for the karadon fm. was recorded by canca et al. (1994) from well data (amasra-1 well). ellen stolle: co-occurrence of sinuspores sinuatus (artüz) ravn, 1986 with established palynological markers indicating younger strata... geologia croatica 377 claystones, though each unit has more or less characteristic lithologies in its area. the investigated interval of this study is assigned to the karadon formation of the amasra district. there, the karadon formation (named after the village karadon, e.g. ralli, 1933) lies conformably on the kozlu formation (canca et al., 1994; tüysüz et al., 2004) (fig. 1 c), and it is disconformably overlain by the permian-triassic cakraz formation (akbas et al., 2002), or by younger sediments (e.g. cretaceous in the subsurface, canca et al., 1994). according to well data, the formation can have a thickness of c. 500 m in the amasra area (canca et al., 1994; tüysüz et al., 2004). the zonguldak basin underwent strong tectonic deformation (folding and faulting, e.g. yalcin et al., 2002, fig. 1). tokay (1962) considered deposits from the amasra area to be an allochthonous group, consisting of displaced and mixed slides of westphalian c, b, a and namurian age deposits. the age determination of the karadon formation was controversial in the past, and the unit was defined as westphalian b, c and d (by dil & konyali, 1978), as westphalian a, b and c (by yergök et al., 1987)1, whereas kerey (1984) considered an age of westphalian b and c. karayigit & orhan (1997) assigned ages of westphalian b, c, and d. westphalian b and c were considered in a recent study by tüysüz et al., (2004). palynology and palaeobotany (macro plant fossils) were the main methods for the dating of clastic sections in the area. the pennsylvanian from nw turkey has traditionally been assigned to the european regional stages, for example to those that originated in the westphalian mining area of ‘ruhrgebiet’, germany. 3. material and methods this study is based on a revision of palynological data from the amasra area, nw turkey. dark claystones, rich in organic matter, and coals from a drill core of the ak-1x well served as the raw material for palynological processing according to standard preparation methods. the approximate location of the ak-1x well in the amasra area is shown in figure 1 b. the wider core section was assigned to the karadon formation (fig. 1 c). the lithology of the core segment, relevant for this study, is depicted in figure 2 as well as the productive sampling positions. the palynostratigraphic concept of this study was using events specific to a single taxon (e.g. its first and last occurrence), preferably of palynological markers and in comparison with different regions. previously, mclean et al. (2004), remarked (for a sequence along the langsettianduckmantian boundary in britain): “recognition of the biozonal boundaries of clayton et al. (1977) is also problematic, because the stratigraphic criteria that are used to define the base of the nj biozone (range top of s. rara, range top of sinuspores sinuatus, range base of microreticulatis­ porites nobilis) do not occur at the same horizon.”, and proposed: “the difficulties in these interpretations relate to using several criteria to define assemblages or assemblage biozones. a more suitable approach may be to define biostratigraphic units using events specific to a single taxon.” figure 2: the palynologically re-investigated ak-1x well section (this study) of the amasra area is shown with simplified lithologies. occurrences of the relevant species s. sinuatus are indicated (marked by the vertical thick line), together with palynologically productive sample positions. 1 yergök, f.a., akman, ü., tekin, f., karabalik, n.n., arbas, a., akat, u., armagan, f., erdogan, k. & karakullukcu, h. (1987): bati karadeniz bölgesinin jeolojisi i.– unpubl. report, mta report no. 2818, ankara. geologia croatica 65/3geologia croatica 378 during the palynological investigations of this study, the features of the entire palynological assemblage were also taken into consideration (e.g. composition/ main components, co-occuring taxa, content and condition of organic matter), and are involved in the interpretation of the palynological data. 4. co-occurrence of palynological species in the well section figure 2 shows the palynologically re-investigated ak-1x well section and the positions from where specimens of the distinct large brown, trilete spore species sinuspores sinu­ atus have been identified, (specimens illustrated in pl. 1, figs. 1–6). over the depth range –342.05 – –344.90 m s. sinuatus co-occurs with vestispora fenestrata, vestispora laevigata, torispora securis, and thymospora spp. (pl. 1). from the stratigraphic perspective this co-occurrence seemed to be unusual. all these species are well-known and most form part of the ‘selected spore ranges and spore zonation of the carboniferous system in western europe’ (clayton et al., 1977). the zonation has in the meantime been established, with slight modifications by partial updates, as the microfloral zonation component of the carboniferous time scale (gradstein et al., 2004). in clayton et al. (1977), the lower limit of the nj zone is marked by, amongst others, the youngest range of s. sinuatus (as punctatisporites sinuatus). the lower limit of the nj zone related to the early westphalian b in 1977, is now equivalent with the lower duckmantian and upper bashkirian. according to clayton et al. (1977), the base of the succeeding sl zone (considered to be lowermost westphalian c by the authors), coincides with the appearance of the first monolete spores torispora securis and vestispora fenestrata. the lower limit of the succeeding ot zone (equating to the boundary between westphalian c and d according to the authors), coincides with the appearance of monolete verrucose spores of the genus thymospora. applying the ‘zonation of the carboniferous system in western europe’ to the palynological record from the ak-well section from nw turkey, would result in an age determination in the range from latest bolsovian (westphalian c) to asturian (westphalian d), or younger, based on the presence of thymospora spp. occurrences of sinuspores sinuatus would have to be interpreted as being reworked from older strata. s. sinuatus was first described by artüz from the sulu and büyük seams of the zonguldak area of nw turkey, later recorded by ibrahim-okay & artüz (1964) from the domuzcu seam. the early finds were considered to be from westphalian a sediments, as well as records for example in akyol (1974) (westphalian a, namurian) and nakoman (1976, e.g. as sinuspores sinuatus and cani­ sporites corpulentus) from the same area. akgün & akyol (1992) reported it from the amasra area (as sinuspores cor­ onatus) as well as agrali & konyali (1967, as sinu­ spores sinuatus and s. coronatus). outside of nw turkey, the spore was recorded from europe and north america, for example from the russian platform (einor, 1996), scotland (butterworth & williams, 1958) and the north american midcontinent (ravn & fitzgerald, 1982) under s. sinuatus or under a synonym. according to the common literature the age range was considered to be (late) visean (e.g. ettensohn & peppers, 1979; einor, 1996) to late westphalian b (kosanke, 1988, west virginia). whether a) sinuspores sinuatus identified in the short ak-1x section is the same as the type species of artüz (1957), and whether b) the assignment of the ak-1x section to the duckmantian (westphalian b), based on the record of kosanke (1988), would be explicable and reliable is the subject of the following discussion. 5. brief taxonomic outline – s. sinuatus from the type area sinuspores sinuatus (artüz) ravn 1986 was first described by artüz (1957) from the type locality in the zonguldak district of the zonguldak basin, as having a size of 90–130 µm, a trilete mark of ¾ of the radius, slightly opened and straight. on the surface of the spore are sine curve-like infrastructures present, which appear on the dark background as a light construction. at the margin of the spore body, a deep dark brown equatorial zone exists, which is 15–17 µm broad and structureless. in his emendation of the species, ravn (1986) attributed a wider size range of 75–130 µm, and an exine thickness of 5 µm and more. smith & butterworth (1967) described their specimens (under punctatisporites sinuatus) as having an exine up to 5 µm in thickness (laevigate and with fine infrasculpture), usually highly folded, with folds broad and situated around the periphery of the spore, but sometimes also following the laesurae, giving the appearance of broad lips. the thickness of the exine (thickenings at sine curve-like structures and/or exine accumulation by fold) is responsible for the dark brown areas on the spore body. the specimens found in the short ak-1x well section (e.g. pl. 1, figs. 4–6) are clearly assignable to the species s. sinuatus, based on their morphological features, such as distinct sine curve-like structures, the deep dark brown belt zone at the margin of the spore body, and sizes given in the original description. 6. correlation of miospore ranges and dating the palynological record of the ak-1x well section (see appendix i for more details) has been compared to palynological events beyond western europe. ravn (1986) showed miospore ranges from iowa, and also presented a comparison chart of the iowa records compared with other regions (north america, western europe; fig. 3 a). the given picture of first and last occurrences appears to be more individual in contrast to an overall zonation. however, it should be noted that dating was an individual process based on personal interpretation by each author. ravn (1986) correlated the first occurrences of vestispora fenestrata, tori­ spora securis, and particularly those of vestispora laevigata and thymospora spp. from the upper kilbourn and lower ellen stolle: co-occurrence of sinuspores sinuatus (artüz) ravn, 1986 with established palynological markers indicating younger strata... geologia croatica 379 plate 1 miospores of the ak-1x well from the pennsylvanian of nw turkey, relevant for this study. each with dimensions in micrometres, slide number, and england finder coordinates. 1 sinuspores sinuatus, 101 µm, ak-1x/7.1.2, q28.4. 2 sinuspores sinuatus, 91 µm, ak-1x/17.1, o47, a relatively unfolded specimen. 3 sinuspores sinuatus, 106 µm, ak-1x/7.1, u28.4. 4 sinuspores sinuatus, same specimen as in 1), with focus on the trilete mark. 5 sinuspores sinuatus, same specimen as in 1), with focus on an area with more or less well developed sine curve-like structures. 6 sinuspores sinuatus, same specimen as in 1), with focus on an area, which appears relatively laevigate. 7 vestispora costata, 106 µm, ak-1x/7.1.2, s48.3. 8 vestispora fenestrata, 107 µm, ak-1x/7.1.1, l48.4. 9 vestispora laevigata, 80 µm, ak-1x/7.3, d42. 10 torispora securis, 24 µm, ak-1x/7.1.2, p29.3. 11 thymospora sp., 31 µm, ak-1x/7.3, c31. 12 torispora securis, 29 µm (one specimen), ak-1x/7.1.2, s48.3. 13 raistrickia fulva, 58 µm (including ornament), ak-1x/19.1, c32.4. geologia croatica 65/3geologia croatica 380 kalo formations to the upper westphalian b (fig. 3 b, also in howes, 1988). ravn’s (1986) dating approximately corresponds with a foraminiferal dating by lambert (1988a) from the iowa coal succession, namely from shale below the thick limestone overlying the laddsdale coal (fig. 3 b). lambert (1988a) related the investigated strata to the beedeina zone (most of the specimens were ‘primitive’ forms of the genus beedeina). notably, some remaining species represented one of the youngest occurrences of the genus fusulinella (‘youngest’ in an evolutionary sense). according to gradstein et al. (2004) the first fusulinella are correlated approximately with the mid bolsovian (mid westphalian c, late atokan) (fig. 3 c). according to ogg et al. (2008), the first fusulinella are correlated with the late bolsovian (mid westphalian c, late atokan) (fig. 3 d). the presence of the conodont species neognathodus medadulti­ mus in overlying strata from the lower part of the floris formation (lambert, 1988b; howes & lambert, 1988, e.g. p. 32) support these correlations. the appearance of n. medadultimus is according to gradstein et al. (2004, table 15.2, selected isotopic radiometric age dates) correlated with the upper kashirian of the moscow basin (mid moscovian, approximate bolsovian–asturian transition according to ogg et al., 2008). discussion of the biostratigraphic data from the underlying kalo formation (fig. 3 b) requires a more comprehensive explanation. however, lambert (1988b) stated that the conodont genera idiognathoides and declinognathodus do not range above the blackoak coal, and the species ne­ ognathodus bothrops was explicitly identified from a limestone lens which overlies the blackoak coal (howes & lambert, 1988) (fig. 3 b). it should be noted that the ne­ ognathodus medexultimus–neognathodus bothrops zone, (standard conodont zones of gts2004 diagrams from russian chart, gradstein et al., 2004), is correlated to the early moscovian (around 311 ma, fig. 3 c), and includes according to ogg et al. (2008) the early bolsovian (early westphalian c, mid atokan). barrick et al. (2004) stated that neognathodus uralicus is a distinctive morphotype that is common in the southern midcontinent, but has been referred incorrectly for instance to neognathodus medexul­ timus. n. uralicus occurs in the neognathodus atokaensis zone, (conodont zones midcontinent north america), which was correlated by barrick et al. (2004, fig.1) to the mid atokan (compare figs. 3 c, d). the underlying kilbourn formation of the lower cherokee group (fig. 3 b) represents initial middle pennsylvanian deposition (e.g. anderson, 2007, fig. 5, pennsylvanian and mississipian stratigraphic column of iowa, iowa geological survey). accordingly, the base of the formation is assigned to the lowest middle pennsylvanian, but may range to the uppermost lower pennsylvanian. the lowest base of the formation corresponds, according to ogg et al. (2008), with the uppermost bashkirian (fig. 3 b), or with the early atokan and a mid/ late duckmantian, latest early pennsylvanian, respectively (fig. 3 d). a recent paper of peppers & brady (2007) correlates the first occurrences of vestispora fenestrata and tor­ ispora securis to approximately the mid atokan (lowermost westphalian c) (fig. 3 e). their records from the illinois basin range stratigraphically down to the uppermost westphalian b (uppermost duckmantian). their records from kansas range down to the lowermost westphalian c (lowermost bolsovian). peppers & brady’s (2007) correlation of the regional stages (approximately mid atokan – westphalian b–westphalian c boundary) is in accordance with gradstein et al. (2004) (fig. 3 c). it corresponds with gradstein’s et al. (2004) duckmantian–bolsovian transition (westphalian c–westphalian b and bashkirian– moscovian transition, respectively). following kosanke (1988) with his range top of s. sinuatus in the uppermost westphalian b (uppermost duckmantian), and considering the miospore ranges of ravn (1986), howes (1988), and peppers & brady (2007), a ‘co-deposition’ or co-occurrence of s. sinuatus with the other palynological markers mentioned above, is clearly possible, based on contemporaneous occurrences of the parent plants. adapting peppers & brady’s (2007) correlation of the regional stages (fig. 3 e) to the carboniferous regional subdivisions of ogg et al. (2008), (fig. 3 d), peppers & brady’s approximate mid atokan (first occurrence t. securis, first occurrence v. fenestrata) correlates to the earliest bolsovian (early moscovian). in comparison with the data shown above, the investigated ak-1x well section of this study clearly correlates apfigure 3: charts of miospore ranges and carboniferous subdivisions. in a): comparison chart of selected miospore ranges observed in iowa (ravn, 1986 = r) to those reported from other areas (clayton et al., 1977, western europe = c; smith & butterworth, 1967, britain = s; loboziak, 1974, western europe = l; van wijhe & bless, 1974, western europe = v; peppers, 1970, 1979, illinois basin = p). modified from ravn (1986). only species which also have been identified in ak-1x well section (this study) were chosen for illustration. the horizontal band, marks in comparison, the oldest age suggestion for the ak-1x well section (by the occurrence of v. laevigata). in b): extract from howes (1988), and expanded. howes referred to miospore ranges of ravn (1986) and his depiction of stratigraphic units in iowa as well as on coal occurrences of the region. foraminifer and conodont records of lambert (1988a, b) are for this study included in chart b) as well as dating of the kilbourn fm., compiled and illustrated by anderson (2007). the oldest age suggestion for the ak-1x well section (in comparison, by the occurrence of v. laevigata) is marked again as a horizontal band. in c): some pennsylvanian stages in relation to the regional subdivisions of the carboniferous time scale of gradstein et al. (2004). the extension of the north america regional stage ‘atokan’ for comparison with charts d) and e) is marked. the relevant foraminiferal event (from gradstein et al., 2004) has been included to chart c) for overview and comparison with charts a) and b) as it represents ‘age control’ for the palynological events. chart d) displays the latest published relationships of some pennsylvanian stages to the regional subdivisions of the carboniferous time scale (ogg et al., 2008). the positions of relevant foraminifer and conodont results are included for overview (‘age control’ for the iowa stratigraphic units in chart b) (conodont zones according to gts2004, gradstein et al., 2004; barrick et al., 2004; ogg et al., 2008). in e): extract of chart of selected miospore ranges observed in the kansas and illinois basins in relation to the regional stages (from peppers & brady, 2007). the european regional stages probably have been adapted to the ‘atokan’ according to correlations of gradstein et al. (2004) (compare to c). ellen stolle: co-occurrence of sinuspores sinuatus (artüz) ravn, 1986 with established palynological markers indicating younger strata... geologia croatica 381 geologia croatica 65/3geologia croatica 382 proximately to the duckmantian–bolsovian transition (westphalian b–westphalian c transition). this is corroborated by a comprehensive palynological data record from the amasra area of the zonguldak basin. the range charts from agrali & konyali (1969) include a) the vertical extensions of 108 form genera (tab. 1), and b) the vertical extension of the species from 52 genera (tab. 2, i. sporites, and tab. 3, ii. pollenites); their source material were cores from 18 wells and samples from mining galleries. some taxa were reliably identified from their plates and descriptions. the palynological events of selected taxa, relevant for this study, were extracted from their charts and are compiled in table. 1 from older to younger. the short interval of the ak-1x well can be placed between positions (3) and (4). species from (1) and (3) are already part of the palynological assemblages. sinuspores sin­ uatus still occurs at this position, up to (4). spinosporites species under (2) could not clearly be identified from the ak-1x well section. agrali & konyali (1969) observed that the presence of certain miospore types has very limited horizontal extension (regarding their entire study area). considering the possibility of reworking or recycling of older rock material during the process of deposition, it should be noted that no other species besides s. sinuatus occur in the ak-1x well section that would indicate older ages (e.g. langsettian or early duckmantian, such as schul­ zospora spp., bellispores spp., in peppers, 1996; owens et al., 2004). the environment of sedimentation in the positions of the coal band (fig. 2), where s. sinuatus is present, can be described as relatively autochthonous. an extremely well-preserved microflora within those palynological assemblages displays the facies of a typical coal swamp. sample ak-1x/18 includes as the main components torispora 50%, laevigatosporites 22%, densosporites 14 %, florinites 12 %, and punctatosporites; ak-1x/19 includes laevigat­ osporites 93%, florinites 3 %, and cirratriradites. bisaccate pollen (signals from the hinterland) are non existent. the composition of the miospores (mainly from ferns and lycophytes) displays the influence of peat substrate and clastic substrate ever-wet vegetations of dimitrova et al. (2011), and the subordinate influence of a marginal vegetation. dimitrova et al. (2011) proved that the florinitesproducing cordaitanthaceans appear not to have been upland trees (as previously suggested), but occupied mainly coastal habitats, or riparian habitats on the margins of the wetland. in other respect, no further species,which would indicate younger ages (e.g. a latest bolsovian, asturian), time-equivalent with occurrences of thymospora spp. as for example shown in the range chart from western europe in clayton et al. 1977 (e.g. spinosporites spinosus, angulisporites splen­ didus or savitrisporites camptotus), occur in the ak-1x well section. these latter species are common in younger strata from nw turkey (stolle & buzkan, 2011; stolle unpublished data). even a key stratigraphic marker from clayton’s et al. (1977) zonation supports the considerations of this study. raistrickia fulva (pl. 1, fig. 13; the holotype was described from the zonguldak area) is present in the palynological assemblages, also in those of coal sample ak-1x/19 (see above, and fig. 2). the upper range of r. fulva is according to clayton et al. (1977) at the top of the nj zone, and indicates as its youngest age, the earliest bolsovian (westphalian c). according to owens (in stephenson & owens, 2006), the species only ranges from kinderscoutian to duckmantian. whether the ages and relationship to the stages could be refined for the ak-1x well section is discussed below. 7. discussion as shown above, the co-occurrence of sinuspores sinuatus and vestispora fenestrata, v. laevigata, torispora securis, and few thymospora spp. is most likely based on contemporaneous first occurrences. therefore dating of the ak-1x well section over the depth range –342.05 – –344.90 m, where these marker species occur, is in this study for the first time broadly related to the duckmantian–bolsovian transition (westphalian b–westphalian c transition). following ravn (1986) and howes (1988), and also owens (in stephenson & owens, 2006) regarding the upper range of raistrickia fulva, the ak-1x well section could correspond to the uppermost duckmantian (uppermost westphalian b). the record of s. sinuatus in the amasra area of nw turkey and that of kosanke (1988, west virginia, upper westphalian b) would be approximate time-equivalents. owens (1996) depicted a table of ‘principal upper carboniferous palynological events in the northern hemisphere’, in which the appearance of torispora is placed at the base of the bolsovian (westphalian c). following owens (1996), and also peppers and brady (2007, their kansas record with first vestispora fenestrata and tor­ ispora securis in their lowermost westphalian c), and furthermore ogg et al. (2008) with the relationship that ‘peppers and brady’s mid atokan would be earliest bolsovian (westphalian c)’, consequently the ak-1x well section would correspond to the lower bolsovian (lower westphalian c; lower moscovian). the miospore range top regarding s. sinuatus would, according to this latter stratigraphic model, be slightly expanded in the amasra area. similar results have already been shown by agrali & konyali (1969) (tab. 1), however, their reference to the regional stages (range top upper westphalian c) has to be revised (details in prep., stolle et al.). table 1: sequence of palynological events from selected palynological taxa from the amasra area, nw turkey. younger (4) range top of sinuspores sinuatus (3) range base of vestispora fenestrata (as foveolatisporites fenestratus) (2) range base of spinosporites (genus) (1) range base of torispora spp. (incl. t. securis) / thymospora spp. / vestispora (genus) older based on data from agrali & konyali (1969) ellen stolle: co-occurrence of sinuspores sinuatus (artüz) ravn, 1986 with established palynological markers indicating younger strata... geologia croatica 383 8. conclusions an atypical co-occurrence of miospore species such as si­ nuspores sinuatus, vestispora fenestrata, v. laevigata, tori­ spora securis and thymospora spp. is observed in palynological assemblages from a short well section from the amasra area of the zonguldak basin of nw turkey. palynological re-investigation herein provides an age which corresponds with a time interval around the duckmantian–bolsovian transition (westphalian c–westphalian b boundary and approximating to the bashkirian–moscovian transition, respectively). a correlation to the uppermost duckmantian (uppermost westphalian b; bashkirian–moscovian transition) for this section is possible. however, recent studies lead to the conclusion that a correlation to the lower bolsovian (lower westphalian c; lower moscovian) for the ak-1x well section is most likely. this means that sinuspores sinuatus has a slightly expanded range top in nw turkey and some taxa such as thymospora spp. occur slightly earlier here than in western europe. acknowledgement the author is grateful to m. namik yalcin (department of geological engineering, istanbul university, turkey) for providing the research material, for comments and suggestions. nigel hooker (saudi aramco) and an anonymous reviewer are thanked for comments and suggestions on the manuscript. this paper is a contribution to igcp project no. 575. appendix i additional taxa of the palynological record of the ak-1x well section, co-occurring with sinuspores sinuatus alatisporites pustulatus, alatisporites spp., calamospora spp., cingulizonates sp., cirratriradites saturnii, crassis­ pora kosankei, densosporites triangularis, densosporites sp., dictyotriletes bireticulatus, endosporites globiformis, florinites junior, florinites mediapudens, laevigatosporites spp., lycospora sp., murospora kosankei, punctatisporites spp., punctatosporites spp., raistrickia fulva, raistrickia spp., reinschospora spp., reticulatisporites reticulatus, thymospora spp., torispora securis, triquitrites spp., ves­ tispora costata, vestispora fenestrata, vestispora laevigata appendix ii full names (brief history) of species mentioned in this paper alatisporites pustulatus (ibrahim) ibrahim, 1933 angulisporites splendidus bhardwaj, 1954 canisporites corpulentus nakoman, 1967 (synonymous to si­ nuspores sinuatus (artüz) ravn, 1986) cirratriradites saturnii (ibrahim), schopf, wilson & bentall, 1944 crassispora kosankei (potonié & kremp) bhardwaj, 1957 emend. smith & butterworth, 1967 densosporites triangularis kosanke, 1950 dictyotrilets bireticulatus (ibrahim) potonié & kremp, 1954 emend. smith & butterworth, 1967 endosporites globiformis (ibrahim) schopf, wilson & bentall, 1944 florinites junior potonié & kremp, 1956 florinites mediapudens (loose) potonié & kremp, 1956 foveolatisporites fenestratus (kosanke & brokaw) bhardwaj, 1956 microreticulatisporites nobilis (wicher) knox, 1950 murospora kosankei somers 1952 (synonymous to westpha­ lensisporites irregularis alpern, 1958) punctatisporites sinuatus (artüz) neves, 1961 (synonymous to sinuspores sinuatus (artüz) ravn, 1986) raistrickia fulva artüz, 1957 (first description from the zonguldak area, nw turkey) reticulatisporites reticulatus (ibrahim) ibrahim, 1933 savitrisporites camptotus (alpern) doubinger, 1968 (synonymous to savitrisporites majus bhardwaj, 1957) schulzospora rara kosanke, 1950 sinuspores coronatus and sinuspores (punctatisporites) coronatus from agrali & konyali (1969) (new comb i nation, no explanation given) adopted from punc ta ti spo­ rites coronatus butterworth & williams, 1958, synonymous to punctatisporites sinuatus (artüz) neves 1961 by smith & butterworth (1967), synonymous to si­ nuspores sinuatus (artüz) ravn, 1986 sinuspores sinuatus (artüz) ravn, 1986 spinosporites exiguus upshaw & hedlund, 1967 spinosporites spinosus alpern, 1958 torispora securis (balme) alpern, doubinger & horst, 1965 triquitrites sculptilis (balme) smith & butterworth, 1967 vestispora costata (balme) bhardwaj emend. spode, in smith & butterworth, 1967 vestispora fenestrata (kosanke & brokaw) wilson & venkatachala emend. spode, in smith & butterworth, 1967 vestispora laevigata wilson & venkatachala, 1963 neognathodus atokaensis grayson, 1984 neognathodus bothrops merrill, 1972 neognathodus medadultimus merrill, 1972 neognathodus medexultimus merrill, 1972 neognathodus uralicus nemirovskaya & alekseev, 1994 geologia croatica 65/3geologia croatica 384 references agrali, b. & konyali, y. (1969): etüde des microspores du bassin carbonifere d’amasra.– bulletin of the mineral research and exploration institute of turkey, 73, 45–132. akbas, b., altun, i.e. & aksay, a. (2002): 1 : 100 000 ölcekli türkiye jeoloji haritalari no: 24 zonguldak – e 28 paftasi [geological map of turkey 1:100000, zonguldak sheet e 28– in turkish]. mta genel müdürlügu, ankara, jeoloji etütleri dairesi, ankara, 18 p. akgün, f. & akyol, e. (1992): amasra-bartın karbonifer havzası kömürlerinin palinolojisi ve paleoekolojisi.– turk.. j. earth sci., 1, 49–56. akyol, e. (1974): zonguldak üzülmez bölgesi, asma bölümündeki –50 kotlu galeri güney ve doğu kanatlarının kestiği namuriyen ve vestfaliyen a yaşlı damarların palinolojik incelemeleri.– mta enst. derg., 83, 47–108. anderson, r.r. (2007): geology of the red rock dam and visitir center, marion county, iowa.– geol. soc. of iowa, guidebook 80, iowa city, 14 p. artüz, s. (1957): die sporae dispersae der türkischen steinkohle von zonguldak – gebiet (mit besonderer beachtung der neuen arten und genera).– rev. fac. sci. l’univ. istanbul. ser. b, 22, 239–278. barrick, j.e., lambert, l.l, heckel, p.h. & boardman, d.r. (2004): pennsylvanian conodont zonation for midcontinent north america.– revista espanola de micropaleontologia, 36, 231–250. butterworth, m.a. & williams, r.w. (1958): the small spore floras of coals in the limestone coal group and upper limestone group of the lower carboniferous of scotland.– t. roy. soc. edin. earth, 63, 353–392. canca, n., barlas, o., keyf, s., erdogan, c., tunckilic, g. & yalcin, r. (1994): jeoloji etüdleri dairesi ve enerji hammade etüd arama dairesi haritalarindan derlenerek bati karadeniz bölge müdürlügü tarafindan düzenlenmistir. zonguldak 1993.– maden tetkik ve arama genel müdürlügü, litostratigrafi birimleri serisi-1, ankara, geological map 1:25 000. clayton, g., coquel, r., doubinger, j. gueinn, k.j., loboziak, s., owens, b. & streel, m. (1977): carboniferous miospores of western europe: illustration and zonation, report of commission internationale de microflore du paléozoïque working group on carboniferous stratigraphical palynology.– mededelingen rijks geolog. dienst, 29, 1–71. dil, n. & konyali, y. (1978): carboniferous of zonguldak area. in: field excursion on the carboniferous stratigraphy in turkey, guidebook. mta public., ankara, 5–25. dimitrova, t.k., cleal, c.j. & thomas, b.a. (2011): palynological evidence for pennsylvanian extra-basinal vegetation in atlantic canada.– j. geol. soc. london, 168, 559– 569. doi: 10.1144/ 0016-76492010-028 einor, o.l. (1996): the former u.s.s.r. – in: wagner, r.h., winkler prins, c.f. & granados, l.f. (eds.): the carboniferous of the world iii, the former u.s.s.r., mongolia, middle eastern platform, afghanistan and iran. iugs publication 33. instituto tecnológico geominero de españa –nationaal natuurhistorisch museum, madrid, 3–408. ettensohn f.r. & peppers, r.a. (1979): palynology and biostratigraphy of pennington shales and coals (chesterian) at selected sites in northeastern kentucky.– j. paleontol., 53 /2, 453–474. gradstein, f.m., ogg, j.g. & smith, a.g. (eds.) (2004): a geologic time scale 2004.– cambridge university press, cambridge, new york, melbourne, 589 p. howes, m.r. (1988): palynology of cherokee group coals.– in: howes, m.r. & lambert, l.l. (eds.): stratigraphy and depositional history of the cherokee group, south-central iowa. geol. soc. of iowa, guidebook 49, 15–21. howes, m.r. & lambert, l.l. (1988): stratigraphy and depositional history of the cherokee group, south-central iowa.– geol. soc. of iowa, guidebook 49, iowa city, 39 p. ibrahim-okay, a.c. & artüz, s. (1964): die mikrosporen der steinkohlenflöze domuzcu und cay (westfal a) im zonguldak gebiet (türkei). – fortschr. geol. rheinld. u. westf., 12, 271–284. karayigit, a.i. & orhan, e. (1997): zonguldak coal basin. excursion guide.– european coal conference ‘97, dokuz eylül üniversitesi, izmir, 5–10 may 1997, 18 p. kerey, i.e. (1984): facies and tectonic setting of the upper carboniferous rocks of nw turkey. – in: dixon, j.e. & robertson, a.h.f. (eds.): the geological evolution of the eastern mediterranean. geol. soc. london, spec. public., 17, 123–128. kosanke, r.m. (1988): palynological studies of middle pennsylvanian coal beds of the proposed pennsylvanian system stratotype in west virginia.– u.s. geological survey, professional paper, 1455, 73 p. lambert, l.l. (1988a): fusulinids from the cherokee group of iowa.– in: howes, m.r. & lambert, l.l. (eds.): stratigraphy and depositional history of the cherokee group, south-central iowa. geol. soc. of iowa, guidebook 49, 23–26. lambert, l.l. (1988b): cherokee group conodonts from southeastern iowa.– in: howes, m.r. & lambert, l.l. (eds.): stratigraphy and depositional history of the cherokee group, south-central iowa. geol. soc. of iowa, guidebook 49, 27–30. loboziak, s. (1974): considerations palynologiques sur le westphalian d’europe occidentale.– rev. palaeobot. palyno., 18, 271–289. mclean, d., owens, b. & bodman, d. (2004): palynostratigraphy of the late carboniferous langsettian-duckmantian boundary in britain.– in: beaudoin, a.b. & head, m.j. (eds.): the palynology and micropalaeontology of boundaries.– special publication of the geological society of great britain, 230, 123–135. nakoman, e. (1976): zonguldak kömür havzasının karadon ve üzülmez bölgelerindeki namuriyen ve vestfaliyen a taşlı damarların palinolojl incelemeleri. ii. nicel etüd.– m.t.a. enst. derg., 87, 80–110. ogg, j.g., ogg, g. & gradstein, f.m. (2008): the concise geologic time scale.– cambridge university press, cambridge, new york, melbourne, 177 p. okay, a.i. (2008): geology of turkey: a synopsis.– anschnitt, 21, 19–42. okay, a.i. & göncüoglu, m.c. (2004): the karakaya complex: a review of data and concepts.– turk. j. earth sci., 13, 77–95. okay, a.i. & tüysüz, o. (1999): tethyan sutures of northern turkey.– geol. soc. london, spec. publ., 156, 475–515. owens, b. (1996): upper carboniferous spores and pollen.– in: jansonius, j. & mcgregor, d.c. (eds.): palynology: principles and applications, 2. american association of stratigraphic palynologists foundation, dallas, 597–606. owens, b., mclean, d. & bodman, d. (2004): a revised palynozonation of the british namurian deposits and comparisons with eastern europe.– micropaleontology, 50, 89–103. doi: 10.2113/ 50.1.89 peppers, r.a. (1970): correlation and palynology of coals in the carbondale and spoon formations (pennsylvanian) of the northeastern part of the illinois basin.– illinois geol. survey bull. 93, 173 p. peppers, r.a. (1996): palynological correlation of major pennsylvanian (middle and upper carboniferous) chronostratigraphic boundaries in the illinois and other coal basins.– geol. soc. am. mem., 188, 1–111. ellen stolle: co-occurrence of sinuspores sinuatus (artüz) ravn, 1986 with established palynological markers indicating younger strata... geologia croatica 385 peppers, r.a. & brady, l.l. (2007): palynological correlation of atokan and lower desmoinesian (pennsylvanian) strata between the illinois basin and the forest city basin in eastern kansas.– cur. res. earth sci., bull. 253, part 1, 1–21. peppers, r.a., howe, w.b. & deason, k. (1993): palynological zonation and physical stratigraphy of pre-desmoinesian strata along a subsurface cross section in northwestern missouri.– geol. soc. of america, annual meeting of north–central section, abstracts with program, 25, p. 72. ralli, g. (1933): le bassin houiller d’héraclée et la flore du culm et du houiller moyen.– zellitch, istanbul, 100 p. ravn, r.l. (1986): palynostratigraphy of the lower and middle pannsylvanian coals of iowa.– iowa geol. survey, technical paper no.7, iowa city, 245 p. ravn, r.l. & fitzgerald, d.j. (1982): a morrowan (upper carboniferous) miospore flora from eastern iowa, u.s.a.– palaeontogr. abt. b, 183/4–6, 108–172. smith, a.h.v. & butterworth, m.a. (1967): miospores in the coal seams of the carboniferous of great britain.– special papers in palaeontology, no. 1, london, 324. p. stampfli g.m. (2000): tethyan oceans.– in: bozkurt, e., winchester, j.a. & piper, j.d.a. (eds.): tectonics and magmatism in turkey and the surrounding area. geol. soc. london, spec. public., 173, 1–23. stephenson, m.h. & owens, b. (2006): taxonomy online 2: the ‘bernard owens collection’ of single grain mount palynological slides: carboniferous spores part i.– british geological survey research report, rr/06/05, keyworth, 80 p. stolle, e. (2011): pollen-dominated “european” palynological assemblages from the permian of nw turkey (asia minor) – palaeogeographical context and microfloral affinities.– geol. q., 55/2, 181–186. stolle, e. & buzkan, i. (2011): first documented palynological record from kasimovian deposits of the zonguldak coal basin, nw turkey.– in: hakansson, e. & trotter, j.a. (eds.): programme & abstracts: the xvii international congress on the carboniferous and permian. geological survey of western australia, perth, australia, p. 118. tokay, m. (1962): the geology of the amasra region with special reference to some carboniferous gravitational gliding phenomena.– m.t.a. bull., 55, 1–20. tüysüz, o., aksay, a. & yigitbas, e. (2004): bati karadeniz bölgesi litostratigrafi birimleri.– maden tetkik ve arama genel müdürlügü, litostratigrafi birimleri serisi-1, ankara, 92 p. van wijhe, d.h. & bless, m.j.m. (1974): the westphalian of the netherlands with special reference to miospore assemblages.– geol. mijnb., 53, 295–328. yalcin, m.n., inan, s., gürdal, g., mann, u. & schaefer, r.g. (2002): carboniferous coals of the zonguldak basin (northwest turkey): implications for coalbed methane potential.– aapg bull., 86/7, 1305–1328. doi: 10.1306/61eedc88-173e-11d78645000102c1865d manuscript received march 23, 2012 revised manuscript accepted october 08, 2012 available online october 30, 2012 geol. c roat. 49/2 1135 1431 8 figs. 1 3 tabs. 1 1 zagreb 1996 geochemical study of oils and oil source rock from the eastern drava and siavonija-srijem depressions, pannonian basin, croatia anda alajlleg',.t. michael moldowan2 , gerard.t. demaison', vladimir jelaska", zeljka llrodlc-jakupak', dubravko svilkovic' and bradly j. huizinga6 key words: biomarkers, geochemical parameters, oil , oil source rock, organic geochemistry. abstract a middle miocene oi1 source rock has been identified by geo­ chemical logging of exp loration wells in the eastern drav(l depres­ sion (edd) and in the siavonija-srijclll dep ression (ss d) al the soulh-cas t margin o f ihe p<uhlonian basin, cro:li ia. the source rock contains type ii to ii / iii kerogen. ,mel reaches carly maturity stage at <icplhs of about 2400 m. the mesozoic seq uences wefe found either to be absent or \0 be poor in organic mallcr within ihe analysed wells . acco rd ing to c27-cz~-c'9 stcranc and c27-c2~-c2' !11onoaromati c steroid distributions , gtl !11m:lcerane indices, c.15 homohopanc indiccs and prcsence of c x! stefancs, the edd and ssd o il s wcre generated from the same marine sotlrce rock . the distribut ion o f homo hopanes and high ni/(ni + v) porphyri n r~hios indicates ihat the related source rock was deposited under s uboxic conditions. the oi ls appear to have been generated from ihe sou rce rock during the early to midd le stages of maturity. t he oi ls are waxy, wilh pom points up to 30°c and sul­ phur contents not exceedi ng 0.7%. j. introduction the eastern drava (e dd) and siavon ija-srijem (ssd) depressions share the common geologica l history or lhe soll lh pannonian bas in (ro yd en & hor­ vattl , 1988). this area has been studied by l-lernitz ( 1983) and pandzic (1 986). the basement, which is most ly composed o r a l11elamorphic complex intruded by he rcynian grani tes (pamic, 1986), is overlain by ihe palaeozoic phyllites, quarlzites, lurfs, exlrusivcs and clastics. kljucne rijeci: biomurkeri, geokemijski pa rametr i, nana, naftnomaticna stijena, organska geokem ija. sazctak telllcljem geokcmijskih podat~\ka za istrazile busotinc identitic i­ rana je srcd njomioccnska naftnomalicna slijcna u ]slocnodravskoj i siavons ko -srijcmskoj polol il1i, nl! jugoislocnom ru bu panonskog baz:ena , h.-vats ka . maticna stijena sad rz i kerogen li pa ii. do 11 ./1 11. s t<ldij ra lle zrclos ti mal icna s tijcna dosci.c otprilikc na c1t1 bini zalijc­ ganja od 2.400 m. u ispitivanim busotinama zit mezozoj skc jc slojeve utvrdeno cia sli siromasn i organskolll tvari iii da slojcvi nc(!osl<iju. prcj11a raspodjcli cnc2~-c29 sterana i c27 c2s-c2~ mo noaro­ m<1l sk ih stero ida , ie gamaccfallskih indeksa, c35 holll o!lopans kih indeksa i prislitnosli c30 stefana, edd i ssd naftc 51! olplls\c nc od isle marins ke maticnc stijcne. raspodjela homohopan:l i visok i por­ !"i .ins ki omjeri ni/(n i +v) ukazuju da je odnosna maticna s lijcll<l ista lol.ena u suboksicnim llvjclima. nafte sll otpustcnc od nmticne sli ­ jcnc 1i siad iju njezine rane do srcdnje zrclosti. t o sli visokoparafinskc naftc sa sti ni slcm do 30°c, a sadr7.aj sll mpora nc prclaz i 0.7 %. prom penno-'fr iassic to latc t riassic a subs iding ca rbonate platform was widespread, gene rat ing lime­ stones and dolomites. pe lagic sediment ati on in the jurassic mainly produced muddy limestones. cretaceous lithofacies include both shelf and deep sea clast ics . in th e tethyan region, rclal cd to ocean anoxic events, "scag lia" fac ies were genera ted in the upper cretaceous. compressional tectonics, which had started duri ng ihe jurassic, init iated upl ifl and altered pallerns of sedimentation. therefore remarkable uncon­ formities occur along th e basin margins in ihe cretai ina-induslrija nane, rese;;lrch & developl11elh, p.o. box 1014, ii r-i 0000 zagreb. croatia. 2 chevron oil field research co., p.o. box 1627. rich mond. ca 94802-0627, usa. present add ress: stanford un iversit y. department of geo­ logical and environmental sciences. stanford, ca 94305-2115, usa. j chev ron overseas petroleum inc., p.o.box 5046, san ramon. ca 94583 -0946, usa . present address: p.o.box ir77. c;'lpitola. ca 95010, usa. i uni versi ty of zagreb. faculty of natural sciences, zvonil11irova street 8/1 1, hr-i 0000 zagreb, croatia. 5 ina-industrija nafte, naft'lplin. p.o.dox 554, iir i 0000 zagreb, croatia. (. chevron overseas petroleum inc., p.o. box 5046, san ramon, ca 94583-0946, usa. present address: arco international oi l and gas co., 2300 wesl plano parkwily, plano, texas 75075-8499, usa. 136 • • • • • 024 a 01s ••• 0'9 ... enlarged area e. ... ... • 022 n a "" . • • 023 geologia cro:nica 49n fig. i sample loca ti on map. legend: • oil we ll s; .... explo ra­ tion we ll s (only the well s subjected ( 0 runher siudy arc add itiona ll y label­ led) . cco us. above the ullcomformities cretaceous flysch deposit s a rc found which cons ist of reworked pelagic material, terrigenous clays and turbidites. shallow mari ne carbonate sedimentation cont inued in the palaeogene only in a small area and was followed by a period of extensive erosion of the mesozoic strata. during the neogene, when compressional tec tonics turned [ 0 an extensional regime, rifting and subsidence took place, associated with taphrogcnic fo ld ing and vol­ cani sm, during the mid-latc miocene, rapid sed imen­ ta ti on accumulated up to 2 km thi ck sequences in the depoccntcrs. frequent vertica l and lat era l fa c ies changes are characteri stic of thesc deposits, mainly due to differences in the geological structures o f o lder sur­ rounding strata which supplied mate ria l to the miocene depressions. the rapid sedime nt ati on las ted until the sample 02 016 019 07 024 08 02 01 03 022 023 physical properties gravi ty, kg/i 0.874 0.871 0.860 0.843 0.877 0.859 0.899 0.951 0.882 0.897 0.870 a pi , a1 15°c 29 3 1 35 35 31 33 27 35 28 26 30 pour poi iii , °c 27 26 30 24 27 30 30 24 2 1 -9 19 isotope depletion bl~c, ppt -25 .6 -25.5 -26.0 -26.4 -25 .8 -26.5 -25.9 -26.1 -24.6 -24.8 -25.3 8 d, ppl 158 160 148 138 14 1 152 143 14 1 154 154 152 elemental composition ii/c 1. 8 1.7 1.8 1.9 1.9 1.9 1.8 1.8 j.7 1.6 1.8 s,% 0.7 0.7 oa 0.2 0.3 0.5 0.6 0.2 0.3 oa oa ni/(ni+v) 0.9 0.8 * • 1.0 0.9 1.0 0.9 1.0 1.0 1.0 grou p composition sat, % 68.0 67.9 72.4 70.7 67.7 65.3 0.53 0.74 60.7 41.8 59.5 aro,% 16.0 17.1 15.0 19.6 24.6 22.2 28.1 17.0 23.7 35.9 24.5 nso,% 12.5 11.0 8.6 7.5 6.3 10.0 14.5 5. 1 13.8 19.3 14.0 aspi-i ,% 3.5 4 .0 4.0 2.2 1.4 2.5 4.4 3.9 1.8 3.0 2.0 gc parameters cpi 0.94 0.96 0.98 0.97 0.98 0.99 0.99 0.99 1.00 ** 0.97 prj phyl 0.89 0.78 0.87 0.99 0.98 0.82 1.00 1.05 1.1 4 0.92 0.96 prjne ,? 0.87 0.68 0.67 0.54 0.66 0.64 0.95 0.63 lao 5.68 0.77 table i bulk properties of the edd and ssd oi ls. legend: :to = no porphyrins: ** = sample biodegraded. abjbeg cl al.: geochernicnl study of oils and oil source rock rrom the eastcm dravn and sinvonija-s rijem depressions .. , 137 >­ fen z w f­ z pr pl iocene when depos its from coarseto fine-grained clastics and pelites were deposited. along the edd and ssd the recent tempera tu re gradients are comparatively high (4-6°c/ioom) proba­ bly as a consequence of a relat ively thin crust and the rifling characteristics of the pannonian basin wh ich is well known for high heal flow (e.g., doyenyi & i-lory krh, 1988). commercial oils arc found in both the edd and ssd. thcy arc trapped in porous and/or fractured reser­ voirs, mainly in the miocene moslavacka gora forma­ tion and in the mesozoic strata, as we \! as in fractured basement. the related source rock has been studied recen[ly (alajbeg e[ al.. 1990; baric e[ al.. 1992; yulama, 1994; hernitz c[ ai. , 1995; baric e[ ai., 1995). thi s paper contributes detailed geochemical data as further evidence of this source rock. 2. experimental data oils os. 016, 019, 07, 024, 08, 02 and 01 from the edd as well as oils 03 , 022 and 023 from [he sdd (fig. 1) were studied for their physical properties: grav ity by astm d 1289 and pour point by astm d 97; e lemental analysis: c , h, s, v and ni; gc data: a b c rete nt ton ttme fig. 2 examples of ihe whole oil gas chromalograms a) 019: unimodal n-alkane dislribulion lite range of the inlensive peaks belongs to n-alkanes; b) 023: bimodal/tri ­ modal n-alkall e distribution [he range of thc intensive peaks belongs to il-alkanes ; c) 0 22 : biodegraded oil sample inten­ sive peaks belong 10 i-alkancs. whole oil gas chromatogram, carbon preference index (cpi) (bray & eyans, 1961), pris[ane-[o-phy[ane ratio (pr/phyt) and pristane-to-normal heptaclecanc rat io (pr/nc 17 ); group composition (t able i): saturates (sat), aromatics (aro), polars (pol) anel asphaltenes (aspi-!) (pet ers & moldowan, [993, p. 54) , as well as carbon and hydrogen isotope depletion (schoell, 1984). t hc oils 0 16, oj 9 anel 024 from [he edd anel [he 022 and 023 oil s from the ssd, which were founel [0 exp ress some differences in bulk properties , were selected for biomarker study; tritcrpancs, stcrancs, and monoaromatic and triaromatic steroids (seifert & moldowan, 1986; peters & moldowan, 1993, p. 151-202 and p. 227-250). cuttings from eight exp loration wells (fig. i) were examined for source rock identi ficatioll. this included total organic carbon (pig. 8), free hydrocarbons yield (s i) ' kerogen pyro­ iyza[c yield (s2)' hyelrogen index (hi~loo s2(foc) and the temperature of the s2-peak maximum (tmax). the organic matter in miocene strata from the exploration well ew (fig. l) was studied microscopically for vitri­ nite retlcctance determ ination (ro). pyrolysis in an off­ li ne lube rcacror (alajl3eg & stipak, 1985) anel gas chromatography of oil asphaltenc pyrolysates was also performed. 138 >­ t: '" z uj t­ z t­ a: ~ c,o 3. results and discussion the study or the genetic relationships among the oils relied on their bulk properties and biomarkers. the edd and ssd oils are found 10 be rather waxy as refleeled in pour points oc up to 30°c crable 1). the exception is the pour point _9°c of 022 which was dis­ covered in a relatively shallow trap (depth <1000 in, trap temperature 65°c) where it underwent biodegrada­ tion. for this oil the biodegradation is confirmed by the high predominance of pristane over n-heptadekane (pr/nci7~5.68). a comparatively low h/c (1.6) and sat­ urates yield (41.8%) as well as in the low intensity of normal alkanes as shown in whole oil gas chro­ rnatogram (fig. 2c). the other oils show an intensive n­ alkanes range, sometimes exceeding n-c3shw arranged in a (rough ly) unimodal distri bution (e.g. 019, in fig. 2a, by biomarkers found to be comparativcly the most mature one) and in a non-unimodal (bimoda!/trimodal) distribution (e.g. 023, in fig. 2b, found [0 be of the comparatively lowest malurity lcvel). almost all the oils show a slight predominance of even n-alkanes (cpr slightly less than one table 1). the aliphatic structure of the studied oils is also reflected in the products of asphajtene pyrolysis (e.g. 019), which are dominated by the series of doublets of n-alkanes and the related l-alkenes (fig. 3) as well as a h/c atomic ratio up to 1.9 (table i). the waxy character and the type or n-alkane distrib­ ution, may indicate that organic matter of algal (or reworked algal) origin served as the predominating oil precursor, which was possibly deposited in carbonateretention time geologia croatica 49/2 fig. 3 gc chromatogram of asphal­ lene pyrolysis products for 019; thc intcnsivc peak doublcts belong to j-alkenes and n-ulka­ ncs, c.g. c ;ij is related lo i-dccenc and c 10 lo n-decane. rich sediments (peters & moldow an, 1993). in those oils where porphyrins are detccted, ni porphyrins are found to predominate strongly over y::::o por­ phyrins, suggesting a suboxic to oxic depositional envi­ ronment of the source rock which released the studied oils (e.g., moldowan et ai., 1986). thi s is also reflected by the low to moderate sulphur content (0.2% to 0.7%) in oils. the ssd oils, in comparison to the edd oils, are found to be isotopically heavier (table 1) and lower iii pour points and h/c ratios. 3.1. biomarker results­ oil/oil correlation for biomarker analysis, 3 edd samples were cho­ sen: 019 as the example which reaches the high pour point (30°c), and high api gravity (33°) and has no measurable porphyrins; 024 as the example which con­ tains no v~o porphyrins [ni/(ni+v)~i)l and reaches high i-l/c ratio (1.9); 016 which is characterized by the lowest h/c ratio (1.7) among the studied edd oils and comparatively high sulphur (0.7%). furthermore 2 ssd oils were taken: the biodegraded 022, and 023 which was found to be similar in physical properties to 03 . the biomarker source parameters for oil-to-oil cor­ relation of the five select oils from edd and ssd indi ­ cate close correlation among the oils. the distributions of c27-c2s-c29 steranes were measured using metastable reac tion monitoring (mrm) gc ms. the steranes mea­ sured include the sum of isomers aaa20s, aaa20r, o:~~20s, o:~~20r, and the measured distributions clusalajbeg ct al : geochemical study of oi ls and oi l sourcc rock rroill the eastcrn drava and slavonijksrijem depressions ... 139 c" legend (:> o ll # 16 t;i o il # 19 a o il#22 fo o il#23 x o il#24 c" c" fig. 4 $tcrane distribu ti on (m/z 21 7) ror se lect edd and ssd oils ; cn = cholestanes; c28 = ergostanes; c29 = stigmastanes. ter in a group indicating the similarity of oil for sterol precursors (f ig. 4, table 2) . steranc distributions refl ect the algal (eukaryoti c) input to the so urce (mackenzie, 1984). the distributions of c 27-c 2s-c29 c-ring monoaroma­ lie stero id s (mas ), including the sllm of isomers 5a20s 5a20r 5~20s 5~20r dia-20r, dia-20s , cluster in a very tight group independently confirming the ste r­ ane results (fig. 5). c-ring monoaromatic steroids are thought to be derived from sterols with a higher degree of unsaturation than is necessary [or the formation o[ steranes with, perhaps, a double bond in the side-chain (c.g. moldowan & fago , 1986; riolo ct ai. , 1986), rellecting precursors other than the stcranes. the leg end (:> o ll# 16 >:'loll # 19 o o il#22 ~ o ll #23 x o ll #24 c'" c" fig. 5 mas distribution (m/z 253) for select edd and ssd oi ls; cn = cho lestane type ma steroids; cn = ergoslane type ma stero ids ; c2~ = stigmastane type ma steroids. steranes and mas together indicate that the three edd oils and two ssd oils examined were very probably genera ted from the same source. homohopane concentrations in the different oils fol ­ iowa similar pattern (fig. 6), decreasing with increas­ ing c-number. th is obscrvation togcther with a signi fi ­ cant preference for the c32 homolog, suggcst a mildly suboxic environment of deposition [or the source rock (moldowan et ai. , 1992). 24-n-propyl choles tane was de tected by (mrm) gc ms (fig. 7) indicating marine al gal input typical ly associated with a marine deposi tional environmenl (moldowan ct ai. , 1990). low gammacerane indi ces [100 x gammace rane/17o., 2 1~ (h) hopanel suggest that the source rocks were source parameters sample steranes ma steroids a b a b c a b c 016 0.39 0.37 0.24 0.2 1 0.45 0.34 0.72 8.7 0 24 0.35 0.41 0.29 0.21 0.48 0.31 0.74 6.7 019 0.34 0.43 0.23 0.23 0.46 0.32 0.93 b. ! 022 0.37 0.39 0.24 0.23 0.45 0.32 1.08 7.4 0023 0.39 0.33 0.28 0.21 0.46 0.33 0.95 10.2 maturity parameters sample ts/(ts+tm) c"homohopane stigmastane t as,,/( t as'8+ mas,,) 22s/(22s+22r) 20s/(20s+20r) 016 0. 35 0.58 0.46 0.88 024 0.38 0.56 0.45 0.82 019 0.41 0.57 0.5 i 0.94 022 0.42 0.56 0.43 0.89 023 0.33 0.54 0.29 0.85 tab le 2 biomarker parameters for the eod and sso oils. legend: j\ == gammaeerane index; 13 = c35 homohopane index; a = cn / lcn cn : b = c2~ / l cn cn ; c == c29 / lcn c29· 140 50 40 legend () oil# 16 d oil# 19 0 oi l # 22 <$ oil # 23 x oil # 24 10 o+-----~------~------~-----c31 c32 c33 c34 c35 homohopane (22s+22r) fi g. 6 homohopallc dislribulion fo r sc lec l edd and ssd oi ls. deposi ted at normal or reduced, rathe r than elevated marine salinities. predominating ni porphyrins also show that oxy­ gen was ava ilable during early diagenesis (lewan, 1984; moldowan et ai. , 1986; barwise, 1990). oleanane as the possible indicator of terrestrial plant in put to the source (after angiosperms appearance in cretaceous) was not found in significant concentrations > i­ ui z uj i­ ~ geologia croatica 49/2 in any of these oils. low rearranged to normal slerane ratios r j3 ~, 17a(h), 20s + 20r]/ r 14a, 17a (h), 20s + 20r + 14~, 17 ~(i-i) , 20s + 20r], point to a carbo nate mineral matrix for the sou rce rock (moldow an & fago, 1986; mello et ai., 1988; peters & mol­ dow an, 1993). biomarker maturity paramete rs (table 2), which refl ec t thermal transformations of biomarkers, inc lud­ ing ts / (ts + tm) , the isomer ratios of 22r / (22r + 22s) and 17~, 2ia(h) /17a , 21~(i-i) configurations in hopanes (i .e., moretancs/hopancs) and 14a, 17a(h) / [ 14a, 17a(h) + 14~, 17~(h)j and the 20r / (20r + 20s) configurat ion in c29-steranes as well as s teroid aromati­ zat ion were used . the 22s / (22s + 22r) holllohopane ratios between 0.5 5 and 0.60 suggest full epimcriza tion and that the oils are morc mature than the initial genera­ tion stage (seifert & moldowan, 1986). i-iowev­ cr, the sterane isomerizat ion parameters are less than fully equilibrated suggesting that generation occurred before the peak of the oil window (peters & mol­ dow an, 1993). regarding the biomarker parameters the maturity level of the oils studied [or biomarkers can be ranked in the fo llowing order: 0 23 < 022, 016 and 0 24 < 019, where 0 23 was generated in the late early oil window and 019 was generated near peak. hi gh temperature gradients improved the maturity rank qf the edd and ssd oils. 3.2. source rock study in ord er to identify the oil so urce rock, cuttings from eight wells (fig. i ) were studied . the organic matt er from the ex p lorat ion well ew underwent addi­ tional s tudy as the reprcsentat ive sam pl e. in ew the miocene st rata between 2,400 m and 2,680 m arc found to be a so urce rock, with average toc valucs ranging from 0.5 % to 1 %. hydrogen indices range up to 475 in retention time fig . 7 mass fragmell !ogram m/z 414 ~ 2 17 from melaslable gc ms analys is for an edd oil showing a dislribulion of 24-n-propylc­ holcslanes . ahjbeg el '1 1 . gcochcmic:ll study of oi ls .mel oi l source rock from the e:lstem dr:jy ;j and slavon ij:l"srijem depressions .. '"' well toc 5, hi mg/g toc t max vitrinite reflectance data % mg/g 5,.100 / toc °c %ro depth w w z z z 0 m 0 0 oc w >= oc " a. oj .. >-i i a. w (f) .. ::e ocoj oj -' >< .. oc wi (5 :ie 0 >i oj ... " " " i.' i.' " '" ... 3" '" '" .. , ... ". '" 0.3 0.6 1.0 2.0 3.0 • , • w z w " 0 ... 500 on ......... ! w " -' ~ z a. 0 w -' z w " 1000 0 :j , .. a. 1500 " ...... '" on 0: 0 " 0 -' cd 2000 w ..... . .. , .... . . ..... z w .~. " 0 ovanle ~. :;; ivanic "'" · grad 2500 ~ ,~ l! · --::; } >" :50: "§ · ono 3000 0" " ... z w " 3500 w .... .. .. on " '" 4000 .. . fig. h geochem ical log o f ihe cxptor<u ion we ll ew' sia l' • thc kril.cvc i r ollll:lt ion. the deeper pan of the source rock (fig. 8; krilcvci clan ill mos lavacka gora formation) and refl ec t the predom­ inating oil -prone characte r of the kerogen (type ii ). in overl ying strata , organic matte r turned to mixed oil/gas prone (type ii/ ill) and then to gas prone (type ill) in the ivanic grad formation. regarding the fac t that the sediments o f th is interval are predominantly represented by clasti cs, the change mi ght reflec t the upward increasin g input of non-oxi­ di zed te rrestrial maceral s. however, some c lasts of these c lastic sed iments were reworked from older for­ mati ons and they may contain variolls types of organic matte r of different diageneti c and thermal hi story. the non -uniformity of lhe organi c facies was re fl ec ted in three recognizable vitrini te popu lations: aut ochthonous v itrinit es, the values of whi ch increase with depth cr able 3) in accordance with the geothermal gradient ; vitrini tcs with refl ectance values indicating they might have been earlier diagenclicall y (primarl y) partl y oxi ­ di zed o r secondarily rcworked; and vitrinit es with re fl ec tance va lues whi ch 1110st probably represent grains from older, reworked formations. the miocene source rock is al so found in other ex ploration wells . mesozoic stra ta arc irregul a rl y d is142 depth populations (01 ) l si 2nd 3rd 2380 0.522 0.965 2.021 2480 0.509 0.955 1.868 2580 0.538 1.039 2.1 19 2680 0.557 1.018 1.909 2780 0.572 1.048 2.016 2880 0.566 1.057 2.025 2970 0.609 1.075 2.01 2 table 3 vitrinite rcocclanccs for organic matter in miocene sirala in the we ll ewo tributcd in the edd ancl in ssd, and they a fc poor in organic maher. 4. conclusion geochem ical evidence suggests that edd and ssd oi is have been generated from the same source rock, deposited in a carbonate mineral matrix under marine suboxic condi tions. the oils were generated at the early to 111idcl lc maturity stage of the source. diltcrcnccs in oil properties should be ascribed to different migration and trapp ing hi sto ries or different maturity levels al variolls locations. a miocene source rock is identified conta ining autochthonous and all ochthonous organ ic matter, pre­ dominant ly type it/ itt. mesozoic strata are found to be abse nt and with no recent oil gcnerating potential. thus, the miocene appears 10 be thc onl y cons istent source throughout the edd and ssd that can account for the commcrcial oil in this basin. becau se of the modest prolificity of th is source, a rather efficient trap­ ping system is post ul ated, including short mi gration distances and good cap rocks , in order to accou nt for the known oil acc umulations. these cond itions are con­ sistenl with ihe geology of ihe edd and ssd. acknowledgement the authors are gratefu l to the management of rna and chevron for approving the publi cation of these data, and they arc grateful to the colleagues who coop­ erated during this project, includ ing p. sundarara­ man, k.e. peters, s. svel-cerovecki, i. leb inec, c.y. lee, m.m. pena, l.a.wraxall and g. koch. 5. references alajbeg, a., britvlc, v., svel-ceroveckl, s. , corn ford, ch., todorlc, a" ra1kovlc, 1., baric, g. & putnikovic, a. (1990): geogcolog i:l croatica 49(1 chemi cal st udy of the oi ls and source rocks in the pannonian basin.org. geochel11 ., 16,339-352. alalbeg, a. & stipak, b. ( 1985): thermal dccom­ position of polystyrene foam under cont rolled atmosphere and temperatu re conditions.j. ana !. appj. pyroj., 7, 283-306. baric, g., hernitz, z. & vellc, 1. (1995): source rocks and oils and gases of eastern part of the drava deprcss ion (easlern croali a).in: vlahovic, i. , vellc, l. & sparica, m. (eds.): firsl croali an geological congrcss, abstracts, 12, zagreb. baric, g., mesic, i. & jungwirth , m. ( 1992): sedimentary and geoc hemical charac teristics of rocks and fluids of wes tern part of the drava depression.naha, 43, 225-238, zagrcb. barwise, a.j.g. ( 1990): role or nickel ancl vanadi­ um in petroleum class ification.energy and [-'ue ls, 4,647-652. bra y, e.e. & evans , e.d. (1961): distribution or n­ paraffins as a clue to rccognition of source beds.­ gcochim. cosmochim. acta, 22, 215. dovenyi, p. & horv ath, f. (1988): a revi ew of temperature, thermal conduct ivit y and heat flow data fro m the pannonian basin. aapg mcmoir, 45,171-182 . hernitz, z. (1983): dubinski struklurllo-ieklonski odnosi u poclrucju istocne siavonije.unpubl ished ph.d. thesis, 22 1 p. , university of zagreb. hernitz, z., velic, j. & baric, g. ( 1995): origin of hydrocarbons in the eastern part of the drava depression (eastern croatia).geo!. croal. , 48/1, 87-95. lewan, m.d. (1984): factors conlroll ing the propor­ tionality of vanad ium to nickel in crude oils.­ geochim. cosmochim. acla, 48, 2231 -2238. mackenzie, a.s. (1984): appl icalion or biologica l markers in petroleum chemi st ry.in: brooks, j. & welte, d.h. (eds.): advances in pctroleum geochem islry, 1, 115-214, academi c press, lon ­ don. mello, m.r., telnaes, n. , gaglianone, p.c., chicarelli, m.l. , brassell, s.c. & max­ well, 1.r. (1988): organic geochemical characlcr­ ization of depositional paleoenvironments in brazil ­ ian marginal basins.org. geochem. , 13,31-46. moldowan, j. m. & fago, f.j. (1986): siruciure and sign ificance of a novel rearranged monoaromat­ ic steroid hydrocarbon in pet roleum.gcochim. cosmochim. acla, 50, 343·351. moldowan, j.m., sundararaman, p & sc hoell, m. (1986): sensilivity or biomarker properties to depositiona l enviro nment and/or source input in the lower toarc ian of sw -ger­ many.org. geochem., 10,915-926. alajbcg ct al.: gcoehcm ie<ll study of oils and oil source rock from the eastern drava and slavonija~srijem dcprcssiom ... 143 moldowan, lm., fago, fj. , lee, c. y. , jacob­ son, s.r. , watt, d.s., slougui, n.-e., jeganathan, a. & young, d.c. (1990) : sedi­ mentary 24-n-propylcholes tanes, molecular fossils diagnostic for marinc algae.seiencc, 247, 309-3 12. mold ow an, j.m., lee, c.y., sundararaman, p , sa lvatori, '1'. , alaibeg, a. , gjukic, b., demaison, gj ., slougui, n.-e. & watt, d. s. ( 1992): source correlation and maturity assess­ ment of selecl oils and rocks [rom the central ad ri­ atic basin (ita ly and yu goslavia).in: moldo­ wan , j.m. , albrecht, p. & philp, r.p. (eds.): biological markcrs in sediments and petroleum, 370-40 1, prentice hall , englewood cliffs. pam le, j . (1986): granite-mctamorphic complexes in the basement of the pannonian bas in between the rivers sava and drava (based on data of deep oil borehol es) .proceedi ngs of xi congr. yu gos l. geolog., tara, 259-272, belgrade. pandzic, j. (1986): prcdtcrcijar jugozapadnog dijela panonskog bazena (geology of the pre -tertiary base of the so uthwestern part of th e pan non ian basin).ina-naftaplin , zagreb, 183 p. peters, k. e. & moldowan, j.m. ( 1993): the biomarker guide.prentice hall , englewood cli tis, 362 p. riolo, .i., hussler, g., albrecht, p. & con­ nan, j. (1986): distribution of aromatic steroids in geol ogical samples : their evaluation as geochem ical paramelers.org. geochem., 10, 98j-990. royden, l.l-t. & horvath, f. (eds .) ( 1988): the pannonian bas in, a st udy in basin cvo lution.­ aapg memoir, 45, 394 p., aapg, tulsa and hun­ gari an geol. soc., budapest. schoell, m. (1984) : stable isotopes in petroieuill research.in: brooks, j. & welte, d.h. (eds.): advances in petroleum geochemistry, 1,215-245, academic press, london . seifert, w.k. & moldowan, j.m. (1986): usc of biologic al markers in petroleum exp loralion.in: johns , r.b. (ed.) : methods in geochemistry and geophysics, 24, 261-290, elsevier sci. pubs. , ams­ terdam. vulama l. ( 1994): source roek potential ai the east­ ern drava depression and some other sourcc rock loca liliti es in croat ia as cvaluated from well log data. geo l. croat., 47/2,205-2 14. manuscript received january 10, 1995. revised manuscript accepted september ii, 1996. '4' geologia cromica 49(2 geologia croatica 45 95 -114 6 fig. 3 pl. zagreb 1992 udc 553.492.1:551.736 (497.13+497.15) scientific paper upper permian evaporites and associated rocks of dalmatia and borderline area of lika and bosnia ante šušnjara1, kr~imir sakač2, bogomir jelen3 and anto gabrić1 key words: dal matia, lika, bosnia, evaporites, gypsum, anhydrite, clastics, carbonates, volcanites, palynomorphs, upper permian in the region of central and north dalrnatia, as well as in the southeastern lika and western bosnia, the evaporite complex composed mainly of gypswn and anhydrite and associated rocks: clastics, carbonate and somewhere volcanites have been investigated. the lithological and petrographical characteristics of these sediments, their interrelationships and relations with mesozoic, paleogene and neogene strata have been shown. also, the palynological analyses prove upper perm ian age of the cvaporite complex for the first time. this conclusion has been supported with the geochemical and mineralogical data as well. l. introduction in middle and northern dalmatia, and in the bordeline area between lika and bosnia (fig. l) a detailed geological investigation of evaporites (gypsum and anhydrite) and associate deposits of upper permian was carried out also, numerous localities in sw bosnia and, partly, herzegovina have been surveyed (fig.5). this investigation, in which numerous experts from various institutes took part. is shown in three annual reports and in a final study: "geological investigations of the evaporites and associated deposits of dalmatia, lika and south-western bosnia and herzegovina" carried out by the institute of geology. zagreb for the company "ina-naftaplin research survey", zagreb. the aim of these investigations was to determine the age of evaporites and associated deposits, their mutual superposition and tectonic relations, and to indicate the possible position of evaporites in the structural complex of the investigated part of the dinarides with regard to the tectonic evolution. with these investigations pctrographic, 'llineralogical and chemical characteristics of evaporites and associated upper perm ian rocks were determined, as well as the type of environment and conditions for their sedimentation . the solution of the above geological problems required a complex approach. for this purpose a geological map was produced, scale l :25.000 surface approximately 500 km1 (fig. i) an area with outcrops of the investigated upper pennian sediments 1institute of geology, sachsova 2, zagreb, croatia "croatian museum of natural hystory, demetrova l, zagreb, croatia 'geological institute, dimičeva 14, ljubljana, slovenia ključne riječi: dalmacija, lika, bosna, evaporiti, gips, anhidrit, klastiti, karbonati, vulkani ti, palinomorfa, gornji perm u srednjoj i sjevernoj dalmaciji, jugoistočnoj lici i zapadnoj bosni istraži van je evaporitni kompleks koji se sastoji od gipsa i anhidrita te pratećih stijena: klastita, karbonata i mjestimično vulkanita. prikazane su litološke i pctrografske karakteristike ovih naslaga, njihovi međusobni odnosi te odnosi s mezozojskim,u paleogenskim i neogenskim sedimentima. palinololkim analizama prvi put je doka:una gomjo· permska starost evaporitnog kompleksa ito potvrđuju geokemijska i mineralolka istraživanja. which encompassed the remaining deposits with which they are in contact. this geological map, of which two sections are shown here as an illustration of the determined geological relations (fig. 2,3), was produced by k. sakač, a. šušnjara, a. gabrić, v. pencinger and b. lukšić. numerous detailed gcological columns of the clastic upper permian deposits were recorded during field investigations. extensive sedimentological, petrographic, paleontologic and geoochemical investigations were carried out on a large number of co!jected selected samples. aerial and satellite photographs were analysed, and with a representation of the already existing geophysical maps and seizmic profiles, a review was made of the possible position of evaporites in the whole structural-tectonic complex, during which a new classification of the faults and other tectonic elements of regional importance was made. in this work only a part of the results of the above investigations is presented. they refer to the lithological and petrographic characteristics and to the age and mutual relations of evaporites and associated upper permian deposits. the results of the other investigations will be presenled in separate works. this work partly incorporates the results given in annual reports on microscopic investigations of the composition and structure of rocks carried out by b. šćavničar, j. tišljar, al. šimunić and s. novosel-škorić, and also isotopic a~alyses of sulphur from evaporites by t. dolanc and j. pezdić. 96 palynological examinations were carried out by b. jelen. 2. review of former investigations on evaporites in the middle part of the dinarides numerous authors have studied the stratigraphic and tectonic position and general characteristic of evaporites and associated rocks in the middle part of the dinarides. the differences in age which appear in these works occurred because of the lack of reliable paleontological documentation and the complex tectonics of an area with evaporites. r)eierle(1862), hauer. (1868) and mojsisovics et al. (1880) were the first to present the data on evaporites in the above region. they classify them, together with associated carbonate and clastic deposits, in the "werfenian" deposits of the lower triassic. at that time such an opinion was also accepted by other authors, for example, st ache (1889), kerner (1901, 1916,1920), koch (1914 a, b), and schubert (1920). they showed distribution of gypsum in the interior of dal matia and lika in more detail. th us gypsum is classified as the perm ian in age and associated clastics as lower triassic in age. at the same time franić (1900), kispatić (1901) and suklje (1914) described the significant occurrences of gypsum in the surroundings of srb in lika. katzer (1903,1921,1925) was the first one who described in more detail the gypsum beds in bosnia and herzegovina. he considered that they were permian jr age. podubsky (1963,1976) analysed in more detail the beds of these evaporites. he believed that the evaporites were sedimented in the permian in an epicontinental and not in a lagoonal environment, and that the sedimentation continued in the lower triassic with the deposition of carbonate rocks and clastics. later ćićić (1987) proposed the permian age of gypsum and anhydrite beds of bosnia and herzego,vina, i. e. former yugoslavia. this was in accordance with the data of several authors. as the above investigations did not provide any direct evidence of the age of the evaporites, a dilemma appeared with regard to their stratigraphic position, when, while drilling in the adriatic area, anhydrites were found within the uppertriassic deposits (island of krk), i.e. jurassic and cretaceous (dugi otok, olib, brač, montenegrian coastal region, which was reported by ćanović (1969), bos kov-štajner (1971),kranjec (1979), durasek et al. (1981), blasković (1983)andothers. in an attempt to connect the stratigraphic position of evaporites from the adriatic area with those in the interior of the middle part of the dinari des s us njar et al.(1965), susnjar & bukovac (1978, 1979) and susnjar (1981, 1983) presented a different interpretation of the paleogeographic relations in the mesozoic with partial alternation of tbe stratigraphic sequence of individual deposits and their tectonic position along the una valley and part of the middle dal matia. thus, evaporites and associated clastic geologia croatica 45 sediments of this area were classified in the malm, others would correspond to the transition of the malm into the lower cretaceous (osredci at srb), i.e. to the transition of the lower into the upper cretaceous (martin brod in the una valley). however, investigations of the other authors supported earlier opinions on the perm ian or perm ian-triassic age of evaporites. consequently, iv anović et al. (1971) in an analysis oflithological characteristics of evaporites o , 2 figs. la and lb. areas of investigation. slike la i lb. područja istraživanja explanation of symbols: legenda: l. neogene deposits neogenski sedimenti fl g. slik• 1· a 1) n 1~ 2 ~ 3 !::;~:!;!:;:;:;~::::~ 2. mesozoic and paleogene deposits mezozojske i paleogenske naslage 3. -upper pennian deposits, partly covered with quatemary formations gomjopennske naslage, djelomično pokrivene kvartamim tvorevinama 4. situation of figs. 2 and 3 položaj slike 2 i 3 5. po ll en analysis sites nalazišta pole na šulnjara, sakač, jelen &. gabrić : upper perm ian evaporites ... and clastics in middle dalmatia found that they belong to the interval of the upper permian lower triassic. sakač et al. (1970) found in the top part of clastics paleontological evidence of the lower triassic fossils. herak (1973, 1983) refused the above opinion on the mainly malm age of evaporites in the cited area of dal matia and lika and considered the possible conditions of their deposition in the lagoonal environment during the upper perm ian or perm o-triassic, and emphasizes their importance in the tectonics, as they are situated mainly on the overthrust fronts in tectonic windows, etc. in the same way chorowics (1975, 1977) flg . 1 b slika • 97 interpreted the position of evaporites along the regional dislocation karlovac-knin. hc found new important details, such as the overthrust of the triassic deposits of stražbenica, the tectonic window of suvaja, and other complicated tectonic relations in a wide area at srb. barun (1985) classified evaporites in the same area in the permo-triassic, referring to the extensive jelar deposits as an indicator of the complex tectonic movements in the tertiary. opinion on the "perm o-triassic" age of evaporites and associated carbonates and clastic rocks prevailcd during the production of detailed geological maps in 98 geologia croatica 45 parts of dal matia, lika and western bosnia, except from the wider area of srb (grimani et al., 1972, 1975; iv anović et al., 1977, 1978; papeš et al., 1982; raić et al., 1984). is important, differs from the anhydrites from the deep drill-wells from the adriatic coastal and island area. this justifies the claim of more phases of evaporitic sedimentation in that part of the dinarides. šiftar (1982, 1986) on the basis of isotopic analyses of sulphur from gypsum from the surroundings of sinj, and the una valley, suggests their permian and permo­ triassic age. the isotopic value of the deposits, which fig. 2. geolog ic map of the sinj area. further investigations of evaporitcs and associated rocks which followed providcd new elements for the interpretation of sedimentation regime during the upper permian and lower triassic. data in this connection slika 2. geološka kana okolice sinja. explanation of symbols for figs. 2 and 3: legenda za slike 2 i 3: l. alluvial deposits aluvijalni nanos. 2. deluvial deposits deluvijalni nanos. 3. fluvioglacial sediments. quatcmary. fluvioglacijalni sedimenti. kvanar. 4. -fresh-water deposits; maris and limestones. miocene. slatkovodne naslage; lapori i vapnenci. miocen. 5. non-bedded polymict breccia (jelar deposits). late paleogcne. ncuslojcnc polimiktne breče (jclar naslage). mlađi paleogen. 6. limestone, dolomite, and carbonate breccia. upper crctaccous.vapnenci, dolomiti i karbonatne brečc. gornja kreda. 7. limestone and dolomite. lower cretaceous. vapnenci i dolomiti. donja kreda. 8. limestone and dolomite with chen (lemeš deposits). malm. vapnenci i dolomiti s rožnjacirna (lemeš naslage). malm. 9. limestone and dolomite. malm.vapnenci i dolomiti. malm. 10. limcstone and dolomite. doggcr. vapnenci i dolomiti. doger. 11. limes tone and dolomite. lias. vapnenci i dolom iti. lij as. 12. limestone and dolomite with clastic intercalations. ladinian. vapnenci i dolomiti s ulošcima klastita. ladin ik. 13. limestone and-dolomite with clastic intercalations. anisian. vapnenci i dolomiti s ulošcima klastita. anizik. 14. -carbonate deposits. upper scythian karbonatne naslage. gornji skit. 15. clastic and carbonate sediments. lower scythian. klastični i karbonatni sedimenti. donji skit. 16. porous carbonate breccia ("rauhwac:ke"). permian, prc-neogene, and quatemary. šupljikave karbonatne breče ("rauhwac:ke"). perm, predneogen i kvanar. 17. clastic deposits: pelite, siltite, and sandstone. upper permian. klastične naslage: peliti, siltiti i pješčcnjaci. gornji perm. 18. limestone and dolomite. upper permian. vapnenci i dolomiti. gornji perm. 19. • evaporites: gypsum and anhydrite. upper perm ian. evaporiti: gips i anhidrit. gornji perm. 20. albitized basic igneous rocks. upper permian? albitizirani bazični eruptivi. gornji perm? 21. dip-strike symbols. elementi nagiba sloja. 22. geologic boundary: l normal; 2 gradual transition; 3 transgressive. geološka granica: l normalna, 2 postupni prijelaz, 3 transgrcsivna. šulnjara, sakač, jelen & gabrić : upper perm ian evaporiles ... 99 ,d 11 f-%. ~ 2 d 12~ 3 ~ 13 e::a 21g .. ~ 14 tl!l1 22@$il 5 ~ 15~ 23 ~ eeffil 10 ~~~j 24~ 7 fffi±l 172si~.:j ~ 18~ § l 28 ~~~ 10 ~ 21g 10 gj-:;:1 20 § o 0.1 h• fig. 3. geologic map of the una river spring area. slika 3. geolofka karta lireg područja oko vrela une 23.geologic boundary, approximalely localed (l normal, 2 graduallransilion, 3 lransgressive). geololka granica aproksimalivno locirana (t normalna, 2 poslupni prijelaz., 3 11llllsgresivna). 24. faulu (l normal, 2 revene). rasjedi ( l normalni, 2 revenni). 25. faulls (l normal, 2 revene), approximately localed or assumedras jedi (l normalni, 2 reversni) aproksimativno locirani ili prelpostavljeni). 26. overthrusl conlacu (l established; 2 approximalely localed or assumed). -nav lačni konlakli (l ulvrđeni, 2 aproksimalivno locirani ili prelpostavljeni). 27. pollen analysis s iles. nalazilta polena. 100 can be found in the works published by šća vnićar (1973) on the finding of moulds of balite crystals in clastics of the permian at vrlika and knin, šušnjara (1974) on the permian-scythian pelites, skeru (1974) on the gypsum bed at sinj, and šća vnićar and šušnjara (1983) on the geological column of the lower triassic deposits at muć, not far from sinj. thus, certain questions are being gradually solved in connection with the upper permian evaporites in the middle part of the dinarides. 3. the distribution of ev apo rites and associated sediments detailed geological investigations have included sites with evaporites and associated deposits located between sinj and kulen vakuf (fig. 1). they are exposed mainly in the morphologically lower parts of the sites, karst po ljes and valleys. evaporites and associated sediments are the oldest deposits of the area. they are widespread near sinj (glavica, karakašica, suhač, krin), and vrličko, petrovo, kosovo and kninsko polje. the foregoing areas almost entirely consist of evaporites and associated deposits, although they are largely covered with quatemary sediments. in the eastern part of petrovo polje neogene deposits are developed, lying on evaporites, which was determined by drilling. a continuation of the evaporite complex from the kninsko polje towards the north can be detected from a series of intermittent occurrences at mračaj b utišnica valley and lička kladrma to dugo polje, and thereafter the zrmanja valley and at bender. in the butišnica and zrmanja valleys (near prevjes) at several places gypsum and anhydrite were drilled. in the una valley they are widespread from podklanac on the south from srb to brotinja and at carev brod and doljani. at martin brod the outcrop represents gypsum and a narrow zone of clastic sediments occur intermittently in the una valley downstream towards kulen vakuf. in the area of kulen vakuf-orašac numerous gypsum outcrops have been exposed and in some places they are clastics. slightly more north from orašac, near v mograč, a zone of evaporite and associated deposits ends. a small gypsum outcrop occurs at bihać, between sokolac and dobranica, although that area has not been included in detailed investigations. in the area of sw bosnia and herzegovina, the evaporite complex iscropping out at numerous localities (fig. 5), but these have not been investigated in detail. only some of them have been briefly surveyed. 4. lithological and petrographic characteristics of ev aporites and associated deposits of the upper permian period the upper permian contains evaporites, clastics and carbonate sediments, to which numerous smaller occurrences of eruptive rocks are connected. the evaporites are represented as gypsum and anhydrites. carbonates are represented by dolomites, limestones geologia croatica 45 and carbonate porous breccias ("rauhwacke") and clastics by pelites, siltstones and sandstones, very rarely by conglomerates. 4.1. ev aporites: gypsum and anhydrite in the karst poljes and valleys evaporites are very widespread. they appear as a series of larger and smaller outcrops in the form of gypsum cliffs, small hummocks, plateaus, etc., over the whole of the investigated area. furthermore, numerous shallow drill-holes, village wells, drainage canals, etc., directly underneath a quaternary cover, enter into the gypsum. also, several drill-holes through the neogene deposits entered tm evaporite deposits. it can be concluded with some certainty that the large part of petrovo, kosovo and vrličko polje, and a part of kninsko polje, the valley in the vicinity of srb, the area ofrajinovac and orašac at kulen vakuf and the vicinity of sinj, consist of evaporites. the deepest drill-bole in evaporites was drilled in 1937 in petrovo polje. it went to a depth of 180 metres and remained in anhydrites. from numerous drillholes, and in gypsum quarries, it can be seen that there is gypsum in the surface area up to a depth of approximately 20-40 metres, and deeper it gradually passes into anhydrite. this clearly shows that the primary deposits of evaporites were anhydrites, and that in the surface conditions of hydratization they pass into gypsum. also, in microscopic slides the numerous specimens of the different stages of hydratization of anhydrites in gypsum can be seen. the deposits of calcium sulphate are stratified and intensively folded. the colours are from dark-grey to light-grey and white. they always contain intercalations and laminae of dolomicrites, which are significantly more frequent in the top part of evaporites. scattered carbonate grains are found in gypsum. clayey components are frequent and organic substances with pyrite are present. because of the alternations of grey, light-grey and white intercalations, the gypsum exhibits a handed texture. the gypsum is coarse grained to fme grained crystallised, and characteristically has a fibrous structure. most frequently there are elongated fibrous grains or crystals without terminal planes, which mutually intergrow one into the other. more rarely regular crystals of gypsum appear. in places, large colourless crystals of gypsum can be found. the following mineral parageneses are characteristic for evaporitic facies: anhydrite,gypsum, dolomite, organic substance, and, as accessories, authigenic pyrite, quartz, bari te and celestine. fragments of carbonate rocks are frequently found in evaporites, and rarely clastic and eruptive rocks. 4.2. limestones and dolomites the largest occurrence of limestones and dolomites can be found in glavica, not far from sinj. small occurrences are found in other areas around sinj, vrlika and in petrovo polje. they are mainly associated with porous breccias. dolomites alternate with evaporites or they are found šulnjara, sakač, jelen & gabrić : upper permian evaporites ... as intercalations in limestones.their colour is ash-grey to black. they belong to early diagenetic criptocrystalline dolomites (dolomicrytes). they always contain organic substance, and fine crystals of authigenic quartz can be observed. limestones are also characteristized by good stratification, and in places by lamination. their colour is grey, dark-grey and black from an admixture of bituminous substances. they are often crosscutted with white calcitic veins. in the area of labrović (near sinj) and umljanović (near drniš), beautiful fluorite crystals are located in limestones in white calcitic veins. barić (1969) linked the genesis offluorite from the sinj region with eruptive rocks. the structure of the limestone is microcrystaline. they are rarely affected by dolomitization. in places they contain authigenic quartz with well developed idiomorphic crystals and clear terminal surfaces. poorly preserved fragments of thin mollusk shells can be seen in limestones. 4.3. porous carbonate breccias carbonate porous breccias, in older literature known by the name "rauhwacke", are connected with the evaporitic complex of deposits. in the investigated area they are abundant. they are most numerous in kosovo polje and at sinj. they are of a small thickness, although in places this thickness is maybe over 30 meters. they are always non-stratified. in places they occur as greater or smaller weakly connected blocks, while in other places they are connected in a very fum rock. in places they appear like dross. the colours are most often brownish or dark-grey. they are characterised by numerous small holes up to 2 cm which are often level surfaces or a system of unevenly formed small channels. in the fme grained calcareous matrix, often spongy to honey-combed pattern (tofa-like) calcareous and dolom i tic fragments are found of sometimes unclear forms. in places dolomitization of irre gular forms in the cement and fragments can be seen, which increases the breccial appearance of the rock. breccias are partially silicified. fragments of rocks in the breccias are most frequently angular, and rarely sub-rounded, and usually unsorted. fragments and blocks of rock in the breccias usually originate from the pennian limestones and dolomites. possibly, a part of the fragments originates from the base of the lower triassic deposits which can be found in podkonje and on milića glavica. fragments of the permian clastics have been determined, as well as few fragments of igneous rocks and gypsum. on the breccias one can find rare fragments of the upper mesozoic and paleogene rocks, most often cretaceous limestones which are not a pri mary content of these deposits. fragments of younger rocks are deposited in breccias entirely by fissures or during the sedimentation of breccias. 4.4. clastic deposits: pelites, siltstones and sandstones a large and entire zone of exposed clastics is located in the eastern part of the kosovo polje, vrličko polje 101 at garjak, in petrovo polje and in suhač at sinj, at srb and on ćulumak in rajinovci, and numerous smaller occurrences over the whole of the investigated area. clastic deposits are usually well stratified; the only slightly poorer stratification can be seen in pelites at garjak. they are very folded and the microfolding is especially marked, which is to be expected because of the type of the deposits and very significant tectonic events in this area and the influence of diapirism. clastics are represented by pelites, siltstones and sandstones, and very rarely conglomerates. in the series of clastic deposits pelitic sediments are dominant. sandstones are more frequent in kosovo polje and at srb than in other areas. clastics are calcareous in some places. the colours are red and grey to grey-greenish, and in places, such as in suhač (a new cut) at sinj and ćulumak near kulen vakuf, they are dark-grey to black. in the whole area they are dominantly red and frequently there are alternations of red and grey. the anal yses show that red and grey clastics have an almost identical mineral composition. the differences that can be seen in the colours are probably the result of conditions of sedimentation, and the different oxidational state of the iron in the minerals which are in red varieties of haematite and goethite, and in grey, pyrite. by special analyses of microelements it was also determined that in the red varieties there is an excess of manganese and in the green varieties, chromium. it would lead to the conclusion that the red clastics are deposited in an oxic environment, and the grey and dark-grey in a more reductive environment with the presence of an organic substance. pelites, besides the basic component clay minerals: illi te, montrnorillonites, kaolinites and hydromuscovites, usually contain calcite, chlorite, muscovite, feldspar and fine grains of quartz also. in pelites, fme larnellar cleavage and parallel stratification, because of planar arrangement of the lamellar minerals, are marked. they often belong to carbonate shales. in siltstones, and particularly sandstones, a content of clayey component decreases, and the participation of silto-psamitic terrigenous detritus increases: quartz, feldspar, muscovite, chlorite and particles of rocks (microquartzite, quartzose schists, etc.). sandstones have a high content of quartz which usually exceeds 75% of the total detritus present. a dominant type of cement is chemogenic quartzose cement, while the matrix of detrital origin is rarely found. sandstones are rarely represented by types of grauwacke (quartzose, feldspathic and micaceous). often, they are subarkoses (quartzose and micaceous), and quartzareniteand quartzlithoarenite. these types of sandstones indicate a connection with the highest levels of the gr<xlen facies from other areas of the western dinarides. the composition and characteristics of the heavy minerals point to this connection even more, and the following minerals have been determined: pyrite, goethite, haematite, zircon, tourmaline, rutile and apatite (iv anović et al., 1971). in clastic rocks authigenic carbonate minerals are 102 often present in variable a.mounts (mainly calcite, sporadically dolomite). calcite is fine grained and most frequently evenly scattered in the primary matrix. a small amount of quartzose conglomerates was fow1d in kosovo polje at milić glavica and in orašac at kulen vakuf. this connection between the described clastic rocks and the evaporitic facies was also indicated by the moulds of balite crystals which were found in these deposits at several places in sinjsko, vrličko and kosovo polje, as well as in the una valley (šća vnićar, 1973). 4.5. albitized basic eruptives although the small outcrops are the most frequent in the investigated area, numerous occurrences of eruptive rock surfaces have been discovered from several tens to several hundreds of square meters. some of these occurrences were not registered earlier. as previously mentioned they are connected exclusively to the upper permian evaporitic complex of deposits. igneous rocks in this area were first mentioned by for tis (1774) and thereafter by hacquet (1785), hauer (1867), kišpatić (1892), kerner (1916) and other authors. barić (1957 and 1969) described in detail igneous rocks from the surroundings of sinj, vrlika, petrovo polje and knin, stating that they were albitized diabases. several samples of igneous rocks from the area of sinj and vrlika, which were investigated within the framework of this theme, are of the same composition and structure. they are hypabyssal coarse-grained rocks, belonging to altered albitized diabases. effusive eruptive rocks from the area of the una valley have not been precisely determined because of weathering, but they probably belong to the same type of igneous rocks which we find within the evaporitic complex of dalmatia. 5. geological relations of ev apo rites and associated deposits the described permain dep(>sits, although represented by different lithological members, make up a unique entity which is mainly structurally and tectonically separate from the mesozoic and paleogene deposits, while neogene sediments lie on them with a prominent angular and erosional discordance. however, primary contacts are mainly deranged by faults and particularly by diapiric movements of evaporitic complex of deposits. it is difficult to determine in the field where primary contacts are preserved and where they are deranged by diapirism. there are probably promina deposits in places that transgressively overlie the upper perm ian deposits. this is demonstrated by the similarity of the ground morphology with extension of the border between the promina sedi ments and upper permian deposits in the area of badanj, umljanović and markovac, and particularly the composition of basal promina conglomerates east of the krasići hamlet at drniš geologia croatica 45 (sakać, 1970). at this locality numerous pebbles of upper permian sandstone can be seen in the composition of the promina conglomerate, apart from other conglomerates. of course, these contacts today are deranged by faults or diapiric movements. the superpositional sequence and relation of the lithological members is not everywhere completely clear. field observation of the geological relations is particularly hindered by a large quaternary cover. however, in the area of middle dalmatia and in the border line arca of lika and bosnia, it can be clearly seen that evaporites are the oldest, and that clastics and carbonate sediments lie on them. clastics lie directly on evaporites, which was discovered in numerous exposed profiles (veliki and mali kukor, suhač, ćulumak and elsewhere in kosovo polje) and confirmed by drilling. moreover, in the area of kosovo polje, west of the mirković i hamlet (fig. 4) and petrovo polje on kadina glavica, and particularly at the first locality, multiple alternations of pelites and gypsum are clearly visible in thickness of several metres. however, dee per within the evaporites, intercalations of clastics have not been found anywhere. this indicates that clastics are in a normal sequence on evaporites, and rarely are found in the final phase of sedimentation of evaporites and sinsedimentary. the relation of carbonate facies dolomites and limestones is similar, while the problem of carbonate porous breccias is particularly more complex. in the area of sinj near the houses of labrović and dolić on outcrop in the top part of the gypsum deposits intercalations of gypsum with ash-grey dolomites are in alternation. here it is quite clear that we are dealing with sinsedimentional alternations of evaporites and dolomites. this is followed, in not quite clear relations, by a thick formation of dark­ grey and black stratified limestones and dolomites with intercalations of breccias. intercalations of sinsedimenta­ tional dolomite in gypsum were determined in the drill­ holes at stipanovića greben, as well as in the vicinity of sinj, mali kukor at kosovo polje, and some other places.however, in numerous open quarries and drill­ holes it has been determined that significant occurrences of carbonate are not found in evaporites, except in the top parts of an evaporitic sequence where they appear as intercalations and thinner layers. laminae, and more rarely thin layers, are present every where in evaporites. thus, evaporites are covered by tens of meters thick clastic, and considerably more rarely, carbonate deposits. therefore it follows that carbonate and clastic deposits lie directly on evaporites, and it can be concluded that carbonates and clastics were sedimented at the same time but in different conditions. the clastics themselves are frequently calcareous and in places contain intercalations of limestones (suhač, vrlika, etc.). unfortunately, in the field, there was no evidence of direct contacts of carbonate deposits and clastics where their mutual relations could be studied in more detail. only in the area of vrlika, outcrops of black, laminary micritic limestones are observed within the clastic rocks. sušnjara, sakač, jelen & gabrić : upper perrnian evaporites ... fi g. 4. schematic representation of the gypsum-shalc alternation near the mirković village in kosovo polje. slika 4. skica imljene gipsa i šejla kod zasooka mirković u kosovu polju. explanation of symbols: legenda: l. porous carbonate breccia supljikave karbonatne breče 2. gypsurn gips 3. shale sejl however, direct contacts are covered which means that their mutual relations arc not clear, even in this locality, allhough the general impression is that limestones lie underneath the clastics. grey to dark-grey porous carbonate breccias, in literature known as "rauhwacke" are represented in the carbonate facies. they are always conected to areas with evaporites. they are often directly on gypsum. in places they are connected to the upper permian dolomites and limestones, which can be seen in the area of u m ljanović and in the vrba valley where two smaller hills are built from porous carbonate breccias. it can bc seen that after exploatation of the surface portions for the needs of the construction industry, these breccias, towards the deeper parts, gradually pass into stratified, tectonic-broken dark­ -grey limestones. apart from larger or smaller disjected blocks porous brcccias can often be found on the gypsum. in the area of kosovo and petrovo polje, and sinj considerable masses of carbonate porous breccias exist. their relation with other lithological members of the evaporitic complex is not entirely clear, although much attention has been given to this problem. namely, direct contacts with other lithological members are regularly covered by quatemary sedi ments. at a number of places on kosovo polje large masses of carbonate breccias can be found, and in the immediate vicinity also thick deposits of clastic rocks. 103 ivanović et al. (1971) state that the porous carbonate breccias near orlić (kosovo polje) are located between red clastics and lower triassic deposits, and conclude that they most probably belong to the upper permian lower triassic transition, and "they could be coastal material formed in the upper perm ian along the borderline of emergent surfaces and the evapori tic basin, in a zone of alternative flooding and drainage". however, with a detailed examination of milića glavica near orlić, where the lower triassic deposits lie directly on the upper permian, we did not discover any occurrences of porous breccias, but well stratified limestones and dolomites,lying in unclear relations on the perm ian sandstones, while the clastics of the lower triassic lie over them. in the area of veliki kukor, kulen vakuf, and some other localitics, porous breccias lie over the clastics, but as bigger or smaller , mostly disconnccted blocks and fragments in clayey material, which indicates their secondary position, i.c. rcscdimcntation in the quaternary. at kosovo polje, in places at the foothills built of breccias, prirnary outcrops of upper permian clastic rocks are found, which indicate the possibility that these breccias at least lie partly on clastic rocks. however, their relation may bc the outcome of tectonic events and erosional proces ses. at petrovo polje near st. petka's church, neogene deposits lie on the blocks of dark-grey porous breccias, with the upper permian clastics lying undemeath breccias. in the vrba valley and at several local i ties in petrovo polje on the black porous breccias, lie loose or poorly cem en ted blocks and detritus of cretaceous limestones (rarely dolomites), and promina deposits (limestones and conglomerates). on the western side of kadina glavica, near meštrović' s mausoleum, neogene sedim en ts are found on such deposits. in the investigated arca the base of the evaporite deposits had not been yet discovered and therefore the thickness of these beds remains unknown. igneous rocks, mostly albitised and sericitised diabascs, exist in many places within the evaporitic complex of deposits in the entire investigated area. they are always small bodies, often morphologically prominent and of a conical shape. eruptive rocks are mainly connected to clastics and evaporites. unfortunately, direct contacts are regularly non-exposed. 6. age of ev apo rites and associated rocks a lot has been written on the age of evaporites and associated rocks. as these deposits are mainly dcvoid of fossils and are found in complicated structural-tectonic relations, conclusion on the age most frequently was brought on the basis of structural complex and direct contact with geological formations (the age of which had already been proved), and lithological similarity with known deposits. this can explain a variety of opinions about the age of these deposits. 104 this investigation focused particular attention on the solution of the question of the age of evaporites and associated deposits in the area of middle dal matia and borderline areas of lika and bosnia. besides observations in the field, paleontological, geochemical and petrological methods were applied. the results obtained are in agreement and all indicate the upper permian age. the geological framework of the evaporitic complex of deposits is made up of various members of mesozoic and cenozoic, but contacts are always of a fault-type and are of no great significance for the determination of the age of evaporites. in some rare cases, however, prim ary relations with the lower triassic deposits are preserved, which is very significant. at pa tiera glavica at petrovo polje kerner (1901) mentions findings of the lower triassic deposits with fossils anodontophora fassaensis wissmann, pseudomonotis cf. austriae bitiner, claraia clarai emmerich and other forms. these lower triassic deposits are located within the complex of evaporites and associated deposits, and undoubtedly overlie them, although mutual relation is not visible, being covered by alluvial deposits. similar relations exist at severallocalities in kosovo polje. at milića glavica lower triassic deposits directly overlie clastic rocks from the evaporitic complex of deposits. at patiera glavica, as well as at milića glavica, besides the lower triassic clastics, grey, stratified, late diagenetic dolomites and recrystallised limestones are found. similar carbonate deposits are located in the village ofpotkonje in the vicinity of the houses požar between .he seiser deposits and evaporites, and also in a base of lower triassic at muć. iv anović et al. (1971) state that at ćulum, close to the village of orlić, there is a location of seiser micaceous sandstones with steinkerns and moulds of pseudomonotis which directly overlie the clastics from the evaporitic complex of deposits. also, at kosovo polje, near the houses of ćenići and žmiko, sakać et al. (1970) determined a micro-fossil association belonging to the lower triassic,located in clastic deposits within the evaporitic complex. the significance of the mentioned local i ties is that the lower triassic deposits lie directly on clastics of an evaporitic complex, which surround them from all sides. this, also, indicates the upper perm ian age of evaporites and associated layers. in the western marginal area of kosovo polje at the konj and potkonj localities lower triassic deposits are present, probably directly overlying the evaporitic complex of deposits, though direct contacts are not visible -covered by quaternary deposits. nowhere else in the whole area of middle dalmati~ were mesozoic and paleogene deposits discolr'ered within the evaporitic complex. they form a tectonic framework in the marginal area of evaporites and associated deposits and have no great significance for the age of the evaporitic complex of deposits. in lika in the area of gornja suvaja, on the stretch from the hamlet of jovanović through đukić and as far geologia croatica 45 as skadar, the seiser clastic rocks in places directly overlie clastic rocks of the evaporitic complex of deposits. on this terrain also, direct contacts are almost invisible, being covered by secondary weathered materials. thus, considering the structural composition it follows that the clastics of evaporitic complex are older than se iser deposits. only in the una valley at kulen vakuf (rajinovci, krepala glava and buk) within the evaporitic complex of sediments, small occurrences of carbonate deposits now classed as j urassic (without paleontological proof of their age) are found but with clear tectonic contacts. in the area of middle dalmatia and the borderline areas of lika and bosnia, numerous well exposed continuous profiles are present through the whole mesozoic. but, nowhere in these deposits are there moulds of evaporites and associated deposits. in these areas "lemeš deposits" are present in the malm with dominant silicious sediments. in the conditions of such sedimentation in that sea a high sulphate concentration in the evaporite sedimentation could not be recognized. the petrographic characteristics of clastic rocks (types of sandstones·, and especially the composition and characteristics of heavy minerals) indicate a connection with the highest part of"groden facies" of a wider area in the dinarides (iv anović et al., 1971). also, on the basis of the petrographic characteristics of heavy minerals in the vrličko polje occurrences ofs clastics of transitional type with the upper perm ian and lower triassic mixed characteristics were found. isotopic analyses of sulphur in the samples of gypsum and anhydrite from the outcrops and quarries from dalmatia,'lika and the border area of western bosnia have standardized values which vary from 9.07 to 13.66 with a mean value of 11.12. sift ar (1986) reported almost identical results of isotopic analyses of evaporites from the una valley and middle dalmatia. mean isotopic value from 17 analyses is 10.7. according to siffar (1986), dolenc and pezdić (quotations from the study report) it can be concluded on the basis of the isotopic composition that the evaporite deposits from the forementioned areas are of upper perm ian age. numerous remains of fossil plants have been found in the clastics but unfortunately they have not yet been determined. rare and poorly preserved remains of macro­ fossils found in the clastic and carbonate rocks have also not been determined. a few samples of limestone were analysed for conodonts, but no positive results were obtained. however, in the primary clastics (grecnish­ grey and dark-grey pelites) directly overlying gypsum at suhač near sinj a very rich palynological material was found. tile association of corisaccites alutas, potonieisporites sp., lueckisporites virkkiae,klausipollenites schaubergeri, j ugasporiles delasaucei, lunalisporites sp. div., n uskoisporites dulhuntyi, perisaccus granulat us, gardenasporites heisseli, gigantosporites aletoides, strotersporites sp., according to brugman (1983), determines the lower part of the šušnjara, sakač, jelen & gabrić : upper permian evaporites ... upper perm ian (in the tri parti te division of the perm ian). in the sample from the locality near vrlika palynomorphs are badly preserved. the forms determined as cf. lueckisporites and cf. gigantosporites indicate the upper perm ian. a sample of gypswn from velili kukor (kosovo polje) contained very rare pieces of undefmable dissacate pollen. palynological anal>'ses were carried out on samples of clastics from the area in the una valley. a sample from the ćulumak locality near kulen v ak uf contains very rare dissacate coniferous pollen which, due to its poor condition, could not be determined. from the locality osredci­ novakovići in the wider area of srb the following forms were determined from samples of siltose pelites: luecldsporites virkkiae norm aa, luecldsporites virkkiae norm ab (dominant), lueckisporites virkkiae norm ac, klausipollenites schaubergeri, j ugasporites delasaucei, lunatisporites sp. div., nuskoisporites dulhuntyi, strotersporites sp., which stratigraphically defme the upper perm ian. according to brugman (1983), the dominance of the ab norm within the lueckisporites virkkiae phase characterizes the su bp hase 4. according to the same au thor the subphase 4 probably corresponds to the lower part of the dzulfian stage. these palynological determinations are generally the first paleontological evidence of the upper permian in evapori tes and associated deposits at the investigated area, and undoubtedly reference can be made to the upper permian age of the clastics directly over lying the evaporites. the same stratigraphical position is present for limestones and dolomites. evaporites, gypswn and anhydrite also belong to the upper perm ian with the possibility that the beginning of the evaporitic cycle might have belonged to the middle perm ian. taking into consideration all the above facts, as well as the genesis of evaporites and associated deposits, it can generally be said for the investigated areas that the beginning of evaporite sedimentation is definitely connected with the upper perm ian, and possibly the top part of the middle permian. the associated carbonate and clastic deposits belong to the upper permian, and that they at least in a part of the terrain probably continually spread into the lower triassic. dark-grey and grey carbonate porous breccias ("rauhwacke'') are set aside without indication of age. with regard to the possible genesis of these breccias, where their origin is connected with the land conditions of weathering in tectonised evaporitic-carbonate sedi ments of the upper perm ian, the existence of several generations of these breccias can be presumed. they could have been formed in the emersion of the upper permian following the sedimentation of the evaporites. it is possible that the majority of breccias were formed later in the process of tecto-genesis when evaporitic deposits broke out on to the surface. the possibility of theresedimentation ofbreccias, especially in thequaternary, shotjld be taken into consideration. with the in-the-field 105 examinations the breccias of the upper permian, pre­ neogene and quaternary age were defmed with cortairty, while all others remain in the field of asswnption. the age of the igneous roclcs presents a special problem. kerner (1916) states that the diabases occur in the form of veins which partly penetrate the "rauhwacke", lying in the bed of the triassic, and partly even the lower verfenian schists. one vein of the diabase porphyry also penetrates the upper verfenian layers. on the basis of these data the eruptives can be ascribed to the middle triassic. this opinion on the middle triassic age of the igneous roclcs from the surroundings of sinj, was later accepted by all explorers for all occurrences of eruptives in the area of middle dalmatia; iv anović et al. for the first time (1978) when referring to the igneous roclcs from kosovo polje, petrovo polje and near vrlika, state that the permo-triassic clastics, occurring with volcanites, contain volcanic rock fragments and identical heavy minerals, which means that diabases had existed before the clastics were formed. furthermore, widespread occurrences of the secondary growth of quartz in clastics, together with authigenic quartz crystals and authigenic tourmaline, point to the active effect of volcanism. accordingly, it can be assumed that volcanites are of the same age or somewhat older than the penno-triassic clastics. pamić (1982) explains albitised diabases from the area of middle dalmatia, including a wider area of ou ther dinari des (v an jski dinaridi), by triassic volcanism. raić et al. (1984) in an explanation for the sin j newspaper allows the possibility that the spilitised diabases from the sinj area may even be of neogene age. these investigations determined that the albilised diabases are connected with the upper perm ian complex of sediments. fragments and pebbles of albitised diabases are found in evaporites, clastics and porous breccias. in the surroundings, and even in wider areas, within the lower triassic deposits of wide distribution, no occurrences of igneous rocks have been discovered. in the middle dal matia and in the borderline area of bosnia (on the southern slopes of svilaja, north of knin, near bosansko grabovo, and others) the occurrences of igneous rocks connected to the middle triassic volcanism, are present. however, these are effusive rocks, basalts, associated with tuffs, connected with submarine effusions (šćavnićar et al., 1984), while hypabyssal rocks are present in the permian deposits. as we are dealing with the veinal rocks, without detailed research, it is not recommended that conclusions are made on their age. qui te rare findings of fragments, and even pebbles, of these eruptives in evaporites and clastics, as well as a lack of igneous rocks in the lower triassic deposits, suggest the upper permian age. 7. a review of the ev apo rites of western and southwestern bosnia and herzegovina an examination of the occurrence of evaporites and associated deposits in the area of western and south106 western bosnia and herzegovina (fig. 5) revealed significant factors which indicate their stratigraphic and tectonic position and also the similarity in development and occurrence with the evaporitic complex of deposits in the investigated areas ofdalmatia and the una valley. the evaporites occur along significant tectonic dislocations. the majority of sites are linked with perm ian or lower triassic deposits. on severallocalities in the immediate roof pend an t of evaporites there are peli tic-carbonate deposits in which fossil remains were not found, and thus on the basis of the superposition in the sheets of the basic geological maps, scale l: l oo 000 were classified in the permo-triassic. these sediments normally pass into deposits in which the lower triassic age was established, so they could belong to the upper permian. on some locatilities evaporites were linked with the red, typically upper perm ian clastics. but, it was not entirely clear whether these clastics were underlying evaporites or whether the evaporites were intercalated in the clastics. in this flg. s slik• • geologia croatica 45 area, as in the investigated areas in dalmatia and in the border areas of lika and bosnia, porous carbonate rocks, the so-called "rauhwacke" are frequently found on the evaporites, and are often broken into larger or smaller blocks. interestingly enough, on the sites around the ljubinačka river, the "rauhwackes" are found as "lens­ like" bodies concordantly intercalated in the upper­ permian red clastics, and are not in direct contact with evaporitcs. it can be concluded that evaporites in the arca of western and south-western bosnia and herzegovina are also of the upper perm ian age. this was pro v ed by the results of the isotopic analyses of sulphur from gypsum and anhydrite performed by j. pezdić, and the petrographic analyscs of j. tišuar and al. šimunić. the petrological characteristics of evaporites are very similar to or identical with the evaporites from the area of dalmatia and the una valley. gypsum is present on the surface, and anhydrite in deepcr parts of the terrain. intercalations and laminae of dolomicrytes are present localities of investigated evaporite outcrops on the territory of bosnia and hercegovina lokacue pregledanih nalazista evaporita na podrućju bosne l hercegovine 1. iovtci j . luo l linj , l juiiiiiiačic a lli.jli(a 4. yaoan.iac l ... tiiica l . koi'iiivhica 1. ilf~ovac l. vol. alil l dočići l . i'livika jfziiia 10. hoćunf if, ai(oha 1l , kotaiilvac 12, i'itkovac 14. ofiivis kula is. .a kolac · doiiienica o 10 100 km šušnjara, sakač, jelen & gabrić : upper permian evaporites ... in the evaporites. 8. conclusion the investigated evaporites and associated deposits consist of gypsum and anhydrites on which, in a normal sequence, carbonate and clastic deposits are found. carbonate rocks are represented by dolomites, limestones and carbonate porous breccias ("rauhwacke") and clastics are represented by pelites, siltstones and sandstones, and very rarely by conglomerates. apart from these sediments frequently there are small occurrences of altered albitised diabases. in the gypsum and anhydrite intercalations and laminae of dolomicrytes and scattered grains of carbonates are regularly present, while sinsedimentary occurrences of clastics in evaporites are very rare. gypsum was formed by hydratisation of anhydrites in the surface conditions. these deposits, although facially different, make up a unique complex which is structurally and tectonically separate from mesozoic and older paleogene deposits, while the neogene and somewhere upper eocene ("promina deposits") sediments overlie them in transgressive contact, which was lately disturbed by tectonics and diapirism. the evaporitic complex of deposits has been attributed to various ages, from the upper-permian to cretaceous, although without paleontological documentation. with these investigations on the basis of palynological analyses the upper permian age of these deposits was determined. in agreement with this are the occasionally preserved superpositional relations with lower triassic (seiser level), the petrographic investigation, and the isotopic analysis of sulphur from the evaporites. for the carbonate porous breccias ("rauhwacke") it was determined that there are several generations; permian, pre-neogene and quaternary, which is in agreement with their genesis and position on the site. acknowledgement it is our pleasure to acknowledge various forms of assistence of numerous professional and scientific collaborators from different fields of geology for their valuable contribution and the results of the former and the present investigation, especially to dr. b. šćavni­ ćar. we extand our thanks to the company "ina­ naftaplin-geological survey" which sponsored this investigation and to ing. r. tonćić-gregl who was a coordinator of this pro ject and ing. ž. krušlin who was in charge of financial matters. we would like to thank to a. jurić for his graphical work and to j . banović for typing. 9. references barun, s.(1985): trijaske naslage i jelar formacija u dolini une između srba i brotnje. geol. vjesnik, 38, 21-30, zagreb. barić, u. (1957): eruptivi iz okolice sinja u dalmaciji uz kraći osvrt na eruptivne pojave kod knina, vrlike 107 i drniša.ii kongr. geol.jugosl., 255-262. sarajevo. barić, u. (1969): eruptivgesteine (albitisierte diabase) in der umgebung von sinj,dalmatien. geol. vjesnik, 22 (1968), 349-410, zagreb. blašković, i. (1983): underthrsting model of genesis and position of the carbonate-evaporitic complex in the north-eastern part of the adriatic sea. intern. assoc. sediment., abstracts, 4th regional meeting, 22-24, split. boško v-štajner, z . (1971 ): prilog strati grafiji jadran­ skog oboda.nafta, 22/4-5,270-274, zagreb. brugman, w. a. (1983) : permiantriassic palynology. -laboratory of palaeobotany and palynology, s tate university utrecht, 1-121, utrecht. chorowicz, j. (1975): le mecanisme de la structure transversale split-karlovac, dans les dinarides yougoslaves.-c. r. acad. sc., (d), 280, 23132316,paris. chorowicz, j. (1977): etude geologique des dinari des le long de la structure transversale split-karlovac (yougoslavie).-societe geol. du nord, l, 1-330, villeneuve. ćanović, m. (1969): stratigrafski položaj evaporitske formacije u istražnim bušotinama na naftu u crnoj gori.-vesnik zavoda za geol. i geofiz. istraž., 27(a),l47-157, beograd. ćićić, s. (1987): ležišta gipsa i anhidrida u jugoslaviji. geol. glasnik, 31-32, 173-185, sarajevo. đurasek, n., frank, g., jeni< o, k., kužina, a. & tonćić-gregl, r. (1981): contribution of the understanding of oil-geological relations in nw adriatic area. proceed. i symp. scient. conseil for oil. jugosl. akad. znan. umjetn. (a), 8, 201213, zagreb. foetterle, f. (1862): geologische karte der licca. jahrb. geol. reichsanst., 12/4, (verh. p. 298), wien. for tis, a. (1774): viaggo in dalmazia.pressa al vise miloeco. vol. i, viii +180+47, vol. ii, (4) + 204, venezia. franić, d. (1900): zemljopisne sitnice. (sadra i sumpor na kukinoj glavici u srbu i dr.). glasnik hrv. nar. društva 12/1-3, 169-171, zagreb. grimani, 1., juriša, m., šikić , k. & šimunić, an. (1975) : tumač osnovne geološke karte sfrj, l: 100 000, list knin, (l-33-141), 1-61.inst. geol. istraž. zagreb, savez. geol. zavod beograd. grimani, 1., šikić, k & šimunić, an. (1972): osnovna geološka karta sfrj, l: 100 000, list knin, (l 33141).-inst. geol. istraž. zagreb, savez. geol. zavod, beograd. hacquet, b. (1785): physikalisch-politische reise auf dinarischen durch die julischen, camischen, r~tischen in die norischen alpen, im jahre 1781 und 1783 untemommen.bd. i, ii, leipzig. hauer, f. (1867): prehnit von comisa auf der insel lissa und eruptivgesteine aus dalmatien. -vehr. geol. reichanst., 4, 89-91, wien. 108 hauer, f. (1868) : geologische obersichtskarte der osterreichischen monarchie nach den aufnahmen del' k.k. geol reichsanstalt. blatt nr. 10. dalmatien. jahrb.geol. reichsanst, 18/3,431-454, wien. herak. m. (1973): some tectonical problems of the evaporitic area in the dinari des of croatia. g eo l. vjesnik, 26, 29-40, zagreb. herak, m. (1983) : some ideas and dilemmas cohcerning the genesis and tectonic of adriatic and periadriatic areas.in: babić, u. & jelaska, v. (eds.): contributions to sedimentology of some carbonate and clastic units of the coastal dinarides. intern. assoc. sedim., excurs. guide book. 41h regional meeting, 7-11, split ivanović, a., sikirica, v., marković, s. & sakać, k. (1977): osnovna geološka karta sfrj, l : 100 ooo,list drniš, (k 33-9). inst. geol. istraž. zagreb, savez. geol. zavod, beograd. ivanović, a., sikirica, v. & sakać, k. (1978): tumač osnovne geološke karte sfrj, l : 100 000, list drniš, (k 33-9). -inst geol. istraž. zagreb, savez. geol. zavod, beograd. iv anović, a, šća vnićar, b., sakać, k. & gušić, i. (1971) : stratigrafski položaj i petrografske karakteristike evaporita i klastita okolice drniša i vrlike u dalmaciji. geol. vjesnik, 24, 11-33, zagreb. ka tzer, f. ( 1903) : gelogischer fiihrer durch bosni en und die hercegovina. -ix internat geologencongr. landesreigerung in sarajevo, 1-280, sarajevo. katzer, f. (1921) : pregledna geološka karta bosne i hercegovine, l :200 000, banja luka geol. zavod sarajevo. ka tzer, f. (1925) : geologie bosni es und der herzego­ vina. geol. zavod sarajevo, 1-480 (i h.), 481560 (ii h.), sarajevo. kerner, f. (1901) : erllluterngen zur geologischen karte der im reichsrathe vertretenen konigreiche und uinder der osterr.ungar. monarchie. sw gruppe nr. 121, kistanje-drniš. (zone 30, col. xiv der specialkarte der osterr. ungar. monarchie im geologia croatica 45 mabstabe l : 75 000). geol. reichanst., 1-40, wien. kerner, f. (1916) : erlllterungen zur geologischen karte der im reichsrate vertretenen konigreiche und uinder der osterr.-ungar. monarchie. sw gruppe nr. 124, sinj und spalato. (zone 31 , col. xv der spezial-karte der osterr.-ungar. monarchie im mabstabe 1:75 000).-geol. reichsanst, 1-116. wien. kerner, f. (1920). erllluterungen zum nachtrag zur geologischen karte der im reichsrathe vertretenen konigreiche und uindere der osterr.-ungar. monarchie. sw gruppe nr. 119, knin und ervenik (zone 29, col. xiv der spezialkarte dervormaligen osterr.ungar. monarchie im mabstabe 1:75 000). -geol. reichanst., 1-32, wien. • kišpatić, m. (1892): eruptivna kamenje u dalmaciji. -rad jugosl. akad. znan. umjeto., ll l (matem.­ prir. razr., 15), 158-190, zagreb kišpatić, m. (1901): rude u hrvatskoj. rad jugosl. akad. znan. umjeto. 147 (matem.-prir. razr., 30), 1-104, zagreb. klaus, w. (1963): sporen aus dem siidalpinen perm. jahrb. geol. bundesanst. (aust.), 106, 229-363, wien. koch, f. (1914a) : geologijska prijegledna karta kralje­ vine hrvatske i slavonije. tumač geologijske karte gračacermain (zona 28, col. xiv).naklada kralj. hrv.-slavon.-dalm. zemalj. vlade, odjel za bogoštovlje i nastavu, 8, 1-42, zagreb. koch,f. (1914b): geologijska prijegledna karta kraljevine hrvatske i slavonije l :75 000 gračac-ermain (zona 28, col. xiv). izd. kralj. hrv. slav. dalm. vlade, odio unutar. poslova zagreb. kranjec, v. (1979) : o naftoplinosnosti karbonatno­ evaporitnih naslaga u circum-mediteranskim i nekim drugim zemljama i jadranskom primorju. nafta, 30/3,103-124, zagreb. mojsisovics,e., tietze, e. & bittner, a. (1880): grundlinen der geologie von bosnien und herzegovina. -jahrb. geol. reichsanst, 30(2, 159462, wien. pamić, j. (1982) : trijaski magmatizam dinaridaposeb. plate tabla i. enlargements 1000 x, fig.4 750 x. l. spore indet. site osredci novakovići. 2. spore indet. site osredci novakovići. 3. potonieisporites sp. site suhač. 4. nuskoisporites dulhuntyi potonil~ & klaus, 1954. site osredci novakovići. 5. perisaccus granu/atus klaus, 1963. site suhač. 6. falcisporites 7apfei (potonje & klaus, 1954) leschik, 1956. site suhač. 7. klausipol/enites schaubergeri (potonffi & klaus, 1954) jansonius,l962. site osredci n ovakov ići. 8. vesicaspora scheme/i klaus, 1963. site osredcincvakovići. 9. paravesicaspora splendens klaus, 1963. site osredcinovakovići. 10. platisaccus papilionis potonje & klaus, 1959. site suhač. ll. illinites pemphicus klaus, 1963. site suhač. šujnjara, sakač, jelen & gabrić : upper permian evaporites ... platetabla i 109 \. _ .. 1 2 3 ' • 4 5 6 7 8 9 10 11 110 izd. nafta, 1-236, zagreb. papeš, j., magaš, n., marinković, r., sikirica, v. & raić, v. (1982): osnovna geološka karta sfrj,!: 100 ooo,list sinj (k 33-10).-geoinženjering, institut za geologiju sarajevo, geološki zavod, oour za geologiju i paleontologiju zagreb, savez. geol. zavod, beograd. podubsky, v. (1963): regionalne karakteristike geneze i geotektonskog položaja gips-anhidridskih ležišta zapadne bosne i hercegovine i hrvatske.geol. glasnik, 7, 161-167, sarajevo. podubsky, v. (1976): gips i anhidrid. -mineralne sirovine bosne i hercegovine. prvi tom, kn j. illežišla nemetala, 328-338, geoinženjering, sarajevo. raić,v.,papeš.j., sikirica, v.& magaš,n.(1984): tumač osnovne geološke karte sfrj, l : l oo ooo,list sinj (k 33-10).geoinženjering,lnstitut za geologiju sarajevo, geološki zavod, oour za geologiju i paleontologi ju. izd. savez. geol. zavod, l-52, beograd. sakać, k, gušić, i. & šća vnićar, b. (1970): age of the clastic and evaporite deposits in environs of drniš (dalmatia).bull. sci. cons. acad. yougosl.(a),l5/910, 312-313, zagreb. sakać,k (1970): analizaeocenskog{idecreljefai tclctooskih zbivanja u području drniša u dalrnaciji.-geol. vjesnik, 23, 163-179, zagreb. schubert, r. (1920): geologische spezialkarte der im reichsrate vertretenen kooigreiche und uinder der ostmeichische-ungar monarchie, l :75 000, knin und ervenik (zone29 col. xiv).geol. reichsanst, wien. skeru, j. (1974): ležišta gipsa slane stine kod sinja. geologija, 17, 415-422. ljubljana. staciffi, g. (1899): dieliburnischestufeund deren grenz­ horizonte.-abh. geol. reichsanst,13, 1-170. wien. šća vnićar, b. (1973): kalupi kristala kamene soli (hali ta) u klastitima na području vrlike i knina. geol. vjesnik,26, 155-157, zagreb. šća vnićar, b.,šća vnićar,s. & šušnjara, a (1984): vulkanogeno-sedimentni srednji trijas u području geologia croatica 45 potoka suvaje (svilaja pl. vanjski dinaridi).acta geologica, 14/2, 35-82, zagreb. šća vnićar, b. & šušnjara, a (1983): the geologic column of the lower triassic at muć (southern croatia).acta geologica, 13/1, 1-25, zagreb. šiff ar, d. (1982) :izotopni sastav sumpora i starost evaporita s primjerima iz područja dinarida u južnoj hrvatskoj.nafta, 33/4, 177-183, zagreb. šiftar, d. (1986): starostevaporita u području sinjgornji tok une. geol. vjesnik, 39, 55-60, zagreb. šuklje,f. (1914): naslage sadre kod srba u lici. priroda, 3-4, 87-88, zagreb. šušnjar, m (1981 ): genetski faktori i geološke okolnosti mobiliteta i dijapirizma s osvrtom na mobilna i mobilna stanja kalcijsko-sulfatnih naslaga uprostoru dinarida.nafta, 1-221, zagreb. šušnjar, m (1983): tektogenetski procesi u dina-ridima ipojave pozitivnih geotermalnih anomalija.geol. vjesnik, 36, 223-239, zagreb. šušnjar,m&bukovac,j.(1978): osnovna geološka karta sfrj, l : 100 000, list drvar, (l 33-129). -institut za geol. istraž. zagreb,savez. geol. zavod. beograd. š uš njar, m. & bukov ac, j. (1979): tumač osnovne geološke karte sfrj, l : 100 ooo,list drvar, (l33129), 1-44.institut za geol. istraž. zagreb, savez. geol. zavod, beograd. šušnjar, m., bukov ac, j., marinćić, s. & savić, d. (1965): stratigrafija gipsanih naslaga unske doline i korelacija s poznatim evaporitnim naslagama i popratnim facijesima u primorju, dalmaciji, lici i zapadnoj bosni. acta geologica, 5, 407-422, zagreb. šušnjara, a. (1974): permoskitski peliti kao sirovina za ekspandirani laki agregat i ciglarske proizvode. -geol. vjesnik, 27, 363365, zagreb. visscher, h. (1971 ): the permian and triassic of the kingscourt outlier, ireland.geol. surv. ireland, spec. pap. 1-114, dublin. plate tabla ii. enlargements 1000 x, fig. 5 750 x, fig. 9 660 x. l. illinites sp. site suhač. 2. jugasporites de/asaucei (potonu~ & klaus, 1954) leschik, 1956. site osredcinovakovići. 3. jugasporites perspicuus leschik, 1956. site osredci novakovići. 4. limitisporites moersensis (grebe, 1957), klaus, 1963. site suhač. 5. limitisporites sp. site suhač. 6. gardenasporites heisseli klaus, 1963. site suhač. 7. gardenasporites moroderi klaus, 1963. site suhač. 8. gardenasporites leonardii klaus, 1963. site suhač. 9. gigantosporites aletoides klaus, 1963. site suhač. 10. corisaccites alutas venkatachala & kar, 1956. site suhač. ll. lueckisporites virkkiae potonie & klaus, 1954 (norm aa visscher,i971). site suhač. šufnjara, sakač, jelen & gabrić : upper perm ian evaporites ... •• 1 4 9 ..... ' ... 2 ',":. ~ ~ , ... · .. 'ft-...... tt . 7 ...... . . ·.,-ll.·,.; l. ~-l ·/ ... .,,., t • . . . .. 5 ' platetabla ii 111 3 6 • 8 10 11 112 geologia croatica 45 gornjopermski evaporiti i prateće stijene dalmacije i graničnog područja like i bosne a. sušnjara, k. sakač, b. jelen i a. gabrić gomjopermski evaporiti i prateće naslage detaljno su istraživani u sjevernoj i srednjoj dalmaciji, te graničnom području like i bosne. sastoje se od evaporita, karbonatnih i klastičnih naslaga s kojima su povezane mnogobrojne manje pojave izmijenjenih albitiziranih dijabaza evaporiti su predstavljeni gipsom i anhidritom. karbonati su dolomiti, vapnenci i karbonatne šupljikave breče (tzv. "rauhwacke"). klastiti su peliti, siltiti i pješčenjaci, ili su vrlo rijetko konglomerati. evaporiti su uslo jeni i vrlo intenzivno boran i. boje su tamnosive do svjetlosive i bijele. redovito sadrže leće, proslojke i lam ine glinovite komponente, a prisutna je i organska supstancija s piritom. zbog izmjene sivih, svjetlosivih i bijelih proslojaka, gips je često trakaste teksture. s karakterističnom fibroznom strukturom kristalizirao je krupnozrnasto do sitnozrnasto. u površinskom dijelu (do dubine 20-40 m) nalazi se gips, a dublje postupno prelazi u anhidrit. u istraž ivanim terenima baza evaporita nije otkrivena. dolomiti se izmjenjuju s evaporitima ili se nalaze kao ulošci u vapnencima. boja im je pepeljasto siva do crna. pripadaju ranodijagenetskim kriptokristalastim dolomitima (dolomikritima). redovito sadrže organsku supstanciju, a ponekad i sitne kristaliće autigenog kvarca. vapnenci se također odlikuju dobrom uslojenošću . mjestimice su laminirani. boja im je siva, tamnosiva ili crna od primjesa bituminozne supstancije. često su ispresijecani brojnim bijelim kalcitnim žilicama. pripadaju mikritima. rijetko su zahvaćeni dolomitizacijom. mjestimice sadrže auti geni kvarc. u području sela glavice kod sinja i umljanovića kod drniša, u vapnencima se nalaze kristalići fluorita. karbonatne šupljikave breče "rauhwacke" vezane su uz evaporitni kompleks naslaga. karakteriziraju ih brojne male šupljine često ravnih ploha ili sustava nepravilno oblikovanih kanalića. ponekad izgledaju poput šljake. u sitnozmastoj kalcitnoj osnovi često spužvastog do saćastog rasporeda sličnog sedri, nalaze se fragmenti gomjopermskih vapnenaca i dolomita, a rijetko gornjopermskih klastita, gipsa i eruptivnih stijena. fragmenti su uglavnom angularni, rijetko i subzaobljeni. breče su nesortirane, masivne neuslojene. boje su smeđaste ili tamnosive. klastiti su pretežno crveni, a često se izmjenjuju sa sivim i zelenkastosivim, dok su znatno rjeđi smeđesivi i crni. najčešće su dobro uslojeni . u klastitima su dominantni peli ti. s povećanjem krupnoće zrna klastita opada njihovo učešće, tako da su konglomerati zabilježeni tek kao manje pojave na nekoliko lokaliteta. peliti uz osnovnu komponentu minerala glina; ilita, montmo­ rilonita, kaolinita i hidromuskovita, redovito sadrže još i kalcit, klorit, muskovit, feldspat i sitna zrna kvarca. kod petita često je izražena finolistićava cj epivost paralelne slojevitosti. peliti često pripadaju karbonatnim šejlovima. u siltitima, a naročito pješčt?njacima, opada sadržaj glinovite komponente, a raste učešće siltno-psamitnog terigenog detritusa: kvarca, feldspata, muskovita, k l ori ta i čestica stijena. pješčenjaci imaju visok sadržaj kvarca koji obično prelazi 75% od ukupno prisutno g detritusa. dominantan tip cementa je kemo geni kvarcni cement, dok je matriks detritičnog porijekla rjeđi. pješčenjac i su zastupljeni tipovima grauvaka (kvarcnih, feldspatskih i tinjčastih), subarkoza (kvarcnih i tinjčastih) , te kvarcarenita i kvarclitoarenita. eruptivne stijene, većinom izmjenjeni albitizirani dijabazi, nalaze se na niz mjesta u sklopu evaporitnog kompleksa naslaga. redovito su to mala tijela, često morfološki istaknutog i čunjastog oblika. razvoj evaporita i pratećih stijena vrlo je s ličan na plate tabla iii. enlargements 1000 x. l. lueckisporites virkkiae potonil~ & klaus, 1954 (norm ab visscher, 1971). site osredci ­ novakovići. 2. lueckisporites virkkiae potonu~ & klaus, 1954 (norm ac visscher, 1971). site osredci n ovakov ići. 3. lueckisporites virkkiae potonii~ & klaus, 1954. site suhač. 4. lueckisporites sp. l. site suhač . 5. lueckisporites sp. 2. site osredci novakovići . 6. lunatisporites ortisei (klaus, 1963) brugman, 1983 (unpubl.). site suhač. 7. lunatisporites a/atus (klaus, 1963) brugman, 1983 (unpubl.) site suhač. 8. striatites jacobii jansonius, 1962. site osredci novakovići. 9. striatites sp. site osredci novakovići. 10. ephedripites primus klaus, 1963. site suhač. ll. cycadopites sp. site suhač. šulnjara, sakač, jelen & gabrić : upper perm ian evaporites ... platetabla m 113 • 1 2 3 .~ 4 5 6 .. • .. 7 8 . =[ 9 10 11 114 čitavom istraživanom području. nalaze se uglavnom u nižim dijelovima terena, u krškim poljima i dubokim dolinama. povezani su s labilnim tektonskim zonama, kompliciranim strukturno-tektonskim odnosima i dijapirskim utiskivanjima. ove naslage, premda facijesno raznolike, jedinstvena su cjelina. strukturno i tektonski izdvojeni (lu od· mezozojskih i paleogenskih naslaga. neogenski ij.c4imenti izravno leže na evaporitnom kompleksu ::taslaga s izraženom kutnom i erozijskom diskordancijom. vjerojatno su i promina naslage bile primarno, barem mjestimice transgresivne na evaporitnom kompleksu, kao u petrovu polju i kosovu polju. na to upućuje odnos geoloških granica i morfologije terena. osim toga, u sastavu bazalnih konglomerata promina naslaga kod drniša, uz ostale, nalaze se i mnogobrojne valutice gornjopennskih pješčenjaka. međutim, primarni kontakti gornjopermskih naslaga s neogenskim sedimentima, a osobito s promina naslagama su poremećeni rasjedima i dijapirskim kretanjima evaporita i pratećih naslaga. superpozicijski slijed i međusobni odnosi litoloških članova evaporitnog kompleksa uglavnom je istovjetan na čitavom istraži vanom području. najstariji su evaporiti, a na njima neposredno leže karbonatni i klastični sedimenti koji su vjerojatno taloženi istodobno, ali u različitim uvjetima. mjestimice, u vršnom dijelu evaporitne serije, ima višestrukih izmjena evaporita s karbonatima, vrlo rijetko i s klastitima. sinsedimentacijski dolomikriti redovita su pojava u evaporitima. povezanost ldastita s evaporitima pokazuju i kalupi halita koji se u njima nalaze. odnos s karbonatnim šupljikavim brečama znatno je zam~niji. nalaze se u različitim položajima. najčešće šupljikave breče leže izravno na gipsu, ali i uz karbonatne stijene, pa i na klas~itima. o starosti evaporita i pratećih naslaga postojala su različita stanovišta. svrsta vani su u stratigrafske jedinice od permotrijasa do krede prevladavalo je mišljenje o permotrijaskoj i donjotrijaskoj starosti sedimenata, ali bez paleontoloških dokaza. našim istraživanjima taj je problem rješavan kompleksno s više metoda. dobiveni rezultati suglasni su i dokazuj~> gornjopermsku starost. petrografska obilježja klastita, tipovi pješčenjaka, a osobito sastav i karakteristike •.eških minerala iz klastita upućuju na vezu s najvišim nivoima "gredenskog" facijesa iz ostalih područja zapadnog dijela dinarida (iv anović et al., 1971). izotopne analize sumpora iz gipsa i anhidrita dale su ujednačene vrijednosti od 9,07 do 13,66, što također upućuje na gornjopermsku pripadnost. primarni odnosi evaporitnog kompleksa naslaga s donjotrijaskim sedimentima sajskog nivoa vrlo rijetko su očuvani u istraživanim terenima. tako na nekoliko mjesta u petrovu polju i kosovu polju na karbonatnim i klastičnim naslagama iz evaporitnog kompleksa izravno leže sa jski sedi menti. slični odnosi zapaženi sij u gornjoj suvaji nedaleko srba. međutim, najvrijednije dokaze za stratigrafsku pripadnost evaporitnog kompleksa naslaga !jokazale su palinološke analize kojima je prvi put precizno utvrđena geologia croatica 45 njihova starost. u klastitima, koji leže neposredno na evaporitima kod sinja, nađen je bogat i dobro očuvan palinološki materijal. asocijacija corisaccites alutas, potonieisporites sp., lueckisporites virkkiae, klausipollenites schaubergeri, jugasporites delasaucei, lur.atisporites sp. div., nuskoisporites du/huntyi, perisaccus granulatus, gardenasporites heisseli, gigantosporites aletoides, strotersporites sp., prema studiji br ug mana (1983) dokazan je donji dio gornjeg perma (u trodjelnoj podjeli perma). u klastitima iz šire okolice srba (osredci-novakovići) određena asocijacija lueckisporites virkkiae norm aa, lueckisporites virkkiae norm ab (dominanta), lueckisporites virkkiae norm ac, klausi{xj//enites schaubergeri,j ugas{xjrites delasaucei, lunatisporites sp. div. , nuskoisporites du/huntyi, strotersporites sp., isto potvrđuje gornji perm. prema studiji brugmana (1983) dominacija norm ab u okviru lueckgporites virkkiae faze karakterizira sub fazu 4 kojoj vjerojatno odgovara donji dio dzulfijskog kata. u klastitima vrličkog polja palinomorfe su loš ije očuvane, a· određene su kao forme cf. lueckisporites i cf. gigantosporites, što upućuje na gornji perm. prisutan j~ polcn i u kosovu polju te kod kulen vakufa, ali zbog loše očuvanosti nije ga bilo moguće odrediti. na osnovi iznesenih činjenica ntože sc reći za istraživano područje da je taloženje evaporita sigurno vezano za gornji perm, a moguće je da je započelo u gornjem dijelu srednjeg perma. prateće karbonatne i klastične naslage pripadaju gornjem permu, a moguće je da u dijelu područja kontinuirano prelaze u donji trijas. karbonatne šupljikave breče ("rauhwacke") najvjerojatnije su proizvodi fizičkog i kemijskog trošenja jako tektoniziranih icarbonatno-evaporitnih sedimenata. na:;tali su u kopnenim uvjetima. prema njihovoj genezi i na temelju utvrđenih položaja i odnosa s drugim stratigrafskim članovima, zaključuje se da postoji više generacija ovih breča. starost im može biti od gornjeg perma do kvartara. sigurno su utvrđene gornjopermske, prcdneogenske i kvartarne "rauhwacke". eruptivne stijene, albitizirani dijabazi, vezani uz evaporitni kompleks naslaga, također mogu pripadati gornjem permu. na to upućuju i nalazi fragmenata ovih stijena u gornjopermskim klastitima. na :>snovi tako utvrđenih či'ljenica <.' stratigrafskoj pripadnosti evaporitnog korr.pleksa naslaga bilo je moguće načiniti više značajnijih izmjena t: dosadašnjim interpretacijama geoloških odnosa prikazanih na· pojedinim listovima osnovne geološke karte sfrj l: l oo 000. ovo se osobito odnosi na širu okolicu srba i područje duž gornjeg toka rijeke une (sl. 3). pregledana su takođe• i brojna nalazišta e-..aporita u zapadnoj bosni i hercegovini. utvrđeno je da se oni nalaze u sličnim strukturnim odnosima i razvoju kao u napri_ierl o!'isanim područjima. zaključuje se da i oni također vjeroj~tno pripadaju gornjem permu. manuscript received march, 31.1992. revised manuscript accepted june, 10.1992. 01-mhasoub.indd mahsoub et al.: bioand sequence stratigraphy of upper cretaceous – palaeogene rocks, east bahariya concession, western desert, egypt 109 � ab stra ct this work deals with the plankton stratigraphy of the subsurface upper cretaceous-palaeogene succession of the east bahariya concession based on planktonic foraminifera and calcareous nannofossils. the examination of the cuttings from fi ve wells: aqsa-1x, karma-e-1x, karma-3x, karma-nw-1x and karma-nw-5x is biostratigraphically evaluated. it is possible to identify the planktonic foraminifera as well as the calcareous nannofossil biozones. the analyses of calcareous nannofossils revealed the presence of several hiatuses. information obtained from well data such as seismic facies analysis for the studied area has enabled classifi cation of the upper cretaceouspalaeogene succession into fi ve major 2nd order depositional sequences, separated by four major depositional sequence boundaries (sb1, sb2, sb3 and sb4). the upper cretaceous-palaeogene succession in the east bahariya is divided into 17 systems tracts. these systems tracts are: 7 system tracts of probable cenomanian age, (the sequence stratigraphic framework as well as the cycles and system tracts of the cenomanian bahariya formation match well with those of catuneanu et al., 2006); 4 system tracts of turonian age, 2 system tracts of campanian-maastrichtian age and 4 system tracts of eocene age. keywords: planktonic foraminifera, calcareous nannofossil, upper cretaceous, palaeogene, seismic interpretation, sequence stratigraphy, bahariya, egypt bioand sequence stratigraphy of upper cretaceous – palaeogene rocks, east bahariya concession, western desert, egypt � mohamed mahsoub1, radwan a.bul-nasr1, mohamed boukhary2, hamed abd el aal1 and mahmoud faris3 1 faculty of education, ain shams university, cairo, egypt; (mahsoub2005@hotmail.com; rabulnasr@ yahoo.com; mabdelaal81@yahoo.com) 2 department of geology faculty of science, ain shams university, cairo, egypt; (moboukhary@yahoo.com) 3 department of geology faculty of science, tanta university, tanta, egypt; (mhmfaris@yahoo.com) doi: 104154/gc.2012.09 geologia croatica 65/2 109–138 33 figs. 1 tab. zagreb 2012 geologia croaticageologia croatica 1. introduction the western desert of egypt covers an area of approximately 700, 000 km2, which represents two thirds of the total area of the country (egpc, 1992). the study area (fig. 1) covers the karama field in the east bahariya concession (ebc), located in the eastern margin of the abu gharadig basin. the karama field was discovered in january 2000 by repsol and apache, while drilling the karama 1-x well, which produced oil from the abu roash member. the abu gharadig basin is located in the central northern part of the western desert. topographically the abu gharadig basin can be subdivided into two main troughs, the western and eastern trough. this basin is recently considered to be the most promising of all as far as hydrocarbon potential is concerned since several oil and gas discoveries had been recorded within its thick marine cretaceous sequence (awad, 1984). the aim of the present work is the study of the planktonic foraminiferal and calcareous nannoplankton biostratiggeologia croatica 65/2geologia croatica 110 raphy of the upper cretaceous – palaeogene rock units in the eastern part of the bahariya concession and to integrate this data with that obtained from the seismic sections. 2. materials and methods altogether 40 seismic sections were interpreted in order to illustrate the structural framework and depositional history of the study area. these seismic lines were supported by the composite, velocity and vertical seismic profi le (vsp) logs of eight selected wells (aqsa-1x, aqsa-2x, karamae-1x, karama-3x, karama-sw-1x, karama -sw10x, karama-nw-1x and karama-nw-x). cuttings from fi ve wells were selected for biostratigraphic studies that include several species of planktonic foraminifera and calcareous nannofossils. table 1: shows the number and depth of the cuttings from the studied wells. wells depth interval (m) no. of samples aqsa-1x 338.4–2640 40 karama-e-1x 365–2830 40 karama-3x 365–2470 40 karama-nw-1x 430–2600 40 karama-nw-5x 450–2600 40 3. stratigraphy the surface of the northern part of the western desert is covered by miocene deposits, except for the bahariya and abu roash areas that are covered with upper cretaceous and eocene sediments (fig. 2). in the fayium area both eocene and oligocene limestones, clays and sandstones dominate the section. in the bahariya and fayium areas oligocene volcanic basalt makes up a substantial part of the geological succession. the miocene deposits are subdivided into the lower miocene moghra formation and the middle miocene marmarica formation (said, 1962). based on the surface geological map of the western desert, the miocene deposits are separated from the eocene rocks in the south by a narrow band of oligocene carbonates at siwa (harpe de la, 1883) while in al arag there is a gradual southerly change into a clastic succession at bahariya and fayium (osman, 2003). the miocene surface usually doesn’t usually refl ect structures at depth as an angular unconformity is observed at many places separating the miocene and underlying eocene deposits. the upper eocene deposits occupied mainly the figure 1: location map of the area under study (a, b). figure 2: generalized lithostratigraphic column in the abu gharadig basin. mahsoub et al.: bioand sequence stratigraphy of upper cretaceous – palaeogene rocks, east bahariya concession, western desert, egypt geologia croatica 111 central and the south eastern parts of the western desert. these marine deposits are mainly limestone represented by the thebes and farafra formations, the former representing an open marine facies while the latter is a shallow shelf lithofacties (said, 1960). the cretaceous deposits are mainly located at the southern part of the western desert and they consist mainly of the nubia formation. 3.1. subsurface stratigraphy of the western desert the subsurface lithostratigraphic column in the northern part of the western desert contains most of the sedimentary section from pre-cambrian basement rocks to recent deposits. the total thickness of the sedimentary section measures about 4270 m (younes, 2003). figure 2 summarizes the main stratigraphic units in the abu gharadig basin of the western desert. 3.1.1. upper cretaceous rocks in egypt, the upper cretaceous is marked by the beginning of a major marine transgression which resulted in the deposition of a carbonate dominated section in the study area. according to issawi et al. (1999), the upper cretaceous succession is subdivided into three lithostratigraphic units from the oldest bahariya, to the abu roash and the khoman formations. the sedimentary rocks of the upper cretaceous occur in three basins of the western desert; the abu gharadig, shushan, and alamin basins, which include the most important hydrocarbon resources in the western desert. the formations are discussed from oldest to youngest below. 3.1.1.1. bahariya formation the type locality of this unit is located in the gabel el dist (bahariya oasis) where the base of the formation is not exposed at the surface. the maximum thickness of this formation occurs in the kattaniya-1 well (1143 m) (29° 49'n and 30° 10'e). the name of this unit was proposed by said (1962), stromer (1914a, b) and smith et al., 2006 based on dinosaurs remain for the lower cenomanian fl uvio-marine (catuneanu, 2006) sediments which consist of argillaceous sandstone with some carbonates. 3.1.1.2. abu roash formation the type locality of the abu roash formation outcrops to the north of the pyramids of giza (30° 2' 44.59“n and 31°14' 24.71“e). this unit is subdivided into seven lithostratigraphic members, termed from top to bottom as a, b, c, d, e, f, and g, which extend from the santonian to the upper cenomanian. most of the facies were deposited under neritic to open marine, basinal conditions. the abu roash represents the alternation of transgressive and regressive phases, characterized by: 1. shallow to deeper marine carbonates on palaeohighs. the limestones-were dolomitized and have fracture porosity. 2. shallow deposits, consisting of the alternation of shales and sandstones. during turonian times, an evaporitic sequence was deposited in some areas. lithologically, this unit consists of white moderately hard fossiliferous, cherty, massively bedded, micro-to cryptocrystalline chalky limestone. the shales are gray, dark brown and greenish in colour with moderate hardness, containing some glauconite and pyrite. dolomite is brownish in colour, buff, massive and moderate in hardness. this refl ects a nearshore or sabkha type of depositional environment. 3.1.1.3. khoman formation the type section of this unit is located at ain khoman, southwest of the bahariya oasis. it represents an open marine facies which prevailed in the north western desert during the campanian and maastrichtian and it unconformably overlies the abu-roash fm., particularly in the structurally highest area. lithologically this formation consists of two main units: the lower unit is mostly limestone interbedded with shale, the limestone is massive, white dolomitic limestone and the shale is brownish, gray with medium hardness while the upper, unit is of fi ne-grained white chalky massive limestone and massive dolomite and lacks of adequate reservoir properties. 3.1.2. cenozoic rocks at the end of cretaceous, sedimentation in the western desert was continuous in the structurally low and subsiding areas while some depositional gaps and erosional truncations were common on the pre-existing highs, which were reactivated, especially during the palaeocene (schlumber ger, 1984). palaeogene rocks include the palaeocene to middle eocene apollonia fm. which consists mainly of shallow to open marine carbonates. the upper eocene to oligocene dabaa fm. consists of shallow marine shales and the miocene moghra fm. consists mainly of shallow to marginal marine sandstones with thin shale interbeds and a basalt extrusion near its top. the basal part of the moghra fm. laterally changes to carbonates (shoushan formation) in the north west portion of the western desert. the oligo-miocene rocks are also overlain by the middle miocene marmarica fm. to the northwest of the western desert, which consists of shallow marine carbonates (norton, 1967; abdel aal & moustafa, 1988). quaternary deposits unconformably overlie the miocene rocks and consist of plio-pleistocene continental sands. 3.1.2.1. the apollonia formation this is a widespread limestone with subordinate shale of palaeocene to eocene age. the type locality is located south of the village of susa (32° 53' 48“n and 21° 57' 47“e) in libya. the type section is 250 m thick and is made up of massive siliceous limestones with numerous chert bands. the lithology is white, chalky limestone, in many places nummulitic, with some shaly zones, especially where the formation is thick. glauconite and pyrite are common and widespread. chert nodules occur, and are common in the lower part. the formation has been subdivided by several operators into units a to d where d is the oldest. units b and d are thinner and dominanted by shale. geologia croatica 65/2geologia croatica 112 3.1.2.2. the dabaa formation the type section is the interval 579 to 1021 m interval of the dabaa-1 well. lithologically it is composed of gray and greenish-gray clay and claystone with subordinate thin beds of limestone, glauconite and pyrite minerals, of upper eoce ne to oligocene age. the majority of the wells drilled in the study area revealed the same stratigraphic column of the north-western desert with a few exceptions in the variations of thickness and the absence of some rock units. 4. biostratigraphy cuttings from fi ve wells (aqsa-1x, karama-e-1x, karama-3x, karama-nw-1x and karama-nw-5x) were selected for study and the identifi cation of microfossils. several species of planktonic foraminifera and calca reous nannofossils have been identifi ed. some stra ti grap hi cally important taxa are illustrated (figs. 8–11 and figs. 17–21). calcareous nannofossils were processed by the standard smear slide preparation from raw sediment samples as described by perch-nielsen (1985). smear slides were examined using a light photomicroscope with 1250x objective. a relative abundance of calcareous nannofossils was used as follows: a= abundant more than 5 specimens /fi eld of view (fov), c= common 1–5 specimens/fov, f= frequent one specimen /2–5 fov, r= rare one specimen/6–10 fov and vr= very rare one specimen/more 10 fov. 4.1. planktonic and benthic foraminifera the planktonic foraminifera were used to date the different successions of the studied wells. most successions range in age from the cretaceous (cenomanian) to the oligocene. planktonic and benthic foraminifera are encountered only in the marine upper half of the succession which is represented, in ascending order, by the khoman fm, the apollonia fm, and the dabaa fm. 4.1.1. preparation technique samples were soaked in hexametaphosphate solution and then washed through a 0.64 mm sieve. the operation was repeated until the residue became clean. hard samples were then treated by ultrasonic cleaner. foraminiferal specimens were picked and mounted on squared slides for identifi cation. figure 3: distribution chart of the planktonic and benthic foraminifera of the well aqsa-1x. mahsoub et al.: bioand sequence stratigraphy of upper cretaceous – palaeogene rocks, east bahariya concession, western desert, egypt geologia croatica 113 4.1.2. the khoman formation the khoman formation contains planktonic and benthic foraminiferal assemblages of campanian – maastrichtian age (figs. 3 to 7). the faunal assemblages of the khoman fm. belong to the following planktonic foraminiferal zones, from base to top, as follows: globotruncana ventricosa zone, g. aegyptia ca zone (caron, 1985; caron et al., 2006 and berg gren & pearson, 2006) and gansserina gansseri zone which are assigned to the upper campanian to maastrichtian. 4.1.3. apollonia formation the apollonia formation unconformably overlies the khoman formation. it consists mainly of limestone with occasional argillaceous interbeds in some wells. it is relatively poor in foraminifera and almost barren at some levels. accordingly, systematic biozonation is diffi cult and impractical to establish, especially due to the absence of some key species (figs. 3 and 7). however, some other species have helped in establishing different age divisions of the apollonia formation figures 3 to 7 shows the distribution of planktonic foraminifera in the apollonia formation of the different wells. the lower/middle eocene boundary has been drawn at the fi rst appearance of middle eocene species such as acarinina bullbrooki especially when associated with catapsydrax sp and turborotalia cerroazulensis pomeroli. the lower eocene is estimated according to the occurrence of only lower eocene species such as morozovella formosa, acarinina soldanii, & acarinina pentacamerata. these three species together with acarinina broedermanni represent the assemblage of the lower eocene (bolli, 1957; toumarkine & luterbacher, 1985; berggren & pearson, 2006). they are usually followed by a barren interval before the inception of the middle eocene species. accordingly, the lower/middle eocene boundary here is speculative rather than factual. the middle eocene part is the interval richest interval in foraminifera. all the species of the assemblage support this age determination based on comparison with those mentioned in the literature (bolli, 1957 & blow, 1979; toumarkine & luterbacher, 1985; berggren & pear son, 2006). it is worth mentioning, however, that except for acarinina and truncorotaloides, the range of these species extends to the upper eocene. yet, the index species of the upper eocene, globigerinatheka semiinvoluta, is used to delineate the upper eocene upon its occurrence. this species appears in some wells (figs. 3 and 5) and is absent in others (figs. 4, 6 and 7). the latest eocene fauna such as cribrohantkenina, t.c. cocoaensis, t.c. cunialensis are absent from the material sugfigure 4: distribution chart of the planktonic and benthic foraminifera of the well karama-3. geologia croatica 65/2geologia croatica 114 gesting that the upper eocene when observed is incomplete. accordingly, the boundary between the apollonia fm. and the underlying khoman fm. is represented by a hiatus spanning the whole palaeocene and the basal part of the eocene with some hiatuses within the formation. the recorded plank tonic foraminiferal zones: from the morozovella aragonensis zone (p8, bolli, 1957 and toumarkine & luterbacher, 1985) to the globigerinatheka semiinvoluta zone (p15, bolli, 1957) are delineated within the apollonia fm. with the pronounced unconformity with the overlying dabaa fm. 4.1.4. the dabaa formation the dabaa fm. is devoid of identifi able planktonic foraminifera in spite of the sporadic occurrence of benthics species. so, its oligocene age, as estimated by sporadic fau na, is adopted here. the planktonic and benthic species are shown in figures 8 to 11. 4.2. nannoplankton biostratigraphy the zonations of sissingh (1977) for the upper cretaceous and that of martini (1971) and okada & bukry (1980) for the lower palaeogene were adopted here in the deep wells, contamination by caving is observed through examination of the cutting. in the study wells, nannofossils are frequent to rare and moderately to poorly preserve. in the following, the recognized nannofossil biozones are discussed from, base to top. abbreviations used are: fo = first occurrence, lo = last occurrence. fo is used following the standard biostratigraphic scheme but taking into consideration that the samples are cuttings; the law of fi rst appearance is applied accordingly. 4.2.1. upper cretaceous calcareous nannofossil biostratigraphy 4.2.1.1. quadrum trifi dium zone (cc22) defi nition: it is defi ned as the interval from the fo of quadrum trifi dium to the lo of reinhardtites anthophorous. authors: bukry & bramlette (1970), emended by sissingh (1977) age: late campanian. occurrence: aqsa-1x (1590–1800 m), karama-3x (1500–1550 m), karama-nw-1x(1450–1650 m) (in khoman formation). figure 5: distribution chart of the planktonic and benthic foraminifera of the well karama-e-1x. mahsoub et al.: bioand sequence stratigraphy of upper cretaceous – palaeogene rocks, east bahariya concession, western desert, egypt geologia croatica 115 figure 6: distribution chart of the planktonic and benthic foraminifera of the well karama-nw-1x. figure 7: distribution chart of the planktonic and benthic foraminifera of the well karama-nw-5x. geologia croatica 65/2geologia croatica 116 figure 8: planktonic eocene plate. 1 – morzovella subbotinae morozova, 1929; 3690 ft, karama-nw-1x. 2 – globigerina eocaena guembel1966; 1650 ft, aqsa-1x. 3 – acarinina crassata cushman, 1962; 2430 ft, aqsa-1x. 4 – globigerina pseudoampliapertura (bow, banner, 1962); 2130 ft, karamanw-1x. 5–7 – acarinina crassata, toumarkine, bolli, (1970); 1800 ft, aqsa-1x. 8 – turborotalia cerroazulensis possagnoensis, toumarkine, bolli, (1970); 2430 ft, karama-3x. 9–11 – turborotalia cerroazulensis pomeroli, toumarkine, bolli, (1970); 1890 ft, karama-3x. 12 – turborotalia cerroazulensis bolli, (1970); 1830 ft, karama-e-1x. 13 – globigerinatheka index (fi naly, 1939); 1770 ft, karamae-1x. 14,15 – globigerinatheka tropicalis (blow, banner, 1962); 2130 ft, karamanw-1x. 16 – globigerinatheka semiinvoluta (keijzer, 1945); 1830 ft, karamae-1x. remarks: in addition to the zonal marker, the nannofossil assemblage includes: watznaueria barnesae, cyclagelosphaera reinhardtii, lucianorhabdus. cayeuxii, cribrosphaerella ehrenbergii, aspidolithus parcus, eiffellithus eximius. 4.2.1.2. tranolithus phacelosus zone (cc23) defi nition: it is defi ned from the lo of reinhardtites anthophorus to the lo of tranolithus phacelosus. authors: sissingh (1977) age: late campanian to early maastrichtian. occurrence: karama-3x (1370–1435 m), karama-nw1x (1150–1420 m) (in khoman formation). remarks: in addition to the zonal markers, the nannofossil assemblage includes the large sized forms of eiffellithus turiseffelii and arkhangleskiella cymbiformis. 4.2.1.3. arkhangleskiella cymbiformis zone (cc25) defi nition: it is defi ned from the lo of reinhardtites levis to the fo of nephrolithus frequens. authors: perch – nielsen (1972), emended by sissingh (1977) age: late maastrichtian. occurrence: aqsa-1x (1400–1540 m), karama-nw-5x (1700–1400 m) (in khoman formation). remarks: the cc25 zone is unconformably overlain by zone np12 (early eocene), with a marked hiatus spanning the uppermost maastrichtian, as well as the entire palaeocene and the lower part of the lower eocene. 4.2.2. lower palaeogene calcareous nannoplankton biostratigraphy 4.2.2.1. tribrachiatus orthostylus zone (np12) defi nition: the base is defi ned by the fi rst occurrence (fo) of discoaster lodoensis and the top by the last occurrence of tribrachiatus orthostylus. authors: brönnimann & stradner (1960) age: early eocene (ypresian). mahsoub et al.: bioand sequence stratigraphy of upper cretaceous – palaeogene rocks, east bahariya concession, western desert, egypt geologia croatica 117 figure 9: planktonic cretaceous plate. 1 – heterohelix navarroensis (loeblich, 1951); 4320 ft, karama-3x. 2,3 – heterohelix globulosa (ehrenberg, 1840); 3630 ft, karama-nw-5x. 4 – heterohelix sp. 3810 ft, karama-nw-5x. 5,6 – rugoglobigerina macrocephala bronnimann, 1952; 4320 ft, karamanw-1x. 7 – rugoglobigerina scotti (bronnimann, 1952); 4530 ft, karama-nw-1x. 8 – rugoglobigerina sp. 4770 ft, karama-3x. 9 – rugoglobigerina rugosa (plummer, 1926); 3930 ft, karama-3x. 10 – globotruncanella sp. 3810 ft, karama-nw-5x. 11 – globotruncanella petaloidea (gandolfi, 1955); 4620 ft, karama-e-1x. 12–14 – globotruncana linneiana (d,orbigny, 1839) ); 4710 ft, karama-3x. 15,16 – globotruncana cf. falsostuarti sigal, 1952; 5520 ft, karama-e-1x. 17,18 – globotruncana sp. 4830 ft, aqsa-1x. 19 – globotruncanita stuarti (de lapparent, 1918); 4710 ft, karama-3x. 20,21 – globotruncanita cf. stuartiformis (dalbiez, 1955); 4770 ft, karama-nw-5x. 22,23 – hedbergella cf. holdelensis olsson, 1964; 4110 ft, karama-3x. 24 – hedbergella delrioensis (carsey, 1926); 4620 ft, karama-3x. 25 – globotruncana cf. aegyptiaca nakkady, 1950; 3930 ft, karama-nw-x. 26 – rosita (contusotruncana) fornicata (plummer, 1931); 5940 ft, aqsa-1x. 27 – rosita (contusotruncana) contusa (cushman, 1926); 3780 ft, karama-nw-1x. occurrence: karama-e-1x (600–700 m), karama-nw1x (600–700 m), karama-nw-5x (650–660 m) (in apollonia formation). remarks: in addition to the zonal markers, the nannofossil assemblage includes in the investigated wells the fo of both scyphosphaera magna and ericsonia formosa which defi ne the base of np12. 4.2.2.2. discoaster lodoensis zone (np13) defi nition: lo of tribrachiatus orthostylus or fo of toweius crassus to the fo of d. sublodoensis. assemblage: the characteristic assemblage in clu des: coccolithus pelagicus, ericsonia formosa, helicos phae ra lophota, pontosphaera multipora, sphenolithus moriformis, pontosphaera multipora, chiasmolithus solitus, discoaster geologia croatica 65/2geologia croatica 118 barbadiensis, reticulofenestra dictyoda, helicosphaera lophota, and neococcolithes dubius. authors: brönnimann & stradner (1960) and bukry (1973) age: early eocene (ypresian). occurrence: karama-3x (800–1180 m) remarks: in addition to the zonal marker, the nannofossil assemblage includes (in the base of the zone) the fo of reticulofenestra dictyoda and helicosphaera lophota. its top cannot be defi ned due to the marked hiatus which includes zones np14 through np17 in karama-nw-5x. 4.2.2.3. discoaster tani nodifer zone (np16) defi nition: this zone includes the stratigraphic interval from the lo of rhabdosphaera gladius to the lo of chiasmolithus solitus. assemblage: besides the nominated species, zone np16 includes: ericsonia formosa, helicosphaera lophota, figure 10: benthic cretaceous plate. 1 – gyroidinoides depressus (hagenow); 3930 ft, karama-nw-1x. 2,3 – gavelinella monterelensis 4140 ft, karamanw-1x. 4 – stensioeina pommerana brotzen; 4380 ft, aqsa-1x. 5 – coryphostoma cf. gemma cushman 1927; 4380 ft, aqsa-1x. 6 – corphostoma crassum vasilenko, myatlyuk 1947; 7–9 – globorotalites conicus carsey 1926; 3780 ft, karama-nw-1x. 10,11 – cibicidoides sp.; 4470 ft, karama-e-1x. 12 – gyroidina sp.; 3990 ft, karama-nw-5x. 13 – gavelinella sp.; 3810 ft, karama-nw-5x. 14,15 – arenobulimina sp.; 4380 ft, aqsa-1x. 16 – dorothia retusa kamimski et al. 1988; 4710 ft, karama-3x. 17 – bolivinoides draco (marsson, 1878). 18 – cibicides sp. 19 – laevidentalina cf. catenula cushman &jarvis 1932. 20,21 – anomalinoides sp.; 4620 ft, aqsa-1x. 22 – gaudryina laevigata frank 1914; 3990 ft, karama-nw-5x. mahsoub et al.: bioand sequence stratigraphy of upper cretaceous – palaeogene rocks, east bahariya concession, western desert, egypt geologia croatica 119 pontosphaera multipora, sphenolithus moriformis, pontosphaera multipora, chiasmolithus solitus, discoaster barbadiensis, reticulofene stradictyoda, neococcolithes dubius, reticulofenestra hampdenensis, cribrocentrum reticulatum, sphenolithus moriformis, and reticulofenestra umbilica. authors: hay et al. (1967), emend martini (1970) age: middle eocene occurrence: karama-nw-1x (705–760 m), aqsa-1x (805–1080 m), karama-3x (810– 1180 m) (in the apollonia formation). remarks: the base of the zone is placed at the level of the fi rst appearance of reticulofenestra umbilica in the studied wells. rhabdosphaera gladius, the marker of the base of the zone is often of little use for zonation (perchnielsen, 1985, p. 439). it is well known that reticulofenestra umbilica has its fo at the base of the middle eocene zone np16 (martini, 1971) and cp14 (okada & bukry, 1980). in the study wells, a large scale hiatus is recorded below and above the sediments of zone np16, and thus the top and ba se of zone np16 cannot be accurately detected in such wells. 4.2.2.4. chiasmolithus oamaruensis zone (np18) defi nition: this zone is defi ned as the interval from the fo of chiasmolithus oamaruensis to the fo of isthmolithus recurvus. assemblage: the zone includes the following nannofossil taxa:,pemma basquensis, discoaster tanii, pemma pafigure 11: benthic eocene plate. 1 – cancris auriculus fitchtel, moll, 1798; 1890 ft, karama-nw-1x. 2 – hanzawaina sp. 2100 ft, aqsa-1x. 3 – cibicidoides ungerianus 2130 ft, karama-nw-5x. 4 – cibicidoides kullenbergi parker, 1953; 2160 ft, karama-3x. 5 – nonnion scaphum fitchtel, moll, 1798; 1950 ft, karama-3x. 6 – lenticulina sp.1530 ft, karama-3x. 7 – planulina sp. 1800 ft, aqsa-1x. 8 – uvigerina eocaena gumbel, 1868; 1650 ft, aqsa-1x. 9 – bulimina jacksonensis cushman, 1925; 1800 ft, aqsa-1x. 10 – bulimina alazanensis cushman, 1927; 1890 ft, karama-nw-1x. 11 – nodosaria sp. 1890 ft, karama3x. 12,13 – uvigerina tempoalae boersma, 1984; 1740 ft, karama-nw-1x. 14,15 – eponides ellisoare seguenza, emend, 1968; 1830 ft, karama-e-1x. 16 – quinqueloculina seminula linne, 1958; 1620 ft, karama-e-1x. 17 – baggina sp. 2430 ft, karama-e-1x. geologia croatica 65/2geologia croatica 120 pillatum, reticulofenestra hillae, cribrocentrum reticulatum, reticulofenestra umbilica, helicosphaera compacta, discoaster tanii,discoaster tanii nodifer, ericsonia formosa, reticulofenestra dictyoda, reticulofenestra hampdenensis, reticulofenestra hillae and chiasmolithus oamaruensis. authors: martini (1970) age: middle to late eocene. occurrence: karama-nw-5x, aqsa-1x (560–1400 m), karama-3x (660–740 m), karama-e-1x (795–1250 m) (in apollonia formation). remarks: the base and top of zone np18 are well defi ned in karama-3x, karama-e-1x and karama-nw-5x. 4.2.2.5. isthmolithus recurvus zone (np19/20) defi nition: the interval from the fi rst occurrence of isthmolithus recurvus to the last occurrence of discoaster sai panensis,and /or discoaster barbadiensis. assemblage: zone np19-20 includes isthmolithus recurvus, pemma basquensis, reticulofenestra dictyoda, discoaster tanii, reticulofenestra hampdenensis, reticulofenestra hillae,cribrocentrum reticulatum, sphenolithus mo ri formis, and reticulofenestra umbilica. authors: hay, mohler & wade (1966), emended martini (1970). age: late eocene. occurrence: karama-3x (570–595 m), karama-e-1x (630–700 m), karama-nw-1x (620–705 m), karama-nw5x (650–680 m) (in apollonia formation). remarks: the fi rst occurrence of isthmolithus recurvus marks the base of the combined zone np19/20. martini (1971) used the lowest occurrence of sphenolithus pseudoradians to defi ne the base of zone np20, but subsequent work (martini, 1976) has shown that s. pseudoradians occurs much earlier and that the two zones cannot be differentiated. therefore, zones np19 and np20 are also combined here, and zone np19/20 is defi ned as the interval between the fi rst occurrences of i. recurvus and the last occurrence of discoaster saipanensis and d. barbadiensis. figures 12 to 16 show the distribution of the nannoplankton in the different wells and some stratigraphically important taxa are represented in figures 17 and 18 which are identifi ed from the aqsa-1x, karama-3x, karama-e-1x, karama-nw-1x and karama-nw-5x wells respectively. figure 12: distribution chart of the nannofossils of the well aqsa-1x. mahsoub et al.: bioand sequence stratigraphy of upper cretaceous – palaeogene rocks, east bahariya concession, western desert, egypt geologia croatica 121 figure 13: distribution chart of the nannofossils of the well karama-3x. 5. sequence stratigraphy the target of seismic stratigraphic analysis is to divide the seismic sections of the east bahariya concession into distinct depositional sequences that make up the investigated late cretaceous-eocene succession in the study area. these sequences are bounded from above and below by marked sequence boundaries (emery & myers, 1996). the following steps were followed to achieve the aim of this study: a) reorganization of the time-depositional units depending on the detected unconformities or changes in seismic patterns. b) following these recognized unconformities in the different investigated seismic sections, it was important to defi ne the major sequence boundaries. c) seismic facies analysis, interpreting depositional environments from seismic refl ection characteristics. d) sequence stratigraphic analysis of the different formations using the available biostratigraphic data and lithological composition. 5.1. detailed sequence stratigraphic analysis analysis of the sequence stratigraphy in the studied area is based mainly on the interpretation of various key surfaces (sequence boundaries (sb), transgressive surfaces (ts), transgressive surfaces of erosion (tse) and maximum fl ooding surfaces (mfs)) and system tracts (lowstand systems tracts (lst), transgressive systems tracts (tst), highstand systems tracts (hst)) well logs (natural, radioactivity, receptivity and density logs) and foraminiferal content. these factors detect the depth and the environmental conditions during deposition in the seven investigated wells (aqsa-1x, aqsa-2x, karama-3x, karama-e-x, karama-nw-1x, karama-nw-5x, karama-sw-1x and karama-sw-10x) located in the studied east bahariya concession (figure 1). the studied upper cretaceous-eocene succession in the east bahariya concession at the western desert is subdivided into fi ve major 2nd order depositional sequences (ucs1, geologia croatica 65/2geologia croatica 122 figure 14: distribution chart of the nannofossils of the well karama-e-1x. ucs2, ucs3, es and ors). these are separated by four major depositional sequence boundaries (sb1, sb2, sb3 and sb4) as shown in (figs. 19 and 20). 5.1.1. upper cretaceous sequence 1 (ucs1) (cenomanian) the fi rst sequence (ucs1) is represented by the upper cretaceous rocks including the upper bahariya fm. (fig. 19). the top of this sequence is bounded by the depositional sequence boundary sb1 which represents the boundary between the abu roash-g member and the underlying bahariya fm. it is the deepest identifi ed and selected surface in the study area, which regionally, extends along the east bahariya concession, indicating a regional unconformity between the abu roash formation and the underlying bahariya formation and the second order depositional sequence boun dary (el bassyouny, 1970, catuneanu et al., 2006). the base of this sequence can not be followed on the seismic sections because these are badly processed (fig. 21), while the upper part of the bahariya fm. displays discontinuous, moderate to low amplitude refl ectors. internal confi gurations including onlap, toplap, downlap and parallel refl ectors were recognized. the external form of this sedimentary body appears either as sheet-like or wedge-shaped units. the principal internal confi gurations appear to be parallel to subparallel. interpretation clear differences between the high and low to moderate amplitude refl ectors in this formation testify to the existence of at least two different lithological units. one has high amplitude and displays parallel to divergent refl ector terminations. these units are interpreted as shale to siltstone beds. the other lithological units which have a low to moderate amplitude and are characterized by disconnected refl ectors are interpreted as sandstone beds. according to darwish et al., (1994) and ismail et al. (1989) the bahariya formation lithologically is subdivided into the lower bahariya and upper bahariya units. mahsoub et al.: bioand sequence stratigraphy of upper cretaceous – palaeogene rocks, east bahariya concession, western desert, egypt geologia croatica 123 figure 15: distribution chart of the nannofossils of the well karama-nw-1x. the lower bahariya formation is composed of a relatively sand rich succession of fi ne to medium grained sandstone and shale while the upper bahariya formation is composed mainly of very fi ne-grained sandstone with shale intercalated with limestone beds. pyrite and glauconite minerals are common, which were deposited in a shallow marine to fl uvio-marine environment with alternating high and low energy. based on the results of the analyzed seismic lines, this subdivision of the bahariya fm. into two units has been identifi ed in the all investigated seismic lines thus confi rming the interpretation of the seismic facies. 5.1.2. upper cretaceous sequence 2 (ucs2) (cenomanian–turonian) 5.1.2.1. abu roash-g member (cenomanian) based on the interpretation of the seismic lines, the abu roash-g member can be subdivided into two main parts. the lower part is characterized by low amplitude and mo dera te continuity refl ectors. their refl ection geometry at the sequen ce boundaries is considered as erosional truncation (fig. 23). from the studied seismic lines the refl ection geometry at the sequence boundaries are considered concordant with lower and upper sequence boundaries of this formation. the seismic facies of the lower part of the abu roash-g member appears as low to moderate amplitude and moderate continuous refl ectors in the internal confi guration as parallel refl ectors, which in the external outline seems to represent elongated wedge-shaped beds. the seismic facies of the upper part of the abu roashg member is characterized by high amplitude and very continuous refl ectors. the internal refl ection geometry at the upper sequence boundary is considered concordant and runs parallel to the sequence boundary (figs. 21 and 23). interpretation the characteristic confi guration of the seismic facies in the lower part of the abu roash-g member is interpreted as sand geologia croatica 65/2geologia croatica 124 figure 16: distribution chart of the nannofossils of the well karama-nw-5x. figure 17: nannofossils cretaceous plate. 1 – eiff ellithus turriseiff elii (deflandre in deflandre & fert, 1954) reinhardt (1965) k-nw-1x; 2,3 – lu cianorhabdus cayeuxii delandre (1959), depth (5040-5070) aqsa-1x; 4,5 – calculites obscurus (deflandre, 1959), depth (4470-4500) k-3x; 6 – reinhardtites anthophorus (deflandre, 1959), depth (5640-5670) k-e1x; 7 – cribrosphaerella ehrenbergii (arkhangelsky, 1912), depth (51005130) k-nw-1x; 8 – eiff ellithus eximius (stover, 1966) depth (5850– 5880) k-e-1x; 9,10 – micula murus martini (1961), depth (4470–4500) k-3x; 11,12 – watznaueria barnesae (black in black & barnes, 1959), depth (5935–5940) aqsa-1x. bars (fig. 23). the low amplitude and discontinuity of the seismic refl ectors support this interpretation. these sand beds may represent deposits of a prograding delta system, with offshore (pro-delta) silty mudstones at the base overlain by (in ascending order) lower, middle and upper shoreface sandstone, distributary-mouth bar sandstone. the internal confi guration as parallel refl ectors of the upper part is interpreted as homogenous sediments, which are arranged in parallel thin beds. these features exhibit cycles of mudstone, glauconitic siltstone, limestone, and sandstone deposits. based on the depositional environment of the abu roash-g member (mark et al., 2009) which is conside red mahsoub et al.: bioand sequence stratigraphy of upper cretaceous – palaeogene rocks, east bahariya concession, western desert, egypt geologia croatica 125 figure 18: nannofossils paleogen plate. 1 – reticulofenestra hillae bukry & percival (1971) aqsa-1x; 2 – ismolithus recurvus deflandre (1959), depth (1920–1950) k-3x; 3 – pemma basquensis (martini, 1959c) baldibeke (1971) k-nw-1x; 4 – reticulofenestra umbilica (levin, 1965), depth (2400–2430) aqsa-1x; 5 – pontosphaera multipora (kamptner, 1948) roth (1970) k-nw-1x; 6 –bismolithus recurvus deflandre 1959 k-e-1x; 7 – braarudosphaera bigelowii (gran & braarud, 1935), depth (2130– 2160) k-3x; 8 – dictyococcites bisectus (hay, mohler, wade, 1966), depth (1920–1950) k-3x; 9 – ismolithus recurvus deflandre (1959), depth (1920–1950) k-3x; 10 – ericsonia formosa (kamptner, 1963), depth (2400–2430) k-nw-5x; 11 – zygrhablithus bijugatus (deflandre in deflandre & fert, 1954), depth (2640–2670) k-3x; 12 – chiasmolithus oamarunsis (dellandre, 1959), depth (2400–2430) k-3x; 13 – mi crantholithus bramlettei (bronnimann & stradner, 1960), depth (3390– 3420) k-3x; 14 – sphenolithus radians deflandre in grasse (1952), depth (3390–3420) k-3x; 15,16 – pontosphaera multipora (kamptner, 1948), depth (2400–2430) k-3x. figure 19: an interpretation of seismic section 5455. to be delta to shallow marine environment, our interpretation agrees with the statements and characteristic features such as sandstones bodies and shale beds that were re cog nized in the interpreted seismic lines (figs. 21, 23 and 24). 5.1.3. abu roash a, b, c, d, e and f members (turonian) the abu roash fm. is generally characterized by several strong correlated internal refl ectors representing the contacts between its members. the parallel refl ectors alternate with weak to moderate internal refl ectors, which show chaotic to hummocky internal confi gurations (fig. 24). the external forms of these members (a, b, c, d, e and f) display different geometries such as sheet-like and wedge-shaped forms, which can be indicated by parallel to divergent internal refl ection confi guration. based on biostratigraphy barakat et al. (1987), these facies features exhibit cycles of shallow marine limestone, sandy limestone and shale of the abu roash a, shallow of the abu roash b member, relatively restricted deep marine shale, sandstone and limestone of the abu roash c member, the limestone and shale of abu roash d, shallow marine figure 20: an interpretation of seismic section 1417. sand and shale of the abu roash e member, and the deep marine limestone and shale of the abu roash f member (figs. 23 and 25). interpretation the alternation between weak –moderate and high amplitude internal refl ectors suggests at least two different lithological units. the obvious parallel refl ectors are interpreted as shale beds. the low amplitude refl ectors have a chaotic to hummocky internal confi gurations, which indicate impure limegeologia croatica 65/2geologia croatica 126 stone or highly bioturbated sandstone beds. the abu roash fm. of turonian age consists of limestone with shales and sandstone intercalations providing a good source reservoir and cap rocks for hydrocarbons (bayoumi et al., 1987). according to barakat (1987) the habitats of the faunal assemblage together with the occurrence of detrital quartz grains in the abu roash f-a members suggest a shallow marine environment of the neritic zone. furthermore the abu roash fm. was deposited in shallow-shelf to open-marine conditions (barakat et al., 1987; bayoumi et al., 1994, 1996). 5.1.4. upper cretaceous sequence 3 (ucs3) (campanian-maastrichtian) the khoman fm. is equivalent to sequence (ucs3). this sequence is bounded by sb2 below and the above. sb2 is at the end of the turonian. detailed analysis of sb2 reveals that it is of the type 2 boundary of van wagoner et al. (1988). it is characterized by partial erosion of the coniacian and santonian between the khoman and the top of the abu roash formation, as shown by truncation of the top abu roash especially in structurally uplifted places (bayoumi & lotfy, 1989). it is an important disconformity recorded in all the cretaceous-tertiary successions of egypt (hewaidy et al., 2006). the seismic facies of the lower part of the khoman fm. is moderate to low in the continuity and amplitude represented by disconnected refractors. these refl ectors exhibit several characteristic terminations such as onlap, truncations and complicated sigmoidal confi gurations. a group of parallel irregular refl ectors is characteristic for this lower part of the khoman fm. figure 21: lithologic section of the upper cretaceous-eocene succession correlated with seismic profi le 1219. the seismic facies of the middle part of the khoman fm. is entirely different in character which is dominated by very weak continuity and amplitude with prevailing chaotic seismic confi gurations (fig. 26). the external geometry of this part represents an inhomogeneous lithological character, which appears to be similar to reef or salt dome geometry (fig. 26). the internal configuration of the upper part of the khoman formation is characterized by very high continuity and amplitude with parallel refl ectors. these refl ectors extend concordantly with the upper boundary of this sequence and display onlap and oblique parallel confi gurations. the external geometry in the upper part occurs as sheet like units to platform geometry especially to the north of the study area (fig. 26). interpretation based on the fossil content and the description of the seismic facies with respect to characteristics of these seismic refl ectors, one could conclude that the logical interpretation of the seismic confi guration, such as very closed and parallel refl ectors, indicate a well bedded and homogenous lithology, which can be shale beds intercalated with limestone or chalk. parallel, irregular refl ectors groups are interpreted as isoclinals small folds within the lower part of the khoman fm. fold structures can be attributed to compressional stress in the study area during the late cretaceous. the poorly and weak amplitude refl ectors in the middle part indicate massive chalk limestone. the moderate to low continuity and amplitude signify limestone with a high number content of chert nodules. this interpretation agrees with the lithology of the khoman fm. which consists mainly mahsoub et al.: bioand sequence stratigraphy of upper cretaceous – palaeogene rocks, east bahariya concession, western desert, egypt geologia croatica 127 figure 22: shows the lower part of seismic line 5667(middle of the study area), (b): the interpreted seismic line 5667 displaying the main internal confi gurations which characterized the seismic facies of upper cretaceous sequence 1 (ucs1). figure 23: shows the lower part of seismic line 5727(middle of the study area), (b): the interpreted seismic line 5775 illustrates the internal confi gurations of sandstone in the lower part of abu roash-g member as a part of upper cretaceous sequence 2 (ucs2). figure 24: showing the lower part of seismic line 5930 (east of the study area), (b): the interpreted seismic line 5930 illustrates the internal confi gurations of sandstone in the lower part of abu roash-g member as a part of upper cretaceous sequence 2 (ucs2). geologia croatica 65/2geologia croatica 128 figure 25: relative sea level fl uctuations in the upper cretaceous, western desert. figure 26: showing one of the internal confi guration which distinguish the seismic facies of upper cretaceous sequence 3 (ucs3) (upper part of line 5667). of chalky limestone with pyritic, cherty strata in the lower part and interbeds of shale in the upper part (barakat et al., 1984, abdel hamid, 1985 & ghanem, 1985). facies characteristics, faunal content and planktonic ratio indicate an upward shallowing in the depositional regime from a deep middle/outer to shallow inner shelf during deposition of the khoman formation (hewaidy et al., 2006). 5.1.5. eocene sequence 4 (es) the fourth sequence is represented by eocene sediments (es), which comprise the apollonia formation (figs. 19, 20). this sequence is bounded by sb3 in the lower part and by sb4 at the upper part figs. 19 & 20, show the sb3 which appears at the end of the upper cretaceous (campanian – maastrichtian) and separates between the eocene sequence (es) and upper cretaceous sequence (ucs3) sequences. the sb3 has moderate to high amplitude refl ectors and is also marked by the radioactivity increase in the gamma ray logs (fig. 27). based on the fossil content, the available data and former geological studies, the lower part of this sequence boundary is affected by submarine erosion causing the erosion causing the removal of the uppermost part of the maastrichtian and all of the palaeocene (bayoumi et al., 1987). seismic facies of this sequence which is represented by sediments of the apollonia formation have three main features which are also very clear in the gamma logs. the seismic facies of the lower part of the apollonia fm. is moderate to low both in continuity and amplitude, while to the north of the area; refl ectors are moderate to high amplitude and continuity. the internal confi gurations appear to be parallel to divergent (fig. 28). this part shows the increase in gamma rays (more than the upper part of the khoman formation). in general the refl ection geometry at the lower sequence boundary of the apollonia sequence is considered concordant and exhibits even onlap near to central part of the study area (fig. 28) the seismic facies of the middle part of the apollonia formation is distinguished by high continuity and amplitude. also the principal internal confi gurations appear to be parallel to the divergent refl ectors. the external form of these sediments is considered to be a wedge like geometry with local irregular bedding features. these structures occur as small isolated and relative high amplitude refl ectors of small domal structures. the seismic facies of the upper part of the apollonia formation is characterized by low to moderate continuity and amplitude. the principal internal confi gurations appear to be parallel to divergent. the external form of these sediments is sheet-like and wedge shaped units. the foraminiferal assemblage recorded from the upper part of this sequence suggests the end of the restricted environment that prevailed during deposition of the underlying eocene sediments. interpretation based on the seismic facies confi gurations the parallel high amplitude refl ectors display a carbonate ramp geometry, which has a very slight dip and occurs as an elongated wedge. the local irregular bedding structures are interpreted as convolute bedding which may be related to slumping. this carbonate ramp extends from north to the south (fig. 28). it is worth mentioning, that the thicknesses of this mahsoub et al.: bioand sequence stratigraphy of upper cretaceous – palaeogene rocks, east bahariya concession, western desert, egypt geologia croatica 129 figure 27: system tracts, logs, fauna and depositional environment of well k-nw-1x. carbonate ramp decreases laterally to the south. the low amplitude refl ectors in the lower part indicate a heterogeneous lithology, which may be related to mixed pure carbonate sediments contaminated with cherty nodules and lenses parallel to bedding. the lithological composition and the characteristics of the seismic refl ectors of this sequence suggest that its depositional conditions range the inner shelf at the base to the outer shelf at the top of this sequence. 5.1.6. oligocene to recent sequence 5 (ors) the oligocene to recent facies in the study area are represented by the sediments of the dabaa fm. in the lower part and the moghra fm (miocene) at the top of the investigated geologia croatica 65/2geologia croatica 130 seismic lines. both formations build up a complete sequence the lower boundary of which is represented by the sequence boundary (sb4), whereas the upper boundary represents the top of all interpreted seismic lines in the study area. the sequence boundary represents the unconformity surface due to erosion of sandstone and siltstone from type section defi ned in the dabaa-1 well (tawadros, 2001). based on the analyzed lines, the seismic facies of the upper top facies are characterized by: internal confi guration of the lower part gradually increasing in both the continuity and frequency of seismic refl ectors upward showing several seismic terminations such as toplap with parallel to sigmoidal confi gurations. these refl ectors run parallel to each other and display a high amplitude and frequency in the middle part of this sequence. the external form of this unit resembles sheet-like units. the upper part of the sequence is characterized by chaotic, discontinuous, high frequency and low amplitude refl ectors (fig. 29). the internal confi guration of the seismic facies is characterized by seismic termination features: onlap, toplap and erosion truncations. the external form is of the sheet-like and wedge shaped units with observable channel-like geometry. interpretation a gradually increase in both the continuity and frequency of the seismic refl ectors in the lower part of this sequence indicates changes in the lithology. hence the lower part of this sequence is interpreted as shale beds of the dabaa formation intercalated with evaporites concentrated in the lower part of the sequence and characterized by low amplitude refl ectors and very chaotic seismic confi guration (fig. 29). the upper part of this sequence is interpreted as sandstone beds of the moghra formation because of the relatively low seismic refl ectors, in addition to the occurrence of typical sandstone features such as channel fi ll structures. these characterize the upper top facies of the dabaa and moghra formations suggesting a change from shallow marine inner shelf environment at the base to fl uvial facies at the top. this assumption agrees in some points with the interpretation of the seismic lines. 5.2. gamma ray response the change in the gamma ray responses in the various units can be recognized. the boundary between units ucs1 and ucs2 is marked by a decrease in the gamma ray values (fig. 30). the presence of sandstone and shale intercalations in many parts of the ucs1 unit causes oscillation of the gamma ray curve (figs. 29, 30). the contact between the units ucs2 and ucs3 can be detected by a decrease in the gamma ray values (figs.20, 29) accompanied with the change from shale to limestone lithofacies. the boundary between the unit ucs3 and the es is marked by a slight increase in the gamma ray values. ucs3 shows no change in gamma ray values because it is composed only of chalk limestone. the es unit shows some high values in the gamma ray log which are ascribed to the shale intercalations in this unit (fig. 29). figure 28: showing the lower part of seismic line 5630 (middle of the study area), (b): the interpreted seismic line 5630 illustrating the internal confi gurations of eocen sequence. mahsoub et al.: bioand sequence stratigraphy of upper cretaceous – palaeogene rocks, east bahariya concession, western desert, egypt geologia croatica 131 the upper part of the ors unit is characterized by a marked decrease in the gamma ray values with respect to the underlying unit es. 6. discussion of the systems tracts the upper cretaceous – palaeogene succession in the east bahariya concession is divided into 17 systems tracts. these systems tracts are outlined below: 6.1. system tracts of cenomanian age 6.1.1. lowstand systems tract (lst1) this systems tract represents the fi rst one studied in this work. it comprises the upper part of the first sequence (ucs1), which represents the upper part of the bahariya formation. the lower boundary of this tract is not traceable on seismic profi les. this lowstand system is characterized by low gr and relatively high resistivity (fig. 30). sediments of the lst1 are mainly sandstones with siltstone interbeds. these deposits are overlain by the clastic and non-clastics deposits of shale and limestones, which belong to the lower part of the abu roash-g member (fig. 31). the available data indicate that this interval represents the maximum drop in sea level. this drop started with the deposition of the coarse clastics (sandstone) of the bahariya formation and continued and increased with deposition of more clastics and evaporites. this systems tract is widely recognized across the western desert. the tst is missing, due to either non-deposition or subsequent erosion. the hst of this sequence is also missing, most likely due to subaerial erosion (fl uvial incision) where the upper (lst1) is directly overlain by the 2nd order depositional sequence of the abu roash formation, being truncated at the top by the sequence boundary (subaerial unconformity). the age of this lowstand system is early cenomanian. the lst1 deposits are limited by the fi rst sequence boundary (sb1), which delineates the end of the 1st sequence and the beginning of the second. 6.1.2. highstand systems tract 1 (hst1) based on the available data and their resulting interpretations lst and tst system tracts in the investigated well sections are entirely missing. the absence of these may be attributed to the erosion cycle, which is indicated by truncation at the top by the sequence boundary due to subaerial unconformity. this highstand system tract occurs in the lower part of the abu roash-g member, and represents the maximum phase of transgression after deposition of the bahariya formation (fig.32). the progradational hst1 sediments are characterized by an upward increase in gr and moderate to low resistivity. lithofacies of the hst1 sediments are entirely different from those of the lst1 sediments (fig. 31), and includes mainly shales and limestones. the limestone is laterally variable in thickness whereas the shale is concentrated mainly figure 29: showing the upper part of seismic line 5455 (west of the study area), (b): the interpreted seismic line 5455 displaying the main internal confi gurations which characterized the seismic facies of upper eocene to recent sequence (uers). geologia croatica 65/2geologia croatica 132 in the central part of the studied area. the total thickness of this high system tract reach a maximum (30 m) in the karmasw 1x well and is minimal (18 m) in the in karama-nw 5x well (fig. 31). 6.1.3. lowstand system tract (lst2) this systems tract represents the second studied low system. it consists of a small part of the abu roash-g member. the progradational lst2 sediments are characterized by low gr and relatively high resistivity. sediments of the lst2 are present all over the study area. the lithological composition of these deposits is mainly sandstone, mudstone and siltstone. the thickness of the lst2 sediments is quite small and uniform (about 10 m) (fig. 31). seismic facies analysis and gamma ray log confi rm that the sandstone sediments indicate that, the prevalent environments of depositions during deposition of this system tract were estuaries or shorelines. the sandstone units were most likely deposited as bayhead deltas, tidal channels and barrier beaches because they figure 30: system tracts, logs and depositional environment of turonian, campanian–maastrichtian, eocene and recent sequences of well aqsa-1x. mahsoub et al.: bioand sequence stratigraphy of upper cretaceous – palaeogene rocks, east bahariya concession, western desert, egypt geologia croatica 133 display the characteristic features of tidal environments with a high dynamic regime of and wave infl uence. 6.1.4. transgressive systems tract (tst1) the retrogradational deposits of tst1 are marked by high gr and represents the onset of transgression and sea-level rise (nummedal & swift, 1987). it overlies the transgressive surface (ts1), which tops the lowstand systems tract (lst1) (fig. 31). the tst1 sediments are composed of shale and limestone deposits in most of the area and mainly shale with a few limestone interbeds in the west of the study area. the maximum fl ooding surface (mfs1) separates the deposits of the retrograding interval of the tst1 below from the prograding deposits of the hst1 above (fig. 31). this surface, together with the tst1 sediments, is associated with high peaks in the gr logs (schaffer 1987; armentrout & clement, 1990). the thickness of this system tract shows an increase in the middle part of the investigated area and decrease laterally in both sides (fig. 31). interpretation of seismic facies and gamma ray log indicate that open marine conditions prevailing during the deposition of this system tract. 6.1.5. highstand systems tract 2 (hst2) this highstand system tract overlies the sediments of the transgressive systems tract tst1. lithofacies of the hst2 sediments are clearly different to those of the hst1 sediments. hst2 sediments contain more shale in comparison with the hst1 (fig. 31). the thickness of the hst2 sediments is quite variable. the maximum thickness (about 10 m) is detected at aqsa-1x and k-sw-1x wells, while the minimum thickness (4 m) in k-nw-1x well (fig. 31). from gr and lithology the prevailing environmental conditions during deposition of this system tract are deep marine conditions. 6.1.6. lowstand system tract 3 (lst3) the aggradational lst3 sediments have quite a similar well log response to those of the lst2 sediments (fig. 31). the lithology of these deposits is mainly pro-delta silty-mudstone, lower, middle and upper shoreface sandstone, distributary-mouth bar sandstone, and distributary-channel sandstone, silty-muddy interdistributary or coastal plain deposits. the thickness of these deposits is quite variable with maximum thickness (about 12 m) drilled in k sw-1x and k sw10x wells and minimum thickness (about 5 m) in k-nw-1x well. the log shape and the lithofacies characteristics of these sediments indicate that the lst3 sediments are deposited in similar conditions to those of the lst1. 6.1.7. transgressive system tract 2 (tst2) the retrogradational tst2 sediments have a quite different lithological composition and log response characteristics to those of the tst1. these sediments include the upper parts of the abu roach-g member, composed of shale, limestones and sandstone respectively. the upper boundary of the tst2 sediments is marked by an abrupt increase in the gr where the lower part shows low to moderate gr values. the increase of gr values in the upper part is due to an increase in the shale ratio within this system tract. the high shale content is attributed to the fact that, the early turonian started with the great transgresfigure 31: schematic diagram for w-e correlation of the system tracks in the abu roash-g member. geologia croatica 65/2geologia croatica 134 sion of the late cretaceous, which was recorded as the maximum fl ooding surface in the western desert (mfs2) (barakat, 1987). the thickness of these deposits is quite va riable with the maximum thickness of 60 m in well k-sw-1x. 6.2. systems tracts of turonian age 6.2.1. highstand systems tract 3 (hst3) this highstand system tract comprises the abu roash f, e and d members. with the advent of the turonian, the maximum fl ooding surface (mfs2) covered the northern part of the western desert (barakat, 1987). this system tract tops the transgressive systems tract tst2 and represents the upper part of the abu roash-g member. lithofacies of the hst3 sediments are similar to the hst1 sediments, composed mainly of shale and limestone (figs. 26 and 29) where the abu roash members e, f and g are the most prolifi c and outstanding source rocks in the western desert (lüning, 2004). 6.2.2. lowstand systems tract 4 (lst4) this lowstand systems tract is relatively thin representing part of the abu roash fm. in the turonian time (figs. 26 and 29). it overlies the high stand system tract (hst3). the intervals of lst4 are characterized by a relatively decrease in gamma ray values. this systems tract is part of the abu roash-c member, composed of shale, sandstone and limestone indicating a shallow shelf marine (sublittoral) environment (abdel khalek, 1989). 6.2.3. transgressive system tract 3 (tst3) tst3 sediments have quite similar lithological well log characteristics to those of tst1, which is exclusively composed of shale and limestone sediments. the upper boundary of the tst3 deposits is marked by moderate gr values. the second maximum fl ooding surface (mfs3) in turonian time in the western desert is encountered directly above this system tract (figs. 27 and 30). this system tract is apart of the abu roash-d member, which consists of limestone alternating with thin fl int bands refl ecting a shallow shelf marine environment (abdel khalek, 1989). 6.2.4. highstand systems tract 4 (hst4) this highstand systems tract occupies the top of the upper part of the abu roash fm. and consists mainly of shale, limestone and sandstone intercalations and its deposits display moderate to high gr values, because the main lithological component is shale. hst4 overlies the transgressive surface (mfs3), which tops the second transgressive systems tract of turonian age. the predominant environmental conditions of deposition were those of shallow marine shelf (abdel khalek, 1989). 6.3. system tracts of campanian–maastrichtian age 6.3.1. transgressive system tract 4 (tst4) this transgressive systems tract represents the beginning of the sequence boundary (ucs3), which covers the high stand system tract sediments (hst4) high stand system tract sediments whereas the lst was truncated during the coniacian and santonian at the top of khoman formation due to subaerial exposure represented by an unconformity. lithofacies of the lst4 sediments are composed of sediments of limestones intercalated with shale which denotes the lower part of the khoman fm. (figs. 27 and 30). the relatively deep sea conditions that prevailed by the offset of the early cenomanian persisted during the late cenomanian, turonian and attained their peak in the maastrichtian (barakat, 1987) as refl ected by the interpreted mfs4 surface. the tst4 is characterized by a strong increase in the gamma ray, which indicates an increase in sea level in the western desert (mfs4). 6.3.2. highstand systems tract 5 (hst5) this highstand systems tract represents the upper part of the khoman fm. and consists of open-marine white chalky limestone with chert bands. figure 32: formations, sequences, systems tracts and sea-level changes of the upper cretaceous-eocene age of the subsurface east bahariya succession. mahsoub et al.: bioand sequence stratigraphy of upper cretaceous – palaeogene rocks, east bahariya concession, western desert, egypt geologia croatica 135 it overlies the transgressive surface (mfs4), which tops the transgressive systems tract of campanian-maastrichtian age. data such as gr and fossil content indicate that the environmental conditions, which were prevailing during the deposition of the system tract, were indicative of a shallow inner shelf of marine environment. 6.4. systems tracts of eocene age 6.4.1. lowstand systems tract 5 (lst5) this lowstand system tract represents the lower part of the apollonia fm. (figs. 27 and 30) wich overlies the sequence boundary (sb3), where it is tops the high stand systems tract (hst5). the fossil content and available composite logs indicate that, this lowstand systems tract is composed of shallow marine limestone with numerous chert intervals. the cherty intervals of lst5 are characterized by a relative increase in gamma ray values. the high values are attributed to the concentration of organic matter within the chert beds. the lithological, foraminiferal data and characteristics of the seismic refl ectors of this sequence suggest that the depositional conditions in this systems tract range from outer shelf to inner shelf at the base of the eocene period. 6.4.2. transgressive systems tract 5 (tst5) this transgressive systems tract includes the middle part of the apollonia formation. it overlies lowstand systems tract sediments (lst5) of the eocene sequence (es). the mfs5 surface delineates the upper boundary of the retrograding sequence of the tst5 sediments. this surface is marked by the maximum gr response and the foraminiferal content (figs. 27 & 30). the mfs5 is overlain by the prograding sequence of hst6 sediments. this systems tract represents the maximum transgression recorded in the western desert area during the middlelate eocene. based on various types of available data the environmental conditions prevailing during the deposition of the system tract are outer shelf to inner shelf. 6.4.3. highstand systems tract 6 (hst6) this highstand systems tract consists of the upper part of the eocene sequence (es) and represents the upper part of the apollonia fm. it is characterized by the abrupt increase of the gamma ray values (figs. 28 & 31). this increase in gamma values is due to the high mud and silts fractions. highstand systems tract (hst6) overlies the maximum fl ooding surface mfs5, which tops the transgressive systems tract of eocene age, where it includes limestone with shale interbeds. limestone beds are rich in foraminifera which may indicate a deeper water habitat. 6.4.4. transgressive systems tract 6 (tst6) this transgressive systems tract includes the dabaa fm. it overlies the highstand systems tract (hst6) of the eocene sequence (es). transgressive system tract 6 (tst6) is characterized by an increase of gamma values with oscillation, but in the upper part gamma values suffer a moderate decrease compared to the lower part of this transgressive system tract (tst6). figure 33: illustrates the major structural trends in the western desert (after egpc, 1992). geologia croatica 65/2geologia croatica 136 the available data suggest that the lst was removed due to marine erosion (tawadros, 2001). the environmental conditions, which were predominant during the deposition of this transgressive systems tract, were marine outer shelf to deep marine environments. the aforementioned interpreted palaeo-environments of the study area exhibited echoes of the tectonic events affecting the southern margin of the tethys ocean. the study area, however, is located 80 km offshore southern tethys ocean in the abu gharadig basin, which is situated on the north african plate. this basin developed in conjunction with a complex series of e-w and northeast-southwest oriented normal and wrench faults (fig. 33) that formed during the late jurassic rifting and continued into, or were rejuvenated during the early cretaceous along the east mediterranean margin resulting in the oceanization of the eastern mediterranean basin. rifting resulted from the initiation of the closure of the tethys (guiraud, 1998). 7. summary and conclusions the calcareous nannofossils identifi ed belong to cc22, cc23, cc25 of the campanian – maastrichtian age and zones np12, np13 of early eocene age and np16 of middle eocene age and np18 and np19/20 of late eocene age. the ages of the different rock units were identifi ed by means of planktonic foraminifera as well as calcareous nannofossils and some hiatuses were detected within the studied wells as follows: 1. the latest cretaceous and the all of the palaeocene are probably missing in the whole area, resulting in a major unconformity which may suggest tectonic instability due to pulses of epeirogenic movements affecting the area. 2. the boundary between the apollonia fm. and the overlying dabaa fm. is represented by an unconformity with corresponding hiatuses of different time spans. while the latest eocene planktonic foraminifera such as cribrohantkenina, turborotalia cerroazulensis cocoaensis, turborotalia cerroazulensis cunialensis are absent, it is possible to identify the upper eocene by means of the index calcareous nannofossils. the apollonia fm. (campa nian-maastrichtian) rests unconformably on the khoman fm. (eocene) in the study wells. the upper part of the maastrichtian, as well as the entire palaeocene, the basal part of the eocene, and the upper part of the middle eocene are missing. the eocene/oligocene boundary could not be delineated due to the absence of nannofossil assemblages in the dabaa fm. 3. the upper cretaceous-palaeogene succession for the studied area allows classifi cation into fi ve major 2nd order depositional sequences, separated by four major depositional sequence boundaries (sb1, sb2, sb3 and sb4). the upper cretaceous–palaeogene succession in the east bahariya is divided into 17 systems tracts. the se systems tracts include: 7 system tracts of cenomanian age; 4 system tracts of turonian age, 2 system tracts of campanian – maastrichtian age and 4 system tracts of eocene age. acknowledgement *the authors wish to express their deep gratitude to the egyptian general petroleum corporation (egpc) for releasing the seismic sections, composite logs, e-logs, cuttings on which the biostratigraphy is based and for providing the offi cial permission to publish this work. the authors are deeply indebted to professor dr. christian betzler, geoscience department, hamburg university for his co-supervision through a channel system of the egyptian mission department. the mission department as well as ain shams university are greatly thanked. the authors thank professor dr.sc. bruno saftić, faculty of mining, geology and petroleum engineering, university of zagreb and the anonymous reviewer for reviewing the manuscript, their comments enhanced the quality of the manuscript. these thanks are extended to the associate editor, professor vlasta ćosović, particularly mme alisa martek and all the staff of geologia croatica for their efforts. references abdel aal & moustafa, a.r. (1988): structural framework in abu el gharadig basin, western desert, egypt.– in: egpc – 9th exploration conference, cairo, egypt, p. 16. abdel hamid, m.l. (1985): contribution to the geology of upper cretaceous with special emphasis on turonian-senonian sedimentation patterns and hydrocarbon potentials in the abu gharadig area, north western desert.– unpubl. ph.d. thesis, cairo university, 189 p. abdel khalek, m.l., el sharkawi, m.a., darwish, m., hagras, m. & sehim, a. (1989): structural history of abu roash district, western desert, egypt.– j. african earth sci., 9/3–4, 435–443. doi: 10.1016/0899-5362(89)90027-4 armentrout, j.m. & clement, j.f. (1990): biostratigraphic calibration of depositional cycles: a case study in high island-galveston-east breaks, offshore texas.– in: sequence stratigraphy as an exploration tool: concepts and practices in the gulf coast, sepm, gulf coast section – eleventh annual research conference – program with abstracts, 21–51. awad, g.m. (1984): habitat of oil in abu gharadig and fayium basins, western desert – egypt.– b. am. assoc. petrol. geol., 68, 564–513. barakat, m.g., darwish, m. & abdel hamid, m.l. (1984): detection and delineation of reservoir potential within abu roash formation, east abu gharadig area, north western desert, egypt.– in: abstracts of papers presented at the twenty-second annual meeting, geol. soc. of egypt, 1. barakat, m.g., darwish, m. & abdel hamid, m.l. (1987): hydrocarbon source rock evaluation of upper cretaceous “abu roash formation” east abu gharadig area; north western desert, egypt.– in: m.e.r.c., ain shams university, earth science – series -1, 120–150. bayoumi, a.i. & lotfy, h.i. (1989): modes of structural evolution of abu gharadig basin.– j. african earth sci., 9/2, 273–287. doi: 10.1016/0899-5362(89)90070-5 bayoumi, a.i., darwish, y.a. & lotfy, h.i. (1987): acoustic characteristics of the abu gharadig basin sediments.– j. african earth sci., 6/4, 399–405. doi: 10.1016/0899-5362(87) 90083-2 bayoumi, t. (1994): synsedimentary tectonics & the distribution of turonian sandstone reservoir, abu gharadig basin, western desert, egypt.– in: proceedings of the egpc 12th petroleum exploration & production conference, cairo, 1, 368–387. mahsoub et al.: bioand sequence stratigraphy of upper cretaceous – palaeogene rocks, east bahariya concession, western desert, egypt geologia croatica 137 bayoumi, t. (1996): the infl uence of interaction of depositional environment and synsedimentary tectonics on the development of some late cretaceous source rocks, abu gharadig bash, western desert, egypt.– in: proceedings of the egpc 13th petroleum exploration & production conference, cairo, 2, 475–496. berggren, w.a. & pearson, p.n. (2006): tropical to subtropical planktonic foraminiferal zonation of the eocene and the oligocene.– in: pearson, p.n. et al. (eds.): atlas of eocene planktonic foraminiferas. cushman found. spec. publ., 41, 29–40. blow, w.h. (1979): the cenozoic globigerinida: a study of the morphology, taxonomy, evolutionary relationships and the stratigraphical distribution of some globigerinida (mainly globigerinacea).– e. j. brill, leiden, 1413 p. bolli, h.m. (1957b): planktonic foraminifera from the oligocene – miocene cipero and lengua formations of trinidad, b.w.i.– in: loeblich, a.r. et al. (eds.): studies in foraminifera. u.s. natural museum bulletin, 215, 97–123. bronnimann, p. & stradner, h. (1960): die foraminiferen – und discoasteridenzonen von kuba und ihre interkontinentale correlation.– erdoel-z., 76, 364–369. bukry, d. & bramlette, m.n. (1970): coccolith age determinations, leg 3, deep sea drilling project.– in: deep sea drilling project, 3, 589–611. doi: 10.2973/dsdp.proc.3.118.1970 bukry, d. (1973a): coccolith stratigraphy, leg 10, deep sea drilling project.– in: deep sea drilling project, 10, 385–604. doi:10.2973/ dsdp.proc.10.117.1973 bukry, d. (1973b): low latitude coccolith biostratigraphic zonation.– in: deep sea drilling project, 15, 685–703. doi:10.2973/dsdp. proc.15.116.1973 caron, m. (1985): cretaceous planktic foraminifera.– in: bolli, h.m., saunders, j.b. & perch-nielsen, k. (eds.): plankton stratigraphy, cambridge university press, 17–86. caron, m., agnolo, s.d., accarie, h., barrera, e., kauffman, e.g., amédro, f. & robaszynski, f. (2006): highresolution stratigraphy of the cenomanian – turonian boundary in terval at pueblo (usa) and wadi bahloul (tunisia): stable isotope and bio-events correlation.– geobios, 39, 171–200. doi: 10.1016/ j.geobios.2004.11.004 catuneanu, o., khalifa, m.a. & wanas, h.a. (2006): sequence stratigraphy of the lower cenomanian bahariya formation, bahariya oasis, western desert, egypt.– sediment. geol., 190, 121–137. doi:10.1016/j.sedgeo.2006.05.010 darwish, m., abu khadrah, a.m., abdel hamid, m.l. & hamed, t.a. (1994): sedimentology, environment conditions and hydrocarbon habitat of the bahariya formation, central abu gharadig basin, western desert, egypt.– in: proc. of egpc 12th petrol. exploration & production conference, cairo, egypt, 1, 429–449. egpc (1992): western desert oil and gas fields (a comprehensive overview): egpc – 11th exploration conference.– egcp, cairo, egypt, 431 p. el bassyouny, a.a. (1970): geology of the area between gara el hamra of ball-qur lyons and ghard el moharrik, and its correlation with el harra area, bahariya oasis, egypt.– unpubl. msc thesis, cairo university, 180 p. emery, d. & myers, k.j. (1996): sequence stratigraphy.– blackwell, oxford, 297 p. doi:10.1002/9781444313710 ghanem, m.f. (1985): subsurface geology of the cretaceous sediments in the north western desert of egypt and its hydrocarbon potentialities.– unpubl. phd. thesis, faculty of science, cairo university, 131 p. guiraud, r. (1998): mesozoic rifting and basin inversion along the northern african tethyan margin: an overview.– in: macgregor, d.s., moody, r.t.j. & clark-lowes, d.d. (eds.): petroleum geology of north africa, london, geological society special publication, 132, 217–229. doi:10.1144/gsl.sp.1998.132. 01.13) harpe de la (1883): monographie der in ägypten und der libyschen wüste von kommenden nummuliten.– paleontographica, 30, 155–216. hay, w.w., mohler, h.p., roth, p.h., schmidt, r.r., & boudreaux, j.e. (1967): calcareous nannoplankton zonation of the cenozoic of the gulf coast and caribbean-antillean area and transoceanic correlation: gulf coast assoc.– geological society transactions, 17, 428–480. hay, w.w., mohler, h.p. & wade, m.e. (1966): calcareous nannofossils from nal' chik (northwest caucasus).– eclogae geol. helvet., 59, 379–399. ismail, m.m., el nozahy, f.a. & sadeek, k.n. (1989): a contribution to the geology of the bahariya oasis, western desert, eg ypt.– geological journal, 18/4, 379–391. doi:10.1007/ bf00772692 issawi, b., francis, m.h., youssef, e.a.a., & osman, r.a. (2009): the phanerozoic geology of egypt: a geodynamic approach: special publication, 81.– ministry of petroleum, cairo, 589 p. issawi, b., hinnawi, m., francis, m. & mazhar, a. (1999): the phanerozoic geology of egypt: a geodynamic approach.– geological survey of egypt, cairo, 462 p. smith joshua, b., lamanna mathew, c., helmut m. & lacovara kenneth, j. (2006): new information regarding the holotype of spinosaurus aegyptiacus stromer, 1915.– j. paleontol., 80/2, 400–406. lüning, s., adamson, k. & craig, j. (2003): frasnian organicrich shales in north africa: regional distribution and depositional mode.– in: arthur, t.j., macgregor, d.s. & cameron, n. (eds.): petroleum systems and emerging technologies in african exploration and production, special publication of the geological society, 207, 165–184. doi: 10.1144/ gsl.sp.2003.207.01.09 pasley, m.a., artigas, g., nassef, o. & comisky, j. (2009): depositional facies control on reservoir characteristics in the middle and lower abu roash „g” sandstones, western desert, egypt.– search and discovery article #50181, posted may 8, 2009. adapted from oral presentation at aapg international conference and exhibition, cape town, south africa, october 26–29, 2008. martini, e. (1971): standard tertiary and quaternary calcareous nannoplankton zonation.– in: farinacci, a. (ed.): proc. ii planktonic conference, roma, 2, 739–785. martini, e. (1976): cretaceous to recent calcareous nannoplankton from the central pacifi c ocean.– in: deep sea drilling project, 33, 383–423. norton, p. (1967): rock-stratigraphic nomenclatures of the western desert, egypt.– egyptian petroleum corporation, cairo, 557 p. nummedal, d. & swift, d.j.p. (1987): transgressive stratigraphy at sequence bounding unconformities.– in: nummedal et al. (eds.): sea level fluctuations and coastal evolution, sepm special publication, 41, 241–260. doi:10.2110/pec.87.41.0241 okada, h. & bukry, d. (1980): supplementary modifi cation and introduction of code numbers to the low latitude coccolith biostratigraphic zonation (bukry, 1973, 1975).– mar. micropaleontol., 5, 321–325. doi:10.1016/0377-8398(80)90016-x osman, r.a. (2003): contribution to the stratigraphy of el arag depression, north western desert, egypt.– sedimentology of egypt, 11, 157–167. perch-nielsen, k. (1972): remarks on late cretaceous to pleistocene coccoliths from the north atlantic.– in: deep sea drilling project, 12, 1003–1069. doi:10.2973/dsdp.proc.12.115.1972 perch-nielsen, k. (1985a): mesozoic calcareous nannofossils.– in: bolli, h.m., saunders, j.b. & perch-nielsen, k. (eds.): geologia croatica 65/2geologia croatica 138 plankton stratigraphy, cambridge univ. press, cambridge, 329–4. doi:10.2973/dsdp.proc.12.115.1972 said, r. (1962): the geology of egypt.– elsevier, amsterdam, 377 p. said, r. (1960): planktonic foraminifera from the thebes formation, luxor, egypt.– micropaleontology, 6, 277–286. doi:10.2307/ 1484234 schaffer, b.l. (1987): the potential of calcareous nannofossils for recognizing plio-pleistocene climatic cycles and sequence boundaries on the shelf.– in: eighth annual research conference, gulf coast section sepm foundation, 142–145. schlumberger (1984a): well evaluation conference, egypt.– schlumberger limited, new york, 250 p. sissingh, w. (1977): biostratigraphy of cretaceous calcareous nannoplankton.– geologie en mijnbouw, 56/1, 37–65. stromer, e. (1914): die togographi und geologie der strecke gharaq – baharije nebest ausfuhrungen ueber die geologische geschichte aegyptens.– abh. bayer, akad. wissensch., math.: naturw. kl., 11, 1–78. tawadros, e.e. (2001): geology of egypt and libya.– balkema, rotterdam, 468 p. toumarkine, m. & lutrbacher, h. (1985): paleocene and eocene planktic foraminifera.– in: bolli, h.m., saunders, j.b., & perch-nielsen, k. (eds.): plankton stratigraphy, cambridge univ. press, cambridge, 87–154. van wagoner, j.c., posamentier, h.w., mitchum, r.m., vail, p.r., sarg, j.f., loutit, t.s. & hardenbol, j. (1988): an overview of the fundamentals of sequence stratigraphy and key defi nitions.– in: wilgus, c.k. et al. (eds.): sea – level changes: an integrated approach, special publication of the society of eocene paleontology, mineral, 42, 39–45. younes, m.a. (2003): alamein basin hydrocarbon potentials, northern western desert, egypt (extended abstract).– in: aapg annual convention, may 11–14, 2003, salt lake city, utah, p. 6. manuscript received march 3, 2011 revised manuscript accepted march 04, 2012 available online june 29, 2012 04-fajkovic.indd 41 � ab stra ct soil samples from 31 locations in the una river spring catchment were subject to chemical extraction analyses. the data were presented as distribution maps of potentially toxic elements (al, cu, mn, pb and zn) in the surface soil of the area. to evaluate the vulnerability of the immediate spring zone of the karst catchment, the vulnerability map was derived from the application of the pi methodology proposed by the european cost action 620. the pi method used to produce the vulnerability map takes into account the protective cover (p) and the infi ltration conditions (i). it is based on the origin-pathway-target model. the π-factor (π = p ´ i) describes the vulnerability in the area, subdivided into 5 classes: π-factor in the range 0-1 implies an area of extreme vulnerability, while π-factor in the range 4-5 implies an area of very low vulnerability. the extraction procedure for the elements al, cu, mn, pb and zn, has been applied in order to determine the potential mobility and redistribution of elements that could infl uence the groundwater and affect its quality. the applied extraction was the second step of the sequential procedure proposed by tessier et al. (1979), i.e. extraction with 1 mol dm-3 ch3coona/ch3cooh buffer (ph 5). the results provide information on the potential mobility of the studied elements, indicating the possibility of their mobilization through changes in ph. lead shows the greatest amount of mobility, with a mean of 9% (max. 16%) extracted under an acidic condition. manganese follows with a mean of 5% (max. 11%) and zinc, copper and aluminium show less than 1% (mean) mobility. the vulnerability map of the karst area was produced in order to predict potential problem areas of karst aquifers. the una spring catchment area presents generally low to moderate vulnerability; 8% of the studied area can be considered as extremely vulnerable according to the pi-methodology. based on these data it was possible to delineate areas with a low protection cover i.e. combining the vulnerability map of the karst area with the distribution maps of potentially toxic elements, areas considered extremely vulnerable could be identifi ed. keywords: karst, vulnerability map, pi-method, soil, environmental geochemistry, una river vulnerability of the karst area related to potentially toxic elements � hana fajković1, ozren hasan2, slobodan miko2, mladen juračić1, saša mesić2 and esad prohić1 1department of geology, faculty of science, university of zagreb, horvatovac 95, 10000 zagreb, croatia; (hanaf@geol.pmf.hr) 2croatian geological survey, sachsova 2, 10000 zagreb, croatia; (slobodan.miko@hgi-cgs.hr) doi: 104154/gc.2011.04 geologia croatica 64/1 41–48 2 figs. 3 tabs. zagreb 2011 geologia croaticageologia croatica 1. introduction the study area lies in the una river valley, east of the small town of gračac, in the southern part of the lika region. it is a part of a catchment of the una spring and extends over 135 km2 (fig. 1). the una river spring surfaces near the village of suvaja, 399 m above sea level (bognar, 2005), and is protected as a hydrogeological heritage site of croatia. typical karst landforms are observed here, including dolines, sinkholes and karst springs (vauclusian type). sinkholes are covered, mostly by silt loam, and overgrown by vegetation. geologia croatica 64/1geologia croatica 42 the area is part of a high karst belt of the outer dinarides, the genesis of which is connected with the adriatic carbonate platform (adcp). the deposit can be very thick, in some areas surpassing 8000 m. the age of this carbonate succession ranges from middle permian, or even upper carboniferous to eocene (vlahović et al., 2005). the area of investigation is part of a large carbonate aquifer system which accounts for 88% of croatian ground water reserves, and is an important drinking water source (biondić, 2009). karst aquifers are exceptionally vulnerable to contamination due to their heterogeneity, which results in huge variations in permeability, and enables poorly fi ltered, concentrated recharge to take place (zwahlen, 2004). sin ce contaminants can easily reach the aquifer by bypassing fi ltra tion, it is important to know where such events might occur. predicting the path of possible pollutants in aquifers is more diffi cult in karst due to the fact that water often lacks a specifi c fl ow path. the objective of this paper was to evaluate the vulnerability of the karst catchment immediate to the una spring zone. to assess the vulnerability, a combined soil/geochemical approach with vulnerability mapping was applied. since the protection of groundwater is important not only from an ecological point of view, but also from an economic one, different approaches to ground water protection have been developed. comparative studies have shown that the application of various methods often leads to different results (nguyet & goldscheider, 2006; gogu et al., 2003). in order to develop an approach that considers the specifi cs of karst formations, a special group, cost action 620, was established. the group developed an approach to “vulnerability and risk mapping for the protection of carbonate (karst) aquifers” (zwahlen, 2004; nguyet & goldscheider, 2006), and proposed a new method of vulnerability mapping – the pi method – for mapping karst groundwater resources (zwahlen, 2003; goldscheider, 2005). this approach was used in this study. acidifi cation of the topsoil cover may cause the mobilization of certain potentially toxic elements that accumulate in the soil and could be transported into aquifers, thus affecting the water quality. therefore, topsoil can be considered a source of contamination, especially if possible changes in environmental conditions would lead to leaching of pollutants. with analysis of the soil for total elements and their mobile fraction, it is possible to distinguish between anthropogenic and geochemical sources of heavy elements (dube et al., 2001; filgueiras et al., 2002). 2. methods 2.1. laboratory analysis topsoil (0−2 cm) and subsoil (40−50 cm) samples were collected at 31 locations. some of the topsoil of each sample was used for granulometric analysis, which was performed on 29 samples, by wet sieving using astm standard stainless steel sieves. due to an insuffi cient amount of samples, granulometric analysis could not be performed for three samples. hydraulic conductivity for the 29 samples was defi ned by grain size composition of sediments using the hydraulic conductivity software, sizeperm. all samples were analyzed for total (hf-hclo4-hno3-hcl) and mobile fi gu re 1: geographic location of the studied area with the sampling sites. fajković et al.: vulnerability of the karst area related to potentially toxic elements geologia croatica 43 (ch3coona / ch3cooh, ph 5) contents of the elements of interest (al, cu, mn, pb and zn). analyses were carried out on the fraction <0.063 mm. inductively coupled plasma atomic emission spectrometry (icp-aes) was used for determination of the total content of elements in soils, for which samples were dissolved using 4-acid digestion (hf, hclo4, hcl, hno3), by standard procedure (miko et al., 2000). in order to determine the potential mobility and redistribution of the elements that could have an infl uence on the groundwater, the extraction procedure for elements al, cu, mn, pb, and zn was also applied. the sequential extraction procedure provides more information, than the analysis of the total heavy metal content of soil, i.e. it is possible to determine preferential binding sites for observed elements, to evaluate the potential mobility of metals in the environment and to differentiate the lithological from the anthropogenic contributions of elements (tessier et al., 1979; prohić & kniewald, 1987; aubert et al., 2004; kaasa lainen & yli-halla, 2003). for the purpose of the paper, only the second step of fi ve-step sequential extraction procedures based upon tessier et al. (1979) was carried out, i.e. extraction with 1 mol dm-3 ch3coona / ch3cooh buffer (ph 5), on the <0.063 mm size. the goal of this extraction was to observe the amount of the mobile fraction under specifi c ph conditions (5). 2.2. intrinsic vulnerability mapping the data for the vulnerability map were compiled from the digital topographic data (scale 1:25000), which included land-use data, sinkhole distribution data, a digital elevation model (dem), soil map data, geological and hydrogeological digital maps, and a database of potential pollution sources (road infrastructure, settlements). the vulnerability map was the fi nal result of different analyses and a few intermediate steps, which are briefl y described in this paper. the vulnerability map is coloured according to π-factor, which is expressed by π = p ´ i (table 1). the pi method takes into account the protective cover (p) and the infi ltration conditions (i). its goal is to describe how vulnerable the groundwater is. extreme vulnerability is presented as a red colour, while very low vulnerability is presented in a blue colour (tab. 1). in order to be able to compute the p factor (protective cover), the following information about the protective function was used: topsoil and subsoil thickness, precipitation regime, grain size, lithology, fi ssuring and karstifi cation. the p-factor ranges from 1 to 5, with 1 presenting a very low protective function. the i-factor gives an insight into infi ltration conditions and the degree to which the protective cover is by-passed as a result of lateral surface and subsurface fl ows. in order to compute the i-factor, information about the hydraulic conductivity, depth to low permeability layers, slope gradient and vegetation was used. the i factor ranges between 0.0 and 1.0, with 0 being the most permeable (goldscheider et al., 2000). some of the information on vegetation and slope gradient were directly taken from digital data. the vulnerability map was derived from application of the pi methodology proposed by the european cost action 620; detailed information and a description of these methods can be found in zwahlen (2004). according to this methodology, intrinsic vulnerability takes into account the geological, hydrological and hydrogeological characteristics of an area, but it is independent of the nature of the contaminants and the contamination scenario. it is based on the origin-pathway-target model, and as fi nal result, areas considered extremely vulnerable could be highlighted. the origin is the term used to describe the location of a potential contaminant release. the pathway includes the passage of potential contaminants, from its origin to the target (receptor). the target may be the groundwater surface in the aquifer (goldscheider et al., 2000). 3. results analyses for the total and mobile content of observed elements, (al, pb, cu, mn and zn) are presented in table 2. the analyses were used to display the percentage of mobile content for all topsoil samples. results of soil texture classifi cation, based on a granulometric analysis are also presented in table 2. information about the hydraulic conductivity was needed to compute the i-factor of the pi method. this was calculated from granulometric analysis, with the software easyperm, and for all samples,values fall in the range of 10-8 cm/s to 10-9 cm/s. from the geochemical analysis, colour scale maps were generated for the mobile fraction content of the topsoil cover in relation to the deeper layer (figs. 2a–e). maps indicate which part of the examined area is mostly exposed to migration of the mobile fraction of elements. lead shows the highest probability of mobility, with a mean of 9% (max. 16%) extracted under acidic conditions. manganese follows with a mean of 5% (max. 11%), and zinc, copper and aluminium table 1: common legend for the vulnerability map, the p and the i map (goldscheider, 2005). vulnerability map vulnerability of groundwater p – map protective function of overlying layers i – map degree of bypassing description π – factor description p – factor description i – factor extreme 0 – 1 very low 1 extreme 0.0–0.2 high >1 – 2 low 2 high 0.4 moderate >2 – 3 moderate 3 moderate 0.6 low >3 – 4 high 4 low 0.8 very low >4 – 5 extreme 5 very low 1. 0 geologia croatica 64/1geologia croatica 44 fi gu re 2: the maps of the content of mobile fraction of the topsoil cover in relation to the deeper layer for aluminium (a), copper (b), manganese (c), lead (d), zinc (e) and the pi vulnerability map (f ). fajković et al.: vulnerability of the karst area related to potentially toxic elements geologia croatica 45 table 2: mobile portion rate as a proportion of mobile (1 mol dm–3 ch3coona) (ph 5/ch3cooh) and total (hf-hcl-hno3-hclo4) element concentration in the soil. al (mob) al (tot) % al mob pb (mob) pb (tot) %pb mob cu (mob) cu (tot) % cu mob mn (mob) mn (tot) % mn mob zn (mob) zn (tot) % zn mob texture classifi cation mg/kg mg/kg % mg/kg mg/kg % mg/kg mg/kg % mg/kg mg/kg % mg/kg mg/kg % u 01a 1018 73100 1.39 5.935 37.9 15.66 0.26 26.6 0.98 13 358 3.63 1.7 102 1.67 silt loam u 01b   85700     31.2     37     168     88     u 02a 1043 64600 1.61 3.336 30.2 11.05 0.16 23.6 0.68 29 617 4.7 0.3 97 0.31 silt loam u 02b   76700     24.4     27     845     108     u 03a 41 74000 0.06 1.389 38.5 3.61 0.19 27.3 0.7 55 1087 5.06 1.2 104 1.15 silt loam u 03b   84200     34.9     28.9     969     104     u 04a 309 79300 0.39 2.744 39.6 6.93 0.12 30.3 0.4 43 999 4.3 1.1 120 0.92 silt clay loam u 04b   83400     34.1     29.4     993     116     u 05a 101 75800 0.13 3.504 33.2 10.55 0.24 26.4 0.91 29 545 5.32 0.6 106 0.57 silt loam u 05b   n.a.     n.a.     n.a.     n.a.     n.a.     u 06a 121 56100 0.22 4.994 47.3 10.56 0.23 24.4 0.94 78 668 11.68 4 171 2.34 silt loam u 06b   84000     35.5     30.6     990     206     u 07a 1464 80400 1.82 3.467 41.8 8.29 0.43 29.4 1.46 40 1309 3.06 1.3 149 0.87 silt loam u 07b   82700     40     32.7     1119     158     u 08a 503 834 00 0.6 7.33 62.3 11.77 0.19 25.3 0.75 56 1222 4.58 1.9 144 1.32 silt loam u 08b   85600     49.9     26     1262     128     u 09a 624 76400 0.82 4.674 41.2 11.34 0.23 19.9 1.16 30 828 3.62 1 108 0.93 silt loam u 09b   81000     39     21     907     95     u 10a 896 83100 1.08 6.576 84.2 7.81 0.33 32.8 1.01 59 1903 3.1 1.2 175 0.69 silt clay loam u 10b   87800     84.2     30.9     2021     169     u 11a 595 77800 0.76 5.857 46.3 12.65 0.18 32.3 0.56 44 774 5.68 1.9 140 1.36 silt loam u 11b   85200     40.1     31.2     931     119     u 12a 152 73800 0.21 2.855 37.8 7.55 0.12 27.7 0.43 68 1063 6.4 1.9 116 1.64 silt loam u 12b   78000     35     29.1     1153     112     u 13a 157 72900 0.22 3.442 66.1 5.21 0.12 39.7 0.3 69 1352 5.1 3.1 145 2.14 silt loam u 13b   n.a.     n.a.     n.a.     n.a.     n.a.     u 14a 704 70900 0.99 4.942 33 14.98 0.18 25.9 0.69 31 599 5.18 1.3 112 1.16 silt loam u 14b   84100     29.2     31.7     661     119     u 15a 1672 71700 2.33 5.012 42.4 11.82 0.46 23.8 1.93 56 718 7.8 2.9 130 2.23 clay loam u 15b   83100     37.4     24.1     613     123     u 16a 51 72000 0.07 3.583 41.7 8.59 0.31 29.6 1.05 86 976 8.81 1.7 108 1.57   u 16b   82600     33.4     27.2     837     95     u 17a 719 68100 1.06 4.422 38.7 11.43 0.1 24.7 0.4 29 759 3.82 1.1 105 1.05 loam u 17b   77900     30.9     21.8     776     95     u 18a 124 70600 0.18 2.751 28.6 9.62 0.72 29.8 2.42 33 394 8.38 0.5 94 0.53 silt clay loam u 18b   n.a.     n.a.     n.a.     n.a.     n.a.     u 19a 183 70600 0.26 4.781 48.3 9.9 0.14 19 0.74 35 665 5.26 0.3 106 0.28 silt loam u 19b   76300     46.6     19.1     783     114     u 20a 263 65000 0.4 3.087 29.7 10.39 0.12 15.1 0.79 20 403 4.96 0.6 82 0.73 clay loam u 20b   67500     28.7     13.2     356     83     u 22a 408 66100 0.62 6.149 38.3 16.05 0.19 15.2 1.25 31 594 5.22 0.5 75 0.67   u 22b   67400     41.2     14.6     785     76     u 23a 123 79400 0.15 2.418 39.7 6.09 0.24 29.8 0.81 39 703 5.55 0.7 112 0.63 silt clay loam u 23b   77000     40.4     26.9     818     103     u 24a 512 68300 0.75 4.285 35.7 12 0.33 21.2 1.56 51 608 8.39 0.8 99 0.81 silt clay loam u 24b   75600     31.5     21     712     104     geologia croatica 64/1geologia croatica 46 table 3: the highest measured content of the mobile fraction for observed area and the maximum allowed concentration of elements of interest in drinking water. al cu pb mn zn maximum allowed concentration of elements in drinking water (mg/l); n.n. 56/08 0.2 1 0.01 0.05 3 the highest measured concentration of mobile fraction (mg/l) 2330 1930 16050 11680 2340 table 2: mobile portion rate as a proportion of mobile (1 mol dm–3 ch3coona) (ph 5/ch3cooh) and total (hf-hcl-hno3-hclo4) element concentration in the soil. al (mob) al (tot) % al mob pb (mob) pb (tot) %pb mob cu (mob) cu (tot) % cu mob mn (mob) mn (tot) % mn mob zn (mob) zn (tot) % zn mob texture classifi cation mg/kg mg/kg % mg/kg mg/kg % mg/kg mg/kg % mg/kg mg/kg % mg/kg mg/kg % u 25a 224 76400 0.29 2.164 31.8 6.81 0.3 25.7 1.17 18 515 3.5 0.4 97 0.41 silt clay loam u 25b   79500     32.9     24.3     653     100     u 26a 237 86500 0.27 2.301 39.3 5.85 0.19 31.1 0.61 53 941 5.63 0.7 121 0.58 silt clay loam u 26b   85200     38.9     31.1     897     120     u 27a 229 75800 0.3 1.994 36.9 5.4 0.12 28.6 0.42 25 936 2.67 0.6 108 0.56 silt clay loam u 27b   73500     31.4     23.6     939     94     u 28a 216 85800 0.25 1.748 37 4.72 0.16 38 0.42 33 957 3.45 0.2 126 0.16 silt clay loam u 28b   n.a.     n.a.     n.a.     n.a.     n.a.     u 29a 80 82700 0.1 4.939 79.7 6.2 0.18 36.8 0.49 94 1357 6.93 1.3 179 0.73 silt loam u 29b   92100     37.4     40.8     1010     133     u 30a 106 87500 0.12 4.063 79.9 5.09 0.08 31.4 0.25 83 1313 6.32 0.6 161 0.37 silt loam u 30b   n.a.     n.a.     n.a.     n.a.     n.a.     u 31a 299 87800 0.34 6.307 73 8.64 0.2 33.9 0.59 46 1288 3.57 0.6 166 0.36 silt clay loam u 31b   84700     60.1     29.2     1296     141     u 32a 205 79800 0.26 1.962 35.8 5.48 0.16 27.4 0.58 18 1010 1.78 0.2 98 0.2 silt loam u 32b   n.a.     n.a.     n.a.     n.a.     n.a.     show less than 1% (mean) of mobile content. it is important to note that the same colour on these maps, for different elements, do not hold the same value. the colour scale was made separately for each map according to its minimum and maximum values. for instance, orange colour on the map represents 1.46% mobile content for aluminium, but 11.68% for manganese. the vulnerability map of the karst area was compiled by combining a digital topographic map (scale 1:25000) and values of p and i factor (fig. 2f). it was made to predict potential problem zones where the karst aquifer might be easily contaminated. the una spring catchment area has low to moderate vulnerability in most parts, but 8% of the studied area could be considered as extremely vulnerable according to the pi-methodology. the steps preceding the creation of the vulnerability map are not displayed here, but details needed to produce a vulnerability map can be found in the cost action 620 report (zwahlen, 2004). 4. discussion and conclusion two types of maps, the pi-map (or vulnerability map), and maps of the mobile fraction content of the topsoil cover in relation to the deeper layer, were combined in order to assess the potential hazard to groundwater. maps of the mobile fraction content for observed elements (al, mn, pb, cu, zn) provide information about their potential mobility, indicating the possibility of mobilization through changes in ph. on these maps, the area with the highest content of mobile fraction is shown in red. it is important to be aware of wellconnected environmental processes, in which acidifi cation of the terrain as a result of climate change or anthropogenic impact may lead to increased levels of metals in the aquifer (dube et al., 2001). extraction analysis, used for making these maps, is a common procedure when the goal is to indicate potential risk of toxic species entering the groundwater (rao et al., 2008). depending on the type of soil, and the ph used in the extraction procedure, heavy metals can be retained in a soil sample, but some amount can be observed as mobile content (lafuente et al., 2008; rao et al., 2008; filgueiras et al., 2002). not all the mobile content will dissolve in water. heavy metals may interact, chemically or physically, with the natural compounds found in the water and, in general, may react with particular species, change oxidation states and precipitate out (dube et al., 2001). however, one part will dissolve in the water, while the other could be found in colloidal fractions or associated with colloids (jensen et al., 1999; christensen et al., 2001). in the same aquatic environmental condition, dissolution of mobile elements will increase the higher the content of mobile elements. further, due to features of fajković et al.: vulnerability of the karst area related to potentially toxic elements geologia croatica 47 ka rst hydrogeology, contaminants can quickly appear in areas distant from the source, and affect the quality of the aquifer. if the protective cover is by-passed due to karst features, potential pollution can reach the aquifer in a short time. in order to prevent such scenarios, it is important to know which area is the most vulnerable. the pi-map provides such information. the red-coloured areas of the pi-map represent the zones with the lowest protection function of the aquifer. according to the pi-methodology, as shown in results, 8% of the studied area can be considered extremely vulnerable (fig. 2f). by combining the aforementioned maps, it is possible to discuss potential scenarios that could lead to contamination of groundwater, and use the composite map as a decision-making tool in a sanitation or pollution-prevention process. the worst-case scenario would be if the red areas of both types of maps overlap. that would imply the absence of a suitable effi cient barrier between the possible contaminant and the groundwater, and should lead to protective measures. luckily, in the investigated area presented in this paper, red zones from the maps do not entirely coincide. as the red zones do not overlap, the question arises of which type of map should have preference as decision-making tool, (the pi map, or the mobile content map). each situation should be considered separately, depending on the observed conditions. by considering both variables, it is possible to identify areas that must be prioritized in terms of protection, or monitoring and restriction of use (nobre et al., 2007). in such assessment, the areas of the highest proportion of mobile elements and those of extreme vulnerability are to be considered as important guidelines. for instance, if a red area of the pi-map (extremely vulnerable) overlapped with a low proportion of mobile elements (blue), then that area would have a lower priority than a yellow area of the pi-map (medium vulnerability) overlapping with an extremely high proportion of mobile elements (red). such conclusions could be a helpful guide for investors, e.g. a water bottling branch. the main information that can be obtained from the maps in the paper is that the groundwater would not be seriously affected if environmental conditions changed to ph 5. acknowledgments this work was supported by the croatian geological survey as a part of the research project and in cooperation with ina d.d. the authors would also like to thank ina d.d. for data used in this study. we are thankful to stephanie kramer for her suggestions and help with the paper. references aubert, d., probst, a. & stille, p. (2004): distribution and origin of major and trace elements (particularly ree, u and th) into labile and residual phases in an acid soil profi le (vosges mountains, france).− applied geochemistry, 19, 899–916. biondić, d. (2009): strategija upravljanja vodama.− hrvatske vode, zagreb, 180 p. bognar, a. (2005): the upper part of the una river valley between martin brod and pritoka – geomorphological characteristics.− hrvatski geografski glasnik, 67/2, 21−38. christensen, t.h., kjeldsen, p., bjerg, p.l., jensen, d.l., christensen, j.b., baun, a., albrechtsen, h. & heron, g. (2001): biogeochemistry of landfi ll leachate plumes.− applied geochemistry, 16, 659−718. dube, a., zbytniewski, r., kowalkowski, t., cukrowska, e. & buszewski, b. (2001): adsorption and migration of heavy metals in soil.− polish journal of environmental studies, 10, 1−10. filgueiras, a. v., lavilla, i. & bendicho, c. (2002): chemical sequential extraction for metal partitioning in environmental solid samples.− j. environ. monit., 4, 823−857. gladney, e.s. & burns, c.e. (1984): compilation of elemental concentration data for the usgs geochemical exploration reference samples gsr-1 to gsr6.− geostandard newsletters, 8/2, 119−154. gogu, r.c., hallet, v. & dassargues, a. (2003): comparison of aquifer vulnerability assessment techniques. application to the neblon river basin (belgium).− environ. geol., 44/8, 881–892. goldscheider, n. (2005): karst groundwater vulnerability mapping: application of a new method in the swabian alb, germany.− hydrogeology journal, 4, 555−565. goldscheider, n., klute, m., sturm, s. & hötzl, h. (2000): the pi method − a gis-based approach to mapping groundwater vulnerability with special consideration of karst aquifers.− z. angew. geol., 46/3, 157−166. jensen, d.l., ledin, a. & christensen, t.h. (1999): speciation of heavy metals in landfi ll-leachate polluted groundwater.− water research, 33, 2642−2650. kaasalainen, m. & yli-halla, m. (2003): use of sequential extraction to assess metal partitioning in soils.− environmental pollution, 126, 225–233. kashem, m.a., singh, b.r., kondo, t., huq, i.s.m. & kawai, s. (2007): comparison of extractability of cd, cu, pb and zn with sequential extraction in contaminated and non-contaminated soils.− int. j. environ. sci. tech., 4, 169−176. kerndorff, h. & schnitzer, m. (1980): sorption of metals on humic acid.− geochim. cosmochim. acta, 44, 1701−1708. lafuente, a.l., gonzález, c., quintana, j.r., vázquez, a. & romero, a. (2008): mobility of heavy metals in poorly developed carbonate soils in the mediterranean region.− geoderma, 145, 238−244. miko, s., peh, z., bukovec, d., prohić, e. & kastmüller, z. (2000): geochemical baseline mapping and lead pollution assessment of soils on the karst in western croatia.− nat. croat., 9/1, 41–59. maiz, i., esnaola, m.n. & millfin, e. (1997): evaluation of heavy metal availability in contaminated soils by a short sequential extraction procedure.− science of the total environment, 206, 107−115. de matos, a.t., fontes, m.p.f., da costa, l.m. & martinez, m.a. (2001): mobility of heavy metals as related to soil chemical and mineralogical characteristics of brazilian soils.− environmental pollution, 111, 429−435. nguyet, v.t.m. & goldscheider, n. (2006): a simplifi ed methodology for mapping groundwater vulnerability and contamination risk, and its fi rst application in a tropical karst area, vietnam.− hydrogeol. j., 14/8, 1666–1675. nobre, r.c.m., rotunno, f.o.c., mansur, w.j., nobre, m.m.m. & cosenza, c.a.n. (2007): groundwater vulnerability and risk mapping using gis, modeling and a fuzzy logic tool.− journal of contaminant hydrology, 94, 277−292. olsson, t. & tyler, g. (2001): concentrations of 60 elements in the soil solution as related to the soil acidity.− european journal of soil science, 52, 151−165. geologia croatica 64/1geologia croatica 48 prohić, e. & kniewald, g. (1987): heavy metal distribution in recent sediments of the krka river estuary-an example of sequential extraction analysis.− mar. chem., 32, 279−297. pueyo, m., mateu, j., rigol, a., vidal, m., lopez-sanchez, j.f. & rauret, g. (2008): use of the modifi ed bcr threestep sequential extraction procedure for the study of trace element dynamics in contaminated soils.− environmental pollution, 152, 330−341. rao, c.r.m., sahuquillo, a. & sanchez, j.f.l. (2008): a review of the different methods applied in environmental geochemistry for single and sequential extraction of trace elements in soils and related materials.− water air soil pollut., 189, 291–333. tessier, a., campbell, p.g.c. & bisson, m. (1979): sequential extraction procedure for the speciation of particular trace metals.− analytical chemistry, 51, 844−851. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.− palaeogeography, palaeoclimatology, palaeoecology, 222, 333−360. zhang, c. (2005): using multivariate analyses and gis to identify pollutants and their spatial patterns in urban soils in galway, ireland.− environmental pollution, 142, 501−511. zwahlen, f. (2004): vulnerability and risk mapping for the protection of carbonate (karst) aquifers. final report − action cost 620 − european commission, brüssel, luxemburg.− directorate-general for research, 297 p. manuscript received december 11, 2009 revised manuscript accepted december 15, 2010 available online february 22, 2011 1. introduction the eastern part of the drava depression in the north and part of the slavonia-srijem depression in the south, divided by the central –akovo-vinkovci plateau together with the vukovar plateau, are deeply subsided structural depressions which were formed along regional faults characterised by the horizontal displacement and movement of coherent tectonic blocks to the northeast, which influenced the formation of large extension zones. the plateaux have the morphology and structure quaternary deposits as the hydrogeological system of eastern slavonia andrea ba»ani1, marko ©parica 2 and josipa veli∆ 1 of complex horst structures, that are separated from the neighbouring depressions by systems of deep faults (figs. 1 and 2). with respect to the surface water and groundwater, two drainage areas are defined the drava drainage area in the north and the sava drainage basin in the south. the surface and subsurface watersheds between these two areas are located on the –akovovinkovci and the vukovar plateaux. for construction of the geological map shown in fig. 1, the following sheets of the basic geological map of sfrj scale 1:100,000 were used: donji miholjac (he∆imovi∆, 1985), naπice (korolija & jami»i∆, 1989a), osijek (maga©, 1987a), odæaci (trifunovi∆ & stojadinovi∆, 1985), slavonski brod (©parica, 1987), vinkovci (brki∆ et al., 1989), baëka palanka (»i»uli∆-trifunovi∆ & geol. croat. 52/2 141 152 7 figs. zagreb 1999 key words: hydrogeological system, watershed, lithological continuity, fault zones, transmissivity, plateau, eastern slavonia, croatia. kljuëne rijeëi: hidrogeoloπki sustav, razvodnica, litoloπki kontinuitet, rasjedne zone, transmisivnost, ravnjak, istoëna slavonija, hrvatska. 1 faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, hr-10000 zagreb, croatia. 1 institute of geology, sachsova 2, hr-10000 zagreb, croatia. abstract the area of eastern slavonia, situated between the drava and sava rivers, comprises three geotectonic units: the eastern part of the drava depression in the north, part of the slavonia-srijem depression in the south and the central –akovo-vinkovci plateau together with the vukovar plateau. these units are separated by deep faults that reach the base of the tertiary sediments. the first 200 m of quaternary deposits are saturated with fresh water. the aim of this study was to find out whether the faults form impermeable boundaries separating the waterbearing deposits into independent hydraulic systems, or if a singular hydraulic entity exists. results of the analysis indicate that lithological continuity of the aquifers exists along the fault zones on the margins of the –akovo-vinkovci and the vukovar plateaux, which means that there is no impermeable hydraulic boundary on the watershed between the sava and drava river valley. the part of eastern slavonia between the sava and drava rivers is one hydraulic system consisting of zones with different transmissivity values. in the zones of reduced transmissivity, the hydraulic connections are weakened, but not broken. such zones exist not only along the fault zones of the –akovo-vinkovci plateau and the vukovar plateau, but also within the sava and drava depressions. the terrain morphology influenced formation of both the surface and the underground watershed, parallel to the extension of the –akovo-vinkovci and vukovar plateau. therefore, within this single hydraulic entity, when the drawdown reaches the watershed due to excessive pumping, the watershed will be displaced from its natural position. saæetak u prostoru istoëne slavonije, izmeu save i drave nalaze se tri geotektonske jedinice i to na sjeveru istoëni dio dravske potoline, na jugu dio slavonsko-srijemske potoline, a izmeu njih –akovaëkovinkovaëki i vukovarski ravnjak. ravnjaci su u morfoloπkom i strukturno-tektonskom pogledu sloæene timorske strukture, koje su od susjednih potolina odvojene sistemima dubokih rasjeda koji zadiru u podlogu tercijarnih sedimenata. zbog morfologije terena se duæ pruæanja –akovaëko-vinkovaëkog i vukovarskog ravnjaka proteæe povrπinska i podzemna razvodnica koja istraæivani prostor dijeli u dva sliva: dravski na sjeveru i savski na jugu. cilj ovog rada bio je istraæiti da li rasjedne zone izmeu ravnjaka i potolina predstavljaju nepropusnu granicu koja naslage dijeli u dva odvojena hidrauliëka sustava ili one ëine jednu hidrauliëku cjelinu. analizom su obuhvaêene kvartarne naslage koje sadræe vodu pogodnu za vodoopskrbu, a koje zalijeæu do dubine od 200 m. rezultati analize pokazali su da litoloπki kontinuitet vodonosnih slojeva duæ rasjednih zona –akovaëko-vinkovaëkog i vukovarskog ravnjaka nije prekinut, te da na razvodnici savskog i dravskog sliva ne postoji nepropusna hidrauliëka granica. prostor istoëne slavonije izmeu drave i save smatra se jednim hidrauliëkim sustavom unutar kojeg postoje zone s razliëitim vrijednostima transmisivnosti. duæ zona smanjene transmisivnosti hidrauliëke veze su oslabljene, ali nisu prekinute. takve zone nisu prisutne samo duæ rasjednih zona –akovaëko-vinkovaëkog i vukovarskog ravnjaka nego i unutar pojedinih depresija. u sluëaju da sniæenje uzrokovano crpljenjem dosegne razvodnicu zapoëinje dotok vode iz podruëja s druge strane razvodnice, tj. razvodnica se premijeπta u odnosu na prirodni poloæaj udaljavajuêi se od mjesta crpljenja. 142 geologia croatica 52/2 fig. 1 geological map. • .:!t-.' .--------.. -..... --~ / --__ ~m f ' . ',­-.• • •• -------~ " .-<>. • galovi∆, 1985a), brëko (buzaljko et al., 1987) and bijeljina (vrhov»i∆ et al., 1986). the structures and other tectonic data were compiled after the works of hernitz (1983) and prelogovi∆ et al. (1995). the aim of the study was to determine whether the fault zones between the plateaux and depressions constitute an impermeable zone that separates the sava and drava drainage area into two hydraulic systems, or whether a singular hydraulic entity exists. the shallowest 200 metres of sediments favourable for water-supply were explored. 2. data-sets and methods the work is largely based on the analysis of geological and hydrogeological data that were published in scientific and professional papers and books, as well as on the numerous reports in the archives of several companies and scientific institutions. these data were interpreted together with fieldwork and laboratory investigations of the sediments drilled in 518 wells. the most important data obtained from the wells were the total depth, depth-intervals of permeable layers and the ratio of the thickness of permeable and impermeable layers. the following hydrogeological parameters of the wells were calculated: average hydraulic conductivity, transmissivity, storage coefficient and leakage coefficient. the drilling data and the well-logs (primarily the e-logs and the radioactive logs) were correlated in a north south direction in order to depict the lateral relationships of the plateau sediments to the depressions. due to the fact that there is a limited number of wells in the marginal zones, the data set was complemented with interpretation of geoelectric measurements. the results obtained by utilisation of the mathematical models that covered the marginal zone were also taken into account. 3. results the results of comprehensive analyses of all the data that were at our disposal, originating from the sources mentioned above, can be grouped in accordance to the scientific disciplines geological (stratigraphic, tectonic and palaeogeographic), hydrogeological and hydraulical data. their synthesis solved the problem of the continuity of the aquifer layers in the studied area of a relatively complex geological structure. 3.1. quaternary geological evolution in view of the water-supply possibilities, the most interesting sediments were deposited during the middle and upper pleistocene. this is the reason why this overview of the geological history only covers the quaternary period. 143baëani, ©parica & veliê: quaternary deposits as the hydrogeological system of eastern slavonia fig. 2 geological cross-sections a-a’ and b-b’. 144 geologia croatica 52/2 in northern croatia, there is a continuation of like depositional environments between the pliocene (uppermost tertiary) and the quaternary, the pliocene being characterised by large aquatic areas with sediments of significant thickness, especially in the subsiding depressions. it also means that the pliocene p l e i stocene boundary has not yet been defined with confidence. subsequent to the strong tectonic events between the pliocene and quaternary, and to the breakthrough of the danube in the –erdap canyon, the lakes and swamps gradually dried up, followed by formation of the drainage pattern. there are only scarce data on the lower pleistocene of the explored area. there are no outcrops. the age was proved by fossil findings in a small number of wells in otok (soka», 1976), vinkovci (soka» & harten, 1978), trpinja (maga©, 1987b; muti∆, 1989), in vladislavci and osijek (maga©, 1987b), in erdut and dalj (soka» et al., 1982) and also in valpovo (korolija & jami»i∆, 1989b). the lower pleistocene sediments are mostly clay, silt and some sand. due to the fact that their contact with the pliocene is not defined, it is also impossible to tell the thickness of these sediments. the lower pleistoc e ne middle pleistocene boundary is defined on the conditional e-log marker q’ (fig. 2). above the q’ marker horizon, there is a domination of permeable sediments, sand with some gravel, while underlying sediments are of low permeability silt and clay (urumovi∆ et al., 1976, 1978). in the uplifts of the –akovovinkovci and the vukovar plateaux, the q’ horizon lies at depth of approximately 150 m, while in depressions it is mostly below 200 m, sometimes even 300 m (hernitz, 1983). the middle pleistocene sediments are also buried, apart from a small outcrop on the northern slope foothills of the erdut hill (fig. 1, trifunovi∆, 1985). nevertheless, these sediments are well studied due to the large number of water exploration wells, some of them drawn on the geologic cross-sections (fig. 2). it was during the middle pleistocene that the main mass of the hydrogeologically interesting permeable sediments were deposited. the eastern slavonia area was then covered by shallow lakes and swamps and the neighbouring bosnian and slavonian mountains were land areas exposed to strong denudation. the transport and deposition of clastic material, respectfully several cycles of redeposition, was also very dependent on the palaeoclimate. the most significant palaeoclimate char acteristic was the alternation of the warm and humid periods with cold and very dry periods. during the warmer interglacial periods, the high waters of surface streams transported a lot of the coarse-grained clastic material and deposited it in the swamps and lakes. at the same time, the level of stagnant waters rose, so the swamps and lakes grew and covered a bigger area, until eventually they became interconnected. in contrast, the glacial periods are characterised by a draw-back of the surface streams into their river-beds, a reduction of their transport capabilities, and by the shallowing of the depositional area. the wind forces took the dominant role in the transport of sedimentary material, while silt and clay were deposited in the remaining lakes and swamps. in some places, the aquatic environments totally dried up which enabled the formation of palaeosols. the related palaeogeomorphological circumstances are explored, documented and explained in the works of veli∆ & durn (1993) and veli∆ & safti∆ (1996). the aforementioned depositional environments are confirmed by fossil findings. the ostracods significant for the shallow stagnant waters were determined by soka» (1976), soka» & harten (1978), soka» et al. (1982) and urumovi∆ & soka» (1974). the characteristic malacological community of the swamp biotope was interpreted by trifunovi∆ (1985), and the important biotope for the fluvial-paludal environment was discovered by »i»uli∆-trifunovi∆ & galovi∆ (1985b). terrestrial species were determined by poje et al. (1995) and by malez (1970, 1971, 1978). the majority of the clastic material was transported in the slavonia-srijem depression by the rivers and streams from the bosnian mountains and from mt. dilj. this is confirmed by the mineral composition of fluvial sediments which originated from the serpentine zone in bosnia (muti∆, 1993). the main direction of transport from south to north correlates with reducing proportions of the coarse-grained clasts and grain size in the same direction (urumovi∆ et al., 1978). in this way, in the southern part, along the sava river, gravel was predominantly deposited, and in the northern sections sand (mileti∆ et al., 1986a). the drava river and the streams flowing down the slopes of mt. krndija are the main distributors of clastic material in the drava depression. the drava river transports the material eroded in the area of the central alps, on the pohorje and kozjak massifs and from the slavonian mountains (babi∆ et al., 1978; muti∆, 1989). in eastern slavonia the river mostly deposits sand. the more frequently occurring gravel along the western margin of the study area was brought by the mt. krndija streams (urumovi∆, 1982). apart from the rivers and streams, maga© (1987b) discovered the traces of lakes by the rivers and deep pools. in the erdut area, large shallow marshes existed where rivers deposited sand in the high-water periods (veli∆ et al., 1985). in the pliocene, the –akovo-vinkovci and the vukovar plateaux were mostly submerged uplifts characterised by the deposition of mixed sedimentary material. one of components was transported from the north, respectfully the north-west, and another from the south or the south-west. in the vukovar plateau area, the fluvial, lacustrine and marsh sediments were determined (»i»uli∆-trifunovi∆ & galovi∆, 1985b). apart from the palaeoclimate conditions, sedimentation was influenced by tectonic movements which are 145baëani, ©parica & veliê: quaternary deposits as the hydrogeological system of eastern slavonia still active in eastern slavonia. the most important tectonic displacement is on the main faults that follow the northern and southern margin of the plateau and on the secondary parallel faults of the wnw-ese system. there is also a marked displacement on the faults of the nne-ssw system (hernitz, 1983). this system has an especially pronounced horizontal character of displacement (prelogovi∆ & veli∆, 1992). in the beginning of the upper pleistocene s i m i l a r sedimentary conditions were preserved. the risswürm interglacial was still characterised by an influx of coarse-grained clastic material, which is proved by palaeontological investigation of the topmost part of the gravely aquifer close to the sava river (muti∆, 1993). it seems that the extensive transport of the coarsegrained clastic material by surface waters stopped with the beginning of the last ice age the würm glacial. the most remarkable würm facies are the loess deposits that also cover a significant part of the study area. transported by strong winds, the loess grains were deposited everywhere in the lakes, pools and shallower marshes as well as on the mild morphologic land uplifts. in respect to that, the lake-marsh, marsh, marsh-continental and continental loess is differentiated (figs. 1 and 2). different types of loess at the same time depict the contemporary distribution of the land and water, which is of special importance for the reconstruction of the evolution of the plateaux. the typical continental loess is found only in the area of the vukovar plateau, erdut uplift and in the restricted area near the otok and komletinci. this means that land existed only in these areas at the time. the loess on the –akovo-vinkovci plateau was contemporaneously deposited in an aqueous environment. the following tectonic movements led to the uplift of the vinkovci area so that the loess that was in the beginning deposited in water was gradually covered by continental loess (galovi∆ & muti∆, 1984; muti∆, 1990). the contact between the aqueous and continental loess can be clearly observed in the quarry of the vinkovci brick-factory. during the entire upper pleistocene, in the western part of the plateau (the –akovo part) the wind-blown grains were deposited in the shallow water environment. due to neotectonic activity, this part of the plateau became land only in the holocene (muti∆, 1990). in addition to the loess, the upper pleistocene sediments in the drava depression are represented by river palaeoterraces and alluvial sands. the terraces are identified on the surface along the drava flow between the osijek and sarvaπ and along the danube from dalj to vukovar, and the alluvial sand deposits lie in the marginal north-western part of the explored area (figs. 1 and 2). a large part of the sava depression area is covered by marshy-lacustrine sediments of upper pleistocene age, deposition of which continued into the holocene. frequently, they are complicated to differentiate in the field from the marsh loess (©parica et al., 1987). due to the lack of organic matter, it is interpreted that these sediments were deposited in relatively clean water. the analyses of malacologic assemblages resulted in interpretation of the water environment with land nearby and marked oscillation of water level which produced repeated floods and drying-up periods (galovi∆ et al., 1989). warming at the pleistocene holocene boundary caused a change in composition of vegetation cover. the steppe was gradually replaced by woods (poje, 1986). changes in wildlife are also documented. in the early holocene there are still grazing herds of northeuropean moose (alces alces) , gigantic deer (m e g a c e ros) and european bison (bison priscus), and during the boreal there were common deer (cervus elaphus), wild oxen (bos primigenius), bear (ursus arctos ), wolf (c a nis lupus), lynx (felis) etc. domestication of some animals started in the boreal. it was firstly the dog, then the goat, sheep, oxen and some other animals. in the neolithic and the bronze ages, it was the horse, donkey, hen etc. (malez, 1979). the climatic changes at the end of the würm and the beginning of the holocene caused the melting of ice in the alpine and perialpine area and inflow of large masses of water in and around the study area. deposition of fluvial sediments started, followed by formation of river terraces. there are four genetic types of holocene sediments: river and creek alluvium, proluvial deposits, aeolian sands and marsh sediments (fig. 1). the river and creek sediments are found in the river channels of the sava, drava and danube, and of their larger tributaries. proluvial deposits cover the southern slopes of the erdut hill, as well as the northern margin of the –akovo-vinkovci plateau. they were formed by the surface erosion of the continental loess and accumulation of the eroded material in the area of contact with the aquatic loess. the proluvial deposits are thin and made of loose silt containing limestone concretions. aeolian sands are determined in the surroundings of valpovo, in the marginal north-western part of the studied area. actually, the sediments of this genetic type are very common in the drava valley west of the studied area, and it is only the tract with a maximal eastward reach that is encountered here. although less than 2 metres thick, t h e s w a m p d e p o s i t s cover large areas in the brodsko posavlje region and in eastern posavina. they represent the final phase of deposition of the lacustrine-marsh genetic type of sediments. in the drava area, these sediments infilled the larger and smaller forms of negative relief, that were due to the stagnant water transformed into the swamps or swamp forests. in fluvial seasons, some of the dried parts were again filled with water, and the depositional process renewed. this is ongoing today. the swamp deposits consist of the humus-peat enriched silt and silt with some sand, as well as of the silty clay. 146 geologia croatica 52/2 about a century ago, when the struggle for reclamation of this swampy land began, the lowest parts of the sava and drava depression were still covered by pools and swamps. there are works of pilar (1876) on the swamps south-east of osijek, and of bösendorfer (1952) on the pools and swamps in the areas of karaπica, vuka and vuëica rivers, in the bi-bosut depression, and in the areas of berava, spaëva and studva. they all had their maximal extent during the high waters of the drava and sava rivers. there are also the archaeological findings that are worth mentioning, because they indirectly depict the distribution of aquatic surfaces. the oldest settlements at present that were found in eastern slavonia are from the younger stone age the neolithic (6,000 3 , 5 0 0 b.c.) and pertain to the cultural layers named starëevac and sopot. these are the oldest settlements of farmers that were located in groups on the more elevated dry terrain along the rivers and lakes, but out of the reach of floods (minichreiter, 1992a, b). the remains of these cultures are found near the stari perkovci, vrpolje, –akovo, vinkovci, vukovar, otok, erdut hill and near osijek. 3.2. hydrogeological characteristics the permeable sediments saturated with drinking water were deposited during the middle pleistocene and part of the upper pleistocene, under conditions of cyclic sedimentation followed by tectonic movements. these depositional conditions resulted in pronounced lithological heterogeneity in both the horizontal and vertical directions. according to core determination of the shallowest 200 m of sediments in the stratigraphic column, five to seventeen permeable layers can be discerned in the drava depression. the number of layers depends on location, while some of them reach the maximal thickness of 40 m (figs. 3, 4 and 5). these permeable layers are mostly composed of fineto medium-grained sands with some gravel occasionally, (usually encountered in the basal parts of thicker sandstone layers). hydraulic conductivity is commonly in the range of 10-20 m/day, with the exception of some of the wells in osijek, where over 40 m/day was determined, and, in contrast wells in ostrovo, korog and borovo which have less than 10 m/day. the storativity is in the range of 4 x 10-5 to 3 x 10-3 while the transmissivity depends on the depth of drilling and is in a wide range of 70 -1000 m2/ d a y . the distribution of the net thickness of permeable layers in the entire studied area is shown in fig. 6, where it clearly depicts the depositional conditions as described above. the sediments of the sava depression can be divided into two units with essentially different hydrogeological properties. the first unit that lies in the south, along the sava, consists of a single gravel aquifer (fig. 2) with a maximal thickness exceeding 100 m. the lithological composition is dominated by fineto medium-grained gravel with 10-50 wt. % of sand. this layer has the most favourable hydrogeological characteristics in the triangle between the velika kopanica, gundinci and kruπevica. in this area, the gravel rarely contains more than 20 wt. % of sand, and the thinner beds of finer material appear only sporadically. the more pronounced lithological inhomogeneity is found in the area fig. 3 hydrogeological cross-section i-i’. 147baëani, ©parica & veliê: quaternary deposits as the hydrogeological system of eastern slavonia between the babina greda and ©titar and further to the east, where the gravel contains frequent interbeds of silty sand and clay. the mentioned aquifer has a hydraulic conductivity in the range of 30-≥200 m/day, the transmissivity is between 423 7344 m2/day, and storativity between 1.7 x 10-4 and 8 x 10-3. to the north and east of the gravel aquifer, lies the second hydrogeological unit of the sava depression. it consists of a system of sand aquifers that can number from 2 to 11 in the shallowest 200 m of sediments. the thickness of individual layers rarely exceeds 30 m. layers are mostly composed of fineto medium-grained sand and occasionally of coarse-grained sand. as in the drava depression, the thicker layers of sand contain some gravel in their basal parts, especially in the eastern section, in the localities of vranjevo, otok and slakovci. the hydraulic conductivity of these layers is in the range of 5.5 -37 m/day, the transmissivity is fig. 4 hydrogeological cross-section ii-ii’. fig. 5 hydrogeological cross-section iii-iii’. 148 geologia croatica 52/2 fig. 6 isolith map of permeable layers in the quaternary aquifer system. • -., • " , -• " • -. " • • ; ~"'-~ .-,. ~ _<f _ _ 1"_''''· ! _ _ ",_ 1) · 10" _ _ ,,_n·"_ _ _ of_ <'" / , , , . ----• ,<!, '" , ~ • -." , -,. , , ~ -/ -~ ~ ~ ~ -~ -, -~ , ---~ , , , i .~ • , , • , • 149baëani, ©parica & veliê: quaternary deposits as the hydrogeological system of eastern slavonia between 52 706 m2/day, and storativity between 1.3 x 10-44.3 x 10-3. in the first 120 m of sediments drilled on the –akovo-vinkovci plateau, between 3 to 8 aquifers were determined in the stratigraphic column. some of these layers were found to have a maximal thickness of 30 m (figs. 3, 4 and 5). these aquifers are made of fineto coarse-grained sand that often contains coarse-grained gravel, especially in the western part of the explored area. the hydraulic conductivity is in quite a wide range of 5-30 m/day, the transmissivity is between 52 and 413 m2/day, and storativity between 1.9x 1 0-4 a n d 4.4 x 10-3. the thickness of deposits that cover the eastern slavonia aquifer system is shown in fig. 7. the cover sediments over the entire area of eastern slavonia are composed of silty-clayey deposits with lenses and interbeds of sand. the low-permeability sediments between the aquifers at depth are of the same lithological composition. the leakage coefficient there is in the wide range of 1.3 x 10-54.3 x 10-3 day-1. over the entire study area, the groundwaters are recharged by the means of rainfall infiltration. the infiltration from the surface streams in natural conditions can practically be neglected in the drava depression. the surface drainage pattern in the studied part of the drava depression is such that it drains the groundwater both in periods of high and low waters. the situation in the sava depression is somewhat different. the sava river channel is cut into the gravel aquifer, thus putting it in direct hydraulic connection with the river. the high waters of the sava are registered in the wells up to 5 km further north, as far as the area of velika kopanica. during the low waters, the river waters are below the groundwater level which means that the sava drains the aquifer. alternatively, in conditions of extensive exploitation of the gravel layer, the inflow of sava waters would be the major recharge source. the rainfall infiltration on the plateaux is especially well developed in the eastern parts, because the aquifer system there is covered by the continental loess that has a significant vertical permeability. because of the terrain morphology, the hypsometric levels of groundwater are the highest in the area of –akovo-vinkovci and vukovar plateau, which means that groundwater flows from the plateau in the directions of the north-east and south-east, and there is the watershed along the plateau. 3.3. hydraulic function of the plateau in order to enable the analysis of lateral changes of sediments, especially on the contact between the plateau and depressions, a number of the n-s striking hydrogeological cross-sections were constructed. the sections illustrate the results of comprehensive correlation of all the acquired drilling data and well-logs (mostly e-logs) in the area of –akovo-vinkovci and vukovar plateau. only characteristic sections are shown in figs. 3, 4 and 5. the correlation of well data showed that the plateaux have undergone a spatially and temporally non-uniform uplift that resulted in differences of sediment deformation along the fault zones. the biggest displacements are registered on the southern fault zone, south of –akovo (fig. 3). thicker aquifers are bent and thinned but their lithological (and hydraulic) continuity is not broken. it is noted that tectonics within the plateau itself contributed to sediment deformation even more than the northern fault zone near tomaπanci. further to the east, in the area from ivankovo to vinkovci, the aquifer layers remained practically undisturbed along the fault zones, making the hydrogeological relations on the plateau the same as those in the depressions (fig. 4). the correlation of wells across the vukovar plateau showed a stronger deformation of sediments along the northern fault zone than on the southern one (fig. 5). some of the aquifers branch along the northern fault zone, but the continuity of the thicker layers is intact. while observing the cross-sections in figs. 3, 4 and 5, a significant vertical exaggeration must be noted, because it gives an impression of a higher deformation of sediments than that which actually exists. the same results were obtained by interpretation of geoelectrical measurements that were performed on a number of occasions by the geoelectrical department of the “geofizika” company from zagreb. on the fault zones, a few cross-sections have a characteristic reduction of the electric resistivity to a level of 5 ωm. there are bigger differences on the plateau itself. in the shallowest 100 m the zones were measured with resistivity under 20 ωm, and those with more than 65 ωm. in order to determine the hydraulic role of fault zones between the plateaux and depressions, the results of mathematical models that encompassed the plateau areas were analysed. two models were calculated (mileti∆ et al., 1986b, 1993), both of which tested the shallowest aquifer. in both cases, the model results showed that there is no hydraulic barrier along the fault zones. namely, the simulated and measured drawdowns correspond only in the case of the supposed continuity of the aquifer. putting the flow barrier along the fault line in the model, or even the reduced transmissivity, would result in unrealistically large simulated drawdowns in respect to the measured ones. 4. conclusion based on the analysis of all the acquired geological and hydrogeological data, it must be concluded that there is lithological continuity of the aquifer layers across the fault zones of the –akovo-vinkovci and vukovar plateaux, which means that there is no hydraulic barrier on the watershed between the sava and drava alluvial valley. the area of eastern slavonia between the drava and sava rivers is regarded as one hydraulic system that contains zones of different transmissivity. along the 150 geologia croatica 52/2 fig. 7 isopach map of low-permeable aquifer system roof. ,,. ...,-.... ', •... ,-_.',', --~ / , • , _. -----~ " .~. , , .. = • 151baëani, ©parica & veliê: quaternary deposits as the hydrogeological system of eastern slavonia zones of reduced transmissivity, the hydraulic connections are weakened, but not broken. such zones exist not only along the fault zones of the –akovo-vinkovci and vukovar plateau, but within the depressions and the plateau itself. the terrain morphology influenced the formation of both the surface and the underground watershed, parallel to the extension of the –akovo-vinkovci and vukovar plateau. in a hydraulic sense, the watershed represents a streamflow line. that is why, in order to construct a mathematical model of a certain drainage area (or of a part of the drainage area) with a marginal line along the watershed, the watershed has to be defined as a “zero flow boundary”. because of the single hydraulic entity, in the case of the draw-down reaching the boundary due to the excessive pumping, the groundwater will start flowing over the margin of the model. the bigger the draw-down at the margin, the bigger the flow, making the watershed more displaced from its natural position. 5. references babi∆, æ., »akarun, i., soka», a. & mraz, v. (1978): o geologiji kvartarnih naslaga porjeëja rijeke drave.geol. vjesnik, 30/1, 43-61, zagreb. bösendorfer, j. (1952): istoëna granica tomislavove, kreπimirove i zvonimirove hrvatske u savsko-dravskom interamniju.rad jugosl. akad. znan. umjet., 286, 143-170, zagreb. brki∆, m., galovi∆, i. & buzaljko, r. (1989): osnovna geoloπka karta sfrj 1:100.000. list vinkovci l34-98.geol. zavod zagreb & geoinæenjering sarajevo (1979-1985), sav. geol. zavod, beograd. buzaljko, r., vujnovi∆, l. oluji∆, j. & markovi∆, s. (1987): osnovna geoloπka karta sfrj 1:100.000. list brëko l34-110.geoinæenjering sarajevo & geol. zavod zagreb (1985), sav. geol. zavod, beograd. »i»uli∆-trifunovi∆, m. & galovi∆, i. (1985 a): osnovna geoloπka karta sfrj 1:100.000. list baëka palanka l34-99.geol. inst. beograd & geol. zavod zagreb (1972-1980), sav. geol. zavod, beograd. »i»uli∆-trifunovi∆, m. & galovi∆, i. (1985 b): osnovna geoloπka karta sfrj 1:100.000. tumaë za list baëka palanka l34-99.geol. inst. beograd & geol. zavod zagreb (1983), sav. geol. zavod, beograd, 46 p. galovi∆, i. & muti∆, r. (1984): gornjopleistocenski sedimenti istoëne slavonije (hrvatska).rad jugosl. akad. znan. umjet., 411 (razr. prir. znan., 20), 299-356, zagreb. galovi∆, i., brki∆, m. & buzaljko, r. (1989): osnovna geoloπka karta sfrj 1:100.000. tumaë za list vinkovci l34-98.geol. zavod zagreb (1987) & geoinæenjering sarajevo (1979), sav. geol. zavod, beograd, 49 p. he∆imovi∆, i. (1985): osnovna geoloπka karta sfrj 1:100.000. list donji miholjac l34-73.geol. zavod zagreb (1981-1984), sav. geol. zavod, beograd. hernitz, z. (1983): dubinski strukturno-tektonski odnosi u podruëju istoëne slavonije.phd thesis, jugosl. komitet svjet. kongr. za naftu, “nafta”, zagreb, 221 p. korolija, b. & jami»i∆, d. (1989a): osnovna geoloπka karta 1:100.000. list naπice l34-85.geol. zavod zagreb (1988), sav. geol. zavod, beograd. korolija, b. & jami»i∆, d. (1989b): osnovna geoloπka karta sfrj 1:100.000. tumaë za list naπice l34-85.geol. zavod zagreb (1988), sav. geol. zavod, beograd, 40 p. maga©, n. (1987a): osnovna geoloπka karta sfrj 1:100.000. list osijek l34-86.geol. zavod zagreb (1981-1987), sav. geol. zavod, beograd. maga©, n. (1987b): osnovna geoloπka karta sfrj 1:100.000. tumaë za list osijek l34-86.geol. zavod zagreb (1986), sav. geol. zavod, beograd, 54 p. malez, m. (1970): izumrli sisavci slavonije.zbornik radova i. znanstvenog sabora slavonije i baranje, 101-105, osijek. malez, m. (1971): kvartarogeoloπke karakteristike brodskog posavlja.radovi centr. org. nauën. rada u vinkovcima, jugosl. akad. znan. umjet., 1, 373383, zagreb. malez, m. (1978): paleontoloπka i kvartargeoloπka istraæivanja u 1973. godini.ljetopis jugosl. akad. znan. umjet., 78, 559-572, zagreb. malez, m. (1979): kvartarna fauna jugoslavije. praistorija jugoslavenskih zemalja 1. paleolitsko i mezolitsko doba.akad. nauka bosne i herceg., 5579, sarajevo. mileti∆, p., ba»ani, a., mayer, d. & capar, a. (1986a): prilog poznavanju hidrogeoloπkih znaëajki prve hidrogeoloπke zone na podruëju istoëne slavonije.geol. vjesnik, 39, 137-150, zagreb. mileti∆, p., heinrich-mileti∆, m. & ba»ani, a. (1986b): pristup interpretaciji podataka pokusnog crpljenja.geol. vjesnik, 39, 151-164, zagreb. mileti∆, p., heinrich-mileti∆, m. & ba»ani, a. (1993): konceptualni hidrogeoloπki model za hidrogeoloπki sustav istoëne slavonije.rud.-geol.naftni zbornik, 5, 65-73, zagreb. minichreiter, k. (1992a): starëevaëka kultura u sjevernoj hrvatskoj.unpublished phd thesis, university of zagreb, 104 p. 152 geologia croatica 52/2 minichreiter, k. (1992b): ranoneolitiëka arhitektura sjeverne hrvatske.poroëilo raz. pal. neol. eneol. v sloveniji, 20, 17-26, ljubljana. muti∆, r. (1989): korelacija kvartara istoëne slavonije na osnovi podataka mineraloπko-petrografskih analiza (istoëna hrvatska, jugoslavija). dio i: dravska potolina.acta geologica, 19/1, 1-60, zagreb. muti∆, r. (1990): korelacija kvartara istoëne slavonije na osnovi podataka mineraloπko-petrografskih analiza (istoëna hrvatska, jugoslavija). dio ii: lesni ravnjak.acta geol., 20/2, 29-80, zagreb. muti∆, r. (1993): korelacija kvartara istoëne slavonije na osnovi podataka mineraloπko-petrografskih analiza (istoëna hrvatska). dio iii: slavonsko-srijemska potolina.acta geol., 23/1, 1-37, zagreb. pilar, gj. (1876): podravina, djakovπtina i diljgora.rad jugosl. akad. znan. umjet., 33, 38-57, zagreb. poje, m. (1986): ekoloπke promjene na vukovarskom prapornom ravnjaku proteklih cca 500.000 godina.geol. vjesnik, 39, 19-42, zagreb. poje, m., juri©i∆-pol©ak, z. & ©parica, m. (1995): srednjopleistocenska malakofauna glogovice kod slavonskog broda (slavonija, hrvatska).in: vlahovi∆ i., veli∆, i. & ©parica, m. (eds.): first croatian geol. congr., opatija, proceedings, 2, 459-464, zagreb. prelogovi∆, e. & veli∆, j. (1992): correlation of quaternary sediments and tectonic activity of the eastern part of the drava river depression.geol. croatica, 45, 151-162. prelogovi∆, e., jami»i∆, d., aljinovi∆, b., veli∆, j., safti∆, b. & draga©, m. (1995): dinamika nastanka struktura juænog dijela panonskog bazena. in: vlahovi∆ i., veli∆, i. & ©parica, m. (eds.): first croatian geol. congr., opatija, proceedings, 2, 481-486, zagreb. soka», a. (1976): pleistocenska fauna ostrakoda iz nekih buπotina u istoënoj slavoniji (sjeverna hrvatska).geol. vjesnik, 29, 159-172. soka», a. & harten, van d. (1978): ilyocypris slavonica n. sp. (crustacea, ostracoda) from the pleistocene of vinkovci (slavonia, north croatia) and of tegelen (the netherlands).geol. vjesnik, 30/1, 219-223. soka», a., dragi»evi∆, i. & veli∆, j. (1982): biostratigrafske i litoloπke odlike neogenskih i kvartarnih sedimenata nekih buπotina okolice osijeka.geol. vjesnik, 35, 9-20. ©parica, m. (1987): osnovna geoloπka karta sfrj 1:100.000. list slavonski brod l34-97.geol. zavod zagreb & geoinæenjering sarajevo (1986), sav. geol. zavod, beograd. ©parica, m., buzaljko, r. & paveli∆, d. (1987): osnovna geoloπka karta sfrj 1:100.000. tumaë za list slavonski brod l34-97.geol. zavod zagreb & geoinæenjering sarajevo (1986), sav. geol. zavod, beograd, 56 p. trifunovi∆, s. (1985): osnovna geoloπka karta sfrj 1:100.000. tumaë za list odæaci l34-87.geol. inst. beograd (1972-1983) & “nafta-gas” novi sad (1973-1983), sav. geol. zavod, beograd, 54 p. trifunovi∆, s. & stojadinovi∆, p. (1985): osnovna geoloπka karta sfrj 1:100.000. list odæaci l34-87.geol. inst. beograd & “nafta-gas” novi sad (1984), sav. geol. zavod, beograd. urumovi∆, k. (1982): hidrogeoloπke znaëajke istoënog dijela dravske potoline.unpublished phd thesis, university of belgrade, 138 p. urumovi∆, k. & soka», a. (1974): o kvartarnim naslagama æupanje (istoëna slavonija, sr hrvatska).geol. vjesnik, 27, 319-330. urumovi∆, k., hernitz, z., ©imon, j. & veli∆, j. (1976): o propusnom mediju kvartarnih te gornjo i srednjopliocenskih naslaga sjeverne hrvatske.zbornik radova 4. jugoslavenskog simpozija o hidrogeologiji i inæenjerskoj geologiji, 1, 395-410, skoplje. urumovi∆, k., hernitz, z. & ©imon, j. (1978): o kvartarnim naslagama istoëne posavine (sr hrvatska).geol. vjesnik, 30/1, 297-308. veli∆, j. & durn, g. (1993): alternating lacustrinemarsh sedimentation and subaerial exposure phases during quaternary: preëko, zagreb, croatia.geol. croatica, 46/1, 71-91. veli∆, j. & safti∆, b. (1996): dubinskogeoloπki odnosi podruëja smetliπta “jakuπevec” ëimbenik sanacije.zbornik radova iv. meunarodnog simpozija “gospodarenje otpadom zagreb ‘96”, 197205, zagreb. veli∆, j., dragi»evi∆, i. & prelogovi∆, e. (1985): geoloπki odnosi kvartarnih naslaga okolice erduta (istoëna hrvatska).geol. vjesnik, 38, 87100. vrhov»i∆, j., moji»evi∆, m., an–elkovi∆, i., markovi∆, b., pavlovi∆, z., raj»evi∆, d., prtoljan, b. & galovi∆, i. (1986): osnovna geoloπka karta sfrj 1:100.000. list bijeljina l34111.geoinæenjering sarajevo, geol. inst. beograd & geol. zavod zagreb, sav. geol. zavod, beograd. manuscript received september 23, 1999. revised manuscript accepted november 12, 1999. 02-faris.indd faris and farouk: integrated biostratigraphy of two upper maastrichtian – palaeocene successions in north-central sinai, egypt 139 � ab stra ct integration of the calcareous nannofossil and planktonic foraminiferal biostratigraphies has been performed for the upper maastrichtian – palaeocene successions at gebel umm khushayb and west el-hassana sections (north-central sinai, egypt). the studied successions include the uppermost part of the sudr, dakhla, and tarawan formations and their lateral coeval beida formation. biostratigraphic analysis has allowed recognition from zone cf2 to zone p4 in terms of planktonic foraminifera and from zone cc26c to zone np7/8 in terms of calcareous nannofossils. the maastrichtian/palaeogene (k/pg) boundary is characterized by an erosional surface that marks a hiatus between the sudr/dakhla or sudr/beida formation boundaries, as confi rmed by the absence of the planktonic foraminiferal cf1 to p1a zones and their equivalent nannofossil zones (top part of cc26c to lowest part of zone np3). the danian/ selandian (da/se) boundary lies in the upper part of the dakhla formation within the top of nannofossil zone np4, and within planktonic foraminiferal zone p3b, similar to that of the global standard stratotype-section and point (gssp) of the d/s boundary which has recently been chosen at the zumaia section, northern spain. a minor hiatus was observed across the selandian/thanetian boundary as indicated by a lithological change and a very condensed zone np6, corresponding to the dakhla and tarawan formation boundary in the west el-hassana section. keywords: biostratigraphy, calcareous nannofossils, danian/selandian boundary, planktonic foraminifera, northcentral sinai integrated biostratigraphy of two upper maastrichtian – palaeocene successions in north-central sinai, egypt � mahmoud faris1 and sherif farouk2 1 geology department, faculty of science, tanta university, egypt; (mhmfaris@yahoo.com) 2 egyptian petroleum research institute, nasr city, 11727, egypt; (geo.sherif@hotmail.com) doi: 104154/gc.2012.10 geologia croatica 65/2 139–160 3 figs. 4 tabs. 3 pls. zagreb 2012 geologia croaticageologia croatica 1. introduction the palaeocene successions in egypt are marked by widely distributed, condensed successions rich in calcareous planktonic faunal assemblages with distinct vertical and lateral facies changes. a considerable number of previous papers deal with the biostratigraphy of the palaeocene of sinai (e.g. lüning et al., 1998; marzouk & lüning, 1998; elnady & shahin, 2001; samir, 2002; ayyad et al., 2003; speijer, 2003; al-wosabi & abu shama, 2007; faris & salem, 2007; faris & abu shama, 2007; farouk & faris, 2008). the present study provides the fi rst information on the biostratigraphy at gebel umm khushayb and only a few small works have been undertaken on the el-hassana area (el-deeb et al., 2000 & faris et al., 2000). these authors placed the palaeocene stage boundaries according to older concepts (before defi nigeologia croatica 65/2geologia croatica 140 specimen /2–5 fov), r= rare (one specimen/6–10 fov) and vr=very rare (one specimen/ more than 10 fov). for the planktonic foraminifera, about 200g of dry rock samples were disaggregated in water and washed through a 63μm sieve. the relative abundance of planktonic foraminiferal taxa are defi ned as follows: abundant, >26%; common, 16–25%; few, 6–15%; rare, 2–5%; very rare, <2%. 3. geological setting and lithostratigraphy tectonically, said (1962) divided egypt into two major provinces, the deformed unstable shelf to the north, and the nearly horizontal and less deformed stable shelf to the south (fig. 1). the syrian arc fold belt is one of the best-known structural features in the unstable shelf, and it played an important role in controlling the confi guration of the depositional sequences and the great complexity of changes both in facies and thickness (farouk & faris, 2008). the study area lies in north-central sinai of the unstable shelf and is characterized by complex uplifts and domal anticlines of the syrian arc fold belt, that were formed during the closure of neo-tethys during the convergence of the africanarabian craton (stampfli et al., 1995). maastrichtian – palaeocene siliciclastic/carbonate outcrops are widely distributed in north-central sinai, where the campanian-maastrichtian sudr formation overlies unconformably the palaeocene sediments, which correspond to four well-defi ned formations from oldest to youngest are; dakhla formation, tarawan formation and lowermost part of the esna formation and their lateral coeval beida formation. the following is a detailed lithostratigraphic description of the detected upper maastrichtian – palaeocene formations in the study area, given from older to younger (fig, 2). sudr formationcampanian-maastrichtian the campanian-maastrichtian sudr formation (ghorab, 1961) is widespread throughout the foot slopes of sinai. it unconformably overlies the dakhla or bedia formations with a sharp lithological contact. the sudr formation is subdivided from base to top into the markha and abu zenima members. the study measured part of the sudr formation deals only with the uppermost part of abu zenima member (upper maastrichtian). it consists of argillaceous li me stone with a measured thickness of about 2–2.5 m in the study sections (fig. 2). dakhla formationdanian-selandian the term dakhla formation was fi rstly used by said (1961) to describe the maastrichtian-palaeocene siliciclastics and carbonate deposits in dakhla oasis, western desert. in northern latitudes 26º30’ in egypt, the lower part of the dakhla formation is generally laterally equivalent to carbonate facies (the sudr and khoman formations). therefore in the sinai peninsula, the dakhla formation belongs to the palaeocene and it overlies unconformably the tion of the global stratotypes of the danian/selandian and selandian/thanetian boundaries). in the two study sections, the k/pg, de/se and se/th remain unclear and not been precisely identifi ed. however, many discrepancies in the palaeocene bioevents could not be clarifi ed because either taxonomically different concepts caused uncertainties in correlation of the palaeocene zones, especially in the southern tethyan realm, (orue-etxebarria et al., 2007; arenilas, 2012), or these marker bio-events are recorded from different palaeolatitudes showing considerable variations in age (farouk & faris, 2011). the main purpose of this research was to accurately correlate the palaeocene bio-events with the standard biostratigraphic scales, using both calcareous nannofossils and planktonic foraminifera, for two upper maastrichtian – palaeocene successions in north-central sinai, and to discuss in details the cretaceous/palaeogene (k/pg), the danian/selandian (da/se) and the selandian/thanetian (se/th) boundaries in the studied successions. 2. materials and methods seventy-six rock samples were collected, approximately every. 25–50 cm from the two studied sections at gebel umm khushayb (30º14’27”n and 33º13’33”e) and west el-hassana (30º25’40”n and 33º46’41”e), (fig. 1). calcareous nannofossils were analyzed using standard smear slides, which were examined using a light photomicroscope at 1250x magnifi cation. a qualitative estimation of the abundance of calcareous nannofossil taxa are noted as follows: a= abundant (more than 5 specimens /fi eld of view, fov), c=common (1–5 specimens/fov), f=frequent (one figure 1: location map of the study area. faris and farouk: integrated biostratigraphy of two upper maastrichtian – palaeocene successions in north-central sinai, egypt geologia croatica 141 maastrichtian sudr formation and also underlies the tarawan formation, with very clear contact, and can be easily recognized in the fi eld. it consists mainly of moderately hard, greenish grey monotonous pelagic calcareous mudstone with fl ooded well-diversifi ed calcareous planktonic assemblages with thicknesses ranging from 20 to 25 m in the west elhassana section. tarawan formationthanetian the tarawan formation (awad & ghobrial, 1965) is composed of hard to moderately hard, massive yellowish white argillaceous limestone, partly limonitic with a thickness of 2 to 4 m in the west el-hassana section. the partly resistant, light-coloured limestone of this unit is clearly distinguished from the overlying and underlying dark-colored figure 2: stratigraphic correlation of the studied sections in the north-central sinai. calcareous nannofossil schemes are after martini (np, 1971) and varol (ntp, 1989) and sissigh (cc, 1977). planktonic foraminiferal schemes are after berggren & pearson (p, 2005). geologia croatica 65/2geologia croatica 142 soft shales. in egypt, the dakhla formation is overlain by the tarawan formation which includes, at its upper part, the socalled “velascoensis event” with notable changes in the patterns of sedimentation in late palaeocene time. the event that produced those changes is believed to be primarily tectonic coupled with global sea-level fall (strougo, 1986). beida formationpalaeocene the term beida formation was fi rstly used by allam & khalil (1988) based upon predominant carbonate deposits at wadi beida, north of gebel arif el-naqa. it is equivalent to the palaeocene siliciclastic/carbonate of the esna formation, which is recorded in different parts of egypt. in the study area, the beida formation has a wide distribution in the submerged palaeo-high areas around central sinai, extending from gebel umm khushayb to ras sudr. it unconformably overlies and underlies the sudr and thebes formations, respectively. the beida formation attains a total thickness of 40 m and is composed of greenish gray marl, argillaceous limestone, and well-bedded chalky limestone with chert bands in the gebel gebel umm khushayb section. 4. biostratigraphy the biostratigraphy is evaluated here based on the cretaceous foraminiferal (cf) zonal scheme of li & keller (1998) and on the palaeocene (p) zonal scheme of berggern & pearson (2005). these zonal schemes are applied in the present study to provide a much improved biostratigraphic framework. for the calcareous nannofossil zonation, the cretaceous zonal scheme of sissingh (1977) and the palaeogene zonal scheme of martini (np, 1971) and varol (ntp, 1989) have been applied. the distribution of the calcareous nannofossils and planktonic foraminifera in the two studied sections are shown in tables 1–4. the most important foraminifera and calcareous nannofossil taxa are fi gured in three plates (1–3). abbreviations used fo= first occurrence, lo= last occurrence; fco= first common occurrence; fro= first rare occurrence. the following is the description of the established calcareous nannofossil and planktonic foraminiferal biozones arranged from older to younger. 4.1. calcareous nannofossils 4.1.1. micula prinsii subzone (cc26c) defi nition: the micula prinsii subzone is defi ned as the interval from the fo of micula prinsii perch-nielsen to the increased frequency of thoracosphaera operculata bramlette & martini. occurrence: this zone occupied the upper most part of the sudr formation and is represented by samples 220–221 (2 m thick) in umm khushayb; and samples 1–6 in west elhassana (2.5 m thick). characteristic species: the most important taxa also identifi ed from this subzone are: ahmuellerella octoradiata (gorka), arkhangelskiella cymbiformis vekshina, chiastozygus amphipons (bramlette & martini), stradneria crenulala (bramlette & martini), cribrosphaerella ehrenbergii (arkhangelsky), cyclagelosphaera reinhardtii (perch-nielsen), eiffellithus gorkae reinhardt, lithraphidites quadratus bramlette & martini, lucianorhabdus cayeuxii deflandre, manivitella pemmatoidea (deflandre in manivit), microrhabdulus decoratus deflandre, micula decussata vekshi na, zygolithus crux (deflandre & pert), and others (tables 1 & 2). rare specimens of m. murus (martini) and m. prinsii perch-nielsen are recorded in the topmost part of the sudr formation in the studied sections. remarks: the micula prinsii subzone was informally defi ned by perch-nielsen (1979) and corresponds to the upper part of zone cc26 of sissingh (1977). this subzone is a correlative of the latest maastrichtian. however, its upper limit cannot be determined with accuracy in the two studied sections due to a large hiatus observed at the base of the palaeocene. plate 1 1–2 arkhangelskiella cymbiformis vekshina, 1959, sample 2, west el-hassana section. 3 watznaueria barnesae (black in black & barnes, 1959), sample 221, gebel umm khushayb section. 4 chiastozygus amphipons (bramlette & martini, 1964), sample 4, west el hassana section. 5 braarudosphaera bigelowii (gran & braarud, 1935), sample 3, west el hassana section. 6–7 microrhabdulus decoratus deflandre, 1959, sample 221, gebel umm khushayb section. 8 lithraphidites carniolensis deflandre, 1963, sample no.5, west el-hassana section. 9–10 placozygus sigmoides (bramlette & sullivan, 1961), sample 32, west el-hassana section. 11 eiff ellithus gorkae reinhardt (1965), sample 220, gebel umm khushayb section. 12 zeugrhabdotus pseudanthophorus (bramlette & martini, 1964), sample 3, west el-hassana section. 13 thoracosphaera operculata bramlette & martini, 1964, sample 228, gebel umm khushayb section. 14 thoracosphaera saxea stradner, 1961, sample 12, west el-hassana section. 15 lucianorhabdus cayeuxii deflandre, 1959, sample 220, gebel umm khushayb sectio. 16–17 micula prinsii perch-nielsen, 1979, sample1, west el-hassana section. 18–19 micula murus (martini, 1961), sample 2, west el-hassana section. 20 cribrosphaerella ehrenbergii (arkhangelsky, 1912), sample 221, gebel umm khushayb section. 21–22 micula decussata vekshina, 1959, sample 222, gebel umm khushayb section. 23 zygodiscus spiralis bramlette & martini, 1964, sample 4, west el-hassana section. 24 manivitella pemmatoidea (deflandre in manivit, 1965), sample 221, gebel umm khushayb section. 25 tetrapodorhabdus decorus (deflander in deflander & fert, 1954), sample 5, west el-hassana section. faris and farouk: integrated biostratigraphy of two upper maastrichtian – palaeocene successions in north-central sinai, egypt geologia croatica 143 micula murus is one of the rare maastrichtian species and clearly restricted to low latitudes (worsley and martini, 1970; thierstein, 1981; gardin, 2002; lees, 2002). it was used for recognition of the uppermost maastrictian (lamolda & gorostidi, 1992; pospical, 1994; bernaola & monechi, 2007 and many others). geologia croatica 65/2geologia croatica 144 plate 2 1–2 ellipsolithus macellus (bramlette & sullivan, 1961), sample 9, west el-hassana section. 3 chiasmolithus edentulus van heck & prins, 1987, sample 22, west el-hassana section. 4 neochiastozygus perfectus perch-nielsen, 1971, sample 247, gebel umm khushayb section. 5 neochiastozygus junctus (bramlette & sullivan, 1961), sample 242, gebel umm khushayb section. 6 fasciculithus tympaniformis hay & mohler in hay et al., 1967, sample 40, west el-hassana section. 7 fasciculithus billii perch-nielsen, 1971, sample 42, west el-hassana section. 8 fasciculithus janii perch-nielsen, 1971, sample 36, west el-hassana section. 9 fasciculithus pileatus bukry, 1973, sample 242, gebel umm khushayb section. 10 fasciculithus involutus bramlette & sullivan, 1961, sample no.40, west el-hassana section. 11 fasciculithus alanii perch-nielsen, 1971, sample 45, west el-hassana section. 12–13 sphenolithus primus perch-nielsen, 1971, sample 245, gebel umm khushayb section. 14 toweius eminens (bramlette & sullivan, 1961), sample 247, gebel umm khushayb section. 15 cruciplacolithus primus perch-nielsen, 1977, sample no.224, gebel umm khushayb section. 16 chiasmolithus danicus (brotzen, 1959), sample 7, west el-hassana section. 17 cruciplacolithus tenuis (stradner, 1961), sample 10, west el-hassana section. 18 chiasmolithus bidens (bramlette & sullivan, 1961), sample 248, gebel umm khushayb section. 19 markalius inversus (deflandre in deflandre & fert, 1954), sample no.6, west el-hassana section. 20–21 ericsonia subpertusa hay & mohler, 1967, sample no.20, west el hassana section. 22 heliolithus kleinpellii sullivan, 1964, sample no.42, west el-hassana section. 23 discoaster mohleri bukry & percival, 1971, sample no. 45, west el-hassana section. 4.1.2. chiasmolithus danicus zone (np3) defi nition: the chiasmolithus danicus zone is defi ned as the interval from the fo of chiasmolithus danicus (brotzen) to the fo of ellipsolithus macellus (bramlette & sullivan). occurrence: this zone occupied the lowermost part of the dakhla and bedia formations and is represented by samples 222–227 (2.5 m thick) in umm khushayb; and samples 7–8 in west el-hassana (0.2 m thick). characteristic species: the most characteristic species of this zone are: cruciplacolithus tenuis (stradner), c. primus perch-nielsen, ericsonia subpertusa hay & mohler, e. cava (hay & mohler) and coccolithus pelagicus (wallich). remarks: the vanishing cretaceous species are those extinct at the k/pg boundary, and the cretaceous persistent species are those calcareous nannofossil genera and species that are known to occur in the cretaceous and survive into the palaeocene (perch-nielsen, 1985b). the np3 zone is characterized by a decrease of cretaceous vanishing species. in the two studied sections, cretaceous persistent species are very rare in this zone and only a few specimens of thoracosphaera operculata bramlette & martini, placozygus sigmoides (bramlette & sullivan) and cyclagelosphaera reinhardtii (perch-nielsen) dominate the assemblage. this zone has a reduced thickness in both the studied sections. cruciplacolithus edwardsii romein fi rst appears simultaneously with the fo of ch. danicus (base np3). the identifi ed zone np3 is equivalent to zone np3 of martini (1971), the upper part of the cruciplacolithus tenuis zone of romein (1979), the cp2 zone of okada & bukry (1980), faris & abu shama (2007) and faris & salem (2007). 4.1.3. ellipsolithus macellus zone (np4) defi nition: the fo of ellipsolithus macellus (bramlette & sullivan) is used to defi ne the base of zone np4, and the fo of fasciculithus tympaniformis hay & mohler defi ned its top (martini, 1971). occurrence: this zone occupied the middle part of the dakhla and bedia formations, represented by samples 228– 244 (14.5m thick) in umm khushayb; and samples 9–39 in west el-hassana (19 m thick). characteristic species: the fos of fasciculithus ulii perch-nielsen, f. billii perch-nielsen, f. bitectus romein, f. pileatus bukry, f. involutus bramlette & sullivan and f. janii perch-nielsen occur within the zone np4 in the two study sections. remarks: according to the palaeocene zonation of varol (1989), the zone np4 in west el-hassana and umm khushayb sections can be divided into three subzones, ntp6, ntp7 and ntp8. varol (1989) subdivided zone ntp7 and ntp8 into several subzones. in the present study, it was so diffi cult to subdivide these two biozones into several subzones due to the extreme condensation of this interval. on the other hand, zone np4 could be divided into two subzones; np4a, ellipsolithus macellus-sphenolithus primus subzone, it is defi ned from the fo of e. macellus (bramlette & sullivan) to the fo of sphenolithus primus perch-nielsen and np4b, sphenolithus primus -fasciculithus tympaniformis defi nes from the fo of sphenolithus primus to the fo of fasciculithus tympaniformis (quillévéré et al., 2002 and faris et al., 2005). this subdivision was applied in the current study. a small hiatus is suggested at the np3/np4 zonal boundary in the two studied sections, based on the absence of the uppermost part of zone np3 and the basal part of faris and farouk: integrated biostratigraphy of two upper maastrichtian – palaeocene successions in north-central sinai, egypt geologia croatica 145 zone np4 (absence of subzone ntp5b and ntp5c and most probably the lowermost of zone ntp6 of varol, 1989). also a minor hiatus is detected at the np3/np4 zonal boundary of the northern scarp of the farafra oasis (tantawy et al., 2003). the ntp6 subzone is defi ned as the interval from the fo of ellipsolithus macellus to the lo of neochiastozygus imbriei haq & lohmann and n. eosaepes perch-nielsen. geologia croatica 65/2geologia croatica 146 plate 3 1 heterohelix globulosa (ehrenberg, 1840), sample 3, west el-hassana section. 2 heterohelix navarroensis loeblich, 1951, sample 6, west el-hassana section. 3 heterohelix labellosa nederbagt, 1991, sample 220, umm khyushab section. 4 pseudoguembelina costulata (cushman, 1938), sample 221, umm khyushab section. 5–6 globanomalina compressa (plummer, 1926), sample 229, umm khyushab section. 7 globanomalina pseudomenardii (bolli, 1957), sample 247, umm khyushab section. 8–10 praemurica inconstans (subbotina, 1953), sample 25, west el-hassana section. 11–13 morozovella trinidadensis (bolli, 1957), sample 25, west el-hassana section. 14–15 igorina albeari (cushman & bermudez, 1949), sample 36, west el -hassana section. 16–18 morozovella angulata (white, 1928), sample 34, west el-hassana section. 19 morozovella conicotruncata (subbotina, 1947), sample 240, umm khyushab section. 20–21 morozovella occlusa (loeblich & tappan, 1957), sample 240, umm khyushab section. 22 morozovella pasionensis (bermúdez, 1961), sample 34, west el-hassana section. 23 acarinina strabocella (loeblich & tappan, 1957), sample 34, west el-hassana section. 24–25 parasubbotina pseudobulloides (plummer, 1926), sample 224, umm khyushab section. 26–27 parasubbotina varianta (subbotina, 1953), sample 246, umm khyushab section. 28 subbotina triangularis (white, 1928), sample 34, west el-hassana section. 29 subbotina triloculinoides (plummer, 1926), sample 25, west el-hassana section. 30 subbotina velascoensis (cushman, 1925), sample 252, umm khyushab section. scale bar=100 μm in all fi gures. the distribution of ellipsolithus macellus is considered as being controlled by preservation (dissolution) (monechi et al., 1985) or different palaeoecological conditions (backman, 1986, monechi et al., 1985). in the study sections, e. macellus, shows a rare and sporadic presence throughout the study interval which may be a result of dissolution and /or the effect of diagenesis. the subzone ntp7 defi nes the stratigraphic interval from the los of neochiastozygus imbriei and n. eosaepes to the fco (first common occurrence) of sphenolithus primus. the fo of chiasmolithus edentulus marks the base of subzone ntp7b of varol (1989) and occurs within zone ntp7 in the west el-hassana and umm khushayb sections. according to varol (1989), the fo of this taxon can be used to directly correlate tethys and the type area across the d/s boundary. the fi rst occurrence of ch. edentulus in the study sections is easily correlated with the type area of the danian/selandian boundary. the ntp8 has been defi ned to include the interval from the fo of sphenolithus primus to the fo of fasciculithus tympaniformis. previous studies have indicated that the occurrences of sphenolithus and fasciculithus (palaeocene taxa) are closely related. it is generally believed that the genus sphenolithus appears just below the genus fasciculithus (e.g. romein, 1979; backman, 1986; berggren et al., 1995), although other authors observed a reverse setting in the relative stratigraphic position of the two biohorizons (varol, 1989; berggren et al., 2000). the onset of the fi rst radiation of fasciculithus species occurs in samples 24 and 240 in the west el-hassana and umm khushayb sections, respectively. the onset of the second radiation of fasciculithus taxa occurs in samples 36 in the west el-hassana section and in sample 242 in the umm khushayb section. radiation of fasciculithus (f. pileatus, f. bitectus, f. involutus, f. janii, and f. ulii) fi rst occurred in higher levels above the fo of s. primus in the study area. as proposed by perch-nielsen (1985b) the fo of neochiastozygus perfectus perch-nielsen was used for delineating the base of zone np5 in north sea area. in the zumaia section, the fo of this taxon occurs above the first common occurrence (fco) of s. primus and immediately below the lco of braarudosphaera (dinares-turell et al., 2007). in the two studied sections, n. perfectus fi rst appears within zone np4 (zone ntp7). the fo of n. perfectus in zone np4 in the study sections is considered to be earlier than reported in the north sea area, and it is therefore apparently a diachronous event and must be used with caution for long distance corre lation. 4.1.4. fasciculithus tympaniformis zone (np5) defi nition: the fi rst occurrence (fo) of fasciculithus tympaniformis is used to defi ne the base of zone np5 and the fo of heliolithus kleinpellii sullivan defi nes its top. occurrence: this zone occupied the interval from the upper part of the dakhla and bedia formations, samples 245– 249 (3 m thick) in the umm khushayb section, and samples 40–41 in the west el-hassana section (1.5 m thick). characteristic species: the most characteristic species of this zone include those of zone np4 in addition to fasciculithus tympaniformis. remarks: according to perch-nielsen (1985b), toweius eminens (bramlette & sullivan) fi rst appears within zone np5. in the zumaia section, the lowest occurrence of toweius eminens occurs in the middle part of np5 (dinarès-turell et al., 2007). at umm khushayb, this species (toweius eminens) fi rst occurs within np5, while in the west el-hassana section, t. eminens is fi rst recorded within the upper part of zone np4. in the study sections,zone np5 corresponds to np5 zone of martini (1971), the fasciculithus tympaniformis faris and farouk: integrated biostratigraphy of two upper maastrichtian – palaeocene successions in north-central sinai, egypt geologia croatica 147 geologia croatica 65/2geologia croatica 148 ta bl e1 : st ra tig ra ph ic d is tr ib ut io n of th e id en tifi e d c al ca re ou s n an no fo ss ils in w es t e l-h as sa na se ct io n , n c si ni a, e gy pt ag e fo rm at io n sa m pl e n o. a bu nd an ce pr es er va ti on n an no fo ss il zo ne cretaceous taxa survivor taxa w at zn au er ia b ar ne sa e m ic ul a de cu ss at a ar kh an ge lsk ie lla cy m bi fo rm is cr ib ro sp ha er el la e hr en be rg ii el lip so lit hu s t ur ris ife lli m ic ro rh ab du lu s d ec or at us lu ci an or ha bd us ca ye ux ii ei ff e lli th us g or ka e cr ib ro co ro na g al lic a zy go di sc us sp ira lis pr ed isc os ph ae ra cr et ac ea te tra po do rh ab du s d ec or us m ic ul a pr in sii rh ag od isc us a sp er li th ra ph id ite s c ar ni ol en sis li th ra ph id ite s q ua dr at us si ra dn er ia cr en ul al a ce ra to lit ho id es k am pt ne ri cy cl ag el os ph ae ra a lta pr ed isc os ph ae ra s to ve ri m ic ul a m ur us ze ug rh ab do tu s p se ud an th op ho ru s ch ia st oz yg us a m ph ip on s th or ac os ph ae ra o pe rc ul at a cy cl ag el os ph ae ra re in ha rd tii bi sc ut um co ns ta ns th or ac os ph ae ra sa xe a br aa ru do sp ha er a bi ge lo w ii m ar ka liu s i nv er su s pl ac oz yg us si gm oi de s th an et ia n ta ra w an 45 f g n p7 /8 p4                                               vr             44 f g                                               vr             43 c g                                               vr           r se la nd ia n d a k h l a 42 r m np6                                               vr             41 f g n p5                                               vr           vr 40 f g                                               vr           vr 39 b n p4 n tp 8 p3 b                                                             38 f m                                               r           vr 37 f m                                               f           r 36 f m                                               vr           vr d an ia n 35 f m                                               vr           r 34 f m                                               vr         vr r 33 c g p3 a     vr                                         r           f 32 c g n tp 7     vr                                         r           f 31 a g     vr                                         r           f 30 a g                                               r           f 29 c g p2                                               vr           r 28 f m                                               vr           vr 27 c g   vr vr                                         vr           r 26 f m                                               r           vr 25 c g     vr                                         r       vr   r 24 c g                                               r             23 a g   vr vr                                         r           r 22 r m                                               f           vr 21 b                                                             20 f m   vr                                           vr vr         r 19 c m     vr                                         r           r 18 c m vr vr vr                                         f vr         r 17 c m                                               vr vr         r 16 f m         vr                                     vr           vr 15 f m vr vr vr                                         vr           vr 14 f m n tp 6 vr vr vr vr                                   vr   vr vr       vr vr 13 c m vr vr vr                                         vr vr         vr 12 c m vr vr vr vr vr                                 vr   vr     vr     vr 11 c m                                               vr vr   vr       10 c m vr vr vr                                         vr             9 f m vr vr vr vr   vr                               vr vr f r         r 8 c m np3 p1 c vr vr vr vr vr vr           vr vr     vr vr   vr       vr r r vr vr     r 7 c m r vr vr vr vr   vr vr   vr   vr         vr         vr vr vr vr vr       r 6 f m cc 26 c cf 2 vr vr vr vr vr vr vr   vr vr vr vr       vr vr         vr   vr vr vr   r vr vr la te st m aa s. su dr 5 f m f r           vr     vr vr     vr                 r vr vr vr       4 c m f r vr vr vr         vr         vr vr               r vr vr vr       3 c m r r r r r r vr vr vr vr     vr vr vr vr   vr vr vr   vr r r vr vr   r     2 f m f r r vr vr       vr       vr         vr vr vr r     r vr vr   r     1 c m c f r r r r vr vr vr vr vr vr vr vr vr vr vr vr vr vr r     r vr vr vr       faris and farouk: integrated biostratigraphy of two upper maastrichtian – palaeocene successions in north-central sinai, egypt geologia croatica 149 ta bl e 1: c on tin ue incoming paleocene taxa c ru ci pl ac ol ith us e dw ar ds ii n eo ch ia st oz yg us im br ie i cr uc ip la co lit hu s t en ui s er ic so ni a ca va er ic so ni a su bp er tu sa ch ia sm ol ith us d an ic us n eo ch ia st oz yg us e os ae pe s co cc ol ith us p el ag ic us el lip so lit hu s m ac el lu s ch ia sm ol ith us d an ic us sp he no lit hu s p rim us ch ia sm ol ith us e de nt ul us to w ei us to va e el lip so lit hu s d ist ic hu s cr uc ip la co lit hu s s ub ro tu nd us n eo ch ia st oz yg us m od es tu s cr uc ip la co lit hu s s ub ro tu nd us fa sc ic ul ith us p ile at us fa sc ic ul ith us ja ni i fa sc ic ul ith us in vo lu tu s fa sc ic ul ith us b ite ct us fa sc ic ul ith us b ill ii er ic so ni a un iv er sa to w ei us e m in en s n eo ch ia st oz yg us p er fe ct us fa sc ic ul ith us u lii fa sc ic ul ith us b ob ii bo m ol ith us co ni cu s el lip so lit hu s d ist ic hu s fa sc ic ul ith us ty m pa ni fo rm is fa sc ic ul ith us li lli an ae ch ia sm ol ith us ca lif or ni cu s fa sc ic ul ith us cl in at us h el io lit hu s c an ta br ia e h el io lit hu s k le in pe lli i fa sc ic ul ith us sc ha ub ii d isc oa st er m oh le ri fa sc ic ul ith us ri ch ar di i fa sc ic ul ith us a la ni i       r       r   v r f   r         v r   f     vr r     f     f     r     vr vr   vr       f r     f   v r f   v r           vr r             r     f         vr   vr           f f     f     r   v r           vr f     r vr r vr r     f           vr vr vr         vr vr     vr     r             v r   r     v r             r       vr r               f       r     f v r             v r r   r r vr   vr vr vr   f   r vr vr               v r   r     r   v r f v r v r         f f f   vr r r vr r vr vr vr f vr                                                                                                     f f     r vr vr r vr vr     vr vr r r r r vr     r r vr                             vr r       r vr vr f r       r r           r   f                                   r r     r   r f vr vr     r vr f f r f f f r vr f                               r f r     r vr r f vr       r                 r                                   r f     r   r vr         r             f r                                   r f c     r vr vr vr vr   vr   r             f r                                   r f c     r   f   vr vr     r             f                                     r f c     f   f           vr r           f                                     r f c     f vr f     vr     vr r vr   vr     r                                     r f c     f   r   vr       vr r     vr                                           r f r     f   vr   vr       vr                                                   r f f     f   r   vr vr     vr                                                     f f     f       r vr                                                         vr f r     f   r   r vr     vr vr vr   vr                                             f r     r vr   r r vr vr     r f f f r r                                       r f r     r   vr   r       r vr                                                   r r     r       r                                                                                                                                           f f     r   vr vr                                                             c f f     r vr vr r   vr   vr                                                     r f r     r   vr   vr                                                           f r r     r   vr   vr   vr                                                       r r r     r   vr r vr vr                                                         r r r     r   r                                                             vr r r   vr vr vr   vr r                                                           vr   f f vr vr r vr vr                                                               f f f     r   r                                                           r vr c f   vr   r vr vr r                                                       r vr c f   vr vr f vr r r                                                         r vr f f r vr vr r vr f                                                           vr vr f f r   vr f                                                                 vr r r r vr vr                                                                 vr                                                                                                                                                                                                                                                                                                                                                                                                     a bu nd an ce pr es er va tio n a : a bu nd an t g : g oo d c: c om m on m : m od er at e f: f re qu an t p: p oo r r: r ar e vr : v er y ra re * m ar ke r s pe ci es geologia croatica 65/2geologia croatica 150 ta bl e2 : st ra tig ra ph ic d is tr ib ut io n of th e id en tifi e d c al ca re ou s n an no fo ss ils in g eb el u m m k hu sh ay b se ct io n ag e fo rm at io n sa m pl e n o. a bu nd an ce pr es er va ti on n an no fo ss il zo ne cretaceous taxa survivors lu ci an or ha bd us ca ye ux ii m ic ro rh ab du lu s d ec or at us ch ia st oz yg us li tt er ar iu s w at zn au er ia b ar an es ae pr ed isc os ph ae ra cr et ac ea ei ff e lli th us g or ka e ah m ue lle re lla o ct or ad ia ta ar kh an ge lsk ie lla cy m bi fo rm is m ic ul a m ur us * cr ib ro sp ha er el la e hr en be rg ii ze ug rh ab do tu s p se ud an th op ho rt us m ic ul a de cu ss at a m ic ul a pr in sii te tra po do rh ab du s d ec or us ei ff e lli th us tu rr isi ef eu ii zy go lit hu s c ru x st ra dn er ia cr en ul at a ei ff e lli th us p ar al le lu s li th ra ph id ite s q ua dr at us m an iv ite lla p em m at oi de a th or ac os ph ae ra o pe rc ul at a pl ac oz yg us si gm oi de s cy cl ag el os ph ae ra re in ha rd tii th or ac os ph ae ra sa xe a m ar ka liu s i nv er su s br aa ru do sp ha er a bi ge lo w ii se la nd ia n be id a 251 c g n p6 p4                                         f           250 c m                                         f r         249 r m n p5                                           r         248 c m                                         f r         247 f g                                           r         246 c m                                           f         245 c g                                           f         244 f m n p4 n tp 8 p3 b                                                     243 c g                                         r       r   242 c g                                         r r         d an ia n 241 c m                                         r r         240 c m                                         r r         239 b n tp 7 p3 a                                                 r   238 c m               r                           r         237 f m               r       r                   r       r 236 f g p2                                         r r       v r 235 a g                                         r r       v r 234 c g n tp 6                                         r f     r   233 r m                                         r r         232 f m       r                                 r           231 f m               r       r                 r r         230 c m                       v r                 r   f       229 c m p1 c               v r       v r                 f f f       228 a m               v r       v r     r   r       f   f       227 r m n p3               v r   r   v r                 f   r       226 r p   r   r                                 f           225 c g       r       v r   r   r                 f f     r   224 f g p1 b r   r f       v r   r r r                 f f         223 r m r     r r     r r     r r               r r         222 f m r r   r r     r   r   f               r r r         m aa s. su dr 221 c m cc 26 c cf 2 r f r f r r   r r r   f   r r r r r r r r r       vr 220 c m r r r f r r r r r r r f r r r           r r r r r vr faris and farouk: integrated biostratigraphy of two upper maastrichtian – palaeocene successions in north-central sinai, egypt geologia croatica 151 ta bl e 2: c on tin ue incoming paleocene taxa n eo ch ia st oz yg us p er fe ct us cr uc ip la co lit hu s t en ui s* ch ia sm ol ith us d an ic us * cr uc ip la co lit hu s p rim us co cc ol ith us p el ag ic us er ic so ni a su bp er tu sa cr uc ip la co lit hu s e dw ar ds ii n eo ch ia st oz yg us m od es tu s n eo ch ia st oz yg us im br ie i n eo ch ia st oz yg us e os ae pe s el lip so lit hu s m ac el lu s sp he no lit hu s p rim us ch ia sm ol ith us e de nt ul us fa sc ic ul ith us b ite ct us fa sc ic ul ith us p ile at us er ic so ni a un iv er sa n eo ch ia st oz yg us ju nc tu s fa sc ic ul ith us p ile at us er ic so ni a un iv er sa fa sc ic ul ith us b ob ii fa sc ic ul ith us ty m pa ni fo rm is* ch ia sm ol ith us co ns ue tu s ch ia sm ol ith us b id en s to w ei us e m in en s h el io lit hu s c an ta br ia e bo m ol ith us co ni cu s h el io lit hu s k le in pe lli i fa sc ic ul ith us a la ni i d isc oa st er b ra m le tt ei r   r   f r           f       r r     r r     r     r r r r         f           f       f r r   r f     f   f r r r r       r                         r           r r         r   f   f f           r           r     r r r f           r       f             f       f   r   r f f   f           r   r   f     r     r f       r r r   r r r r             r   f   f f         r f       r   r   f r r               r     f r     r       r     r                             r r r   f f   r         r r f r   r r r                   r       f     r       f   f f   r f r f                       f   f             r r   r f                             r r   r f   r       r   r                                                       r                                     r   r r   r                                               r   r f             r                                   r r r r r         r                                       r r   f c           r                                     r r r f f     vr vr                                               f f   r r r r                                             f f     r r                                         r r r f f     r r                                           r   f r r r r   r r                                     r r   f f r r r                                           f r r f f r   r r r                                       r   r r r                                                       r r                                                 f r r r f r                                               f   f f f   r                                               r       r                                               v r r v r v r r r                                                                                                                                                                 a bu nd an ce pr es er va tio n a : a bu nd an t g : g oo d c: c om m on m : m od er at e f: f re qu an t p: p oo r r: r ar e vr : v er y ra re * m ar ke r s pe ci es geologia croatica 65/2geologia croatica 152 zo ne of romein (1979), and the cp4 zone of okada & bukry (1980), faris & abu shama (2007) and faris & salem (2007). 4.1.5. heliolithus kleinpellii zone (np6) defi nition: the fo of heliolithus kleinpellii defi nes the base of zone np6 and the fo of discoaster mohleri bukry & percival defi nes its top. occurrence: zone np6 occupies the interval from the upper part of the dakhla and bedia formations and is represented by samples 250–251 (2.5 m thick) in the umm khushayb section and occurs only in sample 42 (0.4 m thick) in the west el-hassana section. characteristic species: in addition to the fl oral assemblage, which characterizes zone np5, the following species are recorded in this zone: heliolithus kleinpellii, fasciculithus alanii perch-nielsen, discoaster bramlettei martini, and bomolithus conicus (perchnielsen). remarks: the fo of heliolithus cantabriae perchnielsen predates the fo of h. kleinpellii in the umm khushayb and west el-hassana sections, and occurs at the top of zone np5, in agreement with the observations of perch-nielsen (1985b) and tantawy et al. (2003). in the umm khushayb section, discoaster bramlettei occurs at the base of zone np6 and is considered here to be a reliable marker for the base of zone np6 in this section. 4.1.6. discoaster mohleri zone (np7/8) defi nition: the fo of discoaster mohleri bukry & percival is used to defi ne the base of zone np7/8 and the appearance of discoaster multiradiatus bramlette & reidel delineates its top. occurrence: this zone is only represented by the tarawan formation in the west el-hassana section (samples 43– 45, 1m thick). characteristic species: in addition to the identifi ed nannofossils that have been recorded in the zone np6; discoaster mohleri, fasciculithus schaubii hay & mohler, and f. richardii perch-nielsen have their fi rst appearance in this zone. remarks: the zonal scheme of martini (1971) cannot be applied to this interval because the marker species which defi nes the np7/np8 zonal boundary (heliolithus riedelii bramlette & sullivan) is absent in the west el-hassana section. the discoaster mohleri zone of romein (1979) is used here. in the umm khushayb section, the fo of fasciculithus alanii perch-nielsen occurs at the base of zone np6, while this species fi rst appears at the base of zone np7/8 in the west el-hassana section. the recorded zone np7/8 is equivalent to the combined np7 and np8 zones of martini (1971), the combined cp6 and cp7 zones of okada & bukry (1980), and to the np7/8 zone of faris & abu shama (2007) and faris & salem (2007). 4.2. planktonic foraminifera 4.2.1. pseudoguembelina palpebra partial range zone (cf2) defi nition: this zone is defi ned as the biostratigraphic interval from the last occurrence (lo) of gansserina gansseri (bolli) to the fi rst occurrence (fo) of plummerita hantkeninoides (brönnimann). occurrence: this zone occupies the upper part of the sudr formation in the study area. it’s true thickness is not defi ned because the base of the sudr formation is unexposed in the two studied sections. characteristic species. the most dominant planktonic species recorded in this zone yields a relative high abundance of biserial heterohelicids, while pseudoguembelinids, triserial and globotruncanid species are generally very rare (tables 3 & 4). remarks: the micula prinsii subzone coincides with part of the pseudoguembelina palpebra and the whole plummerita hantkeninoides zones (tantawy & keller, 2000; keller et al., 2007; farouk & faris, 2008). the absence of plummerita hantkeninoides and gansserina gansseri zones; in addition to the recognition of micula prinsii confi rms the presence of the cf2 in the upper part of the sudr formation (fig. 3). 4.2.2. eoglobigerina edita partial-range zone defi nition: this zone is defi ned as the biostratigraphic interval between the lo of parvularugoglobigerina eugubina (luterbacher & premoli silva) and the fo of praemurica uncinata (bolli). remarks: berggren & pearson (2005) subdivided the eoglobigerina edita (p1) zone from older to younger into the: 1) parasubbotina pseudobulloides (p1a), 2) subbotina triloculinoides (p1b) and 3) globanomalina compressa/praemurica inconstans (p1c) subzones. in the present study, the p1b subzone occurs directly on the maastrichtian (cf2 zone) (fig. 3). subbotina triloculinoides lowest-occurrence subzone (p1b) defi nition: this subzone represents the biostratigraphic interval from the fo of subbotina triloculinoides (plummer) to the fo of globanomalina compressa (plummer) and/or praemurica inconstans (subbotina). occurrence: the zone is recorded from the basal part of the beida formation and only from the gebel umm khushayb section. it is represented by samples 222–224 (0.5 m thick). this subzone is missing in the west el-hassana section due to the larger amplitude of the unconformity in this section. characteristic species. characteristic taxa are frequent, moderately well preserved and include globoconusa daubjergensis (brönnimann), globanomalina archeocompressa (blow), parasubbotina pseudobulloides (plumfaris and farouk: integrated biostratigraphy of two upper maastrichtian – palaeocene successions in north-central sinai, egypt geologia croatica 153 mer), parasubbotina trivalis (subbotina), subbotina triloculinoides, praemurica pseudoinconstans (blow), chi loguembelina midwayensis (cushman) and ch. morsei (kline) (tables 3 & 4). remarks: at the k/pg boundary, several changes are observed in the planktonic foraminiferal assemblages, including the extinction of virtually all cretaceous species (tropical-subtropical and cosmopolitan), and the fi rst appearance of the danian species. the cretaceous species present at the base of a transgression of lower danian sediments are reworked, and are represented by small cosmopolitan surface water dwellers such as heterohelix and pseudoguembelina with very rare rugoglobigerina and globotruncana spp.. the fos of globanomalina compressa and/or praemurica inconstans have been used to determine the base of subzone p1c (olsson et al., 1999; berggren & pearson, 2005). the authors believe that the fo of glo ba no malina compressa predates that of the fo of praemurica inconstans, and occurs within zone p1b. a similar occurrence in subzone p1b was also reported by keller (2002). according to berggren & pearson (2005), zone p1b falls between the top part of the cruciplacolithus tenuis (np2) zone, and the basal part of the chiasmolithus danicus (np3) zone. therefore, the authors believe that the base of zone p1b should be absent in the gebel umm khushayb due to absences of the cruciplacolithus tenuis zone np2. globanomalina compressa/praemurica inconstans lowest-occurrence subzone (p1c) defi nition: the biostratigraphic interval from the fo of globanomalina compressa and/or praemurica inconstans and the fo of praemurica uncinata. occurrence: this zone is recorded from the lower part of the dakhla formation and represented only by samples 7–8 (2.0 m thick) from the west el-hassana section and it encompasses, samples 224–230 (3.0 m thick) at the gebel umm khushayb section. characteristic species. in this interval the species are highly abundant and well preserved. the assemblage of this interval is similar to that of the underlying subzone p1c with the addition of four more species praemurica inconstans, globanomalina compressa and parasubbotina varianta (subbotina), morozovella trinidadensis (bolli). remarks: keller (2002) subdivided subzone p1c into two subzones, p1c (1) and p1c (2) based on the fi rst appearance of praemurica inconstans. in the present study, the fos of praemurica inconstans, globanomalina compressa figure 3: standard and alternative planktonic foraminiferal and calcareous nannofossil biozonations for the palaeocene interval. geologia croatica 65/2geologia croatica 154 table 3: stratigraphic distribution of planktonic foraminiferal taxa identifi ed in the west el-hassana section. ag e fo rm at io n sa m pl e n o. n an no fo ss il zo ne pl an kt on ic fo ra m . z on e g lo bo tr un ca na a eg yp tia ca g lo bo tr un ca na ro se tt a ru go gl ob ig er in a he xa ca m er at a ru go gl ob ig er in a m ac ro ce ph al a ru go gl ob ig er in a ru go sa h et er oh el ix g lo bu lo sa h et er oh el ix d en ta ta h et er oh el ix n av ar ro en sis h et er oh el ix st ria ta ps eu do gu em be lin a ha ria en sis ps eu do gu em be lin a co st ul at a ps eu do te xt ul ar ia e le ga ns g lo bo tr un ca ne lla su bc ar in at us . su bb ot in a tr ilo cu lin oi se s* su bb ot in a tr iv ia lis su bb ot in a tr ia ng ul ar is su bb ot in a co nc el la ta su bb ot in a ve la sc oe ns is pa ra su bb ot in a ps eu do bu llo id es pa ra su bb ot in a va ria nt a pa ra su bb ot in a va rio sp ira pr ae m ur ic a in co ns ta ns * pr ae m ur ic a un ci na ta * g lo ba no m al in a co m pr es sa g lo ba no m al in a eh re nb er gi g lo ba no m al in a ps eu do m en ar di i* ch ilo gu em be lin a m id w ay en sis ch ilo gu em be lin a m or se i ig or in a pu sil la ig or in a al be ar i* m or oz ov el la p ra ea ng ul at a m or oz ov el la a ng ul at a* m or oz ov el la co ni co tr un ca ta m or oz ov el la a pa nt he sm a m or oz ov el la p as io ne ns is m or oz ov el la v el as co en sis * m or oz ov el la a cu ta m or oz ov el la p re ae qu a m or oz ov el la a eq ua m or oz ov el la o cc lu sa ac ar in in a st ra bo ce lla ac ar in in a m ck an na i th an et ia n ta ra w an 45 n p7 /8 p4 b   r r r r r r r r 44   f r r f r r r r 43   f r r f r r r r se la nd ia n d a k h l a 42 np6 p4 a   c r r r f r r r r 41 n p5   f r r r f r r r   40   c r r r r r r r r   39 n p4 n tp 8 p3 b   r   38   r r r vr r r r   37   r r r r   36   r r r r r r r r   d a n i a n 35   r r r r r r r f c r r r r   34   r r r r r a r r r   33 p3 a   r r c r a r   32 n tp 7   c r r c c r a   31   a r r r c r r r a   30   a r r c a r c r f a   29 p2   a r r a r a c   28   c r r r c c a r c   27   c r c c c a r r   26   a r c f c a r r   25   a r c f c a r   24   c r c f c a r   23   c c f c a r   22   c c r c a r   21     20   c a f r c r r   19   c a r r c r r   18   c a f f c r r   17   r a f f a f r   16   r r a f f a f r   15   c r a c f c c r   14 n tp 6   c a c c c c   13   c a c c c c   12   c a a c r r   11 c a a c   10 c r r a c c c vr   9 r r r r a c f r vr   8 np3 p1 c r r r c r a f r r vr   7 r r r r f r a f r r vr   la te st m aa s. su dr 6 m . p rin si cf 2 a f c r       5 a f r c r f vr     4 vr vr a f r c f               3 vr vr vr vr r a f vr c r c f r   2 a f vr c r   1 r   r r r a f vr c   r vr                                                             a= abundant c= common f= frequent vr= very rare r= rare r=reworked *marker species faris and farouk: integrated biostratigraphy of two upper maastrichtian – palaeocene successions in north-central sinai, egypt geologia croatica 155 table 4: stratigraphic distribution of planktonic foraminiferal taxa identifi ed in the gebel umm khushayb section. ag e fo rm at io n sa m pl e n o. n an no fo ss il zo ne pl an kt on ic fo ra m . z on e g lo bo tr un ca na a eg yp tia ca ru go gl ob ig er in a he xa ca m er at a ru go gl ob ig er in a m ac ro ce ph al a ru go gl ob ig er in a ru go sa h et er oh el ix g lo bu lo sa h et er oh el ix la be llo sa h et er oh el ix n av ar ro en sis h et er oh el ix st ria ta ps eu do gu em be lin a ha ria en sis ps eu do gu em be lin a pa lp eb ra ps eu do gu em be lin a co st ul at a ps eu do te xt ul ar ia e le ga ns g lo bo tr un ca ne lla su bc ar in at us su bb ot in a tr ilo cu lin oi se s su bb ot in a tr iv ia lis su bb ot in a tr ia ng ul ar is su bb ot in a ve la sc oe ns is pa ra su bb ot in a ps eu do bu llo id es pa ra su bb ot in a va ria nt a pa ra su bb ot in a va rio sp ira pr ae m ur ic a in co ns ta ns * pr ae m ur ic a un ci na ta * g lo ba no m al in a ar ch eo co m pr es sa g lo ba no m al in a co m pr es sa * g lo ba no m al in a eh re nb er gi g lo ba no m al in a ps eu do m en ar di i* ch ilo gu em be lin a m id w ay en sis ch ilo gu em be lin a m or se i ig or in a pu sil la ig or in a al be ar i* m or oz ov el la p ra ea ng ul at a m or oz ov el la a ng ul at a* m or oz ov el la co ni co tr un ca ta m or oz ov el la a pa nt he sm a m or oz ov el la v el as co en sis * m or oz ov el la a cu ta m or oz ov el la p re ae qu a m or oz ov el la a eq ua m or oz ov el la o cc lu sa ac ar in in a st ra bo ce lla ac ar in in a m ck an na i se la nd ia n b e i d a 251 n p6 p4 a r r r r r r r r r r 250 r r r r r r r r 249 n p5 r r r r r r r r r r 248 r r r r r r r r   247 r r r r r r   246 f r r r c f a r c r   245 r r r r r r r r r   244 n p4 n tp 8 r r f r f r r   243 p3 b r r r vr r r r r r r r   242 c r vr a r r   d a n i a n 241 c r vr a f f r   240 r r c r f vr r a c r   239 n tp 7 p3 a   238 r f r r vr r f   237 c vr r r r f f r c   236 p2 r a r   235 c c r   234 n tp 6 c f   233 c f   232 c f   231 c f       230 a vr a c f f     229 p1 c r r a c f c a   228 c r f c r f     227 n p3 c c f c r f   226 f r c c c c   225 f r a f f c vr   224 p1 b r r a f r vr vr   223 c vr a f r   222 r r r vr a f r   m aa s. su dr 221 c c 26 cf 2 vr vr f f a r r a vr r r r vr   220   r f f a c r a vr r r c vr                                                         a = abundant c = common f = frequent vr = very rare r = rare r = reworked *marker species and parasubbotina varianta occur directly above zone cf2 in the west el-hassana section, indicating that the oldest danian sediments belong to the p1c (2) subzone. 4.2.3. praemurica uncinata lowest-occurrence zone (p2) defi nition: this is the biostratigraphic interval between the fo of praemurica uncinata to the fo of morozovella angulata (white). occurrence: the zone encompasses the middle part of the dakhla formation at the west el-hassana section and is represented by samples 9–29 (15 m thick). in the gebel umm khushayb section it is recorded from the middle part of the beida formation and is represented by samples 229–236 (8 m thick). characteristic species. the praemurica uncinata zone is rich in its faunal content. the most dominant planktonic species recorded in this zone include: globanomalina comgeologia croatica 65/2geologia croatica 156 characteristic species. morozovella angulata, m. conicotruncata, parasubbotina varianta, m. velascoensis (cushman), m. occlusa (loeblich & tappan), m. acuta (toulmin), m. aequa (cushman & renz), subbotina velascoensis (cushman), subbotina triloculinoides igorina albeari and i. pusillla (bolli) are the dominant planktonic species in the p 3 b subzone. remarks. morozovella conicotruncata and m. pasionensis fi rst appeared within the lower part of this subzone, while m. velascoensis, m. occlusa, m. acuta, m. preaequa and subbotina velascoensis fi rst occurred within the upper part of the subzone (tables 3 & 4). 4.2.5. globanomalina pseudomenardii total range zone (p4) defi nition: this zone is defi ned as the interval of the total range of the nominated taxon. occurrence: the zone occupies about 5.5 m of the uppermost part of the measured beida formation at gebel umm khushayb and is represented by samples 244–251. it also occurs in the topmost part of the dakhla formation, as well as the whole tarawan formation at the west el-hassana section (samples 40–45). characteristic species. the dominant species in this subzone include angular morozovellids such as morozovella acuta, m. aequa, m. velascoensis, m. occlusa, acarinina mckannai (white), a. strabocella (loeblich & tappan) and subbotina velascoensis. remarks. berggren and pearson (2005) subdivided the p4 zone into three subzones; globanomalina pseudomenardii/parasubbotina variospira (p4a) concurrentrange subzone; acarinina subsphaerica (p4b) partial-range subzone and acarinina soldadoensis/globanomalina pseudomenardii (p4c) concurrent-range subzone. in the current study, it was also diffi cult to subdivide the p4 into these biozones due to the poor preservation of foraminiferal tests as a result of carbonate dissolution. olsson et al. (1999) reported that the fo of morozovella aequa occurs at the lower boundary of the p4c zone. in the present study, the fo of morozovella aequa is recognized at the top part of p3b zone, which is equivalent to the top part of the calcareous nannofossil np4 zone. a similar occurrence in the p3b zone was also reported by arenilas (2012) in the caravaca section of spain. 5. stage boundaries 5.1. the cretaceous/palaeogene (k/pg) boundary the k/pg boundary is marked by an abrupt lithological change that corresponds to the boundary between the sudr and dakhla formations at the west el-hassana section or to the sudr / beida formation at umm khushayb. biostratigraphic analysis (planktonic foraminifera, calcareous nannofossils) confi rms that the studied sections are incomplete and discontinuous across the k/p boundary. a small hiatus is suggested by the absence of the plummerita hantkenipressa, parasubbotina pseudobulloides, parasubbotina varian ta, subbotina concellata (blow), s. trinagularis (whi te), s. triloculinoides, s. trivialis, praemurica uncinata, p. inconstans and morozovella praeangulata (blow) (tables 3 & 4). remarks: subbotina triangularis and s. concellata fi rst appear within the upper part of this biozone (tables 3 & 4). steurbaut & sztrákos (2008), mentioned that the praemurica uncinata zone falls within the top part of the calcareous nannofossil zone ntp6 in south-west france. in the present study, it falls within zone ntp6 and the lower part of zone ntp7. a similar occurrence was also reported by steurbaut et al. (2000) in the kalaat senan section, central tunisia. 4.2.4. morozovella angulata-globanomalina pseudomenardii interval zone (p3) defi nition: this includes the interval from the fo of morozovella angulata to the fo of globanomalina pseudomenardii (bolli). occurrence: the biozone is represented by samples 30– 39 (4.5 m thick) in west el-hassana, and sample 237–243 (7 m thick) from gebel umm khushayb. various authors have observed that zone p3 is condensed in this area (e.g. samir, 2002; al-wosabi & abu shama, 2007 in egypt; van itterbeek et al., 2007 in tunisia). remarks: berggren et al. (1995), berggren & norris (1997) and olsson et al. (1999) re-subdivided p3 zone into two subzones: the morozovella angulata-igorina albeari interval subzone (p3a) and the igorina albeari– globanomalina pseudomenardii interval subzone (p3b). in the present study the p3 zone can also be divided into two subzones. morozovella angulata-igorina albeari interval subzone (p3a) defi nition: interval from the fo of the morozovella angulata to the fo of igorina albeari (cushman & bermudez). characteristic species. the planktonic assemblage of this subzone is dominated by morozovellids with angular conical chambers throughout their youngest whorl, such as morozovella conicotruncata (subbotina), m. praeangulata, m. angulata (white), and m. praecursoria (morozo va). in addition, other taxa are also present: subbotina triloculinoides, globanomalina compressa, igorina pusilla and praemurica uncinata (tables 3 & 4). remarks: globanomalina compressa, praemurica uncinata, and p. inconstans disappeared in the lower part of this subzone. igorina albeari/globanomalina pseudomenardii interval subzone (p3b) defi nition: this represents the interval between the fo of igorina albeari and the fo of globanomalina pseudomenardii (bolli). faris and farouk: integrated biostratigraphy of two upper maastrichtian – palaeocene successions in north-central sinai, egypt geologia croatica 157 noides, guembelitria cretacea, parvularugoglobigerina eugubina zones and parasubbotina pseudobulloides subzone. in the west el-hassana section, the subbotina triloculinoides subzone is also missing. moreover, the upper part of the calcareous nannofossil micula prinsii subzone and the earliest danian zones (np1 and np2) are missing. this hiatus may be linked to tectonic activity and irregular palaeotopography associated with low sedimentation rates as suggested by farouk & faris (2008). the k/pg boundary is characterized by the extinction of cretaceous tropical planktonic foraminifera, and an abrupt change in species richness. however, most of the cretaceous calcareous nannofossil vanishing species progressively decrease in abundance within zone np4; only the most dissolution-resistant cretaceous species (micula decussata, watznaueria barnesae) are still present near the top of zone np4. the cretaceous persistent species progressively increase in abundance above the k/pg boundary. cyclagelosphaera reinhardtii is the most common cretaceous persistent species in the palaeocene. 5.2. the danian/selandian boundary the global stratotype section and point (gssp) across the danian/selandian (da/se) boundary has been defi ned in the zumaia section, northern spain close to the fo of f. tympaniformis, just below the np4/np5 boundary and within the planktonic foraminiferal p3b zone (bernoala et al., 2009). based on calcareous nannofossils, the danian/selandian (da/se) boundary is delineated at a level close to the fo of fasciculithus tympaniformis, just below the np4/np5 boundary and it coincides with the end acme of braarudosphaera bigelowii (bernoala et al., 2009). the lowest common occurrence (lco) of braarudosphaera, which marked the lithological change at the d/s boundary at the type area in denmark, can be directly correlated with the abrupt transition from the danian limestones to the marly itzurun fm. at zumaia (schmitz et al., 1998; bernaola et al., 2009). this event is not applicable to the tethyan sections because braarudosphaera was not recorded there (ber naola et al., 2009). the last common occurrence (lco) of braarudosphaera seems applicable for placing the base of the selandian in denmark, but it is an unreliable event for de lineating the danian/selandian boundary in the study sections. previously in egypt, the danian/selandian was marked as a prominent organic-rich layer with a short-term sea-level fall coinciding with the p3a/p3b boundary, by using the lowest occurrence of the slightly keeled igorina as a zonal boundary criterion (speijer, 2003; obaidalla et al., 2009; sprong et al., 2009). in the qreiya section, the organicrich layer occurs approximately 1 m above the fos of chiasmolithus edentulus and small fasciculiths (sprong et al., 2009). this event bed at the d/s boundary, situated at the base of the subzone ntp7b, and the equivalent planktonic foraminiferal p3a/p3b zonal boundary, is now considered latest danian in age (bernoala et al., 2009; youssef, 2009). on the other hand, faris & abu shama (2007) put the danian/selandian boundary at the base of zone np5. in the present study, it is bracketed within the zone ntp8 (topmost np4 equivalent to top part of the planktonic foraminifera p3b subzone), at a level close to the first occurrence (fo) of morozovella velascoensis, m. occulsa, m. aquea and m. acuta (below) and the fo of fasciculithus tympaniformis (above) just below the np4/np5 boundary in west el-hassana and umm khushayb sections, is similar to that of the global standard stratotype-section and point (gssp) of the da/se boundary which has recently been selected at the zumaia section. an important global nannofossil event is the onset of the second radiation of fasciculithus (f. bitectus, f. involutus, f. janii, f. billii and f. ulii). it starts within zone ntp8 (topmost np4 and p3b) at a level close to the fo of f. tympaniformis and just below the np4/np5 boundary in the study sections. the fi rst continuous occurrence (fco) of sphenolithus primus, the marker taxon for the base of subzone ntp8a of varol (1989), is a reliable marker for delineating the danian/selandian transition (faris et al., 2005, quillevere et al., 2002). in the present study, the fro (first rare occurrence) of sphenolithus primus is not a useful global marker because it occurs rarely and sporadically. steurbaut & sztrákos (2008) and bernaola et al. (2009) also reported a similar occurrence for the fro of sphenolithus primus. 5.3. the selandian/thanetian boundary the base of the thanetian in its original type area, has been correlated within the upper part of the nannofossil zone np6 (aubry, 1994; knox, 1994). the base of chron c26n at zumaian, as a continuous, deep marine and cyclic sequence, offers the possibility of establishing a potential thanetian unit stratotype (dinarès-turell et al., 2007). it is positioned 30.5 m above the base of the itzrun formation, very close to the base of chron c26n (schmitz et al., 1998). a minor hiatus is proposed at the selandian/thanetian boundary as indicated by a condensed interval that marks a lithological change from the calcareous shales of the dakhla formation to the limestones of the tarawan formation. therefore, the selandian/thanetian boundary in the present study is located at the top of zone np6 and within the lower part of the globanomalina pseudomenardii zone. no great changes in the nannofossil assemblages have been observed in the west el hassana section, except for the fo of discoaster mohleri. the heliolithus kleinpellii zone (np6) is not recorded in several localities in egypt (e.g. bassiouni et al., 1991; faris et al., 1999; faris & zahran, 2002; ayyad et al., 2003). 6. conclusions the results obtained can be summarized as follows: 1. an integrated calcareous nannofossil and planktonic foraminiferal biostratigraphy has been achieved for the geologia croatica 65/2geologia croatica 158 upper maastrichtian-palaeocene successions on the west el-hassana and umm khushayb sections, northcentral sinai. the maastrichtian – palaeocene material studied in this work consists of siliciclastic/carbonate deposits belonging to four formations: the sudr, dakhla, tarawan formations, and their lateral coeval beida formation. 2. 44 calcareous nannofossil and 31 planktonic foraminiferal taxa are identifi ed with moderate to good preservation and relatively high diversity. these microfossil assemblages allowed subdivision of the study sections into one subzone and fi ve calcareous nannofossil zones: micula prinsii subzone (cc26c), chiasmolithus danicus zone (np3), ellipsolithus macellus zone (np4), fasciculithus tympaniformis zone (np5), heliolithus kleinpellii zone (np6), discoaster mohleri zone (np7/8); and fi ve planktonic foraminiferal zones and four subzones; pseudoguembelina palpebra zone (cf2), eoglobigerina edita (p1) zone, praemurica uncinata zone (p2), morozovella angulata-globanomalina pseudomenardii zone (p3), globanomalina pseudomenardii zone (p4). zone p1 can be subdivided into the subbotina triloculinoides subzone (p1b), and the globanomalina compressa/praemurica inconstans subzone (p1c). zone p3 is subdivided into the morozovella angulata-igorina albeari subzone (p3a), and the igorina albeari/globanomalina pseudomenardii subzone (p3b). 3. biostratographic analyses of the two studied sections based on planktonic foraminifera and calcareous nannofossils, indicate that deposition of the latest maastrichtian to early danian sediments was interrupted by erosion and or non-deposition related to tectonic activity. as a result, some planktonic foraminifera (plummerita hantkeninoides, guembelitria cretacea, parvularugoglobigerina eugubina biozones and, parasubbotina pseudobulloides subzone and their equivalent calcareous nannofossils (top part of cc26c, np1 and np2 zones) are missing. 4. the new-palaeocene calcareous nannfossil taxa fi rst appear at the base of zone np3 of early danian age. they progressively increase upwards and are more common than the cretaceous vanishing species in zone np3 and np4. 5. according to the palaeocene zonal scheme of varol (1989); the nannofossil zone np4 of martini (1971), can be divided into three subzones; ntp6, ntp7 and ntp8 in the west el-hassana and umm khushayb sections. a small hiatus is observed at the np3/np4 zonal boundary as suggested by the absence of the ntp5b subzone and ntp5c and most probably the lowermost part of zone ntp6. 6. the onset of a second diversifi cation of the genus fasciculithus, represented by f. bitectus, f. involutus, f. janii, f. billii and f. ulii, begins within zone ntp8 and just below the np4/np5 boundary in el hassana and umm khushayb sections. this radiation marks the danian/selandian boundary. based on planktonic fora minifera, the danian/selandian boundary lies with the basal part of the p3b subzone. 7. the selandian/thanetian boundary is placed at the contact between the dakhla and tarawan formations at west el-hassana, approximately at the top of calcareous nanofossil zone np6 within the equivalent planktonic foraminiferal zone p4. a minor hiatus was observed at this boundary as indicated by the prominent lithological chan ge from the calcareous shale of the dakhla formation to the limestones of the tarawan formation and the very condensed calcareous nannofossil zone np6. references allam, a. & khalil, h. (1988): geology and stratigraphy of the arif el-naqa area, sinai, egypt.– egypt. j. geol., 32, 199–218. alvarez, l.w., alvarez, w., asaro, f. & michel, h.v. (1984): the end of the cretaceous: sharp boundary or gradual transition.– science, 223, 1183–1186. doi:10.1126/science.223.4641.1183 alvarez, l.w., alvarez, w., asaro, f. & michel, h.v. (1980): extraterrestrial cause for the cretaceous-tertiary extinction: experimental results and theoretical interpretation.– science, 208, 1095–1108. al-wosabi, k. & abu shama, a.z. (2007): planktonic foraminiferal and calcareous nannofossil biostratigraphy around the k/p boundary at section, west central sinai, egypt.– egypt. j. paleont., 7, 87–115. arenillas, i. (2011): patterns of spatio-temporal distribution as criteria for the separation of planktic foraminiferal species across the danian-selandian transition in spain.– acta palaeont. polon., 57/2, 401–402. doi: http://dx.doi.org/10.4202/app.2010.0076 aubry, m.-p. (1994): the thanetian stage in nw europe and its signifi cance in terms of global events.– gff, 116, 43–44. awad, g.h. & ghobrial, m.g. (1966): zonal stratigraphy of the kharga oasis.– geological survey of egypt, cairo, paper, 34, 77 p. ayyad, s.n., faris, m., el nahass, h.a. & saad, k.a.a. (2003): planktonic foraminiferal and calcareous nannofossil biostratigraphy from the upper cretaceous-lower eocene successions in northeast sinai, egypt.– in: 3rd international conference on the geology of africa, assiut university, 1, 649–683. backman, j. (1986): late palaeocene to middle eocene calcareous nannofossil biochronologyfrom the shatsky rise, walvis ridge and italy.– palaeog., palaeocl., palaeoec., 57, 43–59. bassiouni, m.a., faris, m. & sharaby, s. (1991): late maastrichtian and palaeocene calcareous nannofossils from ain dabadib section, nw kharga oasis, egypt.– qatar univ. sci. j., 11, 357–375. berggren, w.a. & pearson, p.n. (2005): a revised tropical to sub tropical palaeogene planktonic foraminiferal zonation.– j. foram. res., 35, 279–314. doi:10.2113/35.4.279 berggren, w.a., aubry, m.-p., van fossen, m., kent, d.v., norris, r.d. & quillevere, f. (2000): integrated palaeocene calcareous plankton magnetobiochronology and stable isotope stratigraphy: dsdp site 384 (nw atlantic ocean).– palaeog., palaeocl., palaeoec., 159, 1–51. doi:10.1016/s0031-0182(00)00031-6 berggren, w.a., kent, d.v., swisher, c.c.i. & aubry, m.-p. (1995): a revised cenozoic geochronology and chronostratigraphy.– in: hardenbol, j. (ed.): geochronology, time scales and global stratigraphic correlation, society of economic paleontologists and mineralogists, special publication, 54, 129–212. berggren, w.a. & norris, r.d. (1997): biostratigraphy, phylogeny, and systematics of palaeocene planktic foraminifera.– micropaleontolgy, 43 (supplement 1), 1–116. doi:10.2307/1485988 faris and farouk: integrated biostratigraphy of two upper maastrichtian – palaeocene successions in north-central sinai, egypt geologia croatica 159 bernaola, g. & monechi, s. (2007): calcareous nannofossil extinction and survivorship across the cretaceous−palaeogene boundary at walvis ridge (odp hole 1262c, south atlantic ocean).– palaeog., palaeocl., palaeoec., 255, 132–156. bernaola, g., martin-rubio, m. & baceta, j.i. (2009): new high resolution calcareous nannofossil analysis across the danianselandian transition at the zumaia section: comparisons with south tethys and danish sections.– geol. acta, 7, 79–92. bolle, m.-p. & adatte, t. (2001): palaecoene-early eocene climatic evolution in the tethyan realm: clay mineral evidence.– clay min., 36, 249–261. clemen, w.a., archivald, j.d. & hickey, l.j. (1981): out with a whimper not a bang.– paleobiology, 7, 293–298. courtillot, v., feraud, g., maluski, h., vandamme, d., moreau, m.g. & besse, j. (1988): deccan fl ood basalts and the cretaceous/tertiary boundary.– nature, 333, 843–846. doi: 10.1038/333843a0 dinares-turell, j., baceta, j.i., bernaola, g., orueetxebarria, x. & pujalte, v. (2007): closing the mid-palaeocene gap: toward a complete astronomically tuned palaeocene epoch and selandian and thanetian gssps at zumaia (basque basin, w pyrenees).– earth plan. sci. lett., 262, 450–467. doi:10.1016/ j.epsl.2007.08.008 el-deeb, w.z., faris, m. & mandour, m.m. (2000): foraminiferal and calcareous nannofossil biostratigraphy of the palaeocene in north central sinai, egypt.– annals of the geological survey of egypt, 23, 103–118. el-nady, h. & shahin, a. (2001): planktonic foraminiferal biostatigraphy and palaeobathymetry of the late cretaceous-early tertia ry succession at northeast sinai, egypt.– egypt. j. paleont., 1, 193–227. faris, m. & zahran, e. (2002): calcareous nannofossil biostratigraphy of the late palaeocene/early eocene of el-bruk area, north central sinai.– egypt. j. paleont., 2, 359–369. faris, m., abd el-hameed, a.t., marzouk, a. & ghandour, i.m. (1999): early palaeogene calcareous nannofossil and planktonic foraminiferal biostratigraphy in central egypt.– n. jahrb. geol. paläont. abhandl., 213/2, 261–288. faris, m. & abu shama, a.m. (2007): nannofossil biostratigraphy of the palaeocene –eocene succession in the thamad area, east central sinai, egypt.– micropaleont., 1–2, 127–144. doi: 10.2113/ gsmicropal.53.1-2.127 faris, m., ayyad, s.n., el nahass, h.a., & al wosabi, kh.a. (2005): early palaeogene stages and their boundaries in sinai, egypt.– in: the fourth international conference on the geology of africa, assiut university, egypt, 2, 753–768. faris, m., el-deeb, w. & mandour, m. (2000): biostratigraphy of some upper cretaceous/lower eocene successions in north and southwest sinai, egypt.– annals of the geological survey of egypt, 23, 135–161. faris, m. & salem, r.f. (2007): palaeocene-early eocene calcareous nannofossil biostratigraphy in west central sinai, egypt.– in: proceedings of the 8th conference geology of sinai for development, ismailia, 1–14. farouk, s. & faris, m. (2008): campanian to eocene planktic foraminiferal and calcareous nannofossil biostratigraphy in the synclinal areas around gebel libni, north sinai, egypt.– earth sci. ser., 22, 187–201. gardan, s. (2002): late maastrichtian to early danian calcareous nannofossils at elles, northwest tunisia: a tale of one million years across the k-t boundary.– palaeog., palaeocl., palaeoec., 178, 211–231. doi:10.1016/s0031-0182(01)00397-2 ghorab, m.a. (1961): abnormal stratigraphic features in ras gharib oil fi eld.– in: 3rd arab petroleum congress, alexandria, egypt, p. 10. hallam, a. (1987): end-cretaceous mass extinction event: argument for terrestrial causation.– science, 238, 1237–1242. keller, g., adatte, t., tantawy, a.a., berner, z., stinnesbeck, w., stueben, d. & lenaza, h.a. (2007): high stress late maastrichtian early danian palaeoenvironment in the neuque´n basin, argentina.– cretac., res., 28, 939–960. keller, g. (2002): guembelitria-dominated late maastrichtian planktic foraminiferal assemblages mimic early danian in central egypt.– marine micropaleont., 47, 71–99. doi:10.1016/s03778398(02) 00116 -0 kennett, j.p. & stott, l.d. (1991): abrupt deep-sea warming, paleoceanographic changes and benthic extinction at the end of the palaeocene.– nature, 353, 225–229. knox, r.w. (1994): the age and regional context of the thanetian stratotype sections of the se england.– gff, 116, 55–56. doi:10.1038/ 353225a0 lamolda, m.a. & gorostidi, a. (1992): nannofossil stratigraphic record in the upper maastrichtian–lowermost danian at zumaya (northern spain).– in: proceedings of the 3rd international nannoplankton association conference. mem. sci. geol., 43, 149–161. lees, j.a. (2002): calcareous nannofossils biogeography illustrates palaeoclimate change in the late cretaceous indian ocean.– cretac. res., 23, 537–634. doi:10.1006/cres.2003.1021 li, l. & keller, g. (1998): maastrichtian climate, productivity and faunal turnovers in planktic foraminifera in south atlantic dsdp sites 525 and 21.– marine micropaleont., 33, 55–86. lüning, s., marzouk, a.m. & kuss, j. (1998): the palaeocene of central east sinai, egypt: ‘sequence stratigraphy' in monotonous hemipelagites.– j. foram. res., 28/1, 19–39. martini, e. (1971): standard tertiary and quaternary calcareous nannoplankton zonation. – in: farinacci, a. (ed.): proceedings of the second planktonic conference, edizioni tecnoscienza, rome, 2, 739–785. marzouk, a.m. & lüning, s. (1998): comparative biostratigraphy of calcareous nannofossils and planktonic foraminifera in the palaeocene of eastern sinai, egypt.– n. jahrb. geol. paläontol., abhandl., 207/1, 77–105. mclean, d.m. (1982): deccan volcanism and the cretaceous – tertiary transition scenario: a unifying causal mechanism.– syllogeus, 39, 143–144. mclean, d.m. (1985): deccan traps mantle degassing in the terminal cre taceous marine extinctions.– cretac. res., 6, 235–259. doi: 10.1016/0195 -6671(85)90048-5 monechi, s., bleil, u. & backman, j. (1985): magnetobiochronology of late cretaceous-palaeogene and late cenozoic pelagic sedimentary sequences from the northwest pacifi c (deep sea drilling project leg 86, site577).– in: initial reports of the deep sea drilling project, u.s. government printing offi ce, washington, 787–797. obaidalla, n.a., el-dawy, m.h. & kassab, a.s. (2009): biostratigraphy and paleoenvironment of the danian/selandian (d/s) transition in the southern tethys: a case study from north eastern desert, egypt.– j. afr. earth sci., 53, 1–15. doi:10.1016/j.jafrearsci.2008.07.004 okada, h. & bukry, d. (1980): supplementary modifi cation and introduction of code numbers to the low latitude coccolith biostratigraphic zonation (bukry, 1973, 1975).– marine micropaleont., 5, 321–325. doi:10.1016/0377-8398(80)90016-x olsson, r.k., hemleben, c., berggren, w.a. & huber, b.t. (1999): atlas of palaeocene planktonic foraminifera.– smithsonian contributions to paleobiology, 85, 1–252. orue-etxebarria, x., apellaniz, e. & caballero, f. (2007): discrepancies in planktic foraminifera biostratigraphies across the danian/selandian transition at zumaia: no poor presergeologia croatica 65/2geologia croatica 160 vation, but taxonomic different concepts.– in: abstracts of the international workshop of the palaeocene working group (zumaia, basque country), 25–27. perch-nielsen, k. (1985a): mesozoic calcareous nannofossils.– in: bolli, h. m., saunders, j. b. & perch-nielsen, k. (eds.): plankton stratigraphy, cambridge university press, 329–426. perch-nielsen, k. (1985b): cenozoic calcareous nannofossils.– in: bolli, h.m., saunders, j.b. & perch-nielsen, k. (eds.): plankton stratigraphy, cambridge university press, 427–554. pospichal, j.j. (1994): calcareous nannofossils at the k–t boundary, el kef: no evidence for stepwise, gradual, or sequential extinctions.– geology, 22, 99–102. doi:10.1130/0091-7613(1994)022< 0099:cnatkt>2.3.co;2 quillevere, f., aubry, m.-p., norris, r.d. & berggren, w.a. (2002): palaeocene oceanography of the eastern subtropical indian ocean: an integrated magnetostratigraphic and stable isotope study of odp hole 761b (wombat plateau).– palaeogeog., palaeoclim., palaeoec., 184/4, 371–405. romein, a.j.t. (1979): lineages in early palaeogene calcareous nannoplankton.– utrecht micropalaeont. bull., 22, 1–230. said, r. (1961): tectonic framework of egypt and its infl uence on distribution of foraminifera.– aapg bulletin, 45, 198–218. said, r. (1962): the geology of egypt.– elsevier publishing company, amsterdam, 370 p. samir, a. (2002): biostratigraphy and paleoenvironment changes in the upper cretaceous-early palaeogene deposits of gabal samra section, southwestern sinai, egypt.– egypt. j. paleont., 2, 1–40. schmitz, b., molina, e., von salis, k. (1998): the zumaya section in spain: a possible global stratotype section for the selandian and thanetian stages.– newsletters on stratigraphy, 36, 35–42. sissingh, w. (1977): biostratigraphy of cretaceous calcareous nannoplancton.– geologie en mijnbouw, 56, 37–65. speijer, r.p. (2003): danian–selandian sea-level change and biotic excursion on the southern tethyan margin (egypt).– in: wing, s. l., gingerich, p.d., schmitz, b. & thomas, e. (eds.): cau ses and consequences of globally warm climates in the early palaeogene, geological society of america, special paper, 369, 275–290. sprong, j., speijer, r.p. & steurbaut, e. (2009): biostratigraphy of the danian/selandian transition in the southern tethys: special reference to the lowest occurrence of planktic foraminifera igorina albeari.– geol. acta, 7/1–2, 63–77. stampfli, g., favre, p., pillevuit, a. & vannay, j. (1995): the neotethys-east mediterranean basin connection.– in: 2nd international symposium the geology of the eastern mediterranean region, abstract book, p. 17. steurbaut, e., dupuis, c., arenillas, i., molina, e. & matmati, m.f. (2000): the kalaat senan section in central tunisia: a potential reference section for the danian/selandian boundary.– in: scmitz, b., sundquist, b. & anreasson, f.p. (eds.): early palaeogene warm climates and biosphere dynamics, gff, 122/1, 158.160. doi:10.1080/11035890001221158 steurbaut, e. & sztrakos, k. (2008): danian/selandian boundary criteria and north sea basin. tethys correlations based on calcareous nannofossil and foraminiferal trends in sw france. marine micropaleont., 67, 1–29. strougo, a. (1986): the velascoensis event: a signifi cant episode of tectonic activity in the egyptian palaeogene.– n. jahrb. geol. paläont., abhand., 173, 253–269. tantawy, a.a. & keller, g. (2004): biotic effects of volcanism on calcareous nannofossils and planktic foraminifera: ninetyeast ridge, indian ocean.– egypt. j. paleont., 3, 1–23. tantawy, a.a., keller, g., adatte, t., stinnesbeck, w., ka ssab, a. & schulte, p. (2001): maastrichtian to palaeocene depositional environment of the dakhla formation, western desert, egypt: sedimentology, mineralogy, and integrated microand macrofossil biostratigraphies.– cretac. res., 22, 795–827. doi:10.1006/ cres.2001.0291 tantawy, a.a., zakhera, m. & kassab, a. (2003): biostratigraphy and paleoecology of the upper cretaceous-palaeocene sequence, northern scarpe of farafra oasis, western desert.– in: abstracts of the 3rd annual meeting of paleontological society of egyptian, p. 6–7. thierstein, h.r. (1981): late cretaceous nannoplankton and the change at the cretaceous–tertiary boundary.– in: warme, j.e, douglas, r.g. & winterer, e.l. (eds.): the deep sea drilling project: a decade of progress, sepm special publication, 32, 355–394. van itterbeeck, sprong, j., dupuis, c., speijer, r.p. & steurbaut, e. (2007): danian/selandian boundary stratigraphy and ostracod records from sidi nasseur, tunisia.– marine micropaleont., 62, 211–234. varol, o. (1989): palaeocene calcareous nannofossil biostratigraphy.– in: crux, j.a. & van heck, s.e. (eds.): nannofossils and their applications, british micropalaeontological society, 12, 267–310. worsley, t. & martini, e. (1970): late maastrichtian nannoplankton provinces.– nature, 225, 1242–1243. youssef, a.m. (2009): high resolution calcareous nannofossil biostratigraphy and paleoecology across the latest danian event (lde) in central eastern desert, egypt.– marine micropaleont., 72, 111– 128. doi:10.1016/j.marmicro.2009.03.007 manuscript received june 22, 2011 revised manuscript accepted march 04, 2012 available online june 29, 2012 geologia croatica 45 63-68 10 fig. 2 tab. zagreb 1992 udc 552.08:548:549.655(497.17) scientific paper crystallographic determination of titanite from smilevski dol in selečka mountain, macedonia vladimir zebec and biserka radanović-gužvica key words: titanite, morphology, crystal forms, smilevski dol on 30 crystal s of titani tc, goniometrically measured, the appearance of faces of 25 forms was determined. crystallographic elements were calculated and morphology and paragenesis of minerals were described. the shape of the crystals was represented by ten parallel perspec· tive figures. two types of crystal s were separated. l. introduction numerous pegmatitic and pegmatite-hydrothermal veins were found in the granites and gneisses of selečka mountain. some of them often contain well-formed crystals. one such vein was found about 2.5 km s south­ -west from the village dunje on the southern side of the hijiock g omi kamen ( elevation 636) near by the spring sohlehov kladence in smilevski dol. this vein con­ tains hydrothermally deposited well-formed crystals of albi te, epidote, titani te, amphiboles with somewhat less of quartz, muscovite, heulandite and stilbite, pyrite, apatite, microcline and chlorite. lj. barić (1958) gave the short description of some minerals from this locality. crystals of al bite (raff aelli, 1961 ), ep i dote (zebec, 1984) and stilbite and heulandite (tibuas et al., 1987) have been in detail e laborated up today. on one of specially yellow and clear crystal of titani te barić (1958) determined the following forms: {100}, { 110}, { 021}, (111}, (i12}, (ill}, (212} and (132}. 2. experimental procedure the investigated material was chosen after the re­ view of all collected crystals by stereomicroscope. the crystals chosen for the quality of their faces could be a solid basis for the precise determination of the crystallographic constants which were estimated by goniometric measurements. goniometric measurements were performed on the two-circular reflecting goniometcr (model a by goldschmidt). measurements were per­ formed at a polar setting of both sides of a crystal, if it was possible. the obtained data were middling and if conditions of the observations allowed, were used for determination of the crystallographic elements. the remaining data were used for identification of the measured faces. ključne riječi: titanit, morfologija, kristalne forme, smilevski dol na 30 goniometrijski mjerenih kristala titanita određeno je prisustvo ploha 25 formi. izračunati su kristalografski elementi te opisana morfologija i parageneza. izgled krista la prikazan je u 10 paralelno perspektivnih slika. izdvojena su dva tipa kristala. 3. material the material was predominantly collected by prof. lj. barić in 1952., whereas a certain part was collected and ceded by m. galeski and z. gruevski. the elaborated material is being kept in the collection of mineralogic-petrographic department of croatian museum of natural history in zagreb, inven tary numbers: 600:zag;5781 :mp l , 600:zag;5782:mp1, 600:zag;7711:mp1 600:zag;7712:mp1. 4. the results of goniometric measurements 30 crystals of titanite, size from 2 to 8 mm s, were chosen for goniometric measurements. the orientation by descloizeaux was taken. determination of the faces was performed by gnomon projection. the faces of 25 forms were determined on the measured crystals of the titanite. a review of form combinations on single crystal s is shown in table l. the faces of the forms l41 o), { 364} and ( 564} were not determined up to now, in the reference which was disposable to as (mineraly iii/l, 1972). the results with the optimal conditions of measurements are shown in table 2. 5. calculation of crystallographic elements the elements of gnomon projection were calculated from the best values obtained by measurements (table 2) as suggested by goldschmidt (1934): x; = 0,570260 p 0 1 = l ,303487 q; = 0,854633 then, the polar elements were calculated from elements minerulogic·pctrographic department of croatian museum of natural history, demetrova l, 41000 zagreb, c roatia mineraloško·petrografski odjel hrvatskog prirodoslovnog muzeja demetrova l , 41000 zagreb, hrvatska .,., v ~ ·:::: e u .. "oj, o ] o ~ simbol of form crystal num. (kristal br.) (simbol forme) l 2 3 4 5 6 7 8 9 10 ll 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 001 + + + + + + + + + + + + + 010 + + 100 + + + + + + + + + + + + + 410 · + 310 + + + + + + + + + t. + 520 + + + 110 + + + + + + + + + + + + + 130 + 021 + + + + + + + + + 101 + + + + "102 + + + + + + + + + + + + + ll l + + + + + + + + + + + + + .. llj + ±14 + .!12 + + + + + + + + + + + ±ll + + + + + + + + + + + + 2 2'1 212 + + + + + + + + + + + + 131 + 122 + 364 + ~6.4 + !3~ + + + + + + + 312 + 35·4 + fi~i .. (sl) 6 9 ? · 8 l ___ _.___ ____ ----table l tita~te, smilevski dol, review of combination of the forms on single crystals tablica l. titanit, smi.j.evski ol, pregled kombinacija formi na pojedinim kris~a + + + + + + + + + + + + + + + + + + +. + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + . + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + 2. s 3 4 lo zebec & radanović-gužvica : crystallographic detrrninati9n of titanite ... nm bol number of variation of form (kolebanja) (simbol observation forme) (broj opažanja) <p p 001 ll 89°48'90°20' l'j"37'30"03. ll o 1 56.41's6•s8 · 9o•oo· ll o s 77°19'77"57' 9o•oo· 102 14 89.56'9o•o5· so•21·5o•4&' 111 ll 65°25'. 65°36' 63°59'64"15' 111 1 jn•n·-319"37' 48"22'48"29' i12 9 348°56 '-349°35' 23'24'23'37' table 2. titanite, smilevski dol, review of the best value. of gnomon projection: x, = 0,4954 po= 1,1323 q. = 0,7424 ilo= 60° 18,5' linear elements of the titanite from smilevski dol, calculated from polar elements, were: a:b:c = 0,7548 : i: 0,8546 p= 119' 41,5' the obtained result corresponds well with the data found in literature: a:b:c = 0,7547: l : 0,8540 p= 119' 43' (goldschmidt, 1897). 6. morphology of crystals titanite and epidote form the best shaped crystals of the vein association, and this was the reason why quantitative crystallometric determination was done. crystals are of different size, from l to 40 mms, and are predominantly elon gated in direction of zone made by the faces of form ( 111} , that is, in direction [i o l] . an exception was a crystal which was shortened in this direction (fig. 10). roughly, speaking, two types of crystals can be separated : one with well-formed faces of prism of general position { 114}, and strongly well­ -formed faces of form (001} and the other without the faces of form { 114}, with slightly outstanded faces of fonn (001}. among measured crystals prcdominant are those from the second group (4/5 of measured crystals). faces of the forms ( 102} i (212} give specific habitus to crystals. the faces of the forms {oo l } , { l oo} and { 111 } were noticed on all crystal s. the faces of the forms ( 31 o} , {110}, (021}, {102}, {112}, {111}, (212} and {132} were very frequent.the faces of the forms {010}, {520}, { 10 l } , { 114} and ( 221 } were rare l y observed. the faces offorms (410}, (130}, {113}, (131}, (122}, (364}, { 564}, (312} and {~54} were observed on only one crystal. the quality of the faces, even of the faces of the same form on the same crystal was usually differ­ ent. this was, particularly evident on different crys­ tals. some crystals were partially subjected to dissolution. together with shiny faces the faces corroded by dis­ solution were also found, especially in their central parts. the best example was the face of the form ( 100} which could range in quality from shiny and ideal smooth to mean value calculated value (srednja vrijednost) (izračunata vrijednost) <p p <p p 89"59'36'. 29"46'17" 90"00' 29"41'40'. s6•so•37'' 90"00' 56°44.57 •• 9o•oo• 77°36'26'' go•oo• 77"40'19'. 90"00' 90"00' 12'' 50°41'27'' 90"00' 50•42 • 21' • 65°3'4'0~·. 64°05' 33 •• 65"28'59'. 64°06'02" 319"23'00'' 48°31'05'' 319°22'12'' 48"23'36'' 349"16'42'. 23"31' 24 .. 349"12'06'. 23•30'33'. tablica 2. titanit, smilevski dol, pregled najboljih vrijednosti. striated and even hieroglyphically coroded ones. the curving of described elongation zone in the plane of symmetry was noticed on bigger crystals. a free part of one crystal was curved for about 20° toward [100) (600:zag;5781:mp1). so, in the attempt to better show the morphology of titani te crystals from smilevski dol, besides appart from the table l, which shows the presence of the combination of faces of particular forms, paral­ lel perspective figures of first (figs. 1-4) and second type of characteristic crystals (figs. 5-10) were con­ structed. it is interesting that in whole material, in neither of the cases the twins of titanite were registered. 7. paragenesis the beginning of crystallization of titanite, in our case, began after the crystallization of muscovite, pyrite, older and main parts of plagioclases, amphiboles and older epidote. the youngest minerals (albite, apatite, part of amphiboles, epidote and chlorites) were crys­ tallized together with titanite. microcline and zeolites were younger of titanite. titanite appears abundantly, predominantly with amphibole, which, by its optical characteristics, can be determined as hornblende. the interacting relation between the two noticed types of crystals of titanite could not have been determined. for the other titanic minerals, very rarely, tiny crystals of rutile could have been found. on some ciystals of titanite, chlorite inclusion were found abundantly. 8. conclusion well-formed crystals of titanite from smilevski dol near dunje in selečka mountain originated from hydro­ thermal veins of alpic type with the following paragen­ esis: muscovite, albite, pyrite, hornblende, epidote, apa­ tite, chlorite, microcline, heulandite and stilbite. on the examined crystals a prcsence of the faces of 25 forms were determined {table l). these crystalographic elements were determined: a:b:c = 0,7548 : l : 0,8546 p=119' 41,5'. two types of titanite crystals were separated. the (irs t type is shown in figures 1-4, and the second one in figures 5-10. their interacting relation was not determined. 66 fig. l -4. titani te, srni l evski dol, crystal s of the firs t type. slika 1-4. titanit, smilevski dol, kristali prvog tipa. 9. references baric, lj. (1958): mineralienfundort in smilevski dol bei dunje in mazedonien.bull. sci. cons. acad. yougosl.4/l, l, zagreb. goldschmidt, v. (1897): krystalographi sche winkeltabellen.verlag von julius springer, 344 p ., berlin. goldschmidt, v. (1934): kursusderkristallomelrie. -verlag von gebruder borntraeger, berlin. mineraly ,tom iii, vyp., i. akademija nauk sssr, geologia croatica 45 "nauka",1972, moskva. raffaelli, p. (1961): albite from smilevski dol in selečka mountain, macedonia.geološki vjesnik, 14, 133-142, zagreb. tibuas, d., zebec, v. & bermanec, v. (1987): zeolite occurrence in the vein mineral paragenesis near dunje, macedonia.geološki vjesnik, 40, 81-87, zagre b. zebec, v. (1 984): epidot von smilevski dol bei dunje im selečka-gebirge (mazedonien).geologica macedonica, 1/1, 63-122, š tip. zebec & radanović-gužvica : crystallographic dctrrnination of titanite ... fig. 5-8. titani te, smilevski dol, crystal s of the second type. slika 5-8. titanit, smilevski dol, kristali drugog tipa. 67 68 geologia croatica 45 . fig. 9~10. titanite, smilevski dol, crystals· of th~ second type . ." slika 9-10. titanit, smilevski dol, kristali drugog tipa. kristalografska određivanja na titanitu"iz smilevskog dola na selečkoj planini, makedonija v. zebec i b. ~adanović-gužvica u granitima i gnajseviina selečke planine nalaze se brojne · pegmatitne i pegmatitno-hidrotennalne žice. jedna takva žica · otkrivena je oko 2,5.km jugozapadno od sela dunje, na južnoj slrnni l,iz~ gomi kamen (kota 636).u blizini izvom ~ov 1\laden~ u smilevskom dolu. ta žica sadrži, hi9rote~o . odložene.oo~razvitre~albita.~tilanitiamfioola · sa nclto manje kremena, m usko vila, heulandita.i stilbit<i, pirila, .. apatiti, mikroldina i klorita. · za goo.iometri jska istraživanja izabrano je 30 kristala ti !anita veličineod.2do8 mm. uzetajeorijenlacija po descloizeaux:­ u, indiciran je ploha izvršeno je iz gnomonske projekcije. na · mjer~ini kristalima ovog tilanita pritom su utvrđene ·plohe . 25 formi. pregled kombinacija fonni na pojedinim kristalima : · danje u tablici l. plohefonni {410), {364) i {564), u nama·. . dostupnoj literaturi; nisu do sada određene {mineraly lli/l, . 1972). {) tablici 2 predočeni su rezullati sa najpovoljnijim uvjetima mjerenja . na temelju najboljih, mjerenjem polučenih vrijednosti, izračunati su kristalografski elementi: . . a:b:c = 0,7548: l: 0,8546 ~119' 41,.5' kristali titani ta iz smilevskog dola uglavnom su izduženi · smjeromzoneštojučineplohefonne {ll l) ~. smjeront [iol]. grubo se mogu izdvojiti dva tipa kristala: 1.) oni sa razvijenim plohamafonne {114) ijačerazvitimplohamafonne {001) (sl. l -4) i 2.-)oni bez ploha fonne 114 ; pri čemu su i plohe fonne (001)' sfabije izražene (sls~ 10). među izmjerenim kristalima prevl~tlavaju oni iz druge skupine (4/5 izmjerenih . kristala). njfhova m~usobna veza nije određena. neke kijstale je dijylom z3hva~lo i otapanje, pa pored sjajnih ploha nal~imo i otapanjem izjedene plohe, naročito u njiho~om centralnom dijelu.' . na .većim kristalima zam jeće no je savij an je osi opisane . zone izduženja u ravnini simetrije. slobodni kraj kristala pri tom. je savinut za oko 20 prema [100]: ·počelaklcristal.izxije tilanita; u ovom slučaju, treba smjestiti iza kristalizacije muskovita, pirita te starijeg i glavnog' dijela plagioklasa, am fi bola i starijeg epidota. zajedno sa titanitom kristalizirati su najmlađi al bit, apatit, dio amfibola, epidot i klorit mlađi od tilanita s~ mikroklin i zeoliti. od drugih titanskih minerala vrlo rijetko može se naići na sirne kristaliće rutila . .. na nekim ·kristalima titani ta iz smilevskog dola obilnije je konstatitan klorit kao uklopak u titanitu. manuscript received march, 31. 1992. revised manuscript accepted june, 23. 1992. mauch.indd 207 jadranka mauch lenardić: first record of the root vole microtus oeconomus (pallas, 1776) (arvicolidae, rodentia, mammalia) in croatia... � ab stra ct late pleistocene remains of microtus oeconomus (pallas, 1776), a species that is not any more a member of the extant fauna of croatia, have been recently found in vindija cave sediments. the sample of 21 teeth shows a slight increase of m1 length and decrease of a/l ratio within the cave sequence from older (g complex; 32 to 42 ka) towards younger strata (e+f complex; layer e is dated at ca. 18.5 ka). the most frequent morphotype is type b sensu nadachowski (1982). the new record does not allow further detailed ecological implications than what is already known about the late pleistocene habitats in this region. keywords: root vole, microtus oeconomus, teeth, morphometric analyses, late pleistocene, vindija cave, croatia first record of the root vole microtus oeconomus (pallas, 1776) (arvicolidae, rodentia, mammalia) in croatia – fossil remains from the late pleistocene of vindija cave � jadranka mauch lenardić institute for quaternary palaeontology and geology, croatian academy of sciences and arts, ante kovačića 5/ii, hr–10000 zagreb, croatia; (jml@hazu.hr) doi:104154/gc.2011.17 geologia croatica 64/3 207–212 5 figs. 4 tabs. zagreb 2011 geologia croaticageologia croatica 1. introduction vindija cave is a well known pleistocene locality in croatia. its pleistocene sediments (mis 6 – mis 2) (figs. 1 & 2), contain numerous small mammal remains and other faunal representatives. during more than a decade of continuous excavations at the site (1974–1986 conducted by mirko malez), these discoveries were collected with variable care and/or appropriate methods (miracle et al., 2010, and references therein). more accurate collecting has been performed during excavation of complex g (32–>42 ka /higham et al., 2006; wild et al., 2001/), containing neanderthal remains and of complex e+f (18.5–30 ka /wild et al., 2001/), with remains of modern humans (fig. 2). the majority of the dental and other skeletal microvertebrate remains including microtus oeconomus (mauch lenardić, 2004, 2005), originates from the sediments of these strata, while one m1 originates from older sediments of the layer i (ca. 88 ka; wild et al., 2001). microtus oeconomus is the only extant microtus species with a holarctic distribution and ranges from northwest europe, eastward through north and central asia to alaska and northwest canada (brunhoff et al., 2003). four phylogeographical groups have been identifi ed and traced back to several glacial periods. they refl ect late glacial and postglacial range expansions and shifts as well as fragmentation of populations (idem). 2. geological settings the geographic position of the cave is 46° 18’ 12’’ n, 16° 14’ 38’’ e, and the entrance is 275 m a.s.l. (paunović et al., 2001; wild et al., 2001, and references therein). the cave consists of a single, funnel-shaped chamber over 50 m long, 28 m wide and 20 m high, although prior to exca vation, the cave roof was less than 3 m above the surface (miracle et al., 2010). geologia croatica 64/3geologia croatica 208 thirteen layers (from the youngest a /holocene/ to the oldest m /mis 6 or older/) show different sedimentation cycles, and comprise faunas of different composition. microtus oeconomus teeth have been uncovered from stratigraphic units i, g lower, g upper (inclusive signature g2), complex e+f and layer e (after original signature; see fig. 2). 3. material and methods the determinations, terminology and metrical methods were used after van der meulen (1973), rabeder (1981) and nadachowski (1982). measurements: the overall tooth length (l), the length of anteroconid complex (a) and width (w) have been measured and a/l index was calculated (according to van der meulen, 1973). all measurements are in millimetres (mm). the parameters have been statistically calculated with statistica 6.0 figure 1: location map of vindija cave. figure 2: stratigraphic column of vindija cave sediments with 14c and u/th data (after wild et al., 2001). * – data after higham et al. (2006); arrows mark the layers with microtus oeconomus. geologia croatica 209 jadranka mauch lenardić: first record of the root vole microtus oeconomus (pallas, 1776) (arvicolidae, rodentia, mammalia) in croatia... (statsoft.inc., 1994–2001 for windows). on graphs standard deviation (sd), standard error of the mean (se) and mean values are indicated. morphotypes: morphotypes of m1 have been determined and named after nadachowski (1982) (fig. 3). morphotype b: with pronounced lsa5. morphotype c: with smooth bsa4 and bra4 of varying size (example a – lesser distinct, example b – more distinct). width between t5 and t6 (confl uence) varies. morphotype d: with bsa4 very well developed, connection between t5 and t6 is very narrow (not confl uent). the fossil material is stored at the institute for quaternary palaeontology and geology of the croatian academy of sciences and arts in zagreb. abbreviations: used abbreviations are: sin. (sinister = left), dext. (dexter = right), m1 (fi rst lower molar), m2 (second lower molar), lsa5 (fi fth lingual salient angle), bsa4 (fourth buccal salient angle), bra4 (fourth buccal re-entrant angle), t5, t6 (fi fth, sixth triangle), ka (thousands of years), n (number of specimens), min. (minimal value), max. (maximal value), mis (marine isotope stage), lg (last glacial). 4. results order rodentia bowdich, 1821 suborder myomorpha brandt, 1855 superfamily muroidea, illiger, 1811 family cricetidae fischer von waldheim, 1817 subfamily arvicolinae gray, 1821 tribe arvicolini gray, 1821 genus microtus schrank, 1798 microtus oeconomus (pallas, 1776) 1982 microtus oeconomus – nadachowski, p. 74–81, fi gs. 20, 21, 22; material: 7 m1 sin. (inv. numbers: 23-1, 32-1, 70-1, 164-1, 202-1, 213-1 and 419-2), 12 m1 dext. (inv. numbers: 20-1, 39-1, 40-1, 45-1, 50-1, 73-1, 77-1, 160-1, 206-1, 207-1, 45-proba iii and 46-proba iii), and 2 m2 sin. (inv. numbers: 23-1 and 70-1). description: m1 with four, rarely with fi ve closed triangles; with weakly developed t6; bsa4 sometimes present; specifi cally shaped anterior cap (lobus) with fl attened buccal side. t5 is mostly broadly confl uent with t6 and anterior lobus on the occlusal surface (fig. 3). measurements: first lower molars (m1): l, a, w and a/l values are given in figs. 4 and 5, and tab. 1. measured parameters were grouped and compared for two complexes – e+f and g. mean values for l, a and w are greater for the samples from the e+f complex than for the g complex (figs. 4 and 5), while for the a/l index is opposite. figure 3: morphotypes of microtus oeconomus fi rst lower molars (m1) from vindija cave: b (layer e, inv. no. 207; inverted image), c (a – layer g2, inv. no. 70; b – layer i, inv. no. 419), and d (layer g2, inv. no. 40; inverted image). bar scale is 1 mm. figure 4: graph of mean values, standard error of the mean values (se) and standard deviation (sd) for length l (a) and length of anteroconid complex a (b) of microtus oeconomus m1 for the vindija cave e+f and g complexes. geologia croatica 64/3geologia croatica 210 second lower molars (m2): only two m2 (tab. 2) with values of l and w enable no morphometrical analysis. morphotypes: on 19 m1 of microtus oeconomus, (12 of them are from the g complex), morphotypes b, c and d sensu nadachowski (1982) have been identifi ed (fig. 3; tab. 3), while morphotype a is completely absent. in the small sample, the most abundant morphotype is b (10 teeth or 52.6 %). 5. discussion based on m1 morphology alone, a specifi c determination between microtus oeconomus and chionomys nivalis might be in some cases problematic, since (as shown by angermann, 1971) that both species share common m1 morphotypes. in his paper about late quaternary rodents of poland, nadachowski (1982) elaborated this problem in fossil material. the „oeconomus« morphotype is the most frequent in the polish late pleistocene samples, but decreases during the late glacial. nadachowski (1982) assumes that at the margin of the species range, non-typical morphological features occur more frequently, which parallels the situation during the last glaciation when under the infl uence of ameliorating climate the root vole retreat to the north, and the frequency of the „alien« morphotypes increased to 36 %. also the extreme frequency of the nivalid morphotype (35 %) is observed in recent populations inhabiting the tundra zone (nadachowski, 1982). the comparison between the frequency of microtus oeconomus of various polish sites shows even greater differences (from 2–5 % to 46 %), but up from the upper pleniglacial a gradual decrease is observed: from 10–30 % in the upper pleniglacial, to 4–17 % in the late glacial and eventually to 1–8 % during the holocene (nadachowski, 1982). however, analysing the vole dentition from bacho kiro cave (bulgaria) nadachowski (1984) corrected the previous determination of m1 of microtus cf. oeconomus to extreme variants (morphotype a) of the snow vole chionomys nivalis (martins, figure 5: graph of mean values, standard error of the mean values (se) and standard deviation (sd) for width w (a) and a/l index (b) of microtus oeconomus m1 for the vindija cave e+f and g complexes. table 1: minimum (min.), mean and maximum (max.) values of l and a/l for microtus oeconomus m1 from vindija cave. layer/ complex l a/l n min. mean max. n min. mean max. e 4 2.57 2.69 2.83 4 40.13 48.01 50.18 e+f 2 2.61 2.70 2.78 2 49.64 49.92 50.19 gupper 10 2.29 2.56 2.76 10 47.16 48.87 52.90 glower 2 2.57 2.66 2.75 2 49.42 49.99 50.55 i 1 2.94 1 47.96 table 2: measurements (l and w) for microtus oeconomus m2 from vindija cave. inv. no. layer/complex l w 23-3 (sin.) e+f 1.48 0.87 70-1 (sin.) g2 1.54 0.96 table 3: morphotype frequencies for microtus oeconomus m1 from diff erent layers/complexes of vindija cave. layer/ complex morphotypes b c d total n % n % n % n % e+f 4 66.7 2 33.3 6 31.6 gupper 6 60.0 3 30.0 1 10.0 10 52.6 glower 2 100 2 10.5 i 1 100 1 5.3 total 10 52.6 8 42.1 1 5.3 19 100 geologia croatica 211 jadranka mauch lenardić: first record of the root vole microtus oeconomus (pallas, 1776) (arvicolidae, rodentia, mammalia) in croatia... 1842) based on data of fossil and recent samples from switzerland, the tyrol, murańska cave and other localities in the tatras, greece, romania, bulgaria etc. in the m1 of vindija cave, the most frequent morphotype is b (52.6 %; four closed triangles), morphotype c is less abundant, morphotype d is represented by one tooth only, and morphotype a is completely lacking. these data would fi t roughly between the values of the late glacial and recent condition in polish samples, documented by nadachowski (1982): lower pleniglacial (lp) – 61.7 %, upper pleniglacial (up) – 60.9 %, late glacial (lg) – 46.8 %, recent (r) – 59.2 %. the metrical analysis of m1 of microtus oeconomus shows an increase of the length and a decrease of the a/l index from the older g to the younger e+f complex. also nadachowski (1982) observed a distinctive increase of m1 length during the late quaternary of poland (with the smallest specimens in the lower pleniglacial, and the biggest in the extant fauna – idem). the mean a/l values from poland fl uctuate between 48 and 49 but the differences between the groups are not statistically signifi cant. in the vindi ja sample, the maximal values are somewhat smaller, and minimal values are slightly bigger compared to the polish samples, whereas the mean values remain more or less similar. however, l and a/l are smaller in the croatian samples compared to the polish ones (tab. 4) (nadachowski, 1982; mauch lenardić, 2005). comparison of m1 length gives similar mean values for the vindija e+f complex sample and recent german specimens (tab. 4; tast, 1982). according to spitzenberger & bauer (2001), a morphological rather similar ancestor of microtus oeconomus fi rst appeared in the lower pleistocene, and specimens of the present shape during the middle pleistocene respectively. they quote the oldest ‘true’ m. oeconomus as being from the volcanic ash in the open-site miesenheim near koblenz (rheinland-pfalz, germany), dated at 612 ka. microtus oeconomus belongs to the holarctic pleistocene tundrasteppe fauna, which existed during the lg (more than 55 ka), and therefore also occurred on the north american continent. the species also occurs in some late pleistocene austrian localities (gamssultzenhöhle, grossen ofenbergerhöhle: upper würmian, nixloch: dryas – 10.55 ka until holocene) (spitzenberger & bauer, 2001). within the late pleistocene and holocene, several populations west and south of the recent main distribution of m. oeconomus became isolated. in southern germany, the czech republic and hungary, the species was still recorded in the holocene, in moldova until the neolithic, and in southern france, as the last boreal element of ice age fauna, the species disappeared ca. 7000 years ago (spitzenberger & bauer, 2001). recent investigations in hungary have confi rmed the presence of some isolated (sub)populations, one near balaton lake (ne), and a second (barcs), about 100 km east of the vindija site (bihari et al., 2007). the distribution is confi rmed by nadachowski (1982) who mentions a late pleistocene expansion of the range of microtus oeconomus further west than today: in central europe, england, france and switzerland as well as further south in hungary and romania. the species survived here longer than many other tundra adapted species; e.g., in hungary it still occurred during the subboreal (bükk phase) in the bükk mountains, and in the caves of the aggtelek karst (nadachowski, 1982). at the beginning of the holocene, the distribution of this species was divided into two parts: a tundra range and a forest-tundra range of europe, parts of asia and north america, with isolated populations in the netherlands, austria and the small hungarian lowland (nadachowski, 1982). microtus oeconomus is an indicator of a cold climate and tundra-forest environments with abundant water, respectively (nadachowski, 1982). tundra (root) voles appear to have an extremely wide tolerance to different habitats, but may be locally restricted by competition with other microtines (guthrie, 1968). in some regions, microtus oeconomus could be restricted to low wetland communities, unforested areas, wet meadows, around lakes, streams or mar sh es (gubányi et al., 2007). microtus oeconomus has been determined for the fi rst time in croatia in the late pleistocene sediments of the vindija cave (mauch lenardić, 2004, 2005), and it is not part of the extant fauna in the vicinity of the cave (petrov, 1992). thus the fi ndings from vindija cave imply a somewhat colder and more wet climate in this region during some phases of the late pleistocene than today. the youngest strata from which this species is determined in vindija is the e+f complex (layer e is dated as ca. 18.5 ka). there are no records of this species in younger layers, neither are there in the faunal remains from other croatian localities with contemporaneous strata, such as marlera i (southern istria), the mu jina pećina cave (middle dalmatia; mauch len ardić, 2005, 2008) or vela spila on korčula island, respectively (mauch lenardić, in press). acknowledgement the author is grateful to drs. lutz c. maul and nikola tvrtković for their valuable comments and improving the earlier draft of the manuscript. this study was part of the authors phd thesis research and part of the former institute’s projects by ministry of science, education and sports of the republic of croatia, project: “biostratigraphical correlation of palaeolithic and mesolithic of croatia” no. 101711 (from 1997 till 2001), and project “palaeolithic and mesolithic of croatia: settlement of the eastern adriatic in pleistocene” no. 0101018 (from 2002 till 2006). table 4: tooth length (l) and a/l index for microtus oeconomus samples: * – germany (fürstenwalde near berlin; tast, 1982); ** – poland (diff erent localities; nadachowski, 1982). age (in ka bp) l a/l n min.–max. mean n min.–max. mean r (germany)* 15 2.05–2.90 2.71 – – – r (10 – 0)** 30 2.74–3.37 2.98 30 43–52 48 lg (16 – 10)** 16 2.64–2.96 2.84 16 46–51 49 up (30 – 16)** 30 2.50–3.19 2.77 30 46–54 48 lp (62 – 52)** 30 2.47–2.89 2.65 30 45–52 49 geologia croatica 64/3geologia croatica 212 references angermann, r. (1971): die zahnvariabilität bei microtinen im lichet von vavilov’s “gesetz der homologen reihen”.– in: kratochvil, j. (ed.): proceedings of the international symposium on species and zoogeography of european mammals, prague, 63–71. bihari, z., csorba, g. & heltai, m. (eds.): magyarország emlőseinek atlasza.– kossuth kiadó, 2007, budapest, 360 p. brunhoff, c., galbreath, k.e., fedorov, v.b., cook, j.a. & jaarola, m. (2003): holarctic phylogeography of the root vole (microtus oeconomus): implications for late quaternary biogeography of high latitudes.– molecular ecology, 12, 957–968. gubányi, a. (2007): északi pocok, microtus oeconomus (pallas, 1776).– in: bihari, z., csorba, g. & heltai, m. (eds.): magya rország emlöseinek atlasza, kossuth kiadó, budapest, 164–165. guthrie, r.d. (1968): paleoecology of a late pleistocene small mammal community from interior alaska.– arctic, 21/4, 223–244. higham, t., bronk ramsey, c., karavanić, i., smith, f.h. & trinkaus, e. (2006): revised direct radiocarbon dating of the vindija g1 upper paleolithic neandertals.– proceedings of the national academy of sciences of the united states of america (pnas), 103/3, 553–557. mauch lenardić, j. (2004): morphometric analyses of arvicolids from some croatian localities.– terra nostra schriften der alfredwegener-stiftung, berlin, 2004/2, 167. mauch lenardić, j. (2005): metrijska i morfotipska analiza zuba gornjopleistocenskih voluharica hrvatske [morphometric analyses of upper pleistocene arvicolid teeth from croatia – in croatian, with english abstract and summary].– unpubl. phd thesis, faculty of sciences, university of zagreb, 166 p. + lxxxv p. appendix. mauch lenardić, j. (2008): the middle paleolithic from mujina pećina, dalmatia, croatia.– j. field arch., 33/3, 259–277. mauch lenardić, j. (in press): small mammals of vela spila (island of korčula, croatia). bar international series, archaeopress, publishers of british archaeological reports. miracle, p.t., mauch lenardić, j. & brajković, d. (2010): last glacial climates, “refugia”, and faunal change in southeastern europe: mammalian assemblages from veternica, velika pećina, and vindija caves (croatia).– quaternary international, 212/2, 137–148. nadachowski, a. (1982): late quaternary rodents of poland with special reference to morphotype dentition analysis of voles.– polska akademia nauk, zakład zoologii systematycznej i doś wiadczalnej, państwowe wydawnictwo naukowe – oddział w krakowie, 109 p. nadachowski, a. (1984): morphometric variability of dentition of the late pleistocene voles (arvicolidae, rodentia) from bacho kiro cave (bulgaria).– acta zoologica cracoviensia, 27/9, 149–176. paunović, m., jambrešić, g., brajković, d., malez, v. & mauch lenardić, j. (2001): last glacial settlement of croatia: catalogue of fossil sites dating to the ois 2&3.– acta geologica, 26/2, 27–70. petrov, b.m. (1992): mammals of yugoslavia. insectivores and rodents.– suppl. nat. hist. museum belgrade, 37, 186 p. rabeder, g. (1981): die arvicoliden (rodentia, mammalia) aus dem pliozän und dem älteren pleistozän von niederösterreich.– beiträge zur paläontologie von österreich, 8, 1–373. spitzenberger, f. & bauer, k. (2001): sumpfwühlmaus, nordische wühlmaus microtus oeconomus (pallas, 1776).– in: die säugetierfauna österreichs. grüne reihe des bundesministeriums f. landund forstwirtschaft, umwelt und wasserwirtschaft, bd. 13, verlag austria medien service gmbh, graz, 456–461. statsoft, inc. statistica (data analysis soft-ware system), version 6. 1994–2001. tast, j. (1982): microtus oeconomus (pallas, 1776) – sumpfmaus.– in: niethammer, j. & krapp, f. (eds.): handbuch der säugetiere europas, band 2/i: nagetiere ii, akademische verlagsgesellschaft, wiesbaden, 374–396. van der meulen, a.j. (1973): middle pleistocene smaller mammals from the monte peglia, (orvieto, italy) with special reference to the phylogeny of microtus (arvicolidae, rodentia).– quaternaria, 17, 1–144. wild, e.m., paunović, m., rabeder, g., steffan, i. & steier, p. (2001): age determination of fossil bones from the vindija neanderthal site in croatia.– radiocarbon, 43/2b, 1021–1028. manuscript received february 14, 2011 revised manuscript accepted july 25, 2011 available online october 26, 2011 ab stra ct the ne hungarian darnó hill is geologically complex; it is composed of an accretionary mélange complex, which contains permian, triassic and jurassic sedimentary and magmatic blocks. the succession can easily be correlated with the nw dinarides, using evidences of the different evolutionary stages of the neotethyan ocean (rifting, marginal basin opening, closure). several ore indications are known from this area, but their genesis is poorly understood, mostly because of the complexity of the geological structures. the present study deals with one of these indications from deep drilling. a framboidal pyrite bearing permian-triassic marly limestone series was investigated, which was previously described as a possible analogy of the polish-german copper shales (kupferschiefer). framboidal pyrite, euhedral pyrite overgrowths (both with high au content), disseminated euhedral and anhedral pyrite (without overgrowth), anhedral chalcopyrite, galena and sphalerite were recorded by detailed microscopy, epma and whole rock geochemical analyses. there is a slightly enriched total metal content of 100-200 ppm in the mineralized sediments compared to the unmineralized ones. the minerals formed under reducing, anoxic, marine sedimentary conditions, in several steps; during synsedimentary, early diagenetic and epigenetic processes. the characteristics confirmed by the research are typical of the weakly mineralized kupferschiefer type. keywords: weakly mineralized kupferschiefer type, permian-triassic sediments, framboidal pyrite, euhedral pyrite overgrowth, micrograins of chalcopyrite, sphalerite and galena geologia croaticageologia croatica development of framboidal pyrite in the upper permian marly limestone of the ne-hungarian darnó hill  gabriella b. kiss1 and federica zaccarini2 1 department of mineralogy, eötvös loránd university, h-1117 budapest, pázmány p. stny. 1/c, hungary; (gabriella-kiss@chello.hu) 2 department of applied geosciences and geophysics, university of leoben, a-8700 leoben, peter tunner str. 5, austria doi: 10.4154/gc2013.19 geologia croatica 66/3 233–244 9 figs. 2 tabs. zagreb 2013 1. introduction several different mineralizations, such as native copper bearing calcite-zeolite veins and chalcopyrite bearing quartzprehnite veins in basalt, exhalative iron ore and a copper shale indication have been documented in the restricted 10 km2 area of darnó hill (fig. 1.) (haidinger, 1850, mezősi & grasselly, 1949, kiss, 1958, baksa et al., 1981, molnár & kiss, 2013). the genesis of the ore indications is mostly unclear due to the rather complex geology. a geological correlation has recently been established between darnó hill and the nw dinarides, based on stratigraphic, mineralogical and petrological data, as well as research on the tectonic evolution of the region. according to dimitrijević et al. (2003), haas & kovács (2001), kovács et al. (2008, 2010), haas et al. (2011) and kiss et al. (2008, 2010, 2012), the permian, triassic and jurassic sedimentary rocks, together with the triassic and jurassic submarine basalts of darnó hill, form a neotethyan accrétionary mélange complex, which was displaced from the dinarides to ne hungary along the mid-hungarian lineament. the recently accepted geological model has provided a reliable structural framework, within which the host rock sequence can be interpreted, focusing on the ore mineralization. the present study deals with the framboidal pyrite bearing copper shale indication, in order to provide geochemical and mineralogical data in this poorly studied mineralization, with the ultimate aim of providing more information regarding ore genesis. geologia croatica 66/3geologia croatica 234 figure 1: geological map of darnó hill. the location of the studied drilling (rm-131) and additional drilling, in which similar mineralization was localized (rm-135) are also shown. 2. geological background darnó hill (fig. 1) is part of the darnó unit, a part of the bükk unit, within the pelso unit of the alcapa block (al pine, carpathian, pannonian, csontos, 1995, schmid et al., 2008). according to the latest tectonic models, the darnó unit is the uppermost of four knappes, which compose the bükk unit. the lowest unit is the „bükk parautochton“, which contains palaeozoic to jurassic formations. the mónosbél unit, above it, is mainly composed of jurassic redeposited slope sediments. the szarvaskő unit contains an incomplete jurassic, back-arc-basin or marginal basin opening related ophiolite-like sequence associated with deep-sea sediments. the darnó unit is made up of triassic, neotethyan rifting related and jurassic, back-arc-basin opening related submarine volcanites and associated sedimentary rocks. these rocks form blocks in an accrétionary mélange complex of neotethyan origin. according to the latest tectonic models, the bükk unit can be correlated with the nw dinarides (aigner-torres & koller, 1999, csontos, 1995, csontos, 1999, dimitrijević et al., 2003, haas & kovács, 2001, harangi et al., 1996, kovács et al., 2008, kiss et al., 2010, 2012). deep drilling performed in 1977–78 revealed that two of the aforementioned units are present in the area of the darnó hill; the deeper positioned mónosbél unit and above it, the darnó unit (haas & kovács, 2001, kovács et al., 2008). among the slope sediments of the mónosbél unit, upper permian – lower triassic shale-limestone blocks as well as triassic neotethyan rifting related peperitic basalt blocks (similar to the ones found in the darnó unit) are observed (oravecz, 1978, kovács et al., 2008, kiss et al., 2010). the two units are partly covered by oligocene sedimentary rocks, miocene volcanites and sedimentary rocks, and with quaternary cover (földessy, 1975). the studied mineralization was discovered in two 1200 m deep cores (rm-131 and rm-135, fig. 1.), at the depth of 920-1050 m, in the mónosbél unit, when the drillcores were assayed in 10 m composite samples (baksa et al. 1981). in both cases, copper enrichment was found in upper permian – lower triassic limestone with shale intercalations, characterized by their high content of organic material. in the rm-131 core, the highest copper concentrations were between 930 and 940 m, but elevated values were observed from 890-990 m. the 0.1-0.28% cu content was attributed to chalcopyrite found on the rims of pyrite of bacterial origin. thus, the indication was interpreted as an analogue of the kupferschiefer deposits (i.e. black-shale hosted synsedimentary copper deposit), though several questions concerning the mineral paragenesis and the geochemistry remained unanswered (baksa et al., 1981). methods the studied 120 m deep rm-131 borehole was drilled in 1977–78 on the southern part of the darnó hill, in the framework of the structural geological research of the nearby recsk area. in the progress of this research, a 100m long part of the drillcore (900-1000 m) was studied in detail. below the strongly sheared zone, (from 900 m to 928 m), marly limestone with shale intercalations was detected. below this unit, from 990 m, there is a strongly tectonized zone. samples representing the typical features of all three units were studied in detail by microscopy (from 910.5 m, 912.8 m, 933.0 m, 950.0 m, 962.0 m, 965.4 m and 996.7 m). petrography of the samples with emphasis on the ore minerals was undertaken on polished thin sections. electron microprobe analyses were used to characterize the composition of the different types of pyrite crystals and overgrowths, chalcopyrite and sphalerite grains, and to obtain elemental maps of the framboidal pyrite and the euhedral pyrite aggregates. this study was undertaken at the eugen stumpfl laboratory of the university centre of applied geosciences (university of leoben, austria), where a superprobe jeol jxa 8200 instrument was used in wds mode, with 20 kv accelerating voltage and 10 na beam current. the beam diameter was about 1 μm. the x-ray lines used were: kα for s, fe, co, zn, cu and ni; lα for te, ag, sb, se and as; mα for au and pb. the following diffracting crystals were selected: petj for s, sb, pb, ag, au and te, lifh for cu, fe, zn, ni and co and tap for as and te. the counting time for peak and both backgrounds (left and right) were 20 and 10 seconds respectively. synthetic nis, au-ag alloy, agbise2, pdsb and bi2te3, and natural pyrite, chalcopyrite, kiss and zaccarini: development of framboidal pyrite in the upper permian marly limestone of the ne-hungarian darnó hill geologia croatica 235 figure 2: opaque minerals in the marly limestone. 1: framboidal pyrite (950 m, reflected light, 1n). 2: anhedral pyrite occurring along a stylolite in the marly limestone (950 m, 1n). 3: framboidal pyrite occurring together with euhedral pyrite overgrowths in the quartz and ca-mg carbonate formed host rock (965.4 m, composite image, epma). 4: framboidal pyrite occurring in the silicified marly limestone (962 m, composite image, epma). 5: disseminated chalcopyrite and galena occurring together with a euhedral pyrite aggregate (962 m, composite image, epma). 6: framboidal pyrite occurring together with fine-grained chalcopyrite and pyrite (962 m, composite image, epma). sphalerite, galena, skutterudite and niccolite were used as standard. the detection limits were as follows: 180 ppm for fe and co (co only for euhedral overgrowths sample 1-5, framboids sample 1-9 and chalcopyrite sample 1), 200 ppm for ni, 250 ppm for cu, 280 ppm for te, 300 ppm for s and zn, 350 ppm for ag, 390 ppm for sb, 400 ppm for se, 620 ppm for au, 700 ppm for as and 1100 ppm for pb, 1400 ppm for co (euhedral overgrowths sample 6-10, framboids sample 10-14, chalcopyrite sample 2-4, euhedral pyrite and sphalerite measurements). the same analytical conditions were used to obtain the x-ray elemental distribution maps. whole rock geochemical analyses of 3 samples, each representing 10-20 cm long sections of the drillcore, were made in the laboratory of the hungarian geological and geophysical institute. icp-oes was used for major (al2o3, bao, cao, fe2o3, k2o, mgo, mno, na2o, p2o5, sio2, so3, sro and tio2) and some of the trace element analysis (co, cr, cu, ni, v, zn). icp-ms was utilised for other trace elements geologia croatica 66/3geologia croatica 236 figure 3: x-ray elemental distribution maps of framboidal pyrite (cu, fe, au, s, co, zn, ni). compared to the euhedral pyrite overgrowths, it has a slightly higher cu, zn and ni content. (as, rb, y, zr, nb, mo, ag, cd, sn, sb, cs, la, ce, pr, nd, sm, eu, gd, tb, dy, ho, er, tm, yb, lu, hf, ta, w, tl, pb, bi, th, u, pge, au, te and w). lithium borate and aqua regia digestion were used in preparing the samples. the detection limits for the major elements were between 0.0002 % (sro) and 0.2 % (k2o), while for the trace elements it was between 0.05 ppm and 1 ppm (0.05 ppm te, pge; 0.1 ppm zn, cd, tl, ree; 0.2 ppm cu, ag; 0.25 ppm mo, bi, w, u, th, ta, cs, rb, nb; 0.4 ppm ni; 0.5 ppm hf, sn, y, zr; 0.6 ppm as, pb, se; and 1 ppm li, v, sb). 4. results 4.1. the host rock the 100 m studied section of the drillcore is fairly uniform, regarding the rock type. it is composed of marly limestone with shale intercalation and shale beds. the upper part of the studied section, from 900–928 m, is strongly sheared, similarly to the lower part, from 990–1000 m. in spite of this, both zones contain the same rock types. between these two kiss and zaccarini: development of framboidal pyrite in the upper permian marly limestone of the ne-hungarian darnó hill geologia croatica 237 figure 4: x-ray elemental distribution maps of the euhedral pyrite overgrowths (cu, fe, au, s, co, zn, ni). it has practically no cu content, but compared to the framboidal pyrite, significantly more au occurs. tectonized zones, the rock is well preserved. the mineralization occurs in the latter unit. the marly limestone is light grey coloured, at places stylolitic, and is cross-cut by 0.5–3 mm thick calcite veins. in thin section, a mixture of 50–200 µm sized patches, composed of calcite, quartz, rare ferro-dolomite and clay minerals, have been observed. the patches either contain a very fine grained mixture of all these minerals, or can be composed exclusively of calcite or quartz. in some cases, quartz displaces the aforementioned structures, thus later silicification of the marly limestone can be concluded. rare muscovite, zircon, titanite, albite and apatite with a size variable from 10 to 100 µm were also recognized. at least 3 vein generations can be distinguished; the older ones are filled mostly with spongy calcite, while the younger ones are more transparent, and can contain not only calcite, but also a small amount of quartz, dolomite and rare opaque minerals. geologia croatica 66/3geologia croatica 238 table 1: composition of the different ore minerals, based on the epma measurements.   sample fe co ni cu zn ag au pb s as se sb te total eu he dr al p yr ite o ve rg ro w th s o n fra m bo id s ( ag gr eg at es ) 1 47.051 0.086 0.043 b.d.l. b.d.l. 0.064 b.d.l. b.d.l. 53.849 0.129 b.d.l. 0.05 b.d.l. 101.33 2 46.752 0.084 0.024 b.d.l. b.d.l. b.d.l. 0.062 b.d.l. 53.937 b.d.l. b.d.l. b.d.l. 0.076 100.967 3 47.059 0.066 b.d.l. b.d.l. b.d.l. b.d.l. b.d.l. b.d.l. 53.889 0.124 b.d.l. b.d.l. b.d.l. 101.139 4 46.411 0.151 0.022 b.d.l. b.d.l. b.d.l. b.d.l. b.d.l. 53.241 0.37 b.d.l. b.d.l. 0.052 100.302 5 46.689 0.069 b.d.l. b.d.l. b.d.l. b.d.l. 0.067 b.d.l. 53.136 0.263 b.d.l. 0.043 b.d.l. 100.29 6 47.756 b.d.l. b.d.l. b.d.l. b.d.l. b.d.l. 0.156 b.d.l. 53.400 b.d.l. b.d.l. b.d.l. b.d.l. 101.323 7 48.291 b.d.l. b.d.l. b.d.l. b.d.l. b.d.l. b.d.l. b.d.l. 53.696 b.d.l. b.d.l. b.d.l. b.d.l. 102.128 8 47.819 b.d.l. b.d.l. b.d.l. b.d.l. 0.035 0.107 b.d.l. 53.589 b.d.l. b.d.l. b.d.l. b.d.l. 101.583 9 46.162 b.d.l. 0.027 b.d.l. b.d.l. 0.055 b.d.l. b.d.l. 52.032 b.d.l. b.d.l. b.d.l. b.d.l. 98.355 10 47.688 b.d.l. b.d.l. 0.046 0.034 b.d.l. b.d.l. b.d.l. 53.689 b.d.l. b.d.l. b.d.l. b.d.l. 101.471 fr am bo id al p yr ite 1 45.718 0.332 0.296 0.044 b.d.l. b.d.l. b.d.l. 0.401 51.765 0.259 b.d.l. b.d.l. b.d.l. 98.824 2 45.687 0.22 0.066 0.027 0.027 b.d.l. b.d.l. b.d.l. 52.444 0.356 b.d.l. b.d.l. b.d.l. 98.934 3 46.988 0.183 0.051 0.042 b.d.l. 0.091 b.d.l. b.d.l. 53.035 0.249 b.d.l. b.d.l. 0.034 100.716 4 45.967 0.192 0.093 b.d.l. b.d.l. b.d.l. b.d.l. 0.221 52.431 0.253 b.d.l. b.d.l. b.d.l. 99.157 5 46.301 0.189 0.088 b.d.l. b.d.l. b.d.l. b.d.l. b.d.l. 52.819 0.182 b.d.l. b.d.l. 0.041 99.636 6 46.366 0.202 0.079 b.d.l. b.d.l. b.d.l. 0.067 b.d.l. 52.725 0.134 b.d.l. b.d.l. b.d.l. 99.714 7 46.358 0.204 0.072 0.03 b.d.l. 0.044 b.d.l. b.d.l. 52.127 0.073 b.d.l. b.d.l. 0.027 98.954 8 46.686 0.172 0.052 b.d.l. 0.031 b.d.l. 0.067 b.d.l. 52.221 0.243 b.d.l. 0.053 0.029 99.707 9 44.423 0.18 b.d.l. 0.037 b.d.l. b.d.l. b.d.l. 0.265 48.561 0.172 b.d.l. b.d.l. b.d.l. 93.668 10 45.586 b.d.l. 0.039 b.d.l. b.d.l. b.d.l. b.d.l. b.d.l. 52.665 b.d.l. b.d.l. b.d.l. b.d.l. 98.308 11 43.897 b.d.l. 0.093 0.219 b.d.l. b.d.l. 0.087 b.d.l. 48.612 0.077 0.069 0.031 b.d.l. 93.121 12 43.68 4.536 0.36 1.115 b.d.l. b.d.l. b.d.l. b.d.l. 49.261 0.097 b.d.l. b.d.l. b.d.l. 99.744 13 44.896 b.d.l. 0.135 3.212 0.026 0.087 b.d.l. b.d.l. 51.002 0.319 b.d.l. 0.046 b.d.l. 100.176 14 44.762 b.d.l. 0.621 0.262 b.d.l. 0.044 b.d.l. b.d.l. 52.52 0.169 b.d.l. 0.04 b.d.l. 98.507 euhedral pyrite 1 46.178 b.d.l. b.d.l. 0.03 b.d.l. b.d.l. b.d.l. 0.335 51.298 2.065 b.d.l. b.d.l. b.d.l. 99.956 ch al co py rit e 1 29.45 0.041 b.d.l. 34.494 b.d.l. b.d.l. b.d.l. b.d.l. 34.019 b.d.l. b.d.l. b.d.l. b.d.l. 98.103 2 30.156 b.d.l. b.d.l. 34.379 0.047 0.053 b.d.l. b.d.l. 33.921 b.d.l. b.d.l. b.d.l. b.d.l. 98.556 3 29.824 b.d.l. b.d.l. 33.083 0.03 b.d.l. 0.102 b.d.l. 35.247 b.d.l. b.d.l. b.d.l. b.d.l. 98.32 4 33.755 b.d.l. 0.062 21.804 0.043 b.d.l. 0.12 0.139 38.746 b.d.l. 0.04 b.d.l. b.d.l. 94.734 sphale rite 1 0.973 b.d.l. b.d.l. 0.027 63.537 b.d.l. b.d.l. 0.111 30.68 b.d.l. b.d.l. b.d.l. b.d.l. 95.328 b.d.l.: below detection limit, low totals are due to the small size of the analyzed grain the shale intercalations in the marly limestone are dark grey to black in colour, and vary in thickness from 1–2 cm to several tens of centimetres. in general, this rock is strongly tectonized. 4.2. the ore minerals framboidal pyrite is the most abundant ore mineral in the studied samples (fig. 2/1, 3, 4, 6). the framboids are 5–15 µm in size, and are composed of pyrite microcrystals (<1 µm diameter). these spherical phenomena fit well into the framboid definition of ohfuji & rickard (2005). the framboids are disseminated in the marly limestone, with no relation to the stylolites or bedding. the epma analyses revealed that the framboidal pyrite is fairly rich in trace elements. besides the quite common as (up to 0.356 mass%) and ni (up to 0.62 mass%), ag, au, co, cu, pb, sb, se and zn occur also in some samples (0.027–3.212 mass%) (table 1.). the x-ray elemental distribution mapping shows, that these trace elements are distributed uniformly over the framboids (fig. 3.). euhedral pyrite overgrowths on framboidal pyrite form aggregates disseminated in the marly limestone (fig. 2/3, 5). the size of the aggregates is between 25 µm 80 µm, while single pyrite crystals can reach 10 µm. based on the epma analyses, the pyrite of the aggregates is generally less enriched in trace elements, compared to the framboidal pyrite (e.g. as up to 0.263 mass%, ni up to 0.043 mass%, and cu, pb, zn, se do not occur, or are not common) (table 1.). howkiss and zaccarini: development of framboidal pyrite in the upper permian marly limestone of the ne-hungarian darnó hill geologia croatica 239 figure 5: normalized metal content of the studied limestone. a slight enrichment can be observed in the co, cr, cu, ni, v and zn content, while w enrichment can be greater by a factor of 100 (samples are from 933 m, 950 m and 962 m). figure 6: normalized ree content of the studied limestone. in general, the samples are enriched in all the rees, especially in dy and yb (samples are from 933 m, 950 m and 962 m). ever, this type of pyrite contains more au (up to 1500 ppm), than the framboidal one. according to the elemental mapping, au and the other trace elements occur uniformly distributed in these pyrite crystals (fig. 4). in spite of the observed uniform au distribution in the framboidal pyrite and in the euhedral overgrowths, it is possible, that au is present not only as invisible gold in the pyrite structure, but also as nanosized free gold particles. the maximum au concentration, which can be dissolved in the pyrite, depends on its as content according to the equation defined by reich et al. (2005), and the measured au content in the studied framboids is well above this limit. besides the aforementioned common opaque minerals, disseminated euhedral and anhedral pyrite (not forming aggregates or framboids), anhedral chalcopyrite, galena and sphalerite were also recorded (fig. 2/2, 5, 6). they are mostly disseminated in the limestone, in some cases, occurring along the stylolites (fig. 2/2) or within bedding. the disseminated euhedral pyrite is generally 5-20 µm in size, while the size of the anhedral crystals is 50-100 µm. with a few exceptions, chalcopyrite, sphalerite and galena form grains less than 10 µm in size. epma analyses of euhedral pyrite revealed a different composition from the two previously discussed pyrite types; it is characterized with high as (up to 2.065 mass%) and pb (up to 0.335 mass%) content. chalcopyrite is enriched in au (up to 1200 ppm), and contains a small amount of ag, co, ni and zn (0.03–0.06 mass%). due to their small size, few grains of sphalerite were quantitatively analyzed, and only one set of analyses is of good quality. it contains cu, pb and fe as trace elements (0.027–0.973 mass%) (table 1). 4.3. geochemistry whole rock geochemical analyses were carried out on 3 samples, which are representative of the well studied section of the borehole (933.0 m, 950 m and 962.0 m). all the samples represent marly limestone with minor shale intercalations, though the carbonate-siliciclastic rock ratio was obviously slightly different. the variable proportions of the carbonate, marl and shale in the samples is evident in the deviation of cao content (18.3–36.1%) and sio2 content (22.3–57.6%). the 0.7– 1.5 % fe2o3 and mgo contents are controlled by the presence of fe-bearing dolomite, although the fe contribution of the pyrite has to be taken into consideration too (table 2.). the amount of co, cr, cu, v, w and zn exceeds the clark-value of a typical limestone (levinson, 1974), resulting in a characteristic 100-200 ppm total metal content (table 2, fig. 5). this result is much lower, than observations by baksa et al. (1981) from the same borehole. this could have been caused by the fact, that the two sampling methods were entirely different. the samples are characterized by slightly higher zr, th, hf, ti, y and as content in comparison to a typical limestone (levinson 1974), caused by the presence of the accessory zircon, titanite, apatite and as-bearing pyrite, respectively (table 2). on average, the total rare earth element (ree) content of the analysed samples is 50 ppm (table 2), which can be considered as an enrichment in relation to typical limestone (levinson, 1974). if the results are normalized to the avfigure 7: chondrite normalized ree spider diagram of the studied limestone. as a comparison, north american shale composite (nasc) is plotted on the same diagram. the studied marly limestone shows significant similarities to that shale formed under anoxic conditions. geologia croatica 66/3geologia croatica 240 table 2: the results of the geochemical analyses. marly limestone marly limestone marly limestone   1 2 3 1 2 3 1 2 3 rm-131 933 m 950 m 962 m rm-131 933 m 950 m 962 m rm-131 933 m 950 m 962 m al2o3 3.64 3.65 0.983 ag <0.1 <0.1 <0.1 la 12.2 16.2 3.76 bao 0.009 0.012 <0.005 au * * * ce 16.8 25.4 5.53 cao 18.3 36.1 27.7 bi <0.25 <0.25 <0.25 pr 3.07 4.11 0.93 fe2o3 1.06 1.56 0.702 co 11.3 7.42 4.91 nd 12.7 16.9 3.88 k2o 0.681 0.614 <0.20 cr 15.2 15.6 6.26 sm 3.06 3.68 0.98 mgo 1.08 1.29 0.628 cu 10.1 20.2 5.17 eu 0.51 0.76 0.35 mno 0.113 0.157 0.118 ir <0.05 <0.05 <0.05 gd 2.24 2.82 0.93 na2o 0.128 0.542 <0.03 mo 0.52 <0.25 0.57 tb 0.41 0.48 0.17 p2o5 <0.15 <0.15 <0.15 ni 9.21 15.0 2.09 dy 2.56 2.74 1.00 sio2 57.6 22.3 45.0 pb 6.05 5.48 1.92 ho 0.49 0.54 0.20 so3 0.206 <0.15 <0.15 pd <0.05 <0.05 <0.05 er 1.32 1.41 0.51 sro 0.036 0.070 0.056 pt <0.05 <0.05 <0.05 tm 0.19 0.20 0.08 tio2 0.136 0.170 0.041 re <0.05 <0.05 <0.05 yb 1.22 1.22 0.44 results are given in % ru <0.05 <0.05 <0.05 lu 0.19 0.19 0.07 sb 0.11 0.14 0.20 results are given in ppm as 4.68 3.72 3.36 sn 2.52 0.96 1.53 cd 0.15 <0.1 <0.1 te <0.05 <0.05 <0.05 cs 1.11 0.79 0.38 v 27.6 29.1 8.75 hf 1.56 1.30 0.57 w 75.1 24.1 88.2 nb 3.20 4.02 1.02 zn 36.1 22.4 9.91 rb 32.7 27.2 9.06 results are given in ppm ta 0.89 0.74 0.78 th 2.51 2.79 0.71 tl 0.16 <0.1 <0.1 u 0.82 0.51 0.37 y 13.9 16.4 6.49 zr 25.3 23.0 8.44 results are given in % erage ree composition of the limestone (levinson 1974), all the ree display, with a few exceptions, a slight enrichment, with relatively high concentrations of dy and yb (fig. 6.). the chondrite normalized ree diagram shows, that the investigated samples are enriched in all the ree, especially in the light ones (up to 10–100 times) (fig. 7.). two of the studied samples show significant similarities with each other, as well as with the north american shale composite (nasc, gromet et al. 1984), which was plotted for comparison (discussion see below). however, the third analysis is characterized with less enrichment, but a similar pattern, except for the eu value. this is probably caused by the different proportions of the rock forming and accessory minerals. the concentrations of precious metals, such as ag, ir, ru, pt and pd are always below the detection limit, while the measurement of au was reported (table 2.). 5. discussion in the past, framboidal pyrite was thought to be able to form only during diagenesis, by biogenic processes. since then, it has been recognised, that framboidal pyrite may also form during low temperature hydrothermal processes and low grade metamorphism (scott et al. 2009 and references therein). our results show that framboidal pyrite of the studied marly limestone sequence is rich in trace elements and commonly it contains as, cu, co, ni, but au, ag, sb, zn, pb, te kiss and zaccarini: development of framboidal pyrite in the upper permian marly limestone of the ne-hungarian darnó hill geologia croatica 241 figure 8: comparison of the ni and co content of the studied framboidal pyrite and euhedral pyrite overgrowths. it can be clearly seen, that the two pyrite types are characterized by their different composition (empty squares and circles indicate the co or ni content of those crystals, where ni or co content was below the detection limit). and se. according to mitchell (1968), this set of trace elements is typical for those framboidal pyrites, which form during sedimentary processes. raiswell & plant (1980) and large et al. (2009) also agreed with this statement. according to them, these trace elements commonly enrich in the upper part of the sediments, therefore, this local source can play an important role in the composition of the sedimentary pyrite. in the investigated samples, the appearance of the euhedral pyrite aggregates postdates the framboidal pyrite formation. this can be well explained, if the formation criteria of the framboid development are taken into consideration. highly supersaturated fluid is needed for framboidal pyrite formation, but the (pore) fluids can be exhausted rapidly, as fe is very reactive (ohfuji & rickard, 2005). thus, after depleting the local (sedimentary) fe source, transportation from an external source is needed (raiswell & plant, 1980). in conclusion, the transition from the framboidal to the euhedral pyrite aggregates can be interpreted to be a result of the change of the fe source and the fluid. another interpretation could be the recrystallisation of framboids to euhedral pyrite with the progress of diagenesis, as shown by palinkaš (pers comm.) in the case of a lateritic crust in croatia. however, the first option is more supported by the facts as the two pyrite types are characterized by different trace element composition (fig. 8.). the euhedral overgrowths are generally less enriched in trace elements (except for the au content), which is common in pyrite of hydrothermal or metamorphic origin. this change in the trace element content can be caused by several factors, including the metal content of the migrating fluid, or the ability of the trace elements to substitute in the pyrite structure. however, the larger, euhedral crystals were most probably formed more slowly and at higher temperatures than the framboidal pyrite, which can also be a very important factor. this results in a larger grain size, and pyrite crystals with less enriched trace element content. this is due to the fact, that the trace elements most likely partition into separate sulphide phases (e.g. sphalerite, galena, chalcopyrite), rather than become incorporated into the pyrite (large et al., 2009). besides the framboidal and euhedral aggregate pyrite, several other sulphide phases were found in the studied drill core section including disseminated euhedral and anhedral pyrite (which do not form aggregates or framboids), anhedral chalcopyrite, sphalerite and galena. the disseminated pyrite most probably formed from yet another fluid, as it has it’s own different trace element content. however, in contrast to those pyrites, where no relation to any structure was observed, this pyrite type was often related to the stylolites. thus, it can be concluded, that its formation was related to diagenetic processes. the high au content of the studied chalcopyrite grains seems to be typical of this occurrence. though a few nearby localities contain chalcopyrite mineralization, none of them is characterized by a similar composition (fig. 9.). the epigenetic chalcopyrite, which is found in quartz-prehnite veins of low grade metamorphic origin in darnó hill (molnár & kiss, 2013), contains only a few trace elements (e.g. low amount of zn), while chalcopyrite formed in the palaeogene cu-porphyry-epithermal system of recsk (located just 5 km w from the studied locality, see e.g. molnár, 2007 and the references therein) is characterized by it’s typical high zn content (0.1-0.7%). they can also be associated with gold, but lack the other trace elements, which are common in the studied drillcores. therefore, these mineralizations formed under different conditions, although geographically they are located very close to each other. the latter statement was also proven by the composition of the framboidal pyrite. framboidal pyrite was also found in the lejtakna mineralization of the recsk ore field, but it is characterized by a completely different trace element distribution (higher as, pb and zn and lower co content in analyses undertaken for comparison purposes). based on the above discussed trace element distribution, the formation of the framboidal pyrite investigated in this contribution is related to sedimentary processes, while the euhedral pyrite overgrowths and the disseminated sulphides were formed by later fluid migration processes (most likely diagenetic, as no sign of hydrothermal processes was observed). these results allow establishment of more genetic models, as discussed below. figure 9: trace element composition of the studied disseminated chalcopyrite, compared to the analyses of the nearby occurring chalcopyrite ore indications (analyses were carried out by the authors, for comparison purposes) geologia croatica 66/3geologia croatica 242 baksa et al. (1981) found, that the framboids found in the same unit formed most probably during a process similar to the kupferschiefer formation. they came to this conclusion because of the observed synsedimentary (biogenic) characteristics and the stratigraphic position of the host rock. however, several characteristics observed by them were not discovered during our research (e.g. occurrence of the framboids parallel to the bedding, occurrence of the chalcopyrite rim along the margins of the framboids). furthermore, several characteristics, typical of the kupferschiefer, were not observed in our samples (e.g. ag or pge enrichment, occurrence of other characteristic copper minerals). the data presented in this work (e.g. the high au content of the pyrite and the silica replacement of the carbonate), together with the framboid formation display some similarity with the carlin-type au (schroeter & poulsen, 1996), though some important characteristics, like the presence of a very large leaching/alteration zone are missing. however, this option must be considered due to the proximity of the recsk subvolcanic cu-porphyry intrusion, especially because during a complex research programme, a carlin-type au indication was discovered 5 km north of recsk (korpás et al., 1999). recent results on the geology of darnó hill (kovács et al., 2008, kiss et al., 2010, 2012) have proven the occurrence of the neotethyan rifting related environments in several blocks of the mélange, thus geologically the kupfershiefer analogy seem to be a reasonable option. the recorded co, cr, cu, v and zn enrichment fit well into the geochemical signature of the kupferschiefer mineralization (lefebure & alldrick, 1996), and differs significantly from the ones typical of the carlin-type mineralization (schroeter & poulsen 1996, strmić palinkaš et al., 2010). the geochemical features of the investigated samples (together with the other observations, e.g. the mineral paragenesis, the presence of synsedimentary and early diagenetic processes) fit well with the characteristics of the weakly mineralized type of kupfershiefer mineralization defined by vaughan et al. (1989). only the w enrichment is not consistent with the kupferschiefer mineralization. however, large et al. (2011) listed w among the elements, that can be enriched during synsedimentary/early diagenetic processes. according to those authors, several trace elements, initially bonded with organic matter, can be enriched in organic rich muds, from which during synsedimentary/early diagenetic processes, they can partition into the growing pyrite or can form micro inclusions. many of these elements, like mo, v, u, ni, cr, as, and cu are redox-sensitive, therefore their enrichment indicates a reducing, anoxic to euxin marine environment. this fact is also supported by the ree content of the investigated rock, as their amount and distribution is very similar to the north american anoxic shales (gromet et al., 1984, fig. 7). these observations suggest that the geological environment of the studied mineralization is very similar to the kupferschiefer mineralization until now the presence of a weakly mineralized type of the black shale hosted ore mineralization (i.e. only the first mineralization stage) has been verified. the lack of the later stages (average mineralization, ore mineralization and postdiagenetic, structure controlled mineralization, vaughan et al., 1989) can be explained by more models. on one hand, sufficient time is needed for generation of a kupferschiefertype deposit of economic importance (hitzman et al., 2010). if that was not available, then the development of the later mineralization stages was not possible. however, it is possible that any of the later stages developed, but their representatives are not found in the mélange, due to later tectonic processes, which formed the different units and the knappe system of the bükk mts.. last but not least, as this mineralization was discovered ~1 km deep in the crust, in deep drillings, systematic exploration may lead to discovery of the later stages, either here in darnó hill, or at shallower parts of the same tectonic unit in the bükk mts. as kupferschiefer-type mineralization is also known in the geologically correlated dinarides (palinkaš et al., 2008, 2014 in prep.), the latter two options seem to be more probable. 6. summary and conclusions the study on the framboidaland euhedral pyrite overgrowths within the marly limestone of the ne hungarian darnó hill revealed that the rock contains disseminated chalcopyrite, sphalerite and galena. the difference in the trace element composition of the two pyrite types is most probably caused by the difference in their formation processes. the high trace element content of the framboidal pyrite suggests that it formed during synsedimentary processes. in contrast, the euhedral aggregates could have formed from a later diagenetic fluid, concomitantly with chalcopyrite, sphalerite, and galena. thus, at least two steps can be distinguished during the formation of the investigated mineralization. framboidal pyrite occurrence is known in the nearby recsk ore field (palaeogene epithermal and cu-porphyry system, see e.g. molnár, 2007 and the references therein), but based on our results, the connection between the genesis of the two phenomena can be excluded. the observed mineral paragenesis, as well as the trace element content of the ore minerals and the whole rock analyses suggest that the investigated mineralization formed under reducing, anoxic marine conditions. the results presented here support the presence of a weakly mineralized, synsedimentary type black shale hosted base metal mineralization (vaughan et al., 1989). the lack of the later mineralization stages could be the result of either a lack of time for the development of the ore forming processes, destruction by the later tectonic processes or simply requires further exploration. acknowledgement the authors wish to thank é. hartai for fruitful discussions. the university centrum for applied geosciences (ucag) is thanked for access to the e. f. stumpfl electron microprobe laboratory. kiss and zaccarini: development of framboidal pyrite in the upper permian marly limestone of the ne-hungarian darnó hill geologia croatica 243 the work was supported by the aöu (stiftung aktion österreich-ungarn) research grant no. 85öu11 to g. kiss and f. zaccarini. the described work was partly carried out as part of the támop-4.2.2.a-11/1/konv -2012-0005 project as a work of center of excellence of sustainable resource management, in the framework of the new széchenyi plan. the realization of this project is supported by the european union, cofinanced by the european social fund. references aigner-torres, m. & koller, f. (1999): nature of the magma source of the szarvaskő complex (nehungary).− ofioliti, 24, 1–12. baksa, cs., csillag, j., dobosi, g. & földessy, j. (1981): rézpala indikáció a darnó-hegyen (copper shale indication on the darnó hill).− földt. közl., 111, 59–66 (in hungarian with english abstract). boynton, w. v. (1984): cosmochemistry of the rare earth elements: meteorite studies.– in: henderson p. (ed.): rare earth element geochemistry. elsevier, amsterdam, 63–114 csontos, l. (1995): tertiary tectonic evolution of the intra-carpathian area: a rewiev.– acta vul., 7/2, 1–13. csontos, l. (1999): a bükk-hegység szerkezetének főbb vonásai (structure of the bükk mts.).− földt közl, 129/4, 611–651 (in hungarian). dimitrijević, m. n., dimitrijević, m. d., karamata, s., sudar, m., gerzina, n., kovács, s., dosztály, l., gulácsi, z., less, gy. & pelikán, p. (2003): olistostrome/ mélanges – an overview of the problems and preliminary comparison of such formations in yugoslavia and ne hungary.− slovak geol mag, 9/1, 3–21. földessy, j. (1975): petrological study of a diabase-spilit magmatic rock suit, darnó-hegy (sirok, hungary).− proc. xth congr. cbga 1973, 55–64. gromet, p. l., dymek r. f., haskin l. a. & korotec r. l. (1984): the „north american shale composite”: its compilation, major and trace element characteristics. − geochim et cosmochim acta, 48, 2469–2482. haas, j. & kovács, s. (2001): the dinaric-alpine connection—as seen from hungary.− acta geol hung, 44/2–3, 345–362. haas, j., kovács, s., pelikán, p., kövér, sz., görög, á., ozsvárt, p., józsa, s. & németh, n. (2011): a neotethysóceán akkréciós komplexumának maradványai észak-magyarországon (remnants of the neotethyan accretionary complexes in n-hungary).− földt közl, 141/2,167–196 (in hungarian, with english abstract) haidinger, w. (1850): note über das vorkommen von gediegenem kupfer zu recsk bei erlau in ungarn.− jahrb. der geol. reichsan-− jahrb. der geol. reichsanstalt, i, 145–149. harangi, sz., szabó, cs., józsa, s., szoldán, zs., árvasós, e., balla, m. & kubovics, i. (1996): mesozoic igneous suites in hungary: implications for genesis and tectonic settings in the northwestern part of tethys.− int. geol. rev., 38, 336–360 hitzman, m. w., selley, d. & bull, s. (2010): formation of sedimentary rock-hosted stratiform copper deposits through earth history.− econ. geol., 105, 627–639. kiss, g., molnár, f. & palinkaš, l. a. (2008): volcanic facies and hydrothermal processes in triassic pillow basalts from the darnó unit, ne hungary.− geol. croat., 61/2–3, 385–394. kiss, g., molnár, f., †kovács, s. & palinkaš, l. a. (2010): field characteristics and petrography of the advanced rifting related triassic submarine basaltic blocks in the jurassic mélange of the darnó unit.− centr. eur. geol., 53/2–3, 181–204. kiss, g., molnár, f., palinkaš, l. a., kovács, s. & hrvatović, h. (2012): correlation of triassic advanced rifting related neotethyan submarine basaltic volcanism of the darnó unit (ne hungary) with some dinaridic and hellenidic occurrences on the basis of volcanological, fluid-rock interaction and geochemical characteristics.− int. j. earth sci., 101/6, 1503–1521. kiss, j. (1958): ércföldtani vizsgálatok a darnó-hegyen (ore geological studies on the darnó hill).− földt. közl., 88, (in hungarian). korpás, l. a., hofstra, a., ódor, l., horváth, i., haas, j. & zelenka, t. (1999): evaluation of the prospected areas and formation. in: carlin gold in hungary.− geol. hung. ser. geol., 24, 197–293. kovács, s., haas, j., szebényi, g., gulácsi, z., pelikán, p., b.-árgyelán, g., józsa, s., görög, á., ozsvárt, p., gecse, zs. & szabó, i. (2008): permo-mesozoic formations of the recsk-darnó hill area: stratigraphy and structure of the pre-tertiary basement of the paleogene recsk orefield. in: földessy j, hartai é (ed): recsk and lahóca geology of the paleogene ore complex. − geosciences, publications of the university of miskolc, series a, mining, 73, 33–56. †kovács, s., haas, j., ozsvárt, p., palinkaš, l. a., kiss, g., molnár, f., józsa, s. & kövér, sz. (2010): re-evaluation of the mesozoic complexes of darnó hill (ne hungary) and comparisons with neotethyan accretionary complexes of the dinarides and hellenides – preliminary data.− centr. eur. geol., 53/2-3, 205-231. large, r.r., bull, s.w. & maslennikov, v.v. (2011): a carbonaceous sedimentary source-rock model for carlin-type and orogenic gold deposits.− econ. geol., 106, 331–358. large, r. r., danyushevsky, l., hollit, c., maslennikov, v., meffre, s., gilbert, s., bull, s., scott, r., emsbo, p., thomas, h., singh, b. & foster, j. (2009): gold and trace element zonation in pyrite using a laser imaging technique: implications for the timing of gold in orogenic and carlin-style sedimenthosted deposits.− econ. geol., 104, 635–668. lefebure, d.v. & alldrick, d.j. (1996): sediment-hosted cu+/ag+/-co. in: lefebure, d.v. & hõy, t. (eds): selected british columbia mineral deposit profiles, vol. 2 metallic deposits. − british columbia ministry of employment and investment, open file 1996-13, 13–16. levinson, a. a. (1974): introduction to exploration geochemistry.– calgary, canada, applied publishing ltd., 612 p. mezősi, j. & grasselly, gy. (1949): a bajpataki (mátra hgs.) termésréz előfordulás (the occurrence of native copper in the mátra mountains at bajpatak).− acta mineral., petrogr., iii, 44-47 (bilingual paper). mitchell, r.m. (1968): a semi-quantitative study of trace elements in pyrite by spark source mass spectrography.− norsk. geol. tidsskr., 48, 65–80. molnár, f. (2007): the cu-au-ag-zn-pb ore complex at recsk: a uniquely preserved and explored porphyry-skarn-epithermal system. – proceedings of the 9th biannual sga meeting, dublin, ireland, 1: 226–240 molnár, zs. & kiss, g. (2013): study of the epigenetic copper occurrence of the darnó hill and its correlation with some dinaridic and hellenidic occurrences. geoscience meeting and exhibition, abstract book, isbn: 978-693-8221-50-6 ohfuji, h. & rickard, d. (2005): experimental synthesis of framboids – a review.− earth. sci. rev., 71, 147–170. oravecz, j. (1978): az rm-131-es sz. fúrás alaphegységi rétegsorának vizsgálata (stratigraphical study of the rm-131 drilling).− eötvös loránd university, department of geology, manuscript. geologia croatica 66/3geologia croatica 244 palinkaš, l.a., borojević šoštarić, s. & strmić palinkaš, s. (2008): metallogeny of the northwestern and central dinarides and southern tisia.− ore geol. rev., 34, 501–520. palinkaš, l., mavrić, d., bermanec, v., filipović, lj. (2014): copper mineralization within metadolomites in the medvednica mt., nw croatia. (in prep.). raiswell, r. & plant, j. (1980): the incorporation of trace elements into pyrite during diagenesis of black shales, yorkshire, england. − econ. geol., 75, 684–699. reich, m., kesler, s.e., utsunomiya, s., palenik, c. s., chryssoulis, s.l. & ewing, r. (2005): solubility of gold in arsenian pyrite.− geochem et cosmochim acta, 69, 2781–2796. schmid, m. s., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine-carpathian-dinaridic orogenic system: correlation and evolution of tectonic units.− swiss j geosci, 101/1, 139–183. schroeter, t. & poulsen, h. (1996): carbonate-hosted disseminated au-ag.– in: lefebure d.v. & hõy t. (eds): selected british columbia mineral deposit profiles, vol. 2 metallic deposits. − british columbia ministry of employment and investment, open file 1996-13, 9–12. scott, r. j., meffre, s., woodhead, j., gilbert, s. e., berry, r. f. & emsbo, p. (2009): development of framboidal pyrite during diagenesis, low-grade regional metamorphism and hydrothermal alteration.− econ. geol., 104, 1143–1168. strmić palinkaš, s., borojević šoštarić, s., palinkaš, l., pecskay, z., boev.b, bermanec, v. (2010): fluid inclusions and k/ar dating of the allshar au-sb-as-tl mineral deposit, macedonia. geol. macedonica, 24/1, 63–71. vaughan, d. j., sweeney, m., friedrich, g., diedel, r. & haranczyk, c. (1989): the kupferschiefer: an overview with an appraisal of the different types of mineralization.− econ geol, 84, 1003–1027. manuscript received february 08, 2013 revised manuscript accepted september 26, 2013 available online november 06, 2013 caused by enhanced substrate drainage, caused localised changes to the climate, which then caused further change to the vegetation, ultimately resulting in the loss of the wetland (coal swamp) vegetation from much of europe (cleal & thomas, 1999, 2005; hilton & cleal, 2007). the results of igcp 469 indicated that the new biotas adapted to somewhat drier conditions first appeared in the southeast of the study area and then progressively spread westwards. in order to determine how and why this process started, we therefore needed to look further to the south and east, in particular to the area between italy, through the balkan peninsula and northern turkey, and up into the donets basin in ukraine. this is the remit of igcp 575. our aim is to integrate the palaeontological and stratigraphical/sedimentological data from these areas to see what light they throw on this important time in earth history, when we are for the first time getting clear evidence of the interaction between climate and vegetation, not to mention the production of some of europe’s most important energy resources – coal. more on the project can be found on the web site (http:// igcp575.org/index.htm). the second annual meeting of project 575 was held in zagreb, croatia on the 6th and 7th of september 2011, supported by the department of geology, faculty of science, university of zagreb, technically organized by the research team of project 119-1951293-1162 “evidence of biotic and abiotic changes in fossil environments” of the croatian ministry of science, education and sports. a group of twenty scientists from various european countries (uk, netherlands, germany, czech republic, italy, romania, bulgaria, turkey, slovenia and croatia) participated at the meeting. eleven papers originated from presentations at the meeting. all contributions have passed the regular reviewing procedure, since this is a regular volume of geologia croatica although it is predominantly devoted to pennsylvanian ter editorial dear readers, this issue 65/3 of geologia croatica is largely dedicated to the international geosciences program (igcp) project 575 (2010–2015): “pennsylvanian terrestrial habitats and biotas in southeastern europe and northern asia minor and their relation to tectonics and climate”. therefore, besides the usual editor, geologia croatica also has guest-editors prof. jasenka sremac and dr. christopher j. cleal. they have been appointed guest editors for this volume since prof. jasenka sremac from the university of zagreb, croatia was the scientific organiser of the second annual meeting of project 575, and dr. christopher j. cleal from the national museum wales in cardiff, uk. is the overall coordinator of the project. igcp 575 is the successor to an earlier project, igcp 469: “variscan terrestrial biotas and palaeoenvironments”, which looked at changing biotas and palaeoenvironments during moscovian times, mainly focussing on western and central europe and the canadian maritime provinces (cleal et al., 2010, 2011). this suggested that a major change in biotas took place during moscovian times at the same time as there was a drying of the climate, as well as changes to the landscape and drainage patterns linked to variscan tectonic activity. the evidence suggested that there was a feedback process whereby changing vegetation, initially on the international geoscience program (igcp) project 575 – pennsylvanian terrestrial habitats and biotas of southeastern euramerica  doi: 104154/gc.2012.17 geologia croaticageologia croatica geologia croatica 65/3 271–272 zagreb 2012 geologia croatica 65/3geologia croatica 272 restrial biotas. the igcp 575 papers cover a wide range of themes relating to the project. a review of pennsylvanian terrestrial deposits (sremac) is of direct relevance to croatia. there are also general reviews of the pennsylvanian palaeobotany of turkey (cleal & van waveren), italy (ronchi et al.) and slovenia (kolar-jurkovšek & jurkovšek), and a description of a particular flora from romania (popa & cleal); and more detailed treatments of individual taxonomic groups: šimůnek & thomas describe a new selaginella species, tenchov discusses aspects of the ecology of pteridosperm groups, and zodrow & mastalerz use a new approach to identify arborescent lycospids. although palaeobotany is inevitably heavily represent ed, there are also papers covering the palynology of turkey (stolle), and insect trace fossils from croatia (jarzembowski). after “igcp 575” papers there are four other interesting contributions spanning biostratigraphy to petrology issues. faris et al. present nannofosil biostratigraphy of cretaceous to eocene rocks in oman mountains, whereas banak et al. discuss late pleistocene climate history of northeastern croatia. strmić palinkaš et al. analysed fluid inclusions and mineralogy of epidote bearing pegmatite, and slovenec & lugović present petrology and geochemistry of basalts from mt. medvednica (croatia) ophiolite mélange. enjoy the reading. references cleal, c.j., opluštil, s., thomas, b.a. & tenchov, y. (2010): late moscovian terrestrial biotas and palaeoenvironments of variscan euramerica.– netherlands journal of geosciences, 88, 181– 278. cleal, c.j., opluštil, s., thomas, b.a. & tenchov, y. (2011): pennsylvanian vegetation and climate in tropical variscan euramerica.– episodes, 34, 3–12. cleal, c.j. & thomas, b.a. (1999): tectonics, tropical forest destruction and global warming in the late palaeozoic.– acta palaeobotanica, supplement, 2, 17–19. cleal, c.j. & thomas, b.a. (2005): palaeozoic tropical rainforests and their effect on global climates: is the past the key to the present?– geobiology, 3, 13–31. doi: 10.1111/j.1472-4669.2005.00043.x hilton, j. & cleal c.j. (2007): the relationship between euramerican and cathaysian tropical floras in the late palaeozoic: palaeobiogeographical and palaeogeographical implications.– earth-science reviews, 85, 85–116. doi: 10.1016/j.earscirev.2007.07.003 jasenka sremac and christopher j. cleal guest editors, mladen juračić, editor-in-chief  contamination of seabed sediments around a shipyard in the adriatic sea (ugljan island)  hana fajković*, esad prohić* and daniela abramović * department of geology, faculty of science, university of zagreb, horvatovac 95, 10000 zagreb, croatia; (hanaf@geol.pmf.hr; eprohic@geol.pmf.hr; daniela.danci@gmail.com) doi: 10.4154/gc.2012.06 geologia croatica 66/1 77–82 4 figs. 2 tabs. zagreb 2013 geologia croaticageologia croatica ab stra ct geochemical, mineralogical and grain size data from sediment cores in the lamjana bay shipyard were obtained to determine the extent of contamination due to ship refits. the concentration and distribution of ni, pb, cr, zn, cu, mn, cd, as and fe in 9 sediment samples were measured. no increase of the analysed elements above natural background levels was detected, but contamination was not excluded due to possible dilution of seabed sediment by quartz sand used in process of abrasive blasting. keywords: marine sediment, geochemistry, contamination, shipyard, adriatic sea the process of abrasive blasting. the raša river estuary was used not only as a natural model control system to study the accumulation pattern in a similar environment (sondi et al., 1994; 2008), but also for observing the fate of the heavy metal contaminants, studied in this investigation. 2. materials and methods 2.1. sampling four sediment samples were collected with a corer by scuba diving. these were frozen and divided into smaller sub-samples, each 2 cm thick. full depth of each core sample was approximately 30 cm. each core was not analysed in total i.e. not all sub-samples from one core were analysed, but rather only the upper-most part (0–2 cm depth); middle part (6–8 cm depth), and deepest part of the core (13–15 cm depth). all together, nine sub-samples were analysed. water depths where the samples were taken ranged from 8 to 30 m, and all samples were taken along a single line transect 1. introduction lamjana vela bay is located in the southwestern part of ugljan island, one of the islands of the north dalmatia region. ugljan island is the most inhabited island of the zadar archipelago in croatia (magaš & faričić, 2000). the investigated area has been used as a shipyard for ship remounts (repairs) since 1978. the shipyard is located in a natural bay, 300 m wide and up to 30 m deep. the area of interest is shown in figure 1. the surrounding terrain is composed of cretaceous and eocene limestone (majcen et al., 1970). this shipyard has been studied as a source of possible contamination of the seabed sediments as connections between harbour activities and contamination of seabed sediment have been demonstrated in many publications (gibbs & guer ra, 1997; ceulemans et al., 1998; turner, 2010; fato ki & mathabatha, 2001; champ, 2003). as a result of similar activity, the most common alterations in seabed sediments are an increase in toxic metals, harmful organotin compounds from antifouling paints, and quartz sand used in geologia croatica 66/1geologia croatica 78 (fig. 1.). before further analyses, sub-samples were dried at 50°c and homogenized. 2.2. grain-size analysis grain-size analyses were accomplished on all nine dry samples. sediment grain-size distribution was performed by wet sieving using astm standard stainless steel sieves. the internationally accepted classification of sediments (folk, 1954) was used to classify samples. 2.3. mineralogical analysis the mineralogical composition was determined by x-ray powder diffraction (xrd) on a philips x-pert diffractometer using cukα radiation. it was applied to three sub-samples from the core taken in the deepest part of the bay, in 30 m of water. analyses were done on the upper-most part of the core (0–2 cm), middle part of the core (6–8 cm), and deepest part (13–15 cm). the main objective was to identify the mineral composition of the sediment and to see if there were changes connected with the depth of the seabed. 2.4. chemical analysis the size fraction below 63 μm was used for the chemical analyses. nickel, pb, cr, zn, cu, mn, cd, as and fe were determined by aas with a perkinelmer aanalyst700. estimates of total concentrations, or “pseudo-totals”, were determined by digesting with aqua regia, for which a widely used procedure was used, one standardized by iso international standards (iso 11466 1995). results 3.1. grain-size analysis the results of the grain size analysis are shown in a table 1. according to folk’s (1954) sediment classification, five samples were sand; three were muddy sand and only one was slightly gravelly sand (fig. 2.). in all samples, sand was a dominant fraction. the results show an absence of vertical figure 1: geographic location of the study area with the sampling sites. figure 2: folk classification diagram (1954) with the samples according to their analyses. fajković et al.: contamination of seabed sediments around a shipyard in the adriatic sea (ugljan island) geologia croatica 79 change in grain size, but some distinctions between samples were observed. samples with the highest proportion of mud were from the deepest point in the bay. sample jl 5, the one taken closest to the shipyard, cannot be seen as being representative, since the area of sampling was in a zone of shipyard reconstruction where the seabed was covered with concrete blocks. data from a previous investigation of seabed and surface sediments can be found for the kvarner region (juračić et al., 1999), located north of the study area, and so can be used for comparison, with expectancy in similar sediment grain size distribution for both areas. in kvarner region, the prevalent type of sediment is sandy mud, while in lamjana bay it is sand (i.e. muddy sand) in deeper areas of the bay. the differences between these results could be table 1: results of the grain size analysis. sample seabed depth (cm) gravel % sand % mud % sediment type jl 1a 1 0-2 6 89 5 sand jl 1d 2 6-8 12 80 9 sand jl 2a 3 0-2 4 90 6 sand jl 2d 4 6-8 2 86 12 sand jl 2g 5 12-14 1 86 13 sand jl 3a 6 0-2 ⁄ 77 23 muddy sand jl 3d 7 6-8 1 76 23 muddy sand jl 3h 8 12-14 2 73 25 muddy sand jl 5 9 0-2 17 79 4 slightly gravelly sand figure 3: distribution of elements in accordance with depth and sample locations. geologia croatica 66/1geologia croatica 80 connected with the process of abrasive blasting during shipyard activities, in which tonnes of quartz sand were used, which ended up in the bay. 3.2. results of mineralogical analysis the results of the three analysed samples were uniform. subsamples were taken from one core, and vertical variation was not observed. in all samples quartz, calcite and aragonite were determined. after analysis of the bulk mineralogical composition, the samples were treated with hcl (1:5) to dissolve the carbonate components, after which they were again analysed. when carbonate components were removed, quartz, mica and plagioclase minerals were detected. 3.3. results of chemical analysis the chemical analysis for “pseudo-total” concentrations of the observed elements (ni, pb, cr, zn, cu, mn, cd, as and fe) and their distribution are presented in fig. 3. the results can be divided into two groups. the first group consists of elements ni, cr and as. these elements show uniformity (horizontal and vertical); the concentration of certain elements does not change considerably with the depth, with a mean value for ni, cr and as as follows: 14.9 ± 2.68, 23.5 ± 2.70 and 8.6 ± 2.92 mg/kg. in the second group, the elements include pb, zn, cu, mn, cd and fe with a mean value: 13.9 ± 4.64, 41.7 ± 12.43, 27.8 ± 8.49, 82.9 ± 12.52, 0.2 ± 0.12 mg/ kg; 0.8 ± 0.15 %, respectively. these show differences in concentration according to the depth of the sub-sample, as well as a lateral difference i.e. differences between samples. 4. discussion geochemical results are often hard to interpret, due to the com plexity of seabed genesis, anthropogenic impact and frequent absence of background information. there is no previous analysis of the study area, though two studies (ob hođaš & valković, 2010; dolenc et al., 1998) provide a frame of reference from which to work. obhođaš & valković (2010) published natural background values for concentrations of chemical elements in coastal sediments of the eastern adriatic sea, calculated from 101 samples in the region. dolenc et al. (1998) reported measurements of major, minor and trace elements for 35 locations in the adriatic. their “sample 70” best compares with the location of lamjana bay. results from these two publications were used to indicate possible natural background values for lamjana bay as they are the most suitable according to location and proximity. sondi et al. (1994, 2008) indicated the possibility of contaminants bound to particles, mostly heavy metals, such as strong adsorption to clay minerals, and their organic coating. the basic statistical parameters of measured elements (ni, pb, cr, zn, cu, mn, as, fe and cu) from all samples are presented in table 2. the concentrations of all elements of interest in lamjana bay, except cu, are within the background range and no amplification from natural background values was detected. the higher value of cu in the sediments can be due to the use of anti-fouling paints in the shipyard, which up until the late 1960s were almost invariably copper based (walker et al., 2005). from these results, it can be concluded that the shipyard only has a negative influence on sediment with respect to an increase in the cu value. still, it should be kept in mind that the large quantity of quartz sand used in the process of abrasive blasting may have diluted sediment pollution, as has already been noticed (kennicutt et al. 1996). further, while analysing the results of chemical analysis, it should be considered that the quartz dilution depends on its content in the <63 μm fraction, in which it has been detected. obhođaš & valković (2010) investigated both natural background values and concentrations of chemical elements in sediments around a marina service area. as presumed, the concentration of analysed elements in the marina service area was several orders of magnitude greater than the background values. the element showing the least increase was arsenic. its concentration in the sediment of the marina service area is table 2: basic statistical parameters of ni, pb, cr, zn, cu, mn, as and cu expressed in mg/kg; fe expressed in %. n – number of results, x – mean value, sd – standard deviation. statistical parameter ni pb cr zn cu mn as cd fe * n 9 9 9 9 9 9 9 9 9 x (mg/kg) 14.87 13.91 23.51 41.68 27.77 82.89 8.63 0.22 0.76 sd (mg/kg) 2.68 4.64 2.70 12.43 8.49 12.52 2.92 0.12 0.15 min. (mg/kg) 9.68 5.98 19.65 25.70 17.73 63.30 2.90 0.03 0.48 max. (mg/kg) 18.63 19.80 27.30 68.28 45.60 100.70 12.08 0.35 1.01 median (mg/kg) 14.50 12.93 23.15 38.53 29.13 85.15 8.83 0.23 0.76 o. & v. (a) 15.50 9.80 43.90 33.60 16.20 75.60 6.60 / / o. & v. (b) / 249.00 / 2777.40 3467.90 / 95.70 / / d. et al. 34.00 27.00 73.00 64.00 15.00 242.00 9.00 / 1.79 * statistical parameters for fe are expressed in % o. & v. (a) – natural background values from obhođaš and valković (2010) o. & v. (b) – values from marine service areas from obhođaš and valković (2010) d. et al. – natural background values. location "v70" from dolenc et al. (1998) fajković et al.: contamination of seabed sediments around a shipyard in the adriatic sea (ugljan island) geologia croatica 81 14.5 times the natural background values. with an assumption that pollution levels will be similar in similar conditions (a marina service area), it is possible to estimate the amount that the quartz debris diluted the pollution levels. from the value of as (95.7 mg/kg) in the marine pier service area (obhođaš & valković, 2010) and that recorded in lamjana bay (8,63 mg/kg), the dilution of seabed sediment by quartz could be determined. the estimated values and that recorded in lamjana bay differ by one order of magnitude. it follows from these results that the values of the other observed elements are also one order of magnitude greater in terms of their input into the environment, but due to the high amount of quartz, the recorded values are lower. results of the sampled sediment from lamjana bay do not vary significantly from the natural background values; hence the sediment could be considered as unpolluted. but if the measured values are enlarged by one order of magnitude (the assumed dilution factor), then the situation is rather different. in that scenario, the value of lead, iron, copper, and zinc would be greater than the natural background value, which can be connected to the shipyard and quantity of abrasives used in the refurbishing process (alebic-juretic & matkovic, 2000; singh & turner, 2009). figure 4 shows a comparison of the measured values (mean) with the different international values for sediment quality criteria, which show the range in which sediments in seawater are considered uncontaminated, moderately contaminated and highly contaminated (chapman et al., 1999). concentrations below the grey field are unlikely to have adverse biological effects, and concentrations above the grey field are very likely to have severe adverse biological effects. the grey zone can be observed as suitable for open water marine disposal (chapman et al., 1999). the range is large since it is a comparison of different international values. all values of the analysed elements from lamjana bay sediments, except pb, are in the lower part of the “moderately contaminated” range, and for one shipyard environment, these results are satisfactory. 5. conclusons geochemical analyses of sediments from the studied shipyard are showing values commensurate with a range of a background values. nevertheless, a conclusion of no pollution from the shipyard activities should be made with caution due to the high amount of quartz used with the ship refitting and its subsequent dilution effect on the seabed sediment. acknowledgement this study was supported by the project “geochemical model of transport of contaminants around waste disposal facilities” (119-0831529-1161) funded by the ministry of science, education and sports of the republic of croatia. the authors would like to thank to stephanie kramer for her suggestions and help with the paper. references alebic-juretic, a. & matkovic, n. (2000): airborne metal concentrations in shipyard environment.– arh hig rada toksikol, 51, 249–256. ceulemans, m., slaets, s. & adams, f. (1998): speciation of organotin in environmental sediment samples.– talanta, 46, 395– 405. doi: 10.1016/s0039-9140(97)00403-7 chapman, p.m., allard, p.j. & vigers, g.a. (1999): development of sediment quality values for hong kong special administrative region: a possible model for other jurisdictions.– marine pollution bulletin, 38, 161–169. doi: 10.1016/s0025-326x(98)00162-3 chapman, p.m. & mann, g.s. (1999): sediment quality values (sqvs) and ecological risk assessment (era).– marine pollution bulletin, 38, 339–344. doi: 10.1016/s0025-326x(99)00033-8 champ, m.a. (2003): economic and environmental impacts on ports and harbors from the convention to ban harmful marine anti-fouling systems.– marine pollution bulletin, 46, 935–940. doi: 10.1016/ s0025-326x(03)00106-1 dolenec, t., faganeli, j. & pirc, s. (1998): major, minor and trace elements in surficial sediments from the open adriatic sea: a regional geochemical study.– geol. croat., 51/1, 59–73. fatoki, o.s. & mathabatha, s. (2001): an assessment of heavy metal pollution in the east london and port elizabeth harbours.– water sa, 27/2, 233–240. folk, r.l. (1954): the distinction between grain size and mineral composition in sedimentary rock nomenclature.– journal geology, 62, 344–356. doi: 10.1086/626171 gibbs, r.j. & guerra, c. (1997): metals of the bottom muds in belize city harbor, belize.– environmental pollution, vol. 98/1, 135– 138. doi: 10.1016/s0269-7491(97)00092-4 iso 11466 (1995): soil quality – extraction of trace elements soluble in aqua regia. figure 4: the range of world-wide sediment quality values (moderately contaminated sediments) for selected metals and a metalloid (grey zone) (chapman & mann, 1999), with the mean value of observed elements (black dot), and one order of magnitude amplified values (white dot). geologia croatica 66/1geologia croatica 82 juračić, m., benac, c. & crmarić, r. (1999): seabed and surface sediment map of the kvarner region, adriatic sea, croatia (lithological map, 1:500,000).– geol. croat., 52/2,131–140. kennicutt, ii m.c., boothe, p.n., wade, t.l., sweet, s.t., rezak, r., kelly, f.j., brooks, j.m., presley, b.j. & wiesenburg, d.a. (1996): geochemical patterns in sediments near offshore production platforms.– can. j. fish. aquat. sci., vol. 53, 2554–2556. doi: 10.1139/f96–214 krauskopf, k.b. (1979): introduction to geochemistry (2nd edition): new york, mcgraw-hill. magaš, d. & faričić, j. (2000): geographical elements of the ugljan island development.– geoadria, vol. 5, 49–92. majcen, ž., korolija, b., sokač, b. & nikler, l. (1973): osnovna geološka karta sfrj 1:100000. tumač za list zadar k 33– 139 [basic geological map of sfry 1:100000, geology of the zadar sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd, 40 p. majcen, ž., korolija, b., sokač, b. & nikler, l. (1970): osnovna geološka karta sfrj 1:100000, list zadar k 33–139 [basic geological map of sfry 1:100000, zadar sheet – in croatian]. – geološki zavod, zagreb, savezni geološki zavod, beograd. prohić, e. & kniewald, g. (1987): heavy metal distribution in recent sediments of the krka river estuary-an example of sequential extraction analysis.– mar. chem., 32, 279–297. doi: 10.1016/03044203(87)90015-6 pikelj, k., žigić, v. & juračić, m. (2009): origin and distribution of surface sediments in the grgur channel, adriatic sea, croatia – geol. croat., 62/2, 95–105. doi: 10.4154/gc.2009.08 obhođaš, j. & valković, v. (2010): contamination of the coastal sea sediments by heavy metals.– applied radiation and isotopes, 68, 807–811. doi: 10.1016/j.apradiso.2009.12.026 singh, n. & turner, a. (2009): trace metals in antifouling paint particles and their heterogeneous contamination of coastal sediments.– marine pollution bulletin, 58, 559–564. doi: 10.1016/j. marpolbul.2008.11.014 sondi, i., lojen, s., juračić, m. & prohić, e. (2008): mechanisms of land–sea interactions – the distribution of metals and sedimentary organic matter in sediments of a river-dominated mediterranean karstic estuary.– estuarine, coastal and shelf science, 80, 12–20. doi: 10.1016/j.ecss.2008.07.001 sondi, i., juračić, m., prohíć, e. & pravdić, v. (1994): particulates and the environmental capacity for trace metals: a small river as a model for a land-sea transfer system: the raša river estuary.– science of the total environment, 155, 173–185. doi: 10.1016/0048-9697(94)90290-9 turner, a. (2010): marine pollution from antifouling paint particles.– marine pollution bulletin, 60, 159–171. doi: 10.1016/j.marpolbul.2009.12.004 walker, g.m., hanna, j.a. & allen, s.j. (2005): treatment of hazardous shipyard wastewater using dolomitic sorbents.– water research, 39, 2422–2428. doi: 10.1016/j.watres.2005.04.025 manuscript received february 22, 2012 revised manuscript accepted january 17, 2013 available online february 28, 2013 strmić palinkaš et al.: the evolution of the čanište epidote-bearing pegmatite, fyro macedonia: evidence from mineralogical and geochemical features 423  geologia croatica 65/3 423–434 7 figs. 5 tabs. zagreb 2012 the evolution of the čanište epidote-bearing pegmatite, republic of macedonia: evidence from mineralogical and geochemical features  sabina strmić palinkaš1, vladimir bermanec1, ladislav a. palinkaš1, blažo boev2, robert a. gault3, walter prochaska4, ronald j. bakker4 1 institute of mineralogy and petrology, department of geology, faculty of science, university of zagreb, horvatovac 95, hr-10000 zagreb, croatia; (sabina.strmic@inet.hr) 2 faculty of mining, geology and polytechnic, goce delčev university, krste misirkov bb, p.o. box 201, mk-2000 štip, republic of macedonia 3 research division, canadian museum of nature, p.o. box 3443, station d, ottawa, ontario k1p 6p4, canada 4 department of applied geosciences and geophysics, mineralogy and petrology group, university of leoben, peter-tunner-strasse 5, a-8700 leoben, austria doi: 104154/gc.2012.31 geologia croaticageologia croatica ab stra ct the epidote-bearing čanište pegmatite and adjacent upper carboniferous granodiorites cut precambrian gneisses, on the western slopes of the selečka mts., the eastern pelagonian zone, republic of macedonia. the pegmatite exhibits zonal internal structure with the following sub-units: the wall zone (amazonite microcline ± biotite, quartz), the first intermediate zone (epidote + haematite + grossular + muscovite + quartz + almandine ± zircon, beryl, microcline, quartz), the second intermediate zone (albite + quartz ± microcline) and the core (massive quartz). according to the microprobe data epidote belongs to clinozoisite subgroup with the formula (ca1.96–1.99mn0.02–0.03fe2+ 0.00–0.02) (al2.17–2.46fe3+ 0.51–0.82ti0.00–0.01)(si2o7)(si0.99–1.00al0.00–0.01o4)o(oh). the occurrences of almandine and zircon with low u, th and ree content, are indicative of weakly evolved granitic/granodioritic rocks. the absence of aplites suggests steady pressure conditions during the course of pegmatite crystallization. microthermometric data combined by the two-feldspar geothermometer gained pressure from 4.8 to 5.6 kbar for the second intermediate zone. the wall zone, composed of amazonite microcline, crystallized at a temperature between 650 and 760 °c. a drop in melt temperature to below 550 °c, under the oxygen fugacity between 10–22 and 10–19.5 bar, was the principal trigger for crystallization of minerals in the first intermediate zone. the residual fluid, depleted in ca, fe and k, and enriched in water, na and si, caused deposition of the second intermediate zone (albite + quartz) at temperatures between 445 and 465 °c. the massive quartz core crystallized in the very last stage of the pegmatite evolution (t ≈ 400–480 °c) from melt residue enriched in silica, water and co2 content. keywords: magmatic-hydrothermal transition, granodiorite, pegmatite, epidote, fluid inclusions, pelagonian zone, republic of macedonia 1. introduction the čanište pegmatite is situated approximately 150 km south of skopje, republic macedonia, on the western slopes of the selečka mts. which represent a part of the eastern pelagonian tectono-stratigraphic unit of the dinaride-hellenides (fig. 1). the pelagonian massif exposes precambrian crystalline basement made of orthoand paragneisses, micaschists and amphibolites and comprises numerous pegmatites, which differ according to their size, mineralogical feageologia croatica 65/3geologia croatica 424 figure 2: paragenetic sequence of the čanište epidote-bearing pegmatite. tures, internal structures and the degree of fractionation (e.g. ivanov et al., 1966; zebec & radanović-gužvica, 1992; jovanovski et al., 2003). this pegmatite attracts attention due its peculiar ca-enriched mineral assemblage with the unique occurrence of up to 2 metre long epidote crystals (bermanec et al., 2001). epidote is not a common pegmatitic mineral and it has been recorded only within several epidote-bearing pegmatites elsewhere (e.g. franz & smelik, 1995; janeczek, 2007, liebscher et al., 2007; cota et al., 2010, swanson & veal, 2010). furthermore, the čanište pegmatite exhibits a zonal mineral distribution that allows a detailed investigation of fluid inclusions within minerals from the different stages of the pegmatite crystallization. although the zonal pegmatites are common, and fluid inclusions represent relicts of fluids involved in the crystallization processes, only a few publications present the fluid inclusion data systematically collected across the distinct pegmatite zones (e.g. london, 1986, 1990; thomas & spooner, 1988, 1992; fuertes-fuente et al. 2000; beurlen et al., 2001; sirbescu et al., 2008). the pegmatites are related to the late stage of magmatic crystallization. while the importance of volatiles and incompatible elements in enriched melts is generally accepted, there are still numerous open questions about the mechanism of their deposition. the majority of authors consider that water-saturated magmas are responsible for the principal mineralogical characteristics of pegmatites (e.g. jahns & burnham, 1969; burnham & nekvasil, 1986; nabelek et al., 2010). in contrast, london et al. (1989) figure 1: geological setting of the čanište epidote-bearing pegmatite, republic of ma cedonia (after most, 2003). wmz – wes tern macedonian zone; pm – pelagonian mas sif; vz – vardar zone; smm – serbo-ma cedonian massif. strmić palinkaš et al.: the evolution of the čanište epidote-bearing pegmatite, fyro macedonia: evidence from mineralogical and geochemical features geologia croatica 425 figure 3: a) photomicrographs of microcline from the wall zone; b) the transition from the first intermediate zone comprising epidote, hematite, muscovite and quartz into the second intermediate zone with albite and quartz. abbreviations: ab – albite; ep – epidote; hem – hematite; mic – microcline; ms – muscovite; qtz – quartz. and london (1990, 2008) explain the formation of pegmatites by disequilibrium crystallization from water unsaturated magmas, emphasizing the role of fluxing elements such as b, f, and p. the aim of this study is to interpret the evolution of meltfluid in the late magmatic system responsible for deposition of the čanište epidote-bearing pegmatite. a fluid inclusion study complemented by calculated thermodynamic equilibria of the mineral paragenesis shed light on the p-t-x conditions when the pegmatite formed. 2. geological setting the pelagonian tectono-stratigraphic unit is a ca. 420 km long and 60 km broad in the nnw-sse striking part of the central hellenides (fig. 1), exposing precambrian crystalline basement made of orthoand paragneisses, micaschists and amphibolites. granitoids intruded the pelagonian basement during: i) upper carboniferous and ii) late permian – early triassic magmatic events (most, 2003). according to the qap classification, pelagonian granitoids range from granite to quartz-diorite, but are mainly granodioritic in composition (dumurdzanov, 1985; most, 2003). the upper carboniferous granodiorite (299 ± 1 ma, u/pb zircon age dating; most, 2003) underwent compressional deformation and developed a greenschist to amphibolite-grade metamorphic overprint. a late permian – early triassic granodiorite (~245 ± 1 ma, u/pb zircon age dating; most, 2003) is represented by massive intrusive bodies within the eastern pelagonian zone, including the selečka mts. the relicts of concomitant metamorphism are not preserved. a sedimentary sequence, comprising carbonate and clastic rocks, was deposited during triassic and jurassic times. the geological structure of the pelagonian zone is mostly a consequence of polyphase tectonometamorphic events during convergence of the apulian and european plates between the upper jurassic and upper tertiary times (most, 2003). the čanište pegmatite is one of numerous pegmatite occurrences within the eastern pelagonian zone. the pegmatites vary in size from a few decimetres wide and tens of metres long to larger bodies tens of metres wide by hundreds of metres long. they differ according to the mineralogical features, the internal structures and the fractionation degree as well. beside epidote-bearing ones (čanište and dunje localities), the most interesting are those enriched in uranium and thorium mineralization (alinci and crni kamen localities; e.g. ivanov et al., 1966; radusinović & mark ov, 1971; bermanec et al., 1988, 1992; zebec & radanović-gužvica, 1992). the čanište lens-shaped, up to 10 m wide pegmatite body, cuts precambrian gneisses (dumurdzanov, 1985; most, 2003). the well developed internal zonation of the pegmatite is illustrated by an idealized paragenetic sequence (fig. 2). equigranular subhedral amazonite microcline is the main constituent of the wall zone (fig. 3a), whereas quartz and biotite are accessory minerals. the first intermediate zone consists of giant epidote crystals (up to 2 m long; fig. 3b), microcline, haematite, muscovite, garnet, quartz, and minor zircon and beryl (fig. 3c). the second intermediate zone, composed of albite, quartz and minor microcline grades (fig. 3c) into the monomineralic massive quartz core. 3. analytical methods feldspar, epidote, quartz, garnet and zircon crystals were separated for x-ray powder diffraction (xrd) and electronmicroprobe analyses. the xrd analyses were conducted on oriented samples using a philips diffractometer pw 3040/60 x’pert pro (45 kv, 40 ma) with cukα monochromatised geologia croatica 65/3geologia croatica 426 radiation (λ=1.54056 å) and θ-θ geometry. samples were scanned between 4 and 63 ° 2θ with 0.02 ° step per 0.5 minute. the goniometer was calibrated against a quartz standard. phase identification was performed using x’pert highscore software package (pananalytical, 2004) in support with icdd-pdf 2 database (2004). unit cell parameters were calculated with the least-square refinement program unitcell (holland & redfern, 1997). the chemical composition of selected samples was estimated by the jeol 733 electron microprobe equipped with the tracor northern 5500 and 5600 automation. an accelerating voltage of 15 kv and a beam current of 20 na were used in the analyses. beam diameter varied with the mineral phase analyzed: 2 mm for zircon, garnet and epidote and 20 mm for feldspars. the following standards were used: albite (na, al, si), sanidine (k), gehlenite (ca), almandine (fe), rutile (ti), tephroite (mn), zircon (zr), diopside (mg), sanbornite (ba), rubidium microcline (rb), pollucite (cs), crocoite (pb), synthetic ree phosphates (la, ce, pr, nd, sm, gd, er, yb), synthetic yttrium iron garnet (y), synthetic hafnon (hf), synthetic uo2 (u) and synthetic tho2 (th). minimum detection limits for all analyzed range from 200 to 300 ppm. fluid inclusion investigations were carried out on microcline, albite, epidote and quartz crystals. microthermometric measurements of fluid inclusions were performed using a linkam thms 600 stage mounted on an olympus bx 51 microscope using 10x and 50x olympus long-working distance objective lenses for visible light. two synthetic fluid table 1: representative microprobe analyses, calculated formulas and distribution of the key cation sites for epidote from the first intermediate zone of the čanište epidote-bearing pegmatite. pt 1 pt 2 pt 3 pt 4 pt 5 pt 6 pt 7 pt 8 pt 9 chemical composition (wt. %) sio2 36.82 36.74 37.36 36.86 36.79 36.88 37.45 37.07 37.66 tio2 < d.l. 0.09 < d.l. 0.08 < d.l. < d.l. 0.09 0.07 0.12 al2o3 22.98 22.80 22.84 22.50 22.63 22.57 26.19 24.33 26.10 fe2o3 12.87 13.06 13.06 13.11 13.33 13.07 8.90 11.20 8.78 mno 0.44 0.41 0.44 0.55 0.49 0.49 0.25 0.36 0.25 cao 22.64 22.73 22.78 22.77 22.62 22.36 23.32 22.99 23.17 h2o** 1.84 1.84 1.85 1.84 1.84 1.83 1.88 1.86 1.88 tot 97.59 97.67 98.33 97.71 97.70 97.20 98.08 97.88 97.96 structural formula (atom. %) si4+ 3.00 2.99 3.02 3.00 3.00 3.02 2.99 2.99 3.01 ti4+ 0.00 0.01 0.00 0.00 0.00 0.00 0.01 0.00 0.01 al3+ 2.21 2.19 2.18 2.16 2.17 2.18 2.46 2.31 2.46 fe3+ 0.79 0.80 0.78 0.80 0.82 0.78 0.53 0.68 0.51 fe2+ 0.00 0.00 0.02 0.00 0.00 0.02 0.00 0.00 0.02 mn2+ 0.03 0.03 0.03 0.04 0.03 0.03 0.02 0.02 0.02 ca2+ 1.98 1.98 1.97 1.99 1.98 1.96 1.99 1.99 1.98 cats 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 distribution of ions on key sites a1 mn2+ 0.03 0.03 0.03 0.04 0.03 0.03 0.02 0.02 0.02 fe2+ 0.00 0.00 0.02 0.00 0.00 0.02 0.00 0.00 0.02 ca2+ 0.97 0.97 0.95 0.96 0.97 0.94 0.98 0.98 0.97 a2 ca2+ 1.01 1.01 1.02 1.03 1.01 1.02 1.01 1.01 1.02 m1 al3+ 0.99 0.99 0.95 0.97 0.99 0.96 0.99 0.99 0.98 m2 al3+ 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 m3 fe3+ 0.79 0.80 0.78 0.80 0.82 0.78 0.53 0.68 0.51 ti4+ 0.00 0.01 0.00 0.00 0.00 0.00 0.01 0.00 0.01 al3+ 0.21 0.19 0.22 0.19 0.18 0.22 0.46 0.32 0.48 t si4+ 3.00 2.99 3.02 3.00 3.00 3.02 2.99 2.99 3.01 al3+ 0.00 0.01 0.00 0.00 0.00 0.00 0.01 0.01 0.00 < d.l. – below detection limit * total iron content given as fe2o3 k, na and mg are below detection limits ** determined by stoichiometry strmić palinkaš et al.: the evolution of the čanište epidote-bearing pegmatite, fyro macedonia: evidence from mineralogical and geochemical features geologia croatica 427 inclusion standards (syn flinc; pure h2o and mixed h2oco2) were used to calibrate the equipment. the precision of the system was ±2.0 °c for homogenization temperature, and ±0.2 °c in the temperature range between –60 and +10 °c. the laser raman spectroscopy, used for the semiquantitative analysis of co2 and n2 in the co2-rich phases of fluid inclusions, was performed on the dilor labram instrument. a laser beam is focused through an olympus bx 40 microscope onto the fluid inclusion of interest. the objective lenses of 50x and 100x magnification, combined with a confocal optical arrangement, enable a spatial resolution in the order of a cubic micrometer. frequency-doubled ndyag green laser (532 nm, 100 mv) was employed. measurements can also be performed at temperature range between –190 and 600 °c, using the linkam thmsg 600 heating-cooling stage described above. bulk ion compositions of fluid inclusions were established by ion chromatographic analysis applying the technique modified after bottrel et al. (1988). about 1 g of cleaned grains and 5 ml of double-distilled and de-ionized water were ground with an agate mortar and pestle to fine powder. the milky solution produced was centrifuged to separate the leachate from the sample. a dionex dx-500 system with a micromembrane suppressor and pulsed amperometric detector was used for analyses of anions and cations. detection limits are in the 0.1 ppb (mg/l) range. 3. results 3.1. mineralogy and chemical composition of minerals the wall zone consists of amazonite microcline with the following unit cell characteristics a= 8.348(5) å, b = 13.333(8) å, c = 7.062(5) å, α = 91.15(7)°, β = 116.25(9)°, γ = 88.22 (1)° and v = 720.56(3) å3. minor biotite and quartz occur as well. the first transitional zone represents mineralogically the most diverse unit of the čanište pegmatite. it comprises euhedral columnar crystals of epidote, up to 2 m long, embedded in a mediumto coarse-grained matrix of haematite, muscovite, quartz, albite, microcline and garnet. zircon and beryl grains occur sporadically. the epidote lattice parameters, calculated on the basis of xrd patterns, (a= 8.890(2) å, b = 5.634(2) å, c = 10.147 (2) å, β = 115.40(2)° and v = 459.1(2) å3) correspond well to the data previously reported for epidote from other localities (e.g. bonazzi & menchetti, 1995). according to the electron-microprobe data (table 1) and classification proposed by armbruster et al. (2006), epidote from the čanište pegmatite belongs to the clinozoisite subgroup with a general formula of ca2al2fe3+(si2o7)(sio4)o(oh). the structural formula and the key cation sites calculated on the basis of σ(a+m+t)=8 are listed in table 1. garnet crystals are not very common. they vary in size, reaching up to 2 cm and have a deep red color. the cell parameters, calculated from diffraction lines using the leastsquares method, are a = 11.713(2) å and v = 1607(1) å3. the molar proportions of garnet end-members were calculated from the electron microprobe data (table 2) according to the procedure published by locock (2008). grossular, with 39.9 – 40.7 mole %, represents the principal garnet contable 2: representative microprobe analyses, calculated formulas, distribution of the key cation sites and the end-member contents for garnets from the first intermediate zone of the čanište epidote-bearing pegmatite. pt 1 pt 2 pt 3 chemical composition (wt. %) sio2 37.00 37.38 37.14 tio2 0.35 0.36 0.32 al2o3 20.07 20.18 19.97 fe2o3 1.65 1.56 1.71 feo 16.87 16.67 16.66 mno 6.91 6.57 6.70 cao 15.98 15.94 15.75 mgo 0.27 0.29 0.30 tot 99.10 98.95 98.55 structural formula (atom. %) si4+ 2.97 3.00 2.99 ti4+ 0.02 0.02 0.02 al3+ 1.90 1.91 1.90 fe3+ 0.10 0.09 0.10 fe2+ 1.13 1.12 1.12 mn2+ 0.47 0.45 0.46 ca2+ 1.38 1.37 1.36 mg2+ 0.03 0.04 0.04 cats 8.01 7.98 7.99 o 12 12 12 distribution of ions on key sites x fe2+ 1.12 1.12 1.13 mn2+ 0.47 0.45 0.46 ca2+ 1.38 1.37 1.37 mg2+ 0.03 0.03 0.04 y ti4+ 0.02 0.02 0.02 al3+ 1.87 1.88 1.88 fe3+ 0.10 0.09 0.10 fe2+ 0.01 0.00 0.00 z si4+ 2.97 3.00 2.99 al3+ 0.03 0.00 0.01 the end-members content (mole %) spessartine 15.9 15.2 15.5 pyrope 1.1 1.2 1.2 almandine 38.0 38.1 38.1 grossular 39.9 40.7 40.0 andradite 5.1 4.8 5.2 geologia croatica 65/3geologia croatica 428 table 3: representative microprobe analyses and calculated formulas for zircon from the first intermediate zone of the čanište epidote-bearing pegmatite. zircon pt 1 pt 2 pt 3 chemical composition (wt. %) zro2 64.73 64.83 64.93 hfo2 2.71 2.79 2.81 sio2 32.36 32.50 32.46 tot 99.80 100.12 100.20 structural formula (atom. %) zr4+ 0.976 0.974 0.975 hf4+ 0.024 0.025 0.025 si4+ 1.000 1.001 1.000 cats 2.000 2.000 2.000 o 4 4 4 y, la, ce, pr, nd, sm, gd, er, yb, ti, th and u are below detction limits. stituent. the proportion of almandine is estimated within a range between 38.0 and 38.1 mole %. spessartine content spans between 15.2 and 15.9 mole %. andradite and pyrope contents vary up to 5.2 and 1.2 mole %, respectively. pinkish, several cm long, zircon crystals display the following unit cell parameters: a = 6.811(4) å, b = 5.988(6) å and v = 261.7(3) å3. its chemical composition and structural formula, calculated on the basis of four atoms of oxygen per formula unit, are summarized in table 3. albite and quartz represent the principal constituents of the second transitional zone. amazonite microcline occurs sporadically. blocky white albite occurs in the form of crystals up to 10 cm in size. the unit cell parameters, calculated from diffraction lines using the least-squares method, are a= 8.142(6) å, b = 12.784(3) å, c = 7.165(4) å, α = 94.158(9)°; β = 94.158(9)°, γ = 87.741(0)° and v = 665.0(9)å3. amazonite microcline, locally intergrown with albite, displays the following unit cell characteristics a= 8.584(4) å, b = 12.980 (6) å, c = 7.219(3) å, α = 90.79(6)°, β = 115.96(3)°, γ = 87.60(4)° and v = 721.5(4) å3. the chemical composition and structural formulae of feldspar from the second intermediate zone are reported in table 4. the formulae were calculated on the basis of eight oxygen atoms per formula unit. the feldspars from the čanište pegmatite are very homogeneous. the plagioclase composition averages about ab98an1or1 with a total range of variation less than 1 mole% ab. the alkali feldspar has compositions of ab6or94an0 with variation of less than 2 mole% ab. figure 4: photomicrographs of representative primary fluid inclusions from different sub-units of the čanište epidote-bearing pegmatite: a) hydrosaline (l+v+s) inclusion recorded within microcline from the wall zone; b) two-phase (l+v) inclusion hosted by microcline from the wall zone; c) two-phase inclusion (l+v) within epidote from the first intermediate zone; d) threephase inclusion (l+v+s) contains accidentally trapped anisotropic solid phase, epidote from the first intermediate zone; e) inclusion with accidentally trapped crystal, quartz from the second intermediate zone; f ) two-phase (l+v) inclusions from the quartz core. strmić palinkaš et al.: the evolution of the čanište epidote-bearing pegmatite, fyro macedonia: evidence from mineralogical and geochemical features geologia croatica 429 the criteria proposed by roedder (1984). primary fluid inclusions are sub-rounded to irregular in shape and up to 10 mm in size. usually these inclusions occur in individual clusters or in isolation. based on the number of phases, the primary microcline-hosted fluid inclusions could be subdivided into two additional sets: 1) polyphase (l+v+s) and 2) twophase (l+v) inclusions. polyphase inclusions comprise up to 50 vol. % of solid phases, highly saline aqueous solution and vapour bubbles (fig. 4a). solid phases are usually transparent and inactive in raman spectra. salt melting temperatures from 450 °c up to 600 °c (the limit of the heating-freezing stage) suggest salinity higher than 53.3 wt. % nacl equ. (bodnar & vityk, 1994). according to raman microspectroscopy data the vapour bubbles contain only water vapour. total homogenization occurs by the vapour phase disappearance at temperatures higher than 480 °c. the part of fluid inclusions did not homogenize below the upper temperature limit of the heating stage (600 °c), and consequently the bulk fluid properties and isochores can be calculated only for those inclusions with total homogenization below 600 °c (fig. 6). two phase inclusions contain liquid and vapour phases at room temperature (fig. 4b). degree of fill (f) varies between 0.75 and 0.80. eutectic temperature (te) around –52 the partitioning of the albite component between coexisting microcline and plagioclase solid-solutions can be employed as a pressure-dependent geothermometer (whitney & stromer, 1977). whereas temperature estimated from the two-feldspar geothermometer increases with pressure by l8 °c per kilobar (stromer & whitney, 1985), the formation temperature can be determined through a combination of the two-feldspar geothermometer with the fluid inclusion data (fig. 6). 3.2. fluid inclusion studies fluid inclusions from the wall zone amazonite microcline were classified as either primary or secondary according to table 4: representative microprobe analyses and calculated formulas for feldspars from the second intermediate zone of the čanište epidote-bearing pegmatite. albite amazonite microcline pt 1 pt 2 pt 3 pt 4 pt 5 pt 6 pt 7 pt 8 pt 9 chemical composition (wt. %) na2o 11.36 11.28 11.17 11.39 11.52 11.65 0.66 0.84 0.42 k2o 0.07 0.08 0.12 0.12 0.07 0.13 15.62 15.25 15.79 rb2o < d.l. < d.l. < d.l. < d.l. < d.l. < d.l. 0.22 0.25 0.11 cs2o < d.l. < d.l. < d.l. < d.l. < d.l. < d.l. 0.07 0.06 < d.l. cao 0.31 0.29 0.72 0.21 0.15 0.14 < d.l. < d.l. < d.l. bao < d.l. < d.l. < d.l. < d.l. < d.l. < d.l. < d.l. < d.l. 0.57 pbo < d.l. < d.l. < d.l. < d.l. < d.l. < d.l. 0.34 0.41 0.14 al2o3 20.08 19.93 20.52 19.63 19.81 19.68 18.25 18.38 18.61 fe2o3 < d.l. < d.l. 0.06 0.06 0.06 0.06 < d.l. < d.l. < d.l. sio2 68.91 68.87 68.12 69.31 69.52 69.23 65.24 64.54 64.47 tot 100.73 100.45 100.71 100.72 101.13 100.89 100.40 99.73 100.11 structural formula (atom. %) na+ 0.954 0.949 0.940 0.956 0.963 0.978 0.059 0.075 0.038 k+ 0.004 0.005 0.007 0.007 0.004 0.007 0.919 0.903 0.934 rb+ 0.000 0.000 0.000 0.000 0.000 0.000 0.007 0.007 0.003 cs+ 0.000 0.000 0.000 0.000 0.000 0.000 0.001 0.001 0.000 ca2+ 0.015 0.013 0.034 0.010 0.007 0.006 0.000 0.000 0.000 ba2+ 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.010 pb2+ 0.000 0.000 0.000 0.000 0.000 0.000 0.004 0.005 0.002 al3+ 1.025 1.020 1.050 1.002 1.007 1.004 0.992 1.006 1.016 fe3+ 0.000 0.000 0.002 0.002 0.002 0.002 0.000 0.000 0.000 si4+ 2.985 2.990 2.958 3.001 2.998 2.996 3.008 2.996 2.988 cats 4.982 4.977 4.990 4.978 4.981 4.993 4.989 4.994 4.991 o 8 8 8 8 8 8 8 8 8 < d.l. – below detection limit sr, mn and p are below detection limits. figure 5: microthermometric data for fluid inclusions from different subunits of the čanište epidote-bearing pegmatite; a) plots of ice-melting (tm ice) and clathrate-melting (tm clat) temperatures; b) plots of homogenization temperatures. geologia croatica 65/3geologia croatica 430 figure 6: pressure–temperature diagram summarizing the relevant information relating to the p–t history of the čanište epidote-bearing pegmatite. °c suggests cacl2 and nacl as the dominant dissolved salts (crawford, 1981). the final ice melting temperature (tm ice) has been measured between –7.5 and –8.5 °c (fig. 5a). the final ice melting temperatures and experimental data published by bodnar (1993) for the system h2o–nacl, indicate salinity ranges from 11.1 to 12.3 wt.% nacl equ. total homogenization (th) occurs between 440 and 460 °c by vapour-bubble disappearance (fig. 5b). bulk fluid density, utilizing the equation of state proposed by archer (1992) through the bulk software (bakker, 2003), spans from 0.809 to 0.863 g/cm3. the isochores were calculated with the isoc software (bakker, 2003) utilizing the equations of bowers & helgeson (1983) and bakker (1999) (fig. 6). the secondary inclusions in the wall zone amazonite microcline lie along curved trails, display irregular shape and comprise two phases (l+v). their size below 5 mm precludes microthermometric measurements. epidote is the only mineral from the first intermediate zone that hosts fluid inclusions large enough for microthermometric measurements. primary fluid inclusions occur either isolated or as clusters. they are two-phase (liquid + vapour) up to 15 mm in size, with an elongated, rounded or irregular shape (fig. 4c). some inclusions enclose birefringent insoluble solids (fig. 4d). the solids might be crystals trapped accidentally during the formation of fluid inclusions, rather than daughter minerals, judging by their inconsistent phase ratios. the vapour phase occupies around 20% of the total volume. raman microspectroscopy only revealed the presence of water. initial melting temperature between –42 and –62 °c suggests the presence of divalent cations, most likely ca, fe and mg (barker, 1995). the final ice melting temperature spanning from –5.6 to –6.7 °c (fig. 5a) indicates moderately saline fluids (8.7 and 10.1 wt.% nacl equ.). homogenization to a liquid phase occurs at temperatures between 180 and 210 °c (fig. 5b). the calculated fluid density ranges from 0.925 to 0.961 g/cm3. the bulk leachate data of fluid inclusions in epidote suggest cl– as major anion and na+ and mg2+ as the dominant cations (table 5). secondary inclusions, distributed along healed fractures of random orientation, were too small for microthermometric measurements (less than 5 mm). fluid inclusions were examined in quartz and albite from the second intermediate zone. the majority of the inclusions have a size below 10 mm. primary inclusions occur as single, isolated inclusions, or as randomly oriented groups, and commonly mark zones of host crystal growth. these inclusions exhibit irregular to rounded shapes and contain liquid and vapour phases with consistent volumetric proportions (f ≈ 0.80). frequently, inclusions comprise an insoluble solid phase, interpreted as accidentally trapped crystals (fig. 4e). raman microspectroscopy recorded only the presence of water, as for the samples from the first intermediate zone. eutectic temperatures around –52 °c indicate a ca-nacl system (shepherd et al., 1985). the temperatures of final ice melting ranging from –3.4 to –4.2 °c (fig. 5a) corresponding to salinity between 5.6 and 6.7 wt.% nacl equ. temperatures of homogenization into a liquid phase were recorded within an interval between 165 and 180 °c (fig. strmić palinkaš et al.: the evolution of the čanište epidote-bearing pegmatite, fyro macedonia: evidence from mineralogical and geochemical features geologia croatica 431 5b). bulk fluid density, estimated from fluid inclusion data, spans from 0.931 to 0.951 g/cm3. constructed isochores are shown in figure 6. the intersection of isochores with the two-feldspar geothermometer published by whitney & stromer (1977), and corrected for pressure according to the procedure described by stromer & whitney (1985), revealed the formation temperature of the second intermediate zone in the range between 445 and 465 °c under pressure between 4.8 and 5.6 kbar. fluid inclusions from the monomineralic massive quartz core show irregular to rounded shapes and range in size up to 15 mm (fig. 4f). they occur either isolated or in clusters of 5 to 10 inclusions arranged in three-dimensional, nonplanar arrays. inclusions comprise two phases (liquid and vapour) and have uniform degree of fill around 0.8. microraman spectroscopy measurements recognized the presence of co2 within the vapour phase. due to poor optical quality, an initial melting temperature (eutectic temperature, te) was not detected. the formation of the co2 clathrate phase additionally hampers interpretation of low temperature microthermometric data. cla th rate melting temperature (tm clat) in the interval between +8.1 and +8.9 °c (fig. 5a) corresponds to a salinity of 2.2 to 3.8 wt.% equ. nacl. homogenization of the carbonic phase proceeds into vapour phase around 28 °c. total homogenization by vapour-bubble disappearance occurs in a temperature range between 155 and 170 °c (fig. 5b). bulk fluid density, calculated by the bulk software (bakker, 2003), ranges between 0.882 and 0.892 g/cm3. the leachate data revealed the predominance of na+, k+ and cl– in the aqueous fluids responsible for the massive quartz core crystallization (table 5). 4. discussion magmatic differentiation by crystal fractionation generally results in the transition of low-volatile content silicate melt (producing normal igneous rocks), through hydrous silicate melt (producing pegmatites), to late-stage water-rich fluids (producing metal ore deposits) (roedder, 1992). the majority of fluid inclusion studies performed on pegmatites suggest crystallization from a water-saturated system and, consequently, immiscibility between the melt phase and volatile fluid (e.g. beurlen et al., 2001; thomas et al., 2011; thomas & davidson, 2012). the crystallization evolution of the čanište epidotebearing pegmatite, is reconstructed using thermodynamic mineral equilibria and fluid inclusion data. the pegmatite originates from intrusion of granodioritic melt into the pelagonian crystalline basement in the upper carboniferous (most, 2003). the melt that ultimately produced the čanište pegmatite was relatively fe-rich in its initial stage, as indicated by the crystallization of epidote, haematite and almandine. the complete absence of fluxes (b, p, f), and relatively high concentrations of compatible elements (e.g., ca, fe, zr) are very different in comparison to common granitic systems, although similar chemistry has been related with leucotonalitic to quartz leucogabbroic pegmatites (novák & gadas, 2010). the čanište pegmatite exhibits a zoned internal structure with four distinctive zones: the wall zone, two intermediate zones and the quartz core. textural characteristics suggest primary crystallization from melt in order; wall zone → first intermediate zone → second intermediate zone → core. the progressive crystallization resulted in melt composition changes. concentrations of ca, fe and k decreased, and concentrations of na and si increased. fluid inclusion data suggest subsequent crystallization under a steady decrease of temperature and isobaric conditions. furthermore, fluid inclusion study indicates that aqueous fluids played an important role in the genesis of the čanište pegmatite. the co2 content increased with progressive fractional crystallization, and a significant amount of co2 is present only in the very late stage of crystallization. the presence of primary highly saline aqueous inclusions in the wall zone microcline supports the magmatic origin of the entrapped fluid (e.g. roedder, 1992). coexisting polyphase (l+v+s) and two-phase (l+v) inclusions as well as large variation in salinity suggest the accidental entrapment near the l/l+s interface of the p-t-x space (e.g. bakker & elburg, 2006). whereas the trapping conditions might be estimated from the intersection of isochores constructed for two sets of simultaneously trapped fluid inclusions, and assuming that two principal sets of primary inclusions are contemporaneous, only the minimum possible formation temperature and pressure (600 °c, 3.8 kbar; fig. 6) can be defined due to lack of homogenization temperatures for high temperature polyphase inclusions. the absence of aplites indicates a nearly constant pressure during pegmatite crystallization (e.g. nabelek et al., 2010). assuming a pressure of between 4.8 and 5.6 kbar, (estimated for the second intermediate zone by the combination of two-feldspar geothermometer and fluid inclusion data), the formation temperature of the wall zone then ranges from ca. 650 to 760 °c (fig. 6). the formation temperature of the first intermediate zone in the interval between 445 and 550 °c is constrained from the microthermometric data obtained on epidote, assuming table 5: the bulk leachate analyses for epidote and quartz from the čanište epidote-bearing pegmatite. li+ na+ k+ mg2+ ca2+ fclbrino3 so4 2ana+/ak+ ana+ 2/aca2+ sample sub-unit mmol/l epidote the 1st intermediate zone 3.50 75.9 40.0 61.5 0.02 14.1 148.7 0.2 0.00 2.1 2.0 2 230787 quartz the quartz core 0.70 32.4 12.0 0.0 5.68 12.2 22.2 0.0 0.01 4.0 2.2 3 185 geologia croatica 65/3geologia croatica 432 figure 7: log fo –temperature diagram at 5.5 kbar pressure and ah2o = 1 for the system ca–k-fe–al-si–o–h showing proposed environments for formation of the first intermediate zone mineral assemblage (hem + ms + otz + alm + mic). mineral stability fields based on the equation: 2 fe3al2(sio4)3 + 2 kalsi3o8 + 2 h2o +3/2 o2 ↔ 3 fe2o3 + 2 kal2alai3o10(oh)2 + 6 sio2 (almandine) (microcline) (haematite) (muscovite) (quartz) and thermodynamic data from kelley (1960), helgeson et al. (1978), wagman et al. (1982), shock & helgeson (1988) and anovitz et al. (1993). abbreviations: hem – haematite; ms – muscovite; qtz – quartz; alm – almandine; mic – microcline). nearly constant pressure during the pegmatite crystallization (4.8–5.6 kbar, fig. 6). the mineral assemblage comprising almandine, microcline, haematite, muscovite and quartz can be used as an indicator of oxygen fugacity. according to thermodynamic data published by kelley (1960), helgeson et al. (1978), wagman et al. (1982), shock & helgeson (1988) and anovitz et al. (1993) and the following equation: 2 fe3al2(sio4)3 + 2 kalsi3o8 + 2 h2o +3/2 o2 ↔ (almandine) (microcline) 3 fe2o3 + 2 kal2alai3o10(oh)2 + 6 sio2 (haematite) (muscovite) (quartz) oxygen fugacity during deposition of the first intermediate zone was between 10–22 and 10–19.5 bar (fig. 7). electron microprobe data were mostly used to calculate chemical formulas of selected minerals from the first intermediate zone. whereas the epidote group comprises a widespread and chemically complex family of silicates the composition of which can be represented as a2m3(t2o7)(to4) o(oh) (a = ca2+, mn2+, sr2+, ree3+; m = al3+, fe3+, fe2+, mn3+, mg2+; t = si4+, al3+), the major issue was to estimate definite mineral formula. according to the data listed in table 1, epidote from the čanište pegmatite belongs to the clinozoisite subgroup with the formula (ca1.96–1.99mn0.02– 0.03fe2+ 0.00–0.02)(al2.17–2.46fe3+ 0.51–0.82ti0.00–0.01)(si2o7) (si0.99–1.00al0.00–0.01o4)o(oh). the majority of analyzed points (pt1 – pt6) display ps value [ps = fe3+/(fe3++al)] in the range between 26 and 29 supporting the magmatic origin of epidote (tulloch, 1986; schmidt & poli, 2004). the presence and relative proportions of various garnet endmembers can give insights into conditions of formation. the garnet from the čanište pegmatite is predominantly grossular with subordinate almandine and spessartine components, minor andradite and a negligible pyrope content. almandinebearing mineral paragenesis generally points to the weakly evolved granitic/granodioritic rocks generated at great depths (e.g. green, 1977; whitworth, 1992). zircon from the čanište epidote-bearing pegmatite has a nearly stoichiometric composition with a zr/hf atomic ratio between 39 and 41. the content of u, th and ree, unusually low for the pegmatitic mineral assemblage, is indicative of the weakly differentiated pegmatitic system. crystallization of minerals from the wall and the first intermediate zone decreased activities of calcium, potassium and iron. consequently, the residual melt has been enriched in water, silica and sodium. increased sodium activity induced crystallization of the second intermediate zone mineral assemblage with albite and quartz as the major constituents. microcline occurs sporadically. as already mentioned, microthermometric measurements connected with the two-feldspar geothermometer, constrain the second intermediate zone crystallization conditions at temperatures between 445 and 465 °c under pressure between 4.8 and 5.6 kbar (fig. 6). the very last stage in the čanište pegmatite genesis is represented by the crystallization of the massive quartz core. according to fluid inclusion data, the massive quartz core was produced under the influence of low-saline and co2 enriched fluid at a temperature between 400 and 480 °c, assuming the formation pressure between 4.8 and 5.6 kbar (fig. 6). 5. conclusion textural features and fluid inclusion data suggest that the čanište epidote-bearing pegmatite formed as a result of subsequent and successive crystallization from a granodioritic melt. mineral assemblages, especially the presence of almandine and u, th, ree-depleted zircon, suggests a weakly differentiated pegmatitic system. the course of pegmatite crystallization was proceeding close to isobaric conditions. the formation pressure is estimated within the range of between 4.8 and 5.6 kbar (average at 5.2 kbar). the primary wall zone mineral assemblage (microcline ± biotite, quartz) crystallized from the melt between 650 to 760 °c. cooling of the melt below 550 °c at oxygen fugacity between 10–22 and 10–19.5 bar, caused deposition of the first intermediate zone (epidote + haematite + grossular + muscovite + quartz + almandine ± zircon, beryl, microcline, quartz). progress of crystallization decreased activities of calcium, iron and potassium, and increased water, silica and sodium contents in the residual melt. the second intermediate zone comprises albite, which crystallized from the strmić palinkaš et al.: the evolution of the čanište epidote-bearing pegmatite, fyro macedonia: evidence from mineralogical and geochemical features geologia croatica 433 na-enriched melt. the formation temperature estimated from the fluid inclusion data, as well as from two-feldspar geothermometer, spans the range from 445 to 465 °c. the massive quartz core was produced at temperatures between 400 and 480 °c from the very last melt residue enriched in silica, water and co2 content. acknowledgment we are grateful to reviewers, pavel uher and sibila borojević šoštarić, whose comments significantly improved the paper. this study was supported by the croatian ministry of sciences, technology and sports (projects no. 119-0982709-1175 and no. 119-0000000-1158). references anovitz, l.m., essene, e.j., metz, g.w., bohlen, s.r., westrum, e.f. jr. & hemingway, b.s. (1993): heat capacity and phase equilibria of almandine, fe3al2si3o12.– geochim. cosmochim. acta, 57, 4191–4204. doi: 10.1016/0016-7037(93)90315-n archer, d.g. (1992): thermodynamic properties of the nacl+h2o system. ii. thermodynamic properites of nacl (aq), nacl•2h2o(cr) and phase equilibria.– j. phys. chem. ref. data, 21, 793–829. doi:10.1063/1.555915 armbruster, t., bonazzi, p., akasaka, m., bermanec, v., chopin, c., gieré, r., heuss-assbichler, s., liebscher, a., menchetti, s., pan, y. & pasero, m. (2006): recommended nomenclature of epidote-group minerals.– eur. j. mineral., 18, 551–567. doi: 10.1127/0935-1221/2006/0018-0551 bakker, r.j. (1999): adaption of bowers & helgeson (1983) equation of state to isochore and fugacity coefficient calculation in the h2o-co2-ch4-n2-nacl fluid system.– chem. geol., 154, 225–236. doi: 10.1016/s0009-2541(98)00133-8 bakker, r.j. (2003): package fluids 1. computer programs for analysis of fluid inclusion data and for modelling bulk fluid properties.– chem. geol., 194, 3–23. doi: 10.1016/s0009-2541(02)00268-1 barker, a.j. (1995): post-entrapment modification of fluid inclusions due to overpressure: evidence from natural samples.– j. metamorph. geol., 13, 737–750. doi: 10.1111/j.1525-1314.1995.tb00256.x bermanec, v., tibljaš, d., gessner, m. & kniewald, g. (1988): monazite in hydrothermal veins from alinci, yugoslavia.– mineral. petrol., 38, 139–150. doi: 10.1007/bf01164318 bermanec, v., tibljaš, d. & kniewald, g. (1992): uraniumrich metamict senaite from alinci, macedonia, yugoslavia.– eur. j. mineral., 4, 331–335. bermanec, v., palinkaš, l.a. & strmić, s. (2001): mineralogy of pegmatite with giant epidote crystals, near čaniste, macedonia.– in: piestrzynski, a. (ed.): mineral deposits at the beginning of the 21st century, proceed. 6th biennial sga meeting, 939–942. beurlen, h., da silva, m.r.r., de castro, c. (2001): fluid inclusion microthermometry in be–ta–(li–sn)-bearing pegmatites from the borborema province, northeast brazil.– chem. geol., 173, 107–123. doi: 10.1016/s0009-2541(00)00270-9 bodnar, r.j. (1993): revised equation and table for determining the freezing point depression of h2o-nacl solutions.– geochim. cosmochim. acta, 57, 683–684. doi: 10.1016/0016-7037(93)90378-a bodnar, r.j. & vityk m.o. (1994): interpretation of microthermometric data for h2o-nacl fluid inclusions. in: de vivo, b. & frezzotti m.l. (eds.): fluid inclusions in minerals, methods and applications, virginia tech, blacksburg, va, 117–130. bonazzi, p. & menchetti, s. (1995): monoclinic members of the epidote group: effects of the al, fe3+, fe2+ substitution and of the entry of ree3+.– mineral. petrol., 53, 133–153. doi: 10.1007/ bf01171952 bottrell, s.h., yardley, b.w.d. & buckley, f. (1988): a modified crush-leach method for analysis of fluid inclusion electrolytes.– bull. mineral., 111, 279–290. bowers, t.s. & helgeson, h.c. (1983): calculation of the thermodynamic and geochemical consequences of nonideal mixing in the system h2o–co2–nacl on phase relations in geological systems: equation of state for h2o–co2–nacl fluids at high pressures and temperatures.– geochim. cosmochim. acta, 47, 1247–1275. doi: 10.1016/0016-7037(83)90066-2 bumham, c.w. & nekvasil, h. (1986): equilibrium properties of granite pegmatite magmas.– am. min., 71, 239–263. can, i. (2002): a new improved na/k geothermometer by artificial neural networks.– geothermics, 31, 751–760. doi: 10.1016/s03756505(02)00044-5 cota, a.c., wise, m.a. & owens, b.e. (2010): textural and chemical constraints on the origin of epidote in granitic pegmatites.– geol. soc. am., abstracts with progr., 42, p. 159. crawford, m.l. (1981): phase equilibria in aqueous fluid inclusions.– mineral. assoc. can., short course, 6, 75–100. dumurdzanov, n. (1985): petrogenetic characteristics of the high metamorphic and magmatic rocks of the central and western part of the selečka mts. (pelagonian massif), sr macedonia, yugoslavia.– geol. maced., 2, 173–220. franz, g. & smelik, e.a. (1995): zoisite–clinozoisite bearing pegmatites and their importance for decompressional melting in eclogites.– eur. j. mineral., 7, 1421–1436. fuertes-fuente, m., agustin, m.-i., boiron, m.c. & vinuela, j.m. (2000): p-t path and fluid evolution in the franqueira granitic pegmatite, central galicia, northwestern spain.– can. min., 38, 1163–1175. doi: 10.2113/gscanmin.38.5.1163 helgeson, h.c., delany, j.m., nesbitt, h.w. & bird, d.k. (1978): summary and critique of the thermodynamic properties of rock-forming minerals.– am. j. sci., 278-a, 1–229. holland, t.j.b. & redfern, s.a.t. (1997): unit cell refinement from powder diffraction data: the use of regression diagnostics.– mineral. mag., 61, 65–77. icdd powder diffraction file 2 (2004): database sets 1–54. international centre for diffraction data (icdd), newton square, pennsylvania, usa. ivanov, t., bogoevski, k., radović, n. & ivanova, v. (1966): guidebook for fieldtrips in sr macedonia, yugoslavia.– 6th meeting of geologists of yugoslavia, ohrid, 17 p. jahns, r.h. & burnham, c.w. (1969): experimental studies of pegmatite genesis: i. a model for the derivation and crystallization of granitic pegmatites.– econ. geol., 64, 843–864. doi: 10.2113/ gsecongeo.64.8.843 janeczek, j. (2007): intragranitic pegmatites of the strzegom-sobótka massif – an overview.– in: kozowski, a. & wiszniewska, j. (eds.): granitoids in poland. arch. miner. monogr., 1, 193–201. jovanovski, g., boev, b., makreski, p., najdoski, m. & mladenovski, g. (2003): minerals from macedonia. xi. silicate varieties and their localities – identification by ft ir spectroscopy.– bull. chem. technol. macedonia, 22, 111–141. kelley, k.k. (1960): contributions to the data in theoretical metallurgy xiii: high temperature heat content, heat capacities and entropy data for the elements and inorganic compounds.– u. s. bureau of mines bulletin, 584, 1–232. geologia croatica 65/3geologia croatica 434 liebscher, a., franz, g., frei, d. & dulski, p. (2007): highpressure melting of eclogite and the p–t–x history of tonalitic to trondhjemitic zoisite-pegmatites, münchberg massif, germany.– j. petrology, 48, 1001–1019. doi: 10.1093/petrology/egm008 locock, a.j. (2008): an excel spreadsheet to recast analyses of garnet into end-member components, and a synopsis of the crystal chemistry of natural silicate garnets.– comput. & geosci., 34, 1769–1780. doi: 10.1016/j.cageo.2007.12.013 london, d. (1986): magmatic-hydrothermal transition in the tanco rare-element pegmatite; evidence from fluid inclusions and phaseequilibrium experiments.– am. min., 71, 76–395. london, d. (1990): internal differentiation of rare-element pegmatites: a synthesis of recent research.– geol.soc. am., spec.pap., 246, 35–50. london, d., morgan, g.b. & hervig, r.l. (1989): vapor-undersaturated experiments in the system macusanite-h2o at 200 mpa, and the internal differentiation of granitic pegmatites.– contrib. mineral. petrol., 102, 1–17. doi: 10.1007/bf01160186 most, t. (2003): geodynamic evolution of the eastern pelagonian zone in northwestern greece and the republic of macedonia.– unpubl. phd thesis, university of tuebingen, tuebingen, 195 p. nabelek, p.i., whittington, a.g. & sirbescu, m.-l.c (2010): the role of h2o in rapid emplacement and crystallization of granite pegmatites: resolving the paradox of large crystals in highly undercooled melts.– contrib. mineral. petrol., 160, 313–325. doi: 10.1007/s00410-009-0479-1 novak, m. & gadas, p. (2010): zoned, anorthiteand grossularitebearing, leucotonalitic pegmatite from serpentinized lherzolite at ruda nad moravou, staré město unit, czech republic.– can. min., 48, 629–650. doi: 10.3749/canmin.48.3.629 panalytical (2004): x'pert highscore plus version 2.1. panalytical, almelo, netherlands. radusinović, d. & markov c. (1971): macedonite lead titanate: a new mineral.– am. min., 56, 387–394. roedder, e. (1992): fluid inclusion evidence for immiscibility in magmatic differentiation.– geochim. cosmochim. acta, 56, 5–20. doi: 10.1016/0016-7037(92)90113-w schmidt, m.w. & poli, s. (2004): magmatic epidote.– rev. min. geochem., 56, 399–430. doi: 10.2138/gsrmg.56.1.399 shepherd, t.j., rankin, a.h. & alderton, d.h.m. (1985): a practical guide to fluid inclusion studies. blackie, glasgow, 239 p. shock, e.l. & helgeson, h.c. (1988): calculation of the thermodynamic and transport properties of aqueous species at high pressures and temperatures: correlation algorithms for ionic species and equation of state predictions to 5 kb and 1000°c.– geochim. cosmochim. acta, 52, 2009–2036. doi: 10.1016/0016-7037(88)90181-0 sirbescu, m.-l.c., hartwick, e.e. & student, j.j. (2008): rapid crystallization of the animikie red ace pegmatite, florence county, northeastern wisconsin: inclusion microthermometry and conductive-cooling modelling.– contrib. mineral. petrol., 156, 289–305. doi: 10.1007/s00410-008-0286-0 swanson, s.e. & veal, w.b. (2010): mineralogy and petrogenesis of pegmatites in the spruce pine district, north carolina, usa.– j. geosciences, 55, 27–42. doi: 10.3190/jgeosci.062 thomas, a.v. & spooner e.t.c. (1988): fluid inclusions in the system h2o-ch4-nacl-co2 from metasomatic tourmaline within the border unit of the tanco zoned granitic pegmatite, s.e. manitoba.– geochim. cosmochim. acta, 52, 1065–1075. doi: 10.1016/0016-7037(88)90261-x thomas, a.v. & spooner e.t.c. (1992): the volatile geochemistry of magmatic h2o-co2 fluid inclusions from the tanco zoned granitic pegmatite, southeastern manitoba, canada.– geochim. cosmochim. acta, 56, 49–65. doi: 10.1016/0016-7037(92)90116-z thomas, r., davidson p., beurlen, h. (2011): tantalite-(mn) from the borborema pegmatite province, northeastern brazil: conditions of formation and meltand fluid-inclusion constraints on experimental studies.– miner. deposita, 46, 749–759. doi: 10.1007/ s00126-011-0344-9 thomas, r. & davidson p. (2012): water in granite and pegmatiteforming melts.– ore geol. rev., 46, 32–46. doi: 10.1016/j.oregeorev.2012.02.006 tulloch, a.j. (1986): comment on “implications of magmatic epidote-bearing plutons on crustal evolution in the accreted terranes of northwestern north america” and “magmatic epidote and its petrologic significance”.– geology, 14, 187–188. doi: 10.1130/0091-7613 (1986)14<186:caroio>2.0.co;2 wagman, d. d., evans, w.h., parker, v.b., schumm, r.h. & halow, i. (1982): the nbs tables of chemical thermodynamic properties. selected values for inorganic and c1 and c2 organic substances in si units.– j. phys. chem. ref. data 11, sup. 2, 1–392. doi: 10.1063/1.555845 zebec, v. & radanović-gužvica, b. (1992): crystallographic determination of titanite from smilevski dol in selečka mountain, macedonia.– geol. croat., 45, 63–68. manuscript received april 30, 2012 revised manuscript accepted august 12, 2012 available online october 30, 2012 schlagintweit.indd 185 � ab stra ct the present paper compiles an up-to-date taxonomic inventory of dasycladalean green algae of the kimmeridgianearly berriasian plassen carbonate platform and their resediments in basinal sediments (e.g., barmstein limestone, sillenkopf formation) of the northern calcareous alps of austria (p.p. germany). today, the plassen carbonate platform sensu lato (or plassen group) is divided into three independent carbonate platforms with radiolarite deepwater basins between: the wolfgangsee carbonate platform to the north, the plassen carbonate platform sensu stricto in a central position and the lärchberg carbonate platform to the south. all together 42 taxa are reported from these platforms and associated resediments, each shortly commented and illustrated. amongst these, there are taxa common in all three platforms, others exhibit restricted distributions. these peculiarities can be explained by the different lithostratigraphic and overall geodynamic evolution of the three platforms. in many cases, it allows the assignment of resediments in basinal series to a certain platform as a helpful palaeobiogeographical tool when other data are lacking. keywords: dasycladales, taxonomy, palaeogeography, northern calcareous alps, austria the dasycladalean algae of the plassen carbonate platform (kimmeridgianearly berriasian): taxonomic inventory and palaeogeographical implications within the platform-basin-system of the northern calcareous alps (austria, p.p. germany) � felix schlagintweit lerchenauerstr. 167, d-80935 münchen, german; (ef.schlagintweit@t-online.de) doi:104154/gc.2011.16 geologia croatica 64/3 185–206 4 figs. 1 tab. 5 pls. zagreb 2011 geologia croaticageologia croatica 1. introduction the ocurrence of upper jurassic shallow-water limestones in the northern calcareous alps is known since the midth of the 19th century (e.g., von hauer, 1857; geyer, 1884; mojsisovics, 1868). in contrast to the huge late triassic hauptdolomit/dachstein carbonate platform, these late jurassic shallow-water carbonates should only form isolated reefs. in early to middle jurassic times, the deposition was characterized by deep-water carbonates and/or cherty sediments. after tectonic movements in the early late jurassic, these shallow-water carbonates were described as resting transgressively above uplifted blocks of triassic rocks (trauth, 1950; plöchinger, 1964; tollmann, 1965, 1981, 1985; mandl, 1982; steiger & wurm, 1980). in contrast, recent results showed that this shallow-water evolution was installed in the areas of uplifting rises (e.g., trattberg rise, brunnwinkl rise, gawlick et al., 2007) geologia croatica 64/3geologia croatica 186 around the oxfordian-kimmeridgian boundary. due to later erosion, these contacts are not more preserved and can only be reconstructed by analysis of mass-fl ow deposits in the adjacent basinal areas. all preserved shallow-water carbonate successions evolved in a shallowing upward manner abo ve basinal deposits. from the topographic rises, representing nappe fronts (gawlick et al., 1999), the platforms prograded onto adjacent basin sequences delivering sediments to the deeper water areas (frisch & gawlick, 2003; gawlick & frisch, 2003). results obtained from investigations of the last decade have shown that these today isolated occurrences belonged to at least three different shallow water areas today united as the plassen carbonate platform (= plassen group in gawlick et al., 2009): the wolfgangsee carbonate platform to the north, the central platform or plassen carbonate platform sensu stricto (in part the former plassen limestone or plassen formation) and the lärchberg carbonate platform to the south (fig. 1). the exact palaeogeographic position of the different platform occurrences in the northern calcareous alps can often not easily be reconstructed. due to multiphase tectonic movements, many of these occurrences were sheared off from their basements and occur in an allochthonous position. therefore, it is very often not easy to decide to which platform these occurrences belong especially when the normal underlying sequences are missing. for an exact reconstruction of the jurassic palaeogeography and the tectonic motions, however, a detailed knowledge of the derivation of the shallow-water occurrences is essential. beside some special sedimentological and microfacies features distinguishing the different platforms (gawlick et al. 2009, for details), also the microfaunistic and -fl oristic content in the different platforms can help for better palaeogeographic reconstructions. dasycladales are widespread constituents of the plassen carbonate platform (e.g., flügel, 1964; fenninger & hötzl, 1967; steiger & wurm, 1980; darga & schlagintweit, 1991; dya, 1992; schlagintweit & ebli, 1999; rasser & fenninger, 2002; schlagintweit et al., 2005) but also occur within the resediments of the barmstein limestone (fenninger, 1972; steiger, 1981; gawlick et al., 2005, 2010; schlagintweit & gawlick, 2007) or the sillenkopf formation (missoni figure 1: a) tectonic map of the middle part of the northern calcareous alps show ing recent block confi guration with occurrences of the wolfgangsee carbonate platform (pink), oberalm for mation + barmstein limestone (blue), central plassen carbonate platform (yellow), sillenkopf formation (green) lärch berg carbonate plat form (red) (after frisch & gawlick, 2003, slightly modifi ed). wfz = wolfgangsee fault zone. the two white arrows show the small out crops of the sillenkopf formation. b) platform-basin confi guration during the late tithonian (based on gawlick et. al., 2009). colo urs refer to a. felix schlagintweit: the dasycladalean algae of the plassen carbonate platform (kimmeridgian-early berriasian)... geologia croatica 187 et al., 2001). based on thin-section analyses of several thousand samples coming from various different localities of all three platforms and their resediments, an up-to-date inventory of the dasycladalean algae is presented and analyzed with respect to their occurrence/absence in different parts of the late jurassic to earliest cretaceous platform-basin-system of the northern calcareous alps. each taxon is illustrated and shortly commented. the distribution of the dasycladale fl ora is viewed and interpreted with respect to differences in the lithostratigraphic evolution of the platforms and their geodynamic framework. 2. data analysis the algal inventory of the plassen carbonate platform and their resediments consists of 24 genera; 3 taxonomically insuffi ciently known taxa are treated as gen. et sp. indet. (tab. 1). one taxon, salpingoporella pygmaea (gümbel) is reported from all three platforms and the associated resediments. the number of taxa of the plassen carbonate platform s. str. with 22 (+ 4 uncertain records) equals more or less the number known from the lärchberg carbonate platform with 26. the number of known taxa of the wolfgangsee carbonate platform with 9 is distinctly reduced in comparison to both the plassen carbonate platform s. str. and the lärchberg carbonate platform. concerning the resediments of these shallow-water carbonates within basinal sediments, the inventory of taxa from the barmstein limestone with 27 is distinctly the highest, followed by the sillenkopf formation with 6 and the rofan breccia with 1 (3?) taxa. there are taxa that are restricted to the wolfgangsee carbonate platform (1 taxon), the barmstein limestone (5,?7 taxa), the plassen carbonate platform s. str. (1 taxon) and the most significantly to the lärchberg carbonate platform (10 taxa). these differences and peculiarities are discussed later in the paper when each unit is dealed with separately. the most frequent genus is clypeina michelin with 7 species followed by salpingoporella pia with 4 species. there are 7 species that can occur in great abundances in often more or less monospecifi c assemblages: clypeina juras sica favre, neoteutloporella socialis (praturlon), campbelliella striata (carozzi), neoteutloporella obsoleta (carozzi), gen. et sp. indet. 2, occasionally also rajkaella bartheli (bernier) and salpingoporella annulata carozzi. from the 42 reported taxa, only 4 (~ 10 %) are reported from all the three platforms and the resediments of the barmstein limestone and the sillenkopf formation. three taxa are reported from all three platforms and the barmstein limestone, but lacking in the sillenkopf formation. in comparisons to other regions of the alpine-mediterranean realm, the dasycladalean fl ora of the plassen carbonate platform of the northern calcareous alps can be considered a comparable rich association (see tab. 1 in rasser & fenninger, 2002). the main reason therefore is the great variety of different platform palaeoenvironments each with characteristic associations. furthermore, some typical environments, e.g., reefal and peri-reefal facies, occur twice (late kimmeridgian and latest tithonian-?earliest berriasian) (fig. 2). in this case we fi nd common taxa such as salpingoporella pygmaea in both reefal intervals and, due to differences in stratigraphic ranges, taxa that are either only occurring in the kimmeridgian or late tithonian (e.g., neoteutloporella socialis) reefal and peri-reefal carbonates. 2.1. wolfgangsee carbonate platform data from the wolfgangsee carbonate platform are available from mount falkenstein (kügler et al., 2003), mount drei brüder (gawlick et al., 2007) and mount bürgl (schlagintweit et al., 2008; gawlick & schlagintweit, 2010). all these occurrences start with resediments (breccias, mass-fl ows) above basinal series that can attain several tens of metres of thicknesses, followed by slope and reefal platform margin deposits. the rare debris of the dasycladale clypeina jurassica favre gives evidence of lagoonal infl uences that have so far not been detected in outcrops. the wolfgangsee carbonate platform was drowned in the late tithonian (intermedia subzone), witnessed by calpionellid table 1: distribution of kimmeridgian to early berriasian dasycladales of the northern calcareous alps within the plassen carbonate platform sensu lato: wolfgangsee carbonate platform (wcp), plassen carbonate platform sensu stricto (pcp), lärchberg carbonate platform (lcp) and the associated resediments, seekarspitz limestone (or rofan breccia) (sl), barmstein limestone (bl) and sillenkopf formation (sif). estimated abundances: * rare, ** common, *** abundant. 1) and 4) only locality mount jainzen; 2) only locality mount hornkogel and mount kehlstein; 3) only locality mount krahstein; 5) only locality mount falkenstein. geologia croatica 64/3geologia croatica 188 wackestones on the top of the series (gawlick & schlag intweit, 2010). the age of the basal resediments is unknown; the occurrence of the benthic foraminifera labyrinthina mirabilis weynschenk and kilianina? rahonensis foury & vincent, however, indicate a minimum age of kimmeridgian. therefore it is also unknown whether the reefal carbonates of the wolfgangsee carbonate platform can stratigraphically be correlated with the fi rst reefal interval of the plassen carbonate platform s. str. (~ late kimmeridgian) or are somehow younger (?latest kimmeridgian-early tithonian). in conclusion, more data are needed for a detailed lithostratigraphic analysis of the wolfgangsee carbonate platform. for illustrations of the microfacies types of the wolfgangsee carbonate platform see gawlick et al. (2007, 2009), and gawlick & schla gint weit (2010). within the three platforms, the wolfgangsee carbonate platform shows the lowest number of taxa with 9 species, some of these (clypeina loferensis, clypeina parasolkani, salpingoporella annulata) are only reported from mount jainzen. suppiluliumaella delphica (carras) seems to be restricted to the wolfgangsee carbonate platform. dissocladella? n. sp. was detected at mount jainzen in peri-reefal limestones, suppiluliumaella delphica (carras) within similar facies only from mount falkenstein (see also fenninger & holzer, 1972, pl. 17, fi g. 6, fi gured as macroporella gigantea carozzi). both taxa have so far not been reported for sure from any other locality within the northern calcareous alps. as time equivalent facies is reported from many other localities of the plassen carbonate platform, it is assumed that this has no special reason and future fi ndings of both taxa can be expected. the reduced number of taxa of the wolfgangsee carbonate platform as a whole can be explained by the stratigraphic restriction (kimmeridgian-early tithonian) with respect for example to the plassen carbonate platform s. str. on the one hand as the wolfgangsee carbonate platform was drowned in the late tithonian (gawlick & schlagintweit, 2010). on the other hand, only at a small part of mount jainzen, interpreted as being a part of the former wolfgangsee carbonate platform (see gawlick et al., 2007), carbonates refered to the closed lagoonal facies have been detected (unpubl. data). therefore, most taxa characteristic for the lagoonal facies are missing in the wolfgangsee carbonate platform. 2.2. seekarspitz limestone (or rofan breccia) following the current model of gawlick et al. (2010), the informal seekarspitz limestone (or rofan breccia), represents resediments of the wolfgangsee carbonate platform that were shed towards the north (fig. 1b). the name refers to mount rofanspitze in the sonnwend mountains of tyrol. it is worth to mention, that the two widespread late jurassic foraminifers protopeneroplis striata and labyrinthina mirabilis were described from this locality (weynschenk 1950, 1951). in general, little is known about the micropaleontology of the seekarspitz limestone. amongst the dasycladalean algae, only salpingoporella pygmaea (gümbel) is rather common. a possible fragment of suppiluliumaella delphica (carras) was observed in the obersee breccia in the ybbsitz area of lower austria, which, according to gawlick et al. (2009), could represent an equivalent to the rofan breccia. although more samples are needed to be studied, the number of dasycladalean algae will presumably not increase signifi cantly as the thin-sections studied show a rather uniform micropaleontological content. also, the algal content of the wolfgangsee carbonate platform as the assumed source area is rather low. 2.3. plassen carbonate platform s. str. one of the best studied occurrences and most complete successions of the plassen carbonate platform is the name giving type-locality mount plassen near hallstatt (schlagintweit et al. 2003, 2005). it represents the most complete sequence from the initial shallowing-upwards to the fi nal drowning phase. as it is the reference section for the plassen carbonate platform s. str. its facies evolution with respect to dasycladalean algal occurrences is shortly presented (fig. 2). in the initial phase of the plassen carbonate platform, coral patch-reefs following slope deposits were installed at the platform margin(s), that, together with the associated peri-reefal deposits contain a dasycladale assemblage of salpingoporella pygmaea (gümbel), petrascula bursiformis (ettalon), griphoporella jurassica (endo) and gyroporella? sp. the patch-reef facies can be ascribed to the late kimmeridgian (gawlick et al., 2004, e.g. locality krahstein). at the type-locality mount plassen, the platformmargin facies is partly replaced by labyrinthina shoals devoid of dasycladales and followed by transgressive-regressive cycles of tidal fl at and lagoonal deposits. the latter are typically dominated by an association of rivulariacean-type porostromate algae and an assemblage of dasycladales amongst salpingoporella annulata carozzi, clypeina jurassica favre, clypeina cf. parasolkani farinacci & radoičić or campbelliella striata (carozzi). approximately around the early-late tithonian boundary, these mainly sea-level controlled transgressive-regressive (t-r) cycles are followed by inner platform facies with typical lagoonal wackestones. especially in the transitional beds (between the t-r-cycles and the inner lagoon) the dasycladale campbelliella striata (carozzi) occurs in great abundances forming a monospecifi c assemblage (fig. 2). in the upper tithonian lagoonal wackestones dasycladales are widespread with typical taxa including clypeina cf. parasolkani farinacci & radoičić, otternstella lemmensis (ber nier), clypeina loferensis schlagintweit, dieni & radoičić, clypeina jurassica favre, gen. et sp. indet. 2 and rajkaella bartheli (bernier). the latter three can occur in more or less monospecifi c assemblages, e.g., clypeinaor rajkaella-wackestones. the lagoonal carbonates are followed by back-reef, reefal platform margin and fi nally slope deposits. the total stratigraphic interval of the plassen carbonate platform s. str. is kimmeridgian to early berriasian at the type-locality mount plassen when the central platform became drowned during the berriasian and was fi nally covered by late berriasian (oblonga calpionellid subzone) calpionellid limestones (gawlick & schlagintweit, 2006). from the late tithonian onwards, a new felix schlagintweit: the dasycladalean algae of the plassen carbonate platform (kimmeridgian-early berriasian)... geologia croatica 189 northward-directed palaeoslope was established. this part of the plassen carbonate platform typically forms the source area for the barmstein limestone. it is important to stress, that almost all the different isolated occurrences of the plassen carbonate platform s. str. comprise only a part of the kimmeridgian-early berriasian lithostratigraphic section. therefore, also the dasycladalean algae content may differ from one locality to the other. for illustrations of the microfacies types of the plassen carbonate platform s. str. see steiger & wurm (1980), schlagintweit et al. (2003, 2005) and gawlick et al. (2009). the dasycladalean algal inventory of the plassen carbonate platform s. str. comprises defi nite 22 (possibly 26) taxa, a number similar compared to the barmstein limestone and the lärchberg carbonate platform. for the systematics see schlagintweit et al. (2005). as already remarked previously, the about three times higher number with respect to the wolfgangsee carbonate platform is easily explained by a complete kimmeridgian-early berriasian succession including many species restricted either to internal or external platform environments. although the overall facies variability in the plassen carbonate platform s. str. is higher then in the lärchberg carbonate platform, the total number of taxa is comparable as in the latter this trend is counterbalanced by a high number of taxa restricted to this platform. 2.4. barmstein limestone the barmstein limestone is interpreted as representing mass -fl ows and turbiditic layers in basinal sediments (oberalm formation) of the tauglboden basin, with components main ly deriving from the adjacent plassen carbonate platform and minor clasts from the underlying substratum (steiger, 1981; gawlick et al., 2005). the barmstein limestone witnesses the collapse of the trattberg rise around the jurassic/cretaceous boundary (gawlick & schlagintweit, 2009; missoni & gawlick, 2011). many of the dasycladalean algae of the barmstein limestone occur with in lithoclasts belonging to different facies zones of the plassen carbonate platform s. str. (reefal, back-reefal, lagoonal environments). based on microfacies aspects (e.g., bored clasts of slope facies; infi ltration of fi ne-siltic matrix between clasts, etc.), an emersion of the northernmost part of the trattberg rise (being the source area of the barmstein limestone in the type-area) was assumed (schlagintweit et al., 2006; schlagintweit, 2008). with an assumed shallowing-upward, clasts of different facies zones (with its different algal contents) could become mixed together. the clasts were already lithifi ed during resedimentation and therefore slightly older as the latest tithonian; clasts of kimmeridgian age of the plassen carbonate platform s. str. are extremely rare. one single fi nding of a specimen of labyrinthina mirabilis weynschenk, however, evidences that occasionally also older strata (e.g., kimmeridgian) were eroded or became uplifted before resedimentation. the reefal bioclasts of the barmstein limestone are assumed to belong to the second reefal belt that formed in late tithonian times at the northern rim of the trattberg rise (gawlick & schlagintweit, 2009) (fig. 2.). within the associated calciturbidites isolated bioclasts of, dasycladales such as clypeina jurassica favre or selliporella neocomiensis (radoičić) occur often exhibiting micritic coatings, indicating more or less synsedimentary transportation. referring to the general lithostratigraphic succession of the plassen carbonate platfrom s. str. at the type-locality mount plassen, the erosion/reworking of the barmstein limefigure 2: distribution of dasycladalean algae within the plassen carbonate platform s. str. the lithostratigraphic column refers to the most complete section of the type-locality mount plassen (schlagintweit et al., 2003, for details). data used additionally are mainly from mount krahstein (see gawlick et al., 2004) and other localities. note that the number of taxa for each unit of the schematized column can not be accumulated to the total number of taxa as some, e.g. salpingoporella pygmaea (gümbel), occur in more than one facies unit. geologia croatica 64/3geologia croatica 190 stone normally did not reach the campbelliella limestones. these mark the major change from the lower tithonian transgressive-regressive cycles of the southern part of the plassen carbonate platform to the upper tithonian closed lagoonal facies, followed by a northward facing second reefal belt (see schlagintweit et al., 2003; schlagintweit & gawlick (2007); gawlick & schlagintweit (2009) (fig. 2)). the absence of campbelliella striata (carozzi) in the barmstein limestone was already observed by steiger (1981, p. 277) and interpreted in terms of a source area where the species could not evolve. as discussed by schlagintweit & gawlick (2007, fi g. 5), this observation can be better explained by the microfacies evolution and succession of the late tithonian closed lagoonal facies at mount plassen, where this species is absent. two exceptions are the occurrences of campbeliella striata (carozzi) at mount hornkogel (gawlick & schlagintweit, 2009) or mount kehlstein (missoni & gawlick, 2011; own observation). referring to the classical defi nition, these sediments at mount hornkogel cannot be included in the barmstein limestone. here, c. striata (carozzi) occurs as resedimented bioclasts, not within lithoclasts. a possible explanation could be that we are dealing with stratigraphically two different levels of “barmstein limestone”: an older one (following the agatha formation) where campbelliella striata (carozzi) may occur and a younger level where it is obviously absent. the older level might be placed into the interval late early tithonian to the early/late tithonian boundary, the younger in the late tithonian (crassicollaria calpionellid subzone) to early berriasian. for example, the fi rst resediments of barmstein limestone at mount tressenstein occur about 175 m below the fi rst occurrences of both calpionella alpina-crassicollaria intermedia (gawlick & schlagintweit, 2009, fi g. 5). in contrast to this “barmstein limestone” assumed to have been deposited in a more southern position on the trattberg rise (gawlick & schlagintweit, 2009), the northern occurrences ewige wand, zwerch wand, jochwand can be placed within the late tithonian crassicollaria subzone. in all these occurrences, campbelliella striata (carozzi) does occur neither as individual bioclast nor as component of reworked lithoclasts. except gyroporella? sp. and chinianella scheympfl ugi hofmann, that both seem to be restricted to the late kimmeridgian southward-facing platform margin, all species known from the plassen carbonate platform s. str. also occur in the barmstein limestone. gen. et sp. indet 2, reported only from the late tithonian closed lagoonal facies of the plassen carbonate platform s. str. as typical algal debris facies within wackestones (schlagintweit & gawlick, 2007, for details) is rather common in the barmstein limestone and occurs also at the type-locality of the plassen carbonate platform s. str., mount plassen. this constellation explains its absence in the resediments of the sillenkopf formation to the south and the northern wolfgangsee carbonate platform; so far gen. et sp. indet. 2 has not been identifi ed from the lärchberg carbonate platform. three taxa, neoteutloporella socialis (praturlon), neoteutloporella obsoleta carozzi and terquemella sp. aff. t. concava bernier are restricted to the late tithonian reefal interval of the plassen carbonate platform s. str. from where these became reworked within the barmstein limestone (schlagintweit, 2010, for details). five (possibly seven) taxa have so far only been observed in the barmstein limestone assuming that these have both a biostratigraphic limitation (lacking in strata older than the late tithonian) and palaeogeographic limitation with an assumed occurrence at the northward-facing reefal margin of the plassen carbonate platform s. str. that became eroded and resedimented. an example is selliporella neocomiensis (radoičić), having its fi rst appearance in the late tithonian (see also granier & bucur, 2010) and being typical for external platform environments (bucur & săsăran, 2005). from the available data it can be assumed that the former platform margin parallel belt where s. neocomiensis (radoičić) was dwelling in an assumed back-reef position (= the north-western edge of the trattberg rise; see missoni & gawlick, 2011, fi g. 25a), has been eroded and resedimented as barmstein limestone within the tauglboden basin. 2.5. lärchberg carbonate platform the facies evolution of the lärchberg carbonate platform is still not known in all details. as outstanding characteristic, contrasting the plassen carbonate platform s. str. and the wolfgangsee carbonate platform, an overall terrigenous input can be stated. it should be noted that the carbonates of the plassen carbonate platform s. str. are highly pure limestones with a cac03 content larger then 99 % (moshammer & lobitzer, 2000). due to new unpublished results, the classical scheme of ferneck (1962) with a basal transgressive series (lofer beds or lofer unit, see also sanders et al., 2007, fi g. 2) passing into a limestone complex, the lärchberg limestone, is completely the other way round. the clastic series represents a late tithonian to?earliest berriasian fi nal coarsening-upward series, with anchispirocyclina lusitanica (egger) as one main characteristic microfossil. the kimmeridgian parts are well documented with labyrinthina mirabilis weynschenk and kilianina? rahonensis foury & vincent, for example from mounts litzelkogel-gerhardstein (e.g., dya, 1992; own observations). the more or less absence of high-energy reefal platform margin deposits, e.g. well documented for the plassen carbonate platform s. str. (e.g., gawlick et al., 2004; auer et al., 2009), points to a different platform geometry, with a less inclined slope. for example, thrombolithic boundstones with abundant tubes of terebella lappiloides münster associated with crescentiella morronensis (crescenti) are a characteristic feature of the kimmeridgian slope deposits of the lärchberg carbonate platform, unreported from both the plassen carbonate platform s. str. and the wolfgangsee carbonate platform (see fig. 49/1 in gawlick et al. 2009). this peculiar facies is directly comparable to the terebella“tubiphytes” association sensu schmid (1996) refered to quiet water depositional settings well below the storm wave base and may in cases be indicative for oxygene depletion. such an assumption would fi t to the interpretation of the sillenkopf basin as a starved basin by missoni & gawlick (2011). in analogy to the northern tethyan occurrences of felix schlagintweit: the dasycladalean algae of the plassen carbonate platform (kimmeridgian-early berriasian)... geologia croatica 191 this peculiar facies, a comparable gentle north ward-facing slope of the lärchberg carbonate platform can be postulated. equivalent to the plassen carbonate platform s. str., also the isolated occurrences of the lärchberg carbonate platform may show differences in the lithostratigraphic column and thus, also does their dasycladalean algal content. for illustrations of the microfacies types of the lärchberg carbonate platform see darga & schlagintweit (1991), dya (1992) and sanders et al. (2007). with 11 species (when including also s. svilajaenis) only recorded from the lärchberg carbonate platform and resedimented in the sillenkopf formation, it is the most individualized character of all three platforms. most of these taxa are reported from marly wackestones of an assumed internal infralittoral environment, zergabriella embergeri (bouroullec & deloffre) from the same palaeoenvironment additionally shows infl uences of fresh-water (e.g., jaffrezo & renard, 1979). cylindroporella? sp. 1 known only from the lärchberg carbonate platform occurs in well-agitated back-reef/open lagoonal facies. the overall terrigeneous input, and partly assumed brackish infl uence of the lärchberg carbonate platform, lacking in the wolfgangsee carbonate platform and plassen carbonate platform, are considered the main infl uencing factors for this discrete microfl ora. 2.6. sillenkopf formation the sillenkopf formation comprises basinal sediments occurring between the plassen carbonate platform s. str. to the north and the lärchberg carbonate platform to the south. type-locality is mts. sillenköpfe in the berchtesgaden alps (missoni et al., 2001). the siliciclastic detritus of the older orogen in the resediments (breccias, calciturbidites) evidences that the basin mainly received material from the south as transport from the north can be excluded in late jurassic times (see for example newest reconstruction for this time interval of missoni & figure 3: aspects of microfacies and microfossils (benthic foraminifers, dasycladales) from the sillenkopf formation of mount sillenköpfe (a–d, e) and the lärchberg carbonate platform (e). a–b: labyrinthina mirabilis weynschenk exhibiting agglutination of siliciclastic grains. sample ber 31-1b-4 and ber 31-1b-1. c: tangential section of salpingoporella pygmaea (gümbel) showing silifi cation. sample ber 31-5b-7. d: oblique section of chinianella scheympfl ugi hofmann showing silification. sample ber 51-5. e: microfacies of the lärchberg formation with silicifi ed oncoids, plant remains (p) and extraclasts (e). mount dietrichshorn, sample die170f. f: silicifi ed oncoid from the sillenkopf formation. sample ber 31-4b. scale bars = 1 mm, except e = 2 mm. a b c d e f geologia croatica 64/3geologia croatica 192 gawlick, 2011, fi g. 24d–e). silicifi ed oncoids reworked in these breccias are a further characteristic feature and are only known from the lärchberg carbonate platform (own observations, fig. 3e–f). the occurrence of labyrinthina mirabilis weynschenk and occasionally kilianina? rahonensis foury & vincent in the coarser breccias layers, indicates that the resediments are mainly of kimmeridgian age. dasycladalean thalli and test of larger foraminifers on occasion show silifi cation (fig. 3c–d). as a further characteristic of the resediments, siliciclastic grains may become incorporated especially in the tests of labyrinthina mirabilis weynschenk (fig. 3a–b), never observed in specimens from the central plassen carbonate platform or the wolfgangsee carbonate platform. dasycladalean algae occur as individual bioclasts in the breccias comprising a handful of taxa known from the whole plassen carbonate platform system (tab. 1). the occurrence of the alga steinmanniporella svilajaensis (sokač & velić) especially in proximal deposits of the sillenkopf formation, that is typical for the kimmeridgian external facies of the lärchberg carbonate platform (e.g., mounts litzelkogel-gerhardstein), can also be considered an indication for the southern source area of the lärchberg carbonate platform (see tab. 1). the distinctly reduced algal content compared to the barmstein limestone is due to mostly synsedimentary resedimentation as individual bioclasts (often with taxa typical for external habitats) and the lack of mixed assemblages from clasts of different facies zones. in some aspects such as the co-occurrence of dasycladales with the foraminifers protopeneroplis striata weynschenk and labyrinthina mirabilis weynschenk and the presence of ooids, the resediments of the sillenkopf formation are similar to those of the seekarspitz limestone. the siliciclastic infl ux evidenced in the sillenkopf formation (missoni et al., 2001) is lacking in the latter as well as in the barmstein limestone. 3. taxonomic inventory the occurring taxa (tab. 1) are illustrated and listed in alphabetical order including short comments on occurrences and distribution in the northern calcareous, information on semiquantitative abundances (rare/common/abundant); in some cases taxonomic remarks are provided in addition. campbelliella striata (carozzi) (pl. 1, fig. a) well recorded from the late kimmeridgian to early late tithonian of the plassen carbonate platform s. str. and rare from the lärchberg carbonate platform. individual specimens may occur in the upper kimmeridgian reefal facies; at mount plassen the species occurs in monospecifi c assemblages and great abundances (fenninger & holzer, 1972; schlagintweit et al., 2003). occurrences: barmstein limestone (rare), plassen carbonate platform s. str. (common to abundant), lärchberg carbonate platform (rare). chinianella scheympfl ugi hofmann (pl. 1, fig. n, text-figure 3d) this alga occurs in well-agitated back-reef to open lagoonal facies. it was described from the middle to late tithonian ernstbrunn limestone of lower austria by hofmann (1994) and has so far been recorded from poland, greece and crimea/ukraine (schlagintweit, 2011). in the northern calcareous alps it is, besides from tithonian strata, also recorded from the kimmeridgian of the plassen carbonate platform s. str., e.g. mount rettenstein, or the sillenkopf formation. occurrences: plassen carbonate platform s. str. (common), sillenkopf formation (rare), lärchberg carbonate platform (rare). plate i dasycladales from the late jurassic-earliest cretaceous of the northern calcareous alps: plassen carbonate platform s. str. (a, f–g, l, n), wolfgangsee carbonate platform (o–p), lärchberg carbonate platform (c–d, h–i, k), barmstein limestone (b, e, m) a campbelliella striata (carozzi), mount trisselwand, sample mt 144. b, e clypeina aff . estevezii granier, mount zwerchwand, sample b 86 (b) and mount trisselwand, sample t 166-3 (e). c–d cylindroporella? sp. 1, mount lärchberghörndl, sample ks 71. f clypeina loferensis schlagintweit, dieni & radoičić (above) and clypeina jurassica favre (below), mount plassen, sample a 3168. g clypeina loferensis schlagintweit, dieni & radoičić, mount plassen, sample a 3168. h clypeina catinula carozzi, mount lärchberghörndl, sample lof 1. i cylindroporella? sp. 2, mount dietrichshorn, sample die 170. j clypeina cf. marteli emberger, locality postalm, sample h-14. k–l clypeina parasolkani farinaci & radoičić, mount dietrichshorn, sample gs 135f and mount plassen, sample a 3167–1. m clypeina aff . solkani conrad & radoičić, mount ewige wand, sample e 36. n chinianella scheympfl ugi hofmann, mount plassen, sample pl 70d. o–p dissocladella? n. sp., mount jainzen, samples d 576 and d 575. felix schlagintweit: the dasycladalean algae of the plassen carbonate platform (kimmeridgian-early berriasian)... geologia croatica 193 a b c d e f g h i j l k m n o p geologia croatica 64/3geologia croatica 194 clypeina catinula carozzi (pl. 1, fig. h) only known from the late tithonian (?earliest berriasian) of the lärchberg carbonate platform (schlagintweit & ebli, 2000, for details). occurrences: lärchberg carbonate platform (common). clypeina aff . estevezii granier (pl. 1, figs. b, e) originally described from the berriasian of southern spain (granier, 1988), it has also been recorded from the earliest berriasian of sardinia (dieni & radoičić, 2000). in the northern calcareous alps it occurs in late tithonian strata. occurrences: barmstein limestone (rare), plassen carbonate platform s. str. (rare). mention must be made, that from the tithonian-berriasian torinosu limestone of japan endo (1961) described a new taxon as “calcisphera” jurassica that seems to belong to a shallow tangential section of a clypeina species with numerous and distally unfused laterals such as for instance c. estevezii or others. clypeina jurassica favre (pl. 1, fig. f pars) a widespread taxon that occurs in great abundances in closed/ open lagoonal wacke-/packstones. depending on the platform morphology, individual verticil fragments are also found in external platform facies. the common occurrence in calciturbidites of the barmstein limestone can be explained by the retrograde erosion of the platform margins affecting also lagoonal environments. concerning the systematic, c. jurassica favre vs. clypeina sulcata (alth) see comments in schlagintweit et al. (2009). occurrences: wolfgangsee carbonate platform (rare), barmstein limestone (common), plassen carbonate platform s. str. (abundant), sillenkopf formation (rare), lärchberg carbonate platform (abundant). clypeina loferensis schlagintweit, dieni & radoičić (pl. 1, fig. f pars, g) illustrated from the lärchberg carbonate platform as actinoporella podolica (alth) by dya (1992). occurrences: barmstein limestone (common), plassen carbonate platform s. str. (common), lärchberg carbonate platform (abundant). clypeina cf. marteli emberger (pl. 1, fig. j) very rare sections with stellate outline, elongated laterals only fused at the proximal parts and comparable small main axis can be referred with some restrictions to clypeina marteli emberger (e.g., bassoullet et al., 1978, pl. 38, fi g. 1; dieni & radoičić, 2000, pl. 5, fi gs. 6–7). occurrences: barmstein limestone (rare, e.g., gawlick et al., 2005, fi g. 13/5), possible occurrences: plassen carbonate platform s. str., lärchberg carbonate platform. clypeina cf. parasolkani farinacci & radoičić (fig. 1, figs. k–l) this species was originally described from the berriasian of turkey (farinacci & radoičić, 1991). a longitudinal section cutting 15 succesive verticils has been illustrated by steiger & wurm (1980, pl. 26, fi g. 2) as salpingoporella annulata carozzi from the late kimmeridgian of the plassen carbonate platform s. str. of mount krahstein. occurrences: barmstein limestone (common), plassen carbonate platform s. str. (common), lärchberg carbonate platform (common). clypeina aff . solkani conrad & radoičić (pl. 1, fig. m) this clypeina with massive calcifi cation can be compared with clypeina solkani conrad & radoičić. it typically occurs in the upper tithonian wackestones of the closed lagoonal facies. according to granier & deloffre (1993) this species should have an assumed total stratigraphic range of oxfordian-albian, sokač (1996, p. 26) indicates a hauterivian to barremian age doubting both older and younger occurrences. occurrences: limesone (common), plassen carbonate platform s. str. (common), lärchberg carbonate platform (common). cylindroporella? sp. 1 (pl. 1, figs. c–d) this alga has been detected only at mount lärchberghörndl in well washed-out packstones of a back-reef to open lagoonal facies; age: late kimmeridgian or tithonian. such a microcrystalline calcifi cation is known from other cylindriporelliform dasycladales: cylindroporella taurica conrad & varol, 1990 (albian of turkey) and vederosella? alimani dragastan, 1999 (late hauterivian of romania). similar forms were illustrated also by bucur et al. (2000) from the valanginian-hauterivian of turkey. occurrences: lärchberg carbonate platform (rare). cylindroporella? sp. 2 (pl. 1, fig. i) a very rare alga occurring in wackestone facies and reported from the barmstein limestone, the plassen carbonate platform s. str. and the lärchberg carbonate platform. the tangential section shown in plate 1, figure i can be compared with cylindroporella faronensis masse, bucur, virgone & delmasso, 1999 from the berriasian-valanginian of se france. occurrences: barmstein limestone (rare), plassen carbonate platform s. str. (rare), lärchberg carbonate platform (rare). dissocladella? n. sp. (pl. 1, figs. o–p) this tiny dasycladale with supposedly two orders of laterals is so far only reported from the wolfgangsee carbonate platform of mount jainzen where it typically occurs in peri-reefelix schlagintweit: the dasycladalean algae of the plassen carbonate platform (kimmeridgian-early berriasian)... geologia croatica 195 fal limestones. the strong recrystallization and so far poor available material does not allow for a detailed taxonomic description at the moment. occurrences: wolfgangsee carbonate platform (rare). deloff rella quercifoliipora granier & michaud (pl. 2, fig. a) this species has so far only been reported from the lärchberg carbonate platform of mount dietrichshorn associated besides others, with zergabriella embergeri (bouroullec & deloffre). occurrences: lärchberg carbonate platform (rare). gen. et sp. indet 1 (pl. 2, fig. b) very rare dasycladalean alga showing thallus annulation and numerous laterals. shape of laterals, orders and connection to the main axis unknown. the illustrated specimens comes from mount dietrichshorn; age: tithonian? occurrences: lärchberg carbonate platform (rare). gen et sp. indet 2 (pl. 2, figs. c–d) this alga typically forms monospecifi c debris facies (wackestones) (see schlagintweit & gawlick, 2007, for details). it is recorded from upper tithonian wackestones of the plassen carbonate platform s. str. and equivalent clasts resedimented in the mass-fl ows of the barmstein limestone. details of this alga showing a comparable wide main axis and segmentation recalling the genus neomizzia levy, are unknown. occurrences: barmstein limestone (abundant), plassen carbonate platform s. str. (common). gen et sp. indet 3 (pl. 2, fig. g) very rare and large dasycladale with massive calcifi cation and numerous primaries. the proximal narrow primaries with a peduncle then gently widening and clusters of secondaries point to the genus triploporella steinmann. occurrences: late tithonian barmstein limestone of mount sandling. griphoporella jurassica (endo) (pl. 2, fig. e) rather widespread form in reefal platform margin deposits occurring often as debris. for the taxonomy see bucur & schlagintweit (2009). occurrences: wolfgangsee carbonate platform (rare), barmstein limestone (common), plassen carbonate platform s. str. (common) and lärchberg carbonate platform (rare). gyroporella? sp. (pl. 2, figs. h, j) so far, this taxon has only been reported from upper kimmeridgian platform margin deposits of mount krahstein, belonging to the plassen carbonate platform s. str. (schlagintweit & ebli, 1999, for details). occurrences: plassen carbonate platform s. str. (rare). humiella catenaeformis (radoičić) (pl. 2, fig. i) this alga was so far unknown from the northern calcareous alps, it is very rarely reported only from the late tithonian barmstein limestone. note that in the dinarids, husinec & sokač (2006) established a clypeina parasolkanihumiella catenaeformis interval zone (berriasian-earliest valanginian). the stratigraphic relevance was already discussed by sokač (1987) previously. the shown specimen comes from the barmstein limestone of mount zwerchwand intercalated in calpionellid wackestones with crassicollaria intermedia (gawlick et al., 2010, for details). therefore, the fi rst appearance of humiella catenaeformis (radoičić) has to be changed from berriasian to late tithonian. occurrences: barmstein limestone (rare). linoporella? sp. (pl. 3, figs. a–b) this rare alga is known only from the (lower) tithonian of the plassen carbonate platform s. str. where it occurs in well washed-out packstones of a back-reef to open lagoonal facies. occurrences: barmstein limestone (rare), plassen carbonate platform s. str. (rare). neoteutloporella socialis (praturlon) (pl. 3, fig. c) neoteutloporella obsoleta carozzi (pl. 3, fig. d) restricted to the upper tithonian reefal interval of the plassen carbonate platform s. str. where it became resedimented northwards within the barmstein limestone (see schlagintweit, 2010, for details). lacking at the mt. barmsteine type-locality, n. socialis (praturlon) was described by fenninger (1972) from the so-called “barmsteinkalkbank b2” of the osterhorn mountains. thus, it has a restricted palaeogeographic occurrence within the northern calcareous alps and also a stratigraphic importance as it lacks in strata older than the late tithonian. n. socialis (praturlon) and n. obsoleta carozzi are lacking in the lärchberg carbonate platform as this second reefal interval seems to be absent there. occurrences: barmstein limestone (common), plassen carbonate platform s. str. (rare). neogyroporella? gawlicki schlagintweit (pl. 3, figs. e–f) restricted to the lärchberg carbonate platform (schlagintweit, 2005). according to barattolo et al. (2008), the genus neogyroporella yabe & toyama could represent a synonym of holosporella pia and consequently n.? geologia croatica 64/3geologia croatica 196 gawlicki schlagintweit a representative of this genus. it should be mentioned, that this alga has so far been recorded only from the northern calcareous alps and within an upper jurassic pebble from the losenstein formation (schlagintweit, 1991, pl. 1, fi g. 7). occurrences: lärchberg carbonate platform (common). otternstella lemmensis (bernier) (pl. 3, fig. g) typical alga of the closed lagoonal facies, occurring in upper tithonian wackestones with clypeina species, rajkaella bartheli (bernier) and salpingoporella annulata carozzi. occurrences: barmstein limestone (rare), plassen carbonate platform s. str. (rare), lärchberg carbonate platform (rare). petrascula bursiformis (ettalon) (pl. 3, fig. h, text-figure 4) common species, especially in the upper kimmeridgian platform reefal interval (e.g. mount jainzen, mount krahstein, mount rettenstein). for the occurrences in the barmstein limestone it is unclear whether these derive from the upper kimmeridgian or late tithonian reefal intervals. the occurrence of three orders of laterals in the stalk part of the thallus is well recorded (bernier, 1979, 1984; bucur & săsăran, in press). thin-sections prepared successively from the same piece of sample have shown that the thinner proximal part of the stalk is characterized by a reduced number of presumably only two orders of laterals (fig. 4a). it must be noted that in the fundamental work of bassoullet et al. (1978) the specimens of “petrascula bursiformis” shown in plate 24, fi gs. 1–5, 7–8 have been provided by bernier. in his revisional work on the genus petrascula one year later, bernier (1979) assigned the specimen shown in pl. 24, fi g. 2 in bassoullet et al. (1978) as holotype for the new species petrascula guembeli; also the specimen illustrated in pl. 24, fi g. 1 belongs to this species. occurrences: wolfgangsee carbonate platform (rare), barmstein limestone (rare), plassen carbonate platform s. str. (common), sillenkopf formation (?). petrascula guembeli bernier (pl. 3, figs. i–j, pl. 4, fig. j) rare specimens only recorded from the barmstein limestone (mount barmsteine, mount sandling, mount trisselwand). this species was described by bernier (1979) from the late kimmeridgian of switzerland. the well-calplate 2 dasycladales from the late jurassic-earliest cretaceous of the northern calcareous alps: plassen carbonate platform s. str. (c, h, j), lärchberg carbonate platform (a–b), barmstein limestone (d–g, i). a deloff rella quercifoliipora granier & michaud, mount dietrichshorn, sample die 170. b gen. et sp. indet. 1, mount dietrichshorn, sample gag 21b. c gen. et sp. indet. 2, mount trisselwand, sample mt 614. d gen. et sp. indet. 2, mount barmsteine, sample ber 30-2b-3. e griphoporella jurassica (endo), mount zwerchwand, sample b 87. f pseudotrinocladus piae (dragastan), mount zwerchwand, sample b 45. g gen. et sp. indet. 3. note a bush of three secondaries (arrow). mount sandling, sample d 765. h, j gyroporella? sp., mount krahstein, samples krah 122–5, 122–9. i humiella catenaeformis (radoičić), mount zwerchwand, sample b 82. figure 4a–d: sections through diff erent levels of the thallus stipe of petrascula bursiformis (ettalon), mount jainzen, wolfgangsee carbonate platform. all specimens are from diff erent thin-sections of the same sample. compare the diff erent morphological aspect of the primaries (a versus d). in a (assumed lower portion of the stipe), only two orders of laterals are discernible. d = outer diameter, d = inner diameter, w = number of primaries. a b c d felix schlagintweit: the dasycladalean algae of the plassen carbonate platform (kimmeridgian-early berriasian)... geologia croatica 197 a b c d e f g h i j geologia croatica 64/3geologia croatica 198 cifi ed stalk (pl. 4, fig. j, fi gured as thyrsoporella alpina dragastan & richter in gawlick et al., 2005) shows the three order of laterals, whereas in the head mostly only the last order laterals are preserved (pl. 3, fig. i). in rare cases, parts of the fi rst and second order laterals may be preserved also in the head portion (pl. 3, fig. j). the stratigraphy of p. guembeli bernier is generally indicated as kimmeridgian (bucur, 1999, tab. 9). concerning the spe cimens in the barmstein limestone, it is unclear whether these belong to the upper kimmeridgian or upper tithonian reefal interval. occurrences: barmstein limestone (rare). pseudotrinocladus piae (dragastan) (pl. 2, fig. f) very rare and large alga with numerous pores (laterals?) so far recorded from the late tithonian barmstein limestone and the plassen carbonate platform s. str.. this alga was originally described from late tithonian of romania (dragastan, 1971, 1989). radoičić (2005) considered p. piae (dragastan) a synonym of griphoporella? perforatissima carozzi and preferred a udoteacean rather then a dasycladalean nature, a view that cannot be commented on the basis of the available sections. the irregular denticulated transition of the calcifi ed part towards the central hollow could be an indication for such an interpretation; in this case the central part would correspond to a decalcifi ed or not calcifi ed medullary zone. occurrences: barmstein limestone (rare), plassen carbonate platform s. str. (rare). rajkaella bartheli (bernier) (pl. 4, fig. a) typical alga of the closed lagoonal facies. in the lärchberg carbonate platform, wackestones with abundant debris of this alga occur associated with the larger benthic foraminifer anchispirocyclina lusitanica (egger). occurrences: barmstein limestone (rare), plassen carbonate platform s. str. (rare), lärchberg carbonate platform (common). rajkaella sp. (pl. 4, fig. b) occurrence: lärchberg carbonate platform (rare). salpingoporella annulata carozzi (pl. 4, fig. f) one of the most widespread species in the plassen carbonate platform sensu lato occurring in closed and open lagoonal limestones. occurrences: wolfgangsee carbonate platform (rare), barmstein limestone (common), plassen carbonate platform s. str. (common), sillenkopf formation (rare), lärchberg carbonate platform (common). salpingoporella aff . dinarica radoičić (pl. 4, fig. c) occurrences: only known from the late tithonian?-early berriasian? of the lärchberg carbonate platform (mount dietrichshorn) (rare). salpingoporella pygmaea (gümbel) (pl. 4, fig. e, text-figure 3c) one of the most widespread species in the plassen carbonate platform sensu lato. this alga is restricted to agitated peri-reefal platform margin deposits; therefore s. pygmaea is comparable rare in the lärchberg carbonate platform. according to carras et al. (2006), salpingoporella johnsoni (dragastan) and salpingoporella enayi bernier, recorded from the plassen carbonate platform s. str. (schlagintweit & ebli, 1999; schlagintweit et al. 2005) are synonyms of s. pygmaea. occurrences: wolfgangsee carbonate platform (common), barmstein limestone (rare), plassen carbonate platform s. str. (common), sillenkopf formation (common), lärchberg carbonate platform (rare). salpingoporella sellii (crescenti) (pl. 4, fig. d) due to the unusual microgranular pattern of calcifi cation, the attribution of this alga to the genus salpingoporella is ambiguous (e.g., carras et al., 2006, p. 460). consequently, when calcifi cation pattern are considered of generic importance, also salpingoporella dinarica radoičić must be treated in an adequate manner. occurrences: barmstein limestone (rare), plassen carbonate platform s. str. (rare), lärchberg carbonate platform (rare). plate 3 dasycladales from the late jurassic-earliest cretaceous of the northern calcareous alps: plassen carbonate platform s. str. (a–c, d, h), lärchberg carbonate platform (e–f), barmstein limestone (g, i–j). a–b linoporella? sp., mount plassen, samples pl 80 and pl 73a. c neoteutloporella socialis (praturlon), mount trisselwand, sample mt 356. d neoteutloporella cf. obsoleta (carozzi), locality knallalm, sample mr 111. e–f neogyroporella? gawlicki schlagintweit, mount litzelkogel, sample a 190 and mount dietrichorn, sample die 170–2. g otternstella lemmensis (bernier), mount sandling, d 775. h petrascula bursiformis (ettalon), mount rettenstein, sample rö 364. i–j petrascula guembeli bernier, mount sandling, sample d 190 and mount trisselwand, sample mt 855 (r1 to r3 = primary, secondary, tertiary laterals). felix schlagintweit: the dasycladalean algae of the plassen carbonate platform (kimmeridgian-early berriasian)... geologia croatica 199 a b c d e f g h i j geologia croatica 64/3geologia croatica 200 selliporella neocomiensis (radoičić) (pl. 4, figs. g–h) large dasycladale with stratigraphic importance in the northern calcareous alps as it is not reported from strata older then the late tithonian (bucur & săsăran, 2003). previously it has been reported from mount sandling by fenninger & holzer (1972, pl. 18/2); in the barmstein limestones the star-shaped sections of the secondary laterals are common in some clasts (schlagintweit & gaw lick, 2007, for details). occurrences: barmstein li me stone (common). steinmanniporella svilajaensis (sokač & velić) (pl. 5, figs. d–e) this alga is most typical for the kimmeridgian external facies of the lärchberg carbonate platform, often associated with corals. resedimented it occurs also in the proximal sillenkopf formation (compare fig. 49/2 in gawlick et al., 2009). the species anthracoporella torinosensis described by endo from the tithonian-berriasian reefal facies of the torinosu limestone of japan might also belong to the genus steinmanniporella bucur, granier & schlagintweit, but a species different from s. svilajaensis. occurrences: lärchberg carbonate platform (common), sillenkopf formation (rare to common). suppiluliumaella cf. delphica (carras) (pl. 4, figs. i) rather large dasycladale originally described as clypeina? delphica from kimmeridgian reefal platform margin deposits of greece (carras, 1989) trasferrred to the genus suppiluliumaella elliott by senowbari-daryan et al. (1994) based on material from the late tithonian of sicily/ italy. occurrences: wolfgangsee carbonate platform (rare). suppiluliumaella? cf. fl orifera (bernier) (pl. 5, figs. a–b) reported as suppiluliumaella tuberifera (sokač & nikler) by dya (1992) from the lärchberg carbonate platform occurring in poorly washed-out carbonates with scattered ooids marking a depositional realm at the transition from poorly to well agitated habitats. fenninger (1978) reported the species from the plassen carbonate platform s.str. of mount trisselwand. occurrences: lärchberg carbonate platform (rare), plassen carbonate platform (rare), barmstein limestone (rare). terquemella sp. 1 (pl. 5, fig. f) small representative of terquemella with low number of cysts, so far only reported from the lärchberg carbonate platform. terquemella sp. 2 aff . concava bernier (pl. 5, fig. g) taxon typically for the upper tithonian platform margin deposits (details see in schlagintweit et al., 2005). triploporella? sp. (pl. 5, fig. i) rare large alga, known only as debris from the barmstein limestone. vermiporella? tenuipora conrad (pl. 5, figs. j–k) an alga incertae sedis, described originally from the lower cretaceous (urgonian) of switzerland (conrad, 1970); it has been reported later also from upper cretaceous strata (radoičić, 1972; schlagintweit, 1992). its stratigraphic range can now be extended into the tithonian. occurrence: only from the lärchberg carbonate platform (mts. dietrichhorn and lärchberghörndl-lofer kalvarienberg). zergabriella embergeri (bouroullec & deloffre) (pl. 5, figs. h) so far only reported from the lärchberg carbonate platform (mount dietrichshorn: darga & schlagintweit, plate 4 dasycladales from the late jurassic-earliest cretaceous of the northern calcareous alps: wolfgangsee carbonate platform (i), lärchberg carbonate platform (a–d, f), barmstein limestone (e, g–h, j). a rajkaella bartheli (bernier), mount dietrichshorn, sample gag 29a. b rajkaella sp., mount lärchberghörndl, sample lof 1. c salpingoporella aff . dinarica radoičić, mount dietrichshorn, sample die-170. d salpingoporella sellii (crescenti), mount dietrichshorn, sample die 156. e salpingoporella pygmaea (gümbel), mount trisselwand, sample mt 54. f salpingoporella annulata carozzi, mount dietrichshorn, sample die 156. g–h selliporella neocomiensis (radoičić), mount sandling and mount trisselwand, samples d 200 and mt 367. i suppiluliumaella cf. delphica (carras), mount falkenstein, samples uk 61 and uk 13a. j petrascula guembeli bernier, mount barmstein, sample b 16. felix schlagintweit: the dasycladalean algae of the plassen carbonate platform (kimmeridgian-early berriasian)... geologia croatica 201 a b c d e f g h i j geologia croatica 64/3geologia croatica 202 plate 5: dasycladales from the late jurassic-earliest cretaceous of the northern calcareous alps: plassen carbonate platform s. str. (c, g), lärchberg carbonate platform (a–b, d–f, h, j–k), barmstein limestone (i). a–b suppiluliumella? cf. fl orifera (bernier) in ooidal wacke-/packstone, mount lärchberghörndl, sample 7/4 of dya (1991). c unknown dasycladale (suppiluliumaella? sp.) with three orders of laterals (r1–3 = primary, secondary, tertiary ramifi cations/ laterals), mount trisselwand, sample mt 293. d–e steinmanniporella svilajaensis (sokač & velić), mount gerhardstein, sample dm 75. f terquemella sp. 1, mount litzelkogel, sample a 182. g terquemella sp. 2 aff . concava bernier, mount plassen, sample pl 58a. h zergabriella embergeri (bouroullec & deloffre), mount dietrichshorn, sample die 170. i triploporella? sp., mount ewige wand, sample e 384. j–k vermiporella? tenuipora conrad, longitudinal-tangential and transverse section, sample die ix-170, mount dietrichshorn and sample lof 6, mount lofer kalvarienberg. a b d ec gf h i j k felix schlagintweit: the dasycladalean algae of the plassen carbonate platform (kimmeridgian-early berriasian)... geologia croatica 203 1991; mount hochkranz: dya, 1992) where it occurs in the fi nal shallowing upwards-phase with fi ne terrigeneous infl uence. for general distribution of this alga see recent synonymy provided by granier (2010). z. embergeri (bouroullec & deloffre) is often reported to co-occur with characean algae and can be considered an indicator for brack ish water infl uences (e.g., peybernès, 1979; conrad, 1977; wyssling, 1986; granier, 1988). refering to the review of rasser & fenninger (2002), four more taxa, not incorporated into the present work, are listed. these were either incorrectly determined or no proofable evidences for their real occurrence are available or were reported from strata that from a palaeogeographic point of view are totally different from the plassen carbonate platform and therefore must be excluded: salpingoporella grudii radoičić: in our opinion, the fi gurations of dya (1992) from the lärchberg carbonate platform rather belong to thallus fragments of salpingoporella annulata carozzi, one of the most widespread taxa in the plassen carbonate platform sensu lato (see tab. 1), exhibiting a pronounced distal widening of the laterals. in our own material we fi nd wackestones with abundant specimens of s. annulata carozzi where it can be seen, that depending on the distal branch opening/compression, different sections are prevailing some of which could assume to belong to salpingoporella grudii radoičić. however, so far no sections of salpingoporella grudii radoičić with the typical horizontally compressed branches have been fi gured in the alpine literature. all other citations of salpingoporella grudii radoičić from the northern calcareous alps have not been provided with illustrations (fenninger & holz er, 1972), thus, generally puting some doubt on it, since we have never observed the mentioned taxon in the material investigated from various alpine localities. actinoporella podolica (alth): the fi gurations of actinoporella podolica (alth) given by dya (1992) in fact belong to clypeina loferensis a taxon described recently by schlagintweit et al. (2010). the rare other reports of actinoporella podolica (alth) have not been provided with illustrations. for example, the species has been mentioned by fenninger (1967) from the type-locality of the plassen formation; in the framework of detailed recent investigations carried out, this species has not been observed (schlagintweit et al., 2003, 2005). again, clypeina loferensis schlagintweit, dieni & radoičić occurs in the clos ed lagoonal facies at mount plassen (pl. 1, fig. g). acicularia elongata carozzi: it has been reported by dya (1992) from the plassen carbonate platform of mount untersberg and the lofer area. however, no illustrations have been provided so that a fi nal evaluation is not possible. according to our own material, the species in question has never been observed in the plassen carbonate platform. elongated aciculariacean-type sections can be misinterpreted as tangential sections of individual articles of neoteutloporella socialis (praturlon) (schlagintweit, 2010). pseudocymopolia pluricellata bakalova: the species pseudocymopolia pluricellata bakalova has been mentioned by schlagintweit (1991) from upper jur assic pebbles resedimented in the albian-cenomanian losenstein formation of the “kalkalpine randzone”. as the source area of these shallow water limestones, an “exotic ridge” situated north of the northern calcareous alps is assumed (e.g., gaupp, 1983). thus, it has to be eliminiated from the fl ora list provided by rasser & fenninger (2002) referring to the plassen carbonate platform. instead, the dasycladales occurring in pebbles of the outer carpathian pieniny klippen zone (e.g., misik & sykora, 1981; sotak & misik, 1993) should be compared directly with tho se from the losenstein formation (gaupp, 1983; schla g intweit, 1991). apart from the four mentioned taxa, salpingoporella enayi bernier and salpingoporella johnsoni dragastan, both listed by rasser & fenninger (2002), too, are considered synonyms of salpingoporella pygmaea (gümbel) (carras et al., 2006). 4. conclusions the alpine plassen carbonate platform represents a system of several isolated platforms separated by basins. these platforms differ in parts in their geometries, sedimentological evolution, subsidence history and faunal and fl oral content. as a consequence of this, the distribution of dasycladalean algae within the plassen carbonate platform is not homogeneous but shows several peculiarities. the most discrete inventory is reported from the lärchberg carbonate platform with its overall terrigeneous input. also the barmstein limestone shows independent composition relating to parts of the plassen carbonate platform that have been eroded. the dasycladalean fl ora known so far consists of 42 (40 when excluding problematic forms vermiporella? tenuipora and pseudotrinocladus piae). from these, three taxa are treat ed as gen. et sp. indet.; some of which could represent new species to be described on the basis of more material. the main reason for the comparable rich association of dasycladales is, that there is a multiple change of facies with a great variety of different platform paleoenvironments each with typical algal associations. furthermore, some typical environments, e.g. reefal and peri-reefal facies, occur twice (late kimmeridgian and latest tithonian-?earliest berriasian). in this case, there are taxa that occur in both reefal intervals, others being restricted either to one or the other. the fl ora consists mostly of ubiquistic species and some species that can be considered typical for southern tethyan communites such as salpingoporella sellii (crescenti), humiella catenaeformis (radoičić) or steinmanniporella svilajaensis (sokač & velić). the species neogyro porella? gawlicki schlagintweit is so far only reported from the northern calcareous alps, and could therefore represent an endemic taxon. the present study demonstrates that the assessment and analysis of the micropaleontological inventories, exemplifi ed with dasycladalean algae, can be a helpful palaeogeographical tool to differentiate different late jurassic carbonate platforms and their resediments in the northern calca reous alps as part of the northwestern tethyan realm. geologia croatica 64/3geologia croatica 204 acknowledgement without the numerous thin-sections provided by hans-jürgen gaw lick, sigrid missoni and matthias auer (leoben), this work wouldn´t have been possible. many thanks to both reviewers ioan bucur (cluj-napoca) and filippo barattolo (naples) for their helpful comments. thanks also to julie robson for the english review of the paper. references auer, m., suzuki, s., schlagintweit, f. & gawlick, h.j. (2009): spatial and temporal development of siliceous basin and shallow-water carbonate sedimentation in oxfordian northern calcareous alps.– facies, 55, 63–87. doi: 10.1007/s10347-008-0155-3 barattolo, f., cozzi, a. & romano, r. (2008): new dasycladalean algae from the middle norian (upper triassic) of northern italy (mt. pramaggiore, carnic prealps).– facies, 54, 549–580. doi: 10.1007/s10347-008-0146-4 bassoullet, j.p., bernier, p., conrad, m.a., deloffre, r. & jaffrezo, m. (1978): les algues dasycladales du jurasique et du crétacé.– géobios, mém. spec., 3, 1–333. bernier, p. (1979): le genre petrascula gümbel 1873, algue dasycladacée : émendation, révision des espèces du genre, création de nouvelles espèces.– géobios, 12/6, 839–861. bernier, p. (1984): les formations carbonatées du kimmeridgien et du portlandien dans le jura méridional. stratigraphie, micropaléontologie, sédimentologie.– doc. lab. geol., 92, 1–803. bucur, i.i. (1999): stratigraphic signifi cance of some skeletal algae (dasycladales, caulerpales) of the phanerozoic.– in: farinacci, a. & lord, a.r. (eds.): depositional episodes and bioevents, palaeopelagos spec. pub., 2, 53–104. bucur, i.i., koch, r., kirmaci, z.m. & tasli, k. (2000): les algues dasycladales du crétacé inférieur (calcaire de berdiga) de kircaova (région de kale-gümüshane, ne turquie).– rev. paléobiol., 19/2, 435–463. bucur, i.i. & săsăran, e. (2003): selliporella neocomiensis radoićič, 1975 (non 1963), nov. comb., a lower cretaceous dasyclad alga from the tethyan realm.– acta micropal. sinica, 20, 57–66. bucur, i.i. & săsăran, e. (2005): relationship between algae and environment: an early cretaceous case study, trascău mountains, romania.– facies, 51, 274–286. doi: 10.1007/s10347-005-001-9 bucur, i.i. & săsăran, e. (in press): large dasycladalean algae from upper jurassic limestone deposits of the apuseni mountains (romania) – habitat and depositional environment.– geodiversitas. bucur, i.i. & schlagintweit, f. (2009): taxonomic revision of pseudoepimastopora endo 1960 and its upper jurassic to lower cretaceous representatives.– abstract book ifaa 6th reg. symp. 1–5 july 2009 milan, 20–21. carras, n. (1989): clypeina? delphica (alghe calcare, dasicladali) nel malm dell´area del parnaso (grecia).– boll. soc. paleont., 28/1, 63–70. carras, n., conrad, m.a. & radoičić, r. (2006): salpingoporella, a common genus of mesozoic dasycladales (calcareous green algae).– rev. paléobiol., 25/2, 457–517. conrad, m.a. (1970): vermiporella? tenuipora n. sp., une algue incertae sedis des calcaires urgoniens de la région genevoise.– c. r. séances soc. phys. hist. nat., 5, 37–42. conrad, m.a. (1977): the lower cretaceous algae in the area surrounding geneva (switzerland): biostratigraphy and depositional environments.– in: flügel, e. (ed.): fossil algae. new york, springer, 295–300. conrad, m.a. & varol, b. (1990): cylindroporella taurica, n. sp., urge to review different patterns of calcifi cation in the mesozoic dasycladales (green algae).– arch. sci. genève, 43, 193–214. darga, r. & schlagintweit, f. (1991): mikrofazies, paläontologie und stratigraphie der lerchkogelkalke (tithon-berrias) des dietrichshorns (salzburger land, nördliche kalkalpen).– jb. geol. b.–a., 134, 205–226. dieni, i. & radoićič, r. (2000): clypeina dragastani sp. nov., salpingoporella granieri sp. nov. and other dasycladalean algae from the berriasian of eastern sardinia.– acta palaeont. romaniae, 2 (1999), 105–123. dragastan, o. (1971): new algae in the upper jurassic and lower cretaceous in the bicaz valley, east carpathians (romania).– rev. espan. micropal., 3, 155–192. dragastan, o. (1989): calcareous algae (new and revised), microproblematicae and foraminiferida of jurassic – lower cretaceous deposits from the carpathian area.– rev. espan. micropal., 21, 5–65. dragastan, o. (1999): early cretaceous algae of aliman (south dobrogea): a revision and description of two new species from east carpathians.– acta palaeont. romaniae, 2, 125–137. dya, m. (1992): mikropaläontologische und fazielle untersuchungen im oberjura zwischen salzburg und lofer.– unpubl. phd thesis, techn. univ. berlin, 138 p. endo, r. (1961): calcareous algae from the jurassic torinosu limestone of japan.– sci. rep. saitama univ. ser. b comm, 53–75. farinacci, a. & radoićič, r. (1991): late jurassic-early cretaceous dasycladales (green algae) from the western pontides, turkey.– geol. rom., 27, 135–165. fenninger, a. (1967): riffentwicklung im oberostalpinen malm.– geol. rdsch., 56, 171–185. fenninger, a. (1972): die fauna und flora der barmsteinkalk-bank b2 im raume des trattberges (osterhorngruppe, salzburg).– ber. haus nat salzburg, 3, 10–23. fenninger, a. (1978): neue faunenund florenelemente aus den plassenkalken der trisselwand (totes gebirge, steiermark).– mitt. natwiss. ver. steiermark, 108, 115–119. fenninger, a. & hötzl, h. (1967): die mikrofauna und –fl ora des plassenund tressensteinkalkes der typlokalität (nördliche kalkalpen).– n. jb. geol. paläont. abh., 128, 1–37. fenninger, a. & holzer, h.l. (1972): fazies und paläogeographie des oberostalpinen malms.– mitt. geol. ges., 63 (1970), 52–141. ferneck, f.e. (1962): stratigraphie und fazies im gebiet der mittleren saalach und des reiteralm-gebirges: ein beitrag zur deckenfrage in den berchtesgadener alpen.– unpubl. phd thesis, techn. univ. münchen, 107 p. flügel, e. (1964): ein neues vorkommen von plassenkalk (ober-jura) im steirischen salzkammergut, österreich.– n. jb. geol. paläont. abh., 120, 213–232. frisch, w. & gawlick, h.j. (2003): the nappe structure of the central northern calcareous alps and its disintegration during miocene tectonic extrusion – a contribution to understanding the orogenic evolution of the eastern alps.– int. j. earth sci., 92, 712–727. doi: 10.1007/s00531-003-0357-4 gaupp, r.h. (1983): die paläogeographische bedeutung der konglomerate in den losensteiner schichten (alb, nördliche kalkalpen).– zitteliana, 10, 155–171. gawlick, h.j. & frisch, w. (2003): the middle to late jurassic carbonate clastic radiolaritic fl ysch sediments in the northern calcareous alps: sedimentology, basin evolution and tectonics – an overview.– n. jb. geol. paläont. abh., 230, 163–213. gawlick, h.j. & schlagintweit, f. (2006): berriasian drowning of the plassen carbonate platform at the type-locality and its bearing on the early eoalpine orogenic dynamics in the northern calcareous alps (austria).– int. journ. earth sci., 95, 451–462. doi: 10.1007/s00531-005-0048-4 felix schlagintweit: the dasycladalean algae of the plassen carbonate platform (kimmeridgian-early berriasian)... geologia croatica 205 gawlick, h.j. & schlagintweit, f. (2009): revision des tres sensteinkalkes: neuinterpretation der späten ober-jura bis? unterkreide-entwicklung des plattform-becken-überganges der plassenkarbonatplattform (österreich, nördliche kalkalpen).– j. alpine geol., 51, 1–30. gawlick, h.j. & schlagintweit, f. (2010): the drowning sequence of mount bürgl in the salzkammergut area (northern calcareous alps, austria): evidence for a diachronous late jurassic to early cretaceous drowning of the plassen carbonate platform.– austrian j. earth sci., 103, 58–75. gawlick, h.j., frisch, w., vecsei, a., steiger, t. & böhm, f. (1999) : the change from rifting to thrusting in the northern calcareous alps as recorded in jurassic sediments.– geol. rdsch., 87, 644–657. gawlick, h.j., missoni, s., schlagintweit, f., suzuki, h. & frisch, w. (2009): jurassic tectonostratigraphy of the austroalpine domain.– journal of alpine geology, 50, 1–152. gawlick, h.j., missoni, s., schlagintweit, f. & hisashi, s. (2010): tiefwasser beckengenese und initiierung einer karbonatplattform im jura des salzkammergutes (nördliche kalkalpen, österreich).– j. alpine geol., 52, 63–136. gawlick, h.j., schlagintweit, f., ebli, o. & suzuki, h. (2004): die plassen-formation des krahstein (steirisches salzkammergut, österreich) und ihre unterlagerung: neue daten zur fazies, biostratigraphie und sedimentologie.– zbl. geol. paläont. teil 1 2003 3/4, 295–334. gawlick, h.j., schlagintweit, f. & missoni, s. (2005): die barmsteinkalke der typlokalität nordwestlich hallein (hohes tithonium bis tieferes berriasium; salzburger kalkalpen) – sedimentologie, mikrofazies, stratigraphie und mikropaläontologie: neue aspekte zur interpretation der entwicklungsgeschichte der ober-jura-karbonatplattform und der tektonischen interpretation der hallstätter zone von hallein – bad dürrnberg.– n. jb. geol. paläont. mh., 236, 351–421. gawlick, h.j., schlagintweit, f. & missoni, s. (2007): das ober-jura seichtwasser-karbonat-vorkommen der drei brüder am wolfgangsee (salzkammergut, österreich): das westlichste vorkommen der wolfgangsee-karbonatplattform südlich der brunnwinklschwelle am nordrand des tauglboden-beckens.– j. alpine geol. (mitt. ges. geol. bergbaustud. österr.), 48, 83–100. geyer, g. (1884): über jurassische ablagerungen auf dem hochplateau des toten gebirges in der steiermark.– jb. geol. r.a., 34, 335–366. granier, b. (1988) : algues chlorophyceae du jurassique terminal et du crétacé inférieur en alicante.– mediterranea ser. estud. geol., 5 (1986), 5–96. granier, b. (2010): bucurella, a new genus of the tribe thyrsoporelleae (fossil dasycladalean algae).– carnets de géologie / notebooks on geology cg2010_a03. granier, b. & bucur, i.i. (2010): stratigraphic ranges of some tithonian-berriasian benthic foraminifers and dasycladales. re-evaluation of their use in identifying this stage boundary in carbonate platform settings.– in: grosheny, d., granier, b. & sanders, n. (eds.): platform to basin correlations in cretaceous times. abstracts. boletín del instituto de fisiografía y geología, 79–80. granier, b. & deloffre, r. (1993): inventaire critique des algues dasycladales fossils – ii° partie – les algues dasycladales du jurassique et du crétacé.– rev. paléobiol., 12, 19–65. hauer, f., von (1857): ein geologischer schnitt der alpen von passau bis duino.– sitzber. math.-naturwiss. cl. k. akad. wiss., 25/1, 253–348. hofmann, t. (1994): chinianella (?) scheympfl ugi, a new dasyclad alga (green algae) from the tithonian ernstbrunn limestone in lower austria.– beitr. geol., 19, 143–147. husinec, a. & sokač, b. (2006): early cretaceous benthic associations (foraminifera and calcareous algae) of a shallow tropicalwater platform environment (mljet island, southern croatia).– cret. res., 27, 418–441. doi: 10.1016/j.cretres.2005.07.008 jaffrezo, m. & renard, m. (1979): elements en traces de calcaires à dasycladales et charophytes.– bull. cent. rech. explor.-prod. elf-aquitaine mém., 3, 639–649. kügler, u., schlagintweit, f., suzuki, h. & gawlick, h.j. (2003): stratigraphie und fazies des höheren mittelbis ober-jura im bereich des falkensteinzuges am wolfgangsee, salzkammergut (österreich) mit besonderer berücksichtigung der plassen-formation (kimmeridgium).– in: weidinger, j.t., lobitzer, h. & spitzbart, i. (eds.): beiträge zur geologie des salzkammergutes. gmundner geo-stud., 2, 97–106. mandl, g. (1982): jurassische gleittektonik im bereich der hallstätter zone zwischen bad ischl und bad aussee (salzkammergut, österreich).– mitt. ges. geol.-bergbaustud. österr., 28, 55–76. masse, j.-p., bucur, i.i., virgone, a. & dalmasso, h. (1999): nouvelles espèces de dasycladales du crétacé inférieur de provence (s.e. france).– rev. micropaléont., 42/3, 231–243. misik, m. & sykora, m. (1981): der pieninische exotische rücken, rekonstruiert aus geröllen karbonatischer gesteine kretazischer konglomerate der klippenzone und der manín-einheit.– západne karpaty sér. geol., 7, 7–111. missoni, s. & gawlick, h.j. (2011): jurassic mountain building and mesozoic-cenozoic geodynamic evolution of the northern calcareous alps as proven in the berchtesgaden alps (germany).– facies, 57, 137–186. doi: 10.1007/s10347-010-0025-1 missoni, s., schlagintweit, f., suzuki, h. & gawlick, h.j. (2001): die oberjurassische karbonatplattformentwicklung im bereich der berchtesgadener kalkalpen (deutschland) – eine rekonstruktion auf der basis von untersuchungen polymikter brekzienkörper in pelagischen kieselsedimenten (sillenkopf-formation).– zbl. geol. paläont. 2000 heft 1/2, 117–143. mojsisovics, e. (1868): über den malm des salzkammergutes.– verh. geol. r.a., 1868, 124–128. moshammer, b. & lobitzer, h. (2000): weißmetrik und geochemie ausgewählter österreichischer kalksteinund marmor-vorkommen.– mitt. österr. geol. ges., 91, 63–77. peybernès, b. (1979) : les algues du jurassique et du crétacé inférieur des pyrénées franco-espagnoles. interêt biostratigraphiqe et paléoécologique.– bull. centres rech. explor.-prod. elf-aquitaine, 3, 733–741. plöchinger, b. (1964): zum nachweis jurassisch-kretazischer eingleitungen von hallstätter gesteinsmassen beiderseits des salzachquertales (salzburg).– geol. rdsch., 73/1, 293–306. radoićič, r. (1972): contributions to the stratigraphy of the upper cretaceous in western serbia. micropaleontological aspects of the upper cretaceous sedimentary series of skrapez.–ann. géol. pénins. balkan., 37, 89–99. radoićič, r. (2005): new dasycladales and microbiota from the lowermost valanginian of the mirdita zone.– ann. géol. pénins. balk., 66 (2004–2005), 27–53. rasser, m. & fenninger, a. (2002): jurassic / cretaceous dasycladalean algal stratigraphy in the northern calcareous alps: a critical review and a palaeobiogeographic approach using similarity indices.– in: bucur, i.i. & filipescu, s. (eds.): research advances in calcareous algae and microbial carbonates. proc 4th int ifaa reg meet cluj-napoca, 167–190, cluj university press. sanders, d., lukesch, m., rasser, m. & skelton, p. (2007): shell beds of diceratids ahead of a low-energy gravelly beach (tithonian, northern calcareous alps, austria): palaeoecology and taphonomy.– austrian j. earth sci., 100, 186–199. geologia croatica 64/3geologia croatica 206 schlagintweit, f. (1991): neritische oberjuraund unterkreidekalkgerölle aus den losensteiner schichten (alb-cenoman) der typlokalität stiedelsbachgraben (oberösterreich; nördliche kalkalpen).– mitt. ges. geol. bergbaustud. österr., 37, 83–95. schlagintweit, f. (1992): further record of calcareous algae (dasycladaceae, udoteaceae, solenoporaceae) from the upper cretaceous of the northern calcareous alps (gosau formation, branderfl eck formation).– rev. paléobiol., 11, 1–12. schlagintweit, f. (2005): neogyroporella? gawlicki n. sp., a new dasycladale from the upper jurassic-lower cretaceous “lärchberg formation” of the northern calcareous alps.– geol. croat., 58, 1–15. schlagintweit, f. (2008): bioerosional structures and pseudoborings from late jurassic and late cretaceous-paleocene shallowwater carbonates (northern calcareous alps, austria; se france) with special reference to cryptobiotic foraminifera.– facies, 54, 377–402. doi: 10.1007/s10347-008-0137-5. schlagintweit, f. (2010): a false aciculariacean alga and its origin: an example from the upper jurassic of the northern calcareous alps, austria.– facies, 57, 267–273. doi: 10.1007/s10347-010-0242-0 schlagintweit, f. (2011): morphological precisions on chinianella? scheympfl ugi hofmann, 1994, a widespread late jurassic dasycladalean algae of the western tethyan domain.– studias universitatis babes-bolyai, geologia, 56, 3–9. doi: 10.5038/19378602.56.1.1 schlagintweit, f., dieni, i. & radoićič, r. (2009): two lookalike dasycladalean algae: clypeina isabellae masse, bucur, virgone & delmasso, 1999 from the berriasian of sardinia (italy) and clypeina loferensis n. sp. from the upper jurassic of the northern calcareous alps (austria).– ann. géol. penins. balk., 70, 43–59. schlagintweit, f., dragastan, o. & gawlick, h.-j. (2008): halimeda misiki n. sp., a new calcareous alga from the late jurassic of the northern calcareous alps (austria).– n. jb. geol. paläont., 248/2, 171–182. doi: 10.1127/0077-7749/2008/0248-0171 schlagintweit, f. & ebli, o. (1999): new results on stratigraphy, facies and sedimentology of late jurassic to early cretaceous platform carbonates of the austrian salzkammergut (plassen formation, tressenstein limestone).– abh. geol. b.-a., wien, 56/2, 379–418. schlagintweit, f. & ebli, o. (2000): short note on clypeina catinula carozzi, 1956 (dasycladale).– rev. paléobiol., 19, 465–473. schlagintweit, f. & gawlick, h.j. (2007): analysis of late jurassic to early cretaceous algal debris-facies of the plassen carbonate platform in the northern calcareous alps (germany, austria) and in the kurbnesh area of the mirdita zone (albania) – a tool to reconstruct tectonics and paleogeography of eroded platforms.– facies, 53, 209–227. doi: 10.1007/s10347-006-0100-2 schlagintweit, f., gawlick, h.j. & missoni, s. (2006): nachweis einer emersion der trattberg-schwelle im ober-juraklasten spektrum der barmsteinkalke und paläogeographische bedeutung (nördliche kalkalpen, österreich).– in: tessadri wack erle, m. (ed.): pangeo austria, innsbruck university press 2006, 306–307. schlagintweit, f., gawlick, h.j. & lein, r. (2003): die plassen-formation der typlokalität (salzkammergut, österreich) – neue daten zur fazies, sedimentologie und stratigraphie.– mitt. ges. geol. bergbaustud. österr., 46, 1–34. schlagintweit, f., gawlick, h.j. & lein, r. (2005): mikropaläontologie und biostratigraphie der plassen-karbonatplattform der typlokalität (ober-jura bis unter-kreide, salzkammergut, österreich).– j. alpine geol. (mitt. ges. geol. bergbaustud. österr.), 47, 11–102. schmid, d.u. (1996): marine mikrobolithe und mikroinkrustierer aus dem oberjura.– profi l, 9, 101–251. senowbari-daryan, b., bucur, i.i. & abate, b. (1994): upper jurassic calcareous algae from the madonie mountains, sicily.– beitr. paläont., 19, 227–259. sokač, b. (1987): on some controversial dasyclad genera and species and their stratigraphic position in the lower cretaceous deposits of the dinarides.– geol. vjesnik, 40, 9–38. sokač, b. (1996): taxonomic review of some barremian and aptian calcareous algae (dasycladales) from the dinaric and adriatic karst regions of croatia.– geol. croat., 49, 1–79. sotak, j. & misik, m. (1993): jurassic and lower cretaceous dasycladalean algae from the western carpathians.– in: barattolo, f. et al. (eds.): studies on fossil benthic algae. boll. soc. paleont. ital. spec. 1, 383–404. steiger, t. (1981): kalkturbidite im oberjura der nördlichen kalkalpen (barmstein kalke, salzburg, österreich).– facies, 4, 215–348. doi: 10.1007/bf02536589 steiger, t. & wurm, d. (1980): faziesmuster oberjurassischer plattform-karbonate (plassenkalke, nördliche kalkalpen, steirisches salzkammergut, österreich).– facies, 2, 241–284. doi: 10.1007/ bf02536468 tollmann, a. (1965): faziesanalyse der alpidischen serien der ostalpen.– z. dtsch. geol. ges., 116 (1964), 359–389. tollmann, a. (1981): oberjurassische gleittektonik als hauptformungsprozeß der hallstätter region und neue daten zur gesamttektonik der nördlichen kalkalpen in den ostalpen.– mitt. österr. geol. ges., 74/75, 167–195. tollmann, a. (1985): geologie von österreich. wien, franz deuticke, volume 2, 710 p. trauth, f. (1950): die fazielle ausbildung und gliederung des oberjura in den nördlichen ostalpen.– verh. geol. b.a., 1948, 145–218. weynschenk, r. (1950): die jura-mikrofauna und –fl ora des sonnwendgebirges (tirol).– schlern-schriften, universität innsbruck, 83, 1–32. weynschenk, r. (1951): two new foraminifera from the dogger and upper triassic of the sonnwend mountains of tyrol, austria.– journ. paleontol., 25, 793–795. wyssling, g. (1986): der frühkretazische helvetische schelf in vorarlberg und im allgäu – stratigraphie, sedimentologie und paläogeographie.– jb. geol. ba, 129, 161–265. manuscript received april 04, 2011 revised manuscript accepted july 15, 2011 available online october 26, 2011  geologia croatica 65/3 393–410 5 figs. 2 tabs. 2 pls. zagreb 2012 ab stra ct this work is the first attempt to undertake a biostratigraphic study on calcareous nannofossil assemblages of the exposed upper cretaceous to lower eocene rocks at the malaqet and mundassah sections, western flank of the northern oman mountains. the upper cretaceous to lower eocene rocks belong to the simsima formation and the muthaymimah formation. specimens of calcareous nannofossils identified during this study have been ascribed to 67 different species. the cretaceous/palaeocene boundary can be placed in correspondence with the unconformity between the mentioned formations. the presence of a big hiatus in this area is suggested by the absence of the latest maastrichtian micula prinsii nannofossil zone, and the palaeocene np1 and np2 nannofossil zones. in the two study sections, the danian/selandian boundary is placed at the level of the first occurrence (fo) of fasciculithus tympaniformis (base of np5 zone). at jabal mundassah, the selandian/thanetian boundary is positioned at the fo of discoaster mohleri, which is used to define the base of np7/8 zone. unfortunately, a major hiatus is detected at the selandian/thanetian boundary at the jabal malaqet section as indicated by the absence of np6 and np7/8 zones. the paleocene/eocene boundary is placed at the base of subzone np9b at jabal mundassah, whereas at jabal malaqet the paleocene/eocene boundary interval is missing and a major hiatus is testified by the absence of the np9b subzone and np10 zone. keywords: jabals: malaqet and mundassah, calcareous nannofossils, simsima formation, muthaymimah formation, upper cretaceous, paleocene, lower eocene, biostratigraphy, northern oman mountains upper cretaceous to lower eocene calcareous nannofossil biostratigraphy from malaqet and mundassah sections western flank of the northern oman mountains  mahmoud faris1 osman abdelghany2 and mahmoud abu saima2 1 geology department, faculty of science, tanta university, tanta, egypt; (corresponding author: mhmfaris@yahoo.com) 2 geology department, faculty of science, united arab emirates university, al-ain, p.o. box 17551, united arab emirates doi: 104154/gc.2012.29 1. introduction the upper cretaceous – lower eocene rocks are widely exposed in the western foothills of the northern oman mountains (fig. 1). upper cretaceous rocks are the oldest units lying unconformably upon the semail ophiolite and folded, thrusted hawasina and sumeini groups of permian-late cretaceous age (glennie et al., 1974, and wilson, 2000). the stratigraphy and facies of the upper cretaceouseocene neoautochthonous sequence of the northern oman mountains have been discussed in numerous papers, including glennie et al. (1974); hamdan (1990); al sharhan & kendall (1991); anan (1993); noweir & el outefi (1997); noweir et al. (1998); sayed & mersal (1998); boukhary et al. (1999); alsharhan et al. (2000); noweir & abdeen (2000); abd-allah geologia croaticageologia croatica geologia croatica 65/3geologia croatica 394 figure 1: simplified geologic map (modified from abdel-gawad et al., 2010 showing the location of the studied sections. figure 2: field photographs of the study area: 1, 2 – jabal mundassah; 3, 4 – jabal malaqet. faris et al.: upper cretaceous to lower eocene calcareous nannofossil biostratigraphy from malaqet and mundassah sections... geologia croatica 395 figure 3: lithostratigraphic description of jabal malaqet section. geologia croatica 65/3geologia croatica 396 figure 4: lithostratigraphic description of jabal mundassah section. faris et al.: upper cretaceous to lower eocene calcareous nannofossil biostratigraphy from malaqet and mundassah sections... geologia croatica 397 (2001); wilson & taylor (2001); abdelghany (2003); baghdady & abu-zeid (2003); shebl (2004) and abdel gawad et al. (2010). discussion of the calcareous nannofossil biostratigraphy of upper cretaceous to lower eocene rock units (simsima and muthaymimah formations) cropping out at jabals malaqet and mundassah is presented here. in addition, an attempt is made to identify the maastrichtian/danian, danian/selandian, selandian/thanetian and the thanetian/ ypresian boundaries by means of calcareous nannofossil biostratigraphy. 2. materials and methods two sedimentary successions have been measured and sampled at jabals malaqet and mundassah. all together ca. 250 rock samples were collected for this study (figs. 1–4). smear slides for calcareous nannofossil investigation were prepared according to the techniques proposed by bramlette & sullivan (1961) and hay (1964, 1970). the slides were examined using a carl zeiss microscope at 1250x magnification in both plane polarized light and crossed nicols. our data is reported in tables 1 and 2. photomicrographs of some representative taxa are provided in plates 1 and 2. 3. stratigraphic background the post-obduction neoautochthonous upper cretaceouseocene sedimentary succession unconformably overlies upper cretaceous serpentinite, peridotite and pyroxenite of the semail ophiolite. the first marine transgression initiated deposition of shallow marine sediments and fluvial facies inland (qahlah formation) over the eroded knappes of the semail ophiolite (glennie et al., 1974). the qahlah formation is overlain by deposition of shallow-water limestones referred to as the simsima formation. they are exposed at jabals qarn el barr, el faiyah range mountains, el rawdah, malaqet and mundassah. however, farther to the north at jabal qarn el barr, the simsima formation is represented by deep marine deposits of pelagic sediments, based on the evidence of the occurrence of planktonic foraminifera. the simsima formation is unconformably overlain by the muthaymimah formation. 3.1. simsima formation the simsima formation was first described by glennie et al. (1974). since the type section of the simsima formation is no longer accessible, nolan et al. (1990) designated the jabal buhays section, el fayiah range mountains, on the western side of the northern oman mountains (19 km table 1: stratigraphic ranges of calcareous nannofossils of jabal malaqet. paleocene early eocene age danian selandian thanetian ypresian muthaymimah formation 3 4 5 6 15 17 20 24 25 26 29 36 43 47 48 49 54 55 56 57 58 61 sample no. c c c c vr vr vr vr vr vr vr vr vr vr vr vr r vr f r r f abundance m m g g p p m m m p p p p p p p p p m m p m preservation np4 np5 np9a np11 biozones (np) r r r r thoracosphaera operculata f r r f cruciplacolithus primus r r r f cruciplacolithus tenuis* r f f f chiasmolithus danicus* r r r r placozygus sigmoides r r r r neochiastozygus medestus vr vr vr ellipsolithus macellus* f f f f vr vr vr vr vr vr r vr r vr r ericsonia cava vr vr vr vr vr vr r r sphenolithus primus vr vr vr vr vr vr vr vr vr vr vr r vr vr fasciculithus tympaniformis* vr vr vr vr r vr r r r discoaster multiradiatus* vr vr r vr r coccolithus pelagicus vr r vr r discoaster barbadiensis vr r vr r discoaster binodosus vr zygrhablithus bijugatus vr braarudosphaera bigelowii vr tribrachiatus orthostylus* abundance: a= abundant, c= common, f= frequent, r= rare, vr= very rare preservation: g= good, m= moderate, p= poor, *= marker species geologia croatica 65/3geologia croatica 398 ta bl e 2: s tr at ig ra ph ic ra ng es o f c al ca re ou s n an no fo ss ils o f j ab al m un da ss ah . la te c re ta ce ou s pa le oc en e ag e la te m aa st ric ht ia n d an ia n si m si m a m ut ha ym im ah fo rm at io n 2 5 6 7 8 9 11 12 13 14 15 16 17 18 20 21 22 23 24 25 26 27 28 29 29 30 30 31 32 33 34 35 36 37 38 39 sa m pl e no . vr vr vr vr vr r vr vr r vr r r vr vr vr vr r vr r vr r r f f f f f f c c r r f r vr vr ab un da nc e m m m m m m m m m m m m m m m m m m m m m g g m m g g g g g m m g m m m pr es er va tio n m ic ul a m ur us ch ia sm ol ith us d an ic us (n p3 ) cn b io zo ne vr vr vr vr vr vr vr vr vr vr vr vr vr vr vr vr vr vr w at zn au er ia b ar ne sa e vr vr vr vr vr vr vr vr vr vr vr vr vr vr vr vr vr m ic ul a m ur us * vr vr vr vr vr vr vr vr vr vr vr vr vr vr vr vr vr m ic ul a de cu ss at a vr vr vr vr ar kh an ge lsk ie lla cy m bi fo rm is vr cr ib ro sp ha er el la e hr en be rg ii vr m ic ul a co nc av a vr vr lu ci an or ha bd us ca ye ux ii vr st ra dn er ia cr en ul at a vr ei ffe lli th us tu rr isi eff el ii vr vr cr uc ip la co lit hu s p rim us vr r r r r f f f f vr f r f r er ic so ni a ca va vr vr vr vr vr r vr vr vr vr vr vr vr th or ac os ph ae ra o pe rc ul at a r r r vr r r vr vr vr vr vr ch ia sm ol ith us d an ic us * vr r r r vr vr cr uc ip la co lit hu s t en ui s* vr f f f f f f r vr er ic so ni a su bp er tu sa vr r r r vr co cc ol ith us p el ag ic us vr vr vr vr vr vr vr pl ac oz yg us si gm oi de s faris et al.: upper cretaceous to lower eocene calcareous nannofossil biostratigraphy from malaqet and mundassah sections... geologia croatica 399 ta bl e 2: c on tin ue d. pa le oc en e ag e d an ia n se la nd ia n m ut ha ym im ah fo rm at io n 40 41 42 43 44 45 46 47 48 49 50 52 53 54 55 56 57 58 59 60 61 62 63 65 67 69 71 72 73 75 76 78 79 84 91 92 95 99 10 0 10 1 10 3 10 4 10 5 sa m pl e no . f f c f r r c f f f c f r f r vr vr r vr r f c c f f r vr vr vr vr vr vr vr vr r vr r r vr r r f r ab un da nc e m m m m m p m m m g m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m pr es er va tio n n p4 n p5 n p6 cn b io zo ne r r f f f r vr vr vr r f r vr vr vr vr vr vr vr r er ic so ni a ca va vr vr vr r r r r r f f r r vr vr vr vr vr vr r r f r vr vr vr vr vr vr vr vr vr th or ac os ph ae ra o pe rc ul at a vr vr vr vr vr vr vr vr vr vr vr r vr vr vr vr vr r f f f vr vr ch ia sm ol ith us d an ic us * r r c f f c r vr r f r r r er ic so ni a su bp er tu sa vr vr r vr vr vr vr vr vr vr vr vr vr vr vr vr vr r co cc ol ith us p el ag ic us r vr vr vr el lip so lit hu s m ac el lu s* vr vr vr vr vr vr r r vr vr pl ac oz yg us si gm oi de s vr vr r vr vr vr vr r vr cr uc ip la co lit hu s t en ui s* vr vr vr vr vr vr r vr vr n eo ch ia st oz yg us m ed es tu s vr m ar ka liu s i nv er su s f vr r f th or ac os ph ae ra sa xe a vr f vr ch ia sm ol ith us co ns ue tu s vr f vr vr vr vr vr vr vr vr fa sc ic ul ith us ty m pa ni fo rm is* vr f r r vr vr vr vr vr vr vr vr vr r vr r sp he no lit hu s p rim us r vr vr bo m ol ith us e le ga ns vr vr vr fa sc ic ul th us b ill ii vr n eo ch ia st oz yg us im br ie i r fa sc ic ul th us b ob ii vr vr vr vr vr vr vr vr fa sc ic ul ith us u lii vr vr vr fa sc ic ul ith us p ile at us vr vr vr h el io lit hu s k le in pe lli i* fa sc ic ul ith us st on eh en ge i geologia croatica 65/3geologia croatica 400 ta bl e 2: c on tin ue d. la te p al eo ce ne ag e th an et ia n m ut ha ym im ah fo rm at io n 10 6 10 7 10 9 11 0 11 2 11 3 11 4 11 5 11 7 11 8 12 0 12 1 12 2 12 3 12 4 12 5 12 6 12 7 12 8 12 9 13 0 13 1 13 2 13 3 13 4 13 5 13 6 13 7 13 8 13 9 14 0 14 1 14 2 14 3 14 4 14 5 14 6 14 7 14 8 14 9 15 0 15 1 15 2 15 3 15 4 sa m pl e no . c c c c vr r r r r f f f f f f vr vr vr vr r vr f f r r vr f f r r f f c c c r r r c c c f f r c ab un da nc e m m m m m m m m m g m m g g m m m m m m m m m m m m m m m m m m m m m m m m g g g m m m g pr es er va tio n n p7 /8 n p9 a cn b io zo ne vr vr vr vr vr vr vr th or ac os ph ae ra o pe rc ul at a r r r f vr vr r er ic so ni a ca va r r vr f vr vr r vr r vr r r f r r vr vr vr vr vr f r vr vr vr r r vr vr r r r f f vr vr vr r r r vr vr vr r co cc ol ith us p el ag ic us f f f r vr vr vr r r vr vr vr vr vr r r r vr vr vr f f vr vr vr vr r f r r vr vr fa sc ic ul ith us ty m pa ni fo rm is* f f f c vr vr vr r vr r vr vr f r r vr vr r r vr vr vr vr vr r vr vr f f r r vr vr vr f f r f vr f sp he no lit hu s p rim us vr vr vr vr vr vr vr vr vr r vr vr d isc oa st er m oh le ri* vr vr vr bo m bo lit hu s c on ic us vr vr bo m ol ith us e le ga ns vr vr ch ia sm ol ith us d an ic us * vr vr r h el io lit hu s k le in pe lli i* vr vr d isc oa st er oi de s b ra m le tt ei vr fa sc ic ul ith us a la ni i vr vr ch ia sm ol ith us ca lif or ni cu s vr h el io lit hu s c an ta br ia e vr fa sc ic ul ith us cl in at us vr vr vr vr vr ch ia sm ol ith us co ns ue tu s vr vr fa sc ic ul ith us u lii r vr vr vr vr f r vr r r vr vr r r er ic so ni a su bp er tu sa vr vr vr vr vr fa sc ic ul ith us li lli an ae vr vr vr vr vr vr vr vr vr fa sc ic ul th us b ob ii vr vr vr r vr vr vr vr fa sc ic ul th us b ill ii vr vr el lip so lit hu s m ac el lu s* vr r r f vr f vr f f f f r f r f d isc oa st er m ul tir ad ia tu s* vr vr vr r vr vr vr r r d isc oa st er b in od os us vr vr r vr r fa sc ic ul ith us in vo lu tu s vr r vr vr vr fa sc ic ul ith us b ite ct us vr r vr fa sc ic ul ith us sc ha ub i r d isc oa st er fa lc at us vr fa sc ic ul ith us th om as ii vr vr fa sc ic ul ith us to ni i vr vr vr vr fa sc ic ul ith us a ub er ta e r r d isc oa st er le nt ic ul ar is faris et al.: upper cretaceous to lower eocene calcareous nannofossil biostratigraphy from malaqet and mundassah sections... geologia croatica 401 table 2: continued. early eocene age ypresian rus formation 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 172 173 175 176 177 178 181 182 183 184 185 186 187 sample no. f f c f c f r r c c c c f r r f f f vr f r f f c c r c f c abundance m m g m m m m m g g m m m m m m m m m m m m m m m m g m g preservation np9b np10 np11 cn biozone a b vr vr vr vr vr vr vr vr r vr vr vr vr vr r vr vr vr r coccolithus pelagicus vr vr f vr vr r vr r f f f r vr vr fasciculithus tympaniformis* r r r r r f vr r f f f f vr vr r r vr r vr vr r r vr f f vr f sphenolithus primus f r f f f f vr r r f f f vr vr vr vr f r vr f r f r r r vr r vr discoaster multiradiatus* vr vr f r r r vr vr vr r vr vr vr vr vr vr vr vr r discoaster binodosus vr vr vr vr vr vr vr vr vr vr fasciculthus bobii vr vr vr vr vr vr fasciculithus schaubi vr vr vr vr vr vr vr vr discoaster araneus* vr vr vr vr vr vr vr fasciculithus aubertae vr vr vr vr vr vr discoaster falcatus vr vr vr vr fasciculithus alanii vr vr vr vr vr fasciculithus richardii vr vr r vr r r r vr vr vr vr vr vr vr r f sphenolithus moriformis vr vr r vr vr r vr vr vr vr vr vr f vr r vr r r r vr vr vr r ericsonia cava vr vr vr vr fasciculithus bitectus vr vr vr vr vr vr vr vr vr vr vr vr fasciculithus involutus vr vr vr vr vr f vr vr vr vr r vr f f f zygrhablithus bijugatus vr vr vr vr vr vr vr braarudosphaera bigelowii vr fasciculithus lillianae vr vr vr vr vr vr vr vr vr vr vr vr vr vr thoracosphaera operculata vr chiasmolithus consuetus vr vr fasciculithus clinatus vr vr vr vr vr discoaster mahmoudii* vr fasciculithus richardii vr r vr vr vr neochiastozygus junctus vr vr tribrachiatus bramlettei* vr vr f r vr f discoaster barbadiensis r r tribrachiatus digitalis* vr r vr r discoaster diastypus* vr vr vr f tribrachiatus orthostylus* vr pontosphaera multipora vr camplylosphaera dela r ericsonia formosa vr sphenolithus radiatus vr chiasmolithus solitus geologia croatica 65/3geologia croatica 402 plate 1 1 micula murus (martini, 1961) bukry (1973), sample #12, mundassah section 2 thoracosphaera saxea stradner (1961), sample #35, mundassah section 3–4 eiffellithus turriseiffelii (dflandre in deflandre & fert, 1954), sample #17, mundassah section 5 braarudosphaera bigelowii (gran & braarud, 1935), sample #61, malaqet section 6 watznaueria barnesae (black in black & barnes, 1959), sample #25, mundassah section 7–8 arkhangelskiella cymbiformis vekshina (1959), sample #16,mundassah section 9 micula concava (stradner in martini & stradner, 1960), sample #13, mundassah section 10 cribrosphaerella ehrenbergii (arkhangelsky, 1912), sample #13, mundassah section 11 lucianorhabdus cayeuxii dellandre (1959), sample #13, mundassah section 12 ericsonia subpertusa (hay & mohler, 1967), sample #30, mundassah section 13–14 chiasmolithus solitus (bramlette & sullivan, 1961), sample #187, mundassah section 15–16 pontosphaera multipora (kamptner, 1948) roth (1970), sample #187, mundassah section 17 fasciculithus pileatus bukry (1973), sample #75, mundassah section 18 fasciculithus involutus bramlette & sullivan (1961), sample #164, mundassah section 19 sphenolithus radians deflandre in grasse (1952), sample #187, mundassah section 20 zygrhablithus bijugatus (deflandre in deflandre & fert, 1954), sample #168, mundassah section 21–22: sphenolithus primus perch-nielsen (1971), sample #15, malaqet section 23 neochiastozygus junctus (bramlette & sullivan, 1961), sample #181, mundassah section 24 discoaster barbadiensis tan (1927), sample #183, mundassah section *all figures x 1250 faris et al.: upper cretaceous to lower eocene calcareous nannofossil biostratigraphy from malaqet and mundassah sections... geologia croatica 403 plate 2 1 chiasmolithus danicus (brotzen, 1959), sample # 6, jabal malaqet. 2–3 ellipsolithus macellus (bramlette & sullivan, 1961), sample #52, jabal mundassah 4–5 heliolithus kleinpellii sullivan (1964), sample #109, jabal mundassah 6 placozygus sigmoides (bramlette & sullivan, 1961), sample # 6, jabal malaqet 7–8 fasciculithus tympaniformis hay & mohler in hay et al. (1967), sample #24, jabal malaqet 9–10 tribrachiatus orthostylus shamrai (1963), sample #184, jabal mundassah 11–12 discoaster mahmoudii perch-nielsen (198 l), sample #175, jabal mundassah 13–14 tribrachiatus bramlettei (bronnimann & stradner, 1960), sample #173, jabal mundassah 15–16 tribrachiatus digitalis aubry (1996), sample #182, jabal mundassah 17–18 discoaster multiradiatus bramlette & reidel (1954), sample #56. jabal malaqet 19–20 discoaster araneus bukry (1971), sample #158, jabal mundassah *all figures x 1250 geologia croatica 65/3geologia croatica 404 northwest of jabal el rawdah) as an alternative type-section. the simsima formation is unconformably overlain by the muthaymimah formation and overlies the semail ophiolite. at jabal malaqet, it consists of an 8 m-thick dolomitic limestone, with the presence of iron oxide and a rich assemblage of large foraminifera. at jabal mundassah, the simsima formation also consists of a basal dolomitic limestone with iron oxide and rich in large foraminifera, followed by approximately 30 m of greenish-grey to reddish-yellow laminated marls, rich in planktonic foraminifera, and calcareous nannofossils (fig. 5). figure 5: correlation between the identified calcareous nannofossil zones and the studied foraminiferal zones (abdelghany, 2003). faris et al.: upper cretaceous to lower eocene calcareous nannofossil biostratigraphy from malaqet and mundassah sections... geologia croatica 405 3.2. muthaymimah formation this formation was firstly described by nolan et al. (1990) on the northwestern side of sayh muthaymimah, southeast of buraymi, sultanate of oman. the formation unconformably overlies the simsima formation and consists of shale, marl, clay nodules and argillaceous limestone, mudstone, and breccia with conglomerate interbeds including clasts of simsima limestone, reworked rudists, coral fragments, reworked ophiolite and hawasina chert. it is both ferruginous and highly fossiliferous. at jabal malaqet, the lower parts of the muthaymimah formation are composed of greenish grey marl, mudstone and limestone with intraformational conglomerate layers at the base. the middle part of the formation is represented by a 160 m thick sequence of breccia beds with limestone and chert fragments derived from the older rocks (figs. 2, 3). it is topped by marl interlayered with nummulitic, alveolinid limestone of early eocene age. the formation measures about 490 m in thickness. otherwise, at jabal mundassah (figs. 3, 4), the muthaymimah formation unconformably overlies the upper cretaceous simsima formation and consists of interlayered clayrich marl with gypsum veinlets, followed by fossiliferous and argillaceous limestone. its measured thickness is about 340 m. it unconformably overlies the upper cretaceous simsima formation, and is topped by marl interlayered with nummulitic, alveolinid limestone of early eocene age. 4. calcareous nannofossil biostratigraphy calcareous nannofossils are a valuable tool in biostratigraphy, and it was decided to test the use of paleogene calcareous nannofossil zonations (martini, 1971) and successive emendation by romein (1979), and aubry et al. (2000) in the studied area. the present paper describes the distribution of calcareous nannofossil taxa throughout the simsima and muthymimah formations. the identified calcareous nannofossils are generally diverse and abundant in the studied sections, and have enabled subdivision of the studied stratigraphic intervals into nine biozones (tables 1 to 2). the list of the upper cretaceous, paleocene and early eocene calcareous nannofossil taxa is documented in appendix (1), follows that outlined in perch-nielsen (1985a,b). 4.1. upper cretaceous biostratigraphy the upper cretaceous zonal scheme of romein (1979) is adapted here. abbrevations used in the present work are: fo = first occurrence, lo= last occurrence. 4.1.1.the micula murus zone (romein, 1979) the micula murus zone of romein (1979) is defined by the fo of m. murus for the base and the last occurrence of micula murus and other cretaceous taxa and the ab of thoracosphaera and braarudosphaera for the top. age: late maastrichtian occurrence: jabal mundassah section common species: m. murus zone of romein (1979) is equivalent to the lower part of nephrolithus frequens zone (cc 26) of sissingh (1977). at jabal mundassah, this interval is characterized by a well-diversified nannofossil assemblage which include watznaueria barnesiae, micula decussata, arkhangelskiella cymbiformis, cribrosphaerella ehrenbergii, eiffellithus turriseiffelii, lucianorhabdus spp., prediscosphera spp., lithraphidites quadratus and zygodisus spiralis. 4.2. the paleocene and eocene biostratigraphy for the paleocene and eocene, we adopt the biozonation proposed by martini (1971) and emended by aubry et al. (2000). 4.2.1. the chiasmolithus danicus zone (np3) this is defined as the interval from the first occurrence fo of chiasmolithus danicus to the fo of ellipsolithus macellus. age: early palaeocene (latest danian). occurrence: jabal mundassah section. common species: thoracosphaera operculata, and placozygus spp. the following palaeocene nannofossil species first appeared in this zone: cruciplacolithus tenuis, c. primus, coccolithus pelagicus, ericsonia subpertusa and c. danicus. 4.2.2. the ellipsolithus macellus zone (np4) author: martini (1970) the ellipsolithus macellus zone is defined as the interval from the fo of ellipsolithus macellus to the fo of fasciculithus tympaniformis. age: early paleocene (late danian). occurrence: jabals malaqet and mundassah sections common species: the nannofossil taxa present in the np4 zone are those recorded in the np3 zone, plus ellipsolithus macellus. the first taxon ascribable to genus sphenolithus, s. primus, is observed in the upper part of this zone. the first radiation of the fasciculithus genus occurs within np4 zone. 4.2.3. the fasciculithus tympaniformis zone (np5) authors: mohler & hay in hay et al. (1967) the fasciculithus tympaniformis zone is defined as the interval from the fo of fasciculithus tympaniformis to the fo of heliolithus kleinpellii. age: middle palaeocene (selandian) occurrence: jabals: malaqet and mundassah sections common taxa: in the studied sections (mundassah, malaqet), this zone contains a similar assemblage to zone np4 but it is distinguished by the presence of fasciculithus tympaniformis, and bomolithus elegans. a big hiatus is detected in the jabal malaqet section, as shown by the absence of the complete np6 and np7/8 zones. geologia croatica 65/3geologia croatica 406 4.2.4. the heliolithus kleinpellii zone (np6) authors: mohler & hay in hay et al. (1967) the heliolithus kleinpellii zone is defined as the interval from the fo of heliolithus kleinpellii) to the fo of discoaster mohleri. age: middle paleocene (selandian) occurrence: jabal mundassah section common species: this zone includes the same nannofossil species observed in the f. tympaniformis zone plus h. kleinpelli, h. cantabriae and bomolithus conicus. the np6 zone occupies a thin interval at jabal mundassah and is completely absent at jabal malaqet. 4.2.5. the discoaster mohleri zone (np7/8) authors: hay (1964) and mohler in hay et al. (1967) emend romein (1979) since heliolithus riedeli has not been observed in many localities worldwide, romein (1979) emended the definitions of the np7 and np8 zone as originally proposed by martini (1971), defining the discoaster mohleri zone (zone np7/8) as the interval from the fo of d. mohleri to the fo of d. multiradiatus, thus merging together the np7 and np8 zones. we have also combined np7 zone and np8 zone into a np7/8 because h. riedeli is missing in these sections. age: late palaeocene (thanetian) occurrence: jabal mundassah section common species: the np7/8 zone is well represented at jabal mundassah. the np7/8 zone includes the same nannofossil assemblage recorded in the np6 zone, with d. mohleri, d. bramlettei, fasciculithus alanii, f. clinatus, f. lilianae and heliolithus cantabriae. 4.2.6. the discoaster multiradiatus zone (np9) authors: bramlette & sullivan (1961) emend. martini (1971) and bukry & bramlette (1970). the discoaster multiradiatus zone is defined as the interval from the fo of d. multiradiatus to the fo of tribrachiatus bramlettei. age: late paleocene – early eocene occurrence: jabals: malaqet and mundassah sections common species: in the studied sections, the diversity of nannofossil assemblages reaches its maximum within the np9 zone. the discoaster multiradiatus zone is recorded in the jabal malaqet and mundassah sections with variable thicknesses. the second radiation of new fasciculithus species is initiated in zone np9 and includes the fos of f. involutus, f. schaubii, f. thomasii, f. tonii, f. aubertae and f. richardii, which is consistent with previous data (e.g. perchnielsen, 1985; agnini et al., 2007). other taxa first appearing in this zone include: discoaster mahmoudii, d. binodosus, d. falcatus, d. lenticularis, d. araneus d. bar ba diensis, d. diastypus and zygrhablithus bijugatus. aubry et al. (2000) and faris & abu shama (2007) subdivided the d. multiradiatus zone (np9) into two subzones np9a and np9b using the fos of rhamboaster spp. and/ or d. araneus. these biohorizons were proposed by the international subcommission on palaeogene stratigraphy (isps) to approximate the paleocene/eocene (p/e) boundary. at jabal mundassah, the fo of d. areneus has been observed in sample 155 and is used to mark the p/e boundary in this section. at the malaqet section, the top of the np9a subzone cannot be pinpointed due to the absence of rhamboaster taxa and discoaster araneus (markers of the base of the np9b subzone), and the absence of tribrachiatus contortus (the marker of the base of the np10 zone). this suggests the presence of a major hiatus at the p/e transition in this section. 4.2.7. the tribrachiatus contortus zone (np10) authors: hay (1964) and bukry (1973) the tribrachiatus contortus zone is defined as the interval from the fo of tribrachiatus bramlettei to the lo of t. contortus. age: early eocene (ypresian) occurrence: jabal mundassah section common species: the np10 zone has been subdivided into four subzones (np 10a–d) based on the successive biohorizons, the fo of tribrachiatus bramlettei, the fo and lo of t. digitalis, the fo and lo of t. contortus (aubry, 1996). the t.digitalis morphotype shows intermediate morphological features between t. contortus and t. orthostylus and disappears within the lower part of the range of the latter species (raffi et al., 2005). on the other hand, the however, the fo of t. digitalis at odp site 1262 is recorded within the lowermost part of the range of t. contortus (agnini et al., 2007), in agreement with the previous findings of raffi et al. (2005), in palaeoequatorial pacific and north atlantic sections. this implies that the previously proposed subdivision of martini’s (1971) zone np10 (np10a-np10d of aubry, 1999) collapses. consequently the exact duration of subzone np10b (= range of digitalis) remains uncertain. the tribrachiatus digitalis morphotype is often reported from only a few samples. it was recorded in single samples at dsdp site 577 and odp site 1051 (cramer et al., 2003), in two samples from dsdp site 550 (aubry, 1995, aubry et al., 1996), in six samples in the poorly recovered cores 5 and 6 at dsdp hole 117a (aubry, 1995), and in probably only two samples from the proposed p/e gssp section of dababiya in egypt (dupuis et al., 2003). the t. contortus zone (np10) is tentatively recognized at jabal mundassah (t. bramlettei, is observed in samples faris et al.: upper cretaceous to lower eocene calcareous nannofossil biostratigraphy from malaqet and mundassah sections... geologia croatica 407 173 and 184), and t. digitalis is identified from samples 182 and 183 (table 2). it is remarkable that zone np10 is missing at jabal malaqet, suggesting either a small hiatus within the early eocene or a potential sampling gap. 4.2.8. the discoaster binodosus zone (np11) authors: mohler & hay in hay et al. (1967) the discoaster binodosus zone is defined as the interval from the lo of t. contortus and the fo of discoaster lodoensis. age: early eocene (ypresian) occurrence: jabals: malaqet and mundassah sections common species: the lo of t. orthostylus is usually found in the uppermost part of zone np10 in many localities in the world (perch-nielsen, 1985b). perchnielsen, (1985b) mentioned that in case of the absence of t. contortus (its highest occurrence defines the base of the np11 zone) the fo of t. orthostylus can be used to approximate the base of np11 zone. following the reasoning of perch-nielsen (1985b), the fo of t. orthostylus has been utilized here in order to place the base of np11 zone in the studied two sections. besides the nannofossil taxa identified in the np10 zone, other species that first appeared in the np11 zone include t.orthostylus, sphenolithus radians, ericsonia formosa and chiasmolithus solitus. 4.3. stage boundaries the studied upper cretaceous – lower eocene sequence contains a set of biozones covering several stages. the calcareous nannofossils provide a useful global marker for the precise placement of stages and boundaries. in terms of the identified calcareous nannofossils, the cretaceous/palaeogene (k/pg), the danian/selandian, the selandian/thanetian and the paleocene/eocene (p/e) boundaries are briefly discussed below. 4.3.1. the k/pg boundary the global stratotype section and point (gssp) for the k/ pg boundary which has been voted by the international committee on stratigraphy (ics) and ratified by the international union of geological science (iugs) are defined in the el kef section in tunisia. the boundary lies at the base of the boundary clay which consists of a 2.0 mm thick, rust colored ferruginous layer overlain by a 1.0m thick black clayey bed within a monotonous succession of marl. this level coincides with the largest extinction event in planktonic foraminifera, together with an iridium anomaly and an abrupt change in the stable isotope values as well as the carbonate content (arenillas et al., 2002). at the jabal mundassah section, there is a stratigraphic gap around the k/pg boundary interval which includes the uppermost maastrichtian (micula prinsii zone) and the early danian (markalius inversus and cruciplacolithus tenuis zones). cretaceous nannofossils rarely occurred above the k/p boundary in the np3 zone at the jabal mundassah section. in the present study, the authors believe that not all of the cretaceous forms present in the lower danian sediments are due to reworking, but some of them may represent surviving taxa. 4.3.2. the danian/selandian boundary the subdivision of the palaeocene into the danian, selandian and thanetian was proposed by the isps (jenkins & luterbacher, 1992). the global stratotype section and point (gssp) for the base of the selandian stage coincides with; the second evolutionary radiation of the calcareous nannofossil genus fasciculithus, a sharp decrease in the abundance of braarudosphaera and is close to the np4/np5 zonal boundary (bernaola et al., 2009). in the thamad area, east central sinai, egypt, the danian/selandian boundary is tentatively placed at the base of zone np5 (faris & abu shama, 2007). the base of danian stage can be approximated by the base of the np1 zone, while the base of the selandian stage can be approximated at the base of np 5 zone (clemmensen & thomsen, 2005). in the studied two sections, the fo of f. tympaniformis was used to delineate the danian/ selandian boundary which coincides with the np4/np5 zonal boundary. 4.3.3. the selandian/thanetian boundary the base of the thanet formation in kent, england was used to define the selandian/ thanetian boundary. it corresponds to the lower part of the planktonic foraminiferal p4 zone (berggren et al., 1995). the calcareous nannofossil studies showed that the base of the thanetian stage could be referred to the uppermost part of np6 or np6/ np7 (undifferentiated) (berggren et al., 1995). at jabal mundassah, the selandian stage comprises the np5 and np6 zones and the selandian/thanetian boundary is marked at the base of zone np7/8 (d. mohleri zone). at the malaqet section, a major hiatus is suggested at the selandian/thanetian transition because the np6 and np7/8 p.p. zones cannot be recognized. 4.3.4. the p/e boundary the palaeocene/eocene working group placed the gssp for the base of the eocene series in the abandoned quarry of dababiya at the base of the dababiya quarry beds (dqb), luxor, nile valley, egypt and it is defined at the onset of the carbon isotope excursion (cie) (aubry et al., 2007). according to dupuis et al. (2003) the base of the eocene series (base np 9b subzone) can be approximated by the fo of warm-water species (e.g. rhamboaster spineus, r.cuspis, r. intermedia, r. calcitrapa, r. bitrifida and discoaster araneus). at the jabal mundassah section, the fo of discoaster araneus (which defines the base of the np9b subzone,) is used to approximate the base of the eocene. at the malaqet section, the p/e boundary interval is missing and a major hiatus is present as indicated by the absence of the np9b subzone, in addition to the complete absence of the np10 zone (see table 1). geologia croatica 65/3geologia croatica 408 5. summary and conclusions this work presents a calcareous nannofossil biostratigraphic study spanning the maastrichtian – ypresian interval at malaqet and mundassah (southeast of al-ain city, uae). two rock stratigraphic units were recognized in the study area; the simsima formation (late maastrichtian), and the muthayminah formation (palaeocene-early eocene). a stratigraphic gap is located around the k/pg boundary at the mundassah section, where the m. prinsii zone (latest maastrichtian) and np1 to np3 zones (early danian) are absent. the danian/ selandian boundary is positioned where fasciculithus tympaniformis first occurred (at the base of zone np5). the selandian/thanetian boundary is placed at the level of the fo of discoaster mohleri (base of the np7/8 zone), at the jabal mundassah section. a major hiatus is present around the selandian/thanetian boundary at the jabal malaqet section as indicated by the absence of the np6 and np7/8 zones. the palaeocene/eocene boundary is placed at the base of zone np9b (which is defined by the fo of discoaster araneus) at the jabal mundassah section. at the jabal malaqet section the palaeocene/eocene boundary interval is missing and a major hiatus is testified by the absence of the np9 b subzone and np10 zone. acknowledgement the authors wish to thank uae university for providing the necessary facilities to complete this work. we thank mr. hamdi kandil, geology department, uae university for his help in enhancement of the figures and plates of this paper. appendix taxonomy in general follows that outlined in perch-nielsen (1985a and b). upper cretaceous calcareous nannofossil taxa arkhangelskiella cymbiformis vekshina (1959) cribrosphaerella ehrenbergii (arkhangelsky, 1912) deflandre in piveteau (1952) eiffellithus turriseiffelii (deflandre in deflandre and fert, 1954) reinhardt, 1965. lucianorhabdus cayeuxii deflandre (1959) micula concava (stradner in martini & stradner, 1960) verbeek (1976b) micula decussata vekshina (1959) micula murus (martini, 1961) bukry (1973) stradneria crenulata (bramlette & martini, 1964) noel (1970) thoracosphaera operculata bramlette & martini (1964) watznaueria barnesiae (black in black & barnes, 1959) perch-nielsen (1968) paleocene and eocene calcareous nannofossils taxa bomolithus conicus (perch-nielsen, 1971) perchnielsen (1984a) bomolithus elegans roth (1973) braarudosphaera bigelowii (gran & braarud, 1935) deflandre (1947) campylosphaera dela (bramlette & sullivan, 1961) hay & mohler (1967) chiasmolithus californicus (sullivan, 1964) hay & mohler (1967) chiasmolithus consuetus (bramlette & sullivan, 1961) hay & mohler (1967) chiasmolithus danicus (brotzen, 1959) hay & mohler (1967) chiasmolithus solitus (bramlette & sullivan, 1961) locker, 1968 coccolithus pelagicus (wallich, 1877) schiller (1930) cruciplacolithus primus perch-nielsen (1977) cruciplacolithus tennuis (stradner, 1961) hay & mohler in hay et al. (1967) discoaster araneus bukry (1971) discoaster barbadiensis tan (1927) discoaster binodosus martini (1958) discoaster diastypus bramlette & sullivan (1961) discoaster falcatus bramlette & sullivan (1961) discoaster lenticularis bramlette & sullivan (1961) discoaster mahmoudii perch-nielsen (198l) discoaster mohleri bukry & percival (1971) discoaster multiradiatus bramlette & reidel (1954) discoasteroides bramlettei (bukry & sullivan,1971) ellipsolithus macellus (perch-nielsen, 1961) sullivan (1964) ericsonia cava (hay & mohler, 1967) perch ni elsen (1969) ericsonia formosa (kamptner, 1963) haq (1971) ericsonia subpertusa hay & mohler (1967) fasciculithus alanii perch-nielsen (1971) fasciculithus aubertae haq & aubry (1981) fasciculithus billii perch-nielsen (1971) fasciculithus bitectus romein (1979) fasciculithus bobii perch-nielsen (1971) faris et al.: upper cretaceous to lower eocene calcareous nannofossil biostratigraphy from malaqet and mundassah sections... geologia croatica 409 fasciculithus clinatus bukry (1971) fasciculithus involutus bramlette & sullivan (1961) fasciculithus lilianae perch-nielsen (1971) fasciculithus pileatus bukry (1973) fasciculithus richardii perch-nielsen (1971) fasciculithus schaubii hay& mohler (1967) fasciculithus stonehengei haq & aubry, 1981 fasciculithus thomasii perch-nielsen (1971) fasciculithus tonii perch-nielsen (1971) fasciculithus tympaniformis hay & mohler in hay et al. (1967) fasciculithus ulii perch-nielsen (1971) heliolithus cantabriae perch-nielsen (1971) heliolithus kleinpellii sullivan (1964) markalius inversus (deflandre in deflandre & fert, 1954) bramlette & martini (1964) neochiastozygus imbriei haq & lohmann (1976) neochiastozygus junctus (bramlette & sullivan, 1961) perch -nielsen (1971) neochiastozygus modestus perch-nielsen (1971) placozygus sigmoides (bramlette & sullivan, 1961) romein (1979) pontosphaera multipora (kamptner, 1948) roth (1970) sphenolithus moriformis ((bronnimann & stradner, 1960) bramlette & wilcoxon (1967) sphenolithus primus perch-nielsen (19710) sphenolithus radians deflandre in grasse (1952) thoracosphaera operculata bramlette & martini (1964) thoracosphaera saxea stradner (1961) tribrachiatus bramlettei (bronnimann & stradner, 1960) proto decima et al. (1975) tribrachiatus digitalis aubry(1996) tribrachiatus orthostylus shamrai (1963) zygrhablithus bijugatus (deflandre in deflandre & fert, 1954) deflandre (1959). references abd-allah, a.m.a. (2001): folding and faulting of neoautochthonous sequence in the al faiyah fold belt: northern oman mountains, united arab emirates.– annals of the geological survey of egypt, 24, 413–433. abd el-gawad, e.a., abdelghany, o., lotfy, m.a., hashem, w.a. & abu saima, m. (2010): basin analysis of the late cretaceous sediments in united arab emirates.– australian journal of basic and applied sciences, 4/8, 3526–3545. abdelghany, o. (2003): late campanian to maastrichtian foraminifera from the simsima formation, western side of the northern oman mountains.– cretaceous research, 24, 391–405. agnini, c., fornaciari, i.e., raffi, i., rio, d.r.u. & westerhold, t. (2007): high resolution nannofossil biochronology of middle paleocene to early eocene at odp site 1262: implications for calcareous nannoplankton evolution.– marine micropaleontology, 64, 215–248. al sharhan, a.s. & kendall, c.g. (1991): cretaceous chronostratigraphy, unconformities and eustatic sea-level changes in the sediments of the abu dhabi, united arab emirates.– cretaceous research, 12, 379–401. al sharhan, a.s., zico, o.a., shebl, h.t. & wittle, e.g.l. (20000): microfacies and microfabrics of maastrichtian carbonates, northwestern oman mountains, u.a.e.–sepm (society for sedimentary geology), special publication, 69, 129–142. arenillas, i., alegret, l., arz, j.a.l. & rosales-dominguez, c. (2002): cretaceous-tertiary boundary planktonic foraminiferal mass extinction and biochronology at la ceiba and bochil, mexico, and el-kef, tunisia.– in: koeberal, c. & macleod, k.g. (eds.): catastrophic events and mass extinctions: impacts and beyond: boulder, colorado. geological society of america special paper, 356, 253–264. aubry, m.-p. (1995): towards an upper paleocene–lower eocene high resolution stratigraphy based on calcareous nannofossil stratigraphy.– israel journal earth-science,44, 239–253. aubry, m.-p. (1999): late paleocene–early eocene sedimentary history in western cuba: implications for the lptm and for regional tectonic history.– micropaleontology 45, 5–18. aubry, m.-p., berggren, w.a., stott, l. & sinha, a. (1996): the upper paleocene–lower eocene stratigraphic record and the paleocene–eocene boundary carbon isotope excursion: implications for geochronology.– in: knox, r.o. et al. (eds.): correlation of the early paleogene in northwest europe. geol. soc. london, special publication, 101, 353–380. aubry, m.-p., ouda, k., dupuis, c., berggren, w.a., van couvering, j.a. & members of the working group on the paleocene/eocene boundary (2007): the global standard stratotype-section and point (gssp) for the base of the eocene series in the dababiya section (egypt).– episodes, 30, 271–286. aubry, m.-p., requirand, c. & cook, j. (2000): the rhomboaster– tribrachiatus lineage: a remarkable succession of events from 55.5 to 53.2 ma.– gff, 122, 15–18. aubry, m.p. & ouda, k. (2003): introduction to the upper paleocene– lower eocene of the upper nile valley: part i stratigraphy.– micropaleontology, 49 (supplement 1), ii–iv. baghdady, a.r. & abu-zeid, m.m. (2002): petrography, facies and framework of sedimentation of the upper cretaceous-lower tertiary sediments in jabal malaqet, west of the northern oman mountains, united arab emirates, middle east research center, ain shams university.– earth sciences series, 16, 1–15. berggren, w.a., kent, d.v., swisher, c.c.i. & aubry, m.-p. (1995): a revised cenozoic geochronology and chronostratigraphy.– in: hardenbol, j. (ed.): geochronology, time scales and global stratigraphic correlation, society of economic paleontologists and mineralogists, special publication, 54, 129–212. bernaola, g., martín-rubio, m. & baceta, j.i. (2009): new high resolution calcareous nannofossil analysis across the danianselandian transition at the zumaia section: comparisons with south tethys and danish sections.– geologica acta, 7/1–2, 79–92. boukhary, m.a., carter, b.d., al sharhan, a.s. & aly, m.f. (1999): maastrichtian echinoids from the simsima formation, northwestern oman mountains, uae: a systematic view and ecological implications.– revue de paléobiologie, genéve, 18, 577–595. geologia croatica 65/3geologia croatica 410 bramlette, m.n. & sullvan, f.r. (1961): coccolithophorids and related nannoplankton of the early tertiary in california.– micropaleontology, 7, 129–188. bukry, d. (1971): cenozoic calcareous nannofossils from the pacific ocean. transactions of the san diego society natural history, 16, 303–327. bukry, d. (1973a): coccoliths stratigraphy, leg 10-deep sea drilling project. initial reports of the deep sea drilling project, 10, 385–604. washington, dc: us government printing office. bukry, d. (1973b): low latitude coccoliths biostratigraphic zonation. initial reports of the deep sea drilling project, 15, 685–703.washington, dc: us government printing office. dupuis, ch., aubry, m-p., seurbaut t.e., berggren, w., ouda, kh., magioncalda, r., cramer, b.s., kent, d.v., sperjer, r.p. & heilmann-clausen, c. (2003): the dababiya quarry section: lithostratigraphy, geochemistry and paleontology.– micropaleontology, 49 (supplement 1), 41–59. glennie, k.w., boeuf, m.g.a., hughes–clarke, m.w., moody-stuart, m., pillaar, w.f.h. & reinhardt, b.m. (1974): geology of the oman mountains-verhandelingen van ket koninklijk, nederlands geologisch-minjbouwkundig genootschap. (transactions of the royal dutch geological and mineralogical society), 31, 423 p. faris, m. & abu shama. a.m. (2007): nannofossil biostratigraphy of the paleocene–eocene succession in the thamad area, east central sinai, egypt.– micropaleontology, 1–2, 127–144. hamdan, a.a. (1990): maastrichtian globotruncanids from the western front of the northern oman mountains: implications for the age of post-orogenic strata.– journal of faculty of science, united arab emirates university, 2, 53–66. hay, w.w. (1964): the use of the electron microscope in study of fossils.– annual reports smithsonian institute, 1963, 409–415. hay, w.w. (1970): calcareous nannofossils from cores recovered on leg 4.– initial. reports deep sea drilling project, washington, 4, 455–502. hay, w.w., mohler, h.p., roth, p.h., schmidt, r.r & boudreaux, j.e. (1967): calcareous nannoplankton zonation of the cenozoic of the coast and caribbean-antillean area and transoceanic correlation.– trans. gulf coast. association geology society, 17, 28–80. jenkins, d.g. & luterbacher, h.p. (1992): paleogene stages and their boundaries.– newsletter journal geology paleontology, abhandlungen, 186, 1–5. martini, e. (1970): standard paleogene calcareous nannoplankton zonation.– nature, 226, 560–561. martini, e. (1971): standard tertiary and quaternary calcareous nannoplankton zonation.– proceeding of second planktonic conference. rome, 1970, 2, 739–77. nolan, s.c., skelton, p.w., clissold, b.p & smewing, j.d. (1990): maastrichtian to early tertiary stratigraphy and palaeogeography of the central and northern oman mountains.– in: robertson, a.h.f., searle, m.p. & ries, a.c. (eds.): the geology and tectonics of the oman region. geological society of london, special publication, 49, 495–519. noweir, m.a. & eloutefi, n.s. (1997): the structure and stratigraphy of jabal malaqet-jabal mundassa area, southeast al-ain, northern oman mountains, united arab emirates.– neues jahrbuch für geologie und paläontologie, abhandlungen, 204, 263–284. noweir, m.a., alsharhan, a.s. & boukhary, m.a. (1998): structural setting and stratigraphic evolution of the northwestern oman mountain front, united arab emirates.– geoarabia, 3, 387–398. noweir, m.a., & abdeen, m.m. (2000): structural evolution of jabal rawdah area, hatta zone, northwestern oman mountains front.– egyptian journal of geology, 44, 219–235. perch-nielsen, k. (1985a): mesozoic calcareous nannofossils.– in: bollii, h.m., saunders, j.b & perch-nielsen, k. (eds.): plankton stratigraphy. cambridge university press, 329–426. perch-nielsen, k. (1985b): cenozoic calcareous nannofossils.– in: bolli, h.m., saunders, j.b. & perch-nielsen, k. (eds.): plankton stratigraphy. cambridge university press, 427–554. raffi, i., backman, j. & palike, h. (2005): changes in calcareous nannofossil assemblages across the paleocene/eocene transition from the paleo-equatorial pacific ocean.– palaeogeogr., palaeoclimat., palaeoecol., 226, 93–126. romein, a.j.t. (1979): lineages in early paleogene calcareous nannoplankton.– utrecht. micropaleontology bulletin, 22, 1–231. sayed, m.g. & mersal, m.a. (1998): surface geology of jebel rawdah, oman mountains.– geoarabia, 3, 401–414. sissingh, w. (1977): biostratigraphy of cretaceous calcareous nannoplankton.– geologie mijnbouw, 56, 37–65. wilson, h.h. (2000): the age of the hawasina and other problems of oman mountain geology.– journal of petroleum geology, 23, 345–362. worsley, t. & martini, e. (1970): late maastrichtian nannoplankton provinces.– nature, 225, 1242–1243. worsley, t. (1974): the cretaceous/tertiary boundary event in the ocean.– in: hay, w. w. (ed.): studies in paleoceanography. sepm, special. publication, 20, 94–125. manuscript received august 30, 2011 revised manuscript accepted june 18, 2012 available online october 30, 2012 geologia croaticageologia croatica first record of dicrostonyx (rodentia, mammalia) in the late pleistocene/?holocene sediments of croatia  jadranka mauch lenardić institute for quaternary palaeontology and geology, croatian academy of sciences and arts, ante kovačića 5/ii, hr–10000 zagreb, croatia; (jml@hazu.hr) doi: 10.4154/gc.2013.15 ab stra ct the fossil remains of lemmings (dicrostonyx sp.) have been discovered for the first time in croatia. the small sample of 11 teeth (m1-3 and m1) originate from the late pleistocene/?holocene sediments from the romualdova pećina site (western istria). the resemblance has been observed in morphological data, while some metrical parameters differ slightly in comparison to the findings from some other european localities, for example from poland, austria and france. the mean length value of m1s from the croatian sample is higher than the austrian (nixloch and merkenstein caves), and french (bois roche site) ones, while it is the same for similar specimens from the polish late glacial, but smaller than the polish holocene findings, respectively. the differences in a/l and c/w1 indices have also been observed between samples from the romualdova pećina and polish samples of late glacial and holocene age. as a good indicator of a cold and dry climate, the lemmings from the romualdova pećina give support to the conclusion that this part of europe was a refugial region for this and some other small mammal species during the expansions of the ice cover, and reflect quaternary environmental fluctuations, which were frequent and pronounced at the end of this period. keywords: lemming, dicrostonyx, teeth, morphometric analyses, late pleistocene, romualdova pećina, cave, croatia tocene sediments of the romualdova pećina (romualdo’s or lomardo’s cave, in further text romualdova) locality for the first time. the cave is situated on the southern side of the limski (lim) channel near rovinj in western istria (fig. 1), and has been an interesting palaeontological site since the1960s (malez, 1962, 1968, 1978; komšo, 2011). the cave is formed in the upper jurassic limestones, with the entrance at 120 m a. s. l. it is more than 100 m long, and has the shape of underground corridor which is in some places widened into elongated halls (malez, 1962). during field work in 1961, 1962, and 1973, when malez and his team made probe excavations (fig. 2a, b), very abundant fossil material was collected, in which bear (ursus spelaeus and u. arctos) remains were the most numerous, in addition to other taxa listed in figure 2c (after malez’s original deter1. introduction in many areas of the european continent, lemmings (dicrostonyx sp.), as extremely boreal taxa, had disappeared during the last interglacial (riss-würm) period, and in two waves recolonized central and southern europe from the scandinavian region. the first recolonization occured around 40 ka bp, when they reached the alps, carpathians and caucasus mts., while during the second widening of their areas (cca. 20 ka bp), lemmings migrated farther south, in the carpathian basin and southern parts of western europe, respectively (kordos, 1990). during these areal expansions, dicrostonyx also inhabited the region of present day western croatia. results of morphometric analyses of dicrostonyx teeth are presented here. this taxon is determined in the late pleisgeologia croatica 66/3 183–189 3 figs. 2 tabs. zagreb 2013 geologia croatica 66/3geologia croatica 184 mination; malez, 1968). the results of geometric-morphometric analyses of the romualdova bear molars were presented by seetah et al. (2012), where the authors quoted the similarities/differences of bear populations (beside romualdova, the vindija sample has also been investigated) through time and space. detailed revision of the macrofaunal remains is now in progress (miracle et al., in preparation). molars have been separated recently from the small mammal sample and prepared for preliminary analyses by the present author. in this material, the arvicolines prevail, among which voles are the most abundant: arvicola amphibius (=terrestris), myodes (=clethrionomys) glareolus, microtus ex gr. arvalis/agrestis, m. ex gr. subterraneus/multiplex, m.oeconomus, and chionomys nivalis, but other „micromammals“ such as chiroptera and eulipotyphla (=insectivora; genera erinaceus and talpa, fig. 2c) are also represented. as previously mentioned, one of the most interesting discoveries is lemming teeth (dicrostonyx sp.) recorded for the first time from the late pleistocene and perhaps holocene sediments of croatia. in 2007 and 2008, komšo and his team started systematic excavations in the cave (komšo, 2011), and abundant fossil material, collected during these field-campaigns, still waits to be palaeontologically analysed. the lemmings are small arvicoline rodents represented by 12 living species, adapted to cold and dry habitats, having a holarctic distribution today. recent dna techiques and analyses allow different phylogenetic studies on the contemporary lemming populations (e. g. fedorov, 1999; prost et al., 2010; and references therein), that provide new data on the evolutionary rates and phylogenetic relationships of this taxa. the results of mtdna analyses for the populations from the canadian arctic, greenland and eastern beringia have been presented by fedorov & stenseth (2002). the authors argued about the division of different phylogroups (canadian arctic and eastern beringia), and gave the possible time of their divergence at 115 – 10 ka. the hypothesis of ice-free areas during the last glaciation, beside the data of the dicrostonyx findings, is also supported by the fossil specimens of other good indicators of the tundra environments such as saiga (saiga tatarica) and muskoxen (ovibos moschatus; fedorov & stenseth, 2002). the climatic changes at the end of the pleistocene and beginning of holocene also favoured possible habitat changes, which had a direct influence on the distribution and hence on the evolutionary rates in many small mammal taxa, including lemmings. during the pleistocene, especially the late pleistocene, alternation of glacial and interglacial periods resulted with restricted areas of the particular species into refugial figure 1: geographical location of romualdova pećina (western istria) ; internet source: http://www.maps-for-free.com/ jadranka mauch lenardić: first record of dicrostonyx (rodentia, mammalia) in the late pleistocene/?holocene sediments of croatia geologia croatica 185 ones (fedorov & stenseth, 2002). the balkan peninsula is one of the regions of interest for such research (miracle et al., 2010), while migrations of various large and small mammals were defined by the particular geographic position of this part of europe. in his work malez (1986, p. 106) wrote that the most southern locality of dicrostonyx torquatus (arctic or collared lemming) on the territory of the former yugoslavia was babja jama cave near dob at domžale in slovenia (46°03′ n and 14°30′ e). the new discoveries from the croatian romualdova site (45° 7’ 44’’ n and 13°14’ 17’’ e) move this line farther south. the species of the genus dicrostonyx are not the members of the present day fauna of croatia. 2. geological settings malez (1962, 1968, 1978) provided sedimentary and stratigraphic sequences for romualdova (fig. 2), and wrote that fossil remains, including abundant small mammal findings, appeared at layer c in the test-pits made in 1961 and 1962. this layer was most probably sedimented during the würm iii stadial (malez, 1968). furthermore, beside animal remains, stone artefacts, traces of hearths, one human tooth has also been discovered proving the presence of palaeolithic men in the cave (malez, 1968, 1978). the most complex profile of the quaternary layers was discovered in test-pit i (fig. 2). after recent investigations conducted by komšo (2011), and palaeontological analyses in progress, a more precise stratigraphic position of the particular layers will be soon defined. 3. material and methods a small sample of 153 upper and lower arvicoline teeth, separated from other faunal remains which comprise several hundreds of specimens, has been morphometrically analysed. in this collection 11 molars (mainly m1 3, and m1; fig. 3b, c) belong to the genus dicrostonyx. unfortunatelly we do not know the exact stratigraphic position of these fossil remains, and worse still, it is not known from which excavation campaign year they come from. therefore, it is assumed that they belong to the faunal sample from layer c, not only because the majority of the specimens which are stored at the institute’s collections were found in the 1960’s, but also because malez (1978) emphasized that this is the pleistocene layer with abundant fossil findings. furthermore, figure 2: romualdova pećina: a – ground -plan; b – profile; c – stratigraphic profile/ layers with determined fauna. legend: layer a – dark reddish-brown compact clay with small limestone particles, layer b – dark yellow-brown compact clay, layer c – dark brown clay with limestone debris, human traces, and abundant fossil remains, layer d – yellow-reddish fat clay with out limestone debris, layer e – brownish-yellow fine-grained sand with inclusions of reddish clay, layer f – sinter deposit, jl –jurassic limestone (after: malez, 1968). geologia croatica 66/3geologia croatica 186 all collection/inventory numbers contain only locality abbreviations and the ordinal number. taxonomic determinations, molar terminology and metrical methods were used after rabeder (1981), nadachowski (1982) and nagel (1992). measurements: the overall tooth length (l), the length of the anteroconid complex (a), width of the posterior lobus (w), c (distance between lra5 and bra5 inside the enamel wall), w1 (width of anterior part between lsa6 and bsa5) have been measured (fig. 3a), and a/l and c/w1 (ratios were multiplied by 100) indices were calculated (according to nadachowski, 1982). all measurements are in milimetres (mm). morphotypes: morphotypes of m1 have been determined and named after nadachowski (1982, p. 26–27) for the species dicrostonyx gulielmi. the fossil material is stored at the institute for quaternary palaeontology and geology of the croatian academy of sciences and arts in zagreb. abbreviations: used abbreviations are: sin. (sinister = left), dext. (dexter = right), m1, m2, m3 (first, second, third lower molar), m1 (first upper molar), bsa5 (fifth buccal salient angle), lsa6 (sixth lingual salient angle), bra5 (fifth buccal reentrant angle), lra5 (fifth lingual re-entrant angle), t5, t7 (fifth, seventh triangle), luv-side (anterior side of a salient angle), lee-side (posterior side of a salient angle), ka (thousands of years), n (number of specimens), min. (minimum value), max. (maximum value), χ (mean value), rp (romualdova pećina). figure 3: molars of dicrostonyx sp. from the romualdova pećina late pleistocene layers: a – measurement points on the first lower molar (not to scale; drawing partly after: nadachowski, 1982, fig. 2/3); b – mandible with m1 and m2 dext. (collection number: rp/21); c – first upper right molar (m1 dext.; collection number: rp/23). table 1: metrical values (l, a, w, c, w1, a/l, c/w1) for the dicrostonyx sp. molars from romualdova pećina, late glacial and holocene polish samples of d. gulielmi (nadachowski, 1982), and late pleistocene d. torquatus sample from bois roche site in france (sesé & villa, 2008). for abbreviations see the text. measurements and indices (m1) romualdova pećina dicrostonyx sp. poland (holocene) d. gulielmi poland (late glacial) d. gulielmi bois roche, france (late pleistocene) d. torquatus n min.-max. (c) n min.-max. (c) n min.-max. (c) n min.-max. (c) l 5 3.37–3.91 (3.63) 10 3.76–4.06 (3.89) 9 3.43–3.81 (3.63) 7 3.17–3.83 (3.55) a 5 1.97–2.4 (2.17) – – – – – – w 4 1.24–1.42 (1.31) – – – – 7 1.18–1.52 (1.34) c 5 0.19–0.25 (0.22) – – – – – – w1 3 0.95–1.07 (0.99) – – – – – – a/l 5 57.43–62.31 (59.75) 10 55–61 (58) 9 56–61 (58) – – c/w1 3 20–23.36 (21.4) 10 10–30 (23) 9 10–36 (21) – – 4. results order rodentia bowdich, 1821 superfamily muroidea, illiger, 1811 family cricetidae fischer von waldheim, 1817 subfamily arvicolinae gray, 1821 tribe dicrostonychini kretzoi, 1955 genus dicrostonyx gloger, 1841 dicrostonyx sp. (figs. 3a, b, c) material: 11 molars (3 m1 sin.; collection numbers: rp/ 118, 124 and 125), 2 m1 dext. (collection numbers: rp/21 jadranka mauch lenardić: first record of dicrostonyx (rodentia, mammalia) in the late pleistocene/?holocene sediments of croatia geologia croatica 187 janian & koenigswald (1977), and from the aforementioned nixloch cave, a smaller sample of this genus has also been morphometrically analysed (nagel, 1992). in the same article nagel gave the data (so called morphodynamic index) for other austrian sites: kemathenhöhle (30 ka bp), geiβenklösterle (31 ka bp) and kleine scheuer (13.25 ka bp). the latter author analysed the d. gulielmi findings (nagel, 1997) from the merkenstein cave (lower austria) as well, quoting the possibility that the findings belong to the subspecies d. gulielmi gulielmi. the length of m1s from this site shows that they are somewhat smaller than those from nixloch (tab. 2). the age of the merkenstein locality is the same as for nixloch, or even younger. the romualdova teeth show greater length values for the first upper and first lower molars than the aforementioned austrian ones. from the würmian/late glacial faunal list of the knochenhöhle site near kapellen in southeastern austria (~14 – 10 ka bp; fladerer, 2000) dicrostonyx (i. e. d. torquatus f. gulielmi) is also known. after nadachowski (1982) there is a great morphological variability on m1s (in species d. gulielmi), from more primitive morphotypes (e. g. a) with less in number and more confluent triangles to progressive types (g, h, i) with less confluent and up to eight, even nine triangles. other parts of m1s also show some variations, such as connections between two triangles etc. in the croatian sample, variations of the anteroconid complex have not been observed, due to the low number of discovered m1s, and all teeth have eight closed triangles (not confluent). nadachowski (1982, p. 31) discovered decreasing length values of m1s (for the species d. gulielmi, from the lower to upper pleniglacial, and to the late glacial, respectively). in the samples from the holocene (e. g. niedostepna, tunel wielki, ciasna, etc.) the m1 length increases again. furthermore, in the polish sample a/l indices fluctuate between 56 and 58 (original values are 0.56 and 0.58, because they were not multiplied by 100; author’s remark), and significant differences occur between upper pleniglacial and holocene. c/w1 (nadachowski originally signed this ratio as c3/w3; author’s remark) the coefficient also differs statistically (idem, p. 33). the romualdova sample shows the highest a/l values, while the c/w1 index is the same as in the late glacial polish sample (tab. 1). furthermore, dicrostonyx molar length from romualdova has a higher mean value in comparison to the early late pleistocene d. torquatus sample from bois roche (france; sesé & villa, 2008), while for the width it is just the opposite (tab. 1). the record of d. torquatus from hungary (e. g. in jankovich cave, western hungary; jánossy, 1986) is of late glacial age, while it lacks in holocene layers completely. the same author gives detailed faunal lists for other hungarian late pleistocene localities (e. g. pilisszántó /10 km nne from budapest/, remete cave /nw from budapest/, bivak cave /w hungary/, tokod-nagyberek /w from tokod village/, gencsapáti /n from szombathely/, süttő locality no. 6 /~120 km nw from budapest/), where the lemmings were present in different stages and substages. no morphometric data are avaliable in the work of jánossy (1986). the table 2: minimum, maximum and mean values for m1-3 and m1 length of dicrostonyx sp. from romualdova pećina in comparison to the austrian samples (nagel, 1992, 1997). locality length (l) n min.-max. c m1 romualdova pećina 5 3.37–3.91 3.63 nixloch cave 10 3.17–3.73 3.5 merkenstein cave 50 2.25–3.63 3.15 m2 romualdova pećina 4 1.71–1.93 1.81 nixloch cave 23 1.6–2 1.8 m3 romualdova pećina 1 1.92 nixloch cave 11 1.45–2.32 1.71 m1 romualdova pećina 2 2.64–2.67 2.66 nixloch cave 16 2.2–2.78 2.42 merkenstein cave 50 2.03–2.65 2.42 and 22), 3 m2 sin. (collection numbers: rp/118, 124 and 125), 1 m3 sin. (collection number: rp/125), 1 m1 sin., and 1 m1 dext. (part of the skull; collection number: rp/23). description: the molars of dicrostonyx are rootless, without cement, with leptoknem enamel band (luv-side /concave/ is thicker than the lee-side /convex/; see the abbreviations) which is on all anticlines and apexes discontinuous (so called enamel-free areas; fig. 3). the first lower molars (m1) from the croatian sample consists of posterior lobus, eight triangles and anterior cap. on the basis of number and shape of the anteroconid complex agadjanian (1976) proposed four morphotypes (i – iv) for the known dicrostonyx species, which were also presented in the austrian locality nixloch (cave near losenstein-ternberg in upper austria; age: 18.310 ± 580 y bp /14c/; nagel, 1992). in the small sample of five m1s from romualdova the morphotypes have been determined after nadachowski (1982; for the species d. gulielmi). significant variations of the anteroconid complex could not be observed, and all five molars have been determined as pertaining to the morphotype e. the results of the metrical analyses are presented in tables 1 and 2. 5. discussion the dentitions of lemmings show great individual variations (especially on m1s and m3s) on which basis some authors differentiated two species (dicrostonyx gulielmi and d. henseli; hinton, 1910, 1926; cited in: nadachowski, 1982). jánossy (1954) wrote that these two species represent only variations of the species d. torquatus. the evolution of the upper teeth of dicrostonyx from the middle pleistocene to recent was presented by agadgeologia croatica 66/3geologia croatica 188 southernmost locality with lemming remains is near veszprem (about 47° n). guilday (1963) wrote about two species of collared lemmings from the palearctic pleistocene sites, and as the common eurasian fossils, he stressed d. gulielmi (localities: hutton cave, somersetshire, england) as the late pleistocene form of the recent d. torquatus. the same author also mentioned some other old world pleistocene dicrostonyx sites in england, ireland, france, germany, poland, and former czechoslovakia. as previously mentioned, the lemmings had a wide distribution in eurasia during the late pleistocene. the southernmost localities have been discovered in the southwestern part of france, switzerland, hungary and ukraine (jánossy, 1954, villa et al., 2010), and on the north american continent these animals were distributed from alaska to the great lakes (guilday, 1963; repenning et al., 1964, cited from: nadachowski, 1982). on the north american continent, the most southern localities have been recorded in pennsylvania (from ~40° to ~42° n). contemporaneous areas of the lemmings are in the arctic and sub-arctic tundra and forest-tundra in the palearctic (circumpolar), from the white sea, western russia, to the chukotski peninsula, north-east siberia, and kamchatka; including novaya zemlya and the new siberian islands, arctic ocean (wilson & reeder, 2005), but excluding wrangel island (gromov & erbaeva, 1995; pavlinov et al., 2002). tsytsulina et al. (2008) quoted the fact that once it was believed that dicrostonyx torquatus „encompass most or all new world populations, but karyotypic and breeding evidence supports the strict application of d. torquatus for only eurasian populations“ (see also: wilson & reeder, 2005, and references therein). the habitat that dicrostonyx prefers is dry and stony tundra. it is simpatrical with another lemming vole, lemmus, which occupies the same ecological niches. the impact of the herbivorous mammals, including dicrostonyx, on the arctic vegetation as an important lemmingplant interaction was emphasized by oksanen et al. (2008). the lemmings feed on grasses, sedges and other green vegetation in summer, and twigs of willow, aspen and birches in winter, as mentioned for one representative of the genus, dicrostonyx groenlandicus (so called northern collared lemming) which lives in the tundra regions of northern canada, alaska and greenland. the most common lemming predators are snowy owls (bubo scandiacus), gulls, wolverines, the arctic foxes and the polar bears (http://en.wikipedia.org/wiki/northern_collared_lemming). further detailed studies of the faunal remains from ro­ mualdova will provide the answers as to which layers/age the dicrostonyx discoveries on this site originate, and the specific determinations will be possible on the larger sample as the result of the systematic excavations which have been performed in previous years. furthermore, it will be determined whether the romualdova lemmings are more similar to the representatives of the recent species d. torquatus, or more probably, that they belong to d. gulielmi. acknowledgement the author is grateful to dr. gloria cuenca bescós and an anonymous reviewer for their valuable comments and help improving the earlier draft of the manuscript. this study was part of the institute’s projects by the ministry of science, education and sports of the republic of croatia, project 101-2690680-2270 „correlation of the palaeolithic, mesolithic and neolithic of the continental and coastal croatia“ (from 2007 till 2013). references agadjanian, a. (1976): die entwicklung der lemminge der zentralen und östlichen paläoarktis im pleistozän.– mitteilungen der bayerischen staatssammlung für paläontologie und historischen geologie, 15–16, 53–64, münchen. agadjanian, a. & koenigswald, w.v. (1977): merkmalsverschiebung an den oberen molaren von dicrostonyx (rodentia, mammalia) im jungtertiär.– neues jahrbuch für geologie und paläontologie/abhandlungen, 153, 34–49, stuttgart. fedorov, v.b. (1999): contrasting mitochondrial dna diversity estimates in two sympatric genera of arctic lemmings (dicrostonyx: lemmus) indicate different responses to quaternary environmental fluctuations.– proceedings of the royal society, b, 266, 621–626, london. fedorov, v.b. & stenseth, n. chr. (2002): multiple glacial refugia in the north american arctic: inference from phylogeography of the collared lemming (dicrostonyx groenlandicus).– proceedings of the royal society london, ser. b, 269, 2071–2077, london. fladerer, f.a. (2000): late quaternary vertebrate taphocoenoses from cave deposits in southeastern austria: responses in a periglacial setting.– in: hart, m.b. (ed.): climates: past and present. geological society, special publications, london, 181, 199–213. gromov, i.m. & erbaeva, m.a. (1995): the mammals of russia and adjacent territories. lagomorphs and rodents.– zoologicheskii institut ran, sankt peterburg, 522 p. [in russian] guilday, j.e. (1963): pleistocene zoogeography of the lemming, dicrostonyx.– evolution, 17, 194–197. jánossy, d. (1954): fossile microtinae aus dem karpathenbecken. i. lemminge.– annales historico-naturales musei nationalis hungarici, nov. ser., 5, 39–48, budapest. jánossy, d. (1986): pleistocene vertebrate faunas of hungary.– akadémiai kiadó, budapest, 208 p. komšo, d. (2011): romualdova pećina/the romuald's cave.– in: mihe lić, s. (ed.): arheologija i turizam u hrvatskoj/archaeology and tourism in croatia, arheološki muzej u zagrebu, zagreb, 356–361 [in croatian and english]. kordos, l. (1990): the evolution of upper pleistocene voles in central europe.– in: fejfar, o. & heinrich, w.-d. (eds.): international symposium evolution, phylogeny and biostratigraphy of arvicolids (rodentia, mammalia), rohanov (czechoslovakia) may1987, 275–284, praha. malez, m. (1962): romualdo cave – a new significant pleistocene site in istria.– bulletin scientifique, 7, 6, 159–160, zagreb. malez, m. (1968): tragovi paleolita u romualdovoj pećini kod rovinja u istri [paläolitische spuren in der romualdohöhle bei rovinj in istrien].– arheološki radovi i rasprave jazu, 6, 7–26, zagreb [in croatian with german summary]. malez, m. (1978): paleontološka i kvartargeološka istraživanja u 1973. godini [paleontological and geological researches of quaternary in the year 1973].– ljetopis jugoslavenske akademije znanosti i umjetnosti, 78, 559–572, zagreb [in croatian]. jadranka mauch lenardić: first record of dicrostonyx (rodentia, mammalia) in the late pleistocene/?holocene sediments of croatia geologia croatica 189 malez, m. (1986): die quartären vertebraten-faunen in der sfr jugoslawien.– quartärpaläontologie, 6, 101–117, berlin. miracle, p.t., mauch lenardić, j. & brajković, d. (2010): last glacial climates, ‘‘refugia’’, and faunal change in southeastern europe: mammalian assemblages from veternica, velika pe ćina, and vindija caves (croatia).– quaternary international, 212, 137–148. doi:10.1016/j.quaint.2009.06.003 nadachowski, a. (1982): late quaternary rodents of poland with special reference to morphotype dentition analysis of voles.– polska akademia nauk, zakład zoologii systematycznej i doświadczal nej, państwowe wydawnictwo naukowe – oddział w krakowie, 109 p. nagel, d. (1992): die arvicoliden (rodentia, mammalia) aus dem nixloch bei losenstein-ternberg (o.ö.).– mitteilungen der kommission für quartärforschung der österreichischen akademie der wissenschaften, 8, 153–187, wien. nagel, d. (1997): dicrostonyx gulielmi (lemming) aus der höhle von merkenstein/niederösterreich.– wissenschaftliche mitteilungen aus dem niederösterreichischen landesmuseum, 10, 225–230, wien. oksanen, t., oksanen, l., dahlgren, j. & olofsson, j. (2008): arctic lemmings, lemmus spp. and dicrostonyx spp.: integrating ecological and evolutionary perspectives.– evolutionary ecology research, 10, 415–434. pavlinov, i.ya., kruskop, s.v., varshavsky, a.a. & borissenko, a.v (2002): terrestrial mammals of russia. an identification manual.– kмk press, 298 p. [in russian]. prost, s., smirnov, n., fedorov, v.b., sommer, r.s., stiller, m., nagel, d., knapp, m. & hofreiter, m. (2010): influence of climate warming on arctic mammals? new insights from ancient dna studies of the collared lemming dicrostonyx torquatus. – plos one, 5 (5), e10447. doi: 10.1371/journal.pone.0010447 rabeder, g. (1981): die arvicoliden (rodentia, mammalia) aus dem pliozän und dem älteren pleistozän von niederösterreich.– beiträge zur paläontologie von österreich, 8, 1–373. seetah, t.k., cardini, a. & miracle, p.t. (2012): can morphospace shed light on cave bear spatial-temporal variation? population dynamics of ursus spelaeus from romualdova pećina and vindija, (croatia).– journal of archaeological science, 39, 500–510. doi: 10.1016/j.jas.2011.10.005 sesé, c & villa, p. (2008): micromammals (rodents and insectivores) from the early late pleistocene cave site of bois roche (charente, france): systematics and paleoclimatology.– geobios, 41, 399–414. tsytsulina, k., formozov, n. & sheftel, b. (2008): dicrostonyx torquatus.– in: iucn 2012. iucn red list of threatened species. version 2012.2. <www.iucnredlist.org>. downloaded on 08 march 2013 villa, p., sánchez goñi, m.f., cuenca bescós, g., grün, r., ajas, a., garcía pimienta, j.c. & lees, w. (2010): the archaeology and paleoenvironment of an upper pleistocene hyena den: an integrated approach.– journal of archaeological science, 37, 919–935. wilson, d.e. & reeder, d.m. (2005): mammal species of the world. a taxonomic and geographic reference (3rd ed.).– johns hopkins university press, 2, 142 p. internet source: http://en.wikipedia.org/ wiki/northern_collared_lemming. downloaded on 01 july 2013 manuscript received march 15, 2013 revised manuscript accepted july 26, 2013 available online october 16, 2013 geologia croatica 45 127 150 10 fig. 2 tab. zagreb 1992 udc 551.35 (450) scientific paper evolution of the southern margin of the julian basin with emphasis on the megabeds and turbidites seqence of the southern julian prealps (ne italy) giorgio tunis1 and sandro venturinp key words: eastemfriuli, megabeds, paleogene, julian basin, basin evolution from the maaslrichtian up lo the early eocene, the julian (or slovenian) basin is characterized by a mixed siliciclastic/carbon­ ale deposits system which exhibit complex sedimenlalion pallerns depend ing on various controls: sea level changes; tectonic move­ ments in both carbonate platform and northern source areas; sub­ sidence; proximity/distality to siliciclastic, calciclastic, allodapic (carbonate) sediment source areas; abundance of terrigenous detri­ lus; paleomorphology of the slope of the friuli platform, the main source of carbonate detritus. the depositional sequences ofthe julian basin are the result of these controls and their interaction. herein the examination of the stratigraphic sections is restricted lo the middle paleocene up to the early eocene ("flysch di masarolis" and "flysch del grivo "),where the most important carbonate megabeds are recognized. fourteen stratigraphic sections of the "turbidites with megabeds" sequence were examined (mainly along the n-s direc­ tion). all sections are located near the southern margin of the basin, at the foot of the slope of the north-eastern edge of the friuli plat­ form. comparison of log s revealed marked differenoes in the thickness of the megabeds and of the interbedded calciturbidites and siliciclaslic turbidites . this could be ascribed to the proximity to the source areas of mega beds and to the abrupt stope morphology. by means of the litho-biostratigraphic analysis of the sedin1ents which filled the julian basin, the provenances from the main source areas are outlined. the prevailing calciclastic detrilus (ce ,i) mixed with allodapic carbonate sediments (ci) came from the south; siliciclastic detrilus (n ce) mixed with other calciclastic detritus (ce, ii) from n, nw as consistently indicated by paleocurrent directions; minor (and late) mixed carbonate sediments (ce, ill) came from ne. a rough sedimentary balance comprising megabeds, thick beds, multisource turbidites (siliciclastic, carbonate, mixed plus couplets) is calculated. an auempt to apply the eustatic sea level curve of haq et al. (1987) to maastrichtian-paleocene and eocene deposits of the julian basin is made. lowstands of the maastrichtianpaleocene and of the late ypresian are well recognizable. more problem s arise upon examin­ ing the "flysch del grivo " section which is slrongly controlled by tectonic mechanisms. the triggering mechanisms for mega bed em­ placement in the julian basin is related to seismic activity along the southern border of the basin. in conclusion, the "turbidites with megabeds" sequence is integrated within the framewot;k of the geo­ logical evolution of the julian basin. l. introduction the julian basin (or the slovenian basin accord­ ing to the slovenian authors) was a narrow, elongated basin limited by a carbonate platform (friuli platform) along its southern border. this basin, located in the julian prealps, from the maastrichtian up to the early eocene was character­ ized by mixed siliciclastic/carbonate deposits which exhibit complex sedimentation patterns depending on various controls: sea level changes; tectonic movements in both carbonate platform and northern siliciclastic source areas; subsidence; proximity/distality to siliciclastic, calciclastic, allodapic carbonate sediment source areas; abundance of terrigenous detritus; paleomorphology of the slope of the friuli platform, the major source of carbonate detritus. in tectonically active settings, such as the julian basin, a complex interplay between tectonism, eustatic sea level and subsidence, as major controls, is accountable for the sequence development. within the stratigraphic framework of the j ulian basin, deposits of megabreccia, breccia beds, carbonate megabeds and thick beds are clear evidence of tectonic activity along the margin of the friuli platform (tunis & venturini, 1985). this article focuses allen tion on the period between the late paleocene and early ypresian, where the ef­ fects of the dismantling of the friuli platform have been more pronounced and have originated spectacular mega beds. these mega beds are perfect marker horizons in geological mapping. in the conclusion, these data are integrated in the framework of the geological evolution of the julian basin, with the aim to underline the rela­ tions between depositional sequences and the above­ mentioned control ;nechanisms. 2. geological setting of the julian basin the stratigraphic framework .of the sequences of the julian basin (julian prealps and tolmin mountains) and of the surrounding friuli platform and slope was out­ lined by feruglio (1925a), fabiani et al. (1934) and more recently by buser & pavšič (1978), cousin (1981), tunis & venturini (1984), pirini et al. (1986), tunis & venturini (1986), buser (1987), tunis & venturini (1987). from the paleogeographic point of view, during the j urassic, the region of the southern j ulian prealps became a transition area between the friuli platform, located on the sw, and the julian basin, located on the ne in the northern j ulian prp.alps and tolmin mountains. this 'istituto di geologia e paleontolog.ia, universita degli studi di trieste, p.le europa, l, 34127 trieste 3 agip-snor, ufficio stratigrafico, via del march es alo, 48023 marina di ravenna "' v .. u ·~ e u .. . sn ~ " e oo ~ n (};) /l' 4 · (.j.udine. a, ~2 122:::1 1 3 o 5km l l l l l l norrheriv, ... .. ... iit. iuiuit b , . . l s. b. ~ ..... ~ 4.j ~ o "' " fig. l · location map showing distribution of the jlysch outcrops in the study area. 1.· maastrichtian deposits. 2. paleocene-eocene deposits. 3. examined sections of figs . 3,4,5,6 and ·tab. l. s.b. =state border ~ ~_, ljuiljaia ,..~ . ~ e tunis & venturini : evolution of the southern margin .. . setting underwent only slight changes during the. cre­ taceous (tunis & venturini, 1986). at the campanianmaastrichtian boundary, the paleogeographic situation abruptly changed in correspondence with the first alpine tectonic phases. tectonics caused shifting of the southern border of the julian trough to a sw direction accompanied by dismantling and withdrawal of the friuli platform margin. during the maastrichtian, with the arrival of siliciclastic material of northern origii1, the flysch deposition began, slowly extending to the southernmost areas, to today's southern julian prealps; natisone mountains and the western sector of banjšice plateau (pig. 1). within the flysch, calciclastic thick beds and breccias are widespread, but the first important megabeds are quoted in the middle paleocene, in the "flysch di masarolis". however, the typical "turbidites with megabeds" sequence is represented by the "flysch del grivo " (upper paleocene lower eocene) . depocenter of the basin was located along the kobarid­ tolmin line (w. slovenia), that corresponds to the axis of the j urassic-cretaceous basin. prevailingly siliciclastic turbidites filled the julian ba.sin during the uppermost part of the ypresian up to the earliest lutetian. during the early lutetian a rapid progradation of prodelta, front and deltaic plain deposits occurred from the north, probably related to a tectonic uplift (venturini & tunis,.in print). . as far as provenances of sediments are concerned, litho-biostratigrapic analyses have been performed on coarse arenites with the aim to characterize and separate · the main turbiditic sequences. by these analyses, still in progress, different lithotypes and frequencies have been detected and the derivation of detritus from the main source areas has been outlined. the calciclastic (or calclitllitic) detritus (ce, i) derived from the dis­ mantling and breaking off of tlle friuli platform margin, . and generally, can be found mixed with allodapic detritus (cl). allodapic carbonate turbidites (sensu meischner, 1964) are coeval sands and muds of the outer platform which slided down slope by turbiditic processes. this source (ce, i + ci) was the most important during the late paleocene-early ypresian (pig; 2). later, ce, i progressively decreased, as did ci, although at a slower rate. siliciclastic detritus (nce, l) mixed with other carbonate detritus (ce, il) came from n, nw as con­ sistently indicated by paleocurrent directions (venzo & brambati, 1969). herein, mention should be made of the constant and sometimes remarkable presence of volcanic rocks, in particular diabases, which may re­ veal to have an important paleogeographic and tectonic signiflcance. siliciclastic resedimentation shows several acmes during the middle maastrichtian and tlle middle­ late paleocene and increases at the ypresian-lutetian boundary (cf. last chapter). minor and late mixed contributions (ce, iii+ nce, il) came from ne. they are well documented during the lutetian final filling stage. 129 3. an outline of stratigraphy of the sequence with "megabeds and tur­ bidites" prior and after the first world war, the region of the southern julian prealps was geologically investi­ gated by numerous authors. feruglio (1925 a, b) deserves to be mentioned for the most exhaustive de­ scriptions of this territory. the author described the stratigraphic sequence of tlle southern julian prealps and, in particular, he made a distinction between a lower flyschoid complex characterized by extremely thick bodies of coarse conglomerates ("conglomerati pseudocretacei") and by interbeddings of sandstones and maris, and an upper flyschoid complex that mainly consists of a sequence of sandstone and mari beds. fer ug lio (1925a) . numbered the thick conglomeratic beds from l to 25, a numefation that has been kept in this text, where megabeds are preceded· by the letters mb. however, if compared with the original feruglio-s numeration, there are still some ambiguities when identifying some minor megabeds on the field. in the 'sos and during the following years, relatively few regional and stratigraphic studies were carried out in the region examined. recently, new researches and geological mapping have been carried out by cousin (1981), tunis & venturini (1984), pirini et al. (1986), tunis & venturini (1987), etc. the thick sequence where the most important carbonate megabeds are recognizable, was subdivided into two informal stratigraphic units, called "flysch di masarolis" (pirini et al.,l986) and ''flyschdel griva" (tunis & venturini,l987) respectively. the "flysch di masarolis" (middle paleocene-upper paleocene) mainly crops out in the central-eastern sector of the natisone valleys and extends to the banjšice plateau region (trušnje) in western slovenia. this unit is characterized by predominant medium-thick siliciclastic turbidites consisting of a sequence of quartz-litharenite and gray marl beds. in sandstone beds, bouma's intervals tb,tc;td and, more rarely, tlle interval ta can be ob­ served. carbonate proximal turbidites and, occasion­ ally, paraconglomerates rich in chert pebbles are interbedded within the siliciclastic turbidites. this sequence is sporadically interrupted by thick graded carbonate megabeds; the greater thickness pertains to megabed 2 which reaches up to 55 m in the l udrio valley. a giant polyphase megabed originated by colossal submarine slides named "mt. loanaz megabed'~ (pirini et al., 1986) deposited at the top of the "flysch di masarolis". this megabed corresponds to feruglio's layer nr. 3 (1925a); with it tunis & venturini (1987) mark the beginning of tlle "fly seh del grivo" sequence (upperpaleocene-lowereocene). the "flysch del grivo " is characterized by several types of megabeds such as complex megabeds, composite megabeds, carbon­ ate megaturbidites, carbonate massive tllick beds. the megabeds roughly make up 1/2 of the entire thickness 130 geologia croatica 45 poleoceneeocene boundary cučceo . . . . m.bernodio • a . • . o lo km ~ § d . j. 2 3 ~ 7 8 ·sovec·,-_ -_ a , __ --....... ----. 7----e . .kobo rid .. -.. . =. m.sobotino a a~ ~--* "'"..-~ lo oo> 4 5 6 fig. 2main source areas of detritus at the paleocene-eocene boundary. l) friuli carbonate platform. 2) slope. 3) basin. 4) palaeofaults: nw-se trending dinaric faults and ~e-sw trending antidinaric faults . 5) ce i (southwestem inputs). 6) ci (southwestem inputs). 7) ce iii and minor nce contributions (northeastem inputs). 8) nce +ce ii (nort western inputs) . of the sequence. the importance of the megabeds for correlation has been emphasized by giving names ~ -· the most important of then.: e.g. "vernasso complex layer" or mb ll (gnaccolini, 1968), "mt. ioanaz megabed" (mb 3), "mt. staipa-topli uorh megabed" (mb 6), "mt. carnizza megabed" (mb lo) and "porzus megabed" (mb 15), (tunis & venturini, 1985; tunis & venturini, 1987). the megabeds gradu­ ally become thinner and less frequent in the upper part of the section. between the megabeds, siliciclastic turbidites, carbonate turbidites, hybrid (mixed) sand­ stones, massive calcarenites and conglomerates (debris flow) can be observed. the "flysch del grivo" extends from the west to the east from the mt. faeit-zimor t. area, across the natisone valleys and the goriška brda as far as the banjšice plateau (anhovo region). west of the river tagliamento, the "flysch della val tremugna" (sarti, 1979) could also be related to the "fl ysch del gr ivo " (venturini & tunis, 1991). the "turbidites with megabeds" section outcropping in goriška brda (slovenia) is known in literature as "kožbana beds" (pavlovec, 1966; cimerman et al., 1974). tunis & venturini (1989) regard the tunis & venturini :evolution of the southern margin ... "kožbana beds" as synonyms of the "flysch del g rivo ". more precisely, in goriška brda, between mt. korada to the north and the village of višnjevik to the south, the middle-lower part of the sequence is present, comprised between mb 3 and mb 17. the region of anhovo was geologically investigated by kuščer et al. (1974) and skaberne (1987). here, between the villages of morsko and deskle (see fig. ll of skaberne, 1987) probably the upper part of the "flysch di masarolis" and the lower part of the "flysch del grivo" (mb 3 -mb 6) are out­ cropping. the "flysch del grivo" is overlain by the flysch di cormons (mar tini s, 1962) of the lower-middle eocene age (venturini & tunis, in print). within this formation, in the lower part, carbonate or hybrid big beds can be still observed, but the presence of megabeds is exceptional (tunis & venturini,l989). finally, the flysch deposits of the ajdovščina re­ gion (20 km east of gorizia) could be attributed partly to the upper section of the "flysch del g rivo" and partly to the lower-middle section of the flysch di cormons. engel (1974) reported the presence of carbonate megabeds in this region but, with the exception of two very thick breccia beds that resulted from impressive rock falls at the foot of a carbonate platform, to define them as big beds would be more correct, considering that their thicknesses are not exceptional. 4. main features of the ''megabeds and turbidites" sequence according to reading (1978), megabeds are unique deposits produced by exceptional events. some mega beds have been though t to be megaturbidites and interpreted as seismoturbidites (mutti et al., 1984) on the basis of a set of criteria (mainly thickness, volume and ge­ ometry). as regards terminology, the definition of megabeds is not univocal. according to some authors, megabeds are thicker than average beds by several orders of magnitude (mutti et al., 1984); according to other authors they must reach a critical thickness or, at least, they must be markedly thicker than interbedded layers (bouma, 1987). herein, true megabeds are defined by thicknesses exceeding 20 m, because they are evidently thicker than all the beds within the "flysch del grivo " sequence, and by the presence of the basa! breccia division in at least one of the examined sections. this is how megabeds are considered sensu stricto: mb 3, mb 6, mb 10, mb ll, mb 14, and mb 15 which show these features in all the measured sections. at the border line of this definition are the following beds: mb 8, mb 9, mb 131 16, mb 17, mb 21 and mb 22. all of the other thick beds are generally considered big beds. among big beds a distinction is made between major big beds, identi­ fied by fer u glio (1925a), and minor big beds. some of them could be defined as classic carbonate megaturbidites, some are massive or faintly graded calcarenites overlain by maris, and others are composite beds (marjanac, 1987). within megabeds s.s., the complex bed type prevails which is a couplet of megabreccia in the lower part and graded calcarenite­ marl in the upper part, sometimes with repeated intervals as illustrated by burrouilh et al. (1987), marjanac (1987). some megabeds are polyphase and thus they represent two or more superimposed megabeds: i. e. mb 3 and mb 15 (porzus section). in the explored area the complex layer of vernasso (gnaccolini, 1968) is the thickest megabed. it reaches the maximum thickness of 245 m near costa and borgo laurini di torreano. its fine calciruditic-coarse arenitic portion is known under the commercial name of "pietra piasentina" and is widely used in friuli. the precise post compaction volume of each of these beds is unknown, but mb ll and mb 3 roughly reach at least 25 and 19 krnj respectively. not less than ll krnj can be estimated for mb 15.but, the minimum width probable for these outcrops before the erosion must have been at least three times as much and the above-mentioned volumes are likely to be much higher originali y. fi g. 3 shows the lower part of the "flysch del grivo" along the cras-pedrosa sec­ tion, while fig. 4 illustrates the reant-mt. noas-forcis­ montina section which is the most complete of the "flysch del grivo ". with regard to the internal organization of a megabed, according to mutti et al. (1984), seguretetal. (1984) and labaume et al. (1987), the vertical section of the megabeds may be divided into five divisions grouped into two major segments of megabreccia and turbidite re­ spectively. there exist other models of complete mega bed sequences (bernoulli et al., 1981; klar v alaan, 1987; marjanac 1985, 1988; rosell & wieczorek, 1989, etc.) but the first model is preferred to emphasize the thick calciruditic unit (unit 3). unit l is a megabreccia which mainly consists of big blocks of shallow water limestones. individual clasts may have extraordinary dimensions, so olistoliths of the vemasso megabed have volumes up to 70 000 mj in the ltalcementi quarry ofvemasso, near b.golaurini di torreanocosta ("pietra piasentina" quarries) and up to 200 000 mj or 400 000 mj in the environs of clap, north of porzus and forame (cret del landri). smaller limes tone and mar l clasts can be found between the big blocks3 • frequently brec3 in the vernas so quarry the most common 1ithologies include: wackestone with orbitolinopsis capuensis of the hauterivian barremian age, grainstone with naujiloculina bronnimanni, dasycladaceae, rudis t fragments of the barremian-aptian age, grainstone-packstone with rudist fragments of sen oni an, packs tone with m inouxia of senonian, wackestone-packstone with scandonea mediterranea and sgrossoella of s anton ian, packstone with siderolites, orbitoides and rudist fragments of maastrichtian , pack stone with rudist fragments and globotruncana stuarti of maastrichtian, cherty fossiliferous pack stone of the upper cretaceous paie<>cene, wackestone with ostracoda and discorbidae of pa­ leocene age, packstone with melobesiae, corallinae and corals of paleocenc, packstone with discocyclinae of paleocene, packstone with o percu/ina and miscellanea of paleocene, packstone with alveolinae and cymopolia of palcocene, boundstone with corals of pa1eocene. and also marly 1imestones with globotruncanita gr. stuarti, g. arca, g.gr.linneiana of maastrichtian age, unfossiliferous maris, siltites, sandstones, calcarenites and carbonate breccias are present. 132 geologia croatica 45 cras peo rosa section ~ / u4 6 u3 u2 ul unit 5 lo u2 bis t~~~~~~ mari 5 unit 4 ~ gr oded 4 u5 . colcoren i te lo u4 u3 unit 3 r··· ... ~~ lithoclostic breccio ......... ·..: ( no~molly clos t supp.) ~:::;:·:;i~{ u5 unit 2 u4 9 u3 matrix supported u4 corbonate breccio unit 1 l! u3 ~ poorly sorleđ corbonate megobreccio u4 u3 u5 8 u4 .b u2 u3 50 u3 7 u5 40 u2 u4 6\ 30 20 ul lo 3 5 bis om fig. 3 cras-pedrosa section (lower part of the. "flysch del grivo"). key is given at fig. 5. in unit l : a = mushroom shaped breccia intrusion; b= olistoliths of shallow water carbonate; e = cannibalized blocks of older megabeds; in unit 2: d = discoidal marl clasts; e = rip-up siliciclastic turbidites. l, il =coarse resedimentation events. arabic numerals symbolize individual megabeds. fig. 4 reant-mt. noas-forcis-montina section ("fly seh del grivo"). symbols for units as in fig . 3. key in fig. 5. close-up of the upper part of this section plus younger beds shown at fig. 5 (mt. navaret ll cioch section). tunis & venturini : evolution of the southern margin .. . reantm.noas forcismontina section l u4 17 u3 16 ll u2 15 ul 14 bis 10 u2 bis 14 us u4 10 u3 u2 ul 13 u5 12 u4 9 u3 u5 \ 8 u4 u3 u5 7 u4 j u4 u3 u4 u3 u2 us u4 u3 u2 ul u4,5 u2.~ us u4 u3 uz ul u5 u4 u3 us 22 21 20 19 /""' 18? !';;.;:,-:;,;.,::-;\ \ 133 us u4 u3 u2 u4 u3 u2 u3 u4 u3 50 40 30 20 10 5 om 134 u2 dl 02 oi c2 c2 02 c2 oz!oii cz cz cz o z c2 02 02cz dl 0201 c2 d2 oi dl cz oi 02 dz t'"tt"ttt"'t---p. 1· e. cgi. cobb le m. nava ret il cio ch section c2 c2~ l c2 cz cz dig cz c2 c202 c2 c2 cz e cz cz c2 c2 c2 oi oi oi die oi cz dl c2 cl edi c2 dic2 cz"!: c2c2 c2 cz cz c2 o1cz oi u5 geologia croatica 45 cl u4 u3 u2 c2 cz c2 e c2 cz c2 dl c2 oi oi 20 c2 10 5 4 3 2 l om tunis & venturini :evolution of the southern margin ... key: lilill!hhhi ~ \\ \\~ ijjjj \ ·\ >< mar l hemipelogite hybrid areni te limestone lithic sondstone couplet thin~ to medium bedded sondst9ne with mudstone interbeds l oi, dz,c2,el (sondstone in otoci< l thin bedded sondstone and mudstone ( 01,02) (sondstone in black l corbonate turbidite 1 cr, cz, or, o2l massive colcorenite two layer bed con9tomerote l breccio rich in cherty pebbles on d cl oy chips pebbly mudstone corbonate big bed covered fau lt 135 fi g. 5 -detailed stratigrapic section of the upper pan of the "flysch del grivo": mt. navaretll cioch section. the thickest siliciclastic and calciclastic turbidites are indicated by letters cl, c2, dl, d2, d3 and e according to the classification of the turbiditic fa­ cies of mutti & ricci lucchi (1975). grain size scale: p= peli te; f =fine sandstone; e= coarse sandstone; cgi= conglomerate (pcbble). 136 cia blocks cannibalized by the huge sediment gravity flow can be observed. · large olistoliths of breccia beds and calciruditic­ calcarenitic beds are common in mb 3, mb ll and mb 15 (figs. 3 and 4). thus, the original overall number of megabeds must have been higher than what can be ob­ served today. base of the u nit l shows an erosional plane contact, but also a sharp contact (sometimes breccia di­ rectly overlies a sandstone bed). often, siliciclastic turbidites underlying the megabed do not appear to be strongly deformed by the load. transition from the unit l to unit 2 is gradual. unit 2 is also carbonate megabreccia, but can be recognized for the lack of large limes tone olistoliths, for the numerous disk shaped clasts of calcareous mud­ stone and for the rip-up siliciclastic turbidites with some interbedded calciturbidites. these blocks of turbidites are also present in the unit l, though less abundant. some mud blocks are armoured by breccia fragments. within the mb ll the thickness of interval containing rip-up turbidites is striking, reaching about 60 m (quarry of vernasso). even more than unit l, unit 2 is strongly matrix­ supported, but in the upper part pebble to cobb le grain­ size of limestone clasts prevails, and the matrix content decreases. unit 3 is a calcirudite which can reach 25-30 m in thickness (mb ll in fig. 4). within thicker megabeds, unit 3 shows a transitional contact with the underlying unit 2. more often, the contact plane between the two units is sharp and deformed by loading that had formed big flame structures. sometimes mushroom-shaped brecci~ intrusions, penetrating the calcirudite unit, can occur. unit 4 is mostly a normally graded calcarenite, iden­ tical to a carbonate megaturbidite. beside normal grad­ ing, this unit displays parallel-lamination, rippleand convolute-lamination. in some cases the unit 4 is char­ acterized by the alternation of massive, parallel-laminated and rippled calcarenites: i.e. composite bed (second phase of mb 3, mb 14 and mb 15). here it is possible to observe flow direction changes as indicated by ripple orientation. in other examples unit 4 is only graded in the lowest part (few centimetres) and massive in the remaining portion and/or laminated in the upper part only. everywhere, within this unit, water escape structures are rather common. the upper part of the megabed is represented by thick massive mari, occasionally laminated, that has a transi­ tional contact with the underlying calcarenites. the mari cap may reach a considerable thickness: mb ll is 45 m thick and mb 3 as much as 60 m thick near bocchetta di s. antonio (pirini et al., 1986). the main lithofacies interbedded with the megabeds are shown in fig. 5. description of sedimentologic characteristics of these lithofacies is not the purpose of this article, but in short, one may state that siliciclastic distal turbidites and proximal calciturbidites predominate in the lower-middle part of the "flysch del griva" se­ quence. siliciclastic, mainly proximal, turbidites prevail in the upper one. the proximal features of these turbid­ ites may 'be related to the south-south-eastward prograding geologia croatica 45 of deltaic complexes which made up the main source of nce i detritus. mixed siliciclastic and carbonate lithofacies (hybrid arenites and limestone-quartzarenite couplets, sensu kelling & mullin, 1975; tunis & venturini, 1984) are very frequent in the upper part of the section of "flysch del griva", while resedimented carbonates (calciturbidites, massive calcarenites either faintly laminated or graded at the base, two layers (sensu krause & oldersha w, 1979) are ubiquitous. 5.description of the examined sec­ tions: lateral and longitudinal v aria tion of megabeds as regards the stratigraphy of the "flysch del griva ",about thirty sections have been measured in friuli, from the cergneu area to the west to the !udrio riv.er to the east, and six sections in goriška brda (slovenia). these sections mainly follow an-s direction. their original locus was near the southern margin of the basin, at the base of the slope of the friuli platform. some sections, includ­ ing the composite type section of t. grivacolloredo, have already been published (tunis & pirini, 1987, tunis & venturini, 1987). here, respectively lo and 14 new sections are selected and illustrated in fig. 6 and tab. l. fig. 6 illustrates the marked differences in the thick­ nesses of megabeds and carbonate big beds, the differences in the thicknesses of the various units present within the mega beds and of the pockets of the siliciclastic and carbonate turbidites interbedded with the megabeds. usually one can observe that the stronger is the development of the megabed and of its megabreccia unit in particular, the th inner is the set of the underlying turbidites. even the set of the overlying turbidites shows smaller thicknesses. with regard to megabeds, these differences may be especially ascribed to the proximity of the source area and to the steep slope morphology. unfortunately, the extension of a single megabed cannot be followed across the basin for more than 5-6 km, owing to the present structural arrangement of the southern j ulian prealps and to the post-ypresian erosive phases. the exception to the rule regards the upperpartofthe ''flysch del griva" sequence observed near the villages of monteaperta and micottis. herein, thick and very coarse siliciclastic deposits are interbedded with "relatively more distal" megabeds. thus, the proximal zones of megabeds are characterized by very thick megabreccia divisions; but, more distally, the lateral variation of their internal organization is un­ known. however, it is plausible to think that mega beds extended basinward for several kilometers4 • souquetetal. (1987) and rosell & wieczorek (1989) respectively proved that the megabeds in the cretaceous and in the eocene of the pyrenees evolved in their distal parts, into normal carbonate turbidites. in the examined sections, one can assume that at least some calciturbidites and some big beds (for instance, the big bed between mb 14 and mb 15 in fig.6) are distal extensions of submarine slides smaller than those that tunis & venturini :evolution of the southern margin ... originated the megabeds. tab. l tentatively explores the proximity/distality of megabeds from the examination of 13 sections. the overall thickness and the ratio of thicknesses of the unit l and cumulative thicknesses of all other units are taken into consideration, and presence of giant olistoliths is also indicated. the comparison is drawn in different sectors of the southern margin of the basin.the table shows that mb3 is very thick in the middle sector. this megabed, however, reaches great thicknesses even in the !udrio valley and in slovenia, near mt korada (tunis & pirini, 1987) and at anhovo (skaberne, 1987), while towards nw it is 100 m thick near prossenicco and mt. oveiach (platischis). mb 6 is considerably thick eastwards, less thick in the central-western sector where, however, the ul/u2-5 ratio is very high. mb 6 shows a limited thickness westwards (20 m near platischis). as regards mb ll, the maximum thickness is recorded in the western sector, where the ul/u2-5 ratio reaches extremely high values (0.46 near b.go laurini di torreano). eastwards, the megabed considerably diminishes; westwards it gets gradually thinner (mt. carnizza, zuffine plateau, mt. cladis) until it reaches 65 m near cornappo, where it is cut off by the periadriatic overthrust (pirini et al.,l986). mb 14 and mb 15 are also thinner eastwards, more developed in the middle area, between vernasso and valle­ colloredo, they thin down in the t. griva di raschiacco valley and get thicker again in the central-western sector where the maximum thickness is reached as well as the highest ul/u2-5 ratio. . this ratio can not, of course, be used as an absolute index of proximity/distality to the base of the slope; among the other things, it is not likely that equivalent volumes of material have detached all along the slope and the platform margin. still, the considerable ul thickness, the presence of giant olistoliths, the limited thickness of the underlying turbidites and the poor development of the over lying siliciclastic turbidites (the lateral expansion of siliciclastic turbidites towards the margin of the slope was probably confined. to the morphologic obstacles produced by the submarine slides) are important clues of proximity s.s. just like the ab­ sence of large olistoliths, the limited ul thiclpless or its absence and the greater development of overand underlying turbiditic siliciclastic sequences allegedly indicate conditions of a "relative minor proximity" of the same megabed. in order to explain the variations in megabed thickness along the edge of the basin, a further factor should be taken into account. the ac:tivation of normal dinaric 137 (nw-se) faults along the slope of the friuli platform otiginated the megabeds5• however, at the same time, ne-sw trending antidinaric faults, orthogonal to the former and acting as transfer faults, were active (fig. 2). their presence and position is supposed where the greatest differences within the type section of the "flysch del griva" are found, in areas where it is even possible to observe the separation of some important megabeds into several stumps. these palaeofaults, probably in­ herited from the cretaceous,. are thought to have acted as a series of morphologic steps and to be the direct cause of the overall variations that some megabeds (mb 3, mb 6, mb ll and mb 15) miderwent in a direc­ tion parallel to the axis of the basin. 6. sediment ary proces ses and origin of megabeds as far as sedimentary processes are concerned, the megabeds may be considered as co:nplex beds which were deposited by a range of sedimentary processes: rock fall and debris flow with combination of supportive mechanisms (unit 1), debris flow (unit 2), deposition from a waning turbulent flow and partly grain flow (unit 3) and hi;;h-density turbidity currents (unit 4 and 5). according to hampton's experiments (1972) the density currents followed closely after or evolved from the de bris flow. another possibility is that carbonate detritus was resedimented from the same source by a series of sedim en tary processes that progressed in a close succession. such processes could be connected to a retrogressive sliding that generated successive coarse sediment gravity flows (calcirudites connected to grain flows, pebble avalanching along the slope, etc.) and turbidity currents. in many cases, the deposition of unit 4 was very quick, according to the ubiquitous water escape structures (water escape pillars, dish, etc.) and the sedimentary event was probably single. however, in other cases unit 4 can be regarded as a "composite turbidite" (sensu marjanac, 1987). fig. 7 indicates the frequency of the major sedimentary processes in­ ferred from the sedimentological characteristics of the different units. percentages are related to the thicknesses of megabeds and major big beds observed in the series typical of the "flysch del grivo ". topography presented is idealized while the den se lines represent dinaric faults active on the friuli platform. rock fall and debris flow mechanisms accounted for 1/3 of the total thickness of big beds and megabeds (about 260 m as against 760 m). so extraordinarily h ug e sediment gravity processes characterize the "flysch del 4 bonazzi & tunis (1990) report, on the basis of mineralogic analyses performed on the clayey fraction of turbidites that maastrichtian flyschoid units are characterized by illite crystallinity index typical of anchizone. according to these authors, the metamorphic degree is mainly due to sediment loading. thus, in spite of the fact that in the julian prealps there are no deposits young er than the middle eocene, it may be assumed that the maastrichtian flysch of the natisone and isonzo valleys was covered by the paleocene-eocene flysch. the pebbles and cobbles of the deltaic environment of the flysch di cormons are commonly composed of lithotypes coming from the paleocene-eocene flysch (venturini & tunis, in print). this leads to think that the julian prealps, which lifted during the lu teti an, are the most probable source area of the cobbles. 5 for instance, this can be observed in the lud rio valley where the flysch sutures in on la p, in a sw direction, the collapsed paleomargin of the friuli platform faultblocked by a set of subvertical dinaric faults (tunis & venturini, 1987; sartorio et al., in prep.). 138 (2) (3) s. antonio clap (4) (7) valle colloredo (6) canebola cras (9) re ant monti na m.carnizza porzus sgubla pedrosa 22= = zle=:\ zo~ 19c:::::::l 17~ 16~ = = = 14r:'­~ 13= 12= e = toe=\.. a= 7= t9c:= 1817= tsb::l a= 7~ = 5==>-4= z tr··----, 2019~ 18= e 10 bisc:::::::j 9= 6bis= 5= 4c:::= 23= 22~ 211\ 20~ 19~ 18= 17~ t6c=:1 ~ e==. 14d 13= 12= e. p. geologia croatica 45 (10) (ll l vernassino mac ota (12) (13) mernicco sc rio' vernasso m. cau (castelmonte) 15~ 8&o8 • .... e 14~ 13==>-12~ 10~ p• poliphose e=connibotislic tendency c=::j us r==:j u4 c:=::j u3 c=:::j u2 1đhr1j ul 200 iso too so 20 om fig. 6 schematic column ar sections from wto e of the "flysch 11.:1 grivo" showing only mega beds and big beds . ln megabeds, different units are represented by different width s; key on the right of the figure .. the blanks represent both the exposed and covered sequences. for graphic purposes, the sections have been constructed by taking mb 3 and mb ll taps as references. tunis & venturini :evolution of the southern margin ... brdice< 14 > kožbana < 13 > mernicco scr jo" mt.cau < 12 > (castelmonte) < 11 > vernassjno­ macota <lo) ve rnasso reant< 9 >monti na <s>prestento­ t.chiaro valle­ <7>colloredo cras (g)pedrosa < 5 > raschjacco­ t. gr ivo' + ~,.... ~ on r,.,. o m ll'! n m ~ o l n \on m ~ o + co c'o rl co ....,,..... n ~ o +~ no n ' o l +.-i \om« itl ~ o co o .-i r~ o co co n .-i ~tc no \0 on co ~· .-i o v:> n .-i .-i , o \0 .... ...-l n ~ o .... nn co ' o <4 >canebola~~ ~~ sgubla m~ ~ o co < 3 > s.antonio~.. ~~ ~~ ... clap o ~ ~------------------------------~--------~~------~-----4------~------~~ < 2 ) mt.carnizza­ porzus mt.iauer < 1 >le zuffine l +<" co m« \0 ' o l +en on ~ ' o co ..,. rl \0 , .. .-i o l +o ont< qo ' rl o 139 tab. l -thickness of megabeds and ratio between the thickness of unit l and the thickness of all the other units. measured sections from the west (l: le zuffine) to the east (14 : brdicekožbana, slovenia). the+ sign indicates a greater development of the megabed com­ pared to the measured thickness . in the ul/others ratio, owing to the poor outcrop exposures of the upper unit, the sign indicate s slightly lower values. the asterisk indicate s the pre sence of giant olistoliths. 140 n n ~ o -(j1 ~ o o -(j1 ~ o fig. 7 main sedirnentary processes which originated the megabeds and big beds of the "flysch del grivo". geologia croatica 45 tunis & venturini :evolution of the southern margin ... griva". the remainiqg 2/3s, inappropriately attributed only to turbidity currents in fig. 7, indicate the thickness taken by units 3, 4 and 5. these units have been originated by various processes, among which the high density turbidity currents prevail. some small intraformational slumped beds can be mostly found in the upper part of unit 4 (for example mb lo near clap and mb 13, near porzus). they indicate that some movements of sediments (sliding and/or more probably slumping) occurred after the deposition of the materials. the palaeotransport direction in the megabeds of the "flysch del griva" was mainly inferred by exam­ ining lithologies (from giant olistoliths to calcarenites). the same kind of detritus (mainly shallow marine upper cretaceous and paleocene limes ton es and paleocene or penecontemporaneous maris) is observed within all units of the mega bed am within all megabeds, and indicates a single source of detritus, and that is the friuli plat­ form located towards the south. the palaeocurrent data concerning calciturbidites indicate a longitudinal palaeotransport (from nw, like the siliciclastic turbidites) probably deflected from an original provenance from south-west. in some megabeds, opposite ripple orientations, which suggest directional changes of flow regime, have been obser':ed (mb 3 and mb 6). they represent possible consequences of reversals of turbidity currents in re­ stricted parts of the basin where voluminous flows reached the opposite side or opposing obstacles and reflected backwards or sideways (pickering & hiscott, 1985; marjanac, 1990 and 1991). however, no detailed explorations of palaeotransport directions were performed according to the internal structures of the friuli megabeds. the hypothesis of the possible proximity of morpho­ logical obstacles is supported by the fact that a large number of megabeds shows a very thick marly cap. mar ls may present thin laminations, which may mean that the maris formed from ponded turbidity current tails of voluminous flows (hersey, 1965; v an andel & komar, 1969; blanpied & stanley, 1981). very thick massive maris may indicate restricted environ­ ments, i.e. restricted basins, parts of the deep sea ba­ sin with obstacles, etc. (see marjanac, 1991). so, the j ulian basin was certainly single, rather narrow (50-60 km wide at the most) and probably character­ ized by a complex and differentiated bottom topogra­ phy. giant olistoliths and the exceptional volume of the megabeds indicate a catastrophic collapse of the platform margin and sl ope, that was probably initiated by a seismic shock. mutti et al. (1984) interpreted such beds as seismoturbidites. seguret et al. (1984), on the basis of two constraints, estimate that superfi­ cial earthquakes of m=7 would be required to initiate landslides in the south pyrenean basin. today most authors accept the seismic interpretation to explain the origin of megabeds, even though various triggering mechanisms exist. we think that megabeds of the julian basin point to exceptional initiation mechanisms because 141 they deposited in a highly tectonically mobile setting and they account for a volumetrically remarkable proportion within all other deposits (probably the highest proportion ever known in literature). since we accept the seismic interpretation, on the basis of our previous studies on the evolution of the basin, we think that extensional tectonics was responsible for the high seismicity along the margin of the friuli platform. during late paleocene-early eocene, important nw­ se trending dinaric paleofaults were active on the margin and slope of the platform to create conditions of enormous slope failures. the data collected indicate an instantaneous deposition for megabeds; tens of km3 of material were mobilized and resedimented in a short time. we hy­ pothesize the location of the faults on the slope for a further reason as well: according to seguret et al.(1984) the high acceleration necessary to liquefy and fluidize maris and therefore reduce frictional resistance, only occur in the immediate vicinity of the active fau l ts. in order to estimate the paleoseismicity of the basin, a rough sedimentary balance has been calculated in tab. 2. it includes multisource turbidites (siliciclastic, carbonate, mixed plus couplets), megabeds and big beds, massive calcarenites (either faintly graded or laminated at the top), isolated debris flows, hemipelagites and coarse thick sandstones. all these lithofacies, or association of lithofacies, have been distinguished in tab. 2 by their cumulative thickness and number of events. the "flysch del griva " sequence is divided into three intervals: the lower one is comprised between the base of mb 3 and m ll; the middle one is comprised between the base of mb ll and the top of mb 15, the upper one beg ins at the top of mb 15 and ends at the top of mb 23. the three segments have about the same thickness, but are characterized by different thickness ratios and number of events. intervals have been mea­ sured in the central part of the examined area and the values indicated in tab. 2 have been calculated by comparing and assembling 21 composite sections. the sequences of mt. ioanazs. antonio, t. griva di faedis, vallecolloredo and reant-montina are the reference sections for megabeds. the data are compared with those measured along two sections belonging to the unit underlying the "flysch del griva" and to the upper part of the "flysch del griva" sequence. the sequence defined as the "flysch di masarolis" was measured in the iudrio valley where mb 2 is particularly thick. the upper part · of the "flysch di griva" sequence has been measured between debellis and monteaperta, in the "more basinward" possible ubication and in the proximity of the pro grading deltaic complexes. the sequence of the "flysch di masarolis" takes up the middle-upper part of the unit and belongs to the p. pseudomenardii biozone. mb 3 still belongs to the p. pseudomenardii; the m. velascoensis biozone can be found immediately above. the transition between biozone m. velascoensis and biozone m. subbotinae is estimated between mb 7 and mb 8. biozone m .formosa appears a few meters above t . vl ..". .§ :0 8 u .. ·o. o ] ~ m :! r • -"u en ll) v (/)(/) en ..xen v ........ v )( oi u u ,.:-= u v u "u e ·.fen ·e ll) oo ·-v oi e en -ll) "u ll) ww :=.o o v a. 'o en en -o·--v v e ll) ll) v ov ll) u a. "u cij o o v-e oe:-= m. > ~ cij..; v e 'o·<tm cij cij o cij .o .o :l u "u o "u ·-"u ' ·v; o en en a. v .... .... u u o+: u .o .o·..... e>(.!) a. .... .... -o e :l u cij -o u u oiu ,_.o .o .o en u ::j .o o e ct > o-:.= 'o ... >.'w_ oo v o o cij v :l o .o ::: o v== ·::j :em ~s ~(jj u)u.2 ::r:.2 u o u en :t: (/) o u e._ (/) v "flysch del thick. 449 6,8 55,1 30 29,3 570,2 65 635 7,7 g rivo'" (n) events 1390 5 4 ll 7 (upper part) / / / / / / / !/ / 7 v v / thick. 167,3 33,4 24 134 8 0,9 3,1 3,1 373,8 98 472 4,03 = 15-23 --o events 860 26 81 9 l 3 6 17 1/95 > q: c) ..j thick . 26,3 17,1 4,3 356,5 3,7 0,3 1,7 409,9 53 463 1,26 uj ll 15 o events 86 19 ll 6 2 2 5 1/14 ~ u cl) thick. 48,7 39,2 6,6 268 7 . 1,3 2,8 1,2 374,2 145 519 1,05 ~ l1... mb 3 ll = events 221 31 23 lo 4 7 7 5 1122 / :/ / l/ / / / / / / l/ v '/ "flysch dl thick. 116,7 12 6,8 53,4 16,3 5,3 1,8 212,3 39 251,3 4,12 masarolis" l "t (middleupper part) events 406 37 26 2 7 13 8 1/203 'tab. 2 -cumulative thickness and number of events of the main lithofacies found in the "flysch di masarolis" and in the "flysch del grivo ". the data concerning the "flysch del grivo" result from the companson and assembling of 21 sections measured in the area comprised between the t. g rivo di faedis and the t. chiaro di torreano. also the basinal deposits of the upper pan of the "flysch del grivo", outcropping near monteapena are examined. thicknesses are expressed in metres. tunis & venturini :evolution of the southern margin .. . mb 23. the top of the monteaperta section probably reaches the upper part of the ypresian. as regards the "flysch del griva", the estimated duration of the studied interval comprised between two megabed markers (mb 3 and mb 22) is 2.7 m.y. tab. 2 shows the enormous role played by megabeds in the total thickness of the explored sequence of "fly sc h del griva". in the first interval, the megabed thicknfi:ss accounts for the 51.6% of the section (outcropping sequence plus estimated covered sequence): in ·the second interval, the thick­ ness of megabeds accounts for,as much as 77% of the section. in the l~ t interval it drops to 28.4%. al together, mega beds make up 1/2 (52%) of the "flysch del griva " that reaches the maximum thickness of 1454 m. the ratio between megabed events and siliciclastic turbid­ ites is very high too. in tab. 2 the values 1/22, 1/14, 1/95 are indicated in the first, second and third segment respectively. by including in the calculation the covered intervals, mainly ascribed to siliciclastic deposits, the values would be lower: the ratios between mega-events and normal events would be equal to 1/50, 1/130 and 1/120 or l/ 70 respectively for the entire sequence. still, there are some remarks that have to be made. first of all, the number of megabeds should have been higher than what can be observed today; as a matter of fact, there exist cannibalistic megabeds. secondly, originally siliciclastic turbidites also had overall thicknesses greater than those shown in tab. 2. the most important megabeds present a thick set of rip-up turbidites involved in the submarine sliding of enormous masses from the platform. we estimate that about 50-60 metres of medium-thin multisource turbidite sequence were removed by the slides. considering all the assumptions that have been made, one may assert that the siliciclastic detritus contributed not more than 25-28% of the bulk supply. the major siliciclastic supply regarded the last inter­ val (about half of the overall contribution). the ratio between thicknesses of siliciclastic turbidites and calciclastic detritus plus allodapic carbonate detritus (with the exception of megabeds and big beds) shows a virtual equality of the first two intervals, and an abrupt increase of the siliciclastic input in the upper interval. all these values refer to the margin of the basin; it is not possible to define what the situation was in the basin plain and what the volumetric relations were between the various lithofacies. as regards the frequency of megabeds, the periodicity of megabeds in the studied interval v aries from lx l 05 years (entire sequence) up to 7x l 04 years (interval comprised between mb 7 and mb 15) or much less (interval comprised between mb ll and mb 15). should many thick carbonate turbidites and massive calcarenites' turn out to be seismites, the repeat times will be con­ siderably shorter (halved or even less). on the other 143 hand, the mean repeat time of normal siliciclastic turbidites could be equal to 1.5x 103 years or less. thus, on average, megaevents were tens times less frequent than normal events. during the emplacement of the megabeds of the "fly sc h del griva ", the mean over­ all sedimentation rate was 53 cm/1000 yrs ·1 • the mean sedimentation rate of siliciclastic detritus was 15-18 cm/l 000 yrs·1 , that of the carbonate detritus was about twice as much. most carbonate detritus, however, is of calciclastic and not of allodapic origin. the sediment rates' of both siliciclastic and carbonate detritus show strong accelerations and sharp decreases. impressive increases of carbonate sedimentation rate occurred during the second interval. owing to the strong seismic activity, during long lapses of time ,metres or several metres/ 1000 yrs·1 of material probably deposited. on the base of the repeat time of megaturbidites and the sedimentation rate ofturbidites, mutti et al. (1984) identified two tectostratigraphical groups within the family of the alpine-apenninic flysch units: the typical and atypical flysch of cretaceous to eocene and oligocene­ miocene age, respectively. the later accumulated at a much faster rate in the troughs of the apenninic orogen. based on available data, the paleocenic-eocenic flysch of the julian basin is closer to the time-thickness distribution of the mamoso-arenacea formation. however, the two fly sc h strikingly differ in terms of lithology, provenances and geodynamic setting. finally, excep­ tionally catastrophic events are much more significant in the j ulian basin. considering the high seismicity, we have looked for evidence of palaeoseismicity based on the presence of megabeds in the tertiary basins of the eastern most sector of the southern alps, from the west to the east: bell uno basin, alpago basin, clauzetto basin, ajdovščina basin, brkini basin, trieste basin and central istria basin. however, not only mega beds suggest on palaeoseismicity but also some postdepositional phenomena, especially large flame-structures and injection-structures. during the lower eocene, two megabeds appear within the sequence of the flysch di bell uno. no mega bed has been identified in the alpago flysch; only one 7 m thick big bed is described by gnaccolini (1968). as regards the carnic prealps (clauzetto basin), only in the more ancient tertiary levels and, in particular, in the flysch deposits of basal eocene (m. subbotinae biozone) outcropping in the northeastern area (val .tremugna), imposing carbonate resedimentations ap­ pear. the flysch di clauzetto s.s. (middle-upper ypresian lowermost lutetian) is comparable to the flysch di cormons from the lithologic and evolutional point of view. in the vipava valley (ajdovščina basin) the flysch sedimentation began in the middle part of the lower cuisian age (drobne & pa vlovec, 1991). the lower breccia beds and carbonate big beds are then 'we do not know the criterion to defme seismite or aseismic turbidites in the other thick carbonate beds. at least thirty carbonate megaturbidites can be found in all the examined sections. they are 2 m or more thick and usually display the ideal bouma sequence (ta-e), often with a thin breccia carpet at the base. it is not possible to know if they mantled large part of the basin plain, but they surely reached high volumes. 144 penecontemporaneous 10 the megabeds of the middle-upper part of the "flysch del griva". in the brkini area, the flysch deposits are entirely ascribed 10 the lower eocene (orehek, 1991). ln brkini, in proximity to leskovec, at the base of the flysch sequence, pa vlovec et al. (1991) reported the presence of a megabed showing a 78 m thick basal olistostrome and calcarenite grading to mari at the top. macroforaminifers and nannoplancton indicate that the megabed belongs 10 the basal part of the middle cuisian age. this age might correspond to the uppermost part of the "flysch del griva" sequence. in the middle eocene of istria, magdalenić (1972) reported the presence of fluxoturbidites made up of limes tone breccias in the lower part, overlaid by foraminiferal microbreccia, sandstone of calclithite type and mari at the top. the most signifi­ cant megabeds can be observed near mt starai (vranja), gračišće (pićan) and kaščerga, where individual clasts of the basal unit reach 2-3 m3• in the same period, even in the trieste basin (trieste-koper sync line or savrinsko primorje syncline) carbonate big beds are present. in conclusion, the most important paleoseismicity evidence in the tertiary of the eastern southern alps is related to the evolution of the southern edge of the j ulian basin and the withdrawal of the north-eastern margin of the friuli platform. 7. evolution of the julian basin during the main d~positional stage ofthe flysch (maastrichtian-lower eocene), the julian basin was a relatively narrow trough; structurally it was represented by an asymmetrical graben (tunis & venturini, 1984; pirini et al., 1986). in the studied interval, the total thickness of the flysch units, examined bed by bed, by far exceeds 4000 m (fig. 8). most of these units are referred to paleoenvironments of the base of the slope of the friuli platform ("drenchia unit", "flysch dello l udrio", "flysch di mt. brleka" and "flysch del grivo") or even of slope ("flysch di clodig" and "flysch di calla" that are characterized by thick pockets of slumped beds). for the "flysch di masarolis" deposits, one may assume a paleoenvironmental situation of "relatively minor proximity" to the slope. only the lower maastrichtian deposits outcropping between tolmin and kobarid may be partially attributed to basin plain environment. information on the opposite side of the basin is scan t. kuščer et al. (1974) report the presence of maastrichtian olistostromes of northern provenance at bovec (slovenia), near the northern margin of the julian basin. information about the north-western edge that provided access to the basin for nce sediment (fig. 2) is even less. thus, under unfavourable conditions, an attempt was made to apply the eustatic curves of haq et al. (1987) to the maastrichtian-paleocene-eocene sequence of the julian basin which was strongly controlled by tecton­ ics. as far as eustatism is concerned, published models indicate that most siliciclastic detritus reaches the deep geologia croatica 45 sea during sea-levellowstands, when the sediments bypass the slope (v all et al., 1977; shanmugan & moiola, 1982; vail, 1987, etc.). conversely, ba­ sin siliciclastic sediments decrease during highstands, when a large part of the detritus carried by rivers re­ mains trapped in deltaic areas. in contrast, the response of carbor..ate systems to the changes in sea level is al­ most opposite to that observed in the siliciclastic sys­ tems (kler & pilkey, 1971; mullins, 1983; droxler & schlager, 1985; boardman et al., 1986). sedimentary responses to sea level changes of hybrid siliciclastic/carbonate systems result in the deposition of alternated siliciclastic and platform de­ rived carbonate deposits (hesse, 1982; haq et al., 1987; cook & miller, 1989; dolan, 1989; sarg,1989; yose & heller, 1989). the best correspondence with the curve of haq et al. (1987) can be found in the maastrichtian-paleocene and in the upper ypresian, where the lowstand phases (g. cantusa, p. pusilla, p. pseudomenardii, a. pentacamerata biozones) are characterized by massive siliciclastic turbiditic supplies (fig.8). turbidites show relatively proximal features. conversely, during the highstand phases, allodapic limestones (g. gansseri biozone) and/or fine siliciclastic deposits (nce, i) with dis tal characteristics prevail. the presence or absence of allodapic limestones is to be related to the produc­ tivity of the friuli platform margin. examples of al­ ternating high stand phases with resedimented allodapic carbonate and low stand phases with growth of turbiditic siliciclastic complexes are reported by dolan (1989), and are related to the presence of flat-topped carbon­ ate platforms. during lowstand phases this type of carbonate platform considerably reduces its productivity, while during highstand phases, it becomes an active source of intra-bioclastic detritus. these fundamental concepts advise against the application of models concerning environments characterized by terrigenous sedimentation to carbonate depositional environments. furthermore, they allow to subdivide the sequences within a basin characterized by hybrid sedimentation patterns and, if required, 10 assess the existence of different tectonic controls in the various source areas. the main problems of sequential interpretation raise from the examination of the "flysch del grivo" (late paleocene-early ypresian) and the "unit ofdrenchia" (earlymaastrichtian), as both sequences are strongly controlled by tectonics. the massive coarse carbonate resedimentation and the tectonic phases which have probably extended 10 the northern margin of the basin, totally mask the eustatic effect in these lapses of time. subsidence is the last but not least of the controls. the geohistory diagram offig. 9 has been constructed with time on the x axis and paleobathymetry on the y axis (estimated on the basis of the benthic/planktonic foraminifera ratio and benthic foram associations) and the thickness of the single intervals of the sequence. the resulting subsidence curve shows significant slopes during the .middle-upper maastrichtian and during the tunis & venturini : evolution of the southern margin ... 145 m.y. age bioeustatic curve l system tra ct li t h o l o gy m zones high low o'=>e1 \·· .. ·• sondstones, conglo. • . . . . hmerotes,siltstones ·e q~ -..... cio 0(\\ (delta) 4> ~ .... . q siliciclastic ... :j o .. . .. turbidites. _j x _._ "' ~ ...l. • -'rare amoiqomoled . _..._ e: sondstones/ -a.pen. . . • o • • o conqiomeroles ~ e 50e and ' o .......... . -'~ m. or. . _...._ . o colciclostic beds ·-'-. __._ ond ll) ~ ,• -lu 4> m .for. l'\ s thick beds . ... _.___ ~ 1000 a. m. sub. . __.__ . --->m. td. _._. -'.,...=::::::> ~ 6 m.vel. ~ . _.__ . 55 a 6 6 la. colciclost ic ~= .. ......._. __.__ e: e "' 1-o o o a 6 a a 6 mega beds "10 .&; ................... ·:j a. and big beds; ... 4 a a 4 6 ..... 11'1 , q.l a. o l hinbedded e: n: u .... " .... ·( .. "' .. "'"' .......... > o e: 6&6a6aaa66 ·siliciclastic ~ p. p us. "' o '-. .. . . ~ ..... ... ~ lurbidites . p-2000 ~j' "' u . __.__ 60 m.an . .. 6 6 6 a a "' 1m. un. '-_._ . -'"' •• • o • •• e ~ (~ .. ·;"a.,. e ( ........ ~ j''-~ .......... ~ o siliciclostic turbidite! ui .!!! 1-·~ .•. •. ~ ~ -o motrill·supparted con. e ... -.. ... -ci o glamerates and col. l "' o :j . ·.·.;, ·• o ciclastic thick beds. .. hs :::!! o "' 65 a. ~ . __..._ . .2 red maris and su bor_ e) -'• ~ o dinale sandslones . ......_ u g.euo. -allodapic limestones 3000 --o a.moy. z. sand stones __.__ -~ e g. con. -~ m and maris. o .. ·_.__ ...l. siliciclastic flysch. .... "; ls . . . . o .s:. e ~ some corbonate u o ··~ .. "10 1-70 oi jts . . . . . . :j bio beds . ·d .., ... ~ ......... ........ .... ll) ..: _._. oo o q ........ _._ 'o corbonate flysch . u o o ·u ~ . _..._ :! mar ls, calcisi ltites, 1-4000 h s o o •• o . o 0 :;: corbonate big beds, --'........ u e: ci g.col. smw .. rore sondstones . __.__ .. 75 e --o o g.ven. hs (teci. phase)~ : cherty plloaop1c u > llmestones fig. 8 ·comparison of the eustatic sea level curve and system tracts (after haq et al., 1987, simplified) with the upper campanianpaleogene clastic depositional sequences of the julian basin. on the left, stages and related planktonic foram biochronozones. ls = lowstand; hs = highstand; smw = shelf margin wedge. vl '<t .g .. 8 u .. "ob o ] o "' '<t .... maastricht ian donio n thanetian ypresian lu t . 70 65 60 55 50 g. tricor. g. gans. g. e. a. m g.eu.g.pse.js. trin.jm.u. m.o.p.p. p. pseudom. m. v. m.e-m.s m.f. m.or. m.p. h. ar. lio 95 520 275 35 80 lio lio 620 290 150 115 /~ sea floor ~ __ ./~---l.--------j'\"' r--------~t\ l-"'~r--------~ "" ------------------~ drenchio clodig j. b. co ilo mosorolis gr i vo' cor mons • 1 • r • . . p.:__1._ • --1..... • --'• _j_ , .. , . , . lj. lj. -l. lj. • lj. ll lj.. ll _..l_ • -l • --l-#-. ,, 0.-l-6-1-.o ·l . 1 . l· ... j_ age m.y. zone m /m.y. o f-1000 --e -! : f-2000 i .e -. 0.. (l) o f-3000 f-4000 unit lit h . -~ o ~ :0 ... ..8 ;( .!;! " " t/j ·~ .. p:) .~ '; ..... " -s 'o "' -o 0.. " -o ·~ .. t.l " -s 'o e e oi) .. :0 ~ ~ ~ " o 0\ oil ~ tunis & venturini: evolution of the southern margin ... 147 cividale ko ba rid matajur b ssw l compressive transpress ive phase l nne jmiddle eocene p.p.l ssw l e xtensional ph a sebocko rc l nne l maastricht ianpoleocenelower eo e ene l o 50km fig. lopalaeotectonic hypothesis of the structural setting during the maastrichtian-paleocene-early eocene (below) and middle eocene (above) of the boundary area between italy and slovenia, along the rosazzo -mt. mangart section. the maastrichtian-paleocene-eocene clastic deposits are shown in black. uppermost paleocene-basal eocene. in particular, in this second interval the marked subsidence results to be associated with imposing carbonate submarine slides (ce, i). in correspondence to these phases of maximum subsidence the most important withdrawals of the carbonate platform and the maximum expansions of the flysch basin took place (venturini & tunis, in print). furthermore, the rate of sedimentation may have ex­ ceeded 600 m/m.y. the expansion of the basin is likely to be connected with distensive-transtensive processes that are thought to have involved ancient mesozoic detachment surfaces (fig. 10). subsidence slowed down during the middle maastrichtian (g. gansseri zone) and the lower-middle paleocene, where carbonate resedimentations are mainly made up of allodapic limestone (ci). here, the sedimentation rate is lower than 100 m/m.y. the standstill of subsidence in the middle-upper ypresian pre-announces the liftings occurred in the middle eocene (fig. 10). in this period the basin was slightly filled, the southern slope has been progressively sutured, so the carbonate sediments (ce, i and cl) were almost completely absent. a similar situation was identified by marjanac (1991) in the eocenic flysch basins of dalmatia. in these basins, characterized by important carbonate megabeds, the author has highlighted the presence of distensive faults with a dinaric trend (about nw -se), released by a system of antidinaric transfer faults (about sw -ne). a close connection of turbidite and me g abed sequences with the migration of dinaric foredeeps, suggested by many of the authors who studied it, appears to be most unlikely (venturini & tunis, in print). the available data better fit a context of puli-apart and/or back -arc s .l. basins. from this perspective, eocenic compressivc phases which directly involved the examined areas are not the fundamental cause of the massive carbonate submarine slides, but have rather led to the 148 subsequent _filling of the basins. acknowledgements financial support from italian ministry of public instruction, murst 60% "evoluzione dei bacini sedimentari terziari", resp. g. catani. 8. references bernoulli, d., bichsel, m., bolu, h.m, haring, mo., hochuli, p.a. & kleboth, p. (1981) : the missaglia megabed, a catastrophic deposit in the upper cretaceous bergamo flysch, northern italy.eclogae geol. helv., 74/2, 421-442. blanpied, c. & stanley, dj. (1981): uniform mud (unifite) deposition in the hellenic trench, eastern mediterranean. smithsonian contribution to the marine sciences 13, 1-40. board man, mr., baker, p .a., dulin, a, ken1er, rj., hunier, g .e. & kiefer, k.b. (1986): banktop responses to qua1emary floctuations insea level recaded in periplatfoon sediments.geology, 14,28-31. bonazzi, a. & tunis, g. (1990): caratterizzazione mineralogica della frazione argillosa delle peliti '­ in base alla stratigrafia delle unite e formazioni clastiche cretacico-terziarie del friuli orientale e della slovenia occidentale (lugoslavia). atti tic. sc. della terra, pavia, 33, 199-234, . bo uma, a.h. (1987) : megaturbidites ·: an acceptable term?. -in: doyle, lj. & bourrouilh, r. (eds.): megaturbidites.geo-marine letters, 7/2,63-67. bourrouilh, r. (1987): evolutionary mass flow­ megaturbidites in an interplate basin: example of the north pyrenean basin. -in: doyle, l.j. & bourrouilh, r. (eds.): megaturbidites. geo-marine letters, 7/2, 69-81. b user, s. (1987) : development of the dinaric and julian carbonate platforms and the intermediate slovenian basin. -mem. soc. geol. it., 40, 313-320. b user, s. & pa všić, j. (1978) : migration of the upper cretaceous and paleogene flysch basin in the western slovenia. 9 jugosl. geol. kongres., sarajevo, 78-81. . cimerman, f., pavlovec, r., pavšić, j. & todesco, l. (1974): biostratigrafija paleogenskih plasti v goriških brdih. geologija, 17, 7-130. cook, h.e. & miller, j.f. {1989): late cambrian and early ordovician stratigraphy, biostratigraphy and depositional environments, hot creek range, nevada. 28th international geological congress field trip guide book t 125, 28-36. cousin, m. (1981): les rapports alpes dinarides dans les confins de l' ltalie et de la yougoslavie. soc. geol. nord., 5, vol. i and vol. ii, 521 + 521. dolan, j.f .. (1989) : eustatic and tectonic controls on deposition of hybrid siliciclastic/carbonate basinal cycles: discussion with examples. a.a.p.g. bull., 73/10, 1233-1246. geologia croatica 45 drobne, k. & pa vlovec, r. (1991) : paleocene and eocene beds in slovenia and in istria. in: introduction to the paleogene of sw slovenia and istria field trip guidebook. igcp 286 second meeting, postojna, 7-17. droxler, a.w. & schlager, w. (1985): glacial versus interglacial sedimentation rates and turbidite frequency in the bahamas. -geology, 13, 799-802. engel, w. (1974): sedimentologische untersuchungen im flysch des beckens von ajdovscina.gottinger arbeiten zur geol. palaont., 16, 1-65. · fabiani, r., leonardi, p., kossmat, f. & · winkler, a. (1937) : carta geologica delle tre venezie, foglio 26, tolmino. uff. idrogr.*r. magistr. acque venezia, firenze. feruglio, e. (1925 a): le prealpi tra l' isonzo e l'arzino. -boli. as s. agr. friul., udine, serie 7, 39-40, 1-30 l. feruglio,e. (1925b): cartageologicadelletre venezie, fog lio 25, udine.u ff. idrogr. r. magis tr. acque venezia, firenze. gnaccolini, m (1967): ll flysch dell' alpago (belluno). riv. ital. paleont. , 73/3, 889-906. gnaccolini, m. (1968) : s uli' origine del" conglomerato pseudocretaceo" di vernasso (cividale del friuli). riv. ital. paleont., 74/4, 1233-1254. hampton, m.a. (1972): the role of subaqueous de bris flow in generating turbidity currents.jour. sed. petrol., 42, 775-793. haq, b.u., hardebol, j. & v all, p.r. (1987) :chro­ nology of fluctuating sea levels since the trias­ sic.science, 235, 1156-1167. hersey, b. (1965): sediment loading in the deep sea. geol. soc. am. bull., 76, 1251-1260. hesse, r. (1982): cretaceous-paleogene flysch zone of east alps and carpathians identification and plate tectonic significance of"dormant" and "active" deep-sea trenches in the a..lpine-carpathian arc. -in: legget, j .k. {ed.): trenchforearc geol­ ogy sedimentation and tectonics on modem and ancient active plate margins. geol. sac. lon­ don spec. pub. 10, 471-494. kelling, g. & mullin, p.r. (1975): graded lime­ stone and limestonequartzite coup le ts : possible storm deposits from the maroccan carboniferous. -sed. geol.,13,161-190. kler, j.s. & pilkey, o.h. (1971): the influence of sea level changes oo ~tcaroonal:ernineialogy, toogue of the ocean, bahamas.mar. geol., ll, 189-200. klervelaan, k. (1987): gordo megabed: a pos­ sible seismite in tortonian submarine fan, tabemas basin, province almeria, southeast spain. -sedim. geol., 51, 165-180. krause, ff. & oldersha w, a.e. (1979): submarine carbonate breccia beds depositional model for two­ .. layer, sediment gravity flows from the sel.cwi forma­ tiro (lowercamtrian), :mockenziemountainsnci1hwest territories canada. -can. jour. earth sci., 16, 189-199. kušćer, d., grad, k., nosan, a. & ogorelec, 150 tunis, g. & venturini, s. (1989) : geologia dei colli di scrio, dolegnae ruttars (friuli orientale): p-ecisazioni sulla stratigrafia e sul significato paleoambientale del flysch di cormons.gortania,ll, 5-24. vail,pr.,mitchum,r.m,jr.,todd,r.g.,widmier, j.m., 1hompson, s. iii, sangree, j .b., bubb, jn. & har1field, w.g. (1977): seismic stratig­ raphy and global cwmges of sea level. -in: payton, c.e. (ed.): seismic stratigraphyapplication to hydro­ carbon e'q)loration. a.a.p.g. memoir, 2q, 49-212. v all, pr (1987): s~ismic stl'atigraphy interpretationusing sequence stratigraphy.in: bally, a.w. (ed.): atlas of seismic stratigraphy.a.a.p.g. studies in geology, 27, l, 1-10. van anđel, t. &komar,p.d. (1969): pondedsedirnents ofthemid-atlanticridgebetween221 and23° north geologia croatica 45 latitude.geol. soc. am. bull., 80, 1163-1190. venturini, s. & tunis, g. (1991): segnalazione di depositi miocenici nella v al tremugna e presso osoppo (friuli).atti tic. sc. terra, 34, 39-42. venturini, s. & tunis, g. (in print): nuovi dati strati grafici, paleoambientali e tettonici sul flysch di cormons (friuli orientale),gortania, udine. venzo, g.a. & brambati, a. (1969): prime osservazioni sedimentologiche sul flysch friulano. -st. trent. sc. nat. sez. a; 46/1, 3-10. yose, l.a. & heller, p.l. (1989): sea-level con­ troj of mixedcarbonate siliciclastic, gravity-flow deposition lower part of the keeler canyon formation (pennsylvanian), southeastern cali­ fornia,geol. soc. am. bull., 101,427-439. manuscript received march, 31.1992. revised manuscript accepted july, 27.1992. 01-velic.indd 1 � ab stra ct a small glacier of cirque-valley type existed during the late pleistocene würm glacial in the tudorevo and mirovo karst valleys of northern velebit. its source was in tudorevo, and it moved through dundović mirovo and bilensko mirovo to baričević dolac, shaping u-valleys around 4 km in length. after melting, glacial deposits remained, composed of chaotic and unsorted till, composed of carbonate sand, debris and sub-rounded clasts, cobbles and blocks of predominantly middle jurassic and subordinately lower jurassic carbonate rocks. in dundović mirovo and bilensko mirovo, where the largest masses of glacial deposits occur, terminal and recessional moraines can be found over the ground moraine, as well as some other features, mostly drumlins (drumlin fi eld), eskers, erratic blocks, kettle holes and striations. some erratics have been transported for more than 4 km from their primary outcrops, e.g. clasts of lower jurassic toarcian spotty limestone. a terminal moraine was deposited between bilensko mirovo and baričević dolac, perpendicular to the glaciated u-valley and it forms the bilo hill, the northern and southern foothills of which are composed partly of glaciofl uvial deposits. between tudorevo and mirovo, a recessional moraine occurs above the ground moraine. the glacier was subject to polyphase melting and freezing, and the youngest freezing events may be related to cirques in tudorevo. during melting events, glacier lakes are supposed to have existed, initially in the baričević dolac, later in mirovo area and fi nally in tudorevo. these discharged into the karst underground by percolation through till and by erosion to the karstifi ed underlying middle jurassic carbonates. keywords: tudorevo–mirovo glacier, till, moraines, drumlins, esker, kettle holes, erratics, glaciolacustrine deposits, glaciofl uvial deposits, late pleistocene, northern velebit, croatia sedimentary bodies, forms and occurrences in the tudorevo and mirovo glacial deposits of northern velebit (croatia) � josipa velić1, ivo velić2 and dubravka kljajo3 1faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, 10000 zagreb, croatia; (jvelic@rgn.hr) 2croatian geological survey, sachsova 2, 10000 zagreb, croatia; (ivelic@hgi-cgs.hr) 3northern velebit national park, krasno b.b., 53274 krasno, croatia; (geolog@np-sjeverni-velebit.hr) doi: 104154/gc.2011.01 geologia croatica 64/1 1–16 25 figs. zagreb 2011 geologia croaticageologia croatica 1. introduction although discussions on glaciation in velebit mt. were led (almost throughout the entire 20th century) by mostly geomor phologists, glacial deposits have been described for the fi rst time at velebit mt. by a geologist. the fi rst description was made in southern velebit, where at oglavinovac, javornik, ribnička vrata and rujno localities nikler (1973) described the boundaries of glaciers, as well as moraine at ruj no. that confi rmed the opinion of former geoscientists (e.g. hranilović, 1901; gavazzi, 1903a, b; schu bert, 1909) on pleistocene glaciations in croatian dinari des. geologia croatica 64/1 geologia croatica 2 the ribnik–rujno glacier existed in the area between 1300 and 1400 m a.s.l., and descended all the way to 920 m a.s.l. (nikler, 1973), indicating signifi cant spreading of pleistocene glaciation at velebit mt. this was confi rmed by later investigations, e.g. belij (1985) who reported on the glacial relief of southern velebit, and illustrated its glaciated apical part from southern velebit kozjak in the southwest, to dušice in the southeast. there are also suggestions that middle pleistocene moraines may be found at the coast in novigradsko more (marjanac et al., 1990). bognar et al. (1991, 1997) have determined that northern and central velebit were glaciated at heights above 1300 m a.s.l. bognar et al. (1991) have, in their description of morphological indicators of glaciations in the northern velebit area, including exaggerated? morphological elements and accumulated deposits, also covered the study area of tudorevo and mirovo, where they described glacial deposits of the late pleistocene alan glacier. however, most of the cited authors investigated and described velebit mt. glaciations from the geomorphological point of view. only nikler (1973) briefl y mentioned the composition and origin of glacial deposits. during investigations for the geological guide-book of the northern velebit national park (velić & velić, 2009), many features that have not previously been reported in croatian geological literature have been found in tills of the tudorevo and mirovo. in the guide-book, glacial deposits were marked for the fi rst time on the geological map of the area. the main goal of the investigation presented here was to determine the basic geological properties of the area characterized by glacial deposition, e.g. the stratigraphy of bedrocks and clasts within the til, as well as the shapes of glacial sedimentary bodies. on the basis of this investigation it was possible to estimate the volume, length and orientation of glacier movements. investigation of the würmian and recent climate, and their correlation, together with the infl uences of postglacial corrosion, etc. were beyond the scope of the investigation. tudorevo (approximately 2 km long), and mirovo (1.5 km long), are karst valleys in northern velebit (fig. 1), located between 1300 and 1450 m a.s.l. in the higher part they are wider, approximately 1 km. mirovo is composed of two smaller valleys, dundović mirovo in the ne and bilensko mirovo in the sw (fig. 1). 2. lithology of the glacial deposits three lithofacies units have been defi ned within the glacial deposits of tudorevo and mirovo: till, glaciofl uvial deposits and glaciolacustrine sands and clays. till is the most common, and may be found in all parts of the study area, while glaciofl uvial deposits are observed in the foothills of the bilo terminal moraine, together with relics of glaciolacustrine deposits assumed in tudorevo and mirovo. 2.1. till tills have been widespread in central and southern parts of tudorevo, in dundović mirovo, bilensko mirovo and at bilo hill. some tills can also be found in the western part of the bilenski padež. till represents loose clastic sediment of highly variable grain size distribution, because it is completely chaotic and unsorted (figs. 2, 4, 10, 16, 19, 21 and 22). it is composed of debris and clasts of carbonate rocks over which, and along which, the glacier moved. clast sizes vary from millimetre, centimetre, and decimetre to metric dimensions i.e. from coarse sands, gravels, cobbles to boulders and blocks. they are mostly poorly rounded, and some show preserved striation formed by friction with ice or with other rock clasts. clast size measurements used for the statistical analysis showed their great variability, so in sampling site ss–1 within a thickness of 1 metre 60% of clasts were below 10 cm, and 40% of 10–25 cm in size. in ss–2, ss–3 and ss–4 the percentage of clasts below 10 cm was about 30%. to illustrate this, data from a till in the top layer of a recessional moraine (rm, ss–1; fig. 3) between the tudorevo and dundović mirovo and in drumlin till (d–13, ss–4; fig. 3) in the bilensko mirovo are presented. fi gu re 1: location map showing the distribution of the tudorevo–mirovo glacier (light greyish) and direction of its movement (gray). velić, j. et al.: sedimentary bodies, forms and occurrences in the tudorevo and mirovo glacial deposits of northern velebit (croatia) geologia croatica 3 sam pling site–1(ss–1) geographic location: recessional moraine on the ridge between tudorevo and mirovo, north of the alan road, orientation 130–310° (fig. 3). moraine dimensions: length 143 m, width 61 m. description: till of the recessional moraine (rm) mainly over lies till of the ground moraine (gm) and drumlin till (d–1; fig. 3), the eastern part overlies thick middle jurassic limestone layers dipping 266/30 (fig. 4). striation oriented 145–325° is visible. till is composed of debris, smaller clasts, cobbles, boulders and blocks of aalenian–bajocian limestones, mostly mudstones, interspersed with interbeds of oncoids up to 1 cm in diameter and lenses of intraclastic wackestones with rounded intraclasts. clasts of toarcian bio turbated spotty limestones rarely occur, while clasts of ty pical fi ne-crystalline toarcian brown dolomite are common. samples from ss–1 trench clasts are mostly cobbles (size in cm and age): 23x23x17, ab; 11x10x8, ab; 20x20x10, ab; 11x9x6,5, ab; 9x12x5, to, dol; 9x10x4, to; 19x24x12, ab; 9x10x4, to; 14x13x10, ab, dol; 13x15x5, ab; 12x12x8, ab; 12x8x7, ab; 12,5x10x6, ab; 10x13x9, ab; 10x18x7, ab;13x12x16, ab; 17x14x15, to; 11x20x9, ab; 25x10x17, ab; 12x17x10, q; 9x8x6, ab; 6x10x7, ab; 9x10x4,5, ab; 11,5x10x4, ab; 10,5x10x5,5, ab; 17x9x10, ab; 15x16x15, to; 23x11x12, ab; 20x13x19, ab; 9x13x10, ab.; 11x10x8, ab; 20x17x10, ab; 11x12x8, ab; 11x11x7, ab; 15x16x15, to; 18x14x11, ab; 14x15x10, ab; 20x16x7, to; 9x24x12, ab; 15x14x7, ab; 7x13x6, b; 15x11x11, ab; 7,5x13x8, ab; 7x10x8, ab; 21x15x12, ab; 13x12x9, ab; (legend: to – toarcian; a – aalenian; b – bajocian; q – quaternary, calcite; dol – dolomite) the remaining 60% of the total excavated mass are clasts of smaller dimensions in the ranges from 8x9x3 cm to 0.7x1x3 cm and smaller. sampling site–4 (ss–4) geographic location: drumlin d–13 in the southern part of the bilensko mirovo (figs. 3, 8, 20 and 23). drumlin dimensions: length 71 m along the 100–280° orientation, width 64.50 m (ne–sw). description: drumlin d–13 overlies older drumlin d–12. till is composed of unsorted, poorly rounded clasts of mm to dm size. only one erratic block has been noticed on top of the drumlin. predominant clasts are of lower jurassic limestones, others are aalenian–bajocian in age. among the identifi ed clasts are those of lithiotid, brachiopod and dark muddy limestones of pliensbachian age, as well as spotty limestones and dolomites of toarcian age. aalenian–bajocian limestone clasts are gray to dark gray mudstones. samples were taken from ss–4 trench at the depths from 50 cm to 90 cm. clasts from the trench are mostly cobbles, rarely boulders (size in cm and age): 15x25x30, prob. ab; 12x13x8, to; 14x9x8, p; 30x24, prob. ab; 13x10x6, p; 10x7.5x3, p; 17x7x6, p; 15x6x5, ab; 10x12x6, ab; 15x12x9, to; 16x10x9 p; 20x13x7, p; 14x10x5, prob. ab; 10x5.5x3, p; 9x6.5x4, p; 13x7x5, to. (legend: p – pliensbachian; to – toarcian; a – aalenian; b – bajocian) smaller clasts (gravels to pebbles) of sizes from 3x2.5x1, to 0.5x0.5x0.4 comprise 25–30 wt. % of the excavated material. for the abovementioned clasts which were not taken for granulometric analysis, three values of their size were measured – the largest, medium and minimum. parameters needed for the determination of their shape were also calculated (after zingg, 1935). nearly 50% of clasts have a discoid shape (in three trenches – ss–1, ss–2 and ss–3) or spheroidal shape (trench ss–4). according to their stratigraphic origin, clasts of middle jurassic carbonates predominate, which is understandable considering that the glacial ‘u’ valley is mostly cut into these deposits. they comprise about 85–90% of the till in the bilensko mirovo, and 40–50% in northern tudorevo. remaining clasts are derived from lower jurassic rocks: pliensbachian lithiotis limestones and toarcian spotty limestones. an interesting situation has been noticed in the trench ss–4 where it was determined that the total mass of till clasts larger than 10 cm is 70%, and among them 70% of the clasts are derived from lower jurassic deposits of eastern part of dundović mirovo (fig. 3). fi gu re 2: chaotic and unsorted till of recessional moraine cropping out on the alan road, northern slope of dundović mirovo. geologia croatica 64/1 geologia croatica 4 fi gu re 3: geological sketch-map of the tudorevo–mirovo area showing the distribution of the glacial deposits with main sedimentary bodies and stratigraphic age of their basement and neighbouring rocks. legend: j1 3 – pliensbachian lithiotis limestones; j1 4 – toarcian bioturbated spotty limestones and dolomites; j2 1,2 – aalenian–bajocian limestones and dolomites; j2 3 – bathonian limestones; gm – ground moraine; tm – terminal moraine; rm – recessional moraine; d–1 to d–13 – drumlins; e–1, e–2 – eskers; k–1 to k–9 – kettle holes; gl – glaciolacustrine deposits; gfl – glaciofl uvial deposits; ss–1 to ss–6 – sampling sites; a–b – geological profi le. velić, j. et al.: sedimentary bodies, forms and occurrences in the tudorevo and mirovo glacial deposits of northern velebit (croatia) geologia croatica 5 besides these carbonate clasts, the till contains small amounts of carbonate silt and clay. granulometric analysis (fig. 5) was performed on eight samples from which, as mentioned above, large clasts were removed. the following values/coeffi cients were obtained: – median (md) mean grain size is 18–32 mm; – sor ting (so) all samples were poorly sorted, which is one of the fundamental features of till; – the skewness coeffi cient (sk) in relation to the median larger grains prevail in all samples except in sample ss–3 from 80–90 cm depth, and all samples are designated as gravel. 2.2. glaciofl uvial deposits glaciofl uvial deposits have been determined in the lower parts of the bilo terminal moraine – in the northern part towards bilensko mirovo and in the southern foothills in baričević dolac (figs. 3, 6 and 7). they are composed of material redeposited from the till. generally, glaciofl uvial deposits are composed of subrounded clasts and pebbles which are smaller and better sorted than those found in till (fig. 6). they were formed by erosion of glacial deposits, in which erosional channels can be found at present in both sides of the terminal moraine, and depositional fans have also been found in the baričević dolac (figs. 3 and 7). it is possible that glaciofl uvial deposits could also be found in some parts of the tudorevo and mirovo. in neighbouring areas they have been found in the vicinity of a mountaineering hut at alan, and also 2 km west in the dundović pod (mamužić et al., 1969). 2.3. glaciolacustrine deposits it is assumed that sand and clay deposits may represent the relics of glacial lakes which were formed during glacier melting. such conditions may have existed in the lowermost parts of tudorevo, dundović and bilensko mirovo, as well as on both sides of the bilo terminal moraine in bilensko mirovo and baričević dolac. in all these localities glacial deposits are covered by humus and dense mountain grass vegetation, and are only sporadically exposed. however, some outcrops, especially on the northern and southern slopes of bilo hill – indicate the existence of probably shortlived small lakes. these heavily vegetated areas are characterized by temporary shallow streams (fig. 7) and aband o ned gardens, indicating probably thicker humus and un derlying deposits. such underlying deposits have been investigated by digging approximately 1 m deep trenches, in which silt –clayey deposits with some sand have been found. the thickness and sediment type indicate probable deposition from stagnant water – shallow lakes and swamps, formed in the last phase of glacier melting. fi gu re 4: geological boundary and geomorphological contrast between middle jurassic (aalenian –bajocian) carbonate bedrock (right) and till (left); alan road. fi gu re 5: granulometric diagram of till from sampling sites ss–1 to ss–4 (for location see fig. 3) geologia croatica 64/1 geologia croatica 6 3. sedimentary bodies and forms of the glacial deposits the erosive action and melting of the tudorevo–mirovo glacier resulted in formation of glacial deposits of varied morphology, including drumlins, eskers, kettles and erratic blocks, as well as ground moraine, terminal moraine and recessional moraine, including some specifi c structures including striations. 3.1. drumlins drumlins (d) occur from the ridge between the tudorevo and dundović mirovo to the southwest part of bilensko mirovo (figs. 3, 9 and 20). in this area of glacial deposits, drumlins are the most common and most numerous forms, so the area of mirovo may be called a drumlin fi eld. drumlins are especially well morphologically expressed at the moraine ridge on the western slope of the dundović mirovo as well as in bilensko mirovo (figs. 8 and 9). according to their dimensions these are small drumlins, since their average length is below 100 m, width 25–65 m, and height 5–15 m (see in bennett & glasser, 2009). the largest drumlins are observed at the pass between dundović and bilensko mirovo – approximately 250x60 m in size (fig. 3, drumlins d–5 and d–8). lithological composition of the drumlin till was described in the previous section. it is interesting that the till, is in all forms, moraines, drumlins and eskers, of uniform lithology, composed of clasts, boulders and blocks of jurassic carbonates. 3.2. eskers two eskers (e) occur; a larger one on the western slopes of the dundović mirovo (e–1; figs. 3, 10a, 10b and 23), and a smaller one in bilensko mirovo (e–2; figs. 3 and 20). e–1 is separated from the underlying moraines towards the west by a narrow gully (fig. 10a). its orientation is nnw–sse (340–160°). it is 117 m long and on average, about 30 m wide. the highest elevation of the esker is 1337 m a.s.l., measured at its top, and the lowest is 1319 m a.s.l. at its terminus in the dundović mirovo, where it ends abruptly by the steep slope (fig. 10a). the lithological composition of till in the esker is the same as in the previously described drumlins. in the terminal frontal part, several erratic blocks have been observed (fig. 16). clasts are mostly composed of older middle jurassic limestones (aalenian–bajocian), but there are some clasts of spotty limestones and dolomite of the lower jurassic (toarcian). 3.3. kettle holes kettle holes or kettles (k) occur in several places in the recessional moraine, i.e. on the tudorevo–mirovo ridge and in mirovo (figs. 3, 9, 11 and 23). here, the lithological comfi gu re 6: glaciofl uvial deposits (gfl in fig. 3) on the northern slope of the terminal moraine (tm in fig. 3); southern part of bilensko mirovo. fi gu re 7: northern slope of the terminal moraine (tm) in the southern part of the bilensko mirovo with glaciofl uvial deposits (gfl) and, probably, glaciolacustrine (gl) deposits below holocene cover. velić, j. et al.: sedimentary bodies, forms and occurrences in the tudorevo and mirovo glacial deposits of northern velebit (croatia) geologia croatica 7 po si tion of till is visible, which is similar to that of the till of surrounding drumlins and ground moraines. their bases are co vered with humus; diameters are 5–20 m and depths 3–7 m. 3.4. cobbles, boulders and erratic blocks boulders and erratic blocks often occur on the surface of glacial deposits, especially along the road from the tudorevo–mirovo pass through mirovo and on the bilo. they are an important source of data for the reconstruction of glacier size and extent of glacier movement. cobbles (ca. 10–30 cm), and boulders (ca. 30–50 cm) are most commonly found in walls and fences of the former arable land and pastures (e. g. figs. 10, 11, 12 and 20). they originated from jurassic carbonates, almost exclusively limestones. their shape is variable – blocky, prismatic, tetrahedral and ellipsoidal, and they are frequently and characteristically poorly rounded (figs. 12 and 13). they are mostly composed of middle jurassic limestones, mainly bajocian and aalenian mudstones, which underlie the glacial deposits. poorly represented, (but very important for the palaeogeographic interpretation), are lower jurassic limestones – lithiotid (figs. 13 and 22) and brachiopod fl oatstones (figs. 14 and 22) of pliensbachian, and typical, unevenly dolomitized spotty limestones of toarcian age (figs. 13 and 22). similar to the middle jurassic ones, lower jurassic clasts are also subrounded, but their shape is often platy as a result of their originally thinner bedding. erratic blocks are scattered in and over various parts and forms of glacial deposits. they are most common on drumlins (fig. 15) and eskers (fig. 16), but some also occur in ground and terminal moraines. their dimensions vary from small (35x60x25 cm) to medium (90x60x50 cm) and large (130x96x110 cm). they originate mainly from the middle jurassic mudstones, and less frequently form lower jurassic lithiotis fl oatstones, including the largest erratic block in these sediments found on the top of the terminal moraine on bilo hill (fig. 17). 3.5. striations striations in the form of scratches and shallow grooves (2–8 mm deep) occur at several places in mirovo, and were observed on the clasts, blocks and primary outcrops of aalenian–bajocian limestones (fig. 18). they show the orientation of the local ice drift, not the direction of glacier mo vement. this was observed by measurements at the tudo revo–mirovo pass where scratches are oriented 325–145°, nearly perpendicular to the direction of movement of glaciers, which was towards 190°. similarly, in the western part of the bilensko mirovo scratches are oriented 80–260°, and the movement of the glacier was to the south – 180°. 3.6. ground moraine remains of ground moraine (gm) were observed in tudorevo, dundović and bilensko mirovo (figs. 3, 10a, 19, 20 and 23), where they represent till, underlying drumlins and eskers. lithological composition of ground moraine till is similar to that of drumlins and eskers. in the western part of dundović mirovo in trench ss–3 (fig. 3), the composition of these deposits was investigated and clast sizes measured. till is composed of unsorted, poorly rounded clasts of mm to dm size, rarely even erratic blocks. clasts of older middle jurassic limestones are very common, mostly aalenian–bajocian in age, but there are also, in places even frequent, clasts of lower jurassic lithiotis limestones (with variable amounts of brachiopods) and of spotty limestones and dolomites (figs. 12–14). clasts below 10 cm in size comprise about 30% of the total mass of the ground moraine till. 3.7. terminal moraine terminal moraine (tm) was found on the bilo hill, the ridge between bilensko mirovo and in baričević dolac (figs. 3, 7, 20, 21 and 23). it is a classical example of the terminus and also the frontal moraine of a valley type glacier, where moraine was deposited transverse to the narrow u-valley (figs. 3, 20 and 21), which is only some 350 m wide. till of the terminal moraine on bilo hill is lithologically similar to other parts of such sediments in tudorevo and mifi gu re 8: drumlin (d–13 in figs. 3 and 23) in bilensko mirovo. fi gu re 9: recessional moraine (rm) and drumlin fi eld (drumlins d–1 to d–4 and kettle holes k–7 to k–8 in figs. 3 and 23) in dundović mirovo. geologia croatica 64/1 geologia croatica 8 rovo, since it is unsorted, chaotic sediment composed of clasts, boulders and blocks of jurassic carbonates mixed with similar mm-sized debris and carbonate silt. clasts are slightly rounded, and mostly originate from the surrounding middle jurassic limestones and partly of the lower jurassic limestone and dolomite (fig. 22). particularly notable, as already mentioned, is an erratic block of pliensbachian lithiotis limestone, found at the top of bilo hill, i.e. at the highest part of the terminal moraine (fig. 17). the thickness of terminal moraine till is estimated at mo re than 100 m, since only hypsometric difference from the base to the top of the moraine, on the southern slope, is mo re than 80 m. fi gu re 10: esker (e–1 in figs. 3 and 23) in dundović mirovo: 10a – norththward view (gm = ground morraine); 10b – southward view b) a) 3.8. recessional moraine recessional moraine (rm) was determined on the ridge between tudorevo and mirovo, above the alan road. its lithological characteristics and dimensions are described in the description of the ss–1 trench. this is probably the youngest form in the glacial deposits of the tudorevo–mirovo glacier as testifi ed by its superposition, since it lies on an older drumlin and ground moraine. bognar et al. (1991) already stated that this is moraine, considering it as the younger frontal moraine of up to 100 m height, up to the base of bilensko mirovo, so it also includes the drumlin fi eld in dundović mirovo. however, all glacial deposits below the recessional moraine, i.e. south of the alan road in dundović and bilensko mirovo, belong to the ground moraine and drumlin fi eld (figs. 3, 9 and 23). 4. geological characteristics of the tudorevo–mirovo glacier area according to the geological and geomorphological characteristics of the tudorevo and mirovo karst valleys, and the recent position of glacial deposits, it is possible to reconstruct the size and spread of the glacier which represented their source. the most important factors for such a reconstruction are geological ones, especially the geological composition of rocks underlying glacial deposits and rocks forming the fl anks of the valleys through which the glacier was moving, as well as the stratigraphic composition of clasts within glacial deposits. 4.1. geological composition of glacial deposits footwall glacial deposits of tudorevo and mirovo mostly overlie middle jurassic carbonate rocks (velić & velić, 2009; figs. 3 and 23). only in the far eastern part of the dundović mirovo and the northern part of tudorevo, do glacial deposits overlie lower jurassic carbonates. boundaries between the underlying rocks and glacial deposits are clearly visible, both lithologically and morphologically (fig. 3). limestones are karstifi ed solid and bedded rocks, which provide strong relief, while glacial and periglacial deposits, mostly non-lithifi ed till, form gentle relief morphologies, and are mostly covered by mountain grasses (e.g. figs. 4 and 20). 4.1.1. lower jurassic carbonates lower jurassic deposits occur in the immediate vicinity or below glacial deposits in the eastern part of the dundović mirovo and northern part of tudorevo. they are represented by two typical lower jurassic lithostratigraphic units: lithiotis limestones and spotty limestones. lithiotis limestones crop out in the far eastern part of dundović mirovo in a gully which ascends towards the veliki alan pass in the ese. towards the north they are in tectonic contact with spotty limestones, and towards the sw, velić, j. et al.: sedimentary bodies, forms and occurrences in the tudorevo and mirovo glacial deposits of northern velebit (croatia) geologia croatica 9 i.e. ne–sw and n–s (figs. 1 and 3). therefore glacial deposits mostly overlie middle jurassic rocks – aalenian–bajocian in tudorevo and at bilo hill, aalenian–bajocian and bathonian limestones. although these rocks are of a wide stratigraphic range (aalenian–bathonian) they are quite monotonous. middle jurassic rocks are composed mostly of grey and dark-grey thick-bedded (40–200 cm), in places massive mudstones, with rare beds of skeletal and bioclastic wackestones and packstones, very rarely grainstones, and interbeds of browngreyish late-diagenetic coarse-crystalline dolomites. stratigraphic subdivision is complicated by the monotonous succession of similar facies and relatively poor fossil contents. division of aalenian and bajocian limestones is especially problematic, and this can only be undertaken by very careful sampling and analysis. in the aalenian limestones of the tudorevo and mirovo, the foraminifer bosniella croatica (gušić) was determined, which is in bajocian on the slopes of šošin vrh, they are covered by them in normal superposition (fig. 3). carbonate deposits of this lithostratigraphic unit are well-bedded dark grey, in places even black wackestones, rarely packstones and grainstones alternating with bioclastic fl oatstones and lithiotid and brachiopod coquinas. the most common allochems include pellets, oncolized intraclasts and bioclasts of bivalves, gastropods, brachiopods (which are very frequent in the younger-most part of the lithiotis limestones), foraminifera and calcareous algae. beds are 10–80 cm thick, mostly 40–60 cm. lithiotis limestones are pliensbachian in age – among the index fossils a benthic foraminiferal assemblage including the most important species, orbitopsella praecursor gümbel is especially important in addition to the lithiotid bivalves. spotty limestones underlie glacial deposits at three localities. they form the ne slopes of tudorevo and the eastern part of dundović mirovo, whereas to the ne they are tectonically seized between aalenian limestones (on the northern slopes of the valley) and pliensbachian lithiotis limestones (in the central part of the valley). the biggest outcrop of spotty limestones crops out south of dundović mirovo, where on the northern slope of šošin vrh they normally overlie lithiotis limestones (fig. 3). lithologically they are composed of alternations of dark muddy and fi ne-grained bioturbated and ooid limestones. they are wellto thin-bedded (mostly 20–30 cm), in places thick-bedded (up to 80 cm), and usually appear irregularly thin-bedded if weathered. spotty limestones were deposited during the toarcian in somewhat deeper environments than those of the underlying and overlying deposits. this change was caused by synsedimentary tectonic activity in the peri-mediterranean area and the infl uence of the oceanic anoxic event. 4.1.2. middle jurassic carbonates the strike of the tudorevo and mirovo karst valleys is almost parallel to the strike of the jurassic stratigraphic units, fi gu re 11: kettles (k–4, k–5 in fig. 3) in bilensko mirovo. fi gu re 12: poorly rounded limestone clasts (mostly cobbles), predominantly of aalenian–bajocian age, within a stone wall on the esker in dundović mirovo; hammer length 33 cm. fi gu re 13: boulders of pliensbachian lithio tis limestones (left) and toarcian spotty limestones (right) in ground moraine in bilensko mirovo; hammer length 33 cm. geologia croatica 64/1 geologia croatica 10 limestones accompanied by the foraminifer pseudoeggerella elongata septfontaine and the dasyclad algae selliporella donzellii sartoni & crescenti. bathonian limestones may be more easily recognized, since they contain a rich assemblage of typical bathonian index fossils including paleopfenderina salernitana (sartoni & crescenti), satorina apuliensis fuorcade & chorowicz, orbitammina elliptica (d’archiac), etc. middle jurassic carbonates were deposited in somewhat shallower environments than toarcian spotty limestones, but probably deeper than pliensbachian lithiotis limestones, mostly in spacious, protected lagoons. 4.2. origin and distribution of clasts in till till of the tudorevo, mirovo and bilo is composed of clasts, boulders and blocks of lower jurassic lithiotis limestones of pliensbachian age, and spotty limestones and dolomites of toarcian age, as well as middle jurassic, mostly aalenian and bajocian limestones, which are accompanied by bathonian limestones in the terminal moraine. it is important to stress that these deposits do not contain upper jurassic clasts. figure 24 shows the distribution of clasts according to their stratigraphy. it is obvious that the most common clasts are those originating from aalenian–bajocian carbonates, which is not unsurprising since these rocks compose most of the bedrock beneath the glacial deposits (fig. 3). their compositional proportion may be estimated as from 60% in the northern part of tudorevo to approximately 85% in mirovo. clasts of spotty limestones may be found in till of all glacial deposits, from the northern part of tudorevo to the terminal moraine in baričević dolac. their origin is geologically clear, since spotty limestones represent the bedrock of the sw part of tudorevo and the eastern and southern parts of the dundović mirovo (fig. 3). however, data on the distribution of lithiotis limestones (fig. 24) are especially interesting. they have not been found at tudorevo, only at mirovo and in the terminal moraine of bilo. this information, in addition to the fact that there are no upper jurassic clasts in the investigated till deposits, is very important for the interpretation of glacier movement, which will be discussed in the next section. 5. origin, dimensions and movement of the glacier in order to enable easier understanding of this section it is important to discuss some possible terminological confusion. bognar et al. (1991) described alan glacier with a source area in lubenovac and a terminal moraine in bilensko mirovo. the tudorevo–mirovo glacier described in this paper had its source area in tudorevo and terminal moraine in baričević dolac (fig. 1). it is clear that these are two different names for the same glacier, but with different supposed sources and glacier paths. a new name was proposed here because (i) no evidence was found that the glacier had a connection with lubenovac, and (ii) to enable differentiation of the geological approach in this paper with the geomorphological approach applied by bognar et al. (1991). fi gu re 14: part of a pliensbachian brachiopod fl oatstone cobble in ground moraine of bilensko mirovo; scale 5 cm. fi gu re 15: erratic blocks originated from pliensbachian lithiotis limestones as well as from aalenian–bajocian limestones in drumlin (d–3 in figs. 3 and 23) of dundović mirovo. fi gu re 16: erratic blocks in esker (e–1 in fig. 3; figs. 10 and 23) of dundović mirovo com po sed of aalenian–bajocian limestones; ham mer length 33 cm. velić, j. et al.: sedimentary bodies, forms and occurrences in the tudorevo and mirovo glacial deposits of northern velebit (croatia) geologia croatica 11 concerning the stratigraphy of clasts and boulders, as well as the recent geomorphology of tudorevo and mirovo, it is very probable that the studied glacier was composed of two glacial tongues – the main one, which originated in the cirques of tudorevo and a lateral one which originated in the eastern part of dundović mirovo. both tongues joined into one glacier in the central part of the dundović mirovo. along its way from the source in tudorevo to mirovo and baričević dolac, the glacier eroded the underlying and surrounding rocks, and crushed them into blocks, boulders and clasts, dragging them and transporting them several kilometres from their source. material was crushed and rounded during transport, and phases of thawing resulted in deposition as till in drumlins and eskers, as ground, terminal and recessional moraines. a glacial tongue in the eastern dundović mirovo abraded pliensbachian lithiotis limestones (with frequent brachiopods) and toarcian spotty limestones, and transported their fragments to the dundović mirovo where it united with the main glacial tongue coming from tudorevo. these fragments were transported to the terminal moraine in baričević dolac, a distance of some 2.5 km from the source rocks. 5.1. previous investigations bognar et al. (1991) determined the direction of movement of the glacier from lubenovac towards the southwest to mirovo, which was predisposed by the pre-würmian morphology of this part of velebit. the authors named it as the alan glacier. in addition to the main glacier source in lubenovac large amounts of the ice mass moved by three glaciers, or glacial tongues, towards the southeast into the valley of kosinjski bakovac – one through vranjkova draga, a second through kozjanska draga, and the third through ju rekovačka and begova draga. the authors described the movement of the glacier from veliki lubenovac to tudorevo and over the ridge between tudorevo and mirovo to dundović mirovo and bilensko mirovo where they marked the terminal moraine. however, the terminus of the glacier was still further away, more than 1 km south in baričević dolac. during the latest investigation, presented here, the connection between glacial deposits, i.e. glaciers in lubenovac and tudorevo has not been proven by geological methods. if such a connection existed, i.e. if the glacier originated in lubenovac then clasts of lithiotis limestones should occur, in tudorevo but are missing, since these rocks crop out in the valley between grebalište and vučjak, through which the glacier should have passed. clasts of upper jurassic strata are also missing, and these form lubenovac and the neighbouring area, so should also have been transported to tudorevo, or even to mirovo. on the basis of analysis of the present relief it seems more probable that the glacier was moving from the northern part of tudorevo (approximately 1350 m a.s.l.) towards lubenovac (ca. 1260 m a.s.l.) than vice versa. geological evidence could be discovered by future investigation of the glacial deposits of lubenovac. bognar et al. (1991) indicated that terminal moraine of the alan glacier should be located in the bilensko mirovo, which is a typical drumlin fi eld, although it is located more than 1 km southwards at bilo, between bilensko mirovo and baričević dolac (figs. 3, 20, 21, 22 and 23). fi gu re 17: erratic block originated from pliensbachian lithiotis limestones on the top of the terminal moraine at the bilo hill; hammer length 33 cm. fi gu re 18: striations in bajocian limestones; western slope of bilensko mirovo; scale 5 cm. fi gu re 19: till of ground moraine; western dundović mirovo. geologia croatica 64/1 geologia croatica 12 views presented by bognar et al. (1991) are based solely on geomorphological studies, while geological investigations presented in this paper do not confi rm such glacier movement. in contrast, geological data collected in tills of tudorevo and mirovo did not confi rm any connection with upper jurassic deposits of lubenovac. therefore the studied glacier was named the tudorevo–mirovo glacier. 5.2. origin basic characteristics of the northern velebit valley glaciers were described by bognar et al. (1991). generally, the authors claimed that numerous glacial tongues were directed from the surrounding hills towards the bigger valleys, forming several km-sized glaciers. this statement also describes the tudorevo–mirovo glacier very well. it originated from tudorevo as a combination of cirque-type and valley-type glaciers. today three cirques may be morphologically recognized in tudorevo: northern, central, and southern, which is morphologically the most typical and biggest (fig. 25). glacial tongues from neighbouring hills were moving towards tudorevo, the biggest and hypsometrically lowest valley (southern cirque at ca. 1300 m a.s.l., northern cirque at 1350 m a.s.l.), where they formed three smaller cirque glaciers, which were united into a single glacier by further accumulation of ice. on reaching a thickness of ~100 m and with suffi cient kinetic energy, the glacier moved across the pass south of tudorevo and spilled into dundović mirovo, where it united with a much shorter glacial tongue that originated from the eastern part of the dundović mirovo. in this way, the united glacier, containing a huge ice mass, became a typical valley-type glacier which gouged a typical ‘u’-shaped glacier valley along its path through dundović and bilensko mirovo. 5.3. volume and movement the tudorevo–mirovo glacier was a typical cirque-valley glacier of varying width – from about 250 m at the bottom to probably more than 500 m, and in some places up to 1,000 m in its apical part, as wide as present glacial valleys, e.g. tudorevo, through which it moved. during maximum glaciation, the glacier was about 4 km long, and therefore it was a relatively small, local glacier. at that time it covered tudorevo, dundović mirovo and bilensko mirovo, reaching baričević dolac where it deposited a terminal moraine, the current bilo hill. the length of the transport of this material was determined on the basis of current distance of clasts in glacial deposits from their primary outcrops and beds. the most reliable deposits are clasts, boulders and blocks of lower jurassic lithiotis limestones of pliensbachian age and spotty limestones and dolomites of toarcian age. in order to determine the spreading and movement of the glacier, stratifi gu re 20: terminal moraine (tm) at the bilo hill (back of the photo), ground moraine (gm, with drumlins d–12 and d–13, esker e–2 and kettle holes k–3 to k–5) and karstifi ed carbonate bedrock (of the upper bajocian age) between them; southward view from bilensko mirovo. fi gu re 21: landscape of glacial ‘u’ valley in the dundović and bilensko mirovo; in background terminal moraine (tm) at the bilo hill. fi gu re 22: till of the terminal moraine (sou thern slope of the bilo hill) with clasts, cobbles and boulders of lower jurassic plien sba chian lithiotis limestones including lithiotid fl oatstones (lf ) brachiopod fl oatstones (bf), toarcian bioturbated spotty limestones (sl), and predominantly of middle jurassic limestones; hammer length 33 cm. velić, j. et al.: sedimentary bodies, forms and occurrences in the tudorevo and mirovo glacial deposits of northern velebit (croatia) geologia croatica 13 graphic analysis of more than 2000 clasts of jurassic rocks from tudorevo, mirovo and bilo was performed. dimensions of the studied clasts were from 1 cm to erratic blocks of more than 2 m3. in dundović and bilensko mirovo, clasts were transported from their source rocks for at least 2 km. the most distant ones occur at bilo, including the aforementioned lar ge erratic block (approximately 2 m3 in volume) of pliensbachian lithiotis limestones (fig. 17), which was transported from primary outcrops in the easternmost part of the dundović mirovo (fig. 3). the same locality was the source of pliensbachian lithiotis limestones with frequent brachipods (indicating the younger-most level of this lithostratigraphic unit) for the entire mirovo (fig. 14) and terminal moraine of bilo (fig. 22). transport of toarcian spotty limestones clasts and boulders (figs. 13, 22 and 23) was even longer, up to 4 km, since they could have originated not only from the dundović mirovo, but also from the northern part of the tudorevo (figs. 3 and 24). the origin of the glacier in tudorevo, instead of lubenovac, is confi rmed by analysis of till clasts in tudorevo, but also in mirovo and in the bilo terminal moraine. in till from all the aforementioned localities, no clasts of upper jurassic li mestones have yet been discovered, and lubenovac and neighbouring area north of the bakovac fault are completely com posed of such rocks. in addition, according to recent hy p sometric relationships, in order to start the glacier from lubenovac towards tudorevo, ice in the lubenovac cirque had to reach a thickness between 200 and 300 m. this is supported by the contour lines of recent elevation: the base of the lubenovac is at an altitude of 1255 m a.s.l., and rises towards tudorevo at 1445 m a.s.l., so ice not only must have infi lled the lubenovac cirque but must also have exceeded the height of the ridge, thus gaining kinetic energy to initiate its movement towards tudorevo. a similar situation occurs in tudorevo where the base of the southernmost cirque is at an altitude of 1291 m a.s.l. in or der for the glacier from tudorevo to cross the ridge on its way to mirovo, where present primary layers of the aalenian – bajocian limestones occur at an altitude of 1390 m a.s.l., the thickness of the ice had to be more than 100 m. it was probably even up to 200 m, which is not surprising, be cau se the glacier was also enriched by ice arising from the cir ques of tudorevo, and from the surrounding hills and valleys. the direction of movement of the glacier is indicated by shapes and orientations of the drumlins and eskers, since their long axes are parallel with the direction of movement. in plan view, the narrow end of the drumlin ellipsoid determines the direction of movement of the glaciers, and also in the longitudinal profi le their more gentle slopes. in the tudorevo–mirovo glacier drumlins are best expressed in mirovo. on the northern slopes of dundović mirovo, from alan road to the bottom of the valley, there are several drumlins fi gu re 23: geological profi le baričević dolac–tudorevo (profi le line a–b on fig. 3). legend: j2 1,2 = aalenian–bajocian limestones, sporadically interca lations of latediagenetic dolomite; j2 3 = bathonian limestones; gm = ground morraine, tm = terminal morraine; rm = recessional morraine; d–1 to d–13 = drumlins; e–1 = esker; k–4 = kettle hole; gl = glaciolacustrine deposits; gfl = glaciofl uvial deposits. fi gu re 24: distribution of bedrock clasts (pebbles, cobbles, boulders, blocks) in morraine deposits. legend: 1 = clasts originated from toarcian spotted, bioturbated limestones/dolomites and aalenian–bajocian limestones (in terminal morraine of bathonian limestones too); 2 = clasts originated from pliensbachian lithiotis and brachiopod limestones. geologia croatica 64/1 geologia croatica 14 and one esker which narrows, indicating the direction of movement of the glacier, towards the southwest – direction d = 225° (figs. 1 and 3). this direction deviates from the general orientation of the esker, south–southeast, d = 160°, which is logical, because till of the esker was deposited by streams that fl owed below or within the ice toward the bottom of the dundović mirovo (fig. 3). on the ridge between the dundović and bilensko mirovo, longer axes of the drumlins and therefore the direction of movement are rotated mostly to the southwest, d = 240°, and in bilensko mirovo also to the west–northwest, d = 280° (fig. 3, drumlins d–10 and d–13). these individual differences are due to local topography, which infl uenced the direction of the movement of ice and streams during the deposition of drumlins. from the bilensko mirovo, the main part of the glacier, from which glacial deposits accumulated, moved to the south to baričević dolac. however, it is possible that part of the ice mass moved west across the ridge between bilensko mirovo and the alan valley, and over the buljma ridge (elevation 1400 to 1450 m a.s.l.), but data on this are currently unavailable, because this area has not yet been the subject of a detailed geological survey. the southern end of the bilensko mirovo, where the glacial ‘u’ valley is best expressed (figs. 3, 20 and 21), exposes upper bajocian–lower bathonian carbonates underlying the glacial deposits. going further south, after 250 m, glacial deposits occur again, building up the ridge (bilo hill) be tween bilensko mirovo and baričević dolac (fig. 3). the se are the remnants of the terminal moraine of the glacier. its extreme southern boundary was probably in the baričević dolac (figs. 1, 3 and 23) at an altitude between 1330 and 1290 m a.s.l., because at lower elevations no remnants of glacial deposits have been observed. if these data are compared with the starting point of the glacier in tudorevo, they indicate a maximum length of, approximately 4 km (fig. 1). it is assumed that the tudorevo–mirovo glacier had several phases of melting and re-freezing, as indicated by several factors. in bilensko mirovo, drumlin d–13 (fig. 8) lies obliquely across an older drumlin d–12 (figs. 3 and 20). recessional moraine between the tudorevo and dundović mirovo overlies older ground moraine and drumlin d–1 (figs. 3 and 9). this recessional moraine can be assumed to be not only a stadial moraine but also a a terminal moraine of the tudorevo part of the glacier during a shorter stadial, when in mirovo ice had already completely melted. melting occurred in a direction opposite to the movement of glacier, i.e. from the southwest from bilensko mirovo to the northeast to tudorevo. in the early stages of melting, when ground moraine, drumlins and eskers were created, glacial lakes/marsh were formed on both sides of the terminal moraine, because of the large amounts of water. it was also the time of occurrence of kettle holes which were carved in the till of the ground moraine by ice boulders and blocks in the lowermost part of the glacier. water escaped (due to draining from the lake and erosion of till of the ground moraine) into the underlying karstifi ed middle jurassic carbonates. smaller, decametre-sized fans of glaciofl uvial material were formed by erosion of till of the bilo terminal moraine on the lower part of its slopes (figs. 3, 6 and 7), which was partially deposited within the aforementioned lakes. such glaciofl uvial material may also probably occur in some parts of mirovo and tudorevo. at the same time, the glacier still existed in tudorevo, resulting in accumulation of the recessional moraine deposited at the pass from tudorevo to mirovo. however, warming in the early holocene also melted that part of the glacier, and large amounts of water produced by melting ice eroded the eastern, thinnest part of the recessional moraine in the vicinity of the crossing of the alan road with the road to lubenovac, where the bedrock crops out – the primary outcrops of aalenian–bajocian limestones. the local climate conditions, large amounts of snow precipitation, temperatures below zero for 10 months of the year (bognar et al., 1991 – p. 35, table 2) and suitable relief were the most important factors in the development of a series of glaciers on northern velebit. the tudorevo–mirovo area had all the conditions for the development of a valleytype glacier. these conditions are in part upheld up today, because even with the average annual snow precipitation, large snow drifts form at the pass between tudorevo and mirovo. during the winter months snow freezes, and in the spring thaws slowly so that the alan road is only passable from june. according to bognar et al. (1991) alan’s youngest glacier was of würmian age. that is its most probable age, although geological work on the glacial deposits of tudorevo and mirovo neither confi rmed nor denied this. research in this regard is still pending. 6. conclusions during the younger pleistocene, probably würmian glaciation in the northern velebit several glaciers were formed, among them the tudorevo–mirovo cirque/valley-type glacier. its starting point was in tudorevo and it extended to the southwest through the karst valleys of dundović mirovo and fi gu re 25: landscape of the tudorevo valley (northward view) with three cirques: c-1 (south tudorevo), c-2 (central tudorevo), c-3 (north tudorevo). velić, j. et al.: sedimentary bodies, forms and occurrences in the tudorevo and mirovo glacial deposits of northern velebit (croatia) geologia croatica 15 bilensko mirovo to baričević dolac along a distance of about 4 km. the glacier formed a typical u-shaped valley, with an average width of ~500 m, best expressed today in mirovo. the action and melting of the glacier formed glacial deposits particularly well preserved in tudorevo and mirovo with many typical relief forms. they were deposited over lower and middle jurassic carbonates ranging in age from pliensbachian to older bathonian. glacial deposits are composed of chaotic and unsorted till of heterogeneous particle size, but uniform lithological composition, represented only by the clasts of lower and middle jurassic carbonates, mainly limestones. grain-size is very variable, from sand to various blocks even greater than 2 m3 in volume. middle jurassic clasts make up from about 60% of the total mass of till in ne tudorevo to 85% in mirovo. many forms of moraine have been identifi ed, described and illustrated: ground moraine, terminal moraine and recessional (stadial) moraine, drumlins, eskers, erratic blocks, kettle holes and striation. the area of mirovo, due to the numerous drumlins, represents a drumlin fi eld. recessional mo raine, drumlins, drumlin fi eld, eskers and kettles were recognized and described for the fi rst time in the area of the velebit mt., but also in croatia. orientation of the drumlins, eskers and glacial ‘u’ valleys, as well as the terminal and recessional moraines indicate movement of the glacier from the northeast to the southwest and south, i.e. from the tudorevo through mirovo to baričević dolac. in dundović mirovo, the glacier was accompanied by a smaller glacial tongue, the source of which was in the far eastern part of the dundović mirovo. along its 4 km length from the area composed of bioturbated toarcian spotty limestones in the ne part of tudorevo, the glacier moved mostly through middle jurassic carbonates of the tudorevo and mirovo, as well as through pliensbachian lithiotis limestones of dundović mirovo to its terminus in baričević dolac. it transported clasts, boulders and blocks for several kilometres (longest transport is recorded for clasts of toarcian spotty limestones – 4 km and for pliensbachian lithiotis limestones clasts – more than 2 km). relationships between the sedimentary bodies, such as the position of recessional moraine on older drumlin and ground moraines, or the case that a younger drumlin overlies an older one in bilensko mirovo, indicate multiphase dissolution and refreezing of the tudorevo–mirovo glacier. since the beginning of the fi nal stage of glacier melting, drumlins and eskers were formed on the ground moraine, and within the moraine ice blocks carved kettles. advancing melting and retreat of ice from the mirovo towards tudo revo formed glacial lakes with glaciolacustrine sedimentation on the low permeable ground moraine of mirovo and terminal moraine of bilo. gradual percolation of water from the lakes, and erosion of the underlying sediments of ground moraine to the underlying karstifi ed middle jurassic carbonate rocks caused draining of water and formation of the recent relief of mirovo. at that time, a glacier still existed at tudorevo resulting in a recessional moraine at the pass to mirovo, but this, (similar to the one in mirovo), melted at the very beginning of the holocene. erosion of till, formed glaciofl uvial deposits, and their fans were found in the lower parts of ravines on the slope of the bilo terminal moraine. acknowledgement this work represents part of a multidisciplinary geological investigation that was performed during 2008 and 2009 within four projects – three fi nanced by the ministry of science, education and sports of the republic of croatia entitled ‘stratigraphical and geomathematical researches of petroleum geological systems in croatia’ (project no. 195 -1951293-0237) and ‘microfossil assemblages in carbonate deposits of the karst dinarides’ (project no. 195-19530680242), and basic geological map of the republic of croatia 1:50.000 (181-1811096-1093), and a project fi nanced by the northern velebit national park entitled ‘investigation of moraine sedimentary bodies in the northern velebit national park’. many thanks to irena mrak from university of ljublja na, slovenia and sanja faivre from the university of zag reb, croatia for their very useful objections and suggestions. references belij, s. (1985): glacijalni reljef južnog velebita [glacial relief of southern velebit – in croatian].– geografski glasnik, 47, 71–85. bennett, m.r. & glasser, n.f. (2009): glacial geology. ice sheets and landforms.– wiley-blackwell, 2nd ed., xiii+385 p. bognar, a., faivre, s. & pavelić, j. (1991): tragovi oledbe u sjevernom velebitu [glaciation traces in the northern velebit – in croatian].– geografski glasnik, 53, 27–39. bognar, a., faivre, s. & pavelić, j. (1997): tragovi oledbe u srednjem velebitu [traces of glacial deposits on the central velebit – in croatian].– senjski zbornik, 24, 1–16. gavazzi, a. (1903a): tragovi oledbina na našem kršu.– glasnik hrvatskog naravoslovnog društva, 14, 174–175. gavazzi, a. (1903b): tragovi oledbe na velebitu.– glasnik hrvatskog naravoslovnog društva, 14, p. 459. hranilović, h. (1901): geomorfološki problemi iz hrvatskoga krasa.– glasnik hrvatskog naravoslovnog društva, 13/1–3, 93–133. mamužić, p., milan, a., korolija, b., borović, i. & majcen, ž. (1969): osnovna geološka karta sfrj 1:100.000, list rab, l 33–114 [basic geological map of sfry 1:100000, rab sheet – in croatian].– institut za geološka istraživanja zagreb (1959–1965), savezni geološki zavod beograd. marjanac, t., marjanac, lj. & oreški, e. (1990): glacijalni i periglacijalni sedimenti u novigradskom moru [glacial and periglacial sediments in novigradsko more, northern dalmatia, yugoslavia – in croatian].– geol. vjesnik, 43, 35–42. nikler, l. (1973): nov prilog poznavanju oledbe velebita [ein neuer beitrag zur kenntnis der vereisung im velebit gebirge – in croatian].– geol. vjesnik, 25, 109–112. geologia croatica 64/1 geologia croatica 16 schubert, r. (1909): zur geologie des österreichischen velebit (nebst pälaontologischen anhang).– jahrb. geol. reichsanst., wien, 58/2, 335–386. velić, i. & velić, j. (2009): od morskih plićaka do planine. geološki vodič kroz nacionalni park sjeverni velebit [geological guide through national park northern velebit – in croatian].– national park northern velebit – krasno, 143 p. zingg, t. (1935): beitrag zur schotteranalyse.– schweiz. miner. petrol. mitt., 15, 39–140. manuscript received march 29, 2010 revised manuscript accepted december 28, 2010 available online february 22, 2011 dragicevic & velic.indd 1. introduction the evolution of the northern margin of the adriatic carbonate platform (adcp) can be reconstructed for the period between the early jurassic and the early palaeogene. its recent strike is nw–se (dragičević & velić, 1994) and can be followed from the slovenian basin (near tolmin in slovenia) extending all the way to the krasta–cukali–budva trough in northern albania the northeastern margin of the adriatic carbonate platform ivan dragičević1 and ivo velić2 and southern montenegro (fig. 1). this zone extends in a nw–se direction through central slovenia (buser, 1987; turnšek, 1997; dozet & šribar, 1998a) in the direction of the žumberak region and the surroundings of karlovac in croatia (bukovac et al., 1974, 1984; šparica, 1981; jelaska, 1987). from karlovac, it extends in a southerly direction, through the kordun area, towards slunj and then towards the south-east in nw bosnia, in the environs of bihać, bosanska krupa and sanski most, and towards banjaluka (šparica, 1981; jelaska, 1987). from there, the margin extends in a south-eastern direction, through central bosnia towards jajce and kupres (dragičević, 1987; dragičević & velić, 1994), and passes close to prozor into northern herzegovina, where it can be followed north and east of mt. prenj, or south of the upstream part of the river neretva (sofilj & živanović, 1979; mojičević & tomić, 1982a), and finally east of nevesinje all the way to gacko (mojičević & laušević, 1969; mirković, 1980). in montenegro, the margin strikes between mt. golija and mt. durmitor (mirković & vujisić, 1989) and in a se direction towards the maglić and prokletije mts. (kalezić et al., 1973; đokić et al., 1973) where it passes into the albanian alps in northern albania, approximately along the skadar–peć line, i.e. to the krasta–cukali–budva trough in the se. the total length of the northern or north-eastern margin of the platform is over 700 km (velić et al., 2002a), but it should be stressed in the beginning, that the palaeogeographic continuity of both the adriatic carbonate platform and its northern margin can also be recognised over a broader region than described above. it is just a part of the large shallow marine platform system of tethys (dercourt et al., 1993) that extends from the region of furlania in the southern calcareous alps (in the nw) towards the se through the karst dinarides, albanides and helenides all the way to the eastern taurides. the recent position of the margin is marked at the surface by the maximal extension of mesozoic shallow-marine carbonate rocks of platform characteristics in a direction ne of the contact with the slope and/or deep-marine, basinal sediments, mostly represented by clastics, that are usually called the “flysch”. in the present, complex geological structure, the northern margin of adcp is best observed along the strike from the žumberak region in croatia to central bosnia (fig. 1). data acquired by field study of the platform margin in geologia croatica 55/2 185–232 33 figs. zagreb 2002 key words: adriatic carbonate platform (adcp), external dinarides, northeastern margin, depositional systems, palaeogeography, geodynamic evolution, jurassic, cretaceous, croatia, bosnia and herzegovina, slovenia, montenegro. 1 university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, hr-10000 zagreb, croatia; e-mail: idragic@rgn.hr 2 institute of geology, sachsova 2, hr-10000 zagreb, croatia. abstract at the end of pliensbachian or during the toarcian, several carbonate platforms were individualised by extensional tectonics in southern tethys, of which the adriatic carbonate platform is one. as a unique and isolated shallow marine depositional system it existed until the end of the cretaceous. in the late lias, the platform margins and slopes were formed by the individualisation processes. due to the presence of younger sedimentary cover and tectonic disruption from the early jurassic until the present, only small parts of the north-eastern margin and its slope are exposed at the surface. during the entire “life-span” of the platform, its ne margin and slope retained more or less the same palaeogeographic position – from western to south-eastern slovenia, through the central part of croatia, western and central bosnia, northern herzegovina and montenegro all the way to northern albania. the region between žumberak in croatia and central bosnia was the most dynamic part of the platform margin during the jurassic and cretaceous. shifts of the marginal and slope facies were recorded in žumberak, where the platform area was progressively reduced during the period from the lias to the malm. at the same time, the platform was extended in central bosnia and montenegro. a more pronounced reduction of the platform in cenomanian times marked the beginning of the process of disintegration. the end of the cretaceous was also the end of the “life” of the adriatic carbonate platform. it mostly became emergent, and the renewed shallow marine carbonate depositional environments in the eocene were short-lived and lacked the previous platform characteristics, as well as the regional distribution and integrity. 186 geologia croatica 55/2 187dragičević & velić: the northeastern margin of the adriatic carbonate platform this region offers a reliable starting point for interpretation of the jurassic and cretaceous evolution of the margin. the available published sources will also be fully utilised to reconstruct the general palaeogeographic relations in the other parts of the platform margin, both in slovenia, south-eastern bosnia and herzegovina and in montenegro. since there are not so many new papers on this subject, several sheets of the basic geological map (scale 1:100,000) and their accompanying notes of explanation were used as fundamental references. through geodynamic evolution during the jurassic and cretaceous the adcp and its ne margin changed in (palaeo)geographical orientation from nearly meridional, i.e. nne–ssw strike (dercourt, 1993; stampfli & mosar, 1999) in the early jurassic, to a nnw–sse orientation in the late cretaceous. recently it mostly corresponds to the dinaric strike (nw–se) in croatia, bosnia and herzegovina and montenegro, but in slovenia it is oriented w–e. since the results presented in this paper were mostly obtained from investigation in croatia and bosnia and herzegovina its recent position as the ne platform margin has been preferred and accepted. 2. recent geological setting the complex recent geological structure is a consequence of the post-platform structural-tectonic changes that had already started at the end of cretaceous and intensified through the early tertiary. they culminated in the neogene and quaternary and the original geological relationships from the time when the carbonate platform existed are now partly overprinted and masked by fault tectonics. the late cretaceous–tertiary deposition of the carbonate–clastic sediments covered a substantial part of older carbonate sequences of the platform margin and slope which are, therefore, both in a stratigraphical and geographical sense, only partially available for field investigations. besides, it is necessary to take into consideration the geodynamics of the platform margin i.e. its migration, uplift, erosion, and fig. 1 recent boundaries of the adriatic carbonate platform deposits and geographic position of the geological columns, profiles and outcrops within the investigated area of the northeastern platform margin: 1) žumberak–samobor mts.; 2) ozalj; 3) dubravčani; 4) martinšćak–barilović; 5) budački gornji; 6) cetingrad; 7) otoka (bosanska krupa); 8) subotica (bronzani majdan); 9) jagare (banjaluka); 10) kotor varoš; 11) kotor varoš–skender vakuf; 12) paunovići (skender vakuf); 13) vidovo vrelo; 14) trijebovo (mrkonjić grad); 15) liskovica–bešpelj; 16) seoci (jajce); 17) ravanac; 18) bila; 19) guča gora; 20) kaonik; 21) čardak livade; 22) strojice (janj); 23) kupres; 24) karlovac. n 186 geologia croatica 55/2 187dragičević & velić: the northeastern margin of the adriatic carbonate platform drowning mostly as consequences of permanent tectonic activity during the jurassic and cretaceous. these are the reasons why there are no localities or sections where the sedimentary stratigraphic sequences from the early jurassic to the end of cretaceous could be followed continuously and in their entirety. also, there is no continuity of the described units or stratigraphic sequences along the strike of the recent geographic position of the platform margin. facies of the platform margin were not uniform throughout the entire time span of its existence (early jurassic to the end of cretaceous). they are very rarely recognisable in the early and middle jurassic successions and most extensively distributed and best determined in the late jurassic strata. the early cretaceous sections are also seldom preserved – there are only traces from the barremian, early aptian and cenomanian and relatively frequent occurrences of santonian, campanian and maastrichtian deposits (fig. 3). generally, jurassic and cretaceous shallow water carbonates of the platform margin are to a large extent covered by clastic sediments, i.e. by campanian–maastrichtian–palaeocene flysch. this reduces the investigation of the ne platform margin mostly to the deposits cropping out beneath this flysch, and to the area of contact between the stratigraphically older carbonate platform sequences and slope-to-basin sequences in localities where they are not covered with the aforementioned flysch deposits. 2.1. geological columns and cross-sections at locations through the investigated area with comparatively well exposed sections along the margin of the adriatic carbonate platform, several geological columns were measured and analysed in detail. generalised geological cross-sections were surveyed in areas where sequences are weakly exposed. some interesting locations were regretfully unreachable for field investigation. these parts are complemented by the results of work of previous researchers. descriptions are grouped geographically, from nw to se (i.e. from žumberak to central bosnia). 2.1.1. žumberak–samobor mts. jurassic deposits in žumberak and in the samobor mts. were described by radoičić (1966), gušić & babić (1970), babić (1973, 1976), šikić & basch (1975), pleničar et al. (1976), šikić et al. (1978, 1979), bukovac & sokač (1989) and bucković et al. (2001). based on the investigations of these authors and our own results, facies characteristics and interpretation of depositional environments are shown in geological column (fig. 1, location 1; fig. 2). shallow marine lower lias and lowermost middle lias at the very margin of the platform, are represented by an alternation of mudstones, fossiliferous wackestones and pelletal packstones with bioclastic and ooid grainstones and late diagenetic dolomites, containing calcareous algae palaeodasycladus mediterraneus (pia), sestrosphaera liasina pia and benthic foraminifera lituosepta recoarensis (cati). they are overlain by slope limestones of the late lias: mud-supported mostly fossiliferous wackestones with lithoclasts of platform limestones, rarely containing ooids, involutina liassica (jones), lagenids, nodosarids and other organisms of the slope biotope. lias slope deposits are followed by limestones with filaments, spicules, globigerinids, saccocomas and other pelagic organisms, which also occasionally contain platform benthic foraminifera (trocholinas). laterally, there are bodies of slope breccias (?debrites) wherein the fragments of all the previously mentioned limestone types were found. in this way the described sequence of slope sediments would correspond to the time span from the middle jurassic to the pre-tithonian part of the late jurassic. the final part of the jurassic sequence of žumberak and the samobor mts. is mostly composed of basinal “calpionella limestones” of tithonian, berriasian and valanginian age that were thoroughly investigated by babić (1973). on the platform margin a coral–hydrozoan barrier reef existed throughout the uppermost oxfordian to the lowermost berriasian. 2.1.2. ozalj the platform margin and slope-to-basin facies ranging from early jurassic to uppermost cretaceous age were investigated in the karlovac area (fig. 1, locations 2 to 5). in the ozalj locality (fig 1, location 2; fig. 3) oolithic grainstones prograde over upper jurassic barrier coral–hydrozoan reefs and they are mostly covered by berriasian mudstones. laterally, the slope breccias, calpionellid and fossiliferous mudstones (with calpionella alpina lorenz and other tintinnids) of late tithonian and berriasian age were deposited. together with remains of pelagic organisms, they contain carbonate grains (bioclasts and ooids) derived from the platform margin and shallows. these deposits are unconformably overlain by santonian–campanian breccias and conglomerates – basal part of the campanian–maastrichtian flysch. to the north and northeast (in žumberak), babić (1974) described slope and basinal sediments of hauterivian–cenomanian age overlying older deposits of different ages ranging from the late triassic to valanginian. the author interpreted their position as displacements of the platform margin including the broadening of the basin from the late lias to tithonian–valanginian, broadening of the platform from the hauterivian to the aptian and then again basinal broadening from the albian onwards. 2.1.3. dubravčani grandić & vuksanović (1973) and šparica (1981) investigated the upper cretaceous to palae188 geologia croatica 55/2 189dragičević & velić: the northeastern margin of the adriatic carbonate platform ocene platform carbonate succession in dubravčani (w of karlovac – fig. 1, location 3; fig. 4). a karstified palaeorelief of middle to upper cenomanian rudist bioclastic floatstones to rudstones with bauxite occurrences is covered by the “senonian” rudist limestones. the microfossil association quoted therein indicates an upper santonian–campanian age. the cretaceous–palaeocene continuity of deposition was highlighted by fig. 2 the žumberak–samobor mts. column and lithological legend for all figures: 1) platform limestone; 2) slope to basin limestone; 3) late-diagenetic dolomite; 4) stromatolite and early-diagenetic dolomite; 5) calcareous breccia; 6) slope breccia; 7) reef limestones; 8) debrite; 9) calcarenite; 10) marl; 11) sandy matrix; 12) clayey matrix; 13) clayey limestone; 14) limestone with chert; 15) bivalve coquina; 16) bauxite; 17) calcareous algae; 18) benthic foraminifera; 19) planktonic foraminifera; 20) corals; 21) hydrozoans and stromatoporoids; 22) bryozoans and sponges; 23) bivalves in living position; 24) resedimented bivalves; 25) pelagic bivalves (“filaments”); 26) echinoderms; 27) ooids; 28) chert nodules; 29) fenestrae; 30) emersions. fig. 3 the ozalj column. to a 188 geologia croatica 55/2 189dragičević & velić: the northeastern margin of the adriatic carbonate platform šparica (1981), while grandić & vuksanović (1973) and bukovac et al. (1984) elaborated on the unconformable/transgressive relationship of the palaeocene limestones. the latter interpretation is more likely, because the thickness of upper santonian–campanian platform limestones is enormously reduced to less than 40 m. 2.1.4. martinšćak – barilović several local columns were measured through the jurassic marginal platform sequences w and sw of karlovac, in the area between dugaresa and skradska gora. the central part of the area is best studied at martinšćak hill and in barilović (fig. 1, location 4; fig. 5). the subtidal and peritidal middle lias limestones are covered by oolitic to fine-grained bioclastic grainstones formed in the tidal-bar environments of the platform margin. these sediments contain interbeds of the tempestite bioclastic grainstones to rudstones mostly composed of lithiotid bivalve shells and fragmented orbitopsella praecursor (gümbel). they are overlain by bioturbated mudstones which mark the end of the lower jurassic part of the platform carbonate sequence: this area was emergent until the late oxfordian. laterally, at the platform slope mud-supported limestones with clasts from the platform shallows and a pelagic fauna were deposited. oolitic limestones of the platform margin prograded over the slope facies. these lower jurassic carbonates are overlain by the upper oxfordian–kimmeridgian limestone which is characterised by a brecciated lower part that is gradually replaced by the oolitic–oncolitic wackestone–packstone. the next 20 m thick interval composed of wellbedded, mostly oolitic grainstones and packstones, was gradually covered by fossiliferous mudstones containing chert nodules and a mixture of the platform lithoand bioclasts with pelagic fauna. this facies indicates the kimmeridgian restoration of platform slope environments. on the platform margin the coral–hydrozoan reef had been formed, which gradually became the barrier-reef and prograded over the slope-forming fossiliferous mudstones with nodules and interbeds of chert. clasts which originated from the barrier-reef are very frequent within slope mudstones. 2.1.5. budački gornji the budački gornji section (fig. 1, location 5; fig. 6) was analysed by šparica (1981). tithonian–berriasian limestones are mostly fossiliferous mudstones with calpionellids, among which calpionella alpina lorenz was determined. they are overlain by the upper santonian to maastrichtian carbonate–clastic sediments. the transgressive contact is marked by the karstified malmian limestones covered by limestone breccias with marly matrix. these breccias are in turn overlain firstly by clayey limestone with interbeds of tuffaceous material and marl, and then by “scaglia” fig. 4 the dubravčani column (after šparica, 1981, partly modified). legend: 1) mudstones/wackestones; 2) packstones/grainstones; 3) coral limestones; 4) rudist limestones; 5) conglomerates; 6) karstified surfaces with bauxite occurrences. 190 geologia croatica 55/2 191dragičević & velić: the northeastern margin of the adriatic carbonate platform type limestone containing calcisphaeras and globotruncanids. 2.1.6. cetingrad according to sokač (1964), šparica (1981) and mrinjek (1988a, b) in the wider area of cetingrad there are two horizons of cretaceous carbonate–clastic sediments (flysch): the older one of late cenomanian–turonian (possibly early coniacian) age, which is supposed to be transgressive, and a younger one of late santonian/early campanian to palaeocene age (fig. 1, location 6; fig. 7). in the base of the cenomanian–turonian flysch there are platform carbonates of different ages: middle to upper triassic dolomites, and upper jurassic and lower cretaceous fossiliferous limestones. marls predominate in the flysch, shales are subordinate and they contain interbeds of chert, calcarenites and calcirudites. the coarse-grained units frequently contain a redeposited platform benthos, of mostly upper jurassic, lower cretaceous and cenomanian foraminifera. especially frequent are redeposited cenomanian orbitolinids (the “orbitolinid cretaceous”). younger flysch deposits of senonian–palaeocene age unconformably overlie different units – the middle–upper triassic dolomites, upper jurassic and lower cretaceous limestones and dolomites and cenomanian–turonian flysch. in the broader area they also cover the norian–rhaetian “hauptdolomit” and platform carbonates of the middle and upper jurassic, lower cretaceous and cenomanian (korolija et al., 1980). a coarse conglomeratic breccia with fragments and smaller blocks of cretaceous and jurassic limestones represents the base of the cenomanian–turonian flysch (after sokač, 1964). the breccia is followed by the typical flysch alternation of calcarenites, rarely calcirudites and marls in bouma turbidite sequences. all intervals are present, including the pelagic ones represented by the globotruncanid, platy “scaglia” limestones that also locally form thicker lenses within the flysch (fig. 7 – bk2 4-6). in the slunj area (tatar varoš) mrinjek (1988a) described cenomanian fine-grained turbidites deposited on the upper part of the slope. on the geological map of the area, the author subdivided the younger succession of upper cretaceous flysch deposits into the upper campanian and maastrichtian stratigraphic units. 2.1.7. otoka (bosanska krupa) the stratigraphic sequence of the basinal upper cretaceous sediments described by jelaska (1987) is fig. 5 the martinšćak–barilović column. 190 geologia croatica 55/2 191dragičević & velić: the northeastern margin of the adriatic carbonate platform shown in fig. 8. due to the faulted terrain, the crosssection is constructed on the basis of a survey of several smaller columns and cross-sections between otoka and bosanska krupa (fig. 1, location 7). the total thickness of explored sediments exceeds 1100 m. karstified kimmeridgian–tithonian platform carbonates are overlain by cenomanian clastic–carbonate pelagic deposits composed of thin-bedded and platy marls, clayey limestones, limestones (mudstones and wackestones) and cherts (in the form of laminae and nodules). it is supposed that pelagic sedimentation through the entire upper cretaceous was continuous, only occasionally interrupted by deposition of detrital carbonates, which appear as variously thick intercalations of bioclastic limestones – calcarenites and calcirudites containing clasts of different age, (e.g. of the upper jurassic, lower cretaceous and most frequently of the upper cretaceous carbonates), with remains of calcareous algae, foraminifera and macrofossils, especially rudists, derived from the area of the platform margin. pelagic sequences are rich in an autochthonous microfauna, globotruncanids in particular, that define the stratigraphy of these sediments through the cenomanian–maastrichtian. a sequence of graded bioclastic limestones – carbonate turbidites, occurs approximately in the middle of this part of the column and thus separates the sequence of pelagic sediments into two. the younger unit is more markedly pelagic and corresponds to the “scaglia”-type sediments. 2.1.8. subotica (bronzani majdan) lower jurassic carbonates of the platform margin and slope along the subotica creek near the village of bronzani majdan (w of banjaluka – fig. 1, location 8; fig. 9) were described by jelaska (1987). the investigated succession is approximately 200 m thick. continuity of sedimentation is recorded from the upper triassic “hauptdolomit” into the lower lias platfig. 6 the budački gornji column (after šparica, 1981). legend: 1) calpionella limestones; 2) thin-bedded limestones with globotruncanids (“scaglia” type); 3) clayey limestone; 4) marl; 5) tuff; 6) breccia. 192 geologia croatica 55/2 193dragičević & velić: the northeastern margin of the adriatic carbonate platform form mud-supported limestones containing the index alga palaeodasycladus mediterraneus (pia). these limestones are overlain by the middle lias grain-supported limestones, predominantly oolitic packstones and grainstones (with sporadic occurrences of mudstones) and the index lituolid foraminifera orbitopsella praecursor (gümbel) and lituosepta recoarensis cati (according to jurić, 1977). this sequence is unconformably overlain by slope breccias with slump structures recording the movement of unconsolidated sediment, brecciation, chaotic orientation of angular lithoclasts in the muddy matrix etc. such intervals are up to 10 m thick and contain up to 3 m thick packages of massive mudstones. the only autochthonous fossils that were discovered are the liassic involutinas, including the index species involutina liassica (jones) and “vidalinas”. the sequence of these lower jurassic deposits is overlain by the remains of upper jurassic coral–hydrozoan barrier reefs. this relationship suggests a significant hiatus – land conditions most probably existed in this area through the middle and early late jurassic. 2.1.9. jagare (banjaluka) this column was investigated in the village of jagare on the southern outskirts of banjaluka. around 80 m of sediments are exposed here, on the contact between the upper triassic carbonates and carbonate clastics of late santonian to maastrichtian age (fig. 1, location 9; fig 10). the basal part of the upper cretaceous clastic–carbonate sequence is represented by breccias and calcarenites 6 m thick containing clasts of older carbonates, that unconformably overlie the upper triassic dolomites. within the sandy and carbonate matrix there are orbitoids and siderolitids with fractured tests. the following 67 m are composed of an alternation of calcirudites, calcarenites and marls. clasts are variable – lower cretaceous orbitolinid limestones, upper cretaceous rudist and calcisphaera limestones, fragments fig. 7 the cetingrad column. 192 geologia croatica 55/2 193dragičević & velić: the northeastern margin of the adriatic carbonate platform of orbitoids and siderolitids, also sporadic grains of chert or igneous rocks. marls are the most subordinate component. in the calcarenite beds the foraminifera pseudonummoloculina heimi (bonet) and omphalocyclus macroporus (lamarck) were determined, but in the marls only unidentifiable globotruncanids and other pelagic organisms were observed. with the exception of the chaotic package of basal breccia, the lithological composition and sedimentary textures indicate a turbiditic mechanism of deposition. triassic dolomites were deposited mostly in intertidal environments, while cretaceous clastics were deposited on the slope of the carbonate platform and in the corresponding part of the basin. the source area was represented by faulted carbonate land, rudist bioherms and shallows of the platform margin. some fragments of chert and igneous rocks originated from the ladinian volcanic–sedimentary complex. 2.1.10. kotor varoš the sequence of clastic–carbonate sediments deposited in the slope-to-basin environments was investigated to define the autochthonous basinal “scaglia”-type limestones. around 50 m of sediments were studied in a profile cropping out se of banjaluka (fig. 1, location 10; fig. 11). the basal part of the column is characterised by a relatively regular alternation of calcarenites, marls and clayey “scaglia” limestones. both the clasts in the calcarenites and the finer grains of the marls originated from crushed mollusc shells (mostly of rudists) and echinoderms. fragments of aptian, albian and cenomanian limestones have also been determined, predominantly of the orbitolinid wackestone type. the matrix is carbonate mud with globotruncanids, hedbergellas and heterohelicids. pelagic foraminifera have also been found in the marls, but they are particularly frequent in the “scaglia” limestones with a rich association of globotruncanids. calcirudites and calcarenites prevail in the third quarter of the column and “scaglia” limestones in the uppermost part. the stratigraphic range of these sediments was determined on the basis of globotruncanids, since the association contains nearly 20 species, which mostly have a broad upper cretaceous span. some of the species found – globotruncanita calcarata (cushman) and fig. 8 the otoka (bosanska krupa) column (after jelaska, 1987). 194 geologia croatica 55/2 195dragičević & velić: the northeastern margin of the adriatic carbonate platform fig. 9 the subotica (bronzani majdan) column (after jelaska, 1987). fig. 10 the jagare (banjaluka) column. 20 10 o unit facies environments "r'\~ "ri---------+----. j -rr-.--------1 maim ~ hydrozoan reef protected ~ ~ ~ rplatform '" .. 30 15 o o .~ f­ :::j m ~ 3·1:;~~ tl (3'tl "v" [7 b l1 d b.y 1. * ~ .. o) ... o. 0. o 0 f -slope breccias grain-supported limestones (ooids, pellets, biodasts) micrites with pa/aeodasycjadus dolomitas, dol. micrites, algal boundstones age lithology environments slope to basin ~;i~~~ gl c. o '" -q£-.goos:/. odoo.o.,,:o".';} 8..2 c. -+===3~?:z?[ ~~ca~rb~o~n~ate~~ c. !l! l shelf/platform ::> j!: intertidal/supratidal fossils .0 " '" globotruncanids ompha/ocyc/us macroporus siderolites sp. calcisphsers aptian-albian orbitolinids .. .. c. " '" .. "c gl i~ 194 geologia croatica 55/2 195dragičević & velić: the northeastern margin of the adriatic carbonate platform g. stuartiformis (dalbiez) are index fossils for the upper campanian and maastrichtian. 2.1.11. kotor varoš – skender vakuf in order to study the slope and basinal facies, a geological cross-section was measured in the upper cretaceous carbonate clastics and limestones which are approximately 700 m thick, along the kotor varoš–skender vakuf road, (fig. 1, location 11; fig. 12). the first 350 m of the column is characterised by regularly stacked sequences of thicker calcirudite/calcarenite beds with terminal members composed of thinner marl beds, sporadically by clayey “scaglia” limestones. in the next 150 m of the middle part of the column there are mostly marls with occasional interbeds of calcirudites and calcarenites, while the uppermost 200 m is composed almost entirely of thin-bedded marly “scaglia” limestones containing only two thicker calcirudite interbeds. the basal part of the column can be interpreted as turbidites of the lower slope or proximal part of the basin. the upper half with marls and predominating “scaglia” limestones consists of autochthonous basinal sediments. the sporadic thick calcirudite beds represent debrites. 2.1.12. paunovići (skender vakuf) this column was measured in paunovići village se of banjaluka (fig. 1, location 12). the horizons near the contact between the lower aptian limestones and the maastrichtian to palaeocene carbonate clastics were studied. the thickness of the explored sediments is 26 m (fig. 13). lower aptian platform carbonates are represented by well-bedded fossiliferous mudstones and wackestones and rudist coquinas. a microfossil assemblage with numerous foraminifera of extensive early cretaceous range contains early aptian sabaudia briacensis arnaud-vanneau, fragments of palorbitolinids and bacinellas. karstified aptian limestones are overlain by a 30 cm thick sequence of basal conglomerate, with pebbles of limestones, carbonate sand and mud matrix. they are followed by intraclastic–fossiliferous wackestones and then predominantly biocalcarenite that mostly contains clasts of abraded rudists, bryozoans and corallinaceans. probable source rocks were rudfig. 11 the kotor varoš column. 196 geologia croatica 55/2 197dragičević & velić: the northeastern margin of the adriatic carbonate platform ist assemblages near the platform margin. the central part of the carbonate clastic sequence is composed of an alternation of biocalcirudites and biocalcarenites containing orbitoids, siderolitids and omphalocycles of campanian and maastrichtian age. biocalcarenites containing ethelia alba (pfender) in the topmost part of column determine the palaeocene age. depositional environments of the maastrichtian sediments are defined as the back-reef shallows–forereef–upper part of the platform slope. 2.1.13. vidovo vrelo near the vidovo vrelo spring there is a road-cut in maastrichtian–palaeocene clastics 8 m wide and 2.5 m high (fig. 1, location 13; fig. 14). the exposed rocks are heterogeneous and of complex composition. within the sandy–clayey matrix there are irregularly spaced fragments and thinner bedded fragments and blocks of various types of platform shallow marine limestones ranging in age from barremian to maastrichtian. the clasts are usually subrounded and measure from 5 to 80 cm. there are also disintegrated and folded beds, parts of beds or lithoclasts of clayey mudstones and marls of campanian–maastrichtian age that together form subaqeous slump structures. palaeontological analyses of clasts revealed their age as either albian or turonian–early campanian on the basis of numerous foraminifera species such as mesorbitolina texana (roemer), m. subconcava leymerie, m. pervia douglas, pseudonummoloculina heimi (bonet), moncharmontia apenninica (de castro), m. compressa (de castro), dicyclina schlumbergeri munier-chalmas, scandonea samnitica de castro, murgella lata lupertosinni, keramosphaerina tergestina stache etc. a rich association of the campanian and maastrichtian calcareous nanoplankton was found both in clasts and in the slumped marl beds. the youngest clasts are either redeposited bioclasts or complete specimens of maastrichtian rudists. notably, there are no clasts of cenomanian age, suggesting that the stratigraphic base of the maastrichtian transgressive clastic deposits on the platform margin and slope were early albian and turonian to early campanian limestones. the described clastic deposits of the vidovo vrelo outcrop can be defined as slump structures incorpofig. 12 the kotor varoš–skender vakuf profile. p 196 geologia croatica 55/2 197dragičević & velić: the northeastern margin of the adriatic carbonate platform rated in the debris flow breccia. due to the fact that no autochthonous fossils were found in the sandy–clayey matrix of these sediments, the age is estimated according to the age of the clasts, which are youngest maastrichtian and oldest palaeocene. 2.1.14. trijebovo (mrkonjić grad) near the village of trijebovo, w of jajce (fig. 1, location 14) a geological column of approximately 40 m was analysed at the contact between upper albian limestones and carbonate clastics of maastrichtian–palaeocene age. the lithological composition of maastrichtian clastics is very interesting because this unit is mostly represented by conglomerate–breccia (fig. 15). these karstified upper albian platform limestones have identical facies characteristics to those in the liskovica and bešpelj areas (see section 2.1.15.), and are transgressively and unconformably overlain by the maastrichtian coarse carbonate clastics, mostly calcirudites (breccia) with subordinate calcarenites. basal biocalcarenites consist mostly of rudist fragments and benthic foraminifera of the platform margin and slope provenance (genera orbitoides, siderolites, omphalocyclus), with sporadic albian to upper cretaceous limestone lithoclasts containing pithonellid calcisphaeres. the predominating breccia member consists of lithoclasts of the same composition and age as the calcarenites, only of larger dimensions. these are most frequently subrounded to angular clasts of upper cretaceous rudist and calcisphaere limestones, together with less frequent clasts of the albian orbitolinid and ostracod limestones. there are also rudist and bryozoan bioclasts. the matrix of carbonate sand has the same petrographic composition as the lithoclasts. the only internal structure in the breccia is a general gradation (fining-upwards). the stratigraphic range of these clastics is estimated from the age of the fragments – as the youngest bioclasts contain maastrichtian foraminifera it can be interpreted as being of late maastrichtian to palaeocene age. fig. 13 the paunovići (skender vakuf) column. 198 geologia croatica 55/2 199dragičević & velić: the northeastern margin of the adriatic carbonate platform 2.1.15. liskovica – bešpelj several detailed columns were measured n of jajce, along the contact of the younger lower cretaceous platform carbonates with the clastic–carbonate sediments of the younger upper cretaceous deposited in slope to basin environments. the locations include brenica (in the canyon of the vrbas river), liskovica, donji bešpelj, kober, crvene stijene, poljane and brnjići. in the base of the upper cretaceous clastic sediments there are karstified albian limestones, the palaeo-depressions (dolinas) of which are filled with large and economically very important bauxite deposits. the best known are those at the liskovica and bešpelj localities (fig. 1, location 15) which have similar stratigraphic–sedimentological characteristics and will be illustrated with a single stratigraphic column (fig. 16). the basal platform limestones are mostly represented by muddy varieties with a marked shallowing-upward tendency (stacking of mudstone–fenestral mudstone small-scale cycles), occasionally with emersions that resulted in interbeds of emersion mud-pebble conglomerates. there are also sparse interbeds of rudist coquinas. an upper albian age was determined on the basis of the microfossil assemblage containing orbitolinids neoiraquia insolita (decrouez & moullade) and valdanchella dercourti decrouez & moullade. the karstified palaeorelief of the albian limestones with sporadic bauxite deposits in palaeodolinas and depressions was transgressively overlain by either the upper santonian and campanian platform margin carbonates or by the upper santonian to maastrichtian flysch deposits. contacts are marked by a very low angular unconformity. when traced along the strike at liskovica, the base of the sequence is variable – e.g. there are either conglomerates with pebbles of basal limestones, or shallow-marine grain-supported limestones, or even rudist biolithites. biolithites are most frequently found at bešpelj, where they directly overlie bauxite deposits. rudists are in the growth position, intraformational space being filled up with carbonate sand consisting of rudist fragments, benthic foraminifera and fragments of echinoids, bryozoans, etc. the biolithites are covered by rudist coquinas passing both vertically and laterally into alternations of biocalcirudites and biocalcarenites. the continuation of the column is marked with an increasing proportion of marl in alternation with calcarenites and calcirudites, and deposits gradually acquire a turbiditic character. carbonate clasts originated exclusively from the destruction of rudist lithosomes and their redeposition in the reef and fore-reef shallows and on the platform slope. the facies characteristics of these deposits clearly reflect changes of depositional environments in the following sequence: carbonate shallows–reef–forereef–platform slope. a depositional age of upper santonian to maastrichtian is documented by numerous index fossils – benthic foraminifera such as murgella lata luperto-sinni, keramosphaerina tergestina stache, pseudorhapydionina mediterranea (de castro), orbitoides media (d’archiac), siderolites calcitrapoides lamarck, omphalocyclus macroporus (lamarck), and numerous pelagic microorganisms – foraminifera (most frequently globotruncanids), pithonellid calcisphaeras and calcareous nannoplankton. 2.1.16. seoci (jajce) in the seoci village on the jajce–bešpelj road there is a 20 m long and 4–6 m high road-cut opened in debrites (fig. 1, location 16; fig. 17). fig. 14 the vidovo vrelo outcrop. legend: 1) sandy–clayey matrix; 2) resedimented maastrichtian rudists; 3) santonian–campanian clayey mudstone; 4) barremian to santonian limestones. 198 geologia croatica 55/2 199dragičević & velić: the northeastern margin of the adriatic carbonate platform these coarse-grained sediments consist of variously sized lithoclasts in a sandy–clayey matrix: larger clasts measure 5–200 cm, and smaller ones, which are the most frequent, less than 5 cm. clasts originated from various types of limestones of barremian to albian age, and also from sequences of upper cretaceous clastic–carbonate sediments. they are mostly angular or weakly rounded. marl clasts are, in addition, deformed. the sediment is completely unsorted and chaotic. since the terrain is covered it is impossible to study lateral and vertical relationships. nevertheless, this is interpreted as a channel sedimentary body because the largest clasts were mostly found in the central part of the outcrop and their size gradually diminishes towards both flanks. it is also concluded that such sediments were probably formed from massive rock-falls which occurred at the platform margin as a consequence of synsedimentary seismo-tectonic activity. the accumulated material was transported down the platform slope in the form of grain flows which incorporated increasing amounts of muddy material and were thus changed into debris flows. fig. 15 the trijebovo (mrkonjić grad) column. 200 geologia croatica 55/2 201dragičević & velić: the northeastern margin of the adriatic carbonate platform according to the stratigraphic age of the clasts and matrix these debrite deposits are of maastrichtian age. 2.1.17. ravanac this column was measured ne of jajce (fig. 1, location 17), and the sequence of deposits is approximately 45 m thick, composed of cenomanian and santonian limestones and maastrichtian–palaeocene carbonate clastics (fig. 18). the cenomanian part of the column (15 m thick) starts with a coquina of small current-oriented rudists. it is covered by the alternation of mostly fossiliferous varieties of platform carbonates – mudstones, pelletal mudstones, wackestones and packstone–grainstones within which a stromatolite interbed >1 m thick was observed. these limestones are of middle cenomanian age, since they contain a benthic foraminifera association where the most important species are conicorfig. 16 the liskovica–bešpelj column. neoiraquia insolita 200 geologia croatica 55/2 201dragičević & velić: the northeastern margin of the adriatic carbonate platform bitolina conica (d’archiac), sellialveolina viallii colalongo, chrysalidina gradata d’orbigny and pseudolituonella reicheli marie. karstified cenomanian limestones are overlain by a 70–150 cm thick “layer” of bauxite, which is in turn, gently unconformably, covered by a 17 m thick package of santonian rudist platform limestones consisting of an alternation of fossiliferous fenestral mudstones and wackestones. their upper santonian age is confirmed by the presence of murgella lata luperto-sinni. fig. 18 the ravanac column. fig. 17 the seoci (jajce) outcrop. iage lithology environments fossils = ! slope to basin i calcareous nannoplankton • "sk1eroiites , 5 slope to basin ctjlcitrtjpoides :> 0tbit0k:i8a media • murgella fate 1 e • u subtidal , m.cliterranea • m j • • u) 10 ~ chrysslidina •• gradata • • seilia/veolina vshi; e shallow !~ subtldalotbitoiins (c.) intertidal ~ conics ~ ~ rudists o 202 geologia croatica 55/2 203dragičević & velić: the northeastern margin of the adriatic carbonate platform santonian limestones are transgressively and unconformably overlain by maastrichtian–palaeocene carbonate clastics. they are represented by the alternation of biocalcirudites, biocalcarenites, marls and clayey micrites. the first three members are typical for the turbidite sequences of the platform slope environment, while the inserts of clayey limestones pertain to the basinal environment with autochthonous pelagic sedimentation. in the coarse-grained intervals, lithoclasts are of albian to campanian age, including slope benthic foraminifera of campanian and maastrichtian age (orbitoids, siderolitids). pelagic organisms – calcareous nannoplankton and globigerinids define the palaeocene age of the clayey limestones. 2.1.18. bila the bila column is approximately 100 m thick (fig. 19) and was measured in order to investigate sediments of completely basinal characteristics. it is located in the canyon of the small river bila, nw of zenica (fig. 1, location 18). the lowest 30 m consist of an alternation of globotruncanid mudstones, cherts, silicified mudstones, mudstones with chert lenses, clayey mudstones and marls. mudstones are autochthonous pelagic sediment and include frequent globotruncanids, calcisphaerulids and heterohelicids. marls with parallel lamination in the lower parts of beds, represent distal turbidites, while numerous fragmented planktonic forms in the topmost parts of beds indicate hemipelagic sedimentation. the brown-reddish to greenish-grey cherts represent radiolarites. the middle part of the column, (40 m thick), consists of an alternation of calcirudites, calcarenites, marls and clayey micrites. the coarse-grained members are composed of rudists, bryozoans, lithothamnion and benthic foraminiferal bioclasts, as well as clasts of the upper cretaceous limestones, clasts of orbitolinid limestones and other types of younger lower cretaceous limestones. all these clasts originated from carbonate units of the platform margin and upper slope. marls prevail in the third, terminal part of the column, within a 30 m thick sequence. the lower part of this interval consists of complete turbidite sequences deposited in the middle of a depositional fan. undercut fig. 19 the bila column. 202 geologia croatica 55/2 203dragičević & velić: the northeastern margin of the adriatic carbonate platform sequences (mostly tb–e) in the upper part indicate distal turbidites. the described deposits are composed of material originating from the destruction of rudist lithosomes and of shallow marine carbonates of the platform margin and platform slope, as well as from the autochthonous basinal pelagic deposits. a campanian–maastrichtian age is determined on the basis of the globotruncanid association. 2.1.19. guča gora this column was surveyed on the se slopes of vlašić mt., w of zenica (fig. 1, location 19). a sequence of sediments 25 m thick comprises cenomanian carbonates in contact with the youngest upper cretaceous carbonate clastics (fig. 20). cenomanian limestones are represented by the irregular alternation of mudstones, fossiliferous wackestones to grainstones, intraclastic grainstones and rudist coquinas deposited in the platform shallows, mostly under the influence of stronger currents. several index species of cenomanian orbitolinids were identified from the fossiliferous grainstones. karstified cenomanian grainstones are covered by an approximately 10 cm thick interbed of bauxite. above the bauxite there is a thinner bed of bauxitic clay, covered by a thinner bed of calcarenite, and then by approximately 150 cm of marl. the marl is overlain by a thicker biocalcirudite bed followed by the relatively regular alternation of well-bedded biocalcarenites and marls. the depositional environment was the carbonate platform slope. clasts in calcirudites and calcarenites include lower aptian limestones with orbitolinids, upper albian algal limestones, cenomanian limestones, calcisphaera limestones, rudist bioclasts and fragmented campanian–maastrichtian foraminifera (siderolitids, orbitoids and globotruncanids). in the marls there are numerous tiny unidentifiable globotruncanids that belong to the autochthonous pelagic sediment, as well as calcareous nannoplankton in the topmost parts of the marl beds. according to the fossil content, the described deposits are of campanian and maastrichtian age. 2.1.20. kaonik the column was measured sw of zenica (fig. 1, location 20), and the geology of this locality is comparable to that at the jagare (banjaluka) area. upper triassic late-diagenetic dolomites in the base are unconformably overlain by late cretaceous carbonate clastics (fig. 21) composed of the regular alternation of calcirudites, calcarenites, marls and clayey mudstones. two bodies of breccio–conglomerates are especially marked in the upper part of the column. calcirudites and calcarenites are composed of rudists and large foraminiferal bioclasts of campanian and maastrichtian age (orbitoids and siderolitids), as well as fig. 20 the guča gora column. 204 geologia croatica 55/2 205dragičević & velić: the northeastern margin of the adriatic carbonate platform lithoclasts of cenomanian and turonian calcisphaera limestones and aptian and albian limestones. the mud matrix contains frequent fragmented globotruncanids. the marls and clayey limestones contain undeterminable pelagic foraminifera. the structure and composition of the breccias is very interesting. they comprise limestone clasts and pebbles from a few to 40 cm in size. the sparse matrix consists of clayey carbonate sand. clasts originate from the platform limestones of various stratigraphic ages, determined mostly on the basis of microfossils. according to their sedimentological characteristics, the described deposits represent typical turbidites which most frequently contain complete bouma sequences. both chaotic sequences of breccia within the turbidites have erosive lower surfaces, and are interpreted as debris flows. the depositional environment of these clastics was the toe-of-the-slope and transition to the basin. the source area was the faulted and locally emerged platform margin, where material was provided by the rudist biolithites and erosion of older rocks. 2.1.21. čardak livade this location is n of glamoč (fig. 1, location 21) where, during the late cretaceous, there was an intraplatform trough (one of several) that existed in the broader area of the ne margin of the adriatic carbonate platform. a sequence of sediments was studied from the middle cenomanian limestones in the base through the carbonate clastics and limestones of coniacian– campanian age to the maastrichtian carbonate clastics (fig. 22). basal middle cenomanian limestones are represented by the alternation of fossiliferous varieties – from wackestone to grainstone, formed in subtidal environments. this is confirmed by very rich associations of benthic foraminifera including chrysalidina gradata d’orbigny, broeckina (pastrikella) balcanica cherchi et al., pseudorhapydionina dubia de castro and p. laurinensis de castro. the karstified palaeorelief of these limestones is covered by a 1–3 m thick bauxite body which is transgressively (with low angle unconformity) overlain by three thick calcirudite beds fig. 21 the kaonik column. 204 geologia croatica 55/2 205dragičević & velić: the northeastern margin of the adriatic carbonate platform of carbonate breccia, composed of fragments of basal cenomanian limestones that measure 5–40 cm. they are calcite-cemented. the breccia is covered by fenestral mudstones followed by thick-bedded wackestones. these rocks contain a microfossil foraminiferal association pseudorhapydionina mediterranea (de castro), accordiella conica farinacci, dicyclina schlumbergeri munier-chalmas and pseudocyclammina sphaeroidea gendrot of coniacian to santonian age, and were deposited in the platform shallows. contact with transgressive maastrichtian–palaeocene carbonate clastics shows no angular unconformity and lacks signs of karstification. this sequence starts with biocalcirudites followed by the alternation of biocalcarenites and marls. campanian–maastrichtian benthic foraminifera (orbitoids, siderolitids and omphalocycles) were found in the calcarenites, and some associations of calcareous nannoplankton determined in marls indicate the maastrichtian–danian contact horizon. detritus originated from destroyed rudist bioherms and from carbonate sand and mud of the platform shallows. the poorly developed gradation and parallel lamination depict local transport in fore-reef environments. 2.1.22. strojice the column was measured nw of kupres (fig. 1, location 22), where an exposed sequence (85 m thick) consists of carbonates of platform margin and carbonate clastic slope deposits occurs towards one of the intraplatform troughs in the general area of the ne margin of the adcp (fig. 23). the platform margin carbonates are represented by a 12 m thick alternation of fore-reef bioclastic grainstones and fossiliferous wackestones, and contain rare mudstones of more restricted environments. there are relics of biolithite bodies in the grainstones that contain corals, stromatoporoids, bryozoans, echinoids, algae, foraminifera, gastropods and bivalves (including rudists). the rudists are mostly redeposited, but there are also some in growth position, representing the reef environment at the margin of one of the intra-platform troughs. the upper barremian age was determined by discovery of the orbitolinids rectodictyoconus giganteus schroeder and palorbitolina lenticularis (blumenbach). the karstified barremian limestones are transgressively and unconformably overlain by a 12 m thick fig. 22 the čardak livade column. subtidal 206 geologia croatica 55/2 207dragičević & velić: the northeastern margin of the adriatic carbonate platform sequence of calcareous basal breccia–conglomerate with pebbles and fragments of barremian to cenomanian limestones. fine-grained carbonate mud matrix contains unidentifiable planktonic foraminifera. lithoclasts are orbitolinid limestones of lower aptian, albian and cenomanian age, while bioclasts are composed of albian and cenomanian orbitolinids, gastropods, and a lot of bivalves, mostly rudists. the breccia–conglomerate is covered by a 55 m thick transgressive sequence of massive fine-grained clayey arenite, which only sporadically exhibits weak bedding. the particles are limestone–dolomite sand-sized grains, rarely chert and igneous rocks grains, with clayey mudstone matrix with tiny globigerinids. gradation and parallel lamination are rarely observed in this interval. these rocks were deposited in shallow marine environments with a low coastline and flattened lowlands behind it. the arenites are overlain by 3 m of marl and a final, 5 m thick massive bed composed of unsorted biocalcirudite with up to 5 cm sized particles of lower cretaceous limestone lithoclasts and rudists, orbitoids, siderolitids and heterohelicids. the matrix is fine-grained carbonate sand. the described biocalcirudite is followed by flysch deposits with the characteristic alternation of calcarenites and marls. this depositional environment is interpreted as a carbonate slope where the source material was derived from both older carbonate rocks of the platform margin and campanian–maastrichtian rudist bioherms and carbonates from the platform shallows. 2.1.23. kupres at the southern margin of the kupres polje, 75 m of upper tithonian and berriasian carbonates in contact with the upper cretaceous carbonate clastics were studied. these were deposited in fore-reef to platform slope environments (fig. 1, location 23; fig. 24). due to the complex recent tectonic relationships in the area, it is difficult to define whether this is the ne margin, the “main” slope of the adcp, or just the margin and slope of one of the intraplatform troughs in the broader area of the platform margin. fig. 23 the strojice (janj) column. u . b ar re m ia n 206 geologia croatica 55/2 207dragičević & velić: the northeastern margin of the adriatic carbonate platform interestingly, the basal tithonian–berriasian sediments and transgressive upper cretaceous carbonate clastics in part of this column both represent slope facies characterised by the processes of destruction and redeposition of the tithonian–berriasian reef-forming organisms and of lithoclasts derived from platform margin deposits of units older than upper cretaceous. the basal, thick-layered limestones are mostly composed of clasts of reef-building organisms – corals, hydrozoans, stromatoporoids, bryozoans, sponges, echinoids, gastropods, bivalves and algae. in the grain-supported varieties they are the only component of the rock, while in the mud-supported carbonates they represent isolated clasts in a matrix containing autochthonous pelagic microorganisms – calpionellids, radiolarians and small foraminifera. these limestones are transgressively overlain by thick-bedded breccias composed of both rounded and angular clasts which originate from the platform and slope carbonates of a wide stratigraphic time span, ranging from middle jurassic limestones with filaments, upper jurassic forereef and reef limestones, tithonian–berriasian fossiliferous calpionella mudstones, valanginian–hauterivian fossiliferous packstone–grainstones, barremian–aptian orbitolinid limestones, and bioclasts of hydrozoans, corals, molluscs, rudists etc. the matrix is represented by carbonate mud that contains tiny upper cretaceous planktonic foraminifera. gradation is observed in some of the breccia beds. the base of each layer is frequently irregular, due to erosion of the underlying layer. lateral relationships in the field cannot be explored because of the quaternary cover, and it can only be assumed that these breccias are debrites deposited on the platform slope. the large stratigraphic range and variety of clasts suggest fast and intense mechanical weathering of the faulted and partly also emerged steep platform margins. large masses of coarse-grained material were accumulated along a broad front and transported down the slope by gravitational currents. 2.2. correlation of studied geological columns on the basis of analysis of the relationships of the investigated facies along the ne margin of the adriatic carbonate platform only partial correlations are possible, although rarely within jurassic and lower cretaceous deposits and more frequently within upper cretaceous sequences. the jurassic palaeogeography of the investigated area was characterised by the predominant deposition of oolithic limestones during the early and middle jurassic, but also a long-lasting hiatus along the very platform margin, lasting from the middle lias to the kimmeridgian (figs. 25–27). in the kimmeridgian and the tithonian the area was characterised by barrier coral–hydrozoan reefs (fig. 28). such relationships fig. 24 the kupres column. 208 geologia croatica 55/2 209dragičević & velić: the northeastern margin of the adriatic carbonate platform have been noticed on the martinšćak–barilović (fig. 5) and subotica (fig. 9) geological columns, which can be well correlated. on the platform slope, predominantly mud-supported limestones comprising pelagic organisms and lithoand bioclasts originating from shallow-marine marginal platform environments were deposited contemporaneously from the middle lias. in some levels clasts are so frequent that they form breccia deposits, which in places represent part of the debris flows, e.g. in the žumberak–samobor mts. (fig. 2), subotica (fig. 9) and kupres (fig. 24) columns. data on the lower cretaceous marginal facies are very scarce. in the recent geological framework lower cretaceous deposits are common, but are mostly of inner platform facies, e.g. subtidal, lagoonal or peritidal algal–foraminiferal limestones with frequent salpingoporellas, orbitolinids and other microfossils. some temporary emersions have been documented within the lower cretaceous deposits, the most important of which were those in the albian, including a lengthy hiatus in the jajce area, which lasted until the late santonian (liskovica–bešpelj column, fig. 16), or even the maastrichtian (trijebovo column, fig. 15), and included development of significant bauxite deposits. in the area of janj (south of jajce) an important emersion was recorded from the late barremian/early aptian to the late cenomanian (strojice column, fig. 23), which also resulted in frequent clayey mudstone interbeds within the albian deposits of the neighbouring shallowmarine areas. these long-lasting emersion phases represent the consequence of tectonic activity in the marginal part of the platform. the very variable successions of the cenomanian deposits are especially interesting, indicating differential tectonic influences in the studied area. along the platform margin, cenomanian deposits have been documented in the vicinity of karlovac (dubravčani, fig. 4), in the kordun area (cetingrad, fig. 7), east of jajce (ravanac, fig. 18), in vlašić mt. (guča gora, fig. 20), north of glamoč (čardak livade, fig. 22) and in the janj area (strojice, fig. 23). among these columns, dubravčani, ravanac and čardak livade are very similar, since karstified cenomanian limestones are overlain by bauxite occurrences and deposits, followed by coniacian–campanian limestones. in the guča gora column bauxites are covered by maastrichtian flysch. upper cretaceous slope and basin deposits are determined in most of the columns, with the most common stratigraphic range being from the campanian to the maastrichtian. in the cetingrad column (fig. 7) older deposits (cenomanian to campanian) are also present, while in the otoka column (fig. 8) sedimentary continuity from the cenomanian to the maastrichtian was supposed. in the investigated marginal area of the adcp, from žumberak to kupres, stratigraphically different deposits, ranging from upper triassic to the upper santonian/lowermost campanian age, are overlain by youngest upper cretaceous clastic–carbonate deposits, indicating significant pre-santonian synsedimentary tectonics. upper triassic shallow-marine carbonates are overlain by upper cretaceous flysch deposits in cetingrad (fig. 7), jagare (fig. 10) and the kaonik columns (fig. 21). upper jurassic limestones and dolomites or tithonian–berriasian slope–basin “calpionella limestones” represent the underlying deposits of flysch in the ozalj (fig. 3), budački gornji (fig. 6), cetingrad (fig. 7), otoka (fig. 8) and kupres columns (fig. 24). lower aptian deposits are overlain by upper cretaceous flysch deposits in the paunovići column (fig. 13), and upper albian in the trijebovo column (fig. 15). an upper cretaceous age for deposits of underlying flysch has been determined in the cetingrad column (cenomanian; fig. 7), liskovica–bešpelj and ravanac (upper santonian/lower campanian; figs. 16 and 18), guča gora (lower to middle cenomanian; fig. 20), čardak livade (coniacian to lower campanian; fig. 22) and strojice (middle cenomanian to coniacian; fig. 23). according to the results obtained by investigation at the aforementioned localities it is obvious that palaeogeographic relationships were variable during the geological history of the northeastern margin of the adcp. by correlation of events recorded in different columns, geodynamic changes may be reconstructed, facilitating the evolution of the ne platform margin to be deciphered. 2.3. carbonate sequences of the northeastern margin of the adriatic carbonate platform in spite of the fact that the adriatic carbonate platform was isolated as a separate shallow marine depositional system on the adria plate during the early jurassic, description of the carbonate sediments of the platform margin will start with the upper triassic deposits. upper triassic carbonates (“hauptdolomit”) and lower jurassic platform carbonates are both in sedimentological and stratigraphic continuity, in spite of the fact that adcp started as an isolated carbonate platform system from the latest sinemurian or earlier pliensbachian. for the purpose of this review, the two characteristic groups of sediments will be described separately – the shallow marine carbonate facies of the platform margin (1) and the facies of the platform slope together with the basinal facies (2). it should be pointed out that “hauptdolomit” was the palaeoenvironmental precursor on the entire shallow marine area of the adria microplate which split into several isolated carbonate platforms. within the carbonate sequences of all those periadriatic platforms there are “hauptdolomit” deposits. 2.3.1. platform shallow marine facies along the ne margin of the adcp in the ne marginal part of the adcp, carbonate platform sediments ranging from the early jurassic to the 208 geologia croatica 55/2 209dragičević & velić: the northeastern margin of the adriatic carbonate platform end of the cretaceous were determined. numerous geological columns and sections were investigated between the žumberak area in croatia to the kupres polje and river bosna in bosnia and herzegovina (fig. 1). in addition, the available published data were used, although they are mostly older because field work in this area was impossible for almost 15 years. 2.3.1.1. upper triassic shallow marine carbonate sediments of upper triassic age are found in almost continuous strike along the entire ne margin of the adcp, from western slovenia to southern montenegro and northern albania. due to the fact that individualisation of the adcp happened in the early jurassic, upper triassic carbonates cannot be considered as adcp deposits but as their older foundation. two characteristic formations of different lithological composition are discerned – (1) the limestone–dolomite formation, partly comparable with the well known “dachstein limestones” of the southern alps, and (2) the dolomite formation with prevalence of the so-called “hauptdolomit” or the “dolomia principale” (“main dolomite”), distributed throughout the perimediterranean region, also with a holotype in the southern alps. the platform margin between the žumberak region and central bosnia has a base of “hauptdolomit”, composed of light-coloured layered stromatolitic and laminated early-diagenetic dolomites, alternating with darker medium to coarse-crystalline late-diagenetic dolomites. occasionally, there are also thin layers or lenses of grey limestones, mostly fossiliferous wackestones to grainstones. in the limestones, the following association of foraminifera of upper triassic involutinides was determined: aulotortus friedli (kristian-tolmann), a. sinuosus (weynschenk), auloconus permodiscoides (oberhauser) and triasina hantkeni majzon, with occasional occurrences of macrofossil megalodon shells. in the marginal parts of the platform in herzegovina, montenegro and in northern albania, the upper triassic is developed into two formations (as in the southern alps) – the limestone formation consisting of the megalodon (“dachstein”) limestones and the dolomite formation (“hauptdolomit”). similar conditions are also found at the platform margin in western slovenia where the lower part of the upper triassic is represented by dolomites in a facies corresponding to the “hauptdolomit” and the upper part by dachstein limestones. 2.3.1.2. lower jurassic in croatia, lower jurassic carbonates of the platform margin crop out at numerous localities in žumberak – ne and e of sošice, and in the samobor mts. (šikić & basch, 1975; pleničar et al., 1976; babić, 1976; šikić et al., 1978; bukovac & sokač, 1989; bucković et al., 2001), in the surroundings of karlovac, along the downstream parts of the mrežnica and korana river valleys (bukovac et al., 1974, 1984), and in the kordun area at several localities near slunj (sokač, 1964; korolija et al., 1980; šparica, 1981). the shallow marine middle lower jurassic platform fossiliferous mudstones with benthic microfossils were described by šparica (1981) at a single location in the banovina region (prosinja west of žirovac), where they are found “surrounded” by deep marine jurassic facies. similar sediments are found in nw bosnia – n and ne of bihać (polšak et al., 1977), in the vicinity of bosanska krupa (mojičević et al., 1978), w of banjaluka (đerković et al., 1976; mojičević et al., 1977; jelaska, 1987), in the surroundings of ključ (vrhovčić et al., 1983), in the region between the upstream part of the sana river valley and the river vrbas (near manjača), and also s of banjaluka (marinković & ahac, 1980). in central bosnia, lower jurassic limestones and dolomites are found not only at several locations in the vicinity of jajce (marinković & ahac, 1980), south-west of šipovo and in the northern part of the kupres polje (vujnović, 1980), but also along the western and southern margin of the same polje (papeš, 1972, 1985) as well as near prozor and jablanica lake in the neretva river canyon (sofilj & živanović, 1979). lower jurassic carbonates are represented by fossiliferous limestones, partly wackestones to packstones that were mostly deposited in the restricted inner platform shallows and/or lagoons, and partly packstone– grainstones from the platform shallows close to the very margin of the platform where the oolitic limestones also frequently occur (figs. 25, 26). they were found in the vicinity of karlovac in croatia (bukovac et al., 1974), and especially in western (jelaska, 1987; mojičević et al., 1979) and central bosnia (papeš, 1975, 1985; sofilj et al., 1980; vujnović, 1981; vrhovčić & mojičević, 1983). dolomites are almost entirely of late-diagenetic origin occurring as thin layers or lenses in the limestones, or occasionally as an equal part of the limestone–dolomite sequence. these sediments are relatively rich in fossils, mostly molluscs – gastropods, bivalves, brachiopods, as well as calcareous algae and benthic foraminifera. the early jurassic age of these carbonates is determined from a benthic microfossil assemblage containing the early and middle lower jurassic (hettangian to pliensbachian) index species – algae palaeodasycladus mediterraneus (pia), sestrosphera liasina pia, solenopora liasica le maitre, and foraminifera lituosepta recoarensis cati and orbitopsella praecursor (guembel). uppermost lower jurassic (toarcian) carbonates at this margin, but also on the entire platform are markedly barren with no significant or index fossils. the lower jurassic of the ne margin of the adcp in slovenia, from tolmin (buser, 1987) towards vrhnika and novo mesto (buser, 1968, 1969; buser 210 geologia croatica 55/2 211dragičević & velić: the northeastern margin of the adriatic carbonate platform fig. 25 recent position of the pliensbachian ne platform margin deposits. legend: 1) inner platform carbonate deposits; 2) ooid grainstones; 3) “lithiotis” limestones; 4) slope to basin deposits. fig. 26 recent position of the toarcian ne platform margin deposits. legend: 1) emerged area; 2) ooid grainstones; 3) “spotty limestones”; 4) slope to basin deposits. n n 210 geologia croatica 55/2 211dragičević & velić: the northeastern margin of the adriatic carbonate platform et al., 1967; dozet & šribar, 1998a), krško and gorjanci (i.e. žumberak) area (pleničar et al., 1976) consists of well layered dark-coloured platform carbonates – interlayered mudstones, fossiliferous wackestones, oolitic grainstones and late-diagenetic dolomites. this carbonate sequence frequently contain interbeds of the lithiotid bivalve (lithiotis, cohlaerites; fig. 25), gastropod and brachiopod coquinas. the lower jurassic carbonates of the ne platform margin in herzegovina and all the way through montenegro to northern albania (to the cukali–budva trough) are mostly covered by younger sediments. the sparse exposed sections are also marked by oolitic limestones (figs. 25, 26) containing intercalations of latediagenetic dolomite, only in the lower jurassic limestones which can be attributed to environments close to the marginal part of the platform found w of nikšić, ne of podgorica and in the rumija mt. (vujisić, 1972; živaljević et al., 1971; mirković et al., 1977; radoičić, 1966). 2.3.1.3. middle jurassic within the study area of the platform margin there are not many data of the middle jurassic sediments. they were mentioned at several locations, but they are only supposed as being associated with the lower jurassic carbonates and they have not so far been palaeontologically determined. in this way the middle jurassic was interpreted in žumberak and in the samobor mts., as being composed of both the micrite varieties and oolitic limestones (radoičić, 1966; pleničar et al., 1976; šikić et al., 1978). similar carbonate facies crop out along the platform margin in the vicinity of bosanska krupa, ključ, w and s of banjaluka, and also in the area of the kupres polje and prozor (papeš, 1975, 1985; mojičević et al., 1979; marinković & ahac, 1980; sofilj et al., 1980; vrhovčić & mojičević, 1983). middle jurassic carbonates – thick-layered mudstones with interbeds of fossiliferous wackestones–packstones, have been found in the kordun region n of slunj with continuation in a sw direction towards bihać and in the surroundings of ključ. they contain characteristic microfossil benthic foraminiferal taxa: mesoendothyra croatica gušić, gutnicella cayeuxi (lucas) in alenian and bajocian, paleopfenderina salernitana (sartoni & crescenti) and satorina apuliensis fourcade & chorowicz in bathonian, as well as algae selliporella donzellii sartoni & crescenti in bajocian and bathonian. the shallow marine middle jurassic deposits in the back-reef environments of the platform margin in slovenia are generally marked by two types of carbonates: mud-supported limestones and oolitic limestones, fig. 27 recent position of the middle jurassic ne platform margin deposits. legend: 1) emerged areas; 2) inner platform deposits; 3) ooid grainstones; 4) slope to basin deposits. n 212 geologia croatica 55/2 213dragičević & velić: the northeastern margin of the adriatic carbonate platform and some significant occurrences of late-diagenetic dolomites (buser, 1969, 1987; buser et al., 1967; orehek & ogorelec, 1981; dozet & šribar, 1998a; dozet, 2000a, b). of special importance are the occurrences of oolitic limestones of the middle jurassic and the lower part of the late jurassic of the platform margin. according to dozet (2000a, b) they locally reach the thickness of approximately 450 to 500 m. these limestones have characteristics of the carbonate platform margin. their long-lasting deposition and duration were the result of relative stability of palaeoenvironments in this part of the platform margin through the jurassic period. at the platform margin se of the study area, the platform carbonate facies of middle jurassic age are known in mt. prenj (mojičević & laušević, 1971) and east of nevesinje in herzegovina (mojičević & laušević, 1969; mojičević & tomić, 1982a), also in the piva area and in the vicinity of nikšić and žabljak in montenegro (vujisić, 1972; mirković et al., 1979; mirković & mirković, 1987). this se part of the platform margin in the dogger was also marked by the predominance of two types of limestone – different mudstone varieties and oolitic grainstones with subordinate late-diagenetic dolomites. in conclusion, it can be stated that, the platform margin in the middle jurassic was dominated by oolitic limestones in the similar manner to that in the early jurassic. 2.3.1.4. upper jurassic in the geological history of the adcp, i.e. through the jurassic and cretaceous, its ne margin was the most prominent margin and most clearly marked during the late jurassic, especially in the kimmeridgian and tithonian. generally, two facies groups were differentiated. the first one is composed of carbonates formed in back-reef environments close to the platform margin, in high energy shallows and in restricted shallows and lagoons, while the second group belongs to the platform barrier reefs (fig. 28). in the first group there is the alternation of fossiliferous algal–foraminiferal (sporadically also oncolitic) mudstones, wackestones and packstones, and more rarely occurring oolitic, intraclastic and tempestitic fossiliferous packstones–grainstones. they were deposited in restricted subtidal shallows, lagoons and fore-reef environments with clear characteristics of shallowing upward cycles. these limestones contain late-diagenetic dolomites, usually in the form of thin interbeds and in alternation with limestones, but there are also lenses and massive dolomite bodies of tens of km-sized bands. limestones contain rich microfossil assemblages which determine the stratigraphic range of the entire late jurassic. the most important are algal species salpingoporella sellii (crescenti), clypeina jurassica favre and campbelliella striata (carozzi), and foraminifera kurnubia palastiniensis henson, labyrinthina mirabilis weynschenk, parurgonina caelinensis cuvillier et al. and neokilianina rahonensis foury & vincent. in the study area this facies can be traced from the surroundings of slunj in croatia (korolija et al., 1980; šparica, 1981), through the area of bihać in nw bosnia (polšak et al., 1977) and also bosanska krupa (mojičević et al., 1978), sanski most (đerković et al., 1976), from banjaluka (mojičević et al., 1977) to jajce (marinković & ahac, 1980) and to the kupres polje in the central bosnia (vujnović, 1980). in the marginal part of the adcp in slovenia, malm carbonate facies with these characteristics are not widely distributed. in the se parts of the study area, they were determined at mts. prenj and velež in herzegovina (mojičević & laušević, 1971; mojičević & tomić, 1982b), while mostly younger malm was found in montenegro in the vicinity of nikšić (vujisić, 1972) and žabljak (mirković & mirković, 1987). the second group of upper jurassic facies is represented by the coral–hydrozoan barrier reefs. these markedly marginal platform facies are the most prominent organic build-ups on the adcp in its entire geological history. they remain relatively well preserved and extend from western slovenia, south of the slovenian trough along the northern, north-eastern and eastern margin of the platform all the way to southern montenegro and northern albania, to the krasta–cukali–budva trough (fig. 28). these biolithite build-ups are composed both of the complete skeletons and fragments of reef-building organisms including hydrozoans, especially stromatoporoids, bryozoans, sponges, corals, calcareous algae, gastropods, bivalves, echinoids, foraminifera, etc. (fig. 3). the complete palaeontological study of these fossils was not performed, except for the corals (turnšek, 1997; turnšek et al., 1981). in the literature, most papers dealing with stratigraphy usually contain quotations of the fossils from the mentioned macrofossil groups, e.g. the stromatoporoids such as ellipsactinia, sphaeractinia, actinostromina, parastromatopora, chaetetids bauneia, chaetetopsis, corals amphistraea, stylosmilia, montlivaltia, thecosmilia, gastropods ptygmatis, nerinea, phaneroptyxis, cryptoplocus, and bivalves diceras, etc. within the reef facies, microfossils occur sporadically, including benthic foraminifera kurnubia palastiniensis henson, labyrinthina mirabilis weynschenk, parurgonina caelinensis cuvillier, foury & pignatti-morano, neokilianina rahonensis foury & vincent and algae clypeina jurassica favre, campbelliella striata (carozzi) and c. milesi (radoičić). upper jurassic barrier reefs were found in the broader surroundings of karlovac in croatia (bukovac et al., 1974, 1984). significant extension of these reefs has been known along the platform margin from bosanska krupa in nw bosnia (đerković et al., 1976; moji212 geologia croatica 55/2 213dragičević & velić: the northeastern margin of the adriatic carbonate platform čević et al., 1977, 1978; jelaska, 1987) southeastward through central bosnia (marinković & ahac, 1980; vujnović, 1980; živanović et al., 1971; papeš, 1972) to northern herzegovina (sofilj & živanović, 1979) and south of sarajevo (jovanović et al., 1977). the continuation of reef facies of the platform margin is traced through herzegovina, east of velež (mojičević & tomić, 1982a) and nevesinje (mojičević & laušević, 1969) to the piva area in montenegro (mirković et al., 1979). they have been preserved in northern montenegro – in the vicinity of žabljak (mirković & mirković, 1987; mirković & vujisić, 1989) and on rumija mt. (mirković et al., 1977). between these two regions, in northern albania, there are no reliable data. nevertheless, from the available literature (peza & peza, 1994) the existence of reef facies, either in the form of barrier reefs or patch reefs, can also be supposed for that marginal part of the platform n and nw of the cukali–krasta–budva trough. the malmian coral–hydrozoan barrier reefs also extended along the nw margin of the adcp in slovenia, where they were most carefully palaeontologically investigated (e.g. turnšek, 1966, 1997; turnšek & buser, 1974; turnšek et al., 1981). they strike from novo mesto (pleničar et al., 1976) west towards trnovski gozd mt. and the tolmin environs (buser, 1968, 1969, 1987; buser et al., 1967; turnšek, 1997; turnšek et al., 1981; dozet & šribar, 1998a). these barrier reefs were rapidly subjected to abrasion and fragmentation while extant, due to the action of oceanic waves and currents, and also due to the influence of synsedimentary tectonics and earthquakes. this is the most important reason for the discontinuous appearance of this unit that strikes along the ne margin of the adcp. these destructive processes provided the sources of different materials – blocks and clasts that were further crushed and redeposited in the back-reef shallows towards the inner part of the platform, but mostly at the platform slope, so they are found as fragments within the slope sediments and/or in the proximal basin sediments. 2.3.1.5. lower cretaceous lower cretaceous platform carbonates crop out in the platform marginal area from žumberak to the kupres polje. they are known in the vicinity of karlovac (bukovac et al., 1974), in the kordun area (korolija et al., 1980; šparica, 1981) and in the surroundings of bihać (polšak et al., 1977). they were also documented in nw bosnia, in the area of bosanska krupa (mojičević et al., 1978), sanski fig. 28 recent position of the kimmeridgian and tithonian ne platform margin deposits. legend: 1) inner platform deposits; 2) coral–hydrozoan barrier reefs; 3) ooid grainstones; 4) slope to basin deposits. n 214 geologia croatica 55/2 215dragičević & velić: the northeastern margin of the adriatic carbonate platform most (đerković et al., 1976) and in the vicinity of ključ to the se (vrhovčić et al., 1983), in manjača and on both slopes of the vrbas river canyon (fig. 5), in the broader region of jajce (marinković & ahac, 1980), on vlašić mt., in the canyon of the janj river and north west and south-east of the kupres polje (papeš, 1972, 1985; vujnović, 1980). some parts of the platform were occasionally emerged (fig. 29). the lower cretaceous carbonates are mostly represented by different varieties of limestones, mostly mudstones, fossiliferous wackestones and packstones. in the neocomian and older barremian, the thicklayered to massive mudstones and fossiliferous mudstones prevail. younger barremian and aptian deposits are characterised by orbitolinid and salpingoporella wackestones, as well as interbeds of rudist coquinas. sporadically there are coral–hydrozoan–rudist biolithite build-ups which originated from patch-reefs (fig. 30). in the albian, orbitolinid wackestones, locally also grainstones (tempestites) are prominent, together with miliolid wackestones/packstones as well as bivalves and gastropod coquinas and floatstones. apart from the limestones, throughout the entire column of lower cretaceous sediments there are interbeds and lenses of late-diagenetic dolomites. lower cretaceous deposits are rich in fossils, especially calcareous algae and foraminifera (particularly orbitolinids). frequently entire beds of wackestones, packstones or tempestite grainstones are composed of orbitolinid shells. because of the rich fossil assemblages in which orbitolinids form the framework of biostratigraphic zonation, the lower cretaceous of the study area has been stratigraphically subdivided relatively well. only the most important index fossils will be mentioned here: protopeneroplis ultragranulata (gorbatchik) in berriasian, vercorsella camposaurii (sartoni & crescenti), v. tenuis (velić & gušić), campanellulla capuensis de castro and clypeina solkani conrad & radoičić in valanginian and hauterivian, salpingoporella muehlbergii lorenz, rectodictyoconus giganteus schroeder and palorbitolina lenticularis (blumenbach) in barremian, p. lenticularis, praeorbitolina cormyi schroeder, p. wienandsi schroeder and mesorbitolina lotzei schroeder, archalveolina reicheli (de castro) and very abundant salpingoporella dinarica radoičić in aptian, mesorbitolina parva douglass and m. texana (roemer) in late aptian and early albian, mesorbitolina subconcava leymerie and m. pervia douglass in early albian and salpingoporella turgida (radoičić), valdanchella dercourti (decrouez & moullade), neoiraquia insolita (decrouez & moullade) and n. convexa danilova in late albian. barremian and lower aptian floatstones, coquinas and occasionfig. 29 recent position of the jurassic–cretaceous transition ne platform margin deposits. legend: 1) emerged areas; 2) inner platform carbonate deposits; 3) slope to basin deposits. n 214 geologia croatica 55/2 215dragičević & velić: the northeastern margin of the adriatic carbonate platform ally biolithites contain numerous rudists of the genera requienia, toucasia, caprina and praeradiolites, together with remains of bryozoans, hydrozoans, corals and molluscs. the platform margin could be traced in a se direction through herzegovina and montenegro with the same facies characteristics as in croatia and bosnia. a similar situation occurs in southeastern slovenia, where, surrounded by subtidal, lagoonal restricted environments, barremian–aptian biolithites and patch-reefs with rudists, corals, hetetids, bryozoans etc. were discovered (bukovac et al., 1984; dozet & šribar, 1998b). in western slovenia the reef build-ups of valanginian and barremian–aptian age (turnšek & buser, 1974; buser, 1987; turnšek, 1997), could be the remains of platform margin barrier reefs (fig. 30). 2.3.1.6. upper cretaceous there are sparse outcrops of the older upper cretaceous sediments at the very margin of the platform. most of the marginal area from žumberak in croatia to the bosna river valley and to the kupres polje in bosnia and herzegovina was mostly emergent at that time. that is why these sediments in the study area are displaced in a s–sw direction, from the margin towards the inner parts of the platform. their basic facies characteristics are more or less the same as in other parts of the adcp. in the explored area they were determined in the surroundings of karlovac (bukovac et al., 1984), n and se of slunj (korolija et al., 1980; šparica, 1981), in the vicinity of bihać (polšak et al., 1977), in manjača, in the jajce area, on vlašić mt. (marinković & ahac, 1980; živanović et al., 1971; dragičević, 1987) and north of the kupres polje (vujnović, 1980). in the cenomanian, shallower subtidal and peritidal environments dominated with numerous communities and colonies of rudists. there were pelagic influences from time to time, and sequences composed of alternations of rudist floatstones, coquinas, rudstones and foraminiferal wackestones to grainstones frequently containing interbeds of platy limestones, mudstones to fossiliferous wackestones with calcisphaeras, globotruncanids and globigerinids, and occasionally with nodules and lenses of chert. they were found in the kordun area, on lička plješevica mt. and in the surroundings of bihać (polšak et al., 1978), but they also most probably extend in a se direction. this is the consequence of the upper cenomanian/lower turonian platform drowning that was determined more or less over the entire platform area (e.g. gušić & jelaska, 1990, 1993; jelaska et al., 1994; jurkovšek et al., 1996; korbar et al., 2001). there are only scarce data on the development of turonian deposits. the rudist limestones above the calcisphaera limestones in kordun, lička plješevica mt. and in the area of bihać (polšak et al., 1977, 1978; šparica, 1981) are of turonian age. this pertains to the inner parts of the platform sw of its margin. the platform margin was, in most of the study area, from fig. 30 recent position of the aptian to cenomanian ne platform margin deposits. legend: 1) inner platform carbonate deposits; 2) biolitiths (patch-reefs); 3) slope to basin deposits. n 216 geologia croatica 55/2 217dragičević & velić: the northeastern margin of the adriatic carbonate platform žumberak to kupres polje and to the bosna river valley, emerged from the late albian or early cenomanian to the early santonian. exceptions are only found at some localities in the vicinity of karlovac (fig. 4; šparica, 1981), in manjača (marinković & ahac, 1980; mojičević et al., 1977), east of jajce (fig. 18) and in the vlašić mt. (fig. 20), where middle and upper cenomanian limestones were determined. the karstified lower cretaceous limestones south of banjaluka and in the surroundings of jajce are directly covered by the youngest cretaceous rudist limestones of upper santonian to campanian age. these are biohermal biolithites, frequently of the barrier reef type (fig. 16), but also rudist rudstones, coquinas, foraminiferal calcarenites, and sporadically rudist floatstones and foraminiferal wackestones. towards the younger levels, the ratio of rudist fragments and carbonate clasts in general diminishes, grains become smaller and the ratio of the clastic components gradually rises all the way to the typical flysch facies of the campanian–maastrichtian age. in žumberak, the slunj area, in grmeč mt., n of jajce and in vlašić mt., rudist biolithite complexes of the platform margin of the santonian, campanian and maastrichtian age are mentioned by polšak (1981), while šparica (1981) describes them at several localities in kordun as being generally of senonian age. upper cretaceous carbonates are markedly fossiliferous. the rudists predominate, and other important macrofossils are chondrodonts, gastropods, and in the biolithites corals, corallinaceans, bryozoans, echinoids, etc. but foraminifera are the most important for stratigraphic subdivision. only several of the index species and some more important rudist genera will be mentioned. the following foraminifera were determined in the cenomanian deposits: orbitolina (conicorbitolina) conica (d’archiac), chrysalidina gradata d’orbigny, broeckina (pastrikella) balcanica cherchi et al., pseudolituonella reicheli marie, pseudorhapydionina dubia de castro and p. laurinensis de castro etc., together with rudists of the genera radiolites, caprina, neocaprina, sauvagesia, ichthyosarcolites, gyropleura, monopleura, preradiolites, chondrodonts chondrodonta joannae (choffat), ch. joannae angusta (schubert) and ch. munsoni hill, gastropods (mostly of genus nerinea) etc. there are no foraminifera that are exactly the index species for the turonian, but important ones are moncharmontia apenninica (de castro) and pseudocyclammina sphaeroidea gendrot, together with rudists – tiny radiolitides and those of the genera biradiolites, distefanella, sauvagesia, durania etc. (polšak et al., 1978). foraminiferal assemblages containing the species scandonea samnitica de castro, pseudorhafig. 31 recent position of the santonian and maastrichtian ne platform margin deposits. legend: 1) inner platform carbonate deposits; 2) carbonate–clastic deposits of intraplatform troughs, platform slope and basin. n 216 geologia croatica 55/2 217dragičević & velić: the northeastern margin of the adriatic carbonate platform pydionina mediterranea (de castro), accordiella conica farinacci, dicyclina schlumbergeri munier-chalmas, keramosphaerina tergestina stache and murgella lata luperto-sinni define the santonian–campanian age of the rudist limestones above the albian/cenomanian–early santonian emersion. they contain a mass of rudist shells of different genera – radiolites, gorjanovicia, biradiolites, bournonia, hippurites etc. in maastrichtian–palaeocene debrites se of banjaluka dragičević (1987) has also determined maastrichtian species vaccinites vesiculosus (woodward) and v. conicus adriaticus sladićtrifunović. upper cretaceous carbonates close to the platform margin se of central bosnia, including local occurrences of biolithite build-ups, were found in the prenj and velež mts. (mojičević & tomić, 1982a), in the vicinity of nevesinje (mojičević & laušević, 1969) and southeastward, in herzegovina, as well as west of the piva area (mirković et al., 1979), in the vicinity of nikšić (vujisić, 1972) and on maganik mt. (kalezić & mirković, 1970). there are no available detailed data of lithofacies and stratigraphy but, according to the publications, similar facies development as in the described terrains of croatia and bosnia with a stratigraphic range from younger cenomanian to the campanian can be supposed. along the platform margin in slovenia, upper cretaceous carbonates are exposed between gorica and tolmin (buser, 1987). there was an emersion phase with bauxite occurrences between the cenomanian and senonian limestones, at the same level as near karlovac (dubravčani, fig. 4) and jajce (ravanac, fig. 18). in trnovski gozd mt. (buser, 1968), nanos mt., and areas of notranjska (buser et al., 1967), suha krajina (buser, 1969) and novo mesto (pleničar et al., 1976), rudist limestones, most likely not younger than cenomanian or early turonian, were closest to the platform margin. 2.3.2. slope and basin facies of the ne margin of the platform in the investigated region from žumberak to central bosnia, slope facies on the ne slopes of the platform, as well as basinal facies extending in the direction of the open-marine tethys are fragmentary and only crop out sporadically. in the region to the south-east, in herzegovina, montenegro and northern albania, and also in the north-west, in slovenia, they crop out over larger areas and with regional strikes. 2.3.2.1. lower and middle jurassic slope to basinal limestones in direct contact with platform limestones of the uppermost lower jurassic and middle jurassic age have been known near sošice in žumberak (radoičić, 1966; gušić & babić, 1970; pleničar et al., 1976; bucković et al., 2001) and also in the samobor mts. (šikić & basch, 1975; šikić et al., 1978; fig. 2). their basal parts are composed of oolitic limestones with radiolarian chert interbeds, followed by a sequence of alternating mudstones, fossiliferous mudstones/wackestones and cherts (šikić et al., 1979). locally, e.g. south of karlovac (in barilović and sića), dark and well-bedded mostly fossiliferous lower jurassic wackestones were determined. they were deposited in the platform slope environments wherein the slope benthos and pelagic microorganisms are mixed with the fossils, lithoclasts and bioclasts originating from the platform margin (gušić, 1969). in kordun and in western and central bosnia, data on slope deposits of the early and middle jurassic are very poor. the clastic–carbonate sediments (marls and shales with limestone lenses and thicker tuff intercalations) near veljun in kordun were interpreted by šparica (1981) as basinal deposits of the early jurassic. the same author also describes olistoliths of basinal limestones (limestones with “filaments” and radiolarians) of early and middle jurassic age within shales of the “magmatic–sedimentary complex” in the banija area. in the subotica creek profile w of banjaluka (fig. 9) jelaska (1987) described the slope breccias with “packages” of massive mudstones that unconformably overlie middle liassic oolitic limestones, characterised by slumping and the chaotic arrangement of angular lithofragments in the micrite matrix. these rocks are mostly of upper lias age and contain typical “slope” foraminifera (involutinids and “vidalinas”). the breccia is overlain by upper jurassic hydrozoan reef limestones. this breccia unit can be compared with similar breccias containing fragments of slope limestones deposited in deeper environments that were found near sošice in žumberak and explained by gušić & babić (1970) as being connected to tectonics on the early–middle jurassic boundary. early jurassic basinal deposits closest to the platform in šehitluci (banjaluka) were mentioned by blanchet (1975). mojičević et al. (1977) and živanović et al. (1971) described clastic–carbonate basinal sequences of generally jurassic or late jurassic age in the area of banjaluka and zenica. the fossil content and therefore the palaeontological documentation of these sediments is poor. only involutina liassica (jones) is an index species of early jurassic age, while ophthalmidium martanum (farinacci), globochaete alpina lombard, frondicularia sp., lenticulina sp., cristellaria sp., saccocoma sp., globigerinids, radiolarians and “filaments” are of environmental significance. there is significantly more data regarding the slope, and especially the basinal sequences of the se marginal parts of the platform (figs. 25–27). the platy limestones of the lower and middle jurassic are found north and south of prozor (sofilj & živanović, 1979), platy and clayey limestones with ammonites in crvanj mt. in ne herzegovina (mojičević & tomić, 1982a, b), grey and red platy clayey limestones with cherts 218 geologia croatica 55/2 219dragičević & velić: the northeastern margin of the adriatic carbonate platform and ammonites east of nevesinje, in the surroundings of gacko (mojičević & laušević, 1969, 1973; mirković, 1980; mirković et al., 1979). in montenegro, in the piva area, the red and grey clayey limestones with cherts, containing ammonites and pelagic microfauna, were described by mirković (1980) and mirković et al. (1979). lower jurassic red platy clayey limestones with ammonites and middle jurassic limestones with filaments and globigerinids in the dogger were described from the vojnik and durmitor mts., as well as in the broader surroundings of žabljak (vujisić, 1972, 1975; mirković & mirković, 1987; mirković & vujisić, 1989; živaljević et al., 1989). finally, deep marine facies of the early and middle jurassic are known from the cukali–budva trough, occasionally represented by reddish limestones with ammonites (mirković et al., 1978). the deep marine lower and middle jurassic sequences are also known in western slovenia (figs. 25–27), north of the adcp margin – in the slovenian trough (kuščer et al., 1974; buser, 1986, 1987; jurkovšek et al., 1988/89; ogorelec & dozet, 1997). the lower jurassic is represented by platy mudstones with lenses and nodules of chert, locally containing shale and marl, and the middle jurassic sequence is composed of the alternation of shale and chert. to the east, close to the northern margin of the platform in žumberak there are no outcrops of slope and/or basinal sequences of the lower and middle jurassic. originally they probably existed but were affected by later events – either being eroded or tectonically reduced or covered with younger sediments. 2.3.2.2. upper jurassic slope facies of the upper jurassic are represented by carbonate sequences, and basinal facies by both carbonate and clastic–carbonate (“flysch”) sequences. finegrained muddy limestones, among which are the “calpionella limestones” (mudstones, fossiliferous mudstones to wackestones) alternating with calcarenites and cherts are known from sošice in žumberak (radoičić, 1966; pleničar et al., 1976; bucković et al., 2001) and from the samobor mts. (babić, 1973; šikić & basch, 1975; šikić et al., 1979). “calpionella limestones” have also been found in the vicinity of ozalj (bukovac et al., 1984). these are typical basinal sediments that can be traced in a se direction through kordun and banovina (korolija et al., 1981; šparica, 1981). in the vicinity of karlovac (dugaresa, martinšćak hill, barilović), slope facies of the late jurassic were also determined (bukovac et al., 1974; šparica, 1981), mostly consisting of fine-grained mud-supported limestones with nodules and occasionally with interbeds of chert. these limestones contain lithoand bioclasts that originated from the platform shallows, together with slope benthic and pelagic microfauna. there are also sporadic occurrences of detrital limestones (calcarenite) composed of particles from the platform carbonates transported down the slope by occasional turbidity currents. interbeds and lenses of such calcarenites with clasts from the shallow marine facies are also found in the basinal facies. in nw bosnia, in the surroundings of bihać, the “lemeš deposits” are known. these are platy limestones with chert and sporadic ammonites, containing interbeds of black kerogeneous schisty laminites of kimmeridgian and early tithonian age (polšak et al., 1978). these are deposits of a shallower marine trough which extended from the ne margin into the central parts of the adcp (fig. 28; see discussion in velić et al., 2002b). this trough was not deep enough for deep marine, basinal sedimentation to develop. further in an e and se direction, close to the platform margin in the banjaluka and zenica area, deep marine, basinal sediments (“flyschs”) of the bosnian trough were proven biostratigraphically by calpionellids of tithonian to valanginian age (živanović et al., 1971; blanchet, 1975; mojičević et al., 1977). south of kupres, dragičević (1987) described limestones, mostly mudstones and floatstones, deposited in fore-reef shallows, as the products of destruction of hydrozoan reefs. apart from clasts of the reefbuilding organisms, they contain benthic foraminifera and numerous calpionellids. more detailed study was prevented by the terrain being covered, but it can be assumed that this is the slope facies of tithonian to valangian age. this autochthonous fossil content is exclusively composed of calpionellids, radiolarians, calcisphaers and ammonites. within the “lemeš deposits” polšak et al. (1978) mentioned the ammonite genera perisphinctes and virgatosphinctes. among the calpionellids, those specifically determined were calpionella alpina lorenz and c. elliptica cadish. in the samobor mts. babić (1973) performed a detailed biostratigraphic zonation and described a significant calpionellid assemblage with taxa of tithonian to valanginian age. apart from the ones mentioned above, he also quotes the following more important species: crasicollaria intermedia (duran-delga), c. parvula remane, remaniella cadischiana (colom), tintinnopsella carpathica (murgeanu & filipescu), t. longa (colom), calpionellopsis simplex (colom), c. oblonga (cadish), cadosina lapidosa vogler and calpionellites darderi (colom). in herzegovina and montenegro, in the basinal clastic–carbonate sediments – the “flyschs” and the “diabase–chert formation” a tithonian–berriasian–valanginian age was determined by calpionellids (mojičević & laušević, 1973; kalezić et al., 1973; antonijević et al., 1973; mirković, 1980; mirković & mirković, 1987; živaljević et al., 1989; radoičić, 1989). this was also done in the north-west, in the slovenian trough (babić, 1980; buser, 1986; jurkovšek et al., 1988/89). 218 geologia croatica 55/2 219dragičević & velić: the northeastern margin of the adriatic carbonate platform 2.3.2.3. lower cretaceous outcrops of slope or basinal facies of lower cretaceous age close to the ne margin of the adcp were only locally determined. it is clear that part of the “calpionella limestones” at every location mentioned above also belong to the oldest cretaceous – berriasian and valanginian. in this way, the “calpionella limestones” in žumberak are followed by younger slope-to-basin sediments of hauterivian, albian and cenomanian age (babić, 1974). close to the žumberak area, near krško in se slovenia, marjanac & marjanac (1987) determined aptian and albian slope deposits represented by shales with intercalations of thin mudstones, tuffitic limestones and debrites. upper albian flysch comprises sandstones, mudstones, marls and mud supported debrites. in the banovina area, šparica (1981) described the basinal carbonate–clastic sediments of turbidite characteristics containing a shallow marine lower cretaceous benthos (foraminifera and calcareous algae) in clasts of the calcarenite intervals and pelagic microfossils including calpionellids, calcisphaeres and hedbergellas in the limestones, marls and shales. parts of the jurassic–cretaceous flysch of the bosnian trough in the vicinity of banjaluka and zenica (blanchet, 1975; mojičević et al., 1977; živanović et al., 1971) are also most likely to belong to the early cretaceous. in the area s of sarajevo, the clastic–carbonate sediments of the basinal lower cretaceous are exposed on the slopes of the igman, bjelašnica and visočica mts. they were also determined in the region all the way to the upstream part of the neretva river valley (jovanović et al., 1977; mojičević & tomić, 1982a). in montenegro, they were found e of žabljak (mirković & vujisić, 1989). the cukali–budva trough is mostly filled with siliceous sediments – cherts and radiolarites in general (antonijević et al., 1973), containing lenses and interbeds of detrital limestones and breccias with clasts of platform carbonates and fossils, which is usual in the turbidite facies. in the nw part of the platform, on the slope towards the slovenian trough, lower cretaceous flysch deposits are characterised by an alternation of shales, cherts, platy limestones, calcarenites and breccias (buser, 1986, 1989; jurkovšek et al., 1988/89). 2.3.2.4. upper cretaceous the recent regional distribution of the upper cretaceous slope and basin sediments enables good contouring of the border with the platform shallow marine environments during the time of deposition. it also enables the reliable palaeogeographic description of the final disintegration of the adcp which happened during the late cretaceous. these slope-to-basin sediments are mostly defined as flysch, and there was an almost continuous zone extending either at or close to the ne margin of the platform from the slovenian trough to the cukali–budva trough (fig. 31). moreover, in a general transgressive trend, the youngest horizons of these sediments had not only covered significant parts of the older marginal platform sequences, but were also deposited in several smaller troughs which were formed sw of the platform margin by strong tectonic compression during the late cretaceous (dragičević, 1987). this is discussed in more detail below in section 3. the slope and basin sediments of the upper cretaceous are developed almost continuously along the strike of the ne platform margin. they are known from žumberak, the karlovac area, kordun, areas of bihać, bosanska krupa, ključ, banjaluka, jajce and vlašić mt. to the areas both n and s of the kupres polje. within the upper cretaceous slope-to-basin carbonate–clastic or flysch sediments there are two stratigraphic sequences – an older one of cenomanian–turonian age and a younger one of santonian–campanian–maastrichtian age (sokač, 1964; korolija et al., 1980, 1981; šparica, 1981; marjanac & marjanac, 1987; mrinjek, 1988a, b). jelaska et al. (1969) and jelaska (1987) described these sediments, including basinal limestones of the “scaglia” type, at various late cretaceous horizons. in kordun (cetingrad area) cenomanian–turonian flysch deposits that are closest to the ne platform margin are composed of turbidite sequences, mostly of marls alternating with fine-grained sandstones, rarely with calcarenites and breccias (sokač, 1964; korolija et al., 1980, 1981; šparica, 1981; mrinjek, 1988a, b). apart from these lithologic members, sokač (1964) also mentioned lenses of thin-layered limestones. the main constituents of the calcarenites and breccias are lithoclasts and macrofossil bioclasts, as well as a lot of fragmented and abraded cenomanian orbitolinids. due to the mass occurrences of redeposited orbitolinids, these sediments were frequently named the “orbitolinid cretaceous”. as there are no records of autochthonous fossils, a late albian to early turonian time span has been proposed. there are numerous data on composition, age, mechanisms and environments of deposition of younger, santonian–campanian–maastrichtian carbonate–clastic sediments at the ne margin of the platform. the regional setting of this unit was analysed in the works of jelaska et al. (1969), polšak (1981), šparica (1981) and jelaska (1987). basinal sediments of the late cretaceous are represented by mostly platy limestones with globotruncanids (the “scaglia” type limestones) that are found interbedded within the distal parts of the flysch sequences or alternating with flysch. these are thin-layered and platy, grey and reddish, frequently clayey mudstones and fossiliferous mudstones with nodules and interbeds of chert, containing lots of pelagic organisms, primarily globotruncanids followed by globigerinids, heterohelicids, radiolarians etc. although these sediments are mostly covered by tertiary and quaternary deposits, they were identified at numerous locations from 220 geologia croatica 55/2 221dragičević & velić: the northeastern margin of the adriatic carbonate platform žumberak all the way to the valley of the river bosna (fig. 31). only the areas closest to the platform margin will be described from nw to se. these deposits were investigated in central croatia – žumberak, karlovac area, banovina and kordun (sokač, 1964; zupanič, 1976; babić & zupanič, 1976; šparica, 1981; mrinjek, 1988a, b), in western bosnia (jelaska et al., 1969; šparica, 1981; jelaska, 1987) and in central bosnia (tomić, 1985; dragičević, 1987). further in a southeastern direction, upper cretaceous slope and basinal sediments are found alongside the recent position of the platform margin in bosnia – on the southern slopes of. visočica mt and in the upstream part of the neretva river valley, with a continuation through ne herzegovina and montenegro (the “durmitor flysch”) to northern albania (fig. 31). in the northwest, in the slovenian trough, flysch sedimentation continued from the albian into the cenomanian, platy reddish limestones with interbeds of red marls were deposited in the turonian, during the coniacian–maastrichtian time span, platy “volča” limestones with chert were deposited, and then flysch again in the maastrichtian (pleničar, 1958; šribar, 1965; ogorelec et al., 1976; pavšič, 1977; buser et al., 1982; marjanac & marjanac, 1987; buser, 1989). 3. geodynamic evolution and palaeogeography of the northeastern margin of the adriatic carbonate platform during the jurassic and cretaceous the geological history of the platform margin area during the permian–palaeogene time span can be interpreted through six evolutionary phases. each was characterised by specific palaeogeographic relationships and is a continuation of the preceding phase. the phases are: (1) permian to the lower jurassic as the pre-individualisation period, (2) pliensbachian to toarcian – time of individualisation of the platform during the lower jurassic, (3) toarcian to the late albian – a relatively stable period of the platform shallow water regime, (4) late albian/early cenomanian to santonian – the phase of significant tectonic events which caused regression, emersion and transgression, i.e. the beginning of platform disintegration, (5) santonian transgression and continuation of platform disintegration, (6) campanian gradual flooding of the platform margin area with the peak of the transgression during the maastrichtian and palaeocene. 3.1. pre-individualisation relationships from permian to lias during the late permian and early to middle triassic, the study area was part of the shallow marine carbonate shelf, i.e. epeiric carbonate platform of the gondwana. both within the investigated area and further afield (jajce–šipovo, kupres, eastern bosnia) several smaller carbonate platforms already existed within this shelf in the late permian, and they were later “incorporated” in the thick sequence of carbonate rocks which continuously overlaid them through the triassic. the early triassic was characterised by an alternation of shallow water carbonate and siliciclastic deposition. through the middle triassic significant masses of shallow water sediments, mostly algal limestones were deposited. from the anisian to the carnian (culminating in the ladinian) there were complex rifting processes with submarine volcanic activity. dominant rock types were diabase and spilite accompanied by clastics, pyroclastics and limestones. due to the constant tectonic activity there was pronounced diversification of depositional environments and lithofacies. at the ladinian–carnian transition some morphologically elevated areas were emerged and covered by laterite bauxites (e.g. ljuša locality south of jajce). during the late triassic, extensive and relatively stable carbonate sedimentation of a markedly platform character was established, but without a clearly defined margin towards the opened oceanic, basinal domains. prevailing facies were of the shallow marine, intertidal and supratidal environments wherein two regionally well known formations were deposited – the dachstein limestones and the “hauptdolomit” (“main dolomite”) which are widely distributed in the perimediterranean region. there were no signs of more important events in the area of the future platform margin. in fact, these upper triassic facies/formations are widely distributed over the wider area, i.e. also outside the area of the future adcp during the jurassic and cretaceous. the “hauptdolomit” is conformably overlain by the lower jurassic carbonates, the facies differentiation of which allows interpretation of various depositional environments. this is most likely the beginning of tectonic movements that caused significant changes in the palaeogeography during the early jurassic, since in the early lias the platform margin was still not pronounced. in areas where it was going to be formed (during the late pliensbachian and toarcian) grain-supported and oolitic limestones were deposited within sand bar environments. in more restricted environments, the subtidal algal–foraminiferal wackestones, brachiopod and lithiotid floatstones and tempestite coquinas were deposited (fig. 25). 3.2. individualisation of the platform in the early jurassic significant palaeogeographic changes that took place in the periadriatic area during the early jurassic were the direct consequence of regional extensional movements with rifting connected with the beginning of the opening of the atlantic ocean. this was the time of separation of the previously united shallow marine carbonate area of the adria microplate into several isolated carbonate platforms. the adriatic carbonate platform was 220 geologia croatica 55/2 221dragičević & velić: the northeastern margin of the adriatic carbonate platform separated from the apulian and apenninic platforms by the connection of the ionian and belluno pelagic basins (e.g. bernoulli, 1971; jelaska, 1973; zappaterra, 1990, 1994; gambini & tozzi, 1996; grandić et al., 1999). the most important consequence of this tectonic activity and palaeogeographic changes was the individualization of the adriatic carbonate platform and formation of its sw and ne margins and slopes. these events were reflected in the ne margin as identified in the žumberak area (gušić & babić, 1970; šikić & basch, 1975; šikić et al., 1979). extensional faulting along an approximately nw–se line, resulted in the gradual subsidence and drowning of the ne part of the former shallow water environments. this was a process which led to the formation of the platform slope. areas where platform carbonates were previously deposited became the sites of slope to basin deep water carbonate sedimentation. in the samobor mts. lower liassic shallow marine carbonates were covered by middle to upper liassic and middle jurassic deep marine slope to basinal carbonates with pelagic microfossils. the lack of shallow marine fossil assemblages, both macrofossils (e.g. lithiotids or brachiopods) and large lituolid foraminifera, especially orbitopsellas, indicate that formation of the ne slope of the adcp started even earlier, in the late sinemurian (latest early lias). southwestward on the carbonate platform area, shallow water sedimentation continued. at the same time the very platform margin was emerged, so that the shallow marine platform area sw of the margin was separated by the land from the basinal deep marine area to the ne. the emergence lasted from the latest pliensbachian to the kimmeridgian, and a hiatus was determined in the surroundings of karlovac (bukovac et al., 1974), in the kordun area, and in nw bosnia (šparica, 1981). this was either a linear archipelago or a united larger land area extending from trnovski gozd mt. (nikler, 1978), through the suha krajina area in slovenija (buser, 1969; pleničar, et al., 1976; dozet, 1994), and through žumberak, the karlovac area (bukovac et al., 1974, 1984; šparica, 1981; dragičević & velić, 1994) and kordun in croatia all the way to nw bosnia (šparica, 1981). in the direction of the south-east, in bosnia, there was a larger island or several islands in the region from bosanska krupa to banjaluka (jelaska, 1987), in manjača and towards jajce (marinković & ahac, 1980). the existence of land or islands exactly along the margin in central bosnia is confirmed by the hiatus from the late triassic/early jurassic to the late jurassic which was determined north of the kupres polje (vujnović, 1980). tectonic reductions and coverage of the marginal area with younger sediments make continuous tracing of the early jurassic palaeogeographic events and changes along the platform margin impossible. mostly oolitic, intraclastic and bioclastic limestones were deposited in the shallows around island(s). they were formed from the large accumulations of carbonate sands of the platform marginal area. in the external marginal parts which were exposed to mechanical disintegration, there was accumulation of significant masses of carbonate detritus that was transported by repeated gravitational currents downslope and into the basin. examples of such events during the early jurassic have been found within the slope sediments in the vicinity of karlovac and banjaluka (gušić, 1969; mojičević et al., 1977; jelaska, 1987), but they also occur in upper jurassic and upper cretaceous deposits. it may be concluded that according to the results and data obtained, tectonic events in which the adcp was individualised, i.e. the events that marked the beginning of formation of its margins were not momentary, but rather the tectonic activity that lasted from the late sinemurian to the end of the toarcian. this interpretation correspond to the results from the study of the early jurassic extensional tectonic activity in the periadriatic region published by different authors (e.g. bernoulli, 1971; jelaska, 1973; zappaterra, 1990, 1994; bassoullet et al., 1993; gambini & tozzi, 1996; grandić et al., 1999). 3.3. stable period of the platform regime palaeogeographic relationships in the marginal part of the carbonate platform – on the carbonate slope and nearby basin – were relatively straightforward from the earliest middle jurassic to the late albian/early cenomanian. on the platform, a thick sequence of shallow marine carbonates of mostly biogenic origin was deposited. however, as already described, during the middle jurassic the very margin of the platform was mostly emerged (fig. 27). during this period the emerged area was similar to that in the toarcian, spreading continuously from the slovenian suha krajina area to southern bosnia in the kupres polje. in the platform shallows around land areas and between islands, predominantly oolitic carbonates were deposited. as already pointed out in southern slovenia according to dozet (2000a, b), such carbonate sedimentation lasted from the aalenian to the kimmeridgian, resulting in 450 to 500 m thick ooid limestones. the main characteristic of the late jurassic events was the fast growth of reef-building organisms along the platform margin. their large biologic potential produced significant masses of reef limestones and biodetritus, and they built the most significant and most characteristic palaeogeomorphological buildups during the whole history of the adcp – the coral–hydrozoan barrier-type reefs (fig. 28). in the study area between the rivers kupa, bosna and neretva such buildups were found in the broader surroundings of karlovac in 222 geologia croatica 55/2 223dragičević & velić: the northeastern margin of the adriatic carbonate platform croatia (bukovac et al., 1974, 1984). to the south, in the region of kordun and further se in nw bosnia all the way to bosanska krupa they were not preserved in the form of a continuous biolithite belt. locally, there are remains of patch-reefs within the “clypeina–campbelliella limestones”, e.g. west of cetingrad and near cazin (šparica, 1981). there are three main reasons for their non-existence or non-preservation. the first one was the fact that during the kimmeridgian and tithonian a “tongue” of the lemeš trough existed in the broader area of bihać, extending into the open and deep marine tethys. this means that it was a deeper water area (fig. 28) where reefs could not exist. an unknown part of the platform marginal area, covered by transgressive successions of younger deposits (of upper cretaceous, neogene and quaternary age) is the second reason and the third one was a consequence of the tertiary tectonics, since the platform margin is recently covered by overthrust permian and triassic deposits. the lemeš trough extended in a southerly direction into the platform interior, all the way to sinj (velić et al., 2002a, b). if any reefs did exist at all at the platform margin in the area of the lemeš trough “tongue”, they were destroyed by the synsedimentary activity of waves and currents, as well as by younger tectonics. additionally, a significant part of the older marginal platform facies and sequences was tectonically disrupted and reduced during the cretaceous, and during the late cretaceous covered by younger transgressive upper cretaceous–palaeogene carbonate–clastic sediments. southeastward in the study area, the upper jurassic barrier reefs appear on the platform margin near bosanska krupa and extend in a se direction through nw and central bosnia to the region s of sarajevo and then to northern herzegovina. continuation of the reef facies along the platform margin in a se direction can be traced through herzegovina and montenegro all the way to the cukali–budva trough in northern albania and southern montenegro. barrier reefs have also been found at the nw margin of the adcp in slovenia, in the area of novo mesto extending in a western direction to trnovski gozd and s of tolmin (e.g. buser, 1973, 1986; buser et al., 1967; turnšek et al., 1981; turnšek, 1997). due to the fact that reef-building organisms have lived within specific environments they are not reliable index fossils. to some extent, this has resulted in differences in the interpretation of the age of this marginal biolithite belt. in slovenia and croatia, where its stratigraphic position was mostly explored, the reef facies of the platform margin is covered with prograding oolithic–bioclastic grainstones and peritidal “clypeina–campbelliella limestones”. the stratigraphic position of the reef facies in the slovenian literature was denoted within the oxfordian and kimmeridgian (e.g. buser, 1973, 1986; buser et al., 1967; turnšek et al., 1981; turnšek, 1997). alternatively, nikler (1978) has determined upper malm, most likely tithonian reef facies in the slovenian trnovski gozd mt. the reef limestones in croatia are of kimmeridgian–tithonian age, not exclusively at the platform margin near karlovac (bukovac et al., 1974, 1984) but also in the inner parts of the platform, e.g. in velika kapela mt. (milan, 1969; velić, 1977; nikler, 1978). these limestones are the lateral time-equivalent of the “clypeina–campbeliella limestones” which were deposited in the back-reef platform shallows. according to the aforementioned references, the barrier reef limestones in bosnia and herzegovina and in northern montenegro were attributed to the late jurassic, and this cannot be revised without more detailed stratigraphic determination. the jurassic/cretaceous transition is marked by the emersion of the central parts of the platform (fig. 29; velić et al., 2002a). some emerged areas (islands) were determined along the ne platform margin between bihać and bosanska krupa, banjaluka and jajce, bugojno and prozor, and also sw of sarajevo in bosnia and se of šavnik in montenegro. facies characteristics of lower cretaceous carbonates of the marginal area do not differ from contemporaneous deposits in other parts of the platform. they have no specific characteristics which would indicate platform margin environments. contrary to the upper jurassic carbonates close to or at the platform margin, the lower cretaceous carbonate sequences are significantly more uniform in terms of facies. they were mostly deposited in restricted environments, from lagoonal to shallow subtidal areas (orbitolinid and salpingoporella limestones), but occasionally also to supratidal ones, with emersions. no significant occurrences of marginal platform facies, e.g. oolithic or biolithite limestones were determined, especially of the barrier type (fig. 30). even if they existed, they were most probably penecontemporaneously destroyed by waves, and the material was redeposited. this is proven by the very frequent rudist and other bioclasts (including other bivalves, gastropods, corals, hydrozoans etc.), that are found in limestones deposited in the restricted back-reef shallows. fragments, boulders and blocks formed during the late cretaceous destruction of the lower cretaceous shallow marine carbonates on the platform margin have been found in the clastic–carbonate debrites in the vicinity of banjaluka and jajce (dragičević, 1987). there is only one location, n of the kupres polje (fig. 30), where the upper barremian–lower aptian reef limestones were determined. they probably belong to the marginal platform reef with remains of corals, bryozoans, hydrozoans, corallinaceans, large gastropods and rudists (dragičević & velić, 1994). similar relationships were determined for the early cretaceous in other marginal parts – extending in both se and nw directions. it is interesting to mention that in western slovenia, s of tolmin (banjška planota and trnovski gozd mts.) the coral–hydrozoan reef lime222 geologia croatica 55/2 223dragičević & velić: the northeastern margin of the adriatic carbonate platform stones of aptian and albian age were developed (fig. 30), containing numerous remains of corals, hydrozoans, chaetids, gastropods (nerineids) etc. (buser, 1986; turnšek, 1997). the end of the early and beginning of the late cretaceous was, in the study area of the platform margin, marked by significant tectonics and emersion. during this period bauxite deposits were deposited in the vicinity of jajce on the palaeorelief of the extensively eroded and karstified albian limestones (dragičević, 1987). similar conditions were also determined in the surroundings of bihać in nw bosnia and on grmeč mt. (polšak et al., 1978; šinkovec & babić, 1973). this was the end of the long-lasting period of the relatively stable shallow marine platform regime, which lasted from the younger early jurassic to the end of the early cretaceous/early cenomanian. 3.4. the beginning of platform disintegration in the cenomanian–santonian the late cretaceous was the time of the most significant events and biggest changes along the ne margin of the adcp and the beginning of platform disintegration. these events and changes were mostly and most complexelly reflected exactly in the area investigated from žumberak in central croatia to the valley of the bosna river and kupres polje in bosnia and herzegovina. as already mentioned, the older upper cretaceous deposits were sporadically deposited and they can be found in rare localities along the platform margin (e.g. dubravčani, cetingrad, ravanac, guča gora, čardak livade, strojice – figs. 4, 7, 18, 20, 22, 23). most of the platform marginal area was emergent during this period (dragičević & velić, 1994). the late albian or early cenomanian was a period of significant tectonic movements when the process of disintegration and changes in physiography of the ne platform margin was initiated. the sequence of events started with differential faulting and folding parallel to the previous platform margin, followed by uplift, emersion and karstification. during the emersion phase, which at the platform margin lasted during the cenomanian, turonian and coniacian (probably even during the early santonian), bauxite deposits were formed on land in areas of favourable relief. with continuing tectonics, the previously morphologically flattened area of the platform margin was fragmented and reshaped into several chains of longitudinal, more or less parallel morphological uplifts – the uplifted parts separated by elongated depressions. these events played a decisive role in the palaeogeography of the platform margin in the final phase of its disintegration during the late cretaceous. 3.5. santonian transgression a late santonian transgression gradually flooded the aforementioned emergent areas, so that in some places there were pronounced changes in palaeogeography and architecture of the marginal area. the most markedly developed changes were documented in the area se of banjaluka and in some places in the vicinity of karlovac. due to the gradual transgression, the sea flooded depressions in the relief where clastic–carbonate sedimentation of slope-to-basin facies developed. recently their remains are found in several, isolated narrow elongated troughs in the area between livno, kupres, jajce, banjaluka, bihać, slunj and ozalj (fig. 31). uplifted parts of the terrain became islands with a continuation of the erosion and karstification processes. several “island chains” existed that were parallel to the platform margin. the largest islands, and also those with the longest terrestrial regime were located exactly at fig. 32 seismic profile of the adriatic carbonate platform margin s of karlovac (fig. 1, locality 24). legend: a) mesozoic platform carbonates; b) upper cretaceous debrites and turbidites; c) tertiary and quaternary carbonate-clastic deposits 70° 224 geologia croatica 55/2 225dragičević & velić: the northeastern margin of the adriatic carbonate platform the platform margin (“outer island chain”), while both the dimensions of the islands and their duration diminished towards the central parts of the platform (“inner island chains”). due to mechanical weathering in the coastal areas, large masses of lithoclasts were formed (predominantly of lower cretaceous limestones) that were transported to the basin by gravitational currents. in the islands interior there was mostly chemical weathering and modelling of the karst relief so that the source material (most likely volcanic ash and volcanic dust) for the bauxite occurrences and deposits was accumulated in the relief depressions – dolinas. these occurrences are of broad regional extent, and were found in many places along the platform margin: in sabotin (gorica) in slovenia, in kordun and karlovac areas in croatia, in the surroundings of jajce, bosanska krupa and grmeč mt. in western bosnia, and near klina (kosovo – serbia and montenegro). with the advancement of the transgression, depositional environments changed: islands became small isolated carbonate platforms and depressions were transformed into troughs with basinal sedimentation. on the small platforms there was explosive renovation and fast growth of rudist communities. biolithite bodies and bioherms up to a km in length are frequently encountered, especially at the platforms’ margins. basinal sedimentation in troughs under constant tectonic influence produced unstable environmental conditions, especially marked by the redeposition of large masses of both lithoand bioclasts derived from destruction of the rudist biolithites at the margins of small platforms. blocks, boulders and lithoclasts within debrites originate from the platform carbonates of various ages. those of early and late cretaceous age prevail, but there are also some of triassic and late jurassic age. such relationships lasted from the late santonian, through the campanian and most of the maastrichtian. 3.6. the end of the platform regime: maastrichtian and palaeocene flooding of the marginal area at the maastrichtian/palaeocene transition, fragmented carbonate complexes – small platforms of the adcp margin area – were finally drowned. deeper water to basinal environments were formed, resulting in the cretaceous/palaeocene continuity of basinal deposition. all of this indicates migration of the platform margin and deep marine environments in the direction of the south and south-west, and also the gradual diminishing of platform “stability” and at the same time intensified tectonic mobility. tectonic activity at the ne margin of the adcp was the most important factor during its entire evolution. it directly or indirectly controlled the intensity of erosion, inclination of slopes, bathymetric relationships, reef growth and formation of other environments. tectonics also initiated the sedimentary gravitational flows that deposited large masses of turbidites and debrites. in the basinal areas, significant masses of autochthonous sediments (“scaglia” type limestones and chert) accumulated. the almost constant tectonic activity in the studied part of the platform margin can be interpreted from the given descriptions of palaeogeographic changes and registered hiatuses, including the unconformable and transgressive position of the santonian–maastrichtian carbonate–clastic sediments over various older stratigraphic units. this allows the conclusion that presantonian tectonics resulted in the formation of fault contacts between various units of the lower triassic to upper cretaceous time span. in this way carbonate–clastic sediments of the santonian to maastrichtian/palaeocene age in the žumberak area overlie various stratigraphic units of triassic, basinal jurassic and upper jurassic barrier-reef carbonates (pleničar et al., 1976; bukovac et al., 1984). in the kordun area they overlie the middle and upper triassic, upper jurassic, barremian to turonian platform carbonates (korolija et al., 1981; šparica, 1981), and in the surroundings of bihać upper jurassic “clypeina limestones” and barremian to albian salpingoporella and orbitolinid carbonates (polšak et al., 1977). between the una and vrbas rivers they cover the triassic (mostly upper triassic) carbonates and upper jurassic coral–hydrozoan barrier-reefs (mojičević et al., 1978; marinković & ahac, 1980; jelaska, 1987). in the vicinity of jajce, they transgressively cover platform carbonates of aptian, albian and cenomanian age, and also cenomanian limestones in vlašić mt. (dragičević, 1987). they also overlie upper jurassic platform barrier-reef to slope deposits and various platform carbonate sequences of the early cretaceous in the kupres polje and tomislavgrad area in sw bosnia (papeš, 1972, 1985; vujnović, 1980; dragičević, 1987). tectogenesis of the ne adcp margin and formation of the recent tectonic relationships evolved in the framework of regional changes and events of the wider mediterranean region. complex tectonic relationships were formed in the period from the upper cretaceous to the recent. their recent manifestation is the existence of large masses of mesozoic platform carbonate rocks, which originally represented integral parts of the adriatic carbonate platform, overthrust toward the ne and e and recently located ne of the main body of clastic deposits – flysch that was deposited on the slope and in the basin along the ne platform margin. this is especially obvious in some areas in bosnia, such as vlašić, čemernica and the osmača mts., and probably also the igman and bjelašnica mts. the present setting of the shallow marine mesozoic carbonate complex in žumberak and the samobor mts. in croatia is almost identical to the one described above – it is located ne of the main zone of upper cretaceous flysch, which means that their allochthonous position can not be excluded. 224 geologia croatica 55/2 225dragičević & velić: the northeastern margin of the adriatic carbonate platform 4. palaeogeographic migration of the northeastern margin of the adriatic carbonate platform the recent geological relationships along the entire margin of the adcp are very complex and frequently unclear. nevertheless, they enable at least a partial reconstruction of its variable (palaeo)geographic position during the platform’s existence (fig. 33). by analysis of the spatial distribution and interrelationships between the relevant facies of the platform margin, slope and basin, margin migrations probably occurred during the jurassic and cretaceous. although recently identifiable only in some areas, changes of the platform margin position were more frequent due to the tectonic–eustatic factors which consequently determined its extent and size. the best explored and determined (both in a stratigraphic and palaeogeographic sense) is the example of the migration of the platform margin in the jurassic of žumberak and samobor mts. in croatia. its different positions in the early and late jurassic were described by babić (1976). compared to the early jurassic the platform margin during the late jurassic was located approximately 25 km southwestward (babić, 1976; bukovac et al., 1984). this means that, by the end of jurassic and in the beginning of cretaceous, the platform was “narrowed” by the size of this displacement. the development and cause of these changes were explained by šikić & basch (1975) and šikić et al. (1979), as being due to regional tectonic activity during the middle and beginning of the late lias. the ne parts of the triassic–lias carbonate platform were fragmented by faults of nw–se strike and submerged, and platform sedimentation was gradually replaced by basinal types. these jurassic changes of the platform margin were consequences of the determined early jurassic extensional tectonics in the periadriatic area which caused significant palaeogeographical events – isolation of the adriatic carbonate platform and its separation from the apulian and apenninic platforms (bernoulli, 1971; jelaska, 1973; zapaterra, 1990, 1994; bassoullet et al., 1993; grandić et al., 1999). reflection of the extensional tectonics on the adriatic platform resulted in regional faulting and sea-level fall and emersion of the ne marginal area. from trnovski gozd mt. in slovenia at the western part of the platform margin all the way to northern montenegro and nw albania, the emerged areas existed as smaller or larger islands between the inner platform shallows towards the sw and slope to basinal environments in the ne (figs. 26, 27). the biggest land area, more likely an elongated island than a linear archipelago, extended from the suha krajina region in se slovenia to the central part of the neretva river-course in bosnia and herzegovina. in the shallows of the platform margin area that had not been emerged, ooid carbonates were mostly deposited. there are no reliable data on the position of the platform margin during the middle jurasic. the platform was reduced in respect to the size of the shallow water area in early lias time in slovenia and the žumberak area, but its margin and slope lay ne of the island(s) belt and extended from žumberak to central bosnia, supposedly being shifted in a ne direction i.e. towards the basinal area. according to recent relationships, the middle jurassic position of the platform margin in herzegovina is supposed somewhat northeastward and in montenegro southwestward of the location of the early jurassic one. in slovenia it was slightly shifted toward the inner platform area. the barrier coral–hydrozoan reefs marked the platform margin during the late jurassic. these biolithite complexes were environmentally connected with the very margin of the platform and the platform area slowly expanded with their progradation over the slope facies towards the basinal area. the recent position of the platform margin in the jajce–zenica area where, compared with its position during the early and middle jurassic, the platform is approximately 70 km shifted eastward, is probably a consequence of the tertiary overthrust tectonics. outwith the study area, the late jurassic extension of the platform margin by progradation of the reef facies was not very important, except at some localities in montenegro. according to the recent distribution of platform facies pertaining to the early cretaceous and the early late cretaceous (fig. 33) the platform margin retreated in a sw direction with respect to its jurassic position. however, as in the upper jurassic, precise data can not be obtained due to masking of the marginal area either by overthrust older or transgressive younger deposits. the shift of the margin towards the sw during the latest cretaceous (from the santonian to the end of the maastrichtian) in a constant transgressive trend marked the final phase of platform disintegration by its continuous narrowing, i.e. extension of the slope and basinal facies and reduction of the platform facies area. as described in the previous section, this was mostly reflected in the area from žumberak to central bosnia from the santonian to the end of the cretaceous. together with the previously quoted authors, some interesting data regarding the late jurassic–maastrichtian shifts of the platform margin were provided by jelaska (1987). late cretaceous tectonics disrupted the transgressive tendencies and the process of narrowing of the shallow marine depositional area by the uplift and emersion of the largest part of the platform. this degraded an integral and long lasting shallow marine depositional area and marked the end of the existence of the adriatic carbonate platform as a unique shallow marine depositional system. the ne platform margin area composed of jurassic and cretaceous carbonate platform sequences was, during the maastrichtian progressive transgres226 geologia croatica 55/2 227dragičević & velić: the northeastern margin of the adriatic carbonate platform sion, mostly “flooded” and covered with maastrichtian–palaeogene basinal, mostly flysch deposits. in spite of these changes, the ne margin of the adcp, has kept its relatively stable position and orientation during the “life” of the platform and its geodynamic development that lasted from the early jurassic to the end of cretaceous. smaller differences and migrations of the margin were caused by its geodynamic evolution, reflecting the influences of eustatic and tectonic events, most frequently on a local scale. these events caused either the regressive or transgressive movements which resulted in progradational or retrogradational processes and deposition of their corresponding sequences on the very margin of the platform. the platform margin migrations on fig. 33 show that there is clear disharmony in the position of the margin through time from the early jurassic to the end of the cretaceous in the area from žumberak to central bosnia (bugojno–zenica area). in contrast, in slovenia, herzegovina and montenegro, the margin position was more or less constant. disharmony could be interpreted by different palaeogeographic positions in various jurassic and cretaceous ages, and by the consequences of post-platform tectonics. in the kordun and nw bosnia the platform marginal parts were overthrust by the permian and triassic deposits. southeastward, in the area between ključ and sarajevo, uplift of the central bosnian palaeozoic complex of the platform basement caused faulting of the platform margin carbonate successions and their partial overthrusting over the slope and basinal flysch deposits of upper cretaceous and palaeogene age. as a result of this tectonic activity the osmača, čemernica and vlašić mts., between banjaluka and zenica, were torn away from the adcp margin and overthrust on the aforementioned younger deposits (dragičević, 1987). it seems that similar events took place in žumberak and the samobor mts. where allochthonous triassic and earliest jurassic shallow marine carbonates were overthrust over upper cretaceous–palaeocene basinal deposits, mostly flysch (šikić et al., 1978; pleničar et al., 1976). 5. conclusion due to extensional tectonics in the periadriatic region that occurred from the end of the sinemurian through the pliensbachian and toarcian, the previously unified shallow marine area on the adria microplate was split into several smaller entities. in this way, in the southern part of tethys, several isolated carbonate platforms were formed, of which the adriatic carbonate platform (adcp) was one. as a shallow marine carbonate depofig. 33 sketch of the ne adriatic carbonate platform margin migrations from the toarcian to the maastrichtian. n 226 geologia croatica 55/2 227dragičević & velić: the northeastern margin of the adriatic carbonate platform sitional system it lasted until the end of the cretaceous. when this platform was individualised, its margins and slopes were formed, which are recently mostly unavailable for investigation, partly because of the tectonic complexity and partly due to coverage by younger deposits. the sw margin and slope lie beneath the adriatic sea completely covered by tertiary and quaternary sediments, and only data regarding their shape and position have been acquired by geophysical measurements and results from deep oil and gas exploration wells. on the opposite side of the platform, in spite of the significant tectonic disruption and partial coverage with cretaceous–palaeogene flysch and neogene–quaternary deposits, the ne marginal area with the characteristic facies of the platform margin and slope is locally exposed and can be recognized. the initial tectonic–palaeogeographic changes connected with the processes of individualisation of the adcp in the early jurassic were reflected at its ne margin. part of the previous shallow marine area was flooded and the border between the basinal and platform sedimentation during the middle and late jurassic was shifted in a sw direction. this is most clearly marked in the žumberak and karlovac area, in the middle lias to valanginian depositional sequences, in spite of the fact that most of the platform margin along the strike was emerged during the middle lias–kimmeridgian period. contemporaneously, mostly ooid–bioclastic carbonates were deposited in the marginal platform shallows, and the platform margin mostly retains its (palaeo)geographic position. in the late jurassic (kimmeridgian and tithonian) the platform margin was marked by the coral–hydrozoan barrier reefs. the platform margin locally migrated towards the north-east by reef progradation in the basinal direction, over the slope facies. the smallest amount of data is available on the events at the platform margin during the early cretaceous and the cenomanian. there are sporadic occurrences of the coral–hydrozoan–rudist biolithite buildups such as in western slovenia (banjška planota) and in central bosnia (between jajce and kupres polje). facies characteristics of the recently discovered carbonate sediments of the platform margin indicate more restricted environments. it is supposed that during the early cretaceous, the platform margin was located somewhat further sw of its late jurassic position. the late cretaceous period was the most dynamic period in the history of the platform. the fact that rudist limestones, which are very important for the inner platform area, were found only in a few localities along the platform margin, indicate that the platform margin was emerged from the late albian to early santonian. this is a consequence of the late cretaceous tectonics that started in the upper albian and were continuously active until it finally destroyed the platform at the end of the cretaceous. in the vicinity of jajce (liskovica, bešpelj etc.), the karstified palaeorelief of albian limestones was partially infilled by bauxite deposits. there are some localities with continuity of depositon of rudist limestones until the emersion in the middle and late cenomanian. on the karstified palaeorelief of these limestones there are also bauxite occurrences, e.g. in the vicinity of karlovac in croatia (dubravčani), and in bosnia – in the grmeč mt., n of glamoč (čardak livade), e of jajce (ravanac) and in vlašić mt. (guča gora locality). deposition of platform rudist limestones was renewed during the santonian transgression. at the very margin of the platform towards the open tethys, there were numerous rudist colonies building biolithite bodies. apart from rudists, there are the remains of reef-building organisms – corals, hydrozoans, stromatoporoids, bryozoans, sponges, algae, echinoids, gastropods and bivalves. due to the penecontemporaneous mechanical destruction of these buildups, large masses of bioclasts and lithoclasts were formed and together with the mud deposited on the fore-reef and upper slope, were transported down the slope by turbidity currents and debris flows. these coarse-grained clastic sediments represent the proximal facies of the more fine-grained campanian–maastrichtian carbonate–clastic sediments (flysch) deposited during the peak of the transgression. the area of carbonate–clastic sedimentation gradually retreated from the former marginal area in a sw direction, covering the platform carbonates. this relatively fast flooding also represented the end of the platform margin and final disintegration of the platform. in this way the end of the cretaceous marked the end of the existence of the dynamic shallow marine carbonate depositional system – the adriatic carbonate platform which, in this final act, changed from being extant into extinct. acknowledgement the authors are sincerely grateful to the reviewers, professor vladimir jelaska (faculty of sciences, university of zagreb), dr. bojan ogorelec (geological survey of slovenia), dr. igor vlahović (institute of geology zagreb) and dr. julie robson (open university milton keynes) for their comments and useful suggestions, as well as to mr. ivan kratković and mr. željko markulin (ina-naftaplin zagreb) for seismic profile presented in this paper. 6. references antonijević, r., pavić, a., karović, j., dimitrijević, m., radoičić, r., pejović, d., pantić, s. & roksandić, m. (1973): osnovna geološka karta sfrj 1:100.000. tumač za list kotor l34–50 (basic geological map of sfry 1:100,000. geology of the kotor sheet).– zavod za geološka i geofizička istraživanja beograd (1964), savezni geološki zavod beograd, 64 p. 228 geologia croatica 55/2 229dragičević & velić: the northeastern margin of the adriatic carbonate platform babić, lj. (1973): bazenski sedimenti gornjeg titona, berijasa i valendisa zapadno od bregane (upper tithonian to valanginian basinal sediments west of bregana).– geol. vjesnik, 26, 11–27. babić, lj. (1974): razdoblje otriv–cenoman u žumberku: stratigrafija, postanak sedimenata i razvoj prostora (hauterivian to cenomanian time in the region of žumberak, northwestern croatia).– geol. vjesnik, 27, 11–33. babić, lj. (1976): pomak granice između unutrašnje i vanjske dinarske regije, primjer šireg područja žumberka (migration of the boundary between “inner” and “outer” dinaric zones).– zbornik radova 8 jugosl. geol. kongresa bled (1974), ljubljana (proceedings of the 8th yugosl. geol. congress), 2, 45–51. babić, lj. (1980): pojave vapnenanca s kalpionelidama na rudnici (posavske bore, istočna slovenija) (limestone with calpionellids on mt. rudnica, eastern slovenia) – geol. vjesnik, 31, 13–20. babić, lj. & zupanič, j. (1976): sedimenti i paleogeografija zone globotruncana calcarata (gornja kreda) u baniji i kordunu (središnja hrvatska) (sediments and paleogeography of the globotruncana calcarata (upper cretaceous) in banija and kordun, central croatia).– geol. vjesnik, 29, 49–73. bassoullet, j.p., elmi, s., poisson, a., cecca, f., bellion, y., guiraud, r. & baudin, f. (1993): middle toarcian (184 to 182 ma).– in: dercourt, j., ricou, l.e. & vrielynck, b. (eds.): atlas tethys palaeoenvinronmental maps. explanatory notes. gauthiervillars, paris, 63–80. bernoulli, d. (1971): redeposited pelagic sediments in the jurassic of the central mediterranean area.– annales instituti geologici publici hungarici, 54/2, 71–90. blanchet, r. (1975): de l’adriatique au bassin pannonique – essai d’un modèle de chaîne alpine.– mém. soc. géol. france, 53 (120), 1–172. bucković, d., jelaska, v. & cvetko, b. (2001): facies variability in lower liassic carbonate successions of the western dinarides (croatia).– facies, 44, 151–162. bukovac, j. & sokač, b. (1989): upper triassic–lower liassic limestones on the northern slopes of mt. gorjanci and south of kostanjevica (southeast slovenia) and their significance for the geotectonics of the larger area.– geol. vjesnik, 42, 7–13. bukovac, j., velić, i. & sokač, b. (1974): stratigrafski, tektonski i paleogeografski odnosi u području dugarese, barilovića i skradske gore (stratigraphy, tectonics and paleogeography of the region between dugaresa, barilović and skradska gora).– geol. vjesnik, 27, 59–77. bukovac, j., šušnjar, m., poljak, m. & čakalo, m. (1984): osnovna geološka karta sfrj 1:100.000. list črnomelj l33–91 (basic geological map of sfry 1: 100,000. the črnomelj sheet).– geološki zavod zagreb, geološki zavod ljubljana (1972–1983), savezni geološki zavod beograd. buser, s. (1968): osnovna geološka karta sfrj 1:100.000. list gorica l33–76 (basic geological map of sfry 1: 100,000. the gorica sheet).– geološki zavod ljubljana (1958–1963), savezni geološki zavod beograd. buser, s. (1969): osnovna geološka karta sfrj 1:100.000. list ribnica l33–78 (basic geological map of sfry 1: 100,000. the ribnica sheet).– geološki zavod ljubljana (1961–1965), savezni geološki zavod beograd. buser, s. (1973): osnovna geološka karta sfrj 1:100.000. tolmač lista gorica l33–76 (basic geological map of sfry 1:100,000. geology of the gorica sheet).– geološki zavod ljubljana (1964), savezni geološki zavod beograd, 50 p. buser, s. (1986): osnovna geološka karta sfrj 1:100.000. tolmač listov tolmin in videm l33–64, l33–63 (basic geological map of sfry 1:100,000. geology of the tolmin and videm sheet).– geološki zavod ljubljana (1985), savezni geološki zavod beograd, 1–103. buser, s. (1987): osnovna geološka karta sfrj 1:100.000. list tolmin in videm l33–64 (basic geological map of sfry 1:100,000. the tolmin and videm sheet).– geološki zavod ljubljana (1969–1984), savezni geološki zavod beograd. buser, s. (1989): development of the dinaric and the julian carbonate platforms and of the intermediate slovenian basin (nw yugoslavia).– mem. soc. geol. ital., 40, 313–320. buser, s., grad, k. & pleničar, m. (1967): osnovna geološka karta sfrj 1:100.000. list postojna l33–77 (basic geological map of sfry 1:100,000. the postojna sheet).– geološki zavod ljubljana (1963), savezni geološki zavod beograd. buser, s., pavšič, j. & aničić, b. (1982): globokomorske kredne plasti v vzhodni sloveniji (deep sea cretaceous beds of eastern slovenia).– zbornik radova 10. jub. kongr. geol. juslavije – budva, 1, 11–23. dercourt, j., ricou, l.e. & vrielynck, b. (eds.) (1993): atlas tethys palaeoenvinronmental maps.– gauthier-villars, paris, 307 p. dozet, s. (1994): stratigraphy of the suha krajina area (slovenia) and stratigraphic gap middle liassic–lower malm.– rudarsko–metalurški zbornik, 41, 231–238, ljubljana. dozet, s. (2000a): hočevje oolitic group, central slovenia.– acta carsologica, 29/1,185–189, postojna. dozet, s. (2000b): stratigraphy of the verd oolitic limestone complex.– rudarsko–metalurški zbornik, 47, 245–254, ljubljana. dozet, s. & šribar, lj. (1998a): biostratigraphy of shallow marine jurassic beds in southeastern slovenia.– geologija, 40, 187–221. dozet, s. & šribar, lj. (1998b): lower cretaceous shallow-marine sedimentation and biota on dinaric carbonate platform between logatec, krka and kolpa (southeastern slovenia).– geologija, 40, 153–185, ljubljana. dragičević, i. (1987): paleogeografska evolucija rubnog dijela mezozojske karbonatne platforme dinarida između vrbasa i bosne (palaeogeographical evolution of the marginal zone of the mesozoic carbonate platform of dinarides in the area between vrbas and bosna rivers – in croatian with english summary).– unpubl. phd thesis, university of zagreb, 90 p. 228 geologia croatica 55/2 229dragičević & velić: the northeastern margin of the adriatic carbonate platform dragičević, i. & velić, i. (1994): stratigraphical position and significance of reef facies at the northern margin of the dinaric carbonate platform during the late jurassic and cretaceous in croatia and bosnia.– géologie méditerranéenne, 21/3–4, 59–63 đerković, b., maksimčev, s., vilovski, s., kujundžić, s., sunarić, o., hohrajn, j., kovačević, r., kačar, b., veljović, r., jojić, d., marić, lj., ložajić, m., pamić, j., kapeler, i., đorđević, d. & jurić, m. (1976): osnovna geološka karta sfrj 1:100.000. list prijedor l33–118 (basic geological map of sfry 1:100,000. the prijedor sheet).– institut za geološka istraživanja sarajevo (1961–1967), savezni geološki zavod beograd. đokić, v., živaljević, m. & perović, z. (1973): osnovna geološka karta sfrj 1:100.000. list gusinje k34–52 (basic geological map of sfry 1:100,000. the gusinje sheet).– zavod za geološka istraživanja titograd (1958–1968), savezni geološki zavod beograd. gambini, r. & tozzi, m. (1996): tertiary geodynamic evolution of the southern adria microplate.– terra nova, 8, 593–602. grandić, s. & vuksanović, b. (1973): kordun kao novo boksitonosno područje na teritoriji sr hrvatske (kordun als neues bauxit-gebiet auf dem terrain der sr kroatien).– 2. jugosl. simp. istraž. ekspl. boksita, tuzla, 5. grandić, s., boromisa-balaš, e., šušterčić, m. & kolbah, s. (1999): hydrocarbon possibilities in the eastern adriatic slope zone of croatian offshore area.– nafta, 50/2, 51–73, zagreb. gušić, i. (1969): biostratigrafske i mikropaleontološke karakteristike nekih jurskih profila iz područja centralne hrvatske (biostratigraphic and micropaleontologic characteristics of some jurassic cross-sections in central croatia).– geol. vjesnik, 22, 89–97. gušić, i. & babić, lj. (1970): neke biostratigrafske i litogenetske osobine jure žumberka (some biostratigraphic and lithogenetic characteristic of the jurassic in žumberak, northwest croatia).– geol. vjesnik, 23, 39–54. gušić, i. & jelaska, v. (1990): stratigrafija gornjokrednih naslaga otoka brača u okviru geodinamske evolucije jadranske karbonatne platforme (upper cretaceous stratigraphy of the island of brač within the geodynamic evolution of the adriatic carbonate platform).– jazu and inst. geol. istraživanja, zagreb, 160 p. gušić, i. & jelaska, v. (1993): upper cenomanian– lower turonian sea-level rise and consequences on the adriatic–dinaric carbonate platform.– geol. rundschau, 82/4, 676–686. jelaska, v. (1973): paleogeografska i naftnogeološka razmatranja zapadnog dijela karbonatnog šelfa dinarida (paleogeographic and oil-geologic considerations of the west part of the dinaride carbonate shelf).– geol. vjesnik, 25, 57–64. jelaska, v. (1987): paleoambijentalna dinamika sjeveroistočnog rubnog prostora vanjskih dinarida u juri i kredi (jurassic and cretaceous paleoenvironmental dynamic of the northeastern margin of the outer dinarides).– geol. vjesnik, 40, 195–216. jelaska, v., amšel, v., kapović, b. & vuksanović, b. (1969): sedimentološke karakteristike klastične gornje krede zapadnog dijela bosanske krajine (sedimentologic characteristics of the clastic upper cretaceous of the western part of bosanska krajina).– nafta, 10, 487–495, zagreb. jelaska, v., gušić, i., jurkovšek, b., ogorelec, b., ćosović, v., šribar, l. & toman, m. (1994): the upper cretaceous geodynamic evolution of the adriatic–dinaric carbonate platform(s).– géol. méditerranéenne, 21/3–4, 89–91. jovanović, r., mojičević, m., tokić, s. & rokić, lj. (1977): osnovna geološka karta sfrj 1:100.000. list sarajevo k34–1 (basic geological map of sfry 1: 100,000. the sarajevo sheet).– zavod za inženjersku geologiju i hidrogeologiju građevinskog fakulteta u sarajevu (1962–1967), savezni geološki zavod beograd. jurić, m. (1977): osnovna geološka karta sfrj 1:100.000. tumač za list prijedor l33–118 (basic geological map of sfry 1:100,000. geology of the prijedor sheet).– geoinženjering sarajevo (1975), savezni geološki zavod beograd, 55 p. jurkovšek, b., šribar, l., ogorelec, b. & kolarjurkovšek, t. (1988/89): pelagične jurske in kredne plasti v vzhodnem delu julijskih alp (pelagic jurassic and cretaceous beds in the western part of the julian alps).– geologija, 31–32, 285–328. jurkovšek, b., toman, m., ogorelec, b., šribar, l., drobne, k., poljak, m. & šribar, lj. (1996): formacijska geološka karta južnega dela tržaško– komenske planote. kredne in paleogenske karbonatne kamnine, 1:50.000 (geological map of the southern part of the trieste–komen plateau. cretaceous and paleogene carbonate rocks).– inst. geol., geoteh., geofiz. ljubljana, 143 p. kalezić, m. & mirković, m. (1970): osnovna geološka karta sfrj 1:100.000. list šavnik k34–39 (basic geological map of sfry 1:100,000, the šavnik sheet).– zavod za geološka istraživanja titograd (1962–1966), savezni geološki zavod beograd. kalezić, m., mirković, m. & škuletić, d. (1973): osnovna geološka karta sfrj 1:100.000. tumač za list šavnik k34–39 (basic geological map of sfry 1: 100,000. geology of the šavnik sheet).– zavod za geološka istraživanja titograd (1966), savezni geološki zavod beograd, 65 p. korbar, t., fuček, l., husinec, a., vlahović, i., oštrić, n., matičec, d. & jelaska, v. (2001): cenomanian carbonate facies and rudists along shallow intraplatform basin margin – the island of cres (adriatic sea, croatia).– facies, 45, 39–58. korolija, b., živaljević, t. & šimunić, a. (1980): osnovna geološka karta sfrj 1:100.000. list slunj l33–104 (basic geological map of sfry 1:100,000. the slunj sheet).– institut za geološka istraživanja zagreb, geološki zavod sarajevo (1968–1972), savezni geološki zavod beograd. korolija, b., živaljević, t. & šimunić, a. (1981): osnovna geološka karta sfrj 1:100.000. tumač za list slunj l33–104 (basic geological map of sfry 1:100,000. geology of the slunj sheet).– institut za geološka istraži230 geologia croatica 55/2 231dragičević & velić: the northeastern margin of the adriatic carbonate platform vanja zagreb (1972) and geološki zavod sarajevo (1968), savezni geološki zavod beograd, 47 p. kuščer, d., grad, k., nosan, a. & ogorelec, b. (1974): geološke raziskave soške doline med bovcem in kobaridom (geology of the soča valley between bovec and kobarid).– geologija, 17, 425–476, ljubljana. marinković, r. & ahac, a. (1980): osnovna geološka karta sfrj 1:100.000. list jajce l33–131 (basic geological map of sfry 1:100,000, the jajce sheet).– geoinženjering sarajevo (1975), savezni geološki zavod beograd. marjanac, lj. & marjanac, t. (1987): continental slope and its sediments during cretaceous in krško hribovje (se slovenia, yugoslavia).– intern. symp. on the evolut. of karstic carbonate platform: relation with other periadriatic carb. platforms. univ. degli studi di trieste, abstracts, 43. milan, a. (1969): facijelni odnosi i hidrozojska fauna malma primorskog dijela sjevernog velebita i velike kapele (faziesverhältnisse und hydrozoenfauna des malms im küstenland des nördlichen velebit und velika kapela).– geol. vjesnik, 22, 135–217. mirković, m. (1980): osnovna geološka karta sfrj 1: 100.000. tumač za list gacko k34–26 (basic geological map of sfry 1:100,000. geology of the gacko sheet).– zavod za geološka istraživanja titograd (1974), savezni geološki zavod beograd, 67 p. mirković, m. & mirković, b. (1987): novi podaci o rasprostranjenju jurskih sedimenata u području sinjavine, durmitora i ljubišnje (new data about distribution of jurassic sediments in the area of sinjavina, durmitor and ljubišnja).– geološki glasnik, 12, 61–87, titograd. mirković, m. & vujisić, p. (1989): osnovna geološka karta sfrj 1:100.000. list žabljak k34–27 (basic geological map of sfry 1:100,000. the žabljak sheet).– zavod za geološka istraživanja titograd (1980–1986), savezni geološki zavod beograd. mirković, m., kalezić, m. & pajović, m. (1977): osnovna geološka karta sfrj 1:100.000. list bar k34– 63 (basic geological map of sfry 1:100,000. the bar sheet).– zavod za geološka istraživanja titograd (1968), savezni geološki zavod beograd. mirković, m., kalezić, m., pajović, m., živaljević, m. & škuletić, d. (1978): osnovna geološka karta sfrj 1:100.000. tumač za list bar k34–63 (basic geological map of sfry 1:100,000. geology of the bar sheet).– zavod za geološka istraživanja titograd (1968), savezni geološki zavod beograd, 67 p. mirković, m., pajović, m. & kalezić, m. (1979): osnovna geološka karta sfrj 1:100.000. list gacko k34–26 (basic geological map of sfry 1:100,000. the gacko sheet).– zavod za geološka istraživanja titograd (1967–1974), savezni geološki zavod beograd. mojičević, m. & laušević, m. (1969): osnovna geološka karta sfrj 1:100.000. list nevesinje k34–25 (basic geological map of sfry 1:100,000. the nevesinje sheet).– geološki zavod sarajevo (1958–1964), savezni geološki zavod beograd. mojičević, m. & laušević, m. (1971): osnovna geološka karta sfrj 1:100.000. list mostar k33–24 (basic geological map of sfry 1:100,000. the mostar sheet).– geološki zavod sarajevo (1958–1969), savezni geološki zavod beograd. mojičević, m. & laušević, m. (1973): osnovna geološka karta sfrj 1:100.000. tumač za list nevesinje k34–25 (basic geological map of sfry 1:100,000. geology of the nevesinje sheet).– institut za geološka istraživanja sarajevo (1965), savezni geološki zavod beograd, 53 p. mojičević, m. & tomić, b. (1982a): osnovna geološka karta sfrj 1:100.000. list kalinovik k34–13 (basic geological map of sfry 1:100,000. the kalinovik sheet).– geoinženjering sarajevo (1969–1977), savezni geološki zavod beograd. mojičević & tomić (1982b): osnovna geološka karta sfrj 1:100.000. tumač za list kalinovik k34–13 (basic geological map of sfry 1:100,000. geology of the kalinovik sheet).– geoinženjering sarajevo (1981), savezni geološki zavod beograd, 60 p. mojičević, m., vilovski, s. & tomić, b. (1977): osnovna geološka karta sfrj 1:100.000. list banjaluka l33–119 (basic geological map of sfry 1:100,000. the banjaluka sheet).– institut za geološka istraživanja sarajevo (1964–1969), savezni geološki zavod beograd. mojičević, m., maksimčev, s. & vrhovčić, j. (1978): osnovna geološka karta sfrj 1:100.000. list bosanska krupa l33–117 (basic geological map of sfry 1:100,000. the bosanska krupa sheet).– institut za geološka istraživanja sarajevo (1964–1971), savezni geološki zavod beograd. mojičević, m., pamić, j., maksimčev, s. & papeš, j. (1979): osnovna geološka karta sfrj 1:100.000. tumač za list bosanska krupa l33–117 (basic geological map of sfry 1:100,000. geology of the bosanska krupa sheet).– geoinženjering sarajevo (1971), savezni geološki zavod beograd, 50 p. mrinjek, e. (1988a): sitnozrnati turbiditi cenomana u prelaznom pojasu unutrašnjih i vanjskih dinarida sjeveroistočno od slunja (fine-grained turbidites in the cenomanian of the transitional zone between inner and outer dinarides, ne of slunj).– geol. vjesnik, 41, 181–196. mrinjek, e. (1988b): sitnozrnati turbiditi i konturiti u dubokovodnim sedimentima gornje krede kod slunja i u žumberku (fine grained turbidites and conturites in the deep-water sediments of the upper cretaceous age near slunj and in žumberak).– zbornik radova 6. skup sediment. jugosl. titograd (proc. of the 6th meeting of sedimentologists of yugoslavia, titograd), geol. glasnik, posebna izd., 6, 135–149, titograd. nikler, l. (1978): stratigrafski položaj grebenskoga facijesa malma u sjevero-zapadnim dijelovima dinarida (stratigraphic position of the malmian reef facies in northwestern dinarids).– geol. vjesnik, 30/1, 137–150. ogorelec, b. & dozet, s. (1997): upper triassic, jurassic and lower cretaceous beds in eastern sava folds – section laze at boštanj (slovenia).– rud. metal. zbornik, 44/3–4, 223–235, ljubljana. ogorelec, b., šribar, l. & buser, s. (1976): o litologiji in biostratigrafiji volčanskega apnenca (on lithology and biostratigraphy of volče limestone).– geologija, 19, 125–151, ljubljana. 230 geologia croatica 55/2 231dragičević & velić: the northeastern margin of the adriatic carbonate platform orehek, s. & ogorelec, b. (1981): korelacija mikrofacialnih i geohemijskih osobina jurskih i krednih stena južne karbonatne platforme slovenije (correlation of microfacial and geochemical characteristics of jurassic and cretaceous rocks of the southern carbonate platform in slovenia).– glas. republ. zav. zašt. prirode – prirodnjačkog muzeja, 14, 161–181, titograd. papeš, j. (1972): osnovna geološka karta sfrj 1:100.000. list livno k33–11 (basic geological map of sfry 1: 100,000. the livno sheet).– geološki zavod sarajevo (1962–1967), savezni geološki zavod beograd. papeš, j. (1975): osnovna geološka karta sfrj 1:100.000. tumač za list livno k33–11 (basic geological map of sfry 1:100,000. geology of the livno sheet).– institut za geološka istraživanja sarajevo (1967), savezni geološki zavod beograd, 64 p. papeš, j. (1985): geologija jugozapadne bosne (geology of the southwestern bosnia).– geol. glasnik, pos. izd. (spec. publ.), 19, 197 p., sarajevo. pavšič, j. (1977): nanoplankton v zgornjekrednih in paleocenskih plasteh na goriškem (nannoplankton from the upper cretaceous and paleocene beds in the gorica region).– geologija, 20, 33–83. peza, l.h. & peza, e. (1994): the mesozoic development of the albanian alps carbonate systems and its relatioships with the cukali and kelmendi troughs.– géologie méditerranéenne, 21/3–4, 145–148. pleničar, m. (1958): poročilo o globokomorskem razvoju krednih plasti pri kostanjevici (report on the deep-sea development of the cretaceous beds at kostanjevica).– geologija, 4, 152–156, ljubljana. pleničar, m., premru, u. & herak, m. (1976): osnovna geološka karta sfrj 1:100.000. list novo mesto l33– 79 (basic geological map of sfry 1:100,000. the novo mesto sheet).– geološki zavod ljubljana (1963–1969), savezni geološki zavod beograd. polšak, a. (1981): upper cretaceous biolithitic complexes in a subduction zone: examples from the inner dinarids, yugoslavia.– in: toomey, d.f. (ed.): european fossil reef models. soc. econ. pal. mineral., spec. publ., 30, 447–472. polšak, a., juriša, m., šparica, m. & šimunić, an. (1977): osnovna geološka karta sfrj 1:100.000. list bihać l33–116 (basic geological map of sfry 1: 100,000. the bihać sheet).– institut za geološka istraživanja zagreb (1962–1967), savezni geološki zavod beograd. polšak, a., crnko, j., šimunić, an., šimunić, al., šparica, m. & juriša, m. (1978): osnovna geološka karta sfrj 1:100.000. tumač za list bihać l33–116 (basic geological map of sfry 1:100,000. geology of the bihać sheet).– institut za geološka istraživanja zagreb (1967), savezni geološki zavod beograd, 51 p. radoičić, r. (1966): microfaciès du jurasique des dinarides externes de la yougoslavie.– geologija, 9, 5–378, ljubljana. radoičić, r. (1989): the dinaric carbonate platform: adjacent basins and depressions.– mem. soc. geol. it., 40, 309–311. sofilj, j. & živanović, m. (1979): osnovna geološka karta sfrj 1:100.000. list prozor k33–12 (basic geological map of sfry 1:100,000. the prozor sheet).– institut za geološka istraživanja sarajevo (1965–1971), savezni geološki zavod beograd. sofilj, j., živanović, m. & pamić, j. (1980): osnovna geološka karta sfrj 1:100.000. tumač za list prozor k33–12 (basic geological map of sfry 1:100,000. geology of the prozor sheet).– institut za geološka istraživanja sarajevo (1971), savezni geološki zavod beograd, 49 p. sokač, b. (1964): geološki odnosi u području krstinja– cetingrad (geology of the krstinja–cetingrad area).– unpubl. msc. thesis, university of zagreb, 37 p. stampfli, g.m. & mosar, j. (1999): the making and becoming of apulia.– in: gosso, g., jadoul, f., sella, m. & spalla, m.i. (eds.): 3rd workshop on alpine geological studies. memorie di scienze geologiche, 51/1, 141–154, padova. šikić, k. & basch, o. (1975): geološka zbivanja od paleozoika do kvartara u zapadnom dijelu zagrebačke regije (geological events from paleozoic to quaternary in the western part of zagreb area).– 2. godišnji znanstveni skup sekcije za primjenu geol., geofiz., geokem., znanstveni savjet za naftu jazu zagreb (a), 5, 69–86. šikić, k., basch, o. & šimunić, a. (1978): osnovna geološka karta sfrj 1:100.000. list zagreb l33–80 (basic geological map of sfry 1:100,000. the zagreb sheet).– institut za geološka istraživanja zagreb (1972), savezni geološki zavod beograd. šikić, k., basch, o. & šimunić, a. (1979): osnovna geološka karta sfrj 1:100.000. tumač za list zagreb l33–80 (basic geological map of sfry 1:100,000. geology of the zagreb sheet).– institut za geološka istraživanja zagreb (1972), savezni geološki zavod beograd, 81 p. šinkovec, b. & babić, v. (1973): kemijski i mineralni sastav donjokrednih glinovitih boksita u planini grmeč (chemical and mineralogical composition of the lower cretaceous clayey bauxites of the grmeč mountain).– geol. vjesnik, 25, 245–253. šparica, m. (1981): mezozoik banije, korduna i dodirnog područja bosne (geology of the mesozoic areas of kordun, banija and nw bosnia, yugoslavia).– nafta, zagreb, spec. publ., xii+245 p. šribar, lj. (1965): meja med krednimi in terciarnimi skladi v goriških brdih (the boundary between cretaceous and tertiary in goriška brda).– geologija, 8, 121–129, ljubljana. tomić, v. (1985): prigrebenske i bazenske naslage senona u području donjeg bešpelja, sjeverno od jajca (peri-reefal and basin deposits of the senonian in the area of donji bešpelj, in the north of jajce).– geol. vjesnik, 38, 81–86. turnšek, d. (1966): zgornjejurska hidrozojska favna iz južne slovenije (upper jurasic hydrozoan fauna from southern slovenia).– razprave sazu, 9, 335–428, ljubljana. turnšek, d. (1997): mesozoic corals of slovenia.– zrc sazu, ljubljana, 513 p. turnšek, d. & buser, s. (1974): spodnjekredne korale, hidrozoji in hetetide z banjške planote in trnovskega gozda (the lower cretaceous corals, hydrozoans and cha232 geologia croatica 55/2 etetids of banjška planota and trnovski gozd).– razprave sazu, 17, 81–124, ljubljana. turnšek, d., buser, s. & ogorelec, b. (1981): an upper jurassic reef complex from slovenia, yugoslavia.– in: toomey, d.f. (ed.): european fossil reef models. soc. econ. pal. mineral. spec. publ., 30, 361–369. velić, i. (1977): jurassic and lower cretaceous assemblagezones in mt. velika kapela, central croatia.– acta geologica, 9/2, 15–37, zagreb. velić, i., vlahović, i. & matičec, d. (2002a): depositional sequences and palaeogeography of the adriatic carbonate platform.– mem. soc. geol. it., 57, 141–151. velić, i., tišljar, j., vlahović, i., velić, j., koch, g. & matičec, d. (2002b): palaeogeographic variability and depositional environments of the upper jurassic carbonate rocks of velika kapela mt. (gorski kotar area, adriatic carbonate platform, croatia).– geol. croatica, 55/2, 121–138. vrhovčić, j. & mojičević, m. (1983): osnovna geološka karta sfrj 1:100.000. tumač za list ključ l33–130 (basic geological map of sfrj 1:100,000. geology of the ključ sheet).– geoinženjering sarajevo (1976), savezni geološki zavod beograd, 40 p. vrhovčić, j., vujnović, l. & mojičević, m. (1983): osnovna geološka karta sfrj 1:100.000. list ključ l33– 130 (basic geological map of sfrj 1:100,000. the ključ sheet).– geoinženjering sarajevo (1969–1978), savezni geološki zavod beograd. vujisić, t. (1972): osnovna geološka karta sfrj 1: 100.000. list nikšić k34–38 (basic geological map of sfrj 1:100,000. the nikšić sheet).– zavod za geološka i geofizička istraživanja beograd (1962–1967), savezni geološki zavod beograd. vujisić, t. (1975): osnovna geološka karta sfrj 1:100.000. tumač za list nikšić k34–38 (basic geological map of sfrj 1:100,000. geology of the nikšić sheet).– zavod za geološka i geofizička istraživanja beograd (1967), savezni geološki zavod beograd, 53 p. vujnović, l. (1980): osnovna geološka karta sfrj 1: 100.000. list bugojno l33–143 (basic geological map of sfrj 1:100,000. the bugojno sheet).– geoinženjering sarajevo (1967–1975), savezni geološki zavod beograd. vujnović, l. (1981): osnovna geološka karta sfrj 1: 100.000. tumač za list bugojno l33–140 (basic geological map of sfrj 1:100,000. geology of the bugojno sheet).– geoinženjering sarajevo (1975), savezni geološki zavod beograd, 58 p. zappaterra, e. (1990): carbonate paleogeographic sequences of the periadriatic region.– boll. soc. geol. ital., 109, 5–20. zappaterra, e. (1994): source rock distribution model of the periadriatic region.– am. ass. petrol. geol. bull., 78/3, 333–354. zupanič, j. (1976): senonske naslage tipa scaglia u zapadnim dinaridima: postanak sedimenata, lateralne promjene i varijabilnost paleogeografskog značenja (genesis and lateral variability of senonian “scaglia type” sediments in western part of dinarids).– 8. jugosl. geol. kongr. bled (1974), 2, 335–341, ljubljana. živaljević, m., đokić, v. & pajović, m. (1971): osnovna geološka karta sfrj 1:100.000. list titograd k34–51 (basic geological map of sfrj 1:100,000. the titograd sheet).– zavod za geološka istraživanja titograd (1962–1967), savezni geološki zavod beograd. živaljević, m., vujisić, p. & stijović, v. (1989): osnovna geološka karta sfrj 1:100.000. tumač za list žabljak k34–27 (basic geological map of sfrj 1: 100,000. geology of the žabljak sheet).– zavod za geološka istraživanja titograd (1987), savezni geološki zavod beograd, 62 p. živanović, m., sofilj, j. & milojević, r. (1971): osnovna geološka karta sfrj 1:100.000. list zenica l33–144 (basic geological map of sfrj 1:100,000. the zenica sheet).– institut za geološka istraživanja sarajevo (1962–1967), savezni geološki zavod beograd. ab stra ct soil samples from the industrial area in the town of bužim, bosnia and herzegovina were analysed in order to determine their different manganese species. samples were extracted from seven locations – at the manganese mine and the surrounding area. the paper aims to present the use of the sequential extraction method in determination of the specifi c distribution of mn in soil, as well as in estimation of its origin, mobility and bioavailability in the sampling locations. sequential extraction used here included determination of the amount of mn in various soil fractions: the water-soluble fraction, exchangeable fraction, carbonate fraction, easily reduced fraction and the organic fraction. additionally, it included manganese oxides or moderately reduced oxides, amorphous iron oxide, crystalline iron oxide and the residual fraction. it was determined that chemical properties of soil considerably affect the distribution of heavy metals within different soil fractions. the highest percentage of natural mn was determined in the residual fraction (27.00%) at popović polje, while the highest percentage of anthropogenic origin mn was determined at bućevci (57.00%) in the fe-mn oxides fraction. the highest near-total content of mn was determined at popović polje (20950.00 mg/kg). the highest percentage of natural mn (27.00%) was determined in the same area. the highest percentage of mn of an anthropogenic origin (57.00%) was determined at bućevci. keywords: sequential extraction, manganese, manganese bioavailability, manganese mine „bužim“, manganese speciation, soil  distribution and bioavailability of manganese in soil in the vicinity of the „bužim“ abandoned mine  safeta redžić1, galiba sijarić1, tidža muhić-šarac2, ekrem pehlić1 and damir hrnjica1 1 university of bihać, biotechnical faculty bihać, bosnia and herzegovina; (corresponding author: safetabtf@gmail.com) 2 university of sarajevo, faculty of natural sciences and mathematics sarajevo, bosnia and herzegovina doi: 10.4154/gc.2014.04 geologia croatica 67/1 45–58 6 figs. 5 tabs. zagreb 2014 geologia croaticageologia croatica 1. introduction interest in the geochemical pattern of soil contamination has increased within the last few decades, due to the fact that soils serve as a depot for metals in an environment (warren & birch, 1987; li & thornton, 2001; oreščanin et al., 2003; martley et al., 2004). macklin (1992) provides a description of soil and sediment contamination by metals as a result of mining activities. an ever-growing number of research papers are directed towards the determination of soil contamination by manganese (piper, 1931; bromfield & david, 1987; hajda rević et al., 1988; marika & markku, 2003; rutten & gert, 2003; alvarez et al., 2006; marschner & rengel, 2003; mossop & davidson, 2003; nadaska et al., 2009; rouhollah & farzaneh, 2010; zakir & shikazono, 2011). horstmar (1851) conducted an early study investigating the infl uence of manganese content in soil on manganese content in plants. according to the research conducted by other researchers (mihaljević et al., 2003; saletović geologia croatica 67/1geologia croatica 46 figure 1: map of sample collection area near the manganese mine in „bužim“. a) http://www.360.ba/buzim360/ b) base from hodžić & abdurahmanović (1998) redžić et al.: distribution and bioavailability of manganese in soil in the vicinity of the „bužim“ abandoned mine geologia croatica 47 et al., 2011) mn has an important role in the efficient utilization of other nutrients in the soil. the total amount of mn in soils is 200-3000 ppm, where 0.10–1.00% is available to plants. in soils it generally originates from mno2, occurring in different oxides with oxidation states from +2 to +7 (nogales et al., 1997; zhang et al., 2012). the availability of mn greatly depends on the oxidation-reduction conditions of soil (piper, 1931., dolar & keeney, 1971; bromfield & david, 1987), being reduced in neutral and alkaline environments, and increasing with acidity as mn2+ reduces (vukadinović & lončarić, 1998). according to zhang et al. (2012) the acidity of soil may cause mn oxide minerals to dissolve and release a significant amount of mn ions in soil, therefore increasing the toxicity of soil for many plants. the aim of this research is to determine the specific distribution of mn and its origin, bioavailability (trudinger & swaine, 1979; perin et al., 1985; li et al., 1995) and the mobility (pertsemli & voutsa, 2007; mossop & davidson, 2003; hlavay et al., 2004; kalembkiewicz & sitarz-palczak, 2004; olayinka et al., 2011) of certain mn forms in soil at the „bužim“ mine and the surrounding area. the research included analysis of water-soluble species, exchangeable species, carbonate species, easily reduced species, organic species, manganese oxides or moderately reduced oxides, amorphous iron oxide, crystalline iron oxide and the residual fraction of mn in soil in order to determine how mining activity affected the amount and origin of mn in soil. therefore, the sequential extraction method was employed in this research (tessier et al., 1979; tessier & campbell, 1987; calmano et al., 1993; zoumis et al., 2001; filgueiras et al., 2002; sahuquillo et al., 2003; hlavay et al., 2004). the procedure of sequential extraction applied in this research is combined and modified according to the standardized procedure of sequential extraction in the european community bureau of reference (bcr), tessier et al. (1979, 1987), agnieszka & witold (2004), ming et al. (2008), silveira et al. (2006) and other references dealing with the same issues (kazi et al., 2005; pueyo et al., 2008; davidson et al., 2006; jose et al., 2006; kaasalainen & yli-halla, 2003; rouhollah & farzaneh, 2010). a modified procedure of sequential extraction includes the determination of mn bound to particular soil phases in nine fractions: water-soluble fraction, exchangeable fraction, carbonate fraction, easily reduced fraction, organic fraction, manganese oxides or moderately reduced oxides, amorphous iron oxide, crystalline iron oxide and the residual fraction of mn. the first three steps of sequential extraction provide further data on the bioavailability of metals (jain, 2004). 2. area of investigation the research was conducted in the farthest northeast part of bosnia and herzegovina in the town of bužim. bužim has a population of about 20.000 inhabitants. it borders with the towns of bosanska krupa (east), cazin (south), velika kladusa (west and north) and the republic of croatia (northeast). a well-known manganese mine in bosnia and herzegovina is located in bužim, but has been out of use since the war in bosnia and herzegovina. the area is characterised by slightly rounded and seldom angular hills. the lowest altitudes occur in the bužimica river valley (150m). this is an area of mildly continental and mountain climate. the manganese deposit is placed in a synclinal structure which extends in a northeast-southwest direction. it occurs where the volcanogenic-sedimentary series overlie dolomites and dolomitic limestone. the deposit is dark red in colour, due to the high manganese content. occasionally, greenish tufa and light grey kaolin rich marls can be observed. mojićević et al. (1984) determined the age of the sediments in the wider area of bužim, having discovered that these are composed of triassic, cretaceous, palaeocene, miocene, and pliocene-quaternary structures. figure 1. is a location and sampling scheme map of the collection area near the manganese mine in „bužim“ and the surrounding area. 3. materials and methods 3.1. sampling sample collection from the soil was conducted by means of the standard pedologic methods of soil sampling, as well as the open pit sampling with reference to iso 10381 procedures (iso, 2002). sampling was conducted by means of the standard pedologic equipment and tools, while the special attention was given to prevention of sample contamination. sample collection occurred at the end of march 2010 at the manganese mine „bužim“ and the surrounding area and a total of 10 soil samples from different locations have been used. four samples were collected from a soil profile close to the mine at different depths, i.e. from four horizons in loose and solid part using kopecky cylinders (figure 2). clearly visible sequences of genetic horizons have been observed during the process of sample collection from the soil profile at a depth of 100 cm. the four horizons are distinguishable at a 0-26 cm, 26-49 cm, 49-69 cm and 69-100 cm deep. a total of six ordinary loose samples were taken from the surrounding area of the mine at a depth of 0-25 cm. locations of these samples were: popović polje located 2.5-3 km north-west of the mine, rusija and bajraktarević polje (2 km to the south-west), varoška rijeka also 2.5 km southwest of the mine, radostovo (4 km to the south) and bućevci 7 km south-east of the mine. these locations were chosen in order to determine the distribution of manganese in horizontal profile at the surrounding area in relation to the manganese mine. 3.2. sample preparation and analysis the soil samples were prepared for physico-chemical analyses according to the iso 11464 procedure (iso 1994b). geologia croatica 67/1geologia croatica 48 soil samples used in the research were prepared and cleared of impurities (organic matter and visible shells), airdried, sifted with 2 mm hole diameter sieve, homogenised by the quartering method and sampled for laboratory analysis. samples prepared in this way were used for physical and chemical analysis of soil. a fragment of prepared samples was dried in dryer at a temperature of 105 °c for an hour, afterwards powdered in agate mortar according to the iso 11465 procedure (iso 1993). samples prepared in this way were used for determination of the near-total content of manganese in all samples, as well as for sequential extraction of manganese in the nine fractions. 3.3. methods of analysis samples were analysed by means of the following methods: – determination of the hygroscopic moisture content of the soil (hy) according to the iso 11465 procedure (iso 1993), – the mineral part of the soil was determined by calcination at 500-600 °c 2 h (čustovic & tvica, 2005), figure 2: layout of soil horizons in the soil profile. – determination of granulometric soil texture was conducted according to the iso 11277 procedure (iso 1998). the texture of soil samples was conducted according to ehwald (resulovic & čustović, 2002), – bulk density was determined according to the iso 11272 procedure (iso 1993), – particle density was determined according to the iso 11508 procedure (iso 1998), – total porosity (%) was calculated using the values of bulk density and particle density (pekeč et al., 2013). – amount of humus was determined by determination of organic carbon (c) by sulphocromic oxidation as prescribed by iso 14235 (iso 1998). a correction factor of 1.724 was used to calculate humus from organic c. – amount of carbonate in the soil was determined according to the iso 10693 procedure (iso 1995). redžić et al.: distribution and bioavailability of manganese in soil in the vicinity of the „bužim“ abandoned mine geologia croatica 49 – determination of soil ph value was conducted according to the iso 10390 procedure (iso 1994c), – sum of the absorbed base cations and hydrolytic acidity were determinedby kapenn’s method (čustović & tvica, 2005) – the total adsorption capacity (t) was calculated from the total adsorbed basic cations (s) and total adsorbed h+ ions (h). – the degree of base saturation was calculated from the proportions of base cations (s) relative to the total adsorption capacity (t) and was expressed as a percentage. – easily accessible phosphorus and potassiumin the soil, are determined through al-method (enger-riehmdomino) by ammonium lactate-acetic acid extractaction described by egner et al. (1960), – near -total mn content in the soil was determined by aas after digestion of soil samples in a microwave oven, – methods of mn sequential extraction of soil samples are presented in table 1. 3.3.1. method for determining the near-total mn content in soil samples near-total contents of mn in all soil samples were determined from their extracts (silveira et al., 2006). sample extracts were processed by microwave digestion with the addition of 6 ml hcl (36%) and 2 ml hno3 (65%) microwave technique on a marsxpress system (cem) according to the epa 3050 (usepa, 1996). the microwave digestion programme included two phases: first, 8 minutes at 160°c, and 1200w; and second 10 minutes at 160°c, and 1200w. after completion of digestion and cooling, extracts were filtered (whattman type 50 filter paper) in glass bottles of 50 ml and diluted with distilled water to the level line (mossop & davidson, 2003). extracts prepared in this way were stored at 4°c until further analysis by aas according to the procedures of iso 11047 (iso 1998). 3.3.2. methodology for the sequential extraction of manganese from the soil the defined steps and reagents used in the process of sequential extraction are shown in table 1. extracts from different soil fractions were separated by centrifugation at a speed of 3000 rpm for a period of 30 minutes, collected in polyethylene bottles and stored at 4 °c until analysis according to the references (agnieszka & witold, 2004; ming et al., 2008; silveira et al., 2006; kazi et al., 2005; pueyo et al., 2008; davidson et al., 2006; jose et al., 2006; kaasalainen & yli-halla, 2003; rouhollah & farzaneh, 2010). the extracts from the residual fractions were processed by microwave digestion using the same procedure as for determination of the near-total content of manganese in soil samples. manganese concentrations in acidic residues were measured by atomic absorption spectrophotometer (zeeman, varian), using a calibration curve method (li et al., 2000). 3.3.3. quality assurance and quality control (qa/qc) quality assurance (qa) of the research has been realised by means of the appropriate laboratory facilities, specialised work procedures, use of distilled water, high-purity chemicals, and measurements conducted on the equipment with satisfying performance (analytical scales, ph meter, aas). quality control (qc) has been realised by an analysis of the relevant blind experiments, calibration of the equipment using standardised solutions, and repetition of the analyses using the same methodology with reference to iso 17025 procedures (iso, 2005). 4. results and discussion 4.1. physical and chemical soil analysis the determined values of specific physical and chemical soil properties are shown in tables 2 and 3. research has shown that particle density decreases in a vertical soil profile with table 1: sequential extraction of mn from soil. step fraction reagents references 1. water-soluble 30 ml distilled water (agnieszka & witold, 2004) 2. exchangeable fraction 20 ml 1 m cacl2 (ph=7) (agnieszka & witold, 2004; ming et al., 2008) 3. carbonate fraction 20 ml 1 mnaoac (ph=5 adjusted with hoac) (ming et al., 2008; silveira et al., 2006; kazi et al., 2005, baeyens et al., 2003) 4. easily reduced substances 40 ml 0.04 m nh2oh · hcl (ph=2 adjusted with ch3cooh) (ming et al., 2008; pueyo et al., 2008; davidson et al., 2006; jose et al., 2006; kaasalainen & yli-halla, 2003) 5. organic fraction 20 ml 1 m na4p2o7 (rouhollah & farzaneh, 2010) 6. manganese oxides or moderately reduced oxides 40 ml 0.05 m nh2oh/hcl (ph=2) (ming et al., 2008; silveira et al., 2006) 7. amorphous iron oxide 30 ml 2 m (h2c2o4) +0.2 m (nh4)2c2o4(ph = 3) (ming et al., 2008;silveira et al., 2006) 8. crystalline iron oxide 20 ml 6m hcl (ming et al., 2008) 9. residue (residual fraction) hcl : hno3 (3:1) microwave digestion usepa, 1996 (silveira et al., 2006) geologia croatica 67/1geologia croatica 50 increasing depth, i.e. from 2.51 g/cm3 in the 1st horizon to 2.30 g/cm3 in the 4th horizon. bulk density displays different values within horizons of the vertical soil profile. the average amount in the 1st horizon is 1.46 g/cm3, 1.44 g/cm3 in the 2nd, 1.49 g/cm3 in the 3rd, and 1.41 g/cm3 in the 4th horizon. based on the particle density and bulk density, it is possible to determine whether the soil is arable compacted soil. based on the research of soil porosity we determined soil with low porosity, with a total amount of pore space of 38.60% in 4th horizon to 43.50% in 2nd horizon. the results of granulometric analysis indicate that samples from the 2nd and 3rd horizons of the vertical profile are similar in granulometric properties and can be regarded as a clay loam. samples taken from the locations surrounding the manganese mine (popović polje, rusija, bajraktarević polje, varoška rijeka, radostovo and bućevci) at depth of 0-25 cm displayed similar granulometric properties, which are: sandy loaml, loam, loamy sand and silty sand. this can be regarded as being caused by intensive deep erosion. the soils ph values range from moderately acidic to mildly alkaline, from ph=4.64 at the manganese mine location in the deepest horizon to ph=7.26 at the location of varoška rijeka. at different horizons in vertical profile, ph value decreases from the 1st to 4th horizons. all soil samples displayed lower ph values of kcl than the ph values of h2o, especially in soils where ph value is usually high. soils with delta ph higher than 0.10, are said to have geric properties, i.e. are very exposed to erosion and have low adsorption capacity or a low number of exchangeable bases (resulović, 1997). delta ph had the highest value (ph=0.65) at the 4th horizon (100 cm) at the manganese mine. the amount of caco3 in all samples was lower than the limit set by the method, since the dissolution of soil samples was conducted by using diluted hydrochloric acid. based on the results of research and values obtained for the level of base saturation (v), ranging from 73.58% at popović polje to 99.47% at varoška rijeka, it can be stated that all tested locations are eutric cambisols. 4.2. near-total content of manganese the near-total content of manganese for each sample location in the vertical profile are presented in table 4, as well as for each sample location surrounding the „bužim“ mantable 2: physical properties of soil. soil test / sample particle density (kgdm–3) bulk density (kgdm–3) total porosity (%) particle content in soil (%) textural types according to hwald size of particles in (mm) 0.02–2.00 sand 0.002–0.02 silt < 0.002 clay a b c d mine section 1st horizon (0-26 cm) 2.51 1.46 41.80 37.50 42.50 20.00 loam mine section 2nd horizon (26-49 cm) 2.55 1.44 43.50 30.70 38.00 31.30 clay loam mine section 3rd horizon (49-69 cm) 2.46 1.49 39.40 30.80 35.80 33.40 clay loam mine section 4th horizon (69-100 cm) 2.30 1.41 38.60 12.50 16.20 71.30 clay popović polje (0-25 cm) – – – 47.40 37.70 14.90 sandy loam rusija (0-25 cm) – – – 33.20 47.40 19.40 loam bajraktarević polje (0-25 cm) – – – 45.90 45.00 9.10 sandy loam varoška rijeka (0-25 cm) – – – 80.30 17.20 2.50 loamy sand radostovo (0-25 cm) – – – 39.20 49.40 11.40 sandy loam bućevci (0-25 cm) – – – 73.30 22.10 4.60 silty sand redžić et al.: distribution and bioavailability of manganese in soil in the vicinity of the „bužim“ abandoned mine geologia croatica 51 ta bl e 3: c he m ic al p ro pe rt ie s o f s oi l. so il te st / sa m pl e ph -v a lu e in (1 :2 .5 ) h ig ro sc o pi c h u m id it y (t= 10 5° c) (% ) re si d u e a ft er ca lc in at io n (t= 55 0° c) (% ) am o u n t o f h u m u s (% ) am o u n t o f ph ys io lo g ic a l ac ti vi ty (m g/ 10 0 g of so il) am o u n t o f ca co ₃ ( % ) h yd ro ly ti c ac id it y „h “ (m m ol /1 00 g of so il) am o u n t o f a lk a li n e a d so rp tio n „s “ ( m m ol / 10 0g o f s oi l) to ta l a d so rp ti o n ca pa ci ty „t “ (m m ol / 1 00 g of so il) d eg re e o f a lk a li -n e sa tu rat io n „v “ (% ) h ₂o kc i p₂ o ₅ k₂ o a b c d e f g h j m in e se ct io n 1 st h or iz on (0 -2 6 cm ) 5. 53 5. 29 2. 17 91 .6 3 2. 65 < 0. 10 10 .5 2 < 0. 10 1. 50 8. 77 10 .2 7 85 .4 0 m in e se ct io n 2 nd h or iz on (2 649 c m ) 5. 46 5. 45 2. 25 93 .5 5 0. 64 < 0. 10 6. 75 < 0. 10 0. 75 5. 98 6. 73 88 .8 5 m in e se ct io n 3 rd h or iz on (4 969 c m ) 5. 34 5. 14 2. 41 93 .7 4 0. 47 < 0. 10 7. 01 < 0. 10 0. 75 5. 58 6. 33 88 .1 6 m in e se ct io n 4 th h or iz on (6 910 0 cm ) 4. 64 3. 99 4. 22 89 .6 2 0. 47 < 0. 10 6. 66 < 0. 10 1. 35 5. 58 6. 93 80 .5 3 po po vi ć po lje (0 -2 5 cm ) 5. 23 4. 85 2. 97 87 .0 7 3. 52 < 0. 10 17 .9 8 < 0. 10 3. 15 8. 77 11 .9 2 73 .5 8 ru si ja (0 -2 5 cm ) 5. 79 5. 42 2. 68 89 .5 0 4. 15 < 0. 10 21 .6 6 < 0. 10 2. 10 9. 97 12 .0 7 82 .6 0 ba jra kt ar ev ić p ol je (0 -2 5 cm ) 6. 76 6. 55 2. 02 91 .6 7 2. 33 < 0. 10 7. 71 < 0. 10 1. 50 27 .9 4 29 .4 4 94 .9 0 va ro šk a rij ek a (0 -2 5 cm ) 7. 26 7. 21 1. 41 91 .9 2 3. 36 7. 22 12 .3 6 < 0. 10 0. 45 85 .4 5 85 .9 0 99 .4 7 ra do st ov o (0 -2 5 cm ) 6. 99 6. 56 2. 26 90 .9 3 3. 48 2. 88 21 .9 2 < 0. 10 0. 75 15 .5 6 16 .3 1 95 .4 0 bu će vc i (0 -2 5 cm ) 7. 08 7. 06 3. 15 89 .1 1 3. 07 < 0. 10 15 .4 3 < 0. 10 0. 75 39 .1 2 39 .8 7 98 .1 0 geologia croatica 67/1geologia croatica 52 ganese mine. relatively equable mn concentrations were measured through all horizons, at three depths of the vertical profile, ranging from 1190.00 to 1160.00 mg/kg with increasing depth. table 4: near-total content of mn for each sample location. symbols of samples amount mn (mg/kg) m in e se ct io n 1st horizon (0-26 cm) 1190.00 2nd horizon (26-49 cm) 1170.00 3rd horizon (49-69 cm) 1160.00 4th horizon (69-100 cm) 780.00 (0-25 cm) rusija (0-25 cm) bajraktarević polje (0-25 cm) varoška rijeka (0-25 cm) radostovo (0-25 cm) bućevci (0-25 cm) the amount of mn was significantly decreased at the 4th horizon (780.00 mg/kg), as displayed in figure 3. figure 4. indicates that within the examination of all locations at a depth of 0-25 cm, the highest near-total content of 20950.00 mg/kg of mn, was measured at the area of popović polje, while the lowest amount was measured at the area of bućevci of 418.00 mg/kg. the high content of mn in certain locations is probably due to the close proximity of the sampling areas to the mine. results indicate that, the sample locations contain extremely high concentrations of manganese, which can be related to the former mining activities in the area. 4.3. the distribution of mn in different soil fraction determined from sequential extraction table 5. presents the mn contents in the individual fractions as determined by the process of sequential extraction. the sum of all the examined mn fractions displays relatively good correlation with near-total content of mn at the same soil samples, while this type of correlation was not displayed at the area of popović polje. according to zemberyova et al. (2006) figures 5 and 6 display the extracted percentages of mn among the examined fractions (in relation to the certified value of 100). meers et al. (2007) define the water-soluble fraction as being easily mobilised and a highly available fraction. in the first soluble fraction, the percentage of mn in the vertical profile of horizons at the manganese mine location is lower than 1.00%, thus posing no threat according to the assessment code. the percentage of soluble fraction in soil samples from the area surrounding manganese mine at all sampling locations is lower than 1.00%, thus having no detrimental effect on the environment. the exchangeable metal fraction is loosely bound to colloidal soil particles (agnieszka & witold, 2004). novozamski et al. (1993) proposed the use of cacl2 as a reagent for evaluation of metal and nutrient bioavailability in air-dried soil sample. houba et al. (1996, 2000) state the advantages of this reagent. in the second exchangeable fraction, the percentage of mn in the vertical profile (sampled in the mine) is as follows: 2.00 % in 1st horizon, 1.00% in the 2nd and 3rd horizon and 3.00 % in the 4th horizon. the highest percentage of the exchangeable manganese fraction is obtained in the 4th horizon, probably due to an increased ionic exchange which occurs as the soil depth and amount of cations in the soil increase. the percentage of exchangeable fractions at locations surrounding the manganese mine (1st horizon) is as follows: <0.10% in popović polje and bajraktarević polje, 2.00% in rusija and varoška rijeka, 1.00% in radostovo and bućevci. the percentage of mn in the exchangeable fraction (mobile metal fraction) at all sample locations, according to the assessment code, has no detrimental effect on the environment. the carbonate fraction is regarded as an easily mobilised fraction. extraction within this fraction was conducted by means of reagent 1m naoac solution, ph=5 adjusted with acetic acid in order to transfer most of the absorbed mn into solution (baeyens et al., 2003), as the fraction is highly sensitive to changes of ph value (tessier et al., 1979). figure 3: near-total content of mn at the mining area. figure 4: near-total content of mn in the surrounding area. redžić et al.: distribution and bioavailability of manganese in soil in the vicinity of the „bužim“ abandoned mine geologia croatica 53 ta bl e 5: t he a m ou nt o f m n in c er ta in fr ac tio ns a ft er se qu en tia l e xt ra ct io n pr oc ed ur e (m g/ kg ). sa m pl e / fr ac ti o n m in e se ct io n po po vi ć po lje (0 -2 5 cm ) ru si ja (0 -2 5 cm ) ba jra kt ar ev ić po lje (0 -2 5 cm ) va ro šk a rij ek a (0 -2 5 cm ) ra do st ov o (0 -2 5 cm ) bu će vc i (0 -2 5 cm ) 1s t h or iz on (0 -2 6 cm ) 2n d ho riz on (2 649 c m ) 3r d ho riz on (4 969 c m ) 4t h ho riz on (6 910 0 cm ) w at er -s ol ub le fra ct io n 1. 50 1. 50 1. 50 1. 50 0. 60 0. 90 0. 90 0. 90 1. 20 0. 90 ex ch an ge ab le fra ct io n 29 .2 0 8. 40 8. 60 17 .4 0 56 .8 0 17 .8 0 10 .4 0 8. 60 15 .2 0 5. 20 ca rb on at e fra ct io n 31 .8 0 8. 80 7. 40 9. 20 52 .8 0 22 .4 0 48 .6 0 52 .8 0 34 .8 0 42 .6 0 ea si ly re du ce d su bs ta nc es 39 3. 60 18 1. 60 16 2. 00 18 6. 80 29 16 .0 0 92 .8 0 26 44 .0 0 20 7. 20 21 7. 20 25 5. 60 o rg an ic fra ct io n 99 2. 00 51 6. 00 55 6. 00 18 3. 00 52 00 .0 0 42 4. 00 26 00 .0 0 40 .0 0 50 5. 00 48 .0 0 m an ga ne se ox id es 15 8. 00 67 .2 0 74 .4 0 34 .4 0 28 32 .0 0 73 .2 0 78 4. 00 17 .6 0 70 .8 0 19 .6 0 am or ph ou s i ro n ox id e 48 .3 0 47 .7 0 50 .7 0 21 .0 0 26 64 .0 0 41 .1 0 12 96 .0 0 8. 40 56 .7 0 9. 30 cr ys ta lli ne ir on ox id e 80 .2 0 86 .0 0 91 .2 0 52 .0 0 58 80 .0 0 63 .8 0 90 0. 00 67 .6 0 67 .2 0 38 .0 0 re si du al a m ou nt of m n 14 7. 00 16 8. 50 14 9. 50 12 4. 50 71 25 .0 0 11 4. 50 52 0. 00 29 .5 0 17 8. 50 41 .0 0 to ta l a m ou nt o f fra ct io ns 18 81 .6 0 10 85 .7 0 11 01 .3 0 62 9. 80 26 72 7. 20 85 0. 50 88 03 .9 0 43 2. 60 11 46 .6 0 46 0. 20 geologia croatica 67/1geologia croatica 54 according to robbins et al. (1984) the reagent releases 99.90% of the carbonate fraction and has minimum influence on other fractions. the percentage of carbonate fraction in vertical profile (sampled in the mine) of horizons ranges from 1.00% in 2nd, 3rd and 4th horizon, to 2.00% in 1st horizon, thus posing low risk to the environment according to the assessment code. the highest percentage of carbonate fraction in the 1st horizon can be explained by the susceptibility of the fraction to changes of ph value (tessier et al., 1979). consequently, it was observed that the highest percentage of carbonate fraction correlates with the highest measured ph value (5.53) at the 1st horizon soil sample in the vertical profile in the area of the mine. the percentages of carbonate fraction at the other sample locations surrounding the manganese mine (1st horizon) are: <0.10% in popović polje, 3.00% in rusija, 1.00% in bajraktarević polje, 12.00 % in varoška rijeka, 3.00% in radostovo and 9.00% in bućevci. the highest percentage of the carbonate fraction was detected at the location of varoška rijeka (12.00%) correlating with the highest measured ph value at the same location (7.26), which confirms the fact that the fraction is susceptible to changes of ph value. moreover, it proves the sensitivity of the fraction to changes of ph-value and indicates that as the soil ph value increases, so does the percentage of carbonate and consequently of the bioavailable manganese fraction in the soil. the percentage of mn in the carbonate soil fraction at the location of varoška rijeka has a limited effect on the environment. easily reduced substances (fe-mn bound oxides) display moderate mobility, depending on the redox conditions of the environment. according to silvera et al. (2006) the redox potential of soil can significantly increase the solubility of fe and mn oxides. fe and mn oxides have a great effect on control and mobility of other metals in the environment. in the reduced fraction (fe-mn bound oxides), the percentages of mn in the vertical profile (sampled in the mine) of individual horizons are: 1st horizon 21.00%, 2nd horizon 17.00%, 3rd horizon 15.00% and 4th horizon 31.00%. the highest percentage of figure 5: distribution of mn at the mining area using the sequential extraction procedure. figure 6: distribution of mn in the area surrounding the mine using sequential the extraction procedure. mn in the vertical profile was determined at the 4th horizon (31.00%), which could be due to an increased redox potential there, leading to an increased solubility of the fraction. the highest percentage of mn in this fraction correlates with the lowest measured ph value at the 4th horizon. percentages of the reduced fraction at the locations surrounding the manganese mine (1st horizon) are: popović polje and rusija 11.00%, bajraktarević polje 29.00%, varoška rijeka 48.00%, radostovo 19.00% and bućevci 57.00%. the percentage of the reduced fraction at all sample locations is relatively high, due to numerous natural and anthropogenic sources of mn over the area. the highest percentage of the easily reduced fraction is determined in the area of bućevci (57.00%), which can be explained by manganese oxidation resulting from mining activity there (nadaska et al., 2009).the fact that mn dominates in the fraction of fe-mn oxide at the area of bućevci indicates they share a common origin. according to haung et al. (2007) mn bound to the organic fraction displays moderate mobility, although it can be increased due to the oxidation of organic matter. the solubility of the mn fraction bound to organic matter, precedes those of mn oxides, amorphous and crystalline iron oxides. this enables organic phase degradation, providing better conditions for the extraction of fractions bound to mn (alvarez et al., 2006). the percentage of the organic fraction in the vertical profile (sampled in the mine) of individual horizons is: 1st horizon 52.00%, 2nd horizon 47.00%, 3rd horizon 49.00% and 4th horizon 29.00%. the percentage of the organic fraction at sample locations surrounding the „bužim“ manganese mine (1st horizon) is: popović polje 19.00%, rusija 49.00%, bajraktarević polje 30.00%, varoška rijeka 9.00%, radostovo 44.00% and bućevci 10.00%. due to a high affinity of bonding to organic matter (resulović, 1997) mn is dominant in this fraction with the highest percentage (52.00%) in the 1st horizon of the vertical profile (sampled in the mine). the percentage of manganese oxides or moderately reduced oxides in horizons of vertical profiles (sampled in the redžić et al.: distribution and bioavailability of manganese in soil in the vicinity of the „bužim“ abandoned mine geologia croatica 55 mine) is: 1st horizon 8.00%, 2nd horizon 6.00%, 3rd horizon 7.00% and 4th horizon 5.00%. the percentage of this fraction at other locations surrounding the manganese mine (1st horizon) is: popović polje 11.00%, rusija i bajraktarević polje 9.00%, varoška rijeka and bućevci 4.00%, radostovo 6.00%. the highest percentage of the fraction was measured at the popović polje location (11.00%), which can be related to relatively low ph-values of the location (5.23) (silveira et al., 2006). the percentage of mn bound to the amorphous iron oxide fraction in the horizons of the vertical profile (sampled in the mine) is:1st and 4th horizon 3.00%, 2nd horizon 4.00% and 3rd horizon 5.00%. at locations surrounding the manganese mine (1st horizon) it is as follows: popović polje 10.00%, rusija 5.00%, bajraktarević polje 15.00%, varoška rijeka and bućevci 2.00% and radostovo 5.00%. the highest percentage of this fraction is measured in the area of bajraktarević polje (15.00%). schwertmann (1991) proved the efficacy of 6 m hcl used for dissolution of the crystalline iron oxide fraction. in his research, the author stated that nearly 60.00% of fe dissolves with 6m hcl solution (silviera et al., 2006). the percentage of mn bound to the crystalline iron oxide fraction in individual horizons of vertical profile (sampled in the mine) is determined as: 1st horizon 4.00%, 2nd, 3rd and 4th horizon 8.00%. at locations surrounding the manganese mine (1st horizon) it is as follows: popović polje 22.00%, rusija 8.00%, bajraktarević polje 10.00%, varoška rijeka 16.00%, radostovo 6.00% and bućevci 8.00%. the highest percentage of the fraction was measured in the popović polje (22.00%). the highest percentage of mn in this fraction correlates with the highest percentage in manganese oxides and moderately reduced oxides fraction, which can be due to the size of their ionic radii and isomorphic substitution of mn and fe (silveira et al., 2006). according to sutherland et al. (2000), metals extracted in non-residual fractions indicate an anthropogenic origin, and metals extracted in the residual fraction indicate a natural origin (forstner, 1983; blasco et al., 2000; jain, 2004; ramirez et al., 2005). prica (2011) states that the residual fraction cannot be mobilised from geological material and is not bioavailable. the percentage of the residual fraction in horizons of the vertical profile (sampled in the mine) is: 1st horizon 8.00%, 2nd horizon 16.00%, 3rd horizon 14.00% and 4th horizon 20.00%. at locations surrounding the manganese mine (1st horizon) it is as follows: popović polje 27.00%, rusija 13.00%, bajraktarević polje 6.00%, varoška rijeka 7.00%, radostovo 16.00% and bućevci 9.00%. a rather high percentage of mn at the aforementioned locations is probably due to extremely strong bonds of mn and the soil solid phase. the highest percentage of the fraction is determined at the area of popović polje (27.00%). the highest percentage of mn in this fraction in the area correlates with the crystalline iron oxide fraction and mn oxide and moderately reduced oxide fraction. 5. conclusions according to the research conducted at the „bužim“ manganese mine and the surrounding area, the following conclusions can be drawn: according to ph values the soils are moderately acidic to mildly alkaline, thus being considered as eutric cambisols. the results of sequential extraction indicate that chemical soil properties significantly affect mn distribution in the different soil fractions. the highest percentage of bioavailable mn was measured at the „bužim“ manganese mine (in 1st fraction) and in popović polje (in 2nd fraction), since there are numerous natural and anthropogenic sources of mn at these areas. the percentage of mn soluble fraction is less than 1.00% at all locations, thus having no detrimental effect on the environment. the highest percentage of exchangeable manganese fraction (3.00%) was measured in the 4th horizon of the vertical profile, probably due to an increased ionic exchange which occurs as depth increases, thus having no detrimental effect on the environment according to the assessment code. the highest percentage of the carbonate fraction (12.00%) was determined at the location of varoška rijeka correlating with ph=7.26. the percentage of mn in the carbonate fraction at the location of varoška rijeka moderately affects the environment. the highest percentage of natural mn was determined in the residual fraction (27.00%) at popović polje, while the highest percentage of anthropogenic origin mn was determined at bućevci (57.00%) in the fe-mn oxides fraction. the highest near-total content of mn was determined at popović polje (20950.00 mg/kg). the highest percentage of natural mn (27.00%) was determined in the same area. the highest percentage of mn of an anthropogenic origin (57.00%) was determined at bućevci. the results are possibly due to mining activity which took place there in the past. further research shall be directed towards additional techniques such as x-ray analysis, which is highly important in the research of mineral phases enabling the determination of any correlation between certain chemical forms (species) of mn at the aforementioned soil areas. acknowledgement we would like to acknowledge the help in sample collection and soil analysis, provided by the director of the agricultural institute of una-sana canton and head of laboratory muhamed ajaz. references agnieszka, m. & witold, w. (2004): three-step extraction procedure for determination of heavy metals availability to vegetables.– anal. bioanal. chem., 380, 813–817. alvarez, j.m., luis, m., valdivia, l., novillo, j., obrador, a. & rico, m. (2006): comparison of edta and sequential extraction tests for phytoavailability prediction of manganese and zinc in agricultural alkaline soils.– geoderma, 132, 450–463. baeyens, w., monteny, f., leermakers, m. & bouillon, s. (2003): evalution of sequential extractions on dry and wet sediments.– anal. bioanal. chem., 376, 890–901. geologia croatica 67/1geologia croatica 56 blasco, j., saenz, v. & gomez-parra, a. (2000): heavy-metal fluxes at the sediment-water interface of three coastal ecosystems from south-west of the iberian peninsula.– science of the total environment, 247, 189–199. bromfield, s.m. & david, d.j. (1987): properties of biologically formed manganese oxide in relation to soil manganese.– australian journal of soil research,16, 79–89. calmano, w., hong, j. & förstner, u. (1993): binding and mobilisation of heavy metals in contaminated sediments affected by ph and redox potential.– water science and technology, 28/8–9, 223–35. custovic, h. & tvica, m. (2005): praktikum za pedološka istraživanja, univerzitet u sarajevu poljoprivredni fakultet. davidson, c.m., urquhart, g.j., ajmone-marsan, f., biasioli, m., da costa, d., armando, (?)., díaz-barrientos, e., grčman, h., hossack, i., hursthouse, a.s., madrid, l., rodrigues, s. & zupan, m. (2006): fractionation of potentially toxic elements in urban soils from five european cities by means of a harmonised sequential extraction procedure.– analytica chimica acta, 565, 63–72. dolar, s.g. & keeney, d.r. (1971): availability of cu, zn and mn in soils: influence of soil ph, organic matter, and extractable phosphorus.– journal of the science of food and agriculture, 22/6, 273–278. egner, h., riehm, h. & domino, w.r. (1960) untersuchungen uber die chemische bodenanalyse als grundlage fur die beurteilung des nahrstoffzustandes der boden, ii: chemische extractionsmetoden zu phosphorun kaliumbestimmung.– kungliga lantbrukshugskolansannaler, 26, 199–215. filgueiras, a.v., lavila, i. & bendicho, c. (2002): chemical sequential extraction for metal partitioning in environmental solid samples.– j. environ. monit., 4, 823–857. forstner, u. (1993): metal speciation: general concepts and applications. an account for the improvement and harmonisation of extraction techniques undertaken under the auspices of the bcr of the commission of the european communities.– international journal of environmental analytical chemistry, 51, 5–23. hajdarević, s., sijarić, g., vujnović, d. & šibenikstuden, m. (1988): manganonosno područje uzolomca i gorja.– zbornik ref. naučnogskupa ‘’minerali, stijene, izumrli i živi svijet bih’’. zemaljski muzej bih, 49–61. haung, j., haung, r., jiao, jj. & chen, k. (2007): speciation and mobility of heavy metals in mud, in coastal reclamation areas in chenzhen, china.– environ geol., 53, 221–228. hlavay, j., prohaska, t., weisz, m., wenzel, w.w. & stinngeder, g.j. (2004): determination of trace elements bond to soils and sediment fractions.– pure and applied chemistry, 76/2, 415–442. hodžić, t. & abdurahmanović, a. (1998): školski atlas ip "svjetlost" dd. zavod za udžbenike i nastavna sredstva, sarajevo, 1999. bih. horstmar, p.s. (1851): sur la nutrition de l’avoine, particulierement en ce qui concerne les matieresinorganiques qui sontnecessaires a cette nutrition.– ann. chim. phys., 32, 461–510. houba, v.j.g., lexmond, t.m., novozamsky, i. & van der lee, j.j. (1996): state of the art and future developments in soil analysis for bioavailability assessment.– the science of the total environment., 178, 21–28. houba, v.j.g., temminghoff, e.j.m., gaikhorst, g.a. & van vark,w. (2000): soil analysis procedures using 0.01 m calcium chloride as extraction reagent.– communications in soil science and plant analysis., 3, 1299–1396. iso – international standard organisation (2002): soil quality – sampling – part 1: guidance on the design of sampling programmes. iso 10381-1:2002 iso – international standard organisation (2002): soil quality – sampling part 2: guidance on sampling techniques. iso 103812:2002. iso – international standard organisation (1994): soil quality pretreatment of samples for physico-chemical analyses. iso 11464: 1994 (1994b). iso – international standard organisation (1995): soil quality – determination of carbonate content-volumetric method. iso 10693: 1995. iso – international standard organisation (1993): soil quality – determination of dry matter and water content on a mass basis – gravimetric method. international organization for standardization. geneva, switzerland. 9 p. iso 11465:1993. iso – international standard organisation (1994): soil quality – pretreatment of samples for physico-chemical analysis. international organization for standardization. geneva, switzerland. 9 p. iso 11464 :1994. iso – international standard organisation (1993): soil quality – determination of dry bulk density. international organization for standardization. geneva, switzerland. 10 p. iso 11272:1993. iso – international standard organisation (1998): soil quality – determination of particle density. iso 11508:1998. iso – international standard organisation (1998): determination of cadmium, chromium, cobalt, copper, lead, manganese nickel and zinc. flame and electrothermal atomic absorption spectrometric methods. international organization for standardization. geneva, switzerland. 6 p. iso 11047:1998. iso – international standard organisation (1998): soil quality – determination of organic carbon by sulphochromic oxidation. iso 14235: 1998. iso – international standard organisation (1998): determination of particle size distribution in mineral soil material. method by sieving and sedimentation. iso 11277:1998. iso – international standard organisation (2005): general requirements for the competence of testing and calibration laboratories. iso/iec 17025:2005. jain, c. k. (2004): metal fractionation study on bed sediments of river yamuna, india.– water research, 38, 569–578. jose, m.a., luis, m.l., jesus, n., ana, o. & maria, i.r. (2006): comparison of edta and sequential extraction tests for phytoavailability prediction of manganese and zinc in agricultural alkaline soils.– geoderma, 132, 450–463. kalembkiewicz, j. & sitarz-palczak, e. (2004): validation and optimization of condition for the sequential extraction of manganese from ash.– polish journal of environmental studies, 14, 41–47. kazi, t.g., jamali, m.k., kazi, g.h., arain, m.b., afridi, h.i. & siddiqui, a. (2005): evaluating the mobility of toxic metals in untreated industrial wastewater sludge using a bcr sequential extraction procedure and a leaching test.– anal. bioanal. chem., 383, 297–304. kaasalainen, m. & yli-halla, m.(2003): use of sequential extraction to assess metal partitioning in soils.– environmental pollution, 126, 225–233. li, w., peters, r.w., brewster, m.d. & miller, g.a. (1995): sequentinial extraction evaluation of heavy-metal-contaminated soil: how clean is clean? – proceedings of the air and waste management asociation. 88th annual meeting and exhibition, san antonio, texas. june, 18–23. li, x., shen, z., wai, o. & li, y-s. (2000): chemical partitioning of heavy metal contaminants in sediments of the pearl river estuary.– chemistry speciation bioavailability, 12/1, 17–25. li, x. & thornton, i. (2001): chemical partitioning of trace and major elements in soils contaminated by mining and smelting activiredžić et al.: distribution and bioavailability of manganese in soil in the vicinity of the „bužim“ abandoned mine geologia croatica 57 ties.– applied geochem., 16, 1693−1706. doi: 10.1016/s0883-2927 (01)00065-8. marika, k. & markku, y-h. (2003): use of sequential extraction to assess metal parttitioning in soil.– environmental pollution, 126, 225–233. macklin, m.g. (1992): metal contaminated soils and sediment: a geographical perspective.– in: newson, m.d. (ed.): managing the human impact on the natural environment: patterns and processes. belhaven press, london, 172−195. martley, e., gulson, b., louie, h., wu, m. & di, p. (2004): metal partitioning in soil profi les in the vicinity of an industrial complex, new south wales, australia.– geochem. explor. env., a4, 171−179. doi: 10.1144/1467-7873/03-030. marschner, p., fu, q. & rengel, z. (2003): manganese availability and microbial populations in the rhizosphere of wheat genotypes differing in tolerance to mn deficiency.– journal of plant nutrition and soil science, 166/6, 712–718. mihaljevič, m., poňavič, m., ettler, v. & šebek, o. (2003): a comparison of sequential extraction techniques for determining arsenic fractionationin synthetic mineral mixtures.– anal. bioanal. chem., 377, 723–729. ming, l., bo-han, l., qing-ru, z., pu-feng, q. & sardar, k. (2008): fraction distributions of lead, cadmium, copper, and zinc in metal-contaminated soil before and after extraction with disodium ethylenediaminetetraacetic acid.– communications in soil science and plant analysis, 39, 1963–1978. mojićević, m., čačić, s. & papeš, j. (1984): geologija bosne i hercegovine, knj. ii mezozojske periode „geoinženjering“ sarajevo. mossop, k.f. & davidson, c.m. (2003): comparison of original and modified bcr sequential extraction procedures for the fractionation of copper, iron, lead, manganese and zinc in soils and sediments.– analitica chimica acta, 478, 111–118. meers, e., laing, g., unamuno, v., ruttens, a., vangronsveld, j., tack, f.m.g. & verloo, m.g. (2007): comparison of cadmium extractability from soils bycommonly used single extraction protocols.– geoderma, 141, 247–259. nadaska, g., polčova, k. & lesny, j. (2009): manganese fractionation analysis in specific soil and sediment samples.– nova biotechnologica, 9–3. nogales, r., gallardo-lara, f., benitez, e., soto, j., hervas, d. & polo, a. (1997): metal extractability and availability in a soil after heavy application of either nickel or lead in different forms.– water, air, and soil pollution, 94, 33–44. novozamsky, i., lexmon, t.m. & houba, v.j.g. (1993): a single extraction procedure of soil for evaluation of uptake of some metals by plants.– international journal of analytical chemistry, 51, 47–58. olayinka, k.o., oyeyiola, a.o., odujebe, f.o. & oboh, b. (2011): uptake of potentially toxic metals by vegetable plants grown on contaminated soil and their potential bioavailability using sequential extraction.– journal of soil science and environmental management, 2/8, 220–227. oreščanin, v., katunar, a., kutle, a. & valković, v. (2003): heavy metals in soil, grape, and wine.– j. trace microprobe t., 21, 171–180. doi: 10.1081/tma-120017912. pertsemli, e. & voutsa d. (2007): distribution of heavy metals in lakes doirani and kerkini, northern greece.– journal of hazardous materials, 148/3, 529–537. perin. g., craboledda. l., lucchese, m., cirillo, r., dotta, l., zanette, ml. & orio, a.a. (1985): heavy metal speciation in the sediments of northern adriatic sea. a new approach for environmental toxicity determination.– heavy metal in the environment, 2, 454–456. pekeč, s., vrbek, b., orlović, s. & ballian, d. (2013) water dynamics and physical characteristics of hydromorphic soils in southern bačka.– periodicum biologorum, 115/3. piper, c.s. (1931): the availability of manganese in the soil.– the journal of agricultural science, 21, 762–779. prica, m. (2011): correlation between different approaches for metal availability assessment.– romanian journal of aquatic ecology 1.1., 1–18. pueyo, m., mateu, j., rigol, a., vidal, m., lo´pez-sa´nchez, j.f. & rauret g. (2008): use of the modified bcr three-step sequential extraction procedure for the study of trace element dynamics in contaminated soils.– environmental pollution, 152, 330–341. ramirez, m., massolo, s., fraiche, r. & correa, j. (2005): metal speciation and environmental impact on sandy beaches due to el salvador coppermine, chile.– marine pollution bull, 50, 62–71. resulović, h. (1997): pedologija sa geologijom.– federacija bih ministarstvo obrazovanja, nauke, kulture i sporta. sarajevo-publishing, sarajevo. resulovic, h. & čustović, h. (2002): pedologija.– univerzitet u sarajevu. rouhollah, k. & farzaneh, s. (2010): determination of trace levels of nickel and manganese in soil, vegetable, and water.– clean soil, air, water, 38, 177–1183. robbins, j.m., lyle, m., heath, g.r. (1984): a sequential extraction procedure for partitioning elements among co-existing phases in marine sediments.– college of oceanography, oregon state university, 84–3, 64. rutten, a. & gert, j. (2003): sequential extraction of iron, manganese and related elements in s1 sapropel sediments, eastern mediterranean.– palaeogeography, palaeoclimatology, palaeoecology, 190, 79–101. saletovic, m., hodzic, z., banjanin, b. & kesic, a. (2011): bioavailability of microelements (cu, zn, mn) in medicinal plants.– healthmed, 5/5, 1358–1364. sahuquillo, a., rigol, a. & rauret, g. (2003): overview of the use of leaching/extraction tests for risk assessment of trace metals in contaminated soils and sediments.– trends in analytical chemistry, 22, 152–159. schwertmann, u. (1991): solubility and dissolution of iron oxides.– plant soil, 130, 1–25. silveira, m.l., alleoni, l.r.f., o’connor, g.a. & chang, a.c. (2006): heavy metal sequential extraction methods – a modification for tropical soils.– chemosphere, 64, 1929–1938. sutherland, r.a., tack, f.m.g., tolosa, c.a. & verloo, m.g. (2000): operationallydefined metal fractions in road deposited sediment, honolulu, hawaii.– j. environ. qual., 29, 1431–1439. tessier, a. & campbell, p.g.c. (1987): partitioning of trace metals in sediments: relationship with bioavailability.– hydrobiologia, 149, 43–52. tessier, a., campbell, p.g.c. & bison, m. (1979): sequential extraction procedure for the speciation of particulate trace metals.– analitica chemica, 5, 844–851. trudinger, p.a. & swaine, d.j. (1979): biogeochemical cycline of mineral – forming elements.– elsevier scientific publ., 253 p. vukadinović, v. & lončarić, z. (1998): ishrana bilja, poljoprivredni fakultet u osijeku, osijek. warren, r.s. & birch, p. (1987): heavy metal levels in atmospheric particles, roadside dust and soil along a major urban highway.– sci. total. environ., 59, 253–256. doi: 10.1016/0048-9697(87) 90446-3. geologia croatica 67/1geologia croatica 58 wuana, r.a., okieimen, f.e. & imborvungu, j.a. (2010): removal of heavy metals from a contaminated soil using organic chelating acids.– int. j. environ. sci. tech., 7/3, 485–496. zakir, h.m. & shikazaono, n. (2011): environmental mobility and geochemical partitioning of fe, mn, co, ni and mo in sediments of an urban river.– journal of environmental chemistry and ecotoxicology, 3/5, 116–126. zemberyova, m., bartekova, j. & hagarova, i. (2006): the utilization of modified bcr three-step sequential extraction procedure for the fractionation of cd, cr, cu, ni, pb and zn in soil reference materials of different origins.– talanta, 70, 973–978. zhang, y., cai, y., wang, c. & xue, g. (2012): characters and influencing factors of the distribution of cultivated available soil fe, mn, cu and zn in xichang city, sichuan province, china.– journal of geography and geology, 4, 2. zoumis, t., schimdt, a., grigorova, l. & calmano, w. (2001): contaminants in sediments: remobilisation and demobilisation.– the science of the total environment, 266, 195–202. manuscript received august 12, 2012 revised manuscript accepted february 18, 2014 available online march 21, 2014 . 05_bermanec.indd 67 � ab stra ct phosphate minerals hydroxylapatite, fl uorapatite and crandallite were identifi ed in nodules within phosphorites from ervenik, croatia. the minerals were identifi ed using optical microscopy, xrd, sem and eds analyses. the presence of fungi was recognized only in association with phosphate-rich phases. fungal activity resulted in the dissolution of apatite, producing hollow crystals, particularly in hydroxylapatite–enriched zones. a substantial number of hyphae were observed on the surface of phosphate minerals, in addition to saprophytic bacteria and bacterial spores. induced activity of phosphate-accumulating bacteria in an aquatic environment caused dissolution of the phosphate minerals. the aqueous phase contained increased concentrations of several elements, including ca, sb, u, v and as. these elements are important constituents of minerals of the apatite group. as a consequence of the crystallization of apatite, the concentration of phosphate decreases with a corresponding increase in aluminium concentration, resulting in the prevalence of crandallite as the stable phase, forming the outer sector of the spherulites. keywords: phosphorite, hydroxylapatite, fl uorapatite, crandallite, fungi, bacteria mineralogical and geomicrobiological investigation of phosphorite from ervenik, croatia � vladimir bermanec1, hrvoje posilović2, željka žigovečki gobac1, jasna hrenović3, nevenka mikac4 and goran kniewald4 1 institute of mineralogy and petrography, department of geology, faculty of science, university of zagreb, horvatovac 95, 10000 zagreb, croatia 2 croatian geological survey, sachsova 2, 10000 zagreb, croatia 3 department of microbiology, division of biology, faculty of science, university of zagreb, rooseveltov trg 6, 10000 zagreb, croatia 4 division for marine and environmental research, rudjer bošković institute, bijenička 54, 10000 zagreb, croatia doi: 104154/gc.2012.05 geologia croatica 65/1 67–75 8 figs. 3 tabs. zagreb 2012 geologia croaticageologia croatica 1. introduction phosphorite deposits commonly occur in caves, caverns and other karst phenomena (dahanayake & subasinghe, 1989; and references therein). they were identifi ed in limestones near the village of ervenik, in croatia during a 2009 fi eld campaign. it is generally assumed (ivanović et al., 1973) that these limestones are of cretaceous age, while the exact age of the deposits is unknown, but assumed to be pleistocene. the source of phosphorus could be the phosphate-rich guano material originating from bats and birds inhabiting the surrounding caves (marković, 2002). several outcrops of these deposits were found at the foot of the se part of mt. velebit near ervenik, croatia (posilović et al., 2010). phosphates are considered distinct in that they are able to incorporate more than half of the elements of the periodic table into their atomic structures (pasero et al., 2010). the apatite group minerals and crandallite are assumed to be secondary alteration phases and the main phosphorus-bearing minerals. the aim of this study was to defi ne the paragenesis of phosphorite from ervenik, croatia and to study bacteriological infl uence to this phosphorite. geologia croatica 65/1geologia croatica 68 2. materials and methods 2.1. sampling and preparation of minerals phosphorite samples were collected at a location close to the village of ervenik (fig. 1). the former phosphorite mine is no longer operational, so the samples were collected from old mine dumps. thin sections were prepared for optical investigation. the collected rock samples were crushed, sieved and the particle size of 0.212–0.500 mm was prepared in the laboratory for separation and bacteriological experiments, as well as other analyses. 2.2. experimental methods a polarising microscope was used for optical investigations. mineral phase determinations of the bulk samples were done using a philips x’pert powder diffractometer, with cukα radiation fi ltered with a graphite monocrystal monochromator running at 40 kv and 40 ma. an x-ray diffraction data set was collected from 4 to 65º2θ. powder diffraction patterns were identifi ed and indexed using x’pert highscore plus v. 2.1. software (panalytical, 2004), and icdd powder diffraction fi le database (pdf 2, iccd, 2004). unit cell parameters were calculated using “unitcell“ software (holland & redfern, 1997). crushed samples of phosphorite were examined by scanning electron microscopy (tescan vega ts 5136), coupled with an inca 250 system for elemental composition analysis. the water content in the minerals was determined by drying a 1.000 g aliquot of the mineral at 105°c/4 h. in sieved samples, the number of natively present bacteria was established. since the mineral samples were originally found under aerobic conditions and were maintained in an appropriate environment until analysis, the number of aerobic/facultatively anaerobic bacteria was checked. the number of natively present heterotrophic bacteria either viable or in the form of spores was determined in each mineral. the presence of faecal streptococci was tested in order to check the possible anthropogenic infl uence in the form of faecal contamination in the minerals (bouvy et al., 2010). in order to check whether the minerals facilitated bacterial growth in contact with water, bacteriological tests were performed (1) after 3 min, and (2) after 4 days of incubation. in order to check if the phosphate-accumulating bacteria use the minerals as the source of phosphorus, the performance of phosphate-accumulating bacteria acinetobacter junii dsm no. 1532 was tested (hrenović et al., 2010a). for determination of the presence of bacteria in minerals, a 1.0 g aliquot of each mineral was placed in a tube containing 9 ml of 0.05 moll–1 nacl. samples were vigorously shaken on a mechanical shaker (45hz/3min, kartell tk3s) in order to detach the adsorbed bacteria from the mineral (durham et al., 1994). the number of aerobic/facultatively anaerobic bacteria was determined in the supernatant. the number of faecal streptococci was determined on slanetz-bartley agar (biolife, italy) after 3-day incubation at 37°c. the number of heterotrophic bacteria and bacterial spores was determined on the nutrient agar (biolife, italy) after 3-day incubation at 22 °c. in order to determine the number of bacterial spores, the minerals were pasteurized at 80 °c for 10 minutes. figure 1: location map and geological setting of phosphorite occurrence near ervenik, croatia. basic lithologies are simplifi ed after ivanović et al. (1973). bermanec et al.: mineralogical and geomicrobiological investigation of phosphorite from ervenik, croatia geologia croatica 69 in order to establish the likelihood of multiplication of the bacteria present on mineral surfaces in contact with water, a 1.0 g aliquot of each mineral was placed in a tube which contained 9 ml of 0.05 moll–1 nacl and incubated for 4 days in the dark at 22 °c, with continual stirring (70 rpm) without additional aeration. the bacteriological analysis was performed after this incubation period. in order to check if the phosphate-accumulating bacteria a. junii use the minerals as a source of phosphate, a 1.0 g of autoclaved (121°c/20 min) mineral was placed in a tube which contained 9 ml of 0.05 moll–1 nacl. a suspension of a. junii was added (1.06±0.04 x 107 cfu/ml) to each tube and these were aerobically incubated in darkness for 24 h at 30°c with stirring (70 rpm). after incubation, samples were vigorously shaken on a mechanical shaker in order to detach the adsorbed bacteria from the mineral. the number of a. junii was determined from the supernatant on the nutrient agar after incubation at 30 °c/24 h. the neisser stain was utilised to confi rm the presence of polyphosphate granules in the cells of a. junii while the gram stain was used to confi rm the shape of bacteria and immobilization of the cells on the mineral surfaces. all measurements were done in triplicate. the fi nal ph of the suspension was measured using a wtw 330 ph-meter. a multi-element analysis of water samples after the dissolution experiments was done by high resolution inductively coupled plasma mass spectrometry (hr-icpms), on the sector-fi eld instrument element 2 (thermo, bremen, germany). the samples were diluted and an indium internal standard (1 µl–1) added. the measurements of selected isotopes were performed at three different resolutions: low resolution (7li, 85rb, 98mo, 111cd, 120sn, 121sb, 133cs, 205tl, 208pb,238u), medium resolution (23na, 25mg, 27al, 42ca, 51v, 52cr, 59co, 55mn, 56fe, 59co, 60ni, 63cu, 66zn, 86sr, 138ba) and high resolution (39k, 75as). external calibration was used for quantifi cation. standards were prepared by appropriate dilution of a multi-element reference standard (analytika, czech republic). details of the analytical method are described elsewhere (fiket et al., 2007). statistical analyses were carried out using statistica software 9.1 (statsoft, 2009). the numbers of bacterial cfu were logarithmically transformed beforehand to normalize the distribution and to equalize variances of the measured parameters. the comparisons between samples were done using the one-way analysis of variance (anova), and subsequently the post-hoc duncan test was performed for calculations concerning pair-wise comparisons. statistical decisions were made at a signifi cance level of p<0.05. 3. results 3. 1. mineralogical analyses the phosphate mineral occurrences found in caves are usually compact and reddish or greyish in colour, with a high al2o3 and feo content, but low in carbonate. the minerals occur as white to greyish spherulitic aggregates or single crystals <2 mm in size. optical microscopy and sem of spherulitic aggregates showed at least two different phosphate phases. thin sections of phosphate containing samples show clear zonality. in the inner core of the spherulites, apatite crystallises in the form of crystal sprays up to 1.5 mm in length; the outer parts of the spherulites contain very fi nely grained radial to fi brous crandallite. larger spherulites are banded and composed of alternating apatite and crandallite layers. samples of phosphorite recently collected at the mine dumps, left during the 1950’s were crushed to grains, up to 2mm diameter and separated into three fractions named: ervenik_white, ervenik_pink and ervenik_mix. on the basis of combined sem, eds and xrd analyses, the phosphate phases were identifi ed as hydroxylapatite, fl uorapatite, and crandallite. the sample ervenik_white has been identifi ed as an apatite group mineral (predominantly fl uorapatite), based on these unit cell parameters: p63/m, a = 9.423(2) å, c = 6.878(2) å, and v = 529.0(2) å3) (fig. 2a, table 1). in the sample ervenik_pink, two different phosphate phases were identifi ed: an apatite group mineral (predominantly hydroxylapatite) based on unit cell parameters: p63/m, a = 9.342(2) å, c = 6.893(2) å, and v = 520.9(2) å3) and crandallite (r3m, a = 7.006(3) å, c = 16.19(1) å, and v = 688.2(6) å3) (fig. 2c, table 1). as expected, in the sample ervenik_mix, a mixture of the aforementioned samples was identifi ed (fig. 2b, table 1). a very good fi t of the observed unit cell parameters with database information, enabled us to identify the mineral phases without additional chemical characterization. broken samples of phosphorite were used for sem investigations. idiomorphic apatite crystals were found in the cores of the nodules. the crystal habit is a simple combination of hexagonal prisms and basal faces. they are <50 µm long and <35 µm wide (usually 25 x 10 µm). some crystals show parallel growth, while others have more irregular growth patterns (fig. 3). some crystals are hollow. the smaller ones have empty cores, but larger crystals have a hexagonal core within the hollow outer part of the crystal. tiny fi bres connecting the core and crust of the crystals can occasionally be seen (fig. 3a). a closer look at the fi bres identifi ed them as fungal hyphae that grow on the surface of apatite crystals and infl uence these with their metabolic processes (fig. 4). the outer zones of nodules consist of smaller crystals of crandallite. crandallite crystals are of rhombohedral habit <5 µm in size. they usually have small basal faces (fig. 5), and are mutually separated by fi ne-grained anhedral bauxitic material. compositions of apatite and crandallite were confi rmed by eds analyses. eds analyses of apatite, in the cores of nodules, commonly show the presence of ca, p, and o. this is a strong indication for hydroxylapatite (fig. 6a). in contrast to hydroxylapatite, the eds spectrum of crandallite shows the additional presence of aluminium (fig. 6b). geologia croatica 65/1geologia croatica 70 figure 2: x-ray diff raction patterns of samples from ervenik. (a) sample ervenik_white; (b) ervenik_mix; (c) ervenik_pink; ap-1 = apatite group mineral (probably fl uorapatite); ap-2 = apatite group mineral (probably hydroxylapatite); cra = crandallite. bermanec et al.: mineralogical and geomicrobiological investigation of phosphorite from ervenik, croatia geologia croatica 71 3.2. bacteriological analyses the absence of faecal streptococci (bacteria of the genus enterococcus), used as surrogates for human and animal pathogens in assessing water quality (bouvy et al., 2010), confi rm ed that the minerals were not contaminated with mu ni cipal wastewater (table 2). the original minerals contained higher numbers of viable saprophytic bacteria than the bacterial spores (table 2). table 1: unit cell parameters for the identifi ed phases. mineral s.g. a / å c / å α γ v / å3 apatite group mineral ervenik_white p63/m 9.423(2) 6.878(2) 90.00° 120.00° 529.0(2) pdf 01-070-0796 (fl uorapatite) p63/m 9.4215 6.8739 90.00° 120.00° 528.41 apatite group mineral ervenik_pink p63/m 9.342(2) 6.893(2) 90.00° 120.00° 520.9(2) pdf 01-086-0740 (hydroxylapatite) p63/m 9.3520 6.8820 90.00° 120.00° 521.26 crandallite r3m 7.006(3) 16.19(1) 90.00° 120.00° 688.2(6) pdf 01-070-2069 (crandallite) r3m 7.0050 16.1920 90.00° 120.00° 688.09 figure 3: (a), (b) sem bse photograph of phosphorite from ervenik, croatia. apatite crystals (ap) are <50 µm long. most of them are hollow with central zone preserved. figure 4: the partial dissolution of an apatite crystal is a result of fungal activity on zonal apatite crystals (solid solution of hydroxylapatite and fl uorapatite). se mode allows better view of the organic hyphal tissue (h). figure 5: crandallite crystals (cra) from phosphorite are developed on the contact with the bauxitic host rock. the crystals are of rhombohedral habit and up to 5 µm in size. sem bse image. geologia croatica 65/1geologia croatica 72 the presence of viable bacteria in the materials may be explained by the 0.92–0.98% water content (which was lost at 105 °c/4 h) in the minerals, which was suffi cient to maintain the bacteria. the sample ervenik_pink naturally contained a signifi cantly lower number of viable saprophytic bacteria than the other two samples. after 4 days of incubation, the number of viable saprophytic bacteria signifi cantly increased in samples ervenik_white and ervenik_mix, but not in sample ervenik_pink. the sample ervenik_pink still contained the lowest number of viable saprophytic bacteria. the multiplication of saprophytes in samples decreased in order ervenik_white = ervenik_mix > ervenik_pink (table 2). it seems that the number of viable saprophytic bacteria and its multiplication was dependent of the content of crandallite in the minerals. in particular, the al contained in crandallite can have a negative infl uence and a toxic effect against bacteria (hrenović et al., 2010b). the number of bacterial spores (table 2) in the samples did not change on incubation of minerals in 0.05 mol l–1 nacl for 4 days. this suggested that the minerals in the presence of nutrient depleted water were not suitable for induction of the germination of bacterial spores. the fi nal ph values (table 2) of the aqueous media became alkaline after 3 min of contact of minerals with 0.05 mol l–1 nacl, and slightly decreased to neutral after 4 days of incubation. although signifi cantly higher in the aqueous medium which contained the sample ervenik_pink than ervenik_ white or ervenik_mix, the maximum difference was only 0.19 ph units. therefore, the ph value of the medium can be eliminated as a cause of different bacterial numbers in minerals. in experiments with phosphate-accumulating bacteria, all inoculated bacteria a. junii were immobilized onto minerals during 24 h of incubation (fig. 7). the number of immobilized bacteria per mass of dry mineral was 1.04±0.09 x 107 cfu/g. there was no signifi cant change among the initial and fi nal numbers of a. junii in the tubes. it is probable, that the mineral and nutrient depleted water failed to provide enough sources of nutrients for multiplication of bacteria which were isolated from activated sludge treating the wastewater (hrenović et al., 2003). all inoculated bacteria survived and accumulated polyphosphate inside the bacterial cells. the phosphate accumulated inside the cells of a. junii in the form of polyphosphate granule was confi rmed by the neisser stain (fig. 8). this experiment confi rmed that the phosphate-accumulating bacteria a. junii were able to use the minerals as the source of phosphate for their metabolism. these fi ndings are in agreement with smith et al. (1978), where suffi cient phosphate was released by the partial dissolution of apatite crystals at ph 7.8 to support the growth of bacteria. the fact that all inoculated bacteria survived and were spontaneously immobilized onto minerals confi rmed that the investigated phosphorites were excellent substrates for the immobilization of selected bacteria. figure 6: (a) eds spectrum of hydroxylapatite. (b) eds spectrum of crandallite. table 2: number of bacteria per 1.0 g of dry mineral after 3 min and after 4 days of contact with water. * signifi cantly diff erent at 4 days when compared to 3 min; a signifi cantly diff erent to ervenik_white; b signifi cantly diff erent to ervenik_mix. parameter ervenik_white ervenik_mix ervenik_pink 3 min saprophytic bacteria (103 cfu/g) 5.17±1.04 6.70±0.95 2.37±1.12a,b bacterial spores (cfu/g) 55±15 72±12 45±15 faecal streptococci (cfu/g) 0 0 0 final ph 7.74±0.02 7.76±0.02 7.81±0.02 a,b 4 days saprophytic bacteria (103 cfu/g) 42.33±9.45* 52.33±9.07* 2.43±0.87a,b bacterial spores (cfu/g) 61±7 78±9 a 43±8 a,b faecal streptococci (cfu/g) 0 0 0 final ph 7.47±0.02* 7.47±0.02* 7.66±0.02 *,a,b multiplication of saprophytes (c4days/c3min) 8.2±1.0 7.8±0.3 1.0±0.1 a,b bermanec et al.: mineralogical and geomicrobiological investigation of phosphorite from ervenik, croatia geologia croatica 73 after the contact of the sample ervenik_white with a. junii, the solution was fi ltered through a sartorius nitrocellulose fi lter with a pore diameter of 0.2 μm and the water was analysed by icp-ms to compare it with a blank solution of 0.05m nacl, in order to detect the bacteriological activity on the phosphate minerals (table 3). a set of 22 trace elements were measured: al, as, ba, cd, co, cr, cs, cu, fe, li, mn, mo, ni, pb, rb, sb, sn, sr, tl, u, v, and zn, (most of these elements are common constituents of apatite group minerals), as well as the macroelements ca, k, mg and na which were expected at higher concentrations. na was measured in both blanks and in sample waters in the same order of concentrations. the concentrations of ca, mg and k in the aqueous phase of the samples were higher after bacteriological activity. the highest increase in concentration was observed for ca (124-fold) when compared to concentrations of mg and k (5 and 14 times, respectively). this observation is in agreement whit the statement that mg and k ions were essential elements for a. junii while ca was not (hrenović et al., 2010c). additionally, ca is the dominant cation in apatite and mg and k are minor constituents. among the trace elements, the bacterial activity has the highest infl uence on the concentrations of sb, u, v and as, which increased 973, 105, 452 and 226 times, respectively. a signifi cant increase in the concentrations was also established for ni, cu and sr (24, 61 and 57 times, respectively). li, cd, cr, mn and co increased their concentrations about 10 times, rb, mo, tl, and al increased about 5 times, sn, fe and ba about 2 times, pb concentration remained the same, while cs concentration signifi cantly decreased. it is possible that a. junii has the ability to accumulate cs within its cells or on their surface, which has been observed for other bacteria (nakao et al., 2005), but this needs to be further examined. increased concentrations of elements may be explained as a result of the dissolution of hydroxylapatite, which can contain these elements in its crystal lattice. these elements are not involved in bacterial metabolic processes. figure 7: cells of a. junii immobilized onto mineral ervenik_white. figure 8: granules of polyphosphate inside the cells of a. junii immobilized onto mineral ervenik_white. table 3: concentrations of macro and trace elements in water after dissolution experiments in the presence (sample) and absence (blank) of a. junii bacteria. macroelements concentration (mg l–1) probe blank ca 62.00 0.50 k 14.10 1.00 mg 0.90 0.20 na 1294 1280 trace elements concentration (µg l–1) probe blank al 8.40 1.87 as 2.26 0.01 ba 17.3 11.2 cd 0.16 0.01 co 0.29 0.03 cr 7.53 0.94 cs 0.02 0.13 cu 40.16 0.66 fe 0.98 0.46 li 1.97 0.17 mn 3.34 0.20 mo 0.65 0.14 ni 3.14 0.13 pb 0.09 0.11 rb 1.93 0.34 sb 9.73 <0.01 sn 0.09 0.06 sr 70.71 1.23 tl 0.04 0.01 u 1.05 0.01 v 9.04 0.02 zn 128.8 91.4 geologia croatica 65/1geologia croatica 74 4. discussion and conclusion from the results of the x-ray diffraction analysis it is possible to identify that the minerals investigated (according to their structure) belong to the apatite group of minerals (hexagonal apatites). apatite group minerals consist of 15 different minerals. most of them (11) have the same hexagonal structure and the space group p63/m (pasero et al., 2010). by calculating unit cell parameters, it is possible to conclude that these are apatite group minerals (ca5(po4)3x, x=f, oh, cl), having unit cell parameters comparable to fl uorapatite and hydroxylapatite. unit cell dimensions of apatite group minerals in the separated parts of spherulites signifi cantly differ from each other, suggesting that there are two end members present in these nodules, partly making solid solutions. the most interesting members of the apatite group are hydroxylapatite and fl uorapatite, as they can be affected by biological activity. the plumbogummite subgroup of the alunite-jarosite group of minerals (back & mandarino, 2008) contains phosphates that are very important as weathering products, commonly present as constituents of soils. according to unit cell calculations and eds measurements, this is crandallite caal3(po4)2(oh, h2o)6. this mineral phase is related to the presence of aluminium in bauxitic material surrounding the spherulites. the identifi ed phosphate minerals are assumed to be associated with biomineralization processes, these being a consequence of organic matter interaction with the carbonate phases of the host rock limestones (posilović et al., 2010). careful investigation of the collected samples prior to bacteriological/biological experiments, resulted in the interesting observation that fungi only grow on phosphate rich sections of the mineral substrate, and not on carbonate nor iron and aluminium rich oxide phases. due to the higher solubility of hydroxylapatite, with respect to fl uorapatite, hydroxylapatite enriched zones were preferentially dissolved resulting in hollow apatite crystals. crandallite formation on the contact of phosphorite nodul es with the surrounding bauxite matrix is the result of increased aluminium availability. apatite and crandallite spheru lit es were formed during early diagenesis of the cave sediment; each single spherulite was precipitated in a partially closed microenvironment of the sediment voids and pores. apatite occupying the central portions of the spherulite centre, formed prior to crandallite in the outer spherulite region. the calculated stability fi elds for apatite and crandallite may be used to explain the bi-phase precipitation in the spherulites. higher phosphate and lower aluminium concentrations with higher ph will favour apatite precipitation; such conditions prevailed during precipitation of the spherulite core. as a consequence of apatite precipitation, phosphate concentration is decreased and aluminium is increased, the stability fi eld of crandallite prevails and crandallite becomes the stable phase precipitating in the spherulite outer sectors (posilović et al., 2010). acknowledgement this research was supported by the ministry of science, education and sports of the republic of croatia (project nos. 119-0000000-1158, 119-1191155-1203, and 098-09829342715). references back, m.e. & mandarino, j.a. (2008): fleischer’s glossary of mineral species 2008.– the mineralogical record inc., tucson, 345 p. bouvy, m., arfi, r., bernard, c., carre, c., got, p., pagano, m. & troussellier, m. (2010): estuarine microbial community characteristics as indicators of human-induced changes (senegal river, west africa).– estuar. coast. shelf s., 87, 573–582. doi: 10.1016/j.ecss.2010.02.015 dahanayake, k. & subasinghe, s.m.n.d. (1989): secondary phosphate mineralization in a karstic environment in central sri lanka.– min. dep., 24/3, 169–175. doi: 10.1007/bf00206439 durham, d.r., marshall, l.c., miller, j.g. & chmurny, a.b. (1994): characterization of inorganic biocarriers that moderate system upsets during fi xed-fi lm biotreatment process.– appl. environ. microbiol., 60, 3329–3335. fiket, ž., roje, v., mikac, n. & kniewald, g. (2007): determination of arsenic and other trace elements in bottled waters by high resolution inductively coupled plasma mass spectrometry.– croat. chem. acta, 80, 91–100. holland, t.j.b. & redfern s.a.t. (1997): unit cell refi nement from powder diffraction data: the use of regression diagnostics.– mineral. mag., 61, 65–77. hrenović, j., tibljaš, d., buyukgungor, h. & orhan, y. (2003): infl uence of support materials on phosphate removal by the pure culture of acinetobacter calcoaceticus.– food technol. biotechnol., 41, 331–338. hrenović, j., ivanković, t., tibljaš, d., kovačević, d. & sekovanić, l. (2010a): sepiolite as carrier of the phosphateaccumulating bacteria acinetobacter junii.– appl. clay sci., 50, 582–587. doi:10.1016/j.clay.2010.10.024 hrenović, j., željezić, d., kopjar, n., sarpola, a., bronić, j. & sekovanić, l. (2010b): antimicrobial activity of commercial zeolite a on acinetobacter junii and saccharomyces cerevisiae.– j. hazard. mater., 183, 655–663. doi: 10.1016/j.jhazmat. 2010.07.076 hrenović, j., ivanković, t. & rožić, m. (2010c): requirement of acinetobacter junii for magnesium, calcium and potassium ions.– journal of bioscience and bioengineering, 110, 180–186. doi: 10.1016/j.jbiosc.2010.02.011 ivanović, a., sakač, k., marković, s., sokač, b., šušnjar, m., nikler, l. & šušnjara, a. (1973): osnovna geološka karta sfrj 1:100000, list obrovac l33-140 [basic geological map of sfrj 1:100000, obrovac sheet – in croatian].– institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd. marković, s. (2002): hrvatske mineralne sirovine (mineral deposits of croatia).– institut za geološka istraživanja, zagreb, 544 p. nakao, a., yoshida, t., ozaki, t., ohnuki, t., funakawa s., kosaki, t. (2005): cs accumulation behaviour by pseudomonas fl uorescens. journal of nuclear and radiochemical sciences, 6, 107–110. panalytical (2004): x’pert highscore plus v. 2.1, panalytical b. v., almelo. bermanec et al.: mineralogical and geomicrobiological investigation of phosphorite from ervenik, croatia geologia croatica 75 pasero, m., kampf, a.r., ferraris, c., petkov, i.v., rakovan, j. & white, t.j. (2010): nomenclature of the apatite supergroup minerals. eur. j. mineral., 22, 163–179. doi: 10.1127/09351221/2010/0022-2022 posilović, h., kniewald, g., žigovečki gobac, ž. & bermanec, v. (2010): physico-chemical constraints of apatite and crandallite formation in phosphorites from ervenik, croatia.– in: zaharia, l., kis, a., topa, b., papp, g. & weiszburg, t.g. (eds.): acta mineralogica-petrographica, abstract series, vol. 6, ima2010, department of mineralogy, geochemistry and petrology, university of szeged, szeged, hungary, 16 p. powder diffraction file (2004): database sets 1–54.– international centre for diffraction data (icdd), newtown square. smith, e.a., mayfield, c.i. & wong, p.t.s. (1978): naturally occurring apatite as a source of orthophosphate for growth of bacteria and algae.– microb. ecol., 4, 105–117. doi: 10.1007bf02014281 statsoft (2009): statistica v. 9.1, statsoft, inc. tulsa manuscript received june 27, 2011 revised manuscript accepted october 07, 2011 available online february 25, 2012 geologia croatica 65/1geologia croatica 76 ab stra ct the results of the fi rst systematic study of the spatial distribution of trace metals in surface soil over the kičevo region, republic of macedonia, known for its coal mine and thermal power plant activity are reported. the investigated region (148 km2) is covered by a sparse sampling grid of 2×2 km; but in the urban zone and around the thermal power plant the sampling grid is denser (1×1 km). in total, 52 topsoil samples (0–5 cm) were collected. inductively coupled plasma – atomic emission spectrometry (icp-aes) was applied for the determinations of 18 elements (al, as, ba, ca, cd, co, cr, cu, fe, k, li, mg, mn, na, ni, pb, sr and zn). based on the results of factor analyses, three natural geogenic associations of elements have been defi ned: f1: cr-ni-li-co-fe-as; f2: al-ca-mg-sr; and f3: ba-k-cu. even the distributions of typical heavy metals such as pb and zn which are not isolated into anthropogenic geochemical association by multivariate statistical methods still show some trends of local anthropogenic enrichment. first of all, the distribution of pb is not only infl uenced by the open coal pit and“„oslomej” thermal power plant, but also by river transportation processes from the“„tajmište” iron mine into alluvial sediments of the river zajaska. the distribution of zn is infl uenced by the“„metal industry kičevo” operation and atmospheric transport. keywords: multivariate statistics, potentially toxic elements, geochemical mapping, soil, kičevo  geochemical properties of topsoil around the open coal mine and oslomej thermoelectric power plant, r. macedonia  trajče stafi lov1, robert šajn2, florije sulejmani1 and katerina bačeva1 1 institute of chemistry, faculty of natural sciences and mathematics, skopje, republic of macedonia, pob 162, 1000 skopje, republic of macedonia; (trajcest@pmf.ukim.mk) 2 geological survey of slovenia, dimičeva ulica 14, 1000 ljubljana, slovenia; (robert.sajn@geo-zs.si) doi: 10.4154.gc.2014.03 geologia croaticageologia croatica geologia croatica 67/1 33–44 5 figs. 4 tabs. zagreb 2014 soil and consequently their bioavailability differs depending on their origin. however, regardless of the forms of the anthropogenic elements in soil, their phytoavailability is signifi cantly higher than those of pedogenic origin. urban and regional contamination of soil occurs mainly in industrial regions and within centres of large settlements, where factories, motor vehicles and municipal wastes are the most important sources of trace metals (kabata-pendias & pendias, 2001; šajn, 2004; 2005; davidson et al., 2006). given the heterogeneity and ceaseless change in urban areas (chen et al. 2005), it is necessary fi rst to understand the natural distribution. however, there are cases when the industrial enterprises, especially mining and metallurgical plants, situated near cities can increase the pollution. it is obvious from the papers published recently that mining and metallurgical activities lead to enormous soil contamination 1. introduction the abundance of trace metals in soil has been increased dramatically by the accele rated rate of extraction of minerals and fossil fuels and by highly technological industrial processes. rapid increases of trace metal concentrations in the environment are commonly coupled to the development of exploitative technologies. the presence of heavy metals in soil could be in trace amounts. soils contain trace elements of various origins (kabata-pendias & pendias, 2001). lithogenic elements are directly inherited from the lithosphere. pedogenic elements are types of elements with a lithogenic origin, but their concentration and distribution in soil layers, as well as in soil particles are changed due to pedogenic processes. anthropogenic elements are all those deposited into soil as direct or indirect results of man’s activities. the behaviour of trace metals in geologia croatica 67/1geologia croatica 34 (wilson et al., 2005; pruvot et al., 2006; šajn et al., 2011), which is the case with some regions in the republic of macedonia (stafilov et al., 2008a, b; 2010a, b, c). the purpose of this study is to present the results of the first systematic research of multi elemental soil characterisation over the kičevo region, known for its coal mine and the“„oslomej” thermal power plant. studies on the atmospheric deposition of trace metals elements over the entire territory of the republic of macedonia identified the most polluted areas and characterized the different pollution sources (barandovski et al., 2008; balabanova et al., 2010, 2011; gjorgieva et al., 2010; 2011). it was found that the most important sources of trace metal deposition are ferrous and non-ferrous smelters including the emission from the thermal power plants using coal. for this reason, two specific purposes of the present study were (1) to determine the content of the following trace elements (al, as, ba, ca, cd, co, cr, cu, fe, k, li, mg, mn, na, ni, pb, sr and zn) in the soil, and (2) to assess the size of the affected area by the thermal power plant situated very close to the town. 2. study area kičevo is located in the western part of macedonia, in the south-eastern foothills of bistra mountain (fig. 1), at the mid point on the road between ohrid (61 km) and gostivar (46 km). it is 112 km from the capital skopje kičevo is surrounded by mountains and forests, and is a town that is attractive not only because of its natural beauty, but also because of its cultural values. according to the 2002 census, kičevo had a population of about 30.000 inhabitants (macedonians, albanians, turks, serbs and gypsies). the whole region, with the communities of kičevo, oslomej and zajas has about 52.000 people and comprises extraordinary patterns of social and economic diversity. kičevo is an important industrial centre in this part of macedonia, due to the iron mine in tajmište (abandoned at the moment), the coal mine and the „oslomej” thermal power plant. kičevo is a mining town that started to develop very intensively after world war ii. the main feature of the economy in the region is the mining and rek „oslome” thermal figure 1: location of the study area. stafilov et al.: geochemical properties of topsoil around the open coal mine and oslomej thermoelectric power plant, r. macedonia geologia croatica 35 power plant. it is the first facility of its kind built in the country. rek“„oslome”“ has the installation capacity of 125 mw with a net annual production of around 700 gwh. rek oslomej began production in 1980 and has had excellent production results. it provides about 9% of the total electrical energy production in the republic of macedonia. kičevo region is influenced by the warm continental and mountain climate. the zone of influence of the warm continental climate in macedonia is from 600 to 900 m a.s.l., meaning this climate area in the kičevo region includes the town of kičevo and most of the settlements. mountain areas are affected by the mountain climate. the annual average temperature in the immediate area of the city is 10.7оc with the absolute monthly maximum temperature of 40.5оc, while the absolute monthly minimum was –23оc. the mean annual maximum temperature is 17.1оc and an average annual minimum temperature is 5оc. the average annual rainfall is about 750 mm while the most frequent wind direction is n-s (lazarevski, 1993) the above climatic and other natural conditions in this region have a constraining influence on the cultivation of apples and pears, and favourable conditions for growing some of the stone fruit types (cherry, plum) but also for breeding walnut and chestnut. the study area is located in the western part of the republic of macedonia with a surface of ca. 12 km (w–e) × 16 km (s–n), (148 km2), between the coordinates n: 41°29’5”“–41°38’4”“ and e: 20°54’3”“–21°03’2”“ (figs. 1 and 2). the altitude varies between 570 and 1260 m. land use (fig. 2a) is as follows: the cultivable area covers 64 km2 (43 %), non-cultivable area (mainly forests) 68 km2 (46 %), settlements 9.9 km2 (6.7 %) and area of oslomej open pit and thermal power plant 6.1 km2 (4.3 %). 3. geology the geological description (fig. 2b) is according to petkovski & ivanovski (1973), and dumurdjanov et al. (1972). the study area is a part of the western macedonian zone, which belongs to the inner dinarides. the structure strikes in a nw-se direction. two types of orogeny strongly influenced the development of the zone. the hercynian (variscan) orogeny has influence on palaeozoic rocks which are regionally metamorphosed and fluted bu the alpine orogeny caused very strong metamorphism, intensive fluting and the conversion of older structures. subsequent radial tectonics have resulted in the formation of anticline structures and basins (the kičevo basin), that were filled by younger pliocene and quaternary sediments. the oldest rocks belong to the lower palaeozoic (pz) metamorphic complex, mostly consisting of phyllitoides with inclusion of metasandstone quartzite and carbonatic schist. the lower palaeozoic rocks are developed in the north of the study area. devonian (d) rocks overlie this complex. these are phyllitoides, sandstone and conglomerate, quartzite and marble. the devonian rocks outcrop in the southern part of the study area. over the palaeozoic beds, mesozoic rocks occur, represented by the jurassic diabase rocks (penetrations or inclusions of magmatic rocks), which outcrop on very limited part to the south. middle and upper pliocene sediments are developed in the central part of the study area (the kičevo basin) and consist of marl, sand and clay with coal layers, not exceeding 250 m in thickness. pliocene sediments were developed in the central part of the study area. alluvial sediments cover the flood plains along the rivers treska, zajaska and temnica that contain mainly coarse grained material such as gravel, sand and sandy clay. the study area covers 148 km2, but the quaternary deposits comprise 41.4 km2 (representing 28 % of the study area), pliocene marl, clay, sand and gravel account for 28.9 km2 (20%), jurassic diabase, 1.1 km2 (<1%), devonian marble represents 8.3 km2 (5.6%), devonian quartzite; 1.3 km2 (<1%), devonian phyllitoides; 15.7 km2 (11%), devonian sandstone and conglomerate cover 16.4 km2 (11%) and lower palaeozoic schists 34.9 km2 (23%). 4. materials and methods 4.1. sampling samples of natural surface soils in the town of kičеvo and the surrounding region were collected according to the european guidelines for soil pollution studies (reimann et al., 2008), and also according to our experience (stafilov et al., 2008 a, b; šajn, 2003, 2005, 2006). the study area (148 km2) is covered by a sampling grid of 2×2 km but in the urban zone of kičevo and around the oslomej thermal power plant the sampling grid is denser, 1×1 km. altogether 52 soil samples were collected (fig. 2c). at each sampling point, soil samples were collected as topsoil (0–5 cm). the possible organic horizon was excluded. one sample represents the composite material collected at the central sample point itself and at least four points within a radius of 10 m around it towards n, e, s and w. the mass of such a composite sample was about 1 kg (darnley et al., 1995). according to the basic lithological units, 10 sampling sites are located in the area of quaternary alluvium of the treska river, 14 in the quaternary alluvium of the zajaska and temnica rivers, 10 on pliocene marl, clay, sand and gravel, 3 from devonian sandstone and conglomerate, 4 on devonian marble, 6 on devonian phyllitoids and 10 on the lower palaeozoic schists (fig. 2c). 4.2. sample preparation and analysis the soil samples were air dried indoors at room temperature for about two weeks. then they were gently crushed, cleaned from extraneous material and sifted through a plastic sieve with 2 mm mesh (salminen et al., 2005). the sifted mass was quartered and milled in an agate mill to an analytical grain size below 0.125 mm. for digestion of soil samples, open wet digestion with a mixture of acids was applied. the digestion was carried out in this order: a precisely measured mass of dust samples (0.5 g) with the accuracy of 0.0001 g was placed in a teflon vessel. 5 ml of concentrated nitric acid (hno3) was added, until the brown vapours came out from the vessels. nitric acid is a very suitable oxidant for the digestion of organic geologia croatica 67/1geologia croatica 36 fi gu re 2 : a – l an d us e m ap ; b – l ith ol og ic al m ap ; c – l oc at io n of so il sa m pl in g si te s stafilov et al.: geochemical properties of topsoil around the open coal mine and oslomej thermoelectric power plant, r. macedonia geologia croatica 37 fi gu re 3 : s pa tia l d is tr ib ut io n of f ac to r s co re s: a – f ac to r 1 (c r, n i, li , c o, f e an d as ); b – fa ct or 2 (c a, s r, m g an d al ); c – fa ct or 3 (b a, k a nd c u) geologia croatica 67/1geologia croatica 38 matter in samples. for total digestion of the inorganic components 5–10 ml hydrofluoric acid (hf) was added. when the digest became a clear solution, 2 ml of hclo4 was added. perchloric acid was used for total digestion of organic matter. after cooling the vessels for 15 min, 2 ml of hcl and 5 ml of h2o were added for total dissolution of the metal ions. finally, the vessels were cooled and digests quantitatively transferred to 50 ml calibrated flasks (stafilov et al., 2008a; 2010c; balabanova et al., 2011). then the soil samples were analysed by atomic absorption (electrothermal – etaas, and flame – faas) and atomic emission spectrometry with inductively coupled plasma (icp-aes). optimization of the instrumental conditions for each element had been done previously (stafilov et al., 2010c; balabanova et al., 2011). total contents of 18 elements were analysed in the collected samples: al, as, ba, ca, cd, co, cr, cu, fe, k, li, mg, mn, na, ni, pb, sr and zn. the qc of the three applied techniques was performed by the standard addition method, and it was found that the recovery ranges for the investigated elements were: for fааs 97.2% – 102.5%, for eтaas 96.9% – 103.2%, for icp-aes 98.2% – 100.8%. 5. results and discussion 5.1. data processing all field observations, analytical data and measurements were introduced to the data matrix. for each observation there are 44 variables: sample identification number, sampling material type, geographic coordinates, type of analysis, land use, basic lithological units, level of soil pollution and determination of 18 analysed elements. parametric and nonparametric statistical tests were used for the data analysis (snedecor & cochran, 1967; davis, 1986). on the basis of the results, the normality tests and a visual inspection of the distribution histograms, the logarithms of the content were used for all elements, except as and k. differences between the defined groups of samples as well as their significance have been tested by t-test and f-test, respectively. the basic statistics for the 18 selected chemical elements and the averages of elements with regards to the basic lithological units in topsoil are shown in tables 1 and 2. the degree of association of chemical element content in the soil samples was assessed with the linear pearson’s r correlation coefficient (le maitre, 1982). it was qualitatively assumed that the absolute values of r between 0.5–0.7 reveal a good association, and between 0.7–1.0 a strong association between elements (table 3). arsenic and potassium show a normal distribution, but all other elements follow a logarithmic distribution. multivariate r-mode factor analysis (davis, 1986; borůvka, 2005) was used to reveal the associations of the chemical elements. factor analysis (fa or pca) derives from numerous variables a smaller number of new, synthetic variables called factors. the factors contain significant information about the original variables, and they may have certain meanings. factor analysis was performed on variables standardized to zero mean and unit of standard deviation (reimann, et al., 2002). as a measure of similarity between variables, the product-moment correlation coefficient (r) was applied. for orthogonal rotation, the varimax method was used. in the factor analysis, 52 samples of the topsoil (0–5 cm) and analysis of 13 chemical elements were considered. from the multivariate r-mode factor analysis, 5 chemical elements (cd, mn, na, pb and zn) were eliminated from further analysis because they have low share of communality or low tendency to form independent factors. using factor analysis, the distribution was reduced to three synthetic variables (f1 to f3), which showed linkage in terms of geochemical similarities. they include c. 74% of the total variability for all treated elements (table 4). the universal kriging with linear variogram interpolation method (davis, 1986) was applied for the construction of maps showing the spatial distribution of factor scores, as well as maps displaying the distribution of trace elements in topsoil. the basic grid cell size for interpolation is 20×20 m. for a graphical display of spatial distribution, the maps with percentile distribution have been used, where different colours represent different concentration arrangements. the seven classes of following percentile values were applied: 0–10, 10–25, 25–40, 40–60, 60–75, 75–90 and 90–100 (fig. 3 and 5). 5.2. natural associations of chemical elements in soils elements whose distributions reflect natural background levels have been released during weathering processes. their contents usually change gradually across the landscape and depend on the geological background. following the results of factor analysis (table 4) and the trends shown on the factor scores geochemical maps (fig. 3), three natural geochemical associations in soil have been identified. the most characteristic association comprises as, co, cr, fe, li and ni, which are assembled in the factor 1 (table 4, fig. 3a). the strongest factor explains 29 % of the total variability within the data of 13 selected chemical elements. all selected elements have a high correlation coefficient (table 3), as well as significant statistical differences among the determined groups of samples from the various lithological units (table 2). their sources are mainly natural phenomena, such as rock weathering and chemical processes in soil. in addition, the distribution of factor 1 scores (as, co, cr, fe, li and ni) in the topsoil is closely dependent on lithology (figs. 2c and 4a). their highest contents were found in areas of devonian sandstone and quaternary deposits of the treska river and their lowest values in the areas of the lower palaeozoic schists, pliocene sediments and quaternary deposits of the zajaska and temnica rivers. those chemical elements are mostly connected to the sandy fraction in soil. the association illustrated by factor 2 associates al, ca, mg and sr. the second strongest factor 2 contains high valstafilov et al.: geochemical properties of topsoil around the open coal mine and oslomej thermoelectric power plant, r. macedonia geologia croatica 39 table 1: descriptive statistics of measurements (n = 52). dis. x xg md min max s cv sx a e al log 1.7 1.5 1.4 0.53 4.7 0.92 54 0.13 0.22 –0.55 as n 9.3 6.3 7.8 0.13 34 7.2 77 1.0 1.25 1.60 ba log 390 380 380 160 890 120 31 17 -0.07 1.45 ca log 0.54 0.30 0.24 0.042 3.1 0.66 122 0.091 0.32 –0.67 cd log 0.47 0.42 0.42 0.17 0.99 0.21 44 0.029 –0.04 –0.74 co log 15 11 11 0.59 60 11 78 1.6 –0.71 2.14 cr log 44 41 43 13 110 17 38 2.4 –0.46 1.84 cu log 17 15 14 5.4 53 8.6 51 1.2 0.08 –0.04 fe log 2.9 2.8 2.8 1.5 5.4 0.66 23 0.092 0.11 0.94 k n 1.4 1.4 1.4 0.63 2.2 0.34 23 0.047 –0.09 0.27 li log 14 12 11 2.5 33 7.6 56 1.1 –0.29 –0.31 mg log 0.64 0.57 0.59 0.20 1.6 0.31 49 0.043 –0.01 –0.34 mn log 760 700 690 210 2600 370 48 51 0.11 1.74 na log 0.55 0.44 0.50 0.064 1.6 0.36 65 0.050 –0.48 –0.30 ni log 21 19 18 5.5 56 10 49 1.4 –0.17 0.40 pb log 96 64 71 1.7 430 80 84 11 –1.14 2.37 sr log 17 15 15 5.8 45 9.1 55 1.3 0.39 –0.11 zn log 150 110 97 11 1700 230 154 31 0.71 6.60 dis. – distribution (n – normal, log – lognormal); x – mean; xg – geometric mean; md – median; min – minimum; max – maximum; s – standard deviation; cv – coefficient of variation (%); sx – standard error of mean; a – skewness; e – kurtosis; values of al, ca, fe, k, mg and na are in %, remaining elements in mg/kg; values rounded at two digits table 2: averages of the chemical elements according to basic lithological units. eu study area sed t (q) sed z (q) sed (pl) sand (d) marblele (d)d) phyll (d) schist (pz) anova (f-test) n – 52 5 14 10 3 4 6 10 al 11 1.5 1.9 1.3 1.5 1.3 2.5 2.0 1.1 1.95 ns ca 0.92 0.30 0.52 0.32 0.27 0.14 1.2 0.26 0.18 2.42 * fe 3.5 2.8 3.4 2.7 2.9 3.5 2.9 3.5 2.3 4.62 * k 1.9 1.4 1.7 1.4 1.2 1.5 1.7 1.9 1.3 1.98 ns mg 0.77 0.57 1.0 0.57 0.50 0.46 0.75 0.59 0.48 0.71 ns na 0.8 0.44 0.64 0.74 0.35 0.25 0.35 0.17 0.49 3.49 * as 7 9.3 12 5.5 7.3 10 16 15 8.9 3.58 * ba 380 380 510 370 350 340 390 520 310 5.86 * cd 0.15 0.42 0.54 0.46 0.44 0.42 0.45 0.40 0.33 5.08 * co 7.8 11 21 8.9 7.8 19 13 9.6 13 4.98 * cr 60 41 61 38 40 49 47 55 31 8.11 * cu 13 15 21 14 12 15 26 23 10 1.86 ns li – 12 22 10 9.8 22 18 18 6.5 2.57 * mn 650 700 880 690 620 860 760 1000 510 3.50 * ni 18 19 34 18 17 21 27 26 12 6.46 * pb 23 64 50 57 110 56 91 46 60 0.72 ns sr 89 15 19 17 13 12 29 12 11 1.85 ns zn 52 110 160 120 87 120 200 120 65 0.56 ns (eu) – european topsoil average (salminen, 2005); sed t (q) – quaternary alluvium of the treska рiver (11.7 km2); sed z (q) – quaternary alluvium of the zajaska and temnica rivers (29.7 km2); sed (pl) – pliocene marl, clay, sand and gravel (28.9 km2); sand (d) – devonian sandstone and conglomerate (16.4 km2); marble (d) – devonian marble (8.3 km2); phyll (d) – devonian phyllitoids (15.7 km2); schist (pz) – lower palaeozoic schists (34.9 km2). values of al, ca, fe, k, mg and na are in %, remaining elements in mg/kg. values rounded at two digits. geologia croatica 67/1geologia croatica 40 ues of the aforementioned elements, explaining 26 % of the total variability (table 4, fig. 3b). there is a significant, high correlation coefficient (table 3) for this group of elements, but no significant statistical difference between the groups of samples from various lithological units (table 2). despite these, similarities to the distribution of the factor 1 scores, the spatial distribution of factor 2 scores (al, ca, mg and sr) in topsoil depends on the litholоgy. their highest contents were observed in areas of the devonian marble and quaternary deposits of the treska river and their lowest values, (as in factor 1), in the areas of the lower palaeozoic schists, pliocene sediments and quaternary deposits of the zajaska and temnica rivers (figs. 2c and 4b). the elements from this factor are connected to the carbonate minerals in soil, representing a product of marble weathering processes. the third naturally distributed geochemical association consists of ba, cu and k, chemical elements that are also little affected by anthropogenic activities. the factor 3 contains high values of the aforementioned elements, explaining 20% of the total variability within the data (table 4, fig. 3c). the elements from this group are showing lower correlation coefficients than the previous two, but still statistically significant (table 3). significant statistical differences between the defined groups of samples from isolated lithological units (table 2) are present. distribution of ba, cu and k in the topsoil also depends on the lithology (figs. 2c and 4c). their highest contents were discovered in areas of the devonian phyllitoides and their lowest values in the areas of the lower palaeozoic schists, pliocene sediments and quaternary deposits of the zajaska and temnica rivers, as for f1 and f2. these elements are connected to the clayey fractions. 5.3. distribution pattern of cd, pb, and zn the multivariate statistical methods have not isolated one anthropogenic group with typical heavy metals such as pb, zn, and cd. this was expected since the appearance of such an association is more characteristic around the ironworks and smelters, in areas where long lasting anthropogenic impact is evident. their absolutely anthropogenic tendency is present however comparing their average values with eurotable 3: matrix of correlation coefficients (n = 52). al 1.00 as 0.04 1.00 ba 0.33 0.38 1.00 ca 0.71 0.04 0.17 1.00 cd 0.17 –0.05 0.17 0.14 1.00 co –0.05 0.59 0.16 –0.05 0.19 1.00 cr 0.14 0.42 0.29 0.03 0.30 0.43 1.00 cu 0.38 0.30 0.66 0.32 0.28 0.15 0.50 1.00 fe 0.38 0.44 0.56 0.09 0.36 0.34 0.71 0.62 1.00 k 0.35 0.27 0.64 0.24 –0.07 0.12 0.16 0.65 0.39 1.00 li 0.23 0.47 0.45 0.25 0.25 0.43 0.72 0.63 0.63 0.39 1.00 mg 0.70 0.03 0.29 0.75 0.16 0.10 0.16 0.41 0.26 0.46 0.31 1.00 mn 0.22 0.30 0.50 0.05 0.36 0.30 0.52 0.61 0.71 0.30 0.50 0.14 1.00 na 0.07 –0.36 –0.02 0.17 0.02 –0.09 –0.40 –0.13 –0.26 0.09 –0.27 0.44 –0.09 1.00 ni 0.31 0.44 0.44 0.28 0.28 0.44 0.88 0.68 0.74 0.40 0.81 0.44 0.65 –0.17 1.00 pb –0.03 –0.14 –0.01 –0.14 0.14 –0.07 0.24 0.04 0.05 –0.20 –0.09 –0.19 0.02 –0.22 0.12 1.00 sr 0.71 0.03 0.36 0.75 0.30 0.06 0.14 0.45 0.27 0.25 0.29 0.69 0.28 0.40 0.39 –0.02 1.00 zn 0.22 0.31 0.32 0.42 0.29 0.25 0.25 0.45 0.26 0.30 0.44 0.35 0.11 –0.05 0.35 –0.13 0.31 1.00 al as ba ca cd co cr cu fe k li mg mn na ni pb sr zn r ≥ 0.5 and <0.7 – underlined; r ≥0.7 and <1.0 bolded table 4: matrix of dominant rotated factor loadings (n = 52, 13 selected elements). f1 f2 f3 com cr 0.88 0.07 0.13 79.5 ni 0.83 0.31 0.31 87.6 li 0.77 0.22 0.33 75.0 co 0.73 -0.06 -0.09 55.1 fe 0.68 0.15 0.46 70.1 as 0.66 -0.10 0.22 49.5 ca 0.00 0.92 0.04 84.1 sr 0.11 0.87 0.16 78.6 mg 0.11 0.85 0.21 78.3 al 0.04 0.83 0.24 75.2 ba 0.23 0.13 0.84 78.3 k 0.09 0.21 0.84 76.5 cu 0.40 0.31 0.73 78.0 var 28.8 25.8 19.7 74.3 f1 … f3 – factor loadings; com – communality (%); var – variance (%) stafilov et al.: geochemical properties of topsoil around the open coal mine and oslomej thermoelectric power plant, r. macedonia geologia croatica 41 pean averages, as they exceed these by x3 or x4 (tables 1 and 2). it is significant that these elements do not show significant statistical differences between samples collected at isolated lithological units (table 2), meaning that their distributions are influenced by anthropogenic factors. when considering their spatial distributions (fig. 5) it is necessary to observe more factors: (1) impact of the coal open pit and the „oslomej” thermal power plant, (2) leaching from the „tajmište” abandoned mine and a subsequent deposition of heavy metals in the alluvial sediments of the river zajaska, and (3) impact of „metal industry kičevo”. for this purpose, several groups of samples that cover the aforementioned areas have been determined. for the cd, zn, and pb distribution pattern, 39 sampling sites were selected to determine their background values, 8 samples east of the „oslomej” open pit, and 5 samples around the river zajaska. for example, the group of 12 samples collected in east kičevo were selected to represent the distribution of zn. based on the result of spatial distribution and average values of cd (fig. 5a) in the aforementioned groups, we cannot talk about the anthropogenic impact because the calculated averages are borderline in terms of a statistically significant difference. the average concentrations of cd along the river zajaska and oslomej are up to 50% higher than the background values, but much lower than the target values of the new dutch list. some weak anthropogenic trends are noticed, but they are hidden by some background fluctuations because the surrounding paleozoic rocks are enriched with these element (fig. 5b). it is a completely different case for the distribution of pb (fig. 5b). statistical analysis shows highly significant differences between the average background values (64 mg/kg pb in range 1.7 220 mg/kg), along the river zajaska (170 mg/kg pb, in range 120-220 mg/kg), and the area east of the „oslomej” open pit (200 mg/kg pb, in range 110 to 430 mg/ kg). the aforementioned values exceed the target values but are still lower than intervention values (new dutch list). a halo dispersion pattern with high values of pb occurs east of the open pit in accordance with the dominant wind direction and wind intensity and can be attributed exclusively to atmospheric transport and deposition (fig. 5b). the average values of zn among the background samples show quite significant differences (94 mg/kg of zn, in range 110 to 230 mg/kg) from the group of samples from the urban area of kičevo (320 mg/kg of zn, in range 130 to 1700 mg/kg). the average values of zn exceed the target values and even at some certain sampling sites, the intervention values determined by the new dutch list. in this case there is a clear anthropogenic influence on the contamination halo, and high concentrations of zn are consequences of the „metal industry kičevo” (fig.5c) operation. this assumption is proven by the position and shape of the contamination aureole, as well as the wind direction. comparison with the distribution of pb (fig. 5b), indicates that this contamination halo solely depends on atmospheric transport. 6. conclusion the aim of this study was to present the results of an initial systematic investigation of the spatial distribution of various chemical elements in surface soil over of the kičevo region known for its coal mine and „oslomej” thermal power plant. even the sparse soil measurements have been adequately sensitive for determination of the main geochemical associations and their connection to anthropogenic influence and lithological background. following the results of statistical analysis and the trends shown on the geochemical maps, three natural geochemical associations in soil have been defined (cr-ni-li-co-fe-as; al-ca-mg-sr; and ba-k-cu). their sources are mainly natural phenomena and closely dependent on the lithology. even the distributions of typical heavy metals such as pb and zn are not isolated into anthropogenic geochemical association by multivariate statistical methods, but they still figure 4: distribution of factor scores regarding the basic lithological units: a – factor 1 (cr, ni, li, co, fe and as); b – factor 2 (ca, sr, mg and al); c – factor 3 (ba, k and cu). geologia croatica 67/1geologia croatica 42 fi gu re 5 : s pa tia l d is tr ib ut io n of a nt hr op og en ic al ly in tr od uc ed e le m en ts : a – c ad m iu m ; b – l ea d; c – z in c stafilov et al.: geochemical properties of topsoil around the open coal mine and oslomej thermoelectric power plant, r. macedonia geologia croatica 43 show trends of local anthropogenic enrichment. firstly, the distribution of pb is not only influenced by the open coal pit and „oslomej” thermal power plant but also by river transport. eroded material from the iron mine „tajmište” had been transported in alluvial sediments of the river zajaska. the distribution of zn is influenced by the „metal industry kičevo” operation. according to the distributions of heavy metals, especially pb and zn, it was possible to determine two main types of transportation, river transport and atmospheric transport respectively. distribution of pb is result of river transport, but distribution of zn is solely result of atmospheric transport. references balabanova, b., stafilov, t., bačeva, k. & šajn, r. (2010): biomonitoring of atmospheric pollution with heavy metals in the copper mine vicinity located near radoviš, republic of macedonia.– journal of environmental science and health, part a, 45, 1504–1518. balabanova, b., stafilov, t., šajn, r. & bačeva, k. (2011): distribution of chemical elements in attic dust as reflection of lithology and anthropogenic influence in the vicinity of copper mine and flotation.– archives of environmental contamination toxicology, 61, 173–184. barandovski, l., cekova, m., frontasyeva, m.v., pavlov, s.s., stafilov, t., steinnes, e. & urumov, v. (2008): atmospheric deposition of trace element pollutants in macedonia studied by the moss biomonitoring technique.– environmental monitoring and assessment, 138, 107–111. borůvka, l., vacek, o. & jehlička, j. (2005): principal component analysis as a tool to indicate the origin of potentially toxic elements in soils.– geoderma, 128, 289–300. chen, t.b., zheng, y.m., lei, m., huang, z.c., wu, h.t., chen, h., fan, k.k., yu, k., wu, x. & tian, q.z. (2005): assessment of heavy metal pollution in surface soils of urban parks in beijing, china.– chemosphere, 60, 542–551. darnley, a.g., björklund, a., bolviken, b., gustavsson, n., koval, p.v., plant, j.a., steenfelt, a., tauchid, m., xuejing, x., garrett, r.g. & hall, g.e.m. (1995): a global geochemical database for environmental and resource management. recommendations for international geochemical mapping.– final report of igcp project 259, unesco publishing, paris, 122 p. davidson, c.m., urquhart, g.j., biasioli, m., duarte, a.d., diaz-barrientos, e., grcman, h., hossack, l., hursthouse, a.s., madrid, l.s. rodrigues, s. & zupan, m. (2006): fractionation of potentially toxic elements in urban soils from five european cities by means of a harmonised sequential extraction procedure.– analytica chimica acta, 565, 63–72. davis, j.c. (1986): statistic and data analysis in geology.– willey in sons, new york, 651 p. dumurdjanov, n., stojanov, r. & petrovski, k. (1972): basic geological map of sfry 1: 100000, sheet kruševo – in macedonian.– federal geological survey, beograd, 58 p. gjorgieva, d., kadifkova-panovska, t., bačeva, k. & stafilov t. (2010): selected microelements in herbs of medicinal importance growing in polluted and unpolluted area.– archives of industrial hygiene and toxicology, 61, 297–303. gjorgieva, d., kadifkova-panovska, t., bačeva, k. & stafilov, t. (2011): assessment of heavy metal pollution in r. macedonia using plant assay.– archives of environmental contamination toxicology, 60, 233–240. kabata-pendias, a. & pendias, h. (2001): trace elements in soil and plants, third edition, crc press, boca raton. lazarevski, a. (1993): climate in macedonia.– kultura, skopje. le maitre, r.w. (1982): numerical petrology, statistical interpretation of geochemical data.– elsevier, amsterdam, 281 p. petkovski, p. & ivanovski, t. (1973): basic geological map of sfry 1:100000, sheet kičevo – in macedonian.– federal geological survey, beograd, 69 p. pruvot, c., douay, f., herve, f. & waterlot, c. (2006).heavy metals in soil, crops and grass as a source of human exposure in the former mining areas.– journal of soils and sediments, 6, 215–220. reimann, c., albanese, s., batista, m.j., bel-lan, a., birke, m., cicchella, d., demetriades, a., de vivo, b., de vos, w., dinelli, e., duris, m., dusza-dobek, a., ernstsen, v., flight, d., gilucis, a., gosar, m., gregorauskiene, v., gulan, a., hayoz, p., halamic, j., haslinger, e., hrvatovic, h., ion, a., ivanovna, y., johnson, c., jordan, g., kisivilla, j., klein, p., kwecko, p., lax, k., lima, a., locutura, j., malyuk, b.i., maquil, r., marku, s., martins, l., mazreku, a., messina, a., o’connor, p., ottesen, r.t., pasieczna, a., petersell, w., reeder, s., salpeteur, i., schedl, a., sefcik, p., slaninka, i., sorsa, a., selinus, o., stafilov, t., tarvainen, t., trendavilov, v., utermann, j., valera, p., vidojevic, d. & volden, t. (2008): eurogeosurveys geochemical mapping of agricultural and grazing land soil of europe (gemas), field manual, ngu report 2008.038.– geological survey of norway, 46 p. reimann, c., filzmoser, p. & garrett, r.g. (2002): factor analysis applied to regional geochemical data: problems and possibilities.– applied geochemistry, 17, 185–206. salminen, r., batista, m.j., bidovec, m., demetriades, a., de vivo, b., de vos, w., duris, m., gilucis, a., gregorauskiene, v., halamić, j., heitzmann, p., jordan g., klaver g., klein, p., lis, j., locutura, j., marsina, k., mazreku, a., o’connor, p.j., olsson, s.a., ottesen, r.t., petersell, v., plant, j.a., reeder, s., salpeteur, i., sandström, h., siewers, u., steenfelt, a. & tarvainen, t. (2005): geochemical atlas of europe, part 1, background information, methodology and maps.– geological survey of finland, espoo, 526 p. snedecor, g.w. & cochran, w.g. (1967): statistical methods.– the iowa state university press, ames, iowa, 575 p. stafilov, t., šajn, r., pančevski, z., boev, b., frontasyeva, m.v. & strelkova, l.p. (2008a): geochemical atlas of veles and the environs.– faculty of natural sciences and mathematics, skopje. stafilov, t., šajn, r., boev, b., cvetković, j., mukaetov, d. & andreevski, m. (2008b): geochemical atlas of kavadarci and the environs.– faculty of natural sciences and mathematics, skopje. stafilov, t., šajn, r., pančevski, z., boev, b., frontasyeva, m.v. & strelkova, l.p., (2010a): heavy metal contamination of surface soils around a lead and zinc smelter in the republic of macedonia.– journal of hazardous materials, 175, 896–914. stafilov, t., šajn, r., boev, b., cvetković, j., mukaetov, d., andreevski, m. & lepitkova, s., (2010b): distribution of some elements in surface soil over the kavadarci region, republic of macedonia.– environmental earth sciences, 61, 1515–1530. stafilov, t., balabanova, b., šajn, r., bačeva, k. & boev, b., (2010c): geochemical atlas of radoviš and the environs and the distribution of heavy metals in the air.– faculty of natural sciences and mathematics, skopje. šajn, r. (2003): distribution of chemical elements in attic dust and soil as reflection of lithology and anthropogenic influence in slovenia.– journal de physique, 107, 1173–1176. geologia croatica 67/1geologia croatica 44 šajn, r. (2005): using attic dust and soil for the separation of anthropogenic and geogenic elemental distributions in an old metallurgic area (celje, slovenia).– geochemistry: exploration, environment, analysis, 5, 59–67. šajn, r. (2006): factor analysis of soil and attic-dust to separate mining and metallurgy influence, meza valley, slovenia.– mathematical geology, 38, 735–747. šajn, r., halamić, j., peh, z., galović, l. & alijagić, j. (2011): assessment of the natural and anthropogenic sources of chemical elements in alluvial soils from the drava river using multivariate statistical methods.– journal of geochemical exploration, 110, 278–289. wilson, b., lang, b. & pyatt, f.b. (2005): the dispersion of heavy metals in the vicinity of britannia mine, british columbia, canada.– ecotoxicology and environmental safety, 60, 269–276. manuscript received june 12, 2013 revised manuscript accepted february 18, 2014 available online march 21, 2014 geologia croatica 45 173175 zagreb 1992 o tome kako se ne bi smjelo znanstveno raditi: odgovor na osvrt d.jamičića jakob pamić uvod koncem 1989. godine dobio sam od tadašnjeg glavnog urednika vjesnika tekst jamičića na 10 stranica pod nazivom "komentar" u kojem se sadržajno neadekvatno osvrće na moj članak ''zonalnost hercinskog metamorfnog kompleksa ... " (pamić, 1989). budući da je, uz tu neadekvatnost, bio pisan na neučtiv i veoma ružan način, neprimjeren za znanstvenu komunikaciju, uputio sam tadašnjem uredničkom odboru vjesnika protestno pismo, naglasivši da bi bilo sramotno za našu zagrebačku geoznanost da se tiska taj tekst. nakon toga je jamičić, na temelju intervencije tadašnjeg glavnog i odgovornog urednika, načinio novu verziju teksta (sad pod nazivom "osvrt"), koja je nešto skraćena, i mada manje neučtivo pisana, još uvijek neadekvatna za tisak jer je pamfletskog karaktera. zbog toga tadašnji glavni i odgovorni urednik i uredništvo, koje je bilo sastavljeno od znanstveno kompetentnijih i životno zrelijih ljudi, ne prihvaćaju ni tu novu verziju i odbijaju da se ona tiska. u međuvremenu dolazi do smjene . uredništva vjesnika, u koje je odabran i jamičić, koji zloupotrebljava taj status i ponovno predaje već jednom recenziran i odbijen osvrt za tisak, a novi glavni i odgovorni urednik donosi ishitrenu odluku o njegovom tiskanju. pisanje osvrta na nečiji objavljeni znanstveni rad je uobičajena praksa u svijetu; on se obično piše kratko na 1-2 stranice i fokusira 1-2 sporna pitanja koja se razmatraju sa ciljem njihovog optimalnog rješenja. ti su komentari uvijek pisani na korektan način i pristojno, bez teoretske mogućnosti da se vrijeđa autor čiji se rad komentira. s druge strane, autor komentiranog rada dobiva od glavnog urednika cjeloviti manuskript osvrta i na njega, jasno opet na pristojan način, daje svoj odgovor te se osvrt i odgovor tiskaju zajedno, jedan pored drugog, u istoj svesci časopisa. to su ta demokratska pravila igre koja vladaju svtfda u civiliziranom znanstvenom svijetu i za njih je dobro znao prethodni glavni urednik, kada mi je dost~ . :) j<>mičićev i komentar i osvrt. to je također znao i sadašnji glavni urednik (na to sam ga upozorio), no on ipak nije poštivao pravila igre i zakinuo mi je to moje demokratsko pravo da moj odgovor iziđe zajedno s osvrtom jamičića u istoj svesci. ne treba biti jako pam ,tan pa da se shvati da efekti nisu isti ako se osvrt i odgovor tiskaju ili 1ie tiskaju zajedno, jer je u posljednjem slučaju onaj koji odgovara zakinut i oštećen, institut za geolo~ka istraživanja, sachsova i, zagreb i sticajem okolnosti može doći u poziciju da uopće ne može odgovoriti. no što je tako ispalo neka je na diku glavnom uredniku! · odgovor d. jamičiću najamičićev osvrt veoma je teško korektno odgovoriti jer je jako emotivno nabijen, na mnogim mjestima sitničavo, nekorektno i uvredljivo pisan. pored toga, ima izrazito polemički karakter, tako da je teško izvući sadržaj pravog znanstvenog spora koji bi bio adekvatan za znanstvenu raspravu. naime, jamičić {1991) polemički navodi čitav niz problema o kojima nas dvojica imamo različita mišljenja, a za koja je svaki od nas već objavio svoju argumentaciju. jeste, činjenica je da ja, za razliku od jamičića, smatram da su stijene psunjskog (progresivnometamorfnog) komleksa ravne gore i sjevernih padina fapuka identične petrološko-geološke tvorevine jer oba karakterizira ista penetrativna metamorfna zonalnost, itd. on je mišljenja da ·je slavonski kristalinski kompleks u cje.~ni polimetamorfan, a ja dijelim mišljenje raffaellija (1965) da je on u osnovi monometamorfan, ali polifazno deformiran. isto se tako ne slažemo oko stratigrafskog položaja radlovačkog kompleksa za čije rješavanje bi trebalo još mnogo egzaktnih paleontoloških i radiometrijskih podataka. jamičić ima pravo nisam · bio dovoljno terminološki precizan kad sam naveo da on taj odnos uglavnom objašnjava tektonski, a trebao sam reći tektonsko-eroziono. no iz kon teksa se vidi da sam ja to mišljenje suprostavljao onom drugom po kojem su ta dva kompleksa genetski srodni. nas dvojica se ne slažemo ni u objašnjavanju položaja kloritoidnih škriljavaca. radi se o veoma složenom problemu o kojem je i sam jamičić dosad već iznosio različita mišljenja. stvarno nema smisla dalje navoditi u čemu se sve nas dvojica ne slažemo, jer su te naše razlike u osnovi uvjetovane našim različitim pristupima i metodama koje primjenjujemo. moja rješavanja problema slavonskog kristalina temelje se na mineraloško-petrološko­ radiometrijskoj obradi sistematski uzetih uzoraka na . dugačkim repernim profilima, što jamičić dosad nije radio. zbog nedostatka fosila prvi sam u nas uveo sistematsku radiometrijsku metodu, koja je dala, i pored svojih manjkavosti, veoma korisne i upotrebljive podatke koji su do temelja izmijenili jamičićeve znanstveno 174 nezasnovane sij'aligrafske mzdiobe. jamičić pri geološkom kartiran ju vrti strukturološlru obradu na osnovi koje daje tektonsku interpretaciju u smis!u sukcesivnosti deformacijskih faza, što je manstveno sasvim korektno. no jamičić iz te tektonske interpretacije izvodi stratigrafske zaključke obratnim redoslijedom, definirajući taksativno pojedine komplekse kao bajkalide i kaledonide, što je znanstveno nekorektno. naime, još je delon (1969) radiometrijski dokazao da ti, tako neadekvatno definirani jamičićevi kaledonidi, pripadaju zaprayo hercinskom ciklusu. taj deleonov podatak kasnije je još potpunije dokumentiran s nekoliko desetaka novih radiometrijskih određivanja (pamić et al., 1988). dakle, za stratigrafska definiranja kristalinskih kompleksa nije dovoljna samo strukturološka obrada i nikakvi schmidtovi dijagrami ne mogu zamijeniti zasad jedino egzaktne radiometrijske podatke. kada se radi o tako bitno različitim pristupima u rješavanju znanstvenih problema, onda je veoma teško voditi bilo kakve racionalne diskusije. konačno, jamičić i ja smo se, nakon višegodišnje dosja plodne suradnje (pamićetal.,1984i 1984a;pamići jamičić,1986), rastali tek onda kad je on odbio da zajedno radimo dalje i na izotopno-geološkim starostima, jer se već prvi dobiveni podaci nisu uklapali u njegove koncepcije i sheme. no i pored tih razlika u mišljenjima i pristupima, meni nije palo na pamet da pišem komentare na jamičićeve radove. iskustva koja se steknu kroz čitav radni vijek u oblasti geologije upozoravaju nas da proces spoznaje u području geoloških manosti ne završava našim individualnim doprinosom pa ma kako on bio velik. narcisoidnost i aprioristički stavovi oko geoloških problema, čija je složenost uvjetovana nizom faktora ' i širih regionalnih okolnosti ne pomažu razvoju geoznanosti. zbog jako emotivnog naboja, jamičićev osvrt krcat je nekim osobnim problemima koji nemaju mjesta u znanstvenom časopisu. veoma je neprimjereno da on sam ističe svoj (i vragovićev) veliki doprinos u izradi ogk slavonskih planina, dokumentira jući io sa 70.000 točaka opažanja i 7.000 petrografskih izbrusaka, što je djelo cjelokupne ekipe i tima laboratorijskih specijalista. no i pored tog velikog broja izbrusaka {od kojih sam -usput budi rečenoi ja odredio oko 20%), činjenica je da su sva kartografska izdvajanja u metamorfnim terenima temeljena na indeks mineralima koje je odredio još kišpatić (1891, 1892 i 1910)! s druge strane, u osvrtu ima puno neke neopravdane preosjetljivosti,jer ja navodno "minoriziram rezultate dugogodišnjih istraživanja". to je čista insinuacija, što dokazuje svaki moj objavljeni članak gdje sam objektivno navodio sve dosadašnje radove, pa i jamičićeve. jasno, pri tome se ne mogu navoditi svi detalji. primjerice, ja nisam išao ponovno kartirati područje krndije pa nisam mogao ići u korelaciju s onim što je na ogk izdvojeno, nego sam sistematski snimao i uzorkovao profite i s dobivenim lokalnim stupovima pokazao da se na taj način geologia croatica 45 mogu izvršiti detaljnija metamorfna zoneografska izdvajanja. pri tome se nisam osvrtao na izdvajanja na ogk, i to baš zato da ne bih isticao svoju detaljniju razdiobu, što bi moglo ličiti na polemiku. slično je i sa slučajem zapažene inversne zonalnosti. ja sam je dijagnosticirao i objektivno naveo da ju je jako teško objasniti, navodeći da bi se ona mogla, možda, objašnjavati kretanjima duž našičkog i orahovičkog rasjeda. istina, pri tome sam jamičićev rad cititao na kraju rečenice, no ne da bih ga omalovažio, kako on to uvrijeđeno napominje, nego zato što je tako najbolje odgovaralo formulaciji moje rečenice. isto tako nisam minorizirao j amičića tvrdeći da kristal inski kompleks krndije "dosad nije bio detaljnije petrološki izučavan". ta moja tvrdnja je istinita, jer postoji objavljen samo jedan petrološki rad o metamorf~im stijenama {kišpatić, 1910). sasvim je sigurno da tumači listova i jamičićev rad iz 1983. godine, koliko god su veoma značajna geološka djela, ne predstavljaju znanstvene petrološke radove. · j amičić, koji je tek nedavno dobio znanstveni status (da li?), jako je nekorektan i bezrazložno prepotentan kada ulazi u ocjenjivanje moje dugogodišnje znanstvene aktivnosti, na što, s obzirom na moju užu struku, nema ama baš nikakvih kvalifikacija. moje objavljene radove stavlja pod navodnike "znanstveni članak" čime diskvalificira one kompetentne koji su takvu kvalifikaciju dali, ali iznad svega, pokazuje svoju ličnost u pravoj slici. u jamičićevom osvrtu ima puno sitničavosti i omalovažavanja, i to pisano na takav način koji vodi potpunom diskreditiranju kritizirane osobe. ja, navodno, nisam na profilu vidio gabre (nisam ih ni tražio, budući da sam radio na zoneografiji metamorfita), zatim ne citiram njegove ranije objavljene podatke, pa insinuira da ga se potkrada (što opovrgavaju svi moji objavljeni radovi), itd. a u svojoj vlastitoj narcisoidnosti ne primjećuje da u tom svom kratkom osvrtu citira sam sebe čak 19 puta! netočna je j amičićeva tvrdnja da radiometri jski podaci "dakle ne dokazuju" hercinsku starost. dokazuju je, i te kako je dokazuju, i to jednoznačno za njegov "kaledonski" migmatitno-granitni kompleks čak s dvije sr-izokrone. isto je tako netočna njegova tvrdnja da prelazim preko objavljenih podataka koji ukazuju na starije orogeneze, što dokazuje i on sam, citirajući moju rečenicu: "on (tj. pamić-primjedba autora) progresivno­ metamorfni kompleks..... za vrijeme bajkalske orogeneze". i ta moja rečenica nije nikakvo imputiranje neznanja, kako to u svojoj preosjetljivosti navodi jamičić, jer je u njoj poanta na podvučenom dijelu rečenice. a koliko ja istinski uvažavam njegove strukturološke podatke najbolje dokazuje moja najnovija monografija (p .ami~.l.9~q.'"čiji ~p~ dat. u ovom broju geološkog vjesnika (majer, 1992). neprijatno je i tužno odgovarati na ovakve osvrte! no morao sam to učiniti jer je kolega jamičić, vođen nekim ružnim emocijama, pokušao da me stavi pamić : o tome kako se ne bi smijelo... . neopravdano i na nedoličarinačinna · ~stup srama". (ima onanarodna: "došlo vrijeme da je pile kvočku uzjašlro"). budući daje on meni starijem. "održao lekciju", dozvolit ću si da ja njemu mlađem, sasvim dobronamjerno, preporučim slijedeće: · · (l) okanite se polemika i sjedite, stvarajte i pišite znanstvene radove kad već imate toliko faktografije; (2) morate shvatiti da taj naš divni kristalin slavonije nije samo vaše (i vragovićevo)leno i, konačno, (3) da je tolerancija (pa i pristojnost) osnova svake ljudske pa i znanstvene komunikacije . . · glavnom uredniku dobili smo novi i u tehničkom pogledu bolji i osvježeniji geološki vjesnik, na čemu ti treba čestitati. no u sadržajnom pogledu, dozvoljavanjem tiskanja ovakvih osvrta i odgovora, činiš da miš časopis istovremeno poprima elemente "žute štampe", što nije na čast hrvatskoj geoznanosti. mada je svaki autor odgovoran za svoj znanstveni rad (osvrt itd.), ipak glavni urednik ima odgovornost da vodi računa o nekim temeljnim stvarima: da radovi ne sadrže znanstvene neistine, da su na određenoj razini i da su pristqjno pisani. jamičićev tekst pun je osobnih vrijeđanja, što sam ja naprijed djelomice prokomentirao. no pustimo na stranu sva ta njegova vrijeđanja, insinuacije itd., s kojima je on sam samo "uslikao" samog sebe. ima, međutim, u njegovom tekstu nešto što nije smjelo promaći tvojoj odgovornosti, nešto na što se uopće ne može odgovarati. naime, u početnim dijelovima njegovog teksta stoji da je pamić "1981. prvi puta počeo raditi u kristalinskim terenima", što ne predstavlja samo grubu neistinu nego i tešku klevetu, koja duboko vrijeđa ljudski i znanstveni dignitet čovjeka čiji je cjelokupni znanstveni opus vezan baš za kristalinske stijene. tebi, glavni uredniče, a i svima oko nas, pai uevropii u svijetu, veoma dobro je poznata moja znanstvena aktivnost i moje djelo. dozvolivši da se tiska gore navedeni tekst jamičića, ne samo da se nisi ponašao kao odgovorni urednik nego si poremetio osnovni red stvari, jer se nigdje u znanstvenom svijetu ne dozvoljava da netko neadekvatno kvalificiran tako grubo i na javan način kleveće nekog koji je u nekoj drugoj znanstvenoj oblasti maksimalno kvalificiran. nadajući se da ćeš objektivno i samokritično sagledati svoj propust, molim te i zahtijevam da se u slijedećem vjesniku javno ispričaš 'za klevetu koja mi je učinjena. u protivnom bit ću prisiljen potražiti zadovoljštinu na drugon adekvatnijern mjestu. pripomena uredništva: 175 literatura deleon,g.(1969): pregled rezultata određivanja apsolutne geološke starosti granitoidnih stena u jugoslaviji. rad. lnst.geol.-rud.istr.nukl.sir., 6, 165'-182. jamičić,d.(1983): strukturni sklop metamorfnih stijena krndije i južnih padina papuka. geol. vjesnik, 36, 51-72. jamičić,d.(1991): osvrt na rau j.pamiča, "zonalnost hercinskog metamolfnog kompleksa krndije u slavoniji (sjev. hrvatska, jugoslavija)".geol.vjesnik,44, 321323. kišpatić,m.(1891): kloritoidni škriljavac iz psunja. rad jazu, 104, 3-8. kišpatić,m.(1892): prilog geološkom poznavanjupsunja. -rad jazu, 109, 1-57. kišpatić,m. (1910): disthen-, sillimanitund staurolitftihrende schiefer aus dem krndijagebirge in kroatien.centralbl. mineral. etc., 5, 578-586. majer,v.(1992): prikaz monografije: ''pamić,j. i lanphere, m.m.(1992): hercinske granitne i metamorfne stijene ..... ". geol.vjesnik, 45, u tisku. pamić,j.(1989): zonalnost hercinskog metamorfnog kompleksa krndije u slavoniji (sjeverna hrvatska, jugoslavija). geol.vjesnik, 42, 79-92. pamić,j.(1991): hercinske granitne i metamorfne stijene papuka, psunja, krndije i okolne podloge panonskog bazena u slavoniji (sjeverna hrvatska). monografija. -geologija, 34, 81-253. pamić,j.,jamičić,d.&crnko,j.(l984): bazične i ntermedijame magmatske stijene iz metamorfita središnjih dijelovapsunja u slavoniji.geol. vjesnik, 37, 127-144. pamić ,j .,jamičić,d.&crnko,j .(1984a): petrološki prikaz ultramafita iz metamorfnog kompleksa središnjih dijelovapsunja.rad jazu, 141 (20), 93-104. '· . p amić,j.,jamičić,d.(1986): metabasic intrusive rocks from the paleozoic radi ovac complex of mt. papuk in slavonija (northern croatia).rad jazu, 424(21), 97-127. pamić,j., lanphere,m. & mckee,e.(1988): radiometric ages of metamorphic and associated igneous rocks of the slavonian mountains in southern parts of the pannonian basin.acta geol., 18, 13-39. raffaelli,p.(1965): metamorfizam paleowjskih pelitskih škriljavaca u području ravne gore.geol.vjesnik, 18,61-111. primjedbe koje je gospodin pamić uputio glavnomuredniku-giede neobjavljivanja odgovora na osvrt jam ičića u istom broju časopisa ukazuje na nepoznavanje zakona o javnom informiranju republike hrvatske (narodne novine br.22 od 17. travnja 1992. god.; o tome jednaki propisi vrijedili su i u prethodnom zakonu). prema 43 .članku cit. zakona nije dopušteno u istom broju časopisa objaviti članak i osvrt na njega. u skladu sa zakonskim odredbama odgovor uredništva i glavnog urednika gospodinu pamić u slijedi u idućem broju "geologia croatica" .  geothermal properties of the northern part of the island of rab  miron kovačić croatian geological survey, zagreb, croatia; (miron.kovacic@hgi-cgs.hr) doi: 10.4154/gc.2013.03 geologia croatica 66/1 29–37 6 figs. 7 tabs. zagreb 2013 geologia croaticageologia croatica atia (jelić et al., 1995, 2005) refers to a geothermal gradient and density of thermal flux below the average values. this is also typical for the coastal area of slovenia (rajver & ravnik, 2002; ravnik et al., 1995). according to kovačić (2001) geothermal water in the coastal zones of croatia is not in use due to the absence of geothermal areas. 2. geological setting the geological structure of the study area is described on the basis of geological exploration of the terrain, and production of basic geological maps (mamužić & milan, 1969, 1973). upper cretaceous limestones with dolomite interbeds are the oldest sediments exposed at the surface. they are generally grey-brown, well-stratified limestones with thinner or thicker intercalations of dolomite limestone and white and yellowish, mostly non stratified, crystalline limestone. lithological differences that exist in some observed locations are small and are reduced to a different mutual arrangement of gray-brown and white limestone and dolomitic limestone interbeds. previous studies determined these deposits 1. introduction geothermal exploration of the northern part of the island of rab was conducted by the croatian geological survey (cgs). all field and laboratory studies were conducted by the author during the autumn of 2008. the aim of this study was to determine the geothermal properties and the possibility for utilising geothermal energy in the research area. approximately 27 km2 were surveyed. field investigation consisted of geological prospection of the study area, selection of typical rock samples of individual lithological units to determine their geothermal parameters, inspection of springs and measurements of the basic physico-chemical characteristics of water. laboratory studies were conducted in the laboratory of cgs, and included measurements of geothermal properties of rock samples. there had been no similar previous geothermal research conducted in the area. several previous publications discussed the geothermal characteristics of the wider area. description of temperatures and thermal fluxes for the coastal area in the territory of croab stra ct the results of geothermal research in the northern part of the island of rab are presented. this research was carried out by the croatian geological survey on the initiative of the municipal administration of lopar. the aim of the study was to determine the geothermal features and possibilities for utilising geothermal energy in this area. field research included inspection of natural springs, together with the geological screening and sampling of typical rocks. laboratory studies focused on the measurement of thermal parameters of rock samples collected in the field to demonstrate their ability to conduct and accumulate heat. research has shown that spring waters do not originate from deep aquifers and that the carbonates of upper cretaceous limestones and tertiary foraminiferal limestones have relatively favourable values of geothermal parameters and are able to conduct and accumulate heat. given the geological structure, as well as the hydrogeological and geothermal parameters of the study area, the use of geothermal energy from deep boreholes would not be profitable. cost-effective heating and cooling could be provided using shallow boreholes and ground source heat pumps in layers with favourable thermal properties. keywords: geothermal energy sources, heat conduction, heat pumps, rab, croatia geologia croatica 66/1geologia croatica 30 as being cenomanian – turonian in age. their mean thickness is about 600 m (figure 1). as mentioned, turonian and senonian deposits that consist of light grey and white, occasionally reddish limestone, were continuously deposited over the cenomanian. these lithological layers are almost indistinguishable from the white and yellowish limestones of the cenomanian and turonian. the average thickness of these layers in the wider area is 150–200 m. all of the upper cretaceous (k2) deposits are characteristic of shallow and warm seas. upper cretaceous deposits are located on the southwest side of the study area where they form an anticline of dinaric strike, as well as on most parts of the islands of st. grgur and goli. upper cretaceous sediments are followed by transgressive tertiary foraminiferal limestones. a geological unconformity is clearly marked by small bauxite deposits and occurrences that may be encountered at several places on the islands of rab and goli. according to mamuzić and milan (1973) the foraminiferal limestones belong to the lower and middle eocene, and the average thickness in the wider area is from 100 to 150 m. foraminiferal limestone outcrops along the edges of these anticlines. middle and upper eocene flysch was deposited continuously on foraminiferal limestones. according to mamuzić & milan (1973) and marinčić (2009), they represent typical flysch sediments deposited in a deeper basin. marjanac & marjanac (2007), suggest these sediments were figure 1: road cut through the upper cretaceous sediments (photo: m. kovačić, 2008). figure 2: tertiary marls and sandstones of the lopar peninsula (photo m. kovačić, 2008). miron kovačić: geothermal properties of the northern part of the island of rab geologia croatica 31 the youngest deposits are quartz sands of quaternary age. they are characterized by good sorting, rounded grains and the absence of a lime component indicating a long period of transport. the sands were derived from older flysch sediments. according to previous studies, the thickness of these layers is the greatest in lopar, at about 6 m (mamužić & milan, 1973). quaternary sediments are located in the area between the aforementioned cretaceous carbonate anticline to the southwest and the flysch syncline of the lopar peninsula to the northeast, and are observed in deep valleys of the lopar peninsula (see figure 4). the upper cretaceous and tertiary are not subdivided into stages on the map. deposited in a shallow sea. they are characterized by the interchanges of fine and coarse grained sediments. the lower part is dominated by marl, while the upper part consists of sandstone with layers of marl. intercalated marls are of different thicknesses with decametric width. in some places, horizontal and vertical transitions in the sandstone and marl are common suggesting that deposition took place in an estuary (marjanac & marjanac, 2007) (figure 2). bodies of biocalcarenite with abundant nummulites appear in places (figure 3). the entire lopar peninsula on rab island is composed of tertiary flysch sediments. structurally, it is a syncline following the dinaric strike. these layers are the source material for the famous sandy beaches of the lopar peninsula. figure 3: biocalcrudite – nummulitic limestone of tertiary age (photo m. kovačić, 2008). figure 4: geological map of the research area m 1:100.000 (k2 – the upper cretaceous sediments, tc – tertiary deposits, q – quaternary sediments) (by: mamužić & milan, 1969). geologia croatica 66/1geologia croatica 32 3. natural springs in the investigated area observations were made on the condition of the major springs in the study area (those marked on the 1:25000 topographic map sections supetarska draga and rab, and a few springs discovered during fieldwork). the aim of this study was to determine the basic physico-chemical properties of water that could indicate possible flow from deeper aquifers. the following properties of water were determined during fieldwork: clarity, colour, odour and taste. measured parameters were: temperature (t), electrolytic conductivity (ec) and the proportion of total dissolved solids (tds). a survey of the springs was carried out during the hydrological minifigure 5: map showing the springs and sampling locations (sampling locations on goli island not included). figure 6: jerko water spring – jerkovac (photo m. kovačić, 2008). miron kovačić: geothermal properties of the northern part of the island of rab geologia croatica 33 mum. spring locations are shown in the overview map (figure 5), indicated by the following labels: i-1 (spring in stolac cove), i-2 (mlinica spring), i-3 (jamina – periodic spring), i-4 (spring in the lopar cove), i-5 (ciganka spring), i-6 (jerko water spring – jerkovac), i-7 (vrutak water intake and pumping station), i-8 (civi – spring and water intake), i-9 (plimica – water intake), i-10 (podgabar – water intake) and i-11 (spring in the podšilo cove). the stolac cove and ciganka spring had no water while the fieldwork was conducted, which is probably the result of the summer dry season. the vrutak, mlinica, ciganka and jer kovac springs (figure 6) were previously utilised for the pub lic water supply. recently however, their use has been discontinued due to an increase in the concentration of sodium chloride. measurements of the basic physico – chemical characteristics of spring waters were carried out in september 2008. the air temperature during the measurement period ranged from 23–25 °c. water temperatures at the source are in the range of 14.6 °c (jerkovac) to 21.1 °c (lopar cove). electrolytic conductivity is in the range of 610 μs/cm (jamina) to 2.55 ms/cm (mlinica), and total dissolved solids from 423 mg (jamina) to 1785 mg / l (mlinica). the water is clear, colourless and odourless in all of the springs. springs with in creased mineralization have a salty taste, which probably comes from dissolved sodium chloride. 4. thermal characteristics of rock samples the thermal characteristics of rocks were measured in order to determine their ability to conduct and accumulate heat. typical samples from the study area were collected in open and stratigraphically well-defined outcrops. in addition, upper cretaceous carbonates were sampled from a fresh road cut that runs perpendicular to the direction of the rab anticline (figure 1). the main lithological description of the sam ples is given in table 1. laboratory studies were conducted in the cgs laboratory. the intention was to analyse 15 samples of rock from table 1: statistical analysis of the results of thermal parameters measurement (λ (k) – coefficient of thermal conductivity, cρ – volumetric heat capacity, a – thermal diffusivity, min.lowest measured value, max. highest measured value, mean – mean value of a thermal parameter) sample name sample description geothermal parameters l (k) (wm–1k–1) cr (jm–3k–1) (x106) a (m2s–1) min. max. mean min. max. mean min. max. mean l -1 crystalline limestone 3.18 3.31 3.26 2.17 2.41 2.31 1.37 1.57 1.44 l -2 crystalline limestone 3.19 3.34 3.27 2.08 2.38 2.25 1.36 1.53 1.45 l -3 crystalline limestone 3.00 3.21 3.09 2.35 2.77 2.6 1.16 1.25 1.2 l -4 crystalline limestone 3.17 3.34 3.28 2.07 2.44 2.32 1.37 1.58 1.44 l -5 yellowish – grey limestone 3.46 3.55 3.50 2.76 2.97 2.88 1.18 1.23 1.20 l –5a yellowish – grey limestone 3.21 3.28 3.24 2.66 2.70 2.68 1.20 1.22 1.21 l –6 brownish – grey limestone 2.70 3.38 3.03 1.81 2.78 2.16 1.23 1.51 1.35 l –7 white limestone 3.23 3.29 3.26 2.67 2.79 2.72 1.19 1.22 1.21 l-8 coarse – grained sandstone 3.95 4.79 4.26 2.29 2.95 2.79 1.44 1.73 1.53 l-9 coarse – grained sandstone 3.82 3.91 3.85 2.66 2.82 2.74 1.35 1.46 1.39 l-10 nummulite calcarenite 3.42 3.69 3.56 2.12 2.60 2.37 1.72 1.42 1.50 l-11 slightly sandy marl 1.52 1.77 1.61 1.64 1.85 1.71 0.83 0.87 0.85 l-12 light grey limestone 3.00 3.33 3.14 2.42 2.87 2.71 1.13 1.17 1.15 l-13 light grey limestone 3.21 3.36 3.30 2.07 2.38 2.25 1.33 1.53 1.44 l-14 limestone breccia 3.32 3.42 3.35 2.93 2.97 2.94 1.13 1.17 1.15 l-15 limestone breccia 3.24 3.46 3.34 2.92 2.96 2.82 1.11 1.15 1.13 l-16 foraminiferal limestone 3.59 3.83 3.68 2.72 2.78 2.75 1.31 1.35 1.32 l-17 light grey limestone 3.24 3.44 3.41 2.09 2.38 2.25 1.33 1.51 1.43 l-18 foraminiferal limestone 3.29 3.56 3.37 2.38 2.49 2.45 1.32 1.50 1.40 l-19 grey and yellowish marl 1.42 1.61 1.53 1.65 1.88 1.73 0.81 0.87 0.84 l-20 yellowish sandstone 2.58 2.78 2.68 1.87 2.05 1.96 1.34 1.37 1.35 geologia croatica 66/1geologia croatica 34 the study area, however, due to the diversity of the lithostratigraphic units, 21 samples were analysed. this ensured that good quality and representative data on the thermal characteristics of the rocks was obtained. after preparation (cutting, polishing) measurements were carried out, including: coefficient of thermal conductivity (λ), volumetric heat capacity (cρ) and thermal diffusivity (a) of the rock samples. measurements were carried out using a non-stationary (quick thermal conductivity method) (sumikawa & arakawa, 1976; prelovšek & uran, 1984) instrument isomet 2104 (applied precision ltd.). according to the manufacturer, the measurement accuracy is 10% for thermal conductivity and 15% for volume heat capacity 15%. the number of measurements per sample was 8–10, totalling 190 measurements of thermal parameters. average values of the coefficient of thermal conductivity, volumetric heat capacity and thermal diffusivity of the samples were obtained from multiple measurements with displacement of sensors and statistical analyses. to obtain the thermal characteristics of samples equal to those in situ, the samples were immersed in water for 20 days. according to previously conducted measurements saturating the porous rock increases the thermal conductivity by up to 33% (kovačić, 2007). it is assumed that the rocks at depths greater than 50 m from the surface are mostly saturated with water. this assumption is supported by the existence of water in the jamina cave and a number of periodic and permanent springs in the study area. the rocks below sea level are saturated throughout the year. the results of thermal parameter measurement were statistically analysed and summarised in table 1. sampling locations are indicated on the map (figure 5) (sampling locations on goli island not included on the map). 5. thermal characteristics of stratigraphic units the thermal characteristics of stratigraphic units were calculated by statistical analysis of mean parameter values of samples that are typical for individual units. the aim of the calculation was to establish whether the stratigraphic and lithologic units are able to conduct and accumulate heat. thermal characteristics of the quaternary sediments were not measured, but estimated. upper cretaceous carbonates upper cretaceous sediments cover a large portion of the investigated area, have a great thickness and different facies features, requiring a greater number of samples to describe this unit than others. table 2 shows mean values of their thermal parameters and in table 3 these values are statistically processed to obtain the mean values of thermal parameters for upper cretaceous stratigraphic units. tertiary (lower and middle eocene) foraminiferal limestone foraminiferal limestones make up a small portion of the research area. they are lithologically similar to the underlying upper cretaceous. therefore, only two samples were taken for analysis. the results of the measurements are shown in table 4 and the mean thermal parameter values in table 5. tertiary (middle and upper eocene) flysch deposits tertiary flysch deposits are very diverse in terms of lithology and facies. samples were collected from the characteristic lithological components, with the number of samples in proportion with their representation in the field (table 6). mean values of the stratigraphic unit thermal parameters are shown in table 7. table 2: mean values of the thermal parameters of rock samples of upper cretaceous age (λ (k) – coefficient of thermal conductivity. cρ – volumetric heat capacity, a thermal diffusivity) sample name l (k) (wm–1k–1) cρ (jm–3k–1) (x106) a (m2s–1) l 1 3.26 2.31 1.44 l 2 3.27 2.25 1.45 l 3 3.09 2.60 1.20 l 4 3.28 2.32 1.44 l 5 3.50 2.88 1.20 l – 5a 3.24 2.68 1.21 l 6 3.03 2.16 1.35 l 7 3.26 2.72 1.21 l 12 3.14 2.71 1.15 l 13 3.30 2.25 1.44 l 14 3.35 2.94 1.15 l 15 3.34 2.82 1.13 l 17 3.41 2.25 1.43 table 3: thermal parameters calculation for upper cretaceous stratigraphic unit (λ (k) – coefficient of thermal conductivity, cρ – volumetric heat capacity, a thermal diffusivity) parameter minimum maximum range mean unit λ (k) 3.03 3.50 0.47 3.27 (wm-1k-1) cρ 2.16 2.94 0.78 2.53 (jm-3k-1) (x106) a 1.13 1.45 0.32 1.29 (m2s-1) miron kovačić: geothermal properties of the northern part of the island of rab geologia croatica 35 thermal features of quaternary rocks were not specifically investigated because of their low occurrence in the research area. according zoth & haenel (1988), the thermal conductivity of sand ranges from 0.2 to 2.48 wm–1k–1, however kovačić (2007) suggests that the type of sand in lopar has a coefficient of thermal conductivity of around 1 wm–1k–1. 6. discussion of research results and the possibilities of geothermal energy utilization in the study area there are a number of natural springs in the study area, some of which are permanent, while others are periodic and active only during the spring, winter and late autumn. the previously strong ciganka spring, which was once used for public water supply, dried up completely. the content of total dissolved solids in water (tds) detected by the field measurements indicates increased mineralization. according to geological and balneological criteria (iveković & peroš, 1981), the mlinica, plimica, and podgabar springs, together with those in the lopar and podšilo coves, can be considered as mineral waters because they contain more than 1 g/l of dissolved solids. the civi and jerkovac springs, containing 960 and 940 mg/l total dissolved solids respectively, are also close to the lower limit for mineral waters. since chemical analysis of water from mlinica shows that sodium chloride is the dominant dissolved solid, and all waters with elevated mineralization have a salty taste, it can be argued that the increased mineralization of these waters is caused by sea water mixing. accordingly, one can expect that the water chemistry changes during the year, depending on the amount of rainfall and seawater intrusion. spring water temperatures are slightly higher than the annual mean temperature of the area, which is most likely caused by seepage through the summer due to a warmed rock mass and the fact that intake structures have been built on some of the springs. intake structures retain the water at shallow depths below the surtable 5: thermal parameters calculation for lower and middle eocene stratigraphic unit (λ (k) – coefficient of thermal conductivity, cρ – volumetric heat capacity, a thermal diffusivity) thermal parameter minimum maximum range mean unit l (k) 3.37 3.68 0.31 3.52 (wm-1k-1) cρ 2.45 2.75 0.30 2.6 (jm-3k-1) (x106) a 1.32 1.4 0.08 1.36 (m2s-1) table 6: mean values of the thermal parameters of rock samples of middle and upper eocene age (λ (k) – coefficient of thermal conductivity, cρ – volumetric heat capacity, a thermal diffusivity) sample name l (k) (wm–1k–1) cρ (jm–3k–1) (x106) a (m2s–1) l-8 4.26 2.79 1.53 l-9 3.85 2.74 1.39 l-20 2.68 1.96 1.35 l-10 3.56 2.37 1.5 l-11 1.61 1.71 0.85 l-19 1.53 1.73 0.84 table 7: thermal parameters calculation for middle and upper eocene stratigraphic unit (λ (k) – coefficient of thermal conductivity, cρ – volumetric heat capacity, a thermal diffusivity) parameter minimum maximum range mean unit l (k) 1.53 4.26 2.73 2.91 (wm–1k–1) cρ 1.71 2.79 1.08 2.21 (jm–3k–1) (x106) a 0.84 1.53 0.69 1.24 (m2s–1) table 4: mean values of the thermal parameters of rock samples of lower and middle eocene age (λ (k) – coefficient of thermal conductivity, cρ – volumetric heat capacity, a thermal diffusivity) sample name l (k) (wm–1k–1) cρ (jm–3k–1) (x106) a (m2s–1) l 16 3.68 2.75 1.32 l 18 3.37 2.45 1.4 geologia croatica 66/1geologia croatica 36 face where it warms up. in order to accurately determine the natural regime and spring water temperatures, multiple measurements during different seasons would be required. based on the chemistry and temperature of spring waters, it can be argued that they do not originate from deep aquifers. the measurements indicate that the ranges of values of the coefficient of thermal conductivity of all rock samples are relatively small at around 10%, with the exception of three samples. the ranges of the volumetric heat capacity and thermal diffusivity are slightly higher, which is usual for this type of measurement. given these test results, it can be concluded that almost all the sampled rocks in the research area are thermally homogeneous. mean values of thermal conductivity of the upper cretaceous carbonate rock samples are very uniform and are in a relatively small range. given this, it can be argued that the upper cretaceous stratigraphic units are thermally homogeneous. in a geothermal context, this unit can also include the foraminiferal limestones. such a geothermal unit, taking into account stress deformation and the locally karstified carbonate subsurface, has a coefficient of thermal conductivity of 2.7 to 3.3 wm–1k–1. the mean volumetric heat capacity is 2.53 ´ 106 jm–3k–1 , and the thermal diffusivity 1.29 m2s–1. actual values are certainly a little lower because of the reasons mentioned above. all things considered, the upper cretaceous carbonates and tertiary foraminiferal limestones have relatively good thermal properties to conduct and accumu late heat. unlike the carbonate sediments, the tertiary flysch deposits are lithologically diverse. accordingly, the unit is thermal ly inhomogeneous. the highest average value of the coefficient of thermal conductivity is observed in sandstone, at about 3.6 wm–1k–1. however, the sandstones have very different thermal conductivities ranging from 2.68 to 4.26 wm–1k–1. the mean value of their volumetric heat capacity is 2.5 ́ 106 jm–3k–1, and the thermal diffusivity of 1.42 m2s–1. the geothermal parameter values of calcrudites are similar to those for sandstone. the average value of thermal conductivity of the marl is only half the value of the sandstone at 1.57 wm–1k–1. accordingly, the average values of their volumetric heat capacity of 1.72 ´ 106 jm–3k–1 and thermal diffusivity 0.84 m2s–1 are also low. the mean coefficient of thermal conductivity of the tertiary flysch sediments is 2.91 wm–1k–1, with a volumetric heat capacity of 2.21 ´ 106 jm–3k–1 and a thermal diffusivity of 1.24 m2s–1. the results indicate that the tertiary flysch sediments are a thermally highly inhomogeneous unit, suggesting that the average value of its thermal characteristics is only an approximation, and the actual values can vary greatly from place to place, from a good to poor ability to conduct and accumulate heat. quaternary deposits, largely composed of sands, are characterized by their poor ability to conduct and store heat. there is no published information on the deep boreholes in the coastal area, which is why the temperature reports at depth can only be deduced from the map of geothermal gradients and from the temperatures prevailing at 2000 m depth (jelić et al., 1995). according to the aforementioned data, the geothermal gradient in this area is about 0.015 °c/m. this is below the average geothermal gradient for the most part croatia due to the effect of thickening of the earth’s crust in the coastal area of croatia where the moho discontinuity is extended to depths of 32 to 43 km (aljinović, 1986). according to data from the meteorological and hydrological services of croatia, the mean annual temperature in the investigated area is about 14 °c (zaninović et al., 2004). from the geothermal gradients and mean annual air temperature, it is possible to estimate the temperature of formations at depth from about 21.5 °c at 500 m, about 29 °c at 1000 m, and about 45 °c at 2000 m. given these calculations, the temperature suitable for use in balneological and recreational purposes occurs at depths greater than 1500 m, and the temperature of groundwater that would be suitable for the production of heat is at depths below 2000 m. judging by the broader geological frame, no rocks with primary (intergranular) porosity should occur at these depths. this conclusion is supported by the fact that the waters of investigated natural springs have both a chemistry and temperature consistent with a shallow aquifer origin, possibly from karstified limestones and tertiary sandstones acting as aquifers at such depths. therefore, at depths with high enough temperatures, no aquifers suitable for the exploitation of geothermal water can be expected. given the good coefficient of thermal conductivity and volumetric heat capacity, upper cretaceous and tertiary limestones could be used during the summer to store excess heat while cooling the closed space by heat pump. during the winter, energy stored in this manner could be used to heat up the indoor space or water (hendriks et al., 2008). this kind of renewable energy could be used to a lesser extent in some locations of tertiary flysch sediments. without additional research to establish the porosity and permeability of the aforementioned sedimentary complex it is impossible to estimate which energy storing system could be utilized. limestones are without primary porosity while the secondary porosity caused by karstification can be vary with location rendering decisions related to energy consumption only possible after constructing new investigation boreholes at the proposed locations. where porosity and permeability of the rocks is favourable, the open system could be used – aquifer thermal energy storage (ates) – which utilizes water circulation in the aquifer for the purpose of the transfer and storage of heat. considering the good thermal conductivity and capacity of these rocks, the closed system – borehole thermal energy storage (btes) – using rocks and underground water for energy storage would be certainly rewarding. 7. conclusions temperatures of the studied natural spring waters were slightly higher than the mean annual air temperature which most likely reflects the time of the study (early autumn/fall). increased mineralization of the water in some springs is caused by the hydraulic connection with the sea. therefore, water chemistry and temperature of investigated springs indicate that they do not originate from deeper aquifers. miron kovačić: geothermal properties of the northern part of the island of rab geologia croatica 37 almost all sampled rocks are thermally homogeneous, with their coefficient of thermal conductivity varying in range of about 5% below or above the measured value. upper cretaceous carbonates and tertiary foraminiferal sediments are thermally homogeneous and have relatively good thermal properties to conduct and accumulate heat. tertiary flysch deposits are lithologically and thermally highly inhomogeneous, so the average values of their thermal parameters can only serve as approximate values, while the actual values of thermal parameters can greatly vary from one location to another. given the available information and calculations, a temperature of about 21.5 °c can be expected for the formation at a depth of 500 m. at a depth of 1000 m the formation temperature is about 29 °c and at 2000 m about 45 °c. given these formation temperatures, the small possibility for rocks with primary porosity to be found at depths with adequate temperatures, and the high costs of deep drilling, it is suggested that the use of deep geothermal energy would not be profitable in the investigated area. alternatively, it is possible to use geothermal energy from shallow boreholes in places where upper cretaceous and tertiary carbonate sediments with favourable thermal characteristics occur. these deposits would serve as heat accumulators. in the warm part of the year heat pumps would be used to transfer excess heat from the buildings into the ground (air conditioning), and during the cold part of the year the stored heat would be pumped back into the buildings (heating). in order to define the thermal energy storing system (ates or btes) investigative boreholes must be constructed and the porosity and permeability of the rocks be determined. references aljinović, b. (1986): karta debljina mohorovičićeva diskontinuiteta na području jugoslavije [depth of the mohorovičić discontinuity in the yugoslav region – in croatian].– nafta, 37, 127–130. hendriks, m., snijders, a. & boido, n. (2008): underground thermal energy storage for efficient heating and cooling of buildings.– in: hassan, t. & ye, j. (eds.): “1st international conference on industrialised, integrated, intelligent construction, loughborough, may 14–16, 2008, 315–324. iveković, h. & peroš, r. (1981): mineralne i termalne vode sr hrvatske [mineral and thermal waters of sr croatian – in croatian].– jazu, zagreb, 190 p. jelić, k., kevrić, i. & krasić, o. (1995): temperature i toplinski tok u tlu hrvatske [temperature and heat flux in the croatian territory – in croatian].– in: vlahović, i., velić, i. & šparica, m. (eds): 1st croatian geological congress, opatija, october 18– 21, 1995., proceedings 1, zagreb, 245–249. jelić, k., kovačić, m. & košćak-kolin, s. (2005): state of the art of geothermal resources in croatia in the year 2004.– in: horne, r., stacey, r., juliusson, e., villaluz, a., chen, c-y., dastan, a., li, k., garner, l., bolds, j. & polyakova, j. (eds.): world geothermal congress 2005th, april 24–29, 2005, antalya, turkey, 588–596. kovačić, m. (2001): temeljne geotermijske značajke hrvatske i korištenje geotermalnih voda u hrvatskoj tijekom 2000. godine [basic geothermal characteristics of croatia and use of geothermal water in croatia in 2000 – in croatian].– hrvatske vode, 35, 145–150. kovačić, m. (2007): odnosi toplinske provodljivosti stratigrafskih jedinica iz šireg područja zagreba [relations between the thermal conductivity of the stratigraphic units in the wider area of zagreb – in croatian].– rudarsko-geološko-naftni zbornik, 19, 27–33. mamuzić, p. & milan, a. (1969): osnovna geološka karta sfrj 1:100000, list rab l33-114 [basic geological map of sfry 1:100000, rab sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. mamuzić, p. & milan, a. (1973): osnovna geološka karta sfrj 1:100000, tumač za list rab l33-114 [basic geological map of sfry 1:100.000, geology of the rab sheet – in croatian].– geološki zavod zagreb, savezni geološki zavod beograd, 39 p. marinčić, s. (2009): flišne naslage (srednji i donji eocen) [flysch deposits (middle and lower eocene) – in croatian].– in: velić, i. & vlahović, i. (eds.): tumač geološke karte republike hrvatske 1:300.000. croatian geological survey, 77–79. marjanac, t. & marjanac, lj. (2007): sequence stratigraphy of eocene incised valley clastics and associated sediments, island of rab, northern adriatic sea, croatia.– facies, 53/4, 493–508. doi: 10.1007/s10347-007-0120-6 prelovšek, p. & uran, b. (1984): generalised hot wire method for thermal conductivity measurements.– j. phys. e. sci. instrum., 17, 674–677. rajver, d. & ravnik, d. (2002): geotermična slika slovenije – razširjena baza podatkov in izboljšane geotermične karte [geothermal picture slovenia-extended database and enhanced geothermal maps – in slovenian].– geologija, 45, 519–524. ravnik, d., rajver, d., poljak, m. & živčić, m. (1995): overview of the geothermal field of slovenia in the area between the alps, the dinarides and the panonian basin.– tectonophysics, 250, 135–149. sumikawa, s. & arakawa, y. (1976): quick thermal conductivity meter.– instrumentation and automation (japan), 4, 60–68. zaninović, k., srnec, l. & perčec tadić, m. (2004): digitalna godišnja temperaturna karta hrvatske [a digital annual temperature map of croatia – in croatian].– hrvatski meteorološki časopis, 39, 51–58. zoth, g. & haenel, r. (1988): thermal conductivity.– in: haenel, r., rybach, l. & stegena, l. (eds.): handbook of terrestrial heat-flow density determination, kluwer academic publishers, dordrecht/boston/london, 449–467. manuscript received february 20, 2012 revised manuscript accepted january 14, 2013 available online february 28, 2013 geologia croatica 66/1geologia croatica 38 geol. croat. 50/2 1 165-171 1 zagreb 1997 povijest paleobotanickih istrazivanja u hrvatskoj enio jungwirth kljnene rijeci: paleobolanika. povijesni pregled. j-irvalska. sazetak ovim clankom autor jc ukratko dao prcgled paleobotanickih istrazivanja makroflorc na tlu hrvatske, pri tome se posluzivsi llsporedivanjem sa povijescu razvitka paleobotanike kao znanstvene discipline na tlu europe. dotaknuvs i se ie problematike upozorio j e na zapostav ljenost takvoga vida znanslvcnog islrazivanja u hrvatskoj, ali i na ranije rezultale. pa leobotanika (pal eofitologija, fitopaieontoiogija , palconlologija bilja) je razmjerno mlada znanost. koja rabcci botanicke i geoioske met ode pomaze pri rekon­ st ruiranju zivotnc srcdinc odrcdenoga prostora u odre­ denom geoioskom vrcmcnu. osnivac modcrnc pajco­ bolanike jc a. brongniarl (1801 -1876). znacaj paleo­ botanike ocituje se u lome sto proucava sacuvane biljne ostalke (najcesee vegetativne i rasplodne organe lisee, grancice, plodovc, cesere, pelud, spore i rjede petrifici­ rana stabla) koji su zapravo neznatni dio nekadasnjeg biljnog sv ijeta, a sada ocuvanog u sedimenlima razlicite starost i. rabeei rezultate paleobotanickih istrazivanja dolazi se do podalaka koji pomazu u osvjetljivanju problema razvitka (evolucije) biljnog svijeta, ij. filo ­ gcnijc. na paleobotanickim rezultatima izvedeno filo ­ genctsko slabl0 predstavija temelj moderne biljne sis­ tematikc. proucavanjcm vanjske i unutarnje grade fosil­ nih biljaka dolazi se do znacajnih rezultata u morfo­ geniji nizih, a posebice vis ih (u smislu organiziranosti) biljaka. odredbom pojedinih vrsta iii rodova, te odre­ divanjcm biljne zajcdnice u odredenom geoloskom raz­ doblju (reperna flora iii "fixed flora") mozemo dati zna­ cajni doprinos znanostima poput biljne geografije, pale­ oklimaloiogije i pajeogeografijc. u novije vi'ijeme elva su se autora prihvatila pregle­ da povijcsti razv itka paleobotanike na "starom konti­ nentu", sio ec u ovomc radll poslllziti za usporedbu u svczi paleobotanickih istrazivanja na tlu hrvatske. ui. ljudevita gaja 2b, hr \oooo zagreb, croatia. key words: palaeobotany, historical review. cro­ atia. abstract thi s paper is concerned by comparison of palaeobotanical studies of macroflora in croatia with those ones in europe, as well by recent­ ly neglect of fossil macroflora in croatia. prvi od njih, obrhel (1980, 1984). analizira raz­ vojne ctape na primj eru "ccskc skolc" koja jc imala snazan znanstveni uticaj, pa razlikuje: 1. predznanstveni period (1775 -1820) s fundamen ­ talnim paieobotanickim promatranjima i prvim paleo­ botanickim radovima, npr. " lilhophylacium bornia­ num" (born. 1775); 2. poeetke znanstvene paleobotanike (1820-1833). tj. 1820. se smatra pocetnom tockom pal eobotani ckc nomenklaturc, a razdoblje do 1833. godi ne vremenom razvitka paleobotanickih metoda, podrijetla klasifikacije fosilnoga bilja i osnutka stratigrafske paicobotanike. glavni pccat toga vrcmcna dalo je izdavanje 1. sveska "versuch einer geognoslisch-botanischen derstellung der flora der vorwelt" (sternberg. 1820); 3. klasicnn znanstvenu paleobotanikn (18331849) kao period koji zapocinje izdavanjem 5. i 6. sternbergova sveska u koautorstvu s preslom i cordorn (sternberg. 1833); 4. slijcdi pad ccskc palcobolanike (1849-1870); 5.od 1870. do 1918. je period oiivljavanja paleo­ bolanike (slur, velinovsky. krejci . stoklas). potom gla­ vnu ulogu u obradivanju palcoflorc ceske preuzimaju nijemci (euingshausen. engelhardt. i-i. potonie). najsvjciiji izvori podalaka (prema mal, 1995) u svezi razvi tka paleobotanickih istrazi vanja, izvedeni iskljucivo na primjeru istrazivanja tcrcijarnih biljaka, this paper was presented at the scientific meeting dedicated to the 80th anniversary of the life of professor milan herak, held on march 5th, 1997 in zagreb 166 omogucuju izdvajanje nekoliko crapa (temcijni kriterij su pisani radovi): 1. predznanstveno razdoblje (1709-1819) tu se sllsrecemo s nckoliko istaknutih imena kao 5to su: sch­ euchzer (1672-1733), knorr (1705-1761), linne (17071779), andreae (1724-1793), walch (1725-1778), sch­ lotheim (1765-1832), endlieher (1804-1849), te s jos ilckima. 2. "herojsko" razdoblje (1820-1880) prvo ime paleobotanickc znanosti svakako je vee spomenuti sch­ iolhcim, a potoin s lijedi plejada znanih nam imena: sternberg ( 1761-1838), presl (1794-1852), brongniart (1801-1876) , gepperl (1800-1884), unger (18001870) , ai. braun (1805 1877), corda (1809 -1839), heer (1809-1883) , sismonda (1815-1870), schenk ( 18 15189 i) , saporta (1823 1895), ettingshausen (18261897), krasan (1840-1907), te jos mnogi koje bi vrijcdilo spomenuli , a ne smijcmo zaboraviti niti naseg vi siani -a ( 1800-1868) 0 komc je pisala kochan­ sky-devlde (1981). 3. razdoblje stagnacije (1881 1906) prvo valja istaknuti bolanickc radove engjera (1844-1930), "stara" poznata imcna kao 5to su stur (18271893), engelhardt ( 18391918), velinovsky (1858-1949), pilar (18461893), ali i to da un aloe stagnaciji gotovo u svim europ­ skim zemljama rade paieobotanicari. istaknimo imena kao sto su npr. baily (18 19-1888) , gardner (18441930), marion (1846-1900), wlirtemberger (l8361903), beck (1858-1919), c. reid (1853-1916), schm­ allhallsen (1849-1894) i dr. 4. razdoblje suvremenog nacina rada (19071942) to je razdoblje velikog znanstvenog napretka (dvaclesele godine ovoga stoljeca) u paleokarpologiji, allatomiji drvela, proucavallju slanicja plod ova i sje­ menja, palcoklimatologiji itd. redaju se brojna istaknu­ ta imcna: e.m. re id (1860-1953) , chandler (18971983), kichhcimcr (1911-1984) , nikitin (1890-1950), palibin (1872 1949) , gothan (1879-1954), krallse l (18901966), kryslofovich (1885 -1953), jurasky (1903 neslao 1945), seward (1863-1941), h. poloni" (18571913), r. poloni" (1889-1974), thicgard (1905-1977), thomson (1891 -1957), weyland (1888-1974), edwards (1890-1956), nomcjc (1901 -1976) itd. 5. razdoblje "renesanse" paleobotanickih istra­ zivanja (od 1947) uz poznata imena r. potoniea, gothana , weylanda, nemejea, kirehheimera, thom­ sona , susrecemo brojna druga imcna: m~igde[rau ( 1907), andreanszky (1895-1967), kolakovsky (1906), dororccv (191 1-1985), mai, knobloch, buick, kvaeck, itd . u hrvatskoj na jednaki nacin, ali s potpuno razlicitim kvantitativnim sudjelovanjem istrazivaca, jer vecina nisu bili paleobolanicari, mozemo razlikovati nckc clapc proucavanja paleoflore kojc se podudaraju s prelhodno spomcnutim razciobljima (u smislu mal, 1995). prcskociti mozemo prcdznanstvcno razdoblje, te se ncposredno ukljuciti u tijekove paleobotanickih ueologla lroatlc<l )u/l istrazivanja na nasel11 tlu od sredine 19. stoljeca, dakle il11amo: 1. "herojsko razdoblje" (1838-1900) premda razmjerno dugotrajno razdoblje, s pravol11 ga mozemo tako nazvati, jer obuhvaca i znamenita imena toga doba, od kojih su neki radovi s nasih tcrena zapravo poceci njihova uspjesna rada. na prvol11 mjes\u svaka­ ko je unger koji u nekoliko navrata pise 0 fosilnoj t10ri radoboja (unger, 1838, 1840, 1850,1868, 1869). zatim slijedi gappen koji je obavio prvc analize peluda iz matcrijala dobivenog iz radoboja (goppert, 1841), a fosilne kukce toga lokaliteta obraduje znani bot ani car i entomolog heel premcia nije paleobotanicar vrijedno je spomenuti i l. blich-a, s obzirom lia prvi navodi fosilnll noru planine promine (buci-i, 1851, sir. 686). slijcdi ime hrvatskog lijecnika i bolanicara r. visiani-a, te njegov rad "piante fossili della dalmazia" (visiani, 1858), u kome se obradujc fosilna flora pla­ nine promine. paleofloru radoboja (pa i insekte) i pla­ nine prominc obraduje jos ettingshausen, tako cia pos­ toji i vise pisanih radova (eti1ngshausen, 1850a, b, c , d, 1851, 1853 , 1854, 1855, 1870,1871 , 1896). geinitz (1868) ukratko pise 0 fosilima biljnoga pod­ rijetla trgovske gore, kao i stur (1868) koji govori 0 biljnim ostacima rada sigillaria, a potoill pise i 0 fosil ­ noj flori pronadcnoj kod vrdnika u srijemu (stull., 1872). prvo paleobotanicko djelo na hrvatskom jcziku je djelo "0 petrefaktih (okaminah) 1i obce i 0 podzem­ noj fauni i flori susedskih laporah" koje je napisao vukotinovic (1870), hrvatski knjizevnik, politicar i prirodoslovac. od njcga potjecll jos neki radovi (vukotinovic, 1875a, b, 1876, 1878).0 ostacima pretezito porodicc taxodiaceae, ie ostaeima vrste myri­ ca iignillll11 (unger) saporta oloka paga pise i radimsky (1877). slijedi vcliki rad 0 zbirci fosilne flare sv. nedjcljc, sliseda i dolja koju su prikupili gor­ janovic-kramberger i pilar, a obradu materijala je ciao pilar (1883), doi'im gorjanovic-kramber­ ger (1894) 0 tome pise ponovno i tck taksalivno nabraja biljne vrste. slijcdi nckoliko radova u svezi lokaliteta podvin ii siavoniji , a au lor je engelha­ rdt (1884, 1885, 1890, 1893), koji se poscbice islak­ nuo u obradi pajeollore susjedne bosne. ward (1889) pisllci 0 geografskom rasporedu fosilnih biljaka spo­ minje i dalmaciju, hrvatsku i slavoniju (od sir. 718). kerner (1896) obraduje hednu floru otoka i3raea, a radi se 0 zbirci cetinjaca (najpoznatija vrsta cunning­ hamia elegans corda), paprati i dvosupnicama sup­ tropskih osobina. konaeno, faidiga (1898) spominje tlom radoboja. 2. "razdoblje predstagnacije" (1902-1945) prc­ mda nije paleobotanicar, kerner sc pojavljuje nizom clanaka 0 nalazima fos ilne flore. govori 0 tereijarnim j starokvartarnim biljkama sinjskoga polja i dalmacijc (kerner, 1902, 1905, 1906, 1907a, 1916), trijaskim biljkama svilaje (kerner, 1907b) i karbona velcbita (kerner, 1910). i nas veliki botanicar adamovic (1905) govori 0 razvitku flore na balkanu od icrcijara, jungwinh: povij~l p;l leobolmlickih i:'lrai:ivanja u 1-lrv:ll!>koj docim forenbacher ( 1910) pise 0 razvitku tere i­ jarnc norc ii europi do rccentnih vrsta. sc hubert (1909) u "gcologiji da lmacijc" na nekoliko mjcsta spo­ minje flam irijasa svi lajc, krede hvara, coeena "pra­ mi nskih naslaga", neogena okolinc sinja (autori od rc­ daba su vee ovdje spomcl1lui). no, govorcci 0 donjem coecnu (sir. 55) govo ri 0 "kozinskim naslagama" i napominje da u tim naslagama "nalazimo u dalmacij i osa bito mnogo bilj cvnih i zivot inj skih okam ina". sli­ jcdccih 20-lak goclina svclo se na pisanje par clanaka 0 bi ljkama. tako poljak ( 1912) pi se ookamenjenim sli mama, a horv at (! 928) 0 rasprostranjenju i pro­ s losti nomih c lcll1cnala sjevernc hrvatskc i siavonije. tek edwards (1932) pi se 0 donjoeoeenskim biljka­ m" ist re, cernjj\ vsk i (1933) 0 plioeenskoj flori glo­ govea ii siavoniji, a cubrilovic ( 1933) se pisuci 0 icrcij aru jz dijc la zagrebackc gore osvree i na nalaz ccscra vrslc pillu s cf. ovi!ormis endlicher prona­ cl ellog u ccmcnlni m laporima pocl suseda. boros (1933) opisujc fosi lni plod roda ceitis iz porod icc bri ­ jcsla (proucavanjc plodova uz sjemcnjc jc vrlo vazno u pal eobolanick ill1 islraz ivanjim a op. au l). cernja­ vski & klrill n ( 1934) se javljaju i' lankom 0 [jori posl\crcijarnih slojeva savskc doline kod siska. polic ( 1935) pise 0 oligoeenu i !lori toga doba kod sela plani­ na na zagrcbackoj gori. poznati ccski bolanicar i pale­ on tol og nemejc (1936) claj e prilog poznavanju kar­ bonske f10rc ugljonosnih naslaga sjcveroistocnog vc1ebi ta. horvat (1939) dajc kralki prilog 0 pozna­ vanj ll ireset ista 1i hrvatskoj11 zagorju, a jenko ( 1944) spominje ostatkc karbonske nare okolinc samobora. 3. " razdoblje stagnacije" ( 1945 danas) u ovo­ me izllzetno dllgo ill razdoblju napisani sli rijetki cianci koj i bi sc ticali palcorjorc, a jos rjecli koji ma jc to jedina lema. stoga vee l1 a pocctku mozemo istaknuti ave radovc: cernja vsk i (1 949) govori 0 borovoj11 cese­ ru iz suscda; anic ( 1959) govori 0 osob itosti f lora i klimc tereijara na podrlli'ju fnrj ; brk ic et al. (1974) na temelju makrorlore utvrcluju da slabomctamorfozi­ r31l<l serija potoka rad lovec pripacla karbonu i vrsni dio pcrmu; kochansky -devide & bajraktare­ vic ( 1976) pi su 0 ostatku obicne smokve, tj . vrste ficus cf. carica linne u dolljosarmalskim naslagama i-irva tskc; zaga r-sa kac & sakac (1 987) pisu 0 nalazi ma fos iln ih lopoca vrste nymp/taea arelllllse brongniart u tcrcijarnim naslagama okolinc sinja. prij c toga pantic ( 1962), te pantic et a l. (1976) samo napominju cia postoje ostaci karbonskc makrodo­ re na vel e bitu i n 3 papuku te krcdc na hvaru. sinkovec & sa kac ( 1982) pisuci 0 paleogenskim boksi lima dalmacijc u svczi paleoreljefa kazu (s ir. 312) da jc izmodcli rall lijekom duzcg razdobjja konlinen­ (alne faze , pod li vjctima topic i vlazne tropske klill1c , a tv rclnju temclj e na oslacima palmi. poiotti navode lokalitet dujici (drnis) gdje u bazalnom dijclu "promin­ skih naslaga" pos\oje vapnellci s ostac ima kopncne makro[]ore, pa izmedu ostalog nabrajaj u (nijc jasno tko je odredivao vrslc) araiicarifes sternbergi goppert 167 (::: doliostl"obl/ s sternbergi goppert), el.lqllisefites erbrechii ettings hausen, sphellopteris eocellica ettings hausen. sl ii'nu !loru navode i na lokalitetu kru sevo (obrovae), gcljc sc pojavljuju jos i eilca/iplils oceallica unger , lallrlls pachyphylla ettings ha­ us en, dryalldra cf. broglliarti ettingsha usen i jos nekc vrste, a sedimenle smjestavaj ll u mocva rni okolis. slijedeci all tori clanka u kome sc navocli fosi lna !lora su susnjara & sakac ( 1988), gdje se op isuju mi occnski slatkovoclni sedij11cnti kod sinja. au tori isticu cia fosilni biljni matcrijal pripada vrstama ceraw­ phy/luni silljallu17l kerner = ceraloslraliotes sill­ janlls (kerner), taxodilllll distichili1l mioccllicif/ji heer, ctls/all ca kuhinyi koy ats , ci1l1l0mollliflll schcuchzcri heer (danas dapllllogcllc !jilinico (unger) knobloch et kv acek op. aul), te jos neke vrste kojc takodcr eitira i schubert ( 1909, str. [27) prema kerneru, a navocl e se i anali ze pel ucla (jov ic-erceg , neobjavljeno). mil-lajlovlc ( 1990) daje prcglcd paleogenskih fl ora jugoslav ijc, te posebiee pri tome istice njhovu osobitost (ovclje se to od nosi na tl oru rase, planine prom inc i susjednc zapadne l-leree­ gov ine). 0 rczuitatim::t pali noloskih istrazivanja postoji nekoliko radova: jovic-erceg ( 1960) daje rczu ltate palinoloskih is lrazivanja iignita lep avinc, slij cdi rad siki c & jovic (1969), draxler ( 1986) anali zira pelud ti vi ndiji kocl donje voce (sz hrvatska) . jeri ­ nic & jelen ( 1991 ) palinoloski obradllju busotinu kod otoka visa, spa nic et al. (199 1) lizorkc s otoka braca, bukovac cl al. ( l995) iznose izj11cdu ostalog i palinostraligrafsku intcrprctaciju trijasa 1z zum bcrka. l cdnako je potrebito naglas iti i paleobotanickll akti v­ nost t. derek i nj ezin o koaulorstvo tj raclu kovar ­ eder et al. ( 1995). konacno, postoji i nckoliko popu­ larnih clanaka koji se bave bilj kama iz zemljine pros10sli, ciji su au tori hoda k (1952), i-lor v at ic ( 1949, 1960), bajrakta rev ic (1992) i j ung­ wirth ( 1995). kako jc ovaj rad nap isan ii cast 80. obljctnice aka­ demika i-lcraka, njegovo je ime oslalo kao zakljucak, tj. nacinivsi presjek palcobotan ickih radova iii istraziva­ nja, ncminovno moramo ustvrditi , pa cak kolikogod kri ­ ticki (samokri ticki) bili raspolozeni, da uz pajcob­ otanicke radove r. visiania, g. pil ara, d. an ica i jos ncki h au lora, u i-irvatskoj ipak imamo i udzbcnik iz pal cobotanike ciji je au lor, nas slavljenik, prof. dr m. herak, a koji jc dozivio dva izdanja (her ak, 1953, 1963) . literatura adamovic, l. (1905): die entwicklung del' balkan­ nora seit der tertdi rzeit. engler's bolan ischen jahrbi.iehern, b. 36, h. 4, leipzig. an ic, d. (1959): karak ter /lora i klime icrc ij ara na podrucju fnrj.gcol. vjesnik, 12, 191 -204. lox bajraktareyic, z. (i992): yisokc sume geoloskc proslosti.trilobit, 8, 12-14, zagreb. born, i. (1775): lithophylacium bornianum seu index foss ilium, quae collegit, ct in classes ac ordi­ nes disposuil ignatius de born, ii.1-154, prague. boros, a. (i933): pliozane und pleistozanc celris­ fruchtc aus ungarn und dalmatien. foldt. koz­ lony, 63, 153-157, budapest. brkic, m., jamicic, d. & pantic, n. (1974): kar­ bonskc !laslage u papuku (sjevcroistoc na hrvats­ ka). geol. vjesnik, 27, 53-58. buch, l. (185 i): obcr die lagerung der braunkohlen in europa.bcrichtc akad. wiss. , 683-701, berlin. bukoy ac, j., grgasoyic, t., gloy acki-jer­ nej, z., jerinic, g., galoyic, i. & prto­ llan, b. (j995): litostratigrafska ra561amba dolomitnih naslaga trijasa jugozapadnog zumberka ll okviru radova na geoloskoj karli republike hrvatske 1:50.000.1. hrv. geol. kongr., zbornik radova, 1, 137-142, zagreb. cernjayski, p. (1933): prilog poznavanju f10re plio­ cena kad glogovca u hrvalskoj. vesn. geol. inst., 2, 179-186, beograd. cern.jayski , p. (1949): borova sisarka iz suseda. ­ gcol. anali balk. poluostr., 17, 159-169, beograd. cernjayski, p. & kirilln, g. (1934): 0 fiori organogcnih scdimcnata iz posttercijarnih slojeva savske dolinc kad siska .vesn. geo!. inst., 3/1, 186198, beograd. cubriloyic, v. (1933): tercijar jugozapadnog del a zagrebacke gore. ycsn. geo!. inst., 2, ij5-129, beograd. draxler, i. (1986): pollenanalytische untersuchun­ gen del' sediment pro ben aus der vindija hohle bci donja voca, nw croalien. rad jugos!. akad. znan. ullljctn., 424, 275 -287, zagreb. edw ards, w. n. (1932): lower eocene plants from istria. ann. mag. nat. hist., 10, 213 -216, buda­ pest. engelhardt, h. (1884): flora aus den unteren paludinenschichten des caplagrabcns bei podwin.­ abh. scnckenbcrg. nalurf. ges., 189-?, frankfurt/m. engelhardt, h. (1885): tertiarpflanzen aus dem graben von capla in slavonien. foldl kozlbny, 25, 217-261 , budapest. engelhardt, h. (1890): ober tertiarpfianzen aus dem graben capla in siavonien .verh. reichsanst., 17, 296 p., wien. engelhardt, h. (1893): flora aus den unteren paludinenschichtcn des capla-graben bei podvin (slavonien). yerh. geol. reichsanst., is, 359 p., wicn. ljc010g1<l lfoalica :lui" ettingshausen, c. (1850a): fossile flora von ra­ doboj.sitzungsber. akad. wiss., 5, 91-93, wien. ettingshausen, c. (1850b): bericht tiber unter­ suchung von fundorten tert iarer pflanzenresl im kaiserthume osterreich.lahrb. oeo!. reichsanst., j/4, 679-685, wien. ettingshausen, c. (1850c): sitzungen der k.k. geologischen reichsanstalt.lahrb. geo!. reich­ sanst., 1/2, 364-365, wien. ettingshausen, c. (1850cl): yerwahrung gegen prof. unger des sen hterarisches eigenthum an bear­ beitung der fossilen flora von radoboj nicht beein­ trlichtingt zu haben.sitzugsber. akad. \viss. , 5, 289-291, wien. ettingshausen, c. (185 1): flora von radoboj, parschlug und sotzka.haidingers berichtc, 143 p., wien. ettingshausen, c. (1853): ober die fossile c1es monic promina in dalmaticn.sitzungsber. akad. wiss., 10,424-429, wien. ettingshausen, c. (1854): nachtrag zur eodincn flora des montc promina (in dalmatien).sitzungs­ ber. akad. wiss. , math. nat. ci. , 12, 180-182, wien. ettingshausen, c. (1855): die eocane flora des monte promina (dalmatien). denkschr. akad. wiss., math. nat. ci., 8, 1-28, wien. ettingshausen, c. (1870): beitruger zur kennt­ niss dcr fossilcn flora von radoboj.sitzungsbci'. akad. wiss., math. nat. ci., 61/5, 829-906, wicn . ettingshausen, c. (1871): beitruge zui' kenntniss dec fossilcn flora von radoboj.verh. geo!. reich­ sanst., 2, 28 p., wien. ettingshausen, c. (1896): ober neue pflanzen­ fossilien in der radoboj-sammlung der univcrsilbit in llittich.sitzungsbcr. akacl. wiss., 473-500, wien. faidiga, a. (1898): ober pflanzenfossilien in der radoboj-sammlung.foldt. kozlony, 28 , 245, budapest. forenbacher, a. (1910): razvitak evropske f10re od tercijara do danas.olasnik. hrv. prii'. drustva, 22, 11-18, zagreb. geinitz, b. (1868): die fossilen pflanzenreste aus dem schiefergebirge von tergove in croalien. ­ yerh. geol. reichsanst., 8, 165-167, wien. goppert, h.r. (1841): ober das yorkommen von pollen in fossilem zaustande.n. jahrb. mineral., geol. etc. r. 1841 , 338-340, stuttgart. gorjanoyic-kramberger, d. (1894): geolo­ gija gore samoborske i zumberackc. rad jugos !. akad. znan. umjetn. , 120,1-82, zagreb. jllllgwirlh: povijcst palcobot~lllickih islfazivanja ii iirvmskoj herak , m. (1953): paleobotanika za geologe i biologe.skolska knjiga, zagreb, vll+ 160 p. herak, m. (1963): paleobotanika.skolska knjiga, zagreb, xl+ j 80 p. hodak, n. (1952): neobicne biljke iz proslosti zem­ lj e.mala nallcna knjiz. i-trv. prir. drustva, 82, 1-46, zagreb. i-iorvat, i. (1928): rasprostranjcnje i proslost medi­ teranskih, ilirskih i pontskih elemenata ii flori sjev­ erne hrvatske i slavonije. acta botaniea, 4, 34 p. , zagreb. horvat , j. (1939): prilog poznavanju cretova u hrvatskom zagorju. i-irv. geogr. g lasnik, 8-10, zagreb. horvath::, s. (1949): kadje nastalo cvijece?priro­ da, 36/3,65-70, zagreb. horv at](::, s. ( 1960): razvitak biljnog svijeta. ­ priroda, 47/ 1, 11 -26, zagreb. jenko, k. (j944): geo loski rad na listu samobor 1 :75.000. vjestnik t-trv. drz. geo!. zav . i hrv. drz. geol. muz., 2/3, 19-23 , zagreb. jerinic, o. & jelen, b. (1991): palynostratigraphy, depositional environment and climate of the upper triass ic in vlatka-1 off-shore well, west of vis island (a driati c sea).2nd intern. symp. on the adriatic carbonate platform, zadar (1991), abs ­ tracts, 130, zagreb. jovic-erceg, b. (1960): analiza spora i polena iz lignita lepavine.geo!. vjes nik, 13, 133 144, zagreb. jungw irth, e. (1995): maie ii se priroda obnoviti sama.priroda, 85, 26-27, zagreb. kerner v. merilaun, f. (1896): kreidepflanzen von lesina.jahrb. geo!. reichsanst., 45/1,37-58, wien. kerner v. merilaun, f. ( 1902): tertiiirpflanzen vom oslrende des sinjsko poljc in dalmatien.­ verh. geol. reichsans!. , 14/15,342-344, wien. kerner v. merilaun, f. (1 905): neogenpaanzen vom nord rande des sinjsko polje in mitteldalma­ tien.lahrb. geol. re ichsanst., 55, 593-612, wien. kerner v. merilaun, f. (1906): beitrage zur ken­ ntnis der fossilen flora von ruda in mitteldalma­ tien.verh. geol reichsanst. , 2, 68-70, wien. kerner v. merilaun, f. (1907a): vorliiufige mit­ teilung liber fui1(ie voil triasp flan zen in der svilaja planina.verh. geol. reichsans!., 12, 294-297, wien . kerner v. merilaun, f. (1907b): pflanzenreste aus dem iiltercn qllartar von sudund norddalma­ tien. verh. gcol. reichsans!., 14,333-339, wien. 169 kerner v. merilaun, f. (1910): uber einige neue erwerbungen von karbonpflanzen fijr museum der geologischen reichsansta1t (velebit).verh. geol. reichsans!. , 15,331-334, wien. kerner v. merilaun, f. (1916): alt und jungter­ twre pflanzenreste aus dem obcrsten cetinatalc. ­ verh. gcol. reisehsans!., 8,180-191, wien. kochansky-devide, v. (1981): prilozi povijes ti geoloskih znanosti ii hrvatskoj vi. paleobolanicka istrazivanja roberta visiania sibencanina.geo!. vjesnik, 33, 237-240. kochansky-devlde, v. & bajraktarevic, z. ( 1976): ficlls ef. carica l. u donjem sarmatu hrvatske.geol. vjesnik, 29, 409-410. kov ar-eder, j., habl y, l. & derek, t. ( 1995): neuhaus/klausenbach cine mioz~ine (pannone) pllanzenfundstelle aus dem sudlichen burgenland.­ jb. geol. b. -a ., 138/2,321-347, wien. mat, d.h. (1995): tertiarc vcgetationsgeschichte eu­ ropas. gustav fischer verlag, lena-stuttgart-new york, 640 p. mihajlov1c, d. (1990): paleogene flora of yugo­ slavia.proceedings of the symposium "paleoflori­ stic and paleoclimatic changes in the cretaceous and tertiary" (1989), 141 -146, prague. nemejc, f. (1936): contribution to the knowledge of the carboniferous flora of the coal measures at the northeastern foot of the velebit mountain (yollgo­ slavia).bull. intern. acad. boheme, 1-1 6, prague. obrhel,1. (1980): vznik a vyvoj paleobotaniky u ccchah (od najranljsich pocatku do roku 1870).­ acta univ. carolinae, geo!., 1-2, 107-134, praha. obrhel, j. (1984): vyvoj paleobotaniky y ceehah (v roku 1870 do roku 1918) .acta univ. carolinae, geol., 3, 261-283, praha. pantic, n. (1962): fosilni ostaei kopnenih biljaka u jugoslaviji i njihova stratigrafska vrijednosl.refe­ !"ati 5. savjetovanja geol fnrj, 107-1 15 , beograd. pantie, n. , kostic, v. & filipovic, i. (1976): karbonske tvorevine u jugos laviji i mogucnosti rekontrukcije razlicitih srcdina palcozojskog tetisa i njegovog oboda.geo!. anali balk. poluoslrva, 40, 45 -53, beograd. p1lar, gj. (j 883): flora fossilis susedana. descriptio plantarum fossilium quae in lapidicis ad ncdclja, sused, dolje etc. in vicitate civitatis zagrabiensis hujusquae reperta sunt.dj e ja lugos!. akad. znan. umjetn. , 4, viii+163 p. , zagreb. pollak, j. (1912): okamenjene sume. priroda , 2/1, 24-26, zagreb. polic, a. ( 1935): 0 oligoeenu i njegovoj nori kod planine u zagrebackoj gori. rad jug. akad . znan. umjetn., 251, 61 -90, zagreb. 170 radimsky, v. ( 1877): die insel pago in dalmatien und dercn lignilvorkommcn.bcrgund hlitten­ mann. lahrb., 25/3, 325-353, wien. schubert, r. (1909): geologija dalmacijc (preveo f. koch).matica dalmatinska, zadar, 181 p. sternberg, k.m. v. (18201838): versuch einer geognostisch-botanischen darslellung der flora del' vorwelt.fr. fleischer, 2. bde., fol io .i: i-i. i (1820), h. 2 (1829), h. 3 (1823), h. 4 (1825), h. 5 6 (1833) ii: 1838., 220+lxxi s, leipzig und prag. stur, d. (1868): fossile pflanzenreste aus dem sch i­ efergebirge von trgova in croatien.jahrb. geo!. reichsans!., 18/1, 131-138, wien. stur, d. (1872): pflanzenreste von vrdnik in syr­ mien .verh. gcol. rcichsans!., h. 17,340-431, wicn. sikic, l. & jovic, b. ( 1969): starost "gornjooligo­ ccnskih" naslaga sa smed im ugljenom u podrucju pregrade , sjcvc rna hrvatska.geo!. vjesnik, 22, 333-345. sinkovec, b. & sakac, k. (1982): thc paleogene bauxites of dalmatia.travaux com. intern. pour i'etude bauxites l 'aluminc ct d 'alum. , 12/17,293331, zagreb. spanic, d., rumeljak, lj. & jerinic, g. (1991): de te rmination of organic rich samples from the island of brae using organic geochemistry, organic petrology and palinology.2nd intern. symp. on the adriatic carbonate platform, zadar (1991), abs­ tracts, 113, zagreb. susniara, a. & sakac, k. (1988): miocenski i s latkovodni sedimenti podrucja sinja u srednjoj dalmaciji. geol. vjesnik, 41, 51-74. unger, f. (1838): reisennotizien von jahre 1838.­ steyermark. zeitschr. (n.f.), jahrb. 5, 75-128, graz. unger, f. (1840): dber die pilanzenund insecten­ rcstc von radoboj in croatien. leonhards u. bronns jahrb. min., 1840,374 p., frankfurt. geologia croarica 50/2 unger, f. (1850): fossile flora von radoboj.sitz­ ungsbcr. akad. wiss., 5, 405-406, wien. unger, f. (1868): die fossi le flora von radoboj.­ vcrh. gcol. reichsanst., h. 8, 176 p., wien. unger, f. (1869): die fossile flora von radoboj in ihrer gesamtheit lind nach ihren verhi:itnisse zur entwicklung del' vegetation der tertiarzeit. dcnk­ schr. akad. wiss. , math. na!. ci., 29, 125170, wien. vis1an1, r. (1858): piantc fossili della dalmazia. ­ mem. r. is!. veneto sci. lett. art., 7, 421-454, vene­ zia. vukotlnovic (farkas), lj. (1870): 0 petrefaktih (okaminah) u obce i 0 podzemnoj fauni j flori susedskih laporah.rad jugosl. akad. znan. umj­ ctn., 13, 172-212, zagreb. vukotinovic (farkas), lj. (1875a): 0 klasi ­ fikaciji u biljarstvu.rad jugosl. akad. znan. ulllj ­ etn., 31, 82-1 12, zagreb. vukotlnovic (farkas), lj. (1875b): 0 prom­ jcnljivosti biljnih i postanju novih vrs li.rad jugosl. akad. znan . umjetn., 33, 1-37, zagreb. vukotlnovic (farkas), lj. (1876): 0 dcsceden­ ciji iii rodoslovlju bilinah. rad jugosl. akad. znan. umjctn., 35,136-167, zagreb. vukotlnovic (farkas), lj. (1878): prinesci za geognosi u i botaniku hrvatske.rad jugosl. akad. wan. umjetn., 44, 175-220, zagrcb. ward, l.f. (1889): the geographical distribution of fossil plants. washington. zagar-sakac, a. & sakac. k. (1987): novi nalazi fosilnih lopoca (nymphacaccac) u tercijarnim naslagama dalmacije.rad jugosl. akad. znan. umjetn., 431, 207-218, zagreb. jungwinh: povijcsl pa1cobol;li1ickih islr.];i;ivanja u ilrvarskoj 171 a history of palaeobotanical studies in croatia in croa tia palaeobotanical studi es can be divided into seve ral phases si milarly to the czech "school of bolany" (obrhel, 1980, 1984) or in europe (ma l, 1995) . 1. "heroic period" (18381900) a long period with important and famous authors (heroes). unger wrote seve ral times about the palaeoflora of radoboj (unger, 1838, 1840, 1850,1868,1869), rollowing gbppen and his first nnalys is of pollen grains from malerial or radoboj (goppert, 1841). there are some works about the foss il flora of radoboj and mt. promina (y isiani, 1858; ettingshausen, 1850a, b, c, d, 1853, 1854, 1855, 1870, 1896; faldiga, 1898). geinitz (1868) rdered in short to rossil plants or the trgovska gora, as did stur (1868) who spoke abou t the foss il remains of sigillaria, and later wrote abo lit the fossil flora of vrd nik in s rijem. the first author or a palaeobotanical work in the croatian lan­ guage was yukotinoyic (1870). radim sky (1877) wrotc about the palaeooora or the island or pag. there followed a great work on a fossil plant co llection enli tled "descru ipt io plantarum fossi lium quae in lapidic is ad ncdclja , suscd, dolje etc. in civi nitate civi­ tatis zagrabiensis hujusquae repcrtae sunt " by pilar (1883). engelhardt (1884,1885,1890,1893) has described the fo ss il flora from podvin in siavon ia. kerner is well known for his work about the cretaceous ilora or the island or brai' (kerner, 1896 collection of conifers, e.g. cunninghamia e/egal/s corda , ferns and dicotyledons of a subtropic character). 2. "prestagnation period" ( 19021945) kerner has contribu ted with se rial works of foss il dora (ter­ tiary and early quaternary) from the dalmatia and sinj sko po lj e (kerner, 1902, 1905, 1906, 1907, 1916), triassic and carboniferous fo ss il remains or mi. svilaja (kerner, 1907) and velcbit (kerner, 1910). sc il ubert ( 1909) has mentioned sevcral times the fossil flora from the triassic of svilaja . the cretaceous of the is land of hvar, the eocene prom ina sedimen ts, and the neogene in the vici nity of sinj. croatian botanists adamoytc (1905), forenba­ cher (1910) and horvat (1928) wrote about the evolution of the t.ertiary flora of the balkan peninsul a, the tertiary flora in europe up to the present or about the hi story and spread of floristic c lements in no rth croatia and siavonia. ed ward s ( 1932) has given some inrormation about early eocene fossil plants of lst ria. latcr works include those or boros ( 1933), cernja ys kt (1933), cull rtlovic (1933), cer­ nja yski & kirilin (1934), nemejc (1936) and horvat (1939). 3. "period of stagnation" (1945 10 date) in th is long period severa l works have been writen by a few authors, e.g. cernjayskt ( 1949) describes a pi nc­ conc rrom sused, anic (1959) spcaks about the char­ acter of the flora and c limate of the tertiary in fnrj. pantic (1962) and pantic et al. (1976) mentioned the carboniferous foss il flora from mi. vclebit and the crctaceous nora or hvar. kochansky-devrde & llajraktarey1c ( 1976) described ficl1s cf. carica from lower sannatian sedi ments, while zagar­ sakac & sakac ( 1987) reported the finding or nymphaea arethuse from tertiary sed iments in the vic i­ nity or sinj. susnjara & sakac (1988) described freshwater sediments of miocene age with some rema­ ins of rossil plants. mii-iajlovtc ( 1990) prescnts the palaeogene fossil flora of yugoslavi a ( including the croatian localities of rasa and mi. promina). finally, severa l palynologica l analyses have been done (ora­ xler, 1986; jeri nic & jelen, 1991; spanic et ai., 1991; b ukov ac ct ai., 1995). finally, it is especially necessary to include herak's celebrated tex t-book "palaeobotany" (herak , 1953, 1963). manuscript received april 14, 1997. revised manuscript accepted november 10, 1997. 172 geologia croatica 50/2 ab stra ct several pleistocene hippopotamid remains have been collected from the italian peninsula, but some of them lack any stratigraphic data or details about the fossil localities. the hippopotamus was present in italy and western europe from the latest villafranchian (late early pleistocene), whereas the oldest records of the genus (coste san giacomo and chiusi basin) need to be confirmed by further evidence. hippopotamus antiquus is recorded from italy until mis 15, whereas h. amphibius is first known from the late middle pleistocene (mis 13 or 11) and survived in southern italy until mis 4/3. keywords: hippopotamus, chronology, pleistocene, italian peninsula  1. introduction the hippopotamus represents one of the african taxa that spread throughout europe during the early pleistocene (gliozzi et al., 1997; petronio et al., 2011; palombo, 2014). nevertheless the first occurrence of this genus in europe, in particular in the mediterranean area, is debated (petronio et al., 2011; palombo, 2014). the italian peninsula is quite rich in remains of pleistocene fossil hippopotami (caloi et al., 1980; petronio, 1986, 1995; mazza, 1995; gliozzi et al., 1997; petronio et al., 2011) and it surely plays an interesting role in documenting the dispersal pattern of this taxon.two species have been documented from the pleistocene in the italian peninsula: h. antiquus and h. amphibius. the first and last occurrences of these species, however, are still a matter of discussion among researchers (petronio, 1995; petronio et al., 2011; mancini et al., 2012; palombo, 2014). the aim of this comunication is to update and to clarify the chronological or biochronological limits of the hippopotamus in the italian peninsula. 2. materials and methods the hippopotamus remains considered in this work are housed at several italian museums and institutions. the italian specimens have been published or mentioned in several contributions, in particular leonardi (1948), maini (1952), maccagno (1962), blandamura & azzaroli (1977), caloi et al. (1980), petronio (1986, 1995), mazza (1995), mancini et al. (2012). the biochronological scheme mentioned in this note follows the work of gliozzi et al. (1997), petronio et al. (2011) and marra et al. (2014) (fig. 1). institutional abbreviations: museo di storia naturale, sezione di geologia e paleontologia, florence (igf); museo di anatomia comparata, sapienza, università di roma, rome (macur); museo civico di storia naturale a. doria, genova (mczg); museo di paleontologia, sapienza, università di roma, rome (mpur); museo di san giuliano, l’aquila, (msg); museo di storia naturale, accademia dei fisiocritici, siena (msnaf); museo di storia naturale della certosa di calci, pisa (msncc): geologia croatica 68/3 313–319 3 figs. zagreb 2015 a brief review of the occurrences of pleistocene hippopotamus (mammalia, hippopotamidae) in italy  luca pandolfi1 and carmelo petronio2 1 department of science, section of geology. university of roma tre. largo s. l. murialdo 1. 00146 roma, italy; (corresponding author: luca.pandolfi@uniroma3.it) 2 department of earth science. „sapienza” university of rome. piazzale aldo moro 5. 00185 roma, italy doi: 104154/gc.2015.24 geologia croaticageologia croatica geologia croatica 68/3geologia croatica 314 figure 1: correlation between geochronology, marine isotopic stages and the italian mammal units (after petronio et al., 2011 and marra et al., 2014). pandolfi & petronio: a brief review of the occurrences of pleistocene hippopotamus (mammalia, hippopotamidae) in italy geologia croatica 315 3. systematic palaeontology class mammalia linnaeus, 1758 order artiodactyla owen, 1848 family hippopotamidae gray, 1821 genus hippopotamus linnaeus, 1758 hippopotamus antiquus desmarest, 1822 (fig. 2, fig. 3a) chronological distribution: from the early pleistocene to the first half of the middle pleistocene. geographic distribution: europe and the levant. according to petronio (1995) the species also occured in northern africa during the pleistocene (ain hanech and ternifine, algeria): short remarks on distinctive cranial and mandibular features: the skull of h. antiquus is relatively long and slender. the zygomatic arches are transversally shorter than the transverse diameter between the external borders of the canine (desmarest, 1822; caloi et al., 1980). the sagittal crest is short (leonardi, 1947). the ventral border of the mandible is slightly concave in h. antiquus. the horizontal ramus of the mandible is relatively long and slender (caloi et al., 1980). hippopotamus amphibius linnaeus, 1758 (fig. 3b‒c) chronological distribution: from the early pleistocene (ca. 2 ma) to the present. geographic distribution: africa, europe (late middle and late pleistocene): short remarks on distinctive cranial and mandibular features: the skull of h. amphibius is relatively short and massive; the mastoid area is transversally well developed as well as the zygomatic arch (caloi et al., 1980). the sagitfigure 2: remains of hippopotamus antiquus from the chiusi basin. a) fragmentary mandible (msmaf nc) in lateral view; b) fragmentary mandible of a young individual (msnaf 4726): 1) in lateral view, 2) in occlusal view; c) lower canine (msnaf 4719) in lateral view; d) fragment of lower canine (msnaf 4718) in lateral view. scale bar equals 5 cm. geologia croatica 68/3geologia croatica 316 tal crest is longer than in h. antiquus (leonardi, 1947). the ventral border of the mandible in h. amphibius is convex but it appears straight in young individuals (caloi et al., 1980). the horizontal ramus of the mandible is high and short; the mandible appears massive with respect to that of h. antiquus. in addition, the two horizontal rami are slightly divergent in dorsal view. 4. occurrences of hippopotamus in the italian peninsula the first occurrence of the pleistocene hippopotamus in italy is controversial. until the end of the last century it was thought to have been in the early pleistocene sites of the upper valdarno, referred to approximately the end of the olduvai subchrone (tasso faunal unit according to gliozzi et al., 1997). however, according to napoleone et al. (2003), the upper valdarno specimens are probably younger and they ascribed them to the latest early pleistocene. during the latter time span, the hippopotamus was present at montecastrilli (terni), as well as at redicicoli and cava arnolfi (rome), madonna della strada (l’aquila), colle curti (macerata), il crostolo (reggio emilia) and in the mugello basin (tuscany) (ambrosetti & cremaschi, 1976; ficcarelli & mazza, 1990; abbazzi et al., 1995; coltorti et al., 1998; palombo et al., 2002; girotti et al., 2003; petronio et al., 2003; magri et al., 2010; petronio & pandolfi, 2011; petronio et al., 2011; kotsakis & pandolfi, 2012; mancini et al., 2012; marra et al., 2014; pandolfi et al., 2015): recently, bellucci et al. (2012) reported the presence of an incisor fragment of hippopotamus in the middle villafranchian assemblage of coste san giacomo (anagni basin). according to these authors, the specimen was found „in the field where most of the csg fu bones were previously collected“ (bellucci et al., 2012, p. 37). a large number of remains of hippopotamus housed at the msnaf have been collected from early pleistocene lacustrine deposits in the chiusi basin (tuscany) (cuscani politi, 1966, 1971; mazza, 1995) (fig. 2). among the other specimens, an almost complete mandible displays morphological features typical of h. antiquus: the horizontal rami are quite parallel and the lower border is slightly convex (cfr. caloi et al., 1980; fig. 2). the mammal assemblage from the chiusi basin, which is still being studied (pandolfi & petronio unpublished data), includes h. antiquus, gazella sp., axis cf. a. nestii and eucladoceros sp. on the whole, the assemblage from the chiusi basin suggests an age older than farneta fu (probably coste san giacomo or olivola fus) and supports the hypothesis of an early diffusion of hippopotamus in western europe. nevertheless, the specimens from the chiusi basin are surface finds (not-stratified) and the presence of two different faunal assemblages with different ages cannot be ruled out. in europe, chronologically early remains of hippopotamus, including a partial skull, have been collected from the early pleistocene deposit at elis (greece), approximately 2.0-1.8 ma (thenius, 1955; reimann & strauch, 2008; athanassiou & bouzas, 2010), while the genus was documented during the late early pleistocene in spain (venta micena, fuente nueva-3 and barranco león-5) (martínez-navarro et al., 2003; rook & martínez-navarro, 2010) and from the early-middle pleistocene transition in france (sainzelles, soleilhac and saint priest; palombo & valli, 2003; guérin et al., 2003). h. antiquus (or closely related forms also classified as h. tiberinus or h. ex gr. h. antiquus; see discussion in caloi et al., 1980; petronio, 1986, 1995; mazza, 1995; athanassiou & bouzas, 2010) was surely present in italy until mis 15. during this time, the species occurred at maglianella (rome) where a fragmentary skull and mandible belonging to the same individual have been collected (caloi et al., 1980; petronio, 1986, 1995; marra et al., 2014) and at via portuense (rome: marra et al., 2014). the fragmentary skull from maglianella (msncc) has elevated ocular orbits, the occipital face is inclined as in h. antiquus from s. oreste (rome) and the nuchal crest is marked. the mandible displays a slightly convex lower border of the horizontal ramus, which is relatively long and low (caloi et al., 1980; petronio, 1986, 1995). in the local fauna of fontana ranuccio (anagni basin, ca 0.41 ma, marra et al., 2014) the presence of h. cf. am­ phibius is reported by cassoli & segre naldini (1993). however the hippopotamus is represented only by a small fragment of lower incisor (cassoli & segre naldini, 1993, p. 36), as in the case of coste san giacomo, but it cannot be identified at specific level. an almost complete skull and mandible belonging to the same individual (mpur/v 149 and 149a) were reported by fabiani & maxia (1953) (fig. 3b) from the cava montanari, in the via flaminia (rome). the skull displays morphological characteristics close to the recent h. amphibius (e.g. the occipital condyles are not as far back as the occipital crest, the sagittal crest is relatively long and low: fig. 3b, c) as was extensively described by caloi et al. (1980). according to these authors, the original label of the above-mentioned specimens was reported as „cava nera molinario“ (via flaminia, rome) as the site of collection. therefore, they are likely to be a part of the mammal assemblage of the cava nera molinario, which includes cervus elaphus eostephanoceros and palaeoloxodon antiquus (marra et al., 2014), recovered within a sedimentary layer underlying the „tufo rosso a scorie nere” pyroclastic-flow deposit (452±2 ka, karner et al., 2001; di stefano & petronio, 1993; marra et al., 2014). this sedimentary layer is a fluvial-lacustrine deposit overlying the tufo del palatino pyroclastic-flow deposit (530±2 ka, karner et al., 2001; marra et al., 2009), and represents the aggradational succession of the valle giulia formation (marra & rosa, 1995), deposited during the sea-level rise of mis 13, between 530 and 500 ka (karner & marra, 1998). if the provenance from cava nera molinario is correct for the specimens mpur/v 149 and 149a, the earliest occurrence of h. am­ phibius in italy could be chronologically placed within mis 13. nevertheless, petronio (1995), palombo (2004) and kotsakis & barisone (2008) did not include the pandolfi & petronio: a brief review of the occurrences of pleistocene hippopotamus (mammalia, hippopotamidae) in italy geologia croatica 317 specimens mpur/v 149 and 149a in the list of remains collected at cava nera molinario and gave the general indication „tor di quinto“ as the locality of the skull and mandible. however, even if the provenance of the specimens could be tor di quinto or any other locality in rome along the via flaminia, the stratigraphic sections published by marra & rosa (1995) and pandolfi & marra (2015) reveal that the conglomerate levels outcropping in these areas can be chronologically placed within mis 13 or mis 11, ranging between 530 and 450 ka. the presence of h. amphibius in italy is also reported in several latest middle pleistocene localities (petronio et al., 2011), but the specimens collected at castel di guido (rome, mis 9) were referred to hippopotamus sp. and h. cf. antiquus by capasso barbato & petronio (1983) while mazza (1995) did not exclude an attribution to h. tiberinus (= h. antiquus according to petronio, 1995). moreover, the few specimens from malagrotta (rome, mis 9) appear indeterminable to specific level (caloi & palombo, 1980, 1988, 1994; mazza, 1995). hippopotamus cf. amphibius was recorded at sedia del diavolo (rome, ca 0.360 ma) by caloi et al. (1980) but mazza (1995) questioned this attribution as well as that of the fragmentary specimens from torre in pietra (rome, mis 9) ascribed to h. amphibius by caloi & palombo (1978). h. amphibius is reported during the latest middle pleistocene in france (palombo & valli, 2003 and references therein), whereas according to mazza (1995) one of the first records of h. amphibius is in the early late pleistocene site of barrington (england). in great britain, the species appears to have been present only during the last interglacial mis 5e (schreve, 2009) whereas it was recorded in southern italy as late as mis 4 (gliozzi et al., 1997; palombo, 2004; petronio et al., 2007, 2011). indeed, at grotta romanelli (lecce), hippopota­ mus has been documented from level g, which chronologically spans from ca. 69 to ca. 40 ka (blanc, 1920, 1928; fornaca rinaldi & radmilli, 1968; mazza, 1995; pandolfi & tagliacozzo, 2013) and overlies the level i with coelodonta antiquitatis (pandolfi & tagliaco z zo, 2013, 2015). h. amphibius has been recorded in the layer c2 of canale delle acque alte (latina) referred to the beginning of mis 4 (farina, 2011). the species has also been reported from sandy-clay sediments at ingarano (foggia: petronio & sardella, 1998). these sediments, which also contain c. antiquitatis (petronio & sardella, 1998), have been referred to mis 4 but their stratigraphic relationship with the cave sequence is unclear (petronio & sardella, 1998). hippopotamus has never been collected from avetrana bed 8 (taranto), recently referred to mis 4-3 (pandolfi et al., 2013; berté & pandolfi, 2014), probably due to the absence of a nearby relatively large water body. 5. conclusions several remains of pleistocene hippopotamuses have been collected from the italian peninsula but, unfortunately, some of them lack any stratigraphic data. hippopotamus was certainly present in the peninsula at the end of the villafranchian and afterwards. this is in agreement with the data on the occurrences of this taxon in europe and suggests a dispersal pattern of the genus from southeastern europe (greece: middle villafranchian) to western europe (spain: latest villafranchian) and throughout italy. the species h. antiquus occurred in the peninsula until mis 15. with the exception of the specimens mpur/v 149, which testify to the occurrence of h. amphibius in italy during the middle pleistocene, several other hippopotamus remains reported from localities chronologically related to mis 13-9 cannot be presently assigned to a well-defined species. however, these records suggest the continued presence of the genus in italy. the latest records of hippopotamus in the peninsula are from southern italy (apulia) where the taxon survived during mis 4 and the beginning of mis 3 (e.g., level g of grotta romanelli), confirming the role of this area as one of the last refugia of the genus in europe. acknowledgment we thank f. marra (ingv) for their contribution to the stratigraphy of the area of tor di quinto – via flaminia. we also thank all the curators of the cited museums and a. athanassiou and an anonymous reviewer for their useful suggestions. references abbazzi, l., benvenuti, m., rook, l. & masini, f. (1995): biochronology of the mugello intermontane basin (northern apennines, italy).– il quaternario, 8, 5–10. figure 3: skulls of hippopotamus in lateral view. a) hippopotamus antiquus from sant’oreste (mpur/v 1950); b) hippopotamus amphibius from tor di quinto (mpur/v 149); c) hippopotamus amphibius recent africa (macr nc). scale bar equals 10 cm. geologia croatica 68/3geologia croatica 318 ambrosetti, p. & cremaschi, m. (1976): segnalazione di una fauna villafranchiana superiore con libralces gallicus nei livelli fluviolacustri soprastanti alle faune calabriane ad artica islandica nei dintorni di reggio emilia.– boll. soc. geol. it., 94, 1361–1374. athanassiou, a. & bouzas, d. (2010): new hippopotamid finds in eurotas valley (laconia, greece).– sci. ann., sch. geol., aristotle university of thessaloniki proceedings of the xix cbga congress, thessaloniki, greece special volume, 99, 57–62. bellucci, l., mazzini, i., scardia, g., bruni, l., parenti, f., segre, a.g., naldini, e.s. & sardella, r. (2012): the site of coste san giacomo (early pleistocene, central italy): palaeoenvironmental analysis and biochronological overview.– quat. internat., 267, 30–39. bertè, d.f. & pandolfi, l. (2014): canis lupus (mammalia, canidae) from the late pleistocene deposit of avetrana (taranto, southern italy).– riv. it. paleont. str., 120/3, 367–379. blanc, g.a. (1920): grotta romanelli.– arch. antropol. etnol., 50/1–4, 1–39. blanc, g.a. (1928): grotta romanelli.– arch. antropol. etnol., 58/1–4, 1–49. blandamura, f. & azzarolli, a. (1977): l’„ippopotamo maggiore” di filippo nesti.– atti acc. naz. lincei, 14, 169–188. caloi, l. & palombo, m.r. (1978). anfibi, rettili e mammiferi di torre del pagliaccetto (torre in pietra, roma).– in: malatesta, a. (ed.): torre in pietra, roma. quaternaria, 20, 315–428. caloi, l. & palombo, m.r. (1980): resti di mammiferi del pleistocene medio di malagrotta (roma).‒ boll. serv. geol. it., 100, 141–188. caloi, l. & palombo, m.r. (1988): le mammalofaune plio-pleistoceniche dell’area laziale: problemi biostratigrafici ed implicazioni paleoclimatiche.– mem. soc. geol. it., 35, 99–126. caloi, l. & palombo, m.r. (1994): biocronologia e paleoecologia della mammalofaune del pleistocene medio dell’italia centrale.– studi geol. camerti volume speciale 1994 b, 503–514. caloi, l., palombo, m.r. & petronio, c. (1980): resti cranici di hippopotamus antiquus (= h. major) e hippopotamus amphibius conservati nel museo di paleontologia dell’università di roma.– geol. rom., 19, 91–119. capasso barbato, l. & petronio, c. (1983): la mammalofauna pleistocenica di castel di guido (roma).– boll. serv. geol. it., 102, 95–108. cassoli, p.f. & segre naldini, e. (1993): le faune di costa s. giacomo e fontana ranuccio.– in: gatti s. (ed.): dives anagnia, archeologia nella valle del sacco, l’erma, roma, 30–38. coltorti, m., albianelli, a., bertini, a., ficcarelli, g., laurenzi, m.a., napoleone, g. & torre, d. (1998): the colle curti mammal site in the colfiorito area (umbria-marchean apennine, italy): geomorphology, stratigraphy, paleomagnetism and palynology.– quat. internat., 47/48, 107–116. cuscani politi, p. (1966): resti di ippopotami provenienti dalla zona di chiusi.– atti acc. fisiocr. siena, sezione agraria, serie 2, 12, 1–44. cuscani politi, p. (1971): natura dei sedimenti in cui sono stati rinvenuti i resti di ippopotamo (della zona di chiusi) precedentemente studiati.– atti acc. fisiocr. siena, serie 14, 3, 1–13. desmarest, a.g. (1822): mammalogie, ou description des espèces des mammifères.– paris, veuve agasse, pp. i-viii, 277–555. di stefano, g. & petronio, c. (1993): a new cervus elaphus of middle pleistocene age.– n. jb. geol. paläont. abh., 190, 1–18. fabiani, r. & maxia, c. (1953): l’istituto e i musei di geologia e pale-l’istituto e i musei di geologia e paleontologia.– pubbl. istit. geol. paleontol. univ. st. roma, 9, 1–31. farina, s. (2011): late pleistocene-holocene mammals from „canale delle acque alte (canale mussolini)“ (agro pontino, latium).– boll. soc. paleontol. it., 50, 11–22. ficcarelli, g. & mazza, p. (1990): new fossil findings from the colfiorito basin (umbria-marchean apennine).– boll. soc. paleontol. it., 29, 245–247. fornaca-rinaldi, g. & radmilli, a.m. (1968): datazione con il metodo th230/u238 di stalagmiti contenute in depositi mousteriani.– atti soc. tosc. sci. nat., 75/2, 639–646. girotti, o., capasso barbato, l., esu, d., gliozzi, e., kotsakis, a., martinetto, e., petronio, c., sardella r. & squazzini, e. (2003): the section of torre picchio (terni, umbria, central italy): a villafranchian site rich in mammals, molluscs, ostracods and plants.– riv. it. paleont. str., 109, 77–98. gliozzi, e., abbazzi, l., ambrosetti, p.g., argenti, p., azzaroli, a., caloi, l., capasso barbato l., di stefano, g., ficcarelli, g., kotsakis, t., masini, f., mazza, p., mezzabotta, c., palombo, m.r., petronio, c., rook, l., sala, b., sardella, r., zanalda, e. & torre, d. (1997): biochronology of selected mammals, mollusch and ostracods from the middle pliocene to the late pleistocene in italy. the state of the art.– riv. it. paleont. str., 103, 369–388. guérin, c., dewolf, y. & lautridou, j.-p. (2003): révision d’un site paléontologique célèbre: saint-prest (chartres, france).– geobios, 36, 55–82. karner, d.b. & marra, f. (1998): correlation of fluviodeltaic aggradational sections with glacial climate history: a revision of the classical pleistocene stratigraphy of rome. geol. soc. am. bull. 110: 748–758. karner, d.b., marra, f. & renne, p.r. (2001): the history of the monti sabatini and alban hills volcanoes: groundwork for assessing volcanic-tectonic hazards for rome.– j. volcanol. geotherm. res., 107, 185–219. kotsakis, t. & barisone, g. (2008): i vertebrati fossili continentali del plio-pleistocene dell’area romana.– in: funiciello, r., praturlon, a. & giordano, g. (eds.): la geologia di roma, mem. descr. carta geol. it., 80, 115–143. kotsakis, t. & pandolfi, l. (2012): the plio-pleistocene mammal assemblages from the intra-apennine basins.– rend. online soc. geol. it., 23, 69–76. leonardi, p. (1948): l’ippopotamo del valdarno.– palaeontogr. ital., 43, 17–43. lisiecki, l.e. & raymo, m.e. (2005): a pliocene-pleistocene stack of 57 globally distributed benthic δ18o records. paleoceanography 20: pa 1003. doi:10.1029/2004pa001071. maccagno, a.m. (1962): l’elephas meridionalis nesti di contrada „ma-„ma-madonna della strada” scoppito (l’aquila).– atti accad. sci. fis. nat. na-atti accad. sci. fis. nat. na-. fis. nat. na-fis. nat. na-. nat. na-nat. na-. na-napoli, 4, 1–129. magri, d., di rita, f. & palombo, m.r. (2010): an early pleistocene interglacial record from an intermontane basin of central italy (scoppito, l’aquila).– quat. internat., 225, 106–113. maini, p.s. (1952): su alcuni resti di mammiferi quaternari rinvenuti a pagliara di sassa e cese di preturo (altipiano aquilano).– ann. ist. sup. sci. lett. s. chiara napoli, 4, 2–14. mancini, m., cavuoto, g., pandolfi, l., petronio, c., salari, l. & sardella, r. (2012): coupling basin infill history and mammal biochronology in a pleistocene intramontane basin: the case of western l’aquila basin (central apennines, italy).– quat. internat., 267, 62–77. marra, f. & rosa, c. (1995): stratigrafia e assetto geologico dell’area romana.– mem. descrit. carta geol. it., 50, 49–118. marra, f., karner, d.b., freda, c., gaeta, m. & renne, p.r. (2009). large mafi c eruptions at the alban hills volcanic district (cen-large mafic eruptions at the alban hills volcanic district (central italy): chronostratigraphy, petrography and eruptive behavior.– journ. of volc. and geoth. res., 179, 217–232. marra, f., pandolfi, l., petronio, c., di stefano, g., gaeta, m. & salari, l. (2014): reassessing the sedimentary deposits and vertebrate assemblages from ponte galeria area (rome, central italy): an archive for the middle pleistocene faunas of europe.– earth-sc. rev., 139, 104–122. martínez-navarro, b., espigares, m.p. & ros, s. (2003): estudio preliminar de las asociaciones de grandes mamiferos de fuente nueva-3 y barranco leon-5 (orce, granada, espaa).– in: toro, i., agustí, j. & martínez-navarro, b. (eds.): el pleistoceno inferior de barranco león y fuente nueva 3, orce (granada): memoria cientifica campañas 1999–2002. arqueologìa monografìas, consejerìa de cultura, junta de andalucìa, 115–136. mazza, p. (1995): new evidence on the pleistocene hippopotamuses of western europe.– geol. rom., 31, 61–241. napoleone, g., azzaroli, a. & mazzini, m. (2003): magnetochronologic significante of the end-pliocene age of the new found locality of poggio rosso in the upper valdarno, for dating its late villafranchian faunas.‒ riv. it. paleont. str., 107, 287–296. pandolfi & petronio: a brief review of the occurrences of pleistocene hippopotamus (mammalia, hippopotamidae) in italy geologia croatica 319 palombo, m.r. (2004): le mammalofaune della campagna romana: bio-le mammalofaune della campagna romana: biocronologia, paleoambienti.– ii congresso geosed, escursione precon-– ii congresso geosed, escursione preconii congresso geosed, escursione precon-ii congresso geosed, escursione precongresso, roma, 29 p. palombo, m.r. (2014): deconstructing mammal dispersals and faunal dynamics in sw europe during the quaternary.– quat. sci. rev., 96, 50–71. palombo, m.r. & valli, a.m.f. (2003): remarks on the biochronology of mammalian faunal complexes from the pliocene to the middle pleistocene in france.– geol. rom., 37, 145–163. palombo, m.r., azanza, b. & alberdi, m.t. (2002): italian mam-italian mammal biochronology from latest miocene to middle pleistocene: a multivariate approach.– geol. rom. 36, 335–368. pandolfi, l. & tagliacozzo, a. (2013): earliest occurrence of woolly rhino (coelodonta antiquitatis) in italy (late pleistocene, grotta romanelli site).– riv. it. paleont. str., 119/1, 125–129. pandolfi, l. & tagliacozzo, a. (2015): stephanorhinus hemitoechus (mammalia, rhinocerotidae) from the late pleistocene of valle radice (sora, central italy) and re-evaluation of the morphometric variability of the species in europe.– geobios, 48/2, 169–191. pandolfi, l. & marra, f. (2015): rhinocerotidae (mammalia, perissodactyla) from the chrono-stratigraphically constrained pleistocene deposits of the urban area of rome (central italy).– geobios, 48/2, 147–167. pandolfi, l., petronio, c. & salari, l. (2013): catastrophic death assemblages from the late pleistocene of italy: the case of avetrana karst filling (taranto, southern italy).– riv. it. paleont. str., 119/1, 104–124. pandolfi, l., grossi, f. & frezza, v. (2015): new insights into the pleistocene deposits of monte delle piche, rome, and remarks on the biochronology of continental hippopotamus (mammalia, hippopotamidae) and stephanorhinus etruscus (mammalia, rhinocerotidae) in italy.– estudios geol., 71/1, e026.http://dx.doi.org/10.3989/egeol.41796.337. petronio, c. (1986): nuovi resti di ippopotamo del pleistocene medioinferiore dei dintorni di roma e problemi di tassonomia e filogenesi del gruppo.– geol. rom., 25, 63–72. petronio, c. (1995): note on the taxonomy of pleistocene hippopotamuses.– ibex, 3, 53–55. petronio, c. & sardella, r. (1998): remarks on the stratigraphy and biochronology of the late pleistocene deposit of ingarano (apulia, southern italy).– riv. it. paleont. str., 104/2, 287–294. petronio, c. & pandolfi, l. (2011): first occurrence of the genus arvernoceros heintz 1970 from the late early pleistocene of italy.– riv. it. paleont. str., 117/3, 501–508. petronio, c., di canzio, e. & salari, l. (2007): the late pleistocene and holocene mammals in italy: new biochronological and paleoenvironmental data.– palaeontographica abt. a, 279, 147–157. petronio, c., argenti, p., caloi, l., esu, d., girotti, o. & sardella, r. (2003): updating villafranchian mollusc and mammal faunas of umbria and latium (central italy).– geol. rom., 36, 369–387. petronio, c., bellucci, l., martinetto, e., pandolfi, l. & salari, l. (2011): biochronology and palaeoenvironmental changes from the middle pliocene to the late pleistocene in central italy.– geodiversitas, 33, 485–517. reimann, c.k. & strauch, f. (2008): ein hippopotamus-schädel aus dem pliozän von elis (peloponnes, griechenland).– n. jb. geol. palä-n. jb. geol. paläont. abh., 249, 203–222. rook, l. & martínez-navarro, b. (2010): villafranchian: the long story of a plio-pleistocene european large mammal biochronologic unit.– quat. int., 219, 134–144. schreve, d.c. (2009): a new record of pleistocene hippopotamus from river severn terrace deposits, gloucester, uk – palaeoenvironmental setting and stratigraphical significance.– proc. geol. assoc., 120, 58–64. thenius, e. (1955): hippopotamus aus dem astien von elis (peloponnes).– ann. géol. pays hellén., 6, 206–212. manuscript received february 20, 2015 revised manuscript accepted september 07, 2015 available online october 31, 2015 1. introduction most pteridologists recognise selaginella beauv as the only genus of extant plants in the family selaginellaceae milde that contains about 700, mainly tropical, species (tryon & tryon, 1981). anisophyllous selaginella-like fossils are also known from the bolsovian onwards and thomas (2005) concluded that they were close enough to the anisophyllous species of extant selaginella to be included in that genus. however, the presence of three, not two, pairs of leaves necessitated the erection of a new sub-genus, hexaphyllum thomas, 2005. nevertherless, selaginella is a rare genus in the carboniferous with approximately ten named species and even some of these have not been described in sufficient detail. therefore, it was a great surprise when we found fragments of two tiny twigs of a selaginella after dissolving a small rock fragment with coalified leaves. this sample was taken from the borehole number h 42 in amasra during the iccp 575 meeting’s field excursion in turkey in 2010. 2. geological setting the sedimentation of the upper devonian and visean marine carbonates changed into terrestrial deposition during the upper visean and lower namurian in the bartin-amasra basin (derman and özçelik, 1993). the namurian alacaağzi formation, (up to 570 m thick in the amasra coalfield), is formed of sandstone, siltstone and claystone sequences with thin uneconomical coal seams in its upper part (canca, 1994; kerey et al., 1986). the westphalian kozlu formation (langsettian), is up to 900 m in thickness and composed of conglomerates, sandstones, mudstones and 18 mineable coal seams (canca, 1994; ab stra ct shoot fragments of a new species of selaginella beauv are described from the bolsovian (carboniferous period) of amasra, turkey. the shoots are heterophyllous with three paired ranks of different sized leaves enabling it to be referred to the subgenus hexaphyllum thomas. the size, shape and epidermal details of the leaves enable it to be differentiated from other pennsylvanian species and referred to a new species selaginella amasrae šimůnek & thomas, sp. nov. this new record extends the early distribution of the subgenus suggesting that it first appeared in eastern variscan euramerica and the intermontane basins of central europe, before spreading into the foreland basins of western euramerica. keywords: selaginella, carboniferous, turkey geologia croaticageologia croatica a new species of selaginella (selaginellaceae) from the bolsovian (carboniferous period) of the zonguldak – amasra coal basin, north-western turkey  zbyněk šimu° nek1 and barry a. thomas2 1 czech geological survey, klárov 3/131, 118 21 praha 1, czech republic; (zbynek.simunek@geology.cz) 2 institute of biological, environmental and rural sciences, aberystwyth university, aberystwyth, ceredigion sy231nl, uk; (bat@aber.ac.uk) doi: 104154/gc.2012.23 geologia croatica 65/3 345–350 1 tab. 2 pls. zagreb 2012 geologia croatica 65/3geologia croatica 346 kerey et al., 1986). the younger karadon formation (mostly duckmantian, bolsovian and asturian) comprises up to 550 m of conglomerates, sandstones and mudstones, and the lower part of this section contains the four most economical coal seams in the amasra coalfield (canca, 1994). the sediments in the lower parts of the karadon formation are grey to dark grey while in the upper parts they are reddish grey in colour. the subsequent permian aritdere formation contains red coloured conglomerates, sandstones and mudstones and is unfossiliferous. 3. material and methods a small fragment of black claystone with cordaites unger leaves was taken from the borehole core amasra, no. h 42, from a depth of 626.5 m (hema endüstri a.ş). this sample comes from the karadon formation and its age is bolsovian (moscovian) (canca, 1994). the cuticles were prepared by šimůnek using standard methods (kerp 1990; krings & kerp, 1997 and kerp & krings, 1999). the plant remains were released from the rock using concentable 1: comparison of the species s. gutbieri (göppert) thomas, s. stachygynandroiodes (geinitz) thomas, s. zeilleri (halle) thomas and s. amasrae šimůnek and thomas. s. g ut bi er i ( g ö pp er t) th o m a s s. st ac hy gy na nd ro io de s (g ei n it z) t h o m a s s. ze ill er i ( h a ll e) th o m a s s am as ra e ši m ů n ek an d th o m a s lateral leaves size <5 mm long 2 mm wide 6 mm long 2 mm broad 4.5–5.5 mm long 1.2 mm broad 1.2 mm long 600 μm broad angle of spread 50° 60–68° 60–68° 15° apex acute to acuminate elongate-acute to acuminate elongate-acute to acuminate elongate -acute margin apical third serrate entire entire dentate epidermal cells 42x10 μm 50–120x10–15 μm 70x15–20 μm c. 40x15 μm stomata 42x28 μm 60x20 μm 60x20 μm 35x20 μm median leaves size <1.6 mm long 0.2 mm broad 2.5mm long 1.2 mm broad 2.5 mm long 1.2 mm broad 950 μm long 300 μm broad angle of spread 10–15° 40° 40° 10–15° apex acute to acuminate acute acute acute margin entire apex slightly dentate distinctly dentate (teeth up to c. 400 μm long, 150 μm broad and c. 12 cells across at base) dentate in lower part with teeth up to c. 150 μm long and 50 μm broad and c. 6 cells across at base) epidermal cells 42x7 μm 20–115x10–15 μm 30-45x12 μm 25x15 μm stomata 35x18 μm 60x20 μm 60x20 μm 35x20 μm ventral leaves size 2 mm long 0.5 mm broad 1.5 mm long 0.25 mm broad 3 mm long 1 mm broad 550 μm long 200 μm broad angle of spread >10° >10° c. 5° parallel to axis apex acuminate acute margin dentate entire dentate entire epidermal cells 42x7 μm 20–60x15 μm 30–45x12 μm 25x10 μm stomata 35x18 μm 35x18 μm 60x20 μm not seen zbyněk šimůnek and barry a. thomas: a new species of selaginella (selaginellaceae) from the bolsovian (carboniferous period) of the zonguldak... geologia croatica 347 trated (38 %) hydrofluoric acid (hf) and then washed in distilled water. the resulting phytoleims were macerated in schulze solution (40 % nitric acid with a little potassium chlorate) for 27 hours and then bleached using 2 % potassium hydroxide solution until the whole oxidation products (brown) matter was released. after washing again in distilled water, some of the cuticles were mounted in glycerine jelly for light microscopy. some leaves were mounted on a metal stub for observation by sem. 4. description fragments of the following taxa were obtained by maceration: selaginella sp., cordaites sp., neuropteris sp., eusphe­ nopteris cf. sauveuri and eusphenopteris sp. observations here are restricted to selaginella. fragments of selaginella were mounted on two slides, 550/1–2 (coll. nos: zš 467 and 468), that are stored in the collections of the czech geological survey, prague. the sem stub with selaginella leaves is number 63, also in the czech geological survey collections. the largest fragment of selaginella is a small shoot about 7mm long and 2mm broad, while the other fragments show just a few leaves or portions of leaves. because they are such small pieces prepared by maceration, comparison with other species known as much larger shoots preserved as recognisable compressions is a little more difficult than usual. nevertheless, there are recognisable lateral, median and ventral leaves on the turkish specimens, the sizes of which, outlines and epidermal features were studied under the microscope. the lateral leaves depart at about 15 º from the axis and are about 1.2 mm long, 600 μm broad with elongate-acute apices and dentate margins. epidermal cells are elongated along the leaves, about 40 x 15 μm in size, and stomata are 30 x 20 μm. the median leaves depart at about 10–15° from the axis and are about 950 μm long, 300 μm broad with acute apices and dentate margins in their lower parts. epidermal cells are elongated along the leaves, about 25 x 15 μm in size, and stomata are 30 x 20 μm. the ventral leaves depart at about 10° from the axis and are about 550 μm long, 200 μm broad with acute apices and entire margins. epidermal cells are elongated along the leaves, about 25 x 10 μm large. no stomata could be seen. 5. comparison most plant fossils, like living plants, should be distinguishable on gross morphological features alone (thomas, 1997), but anatomical details of the epidermis have been shown to be valuable taxonomic features in fossil lycophytes. thomas (1966, 1967, 1968, 1970, 1974, 1976) showed this to be the case in arborescent lycophytes while thomas & masarati (1982), thomas (1985, 1992, 1997), thomas, b.a., cleal c.j. & barthel, m. (2004), bek et al. (2001) and thomas (2005) have shown the same to be true with herbaceous species. there are three species of carboniferous selaginella shoots that have been described in sufficient detail to be worthy of comparison with the turkish specimens. selaginella gutbieri (göppert) thomas, s. stachygynandroiodes (geinitz) thomas and s. zeilleri (halle) thomas are all known from leaf and epidermal characters. other species such as selaginellites elongatus (goldenberg) halle and paurodendron fraiponti (leclerq) fry need re-investigating, while others such as s. cf. leptostachys (goldenberg) thomas (bek et al., 2001) are not known in sufficient detail to make a detailed comparison with the turkish specimens. the characters of all four species are summarized in table 1 showing the differences in leaf size, leaf shape and epidermal characters. the most obvious difference between the new turkish selaginella and all the others is its much smaller overall size, with its correspondingly much smaller leaves. indeed, because of the small size, it might easily be overlooked if preserved as a compression on dark shale. the larger species, selaginella gutbieri, s. stachygynan­ droides and s. zeilleri are much more obvious as compressions with their spreading lateral leaves and overlapping median leaves. extant species of heterophyllous selaginella form full sized leaves close behind their growing apices, so it is extremely unlikely that the turkish shoots are parts of a larger plant. the size difference of the shoot and its leaves, together with the relatively tight arrangement of its leaves against the stem, the details of its leaf outlines and epidermal cells lead us to the conclusion that the turkish selaginella is a new species. 6. systematics class lycophyta family selaginellaceae selaginella p. beauv, subg. hexaphyllum thomas selaginella amasrae šimůnek & thomas, sp. nov. (pl. 1, figs. 1–6, pl. 2, figs. 1 and 2) anisomorphic shoot about 2mm broad with three paired ranks of leaves. lateral leaves spreading at 15° to the long axis, c.1.2 mm long, 600 μm broad near the base, apex elongate-acute, margins dentate, epidermal cells 40x15 μm, stomata 30x20 μm. median leaves spreading at 10–15° to the long axis c. 950 μm long. 300 μm broad near the base, apex acute, margins dentate in lower part, epidermal cells 20x15 μm, stomata 35x20 μm. ventral leaves parallel to the axis, 550 μm long and 200 μm broad near the base, apex acute, margins entire, epidermal cells 25x10 μm, stomata not seen. holotype: here designated (pl. 1, fig. 1), slide no: 550/1. repository: coll. no. zš 467 (slide 550/1) and zš 468 (slide 550/2) czech geological survey, klárov 3/131, 118 21 prague 1, czech republic. etymology: named after the coalfield where it was collected. geologia croatica 65/3geologia croatica 348 plate 1 selaginella amasrae šimu°nek & thomas sp. nov. specimen no: zš 467 (slide no: 550/1) except photo 2 = zš 468 (slide no: 550/2). 1 small shoot with its apex to the right, showing lateral leaves (a), median leaves (b) and ventral leaves (c), scale bar = 1 mm 2 folded basal part of a lateral leaf overlapping part of a lateral leaf scale bar = 200 μm. 3, 4 a median leaf, scale bar = 200 μm (3) and 100 μm (4). 5, 6 epidermis of lateral leaves showing epidermal cells and stomata, scale bar = 50 μm. (photo: z. šimůnek) zbyněk šimůnek and barry a. thomas: a new species of selaginella (selaginellaceae) from the bolsovian (carboniferous period) of the zonguldak... geologia croatica 349 plate 2 selaginella amasrae šimu°nek & thomas sp. nov. sem stub. no. 63. 1 basal fragment of lateral leaf with marginal teeth in sem, scale bar = 200 μm. 2 detail of marginal teeth in the leaf margin from fig. 1, scale bar = 20 μm. 7. discussion thomas (1992, 1997, 2005, 2009) summarised the stratigraphic ranges of the pennsylvanian selaginella fossils and suggested that the anisophyllous species made their first appearance in the bolsovian of the saar-lorraine basin (laveine, 1989) and the bolsovian of ovčín (pokrok), near radnice, western bohemia (bek et al., 2001). the new turkish species is comparable in age with these. more are known from the later asturian, having been described from the sydney mines formation, nova scotia, canada (bell, 1938), belgium (kidston, 1911), the bristol and somerset coalfield in england (thomas & cleal, 1994), zwickau in saxony, germany (thomas, 2005), sarr-lorraine, belgium and the nyřany group of coals, the nyřany member nyřany, plzeň basin (western bohemia); and ovčín (pokrok), near radnice, and the volcanic horizon directly overlying the lower radnice coal, radnice member (lower bolsovian), radnice basin western bohemia (bek et al., 2001). the new locality extends the early distribution of carboniferous anisophyllous species of selaginella to turkey. this new record appears to suggest that the subgenus hexa­ phyllum first appeared in eastern variscan euramerica and the intermontane basins of central europe before spreading into the foreland basins of western euramerica. the small size of the turkish selaginella suggests that many other similar specimens have been overlooked. it remains to be seen if new discoveries will add information that will give a clearer picture of the origins and distribution of the anisophyllous species of selaginella. acknowledgement this paper is a contribution to part of the international geoscience programme (igcp project 575) and was conducted with support of the grant agency of the czech republic (p210/10/0232) and the research aim of the czech geological survey (mzp0002579801). the authors thank to head of the hema company (amasra, turkey) for permission to study the borehole sample. references bek, j., opluštil, s. & drábková, j. (2001): two species of se­ laginella cones and their spores from the bohemian carboniferous continental basins of the czech republic.– rev. palaeobot. palynol., 114, 57–81. bell, w.a. (1938): fossil flora of sydney coalfield, northern nova scotia.– memoirs of the geological survey of canada, 215, 1–334. canca, n. (1994): geological maps in 1:100 000 scale of northwest bituminous basins of turkey, (in turkish).– mta publication. derman, a.s. & özçelik, y. (1993): stratigraphy and sedimentological properties of the palaeozoic units and possible palaeogeographic evolution of the western black see region, anatolia, turkey, (in turkish with english abstract).– ankara university, geology symposium for a. suat erk., september, 2–5 (1991), 11–20. kerey, i e., kelling, g. & wagner, r.h. (1986): an outline stratigraphy and paleobotanical records from the middle carboniferous rocks of northwestern turkey.– ann. soc. geol. nord., lille, 203–216. kerp, h. (1990): the study of fossil gymnosperms by means of cuticular analysis.– palaios, 5, 548–549. geologia croatica 65/3geologia croatica 350 kerp, h. & krings, m. (1999): light microscopy of fossil cuticles.– in: jones, t.p., rowe, n.p. (eds.): fossil plants and spores. modern techniques. geological society, london, 52–56. kidston, r. (1911): les végétaux houillers recueillis dans le hainaut belge.– polleunis & ceuterick, bruxelles, 22 pls., 282 p. krings, m. & kerp, h. (1997): an improved method for obtaining large pteridosperms cuticles.– rev. palaebot. palynol., 96, 453–456. laveine, j.-p. (1989): guide paléobotanique dans le terraine houiller sarro-lorraine.– houiller du bassin de lorraine, merlebach, 154 p. thomas, b.a. (1966): the cuticle of the lepidodendroid stem.– new phytologist, 65, 296–303. thomas, b.a. (1967): the cuticle of two species of bothrodendron (lycopsida: lepidodendrales).– journal of natural history, 1, 53– 60. thomas, b.a. (1968): a revision of the carboniferous lycopod genus eskdalia kidston.– palaeontology, 11, 439–444. thomas, b.a. (1970): epidermal studies in the interpretation of le­ pidodendron species.– palaeontology, 13, 145– 173. thomas, b.a. (1974): the lepidodendroid stoma.– palaeontology, 17, 525–539. thomas, b.a. (1976): epidermal studies in the interpretation of le­ pidophloios species.– palaeontology, 20, 273–293. thomas, b.a. (1985): selaginella the persistent pteridophyte.– pteridologist, 1. 2, 59. thomas, b.a. (1992): palaeozoic herbaceous lycophytes and the beginnings of the extant genera lycopodium and selaginella.– annals of the missouri botanical garden, 79, 623–631. thomas, b.a. (1997): upper carboniferous herbaceous lycopsids.– rev. of palaeobot. palynol., 95, 129–153. thomas, b.a. (1997): upper carboniferous herbaceous lycopsids.– rev. palaeobot. palynol., 95, 129–153. thomas, b.a. (2005): a reinvestigation of selaginella species from the asturian (westphalian d) of the wickau coalfiel, germany and their assignment to the new sub genus hexaphyllum.– z. dt. ges. geowiss., 156/3, 403–418. doi: 10.1127/1860-1804/205/0156-0403 thomas, b.a. & cleal, c.j. (1994): plant fossils from the writhlington geological nature reserve.– proceedings of the geologists’association, 105, 15–32. thomas, b.a., cleal, c.j. & bartel, m. (2004): palaeobotanical applications of incident light darkfield microscopy.– palaeontology, 47/6, 1641–1645. thomas, b.a. & masarati, d.l. (1982): cuticular and epidermal studies in fossil and living lycophytes.– in: cutler, d.f., alvin, k.l. & price, c.e. (eds.): the plant cuticle. linnean society symposium, london. series, 10, 363–378. tryon, r.m. & tryon, a.f. (1981): ferns and allied plants with special reference to tropical america.– springer, new york, 857 p. manuscript received february 13, 2012 revised manuscript accepted july 24, 2012 available online october 30, 2012 miraclevanja_dobarfile.indd 207 � ab stra ct revision of upper pleistocene lagomorph, canid, mustelid, and felid remains from veternica cave, croatia, eliminates previously-identifi ed “cold-adapted” taxa like mountain hare (lepus timidus), arctic fox (alopex lagopus), and wolverine (gulo gulo), and “steppe-adapted” animals like pika (ochotona sp.) from the faunal assemblage. our revision does not support an interpretation of signifi cant climatic oscillations during the deposition of layers associated with mis 2, 3, and 4. the removal of “cold-adapted” taxa suggests that either remains were deposited only during more temperate periods within mis 3 and 2 or that cold oscillations were not strongly expressed in northern croatia. the large mammal fauna is remarkably stable in composition over time. a wide range of environments – open, forested, wetland, and rocky – were usually present in the area surrounding veternica, and conditions in the region appear to have been broadly temperate. this apparent stability could be owing to one or more of the following factors: a) hominins and other animals preferentially used specifi c sites or the region during warm phases, b) sedimentation and erosion have created a bias for warm phases, c) climatic oscillations in the region were less marked than previously thought, d) local factors of microclimate and topography buffered faunal communities from climatic oscillations, and e) animals had wider temperature/precipitation tolerances than previously thought. keywords: pleistocene, mammal, croatia, neandertal, palaeoecology, veternica cave the palaeoecological signifi cance of the pleistocene mammalian fauna from veternica cave, croatia. revision of the lagomorpha, canidae, mustelidae and felidae � preston t. miracle1 and dejana brajković2 1 department of archaeology, university of cambridge, cambridge cb2 3dz, uk; (ptm21@cam.ac.uk; tel: +44(0)1223-333-532, fax: +44(0)1223-333-503) 2 institute for quaternary geology and paleontology, croatian academy of sciences and arts, a. kovačića 5, 10000 zagreb, croatia; (zpgkvartar@hazu.hr) doi: 104154/gc.2010.18 geologia croatica 63/2 207–224 16 figs. 9 tabs. zagreb 2010 geologia croaticageologia croatica 1. introduction the balkan peninsula has served as a stage for meetings, contacts, movements, and exchanges since well back in the neogene to the present day, regardless of whether the elements under consideration are tectonic plates, weather systems, vegetation communities, animal species, human cultures, or religions. our interest here is in the intersection between changing climates and mammalian communities. in studies of faunal changes during the pleistocene, these themes have been variously pursued in terms of when and from whence new populations and species have evolved and migrated into or within europe (kurtén, 1968; guérin & patou-mathis, 1996). geologia croatica 63/2geologia croatica 208 1. how common were cold-adapted taxa in the region during the upper pleistocene (mis 5–2), and how do these mammalian records compare to other proxies of climatic change? 2. did the balkans serve as a refugium for mammals during cold events during the upper pleistocene? 2. veternica cave veternica is a signifi cant and well-known speleological, palaeontological, and archaeological site in the croatian zagorje. the croatian zagorje is crucial to studies of the pleistocene of the region owing to the long stratigraphic sequ ences and important fossil remains contained in its numerous cave sites. among these sites are krapina (gorjanović-kramberg er, 1906; frayer, 2006), vindija (vuković, 1954; malez et al., 1980), velika pećina (malez, 1986), and veternica (malez, 1963). the fi rst two sites are particularly signifi cant because of their large collections of neanderthal fossils. veternica is located about 9 km west of the centre of zagreb, croatia, on the southwestern slope of medvednica. the southeastern-facing entrance is about 8 m wide and 4 m high, and beyond it is an entrance chamber (15 x 7 m), “left hall” (14 x 3–7 m) followed by several kilometres of passageways and canals (malez, 1963, 1965; božičević, 1995). quaternary sediments were excavated over an area of approximately 207 m2 by malez from 1951–1955 and in 1970 in trenches in front of the cave, in the entrance chamber, and in the left hall (miracle & brajković, 1992). in the most complete profi les (excavated to a depth of ca. 8 m) 11 geological layers were identifi ed. layer k was sterile. layer j probably dates to the last interglacial (mis 5) on the basis of the associated faunal assemblage (malez, 1963; miracle & brajković, 1992). layers h, i, j contained evidence of hominin occupation from frequent mousterian lithic artefacts and hearth features; charcoal from a hearth in layer i was radiocarbon dated at >43,200 bp (grn-4984) (malez, 1979a, 218). layer g consisted mostly of large rock rubble and was found primarily in front of the cave and in the entrance chamber; it was sterile of archaeological or palaeontological remains except for a few cave bear bones near the contact with level h (malez, 1965, 207). layers d, e, and f contained few archaeological and palaeontological fi nds other than the abundant remains of cave bears. several non-diagnostic stone tools were found in layer f (malez, 1979b, 269), and layer d contained a few lithic artefacts and a hearth (malez, 1965, 203). overlying these sediments was layer c, a dripstone radiocarbon dated to the mid-holocene to late pleistocene (malez, 1979a, 218). the uppermost layers, a and b, were rich in organic material, faunal remains, and artefacts from the neolithic to medieval periods. 3. methods our methods are similar to those used in an earlier revision of the pleistocene ungulate remains from veternica (miracle & brajković, 1992). identifi cations were made in the balkans have been recognized as a key region for examining faunal changes during the pleistocene owing to the fact that they were an important glacial refugium for plant and animal species (bennett et al., 1991; taberlet et al., 1998; hewitt, 2000; sommer & nadachowski, 2006). they sit on one of the major routes in and out of europe, and straddle a region of signifi cant changes between climatic-vegetation regions to the north and south. it is well established that during periods of climatic amelioration, taxa expanded from the balkans to the north. likewise, during glacial periods there was an expansion of more open environments supporting steppic vegetation, although some woodland remained in the region (willis & van andel, 2004). with the expansion of more open environments came mammals adapted to more open environments; there is a repeated pattern of incursions of “asiatic” taxa into europe during glacial periods (kahlke, 1999; kurtén, 1968; sala et al., 1992). during periods of glacial advance coldadapted taxa such as mammoth (mammuthus primigenius) and reindeer (rangifer tarandus) are commonly found in refugia of southern europe where they co-exist with temperate elements like roe deer (capreolus capreolus), red deer (cervus elaphus), aurochs (bos primigenius), boar (sus scrofa), and red fox (vulpes vulpes) (sommer & nadachowski, 2006, p. 258). recent work on pleistocene faunas in iberia has shown that cold-adapted taxa fi rst appeared on the peninsula during mis 6, and that they became more common during distinct pulses in mis 3 and mis 2 (álvarez-lao & garciá, 2010). these results are in broad agreement with other palaeoclimatic proxies in the region (idem). the situation in the balkans, however, is less clear. malez (1972) registered the presence of many “cold-adapted” taxa in the region of former yugoslavia and gave particular emphasis to shifts in faunal composition at the cave sites of veternica (malez, 1963), velika pećina (malez, 1986), and vindija (malez & rukavina, 1979). the faunal lists from these sites were used to correlate different assemblages, determine their relative ages, and reconstruct ice age climates. from these results malez (1979a) reconstructed a series of oscillations between colder and warmer conditions during the upper pleistocene in the region. we lack, however, adequate absolute dates to confi rm these associations and sequences of change. furthermore, revision of ungulate assemblages from veternica (miracle & brajković, 1992) and velika pećina (brajković & miracle, 1995) suggests that the originally published determinations should be treated with caution. the primary purpose of this paper is to help clarify the picture of upper pleistocene faunal change in the balkans by revising the lagomorph and smaller carnivore assemblages from veternica cave. we have focused in particular on “cold-adapted” taxa. the present contribution is thus part of a larger project of revision and re-dating of the existing faunal assemblages from the croatian zagorje (miracle et al., 2010). this revision of the veternica mammalian assemblages is used to address several questions as a step toward a better understanding of the pattern and nature of late pleistocene faunal changes in the balkans. miracle and brajković: the palaeoecological signifi cance of the pleistocene mammalian fauna from veternica cave, croatia... geologia croatica 209 and morphology of the i1; the remainder of the hare remains from layers d and e were also identifi ed to l. timidus on the basis of the determination of the incisors. the conclusive identifi cation of lagomorph remains depends on the morphology and dimensions of the upper and lower incisors, the morphology of the p2, and the relative length of the frontal to the nasal bones (koby, 1959, corbet, 1966, 182–183). of these characters, the morphology and dimensions of the incisors are particularly useful; these teeth are commonly preserved and the contrasts in dimensions are easily shown with simple, bivariate plots. l. timidus has incisors with a quadratic cross section while in l. europaeus incisors have a more rectangular cross section (koby, 1959, 1960; poplin, 1976; stampfli, 1983). this contrast can be clearly presented in a bivariate plot of incisor length (mesial-distal) against breadth (buccal-lingual)5. in fig. 1 we compare these dimensions for the upper incisors from veternica to the established range of variation the fi rst instance using the extensive recent comparative collections curated at the institute for quaternary palaeontology and geology of the croatian academy of sciences and arts, zagreb (zpgk). comparative measurements on recent specimens were made by miracle on collections housed in the cambridge university museum of zoology (cumz), the cambridge university clark laboratory for zooarchaeology (cuclz), and the university of michigan museum of zoology (ummz). considerable use was also made of large palaeontological and zooarchaeological collections from sites such as šandalja ii (miracle, 1995, 1996, 2007a), as well as relevant literature (e.g. carnivores: bonifay, 1971; poplin, 1976; argant, 1996; döppes, 2001; altuna, 2004; lagomorphs: koby, 1959, 1960; chaline, 1966; poplin, 1976; donard, 1981; stampfli, 1983; suárez & mein, 2004). unless otherwise indicated, all measurements are after driesch (1976) and were made using digital calipers (rounded to 0.1 mm). the pleistocene assemblages from veternica are dominated by the remains of cave bear (ca. 75% of nisp), and we have not studied these remains. likewise, we have not considered the holocene assemblages from layers b and a beyond measuring the remains of hare (lepus europaeus) for comparative purposes. 4. palaeontological revision of the veternica assemblages 4.1. lagomorpha 4.1.1. leporidae lepus timidus material1: layer d: a fragmentary skull with p3–m2 left and p3–m2 right (vtr. 220)2; a right i1 (vtr. 221); a left i1 (vtr. 222); a left mandible with i1, p3–m2 (vtr. 218); a right i1 (vtr. 223); a right m2 (vtr. 224); a right m3 (vtr. 225)3; a left m1 (vtr. 226); a left m2 (vtr. 227); a left m3 (vtr. 228); an atlas (vtr. 217); 2 right humeri (vtr. 203, vtr. 204); a right radius (vtr. 205); a right metacarpal iii (vtr. 213); a right tibia (vtr. 229); 2 left tibiae (vtr. 230, 231); a right metatarsal ii (vtr. 215); a right metatarsal iii (vtr. 214); layer e: a left innominate (vtr. 212); a left radius (vtr. 206); layer f: a right mandible with i1, p3–m3 (vtr. 219)4. the majority of the lagomorph remains from veternica were identifi ed by malez (1963, 20–24) to mountain hare, lepus timidus. the basis of this determination was the shape fi gu re 1: length (l, mesial-distal, at occlusal surface) against breadth (b, buccal-lingual, at occlusal surface) of i1 from veternica compared to recent remains of lepus europaeus (zpgk) and lepus timidus (cuclz) and fossil remains of l. europaeus (holocene layer b at veternica; betalov spodmol, rakovec, 1959; šandalja ii, miracle, 1995) and l. timidus (betalov spodmol, rakovec, 1959; šandalja ii, miracle, 1995). the boxes show the range of variation proposed by koby (1959, 37). measurements on recent material from croatia extend the range of variation of l. europaeus. 1 a right m3, right p3, and left metatarsal i reported by malez (1963, 20) were not found. 2 right and left p2 and left m3 reported by malez (1963, 20) were not found. 3 vtr. 224 and vtr. 225 were found among the lagomorph remains identifi ed to lepus timidus from layer d, but were not included in the monograph (malez, 1963). 4 vtr. 219 is reported to have come from layer e (malez, 1963, 21). the associated stratigraphic label was “layer f”, and this specimen may account for the indicated presence of lepus timidus in layer f on the summary table of faunal changes (malez, 1963, table 33). 5 these dimensions are measured as cross-sections near the occlusal surface. geologia croatica 63/2geologia croatica 210 of different hare species as established by koby (1959), as well as to pleistocene and recent comparative specimens. the dimensions of the veternica i1 are well within the range of l. europaeus (fig. 1). measurements on recent comparative material of l. europaeus from croatia show that the range of variation is considerably wider than that proposed by koby (1959). nonetheless, upper incisors from l. timidus continue to have broader occlusal surfaces for their lengths (fig. 1). turning to morphology, both incisors are closer to l. europaeus than to l. timidus. in both cases the furrow on the buccal surface of the incisor is not fi lled with dental cement; such an infi lling is commonly present in l. timidus and is not found in l. europaeus (chaline, 1966, 406; donard, 1981). furthermore the furrow on the buccal surface forms a wide “v” in cross-section, which is more similar to l. europaeus than l. timidus (chaline, 1966, 406; donard, 1981). thus, based on both the cross-sectional dimensions of the incisors as well as their morphology, we have revised the identifi cation of these specimens from l. timidus to l. europaeus. lower incisors of l. timidus and l. europaeus vary in their dimensions in a manner similar to that of the upper incisors. the cross-sectional dimensions of lower incisors identifi ed to l. timidus by malez (1963) are plotted in fig. 2. vtr. 219 and 223 both lie within the range of variation for l. europaeus proposed by koby (1959). the revision of these teeth from l. timidus to l. europaeaus is straightforward. although vtr. 218 is slightly smaller than the range of variation for l. europaeus proposed by koby (1959), its relatively great occlusal length relative to breadth aligns it with the distribution of measurements of l. europaeus. we thus have revised all of the lower incisors identifi ed to l. timidus to l. europaeaus. therefore, the most characteristic lagomorph elements have been shown to come from l. europaeus rather than l. timidus. koby (1959, 41) observed that alpine variable hares tend to be smaller in body size than brown hares, but cautioned that the dimensions of individual bones are not diagnostic to species. the situation is further complicated by the large size attained by arctic variable hares, apparently in accordance with bergmann’s rule, which is comparable to that of brown hares. on the other hand, the pleistocene remains of variable hares that koby (1960, 168–170) studied had smaller limb bone lengths than those of recent brown hares. comparison of long bone lengths of recent and fossil samples of l. europaeus and l. timidus confi rms koby’s observations (table 1). despite the overlapping ranges of variation, it is still possible in some cases to identify individual long bones to species. a right humerus (vtr. 204) from layer d has a greatest length (gl) of 110.1 mm; it is not only larger than two humeri from layer b (table 2) identifi ed by malez (1963, 9), but it lies beyond the range of l. timidus (table 1). we have revised it from l. timidus to l. europaeus. a right radius (vtr. 206) from layer e with gl = 117.5 is beyond the range of l. timidus, while a left radius (vtr. 205) from layer d with gl = 114.5 is at the very top end of the range of l. timidus (table 1). we have revised both specimens from l. timidus to l. europaeus. only two bones, tibiae vtr. 229 and vtr. 230 from layer d, have gl (140.3 mm and 140.4 mm, respectively) smaller than the range of variation for l. europaeus (table 1). these tibiae are likely from the same individual (malez, 1963, 23). given the positive identifi cation of l. europaeus from the same layer, we think that they were more likely from an unusually shortlegged l. europaeus rather than from l. timidus. given the uncertainties around these specimens, we assign them to lepus sp. we have not revised the identifi cation of undiagnostic hare remains assigned by malez to lepus sp., although we note that the dimensions of these specimens are similar to those of recent l. europaeus. we thus have revised specimens identifi ed to l. timidus by malez (1963, 20–24) to either l. europaeus or to lepus sp. (table 3). lepus sp. material: layer h: right distal humerus (vtr. 208); right distal radius (vtr. 207); right distal femur (vtr. 210); layer i: left innominate (vtr. 211); right distal tibia (vtr. 209). fi gu re 2: length (l, mesial-distal, at occlusal surface) against breadth (b, buccal-lingual, at occlusal surface) of lower fi rst incisors from veternica compared to remains of l. europaeus and l. timidus from recent comparative material (l. europaeus), holocene layer b at veternica (l. europaeus) and late glacial layers at šandalja ii (l. europaeus and l. timidus, miracle, 1995). the boxes show the range of variation proposed by koby (1959, 37). table 1: long bone dimensions (gl = greatest length) of recent lepus europaeus (zpgk; poplin, 1976) and lepus timidus (cuclz; poplin, 1976), and fossil l. europaeaus (table 2) and l. timidus (abri pataud, bouchud, 1975). lepus timidus lepus europaeus element, measurement mean range (mm) n mean range (mm) n humerus, gl 98.4 93.5–104.5 8 107.5 102–113 12 radius, gl 103.2 98.1–108.4 7 115.1 112.7–117.9 6 femur, gl 126.5 121–134 4 134.9 127–140 9 tibia, gl 143.6 136.5–154.3 6 153.6 143–158.8 9 miracle and brajković: the palaeoecological signifi cance of the pleistocene mammalian fauna from veternica cave, croatia... geologia croatica 211 hare remains recovered from layers h and i at veternica were considered not to be suffi ciently characteristic for specifi c determination; hence malez (1963, 24) identifi ed them only to genus. we agree with these determinations, and have not changed any of them. measurements for these specimens are presented in table 2 for comparative purposes. 4.1.2. ochotonidae ochotona sp. material: layer f6: right i1 (vtr. 269) malez (1963, 24–25) assigned a single right i1 to ochotona sp. (pika) on the basis of its anatomical-morphological characteristics and proportions, although he noted that its dimensions were somewhat greater than a specimen identifi ed to o. pusilla from ukraine. a lateral view and cross-section of the incisor were published several years later (malez, 1966, 6; malez, 1968, 148). the morphology of this tooth differs considerably from ochotona in lateral view (fig. 3). in ochotona the occlusal surface extends much further down the lingual side of the tooth than is the case in lepus; vtr. 269 is similar to lepus and differs from ochotona. comparison of a cross section of the crown to recent and fossil specimens of ochotona, orcytolagus (rabbit), and lepus (hare) shows that the morphology of the tooth is similar to lepus and very different from ochotona (fig. 4). furthermore, in leporidae the mesial face of the i1 of juvenile specimens is slightly rounded and becomes more rounded in table 2: measurements on remains identifi ed to l. europaeus and lepus sp. from veternica. measurements on incisors are as defi ned in fig. 1; other measurements are as defi ned in driesch (1976). # layer element species gl gb bfcr bfcd glf lad # layer element species l b vtr. 217 d atlas lepus sp. 15.7 33.7 18.2 14.9 13.5 7.8 vtr. 221 d i1 l. europaeus 3.3 2.1 # layer element species gl dp bd vtr. 222 d i1 l. europaeus 3.3 2.2 vtr. 203 d humerus lepus sp. 104.5 20.6 12.6 vtr. 218 d i1 l. europaeus 2.8 2.3 vtr. 204 d humerus l. europaeus 110.1 17.3 12.5 vtr. 219 f i1 l. europaeus 3.2 2.4 vtr. 208 h humerus lepus sp. 12.6 vtr. 223 d i1 l. europaeus 3.3 2.3 vtr. 235 b humerus l. europaeus 104.6 12.7 vtr. 232 b i1 l. europaeus 3.1 2.4 vtr. 236 b humerus l. europaeus 106.4 12 vtr. 233 b i1 l. europaeus 3 2.4 vtr. 237 b humerus l. europaeus 12.8 vtr. 234 b i1 l. europaeus 3.2 2.3 # layer element species gl bp bd # layer element species l p3-m3 vtr. 205 d radius l. europaeus 114.5 9.5 10.7 vtr. 220 d maxilla lepus sp. 18 vtr. 206 e radius l. europaeus 117.5 9.9 vtr. 220 d maxilla lepus sp. 18.3 vtr. 207 h radius lepus sp. 11.6 vtr. 218 d mandible l. europaeus 19 vtr. 238 b radius l. europaeus 117.9 9.1 9.6 vtr. 219 f mandible l. europaeus 21.2 # layer element species gl bp dc bd vtr. 232 b mandible l. europaeus 19.2 vtr. 210 h femur lepus sp. 20.6 vtr. 233 b mandible l. europaeus 17.7 vtr. 241 b femur l. europaeus 135.3 29.9 9.8 20.5 vtr. 234 b mandible l. europaeus 18.9 vtr. 242 b femur l. europaeus 136.1 28.7 10.2 20 # layer element species la vtr. 243 b femur l. europaeus 10.7 20.8 vtr. 211 i innominate lepus sp. 12.1 vtr. 244 b femur l. europaeus 28.9 10 20.4 vtr. 212 e innominate lepus sp. 12.7 # layer element species gl bp bd dd vtr. 246 b innominate l. europaeus 12.1 vtr. 209 i tibia lepus sp. 20.8 # layer element species gl vtr. 229 d tibia lepus sp. 140.3 21.2 16.9 10.3 vtr. 213 d metacarpal iii lepus sp 33.4 vtr. 230 d tibia lepus sp. 140.4 21.4 17 10.4 vtr. 252 b metacarpal iii l. europaeus 39.7 vtr. 231 d tibia lepus sp. 16.1 10.5 vtr. 247 b metatarsal ii l. europaeus 59.7 vtr. 239 b tibia l. europaeus 154.8 20.6 15.6 10.2 vtr. 248 b metatarsal ii l. europaeus 53.6 vtr. 240 b tibia l. europaeus 153.9 21.6 16.4 10.5 vtr. 249 b metatarsal ii l. europaeus 58.3 vtr. 245 b tibia l. europaeus 158.8 21.4 16.7 10.6 vtr. 250 b metatarsal iii l. europaeus 61.2 vtr. 214 d metatarsal iv lepus sp. 52.2 vtr. 251 b metatarsal iv l. europaeus 53.6 6 the material is labelled “layer f”, while in the literature it is assigned to “layer e” (malez, 1963, 24). we consider the original label to be more reliable than the publication, and hence assign the incisor to layer f. geologia croatica 63/2geologia croatica 212 adults, while in ochotonidae the mesial face is straight in juveniles and adults. another indication that this tooth is from a juvenile is the thinness of the enamel and the restriction of dentine in the tooth to the region near the occlusal surface. finally, enamel is present on the mesial side of i1 in leporidae, while it is missing in ochotonidae (suárez & mein, 2004, s120). a bivariate plot of mesial-distal length (l) against buccal-lingual breadth (b) shows that this tooth is indeed larger than ochotona, while smaller than adult specimens from orcytolagus and lepus (fig. 5). lagomorph incisors, however, grow continuously and deciduous teeth are not replaced by permanent incisors; incisors are small in juveniles and increase in both mesial-distal length and buccal-lingual breadth until maturation (suárez & mein, 2004, s120). vtr. 269 is larger than juvenile specimens of orcytolagus; furthermore the cross-sectional dimensions increase from l = 2.00 mm, b = 1.33 mm at the occlusal surface7 to l = 2.64 mm, b = 1.76 mm just above the break on the tooth, which is already at the lower end of the range of variation for adult lepus (fig. 5). hence, this i1 would have grown much larger in an adult, and based on size and morphology, we have revised it from ochotona sp. to lepus sp. table 3: revision of lagomorpha from veternica. # element layer malez (1963) revised vtr. 269 i1 f ochotona sp. lepus sp. vtr. 221 i1 d l. timidus l. europaeus vtr. 222 i1 d l. timidus l. europaeus vtr. 218 mandible with i1, p3 – m2 d l. timidus l. europaeus vtr. 223 i1 d l. timidus l. europaeus vtr. 204 humerus d l. timidus l. europaeus vtr. 205 radius d l. timidus l. europaeus vtr. 206 radius e l. timidus l. europaeus vtr. 219 mandible with i1, p3-m3 f l. timidus l. europaeus vtr. 220 fragmentary skull d l. timidus lepus sp. vtr. 226 m1 d l. timidus lepus sp. vtr. 227 m2 d l. timidus lepus sp. vtr. 228 m3 d l. timidus lepus sp. vtr. 217 atlas d l. timidus lepus sp. vtr. 203 humerus d l. timidus lepus sp. vtr. 213 metacarpal iii d l. timidus lepus sp. vtr. 229 tibia d l. timidus lepus sp. vtr. 230 tibia d l. timidus lepus sp. vtr. 231 tibia d l. timidus lepus sp. vtr. 215 metatarsal ii d l. timidus lepus sp. vtr. 214 metatarsal iii d l. timidus mt iv, lepus sp. vtr. 212 innominate e l. timidus lepus sp. fi gu re 3: revision of i1 (vtr. 269), lateral view: a) ochotona pusilla (cumz), b) vtr. 269, c) l. europaeus (zpgk). fi gu re 5: i1 mesial-distal length vs. buccal-lingual breadth in lagomorpha compared to vtr. 269. comparative measurements from comparative material and sources as follows: ochotona (cumz; malez, 1963, p. 25; suarez & mein, 2004, fi g. 5); l. europaeus (cumz; zpgk); l. timidus (cumz; rakovec, 1959; miracle, 1995); orcytolagus (cuclz; suarez & mein, 2004, fi g. 5). fi gu re 4: revision of i1 (vtr. 269), occlusal view: a) ochotona sp. (after hillson, 2005, fi g. 1.77), b) vtr. 269 (after malez, 1966, fi g. 1a), c) l. europaeus (after donard, 1981, fi g. 1). 7 malez (1963, 25) reported these dimensions as mesial-distal l = 1.9 mm, lingual-buccal b = 1.35 mm. a. b. c. 1 mm a. 1 mm b. c. miracle and brajković: the palaeoecological signifi cance of the pleistocene mammalian fauna from veternica cave, croatia... geologia croatica 213 4.2. carnivora 4.2.1. canidae alopex (cf.) lagopus material: layer f: left ulna (vtr. 255) a left ulna (vtr. 255, layer f) was attributed by malez (1963, p. 64–66) to arctic fox, alopex cf. lagopus. this specimen is well preserved and complete except for the distal end, which is missing (fig. 6). malez (1963, 64) noted that the general morphology of the ulna was like that of recent representatives of vulpes vulpes, but that vtr. 255 was much smaller and differed in specifi c morphological details from v. vulpes ulnae. the primary criteria that malez (1963, 65) used to identify the ulna to a. lagopus were 1) the morphology of the volar face of the proximal end and 2) the cross-sectional morphology of the diaphysis. malez (1963, 64) suggested that the key morphological criterion for taxonomic determination was the angle between the posterior part of the olecranon and the ridge on the volar edge of the ulna; this angle is smaller in alopex compared to vulpes; vtr. 255 is described as having an angle similar to that in alopex (fig. 6). gromova (pomoba 1950, 182) gave a more precise defi nition of this difference; this angle is < 140° in alopex, while in vulpes it is usually > 130°. measurements on a small sample of recent comparative material confi rm gromova’s observations; an alopex ulna has an angle of 138°, while two vulpes ulnae have angles of 150° and 160°. vtr. 255 has an angle of 150° and by this criterion is clearly from vulpes. turning to the cross-sectional morphology of the shaft, malez, following gromova (гpomoba, 1950, 182), suggested that in alopex the diaphysis is fl attened in the middle portion, while in vulpes the same portion is circular in cross section. furthermore, based on his own observations on recent material, malez (1963, 65) suggested that muscle attachments, in particular the crista interossea, are more developed in alopex than in vulpes. the diaphysis of vtr. 255 is circular in cross section, and thus more similar to vulpes than alopex. furthermore, our own observations on recent material indicate that the degree of development of muscle attachments is indicative of age at death and is not taxnomically indicative. metric analysis of the proximal end shows that, contrary to malez’s description, vtr. 255 is considerably larger than recent specimens of a. lagopus and that it instead falls well within the distribution of v. vulpes (fig. 7, tables 4–5). hence, on the basis of both morphological and metric comparisons, we have revised vtr. 255 from a. cf. lagopus to v. vulpes. vulpes vulpes material: layer d: left mandible with p1-m3 (vtr. 831/car), right metacarpal ii (vtr. 834/car), left metacarpal iii (vtr. 836/car), right metacarpal iv (vtr. 835), left femur shaft (vtr. 266); layer h: right upper c (vtr. 842/car), caudal vertebra (vtr. 837/car); layer i: right proximal radius (vtr. 265), left calcaneus (vtr. 832/car) fi gu re 6: revision of ulna (vtr. 255): a) vulpes vulpes, b) vtr. 255, c) alopex lagopus. comparative specimens are from zpgk. the arrow indicates the angle between the posterior part of the olecranon and the ridge on the volar edge of the ulna. fi gu re 7: fox proximal ulna dimensions (depth of the olecranon [dpa] against breadth across the coronoid process [bpc]) from veternica compared to recent comparative material of v. vulpes and a. lagopus. measurements as defi ned by driesch (1976). a. 1 cm b. c. geologia croatica 63/2geologia croatica 214 we confi rm the identifi cation of remains previously assigned to v. vulpes (malez, 1963, 66–70). to these we add a left proximal ulna from layer f (vtr. 255) that was previously identifi ed as a. cf. lagopus and a left metatarsal v from layer d/h/i (vtr. 262) that was previously identifi ed as felis lynx pardina (= lynx pardinus). measurements on these remains are presented in table 5. the mandible (vtr. 831/ car) is complete except for the coronoid process and the symphysis anterior to the canine alveolus; these parts are missing and appear to have been damaged at the time of excavation. the mandible is not otherwise modifi ed. the distal ends of ulna vtr. 255 and radius vtr. 265 appear to have been broken when the bones were still fresh. these breaks are smooth and spiral-shaped. these bones are not otherwise modifi ed. although the femur shaft (vtr. 266) suffered slight excavation damage to proximal and distal ends, there is evidence of light carnivore gnawing (shallow furrows and pitting) on the posterior side of the distal shaft and the distal end was probably removed by gnawing. the remainder of the remains are complete and do not show any surface modifi cations. 4.2.2. mustelidae mustela erminea material: layer h: left proximal tibia (vtr. 719/car); layer i: left innominate (vtr.720/car) we confi rm the identifi cations of m. erminea (malez, 1963, p. 76). the proximal tibia (vtr. 719) is slightly damaged on the posterio-lateral edge of the proximal articulation and the distal end has been removed by a recent break. the innominate (vtr. 720/car) has been broken on the shafts of the ilium and pubis. these remains are not otherwise modifi ed. mustela putorius material: layer d: left femur (vtr. 723/car); layer h: cranium with left p3–m1 and right p4–m1 (vtr. 721/car); layer i: left mandible with p2–m2 (vtr. 722/car), right femur missing proximal end (vtr. 724/car) we confi rm the identifi cations of m. putorius (malez, 1963, p. 76–81). the cranium (vtr. 721/car) is missing the occipital, left petrous, and most of the cranial base from an old break. the mandible (vtr. 722/car) is broken at the canine alveolus. the left femur (vtr. 723/car) is complete. the right femur (vtr. 724/car) is missing the proximal end on an old break. on both femora, localized patches of spongy bone have been exposed, probably from digestion by an owl. these remains are not otherwise modifi ed. martes martes material: layer h: right humerus (vtr. 717/car); layer i: left mandible with p3 and m1 (vtr. 716/car). we confi rm the assignment of the left mandible to m. martes on the basis of the relatively large distance (7.3 mm) between the two mandibular mental foramina (anderson 1970, p. 34; grundbacher 1992; malez, 1963, p. 81). the mandible (vtr. 716/car) shows minor post-depositional damage to the coronoid process and symphysis. the broken roots of the p2 are still in the alveoli. the mandible is not otherwise modifi ed. the humerus (vtr. 717/car) is complete and unmodifi ed. it is relatively long (gl = 70.4 mm) compared to its proximal depth (dp = 12.9) and distal breadth (bd = 15.1 mm, bt = 10.4 mm). a small recent sample of m. martes (n = 2) and m. foina (n = 3) humeri available in zagreb (zgpk) suggests that this bone is more gracile (longer relative to the depth/breadth of the articular ends) in m. martes than in m. foina. the relative dimensions of vtr. 717/car are more similar to m. martes than m. foina. the small size of our comparative sample and the absence of other diagnostic mortable 4: measurements on a proximal fox ulna from veternica (vtr.255) compared to recent specimens of a. lagopus (ummz; zpgk) and v. vulpes (cuclz; ummz; zpgk). alopex lagopus vulpes vulpes vtr. 255 mean range n mean range n bpc 9.6 9.0 8.6–9.5 4 10.1 8.7–11.2 17 dpa 15.3 13.4 12.7–13.8 4 15.7 14.4–17.6 17 table 5: measurements on remains identifi ed to v. vulpes from veternica. all measurements as defi ned in driesch (1976); numbers in parentheses for mandibular measurements refer to driesch (1976, fi g. 23a). # layer element (8) (10) (11) (19) (20) vtr. 831/car d mandible 58.7 27.2 32.8 13.6 12.0 # layer element l b vtr. 842/car h upper c 6.4 4.3 vtr. 831/car d p3 8.8 3.6 vtr. 831/car d p4 9.5 4.2 vtr. 831/car d m1 15.6 5.9 vtr. 831/car d m2 8.3 5.7 # layer element bpc dpa sdo vtr. 255 f ulna 9.6 15.3 12.6 # layer element bp dp sd vtr. 265 i radius 12.4 7.8 8.4 vtr. 266 d femur 14.2 # layer element gl bd vtr. 834/car d metacarpal ii 45.7 6.9 vtr. 836/car d metacarpal iii 51.0 5.9 vtr. 835/car d metacarpal iv 45.8 6.8 vtr. 262 d, h, i metatarsal v 57.3 6.3 vtr. 832/car i calcaneus 34.8 (8) length of cheek teeth p1-m3 at alveoli (10) length of molar row at alveoli (11) length of premolar row at alveoli (19) height of mandible behind m1 on buccal side (20) height of mandible in front of p3 on buccal side miracle and brajković: the palaeoecological signifi cance of the pleistocene mammalian fauna from veternica cave, croatia... geologia croatica 215 phological features, however, prevent us from determining this humerus to species level with certainty. hence we assign this humerus to martes sp. martes foina material: layer d: cranium with left p2–m1 and right p2, p4–m1 (vtr. 718/car) we confi rm the identifi cation of cranium vtr. 718/car as m. foina on the basis of the orientation of the external auditory meatus, the form of the infraorbital foramen, the morphology of the p3, and the morphology of the m1 (hans & steiner, 1986; malez, 1963, p. 83–84). the cranium has suffered minor damage to the zygomatic processes and left occipital condyle, most likely at the time of excavation. the specimen is in excellent condition and is not otherwise modifi ed. gulo gulo material: layer f: left i3 (vtr. 267) and right i3 (vtr. 268) a right and a left upper third incisor were identifi ed by malez (1963, p. 85–86, pl. xvi, fi g. 3a–b) as wolverine (vtr. 267 and vtr. 268, both level f). it is worth noting that in the absence of recent comparative material, malez based this identifi cation on comparisons with photographs from the palaeontological literature. malez (1963, 85) observed that both teeth were worn to an equal degree, and that given their similar dimensions, that they probably came from the same individual. our measurements at the crown base of length (mesial-distal) and breadth (buccal-lingual) are somewhat greater than those reported by malez (table 6). these dimensions are almost identical to those of a recent female wolf (fig. 8); wolf i3 appear to be elongated mesio-distally compared to wolverine. the morphology of vtr. 267 and vtr. 268 is also closer to comparative specimens of wolf than wolverine. the cingulum is more pronounced in wolverine than wolf, forming a distinct bulge on the mesial-buccal side of the tooth (fig. 9; döppes, 2001, fi g. 9). the axis of the crown (a tangent joining the mesial and distal ridges) is oriented anteriorposteriorly in alignment with the canine in wolf, whereas in wolverine the axis of the crown is oriented medial-laterally in alignment with the other upper incisors (fig. 9). in wolf, the root has a triangular cross section and is relatively larger relative to the crown, whereas in wolverine the root has an oval cross section and is relatively small relative to the crown. in all of these characters vtr. 267 and vtr. 268 are similar to wolf and different from wolverine. meles meles material: layer d: cranium with left i2, upper c, p4 and right p4–m1 (vtr. 726/car), maxilla with m1 (vtr. 730/car), right mandible with i2–m2 (vtr. 723/car), left mandible table 6: measurements on i3 from veternica compared to recent specimens of canis lupus, c. familiaris, gulo gulo, and fossil remains of c. lupus from šandalja and velika pećina. specimens l min–max (n) b min–max (n) vtr. 267 7.1 8.8 vtr. 268 7.0 8.8 canis lupus, male 7.6 7.6 (2) 10.05 9.9–10.2 (2) canis lupus, female 7.05 7–7.1 (2) 9.0 8.9–9.1 (2) canis lupus, fossil 8.34 7.7–9.4 (5) 10.72 10.2–11.3 (5) canis familiaris 6.5 6–7 (2) 8.45 7.6–9.3 (2) gulo gulo 5.1 8.5 fi gu re 8: i3 mesial-distal length vs. buccal-lingual breadth (both measured at crown base) in vtr. 267, 268 compared to recent specimens of canis lupus (zpgk), c. familiaris (zpgk), gulo gulo (cumz), and fossil specimens of c. lupus from šandalja and velika pećina. fi gu re 9: revision of i3 (vtr. 267): a) c. lupus, b) vtr. 267, c) g. gulo. a. 1 cm b. c. geologia croatica 63/2geologia croatica 216 with lower c, p4–m2 (vtr. 727/car), left articular condyle of a mandible (vtr. 728/car), atlas (vtr. 731/car), right humerus (vtr. 733/car), right ulna (vtr. 734/car), right radius (vtr. 735/car), left femur (vtr. 738/car), two right tibiae (vtr. 736/car and vtr. 737/car), left calcaneus (vtr. 739/car); layer i: left proximal humerus (vtr. 740/car), left ulna (vtr. 741/car) we confi rm the identifi cations of m. meles by malez (1963, p. 86–92), with the exception of the left proximal humerus from layer i (vtr. 740), which we have reassigned to f. silvestris. to the badger remains we have added a left distal tibia from layer d (vtr. 260) that was originally identifi ed as f. lynx pardina (malez, 1963, p. 97). starting with the proximal humerus (vtr. 740/car), although the greater tubercle is damaged on the specimen, it is much less developed than is the case in m. meles. as a result, the proximal end is relatively narrower (medial-lateral) relative to its depth (anterior-posterior). finally, the extension of the deltoid crest onto the lateral surface of the proximal shaft is much less pronounced in vtr. 740/car than is the case in m. meles; this situation is much closer to the case in f. silvestris (fig. 10). we conclude that vtr. 740/car is from a wild cat, although it is considerably larger than recent specimens. as discussed in greater detail below, the large size of pleistocene wild cat remains from veternica fi ts the pattern observed by kurtén (1965, p. 16) for pleistocene wild cats in europe and the levant. turning to the remains confi rmed as m. meles from layer d, the cranium (vtr. 726/car) is complete except for recent damage to the cranial base and occipital. the teeth are very heavily worn, indicating that the cranium came from a very old individual. the complete mandibles (vtr. 727/car and vtr. 729/car) are in excellent condition and are not otherwise modifi ed. wear on the m1 is moderate, suggesting that both mandibles came from prime-aged adults. the mandibles differ enough in size to indicate that they came from different individuals. the third mandibular fragment (vtr. 728/ car) preserves only the articular condyle; it was broken postdepositionally, possibly at the time of excavation. the atlas (vtr. 731/car) has suffered slight post-depositional damage to the wings, but is otherwise unmodifi ed. all of the long bones (vtr. 733, 734–738) are complete and unmodifi ed other than slight abrasion to some of the articular ends and two small cut marks on the medial shaft of tibia vtr. 736/ car. the calcaneus (vtr. 739) is complete and unmodifi ed. we confi rm the presence of badger in layer i from a single ulna (vtr. 741/car). other than very minor damage to the olecranon process, this bone is unmodifi ed. 4.2.3. felidae felis silvestris material: layer d: left femur (vtr. 264); layer h: right mandible with p3–m1 (vtr. 713/car), left proximal radius (vtr. 263); layer i: left lower c (vtr. 714/car), distal metapodial (vtr. 715/car) we confi rm the existing determinations of f. silvestris at veternica (malez, 1963, p. 94–96). to these we add the following elements revised from l. pardinus (malez, 1963, p. 96–97): a left distal humerus from layer i (vtr. 256), a right metatarsal ii from layer d (vtr. 261), a left proximal metatarsal iv from layer h (vtr. 257), a left metatarsal iv from layer h (vtr. 258), and a left proximal metatarsal iv from layer i (vtr. 259). we have also added a left proximal humerus from layer i (vtr. 740/car) revised from m. meles. we have also identifi ed as f. silvestris a distal metapodial without stratigraphic information (vtr. 715/ car). measurements are presented in table 7. the lower canine (vtr. 714/car) shows little wear; its tip is broken by a recent break. the mandible (vtr. 713/car) is complete except for slight excavation damage to the ascending ramus; it is not otherwise modifi ed. the distal humerus (vtr. 256) is broken near the mid-shaft; the edges of the break are in places rough and stepped and parts of the break appear to have followed existing fractures in the bone. this break thus appears to have been post depositional but prior to excavation. the radius (vtr. 263) is broken by a recent break near the distal end. the femur (vtr. 264) is complete. the metatarsal ii (vtr. 261) is complete. considering the fourth metatarsals, vtr. 257 is unbroken but missing an unfused distal epiphysis; vtr. 258 is complete, and vtr. 259 is broken mid-shaft by an old, transverse (dry bone) break. the distal metapodial fragment (vtr. 715/car) is broken near the distal end by an old, dry-bone break; although it is too incomplete to measure, it would have come from a largesized animal. none of the postcranial elements of wild cat have been otherwise modifi ed. fi gu re 10: revision of proximal humerus (vtr. 740/car): a) felis silvestris, b) vtr. 740/car, c) meles meles. comparative specimens are from zpgk. a. 2 cm b. c. miracle and brajković: the palaeoecological signifi cance of the pleistocene mammalian fauna from veternica cave, croatia... geologia croatica 217 lynx pardinus material: layer d: left distal tibia (vtr. 260); right metatarsal ii (vtr. 261); layer h: two left metatarsal iv (vtr. 257, vtr. 258); layer i: left distal humerus (vtr. 256); left metatarsal iv (vtr. 259); layer unspecifi ed (d/h/i): right metatarsal v (vtr. 262). felid remains from layers d, h, and i were identifi ed to the pardel or iberian lynx, l. pardinus, using the older nomenclature of felis lynx pardina (malez, 1963, p. 96–97). the distal humerus from layer i (vtr. 256) is in morphology clearly from a felid, and malez (1963, p. 96) identifi ed it to l. pardinus based on the morphological similarity of the specimen to the excellent illustrations of humeri identifi ed to f. (lynx) pardina (= lynx pardinus) from the sites of grottes de grimaldi (boule, 1910, p. 271–277, pls. xxxii–xxxiii) and grotte de l’observatoire (boule & de villeneuve, 1927, p. 78–80, pls. xvii–xviii). we are not aware of any morphological differences between wild cat and lynx; hence we rely on metric comparisons to identify the specimen. the humeri from grottes de grimaldi and grotte de l’observatoire are considerably larger than vtr. 256 (fig. 11). while the plot of greatest distal breadth (bd) against the breadth of the trochlea (bt) shows that vtr. 256 is larger than recent comparative material of f. silvestris and considerably smaller than recent material of lynx lynx, it clearly clusters with fossil representatives of f. silvestris from holocene (viktorjev spodmol) and pleistocene (šandalja ii) sites in the region (fig. 11). the left distal tibia (vtr. 260) has a recent break on the distal end (probably excavation damage) that removed the medial malleolus; hence it is not suitable for metric comparisons. nonetheless, its morphology is identical to recent badger (m. meles) tibiae and distinctly different from recent lynx tibiae in the comparative collections of zpgk (fig. 12). we have revised this specimen from l. pardinus to m. meles. the right metatarsal ii (vtr. 261) is in dimensions considerably smaller than the same bone identifi ed by boule to l. pardinus and larger than recent f. silvestris (fig. 13). the dimensions are very similar to a fossil specimen identifi ed by boule & de villeneuve (1927, p. 80) to african wild cat (f. ocreata), a taxon that is now accepted as a subspecies of f. silvestris (sunquist & sunquist, 2002, p. 84). hence we also have revised vtr. 261 to f. silvestris. of the three left metatarsal iv, one from layer h is complete (vtr. 258), while the other two preserve only the proximal end (vtr. 257 and vtr. 259). compared to recent fourth metatarsals, vtr. 258 is much smaller than lynx and larger than wild cat (fig. 14). given the very large size of other bones identifi ed to pleistocene forms of f. silvestris, we think that these fourth metatarsals are also most likely from f. silvestris. fossil forms of wild cat are reported to attain very large sizes, sometimes approaching that of a small lynx (argant, 1996, p. 214); hence in all of these cases we are confi dent that we are dealing with a large-sized wild cat and not with a small-sized lynx. the right metatarsal v (vtr. 262) is complete. its morphology is identical to red fox and disfi gu re 11: distal humerus breadth (bd) vs. breadth trochlea (bt) in vtr. 256 compared to recent specimens of f. silvestris and l. lynx (cumz and zpgk), and fossil specimens of f. silvestris (miracle, 1995; toškan & dirjec 2004; cassoli & tagliacozzo, 1994, 168) and lynx sp. (boule, 1910, pl. 32; boule & de villeneuve, 1927, pl. xviii; del campana, 1954, p. 42; bonifay, 1971, p. 271; clot & besson, 1974, p. 165; sarrión, 1978, p. 8; cassoli & tagliacozzo, 1994, 176). table 7: measurements on remains identifi ed to f. silvestris from veternica. all measurements as defi ned in driesch (1976); numbers in parentheses for mandibular measurements refer to driesch (1976, fi g. 24). # layer element (1) (5) (7) (8) (9) (10) vtr. 713/car h mandible 63.3 22.6 29.1 12.4 10.5 # layer element l b vtr. 714/car i lower c 6.0 4.7 vtr. 713/car h p3 vtr. 713/car h p4 7.3 2.9 vtr. 713/car h m1 8.5 3.9 # layer element gl bp dp dc bd bt sd vtr. 256 i humerus 26.9 18.5 11.2 vtr. 740/car i humerus 26.8 vtr. 263 h radius 9.2 5.3 6.0 vtr. 264 d femur 104.6 20.1 10.2 8.2 vtr. 261 d metatarsal ii 65.4 7.4 vtr. 257 h metatarsal iv 8.1 vtr. 258 h metatarsal iv 70.8 8.0 7.2 vtr. 259 i metatarsal iv 7.9 (1) total length = infradentale – condylar process (5) length of cheek teeth p3-m1 at alveoli (7) length of m1 at alveolus (8) height of the vertical ramus = basal point of angular process – coronion (9) height of mandible behind m1 on buccal side (10) height of mandible in front of p3 on buccal side geologia croatica 63/2geologia croatica 218 tinctly different from lynx fi fth metatarsals in the comparative collections of zpgk (fig. 15). the dimensions of this specimen show that it is much smaller than lynx and that it falls within the range of variation of recent representatives of red fox (fig. 16). morphological and metrical analyses support revising vtr. 262 from l. pardinus to v. vulpes. our revision of remains identifi ed to pardel lynx removes this taxon from the assemblage. the result is similar to a recent revision of similarly identifi ed canine teeth from parska golobina, slovenia (krofel et al., 2005). thus, there is no evidence that the range of the iberian lynx extended into southeastern europe during the pleistocene. in its place we have evidence for large-sized wild cats (table 7). this result does not come as a surprise as kurtén (1965, p. 16) observed over 40 years ago that “late pleistocene forms both in europe and palestine are much larger than their living descendants”. revision of the canid, mustelid, and felid remains from veternica thus removes a. lagopus, g. gulo, and l. pardinus from the fauna and increases the frequency of v. vulpes, canis sp., f. silvestris, and m. meles (table 8). as with the revision of the lagomorphs, these data have for the most part eliminated cold-adapted taxa and replaced them with taxa with a wider climatic tolerance. 5. discussion layer j at veternica probably dates to mis 5, and previous revision of the ungulate assemblages removed many “warmclimate” taxa from the assemblage (table 9, miracle & fi gu re 12: revision of distal tibia (vtr. 260): a) lynx lynx, b) vtr. 260, c) meles meles. comparative specimens are from zpgk. fi gu re 13: metatarsal ii greatest length (gl) vs. distal breadth (bd) of vtr. 261 compared to recent specimens of f. silvestris and l. lynx (cumz and zpgk), and fossil specimens of f. silvestris (boule & de villeneuve, 1927, pl. xviii; boessneck, 1978a, 1978b, 1978c; cassoli & tagliacozzo, 1994, 168) and lynx sp. (boule & de villeneuve, 1927, pl. xviii; clot & besson, 1974, p. 165; cassoli & tagliacozzo, 1994, 176). fi gu re 14: metatarsal iv greatest length (gl) vs. distal breadth (bd) of vtr. 258 compared to recent specimens of f. silvestris and l. lynx (cumz and zpgk), and fossil specimens of f. silvestris (boessneck, 1978b) and lynx sp. (clot & besson, 1974, p. 165). a. 1 cm b. c. miracle and brajković: the palaeoecological signifi cance of the pleistocene mammalian fauna from veternica cave, croatia... geologia croatica 219 brajković, 1992). the current revision does not further change the composition of the faunal assemblage beyond our observation that although malez (1963, p. 98) reported the presence of the cave lion, panthera spelaea, in layer j, none of the remains are so labeled. although it is likely that cave lion was present in layer j, we cannot verify this from the material. given that the cave lion is not indicative of particular palaeoenvironmental conditions, the issue of its presence or absence in layer j does not have an impact on our interpretations of the age and palaeoecological conditions in the region at the time of its deposition. the best comparisons to veternica layer j are krapina (miracle, 2007b), dated to mis 5e, and the lower layers (layer 13 and below, facies c) at divje babe i (toškan, 2007) that are thought to date to mis 5a–d (turk, 2007). all of the larger mammals present in veternica layer j are also present at krapina. the only differences are in the insectivores and rodents; erinaceus europaeus, talpa europaea, arvicola terrestris, microtus cf. agrestis, and hystrix cristata were found in veternica layer j (malez, 1963, table 33) and not at krapina (miracle, 2007b, p. 213). with the exception of the crested porcupine (h. cristata), the absence of these taxa at krapina can be explained by the recovery and curation biases against smaller-sized remains documented at krapina (miracle 2007b, p. 7–8). porcupine bones are comparable in size to the abundant beaver remains at krapina; they would have been recovered if they had been present. furthermore, the rarity of evidence of rodent gnawing at krapina (miracle 2007b, p. 237) suggests that porcupines were not active at the rockshelter. the contrast in porcupine representation between these sites is probably related to cave morphology and other local factors that infl uenced porcupine behavior instead of regional climates and/or age of deposition. the taxa present at veternica and missing from krapina are indicative of temperate to warm conditions; none of them are adapted to particularly cool or dry environments. the overall similarities between these assemblages suggest that they accumulated under rough ly comparable palaeoecological conditions. there are important differences between the larger mammal assemblages from veternica layer j and divje babe i facies c. present at veternica layer j and missing from divje babe facies c are castor fi ber, h. cristata, panthera pardus, stephanorhinus sp., s. scrofa, and bison priscus, while lepus sp., v. vulpes, m. martes, and rupicapra rupicapra are missing from veternica layer j and are present at divje table 8: revision of specimens identifi ed to alopex cf. lagopus, gulo gulo, and lynx pardinus. # element layer malez (1963) revised vtr. 255 ulna f a. cf. lagopus v. vulpes vtr. 267 i3 f g. gulo canis sp. vtr. 268 i3 f g. gulo canis sp. vtr. 740/car humerus i m. meles f. silvestris vtr. 256 humerus i l. pardinus f. silvestris vtr. 260 tibia d l. pardinus m. meles vtr. 261 metatarsal ii d l. pardinus f. silvestris vtr. 257 metatarsal iv h l. pardinus f. silvestris vtr. 258 metatarsal iv h l. pardinus f. silvestris vtr. 262 metatarsal v d/h/i l. pardinus v. vulpes fi gu re 15: revision of metatarsal v (vtr. 262): a) vulpes vulpes, b) vtr. 262, c) lynx lynx. comparative specimens are from zpgk. 1 cm b. c.a. fi gu re 16: metatarsal v greatest length (gl) vs. distal breadth (bd) of vtr. 262 compared to recent specimens of v. vulpes and l. lynx. compara tive specimens are from zpgk. geologia croatica 63/2geologia croatica 220 babe facies c (malez, 1963, table 33; toškan, 2007, table 11.14). the fi rst impression is that the veternica layer j fauna has more of a “full interglacial” (e.g. mis 5e) character than divje babe facies c owing to the presence of taxa including castor, hystrix, stephanorhinus, and sus. some of these contrasts, however, can be accounted for by the more open setting of veternica compared to divje babe. taxa like forest/prairie rhinoceros and bison might have preferred the wide valley of the sava on the edge of which veternica is situated, whereas chamois and pine marten may have favored the relatively steep and narrow idrijca valley in which divje babe is located. furthermore, all of these species were present in the region during both interglacial and glacial periods (miracle, 1991; miracle et al., 2010). the contrast in faunal composition between veternica layer j and divje babe i facies c probably refl ects local conditions and does not have further palaeoecological or chronstratigraphic importance. as we previously noted (miracle & brajković, 1992, p. 9) the sediments, pollen spectra, and faunal remains from veternica layer j indicate deposition under relatively warm and wet conditions, at least with regards to the rest of the sequence at veternica. we previously suggested dating layer j to sub-stages mis 5c or 5a (c. 100,000 and 80,000 ka, respectively) instead of the full interglacial conditions of mis 5e. although the further revision of the veternica fauna does not change the composition of the layer j assemblage, comparison to other sites in the region, in particular krapina, suggests that layer j could have also accumulated during mis 5e. layers g–i most probably date to mis 3 and 4; a 14c date of > 43,200 bp on a hearth from layer i confi rms layers i and j were deposited before c. 45,000 bp (miracle & brajković, 1992). the previous revision of the ungulate fauna removed megaloceros giganteus and alces alces from layer i, and bos primigenius from layers h and i. our recent analyses of the remainder of the mammal assemblage show that remains identifi ed as l. pardinus are from f. silvestris (table 9). these determinations are consistent with the remainder of the assemblage, which includes clethrionomys glareolus (layer i), arvicola terrestris, c. lupus, v. vulpes, m. erminea, m. putorius, m. meles (layer i), f. silvestris, p. spelaea, p. pardus (layer i), c. elaphus, c. capreolus, b. priscus (layer i), and r. rupicapra (layer h) (table 9; miracle et al., 2010). the disappearance of the crested porcupine (malez, 1963, table 33) and the appearance of elk in layer h correspond with a shift in sediment composition that may indicate relatively cooler and drier depositional conditions (miracle & brajković, 1992, p. 9). on the whole, the faunal assemblages from veternica layers h and i suggest deposition under temperate conditions with some forest cover and wetlands in the region. layer g at veternica contained only sporadic remains of cave bear near the contact with layer h (malez, 1963, p. 154); they were interspersed among a large quantity of rock rubble. this major roof collapse (malez, 1965, 207) probably occurred during a cooler period in mis 3, although another interpretation would be that layers h and i were deposited in mis 5 and layer g was deposited during mis 4. whatever the interpretation, the roof collapse in layer g probably closed the entrance to veternica, causing a major hiatus in cave use by hominins, bears, and other larger mammals. layers e and f are placed in mis 3 based on the disappearance of mousterian lithic artifacts alongside the continuing presence of a few undiagnostic stone tools. our previous revision confi rmed the presence of c. elaphus in both layers, c. capreolus and r. rupicapra in layer e, removed capra ibex from layer e, and added s. scrofa to layer e (miracle & brajković, 1992). the current revision replaces l. timidus with l. europaeus, ochotona sp. with lepus sp., a. lagopus with v. vulpes, and g. gulo with canis sp. we lack adequate comparative material to confi rm the identifi cation of a p1 to crocuta spelaea (malez, 1963, p. 92). we can confi rm the presence of p. spelaea in layer f, but not in layer e. the elimination of l. timidus, ochotona sp., a. lagopus, and g. gulo from layers e and f in conjunction with the addition of s. scrofa suggests at most cool to relatively temperate conditions during the deposition of these layers. therefore we cannot confi rm a signifi cant cold oscillation at veternica during the deposition of layers e and f as originally suggested by malez (1963, p. 151). turning to the wider region, the larger mammal assemblages from velika pećina and vindija also lack indicators of particularly cold conditions (miracle et al., 2010). although missing at veternica, we have confi rmed the presence of wolverine (velika pećina: layers f, g, i, k, and vindija: layer g upper) and steppe pika, o. pusilla, (vindija: layer g lower). wolverines may not be as reliable as indicators of cold climates as is commonly thought. in the recent past the range of wolverines extended as far south as northern germany and poland (krott, 1959, p. 14; nowak, 1991, p. 1124–1125), and this range has probably been reduced owing to competition from humans, wolves, and other competitors (krott, 1959, p. 96). finally, wolverines are reported to travel long distances in response to changing conditions (krott, 1959, p. 101; nowak, 1991, p. 1124–1125). turning to the wolverine fossils found at velika pećina and vindija, only a small number of remains from the head and extremities were found. these bones might have been still attached to pelts that had been transported relatively long distances by past people. for these reasons we are reluctant to use the presence of wolverines to infer very cold climatic conditions in the immediate region of veternica. the presence of steppe pika and other taxa adapted to relatively open environments suggests that at times such conditions were prevalent in the region. overall we reconstruct relatively temperate conditions with a range of environments present in the region. the deposition of layer d is assigned to mis 2 on the basis of a 14c date ca. 16,740 bp on overlying fl owstone from layer c8. the revision of the ungulate fauna removed ovis sp. 8 this and other radiocarbon dates have been calibrated using “online calpal” – quickcal2007 ver.1.5 (http://www.calpal-online.de/). miracle and brajković: the palaeoecological signifi cance of the pleistocene mammalian fauna from veternica cave, croatia... geologia croatica 221 from the assemblage and added bos/bison (miracle & brajković, 1992). the current revision of the lagomorphs and small carnivores confi rms the presence of lepus sp., c. lupus, v. vulpes, m. putorius, martes foina, m. meles, f. silvestris, removes l. pardinus from the assemblage, and replaces l. timidus with l. europaeus. many of these taxa (e.g. s. scrofa, c. capreolus, l. europaeus, and f. silvestris) are indicative of temperate conditions with some vegetative cover; none of them are indicative of particularly cold conditions. we can tentatively correlate veternica layer d with velika pećina layer d and vindija layer e (miracle et al., 2010). although not present at veternica, there is some evidence of the appearance of cold-adapted taxa at the other sites, in particular l. timidus in vindija layer e/f and rangifer tarandus in vindija layers e and e/f (miracle et al., 2010, table 3). while vindija provides some evidence of climatic deterioration with the onset of mis 2, these cold-climate indicators appear alongside taxa with wide tolerances and/or a preference for more temperate conditions (e.g. l. europaeus, v. vulpes, m. putorius, m. meles, f. silvestris, s. scrofa, c. elaphus, c. capreolus, and b. primigenius). this suite of taxa suggests that conditions were not particularly harsh or cold. this apparent mix of species with divergent climatic tolerances can also be explained by the close proximity of exposed, open alluvial plains and sheltered valleys in the region. such a juxtaposition of microhabitats would have provided a diversity of niches for local mammal populations. in any case, individual animals, not communities, populations, or species respond to climatic changes. hence, in the past as is the case today, faunal “communities” would have been in a constant state of fl ux. they would have been taken apart and reconstituted as animals (species) came and went through local processes of range shift, migration, and extirpation. 6. conclusions at veternica there is neither evidence of “cold-adapted” larger mammals like mountain hare, arctic fox, and wolverine nor of “steppe-adapted” animals like pika. our revision of the veternica faunal assemblages does not support an interpretation of signifi cant climatic oscillations during the deposition of layers associated with mis 2, 3, and 4. the absence of “cold-adapted” taxa suggests that either remains were deposited only during more temperate periods within mis 3 and 2 or that cold oscillations were not strongly expressed in northern croatia. the large mammal fauna is remarkably stable in composition over time; conditions in the region appear to have been broadly temperate. with rare exceptions (e.g. pika and reindeer at vindija), there is little evidence of a signifi cant immigration of larger mammals into the region during the upper pleistocene. a wide range of environments – open, forested, wetland, and rocky – were usually present in the area surrounding veternica. recent revision and study of the larger mammal and micromammal faunas from velika pećina and vindija supports this interpretation (miracle et al., 2010). there aren’t any dramatic or signifi cant changes in faunal composition over time with the exception of the appearance in vindija of a few “coldadapted” taxa associated with the onset of the last glacial maximum (mis 2) after about 27,000 bp. table 9: the revised pleistocene mammal assemblage from veternica cave. taxa added to the assemblage are indicated with a “+”, taxa confi rmed as present in the assemblage are indicated with a “√”, taxa removed from the assemblage are indicated with a “–”. taxa that could neither be confi rmed nor removed are indicated with a “?”. taxon n mis 2 mis 3 mis 3–4 mis 5 d e f g h i j lagomorha lepus timidus – – – lepus europaeus 10 + + + lepus sp. 22 + + √ √ ochotona sp. – carnivora canis lupus 146 √ √ √ √ √ √ canis sp. 5 + √ alopex lagopus – vulpes vulpes 18 √ + √ √ cuon alpinus 6 √ mustela erminea 2 √ √ mustela putorius 16 √ √ √ martes martes 3 – √ martes foina 9 √ martes sp. 1 + gulo gulo – meles meles 32 √ √ crocuta spelaea ? felis silvestris 12 √ √ √ lynx pardinus – – – panthera spelaea 53 – √ √ √ ? panthera pardus 12 √ √ ungulata stephanorhinus sp. 4 √ sus scrofa 24 √ + √ megaloceros giganteus – – dama cf. dama – cervus elaphus 156 √ √ √ √ √ √ alces alces 2 √ – capreolus capreolus 17 √ √ √ √ √ cervidae 3 – √ – √ √ bos primigenius – – – bison priscus 7 + + bos/bison 11 + + + + bovidae – capra ibex 3 √ – rupicapra rupicapra 10 √ √ + capridae 1 + ovis sp. – geologia croatica 63/2geologia croatica 222 thus, the croatian zagorje appears to have supported a fairly diverse and productive mammal fauna; this would have made it a favorable region for hominin settlement during mis 2–5. there is no evidence of signifi cant changes in faunal composition at the time of the middle palaeolithic-upper palaeolithic transition (ca. 40,000–30,000 ka, brajković & miracle, 2008). contrary to the suggestion that there was a “substantial evolution” in the mammalian faunas, which were “less stable [in]... slovenia and croatia where rather large changes in species composition occurred in the course of the same period” (musil, 2003, p. 182), our revision of the veternica mammal fauna shows stability and continuity in the assemblages over time. this apparent stability could be due to one or more of the following factors: a) hominins and other animals preferentially used specifi c sites or the region during warm phases, b) sedimentation and erosion have created a bias for warm phases, c) climatic oscillations in the region were less marked than previously thought, d) local factors of microclimate and topography buffered faunal communities from climatic oscillations, e) animals had wider temperature/precipitation tolerances than previously thought. explanation of this apparent stability in mammalian faunas requires further revision of existing assemblages and better control over chronology, formation processes, and other lines of palaeoecological evidence. references altuna, j. (2004): estudio biométrico de vulpes vulpes l y alopex lagopus l. contribucióen los yacimientos paleolíticos cantábricos.– munibe (antropologia-arkeologia), 56, san sebastian, 45–59. álvarez-lao, d.j. & garciá, n. (2010): chronological distribution of pleistocene cold-adapted large mammal faunas in the iberian peninsula.– quaternary international, 212, 120–128. anderson, e. (1970): quaternary evolution of the genus martes (carnivora, mustelidae).– acta zoologica fennica, 130, 1–132. argant, a. (1996): sous-famille des felinae.– in: guérin, c. & patou-mathis, m. (eds.): les grands mammifères plio-pléistocènes d’europe, masson, paris, 200–215. bennett, k.d., tzedakis, p.c. & willis, k.j. (1991): quaternary refugia of north european trees.– journal of biogeography, 18, 103–115. boessneck, j. (1978a): tierknochenfunde aus der mesolithischen kulturschicht unter dem felsdach inzigkofen im oberen donautal.– in: taute, w. (ed.): das mesolithikum in süddeutschland, teil 2: naturwissenschaftliche untersuchungen, archaeologica venatoria e. v., tübingen, 101–116. boessneck, j. (1978b): die tierknochenfunde aus der mesolithischen kulturschicht der falkensteinhöhle, markung thiergarten, im oberen donautal.– in: taute, w. (ed.): das mesolithikum in süddeutschland, teil 2: naturwissenschaftliche untersuchungen, archaeologica venatoria e. v., tübingen, 87–99. boessneck, j. (1978c): die tierknochenfunde aus den mesolithischen kulturschicht der jägerhaus-höhle, markung bronnen, im oberen donautal.– in: taute, w. (ed.): das mesolithikum in süddeutschland, teil 2: naturwissenschaftliche untersuchungen.– archaeologica venatoria e. v., tübingen, 77–86. bonifay, m. (1971): carnivores quaternaires du sud-est de la france.– mémoires du muséum national d’histoire naturelle, série c, 21, 1–373. bouchud, j. (1975): étude de la faune de l’abri pataud.– in: movius, h.l. (ed.): excavation of the abri pataud, les eyzies (dordogne), american school of prehistoric research, peabody museum, harvard university, bulletin 30, cambridge ma, 69–153. boule, m. (1910): les grottes du grimaldi.– géologie et paléontolo gie, tome 1, fascicule iv, imprimerie de monaco, monaco, 157–362. boule, m. & de villeneuve, l. (1927): la grotte de l’observatoire a monaco.– archives de l’institut de paléontologie humaine, memoire, 1, 1–113. božičević, s. (1995). postaja br.4. geološki vodič medvednice. [stop 4. geological guide of medvednica].– institut za geološka istra živanja, zagreb, p. 48. brajković, d. & miracle, p.t. (1995): revizija gornjopleistoceneske faune ungulata velike pećine (sz hrvatska) [revision of upper pleistocene ungulata fauna from velika pećina (nw croatia) – in croatian].– 1. hrvatski geološki kongres, opatija 18–21.10.1995., knj. saž., zagreb. p. 22. brajković, d. & miracle, p.t. (2008): middle palaeolithic and early upper palaeolithic subsistence practices at vindija cave, croatia.– in: darlas, a. & mihailović, d. (eds.): the palaeolithic of the balkans. bar international series 1819, archaeopress, oxford, 107–116. cassoli, p.f. & tagliacozzo, a. (1994): i macrommamiferi dei livelli tardo pleistocenici delle arene candide (savona, italia): considerazioni paleontologiche e archeologiche.– quaternaria nova, 4, 101–262. chaline, j. (1966): les lagomorphes et les rongeurs.– in: lavocat, r. & boubée, n. (eds.): faunes et flores préhistoriques de l’europe occidentale, paris, 397–440. clot, a. & besson, j-p. (1974): noveaux restes osseux de lynx dans les pyrénées.– bulletin de la société d’histoire naturelle de tuolouse, t. 110, fasc. 1–2, 156–169. corbet, g.b. (1966): the terrestrial mammals of western europe. foulis, london. 260 p. del campana, d. (1954): carnivori quaternari della tecchia e della caverna di equi nelle alpi apuane (mustelidi, canidi, felidi).– paleontographia italica, 44, 1–43. donard, e. (1981): “oryctolagus cuniculus” dans quelques gisements quaternaires français.– quaternaria, 23, 145–157. döppes, d. (2001): gulo gulo (mustelidae, mammalia) im jungpleistozän mitteleuropas.– beiträge zur paläontologie, 26, 1–95. driesch, a. (1976): a guide to the measurement of animal bones from archaeological sites. peabody museum bulletin 1, peabody museum of archaeology and ethnology, harvard university, cambridge ma, 134 p. frayer, d.w. (2006): the krapina neandertals. a comprehensive, centennial, illustrated bibliography. croatian natural history museum, zagreb. 219 p. gorjanović-kramberger, d. (1906): der diluviale mensch von krapina in kroatien: ein beitrag zur paläoantropologie.– in: kreidel c. w. (ed.): studien über die entwicklungsmechanik des primatenskelletes. wiesbaden, 59–277. гρomoвa, в. (1950): oпpеделитель млекопитающих ссср по костям скелета. вы.1, oпpеделитель по крупным труьчатым костям.– труды ком. по изуч. четверт. пер. академия наук ссср, москва, p. 182. grundbacher, b. (1992): nachweis des baummarders, martes martes, in der neolithischen ufersiedlung von twann (kanton bern, schweiz) sowie anmerkungen zur osteometrischen unterscheidung von martes martes und m. foina.– zeitschrift für säugetierkunde, 57, 201–210. guérin, c. & patou-mathis, m. (1996): les grandes mammifères plio-pléistocènes d’europe, masson, paris, 291 p. hans, m. & steiner, f.m. (1986): die nicht-metrische unterscheidmiracle and brajković: the palaeoecological signifi cance of the pleistocene mammalian fauna from veternica cave, croatia... geologia croatica 223 ung von schädeln mitteleuropäischer baumund steinmarder (martes martes and martes foina, mammalia).– annalen naturhistisches museum wien, serie b, 88/89, 267–280. hewitt, g. (2000): the genetic legacy of the quaternary ice ages.– nature, 405, 907–913. hillson, s. (2005): teeth, 2nd edition.– cambridge university press, 373 p. kahlke, r.-d. (1999): the history of the origin, evolution and dispersal of the late pleistocene mammuthus-coelodonta faunal complex in eurasia (large mammals). mammoth site of hot springs, rapid city sd, 219 p. koby, f.e. (1959): contribution au diagnostic ostéologique différentiel de lepus timidus linné et l. europaeus pallas.– verhandlungen des naturforschenden gesellschaft in basel, 70, 19–44. koby, f.e. (1960): contribution à la connaissance des lièvres fossiles, principalement de ceux de la dernière glaciation.– verhandlungen des naturforschenden gesellschaft in basel, 71, 149–173. krofel, m., pohar, v. & kos, i. (2005): o prisotnosti iberskega risa (lynx pardinus [temminck, 1872]) v mlajšem pleistocenu na območju slovenije. [presence of iberian lynx (lynx pardinus) temminck, 1872) in upper pleistocene in slovenia – in slovenian].– razprave iv. razreda slovenske akademije znanosti in umetnosti, 46, 83–95. krott, p. (1959): der vielfrass (gulo gulo l. 1758). monographien der wildsäugetiere, 13, gustav fischer verlag, jena, 159 p. kurtén, b. (1965): on the evolution of the european wild cat, felis silvestris schreber.– acta zoologica fennica, 111, 1–29. kurtén, b. (1968): pleistocene mammals of europe.– weidenfeld and nicolson, london, 317 p. malez, m. (1963): kvartarna fauna pećine veternice u medvednici [die quartäre fauna der höhle veternica (medvednica – kroatien) – in croatian].– palaeontologia jugoslavica, 5, 5–197. malez, m. (1965): pećina veternica u medvednici [die höhle veternica (medvednica-kroatien) – in croatian]. i. opći speleološki pregled. ii. stratigrafi ja kvartarnih taložina.– acta geologica, v, 175–237. malez, m. (1966): die gattung ochotona link, 1795 (lagomorpha brandt 1855) in jugoslawien.– bulletin scientifi que yougoslavie, section a, 11/1–2, 5–6. malez, m. (1968): ostaci zviždare u gornjem pleistocenu jugoslavije. [pfeifhasenreste aus dem oberen pleistozän in jugoslawien – in croatian].– geo loški vjesnik, 21, 147–156. malez, m. (1972): rasprostranjenost hladnodobnih životinja u gornjem pleistocenu jugoistočne evrope [über die verbreiteung kaltzeitlicher tiere im jungeren pleistozän südost-europas – in croatian].– rad jugoslavenske akademije znanosti i umjetnosti, 364, 133–180. malez, m. (1979a): prirodni okviri [natural frames].– in: basler, ð. (ed.): praistorija jugoslavenskih zemalja, i. svjetlost, sarajevo, 197–219. malez, m. (1979b): nalazišta paleolitskog i mezolitskog doba u hrvatskoj [palaeolithic and mesolithic sites in croatia – in croatian].– in: bas ler, ð. (ed.): praistorija jugoslavenskih zemalja, i. svjetlost, sarajevo, 227–276. malez, m. (1986): kvartarni sisavci (mammalia) iz velike pećine na ravnoj gori (sr hrvatska, jugoslavija) [säugetiere (mammalia) des quartärs aus velika pećina auf ravna gora (sr kroatien, jugoslawien) – in croatian].– rad zavoda za znanstveni rad jugoslavenske akademije znanosti i umjetnosti, varaždin, 1, 33–139. malez, m., smith, h.f., radovčić, j. & rukavina, d. (1980): upper pleistocene hominids from vindija cave, croatia, yugoslavia.– current anthropology, 21, 365–367. malez, m. & rukavina, d. (1979): položaj naslaga spilje vindije u sustavu članjenja kvartara šireg područja alpa [lage der hölenablagerungen von vindija im system der quartären vollgliederung des alpengebietes – in croatian].– rad jugoslavenske akademije znanosti i umjetnosti, 383, 187–218. miracle, p. (1991): carnivore dens or carnivore hunts?– rad hrvatske akademije znanosti i umjetnosti, 458, 193–219. miracle, p.t. (1995): broad-spectrum adaptations re-examined: hunter-gatherer responses to late-glacial environmental changes in the eastern adriatic.– umi, ann arbor, mi, 577 p. miracle, p.t. (1996): diversifi cation in epipalaeolithic subsistence strategies along the eastern adriatic coast: a simulation approach applied to zooarchaeological assemblages.– atti del museo civico di storia naturale, trieste ix (1994–1995), 33–62. miracle, p. (2007a): the late glacial ‘great adriatic plain’: ‘garden of eden’ or ‘no man’s land’ during the epipalaeolithic? a view from istria (croatia).– in: whallon, r. (ed.): late palaeolithic environments and cultural relations around the adriatic. bar international series 1716, archaeopress, oxford, 41–51. miracle, p.t. (2007b): the krapina palaeolithic site: zooarchaeology, taphonomy, and catalog of the faunal remains. croatian natural history museum, zagreb, 345 p. miracle, p.t. & brajković, d. (1992): revision of the ungulate fauna and upper pleistocene stratigraphy of veternica cave (nw croatia).– geologia croatica, 45, 1–14. miracle, p.t., mauch lenardić, j., brajković, d. (2010): last glacial climates, “refugia”, and faunal change in southeastern europe: mammalian assemblages from veternica, velika pećina, and vindija caves (croatia).– quaternary international, 212, 137–148. musil, r. (2003): the middle and upper palaeolithic game suite in central and southeastern europe.– in: andel, t.h. van & davies, w. (eds.): neanderthals and modern humans in the european landscape during the last glaciation: archaeological results of the stage 3 project. mcdonald institute for archaeological research, cambridge, 167–190. nowak, r.m. (1991): walker’s mammals of the world, 5th edition.– johns hopkins university press baltimore, 1629 p. poplin, f. (1976): les grands vertébrés de gönnersdorf fouilles 1968.– in: bosinski, g. (ed.): der magdalénien-fundplatz gönnersdorf, band 2, steiner, wiesbaden, 1–212. rakovec, i. (1959): kvartarna sesalska favna iz betalovega spodmola pri postojni [quaternary mammal fauna in betalov spodmol at postojna – in slovenian].– razprave iv razreda slovenske akademije znanosti in umetnosti, 5, 287–348. sala, b., masini, f., ficcarelli, g., rook, l. & torre, d. (1992): mammal dispersal events in the middle and late pleistocene of italy and western europe.– courier forschungsinstitut senckenberg, 153, 59–68. sommer, r.s. & nadachowski, a. (2006): glacial refugia of mammals in europe: evidence from fossil records.– mammal review, 36, 251–265. sarrión, i. (1978): un lince de las cavernas en la cueva del puerto (calasparra-murcia).– lapiaz, no 2, valencia, 7–26. stampfli, h.r. (1983): die grossen säugetiere und das schneehuhn als mögliche jagdfauna.– in: stampfli, h.r. (ed.): rislisberghöhle, band i. academica helvetica, 4, 37–67. suárez, e. m. & mein, p. (2004): the late pliocene locality of saintvallier (dróme, france). eleven micromammals.– geobios, 37, s115–s125. sunquist, m. & sunquist, f. (2002): wild cats of the world.– university of chicago press, chicago, 452 p. taberlet, p., fumagalli, l., wust-saucy, a.-g. & cosson, j.-f. (1998): comperative phylogeography and postglacial colonization routes in europe.– molecular ecology, 7, 453–464. toškan, b. (2007): ostanki velikih sesalcev iz divjih bab i. stratigrafi ja, taksonomija in biometrija [remains of large mammals from divje babe i. stratigraphy, taxonomy and biometry – in slovenian].– in: turk, i. (ed.): divje babe i: paleolitsko najdišče mlajšega geologia croatica 63/2geologia croatica 224 pleistocena v sloveniji. i. del: geologija in paleontologija [divje babe i: upper pleistocene palaeolithic site in slovenia. part i: geology and palaeontology – in slovenian], zrc sazu, inštitut za arheologijo, založba zrc, ljubljana, 357–367. toškan, b. & dirjec, j. (2004): ostanki velikih sesalcev iz viktorjevega spodmola [remains of large mammals in viktorjev spodmol. – in slovenian].– in: turk, i. (ed.): viktorjev spodmol in mala triglavca. prispevek k mezolitiku slovenije [viktorjev spodmol and mala triglavca. contribution to the mesolithic period in slovenia], opera instituti archaeologici sloveniae, 9, ljubljana, 135–167. turk, i. (2007): kronologija najdišča divje babe i [chronology of the divje babe i – in slovenian].– in: turk, i. (ed.): divje babe i: paleolitsko najdišče mlajšega pleistocena v sloveniji. i. del: geologija in paleontologija [divje babe i: upper pleistocene palaeolithic site in slovenia. part i: geology and palaeontology], zrc sazu, inštitut za arheologijo, založba zrc, ljubljana, 159–165. vuković, s. (1954): istraživanje pretpećinskog terena vindije [excavations in the area in front of vindija cave – in croatian].– speleolog, 2/1, zagreb, 23–28. willis, k.j. & van andel, t.h. (2004): trees or no trees? the environments of central and eastern europe during the last glaciation.– quaternary science reviews, 23, 2369–2387. manuscript received july 11, 2009 revised manuscript accepted january 10, 2010 available online june 28, 2010 geo.cro.2-3-61-kb.pdf 51 � not many geological or palaeontological disciplines in croatia have achieved such internationally relevant results as investigations on fossil calcareous algae. merit for that goes to some prominent international and croatian scientists who have also left their mark in other geological disciplines, not only in fossil algal research. this research was possible due the presence of the fascinating croatian dinaride mountains with their karst relief, and thick sequences of shallow-water carbonates, ranging from the late permian to the eocene, that contain a rich and various fl ora of calcareous benthic algae. investigations on fossil algae in croatia can be traced back to 1907 and the fi rst ever description of a permian dasyclad alga by the austrian geologist and palaeontologist richard johann schubert (1876–1915; biography in ampferer, 1915). croatia was at that time, part of the austrohungarian monarchy, so several austrian geologists undertook investigations in this area. schubert (1907) described his climb in 1905 to southern velebit mt., through the torrent of “mala paklenica”, across “ivine vodice” into the “velika paklenica” torrent, where above the hamlet of ramići, within dark calcareous slates and limestones, he found spherical forms with a “rich facetted” surface, and recognised them as belonging to a dasycladacean algae, comparable to the silurian rhabdoporella and recent bornetella. he named these spherical forms mizzia. he also found a gymnocodiacean alga “gyroporella” bellerophontis rothpletz, latterly known as gymnocodium, besides fusulinid foraminifera. he discovered a new algal (?) genus stolleyella, that pia (1920) detertonći grgasović ab stra ct investigations of fossil algae in croatia began in 1907 with the very fi rst description of the permian dasyclad mizzia velebitana from mt. velebit by austrian geologist richard schubert. this was followed by julius pia’s investigations (1920, 1925), on material given to him by schubert. the fi rst croatian researcher on fossil algae was milan herak, pia’s phd student, with his fi rst paper on ladinian dasyclads published in 1950. he cooperated with a colleague from the faculty of science, vanda kochansky-devidé, who published her fi rst papers together with herak on permian and carboniferous dasyclads in 1959 and 1960. while herak focused on triassic algae, kochansky-devidé investigated mostly upper palaeozoic algae and fusulinid foraminifera. ivan gušić comes from the same faculty, and his fi rst paper was published in 1966. momčilo milanović, from the institute of geology (the present day croatian geological survey), published his fi rst paper in 1962, focusing mainly on permian algae. the most prolifi c researcher branko sokač also came from the institute of geology; his fi rst papers dated from 1964, and he is still an active researcher. over time, papers originating from the “zagreb algological school” become distinguished by rich and well illustrated fossil material, making numerous contributions to the better understanding of fossil benthic algae from younger palaeozoic and mesozoic strata. this was possible not only because of the diligence of the authors, but was also the result of the very thick and well exposed carbonate sequence of the croatian dinarides mts. rajka radoičić from beograd (serbia) also described some taxa from croatia. almost all the research refers to dasycladal algae, while other algae are only rarely investigated. complete references to all papers are given. keywor ds: history of investigations, fossil algae, calcareous algae, croatia croatian geological survey, sachsova 2, hr-10000 zagreb, croatia; (tgrgasovic@hgi-cgs.hr) history of investigations on fossil algae in croatia geologia croatica 61/2–3 51–72 15 figs. zagreb 2008 geologia croaticageologia croatica � geologia croatica geologia croatica 61/2–3 52 mined to be a synonym of the previously known genus vermiporella. schubert determined the upper carboniferous age of the strata based on foraminifera, especially the species neoschwagerina craticulifera schwager, later confi rmed to be the guide fossil for the middle permian (kochansky & herak, 1960; sremac, 1991). valid description of the new genus and species mizzia velebitana (fig. 1) with illustrations, was soon given by schubert (1909). schubert was thorough investigator of the croatian dinarides. his most important works are the geological maps of dalmatia and numerous published papers, especially those on the geology of dalmatia, most of them published by the vienna “geologischen reichsanstalt”. he was one of the fi rst micropalaeontologists with signifi cant infl uence on the research of foraminifera. schubert gave some of the samples he gathered on velebit mt. to a young austrian geologist who later became the most famous researcher on fossil algae – julius von pia (fig. 2). pia thanked schubert for his help in his dissertation (pia, 1912). it is interesting that pia (1920, p. 6) states that the samples he received from velebit were collected not only by schubert but also by dragutin gorjanović kramberger, the most famous croatian geologist and internationally known explorer of the krapina neanderthal men, probably during his short investigation of velebit (gorjanović-kramberger, 1900). pia (1920) in his most famous and most cited paper describes specimens from the velebit mt. in detail: – diplopora annulata var. dolomitica forma vesiculifera (now kantia dolomitica) with typical specimens from the crnopac area north of gračac (probably on the gračac – obrovac road), obrovac – mali alan – sv. rok road and from the velika strana (locality unknown); – diplopora annulata var. dolomitica forma trichophora (now diplopora annulata) from the crnopac area, north of gračac and obrovac – mali alan – sv. rok road; – teutloporella vicentina from the velika strana (locality unknown); – mizzia velebitana, mizzia cf. yabei and vermiporella velebitana from paklenica, schubert’s original locality. pia (1925) once more illustrates and describes diplopora annulata var. dolomitica from the mali alan area (see grgasović, 2007). julius von pia (1887–1943) set the foundations of fossil algae research, primarily due to his capability and scrutinity. in addition, he had access to samples from the entire territory of the monarchy. pia’s biography was published by hoffmann (1993). the impact of his work is still important today, and he also had a direct encouraging infl uence on the research done in croatia. after the beginning of world war ii, the young croatian scientist, milan herak (fig. 3) came to pia in vienna in 1942, to study under his supervision. there, herak studied triassic sponges for his dissertation (herak 1943, 1944), which he fi nished at zagreb university. it is interesting to note that the sponge genus oligoplagia which he established there, later turned out to be a gymnocodiacean alga (roux, 1991). unsurprisingly, pia showed herak not only sponges but also some samples of fossil algae, noting that they deserve attention, especially since herak came from the area of the dinarides, rich in the fossil algae. unfortunately, pia’s entire collection wasn’t available at the time since it had been moved to the natural history museum in basel (switzerland). many years later, herak did get a chance to study the collection (kochansky & herak, 1960, p. 66) which, as he himself said, helped him in his later research. fi gu re 1: mizzia velebitana schubert 1909, fi rst described permian dasyclad from paklenica, velebit mt., croatia. fi gu re 2: julius von pia (1887–1943) – pioneer of the investigation on fossil calcareous algae (from hofmann, 1993). geologia croatica 53 tonći grgasović: history of investigations on fossil algae in croatia although contact with pia was encouragement to research fossil algae, it wasn’t herak’s fi rst encounter with these organisms. during study at zagreb university, he and vanda kochansky, along with some other colleagues, helped prof. marijan salopek in research of the palaeozoic strata in lika and velebit mt. salopek, in his papers, repeatedly quoted dasyclad algae, but only as guide fossils and with no illustrations. in his papers (salopek, 1942, 1952) he thanked his students and among them herak and kochansky for the help. herak (pers. comm.) remembers that at the end of 1939 or at the beginning of 1940 he was given an assignment to determine the samples of palaeozoic calcareous algae with basic instructions from colleague vanda kochansky who was a little bit more experienced. from salopek’s acknowledgments one can conclude that samples from the baške oštarije area (salopek, 1942) were determined by herak and kochansky, and the ones from paklenica (salopek, 1952) by kochansky. it is hard to briefl y describe the opulent career of prof. herak (biography in gušić & kranjec, 1997; sokač et al., 1997; koch & grgasović, 1997; benić et al., 1997; bahun & biondić, 1997). he was born in 1917 in brašlje vica village on žumberak mt., west of zagreb, and worked in the geological-palaeontological museum, technical museum and longest at the faculty of science in zagreb. he became an associate member of the yugoslav (today croatian) academy of arts and sciences in 1963 and a full member in 1973. along with palaeontology, (besides sponges and fossil algae, he also investigated the cave bear), he was also very successful in stratigraphy, regional geology, geotectonics and karst hydrogeology. he tried to combine these disciplines, leaving in each of them disciples to continue his work. as he himself says, his entire life has been connected to karst. his fi rst algal research paper about ladinian dasycladacea and their stratigraphic relevance, (herak, 1950) was based mainly on the material he had found in the geological – palaeontological museum that had been collected mostly by marijan salopek and partly by a prominent geologist and speleologist josip poljak. most of herak’s palaeontological papers deal with triassic algae. among the important ones are the papers on the genus diplopora (herak, 1957) and the genus physoporella (herak, 1958), as well as papers on the application of fossil algae in stratigraphy (herak, 1950, 1956, 1965a,b), and presentations at international conferences (herak, 1960; herak et al., 1967). his course book in palaeobotany, (herak, 1953, 1963), with a large chapter on calcareous algae, is particularly important and has introduced these fossils to generations of geology and biology students. prof. herak, although retired, is still active, being focused on geotectonic interpretations and also studying the history of geological research in croatia. vanda kochansky-devidé (1915–1990; figs. 4–5) worked with herak in the geological – palaeontological department of the faculty of science in zagreb and her entire career was dedicated to her greatest affection: palaeontology (biography in polšak et al., 1990). she began her career as prof. salopek’s assistant and her interests included various fossil groups, among them the miocene molluscs, cretaceous and fi gu re 3: milan herak (in sixties). fi gu re 4: vanda kochansky-devidé (1915–1990). fi gu re 5: vanda kochansky-devidé at fi eld class with her students. at the right is jasenka sremac. geologia croatica geologia croatica 61/2–3 54 eocene corals, palaeofl ora, palaeozoic calcareous algae and especially foraminifera, most of all upper palaeozoic fusulinids. she also dealt with popularization of geology and edited scientifi c journals, this very one you are reading among them. she became a full member of the croatian academy of arts and sciences in 1973 as one of the rare women. her fi rst papers on fossil algae were published together with herak (herak & kochansky 1959, 1960; kochansky & herak, 1960). in contrast to him, she dedicated her research to the palaeozoic algae. besides those mentioned above, her important papers are on the genus velebitella (kochanskydevidé, 1964), physoporella (kochansky-devidé, 1967), connexia (kochansky-devidé, 1979) and the velebit mt. carboniferous calcareous algae (kochanskydevidé, 1970). milan herak and vanda kochansky-devidé, primarily due to their ability and methodical approach to research, but also due to the infl uence of their mentors, became the founders of what is called the “zagreb algological school”. the research of croatian authors has become recognizable for an abundant and well illustrated fossil material and numerous contributions to the knowledge on upper palaeozoic and mesozoic fossil algae. scientists from this informal group developed rich correspondence with their colleagues from all over the world and participated in international meetings. this was neither common, nor simple in times when the world was divided into two blocks. professors herak and kochansky-devidé conveyed part of their knowledge to their students, and some of them continued to study fossil calcareous algae. ivan gušić (fig. 6) also worked as a professor at the same department (today it is the geological department), and for a short while at the institute of geology. prof. gušić was born in zagreb in 1938 and has been a member of the croatian academy since 1992. although his career is mainly connected to the mesozoic stratigraphy of the croatian dinarides, at the beginning of his career he researched benthic foraminifera along with fossil algae. he wrote his fi rst papers on the macroporella-pianellasalpingoporella group (gušić, 1966, 1969). herak, kochansky & gušić (1977) published their famous paper “the development of the dasyclad algae through the ages” in a book edited by erik flügel which contains papers from the fi rst symposium on fossil algae when the “international fossil algae association” was founded. herak and gušić participated in that symposium and discussed relevant issues in taxonomy and dasyclad algae evolution with members of “the french group of fossil algae researchers” (“groupe français d’étude des algues fossiles”) and other scientists. prof. jasenka sremac (fig. 5) began her career as prof. kochansky’s assistant, and her investigations focused on stratigraphy, palaeoecology and palaeontology of permian strata of the outer dinarides. she described fossil algae as important guide and palaeoenvironmental fossils (sremac, 1991). the institute of geology, now called the croatian geological survey, was founded in 1909 by, the already menfi gu re 6: ivan gušić fi gu re 7: momčilo milanović (1925–1998) fi gu re 8: branko sokač. geologia croatica 55 tonći grgasović: history of investigations on fossil algae in croatia tioned, dragutin gorjanović-kramberger, under the name “geological commission for the kingdom of croatia and slavonia”. although research in algae started in the faculty of science, it was extended at the institute. the initiation of the immense project of preparation of the “basic geological map1:100.000” of the former yu goslavia provided impetus to the research on the algal fl ora, as well as on other microfossils. research in the area of the karst dinarides, poor in macrofossils and lithologically homogenous, imposed the use of microfossils for stratigraphic division. during the decades of work, the abundant material has been collected and analyzed. application of benthic algae and foraminifera in stratigraphy turned out to be a very important tool in geological research. several researchers on fossil algae have been working in the institute of geology. one of the fi rst detailed investigations of the microfossil assemblages with the aim of stratigraphic division of jurassic and cretaceous deposits was performed by anić (1962) on the east biokovo mt. momčilo milanović (fig. 7) was born in 1925 in the village of bačina, near jagodina in serbia, and died in 1998 in zagreb (biography in gušić, 1999). he did his diploma thesis with prof. kochansky who introduced him to fossil algae (kochansky-devidé & milanović, 1962), which were the main interest of his entire career. participating in investigations of the upper palaeozoic of velebit mt. and lika, he collected rich fossil material, that he studied during the following years. he mostly researched permian algae (milanović, 1965, 1966a, b, 1968, 1974, 1975). as a palaeozoic specialist, he also determined other microfossils and participated in palaeozoic research in the other parts of croatia (gorski kotar, hrvatsko zagorje, banovina). branko sokač (fig. 8) is the most productive croatian researcher on fossil algae and also worked at the institute. he was born in 1933 in tivat (montenegro). he has been a full member of the croatian academy of sciences and arts since 1992. in the beginning of his career he found his fi rst fossil algae in the triassic strata on the krndija mt. near orahovica (eastern croatia), that motivated him to became interested in that branch of palaeontology. he began to collect literature and make the fi rst determinations of microscopic samples for himself. sokač belongs to the generation of members of the institute of geology that started and fi nished the vast work on the basic geological map 1:100.000. during the 1960’s the intense geological investigations on velebit mt. began. ante ivanović in 1962 gathered a team (figs. 9–11) which mapped the obrovac sheet (ivanović et al., 1973, 1976), the gospić sheet (sokač et al., 1974, 1976b), a part of the udbina sheet (šušnjar et al., 1973; sokač et al., 1976a) and later the otočac sheet (velić et al., 1974; sokač et al., 1976c) and ogulin sheet (velić & sokač, 1981; velić et al., 1982). sokač became the leader of that team in 1963 and was followed by velić in 1966. the great signifi cance of microfossils for stratigraphic determination of individual geological units was recognized even in the beginning of the research, so it fi gu re 9: geologists from the institute of geology at dušice, mt.velebit, 1963 (from the left to the right): leon nikler, unknown, zdravko crikvenik, maks posavec, branko sokač (lying) and žarko majcen. fi gu re 10: geologists from the institute of geology during transport to dušice camp site, mt. velebit, 1963 (from the left to the right): zdravko crikvenik, ernest oreški, two unknown in the back, ante šušnjara, leon nikler (behind horse), branko sokač. fi gu re 11: ričice, lika, 1962–1963 (from the left to the right): mirko malez, driver lojz, branko sokač and ivo velić. geologia croatica geologia croatica 61/2–3 56 was arranged that sokač would do micropalaeontological analysis of the algae and leon nikler would analyze the foraminifera. this is the reason that almost all papers from the 60’s and the 70’s are signed by sokač & nikler and nikler & sokač (fi rst papers were sokač et al., 1964 and nikler et al., 1964). nikler (1932–1997) was less productive as a writer, and later in his career he completely turned away from palaeontology (biography in bošković & sokač, 1998). when ivo velić became interested in benthic foraminifera, it was the beginning of a cooperation between him and sokač (velić & sokač, 1974; velić & al., 1979), that set the foundations of the detailed biostratigraphy of the croatian dinarides, thus enabling its correlation to other countries. a majority of sokač’s papers deals with dasyclad algae which he has researched intensely and the only thing he has been dedicated to with so much passion is culinary. he has described a large number of new taxa from croatia, but also from the neighboring areas – bosnia and herzegovina and montenegro. he has always tried to base his descriptions on a large number of samples, richly document them with illustrations and he has mostly polished the microscopic slabs by himself. he has always taken into consideration his colleagues’ opinions and studied in detail the papers they sent him. sokač has been very critical of his own work and sometimes even opposes with arguments his earlier work in order to improve the knowledge of these tiny organisms that he has fi gu re 12: four generations of croatian researcher on fossil algae at the “9th international symposium on fossil algae” in zagreb, 2007 (from the left to the right): ivan gušić, milan herak, branko sokač and tonći grgasović. fi gu re 13: rajka radoičić from serbia (in sixties). fi gu re 14: participitants of the “9th international symposium on fossil algae” in zagreb, 2007. geologia croatica 57 tonći grgasović: history of investigations on fossil algae in croatia been so interested in. it is diffi cult to select some of his many pap ers, dealing with the triassic (sokač, 1968, 1974; sokač & grgasović, 1995, 1998), jurassic (nikler & sokač, 1965, 1967, 1968, 1970; sokač & nikler, 1966, 1969a,b, 1973b; sokač, 1988, 1992; sokač & velić, 1978a), and cretaceous (sokač, 1985, 1986, 1989, 1990, 1993, 2000, 2005; sokač & grgasović, 2004; sokač & jelaska, 1991; sokač & nikler, 1971, 1973a, 1975; sokač & velić, 1978b, 1980, 1981a,b,c, 1982, 1983). more recent ones that are extensive and a synthesis of his earlier research include sokač, (1987, 1996, 2001, 2004). the present author (fig. 12) also comes from the croatian geological survey. sokač instructed and enthused me in the art of fossil algal research, resulting mostly in work on the triassic strata of northwestern croatia (grgasović, 1997; grgasović et al., 2002). one should defi nitely mention rajka radoičić (fig. 13) from belgrade (serbia) who in her very productive career has also investigated fossil algae from croatia. in describing some new species she has used material collected in croatia, and some species have their type localities in croatia (radoičić, 1965, 1967, 2002). most of the papers from the list of references (see appendix) deal with dasyclad algae. some deal with gymnocodiacean algae and only a few with red coralline algae, mainly based on the material from the palaeocene (gušić, 1973; gušić & babić, 1973; babić et al., 1976; šikić, k. & šikić, l., 1978). upper badenian (miocene) deposits from croatia are rich in coralline fossils, but so far the only detailed research has been that in the explanatory notes of the geological maps and some papers of other geological disciplines. apart from the aforementioned authors, many other croatian researchers have investigated benthic algae, mostly as guide fossils in the construction of geological maps, in scientifi c papers, and in master’s or doctoral theses. although their contribution has been immense, it is not possible to mention them all, primarily due to the fact that someone might involuntarily be left out. let me mention also stjepko golubić from boston (usa) who has researched living as well as fossil cyanobacteria from all over the world, and although he is an american scientist he originates from croatia and was educated here (phd at zagreb university). this text names only the authors who have researched fossil benthic algae because this research has a long history. recently, there are colleagues dealing with fossil algal plankton but it seems too early to write about the history of such research. the “9th international symposium on fossil algae” was organized in croatia in 2007 (figs. 14–15) with fi eld trips to the dinarides and the northwestern croatia (grgasović & vlahović, 2007), celebrating 100 years of fossil algae research in croatia. species and genera that have been described from croatia, or by croatian authors: (* mark type species of the genus. if the type locality is not indicated, it is not a new taxon but only nov. comb.) richard johann schubert mizzia schubert, 1909 *mizzia velebitana schubert, 1909, emend. rezak, 1959 – middle permian, paklenica, velebit mt., croatia stolleyella schubert, 1909 [younger synonym of vermiporella stolley, 1893, after pia, 1920] *stolleyella velebitana schubert, 1909 [cf. vermiporella velebitana (schubert, 1909) pia, 1920] – middle permian, paklenica, velebit mt., croatia – problematic microfossil, affi liation to algae is not certain milan herak cayeuxia mediterranea herak, 1967 – cyanobacteria, jurassic, island of chios, greece diplopora annulata subsp. annulata (pia, 1920) herak, 1957 [= forma trichophora pia, 1920; = diplopora annulata (schafhäutl, 1853) 1863] diplopora annulata subsp. dolomitica herak, 1957 [= forma vesiculifera pia 1920; cf. kantia dolomitica pia, 1912, emend. güvenç, 1979] diplopora hexaster subsp. helvetica (pia, 1912) herak, 1965 [cf. poncetella helvetica (pia, 1912) güvenç, 1979] diplopora hexaster subsp. hexaster (pia, 1912) herak, 1965 [cf. poncetella hexaster (pia, 1912) güvenç, 1979] diplopora subtilis pia var. graeca herak, 1967 [cf. kantia? subtilis var. graeca (herak, 1967) güvenç, 1979] – anisian, island of chios, greece oligoporella chia herak, 1967 – ladinian, island of chios, greece physoporella croatica herak, 1958 [typifi cation in granier & deloffre, 1995] – anisian, environs of knin, croatia physoporella likana herak, 1965 [typifi cation in granier & deloffre, 1995] – middle triassic (? ladinian), sv. rok, lika, croatia physoporella minutoloidea herak, 1967 – anisian, island of chios, greece fi gu re 15: symposium logo. geologia croatica geologia croatica 61/2–3 58 milan herak and vanda kochansky-devidé anthracoporella vicina kochansky & herak, 1960 – carboniferous, okrožnik, vitanje, n celje, slovenia, with additional material from the carboniferous, brušane, velebit mt., croatia clavaporella kochansky & herak, 1960, emend. vachard, 1980 *clavaporella caliciformis kochansky & herak, 1960 – middle permian pebble from the anisian conglomerate, matković, nw bar, montenegro clavaporella conforma (endo, 1958) kochansky & herak, 1960, nom. nud. [= clavaphysoporella conforma endo, 1958, nom. nud.] clavaporella faceta (endo, 1958) kochansky & herak, 1960, nom. nud. [= clavaphysoporella faceta endo, 1958, nom. nud.] diplopora pusilla kochansky & herak, 1960 [cf. eovelebitella pusilla (kochansky & herak, 1960) vachard, 1974; = clavaporella pusilla (kochansky & herak, 1960) vachard, 1980] – middle permian pebble from the anisian conglomerate, matković, nw bar, montenegro epimastopora alpina kochansky & herak, 1960, nom. nud. [cf. epimastoporella alpina kochansky & herak ex roux 1979] – based on specimens from the lower permian, col mezzodě, forni avoltri, friuli-venezia giulia, italy from pia (1937), with additional material from the lower permian of jezersko, slovenia epimastopora likana kochansky & herak, 1960 [younger synonym of epimastoporella japonica (endo, 1951) roux, 1979, after mamet & roux in mamet et al., 1987] – lower permian, velebit mt., croatia mizzia cornuta kochansky & herak, 1960 – middle permian, environs of bar, montenegro, with additional material from the middle-upper permian, crne grede, velebit mt., croatia and middle permian, bohinjska bela, slovenia pseudoepimastopora kroatiaca homann, 1972, nom. nud. [synonym of epimastoporella japonica (endo, 1951) roux, 1979, after mamet & roux in mamet et al., 1987; cf. epimastoporella kroatiaca homann ex roux 1979] – based on specimens from the upper carboniferous, brušane, velebit mt., croatia from kochansky & herak (1960) vanda kochansky-devidé connexia kochansky-devidé, 1970 *connexia slovenica kochansky-devidé, 1979 – lower permian, ortnek, dolenjsko, slovenia, with additional material from karavanke mts. and julian alps mts., slovenia gyroporella intusannulata kochansky-devidé, 1970 – low er permian, gozd–martuljek, kranjska gora, slovenia physoporella leptotheca kochansky-devidé, 1967 – triassic (? upper anisian), železnica, gozd–martuljek, kranjska gora, slovenia velebitella kochansky-devidé, 1964 velebitella simplex kochansky-devidé, 1964 [cf. pseudovelebitella simplex (kochansky-devidé, 1964) mamet & roux, 1978] – lower permian, environs of sv. rok, lika, croatia, with additional material from the upper carboniferous, environs of medak, velebit mt., croatia *velebitella triplicata kochansky-devidé, 1964 – upper permian, egeljac – šilović, velebit mt., croatia momčilo milanović goniolinopsis milanović, 1966b, emend. mu, 1984 *goniolinopsis hexagona milanović, 1966b – lower permian, velebit mt., croatia hexaella milanović, 1989 *hexaella heraki milanović, 1989 – lower permian, gorski kotar, croatia – problematic microfossil, probably an alga kochanskyella milanović, 1974 *kochanskyella tulipa milanović, 1974 – lower permian, environs of gospić, velebit mt., croatia likanella milanović, 1966a [typifi cation in granier & deloffre, 1995] likanella minima milanović, 1986, nom. nud (no description and illustration). – lower permian, environs of mrzle vodice, gorski kotar, croatia *likanella spinosa milanović, 1966a [typifi cation in granier & deloffre, 1995] – middle–upper permian, velebitmt., croatia salopekiella milanović, 1965 [typifi cation in granier & deloffre, 1995] salopekiella breziki milanović, 1975, nom. nud. [cf. uragiellopsis breziki milanović ex vachard, 1980] – lower permian, environs of medak, velebit mt., croatia salopekiella? kochanskae milanović, 1968, nom. nud. [cf. clavaporella kochanskae milanović ex vachard, 1980] – lower permian, environs of medak, velebit mt., croatia *salopekiella velebitana milanović, 1965 [typifi cation in granier & deloffre, 1995] – middle–upper permian, environs of medak, velebit mt., croatia branko sokač biokoviella sokač, 2004 *biokoviella robusta (sokač, 1993) sokač, 2004 [= salpingoporella robusta sokač, 1993] – upper barremian, biokovo mt., croatia biokoviella gusici sokač, 2004 – upper barremian, biokovo mt., croatia clypeina caliciformis nikler & sokač, 1970 [typifi cation in granier & deloffre, 1993] – upper malmian, island of lastovo, croatia clypeina delmatarum sokač & velić, 1981a [cf. humiella delmatarum (sokač & velić, 1981a) sokač, 1987] – upper berriasian–valanginian, biokovo mt., croatia geologia croatica 59 tonći grgasović: history of investigations on fossil algae in croatia clypeina gigantea sokač, 1996 – lower barremian, island of mljet, croatia clypeina radici sokač, 1986 – neokomian, road slano–zavala, herzegovina, bosnia and herzegovina coniporella piriformis sokač & velić, 1981c [cf. humiella piriformis (sokač & velić, 1981c) granier & deloffre, 1993] – upper berriasian–valanginian, biokovo mt., croatia crinella sokač & nikler, 1973a [typifi cation in granier & deloffre, 1993] *crinella carsica sokač & nikler, 1973a [typifi cation in granier & deloffre, 1993] – barremian–aptian, environs of nikšić, montenegro cymopolia longistila sokač & nikler, 1971 [typifi cation in granier & deloffre, 1993] – lower cretaceous, environs of nikšić, montenegro cymopolia velici sokač & nikler, 1973a [typifi cation in granier & deloffre, 1993] – barremian-aptian, environs of nikšić, montenegro cylindroporella anici nikler & sokač, 1965, nom. nud. [cf. heteroporella anici (nikler & sokač, 1965) granier & deloffre, 1993] – upper jurassic, velebit mt., croatia cylindroporella bradarici sokač, 1990 [younger synonym of cylindroporella taurica conrad & varol, 1990] – albian, e ogulin, croatia dinarella sokač & nikler, 1969a *dinarella kochi sokač & nikler, 1969a – lower liassic, velebit mt., croatia euspondyloporella sokač & nikler, 1973a [young er synonym of triploporella (steinmann, 1880) barattolo, 1981, after granier & deloffre, 1993 – typifi cation] *euspondyloporella duplicata sokač & nikler, 1973a, nom.nud. [= triploporella duplicata (sokač & nikler, 1973a) granier & deloffre, 1993] – barremian-aptian, environs of nikšić, montenegro fanesella anae sokač, 1988 [cf. palaedasycladus anae (sokač, 1988) sokač, 2001; typifi cation in granier & deloffre, 1993] – lower liassic, velebit mt., croatia favoporella sokač, 1968 [? younger synonym of kantia pia, 1912, emend. güvenç, 1979] *favoporella annulata sokač, 1968 [? younger synonym of diplopora annulatissima pia, 1920, after ott, 1972;? cf. kantia monregalensis baretti, 1919] – upper anisian – lower ladinian, velebit mt., croatia griphoporella minima nikler & sokač, 1967 – oxfordian – kimeridgian gyroporella lukicae sokač & velić, 1982 – lower aptian, environs of jajce, bosnia and herzegovina helioporella sokač & nikler, 1973a [typifi cation in granier & deloffre, 1993] *helioporella cylindrica sokač & nikler, 1973a [typifi cation in granier & deloffre, 1993] – barremianaptian, environs of nikšić, montenegro humiella (sokač & velić, 1981a) sokač, 1987 humiella japodica sokač, 2001 – lower liassic, velebit mt., croatia humiella? pupnatensis sokač, 1987 – upper barremian – lower aptian, island of korčula, croatia humiella sardiniensis (ott & flaviani, 1983) sokač, 1987 [= lagenoporella sardiniensis ott & flaviani, 1983] *humiella teutae sokač & velić, 1981a [= humiella catenaeformis (sokač, & nikler, 1973a) granier & deloffre, 1993] – neocomian, s hercegovina, bosnia and herzegovina korkyrella sokač & velić ex sokač, 2004 korkyrella ivanovici sokač, 1987 nom. nud. [cf. cylindroporella ivanovici (sokač, 1987) masse & luperto-sinni, 1989, nom. nud.; synonym of korkyrella texana (johnson, 1965) sokač, 2004] – uppermost barremian – lower aptian, island of korčula, croatia *korkyrella texana (johnson, 1965) sokač, 2004 – based on specimens from the albian, usa from johnson (1965) with additional material from the dinaride mts., croatia linoporella kapelensis sokač & nikler, 1973b – tithonian, velika kapela mts., croatia linoporella svilajensis sokač & velić, 1976 – upper jurassic – lower cretaceous, svilaja mt., croatia linoporella vesiculifera sokač, 2005 – upper barremian, biokovo mt., croatia macroporella aptiensis sokač, 1989 [synonym of neomeris cretacea steinmann, 1899, after sokač, 2004] – lower aptian, grabrk, sw karlovac, croatia macroporella incerta sokač & nikler, 1973a [cf. salpingoporella incerta (sokač & nikler, 1973a) bassoullet et al., 1978; typifi cation in granier & deloffre, 1993] – barremian–aptian, environs of nikšić, montenegro macroporella verticillata sokač & nikler, 1973a[= salpingoporella verticillata (sokač & nikler, 1973a) bassoullet et al., 1978; synonym of salpingoporella incerta (sokač & nikler, 1973a) bassoullet et al., 1978, after sokač in granier & deloffre, 1993 – typifi cation] – barremian-aptian, environs of nikšić, montenegro montenegrella sokač & nikler, 1973a [typifi cation in granier & deloffre, 1993] montenegrella fustiformis sokač & nikler, 1973a, nom. nud. – barremian-aptian, environs of nikšić, mon tenegro *montenegrella tubifera sokač & nikler, 1973a [typifi cation in granier & deloffre, 1993] – barremianaptian, environs of nikšić, montenegro geologia croatica geologia croatica 61/2–3 60 montenegrella verae sokač & nikler, 1973a [synonym of montenegrella tubifera sokač & nikler after sokač in granier & deloffre, 1993 – typifi cation] – barremian-aptian, environs of nikšić, montenegro palaeodacycladus alanensis sokač, 2001 – lower liassic, mali alan pass, velebit mt., croatia palaeodacycladus astericus sokač, 2001 – lower liassic, mali alan pass, velebit mt., croatia palaeodacycladus benceki sokač, 2001 – lower liassic, mali alan pass, velebit mt., croatia palaeodacycladus dolomiticus (cros & lemoine, 1966) sokač, 2001[= fanesella dolomitica cros & lemoine, 1966] petrascula? heraki sokač & nikler, 1966 [cf. palaeodacycladus mediterraneus var. heraki (sokač & nikler, 1966) sokač, 2001] – lower liassic, velebit mt., croatia petrascula? illyrica sokač & nikler, 1966 [cf. palaeodacycladus mediterraneus var. illyricus (sokač & nikler, 1966) sokač, 2001] – lower liassic, velebit mt., croatia palaeodacycladus mediterraneus var calciticus sokač, 2001 – lower liassic, mali alan pass, velebit mt., croatia palaeodacycladus multiporus sokač, 2001 – lower liassic, mali alan pass, velebit mt., croatia piriferella sokač 1996 piriferella somalica (conrad, peybernes & masse, 1983) sokač, 1996 [= clypeina somalica conrad, peybernes & masse, 1983; = similiclypeina somalica (conrad, peybernes & masse, 1983) bucur, 1993] *piriferella spinosa sokač, 1996 – upper barremian, island of mljet, croatia praturlonella pejovicae (radoičić, 1969) sokač, 1996 [= clypeina pejovicae radoičić, 1975, non 1969; = likanella pejovicae (radoičić, 1969) bassoullet et al., 1978; = selliporella pejovicae (radoičić, 1969) sokač & velić, 1978a] salpingoporella biokovensis sokač & velić, 1980 – upper barremian, biokovo mt., croatia salpingoporella croatica sokač, 1992 – upper doggerian, osojnik, environs of dubrovnik, croatia salpingoporella donatae sokač, 2000 – upper coniacian – campanian, primošten, croatia salpingoporella heraldica sokač, 1996 – transition barremian-apian, island of korčula, croatia salpingoporella polygonalis sokač, 1996 – lower barremian, island of mljet, croatia salpingoporella polsaki sokač & jelaska, 1991 – middle? – upper cenomanian, island of brač, croatia salpingoporella robusta sokač, 1993 [cf. biokoviella robusta (sokač, 1993) sokač, 2004 ] – upper barremian, biokovo mt., croatia salpingoporella verrucosa sokač, 1996 – upper barremian, island of mljet, croatia selliporella dalmatica sokač & velić, 1978a [cf. praturlonella dalmatica (sokač & velić, 1978a) sokač, 1996; = “dasycladacea” dalmatica radoičić, 1968, nom. nud.; = verticilloporella dalmatica radoičić ex raviv & lorch 1970, nom. nud.] – upper barremian, island of korčula, croatia selliporella? problematica sokač, 2001 – lower liassic, mali alan pass, velebit mt., croatia tintinnopsella kapelensis velić & sokač, 1976 [synonym campbelliella striata (carozzi, 1954) radoičić, 1959c, emend. de castro, 1993] – tithonian, velika kapela mt., croatia trinocladus? niksici sokač & nikler, 1973a, nom. nud. – barremian-aptian, environs of nikšić, montenegro triploporella bacilliformis sokač, 1985 – lower aptian, island of korčula, croatia triploporella issaensis sokač & nikler, 1975 – aptian –?lower albian, island of vis, croatia triploporella marsicana praturlon, 1964 var. adriatica sokač & nikler, 1975 – aptian –?lower albian, island of vis, croatia triploporella marsicana praturlon, 1964 var. marsicana sokač & nikler, 1975 uragiella ragusina sokač, 1992 – upper doggerian, osojnik, environs of dubrovnik, croatia uragiella matzi sokač & velić, 1983 – upper cretaceous, primošten, croatia branko sokač and tonći grgasović asterocalculus sokač & grgasović, 1998 *asterocalculus heraki sokač & grgasović, 1998 – gymnocodiacean, rhaetian, žumberak mt., croatia dissocladella bystrickyi sokač & grgasović, 1995 – norian – rhaetian, gornje vrapče, medvednica mt., croatia megaporella nikleri sokač & grgasović, 2004 – upper barremian, biokovo mt., croatia scinderella grgasović & sokač, 2002 *scinderella scopuliformis grgasović & sokač, 2002 in grgasović et al., 2002 – anisian, belski dol, ivanščica mt., croatia ivan gušić clypeina croatica gušić in deloffre & radoičić, 1978 [= salopekiella inopinata gušić, 1967, nom. nud.] cymopolia heraki gušić, 1967 [? younger synonym of cymopolia mayaense johnson & kaska, 1965, after deloffre & radoičić, 1978] – middle maastrichtian, environs of jajce, bosnia and herzegovina macroporella (pianella) adriatica gušić, 1966 [cf. salpingoporella adriatica (gušić, 1966) conrad, praturlon & radoičić, 1973] – berriasian – valanginian, istria, croatia geologia croatica 61 tonći grgasović: history of investigations on fossil algae in croatia macroporella (pianella) istriana gušić, 1966 [cf. salpingoporella istriana (gušić, 1966) conrad, praturlon & radoičić, 1973] – berriasian – valanginian, istria, croatia salopekiella inopinata gušić, 1967, nom. nud. [cf. clypeina croatica gušić in deloffre & radoičić, 1978 – validisation and new name] – middle maastrichtian, environs of jajce, bosnia and herzegovina rajka radoičić actinoporella kukoci radoičić, 1974 [typifi cation in radoičić, 1975] – paleocene, island of korčula, croatia bacinella irregularis radoičić, 1959b – lower cretaceous, bačinska jezera, ploče, croatia – problematic microfossil, probably an alga “dasycladacea” dalmatica radoičić, 1968, nom. nud. [cf. praturlonella dalmatica (sokač & velić, 1978) sokač, 1996; = selliporella dalmatica sokač & velić, 1978; = verticilloporella dalmatica radoičić ex raviv & lorch, 1970, nom. nud.] – transition barremian-aptian, island of mljet, croatia pianella turgida radoičić, 1965, nom. nud. [cf. salpingoporella turgida radoičić, 1965; typifi cation in radoičić, 1975] – albian, island of mljet, croatia salpingoporella dinarica radoičić, 1959a – barremianaptian, environs of podgorica, montenegro, with additional material from bačinska jezera, ploče, croatia salpingoporella melitae radoičić, 1967 [typifi cation in radoičić, 1975] – upper barremian – lower aptian, island of mljet, croatia salpingoporella pasmanica radoičić, 2002 – middle campanian, island of pašman, croatia species and genera dedicated to the croatian authors: milan herak asterocalculus heraki sokač & grgasović, 1998 – gymnocodiacean, rhaetian, žumberak mt., croatia physoporella heraki bystrický, 1967 – carnian, west carpathian mts., slovakia cymopolia heraki gušić, 1967 [? younger synonym of cymopolia mayaense johnson & kaska, 1965, after deloffre & radoičić, 1978] – middle maastrichtian, environs of jajce, bosnia and herzegovina hexaella heraki milanović, 1989 – lower permian, gorski kotar, croatia – problematic microfossil, probably an alga petrascula? heraki sokač & nikler, 1966 [cf. palaeodacycladus mediterraneus var. heraki (sokač & nikler, 1966) sokač, 2001] – lower liassic, velebit mt., croatia vanda kochansky-devidé cylindroporella kochanskyae radoičić, 1970 [typifi cation in radoičić, 1975] – lower turonian, milanovac mt., kosovo kochanskyella milanović, 1974 *kochanskyella tulipa milanović, 1974 – lower permian, environs of gospić, velebit mt., croatia salopekiella? kochanskae milanović, 1968, nom. nud. [cf. clavaporella kochanskae milanović ex vachard, 1980] – lower permian, environs of medak, velebit mt., croatia momčilo milanović milanovicella granier & berthou, 1994 *milanovicella momciliana granier & berthou, 1994 – portlandian algarve, portugal branko sokač aciculella sokaci bystrický, 1975 – norian, stratenská hornatina mts., slovakia fanesella sokaci barattolo& bigozzi, 1996 in barattolo et al., 1996 [younger synonym palaeodacycladus dolomiticus (cros & lemoine, 1966) sokač, 2001, after sokač, 2001] – lower jurassic, gran sasso mt., central apennines, italy leon nikler aciculella nikleri bystrický, 1975 – norian, stratenská hornatina mts., slovakia ivan gušić biokoviella gusici sokač, 2004 – upper barremian, biokovo mt., croatia dactylopora gusici bystrický, 1976 [younger synonym triploporella apenninica (baretti, 1922) barattolo, 1982, after barattolo, 1982]– paleocene, brezovica, west carpathian mts., slovakia acknowledgement finally, i would like to thank milan herak and branko sokač for their extensive information and interesting stories from the past and also ivan gušić, jasenka sremac and marc conrad for the photographs. references ampferer, o. (1915): zur erinnerung an r. j. schubert. – jahrb. geol. reichsanst., 65. anić, d. (1962): prilog poznavanju jure i krede istočnog dijela biokova (beiträge zur kenntnis der jura und kreideschichten des östlichen teiles des biokovo gebirges). – geol. vjesnik, 15/1, 161– 176. babić, lj., gušić, i. & zupanić, j. (1976): grebenski paleocen u baniji (središnja hrvatska) (paleocene reef limestone in banija, censtral croatia). – geol. vjesnik, 29, 11–47. bahun, s. & biondić, b. (1997): professor herak’s contribution to karst geology and hydrogeology. – geol, croat., 50/2, 161–162. barattolo, f. (1981): osservazioni su triploporella fraasi steinmann 1880 (alghe verdi, dasicladali). – atti accad. pontaniana, n.s., 30, 1–42. barattolo, f. (1982): osservazioni su triploporella apenninica baretti 1922 (alghe verdi, dasicladali) del paleocene dell’abruzzo aquilano. – geol. romana, xxi, 29–59. geologia croatica geologia croatica 61/2–3 62 barattolo, f., bigozzi, n. & potenza, a. (1996): dasycladaleans and depositional environments of the upper triassic–liassic carbonate platform of the gran sasso (central apennines, italy). – facies, 35, 163–208. baretti, a. (1919): contributo allo studio delle siphoneae verticillateae del calcare di villanova–mondovi. – atti della societa italiana di scienze naturali e del museo civico di storia naturale in milano, lviii, 216–236. baretti, a. (1922): alghe sifonee fossili nei calcari cretacici dell’apennino. – atti della societa italiana di scienze naturali e del museo civico di storia naturale in milano, lxi, 115–120. bassoullet, j.-p., bernier, p., conrad, m.a., deloffre, r. & jaffrezo, m. (1978): les algues dasycladales du jurassique et du crétacé. – géobios, mém. spec. 2, 330 p. benić, j., blašković, i. & tomić, v. (1997): professor herak’s contribution to regional geology and geotectonics. – geol. croat., 50/2, 157–160. bošković, d. & sokač, b. (1998): in memoriam: mr sc. leon nikler. – geol. croat., 51/2, 209–212. bucur, i. (1993): some new or poorly known calcareous algae (dasycladales, gymnocodiaceae) in the lower cretaceous deposits from the resita–moldova nona zone (southern carpathians, romania). – rev. esp. micropal., 25/1, 93–126. bystrický, j. (1967): die obertriadischen dasycladazeen der westkarpaten. – geol. sborník (geologica carpathica), 18/2, 285–309. bystrický, j. (1975): genus aciculella pia, 1930 (kalkalgen) in der trias der westkarpaten. – geol. zborník (geologica carpathica), 16/1, 1–20. bystrický, j. (1976): genus dactylopora lamarck, digitella morellet et morellet und broeckella morellet et morellet (dasycladaceae, algae) in kalken des paläozäns der westkarpaten. – geol. zborník (geologica carpathica), 27/2, 247–272. carozzi, a. (1954): l’organisme “c” j. favre (1927) est une vaginella portlandienne. – arch. sc., genève, 7/4, 107–111. conrad, m., peybernes, b. & masse, j.p. (1983): clypeina somalica n.sp. dasycladale nouvelle du crétacé inférieur de la plaque africaine (rép. de somalie, italié meridionale). – ann. soc. geol. du nord, lille, 93–95. conrad, m. a., praturlon, a. & radoičić, r. (1973): reinstatement of the genus salpingoporella pia (dasycladaceae) followed by s. steinhauseri n. sp. – c. r. soc. phys. hist. nat., 7/2–3, 103–111. conrad, m.a. & varol, b. (1990): cylindroporella taurica, n.sp., urges to review different patterns of calcifi cation in the mesozoic dasycladales (green algae). – arch. sci. genève, 43/1, 193–214. cros, p. & lemoine, m. (1966): dasycladacées nouvelles on peu connues du lias inférieur des dolomites et de quelques autres régions mediterranéennes (1re partie). – rev. micropal., 9/3, 156– 168. de castro, p. (1993): observations on campbelliella radoicic, 1959 and neoteutloporella bassoullet et al., 1978 (green algae, dasycladales). – in: barattolo, f., de castro, p. & parente, m. (eds.): studies on fossil benthic algae. boll. soc. paleont. italiana, spec. vol. 1, 121–184. deloffre, r. & radoičić, r. (1978): algues calcaires (dasycladales) du paléocène de slovénie. – bull. centre rech. explor., prod. elf, aquitaine, 2/1, 61–95. endo, r. (1951): stratigraphical and paleontological studies of the later paleozoic calcareous algae in japan i. several new species from the sakamotozawa section, hikoroichi-mura, kesen-gun, in the kitakami mountainous land. – trans. proc. palaeont. soc. japan, n.s., 4, 121–129. endo, r. (1958): stratigraphical and paleontological studies of the later paleozoic calcareous algae in japan, xiii. a restudy of the genus physoporella. – trans. proc. palaeont. soc. japan, n.s., 31, 265– 269. gorjanović-kramberger, d. (1900): geologijske i hidrografi jske crtice sa velebita [geological and hydrographical notes from mt. velebit – in croatian]. – glasnik hrvatskog naravoslovnog društva, zagreb, 11/1–6, 7–17. granier, b. & berthou, p.-y. (1994): description de milanovicella momciliana n. gen. n. sp., algue dasycladale du portlandien de l’algarve central (portugal), et validation de quelques taxons affi ns. – rev. micropal., 37/2, 113–121. granier, b. & deloffre, r. (1993): inventaire critique de algues dasycladales fossiles. ii° partie – les algues dasycladales du jurassique et du crétacé. – rev. paléobiol., 12/1, 19–65. granier, b. & deloffre, r. (1995): inventaire des algues dasycladales fossiles. iii° partie – les algues dasycladales du permien et du trias. rev. paléobiol., 14/1 (1994), 49–84. grgasović, t. (1997): upper triassic biostratigraphy and algae from žumberak (croatia). – geol. croat., 50/2, 201–214. grgasović, t. (2007): stop 3 – the sv. rok–mali alan road – ladinian limestones with diplopora annulata/kantia dolomitica. – in: grgasović, t. & vlahović, i. (eds.): 9th international symposium on fossil algae, field-trip guidebook and abstracts. hrvatski geološki institut – croatian geological survey, zagreb, 29– 32. grgasović, t. & vlahović, i. (eds.) (2007): 9th international symposium on fossil algae, field-trip guidebook and abstracts. – hrvatski geološki institut – croatian geological survey, zagreb, vi+262 p. grgasović, t., sokač, b. & halamić, j. (2002): scinderella scopuliformis nov.gen., nov.sp. (dasycladales, green algae) from the middle triassic of croatia. – geobios, 35, 303–312. gušić, i. (1966): two new dasyclad species of the subgenus pianella from the lower cretaceous of istria (dvije nove vrste dasikladaceja podroda pianella iz donje krede istre). – geol. vjesnik, 19 (1965), 35–46. gušić, i. (1969): the algal genera macroporella, salpingoporella and pianella (dasycladaceae). – taxon, 19/2, 257–261. gušić, i. (1973): o paleogenskim mikrofosilima u klastičnim naslagama kod karlovca (on the paleogene microfossils in the clastic deposits near karlovac (central croatia)). – geol. vjesnik, 25 (1971), 51–56. gušić, i. (1999): in memoriam: mr.sc. momčilo milanović (1925– 1998). – vijesti hrv. geol. društva, 36/2, 83–84 [in croatian]. gušić, i. & babić, lj. (1973): paleogenski vapnenci na medvednici (palaeogene limestones on mt. medvednica (north croatia)). – geol. vjesnik, 25 (1971), 287–292. gušić, i. & kranjec, v. (1997): professor milan herak – on the occasion of his 80th birthday. – geol. croat., 50/2, 139–141. güvenç, t. (1979): dasycladacées métaspondyles du paléozoique supérieur et du trias. – in: 2ème symposium international sur les algues fossiles (paris, 23–26 avril 1979). bull. centr. rech. expl.prod. elf-aquitaine, 3/2, 625–637. herak, m. (1943): zur kenntnis triadischer kalkschwamme (sycones). – neues jahrb. geol. palaeont., abh., b, 88, 107–135. geologia croatica 63 tonći grgasović: history of investigations on fossil algae in croatia herak, m. (1944): triaske vapnene spužve iz skupine “sycones” (triadischer kalkschwamme aus der gruppe “sycones”). – vjesnik hrv. drž. geol. zavoda, 2–3, 41–70. herak, m. (1950): ladiničke dasycladaceae jugoslavije i njihovo stratigrafsko značenje [ladinian dasycladacee and their stratigraphical importance – in croatian]. – rad jugosl. akad. znan. umjet., 280, 115–141. herak, m. (1953): paleobotanika za geologe i biologe [palaeobotany for geologists and botanists – in croatian]. – školska knjiga, zagreb, vii+160 p. herak, m. (1956): stratigrafska interpretacija trijaskih sedimenata s dasikladacejama u okolici gračaca u hrvatskoj (stratigraphische interpretation triadischer sedimente mit dasycladaceen in der umgebung von gračac in kroatien). – acta geol., 1 (prir. istraž. jugosl. akad. znan. umjet., 27), 149–154. herak, m. (1957): some problems in the dasyclad genus diplopora. – micropaleontology, 3/1, 49–52. herak, m. (1958): the dasyclad genus physoporella in the anisian of yugoslavia. – j. palaeont. soc. india, birbal sahni memorial number, 3, 59–63. herak, m. (1960): calcareous algae of the young palaeozoic, and mesozoic of yugoslavia and their application in the stratigraphy. – in: hessland, i. & erdtman, g. (eds.): part vi, proceedings of section 6, pre-quaternary micropaleontology. report of the twenty-first session, norden, international geological congress. det berlingske bogtrykkeri, copenhagen, 90–97. herak, m. (1963): paleobotanika [palaeobotany – in croatian]. – školska knjiga, zagreb, 180 p. herak, m. (1965a): comparative study of some triassic dasycladaceae in yugoslavia (komparativni studij nekih trijaskih dasikladaceja u jugoslaviji). – geol. vjesnik, 18/1 (1964), 3–34. herak, m. (1965b): naslage trijasa u okolici sv. roka u lici (triasablagerungen in der umgebung von sv. rok in der lika). – acta geol., 5 (prir. istraž. jugosl. akad. znan. umjet., 35), 85–95. herak, m. (1967): mesozoische kalkalgen der insel chios (griechenland). – neues jahrb. geol. pal., abh., 129/1, 97–104. herak, m. & kochansky, v. (1959): jurassic calcarous algae in some new localities in the dinaric mountains – croatia. – bull. sci. cons. acad. yougosl. (a), 4/4, 102–104. herak, m. & kochansky, v. (1960): gymnocodiacean calcareous algae in the permian of yugoslavia (gimnokodijacejske vapnenačke alge u permu jugoslavije). – geol. vjesnik, 13, 185–196. herak, m., kochansky, v. & gušić, i. (1977): the development of the dasyclad algae through the ages. – in: flügel, e. (ed.): fossil algae, recent results and developments. springer-verlag, berlin, 143–153. herak, m., sokač, b. & šćavničar, b. (1967): correlation of the triassic in sw lika, paklenica and gorski kotar (croatia). – geol. sbornik (geol. carpathica), 18/2, 189–202. hofmann, t. (1993): julius pia, an universally distinguished earth scientist. – in: höfling, moussavian. e. & piller, w.e. (eds.): facial development of algae-bearing carbonates sequences in the eastern alps. field trip guidebook, alpine algae ‘93, münchen und wiena, 21 p. homann, w. (1972): unterund tief-mittelpermische kalkalgen aus den rattendorfer schichten, dem trogkofel-kalk und dem treßdorfer kalk der karnischen alpen (österreich).– senckenbergiana lethaea, 53/3–4, 135–313. ivanović, a., sakač, k., marković, s., sokač, b., šušnjar, m., nikler, l. & šušnjara, a. (1973): osnovna geološka karta sfrj 1:100.000. list obrovac l33-140 [basic geological map 1:100.000, obrovac sheet – in croatian]. – institut za geološka istraživanja zagreb (1967), savezni geološki zavod, beograd. ivanović, a., sakač, k., sokač, b., vrsalović-carević, i. & zupanić, j. (1976): osnovna geološka karta sfrj 1:100.000, tumač za list obrovac l33-140 [basic geological map 1:100.000, geology of the obrovac sheet – in croatian]. – institut za geološka istraživanja zagreb (1967), savezni geološki zavod, beograd, 61 p. johnson, j.h. (1965): three lower cretaceous algae new to the americas. – journ. paleont., 39/4, 719–730. johnson, j. h. & kaska, h. v. (1965): fossil algae from guatemala. – colorado sch. mines prof. contrib. 1, 152 p. koch, g. & grgasović, t. (1997): professor herak’s contribution to triassic stratigraphy (doprinos prof. heraka stratigrafi ji trijasa). – geol. croat., 50/2, 151–155. kochansky-devidé, v. (1964): velebitella, eine neue jungpaläozoische diploporeengattung und ihre phylogenetischen verhältnisse (velebitella, novi gornjopaleozojski rod diploporea i njeni fi logenetski odnosi). – geol. vjesnik, 17 (1963), 135–142. kochansky-devidé, v. (1967): eine interessante neue physoporella-art (dasycladaceae) aus der trias von slowenien (interesantna nova vrsta roda physoporella (dasycladaceae) iz trijasa slovenije). – geol. vjesnik, 20 (1966), 171–174. kochansky-devidé, v. (1970): die kalkalgen des karbons vom velebit-gebirge (moskovien und kassimovien) (vapnenačke alge karbona velebita (moskovijen i kasimovijien)). – palaeont. jugosl., 10, 1–32. kochansky-devidé, v. (1979): connexia slovenica n. sp., eine leitende art der trogkofel-ablagerungen (perm) (connexia slovenica n. sp., značajna vrsta trogkofelskih naslaga (perm)). – palaeont. jugosl., 23, 1–10. kochansky, v. & herak, m. (1960): on the carboniferous and permian dasycladaceae of yugoslavia (o karbonskim i permskim dasikladacejama jugoslavije). – geol. vjesnik, 13 (1959), 65–94. kochansky-devidé, v. & milanović, m. (1962): donjop ermske fuzulinide i vapnenačke alge produčja tare u crnoj gori (unterpermische fusuliniden und kalkalgen des tara-gebiets in der mittleren crna gora (montenegro)). – geol. vjesnik, 15/1 (1961), 195–228. mamet, b. & roux, a. (1978): algues viséennes et namuriennes du tennessee (états-unis). – rev. micropal., 21/2, 68–97. mamet, b., roux, a. & nassichuk, w.w. (1987): algues carbonifères et permiennes de l’arctique canadien. – geol. surv. canada bull., 342, 143 p. masse, j.p. & luperto-sinni, e. (1989): cylindroporella lyrata, nouvelle espèce de dasycladale de l’aptien inférieur du domaine périméditeranéen nord occidental (cylindroporella lyrata, new species of dasycladal algae from the lower aptian of the ne perimediterranean domain – in french). – rev. micropaléont., 32/1, 30– 39. milanović, m. (1965): salopekiella, novi rod familije dasycladaceae iz permskih sedimenata velebita (salopekiella, a new genus of the dasycladaceae family from the permian sediments of the velebit range). – acta geol., 5 (prir. istraž., jugosl. akad. znan. umjet., 35), 373–382. milanović, m. (1966a): likanella – a new permian genus of the family dasycladaceae (likanella – novi permski rod familije dasycladaceae). – geol. vjesnik, 19 (1965), 9–14. geologia croatica geologia croatica 61/2–3 64 milanović, m. (1966b): goniolinopsis, a new permian genus of the family dasycladaceae (goniolinopsis, novi permski rod familije dasycladaceae). – geol. vjesnik, 19 (1965), 115–122. milanović, m. (1968): salopekiella? kochanskae n. sp. (dasycladaceae) from the permian of the velebit mountain (salopekiella? kochanskae n. sp. (dasycladaceae) iz perma velebita). – geol. vjesnik, 21 (1967), 157–160. milanović, m. (1974): kochanskyella (chlorophyta, dasycladaceae), a new permian genus of mount velebit, croatia (kochanskyella (chlorophyta, dasycladaceae) iz perma velebita). – geol. vjesnik, 27, 127–132. milanović, m. (1975): salopekiella? breziki n. sp. (calcareous algae, dasycladaceae) from the permian of mt. velebit (croatia) (salopekiella? breziki n. sp., (vapnenačke alge, dasycladaceae) iz perma velebita). – geol. vjesnik, 28, 81–86. milanović, m. (1989): hexaella heraki n. gen., n. sp., a new problematical (incertae sedis) microfossil from the lower permian of the gorski kotar region (croatia, yugoslavia) (novi problematični mikrofosil iz donjeg perma gorskog kotara). – geol. vjesnik, 42, 29–31. mu, xinan (1984): a new permian dasycladales (calcareous alga) from xizang, with a discussion on the genus goniolinopsis. – acta micropal. sinica, 1/1, 61–71. nikler, l. & sokač, b. (1965): cylindroporella anici n.sp. new dasycladaceae from the malm of velebit. – bull. sci. cons. acad. yougosl. (a), 10/4, 106–107. nikler, l. & sokač, b. (1967): fosilne dasycladaceae gornje jure velebita i sjeverozapadne velike kapele (fossil dasycladaceae from upper jurassic of the mount velebit and the nw part of the mount velika kapela). – rad jugosl. akad. znan. umjet., 345, 101– 134. nikler, l. & sokač, b. (1968): biostratigraphy of the jurassic of velebit (croatia) (biostratigrafi ja jure velebita). – geol. vjesnik, 21 (1967), 161–176. nikler, l.& sokač, b. (1970): clypeina calciformis n. sp., a new calcareous alga (dasycladaceae) from the upper jurassic of lastovo island (clypeina calciformis n. sp. vapnenačka alga iz malma otoka lastovo). – geol. vjesnik, 23 (1969), 139–144. nikler, l., sokač, b. & ivanović, a. (1964): die gasellschaften der mikrofossilien der jura und kreide des südöstlichen velebit. – bull. sci. cons. acad. yougosl., 9/3, 67–68. ott, e. (1972): neufunde anisischer dasycladaceen (kalkalgen) in österreich. – anz. math. –naturw. kl. österreich akad. wiss., 1972/9, 187–200. ott, e. & flaviani, a. (1983) eine neue kalkalgengattung (lagenoporella, dasycladales) aus dem oberjura von sardinien. neues jahrb. geol. paläontol. mh., 1983/1, 16–26. pia, j. (1912): neue studien über die triadischen siphoneae verticillatae. – beiträge zur paläontologie und geologie österreich-ungarns und des orients, wien und leipzig, 25, 25–81. pia, j. (1920): die siphoneae verticillatae vom karbon bis zur kreide. – abhandlungen der zoologisch-botanischen gesellschaft in wien, 11/2, 263 p. pia, j. (1925): die diploporen der trias von süddalmatien. – sitzungsberichte der akademie der wissenschaften in wien, mathematischnaturwissenschaftliche klasse, abte. i, 133/7–8 (1924), 329–346. pia, j. (1937): die wichtigsten kalkalgen des jungpaläozoikums und ihre geologische bedeutung. – deuxième congres pour l’avancement des études de stratigraphie carbonifère (1935), compte-rendu, heerlen, ii, 765–856. polšak, a., bajraktarević, z., gušić, i., sremac, j. & magaš, b. (1990): in memoriam: akademik vanda kochanskydevidé (10.4.1915.–26.2.1990). – geol. vjesnik, 43, 215–223 [in croatian]. praturlon, a. (1964): calcareous algae from jurassic-cretaceous limestone of central apennines (southern latium–abruzzi). – geol. romana, 3, 171–201. radoičić, r. (1959a): salpingoporella dinarica nov. spec. u donjokrednim sedimentima dinarida (salpingoporella dinarica nov. spec. dans les sédiments crétacés inférieur des dinarides). – geol. glasnik, 3, 33–42. radoičić, r. (1959b): paleontološke odlike sedimenata okoline bačinskog jezera (gradac–ploče) (les caracteristiques paléontologiques des sédiments des environs des bačinsko jezero, de dalmatie). – geol. glasnik, 3, 55–63. radoičić, r. (1959c): krupne tintinine campbelliella nov. gen. i daturellina nov. gen., preliminarna beleška (large tintinnina campbelliella nov. gen. and daturellina nov. gen., a preliminary note). – vesnik (a), 17, 79–86. radoičić, r. (1965): pianella turgida n. sp. from the cenomanian of the outer dinarides (pianella turgida n. sp. iz cenomana spoljašnjih dinarida). – geol. vjesnik, 18/1 (1964), 195–199. radoičić, r. (1967): salpingoporella melitae spec. nov. iz donjekrednih sedimenata spoljašnjih dinarida (salpingoporella melitae spec. nov. des sediments crétacés inférieurs des dinarides externes). – geol. anal. balkan. poluost., 33, 121–126. radoičić, r. (1968): likanella? danilovae spec. nov. i neke druge donjokredne dazikladacee iz spoljašnjih dinarida (likanella? danilovaae spec. nov. et quelques autres dasycladacées inférieures des dinarides externes). – vesnik (a), 26, 177–194. radoičić, r. (1969): a new lower cretaceous dasycladacea, clypeina pejovici and note on some clypeinae. – geol. romana, roma, 8, 71–84. radoičić, r. (1970): cylinroporella kochanskyae sp. nov. iz donjeg turona dinarida (cylindroporella kochanskyae sp. nov. du turonien inférieur des dinarides). – vesnik (a), 28, 357–362. radoičić, r. (1974): a new palaeocene actinoporella (dasycladaceae), a preliminary report. – bull. sci. cons. acad. yougosl. (a), 19/9–10. radoičić, r. (1975): likanella hammudai sp. n. iz gornje krede tripolitanije (libija) i starost slojeva sa dissocladella undulata raineri (likanella hammudai sp. nov. from the upper cretaceous of the tripoli area (libya) and the age of strata containing dissocladella undulata raineri). – geol. anali balk. poluost., 39, 148–152. radoičić, r. (2002): new dasycladalean alga from the upper cretaceous of the island pašman (croatia). – geol. anali balk. poluostr., 64, 83–87. rezak, r. (1959): permian algae from saudi arabia. – journ. paleont., 33/4, 531–539. roux, a. (1979): révision du genre epimastopora “pia, 1922” (dasycladaceae). – in: 2ème symposium international sur les algues fossiles (paris, 23–26 avril 1979). bull. centr. rech. explor.-prod. elfaquitaine, 3/2, 803–810. roux, a. (1991): révision des gymnocodiaceae (algues rouges, permien–crétacé). taxonomie, biostratigraphie, paléobiogéographie. 2e partie: inventaire taxonomique critique des especes de gymnocodiacées du permien et du trias. – rev. micropal., 34/2, 136–173. salopek, m. (1942): o gornjem paleozoiku velebita u okolici brušana i baških oštarija [on the upper palaeozoic of velebit mt. in the environ of brušane and baške oštarije – in croatian]. – rad hrv. akad. znan. umjet., 274, 218–272, zagreb. geologia croatica 65 tonći grgasović: history of investigations on fossil algae in croatia salopek, m. (1952): o gornjem permu velike paklenice u velebitu [on the upper permian of velika paklenica on velebit mt. – in croatian]. – rad jugosl. akad. znan. umjet., 289, 5–26, zagreb. schafhäutl, k.e. (1853): beiträge zur näheren kenntnis der bayern’schen voralpen. – neues jahrb. min., geol. paläont., 1853, 299–319. schafhäutl, k.e. (1863): süd-bayerns lethaea geognostica. geognostisch betrachtet in ihren petrefacten. – l. voss, leipzig, xvii + 487 p. steinmann, g. (1880): zur kenntnis fossiler kalkalgen (siphoneen). – neues jahrb. mine., geol. pal., ii, 130–140. schubert, r.j. (1907): vorläufi ge mitteilung über foraminifera und kalkalgen aus dem dalmatinischen karbon. – verhandl. kaiser.könig. geol. reichsanstalt, 8, 211–214. schubert, r.j. (1909): zur geologie der österreichischen velebit (nebst paläontologischen anhang). – jahrb. kaiser.-könig. geol. reichsanstalt, 58/2 (1908), 345–386. sokač, b. (1968): a new genus of calcareous algae from the middle triassic of velebit (novi rod vapnenačke alge iz srednjeg trijasa velebita). – geol. vjesnik, 21 (1967), 207–212. sokač, b. (1974): diplopora clavaeformis pia (chlorophyta, dasycladaceae) from the lower ladinian of mt. velebit (o vrsti diplopora clavaeformis pia (chlorophyta, dasycladaceae) iz donjeg ladinika velebita). – geol. vjesnik, 27, 133–141. sokač, b. (1985): triploporella bacilliformis n.sp. (dasycladaceae) from the lower cretaceous of the island of korčula (triploporella bacilliformis n.sp. (dasycladaceae) iz donje krede otoka korčule). – geol. vjesnik, 38, 67–72. sokač, b. (1986): clypeina radici n.sp. (calcareous algae; dasycladaceae) from the neocomian of the coastal part of the outer dinarides (clypeina radici n.sp. (dasycladaceae) iz neokoma priobalnog dijela vanjskih dinarida). – geol. vjesnik, 39, 43–54. sokač, b. (1987): on some controversial dasyclad genera and species and their stratigraphic position in the lower cretaceous deposits of the dinarides (o nekim spornim rodovima i vrstama dasikladaceja i njihovom stratigrafskom položaju u naslagama donje krede dinarida). – geol. vjesnik, 40, 9–38. sokač, b. (1988): fanesella anae n.sp., a new calcareous algae (dasycladaceae) from the lower lias of velebit mountain (croatia) (nova vapnenačka alga (dasycladaceae) iz donjeg lijasa velebita). – geol. vjesnik, 41, 9–14. sokač, b. (1989): macroporella aptiensis n.sp. (calcareous algae; dasycladales) from the peri-reefal lower aptian limestones in western croatia (macroporella aptiensis n.sp. (dasycladaceae) iz prigrebenskog razvoja donjeg apta zapadne hrvatske). – geol. vjesnik, 42, 1–6. sokač, b. (1990): cylindroporella bradarici n.sp. (calcareous algae; dasycladales) from the albian of the dinaric karst area (cylindroporella bradarici n.sp. (vapnenačka alga; dasycladales) iz alba dinarskog krša). – geol. vjesnik, 43, 1–6. sokač, b. (1992): two new species of calcareous algae (dasycladaceae) from the upper dogger of southern dalmatia (croatia) (dvije nove vrste vapnenačkih alga (dasycladaceae) iz gornjeg dogera južne dalmacije (hrvatska)). – geol. croat., 45, 15–24. sokač, b. (1993): salpingoporella robusta n. sp. (calcareous algae; dasycladales) from the upper barremian–lower aptian of mt. biokovo, croatia. – geol. croat., 46/2, 175–180. sokač, b. (1996): taxonomic review of some barremian and aptian calcareous algae (dasycladales) from the dinaric and adriatic karst regions of croatia. – geol. croat., 49/1, 1–79. sokač, b. (2000): salpingoporella donatae n.sp. (dasycladales) from upper cretaceous limestone of the environs of primošten (dalmatia, croatia). – geol. croat., 53/1, 199–207. sokač, b. (2001): lower and middle liassic calcareous algae (dasycladales) from mt. velebit (croatia) and mt. trnovski gozd (slovenia) with particular reference to the genus palaeodasycladus (pia, 1920) 1927 and its species. – gol. croat., 54/2, 133–257. sokač, b. (2004): on some peri-mediterranean lower cretaceous dasyclad species (calcareous algae; dasycladales) previously assigned to different genera. – geol. croat., 57/1, 15–53. sokač, b. (2005): linoporella vesiculifera n.sp., a new calcareous alga (dasycladales) from the upper barremian of mt. biokovo (karst dinarides, croatia). – geol. croat., 58/2, 119–131. sokač, b. & grgasović, t. (1995): dissocladella bystrickyi n.sp., a new calcareous alga (dasycladaceae) from upper triassic dolomites of mt. medvednica (northern croatia). – geol. croatica, 48/1, 1–7. sokač, b. & grgasović, t. (1998): asterocalculus heraki n.gen. n.sp., a new calcareous alga (gymnocodiaceae) from the upper triassic hauptdolomite of žumberak, north croatia. – facies, 38, 197– 206. sokač, b. & grgasović, t. (2004): megaporella nikleri n.sp., a new calcareous alga (dasycladales) from the upper barremian of mt. biokovo, croatia. – riv. ital. paleontol. stratigr., 110/3, 651– 658. sokač, b. & jelaska, v. (1991): salpingoporella polsaki n.sp. (calcareous algae; dasycladaceae) from the cenomanian deposits of the island of brač (salpingoporella polsaki n.sp. (vapnenačka alga; dasycladaceae) iz cenomana otoka brača). – geol. vjesnik, 44, 1–6. sokač, b. & nikler, l. (1966): two new species of the genus petrascula from the lower lias of the velebit mountain. – bull. sci. cons. acad., yougosl. (a), 11/1–2, 7–8. sokač, b. & nikler, l. (1969a): dinarella kochi n. gen., n. sp. (dasyc ladaceae) from the lias of the velebit mountain (dinarella kochi n. gen., n. sp. (dasycladaceae) iz lijasa velebita). – geol. vjesnik, 22 (1968), 303–308. sokač, b. & nikler, l. (1969b): o vrstama roda petrascula iz donjeg lijasa velebita (on the species of the genus petrascula from the lower liassic of velebit). – acta geol., 6 (prir. istraž., jugosl. akad. znan. umjet., 36), 103–112. sokač, b. & nikler, l. (1971): cymopolia longistila n. sp. a new calcareous alga (dasycladaceae) from the lower cretaceous of the dinaric mountains (cymopolia longistila n. sp. nova vapnenačka alga (dasycladaceae) iz donje krede dinarskog gorja). – geol. vjesnik, 24 (1970), 77–84. sokač, b. & nikler, l. (1973a): calcareous algae from the lower cretaceous of the environs of nikšić, crna gora (montenegro) (vapnenačke alge donjokrednih naslaga iz okoline nikšića u crnoj gori). – paleont. jugosl., 13, 1–57. sokač, b. & nikler, l. (1973b): linoporella kapelensis n. sp. (dasycladaceae) from the tithonian of mt. velika kapela (linoporella kapelensis n. sp. titonskih naslaga velike kapele). – geol. vjesnik, 26 (1972), 65–71. sokač, b. & nikler, l. (1975): two varieties of triploporella marsicana praturlon and triploporella issaoensis n.sp. (calcareous algae, dasycladaceae) from the lower cretaceous of the island of vis (dalmatia, southern croatia) (dva varijeteta vrste triploporella marsicana praturlon i triploporella issaoensis n.sp. (vapnenačke alge, dasycladaceae) iz donje krede otoka visa). – geol. vjesnik, 28, 119–131. geologia croatica geologia croatica 61/2–3 66 sokač, b. & velić, i. (1976): linoporella? svilajensis n.sp. (calcareous algae, dasycladaceae) from the upper jurassic? – lower cretaceous? limestone of mt. svilaja, southern croatia (dalmatia) (linoporella? svilajensis n.sp. (vapnenačke alge, dasycladaceae) iz gornjomalmskih ili donjokrednih vapnenaca planine svilaje). – geol. vjesnik, 29, 173–176. sokač, b. & velić, i. (1978a): redescription of the genus selliporella (calcareous algae, dasycladaceae) (ponovni opis roda selliporella (vapnenačke alge, dasycladaceae)). – geol. vjesnik, 30/1, 225–242. sokač, b. & velić, i. (1978b): biostratigrafska istraživanja donje krede vanjskih dinarida (i). neokom zapadne istre (biostratigraphic investigations of the lower cretaceous of the outer dinarids i. the neocomian of western istria). – geol. vjesnik, 30/1, 243–250. sokač, b. & velić, i. (1980): a new calcareous alga, salpingoporella biokoviensis n.sp. (dasycladaceae) from lower aptian deposits of mt. biokovo, dalmatia (south croatia). – geol. vjesnik, 31 (1979), 145–150. sokač, b. & velić, i. (1981a): humiella teutae n.gen. n.sp. (dasycladaceae) iz neokoma južne hercegovine (humiella teutae n.gen. n.sp. (dasycladaceae) from the neocomian of southern herzegovina). – geol. vjesnik, 33, 101–105. sokač, b. & velić, i. (1981b): korkyrella n.gen. (dasycladaceae) from the upper barremian and lower aptian of the island of korčula (korkyrella n.gen. (dasycladaceae) iz gornjeg barema i donjeg apta otoka korčule). – paleont. jugosl., 24, 1–12. sokač, b. & velić, i. (1981c): new calcareous algae (dasycladaceae) from the berriasian of the biokovo mountain (croatia) (nove vapnenačke alge (dasycladaceae) iz berijasa planine biokova (hrvatska)). – geol. vjesnik, 34, 39–46. sokač, b. & velić, i. (1982): gyroporella lukicae n.sp. (dasycladaceae) from the lower aptian of the surroundings of jajce (gyroporella lukicae n.sp. (dasycladaceae) iz donjeg apta okolice jajca). – geol. vjesnik, 35, 37–41. sokač, b. & velić, i. (1983): uragiella matzi n.sp. (dasycladaceae) from the upper cretaceous of primošten (uragiella matzi n.sp. (dasycladaceae) iz gornje krede primoštena). – geol. vjesnik, 36, 91–94. sokač, b., nikler, l., velić, i. & mamužić, p. (1974): osnovna geološka karta sfrj 1:100.000. list gospić l33-127 [basic geological map 1:100.000, gospić sheet – in croatian]. – institut za geološka istraživanja zagreb (1963–67), savezni geološki zavod, beograd. sokač, b., šušnjar, m., bukovac, j., bahun, s. (1976a): osnovna geološka karta sfrj 1:100.000. tumač za list udbina l33128 [basic geological map 1:100.000, geology of the udbina sheet – in croatian]. – institut za geološka istraživanja zagreb (1965), savezni geološki zavod, beograd, 62 p. sokač, b., šćavničar, b. & velić, i. (1976b): osnovna geološka karta sfrj 1:100.000. tumač za list gospić l33-127 [basic geological map 1:100.000, geology of the gospić sheet – in croatian]. – institut za geološka istraživanja zagreb (1967), savezni geološki zavod, beograd, 64 p. sokač, b., bahun, s., velić, i. & galović, i. (1976c): osnovna geološka karta sfrj 1:100.000. tumač za list otočac l33-115 [basic geological map 1:100.000, geology of the otočac sheet – in croatian]. – institut za geološka istraživanja zagreb (1970), savezni geološki zavod, beograd, 44 p. sokač, b., bajraktarević, z. & jurišić-polšak, z. (1997): academician milan herak’s main contribution to palaeontology. – geol. croat., 50/2, 143–146. sokač, b., nikler, l. & ivanović, a. (1964): fund von obertriadischen dasycladaceen im gebiet des velebit. – bull. sci. cons. acad. yougosl. (a), 9/6, 156–157. sremac, j. (1991): zona neoschwagerina craticulifera u srednjem velebitu (zone neoschwagerina craticulifera in the middle velebit mt. (croatia, yugoslavia)). – geologija, 34 (1991), 7–55. steinmann, g. (1899): ueber fossile dasycladacean vom cerro escamela, mexico. – bot. zeit. berlin, 57/8, 137–154. stolley, e. (1893): ueber silurische siphoneen. – neues jahrb. miner. geol. paläont., ii, 135–146. šikić, k. & šikić, l. (1978): paleocen u samoborskom gorju (the paleocene in the samobor highlands (north croatia)). – geol. vjesnik, 30/1, 265–280. šušnjar, m., sokač, b., bahun, s., m., bukovac, j., nikler, l. & ivanović, a. (1973): osnovna geološka karta sfrj 1:100.000. list udbina l33-128 [basic geological map 1:100.000, udbina sheet – in croatian]. – institut za geološka istraživanja zagreb (1962–1967), savezni geološki zavod, beograd. vachard, d. (1974): sur les dasycladacées métaspondyles “vestibulaires”, à propos d’un de leurs représentants viséens: eovelebitella occitanica n. gen. n. sp. – compte rendu acad. sci., paris, série d, 279, 1855–1858. vachard, d. (1980): téthys et gondwana au paléozoïque supérieur: les données afghanes; biostratigraphie, micropaléontologie, paléogéographie. – thèse doct. etat, documents et travaux igal, paris, 2, 2 vol.: 463 p. (texte), 35 pl. (atlas). velić, i. & sokač, b. (1974): o trodjelnoj podjeli malma u velikoj kapeli (on the tripartite subdivision of the malm in mt. velika kapela (croatia)). – geol. vjesnik, 27, 143–150. velić, i. & sokač, b. (1976): tintinnopsella kapelensis n.sp., a new aberrant tintinnid from the tithonian of mt. velika kapela, central croatia (tintinnopsella kapelensis n.sp. aberantna tintinina iz titona velike kapele). – geol. vjesnik, 29, 213–218. velić, i. & sokač, b. (1981): osnovna geološka karta sfrj 1:100.000. list ogulin l33-103 [basic geological map 1:100.000, ogulin sheet – in croatian]. – geološki zavod zagreb (1971–1976), savezni geološki zavod, beograd. velić, i., bahun, s., sokač, b. & galović, i. (1974): osnovna geološka karta sfrj 1:100.000, list otočac l33-115 [basic geological map 1:100.000, otočac sheet – in croatian]. – institut za geološka istraživanja zagreb (1970), savezni geološki zavod, beo grad. velić, i., tišljar, j. & sokač, b. (1979): stratigraphy and depositional environments of the lower cretaceous in the karst region of the outer dinarids (yugoslavia). – geobios, mem. spec., 3 (colloque l’ urgonien des pays mediterraneens, lyon, 1979), 245–252. velić, i., sokač, b. & šćavničar, b.(1982): osnovna geološka karta sfrj 1:100.000. tumač za list ogulin l33-103 [basic geological map 1:100.000, geology of the ogulin sheet – in croatian]. – geološki zavod zagreb (1980), savezni geološki zavod, beograd, 46 p. geologia croatica 67 tonći grgasović: history of investigations on fossil algae in croatia appendix references from 1907 to 2007, sorted after the year of publication: schubert, r.j. (1907): vorläufi ge mitteilung über foraminifera und kalkalgen aus dem dalmatinischen karbon.– verhandlungen der kaiserlich-königlichen geologischen reichsanstalt, 8, 211–214, wien. schubert, r.j. (1909): zur geologie der österreichischen velebit (nebst paläontologischen anhang). – jahrbuch der kaiserlichköniglichen geologischen reichsanstalt, 58/2 (1908), 345–386, 5 fi gs., 1 pl., wien. pia, j. (1920): die siphoneae verticillatae vom karbon bis zur kreide. – abhandlungen der zoologisch-botanischen gesellschaft in wien, 11/2, 263 p., wien. pia, j. (1925): die diploporen der trias von süddalmatien. – sitzungsberichte der akademie der wissenschaften in wien, mathematischnaturwissenschaftliche klasse, abteilung i, 133/7–8 (1924), 329– 346, 1 fi g., 1 tab., 1 pl., wien. herak, m. (1943): zur kenntnis triadischer kalkschwamme (sycones). – neues jahrb. geol. palaeontol., abh., b, 88, 107–135, 5 fi gs., 2 pls., stuttgart. herak, m. (1944): triaske vapnene spužve iz skupine “sycones” (triadischer kalkschwamme aus der gruppe “sycones”). – vjesnik hrvatskog državnog geoložkog zavoda, 2–3, 41–70, zagreb. herak, m. (1950): ladiničke dasycladaceae jugoslavije i njihovo stratigrafsko značenje [ladinian dasycladacee and their stratigraphical importance – in croatian]. – rad jugosl. akad. znan. umjet., 280, 115–141, 4 pls., zagreb. herak, m. (1953): paleobotanika za geologe i biologe [palaeobotany for geologists and botanists – in croatian]. – školska knjiga, zagreb, vii+160 p. herak, m. (1956): stratigrafska interpretacija trijaskih sedimenata s dasikladacejama u okolici gračaca u hrvatskoj (stratigraphische interpretation triadischer sedimente mit dasycladaceen in der umgebung von gračac in kroatien). – acta geol., 1 (prir. istraž. jugosl. akad. znan. umjet., 27), 149–154, 2 fi gs., zagreb. herak, m. & malez, m. (1956): teutloporella herculea (stopani) in the district of golubovec, n–w croatia. – bull. sci. cons. acad. yougosl. (a), 2/4, 106–107, zagreb. herak, m. (1957): some problems in the dasyclad genus diplopora. – micropaleontology, 3/1, 49–52, new york. herak, m. (1958): the dasyclad genus physoporella in the anisian of yugoslavia. – j. palaeont. soc. india, birbal sahni memorial number, 3, 59–63, 2 fi gs., 2 pls., lucknow. herak, m. & kochansky, v. (1959): jurassic calcarous algae in some new localities in the dinaric mountains – croatia. – bull. sci. cons. acad. yougosl. (a), 4/4, 102–104, 2 fi gs., zagreb. radoičić, r. (1959a): salpingoporella dinarica nov. spec. u donjokrednim sedimentima dinarida (salpingoporella dinarica nov. spec. dans les sédiments crétacés inférieur des dinarides). – geol. glasnik, 3, 33–42, 2 fi gs., 3 pls., titograd. radoičić, r. (1959b): paleontološke odlike sedimenata okoline bačinskog jezera (gradac–ploče) (les caracteristiques paléonto lo giques des sédiments des environs des bačinsko jezero, de dalmatie). – geol. glasnik, 3, 55–63, 1 fi g., 3 pls., titograd. radoičić, r. (1959c): krupne tintinine campbelliella nov. gen. i daturellina nov. gen., preliminarna beleška (large tintinnina campbelliella nov. gen. and daturellina nov. gen., a preliminary note). – vesnik (a), beograd, 17, 79–86. herak, m. (1960): calcareous algae of the young palaeozoic, and mesozoic of yugoslavia and their application in the stratigraphy. – in: hessland, i. & erdtman, g. (eds.): part vi, proceedings of section 6, pre-quaternary micropaleontology. report of the twenty-first session, norden, international geological congress. det berlingske bogtrykkeri, copenhagen, 90–97, 2 fi gs. herak, m. & kochansky, v. (1960): gymnocodiacean calcareous algae in the permian of yugoslavia (gimnokodijacejske vapnenačke alge u permu jugoslavije). – geol. vjesnik, 13, 185–196, 6 pls., zagreb. kochansky, v. & herak, m. (1960): on the carboniferous and permian dasycladaceae of yugoslavia (o karbonskim i permskim dasikladacejama jugoslavije). – geol. vjesnik, 13 (1959), 65–94, 9 pls., zagreb. radoičić, r. (1960): mikrofacije krede i starijeg tercijara spoljnih dinarida jugoslavije (microfaciès du crétacé et du paleogene des dinarides externes de yougoslavie). – paleontol. jugosl. dinarida, a, 4/1, 5–172, 1 fi g., 67 pls., titograd. anić, d. (1962): prilog poznavanju jure i krede istočnog dijela biokova (beiträge zur kenntnis der jura und kreideschichten des östlichen teiles des biokovo gebirges). – geol. vjesnik, 15/1, 161–176, zagreb. kochansky-devidé, v. & milanović, m. (1962): donjopermske fuzulinide i vapnenačke alge produčja tare u crnoj gori (unterpermische fusuliniden und kalkalgen des tara-gebiets in der mittleren crna gora (montenegro)). – geol. vjesnik, 15/1 (1961), 195–228, 8 pls., zagreb.* herak, m. (1963): paleobotanika [palaeobotany – in croatian]. – školska knjiga, zagreb, 180 p., 148 fi gs. herak, m. & kochansky, v. (1963): bükkhegységi újpaleozóos mészalgak (jungpaläozoische kalkalgen aus dem bükk-gebirge (nordungarn)). – geol. hung., ser. paleontol., 28, 45–77, 3 fi gs., 4 pls., 1 tab., budapest. * kochansky-devidé, v. (1964a): velebitella, eine neue jungpaläozoische diploporeengattung und ihre phylogenetischen verhältnisse (velebitella, novi gornjopaleozojski rod diploporea i njeni fi logenetski odnosi). – geol. vjesnik, 17 (1963), 135–142, 1 fi g., 4 pls., zagreb. kochansky-devidé, v. (1964b): die mikrofossilien des jugoslawischen perms. – palaeontol. zeitschrift, 38/3–4, 180–188, 2 pls., stuttgart. kochansky-devidé, v. (1964c): die fusuliniden und kalkalgen des jugoslavischen karbons. – c.r. v congr. strat. géol. carbon. (1963), 2, 513–518, 1 fi g., 3 pls., paris. nikler, l., sokač, b. & ivanović, a. (1964): die gasellschaften der mikrofossilien der jura und kreide des südöstlichen velebit. – bull. sci. cons. acad. yougosl. (a), 9/3, 67–68, zagreb. sokač, b., nikler, l. & ivanović, a. (1964): fund von obertriadischen dasycladaceen im gebiet des velebit. – bull. sci. cons. acad. yougosl. (a), 9/6, 156–157, 2 fi gs., zagreb. herak, m. (1965a): comparative study of some triassic dasycladaceae in yugoslavia (komparativni studij nekih trijaskih dasikladaceja u jugoslaviji). – geol. vjesnik, 18/1 (1964), 3–34, 1 fi g., 15 pls., zagreb. herak, m. (1965b): naslage trijasa u okolici sv. roka u lici (triasablagerungen in der umgebung von sv. rok in der lika). – acta geol., 5 (prir. istraž. jugosl. akad. znan. umjet., 35), 85–95, 1 fi g., 1 map, zagreb. geologia croatica geologia croatica 61/2–3 68 herak, m. (1965c): die kalkalgen in der stratigraphie der dinariden (jungpaläozoikum und mesozoikum). – mitt. geol. ges. wien, 58, 209–217, wien. kochansky-devidé, v. & ramovš, a. (1965): razvoj mlajšega paleozoika v okolici ortneka na dolenjskem. – razprave slov. akad. znan. umet. (razr. prir. med. vede), 8, 319–416, 18 pls., ljubljana.* milanović, m. (1965a): salopekiella, novi rod familije dasycladaceae iz permskih sedimenata velebita (salopekiella, a new genus of the dasycladaceae family from the permian sediments of the velebit range). – acta geol., 5 (prir. istraž., jugosl. akad. znan. umjet., 35), 373–382, 4 fi gs., 3 pls. zagreb. milanović, m. (1965b): zwei neue gattungen der familie dasycladaceae aus dem perm velebitgebirges. – bull. sci. cons. acad. yougosl. (a), 10/6, 179–180, 2 fi gs., zagreb. nikler, l. & sokač, b. (1965a): die notwendigkeit der einführung von zwei subgenuse bei der gattung macroporella. – bull. sci. cons. acad. yougosl. (a), 10/4, 105, zagreb. nikler, l. & sokač, b. (1965b): cylindroporella anici n.sp. new dasycladaceae from the malm of velebit. – bull. sci. cons. acad. yougosl. (a), 10/4, 106–107, 4 fi gs., zagreb. radoičić, r. (1965): pianella turgida n. sp. from the cenomanian of the outer dinarides (pianella turgida n. sp. iz cenomana spoljašnjih dinarida). – geol. vjesnik, 18/1 (1964), 195–199, 1 fi g., 5 pls., zagreb. gušić, i. (1966): two new dasyclad species of the subgenus pianella from the lower cretaceous of istria (dvije nove vrste dasikladaceja podroda pianella iz donje krede istre). – geol. vjesnik, 19 (1965), 35–46, 6 pls., zagreb. kochansky-devidé, v. & ramovš, a. (1966): zgornjekarbonski mikrofosili in stratigrafski razvoj v zahodnih karavankah (oberkarbonische mikrofossilien und stratigraphische entwicklung in den westkarawanken). – razprave slov. akad. znan. umet. (razr. prir. med. vede), 9/7, 299–333, 11 pl., ljubljana.* milanović, m. (1966a): likanella – a new permian genus of the family dasycladaceae (likanella – novi permski rod familije dasycladaceae). – geol. vjesnik, 19 (1965), 9–14, 4 pls., zagreb. milanović, m. (1966b): goniolinopsis, a new permian genus of the family dasycladaceae (goniolinopsis, novi permski rod familije dasycladaceae). – geol. vjesnik, 19 (1965), 115–122, 3 fi gs., 3 pls., zagreb. radoičić, r. (1966): microfaciès du jurassique des dinarides externes de la yougoslavie. – geologija, 9, 5–376, 1 fi g., 11 tab., 165 pls., ljubljana. sokač, b. & nikler, l. (1966): two new species of the genus petrascula from the lower lias of the velebit mountain. – bull. sci. cons. acad., yougosl. (a), 11/1–2, 7–8, 1 fi g., zagreb. gušić, i. (1967): new dasycladaceae from the maastrichtian of bešpelj near jajce (western bosnia) (nove dasikladaceje iz mastrihta bešpelja kod jajca). – geol. vjesnik, 20 (1966), 117–125, 6 pls., zagreb.* herak, m. (1967a): mesozoische kalkalgen der insel chios (griechenland). – neues jahrb. geol. palaeontol., abh., 129/1, 97–104, 1 tabl., 5 pls., stuttgart.* herak, m. (1967b): anisische dasycladaceen vom gosaukamm (dachsteingebiet, österreich). – mitt. geol. ges. wien, 59/2 (1966), 213– 217, 3 pls., wien.* herak, m., sokač, b. & šćavničar, b. (1967): correlation of the triassic in sw lika, paklenica and gorski kotar (croatia). – geol. sbornik (geol. carpathica), 18/2, 189–202, 5 fi gs., 1 tab., bratislava. herak, m. & škalec, d. (1967): kalkalgen im perm des samoborer gebirges (vapnenačke alge u permu samoborskog gorja). – geol. vjesnik, 20 (1966), 37–40, 1 fi g., 1 pl., zagreb. kochansky-devidé, v. (1967): eine interessante neue physoporella-art (dasycladaceae) aus der trias von slowenien (interesantna nova vrsta roda physoporella (dasycladaceae) iz trijasa slovenije). – geol. vjesnik, 20 (1966), 171–174, 1 pl., zagreb.* nikler, l. & sokač, b. (1967): fosilne dasycladaceae gornje jure velebita i sjeverozapadne velike kapele (fossil dasycladaceae from upper jurassic of the mount velebit and the nw part of the mount velika kapela). – rad jugosl. akad. znan. umjet., 345, 101– 134, 3 fi gs., 8 pls., zagreb. praturlon, a. & radoičić, r. (1967): note on the dasyclad genus salpingoporella pia. – geol. romana, 6, 137–144, 5 fi gs., roma. radoičić, r. (1967): salpingoporella melitae spec. nov. iz donjekrednih sedimenata spoljašnjih dinarida (salpingoporella melitae spec. nov. des sediments crétacés inférieurs des dinarides externes). – geol. anali balk. poluostr., 33, 121–126, 4 pls., beograd. sokač, b. & nikler, l. (1967): teutloporella elongatula (praturlon, 1966), sokač & nikler, calcareous alga from the middle liassic of velebit (teutloporella elongatula (praturlon, 1966), sokač & nikler, vapnenačka alga iz srednjeg lijasa velebita). – geol. vjesnik, 20 (1966), 111–116, 6 pls., zagreb. milanović, m. (1968): salopekiella? kochanskae n. sp. (dasycladaceae) from the permian of the velebit mountain (salopekiella? kochanskae n. sp. (dasycladaceae) iz perma velebita). – geol. vjesnik, 21 (1967), 157–160, 4 pls., zagreb. nikler, l. & sokač, b. (1968): biostratigraphy of the jurassic of velebit (croatia) (biostratigrafi ja jure velebita). – geol. vjesnik, 21 (1967), 161–176, 1 fi g., 15 pls., zagreb. radoičić, r. (1968): likanella? danilovae spec. nov. i neke druge donjokredne dazikladacee iz spoljašnjih dinarida (likanella? danilovaae spec. nov. et quelques autres dasycladacées inférieures des dinarides externes). – vesnik (a), 26, 177–194, 2 fi gs., 16 pls., beograd. sokač, b. (1968): a new genus of calcareous algae from the middle triassic of velebit (novi rod vapnenačke alge iz srednjeg trijasa velebita). – geol. vjesnik, 21 (1967), 207–212, 4 pls., zagreb. gušić, i. (1969): the algal genera macroporella, salpingoporella and pianella (dasycladaceae). – taxon, 19/2, 257–261, utrecht. kochansky-devidé, v. & slišković, t. (1969): gornjopermski mikrofosili han orahovice i šuljaca u bosni s osobitim obzirom na algu permocalculus fragilis (ober permische mikrofossilien von han orahovica und šuljci in bosnien mit besonder berücksichtigung der alge permocalculus fragilis). – geol. vjesnik, 22 (1968), 105–110, 2 pls., zagreb.* radoičić, r. (1969a): aberantna grana fosilnih tintinina (podred tintinnina) (la branche aberrante des tintinnines fossiles (sous-ordre tintinnina)). – paleont. jugosl., 9, 5–71, 31 fi g., 8 pls., zagreb. radoičić, r. (1969b): a new lower cretaceous dasycladacea, clypeina pejovici and note on some clypeinae. – geol. romana, 8,71– 84, 15 fi gs., roma. radoičić, r. (1969c): koptokampilodoni u nekim jurskim i krednim sedimentima jugoslavije (coptocampylodons de certain sédiments jurassiques et crétacée de la yougoslavie). – vesnik (a), 27, 191– 200, 7 pls., beograd. sokač, b. & nikler, l. (1969a): dinarella kochi n. gen., n. sp. (dasycladaceae) from the lias of the velebit mountain (dinarella kochi n. gen., n. sp. (dasycladaceae) iz lijasa velebita). – geol. vjesnik, 22 (1968), 303–308, 1 fi g., 2 pls., zagreb. geologia croatica 69 tonći grgasović: history of investigations on fossil algae in croatia sokač, b. & nikler, l. (1969b): o vrstama roda petrascula iz donjeg lijasa velebita (on the species of the genus petrascula from the lower liassic of velebit). – acta geol., 6 (prir. istraž., jugosl. akad. znan. umjet., 36), 103–112, 3 fi gs., 7 pls., zagreb. gušić, i., nikler, l. & sokač, b. (1970): the jurassic in the dinaric mountains of croatia and the problems of its subdivisions. – ann. inst. geol. publ. hung., 54/2 (coll. jurassique méditerr., budapest, 1969), 165–183, 4 fi gs., 1 pl., budapest. kochansky-devidé, v. (1970a): permski mikrofosili zahodnih karavank (permische mikrofossilien der westkarawanken). – geologija, 13, 175–256, 26 pls., ljubljana.* kochansky-devidé, v. (1970b): die kalkalgen des karbons vom velebit-gebirge (moskovien und kassimovien) (vapnenačke alge karbona velebita (moskovijen i kasimovijien)). – palaeont. jugosl., 10, 1–32, 15 pls., zagreb. nikler, l. & sokač, b. (1970): clypeina calciformis n. sp., a new calcareous alga (dasycladaceae) from the upper jurassic of lastovo island (clypeina calciformis n. sp. vapnenačka alga iz malma otoka lastovo). – geol. vjesnik, 23 (1969), 139–144, 3 pls., 1 tab., zagreb. kochansky-devidé, v. & gušić, i. (1971): evolutions-tendenzen der dasycladaceen mit besonderer berücksichtigung neuer funde in jugoslawien. – palaeontol. zeitschrift, 45/1–2, 82–91, stuttgart. radoičić, r. (1970a): prilog poznavanju geologije pelješca i paleogeografi je ovog dijela spoljašnjih dinarida (a study of the geology of pelješac peninsula and the paleogeography of this part of the outher dinarides). – vesnik (a), 28, 175–184, 3 pls., beograd. radoičić, r. (1970b): alge u juri i kredi južne hercegovine (algae in the jurassic and cretaceous of south hercegovina). – geol. glasnik, 14, 99–107, 14 pls., sarajevo. radoičić, r. (1970c): deux pseudoclypéines jurassique supérieur des dinarides yougoslaves. – rev. micropaléont., 13/2, 115–121, 1 fi g., 3 pls., paris. sokač, b. & nikler, l. (1971): cymopolia longistila n. sp. a new calcareous alga (dasycladaceae) from the lower cretaceous of the dinaric mountains (cymopolia longistila n. sp. nova vapnenačka alga (dasycladaceae) iz donje krede dinarskog gorja). – geol. vjesnik, 24 (1970), 77–84, 2 fi gs., 2 pls., zagreb. homann, w. (1972): unterund tief-mittelpermische kalkalgen aus den rattendorfer schichten, dem trogkofel-kalk und dem treßdorfer kalk der karnischen alpen (österreich). – senckenbergiana lethaea, frankfurt am main, 53/3–4, 135–313, 10 fi gs., 60 tabs., 10 pls. gušić, i. (1973a): stratigrafsko značenje mezozojskih dazikladaceja s obzirom na nova taksa u jugoslaviji (stratigraphic signifi cance of mesozoic dasycladaceans with regard to new taxa in yugoslavia). – geologija, 16, 371–372, ljubljana. gušić, i. (1973b): o paleogenskim mikrofosilima u klastičnim naslagama kod karlovca (on the paleogene microfossils in the clastic deposits near karlovac (central croatia)). – geol. vjesnik, 25 (1971), 51–56, 2 pls., zagreb. gušić, i. & babić, lj. (1973): paleogenski vapnenci na medvednici (palaeogene limestones on mt. medvednica (north croatia)). – geol. vjesnik, 25 (1971), 287–292, zagreb. kochansky-devidé, v., buser, s., cajhen, j. & ramovš, a. (1973): podroben profi l skrozi trogkofelske plasti v potoku košutnik v karavankah (detaillertes profi l durch die trogkofel-schichten am košutnik-bach in der karawanken). – razprave slov. akad. znan. umet. (razr. prir. med. vede), 16/4, 171–187, 5 pls., ljubljana.* sokač, b. (1973): geologija velebita (geology of velebit mt.). – unpublished phd thesis, faculty of science, zagreb university, iv+151 p., 38 fi gs., 7 suppls. sokač, b. & nikler, l. (1973a): calcareous algae from the lower cretaceous of the environs of nikšić, crna gora (montenegro) (vapnenačke alge donjokrednih naslaga iz okoline nikšića u crnoj gori). – paleont. jugosl., 13, 1–57, 16 pls., 1 tab., zagreb. * sokač, b. & nikler, l. (1973b): linoporella kapelensis n. sp. (dasycladaceae) from the tithonian of mt. velika kapela (linoporella kapelensis n. sp. titonskih naslaga velike kapele). – geol. vjesnik, 26 (1972), 65–71, 3 pls., zagreb. milanović, m. (1974): kochanskyella (chlorophyta, dasycladaceae), a new permian genus of mount velebit, croatia (kochanskyella (chlorophyta, dasycladaceae) iz perma velebita). – geol. vjesnik, 27, 127–132, 2 fi gs., 5 pls., zagreb. radoičić, r. (1974): a new palaeocene actinoporella (dasycladaceae), a preliminary report. – bull. sci. cons. acad. yougosl. (a), 19/9–10, 1 fi g., zagreb. sokač, b. (1974): diplopora clavaeformis pia (chlorophyta, dasycladaceae) from the lower ladinian of mt. velebit (o vrsti diplopora clavaeformis pia (chlorophyta, dasycladaceae) iz donjeg ladinika velebita). – geol. vjesnik, 27, 133–141, 5 pls., zagreb. velić, i. & sokač, b. (1974): o trodjelnoj podjeli malma u velikoj kapeli (on the tripartite subdivision of the malm in mt. velika kapela (croatia)). – geol. vjesnik, 27, 143–150, 1 tab., zagreb. milanović, m. (1975): salopekiella? breziki n. sp. (calcareous algae, dasycladaceae) from the permian of mt. velebit (croatia) (salopekiella? breziki n. sp., (vapnenačke alge, dasycladaceae) iz perma velebita). – geol. vjesnik, 28, 81–86, 1 fi g., 3 pls., zagreb. radoičić, r. (1975): linoporella buseri sp. nov. from the liassic of the julian alps (a preliminary report). bull. sci. cons. acad. yougosl. (a), 20/9–10, 277–278, zagreb. sokač, b. & nikler, l. (1975): two varieties of triploporella marsicana praturlon and triploporella issaoensis n.sp. (calcareous algae, dasycladaceae) from the lower cretaceous of the island of vis (dalmatia, southern croatia) (dva varijeteta vrste triploporella marsicana praturlon i triploporella issaoensis n.sp. (vapnenačke alge, dasycladaceae) iz donje krede otoka visa). – geol. vjesnik, 28, 119–131, 6 pls., zagreb. babić, lj., gušić, i. & zupanić, j. (1976): grebenski paleocen u baniji (središnja hrvatska) (paleocene reef limestone in banija, censtral croatia). – geol. vjesnik, 29, 11–47, 3 fi gs., 3 tabs., 10 pls., zagreb. sokač, b. & velić, i. (1976): linoporella? svilajensis n.sp. (calcareous algae, dasycladaceae) from the upper jurassic? – lower cretaceous? limestone of mt. svilaja, southern croatia (dalmatia) (linoporella? svilajensis n.sp. (vapnenačke alge, dasycladaceae) iz gornjomalmskih ili donjokrednih vapnenaca planine svilaje). – geol. vjesnik, 29, 173–176, 2 pls., zagreb. velić, i. & sokač, b. (1976): tintinnopsella kapelensis n.sp., a new aberrant tintinnid from the tithonian of mt. velika kapela, central croatia (tintinnopsella kapelensis n.sp. aberantna tintinina iz titona velike kapele). – geol. vjesnik, 29, 213–218, 1 pl., zagreb. flügel, e. (1977): environmental models for upper paleozoic benthic calcareous algal communities. – in: flügel, e. (ed.): fossil algae. recent results and developments. springer-verlag, p. 314– 343, 4 pls., berlin. herak, m., kochansky, v. & gušić, i. (1977): the development of the dasyclad algae through the ages. – in: flügel, e. (ed.): fossil algae, recent results and developments. springer-verlag, 143–153, 2 fi gs, berlin. geologia croatica geologia croatica 61/2–3 70 sokač, b. & velić, i. (1978a): redescription of the genus selliporella (calcareous algae, dasycladaceae) (ponovni opis roda selliporella (vapnenačke alge, dasycladaceae)). – geol. vjesnik, 30/1, 225– 242, 9 pls., zagreb. sokač, b. & velić, i. (1978b): biostratigrafska istraživanja donje krede vanjskih dinarida (i). neokom zapadne istre (biostratigraphic investigations of the lower cretaceous of the outer dinarids i. the neocomian of western istria). – geol. vjesnik, 30/1, 243–250, 8 pls., zagreb. šikić, k. & šikić, l. (1978): paleocen u samoborskom gorju (the paleocene in the samobor highlands (north croatia)). – geol. vjesnik, 30/1, 265–280, 1 fi g., 15 pls., zagreb. velić, i. & sokač, b. (1978): biostratigrafska analiza jure i donje krede šire okolice ogulina (središnja hrvatska) (biostratigraphic analysis of the jurassic and lower cretaceous in the wider region of ogulin, central croatia). – geol. vjesnik, 30/1, 309–337, 1 fi g., 13 pls., zagreb. kochansky-devidé, v. (1979): connexia slovenica n. sp., eine leitende art der trogkofel-ablagerungen (perm) (connexia slovenica n. sp., značajna vrsta trogkofelskih naslaga (perm)). – palaeont. jugosl., 23, 1–10, 2 pls., zagreb.* sokač, b. & velić, i. (1979a): triassic, jurassic and lower cretaceous of the karst part of the dinarids in the western croatia. – guidebook 16th european micropal. colloquium, 79–100, 3 fi gs., ljubljana–zagreb. sokač, b. & velić, i. (1979b): lower cretaceous in western istria. excursion j (limska draga). – guidebook 16th european micropal. colloquium, 209–216, 2 fi gs., ljubljana–zagreb. velić, i. & sokač, b. (1979): younger lower cretaceous and lower cenomanian of central croatia. excursion c (karlovac–ogulin). – guidebook 16th european micropal. colloquim, 147–152, 2 fi gs., ljubljana–zagreb. velić, i., tišljar, j. & sokač, b. (1979): stratigraphy and depositional environments of the lower cretaceous in the karst region of the outer dinarids (yugoslavia). – geobios, mem. spec. 3 (colloque l’ urgonien des pays mediterraneens, lyon, 1979), 245–252, 3 fi gs., lyon. babić, lj. & zupanić, j. (1980): uloga antagonističkih procesa izgradnje i razgradnje grebena u povijesti poroziteta – primjer paleocenskog grebena u baniji (the role of antagonistic processes of reef construction and destruction in the porosity history – example of paleocene reef in the banija region (“inner” dinaric belt)). – geol. vjesnik, 32 (1979), 33–51, 9 fi gs., zagreb. sokač, b. & velić, i. (1980): a new calcareous alga, salpingoporella biokoviensis n.sp. (dasycladaceae) from lower aptian deposits of mt. biokovo, dalmatia (south croatia). – geol. vjesnik, 31 (1979), 145–150, 3 pls., zagreb. babić, lj. & zupanić, j. (1981): various pore types in a paleocene reef, banija, yugoslavia. – in: toomey, d.f. (ed.): european fossil reef models. soc. econom. paleont. mineral. spec. publ., 30, 473–482, 15 fi gs., tulsa. bignot, g. (1981): illustration and paleoecological signifi cance of cretaceous and eocene girvanella limestones from istria (yugoslavia, italy). – in: monty, c. (ed.): phanerozoic stromatolites. springerverlag, 134–139, 2 fi gs., berlin. sokač, b. & velić, i. (1981a): humiella teutae n.gen. n.sp. (dasycladaceae) iz neokoma južne hercegovine (humiella teutae n.gen. n.sp. (dasycladaceae) from the neocomian of southern herzegovina). – geol. vjesnik, 33, 101–105, 2 pls., zagreb. sokač, b. & velić, i. (1981b): korkyrella n.gen. (dasycladaceae) from the upper barremian and lower aptian of the island of korčula (korkyrella n.gen. (dasycladaceae) iz gornjeg barema i donjeg apta otoka korčule). – paleont. jugosl., 24, 1–12, 1 fi g., 3 pls., zagreb. sokač, b. & velić, i. (1981c): new calcareous algae (dasycladaceae) from the berriasian of the biokovo mountain (croatia) (nove vapnenačke alge (dasycladaceae) iz berijasa planine biokova (hrvatska)). – geol. vjesnik, 34, 39–46, 3 pls., zagreb. milanović, m. (1982a): carboniferous microfossil associations from gorski kotar, hrvatsko zagorje and banija (karbonske mikrofosilne asocijacije gorskog kotara, hrvatskog zagorja i banije). – palaeont. jugosl., 28, 1–34, 2 fi gs., 10 pls., zagreb. milanović, m. (1982b): kabonski mikrofosili gorskog kotara, hrvatskog zagorja i banije (carboniferous microfossils from gorski kotar, hrvatsko zagorje and banija). – x kongres geologa jugoslavije, 1, 161–168, budva. sokač, b. & velić, i. (1982): gyroporella lukicae n.sp. (dasycladaceae) from the lower aptian of the surroundings of jajce (gyroporella lukicae n.sp. (dasycladaceae) iz donjeg apta okolice jajca). – geol. vjesnik, 35, 37–41, 2 pls., zagreb.* sokač, b. & velić, i. (1983): uragiella matzi n.sp. (dasycladaceae) from the upper cretaceous of primošten (uragiella matzi n.sp. (dasycladaceae) iz gornje krede primoštena). – geol. vjesnik, 36, 91–94, 1 pl., zagreb. velić, i. & sokač, b. (1983): stratigraphy of the lower cretaceous index fossils in the karst dinarides (yugoslavia). – zitteliana, 10 (2. symp. kreide), 485–491, 1 fi g., münchen. flügel, e., kochansky-devidé, v. & ramovš, a. (1984): a middle permian calcisponge/algal/cement reef: straža near bled, slovenia. – facies, 10, 179–256, 19 pls., erlangen.* gušić, i., wohlfeil, h. & wohlfeil, k. (1984): zur atersstellung und fazies des kalkes von kalecik (devon) und der akdarserie (trias) im nordöstlichen teil von karaburun (westl. izmir, türkei). – neues jahrb. geol. palaeontol., abh., 167/3, 375–404, stuttgart.* sokač, b. (1985): triploporella bacilliformis n.sp. (dasycladaceae) from the lower cretaceous of the island of korčula (triploporella bacilliformis n.sp. (dasycladaceae) iz donje krede otoka korčule). – geol. vjesnik, 38, 67–72, 2 pls., zagreb. milanović, m. (1986): permski mikrofosili gorskog kotara. – xi kongres geologa jugoslavije, 2, 91–98, 4 pls., tara. sokač, b. (1986): clypeina radici n.sp. (calcareous algae; dasycladaceae) from the neocomian of the coastal part of the outer dinarides (clypeina radici n.sp. (dasycladaceae) iz neokoma priobalnog dijela vanjskih dinarida). – geol. vjesnik, 39, 43–54, 3 pls., zagreb. radoičić, r. (1987): prilog stratigrafi ji hvara, povodom istovremenog pojavljivanja vrsta algi salpingoporella melitae i dinarica (a contribution to the study of stratigraphy of hvar, followed by simultaneous occurrences of the species salpingoporella melitae and s. dinarica). – glasnik srp. akad. nauka umet., od. prir. mat. nauka, 51, 73–79, 2 pls., beograd. sokač, b. (1987): on some controversial dasyclad genera and species and their stratigraphic position in the lower cretaceous deposits of the dinarides (o nekim spornim rodovima i vrstama dasikladaceja i njihovom stratigrafskom položaju u naslagama donje krede dinarida). – geol. vjesnik, 40, 9–38, 1 fi g., 12 pls., zagreb. sokač, b. (1988): fanesella anae n.sp., a new calcareous algae (dasycladaceae) from the lower lias of velebit mountain (croatia) (nova vapnenačka alga (dasycladaceae) iz donjeg lijasa velebita). – geol. vjesnik, 41, 9–14, 4 pls., zagreb. geologia croatica 71 tonći grgasović: history of investigations on fossil algae in croatia čosović, v. & glovacki-jernej, ž. (1989): some reef buildups with algae in the northwestern part of yugoslavia. – in: braga, j.c. & martin, j.m. (eds.): algae in reefs, abstracts, 13, granada. milanović, m. (1989): hexaella heraki n. gen., n. sp., a new problematical (incertae sedis) microfossil from the lower permian of the gorski kotar region (croatia, yugoslavia) (novi problematični mikrofosil iz donjeg perma gorskog kotara). – geol. vjesnik, 42, 29–31, 1 pl., zagreb. sokač, b. (1989): macroporella aptiensis n.sp. (calcareous algae; dasycladales) from the peri-reefal lower aptian limestones in western croatia (macroporella aptiensis n.sp. (dasycladaceae) iz prigrebenskog razvoja donjeg apta zapadne hrvatske). – geol. vjesnik, 42, 1–6, 2 pls., zagreb. dragastan, o. (1990): new “porostromata” algae of the mesozoic (iii). – rev. espan. micropal., 22/1, 5–32,¸11 pl., madrid. sokač, b. (1990): cylindroporella bradarici n.sp. (calcareous algae; dasycladales) from the albian of the dinaric karst area (cylindroporella bradarici n.sp. (vapnenačka alga; dasycladales) iz alba dinarskog krša). – geol. vjesnik, 43, 1–6, 2 pls., zagreb. arnaud-vaneau, a., conrad, m., deloffre, r., lupertosinni, e., masse, p., peybernes, b., radoičić, r., sokač, b. & velić, i. (1991): distribution of lower cretaceous foraminifera and dasyclad algae of the adriatic plate. – sec. internat. symp. on the adriatic carb. platf., abstracts, 22, zadar. barattolo, f. (1991): chapter 22. mesozoic and cenozoic marine benthic calcareous algae with particular regard to mesozoic dasycladaleans. – in: riding, r. (ed.): calcareous algae and stromatolites. springer-verlag, berlin, p. 504–540, 6 fi gs., 7 pls. sokač, b. & jelaska, v. (1991): salpingoporella polsaki n.sp. (calcareous algae; dasycladaceae) from the cenomanian deposits of the island of brač (salpingoporella polsaki n.sp. (vapnenačka alga; dasycladaceae) iz cenomana otoka brača). – geol. vjesnik, 44, 1– 6, 1 pl., zagreb. sremac, j. (1991): zona neoschwagerina craticulifera u srednjem velebitu (zone neoschwagerina craticulifera in the middle velebit mt. (croatia, yugoslavia)). – geologija, 34 (1991), 7–55, 13 pls., ljubljana. sokač, b. (1992): two new species of calcareous algae (dasycladaceae) from the upper dogger of southern dalmatia (croatia) (dvije nove vrste vapnenačkih alga (dasycladaceae) iz gornjeg dogera južne dalmacije (hrvatska)). – geol. croat, 45, 15–24, 2 pls., zagreb. sokač, b. (1993): salpingoporella robusta n. sp. (calcareous algae; dasycladales) from the upper barremian – lower aptian of mt. biokovo, croatia. – geol. croat, 46/2, 175–180, 1 pl., zagreb. grgasović, t. (1995a): revision of genera physoporella, steinmann and oligoporella, pia (dasycladales, green algae). – 6th international symposium on fossil algae and carbonate platforms, abstracts, 15, ankara. grgasović, t. (1995b): stratigraphy of middle and upper triassic deposits from zumberak mt. (w croatia). – 6th international symposium on fossil algae and carbonate platforms, abstracts, 34, ankara. radoičić, r. (1995): on the age of limestone with actinoporella kukoci radoičić, 1975 and praturlonella salernitana barattolo, 1978 (dasycladacean algues). – rev. paleobiol., 14/1, 95–105, 1 fi g, 4 pls., gèneve. sokač, b. & grgasović, t. (1995): dissocladella bystrickyi n.sp., a new calcareous alga (dasycladaceae) from upper triassic dolomites of mt. medvednica (northern croatia). – geol. croat, 48/1, 1–7, 2 pls., zagreb. sokač, b. (1996): taxonomic review of some barremian and aptian calcareous algae (dasycladales) from the dinaric and adriatic karst regions of croatia. – geol. croat, 49/1, 1–79, 22 pls., zagreb. grgasović, t. (1997): upper triassic biostratigraphy and algae from žumberak (croatia). – geol. croat, 50/2, 201–214, 1 fi g., 2 pls., zagreb. sremac, j. & aljinović, d. (1997): upper palaeozoic fossils from clastic sedimentary rocks in the gorski kotar region. – geol. croat, 50/2, 187–199, 3 pls., zagreb. sgrosso, a., esposito, p. & radoičić, r. (1998): the occurence of salpingoporella milovanovici radoičić (dasycladales) in the cenomanian of south apennines and dinarides. – geologija, 40, 113–117, 2 pls., ljubljana. sokač, b. & grgasović, t. (1998): asterocalculus heraki n.gen. n.sp., a new calcareous alga (gymnocodiaceae) from the upper triassic hauptdolomite of žumberak, north croatia. – facies, 38, 197– 206, 3 fi gs., 1 tab., 3 pls., erlangen. grgasović, t. & sokač, b. (1999a): teutloporella pia and euteutloporella de castro (dasycladales, green algae) from the triassic of croatia. – in: mu xinan, yuan xunlai & kershaw, s. (eds.): seventh international symposium on fossil algae (oct. 13–17, 1999, nanjing), abstracts, 23–24, nanjing. grgasović, t. & sokač, b. (1999b): triassic dasycladales from croatia: a review. – in: mu xinan, yuan xunlai & kershaw, s. (eds.): seventh international symposium on fossil algae (oct. 13–17, 1999, nanjing), abstracts, 27–28, nanjing. grgasović, t., sokač, b. & halamić, j. (1999): salpingoporella scopuliformis n. sp. (dasycladales, green algae) from the middle triassic of croatia. – in: mu xinan, yuan xunlai & kershaw, s. (eds.): seventh international symposium on fossil algae (oct. 13–17, 1999, nanjing), abstracts, 25–26, nanjing. granier, b.r.c. & grgasović, t. (2000): les algues dasycladales du permien et du trias. nouvelle tentative d’inventaire bibliographique, géographique et stratigraphique (permian and triassic dasyclad algae. bibliographic, geographic, and stratigraphic reappraisal). – geol. croat, 53/1, 1–197, 27 fi gs., 1 tab., zagreb. grgasović, t. & sokač, b. (2000): fosilne asocijacije dazikladalnih algi u trijasu hrvatske (fossil associations of dasycladalean algae in the triassic of croatia). – in: vlahović, i. & biondić, r. (eds.): 2. hrvatski geološki kongres (second croatian geological congress) (cavtat – dubrovnik, 17–21.05.2000.), zbornik radova (proceedings), 189–191, 1 fi g., zagreb. sokač, b. (2000): salpingoporella donatae n.sp. (dasycladales) from upper cretaceous limestone of the environs of primošten (dalmatia, croatia). – geol. croat, 53/1, 199–207, 1 fi g., 1 tab., 3 pls., zagreb. grgasović, t. (2001): triassic dasycladales from the reefeal facies: examples from nw croatia. – in: bucur, i.i. & tanţǎu, i. (eds.): 4th regional symposium of i.f.a.a. (algae and carbonate platforms in romania) (august 29–september 5, 2001, cluj–napoca, romania), programme and abstracts, p. 27, cluj–napoca. sokač, b. (2001): lower and middle liassic calcareous algae (dasycladales) from mt. velebit (croatia) and mt. trnovski gozd (slovenia) with particular reference to the genus palaeodasycladus (pia, 1920) 1927 and its species. – gol. croat, 54/2, 133–257, 8 fi gs., 17 tabs., 42 pls., zagreb. grgasović, t., sokač, b. & halamić, j. (2002): scinderella scopuliformis nov.gen., nov.sp. (dasycladales, green algae) from the middle triassic of croatia (scinderella scopuliformis nov.gen., nov.sp. (dasycladales, algues vertes) du trias moyen de croatie). – geobios, 35, 303–312, 5 fi gs., lyon. geologia croatica geologia croatica 61/2–3 72 radoičić, r. (2002): new dasycladalean alga from the upper cretaceous of the island pašman (croatia). – geol. anali balk. poluostr., 64, 83–87, 1 pl., beograd. tišljar j., vlahović i., velić i. & sokač, b. (2002): carbonate platform megafacies of the jurassic and cretaceous deposits of the karst dinarides. – geol. croat., 55/2,139–170, zagreb. grgasović, t. (2003): revizija rodova physoporella steinmann i oligoporella pia (dasycladales) (revision of genera physoporella steinmann and oligoporella pia (dasycladales)). – unpublished phd thesis, faculty of science, zagreb university, viii+484 p., 70 fi gs., 40 tabs., 26 pls., 1 suppl. grgasović, t. & sokač, b. (2003a): review on fossil dasycladalean associations in the triassic of croatia. – in: yuan xunlai & mu xinan (eds.): fossil algae and stromatolites. acta micropal. sinica, 20/1, 75–79, 1 fi g., nanjing. grgasović, t. & sokač, b. (2003b): dasycladales in the stratigraphy of the croatian dinarides mts. – in: braga, j.c. & aguirre, j. (eds.): 8th international symposium on fossil algae, abstracts, 27–28, granada. radoičić, r. (2004): note on paleocene algae in dubrovnik coast (adriatic carbonate platform). – geol. anali balk. poluostr., 65 (2002–2003), 29–45, 1 fi g., 1 tab., 6 pls., beograd. sokač, b. & grgasović, t. (2004): megaporella nikleri n.sp., a new calcareous alga (dasycladales) from the upper barremian of mt. biokovo, croatia. – riv. ital. paleontol. stratigr., 110/3, 651– 658, 4 fi gs., 2 pls., milano. sokač, b. (2004): on some peri-mediterranean lower cretaceous dasyclad species (calcareous algae; dasycladales) previously assigned to different genera. – geol. croat, 57/1, 15–53, 3 fi gs., 3 tabs., 12 pls., zagreb. goričan s., halamić j., grgasović t. & kolar-jur kovšek t. (2005): stratigraphic evolution of triassic arc-backarc system in northwestern croatia. – bull. soc. géol. france, 176/1, 3–22, 5 fi gs., 3 pls., paris. grgasović, t. & sokač, b. (2005): new dasyclads from the anisian of lika (croatia). – in: fugagnoli, a. & bassi, d. (eds.): 5th regional symposium of the international fossil algae association (30th–31st august 2005, ferrara, italy), abstracts. museologia sci. nat., 24, ferrara. sokač, b. (2005): linoporella vesiculifera n.sp., a new calcareous alga (dasycladales) from the upper barremian of mt. biokovo (karst dinarides, croatia). – geol. croat., 58/2, 119–131, zagreb. sremac, j. (2005): equatorial shelf of the palaeozoic supercontinent – cradle of the adriatic carbonate platform. – geol. croat, 58/1, 1–19, zagreb. carras, n., conrad, m.a. & radoičić, r. (2006): salpingoporella, a common genus of mesozoic dasycladales (calcareous green algae). – rev. paléobiol., 25/2, 457–517, genčve. husinec, a. & sokač, b. (2006): early cretaceous benthic associations (foraminifera and calcareous algae) of a shallow tropical-water platform environment (mljet island, southern croatia). – cretac. res., 27/3, 418–441. grgasović, t. & vlahović, i. (ed.) (2007): 9th international symposium on fossil algae, field-trip guidebook and abstracts. hrvatski geološki institut – croatian geological survey, vi+262 p., zagreb. * papers on investigations in other countries manuscript received july 15, 2008 revised manuscript accepted october 15, 2008 08-slagintweit.indd 81 �ab stra ct some new and poorly known larger benthic foraminifera are described from middle jurassic (upper aalenian–bajocian) shallow-water limestones of the croatian karst dinarides. cymbriaella lorigae fugagnoli is reported for the fi rst time outside its type-locality, the upper pliensbachian of the southern alps. new taxa described include bosniella bassoulleti n. sp. and dubrovnikella septfontainei n. gen., n. sp. (family biokovinidae). both cymbriaella lorigae fugagnoli and everticyclammina praevirguliana fugagnoli are reported for the fi rst time from middle jurassic strata. the new fi ndings enlarge the stratigraphic ranges and allow further insights into the phylogenetic evolution of the larger benthic foraminifera during the early to middle jurassic period. keywords: benthic foraminifera, taxonomy, phylogeny, middle jurassic, karst dinarides, croatia new and poorly known middle jurassic larger benthic foraminifera from the karst dinarides of croatia � felix schlagintweit1 and ivo velić2 1lerchenauerstr. 167, d-80935 münchen, germany; (ef.schlagintweit@t-online.de) 2croatian geological survey, sachsova 2, 10000 zagreb, croatia; (ivo.velic@hgi-cgs.hr) doi: 104154/gc.2011.08 geologia croatica 64/2 81–99 15 figs. 3 tabs. zagreb 2011 geologia croaticageologia croatica 1. introduction larger benthic foraminifera are widely distributed in jurassic shallow-water carbonates of the karst dinarides. they were studied and illustrated in many palaeontological and/ or biostratigraphical papers, mostly during the ’60s and ’70s of the 20th century, especially from the lower jurassic and partly from the middle jurassic (bathonian) and upper jurassic (oxfordian and kimmeridgian) (e.g. radoičić, 1966; nikler & sokač, 1968; gušić 1969a, b, 1977; velić, 1977, 2007; gušić & velić, 1978; velić & sokač, 1978). in the earlier middle jurassic, in the croatian part of the karst dinarides, gutnicella cayeuxi (lucas) was found together with the most common species bosniella croatica (gušić) in biokovo and in the vicinity of karlovac (central croatia) (anić, 1962; radoičić, 1966; gušić 1969b). velić (2005) reported on aalenian–bajocian foraminiferal assemblages of southern croatia, from biokovo mt. and the dubrovnik area, including important species such as gutnicella cayeuxi, timidonella sarda bassoullet, chabrier & fourcade, spiraloconulus giganteus cherchi & schroeder, pseudodictyopsella jurassica septfontaine & de matos, marzoella fi ccarellii chio cchini & mancinelli, paravalvulina complicata septfontaine, and pseudoeggerella elongata septfontaine. based on these fi ndings, four chronostratigraphic zones within older middle jurassic deposits were established by velić (2005). later, velić (2007) established seven biostratigraphic zones based on larger benthic foraminifera. during these investigations of aalenian–bajocian limestones of biokovo mt. and the dubrovnik area, several ta xa not previously reported from croatia were observed, including one new genus and two new species described here. 2. geological setting during the early middle jurassic, two sedimentary provinces with signifi cantly different environments may be distinguish ed within the area of the adriatic carbonate platform (vlahović et al., 2005, for details). one encompasses platform marginal and peri-marginal dynamics, areas strongly infl uenced by currents and waves, with the occasional degeologia croatica 64/2geologia croatica 82 velopment and destruction of patch reefs. the second area belongs to the inner platform characterized by protected environments with a steady and uniform sedimentation of thick layers of carbonate mud. in marginal areas, the most common deposits are thick-bedded ooid-intraclast-bioclastic-ske letalpelletal grainstones and packstones, in places rud stones, rich in fossil remains. in contrast, thick-layered mudstones, ra re ly wackestones and packstones with very few fos sil remains were deposited in the inner platform area. in the area of southern croatia, southeast of split, as well as in montenegro and northern albania, middle jurassic se diments were deposited in the fi rst, marginal province. this area includes the localities in biokovo mt. and in the vicinity of dubrovnik (fig. 1) where the investigated foraminiferal fauna has been found, including the new taxa described in the present paper. aalenian–bajocian carbonates of southern croatia crop out in the frontal part of the sequence of mesozoic deposits uplifted and thrusted over the palaeogene clastic sediments. carbonates are in direct contact with clastic deposits, stratigraphically ranging from the late triassic to the middle jurassic. the reversed-overthrust contact extends from the northwestern part of biokovo mt. to the east of konavle, along the border with montenegro. it is morphologically expressed by the steep slopes of biokovo mt., the hills around dubrovnik and montenefigure 1: geographic position of the investigated sections in croatia (asteriks). os = osojnik village 5 km north of dubrovnik, sl = slano village about 25 km nw of dubrovnik, bst = biokovo section. figure 2: local geographic map (dubrovnik sheet, no. 625-3-1), scale 1:25.000 with the position of the osojnik section and sample o 32 (= o 10) containing the holotype of bosniella bassoulleti n. sp. þ schlagintweit & velić: new and poorly known middle jurassic larger benthic foraminifera from the karst dinarides of croatia geologia croatica 83 gran coastal mountains. given the position of the jurassic sediments, they are intensely tectonically disturbed, favouring heavy karstifi cation, disintegration and sliding over the steep slopes of palaeogene clastics. sections with fully preserved successions of jurassic units are rare. lower jurassic deposits were mostly tectonically reduced, and are occasionally entirely absent, so that only middle jurassic deposits are in contact with the palaeogene clastic rocks. contact between middle and upper jurassic carbonates are also tectonically disturbed and continuous transition between them is very rare. 2.1. the osojnik section the middle jurassic deposits of the osojnik section were investigated along the road connecting the village of osojnik with dubrovnik (figs. 1–2). about 2 km south-southeast of the village, the road crosses the tectonic boundary between the folded lower jurassic (pliensbachian) lithiotis limestones, (about 30 m in thickness), and massive aalenian ooid grainstones. the latter are overlain by bioclastic-oncoidal and intraclast grainstones, in places rudstones with recrystallized skeletons and debris of calcareous algae, molluscs figure 3: lithostratigraphy of the osojnik section and distribution of important larger benthic foraminifera. geologia croatica 64/2geologia croatica 84 (mainly gastropods), corals, stromatoporoids, foraminifers, etc. (fig. 3). within this section, approximately 40 m above the ooid grainstones, an approximately 20 m thick zone of late-diagenetic dolomite occurs, followed by bioclastic-oncoidal grainstones containing the fi rst specimens of bosniella croatica and then bosniella bassoulleti n. sp. (fig. 3). the se limestones are overlain by approximately 20 m of mud stone and again bioclastic/intraclastic-oncoidal grainstones which, in addition to the aforementioned biokovinids, includes (in the order of appearance) timidonella sar da and spiraloconulus giganteus. above the layers with timido nel la, the following ~60 m of the succession is characterized by the fi rst appearance of the biostratigraphically signifi cant dasy cla dale selliporella donzellii (sartoni & crescen ti), and by the maximum frequency of b. bassoulleti n. sp. with in this interval, sample os–10 (= o–32; fig. 2) contains the holotype of this species. between the last appearance of b. bassoulleti n. sp. and the fi rst occurrence of the younger bajocian species paravalvulina complicata there are no other signifi cant foraminifera. within the range of p. complicata, the species pseudoeggerella elongata septfontaine with an upper bajocian–bathonian range and pfenderella arabica redmond of a wider stratigraphic range appear. the thickness of the upper aalenian and bajocian carbonates, between the aalenian ooid limestones and the bathonian limestones is about 360 m. 2.2. the slano section the middle jurassic part of the slano section is measured northeast of slano on the slopes of the kosmatovica and kolomnić hills (fig. 4). as in the osojnik profi le, the middle jurassic succession starts with aalenian ooid limestone, who se thickness is unknown due to the tectonic contact with the lower jurassic carbonates. the ooid limestones are followed by approximately 20 m of layered mudstones and wacke stones. in the next 270 m of the profi le, massive latediagenetic dolomites, and oncoid-intraclastic-bioclastic grainstones prevail, with rudstones in places in alternation with skeletal-intraclastic grainstones/rudstones. these deposits are mostly thick layered (0.6 m to 1.5 m) and rarely even massive. there are interbeds or thin intervals of mud-supported intraclastic-skeletal limestones, prevailing after the aforementioned massive late-diagenetic dolomites at the end of the bajocian and beginning of the bathonian limestones. fossil remains and debris belong mostly to molluscs (predominantly gastropods), corals, echinoderms, stromatoporoids, calcareous algae, and foraminifera. in the initial part of the sequence and within a further ~60 m thick interval, a rich assemblage of index foraminifera has been observed. in addition to bosniella croatica, which starts within the ooid limestones, gutnicella cayeuxi, cymbriaella lorigae, dubrovnikella septfontainei n. gen., n. sp., pseudocyclammina may n ci hottinger and bosniella bassoulleti n. sp. appear almost in the same horizon (fig. 5). most of the cited species have a rather narrow stratigraphic range, so that above this biohorizon, for another 30 m, only g. cayeuxi extends until the appearance of spiraloconulus perconigi (alleman & schroeder). after a further 20 m, timidonella sarda was determined, and around 70 m above that, the ran ge of the dasycladalean alga selliporella donzellii begins. in the next 30 m of the column, together with s. donzellii, the only foraminifera occurring is b. croatica (also indicating its last appearance) and b. bassoulleti n. sp., the last appearance of which is determined after a further 30 m. in the next 70 m, there are no signifi cant microfossils except s. don zellii. after 15–20 m of massive late-diagenetic dolomite, skeletal-intraclastic grainstones and skeletal wackestones con taining pfenderella arabica occur; 20 m above pseudoeggerella elongata and fi nally an additional 20 m or so, a bathonian as semblage with paleopfenderina salernitana, etc. occurs (fig. 5). the thickness of the upper aalenian and bajocian carbonates in the slano cection between the aalenian ooid limestones and the bathonian limestones is about 350 m. 2.3. the biokovo mount section the biokovo mt. profi le was measured east of tučepi along the staza–lemišini doci road in the biokovo nature park (fig. 6). as in the case of the osojnik and slano sections, the oldest middle jurassic carbonates are thick layered and massive ooid limestones of aalenian age. the lithological features of the upper aalenian–bajocian carbonates of the biokovo section, in continuous succession over ooid limestones, are very similar to those in the osojnik and slano sections. in the older parts, bioclastic-skeletal-oncoid and figure 4: local geographic map (slano sheet, no. 624-2-4), scale 1 : 25.000 with the position of the slano section, the type-locality of dubrovnikella septfontainei n. gen. n. sp. schlagintweit & velić: new and poorly known middle jurassic larger benthic foraminifera from the karst dinarides of croatia geologia croatica 85 intraclastic grainstones to rudstones prevail, in places with interbedded oolites and skeletal wackestones and mudstones. among the skeletal remains there is fossil debris and sections of molluscs, corals, stromatoporoids, algae, and foraminifers. skeletal and bioclastic grainstones/mudstones are most common in the younger part of the column, and they often alternate with intraclastic grainstones. local emergen ce ho rizons rarely occur. figure 5: lithostratigraphy of the slano section and distribution of important larger benthic foraminifera. geologia croatica 64/2geologia croatica 86 among the foraminifera, bosniella croatica and gutnicella cayeuxi were already present in the ooid limestones, over lain by about 50 m of thick-layered skeletal-oncoidal grainstones with interbedded skeletal wackestones, followed by another, but thinner package, i.e. about 10 m thick, of ooid limestones. within the interval between the base and these thinner ooid limestone beds there are bioclastic oncoid and skeletal grainstones/packstones with everticyclammina praevir guliana fugagnoli (fig. 7). above the thin ooid limestones there is a sequence of thick-bedded, oncoidal, skeletal grainstones with rare g. cayeuxi and more frequent ti mi donella sarda. the latter is found in the younger strata, beneath the local emergence horizon, characterized by the fi rst occurrences of bosniella bassoulleti n. sp. and spiraloconulus giganteus. among the cited species, b. croatica, b. bassoulleti n. sp. and s. giganteus continue after emergence, while 15 m above the emergence the alga selliporella donzellii appears. in the middle part of the bajocian column, about 80 m above the mentioned emergence horizon, pseudodictyopsella jurassica and marzoella fi ccarellii occur, these being up to now their fi rst, and only occurrences in the karst dinarides. approximately 40 m above the last occurrence of s. giganteus, after a further 60 m of the column, b. croatica disappears, and after another 30 m also b. bassoulleti n. sp. disappears. in the following 40 m of the column to the fi rst occurrence of pfenderella arabica, there are no important foraminiferal species. about 10 m above, in the topmost bajocian beds, paravalvulina complicata and pseudoeggerella elongata appear, and after a further ca. 10 m there is an emergence breccia with black pebbles (originating from marsh deposits on the tidal fl at). about 15 m above the emergence horizon the next emersion level follows, and then layers with paleopfenderina salernitana and other bathonian foraminifera. the thickness of the upper aalenian and bajocian carbonates in the biokovo profi le between the aalenian ooid limestones and the bathonian limestones cannot be accurately determined due to tectonic disintegration and gentle folding, but is estimated at about 350 m. 3. systematic palaeontology the systematics follows the “year 2000 classifi cation” of kaminski (2004). for the diagnosis of genera, we essentially follow loeblich & tappan (1987). the description main ly follows the terminological compendium of hottin ger (2006). class foraminiferida order loftusiida kaminski & mikhalevich, 2004 suborder orbitolinina kaminski & mikhalevich, 2004 superfamily pfenderinacea smout & sudgen, 1962 family hauraniidae septfontaine, 1988 subfamily hauraniinae septfontaine, 1988 genus cymbriaella fugagnoli, 1999 cymbriaella lorigae fugagnoli, 1999 (figs. 8a–g, fig. 14a pars) description: large test consisting of a more or less plani spirally coiled initial portion (1.5 to 2 whorls) and a rather large uncoiled portion with 4 to 5 chambers, separated by thick septa. in the uncoiled portion, chamber width increases moderately. test wall thick, alveolar with incorporated foreign material (e.g., peloids, small foraminifera). single foramen in the initial part; in longitudinal sections rather broad multiple (up to 4–5) foramina are discernible in the uncoiled portion (fig. 8d). dimensions see table 1. remarks and comparisons: cymbriaella lorigae was described from the pliensbachian of the southern alps (fugagnoli, 1999) and the stratigraphic range can now be extended to include the upper aalenian-lower bajocian interval. besides the italian and croatian records, the species was recently also reported from the liassic of turkey (özkaymak et al., 2010). the middle jurassic specimens from croatia agree closely with the lower jurassic material described by fugagnoli (1999). microfacies: intraclastic packto rudstones with debris of molluscs, and gastropods. the associated foraminifera infigure 6: local geographic map (makarska sheet, no. 126-1-3), scale 1 : 25.000 with the position of the biokovo section. schlagintweit & velić: new and poorly known middle jurassic larger benthic foraminifera from the karst dinarides of croatia geologia croatica 87 clude dubrovnikella septfontainei n. gen., n. sp. (rare), bosniella bassoulleti n. sp. (rare), gutnicella cayeuxi (rare), agerina martana (farinacci) (very rare), small textularids and trochospiral forms, e.g., tetrataxids (common) and a triserial ataxophragmiid foraminifer gen. et sp. indet. (common) (fig. 9). thaumatoporellaceans with free, attached, and cryptobiotic specimens are abundant (see schlagintweit & velić, 2011). occurrences: slano section (figs. 4, 5); rare at biokovo mt. section (figs. 6, 7). suborder biokovinina kaminski, 2004 superfamily biokovinacea gušić, 1977 family biokovinidae gušić, 1977 remarks: bosniella was removed from the biokovinidae by mikhalevich (2004) due to the lack of endoskeletal figure 7: lithostratigraphy of the biokovo section and the distribution of important larger benthic foraminifera. geologia croatica 64/2geologia croatica 88 structures as reported from bosniella (see tab. 2). this view was corrected in the “year 2000 classifi cation” of kaminski (2004) with the creation of the suborder biokovinina kaminski and the maintenance of bosniella within the bio kovinidae by giving the wall structure a higher hierarchy than the presence/absence of the endoskeleton. the absence/presence of endoskeletal structures can instead be taken into consideration to differentiate the two subfamilies within the biokovinidae. genus bosniella gušić, 1977 bosniella bassoulleti n. sp. (figs. 10/a-q, figs. 11/a-m, fig. 12a) origin of the name: dedicated to jean-paul bassoullet for his numerous outstanding contributions to the knowledge of jurassic larger benthic foraminifera. holotype: specimen in equatorial section fi gured in (fig. 10d). thin section os 10. isotypes: specimens fi gured in (figs. 10a–c, e–q, figs. 11a–m). thin sections o 32/a and –/b, sl 2, sl 2/1, sl 3a/3, sl 3b/2, sl 4a, sl 4a/1, sz 64/4, sz 64/5 (for abbreviations of sample locations see fig. 1). depository: croatian geological survey, sachsova 2, 10000 zagreb, croatia. type-locality: dubrovnik area, southern croatia, the road connecting the village of osojnik with dubrovnik (figs. 2). type-level: thick-bedded, light-brownish coloured to white limestone, skeletal and bioclastic-oncoidal grainstone/packstone (figs. 2, 3; samples o-32 and os-10) of back reef environment with numerous sections of b. basfigure 8: cymbriaella lorigae fugagnoli. upper aalenian–lower bajocian of the croatian karst dinarides. a) equatorial section, uncoiled portion with 5 chambers. note incorporation of small particles (peloids, foraminifera) into the wall and septa. b) equatorial section, slightly oblique. c) axial section, slightly oblique. d–e) equatorial sections with 5 and 3 chambers in the uncoiled portion. note single aperture in the coiled part becoming multiple in the uncoiled part and both thick wall and septa. f ) detail of a showing alveolar wall. g) oblique section through the uncoiled part. scale bar 1mm, except f 0.5 mm. thin sections: a sl 3a/3, b sl 3b/2, c sl 3b/1, d sl 5b2, e sl 3b/2, g sl 3a. schlagintweit & velić: new and poorly known middle jurassic larger benthic foraminifera from the karst dinarides of croatia geologia croatica 89 soulleti, rare spiraloconulus giganteus, siphovalvulina variabilis, triserial ataxophragmiid foraminifer gen. et sp. indet. (fig. 9), bioclasts of thaumatoporellaceans, corals, molluscs, etc. diagnosis: a representative of the genus bosniella showing a planispiral discoidal test, varying from partly involute and widely umbilicate to involute, often with slightly undulating growth direction and a prominent uncoiled portion. chambers numerous in the coiled part, becoming moderately broader during growth, in the uncoiled portion either constant in width or expanding. foramen single, interiomarginal in the coiled part becoming multiple in the uncoiled part. wall microgranular with keriothecal texture. description: test free, lenticular, more or less planispirally coiled initially, with 2–2½ whorls and a maximum of up to 14 chambers in the last whorl in adult specimens; the adult part may be uncoiling. the coiling is often not exactly planispiral but may show a slight inclination towards the plane of the previous whorl or an oscillating inclination that may result in an sor sigmoid shape in axial sections (figs. 11b, i, k). in most cases, the umbilicus is well pronounced (e.g. fig. 10g, upper specimen, fig. 11c, m). the fi rst chamber (protoconch) is subsphaerical (diameter up to 0.11 mm), enclosed by a thin wall (membrane) with a thickness of about 0.005 mm (fig. 12a). in the coiled portion, chamber width gradually increases, often distinctly so in the last half of the fi nal whorl, resulting in a more or less asymmetry in axial sections (fig. 10g, upper specimen, figs. 11c, e). in equatorial sections, the chambers are becoming higher during ontogeny but also show a fl attened top with angular peripheries; in the older parts, chamber peripheries are more rounded (figs. 10a–b, d, 11a). in the same way, the diameter of the single foramen near the chamber base also increases. sutures between subsequent chambers are poorly developed (e.g. figs. 10a, 11a). the ultimate chambers often show upward growth towards the previous whorl resulting in a massive thickening of the chamber wall (figs. 10a, 11a). this seems to be the preparation of the test to uncoil, in broadening the junction between the coiled and uncoiled parts (figs. 10e–f). the planispiral stage is often followed by an uncoiled, more or less rectilinear, stage. the shape may vary from cytable 1: dimensions of cymbriaella lorigae fugagnoli, upper aalenian– lower bajocian of croatia. d = diameter coiled portion (in equatorial sections), dup = diameter uncoiled portion, hup = height uncoiled portion, h = total test height (or length), n = number of chambers in the uncoiled portion. figure 9: triserial ataxophragmiid foraminifera gen. et sp. indet. a) longitudinal section. b) oblique longitudinal section. c) oblique transverse section; note tiny sphaeroids (?coccoid cyanobacteria) inside the chamber (arrow). d) transverse section. scale bars 0.5 mm. thin sections: a sl 3/b, b sl 3a, c o 32/b, d sz 64/3. table 2: systematic position of the genera bosniella gušić and biokovina gušić within the foraminiferida after loeblich & tappan (1987), mikhalevich (2004) and kaminski (2004). geologia croatica 64/2geologia croatica 90 figure 10: bosniella bassoulleti n. sp. upper aalenian–lower bajocian of the croatian karst dinarides. a–c, e–q isotypes. d holotype. a–d) equatorial sections, in part slightly oblique. holotype specimen (d) with uncoiled part consisting of three chambers; note multiple foramina evolving in the uncoiled portion (arrows). e–f) specimens with prominent uncoiled part with 6 (?7) chambers in f. in e the chambers of the uncoiled part widen continuously, whereas in f the width remains more or less constant. g–h) two specimens in diff erent sections. note distinct biumbonal depression of the upper specimen in g cut in axial section and also the change of growth direction in the ultimate whorl. i–m) oblique sections. n) subaxial section; note irregular planispiral coiling resulting in a bent test. o) specimen with large uncoiled portion. p) two specimens, small juvenile specimen above in subaxial section, the other one below in oblique section. q) equatorial section, slightly oblique; coiled portion showing 2 ½ whorls, uncoiled portion with 4 chambers. scale bar 0.5 mm for all pictures. thin sections: a, i–j, p o 32b, b, d, g os10/1, c, h o 32a, e sz 64/4, f sl 2/1, k o 35, l sl 2/1, m sl 4/1, n, q sl 4a, o sz 64/5. schlagintweit & velić: new and poorly known middle jurassic larger benthic foraminifera from the karst dinarides of croatia geologia croatica 91 lindrical with chamber width remaining more or less constant (e.g. fig. 10f), to expanding (cylindroconical), with chamber width increasing successively (fig. 10o). occasionally, there are specimens displaying chambers not rectilinearly arrang ed, but with varying growth directions (with respect to the previous chamber). successive change of chamber growth direction may result in an overall sigmoid appearance (fig. 10n). chamber shape of the uncoiled part in axial sections is variable, mostly hemispherical with fl at or concave base, in cases also with fl attened top (trapezoid, e.g. third ultimate chamber in fig. 10e). the distal end of the uncoiled part is mostly broadly rounded (fig. 10f, o) or more rarely acutely rounded (fig. 10e). the septa of the uncoiled portion are pierced by several (“multiple”) foramina (fig. 10d), often not detectable. in oblique sections, the chamber lumina are in direct contact to each other giving the impression of a broad single foramen in the centre (figs. 10o, q). the test wall is fi nely agglutinating; the fi ne keriothekal structure is indistinct and not always detectable (fig. 11d), presumably due to diagenetic processes. remarks and comparisons: the differences of bosniella bassoulleti n. sp. to the other three species of the genus bosniella can be summarized as follows: b. oenensis gušić (pliensbachian of bosnia): as axial sections were not available in the material on which the original description was based, information on the type of coilfigure 11: bosniella bassoulleti n. sp. upper aalenian–lower bajocian of the croatian karst dinarides. a–m isotypes. a) equatorial section; on the right gutnicella cayeuxi (lucas). b–c) (sub)axial sections, in part slightly oblique. note distinct biumbonal depression in c and oscillating coiling direction in b. d) magnifi cation from the holotype specimen of fig. 10d showing the poorly recognizable keriothecal wall structure. e–i) (sub)axial sections, in part slightly oblique. note signifi cant increase in chamber width within the ultimate whorl in e and f. j) broken uncoiled portion; note the more or less constant chamber width. k–m) (sub)axial sections. note sigmoidal test bending of specimen shown in k. scale bar 0.3 mm in d, all other pictures 0.5 mm. thin sections: a sl 4a/1, b, i sl 2/1, c sl 3/b/2, d os 10/1, e, f, g, h, m o 32/b, j sl 3a/3, k sl 4/4, l os 10. geologia croatica 64/2geologia croatica 92 ing (involute or evolute) were not provided. gušić (1977, p. 14) further remarked that “some specimens are likely to have developed an uncoiled stage”. with respect to these two points, the original description has been completed by fugagnoli & loriga broglio (1998), based on material from the pliensbachian of the southern alps. accordingly, the coiling is involute with a marked umbilical depression and a prominent uncoiled adult part of the test is well developed in most specimens (see also boudagherfadel & bosence, 2007). outer test dimensions of b. oenensis and b. bassoulleti n. sp. are comparable. the photographs provided by gušić (1977) and fugagnoli & loriga broglio (1998) show that the number of chambers in the last whorl, being ~ 7 to 9, is reduced compared to b. bassoulleti n. sp. (11 to 14). this difference is caused by more massive septa in b. oenensis (0.12–0.13 mm, acc. to fugagnoli & loriga broglio, 1998) and more delicate in b. bassoulleti n. sp. (thickness 0.04–0.08 mm), with the thickest septa observed in the uncoiled portion. fugagnoli & loriga broglio (1998) stated that the chambers within the uncoiled part are “progressively expanding”. in b. bassoulleti n. sp. we observed both specimens with chamber width in the uncoiled part remaining constant (fig. 10f), and others with increasing width (fig. 10o). b. croatica (gušić) (early-middle jurassic of croatia = former mesoendothyra croatica, according to bassoullet, 1994): above all, this species is smaller with diameter of the coiled part of 0.5 mm and length (= height) of test (including uncoiled portion) of 0.75 to 1.0 mm (see gušić, 1969, p. 67). another difference is that the aperture in the coiled part of b. croatica is positioned at the very base of the chambers, whereas in b. bassoulleti n. sp. it is situated somewhat above, more towards the centre of the septum. b. fontainei bassoullet (aalenian-bajocian of thailand) is distinguished from b. bassoulleti n. sp. by a distinctly less developed uncoiled stage, and a more globular test with smaller biumbonal depressions. the globular test results from a more involute type of coiling, with largely overlapping whorls, as visible in axial sections (e.g., bassoullet 1994, pl. 1/8–9, 12). both bosniella croatica and bosniella fontainei display a test dimorphism (gušić, 1977; bassoullet, 1994; fu gagnoli & loriga broglio, 1998). as discussed by fugagnoli (2004, fig. 5), the occurrence/absence of tests showing dior trimorphism in complex large benthic lower jurassic foraminifers is triggered by the trophic regime. the genera cymbriaella, bosniella and lituolipora are interpreted as characterizing oligotrophic conditions. for bosniella croatica, gušić (1977, p. 14) remarks that the dimorphism concerns “mainly the size of the tests and of the proloculus, while the general shape and basic growth pattern is the same for both types”. furthermore, gušić states that in microspheric tests “the proloculus could not be observed ” and “no uncoiled stage has been observed ”. in accordance with this, fugagnoli & loriga broglio (1998, p. 64) also noticed “a more developed uncoiled stage of megalospheric forms”. in bosniella fontainei it seems to be just the opposite, with uncoiled megalospheric and coiled microspheric forms. a discrete dimorphism is not well pronounced in bosniella bassoulleti; in fact, the assumed megalospheric specimens with subsphaerical proloculus are observable in both coiled (fig. 11f, m) and uncoiled (fig. 10d) forms. specimens sectioned in the median plane without a detectable proloculus are assumed to represent microspheric forms. a possible difference in test morphology seems to be that microspheric forms are more fl attened lenticular than the macrospheric ones. stratigraphy: bosniella bassoulleti appears within the upper part of the stratigraphic range of timidonella sarda and gutnicella cayeuxi, and has its maximum abundance immediately above the disappearance of these two species (see velić, 2007 for details). it disappears a little below the level with mass abundance of selliporella donzellii, indicative of the bajocian–bathonian interval (e.g. granier & deloffre, 1994). for instance, a selliporella donzellii cenozone (bajocian) has been established in the taurus mountains of turkey (altiner & septfontaine, 1979), later modifi ed to a timidonella sarda-selliporella donzelli zone (ekmekçi & altiner, 2008). according to these data, the stratigraphic range of b. bassoulleti can be considered as late (or latest) aalenian–?early bajocian. microfacies: same as for cymbriaella lorigae (sl samples). occurrences: osojnik section (figs. 2, 3) and slano section (figs. 4, 5). suborder biokovinacea gušić, 1977 superfamily biokovinacea gušić, 1977 family biokovinidae gušić, 1977 dubrovnikella n. gen. origin of the name: the genus refers to the city of dubrovnik on the adriatic coast of croatia. type species: dubrovnikella septfontainei n. gen. n. sp. diagnosis: test free, irregularly planispirally to streptospirally coiled in early stage, nautiloid in form; later a slight tendency to uncoil may be present. wall thin, fi nely agglutinating, with inner alveolar layer and outer imperforate epidermis. alveoli simple, more or less parallel and more or less of equal diameter. septa short and not alveolar. no enfigure 12: simple embryonic apparatus of bosniella bassoulletti n. sp. (a) and complex embryonic apparatus of dubrovnikella septfontainei n. sp. (b). d = deuteroconch, p = protoconch, om = organic membran, 1 = fi rst post-embryonic chamber. a sample os 10, b sample sl 5b/2 (see also fig. 16i). scale bars 0.2 mm. schlagintweit & velić: new and poorly known middle jurassic larger benthic foraminifera from the karst dinarides of croatia geologia croatica 93 doskeletal structures present. aperture single, basal in the early stage, later becoming cribrate with only a few large openings. most likely dimorphic. megalospheric embryonic stage complex, bilocular, consisting of a large thin-walled subglobular megalosphere and a deuteroconch enveloping the former ½ to ¾. comparisons: the characteristic features enable the inclusion of dubrovnikella n. gen. into the suborder biokovinina kaminski, defi ned as follows: “test free or attached, may be coiled in the early stage, later uncoiled or branched. wall fi nely agglutinated, traversed by pores, or with a coarsely perforate or canaliculated inner layer and an outer imperforate layer” (kaminski, 2004, p. 250). in contrast to other representatives of the biokovinidae, such as bosniella gušić and biokovina gušić, the pores in the wall of dubrovnikella are distinctly coarser; it is noteworthy that in the diagnosis of the family biokovinidae provided by loeblich & tappan (1987, p. 91) the wall is said to be “coarsely perforate”. for the superfamily biokovinacea, loeblich & tappan (1985, p. 94) characterize the wall as “fi nely agglutinated, with outer imperforate layer and coar sely perforate or canaliculated inner layer in later stage”. biokovina is unique within the biokovinids by possessing endoskeletal pillars. such elements are lacking in dubrovnikella n. gen. as well as in bosniella. both bosniella and biokovina may develop a straight uncoiled test portion, whereas in dubrovnikella only in rare specimens, a slight tendency to uncoil was observed. a third genus that has been described as belonging to the biokovinidae gušić is trochamijiella athersuch, banner & simmons, 1992 (see also kaminski, 2004, p. 250). as this genus has a test wall that “is solid and is not known to become protocanaliculate or canaliculated” (athersuch et al. 1992, p. 7) it cannot be included in the biokovinidae sensu gušić 1977 (see also loeblich & tappan, 1987). the complex embryonal apparatus consisting of a protoconch and deuteroconch or spheroconch (fig. 12b) is reported from other low er jurassic foraminifera, e.g. orbitopsella munier-chalmas, 1902 (e.g. hottinger, 1967, 2006, fig. 41h) or cym briaella fugagnoli, 1999 and middle jurassic larger benthic foraminifera, e.g. bostia bassoullet, 1998. dubrovnikella can generally be compared to some extent with lituolipora gušić & velić and cymbriaella fugagnoli. lituolipora with a more irregular coiling and a discoidal test form, has a microgranular wall “traversed by large pores that open both to exterior and interior” (loeblich & tappan, 1987, p. 91) whereas in dubrovnikella the pores are covered to the exterior by a thin imperforate layer. cymbriaella has a prominent uncoiled test portion, thick septa and an exoskeleton of beams and rafters; short beams are also present in the deuteroconch (see genus diagnosis of fugagnoli, 1999, p. 103). dubrovnikella septfontainei n. gen. n. sp. (figs. 12b, 13a–l, figs. 14a–p) origin of the name: dedicated to michel septfontaine for his numerous outstanding contributions to the knowledge of jurassic larger benthic foraminifera. holotype: slightly oblique equatorial section of a macrospheric specimen fi gured in (fig. 13c). thin section sl 2. isotypes: specimens fi gured in (fig. 13a–b, d–l, fig. 14a–m). thin sections sl 2, sl 2-1, sl 2-2, sl 2-3, sl 2-5, sl 3a, sl 3b-1, sl 3b-2, sl 4a-1, sl 4a-4, sl 5b, sl 5b-2, sz 64-3 (for abbreviations of samples see fig. 1). depository: croatian geological survey, sachsova 2, 10000 zagreb, croatia. type-locality: slano section northeast of slano village, about 25 km nw of dubrovnik (fig. 1), on the slopes of kosmatovica and kolomnić hills (fig. 4). type-level: thick-bedded, light-brownish, skeletal-bioclastic-oncoidal grainto rudstones (fig. 5; samples sl-2 to sl-5) of back-reef environment within the lower part of the stratigraphic range of gutnicella cayeuxi and in association with bosniella bassoulleti, cymbriaella lorigae, spiraloconulus perconigi, pseudocyclammina maynci, small fora mi ni fera, bioclasts of corals, echinoderms, molluscs, thau mato porellaceans etc., but before the fi rst appearance of rare timidonella sarda. diagnosis: being monotypic so far, the diagnosis is that for the genus. description: test involute, subglobular to nautiloid in form, initially planispirally later may be slightly streptospirally coiled. test usually higher than wide (height/thickness up to 1.55); thickness ranges from 0.6 mm to 1.15 mm, height 0.8 to 1.45 mm. chambers broad with crescent-shaped chamber lumina; test periphery broadly rounded. early coiling planispiral involute and biumbilicate, later with a slight tendency to be streptospiral, consisting of 1½ to 2 whorls with few chambers each (figs. 13b–c). the fi rst whorl comprises 4 to 5 chambers. during ontogeny, chambers continuously increase in size, becoming distinctly higher than long. in equ a torial section they fi rst appear rhombic later becoming more crescent-shape. an uncoiling of the last 1 to 2 chambers is rarely observable (figs. 13e–f). sutures are depressed and recurved. the megalosphere (proloculus) is globular to subglobular, mostly laterally fl attened and enclosed by a thin microcrystalline (?originally organic) membrane (fig. 12b). its inner diameter (d) ranges from 0.15 mm to 0.23 mm, most values about 0.2 mm. the height (h) of the proloculus ranges from 0.13 mm to 0.21 mm, most frequently about 0.16 mm; the d/h ratio is 1.0 to 1.54, mostly about 1.25. the proloculus is enveloped by a semi-spherical deuteroconch of reduced height. the wall is thin and fi nely agglutinating with an inner alveolar layer with simple parallel pores (diameter 0.01 to 0.02 mm) and a thin outer imperforate epidermis (thickness 0.006 to 0.015 mm). the septa are solid and not alveolar. the aperture is basal single in the early stage, later becoming cribrate with only a few broad openings. no endo skeletal structures are present. remarks and comparisons: being so far monospecifi c, see comparisons for the genus. stratigraphy: according to the foraminiferal assemblage at the type locality (fig. 4), the stratigraphic range of dubrovnikella septfontainei n. gen. n. sp. can be considered as latest aalenian-earliest bajocian. geologia croatica 64/2geologia croatica 94 figure 13: dubrovnikella septfontainei n. gen., n. sp. upper aalenian–lower bajocian of the croatian karst dinarides. a) grainstone with three specimens of dubrovnikella septfontainei and other small benthic foraminifera. b–d) equatorial sections, slightly oblique; c = holotype specimen. e) oblique section. f ) detail from e showing wall structure. g–i) oblique axial sections. note two large chamber openings in (h) and embryonic apparatus in (i) detail of which is shown in figure 12b. j–k) tangential sections of the test. l) broken equatorial section. scale bar 1 mm for a, all other pictures 0.5 mm. thin sections: a, g, j sl 2-2, b sl 2-5, c-d sl 2, e sl 3a-2, f sl 3a, h sl 4a-1, i sl 5b/2, k sl 2-3, l sl 4a-4. schlagintweit & velić: new and poorly known middle jurassic larger benthic foraminifera from the karst dinarides of croatia geologia croatica 95 figure 14: dubrovnikella septfontainei n. gen., n. sp. upper aalenian–lower bajocian of the croatian karst dinarides. a) poorly sorted packstone with dubrovnikella septfontainei n. gen., n. sp. (left) and cymbriaella lorigae fugagnoli (right). b) detail of fig. 13h showing palisade-like parallel-arranged alveoli open towards the chamber and covered by a thin outer layer of the wall (epidermis); note two large intercameral foramina (arrows). c–d) axial tangential sections; note single aperture in c (lowest chambre). e–f) equatorial sections; note cryptoendolithic thaumatoporellaceans inside the test (e). g) oblique axial section of megalospheric juvenile specimen. h) oblique section. i–j) axial sections; note broad fi nal whorl in (i). k) oblique equatorial section. l) equatorial section, most likely of a microspheric specimen. m) oblique axial section of a macrospheric specimen (detail shown in fig. 12b). n) oblique equatorial section. o–p) oblique sections. scale bar 1 mm for a, e–f, i–j, m–n, all other pictures 0.5 mm. thin sections: a, c, f sl 3b-2, b, p sl 4a-1, d, n sl 2-3, e sz 64-3, g sl 2-2, h sl 4a-4, i sl 3b-1, j sl 4b, k sl 3a-3, l sl 3b-1, m sl 5b-2, o sl 2-1. geologia croatica 64/2geologia croatica 96 suborder loftusiina kaminski & mikhalevich, 2004 superfamily loftusiacea brady, 1884 family everticyclamminidae septfontaine, 1988 genus everticyclammina redmond, 1964 everticyclammina praevirguliana fugagnoli, 2000 (figs. 15a–d) remarks: the croatian specimens of everticyclammina praevirguliana agree closely with the late sinemurian-pliens bachian material of the southern alps of italy described by fugagnoli (2000). for other liassic occurrences see bou da gher-fadel et al. (2001). in addition, e. praevirguliana was also reported (without illustration) from the sinemurian-pliensbachian of east timor (haig et al., 2007). the stratigraphic range can now be extended to include the upper aalenian–lower bajocian interval. boudagherfadel et al. (2007) introduced a mid sinemurian everticyclammina praevirguliana biozone for different sections in the mediterranean realm. stratigraphy: everticyclammina praevirguliana illustrated in this paper is of alenian age – it is accompanied by gutnicella cayeuxi, but somewhat earlier of the fi rst occurences of timidonella sarda. microfacies: intraclastic-bioclastic oncoidal and skeletal grainstone to packstone, rarely wackestone of back reef environment. everticyclammina praevirguliana is associated with rare bosniella croatica, gutnicella cayeuxi, cymbriaella lorigae, frequent small valvulinids and mostly oncolithized gastropod bioclasts. occurrences: biokovo mt. section. 4. remarks on the phylogenetic evolution of lower to middle jurassic larger benthic foraminifera the phylogenetic and morphostructural evolution of jurassic larger benthic foraminifera has been a topic of research and discussion for decades (hottinger, 1967; septfontai ne, 1980, 1988; septfontaine et al., 1991; kuznetso va et al., 1996; boudagher-fadel, 2008; kaminski et al., 2010). in 1980, septfontaine presented a use ful hierarchical grouping, starting with the outer morphology (type of coiling), presence/absence of exoskeletal and/ or endoskeletal elements and other features (mainly aperture). the temporal evolution of these elements has been the basis for phylogenetic considerations (septfontaine, 1988). with respect to the end-triassic mass extinction (e.g. tanner et al., 2004), the calculated diversity curve for agglutinated foraminifera of kaminski et al. (2010) only shows a “small dip” at the triassic/jurassic boundary. within the jurassic period, kuznetsova et al. (1996, p. 121) recognized two major evolutionary stages (megaphases): early to middle jurassic and the late jurassic to early cretaceous. concerning the appearance of “many species”, the authors recognize “obvious markers” at the base of the bathonian, the upper bathonian, the beginning of the oxfordian and at the base of the tithonian. more detailed information concerning this topic is provided by the data compilation of kaminski et al. (2010, fig. 5) showing that the origination rate of agglutinated foraminiferal genera had its phanerozoic maximum in the hettangian. this prominent peak was na med the “hettangian origination” by kaminski et al. (2010), actually covering the hettangian-pliensbachian interval and “characterized by the fi rst appearance of some larger agglutinated foraminiferal genera, derived from lituola, such as cymbriaella, haurania, orbitopsella, everticyclammina, lituosepta, biokovina etc.” considering the fi rst appearances of these genera, however, there are differing data obtainable from the literature: cymbriaella fugagnoli: so far monospecifi c cymbriaella lorigae described by fugagnoli (1999) from the domerian (= upper pliensbachian) of the southern alps, ita ly. actually we don´t know of any other record in the literature. the fi rst appearance at the base of the hettangian as indicated by boudagher-fadel (2008, p. 171 and fig. 4.6), cannot be understood. it is noteworthy that fugagnoli (2004, p. 114) again reinstated the restriction to the upper pliensbachian. our data allows the enlargement of the stratigraphic range into the lower bajocian. haurania henson: independent of the morphological intricacies (haurania vs amijiella), the fi rst hauraniids appear in the uppermost late hettangian (velić, 2007, fig. 2a). orbitopsella munier-chalmas: first appearance of the genus is in the late sinemurian (bassoullet, 1997, tab. 51; velić, 2007, fig. 7) everticyclammina redmond: the oldest representative is everticyclammina praevirguliana described by fugagnoli (2000) from the late sinemurian-pliensbachian of the southern alps, italy. as its ancestor, a species of ammobaculites was assumed. the genus everticyclammina might originate in the uppermost early sinemurian (bassoullet, 1997, tab. 51; velić, 2007, fig. 2c) or middle sinemurian according to boudagher-fadel (2008). lituosepta cati: so far monospecifi c with lituosepta recoarensis described by cati (1959) from the pliensbachian of the southern alps. according to bassoullet (1997) and velić (2007) it is known from the latest early sinemurian to the earliest lower pliensbachian . biokovina gušić: so far monospecifi c with biokovina gradacensis described by gušić (1977) from the pliensbachian of croatia. the possible total stratigraphic range extends from the uppermost late sinemurian to the lowermost late pliensbachian (bassoullet, 1997; chiocchini et al., 1994, 2008). summarizing these data, there is a more or less parallel appearance of different genera in the late sinemurian, whereas in the hettangian-lower sinemurian there is a lack of larger agglutinated benthic foraminifera. in addition to the 5 genera mentioned above, (except haurania/amijiella), lituo lipora gušić & velić also appears at the beginning of the late sinemurian (velić, 2007). these data do not show a hettangian but instead a (late) sinemurian origination event. this fi ts better with the data of other invertebrates, showing a minimum number of genera in the hettangian, the “surschlagintweit & velić: new and poorly known middle jurassic larger benthic foraminifera from the karst dinarides of croatia geologia croatica 97 ance of favourable shallow-water facies, e.g., the trento plateau in the southern alps (e.g. fugagnoli & loriga broglio, 1998) or the saharan platform (e.g. wilmsen & neuweiler, 2007). it is worth mentioning, that this extinction event in platform-dwelling larger benthic foraminifera didn´t happen exactly at the pliensbachian-toarcian boundary, but covered the whole pliensbachian (bassoullet, 1997, tab. li). biokovina and orbitopsella did not survive the intra-pliensbachian extinction as was the general assumption also for cymbriaella prior to our new data. then in the late aalenian, cymbriaella lorigae and everticyclammina praevirguliana are recorded again and the new genus dubrovnikella appeared. until now, there were no records of everticyclammina known from the late pliensbachian un til the callovian/oxfordian (fugagnoli, 2000, fig. 4). the late aalenian croatian fi ndings fi ll this gap. after the toarcian crisis, some new genera arose such as timidonella bassoullet, chabrier & fourca de, spi raloconulus alleman & schroeder, gutnicella moullade, haman & huddleston or dubrov nifigure 15: everticyclammina praevirguliana fugagnoli from the upper aalenian–lower bajocian of mount biokovo section. a–b) slightly oblique equatorial section of uncoiled specimen. c) oblique axial section. d) equatorial section. due to the size of the proloculus in b–d, these can be referred to megalospheric forms. as the uncoiled portion of the microspheric specimen should not exceed two chambers, fi gure a can also be considered megalospheric. note that the proloculus is not visible due to oblique sectioning. scale bars 1 mm. thin sections: a bst 8-2, b, d bst 8-3, c bst 8. vival phase” in the aftermath of the end-triassic mass-extinction, then increasing steadily during the sinemurian (“recovery phase”) (e.g. wilmsen & neuweiler, 2007, fig. 17; romano et al., 2008, fig. 6). for the hettangian to low er sinemurian tethyan shallow-water carbonates, assemblages of small-sized textularids and miliolids together with opportunistic taxa such as duotaxis, are recorded (e.g. boudagher-fadel & bosence, 2007), interpreted as refl ecting eutrophic conditions (fugagnoli, 2004). especially in the late sinemurian to early pliensbachian interval, larger benthic foraminifera show a progressive diversifi cation (e.g. boudagher-fadel & bosence, 2007). there is a signifi cant reduction of larger benthic foraminifera in the toarcian, following a step-by-step extinction of several species and genera during the pliensbachian (see bassoullet, 1997, tab. 51; velić, 2007, fig. 7). this extinction event can be seen in connection with a general biological crisis of other groups such as ammonoids that have been linked with the toarcian oceanic anoxic event (oae) (e.g. jenkyns, 1988; wignall & hallam, 1997; cec ca & macchioni, 2004; bilotta et al., 2010). many platforms were drowned, resulting in the disappeartable 3: dimensions of bosniella bassoulleti n. sp., upper aalenian–lower bajocian of croatia. ed = equatorial diameter (mm), dup = diameter uncoiled part (mm), ad max = maximum axial diameter (mm), ad min = minimum axial diameter at umbilical region (mm), n = number of chambers in the last whorl, ne = number of chambers in the uncoiled test portion. mean values were not calculated for those parametres with only a few data available. geologia croatica 64/2geologia croatica 98 kella n. gen. previously, the middle jurassic shallow-water carbonates of the karst dinarides were considered to be poor in benthic foraminifera. new investigations, however, have shown that these are distinctly richer in taxa than the lower jurassic strata; many of these representing index forms (velić, 2007). our new fi ndings can be considered as further evidence of this observation. acknowledgment field and laboratory investigations were supported by the croatian geological survey and the croatian ministry of science, education and sports of the republic of croatia, projects 1951953068-0241 “microfossil assemblages in carbonate deposits of the karst dinarides”, and 181-1811096-1093 “basic geological map of the republic of croatia 1:50.000”. we kindly acknowledge the helpful comments of the two reviewers ivan gušić (zagreb) and kemal tasli (mersin). a warm thank to julie robson for the english review of the paper. references altiner, d. & septfontaine, m. (1979): micropaléontologie, stra tigraphie et environment de déposition d´une série jurassique à facies de plate-forme dans la region de pinarbasi (taurus oriental, turquie).– rev. de micropal., 22, 3–18. anić, d. (1962): beiträge zur kenntnis der juraund kreideschichten des östlichen teiles des biokovo gebirges.– geol. vjesnik, 15, 161–176. athersuch, j., banner, f.t. & simmons, m.d. (1992): on trochamijiella gollesstanehi, gen., nov. et sp. nov. (foraminiferida, lof tu siacea), an index for the middle eastern marine late bathonian.– j. micropaleontol., 11/1, 7–12. bassoullet, j.-p. (1997): les grands foraminifères.– in: cariou, e. & hantzpergue, p. (coord.): biostratigraphie du jurassique ouest-européen et méditerranéen: zonations paralléles et distribution et microfossiles. bulletin des centres de recherches exploration-production elf-aquitaine mémoire, 17, 293–304. bassoullet, j.-p. (1994): bosniella fontainei nov. sp., (foraminifère, biokovinidae) du jurassique moyen de thailande.– géobios, 27, 403–411. boudagher-fadel, m.k. (2008): evolution and geological signifi cance of larger benthic foraminifera.– dev. in palaeontol. stratigraphy, 21, 1–544. boudagher-fadel, m.k., rose, e.p.f., bosence, d.w.j. & lord, a.r. (2001): lower jurassic foraminifera and calcifi ed microfl ora from gibraltar, western mediterranean.– palaeontology, 44/4, 601–621. boudagher-fadel, m.k. & bosence, d.w.j. (2007): early jurassic benthic foraminiferal diversifi cation and biozones in shallowmarine carbonates of the tethys.– senck. lethaea, 87/1, 1–39. bilotta, m., venturi, f., sassaroli, s. (2010): ammonite faunas, oae and the pliensbachian-toarcian boundary (early jurassic) in the apennines.– lethaia, 43/3, 357–380. doi: 10.1111/ j.15023931.2009.00201.x cati, f. (1959): nuovo lituolide nei calcari grigi liassici del vicentino.– giorn. di geol., 27, 1–10. cecca, f. & macchioni, f. (2004): the two early toarcian (early jurassic) extinction events in ammonoids.– lethaia, 37, 35–56. doi: 10.1080/00241160310008257 chiocchini, m., farinacci, a., mancinelli, a., molinari, v. & potetti, m. (1994): biostratigrafi a a foraminiferi, dasicladali e calpionelle delle successioni carbonatiche mesozoiche dell´appennino centrale (italia).– stud. geol. camerti, vol. spec. „biostratigrafi a dell´italia centrale”, 9–129. chiocchini, m., chiocchini, r.a., didaskalou, p. & potetti, m. (2008): ricerche micropaleontologiche e biostratigrafi che sul mesozoico della piattaforma carbonatica laziale-abruzzese (italia centrale).– mem. descr. carta geol. ital., 84, 5–170. ekmekçi, e. & altiner, d. (2008): timidonella? primitiva n. sp. (foraminiferida) from the middle jurassic of the eastern taurides (southern turkey): remarks on evolutionary steps of hauraniids.– turk. j. earth sci., 17, 73–84. fugagnoli, a. (1999): cymbriaella, a new foraminiferal genus (textulariina) from the early jurassic of the venetian prealps (northeastern italy).– rev. de micropal., 42, 99–110. fugagnoli, a. (2000): first record of everticyclammina redmond 1964 (e. praevirguliana n. sp.; foraminifera) from the early jurassic of the venetian prealps (calcari grigi, trento platform, northern italy).– j. foramin. res., 30/2, 126–134. doi: 10.2113/0300126 fugagnoli, a. (2004): trophic regimes of benthic foraminiferal assemblages in lower jurassic shallow water carbonates from northeastern italy (calcari grigi, trento platform, venetian prealps).– pa laeogeog., palaeoclimatol., palaeoecol., 205/1–2, 111–130. doi: 10.1016/j.palaeo.2003.12.004 fugagnoli, a. & loriga broglio, c. (1998): revised biostratigraphy of lower jurassic shallow water carbonates from the venetian prealps (calcari grigi, trento platform, northern italy). studi trentini sci nat – acta geol., 73 (1996), 35–73. granier, b. & deloffre, r. (1994): inventaire critique des algues dasycladales fossiles iio partie – les algues dasycladales du jurassique et du crétacé.– rev. paléobiol., 12, 19–65. gušić, i. (1969a): some new and inadequately known jurassic foraminifera from central croatia.– geol. vjesnik, 22, 55–88. gušić, i. (1969b): biostratigraphic and micropaleontologic characteristics of some jurassic cross-sections in central croatia.– geol. vjes nik, 22, 89–97. gušić, i. (1977): a new foraminiferal family, biokovinidae, from the jurassic of the dinarides and its phylogenetic relationships.– palaeontol. jugoslavica, 18, 7–31. gušić, i. & velić, i. (1978): lituolipora polymorpha n. gen., n. sp. (foraminiferida, lituolacea?) from the middle liassic of the outer dinarids in croatia and the establishment of a new family, lituoliporidae.– geol. vjesnik, 30, 73–93. haig, d.w., mccartain, e., barber, l. & backhouse, j. (2007): triassic-lower jurassic foraminiferal indices for bahamian-type carbonate-bank limestones, cablac mountain, east timor.– j. foramin. res., 37/3, 248–264. doi: 10.2113/gsjfr.37.3.248 hottinger, l. (1967): foraminifères imperforés du mesozoïque marocain.– edit. serv. geol. maroc, 1–128. hottinger, l. (2006): illustrated glossary of terms used in foraminiferal research.– carnets de géologie – notebooks on geology mem 2006/02 (cg2006_m02). jenkyns, h.c. (1988): the early toarcian (jurassic) anoxic event: stratigraphic, sedimentary and geochemicalevidence.– am. j. sci., 288, 102–151. kaminski, m.a. (2004): the year 2000 classifi cation of the agglutinated foraminifera.– in: bubík, m. & kaminski, m.a. (eds): proc. 6th int. workshop agglutinated foraminifera, grzybowski founda tion special publication, 8, 237–255. kaminski, m.a., setoyama, e. & cetean, c.g. (2010): the pha nerozoic diversity of agglutinated foraminifera: origination and extinction rates.– acta palaeontol. pol., 55/3, 529–539. doi: 10.4202/app.2009.0090 schlagintweit & velić: new and poorly known middle jurassic larger benthic foraminifera from the karst dinarides of croatia geologia croatica 99 kuznetsova, k.i., grigelis, a.a., adjamian, j., jarmakani e. hallaq, l. (1996): zonal stratigraphy and foraminifera of the tethyan jurassic (eastern mediterranean).– amsterdam, gordon and breach publ., 256 p. loeblich, a.r., jr. & tappan, h. (1985): some new and redefi ned genera and families of agglutinated foraminifera i.– j. foramin. res., 15/2, 91–104. loeblich, a.r., jr. & tappan, h. (1987): foraminiferal genera and their classifi cation.– 2 volumes (van nostrand reinhold) new york, 1–970. mikhalevich, v. (2004): on the new understanding of the order lituolida lankester, 1885 (foraminifera).– acta palaeontologica romaniae, 4, 247–267. nikler, l. & sokač, b. (1968): biostratigraphy of the jurassic of velebit (croatia).– geol. vjesnik, 21, 161–176. özkaymak, a., işintek, i̇., güngör, t. & altiner, d. (2010): foraminiferal content and age of the lower-middle jurassic homaakdağ (afyonkarahisar, sandıklı, turkey) sedimentary sequence. 63rd geol congr of turkey, 5–9 april 2010, ankara, abstracts book, 62–63. radoičić, r. (1966): microfaciès du jurassique des dinarides externes de la yougoslavie.– geologia, 9, 5–378. romano, r., masetti, d., carras, n., barattolo, f. & roghi, g. (2008): the triassic/jurassic boundary in a peritidal carbonate platform of the pelagonian domain: the mount messapion section (chalkida, greece).– riv. ital. paleontol. s., 114, 431– 452. schlagintweit, f. & velic, i. (2011): foraminiferan tests and dasycladalean thalli as cryptic microhabitats fox thaumatoporellacean algae from mesozoic (early jurassic – late cretaceous) platform carbonates.– facies. doi: 10.1007/s10347-010-0263-8 septfontaine, m. (1980): les foraminifères imperforés des milieux de plate-forme au mésozoique: détermination pratique, interprétation phylogénétique et utilisation biostratigraphique.– rev. micropal., 23, 169–203. septfontaine, m. (1988): vers une classifi cation évolutive des lituolidés (foraminifères) jurassiques en milieu de plate-forme carbonatée. rev. paléobiol., vol. spec. 2 (benthos ´86), 229–256. septfontaine, m., arnaud-vanneau, a., bassoullet, j.p., gu šić, i., ramalho, m. & velić, i. (1991): les foraminifères imperforés des plate-formes carbonatées jurassiques: état des connaissances et perspectives d’avenir.– bull. soc. vaud. sc. nat., 80/3, 255–277. tanner, l.h., lucas, s.g. & chapman, m.g. (2004): assessing the record and causes of late triassic extinctions.– earth sci. rev., 65, 103–13. velić, i. (1977): jurassic and lower cretaceus assemblage-zones in mt. velika kapela, central croatia.– acta geol., 9, 15–37. velić, i. (2005): benthic foraminifera assemblages and stratigraphic subdivision of the middle jurassic in karst dinarides, adriatic carbonate platform.– in: velić, i., vlahović, i. & biondić, r. (eds.): 3rd croatian geological congress, opatija, 2005, abstracts book, croatian geological survey, zagreb, 159–160. velić, i. (2007): stratigraphy and palaeobiogeography of mesozoic benthic foraminifera of the karst dinarides (se europe).– geol. croat., 60, 1–113. velić, i. & sokač, b. (1978): biostratigraphic analysis of the jurassic and lower cretaceous in wider region of ogulin (central croatia).– geol. vjesnik, 30, 309–337. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeogr., palaeoclimatol., palaeoecol., 220, 333–360. wignall, b. & hallam, a. (1997): mass extinctions and their aftermath.– oxford university press, 320 p. wilmsen, m. & neuweiler, f. (2007): biosedimentology of the early jurassic post-extinction carbonate depositional system, central high atlas rift basin, morocco.– sedimentology, 55, 773–807. doi: 10.1111/j.1365-3091.2007.00921.x manuscript received january 31, 2011 revised manuscript accepted march 24, 2011 available online june 09, 2011 geologia croatica 64/2geologia croatica 100 geologia croatica 45 163-172 3 fig. 2 tab. zagreb 1992 udc 551.4:04 (497.13): 519.24 sciefintic paper factor model of the geomorphological system of a part of northwestern croatia zoran peh key words: factor model, drainage basin system, re­ sistant geological framework, driving forces, geomorphic processes, geological structure, lithology the method of factor analysis (r-mode) is applied as a tool in the system approach to the investigation of a selected geomorphologi­ cal region in the northwestem croatia. the factor model derived from the analysis is a mathematical representation of the fourth-order d rain age basin system. it is composed of five orthogonal factors representing an assemblage of mutually uncorrelated subsystems as a framework within which geomorphic processes operate. lithologic variables included in the analysis prove to be an inseparable part of the investigated geomorphological system. loaded significantly on the specific factors, not only do they disclose the way the resistant geological framework opposes the activity of driving forces in the study area, but also in­ dicate most straightforwardly the connection between the geologic structure and the area! extent of the certain rock types (lithology). the former is particularly evident in the case of the sl ope factor, while the latter is characteristic for the factor of vertical dis section. l. introduction like any system-based model, the factor model reveals the essence of reality. it is a simplified and idealised representation of the natural system, emphasizing its supposedly significant features and relationships, but eliminating the incidental details (hart, 1986). the interpretation of such a model rests on the fundamen­ tal system attributes or variables, pointing at the se­ lection of the "optimal descriptors" (gardiner, 1978) as one of the crucial elements of the system analysis. as mentioned in the previous works, with the appli­ cation of the factor analysis with the purpose of treat­ ing the generated factor model as the system-based model in the geomorphological research (peh, 1990a), landforms mirror the delicate balance between driving and resistive forces. not only do they serve as regula­ tors adjusting inputs and outputs of matter and energy in the system, but they are also modificatory agents to the geomorphic processes. full attention in the geomorphological research so far has been paid mainly to the system dynamics or driving forces. the role of climate generating the exogenetic processes has been known for a long time, as well as the role of gravity participating in a number of endogenetic and exogenetic processes. however, their mutual ac­ tivity, directed to the joint surface between atmosphere ključne riječi: faktorski model, sustav erozijskih površina, rezistentni geološki okvir, aktivne sile, geomorfološki procesi, geološka struktura, litologija faktorska analiza (r-način) je primijenjena kao sistemska analiza u istraživanju odabrane geomorfološke regije u sjeverozapadnoj hrvatskoj. faktorski model dobiven analizom predstavlja matematičku predodžbu sustava erozijskih površina četvrtog reda. sastoji se od skupa međusobno neovisnih podsistema koji čine strukturni okvir za djelovanje geomorfoloških procesa. litološke varijable uključene u analizu pokazuju se kao integralni dio istraži vanog sustava. značajno opterećujući neke faktore, one otkrivaju ne samo način na koji se rezistentni geološki okvir opire djelovanju aktivnih sila, nego ukazuju i na vezu između geološke strukture i površinskog prostiranja specifičnih tipova stijena. prvi primjer očigledan je u sluča ju faktora nagiba reljefa, a drugi je karakterističan za faktor vertikalne raščlanjenosti. and lithosphere, is more or less modified by the resis­ tive force resident in the geological framework as a truly inert structural part of the geomorphological system. therefore, since landscape comes into being as the outcome ofnumerous processes wherein driving forces and resistant geology op po se each other, the set of morphometric parameters itself would not be sufficient to fully explain the dynamic nature of landscape, re­ gardless of the variety of landforms it may represent. v ario us landforms may be easily measured or described in quantitative terms, while at the same time, other ele­ ments of the geomorphological system such as rock, soil and vegetation may present considerable difficulties in quantification (za volanu, 1985). the strength of the resisting geological framework is implemented through the two essential geologic variables, lithology and structure, where the former is thought to be the dominant resistive force in the geomorphic processes. this paper presents an endeavour to include lithol­ ogy in the factor analysis and to study the evidence for the influence of some distinctive types of rocks on the structural qualities of the factor model. by comparison of two factor models, one of them containing morpho­ metric variables only and the other including the litho­ logic group of variables, one can single out the so-called lithological factors and directly point at the geologiinstitut za geološka istraživanja, sachsova 2, pp 283 cr0-41000 zagreb 164 geological processes, wherein the physical and mechanical properties of rocks play a decisive role. such an investigation logically follows the outcomes of the factor analysis applied to the study of tectonic relationships in the area amidst maceljska gora, strahinščica and ravna gora, and tends to stress more poignantly the effect of g eo logic structure on landscape development. 2. geomorphologic and geologic settings of study area the study area is situated in the northern part of hrvatsko zagorje (northwestern croatia), in a region surrounded by the mountains of ravna gora, strahinščica and maceljska gora. it lies between 46'1 o' and 46'17' north latitude, and between 15'50' and l~ east longi­ tude, in the zone of humid temperate climate (fig.1). mean annual temperature is io'c, and annual precipi­ tation averages 1000 mm, with variations depending on height (crkvenćić et al., 1974). two different orographic areas can be distinguished. closer to the borders the landscape is dominated by the mountains of low and moderate altitude, with peaks less then 1000 m. the highest peak is strahinščica (846 m), with westernmost parts of lvanščica at 727 m, ravna gora (680 m) and eastern reaches of maceljska gora (521 m). the central part of the area is characterized by low relief with a mean altitude of about 250 m. major rivers draining the area are the bednja in the east and the krapinka in the west. the major lithologic units of the study area are flg. l. map showing location of the study area slika l. karta s lokacijom područja istraživanja geologia croatica 45 summarized in fig.2, while the major structural ele­ ments are illustrated in fig.3. the structural geology is distinguished by almost linear east-west extent of individual structures that build the easternmost part of the sava folds tectonic unit (anićić & juriša, 1984,1985). several major uplifted structural blocks, represented by the horst of strahinščica, horst­ anticlinorium of ravna gora and horst-anticline of macelj, encircle the bednjamacelj depression as the single markedly subsided structure in the area. active reverse faulting on the northern flanks of raised structures stresses their asymmetrical forms. the long axis of the bednja­ macelj depression is shifted to the south, towards strahinščica, with the presence of locally overthrown strata. this relationship accommodates the regional structural scheme according to which the depth of asymmetrical depressions is always greater in the vicinity of main longitudinal faults (prelogović, 1975). the southern part of the investigated area is characterized by lateral neotectonic displacements along the system of diagonal faults striking wnw-ese. total lateral displacement of the entire system varies from 3 \0 6 kms, with maximum lateral-slip along the velenje­ rogatec fau lt zone. these movements are accompanied by rotation of minor structural blocks and thrusting of le &end: ge]o 1 ~m~2 122l m:~ fi g. 2. generalized geolog ic map of the study area (modified from aničić & jurisa, 1984 and simunić et al., 1981) slika 2. pregledna geološka karta područja istraživanja (prema aničić & jurisa, 1984 i simunić et al., 1981) legend: l) quatemaryalluvium (al) and diluvium (d); 2) t orton ian conglomerates, breccias and limestones; 3)lower miocene sandstones, tuffitic sands tone s, conglomerates, andesite tuffs, sandy and silty shales; 4) oligomiocenesands, sandstones, sandy shales and sandy maris; 5) middle t rias sicdolornites, dolomitic limestones, dolornitic breccias, shales, quartzose sandstones, tuffs, cherts, spilitized diabase; 6) lower triassic werfenian sandstones. legenda: l) kvartaraluvij (al) i diluvij (d); 2) t ortonkonglomerati, breče i vapnenci; 3) donji miocenpješčenjaci, tufitični pješčenjaci, konglomerati, andetitni tufovi, pjeskovite · i siltozne gline; 4) oligomiocen -pijesci, pješčenjaci, pjeskovite gline i pjeskoviti lapori ; 5) srednji trijas dolomiti, dolomitični vapnenci, dolomitne breče, šejli, kvarcni pješčenjaci, tufovi, čertovi, spilitizirani dijabaz; 6) donji trijas verfenski pješčenjaci. peh : factor model ... older, indurated, rocks over neo gene weakly consoli­ dated sediments (prelogović et al., 1985, an un­ published paper). the major lithologic units exposed in the area of investigation are related to the regional structural scheme. central part of the raised structures consists of pre-tertiary rocks with prevailing middle triassic carbonates (ladinian). the main lithologic types are dolomites, dolomitic breccias and dolomitic limestones (šebečić, 1970; šimunić et al., 1981,1982; aničić & juriša, 1984,1985). other lithologic types of the middle triassic are of minor importance, being represented mostly by clastic and volcaniclastic sedimentssandy shales, quartz sandstones, cherts and tuffs -and locally by spilitized dia base. lower t rias sic clastics (predominantly w erfenian sandstones) are exposed mainly in deeply eroded val­ leys in the central parts of the raised structural blocks (ravna gora). lower reaches are underlain by oligomiocene and early miocene clastic sediments (ranging from egerian to othnangian) with sporadically lege u • flg. 3. generalized structural geology map of the study area (af­ ter prelogović. 1985) slika 3. pregledna strukturno-geološka karta područja istraživanja (prema prelogović, 1985) legend: l) upright anticlinorium; 2) upright synclinorium; 3) overturned anticline; 4) fault of major importance; 5) fault of minor importance; 6) normal fault; 7) thrust fault; 8) strike-slip fault; 9), inferred fau lt; lo) major structures: l. horst of ravna gora, 2. horst of macelj, 3. horst of strahinščica, 4. bednja-macelj depresion; ll) major faults: l. fault of macelj-ravna gora, 2. fault of celje-ivanščica-nagykanizsa, 3. northern fault of strahinščica and ivanščica, 4. zone of velenje­ rogatec fault. legenda: l) uspravni antiklinorij; 2) uspravni sinklinorij; 3) prevrnula antiklinala; 4) značajniji ras jed; 5) manje značajan ras jed; 6) notmalni rasjed; 7) reversni rasjed; 8) rasjed s horizontalnim pomakom; 9) pretpostavljeni ras jed; lo) veće strukture: l. horst ravne gore, 2. horst macelja, 3. horst strahinščice, 4. bednjansko-maceljska depresija; ll) veći ras jedi: l. maceljsko-ravnogorski rasjed, 2. ras jed celje-ivanščica­ nagykanizsa, 3. sjeverni rasjed strahinščice i ivanščice, 4. ?.ona velenjsko-rogaškog rasjeda. 165 interbedded volcaniclastic rocks (bojanić et al., 1978; šikić et al., 1979). oligomiocene sands, sandy shales and sandy maris crop out in the intramountain valleys of strahinščica (the valleys of žutnica and presečina), with predominantly reverse fault-bounding to the middle triassic carbonate rock complex. the bednja-macelj depression is built of two different lithologic types of lower miocene clastic sediments. one of them is composed of coarse clastics sandstones, tuffitic sandstones and conglomerates, forming the coarse-grained facies of "macelj sandstones" formation. the other lithofacies is represented by fine clastic sediments, mainly by sandy and silty shales. the outermost southern reaches of the study area have local outcrops of tortonian sediments which, however, are not encompassed within the analyzed geomorphological system. 3. methods and materials the principles of factor analysis are well known through many examples in geology anq other sciences. therefore, there is no need for detailed discussion on the aims and purposes of factor analysis and characteristics of factor model. to understand the basics about mathematical princip les of the method, the reader should refer to the available textbooks on factor analysis (for example, fulgosi, 1984 ). its applications in geology can be found in the ever increasing number of works of the home investigators (marci & raffaelli, 1981; raffaelli & mutić, 1982; mutić, 1989; peh, 1990a,b; dra vec-braun, 1990). the foreign lit­ erature is extremely abundant and comprises almost all fields of science. since the study of geological control, particularly that of lithology, is presented here as the continuation of the previous work by the same author (peh, 1990a), some necessary details should be emphasized to clear out the scope of investigation, and the geological im­ plications of the factor ·model as well. it has already been pointed out that the resistive forces in geomor­ phology reflect themselves in the strength by which the upper part of lithosphere opposes to the activity of endogenetic and exogenetic forces. however, it is ex­ tremely difficult to allocate some numerical value to the rock hardness or its resistance to weathering (doornkamp & king, 1971). therefore, an attempt is made in this paper to express numerically the lithology of the investigated area in the form of areal variable, that is, a percentage of the total basin surface which is outcropped by a certain type of rock. definition of the rock types that would make consistent geomorphological groups according to their behaviour in geomorphic processes has been arbitrary regardless of data avail­ able from previous investigations (melton, 1957; brush, 1961; young, 1961; gregory & brown, 1966, and others). nevertheless, this can b~ justified by the fact that particular rock types (for instance sandstones) with different genesis, tectonic setting and other characteristics may similarly respond to driving 166 forces in various geomorphological regions. on the other hand, factor analysis was also conceived to serve as the test of susceptibility of the lithological variables thus defined. in the area amidst maceljska gora, strahinščica and ravna gora four rock types were specified as variables in the factor analysis. these are: l} dolomites and dolomitic limestones of the middle triassic carbon· ate pre-tertiary rocks (ca), 2) clastics and volcanics of the lower and middle triassic noncarbonate pre­ tertiary rocks (pt), 3) sandstones, tuffitic sandstones and conglomerates of the lower miocenecoarse-grained clastic sediments (kl), and 4) sandy and marly shales of the oligomiocene and lower miocenefine-grained clastic sediments (gl). morphometric variables that represent linear, areal and relief aspects of landscape do not participate in the analysis in all their diversity, but only by their most important part. most of them were described in the previous work (peh, 1990a),but, naturally, some changes were necessary with respect to the previously estab­ lished factor model. not only do they refer to the as­ sociation between lithologic and morphometric vari­ ables, but also to the introduction of several new mor­ phometric variables as the most useful optimal descriptors of the geomorphological system, particularly due to their supposed sensitivity to the variations in geology. apart from variables already used in description of the drainage network, the bifurcation ratio (kb) and confluence number (mb) are added to the analysis. as for the measures involving height and slope, the new variables describe the mean ground slope of the drainage basin (tg}, the main-valley cross-section ratio (pp), and the hypsometric integral (hi). attention should be paid to variables kb and mb, because kb is not presented as a mere arithmetical mean but the weighted bifurcation ratio taking into account the number of valleys of all orders (from first to fourth), while confluence number (mb) specifies the order of valley which the fourth­ order joins at its mouth. the potential of the variable mb lies in its possible indication of the locally raised or sunken tectonic blocks in the investigated geomor­ phological region. mathematical definition of certain variables reflecting relief aspects of drainage basins, particularly slopes, should be explained more thoroughly. mean ground slope of drainage basin (tg) is calculated according to the formula quoted by za volanu (1985) and other au­ thors, where a stands for the area of drainage basin, i.l stands for the total sum of all con tour lines of cho­ sen height interval, while .1-h represents difference in height, or the magnitude of the chosen height interval in the drainage basin, respectively. the calculated value gives the tangent of the angle of the average ground slope in the basin. ~h2:1 tanqj =--=a geologia croatica 45 the main-valley cross section (pp) is defined as the ratio between breadth (b) and height (h} of the valley in its lowest part. the breadth of a valley was measured as close to the mouth as possible, in such a way that the cross profile would not be affected by distortion of contour lines because of tributaries or any other reasons. the purpose of this variable is to reveal the tendency of a valley to cut a v -shape, or a rounded u-profile, utilizing the appropriate index, as well as to test the variable through the process of factoring. pp =b l h hypsometric integral (hl} is calculated in the way proposed by strahler (1952b), with x=a/a and y=h/ h as the elements of the percentage hypsometric curve. hl~ j~xdy the analysis comprises the total number of 24 variables, 20 morphometric and four geolog ic on es, that were assessed in 166 fourth-order drainage basins. the original matrix, having dimensions of 166 x 24, pre­ sents, therefore, the fundamental information on the geomorphological system. 4. results since the factor analysis has been used as an exploratory method, the number of the factors necessary for the interpretation of structural model was specified dur­ ing the analysis. there were not any a priori assump­ tion about the area of investigation in terms of the geomorphological system. this is true both in the case of all variables included in the analysis as in the case of only the morphometric variables taken into consid­ eration. table l represents the main factor model comprising the total of24 variables. on the other hand, table 2, containing only morphometric parameters, is added up for the reason of comparison to the main factor model. this is done with the purpose of accentuating its structural stability (as system-based model) even after the addition of lithology, and of indicating the migra­ tory tendencies (concerning factors) of some morpho­ metric variables, as well. with regard to the fact that the structural features of the factor models in tables l and 2 are not essen­ tially different from the outcomes obtained in the previous work (peh, 1990a), there is no need for detailed de­ scription of factors. similarity between the cases is logical, because the same geomorphological region has been subdued to study. certain differences could arise as the effect of increased dimensions of the study area, that is, the increased number of variables and system units (drainage basins) in respect to the earlier inv§stigation. likeness or difference in relation to different authors (for example mather & doornkamp, 1970; doornkamp & king, 1971; abrahams, 1972; onesti & miller, 1974; gardiner, 1978, and others) are mainly due to the geologic and climatic peh : factor model ... variable fl dl 0.9284* 02 0.8274* 03 0.6552* ll 0.8331* l2 0.7671* l3 0.6605* l4 0.7467* kb 0.3040 mb -0.2433 pb 0.7709* h2 0.1005 hl 0.2304 ho 0.2080 ur 0.2260 hg -0.1953 tg -0.0652 p p 0.0069 fd -0.3239 dg -0.2554 hi -0.2077 ca -0.0095 pt -0.0250 kl 0.0771 gl -0.0782 a. 5.4227 %a. 22.59 %a.cum 22.59 tab. l. varimax rotated factor matrix. tablica l. rotirana faktorska matrica. variable fl dl 0.9241 * 02 0.8947* 03 0.6120* ll 0.8075* l2 0.7849* l3 0.5515* l4 0.7500* kb 0.1622 mb -0.2253 pb 0.7014* h2 -0.0111 hl 0.1916 ho 0.1601 ur 0.2059 hg -0.0491 tg -0.0287 p p -0.0083 fd -0.1810 og -0.1046 hi -0.1377 a. 4.9o-37 %a. 24.52 %a.cum 24.52 ' factor f2 f3 -0.0565 -0.0662 -0.0623 -0.0945 -0.0331 0.1640 0.3307 -0.1047 0.2550 -0.0374 0.3143 0.1271 0.1345 -0.1185 -0.0384 0.0506 -0.0956 -0.1331 0.5467+ -0.0873 0.0137 -0.0862 0.3480 0.1121 0.7643* -0.0018 0.8315* 0.0219 0.4668+ 0.4583+ -0.0420 0.7809* 0.3722 -0.5225* -0.7573* 0.1950 -0.6935* 0.1502 -0.0249 0.5226* 0.8049* -0.0319 0.5372* 0.1302 -0.4473 0.7525* -0.1294 -0.8799 4.5724 2.9159 19.05 12.15 41.64 53.79 factor f2 f3 -0.0026 0.1287 -0.0235 0.1403 -0.0082 0.4380 0.3887 0.0375 0.3072 0.1436 0.3568 0.2484 0.1776 -0.2079 0.0120 -0.0616 -0.1125 -0.7114* 0.6022* 0.1044 0.0653 0.9228* 0.3611 0.7264* 0.8157* 0.3759 0.8680* 0.1288 0.3778 -0.0456 -0.1214 0.1824 0.4210 -0.2620 -0.8164* 0.0193 -0.7340* -0.1087 -0.1500 -0.1112 3;8960 2.5415 19.48 12.71 44.00 56.71 tab. 2. vanmax rotated factor matnx q1tholog1c vanables excluded). tablica 2. rotirana faktorska matrica (bez litololkih varijabli). 167 f4 f5 hl 0.1308 0.2190 0.9345 0.1531 -0.1632 0.7475 0.2941 -0.2711 0.6172 0.0628 0.2497 0.8807 0.1092 -0.2551 0.7319 0.1421 0.1147 0.5846 -0.1702 0.3278 0.7261 -0.0955 0.6938* 0.6870 -0.6377* 0.3955 0.6491 0.0566 0.0681 0.9087 0.8553* -0.0931 0.7680 0.7905* 0.1458 0.8329 0.4172 -0.1124 0.8142 0.1922 -0.0781 0.7859 0.2038 0.2445 0.5674 0.1839 -0.0332 0.6507 -0.2937 -0.2595 0.5652 0.1408 0.0771 0.7422 0.0710 0.2447 0.6337 -0.0156 0.3673 0.4520 0.0954 0.1740 0.6883 0.4639 0.2613 0.5896 -0.2290 -0.1999 0.9647 0.0772 0.0523 0.8057 ·2.6479 1.5574 11.03 6.49 64.82 71.31 f4 f5 hl -0.0551 0.2535 0.9378 -0.1064 -0.2197 0.8803 -0.0070 -0.0593 0.5701 -0.0303 0.2622 0.8742 -0.0670 -0.2329 0.7898 0.0710 0.3657 0.6320 -0.0905 0.2735 0.7204 0.0445 0.8863* 0.8178 -0.0834 0.2825 0.6563 -0.0876 0.1813 0.9060 -0.1105 0.0940 0.8769 0.2487 0.1042 0.7675 0.1518 -0.0785 0.8614 0.1930 -0.0922 0.8581 0.7685* -0.1768 0.7690 0.7404* -0.0409 0.6121 -0.5331 -0.2773 0.6071 0.2798 -0.1457 0.7991 0.3115 -0.0467 0.6607 0.6111* 0.1451 0.4483 2.1691 ·1-.534-510.85 7.67 67.56 75.23 168 characteristics of the studied areas, as well as to the different choice of the relevant morphometric and g eo logic properties that describe the respective geomorphological systems. with this on mind, the importance of lithol­ ogy which, as comes to be clear from the close inspection into the tables enclosed, does not leave mark on all factors (or geomorphological processes they represent), tends to be still greater. the main factor model (table l) is composed of five factors, namely the factor of horizontal dissection fl, the factor of vertical dissection f2, the factor of slope f3, the factor of erosionallevels f4 and the factor of the bifurcation ratio f5. their functional characteris­ tics are discussed in the next section. s. discussion assuming that factor analysis enables an open system to be defined by mathematical criteria, the factor model is a mathematical expression of the inherent structure of such a system, with individual factors directly or indirectly indicating certain processes characteristic to its internal dynamics. the question remains to be answered as to how much the common factors, defined in such a way, represent all the active and passive participants in the landscape development. the answer is far from being straightforward. although factors mirror genetic relationships among individual variables, it is extremely difficult to identify them with some specific geomorphic process. for example, in reference to the slope factor f3, it is undetermined if it can explain the influenr" of all those variables controlling the behaviour of val­ ley slope, valley-side slope, ground slope or hypsometric integral. explanation of the factor variability may be additionally burdened by the high factor loading of the same variable on more than one factor, as in the case of variable pb (fl-f2), and 1:0 the somewhat lower degree in the case of variable hg (f3-f4). geomorphic processes that lead to the appearance of various landforms originate in the action of oppos­ ing forces operative on the surface of the earth. they are seen as the result of the mutual work of driving forces that provide energy, and the resistant geological framework which counteractsthe former by the strength of its physiographic constitution (ritter, 1978; hart, 1986). from this point of view, the form and process relationship does not depend only on the amount of energy applied, but also on the properties of materials being worked on by the driving forces. lithology and struc­ ture exert considerable influences on the transfer of mass · and energy through the system, regardless of wheather the main driving forces are endogenetic or exogenetic in nature. furthermore, there is a tendency of estab­ lishing a delicate balance between form and process, a kind of very subtle equilibrium which is inanifested through significant statistical correlations among the system variables (strahler, 1956; hack, 1957; chorley, 1962; howard, 1965; chorley & kennedy, 1971; pozdnjakov, 1988 and others). geologia croatica 45 such a close association between form and process offers a possibility that careful examination of relationships among the variety of landforms, as well as the geological features of the area, may lead to the recognition of the processes which created them, provided that the mechanism of resistance to the operative forces is known. if the assumption is accepted that the factor model represents a mathematical expression of the system in balance, with factors forming an assemblage of geo­ morphic processes in some kind of "statistical equi­ librium" with various landforms, then it may prove possible to reveal the evidence of geologic control in certain factors. here it must be emphasized that according to the accepted opinions, the bedrock lithology is probably the most important resistive component ·in the process of landscape development (za volanu, 1985). 5.1 lithology various rock types, because of their resistance to weathering, differently affect the behaviour of certain morphometric variables such as the ground slope (melton,l957;young, 196l;gregory &brown, 1966, and others), drainage density (horton, 1945; carlston, 1963 and others) and longitudinal valley profile (hack, 1957; brush, 1961 and others) among other. rock resistance to erosion is .defined by its physi­ cal and mechanical properties. according to prevailing opinion, porosity and permeability, which directly af­ fect the relationship 9etween overland flow and infil­ tration, are the most important physical properties of rocks. drainage density is probably the most sensitive morphometric parameter which reacts to them. on the other hand, strength, hardness and resistance to weathering appear to be the most prominent mechanical proper­ ties (za volanu, 1985), and slope variables are most susceptible to their variations. before broaching the subject of how lithology loads on individual factors, it is necessary to explain the meaning of the sign the lithologic variables bear in the correla­ tive relationships with other variables. lithologic variables as presented in this work do not reflect some physical or mechanical rock property in the form of a numeri­ cal parameter, but simply the relative presence of a certain rock type in a drainage basin as a whole. that is why the sign of a particular lithologic variable in the fac­ tor model does not define the character of its associa­ tion with morphometric variables explicitly, which is the question when their loadings on the same factor are charged oppositely. this can be interpreted in two ways. if the loading of a specific lithological variable is negative, while at the same time, the loading of the morphomet­ ric variable representing, for example, the highest point on divide ho is positive on the same factor, it may reveal the scarce appearance of the respective rock type in the area of high relief. however, this association can also be expressed inversely, as ah abundant occurrence of the same rock type in the area of low relief. the sign .peh : factor model ... of factor loading has no intrinsic significance in itself with no information on dependency between variable and the factor (kim & mueller, 1978). that is why both way of reasoning can be utilized to present the outcome of the analysis. two lithologic factors are revealed in the factor model. lithologic variables are strongly built in the frame of the f2 and f3 factors, suggesting that rock type con­ trols the behaviour of morphometric variables such as drainage density or ground slope. although its influence on process has been recog­ nized, lithology is often thought to be a more or less passive or static participant in landscape development. on that assumption, the factor model resulting from the factoring of the same set of data should not be essentially different if the lithologic variables were removed. in other words, fundamental re'lationships among the morphometric variables would not be affected by the presence or absence of lithologic variables (at least regarding the way they are defined in this work). the comparison between tables l and 2 shows that after the lithologic variables ca, pt, kl and gl had been re­ moved, the inner structure oftlie system remained without substantial alterations. this, of course, implies the strong effect of other, "active" variables in geomorphic pro­ cesses leading to a particular landform assemblage. re location of f3 and f4 factors by this procedure does not play an important role in the hierarchy of factors. it is more important to point out the communalities of some morphometric parameters, especially of the variables kb and hg. lithologic variables once been removed, the communalities of kb and hg considerably increase. kb enlarges its communality by 28.2%, and hg by 26.2%, which means that rock type imposes some additional constraints on the relationships among the system components. practically, it means thatiflithology is excluded, the variable hg firmly takes its place on the slope factor, while the dominance of variable kb on the f5 factor becomes still greater. likewise, there is an -increase in the communality of variables d2 · (+l~i.l%) and h2 (+12.4%) which indicates lithology imposes additional constrictions in their behaviour as well. fl is completely free from any lithologic control (as is shown on table 1). being considered as the size factor (doornkamp & king, 1971) it simply points to the fact of linear basin elements developing within the area available. but the total number and length of valley s of various orders, as well as the area of drainage basin, do not react to differences in lithology among sandstones, shales and dolomites. some authors have indicated that a relationship exists between various rock types and average area needed for drainage basin de­ velopment (za vo ianu, 1985), although physiographic properties of rocks seem to influence the development of drainage.network primarily by variables which control drainage density d.g (and fd). · ·. f2 is heavily loaded by lithologic variables.· the fact 169 that its character is virtually unaffected by removing the lithologic variables (tables l and 2), except that loadings on the key morphometric variables become still heavier, leads to the conclusion that they are more or less inertly loaded on the factor. the high positive loading on the group ca-pt mirrors most straightfor­ wardly the geologic setting of the study area, since triassic dolomites and, to the somewhat lower degree, trias­ sic clastics and volcani cs occur in the hearts of the re­ gional mountains of strahinščica and ravna gora. the bednja-macelj depression, which is built of lower miocene sandstones and shales, is characterized by low relief. this latter relationship is partly mirrored in the factor model by the significant loading on the variable kl with negative sign ( -0.45). no strong er relationship is established between the relief aspects and the occurrence of weakly consolidated lower miocene and oligomiocene sediments gl (-0.13). drainage density is one of the most significant component parts of the landscape assemblage, and terrain transmissibility, depending on the bedrock and soil permeability, occurs as a dominant factor that controls it (carlston, 1963). since the terrain transmissi­ bility and drainage density vary inversely to each other (horton, 1945; carlston, 1963),the highly permeable areas will not stimulate development of dense drainage network. at the same time, low drainage density will be conditioned by high bedrock resistance to weathering (strahler, 1952a). triassic dolomites (ca) in the study area are distinguished by their very high degree of fracturing, and, at some places (particularly on ravna gora), with well developed karst landforms, so that this variable qui te nearly fits in f2 factor, where the relationship between drainage density and occur­ rence of dolomite rocks are inversely proportional. proportional relationship between drainage density and occurrence of lower mi ocene sandstones may be the reflection of their low transmissibility. this statement is also supported by the evidence of sandstones abounding in perennial and ephemeral streams, which indicates that most of the precipitation, less amount of evapo­ transpiration, ends in surface runoff. f3 reveals the lithological control most conspicu­ ously. the fact that lithologic variables cause the re­ location of the slope factor in the hierarchy of factor significance (amount of information contained), as well as the fluctuating status of important morphometric variable hg (similar loading s on both f2 and f3) speaks on behalf of significant lithologic control. the most important feature of f3 is the inversely proportional relationship between the variables kl and gl; both have heavy loadings, except that their behaviour is entirely different relative to the set of morphometric variables involving the slope aspects of landscape. positive correlation of variable kl with the slope characteris­ tics indicatcs that sandstone areas are distinguished by steep ground slope, steep fourth-order valley slopes, v -shaped fourth-order valley s and high hypsometric 170 integral. on the contrary, negative correlation of the variable gl with the slope characteristics reveals that areas occupied by lower miocene shales are dominated by gentle slopes, u-shaped valleys and low hypsometric integral. at the same time, very low factor loading on the ca-pt group of variables shows that the slope is not essentially influenced by the physiographic prop­ erties of triassic rocks. the slope characteristics in the area of strahinščica and ravna gora are probably under control of other variables. the relationship between the morphometric and lithologic variables loaded on the slope factor f3 supports the general conclusion about the behaviour of some rock types in the process of landscape development. in this case, the most prominent trait appears to be the difference between sandstones and shales, because they have direct impact on the slope parameters. relationship resulting from the analysis is in accordance with the opinions of many authors that sandstones are more resistant to erosion than shales in the temperate climate zones (brush,1961). sandstones possess sufficient internal strength in respect to shales to permit steeper characteristic and maximal slope angles. this is reflected in more pointed landforms ( + tg) and characteristic v-shaped valley transverse profite (-pp) in the portion of the bednja-macelj depression underlain by sandstones. the main valley slope (hg) is also steeper in sandstones, but the double entity of this variable (0.4 7f2+0.46f3) points to a conclusion that valleys with high values of slope are typical of triassic carbonate rocks a8 well. finally, the hypsometric integral as a rather spec if; · morphometric variable also indicates greater resistance of sandstones with regard to shales. an interesting feature of this variable is its directly proportional relationship to the other slope parameters in the area of heteroge­ neous lithology. this relationship can result from some other variables operative in the area, particularly from vertical neotectonic movements which tend to rejuve­ nate the landscape and create (through reinforcement of erosion processes in the valleys) steeper relief, re­ gardless of lithology. a brief inspection into the factor matrix (table l) can affirm that erosional levels (loaded on f4) and bifwcation ratio ooaded on f5) are not in the least affected by the variations in lithology. significant loading on f4 with the variable pt can be explained by the strong influence of a single object, an outlier, in the set of original data. it is the case of the valley of kamenica in the heart of ravna gora, which is distinguished by exceptiomillyliigh erosionallevels (h2=297m, h1=488m). middle triassic dolomites have been removed by erosion, so that the kamenica presently has been cutting its way into lower triassic clastics. 6. conclusions factor analysis proves to be a valuable method in the exploration of geomorphological systems, largely due geologia croatica 45 to its basic feature of being a multivariate technique allowing insight into simultaneous relationships among system elements. the analysis has been applied to a selected geomorphological region wherein the system has been defined by the set of fourth-order drainage basins as the fundamental system units. factoring of the original set of data (r-mode factor analysis) resulted in a factor model which can be defined as a geomor­ phological system-oriented model (hart, 1986). to a certain degree, that model simplifies the complex relationships in the geomoiphological system and permits a look into the basic structure of data. a factor model is composed of five orthogonal factors which implicitly disclose processes operatfng in the general scheme of landscape development it is an arduous task to associate each of the concerned factors with a specific geomorphic process (or processes), but still it can be said without doubt that the main reason for individual system variables grouping or loading on a certain factor lies in their high mutual correlations originated in the activity of driving forces upon a re­ sistant geological framework. a factor in a mathematical sense represents a latent variable (fulgosi, 1984) the character and significance of which depend on entanglement of interrelations of original or manifestable variables. the process, again, represents a unifying variable (ritter, 1978), which ties together active forces providing energy (tectonics, climate) and passive geology (lithology, texture) in their mutual creation of surface features of the earth. thus, connection between ~e factor and proces s, although not explicitly shown: becomes .obvious. the most striking characteristic of the factor model is its susceptibility to the variations in bedrock geol­ ogy. strong geologic control is present in the factors of vertical dissection f2 and slope f3. while the fac­ tor of vertical dissection seem s to reveal the dominant control of the structural setting of the triassic carbonate complex underlying the most uplifted parts of the regional mountains, the slope factor points at a causal relation­ ship between physiographic properties of lower mio­ cene and oligomiocene sediments on one hand, and slope aspects on the other. the main factor model reveals this profound relationship in both cases by the very high factor loadings of lithological variables. carbonate and clastic pre-tertiary rocks (ca, pt) come into promi­ nence in the case of the factor of vertical dissection, while coarse-grained and fine-grained clastics of the oligomiocene and lower miocene characterize the slope factor. 7. references abrahams, a.d. (1972): factor analysis of drain­ age basin properties: evidence for stream ab­ straction accompanying the degradation of re­ lief. water resour. res., 8, 624-633. aničić, b. & jurisa, m. (1984 ): osnovna geološka karta sfrj, 1:100 ooo,listrogatec, l 33-68. peh : factor model o oo geološki zavod, ljubljana i geološki zavod, za­ greb, 1983, savezni geološki zavod, beograd. anićić, b. & juriša, m. (1985): osnovna geološka karta sfrj 1:100 000, tumač za list rogatec, l 33-68. geološki zavod, ljubljana i geološki zavod, zagreb, 1973, savezni geološki zavod, 76 str., beograd. bojanić, a., tišuar,j. &majer, v. (1978): klastični miocenski sedimenti sjeverozapadnog dijela maceljske gore (hrvatska, jugoslavija). geol. vjesnik, 30/2, 445-452, zagreb. brush, m.ljr. (1961): drainage basinchannelsandflow characteristics of selected streams in central pennsylvania.u.s. geol. survey prof. paper, 282-f, 145-180. carlston, c.w. (1963): drainage density and streamflow.u.s. geol. geol. survey prof. pa­ per, 422-c, 8 p. chorley, r.j. (1962): geomorphology and general systems theory.u.s. geol. survey prof. paper, 500-b, 10 p. chorley, r.j. & kennedy, b.a. (1971): physical geography: a systems approach.prentice-hall international inc., 370 p., london. crkvenćić, i., friganović, m, pavić, r.,rooić, v. & sić, m. (1974): geografija sr hrvatske: središnja hrvatska (knjiga 2).školska knjiga, 575 str., zagreb. dra vec-braun, j. (1990): primjena faktorske analize u statističkoj obradi podataka geokemijske prospekcije na papuku i kmdiji. geol. vjesnik, 43, 159-168, zagreb. doornkamp, j.c. & king, c.a.m. (1971): numerical analysis in geomorphology. -edward arnold, london, 368 p. fulgosi, a. (1984): faktorskaanaliza.školska knjiga, 368 str., zagreb. gardiner, v. (1978): redundancy and spatial orga­ nization of basin form indices: an empirical in­ vestigation of data from north-west devon. -trans. inst. br. geogr., 57,417-431. gregory, kj. & brown, e . .h. (1966): data processing and and the study ofland form.zeit furgeanorph., 10, 237-263. gregory, kj. & w alling, d.e. (1973): drainage basin form and process. -edward arnold, london, 450p. hack, j. t. (1957): studies oflongitudinal stream profiles in virginia and maryland.u.s. geol. survey prof. paper, 29~b. hart, m. g. (1986): geomorphology pure and applied. george allen and unwin, london, 213 p. horton,r.e.(l945):erosionaldevelopmentofstreams and their drainage basins: hydrophysical approach to quantitative morphology. geol. soc. am. bull., 56, 275-370. how ard, a.d. (1965): geomorphological systems 171 equilibrium and dynamics. -am. jour. sci., 263, 302-312. . kim, j.o. & mueller, c.w. (1978): factor analy­ sis: statistical methods and practical issues. in: enjukov, i.s. (ed.): faktornij, diskriminantnij i klasternij analiz. finansi i statistika, moskva 5-77 (russian translation). marci, v. & raffaelli, p. (1981): kemijske karakteristike amfibolskih stijena sjeverozapadnog dijela psunja: razlikovanje ortoi paravarijeteta. geol. vjesnik, 33, 133-144, zagreb. ma ther, p.m. & ooornkamp, j.c. (1970): multi­ variate analysis in geography with particular reference to drainage basin morphology. -trans. inst. br. geogr., 51, 163-187. melton, m.a. (1957): an analysis of the relations among elements of climate, surface properties and geo­ morphology. -columbia univ., dept. geol., of­ fice ofnaval research, project nr 389-402, 102 p. mutić, r. (1989): korelacija kvartara istočne slavonije na osnovi podataka mineraloško-petrografskih analiza (istočna hrvatska, jugoslavija), dio i. dravska potolina. -acta geol. 19/1, (prir. istraž. 59), jugoslav. akad. znan. umjeto., 1-60, zagreb. onesn u. & miller, t .k. (1974): patterns of variatioo in a fluvial system.wal resour. res., 10, 11781186. peh, z. (1990a): application of factor analysis in dynamic geomorphology.geol. vjesnik, 43, 59-67, zagreb. peh, z. (1990b): način izrade i primjena faktorskih karata u analizi strukturnih odnosageol. vjesnik, 43, 69-79. zagreb. pozdnjakov, a. v. (1988): dinamičeskoe ravnovesie reljefoobrazovanii. nauka, 207 str., moskva. prelooović,e.(1975):neotektonskakartasr~e. geol. vjesnik, 28, 97-108, zagreb. raffaelli, p. & mutić,. r. (1982): mogućnost razdvajanja teških minerala.metodom faktorske analize. zbornik radova, ~-.;jubilarnog kongresa geologa jugoslavije, knjiga i, 495-508, budva. ritter, d.f. (1978): process geomorphology.wm. c. brown, 593 p., dubuque, iowa. strahler, a.n. (1952a): dynamic basis of geomor­ . phology.geol. soc. am. ,bull., 63,923-938. strahler, a.n. (1952b): hypsometric (area-altitude) analysis of erosional topography. geol. soc. am. bull., 63, 1117-1142. strahler, an. (1956): equilibrium theory of erosional slopes approached by frequency dislribution analysis. -am. j. sci., 248, 673-696; 800-814. šebećić, b. (1970): sedimentne stijene strahinščice. geol. vjesnik, 21, 241-256, zagreb. . šikić, l., šimunić, an. & šikić, k. (1979): neogen in central and northern croatia. in: drobne, k. (ed.): 16th europian micropaleontological colloquium, 123-130, ljubljana. šimunić, an., pikda, m. & hećimović, l. (1982): 172 osnovna geološka karta sfrj, 1:100 000, list varaždin, l 33-69. geološki zavod, zagreb, 1979, savezni geološki zavod, beograd. šimunić, an.,pikua, m. & hećimović, i. (1981): osnovna geološka karta sfrj, 1:100 000, tumač za list varaždin, l 33-69. geološki zavod, geologia croatica 45 zagreb,l979, savezni geološki zavod, 75 str., beograd. young, a. (1961 ): characteristic and limiting slope angles. -zeit. fur geomorph., 5, 126-131. za volanu, 1., (1985): morphometry ofdrainage basins. elsevier, 233 p., amsterd~. faktorski model geomorfološkog sustava dijela sjeverozapadne hrvatske z. peh faktorska analiza se pokazuje vrlo značajnom u istraživanju geomorfoloških sustava budući da kao multivarijantna matematska metoda pruža uvid u simultane odnose među njihovim elementima. analizom je obrađena odabrana geomorfološka regija u kojoj je sustav definiran kao skup erozijskih površina četvrtog reda s ulogom osnovnih sistemskih jedinica. faktorizacijom izvornih podataka (r-način) stvoren je faktorski model koji se može definirati kao geomorfološki, sistemski orijentirani model (hart, 1986). do stanovite mjere takav model pojednostavnjuje složene odnose u geomorfološkom sustavu, ali istovremeno otkriva i osnovnu strukturu morfometrijskih podatka. faktorski model se sastoji od pet ortogonalnih faktora koji implicitno ukazuju na procese oblikovanja reljefa. vrlo je teško povezati svaki od promatranih faktora s nekim određenim geološkim procesom (ili procesima), ali se sa sigurnošću može reći da je uzrok grupiranja sistemskih varijabli na pojedinim faktorima skriven u visokim međusobnim korelacijama koje nastaju u procesu djelovanja aktivnih sila na rezistentni geološki okvir. faktor se u matematskom smislu može smatrati latentnom varijablom čiji karakter i značenje ovise o spletu međusobnih odnosa izvornih ili manifestnih varijabli (fulgosi, 1984). proces, pak, predstavlja unificirajuću varijablu koja povezuje aktivne sile (energija) i pasivni geološki okvir (rezistentna masa uobličena u litološkim i strukturnim značajkama promatrant! geomorfološke regije) u zajedničkom stvaranju reljefa (ritter, 1978). veza između faktora i procesa postaje tako očigledna. najbitnijom značajkom faktorskog modela pokazala se njegova osjetljivost na varijabilnost geološke podloge. jak utjecaj geoloških činitelja prisutan je u faktorima vertikalne raščlanjenosti f2 i nagiba reljefa f3. međutim, dok faktor vertikalne raščlanjenosti ipak u prvi plan ističe dominantan utjecaj strukturnog smještaja trijaskog karbonatnog kompleksa, koji tvori jezgru najviše izdignu tih dijelova regionalnih struktura, faktor nagiba ukazuje na uzročno-posljedično vezu između fiziografskih osobina oligomiocenskih i donjomiocenskih sedimenata s jedne i nagiba reljefa s druge strane. u oba slučaja se glavni faktorski model (tablica l) odlikuje visokim faktorskim opterećenjima litoloških varijabli. karbonatne i klastične predtercijame stijene (ca, pt) karakteriziraju faktor vertikalne raščlanjenosti, dok krupnozrnasti i sitnozmasti klastiti oligomiocena i donjeg miocena (kl, gl) opterećuju faktor nagiba reljefa. manuscript received march, 31.1992. revised manuscript accepted june, 10.1992. '·· 09-zupanic.indd � ab stra ct mt. promina became famous for its coal mines, vertebrate remains and fossil fl ora, and for the use of its name in denoting sediments covering a wide area of the dinaric coastal range. the promina beds of the type area, mt. promina, are up to 1 km thick and evolved in the context of propagating dinaric deformation towards the foreland. they consist of eight sedimentary units differing in facies, i.e. depositional environments and systems, which include alluvial, lacustrine, deltaic, lagoonal and shelf deposits. the sedimentary units constitute three depositional cycles. cycle i is represented by a late lowstand alluvium, while cycles ii and iii consist of transgressive and highstand (regressive) systems tracts. cycle iii also includes a coastal onlap of limestones and an alluvial onlap. transgressive tracts are specifi c in being represented by lacustrine deposits and having non-erosive bases. falling-stage sediments have not been identifi ed. the promina beds of mt. promina represent an example of sedimentary and sequence evolution at a foreland basin margin. the evolution of this margin is characterised by structural and stratigraphic complexities including syndepositional folding, growth strata, angular unconformities, intraformational faulting, alluvial and marine onlaps onto deformed basement, and tectonically induced, proximal-distal variations in facies and sediment thickness. the origin of lacustrine transgressive tracts may have been related to backtilting in the proximal part of the basin. high sediment supply and subsidence pulses are proposed to have been the two main factors which shaped the depositional styles, sequence development and distribution of sediments. the dominant role of tectonism in the sedimentary evolution was related to the position of the area within deforming; marginal parts of the foreland basin, situated in close vicinity to the main, active dinaric thrust units. keywords: foreland basin, sedimentary cycles, sequence stratigraphy, synsedimentary tectonics, dinarides sedimentary evolution of an inner foreland basin margin: palaeogene promina beds of the type area, mt. promina (dinarides, croatia) � jožica zupanič1 and ljubomir babić2 1institute of mineralogy and petrography, department of geology, faculty of science, university of zagreb, horvatovac 95, 10000 zagreb, croatia 2institute of geology and paleontology, department of geology, faculty of science, university of zagreb, horvatovac 102a, 10000 zagreb, croatia; (ljubomir.babic@zg.htnet.hr) doi: 104154/gc.2011.09 geologia croatica 64/2 101–119 28 figs. zagreb 2011 geologia croaticageologia croatica 1. introduction during the late stage evolution of foreland basins, usually called the molasse stage, sedimentation rates outpace subsidence rates, and deposition occurs in shallow-marine and continental settings (e.g. flemings & jordan, 1989; allen et al., 1991; crampton & allen, 1995). at the same time, the basin, especially its orogen side, commonly experiences deformation which provokes specifi c structural and stratigraphic complications (review in miall, 1978). this study deals with the promina beds (pb), which are regarded as representing palaeogene molasse deposits of the di naric orogen (e.g. marinčić, 1981). the focus is on suc cessions up to 1 km thick, exposed on mt. promina (mtp), geologia croatica 64/2geologia croatica 102 the type area of the pb (figs. 1−3). the fi rst purpose of this contribution is to provide basic data on various shallow-marine, deltaic, lacustrine, and alluvial facies, their vertical pattern and lateral variability, as well as their arrangement in eight distinct sedimentary units. using these data, the successions of these units are shown to refl ect specifi c changes in the relationship between accommodation and sediment supply, which defi ne depositional cycles based on sequence stratigraphic concepts (posamantier & vail, 1988; po samentier & allen, 1999; embry, 2002; catuneanu, 2006). later the development of complex relationships between sedimentary, stratigraphic and structural features characterising the type area of the pb are described. the question of dominant factors controlling the sedimentary evolution and sequence development of the studied basin are also addressed. while some authors proposed a variation in subsidence rates related to tectonic loading (hel ler et al., 1988), other workers suggested that eustasy generates progradational to aggradational cycles in the proximal part of the foreland basin, where the subsidence always exceeds the eustatic falls (posamantier & allen, 1993). variation in sediment supply coupled directly with tectonic loading is the third principal factor suggested to dominantly infl uence the origin of transgressive-regressive sequences in a foreland basin (lopez-blanco et al., 2000; marzo & steel, 2000). the complex history of the type area of the pb is discussed in the context of its specifi c, marginal position in the foreland basin, which was strongly infl uenced by tectonism. 2. geological setting and study area the pb is situated in the outer part of the dinaric orogen, in the imbricate-folded belt, which roughly corresponds to the dinaric coastal range (figs. 1, 2). this belt consists of cretaceous to eocene platform carbonates, eocene-oligocene foreland basin clastics, and minor neogene and quaternary deposits (e.g. mamužić, 1975; ivanović et al., 1978). on its inner side, it is bounded by larger dinaric thrust units. along its adriatic side, it is bounded by the foreland, which is a common to both the dinarides and the apennines (fig. 1). for most of the mesozoic to eocene period, the area of the imbricate-folded belt was part of the carbonate platforms, which characterised a major part of the future outer dinarides (vlahović et al., 2005; korbar, 2009). the swdirected (present-day orientation) propagation of tectonic de for mation of the dinaric orogen, and related migration of foreland basins, led to basin formation in the area of the present-day imbricate-folded belt during the middle eocene (e.g. ivanović et al., 1977; mamužić, 1975). the basin was fi lled by deep-water clastics known as the eocene fl ysch (e.g. marinčić, 1981; babić & zupanič, 2008), and by more than 2 km of middle eocene-early oligocene pb (ivanović et al., 1978; mamužić, 1975; sakač et al., 1993) regarded as representing a molasse (chorowicz, 1977; herak & bahun, 1979; marinčić, 1981). it is possible that the promina basin was carried piggyback (babić et al., 1995) on a huge, complex nappe (korbar, 2009). parts of the pb originated in alluvial, coastal, deltaic, and shelf settings, and the successions of pb display a cyclic arrangement of sedimentary units related to the fl uctuation of relative sea-level (zupanič, 1969; babić & zupanič, 2007 with ref.; mrinjek, 2008). two main “orogenic phases” have been cited for the area: before the pb, in the middle eocene, and after the pb, in the oligocene-miocene (ivanović et al., 1978). the recently proposed miocene age of the coastal fl ysch, and a younger age for fan deltaic and alluvial deposits of the pb (mikes et al., 2008), challenged previous, palaeogene dating, and requires caution and additional confi rmation. the study area coincides with the type area of the pb in mt. promina (mtp) (fig. 3). this area became famous for its coal mines, vertebrate remains, fossil fl ora (reviews in kerner, 1901, and marković, 2002), as well as for a debate on the location of an unconformity which would be related to the main deformation of the coastal dinarides (sakač et al., 1993 with ref.). several papers have described the sucfigure 1: location of the promina basin within the adriatic coastal range and dinaric orogen. framed area is shown in fig. 2. figure 2: location of the promina basin (dark grey) within the imbricatefolded belt (light grey), which is bounded by important thrust faults: v, velebit-knin-mosor thrust to ne, and tv, trieste-vis fault zone to sw. simplifi ed after prelogović et al. (2003; with references). framed area is shown in fig. 3. zupanič and babić: sedimentary evolution of an inner foreland basin margin: palaeogene promina beds of the type area, mt. promina... geologia croatica 103 cessions of pb in mtp (fig. 4). however, knowledge on the sedimentary and basin evolution of this critical area for the evolution of the dinaric orogen has remained fragmentary. this also applies to the dating of the sediments for which the age has loosely been defi ned as spanning the late middle eocene to early oligocene (kühn, 1946; sakač et al., 1993). since the 19th century, the promina name has also been used for much thicker successions exposed in a considerably larger area (fig. 2). however, a correlation along the promina basin has shown that the mtp area contains the upper part of the entire pb (babić & zupanič, 2007). this is related to an overall, ne trending onlap of pb (quitzow, 1941), and the location of mtp in the ne, marginal part of the basin. a previous study of the pb, which covered only parts of mtp, reported on an alluvial unit, lacustrine unit, and shelf/delta cycles, which were compared to lowstand, transgressive, and highstand systems tracts, respectively (fig. 4). the work presented here includes the entire succession, from the basal unconformity to the youngest strata on the mountain top. it is based on the study of a considerably larger area of the mountain, and takes into account important lateral changes reported by zupanič (1969). 3. methods mtp displays well exposed individual segments of sedimentary successions at different locations, while more continuously exposed sections are uncommon. this hampered the figure 3: outline geology of mtp and its vicinity. simplifi ed after ivanović et al. (1977). age of pb after kühn (1946) and sakač et al. (1993). thick, dashed line delineates the study area presented in fig. 5. figure 4: current and earlier subdivisions of upper pb (simplifi ed). 1, mtp: reconstructed from kerner’s data (1894, 1986). 2, mtp: from zupanič (1969); t-r, transgressive-regressive cycles start with marine strata and end with either lagoonal, swamp, deltaic, or alluvial deposits. 3, largest part of the promina basin: compiled from babić & zupanič (1990, 2007), zupanič et al. (1988), and babić et al. (1995). 4, mtp: after babić & zupanič (2007). 5, mtp, this work. logs from mtp refer to its main, southern part. lst, tst and hst are lowstand, transgressive and highstand (regressive) systems tracts, respectively. small marks in the upper hst of logs 3 and 5 symbolise subcycles (schematically). for details see text. work, especially in fi ner grained rocks and in transitions between sedimentary units, as well as for correlation. this was partly overcome by mapping at a scale of 1/25000 and locally at 1/5000 scale, and by studying rather closely located sections. twelve logs have been measured at 1:100, and 1:50 scales. field data were complemented by the study of more than 200 thin-sections. 4. gross compositional data most of the studied clastics commonly contain lithoclasts which are almost exclusively carbonate in composition, with a high dominance of cretaceous and middle eocene limestone clasts. there are exceptions which are specifi ed at appropriate places in the text. 5. description and interpretation of sedimentary units this section presents the basic data on the facies of sedimentary units and the main aspects of their depositional environments and systems. the units have been separated based on sharp vertical changes in facies. they are therefore lithostratigraphic units and, at the same time, are allostratigraphic and “mappable” (figs. 5 and 6). their areal distribution, cyclic organisation and bounding surfaces are discussed below in section 6.1. geologia croatica 64/2geologia croatica 104 5.1. basal alluvium (u1) 5.1.1. description unit 1 is up to 400 m thick, starts above the middle eocene foraminiferal limestones and local bauxite deposits (figs. 5, 6), and consists of two alternating facies associations. the fi rst one is represented by sheet-like conglomerate bodies, up to several metres thick, and more than 100 m wide, which include lenses and thin intercalations of horizontally and crosslaminated calcarenites (fig. 7/1). the conglomerates of these bodies are horizontally bedded to gently inclined, with b-axis imbrication pointing towards the s to sw, and are rarely, cross-bedded. they may be erosionally based with up to 40 cm deep scours, and may pinch out. the second facies association includes mudstones, calcarenites, and minor conglomerates. the mudstones may contain silt and calcarenite laminae, are bioturbated, and display rhizocretions, pedotubules, reddish mottling and pedogenic nodules. calcarenites are up to 30 cm thick and either horizontally laminated, crossbedded or current-ripple laminated. they commonly display plant debris, leaves, stems, and branches, as well as pedogenic alteration. conglomerates and calcarenites rarely form less than 1 m thick channel-fi lls encased in calcarenites and mudstones. a few, up to 60 cm thick, matrix-supported conglomerates occur in the middle-upper part of the unit. locally deformed bedding might represent traces of former tree stumps. in contrast to the high predominance of cretaceous and middle eocene lithoclasts typical for the pb as a whole, the upper part of the unit contains clasts of other formations. they include triassic dark limestones and dolomites, similar carbonates which may be jurassic and/or permian in age, eocene limestone breccias, as well as conspicuous lower triassic, violet sandstones and ooid grainstones. some calcarenites are composed of 5-30% non-carbonate particles. there are also minor coated pebbles, oncoids, cylindrical stromatolites and stromatolite intercalations (fig. 8). the later may include calcifi ed cyanobacterial fi laments, gastropods and ostracods. 5.1.2. interpretation the features of sheet-like conglomerate bodies suggest the activity of braided streams, characterised by longitudinal bars and intervening channels, with cross-bedded conglomfigure 5: geological map of stratigraphic units of the pb in mtp described here. areas close to and including the lower lacustrine unit (u2) is poorly exposed and structurally complex and its boundaries may be tectonised. gilbert deltas are more numerous than presented. for discussion see text. zupanič and babić: sedimentary evolution of an inner foreland basin margin: palaeogene promina beds of the type area, mt. promina... geologia croatica 105 figure 6: successions of the pb in mtp. u1-u7, sedimentary units. su, subaerial unconformity. sb, sequence boundary. mrs, maximum regressive surface. t/r, transgressive-regressive turnaround. mfs, maximum fl ooding surface. some bodies assigned as gilbert deltas may possibly represent beach deposits. for location see fig. 5. for explanation see text. erates deposited at fronts and/or fl anks of the bars (reviews in collinson, 1996; miall, 1996). some calcarenites in these bodies are erosional relics, while others fi ll scours originated during the falling river fl oods. the sheets indicate wide channel belts. the second facies association originated in fl oodplains most of which have been vegetated as indicated by pedogenic alteration, and locally contained smaller channels. laminated and cross-bedded calcarenite beds have been deposited by sheet-fl oods over the fl oodplains. the palaeotransport was directed towards the ssw. rare debrisfl ow conglomerates possibly indicate a short-term proximity to alluvial fans. carbonate precipitation during the upper part of the unit took place in stream channels, while some stromatolite intercalations may indicate short-lived ponds (cf. anadón & zamarreňo, 1981). the precipitation was mediated microbially, as suggested by cyanobacterial fi laments. these carbonates indicate a lot of available water and dense veggeologia croatica 64/2geologia croatica 106 figure 7: illustrative segments of successions in fig. 6. for vertical position of logs see fig. 6. zupanič and babić: sedimentary evolution of an inner foreland basin margin: palaeogene promina beds of the type area, mt. promina... geologia croatica 107 5.2. lower lacustrine unit (u2) unit 2 (figs. 5, 6, 7/2) includes a 0.2 m thick clay horizon with coal laminae containing gastropods, and overlying, lami nated limestones, a few metres thick (fig. 9), with ostracods, cyanobacterial fi laments, characean encrustations and gyrogonites, gastropods, bivalves, and plant leaves. the clay with coal laminae is probably a lateral equivalent of the “2nd bed” or “lower bed” of miners cited by nikler (1982), and marković (2002). the clay layer with coaly intercalations probably originated in a swamp. it was followed by a shallow carbonate lake characterised by microbial mats, and typical lacustrine biota (review in tucker & wright, 1990). 5.3. lagoon to alluvium (u3) 5.3.1. description the thickness of unit 3 varies from 80–150 m. its lowermost part is either tectonised with possible small-scale repetitions, or covered by vegetation. it possibly includes an iso lated outcrop (“?” in fig. 6e), consisting of 3 m of marl and 1.3 m of stromatolites. above the covered interval there is an alternation of mudstones, calcarenitic mudstones, and calcarenites which may contain very rare, smaller benthic foraminifera (fig. 7/2). minor conglomerate intercalations also occur. in the upper part of this segment, rhizoliths, nodular palaeosols, and plant remains become common, while foraminifera disappear. conglomerates may show basal scours, and occasionally fi ll shallow channels oriented n-s. the thick er, upper part of the unit is laterally variable. it may be dominated by alternating sheet conglomerates with an average palaeotransport towards the south, and pervasively pedifi ed calcarenites and mudstones (fig. 10), thus resembling unit 1. the upper part may also include a package of massive, poorly sorted, pebble to boulder conglomerates (fig. 11), with clasts attaining 2 m in diameter and minor, pedifi ed calcarenites (fig. 7/3). some of the later conglomerates show inverse grading in their basal part, and others have protruding large clasts at the top (fig. 7/3). this sediment package forms prominent rocky walls on the sw mountain slo pes. 5.3.2. interpretation a rare marine fauna, represented by smaller benthic foraminifera, contrasts its common occurrence in other shallowfigure 8: stromatolite intercalation in alluvial conglomerates of u1 is laterally (right) combined with protruding and domal forms. lens cap is 4.4 cm in diameter. sv. ivan in fig. 5. figure 9: laminated lacustrine limestone of u2. hammer is 32 cm long. log d, 466 m in fig. 6 (see also fig. 7/2). figure 10: floodplain palaeosol mudstone with calcite cemented tubes of former root hairs and partly developed alveolar-septal fabric (upper left and lower right). u3. log b, 565 m in fig. 6. figure 11: detail of a debris fl ow unit. u3. hammer is 32 cm long. log b, 525 m in fig. 6. etation. nikler (1982) and marković (2002) cite a thin coal seam (“3rd bed” of miners), which seemingly belongs to the upper part of the unit. if so, a fl oodplain swamp also existed. geologia croatica 64/2geologia croatica 108 marine deposits of pb, and might refl ect restricted marine conditions for the lower part of the unit, where clastics presumably derived from a river mouth. the setting was probably a lagoon. it subsequently evolved into a vegetated coastal plain, as suggested by pedogenic features occurring upwards. hence, one might envisage a delta (“shelf delta” of ethridge & wescott, 1984) prograding into the lagoon. this environment was followed by alluvial settings including fl oodplains and channel belts, similar to those in u1, as well as a local, interfi ngering alluvial fan(s) characterised by common debris fl ows. the isolated outcrop of marls and stromatolites possibly corresponding to the lowermost part of the unit could represent a local lacustrine episode following the lagoonal onset of the unit. 5.4. middle lacustrine unit (u4) 5.4.1. description unit 4 (figs. 5 and 6) is laterally variable. to the sw (figs. 7/3, 7/4) there is a discontinuous, up to 1 m thick clay horizon with lignite laminae and 8 m of brown limestones. the later are mostly laminated, and display cyanobacterial fi laments, ostracods, bivalves, and gastropods, less characean encrustations and gyrogonites (fig. 12a), and leaves. packstones and wackestones with the same components also occur, as well as minor oncoidal limestones. to the e, there is succession of coaly rocks, clastics, and limestones (fig. 7/5) up to 34 m in thickness. of two subunits of coaly sediments, the lower one is lignite, while the upper one is coaly shale with molluscs. together they have been referred to as the “main bed” or “1st bed” by miners (nikler, 1982; marković, 2002). limestones comprise three subunits. they are strongly weathered, except for a 4 m thick, upper segment which is similar to limestones in the sw area (fig. 12b). weathered sediments locally include stromatolites with molluscs, characean encrustations, gastropods, bivalves and ostracods, traces of carbonaceous material, as well as marly and clayey laminae and possible lacustrine chalk intercalations. organic material was probably responsible for dissolution of much of the carbonate, and for the strong weathering. the sub-unit of calcarenites and conglomerates is 2 4 m thick. the calcarenites include limefigure 12: lacustrine limestones of u4. (a) thin section of mudstone with characean gyrogonites. log c, 576 m fig. 6. (b) horizontally and wavy laminated limestone. lens cap is 4.4 cm in diameter. log f, 595 m in fig. 6. stone clasts, coated grains, stromatolite fragments, ostracods and mollusc debris, and 5–30% non-carbonate particles. pebbles in the conglomerates may be coated by microbial laminae. 5.4.2. interpretation the lignite (nikler, 1982) originated from peat accumulated in forest swamps (e.g. tucker, 2001). hogs and croco diles (kerner, 1901) inhabited such environments. lami nated limestones including microbial laminae originated in carbonate lakes (review in tucker & wright, 1990), and the same is true for weathered carbonates. a transitional setting with seasonally(?) alternating swamp and lake conditions resulted in alternating carbonate and carbonaceous laminae. as the clastic sub-unit lacks typical marine biota and is associated with lacustrine and swamp deposits, it may represent a lacustrine delta episode. 5.5. shelf/delta alternation (u5) 5.5.1. description unit 5 is up to 300 m thick and wedges out laterally (figs. 5, 6, 24, 26). it starts with marls, which contain common plant debris and leaves, smaller benthic and planktonic foraminfigure 13: bioturbated foraminiferal packstone from a tempestite intercalation in shelf mudstones. tests of discocyclina, operculina and nummulites (among others) are readily observed. u5. log k, 844 m in fig. 6. figure 14: below the prominent bedding plane, calcareous mudstones with three calcarenite intercalations (ca), and one foraminiferal packstone (f) are visible. above, there is a 14 cm thick calcarenite overlain by a debris fl ow conglomerate. u5. lens cap is 4.4 cm in diameter. log g, 668 m in fig. 6. zupanič and babić: sedimentary evolution of an inner foreland basin margin: palaeogene promina beds of the type area, mt. promina... geologia croatica 109 figure 15: a 2 m thick slump unit involved alternating calcarenites and mudstones, which also occur below and above the slump. u5. sw slope of mtp. figure 16: most of the prominent rocky walls are formed by conglomeratedominated bodies including bottomset, foreset and topset beds of gilbert deltas. some of these bodies possibly originated as beach deposits. they alternate with intervals of shelf deposits which are mostly covered by vegetation. u5. the thickest body (up to 12 m) in the middle shows left-inclined traces of foreset beds. log h in fig. 6 includes sediments of the lower and middle parts of the photo (between 740 and 804 m). ifera, and scattered molluscs (figs. 7/4, 7/5), and may be dark at the very base. upwards, mudstones may be intercalated by bioturbated lime packstones (fig. 13) up to 8 cm thick containing larger foraminifera (e.g. operculina, discocyclina, nummulites, asterigerina, sphaerogypsina), smaller benthic and planktonic foraminifera, molluscs, corallinaceans, rare microcodium debris, and limestone clasts. these are over lain by an alternation of mudstones, thin, graded, and horizontally laminated calcarenites, slumps including mudstones and calcarenites, massive, graded, and inverse to normally graded conglomerates, and foraminiferal packstones (figs. 14, 15). the calcarenites may be rich in plant debris and leaves, and may contain foraminifera. there are also up to 2 m thick packages of mudstones intercalated with calcarenite laminae which contain plant material. in a restricted area (čolovići, fig. 5) intercalations of specifi c massive conglomerates can be seen, which include clasts of limestone breccia, bored peb bles, molluscs, corals and benthic foraminifera. they disappear basinwards. the main part of the unit consists of (a) lensoid, mainly conglomeratic bodies consisting mostly of bottomset, foreset and topset beds, and (b) a heterogeneous facies of alternating mudstones, calcarenites, and lesser conglomerates, which displays features similar to the lower part of the unit. lensoid bodies appear either isolated within the heterogeneous facies, or closely stacked vertically and/or laterally (fig. 16). towards the ne, the unit becomes thinner, highly dominated by mudstones, and includes only one lensoid body (fig. 6k). the bottomsets of the lensoid bodies include up to 50 cm thick, massive conglomerates, and up to 30 cm thick, horizontally laminated calcarenites, locally rich in plant debris and leaves. both of them may wedge out (fig. 17). foresets are 4–15 m thick (fig. 18), with most common inclinafigure 17: toeset to bottomset transition of a gilbert delta. debris fl ow conglomerates alternate with laminated calcarenites. the prominent conglomerate wedge thinning from left to right is a termination of a fl ow tongue. u5. between logs i and j, about 875 m in fig. 6. hammer is 32 cm long. figure 18: up to 15 m high delta foresets. u5. log i, about 865 m in fig. 6. geologia croatica 64/2geologia croatica 110 deposited them as tempestite lime packstones. graded and laminated calcarenites may have resulted from surge-type fl ows, while segments of alternating mudstone/calcarenite laminae might refl ect fl uctuating hyperpycnal fl ows. both processes were presumably related to river fl oods. the modifying infl uence of storms inferred for correlative sediments in other parts of the promina basin (babić & zupanič, 2007) has not clearly been recognised in these calcarenites. conglomerates have been deposited by debris fl ows and high den sity turbidity currents which may be related to delta slope failures (see below). local intercalations of fossiliferous, massive conglomerates (čolovići) are debris-fl ow deposits, possibly derived from a locally existing, fault-bounded coast. the origin of the majority of lensoid bodies (a) is related to processes operating in gilbert-type deltas (cf. postma & roep, 1985; massari & colella, 1988; nemec, 1990; chough et al., 1990; postma, 1990). they prograd ed by accretion of steeply inclined, mass-fl ow conglomerates over bottomset beds, which in turn, overly shelf sediments (fig. 19). the bottomset conglomerates indicate de position from debris-fl ows originating from delta slope failure events (cf. postma & roep, 1985; postma et al., 1988), while associated, upper plane bed calcarenites may have been deposited from hyperpycnal fl ows related to river fl oods (e.g. prior & bornhold, 1990). truncation surfaces, and clastic topsets with marine fossils refl ect marine erosion, reworking, production of a transgressive lag, probable beach deposits (pebble-thick units), probable bars (cross-beds), and shoreface sands (wave ripples). the fi ning upward trend suggests an upward decreasing marine energy and increasing depth. this was followed by deposition of limestone, probably still farther from the shoreline. marine topsets are well known from gilbert deltas (e.g. massari & colella, 1988; postma & cruickshank, 1988), including those re ported from other parts of the promina basin (postma et al., 1988; zupanič et al., 1987, 1988; babić & zupanič, figure 20: bioturbated foraminiferal packstone with nummulites, discocyclina, operculina and asterocyclina of the gilbert delta topsets. u5. log h, 752 m in fig. 6. figure 19: ideal shelf-delta cycle (subcycle), i.e. lower order t-r sequence, based on examples from mtp. variants of this sequence constitute u5 (=shelf-delta alternation). rs, fs are transgressive ravinement, and fl ooding surfaces, respectively. t/r: transgressive/regressive turnaround. for sym bols not explained above, see fig. 7. for discussion see paragraph on sedimentary cycles. tions of 15° to 26°. directions of inclinations are scattered between n and s with an average direction towards the wsw. they include massive to crudely stratifi ed conglomerates, and occasional calcarenites. the foresets are unconformably overlain by up to 30 cm thick conglomerates and/ or calcarenites, which may display fi ning upward successions (fig. 19). an exemplary section includes an imbricate conglomerate with a transport direction towards the ene which is followed by a cross-bedded conglomerate bed, a one pebble thick layer, and a wave-rippled calcarenite. the clastic topsets may be overlain by 1 to 30 cm thick limestones (fig. 20). both the clastic topsets and limestone may contain benthic foraminifera and molluscs. lensoid bodies may be distorted and/or faulted at their margins, and broken into rotated blocks. 5.5.2. interpretation the lowermost part of the unit refl ects a shelf setting based on muddy sediments with smaller benthic and planktonic foraminifera. local, dark mudstones of the very base have presumably been deposited in a restricted (lower salinity?) environment, related to initial, marine ingression into previous, lacustrine areas. subsequently, the shelf became infl uenced by occasional, storm-related processes, which collected and concentrated particles from both the marine (e.g. foraminifera) and subaerially exposed (e.g. microcodium) areas, and zupanič and babić: sedimentary evolution of an inner foreland basin margin: palaeogene promina beds of the type area, mt. promina... geologia croatica 111 1990, 2007). such marine topsets differ from those originally described as fl uvial topsets (gilbert, 1885). the similarity of the heterogeneous facies (b) to the lower part of the unit suggests a shelf setting infl uenced by sediment supply from rivers and delta slope failure events. the origin of the alternation of (a) and (b) facies associations is discussed in sections 6.1.3.2. and 6.2. aside from the lensoid bodies discussed above, there are conglomerate lensoid bodies which probably represent beachface deposits comparable to those described by massari & parea (1988) from the apenninic pleistocene. their “foreset” beds display lower inclination angles, while their other features are generally poorly visible and they are not discussed further. deformation of the lensoid bodies was probably related to instability of deltaic systems. instability events may have been the result of seismic activity at the basin margin, which could also be the case for common slumping, as well as common delta slope failures. 5.6. fossil-rich limestones (u5a) unit 5a consists of up to 10 m thick, poorly bedded limestones which overly eocene and cretaceous platform carbonates, local bauxites, and sporadic carbonate breccias and conglomerates. the unit is restricted to the n part of the study area (figs. 5, 6). the limestones are bioclastic packstones, rudstones and wackestones, and include larger foraminifera (e.g. common discocyclina), smaller benthic foraminifera, bivalves, corals, gastropods, echinoids, and coral linaceans. glauconite and planktonic foraminifera are found on top of the limestones, just below the marls of u5 (figs. 21, 22). the rich shallow-marine biota suggest shallow-marine, carbonate environments established above former terrestrial areas, while glauconite and planktonic foraminifera at the top of the unit imply sediment starved conditions at the transition to overlying shelf marls of u5. 5.7. upper lacustrine unit (u6) small, isolated outcrops, which might be one to a few metres thick, occur within a smaller area on the sw slope of the mountain, between units 5 and 7. unit 6 is not reliably identifi ed along the entire line shown on the map (fig. 5), and it possibly pinches out landwards. the outcrops include lime wackestones and mudstones with characeans, ostracods, molluscs, probable cyanobacterial fi laments, and plant leaves. these features refl ect deposition in a shallow carbonate lake (review in tucker & wright, 1990). 5.8. terminal alluvium (u7) 5.8.1. description outcrops of unit 7 display sheets of massive to crudely bedded conglomerates (figs. 7/6 and 23), which include calcarenite lenses. they alternate with packages consisting of horizontally laminated, cross bedded and current-rippled cal carenites and mudstones. b-axis imbrication in conglomerates points towards the w to sw. the sheets may include crossbedded conglomerates. many mudstones and some calcarenites display reddish mottling, rhizocretions, and pedogenic nodules (fig. 7/6). plant remains are common in the mudstones and calcarenites, which include a reworked tree trunk replaced by calcarenite. calcarenites containing up to 30% non-carbonate particles are exceptional, as well as conglomerates including isolated sandstone clasts. there are also shal low scours fi lled by conglomerates. in the ne part of the study area, the unit overlies u5a and the cretaceous basement (figs. 5, 6) (for discussion see section 6.1.3). the total thickness of u7 is about 120 m. figure 21: poorly bedded sediments of the fossil-rich limestones (u5a) (below geologist) are overlain by a 60 cm thick condensed unit (below geologist’s hand) of packstones and wackestones with glauconite. the later are overlain by regressive shelf mudstones with calcarenite intercalations (u5). ne part of mtp (between point 495m and bukovac in fig. 5). figure 22: foraminiferal packstone of the condensed horizon in fig. 21 includes green glauconite (arrow). geologia croatica 64/2geologia croatica 112 5.8.2. interpretation sheet conglomerates may have originated in braided channel belts, while the association of calcarenites and mudstones refl ects deposition in vegetated fl oodplains. the depositional processes and environments resemble those of u1 and uppermost u3. similar alluvial sediments have been described from the continuation of this unit, in the nw part of the basin (fig. 4). 6. discussion 6.1. depositional cycles the vertical succession(s) of sedimentary units of the pb of mtp described above shows a cyclicity related to variations in accommodation space and sediment supply, which is the objective of sequence stratigraphic analysis, as defi ned by posamantier & allen (1999). three main cycles have been recognised, in which the sedimentary units are treated as sequence stratigraphic units (fig. 24). 6.1.1. cycle i (u1) the unconformity and coincident sequence boundary, which separate middle eocene carbonates and basal alluvium (u1), extend basinwards, away from mtp, by truncating lower, marine pb (older than pb at mtp), with a distally diminishing hiatus (fig. 25a) (babić & zupanič, 2007). still farther basinwards, there is an erosional surface interpreted as the basal surface of forced regression of hunt & tucker (1992) which is overlain by forced regressive sediments (mrinjek, 2008). it seems to represent a distant continuation of the basal sequence boundary at mtp. the basal alluvium (u1) therefore, might have been deposited during the relative sealevel rise of the late lowstand by onlap onto the deformed basement (fig. 25a). a high water table during the upper part of the unit (section 5.1) may be related to high sea-level, which continued to rise further during the next cycle. in the nw part of the promina basin, alluvial deposits of similar stratigraphic position have not been recognised (mrinjek & pencinger, 2008), and cycle i of mtp possibly continues laterally and seaward into alternating shelf and shoreface deposits reported by these authors. figure 23: crudely bedded conglomerates deposited in a longitudinal bar of a braided system. u7. hammer is 32 cm long. log j, 965 m in fig. 6. figure 24: stratigraphy of the pb of the main (southern) and marginal (northern) parts of mtp. k and e are cretaceous and eocene carbonates, respectively. thickness of lacustrine units and fossil-rich limestones (u5a) is exaggerated. for explanation see text. 6.1.2. cycle ii (u2, u3) the origin of swamp and carbonate lake environments (u2) above former alluvium (cycle i; fig. 25b) must have been related to a rise of the water table and related sea-level, which were already high. namely, the rising base level will concomitantly raise the groundwater table, and cause poorer drainage in alluvial systems, which lead to widespread development of swamps and lakes (shanley & mccabe, 1994). the process also caused a landward shift of alluvial systems. the coastal lowlands with lacustrine environments were subsequently submerged becoming a lagoon (lower u3) by further rise of relative sea-level. the base of cycle ii, therefore, corresponds to the transgressive surface of sequence stratigraphic systematics (posamantier & vail, 1988; posamantier & allen, 1999). this type of stratigraphic surface is typically formed by marine ravinement processes, while in our case, the onset of the low-energy settings of swamps and lakes didn’t cause reworking and/or erosion, hence, the relevant boundary may be better termed maximum regressive surface (helland-hansen & martinsen, 1996). while the carbonate lake above the swamp deposits (u2) refl ects an increase in the rate of relative sea-level rise compared to sedimentation rate, i.e. a transgression, the subsequent lagoon-delta-alluvium succession (u3) displays an overall progradation related to an increased sedimentation rate compared to relative sea-level rise, i.e. a regression. transgressive to regressive turnaround may be located at the top of lacustrine limestones, while maximum fl ooding might correspond either also to this surface or it occurs a little bit higher zupanič and babić: sedimentary evolution of an inner foreland basin margin: palaeogene promina beds of the type area, mt. promina... geologia croatica 113 (see discussion by catuneanu, 2006). possible repetition of lake and lagoonal sediments at the very base of the cycle, might suggest the presence of a small, transgressiveregressive subcycle before the onset of the main part of the succession discussed above. in general (fig. 24/main area), the lower part of cycle ii (u2) corresponds to the transgressive systems tract of the sequence stratigraphic approach (e.g. posamantier & vail, 1988; posamantier & allen, 1999; catuneanu, 2006), and its upper part may be designated either as a highstand or a regressive systems tract. the fi rst choice considers a depositional sequence of posamantier & vail (1988), which would consist of a lowstand tract (cycle i) and a transgressive plus highstand tract (cycle ii). the later option considers cycle ii as a transgressive-regressive (t-r) type of sequence (embry & johannesen, 1992; embry, 2002), with the sequence boundary coinciding with the maximum regressive surface. in other parts of the basin, the lower part of cycle ii can not be clearly identifi ed. in the nw basin area, it is possibly represented by shelf to shoreline cycles reported by mrinjek & pencinger (2008). in contrast, its upper, alluvial part, as well as its termination at the transgressive surface is easily recognised throughout most of the basin (babić & zupanič, 2007; fig. 4). 6.1.3. cycle iii (u4-u7) 6.1.3.1. lower part (u4). the transition from cycle ii to cycle iii resembles the transition from cycle i to cycle ii in the change from alluvial to lacustrine deposition (u4) at the maximum regressive surface (fig. 24/main area). at this point, the increase in accommodation space surpassed the sedimentation rate, but didn’t yet enable a marine ingression (see discussion on cycle ii, section 6.1.2). this surface and the overlying middle lacustrine unit (u4) in mtp correlate basinwards with the transgressive surface (= ravinement surface = transgressive surface of erosion of posamantier & vail, 1988; posamantier & allen, 1999), and the overlying tst consisting of wave-worked clastics and limestones (babić & zupanič, 2007)(figs. 4, 25d). hence, the middle lacustrine unit (u4) is regarded as a non-marine, proximal segment of the transgressive tract. where u4 consists of several smaller units of swamp, carbonate lake, and lacustrine delta (fig. 7/5), this may refl ect very restricted, short-term changes in the relationship between accommodation space and sedimentation within the overall transgressive trend. 6.1.3.2. middle part (u5, u5a). the change from lacustrine to shelf/delta settings marks the onset of progradation, i.e. the onset of a highstand or regressive systems tract. maximum fl ooding may be regarded as occurring within basal mud stones (a few metres thick), with benthic and planktonic foraminifera (babić & zupanič, 2007) (fig. 6). the sea fl ood ed not only previous lacustrine realms, but also spread farther landwards (nne), which resulted in the coastal onlap of fossil-rich limestones (u5a) onto the basement, and related subaerial unconformity (figs. 5, 6a, 6k, 24, 25d). kerner (1901) placed these limestones at the base of the pb, while for quitzow (1941), they are a coastal equivalent of mudstones (equivalent here to the lowermost u5). deposition of these limestones ended with sediment starvation, i.e. maximum fl ooding (figs. 21, 22). alternating shelf and delta deposits (u5) refl ect repetitions of lower order cycles or subcycles, within an overall trend of rising relative sea-level. a “modal” subcycle of this type consists of two parts (fig. 19). the transgressive part starts above a ravinement surface, and includes a fi ning upward succession refl ecting decreasing marine energy levels associated with landward shift of facies, and limestones which may be regarded as a condensed section related to figure 25: evolution of the inner part of the promina basin including mtp area. u1 to u7 are sedimentary units. fig. d shows correlation of lacustrine tst (u4) in mtp and marine tst basinwards. the same fi gure includes the proposed correlation of transgressive fossil-rich limestones (u5a) and the basal, dark, muddy part of the shelf-delta alternation (u5). in fig. g, dashed line at the top of alluvial sediments (u7) highlights the youngest deformation (it marks neither the top of the unit nor a depositional surface). thick arrows indicate relative movement of tectonic units. not to scale. for explanation see text. see also figs. 26 and 28. geologia croatica 64/2geologia croatica 114 maximum fl ooding. this part refl ects increasing accommodation space and decreasing sediment supply. the regressive part embraces shelf deposits and overlying delta. repetition of such t-r cycles or subcycles was related to an overall relative sea-level rise, which was punctuated by stillstands when deltas prograded (postma, 1995). the driving factors are discussed in section 6.2. lower delta bodies appear isolated in shelf sediments, and are only exceptionally closely superimposed or juxtaposed, while deltas higher in the succession are more densely distributed (fig. 6). this suggests a gentle, average upward decrease in overall relative sea-level rise. 6.1.3.3. upper part (u6, u7). as neither lateral continuity, nor bounding surfaces of the upper lacustrine unit (u6) have been identifi ed, one can only speculate on possible trends. the fi rst scenario envisages a continuation of an overall regression, from previous shelf to delta (u5), to the coastalplain and/or delta-plain lakes (u6), and to the alluvium (u7). the later display a landward onlap (figs. 24, 25f, 26), and the conditions would correspond to the late highstand of pos amentier & allen (1999). a second scenario includes a smaller fall in relative sea-level which ended marine deposition, provoked erosion (not identifi ed as yet) and the origin of a sequence boundary (sensu posamentier & allen, 1999). subsequent lacustrine and alluvial deposits would correspond to the late lowstand. this scenario implies the end of cycle iii and the onset of a new cycle at an envisaged unconformity i.e. sequence boundary. in the third scenario, the lake(s) succeeded deltas, and were followed by the sequence boundary and alluvium. this would imply the end of cycle iii and the onset of a new cycle, at the base of the alluvium (u7). the fi rst scenario is favoured, however, with only modest support by the presumable lack of sediments deposited during relative sea-level fall. as a whole, and if the favoured scenario is accepted, cycle iii consists of transgressive and regressive segments (fig. 24) which might be denoted either as transgressive and highstand systems tracts or as the transgressive-regressive sequence as discussed for cycle ii (section 6.1.2). 6.1.3.4. other parts of the basin. cycle iii extends along the entire promina basin. marine tst represented by wavework ed clastics and fossiliferous limestones, which replaces lacustrine tst (u4) of mtp basinwards (figs. 4, 25/d), also occurs in the distant, nw basin area (fig. 4) where mrinjek & pencinger (2008) describe a transgressive tract consisting of mudstones with rare calcarenites (at the base of their unit 4). these deposits, however, belong to the lower part of the subsequent, regressive unit, which is similar in character across the entire promina basin (babić & zupanič, 2007), and corresponds to u5 in mtp. similarity in the sedimentary evolution along the basin is also shown by reconnaissance data on lacustrine sediments occupying the same stratigraphic position in the nw basin area as they do on mtp (u6), i.e. between marine and alluvial units (u5 and u7 on mtp). other features, identical for both mtp and the 80 km long ne basin margin, include marine and alluvial onlaps (u5a and u7 on mtp), both of which are related to an unconformable surface above bauxite deposits and the cre taceous to eocene basement (babić et al., 1995). this indicates a similar stratigraphy along the inner basin margin. 6.2. the main controls on sedimentary evolution structural and stratigraphic relationships, together with other features described above, as well as the available data from other parts of the promina basin, are used in an attempt to detect which factors were dominant in the sedimentary evolution of the basin margin. deposition of pb in the study area was preceded by important deformation, which was responsible for a major basinward shift of the shoreline, i.e. the subaerial exposure of a major part of the basin. the subsequent onlap by a thick, dominantly coarse-grained alluvial unit (u1) regarded as corresponding to the late lowstand conditions (see 6.1.1, fig. 25a), refl ects a high sediment supply from a mountainous catchment area in the orogen. this and the vertical change in the detritus composition may suggest active tectonics during deposition. the upper part of u1 contains additional, old er detritus compared to its lower part (section 5.1.1.). the change does not seem to have been caused solely by the erosion of deeper basement rocks and lowering of relief, as the average grain size didn’t decrease. it is proposed that a nearcontinuous tectonism in the catchment area had a direct sedimentary response in the form of a thick, coarse-grained alluvial unit (fig. 25a) in the subsiding basin. the conditions might have been similar to those proposed for some fan-delta wedges in the ebro foreland basin, spain, where the depositional dynamics are regarded to have been principally infl uenced by high sediment supply related to continuous tectonic activity (lopez-blanco et al., 2000; marzo & steel, 2000). the origin of the subsequent lacustrine tst (u2), which is presumably replaced basinwards by a marine tst (section 6.1.2, fig. 25b), may be related to a backtilting of the proximal part of the basin, which generated a “ponded” area, isolated from direct marine infl uence. this might have occurred by a tectonic pulse which caused increased subsidence rates and a landward shift of coarse-grained sedimentation, as proposed in models by heller et al. (1988) and burns et al. (1997). a similar effect might have resulted from a eustatic rise, which accelerated relative sea-level rise in the proximal part of the foreland basin characterised by increased subsidence rates compared to the distal part (posamentier & allen, 1993). the sharp, but non-erosive transition from the coarse-grained alluvial to lacustrine settings seems to favour the fast tectonic process as dominant. the subsequent regressive unit (u3) doesn’t seem to have been deposited in the n area, and lower units (u1, u2) are also lacking there. alternatively, the latter could have been deposited in that area, at least in small thickness, and were erosionally removed from the uplifting block and resediment ed basinwards (fig. 25c). the rarity of older detritus types, which were quite common in the upper part of u1, may be explain ed by an important contribution from the denudation of the cretaceous and eocene basement uplift, additional contribution zupanič and babić: sedimentary evolution of an inner foreland basin margin: palaeogene promina beds of the type area, mt. promina... geologia croatica 115 from the hinterland, and a partial transfer to the distal basin. a laterally impersistent alluvial fan(s) indicates local, more intense, short-term fault activity within the uplift or at its margin. the envisaged situation is partly similar to the “postorogenic phase” of heller’s et al. (1988) two-phase mo del of foreland-basin sequences, in which reworked, coarse deposits in distal foreland basin correlate with erosion and an unconformity in the proximal part of the basin. however, the syndepositional faulting inferred to be related to the origin of coarse-grained alluvial fans, may have been a part of a nearcontinuous tectonic loading and subsidence, refl ected in the dominant role of high sediment supply in generating the regressive trend (as previously discussed in relation to u1). abrupt termination of the alluvial deposits (u3), and the following lacustrine tst (u4) resemble the transition from the alluvial u1 to lacustrine u2, and are considered to refl ect the same main driving process. these include a tectonic pulse, which was responsible for backtilting and the development of lacustrine tst in the proximal part of the basin, and marine ravinement with marine tst in its distal part (fig. 25d: left, lower part). as this transgressive trend characterises a major part of the basin (fig. 4; babić & zupanič, 2007), local and/or intrinsic processes were not critically relevant. at the local scale however, gentle tectonism may have been infl uential, as suggested by the lateral difference in sedimentary succession and thickness of u4 (figs. 6, 7/3, 7/4, 7/5) which resulted from small-scale, syndepositional downwarping. subsequently, there was a short transitional evolutionary interval, when the very beginning of the regression correlates with marine onlap onto the basin margin (basal u5 and u5a; fig. 25d: upper left and right). during deposition of u5 the proximal part of the basin experienced complex processes and specifi c changes which include the origin of growth folds and associated growth stra ta, and proximal-distal difference in the character and thickness of the unit (figs. 5, 6, 24, 25e, 26). these processes were probably related to advancing thrusts which increased subsidence rates and induced an overall relative sealevel rise. as the average wsw direction of the progradation of deltas (with a variation between n and s) contrasts s to sw palaeotransport directions in u3 alluvium, a major part of the detritus appears to have been supplied from source areas which appeared roughly ene of today’s mtp (diagonal to the section in fig. 25e) (fig. 27). the envisaged structural bending was possibly combined with dextral, transpressive faulting which might represent an earlier stage of the large, diagonal fault system, which today passes several kilometres e of mtp (chorowicz, 1977). the modulation of overall relative sea-level rise during u5, by lower-order relative sea-level changes, which produced lower-order t-r cycles (section 6.1.3.2.), may have resulted from episodic subsidence along the marginal fault(s). this is in agreement with the opinion that vertical stacking of gilbert deltas refl ects high subsidence rates close to tectonically active basin margins (colella, 1988; gawthorpe & colella, 1990; dorsey et al., 1995). moreover, the model for gilbert delta stacking in the loreto basin, baja california sur by dorsey et al. (1997) relates alternating episodes of rapid subsidence and transgressions with closely repeating slips along marginal faults which induced earthquake clustering, while deltas prograded during tectonic stillstands. this model may be relevant for the examples on mtp. however, local differences in sediment supply and intrinsic factors such as switching of delta lobes may have induced the origin of some t-r sequences. in general, the overall regressive trend of u5 together with its internal t-r dy namics may have been dominantly induced by the combination of subsidence and sediment supply. before or at the very beginning of u7, the marginal part of the basin experienced uplift and erosion which involved deformed carbonate basement, u5a, u5 and u6(?) of that area. the resulting truncation surface was onlapped by alluvial u7 and also represents an angular unconformity, which quickly dies out basinwards (ssw) (figs. 25f, 26, 28). it corresponds to the “progressive and angular unconformity” described by riba (1976) from the se pyrenees, where it figure 26: geological sketch of the northern mtp (view towards the w), showing the complex stratigraphy and structure of the basin margin. lower part shows growth folds with associated growth strata. they were subsequently deformed again and cut by an angular unconformity at their n end (su, upper right). the youngest deformation involved the entire succession. thickness of fossil-rich limestones is exaggerated. symbols as in fig. 24. length of the area is about 1.5 km. k and l are locations of two logs in fig. 6. point 1147 m is the top of mtp. based on fi eld data and photographs. see also fig. 28. figure 27: presumed position of mtp (framed) relative to hypothetical basin margins during deposition of the shelf-delta alternation (u5). symbols for deltas show representative directions of their progradation. deltas belong to diff erent time intervals. the average wsw progradation is assumed to indicate the existence of n-s and nnw-sse oriented basin margin. not to scale. for details see text. geologia croatica 64/2geologia croatica 116 may represent part of a series of synsedimentary unconformities related to deformational pulses (riba, 1976; ford et al., 1997). the present-day thickness and extent of regressive u7 on mtp resulted from considerable denudation during the neogene to recent (figs. 5, 6). based on data from neighbouring and other parts of the basin this unit assumed a thickness of more than 300 m and extended about 5 − >10 km basinwards (fig. 4/3; babić et al., 1995). this suggests that the regressive trend of this unit was dominantly induced by a high sediment supply. it was presumably related to nearcontinuous tectonic loading and erosion of thrust units, as suggested by lopez-blanco et al. (2000) and marzo & steel (2000) for some fan-delta clastic wedges in the ebro basin, spain. a younger deformation postdating the pb at mtp involved the marginal, nne basin area. the resultant, gentle folding is similar in orientation to the previous one, and also decreases in intensity basinwards (figs. 25g, 26, 28). 7. conclusion in their type area, mtp, the pb are represented by 8 sedimentary units, which differ in facies and/or facies associations, i.e. depositional environments and systems. they are both lithostratigraphic and allostratigraphic units, are objectively identifi able and mappable. they are: basal alluvium (u1), lower lacustrine unit (u2), lagoon to alluvium (u3), middle lacustrine unit (u4), shelf/delta alternation (u5). fossil-rich limestones (5a), upper lacustrine unit (u6), and terminal alluvium (u7). there is a considerable variation in se dimentary suc ces sions laterally: in the proximal part of the basin u1u4 is missing, u5 varies in character, while u5a is exclusive only to this part of the basin. the sedimentary units are arranged in 3 depositional cycles. cycle i (u1) is believed to correspond to late lowstand conditions, while cycles ii (u2, u3) and iii (u4-u7) include transgressive and highstand (regressive) systems tracts. transgressive tracts are specifi c in being represented by lacustrine deposits. falling-stage sediments have not been identifi ed, and the entire sedimentary successions originated during relative sea-level rise. the pb of mtp represents an example of sedimentary and sequence evolution at a deforming foreland basin margin. the evolution of this margin is characterised by structural and stratigraphic complexities which include growth strata, angular unconformities, syndepositional folding, intraformational faulting and uplift, alluvial and marine onlaps onto deformed basement, and tectonically induced, proximal-distal variations in facies and sediment thickness. the origin of lacustrine transgressive tracts may have been related to the backtilting of the proximal part of the basin. figure 28: view towards the n looking upon the se (left) and s (right) slopes of northeastern mtp. cretaceous basement and fossil-rich limestones (u5a) in the lower right constitute a smaller anticline inclined s, towards the viewer, and gently plunging left (w, into the mountain). two gullies in the middle show mudstone-dominated shelf deposits (u5), which were involved in the folding in their lower part. g, gilbert delta; highest wall (15 m) shows foresets steeply inclined towards the left (ssw). u6 (upper lacustrine unit) has not been clearly identifi ed in this area. unconformity in the upper right is restricted to this proximal area, where it cuts previously deformed units, and was later involved in deformation. logs k and l are shown in fig. 6. see also fig. 26. for further explanation see text. zupanič and babić: sedimentary evolution of an inner foreland basin margin: palaeogene promina beds of the type area, mt. promina... geologia croatica 117 among three principal factors which control the history of a basin infi lling, i.e. supply, subsidence and eustasy (galloway, 1989), we suggest that there was no single factor which would have been dominant throughout the entire sedimentary evolution. the majority of the regressive trends were presumably dominated by high sediment supply which was a direct response to near-continuous loading and orogen erosion. the origin of one regressive segment might have been mainly infl uenced by a combination of subsidence and sediment supply. the principal factor for transgressive trends was presumably subsidence, related to tectonic pulses. the overall dominance of tectonism in shaping depositional styles, sequence development and distribution of sediments was related to sedimentary evolution within deforming, marginal parts of the foreland basin which was situated in close proximity to and infl uenced by the main, active dinaric thrust units. acknowledgement this work is part of the project “evolutionary changes of the dinarides from subduction to modern adriatic beaches” supported by ministry of science, education, and sport of the republic of croatia. comments by reinhard roetzel (geological survey of austria) and aleksander horvat (university of ljubljana) helped in improving the paper. we thank m.sc. m. hernitz-kučenjak (ina, zagreb) for her help in making the microphotographs, and mr. r. košćal (institut of geology and paleontology, faculty of science, zagreb) for the artwork. dr. b. lužar-oberiter and dr. j. robson kindly corrected the english text. references allen, p.a., crampton, s.l. & sinclair, h.d. (1991): the inception and early evolution of the north alpine foreland basin, switzer land.− basin res., 3, 143−163. anadón, p. & zamarreňo, i. (1981): paleogene nonmarine algal deposits of the ebro basin, northeastern spain.− in: monty, c. (ed.): phanerozoic stromatolites. springer, berlin, 140−154. babić, lj. & zupanič, j. (1985): promina-naslage sjeverne dalmacije: raznolikost sedimentacijskih okoliša i litostratigrafska nomenklatura.− geol. glasnik, 28, sarajevo, 139−141. babić, lj. & zupanič, j. (1990): progradacijski slijedovi u paleogenskom klastičnom bazenu vanjskih dinarida, od sjeverne dalmacije do zapadne hercegovine.− rad jugoslavenske akademije, 449, 319−343. (in croatian, english summary). babić, lj. & zupanič, j. (2007): major events and stages in the sedimentary evolution of the paleogene promina basin (dinarides, croa tia).− nat. croat., 16/4, 215−232. babić, lj. & zupanič, j. (2008): evolution of a river-fed foreland basin fi ll: the north dalmatian fl ysch revisited (eocene, outer dinarides).− nat. croat., 17/4, 357−374. babić, lj., zupanič, j. & kurtanjek, d. (1995): sharply-topped alluvial gravel sheets in the palaeogene promina basin (dinarides, croatia).− geol. croat., 48/1, 33−48. burns, b.a., heller, p.l., marzo, m. & paola, c. (1997): fluvial response in a sequence stratigraphic framework: example from the montserrat fan delta, spain.− j. sediment. res., 67/2, 311−321. catuneanu, o. (2006): principles of sequence stratigraphy.− elsevier, amsterdam, 375 p. chorowicz, j. (1977): étude géologique des dinarides le long de la transversale split-karlovac (yougoslavie).− soc. géol. nord, publ. 1, villeneuve d’asq, 331 p. chough, s.k., hwang, i.g. & choe, m.y. (1990): the miocene doumsan fan-delta, southeast korea: a composite fan-delta system in back-arc margin.− j. sediment. petrol., 60/3, 445−455. colella, a. (1988): pliocene-holocene fan deltas in the crati basin, southern italy: a consequence of varying tectonic conditions.− in: nemec, w. & steel, r.j. (eds.): fan deltas: sedimentology and tectonic settings. blackie, glasgow, 50−74. collinson, j.d. (1996): alluvial sediments.− in: reading, h.g. (ed.): sedimentary environments. 3. ed. blackwell, oxford, 37−82. crampton, s.l. & allen, p.a. (1995): recognition of forebulge unconformities associated with early stage foreland basin development: example from the north alpine foreland basin.− am. assoc. petr. geol. b., 79/10, 1495−1514. dorsey, r.j., umhoefer, p.j. & renne, p.r. (1995): rapid subsidence and stacked gilbert-type fan deltas, pliocene loreto basin, baja california sur, mexico.− sediment. geol., 98, 181−204. dorsey, r.j., umhoefer, p.j. & falk, p.d. (1997): earthquake clustering inferred from pliocene gilbert-type fan deltas in the loreto basin, baja california sur, mexico.− geology, 25/8, 679−682. embry, a.f. & johannessen, e.p. (1992): t-r sequence stratigraphy, facies analysis and reservoir distribution in the uppermost triassic-lower jurassic succession, western sverdrup basin, arctic canada.− in: vorren, t.o., bergsager, e., dahl-stamnes, o.a., holter, e., johansen, b., lie, e. & lund, t.b. (eds.): arctic geology and petroleum potential. norw. petrol. soc. spec. publ., 2, 121−146. embry, a.f. (2002): transgressive-regressive (t-r) sequence stratigraphy.− in: armentrout, j.m. & rosen, n.c. (eds.): sequen ce stratigraphic models for exploration and production: evolving methodology, emerging models and application histories. 22. ann. gulf coast sect. sepm foundation bob f. perkins res. conf., conf. proc., 151−172. ethridge, f.g. & wescott, w.a. (1984): tectonic setting, recognition and hydrocarbon reservoir potential of fan delta deposits.− in: koster, e.h. & steel, r.j. (eds.): sedimentology of gravels and conglomerates. can. soc. petroleum geol. mem., 10, cal gary, 217−235. flemings, p.b. & jordan, t.e. (1989): a synthetic stratigraphic model of foreland basin development.− j. geophys. res., 94 (b4), 3851−3866. ford, m., williams, e.a., artoni, a., verges, j. & hardy, s. (1997): progressive evolution of fault-related fold pair from growth strata geomteries, sant llorenc de morunys, se pyrenees.− j. struct. geol., 19/3−4, 413−441. gawthorpe, r.l. & colella, a. (1990): tectonic controls on coarse-grained delta depositional system in rift basins.− in: colella, a. & prior, d.b. (eds.): coarse-grained deltas. int. assoc. sediment. spec. publ., 10, blackwell, oxford, 113−127. galloway, w.e. (1989): genetic stratigraphic sequences in basin analysis i: architecture and genesis of fl ooding-surface bounded depositional units.− am. assoc. petrol. geol. b., 73/2, 125−142. gilbert, g.k. (1885): the topographic features of lake shores.− ann. rep. u.s. geol. surv., 5, 75−123. hedberg, h.d. (1976): international stratigraphic guide.− willey, new york, 200 p. helland-hansen, w. & martinsen, o.j. (1996): shoreline trajectories and sequences: description of variable depositional-dip scenarios.− j. sediment. res., 66/4, 670−688. heller, p.l., angevine, c.l. & winslow, n.s. (1988): two-phase stratigraphic model of foreland basin sequences.− geology, 16/6, 501−504. herak, m. & bahun, s. (1979): the role of calcareous breccia (jelar formation) in the tectonic interpretation of the high karst zone of the dinarides.− geol. vjesnik, 31, 49−59. geologia croatica 64/2geologia croatica 118 hunt, d. & tucker, m.e. (1992): stranded parasequences and the forced regressive wedge systems tract: deposition during base-level fall.− sediment. geol., 81/1, 1−9. ivanović, a., sikirica, v., marković, s. & sakač, k. (1977): osnovna geološka karta sfrj 1:100000, list drniš [basic geological map of sfry 1:100000, drniš sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd. ivanović, a., sikirica, v. & sakač, k. (1978): osnovna geološka karta sfrj 1:100000, tumač za list drniš [basic geological map of sfry 1:100000, geology of the drniš sheet − in croatian, english abstr.].− geološki zavod, zagreb, savezni geološki zavod, beograd, 59 p. kerner, f. v. (1894): ueber die geologischen verhältnisse der gegend von dernis in dalmatien.− verhandlungen der geologischen reichsanstalt, 1894/2, 75−81. kerner, f.v. (1896): geologische specialkarte der oesterr.-ungar. monarchie, 1:75.000. kistanje und drniš.− geol. reichsanst., wien. kerner, f. v. (1901): erläuterungen zur geologischen karte der oesterr.-ungar. monarchie. kistanje-dernis, 1:75.000.− geol. reichsanst., wien, 40 p. korbar, t. (2009): orogenic evolution of the external dinarides in the ne adriatic region: a model constrained by tectonostratigraphy of upper cretaceous to paleogene carbonates.− earth-science reviews (2009) doi: 10.1016/.earscirev.2009.07.004, 1−17. kühn, o. (1946): das alter der prominaschichten und der innereozänen gebirgsbildung.− jahrbuch der geologischen bundesanstalt, 91/1−2, 49−94. lopez-blanco, m., marzo, m. & piňa, j. (2000): transgressiveregressive sequence hierarchy of foreland, fan-delta clastic wedges (montserrat and sant llorenç del munt, middle eocene, ebro basin, ne spain).− sediment. geol., 138, 41−69. mamužić, p. (1975): osnovna geološka karta jugoslavije 1:100000, tumač za list šibenik [basic geological map of sfry 1:100000, geology of the šibenik sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd, 37 p. marinčić, s. (1981): eocenski fl iš jadranskog pojasa.− geol. vjesnik, 34, 27−38. marković, s. (2002): hrvatske mineralne sirovine.− institut za geološka istraživanja, zagreb, 544 p. marzo, m. & steel, r. (2000): unusual features of sediment supplydominated, transgressive-regressive sequences: paleogene clastic wedges, se pyrenean foreland basin, spain.− sediment. geol., 138, 3−15. massari, f. & colella, a. (1988): evolution and types of fan-delta systems in some major tectonic settings.− in: nemec, w. & steel, r.j. (eds.): fan deltas: sedimentology and tectonic settings. blackie, glasgow, 103−122. massari, f. & parea, g.c. (1988): progradational gravel beach sequences in a moderateto high-energy, microtidal marine environment.− sedimentology, 35, 881−913. miall, a.d. (1978): tectonic setting and syndepositional deformation of molasse and other nonmarine-paralic sedimentary basins.− can. j. earth sci., 15, 1613−1632. miall, a.d. (1996): the geology of fluvial deposits.− springer, berlin, 582 p. mikes, t., báldi-beke, m., kázmér, m., dunkl, i. & von eynat ten, h. (2008): calcareous nannofossil age constraints on miocene fl ysch sedimentation in the outer dinarides (slovenia, croa tia, bosnia-herzegovina and montenegro).− in: siegesmund, s., fügenschuh, b. & froitzheim, n. (eds.): tectonic aspects of the alpine-dinaride-carpathian system. geol. soc. spec. publ., 298, london, 335−363. mrinjek, e. (2008): excursion 3a, split-rab, promina beds in canyon of krka river and bribirske mostine.− in: marjanac, m. (ed.): 5. int. progeo symp. conserv. geol. heritage. rab, guideb. progeo croatia, zagreb, 37−77. mrinjek, e. & pencinger, v. (2008): excursion 3b, rab-split, the benkovac stone a building stone from the promina beds: a late eocene succession of storm-dominated shelf deposits with highly diverse trace fossils.− in: marjanac, m. (ed.): 5. int. progeo symp. conserv. geol. heritage. rab, guideb. progeo croatia, zagreb, 105−125. nemec, w. (1990): aspects of sediment movement on steep delta slopes.− in: colella, a. & prior, d.b. (eds.): coarse-grained del tas. int. assoc. sediment. spec. publ. 10, blackwell, oxford, 29−73. nikler, l. (1982): značaj i karakteristike smeđih ugljena dalmacije.− geol. vjesnik, 35, 181−194. north american commission on stratigraphic nomen clature (nacsn) (1983): north american stratigraphic code.− am. assoc. petrol. geol. bull., 67, 841−875. posamentier, h.w. & vail, p.r. (1988): eustatic controls on clastic deposition ii sequence and systems tract models.− in: wilgus, c.k., hastings, b.s., kendall, c. g. st. c., posamentier, h.w., ross, c.a. & van wagoner, j.c. (eds.): sea-level changes: an integrated approach. sepm, spec. publ. 42, tulsa, 125−154. posamentier, h.w. & allen, g.p. (1993): sliciclastic sequence stratigraphic patterns in foreland ramp-type basins.− geology, 21/5, 455−458. posamentier, h.w. & allen, g.p. (1999): siliciclastic sequence stratigraphy-concepts and applications.− sepm concepts in sedimentology and palaeontology, 7/5, tulsa, 204 p. postma, g. (1990): depositional architecture and facies of river and fan deltas: a synthesis.− in: colella, a. & prior, d.b. (eds.): coarse-grained deltas. int. assoc. sediment. spec. publ. 10, blackwell, oxford, 13−27. postma, g. (1995): sea-level-related architectural trends in coarsegrained delta complexes.− sediment. geol., 98/1, 3−12. postma, g. & roep, t.b. (1985): resedimented conglomerates in the bottomsets of gilbert-type gravel deltas.− j. sediment. petrol., 55/6, 874−885. postma, g. & cruickshank, c. (1988): sedimentology of the late weichselian to holocene, terraced fan delta, varangerfjord, northern norway.− in: nemec, w. & steel, r.j. (eds.): fan deltas: sedimentology and tectonic settings. blackie, glasgow, 144−157. postma, g., babić, lj., zupanič, j. & roe, s-l. (1988): deltafront failure and associated bottomset deformation in a marine, gravelly gilbert-type fan delta.− in: nemec, w. & steel, r.j. (eds.): fan deltas: sedimentology and tectonic settings. blackie, glasgow, 91−102. prelogović, e., pribičević, b., ivković, ž., dragičević, i., buljan, r. & tomljenović, b. (2003): recent structural fabric of the dinarides and tectonically active zones important for petroleum-geological exploration in croatia.− nafta, 55/4, 155−161. prior, d.b. & bornhold, b.d. (1990): the underwater development of holocene fan deltas.− in: colella, a., prior, d.b., (eds.): coarse-grained deltas. int. assoc. sediment. spec. publ. 10, blackwell, oxford, 75−90. quitzow, h.w. (1941): stratigraphisch-tektonische untersuchungen im norddalmatinischen alttertiär.− jahrbuch der reichsstelle für bodenforschung, 62, 422−437. riba, o. (1976): syntectonic unconformities of the alto cardener, spa nish pyrenees: a genetic interpretation.− sediment. geol., 15/3, 213−233. sakač, k., benić, j., bahun, s. & pencinger, v. (1993): stratigraphic and tectonic position of paleogene jelar beds in the outer dinarides.− nat. croat., 2/1, 55−72. shanley, k.w. & mccabe, p.m. (1994): perspectives on sequence stratigraphy of continental strata. am. assoc. petrol. geol. b., 78/4, 544−568. tucker, m.e. (2001): sedimentary petrology. an introduction to the origin of sedimentary rocks. 3. ed.− blackwell, oxford, 262 p. tucker, m.e. & wright, v.p. (1990): carbonate sedimentology.− blackwell, oxford, 496 p. zupanič and babić: sedimentary evolution of an inner foreland basin margin: palaeogene promina beds of the type area, mt. promina... geologia croatica 119 vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.− palaeogeogr., palaeoclimatol., palaeoecol., 220/3−4, 333−360. zupanič, j. (1969): promina naslage planine promine.− geol. vjesnik, 22, 477−498. zupanič, j., babič, l., roe, s.l. & postma, g. (1987): wave-cut platform and wave-built terrace succeeding a gilbert delta.− abstracts, int. symp. fan-deltas, sedimentology and tectonic settings. univ. bergen, bergen, norway, 1987, p. 48. zupanic, j., babic, l., roe, s.l. & postma, g. (1988): construction and destruction of gilbert-type deltas during transgression. an example from the eocene promina formation, yugoslavia.− abstracts int. workshop fan deltas, univ. calabria, calabria, 1988, 58−59. appendix: formal stratigraphic names? 1. lithostratigraphy as the pb of the entire north dalmatian foreland basin includes a variety of sedimentary units, the pb has been proposed to be designated as a group (babić & zupanič, 1985), i.e. the promina group, if formal lithostratigraphic naming (hedberg, 1976; nacsn, 1983) is applied. following the same rules, the fi rst lower-rank units, i.e. those presented in this work from the type locality of the promina beds, may be treated as formations. namely, they have been adequately described using their lithology, boundaries, stratigraphic position, age (kühn, 1946), areal distribution, mappability and reference sections (stratotypes). the latter are represented by the relevant segments of logs (figs. 6, 7) located closest to the localities (fig. 5) which are given below as the fi rst part of the names of the relevant formations. so called supplementary sections of some of these formations are located laterally (fig. 5). most of these units coincide with those previously separated in both mtp and other parts of the north dalmatian foreland basin (babić et al., 1995; babić & zupanič, 2007 with references). the poorly known u6 was not given a name. lithostratigraphic names would be as follows: kalun conglomerate (u1; basal alluvium) varoš formation (u2; lower lacustrine unit) knezovi conglomerate (u3; lagoon to alluvium) počivalica formation (u4; middle lacustrine unit) previje formation (u5; shelf/delta alternation) bukovac limestone (u5a; fossil-rich limestone) unnamed formation (u6; upper lacustrine unit) čavnovka conglomerate (u7; terminal alluvium) 2. allostratigraphy as the units described in this work are defi ned and identifi ed on the basis of laterally traceable bounding discontinuities, other attributes being the same as for the formations cited above, these units are materially identical to allostratigraphic units introduced by nacsn (1983). genetic interpretations are not obligatory for defi ning allostratigraphic units, however, such interpretations may infl uence the choice of their boundaries (nascn, 1983, article 58, remark (f)). the units identifi ed here are defi ned on the basis of their genesis. their bounding surfaces are prominent, well defi ned genetically and their types are restricted to specifi c kinds of changes across them. hence, these units are not poorly defi ned in con trast to the wide defi nition of changes which are possible across the bounding discontinuities using the code of nacsn (1983) (see relevant comments by posamnatier & allen, 1999 and catuneanu, 2006). the rules for naming allostratigraphic units are the same as those for naming lithostratigraphic units (nacsn, 1983). thus, the names for the units in mtp, which would constitute the promina allogroup, may be as follows: kalun conglomerate alloformation (u1; basal alluvium) varoš alloformation (u2; lower lacustrine unit) knezovi conglomerate alloformation (u3; lagoon to alluvium) počivalica alloformation (u4; middle lacustrine unit) previje alloformation (u5; shelf/delta alternation) bukovac limestone alloformation (u5a; fossil-rich limestone) unnamed alloformation (u6; upper lacustrine unit) čavnovka conglomerate alloformation (u7; terminal alluvium) 3. subdivision and naming of units of the promina beds: a comparison the lithostratigraphic subdivision may be useful, as generally confi rmed by its widespread use. the allostratigraphic subdivision, using specifi c types of bounding discontinuities, may be regarded as more natural, as well as more appropriate for interpretative purposes, because it uses important, na tural attributes. in fact, the two classifi cations, if applied to successions described here, differ in formal naming, not in material facts, and the choice between them does not seem to be of paramount importance and primary interest. however, it is believed that the classifi cation and names used here (most of the relevant units have been separated and defi ned in a similar way previously (babić et al., 1995; babić & zupanič, 2007); see also fig. 4) are more suited for communication and study of relevant geological objects and geological evolution, as they convey more relevant information in accordance with the present level of research and practical needs. manuscript received october 22, 2010 revised manuscript accepted february 24, 2011 available online june 09, 2011 geologia croatica 64/2geologia croatica 120 1. introduction early–middle pennsylvanian (late carboniferous) age coalbearing strata in europe can be found in two general depositional settings (opluštil & cleal, 2007; cleal et al., 2010, 2011). the most extensive deposits were formed in paralic settings, most notably on the variscan foreland and associated basins between the british isles and northern turkey, in the donets basin of eastern europe, and the cantabrian basin of the iberian peninsula. together, these basins cover an area of up to 9 x105 km2 (cleal & thomas, 2005). in addition there are several intramontane basins associated with the variscan mountains, such as saar-lorraine (france and germany), west and central bohemia (czech republic), svoge (bulgaria) and the stephanian basins of southern france. although much smaller than the paralic basins, they are of interest because of what they tell us about the evolution of the variscan mountains and the distinctive fossil biotas that they yield, especially the macrofloras, which probably reflect at least in part their relatively high elevation during pennsylvanian times. there is evidence of at least two such pennsylvanianage intramontane basins in the south carpathians in romania, the reşiţa basin within the getic nappe and the sirinia basin in the western upper danubian realm (danubian units). neither is particularly well exposed and what coal mining did occur there has now ceased. nevertheless, both have yielded fossil biotas which are of biostratigraphical and palaeobiogeographical interest (see dragastan et al., 1997 and popa, 2005 for historical reviews). in the present paper we document macrofloras from the sirinia basin found at baia nouă (also known in the czech language as nové doly) located in the dubova commune, mehedinţi county, in the central area of the iron gates natural park, the largest natural park in romania. ab stra ct the cucuiova formation is a pennsylvanian (late carboniferous) coal-bearing unit in the intramontane sirinia basin, which was formed in the danubian units of the south carpathians. the main coal seam in the cucuiova formation was worked at baia nouă (nové doly) and this locality has yielded a typical adpression coal flora. previous studies have suggested that this flora was moscovian (late westphalian or even earliest stephanian) in age. however, newly collected samples from baia nouă have included abundant neuralethopteris, which clearly indicates a late bashkirian (langsettian) age. this suggests a possible link with the svoge basin in northern bulgaria, which is another intramontane basin located on the balkan terrane with early westphalian coal-bearing deposits. keywords: pennsylvanian, palaeobotany, romania, biostratigraphy, palaeogeography  geologia croatica 65/3 329–343 1 figs. 2 tabs. 4 pls. zagreb 2012 geologia croaticageologia croatica aspects of romanian palaeozoic palaeobotany and palynology. part iii. the late carboniferous flora of baia nouă, sirinia basin  mihai e. popa1 & christopher j. cleal 2 1 university of bucharest, faculty of geology and geophysics, laboratory of palaeontology, 1, n. balcescu ave., 010041, bucharest, romania; (mihai@mepopa.com) 2 department of biodiversity & systematic biology, national museum wales, cathays park, cardiff cf10 3np, uk; (chris.cleal@museumwales.ac.uk) doi: 104154/gc.2012.22 geologia croatica 65/3geologia croatica 330 2. geological context baia nouă is a small coal mining locality in the southern part of the almăj mountains in the south carpathians (text-fig. 1a, b). it occurs in the southern part of the sirinia basin, a sedimentary area also variously known as the sviniţa zone (răileanu et al., 1963), the sviniţa – svinecea mare sedimentary zone (năstăseanu, 1984; năstăseanu et al., 1981), or the sviniţa – faţa mare zone (răileanu, 1953, 1960). it is the westernmost sedimentary area of the upper (internal) danubian units (codarcea, 1940, răileanu, 1953; berza et al., 1983), an important tectonic part of the south carpathian chain. the upper danubian units correspond to the upper danubian depositional realm, which includes a western molasse basin (the sirinia basin, including both pennsylvanian and cisuralian sediments) and an eastern molasse basin (the presacina basin, including cisuralian sediments), separated by a ridge (the iablaniţa-rudăria ridge). the sirinia sedimentary zone includes upper palaeozoic (pennsylvanian – cisuralian, confined to the palaeozoic sirinia basin sensu-strictum) and mesozoic (lower jurassic – cretaceous) sediments. the upper palaeozoic deposits were considered to be the variscan molasse of the danubian units (răileanu, 1953, năstăseanu et al., 1973, năstăseanu, 1987) and consist of the pennsylvanian (upper carboniferous) cucuiova formation (text-fig. 1c) overlain by the cisuralian (lower permian) povalina and trescovăţ formations (stănoiu & stan, 1986). the permian formations were reinterpreted by a. seghedi et al. (1999) and i. seghedi (2010), the latter author defining the pyroclastic sequences interbedded with terrigeous sequences as the result of subaequous lacustrine eruptions passing to subaerial volcanism. the cucuiova formation (stănoiu & stan, 1986) consists of sandstones, mudstones and one or two coal seams (text-fig. 1c), with local basic lava flows. the main coal seam is a metamorphosed bituminous coal, and varies in thickness between 1m and 15m (mateescu, 1964) due to strong alpine deformation that affected the variscan molasse. the cucuiova formation is best exposed near baia nouă due to extensive mining works, although outcrops (now covered) have also been described around the cucuiova hill (locus typicus) and along the povalina valley, the dragosela valley (outcrops and exploration galleries) and the cameniţa valley (text-fig. 1b). a review of the outcrops, microand macrofloral contents, ages of sequences and ranges was published by popa (2005). figure 1: a. location of the baia nouă area in south-western romania. the marked rectangle represents the area shown in fig. 1b. b. occurrence of carboniferous fossil plant localities in the sirinia basin (underlined names), and the distribution of the cucuiova formation (grey shading), within the tectonic boundaries of the upper danubian unit. c. lithostratigraphical log of the carboniferous cucuiova formation, here dated as langsettian – westphalian d, previously considered in popa (2005) as bolsovian – westphalian d. all redrawn from popa (2005). mihai e. popa & christopher j. cleal: aspects of romanian palaeozoic palaeobotany and palynology. part iii. the late carboniferous ... geologia croatica 331 ta bl e 1: t ax a pr ev io us ly p ub lis he d (a nd h er e up da te d fro m a n om en cl at ur al p oi nt o f v ie w ) f ro m b ai a n ou ă, m ar ke d w ith * if th e ta xo n w as o nl y ci te d, a nd w ith * * if th e ta xo n w as c ite d an d al so il lu st ra te d. t hi s on ly in cl ud es p ap er s p ro vi di ng n ew re su lts a nd n ot th os e m er el y qu ot in g th e w or k of o th er s. st u r (1 87 0) sc h a fa rz ik (1 89 4) ră il ea n u (1 95 3) bi țo ia n u (1 97 2a ) bi țo ia n u (1 97 2b ) bi țo ia n u (1 97 3) bi țo ia n u (1 97 4) bi țo ia n u (1 98 7) al et ho pt er is lo nc hi tic a ** a. se rli * * al lo io pt er is co ra llo id es * ** an nu la ria cf . r ad ia ta * as ol an us ca m pt ot ae ni a ** ** ** * as te ro ph yl lit es lo ng ifo liu s ** * * * ca la m ite s c ar in at us ** ** ** * c. ci st i * * * ** * * c. su ck ow i ** ** ca la m os ta ch ys g er m an ic a * ca rd io ca rp us g ut bi er i ** le pi do de nd ro n ac ut um * ** ** l. o bo va tu m ** ** * l. o ph iu ru s ** le pi do de nd ro n sp . * le pi do st ro bu s s p. ** ** m ar io pt er is hi rs ut a ** * ** * m . m ic ro -s au ve ur i ** m . n er vo sa ** ** * m . s au ve ur i ** ** ** * m ar io pt er is sp . ** ** n eu ra le th op te ris sc hl eh an i ** * * n eu ro pt er is ar be ri * n . a tt en ua ta ** n . c f. ar be ri ** n . c f. ob liq ua ** n . g ig an te a * n . o va ta ** ** n eu ro pt er is sp . * n . t en ui fo lia ** * * * pa la eo st ac hy a pe du nc ul at a ** * geologia croatica 65/3geologia croatica 332 bituminous coals were first discovered here in 1840 and have been extracted since 1874 (răileanu et al., 1963); mining activities in baia nouă ended in 2006 for safety and financial reasons. geological studies in the area date back to the second half of the 19th century (tietze, 1872; hantken, 1878; schafarzik, 1894). mateescu (1964) described the petrography of the baia nouă coals, reporting various types of plant and fungal remains ranging from xylem tissues in fusinite, sporinite, resinite, and sclerotinite. the petrography of coals including sclerotinite from the cucuiova formation exposed in the dragosela valley was described by ilie &biţoianu (1966) and biţoianu & ilie (1968). 3. previous palaeobotanical studies the first palaeobotanical data dealing with baia nouă were published by stur (1870; also quoted by tietze, 1872 and hantken, 1878), citing the identifications by constantin von ettingshausen, and by schafarzik (1894), but no specimens were illustrated. in more modern times, the main palaeobotanical studies on baia nouă were undertaken by semaka (1962, 1970) and biţoianu (1972a, b, 1973, 1974, 1987). geological studies by răileanu (1953, 1960) also included new palaeobotanical data. these studies, which were concerned with biostratigraphy and sometimes (biţoianu, 1987) palaeoecology, and mainly comprise just species lists although in a few cases specimens were illustrated. other plant fossils from the cucuiova formation were recorded by maxim (1967, 1969) from the cucuiova hill area (along an un-named tributary of the povalina valley, south of baia nouă) and from the dragosela valley (biţoianu, 1972a, b, 1973, 1974). dragastan et al. (1997) and popa (2005) summarised the information then available. the identifications provided in the most important of these previous studies are summarised in table 1. 4. materials and methods as pointed out by popa (2005) previously published palaeobotanical data from baia nouă are mostly not supported today by collections, with the exception of one hand specimen in the s. cotuţiu collection (national geological museum, geological institute of romania, bucharest), two samples in the c. eufrosin collection and one sample in the i.z. barbu collection (both in the historical collections of the laboratory of palaeontology, university of bucharest). further study of the baia nouă flora must therefore be based on freshly collected material. due to the tectonic evolution of the sirinia basin, plant fossils from baia nouă are exclusively adpressions (i.e. compression/impressions – see shute & cleal, 1986) that lack cuticles or in situ spores. st u r (1 87 0) sc h a fa rz ik (1 89 4) ră il ea n u (1 95 3) bi țo ia n u (1 97 2a ) bi țo ia n u (1 97 2b ) bi țo ia n u (1 97 3) bi țo ia n u (1 97 4) bi țo ia n u (1 98 7) pe co pt er is m ilt on i ** * * * p. ra co ne ns is ** p. sa ra ef ol ia ** * * se nf te nb er gi a pl um os ade nt at a * ** s. p lu m os ade nt at a va r. de lic at ul a ** si gi lla ria p ol yp lo ca * ** ** ** * * si gi lla ria sp . * * ** s. te ss el at a * * ** ** * sp he no ph yl lu m cu ne ifo liu m ** * ** * sp he no pt er is an dr ae an a * s. h er ba ce a * s. o bt us ilo ba * s. sp in ifo rm is * s. st on eh ou se i * st ig m ar ia fi co id es * * * ** * * tr ig on oc ar pu s s p. * ta bl e 1: c on tin ue d. mihai e. popa & christopher j. cleal: aspects of romanian palaeozoic palaeobotany and palynology. part iii. the late carboniferous ... geologia croatica 333 plate 1 1 calamites carinatus, p41/c5/3, fragment 1, m.e. popa collection, university of bucharest. scale bar: 10mm. 2 calamites carinatus, p41/c5/2, fragment 1, m.e. popa collection, university of bucharest. scale bar: 10mm. 3 sphenophyllum cuneifolium, sample 0512, c. eufrosin collection, university of bucharest. scale bar: 10mm. 4 sphenophyllum cuneifolium, sample 0512, c. eufrosin collection, university of bucharest. scale bar: 10mm. 5 sphenophyllum cuneifolium, sample 0512, c. eufrosin collection, university of bucharest. scale bar: 1mm. geologia croatica 65/3geologia croatica 334 plant fossils tend to be relatively rare here, the m.e. popa collection comprising just 65 hand specimens collected since 1996 from the sterile dump of the former mine; these specimens are now curated at the laboratory of palaeontology, university of bucharest. in addition, in 2011 a silicified wood fragment was collected from the same sterile dump and is the subject of a separate study. the fossils were recorded as separate, individual fragments belonging to hand specimens, according to the standard detailed by popa (2011). the lithological context of the fossils is represented by dark, fine, coalified sandstones and mudstones. paleosoils are frequent, samples which can be interpreted as belonging to stigmarian root horizons. the fossils were photographed using a panasonic dmcl10 digital camera with an olympus 35mm zuiko macro lens and a kaiser copy-stand with two ikea fluorescent lateral lights. for close-up work, a carl zeiss stemi gzs dissecting microscope was used, to which a canon powershot a640 digital camera is attached. digital images taken with the dissecting microscope were enhanced using the carl zeiss axiovision extended focus software for increasing the depth of focus, and archived with the carl zeiss asset archive software. 5. systematics this is not intended as a detailed systematic analysis of these species, and the synonyms quoted below are merely the records of publication of the basionym, the most important combinations of the basionym, and any specimens that have been previously illustrated from the cucuiova formation. since none of the specimens preserve anatomy or reproductive structures we have made no attempt to place them in suprageneric taxa other than classes. class sphenopsida genus calamites sternberg, 1820 calamites carinatus sternberg, 1823 (pl. 1, figs. 1, 2) 1823 calamites carinatus – sternberg, 1823, p. 39, pl. 32, fig. 1 1972a calamites carinatus – biţoianu, p. 394, pl. 2, fig. 1 1972b calamites carinatus – biţoianu, p. 126, 127, pl. 1, fig. 5 1973 calamites carinatus – biţoianu, p. 116, pl. 1, fig. 3 material: several fragments of this species are preserved on samples p41/c5/3 (pl. 1, fig. 1) and p41/c5/2 (pl. 1, fig. 2). description: articulated, flattened stems with typical longitudinal ribs and internodes longer than broad (pl. 1, figs. 1, 2). internodes width 20–40 mm, longitudinal rib density 9–11 per cm. all stems show nodal branch scars which suggest an opposite pair arrangement. the scars have ribs converging towards them, as well as convergent ribs within the scars themselves (pl. 1, fig. 2). remarks: the collected material consists of stems with oppositely arranged nodal branch scars and converging ribs typical of calamites carinatus. this species was previous recorded from romania by biţoianu (1972 a, b, 1973, 1974), only from baia nouă, where it was considered westphalian d (asturian) in age. elsewhere it has a stratigraphical range throughout the westphalian stage (e.g. crookall, 1969; josten, 1991). genus sphenophyllum brongniart sphenophyllum cuneifolium (sternberg) zeiller, 1879 (pl. 1, figs. 3–5) 1821 rotularia cuneifolia – sternberg, p. 33, pl. 26, figs 4ab 1879 sphenophyllum cuneifolium – zeiller, p. 30 1972a sphenophyllum cuneifolium – biţoianu, p. 126, pl. 2, fig. 11 1973 sphenophyllum cuneifolium – biţoianu, p. 116, pl. 2, fig. 15 material: specimen 0512 of the c. eufrosin collection (laboratory of palaeontology, university of bucharest) is littered with sphenophyllum cuneifolium leaves and branches. description: internodes 10–25 mm long and 2–6 mm wide, striated longitudinally, and slightly expanded at the nodes. at the nodes are whorls of 6–10 deltoidal, elongated, triangular leaves, 9–13 mm, rarely 14 mm long and 3–5 m, rarely 7 mm wide at the apex (pl. 1, fig. 3). all leaves of the whorl are equal in length. lateral margins are straight; the distal margin is straight or slightly rounded, with 12–18 sharp, equal, triangular and symmetrical teeth (pl. 1, figs. 4, 5). from the base of the leaf, a single vein divides dichotomously several times to the apex, where each tooth receives a single vein (pl. 1, fig. 5). remarks: the baia nouă material is typical for sphenophyllum cuneifolium in the shape of the leaves, the apex and the symmetrical, sharp distal teeth. josten (1983, 1991) described sphenophyllum cuneifolium from nw germany with similar sized leaves to those from baia nouă, but those from the british isles figured by crookall (1929) and cleal & thomas (1994) tended to be rather smaller, typically no more than 12 mm long. the romanian sphenophyllum cuneifolium is similar in size to sphenophyllum majus (bronn) bronn, but does not have the deeply sinused apex that s. majus typically has. also, the leaves have affinities with sphenophyllum emarginatum with respect to the slightly curved shape of their distal margins, but they have pointed teeth with straight or convex dental margins. the records of sphenophyllum cuneifolium from baia nouă by biţoianu (1972a, 1972b, 1973) were not accompanied by descriptions and the poor illustrations are difficult to assess. biţoianu (1972a, 1973) considered sphenophyllum cuneifolium to be a characteristic species for the bolsovian – westphalian d interval in the sirinia basin but elsewhere it ranges between the kinderscoutian and asturian substages (e.g. josten, 1983, 1991; cleal, 2005, 2007). mihai e. popa & christopher j. cleal: aspects of romanian palaeozoic palaeobotany and palynology. part iii. the late carboniferous ... geologia croatica 335 plate 2 1 stigmaria ficoides, p41/c5/1, fragment 1, m.e. popa collection, university of bucharest. scale bar: 10mm. 2 sigillaria sp. sample 0558, fragment 1, i.z. barbu collection. scale bar: 10mm. geologia croatica 65/3geologia croatica 336 class lycopsida genus stigmaria brongniart, 1822 stigmaria ficoides (sternberg) brongniart, 1822 (pl. 2, fig. 1) 1820 variolaria ficoides – sternberg, p. 24, pl. 12 1822 stigmaria ficoides – brongniart, p. 228. 1972a stigmaria ficoides – biţoianu, p. 126, pl. 2, fig. 9 material: casts of this fossil-species are abundant in the newly collected samples from baia nouă, such as fragment 1 of sample p51/c5/1 (pl. 2, fig. 1) in the m.e. popa collection (university of bucharest). description: rhizophore fragments of lycopsids, represented by fragments of flattened, cylindrical casts with circular, regularly distributed scars to which roots are often attached (pl. 2, fig. 1). remarks: stigmaria ficoides has been cited from romania both from the reşiţa and from the sirinia basins. in both basins, the material is recorded in situ, with rootlets still attached. as a rhizophore, it could belong to any one of several lycopsid genera. maxim (1967) also cited stigmaria rugulosa gothan from here but this almost certainly just refers to specimens of s. ficoides. genus sigillaria brongniart, 1822 sigillaria tesselata brongniart, 1837 (pl. 3, fig. 1) 1837 sigillaria tesselata – brongniart, p. 436, pl. 162, figs. 1–4 material: the only known example from baia nouă is specimen no. 174 in the s. cotuţiu collection (national geological museum, bucharest). description: the leaf scars are regular, 7–8 mm in outline diameter, somewhat rounded rather hexagonal in shape, some still weakly preserving densely grouped point-like marks. the leaf scars are closely spaced in longitudinal rows, adjacent scars almost touching each other. the vertical ribs separating the leaf scars rows are distinct, about 2 mm wide, strongly depressed and straight, distributed at intervals of 11–12 mm (pl. 3, fig. 1). there is no ornamentation between the leaf scars and the vertical ribs. remarks: the material shows the same leaf scar dimensions, density and distribution, and the lack of ornamentation between the scars as is typically shown by sigillaria tesselata, such as documented by crookall (1966) and josten (1991). this species ranges throughout the westphalian stage (e.g. josten, 1991; cleal, 2007) and there are also records from the stephanian stage (e.g. grand’eury, 1877). genus syringodendron sternberg, 1820 syringodendron sp. (pl. 2, fig. 2) material: a single specimen, no. 0558 in the i.z. barbu collection (university of bucharest). description: an external cast showing widely spaced vertical ribs. remarks: syringodendron is a fossil-genus of decorticated sigillaria-like stems such as this one. it is possible that it was produced by the same species of plant that produced the sigillaria tesselata stems, but it is impossible to be certain. class cycadopsida genus neuralethopteris cremer, 1893 emend. laveine, 1967 neuralethopteris rectinervis (kidston) laveine, 1967 (pl. 3, fig. 2; pl. 4, figs. 1–5) 1888 neuropteris rectinervis – kidston, p. 314–315, pl. 1, figs. 2–4 1967 neuralethopteris rectinervis – laveine, p. 120, pl. 9 material: this species has not been previously recorded from baia nouă but was one of the most abundant in the newly collected material. description: pinnules occur rarely attached to a smooth pinna rachis (pl. 4, fig. 4) but more usually are found detached. the pinnules are linear, elongate (pl. 3, fig. 2), with a cordate or a weakly cordate base, and parallel margins converging quickly to a rounded apex (pl. 4, figs. 1–3). pinnules vary between 5–20 mm in length, usually 15mm, and 5–7 mm in width. the midrib is rather thin, straight for most of its length but may be somewhat decurrent in its most proximal part (pl. 4, figs. 1–3), and occurs along a depression in the lamina. the midrib remains entire for about 90% of the pinnule length, and then divides at least once before reaching the pinnule apex. the secondary veins arise at 45–50° from the midrib, and then usually divide twice before reaching the pinnule margin (pl. 3, fig. 2; pl. 4, figs. 1–5). they bend quickly in the first half of the distance between the midrib and the pinnule margin, reaching the margin at 85–90° on the acroscopic side of the pinnule, usually a little more obliquely (75°) on the basiscopic side (pl. 3, fig. 2; pl. 4, fig. 2); this asymmetry in the venation does not seem to be related to taphonomy. the first division of the secondary veins occurs immediately next to the midrib, and the second just over half way between the midrib and margin. the dichotomies of the secondary veins occur at very narrow angles. the vein density along the pinnule margin varies between 48–60 veins per cm. a rare, small, probably basal pinnule occurs on sample p41/c5/6 (pl. 4, fig. 5) together with more typical dispersed neuralethopteris rectinervis pinnules which litter the hand specimen. it is 5.2 mm long and 2.2 mm wide, with a constricted but not cordate base (pl. 4, fig. 5), a rather wide midrib and denser secondary veins (vein density up to 80 per cm). however, the venation and pinnule geometry is otherwise similar to that of neuralethopteris rectinervis. remarks: the newly collected material shows characters consistent with those of neuralethopteris rectinervis, such as the pinnule shape and size, weakly cordate base, thin mihai e. popa & christopher j. cleal: aspects of romanian palaeozoic palaeobotany and palynology. part iii. the late carboniferous ... geologia croatica 337 plate 3 1 sigillaria tesselata, sample 174, fragment 1, s. cotuţiu collection, national geological museum in bucharest. scale bar: 10mm. 2 neuralethopteris rectinervis, p41/c5/6, fragment 1, m.e. popa collection, university of bucharest. scale bar: 2mm. geologia croatica 65/3geologia croatica 338 midrib, and secondary vein shape, distribution and marginal density. it is the first time that neuralethopteris rectinervis has been recorded from romania, but the specimens compare closely with those that have been documented from northern france (laveine, 1967), northern german (josten, 1991) and the dobrudzha coal basin in bulgaria (tenchov & cleal, 2010). the species is characteristic of the langsettian substage, especially of the lower part. neuralethopteris schlehanii (stur) cremer, 1893 (pl. 5, figs. 1–2) 1877 neuropteris schlehani – stur, p. 289, pl. 28, figs. 7, 8a, b, c 1893 neuralethopteris schlehani – cremer, p. 33 1972a neuropteris schlehani – biţoianu, pl. 2, fig. 12 material: there is a single fragment in the c. eufrosin collection (laboratory of palaeontology, university of bucharest), specimen no. 0504. the original identification of this fragment was neuropteris tenuifolia schlotheim ex sternberg. description: the pinna rachis is smooth, 1mm wide, supporting pinnules inserted at 80–90° to its adaxial surface (pl. 5, fig. 1). the pinnules are elongated, straight-rectangular or slightly falcate, with a weakly cordate base, parallel margins and rounded apex (pl. 5, fig. 2); pinnule length 10– 12 mm, pinnule width 3–4 mm. the pinnules are alternately or suboppositely attached to the rachis through a very short stalk or petiole that is directly continuous with the midrib. the entire frond fragment is preserved three-dimensionally, with rachises and pinnules preserved in different, convergent planes. the pinnule lamina is strongly folded abaxially, with a depressed midrib and margins. the midrib is rather thick, about 70–80% of the pinnule length, and usually straight or in falcate pinnules curved. the secondary veins divide twice, the first time immediately next to the rachis and the second time in the first half of the distance between the midrib and the pinnule margin. the veins reach the margins at 75–85° on the acroscopic side of the pinnule, but at 60° on the basiscopic side. secondary veins do not bend strongly even next to the midrib, where the first dichotomy occurs. the vein density is 40–50 per cm on the pinnule margin. remarks: neuralethopteris schlehanii is characterized by rather short pinnules compared to those of n. rectinervis, with a weakly cordate base and regular, parallel margins, and twice divided secondary veins with a marginal vein density of 36–48 per cm (tenchov & cleal, 2010). goubet et al. (2000) documented material with larger size variations, but with average length of 10 mm and width of 5 mm from north america, where this species records are rare. the romanian fragment shows affinities with neuralethopteris rectinervis, but the secondary vein distribution and density, pinnule base and general pinnule sizes are rather different. tenchov & cleal (2010) described this species from the mogilishte formation in northern bulgaria (dobrudzha coalfield), where it is langsettian in age. the bulgarian material is similar to the romanian material, although the former has slightly more triangular pinnules compared with the more rectangular shape of the latter. biţoianu (1972a, b, 1973) cited neuropteris schlehani and imparipteris (neuropteris) schlehani (table 1) from baia nouă, but the illustration in biţoianu (1972a) is difficult to interpret. 6. discussion most of the taxa that we document here from baia nouă are long ranging and of little value for indicating a stratigraphical age. the notable exceptions are the neuralethopteris species, which elsewhere are regarded as reliable indices of floras of middle namurian to lower westphalian (langsettian) age (laveine, 1967; josten, 1983, 1991; cleal & thomas, 1994; cleal, 2005, 2007; tenchov & cleal, 2010). in the appalachians it is restricted to the pocahontas and lower new river formations, which are thought to correlate with the lower langsettian substage in the european chronostratigraphical scheme (goubet et al., 2000; blake et al., 2002). in the donets basin (ukraine) neuralethopteris is restricted to the bashkirian stage (novik, 1952; fissunenko & laveine, 1984), which is probably equivalent to the namurian and early westphalian stages. most previous studies have in contrast ascribed a late westphalian or possibly early stephanian stratigraphical age to the baia nouă flora. on the basis of the published species lists such an interpretation might be viable, but it is difficult to make a critical judgement as the published illustrations of the fossils are generally poor and there are few voucher specimens to verify the identifications. one of the key taxa listed in these earlier studies is neuropteris ovata hoffmann, which would be a strong indicator of asturian or stephanian age, but the specimens figured by biţoianu (1972a, pl. 2, fig. 15; 1972b, pl. 2, fig. 16) have linguaeform pinnules and a strong midvein, and look remarkably like the specimens described here as neuralethopteris rectinervis. the presence of alethopteris serlii (brongniart) goeppert would also suggest a late asturian or cantabrian age (e.g, see discussion in zodrow & cleal, 1998) but the specimen figured by biţoianu (1973, pl. 2, fig. 13) does not show the venation clearly (a feature critical for the correct identification of this species) and pinnules of similar shape also occur in alethopteris lancifolia wagner, which is wellknown from early westphalian floras (e.g. wagner, 1961, 2005). the specimen figured by biţoianu (1972a, pl. 3, fig. 19) as mariopteris nervosa (brongniart) zeiller, another indicator of a late westphalian age, is similarly undiagnostic for this species. none of the illustrated specimens from baia nouă is in fact incompatible with a langsettian age indicated by the evidence presented in this paper. this makes the sirinia basin rather different from most of the other intramontane basins in europe, which tend to be late westphalian and stephanian in age (e.g. doubinger & vetter, 1983; cleal et al., 2010, 2011). a well-documented intramontane basin in europe that includes early westphalian deposits and macrofloras is the svoge basin in bulgaria (tenchov, 1976, 1977, 2007). in eastern serbia, within the stara planina – poreč terrane (corresponding to the mihai e. popa & christopher j. cleal: aspects of romanian palaeozoic palaeobotany and palynology. part iii. the late carboniferous ... geologia croatica 339 plate 4 1 neuralethopteris rectinervis, sample p41/c5/23, m.e. popa collection, university of bucharest. scale bar: 2mm. 2 neuralethopteris rectinervis, sample p41/c5/17, m.e. popa collection, university of bucharest. scale bar: 2mm. 3 neuralethopteris rectinervis, sample p41/c5/11, m.e. popa collection, university of bucharest. scale bar: 2mm. 4 neuralethopteris rectinervis, sample p41/c5/31, m.e. popa collection, university of bucharest. scale bar: 2mm. 5 neuralethopteris rectinervis, sample p41/c5/6, m.e. popa collection, university of bucharest. scale bar: 2mm. geologia croatica 65/3geologia croatica 340 plate 5 1 neuralethopteris schlehanii, sample 0504, c. eufrosin collection, university of bucharest. scale bar: 10mm. 2 neuralethopteris schlehanii, detail of sample 0504, c. eufrosin collection, university of bucharest. scale bar: 1mm. mihai e. popa & christopher j. cleal: aspects of romanian palaeozoic palaeobotany and palynology. part iii. the late carboniferous ... geologia croatica 341 upper danubian units), occur terrestrial sediments (krstić & maslarević, 1997), with a floral assemblage dominated by lycopsids marking the langsettian (late bashkirian) – westphalian (moscovian) interval (pantić, 1955, 1963, krstić et al., 2005, djordjević-milutinović, 2010). western serbia includes a drifted, allochtonous bashkirian – early moscovian flora (krstić et al., 2005) within the stojković formation, belonging to the jadar block terrane, with a different tectonic setting to that of the balkan terrane. the svoge, stara planina-poreč and sirinia basins were positioned on the balkan terrane (yanev, 2000; yanev et al., 2005), a gondwana-derived microplate that docked with laurussia in late carboniferous times and which ultimately became part of the variscan mountains. whether this means there is a genetic link between the svoge, eastern serbia and sirinia basins, however, must remain unclear until more is learnt about these romanian deposits. 7. conclusions the study of the floral assemblage of the cucuiova formation in baia nouă is based mainly on freshly collected material as well as on previous, historical collections. the results show a series of key species (neuralethopteris recti ner vis, n. schlehanii) marking the middle namurian – late westphalian (langsettian, late bashkirian) time interval, associated with species which have wider ranges, but which are not incompatible to the langsettian age proposed for the lower part of the cucuiova formation in baia nouă. therefore, baia nouă hosts the oldest pennsylvanian (langsettian) sediments in the sirinia basin, older than in any other pennsylvanian locality in the sirinia basin (cucuiova area, povalina valley, cameniţa area, dragosela valley), in the danubian units and even in the south carpathians. this age makes the cucuiova formation in baia nouă comparable to early westphalian sediments of the svoge and eastern serbian (stara planina – poreč) basins. acknowledgement the authors wish to thank dr ştefan grigorescu, head of the geological institute of romania, and dr valentin paraschiv, palaeobotany curator of the national geological museum (geological institute of romania) in bucharest, for permitting the access to the palaeobotany collections, especially to the s. cotuţiu collection, as part of a bilateral agreement for cooperation. mrs raluca m. popa is thanked for help in the field during the summer 2011 collecting trip. the scientific council and the administration of the iron gates natural park are thanked for understanding and for approval of paleontological activities undertaken in the area. we thank professor stanislav opluštil (prague), professor jasenka sremac (zagreb) and dr milan libertin (prague) for improving the manuscript through their constructive observations and advice. this paper is a contribution to igcp 575 project pennsylvanian terrestrial habitats and biotas of southeastern euramerica, as well as to pnii-pc paleoclim project no. 31-063/14.09.2007. references berza, t., krautner, h. & dimitrescu, r. (1983): nappe structure of the danubian window of the central south carpathians.– anuarul institutului de geologie şi geofizică, 60, 31–34. biţoianu, c. (1972a): observaţii asupra conţinutului paleobotanic al depozitelor carbonifere din zona baia nouă (banat).– studii şi cercetări de geologie, geofizică, geografie, secţia geologie, 17, 125–130. biţoianu, c. (1972b): conţinutul floristic al depozitelor carbonifere din zona sviniţa.– studii şi cercetări de geologie, geofizică, geografie, secţia geologie, 17, 391–399. biţoianu, c. (1973): la flore du carbonifere superieur de la roumanie.– compte rendu 7e congrès international de stratigraphie et de géologie du carbonifère (krefeld, 1971), 2, 115–127. biţoianu, c. (1974): le silezien des carpathes meridionales (roumanie).– bulletin de la société belge de géologie, de paléontologie et d‘hydrologie, 83, 131–133. biţoianu, c. (1987): consideraţii paleobotanice, petrografice şi genetice asupra huilelor carbonifere din banat.– contribuţii botanice, 27, 89–97. biţoianu, c. & ilie, s. (1968): asupra prezenţei sclerotinitului în huila carboniferă de pe valea dragosella (banat).– studii şi cercetări de geologie, geofizică, geografie, secţia geologie, 13, 243–247. blake, b. m., cross, a. t., eble, c. f., gillespie, w. h., & pfefferkorn, h. w. (2002): selected plant megafossils from the carboniferous of the appalachian region, eastern united states: geographic and stratigraphic distribution.– canadian society of petroleum geologists memoir, 19, 259–335. brongniart, a. (1822): sur la classification et la distribution des végétaux fossiles en général, et sur ceux des terrains de sediment supérieur en particulier.– mémoires du museum d’histoire naturelle, paris, 8, 203–240, 297–348. brongniart, a. (1837): histoire des végétaux fossiles 1(11–12).– g. dufour & e. d’ocagne, paris. cleal, c.j. (2005): the westphalian macrofloral record from the cratonic central pennines basin, uk.– zeitschrift der deutschen gesellschaft für geowissenschaften, 156, 387–410. cleal, c.j. (2007): the westphalian-stephanian macrofloral record from the south wales coalfield.– geological magazine, 144, 465–486. cleal, c.j., opluštil, s., thomas, b.a. & tenchov, y. (2010): late moscovian terrestrial biotas and palaeoenvironments of variscan euramerica.– netherlands journal of geosciences, 88, 181–278. cleal, c.j., opluštil, s., thomas, b.a. & tenchov, y. (2011): pennsylvanian vegetation and climate in tropical variscan euramerica.– episodes, 34, 3–12. cleal, c.j. & thomas, b.a. (1994): plant fossils of the british coal measures.– palaeontological association, london. cleal, c.j. & thomas, b.a. (2005): palaeozoic tropical rainforests and their effect on global climates: is the past the key to the present?– geobiology, 3, 13–31. codarcea, a. (1940): vues nouvelles sur la tectonique du banat meridional et du plateau de mehedinţi.– dări de seamă ale şedinţelor comitetului geologic, 20, 1–74. cremer, l. (1893): über die fossilen farne des westfälischen carbons und ihre bedeutung für eine gliederung des letzeren.– universität marburg. crookall, r. (1966): fossil plants of the carboniferous rocks of great britain [second section]. part 4.– memoirs of the geological survey of great britain, palaeontology, 4, 355–572. geologia croatica 65/3geologia croatica 342 crookall, r. (1969): fossil plants of the carboniferous rocks of great britain [second section]. part 5.– memoirs of the geological survey of great britain, palaeontology, 4, 573–792. djordjević-milutinović, d., 2010. overview of the paleozoic and mesozoic sites with macroflora in serbia. bulletin of the natural history museum 3, 27–46. doubinger, j. & vetter, p. (1985): la flore de l’assise de rivede-gier (bassin de saint étienne, france).– compte rendu 10e congrès international de stratigraphie et de géologie du carbonifère (madrid, 1983), 3, 161–167. dragastan, o., popa, m.e., ciupercianu, m. (1997): the late palaeozoic phytostratigraphy and palaeoecology of the southern carpathians (romania).– in: primul simpozion naţional de paleontologie, bucureşti. acta palaeontologia romaniae, 1, 57–64. fissunenko, o.p. & laveine, j.p. (1984): comparaison entre la distribution des principales espèces-guides végétales du carbonifère moyen dans le bassin du donetz (urss) et les bassins du nord-pas-de-calais et de lorraine (france).– compte rendu 9e congrès de stratigraphie et de géologie du carbonifère (washington and urbana, 1979), 1, 95–100. goubet, p., pfefferkorn, h.w. & gillespie, w.h. (2000): neuralethopterids (trigonocarpalean pteridosperms) from the early pennsylvanian of eastern north america.– paleobios, 20, 11–37. grand’eury, m. (1877): flore carbonifère du departement de loire et du centre de la france.– mémoires présentés par divers savants à l’académie des sciences, 24, 1–624. hantken, m.p. (1878): die kohlenflötze und der kohlenbergbau in den ländern der ungarischen krone.– legrady testeverek, budapest. ilie, s. & biţoianu, c. (1966): asupra prezenţei speciei cellulasclerotes giganteus în depozitele carbonifere de pe valea dragosella (banat).– studii şi cercetări de geologie, geofizică, geografie, secţia geologie, 11, 251–252. josten, k.h. (1983): die fossilen floren im namur des ruhrkarbons.– fortschritte in der geologie von rheinland und westfalen, 31, 1–327. josten, k.h. (1991): die steinkohlen-floren nordwestdeutschlands.– fortschritte in der geologie von rheinland und westfalen, 36, 1–434. krstić, b. & maslarević, l., (1997): the palaeozoic of djerdap. geology of djerdap area.– in: grubic a. & berza, t. (eds.): geology in the danube gorges (yugoslavia and romania). geoinstitute of belgrade, belgrade, 25–28. krstić, b., filipović, i., maslarević, l., sudar, m., & ercegovac, m. (2005.): carboniferous of the central part of the balkan peninsula. academie serbe des sciences et des arts, sciences naturelles, 43, 42–56. laveine, j.-p. (1967): contribution a l’étude de la flore du terrain houiller. les neuroptéridées du nord de la france.– études géologiques pour l’atlas topographie souterraine, 1(5), 1–344. mateescu, i. (1964): studiu asupra metamorfismului cărbunilor de la baia nouă, bazat pe considerente petrografice şi chimice.– studii tehnice şi economice, 1, 5–57. maxim, i.a. (1967): noi contribuţiuni asupra florei fosile de la sviniţabanat, cu o privire comparativă între flora permo-carboniferă din zona sviniţa, reşiţa şi sudul dunării.– studia universitatis babeşbolyai, geologie, 2, 9–17. maxim, i.a. (1969): cîteva plante din stephanianul superior de la sviniţa (banat).– studii şi cercetări de geologie, geofizică, geografie, secţia geologie, 14, 405–422. năstăseanu, s. (1984): geology of the main coal basins in romania.– anuarul institutului de geologie şi geofizică, 64, 195–204. năstăseanu, s. (1987): upper paleozoic molasse deposits in the romanian south carpathians.– in: flugel, e., sassi, f. & grecula, p. (eds): pre-variscan and variscan events in the alpine-mediterranean mountain belts. alfa bratislava, bratislava, 371–378. năstăseanu, s., bercia, i., iancu, v., vlad, s. & hârtopanu, i. (1981): the structure of the south carpathians (mehedinţi – banat area).– igr, bucharerst. năstăseanu, s., stănoiu, i. & biţoianu, c. (1973): corelarea formaţiunilor molasei hercinice (westfalian-permian) din partea vestică a carpaţilor meridionali.– anuarul institutului de geologie şi geofizică, 40, 71–109. novik, e.o. (1952): kamennougol’naya flora evropeiskoi chasti sssr.– paleontologiya sssr, novaya seriya, 1, 1–468. opluštil, s. & cleal, c.j. (2007): a comparative analysis of some late carboniferous basins of variscan europe.– geological magazine, 144, 417–448. pantić, n., (1955.): contribution a la connaissance de la paleoflore de serbie (i). recueil des travaux de l institut de geologie “jovan zujovic” 8, 203–220. pantić, n. (1963.): phytostratigraphy of devonian and carboniferous deposits of the carpato-balkanides (estern serbia), fifth congress of the carpathian-balkan geological association, bucharest, 107–115. popa, m.e. (2005): aspects of romanian palaeozoic palaeobotany and palynology. part ii. overview of the upper carboniferous formations in the south carpathians.– zeitschrift der deutschen gesellschaft für geowissenschaften, 156, 415–430. popa, m.e. (2011): field and laboratory techniques in plant compressions: an integrated approach.– acta palaeontologica romaniae, 7, 279–283. răileanu, g. (1953): cercetări geologice în regiunea sviniţa – faţa mare.– buletin ştiinţific al academia republicii populare romîne, secţiunea de stiinte biologice, agronomice, geologice si geografice, 5, 307–409. răileanu, g. (1960): recherches geologiques dans la region sviniţa – faţa mare.– anuar comitetului de stat al geologiei românia, 26/28, 347–383. răileanu, g., grigoraş, n., onescu, n. & plişcă, t. (1963): geologia zăcămintelor de cărbuni, cu privire specială asupra teritoriului rpr.– bucharest. schafarzik, f. (1894): die geologischen verhältnisse der umgebungen von eibenthal–ujbánya, tiszovicza und svinyicza.– jahresberichte der königlichen ungarischen geologischen anstalt, 1892, 140–159. seghedi,a., popa, m.e., oaie, g. & nicolae, i. (2001): the permian system in romania.– in: cassinis, g. (ed.): permian continental deposits of europe and other areas. regional reports and correlations, brescia, 281–293. seghedi, i. (2010): permian rhyolitic volcanism, changing from subaqueous to subaerial in post-variscan intra-continental sirinia basin (se romania–eastern europe).– journal of volcanology and geothermal research, 201, 312–324. semaka, a. (1962): observaţii asupra florelor paleomesozoice din danubianul banatului.– dări de seamă ale şedinţelor comitetului geologic, 47, 309–321. semaka, a. (1970): geologisch-paleobotanische untersuchungen in s.o. banaten danubikum.– memoriile comitetului geologic, românia, 11, 1–79. shute, c.h. & cleal, c.j. (1986): palaeobotany in museums.– geological curator, 4, 553–559. stănoiu, i. & stan, n. (1986): litostratigrafia molasei permian-carbonifere din regiunea munteana-sviniţa-tîlva frasinului (banatul de sud). – dări de seamă ale şedinţelor comitetului geologic, 70/71, 39–50. mihai e. popa & christopher j. cleal: aspects of romanian palaeozoic palaeobotany and palynology. part iii. the late carboniferous ... geologia croatica 343 sternberg, k.m. von (1820–1821): versuch einer geognostischbotanischen darstellung der flora der vorwelt 1(1) [1820], 1(2) [1821].– fleischer, leipzig. sternberg, k.m. von (1823): versuch einer geognostisch-botanischen darstellung der flora der vorwelt 1(3).– e. brenck‘s wittwe, regensburg. stur, d. (1870): beitrage zur kenntnis der dyas und steinkohlen-formation im banate.– jahrbuch der kaiserlich-königlichen geologischen reichsanstalt, 20, 185–200. stur, d. (1877): die culm-flora der ostrauer und waldenburger schichten.– abhandlungen der kaiserlich-königlichen geologischen reichsanstalt, 8/2, 107–472. tenchov, y.g. (1976): composition peculiarities of the carboniferous flora of the svoge basin, west bulgaria.– geologica balcanica, 6, 3–11. tenchov, y.g. (1977): flora und biostratigraphie des oberkarbons im svoge-becken (vr bulgarien).– schriftenreihe für geologische wissenschaften, 7, 1–163. tenchov, y.g. (2007): the carboniferous of svoge coalfield (bulgaria).– geologica balcanica, 36, 5–15. tenchov, y.g. & cleal, c.j. (2010): neuralethopteris foliage (medullosales) in the carboniferous of dobrudzha coalfield, bulgaria.– review of palaeobotany and palynology, 158, 298–307. tietze, e. (1872): geologische und palaeontologischen mitteilungen aus dem südlichen theil der banater gebirgstockes.– jahrbuch der kaiserlich-königlichen geologischen reichsanstalt, 22. wagner, r.h. (1961): somealethopterideae from the south limburg coalfield.– memoirs of the geological foundation of the netherlands, new sites, 14, 5–13. wagner, r.h. (2005): alethopteris lancifolia wagner, a rare element of the lower westphalian fern ledges of atlantic canada.– revista española de paleontología, 20, 15–19. yanev, s. (2000): palaeozoic terranes of the balkan peninsula in the framework of pangea assembly.– palaeogeography, palaeoclimatology, palaeoecology, 161, 151–177. yanev, s., lakova, i., boncheva, i. & schanski, v. (2005): the moesian and balkan terranes in bulgaria: palaeozoic basin development, palaeogeography and tectonic evolution.– geologica belgica, 8/4, 185–192. zeiller, r. (1879): explication de la carte géologique de la france, seconde partie, végétaux fossils du terrain houiller de la france. j.b. bailliére & fils, paris (atlas published in 1878). zodrow, e.l. & cleal, c.j. (1998):. revision of the pteridosperm foliage alethopteris and lonchopteridium (upper carboniferous), sydney coalfield, nova scotia, canada.– palaeontographica, abteilung b, 247, 65–122. manuscript received may 03, 2012 revised manuscript accepted october 08, 2012 available online october 30, 2012 04_kovacevic.indd 53 kovačević galović et al.: geochemical discrimination of early palaeogene bauxites in croatia �ab stra ct two discriminant function models were created in order to distinguish between majorand trace-element geochemical patterns typical of lower palaeogene (palaeocene, pc) bauxites formed on the portion of the carbonate platform comprising the karst or external dinarides. four groups of bauxites from istria, north adriatic islands, north dalmatia and central dalmatia have been distinguished, according to their specifi c combinations of major and trace elements, characteristic conditions of formation, and processes prevailing in the karst environment during subaerial exposure of the carbonate platform. typically, in both models the fi rst discriminant function explains most of the system variability. however, the trace-element model proves itself as a more helpful predictive tool, representing the straightforward example of classifi cation of the samples into four pre-defi ned groups of pc bauxites. generally, both models follow a characteristic trend in geochemical signature related to the recent geographical position of the bauxite deposits, namely a decrease in k2o and an increase in the cr content in a se direction (from istria to dalmatia). this was most probably the result of environmental conditions during the adcp cretaceous-palaeogene emergent stage (istria), and emplacement of parent rocks (ophiolite belt) supplying the necessary material for bauxite genesis (central dalmatia). keywords: bauxite; adriatic carbonate platform; dinarides; geochemistry; discriminant function model geochemical discrimination of early palaeogene bauxites in croatia � erli kovačević galović, nikolina ilijanić, zoran peh, slobodan miko and ozren hasan croatian geological survey, sachsova 2, p.o. box 268, hr-10000 zagreb, croatia; (corresponding author: ekovacevic@hgi-cgs.hr) doi: 104154/gc.2012.04 geologia croatica 65/1 53–65 6 figs. 6 tabs. zagreb 2012 geologia croaticageologia croatica 1. introduction unlike many other types of ores and raw materials, bauxites were for a long time treated only as an aluminum ore, with all research efforts focused on the assessment of conditions of their detection, exploitation and refi nement. in spite of a great number of mineralogical and chemical analyses (albeit only partial in most cases), from bauxite deposits and occurrences in croatia being available in various studies and professional reports, bauxite genesis, particularly in relation to the adjacent karst (palaeo)environment and its tectonostratigraphic constraints, was largely underestimated. only lately, have models of the orogenic evolution of the adriatic (adriatic–dinaric) carbonate platform (adcp) with special reference to external dinarides of the ne adriatic region underlined the importance of a number of hiatuses of variable duration marked by bauxitic deposits (vlahović et al., 2005; korbar, 2009). since bauxites are now well recognized as tectonic and climatic event markers at regional unconformities, these investigations call for additional correlative studies within and across different stratigraphic hori zons, bearing in mind that clearly expressed emergent surfaces set the stage for the resonant interplay of tectonics, volcanism, eustasy and climate on various parts of the carbonate platform (d’argenio & mindszenty, 1995). such a complex bauxite research seems indispensable in the light of the new lithostratigraphic scheme that became the basis for regional correlation studies within the entire region of the croatian karst dinarides during the last two decades (e.g. matičec et al., 1996; tišljar et al., 2002; vla hović et al., 2002; dragičević & velić, 2002). the amassed data in the plentiful literature on croatian bauxites (e.g. šinkovec, 1973; sakač et al., 1987; šinko vec & sakač, 1981; šušnjara et al., 1990; sakač et al., 1984; šinkovec et al., 1994) is largely confi ned within the limits of particular deposits, stratigraphic horizons, or local unconformities, geologia croatica 54 geologia croatica 65/1 but has immense potential indispensable in building regional models of platform evolution, except for rarer works addressing a wider scope (e.g. sakač & šinkovec, 1991). croatian bauxites are hosted in carbonate rocks marking regional unconformities between several stratigraphic levels, of which the upper cretaceous – lower palaeogene hiatus can be singled out as a major one. in some parts of the adcp (istrian karst) emergence was uncharacteristically long, from as far back as the lower cretaceous (matičec et al., 1996; croatian geological survey, 2009), while elsewhere it was much shorter. the extent of subaerial exposure during the stratigraphic gaps is of particular importance in understanding the origin of bauxites, which is why the geochemical and mineralogical signature has much to say about the intervening processes prevailing on the emergent carbonate platform. the lower palaeogene (palaeocene, pc) bauxites are specifi cally targeted for this purpose owing to their variable time span of emplacement (lower cretaceous to lower eocene) within the adcp (from ne to se), and assumed differences in geochemical signal received during exposure. accordingly, the main purpose of this investigation was to assess the geochemical contrast (aided by qualitative mineralogical analysis) among the different groups of pc bauxites previously defi ned in relation to their palaeographical/palaeotectonic settings (fig. 1) to this effect, a multivariate statistical assessment of a primary geochemical pattern distinguishing between samples from istria, the north adriatic islands, north dalmatia (drniš area) and central dalmatia (imotski area) was performed, preferring multiple discriminant analysis (mda) as the most helpful mathematical tool. the latter is employed as a method of data reduction and organization which offers a quick, simple and effective means of clarifying signifi cant groupings and trends among environmentally distinct sediment samples, in this case solely on the basis of their geochemical composition. 2. materials and methods 2.1. geological setting the area of the croatian karst (external or outer) dinarides is a thick carbonate succession deposited from the middle permian (or even upper carboniferous) to the eocene on platforms of different ages, type and palaeogeographical setting. the evolution of the karst dinarides area started on an epeiric carbonate platform along the northern gondwana margin with a signifi cant deposition of mixed carbonate-siliciclastic sediments in the permian, and mostly siliciclastic deposits in the early triassic (vlahović et al., 2002). in the middle triassic, steep faults formed in the basement and separation of the adria microplate occurred, characterized by carbonate facies with locally signifi cant volcaniclastic infl uence. a late triassic succession of hauptdolomite and dachstein limestones represents typical deposits of the huge isolated southern tethyan megaplatform (vlahović et figure 1: shaded relief map of croatia with superimposed area showing the recent distribution of adriatic (adriatic-dinaric) carbonate platform (compiled from vlahović et al., 2005) and locations of sampled early palaeogene bauxites. border between the adriatic and dinaric units inferred (partly) after korbar, 2009. geologia croatica 55 kovačević galović et al.: geochemical discrimination of early palaeogene bauxites in croatia al., 2005). during the late liassic, it was dissected into smaller carbonate platforms, resulting in formation of the adriatic basin, with the adriatic carbonate platform (adcp) along its eastern side. this was marked by predominantly shallow-marine deposition, but a combination of synsedimentary tectonics and eustatic changes resulted in frequent emersions of variable duration, characterized by local deposition of bauxites. according to other authors (korbar, 2009, and references therein), two carbonate platforms (adriatic and dinaric), separated by the inter-platform budva-cukali basin, were formed instead of the single adcp. these were used as a basis for a new model of the mesozoic–cenozoic evolution of the region and further divided into four tectonostratigraphic units: dinaridic ne unit (inner karst), dinaridic sw unit (high karst), adriatic ne unit (dalmatian karst) and adriatic sw unit (istrian karst). disintegration of the platform(s) and the appearance of fl ysch basins began in the late cretaceous, while the transition from the cretaceous to the palaeogene was marked everywhere on the adcp by a period of emersion. intense tectonics continued through the palaeogene, with carbonate deposition on carbonate ramps, while tectonic contraction of the platform area during the oligocene-miocene resulted in the uplift of the dinarides. one of the most distinctive features of the dinarides is the widespread occurrence of ophiolites generated in subduction processes, fi rst in dinaridic tethys and later in the back-arc basin (pamić et al., 2002). the obducted ophiolites are predominantly peridotite tectonites, enriched in ree typical for ultramafi c rocks. occurrences and deposits of bauxites can be found at several stratigraphic levels over the entire region of the croatian karst dinarides – from istria to dalmatia (šinkovec & sakač, 1981; sakač et al., 1978; šebečić et al., 1985; sakač et al., 1984). some (predominantly of upper eocene age from the outer dinarides), had large reserves of signifi cant, economy-grade bauxite ore, but these are for the most part totally exhausted. considering the whole formative period of the adcp, the palaeogene was particularly distinctive by a substantial shift of bauxite formation toward the more external zones of the external (outer) dinarides (šinkovec & sakač, 1991). as a result, the majority of deposits formed between the palaeocene and upper eocene, before the fi nal disintegration of the platform that culminated during the oligocene-miocene (vlahović et al., 2005). before that, at the onset of the tertiary period, pc bauxites formed extensively over the low-lying, emerged sw part of the adcp including istria (adriatic sw unit), adriatic islands, and most of dalmatian hinterland (dinaridic sw unit) (korbar, 2009) occurring almost invariably in the form of small-size, economically often insignifi cant, ore bodies. 2.2. field and analytical procedures 2.2.1. sampling a total of 50 bauxite samples of palaeocene age were collected from various sites (deposits and occurrences) in istria (21), on the north adriatic islands (12) including krk, cres, rab, goli and pag, in northern dalmatia (8) and in central dalmatia (9). at all locations samples represent the bulk geochemical signature of bauxites infi lling a single regional unconformity (cretaceous-palaeogene transition), irrespective of particular horizons within the ore body (e.g. at the contact with the related palaeokarst), possibly with a different geochemical signal related to issues of bauxite autochthony-allochthony or vadosephreatic depositional-diagenetic environments (d’argenio & mindszenty, 1995; bardossy, 1982). it is presupposed here that multivariate analysis performed on the bulk geochemistry of a number of samples, can pinpoint the most important geochemical processes, by averaging all details down the vertical profi le. detailed investigation at a single site ought to be performed later in order to screen geochemical and mineralogical data with particular reference to processes controlling the geochemical facies of bauxites in a specifi c part of the lithologic column. it must also be noted in passing, that all investigated bauxites are treated as being of lower paleogene (pc) age, according to the age of the cover rocks, in spite of a possibility that some istrian bauxites may have formed during more than one emergent stage due to a prolonged hiatus marked by non-deposition (šinkovec, 1973). 2.2.2. sample preparation and analysis fresh bauxite samples weighing about 3 kg in total were chipped and crushed by hand and fi nally split into fractions by quartering. whole-rock samples were subsequently ground in a tungsten carbide pestle mortar mill (retsch lab equipment) to pass through a <0.063 mm sieve to be prepared for the analytical work. chemical analysis was performed at the acme analytical laboratories in vancouver, canada, using the lithogeochemical whole rock major and trace element analytical method. total abundances of the major oxides and several minor elements are reported on a 0.2g sample analysed by icp-emission spectrometry following a lithium metaborate/tetraborate fusion and dilute nitric acid digestion. total trace elements were analyzed by icp-ms. refractory elements underwent the same decomposition as the major elements (additional 0.2 g sample) while the rest are digested in hot aqua regia and analyzed by icp mass spectrometry (0.5 g sample). bauxite samples were analysed for a total of 32 elements including 10 major element (oxides): sio2, al2o3 fe2o3, mgo, cao, na2o, k2o, tio2, p2o5 and mno; and 22 trace elements: as, ba, cd, ce, co, cr, cu, ga, hg, la, mo, nb, ni, pb, sc, sr, th, u, v, y, zn and zr. mineralogical analysis was performed by x-ray diffraction (xrd analysis) where the mineral composition of all samples was determined by the panalytical x’pert powder diffractometer. the device is equipped with ni-fi lter cukα radiation, vertical goniometer with θ/θ geometry and pixcel detector. scan conditions were: 45kv and 40 ma, ¼ divergence slit and ½ antiscatter slits, step size 0.02° 2θ, time per step 2s. the sieved samples were then back-loaded on aluminum holders, to ensure random mineral orientation. powder diffraction data were collected in the range of 5-66° 2θ. mineralogical analysis was performed on four samples prepared in the same manner as for geochemical analysis. only one sample representative of each single group was selected for the purpose. selection was based on the mean value of geologia croatica 56 geologia croatica 65/1 the major-element compositions so that the least value of the squared mahalanobis distance (smd) for each group (the least distance from the group centroid), was used as a criterion. mineralogical analysis was obtained by xrd on the bulk samples (ipc-7, krk-4, dr-11, and impc-1). the following mineral compositions were determined: boehmite, haematite, goethite and anatase in samples dr11, impc1 and krk4. sample ipc7 is different because it contains gibbsite which doesn’t appear in other samples. boehmite is a dominant mineral phase in the 3 samples, while haematite, goethite and anatase appear in minor amounts. boehmite was determined by the diffractions maximums on d=6.10, 3.16, 2.34 and 1.86 å. haematite has its characteristic peaks on d=3.68, 2.69, 2.51 and 1.69 å. goethite has diffraction maximums on d=4.16, 2.69 and 2.45 å. anatase was identifi ed by peaks d=3.51, 2.37 and 1.66 å. gibbsite appears only in sample ipc7 and was determined by strong refl ection peaks on d=4.84, 4.37 and 3.31 å. 3. statistical considerations 3.1. the data a set of 32 elements including 10 major and 22 trace elements was selected as predictor variables in building the original discriminant model. summary statistics for the whole dataset prior to the multivariate statistical procedure are displayed in table 1 (minimum, maximum, median, mean, standard deviation and skewness). since most of the variables are characterized by non-normal, positively skewed, frequency distributions (except al2o3 and tio2, ga, nb, th and zr which are negatively skewed), appropriate transformations were found necessary to acquire a more symmetric distribution. as a general rule, most geochemical data do not follow normal (neither lognormal) distribution (e.g. matschullat et al. 2000; reimann & filzmoser, 2000; reimann et al. 2005); a problem arising from complex non-linear dynamics, feedbacks and thresholds within a natural system characterized by the particular suite of variables (e.g. hugget 1998; phillips, 1999). univariate distributions of the input data were examined by the shapiro-wilks w test of normality (added to table 1 as p-values before and after normalization). conventional normalization procedure using log-transformations was subsequently applied where necessary to stabilize the variance of the original data. this process included all the major elements except p2o5, and a greater part of the trace elements exclusive of ga, la, nb, sc, th and zr which are normally distributed (all marked by the asterisk). according to the applied test, 17 more variables attained normal distribution after normalization (sio2, fe2o3, mgo, cao, as, ba, cd, ce, co, cu, hg, mo, pb, sr, v, y and zn (p>0.05, marked by double asterisk)). however, where the normalization procedure failed, having produced an even greater skew with respect to the original distribution (such as with al2o3 and na2o), the data were rather left untransformed. as with all multivariate statistical procedures, yet another assumption had to be made before dfa can be successfully utilized in research – that of suffi cient sample size supplying enough information upon which to found analysis. based on the variety of general recommendations considering the importance of sample size and sample-to-size ratio reviewed in a number of works (e.g. arrindel & van der ende, 1985) 50 observations was deemed suffi cient but major and trace elements were analyzed as separate data matrices. 3.2. building a discriminant function model (dfm) multiple (multi-group) discrimination analysis (mda) is a statistical technique that is particularly useful when applied to distinguish between several pre-defi ned groups based on a great number of observations. its purpose, defi ned in a statistical sense, is to maximize the between-group variance in comparison to the variance within each group (e.g. dillon & goldstein, 1984). in the process, a hypothesis is tested that all observed groups have the same multivariate mean against the alternative that at least one multivariate mean is different (rock, 1988). provided that alternative hypothesis is accepted (which does not mean that each pair of groups must necessarily be plainly separated and distinct), the original set of data is then recalculated by mda into a number of discriminant scores, allocating each object or group (the latter represented by its mean), along one or more lines – linear discriminant functions (e.g. krumbein & greybill, 1965; doornkamp & king, 1971; davis, 1986). in this way the multivariate problem simply collapses into a fewer-dimension solution, one less than the number of groups (k-1), or equal to the number of variables (p), whichever is the smaller. here, discriminant analysis from the statistical software package of statistica, release 7.1 (statsoft, inc., 2006) was used to investigate chemical differences between the four groups of bauxites separated previously by independent criteria such as their geographical position and palaeotectonic settings within the adcp as a major geotectonic unit. the groups containing 50 samples were determined as early palaeogene (palaeocene) bauxites and sampled from different quarters of the adcp, namely istria (ist), north-adriatic islands (nai), north dalmatia (nda), and central dalmatia (cda), roughly following the position of the formerly established tectonostratigraphic units (korbar, 2009). in order to achieve the best separation between groups and explain the geological causes underlying the structure of input data, two discriminant models were constructed based on the two sets of predictor variables, namely the bulk concentrations of major (10) and trace elements (22). 4. results and discussion the results of the mda are briefl y summarized in the joint table (tab. 2) comprising both research models containing major and trace elements. the overall signifi cance of their discrimination is tested by the appropriate multivariate tests (tab. 3) showing the extremely low associated probabilities (p<0.000) in both cases, which is required to safely proceed with computing discriminant functions (dfs). since the same number of groups (k=4) is studied in both models, the between-group variation is completely explained by the three dfs (k-1). table 2 reveals that in both models, df1 explains geologia croatica 57 kovačević galović et al.: geochemical discrimination of early palaeogene bauxites in croatia the largest portion of the total variability hidden within the original mainand trace elements data spread, amounting to almost 80% for the latter. note, however, that in the traceelement dfm the third function (df3) exhibits a low contribution to the total variance, which can be seen both by the tested signifi cance (p=0.146) and low eigenvalues (tab. 2), meaning that only the fi rst two dfs are suffi cient to separate the four bauxite groups based on their trace element content. 4.1. functional models (labeling discriminant space) labelling dfs is an essential part of the analysis since it offers a geologically meaningful interpretation to the whole discrimination scheme. through this process the hidden mathematical table 1: descriptive statistics. element min mean med max stdev skew s–w(p) s–w(p1) sio2 (%) 1.02 3.914 3.415 9.10 2.059 0.825 0.004 **0.560 al2o3 (%) 34.50 50.114 50.415 58.58 5.308 -0.890 0.021 – fe2o3 (%) 14.76 26.114 25.955 45.96 5.294 0.993 0.027 **0.750 mgo (%) 0.06 0.137 0.11 0.49 0.077 2.388 0 **0.070 cao (%) 0.04 0.126 0.115 0.64 0.094 3.525 0 **0.116 na2o (%) 0.005 0.02 0.01 0.33 0.046 6.664 0 – k2o (%) 0.005 0.046 0.03 0.20 0.047 1.761 0 0.012 tio2 (%) 1.60 2.889 2.955 3.88 0.493 –0.699 0.030 0.030 p2o5 (%) 0.005 0.054 0.053 0.113 0.025 0.046 *0.608 – mno (%) 0.02 0.079 0.05 0.46 0.083 3.256 0 0.013 as (mg/kg) 1.7 39.198 36.15 154.9 32.304 1.844 0 **0.132 ba (mg/kg) 6.0 26.280 24.0 73.0 13.028 1.749 0 **0.117 cd (mg/kg) 0.1 2.03 1.2 11.0 2.438 2.250 0 **0.567 ce (mg/kg) 64.6 233.218 193.8 645.3 130.050 1.321 0 **0.825 co (mg/kg) 14.2 41.33 38.2 91.9 16.866 1.070 0.004 **0.985 cr (mg/kg) 362.76 713.07 578.37 1423.62 309.056 0.835 0 0.003 cu (mg/kg) 21.9 102.672 82.3 250.5 60.749 1.087 0 **0.503 ga (mg/kg) 33.6 53.024 53.55 65.1 7.309 -0.662 *0.104 – hg (mg/kg) 0.03 0.314 0.225 1.02 0.256 1.135 0 **0.189 la (mg/kg) 40.7 99.106 93.8 179.3 31.209 0.386 *0.141 – mo (mg/kg) 0.9 9.89 7.55 33.0 7.961 1.125 0 **0.237 nb (mg/kg) 30.7 57.278 59.4 75.4 9.154 –0.774 *0.057 – ni (mg/kg) 88.0 256.76 224.5 1092.0 178.974 3.094 0 0.003 pb (mg/kg) 44.2 103.018 97.6 196.6 33.985 0.828 0.030 **0.842 sc (mg/kg) 35.0 57.5 54.0 91.0 13.239 0.624 *0.096 – sr (mg/kg) 27.6 81.728 74.7 220.4 36.582 1.489 0 **0.240 th (mg/kg) 28.5 45.704 45.25 60.7 6.351 –0.224 *0.496 – u (mg/kg) 4.6 9.076 8.7 26.9 3.565 2.834 0 0.025 v (mg/kg) 286.0 622.24 539.0 1876.0 312.099 1.938 0 **0.064 y (mg/kg) 31.4 85.392 69.7 255.9 45.305 2.163 0 **0.072 zn (mg/kg) 12.0 125.180 90.0 422.0 92.700 1.090 0 **0.340 zr (mg/kg) 312.3 530.06 532.55 721.2 81.161 -0.611 *0.116 – table 2: tests of residual roots (discriminant functions) for both dfms. df eigen value eigen (%) canon. r wilks �� chi2 df plevel major-element dfm 1 2.385 56.93 0.839 0.082 104.9 30 0.000 2 1.067 25.46 0.718 0.278 53.7 18 0.000 3 0.737 17.61 0.651 0.576 23.2 8 0.003 trace-element dfm 1 24.283 79.42 0.980 0.003 208.6 66 0.000 2 5.199 17.00 0.916 0.077 92.3 42 0.000 3 1.094 3.58 0.723 0.477 26.6 20 0.146 geologia croatica 58 geologia croatica 65/1 structure underlying the raw geochemical observations can be easily exposed to the observer. discriminant loadings (simple correlations of variables with respective dfs), or structure coeffi cients, are particularly useful in clarifying the individual contribution of each descriptor variable (major and trace elements), to the overall discrimination. in this sense the variables with small discriminant loadings which contribute little to the explanatory power of dfs in both dfm are seen as irrelevant and can be eliminated from further consideration. this is easi ly seen on the variable diagrams that provide the quickest and most informative insight into the structure of discriminant space, suggesting also which subset of variables (descriptors) most clearly separates the a priori defi ned groups (figs. 2a, 3a and 5a). obviously, elements clustered more or less tightly around the intersection of discriminant axes such as sio2, fe2o3 and na2o in major-element dfm, and the majority of elements in trace-element dfm excluding cr, v, as, ga and some others, do not form the best subset required for meaningful interpretation of dfs in terms of geological processes. association among descriptor variables and related groups is best represented geometrically, viewing the dfs as orthogonal axes intersecting in the reduced discriminant space. however, it is not possible to compare the variable and group scatterplots directly, since different scales are used in each case. the scatterplots of variable loadings (figs. 2a, 3a and 5a) display discriminant axes as normalized vectors, while the scatterplots of canonical means (group centroids), and individual objects (samples), display discriminant score vectors (figs. 2b, 3b and 5b). thus, reciprocity between the variables and groups should always be considered using their shared position along the appropriate axis. 4.1.1. major-element model in the major-element model, all three dfs are highly significant with df1 explaining considerably over half of the total variation (57%) between the groups (tab. 2). as seen from the scatterplot of variable loadings (fig. 2a), df1 is slightly bipolar, primarily separating the istrian group of palaeocene bauxites (ist), from both the central dalmatian (cda) and north dalmatian (nda) groups, while bauxites from the north-adriatic islands (nai) remain largely undistinguished (fig. 2b). the rationale for this separation is founded in the negative association between the k2o–tio2 variable set on the one side and p2o5 on the other. geochemically, it can be understood as ist bauxites being enriched in k2o–tio2 and depleted in p2o5 with regards to nda and cda bauxites, and vice versa. although the overlap is considerable between all groups, a distinct change in content of respective elements can be easily detected if groups are placed in the appropriate palaeogeographic/palaeotectonic setting over the investigated part of adcp. four bauxite groups are regularly scattered in the ist-nai-nda-cda succession following the nw-se strike of the upper cretaceous-paleogene boundary (except in istria where hanging-wall sediments were completely removed). a small but regular decrease in the k2o– tio2 association is easily observable from istria towards central dalmatia (from right to left on the sample-centroid scatterplot, fig. 2b). thus, the geological interpretation of df1 can be established on the “enrichment-depletion” relationship of k2o–tio2/p2o5 variable opposites with reference to their specifi c palaeotectonic setting within the adcp. it must be noted, however, that the central position of the nai bauxites, close to the main centroid and overlapping both ist and cda bauxites, indicates the average major-element composition of a “transitory” group. a general decrease in the k2o–tio2 content in palaeocene (pc) bauxites in a nwse direction, from istria to dalmatia, can be associated with differing palaeographical conditions at various parts of the figure 2: comparison between variables and groups in the major-element dfm: scatterplots of (a) variable loadings and (b) individual objects (samples) in reduced discriminant space of the fi rst two discriminant functions (df1-df2). table 3: multivariate test for overall signifi cance of discrimination. major-element dfm trace-element dfm no. of variables 10 22 wilks lambda 0.082 0.003 approximate f ratio 4.888 6.818 degrees of freedom [30; 109] [66; 75] p-level p < 0.000 p < 0.000 geologia croatica 59 kovačević galović et al.: geochemical discrimination of early palaeogene bauxites in croatia adcp since the cretaceous-paleogene transition (vlahović et al., 2005; korbar, 2009). geodynamic evolution of the external dinarides in post-mesozoic times may have caused a prolonged exposure of primary bauxites, accounting for recurrent contamination by airborne (aeolian dust or volcanic ash), or terrigenous (fl uvial) sedimentary material. due to the extended hiatus lasting in parts of istria from the early cretaceous (shallow-water carbonates) to the early eocene (foraminiferal limestones) (korbar, 2009, and references therein) istrian bauxites (ist) may have been graded and degraded repeatedly due to the input of new material and changing environmental conditions (e.g. discontinued leaching as a result of changing climate or drainage conditions), and thus never deprived completely of clayey (particularly illitic) material. this reworking is advocated by the mineralogical (xrd) analysis showing that only the bauxites from the se part of the dinaridic sw unit (cda) contain gibbsite (hydrargillite), which is the constituent part of the primary bauxites, while other investigated groups (ist+nai+nda) are boehmitic (fig. 4). since the primary (gibbsitic) karst bauxites are rarely preserved in the mediterranean area (hose, 1986), the dehydration of gibbsite into boehmite as an end-product of intensive aluminosilicate weathering in a subtropical environment (palaeosols and recent soils of tropical and subtropical areas) with potentially high leaching rates (herrmann et al., 2007; d’argenio & mindszenty, 1995; kleber et al., 2007) must have been a common process in the most parts of the adcp during the cretaceous-palaeogene transition. however, pc bauxites from the imotski area (cda) are predominantly gibbsitic (fig. 4; tab. 4) indicating prevalently hydrous conditions (intense leaching due to intense rainfall and rapid drainage, chorley et al., 1985) during most of the relatively short emersion stage. mineralogical analysis also demonstrates the absence of anatase as a dominant tio2 polymorph usually present in other groups. the low content of tio2 is characteristic of the cda group while being abundant in the ist and nai (up to 3.88 % in krk-2 sample) together with k2o (fig 2a, b), meaning that at least a portion of the tio2 component must have been enriched by reworking primary bauxites after being formed as fi ne-grained anatase as a result of weathering of the titanium-bearing silicates, similar to recent regoliths (force, 1991). conversely, most of the p2o5 can be co-precipitated with fe-mn oxy-hydroxides (goethite) under oxidative conditions. it is well known that phosphate adsorption by goethite and other fe oxides strongly infl uence its concentrations in soils and aquatic environments (torrent et al., 1992). this interaction must also have been important in controlling phosphate in the bauxite-forming palaeoenvironment. although df1 is generally neutral with regards to fe2o3, the p2o5 content is loosely associated with mno at the negative pole of the function, indicating the possible scavenging role of mn-oxyhydroxides as a proxy channel for phosphorus accumulation in cda bauxites. however, an even closer association of the cao component with p2o5 points to apatite as the main phosphorus phase (fig. 2a). apatite is a widespread accessory phase in the magmatic sequence of ophiolite complexes and is widely documented in literature describing the ni-cr-rich ophiolite-derived laterites of northern greece (e.g. economou-eliopoulos, 2003). not suprisingly, perhaps, the lowest p2o5 concentrations are observed in ist bauxites at the westernmost part of the adcp (commonly below 0.01%; 0.04% in average) far from the dinaridic ophiolite zone. alternatively, high values can be found in all groups (up to 0.11% in nda or 0.10% in nai) indicating that removal of p2o5, more than enrichment was typical for the bauxite-forming environment, being most effective over the istrian peninsula. it is evident from above that df1 can be functionally explained from the perspective of changing environmental figure 3: comparison between variables and groups in the major-element dfm: scatterplots of (c) variable loadings and (d) individual objects (samples) in reduced discriminant space of the fi rst and third discriminant functions (df1-df3). table 4: qualitative mineral composition of the main components in pc bauxites. sample mineral content dr–11 boehmite, haematite, goethite, anatase impc–1 gibbsite, haematite, goethite ipc–7 boehmite, haematite, goethite, anatase krk–4 boehmite, haematite, goethite, anatase geologia croatica 60 geologia croatica 65/1 (palaeogeographical) conditions prevailing during the adcp cretaceous-paleogene emergent phase which resulted in a particular “enrichment-depletion” major-element signature. although statistically highly signifi cant in the majorelement model, the other two discriminant functions df2 and df3 explain a smaller fraction of the total variation (25.5 and 17.6 %, respectively), adding some new insight into the geochemical interpretation of the all-important df1. clarifi cation of df2 revolves primarily about separating the two “inner” groups among the palaeogeographically established ist→cda sequence within the adcp. although not easily observed from the group scatterplot (fig. 2b) it is essential that the “end groups” in this succession (ist vs. cda) do not lose their members to each other (tab. 5). however, df2 separates between nai and nda with extremely high effi ciency in that only one in 20 bauxite samples is lost to other group (nda to nai). discrimination between nda and nai is based on the polarity relationship between the mno– (cao–fe2o3)/mgo major-element suite, which is possibly a refl ection of palaeodynamic and palaeoclimatic conditions prevailing in the central portion of the investigated bauxitebearing croatian high karst area (external dinarides) during the cretaceous-palaeogene transition. the recent hinterland part of the adcp (nda bauxites), can be seen as an ancient repository for the hydrothermally derived marine manganese input from the pelagic realms caused primarily by tectonic/ eustatic changes (corbin et al., 2000, and references therein). in this context the higher manganese content would correspond to a transgressive maximum, whereas the lower content to a regressive maximum. according to chester (1990), almost 90% of continental mn is trapped within coastal and estuarine environments, accounting for periodic ingress of marine waters into terrestrial and lacustrine systems of very low plate-interior relief (d’argenio & mindszenty, 1995). this would explain the elevated content of mno (with fe2o3 and cao) in nda bauxites having occurred immediately before or during the fi nal subsidence of emergent platform areas and subsequent diagenesis of buried bauxite (fe-mn oxy-hydroxides precipitated in oxygen-rich waters). in contrast, the increased content of mgo in nai bauxites may indicate an indurate subaerial setting, characterized by an interim shift to more arid conditions, with limited percolation of meteoric waters in primary bauxites, which results in ineffi cient removal of mg ions and formation of mg-rich clays (ketzer et al., 2003), indicated by an mgo–(tio2–al2o3), as opposed to a mno–(cao– fe2o3) major-element signature, although other scenarios for relative mg-enrichment are possible. the third discriminant function df3 (figs. 3a, b) is essentially monopolar, and it highlights a specifi c major-elefigure 4: x-ray diff ractograms of four early palaeogene bauxite samples from the croatian part of the adcp. geologia croatica 61 kovačević galović et al.: geochemical discrimination of early palaeogene bauxites in croatia ment pattern which is largely concerned with separation of aluminum (al2o3) and titanium oxides (tio2), from the suite of elements including the clayey component from the rest (k2o–sio2–mgo–na2o). accordingly, df3 separates basically on the ground of the clay content in bauxites, with variations (mno, fe2o3), explained earlier as the degree of leaching effi ciency and hydrolysis, and relates most particularly to the cda bauxites. it is thus a supplement to df1, but reveals a distinct gap within the single group dividing most of its members from the primary ist-nai-nda-cda sequence. this separation refers to specifi c conditions in a part of cda bauxitiferous environment distinguished by sluggish removal of leachates, probably due to low amounts of free percolation in waterlogged situations and the occurrence of montmorillonite, illite and chlorite as the resulting clay products (chorley et al., 1985). it must be noted that df3 also reveals some intrinsic heterogeneity within the ist group which probably can be ascribed to changing palaeogeographic and palaeoclimatic changes during the long hiatus, having affected the northernmost portion of adcp. this refers most to ipc-14 where the bauxites, after being reworked, have never been completely leached out (k2o and other clay constituents) but must have undergone conditions of impeded drainage due to periodic rising of the water table (swamps). 4.1.2. trace-element model unlike the major-element dfm only two dfs are statistically signifi cant in the trace-element dfm (tab. 2), of which df1 accounts for almost 80% of the variation between the groups. this model is a clear-cut example of how individual objects can be unambiguously assigned into their a priori defi ned groups (figs. 5a, b). the classifi cation effi ciency is 100%, implying total separation between the four investigated groups of bauxites (tab. 5). this is strongly opposed to the major-element dfm where group division is somewhat blurred, in spite of the same criterion applied in discrimination. the group assignment details based on the squared mahalanobis distance (smd), also show that distances between the groups are considerably larger than in the major-element dfm (tab. 6), with a difference that nda is placed further away from ist (ist/nda = 120.72), than cda (ist/cda = 111.31), modifying the mathematically defi ned geochemical-(palaeo)geographical distance pattern found between the groups in the major-element dfm. comtable 5: classifi cation matrix. predicted groups major-element dfm trace-element dfm observed groups ist nai nda cda total % correct ist nai nda cda total % correct ist 19 1 1 0 21 90.48 21 0 0 0 21 100.0 nai 2 10 0 0 12 83.33 0 12 0 0 12 100.0 nda 0 1 7 0 8 87.50 0 0 8 0 8 100.0 cda 0 1 1 7 9 77.78 0 0 0 9 9 100.0 total 21 13 9 7 50 86.00 21 12 8 9 50 100.0 table 6: squared mahalanobis distance (smd). major-element dfm trace-element dfm group ist nai nda cda ist nai nda cda ist 0.00 0.00 nai 7.54 0.00 18.64 0.00 nda 11.13 10.54 0.00 120.72 94.14 0.00 cda 15.94 10.31 10.11 0.00 111.31 117.54 35.83 0.00 figure 5: comparison between variables and groups in the trace-element dfm: scatterplots of variable loadings (a) and individual objects (samples) (b) in reduced discriminant space of the fi rst two discriminant functions (df1-df2). geologia croatica 62 geologia croatica 65/1 plete/incomplete separation between groups based on the major-element/trace-element signature was observed earlier in similar investigations (peh & halamić, 2010), and can be explained on the grounds that major elements enter various processes active during the sedimentary cycle (from weathering to burial and diagenesis), while accumulation or depletion of trace elements usually narrows the scope of research to some particular segment of the cycle. df1 is essentially a monopolar function and it can be interpreted geochemically as refl ecting a particular position of cr against a number of trace elements with low discriminatory potential, clustered around the main centroid. chromium is typically enriched in ultramafi c and mafi c rocks together with ni although the latter is not so prominent in the analyzed bauxites (fig. 5a). elevated values of cr in bauxites can be indicative of ophiolitic complexes containing ultramafi cs and related rocks as a parent material, particularly given its very low mobility even in strongly-weathered environments, but especially under moderately oxidizing and reducing conditions and near-neutral ph values (de vos et al., 2006). together with other trace elements such as ti and zr in particular, which are considered immobile during weathering and hydrothermal alteration processes (maclean & barret, 1993), the ratios cr forms in bauxites do not differ greatly from those in parent rocks (valeton et al., 1987) and thus can be applied in bivariate or ternary diagrams for determination of the parent material. it is clear from the diagrams (figs. 5a, b) that a clear-cut split between the group pairs caused by cr-enrichment in nda and cda bauxites from the central and se parts of the investigated adcp (high karst dinaridic unit), must suggest an extraneous source of chromium – most probably the dinaridic ophiolite belt with large ultramafi c massif and radiolarite formation (pamić et al., 2002) at the adcp ne border as its host rocks. in contrast, ist and nai bauxite groups of the istrian karst adriatic unit and northern part of the high karst dinaridic unit, respectively, contain below-average cr content. typically, cr-content amounts to 1232 mg/kg in nda or even up to 1424 mg/kg in cda with mean values of 1053 mg/kg and 1142 mg/kg, respectively. this enrichment is considerably higher than that for the majority of mediterranean karst bauxites of various stratigraphic positions including the upper palaeogene (eocene) bauxites from the obrovac area (calagari & abedini, 2007). conversely, ist bauxites contain only 489 mg/kg of cr on average while nai bauxites are slightly more enriched; 556 mg/kg indicating a completely different (felsic) lithological provenance. indicatively, modern soils from north and central dalmatia are highly enriched in chromium (up to 444 mg/kg, obrovac area), being most possibly contaminated by the nearby bauxite deposits, albeit mostly of eocene age, abounding in the area (halamić & miko, 2009). determination of the possible precursor rock type can be easily deduced from the ternary diagram comparing the cr, zr and ga concentration values of palaeocene bauxites formed on the adcp (fig. 6). if compared to corresponding trace-element dfm scatterplots (figs. 5a, b), a striking shift of nda and cda groups to the mafi c and ultramafi c fi eld is obvious drawing these bauxites near to those in bordering bosnia and herzegovina, or even farther east in greece (özlü, 2004; calagari & abedini, 2007, and references therein). apart from chromium, df1 is characterized by smallscale variations in the content of other trace elements and only their relative position with respect to the main centroid indicates slightly elevated concentrations of v, cd and pb (as well as slightly decreased concentration of as, hg and others) in cda and nda groups with respect to ist and nai groups, and vice versa. the second discriminant function df2 is slightly bipolar and contains considerably lower explanatory potential with respect to df1 (only 17%). it is marked by a negative association between as and the suite of trace elements including ga, zr and possibly nb. however, this relationship calls for caution due to commonly weak variable loadings which renders its geological interpretation rather speculative. an inverse relationship between the two trace-element assemblages could be interpreted as representing differing conditions relating to provenance, weathering and deposition during the early stages of bauxite formation, which strongly affect their chemical behaviour. since genesis of primary bauxites in many facets resembles the formation of red claystone and terra rossa soils after the subsequent pedogenesis (merino & banerjee, 2008), it is possible to treat their trace element geochemistry in a similar way as in palaeosols, whether related to weathering intensity, evaluation of leaching, or provenance (sheldon, 2009). elements of interest in this context are undoubtedly zr and nb which are characteristically relatively immobile during figure 6: ternary diagram for zr, cr and ga concentrations in the samples of the four investigated groups of early palaeogene bauxites in croatia; the numbered circles represent the area of infl uence of felsic (1), intermediate (2), mafi c (3) and ultramafi c (4) rocks indicated as probable parent material in genesis of the mediterranean karst bauxites (after özlü, 1983); ucc = average zr-cr-ga content in the upper continental crust (after taylor & mclennan, 1985). geologia croatica 63 kovačević galović et al.: geochemical discrimination of early palaeogene bauxites in croatia weathering of source rocks and bauxite genesis, including ga which is typically related to al and processes of intense leaching, linked with supergene (surface or near-surface) environment under tropical and subtropical climates (hieronymus et al., 2001). as df2 clearly discriminates between the nda-nai group pair set apart by a prominent ga-zr-nb association, and a cda-ist pair characterized by as (figs. 5a, b), this relationship can possibly highlight the redox conditions controlling the trace-element enrichment-depletion in the bauxite-bearing palaeo-environment. arsenic accumulation in subaerially formed sedimentary rocks is most often recognized through the process of sorption on fe oxy-hydroxides, which are precipitated in the form of ooids (goethite) slowly formed under mainly oxic conditions (banning & rüde, 2010). however, lacking precise xrd analysis, the origin of as is ambivalent in spite of possible signifi cant asfe correlation since a variety of processes in the reduced environment may induce co-precipitation of as with fe sulfi des. it is widely believed that sulfi dogenesis via microbial so4 -2 reduction can slow down as mobility in reducing subsurface environments (burton et al., 2011). thus, at least a portion of the as accumulated particularly in istrian bauxites can derive its origin due to precipitation of fe-sulfi de minerals such as pyrite. the presence of sedimentary pyrite in bauxites from minjera (istria) (šinkovec et al., 1994) strongly advocates this possibility. alternatively, as hosted in cda bauxites indicates a different origin, since sulfi des generally do not function as an important sink for lithophile elements such as cr (huerta-diaz and morse, 1992) which abound in cda bauxites. most probably, it is present via the fe-oxyhydroxides (haematite, goethite) derived from the dinaridic ophiolite complex for which as enrichment is well-documented (e.g. in radiolarian cherts, peh & halamić, 2010). conversely, nb, zr, and ga in particular, would indicate hydrous conditions where bases were effectively leached in primary bauxites. that ga is strongly associated with al in this process can be easily deduced by the traceand majorelement dfm comparison (fig. 3a vs. fig. 5a) which both separate the al-ga higher-content nai and nda from lowercontent ist and cda groups. however, an obvious mismatch between the diagrams caused by better separation performed by the trace-element dfm may indicate that al and ga (including zr and nb) do not necessarily follow the same paths controlled by the physico-chemical conditions of the bauxite-bearing environment in all parts of the adcp. it usually calls for reworking the primary (gibbsitic) bauxites since the tight association between al and ga may be disturbed, or even reversed, if gibbsite previously formed by laterization (bauxitization) is later dissolved due to the aforementioned environmental changes. ga, which is more soluble, tends to be leached out, while al migrates downward and precipitates again as gibbsite (hieronymus et al., 2009). this was the probable scenario for distinctive absence of ga (nb, zr) in ist and cda bauxites, although al is enriched only in rare samples of these groups (in the form of gibbsite in cda or boehmite in ist bauxites). 5. concluding remarks two dfms were built in this study in order to distinguish geochemically between the four groups of pc bauxites sampled from the various corners of the croatian part of the adcp. the bauxites, having derived from the same regional unconformity, were assumed to have undergone generally similar conditions of formation with regards to global (eustasy and climate), and regional (volcanism and tectonics) controls during the subaerial exposure of the platform. however, the local portions of emergent palaeoenvironment may have easily experienced a slightly different recombination of controlling factors causing variations in depositional and diagenetic facies (most particularly with regards to the amount of free percolation in the weathering mass), and necessarily variable resulting geochemical signature. high performance of separation between the a priori defi ned groups of bauxites achieved by mda, especially consulting the trace-element dfm, demonstrated a high degree of effi cacy in characterizing specifi c environmental conditions that lead to formation and emplacement of bauxites onto the carbonate platform. important results of mda analysis can be briefl y summarized as follows: – almost complete separation between the four groups of pc bauxites from various parts of adcp (from istria to the central dalmatia) is attained by mda using the geochemical majorand trace-element data array. – the major-element dfm demonstrates a lower degree of separation between groups (86 %) with respect to the traceelement dfm owing to the fact that major elements participate in a variety of processes during the sedimentary cycle resulting in the necessary overlap in the a priori naturally defi ned groups. typically, the best discrimination between the groups is achieved on df1, extracting more than a half of the total variability (57 %) via the bipolar k2o/p2o5 “enrichment-depletion” relationship. this pattern can be identifi ed as signaling the multiple reworking of proto-bauxitic material in changing environmental conditions prevailing during the adcp cretaceous-palaeogene emergent phase. spatially, it is manifested in regular geographical ist-nai-nda-cda succession showing gradual k2o decrease (p2o5 increase) in a se direction. the functions df2 and df3 are of minor importance expounding tectonic/eustatic controls over periodic ingress of marine waters onto the carbonate mainland (mno, nda) or long-lasting subaerial exposure (mgo; nai), and overall degree of maturity characterized by the presence/absence of clay material (enriched al2o3 and tio2 components in majority of groups except for some cda and ist samples), respectively. – trace-element dfm is more suitable for both discriminating and identifying purposes since the classifi cation effi ciency of the established predictive model is the highest possible (100%). discrimination is unequivocally based on cr content which separates the cda-nda (cr-enriched) from the nai-ist group pair, accounting for almost 80% of the explanation potential of df1. this most geologia croatica 64 geologia croatica 65/1 probably refers to the provenance issues relating the source material of cda-nda bauxites to the mafi c precursor rocks from the adjacent dinaridic ophiolite belt. labeling df2 is speculative due to low discriminant loadings but it possibly highlights the redox conditions controlling the trace-element enrichment-depletion in the bauxite-bearing palaeo-environment. acknowledgment this study was supported by the ministry of science, education and sports, republic of croatia (mzoš) – scientifi c project: the map of mineral resources of the republic of croatia. their support is greatly appreciated. the authors are thankful to all who contributed to the execution of this research. a special word of thanks is due tvrtko korbar and miron kovačić who provided us with additional bauxite samples pursuing their own fi eld work within the scope of other mzoš scientifi c projects related to the adriatic (adriatic–dinaric) carbonate platform. finally, this manuscript was greatly improved by the suggestions and the commentaries offered by the reviewers to whom we are deeply indebted. references arrindell, w.a. & van der ende., j. (1985): an empirical test of the utility of the observations-to-variables ratio in factor and components analysis.– appl. psych. meas., 9, 165–178. doi:10.1177/ 014662168500900205 banning, a. & rüde, t.r. (2010): enrichment processes of arsenic in oxidic sedimentary rocks from geochemical and genetic characterization to potential mobility.– water res., 44, 5512–5531. doi:10.1016/j.watres.2010.05.034 bardossy, g. (1982): karst bauxites: bauxite deposits on carbonate rocks.– akadémiai kiadó, budapest, 441 p. burton, e.d., johnston, s.g. & bush, r.t. (2011): microbial sulfi dogenesis in ferrihydrite-rich environments: effects on iron mineralogy and arsenic mobility.– geochim. cosmochim. ac., 75, 3072–3087. doi:10.1016/j.gca.2011.03.001 calagari, a.a. & abedini, a. (2007): geochemical investigations on permo-triassic bauxite horizon at kanisheeteh, east of bukan, west-azarbaidjan, iran.– j. geochem. explor., 94, 1–18. doi:10.1016/ j.gexplo.2007.04.003 chester, r. (1990): marine geochemistry.– unwin hyman, london, 689 p. chorley, r.j., schumm, s.a. & sugden, d.e. (1985): encyclopedia of geomorphology.– routledge publishing, 648 p. corbin, j.c., person, a., iatzoura, a., ferrė, b. & renard, m. (2000): manganese in pelagic carbonates: indication of major tectonic events during the geodynamic evolution of a passive continental margin (the jurassic european margin of the tethys–ligurian sea).– palaeogeogr., palaeoclimat., palaeoecol., 156, 123–138. doi:10.1016/s0031-0182(99)00135-2 croatian geological survey (2009): geološka karta republike hrvatske 1:300.000 [geological map of the republic of croatia 1:300 000 – in croatian].– zagreb. d’argenio, b. & mindszenty, a. (1995): bauxites and related palaeokarst: tectonic and climatic event markers at regional unconformities.– eclogae geol. helv., 88, 453–499. davis, j.c. (1986): statistics and data analysis in geology.– john wiley & sons, new york, 646 p. de vos, w., tarvainen, t. (chief-editors), salminen, r., reeder, s., de vivo, b., demetriades, a., pirc, s., batista, m.j., marsina, k., ottesen, r.-t., o'connor, p.j., bidovec, m., lima, a., siewers, u., smith, b., taylor, h., shaw, r., salpeteur, i., gregorauskiene, v., halamić, j., slaninka, i., lax, k., gravesen, p., birke, m., breward, n., ander, e.l., jordan, g., duris, m., klein, p., locutura, j., bel-lan, a., pasieczna, a., lis, j., mazreku, a., gilucis, a., heitzmann, p., klaver, g. & petersell, v. (2006): geochemical atlas of europe. part 2 – interpretation of geochemical maps, additional tables, figures, maps, and related publications, geological survey of finland, 690 p. dillon, w.r. & goldstein, m. (1984): multivariate analysis: methods and applications.– john wiley & sons, new york, 575 p. doornkamp, j.c. & king, c.a.m. (1971): numerical analysis in geomorphology: an introduction.– edward arnold, london, 368 p. dragičević, i. & velić, i. (2002): the northeastern margin of the adriatic carbonate platform.– geol. croat., 55/2, 185–232. economou-eliopoulos, m. (2003): apatite and mn, zn, co-enriched chromite in ni-laterites of northern greece and their genetic signifi cance.– j. geochem. explor., 80, 41–54. doi:10.1016/s03756742(03)00181-x force, e.r. (1991): geology of titanium-mineral deposits.– gsa spec. pap., 259, 112 p. halamić, j. & miko, s. (2009): geochemical atlas of the republic of croatia.– croatian geological survey, zagreb, 88 p. hose, h.r. (1986): mediterranean karst bauxite genesis and plate tectonics during the mesozoic.– in: 4th international congress for the study of bauxite, alumina and aluminum (icsoba), athens. proceedings, 333–341. hugget, r.j. (1998): soil chronosequences, soil development and soil evolution: a critical review.– catena, 32, 155–172. doi:10.1016/ s0341-8162(98)00053-8 herrmann, l., anongrak, n., zarei, m., schuler, u. & spohrer, k. (2007): factors and processes of gibbsite formation in northern thailand.– catena, 71, 279–291. doi:10.1016/j.catena.2007.01.007 hieronymus, b., kotschoubey, b. & boulègue, j. (2001): gallium behaviour in some contrasting lateritic profi les from cameroon and brasil.– j. geochem. explor., 72, 147–163. doi:10.1016/ s0375-6742(01)00160-1 huerta-diaz, m.a. & morse, j.w. (1992): pyritization of trace metals in anoxic marine sediments.– geochim. cosmochim. ac., 56, 2681–2702. doi:10.1016/0016-7037(92)90353-k ketzer, j.m., morad, s. & amorosi, a. (2003): predictive diagenetic clay-mineral distribution in siliciclastic rocks within a sequence stratigraphic network.– int. assoc. sedimentol. assoc. spec. publ., 34, 43–51. kleber, m., schwendenmann, l., veldkamp, e., rössner, j. & jahn, r. (2007): halloysite versus gibbsite: silicon cycling as a pedogenetic process in two lowland neotropical rain forest soils of la selva, costa rica.– geoderma, 138, 1–11. doi:10.1016/j.geoderma.2006.10.004 korbar, t. (2009): orogenic evolution of the external dinarides in the ne adriatic region: a model constrained by tectonostratigraphy of upper cretaceous to paleogene carbonates.– earth-sci. rev., 96, 296–312. doi:10.1016/j.earscirev.2009.07.004 geologia croatica 65 kovačević galović et al.: geochemical discrimination of early palaeogene bauxites in croatia krumbein, w.c. & greybill, f.a. (1965): an introduction to statistical models in geology.– mcgraw-hill, toronto-london-sydney, 475 p. maclean, w.h. & barrett, t.j. (1993): lithogeochemical techniques using immobile elements.– j. geochem. explor., 48, 109–133. doi:10.1016/0375-6742(93)90002-4 matschullat, j., ottenstein, r. & reimann, c. (2000): geochemical background – can we calculate it?– environ. geol., 39/9, 990–1000. doi:10.1007/s002549900084 matičec, d., vlahović, i., velić, i. & tišljar, j. (1996): eocene limestone overlying lower cretaceous deposits of western istria (croatia): did some parts of present istria form land during the cretaceous?– geol. croat., 49/1, 117–127. merino, e. & banerjee, a. (2008): terra rossa genesis, implications for karst, and eolian dust: a geodynamic thread.– j. geol., 116, 62–75. doi:10.1086/524675 özlü, n. (1983): trace element contents of karst bauxites and their pa rent rocks in the mediterranean belt.– miner. deposita, 18, 469–476. palmer, m.r. (1985): rare earth elements in foraminifera tests.– earth planet. sc. lett., 73, 285–298. doi:10.1016/0012-821x(85)90077-9 pamić, j., tomljenovic, b. & balen, d. (2002): geodynamic and petrogenetic evolution of alpine ophiolites from the central and nw dinarides: an overview.– lithos, 65, 113–142. doi:10.1016/ s0024-4937(02)00162-7 peh, z. & halamić, j. (2010): discriminant function model as a tool for classifi cation of stratigraphically undefi ned radiolarian cherts in ophiolite zones.– j. geochem. explor., 107, 30–38. doi:10.1016/j. gexplo.2010.06.003 phillips, j.d. (1999): earth surface systems: complexity, order, and scale.– blackwell, malden, 180 p. reimann, c. & filzmoser, p. (2000): normal and lognormal data distribution in geochemistry: death of a myth. consequences for the statistical treatment of geochemical and environmental data.– env. geol., 39/9, 1001–1014. doi:10.1007/s002549900081 reimann, c., filzmoser, p. & garret, r.g. (2005): background and threshold: critical comparison of methods of determination.– sci. total environ., 346, 1–16. doi:10.1016/j.scitotenv. 2004.11.023 rock, n.m.s. (1988): lecture notes in earth sciences, 18: numerical geology.– springer verlag, berlin, 427 p. sakač, k., šinkovec, b. & gabrić, a. (1978): geologija i paleogenski boksiti moseć planine (dalmacija, južna hrvatska) [geological setting and bauxites of mt. moseć, dalmatia (south croatia) – in croatian, with an english abstract].– geol. vjesnik, 30/1, 199–218. sakač, k., šinkovec, b., jungwirth, e. & lukšič, b. (1984): opća obilježja geološke građe i ležišta boksita područja imotskog [general characteristics of geological framework and bauxite deposits of imotski area in croatian].– geol. vjesnik, 37, 153–174. sakač, k. & šinkovec, b. (1991): the bauxites of the dinarides.– travaux, 23, 1–12. sheldon, n.d. & tabor, n.j. (2009): quantitative paleoenvironmental and paleoclimatic reconstruction using paleosols.– earthsci. rev., 95, 1–52. doi:10.1016/j.earscirev.2009.03.004 statsoft, inc., 2006. statistica (data analysis software system), version 7.1. www.statsoft.com šebečić, b., palinkaš, l., pavišić, d., šebečić, b. & trutin, m. (1985): bauxite occurrences in the region of zavojane and northwardly of imotski.– geol. vjesnik, 38, 191–213. šinkovec, b. (1973): the origin of early palaeogene bauxites of istria, yugoslavia.– travaux, 3, 151–164. šinkovec, b. & sakač, k. (1981): boksiti starijeg paleogene na otocima sjevernog jadrana [the early paleogene bauxites of north adriatic islands – in croatian, with an english abstract].– geol. vjesnik, 33, 213–225. šinkovec, b. & sakač, k. (1991): bauxite deposits of yugoslavia – the state of the art.– acta geologica hungarica, 34/4, 307–315. šinkovec, b., sakač, k. & durn, g. (1994): pyritized bauxites from minjera, istria, croatia.– nat. croat., 3/1, 41–65. šušnjara, a., sakač, k., gabrić, a. & šinkovec, b. (1990): boksiti područja sinja u srednjoj dalmaciji [bauxites in the sinj area in middle dalmatia in croatian, with an english abstract].– geol. vjesnik, 43, 169–179. tardy, y., trolard, f., eoquin, c. & novikoff, a. (1990): distribution of hydrated and dehydrated minerals in lateritic profi les and landscapes.– in: geochemistry of the earth’s surface and of mineral formation, 2nd international symposium, july, 2–8, 1990, 133–136. taylor, s.r. & mclennan, s.m. (1985): the continental crust: its composition and evolution.– blackwell scientifi c publications, 312 p. tišljar, j., vlahović, i., velić, i. & sokač, b. (2002): carbonate platform megafacies of the jurassic and cretaceous deposits of the karst dinarides.– geol. croat., 55/2, 139–170. valeton, i., biermann, m., reche, r. & rosenberg, f. (1987): genesis of nickel laterites and bauxites in greece during the jurassic and cretaceous, and their relation to ultrabasic parent rocks.– ore geol. rev., 2, 359-404. doi:10.1016/0169-1368(87)90011-4 vlahović, i., tišljar, j., velić, i. & matičec, d. (2002): the karst dinarides are composed of relics of a single mesozoic platform: facts and consequences.– geol. croat., 55/2, 171–183. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeogr., palaeoclimat., palaeoecol., 220, 333–360. doi:10.1016/j.palaeo.2005.01.011 manuscript received august 31, 2011 revised manuscript accepted october 28, 2011 available online february 25, 2012 geologia croatica 66 geologia croatica 65/1  geologia croatica 68/3 273–283 12 figs. 3 tabs. zagreb 2015 geologia croaticageologia croatica abstract modelling spatial variability and uncertainty is a highly challenging subject in soiland geosciences. regression kriging (rk) has several advantages; nevertheless it is not able to model the spatial uncertainty of the target variable. the main aim of this study is to present and test a sequential stochastic simulation approach based on regression kriging (sssrk), which can be used to generate alternative and equally probable realizations in order to model the spatial variability and uncertainty of the target variable; meanwhile the advantages of the rk technique are retained. the sssrk method was tested in a sub-catchment area of the lajvér stream, in southern hungary for the high resolution modelling (i.e. 10 metre grid spacing) of the spatial distribution of soil organic matter (som). in the first step, secondary information was derived according to the soil-forming factors; then the rk system was built up, which provides the base of sssrk. 100 realizations were generated, which reproduced the model statistics and honoured the input dataset. these realizations provide 100 simulated values for each grid node, which is an appropriate number for calculating the cumulative distributions for each grid node. using these cumulative distributions the following maps were derived: the map of the e-type estimation, the corresponding 95% confidence interval width’s map and the map of the probability of the event of {som < 1.5%}. the latter map is highly informative in soil protection and management planning. the resulting model and maps showed that, sssrk is a valuable technique to model and assess the spatial variability and uncertainty of the target variable. furthermore, the comparison of rk and sssrk showed that the sssrk’s e-type estimation and the rk estimation gave almost the same results due to the fairly high r2 value of the regression model (r2=0.809), which decreased the smoothing effect. keywords: geostatistics, regression kriging, sequential stochastic simulation, spatial uncertainty, soil organic matter 1. introduction modelling the spatial distribution, variability and uncertainty of soil related attribute(s) (e.g. soil organic matter content, rooting depth, ph, particle size distribution, bulk density) is a challenging subject in the soiland geosciences, as well as in general environmental research. the resulting model(s) can be applied to support various soil and environmental related decisions, such as delineation of contaminated or endangered zones, estimation of remediation costs, identification areas for fertilization or crop growth and so forth. geostatistics, which can be regarded as a subset of statesting a sequential stochastic simulation method based on regression kriging in a catchment area in southern hungary  gábor szatmári1, károly barta1, andrea farsang1 and lászló pásztor2 1 department of physical geography and geoinformatics, faculty of science and informatics, university of szeged, egyetem u. 2., h-6722 szeged, hungary; (szatmari.gabor.88@gmail.com; barta@geo.u-szeged.hu; farsang@geo.u-szeged.hu) 2 department of environmental informatics, institute for soil sciences and agricultural chemistry, hungarian academy of sciences, herman ottó út 15., h-1022 budapest, hungary; (pasztor@rissac.hu) doi: 10.4154/gc.2015.21 geologia croatica 68/3geologia croatica 274 fication but they were referred to as “deterministic” and “stochastic” approaches. the main aim of this study is to present and test a sequential stochastic simulation method based on regression kriging (sssrk), which is able to generate alternative and equally probable realizations (in order to model the spatial uncertainty) with the constraint that they have to reproduce the model statistics; meanwhile the advantages of rk are retained. sssrk is presented and tested in a sub-catchment area of the lajvér stream in southern hungary, where former soil (water) erosion research has resulted in particular soil sampling and laboratory analysis. the study site is a good example from the point of view of soil science because of the heterogeneous landscapes, where the various effects of soil-forming factors and soil erosion, as well as the various land cover types diversify the sub-catchment soil pattern. soil organic matter (som) content was chosen as a sample variable, being a soil attribute, which has an important role due to its multipurpose functionality in the soiland geosciences, as well as in environmental research. the goal is to build up the high resolution model (i.e. 10 metre grid spacing) of the som spatial distribution based on sssrk. the resulting model and the derived “maps” are of interest for precision agriculture, water erosion and soil protection research, small scale landscape planning and evaluation, integrated catchment management and climate change research (sources and sinks for atmospheric carbon dioxide). 2. study site the sub-catchment (area is approximately 1.32 km2) which drains into the lajvér stream is located in the southern part of hungary, in the szekszárd hills, near the village of szálka (fig. 1). the area of interest is covered by loess-like sediments (dövényi, 2010). the annual precipitation is 650 mm in the study site. the original soil types are cambisols and luvisols with a loamy soil texture, but there are several eroded types of them because of the high relief and the longterm agricultural land use. even regosols can be observed in small areas. however, the eroded soil material forms fluvisols on the valley bottoms. land use more or less conforms to the relief conditions: approximately 50% of the area (65.2 hectares) is used as arable land (see fig. 1), but the steeper slopes are covered by meadows and forests. these latter ones mean mainly acacia but we can see oak forests on the northern part of the sub-catchment. there are new vineyards on the southeastern parts (see fig. 1). 3. materials and methods 3.1. sampling, laboratory measurements and preliminary data analysis former soil (water) erosion research has resulted in a particular pattern of topsoil (0-10 cm depth) sampling and laboratory analyses including som. the database contains 47 records on som content originating from 2 soil profiles and 45 boreholes (fig. 1), sampled in 2008-2009. tistics specialized in analysis and interpretation of geographically referenced data (goovaerts, 1997), provide a huge amount of tools to support these decisions (webster & oliver, 2007). a majority of geographically referenced data (e.g. soil attributes) is related to discrete (sampling) points in the geographic space, which means that we do not have any information about these variables at the unvisited locations. however, an increasing amount of spatially exhaustive secondary information (e.g. digital elevation models, satellite images, geological maps and land cover maps) is available today with increasing spatial and temporal resolution, which can be used in combination with geostatistical tools to satisfy certain requirements (e.g. intrinsic hypothesis, second-order or weak stationarity), and to improve the estimation or simulation models (minasny & mcbratney, 2007). regression kriging (rk) is a representative and widely used technique, which combines the regression of the target variable on spatially exhaustive secondary information with simple kriging of the regression residuals to estimate the value of the target variable at an unvisited location (hengl et al., 2004). rk has several advantages in contrast to other kriging methods, e.g. it can take spatially exhaustive secondary information into account in the estimation process, it can handle the trend (or drift), where the trend term means that the local mean systematically varies from place to place. furthermore, rk is more flexible than kriging with external drift or cokriging methods (simbahan et al., 2006; eldeiry & garcia, 2010; hengl et al., 2003), which also can take secondary information into account in the estimation process. one of the main drawbacks of rk is that it is unable to model the spatial uncertainty or to provide, for example, the 95% confidence interval for the estimates. according to goovaerts (1997), if the intrinsic hypothesis holds, the kriging variance could be used to derive the 95% confidence interval for the estimates. unfortunately, the intrinsic hypothesis is not reasonable to hold in many cases (there is a trend, which makes it unacceptable). the main reason why rk is widely used for spatial modeling is that it can handle the trend (szatmári & barta, 2013). during past decades, stochastic simulations became widespread in the soiland geosciences to model and assess the spatial variability and uncertainty of the target variable(s) (goovaerts, 1997; deutsch & journel, 1998; geiger, 2006; malvić, 2008; novak zelenika & malvić, 2011; geiger, 2012; malvić et al., 2012; novak zelenika et al., 2012). as opposed to any kind of kriging techniques, the main aim of simulation methods is to generate alternative and equally probable realizations, which reproduce the model statistics (e.g. histogram and variogram model), rather than to minimize the local error variance var{z*(u) – z(u)}. hence, simulation methods model the “reality” in a certain global (and not local!) sense, which give an opportunity to model the spatial uncertainty (goovaerts, 1997; deutsch & journel, 1998; geiger, 2006; malvić, 2008). based on this, we can classify the geostatistical techniques into two classes: estimation and simulation methods. malvić (2008) also used this classiszatmári et al.: testing a sequential stochastic simulation method based on regression kriging in a catchment area in southern hungary geologia croatica 275 the topsoil sampling design was planned for modelling the soil erosion process (borcsik et al., 2011). a stratified sampling strategy (supported with geostatistical considerations) was used for this purpose to determine the spatial variability of the eroded and accumulated soil patterns. the land cover (lc) map and the steepness (slope from the digital elevation model; see. fig. 3) of the study area was the basis for the stratification. arable lands are the most seriously affected lc type by soil erosion. hence, this lc type (including the eroded and accumulated soil patterns) had more weights in the sampling strategy than forests and meadows, because the previous lc types are not affected by this soil degradation process (borcsik et al., 2011). as a consequence, arable lands (including the eroded and accumulated soil patterns, as well as the flat valley bottom) are relatively overrepresented; whilst forest and meadows are relatively underrepresented. according to webster & oliver (2007), geostatistical considerations were applied in the sampling strategy to make sure that the sampling design covered the study site uniformly, as far as possible. the soil profiles were excavated; their total depth was 140 cm, where the parent material (loess-like sediments) was reached. the topsoil layer (0-10 cm depth) of the profiles was sampled. a gouge auger was used to excavate the boreholes with an average total depth of 120 cm. the total depths of the boreholes were determined by the depth of the parent material. the samples were collected from the topsoil layer (0-10 cm depth) of the boreholes. the soil profiles and the boreholes were used to characterize the main soil types, as well as the soil erosion process. the laboratory analyses included the determination of som, particle size distribution, ph, bulk density, as well as the carbonate content (borcsik et al., 2011). this study has used the som measurement data according to the hungarian standard (msz 21470-52:1983), which means that som content was determined after sulfuric acid digestion in the presence of 0.33 mol/dm3 potassium dichromate by spectrophotometer (type: helios-gamma). figure 1: the location of the study site in hungary and its land cover presented with the measured soil organic matter (som) data at the sampling points. table 1: summary statistics of the soil organic matter (som) data excluding outliers. statistics value mean 1.600 median 1.531 std. dev. 0.502 minimum 0.768 maximum 3.546 skewness 0.603 kurtosis 0.141 geologia croatica 68/3geologia croatica 276 trend component (also referred to as drift or mean, see goovaerts [1997]) m(u) and a residual component ε(u): ( ) ( ) ( )z m e= +u u u , (eq. 1) where the trend component is accounted for by a multiple linear regression model, whilst the model residuals represent the spatially varying but dependent stochastic component with zero mean, normal distribution (see fig. 2) and covariance structure, which can be modeled with a simple kriging technique. figure 2 presents the schema of rk. based on this, the estimation for z at an unvisited location u0 is given by t t 0 0 0(u ) q (z – q )z = × + ×b l be (eq. 2) where β is the vector of the regression coefficients, q0 is the vector of the secondary information at the unvisited location, λ0 is the vector of the simple kriging weights (assigned to the regression’s residuals), z is the vector of the observations and q is the matrix of the secondary information at the sampling locations. the regression coefficients are estimated by the generalized least squares (gls) method because it is able to take the covariance matrix of the residuals into account along the estimation process. 3.3. spatially exhaustive secondary information for rk in case of soil related attribute(s), secondary information can be compiled according to the soil-forming factors because there is a significant relationship between these factors and the soil attribute(s) (phillips, 1998; mcbratney et al., 2003; bockheim & gennadiyev, 2010; szatmári et al., 2013; bockheim et al., 2014). according to bockheim et al. (2014), the soil-forming factors are the following: topography, climate, parent material, organisms (i.e. vegetation and fauna), the age of the soil and the human intervention, as an anthropogenic factor. only one outlier was identified by box and whisker plot and then it was removed from the raw som data. then summary statistics were calculated for the filtered som data (table 1). figure 1 presents the spatial distribution of the measured som content values. as it was anticipated, the som content is much lower in arable lands and vineyards than in forests and meadows, due to the long-term and intensive agricultural activity, as well as the soil erosion effects, which cause a higher amount of organic matter mineralization, as well as the erosion of the som rich topsoil. as a consequence, the study site shows a diversified picture of the som content’s spatial distribution. these also imply that, the intrinsic hypothesis is not reasonable to hold, because there is an obtrusive trend (i.e. the local mean systematically varies from place to place), which makes several kriging techniques (e.g. ordinary kriging, simple kriging) inappropriate. moreover, the large number of factors (e.g. land cover types, topography, morphometric parameters) and their abrupt changes in the geographic space make cokriging and kriging with external drift techniques inadequate too, according to goovaerts (1997). alternatively, rk is able to handle the trend, as well as it can take numerous secondary information into account considering their abrupt changes in geographic space. hence, the rk technique is a reasonable choice for modeling the som content’s spatial distribution in the area of interest. 3.2. theory of regression kriging (rk) in the last ten years, regression kriging (rk) has been more and more popular to estimate the value(s) of the target variable(s) at unvisited locations taking spatially exhaustive secondary information into account (hengl et al., 2004; simbahan et al., 2006; goovaerts, 2010, 2011; kerry et al., 2012; szatmári & barta, 2013; szatmári et al., 2013; pásztor et al., 2014a, b). rk assumes that the random function z(u) can be deconstructed into a figure 2: the schema of regression kriging. szatmári et al.: testing a sequential stochastic simulation method based on regression kriging in a catchment area in southern hungary geologia croatica 277 climate and parent material can be regarded as homogeneous because of the local aspect of the sub-catchment (dövényi, 2010). unfortunately, we do not have any information about the age of the soils. however, this factor has been frequently omitted in soil related spatial modelling, because it is difficult to characterize well (mcbratney et al., 2003). spatially exhaustive information on topography can be derived from the digital elevation model (dem) of the study area, which was built up with 10 metre resolution. the first step in using this secondary information is morphometric analysis of dem. the derived, so called “morphometric” parameters’ grids are aimed to characterize the geomorphometry of the surface (mcbratney et al., 2003). the grids of the morphometric parameters have the same resolution as dem. table 2 and figure 3 summarize the derived parameters and their characteristics. note that there is a significant relationship between the derived morphometric parameters, thus the “raw” grids of these parameters cannot be used in further multiple linear regression analysis because of multicollinearity. to avoid this, principal component (pc) analysis was performed to transform the grids of the morphometric parameters, because the resultant pc grids are orthogonal and independent. hence, their application decreases the effect of multicollinearity; moreover the resulting pc grids preserve the total variation of the morphometric parameters (geiger, 2007). the pc analysis was carried out in saga gis software with its “spatial and geostatistics / principal components” module, which calculates the pc grids from the input grids. the resulting pc grids were used in further multiple linear regression analysis. spatially exhaustive information on organisms (i.e. vegetation) and human intervention can be derived from the lc map of the study area (fig. 1). in the present case, the lc map was compiled interpreting the products of the official aerial photography campaign of hungary, taken in 2005. as opposed to the morphometric parameters, the lc type is a categorical variable. for the sake of the application of rk, each lc type was converted into an indicator variable (iv). therefore a grid map was generated (with 10 metre resolution) for each lc type with a value domain showing 1 at the locations of the given lc type and showing 0 for all other locations. the resulting ivs were used in further multiple linear regression analysis. figure 3: the maps of the derived morphometric parameters. table 2: the derived morphometric parameters and their characteristics. morphometric parameters characteristics altitude (meter) the vertical distance between the surface and the baltic sea level slope (%) the rise or fall of the surface in percent aspect or slope exposure (degree) the compass direction that a slope faces plan curvature (dimensionless) the curvature of the surface perpendicular to the slope direction profile curvature (dimensionless) the curvature of the surface in the direction of the slope ls (or topographic) factor (dimensionless) quantified effects of slope and slope length on water erosion (wischmeier & smith, 1978) topographic wetness index (dimensionless) quantified control of local topography on hydrological processes, and indicator of the spatial distribution of soil moisture and surface saturation geologia croatica 68/3geologia croatica 278 3.4. theory of sequential stochastic simulation based on regression kriging (sssrk) during previous decades, stochastic simulations became wide spread (goovaerts, 1997; deutsch & journel, 1998; geiger, 2006; malvić, 2008; novak zelenika & malvić, 2011; geiger, 2012; malvić et al., 2012; novak zelenika et al., 2012). these simulations are methods in which alternative and equally probable high resolution models of spatial distribution of z(u) are generated (deutsch & journel, 1998). if the realizations (also referred to as stochastic images) from them honour the input data, then the simulation is called “conditional” (deutsch & journel, 1998). according to goovaerts (1997), let {z(uj), j=1,… ,n} be a set of random variables defined at n locations uj within the study area. the objective is to generate several joint realizations of these n random variables conditional to the dataset. the corresponding n-point (or n-variate) conditional cumulative distribution function (ccdf) is: 1 1 1 1( ,..., ; ,..., | ( )) { ( ) ,..., ( ) | ( )}n n n nf z z n p z z z z n= ≤ ≤u u u u (eq. 3) however, this n-point ccdf can be written as the pro duct of n one-point ccdf: 1 1 1 1 2 2 1 1 ( ,..., ; ,..., | ( )) ( ; | ( 1)) ( ; | ( 2)) ... ( ; | ( 1)) ( ; | ( )) n n n n n n f z z n f u z n n f u z n n f u z n f u z n − − = + − ⋅ + − ⋅ ⋅ + ⋅ u u (eq. 4) where the one-point ccdfs are conditional to the dataset and all previously simulated values. based on this, a stochastic image can be generated in n successive steps (goovaerts, 1997; geiger, 2006): 1. model the ccdf at the first location u1 conditional to the dataset. 2. draw a realization from this ccdf, which realization becomes a conditioning datum for all subsequent drawings. 3. model the ccdf of z(ui) at the ith location (ui) conditional to the dataset and all (i-1) previously simulated values. 4. draw a realization from this ccdf, which realization becomes a conditioning datum for all subsequent drawings. 5. repeat the two previous steps until all n locations are visited and each has been given a simulated value. the resulting set of simulated values represents one realization of the random function over the n locations. other figure 4: a schema of sequential stochastic simulation based on regression kriging. szatmári et al.: testing a sequential stochastic simulation method based on regression kriging in a catchment area in southern hungary geologia croatica 279 realizations are obtained by repeating the entire sequential process with possibly different random path for each realization (goovaerts, 1997; geiger, 2006). when secondary information is available, then this information can be used in the sequential stochastic simulation process (goovaerts, 1997; deutsch & journel, 1998; malvić, 2008). as mentioned above, the secondary information is related to dem and the lc map of the pilot area. in this study, the rk estimation was used to identify the mean of ccdf at any grid node and the simple kriging variance of the residuals was used to identify the variance of ccdf at any grid node, according to goovaerts (1997) and deutsch & journel (1998). figure 4 presents the schema of sssrk. the consequence of this practice is that the variogram and the histogram of the residuals are reproduced by the simulation model. furthermore, the realizations honour the input dataset. in our work, 100 realizations (according to goovaerts [2001] and geiger [2006]) were generated by the previously detailed sssrk method. the resulting stochastic images can be used, for example, to map the e-type estimation, as well as the corresponding upper and lower bound of the confidence interval for each grid node, to assess the spatial uncertainty using the differences between the realizations or to solve tasks like “contouring the probability of the event of {som < 1.5%}” (geiger & mucsi, 2005; geiger, 2006; mucsi, et al. 2013). 4. results and discussion 4.1. results of rk the generalized least squares (gls) method was used to estimate the regression coefficients for the multiple linear regression model. the response variable was the som content, whilst the explanatory variables were the pc grids of the morphometric parameters and the indicator variables (iv) of the lc types. the applied significance level was 0.05 and the “stepwise” method was used to select the explanatory variables into the regression model. table 3 summarizes the results of the multiple linear regression analysis. table 3: results of the multiple linear regression analysis. regression coefficients sig. intercept 1.878 < 2*10-16 explanatory variables pc-1 -0.004 3.08*10-02 pc-2 -0.035 1.20*10-08 pc-4 -0.172 1.29*10-05 iv-forests -0.621 1.63*10-04 iv-vineyards -0.859 5.33*10-08 iv-eroded arables 0.624 3.40*10-05 pc-6 -0.533 1.14*10-02 determination coefficient (r2) 0.809 model p-value 3.59*10-11 seven explanatory variables were selected into the multiple linear regression model by the “stepwise” method (see table 3), where 4 explanatory variables were related to the pc grids (i.e. pc-1, pc-2, pc-4 and pc-6), whilst 3 explanatory variables were related to the iv grids (i.e. iv-forests, iv-vineyards and iv-eroded arables). in case of the selected figure 5: an experimental variogram and the fitted variogram model of the residuals. figure 6: a map of the soil organic matter (som) content created by regression kriging. geologia croatica 68/3geologia croatica 280 pc grids, pc-1 relates to the altitude parameter (i.e. the altitude morphometric parameter had the highest pc coefficient in the pc analysis), pc-2 relates to slope, pc-4 represents the topographic wetness index, whilst pc-6 relates to the ls factor. as a consequence, som spatial distribution is mainly determined by the soil erosion related morphometric parameters and the lc types, as was anticipated. the determination coefficient of the regression model is 0.809 (see table 3), which means that the model explains more than 80% of the total variability of the som data and the remaining approximately 20% have to be modeled with a simple kriging system. the regression residuals were derived and the corresponding experimental variogram was calculated to model their spatial structure (fig. 5). the experimental variogram was approached with a spherical variogram model type with zero nugget, 0.0515 sill (which is approximately 20% of the total variance, see table 1), 204 meter range and isotropic characteristic (see fig. 5). the spatial estimation by rk was carried out using the multiple linear regression model and the fitted variogram model. the rk estimation is presented in fig. 6. 4.2. results of sssrk in this study, 100 equally probable realizations were generated based on the regression kriging system presented earlier and using the sssrk algorithm. figure 7 shows three of the resulting stochastic images of sssrk. as we can see in fig. 7, there are areas where the stochastic images are not so different (e.g. arable lands), whereas we can find some regions (e.g. forests and meadows) where the differences are more pronounced. the experimental variograms of the resulted realizations can be derived and they can be compared with the applied variogram model, which was used in the sssrk process (fig. 8). one of our constraints was that sssrk algorithm has to reproduce, through the resulted realizations, the applied variogram model of the residuals. figure 8 shows that this was achieved. the 100 realizations provide 100 simulated values for each grid node and this number is quite appropriate to calculate the cumulative distribution around an infinitesimally small neighbourhood of each grid node (geiger, 2006; mucsi et al., 2013). using these cumulative distributions the e-type estimation and the corresponding upper and lower boundary of the 95% confidence interval can be calculated for each grid node. moreover, the 95% confidence interval’s width also can be derived, which provides a measure of uncertainty of the som estimation, i.e. when this interval width is relatively high, then the som estimation is more uncertain, according to geiger (2006). figure 9 shows the efigure 7: three realizations of the sequential stochastic simulation based on regression kriging. abbreviation: som: soil organic matter. figure 8: derived variograms from several realizations and the applied variogram model. szatmári et al.: testing a sequential stochastic simulation method based on regression kriging in a catchment area in southern hungary geologia croatica 281 a wider range, than is the case for arable lands. this is in accordance with the aforementioned statements that the e-type estimations are more uncertain in forests and meadows. furthermore, the transect also indicates that the som content is much lower in arable lands, than in forests and meadows, due to the long-term and intensive agricultural activity, as well as the effects of soil erosion, which cause a higher amount of organic matter mineralization, as well as the erosion of the som rich topsoil. at 140 metres along the transect, the range of the simulated values is fairly small, which can be attributed to a sampling point, which is pretty near that grid node (see fig. 1). we can conclude that, the sssrk algorithm honours the input dataset, which was the other constraint on the sssrk technique. in contrast, we can use the calculated cumulative distribution for each grid point to solve tasks like “contouring the probability of the event of {som < 1.5%}”, according to geiger (2006). figure 11 presents that “probability map”, which can be directly used in a soil protection and management plan of the sub-catchment to delineate areas for som archiving. 4.3. comparison of rk estimates with sssrk’s e-type estimates numerous authors have compared the results of the estimation and simulation methods in the last decade, such as goovaerts (2000), geiger (2006), malvić (2008), novak zelenika & malvić (2011), malvić et al. (2012), novak zelenika et al. (2012) or mucsi et al. (2013). following this practice, the results of rk and sssrk were compared. if we compare the rk estimation (fig. 6) with the sssrk’s e-type estimation (fig. 9.a), then we can state that, they are very similar. to test this impression, a difference map was calculated (fig. 12), which quantifies the difference between the map of rk estimation and sssrk’s e-type estimation. the range of the difference map is [0.068; -0.091] (see fig. 12), which is fairly small. based on this, we can conclude that the two maps, from the practical point of view, present the same result. however, we have to notice that this similarity may can be attributed to the fact that the determination coefficient of the regression model is fairly high (r2=0.809), which decreased the smoothing effect of the rk technique (szatmári et al., 2013). 5. conclusions in this paper, a sequential stochastic simulation method based on regression kriging (sssrk) was presented and tested in a sub-catchment area of the lajvér stream, in southern hungary. for this purpose, the soil organic matter (som) content was chosen because this particular soil property has an important role due to its multipurpose applicability. as it was illustrated in this study, sssrk (as opposed to rk) is able to model the spatial uncertainty of the target variable using the generated equally probable realizations (which reproduce the model statistics and honour the input dataset). it is able to provide a measure of the uncertainty of figure 9: the e-type estimation of the soil organic matter content (a) and the corresponding 95% confidence interval width (b) on the basis of 100 realizations. type estimation and the corresponding confidence interval width. as we can see in fig. 9b, the e-type estimations are more uncertain in forests, vineyards and meadows, than in arable lands. it can be attributed to the sampling strategy, which underrepresented the former lc types. a horizontal transect (see fig. 1) was traced out in the northern part of the study site, which intersects the most frequent lc types (arable, meadows and forests). along the transect, the e-type estimation, the upper and lower boundary of the 95% confidence interval and every tenth simulated value were plotted (see fig. 10) in order to analyze how the simulated values vary in different lc types. figure 10 shows clearly that the simulated values in forests and meadows have a) b) geologia croatica 68/3geologia croatica 282 the e-type estimates using the derived confidence interval width. moreover, the calculated cumulative distribution around an infinitesimally small neighbourhood of each grid node can be used to support various decisions (e.g. identification of som rich or som poor areas). in addition, sssrk retained the main advantages of the rk technique such as its flexibility, but it can also handle the trend (or drift) and it can take spatially exhaustive secondary information into account in the simulation process. in conclusion, sssrk is a valuable technique to model the spatial distribution, variability and uncertainty of the target variable and to complete rk’s several shortcomings. figure 11: a map of the probability of the event of {som < 1.5%}. figure 10: horizontal transect of every tenth simulated stochastic image in the northern part of the sub-catchment. figure 12: a difference map of the regression kriging estimation and the sequential stochastic simulation based on regression kriging’s e-type estimation. szatmári et al.: testing a sequential stochastic simulation method based on regression kriging in a catchment area in southern hungary geologia croatica 283 acknowledgement our work has been supported by the hungarian national scientific research foundation (otka, grant no. k105167). references bockheim, j.g. & gennadiyev, a.n. (2010): soil-factorial models and earth-system science: a review.– geoderma, 159, 243–251. bockheim, j.g., gennadiyev, a.n., hartemink, a.e. & brevik, e.c. (2014): soil-forming factors and soil taxonomy.– geoderma, 226–227, 231–237. borcsik, z., farsang, a., barta, k. & kitka, g. (2011): humuszanyagok mennyiségi és minőségi eróziójának mérése a tolna megyei szálka település melletti vízgyűjtőn [quantitative and qualitative measurements of the erosion affected humic material’s distribution in a subcatchment area near village szálka, in tolna county – in hungarian, with an english abstract].– talajvédelem (special issue), 127–137. deutsch, c.v & journel, a.g. (1998): gslib: geostatistical software library and user’s guide.– oxford university press, new york, 369 p. dövényi, z. (ed.) (2010): magyarország kistájainak katasztere [the cadastre of the hungarian small regions – in hungarian].– mta fki, budapest, 876 p. eldeiry, a. & garcia, l. (2010): comparison of ordinary kriging, regression kriging, and cokriging techniques to estimate soil salinity using landsat images.– j. irrig. drain eng., 136/6, 355–364. geiger, j. (2006): szekvenciális gaussi szimuláció az övzátonytestek kisléptékű heterogenitásának modellezésében [sequential gaussian simulation in the modelling of small-scale heterogeneity of point-bars – in hungarian, with an english abstract].– földtani közlöny, 136/4, 527–546. geiger, j. (2007): geomatematika [geomathematics – in hungarian]. – jatepress, szeged, 117 p. geiger, j. (2012): some thoughts on the preand post-processing in sequential gaussian simulation and their effects on reservoir characterization.– in: geiger, j., pál-molnár, e. & malvić, t. (eds.): new horizons in central european geomathematics, geostatistics and geo infor matics.– geolitera, szeged, 17–34. geiger, j. & mucsi, l. (2005): a szekvenciális sztochasztikus szimuláció előnyei a talajvízszint kisléptékű heterogenitásának térképezésében [the advantages of stochastic simulation in mapping the small-scale heterogeneity of water tables – in hungarian, with an english abstract].– hidrológiai közlöny, 85/2, 37–47. goovaerts, p. (1997): geostatistics for natural resources evaluation.– oxford university press, new york, 512 p. goovaerts, p. (2000): estimation or simulation of soil properties? an optimization problem with conflicting criteria.– geoderma, 97, 165–186. goovaerts, p. (2001): geostatistical modelling of uncertainty in soil science.– geoderma, 103, 3–26. goovaerts, p. (2010): combining areal and point data in geostatistical interpolation: applications to soil science and medical geography.– math. geosci., 42, 535–554. goovaerts, p. (2011): a coherent geostatistical approach for combining choropleth map and field data in the spatial interpolation of soil properties.– eur. j. soil sci., 62, 371–380. hengl, t., heuvelink, g.b.m. & stein, a. (2003): comparison of kriging with external drift and regression-kriging (technical report).– international institute for geo-information science and earth observation (itc), enschede, 18 p. hengl, t., heuvelink, g.b.m. & stein, a. (2004): a generic framework for spatial prediction of soil variables based on regression-kriging.– geoderma, 120, 75–93. kerry, r., goovaerts, p., rawlins, b.g. & marchant, b.p. (2012): disaggregation of legacy soil data using area to point kriging for mapping soil organic carbon at the regional scale.– geoderma, 170, 347–358. malvić, t. (2008): kriging, cokriging or stochastical simulations, and the choice between deterministic or sequential approaches.– geol. croat., 61/1, 37–47. malvić, t., novak zelenika, k. & cvetković, m. (2012): indicator vs. gaussian geostatistical methods in sandstone reservoirs – case study from the sava depression, croatia.– in: geiger, j., pál-molnár e. & malvić, t. (eds.): new horizons in central european geomathematics, geostatistics and geoinformatics.– geolitera, szeged, 37–45. mcbratney, a.b., mendonca santos, m.l. & minasny, b. (2003): on digital soil mapping.– geoderma, 117, 3–52. minasny, b. & mcbratney, a.b. (2007): spatial prediction of soil properties using eblup with the matérn covariance function.– geo derma, 140, 324–336. mucsi, l., geiger, j. & malvić, t. (2013): the advantages of using sequential stochastic simulations when mapping small-scale heterogeneities of the groundwater level.– j. en. geo., 6/3–4, 39–47. doi: 10.2478/ jengeo-2013-0005 msz 21470–52:1983 (1983): környezetvédelmi talajvizsgálatok: talajok szervesanyag-tartalmának meghatározása [environmental protection. testing of soils. determination of organic matter – in hungarian].– hungarian standard association, budapest, 4 p. novak zelenika, k. & malvić, t. (2011): stochastic simulations of dependent geological variables in sandstone reservoirs of neogene age: a case study of the kloštar field, sava depression.– geol. croat., 64/2, 173–183. novak zelenika, k., velić, j. & malvić, t. (2012): application of geostatistics in the description of turbiditic depositional environments, a case study of the kloštar field, sava depression, croatia.– in: geiger, j., pál-molnár e. & malvić, t. (eds.): new horizons in central european geomathematics, geostatistics and geoinformatics.– geolitera, szeged, 61–71. pásztor, l., körösparti, j., bozán, cs., laborczi, a. & takács, k. (2014a): spatial risk assessment of hydrological extremities: inland excess water hazard, szabolcs-szatmár-bereg county, hungary.– journal of maps, doi: 10.1080/17445647.2014.954647 pásztor, l., szabó, j., bakacsi, zs., laborczi, a., dobos, e., illés, g. & szatmári, g. (2014b): elaboration of novel, countrywide maps for the satisfaction of recent demands on spatial, soil related information in hungary.– in: arrouays, d., mckenzie, n., hempel, j., richer de forges, a. & mcbratney, a.b. (eds.): global soil map: basis of the global spatial soil information system.– taylor & francis, london, 207–212. phillips, j.d. (1998): on the relations between complex systems and the factorial model of soil formation (with discussion).– geoderma, 86, 1–42. simbahan, g.c., dobermann, a., goovaerts, p., ping, j. & haddix, m.l. (2006): fine-resolution mapping of soil organic carbon based on multivariate secondary data.– geoderma, 132, 471–489. szatmári, g. & barta, k. (2013): csernozjom talajok szervesanyagtartalmának digitalis térképezése erózióval veszélyeztetett mezőföldi területen [digital mapping of the organic matter content of chernozem soils on an area endangered by erosion in the mezőföld region – in hungarian, with an english abstract].– agrokem. talajtan, 62/1, 47–60. szatmári, g., laborczi, a., illés, g. & pásztor, l. (2013): a talajok szervesanyag-készletének nagyléptékű térképezése regresszió krigeléssel zala megye példáján [large-scale mapping of soil organic matter content by regression kriging in zala county – in hungarian, with english abstract].– agrokem. talajtan, 62/2, 219–234. webster, r. & oliver, m.a. (2007): geostatistics for environmental scientists (2nd ed.).– wiley, chichester, 330 p. wischmeier, w.h. & smith, d.d. (1978): predicting rainfall erosion losses: a guide to conservation planning.– u.s. government printing office, washington d.c., 58 p. manuscript received february 16, 2015 revised manuscript accepted july 24, 2015 available online october 31, 2015 ab stra ct the dinaride evaporite mélange is composed of evaporites and associated sedimentary and magmatic formations of permian to triassic age and fl oored by the various adriatic carbonate platform units. the tectonic history of the dinaridic evaporite mélange is related to long term burial and palaeogene to neogene exhumation processes. evaporite rocks of the kosovo polje deposits are associated with carbonates, clastic and minor albitized, subvolcanic, neutral to basic rocks. they are capped by a clayey quaternary cover of variable thickness, and a several metres thick cavernous carbonate breccia-rauhwacke. evaporite rocks show two distinct facies: laminated evaporite-carbonate, composed of evaporite and dolomicrite (± organic matter, pyrite, halite) intercalations, and evaporite-carbonate breccia, composed of fragments of laminated evaporites, carbonate and siltite, cemented by massive gypsum ± sulfur, occurring at the shallower levels and related to the emplacement. the quaternary cover is composed of 47 – 88% clayey material, comprising illite, kaolinite and most likely vermiculite, 9 – 49 % carbonate and 3 – 4% evaporite minerals. the thickness of the evaporite rehydration zone correlates negatively with the thickness of the overlying quater nary cover and with the amount of clayey material within it. rauhwacke are composed of partly dedolomitized dolostone and leached gypsum fragments, cemented with late stage calcite. diagenetic processes are related to early diagenesis and the burial phase began with the formation of diagenetic halite from an oversaturated subsurface or surface (lagoon) brine, and was followed by the biochemical reduction of evaporite sulphate to sulfi de and formation of pyrite within organic-rich carbonate laminae. these processes triggered early dolomitization (in a shallow burial realm), and the formation of idiomorphic planar-e type of dolomite crystals at temperatures below 50 – 60°c. planar dolomite suppressed diagenetic halite. with an increase in burial depth, gypsum dehydrates to anhydrite and when temperatures exceed ~50 °c, precipitation of fi ne grained non-planar-a type of dolomite began. halite molds are partly replaced with non-planar-a type of dolomite. during regional uplift and exhumation, anhydrite rehydrated to gypsum under the infl uence of low-temperature undersaturated fl uid (meteoric water), whereas hydrogen-sulfi de oxi diz ed to elementary sulfur, observed as cement in the evaporite-carbonate breccia. rauhwacke at the uppermost part of the deposit are formed by severe tectonic movements associated with the gypsum-driven dedolomitization process. keywords: evaporite mélange, burial, emplacement, diagenesis, gypsum-anhydrite transition zone, kosovo polje evaporites, dinarides dinaride evaporite mélange: diagenesis of the kosovo polje evaporites  anita kulušić and sibila borojević šoštarić faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, hr-10000 zagreb; (sibila.borojevic-sostaric@rgn.hr; phone: +385-1-4605 800; fax: +385-14836 057) doi: 10.4154/gc.2014.05 geologia croatica 67/1 59–74 12 figs. 2 tabs. zagreb 2014 geologia croaticageologia croatica orites appear as a tectonic mélange in front of the large thrust surfaces. evaporite mélanges of the northern calcareous alps and dinarides are commonly associated with various types of sedimentary, magmatic and metamorphic rocks (spötl & hasenhüttl, 1998; schroll & neubauer, 2013; grandić et al., 2004; borojević-šoštarić & neubauer, 2012). they often preserve various fabrics formed during diagenesis and the fi nal emplacement of the evaporites along the thrust surfaces. 1. introduction during the collisional phase of the orogenic belts, evaporite layers, due to the low shear resistance of the associated minerals, usually control the location of major detachment zones acting as the lubricant for large-scale displacements (e.g. davis & engelder, 1985). in the area of the northern calcareous alps (spötl & hasenhüttl, 1998; schroll & neubauer, 2013), and dinarides (herak, 1973) evapgeologia croatica 67/1geologia croatica 60 a dinaridic evaporite mélange is located in front of the palaeogene to neogene large trusts fronts (fig. 1). this mélange is mainly composed of gypsum and anhydrite associated with various types of sedimentary to magmatic rocks. the age of the evaporites is considered to be permian to triassic by most of the authors (herak, 1973; šušnjara et al., 1992; šiftar, 1986). the tectonic history of the dinaridic evaporite mélange is related to long term burial and palaeogene to neogene exhumation processes. these processes were followed by various types of diagenetic reactions and alteration, transformations and volume changes (warren, 2006 and references therein), including formation of secondary evaporites, dehydratation to rehydratation reactions (gypsum – anhydrite transition), dolomitization to dedolomitization, cementation and precipitation of authigenic minerals such as clays or quartz. all of the listed reactions are highly dependent on temperature, pressure, pore-water geochemistry, water-table level, mineralogical composition and thickness of the overlying deposits as well as the regional uplift rate. in this paper we present a set of mineralogical, petrographical and chemical data from selected drill-cores of the kosovo polje gypsum quarry, knin, croatia. the purpose of this study was to examine the types and intensities of the diagenetic changes related to the emplacement of the koso vo polje evaporite mélange. 2. geological setting 2.1. dinaride evaporite mélange the adriatic carbonate platform represents the most external sector of the dinarides, a southwest-vergent cenozoic orogen to the northeast of the adriatic sea (fig. 1). it is composed of a thick carbonate succession (at some places >8000 m) of middle permian to eocene age (vlahović et al., 2005; pamić et al., 1998 and references therein). onset of deposition of siliciclastic, carbonate and evaporite deposits began with an epeiric type platform, detached from the gondwana supercontinent (i.e. the south tethyan megaplatform; sensu vlahović et al., 2005), and was followed by the late permian to early triassic large-scale tectonic reorganization and intra-plate magmatism (pamić, 1984). the uppermost triassic early to late diagenetic hauptdolomit or dolomia principale represents the latest sequence deposited on the megaplatform, prior to its early jurassic disintegration. carbonate deposition beginning in the middle jurassic, already belongs to the adriatic carbonate platform sensu stricto. based on the geological, petrological, palaeontological, structural and isotope data extracted from previous literature (šćavničar, 1973; pamić, 1984; šušnjara et al., 1992; tišljar, 1992; grandić et al., 2004; vlahović et al., 2005; pamić & balen, 2005; geletti et al., 2008; korbar, 2009) we can summarize the following: (1) evaporites are located in front of the palaeogene to neogene thrust fronts; onshore as an evaporitic mélange (croatia and bosnia and herzegovina), and offshore as diapiric structures in the central and southern part of the adriatic sea (sensu grandić et al., 2004; geletti et al., 2008). (2) the onshore evaporitic mélange is composed of sabkha (tišljar, 1992) type evaporites (gypsum and anhydrite); various types of carbonates (early diagenetic dolostone, lagoonal and intertidal limestone); clastic rocks (siltstone, sandstone and rarely conglomerate); and albitized subvolcanic neutral to basic rocks (pamić, 1984; šušnjara et al., 1992; tišljar, 1992; pa mić & balen, 2005). offshore adriatic diapirs are composed of rock-salt and anhydrite (mattavelli et al., 1991; babić, 1990; spaić, 2012) and neutral to basic subvolcanic to volcanic rocks (palinkaš et al., 2010). (3) onshore evaporites are of late permian to early triassic age, based on palynological analysis (šušnjara et al., 1992) and sulphur isotope analysis of gypsum and anhydrite (šiftar, 1986). recently published data imply that some of the offshore evaporites are of similar age o the onshore evaporites (palinkaš et al., 2010). however, there are different opinions, claiming late triassic, middle-upper jurassic or upper jurassic to cretaceous ages for some of the offshore and drillcore evaporites (e.g. ravni kotari; korbar, 2009; korbar et al., 2009 and references therein). detail palynological analysis (belak et al., 2005; belak & koch 2009) of the offshore vis evaporites gave an assemblage of ladinian to carnian age. ar/ar analyses obtained from the separated plagioclase from nearby jabuka and brusnik insoles gave ages of 227±5 and 219±3ma respectively (de min et al., 2009). several lines of evidence support the argument that permian to triassic deposits exposed on the adriatic carbonate platform represents a tectonic-emplaced evaporite mélange of the dinarides: (1) permian to triassic deposits, composed of evaporites and associated sedimentary and magmatic blocks (tens of metres to hundreds of metres in size), represents a distinct thrust-related formation resting on the younger adriatic carbonate platform units, in front of the palaeogene-neogene thrusts (figs. 1, 2). (2) permian to triassic deposits are exclusively covered by rauchwacke originated by evaporite leaching (tišljar, 1992) and younger quaternary deposits. (3) it is unclear whether gypsum to anhydrite represents an exclusive matrix of the dinaride evaporite mélange since immediate contacts between the permian to triassic rocks and the surrounding evaporites are rarely exposed (sinj location, south adriatic islands; barić, 1969; grandić et al., 2004). (a) however, at some locations, pebbles and fragments of albitzed magmatic rocks occur embedded within the evaporites (barić, 1969) implying their common origin. (b) magmatic rocks usually form morphologically prominent highs within the evaporite valleys (šušnjara et al., 1992) leading to the conclusion that evaporites previously embedding the magmatics, vanished through time. kulušić and borojević šoštarić: dinaride evaporite mélange: diagenesis of the kosovo polje evaporites geologia croatica 61 figure 1: simplified geological map of the dinarides showing distribution of evaporites located in front of the palaeogene to neogene large thrust fronts (simplified after korbar, 2009; schmidt et al., 2008; tomljenović, 2002; gabrić et al., 2002; tišljar, 1992 and šušnjara et al., 1992). therefore, we can summarise the following: a dinaric evaporite mélange is composed of permian to triassic evaporites and associated sedimentary and magmatic blocks (tens of metres to hundreds of metres in size), sometimes embedded within evaporites and thrusted onto the younger adriatic carbonate platform units. most of the dinaride evaporite mélange outcrops are located within karst poljes and valleys such as: vrličko, kninsko, petrovo and drniš karst polje within the lika and dalmatia areas and neighbouring regions in sw bosnia and herzegovina (fig 1). these outcrops are large, economically significant and under exploitation (> 1 mt; gabrić et al., 2002). they are composed of gypsum in the upper part and anhydrite in the lower part, and are covered by rauhwacke and quaternary sediments (mostly clay) of variable thickness. the amount of anhydrite increases with depth, and generally, within the investigated deposits, gypsum occurs within the uppermost 20 – 40 m (gabrić et al., 2002). this is due to partial rehydration of anhydrite to gypsum under the influence of meteoric water related to regional uplift and erosion. 2.2. geology of the kosovo polje kosovo polje is a small size karst field (33 km2) located in the central part of the adriatic carbonate platform at an elevation of 300 – 350 m above sea level. it is surrounded by up to 1000 m-high hills, composed of early triassic to late cretaceous limestone and dolostone, intercalated with clastics at some locations. about 30% of the total kosovo polje surface is represented by late permian to early triassic evaporite mélange units (figs. 2a, b). the evaporite mélange is overlain by quaternary deposits and rauhwacke of variable thickness. the kosovo polje is bounded by thrust faults (herak, 1973) covered by overstep carbonate-clastic flysch sequences; the promina deposits (tišljar, 1992; šušnjara et al.1992). during the exploitation of the evaporite (at mali kukor, veliki kukor, sijećko, bulavato open pits) numerous subvertical to vertical faults were discovered (lukšić et al., 20051), illustrating strong tectonic activity related to the emplacement of the evaporite complex (sensu herak, 1986). extended drilling in this area resulted in over 100 cores with a maximum length of ~70 m (fig. 2b). from twelve 1 lukšić, b., crnogaj, s., dedić, ž. & jurić, a. (2005): report on gypsum reserves of the novo bulatovo and pusto groblje quarries of the kosovo exploitation field.– unpublished report, croatian geological survey, zagreb. geologia croatica 67/1geologia croatica 62 figure 2: (a) simplified geological map of the kosovo polje (after ivanović et al., 1967-1972; grimani et al., 1962-1966; papeš et al., 1968-1980) and (b) lithostratigraphic map of the kosovo karst polje with the positions of the analyzed drill-cores (with permission of the knauf company). representative drill cores, over 70 hand specimens were selected for mineralogical, petrographical and xrd analyses. all of the studied cores display the following successions: (i) quaternary clays, (ii) rauhwacke (not always present) (iii) gypsum zone, (iv) gypsum-anhydrite transition zone and (v) anhydrite zone. geological logs with sample locations are presented in fig. 3. the layey quaternary cover is composed of millimetre to centimetre sized carbonate and evaporite fragments within a predominantly clayey matrix (fig. 4a). cover sediments display variable thickness, from 3.5 to 34 metres, which correlates with the depth of gypsum and the gypsum-anhydrite transition zone. within drill-cores with a thick cover (20 – 30 m), the gypsum zone is only several metres-thick and increases to >50 m with decreasing thickness of the cover deposits. at some locations, the immediate contact with the underlying evaporite is hidden by a <1 – 6 m thick layer of cavernous and sometimes clayey breccia, e.g. rauhwacke. the breccias are composed of various-sized fragments of limestone, dolostone (sometimes dedolomitized) and partially leached gypsum, cemented with calcite and are occasionally cavernous (figs. 4b,c). their origin is related to the leaching of the tectonicallydisrupted evaporites and most likely driven by percolating meteoric water (tišljar, 1992). evaporites show basically two types of macro-facies: (i) laminated evaporite-carbonate facies, composed of millimetre to centimetre gypsum/anhydrite laminae intercalated with dolomite/dolomicrite ± organic matter ± siltite, the dolostone member is usually several times thinner than the sulfate one (figs. 5a,b); and (ii) evaporite-carbonate breccia facies, composed of millimetre to decametre-sized fragments of laminated sulfate, carbonate and siltite cemented by massive gypsum and occasionally sulfur, most likely originating during emplacement (figs. 5c,d; already recognized by tišljar, 1992). an evaporite-carbonate breccia with below 5 vol% of carbonate, prevails in the uppermost levels of the evaporite succession, followed by the laminated facies down dip. kulušić and borojević šoštarić: dinaride evaporite mélange: diagenesis of the kosovo polje evaporites geologia croatica 63 fi gu re 3 : g eo lo gi ca l c ol um ns (d ril l c or es ) o f t he k os ov o po lje e va po rit es w ith s am pl e lo ca tio ns , d is pl ay in g re gu la r s uc ce ss io ns c om po se d of q ua te rn ar y cl ay s, ra uh w ac ke , r eh yd ra tio n zo ne (g yp su m z on e an d gy ps um an hy dr ite tr an si tio n zo ne ) a nd a nh yd rit e zo ne (w ith p er m is si on o f t he k na uf c om pa ny ). geologia croatica 67/1geologia croatica 64 table 1: petrography of the analyzed samples of the kosovo carst polje with marked analysis types. sample no. sample depth (m) petrography carbonate staining xrd kosovo polje carst polje quaternary cover pos-14 ak1 pos-79 ak1 pos-86 ak1 pos-88 ak1 6.00 – 6.50 6.00 – 6.50 1.40 – 1.70 1.00 – 2.00 gy, cal, anhy, q±om gy, cal, q±ms gy, cal, ms±q, om gy, cal, q±ms + + + + rauwacke pos-91 ak2 25.00 – 25.50 gy, cal, do±anhy + evaporites pos-11 ak5 pos-11 ak6 pos-14 ak2 pos-14 ak4 pos-14 ak5 pos-14 ak6 pos-14 ak7 pos-18 ak2 pos-18 ak3 pos-18 ak4 pos-18 ak5 pos-18 ak6 pos-27 ak2 pos-27 ak3 pos-27 ak4 pos-27 ak5 pos-27 ak6 pos-79 ak2 pos-79 ak2a pos-79 ak3 pos-79 ak4 pos-79 ak5 pos-82 ak2 pos-82 ak3 pos-82 ak4 pos-82 ak5 pos-86 ak1c pos-86 ak2 pos-86 ak3 pos-86 ak4 pos-86 ak5 pos-86 ak6 pos-86 ak7 pos-88 ak2 pos-88 ak3 pos-88 ak4 pos-88 ak6 pos-88 ak8 pos-88 ak9 pos-91 ak3 pos-91 ak4 pos-96 ak4 pos-96 ak5 pos-112 ak2 pos-112 ak3 pos-112 ak4 pos-112 ak5 pos-124 ak3 pos-124 ak4 pos-124 ak5 48.00 – 48.40 57.90 – 58.50 21.30 – 21.60 41.55 – 41.75 46.70 – 46.90 55.50 – 56.00 57.30 – 57.60 15.50 – 16.10 21.00 – 21.30 33.20 – 33.60 39.60 – 39.90 46.90 – 47.35 10.20 – 10.50 13.45 – 13.95 23.40 – 23.90 30.30 – 30.60 38.55 – 38.90 19.00 – 19.40 21.80 – 23.00 30.30 – 30.60 38.00 – 38.30 41.63 – 41.77 10.00 – 10.50 19.70 – 20.20 31.00 – 31.50 34.55 – 34.75 15.39 – 15.51 20.54 – 20.90 24.15 – 24.50 25.26 – 25.50 26.30 – 26.60 30.85 – 31.00 35.92 – 36.03 5.20 – 5.62 12.00 – 12.34 26.45 – 26.63 46.34 – 46.68 62.30 – 62.70 66.45 – 66.65 40.40 – 40.70 56.00 – 56.40 16.48 – 16.88 23.50 – 23.75 12.40 – 12.70 18.00 – 18.40 24.00 – 24.20 28.00 – 28.50 38.60 – 39.00 49.20 – 49.60 54.60 – 55.00 gy, anhy, do±om, opq anhy, gy, do±py, om gy, do±anhy, opq,om gy, anhy, do±om, opq anhy, do, gy±om, opq anhy, do, gy±om anhy, do, gy±opq gy, do±anhy±om, opq gy, do±anhy, om, q anhy, gy, do anhy, do±opq anhy, gy, do±opq gy, do±a, opq,om anhy, do, gy±opq, om do, anhy, gy±opq, om anhy, do, gy±opq, om do, anhy, gy±opq, om gy, do, om±anhy,opq gy, do gy, do±anhy gy, do±anhy gy, do±anhy gy, do±anhy, om gy, do gy, anhy, do±om anhy, gy, do±opq gy, do±anhy, opq,q anhy, do, gy±om,opq anhy, gy, do±om, opq gy, do±om, opq gy, do±anhy gy, do±py, anhy, q anhy, do±om, opq gy, do±py, anhy, om gy, do±anhy, opq, om gy, do, anhy±py,om,q gy, anhy±do, om, q gy, anhy±do, om gy, anhy, do, om gy, do±anhy, om anhy, do±gy, om gy, do±om, opq, q gy, do±om, opq gy, anhy, do, om, opq gy, do±om, opq, q anhy, om, do, gy anhy, do, gy±om, opq gy, do±om, opq anhy, do±gy, om, opq anhy, gy, do±om, opq + + + + + + + kulušić and borojević šoštarić: dinaride evaporite mélange: diagenesis of the kosovo polje evaporites geologia croatica 65 3. materials and methods twelve representative drill were selected (from over 100) based on the following criteria: (i) depth of the gypsum, gypsum-anhydrite and anhydrite zones, (ii) associated rocks and macroscopic fabrics, (iii) composition and depth of the overlying deposits and (iv) geographical position of the drill core within the exploitation field. thin sections of evaporite samples from the gypsum, gypsum-anhydrite transition and anhydrite zones, as well as from the overlying rauhwacke deposits of the kosovo polje quarry (n = number of samples; n = 45; table 1) were examined under the optical microscope and analyzed by qwin image analysis software (im 50 v.1.20). fluid inclusions were classified according to the criteria summarized by roedder (1984) and shepherd et al. (1985). in addition, carbonate-rich samples were stained according to evamy & sherman, 1962 (n = 8; table 1) to detect various carbonate minerals. clay mineral analysis of the quaternary cover was performed at the croatian geological survey, zagreb (n = 4; table 1). drill-cores were selected according the apparent thickness of clayey cover; three drill-cores having similar cover thickness, (10 – 16 m being the average cover thickness within the deposit), and a single drill-core with a cover thickness of 34 m. a philips vertical x–ray goniometer (type x‘pert) was used, equipped with cu tube and graphite crystal monochromator with the following experimental conditions: 45 kv, 45 ma, primary beam divergence 1/4º, continuous scan (step 0.002º 2q/s). obtained spectra were analyzed using x׳pert highscore plus 2.1 panalytical b.v. software. selected quaternary samples were analyzed according to the boudine & fernalld (1973) method. after carbonate and sulphate dissolution, orientated fraction <2mm was analyzed 4 times: dry, swelled with ethylene – glycol for 12 hours; heated for ½ an hour at 400°c and at 550°c. clay minerals were determined using a clay mineral identification flow chart. further analyses such as cation-capacity exchange or glycerin swelling is needed for the positive identification of vermiculite. 4. results 4.1. quaternary cover 4.1.1. chemical analysis the amount of evaporite within all the investigated samples is uniform and low (3 – 4 vol %), however, the amount of carbonate is highly variable, ranging from 9 to 49 vol %. eventually, the amount of clayey material ranges from 47 to 88 vol % (table 2). 4.1.2. xrd analysis results of the x-ray diffraction are presented at fig. 6, and indicate the predominance of an illitic component, the presence of kaolinite and probably vermiculite (moore & reynolds, 1997). 4.2. rauhwacke rauhwacke are cavernous carbonate-gypsum breccia usually yellow-brownish in colour. they are composed of up to figure 4: macrophotographs showing (a) clayey quaternary cover composed of millimetre to centimetre sized carbonates and evaporites within predominant clayey matrix; (b) cavernous clayey breccia composed of various-sized fragments of limestone, dolostone (sometimes dedolomitized) and partially leached gypsum, cemented with calcite and (c) cavernous breccia – rauhwacke. table 2: chemical analysis of the quaternary cover samples. sample no. carbonate amount (%) evaporite amount (%) pos 14 ak1 48.8 2.7 pos-79 ak1 49.2 2.8 pos-86 ak1 8.9 3.9 pos-91 ak1 27.5 2.6 geologia croatica 67/1geologia croatica 66 figure 5: macrophotographs showing facies-types of the kosovo polje evaporites: (a, b) laminated evaporite-carbonate facies, composed of millimetre to centimetre gypsum/anhydrite laminas intercalated with dolomite/dolomicrite ± organic matter ± siltite; (b, c) evaporite-carbonate breccia facies, composed of millimetre to decametre-sized fragments of laminated evaporites, carbonate and siltite cemented by massive gypsum. several centimetre-sized carbonate and partially leached gypsum fragments. vugs, cavities and veinlets are partly cemented by late stage calcite (according to evamy and sherman, 1962; fig. 7). purple decorated calcite after staining usually occur as anhedral, coarse grained infill (0.45×0.75 mm in size; figs. 7a, b). dolostone fragments are partly dedolomitized. dedolomite occurs as very-fine grained anhedral crystals, 0.05×0.2 mm in size, usually along previous cracks and veinlets of the fragments (fig. 7a). evaporite fragments are completely rehydrated and sporadically cavernous. 4.3. evaporites 4.3.1. microfabrics microfabric descriptions of the evaporite facies are as follows: (i) laminated evaporite-carbonate facies consist of millimetre – centimetre thick anhydrite to gypsum laminae (up to 80 vol% of total rock) with intercalations of thinly (d<0.2mm – several mm) often disintegrated laminae of fine-grained dolomicrite/ dolomite, organic matter and siltite (up to 20 vol% of total rock; figs. 8a, b). anhydrite regularly appears as nematoblasic and foliated textures, and is often found suppressed by gypsum along the grain boundaries or vinelets (fig. 8c). apart from gypsum and anhydrite, these rocks contain dolomicrite laminae with subordinate amounts of organic matter, pyrite, quartz and rock salt. rock-salt occurs as fine to medium-grained cement, enveloped by organic matter. dolomicrite laminae are often found disintegrated and composed of dolomite kulušić and borojević šoštarić: dinaride evaporite mélange: diagenesis of the kosovo polje evaporites geologia croatica 67 figure 6: results of the x-ray diffraction showing 14å, 10å and 7å peaks interpreted as illite-kaolinite±?vermiculite mixture. crystals of various sizes associated with granoblastic to porphyroblastic gypsum, while the primary laminated structure remains visible (fig. 8d). details of the dolomite classification are given at the end of this section. laminated facies prevail at the deeper levels of the drill-cores, and the amount of anhydrite increases with depth. (ii) evaporite-carbonate breccia is composed of variously sized angular carbonate or laminated evaporite fragments (<5 – 25 vol % of the rock) enclosed within massive gypsum. this type of facies prevails at the shallower levels of the evaporite succession. carbonate fragments are mostly disrupted and composed of tiny dolomite/dolomicrite crystals associated with micron –sized anhydrite and gypsum and crosscut by a network of irregular veinlets filled with fibrous (satin-spar) or granoblastic to porphyroblastic gypsum or anhydrite (figs. 9a, b, d). in geologia croatica 67/1geologia croatica 68 figure 7: photomicrographs of the rauhwacke staining showing (a) very-fine grained anhedral dedolomite crystals along previous cracks and veinlets; (b) anhedral, coarse grained infill of the purple decorated calcite. figure 8: photomicrographs of the laminated evaporite-carbonate facies consisting of (a, b) millimetres centimetres thick anhydrite to gypsum laminae with <0.2mm – several mm thick intercalation of fine-grained, disintegrated dolomicrite/dolomite, organic matter and siltite; (c) nematoblasic and foliated anhydrite suppressed by fibrous gypsum along the grain boundaries or veinlets; (d) gypsum laminae composed of granoblastic to porphyroblastic gypsum, while primary laminated structure remain visible. addition, carbonate fragments sometimes contain organic matter, clays, (? authigenic) quartz or rock salt textural types as chevron fabrics or individual molds overgrown by the coarse-grained gypsum or a-type to e-type dolomite (fig. 9c). fragments of laminated evaporite are carbonate-rich. kulušić and borojević šoštarić: dinaride evaporite mélange: diagenesis of the kosovo polje evaporites geologia croatica 69 figure 9: photomicrographs of the evaporite-carbonate breccia consisting of carbonate or laminated evaporite fragments enclosed within massive gypsum showing: (a, b) mostly disintegrated carbonate fragments composed of micron-sized dolomite/dolomicrite crystals, anhydrite and gypsum crosscut by a network of irregular veinlets filled with fibrous (satin-spar) or granoblastic gypsum to anhydrite; (c) halite mold suppressed by the coarse-grained gypsum and a-type to e-type dolomite; (d) coexistance of granoblastic and porphyroblastic gypsum. classification of dolomite/dolomicrite has been done following the criteria of silbley & gregg (1987). we have observed three dolomite types (fig. 10): (i) fine-grained anhedral dolomite or non-planar-a type of dolomite, <5mm (fig. 10a); (ii) fineto medium-grained subhedral dolomite or planar-s type of dolomite, 5 – 20mm (fig. 10b); and (iii) mediumto coarse-grained euhedral dolomite or planar-e type of dolomite (fig. 10c). non-planar-a type and subhedral-s type of dolomite appears regularly throughout entire evaporite succession, whereas the planar-e type of dolomite prevails at the shallower levels of the evaporite succession, mostly related to the evaporite-carbonate breccia facies. carbonate staining shows evidence of minor dedolomitization at the uppermost levels of the deposit (evamy & sherman, 1962). dedolomites are usually of radial appearance enveloped by randomly orientated fine-grained gypsum (fig. 10d). 4.3.2. fluid inclusion petrography coarse-grained granoblastic to porphyroblastic gypsum contains primary and pseudosecondary monophase, liquid fluid inclusions (according to the criteria of roedder, 1980 and shepherd et al., 1985), located within three-dimensional clusters and subparallel trails within a single crystal, respectively (figs. 11a, b). anhydrite and dolomite do not host visible fluid inclusions. 5. discussion figure 12 presents a model for the evolution of the kosovo polje evaporites, based on the aforementioned data. laminated facies composed of millimetre to centimetre thick intercalations of evaporite and dolostone (sometimes bearing organic matter, pyrite, quartz, halite) were interpreted by tišljar (1992) as having originated from late permian sabkha-type or lagoon-type of the environment. due to burial, the thickness of the overlying deposits increased (i. e. increasing lithostatic pressure and temperature), triggering the onset of the following diagenetic processes: (i) precipitation of secondary diagenetic halite from supersaturated solutions within carbonate, organic rich laminas, (ii) dolomitization and (iii) dehydratation of gypsum. the latter two processes led to strong volume decreases of 12% and 39%, respectively, followed by additional micro-cracking and regeologia croatica 67/1geologia croatica 70 figure 10: photomicrographs of the dolomite/dolomicrite. classification follows criteria according to sibley and gregg (1987): (a) fine-grained anhedral dolomite or non-planar-a type of dolomite; (b) fineto medium-grained subhedral dolomite or planar-s type of dolomite, and (c) mediumto coarsegrained euhedral dolomite or planar-e type of dolomite and (d) bunch-like radial dedolomite enveloped by fine-grained gypsum from the uppermost part of the evaporite sequence. figure 11: fluid inclusion petrography of the coarse-grained granoblastic to porphyroblastic gypsum showing (a, b) three-dimensional clusters and subparallel trails primary and pseudosecondary monophase, liquid fluid inclusions (according to criteria of roedder, 1980 and shepherd et al., 1985). crystallization, especially within the dolomicrite member. severe tectonic movements during the exhumation phase led to the formation of the evaporite-carbonate breccia at the upper parts of the evaporite complex. exhumation processes were followed by widespread rehydratation of gypsum and partial dedolomitization, mainly in the uppermost levels of the deposit. description and clarification of these diagenetic processes is given below. kulušić and borojević šoštarić: dinaride evaporite mélange: diagenesis of the kosovo polje evaporites geologia croatica 71 figure 12: model for the evolution of the kosovo polje evaporites. see text for discussion. 5.1. early diagenesis and burial 5.1.1. diagenetic halite during the evaporation of seawater in the restricted pools or sabkhas, a normal succession would precipitate calcium carbonate, gypsum and halite at a brine concentration of about 1.8, 3.8 and 10.6 times greater than seawater, respectively (mccaffrey et al., 1987). therefore, primary halite laminae or deposits would have to occur superimposed on the gypsum – anhydrite laminae or layers. however, within the kosovo polje deposit, halite is associated with organic-rich dolomicrite/dolomite laminae or fragments and is sometimes overgrown by gypsum and a-type to e-type dolomite. based on their textural characteristics, both types are interpreted as secondary (warren, 2006), and originated from supersaturated subsurface or surface (lagoonal) brines that differ in chemistry and salinity from the primary brines that precipitated carbonate laminae. 5.1.2. dolomitization diagenetic processes in the shallow burial realm are controlled strongly by early dolomitization which is either attributed to the seepage-reflux model (e.g. mattes & conway morris, 1990) or triggered by reducing conditions induced from removal of so4 2by sulphate reducing bacteria (e.g. gingras et al., 2004). according to the seepage-reflux model, dolomitization occures prior to replacement of connate water within permeable carbonates at the lagoon floor with hypersaline, heavy lagoon brine (adams & rhodes, 1960). on the other hand, bacteria induced reducing conditions accompanied by metal enrichment additionally faciliate dolomite precipitation (mirsal & zankl, 1985). these types of processes likely occured within organic-rich, pyriteassociated carbonate laminae of the kosovo polje. the existance of idiomorphic planar-e type dolomite crystals indicates precipitation at temperatures below 50 – 60°c, which again, points to early formation in a shallow burial realm. the predominant non-planar-a type of dolomite/dolomicrite are likely to be related to burial dolomitization at temperatures exceeding ~50°c (sibley & gregg, 1987; warren, 2000). when evaporite successions reach depths of 2-3 km, temperature increases above ~60°c which enables dolomitization by solutions with lower mg/ca ratios. therefore residual evaporite brines or seawater can become dolomitizing solutions (warren, 1999). the amount of non-planar-a type of dolomite generally increases with depth, whereas volumetrically, minor planar-e type of dolomite generally occurs in the uppermost gypsum or gypsum-anhydrite zone. 5.1.3. gypsum dehydration gypsum dehydration begins under similar conditions to dolomitization. when temperatures within the evaporite exceed 60°c (hardie, 1967; jowett et al., 1993; warren, 2006) or the thickness of the overlying deposits exceeds 1000 m (shearman 1995) primary sabhka-type of gypsum will start to dehydrate, leading to the formation of anhydrite. in addition to temperature (and lithostatic pressure), the depth of gypsum to anhydrite transition depends on pore water salinity and pressure and heat flow. under high salinity pore water this transition is plausible at rather low temperatures (t >40°c; yamamoto & kennedy, 1969), whereas overlying conductor rocks imply transition at relatively shallow depths (>400 m; jowett et al., 1993). water liberated via this process is a ca-saturated and halite under saturated brine, escaping into the subjacent evaporite or clastic sediments. this type of brine is most likely responsible for dissolution of halite and formation of molds within the kosovo polje carbonates. dissolution of halite could also occur during regional uplift and flushing of evaporites by meteoric water. 5.1.4. pyrite and sulfur although minor, the occurrence of pyrite within organic rich intercalations of the dolomicrite member and elementary sulfur as cement of the evaporite-carbonate breccia brings us some insight into the geological environment. within the evaporite deposits, metal sulfides and sulfur are formed as the result of the biochemical or thermochemical reduction geologia croatica 67/1geologia croatica 72 of evaporite sulphate to sulfide, followed by oxidation to native sulfur (e.g. machel, 2001; orti et al., 2010; ziegenbalg et al., 2010 and references therein). biochemical reactions include low-temperature (up to 60 – 80°c) bacterial reduction of evaporite sulphate to hydrogen sulfide, whereas thermochemical reactions envisage hydrocarbonsdriven thermal reduction of evaporite sulphate to hydrogen sulfide at temperatures of approximately 100 – 140°c. in both cases, a part of the liberated hydrogen sulfide will rapidly react with available metals, especially fe which is commonly associated with burial sedimentary environments. so4 2removal – metal enrichment processes faciliate dolomite precipitation (mirsal & zankl, 1985). after the system runs out of iron, hydrogen sulfide will oxidize to native sulfur under the influence of meteoric or other oxygenated surface or subsurface waters. within the kosovo polje, pyrite is observed exclusively associated with the organic rich intercalation of the dolomicrite member, implying an active role of organic matter within the reduction process. however, elementary sulfur occurs as cement of the evaporite-carbonate breccia (together with prevailing gypsum) and related to tectonic emplacement of the evaporites, thus indicating late stage hydrogen-sulfide oxidation. maximum burial temperatures of the kosovo polje evaporites are not clear, however, burial history revealed from deep drill-cores (>4500 m) of the nearby ravni kotari antiform imply that the burial temperature of the „alterations of the early-diagenetic dolomite, anhydrite, limestone and argilitic-limestone” did exceed the oil-window (~120°c), at least for the ravni kotari structures (sensu grandić et al., 1997). the absence of saddle (baroque) dolomite from the kosovo polje succession indicates that higher burial conditions (exceeding 60 to 150°c) were not achieved; therefore, low temperature biochemical reduction of evaporite sulphate is more probable. 5.2. emplacement 5.2.1. rehydration rehydration of anhydrite to gypsum occurs during exhumation conditions under the influence of meteoric water. this process led to the formation of granoblastic or porphyroblastic gypsum, volume increase and enterolithic folding, visible at both the micro and macroscales. rehydrated gypsum encloses relics of anhydrite. the fluid inclusion assemblage, discovered within granoblastic to nematoblastic gypsum of the kosovo polje, retains halite undersaturated monophase, liquid-only inclusions, most likely of meteoric-water origin. the width of the rehydration zone (gypsum zone and anhydrite to gypsum transition zone), shows a negative correlation with the thickness of the overlying quaternary cover, as well as with the amount of clayey material within it. drillcores with thick cover (20 – 30m) have a rehydration zone only several metres thick, whereas with decreasing thickness of the cover deposits, the rehydration zone exceeds 50 m in thickness. quaternary cover is composed predominantly of carbonates and illite-kaolinite clayey material with the addition of swelling clay and evaporites (<4 vol %). the carbonate to clay ratio of the quaternary cover also varies strongly, and seems to be related to the thickness of the underlying rehydrated evaporite. within the drill-cores where the cover thickness is similar, clay-rich cover material (> 80 vol % of clays) are underlain by a thin gypsum (<10 m) and anhydrite to gypsum transition zone (<15m), whereas drillcores with a carbonate-rich cover (~50 vol % of clays) display increasing thicknesses of rehydrated evaporates (>30m). formation of fibrous or satinspar gypsum within veinlets, cavities or fractures crosscutting the coarse-grained gypsum and anhydrite of the kosovo polje is most likely to be related to late stage fluid flow. 5.2.2. karstification and dedolomitization formation of rauhwacke subsequent to evaporite rehydration follows when an increased amount of gypsum is leached under the influence of meteoric water from the uppermost evaporite-carbonate breccia. gypsum dissolution processes control and facilitate dissolution of the associated dolomite, followed by calcite precipitation throughout a process described in the literature as gypsum-driven dedolomitization (bischoff et al., 1994 and references therein). the precipitation of calcite removes dolomite-supply carbonate ion and gypsum-supply calcium ion from the solution, thereby causing further dolomite and gypsum dissolution. finally, this type of process, together with tectonic movements resulted in the formation of rauhwacke deposits (several metres thick), on top of the evaporite succession of the kosovo polje. 5.3. correlation with the burrano formation, northern apennines the permian to triassic dinaric evaporite mélange shows notable similarities with the upper triassic burano evaporite formation, located in the northern apennines (secchia river valley; luigi, 2001 and references therein) as follows: (i) the burrano and dinaric evaporite formations are both strongly tectonized sequences with limited vertical and lateral continuity, composed of intercalations of gypsum±anhydrite and boudinage dolostones with minor halite. evaporite-carbonate intercalations of the burano formation are generally thicker (metre to decametre), and interpreted as subaqueous (luigi, 2001) whereas within the dinarides, intercalations appear to be much thinner (millimetre to centimetre), and are considered to be of sabhka origin (tišljar, 1991). in addition, dinaridic dolomicrite laminae contain organic matter, pyrite, quartz and rock salt. (ii) both formations are thrusted onto younger mesozoic formations and interpreted as a main decollement horizon during the oligocene-miocene shortening at the adriatic-dinaric domain. (iii) dinaride evaporites are associated with magmatic and sedimentary rocks, while the burano evaporites are associated with greenshist types of metasediments related to thrusting, and suffered secondary mg-metasomatic replacement with temperatures around 300°c. (iv) due to surface exposure and leaching, both evaporite formations are covered with cavernous dedolomitized breccia-rauhwacke. kulušić and borojević šoštarić: dinaride evaporite mélange: diagenesis of the kosovo polje evaporites geologia croatica 73 6. conclusion evaporite rocks of the kosovo polje deposits are associated with carbonates, clastic and minor albitized subvolcanic neutral to basic rocks and represent a part of the dinaric evaporite mélange. they are capped by clayey quaternary cover and cavernous carbonate breccia – rauhwacke, several metres thick. evaporite rocks show two distinct facies: laminated evaporite-carbonate facies, composed of evaporite and dolomicrite (± organic matter, pyrite, halite) intercalations, related to primary sabhka deposition, and evaporite-carbonate breccia facies, composed of fragments of laminated evaporites, carbonate and siltite, cemented by massive gypsum ± sulfur, occurring at shallower levels and related to the emplacement. quaternary cover is composed of 47 – 88% clayey material, consisting of illite, kaolinite and most likely vermiculite, 9 – 49 % carbonate and 3 – 4% evaporite. the width of the evaporite rehydration zone correlates negatively with the thickness of the overlying quaternary cover and with the amount of clayey material within it. rauhwacke are composed of partly dedolomitized carbonate and leached gypsum fragments, cemented with late stage calcite. diagenetic processes postdating primary sabhka deposition of the evaporite formation are related to early diagenesis, burial and the emplacement phase as follows: · formation of diagenetic halite from oversaturated subsurface or surface (lagoon) brine biochemical reduction of evaporite sulphate to sulfide followed by formation of pyrite within organic-rich carbonate laminas. · early dolomitization in a shallow burial realm within organic-rich, pyrite-associated carbonate laminas controlled by bacteria induced reducing conditions and formation of idiomorphic planar-e type of dolomite crystals at temperatures below 50 – 60°c dissolution of diagenetic halite and formation of molds with planar-e type of dolomite · onset of gypsum dehydration at temperatures of 40 – 60°c · onset of burial dolomitization of carbonate mud at temperature exceeding ~50°c and precipitation of fine grained non-planar-a type of dolomite · replacement of planar-e type of dolomite within molds with a non-planar-a type of dolomite · rehydration of anhydrite to gypsum under the influence of low-temperature undersaturated fluid (meteoric water) · late stage oxidation of hydrogen-sulfide to elementary sulfur, occurring as cement in the evaporite-carbonate breccia · formation of rauhwacke throughout a gypsum-driven dedolomitization process. acknowledgement the knauf company supported the visit of a. kulušić to the drill-core storage in iphofen, germany. authors are grate ful to m. holzapfel, n. stelzer, s. rak, s. lo vri nović and m. putar for logistical help, discussion and their knowledgeable input. the help of nikolina ilijanić in performing xrd analysis at the department of mineral deposits, croatian geological survey is highly appreciated. the authors highly appreciated comments and suggestions of stefano lugli and an anonymus reviewer that clarified the final version of the manuscript. editorial handling by mirko belak. references adams, j.f. & rhodes, m.l. (1960): dolomitization by seepage refluxion.– am. assoc. petrol. geol. bull., 44, 1912–1920. babić, k. (1990): tektonska kretanja i solne strukture u području visbiševo-sušac [tectonic movements and salt structures in the area of vis-biševo-sušac – in croatian with an english abstract].– unpublished ms thesis, faculty of science, university of zagreb, 50 p. barić, lj. (1969): eruptivgesteine (albitisierte diabase) in der umgebung von sinj, dalmatien.– geol. vjesnik 22, 349–410. bischoff, j.l., julia, r., shanks, w.c. & rosenbauer, r.j. (1994): karstification without carbonic acid: bedrock dissolution by gypsum-driven dedolomitization.– geology, 995–998. belak, m., koch, g., grgasović, t., vlahović, i., velić, i., sokač, b. & benček, đ. (2005): novi prinosi stratigrafij i evaporitno-karbonatno-klasatično-vulkanogenog kompleksa komiškog zaljeva (otok vis, hrvatska) [new contribution to the stratigraphy of evaporitic-carbonate-clastic-volcanogenic complex of komiža bay (island of vis, croatia) – in croatian].– in: velić, i., vlahović, i. & biondić, r. (eds.): 3. hrvatski geološki kongres, (3rd croatian geological congress), opatija 29.09.–01.10. 2005., knjiga sažetaka (abstract book), hrvatski geološki institut – croatian geological survey, zagreb, 13–14. belak, m. & georg, k. (2009): evaporitno-karbonatno-klastičnovulkanogeni kompleks (gornji ladinik, karnik – t2 2,t3 1) [evaporitic-carbonate-clastic-volcanogenic complex (upper ladinian, carnian – t2 2,t3 1) – in croatian].– in: velić, i. & vlahović, i (eds): tumač geološke karte republike hrvatske 1:300.000 zagreb, hrvatski geološki institut, p. 38. bodine, m.w., j.r. & fernalld, t. h. (1973): edta dissolution of gypsum, anhydrite, and ca-mg carbonates.– j. sed. petrol., 43, 1152–1156. borojević-šoštarić, s. & neubauer, f. (2012): principle rock types for radioactive waste repositories.– rgn zbornik, 24, 11–18. davis, d.m. & engelder, t. (1985): the role of salt in fold-andthrust belts. tectonophysics, 119, 67–88. de min, a., jourdan, f., marzoli, a., renne, p.r. & juračić m. (2009): the tholeiitic magmatism of jabuka, vis and brusnik islands: a carnian magmatism in the adria plate.– rendiconti online soc. geol. it., 9, 85–87. evamy, b.d. & sherman, d.j. (1962): the application of chemical staining techniques to the study of diagenesis in limestones.– proc. geol. soc., london, 1599, 102. gabrić, a., šinkovec, b., sakač, k. & kuljak, g. (2002): ležišta gipsa u republici hrvatskoj [gypsum deposits of the republic of croatia – in croatian with an english abstract].– rgn zbornik, zagreb 14, 21–36. geletti, r., del ben, a., busetti, m., ramella, r. & volpi, v. (2008): gas seeps linked to salt structures in the central adriatic sea.– basin res., 20/4, 473–487. grandić, s., boromisa-balaš, e. & šušterčić, m. (1997): exploration concept and characteristic of the dinarides stratigraphic and structural model in the croatian offshore area, part 1.– na fta, 4, zagreb, 117–128. grandić, s., kratković, i., kolbah, s. & samaržija, j. (2004): hydrocarbon potential of stratigraphic and structural traps of the ravni kotari area – croatia.– nafta, 55/7–8, 311–327. grimani, i., šikić, k. & šimunić, a. (1962 – 1966): osnovna geološka karta sfrj 1:100000, list knin l33−141 [basic geologgeologia croatica 67/1geologia croatica 74 ical map of sfry 1:100000, knin sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. hardie, l.a. (1967): the gypsum–anhydrite equilibrium at one atmosphere pressure.– am. min., 52, 171–200. herak, m. (1973): some tectonic problems of the evaporitic area in the dinarides of croatia.– geol. vjesnik, 26, 29–40. herak, m. (1986): a new concept of geotectonics of dinarides.– acta geologica, jugosl. akad. znan. i umjet., 16, zagreb, 1–42. ivanović, a., sikirica, v., marković, s. & sakač, k. (1967 – 1972): osnovna geološka karta sfrj 1:100000, list drniš k33−9 [basic geological map of sfry 1:100000, drniš sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. jowett, c.e., cathles, l.m. & davis, b.w. (1993): predicting depths of gypsum dehydration in evaporitic sedimentary basins.– aapg bulletin, 77/3, 402–413. korbar, t. (2009): orogenic evolution of the external dinarides in the ne adriatic region: a model.– earth sci. rev., 96, 296–312. korbar, t., montanari, a., koch, g., mariani, s., depaolo, d., turchyn, a.v., miknić, m. & tari, v. (2009): geologic reconnaissance of the island of velika palagruža (central adriatic, croatia).– geol. croat., 62/2, 75–94. lugli, s. (2001) timing of post-depositional events in the burano formation of the secchia valley (upper triassic, northern apennines), clues from gypsum±anhydrite transitions and carbonate metasomatism.– sedim. geol., 140, 107–122. machel, h.g. (2001): bacterial and thermochemical sulfate reduction in diagenetic settings — old and new insights.– sedim. geol., 140, 143–175. mattavelli, l., novelli, l. & anelli, l. (1991): occurence of hydrocarbons in the adriatic basin.– spec. publ. eapg, 1, 369–380. mattes, b.w. & conway morris, s. (1990): carbonate/evaporite deposition in the late precambrian-early cambrian ara formation of southern oman.– in: robertson, a.h.f., searle, m.p. & ries, a.c. (eds.): the geology and tectonics of the oman region.– geol. soc. london spec. publ., 49, 617–636. mccaffrey, m.a., lazar, b. & holland, h.d. (1987.): the evaporation path of seawater and the coprecipitation of br (super -) and k (super +) with halite.– j. sed. res., 57, 928–937. mirsal, i.a. & zankl, h. (1985): some phenomenological aspects of carbonate geochemistry: the control effect of transition metals.– geol. rundsch., 74, 367–377. moore, d. & reynolds, r.c. (1997): x-ray diffraction and the identification and analysis of clay minerals, 2nd ed.– oxford university press, new york. ortí, f., rosell, l. & anadón, p. (2010): diagenetic gypsum related to sulfur deposits in evaporites (libros gypsum, miocene, ne spain).– sedim. geol., 228, 304–318. palinkaš, l.a., borojević šoštarić, s., strmić palinkaš, s., crnjaković, m., neubauer, f., molnar, f. & bermanec, v. (2010): volcanoes in the adriatic sea: permo-triassic magmatism on the adriatic-dinaridic carbonate platform.– acta mineral. petrogr., 8, 1–15. pamić, j. (1984): triassic magmatism of the dinarides in yugoslavia.– tectonophysics, 109, 273–307. pamić, j. & balen, d. (2005): interaction between permo-triassic rifting, magmatism and initiation of the adriatic-dinaridic carbonate platform (adcp).– acta geol. hung., 48/2, 181–204. pamić, j., gušić, i. & jelaska, v. (1998): geodynamic evolution of the central dinarides.– tectonophysics, 297, 251–268. papeš, j., marinkovič, r., raić, v., magaš, n. & sikirica, v. (1968-1980): osnovna geološka karta sfrj 1:100000, list sinj k33−10 [basic geological map of sfry 1:100000, sinj sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. roedder, e. (1984): fluid inclusions.– mineral. soc. amer., rev. mineral., washington, 12, 644 p. šćavničar, b. (1973): halite molds within clastite from vrlika and knin area.– geol. vjesnik, 26, 155–157. schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine-carpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss j. geosci., 101, 139–183. schroll, a. & neubauer, f. (2013): emplacement of an evaporitic mélange nappe in central northern calcareous alps: evidence from the moosegg klippe (austria).– austrian j. earth sci., 104/2, 22–46. sheperd, t.j., rankin, a.h. & alderton, d.h.m. (1985): a practical guide to fluid inclusion studies.– blackie & son ltd., glasgow, 239 p. sibley, d.f. & gregg, j.m. (1987): classification of dolomite rock textures.– j. sedim. petrol., 57, 967–975. spötl, ch. & hasenhüttl, ch. (1998): thermal history of the evaporitic haselgebirge mélange in the northern calcareous alps (austria).– geol. rundschau, 87, 449–460. šiftar, d. (1986): starost evaporita u području sinj–gornji tok une.– geol. vjesnik, zagreb, 39, 55–60. spaić, v. (2012): oil and gas bearingness and structural elements of adriatic islands and peninsulas (outer dinarides) with special review of anhydrite – carbonate mesozoic complex and diapiric belt.– nafta, 63/1–2, 29–37. šušnjara, a., sakač, k., jelen, b. & gabrić, a. (1992): upper permian evaporites and associated rocks of dalmatia and borderline area of lika and bosnia.– geol. croatica, 45, 95–114. tišljar, j. (1992): origin and depositional environments of the evaporitic and carbonate complex (upper permian) from the central part of the dinarides (southern croatia and westen bosnia).– geol. croatica, 45, 115–126. tomljenović, b. (2002): strukturne karakteristike medvednice i samoborskog gorja [structural characteristics of the mt. medvednica and the samoborsko gorje mt. – in croatian with an english abstract].– unpublished phd thesis, faculty of mining, geology and petroleum engineering, university of zagreb, 208 p. vlahović, i., tišljar, j., velic, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeo., palaeo., palaeo., 220/3–4, 333–360. warren, j. (1999): evaporites: their evolution and economics.– blackwell science, oxford, uk, 438 p. warren, j. (2000): dolomite: occurrence, evolution and economically important associations.– earth-sci. rev., 52, 1–81. warren, j. (2006): evaporites: sediments, resources and hydrocarbons. – isbn 3-540-26011-0 springer berlin heidelberg new york, 1041. yamamoto, h. & kennedy, g.c. (1969): stability relations in the system caso4-h2o at high temperatures and pressures.– am. j. sci., 267a, 550–557. ziegenbalg, s.b., brunner, b., rouchy, j.m., birgel, d., pierre, c., böttcher, m.e., caruso, a., immenhauser, a. & peckmann, j. (2010): formation of secondary carbonates and native sulphur in sulphate-rich messinian strata, sicily.– sedim. geol., 227, 37–50. manuscript received july 11, 2013 revised manuscript accepted march 05, 2014 available online march 21, 2014 08 garasic.indd garašić and jurković: geochemical characteristics of diff erent iron ore types from the southern tomašica deposit, ljubija, nw bosnia 255 � ab stra ct pulverized limonite ore from a pleistocene–quaternary lake deposit and compact limonite ore from the olistostrome member of the javorik fl ysch formation, in the southern tomašica iron ore deposit, were investigated and compared with different types of siderite and ankerite, limestone and carbonate shale from the same location in order to determine their possible protolith. two limonite types display a notably distinct ree pattern, ree fractionations, eu anomalies and other trace element and main oxide content. the ree pattern of compact limonite is characterized by relatively low light ((la/sm)n = 2.87), heavy ((gd/yb)n = 0.98) and total ((la/yb)n = 3.19) ree fractionations, a strong positive eu anomaly (eu/eu* = 2.11) and weakly expressed negative ce anomaly (ce/ce* = 0.82). the compact limonite and siderite ree patterns almost overlap suggesting a common ree source. the same is valid for their zr/tio2 ratios (0.040 in the compact limonite, 0.033–0.053 in the siderites). pulverized limonite shows remarkably different ree patterns and the highest ree concentrations, (up to 6 to 13 times higher relatively to the other samples). its ree fractionation pattern ((la/sm)n = 3.68, (gd/yb)n = 1.58, (la/yb)n = 9.41, eu/eu* = 1.10 and ce/ce* = 0.81) is very similar to those in the carbonate shale, identifying it as the possible protolith of pulverized limonite. the same is valid for the zr/tio2 ratios (0.025 in pulverized limonite and 0.017 in carbonate shale). the ree pattern of fi ne grained ankerite ((la/yb)n = 2.15, eu/eu* = 1.95, ce/ce* = 0.78) and its zr/tio2 ratio (0.030) are similar to those in siderite, and could, assuming extensive contamination of pulverized limonite, also represent its protolith. however, the ree patterns of coarse grained ankerite exhibit remarkable depletion of lree over hree and a strong reverse lree pattern ((la/yb)n =0.05–0.20, (la/sm)n = 0.04–0.10, (gd/yb)n = 1.77–1.91). they have (similar to the other studied samples), a positive eu anomaly (eu/eu* = 2.16–2.75) and negative ce anomaly (ce/ce* = 0.32–0.83). their zr/tio2 ratio (0.004–0.010) excludes coarse grained ankerite as the possible protolith of pulverized limonite. keywords: compact limonite, pulverized limonite, ree pattern, siderite, ankerite, southern tomašica geochemical characteristics of diff erent iron ore types from the southern tomašica deposit, ljubija, nw bosnia � vesnica garašić and ivan jurković faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, hr-10000, croatia; (vesnica.garasic@rgn.hr) doi: 104154/gc.2012.16 geologia croatica 65/2 255–270 21 figs. 3 tabs. zagreb 2012 geologia croaticageologia croatica 1. introduction southern tomašica is one of the four opencast mines (adamuša, vidrenjak, tomašica and omarska) in the ljubija iron ore fi eld, situated approximately 200 km northwest of sarajevo, in bosnia and herzegovina. southern tomašica is a large deposit of siderite, ankerite, compact limonite and pulverized limonite laying 18 km southeast of prijedor. it is located on the northern side of the mountain system of ljepovica (+678 m) and mačkovac (+474 m) and bordered to the west by the velika gradina plateau (fig. 1). geologia croatica 65/2geologia croatica 256 the origin and time of formation of the iron deposits in the ljubija iron ore fi eld are matters of considerable debate. grubić & protić (2003) clearly distinguishes an older siderite-limonite formation and a younger ankerite-limonite formation. according to them, siderite occurring as lenses and alternating with black argillaceous schist in the sideritelimonite formation, originated as primary non-magmatic hydrothermal marine sediment in the lower to middle carboniferous. the fi rst evidence of the synsedimentary origin of this siderite was provided by jurković (1961). jurić (1971) shared the same opinion. grubić & protić (2003) discovered fi ssures fi lled with iron and manganese minerals in upper flysch, permian and werfenian sediments of southern tomašica. therefore they concluded that ankerite replacing carbonate rock fragments in fl ysch and small siderite bodies, associated with the carbonate olistoliths in the olistostrome member of the javorik fl ysch formation, was precipitated from hydrothermal solutions partly associated with porphyrite volcanism in the middle triassic. strmić palinkaš et al. (2009) regarded iron deposits within the ljubija fi eld as stratabound fe carbonate ore bodies, hosted by marine limestones, and as siderite-sulfi de veins within carboniferous shales. they concluded that fe mineralization occured through hydrothermal-metasomatic processes in the permian, in accordance with the earlier opinions of pa linkaš (1988, 1990), palinkaš et al. (2003) and boro jević šoštarić (2004). figure 1: the location of the studied area. later in geological time, siderite and ankerite ore bodies were partly oxidized and hydrated to various types of limonite ore (jurković, 1961; jurić, 1971; grubić & protić, 2003). although the mineralogy and major element chemistry of different limonite ore types from the southern tomašica mine have been described earlier (jurković, 1961; šarac, 1981), their ree patterns are still unknown. the aims of this study are to present the results of more detailed geochemical analyses for two different limonite ore types and compare them with the ree distribution patterns of ankerite, siderite, host limestone and carbonate shale, from the olistostrome member of the javorik fl ysch formation, in order to establish their possible genetic relationships. 2. geological setting the area of southern tomašica consists mainly of sedimentary rocks of carboniferous, permian, werfenian and quaternary age (fig. 2), which were metamorphosed, folded and faulted during the variscan and alpine orogenies (fig. 3). carboniferous rocks belong to the javorik fl ysch formation, and the permian rocks to the tomašica clastite formation. the most detailed stratigraphic column of this area was drawn by grubić et al. (2000) and grubić & protić (2003) on the basis of fi eld work (m 1:1000) and core descriptions from 520 wells (fig. 4). according to grubić & protić (2003) the javorik fl ysch formation consists of six members. the oldest member is the lower flysch characterized by dark green argillaceous schists, alternating with medium-grained sandstone. it is followed by the sideritelimonite member which is up to 30 m thick, becoming thinner at the margins. this member contains massive siderite alternating with black argillaceous schist. siderite is partly transformed to limonite. the wild flysch member, (<50 m thick), overlies the siderite-limonite member. it consists of two black argillaceous phyllite packets and one sandstone packet. it exhibits characteristic spheroidal and tube-like olistolithes at the decimetre-level on the surface. the wild flysch member is overlain by the middle flysch member which is about 60 m in thickness, consisting of alternations of argillaceous schist, (subfl ysch), sandstone (argillaceous eufl ysch) and sandstone (coarse fl ysch). it contains variably sized olistostrome lenses with mineralized limestone fragments, sandstone banks and rare microconglomeratic sequences. the middle flysch member is overlain by an olistostrome member, which is 800 m long and 50 to 150 m wide, consisting of fl ysch matrix in which carbonate olistolithe fragments, blocks and their mineralized parts are embedded. the flysch groundmass of the olistostrome member is mainly sandstone fl ysch, the lower and upper parts of which are composed of grey and dark grey medium-grained sandstones, and black laminated siltstones, respectively. carbonate fragments and blocks of the olistostrome member include black micrites, dark grey organogenic sparites (rich in fossils), dolomite limestones, dolomites, ankeritic limestone and ankerite. the occurrence of pulverized limonite, which in larger blocks represents the transition from ankerite and garašić and jurković: geochemical characteristics of diff erent iron ore types from the southern tomašica deposit, ljubija, nw bosnia geologia croatica 257 figure 2: geological units of the tomašica area (grubić & protić, 2003). figure 3: geological profi le i-i’ (fig. 2) of southern tomašica (grubić & protić, 2003). sampling locations are marked. dolomite limestones into fossiloferous limestones, is important. typically, up to 3–4 m large isolated, spheroidal and irregular bodies of partly comb-textured ankerite and dolomite limestone, completely enclosed by pulverized limonite occur in this member. they appear in groups of several bodies in pulverized limonite profi les having a thickness of several tens of metres. in addition to this description of grubić & protić (2003), strmić palinkaš et al. (2009) discovered in the olistostrome member, dark massive siderite being locally weathered to porous, but compact limonite, while the present authors observed numerous dark limestones cut by veins of siderite, ankerite and calcite. in the geologia croatica 65/2geologia croatica 258 fl ysch groundmass of the olistostrome member, carbonate shale occurs as a small isolated body. according to grubić & protić (2003), the last and the youngest member of the javorik formation is the upper flysch, being located on the northern side of the opencast. it is 700 m long, 140 m wide and 70 m thick. the lower part of this member is particularly black in colour, and mostly composed of sandstone-siltstone fl ysch. the black colour comes from mn oxides and hydroxides, and is more weakly expressed in the upper part, where sequences are at the centimetre scale. the tomašica clastite formation is located on the western side of the opencast mine, in the area of velika gradina. grubić & protić (2003) recognized fi ve members of this formation: a) bobovica breccias, b) white sandstones, c) white and red sandstones, d) polygenous conglomerates and e) red sandstones and siltstones. the southern part of the southern tomašica opencast mine consists of marls, marl limestone, siltstones, sandstones and breccia-like intercalations of werfenian age, which reach a thickness of around 70 m. according to jurić (1967) and podubski (1969), the rocks of the javorik formations are metamorphosed at the highest grade of the greenschists facies. during the tertiary, after uplift of the upper palaeozoic complex, the oxidation processes of primary iron ore (siderite, ankerite and ankeritized carbonate rocks) in ljubija had begun and limonite gossans had been formed “in situ”. according to jurković (1961), gossans developed by weathering of siderite were compact and stable, while those derived from massive ankerite were more mobile. later, due to erosion, gravity, mechanical and chemical leaching and solution, different aureoles of secondary limonite ore were developed. in the pliocene–quaternary period remarkable part of this limonites were further transported by rain, river or wind, and redeposited in palaeovalleys, palaeobasins and lakes, partly as detrital limonite, partly as pulverized limonite or “brand” (termed by jurković in publications). on this occasion limonites became more or less contaminated. reworked deposits of limonites and pulverized limonites in the pliocene–quaternary sequences of jezero and buvač near omarska were described by jurić (1969) and šaracvitaljić (1973), and those in the blatnjak deposit by jurić (1971). the best description of reworked deposits of limonite and pulverized limonite in the area of tomašica (southern tomašica, northern tomašica, šiljezi, stankovići, dabića brdo, tevanovići, bojići) was by cvijić (1986, 2001). the ore bodies are mainly characterized by lense-like or conelike shapes, rarely irregular layers, reaching thicknesses of 10–30 m, locally up to 50 m, rarely more than this. the borders of ore bodies are not sharp. 3. previous studies of limonites in tomašica laboratory and commercial studies by logomerac (1960) have shown that pulverized limonite is a suitable oregrade raw material for sintering, pelletizing and bricketizing in the production of raw iron. the granulometric composition of pulverized limonite was characterized by 26.8 wt.% of particles fi ner than 60 μm, 46.8 wt.% of particles ranging between 60 and 100 μm, 16.3 wt.% of particles laying between 100 and 400 μm and 10.0 wt.% of particles from 400 to 1500 μm diameter. the specifi c and volume weights were 3.3 g/cm3, and 1.38 g/cm3, respectively. the loi was equal to 8.15% and h2o– to 6.8%. the fi rst laboratory, physico-chemical and optical studies of limonite samples from the southern tomašica ore district (točak, gradina, stojančići and klimenta localities) were performed by jurković (1961). the xrd analyses of pulverized limonite (brand) from stojančići show mostly the presence of micro-cryptocrystallized goethite (70 wt.%), and some amorphous clay, having no peaks on the debye diagram. dta has given endothermic effects, which were strong at +200°c (goethite) and 350°c (partly amorphous limonite) and weak at temperatures from +550°c to +650°c (clay). tga shows weight loss of 8% in the range between +100°c and +400°c (goethite-limonite), and 4 % between +550°c and +650°c (illite clay). the results of xrd, dta and tg analyses reveal that the brand consists of a mixture figure 4: stratigraphic column of southern tomašica (grubić & protić, 2003). garašić and jurković: geochemical characteristics of diff erent iron ore types from the southern tomašica deposit, ljubija, nw bosnia geologia croatica 259 of cryptocrystalline and partly amorphous goethite and allophanoid amorphous clay (68.25 and 8.65 wt.% respectively). the studied sample was prepared in plexiglas and investigated under refl ected light microscopy (fig. 5). pulverized limonite (brand) consists of pizoliths having diameters in the range of 30 and 300 μm, on average between 100 and 200 μm. pizoliths are spheroidal, rarely oval and consist of an intimate mixture of cryptocrystalline goethite and amor phous or cryptocrystalline clay masses. in refl ected light they have considerably lower lustre than goethite, are isotropic, and in crossed polars show diffusely scattered brown inner refl ections. šarac (1981) analyzed pulverised limonite samples, discovering a very high content of sio2 (15.56%) and al2o3 (3.40%) compared to compact limonite. studies in the boris kidrič institute in ljubljana and in firma bayer have shown that ore deposits of pulverised limonite in tomašica represent a natural mineral pigment with a high content of natural chromofore (up to 80 %) which is applicable to the colour and varnish industry and in the industry of anticorrosive coating and coloured building materials. on the basis of these studies, a natural pigments factory was built in tomašica using pulverised limonite raw material from the southern tomašica deposit and the blatnjak deposit. detailed petrological characteristics of compact limonite have been described by jurković (1961). using xrd analyses, he identifi ed goethite as the main mineral intimately intergrown with illite which has sheets up to 10, and rarely up to 30 μm or more and with quartz crystals, occurring in bipyramidal prisms, with diameters in the range between 30 and 300 μm, or in alotriomorphic masses. there are oxidized pyrite relics and minor lepidocrocite in massive goethite. additionally, fi ne microscopic tiny veinlets of cryptocrystalline pyrolusite and microcrystalline pyrolusite in pores are also present in goethite. cryptocrystalline or fi brous psilomelane also occur replacing goethite or being transformed into pyrolusite. the manganese minerals were most likely formed as a weathering product of siderite, which contains up to 2.55 wt.% of mno. elemental silver was observed in the goethite pores. mineral intergrowths are frequent and fi ne-grained, or rare and coarse-grained. 3.1. samples and analytical methods all samples were collected within the olistostrome member of the javorik fl ysch formation excluding pulverized limonite (tbra) which was found on an ancient mine heap at stojančići representing relics of one pleistocene–quaternary lake limonite deposit. levels of the quarry containing the siderite-limonite member have been submerged some years ago since mining operations ceased and it was impossible to collect samples from this part of the javorik fl ysch formation. ten representative samples from the southern tomašica opencast mine and one from the adamuša opencast mine have been studied in detail: compact limonite (tlim) representing gossan formed in situ on siderite, pulverized limonite or “brand” (tbra), limestone (tvap1), carbonate shale (tvap2), white-gray coloured ankerite (tmix), white coarse grained ankerite (tank, tanmic), dark fi ne grained ankerite (tank1), reddish coarse grained siderite (tcor), dark fi ne-grained siderite (tmic) and yellow coarse grained siderite (ad-2). the sample of compact limonite (tlim) represents a gossan formed “in situ” on siderite. it occurs in the form of black and shiny, kidney shaped concretions, and glassy needles (fig. 6). microscopic investigations show that the concretions have an internal radiating structure (fig. 7) and the main mineral is goethite. other minerals in the paragenesis are quartz, clay minerals and muscovite. this is in accordfigure 5: spheroidal pizoliths consist of a mixture of cryptocrystalline goethite and amorphous or cryptocrystalline clay. white thin intergranular fi lms of cryptoto microcrystalline goethite surround the pizolites. the black area is a hole. magnifi cation: x55 (after jurković, 1961). figure 6: black and shiny kidney shaped concretions and glassy needles in compact limonite (sample tlim). geologia croatica 65/2geologia croatica 260 ance with the former more specifi c petrographic investigations of compact limonites performed by jurković (1961). pulverized limonite or “brand” (tbra) from the stojančići locality (fig. 8) have also been studied in detail by jurković (1961) and therefore no new microscopic investigations of this sample have been made. common characteristics of the limestone sample (tvap1) are veins bearing brown siderite, pale yellow ankerite, and tiny white calcite veinlets (fig. 9). macroscopic and microscopic structural relationships suggest that the siderite was partly replaced by ankerite, whereas calcite represents the youngest occurrence (fig. 10). the limestone is dark gray micrite containing rare quartz grains, (up to 0.12 mm) and muscovite, (up to 0.06 mm). only vein and veinlet free parts of the limestone were taken for chemical analysis. the studied sample of carbonate shale (tvap2) is composed of clay-sized grains, and is a dark, fi ssile, and laminated rock (fig. 11). microscopic study revealed that it consists of clay minerals, detrital quartz, muscovite and variously sized spherical and oval-shaped calcispheres, which are characteristically 60 to 300 µm in diameter (fig. 12). the sample of white-gray coloured ankerite (tmix) shown in figure 13 consists of an intimately associated white area of coarse grained ankerite crystals, with regular grain boundaries and a gray area of fi ne to medium grained ankerite with black lobate grain boundaries, and interstitial places fi lled with a clayey-carbonaceous substance and quartz agfigure 7: photomicrograph of the internal radiating structure of goethite concretions (n) in compact limonite (sample tlim). figure 8: pulverized limonite or “brand” (sample tbra). figure 9: brown siderite and pale yellow ankerite veins and tiny white calcite veinlets that cut the studied limestone (sample tvap1) . figure 10: photomicrographs of siderite (sd), ankerite (ank) and calcite (cal) veins that cut limestone (sample tvap1). partial breakdown of siderite along cracks results in haematite occurrence (n+). figure 11: dark fi ssile laminate carbonate shale (sample tvap1). garašić and jurković: geochemical characteristics of diff erent iron ore types from the southern tomašica deposit, ljubija, nw bosnia geologia croatica 261 gregates (fig. 14). relics of fi ne grained ankerite with lobate black grain boundaries have been observed within the white coarse grained ankerite. ankerites of both, white and gray areas are characterized by undulose extinction. due to the intimate association of the white and gray areas of this sample, one chemical analysis of a mixed area was made. white coarse grained ankerite (sample tank), occurs in the form of an irregular nest (fig. 15) in the matrix of dark fi ne grained ankerite (sample tank 1). white coarse grained ankerite is characterized by regular grain boundaries and grains free of inclusions. in contrast, grain boundaries of dark fi ne grained ankerite are highly irregular, and the interstitial space is fi lled with a clayey-carbonaceous substance containing usually small quartz grains and rarely muscovite (fig. 16). dark fi ne ankerite grains show locally tiny quartz inclusions. the undulose extinction is typical for both coarse and fi ne grained ankerite. different parts of this non-homogeneous rock sample were carefully separated from each other for chemical analysis. white coarse grained ankerite (sample tanmic) also occurs in the form of an irregular nest, but this time in a matrix of reddish coarse grained siderite (sample tcor), which figure 12: photomicrograph of carbonate shale consisting of clay minerals, detrital quartz, muscovite and variously sized spherical and ovalshaped calcispheres (n+). figure 13: intimately associated white coarse grained area and gray fi ne to medium grained area of ankerite (sample tmix). figure 14: photomicrograph of the fi ne to medium part of an ankerite sample tmix with quartz aggregates fi lling interstitial places between ankerite grains having lobate grain boundaries (n+). figure 15: white coarse grained ankerite (sample tank) occurs in form of an irregular nest in the matrix of dark fi ne grained ankerite (sample tank1). figure 16: photomicrograph of the boundary area between coarse grained ankerite (sample tank) and fi ne grained ankerite (sample tank 1). grain boundaries of fi ne grained ankerite are highly irregular, the interstitial space is fi lled with a clayey-carbonaceous substance (n+). is surrounded by dark fi ne grained siderite (sample tmic) as shown in fig. 17. various parts of this non-homogeneous rock sample were carefully separated for chemical analysis. geologia croatica 65/2geologia croatica 262 interstitial spaces fi lled with a clayey-carbonaceous substance and disseminated quartz grains. partial breakdown of both types of siderite results in the occurrence of haematite along grain boundaries, cleavage and cracks in the siderite (fig. 18). ankerite and both type of siderite are characterized by undulose extinction. the sample of yellow coarse grained siderite (sample ad-2) irregularly embedded in a matrix of reddish fi ne grained siderite was collected in the adamuša opencast mine (fig. 19). again, fi ne grained mineral is characterized by irregular boundaries and interstitial spaces fi lled with a clayeycarbonaceous substance and disseminated quartz grains, whe reas the coarse grained mineral consists of polygonal grains. chemical analysis of yellow coarse grained siderite was undertaken, although due to the intimate association of yellow and reddish siderite it is possible that a minor quantity of reddish siderite was included in the analysis. careful examination of mineral thin-sections using trans mitted polarized light enabled separation of the fresh and weathered samples, and the different parts of non-homogeneous samples to be distinguished. selected samples were crushed, hand–picked under binocular microscope and powdered in an agate mortar for chemical analysis. major, minor and trace element contents were determined by inductively coupled plasma mass spectrometry (icp-ms) in the acme analytical laboratories (vancouver) ltd in canada. in the same laboratory the total organic carbon (tot/c) and total sulphure (tot/s) of all six samples were measured too. 4. analytical results 4.1. main oxides the concentrations of many main oxides (sio2, al2o3, tio2, na2o, k2o) in compact limonite are slightly higher but very similar to those in siderite, limestone and dark fi ne grained ankerite (table 1). slightly lower concentrations of these oxides, (but still similar to those in siderite and limestone) are displayed in the white coarse grained ankerite. pulverized limonite on the other hand differs signifi cantly, relative to compact limonite. the sio2 component in pulverized limonite is enriched by 3 times, al2o3 component by 10 times, na2o component by 7 times, k2o component by 4 times and the p2o5 component by 20 times compared to compact limonite (table 1). these elevated values are mostly comparable to carbonate shale which is even more enriched in the sio2 component (27.10 wt % compared to 16.73 wt % of pulverized limonite), but depleted in al2o3 (only 4.99 wt % in comparison with 11.78 wt% of pulverized limonite). there are positive correlations between the al2o3, k2o and tio2 contents and the aluminosilicate fraction of the samples. the fe2o3 and mgo contents in siderite vary from 3.09 and 5.11 wt%, to 51.66 and 58.34 wt% respectively. in ankerite, the fe2o3 content ranges from 13.94 to 21.35 wt%. its mgo content is between 9.29 and 10.41 wt%. mno values are positively correlated with fe2o3 in all samples. the highest mno content is present in siderite (2.15 to 2.55 wt%). ankerite figure 17: white coarse grained ankerite (sample tanmic) occurs in the form of an irregular nest in a matrix of reddish coarse grained siderite (sample tcor) which is surrounded by dark fi ne grained siderite (sample tmic). figure 18: photomicrograph of fi ne grained siderite (sample tmic) with ir regular grain boundaries and interstitial spaces fi lled with a clayey-carbonaceous substance and disseminated quartz grains. red haematite occurs along cracks and cleavage of siderite because of weathering processes (n). figure 19: yellow coarse grained siderite (sample ad-2) irregularly embedded in a matrix of reddish fi ne grained siderite from the adamuša opencast mine. white coarse grained ankerite and reddish coarse grained siderite are characterized by regular grain boundaries, whereas those of dark fi ne grained siderite are irregular with garašić and jurković: geochemical characteristics of diff erent iron ore types from the southern tomašica deposit, ljubija, nw bosnia geologia croatica 263 shows lower mno values (0.88 to1.10 wt%) and limestone has the lowest mno value (0.10 wt%). the highest cao content in siderite is found in the red coarse grained tcor sample (3.98 wt%) in the immediate vicinity of the ankerite nests. the cao content of the other two siderite samples varies from 1.34 to 1.63 wt%. ankerite is characterized by a cao content varying between 26.87 and 28.59 wt%. the greatest chemical differences between pulverized limonite and carbonate shale is visible in the content of fe2o3 (3.27 wt% in carbonate shale and 53.87 wt% in pulverized limonite) and cao (31.60 wt% in carbonate shale and 0.23 wt% in pulverized limonite). 4.2. ree content the ree content of ankerite, limestone, siderite and compact limonite is low (up to 22.49 ppm), in contrast to pulverized limonite (118.45 ppm) and carbonate shale (72.99 ppm), as reported in table 2. there is a clear positive correlation between the weight percent of the main oxides sio2 and al2o3 and ree (table 1, table 2) in compact limonite, pulverized limonite and carbonate shale. this suggests ree concentration dependence of the clay component in the samples. however, the same correlation is not so obvious for carbonates. the ree concentrations of all the studied samples are normalized to c1 chondrite (sun & mcdonough, 1989), in order to compare fractionations of light ree (la/sm)n, heavy ree (gd/yb)n, total ree (la/yb)n, eu anomaly (eu/ eu* = eun/√(smxgd)n and ce anomaly (ce/ce* = cen/(√la x pr)n) in different samples (table 2). the ree pattern of compact limonite is characterized by relatively low light ((la/sm)n = 2.87), heavy ((gd/yb)n = 0.98) and total ((la/yb)n = 3.19) ree fractionations, a strong positive eu anomaly (eu/eu* = 2.11) and weakly expressed negative ce anomaly (ce/ce* = 0.82) as shown in table 2 and fig. 20a. the total concentration of ree is 18.78 ppm. limestone exhibits slightly lower ree abundance (fig. 20b) and light ree fractionation (la/sm)n = 2.29), but more strongly expressed heavy ((gd/yb)n = 2.31) and total ((la/ yb)n = 5.08) ree fractionation compared to compact limonite. its eu anomaly (eu/eu* = 1.12) is positive, but very weak, whereas the ce anomaly (ce/ce* = 0.68) is negative and stronger than in compact limonite. the overall ree content is 9.15 ppm. studied coarse and fi ne siderite samples do not show differences in their ree patterns (fig. 20c). they all display signifi cant enrichment of lree over hree ((la/yb)n = 3.36–3.91, (la/sm)n = 1.29–1.97, (gd/yb)n = 1.18–2.21), a pronounced positive eu anomaly (eu/eu* = 2.24–3.40) and a small negative ce anomaly (ce/ce* = 0.78–0.87). their total ree concentrations vary from 13.71 to 13.23 ppm. in contrast to the ree patterns seen in siderite, those in ankerite show a clear distinction between fi ne grained and coarse grained samples (fig. 20d). the ree pattern of fi ne table 1: the main element content of the studied samples. sample mdl tlim tbra tvap1 tvap2 tmix tank tanmic tank 1 tcor tmic ad-2 mineral/ rock   compact limonite pulverized limonite limestone carbonate shale ankerite ankerite ankerite ankerite siderite siderite siderite white gray fi ne to coarse grained white coarse grained white coarse grained dark fi ne grained red coarse grained dark fi ne grained yellow coarse grained   wt.% wt.% wt.% wt.% wt.% wt.% wt.% wt.% wt.% wt.% wt.% wt.% sio2 0.01 4.98 16.73 3.51 27.1 2.23 0.31 0.10 4.96 3.64 3.36 1.77 al2o3 0.01 1.12 11.78 0.28 4.99 0.24 0.05 0.05 0.57 0.49 0.48 0.27 fe2o3 0.04 79.61 53.87 0.87 3.27 18.41 16.91 21.35 13.94 51.66 54.41 58.34 mgo 0.01 0.13 0.74 0.61 2.08 9.47 10.41 9.29 10.29 4.99 5.11 3.09 cao 0.01 0.15 0.23 52.24 31.6 27.18 28.59 26.87 28.47 3.98 1.63 1.34 na2o 0.01 0.03 0.15 0.03 0.12 0.05 0.05 0.04 0.04 0.04 0.03 0.04 k2o 0.01 0.29 1.38 0.08 1.36 0.06 0.01 0.01 0.16 0.13 0.14 0.07 tio2 0.01 0.05 0.47 <0.01 0.19 <0.01 <0.01 <0.01 0.02 0.01 0.02 0.01 p2o5 0.01 <0.01 0.22 0.02 0.06 <0.01 <0.01 <0.01 <0.01 0.03 0.02 <0.01 mno 0.01 0.84 0.82 0.10 0.28 1.01 0.97 1.10 0.88 2.19 2.15 2.55 cr2o3 0.002 <0.002 0.01 <0.002 0.007 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 loi –5.1 12.70 13.40 42.10 28.80 41.20 42.50 41.10 40.50 32.70 32.60 32.4 σ 0.01 99.90 99.80 99.84 99.86 99.85 99.80 99.91 99.83 99.86 99.95 99.88 tot/c 0.02 0.27 0.44 11.74 8.28 11.77 12.22 11.96 11.43 10.40 10.59 10.43 tot/s 0.02 <0.02 <0.02 <0.02 0.70 <0.02 <0.02 <0.02 0.03 <0.02 <0.02 0.03 geologia croatica 65/2geologia croatica 264 grained ankerite (sample tank1) is similar to the siderite patterns showing enrichment of lree over hree ((la/yb)n = 2.15), the positive eu anomaly (eu/eu* = 1.95) and the negative ce anomaly (ce/ce* = 0.78). differences exist in its lower (la/sm)n ratio (0.89) and greater (gd/yb)n ratio (2.46) compared with siderite. its σree is 11.49 ppm. in contrast, two coarse grained ankerite samples (samples tank and tanmic) exhibit remarkable depletion of lree over hree ((la/yb)n = 0.05–0.20), a strong reverse lree pattern ((la/sm)n = 0.04–0.10) and (gd/yb)n ratios ranging from 1.77 to 1.91. the coarse grained ankerite samples are like other studied samples characterized by positive eu anomaly (eu/eu* = 2.16–2.75) and negative ce anomaly (ce/ce* = 0.32–0.83) and their σree vary between 5.54 and 15.25. the tmix sample consisting of fi ne to coarse grained ankerite possesses the highest ree abundance (σree = 22.49 ppm) among the studied ankerite samples and has characteristics similar to those of fi ne grained ankerite (slight enrichment of lree over hree ((la/yb)n = 1.22), a positive eu anomaly (eu/eu* = 2.37), negative ce anomaly (ce/ce* = 0.87), low (la/sm)n ratio (0.47) and greater (gd/yb)n ratio (2.60)). in contrast to all other samples, pulverized limonite (fig. 20a) and carbonate shale (fig. 20b) show completely different ree patterns and abundances (up to 6 to 13 times higher relative to other samples) (fig. 20c,d). although pulverized limonite is characterized by the highest ree abundance (σree = 118.45) its ree fractionation patterns ((la/sm)n = 3.68, (gd/yb)n = 1.58, (la/yb)n = 9.41), a slightly positive eu anomaly (eu/eu* = 1.10) and small negative ce anomaly (ce/ce* = 0.81) are similar to those in the carbonate shale ((la/sm)n = 4.09, (gd/yb)n = 1.91, (la/yb)n = 10.63, (eu/eu* = 1.04, (ce/ce* = 0.89). 4.3. other trace elements the content of rb, cs, ba and ga are characterized by a positive correlation with k2o and al2o3 values, pointing to the aluminosilicate fraction of the samples. consequently, the pulverized limonite contains the highest values of rb (74.2 ppm), cs (14.8 ppm), ba (227 ppm) and ga (14.1 ppm). it is also characterized by the highest concentrations of v (104 ppm), zr (115.2 ppm) and y (19.3 ppm). table 2: rare earth element composition of the studied samples. sample mdl tlim tbra tvap1 tvap2 tmix tank tanmic tank 1 tcor tmic ad-2 mineral/ rock compact limonite pulverized limonite limestone carbonate shale ankerite ankerite ankerite ankerite siderite siderite siderite white gray fi ne to coarse grained white coarse grained white coarse grained dark fi ne grained red coarse grained dark fi ne grained yellow coarse grained   ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm la 0.10 3.60 27.3 1.70 16.30 1.40 <0.10 <0.10 1.20 2.20 2.60 1.80 ce 0.10 5.50 42.6 2.40 27.70 3.90 0.40 0.10 2.30 4.10 5.10 3.80 pr 0.02 0.75 6.16 0.44 3.55 0.86 0.14 0.06 0.44 0.75 0.86 0.63 nd 0.30 3.20 22.3 1.80 13.80 4.60 1.00 0.80 2.40 3.10 4.40 2.90 sm 0.05 0.81 4.79 0.48 2.57 1.91 0.62 1.57 0.87 0.72 0.95 0.90 eu 0.02 0.61 1.57 0.21 0.87 1.72 0.50 1.91 0.65 0.51 0.74 0.99 gd 0.05 0.96 3.97 0.67 2.54 2.58 0.81 2.87 1.19 0.67 0.85 0.88 tb 0.01 0.18 0.63 0.10 0.40 0.45 0.15 0.55 0.18 0.12 0.15 0.13 dy 0.05 1.06 3.64 0.58 2.14 2.31 0.77 3.09 1.01 0.75 0.97 0.67 ho 0.02 0.25 0.73 0.13 0.43 0.47 0.15 0.59 0.19 0.17 0.22 0.14 er 0.03 0.81 2.03 0.32 1.23 1.20 0.43 1.82 0.52 0.50 0.62 0.41 tm 0.01 0.13 0.34 0.05 0.19 0.16 0.07 0.26 0.08 0.09 0.10 0.07 yb 0.05 0.81 2.08 0.24 1.10 0.82 0.35 1.34 0.40 0.47 0.53 0.33 lu 0.01 0.11 0.31 0.03 0.17 0.11 0.05 0.19 0.06 0.08 0.08 0.06 σρεε   18.78 118.45 9.15 72.99 22.49 5.54 15.25 11.49 14.23 18.17 13.71 eu/eu* 2.11 1.10 1.13 1.04 2.37 2.16 2.75 1.95 2.24 2.52 3.40 ce/ce* 0.82 0.80 0.68 0.89 0.87 0.83 0.32 0.78 0.78 0.84 0.87 (la/yb)n 3.19 9.41 5.08 10.63 1.22 0.20 0.05 2.15 3.36 3.52 3.91 (la/sm)n 2.87 3.68 2.29 4.09 0.47 0.10 0.04 0.89 1.97 1.77 1.29 (gd/yb)n 0.98 1.58 2.31 1.91 2.60 1.91 1.77 2.46 1.18 1.33 2.21 garašić and jurković: geochemical characteristics of diff erent iron ore types from the southern tomašica deposit, ljubija, nw bosnia geologia croatica 265 figure 20: plot of rare-earth elements normalized to c1 chondrites (sun & mcdonough, 1989) in: a) compact and pulverized limonite; b) limestone and carbonate shale; c) siderite; d) ankerite. the sr content increases with the increasing calcium content of the samples due to the crystal chemical control. consequently the sr content increases from siderite (12.3 to 14.9 ppm), and ankerite (42.4 to 79.5 ppm) to being highest in the limestone (1051 ppm). the concentrations of co, ni, pb, zn and as, show a positive correlation with fe2o3 in siderite samples, whereas in the ankerite samples such correlation doesn’t exist. the content of co, ni and as in ankerite samples are positively correlated with al2o3 and sio2 components, whereas the pb, zn and cu contents are most likely linked to the presence of tiny sulphides near the grain boundaries. the highest values of ni (36.4 ppm), pb (116.6 ppm), zn (345 ppm), as (382.8 ppm) and cu (52.4 ppm) are found in pulverized limonite, whereas the carbonate shale is characterized by the highest content of co (25.9 ppm). the compact limonite contains elevated concentrations of many trace elements (cs, ga, hf, rb, th, v, zr,y, cu, zn, ni and sb) relative to siderite, ankerite and limestone (table 3). in the same comparison the highest contents of co (5.60 ppm) and as (4.60 ppm) are found in siderite, of hg (0.14 ppm) in ankerite and of u (1.60 ppm) and pb (11.1 ppm) in the limestone. in comparison with compact limonite, siderite, ankerite and limestone the concentrations of ni, co, cs, ga, hf, nb, rb, ta, th, u, v, w. zr, y, mo, cu, pb, zn, as, sb and hg are even more elevated in the pulverized limonite and carbonate shale (table 3). the only elements having higher concentrations in the carbonate shale than in pulverized limonite are co, bi, ag, hg and se (table 3). 5. discussion geochemical investigations of two limonite ore types show considerable differences in the content of their main elements, ree and other trace elements. in order to constrain their possible lithotype sources, the geochemical characteristics of studied siderite, ankerite, host limestone and carbonate shale are further discussed. 5.1. ree chemistry of carbonate phases generally, many factors may infl uence the ree content of carbonate minerals. the most important include the size of sites occupied by ree ions in the crystal lattice, ree chemistry of mineralizing fl uids and ree partitioning between the precipitating mineral and mineralizing fl uid (möller, 1983). in addition, according to möller et al. (2004), ree abundances are higher in hydrothermal than in cold fl uids and increase with decreasing ph (michard, 1989). in acid solutions lrees are enriched relative to hrees, geologia croatica 65/2geologia croatica 266 table 3: trace element content of the studied samples. sample mdl tlim tbra tvap1 tvap2 tmix tank tanmic tank 1 tcor tmic ad-2 mineral/ rock compact limonite pulverized limonite limestone carbonate shale ankerite ankerite ankerite ankerite siderite siderite siderite white gray fi ne to coa rse grai ned white coarse grained white coarse grained dark fi ne grained red coarse grained dark fi ne grained yellow coarse grained   ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm sc 1.0 2.0 12.0 <1.0 5.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 1.0 ba 1.0 201.0 227.0 26.0 140.0 24.0 5.0 8.0 18.0 17.0 21.0 44.0 be 1.0 1.0 2.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 co 0.2 2.7 18.1 0.2 25.9 2.7 0.5 0.8 4.1 3.6 5.6 11.7 cs 0.1 1.8 14.8 0.4 9.3 0.4 0.2 0.2 0.6 0.7 0.7 0.3 ga 0.5 3.2 14.1 0.5 7.4 0.6 0.5 0.5 1.0 2.7 3.1 3.9 hf 0.1 0.5 3.3 0.1 1.0 0.1 0.1 0.1 0.2 0.2 0.2 0.1 nb 0.1 1.0 10.2 0.3 4.1 0.2 0.1 0.1 0.5 0.3 0.3 0.4 rb 0.1 11.9 74.2 3.2 55.0 2.4 0.5 0.5 6.3 5.1 5.5 3.2 sn 1.0 <1.0 3.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 <1.0 sr 0.5 7.3 42.4 1051.1 357.3 55.1 79.5 42.4 66.5 14.4 12.3 14.9 ta 0.1 <0.1 0.8 0.1 0.3 0.1 0.1 0.1 0.1 0.1 0.1 <1.0 th 0.2 1.0 8.9 0.3 4.0 0.5 0.2 0.2 0.3 0.6 0.6 0.5 u 0.1 0.9 5.5 1.6 4.6 0.7 0.1 0.1 0.1 0.4 0.5 2.5 v 8.0 19.0 104.0 8.0 70.0 8.0 8.0 8.0 8.0 8.0 11.0 12.0 w 0.5 <0.5 1,5 0.5 1.2 0.5 0.5 0.5 0.5 0.5 0.5 <0.5 zr 0.1 20.0 115.2 2.3 31.9 1.6 1.0 0.4 5.9 5.3 6.6 4.4 y 0.1 7.7 19.3 4.8 14.0 15.3 5.5 17.8 7.8 5.0 5.8 4.8 mo 0.1 <0.1 2.5 0.1 9.9 0.1 0.2 0.1 0.8 0.2 0.3 0.5 cu 0.1 9.3 52.4 0.7 22.7 2.6 2.2 30.7 3.5 2.4 1.5 1.6 pb 0.1 3.4 116.6 11.1 54.3 1.7 1.8 1.8 5.0 1.3 1.5 136.7 zn 1.0 57.0 345.0 14.0 25.0 14.0 22.0 14.0 17.0 24.0 35.0 46.0 ni 0.1 10.7 36.4 1.2 35.6 4.3 1.1 1.6 6.3 5.4 7.2 11.6 as 0.5 1.2 382.8 0.5 34.8 4.3 0.5 0.5 6.7 3.6 4.6 5.5 cd 0.1 <0.1 0.2 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 <1.0 sb 0.1 0.8 3.5 0.3 4.5 0.2 0.1 0.1 1.2 0.1 0.2 0.6 bi 0.1 <0.1 0.3 0.1 0.9 0.1 0.1 0.1 0.2 0.1 0.1 <1.0 ag 0.1 <0.1 0.1 0.1 0.8 0.1 0.1 0.1 0.1 0.1 0.1 <1.0 au* (ppb) 0.5 <0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 1.5 0.5 <0.5 hg 0.01 0.04 0.52 0.05 0.7 0.05 0.13 0.01 0.14 0.03 0.03 0.09 tl 0.1 <0.1 0.3 0.1 0.2 0.1 0.1 0.1 0.1 0.1 0.1 <1.0 se 0.5 <0.5 0.5 0.5 1.9 0.5 0.6 0.5 0.5 0.5 0.5 <0.5 zr/tio2   0.040 0.025 >0.023 0.017 >0.016 >0.010 >0.004 0.030 0.053 0.033 0.044 zr/nb 20.000 11.290 7.670 7.780 8.000 10.000 4.000 11.800 17.670 22.00 11.000 nb/y 0.130 0.530 0.060 0.290 0.010 0.020 0.010 0.060 0.060 0.050 0.080 whereas al kaline solutions exhibit depletion of the lrees over hrees usually having la/lu < 1 (schwinn & markl, 2005). in the context of crystal chemistry, calcite should be characterized by enrichment of lree over hree in contrast to siderite that should display depletion of lree over hree. garašić and jurković: geochemical characteristics of diff erent iron ore types from the southern tomašica deposit, ljubija, nw bosnia geologia croatica 267 ankerite should show intermediate characteristics between these two patterns. the larger ca ion site in calcite incorporates larger lrees more easily, whereas the smaller fe ion site in siderite easily incorporates smaller hrees. thus the lree enrichment in siderite (fig. 20), and its overall greater ree content (σree = 13.71–18.17 ppm) in comparison with limestone (σree = 9.15 ppm), could not be solely attributed to crystallographic control, but indicates the precipitation of siderite from an lree enriched parent fl uid. strong depletion of lree over hree ((la/yb)n = 0.05–0.20) in the two white coarse grained ankerites on the other hand reveals that they were precipitated either from a colder and more alkaline mineralizing fl uid, or from a fl uid with a different source relative to siderite and fi ne grained ankerite. the negative ce anomaly, being the result of the oxidation of ce3+ to ce4+ and its consequent removal from the solution as ceo2, is typical for marine limestones (hu et al., 1988). the studied limestone exhibits a pronounced negative ce anomaly (0.68) and weak positive eu anomaly (1.13). the negative ce anomaly, although weaker, is present in siderite (0.78–0.87), fi ne grained ankerite (0.78), and also in one coarse grained ankerite (0.83). its lower values relative to limestone could be explained by lower ph or a lower po2 of mineralizing fl uids from which siderite and ankerite samples precipitated. the presence of a signifi cant negative ce anomaly (0.32) in the tanmic sample (coarse grained ankerite) indicates more oxygenated conditions for its precipitation. the additional noticeable feature in the studied carbonate ree patterns is a pronounced positive eu anomaly in siderite (2.24–3.40) and coarse grained ankerite (2.16–2.75). it is weaker in the fi ne grained ankerite (1.95) and weakest in the limestone (1.13). numerous analyses of ree concentrations in hydrothermal fl uids along oceanic ridges (michard & albarede, 1986; campbell et al., 1988) revealed that hydrothermal fl uids are enriched in σree (10– 104 times relative to seawater concentrations), and are characterized by a signifi cant positive eu anomaly (olivarez & owen, 1991). furthermore, textural evidence (the occurrence of veins and nests) in the studied siderite and ankerite samples from the olistostrome member in javorik formation support the hydrothermal origin. the interaction between some eu-rich mineralizing fl uid and limestone could be refl ected in the lree depletion of ankerite, due to effective hree complexion. additionally, the strong similarity in the content and the fractionation of hree in fi ne grained ankerite and limestone (fig. 20) might also indicate the possible involvement of limestone in the origin of ankerite. the analytical results obtained are in accordance with those published by strmić palinkaš et al. (2009) who suggested a hydrothermal-metasomatic origin of the fe mineralization. however, it should be emphasized that there was more than one hydrothermal stage. this is refl ected in ore texture (fi ne grained, coarse grained, veins, nests), colour (white, gray, red) and chemical features. signifi cantly lower al2o3 values occur in white coarse grained ankerite (0.05 wt.%) when compared to those in fi ne grained ankerite (0.57 wt%) and siderite (0.27–0.49 wt%). however, due to the lack of a clear positive correlation between wt% al2o3 and σree (see table 1 and 2) it seems that the rees are not hosted in detrital phases of carbonate samples. 5.2. ree chemistry of compact limonite the ree pattern of compact limonite ((la/sm)n = 2.87, (gd/yb)n = 0.98, (la/yb)n = 3.19, eu/eu* = 2.11, ce/ce* = 0.82) and its other trace element content (table 3), exhibits the closest genetic relationship with siderite. chemical wea thering of siderite most probably resulted in its extensive supergene modifi cation and the origin of compact limonite. textural relationships and fi eld occurrences of siderites and compact limonite support such a concept. it is also in accordance with the opinions of earlier investigators in this area (jurković, 1961; grubić & protić, 2003). the formation of limonite due to siderite weathering is observed and documented in many other geological environments (morris, 1980). 5.3. ree chemistry of carbonate shale and pulverized limonite considering the fractionation of light ree (la/sm)n, heavy ree (gd/yb)n and total ree (la/yb)n when normalized to chondrite (sun & mcdonough, 1989), the ree pattern of the studied carbonate shale is similar to those of the north american shale composite (nasc – gromet, 1984), and the post archean australian shale (paas – mclennan, 1989) as shown in fig. 21. the most remarkable difference is the absence of the pronounced negative eu anomaly in the carbonate shale, which is typical for nasc and paas. carbonate shale displays almost no eu anomaly (eu/eu* = 1.04) and has a small negative ce anomaly (ce/ce* = 0.89). an analogous ree pattern, but with enhanced overall ree content, is shown by pulverized limonite (eu/eu* = 1.10; (ce/ce* = 0.81). consequently, the carbonate shale might be one of the suitable lithotypes for providing the ree content to pulverized limonite. grubić & protić (2003) figure 21: plot of rare-earth elements normalized to c1 chondrites (sun & mcdonough, 1989) in compact and pulverized limonite compared with the ree pattern of north american shale composite (nasc – gromet, 1984) and post archean australian shale (paas – mclennan, 1989). geologia croatica 65/2geologia croatica 268 described comb-textured ankerite and dolomite limestone being completely enclosed by pulverized limonite. therefore they concluded that the weathering of ankerite led to the formation of pulverized limonite. the ree pattern of pulverized limonite analysed in this study differs strongly from the ree patterns of any ankerite types analysed here and hence would contradict such a conclusion. however, it has to be emphasized that the analysed sample of pulverized limonite (tbra) was not taken in its original place of formation, but in the pleistocene–quaternary lake limonite deposit (sto jan čići location). during transportation by rain, river or wind, pulverized limonite could become more or less contamina ted. the enhanced overall ree content in pulverized limo ni te (σree = 118.45 ppm) relative to compact limonite (18.78 ppm), may be explained by such crustal rock contamination. 5.4. other trace elements considerably higher concentrations of other trace elements in siderite samples (co = 3.6–11.7 ppm; ni =5.4–11.6 ppm; rb = 3.2–5.5 ppm; zr = 4.4–6.6 ppm), and fi ne grained ankerite (co = 4.1 ppm; ni = 6.3 ppm; rb = 6.3 ppm; zr = 5.9 ppm), relative to those in white coarse ankerite (co = 0.5–0.8 ppm; ni = 1.1–1.6 ppm; rb = 0.5 ppm; zr = 0.4–1.0 ppm), support the hypothesis of the precipitation of fi ne grained ankerite and white coarsed ankerite from different mineralizing fl uids. trace elements are in general depleted in compact limonite relative to pulverized limonite. the high values of zr (115.2 ppm) in pulverized limonite indicate the possible presence of a clastic component of igneous origin, whereas high values of rb (74.2 ppm), sr (42.4 ppm), th (8.9 ppm) indicate components derived by weathering from crustal felsic rocks. the enhanced concentrations of cu (52.4 pppm), pb (112 ppm), zn (345 ppm) and as (382.8 ppm) may be attributed to the presence of components arising from the weathering of sulphide minerals. the ratios of some immobile trace elements such as zr/tio2 and nb/y are regarded as very useful for protolith determination (winchester & floyd, 1977) because they don’t change during weathering processes. the values of the zr/tio2 ratio in compact limonite (0.040) and siderite (between 0.033 and 0.053), are in concordance with the postulated origin of compact limonite from siderite. in the fi ne grained ankerite (sample tank1), the zr/tio2 ratio is 0.030, whereas in the coarse grained ankerite it varies between 0.004 and 0.010. as pulverized limonite has a zr/tio2 ratio of 0.025, only fine grained ankerite or carbonate shale (0.017) might be regarded as its possible protolith. similar conclusions could be drawn on the basis of the zr/nb ratio which in siderite varies from 11 to 22 and in compact limonite is 20. in the pulverized limonite, the zr/nb ratio is 11.29, in carbonate shale 7.78, in the fi ne grained ankerite 11.8, and in the coarse grained ankerite it ranges between 4 and 10. however, the values of the nb/y ratios in pulverized limonite (0.53), carbonate shale (0.29), compact limonite (0.13), siderites (0.05–0.08), fi ne grained ankerite (0.06) and coarse grained ankerite (0.01–0.02) do not support the possibility of the origin of pulverized limonite through the weathering processes of ankerites. 5.5. field relationships and geochemical data the fi eld relationship between siderite and compact limonite, is consistent with the conclusion based on ree geochemistry, that compact limonite most probably originated by the alteration of siderite. compact limonite occurs as gossan formed in situ on siderite. pulverized limonite occurs in the fi eld as bedded and lensoid shape deposits in palaeolakes, but also enclosing ankerite relics and ankeritic limestone in the olistostrome member. the analyzed sample of pulverized limonite from a limonite deposit from the palaeolake exhibits signifi cantly distinct ree patterns relative to any ankerite types studied in this paper. carbonate shale is part of a fl ysch groundmass of the olistostrome member in which carbonate olistolith fragments, blocks and their mineralized parts are embedded. the remarkable resemblance of its ree pattern with that of pulverized limonite indicates the possibility that pulverized limonite may generally originate by the alteration of a carbonate shale or fl ysch groundmass. 6. conclusion two studied types of limonite ore from the southern to mašica mine display a notably distinct ree pattern, ree fractionations, eu anomalies and contents of other trace elements and main oxides. the compact limonite formed in situ on siderite is characterized by remarkable lower overall ree abundances, lower lree fractionation, lower and opposite hree fractionation, a more strongly expressed positive eu anomaly and far lower overall content of other trace elements compared to pulverized limonite. this supports the hypothesis of different protolith material for the two different limonite ore types. the ree pattern of compact limonite and siderite almost overlap, supporting the interpretation of former investigators (jurković, 1961; grubić & protić, 2003) who concluded that compact limonite originated by the alteration of siderite. the ree pattern of pulverized limonite on the other hand clearly differs from that of ankerite, which grubić & protić (2003) regarded as the protolith of pulverized limonite. on the basis of the similarity of their ree patterns, other trace element contents and zr/tio2 ratios, carbonate shale might be regarded as a potential protolith of pulverized limonite. alternatively, assuming that the analysed samples of pulverized limonite, collected in the pleistocene–quaternary lake limonite deposit, were contaminated during transportation by rain, river or wind, fi ne grained ankerite might also, on the basis of its zr/tio2 ratio and eu and ce anomaly, be a potential protolith of pulverized limonite. in order to develop full understanding of the formation of all limonite types in this area, the ree pattern and congarašić and jurković: geochemical characteristics of diff erent iron ore types from the southern tomašica deposit, ljubija, nw bosnia geologia croatica 269 tent of other trace elements in siderite occuring as lenses in the lowest parts of the geological column of southern tomašica, and in the superposed limonite (siderite-limonite member) and in pulverized limonite enclosing ankerite relicts (olistostrome member) remain to be investigated. acknowledgement we are gratefull to nenad raković and zorana grublje šić from ljubija iron ore mines who, thanks to their extensive fi eld experience and work over many years on iron deposits, helped with locating the most appropriate places for sampling. we also thank sabina strmić palinkaš and an anonymous reviewer for their fruitful critical reviews, which have helped improve this paper. references borojević šoštarić, s. (2004): geneza sideritno-baritno-polisulfi dnih rudnih ležišta u paleozoiku unutrašnjih dinarida [genesis of siderite-barite-polysulfi de ore deposit in paleozoic of inner dinarides – in croatian].– unpubl. master theses, university of zagreb, zagreb, 120 p. campbell, a.c., palmer, m.r., klinkhammer, g.p., bowers, t.s., edmond, j.m., lawrence, j.r., casey, j.f., thompson, g., humphris, s., rona, r & karson, j.a. (1988): chemistry of hot springs on the mid-atlantic ridge.– nature, 335, 514–519. cvijić, r. (1986): mineralni pigmenti ljubijske metalogenetske oblasti [mineral pigments of ljubija metallogenic province – in serbian].– xi kongres geologa jugoslavije, tara 1986, knjiga 4, 114–127. cvijić, r. (2001): mineralni resursi željeza, pelitoidne rude ljubijske metalogenetske oblasti i perspektive razvoja [iron ore resurses, pelitoid ores of the ljubija metallogenic province and perspective of the development – in serbian with english summary].– phd thesis, faculty of mining and geology, belgrade, 154 p. gradstein, f., ogg, j. & smith, a. (2006): a geologic time scale.– cambridge, university press, 589 p. gromet, l.p., dymek, r.f., haskin, l.a. & korotev, r.l. (1984): the “north american shale composite”: its compilation, major and trace element characteristics.– geochim. cosmochim. ac., 48, 2469–2482. grubić, a. & protić, lj. (2003): studija strukturnih i genetskih karakteristika tomašičkog rudnog polja [the study of structural and genetical characteristics of tomašica ore fi eld – in serbian].– in: grubić, a. & cvijić, r. (eds.): novi prilozi za geologiju i metalogeniju rudnika gvožđa “ljubija” [new contribution to the geology and metallogeny of the ljubija iron ore mine – in serbian]. institute of mining prijedor and mines of iron ore “ljubija” prijedor, prijedor, 63–134. grubić, a., protić, lj., filipović, i. & jovanović, d. (2000): new data on the paleozoic of the sana-una area.– in: proceedings of the international symposium geology and metallogeny of the dinarides and the vardar zone, anurs, banja luka, 49–54. hu, x., wang, y.l. & schmitt, r.a. (1988): geochemistry of sediments on the rio grande rise and the redox evolution of the south atlantic ocean.– geochim. cosmochim. ac., 52, 201–207. jurić, m. (1967): izvještaj o regionalnim istraživanjima paleozoika sane u 1966. godini [report about the regional studies of sana palaeozoic in year 1966 – in serbian].– geološki zavod u sarajevu. izveštaj u fondu stručnih dokumenata ržr ljubija, prijedor. jurić, m. (1969): rudna ležišta o naslagama omarsko–prijedorskog polja [ore deposits about the sequences of omarska-prijedor fi eld].– geol. glasnik, 13, 271–291, sarajevo. jurić, m. (1971): geologija područja sanskog paleozoika u sjeverozapadnoj bosni [geology of sana palaeozoic area in nw bosnia – in croatian].– geološki glasnik xi, sarajevo, 146 p. jurković, i. (1961): minerali željeznih rudnih ležišta ljubije kod prijedora [minerals of ljubija iron ore deposit near prijedor – in croatian with english summary].– geol. vjesnik, 14, 161–220. logomerac, v. (1960): priprema ljubijske sitnozrne rude “branda” za preradu u visokoj peći [preparation of the fi ne-grained ljubija ore “brand” for the processing in blast furnace].– elaborat, fond dokumenata “željezara sisak”, 97 p. mclennan, s.m. (1989): rare earth elements in sedimentary rocks: infl uence of provenance and sedimentary processes.– in: lipin, b.r. & mckay, g.a. (eds.): geochemistry and mineralogy of rare earth elements. reviews in mineralogy, 21, 169–200. michard, a. & albarede, f. (1986): the ree content of some hydrothermal fl uids.– chem. geol., 55, 51–60. michard, a. (1989): rare earth element systematics in hydrotehrmal fl uids.– geochim. cosmochim. ac., 53, 745–750. möller, p. (1983): lanthanoids as a geochemical probe and problems in lanthanoid geochemistry-distribution and behavior of lanthanoids in non-magmatic phases.– in: sinha, s.p. (ed.): systematics and the properties of the lanthanides, nato advanced studies institute series, series c, mathematics and physics sciences, 109, 561–616. möller, p., dulski, p., savascin, y., conrad, m. (2004): rare earth elements, yttrium and pb isotope ratios in thermal spring and well waters of west anatolia, turkey: a hydrochemical study of their origin.– chem. geol., 206, 97–118. morris, r.c. (1980): a textural and mineralogy study of the relationship of iron ore to banded-iron formations in the hamersley iron province of western australia.– econ. geol., 75, 184–209. olivarez, a.m. & owen, r.m. (1991): the europium anomaly of seawater: implications for fl uvial versus hydrothermal ree inputs to the oceans.– chem. geol., 92, 317–328. palinkaš, a.l. (1988): geokemijske karakteristike paleozojskih metalogenetskih područja: samoborska gora, gorski kotar, lika, kordun i banija [geochemical characteristics of paleozoic metallogenic regions: samoborska gora, gorski kotar, lika, kordun and banija – in croatian with english summary].– unpubl. phd theses, university of zagreb, 108 p. palinkaš, a.l. (1990): siderite-barite-polysulfi de and early continental rifting in dinarides.– geol. vjesnik, 43, 181–185. palinkaš, a.l., borojević, s., strmić, s., prochaska, w., spangenberg, j.e. (2003): siderite-hematite-barite-polysulfi de mineral deposits, related to the early intra-continental tethyan rifting, inner dinarides.– in: eliopoulos et al. (eds.): mineral exploration and sustainable development, millpress, rotterdam, 1221–1224. podubski, v. (1969): litostratigrafski razvitak paleozoika u sjeverozapadnoj bosni [lithostratigraphic development of palaeozoic in nw bosnia – in serbian].– geol. glasnik, 12, sarajevo, 165–195. schwin, g. & markl, g. (2005): ree systematics in hydrothermal fl uorite.– chem. geol., 216, 225–248. strmić palinkaš, s., spangenberg, j.e. & palinkaš, a.l. (2009): organic and inorganic geochemistry of ljubija siderite deposits, nw bosnia and herzegovina.– miner. deposita, 44/8, 893–913. sun, s.s. & mcdonough, w.f. (1989): chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes.– in: magmatism in the ocean basins, geological society, special publication, 42, 313–345. geologia croatica 65/2geologia croatica 270 šarac, m. (1981): metalogenetske karakteristike rudnosneoblasti ljubije [metallogenic chara-cteristics of the ljubija ore-bearing area – in serbian].– unpubl. phd theses, university of belgrade, 135 p. šarac, m. & vitaljić, b. (1973): omarska – povećani sirovinski potencijal, rudarsko–metalurškog kombinata “zenica” [omarska – increased raw material potential of the ore and metallurgical combine “zenica” – in serbian].– čelik, 45, zenica, 17–21. taylor, s.r. & mclennan, s.m. (1985): the continental crust: its composition and evolution.– blackwell, oxford, u.k., 312 p. winchester, j.a. & floyd, p.a. (1977): geochemical discrimination of different magma series and their differentiation products using immobile elements.– chem. geol., 20, 325–343. manuscript received december 30, 2010 revised manuscript accepted may 31, 2012 available online june 29, 2012 gc_2-2013_kb.indd geologia croaticageologia croatica geologia croatica 66/2 129–142 4 figs. 4 tabs. zagreb 2013 ab stra ct this paper presents the results of sampling surveys carried out in order to evaluate the environmental impact of the rude and the sv. jakob historical mining sites, nw croatia. the studied polymetallic ore deposits differ in their mineralogical and geochemical features as well as in the host rock lithology. the rude fe-cu-pb-zn-ba deposit is hosted by permian siliciclastic sediments. siderite, haematite, galena, sphalerite, chalcopyrite, pyrite, barite and gypsum are the major ore minerals. the sv. jakob pb-zn deposit occurs in the middle triassic dolostone. the most abundant ore minerals are galena, sphalerite and pyrite. although the deposits represent potential sources of numerous toxic metals, no pollution of the drainage streams and associated stream sediments was recorded. the studied mining sites are characterized by high carbonate/sulfi de ratios responsible for the alkaline character of the drainage streams (ph=7.3–8.7). consequently, the mining sites have very low potential for both generation of acid mine drainage and for leaching of heavy metals into the drainage systems. furthermore, the study revealed that the populated areas (stream waters with decreased redox potential, increased organic matter content, high no3 –, nh4 + and po4 3– concentrations; stream sediments enriched in exchangeable pb and zn) and the sava river alluvium (overfl owing streams enriched in hg) represent a greater environmental threat than the investigated polymetallic ore deposits. keywords: polymetallic ore deposits, exchangeable metals, stream water, stream sediments, samoborska gora mts., medvednica mts., nw croatia. environmental geochemistry of the polymetallic ore deposits: case studies from the rude and the sv. jakob historical mining sites, nw croatia  sabina strmić palinkaš1, dragana dogančić2, ladislav a. palinkaš1, jasmina obhođaš3, štefi ca kampić1, maja kuzmanović1 and maša martinić1 1 faculty of science, university of zagreb, horvatovac 95, hr-10000 zagreb, croatia; (sabina.strmic@inet.hr; phone: +385-1-4605-971; fax: +385-1-4605-998) 2 geotechnical faculty, university of zagreb, hallerova aleja 7, hr-42000 varaždin, croatia; (dragana.dogancic@gfv.hr; phone: +385-42-408-947) 3 department of experimental physics, ruđer bošković institute, bijenička c. 54, hr-10000 zagreb, croatia; (jasmina.obhodjas@irb.hr; phone: +385-1-4571-311) doi: 10.4154/gc.2013.10 1. introduction the polymetallic ore deposits represent the geochemical anomalies of numerous potentially toxic metals such as lead, copper, cadmium, mercury, arsenic and barium. although the primary minerals of these elements (mostly sulfi des) do not represent a signifi cant environmental threat, their weathering under surface conditions may mobilize heavy metals making them biologically available. the environmental behaviour of the polymetallic ore deposits varies according to the ore and gangue mineralogy, major and trace element geochemistry and the host rock lithology (e.g. mascaro et al., 2001; foley, 2002; huang et al., 2010; kirschbaum et al., 2012). the presented study focused on the two polymetallic ore deposits, at rude, in the samoborska gora mts., and sv. jakob, (medvednica mts.), in the vicinity of zagreb, nw croatia. the deposits differ in their mineralogical and geogeologia croatica 66/2geologia croatica 130 chemical features as well as in the host rock lithology. the rude fe-cu-pb-zn-ba deposit is hosted by permian siliciclastic sediments. siderite, haematite, galena, sphalerite, chalcopyrite, pyrite, barite and gypsum are the principal ore minerals (palinkaš et al., 2010). the sv. jakob pb-zn deposit occurs in the middle triassic dolostone. the most abundant ore minerals are galena, sphalerite and pyrite (šinkovec et al., 1988). both deposits are drained by surface streams which could transport potentially toxic metals downstream. the rude deposit is drained by the rudarska gradna creek. the geochemical and mineralogical study undertaken by čović (2003) to evaluate heavy metal levels in overbank sediments of the žumberak and samoborsko gorje mts., revealed an increased content of numerous metals (hg, cu, pb, ba, as, cr and fe) in samples from the rudarska gradna catchment. soils developed above the sv. jakob historic mining site were found to contain increased concentrations of pb, zn and cd, related to the oxidation of primary sulfi des in the near-surface weathering environment (durn et al., 1998). the deposit is located only 300 m north from the veliki potok creek headwater, and there is a strong possibility that the creek might transport signifi cant concentrations of heavy metals downstream. the primary objective of this study was to determine the environmental impact of the historical mining sites on the surrounding ecosystems, including the streams that drain them. stream water chemistry and stream sediment composition are discussed, as well as the geochemical behaviour of metals during the weathering processes in the two different types of polymetallic ore deposits. 2. geological setting the rude, samoborska gora mts., and the sv. jakob, medvednica mts., polymetallic ore deposits are located within the westernmost part of the zagorje mid-transdanubian zone (zmtz); pamić, & tomljenović, 1998; tomljenović, 2002). the samoborska gora and medvednica mts. consist of palaeozoic, mesozoic-palaeogene and neogene formations (fig. 1). the autochthon of samoborska gora mts. comprises: 1) palaeozoic unit, composed of late carboniferous dark gray schists, shales and sandstones. shallowing of the sedimentary basin evolved into a dry-land phase, followed figure 1: simplifi ed geological setting of the investigated areas with marked sampling sites along a) the rude ore deposit and marked sampling sites along the rudarska gradna creek (rg-1 – rg-12); b) the sv. jakob ore and marked sampling sites along the veliki potok creek (vp-1 – vp-12). strmić palinkaš et al.: environmental geochemistry of the polymetallic ore deposits: case studies... geologia croatica 131 by deposition of fi ne to coarse-grained sandstones, interlayered with conglomerates, dolostones and evaporites (herak, 1956). these deposits are unconformably overlain by an early triassic clastic-carbonate unit, followed by middle and late triassic carbonate-marl sediments, with occasional appearances of cherts, and 2) cretaceous mélange predominantly composed of basalts and diabases within shales, graywackes, conglomerates, radiolarites and limestones of dif ferent mesozoic ages, covered by neogene sediments. the volcanics, often as basalt-spilite pillow lavas, are probably products of a triassic rifting stage. the allochthon is represented by mesozoic carbonate platform lithotypes (šikić et al., 1979; tomljenović, 2000; palinkaš et al., 2010). tectonostratigraphic units of the medvednica mts. are grouped into four main units (fig. 1). autochthon: 1) tectonized ophiolite mélange, including all lithological members, from sediments, to mafi c and ultramafi c igneous components, 2) palaeozoic-triassic magmatic-sedimentary complex overprinted by early cretaceous metamorphism, 3) late cretaceous-paleocene flysch, and allochthon: 4) triassic and younger sequences belonging mainly to carbonate platform facies (šikić et al., 1978; šikić et al., 1979; šikić, 1995; palinkaš et al., 2010). 3. mineralization the rude fe-cu-pb-zn-ba deposit consists of two ore types, an epigenetic, hydrothermal vein-type beneath a stratiform, sedex type. epigenetic, epi-mesothermal, quartz-siderite veins with chalcopyrite, galena, sphalerite and barite, crosscut the middle-upper permian clastic rocks. the epigenetic part of the deposit represents a feeder zone of the sedex, stratiform ore lenses formed in an evaporitic pond-lagoon by sedimentation of gypsum-anhydrite, haematite, siderite and barite. laterally, epigenetic, epithermal barite-galena veins intersect upper permian coarse-grained sandstones. the deposit is covered by lower triassic variegated clastics (palinkaš et al., 2008; šinkovec, 1971). mining activities in the area began in the early 13th century with the exploitation of copper. the production of iron ore from siderite started in 1850 and lasted less than 10 years. according to palinkaš et al. (2010) the rude deposit is declared as a prototype of the permian siderite-polysulphide-barite deposits produced during the early stage of intracontinental rifting. the deposit is drained by the rudarska gradna creek (fig. 1), which originates approximately 1.8 km southwest of the deposit. generally, it runs southwest-northeastwards for about 16 km. in the upper part of the course, the creek fl ows through a rural area and it is fed by several small streams. after its confl uence with the lipovečka gradna creek, it fl ows through the town of samobor. the gradna creek joins the sava river in the vicinity of gradna village. after its headwater in the middle triassic carbonates, the rudarska gradna creek fl ows over the permian unmetamorphosed siliciclastic complex, the lower triassic clastic rocks, middle to upper triassic carbonates, cretaceous limestones, proluvial and alluvial sediments (fig. 1; šikić et al., 1978; šikić et al., 1979). the sv. jakob pb-zn deposit is hosted by non-metamorphosed middle triassic dolostone (palinkaš et al., 2008), with the ore occurring in the form of veinlets and lenses. galena is the principal ore mineral, and it is coarse grained. the vein-type mineralization, beside galena, comprises minor sphalerite, pyrite, quartz and calcite (šinkovec et al., 1988), and was actively mined during the 17th century. according to the epigenetic character of the ore mineralization, a simple ore paragenesis without copper minerals, and the fl uid inclusions and sulfur isotope data, the deposit is classifi ed as a mississippi valley type of pb-zn deposits formed during the stage of advanced intracontinental rifting in the middle triassic (palinkaš et al., 2008; šinkovec et al., 1988; durn et al., 1999; borojević šoštarić, 2004). the deposit is located at 830 m above sea level, approximately 300 m north of the veliki potok creek headwater. the veliki potok creek runs north-south for about 12 km, and is fed in its upper part by the mali potok creek and several small streams. the central and lower part of the creek fl ows through the urban area of zagreb. in the lowermost part of the course, about 500 m upstream from its entry point into the sava river; the veliki potok has its confl uence with the vrapčak creek (fig. 1). the veliki potok originates in the palaeozoic parametamorphic complex (fig. 1) composed of greywackes, siltstones, limestones, dolostones, muscovitechlorite and muscovite-quartz schists (šikić et al., 1978; šikić et al., 1979). according to several authors (đurđanović, 1973; belak et al., 1995) some protoliths from the parametamorphic complex are of triassic age. continuing downstream, the creek is entrenched in the cretaceous sedimentary rocks predominantly represented by fi ne-grained clastics. the orthometamorphic complex, predominantly composed of greenschist and metamorphosed gabbro and diabase, is referred to as being of devonian-carboniferous age. further, the creek fl ows through the neogene sediments represented mostly by sandstones, marls and limestones. the lowermost part of the creek dissects the sava river alluvial sediments (šikić et al., 1978; šikić et al., 1979). 4. samples and methods stream water and sediment samples were simultaneously collected from the rudarska gradna creek (n=12), the veliki potok creek (n=11) and the sava river (n=1) during the sampling campaign in october 2010. the sampling sites are shown on figure 1 and listed in table 1. collection and sample handling were conducted in accordance to the standard methodology for the analysis of the selected parameters. water samples were collected using two half-litre polyethylene (pet) bottles, one for the analysis of anions (so4 2–, po4 3–, cl–, no3 –) and ammonia, and other, which was pre-acid washed (10%, v/v, nitric acid 65%), for trace metal analysis. the bottles were rinsed three times with stream water prior to fi lling with the water sample. in the geologia croatica 66/2geologia croatica 132 laboratory, samples for trace metal analysis were fi ltered through 0.45 mm pore cellulose syringe fi lters, acidifi ed with hno3 to ph<2 and stored at 4°c. another bottle was frozen at –18°c for subsequent analyses of anions and ammonia. stream sediment samples were collected and stored in double polyethylene bags. at the laboratory, samples were air dried, disaggregated in an agate mortar, homogenized, and fi nally dry-sieved through stainless-steel screens to the fraction of <125 μm. water temperature, ph, redox potential, electrical conductivity and dissolved oxygen (do) measurements were conducted in situ on unfi ltered water using a portable hach lange hq40d multimeasure device. nitrate was electrochemically measured using a lowlevel calibrated nitrate-sensitive electrode (hach platinum series combination electrode, model 51920), connected to a volt meter (hach sension 2). to avoid the interference effects of bicarbonate ions, the ph of samples was adjusted to 3 by the addition of an acidic buffer (h2so4). ammonia content was determined using hach intellical™ isenh3181 gas-sensing ammonia ion selective electrode (ise) with a replaceable membrane module, refi llable outer body, double junction reference and built-in temperature sensor. the measuring range is in the interval between 0.007 mg/l and 14,000 mg/l nh3–n. the sample preparation procedure required the addition of an alkaline buffer (lioh) to ensure that the ammonia was essentially de-ionised prior to analysis. the chloride ion concentration was determined using a selective radiometer analytical chloride electrode ise25cl. sulphate was determined by a titrimetric method. a 0.1 ml volume of methyl orange was added to 100 ml of each water sample. the sample was titrated against 0.1 m hcl to a permanent orange colour. an additional 1 ml of 0.1 m hcl and 25 ml of bacl2 solution were then added. samples were heated to boiling and cooled in tap water. after 30 minutes, 25 ml volume of potassium chromate, 1 drop of aluminum chloride and 1.6 ml 0.1 m koh solutions were added. after 1 hour, any precipitate was removed by fi ltration and 100 ml of each fi ltrate was titrated against 10 ml 10% potassium iodide solution and sodium thiosulphate using starch indicator. total phosphates were analyzed by the ascorbic acid method (apha standard method 4500-p; apha, awwa, table 1: description and location of the sample sites. sample gauss-krüger coordinates lithology sample site description x y rg-1 5551315 5068279 middle triassic limestone the rudarska gradna headwater rg-2 5551349 5068151 middle triassic limestone the rudarska gradna creek, upstream from the rude deposit rg-3 5551311 5068284 middle triassic limestone the rudarska gradna creek, upstream from the rude deposit rg-4 5551315 5068279 middle triassic limestone the rudarska gradna creek, upstream from the rude deposit rg-5 5551823 5068293 permian unmetamorphosed siliciclastic rocks right confl uent of the rudarska gradna creek rg-6 5551820 5068295 permian unmetamorphosed siliciclastic rocks the rudarska gradna creek, upstream from the rude deposit rg-7 5552531 5069116 permian unmetamorphosed siliciclastic rocks right confl uent of the rudarska gradna creek, abandoned waste-rock dump rg-8 5553843 5070412 lower triassic clastic sediments the rudarska gradna creek, downstream from the rude deposit rg-9 5554470 5073216 upper triassic limestones the lipovečka gradna creek rg-10 5554409 5072907 upper triassic limestones the rudarska gradna creek, downstream from the rude deposit rg-11 5556019 5073652 proluvium the gradna creek, samobor center rg-12 5556384 5074588 proluvium the gradna creek vp-1 5572129 5082230 paleozoic/triassic(?) parametamorphic rocks the veliki potok creek vp-2 5572251 5081745 paleozoic/triassic(?) parametamorphic rocks the veliki potok creek vp-3 5572316 5081344 cretaceous clastic sediments the veliki potok creek vp-4 5572617 5080280 paleozoic/triassic(?) parametamorphic rocks the veliki potok creek vp-5 5572958 5079768 paleozoic orthometamorphic rocks the veliki potok creek vp-6 5573059 5079758 paleozoic orthometamorphic rocks the mali potok creek vp-7 5572994 5079604 paleozoic orthometamorphic rocks the veliki potok creek vp-8 5572763 5077404 pliocene clastic sediments the veliki potok creek, urban area vp-9 5572867 5076130 pliocene clastic sediments the veliki potok creek, urban area vp-10 5573103 5073379 alluvium the veliki potok creek, urban area vp-11 5573816 5071199 alluvium the veliki potok creek, urban area vp-12 5574057 5071255 alluvium the sava river strmić palinkaš et al.: environmental geochemistry of the polymetallic ore deposits: case studies... geologia croatica 133 efa, 1998). absorbance was measured at 880 nm using a hach dr4000 spectrophotometer. acidifi ed sample solutions were used for heavy metal concentration measurements, using the fl ame atomic absorption method for fe, mn, pb, cu, and zn and the graphite furnace technique for hg and cd measurements (perkin-elmer aanalyst 800). exchangeable metals were extracted from the stream sediments (m = 10 g) using 250 ml of 1 m nh4oac solution at ph =7.00. the sediment-solution slurry was shaken for 2 h, and the solution separated from the solid by fi ltration. the addition of nh4 + in excess to the soil displaces the rapid exchangeable alkali and alkaline cations from the exchange sites of the soil particles. the concentrations of metals in the solution were measured with a perkin-elmer aanalyst 800 atomic absorption spectrometer. bulk stream sediment composition was estimated using energy dispersive x-ray fl uorescence (edxrf). measurements were made with a w anode and mo secondary target in orthogonal geometry, with measurement parameters of 40 kv and 35 ma. the irradiation time was 1000 s. x-ray spectra were collected with a si(li) detector (fwhm=170 ev at 5.9 kev) and were analyzed using qxas program packagedirect comparison method. iaea “lake sediment” was used as a reference material. highly oriented samples of the <2 μm fraction of selected stream sediment samples were prepared for clay mineral identifi cation on air-dried, ethylene-glycol saturated, and heated (at 400 and 550 °c, respectively) samples according to the procedure described by starkey et al. (1984). instrumental conditions were 40 kv, 40 ma and constant time 5 s, with step scanning (0.02°2θ). 5. results the chemical characteristics of the water samples from the rudarska gradna and veliki potok creeks are listed in table 2. according to the croatian water quality guidelines (og 77/98), analyzed samples are classifi ed within classes i and ii, concerning the general physicochemical parameters (ph, conductivity and dissolved oxygen; fig. 2). according to nitrate and ammonium concentrations, the water samples belong to classes ii and iii and classes i and ii, respectively table 2: stream water analytical data for the rudarska gradna and veliki potok creeks. sample ph eh (mv) do (mg/l) conductivity (μs/cm) n-no3 – (mg/l) n-nh4 + (mg/l) cl– (mg/l) so4 2– (mg/l) p-po4 3– (mg/l) fe (mg/l) mn (mg/l) pb (mg/l) zn (mg/l) cu (mg/l) hg (μg/l) cd (μg/l) rg-1 7.39 306.7 9.75 520 1.10 0.05 1.74 3.1 <d.l. 0.012 <d.l. 0.045 0.006 <d.l. 0.043 <d.l. rg-2 8.45 257.8 10.77 527 1.41 0.04 1.91 4.4 <d.l. 0.016 <d.l. 0.038 0.013 <d.l. 0.040 <d.l. rg-3 8.47 258.6 10.29 506 1.65 0.04 3.44 4.4 0.005 0.037 <d.l. 0.039 0.030 <d.l. 0.049 <d.l. rg-4 8.52 239.4 10.10 538 1.94 0.07 13.96 4.2 0.013 0.259 0.004 0.031 0.014 <d.l. 0.043 <d.l. rg-5 8.12 202.4 10.18 518 1.67 0.12 11.62 6.6 0.021 0.183 <d.l. 0.022 0.028 <d.l. 0.041 <d.l. rg-6 8.45 225.9 10.36 605 2.26 0.08 16.14 5.3 0.023 0.163 0.006 0.015 0.006 0.002 0.056 <d.l. rg-7 8.34 252.0 10.58 666 1.77 0.03 12.54 8.1 <d.l. 1.107 0.119 0.012 0.040 0.009 0.099 <d.l. rg-8 8.43 222.3 10.20 631 3.02 0.20 16.68 7.6 0.021 0.166 <d.l. 0.038 0.029 0.004 0.033 <d.l. rg-9 8.62 232.5 10.94 512 2.26 0.05 9.38 3.2 0.008 0.101 <d.l. 0.071 0.033 0.005 0.037 <d.l. rg-10 8.44 212.0 10.51 627 2.31 0.14 14.36 6.1 0.023 0.428 <d.l. 0.065 0.015 0.009 0.178 <d.l. rg-11 8.68 229.5 10.84 547 2.35 0.04 10.90 4.5 0.044 0.130 <d.l. 0.087 0.009 0.003 0.078 <d.l. rg-12 8.69 223.9 10.70 545 2.25 0.04 11.84 4.7 0.016 0.110 <d.l. 0.076 0.010 <d.l. 0.747 0.092 vp-1 7.60 200.1 11.14 427 2.03 0.03 23.80 5.8 0.005 0.173 <d.l. 0.049 0.009 0.008 0.375 <d.l. vp-2 7.33 201.1 11.20 418 1.82 0.04 22.30 3.8 0.010 0.822 0.071 0.046 0.025 0.009 0.335 <d.l. vp-3 8.00 201.5 11.90 422 1.64 0.08 22.00 4.7 0.007 0.905 0.096 0.054 0.035 0.008 0.025 <d.l. vp-4 7.79 201.6 11.68 387 1.71 0.03 15.00 4.4 0.002 0.209 <d.l. 0.027 0.020 0.008 0.005 <d.l. vp-5 8.23 194.8 11.91 381 1.77 0.04 14.00 4.5 0.006 0.619 0.011 0.055 0.022 0.007 0.043 <d.l. vp-6 8.03 196.4 11.81 350 1.27 0.03 12.80 4.9 0.005 0.220 <d.l. 0.050 0.018 0.007 0.081 <d.l. vp-7 7.96 179.8 11.87 376 1.70 0.05 13.88 4.9 0.004 0.121 <d.l. 0.049 0.028 0.009 0.058 <d.l. vp-8 7.87 178.9 11.29 551 3.35 0.23 17.78 4.2 0.013 0.267 <d.l. 0.074 0.022 0.010 0.078 <d.l. vp-9 8.41 168.9 11.75 552 3.41 0.18 18.28 5.0 0.031 0.213 <d.l. 0.028 0.021 0.010 0.806 <d.l. vp-10 8.45 166.3 11.37 563 3.78 0.25 18.75 5.8 0.021 0.509 <d.l. 0.072 0.034 0.010 1.282 <d.l. vp-11 8.38 168.6 11.64 535 3.18 0.20 11.14 5.7 0.013 0.882 0.003 0.053 0.029 0.012 0.864 <d.l. vp-12 8.02 170.9 10.92 420 2.35 0.12 5.55 4.5 0.007 0.159 <d.l. 0.046 0.071 0.010 0.848 <d.l. <d.l. – below detection limit geologia croatica 66/2geologia croatica 134 (fig. 3). increased concentrations of various forms of nitrogen in rural and urban areas indicate the infl uence of domestic wastewaters, mostly attributed to the discharge of sewage into the creeks or to the drainage from septic tanks. the results for total phosphorus classify all samples within class i (fig. 2). measured concentrations of sulfates and chlorides were considerably lower than the maximum allowable concentrations (mac) allowed by the croatian regulations for drinking waters (og 47/08). iron and manganese concentrations in water samples mostly exceed the mac for drinking waters (fig. 4). elevated lead content classifi es the analysed samples within classes iv and v. lead had its highest water content in urban areas (sampling sites rg-11 and vp-10; fig. 4) refl ecting an anthropogenic origin. according to their mercury concentrations, the water samples mostly belong to class iv (fig. 4). the copper level varies from class i to class iii. low concentrations of zinc and cadmium are within the ranges proposed for class i. a summary of the nh4oac extracted contents of fe, mn, pb, zn, cu, hg and cd in stream sediments is given in table 3 and figure 4. iron contents vary from 0.550–2.075 figure 2: the physico-chemical parameters of a) the rudarska gradna creek, b) the veliki potok creek. strmić palinkaš et al.: environmental geochemistry of the polymetallic ore deposits: case studies... geologia croatica 135 mg/kg, mn content from 13.550–107.775 mg/kg, pb up to 4.275 mg/kg, zn up to 3.425 mg/kg, cu from 0.275–8.575 mg/kg, and cd from 6.625–98.250 mg/kg. mercury is mostly below the detection limit. the exceptions are samples vp-3 and vp-10 with hg concentrations of 0.900 and 1.650 mg/ kg, respectively. the bulk chemical composition of the stream sediments is summarized in table 4. mean k content for the sediments on metamorphic and siliciclastic terrains is comparatively higher than for the sediments on carbonate terrain, refl ecting the lithological contribution of this element. the principal carriers of k are k-feldspars, biotite, micas and clay minerals. as expected, the highest ca values are recorded for the stream sediments collected on carbonate terrains. the fe concentrations are mostly lower than the average shale value (table 4). sampling site rg-7 near the abandoned wasterock dump of the rude deposit is the exception. the mean concentrations of pb, zn, cu and as are signifi cantly higher than the average shale concentrations. according to the xrd patterns, kaolinite and illite represent the most abundant clay minerals in all the analyzed stream sediments. figure 3: variations in nitrate, ammonia and phosphate content along a) the rudarska gradna creek, b) the veliki potok creek. geologia croatica 66/2geologia croatica 136 strmić palinkaš et al.: environmental geochemistry of the polymetallic ore deposits: case studies... geologia croatica 137 6. statistical treatment the statistical analyses that applied univariate (basic statistic parameters) and bivariate analysis (correlation matrix) were performed on the analytical results obtained from 24 sampling sites. for each sampling site, 42 descriptors consisting of 5 lithological and 37 geochemical variables were observed and included in the statistical treatment. lithological variables were defi ned as a percentage of selected lithological units at the sampling site (e.g. rose et al., 1970; peh, 1992; halamić et al., 2001). as the bedrock lithologies of the medvednica and samoborska gora mts. comprise a variety of igneous, sedimentary and metamorphic rocks of different stratigraphic and tectonic settings, a simplifi ed representation of lithology with as little as possible loss of useful information was necessary (halamić et al., 2001). for this purpose lithological data were generalized from the geological map of croatia (scale 1:100.000), zagreb sheet (šikić et al., 1978). the study areas comprise only fi ve lithological units which were broadly related to the corresponding stratigraphic nomenclature (table 1). these units were further utilised as lithological variables which were specifi ed as follows: lit1 – triassic carbonate rocks; lit2 – permian unmetamorphosed complex, triassic, cretaceous and pliocene clastic sediments; lit3 – prolluvium and alluvium; lit4 – parametamorphites; and lit5 – orthometamorphites. additionally, the settlement infl uence variable was estimated for all sampling sites. an environmental impact of the settlements is pronounced in both urban and rural areas with no sewage and sewerage facilities. 7. discussion the primary ore mineralization usually is not stable under surface conditions (low temperature and pressure, high activities of water, oxygen and co2). weathering products could be summarized within 3 principal groups: 1) residual figure 4: variations in dissolved, exchangeable and total metals content along the rudarska gradna and veliki potok creeks. a) iron, rudarska gradna; b) iron, veliki potok; c) manganese, rudarska gradna; d) manganese, veliki potok; e) lead, rudarska gradna; f ) lead, veliki potok; g) zinc, rudarska gradna; h) zinc, veliki potok; i) mercury, rudarska gradna; i) mercury, veliki potok. geologia croatica 66/2geologia croatica 138 primary minerals, resistant to chemical and physical weathering; 2) secondary minerals, including clay minerals, hydrous fe-al-oxides, sulfates and carbonates; and 3) soluble (mobile) products. the mobility of metals depends mostly on ph and the redox potential of the solution as well as on the possibility for the formation of complexes. metals may be adsorbed onto feand mn-hydroxides (hem, 1977; tessier et al., 1985; feng et al., 2007), clay minerals (rybicka et al., 1985), organic matter (davis, 1982; özkaraova gungor et al., 2010) and amorphous silica (james & macnaughton, 1977). co-precipitation with ferric and/or manganese oxyhydroxide can also decrease heavy metal content in the stream waters. the rude deposit represents a potential source of lead (galena), zinc (sphalerite), iron (siderite, chalcopyrite, haematite), as well as sulfate (gypsum, anhydrite and oxidized sulfi de species). the ore mineralization of the sv. jakob deposit is simple and comprises only galena, sphalerite and pyrite. numerous geochemical surveys revealed an increased content of heavy metals in the topsoils of urban and pristine areas of the zagreb region (namjesnik-dejanović, 1994; romić & romić, 2003; sollitto et al., 2010) as well as in the overbank sediments of the sava river (čović, 2003; pavlović et al., 2004). as both deposits are drained by the surface streams there is the possibility that they also contribute to the pollution. according to the principal geochemical features, the rudarska gradna creek is divided into 3 segments: 1) the headwater, 2) the segment upstream from the rude mining site, and 3) the segment downstream from the rude mining site. although the rudarska gradna creek rises within the middle triassic carbonate rocks, the headwater is characterized by a slightly decreased ph value (rg-1; fig. 2), refl ecting the strong infl uence of the underlying siliciclastic sediments, mostly cretaceous shales, sandstones and cherts (fig. 1). an increased eh value suggests low organic matter content. the no3 –, nh4 + and po4 3– concentrations, as well as the content of all analyzed metals, with exception of lead, are very low (fig. 4). an increased pb concentration is attributed to the remobilization of lead from the middle triassic sediments under moderately low ph. the segment between the headwater and the rude mining site displays a uniform ph value (ph≈8.5) despite the presence of several small tributary streams with low alkalinity (e.g. rg-5; ph=8.12). the progressive decrease in redox potential coincides with the increase in nitrate, ammonia and phosphate concentrations, suggesting a common source of organic matter, nitrogen and phosphorous. the stream water shows a gradual decrease in lead content mainly due to its alkaline character causing the precipitation and/or adsorption of lead to the stream sediments. the sediment analyses revealed an increase in the exchangeable and total lead content downstream (fig. 4) indicating that both processes, adsorption and precipitation, should be considered. water at the abandoned waste-rock dump of the rude ore deposit is characterized by a slight decrease in ph and an increase in the eh value. nitrates, ammonia and phosphates are signifi cantly lower than in the main stream, indicating the diminished infl uence of anthropogenic pollution. increased concentrations of metals in the water are expected due to the weathering of ore minerals. the weathering of sulfi de-bearing parageneses usually results in a large decrease in ph value. in the case of the rude deposit, the observed decrease is minor, indicating that weathering of siderite reduces the acidifi cation effect. namely, according to reactions (1) and (2), weathering of siderite produces a neutral to slightly acid solution as indicated in the reactions below (skousen et al., 1997): feco3 + 0.25 o2 + 2.5 h2o → fe(oh)3 + h2co3 (1) and h2co3 ↔ h2o + co2 (2). consequently, the weathering of fe-minerals under oxidizing conditions results in the precipitation of fe-hydroxide which represents the predominant phase in the bulk sediment composition (fig. 4). the decreased content of all exchangeable metals (fig. 4) suggests ph as a key parameter controlling metal mobility. under decreased ph, the competition between h+ and the dissolved metals for ligands is more signifi cant. it decreases the adsorption abilities of metals, and consequently increases their mobility. sometimes, with only a drop in a few ph units, the fi xation percentage of metals on sediment particles may range from almost 100% to 0% (gundersen & steinnes, 2003; peng et al., 2009). table 3: exchangeable metals content in the stream sediments from the rudarska gradna and veliki potok creeks. sample fe (mg/kg) mn (mg/kg) pb (mg/kg) zn (mg/kg) cu (mg/kg) hg (mg/kg) cd (μg/kg) rg-3 1.000 32.400 1.200 0.925 0.675 <d.l. 38.725 rg-4 0.825 52.650 1.600 <d.l. 0.600 <d.l. 50.250 rg-6 0.875 107.775 2.500 1.300 0.875 <d.l. 98.250 rg-7 0.550 13.550 1.775 0.600 1.300 <d.l. 60.425 rg-8 0.900 55.675 1.775 1.150 4.250 <d.l. 83.875 rg-9 1.400 36.375 1.775 1.825 0.625 <d.l. 51.525 rg-10 1.300 92.375 4.275 1.575 8.575 <d.l. 76.325 rg-11 1.775 72.775 3.250 2.500 2.300 <d.l. 63.850 vp-1 1.075 73.150 0.775 <d.l. 0.475 <d.l. 11.125 vp-2 0.875 83.475 0.750 0.525 0.400 <d.l. 38.575 vp-3 1.000 101.250 <d.l. <d.l. 0.275 0.900 25.325 vp-4 1.400 49.575 <d.l. <d.l. 0.475 <d.l. 15.450 vp-5 2.075 85.125 0.525 <d.l. 0.650 <d.l. 10.950 vp-6 1.775 62.350 0.700 <d.l. 0.600 1.650 28.575 vp-7 1.450 53.575 0.625 <d.l. 0.425 <d.l. 26.775 vp-8 1.875 40.425 1.525 0.925 0.625 <d.l. 22.925 vp-9 1.775 69.400 1.550 2.125 0.700 <d.l. 57.475 vp-10 1.975 62.300 1.700 3.425 0.950 <d.l. 6.625 vp-12 1.900 14.825 1.700 1.000 0.500 <d.l. 40.225 <d.l. – below detection limit strmić palinkaš et al.: environmental geochemistry of the polymetallic ore deposits: case studies... geologia croatica 139 the segment downstream from the rude mining site displays a decrease in redox potential and an increase in nitrogen and phosphorous species, suggesting the enhanced infl uence of urbanization on the water quality. the concentrations of iron, manganese and zinc in the water gradually decrease downstream, suggesting the diminishing infl uence of the ore deposit (fig. 3). the increase in copper concentration is attributed to agricultural activities and the usage of cuso4-based fungicides in the vineyards (halamić et al., 2003). the stream sediments, characterized by the progressive increase in the exchangeable and total metal contents downstream (fe, mn, pb, zn, cu), indicate that the mobility of metals is controlled by adsorption and precipitation. according to the geochemical features, the veliki potok creek is divided into 2 segments: 1) the upper course fl ows through an uninhabited area and 2) the lower course fl ows through the urban area. the upper segment of the creek is characterized by moderate ph and high redox potential. an increased eh value suggests low organic matter content. the no3 –, nh4 + and po4 3– concentrations, as well as the content of all analyzed metals, with the exception of manganese, are very low (fig. 3; fig. 4). an increased mn concentration might be attributed to the remobilization of manganese from the middle triassic sediments. the low heavy metal content in the upper course, as well as a low sulfate concentration, indicates that the sv. jakob pb-zn-ag deposit does not represent a potential pollution source for the draining streams. the lower part of the creek is characterized by an increased ph value especially in the segment which fl ows over alluvial sediment (vp-10 to vp-12). increased conductivity of the stream water within the populated area generally points to a higher content of total dissolved solids. the progressive decrease in redox potential coincides with the increase in nitrate, ammonia and phosphate concentrations, suggesting a common source of organic matter, nitrogen and phosphorous, mostly from domestic wastewaters in the urban areas without sewerage facilities. agricultural activity in the suburbs, including the use of synthetic and organic fertilizers, may also increase the nitrate, ammonia and phosphate contents of the stream waters. the stream sediments display a progressive increase in the exchangeable and total metals contents (fig. 4). statistical analyses applied to the results obtained from both of the study areas allow additional data interpretation. a positive correlation between the measured ph values of the stream water and the presence of triassic carbonates (variable lit1; r=0.53) is expected due to the high buffering capacity of carbonate rocks. whereas the content of several exchangeable metals positively correlates with the ph value (rpb=0.55, rzn=0.52, rcd=0.51), so ph should be considered to be an important factor in the control of metal mobility. the redox potential (eh) correlates positively with the variable lit1 (r=0.59) and negatively with variable lit3 (r=–0.48). electrical conductivity of water, the measure for the concentration of total dissolved solids, increases in the siliciclastic terrains (lit2; r=0.54) and decreases in the orthometamorphites (lit5; r=–0.58). conductivity is also increased in the urban/rural areas (r=0.56). table 4: bulk chemical composition of the stream sediments from the rudarska gradna and veliki potok creeks. sample k (%) ca (%) fe (%) mn (ppm) ti (ppm)/ cr (ppm) ni (ppm) pb (ppm) zn (ppm) cu (ppm) as (ppm) rb (ppm) sr (ppm) y (ppm) zr (ppm) rg-3 1,23 5,60 1,53 547 2365 53 70 23 80 46 10 59 88 43 332 rg-4 2,26 0,97 4,10 1742 4107 113 116 35 100 57 19 123 111 73 312 rg-6 2,39 1,52 3,76 1618 4129 60 79 73 152 61 29 117 137 74 318 rg-7 2,90 0,74 4,32 1394 5075 41 52 103 154 111 51 141 153 89 465 rg-8 2,28 2,72 3,49 1903 3766 61 51 219 153 139 81 99 170 68 389 rg-9 1,43 6,69 1,36 358 2743 44 45 43 88 32 17 53 113 44 315 rg-10 1,67 4,01 2,47 813 3568 29 33 372 104 171 130 79 153 64 447 vp-1 2,98 1,07 4,17 921 5726 87 76 28 110 33 20 129 120 90 423 vp-2 3,19 0,33 4,16 890 6565 103 68 33 111 39 19 142 115 95 424 vp-3 2,98 1,00 3,81 772 5275 52 56 35 79 39 20 140 129 87 368 vp-4 2,77 1,13 4,11 1065 4949 61 71 30 112 41 22 127 147 85 402 vp-5 2,47 1,32 3,99 930 5364 81 61 35 112 45 21 115 159 89 5035 vp-6 3,25 0,40 5,53 1554 5657 117 92 34 140 56 25 148 156 85 345 vp-7 2,34 0,97 4,85 1085 6164 79 58 23 117 39 17 108 145 82 405 vp-8 2,39 3,39 3,29 690 4243 59 49 29 110 33 17 107 197 71 370 vp-9 2,03 3,76 2,56 598 4306 42 42 25 103 31 14 87 169 70 403 vp-10 2,22 2,56 3,06 569 4937 50 56 31 133 40 15 105 168 75 447 vp-11 1,78 4,84 2,06 586 2948 45 42 157 98 96 56 70 131 49 315 vp-12 1,75 7,15 1,95 451 1872 46 44 39 119 26 15 72 220 46 206 geologia croatica 66/2geologia croatica 140 generally, the concentration of metals in water does not show correlation with the lithological variables. the exceptions are mercury and zinc which correlate positively with alluvial/proluviall sediments (lit3; rhg=0.82, rzn=0.66). the increased hg concentrations in the sava river alluvium were attributed to the urbanization, industrial and mining activities upstream (namjesnik-dejanović, 1994; pa linkaš et al., 1996; halamić et al., 2003; pavlović et al., 2004). exchangeable zinc also correlates with lit3 (r=0.52). the bulk metal concentrations display a strong lithological infl uence. triassic carbonates (lit1) correlate positively with the total ca content (r=0.46) and negatively with k, rb, fe, zn, ti, v and y concentrations. alluvial/proluviall sediments (lit3) show a positive correlation with ca (r=0.39) and sr (r=0.53). parametamorphitic rocks (lit4) correlate with total k (r=0.48), and orthometamorphites (lit5) display correlations with the group of immobile elements, such as fe (r=0.54), cr (r=0.48), zr (r=0.54), and ti (r=0.44). whereas both of the investigated ore deposits were situated in the vicinity of the settlements, it was important to determine the infl uence of the urban/rural areas on the quality of stream water and sediments. increased conductivity of stream waters within populated areas (r=0.56) generally indicates a higher content of total dissolved solids. the populated areas correlate well with the concentrations of nitrate (r=0.91), ammonia (r=0.86) and phosphate (r=0.64) indicating their common source, mostly from domestic wastewaters in the urban and rural areas without sewerage facilities. in the rural area, agricultural activities, including the use of synthetic and organic fertilizers, may also increase the nitrate, ammonia and phosphate contents in the stream waters. furthermore, the urban/rural areas statistically correlate with the concentration of mercury in stream waters (r=0.60) and with the content of exchangeable lead (r=0.49) and zinc (r=0.82) from the stream sediments. for the appropriate interpretation of the heavy metals origin, it is important to keep in mind that the populated areas are mostly located on the alluvial deposits (lit3; r=0.43). as mentioned above, the hg content in stream waters positively correlates with lit3 and the urban/rural areas. furthermore, it displays a negative correlation with the eh value (r=–0.61) indicating the increased hg mobility in a reducing, organic rich, environment, probably as a consequence of the hg complexation with organic ligands. among the organic ligands, humic substances are the most important compounds naturally occurring in soils, sediments and waters (thurman, 1986; gungor, & bekbolet, 2010). as humic and fl uvic acids are soluble in dilute alkali solutions, and the ph of all water samples collected over lit3 is above 8, these types of organic molecules could signifi cantly contribute to the mobilization of mercury from the alluvial sediments. the concentration of copper in the water samples also correlates negatively with measured eh values (r=–0.75) pointing to the importance of organic complexes in copper mobilization. according to wu et al., (2002) humate and fl uvate complexes mobilize cu (ii) ions at ph greater than 8. negative correlation (r=–0.42) between lead in water and the measured redox potential suggests that formation of the pb-organic complexes might also mobilize lead. 8. conclusion although the rude and the sv. jakob polymetallic ore deposits represent potential sources of numerous heavy metals, pollution of water and stream sediments downstream from the deposits was not recorded. buffering reactions with the carbonate country rocks (dolostone, limestone), as well as with carbonate ore and gangue minerals (siderite, calcite), are responsible for the alkaline character of the drainage streams. consequently, the deposits are not considerably weathered and the mobility of metals is signifi cantly reduc ed. the present study revealed that the populated areas represent a greater environmental threat than the investigated polymetallic ore deposits. stream waters in the populated areas, especially in the urban and rural areas without sewerage facilities, are characterized by a decreased redox potential (attributed to the high organic matter content), increased conductivity and increased concentrations of nitrate, ammonia and phosphate. stream sediments in the urban/rural areas have high contents of exchangeable lead and zinc. the sava river alluvium, characterized by its high mercury content, represents an additional environmental threat. the accumulation of hg within the alluvial deposits is attributed to the urbanization, industrial and mining activities upstream. the overlapping of the populated areas (decreased redox potential, high organic matter content) and the hg enriched alluvium resulted in the increased hg mobility probably due to the complexation of mercury with the organic ligands. acknowledgement this study was supported by the ministry of science, education and sports of the republic of croatia, through project no. 119-09827091175. the authors are grateful to sibila borojević šoštarić and an anonymous referee for critical reviews and helpful suggestions which improved the content and presentation of the manuscript. references apha, awwa, efa (1998): standard methods for the examination of water and wastewater, 20th ed., washington, dc, usa. belak, m., pamić, j., kolar-jurkovšek, t., peckay, z. & karan, d. (1995): alpinski regionalnometamorfni kompleks medvednice (sjeverozapadna hrvatska) [alpine regional metamorphic complex of the medvednica mt., nw croatia – in croatian].– 1. hrvatski geol. kongres, zbornik radova, 1, 67–70, zagreb. borojević šoštarić, s. (2004): geneza sideritno-baritno-polisulfi dnih ležišta u paleozoiku unutrašnjih dinarida [genesis of siderite-barite-polysulphide ore deposits within palaeozoic of internal dinarides – in croatian].– unpubl. masters thesis, university of zagreb, 120 p. čović, m. (2003): geokemijske i mineraloške karakteristike poplavnih sedimenata žumberka i samoborskog gorja [geochemical and mineralogical signatures of overbank sediments, žumberak and samostrmić palinkaš et al.: environmental geochemistry of the polymetallic ore deposits: case studies... geologia croatica 141 borsko gorje, croatia. – in croatian].– unpubl. master thesis, faculty of mining, geology and petroleum engineering, zagreb, 139 p. davis, j.a. (1982): adsorption of natural dissolved organic matter at the oxide/water interface.– geochim. cosmochim. acta, 46, 2381–2393. đurđanović, ž. (1973): o paleozoiku i trijasu medvednice (zagrebaèke gore) i područja dvora na uni na temelju konodonta [about the palaeozoic and the triassic of medvednica mt. and the area near dvor na uni on the basis of conodonts – in croatian].– geol. vjesnik, zagreb, 25, 29–49. durn, g., miko, s., čović, m., barudžija, u., tadej, n., namjesnik-dejanović, k. & palinkaš, l. (1999): distribution and behaviour of selected elements in soil developed over a historical pb–ag mining site at sv. jakob, croatia.– j. geochem. explor., 67, 361–376. feng, x.h., zhai, l.m., tan, w.f., liu, f. & he, j.z. (2007): adsorption and redox reactions of heavy metals on synthesized mn oxide minerals.– environ. pollut., 147, 366–373. foley, n.k. (2002): environmental geochemistry of platform carbonate-hosted sulphide deposits. http://pubs.usgs.gov/of/2002/of02195/che.txt. gundersen, p. & steinnes, e. (2003): infl uence of ph and toc concentration on cu, zn, cd, and al speciation in rivers.– water res., 37, 307–318. gungor, e.b.o. & bekbolet, m. (2010): zinc release by humic and fulvic acid as infl uenced by ph, complexation and doc sorption.– geoderma, 159, 131–138. halamić, j., peh, z., bukovec, d., miko, s. & galović, l. (2001): a factor model of the relationship between stream sediment geochemistry and adjacent drainage basin lithology, medvednica mt., croatia.– geol. croat., 54, 37–51. halamić, j., galović, l. & šparica, m. (2003): heavy metal (as, cd, cu, hg, pb and zn) distribution in topsoil developed on alluvial sediments of the drava and sava rivers in nw croatia.– geol. croat., 56, 215–232. hem, j.d. (1977.): reactions of metal-ions at surfaces of hydrous ironoxide.– geochim. cosmochim. acta, 41, 527–538. herak, m. (1956): geologija samoborskog gorja.– acta geol., jazu, zagreb, i, 49–74. huang, x., sillanpää, m., gjessing, e.t., peräniemi, s. & vogt, r.d. (2010): environmental impact of mining activities on the surface water quality in tibet: gyama valley.– sci total environ., 408, 4177–4184. james, r.o. & macnaughton, m.g. (1977): the adsorption of aqueous heavy metals on inorganic minerals.– geochim. cosmochim. acta, 41, 1549–1555. kirschbaum, a., murray, j., lópez, e., equiza, a., arnosio, m. & boaventura, g. (2012): the environmental impact of aguilar mine on the heavy metal concentrations of the yacoraite river, jujuy province, nw argentina.– environ. earth sci., 65, 493–504. mascaro, i., benvenuti, m., corsini, f., costagliola, p., lattanzi, p. parrini, p. & tanelli, g. (2001): mine wastes at the polymetallic deposit of fenice capanne (southern tuscany, italy): mineralogy, geochemistry and environmental impact.– environ. geol., 41, 417–429. namjesnik-dejanović, k. (1994): distribucija teških metala u tlima grada zagreba i njegove okolice [distribution of heavy metals in the soils of zagreb and its surrounding areas – in croatian].– unpubl. master thesis, university of zagreb, 208 p. og 77/98: water classifi cation act. narodne novine (2008): uredba o klasifi kaciji voda. no 77. og 47/08: regulation on health safety of drinking water. narodne novine (2008): pravilnik o zdravstvenoj ispravnosti vode za piće. no 47. özkaraova gungor, e.b. & bekbolet, m. (2010) zinc release by humic and fulvic acid as infl uenced by ph, complexation and doc sorption.– geoderma, 159, 131–138. palinkaš, l., namjesnik-dejanović, k., miko, s., durn, g. & pirc, s. (1996): distribution of mercury, lead and cadmium in zagreb city soils.– in: richardson, m. (ed.): environmental xenobiotics, taylor & francis, london, 355–374. palinkaš, l., borojević šoštarić, s. & strmić palinkaš, s. (2008): metallogeny of the northwestern and central dinarides and southern tisia.– ore geol. rev., 34, 501 520. palinkaš, l., borojević šoštarić, s., strmić palinkaš, s., prochaska, w., spangenberg, j., cuna, s. & šinkovec, b. (2010): permian-polysulphide-siderite-barite-haematite deposit rude in samoborska gora mts., zagorje-mid-transdanubian zone of the internal dinarides.– geol. croat., 63, 93–115. pamić, j. & tomljenović, b. (1998): basic geological data from the croatian part of the zagorje-mid-transdanubian zone.– acta geol. hungarica, 41, 389–400. pavlović, g., prohić, e. & tibljaš, d. (2004): statistical assessment of geochemical pattern in overbank sediments of the river sava, croatia.– environ. geol., 46, 132–143. peh, z. (1992): factor model of the geomorphological system of a part of northwestern croatia.– geol. croat., 45, 163– 172. peng, j.-f., song, y.-h., yuan, p., cui, x.-y. & qiu, g.-l. (2009): the remediation of heavy metals contaminated sediment.– j. hazard. mater., 161, 633–640. rose, a.w., dahlberg, e.c. & keith, m.l. (1970): a multiple regression technique for adjusting background values in stream sediment geochemistry.– econ. geol., 65, 156–165. rybicka, e.h., calmano, w. & breeger, a. (1985): heavy metals sorption/desorption on competing clay minerals; an experimental study.– appl. clay sci., 9, 369–381. šikić, k. (1995): geološki vodič medvednice.– zagreb: inst. geol. istraž., zagreb, 199 p. šikić, k., basch, o. & šimunić, a. (1978): osnovna geološka karta sfrj 1:100 000. list zagreb, l33–80 [basic geological map of sfry 1:100000, zagreb sheet – in croatian].– inst. geol. istraž., zagreb (1972), sav. geol. zavod, beograd. šikić, k., basch, o. & šimunić, a. (1979): tumač osnovne geološke karte 1:100000, list zagreb.– sav. geol. zavod, beograd, 81 p. šinkovec, b. (1971): geologija ležišta željezne i bakrene rude u rudama kraj samobora [geology of iron and copper ore from rude near samobor – in croatian].– geol. vjesn., zagreb, 24, 165–181. šinkovec, b., palinkaš, l. & durn, g. (1988): ore occurrences on mt. medvednica (in croatian with english summary).– geol. vjesn., zagreb, 41, 395–405. skousen, j., renton, j., brown, h., evans, p., leavitt, b., brady, k., cohen, l. & ziemkiewicz, p. (1997): neutralization potential of overburden samples containing siderite.– j. environ. qual., 26, 673–681. starkey, h.c., blackmon, p.d. & hauff, p.l. (1984): the routine mineralogical analysis of clay-bearing samples.– u.s.g.s. bull., 1563, 1–32. tessier, a., rapin, f. & carignan, r. (1985): trace metals in oxic lake sediments: possible adsorption onto iron oxyhydroxides.– geochim. cosmochim. acta, 49, 183–194. thurman, e.m. (1986): organic geochemistry of natural waters.– martinus nijhoff/dr w. junk publishers, boston, 497 p. geologia croatica 66/2geologia croatica 142 tomljenović, b. (2000): zagorje-mid-transdanubian zone.– in: pamić, j. & tomljenović, b. (eds.): vijesti.– fieldtrip guidebook. proc. of the pancardi 2000, dubrovnik, croatia, 1–3 october, 2000, zagreb, 37/2, 27–33. tomljenović, b. (2002): strukturne karakteristike medvednice i samoborskog gorja [structural characteristics of the mts. medvednica and the samoborsko gorje mts. – in croatian].– unpubl. phd thesis, university of zagreb, 208 p. wu, j., west, l.j. & stewart, d.i. (2002): effect of humic substances on cu(ii) solubility in kaolin-sand soil.– j. hazard. mater., 94, 223–238. manuscript received august 07, 2012 revised manuscript accepted april 30, 2013 available online june 19, 2013 in memo jurak.indd 273 in memoriam professor vladimir jurak (1942–2010) � doi: 104154/gc.2011.23 geologia croatica 64/3 273–277 zagreb 2011 geologia croaticageologia croatica professor vladimir jurak died after serious illness on march 4th, 2010. he was born in zagreb on august 4th, 1942, where he fi nished elementary and high-school. after that he started to study geology at the faculty of mining, geology and petroleum engineering, university of zagreb. he graduated in 1967 and fi nished his phd thesis in 1983 at the university of beograd. professor vladimir jurak started to work as assistant in 1967 after graduation in the department of basic and applied geology at the faculty of mining, geology and petroleum engineering in zagreb. he was elected assistant professor in 1985, associate professor in 1992, professor and fi nally professor in permanent position. he was the head of the department of engineering geology, hydrogeology and geology of oil and coal (1991−1995). at the beginning of his work at the faculty of mining, geology and petroleum engineering he was the assistant on hydrogeological and engineering geology courses and the professor on the courses of engineering geology at undergraduate and post-graduate level. he was the founder and fi rst lecturer of several new courses in the fi eld of engineering geology at graduate, post-graduate and doctoral levels, where he combined his broad theoretical knowledge with great professional experience. for several years, he was the head of post graduate study in engineering geology. he also participated in lecturing at the faculty of civil engineering for several years as well as at the faculty of geotechnics in varaždin. his approach to lectures was very professional. each year he updated his lectures with new knowledge from the literature and with concrete examples from professional practice. vladimir jurak was an advisor for more than twenty bsc, 3 msc, and 7 phd theses, as well as a member of the evaluating committees for more than ten msc and phd exams. as the head, he took great care over the students’ papers in order that they were more complete and substantial. – he was a member of the presidency of the committee for engineering geology and hydrogeology and a member of the board for landslide in that committee in the former yugoslavia. – he was secretary of the croatian geological society (1971−1972). – he was a member of the editorial board of ‘geologia croatica’ (1991−1996) throughout his active life, he participated in numerous investigations and projects with the engineers and workers of the civil engineering institute (igh), geophysical department andrija mohorovičić, faculty of geodesy and faculty of agriculture in zagreb. geologia croatica 64/3geologia croatica 274 organized by the society of civil engineering engineers and the society for rock mechanics croatia, with the aim of explaining to the civil engineers, the importance of geology in solving engineering problems during designing and building. he held public lectures in the frame of the croatian geological society and scientifi c stand of the civil engineering institute. he took part in numerous scientifi c and professional meetings: over thirty national ones and over fi fty international ones. at these meetings, he was often the co-organizer of the professional excursions and one of the co-authors of geological guides and he also participated in plenary and invited lectures. for many years he was the scientifi c co-operator of the croatian geological survey, as a member of reviewcommissions for the basic engineering geological map of the republic of croatia as well as in complex studies and scientifi c-professional designs. from 2001 he was the coordinator of the scientifi c – professional design council for leading and realization of the „project of the complex geotechnical and seismic investigations for the needs of planning and building in the area of the town of zagreb”. he was also a reviewer for particular scientifi c projects fi nanced by the ministry for science, education and sports. unfortunately he died on march 4th, 2010, and although it was known that he was seriously ill, it was still very painful news. there is no doubt that professor jurak was one of the leading experts in the fi eld of engineering geology. we will remember him as a man who always tried to connect the engineering experience and science. he gladly presented his great knowledge and experience to younger colleagues. we will defi nitely remember professor jurak as a great friend and a great man who passionately loved his profession, his colleagues, his country, and his family. let him rest in peace! čedomir benac, snježana mihalić and tomo novosel bibliography: bubnov, s., cvijanović, d., jurak, v., magdalenić, a., skoko, d. & vukovojac, d. (1971): seismic zoning of zagreb.– in: 3rd european symposium on earthquake engineering, proceedings, sofi a, 1970. bulgarian academy of sciences press, 95–102. bubnov, s., cvijanović, d., jurak, v., magdalenić, a. & skoko, d. (1971): preliminarna karta seizmičke mikrorajonizacije grada zagreba.− in: 1. jugoslavenski simpozij o hidrogeologiji i inženjerskoj geologiji, zbornik radova 2, herceg-novi, 1971. jugoslavenski komitet za hidrogeologiju i inženjersku geologiju, 67–73. baturić, j. magdalenić, a., gregl, t. & jurak, v. (1972): djelomična potvrda herzbergovog zakona u primorskom kršu.− in: 2. jugoslavenski simpozij o hidrogeologiji i inženjerskoj geologiji, zbornik radova, sarajevo, 1972. jugoslavenski komitet za hidrogeologiju i inženjersku geologiju, 9–15. professor vladimir jurak was also very active in practical work, in addition to his lecturing duties. for ten years he was engaged in hydrogeological investigations in the karst terrains as co-operator with professor antun magdalenić. later, he devoted himself to work in the area of engineering geology where he became one of the leaders in the development of this branch of geology in the republic of croatia. while teaching engineering geology, he introduced modern rock mass classifi cations (bieniawski, burton) as well as the application of geological strength index (gsi) and hoek-brown’s criterion for rock fracture. he always pointed out that engineering geology could be applied and used only as a part of an interdisciplinary approach in the framework of geotechnical investigations. credit is due to him for teaching students the application of engineering geophysics (seismic, geo-radar and geoelectric measurements) in the frame of geotechnical investigations. he often used geophysics in his investigations and especially for evaluating the thickness of the different rock mass weathering belts, erosion properties of rock and in evaluation under the seismic conditions. he studied a fascinating, broad range of problems in the area of engineering geology, but was also concerned with several characteristic ones. from a weathering aspect, he was interested in the different contactolite rocks (skarns, kornfels, orthoamphibolites) on papuk mountain. he was the coauthor of the engineering geological study (1:10 000) for the design of the fi rst motorway in croatia (zagreb – rijeka). he participated in geotechnical investigations of the bridge site over the river rijeka dubrovačka. he studied clastic rock sediments in the macelj sandstone complex for the design of micro accumulations. he participated in investigations for the design of remedial work on the revitalization of the old medvedgrad ruins. based on their content, his studies can be placed into several groups: seismic and geotechnical zonation, mass movements and soil erosion. he willingly participated as the consultant on engineering geological problems during the design and building of numerous objects. in the last decade of his work he worked on the microzonation of slopes of the sljeme – medvednica mountain in zagreb. he also intensively investigated the erosion in the fl ysch areas of istria and kvarner as well as the instabilities of slopes at the contacts of carbonate and fl ysch rock complex in the same area. he specially focused his work on the area of extensive erosion in vinodol valley. he always intended to collect as much data as possible that could be used in lectures. he was tireless in that, and did not consider geology as a profession, as it was his passion. therefore, he often investigated the area he visited during his summer holidays, together with his wife željka. almost during his whole working period professor jurak actively participated, with great enthusiasm, in domestic scientifi c projects. he was the leader of three scientifi c projects and at the same time co-worker on several other projects. several times he was the lecturer at professional seminars on rock mechanics and soil mechanics which were čedomir benac, snježana mihalić & tomo novosel: in memoriam professor vladimir jurak (1942–2010) geologia croatica 275 savjetovanje: jedinstvena geotehnička istraživanja urbanih cjelina u svrhu geotehničke i seizmičke mikrorajonizacije, zbornik radova 1, zadar, 1983, 313–325. tonejec, m., megla, t., jurak, v. & kanajet, b. (1984): prijedlog uputa za registriranje i istraživanja nestabilnih padina i klizišta sfrj.− in: 8. jugoslavenski simpozij o hidrogeologiji i inženjerskoj geologiji, zbornik referata 2, budva, 1984, 227–251. magdalenić, a., jurak, v. & bonacci, o. (1985): analysis of a karst spring (yugoslavia).– karst water resources: ankaraantalya symposium, proceedings, ankara-antalya 1985. iahs publishers, p. 161. jašarević, i., jurak, v., cvijanović, d., kvasnička, p., matasović, n. & mitrović, g. (1986): mogućnost geo tehničkog modeliranja fl išnih padina u okolici dubrovnika za potrebe seizmičke i geotehničke mikrorajonizacije.− in: 4. kongres saveza društava za seizmičko građevinarstvo jugoslavije, zbornik radova, cavtat,, 1986, 89–100. jašarević, i. & jurak, v. (1987): stability of the fl ysch coastal slopes of the adriatic sea in the static and seismic conditions.– in: herget, g. & vongpaisal, s. (eds.): 6th international congress on rock mechanics, proceedings 1, montreal, 1987. taylor & francis, 411–418. jurak, v., matasović, n., cvijanović, d., jašarević, i., garašić, m. & slovenec, d. (1987): defi niranje prirodnih uvjeta terena na području župe dubrovačke za potrebe geotehničkoseizmičkog mikrozoniranja.− in: 9. jugoslavenski simpozij o hidrogeologiji i inženjerskoj geologiji, zbornik referata, 2, priština, 1987. savez inženjera i tehničara rudarske, geološke i metalurške struke jugoslavije, 41–60. magdalenić, a., bonacci, o. & jurak, v. (1987): sliv izvora bulaž u središnjoj istri.− krš jugoslavije, 12/1, 1−26. jurak, v., novosel, t., mitrović, g. & krsnik, m. (1989): ocjena kvalitete stijenske mase za potrebe temeljenja mosta preko rijeke dubrovačke.− in: 7. jugoslavenskog simpozija za mehaniku stijena i podzemne radove, zbornik radova. društvo za mehaniku stena i podzemne radove srbije u suradnji sa savezom društava inženjera i tehničara beograda, 33−38. szavits-nossan, a., jurak, v., cvijanović, d., matasović, n., grubić, n. & aničić, d. (1990): odnos između geotehničkih značajki terena i oštećenja zgrada izazvanih kninskim potresom 1986. godine.− in: 5. kongres sdsgj, zbornik radova, bled, 1990, 73−81. magdalenić, a., jurak, v. & benac, č. (1992): inže njer skogeološka problematika izgradnje luke u jugoistočnom dijelu bakarskog zaljeva.− pomorski zbornik, 30, 633−654. jurak, v., vrkljan, i. & drmić, z. (1994): mehanička svojstva intaktne stijene i stijenske mase karbonatnog masiva montovjerne (gruž).− in: mavar, r. (ed.): savjetovanje geotehnika prometnih građevina, saopćenja 1, novigrad, 1994. institut građevinarstva hrvatske, građevinski fakultet sveučilišta u zagrebu, 169−179. jurak, v. & mihalić, s. (1995): zoniranje područja zagreba na osnovne geotehničke sredine.− in: mavar, r. (ed.): 2. geotehnički problemi u urbanim sredinama, savjetovanje hdmtt, priopćenja, 1, varaždin, 1995. hrvatsko društvo za mehaniku tla i temeljenje, 429−439. jurak, v., kovačić, d. & garašić, m. (1995): procjena seizmičke stabilnosti nekih blokovskih paleoklizišta.− in: vlahović, i., velić, i. & šparica, m. (ed.): 1. hrvatski geološki kongres, zbornik radova, opatija, 1995. institut za geološka istraživanja, hrvatsko geološko društvo, 269−274. jurak, v., kovačić, d. & garašić, m. (1995): seismic stability of paleoslides on the south adriatic coast.– in: the interplay between geotechnical engineering and engineering geology. 1th european conference on soil mechanics and foundation engineering, proceedings 4, copenhagen, 1995. danish geotechnical society, 77–82. jurak, v. & novosel, t. (1972): inženjerskogeološke prilike na dijelovima trase ceste karlovac-rijeka (dionica kupjak-grobnik).− ceste i mostovi, xviii, 4, 100–105. hernitz, z. & jurak, v. (1973): primjena paleostrukturne i statističke analize naslaga mlađega tercijara u području ivanić-grada (sjeverna hrvatska).− nafta, 7–8/1973, 24, 343−367. jurak, v. (1973): seizmička mikrorajonizacija “pilot-kasete” u priobalnoj zoni skadarskog jezera (crna gora).− geološki vjesnik, 25, 293−298. jurak, v. & magdalenić, a. (1974): ispitivanje homogenosti pregradnog profi la brane s obzirom na vodopropusnost metodama neparametarskog testiranja.− geološki vjesnik 27, 299−308. magdalenić, a. & jurak, v. (1974): hidrogeološke prilike pregradnog mjesta he salakovac na neretvi.− in: 3. jugoslavenski simpozij o hidrogeologiji i inženjerskoj geologiji, zbornik radova, opatija, 1974. jugoslavenski komitet za hidrogeologiju, inženjersku geologiju i geofi ziku, 177–186. magdalenić, a., šikić, d. & jurak, v. (1974): problematika vodoopskrbe opatijske rivijere.− in: iii. simpozij dinarske asocijacije, ii, zagreb, 1974. novosel, t., jurak, v. & orešković, m. (1975): procjena koefi cijenta seizmičnosti (ks) na mikrolokaciji mjerenjem seizmičkih karakteristika tla pomoću “terra scouta”.− in: 13. savjetovanje jugo slavenskog društva za mehaniku tla i fundiranje, saopćenja 1, budva, 1975, 99–111. jurak, v. & magdalenić, a. (1976): inženjerskogeološke informacije iz lugeon-ovog postupka u karbonatnim stijenama (na primjeru pregradnog mjesta he salakovac na neretvi).− građevinar, xxviii, 3, 70−79. magdalenić, a. & jurak, v. (1976): mogućnost zahvata podzemnih i površinskih voda u okolici lovrana (istra).− in: 8. jugoslavenski geološki kongres, zbornik radova 4, ljubljana, 1976. 95– 110. magdalenić, a., jurak, v., kovačević, s. & capar, a. (1976): problem zahvata podzemne vode u dolini sunje.− in: 4. jugoslavenski simpozij o hidrogeologiji i inženjerskoj geologiji, zbornik radova, skopje, 1976. 223–234. magdalenić, a., raljević, b. & jurak, v. (1976): inže njerskogeološke i hidrogeološke osnove za potrebe konsolidacijskih radova.− in: 1. jugoslavenski simpozij za konsolidaciju tla, zbornik referata, zagreb, 1976, 57–63. jurak, v. (1983): značajke otjecanja u obraslom kršu (na primjeru porječja donje mrežnice u usporedbi s glinom).− in: jugoslavenski simpozij o inženjerskoj hidrologiji, zbornik radova i, split, 1983. građevinski institut – zagreb i jugoslavensko društvo za hidrologiju. jurak, v. (1984): hidrogeološka interpretacija krškog porječja kao putokaz za speleološka istraživanja.− in: 9. jugoslavenski speleološki kongres, zbornik predavanja, karlovac, 1984, 237–249. jašarević, i., matasović, n., bradvica, i., jurak, v., grubić, n., cvijanović, d., vulić, ž. & šaban, b. (1978): the approach to geotechnical-seismic microzonation on the example of the dubrovnik region.– in: hajdin, n. & dobričanin m. (eds): international conference on design, construction and repair of building structures in earthquake zones. proceedings, dubrovnik, 1987. jinpros, business association of yugoslav producers of precast components and industrialized constructions, 309–318. jurak, v., kanajet, b. & golijanin, g. (1982): fotogrametrijsko dokazivanje erozije u neogenskim naslagama sinjskog polja.− in: 7. jugoslavenski simpozij o hidrogeologiji i inženjerskoj geologiji, zbornik referata 2, novi sad, 1982, 205–212. ortolan, ž., novosel, t., pollak, z. višić, i., jurak, v., andrić, m. & sviben, d. (1983): seizmička i geotehnička mikrorajonizacija područja “m” iz okolice dubrovnika.− in: geologia croatica 64/3geologia croatica 276 marić, b., dujmić, d. & jurak, v. (1995): određivanje uvjeta rekonstrukcije nekih elemenata medvedgrada.− in: mavar, r. (ed.): geotehnički problemi u urbanim sredinama, 2. savjetovanje hdmtt, priopćenja, 1, varaždin, 1995. hrvatsko društvo za mehaniku tla i temeljenje, 351−358. matković, i., jurak, v. & miklin, ž. (1995): sustavna evidencija nestabilnih padina i klizišta na području grada zagreba.− in: mavar, r. (ed.): geotehnički problemi u urbanim sredinama, 2. savjetovanje hdmtt, priopćenja 1, varaždin, 1995. hrvatsko društvo za mehaniku tla i temeljenje, 367−376. jurak, v., matković, i., miklin, ž. & mihalić, s. (1996): data analysis of the landslides in the republic of croatia: present state and perspectives.− in: senneset, k. (ed.): landslides. 7th international symposium on landslides, proceedings 3, trondheim, 1996. a.a. balkema, 1923−1928. jurak, v., matković, i., miklin ž. & cvijanović, d. (1998): landslide hazard in the medvednica submountain area under dynamic conditions.− in: marić, b., lisac, z. & szavitsnossan, a. (eds.): geotechnical hazards, xi. danube-european conference on soil mechanics and geotechnical engineering, proce edings, poreč, 1998. a.a. balkema, rotterdam, 827−834. benac, č., arbanas, ž., jardas, b., kasapović, s. & jurak, v. (1999): složeno klizište u dolini rječine.− rudarsko-geološkonaftni zbornik, 11, 81−90. jurak, v. & belošević, v. (1999): postojanost maceljskih pješčenjaka.− in: jašarević, i., hudec, m. & vujec, s. (eds.): znanstvenostručno savjetovanje mehanika stijena i tuneli, zbornik radova, 1, zagreb, 1999. građevinski fakultet i rudarsko-geološkonaftni fakultet sveučilišta u zagrebu, 47–52. jurak, v., kvasnička, p., dujmić, d. & kuk, v. (1999): seizmička podina u nizinskom dijelu grada zagreba.− in: bajić, a. (ed.): znanstveni skup “andrija mohorovičić − 140. obljetnica rođenja“, zbornik radova, zagreb, 1998. državni hidrometeorološki zavod, 125−139. benac, č., arbanas, ž., jurak, v., kasapović, s., dujmić, d., jardas, b. & pavletić, lj. (2000): klizište grohovo − složeno klizanje u dolini rječine.− in: vlahović, i. & biondić, r. (eds.): 2. hrvatski geološki kongres, zbornik radova, cavtatdubrovnik, 17–20. svibanj 2000. institut za geološka istraživanja, 517−523. biondić, b., mayer, d., braun, k. & jurak, v. (2000): geološko inženjerstvo: stanje i perspektive.− in: vlahović, i. & biondić, r. (eds.): 2. hrvatski geološki kongres, zbornik radova, cavtatdubrovnik, 2000. institut za geološka istraživanja, 7−9. jurak, v. & fabić, z. (2000): erozija kišom u slivu bujičnog vodotoka u središnjoj istri.− in: vlahović, i. & biondić, r. (eds.): in: vlahović, i. & biondić, r. (eds.): 2. hrvatski geološki kongres, zbornik radova, cavtat-dubrovnik, 2000. institut za geološka istraživanja, 603−612. jurak, v. & šestanović, s. (2000): hidrogeološki i inženjer skogeološki prikaz odabranih lokaliteta u području dubrovačkog primorja − postaja 3: most preko rijeke dubrovačke.− in: vlahović, i. & biondić, r. (eds.): 2. hrvatski geološki kongres, vodič ekskurzija. institut za geološka istraživanja, zagreb, 25−29. jurak, v. (2000): torrential catchment raindrop erosion in the central istria (croatia).− in: carulli, g.b. & longo salvador, g. (eds.): 80a ruinione estiva, riassunti delle comunicazioni orali e dei poster, trieste, 2000. edizioni universita di trieste, 296−298. petraš, j. jurak, v. & gajski, d. (2001): istraživanje ekscesivne erozije na golim fl išnim padinama u istri primjenom terestričke fotogrametrije.− in: racz, z. (ed.): x. kongres hrvatskog tloznanstvenog društva s međunarodnim sudjelovanjem: gos podarenje i zaštita tla za buduće generacije, sažeci, brijuni, 2001. hrvatsko tloznanstveno društvo i agronomski fakultet sveučilišta u zagrebu, 110−111. benac, č., arbanas, ž., jardas, b., jurak, v. & kovačević, m.s. (2002): complex landslide in the rječina river valley (croatia): results and monitoring.− in: rybar, j., stemberk, j. & wagner, p. (eds.): landslides. 1st european conference on landslides, proceedings, prague, 2002. a. a. balkema publishers, 487−492. jurak, v., petraš, j. & gajski, d. (2002): istraživanje ekscesivne erozije na ogoljelim fl išnim padinama u istri primjenom terestičke fotogrametrije.− hrvatske vode, 10/38, 49−58. mihalić, s., kvasnička, p. & jurak, v. (2002): identifi kacija i opis stijena i tala u geotehnici.− in: mulabdić, m. (ed.): geotehnika kroz eurocode 7, 3. savjetovanje hrvatske udruge za mehaniku tla i geotehničko inženjerstvo, priopćenja, hvar, 2002. hrvatska udruga za mehaniku tla i geotehničko inženjerstvo, 321−332. mihalić, s., žugaj, r. & jurak, v. (2002): the infl uence of heavy rainfall on the landslide initiation. in: holz, p., kawahara, m. & wang, s. (eds.): advances in hydro – science and engineering. 5th international conference on hydro science and engineering, proceedings 5, warsaw, 2002. warsaw university of technology, 99, 18–20. aljinović, d., jurak, v. & kompar, d. (2003): compositional variations and origin of glauconite-bearing sandstones (macelj formation, nw croatia).− in: vlahović, i. (ed.): 22nd ias meeting of sedimentology, abstracts book, opatija, 2003. institute of geology, p. 5. jurak, v., petraš, j., gajski, d. & aljinović, d. (2003): field intensity measurements of erosion instability in fl ysch deposits in istria, croatia.− in: natau, o., fecker, e. & pimentel, e. (eds.): international symposium on geotechnical measurements and modeling, proceedings, karlsruhe, 2003. a. a. balkema publishers, 283–289. miklin, ž., jurak, v., slišković, i. & dolić, m. (2003): geotehnical hazard evaluation of the medvednica nature park.− in: petrič, m., pezdič, j., trček, b. & veselič, m. (eds.): international conference groundwater in geological engineering, proceedings, bled, 2003. rmz materials and geoenvironment for mining, metallurgy and geology, 50, 241−245. juračić, m., palinkaš, l., bajraktarević, z., buljan, r., bergant, s., jurak, v., gušić, i., marjanac, lj., marjanac, t., matičec, d., mezga, a., paviša, t., šestanović, s., šoštarić-borojević, s., strmić, s., sremac, j., tišljar, j. & vlahović, i. (2004): adriatic– dinaridic mesozoic carbonate platform, environments and facies from permian to recent time.− in: guerrieri, l., rischia, i. & serva, l. (eds.): 32nd international geological congress, proceedings and field trip guide book, apat − italian agency for the environmental protection and technical services, roma, 1−48. jurak, v., ortolan, ž., slovenec, d. & mihalinec, z. (2004): verifi cation of engineering-geological/geotechnical correlation column and reference level of correlation (rnk) method by observations in the slip-plane zone.− geologia croatica, 57/2, 191−203. mileusnić, m., slovenec, d. & jurak, v. (2004): thenarditeeffl orescence indicating cause of the excessive fl ysch erosion, slani potok, croatia.− in: nemeth, t. & terbocs, a. (eds.): 2nd mideuropean clay conference, szeged miskolc, 2004. acta mineralogica-petrographica, abstract series., department of mineralogy, geochemistry and petrology, university of szeged, p. 75. žugaj, r., plantić, k. & jurak, v. (2004): mean annual discharges in covered croatian karst.− in: hladni, j. (ed.): 12nd conference of danubian countries on the hydrological forecasting and hydrological bases of water management, conference abstracts 2, brno, 2004. chech hydrometeorological institute, p. 215. benac, č., arbanas, ž., jurak, v., oštrić, m. & ožanić, n. (2005): complex landslide in the rječina valley (croatia): origin and sliding mechanism.− bulletin of engineering geology and the environment, 64/4, 361−371. čedomir benac, snježana mihalić & tomo novosel: in memoriam professor vladimir jurak (1942–2010) geologia croatica 277 benac, č., jurak, v. & oštrić, m. (2005): qualitative assessment of geohazard in rječina valley.− geophysical research abstracts, 7, 08943, 1−6. benac, č., jurak, v., oštrić, m., holjević, d. & petrović, g. (2005): pojava prekomjerne erozije u području slanog potoka (vinodolska dolina).− in: velić, i. vlahović, i. & biondić, r. (eds.): 3. hrvatski geološki kongres, knjiga sažetaka, opatija, 2005. institut za geološka istraživanja, 173−174. biondić, r., biondić, b., jurak, v., kapelj, s., marković, t., miklin, ž., mileusnić, m., mlinar, ž., pavičić, a., slovenec; d. & štefanek, ž. (2005): ekskurzija b1 – krški dinaridi: hidrogeologija i inženjerska geologija.− in: biondić, r., vlahović, i. & velić, i. (eds.): vodič ekskurzija. hrvatsko geološko društvo, hrvatski geološki institut, prirodoslovno-matematički fakultet, rudarsko-geološko-naftni fakultet, ina-industrija nafte d.d., zagreb, 49−75. arbanas, ž., benac, č. & jurak, v. (2006): causes of debris fl ow formation in fl ysch area of north istria, croatia.− in: lorenzini, g., brebbia, c.a. & emmanouloudis, d.e. (eds.): monitoring, simulation, prevention and remediation of dense and debris flows, wit transaction on ecology and the environment, 90, 283−294. benac, č., jurak, v., oštrić, m. & ožanić, n. (2006): qualitative assessment of geohazard in the rječina valley, croatia.− in: culshaw, m., reeves, h., spink, t. & jefferson, i. (eds.): 10th iaeg international congress: iaeg engineering geology for tomorrow’s cities, proceedings, nottingham, 2006. the geological society of london, 1−7. benac, č., jurak, v., oštrić, m., arbanas, ž. & pavletić, lj. (2006): nestabilnost padina i geološki hazard u dolini rječine.− in: szavitz-nossan, v. & kovačević, m.s. (eds.): 4. savjetovanje hrvatskog geotehničkog društva: ojačanje tla i stijena, priopćenja. opatija, 2006. hrvatsko geotehničko društvo, 421− 428. jurak, v., pfaff, s., horvat, k. & krklec, n. (2006): provjera hipoteze o homogenosti geotehničkih sredina na lokaciji „čađare“ u kutini.− rudarsko-geološko-naftni zbornik, 18, 29−41. jurak, v., slovenec, d. & mileusnić, m. (2006): excessive fl ysch erosion − slani potok.− in: vlahović, i., tibljaš, d. & durn, g. (eds.): 3rd mid-european clay conference, field trip guidebook, opatija 2006. pagigraf, zagreb, 48−51. jurak, v., aljinović, d., mileusnić, m. & presečki, f. (2008): ovisnost sastava fl iša i pretjerane erozije slanoga potoka (vinodolska dolina), hrvatska.− in: filipović, a. (ed.): iii savjetovanje geologa bih sa međunarodnim učešćem, zbornik sažetaka, neum, 2008. udruženje/udruga geologa bosne i hercegovine, 78−79. jurak, v., ortolan, ž., ivšić, t., herak, m., šumanovac, f., vukelić, i. & jukić, m. (2008): geotehničko i seizmičko mikrozoniranje grada zagreba − pokušaji i ostvarenje.− in: radić, j. (ed.): zbornik radova konferencije razvitak zagreba, zagreb, 2008. secon hdgk, 99−108. ortolan, ž., jurak, v., ivšić, t., herak, m. & vukelić, i. (2008): geotehničke okolnosti − rubni uvjet održivog razvitka “podsljemenske urbanizirane zone”.− in: radić, j. (ed.): zbornik radova konferencije razvitak zagreba, zagreb, 2008. secon hdgk, 273−284. veinović, ž., kvasnička, p. & jurak, v. (2008): geohazardno obilježje prisavske ravnice na području zagreba.− in: radić, j. (ed.): zbornik radova konferencije razvitak zagreba, zagreb, 2008. secon hdgk, 259−266. benac, č., dugonjić, s., arbanas, ž., oštrić, m. & jurak, v. (2009): the origine of instability phenomena along the karstfl ysch contacts.− in: vrkljan, i. (ed.): rock engineering in diffi cult ground conditions − soft rock and karst, eurock 2009. regional symposium of the international society for rock mechanics, proceedings, cavtat, 2009. crc press/balkema, 757−762. miklin, ž., jurak, v., slišković, i. & dolić, m. (2009): heuristic approach by geotechnical hazard evaluation of medvednica nature park.− rudarsko-geološko-naftni zbornik, 21, 1−10. aljinović, d., jurak, v., mileusnić, m., slovenec, d. & presečki, f. (2010): the origin and composition of fl ysch deposits as an attribute to the excessive erosion of the slani potok valley (salty creek), croatia.− geol. croat., 63/3, 313−322. geologia croatica 64/3geologia croatica 278 geol . croat. 49/2 283 288 5 figs. i i i zagreb 1996 i scientific paper dipmeter interpretation more accurate structural definition of the ponti an sandstones of lipovljani and jamarice jurica nov ak ', .josipa velic', bozidar jancikovic' and bruno saftic' proceedings key words: dipmclcr inte rpre tation, descriptive stat is­ ti cs, orientation of fauil s, fault characterisation, pontian sandstones, lipovljani, jamarice, sava depression, croatia. abstract two pairs of wel ls have been chosen from the l ipovljani and jamaricc oil fields in lhe sava depression il1111e south-west part of the pannonian basin. both we ll s from each field have a measu red e-log, and one al so has a high-quality diplog. t he reservo ir rocks afc repre­ sent ed by folded and faulted pontian sandstones . a combination of grap hical int erpre tation and scat (sta ti stical curvature analy sis tec hniqu cs) has allowcd identification of both structural and fault plane dips . defining the position of fault plancs cnabled thc charac­ terisation of normal and reverse faults, incli ncd in thc direc lion of stmctural dip (or against il) , and positioned either longi tudinal , trans­ verse or d iagonal to the st ruclllre. the dcscribcd tcchnique can bc ful­ ly utilised in the crea tion of a gco logical modcl aimcd to finding the bypassed oil. i, introduction from th e late seven ties to th e early eighti es ina , the croatian national oi l-company purchased logging equ ipment from "western atlas", including the four­ pad high -reso lution dipmeter. in addition to giving an ana logue output recorded on film , this equipment is capable of digital recordin g of data, and thus enables computer data-process ing. dipilleter measurements were taken in several well s of li povljan i and jamarice fie ld s. the physical and lithological characte ri sti cs of the pontian sandstones, reservoir rocks in the aforementioned fi elds, resulted in good quality data with very c losely spaced dip mea­ surements. thi s suggested a mcthod for thc recognition and more accurate location of faults , and the ir orienta­ tion and influence on the gcomctry of rescrvoir rocks. two iypical we ll s from each field have bcen chosen to illustratc the mc thod. the results of various statistical curvature analysis techniques arc given, and show the success ful defin ition of structural dips (dips of bedding i lna -naftap lin. subiceva 29, hrt 0000 zagrcb, cro;jl ia. kljucne rijeci: interpre tacija dipmetra, deskriptivna statistika, orijentacija rasjeda, karakterizacija rasje­ cia, pontski pjescenjaci, lipovljani, jamarice, savska depresija, f-irvatska. sazetak s naftnih potja lipov lj ani i jam aric e iz savs ke depresije u jugozapadnom dijclu panonskog bazena odabranc s u po dvij c bu solinc s c leklrokarolazn im dijagramima od kojih po jedna ima jos i vrlo kva litetan diplog. ovdje su kolektori, pontsk i pjescenjaci, bor-ani i rasjedani. kompteksnom interpre tac ijom grafickom i statistickom (scat) , razlu ce ni sll nag ibi sloj eva od nagiba paraklaza. ulv rd eni cleme nti orijentacije rasjeda omogucili su njihovu karakt e rizacij u na normalne iii reverznc, na prolusmjernc ii i is losmjernc, te na uzcluznc, poprecne iii dijagonalne. tako dobivena !j esenja nezaob ilazna su pri kreiranju geolos kog modet a s ciljem pronalazenja 7.aostalc !lafte. planes), and their separation from differently spaced planes caused by tectonic deformation fa ult planes presented by e ither simple surfaces or fault zones. the oil fields of lipovljani and jamaricc arc located some 90 km east of zagreb (fig. ib), in the south­ western part of the pannonian basin, in the sava depres­ sion. in j 932 the first oil and gas ex plorati ons took place there . uplifted structures were defined by seismic reflection lines in 1959. the drilling on lipovljani com­ mcnced in 1960, and on .tamaricc in 1964. in accor­ dance with regional lithostratigraphic subdivi sion the productive hori7.on s were named janj a lipa, kozarica and bujavica sandstones (figs. la, 4a), which chronos­ tratigraphi ca lly fairly closcly rcspond to the ponti an deposits. the observable signs of fauliing in the menti oned fie lds had prcviollsly drawn thc attention o f explo­ rationists during the earl y 1970 's. this was then docll­ mented by a detailed study of conventional e-iogs, and the cases where the same layers were be ing repeatedly drilled th rough in one wcll, or an apparent hiatus in a 2 university of zagreb, facul!y of mining , geology & petroleum engi neering , pi erotlijeva 6, p.o. box 186, hr -i 0000 zagrcb, croatia. 284 lip-63 lip-123 well nearby were explained by tectonics (tufekcic, 1970; hernitz & simon, 1975; jancik oyic, 1977)_ 2. results of dipmeter analysis the dip log of well li p-123 has been chosen from the field li pov ljani together with e-log of lip-63 fo r correlalion purposes . the depth interval from 1000 to 1350 m is shown (fig. la). correlation of log-measure­ ments (ni6, n64, sp) from these closely spaced wells depicts substantial differences in the lithological cotnlocat ion map l . b . sea l e ~oom. llpovljani up.-123 r, polar plot azimuth dip 270 1-----------­ . 1000-1063 . ' 1064-1080 . 1081-115~ l.c. depth interval m llpovljani lip-123 r2 polar plot azimuth dip 270 1_ 1230-1281 . 1282-1312. 1312-1360 i 1.d. depti-iinterval (m) legend bujavica sandstone kozarica sandstone janja llpa sandstone repeat section r-fault geologia croalica 49/2 fig. i a) correl31ion scheme lip63 wel! lip-123 well; b) location map: c) lip123 well r, azimuth dip plol: d) lip123 well r2 azimuth dip plot. position and thickness of individual sandstone bodies. it is, [or example, not iceable that the bujavica sandstone drilled by lip-63 well was totally absent in lip-123_ in contras t, the janja lipa sandstone is some 20 m thi nner in lip-63 than li p-123. the dip plot of lip-123 clearly shows a change of dip angle and azimuth in two pos i­ tions (fig. i a) . on the polar plots o[ az imuth and dip o[ planar eiemems from chosen intervals (figs. 1 c and i d) a concentrati on of patterns is apparent, illus trating the structural dip in the hanging wall and in the footwall, together wi th the orientation of the fau lt plane itself. this way of dip plotting doesn '1 show the depth of indi­ vi dual di ps, which is possibly confusing to less experinovak. velie. jaocikovic & saftic : dipmeler inlerprel;llion more aeeur:lie slruclllr;t1 definition ... 285 ,",~"'h ,., ,~" ,"~ 23 scat and stick plot iiip ,'~ ill""',. enced analysts. the "azimuth vs. dip" cross-plot allows singular dips to be traced to their precise depth so that their "origin" can be controlled. generall y speaking, in th is way patterns analysed with the help of" a cross-plol will show a gauss normal distribution , whereby dips from one side of the [aull or another are put into one or more stochastic groups. in the case of lip123, not only a ve rt ical but al so a horizontal di splacement can be deduced from the differences in the dip azimuth (fig. 2). furthe011ore, it is only possible by cross-plot to pre­ cisely define the position of the transverse and longitu­ di nal plane, marked by st ruclural d ip and well axis. a series of related c ross-piois is shown on fig. 2. these arc: mercator projection of azimuth vs. depth, "dip vs. dept h", the transverse and longitudinal dip component vs. depth and the two most characteristic perpendicular sti ck plot s vs. depth . thorough analysis of the cross­ plot s allowed ca lculation of the thi ckness of the deformed inlervals and, more importantly, the dip and " i~ i'i'i vi l w ..... , ~'s i.':;" '" va" i fiqn "os fig. 2 lip 123 well r, scat and slick plm. azi muth of fault planes. ]n lip ~ 123 two faults are docu­ mented r, with a fault plane 125/50 on 1070 m and r, positioned 190/60 on 1298 m. the first fault is younger, nonnal , inclined against the structu ral dip and diagonal to the structu re (fig. 3), the o ther is o lde r, probably reverse, inclined in the same direction as the st ructural dip but steeper than bedding dip values. well -log correlation be tween 1am-74 and jam160 showed marked differences in sandstone thickness (fig. 4a). the dip plot of jam 160 shows well-marked di s­ continuities of both dip and azimuth al deplhs corre­ sponding 10 the pos iti ons of reduced sandstone thick­ ness as defi ned by e-iog correlation with jam-74. these discontinuities are also observable on the mercator pro­ jection of azimuth vs. depth, as well as on the "d ip vs. depth" plot (fig. 5). it is al so noticeable that both the transverse and longitudinal dip component have similar di scontinuities at the same depths. the patterns at j203 and 1250 m have an inclination opposite to the disconti cross section lip-63 lip-123 lip-63 lip-1 23 d sujavica sandstone i ?1normal »" fault iiiiiiiiiiikolarica _ sandstone t .:-.: ireverse -'::-. fault fig_ 3 cross sec lion lip-63 well lip-123 well. ~janjalipa !l..±2:lisandstone ~repeat _ section nuities located at 1280. 1308 and 1355 m respectively. this is due to the spatial position of faults that arc appropriately shown in the chosen sections . figures 4b, c, d, e and f show azimuth vs. dip cross-plots from jam160. the positions of fault planes are as fol1ows: r] with 220/55 at 1203111, r2 with 290/45 at 1250 m, r3 with 145/50 at 1280 m, r4 with 75/45 at 1308 m and r, with 90/65 at 1355 m. based on the relationship between the structural dip and orientat ion of fault planes, faults r] and r2 arc diagonal with fault planes inclined in the same direction as the structural dip, r3 and r" are diagonal with inclination again st the struc­ tural dip, while rault rs is longitudinal to the structure and inclined against the structural dip. all the faulls have 110rmal displacement. these solutions are essential in finding the so-called "bypassed oil", especially in the phase of building a complex geological model (bassiouni & yelic, 1996; prelogoyic et ai., 1995) in order to explore for oil and gas morc economi­ cally. 3. conclusion the interpretation of very dense dipmeter data requires certain skill and experience. only by utilisation of a number of graphical and statistical techniques can satisfactory and unambiguous results be obtained. examples of two pairs of wells from the lipovljani and jamarice fields, with intensively rolded and faulted sandstone reservoirs, are uscd for ihe illustration of how structural dips can be discerned from the fault planes; how the fault plane oriej1lalion can be defined; and finally how the character of a fault can be deduccd. geologia cwatica 49(2 4. references bassiouni, z. & yelic, j. (1996): prospecting for bypassed oil and gas.geol. croat., 49/2, proceed­ ings of i st internat ional symposium of petroleum geology, 1.97-202. hernltz, z. & simon, j. (1975): rasjedi i izrada karata debljina naslaga (faults and preparalion of isopach maps). zbornik radova rud arsko-gco lo­ sko-naftnog fakulteta sveucilista u zagrcbu u povo­ du 35 god. rada, 77 -85, zagreb. jancikoyic , b. (1977): principi mjerenja pad a sloje­ va u busotinama i mogucnost definiranja prostorne orijcntacije rasjeda u neogenim slojevima jugoza­ padnog dijcja panonskog bazena (principles of dip logging and the possibility of determining the spa­ tial orientation of faults in neogenc deposits in the south-western part of the pannonian basin).­ zborn ik radova ill. godisnjeg skupa znanstvcnog savjeta za naftu jugoslavenske akademije znanosli i umjetnosti, 171-207, novi sad . prelogovic, e., jamicic, d., aljinoyic, b., yellc, .t., saftic, b. & dragas, m. (1995): dinamika nastanka struktura juznog dijela pan on­ skog bazena.in: ylahoyic, i., yelic, i. & sparica, m. (cds.): first croatian geological congress, proceedings, 2,481-486, zagreb. tufekcic, d. (1970): 0 revcrsnom rasjedanju struk­ lure lipovljani (compression type of reverse faulting in lipovljani structure).nafta, 21/3, 99104, zagreb. nova\... velie. j:lilc ikovic &. sanie: diplllclcr imcrprc[:l[ion more accurate stnlcturnl derini[ ion .. 287 jom-74 ~ joml bo sp cj c::j o o '00 n[t. 20n64 20.2 o sp '00 o o legend nl6 20 "" '" 0 90 bujavtca sandstone cd kozarica 2 sandstone r faun kozarica 1 sandstone g:;gj janja l1pa sandstone ---------------------------' . b 4 .c . 4 . d . " . 4 ,i. · · " • • .. • • .. '. • • " • ~i .. '. jamarice jam-160 azimuth vii dip cross plot ~ • o ip a1:imthii • "oo,,~~ . 11~'w3 . ':1(><-12<01 olp t" i'h e rval .,jamarice jam·160 azimuth ys dip cross plot r, i . a to '80 ,1ti dip ai im u tii • ' 2, (l.'2« 1 • ,2<2· ,250 . ' 25'·'~ oepth inter val 1ti'} jamarice jam -t oo azimuth v5 dip cross plot r, 'i ,.;--~=;-~.~ d ip a7. imihh • 1~127e • 1271-12s , . '2b2· , :lq2 deptii interval (m· jamarice jam-t60 azimuth vii, dip cross plot r, ~l .. '. j .. • • " • • .• d ip aiiiiiutii jamarice jam-160 azimuth vii. dip cross plot r. · . .. : .. -'0 .­ '. • '" dip az imut h d ep th interval (.,1 fi g. 4 a) corre lation scheme jam-74 we ll jarn-160 well: b) jam160 wel l r i azimut h vs. dip cross plol: c) jam-l 60 well r2 az imuth vs. dip cross plot: ei) jam-160 we ll rj<lzimuth vs. clip cross plot: c) ja111-l60 wei) r" az imuth vs. dip cross pial; f) jarn160 well rs azim uth vs. dip cross 1'101. jam-160 scat and stick plot n n ( it!ologla cro,li u.:a 4'j(l fig. 5 jalll160 well rj-rt -r,l scat and slick piol 2017 | 70/1 | 1–10 | 2 figs. | 2 tabs. | 4 pls. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the fossil-genus neuralethopteris cremer is characterised by neuropteroid pinnules that have cordate bases and alethopteroid venation (goubet et al., 2000). representatives of neuralethopteris are widespread in the euramerican realm, and are important biostratigraphic indicators in upper namurian and lower westphalian strata. neuralethopteris schlehanii (stur) cremer, the type and most common species of neuralethopteris, occurs in euramerica, although 10 other fossil-species are known (five each from europe and north america) (cleal & shute, 1995, goubet et al., 2000 tenchov & cleal, 2010). to date, n. schlehanii is the only member of the fossil-genus for which cuticles have been studied (cleal & shute, 1992). during a visit to wrocław university in poland to study the type material of cordaites palmaeformis (göppert) weiss (šimůnek, 2015), some pinnules of neuralethopteris were found on the same slab as one of the syntypes of c. palmaeformis and sampled for maceration. the pinnules were identified as neuralethopteris jongmansii laveine, which is relatively rare in the intrasudetic basin and has yet to be determined in the czech part of the basin. in this paper, a detailed cuticular analysis is presented for n. jongmansii, which represents only the second species of neuralethopteris for which cuticles are known. 2. material and method the syntype of cordaites palmaeformis, from which the pinnules of neuralethopteris jongmansii were collected, came from the wałbrzych locality, intrasudetic basin, poland. the syntype slab is stored in wrocław university under no. 1667p. although the exact horizon and stratigraphic level from which the syntype slab cuticular characteristics of neuralethopteris jongmansii laveine (medullosalean foliage, westphalian, intrasudetic basin, poland) zbyněk šimůnek czech geological survey, klárov 3/131, 118 21 praha 1, czech republic; (zbynek.simunek@geology.cz) doi: 10.4154/gc.2017.02 abstract foliar cuticles are described for the first time from the medullosalean pteridosperm neuralethopteris jongmansii laveine. this species is not as common, either in abundance or distribution, as neuralethopteris schlehanii (stur) cremer, the abaxial cuticle of which has paracytic (in morphological sense) and anomocytic stomata. in contrast, the stomata of neuralethopteris jongmansii occur on both abaxial and adaxial cuticles and are anomocytic, monocyclic with prominent proximal papillae and sometimes paracytic. the epidermal cells of n. jongmansii are papillate and partly differ from n. schlehanii cuticles. however, there is a striking similarity between the foliar cuticles of n. jongmansii and neurodontopteris auriculata (brongniart) potonié. although n. auriculata is a much younger fossil-species with pinnules that are more robust and of a different shape than n. jongmansii, their epidermal structures are practically the same – polygonal papillate cells, anomocytic, monocyclic stomata with prominent proximal papillae. even their stomatal densities are equivalent. despite this, there is a marked difference in the frond architecture of both genera. neuralethopteris has „alethopterid“ bifurcate-pinnate frond architecture, neurodontopteris has quite a different bifurcate-semi-pinnate frond architecture. based on comparison of the cuticles, neuralethopteris jongmansii and neurodontopteris auriculata appear very similar and it may reflect common palaeoenvironmental demands. was collected is not known, the fact that other occurrences of n. jongmansii in europe are in langsettian (lower pennsylvanian) strata (cleal et shute, 1995) suggests that it probably came from the lower part of the žacléř formation (table 1). the cuticles were prepared by a standard maceration method using schulze’s reagent, as described by kerp (1990), krings & kerp (1997) and kerp & krings (1999). 3. geological setting the intrasudetic basin extends from the north-eastern czech republic into south-western poland, where the wałbrzych locality is located (fig. 1). mississippian strata of the intrasudetic basin are largely coarse-grained siliciclastics that reach 5 km in thickness. sedimentation changed at the end of the mississippian, after which the coal-bearing wałbrzych formation was deposited. it reaches up to 250 m thickness, and is of serpukhovian and earliest bashkirian (lower namurian) age. the overlying coal-barren biały kamień formation is up to 380 m thick and largely comprises sandstones and conglomerates. in the polish part of the intrasudetic basin, the lower part of the overlying žacléř formation (upper bashkirian, langsettian and duckmantian) is coalbearing. the study samples probably come from this stratigraphic level, a conclusion supported by the fact that coals of the žacléř formation were mined in the vicinity of wałbrzych. the uppermost bashkirian (duckmantian) part of the formation only contains a few workable coal seams in the polish part of the basin. the moscovian and kasimovian (upper westphalian and lower stephanian) glinik formation, which reaches 850 m in thickness, is practically devoid of workable coal seams. the uppermost formation in the polish part of the basin is the ludwikowice formaarticle history: manuscript received may 30, 2016 revised manuscript accepted november 23, 2016 available online february 20, 2017 keywords: neuralethopteris, cuticular analysis, westphalian, poland, intrasudetic basin ide cb g eo lo gi a c ro at ic a geologia croatica 70/12 tion, which reaches 440 m thickness and largely comprises coarse-grained redbeds of gzhelian (late stephanian) and asselian (early permian) age (table 1.) (bossowski et al., in zdanowski & żakowa, 1995). 4. systematics order medullosales corsin, 1960 family alethopteridaceae corsin, 1960* fossil-genus neuralethopteris cremer, 1893 emend. laveine, 1967 type species: neuralethopteris schlehanii (stur, 1877) cremer, 1893 *family alethopteridaceae is based on frond architecture that is an ancillary feature, however a natural botanical system should be based on fructifications. such a family is the trigonocarpaceae seward, 1917 family, but plants with different frond architectures can have trigonocarpalean seeds. so the alethopteridaceae family is an artificial family from this point of view. neuralethopteris jongmansii laveine, 1967 1967 neuralethopteris jongmansii laveine: p. 107–112, pls. 2–4. 2010 neuralethopteris jongmansii laveine; tenchov & cleal: 2010, p. 303, pls. 1, figs. 5, 6. description: two pinna fragments up to 35 mm long, together with several isolated pinnules are preserved on the edge of specimen 1667p. pinnules are small, being 5–8 mm long and usually 2–3 mm wide, and have a cordate, asymmetric base and a thick midvein that nearly extends to the pinnule apex. lateral veins arise oblique to the midvein and arch broadly to meet the pinnule margin at 80–90°. each lateral vein generally forks twice, resulting in a high vein density of 60–80 veins per cm on the pinnule margin. adaxial cuticle: stomata are present in the intercostal fields but absent in the costal fields. ordinary cells are polygonal, 40–80 (100) mm long and 30–45 mm wide, and slightly elongated in the costal fields. a small papilla, up to 10 mm in diameter, is present in the middle of each cell. stomatal complexes are 60–70 mm in diameter, and comprise two guard cells and five or six small polygonal subsidiary cells that are 25–40 mm long and 15–30 mm wide. cutinisation of papillae on the subsidiary cells is stronger than cutinisation of papillae on ordinary cells. these papillae are also longer, up to 15 mm wide, and oriented (bent) towards the guard cells (proximal papillae). hydathodes (pl. i/j) are 40–45 mm in diameter and situated at the edge of pinnules. stomatal density varies from 40–50 stomata per mm2 and the stomatal index ranges from 8–10. abaxial cuticle: abaxial cuticles are very similar to adaxial cuticles. stomatal complexes are generally monocyclic, anomocytic, but some stomata can be also paracytic in a morphological sense (pl. ii/i). polygonal cells are 30–80 mm long and 20–40 mm wide, and stomata are practically the same as those on adaxial cuticles. stomatal density varies from 50–65 stomata per mm2 and the stomatal index is between 8–10, similar to the values for adaxial cuticles. trichome bases, surrounded by six or seven ordinary cells, occur in the area that is presumed to correspond to the midvein (pl. ii/b,c,g,h). trichome bases are circular to slightly oval and their margins are strongly cutinised. no hairs have been observed. also occurring in these areas are stomata-like features (pl. ii/g,h), which are oval and surrounded by eight small cells, although no guard cells have been observed. 5. comparisons the first descriptions of cuticles of the fossil-genus neuralethopteris were made by cleal & shute (1992), who noted that cuticles of the type species neuralethopteris schlehanii have an unusual type of paracytic stomatal structure that was previously unknown in the medullosaleans. but cleal (pers. com. 2016) admitted that the abaxial cuticle of neuralethopteris schlehanii was fragmentary in preservation, and some stomata can be interpreted as anomocytic, the others as paracytic. a stoma of neuralethopteris jongmansii figured on pl. ii/i resembles the paracytic type. nevertheless, the cuticles of neuralethopteris jongmansii differ from those of n. schlehanii (table 2.), namely by the adaxial cuticle. in contrast to neuralethopteris schlehanii, n. jongmansii also has stomata on the adaxial cuticle which represents amphistomatic foliage, a feature that, among the medullosaleans, is only known for the monotypic fossil-species neuro dontopteris table 1. stratigraphy of the polish part of the intrasudetic basin with emphasize to the pennsylvanian strata. global scale regional scale formation permian asselian     ludwikowice pe n n sy lv an ia n gzhelian stephanian c kasimovian b glinik barruelian cantabrian moscovian westphalian asturian bolsovian žacléř  bashkirian duckmantian langsettian biały kamień namurian yeadonian marsdenian kinderscoutian wałbrzych alportian chokierian mississippian serpukhovian arnsbergian pendleian viséan       tournaisian        probable location of studied sample figure 1. a map of poland showing the locality of wałbrzych (black square). g eologia c roatica zbyněk šimůnek: cuticular characteristics of neuralethopteris jongmansii laveine (medullosalean foliage, westphalian, intrasudetic basin, poland) 3 auriculata (brongniart) potonié (krings, 1999, šimůnek, 1999). the cuticles of these two fossil-species are also strikingly similar. pinnules of neuralethopteris jongmansii and neuralethopteris schlehanii have comparable dimensions, but their vein densities differ, with n. schlehanii having 36–48 veins per cm on the pinnule margin and n. jongmansii having 50–60 (tenchov & cleal, 2010). the studied samples had 60–80 veins per cm. these two species also differ in the course of the lateral veins and other features. although n. schlehanii is hypostomatic and n. jongmansii is amphistomatic, they have anomocytic, monocyclic stomata. some stomata can be interpreted as paracytic, as in cleal & shute (1992). the abaxial cuticles of both species differ in the following features: stomatal densities of ca. 300 per mm2 in n. schlehanii and ca. 50–65 mm2 in n. jongmansii, and whereas the cells of n. jongmansii are papillate, the cells of n. schlehanii are not. it is debatable whether this is the result of the poor preservation of the second species. these features can be used by distinguishing of both species. figure 2. venation diagram of a pinnule of neuralethopteris jongmansii laveine. scale bar = 5 mm. table 2. important diagnostic features of the neuralethopteris species. species neuralethopteris schlehanii neuralethopteris jongmansii neurodontopteris auriculata pi nn ul es authors tenchov & cleal (2010) tenchov & cleal (2010) šimůnek (1999) length x width (mm) (4-15)x(2-4) (up to 13)x(4-5) (36-42)x(15-18) shape subtriangular, elongate linguaeform to subfalcate linguaeform tongue-shaped with basal lobe no. veins per pinnule margin 36-48 (50-60); (60-80) 35-40 cuticle authors cleal & shute (1992) this paper krings (1999); šimůnek (1999) pinnules hypostomatic amphistomatic amphistomatic ad ax ia l c ut ic le costal cells elongate to subrectangular ±elongate, polygonal ±elongate, polygonal size of costal cells (µm) up to 120 x up to 20 [40-80(100)]x (30-45) up to 100 x up to 45 intercostal cells irregularly polygonal irregularly polygonal irregularly polygonal size of intercostal cells (µm) up to 80 x up to 30 (40-80) x (30-45) up to 45 in the diameter form anticlinal walls ±straight ±straight ±straight palillae on periclinal walls – + + ab ax ia l c ut ic le costal cells elongate to subrectangular ±elongate, polygonal elongate tetragonal to polygonal size of costal cells (µm) up to 70 x up to 5 (30-80)x (20-40) (20-40) x (10-15) intercostal cells ? polygonal irregularly polygonal irregularly polygonal size of intercostal cells (µm) (up to 80) x (up to 20) (30-80) x (20-40) (30-50) x (10-25) form anticlinal walls ? slightly bent ±straight ±straight palillae on periclinal walls – + + st om at a distribution regularly arranged parallel to veins in the intercostal field mostly parallel to veins, some stomata random randomly oriented in the intercostal fields type ?paracytic, anomocytic; monocyclic anomocytic, ?paracytic; monocyclic anomocytic; monocyclic density per 1 mm2 ca. 300 40-50; 50-65 60-70 stomatal index 19 8-10 ? shape of guard cells ? reniform reniform length and width of guard cells (µm) cca 30 x 3 cca 30 x 7 (20-25) x (4-6);(25-35) x (5-10) dimension of stomatal complex (µm) ? 60-70 in the diameter 75-95 in the diameter subsi-diary cells number and shape 2 or more; ±oblong (polygonal) 5-6; polygonal (oblong), poximal papilae 5-6; polygonal, proximal papillae size (µm) ? (25-40)x(15-30) 35-50 in the diameter trichome bases (shape and dimension in µm)   circular; cca 25 in the diameter star-like; 40-55 in the diameter trichomes (shape and dimension in µm) unicellular; 120 x 15     hydathodes (shape and dimension in µm)   rounded on the pinnule margin; 40-45 in the diameter.   g eo lo gi a c ro at ic a geologia croatica 70/14 even though the morphology of neuralethopteris jongmansii and neurodontopteris auriculata differ, their cuticles are surprisingly remarkably similar. neuralethopteris fronds have an „alethopterid“ bifurcate-pinnate architecture (laveine et al., 1992, fig. 3). the fronds can be several metres long and do not have intercalary elements. the fronds of neurodontopteris auriculata are about 0.5 m long (langiaux, 1984, fig. 233) and have a bifurcate-semi-pinnate architecture. pinnules of n. auriculata have a basal lobe and are much larger and wider than pinnules of n. jongmansii (table 2). furthermore, n. auriculata occurs in much younger strata of stephanian b to early permian age. nonetheless, these two fossil-species are the only amphistomatic taxa known to date in the order medullosales. both have anomocytic, monocyclic stomata, strikingly similar papillate polygonal cells, stomata with proximal papillae, and similar adaxial and abaxial cuticles. even though occurrences of the two fossilspecies in the fossil record are separated by some 8 myr, their stomatal densities are comparable: 50–65 stomata per cm for the abaxial cuticle of n. jongmansii and 60–70 for n. auriculata (table 2.). in fact, the only distinguishing feature between the fossilspecies is the presence of star-like trichome bases (šimůnek, 1999) in n. auriculata, although the feature only occurs on a single (?adaxial) cuticle. on the whole, distinguishing these fossiltaxa would be very difficult if only dispersed cuticles were available and the age of the strata were not known. however, both genera differ in gross-morphology. the frond architecture of neuralethopteris is mainly based on neuralethopteris schlehanii (laveine et al., 1992), because the occurrences of neuralethopteris jongmansii specimens are rare and fragmentary. neurodontopteris auriculata belongs to plants with small stature (ši můnek, 1999). the dimensions of the neuralethopteris jongmansii plant are not known. due to the similarity of the cuticles with those of neurodontopteris auriculata¸ it probably was also of small stature (similar palaeoecological demands of both plants) in contrast to neuralethopteris schlehanii. 6. palaeobiology the presence of amphistomatic pinnules in medullosaleans is exceptional. šimůnek (1999) speculated that this feature, found in neurodontopteris auriculata, could point to a small-statured plant, having fronds that were protected from direct sunshine. neuralethopteris jongmansii also had some adaptation to living in the understory (stomata on both pinnule sides). proximal papillae on subsidiary cells around guard cells could prevent watter drops to enter the stoma opening. the adaxial and abaxial cuticles have approximately the same stomatal densities. both species are amphistomatic and have small papillae on periclinal cell walls. this probably helped the plant to get rid of water drops from the pinnule surface. neuralethopteris jongmansii and neurodontopteris auriculata probably lived in similar habitats. 7. conclusion (1) the morphology of neuralethopteris jongmansii pinnules is similar to those of neuralethopteris schlehanii, the latter is the type species of the fossil-genus neuralethopteris, although n. jongmansii has denser lateral veins that follow a slightly different course. (2) the pinnules of neuralethopteris jongmansii are amphistomatic and the pinnules of neuralethopteris schlehanii are hypostomatic. abaxial cuticles of both species are similar in stomatal types. n. jongmansii have anomocytic, monocyclic stomata, some stomata morphologically resemble the paracytic type and resemble those of n. schlehanii stomata. (3) based on cuticles, neuralethopteris jongmansii and neurodontopteris auriculata are strikingly similar, and are the only medullosaleans known to date with amphistomatic foliage. both fossil-species have the same type of stomata, cell shapes and stomatal densities, indicating life in similar environments. both plants were probably of small stature and probably lived in undergrowth. acknowledgement this paper was written with grant support from the grant agency of the czech republic, no. p210-12-2053. the author thanks the workers from the collections of the wrocław university in poland, dr. a. setlik, and dr. p. raczyński, for help with studying göppert’s collection. the author thanks dr. c.j. cleal (cardiff) for his advice concerning neuropteroids and his critical review of the text; and dr. a.r. bashforth for english editing of the text. w.a. dimichele gave as a second reviewer productive remarks that improved the manuscript. plate 1 neuralethopteris jongmansii laveine. loc. wałbrzych, „langsettian?“, coll. göppert, wrocław univ., inv. no. 1667 p. a – pinnule margin with adaxial cuticle on the left and abaxial cuticle on the right. slide 603/8. b – detail of abxial cuticle with stomata from fig. a. c – close up of fig. b with detail of stomata. d – adaxial cuticle on the left and abaxial cuticle on the right. slide 602/10. e – detail of abaxial cuticle with stomata from fig. d. f – adaxial cuticle with stomata. slide 456/4. g – close up of fig. f with stomata and cells with very small papillae. h – close up of fig. f with details of stomata and cells of intercostal field with very small papillae. i – detail of s stoma from fig. h. note the papillae arising from subsidiary cells. j – margin of adaxial cuticle with hydathodes. slide 456/5. k – close up of two hydathodes from fig. j. g eologia c roatica zbyněk šimůnek: cuticular characteristics of neuralethopteris jongmansii laveine (medullosalean foliage, westphalian, intrasudetic basin, poland) 5 g eo lo gi a c ro at ic a geologia croatica 70/16 plate 2 neuralethopteris jongmansii laveine. loc. wałbrzych, „langsettian“, coll. göppert, wrocław univ., inv. no. 1667 p. abaxial cuticles. a – two stomata with papillae on subsidiary cells. slide 602/9. b – ? probably an area of midrib with ?trichome basis. slide 602/10 c – close up of two trichome bases from fig. b. d – abaxial cuticle with stomata. slide 603/8 (cuticle from pl. i, a). e – close up of two stomata from fig. d. f – close up of a stomata from fig. d. note the papillae on subsidiary cells. g – ? probably midrib with trichome bases. slide 603/9. h – close up of trichome bases? from fig. g. i – close up of a stoma resembling the paracytic stomatal type. slide 602/11. j – abaxial cuticle with stomata. slide 603/7. references bossowski, a., ihnatowicz, a., mastalerz, k. kurowski, l. nowak, g.j. (1995): intra-sudetic depression.– in: zdanowski, a. & żakowa, h. (eds.): the carboniferous system in poland. prace państwowego instytutu geologicznego, 124–146, warszawa. cleal, c.j. & shute, c.h. (1992): epidermal features of some carboniferous neuropteroid fronds.– review of palaeobotany and palynology, 71, 191–206. doi: 10.1016/0034-6667(92)90162-a cleal, c.j. & shute, c.h. (1995): a synopsis of neuropteroid foliage from the carboniferous and lower permian of europe. bulletin of the british museum (natu-and lower permian of europe. bulletin of the british museum (natural history).– geology series, 51, 1–52. corsin, p. (1960): classification des ptéridophytes et des ptéridospermophytes du carbonifère. bulletin de la société géologique de france 2 (série 7), 566–572. cremer, l. (1893): über die fossilen farne des westfälischen carbons und ihre bedeutung für eine gliederung des letzeren. mitteilungen aus dem geologischen museum der westfälischen berggewerkschaftskasse, 1, 1–49. goubet, p., pfefferkorn, h.w. & gillespie, w.h. (2000): neuralethopterids (trigonocarpalean pteridosperms) from the early pennsylvanian of eastern north america.– paleobios, 20, 11–37. kerp, h. (1990): the study of fossil gymnosperms by means of cuticular analysis.– palaios, 5, 548–569. doi: 10.2307/3514861 kerp, h. & krings, m. (1999): light microscopy of cuticles.– in: jones, t.p. & rowe, n.p. (eds.): fossil plants and spores: modern techniques. geological society, london, 52–56. krings, m. (1999): zum bau der spaltöffnungsapparate von neurodontopteris auriculata (brongniart) potonié, einer pteridosperme aus dem stefan von blanzy-montceau (zentralfrankreich).– m�nstersche forschungen zur geologie und paläonto-(zentralfrankreich).– m�nstersche forschungen zur geologie und paläontologie, 86, 69–78. krings, m. & kerp, h.(1997): an improved method for obtaining large pteridosperm cuticles.– rev. palaeobot. palynol., 96, 453–456. doi: 10.1016/s00346667(96)00059-0 langiaux, j. (1984): flores et faunes des formations supérieurs du stéphanien de blanzy-montceau (massif central français). stratigraphie et paléoécologie. revue périodique de ‚la physiophyle‘, societé d‘ études des sciences naturelles et historiques de montceau-les-mines, 100 (supplément), 1–270. laveine, j.-p.(1967): contribution a l‘étude de la flore du terrain houiller. les neuroptéridées du nord de la france.– études géologiques pour l‘atlas topographie souterraine, 1/5, 1–344, pls a–p, 1–84. laveine, j.-p., belhis, a., lemoigne, y. & zhang, s. (1992): frond architecture in the genera neuralethopteris cremer, alethopteris sternberg and lonchopteris brongniart (carboniferous pteridosperms).– revue de paléobiologie, volume spécial, geneva, 6, 149–166. seward, a.c. (1917): fossil plants. volume iii. pteridospemae, cycadofilices, cordaitales, cycadophyta.– hafner publishing company, new york & london (reprint 1963), 656 p. šimůnek, z. (1999): cuticles of neuropteris auriculata (brongniart) potonié from the stephanian b of the czech republic. acta universitatis carolinae.– geologica, 43, 4, 625–631. šimůnek, z. (2015): cuticles of the polish type material of cordaites palmaeformis (göppert)weiss and a cordaites principalis-like form from germany, pennsylvanian.– review of palaeobotany and palynology, 223, 50–70. stur, d. (1877): die culm-flora der ostrauer und waldenburger schichten.– abhandlungen der kaiserlich-königlichen geologischen reichsanstalt, 8/2, 107–472. tenchov, y. & cleal, c.j. (2010): neuralethopteris foliage (medullosales) in the carboniferous of the dobrudzha coalfield, bulgaria.– review of palaeobotany and palynology, 158, 298–307. doi: 10.1016/j.revpalbo.2009.10.001 g eologia c roatica zbyněk šimůnek: cuticular characteristics of neuralethopteris jongmansii laveine (medullosalean foliage, westphalian, intrasudetic basin, poland) 7 g eo lo gi a c ro at ic a geologia croatica 70/18 plate 3 neuralethopteris jongmansii laveine. loc. wałbrzych, „langsettian“, coll. göppert, wrocław univ., inv. no. 1667 p. abaxial cuticles and cuticles in sem. a – abaxial cuticle with costal and intercostal fields; intercostal fields with stomata and small papillae on epidermal cells. slide 603/6. b – close up of three stomata from fig. b. note the papillae on the subsidiary cells and normal epidermal cells. c – abaxial cuticle with stomata. slide 456/3 d – close up of abaxial cuticle with stomata and papillae on epidermal cells from fig. c. e – close up of a stoma from fig. d. note the papillae on the subsidiary cells. f – cuticle under sem. stomata are not discernible. sem stub 39. g – abaxial cuticle in sem. sem stub 84. h – close up of abaxial cuticle from fig. g. g eologia c roatica zbyněk šimůnek: cuticular characteristics of neuralethopteris jongmansii laveine (medullosalean foliage, westphalian, intrasudetic basin, poland) 9 g eo lo gi a c ro at ic a geologia croatica 70/110 plate 4 neuralethopteris jongmansii laveine. loc. wałbrzych, „langsetian“, coll. göppert, wrocław univ., inv. no. 1667 p. cuticles under sem. a – cuticle in inner view with discernible anticlinal walls. sem stub 84. b – detail of fig a., with discernible anticlinal cell walls and small papilla-like projections on the corners of cells. c – cuticular fragment from the inner side with clearly discernible cells (lighter) and a stoma (s) on the cuticle in background in the upper right corner. sem stub 84. d – detail of the stoma from fig. c. note the papillae (p). 2016 | 69/2 | 195–200 | 2 figs. | 1 pl. | www.geologia-croatica journal of the croatian geological survey and the croatian geological society 1. introduction the scaphopoda is a class of mollusca, also known as the “tusk shells”. their shell is tubular and generally curved, having open­ ings at both ends. scaphopods are a cosmopolitan marine infau­ nal species, and live from the intertidal zones down to depths of more than 6000 m. scaphopod species mostly burrow in sand or mud, with their head pointed downwards, and the narrow poste­ rior end of the shell protruding above the substratum (knud­ sen, 1964; lamprell & healy, 1998 and references therein; habdija et al., 2011). although the scaphopod systematics have been revised over a few decades, the time of their appearance is still a matter of debate, as are their phylogenetics, so they are considered to be a puzzling molluscan class. two orders of scaphopods are known: dentaliida and gadilida, which differ both morphologi­ cally, in shell and foot form, and behaviourally, in different bur­ rowing activities (lamprell & healy, 1998 and references therein; steiner & kabat, 2001, 2004). this paper focuses on the badenian dentaliid species fissi­ dentalium badense (partsch in hörnes), recorded in the mio cene deposits of the paratethys, and widely distributed in ba­ denian sediments of the central paratethys (e.g. baldi, 1960; kojumdgieva & strachimirov, 1960; balluk, 1972; tita, 2007; harzhauser et al., 2011). specimens of f. ba­ dense included here were collected from the badenian sediments of the south and southwestern margin of the central paratethys (croatia, bosnia and herzegovina and serbia). the analyzed spe­ cimens are housed at the natural history museum belgrade (nhmb) and croatian natural history museum (cnhm). the first finding of f. badense from bosnia and herzegovina is pub­ lished here. 2. geological setting the central paratethys extended from bavaria to the carpathian mountain chain (e.g. rögl 1998, 1999). badenian sediments fissidentalium badense (partsch in hörnes, 1856) from the badenian deposits of the south and southwestern margin of the pannonian basin system (central paratethys) gordana jovanović1 and marija bošnjak2 1 natural history museum belgrade, department of paleontology, division of geology, njegoševa 51, belgrade, serbia; (gordana.j@nhmbeo.rs) 2 croatian natural history museum, department of geology and paleontology, demetrova 1, zagreb, croatia; (corresponding author: marija.bosnjak@hpm.hr) doi: 10.4154/gc.2016.20 abstract the badenian (middle miocene) scaphopoda from the south and southwestern margin of the pannonian basin system (central paratethys) are poorly documented, and in published papers mostly presented by short lists of identified species. for the present study, 300 scaphopod specimens were examined with the focus on a singular species, fissidentalium badense (partsch in hörnes, 1856). this species is represented by 152 specimens housed in the natural history museum belgrade and the croatian natural history museum in zagreb. the most numerous and the best preserved specimens of f. badense were collected at the višnjica locality near belgrade (serbia), while the others originate from the vicinity of zagreb (croatia) and ugljevik (bosnia and herzegovina). from the investigated area belong palaeogeographically to the south and southwestern margin of the central paratethys, and geotectonically to the pannonian basin system, surrounded by the alps, carpathians and dinarides (fig. 1) (e.g. rögl 1998, 1999; pavelić, 2001, 2002; piller et al., 2007). the beginning of the badenian epoch is marked by a marine transgression, which flooded the areas behind the newly uplifted mountain chains (paratethys) and was also prominent in the medi­ terranean (fig. 1) (rögl, 1998, 1999; kováč et al., 2007). ac­ cording to numerous papers, the badenian deposits of the south and southwestern margin of the central paratethys lie discorda­ ntly on the older miocene, mesozoic or even palaeozoic deposits. the contact with basal rocks is in many places unclear or erosive or tectonic in character (e.g. šikić et al., 1978, 1979; basch, 1983a, b; vrabac & mihajlović, 1990; anđel ković et al., 1991; pavelić, 2001, 2002; savić et al., 2005; pikija, 2009). at the southern margin of central paratethys, f. badense is recorded in the lower badenian deposits of serbia (wider bel­ grade region) (petković et al., 1976), in the assumed lower to middle badenian of western serbia (žujović, 1889; pavlović, 1903; stevanović, 1949; petrović, 1967), and in the lower badenian (upper lagenidae zone) in northeastern bosnia and herzegovina (bogutovo selo) (vrabac et al., 2013, 2014; pe­ zelj et al., 2013) (fig. 1). in the area of the southwestern margin of the central paratethys, this species is present in the miocene (probably lower badenian) marls of the wider zagreb region (med vednica mt., čučerje area) (kochansky, 1944, 1957; ćorić et al., 2009), and in the assumed middle to upper bade­ nian deposits of the samobor area (vrhovčak locality, previously known as „zaprešić breg“ or „zaprešić brijeg“) (šuklje, 1929; pavlovsky, 1957, 1960; bajraktarević, 1978; vrsalj ko, 2003; bakrač et al., 2010). in the badenian sediments of the glinsko pokuplje area, this species is found at one locality (pi­ lar, 1873). article history: manuscript received december 16, 2015 revised manuscript accepted may 31, 2016 available online june 28, 2016 keywords: fissidentalium badense, badenian, pannonian basin system, central paratethys g eo lo gi a c ro at ic a geologia croatica 69/2196 3. materials and methods three hundred scaphopod shells were examined, and 152 of them belong to the species fissidentalium badense (partsch in hörnes). all the analyzed specimens are damaged, mostly in the apex area, and the majority of specimens are preserved as shell fragments. nhmb specimens were collected at the višnjica locality (wider area of belgrade), and they are a part of the p. pavlović collection, assembled in 1897 (90 specimens) and the p. ste va­ nović collection, assembled in 1962 (40 specimens). other spec­ imens come from the loznica area in western serbia (3 speci­ mens), and bogutovo selo near ugljevik, bosnia and herzegovina (1 specimen). cnhm specimens originating from the wider zagreb region are part of the „marine miocene fauna of the southern part of the medvednica mt.“ collection (10 specimens) and the „miocene fauna of zaprešić breg near samobor“ collection (5 specimens). specimens from the third locality are part of the „miocene and pliocene fauna from the glinsko pokuplje area and zrinjsko­ dvorska valley“ collection (3 specimens). the site yielding the largest number of scaphopods is višnjica (fig. 1), with 280 specimens from clayey sediments, 130 among them belonging to f. badense (luković, 1922; jova­ nović & jovanović, 1998). this fossil fauna is the best pre­ served, and therefore chosen to be described here. determination of species is based upon several papers (e.g. hörnes, 1856; sacco, 1897; kojumdgieva & stra­ chimirov, 1960; pavia, 1991; steiner & kabat 2001, 2004). parameters used in the determination are after steiner (1999) and silva­filho et al. (2012) (fig. 2). 4. results systematic part class scaphopoda bronn, 1862 order dentaliida da costa, 1776 family dentaliidae children, 1834 genus fissidentalium fischer, 1885 subgenus antalis adams & adams, 1854 fissidentalium badense (partsch in hörnes, 1856) (pl. 1, figs. 1­6) type species: dentalium ergasticim fischer, 1885, monotype 1856 dentalium badense – hörnes, p. 652, pl. 50, fig. 30 1897 entalis badensis (partsch) et var. – sacco, p. 107–108, pl. 9, figs. 17–30 1925 dentalium (entalis) badense partsch var. borealis kautsky – kautsky, p. 53–54, pl. 5, fig. 12 1929 dentalium badense (partsch) – šuklje, p. 52 1947 dentalium (fissidentalium) badense partsch – tau­ ber, p. 302, pl. 7, figs. 8–10, pl. 8, fig. 3 1897 entalis badensis – sacco, p.107, pl. 9, figs. 17–20 1960 dentalium (entalis) badensis partsch in hörnes – kojumdgieva & strachimirov, p. 225, pl. 52, figs. 19–20 1960 dentalium badense partsch – baldi, p. 57, pl. 1, fig. 5 1991 fissidentalium badense (partsch in hörnes, 1856) – pavia, p. 146, pl. 5, fig. 4; pl. 6, fig. 6. (cum syn.). 1998 dentalium badense partschi – jovanović & jovanović, p. 201–202 2011 fissidentalium badense (partsch in hörnes, 1856) – harzhauser et al., p. 219, pl. 8. figs. 6–7 2013 dentalium (antalis) badense (partsch, 1856) – rout­ nerová, p. 20, pl. 2, fig. 2 material: 20 relatively well preserved and 110 damaged spe­ cimens from the višnjica locality, 3 specimens from the loznica area (serbia), 10 damaged specimens from the medvednica mt. (čučerje area), 5 specimens from the „zaprešić breg“ locality and 3 specimens from the glinsko pokuplje area (croatia), 1 specimen from bogutovo selo near ugljevik (bosnia and herzego vina). dimensions: l = 37.3 mm; larc = 32.0 mm; ha = 6.4 mm; wa = 6.3 mm; hp = 2.9 mm; wp = 2.8 mm. description: shell is medium to large, solid, moderately curv ed, narrow and elongated, open at both ends. dorsal side is concave, and the ventral is convex. the apex is damaged in all the collected specimens. the shell narrows and slightly curves to the wider anterior opening. the shell is ornamented with solid radial ribs and growth lines. sharp and moderately high, 8 to 10 radial ribs are near the apical area. ribs become lower and almost flat near the wider end of the shell. secondary ribs are inserted figure 1. geographic and paleogeographic setting of the investigated area with marked localities containing recorded dentaliids (after kováč et al., 2007). figure 2. morphometric measurement parameters: l − length, max – maximum diameter, dmax – maximum distance from the anterior opening, arc – curvature maximum, larc − maximum length from the apex to the deepest point of the curvature, ha − height of the ventral opening, wa − width of the ventral opening, hp − apical height, wp − apical width (after steiner, 1999; silva-filho et al., 2012). g eologia c roatica gordana jovanović and marija bošnjak: fissidentalium badense (partsch in hörnes, 1856) from the badenian deposits of ... 197 plate 1. fissidentalium badense (partsch in hörnes, 1856). 1 višnjica locality, serbia (inv. no. k−2347/1); 2 loznica, serbia (inv. no. k−2689); 3 bogutovo selo, bosnia and herzegovina (inv. no. k−6746); 4 čučerje, croatia (inv. no. 573); 5 vrhovčak („zaprešić breg“), croatia (inv. no. 1.413); 6 glinsko pokuplje area, croatia (inv. no. 1.220). g eo lo gi a c ro at ic a geologia croatica 69/2198 between the primary ribs at various distances from the apex. the maximum number of inserted ribs near the posterior part of the shell does not exceed 30. the primary and secondary ribs at the posterior side of the shell are almost indistinguishable from each other with only minor differences. the species varies in number and thickness of the secondary ribs. concave interrib spaces vary in width. together with the radial ribs, fine and dense irregular growth lines (except in the apical area) characterize the shell sur­ face. the cross­section of both ends is subcircular. remarks: many authors studied the phylogeny and classifica­ tion of the scaphopods (e.g. reynolds, 1997; reynolds & akoko, 1999). fissidentalium badense (partsch in hörnes, 1856) was first recognized as dentalium badense (hörnes, 1856), entalis (sacco, 1897) or dentalium (entalis) badensis (kojum­ dgieva & strachimirov, 1960). f. badense from the višnjica locality, and presented here, fits the descriptions by pavia (1991). the species described in kojumdgieva & strachimirov (1960) has more secondary ribs (35), as do several specimens from koritnica, poland (balluk, 1972). steiner & kabat (2004) single out the subgenus dentalium linnaeus 1758. in the re­ search of the taxonomy and ecology of the recent genus fissiden­ talium (fischer), lamprell & healy (1998) indicate the significance of the aperture, and the number and rib morphology that can contribute to the research of the fossil species. geographic and stratigraphic distribution: fissidenta­ lium badense (partsch in hörnes, 1856) appears during the burdigalian in the mediterranean at the torino hills (sacco, 1897), and in the lower miocene of the paratethys (harzhauser, 2002; harzhauser et al., 2011). f. badense has a wide geogra­ phic distribution, and represents a species typical of the middle miocene of the paratethys (e.g. kojumdgieva & strachi­ mirov, 1960; pavia, 1991; harzhauser et al., 2011). 5. discussion in the badenian sediments of the south and southwestern margin of the central paratethys, the majority of scaphopod discoveries belong to the dentaliids. here, we analyzed and revised fissiden­ talium badense (partsch in hörnes, 1856) specimens stored at the nhmb and cnhm. given the number of the recorded dentaliids, višnjica near belgrade (serbia) is the site yielding the largest number of specimens. at the višnjica locality, scaphopods were discovered in the clayey sediments, known as the „višnjica clays“ or the „clays with pleurothoma“. this site was compared to the badenian stratotype baden­sooss in vienna (pavlović, 1903; luković, 1922), which contains many specimens of f. badense. the stratigraphic position of the „višnjica clays“ is not precisely determined. based upon foraminifera, stevanović (1977) attributes it to the mid­ dle badenian, and grujičić (2010) specifies the zone with spi­ ro rutilus carinatus (d’orbigny). sandstones containing rare fine­shelled pectens (costelamussium sp.), aequipecten macrotis (sowerby) and aequipecten scabrella (lamarck) (luko­ vić, 1922) cover the clay stratum. these pectinid species also occur in the lower badenian of bukovac on the fruška gora mt. (jovanović, 2014), in the grund gaindorf formation in aus­ tria (mandic & harzhauser, 2003; mandic, 2004), and in the lower badenian (lagenidae zone) sediments of szokoly, hungary (baldi, 1960). the „višnjica clays“ contain numerous scaphopod specimens: fissidentalium badense (partsch in hörnes), gadilina jani hörnes, dentalium sexangulum gmelin, dentalium (antale) novemcostatum decemcostulata sacco, dentalium (dentalium) michelottii hörnes and fis­ sidentalium mutabile (doderlein). in the lower badenian argillaceous marls of the wider bel­ grade region, deep sea molluscs are very common: neopycnodonte cochlear poli, lentipecten corneus denudatus (reuss), vaginella austriaca kittl and aturia aturi (basterot) (pet ković et al., 1976; jovanović, 2014). these findings, as well as the record of parvamussium duodecimlamellatum (bronn), indicate a lower badenian age (studencka et al., 1998; selmeczi et al., 2012; jovanović, 2014). in the miocene (probably lower badenian) marls of the wider zagreb region („čučerje“ develop­ ment on the medvednica mt.), the wider belgrade region and ug­ ljevik (bogutovo selo), together with dentaliids, scaphopods are accompanied by a pelagic fauna of nautilids (aturia aturi (bas­ terot), pteropods (vaginella austriaca kittl) and planktonic foraminifers (kochansky, 1944; stevanović, 1977, ava­ nić et al., 1995; jovanović, 2014). these known data, together with further detailed dentaliid analysis, can contribute to the re­ construction of the first middle miocene marine transgression in the south and southwestern margin of the central paratethys. all the published data and records suggest that f. badense mostly lived in muddy and muddy­sandy substrate at all the stud­ ied localities in serbia, bosnia and herzegovina and croatia. this species was widespread during the lower badenian, with fossil evidence from the clayey sediments of austria (baden­sooss) (rögl et al., 2009), romania (lăpugiu de sus) (tita, 2007), slovakia (balluk, 1972; harzhauser et al., 2011), hungary (baldi, 1960) and bulgaria (kojumdgieva & strachimi­ rov, 1960). the distribution of f. badense indicates the contem­ porary marine connections and migration routes. due to the re­ corded and afore­mentioned findings, possible migration routes of f. badense to the area of paratethys could be the southwestern („transtethyan corridor“) and the northern marine passages (e.g. rögl, 1998; studencka et al., 1998; kováč et al., 2007). 6. conclusions this paper presents the scaphopod species fissidentalium ba dense (partsch in hörnes, 1856) housed at the natural history museum belgrade and the croatian natural history museum. fossil material was collected from the badenian (middle mio­ cene) deposits of the south and southwestern margin of the cen­ tral paratethys. the age of the analyzed specimens from serbia and bosnia and herzegovina stored at the natural history museum belgrade is the lower badenian, while other middle miocene findings are questionable in age and require further research. during the upper part of the lower badenian, the species had a wide geographic distribution, which implys an open marine connection of the central paratethys with other marine areas. according to the available fossil record, fissidentalium badense lived on a muddy to muddy­sandy substrate. acknowledgment the authors thank prof. sejfudin vrabac (faculty of mining, geology and civil engineering, university of tuzla, bosnia and herzegovina), prof. jasenka sremac (faculty of science, uni­ versity of zagreb, croatia), dr. davor vrsaljko (croatian na­ tural history museum, zagreb) and anonymous reviewers for useful comments which helped us to improve the paper, and to dr. davorka radovčić (croatian natural history museum, zagreb) for help in translating the manuscript. g eologia c roatica gordana jovanović and marija bošnjak: fissidentalium badense (partsch in hörnes, 1856) from the badenian deposits of ... 199 references anđelković, m., eremija, m., pavlović, m., anđelković, j. & mi tro­ vić­petrović, j. (1991): badenski vek.– in: anđelković, m. (ed.): paleo­ geografija srbije, tercijar. univerzitet u beogradu, rudarsko­geološki fakultet, institut za regionalnu geologiju i paleontologiju beograd, 134–159. avanić, r., pavelić, d., brkić, m., miknić, m. & šimunić, a. (1995): lapori i biokalkareniti vejalnice.− in: šikić, k. (ed.): geološki vodič medvednice. in­ stitut za geološka istraživanja ina­industrija nafte, d.d., zagreb, 159–164. bajraktarević, z. (1978): gornjotortonska starost sedimenata zaprešić­brijega kod samobora [upper tortonian sediments of zaprešić-brijeg near samobor, north croatia – in croatian and english].– geol. vjesnik, 30/1, 63–69. bakrač, k., hajek­tadesse, v., miknić, m., grizelj, a., hećimović, i. & kovačić, m. (2010): evidence for badenian local sea level changes in the proxi mal area of the north croatian basin.– geologia croatica, 63/3, 259–269. doi: 10.4154/gc.2010.21 baldi, t. (1960): tortonische molluskenfauna von „badener tegel­fazies” aus szo­ kolya, nordungarn.– annales historico­naturales musei nationalis hungarici, 52, 51–99. balluk, w. (1972): lower tortonian scaphopods from the korgtnica clays, southern slopes of the holy cross mts.– acta geologica polonica, 22/3, 545–583. basch, o. (1983a): osnovna geološka karta sfrj 1:100000. tumač za list ivanić­grad l 33–81 [basic geological map of sfry 1:100000, geology of the ivanić-grad sheet – in croatian].– geološki zavod, zagreb (1980), savezni geološki zavod, beograd, 81 p. basch, o. (1983b): osnovna geološka karta sfrj 1:100000. list ivanić­grad l 33–81 [basic geological map of sfry 1:100000, geology of the ivanić-grad sheet].– geološki zavod, zagreb (1980), savezni geološki zavod, beograd. ćorić, s., pavelić, d., rögl, f., mandic, o., vrabac, s., avanić, r., jer­ ko vić, l. & vranjković, a. (2009): revised middle miocene datum for initial marine flooding of north croatian basins (pannonian basin system, central paratethys).− geologia croatica, 62/1, 31−43. doi: 10.4154/gc.2009.03 grujičić, lj. (2010): foraminifers of the genus frondicularia from belgrade area danubian meander.− in: banjac, n., maran, a., savić, lj., cukavac, m. & ganić, m. (eds.): proceedings of the 15th congress of geologists of serbia with international participation, belgrade, may 26−29 2010, serbian geological society, 69−72. habdija, i., primc­habdija, b., radanović, i., špoljar, m., matonič­ kin kepčija, r., vujčić karlo, s., miliša, m., ostojić, a. & sertić perić, m. (2011): protista−protozoa i metazoa−invertebrata: strukture i funkci­ je.− alfa d.d., zagreb, 584 p. harzhauser, m. (2002): scaphopoda aus dem karpatium (untermiözan) des kor­ neuburger beckens (niederösterreich).– beitr. paläont., 27, 205–213. harzhauser, m., mandic, o. & schlögl, j. (2011): a late burdigalian bathyal mollusc fauna from the vienna basin (slovakia).– geologica carpathica, 62/3, 211−231. doi: 10.2478/v10096­011­0018­7 hörnes, m. (1856): die fossilen mollusken des tertiär–beckens von wien. i. univalven.– abh. k. k. geol. reichsanstalt, 3, 733 p. jovanović, g. & jovanović, j. (1998): tertiary scaphopods in natural history museum belgrade.− bulletin of the natural history museum, a, 47−50, 199−204. jovanović, g. (2014): badenske školjke jugoistočnog oboda panonskog basena (cen­ tralni paratetis) [badenian bivalves of the southeastern fringe of pannonian basin (central paratethys) – in serbian].– unpubl. phd thesis, faculty of mining and geology, university of belgrade, 252 p. kautsky, f. (1925): das miocän von hemmoor und basbeck­osten.− abhandl. preuss. geol. landesanst. (nf), 97, 1−225. knudsen, j. (1964): scaphopoda and gastropoda from depths exceeding 6000 m.– galathea reports, 7, 125–136. kochansky, v. (1944): fauna marinskog miocena južnog pobočja medvednice (za­ grebačke gore) [miozäne marine fauna des südlichen abhanges der medvednica – zagreber gebirge – in croatian and german].– vjestnik hrv. drž. geol. zav. i hrv. drž. geol. muz., 2–3, 171–280. kochansky­devidé, v. (1957): o fauni marinskog miocena i o tortonskom „šliru” medvednice (zagrebačka gora) [ueber die fauna des marinen miozäns und über den tortonischen ″schlier″ von medvednica (zagreber gebirge) – in croatian and german].– geol. vjesnik, 10 (1956), 39–50. kojumdgieva, e. & strachimirov, b. (1960): le tortonien du type viennois (in bulgarian with french summary).− in: kojumdgieva, e. & strachimi­ rov, b. (eds.): les fossilles de bulgarie, vii, tortonien.– académie des sciences de bulgarie, sofia, 246 p. kováč, m., andreyeva­grigorovich, a., bajraktarević, z., brzo­ bohatý, r., filipescu, s., fodor, l., harzhauser, m., nagyma­ rosy, a., oszczypko, n., pavelić, d., rögl, f., saftić, b., sliva, ľ. & studencka, b. (2007): badenian evolution of the central paratethys sea: paleogeography, climate and eustatic sea­level changes.– geologica carpathica, 58, 6, 579−606. lamprell, k.l. & healy, j.m. (1998): a revision of the scaphopoda from australian waters (mollusca).− records of the australian museum, supplement 24, 1−189. luković, m. (1922): facije drugog mediteranskog kata u okolini beograda.– geološki anali balkanskoga poluostrva, 7/1, 22–41. mandic, o. (2004): pectinid bivalves from the grund formation (lower badenian, middle miocene, alpine­carpathian foredeep) – taxonomic revision and strati­ graphic significance.− geologica carpathica, 55, 129−146. mandic, o. & harzhauser, m. (2003): molluscs from the badenian (middle mi­ ocene) of the gaindorf formation (alpine molasse basin, ne austria) − taxono­ my, paleoecology and biostratigraphy.− annalen des naturhistorischen museums in wien, 104 a, 85−12. pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bo­ snian sector of the miocene pannonian basin system.– basin research, 12, 359– 376. doi: 10.1046/j.0950­091x.2001.00155.x pavelić, d. (2002): the south­western boundary of central paratethys.– geologica croatica, 55/1, 83–92. pavia, g. (1991): i molluschi del messiniano di borelli (torino). 2. scaphopoda.– boll. mus. reg. sci. nat. torino, 9/1, 105–172. pavlović, p. (1903): prinove geološkog zavoda velike škole.− geološki anali bal­ kanskoga poluostrva, 6, 294−325. pavlovsky, m. (1957): prilog poznavanju miocenskih gastropoda zaprešić­brijega kraj samobora [ein beitrag zur kenntnis miozäner gastropoden von zaprešićbrijeg bei samobor – in croatian and german].– geol. vjesnik, 10, 51–55. pavlovsky, m. (1960): novi elementi faune zaprešić­brijega kraj samobora [neue elemente der fauna von zaprešić­brijeg bei samobor – in croatian and german].– geol. vjesnik, 13, 213–216. petković, k., čičulić­trifunović, m., pašić, m. & rakić, m. (1976): fruš­ ka gora – monografski prikaz geološke građe i tektonskog sklopa.– matica srpska. odeljenje za prirodne nauke novi sad, 277 p. petrović, m. (1967): prilog poznavanju tortonskih foraminifera iz beograda i bliže okoline.– geološki anali balkanskoga poluostrva, 29, 27–38. pezelj, đ., mandic, o. & ćorić, s. (2013): paleoenvironmental dynamics in the southern pannonian basin during initial middle miocene marine flooding.– geologica carpathica, 64/1, 81–100. pikija, m. (2009): litavac i klastične naslage s vulkanitima (baden – m4).− in: velić, i. & vlahović, i. (eds.): tumač geološke karte republike hrvatske 1:300.000 [geological map of the republic of croatia].– hrvatski geološki institut, zagreb, 86−87. pilar, gj. (1873): trećegorje i podloga mu u glinskom pokuplju.− rad jugosl. akad. znan. umjet., 25, 53–179. piller, w.e., harzhauser, m. & mandic, o. (2007): miocene central paratet­ hys stratigraphy – current status and future directions.– stratigraphy, 4, 2/3, 151– 168. reynolds, p. (1997): the phylogeny and classification of scaphopoda (mollusca): an assessment of curent resolution and cladistic reanalysis.− zoologica scripta, 26/1, doi: 13−21. 10.1111/j.1463­6409.1997.tb00406.x reynolds, p. & akiko, o. (1999): phylogenetic relationships among families of the scaphopoda (mollusca).− zoological journal of the linnean society, 126, 131−154. doi: 10.1111/j.1096­3642.1999.tb00151.x rögl, f. (1998): palaeogeographic considerations for mediterranean and paratethys seaways (oligocene to miocene).– annalen des naturhistorischen museums in wien, 99 a, 279–310, wien. rögl, f. (1999): mediterranean and paratethys. facts and hypotheses of an oligocene to miocene paleogeography (short overview).– geologica carpathica, 50/4, 339–349. rögl, f., ćorić, s., harzhauser, m., jimenez­moreno, g., kroh, a., schultz, o., wessely, g. & zorn, i. (2009): biostratigraphy of the middle miocene stratotype at baden­sooss (lower austria).– in: filipescu, f. (ed.): 3rd international workshop: neogene of central and south­eastern europe cluj­na­ poca, may 20­24, abstract volume, 87–88. routnerová, k. (2013): nové nálezy badenských měkkýšů z lokality lapugiu de sus (rumunsko) [new finds of badenian molluscs from lapugiu de sus (romania) – in romanian, with an english abstract].– unpubl. thesis, faculty of science, masaryk university, 30 p. sacco (1897): i molluschi dei terreni terziarii del piemonte e della liguria. parte xxii, torino, 148 p. savić, lj., krstić, n., trofimović, n., ječmenica, z. & jovanović, g. (2005): badenske lagune ugljevika [badenian lagoons of ugljevik – in serbian, with an english summary].– zapisnici srpskog geološkog društva za 1998–2003, 25–33. selmeczi, i., lantos m., bohn­havas, m., nagymarosy, a. & szegő, e. (2012): correlation of bio­ and magnetostratigraphy of badenian sequences from western and northern hungary.− geologica carpathica, 63/3, 219−232. doi: 10.2478/v10096­012­0019­1 g eo lo gi a c ro at ic a geologia croatica 69/2200 silva­filho, g.f.s., tenório, d.o., pinto, s.l. & alves, m.s. (2012): mollus­ ca scaphopoda bronn, 1862 da costa nordeste do brasil.− tropical oceanograp­ hy, 40/1, 29−103. steiner, g. (1999): a new genus and species of the family annulidentaliidae (scapho­ poda: dentalida) and its systematic implications.− journal of molluscan studies, 65/2, 151−161. steiner, g. & kabat, a.r. (2001): catalog of superspecific taxa of scaphopoda (mollusca).− zoosystema, 23/3, 433−460. steiner, g. & kabat, a.r. (2004): catalog of species­group names of recent and fossil scaphopoda (mollusca).− zoosystema, 26/4, 549−726. stevanović, p. (1949): prilozi za stratigrafiju miocenskih naslaga u basenu korenite – jadra (podrinje).– glasnik prirodnjačkog muzeja u beogradu, 9, 1–50. stevanović, p. (1977): miocen okoline beograda.– in: petković, k. (ed.): geologija srbije (stratigrafija kenozoika) 2 (3). zavod regionalnu geologiju i paleontologiju rudarsko­geološkog fakulteta univerziteta u beogradu, beograd, 107–145. studencka, b., gontsharova, i. a. & popov, s.v. (1998): the bivalve faunas as a basis for reconstruction of the middle miocene history of the paratethys.– ac­ ta geologica polonica, 48/3, 285–342. šikić, k., basch, o. & šimunić, a. (1978): osnovna geološka karta sfrj 1:100000, list zagreb l33–80 [basic geological map of sfry 1:100000, zagreb sheet – in croatian].– institut za geološka istraživanja zagreb (1972), savezni geološki za­ vod, beograd. šikić, k., basch, o. & šimunić, a. (1979): osnovna geološka karta sfrj 1:100000. tumač za list zagreb l33–80 [basic geological map of sfry 1:100000, geology of the zagreb sheet – in croatian].– institut za geološka istraživanja zagreb (1972), savezni geološki zavod, beograd, 81 p. šuklje, f. (1929): mediteranska fauna zaprešić­brijega u samoborskoj gori [medi­ terranean fauna in zaprešić brijeg location in the samoborska gora mt. – in cro­ atian].– vijesti geološkog zavoda, 3, 1–52. tauber. a. f. (1947): lebensspuren von krebsen an fossllen scaphopodenschalen.– in: papp, a., zapfe, h., bachmayer, f. & tauber, a.f.: lebensspuren mariner krebse. s. b. akad. wiss. wien, abt. 1, bd. 155. tita, r. (2007): comments on the badenian fauna (middle miocene) from bahna (southern carpathians, romania).– travaux du museum national d’histoire naturelle grigore antipa, 50, 543–554. vrabac, s. & mihajlović, đ. (1990): paleontološko­biostratigrafske odlike i od­ nos badena i sarmata na površinskom kopu bogutovo selo kod ugljevika (si bo­ sna) [paleontological­biostratigraphical character and relationship of badenian and sarmatian at open­pit mine bogutovo selo near ugljevik (ne bosnia) – in bos nian/serbian/croatian].– xii kongres geologa jugoslavije, ohrid, knj. i, 312–328. vrabac, s., ćorić, s., đulović, i. & ječmenica, z. (2013): biostratigrafske zone donjeg badena u profilu bušotine ui – 568/3 kod ugljevika.– in: babajić, e., đurić, n., hrvatović, h. & skopljak, f. (eds.): zbornik radova v savjetovanja geologa bosne i hercegovine sa međunarodnim učešćem, pale, 136–145. vrabac, s., đulović, i. & ječmenica, z. (2014): baden i sarmat u profilu kr –5 kod ugljevika.– glasnik rudarsko­geološko­građevinskog fakulteta, 2, 39–50. vrsaljko, d. (2003): biostratigrafija miocenskih naslaga žumberačkog i samobor­ skog gorja na temelju mekušaca [biostratigraphy of the miocene deposits from the žumberak mt. and samoborsko gorje mts. on the basis of molluscs – in croatian, with an english abstract].– unpubl. phd thesis, university of zagreb, 143 p. žujović, j. (1889): osnovi za geologiju kraljevine srbije sa skicom geološke gradje.– geološki anali balkanskoga poluostrva, 1, 1–130. 12-dolenec.indd 143 � ab stra ct stable nitrogen isotope ratios of particulate matter pom, zooplankton and selected biota such as mytilus galloprovincialis were used to assess the impact of anthropogenically derived organic matter from untreated domestic sewage, municipal and industrial effl uents on the coastal ecosystem of kosirina bay (murter island). the differences in δ15n values observed in pom and organisms collected in kosirina bay were compared to pom and biota sampled at unaffected sites from the southern part of kornati island and highly impacted pirovac bay. this revealed only very minor effects of anthropogenic inputs of nutrients and organic matter, most probably derived from a sewage outfall south of tužbina island. keywords: particulate organic matter (pom), zooplankton, mytilus galloprovincialis, sewage, kosirina bay, murter island, central adriatic use of stable nitrogen isotope signatures of anthropogenic organic matter in the coastal environment: a case study of the kosirina bay (murter island, croatia) � matej dolenec1, petra žvab1, goran mihelčić3, živana lambaša belak4, sonja lojen2, goran kniewald3, tadej dolenec1,2 and nastja rogan šmuc1 1department of geology, faculty of natural sciences and engineering, aškerčeva 12, 1000 ljubljana, slovenia; (matej.dolenec@ntf.uni-lj.si) 2department of environmental sciences, jožef stefan institute, jamova 39, 1000 ljubljana, slovenia 3centre for marine and environmental research, ruđer bošković institute, bijenička 54, 10 000 zagreb, croatia 4šibenik-knin county, vladimira nazora 1, 22000 šibenik, croatia doi: 104154/gc.2011.12 geologia croatica 64/2 143–152 5 figs. 3 tabs. zagreb 2011 geologia croaticageologia croatica nutrient input to many near shore ecosystems could be attributed to inputs from sewage treatment facilities as well as to untreated domestic sewage and municipal and industrial wastes (nixon et al., 1986; bachtiar et al., 1996; alonso-rodrigez et al., 2000, carmichael et al., 2004; hadwen & arthington, 2007). this increase in nutrient load has resulted in n enrichment of aquatic ecosystems, which could lead to the eutrophication of many coastal ecosystems and consequent deterioration of aquatic communities 1. introduction expanding urbanisation and other anthropogenic activities, such as industry, traffi c, agriculture and tourism in coastal areas have resulted in increased nutrient inputs to coastal eco systems (howarth et al., 2002; dolenec et al., 2006a, pruell et al., 2006; carmichael et al., 2004, valiela & bown, 2002, costanzo et al., 2001; vizzini & mazzola, 2006). the major source of anthropogenic geologia croatica 64/2geologia croatica 144 (howarth, 1998; rabalais, 2002; spies et al., 1989; vizzini & mazzola, 2006; davis & koop, 2006). in recent literature, substantial attention has been paid to evaluating the environmental impact of anthropogenic inputs and organic matter originating from different sewage effl uents (hansson et al., 1997; tucker et al., 1999; risk & erdmann, 2000; heikoop et al., 2000; sigleo & mac ko, 2002; rogers, 2003; costanzo et al., 2003; vizzini & mazzola, 2006; dolenec et al., 2006a; 2007). this leads to increased concentrations of dissolved nutrients and particulate organic matter (pom), and consequent ly to increased primary production in the water column (evgenidou & valiela, 2002 and references therein). the extent and dispersal of anthropogenic inputs is obviously dependent on several factors, such as the quantity and quality of waste, hydrography, hydrodynamic regime and other environmental features of the area affected by the discharge, (e.g. the physical and chemical characteristics of the water column and sediments, depth) (vizzini & mazzola, 2006; sutherland et al., 2001; alongi et al., 2003; kress et al., 2004). the pom derived from sewage effl uents has typically higher δ15n values relative to pom of unaffected marine environments, due to the alteration of δ15n of dissolved n pool by anthropogenically-derived n wastes with typically high δ15n values (fogg et al., 1998), and processes that may alter the isotope composition of the dissolved n-pool, such as nitrifi cation, denitrifi cation, n-fi xation, etc. (kendall, 1998); δ15n of pom can therefore be used to trace the impact areas of anthropogenically derived nitrogen inputs (costanzo et al., 2001; gaston et al., 2004; dolenec et al., 2006a; 2007). previous studies have shown that sewage effl uents signifi cantly affect the nitrogen isotope composition of all n pools; dissolved inorganic and organic nitrogen, microbial po pulations (costanzo et al., 2000; dolenec et al., 2006a) and macrofauna (dolenec et al., 2007, risk & erdman, 2000; dolenec et al., 2005; 2006a,b; 2007). the present study investigates the impact of anthropogenically derived sewage effl uents and their possible transport patterns in the semi-enclosed pirovac bay and the coa stal part of the murter sea (central adriatic, croatia). ex pansion of the human population during the tourist season not serviced by adequate municipal infrastructure also represents an additional load of sewage waste on marine coastal ecosystems of murter island. tourist regions without adequate municipal infrastructure discharge sewage wastes directly into the sea. the aim of the present study was: 1) to identify the possible effects of sewage effl uents on pom and on resident biota in kosirina bay in the western part of murter island; 2) to asses the impact of effl uents on the δ15n of pom and biota in kosirina bay, which may receive sewage effl uents by prevalently current-derived mass transport from the south east where the main pollution sources are located; 3) to create maps of the δ15n values of pom, which would enable determination of the geographic extent of a possible anthropogenic impact in kosirina bay. 2. materials and methods 2.1. study area the study was conducted in kosirina bay (kb-1 to kb-10) on the southwestern coast of murter island (fig. 1). as reference areas, the semi-enclosed pirovac bay (pb-1 to pb-8) and offshore locations south of the kornati islands (roff-1 to roff-4) were also sampled. the maximum water depth in kosirina bay is between 12 and 14 m, and in pirovac bay between 23–26 m. water salinity varies from 28.2 to 36.3 permil in pirovac bay while in kosirina bay and offshore locations salinity is between 36.2 and 38.3 permil. the average water temperature during the sampling period in kosirina bay varied between 20 and 24°c in pirovac bay between 22 and 26°c and at offshore locations between 21 and 25°c. kosirina bay is a typical shallow coastal area potentially affected by predominately current derived anthropogenic nutrients and outfl ow of municipal sewage from the tourist centre of jezera. one of the closest pollution sources is a direct outfall of municipal sewage southeast of tužbina island (soj in fig.1). dominant currents fl ow parallel to the shore. 2.2. sampling particulate organic matter (pom), cons idered as a potential food source for net zooplankton, anemones and mussels, was sampled by vacuum fi ltering 10 to 20 l of seawater collected at 10 locations in kosirina bay (kb-1 to kb-10), as well as at pristine offshore locations south of the kornati islands (roff -1, 2 and 3), and in the anthropogenically most affected semi-enclosed pirovac bay (pb-3, 4, 6, 7 and 8), which receives major inputs of sewage from inadequate domestic septic tank systems, as well as from hotel facilities, autocamps, marinas and small shipyards (fig. 1). to determine the infl uence of sewage outfall on the isotopic composition of pom, three water samples were taken in the vicinity of the discharge. the fi rst outfall is located south of kosirina bay (soj) at a depth of 40 m, the second is near the hrami na marina (som) at a depth of 15 m and the third outfall lies south of the village of betina (sob) also at a depth of 15 m. samples at these three outfall locations were taken at a depth of 5 m directly above the sewage release. water sample at other sampling locations was taken from 1 m below the surface. samples were fi ltered through whatman gf/f glass mi crofi bre fi lter. pom sampling in kosirina bay, pirovac bay and kornati islands was carried out in june, july and august 2006. zooplankton was collected in june 2006 in three different areas: kosirina bay (kb-5), at the offshore locations in the murter sea (roff-1 and between roff-3 and 4) and in pirovac bay (pb-3, 4 and 6) (fig. 1). zooplankton was sampled by towing a net (mesh size: 125 μm) for approximately 30 min. samples of zooplankton were collected in triplicate at two sites within each locality. individual mytilus galloprovincialis were sampled in kosirina bay (kb-4) and at different sites at the offshore locations of the murter sea (roff-1, 2 and 3) and pirovac dolenec et al.: use of stable nitrogen isotope signatures of anthropogenic organic matter in the coastal environment... geologia croatica 145 bay (pb-1, 2, 4, 5, 6, 7 and 8) (fig. 1). to get the strongest possible δ15n signal the sampling period for the biota was limited to the peak of the summer tourist season (the last two weeks in august 2006). primary production is highest in august because of physical parameters including strong light intensity, high temperatures and nutrients. due to intensive tourist activities, the input of untreated human and other sewage effl uents is also maximum during that period. the reference sampling site was selected in the lumbarda reef flat (roff-1) in the open sea which is considered to be unaffected by human activities (fig. 1). biota samples were collected by scuba diving at depths of approximately 2–5 m. mytilus galloprovincialis were group ed according to their shell length into two size categories: small (30 to 50 mm long shells) and large (50 to 80 mm shells) to avoid possible isotope effects caused by ontogenetic dietary shifts (deniro & epstein, 1981; muscatine & kaplan, 1994) and differences in age, which could also affect the nitrogen isotopic composition (owens, 1987). each mussel sample consisted of 5 individuals taken at the same sampling site. upon collection, all the biota sam ples were immediately frozen and kept at –20 ºc till further processing. they were freeze-dried and pulverised using an agate mortar and pestle. dry samples were preserved in desiccators at room temperature until the analyses were carried out. filters of pom were also freeze-dried. 2.3. isotopic analysis isotopic analysis was conducted using a continuous fl owisotope ratio mass spectrometer europa 20–20 with an anca sl preparation module (pdz europa ltd., uk). the results are expressed using standard delta (δ) notation as permil (‰) difference between the sample and reference ratios as follows: δ15n = [rsample / rstandard – 1] × 1000 where r = 15n/14n. laboratory working standards (urea and ammonium sulphate solution) were calibrated against iaea n-1 and iaea n-2 reference materials with δ15n +0.4 and +20.3 ‰, respectively. the standard deviation of a measurement based on multiple analysis of the working standard was generally < 0.15 ‰. 2.4. data analysis statistica 6.0 data analysis software system (statsoft inc) was used for statistical analyses. analysis of variance (one way anova) was performed to test the differences between the pom and mussels collected at three anthropogenically differently impacted areas: 1) reference and other offshore locations (roff sampling sites), figure 1: map of the study area in the kosirina bay (murter island), murter sea, south of the kornati island and in the semi enclosed pirovac bay (central adriatic) showing sites of pom, zooplankton and mytilus galloprovincialis sampling in june, july and august 2006 (soj, som, sob – sewage outfall of jezera – 40 m depth, murter – 15 m depth and betina – 15 m depth). geologia croatica 64/2geologia croatica 146 2) kosirina bay (kb sampling sites) and 3) pirovac bay (pb sampling sites). post-hoc tukey΄s honest (hds) test was used to examine the differences (determined as signifi cant) by anova. for all statistical tests, signifi cance was accepted at p < 0.05. a contour map was constructed by kriging, from δ15n values of particulate organic matter (pom) obtained at each sampling site in the kosirina bay, using the surfer® 8 computer package of golden software. this technique had already been successfully used to obtain shoot density maps of posidonia oceanica, as well as for detecting and mapping sewage impacts in different biota (costanzo et al., 2001; ruiz et al., 2001; dolenec et al., 2005; 2006a,b). 3. results the results of δ15n determination in pom are listed in tab. 1, while tabs. 2 and 3 show the nitrogen isotopic composition of zooplankton and mussels mytilus galloprovincialis. data presented in tab. 2 represent the average nitrogen isotopic composition of bulk zooplankton samples, while those in tab. 3 refer to the δ15n values of an average mussel (mytilus galloprovincialis) sample consisting of 5 individuals (mus cle without digestive gland) taken at the selected sampling sites. the results indicate that the δ15n values of pom, zooplankton and soft tissue of mytilus galloprovincialis were signifi cantly higher at the anthropogenically most affected table 1: δ15n of particulate organic matter (pom) collected in murter sea, kosirina bay, pirovac bay and near sewage outfall (soj, som and sob) in june, july and august 2006 (* reference sampling site). sampling group sampling site δ15n ‰ june july august roff 1 reef flat lumbarda* + 3.0 + 3.2 + 1.8 roff 2 reef flat sedlo + 3.6 + 4.0 + 2.5 roff 3 reef flat čavlin + 3.9 + 4.0 + 2.8 kb 5 kosirina bay kb-1 + 3.6 + 4.3 + 4.8 kb 5 kosirina bay kb-2 + 3.4 + 4.4 + 4.0 kb 5 kosirina bay kb-3 + 3.9 + 6.4 + 4.5 kb 5 kosirina bay kb-4 + 3.4 + 3.7 + 3.3 kb 5 kosirina bay kb-5 + 4.0 + 5.0 + 2.9 kb 5 kosirina bay kb-6 + 4.0 + 5.5 + 3.1 kb 5 kosirina bay kb-7 + 3.2 + 3.6 + 3.9 kb 5 kosirina bay kb-8 – + 3.9 + 4.4 kb 5 kosirina bay kb-9 + 3.6 + 3.6 – kb 5 kosirina bay kb-10 + 3.6 + 4.6 + 4.2 pb 8 pirovac bay i + 6.1 + 7.3 + 8.0 pb 13 port of murter + 6.1 + 7.8 + 7.5 pb 9 reef flat spličak + 6.4 + 8.1 + 8.5 pb 11 sustipanac island + 6.7 + 7.3 + 8.6 pb 12 port of betina + 6.4 + 6.9 + 7.7 soj sewage outfall jezera average: + 6.2 som sewage outfall murter average: + 7.3 sob sewage outfall betina average: + 7.2 table 2: δ15n values of zooplankton collected in the murter sea, kosirina bay and pirovac bay in june 2006. sampling group sampling site δ15n ‰ roff 1 reef flat lumbarda* + 4.3 roff 4 murter sea i + 4.7 roff 4/1 murter sea i + 4.6 kb 5/1 kosirina bay + 4.8 kb 5/2 kosirina bay + 4.6 kb 5/3 kosirina bay + 4.9 pb 8 pirovac bay ii + 7.1 pb 8/1 pirovac bay ii + 7.8 pb 8/2 pirovac bay ii + 7.1 pb 8/3 pirovac bay ii + 7.1 pb 8/4 pirovac bay ii + 7.3 pb 9 reef flat spličak + 7.4 pb 9/1 reef flat spličak + 7.1 pb 9/2 reef flat spličak + 7.4 pb 9/3 reef flat spličak + 7.3 pb 9/4 reef flat spličak + 7.3 pb 10 sustipanac island + 8.0 pb 10/1 sustipanac island + 7.3 dolenec et al.: use of stable nitrogen isotope signatures of anthropogenic organic matter in the coastal environment... geologia croatica 147 sampling sites (pb group) relative to those from the reference site at the reef flat lumbarda (roff-1), as well as at other isolated offshore locations, such as sedlo island (roff-2) and čavlin reef flat (roff-3). δ15n of pom collected in kosirina bay (kb) are, however, only slightly enriched in 15n compared to the unaffected reference and other offshore sampling sites (roff). the pom sampled in pirovac bay (pb) was consistently enriched in 15n compared to the pom from the offshore and kosirina bay locations. it should also be noted that temporal variation during the summer sampling season in δ15n of pom show a general trend toward the more positive values of δ15n from june to august only in pirovac bay (pb group), while the δ15n signal in pom collected in august is less positive than in july in kosirina bay (kb group) and is less positive than in june and july for offshore locations (roff group) (tab. 1, figs. 3 to 5). the distribution pattern of temporal variations during the summer season in δ15n of pom in kosirina bay is presented in fig. 2. enrichment in 15n was observed from june to july while in august the δ15n values were less positive than in july (fig. 2). the highest mean values (8.1 ‰) of δ15n in the pom in pirovac bay (pb) and the lowest mean values (2.4 ‰) in the reference and offshore locations (roff) were observed in august while the largest variations (sd = 0.9) in δ15n of pom values were observed in kosirina bay in july. the average values of δ15n in the pom collected at the sewage outfall soj, som and sob are 6.2, 7.3 and 7.2 ‰. in order to compare the distribution of δ15n values in the pom between periods (june, july and august), the whisker box plot was employed (fig. 3). as shown in fig. 3a the pom group samples collected in june exhibit a statistically signifi cant difference in the mean δ15n values between the roff and pb, as well as between the kb and pb sampling sites, while there was no statistically signifi cant variations between the roff and kb sites. a similar situation was also observed in july (fig. 3b), while in august (fig. 3c), the mean δ15n values of pom collected in the reference and offshore locations and kosirina bay were statistically signifi cantly different from those of the pom from pirovac bay. this was also confi rmed by tuckey’s hsd test. stable nitrogen isotope values for net zooplankton rang ed from +4.3 to +8.0 ‰ with a mean value of +6.45 ‰. too few δ15n values were obtained to make a reliable group-togroup comparison. however, the data undoubtedly indicated that δ15n values of zooplankton collected in pirovac bay were considerably enriched in 15n and statistically signifi cantly different from the δ15n of zooplankton from kosirina bay (kb group), and from reference and other offshore locations (roff group) (fig. 4). this was also suggested by tuckey’s hsd test. stable isotope ratios of mytilus galloprovincialis collected at different sampling sites also varied markedly according to each group in δ15n (tab. 3). the presented data clearly show that the mytilus galloprovincialis from the high ly impacted pirovac bay exhibited δ15n values in the range +6.0 to +8.2 ‰, with a mean value of +7.16 ‰. considerably low er values which varied from +4.1 to +4.2 ‰, with a mean value of +4.13 ‰ were measured in mytilus galloprovincialis from kosirina bay, while the lowest δ15n signal was detected in mussels collected at the reference and other offshore locations. mytilus galloprovincialis from these sampling sites (roff group) had δ15n in the range +3.3 to +3.8 ‰, with a mean value of +3.57 ‰. the analysis of δ15n values measured in mussel tissues during this study for their possible inter group variation showed, according to tuckey’s hsd test, a statistically signifi cant difference only between sampling group pb and all the other groups (kb and roff groups). however, there were no statistically signifi cant differences among the kb and roff groups. as shown in fig. 5 where the whisker box plot is presented, statistically signifi cant differences existed only between sampling group pb and the kb and/or the roff group. table 3: δ15n values of mytilus galloprovicialis collected in the murter sea, kosirina bay and pirovac bay (central adriatic) in august 2006. sampling group sampling site 30–50 mm δ15n ‰ 50–80 mm δ15n ‰ roff 1 reef flat lumbarda* + 3.3 roff 2 sedlo island + 3.6 roff 3 reef flat čavlin + 3.8 kb 4 kosirina bay + 4.2 + 4.1 kb 4 kosirina bay + 4.1 + 4.1 kb 4 kosirina bay + 4.3 + 4.2 pb 6 reef flat kušija + 6.0 pb 7 reef flat arta + 6.6 pb 13 port of murter 1 + 8.1 pb 13/1 port of murter 2 + 7.7 + 7.1 pb 9 reef flat spličak + 7.2 pb 10 prosika coast + 8.2 pb 11 sustipanac island + 7.3 pb 12 betina (marina) + 6.8 geologia croatica 64/2geologia croatica 148 figure 2: spatial distribution pattern of δ15n values of pom in june (a), july (b) and august 2006 (c) throughout kosirina bay (murter island). figure 3: whisker plots of δ15n values of pom samples collected in june (a), july (b) and august (c) 2006. dolenec et al.: use of stable nitrogen isotope signatures of anthropogenic organic matter in the coastal environment... geologia croatica 149 septic tanks are pumped out regularly (personal communication by director of autocamp kosirina boris paškvalin). ongoing sewage effl uent discharges (som and sob) into pirovac bay is therefore likely to lead to a comparatively greater δ15n enrichment relative to the south-western side of the murter island, including kosirina bay, which is open to the sea. flushing and tidal action as well as predominant currents in the kosirina bay have the effect of diluting and distributing the sewage effl uents. several studies suggested that ecosystems loaded by effl uents derived from human sewage should exhibit differences in the δ15n signal at each trophic level (risk & erdmann, 2000; spies et al., 1989; dolenec et al., 2006b). as the human and animal waste nitrate have a distinguishable nitrogen isotopic composition with δ15n values mostly in the range between +10 and +22 ‰ (heaton, 1986; kreit ler & browning, 1983), the elevated δ15n values of no3 > +10 ‰ are regarded as being indicative of faecal n origin (barret et al., 1999). this nitrogen is quickly assimilated by primary producers and transferred further into the entire food web including zooplankton, affecting their nitrogen isotopic composition (waser et al., 1998a, 1998b), which makes the pom indicative of the δ15n of the n substrate pool. elevated δ15n values have been identifi ed in pom and marine biota exposed to groundwater contaminated by septic wastes (mcclelland et al., 1997) and sewage effl uents (costanzo et al., 2001, risk & erdman, 2000; dolenec et al., 2005; risk & heikoop, 1997; waldron et al., 2001; hobson et al., 2002; dolenec et al., 2006a). increased δ15n values of about +7.9 ‰ were measured in pom dominated by untreated faecal matter of jepara bay (heikoop et al., 2000). similar values of about +8 ‰ were also found in pom near the infl ows from septic systems in the port of murter and in pirovac bay (dolenec et al., 2006a). the pom enriched in heavy nitrogen isotopes with δ15n values ranging from +6.1 to +8.6 ‰ was also measured during this study in pirovac bay. the pom generally represents a mixture of detrital material of marine and terrestrial origin, phytoand zooplankton and particulate effl uents from different sources. the background pom unaffected by anthropogenic activities may show seasonal variations in δ15n by several permil (bode & alvarez-ossorio, 2004). during this study, temporal differences in the δ15n of pom from reference and offshore locations of about 1.2 ‰ were also observed (tab. 1). however, these effects did not overprint the δ15n variability due to human sewage inputs in the studied area. temporal variations during the summer sampling season in the δ15n of the pom in pirovac bay were affected by human sewage inputs, by about 2.5 ‰ (tab. 1), and is most probably related to the variable inputs of effl uents with more or less constant δ15n values. previous study carried out on δ15n variability in the murter sea in 2005 revealed that the δ15n of pom tended to be lowest in the early part of the summer season, and higher during the late summer (at the end of august) (dolenec et al., 2006a). this pattern was not repeated in 2006. during this study, the pom sampled in august 2006 exhibited δ15n values, which tend to be depleted in 15n. this could be to figure 4: whisker plots of δ15n values of zooplankton collected at diff erent sampling sites in june 2006. figure 5: whisker plots of δ15n values of mytilus galloprovincialis collected at diff erent sampling sites in august 2006. 4. discussion the research revealed that pom and aquatic biota collected from pirovac bay (with a history of direct inputs of anthropogenic sewage effl uents), tended to have more positive δ15n values relative to pom and biota from kosirina bay, (receiving sewage effl uents and organic matter only by the sw-ne current pollutant transport). during the summer in kosirina bay is auto camp, which is serviced by adequate septic systems, which represent no additional impact of human sewage on the marine coastal ecosystem of the bay. there is no discharge of sewage into the sea because the plastic water geologia croatica 64/2geologia croatica 150 some extend the result of a very rainy august 2006, with a considerable input of rain water, which can alter the cycling of nutrients in the study area. higher δ15n values of pom detected in july in the ne part of the kosirina bay indicated the effl uents from the point source septic system, which accidentally at the time of the sampling period affected a limited part of the coastal water (fig. 2b). however, in august during the peak of the tourist season, the bay was relatively free from anthropogenicallyderived nitrogen due to a rainy august 2006 (fig. 2c). sewage effl uents from the septic systems enriched in heavy nitrogen could account for the 15n enrichment not only in pom but also in zooplankton and mussels from pirovac bay. for example, no3 – sewage waste shows signifi cantly higher δ15n values than other no3 – sources (heaton, 1986; macko & ostrom, 1994). zooplankton from pirovac bay (tab. 2) exhibiting the highest δ15n indicates a larger input of sewage wastes compared with zooplankton sampled in kosirina bay and/or on reference and other offshore locations. this indicates a signifi cantly lower input of sewage wastes as well as a considerable dispersion and dilution of the 15n-enriched wastes by sea currents along the sw part of the murter island. similarly, we can explain the nitrogen isotopic composition of mussels mytilus galloprovincialis (tab. 3). their δ15n are signifi cantly higher at the sampling sites in pirovac bay compared to individuals sampled in kosirina bay and at reference and/or offshore locations. this also suggest the same direction of change in δ15n, with more positive values in impacted than reference sites (costanzo et al., 2001; vizzini & mazzola, 2002; 2006). the spatial distribution of the anthropogenic impact indicators such as the δ15n signal in pom collected in june, july and august in kosirina bay (fig. 2), revealed a variable but only minor infl uence of human sewage in the bay. this could be related to anthropogenic organic matter, which most ly reached kosirina bay during southerly wind-driven sea currents from the sewage outfall south of tužbina island (soj). δ15n values also offer the possibility of estimating the trophic level of organisms, because δ15n values generally increase with increasing trophic position (fry, 1988; hobson & welch, 1992), but this 15n enrichment is variable; it varies between animal groups and is often diet-related (mccutchan et al., 2003; vanderklift & ponsard, 2003). in consumers, the trophic shift for nitrogen is about +1.4 ‰ for consumers feeding on an invertebrate diet and +3.3 ‰ for consumers feeding on a high-protein diet. the nitrogen trophic-shift for carnivorous fi sh is about +2.6 ‰ (mccutchan et al., 2003; vanderkleft & ponsard, 2003). the isotopic signature of the zooplankton and mussels follows the signature of pom, although the 15n enrichment in the system pom – zooplankton – mytilus galloprovincialis was not consistent with the predicted trophic pathway. to elucidate discrepancies, a further, more complex study and sampling programme is needed. 5. conclusion the results of this study provide a contribution to the broad debate on the problems relating to the anthropogenic n loading intensity on the coastal ecosystems of the murter sea and pirovac bay. this study revealed that 15n abundances in pom and biota were statistically signifi cantly different when comparing sampling sites in the less affected kosirina bay and offshore sites, as well as at reference location, with the anthropogenically most impacted pirovac bay, which is mostly affected by municipal wastes and untreated effl uents from the septic systems. by using the δ15n signature of pom, a spatial distribution of anthropogenically-derived nitrogen in kosirina bay was also mapped. based on results reported in the present study we can conclude that the shallow water marine ecosystem of kosirina bay was practically free from long-term anthropogenic impact of organic load, mostly origi nating from untreated wastes and effl uents from the septic systems. however, to get a better insight into the qualitative or quantitative shifts in the structure of the aquatic food web caused by pollutants, more extended research on the benthic population is needed, as well as a detailed investigation of temporal variations during the summer season of abundance and isotopic composition of pom and zooplankton as their presumed food source. acknowledgement this research was fi nancially supported by the slovenian research agency (arrs), republic of slovenia (research programmes p1-0195-1555 and p1-0143-0106 and the slovenian–croatian bilateral research cooperation programme, ministry of science, education and sports of the republic of croatia (project 0098132), and geoexp d.o.o., tržič, slovenia. the authors thank mr. boris paškvalin, director of htp betina, for his kind cooperation. thanks also to dr. paul mcguiness for linguistic corrections. a special thanks goes also to two reviewers, whose constructive comments signifi cantly contributed to raising the quality of the article. references alongi, d.m., chong, v.c., dixon, p., sasekumar, a. & tirendi, f. (2003): the infl uence of fi sh cage aquaculture on pelagic carbon fl ow and water chemistry in tidally dominated mangrove estuaries of peninsular malaysia.– mar. environm. res., 55, 313–333. doi:10.1016/s0141-1136(02)00276-3 alonso-rodriguez, r., paez-osuna, f. & cortes-altamirano, r. (2000): trophic conditions and stoichiometric nutrient balance in subtropical waters infl uenced by municipal sewage effl uents in mazatlan bay (se gulf of california).– mar. pollut. bull., 40, 331–339. doi:10.1016/s0025-326x(99)00225-8 bachtiar, t., coakley, j.p. & risk, m.j. (1996): tracing sewagecontaminated sediments in hamilton harbour using selected geochemical indicators.– science of the total environment, 179, 3–16. doi:10.1016/0048-9697(96)90045-5 barrett, m.h., hiscock, k.m., pedley, s., lerner, d.n., tel lam, j.h. & french, m.j. (1999): marker species for identifying urban groundwater recharge sources: a review and case study in nottingham, uk.– water res., 33, 3083–3097. doi:10.1016/s0043-1354(99)00021-4 dolenec et al.: use of stable nitrogen isotope signatures of anthropogenic organic matter in the coastal environment... geologia croatica 151 bode, a. & alvarez-ossorio, m.t. (2004): taxonomic versus trophic structure of mesozooplankton: a seasonal study of species succession and stable carbon and nitrogen isotopes in a coastal upwelling ecosystem.– ices j. mar. sci., 61, 563–571. doi: 10.1016/j. icesjms.2004.03.004 carmichael, r.h., annett, b. & valiela, i. (2004): nitrogen loading to pleasant bay, cape cod: application of models and stable isotopes to detect incipient nutrient enrichment of estuaries.– mar. pollut. bull., 48, 137–143. doi:10.1016/s0025-326x(03) 00372-2 costanzo, s.d., o’donohue, m.j., dennison, w.c., loneragan, n.r. & thomas, m. (2001): a new approach for detecting and mapping sewage impacts.– mar. pollut. bull., 42, 149– 156. doi:10.1016/s0025-326x(00)00125-9 costanzo, s.d., o’donohue, m.j. & dennison, w.c. (2000): gracilaria edulis (rhodophyta) as a biological indicator of pulsed nutrients in oligotrophic waters.– j. phycol., 36, 680–685. doi: 10.1046/ j.1529-8817.2000.99180.x costanzo, s.d., o’donohue, m.j. & dennison, w.c. (2003): assessing the seasonal infl uence of sewage and agricultural nutrient inputs in a subtropical river estuary.– estuaries, 26, 857–865. doi: 10.1007/bf02803344 davis, j.r. & koop, k. (2006): eutrophication in australian rivers, reservoirs and estuaries – a southern hemisphere perspective on the science and its implications.– hydrobiologia, 559, 23–76. doi: 10.1007/s10750-005-4429-2 deniro, m.i. & epstein, s. (1981): infl uence of diet on the distribution of carbon isotopes in animals.– geochim. cosmochim. ac., 45, 341–351. doi:10.1016/0016-7037(81)90244-1 dolenec, t., lojen, s., kniewald, g., dolenec, m. & rogan, n. (2007): nitrogen stable isotope composition as a tracer of fi sh farming in invertebrates aplysina aerophoba, balanus perforatus and anemonia sulcata in central adriatic.– aquaculture, 262, 237–249. doi:10.1016/j.aquaculture.2006.11.029 dolenec, t., lojen, s., lambaša, ž. & dolenec, m. (2006a): effects of fi sh farm loading on sea grass posidonia oceanica at vrgada island (central adriatic): a nitrogen stable isotope study.– isot. environ. healt. s., 42, 77–85. doi: 10.1080/10256010500384697 dolenec, t., lojen, s., dolenec, m., lambaša, ž., dobnikar, m., rogan, n. (2006b): 15n and 13c enrichment in balanus perforatus: tracers of municipal particulate waste in the murter sea (central adriatic, croatia).– acta chim. slov., 53, 469–476. dolenec, t., vokal, b. & dolenec, m. (2005): nitrogen – 15 signals of anthropogenic nutrient loading in anemonia sulcata as a possible indicator of human sewage impacts on marine coastal ecosystems: a case study of pirovac bay and the murter sea (central adriatic).– croat. chem. acta, 78, 593–600. evgenidou, a. & valiela, i. (2002): response of growth and densi ty of a population of geukensia demissa to land-derived nitrogen loading, in waquoit bay, massachusetts, estuarine.– coast. shelf sci., 55, 125–138. doi:10.1006/ecss.2001.0891 fogg, g.e., rolston, d.e., decker, d.l., louie, d.t., grismer, m.e. 1998: spatial variation in nitrogen isotope values beneath nitrate contamination sources.– ground water, 36, 418–426. doi: 10.1111/j.1745-6584.1998.tb02812.x fry, b. (1988): food web structure on georges bank from stable c, n, and s isotopic compositions.– limnol. oceanogr., 33, 1182–1190. gaston, t.f., kostoglidis, a. & suthers, i.m. (2004): the 13c, 15n and 34s signatures of a rocky reef planktivorous fi sh indicate different coastal discharges of sewage.– marine and freshwater research, 55, 689–699. doi:10.1071/mf03142 hadwen, w.l. & arthington, a.h. (2007): food webs of two intermittently open estuaries receiving 15n-enriched sewage effl uent.– estuar., coast. shelf s., 71, 347–358. doi: 10.1016/j.ecss. 2006.08.017 hansson, s., hobbie, j.e., elmgren, r., larsson, u., fry, b. & johansson, s. (1997): the stable nitrogen isotope ratio as a marker of food-web interactions and fi sh migration.– ecology, 78, 2249–2257. doi:10.1890/0012-9658 heaton, t.h.e. (1986): isotopic studies of nitrogen pollution in the hydrosphere and atmosphere: a review.– chem. geol., 59, 87–102. heikoop, j.m., risk, m.j., lazier, a.v., edinger, e.h., jompa, j., limmon, g.v., dunn, j.j., browne, d.r. & schwarcz, h.p. (2000): nitrogen-15 signals of anthropogenic nutrient loading in reef corals.– mar. pollut. bull., 40, 628–636. doi: 10.1016/ s0025-326x(00)00006-0 hobson & welch (1992): determination of trophic relationship within a high arctic marine food web using d13c and d15n analysis.– mar. ecol. prog. ser., 84, 9–18. hobson, k.a., fisk, a., karnovsky, n., holst, m., gagnon, j-m & fortier, m. (2002): a stable isotope (d13c, d15n) model for the north water food web: implications for evaluating trophodynamics and the fl ow of energy and contaminants.– deep-sea research part ii: topical studies in oceanography, 49, 5131–5150. doi:10.1016/s0967-0645(02)00182-0 howarth, r.w. (1998): an assessment of human infl uences on fl uxes of nitrogen from the terrestrial landscape to the estuaries and conti nental shelves of the north atlantic ocean.– nutr. cycl. agroecosys., 52, 213–223. doi: 10.1023/a:1009784210657 howarth, r.w., sharpley, a. & walker, d. (2002): sources of nutrient pollution to coastal waters in the united states: implications for achieving coastal water quality goals.– estuaries, 25, 656–676. doi: 10.1007/bf02804898 kendall, c. (1998): tracing nitrogen sources and cycling in catchments.– in: kendal, c. & mcdonnell, j.j. (eds.): isotope tracers in catchment hydrology. elsevier 1998, new york, 519–576. kreitler, c.w. & browning, l.a. (1983): nitrogen-isotope analysis of groundwater nitrate in carbonate aquifers: natural sources versus human pollution.– j. hydrol., 61, 285–301. doi: 10.1016/ 0022-1694(83)90254-8 kress, n., herut, b. & galil, b.s. (2004): sewage sludge impact on sediment quality and benthic assemblages off the mediterranean coast of israel a long-term study.– mar. environ. res., 57, 213–233. doi:10.1016/s0141-1136(03)00081-3 macko, s.a. & ostrom, n.e. (1994): pollution studies using stable isotopes.– in: lajtha, k. & michener, r.h. (eds.): stable isotopes in ecology and environmental science.– blackwell science, new york, 45–62. mcclelland, j.w., valiela, i. & michener, r.h. (1997): nitrogen-stable isotope signatures in estuarine food webs: a record of increasing urbanization in coastal watersheds.– limnol. oce anogr., 42, 930–937. mccutchan, j.h., lewis, w.m., kendall, c. & mcgrath, c.c. (2003): variation in trophic shift for stable isotope ratios of carbon, nitrogen, and sulfur.– oikos, 102, 378–390. muscatine, l. & kaplan, i.r. (1994): resource partitioning by reef corals as determined from stable isotope composition: ii. d15n of zooxanthellae and animal tissue versus depth.– pac. sci., 48, 304312. doi: 10.1007/bf00391957 nixon, s.w., oviatt, c.a., frithsen, j. & sullivan, b. (1986): nutrients and the productivity of estuarine and coastal marine ecosystems.– journal of the limnology society of south africa, 12, 43–71. doi: 10.1080/03779688.1986.9639398 owens, n.j.p. (1987): natural variations in n in the marine environment.– in: blaxter, j.h.s. & southward, a.j. (eds.): adv. mar. biol. academic press, 389–451. doi:10.1016/s0065-2881 (08)60077-2 pruell, r.j., taplin, b.k., lake, j.l. & jayaraman, s. (2006): nitrogen isotope ratios in estuarine biota collected along a nutrient geologia croatica 64/2geologia croatica 152 gradient in narragansett bay, rhode island, usa.– mar. pollut. bull., 52, 612–620. doi:10.1016/j.marpolbul.2005.10.009 rabalais, n.n. (2002): nitrogen in aquatic ecosystems, ambio.– j. hum. env., 31, 102–112. risk, m.j. & erdmann, m.v. (2000): isotopic composition of nitrogen in stomatopod (crustacea) tissues as an indicator of human sewage impacts on indonesian coral reefs.– mar. pollut. bull., 40, 50–58. risk, m.j. & heikoop, j.m. (1997): stable isotope ratios of nitrogen (d15n) as a measure of sewage stress on tropical coal reefs.– abstracts of papers of the american chemical society, 214, p. 68. rogers, k.m. (2003): stable carbon and nitrogen isotope signatures indicate recovery of marine biota from sewage pollution at moa point, new zealand.– mar. pollut. bull., 46, 821–827. doi: 10.1016/ s0025-326x(03)00097-3 ruiz, j.m., perez, m. & romero, j. (2001): effects of fish farm loadings on seagrass (posidonia oceanica) distribution, growth and photosynthesis.– mar. pollut. bull., 42, 749–760. doi: 10.1016/ s0025-326x(00)00215-0 schmidt, o. & ostle, n.j. (1999): tracing nitrogen derived from slurry in earthworms using 15n/14n stable isotope ratios at natural abundances.– appl. soil ecol., 12, 7–13. doi:10.1016/s0929-1393 (98)00160-7 sigleo, a.c. & macko, s.a. (2002): carbon and nitrogen isotopes in suspended particles and colloids, chesapeake and san francisco estuaries, u.s.a.– estuarine, coastal and shelf science, 54/4, 701–711. doi:10.1006/ecss.2001.0853 spies, r.b., kruger, h., ireland, r. & rice, d.w. (1989): stable isotope ratios and contaminant concentrations in a sewage-distorted food web.– mar. ecol. prog. ser., 54, 157–170. sutherland, t.f., martin, a.j. & levings, c.d. (2001): characte rization of suspended particulate matter surrounding a salmonid net-pen in the broughton archipelago, british columbia.– ices j. mar. sci., 58, 404–410. doi: 10.1006/jmsc.2000. 1043 tucker, j., sheats, n., giblin, a.e., hopkinson, c.s. & montoya, j.p. (1999): using stable isotopes to trace sewage-derived material through boston harbor and massachusetts bay.– mar. environ. res., 48, 353–375. doi:10.1016/s0141-1136 (99)00069-0 valiela, i. & bowen, j.l. (2002): nitrogen sources to watersheds and estuaries: role of land cover mosaics and losses within watersheds.– environ. pollut., 118, 239–248. doi:10.1016/s0269-7491 (01)00316-5 vanderklift, m.a. & ponsard, s. (2003): sources of variation in consumer-diet δ15n enrichment: a meta-analysis.– oecologia, 136, 169–182. doi: 10.1007/s00442-003-1270-z vitousek, p.m., aber, j.d., howarth, r.w., likens, g.e., mat son, p.a., schindler, w.h., schlesinger, w.h. & tilman, d.g. (1997): technical report: human alteration of the global nitrogen cycle: sources and consequences.– ecol. appl., 7/3, 737–750. doi:10.1890/1051-0761 vizzini, s. & mazzola, a. (2002): stable carbon and nitrogen ratios in the sand smelt from a mediterranean coastal area: feeding habits and effect of season and size.– j. fish biol., 60, 1498–1510. doi: 10.1111/j.1095-8649.2002.tb02443.x vizzini, s. & mazzola, a. (2006): the effects of anthropogenic organic matter inputs on stable carbon and nitrogen isotopes in organisms from different trophic levels in a southern mediterranean coas tal area.– science of the total environment, 368, 723–731. doi: 10.1016/j.scitotenv.2006.02.001 waldron, s., tatner, p., jack, i. & arnott, c. (2001): the impact of sewage discharge in a marine embayment: a stable isotope reconnaissance, estuarine and coastal shelf.– science, 52, 111–115. doi:10.1006/ecss.2000.0731 waser, n.a.d., harrison, p.j., nielsen, b., calvert, s.e. turpin, d.h. (1998a): nitrogen isotope fractionation during the uptake and assimilation of nitrate, nitrite, ammonium, and urea by a marine diatom.– limnol. oceanogr., 43/2, 215–224. waser, n.a.d., yin, k., yu, z., tada, k., harrison, p., turpin, d.h. calvert, s.e. (1998b): nitrogen isotope fractionation during nitrate, ammonium and urea uptake by marine diatoms and coccolithophores under various conditions of n availability.– mar. ecol. prog. ser., 169, 29–41. manuscript received january 26, 2010 revised manuscript accepted march 05, 2011 available online june 09, 2011 14-della.indd 163 �ab stra ct the effects of confi ning pressure, relative density and sample preparation methods on the shearing strength of chlef sand were studied. results are presented of drained and undrained monotonic triaxial compression tests, performed on samples with initial densities of 0.29 and 0.80, under initial confi ning pressures ranging from 50 to 200 kpa. specimens were prepared by two depositional methods; dry funnel pluviation and wet deposition. there was a marked dif ference in the undrained behaviour, even though the density and stress conditions were identical. the soil fabric was responsible for this result. the results also indicated that at low confi ning pressures, the specimens reconstituted by the wet deposition method exhibited complete static liquefaction, (zero effective confi ning pressure and zero stress dif ference). as confi ning pressures and densities were increased, the effective stress paths indicated increasing resistance to liquefaction by showing increasing dilatant tendencies. the same trends were observed in drained tests results in the form of an increase in the volumetric strain and the rapid transition from the contractancy phase to the dilatancy phase. keywords: liquefaction, sand, drained, undrained, dry funnel pluviation, wet deposition, confi nement, density, residual strength, volumetric strain. drained and undrained shear strength of silty sand: eff ect of reconstitution methods and other parameters � noureddine della, ahmed arab and mostefa belkhatir laboratory of material sciences and environment, civil engineering department, university of chlef, sendjas street pobox 151 chlef 02000 – algeria (nour_della@yahoo.fr) doi: 104154/gc.2011.14 geologia croatica 64/2 163–171 18 figs. 1 tab. zagreb 2011 geologia croaticageologia croatica european and african plates as shown by fig. 1, is constantly a very unstable zone subjected to intense seismic activity. on october 10th, 1980 at 13h25 (local time), the region was hit by a disastrous earthquake of magnitude of 7.3 according to the calculations of papastamatiou (1980), followed by strong aftershocks of magnitudes 6 and 6.1 some hours afterwards, and numerous more aftershocks during se veral subsequent months (ouyed, 1981). the main shock generated an important inverse fault, about 40 km long, appearing on the surface (ambraseys, 1981). the epicenter of this earthquake was localized in the north east of el-asnam. the disaster of october 10, 1980 resulted in heavy loss of life (about 3000 deaths), the destruction of a large number of buildings, important damage to the linking infrastructures and to public equipment, and generated a certain number of 1. introduction during static or cyclic loading, the shaking of the ground may cause saturated cohesionless soils to lose their strength and behave like a liquid. this phenomenon is called soil liquefaction and will cause settlement or tipping of buildings, failure of earth dams, earth structures and slopes. the modern study of soil liquefaction has been triggered by numerous liquefaction-induced failures during the 1964 niigata, japan earthquake. therefore, it is necessary to obtain a proper understanding of the effect of parameters such as soil pro perties and the nature of the loading on the severity of soil liquefaction. the region of chlef situated near the mediterranean sea, to the north of algeria, about 200 km to the west of the capital algiers, by its proximity to the contact of the continental geologia croatica 64/2geologia croatica 164 geodynamic phenomena at the surface of the ground: ground movements of variable nature and size, and especially the liquefaction of the sandy soils following a loss of shearing resistance. the phenomenon of liquefaction appeared on a vast alluvial valley crossed by the chlef river and at the confl uence of this river with the fodda river as shown in fig. 2 (durville & meneroud, 1982). 2. prior studies numerous studies have reported that the behaviour of sands can be greatly infl uenced by the initial state of the soil. polito & martin (2003) asserted that the relative density and skeleton void ratio were factors that seemed to explain the variation in different experimental results. yamamu ro & lade (1997), yamamuro & lade (1998) and yama muro & covert (2001) concluded that complete static liquefaction, (zero effective confi ning pressure and zero effective stress difference) in laboratory testing, is most easily achieved in silty sands at very low pressures. kramer & seed (1988) also observed that liquefaction resistance increased with increasing confi ning pressure. several specimen reconstitution techniques, tamping and pluviation being the most common, are in use in current practice. the objective in all of these is to replicate a uniform sand figure 1: movement of the europe-african plate (from the ctc institution – controle technique de construction). figure 2: valley of the chlef river and localization of sand boils due to liquefaction (from the ctc institution – controle technique de construction). della et al.: drained and undrained shear strength of silty sand: eff ect of reconstitution methods and other parameters geologia croatica 165 specimen at the desired void ratio and effective stresses to simulate the sand mass in-situ. however the effect of the preparation method of the samples has been subject to controversial research. many studies have reported that the resistance to liquefaction is higher for samples prepared by the method of sedimentation than for samples prepared by dry funnel pluviation and wet deposition (zlatovic & ishihara, 1997); other studies have found that the specimens prepared by the dry funnel pluviation method tend to be less resistant than those reconstituted by the wet deposition meth od (mulilis et al., 1977; yamamuro & wood, 2004). other researchers indicated that the tests prepared by dry funnel pluviation are more stable and dilatant than those prepared by wet deposition (benahmed et al., 2004; ca nou, 1989; ishihara, 1993). vaid et al. (1999) confi rm this result while showing that wet deposition encourages the initiation of liquefaction in relation to a setting up by pluviation under water. yamamuro et al. (2008) concluded after their laboratory investigation, that the method of dry pluviation supports the instability of the samples contrary to the method of sedimentation. wood et al. (2008) found that the effect of the method of deposition on the undrained behaviour decreases, when the density increases. they also found that this infl uence decreases with the increase in fi nes content, particularly at lower densities. the focus of this study is to identify the differences in drained and undrained triaxial compression behaviour that can result from using different reconstitution techniques to create silty sand specimens. 3. experimental methods an experimental study of the behaviour of loose and dense sand under static loading conditions is presented below. both drained and undrained tests were performed. 3.1. sand tested silty sand samples were collected from the liquefi ed layer of the study areas at a depth of 6.0 m (fig. 3) close to the chlef earthquake epicentre (october 10th, 1980). figs. 4a,b show craters of liquefi ed ground on the banks of the chlef figure 3: geotechnical profi le of the soil deposit at the site. figure 4: craters of liquefi ed soil on banks of the river chlef (a and b). river. fig. 5 illustrates a typical subsidence location of the liquefi ed soil and sample collection. all tests in the present study were performed on sand from chlef (algeria). the sand contains 0.5% silt of the river chlef. the grain size distribution curve of this sand is given in fig. 6. it is medium sand with rounded grains of medium diameter d50 = 0.45 mm and the predominant minerals are feldspar and quartz. the silt component is non plastic with a plasticity index of 5.81 %. the index properties of the sand used in this laboratory research work are presented in table 1. the specimens were reconstituted at two densities (id = 0.29 and 0.80) representing the loose and dense states. figure 5: subsidence of the chlef river banks due to liquefaction. a) b) geologia croatica 64/2geologia croatica 166 3.2. testing equipment an advanced automated triaxial testing apparatus, type bish op and wesley (bishop & wesley, 1975) was used to conduct the monotonic drained and undrained tests (fig. 7). 3.3. specimen preparation in this study, two methods of sample preparation, which included dry funnel pluviation (dfp) and wet deposition (wd), were utilized, and as briefl y described below. in the fi rst method, dry soil is deposited in the mould with the help of a funnel by controlling the height; this meth od consists of fi lling the mould by tipping in a rain of dry sand. to have loose samples, it is necessary that the fall height is almost nil. the second method consists of mixing the previously dried sand with a small quantity of water (3 %) and then depositing the humid soil in the mould in a manner that is as homogenous as possible. the soil was placed in successive layers. a constant number of strokes were applied to get a homogeneous and isotropic structure. triaxial tests were performed on cylindrical specimens measuring 70 mm in diameter and 140 mm in height (h/d = 2.0). the mass of sand to put in place is determined according to the desired density (the initial volume of the sample is known). the density state of the sample was defi ned by the density index: id = (emax – e) / (emax – emin) [1] where emin and emax indicate the minimum and maximum void ratios, respectively; e is the target void ratio and id the density index. after the specimen has been formed, the specimen cap is placed and sealed with o-rings, and a partial vacuum of 15 to 25 kpa is applied to the specimen to reduce the disturbances. 3.4. saturation and consolidation saturation of the specimens was accomplished by fl ushing the specimen with carbon dioxide for approximately 20 min (lade & duncan, 1973), after which de-aerated water was slowly added from the bottom of the specimen. application of a back pressure improves the degree of saturation which was estimated by calculating skempton’s b-parameter as the ratio of measured pore water pressure increase, induced by an increase in cell pressure in undrained conditions, and the corresponding increase in cell pressure. the b value was measured to test specimen saturation, and a minimum value greater than 0.96 was obtained for all tests. the triaxial test samples were isotropically consolidated under confi ning pressures ranging from 50 to 200 kpa prior to static loading. 3.5. shear loading all drained and undrained triaxial tests for this study were carried out at a constant strain of 0.167 % per minute, which was slow enough to allow pore pressure change to equalize throughout the sample with the pore pressure measured at the base of sample. all the tests were continued up to 20 % axial strain. 4. results of undrained triaxial compression tests 4.1. eff ect of confi ning pressure and density for the purpose of studying the effect of variation of effective confi ning pressure on liquefaction resistance, a series of figure 6: grain-size distribution curve of tested material. figure 7: the triaxial system set up. table 1: index properties of the used sand. material emin emax gdmin gdmax gs cu d50 d10 grains shape o/chlef 0.54 0.99 13.4 17.3 26.7 3.2 0.45 0.15 rounded della et al.: drained and undrained shear strength of silty sand: eff ect of reconstitution methods and other parameters geologia croatica 167 tests were conducted. figs. 8 and 9 show the results of the undrained triaxial compression tests performed. all tests were performed on specimens composed of chlef sand, and each specimen was monotonically loaded in compression under undrained conditions. figs. 8a and 9a present the undrained stress-strain curves, while figs. 8b and 9b show the effective stress paths on the cambridge p’-q diagram in which p’=(σ’1+2σ’3)/3 and q= σ’1σ’3. it is noticed that as the confi ning pressures increased, the liquefaction resistance, (deviatoric stress), increased for both dry funnel pluviation and wet deposition methods. as can be seen for the samples reconstituted by the wet deposition method, complete static liquefaction occurred in two tests at the lowest confi ning pressure (50 kpa) irrespective of sand densities. static liquefaction was coincidental with the formation of large wrinkles in the membranes surrounding the specimens. at a confi ning pressure of 100 kpa the specimens undergo temporary liquefaction characterized by the condition where the undrain ed stress difference fi rst achieves an initial peak, after which it declines to a minimum value. finally, at a confi ning pressure of 200 kpa the resistance to liquefaction increases for both loose and dense samples. in figures 8 and 9 for the dry funnel pluviation method, it is clear that when the initial confi ning pressure is increased from 50 kpa to 200 kpa, specimens with a density index of either 0.29 (loose) or 0.80 (dense) exhibit behaviour that is characterised by increasing stability or increasing resistance to liquefaction. the effect of increasing confi ning pressure is to increase the dilatant tendencies in the soil. temporary liquefaction is described as the condition where the undrained stress difference fi rst achieves an initial peak, after which it declines to a minimum value. this is caused by rapidly rising pore pressure which decreases the effective stress. increasing dilatancy or resistance to liquefaction can also be observed by examining the ratio of the minimum stress difference to the initial peak stress difference, (q(min)/q(peak)) shown in fig. 10 for the wet deposition method. a q(min)/ q(peak) ratio of zero indicates complete liquefaction, and a q(min)/q(peak) ratio of unity represents completely stable behaviour. the inset diagrams in figs. 10a and 10b show that this ratio is zero at initial confi ning pressure of 50 kpa, indicating complete static liquefaction. the ratio then increases at initial confi ning pressures from 100 to 200 kpa, indicating that the specimen exhibits more dilatancy and, thereby, is more resistant to liquefaction. figure 11 illustrates the variation of the maximum undrained shear strength (qmax) with the initial density (id) at various confi ning pressures. it is clear from this fi gure that an increase in the relative density results in an increase in the maximum strength at a given confi ning pressure for both dry funnel pluviation and wet deposition, with a more pronounced increase for the method of dry funnel pluviation (fig. 11a), contrary to the case of wet deposited samples where the evolution of the resistance is less pronounced (fig. 11b). thevanayagam et al. (1997) and sitharam et al. (2004) report similar behaviour of increasing undrained shear strength with increasing relative density. figure 8: undrained tests on loose sand: (a) deviator stress-strain curve, (b) stress path; dfp= dry funnel pluviation, wd= wet deposition figure 9: undrained tests on dense sand: (a) deviator stress-strain curve, (b) stress path; dfp= dry funnel pluviation, wd= wet deposition a) b) a) b) geologia croatica 64/2geologia croatica 168 figure 10: resistance to liquefaction for the wet deposition method: (a) loose state, (b) dense state figure 11: eff ect of the relative density on the undrained response of sand. 4.2. eff ect of the method of deposition figure 12 shows the variation of the undrained shear strength at the peak (qpeak) with the effective confi ning pressures using two methods of deposition. it can be seen from this fi gure that the dry funnel pluviation method shows higher values of the deviator at peak strain, therefore a much higher resistance to liquefaction, contrary to the wet deposition method where we note some lower values of the deviator at peak for low densities (loose state for id = 0.29), with progressive stabilization around a very small or nil ultimate stationary value representing liquefaction of the sample. when loose and medium dense sandy soils are subjected to undrained loading beyond the point of peak strength, the undrained shear strength declines to a near constant value over large deformation. conventionally, this shear strength is called the undrained steady-state shear strength or residual shear strength. however, if the shear strength increases after passing through a minimum value, the phenomenon is called limited or quasi-liquefaction. even limited liquefaction may result in a signifi cant strain and associated drop in resistance. ishihara (1993) defi ned the residual shear strength sus as: sus = (qs/2)cosφs = (m/2) cosφs(ps’) [2] m = (6 sinφs)/(3sinφs) [3] where qs, ps’ and φs indicate the deviator stress (σ1’σ3’), the effective mean principal stress (σ1’+ 2σ3’)/3, and the mofigure 12: eff ect of the deposition methods on the undrained shear strength at the peak. a) b) a) b) a) b) della et al.: drained and undrained shear strength of silty sand: eff ect of reconstitution methods and other parameters geologia croatica 169 bilized angle of inter-particle friction at the quasi-steady state (qss) respectively. for the undrained tests conducted at a constant confi ning pressure and various initial relative densities and fi nes content, the deviatoric stress (qs) was estimated at a quasi-steady state point along with the mobilized internal friction angle (fig. 13). furthermore, the residual shear strength was calculated according to the relationship [2]. figure 14 shows the evaluated undrained residual shear strength (sus) and its variation with confi ning pressures and the reconstitution methods. it is clear from this fi gure that the sample preparation method considerably affects the evolution of the residual strength. indeed this residual strength is nil for the samples prepared by wet deposition to a confi nement of 50 kpa because of the collapse of samples, but for confi nements of 100 and 200 kpa, the samples prepared by dry funnel pluviation mobilize a more signifi cant residual strength than those prepared by wet deposition. 5. results of drained triaxial compression tests figures 15 and 16 show the results of the drained tests on samples prepared by the method of dry funnel pluviation with two densities (id=0.29 and 0.80). fig. 15 shows that the resistance to liquefaction represented by deviatoric stress increases with an increase in the confi ning pressure and density. fig. 16 shows the evolution of the volumetric strain ver sus the axial strain. we note that the increase in the density accelerates the transition from the contractancy phase to the dilatancy phase. the same tendencies can be observed in figs. 17 and 18 which show the results of the drained tests on specimens reconstituted by the wet deposition method. as can be seen from fig. 17 the resistance to liquefaction represented by the deviatoric stress, increases with an increase in the confi ning pressure and density. fig. 18 shows the evolution of the volumetric strain versus axial strain. it can be noticed that the method of wet deposition increases the phase of contractancy. this increase in the phase of contractancy is highly marked for the loose specimens (fig. 18a). by comparing the results of figs. 15−18, we concluded that the specimens reconstituted by the dry funnel pluviation method were more dilatant than those prepared by the wet deposition method. the results of the drained and undrained tests are in perfect agreement with those given by benahmed et al. (2004) and ishihara (1993) who discovered that samples prepared by dry funnel pluviation have a resistance to liquefaction higher than those prepared by wet deposition. zlatovic & ishihara (1997) discovered that the resistance of the samples prepared by the method of dry funnel pluviation decreases with the increase in the fraction of fi nes, while the samples prepared by sedimentation showed a reduction in resistance until a fi nes content of fc=30%, then increase. mulilis et al. (1977) concluded from their study, that the samples prepared by wet tamping present a resistance higher than those prepared by dry funnel pluviation. these differences of behaviour noted between the two methods of deposition, can be explained by the fact that the figure 13: determination of the phase transition point. figure 14: eff ect of the deposition method on the undrained residual shear strength. a) b) geologia croatica 64/2geologia croatica 170 figure 15: dry funnel pluviation − evolution of the deviatoric stress versus axial strain: (a) loose state (id =0.29), (b) dense state (id =0.80). figure 17: wet deposition − evolution of the deviatoric stress versus axial strain: (a) loose state (id =0.29); (b) dense state (id =0.80). figure 16: dry funnel pluviation – evolution of the volumetric strain versus axial strain: (a) loose state (id =0.29), (b) dense state (id =0.80). figure 18: wet deposition – evolution of the volumetric strain versus axial strain: (a) loose state (dr =0.29), (b) dense state (dr=0.80). a) b) a) b) a) b) a) b) della et al.: drained and undrained shear strength of silty sand: eff ect of reconstitution methods and other parameters geologia croatica 171 molecules of water contained in the structures prepared by wet deposition method prevent grain-grain adhesion. this trend accelerates the instability of the samples which show a very weak resistance and even provokes the phenomenon of liquefaction of the sand for low densities and low confi nements leading to the collapse of the sample. this is contrary to the structures of samples prepared by the method of dry funnel pluviation that show a more dilatory behaviour. 6. conclusion a series of drained and undrained triaxial compression tests in monotonic loading conditions were performed on silty sand samples retrieved from liquefi ed sites on the chlef river banks (algeria). the effects of sample preparation methods and other parameters were studied. the study included drain ed and undrained triaxial tests that have been prepared at den sities of 0.29 and 0.80 for confi nements of 50,100 and 200 kpa. bas ed on the experimental results presented, the following conclusions can be drawn: 1. complete static liquefaction occurred at low confi ning pressure (50 kpa) for the wet deposition method. 2. as the confi ning pressure increased, the liquefaction resistance of the sand increased for both dry funnel pluviation and wet deposition. this observation correlates with most historic cases of apparent static and earthquake-induced liquefaction. 3. an increase in the density resulted in an increase in the maximum undrained shear strength of the sand in undrained tests, and accelerates the transition from the contractancy phase to the dilatancy phase in drained tests. 4. the peak and residual shear strengths of sand are sensitive to the sample preparation methods. the dry funnel pluviation method gives higher values of the peak and residual shear strengths than the wet deposition method. 5. the results also reveal that the method of reconstitution has a detectable effect on the drained behaviour of the sand in terms of volumetric strains. the dry funnel pluviation method appeared to indicate a more volumetrically dilatant or stable response, while the wet deposition method appeared to exhibit a more contractive or unstable behaviour. references ambraseys, n.n. (1981): the el-asnam earthquake of 10 october 1980: conclusions drawn from a fi eld study.− q. j. eng. geol., london, 14, 143−148. benahmed, n., canou, j. & dupla, j.c. (2004): structure initiale et propriétés de liquéfaction statique d’un sable.− comptes rendus mécanique, 332, 887−894. doi: 10.1016/j.crme.2004.07.009. bishop, a.w. & wesley, l.d. (1975): a hydraulic triaxial apparatus for controlled stress path testing.− géotechnique, 25, 657–670. doi: 10.1680/geot.1975.25.4.657. canou, j. (1989): contribution l’étude et à l’évaluation des propriétés de liquéfaction d’un sable, thèse de doctorat de l’ecole nationale des ponts et chaussées, paris. durville, j.l. & meneroud, j.p. (1982): phénomènes géomorphologiques induits par le séisme d’el-asnam, algérie.− bull. liaison labo. p. et ch., 120, juillet-août, 13−23. ishihara, k. (1993): liquefaction and fl ow failure during earthquakes.− géotechnique, 43/3, 351−415. doi: 10.1680/geot.1993.43.3.351. kramer, s.l. & seed, h.b. (1988): initiation of soil liquefaction under static loading conditions.− j. geotech. engin., 114/4, 412−430. doi: 10.1061/(asce)0733-9410(1988)114:4(412). lade, p.v. & duncan, j.m. (1973): cubical triaxial tests on cohesionless soil.− journal soil mechanics and foundations division asce, 99/sm10, 793−812. mulilis, j.p., seed, h.b., chan, c.k., mitchel, j.k. & arulanadan, k. (1977): effects of sample preparation on sand liquefaction.− j. geotech. engin. div., asce, 103, 91−108. ouyed, m. (1981): le tremblement de terre d’el-asnam du 10 octobre 1980: étude des répliques.− unpubl. phd thesis, university of grenoble, grenoble, 200 p. (in french). papastamatiou, d. (1980): el-asnam, algeria earthquake of october 10, 1980: fi eld evidence of ground motion in the epicentral region.− geognosis ltd., london. polito, c.p. & martin, ii j.r. (2003): a reconciliation of the effects of non-plastic fi nes on the liquefaction resistance of sands reported in the literature.− earthquake spectra, 19/3, 635−651. doi:10.1193/ 1.1597878. sitharam, t.g., govinda, r.l. & srinivasa, m.b.r. (2004): cyclic and monotonic undrained shear response of silty sand from bhuj region in india.− iset j. earth. tech. pap., 450/41, 249−260. thevanayagam, s., ravishankar, k. & mohan, s. (1997): effects of fi nes on monotonic undrained shear strength of sandy soils.− astm geotech. test. j., 20/1, 394−406. doi: 10.1520/ gtj10406j. vaid, y.p., sivathayalan, s. & stedman, d. (1999): infl uence of specimen reconstituting method on the undrained response of sand.− geotech. test. j., 22/3, 187−195. doi: 10.1520/gtj11110j. wood, f.m., yamamuro, j.a. & lade, p.v. (2008): effect of depositional method on the undrained response of silty sand.− can. geotech. j., 45/11, 1525–1537. doi: 10.1139/t08-079. yamamuro, j.a. & covert, k.m. (2001): monotonic and cyclic liquefaction of very loose sands with high silt content.− j. geotech. geoenviron. engin. asce, 127/4, 314− 324. doi: 10.1061/(asce) 1090-0241(2001)127:4(314). yamamuro, j.a. & lade, p.v. (1997): static liquefaction of very loose sands.− can. geotech. j., 34/6, 905−917. doi: 10.1139/cgj34-6-905. yamamuro, j.a. & lade, p.v. (1998): steady state concepts and static liquefaction of silty sands.– j. geotech. geo environmental engineering asce, 124/9, 868–877. doi:10.1061/(asce) 10900241(1998)124:9(868). yamamuro, j.a. & wood, f.m. (2004): effect of depositional meth od on the undained behaviour and microstructure of sand with silt.– soil dyn. earthq. eng., 24, 751–760. yamamuro, j.a., wood, f.m. & lade, p.v. (2008): effect of deposi tional method on the microstructure of silty sand.– can. geo tech. j., 45/11, 1538–1555. doi: 10.1016/j.soildyn. 2004.06.004. zlatovic, s. & ishihara, k. (1997): normalized behaviour of very loose non-plastic soils: effects of fabric.– soils found., 37/4, 47–56. manuscript received march 05, 2010 revised manuscript accepted february 24, 2011 available online june 09, 2011 geologia croatica 64/2geologia croatica 172 13-horvat.indd 153 � ab stra ct potassium feldspars from different granitoids and gneisses of papuk mt. (slavonia, croatia) have been investigated by x-ray powder diffraction. diffraction patterns classically observed as well as patterns calculated by rietveld refi nement were compared and discussed. triclinicity was calculated according to goldschmidt & laves (1954) while the structural state of the feldspars was determined using the methods of kroll & ribbe (1983) and godinho & jaleco (1973). results showed that the type of potassium feldspar depend on the investigated host-rock, indicating variation in the structural state from orthoclase, intermediate microcline to highly ordered microcline. potassium feldspar megacrysts in biotite-granodiorites and monzogranites are intermediate microcline or orthoclase, while two-mica monzogranites contain low microcline. gneisses contain low microcline and orthoclase in brzaja creek and low microcline in djedovica quarry. classically observed and digital diffraction patterns calculated by the rietveld refi nement method produced comparable results and provided a very good correlation of the results obtained by different methods. high triclinicity values of feldspars from investigated granitoid and gneiss samples from papuk mt. (slavonia, croatia) are in accordance with a high al content in the t1o site and their fully ordered state indicates a slow(er) cooling-rate. low triclinicity values, an al content in t1o site around 0.60 and ordering index smaller than 0.80 can be interpreted as a result of relatively fast(er) cooling which allowed lower ordering of the potassium feldspar. keywords: x-ray powder diffraction, potassium feldspars, triclinicity, structural state, ordering index, granitoids and gnesses, papuk mt., croatia x-ray study of potassium feldspars from diff erent granitoid types and gneisses of papuk mt. (slavonia, croatia) � marija horvat1, darko tibljaš2, györgy buda3 and györgy lovas3 1vukomerečka cesta 55a, 10040 zagreb, croatia; (horvatmarija@hotmail.com) 2department of geology, faculty of science, horvatovac 95, hr-10000 zagreb, croatia; (dtibljas@geol.pmf.hr) 3department of mineralogy, eötvös loránd university, pázmány péter st. 1/c, h-1171 budapest, hungary; (buda@ludens.elte.hu; lovas@ludens.elte.hu) doi: 104154/gc.2011.13 geologia croatica 64/2 153–162 4 figs. 2 tabs. zagreb 2011 geologia croaticageologia croatica called triclinicity (∆) (goldschmidt & laves, 1954). wright & stewart (1968), developed a method which was revised by stewart & wright (1974) that uses b and c cell edges and α* and β* cell angles for estimations of obliquity. kroll (1971, 1973 and 1980) and kroll & ribbe (1983) developed the method for calculating al occupancy of tetrahedral sites based on lattice translations along [110] 1. introduction x-ray powder diffraction is the most common method for determining symmetry and ordering of potassium feldspars. for monoclinic crystals the hkl and hk̄l refl ections show a single sharp peak on the diffraction pattern. for triclinic crystals the hkl and hk̄l peaks have different 2θ values and form a double peak. in the case of alkali feldspars, the splitting of the 131 and 13̄1, that occur at ~29.9° 2θ cukα, is geologia croatica 64/2geologia croatica 154 and [11̄0] directions: named tr [110] and tr [11̄0], respectively. assuming that the angular difference of 2̄04 and 060 peaks, in the 29–31° region changes linearly with degree of order, godinho & jaleco (1973) defi ned an ordering index (∆sm) based on this difference. various potassium feldspar polymorphs and their structural states, from the different granitoid types and gneisses found at papuk mt. in croatia are presented (fig. 1). results obtained from the classically observed and digital x-ray diffraction patterns calculated by rietveld refi nement are compared. for both of these patterns goldschmidt & la ves’s (1954) triclinicity and kroll & ribbe’s (1983) ordering path calculations were undertaken and are discuss ed. re sults for the t1o site occupancy estimated by kroll & ribbe’s (1983) method, are compared with the results calculated by neves & godinho’s (1995) formulae. finally, the structural state of these feldspars derived from triclinicity and al occupancy of tetrahedral sites is discussed. 2. geological setting papuk mt. is part of the slavonian mountains in croatia which are located in the southernmost part of the pannonian basin in the bihor nappe system (fig. 1) of tisza mega-unit (schmid et al., 2008). the published geological maps 1:100 000, orahovica sheet (jamičić & brkić, 1987) and daruvar sheet jamičić (1989), report that it is primarily composed of metamorphic and granitoid rocks. the main mi neralogical features, geochemistry and detailed structural-tectonic investigations of granitoids and related gneisses and pegmatites in the area are discussed in many papers, including; tajder (1957), raffaelli (1965), vragović (1965), tajder (1969), slovenec (1976, 1978, 1982, 1984), jamičić (1983, 1995, 2001), pamić & lanphere (1991), pamić et al. (1988, 1996), horvat et al. (2002), horvat (2004), horvat & buda (2004), balen et al. (2006), biševac et al. (2009), biševac et al. (2010), hor váth et al. (2010). feldspars are the most abundant minerals in these rocks. figure 1: (a) segment of the map (schmid et al., 2008) showing the major tectonic units of the alps, carpathians, dinarides and hellenides with the position of papuk mt. within the tisza mega-unit composed of the mecsek, bihor and codru nappe systems. (b) a section of the geological map of the slavonian mts. (papuk, krndija, ravna gora and psunj) (jamičić, 2001) with sampling localities (table 1). legend: 1 – main tectonic lines; 2 – alluvium of creeks; 3 – deluvial-proluvial deposits; 4 – loess; 5 – pliocene-quaternary: gravel and sands; 6 – albite rhyolite, andesite, basalt; 7 – pontian: sand, marl and clay; 8 – sarmatian-pannonian: marl and limestone; 9 – badenian: conglomerate, limestone, marl; 10 – karpatian: conglomerate, sand, clay and marl; 11 – ottnangian: conglomerate, sand, gravel; 12 – upper cretaceous: sandstone and limestone; 13 – granite of požeška gora; 14 – jurassic: limestone; 15 – middle and upper triassic: dolomite, dolomitic limestone; 16 – lower triassic: sandstone, siltstone, shale; 17 – permotriassic: quartz sandstone, conglomerate; 18 – devonian-carboniferous: graphitic schist, conglomerate, sandstone, siltstone; 19 – granitoids; 20 – gneiss; 21 – migmatite; 22 – (precambrian): chlorite-sericite schist, metagabbro, marble, amphibolite, amphibole-schist, phlaseride granitoid, garnet-staurolite gneiss. horvat et al.: x-ray study of potassium feldspars from diff erent granitoid types and gneisses of papuk mt. (slavonia, croatia) geologia croatica 155 a short review about the previous study of feldspars in this area can be found in and kovács kis et al. (2004) and references within. 3. materials and methods various types of granitoid and gneiss rock samples (table 1) were collected from several valleys on papuk mt. sampling localities are shown on the compiled geological map in figure 1. the potassium feldspars from the aforementioned rocks were differentiated by x-ray powder diffraction measurements. x-ray investigation included measurement and indexing of the x-ray powder diffraction patterns of two kinds of materials: (1) non-magnetic, low density separates of fi ner-grained rocks (a mixture of quartz, alkali feldspar and plagioclase, i.e. felsic components that were impossible to separate from each other by hand-picking under the stereomicroscope) and (2) feldspar megacrysts picked out from four samples that are representative for different granitoid types and localities. (1) the separates were prepared by crushing and wet sieving followed by heavy liquid (bromoform) separation of either the 0.25–0.125 mm or 0.125–0.063 mm fractions. the light fraction was further cleaned by a frantz isodynamic magnetic separator (model li). separates that contained kfeldspar, plagioclase and quartz grains, were pulverised in an agate mortar. x-ray powder diffraction patterns were obtained on an analogue siemens d500 powder diffractometer in the 5° to 65° 2θ range. instrumental parameters were: cukα radiation, 40 kv, 20 ma, ni fi lter, registration at 0.5° 2θ/min goniometer, 1 cm/min chart speed, 2×103 sensitivity and 0.1 mm detector aperture. nacl was used as zero shift internal table 1: list of investigated samples showing locality, rock type and triclinicity values (δ = 12.5*[d(131)-d(13̄1)]) calculated according to goldschmidt & laves (1954), for potassium feldspars from: (1) non-magnetic, low density fractions of bulk rock (mixture of quartz, alkali feldspar and plagioclase) and (2) megacrysts from porphyric rock types. (a,b) two megacrysts from one rock sample. determination of mineral phases was according to the following reference data: quartz (q) – jcpds 33-1161; low albite (la) – jcpds 20-0554; albite, calcian (a) – jcpds 20-0548 ; low microcline (lm), intermediate microcline (im) and orthoclase (o) from borg & smith (1969); muscovite (ms) from grim, bray & bradley (1937) in brown (1961) and chlorite (chl) from shirozu (1958) in brown (1961). locality (fig. 1) sample name rock type (based on mineralogical and/or geochemical data) determined mineral phases in classical x-ray pattern (1) δ calculated from classical diff raction pattern (1) δ calculated from rietveld refi nement diff raction pattern (2) brzaja creek ppm-3 gneiss lm, o, la, q, ms 0.92 brzaja creek ppg-4 granodiorite lm, la, q, ms 0.87 brzaja creek ppm-5 gneiss o, lm, la, q 0 brzaja creek ppg-8 two-mica monzogranite lm, la, q 0.81 0.96 brzaja creek ppm-9 gneiss o, a, q, ms 0 brzaja creek ppg-12 two-mica monzogranite lm, la, q, ms 0.87 djedovica quarry pp-13/1 gneiss lm, la, q, ms, chl 0.92 djedovica quarry pp-13/2 gneiss lm, la, q, ms, chl 0.96 djedovica quarry pp-13/4 gneiss lm, a, q, ms, chl 0.97 djedovica quarry pp-13/5 gneiss lm, la, q, ms 1 djedovica quarry pp-13/6 gneiss lm, la, q, ms 0.90 pakra creek 2ppg-3 porphyric granodiorite o, a, q 0 pakra creek 2ppg-4 porphyric granodiorite o, a, im, q, ms 0 pakra creek 2ppg-5 porphyric granodiorite im, a, q, ms 0.29 0.33 pakra creek 2ppg-6 (a) porphyric granodiorite o/im, a, q, ms 0 pakra creek 2ppg-6 (b) porphyric granodiorite o/im, a, q, ms 0 pakra creek ppg-19 granodiorite o, la, q, ms 0 0 pakra creek ppg-24 porphyric granodiorite im, a, q 0.32 0.29 pakra creek ppg-18 two-mica monzogranite lm, o, la, q, ms 0.87 pakra creek ppg-20 monzogranite lm, a, q, ms, chl 0.70 0.72 pakra creek ppg-23 two-mica granodiorite lm, la, q, ms 0.56 šandrovac creek 2ppg-32 two-mica monzogranite lm, o, la, q, ms 0.83 rajčevica creek 2ppg-33 monzogranite lm, la, q, ms, chl 0.68 kišeljevac creek heg-31 biotite monzogranite lm, o, la, ms, chl 0.88 geologia croatica 64/2geologia croatica 156 figure 2: the {131} diff raction region of studied feldspars obtained by the classical method. the sample name is on the right side of the pattern’s segment. peaks are assigned according to the following reference data: quartz (q) – jcpds 33-1161; low albite (la) – jcpds 20-0554; albite (a) – jcpds 200548; low microcline (lm), intermediate microcline (im) and orthoclase (o) from borg & smith (1969). standard. powder patterns were recorded on the paper and the peak positions were determined manually. the potassium feldspar polymorph(s) have been identifi ed with the help of the jcpds database. unitcell software (holland & redfern, 1997) was used for unit cell parameters calculation. (2) data for megacrysts were collected in 5–70° 2θ ranges on a siemens d5000 theta-theta diffractometer equipped with graphite secondary beam monochromator. conditions were: cukα1 radiation, 0.02° 2θ step size and 5 seconds counting time per step. the rietveld analyses were performed by the dbws-9006 pc program package (young et al., 1994). triclinicity and ordering were calculated for both type of patterns (classical and digital) i.e. for both type of samples (separeates and megacrysts). triclinicity was calculated using the formula ∆ = 12.5*[d(131)-d(13̄1)] of goldschmidt & laves (1954). degree of ordering was determined according to [110] method (kroll & ribbe, 1983) and ∆sm method (neves & godinho, 1995). lattice translations tr [110] = ½ (a2 + b2 + 2ab cosγ)1/2 and tr [11̄0] = ½ (a2 + b2 – 2ab cosγ)1/2 were used for graphical estimation of t1o values (kroll & ribbe, 1983) while the ordering index ∆sm = 15.32 − ∆2θ / 0.608 (neves & godinho, 1995) is applied for calculation the percentage of t1o sites occupied by al: σal(t1) = 45 ∆sm + 55. 4. results the powder diffraction patterns revealed that different polymorphs of feldspar are present in the rocks that differ both horvat et al.: x-ray study of potassium feldspars from diff erent granitoid types and gneisses of papuk mt. (slavonia, croatia) geologia croatica 157 by rock type and sampling locality. x-ray powder patterns revealed that monzogranites from rajčevica and pakra creeks (figs. 1 and 2), granitoids from brzaja creek and gneisses from djedovica quarry contain only low microcline and low albite. gneisses from brzaja creek, monzogranite from kišeljevac and šandrovac creeks and fi ne to medium-grained granitoid samples from pakra creek valley also contain orthoclase. porphyric and slightly porphyric granodiorites are typical of the pakra creek valley. orthoclase is ubiquitous in these samples. if microcline appears, it is intermediate microcline. the potassium feldspar polymorph in the ppm-9 gneiss sample (brzaja creek) is monoclinic orthoclase. rietveld refi nement for four feldspar megacrysts produced identical results in determination of feldspar polymorphs as the classical method, although small differences in δ values were present (table 1). observed and calculated diffraction patterns of one of the feldspar megacryst samples (2ppg-5) are shown in figure 3. triclinicity (δ) calculations showed that the majority of the potassium feldspars occurring in the papuk granitoids have values higher than 0.70 on the scale, where a microcline with maximum triclinicity has value of 1. the exception is the intermediate microcline modifi cation that occurs in granodiorites of the pakra creek valley with triclinicity around or < 0.50. the lowest value is characteristic for the porphyric granodiorite of pakra creek valley (δ=0.29). the highest values (δ >0.90) are obtained on gneisses (table 1). pairs of triclinicity values obtained by two methods, classical (1) and rietveld (2) are as follows: 0.81–0.96 for brzaja creek twomica monzogranite, 0.29–0.33 and 0.32–0.29 for pakra creek porphyric granodiorites and 0.70–0.72 for pakra creek twomica monzogranite (tab. 1 and fig. 2). table 2 presents unit cell parameters, t1o occupancies and ordering for separates as well as for four potassium feldspar megacrysts. feldspars from granitoids 2ppg-3, ppg-19 (pakra creek) and gneisses ppm-5 and ppm-9 (brzaja creek) have lattice parameters that conform to a monoclinic cell. two grains (patterns a and b) of the 2ppg-6 granitoid sample show initial splitting of peak at 29.79 and 29.75 2°θ (fig. 2). the splitting is not measurable so they are determined as orthoclase. feldspars from ppg-4, ppg-8, ppg-20, 2ppg32, 2ppg-33, heg-31 and ppg-12 granitoids have a0 between 8.56 to 8.59å, b0 from 12.92 to 13.01å and c0 in 7.20– 7.22å range, which correspond to the triclinic symmetry. feldspar of ppg-18 and previously mentioned 2ppg-32 and heg-31 samples shows a complicated {131} region with orthoclase and low microcline peaks. these peaks prove a presence of more than one potassium phase i.e. coexistence of pha ses having monoclinic and triclinic symmetries in various proportions within the same sample (table 2). overlapping of peaks on patterns (ppg-18, ppg-23 and pp-13/6 samples) meant that only a limited number of peaks could be used for calculation of unit cell parameters. consequently the results for these samples are doubtful (table 2, grey colour-coded samples). in contrast, feldspar from the 2ppg-5 sample shows intermediate microcline peaks, but those peaks are sharp with figure 3: observed and calculated diff raction pattern (plus signs and line, respectively) of 2ppg-5 sample feldspar megacryst. the lower curve shows the diff erence between the observed and calculated patterns. tick marks indicate the positions of the allowed refl ections of microcline (upper) and albite (lower). calculated triclinicity (δ) is shown in table 1 (last column). geologia croatica 64/2geologia croatica 158 fair intensity and they could be accurately read (figure 2). intermediate microcline of the 2ppg-5 sample have a0 = 8.56, b0 = 12.96 and c0 = 7.21å, with α slightly different from 90°, which also revealed triclinic symmetry (table 2). lattice translation tr[11̄0] and cell volume results (table 2) obtained from classically observed diffraction patterns gave an al distribution in the t1o site as follows; granitoids (ppg-4, ppg-8 and ppg-12) and gneiss from brzaja creek (ppm-3), gneiss in djedovica quarry (pp-13/1), granitoids from šandrovac (2ppg-32), rajčevica (2ppg-33) and kiše ljevac locality (heg-31) have high al content in the t1o site. it is higher than 0.90, in most cases close to 1 (table 2, figure 4). however, granitoids in the pakra creek valley (2ppg-5, 2ppg-6, ppg-24) have an al content around 0.60 in the t1o site. the exception is the ppg-20 pakra granitoid sample with 0.96 t1o occupancy value. lattice translation tr[11̄0] and cell volume results obtained from diffraction patterns calculated by rietveld refi nement, (table 2), showed that potassium feldspar from the brzaja creek granitoid (ppg-8r) has a high al content in the t1o site (0.98), while megacrysts from pakra creek porphyric granodiorites (2ppg-5r, ppg-24r, ppg-20r) have lower values, around 0.60 up to 0.84. comparison of the values obtained from the observed and calculated diffraction patterns showed that the results match in case of three samples (ppg-8, 2ppg-5 and ppg24). for the patterns of the ppg-20 sample there is an obvious discrepancy between the t1o values obtained by classical and rietveld refi nement methods (0.96 and 0.84, respectively). this cannot be explained as uncertainty in reading the peak positions (see figure 2), and is most probably the result of the small number of peaks that could be used for unit cell parameter calculations. ordering index ∆sm and σal in the t1 sites calculated according to neves & godinho (1995) are also shown in table 2. investigated potassium feldspars have ∆sm from 0.50 to 1 while σal(t1) range from 79% to 99%. according to the fact that the total al content of the t1 sites is 55% in table 2: unit cell parameters calculated with unitcell software (holland & redfern, 1997) for classically observed diff raction patterns and calculated by rietveld refi nement (signed by subscript r). lattice translations tr[11̄0], al content in the t1o site (according to kroll & ribbe, 1983 method), ordering index δsm and σal(t1) (according to neves & godinho, 1995) for investigated potassium feldspars from papuk mt. samples ppg-4 to heg-31 are granitoids, while samples ppm-3 to pp-13/6 are gneisses (see table 1). the (doubtful) results for samples where overlapping of peaks allowed unequivocal indexing of limited number of peaks are shown in grey. sample a0 (å) b0 (å) c0 (å) a(°) b(°) g(°) v (å3) tr[11̄0] (å) t1o dsm sal(t1) % ppg-4 8.577(5) 12.971(6) 7.220(3) 90.7(1) 115.87(6) 87.82(8) 722 (1) 7.6379 0.97 0.9 95 ppg-8 8.567(6) 12.95(1) 7.206(3) 90.71(6) 115.93(6) 87.74(6) 718(1) 7.6214 0.96 0.61 82 ppg-12 8.573(4) 13.01(1) 7.211(7) 90.55(8) 116.00(5) 87.83(7) 722(1) 7.6536 0.91 0.85 93 ppg-18 8.460(1) 12.776(5) 7.147(2) 90.56(4) 116.26(3) 87.88(4) 691(1) 7.5299 0.95 0.9 95 2ppg-3 8.574(7) 12.98(1) 7.21(1) 116.00(6) 721(1) 2ppg-4a 8.592(8) 12.98(1) 7.210(3) 90.02(9) 115.99(7) 89.36(9) 723(1) 7.7429 0.57 0.75 89 2ppg-5 8.568(8) 12.969(6) 7.210(3) 90.10(8) 115.90(6) 89.38(9) 720(1) 7.7309 0.59 0.73 88 2ppg-6a 8.599(5) 12.953(4) 7.219(3) 90.01(4) 116.41(6) 89.64(5) 720(1) 7.7427 0.56 0.53 79 2ppg-6b 8.577(6) 12.972(8) 7.21(1) 90.18(8) 115.93(6) 89.52(8) 721(1) 7.7515 0.53 0.53 79 ppg-19 8.594(6) 12.976(6) 7.209(5) 116.04(6) 722(1) ppg-20 8.582(4) 12.924(4) 7.223(3) 90.40(4) 116.07(5) 87.90(4) 719(1) 7.6248 0.96 0.93 97 ppg-23 8.505(4) 12.866(2) 7.145(1) 90.58(2) 115.78(2) 88.42(3) 703(1) 7.6130 0.79 0.83 92 ppg-24 8.575(2) 12.974(2) 7.205(1) 90.285(3) 116.14(2) 89.14(2) 719(1) 7.7220 0.6 0.71 87 2ppg-32 8.575(8) 12.958(7) 7.208(3) 90.751(6) 115.92(5) 87.74(5) 719(1) 7.6269 0.99 0.73 88 2ppg-33 8.572(4) 12.967(6) 7.216(5) 90.69(7) 115.80(6) 87.96(7) 722(1) 7.6438 0.95 0.71 87 heg-31 8.591(6) 12.966(8) 7.221(5) 90.59(7) 115.91(7) 87.80(6) 721(1) 7.6382 0.98 0.85 93 ppm-3 8.595(7) 12.957(6) 7.217(2) 90.59(4) 115.94(3) 87.78(5) 722(1) 7.6343 0.97 0.98 99 ppm-5 8.59(1) 13.02(1) 7.20(1) 115.95(9) 724(1) ppm-9 8.552(8) 12.95(1) 7.179(8) 116.06(8) 714(1) pp-13/1 8.571(9) 12.96(2) 7.212(8) 90.716(9) 115.89(9) 87.66(4) 720(1) 7.6216 0.99 0.99 99 pp-13/6 8.571(4) 12.942(7) 7.202(3) 90.842(7) 115.85(5) 87.53(6) 718(1) 7.6059 out of diagram 0.81 91 ppg-8r 8.577 12.979 7.225 90.653 115.96 87.71 722(1) 7.6341 0.99 0.94 97 2ppg-5r 8.571 12.965 7.206 90.213 115.98 89.21 720(1) 7.7217 0.61 0.67 85 ppg-20r 8.577 12.966 7.212 90.520 115.98 88.25 720(1) 7.6629 0.84 0.83 92 ppg-24r 8.572 12.967 7.205 90.262 115.98 89.14 720(1) 7.7181 0.62 0.70 86 horvat et al.: x-ray study of potassium feldspars from diff erent granitoid types and gneisses of papuk mt. (slavonia, croatia) geologia croatica 159 high sanidine and 100% in low microcline (kroll & ribbe, 1987) these estimated values correlate well with those determined from unit cell parameters. 5. discussion polymorphic modifi cations of alkali feldspars are the result of the al-si distribution in the crystal structure. the way in which the al content changes in each tetrahedral site (t1o, t1m, t2o and t2m), from the most disordered (sanidine), to the most ordered state (high triclinic/low microcline), is called the ordering path in alkali feldspars (smith, 1974; grif fen, 1992). ordering is a two-step phenomenon: (1) the migration of al from the t2 to t1 sites and (2) al migration from t1m, t2o and t2m to the t1o site (stewart & wright, 1974). if the feldspar is monoclinic, the probability of fi nding al at the t1o and t1m sites is equal (t1o = t1m). if the crystal is completely ordered, in the unit cell there will be 1.0 al + 3.0 si along b (kroll & ribbe, 1983). during the ordering process, t-o bond lengths vary and o-t-o and t-o-t bond angles are affected (kroll, 1973). the t-o bond lengths refl ect al occupancy; therefore the al occupancy can be estimated by calculating t-o bond lengths. an increase in aluminium occupancy causes an increase in the mean bond length, whereas an increase in silicon occupancy causes their decrease (kroll, 1973). during al-si ordering, triclinic feldspars expand along [110] and contract along [11̄0]. the translation tr[110] estimates t1o+t2o+t2m and tr [11̄0] estimates t1m+t2o+t2m. because the same amount of al and si atoms is present in the unit cell regardless of the structural state (griffen, 1992), unit cell volume (v) should be a function of composition but not of structural state. if tr[11̄0] is plotted versus cell volume (v), t1o can be estimated directly from the diagram of kroll figure 4: plots of tr [11̄0] against v [å3] showing the estimated t1o values for investigated feldspars. values for end members are from kroll & ribbe (1987). dots are from kroll et al. (1986); crosses from wright & stewart (1968). the kink at v = 695å3 (or~35) is due to the triclinic/monoclinic symmetry change. geologia croatica 64/2geologia croatica 160 & ribbe (1983). therefore the [110] method can be used for determining the (al-si) distributions among the non-equivalent tetrahedral sites. if ordering proceeds as far as possible, all of the aluminium is found in t1o, therefore t1o=1.0; t1m=t2o=t2m=0.0 and alkali feldspar is referred to as maximum (or low) microcline. according to the results presented in table 2 studied granitoids from brzaja, kišeljevac, šandrovac and rajčevica creek valleys and gneisses in djedovica quarry and one gneiss sample from brzaja creek valley contain highly ordered potassium feldspar, because most of the al atoms are found in the t1o site (fig. 4). these potassium feldspars have high triclinicity (0.81–0.99; table 1) and correspond to the highly ordered microcline (low microcline) (smith, 1974; griffen, 1992). al occupancy in the t1o site of pakra creek valley granitoid feldspars are between 0.53 and 0.62 (table 2, fig. 4); their triclinicity is low (around 0.30 or even 0.0) (table 1) and they correspond to intermediate microcline or orthoclase. brzaja creek valley gneiss feldspars, excluding low microcline in ppm-3 sample, with triclinicity value δ = 0 revealed to be orthoclase. results obtained by goldschmidt & laves (1954), kroll & ribbe (1983) and neves & godinho (1995) methods indicate variation in the structural state, from orthoclase, intermediate microcline to highly ordered microcline in the investigated rock samples. high triclinicity values of feldspars from granitoid and gneiss samples from pa puk mt. (slavonia, croatia) are in accordance with high al contents in the t1o site and their fully ordered state indicate a slow(er) cooling-rate. low triclinicity values, al content in t1o site of around 0.60, and an ordering index smaller than 0.80 can be interpreted as a result of relatively fast(er) cooling which allowed the existence of less ordered potassium feldspar. classical and diffraction patterns calculated by the rietveld refi nement method gave comparable results. obtaining correct cell parameters depends primarily upon accurate measurement of the peak positions and the correct indexing of x-ray powder patterns. 6. concluding remarks according to x-ray powder diffraction results, the porphyric potassium feldspar in biotite-granodiorites and monzogranites is orthoclase or intermediate microcline, while two-mica monzogranite contains maximum microcline (low microcline). orthoclase and intermediate microcline are typical for pakra creek valley granodiorites, while highly ordered microcline (low microcline) characterises monzogranite rock types in the pakra, šandrovac, rajčevica, kišeljevac and brzaja creek valleys. gneisses associated with granites contain low microcline and orthoclase (brzaja creek valley), and low microcline (djedovica quarry). some granitoid and gneiss samples only contain orthoclase. intermediate microcline or orthoclase from biotite-granodiorites and monzogranites compared with highly ordered, structured, potassium feldspars from two-mica monzogranites indicate differences in the rate of cooling, as the most important factor controlling the ordering of potassium feldspars. the two-mica granitoids as host rocks, have a eutectic composition and peraluminous character. they are syn-collision granitoids according to horvat (2004), horvat & buda (2004) and their overall triclinic symmetry implies a slow cooling-rate and higher degree of order with the aid of fl uid activity or deformation in the case of the gneiss (brown & parsons, 1989). porphyric biotite-granodiorite and monzogranite have a peraluminous-metaluminous character and were probably formed post-collision in an uplifted environment (horvat, 2004; horvat & buda, 2004). they were emplaced at shallower levels in the crust; thus cooling was relatively fast which prevented the symmetry inversion and retarded ordering. rapid cooling seems to be the most probable explanation for preservation of monoclinic structures and the moderate degree of al-si ordering of potassium feldspars in these rocks. estimation of three different methods for k-feldspar characterization: triclinicity calculations according to goldschmidt & laves (1954), structural state determination by the method of kroll & ribbe (1983) and the ordering index method introduced by godinho & jaleco (1973) once again proved the very good correlation of results obtained by these methods. this fact gives greater weight to conclusions arising from them i.e. makes them more reliable. simple and relatively fast standard methods for potassium feldspar determination and description produced results that correlate well with those obtained by more accurate but more time-consuming methods. acknowledgment this study was carried out in the department of mineralogy, eötvös loránd university, budapest and was supported by the hungarian ministry of education through the ph.d. scho larship and hungarian national research fund (otka project no. k 67787). the authors are very grateful to judit király-tóth (department of mineralogy, eötvös loránd university budapest) for the help with recording analogue x-ray powder diffraction patterns and ivo suša (croatian geological survey, zagreb) for help with drawings. we are particularly grateful to julie robson (ocp consulting, scot land) for language editing. the authors acknowledge corrections and suggestions referred by galiba sijarić (faculty of science, university of sarajevo) and to an anonymous reviewer which led to the reorganization of the paper and its improvement. references balen, d., horváth, p., tomljenović, b., finger, f., humer, b., pamić, j. & árkai, p. (2006): a record of pre-variscan barrovian regional metamorphism in the eastern part of the slavonian mountains (ne croatia).– mineral. petrol., 87, 143–162. doi: 10.1007/s00710-006-0120-1 biševac, v., balen, d., tibljaš, d. & španić, d. (2009): preliminary results on degree of thermal alteration recorded on the eastern part of mt. papuk, slavonia, croatia.– geol. croat., 62/1, 63– 72. horvat et al.: x-ray study of potassium feldspars from diff erent granitoid types and gneisses of papuk mt. (slavonia, croatia) geologia croatica 161 biševac, v., balogh, k., balen, d. & tibljaš, d (2010): eoalpine (cretaceous) very lowto low-grade metamorphism recorded on illite-muscovite rich fraction from south tisia (eastern mt. papuk, croatia).– geol. carpath., 61/6, 469–481. doi: 10.2478/v10096-010 0029-9 borg, i.y. & smith, d.k. (1969): calculated x-ray powder patterns for silicate minerals.– geological society of america, inc. memoir, 122, 896 p. brown, g. (1961): the x-ray identifi cation and crystal structures of clay minerals.− mineralogical society, london, 544 p. brown, w.l. & parsons, i. (1989): alkali feldspars: ordering rates, phase transformations and behaviour diagrams for igneous rocks.– mineral. mag., 53, 25–42. goldschmidt, j.r. & laves, f. (1954): the microcline-sanidine stability relations.– geochim. cosmochim. ac., 5, 1–19. godinho, m.m. & jaleco, j.m.p. (1973): feldspatos potássicos dos granitóides da região de castro daire (viseu, portugal). i. estado estrutural.− memórias e notícias, publ. mus. lab. mineral. geol. univ. coimbra, 76, 44–71. griffen, d.t. (1992): silicate crystal chemistry.− oxford university press, oxford, 442 p. grim, r.e., bray, r.h. & bradley, r.f. (1937): mica in argillaceous sediments.− am. mineral., 22, 813–829. holland, t.j.b. &. redfern, s.a.t (1997): unit cell refi nement from powder diffraction data: the use of regression diagnostics.– mineral. mag., 61, 65–77. horvat, m. (2004): geochemistry and petrology of granitoids of papuk and psunj mts. (slavonia, croatia).– unpubl. phd thesis, university of budapest, (133+108) p. horvat, m. & buda, gy. (2004): geochemistry and petrology of some granitoids from papuk and psunj slavonian mountains (croatia).– acta miner. petrograph., 45/1, 93–100. horvat, m, kovács kis, v. & dódony, i. (2002): crystallization path of k-feldspar megacrysts from mt. papuk, croatia.– in: michalik, j., šimon, l. & vozar, j. (eds): proceedings of the xviith congres of carpathian-balkan geological association, bratislava, september 1-4, 2002. geol. carpath., 53, 189–190. horváth, p., balen, d., finger, f., tomljenović, b. & krenn, e. (2010): contrasting p-t-t paths from the basement of the tisia unit (slavonian mts., ne croatia): application of quantitative phase diagrams and monazite age dating.– lithos, 117, 269– 282. doi: 10.1016/j.lithos.2010.03.004 jamičić, d. (1983): strukturni sklop metamorfnih stijena krndije i južnih padina papuka [structural pattern of the metamorphosed rocks of the mt. krndija and the southern part of mt. papuk – in croatian].– geol. vjesnik, 36, 51–72. jamičić, d. (1988): strukturni sklop slavonskih planina (sjeverni psunj, papuk, krndija) [structural pattern of the slavonian mountains (nort hern psunj, papuk, and krndija) – in croatian].– unpubl. phd thesis, university of zagreb, 152 p. jamičić, d. (1989): osnovna geološka karta sfrj 1:100000, list daruvar, l33-95. [basic geological map of sfry, 1:100000, daruvar sheet – in croatian].– geološki zavod zagreb, savezni geološki zavod beograd. jamičić, d. (2001): main geological features of the slavonian mts. focused to the našice area.– matica hrvatska, našički zbornik, 6, 29–36. jamičić, d. & brkić, m. (1987): osnovna geološka karta sfrj 1:100000, list orahovica, l33-96 [basic geological map of sfry 1:100000, orahovica sheet – in croatian].– geološki zavod zagreb, savezni geološki zavod beograd. kovács kis, v., horvat, m. & dódony, i. (2004): microstructures in two alkali feldspar megacrysts from the papuk mt., croatia.– geol. croat., 57/2, 149–158. kroll, h. (1971): determination of al, si distribution in alkali feldspars from x–ray powder data.– neues jb. miner. monat., 91–94. kroll, h. (1973): estimation of the al, si distribution of feldspars from the lattice translations tr 110 and tr 11̄0. i. alkali feldspars.– contrib. min. pet. 39, 141–156. kroll, h. (1980): estimation of the al, si distribution of feldspars from lattice translations tr 110 and tr 11̄0. revised diagrams.– neues jb. miner. monat., 31–36. kroll, h. & ribbe, p.h. (1983): lattice parameters, composition and al, si order in alkali feldspars.– in: ribbe, p.h. (ed.): feldspar mineralogy, 2nd ed. rev. mineral. 2, 57–99. kroll, h. & ribbe, p.h. (1987): determining (al-si) distribution and strain in alkali feldspars using lattice parametres and diffractionpeak positions: a review.– am. mineral., 72, 491– 506. kroll, h., schmiemann, i. & von cölln, g. (1986): feldspar solid solutions.am. mineral., 71, 1–16. neves, l.j.p.f. & godinho, m.m. (1995): estimação expedita do ordenamento al-si do feldspato potássico-uma reapreciação.− memórias e notícias, publ. dep. ciências da terra e do mus. lab. mineral. geol. univ. coimbra, 120, 15−24. pamić, j. & lanphere, m. (1991): hercinske granitne i metamorfne stijene papuka, psunja, krndije i okolne podloge panonskog bazena u slavoniji (sjeverna hrvatska) [hercynian granites and metamorphic rocks from the mts. papuk, psunj, krdnija and the surrounding basement of the pannonian basin in slavonija (northern croatia, yugoslavia) – in croatian].– geologija, 34, 81–253. pamić, j., lanphere, m. & mckee, e. (1988): radiometric ages of metamorphic and associated igneous rocks of the slavonian mts. in the southern part of the pannonian basin, yugoslavia.– acta geologica, 18/2, 13-39. pamić, j., lanphere, m. & belak, m. (1996): hercynian i-type and s-type granitoids from the slavonian mountains (southern pannonian basin, northern croatia).− neues jb. miner. abh. 171/2, 155−186. raffaelli, p. (1964): metamorfi zam paleozojskih pelitskih škriljaca u području ravne gore [metamorphism of paleozoic politic schists of ravna gora – in croatian].– geol. vjesnik, zagreb, 18/1, 61–111. schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine-carpathian-dinaridic orogenic system: correlation and evolution of tectonic units.− swiss j. sci. 101, 139−183. doi: 10.1007/s00015-008-1247-3 shirozu, h. (1958): x-ray patterns and cell dimensions of chlorites.− mineral. journal, 2, 209–223. slovenec, d. (1976): izmjene biotita u pegmatitu iz potoka brzaje na papuku u uvjetima površinskog trošenja [weathering of biotite in pegmatite from the canyon of the brzaja stream in the papuk moun tain (north croatia) – in croatian].− geol. vjesnik, 29, 243–267. slovenec, d. (1978): mogućnost korištenja biotita kao indikatora geneze granitno-metamorfnih stijena papuka [on the possible utilization of biotite as a genetic indicator in the papuk granite-metamorphic rocks (north croatia) – in croatian].– geol. vjesnik zagreb, 30/2, 351–357. slovenec, d. (1982): kemijski sastav biotita, granata i amfi bola kao pokazatelj temperature formiranja granitno-metamorfnih stijena papuka [chemical composition of biotites, garnets and amphiboles as an indicator of the formation temperature of granite-metamorphic rocks of the papuk mountain – in croatian].– geol. vjesnik zagreb, 35, 133–152. geologia croatica 64/2geologia croatica 162 slovenec, d. (1988): transformacija biotita u klorit u granitno-metamorfnih stijena papuka [the alteration of biotite to chlorite in granito-metamorphic rocks from the mt. papuk – in croatian].– geol. vjesnik, 41, 87–98. smith, j.v. (1974): feldspar minerals, vol. i. crystal structure and physical properties.– springer, berlin, 627 p. stewart, d.b. & wright, t.l. (1974): al/si order and symmetry of natural alkali feldspars and the relationship of strained cell parameters to bulk composition.– b. soc. fr. mineral. cr., 97, 356–377. tajder, m. (1957): petrografsko istraživanje zapadnog dijela papuka [petrographic investigation of the western part of the papuk mt. – in croatian].– ljetopis jazu, 62, 316–323. tajder, m. (1969): magmatizam i metamorfi zam planinskog područja papuk-psunj [magmatism and metamorphism of the papuk-psunj mountains – in croatian].– geol. vjesnik, 22, 469–476. vragović, m. (1965): graniti i gnajsi papuka [granites and gneisses of the papuk mountain – in croatian].– unpubl. phd thesis, university of zagreb, 222 p. young, r.a., sakthivel, a., moss, t.s. & paiva-santos, c.o. (1994): dbws software: rietveld analysis of x-ray and neutron powder diffraction patterns.– users guide. wright, t.l. & stewart, d.b. (1968): x-ray and optical study of alkali feldspar: i. determination of composition and structural state from refi ned unit-cell parameters and 2v1.− am. mineral., 53, 39–86. manuscript received november 04, 2010 revised manuscript accepted april 20, 2011 available online june 09, 2011 ab stra ct radiolarian assemblages of late cretaceous age were studied in a carbonate-clastic section from the cretaceous sedimentary cover that unconformably overlies triassic sediments of the jadar block. according to the identifi ed radiolarian associations, the studied limestone is of santonian age. considering the fact that these sediments belong to a broadly defi ned turonian-senonian geologic map unit, the obtained data are important for further more detailed biostratigraphic assignment of late cretaceous rocks in western serbia. moreover, the obtained data are very important for interregional correlations. keywords: upper cretaceous, radiolaria, jadar block, vardar zone western belt, western serbia  geologia croatica 67/3 163–170 4 fig. 1 tab. 2 pls. zagreb 2014 geologia croaticageologia croatica new data on the age of an upper cretaceous clastic-carbonate succession in brežđe (western serbia)  nevenka đerić and nataša gerzina faculty of mining and geology, university of belgrade, đušina 7, 11000 beograd, serbia; (nevenka.djeric@rgf.bg.ac.rs) doi: 10.4154/gc.2014.12 1. introduction brežđe village is situated in western serbia, at the foothills of the maljen mountain. the geological setting of the area is extremely complicated, considering the fact that this is a contact zone between the continental jadar block and the western vardar ophiolites (figs. 1, 2). both units are overlain by transgressive cretaceous sediments. in the wider studied area, cretaceous sedimentation begins with the albian cenomanian transgressive sediments (filipović et al., 1978). terrigenous-carbonate and carbonate sedimentation continued to the end of the upper santonian (bragina et al., 2014) or campanian (gajić et al., 2011), while the overlying fl ysch sediments were deposited during the campanian-maastrichtian (filipović et al., 1978). according to bivalve species (marković & anđelko vić, 1953) and the identifi ed fossil foraminifers (fi lipović et al., 1978), the age of the studied sediments in the wider surroundings of brežđe was determined as senonian, without any further division. on the geologic map of serbia (filipović et al., 1977), these sediments are not even separated from turonian sediments, but are together marked as a single unit of turonian-senonian age. during the last few years, however, radiolarian investigations have been focused on the struganik locality in the vicinity of brežđe village. these investigations enabled a more detailed biostratigraphic assignment of the rocks that belong to the turonian-senonian map unit. the lowermost part of the clastic-carbonate succession was assigned an early senonian age (djerić et al., 2009). further investigations enabled a more precise age determination (early santonian) of these sediments, while the radiolarian associations from the overlying beds indicate a santonian age (bragina et al., 2014). the data presented in this paper will enable comparison with similar rocks in the wider surroundings, which should be an important contribution to better understanding of geology of western serbia. 2. geological setting the studied locality is situated in western serbia, 17 km southeast of valjevo and 7 km south of mionica, along the struganik-brežđe road (gps n44°11’30’’, e20°04’16.4’’) (figs. 1, 2). the investigated area is characterized by extremely complex geology. on the geologic map of western and southgeologia croatica 67/3geologia croatica 164 western serbia, there are two conspicuous, more or less parallel, nw-se oriented belts of ophiolitic mélange overlain by large ultramafic massifs. the southwestern belt is known as the dinaridic ophiolite belt (pamić et al., 2002; karamata, 2006), the central dinaridic ophiolite belt (lu gović et al., 1991) or the ophiolite belt (dimitrijević, 1997). the ophiolite belt in the northeast is referred to as the vardar zone western belt (karamata, 2006), but also referred to under a variety of names such as the inner dinaridic ophiolite belt (lugović et al., 1991), the external vardar subzone (dimitrijević, 1997, 2001) or simply the vardar zone (pamić et al., 2002). there are opinions that ophiolites in these two belts resulted from obduction of just one ocean (pamić, 1998; pamić et al., 2000; csontos et al., 2003; schmid et al., 2008). occurrence of ophiolites in two rather than only one belt is due to out-of-sequence thrusting and later nappe refolding during cretaceous and tertiary orogenic phases (csontos et al., 2003). a majority of serbian geologists, however, are of the opinion that these ophiolitic belts represent remnants of two different oceanic realms separated by the drina-ivanjica continental block (dimitrijević & dimi trijević, 1973; robertson & karamata, 1994; karamata et al. 1999, dimitrijević, 2001). another continental unit, i.e. the jadar block, is situated north of the vardar zone western belt. it is considered (by the majority of serbian geologists) to be either an integral part of the vardar zone (dimitrijević, 1997) or an exotic figure 1: tectonic sketch of the dinarides, modified after schmid et al. (2008). figure 2: a simplified and modified geological map of the wider surroundings of the investigated area, based on the geological map of sfr yugoslavia 1:500 000 (savezni geološki zavod, 1970); vzwb – vardar zone western belt, jb – jadar block, die – drina-ivanjica element đerić and gerzina: new data on the age of an upper cretaceous clastic-carbonate succession in brežđe (western serbia) geologia croatica 165 body pushed into the vardar zone in the late cretaceous (karamata et al., 1994). the present-day tectonic contact between the drinaivanjica and the jadar block (fig. 2) is very steep and with a strong dextral strike-slip component (gerzina & csontos, 2003). in the literature, this contact is referred to as the “zvornik suture” (dimitrijević, 1997) that is supposed to mark the ophiolitic suture between the drina-ivanjica and jadar blocks (karamata, 2006). according to schmid et al. (2008), the “zvornik suture” simply represents the northwestern continuation of the long belt of senonian flysch, which marks the tectonic boundary between the drinaivanjica and the jadar-kopaonik thrust sheets. according to recent interpretations, the drina-ivanjica and jadar units structurally underlie neotethyan ophiolites of jurassic age that were obducted onto the adria margin during the late jurassic (schmid et al., 2008). however, the original position of the jadar block below the ophiolitic mélange is visible only in the area of takovo. in other places, however, the jadar block seems to be thrust over the mélange and ophiolites (south of valjevo) and partly over the late cretaceous sediments (in the area of poćuta). such a position of the jadar block is probably a consequence of the postsenonian (paleogene?) collision-related thrusting and folding (gerzina & csontos, 2003; csontos et al., 2004). the late jurassic to early cretaceous transgressive phase, characterized predominantly by alluvial to neritic sedimentation, started after the obduction and the subsequent erosion in the dinaridic-hellenic belt (pamić et al., 1998; pamić & hrvatović, 2000; schmid et al., 2008). in western serbia, however, these sediments are absent, possibly due to early to mid-cretaceous collisional processes (schmid et al., 2008). in the wider research area, both triassic sediments of the jadar block and jurassic rocks of oceanic origin that belong to the vardar zone are both unconformably overlain by transgressive albian-cenomanian clas tic sediments containing redeposited ophiolite fragments. terrigenous-carbonate and carbonate sedimentation follow ed through the cretaceous until the campanian when flysch sedimentation began (filipović et al., 1978). 3. materials and methods the described radiolarian assemblages originate from a section in brežđe village (fig. 3). four samples, three of which pro duced positive results (br 1/1, br 1/2 and br 1/3) were taken from marly limestone. the samples were treated with 7–15% acetic acid (ch3cooh), utilizing the standard methods. the residues of the acid treatment, which yielded a well preserved fauna, were studied for biostratigraphic purposes. a sem microscope jeol jsm-6610lv sem at the faculty of mining and geology, university of belgrade was utilized for precise identification of the radiolarians shown in pls. 1–2. table 1: distribution of radiolarian taxa in the studied samples. species samples br1/1 br1/2 br1/3 alievium gallowayi (white) • • alievium sp. • • amphipyndax stocki (cambell & clark) cf. cf. amphipyndax sp. • • cryptamphorella ? sp. • dictyomitra formosa squinabol • • • dictyomitra koslovae foreman • • • dictyomitra multicostata zittel cf. dictyomitra sp. • • patellula euessceei empson-morin cf. • patellula helios (squinabol) sensu o’dogherty cf. patellula sp. • • • praeconocaryomma universa pessagno cf. cf. xitus asymbatos (foreman) • xitus sp. • figure 3: a simplified geological profile in brežđe village. geologia croatica 67/3geologia croatica 166 plate i santonian radiolarians from the brežđe section, western serbia 1–3 – alievium gallowayi (white). 4, 5 – alievium sp. 6 – patellula sp. cf. p. helios (squinabol) sensu o’dogherty 7, 8 – patellula sp. 9, 10 – patellula euessceei empson-morin 11, 12 – patellula sp. 13, 14, 15 – praeconocaryomma sp. cf. p. universa pessagno. specimens illustrated in figs. 1, 2, 4, 7-9, 13, 14 originate from sample br 1/1; specimens in figs. 6, 10 are from sample br 1/2; specimens in figs. 3, 5, 11, 12, 15 are from sample br 1/3. scale bar length for all images is 50μm. đerić and gerzina: new data on the age of an upper cretaceous clastic-carbonate succession in brežđe (western serbia) geologia croatica 167 plate ii santonian radiolarians from the brežđe section, western serbia 1, 2 – amphipyndax sp. 3, 4 – amphipyndax sp. cf. a. stocki (campbell & clark) 5, 6 – xitus asymbatos (foreman) 7-18 – dictyomitra formosa squinabol 19-28 – dictyomitra koslovae foreman 29 – dictyomitra sp. 30 – cryptamphorella ? sp. specimens illustrated in figs. 1-3, 5-10, 18-22, 29, 30 originate from sample br 1/1; specimens in figs. 11-13, 23-25 are from sample br 1/2; specimens in figs. 4, 14-17, 26-28 are from sample br 1/3. scale bar length for images 1-4, 7-24, 26-30 is 50μm; for images 5, 6, 25 is 100μm. geologia croatica 67/3geologia croatica 168 the micropaleontological material is housed at the faculty of mining and geology in belgrade (registration numbers br 1/1, br 1/2 and br 1/3). 4. section description and biostratigraphy in the wider area of brežđe, marković & anđelković (1953) distinguished albian-cenomanian, cenomanian, turonian and senonian sediments. according to filipović et al. (1978), turonian sediments are represented by detrital limesto ne with marlstone interlayers, reddish bedded silicified limestone, marly-sandy conglomeratic limestone and reddish marly claystone. senonian sediments are best exposed in struganik village. they are represented by a sequence predominantly made up of thin-bedded limestone, clayey limestone and marlstone (the so-called struganik limestone). chert concretions are present throughout the sequence. based on the identified radiolarian as sociation, the lower senonian age of grayish clay intercalations in limestone of the struganik quarry was determined by djerić et al. (2009), while bragina et al. (2014) distinguished several bed-ranked units, ranging from the lower to the upper santonian, in a carbonate-flyschoid section near struganik village. the profile in brežđe village (fig. 3) starts with strongly sheared serpentinite in the footwall of slightly metamorphic triassic platform carbonates. the footwall of the serpentinite is not visible along the profile but, according to the observations in the immediate surroundings, serpentinite is in a tectonic contact with the underlying ophiolitic mélange. this original tectonic sandwich was possibly folded and certainly slightly metamorphosed and cleaved prior to the senonian and also strongly folded after the senonian (gerzina & csontos, 2003). the triassic carbonates are pre served in synforms, while the serpentinite forms the cores of antiforms. finally, the whole tectonic assemblage is unconformably overlain by an albian-cenomanian shaley, mar ly and carbonate succession grading to senonian, which has a shallowing-upward tendency (fig. 4). the original trans gressive relationships are disturbed by a steep-dipping fault along which triassic limestone is in contact with late figure 4: a generalized columnar section of the cretaceous in the studied area. the inset to the right shows the column interval studied for radiolarians, with the sample locations indicated. đerić and gerzina: new data on the age of an upper cretaceous clastic-carbonate succession in brežđe (western serbia) geologia croatica 169 cretaceous marlstone. the section terminates with shallowmarine carbonates. four samples were taken for micropaleontological investigations from gray-yellowish limestone, about 10 m thick at the brežđe section (fig. 4). associations of late cretaceous radiolarians are identified from three positive samples (table 1). all three samples are characterized by the common presence of dictyomitra formosa squinabol and dictyomitra koslovae foreman. the species dictyomitra formosa squinabol is distributed from the albian to the lower campanian (schaaf, 1985; bandini et al., 2006). dictyomitra koslovae foreman is characteristic of the campanian and the lower maastrichtian oceanic sediments (sanfilippo and riedel, 1985). it has also recently been reported from the santonian rocks (korchagin et al., 2012, bragina et al., 2014). samples br 1/1 and br 1/3 also contain the species alievium gallowayi (white), which is the index species of the synonymous santonian zone of california (pessagno, 1976). it should be noted that the joint occurrence of radiolarian species dictyomitra koslovae and alievium gallowayi is also known from santonian strata of the crimean mountains (korchagin et al., 2012) and struganik village in west serbia (bragina et al., 2014). the radiolarian association from sample br 1/1 also con tains cryptamphorella macropora dumitrica which, according to the available published data, had its last appearance in the campanian (dumitrica, 1970; empsonmo rin, 1984; urquhart, 1994), while the radiolarian assemblage in sample br 1/3 contains pseudoaulophacus lenticulatus (white) (lad in the campanian; pessagno, 1976; urquhart, 1994). in summary, the samples are certainly santonian in age, but a more precise dating is difficult to establish with the existing zonations. beside the radiolarians, the microfauna is surprisingly rich in sponge spicules. notable amounts of sponge spicule fragments together with abundant radiolarians are conspicuous features in all the three studied samples. monaxones predominate, but hexactines are frequent as well. a significant amount of sponge spicules together with abundant radiolarians in the studied samples indicate a relatively proximal slope environment (kiessling, 1996). 5. discussion and conclusions after the late jurassic obduction and subsequent erosion in the dinaridic-hellenic belt, cretaceous synorogenic basins were formed and filled with clastic material composed of variable amounts of ophiolitic, terrigenous and carbonate detritus (lužar-oberiter et al., 2012). therefore, the obducted ophiolitic sheets of the dinarides are in many places unconformably overlain with late jurassic to early cretaceous shallow and/or deep marine sediments (pamić et al., 1998; pamić & hrvatović, 2000; schmid et al., 2008). in western serbia, however, early cretaceous sediments are missing and transgression did not start prior to the end of the lower cretaceous, thus both triassic sediments of the passive margin of the adria and jurassic rocks of oceanic origin are both unconformably overlain by a transgressive succession that starts with albian-cenomanian clastites. the studied sediments of santonian age are parts of this late cretaceous terrigenous-carbonate sequence which was continuously deposited until the campanian, when flysch sedimentation began and the so-called ljig flysch of campanian-maastrichtian age was formed. in order to enable more detailed stratigraphic division of the turonian-senonian terrigenous-carbonate sequence in western serbia, late cretaceous radiolarians have been extensively studied during the last five years (djerić et al., 2009; bragina et al., 2014). according to lithostratigraphic correlation and the identified radiolarian association, the studied limestone corresponds to the struganik limestone which originated on the continental slope, in a relatively proximal slope environment which is indicated by a significant amount of sponge spicules together with abundant radiolarians. the santonian age of the analyzed sediments is based on radiolarians. similar santonian radiolarian assemblages are known from deposits of the mt. ak-kaya, crimean mountains (korchagin et al., 2012) and from struganik village in western serbia (djerić et al., 2009; bragina et al., 2014). despite the almost identical stratigraphic relationships observed in the struganik and brežđe villages, the differences between the radiolarian associations are quite obvious. the brežđe radiolarian assemblages are far less taxonomically diverse in comparison with the radiolarian assemblages in struganik. moreover, the radiolarian association in brežđe is characterized by an absolute predomination of the species dictyomitra koslovae and dictyomitra formosa, which are also present also in the struganik associations, but in far lesser amounts. therefore, the radiolarian assemblages from struganik enabled more detailed biostratigraphic division of the host sediments (the lower santonian, uppermost lower santonian basal upper santonian and upper santonian; bragina et al., 2014). a santonian age is established for the studied radiolarians in brežđe, but the taxonomic composition of the assemblages does not allow any further division. geographically, the nearest similar radiolarian assemblages, although younger (campanian) are known from romania (vishnevskaya, 2001) and from southern cyprus, where they occur in the sedimentary cover of the troodos ophiolite and the associated mélange units (urquhart, 1994; bragina & bragin, 1995, 1996, 2006) as well as an assemblage from southern turkey from scaglia-type pelagic limestones of the upper antalya nappes (moix et al., 2009). acknowledgment the authors gratefully acknowledge špela goričan and one anonymous reviewer for their constructive comments and suggestions on the manuscript. the work was supported by the ministry of education, science and technological development of the republic of serbia (project no. 176015). geologia croatica 67/3geologia croatica 170 references bandini, a., baumgartner, o.p. & caron, m. (2006): turonian radiolarians from karnezeika, argolis peninsula, peloponnesus (greece).– eclogae geol. helv., 99/1, 1–20. bragina, l.g. & bragin, n.y. (1995): radiolarians and stratigraphy of the campanian maastrichtian deposits in southwestern cyprus.– stratigraphy and geological correlation, 3/2, 53–61. bragina, l.g. & bragin, n.y. (1996): stratigraphy and radiolarians from the type section of perapedhi formation (upper cretaceous of cyprus).– stratigraphy and geological correlation, 4, 246–253. bragina, l.g. & bragin, n.y. (2006): stratigraphy and radiolarians of upper cretaceous sedimentary cover of the arakapas ophiolite massif (cyprus).– stratigraphy and geological correlation, 14, 507–523. bragina, l.g., bragin, n.y., djerić, n. & gajić, v. (2014): late cretaceous radiolarians and age of flyschoid sediments in the struganik section (western serbia).– stratigraphy and geological correlation, 22/2, 202–218. csontos, l., gerzina, n., hrvatović, h., schmid, s. & tomlje nović, b. (2003): structure of the dinarides: a working model.– ann. univ. sci. budapest., sect. geol., 35, 143–144. dimitrijević, m.d. (1997): geology of yugoslavia.– geol. inst. gemini spec. publ., belgrade, 187 p. dimitrijević, m.d. (2001): dinarides and the vardar zone: a short review of the geology.– acta vulcanol., 13, 1–8. dimitrijević, m.n. & dimitrijević, m.d. (1973): olistostrome mélange in the yugoslavian dinarides and late mesozoic plate tectonics.– j. geol., 81/3, 328–340. dumitrică, p. (1970): cryptocephalic and cryptothoracic nasselaria in some mesozoic deposits of romania.– rev. roum. géol., géophys., géogr.– série de géologie, 14/1, 45–124. đerić n., gerzina n., gajić, v. & vasić, n. (2009): early senonian radiolarian microfauna and biostratigraphy from the western vardar zone (western serbia).– geologica carpatica, 60/1, 35–41. empson-morin, k. m. (1984): depth and latitude distribution of radiolaria in campanian (late cretaceous) tropical and subtropical oceans.– micropaleontology, 30/1, 87–115. filipović, i., pavlović, z., marković b., rodin, v., marković, o., gagić, n., antin, b. & milićević, m. (1977): osnovna geološka karta sfrj – list gornji milanovac 1:100000 [basic geologic map of former yugoslavia – sheet gornji milanovac 1: 100000].– savezni geološki zavod, beograd. filipović, i., marković, b., pavlović, z., rodin, v. & marko vić, o. (1978): osnovna geološka karta sfrj 1: 100000. tu mač za list gornji milanovac l34–137 [basic geologic map of former yugoslavia 1: 100000. explanatory booklet for the sheet gornji milanovac – in serbian].– savezni geološki zavod, beograd. gajić, v., matović v., vasić, n. & srećković-batoćanin, d. (2011): petrophysical and mechanical properties of the struganik limestone (vardar zone, western serbia).– ann. geol. penins. balk., 72, 87–100. gerzina, n. & csontos, l. (2003): deformation sequence in the vardar zone: surroundings of jadar block; serbia.– ann. univ. sci. budapestinensis, sect. geol., 35, 139–140. karamata, s. (2006): the geological development of the balkan peninsula related to the approach, collision and compression of gondwana and eurasian units.– in: robertson a.h.f. & mountrakis d. (eds.): tectonic development of the eastern medi terranean region.– geol. soc. london, spec. publ, 260, 155–178. karamata, s., knežević, v., memović, e. & popević, a. (1994): the evolution of the northern part of the vardar zone in mesozoic.– bull. geol. soc. greece, 30/2, 479–486. karamata, s., dimitrijević, m.n & dimitrijević, m.d. (1999): oceanic realms in the central part of the balkan peninsula dur ing the mesozoic.– slovak geol. mag., 5/3, 173–177. kiessling, w. (1996): facies characterization of mid-mesozoic deepwater sediments by quantitative analysis of siliceous microfaunas.– facies, 35, 231–274. korchagin, o.a., bragina, l.g. & bragin, n.yu. (2012): planktonic foraminifers and radiolarians from the coniacian-santonian deposits of the mt. ak-kaya, crimean mountains, ukraine.– stratigr. geol. correl., 20/1, 73–96. lugović, b., altherr, r., raczek, i., hofmann, a.w. & majer, v. (1991): geochemistry of peridotites and mafic igneous rocks from the central dinaric ophiolite belt, yugoslavia.– contr. mineral. petrology, 106, 201–216. marković, o. & anđelković, m. (1953): geološki sastav i tektonika šire okoline sela osečenice, brežđa i struganika – zapadna srbija [geological composition and tectonics of wider surroundings of villages osečenica, brežde and struganik (west serbia – in serbian].– zbornik radova san, 33, geol. inst, 5, 111–150. moix, p., goričan, š. & marcoux, j. (2009): first evidence of campanian radiolarians in turkey and implications for the tectonic setting of the upper antalya nappes.– cretaceous research, 30, 952–960. lužar-oberiter, b., dunkl, i., mikes, t., babić, lj. & von eynatten, h. (2012): provenance of cretaceous synorogenic sediments from the nw dinarides (croatia).– swiss j geosci., 105/3, 377–399. pamić, j. (1998): north dinaridic late cretaceous-paleogene subduction-related tectonostratigraphic units of southern tisia, croatia.– geol. carpathica, 49/5, 341–350. pamić, j. & hrvatović, h. (2000): dinaride ophiolite zone (doz).– in: pamić, j. & tomljenović, b. (eds.): pancardi 2000 fieldtrip guidebook. vijesti, 37/2, 60–68. pamić, j., gušić, i. & jelaska, v. (1998): geodynamic evolution of the central dinarides. tectonophysics, 297, 251–268, amsterdam. pamić, j., gušić, i. & jelaska, v. (2000): alpine tectonostratigraphic units and their geodynamic evolution.– proc. 2nd croatian geological congress (cavtat-dubrovnik, 17–20. 5. 2000), zagreb, 15–21. pamić, j., tomljenović, b. & balen, d. (2002): geodynamic and petrogenetic evolution of alpine ophiolites from the central and nw dinarides: an overview.– lithos, 65, 113–142. pessagno, e. a. (1976): radiolarian zonation and stratigraphy of upper cretaceous portion of the great valley sequence.– micropaleontol. spec. publ., 2/1, 96. robertson, a.h.f. & karamata, s. (1994): the role of subduction-accretion processes in the tectonic evolution of the mesozoic tethys in serbia.– tectonophysics, 234, 73–94. sanfilippo, a. & riedel, w.r. (1985): cretaceous radiolaria. plankton stratigraphy.– in: bolli h.m., saunders j.b. & perchnielsen k. (eds.): plankton stratigraphy.– cambridge university press, cambridge, 631–712. savezni geološki zavod (federal geological survey) (1970): geološka karta sfr jugoslavije, 1:500000 [geologic map of sfr yugoslavia, 1:500 000], beograd. schaaf, a. (1985): un nouveau canevas biochronologique du crétacé inférieur et moyen: les biozones à radiolaires.– sci. geol. bull., 38/2, 227–269. schmid, m.s., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine-carpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss j. geosci., 101/1, 139–183. urquhart, e. (1994): new data on the ranges of some cretaceous tethyan radiolaria.– comptes rendus de l’académie des sciences de paris, serie ii, 318, 1401–1407. vishnevskaya, v.s. (2001): jurassic to cretaceous radiolarian biostratigraphy of russia.– geos, moscow, 140, 1–376. manuscript received march 19, 2014 revised manuscript accepted september 16, 2014 available online october 31, 2014 2018 | 71/1 | 1–18 | 13 figs. | 1 tbl. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the bukovik-kadiica porphyry cu deposit is located in the eastern part of the republic of macedonia between the maleshevski mountains in the south and vlaina in the north (figs. 1 and 2). the deposit was first evaluated by the institute for exploration of mineral raw materials, skopje, and the sasa lead-zinc mines company in the 1960s. the main exploration efforts focused on ferricrete deposits that occur on the lower western slopes of bukovik hill near the belo brdo locality. these deposits were tested with shallow drill holes and several adits. geological studies of the bukovik-kadiica area have confirmed the complex geological setting (duzelkovski, 1960; bogoevski, 1965; stoja nović, 1969; kovacević et al., 1973; hadzi-petrusev, 1985; stojanov & aleksandrov, 1990; stojanov et al., 1995). the deposit occurs within the bukovik-kadiica exploration licence area formerly held by phelps dodge (2002– 2007) and recently held by the kadiica metal company (pehčevo). the exploration campaign carried out in 2011 and 2012 resulted in 16,500 m of drill cores and the discovery of 70 mt ore at a grade of 0.216% cu. the exploration campaign was accompanied by mineralogical and geochemical studies. the preliminary results have been given by tasev (2010), but here we present more detail descriptions of the mineralization, focusing on the fluid inclusions in mineralized quartz samples. the present study attempts to constrain the thermal evolution of the magmatic–hydrothermal system at the the bukovik-kadiica porphyry cu deposit using fluid inclusion analysis. evolution of ore-forming fluids in the bukovik-kadiica porphyry cu deposit, republic of macedonia goran tasev1,*, dalibor serafimovski2 and todor serafimovski1 1 university “goce delčev”, faculty of natural and technical sciences, goce delčev 89, 2000 štip, republic of macedonia; (corresponding author: goran.tasev@ugd.edu.mk) 2 university “goce delčev”, faculty of electrical engineering, goce delčev 89, 2000 štip, republic of macedonia doi: 10.4154/gc.2018.01 abstract the bukovik-kadiica mineralized system is hosted by tertiary dacitic and andesitic volcanic rocks which have intruded the basement of palaeozoic schists in the serbo-macedonian massif of eastern macedonia. the latest geological exploration has confirmed that this porphyry copper mineralization is characterized by a dominance of chalcocite and covellite with associated chalcopyrite, emplectite, and bornite, with the highest grades in a zone of supergene enrichment. silicification is the dominant alteration within the mineralized system, whilst zones of potassic, phyllic, argillic, propylitic, and advanced argillic alteration are also present. silicification and sulphide mineralization are located in stockworks in altered dacite and andesite breccia. dissolution of primary sulphides and chemical leaching are evident in the zones of oxidation, dominated by limonite breccia. the main copper mineralization has a vertical extent between 90 and 220 m. fluid inclusion studies of mineralized quartz veins have identified three separate groups of fluids: saline inclusions which homogenize at 326-501 °c and have a salinity of 32-45 wt% nacl equiv., vapourdominated inclusions which homogenize at 438-497 °c and have a salinity of 6-16 wt% nacl equiv., and more dilute, two-phase vapour–liquid inclusions that homogenize at 360-627 °c and have a salinity of 3-24 wt% nacl equiv. 2. regional geological setting the bukovik-kadiica deposit is located in the serbo-macedonian massif (smm), which was described by dimitrijevic (1959) as a separate geotectonic and lithostratigraphic unit in the southern part of the balkan peninsula. the smm is a crystalline basement complex boarded by the vardar zone to the west and by the rhodope massif to the east (figs. 1 and 2). the smm consists mainly of palaeozoic gneisses and schists (karamata, 1974a,b; kockel et al., 1975, grubić, 1980; du mur džanov et al., 2005), that have been intensely folded and faulted (burchfiel et al., 2008a; zagorchev et al., 2008; robertson et al., 2009). the smm represents a wedge of continental crust developed as part of the morava-rhodope zone at the margin of the tethys with eurasia. it is thrust westwards over the vardar zone and east wards (morava unit) over the strouma unit. precambrian (up per archaean to proterozoic) and vendian-cambrian complexes (dimitrijevic, 1995; zagorchev & milova novic, 2006) are unconformably overlain by lower palaeozoic, per mian, triassic, and upper cretaceous rocks. the precambrian ograzhdenian complex is composed of amphibolite-facies polymetamorphic and polydeformational rocks: gneisses, micaschists and amphibolites. it contains lenses of ultrabasic and basic rocks (serpentinites, harzburgites, lherzolites, norites), some of them transformed into eclogites. migmatites and metagranites are present, as well. recent data point toward tectonometamorphic amalgamation of very old (late archaean to early proterozoic) oceanic crust with precambrian continental crust, a major cadoarticle history: manuscript received june 12, 2017 revised manuscript accepted september 21, 2017 available online february 28, 2018 keywords: porphyry copper, fluid inclusions, hydrothermal alterations, bukovik-kadiica, republic of macedonia. g eo lo gi a c ro at ic a geologia croatica 71/12 mian tectonometamorphic event, ordovician metagranites, and late hercynian post-metamorphic granites (zagorchev et al., 2008; zagorchev et al., 2015). a vendian-cambrian green schist-facies complex (vlasina group, frolosh formation) has a thickness estimated between 1 and 4–5 km, and composition made of chlorite and actinolite schists, metasandstones, metaconglomerates, and metadiabases. metabasic rocks (gabbros) are also present. zircon data indicate an age of c. 560–570 ma (graf, 2001). boyanov et al. (1989) and dabovski et al. (2002) considered the alpine evolution of the region as a sequence of opening and closing of epicontinental basins with the formation of separate collisional orogens at the north-eastern side of the active plate (tethys) margin, whereas the tethys ocean itself evolved by the opening of several seaways between comparatively stable zones of similar lithologies. although the closure of the vardar ocean occurred in the late mid jurassic to late jurassic times, these isopic zones continued their evolution throughout the whole remaining part of the mesozoic and most of the cenozoic, with the youngest marine sediments of pliocene age (zagorchev et al., 2008; dumurdžanov et al., 2004) (fig. 1). numerous geological structures controlled emplacement of magmatic rocks and associated mineralization (janković & petković, 1974; janković et al., 1980; serafimovski, 1990). the tertiary volcanic activity along reactivated cenozoic structures (arsovski & ivanov, 1977; serafimovski, 1990, 1993), is usually accompanied by polymetallic mineralization of pb, zn, cu, au, ag, as, and sb type (janković et al., 1980; serafimovski et al., 1995; jankovic & serafimovski, 1997). major structures in the central parts of the smm have also been related to distinct and productive cu±au±ag±mo mineralizations (serafimovski et al., 2010). neotectonic sw–ne to e–w directed structures are not related to the mineralizations but are still seismically active (burchfiel et al., 2008b). 3. geological features the bukovik-kadiica mineralized system spatially belongs to the besna kobila-osogovo-thasos structural-metallogenetic zone (e.g., janković & petković, 1974; janković et al., 1980; serafimovski, 1990; serafimovski et al., 1995; jankovic & serafimovski, 1997). this metallogenetic zone has been formed along the eastern serbo-macedonian block, stretching parallel to the carpathian-balkan tectonic unit and western parts of the rhodope block (zagorchev, 1995; zagorchev et al., 1987). this regional metallogenetic unit is 250 km long (jankovic, 1997; jankovic et al., 1997) and is controlled by major fracture zones and spatial distribution of tertiary magmatism (fig. 2). the mineralization is related (harkovska et al., 1989; stojanov et al., 1995; boev et al., 1997; boev & yanev, 2001) to calc-alkaline complexes (rhyolite–quartz-latite–dacite/ andesite), which occur intermittently along the fracture zones from the oligo-miocene to lower early pliocene time, between figure 1. the geotectonic position of the jurassic ophiolites and ophiolitic belts in the central parts of the balkan peninsula (zagorchev et al., 2012). g eologia c roatica tasev et al.: evolution of ore-forming fluids in the bukovik-kadiica porphyry cu deposit, republic of macedonia 3 25 to and 14 ma. base metal mineralization (lead and zinc sulphides) dominate within this metallogenetic zone, with local occurrences of molybdenite and scheelite (stockwork-disseminated type mineralization and hydrothermal quartz veins), low-temperature stibnite, fluorite deposits and occasional cinnabar and barite occurrences. longitudinal zoning of mineral associations is well developed in the nw–se direction (serafimovski et al., 1997). the most important types of mineralization are: • skarn mineralization related to intercalations of marble in precambrian crystalline schist within the the serbo-macedonian massif. mineralization occurs in lenticular and stratabound ore bodies (e.g. the sasa pb-zn deposit). • hydrothermal stockwork mineralization developed along fault structures (e.g. baltašnica pb-zn-cu deposit). • hydrothermal veins emplaced in different lithological settings (common but mostly small and non-economic). the bukovik-kadiica area is composed mainly of ripheancambrian and palaeozoic metadiabases and schists (a diabasephyllite complex, vlasina complex) that have experienced greenschist facies metamorphism and display a well-developed schistosity. near berovo they directly overlie amphibolite-facies gneisses (karamata, 1974a; kockel et al., 1975, grubić, 1980; dumurdžanov et al., 2005). metadiabase and schist are cross-cut by dykes of younger gabbro and diabase. the age of the kadiica formation is postvendian and pre-permian (zagorchev, 1987), with metadiabases and schists discordantly covering the older frolosh forma tion (vlasina complex) at 530–550 ma (the u-pb zircon dating by graf, 2001; kounov, 2002; zagorchev et al., 2011a,b, 2012; kounov et al., 2012; kiselinov et al., 2014; figure 2. a structural-metallogenetic scheme for the besna kobila-osogovothasos zone (modified after janković et., 1997). figure 3. geological map of the bukovik-kadiica locality (modified after duzelkovski, 1960). g eo lo gi a c ro at ic a geologia croatica 71/14 antić et al., 2015). to the west the zone is bounded by a tertiary graben filled with eocene and pliocene sediments. north of belo brdo towards kriva buka and pančarevo, granitoids dominate. they are represented by granites, granite porphyries, and granodiorites. these igneous rocks build up a belt along the macedonian–bulgarian border. to the west, they subsided into the pehčevo-delčevo graben, and are covered with tertiary (palaeogene and neogene) sediments. the oldest rocks present are diorites, and they are cross-cut by granite-porphyries and granodiorites. they are all thought to be of palaeozoic age (stojanov et al., 1995). the granite-porphyries are a marginal facies of the hercynian delčevo granites. their age is proven by the presence of granite fragments within the younger permian and triassic conglomerates. the granitoids are cross-cut by diabase dykes near pančarevo. the granitoids are hydrothermally altered, most probably due to post-magmatic hydrothermal processes associated with the tertiary volcanic rocks. permian sediments (sands and claystone) lie transgressively over metagabbro-diabases and granodiorites. palaeogene products are represented by eocene sediments that, in accordance with their lithological features and superposition of layers, can be distinguished into grey conglomerate facies (conglomerate, breccia, sand, clay, and marl) and flysch facies (yellow sand with occasional intercalations of silty clays and microconglomerates with rhythmic alternation). 4. main geological features of the deposit tertiary volcanism in the bukovik-kadiica area is represented by the bukovik volcanic dome (1722 m) and small subvolcanic bodies of dacite and rhyodacite at belo brdo and kadiica (1932 m) covering an area of about 4 km2. small dacite bodies and dykes were discovered in bulgarian territory within a nw–se oriented zone, as well as a cryptodome with subvolcanic breccias at the intersection of faults of n-s and ne–sw strikes (harkovska, 1984). the kadiica subvolcanic intrusive centre is one of several neogene dacitic plugs that have intruded a variety of metamorphic rocks of the smm. several of these intrusives are associated with quartz vein stockwork development and widespread hydrothermal alteration. the subvolcanic intrusive complex is poorly exposed on bukovic hill (1722 m asl) and consists of flow-banded dacite and massive fine crystalline dacite that have been intruded by a coarser dacite phase, a quartz-, biotite-, and plagioclasephyric dacite porphyry, and a postulated second dacite porphyry at depth. near-surface pyroclastics and dacitic autobreccias are exposed along the southwest side of bukovic hill. according to harkovska (1984), harkovska et al. (1989), and stojanov et al. (1995), the kadiica intrusive complex has been dated as between 35 and 27 ma (oligocene; whole rock, k/ar method). an extensive area of brecciation consists predominantly of tectonic breccias associated with a northwest–southeast-striking major fault zone. late stage phreatic or phreato-magmatic breccias are intercepted at shallow levels in exploration drill holes (fig. 1). the subvolcanic intrusive complex has been intensely altered and is cut by numerous quartz, quartz-sulphide, and sulphide veins and veinlets. surface alteration is dominated by silicification with abundant limonite as disseminations and in veins with lesser amounts of kaolinite, sericite, and local alunite. the petrography of selected samples shows the presence of a near-surface advanced argillic overprint characterized by alunite with local diaspore and andalusite. alteration and metal zoning suggest the presence of a deeper dacite porphyry phase that was responsible for the formation of the large stockwork exposed at bukovic hill. alteration and weak copper mineralization are hosted by an oligocene dacitic volcanic complex (tasev, 2010), which has intruded into palaeozoic sediments, andesites, and gabbros (fig. 4). in particular, because the life span and thermal evolution of the hydrothermal system plays a major role in the understanding of the genesis of a particular hydrothermal ore deposit, this study has attempted to establish some constraints on the thermal evolution of the magmatic–hydrothermal system at the kadiica porphyry copper deposit using fluid inclusion analysis. 5. hydrothermal alteration hydrothermal alterations of the host rocks (dacite, trachydacite, and granodiorite) within the bukovik-kadiica deposit are widespread and distinctive and they reflect the spatial and temporal evolution of hydrothermal fluids. the overall form of the alteration system has a pin-like shape and distinctive alteration types overlap each other like layers of an onion (fig. 4). the alterations and the porphyry cu mineralization show an intimate genetic relationship. the overprint of older alteration zones by younger alterations reveals a sequential evolution of hydrothermal fluids and indicates that the alteration processes had a dynamic and complex character. the study and description of deep hypogene hydrothermal features have been complicated by a relatively deeply figure 4. geological cross section of the bukovik-kadiica locality (tasev, 2010) (the presence of metamorphic enclaves is idealized and these are probably more extensive than shown). g eologia c roatica tasev et al.: evolution of ore-forming fluids in the bukovik-kadiica porphyry cu deposit, republic of macedonia 5 figure 5. a) quartz-sericite assemblage alteration; b) quartz-sericite-biotite assemblage alteration; c) plagioclase relics in quartz-sericite assemblage alteration; d) coarse grained kaolinite alteration; e) epidote-smectite assemblage alteration; f ) quartz-chlorite-calcite assemblage alteration; g) quartz-alunite assemblage alteration; h) quartz-muscovite (sericite)-calcite assemblage alteration. a) b) c) d) e) f ) g) h) g eo lo gi a c ro at ic a geologia croatica 71/16 penetrating advanced argillic overprint and by subsequent supergene alteration that modified both the deep and shallow hydrothermal features. the distribution of hydrothermal alterations at the bukovikkadiica porphyry cu deposit differs from the common alteration zonation, with a potassic core, a phyllic alteration halo and a wider peripheral propylitic zone (e.g., lowell & guilbert, 1970; rusk et al., 2008). in contrast, this deposit is characte rized by distant zones of potassic, phyllic, argillic, propylitic, and an advanced argillic character as well as by the presence of limonitization. potassic alteration is represented by the mineral assemblage composed of k-feldspar, quartz, biotite and/or magnetite, amphibole, and anhydrite. magmatic biotite has been partly replaced by a mg-rich variety associated with rutile. this is the most widespread alteration type in the bukovik-kadiica ore district, located just above the granodiorite intrusion, but the biotite halo occupies a much wider area. usually potassic alteration is overprinted by lower temperature hydrothermal alteration assemblages. in the mineralized porphyry rocks and surrounding dacite-trachydacite, k-feldspar occurs as irregular replacements of the igneous matrix while in more pervasively altered samples it replaced the phenocrysts and destroyed the original igneous texture. similar features have been recognized in porphyry cu deposits elsewhere (e.g. li et al., 2013). phyllic alteration overprints the potassic alteration and at places is very intensive. it may form a wide halo around the mineralization, although it is also closely associated with the cu mineralization itself. its vertical extensions significantly exceed the horizontal dimensions. this type of alteration is characterized by the presence of quartz, sericite, and disseminated pyrite (fig. 5a). sericite is present as aggregates, while orthoclase and biotite are extensively altered to muscovite and partly to secondary biotite; primary biotite is altered to sericite (fig. 5b), and sericite has replaced plagioclase phenocrysts (fig. 5c). this type of alteration contains a significant amount of pyrite that is directly associated with the alteration process. phyllic alteration overlaps with the central parts of the mineralized zone (red zone shown in fig. 4), while the argillic alteration zone characterized by kaolinite replacement progresses outwards. similar features have been recognized in other porphyry cu deposits such as buchim (čifliganec, 1993), borov dol (gjorgjevic et al., 1975), morenci, ajo and bisbee (nash, 1976; misra, 2000). argillic alteration is intensive, but distal from the granodiorite intrusion, and is characterized by newly formed kaolinite at the expense of plagioclase. the primary textures are partly or figure 6. geological map of the bukovik-kadiica deposit (alexandrov & bombol, 2007). g eologia c roatica tasev et al.: evolution of ore-forming fluids in the bukovik-kadiica porphyry cu deposit, republic of macedonia 7 completely obscured, although quartz phenocrysts can still be recognized. primary plagioclase was replaced by kaolinite (usually closer to the intrusion area, fig. 5d), while montmorillonite occurs at higher levels (where hypogene mineralization is almost insignificant). the propylitic alteration zone is the dominating feature of the great majority of porphyry cu deposits, for example at plavica in the republic of macedonia (ivanov & denkovski, 1980; stojanov, 1980) as well as in deposits in the collahausi district-rosario, ujina, and quebrada blanca, then the los loros, los pelambres, bajo de la alumbrera, chuiquicamata deposits (all in chile), (taylor, 1935; sillitoe, 1973; urqueta et al., 2009). at the bukovik-kadiica deposit this alteration type is represented by a mixture of epidote, smectite chlorite, calcite, talc, and kaolinite (figures 5e, 5f). spatially, propylitic alteration characterizes the marginal parts of the hydrothermal system where fluid/rock ratios were the lowest. epidotization and chloritization were mainly associated with weak porphyry mineralization. the uppermost part of the bukovik-kadiica deposit is characterized by an advanced argillic alteration zone predominantly composed of quartz-, kaolinite, pyrite (±limonite), rutile and alunite (fig. 5g). the mineral assemblage suggests extremely low ph conditions and it is a common assemblage for shallow parts of porphyry cu deposits worldwide (e.g., sillitoe, 1973; gustafson & hunt, 1975; brimhall, 1979; thompson et al., 1986; lindhorst & cook, 1990; wormald & price, 1990). in some places, the surface of the advanced argillic alteration zone is covered by a very thin iron cap. carbonatization, although minor, occurs within the bukovik-kadiica deposit. however, precipitation of calcite succeeds sulphide mineralization (figure 5h). 6. mineralization the mineralized area (4 km2) consists of numerous dacite and rhyolite-dacite bodies and dykes that extruded through the smm basement of metamorphic rocks, represented mainly by chlorite-sericite schists, amphibolite and gneiss in the lowest parts (figure 6). emplacement and subsequent cooling of the complex resulted in intensive fracturing and brecciation. mineralized bo dies have different lens-like morphologies, with a ne-sw orientation, mostly due to differences in permeability of the host struc tures. the bukovik-kadiica deposit consists of of three distinctive mineralized zones: • a primary sulphide zone or hypogene mineralization • a secondary cu sulphide enrichment zone or cementation zone • an oxidation zone data collected from the drill cores revealed that a hypogene zone occurs at depths between 64 to 420 m, and has a variable thickness of 10 to 183 m. the cu content ranges from 0.007 up to 0.13%. in the deeper parts, the mineralization occurs in veins which mutually intersect. the most enriched stockworks were found at greater depths (> 200 m) in dacites. so far, significant hypogene mineralization has not been confirmed. the secondary cu sulphide enrichment (cementation) zone (figure 7) occurs at depths from 60 to 260 m below the surface, with an average thickness of 70 m, and reflects the level of ground water during deposition of the secondary mineralization. the horizontal dimensions of this zone are 1200 m x 700 m. it contains 70 mt of ore with an average grade of 0.22% cu (b+c1 category by the macedonian law of mineral resources and appropriate rulebook). gold and silver contents appear to be low (au < 0.6 g/t; ag up to 250 g/t, but usually <50 g/t). these ore reserves are economically exploitable and their calculation was based on 0.15% cu cut-off grade (serafimovski, 2012). the secondary cu sulphide enrichment zone consists predominantly of chalcocite, pyrite, molybdenite, chalcocite, bornite, covellite, dige nite, tetrahedrite-tennantite series minerals, as well as arsenosul vanite, colusite, and mawsonite (tasev, 2010). the cu distribution clearly defines the leached zone and an enriched copper zone with chalcocite precipitated far below the base of the oxidation zone. the chalcocite/covellite ratio changes vertically from the chalcocite predominant shallow parts to the covellite predominant deeper parts of the zone. however, the cu distribution in the deeper part within the majority of drilled holes does not show a clear enrichment trend. figure 8 illustrates the complete paragenetic sequence at the bukovik-kadiica deposit (fig. 8). the paragenetic sequence distinguishes an early magmatic mineral assemblage composed of rutile, magnetite, haematite and pyrite. however, the majority of the pyrite was deposited simultaneously with the propylitic alteration. the vast majority of ore minerals, including pyrrhotite, molybdenite, pyrite, chalcopyrite, sphalerite, enargite, galena, tetrafigure 7. cross section through the bukovik-kadiica deposit. g eo lo gi a c ro at ic a geologia croatica 71/18 hedrite, tennantite, famatinite, luzonite, proustite, and pyrargirite, was deposited during substage iii (fig. 8). the oxidation zone is fully developed and represented by limonite-silica masses. magnetite, chalcopyrite, rutile, haematite, and calcite have also been registered. copper concentrations in this zone ranges from 0.003–0.12% cu while the thickness (from the surface) varies from 20–130 m. copper was intensively mobilized and carried out of this zone, which is a common feature of pyrite-bearing mineralizations. oxidation of pyrite significantly decreases ph values and promotes mobilization of all metals, including cu. a carbonate rich lithology buffers the ph value of descending ground waters and allows deposition of malachite and azurite. 7. fluid inclusion methodology the mineralization in the bukovik-kadiica area has been studied using a variety of chemical and mineralogical techniques. intensive exploration activity was carried out during 2011 and 2012 figure 8. the paragenetic sequence of the bukovik-kadiica deposit. g eologia c roatica tasev et al.: evolution of ore-forming fluids in the bukovik-kadiica porphyry cu deposit, republic of macedonia 9 (including 16,500 m of drill core); and based on these findings reserves of 70 mt at a grade of 0.216% cu were estimated. at the same time as the exploration proceeded, detailed mineralogical and geochemical studies were performed (tasev, 2010). more detailed descriptions of the mineralization, focusing on the fluid inclusions in mineralized quartz samples are the target of the research (drill holes 09, 10, 11 complemented with those from 01 and 08). a fluid inclusion study was conducted on 23 samples of doubly polished, transparent plates of quartz, 150 μm thick, with numerous separate fluid inclusions (5–40 μm in size). quartz was selected from veinlets in dacites and fluid inclusions in calcites were also occasionally analysed (tasev, 2010). quartz samples were taken from stockworks which were exposed along a surface section over more than 100 m and from drill cores. fluid inclusions were evenly distributed in the studied quartz grains and only those with strong indications of primary origin (goldstein & reynolds, 1994), were taken into account during the microthermometric studies (roedder, 1984). figure 9. photomicrographs showing a) typical three-phase inclusion, crystalgas-liquid; b) presence of one elongated solid phase within the fluid inclusion; c) negative hexagonal crystal form entrapped in fluid inclusion in quartz; d) two and three phases fluid inclusions; e) large fluid inclusion rich with vapor. (transmitted light, plain polarized light). a) b) c) d) e) g eo lo gi a c ro at ic a geologia croatica 71/110 the study was performed using nikon and olympus bx51 optical microscopes and in each analysed sample, at least 20 inclusions were analysed. microthermometric data were obtained using a linkam thmsg600 heating–freezing stage (temperature range –196 oc to +600oc) and tms 90 controller attached to a conventional petrographic microscope. the stage was calibrated using the synflinc set of synthetic fluid inclusions and revealed a precision of ± 0.1°c for the freezing runs and ± 5°c for temperatures near to or higher than 360°c. fluid inclusions with homogenization temperatures higher than 600 °c were carried out on a modified leitz 1350 heating stage with precision of the measurement of ±5 °c. salinities are expressed as wt% nacl equivalent and were estimated from the melting temperatures of the last crystal of ice for two-phase fluid inclusions (bodnar, 1993) and from halite dissolution temperatures for multiphase inclusions (sterner et al., 1988). eutectic temperatures were used to estimate the overall composition of the studied fluid inclusions by comparison with published data for different salt-water systems (shepherd et al., 1985). in addition, calculation of kcl and possible cacl2 contents was performed according to the phase diagrams of roedder (1984) and vanko et al. (1988) respectively. the pressure of heterogeneous fluids has been determined using the method of sections of isochors and isotherms. data from thierry et al. (1994) were used in the construction of isochors and estimate of pressures in inclusions rich in a gaseous mixture. salinity and pressure were determined using flincor software (brown, 1989). in cases where primary fluid inclusions trapped heterogeneous fluid, indicative of boiling conditions, it was not necessary to perform corrections of homogenization temperatures for pressure conditions. 8. fluid inclusion data from the bukovik-kadiica petrographic studies at room temperature distinguished several types of fluid inclusions: three phase (multiphase) fluid inclusions (liquid /chloride solution/ + vapour /bubble/ + one or more translucent /halite or halite+sylvite/ or opaque daughter crystals /. the selection of fluid types ideally matches the model-type iii of nash and theodore, 1971; see fig. 9a; 9b; 9c; gas-rich fluid inclusions characterized by a thick liquid rim (sometimes with halite cube daughter crystal); and undersaturated two-phase, vapour-rich fluid inclusions. multiphase fluid inclusions, besides liquid and vapour, contain one or more solid phases (daughter crystals). the most common daughter crystal is halite determined by its cubic habit, isotropy as well as the same relief compared to quartz. dark opaque minerals were also observed (fig. 9d) but their identification was not possible using a transmitted light microscope. however, the triangular sharp habit indicates chalcopyrite morphology. this type of inclusion commonly shows a negative quartz crystal shape (fig. 9c). within some samples, three-phase types of fluid inclusion (l+v+sopaque) are associated with two-phase (l+v) inclusions (fig. 9d). two-phase inclusions with various ratios of liquid and vapour phases have been recorded as well, but in general, v-rich inclusions are more common than l-rich ones (fig. 9e). fluid inclusion assemblages composed of coexisting l-rich, v-rich and multiphase inclusions suggest an entrapment from boiling fluids. overlapping homogenization temperatures for inclusions with various phase ratios confirm the boiling environment. the studied fluid inclusions were divided into three main types according to their appearance at 25 °c (fig. 10): i three phase fluid inclusions, liquid (chloride solution) + vapour (bubble) + one or more translucent (halite or halite+sylvite) or opaque daughter crystals (almost an figure 10. types of fluid inclusions within the bukovik-kadiica ore deposit: (a, b) brine fluid inclusions (type i); (c) gaseous fluid inclusions (type ii); (d) unsaturated (without halite) fluid inclusions (type iii). the scale is 10 μm, transmitted light, plain polarized light (volkov et al., 2008; modified). figure 11. histograms of homogenization temperatures and salinities of fluid inclusions in ore associated quartz samples from the bukovik-kadiica deposit. g eologia c roatica tasev et al.: evolution of ore-forming fluids in the bukovik-kadiica porphyry cu deposit, republic of macedonia 11 ideal match to the model-type iii of nash and theodore, 1971; see figure 10a; 10b); ii gas-rich fluid inclusions characterized by a thick liquid rim (sometimes with a halite cube daughter crystal; see figure 10c); and iii undersaturated two-phase, vapour-rich fluid inclusions (figure 10d). the microthermometric data are summarized in table 1. temperatures are given as calculated mean temperatures for each sample. temperatures of salt dissolution are presented within brackets together with ice melting temperatures (tmice). the total homogenization of brine inclusions was recorded in a wide temperature interval from 501 to 310°c (fig. 11a). the halite melting temperature in the range between 383 and 211°c corresponds to a salinity of 45.66–32.4 wt% nacl equiv. (fig. 11b). the calculated fluid density varies from 1.16 to 0.90 g/cm3. the pressure was calculated and estimated, in accordance to the compiled data of haas (1976), haar et al. (1984), bodnar et al. (1985), sterner et al. (1988), bischof & pitzer (1989), knight & bodnar (1989) and atkinson (2002), from inclusions of saturated brines ranged from 90 to 620 bar. vapour-dominated fluid inclusions homogenize into a vapour phase at 497–438 °c (fig. 12). the final ice melting temtable 1. results of thermoand cryometric studies of individual primary fluid inclusions in quartz from ore veinlets of the bukovik-kadica deposit, macedonia (thomogen temperatures are calculated mean values for each sample). sample no. type of inclusion no. of inclusions °с сsalts, wt%nacl equiv. d, g/cm3 pressure, bar тhomogen. тeut. тice(halite) melt. 1 iii 13 627 –60 –27.4 24.3 0.58 925 2 iii 14 476 –42 –19.7 21.2 0.72 520 3 i 15 333 –55 (311) 38.9 1.06 – 4 i 16 334 –55 (299) 38.2 1.06 – 5 i 21 346 –55 (289) 37.4 1.04 100 6 i 14 331 –54 (283) 36.9 1.05 – 7 i 13 310 –55 (383) 45.6 1.16 620 8 i 13 326 –54 (294) 37.7 1.06 – 9 i 17 340 –49 (259) 35.2 1.02 90 10 iii 12 439 –48 –24.5 23.2 0.79 330 11 ii 14 463 –38 –7.0 10.5 – 480 12 iii 13 360 –25 –1.9 3.2 0.60 200 13 iii 13 378 –35 –6.9 10.4 0.70 220 14 iii 18 432 –36 –10.1 14.0 0.66 310 15 ii 15 438 –25 –3.9 6.3 – 370 16 i 14 337 –55 (211) 32.4 1.00 – 17 iii 14 526 –55 –19.9 22.3 0.65 660 18 ii 17 497 –54 –12.4 16.3 – 570 19 i 17 328 –55 (255) 35.0 1.03 90 20 i 12 501 –55 (317) 39.5 0.90 490 figure 12. summary plot of the microthermometric measurements (homogenization temperatures vs. salinities) in fluid inclusions from the bukovik-kadiica deposit. the saturation curve of nacl and the critical curve of the h2o-nacl system are given by sourirajan & kennedy, 1962 and haas, 1976; data for the saturation curve of kcl as summarized by potter et al. (1977). g eo lo gi a c ro at ic a geologia croatica 71/112 peratures reflect a salinity of 16–6 wt% nacl equiv. these inclusions define a pressure of 370–570 bar. two-phase (l+v) fluid inclusions homogenize into a liquid phase at 627–360 °c (fig. 12). their eutectic temperatures vary from –60 to –25 °c, indicating very diverse chemistry from a cacl2±mgcl2-nacl-h2o, kcl-nacl-h2o to nacl-h2o system (keevil, 1942; sourirajan & kennedy, 1962; helgeson, 1964; burnham, 1967; roedder, 1984; candela & piccoli, 1995; webster, 1997), which ascertains boiling in the system. the final ice melting temperature suggests a salinity of 24–3 wt% nacl equiv. (fig. 12). the calculated fluid density varies from 0.58 to 0.72 g/cm3. solid phases in some of the complex fluid inclusions were also analysed using a scanning electron microscope (sem/edx) (tasev, 2010). the identity of some ‘daughter’ minerals is confirmed as halite (minerals with cubic habit, preliminarily determined under the optical microscope) while the other defined as sylvite (although very rare, they dissolved into liquid in the range of 75-150 oc), quite similar to other porphyry copper deposits worldwide (anthony et al., 1984; roedder, 1984; bodnar, 1995; fan et al., 1998; xie et al., 2006; li et al., 2011). the salinities of fluid inclusions containing nacl and kcl daughter minerals (where kcl dissolutes as the last phase) were estimated by establishing the temperature of solution of nacl and kcl and referring to the phase data of linke (1965) and to the relevant part of the system nacl-kcl-h2o (roedder, 1984) as well as using cotectic boundaries given by sterner et al (1988). 9. discussion porphyry ore deposits represent the economically most important resources of cu and mo and host significant reserves of au, ag, and many other metals (sillitoe, 2005). porphyry deposits form at depths of approximately 1–6 km below the palaeosurface due to the condensation of supercritical fluids derived from a crystallizing magma reservoir in the shallow crust (e.g., seedorff et al., 2005; cooke et al., 2013). the fluid inclusion studies have been used to estimate the magmatic-hydrothermal fluid composition and p-t conditions associated with the bukovik-kadiica porphyry cu mineralization. although fluid inclusion data provide an exceptional insight into the physico-chemical properties of ore-forming fluids, multiple episodes of magmatic-hydrothermal fluxes associated with complex processes of mineral growth, mineral dissolution, fracturing and sealing in porphyry cu systems usually result in the entrapment of numerous generations of primary and secondary fluid inclusions within annealed host mineral grains and make interpretation of the obtained data vague (cooke et al., 2013). three recorded fluid inclusion types from the bukovik-kadiica porphyry cu deposit reflect the evolution of ore-bearing fluids within the p-t-x space. the results of microthermometric studies of over 450 individual fluid inclusions (see table 1) have shown that ore-bearing fluids contained dissolved chlorides of na, ca, and mg ± k. the earliest inclusions belong to the twophase (l+v) inclusion type. they are characterized by high homogenization temperatures and moderate salinities. inclusions of this type are usually considered as relicts of intermediate-density primary magmatic–hydrothermal fluids that are exsolved from the crystallizing and cooling intrusive magmatic body (e.g., landtwing et al., 2010; redmond et al., 2004; seo et al., 2012). the earliest, two-phase, high-temperature, moderate salini ty fluid inclusions are commonly overprinted with one or more generations of fluid inclusion assemblages consisting of coexisting figure 13. nacl-h2o p-t-x phase diagram (after driesner & heinrich, 2007; modified). the two white arrows represent stages when within system, due to change in p-t-x, other coexisting vapour and brine phases occurred other than the primary one. g eologia c roatica tasev et al.: evolution of ore-forming fluids in the bukovik-kadiica porphyry cu deposit, republic of macedonia 13 highto moderate-temperatures and low-salinity vapour-rich inclusions and multiphase high-salinity liquid-rich inclusions. this type of fluid inclusion assemblage reflects the separation of vapour from a liquid-like supercritical fluid (boiling) followed by condensation of a liquid, often of high salinity, from a supercritical fluid (e.g., bodnar et al., 1985, heinrich, 2005; heinrich, 2007). late-stage fluid inclusions are mostly two-phase (l+v) lowtemperature and low-salinity inclusions of intermediate to high density. they typically homogenize to liquid, but some vapourrich inclusions may be present that homogenize to vapour. such assemblages are indicative of boiling of low-salinity fluids (cooke et al., 2013). it is noted from the measurements that in all but one of the samples the halite crystal dissolves before the vapour bubble. generally, there are two potential causes for the formation of high-salinity fluid inclusions containing halite in porphyry copper deposits: (i) pressure reduction and phase separation from a low-salinity fluid (burnham, 1979; hedenquist & lowenstern, 1994; hedenquist et al., 1998; ulrich et al., 2001; klemm et al., 2007; landtwing et al., 2010); (ii) direct exsolution from the magma (roedder & coombs, 1967; cline & bodnar, 1991; hedenquist & lowenstern, 1994, 1994; shinohara, 1994; bodnar, 1995; kamenetsky et al., 1999; campos et al., 2002, 2009; veklser, 2004; webster & mandeville, 2007). as there are low-salinity vapour inclusions coexisting with high-temperature brines in the bukovik-kadiica porphyry copper deposit, we suggest that these saline fluids have directly exsolved by later boiling from a low-salinity fluid, rather than by direct exsolution from the magma. the high homogenization temperatures and salinities of the saturated fluid inclusions indicate the initial existence of a dense brine, single phase fluid (0.90–1.16 g/cm3, table 1), at magmatic temperatures (roedder, 1992; santana et al., 2011). coexistence of vapour like (low salinity) + two phase medium salini ty + very rare halite bearing fluid inclusion at the temperature between 400 and 500oc, however, is much more convincing for the boiling and separation of the original early high temperature phase into a heterogenous system. after physical separation from dense brine in fractured porphyry stock (due to immiscibility), only the less viscous and more buoyant vapour phase may rise to the epithermal environment (henley & mcnabb, 1978; heinrich et al., 1999). the coexistence of vapour-rich and high-salinity inclusions that homogenize within the same temperature range (table 1) suggests that these fluids represent two immiscible fluids that evolved from the dense magmatic fluid (santana et al., 2011). density and compositional differences between the saline and low-density fluids affects the physical and chemical behaviour of these fluids in the porphyry system, in turn affecting the distribution of the precipitated minerals. the present study shows that just slightly above 600oc and at a pressure above 900 bar (90 mpa), the first exsolved magmatic fluid must have been a two-phase medium-salinity fluid, l+v (fig. 13), followed by a gradual salinity decrease during magma crystallization at low temperature, which is very similar to the data given for some other deposits (kilinc & burnham, 1972; cline & bodnar, 1991; shinohara, 1994; candela & piccoli, 1995; cline, 1995; fournier, 1999; cline, 2003; harris et al., 2005; webster and mandeville, 2007). fluid exsolution from hydrous magma plays an important role in mineralization (hedenquist & lowenstern, 1994; webster, 1997; audétat & pettke, 2003; imai, 2005; kamenetsky & kamenetsky, 2010). notably early fluid exsolution is favourable for economic mineralization because it facilitates the transfer of ore-forming elements into the fluid (candela & holland, 1986; zhang et al., 2001; li et al., 2006). here it is apparent that at intermediate and low pressures (< 60 mpa), and temperatures lower than 500 oc, initial low-salinity magmatic fluids gradually increased in salinity during magma crystallization as the solubility decreased with falling temperature and daughter minerals (halite, sylvite, etc.) may have nucleated. immiscible fluids must have formed with compositions corresponding to the aforementioned type i, type ii, and type iii. these fluids correspond to the vapour and brine phases, respectively, which formed as a result of boiling. this fluid evolution pattern is quite similar to that proposed by williamsjones & heinrich (2005) for porphyry copper deposits, and furthermore the obtained p-t-x values fit quite well into the common range for porphyry deposits elsewhere (wilkinson, 2001). vapour-rich inclusions are interpreted as being coeval with multiphase brine inclusions or abundant liquid-rich inclusions, indicating that the ore-forming fluid was boiling (li et al., 2007). the fluid inclusion study demonstrates that at some point kadiica has experienced boiling of hydrothermal fluids. the coexistence of vapour-only and vapour-rich as well as high-salinity inclusions within the same fluid inclusion associations is considered evidence of boiling (hedenquist & lowenstern, 1994; heinrich, 2005), similar to descriptions form porphyry systems elsewhere (sourirajan & kennedy, 1962; roedder, 1979; hedenquist & lowenstern, 1994; gammons & williams-jones, 1997; heinrich, 2005). variations in salinity indicate boiling processes, which probably led to the deposition of certain metals (grancea et al., 2002). salinity variations could also be partially attributed to the existence of explosive volcanic stages (confirmed by determined phreatomagmatic breccia at bukovik-kadiica; westra, 2005), the fracturing of adjacent rock complexes, and similar processes. the appearance of high-salinity inclusions, beside low-salinity ones, indicates that during particular geological periods the bukovik-kadiica magmatic-hydrothermal system must have generated brine fluids from deeper reservoirs (not excluding some of the afore-mentioned possibilities: salinity increase as the system evolved; boiling at certain stages or some meteoric water overprint). high-salinity fluids (fluid inclusions up to 46 wt% nacl equiv.) probably played an important role in the polymetallic mineralization of the bukovik-kadiica deposit, since chloride complexes are an effective mode of metal transport (barnes, 1979). the displayed data are very common in porphyry copper deposits. here we would like to point out, that although some fluid inclusions have shown that cu commonly occurs at higher concentrations in vapour-type inclusions than in coexisting brine inclusions, the transport of certain elements (cu, au) or compounds in low-density fluids that preferentially partitioned into the vapour phase should be excluded since recent studies confirmed that cu concentrations in quartz-hosted fluid inclusions from magmatic–hydrothermal ore deposits do not represent pristine concentrations in the trapped fluids, but are modified by postentrapment diffusional exchange through the host quartz, where quartz-hosted fluid inclusions can diffusively loose or gain cu g eo lo gi a c ro at ic a geologia croatica 71/114 after entrapment (lerchbaumer & audétat, 2012; seo & heinrich, 2013). the early high-temperature fluid must have already been saturated in copper (chalcopyrite daughter crystals in fi), so that cu precipitation probably occurred before the onset of the main alteration and mineralization event, which could explain the low copper contents in the hypogene mineralization of the bukovikkadiica prospect. the abundance of solid phases both daughter (halite and occasionally sylvite) and opaque phases (ore minerals) suggest that they were part of the original fluid, which must have been rich in ore-forming elements (li et al., 2011). the occasional presence of daughter minerals, notably chalcopyrite, in type iii undersaturated fluid inclusions, indicates that the early derived aqueous fluid characterized by low-moderate salinity, moderate co2 contents, were cu rich and responsible for the transport of cu, fe, and s ± au, as suggested elsewhere (gonzalez-patida & levresse, 2003; redmond et al., 2004; rusk et al., 2008; rusk et al., 2011). the presence of alunite suggests that one part of the sampled area is located within the outer zones of mineralization, associated with argillic alteration, which is known to occur along the margin in a porphyry system (guilbert & park, 1996), and is confirmed for the bukovik-kadiica deposit (tasev, 2010). the large homogenization temperature range of 310–627oc is in accordance with a homogenization temperature range from 250 up to 550 oс (commonly boiling) which is characteristic for numerous porphyry copper deposits (moore & nash, 1974; gustafson & hunt, 1975; chivas & wilkins, 1977; moore & moore, 1979; ahmad & rose, 1980; beane & titley, 1981; klemm et al., 2007; klemm et al., 2008). boiling curves for nacl solutions (shepherd et al., 1985) and their relationship to th and depth, were used to calculate the palaeodepth of mineralization (~ 800 m) that suggests pressures typically between 300 and 1200 bar, which corresponds to a lithostatic load cover of 1–4 km (roedder, 1984; alumbrera: ulrich et al., 2001; bingham canyon: redmond et al., 2004). however, several episodes of possible boiling effects, the system with wide fluctuation of pressure, even volcanic extrusion and presence of phreato-magmatic breccias etc., assured us that is not convenient to judge the palaeodepth. relatively high metal concentrations (from a few parts per million up to weight percentages) have been determined in vapour-rich inclusions formed under pressures of 200 to 1000 bars and temperatures of 400–650 oс (williams-jones & heinrich, 2005). high copper concentrations, in volcanic vapour/gas, typically in the percentage range have been estimated from the size of chalcopyrite “daughter” crystals in fluid inclusions (roedder, 1971; eastoe, 1978; henley & mcnabb, 1978). type iii inclusions, with occasional small daughter opaque mineral (chalcopyrite) occurred at levels characterized by potassic alteration (its transitional parts to phyllic alteration). two phase, liquid-rich inclusions occurred in the propylitic envelopelike alteration and some peripheral parts of the argillic alteration. central parts of the phyllic alteration were dominated by type ii inclusions while going up to lower temperatures and pressures, toward the upper parts of the phyllic and lower parts of the argillic alteration, type i inclusions prevailed. although optional and despite the sometimes precluding nature of fluid inclusions in the interpretation of the origin of fluids (due to multistage trapping, overprinting etc.), these findings were consistent with those of beane & bodnar (1995) and rusk et al. (2008). 10. conclusions the extension, quantity, and quality, of the relatively newly discovered porphyry copper deposit of bukovik-kadiica, were defined at the beginning of 2013 after completion of detailed geological exploration by the kadiica metal company. porphyry copper mineralization is of the stockwork type within the brecciated dacite-andesite stock which intruded palaeozoic schists of the serbo-macedonian massif. the major ore mineral within the kadiica deposit is chalcocite, while within the mineral assemblage covellite, bornite, enargite, emplectite, pyrite, pyrrhotite, and chalcopyrite were also determined. these minerals are now mainly concentrated in the cementation zones. alteration minerals, which dominate in the hydrothermally altered dacite breccia, are quartz, sericite, calcite, chlorite, kaolinite, illite and alunite with progressive silicification being the most dominant. fluid inclusions in quartz veins of the brecciated dacite-andesite volcanic rocks have shown that hydrothermal solutions consisted mainly of chlorides of na, ca, k and mg with a wide range of salinity of 3–45 wt% equiv. the homogenization temperatures are within the range of 310 to 627 oc, which implies the development of primary sulphide associations at medium and high temperatures. the correlation of such high temperatures with the calculated pressures suggests that the studied fluids are related to magmatic fluids, which later transformed into ore-bearing hydrothermal fluids of pulsative character. the first exsolved magmatic fluids (above 600–610 oc and pressure above 900 bar) were two-phase and medium-salinity fluids, followed by a gradual decrease in salinity during magma crystallization at intermediate and low pressures (< 90 mpa), as well as a decrease in temperatures to below 500 oc. initial lowsalinity magmatic fluids gradully increased in salinity with magma crystallization as the solubility of solutes also decreased with falling temperature and separate crystals of daughter minerals could nucleate and grow. in this manner three immiscible fluids formed with compositions corresponding to the aforementioned type i, type ii, and type iii. the appearance of high-salinity inclusions, beside existing low-salinity ones, indicates that in particular geological periods of the existence of the bukovikkadiica magmatic-hydrothermal system there was a yield of brine fluids from deeper reservoirs although some other possibilities should not be excluded (salinity increase of the magmatic volatile phase as the system evolved; boiling only during certain stages or that there could be some meteoric water overprint). acknowledgement we greatly acknowledge the comments of the anonymous reviewer(s). references ahmad, s.n. & rose, a.w. (1980): fluid inclusions in porphyry and skarn ore at santa rita, new mexico.– econ. geol., 75, 229–250. doi: 10.2113/gsecongeo.75.2.229 alexandrov, m. & bombol, d. (2007): izveštaj od istražuvanjata vo periodot 2002-2006 na koncesijata kadiica-pehčevo [report of explorations in the period 2002-2006 of the concession kadiica-pehcevo – in macedonian].– phelps dodge exploration corporation, phoenix, arizona, usa, 30 p. anthony, e.y., reynolds, t.j. & beane, r.e. (1984): identification of daughter minerals in fluid inclusions using scanning electron microscopy and energy dispersive analysis.– amer. mineral., 69, 1053–1057. antić, m., peytcheva, i., von quadt, a., kounov, a., trivić, b., serafimovski, t., tasev, g., gerdjikov, i. & wetzel, a. (2016): pre-alpine evolution of a segment of the north-gondwanan margin: geochronological and geochemical evidence from the central serbo-macedonian massif.– gondwana resear., 36, 523–544, doi: 10.1016/j.gr.2015.07.020 g eologia c roatica tasev et al.: evolution of ore-forming fluids in the bukovik-kadiica porphyry cu deposit, republic of macedonia 15 arsovski, m. & ivanov, t. (1977): neotectonics magmatism and metallogeny on the territory of yugoslavia.– metallogeny and platetectonics in the ne mediterranean, belgrade, 471–482. atkinson, a.b.jr. (2002): a model for the ptx properties of h2o-nacl.– msc thesis, faculty of virginia polytechnic institute and state university, usa (comm: robert j. bodnar, cahit coruh and christine anderson-cook), 126 p. audétat, a. & pettke, t. (2003): the magmatic-hydrothermal evolution of two barren granites: a melt and fluid inclusion study of the rito del medio and canada pinabete plutons in northern new mexico (usa).– geoch. et cosmoch. acta, 67, 97–121. doi: 10.1016/s0016-7037(02)01049-9 barnes, h.l. (1979): solubilities of ore minerals.– in: barnes h.l. (ed): geochemistry of hydrothermal ore deposits. wiley, new york, 404–460. beane, r.e. & titley, s.r. (1981). porphyry copper deposits: part ii. hydrothermal alteration and mineralization.– econ. geol., 75th anniversary vol. (eds. skinner, j.b.), 235–269. beane, r.e. & bodnar, r.j. (1995): hydrothermal fluids and hydrothermal alteration in porphyry copper deposits.– in: pierce, f.w. & bohm, j.g. (eds): porphyry copper deposits of the american cordillera. ariz. geol. soc. dig., 20, 83–93. bischoff, j.l. & pitzer, k.s. (1989): liquid-vapor relations for the system nacl-h2o: summery of the ptx surface from 300º to 500ºc.– amer. j. sci., 289, 217–248. blundy, j., mavrogenes, j., tattitch, b., sparks, s. & gilmer, a. (2015): generation of porphyry copper deposits by gas-brine reaction in volcanic arcs.– nature geoscience, 8/3, 235–240. doi: 10.1038/ngeo2351 bodnar, r.j. & vityk, m.o. (1994): interpretation of microterhrmometric data for h2o-nacl fluid inclusions.– in: de vivo, b. & frezzotti, m.l. (eds): fluid inclusions in minerals: methods and applications. pontignano-siena, 117–130. bodnar, r.j., burnham, c.w. & sterner, s.m. (1985): synthetic fluid inclusions in natural quartz. iii. determination of phase equilibrium properties in the system h2o-nacl to 1000 c and 1500 bars.– geoch. et cosmoch. acta, 49/9, 1861–1873. doi: 10.1016/0016-7037(85)90081-x bodnar, r.j. (1995): fluid-inclusion evidence for a magmatic source of metals in porphyry copper deposits.– in: thompson, j.f.h. (ed.): magmas, fluids and ore deposits. mineral assoc can short course ser, 23, 139–152. bodnar, r.j. (1993): revised equation and table for determining the freezing point depression of h2o-nacl solutions.– geoch. and cosmoch. acta, 57, 683–684. doi: 10.1016/0016-7037(93)90378-a boev, b., janković, s. & serafimovski, t. (1997): magmatism and tertiary mineralization of the kozuf metallogenetic district, the republic of macedonia with particular reference to the alshar deposit.– spec. publ., no.5., faculty of mining and geology-štip, p 262. boev, b. & yanev, y. (2001): tertiary magmatism within the republic of macedonia: a review.– acta vulcanol., 13/1-2, 57–71. bogoevski, k. (1965): metalogenija povezana sa tercijernim magmatizmom u oblasti osogovo-besna kobila [metallogeny related to tertiary magmatism in the osogovo-besna kobila area – in serbian].– phd, faculty of mining and geology, university in belgrade, serbia, 243 p. boyanov, i., dabovski, c., gocev, p., harkovska, a., kostadinov, v., tzankov, t.z. & zagorcev, i. (1989): a new view of the alpine tectonic evolution of bulgaria.– geol. rhod., 1, 107–121. brimhall, g.h. jr. (1979): lithologic determinations of mass transfer mechanism of multiple-stage porphyry copper mineralization at butte, montana. vein formation by hypogene leaching and enrichment of potassium-silicate protore.– econ. geol., 74, 556–589. brown, p. (1989): flincor: a computer program for the reduction and investigation of fluid inclusion data.– amer. mineral., 74, 1390–1393. burchfiel, b.c., nakov, r., dumurdzanov, n., papanikolaou, d., tzankov, t., serafimovski, t., king, r.w., kotzev, v., todosov, a. & nurce, b. (2008a): evolution and dynamics of the cenozoic tectonics of the south balkan extensional system.– geosphere, 4/6, 919–938. burchfiel, b.c., king, w.r., nakov, r., tzankov, t., dumurdzanov, n., serafimovski, t., todosov, a. & nurce, b. (2008b): patterns of cenozoic extensional tectonism in the south balkan extensional system.– in: husebye, e. s. (ed.): earthquake monitoring and seismic jhazard mitigation in balkan countries. springer, 3–18. doi: 10.1007/978-1-4020-6815-7_1 burnham, c.w. (1967): hydrothermal fluids at the magmatic stage.– in:barnes, h. l. (ed.): geochemistry of hydrothermal ore deposits. new york: john wiley, 34–76. burnham, c.w. (1979): magmas and hydrothermal fluids.– in: barnes, h.l. (ed.): geochemistry of hydrothermal ore deposits, 2nd ed.: new york, wiley and sons, 71–136. campos, e., touret, j.l.r., nikogosian, i. & delgado, j. (2002): overheated, cu-bearing magmas in the zaldívar porphyry-cu deposit, northern chile: geodynamic consequences.– tectonophysics, 345, 229–251. campos, e., wijbrans, j. & andriessen, a.m.p. (2009): new thermochronologic constraints on the evolution of the zaldívar porphyry copper deposit, northern chile. – min. dep., 44/3, 329–342. candela, p.a. & holland, h.d. (1986): a mass-transfer model for copper and molybdenum in magmatic hydrothermal systems–the origin of porphyry-type oredeposits.– econ. geol., 81, 1–19. candela, p.a. & piccoli, p.m. (1995): model ore-metal partitioning from melts into vapor and vapor ⁄ brine mixtures.– in: thompson, j.f.h. (ed.): magmas, fluids, and ore deposits. mineralogical association of canada short course series, 23, 101–127. candela, p.a. & piccoli, p.m. (2005): magmatic processes in the development of porphyry-type ore systems. economic geolology, one hundred anniversary vo lume: 25–38. chivas, a.r. & wilkins, w.t. (1977): fluid inclusion studies in relation to hydrothermal alteration and mineralization at the koloula porphyry copper prospect, guadalcanal.– econ. geol., 72, 153–169. doi: 10.2113/gsecongeo.72.2.153 cline, j.s. & bodnar, r.j. (1991): can economic porphyry copper mineralization be generated by a typical calc-alkaline melt?– j. geophys. resear., 5, 8113–8126. doi: 10.1029/91jb00053 cline, j.s. (1995): genesis of porphyry copper deposits: the behaviour of water, chloride and copper in crystallizing melts.–ariz. geol. soc. digest, 20, 69–82. cline, j.s. (2003): how to concentrate copper.– science, 302, 2075–2076. cooke, d.r., & wilkinson, j.j. (2014): geochemistry of porphyry deposits.– treatise on geochemistry, second editionth edn. elsevier, oxford, 357–381. doi: 10.1016/b978-0-08-095975-7.01116-5 dabovski, c., boyanov, i., khrischev, k.h., nikolov, t., sapounov, i., yanev, y. & zagorchev, i. (2002): structure and alpine evolution of bulgaria.– geol. balc., 32/2-4, 9–15. dimitrijević, m.d. (1959): basic characteristics of the column of the serbo-macedonian mass.– abstracts of the first symposium of the serbian geological soc iety, belgrade. dimitrijevic, m. (1995): geology of yugoslavia.– geoinstitute, belgrade, 205 p. driesner, t. & heinrich, c.a. (2007): the system h2o-nacl. i. correlation formulae for phase relations in temperature-pressure-composition space from 0 to 1,000°c, 0 to 5000 bar, and 0 to 1 xnacl.– geoch. et cosmoch. acta, 71, 4880–4901. durmurdzanov, n., serafimovski, t. & burchfiel, b.c. (2004): evolution of the neogene-pleistocene basins of macedonia.– geological society of america, digital map and chart series mc01, 20 p. durmurdzanov, n., serafimovski, t. & burchfiel, b.c., (2005): cenozoic tectonics of macedonia and its relation to the south balkan extensional regime.– geosphere, 1/1, 1–22. duzelkovski, d. (1960): geološki sostav na terenot delčevo-pehčevo (planina vlaina) [geological composition of the terrain delčevo-pehčevo (vlaina mountain) – in macedonian].– papers of the geol. survey of the republic of macedonia, skopje, 7, 66–82. eastoe, c.j. (1978): fluid inclusion study of the panguna porphyry copper deposit, bougainville, papua-new-guinea.– econ. geol., 73, 721–748. doi: 10.2113/gsecongeo.73.5.721 fan, h.r., xie, y.h. & wang, y.l. (1998): determining daughter minerals in fluid inclusions under scanning electron microscope.– geol. sci. and techn. inform. 17(sup.), 111–117. fournier, r. (1999): hydrothermal processes related to movement of fluid from plastic into brittle rock in the magmatic–epithermal environment.– econ. geol., 94, 1193–1212. gammons, c.h. & williams-jones, a.e. (1997): chemical mobility of gold in the porphyry–epithermal environment.– econ. geol., 92, 45–59. gjorgjevic, v., karamata, s. & gjorgjevic, p. (1975): proučavanje hidrotermalnih alteracija lokalnosti borov dol [study of hydrothermal alterations at the borov dol locality – in serbian].– faculty of mining and geology, laboratory for petrology, belgrade, 30 p. goldstein, r.h. & reynolds, t.j. (1994): systematics of fluid inclusions in diagenetic minerals.– sepm short course 31. soc. for sediment. geol., 199 p. doi: 10.2110/scn.94.31 gonzalez-patida, e. & levresse, g. (2003): fluid inclusion evolution at the la verde porphyry copper deposit, michocan, mexico.– j. geoch. explor., 78/79, 623–626. graf, j. (2001): alpine tectonics in western bulgaria: cretaceous compression of the kraiste region and cenozoic exhumation of the crystalline osogovo-lisec complex.– phd eth no 14’238, zurich, switzerland, 197 p. grancea, l., bailly, l., leroy, j., banks, d., marcoux, e., milési, j.p., cuney, m., andré, a.s., istvan, d. & fabre, c. (2002): fluid evolution in the baia mare epithermal gold/polymetallic district, inner carpathians, romania.– min. dep. 37/6–7, 630–647. doi: 10.1007/s00126-002-0276-5 grubić, a. (1980): yugoslavia: outline of yugoslavian geology.– 26th internat. geological congress, paris, 615, 5–49. g eo lo gi a c ro at ic a geologia croatica 71/116 guilbert, j.m. & park, c.f. (1996): the geology of ore deposits.– fifth printing, w.h freeman and company, united states of america, 985 p. gustafson, l.b. & hunt, j.p. (1975): the porphyry copper deposit at el salvador, chile.– econ. geol., 70, 857–912. doi: 10.2113/gsecongeo.70.5.857 haar, l., gallagher, t.s. & kell, g.s. (1984): nbs/nrs steam tables: thermodynamic and transport properties and computer programs for vapor and liquid states in si units.– hemisphere, washington, dc, 120 p. haas, j. (1976): physical properties of the coexisting phases and thermochemical properties of the h2o component in boiling nacl solution (preliminary steam tables for nacl solution).– us geol. surv. bull., 1421-a, 1–71. hadži-petrusev, b. (1985): извештај за деталните истражувања на бакар на буковик-кадиица, берово [report of detailed copper explorations at the bukovik-kadiica, berovo – in macedonian].– geol. surv. maced., 78 p. harkovska, a. (1984): tertiary magmotectonic zones in southwest bulgaria.– in: vozar, j. (ed.): magmatism of the molasse-forming epoch and its relation to endogenous mineralization: bratislava, geologicky ustav dioyza stura, 9–34. harkovska, a., yanev, y. & marchev, p. (1989): general features of the paleogene orogenic magmatism in bulgaria.– geol. balc., 19/ 1, 37–72. harris, a.c., golding, s.d. & white, n.c. (2005): the genesis of bajo de la alumbrera deposit: stable isotope evidence for a porphyry-related hydrothermal system dominated by magmatic aqueous fluids.– econ. geol., 101, 71–94. hedenquist, j.w. & lowenstern, j.b. (1994): the role of magmas in the formation of hydrothermal ore deposits.– nature, 370, 519–527. doi: 10.1038/370519a0 hedenquist, j.w., arribas, a.j. & reynolds, t.j. (1998): evolution of an intrusion-centered hydrothermal system: far southeast-lapanto porphyry and epithermal cu-au deposits, philippines.– econ. geol., 93, 373–404. doi: 10.2113/ gsecongeo.93.4.373 heinrich, c.a. (2005): the physical and chemical evolution of low salinity magmatic fluids at the porphyry to epithermal transition: a thermodynamic study.– min. dep., 39, 864–889. doi: 10.1007/s00126-004-0461-9 heinrich, c.a. (2007): fluid-fluid interactions in magmatic-hydrothermal ore formation.– reviews mineral. and geoch., 65, 363–87. doi: 10.2138/rmg.2007.65.11 heinrich, c.a., günter, d., audétat, a., ulrich, t. & frischknecht, r., (1999): metal fractionation between magmatic brine and vapour, determined by microanalysis of fluid inclusions.– geology 27, 755–758. heinrich, c.a., halter, w., landtwing, m.r. & pettke, t. (2005): the formation of economic porphyry copper (-gold) deposits: constraints from microanalysis of fluid and melt inclusions.– in: mcdonald, i., boyce, a.j., butler, i.b., herrington, r.j. & polya, d.a. (eds): mineral deposits and earth evolution. geological society, london, special publications, 248, 247–263. doi: 10.1144/gsl.sp.2005.248.01.13 helgeson, h.c. (1964): complexing and hydrothermal ore deposition.– new york, pergamon, 136 p. henley, r.w. & mcnabb, a. (1978): magmatic vapor plumes and groundwater interaction in porphyry copper emplacement.– econ. geol., 73, 1–20. imai, a. (2005): evolution of hydrothermal system at the dizon porphyry cu-au deposit, zambales, philippines.– resource geol., 55, 73–90. doi: 10.1111/j.1751-3928. 2005.tb00230.x ivanov, t. & denkovski, dj. (1980): hydrothermal alterations in the plavica-zlatica porphyry copper deposit within the kratovo-zletovo volcanic area.– symposia alteration of rocks and minerals, 100 years of geological school and science in serbia, belgrade, 291 p. iveson, a.a., webster, j.d., rowe, m. c., & neill, o.k. (2016): magmatic– hydrothermal fluids and volatile metals in the spirit lake pluton and margaret cu–mo porphyry system, sw washington, usa.– contrib. mineral. and petrol., 171/3, 1–32. janković, s. (1977): the copper deposits and geotectonic setting of the tethyan euro asian metallogenetic belt.– mineral. dep., 12/1, 37–47. janković, s. (1997): the carpatho-balkanides and adjacent area: a sector of the tethyan eurasian metallogenetic belt.– min. dep., 32/5, 426–433. doi: 10.1007/ s001260050110 janković, s. & petkovic, m. (1974): metallogeny and concepts of the geotectonic development of yugoslavia.– metallogeny and concepts of the geotectonic development of yugoslavia, faculty of mining and geology-belgrade, 443–477. janković, s., petković, m., tomson, i.n. & kravcov, v. (1980): porphyry copper deposits in the serbo-macedonian province, southeastern europe.– in: janković, s. & sillitoe, r.h.( eds): european copper desposits, sga special publication no. 1, unesco-igcp projects no. 169 and 60, 96–102. janković, s. & serafimovski, t. (1997): specific features of mineralization related to different tectonic enviroments in the serbo-macedonian metallogenic province.–symposia-annual meeting, proceedings, dojran, 285–286. janković, s., serafimovski, t., jelenkovic, r. & cifliganec, v. (1997): metallogeny of the vardar zone and serbo-macedonian mass.–symposium-annual meeting, proceeding, dojran, 29-67. kamenetsky, v.s., wolfe, r.c., eggins, s.m., mernagh, t.p. & bastrakov, .e (1999): volatile exsolution at the dinkidi cu-au porphyry deposit, philippines: a melt-inclusion record of the initial ore-forming process.– geology, 27, 691–694. doi: 10.1130/0091-7613(1999)027%3c0691:veatdc%3e2.3.co;2 kamenetsky, v.s. & kamenetsky, m.b. (2010): magmatic fluids immiscible with silicate melts: examples from inclusions in phenocrysts and glasses, and implications for magma evolution and metal transport.– geofluids, 10, 293–311. doi: 10.1111/j.1468-8123.2009.00272.x karamata, s. (1974a): the geological evolution of the area of yugoslavia: the nature and movements of plates and importance of these properties and processes for metallogeny.– metallogeny and concepts of the geotectonic developments of yugoslavia, belgrade, 109–118. karamata, s. (1974b): geološki razvoj naše oblasti: karakteristike i pokreti nekih ploča i važnost tih karakteristika i procesa za metalogeniju [geological development of our area: characteristics and movements of particular plates and importance of those features and processes to the metallogeny – in serbian].– in: metallogeny and conceptions of the geotectonic development of the yugoslavia, faculty of mining and geology, belgrade, 89–97. keevil, n.b. (1942): vapor pressures of aqueous solutions at high temperatures.– amer. chem. soc. j. 64, 841–850. kilinc, i.a. & burnham, c.w. (1972): partitioning of chloride between a silicate melt and coexisting aqueous phase from 2 to 8 kilobars.– econ. geol., 67, 231–235. doi: 10.2113/gsecongeo.67.2.231 kiselinov, h., peychev, k., georgiev, s. & peytcheva, i. (2014): new geochronology data on the lower cambrian age of the frolosh metamorphic complex (frolosh unit) and kadiytsa formation-sw bulgaria. bul. shk. gjeol. 1/2014, special issue, proceedings, xx congress of the carpathian-balkan geological association, tirana; 200–202, 2014. klemm, l.m., pettke, t. & heinrich, c.a. (2007): hydrothermal evolution of the el teniente deposit, chile-porphyry cu-mo ore deposition from low-salinity magmatic fluids.– econ. geol., 102, 1021–1045. doi: 10.2113/gsecongeo.102.6.1021 klemm, l.m., pettke, t. & heinrich, c.a. (2008): fluid and source magma evolution of the questa porphyry mo deposit, new mexico, usa.– min. dep., 43, 533–552. doi: 10.1007/s00126-008-0181-7 knight, c.l. & bodnar, r.j. (1989): synthetic fluid inclusions: ix. critical pvtx properties of nacl-h2o solutions.– geoch. cosmoch. acta, 53, 3–8. doi: 10.1016/0016-7037(89)90267-6 kockel, f., mollat, h. & gundlach, h. (1975): hydrothermaly altered and (copper) mineralized porphyritic intrusions in the serbo-macedonian massif (greece).– min. dep., 10, 195–204. koděra, p., heinrich, c. a., wälle, m. & lexa, j. (2014): magmatic salt melt and vapor: extreme fluids forming porphyry gold deposits in shallow subvolcanic settings.– geology, 42/6, 495–498. doi: 10.1130/g35270.1 kovacević, m., rakičević, t. & arsovski, m. (1973): tolkuvač za geološka karta list delčevo [guide for geological map sheet delčevo – in macedonian].– geological survey of the republic of macedonia, skopje, 55 p. kounov a (2002). thermotectonic evolution of kraishte, western bulgaria.– dissertation eth 14946, zurich, 219 p. kounov, a., graf, j., quadt, a.v., bernoulli, d., burg, j.-p., seward, d., ivanov, z. & fanning, m. (2012): evidence for a “cadomian” ophiolite and magmatic-arc complex in sw bulgaria.– precambrian research, 212–213; 275–295. landtwing, m., furrer, c., redmond, p., pettke, t., guillong, m. & heinrich, c.a. (2010): the bingham canyon porphyry cu-mo-au deposit. iii. zoned copper-gold ore deposition by magmatic vapour expansion.– econ. geol., 105, 91–118. lerchbaumer, l. & audétat, a. (2012): high cu concentrations in vapor-type fluid inclusions: an artifact?.– geoch. et cosmoch. acta, 88, 255–274. doi: 10.1016/j.gca.2012.04.033 li, j.x., qin, k.z. & li, g.m. (2006): the basic characteristics of gold–rich porphyry copper deposits and their ore sources and evolving processes of high oxidation magma and ore-forming fluid.– acta petrol. sin., 22, 678–88. li, g.m., li, j.x., qin, k.z., zhang, t.p. & xiao, b. (2007): high temperature, salinity and strong oxidation ore-forming fluid at duobuza gold-rich porphyry copper in the bangonghu tectonic belt, tibet: evidence from fluid inclusions study.– acta petrol. sin., 23, 935–952. li, j.x., li, g.m., qin, k.z. & xiao, b. (2011): high-temperature magmatic fluid exsolved from magma at the duobuza porphyry copper–gold deposit, northern tibet.– geofluids, 11, 134–143. li, n., chen, y.j., pirajno, f. & ni, z.y. (2013): timing of the yuchiling giant porphyry mo system, and implications for ore genesis.– min. depos., 48/4, 505–524. doi: 10.1007/s00126-012-0441-4 lindhorst, j.w. & cook, w.g. (1990): gindinbung gold-silver deposit, temora.– australas. inst. of min. and metall. monogr, 14/2, 1365–1370. linke, w.f. (1965): solubilities of inorganic and metal-organic compunds.– k-z (4th ed.) washington, american chemical society, v. 2, 1, 914 p. g eologia c roatica tasev et al.: evolution of ore-forming fluids in the bukovik-kadiica porphyry cu deposit, republic of macedonia 17 lowell, j.d. & guilbert, j.m. (1970): lateral and vertical alteration-mineralization zoning in porphyry ore deposits.– econ. geol., 65, 373–408. doi: 10.2113/ gsecongeo.65.4.373 misra, k. (2000): understanding mineral deposits. kluwer academic publishers, dodrecht, netherland, 845 p. doi: 10.1007/978-94-011-3925-0 moore, w.j. & nash, j.t. (1974): alteration and fluid inclusion studies of the porphyry copper ore body at bingham, utah.– econ. geol. 69, 631–645. doi: 10.2113/ gsecongeo.69.5.631 moore, f. & moore, d.j. (1979): fluid inclusion study of mineralization at st. michaels mount, cornwall.– trans. of the inst. of min. and metall. (sec.b), 88, 57–60. nash, j.t. (1976): fluid-inclusion petrology-data from porphyry copper deposits and application to exploration.– geology and resources of copper deposits, united states department of interior and geological survey, d1-d16. nash, j.t. & theodore, t. (1971): ore fluids in the porphyry copper deposit at copper caynon, nevada.– econ. geol., 66, 385–399. potter, r.w. ii., babcock, r.s. & brown, d.l. (1977): new method for determining the solubility of salts in aqueous solutions at elevated temperatures.– j. res. u.s. geol. surv., 5/3, 389–395. proffett, j.m. (2003): geology of the bajo de la alumbrera porphyry copper–gold deposit, argentina.– econ. geol., 98, 1535–1574. redmond, p.b., einaudi, m.t., inan, e.e., landtwing, m.r. & heinrich, c.a. (2004): copper deposition by fluid cooling in intrusion-centered systems: new insights from the bingham porphyry ore deposit, utah.– geology, 32, 217–220. doi: 10.1130/g19986.1 richards, j.p. (2003): tectono-magmatic precursors for porphyry cu-(mo-au) deposit formation.– econ. geol., 98, 1515–1534. doi: 10.2113/gsecongeo.98.8.1515 robertson, a., karamata, s. & šarić, k. (2009): overview of ophiolites and related units in the late palaeozoic–early cenozoic magmatic and tectonic development of tethys in the northern part of the balkan region.– lithos, 108/1–4, 1–36. roedder, e. (1971): fluid inclusion studies on the porphyry-type ore deposits at bingham, utah, butte, montana, and climax, colorado.– econ. geol., 66, 98–120. roedder, e. (1979): fluid inclusions as samples of ore fluids.– in: barnes, h.l. (ed.): geochemistry of hydrothermal ore deposits: new york, wiley, 684–737. roedder, e. (1984): fluid inclusions.– rev. min., 12, 644 p. roedder, e. (1992): fluid inclusion evidence for immiscibility in magmatic differentiation.– geoch. cosmoch. acta, 56, 5–20. doi: 10.1016/0016-7037(92)90113-w roedder, e. & coombs, d.s. (1967): immiscibility in granitic melts, indicated by fluid inclusions in ejected granitic blocks from ascension island.– j. of petrol., 8, 417–451. rusk, b.g., reed, h.m. & dilles, h.j. (2008): fluid inclusion evidence for magmatic-hydrothermal fluid evolution in the porphyry copper-molybdenum deposit at butte, montana.– econ. geol., 103/2: 307–334. doi: 10.2113/gsecongeo.103.2.307 santana, m.m.u., moura, m.a., olivo, g., botelho, n.f., kyser, t.k. & bühn, b. (2011): the la unión au ± cu prospect, camagüey district, cuba: fluid inclusion and stable isotope evidence for ore-forming processes.– min. depos., 46/1, 91–104. seedorff, e., dilles, j.h., proffett, j.m., einaudi, m.t., zucher, l., stavast, w.j.a., johnson, d.a. & barton, m.d. (2005): porphyry deposits: characteristics and origin of hypogene features.– econ. geol., 100, 251–298. seo, j.h. & heinrich, a.c. (2013): selective copper diffusion into quartz-hosted vapor inclusions: evidence from other host minerals, driving forces, and consequences for cu–au ore formation.– geoch. et cosmoch. acta, 113, 60–69. doi: 10.1016/j. gca.2013.03.016 serafimovski, t. (1990): metalogenija na zonata lece-halkidiki [metallogeny of the lece-chalkidiki zone – in macedonian].– phd faculty of mining and geology, stip, 380 p. serafimovski, t. (1993): strukturno-metalogenetski karakteristiki na zonata lecehalkidiki: tipovi na rudni naogjalista i distribucija [structural metallogenetic characteristics of the lece-chakidiki zone: types of mineral deposits and distribution – in macedonian with extended summary in english].– spec. ed. of rgf stip, 1, 328 p. serafimovski, t., jankovic, s. & cifliganec, v. (1995): alpine metallogeny and plate tectonics in the sw flank of the carpatho-balkanides.– geol. maced., 9/1, 3–14. serafimovski, t., tomson, i.n. & kocneva, n.t. (1997): alpine orogenic structures and metallogeny in the serbo-macedonian massif and the vardar zone of the territory of macedonia.– in: boev, b. & serafimovski, s. (eds): symposium-annual meeting dojran, proceed., 113–117. serafimovski, t., tasev, g., blazev, k. & volkov, a. (2010): major alpine structures and cu-porphyry mineralization in the serbo-macedonian massif.– geol. maced., 24/1, 39–48. serafimovski, t. (2012): elaborat od izvršenite detalni geološki istražuvanja na mineralnata surovina bakar na lokalnosta kadiica, pehčevo [elaborate of detailed geological explorations of copper in the kadiica locality, pehcevo – in macedonian].– faculty of natural and technical sciences for dptu kadiica dooel pehčevo, 208 p. shepherd, t., rankin, a.h. & alderton, d.h.m. (1985): a practical guide to fluid inclusion studies.– blackie, glasgow, 240 p. shinohara, h. (1994): exsolution of immiscible vapor and liquid phases from a crystallizing silicate melt: implications for chlorine and metal transport.– geoch. et cosmoch. acta, 58, 5215–5221. doi: 10.1016/0016-7037(94)90306-9 sillitoe, h.r. (1973): the tops and bottoms of porphyry copper deposits.– econ. geol., 68, 799–815. doi: 10.2113/gsecongeo.68.6.799 sourirajan, s. & kennedy, g.c. (1962): the system h2o-nacl at elevated temperatures and pressures.– amer. j. sci., 260, 115–141. sterner, s.m., hall, d.l. & bodnar, r.j. (1988): synthetic fluid inclusions. v. solubility relations in the system nacl-kcl-h2o under vapor saturated conditions.– geoch. cosmoch. acta, 52, 989–1005. doi: 10.1016/0016-7037(88)90254-2 stojanov, r. (1980): vulkanska doma plavica, polimetalični mineralizacii i neposredni alteracii [volcanic dome plavica, polymetalic mineralizations and adjacent alterations – in macedonian].– symposia alteration of rocks and minerals, 100 years of geological school and science in serbia, belgrade, p. 291. stojanov, r. & aleksandrov, m. (1990): tercieren vulkanizam vo zonata sasatoranica [tertiary volcanism in the sasa-toranica zone – in macedonian].– xіі congr. of geol. of yugoslavia, ohrid, 371–386. stojanov, r., hadži-petrusev, b. & aleksandrov, m. (1995): daciticrhyolitic volcanic products at bukovic-kadijca(pehčevo district) and the related porphyry copper mineralization – geol. balk., 25-5/6, 83–90. stojanović, m. (1969): geološki sklop na poširokata oblast bukovik (pehčevo), so pregled na geološko-mineraloškite i genetskite karakteristiki na naogjalištata na limonitski breči [geological setting of wider area of the bukovik (pehčevo), with review of geological-mineralogical and genetic features of limonite breccia deposits in macedonian].– papers of geol. surv. of the rep. of maced., 14, 27–36. taylor, a.v.jr. (1935): ore deposits at chuquicamata, chile in copper resources of the world.– 16th internat. geol. cong., washington, 2, 473–484 tasev, g. (2010): metalogenija na polimetaličniot rudonosen system bukovik-kadiica [metallogeny of the polymetallic ore bearing system bukovik-kadiica – in macedonian].– phd, university “goce delčev”-stip, faculty of mining, geology and polytechnics, 207 p. thiery, r., kerkhof, am. & dubessy, j. (1994): vx properties of ch4-co2 and co2-n2 fluid inclusions: modeling for t<31 ºc and p<400 bars.– eur. j. min., 6, 753–771. thompson, j.f.h., lessman, j. & thompson, a.j.b. (1986): the temora goldsilver deposit: a newly recognized style of high sulfur mineralization in the lower paleozoic of australia.– econ. geol., 81, 732–738. doi: 10.2113/gsecongeo.81.3.732 ulrich, t., günther, d. & heinrich, c.a. (2002): evolution of a porphyry cuau deposit, based on la-icp-ms analysis of fluid inclusions, bajo de la alumbrera, argentina.– econ. geol., 97, 1888–1920. doi: 10.2113/gsecongeo.97.8.1889 urqueta, e., kyser, k., clark, a., stanley, c. & oates, c. (2009): lithogeochemistry of the collahuasi porphyry cu-mo and epithermal cu-ag (-au) cluster, northern chile: pearce element ratio vectors to ore.– geochem. expl. envir. anal, 9, 9–17. vanko, d.a., bodnar, r.j. & sterner, s.m. (1988): synthetic fluid inclusions. viii. vapor-saturated halite solubility in part of the system nacl-cacl2-h2o, with application to fluid inclusions from oceanic hydrothermal systems.– geoch. cosmoch. acta, 52, 2451–2456. veksler, i.v. (2004): liquid immiscibility and its role at the magmatic-hydrothermal transition: a summary of experimental studies.– chem. geol., 210, 7–31. doi: 10.1016/j.chemgeo.2004.06.002 volkov, a.v., tasev, g., prokof’ev, v.yu., serafimovski, t., tomson, i.n. & sidorov, a.a. (2008): formation conditions of copper porphyry mineralization in the kadica–bukovik ore district, eastern macedonia.– dokl. earth sci., 421/5, 769–773. webster, j.d. (1997): exsolution of magmatic volatile phases from cl-enriched mineralizing granitic magmas and implications for ore metal transport.– geoch. cosmoch. acta, 61, 1017–1029. doi: 10.1016/s0016-7037(96)00395-x webster, j.d. & mandeville, c.w. (2007): fluid immiscibility in volcanic environments.– rev. min. geoch., 65, 313–62. doi: 10.2138/rmg.2007.65.10 westra, g. (2005): remaining exploration potential in the kadiica porphyry copper prospect near berovo, macedonia.– internal report prepared for phelps dodge corp., 11 p. wilkinson, j.j. (2001): fluid inclusions in hydrothermal ore deposits.– lithos, 55, 229–272. doi: 10.1016/s0024-4937(00)00047-5 williams-jones, e.a. & heinrich, a.c. (2005): 100th anniversary special paper: vapor transport of metals in magmatic-hydrothermal systems.– econ. geol., 100, 1287–1312. wormald, r.j. & price, r.c. (1990): the gabbro-quartz monzonite-alkali granite association in southern nsw: implications for intrusive related gold mineralization.– geological society of australia abstracts series, 25, 265–266. g eo lo gi a c ro at ic a geologia croatica 71/118 xie, y.l., yi, l.s., xu, j.h., li, g.m., yang, z.m. & yin, s.p. (2006): characteristics of ore-forming fluids and their evolution for chongjiang copper deposit in gangdese porphyry copper belt, tibet: evidence from fluid inclusions.– acta petrol. sin., 22, 1023–1030. zagorchev, i. (1987): stratigraphy of the diabase-phyllitoid complex in sw bulgaria.– geol. balc., 17/3, 3–14. zagorchev, i. (1995): pre-palaeogene alpine tectonics in southwestern bulgaria.– geol. balc., 25/5–6, 91–112. zagorchev, i., moorbath, s. & lilov, p. (1987): radiogeochronological data about the alpine magmatism in the western part of the rhodope massif.– geol. balc., 17/2, 59–71. zagorchev, i. & milovanovic, d. (2006): deformations and metamorphism in the eastern parts of the serbo-macedonian massif.– proceed. 18th congress carpatho balkan geological association, belgrade, 670–673. zagorchev, i., dabovski, c. & dumurdzanov, n. (2008): tectonic structure of bulgaria and macedonia based on transmed transect iii.– in: boev, b. & serafimovski, t. (eds): proceedings: the first congress of geologists of the rep. of macedonia, 75–83. zagorchev, i., balica, c., balintoni, i., kozhoukharova, e., dumitrescu, r., sabau, g. & negulescu, e. (2011a): new isotopic data on the metamorphic rocks in sw bulgaria.–3rd international symposium on the geology of the black sea region, bucharest, 223–225. zagorchev, i., balica, c., balintoni, i., kozhoukharova, e., dumitrescu, r., sabau, g. & negulescu, e. (2011b): new isotopic data on the cadomian age of the frolosh metamorphic complex and the struma diorite complex.– geosciences’ 2011, sofia, 77–78. zagorchev, i., balica, c., balintoni, i., kozhoukharova, e., săbău, g. & negulescu, e. (2012): palaezoic evolution of the ograzhden unit (serbomacedonian massif, bulgaria and macedonia).– in: jovanovski, m. & boev, b. (eds): proceedings book: second congress of geologists of the republic of macedonia, krusevo, spec. issue of geol. maced. no. iii, 13–18. zagorchev, i., balica, c., kozhoukharova, e., balintoni, i., săbău, g. & negulescu, e. (2015): cadomian and post-cadomian tectonics west of the rhodope massif – the frolosh greenstone belt and the ograzhdenian metamorphic supercomplex.– geol. maced., 29/2, 101–132. zhang, d.h., zhang, w.h. & xu. g.j. (2001): exsolution and evolution of magmatic hydrothermal fluids and their constraints on the porphyry ore-forming system.– earth sci. front., 8, 194–202. čifliganec, v. (1993): copper mineralization in the republic of macedonia: types and distribution patterns: with special reference to the porphyry copper deposit bucim.– university “sts. cyril and methodius”skopje, faculty of mining and geology, special issue 1, 303 p. in memoriam ivan jurković fellow of the croatian academy of sciences and arts, professor emeritus university of zagreb  doi: 10.4154/gc.2015.13 on 30th december 2014 at the age of 98 years, after a period of declining health, we lost a prominent croatian geologist, a long time fellow of the croatian academy of sciences and arts, public employee – minister of science, rector of the university of zagreb, when professor emeritus of the ­faculty­of­mining­and­geology­ivan­jurković­passed­away.­ as­well­as­being­a­geologist­(the­field­where­his­lifelong­ work was dedicated) his loss was accepted with sadness in the circle of soil scientists as well as agricultural scientists. we remember him primarily as a superior intellectual, naturalist, with a special, subtle feeling for the moment, particularly the right moment in science and higher education and his ability to choose the right direction with an uncompromising commitment to the implementation of carefully selected and designed solutions to problems. in the history of croatian science he was responsible for a major step forward marked by the beginning of an “era of information technology” period with the founding of the university computing centre, university of zagreb (srce), as well as the construction, creation of the concept and framework of activities of the national and university library (nsk), for which he laid the cornerstone. in addition to leaving a deep and indelible mark in the development of mining geology and geological services in croatia­and­the­former­yugoslavia,­the­academician­jurković­ is merited with the inventory of natural resources of croatia. jurković­was­resolutely­focused,­(at­a­ time­when­it­was­ needed) on the production of the geological map and especially the general soil map of croatia (gsm) at a scale of 1:50 000. as he oversaw the creation of the gsm he noted down problems and noticed some weaknesses in its preparation.­the­scientific­project­general­soil­map­of­croatia­was­ not easy to authorize, especially when inaugurated as a longterm project that will “outlive the mandate of the minister “. his request was that the pedocartographic work engaged all­institutions­and­qualified­individuals­experienced­in­this­ specific­research­area,­which­included­field­work,­laboratory­ soil­analysis­as­well­as­preparation­of­the­map­and­textbook,­ for each area of the map across the territory of croatia. he observed problems and solved them in specific research projects.­this­meant­the­coordination­of­the­work­of­experts­ based on small, narrow research areas, with different habits, levels­ of­ knowledge,­ experience­ and­ styles­ of­working.­ jurković­particularly­stressed­(when­the­project­council­of­the­ soil map of croatia at a scale of 1:50 000 was formed and entrusted to him), the importance of preserving the creativity and personality as valuable characteristics of the individuals involved in the project. as the geomorphology, geological – lithological structure directs the process and results of soil genesis,­prof.­jurković­supported­the­project­and­acquired­the­ advice­of­mirko­malez,­a­very­experienced­fellow­of­the­ croatian academy, who has always been a great help. professor­emeritus­ivan­jurković­was­among­the­few­ who understand the peculiarities of agricultural sciences. these are related to the fact that when researching perennial species, the biological response doesn’t match the current treatment­and­pattern­of­studies,­so­the­results­cannot­be­expected in the normal course of the four year project period. neither before nor since, has a minister with such understanding been in post. numerous particular and zagreb located institutes were linked in the unique agricultural institute of zagreb. one of his assistants was an agronomist. prof.­ivan­jurković­acquired­and­held­his­high­reputation­ both at home and abroad, as well as teaching, research and being­a­public­servant.­his­erudition,­self-sacrificing­work­and­ attitude towards work were a role model for younger faculty members. it is safe to say that he has left a deep and indelible mark in the croatian sciences, in agricutural sciences and higher education. we­express­genuine­empathy­with­our­fellow­geologists,­ and­extend­the­same­feelings­to­the­respected­family­jurković.­ may his great and wide soul rest in peace. ferdo­bašić fellow of croatian academy of science and arts prof. emeritus, university of zagreb faculty of agriculture available online june 19, 2015 geologia croatica 68/2 171 zagreb 2015 geologia croaticageologia croatica 1. introduction carboniferous rocks are present at the surface in several scattered areas in croatia (ramovš et al., 1990; sremac, 2005) (fig. 1). in all these areas pennsylvanian deposition was influenced by the input of terrestrial debris, and by the occurrence of land flora. the most interesting pennsylvanian outcrops are described from the external (karst) dinarides (figs. 1, 3). a rather continuous carboniferous-permian succession of sedimentary rocks is exposed as the core of the velebit anticline (locality 1). late palaeozoic rocks are present as scattered outcrops with tectonic boundaries in the gorski kotar region (locality 2). mountains of nw croatia (medvednica, samoborska gora and marijagorička brda) (locality 3), are situated in the zagorje-mid-transdanubian zone, a dislocated section of the internal dinarides with mixed clastic-carbonate deposition during the palaeozoic era. the banovina region (locality 4), with deposits ranging in age from the devonian to the end-permian, belongs to the internal dinarides, representing the platform edge (e.g., pamić & jurković, 2002) (figs. 1, 3). the slavonian mts. (papuk mt.) and moslavačka gora mt. (locality 5) with a metamorphic palaeozoic complex, belong to the tisia unit (figs. 1, 3) (pamić & jurković, 2002; vozarova et al., 2009). late palaeozoic rocks were first studied in croatia for the purpose of geological mapping during the austro-hungarian monarchy in the 19th century. the first collections of carboniferous land flora in croatia were discovered during ore exploitation in the area of trgovska gora mt. (geinitz, 1868; stur, 1868) and the lika region (nemĕjc, 1939). salopek and his team performed detailed geological studies of the late palaeozoic deposits, producing precise maps of velebit mt. and the lika and gorski kotar regions (salopek, 1942, 1948, 1949, 1960), while collecting numerous samples for further palaeontological studies. carboniferous marine fossils were determined by kochansky-devidé (1955, 1970), kostić-podgorska (1956), kochansky & herak (1960), đurđanović (1968, 1973), rukavina (1973), balaž (1981) and milanović (1982). during the field work in northern croatia, jenko (1944) and herak (1956) reported spoab stra ct sedimentary rocks of pennsylvanian age outcrop at several regions in croatia. most of these rocks were deposited in a marine environment, in different tectonic units: karst (external) dinarides, internal dinarides and tisia. pennsylvanian deposits contain a significant amount of terrestrial debris, related to the uplift of the hercynian mountain belt and its intense erosion. remnants of land flora are not common, but are present at almost all localities. the most diverse and the best preserved pennsylvanian land flora in croatia was discovered on the velebit mt. and in the lika region. it was dominated by ferns, pteridosperms and cordaitales. the fossil flora from banovina is less diverse, with pteridosperms, scarce ferns, horsetails and lycopods. the sporadic occurrence of lycopods and horsetails was reported from the mountains of nw croatia. in the gorski kotar region only plant detritus was observed. ferns and pteridosperms from papuk mt. were discovered in older, mississippian deposits. palaeobotanical data reopen the discussion about the palaeogeographic position of the research areas. keywords: pennsylvanian, terrestrial sedimentation, megaflora, croatia geologia croaticageologia croatica influence of terrestrial sedimentation in pennsylvanian rocks of croatia  jasenka sremac institute of geology and palaeontology, department of geology, faculty of science, university of zagreb, horvatovac 102 a, zagreb, croatia; (jsremac@geol.pmf.hr) doi: 104154/gc.2012.18 geologia croatica 65/3 273–282 3 figs. 1 tab. zagreb 2012 geologia croatica 65/3geologia croatica 274 radic occurrences of terrestrial megaflora in the marijagorička brda hills and samoborska gora mt. a new cycle of mapping for the basic geological map of yugoslavia 1:100 000 yielded new information. carboniferous areas in croatia were presented as sheets and in explanatory booklets crikvenica l33-102 (grimani et al., 1970, 1973), daruvar l33-95 (jamičić, 1989; jamičić et al., 1989), delnice l33-90 (savić & dozet, 1985 a,b), gospić l33-127 (sokač et al., 1974, 1976a), ivanić-grad l33-81 (basch 1981, 1983), obrovac l33-140 (ivanović et al. 1973, 1976), orahovica l33-96, jamičić & brkić, 1988; jamičić et al., 1987), udbina l33-128 (šušnjar et al., 1973; sokač et al., 1976b) and zagreb l34-98 (šikić et al., 1978, 1979). during this period, brkić et al. (1974) described mississippian plant fossils from the slavonian mts. the last mapping cycle in croatia resulted in the new geological map of croatia 1:300 000 and explanatory text with description of stratigraphic units (velić & vlahović, eds., 2009). 2. carboniferous outcrops in croatia 2.1. velebit mt. and the lika region the most complete succession of clastic and carbonate deposits from the pennsylvanian (moscovian) to the end of the permian and the beginning of the triassic (ramovš et al., 1990; sremac, 2005), can be derived from an elongate ca. 50 km long palaeozoic belt, striking nw-se, exposed as the core of the velebit anticline in the external dinarides (figs. 1, 3). carboniferous outcrops are presented on the basic geologic map of yugoslavia, sheets gospić l33-127 (sokač et al., 1974, 1976), obrovac l33-140 (ivanović et al., 1973, 1976) and udbina l33-128 (šušnjar et al., 1973; sokač et al., 1976). pennsylvanian deposits in velebit mt. and the lika region are represented by shallow marine clastic-carbonate rocks of moscovian to gzhelian age (fig. 2). 2.1.1. fossiliferous clastic-carbonate rocks: (moscovian – kasimovian) the lowermost carboniferous horizon outcrops in the area of štikada and sv. rok (velić et al., 2009). dark-grey finely bedded shale contains quartz greywacke and crinoid limestone/dolomite intercalations (salopek, 1942, 1948). numerous brachiopods and bryozoans are present in the yellowish-weathered shale. a moscovian age was first determined on the basis of fusulinids and calcareous algae (kochansky-devidé, 1955, 1970). it can be considered as the equivalent of the fusulinella-protriticites zone (merinotomé et al., 2009). lower kasimovian sediments contain the first fusulinid taxa with keriothecal wall-structure, such as pro­ triticites (kochansky-devidé, 1955, 1970). phylloid algae (eugonophyllum, anchicodium) and shamovella (tubi­ phytes) are common in limestone intercalations. contact with younger deposits is partially tectonic, and partly exhibits a continuous transition (velić et al., 2009). 2.1.2. fusulinid (“triticites”) sandstone: (kasimovian) shale, sandstone and conglomerate rhythmically alternate within this horizon. fine-grained well sorted greywacke dominates in the lower portion and shale is more common in the upper layers. the input of terrestrial debris is significant. elongate fusulinids are often dissolved and washed out, with a dark brown film covering empty casts, due to the fresh-water influence and activity of iron synthesising bacteria. conglomerate appears in the form of lenses or intercalations within the shale, sometimes with gradational or oblique bedding. quartz pebbles predominate, but radiolarian chert, pyroclastic and siltite materials are also present. fossiliferous limestone lenses are scarce, also containing terrigenous quartz grains (velić et al., 2009). late-diagenetic dolomitization is common. on the basis of fusilinids: eoparafusulina pusilla (schellwien), e. pseudosimplex (chen) and „triticites” brevispira kochansky-devidé (kochansky-devidé, 1955), this horizon can be considered as an equivalent of the montiparus zone (merino-tomé et al., 2009). 2.1.3. shale and sandstone with land flora: (late kasimovian – gzhelian) late kasimovian deposits are highly fossiliferous and comparable to the auernig beds of the carnic alps (fritz & krainer, 2006) and partly to some localities in the karavanke alps in slovenia (kochansky-devidé & ramovš, 1966; kolar-jurkovšek & jurkovšek, 2002; jurkovšek, 2012). they can be considered as equivalent of the rauserites zone (merino-tomé et al., 2009). these rocks are lithologically similar to the previous units, but with evidence of increased terrestrial influence. figure 1: tectonostratigraphic units of the circum pannonian region with the position of carboniferous outcrops in croatia (modified after vozarova et al., 2009). jasenka sremac: influence of terrestrial sedimentation in pennsylvanian rocks of croatia geologia croatica 275 shale, slate and sandstone with scarce intercalations of limestone and quartz conglomerate contain numerous fossils. limestone intercalations are the most fossiliferous. they contain dasyclad anthracoporella spectabilis pia (kochansky-devidé & herak, 1960; kochanskydevidé, 1970), crinoids, brachiopods, bivalves, corals and foraminifera (simić, 1935; salopek, 1942, 1948; rukavina, 1973; balaž, 1981). diverse plant fossils (table 1) occur within shale and greywacke. well preserved lycopods (lepidodendron), sphenophytes (sphenophyllum), ferns (asterotheca, pecopteris, remia), pteridosperms (callipteridium, laveineopteris, linopteris, nemejcopteris, taeniopteris, sphenopteris) and conifers (pseudomariopteris, cordaites) were collected by a coal-mining company in the early 20th century and described by nĕmejc (1936). salopek and his team discovered some new plant fossils during mapping in the area (salopek, 1942, 1948) and the croatian museum of natural history recently discovered one new locality with a terrestrial megaflora (đerek, 2011, unpublished). zagreb plant collections were exhibited to participants of the igcp 575 zagreb meeting (2011) and examined in detail by y. tenchov and c. cleal (plants), as well as e. jarzembowski (insect traces). plant taxa from the literature are presented at the table 1, and new data are prepared and will be published separately. 2.1.4. lower rattendorf limestone (gzhelian) in the eastern part of the velebit palaeozoic belt, the terrestrial influence is prolonged into the permian, resulting in carbonate-siliciclastic deposition. western localities are characterized by dominantly carbonate rocks (equivalent of rattendorf group), with large spherical preudoschwagerinids, small benthic foraminifera and calcareous algae (salopek; 1942, 1948; kochansky-devidé, 1959) (fig. 2). 2.2. gorski kotar region late palaeozoic rocks in the gorski kotar region (fig. 1) outcrop as tectonically isolated blocks. salopek and his team prepared the first detailed maps and lithofacies descriptions (salopek, 1949, 1960). the area is represented on the basic geologic map of yugoslavia, sheets crikvenica l33-102 (grimani et al., 1970, 1973) and delnice l33-90 (savić & dozet, 1985 a, b). pennsylvanian rocks are interpreted as marine turbidite deposits (šparica, 2009). the oldest autochthonous rock at the surface is the fusulinid sandstone, with fusulinella sp. div., some peculiar “triticites” species and small schubertellids and endothyroids. a greywacke type of sandstone contains a significant amount of terrestrial debris and probably belongs to the moscovian and/or kasimovian periods (milanović, 1982; šparica, 2009). dark-grey, solid sandstone at first glance seems similar to the fusulinid sandstone of velebit mt. (kochanskydevidé, 1955). it is brown at the weathering surface, with numerous small cavities appearing after the dissolution of fusulinids. parallel orientation of fusulinids or their moulds is typical for these rocks, indicating postmortem transport (milanović, 1982). small, unrecognizable fragments of land flora can be found sporadically, probably transported down the slope by turbidite currents. carboniferous fossils also appear in clasts and pebbles of younger clastic deposits (sremac & aljinović, 1997; aljinović & kozur, 2003; aljinović et al., 2006). 2.3. medvednica, samoborska gora and the marijagorička brda mts. northwestern croatia with medvednica, samoborska gora and the marijagorička brda mts. belongs to the zagorjemid-transdanubian zone (fig. 1). this tectono-stratigraphic figure 2: schematic stratigraphic columns at different carboniferous regions in croatia. deposit thickness not to scale (partly after ramovš et al., 1990; pamić & jurković, 2002; vozarova et al., 2009, revised). geologia croatica 65/3geologia croatica 276 table 1: list of carboniferous megaflora from different localities in croatia. external dinarides: v velebit (nĕmejc, 1936); internal dinarides: sg samoborska gora mt. (herak, 1956); mb marijagorička brda hills (jenko, 1944); tg trgovska gora mt. (stur, 1868); tisia: p papuk (brkić et al., 1974). modern assignment after laveine (2005), zodrow et al. (2006) and bashforth et al. (2010). carboniferous terrestrial flora in croatia modern assignment v sg mb tg p lycopodiophyta           lepidodendron sp. x         lepidostrobus geinitzi zeiller x         lomatophloios crassilepis zeiller x         stigmaria ficoides brongniart       x   sigillaria sp.   x       equisetophyta           calamites suckowi brongniart       x   calamites cf. carinatus sternberg     x     sphenophyllum angustifolium germar x         asterophyllites equisetiformis (schloth.) brongniart         x annularia stellata schlotheim x         annularia sphenophylloides (zenker) gutbier x         calamospora sp.         x polypodiophyta           acitheca polymorpha (brongniart) němejc       x   asterotheca arborescens schlotheim x         asterotheca candoleana brongniart x         asterotheca cf. paleacea zeiller pecopteris x         pecopteris sp.         x dactylotheca plumosa artis pecopteris,seftenbergia x         crossotheca cf. pinnatifida (gutbier) remia x         ptychocarpus unitus brongniart x         pteridospermales           alethopteris aquilina schlotheim       x   alethopteris bohemica (franke) laveineopteris x         imparipteris (neuropteris) attenuata lindley & hutton laveineopteris         x imparipteris (neuropteris) cf. tenuifolia schlotheim laveineopteris         x callipteridium pteridium (schlotheim) zeiller x         linopteris duplex němejc x         pecopteris feminaeformis (schlotheim) nemejcopteris x         neuropteris auriculata (brongniart) neurodontopteris       x   odontopteris subcrenulata (rost) zeiller x         sphenopteris carnoti zeiller taeniopteris x         sphenopteris cf. haidingeri (ettingshausen) taeniopteris       x   sphenopteris cf. weissi (potonié) x         cyclopteris sp. x         cordaitales           cordaites palmaeformis goeppert x         cordaites principalis germar         x cordaicarpus ovoides (goeppert & berger) seward x         diplotmema busqueti zeiller pseudomariopteris x         diplotmema ribeyroni zeiller pseudomariopteris x         carpolites sp. x         jasenka sremac: influence of terrestrial sedimentation in pennsylvanian rocks of croatia geologia croatica 277 unit, striking sw-ne, was interpreted as a dislocated part of the internal dinarides (pamić & tomljenović, 1998; tomljenović et al., 2003). the area is mapped on the basic geologic map, sheets ivanić-grad l33-81 (basch 1981, 1983) and zagreb l34-98 (šikić et al., 1978, 1979). contacts with the surrounding mesozoic rocks are tectonic. parametamorphic, previously clastic and carbonate rocks of late palaeozoic age surround the orthometamorphic core of medvednica mt. some of these rocks are ore-bearing, originating from chert, tuffitic shale and sandstone. a black, low-metamorphic complex of dominantly phyllite appears in different areas (belak, 2009), and ranges from early silurian to pennsylvanian age, based upon conodonts and graptolites (đurđanović, 1973; sremac & mihajlović-pavlović, 1981). recrystallized carbonate rocks outcrop in scattered areas. they contain conodonts in their lower portions (devonian, mississippian) and shallow marine stromatoporids and bryozoans in their upper parts (pennsylvanian) (đurđanović, 1973; kochansky-devidé, 1981). the whole complex is highly tectonized and it is difficult to reconstruct a stratigraphic column (fig. 2) of this area (šikić et al., 1978; basch, 1981; šikić, 1995). metamorphism is linked with the alpine tectonic cycle (belak, 2009). west of medvednica mt., in the marijagorička brda hills, clastic deposits contains remnants of the carboniferous horsetail calamites (diplocalamites) cf. carinatus sternberg (jenko, 1944). this horsetail occurs in namurian and westphalian deposits of europe. coarse-grained greywacke, sandstone and black shale indicate a significant terrestrial influence and resemble the protolite rocks in the parametamorphic medvednica complex. pennsylvanian rocks outcrop in deep gorges and creeks. palynomorph analysis performed in 2011 did not provide new results (brajković, pers. comm.). farther westwards, discovery of the lycopod sigillaria was reported from samoborska gora mt. by herak (1956). the dominant sedimentary rocks are lithoclastic and quartz greywackes. quartz conglomerate appears sporadically, sometimes with lenses of shale and siltite. limestone and dolomite are developed laterally (šparica, 2009). detrital quartz in carbonate rocks indicates the continuous terrestrial input. palynological investigations performed in the late eighties were sterile (koch, pers. comm.). carboniferous marine fossils were not found in this area, but the uppermost limestone intercalations contain late permian marine calcareous algae (herak & škalec, 1967). shallow marine dolomites and limestones are ore-bearing, with meso-epithermal fe-cu-ba sedex type deposits (palinkaš et al., 2010). 2.4. the banovina-kordun region clastic middle-late palaeozoic deposits with intercalations of fossiliferous carbonate rocks occur at trgovska gora mt. in the banovina-kordun region (fig.1). this region is represented on the basic geologic map, sheet orahovica l3396 (jamičić et al., 1987; jamičić & brkić, 1988). detailed palaeozoic stratigraphy of this region was not studied, but fossils belong to the devonian and carboniferous periods. shale, siltstone and sandstone dominate, containing scarce conglomerate lenses in upper horizons. rhythmic alteration and gradation indicate the turbidite origin of these deposits (šikić, 2009). organic matter and chert lenses are common in the lower parts of the succession, and terrigenous input is more significant in the upper portion. conodonts, radiolarians and scarce ostracods from pelagic dark-grey argillaceous limestone range from the devonian to early carboniferous (viséan) in age (đurđanović, 1968, 1973). ba-f mesothermal mineralization and fe replacement are reported from these deposits (borojević-šoštarić et al., 2009). pennsylvanian uplift processes changed the mode of deposition. milanović (1982) studied dark-grey, mosaictextured dolomite from this horizon and determined small foraminifera and calcareous algae (tuberitina bulbacea galloway & harlton, dvinella (trinodella) vario­ longa kulik and solenopora sp.), crinoids and echinoids. he presumed shallow marine deposition during the moscovian. kasimovian-gzhelian carbonate rocks contain a coral fauna, described by kostić-podgorska (1955), and are comparable to that of the carnic alps. ba epithermal and fe sedex ore deposits from these rocks represent the prolongation of the ore-bearing horizon from the sana-una unit and are connected with opening of the tethys ocean (palinkaš et al., 2008). a terrestrial land flora ranging from the pennsylvanian to early permian in age was discovered in 19th century, as a result of ore exploitation in trgovska gora (geinitz, 1868; stur, 1868). the pennsylvanian flora is represented by horsetails calamites suckowi brongniart, lycopsid roots stigmaria ficoides brongniart and pteridosperms: sphe­ nopteris cf. haidingeri ettingshausen, neurodontop­ teris auriculata (brongniart) and alethopteris aquilina (schlotheim) (table 1) and shows similarity with the euroamerican palaeoprovince. early permian taxa include odontopteris obtusiloba naumann and calamites gigas brongniart (stur, 1868). 2.5. slavonian mts. – moslavačka gora mt. the mountains of eastern croatia (papuk mt., moslavačka gora mt.) represent the only carboniferous area in croatia out of the dinarides, forming part of the europaean tisia unit (figs. 1, 3). this area is represented on the basic geologic map, sheets daruvar l33-95 (jamičić, 1989; jamičić et al., 1989) and orahovica l33-96 (jamičić & brkić, 1988; jamičić et al., 1987), and is described by jamičić & crnko (2009). crystalline to low-grade parametamorphic rocks from the slavonian mountains range from early palaeozoic to the triassic. within the strongly tectonized low-metamorphic “radlovac” unit, interpreted as intertidal deposits (ramovš at al., 1990), a pennsylvanian (westphalian) land flora was found in metagreywackes and metasandstones (fig. 2). the geologia croatica 65/3geologia croatica 278 source of the clastic material is the uplifted papuk mt. with granite and metamorphic rocks. quartz grains are the most common (approximately 50 % grains), followed by plagioclase and micas. scarce horsetails, ferns and pteridosperms occur within the greywacke (asterophyllites equisetiformis (schlotheim) brongniart, pecopteris sp., lavein­ eopteris cf. tenuifolia schlotheim, laveineopteris rar­ inervis (bunbury) cleal et al. (= imparipteris attenuata lindley & hutton)), together with cordaites prin ci pa­ lis germar, and palynomorpha: calamospora, cordaites and cyrtospora (brkić, jamičić & pantić, 1974; jerinić et al., 1994) (table 1). the freshwater bivalve carboni­ cola was also observed in these deposits. deposition in the early permian was influenced by uplift processes (jamičić, 1989; jamičić & crnko, 2009). 3. discussion during the devonian and early carboniferous, the territory of croatia was part of a deep ocean. pelagic fossils (radiolarians, conodonts and/or spores) have been discovered in the dinarides (gorski kotar, medvednica and banovina) and tisia (slavonian mts.). uplift processes enabled the formation of the bashkirian-moscovian carbonate platforms at the western palaeotethys shelf (merino-tomé et al., 2009), including the area of velebit mt. and the lika region. intense erosion of the variscides at the end of the moscovian enabled massive siliciclastic input into the marine basin. deposits at all croatian dinaride localities exhibit this environmental change. nutrients derived from land to the shelf areas, together with terrestrial debris, resulted in increased biodiversity of the marine flora and fauna in the kasimovian and gzhelian. uplifted areas were colonised by land flora. palaeogeographic reconstructions of the carboniferous period presume the position of the dinaride localities along the shelf of northern gondwana (dimichelle et al., 2005; vozarova et al., 2009) (fig. 3). a diverse megaflora from velebit mt. was found in shale, siltite and thin coal intercalations of late kasimovian-gzhelian age (fig. 2). it consists of scarce lycopsids and horsetails, and common and well preserved ferns, pteridosperms and cordaitales (table 1). nĕmejc (1936) suggested a stephanian age for the described collection, which is in accordance with the age of marine fossils. nĕmejc also pointed out the lack of conifers in the velebit flora. such vegetation might be related to a local precipitation pattern. the prevalence of ferns and pteridosperms over lycopods and horsetails reflects global climate trends in the area (cleal et al., 2011). plant fossils are well preserved, with no traces of perturbations, due to the sheltered environment and lack of transport (tenchov, 2011, pers. comm.). marine foraminifera, bivalves and gastropods from this area are widely spread along euramerican shelves (kochanskydevidé, 1955; rukavina, 1973; balaž, 1981), whereas the calcareous algae are partly endemic in character (kochansky-devidé, 1970). distribution of the marine fauna was controlled by the anticlockwise ocean circulation. late palaeozoic deposits in the gorski kotar are dominantly clastic and appear as scattered, tectonically outlined patches. deposition by turbidite currents took place at the shelf slope. the land flora is present only in the form of detritus, and pennsylvanian marine fossils can be compared to those from velebit mt. the peculiar position of the nw croatian mountains: medvednica, samoborska gora and marijagorička brda has been discussed by many geologists. these mountains are positioned opposite to the dinaric strike, but they have some characteristics of the internal dinarides. pamić and tomljenović (1998) proposed the name zagorje-midtransdanubian zone for this belt (fig. 1). the palaeozoic sedimentary succession of mt. medvednica can be interpreted as a low-metamorphic turbidite sequence. pennsylvafigure 3: late variscan palaeogeography of the circum pannonian region (after vozarova et al., 2009) with the presumed position of croatian carboniferous terrains. jasenka sremac: influence of terrestrial sedimentation in pennsylvanian rocks of croatia geologia croatica 279 nian uplift was followed by colonization of the first shelf biota – crinoids, stromatoporids and bryozoans (kochansky-devidé, 1981), comparable with marine faunas from the euramerican shelf palaeoprovince. the conodont genus idiognathoides (đurđanović, 1968, 1973) has also been observed in north america and northern europe. farther westwards, the terrestrial influence is more pronounced, and sporadic occurrences of land megaflora, ca­ lamites cf. carinatus and sigillaria, were reported from the marijagorička brda hills and samoborska gora mt. (jenko, 1944; herak, 1956). the predominantly clastic deposits from these two mountains are not metamorphosed and exhibit different characteristics from the se parts of medvednica mt. lack of marine fossils does not allow precise zonation, but calamites carinatus is known from the namurian-westphalian of euramerica. the banovina region and trgovska gora mt. represent a prolongation of the ore-bearing sana-una unit and are interpreted as the internal dinarides. in a regional reconstruction (e.g. vozarova et al., 2009), they are situated near the gondwana shelf edge, towards the palaeotethys deep basin (fig. 3). turbidite deposition during the mississippian probably took place on the marginal slope. during the namurian and westphalian this area was uplifted. the calcareous alga dvinella, a cosmopolitan genus of the northern hemisphere, inhabited shelves surrounding the uplifted islands and produced biogenic bafflestone-type limestone. emergent areas were colonized by lycopsids (stigmaria fi­ coides), horsetails (calamites suckowi) and pteridosperms (alethopteris aquilina, neurodontopteris auriculata, taen­ iopteris cf. haidingeri) (table 1). the same taxa occur in the pennsylvanian of northern america and europe (czech republic, france, hungary) (gulyas-kis, cs., 2003; zodrow et al, 2006). zodrow et al. (2006) suggest the origin of the marattialen fern acitheca in north america and western europe in the middle pennsylvanian, with later expansion into eastern europe, caucasus, and into the permian of china. a wide stratigraphic range, from the middle pennsylvanian into the permian, is also reported for neurodon­ topteris auriculata (boyarina, 2010). nevertheless, the presence of lycopods and horsetails would suggest a probable middle pennsylvanian (stephanian a?) age for this flora. moslavačka gora mt. and papuk mt. in slavonian mts. belong to the entirely different tisia unit (figs. 1–3). uplift in the area took place during the mississippian, and the prominent influence of igneous rocks and metamorphism is typical for the area. determined plant fossils include asterophyl­ lites equisetiformis, laveineopteris rarinervis, l. cf. tenuifolia and cordaites principalis. they differ from the described dinaride floras in age (westphalian) and composition (brkić et al., 1974). 4. conclusion pennsylvanian deposition in croatia was strongly influenced by terrestrial input in the marine (western palaeotethys) basin, due to the variscan orogeny and intense erosion of the hercynian mountains. some of the uplifted areas were soon colonised with land flora. remnants of the pennsylvanian megaflora occur at croatian localities from different tectonic units: the external dinarides, internal dinarides and tisia. pennsylvanian vegetation in the dinarides was fern dominated, with an additional cordaite dryland flora in the area of velebit mt. and the lika region. a precise age is not always clear, due to the lack of index fossils. fossil horsetails from the marijagorička brda hills are probably the oldest terrestrial plants in the region, belonging to the namurian or westphalian. pteridosperms and ferns from trgovska gora, together with scarce lycopods and horsetails could be compared with stephanian a vegetation in euramerica. plant fossils from velebit mt. and lika region are the most diverse and well preserved, with no traces of transport. lycopods, horsetails, ferns, pteridosperms and cordaitales were found in this area, while primitive conifers are missing. the age of the velebit flora is estimated to be stephanian b or c (kasimovian-gzhelian). plant remnants in gorski kotar are in form of debris, due to the transport by turbidity currents. the tisia megaunit with the papuk and moslavačka gora mts. was dislocated from the dinarides. a westphalian flora from this region is similar to the flora of eastern america and central europe. it is necessary to continue with the regional study of croatian carboniferous localities in order to understand the palaeogeographic relationship between these areas during the pennsylvanian age. acknowledgement this paper is a contribution to the international geoscience programme – igcp project 575. research was supported by the croatian ministry of science, education and sports through the project 119-1951293-1162. the author is grateful to reviewers dr. ivo velić and dr. chris cleal for their most useful suggestions. references aljinović, d. & kozur, w.h. (2003): resedimented carboniferous and lower permian radiolarians in roadian (middle permian) deepwater clastic complex of gorski kotar region (croatia).− in: vlahović, i. (ed.): 22nd ias meeting of sedimentology − opatija 2003, abstracts, geološki institut, zagreb, p. 4. aljinović, d., kolar-jurkovšek, t. & jurkovšek, b. (2006): lower triassic shallow marine succession in gorski kotar region (external dinarides, croatia): lithofacies and conodont dating.− rivista ital. pal. stratigr., 112/1, 35−53. balaž, e. (1981): carboniferous gastropods of lika and velebit.− palaeont. jugosl., 26 (1980/3), 1−23, zagreb. basch, o. (1981): osnovna geološka karta sfrj 1:100000, list ivanićgrad l 33-81 [basic geologic map of sfry 1:100000, ivanić-grad sheet – in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd. geologia croatica 65/3geologia croatica 280 basch, o. (1983): osnovna geološka karta sfrj 1:100000, tumač za list ivanić-grad l 33-81 [basic geologic map of sfry 1:100000, geology of the ivanić-grad sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd, 66 p. bashforth, a.r., falcon-lang, h.j. & fielding, c.r. (2010): vegetation heterogeneity on a late pennsylvanian braided-river plain draining the variscan mountains, la magdalena coalfield, northwestern spain.− palaeogeogr. palaeoclimatol., palaeoecol., 292, 367−390 doi: 10.1016/j.palaco.2010.03.037 belak, m. (2009): parametamorfne stijene (paleozoik, ?trijas – pz, ?t) [parametamorphic rocks (palaeozoic, ?triassic – pz, ?tr) − in croatian].− in: velić, i. & vlahović, i. (eds.): explanatory text for geologic map of croatia 1: 300000. hrvatski geološki institut, 16−18. borojević šoštarić, s., palinkaš, l.a., strmić-palinkaš, s., bermanec, v., neubauer, f., spangenberg, j. & prochaska, w. (2009): origin of siderite mineralization in petrova and trgovska gora mts., nw dinarides.− miner. petrol., 97, 11−128. doi: 10.1007/s00710-009-0065-2 boyarina, n. (2010): late gzhelian pteridosperms with callipterid foliage of the donets basin, ukraine.− acta palaeontologica polonica, 55/2, 343−359. doi: 10.4202/app.2009.0020 brkić, m., jamičić, d. & pantić, n. (1974): carboniferous deposits in mount papuk (northeastern croatia).− geol. vjesnik, 27, 53−58. cleal, c.j., opluštil, s., thomas, b.a. & tenchov, y. (2011): pennsylvanian vegetation and climate in tropical variscan euramerica.− episodes, 34/1, 3−11. dimichele, w.a., gastaldo, r.a. & pfefferkorn, h.w. (2005): plant biodiversity partitioning in the late carboniferous and early permian and its implications for ecosystem assembly.− proceedings california acad. sci., 56, suppl. i/4, 32−49. đurđanović, ž. (1968): conodonten des unterdevons und unterkarbons westlich von dvor na uni (kroatien-jugoslawien).− geol. vjesnik, 21 (1967), 83−103. đurđanović, ž. (1973): about the paleozoic and the triassic of medvednica mountain and the area near dvor na uni on the basis of conodonts.− geol. vjesnik, 25 (1971), 29−51. fritz, a. & krainer, k. (2006): vegetationsgechichtliche und florenstratigraphische untersuchungen im oberkarbon und unterperm der ostund südalpen.− carinthia ii, 196/116, 93−120. geinitz, b. (1868): die fossil pflanzenreste aus dem schieferberge von tergove in croatien.− verh. geol. reichanst., 8, 165−167. grimani, i., šušnjar, m., milan, a., nikler, l., bukovac, j., crnolatac, i., šikić, d., grimani, i., vulić, ž. & blašković, i. (1970): osnovna geološka karta sfrj 1:100000, list crikvenica l33-102 [basic geologic map of sfry 1:100000, crikvenica sheet – in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd. grimani, i., šušnjar, m., bukovac, j., milan, a., nikler, l., crnolatac, i., šikić, d. & blašković, i. (1973): osnovna geološka karta sfrj 1:100000, tumač za list crikvenica l33-102 [basic geologic map of sfry 1:100000, geology of the crikvenica sheet – in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd, 47 p. gulyás-kis, cs. (2003): upper carboniferous flora from the mecsek mts (southern hungary) – summarized results.− acta geologica hungarica, 46/1, 115−125. herak, m. (1956): geologie des samoborer gebirges.− acta geol., 1, 49−73. herak, m. & škalec, d. (1967): kalkalgen im perm des samoborer gebirges.− geol. vjesnik, 20 (1966), 37−40. ivanović, a., sakač, k., marković, s., sokač, b., šušnjar, m., nikler, l. & šušnjara, a. (1973): osnovna geološka karta sfrj 1:100000, list obrovac l33-140 [basic geologic map of sfry 1:100000, obrovac sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd. ivanović, a., sakač, k., sokač, b. & vrsalović-carević, i. (1976): osnovna geološka karta sfrj 1:100000, tumač za list obrovac l33-140 [basic geologic map of sfry 1:100000, geol­ ogy of obrovac sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd, 61 p. jamičić, d. (1989): osnovna geološka karta sfrj 1:100000, list daruvar l33-95 [basic geologic map of sfry 1:100000, daruvar sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd. jamičić, d. & brkić, m. (1988): osnovna geološka karta sfrj 1:100000, list orahovica l33-96 [basic geologic map of sfry 1:100000, orahovica sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd. jamičić, d., brkić, m., crnko, j. & vragović, m. (1987): osnovna geološka karta sfrj 1:100000, tumač za list orahovica l3396 [basic geologic map of sfry 1:100000, geology of orahovica sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd, 72 p. jamičić, d., vragović, m. & matičec, d. (1989): osnovna geološka karta sfrj 1:100000, tumač za list daruvar l33-95 [ba­ sic geologic map of sfry 1:100000, geology of daruvar sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd, 63 p. jamičić, d. & crnko, j. (2009): hercinski semimetamorfni kompleks (devon, karbon, perm – d, c, p) [hercynian semimetamor­ phic complex (devonian, carboniferous, permian – d, c, p) – in cro ati an].− in: velić, i. & vlahović, i. (eds.): explanatory text for geologic map of croatia 1: 300000. hrvatski geološki institut, 19−20. jenko, k. (1944): geoložki rad na listu samobor [geology of samobor sheet – in croatian].− vjestnik hrv. geol. zavoda, 2/3, 19−23. jerinić, g., pamić, j., sremac, j. & španić, d. (1994): palynological and organic-petrographic data on very low and low grade metamorphic rocks in the slavonian mountains (northern croatia).− geol. croat., 47/2, 149−155. kochansky-devidé, v. (1955): karbonske i permske fuzulinidne foraminifere velebita i like i. opći dio i karbon [carboniferous and permian fusulinids of the velebit mt. and lika region. introduction and carboniferous − in croatian].− rad jugosl. akad., 305, 5−62, zagreb. kochansky-devidé, v. (1959): karbonske i permske fuzulinidne foraminifere velebita i like. donji perm [carboniferous and per­ mian fusulinids of the velebit mt. and lika region. early permian – in croatian ].− palaeont. jugosl., jugosl. akad., 3, 62 p. kochansky-devidé, v. (1970): die kalkalgen des karbons vom velebit-gebirge (moskovien und kassimovien).− palaeont. jugosl., 10, 32 p. kochansky-devidé, v. (1981): karbonische stromatoporoidea und bryozoa von markuševec in medvednica-gebirge.− geol. vjesnik, 34, 15−17. kochansky-devidé, v. & herak, m. (1960): on the carboniferous and permian dasycladaceae of yugoslavia.− geol. vjesnik, 13, 65−96. kochansky-devidé, v. & ramovš, a. (1966): zgornjekarbonski mikrofosili in stratigrafski razvoj v zahodni sloveniji (oberkarbonische mikrofossilien und stratigraphische entwicklung in den westkarawanken).− razprave – dissertationes, 9/7, 301−333. kostić-podgorska, v. (1955): oberkarbonische korallen von trgovska gora (croatien).− geol. vjesnik, 8−9 (1954–55), 115−121. kolar-jurkovšek, t. & jurkovšek, b. (2002): karbonski gozd. karbonske plasti z rastlinskimi fosili pri ljubljani. (carboniferous forest. carboniferous strata with plant fossils near ljubljana).− slovenian geol. survey and authors, 191 p. jasenka sremac: influence of terrestrial sedimentation in pennsylvanian rocks of croatia geologia croatica 281 kolar-jurkovšek, t. & jurkovšek, b. (2012): late carboniferous floras of slovenia – a review.− geol. croat., 65/3, 323-328. doi: 104154/gc.2012.21 laveine, j-p. (2005): the cyclopteris of laveineopteris (late carboniferous pteridosperm). fancies and facts: methodological and taxonomical implications.− revue de paléobiologie, 24/2, 403−487. merino-tomé, o., bahamonde, j.r., samankassou, e. & villa, e. (2009): the influence of terrestrial run off on marine biotic communities: an example from a thrust-top carbonate ramp (upper pennsylvanian foreland basin, picos de europa, nw spain).− palaeogeogr., palaeoclimat., palaeoecol., 278 (1−4), 1−23. doi: 10.1016/j.palaeo.2009.04.002 milanović, m. (1982): carboniferous microfossil associations from gorski kotar; hrvatsko zagorje and banija.− palaeont. jugosl., 28, 1−34. němejc, f. (1936): contribution to the knowledge of the carboniferous flora of the coal measures at the north-eastern foot of the velebit mountains (yougoslavia).− bull. int. acad. sci. boheme, 1−16. palinkaš, l.a., borojević šoštarić, s. & strmić palinkaš, s. (2008): metallogeny of the northwestern and central dinarides and southern tisia.− ore geology reviews, 34 (2008), 501−520. doi: 10.1016/j.oregeorev.2008.06.006 palinkaš, l.a., borojević šoštarić, s., strmić palinkaš, s., prochaska, w., spangenberg, j., cuna, s. & šinkovec, b. (2010): permian-polysulphide-siderite-barite-haematite deposit rude in samoborska gora mts., zagorje-mid-transdanubian zone of the internal dinarides.− geol. croat., 63/1, 93−115. doi: 104154/gc.2010.06 pamić, j. & jurković, i. (2002): paleozoic tectonostratigraphic units of the northwest and central dinarides and the adjoining south tisia.− int. j. earth. sci. (geol. rundsch.), 91, 538−554. pamić, j. & tomljenović, b. (1998): basic geological data from the croatian part of the zagorje-mid-transdanubian zone.− acta geol. hungarica, 41/4, 389−400. ramovš, a., hinterlechner-ravnik, a., kalenić, m., karamata, s., kochansky-devidé, v., krstić, b., kulenović, e., mirković, m., petkovsky, p., sremac, j. & temkova, v. (1990): stratigraphic correlation forms of the yugoslav paleozoic.− rend. soc. geol. it., 12 (1989), 359−383. rukavina, d. (1973): a contribution to the information about upper paleozoic bivalves of lika and the northeast foot of velebit (central croatia).− geol. vjesnik, 26, 319−323. salopek, m. (1942): o gornjem paleozoiku velebita u okolici brušana i baških oštarija [on the upper palaeozoic of the velebit mt. in the vicinity of brušane and baške oštarije – in croatian].− rad jazu., 274, 218−272. salopek, m. (1948): o gornjem paleozoiku sjeveroistočnog podnožja velebita i like [on the upper palaeozoic of the northeastern slope of the velebit mt. and lika region – in croatian].− rad jazu, 274, 75 p. salopek, m. (1949): gornji paleozoik u okolini mrzle vodice u gorskom kotaru [upper palaeozoic in the vicinity of mrzle vodice in gorski kotar region – in croatian].− ljetopis jugosl. akad., 55, 175−184. salopek, m. (1960): o gornjem paleozoiku u okolini mrzle vodice i crnog luga [on the upper palaeozoic of the vicinity of mrzle vodice and crni lug – in croatian].− acta geol., 2, 121−138. savić, d. & dozet, s. (1985a): osnovna geološka karta sfrj 1:100000, list daruvar l33-90 [basic geologic map of sfry 1:100000, daruvar sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd. savić, d. & dozet, s. (1985b): osnovna geološka karta sfrj 1:100000, list daruvar l33-90 [basic geologic map of sfry 1:100000, daruvar sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd, 66 p. simić, v. (1935): gornjokarbonski fosili iz like u hrvatskoj [late car­ boniferous fossils from lika in croatia – in serbian].− vesnik geol. inst. kralj. jugosl, 1/1, 141−145. sokač, b., bahun, s., velić, i. & galović, i. (1976): osnovna geološka karta sfrj 1:100000, tumač za list otočac l 33-115 [ba­ sic geologic map of sfry 1:100000, geology of otočac sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd, 44 p. sokač, b., nikler, l. & velić, i. & mamužić, p. (1974): osnovna geološka karta sfrj 1:100000, list gospić l 33-127 [basic geologic map of sfry 1:100000, gospić sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd. sokač, b., ščavničar, b. & velić, i. (1976a): osnovna geološka karta sfrj 1:100000, tumač za list gospić l 33-127 [basic geo­ logic map of sfry 1:100000, gospić sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd, 64 p. sokač, b., šušnjar, m., bukovac, j. & bahun, s. (1976b): osnovna geološka karta sfrj 1:100000, tumač za list udbina l33128 [basic geologic map of sfry 1:100000, geology of udbina sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd, 62 p. sremac, j. (2005): equatorial shelf of the palaeozoic supercontinent – cradle of the adriatic carbonate platform.− geol. croat., 58/1, 1−19. sremac, j. & aljinović, d. (1997): upper palaeozoic fossils from clastic sedimentary rocks in the gorski kotar region.− geol. croat., 50/2, 187−199. sremac, j. & mihajlović-pavlović, m. (1981): graptolites of mt. medvednica (zagrebačka gora).− rad jazu, 404, 65−68. stur d. (1868): fossile pflanzenreste aus dem schiefergebirge von tergove in croatien.− jahrb. geol. reichanst., 18/1, 131−138. šikić, k. (1995): geologija medvednice. paleozoik i trijas [geology of mt. medvednica. palaeozoic and triassic – in croatian].− in: šikić, k. (ed.): geološki vodič medvednice. inst. geol. istraž; industr. nafte d.d., naftaplin, 9−11. šikić, k. (2009): klastične i karbonatne naslage (devon, karbon – d, c) [clastic and carbonate deposits (devonian, carboniferous – d, c) – in croatian].– in: velić, i. & vlahović, i. (eds.): explanatory text for geologic map of croatia 1: 300.000. hrvatski geološki institut, 18−19. šikić, m., basch, o. & šimunić, a. (1978): osnovna geološka karta sfrj 1:100000, list zagreb l33-80 [basic geologic map of sfry 1:100000, zagreb sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd. šikić, m., basch, o. & šimunić, a. (1979): osnovna geološka karta sfrj 1:100000, tumač za list zagreb l33-80 [basic geologic map of sfry 1:100000, geology of zagreb sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd, 81 p. šparica, m. (2009): pretežito klastične naslage (karbon, perm – c, p) [dominantly clastic deposits (carboniferous, permian – c, p) – in croatian].− in: velić, i. & vlahović, i. (eds.): explanatory text for geologic map of croatia 1: 300.000. hrvatski geološki institut, 23−25. šušnjar, m., sokač, b., bahun, s., bukovac, j., nikler, l. & ivanović, a. (1973): osnovna geološka karta sfrj 1:100000, list udbina l33-128 [basic geologic map of sfry 1:100000, crikvenica sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd. tomljenović, b., csontos, l., márton, e. & márton, p. (2003): structural and palaeomagnetic data from the border zone between alps, dinarides and pannonian basin (medvednica and samoborsko gorje, croatia). implications for geodynamic evolution of the area.− ann. univ. sci. budap. rolando. eötvös nominatae, sectio geologica, 35, 120−122. geologia croatica 65/3geologia croatica 282 velić, i., šparica, m. & vlahović, i. (2009): klastične i karbonatne naslage (karbon, perm – c, p) [clastic and carbonate deposits (carboniferous, permian – c, p) – in croatian].– in: velić, i. & vlahović, i. (eds.): explanatory text for geologic map of croatia 1: 300000. hrvatski geološki institut, 20−23. velić, i. & vlahović, i. (2009): tumač geološke karte hrvatske 1: 300.000 [explanatory text for geologic map of croatia – in croatian].− hrvatski geološki institut, zagreb, 141 p. vozarova, a., ebner, f., kovacs, s., kräutner, h.-g., szederkenyi, t., krstić, b., sremac, j., aljinović, d., novak, m. & skaberne, d. (2009): late variscan (carboniferous to permian) environments in the circum pannonian region.– geol. carpath., 60/1, 71−104. doi: 10.2478/v10096-009-0002-7 zodrow, e.l., šimůnek, z., cleal, c.j., bek, j. & pšenička, j. (2006): taxonomic revision of the palaeozoic marattialean fern acitheca schimper.− rev. palaeobot. palynol., 138/3−4, 239−280. doi: 10.1016/j.revpaleo. 2006.01.007 manuscript received march 26, 2012 revised manuscript accepted july 27, 2012 available online october 30, 2012 geol. croat. 50/2 139141 1 1 zagreb 1997 professor milan herak on the occasion of his 80th birthday ivan gusler and vclimir kranjec2 milan herak was born on march 5th, 1917, in bra­ s ljcvica, in the area colloqu ially referred to as zumbe­ rak karst. he grew up in a large family , where good working habits were acquired carly in life, and where he benefited from family harmony and mutual support. in his lat er professional career, as a researcher, team leader, mentor or supervisor, these qualities aided hi s fostering of a stimulating, creative research environ­ ment. he finished second classical high school in za­ greb during which he did not commit himself to any profession. when he was selecting university ed uca­ tion, he followed his inclination toward research activi­ ty , which was olielted by the then philosophica l facu~ ity with a combination of several natural sc iences. as a student, herak was mainly interested in the botanical courses, whereas his close colleague radovan dom<lc was more strongly commited to geology, and according to their preferences they divided among themselves the obligations of the lecture notes. during his study, herak was selected as a demonstrator in thc department of geology and palacontology. this, toge­ the r with his part icipation in geological field research led by professor salopek, and successfully completed field work in lika, paklenica and later on mt. medved­ nica, resulted in geology, (which was not his primary desig nation), becoming his addiction and thus his pro­ fessional future. professor h erak used to comment " ... one has not to define his future vocation in the early youth". after he graduated (1941) , he received advance training in palaeontology in vienna where he obtained hi s ph.d. , which was based on th e palaeontolog ical study of triassic sponges under the guidance of profes­ sor julius pia, who was m that time the most outstand­ ing specialist for fossil algae. here, besides other things, he had to take nine examinations and to partici­ pate in the course of palaeontology lectured by kurt ehrenberg (the so n-inlaw of othenio abel). despite the fact that, at that time, abel's palaeobiology was based on neolamarkism, professor herak was not indui department of geology and palaeonto logy, fac ulty of sciences, university of zag reb, ul. kralja zvonimira 8, hr ioooo zagreb, croatia. 2 racuity of mining, gcology and petroleum engineering, university of zagreb, pi crollijcva 6, hr-l ocxxj zagreb, croatia. enced by this idea in his subscquent investigation s of foss il algae and particularly or the cave bear from krap­ ina, which was characteristically based on a population approach. although he was employed between 1943-1952 with the geological-palaeontological museum in zagreb, wherc he was also vcry ac tivc, professor h erak had already been engaged since 1949 with the universi ty of zagreb as a part-timc professor. initially, he taught the new introduccd courses of palaeobotany and palaeobi­ ology in the faculty of science, and lectured basic geo­ logy to student.s of civil engineering and geodesy of lhe then technical faculty. for both palaeobotany and pala­ eobiology he utilised his own research experience from his undergraduate and postgraduate training. in 1952 professor hcrak was appointed assistant professor of the then technical faculty, in hi s notes professor herak states that it was not an easy decision for him j because he had planned his future with the fac­ ulty of science, however, this employment was very useful for geosciences, as very soon herak founded the independent d epartme nt for geology and palaeonto­ logy. previously , in the mining division of {he techni­ cal facujty there only existed the department for mine­ ralogy and petrology. (headed by professor luka maric) and the department for coal geology and oil (led by professor franjo ozcgovic). this was quickly followed by the appointment of the lale dragutin sikic as herak's assistant. besides courses in fundamental geology, herak initially taught the new course in engi­ neering geology with hydrogeology. today, it is quite concievable that engi neering geo­ logy and hydrogeology are obligatory courses in all branches of geosciences, and a prerequisite for a coil­ temporarely educated geologist. however, in 1952, when professor herak commenced to lecture this cou­ rse , it was in fact named applied gcology with hydro­ geology. and now, according to his own statemem, although he has never been taught in such applicable courses, profcssor herak changcd the contcnt of "applied geology" into the "application of geology". this paper was presented at the scientific meeting ded icated to the 80th anniversary of the life of professor milan her ak, held on march 5th, 1997 in zagreb 14u at first glance, this lllay seem a trivial change, or just a semantic trick. however, there is an essen tial differ­ ence. pasteur once said: "there docs not exist a pure (or fundamental) science and the applied science, but there exist only the science and ils application, and both of them arc mutually related as the fruit tree and its fruits". although at thal time professor herak did not know pasteur's saying, he completely applied it. this shows ihe identical way of thinking of these two great human beings. herak had previously obtained practical experi­ ence in hydrogeology, first with the late josip poljak and later, and to a greater extent, in his individual work on the geological exploration related to the water accu­ mulation in karst areas. herak, on the basis of his own experience and addi­ tional contemplation of theoretical geological problems, which can have any reflection in practical application, produced comprehensive subject matter for a new cou­ rse . to be sure, the precise cons ideration of separate concrete problems of quantification, i.c., the measure­ ments, are nowadays obligatorily required, but without geological ideas in terms of what, where and why to measure, the quantification becomes and remains the purpose for itself. in another words, as professor herak used to say, the karst hydrogeology, including the mor­ phology, can be understood only if the geology and structure of the terrain are known. it means that the first approach in karst exploration must be tectogenetic and not purely "geomorphological" and descriptive, as was the case with earlier researchers. consequently, from 1952-1959, when professor herak left the technical faculty and accepted the pro­ fessor's position at the faculty of sciences, he was tea­ ching engineering geology with hydrogeology (besides courses in fundamental geology) in the technical facu­ lty, and palaeobotany in the faculty of sciences. it is hard to conceive two more heterogeneous courses, and even geoscientific disciplines, which can be successful­ ly realized by one person and teacher. very soon aner his appointment to the faculty of sciences, herak became the active chairman (19591974) of the department of geology and palaeontology of the faculty of sciences, and in 1960 he was elected full professor. he was cont in uously teaching in the technical faculty, as a part-time professor until the introduction of a younger successor. throughout hi s prevai ling geo logical occupation, professor milan herak has published about 220 differ­ ent bibliographic units, which include about 100 scien­ tific papers, 13 edi tions of text -books in geology and palaeonlology, the author's edit ion "general account of the earth", and the international hand book "karst", published by elsevier (1972). the thematic span of hi s papers is very broad and are equal ly distributed bet­ ween domestic and international journals. this broad field of vision is characteristic not only of his research and scientific act ivity but also of his teaching work. his teaching method re lies on bu ilding upon a good fou ndation of knowledge, adding specialist ljeologw lroatlgi :'lujl techniques in order to obtain results. knowing how 1o apply th e geology is the tool which we learned from him to utilise in understanding complex geological occurrences, and to show that they can be explained in a simple and understandable manner. he convinced us that field research must be based on a concept which should be checked by observations. when the geologi­ cal processes do not fit into the concept and thus cannot be explained, then the concept should be changed; this was professor herak's guiding principle. generally, and as a rule, at undergraduate level pro­ fessor herak was lecturing standard courses (e.g. gener­ al geology, stratigraphy), gradually passing them to the younger teachers as he founded new courses, as exem­ plified by karst geo logy. before his professorship in the technical faculty, professor herak, together with late professor miroslav tajder, wrote the geological part or their joint universi­ ty text-book "petrography and geology", that was inten­ ded for students of agriculture and forestry. this hand­ book ran through four editions (1951,1959,1966 ancl 1972), further editions were only prevented by profes­ sor tajder's decease. also during his employment with the museum, professor herak started to write a hand­ book on palaeobotany , bccause he took too seriously the official suggestion, prevai lcnt at that time, that each course shou ld be covered by a correspond ing text-book. however, whatever the reasons, after the initial publish­ ing difficulties with "skolska knj iga", this book ran for two edit ions (1953 and 1963) and the book was also received in ljubljana and belgrade. the strongest inllu­ enee for many generations of students of geology was, and sti ll is today, though to a lesser extent, professor herak's comprehens ive book on the whole subject of geology (structure, geodynamics, stra tigraph y and regional geology of the earth), which ran through fiv e edi tions (1960, 1973, 1984, 1987, 1990). this was, and still is, for the time being, the first and the only compre­ hensive textand handbook in geology in the universi­ ty of zagreb. it would be desirable and in the interests of geology, as an integral natural science, that we have more textbooks for separate geological disciplines, and professor herak' s book will always represent a " li ght­ house", in this direction, the first step which "broke the ice". (this refers to the geology in the stric t sense, for there are text-books on mineralogy, petrography, etc.) in modern university education more and more sig­ nificance is focused on post-g raduate stud ies. this is guite understandable due to the tremendous progress and branching of the natural sciences, incjuding geolo­ gy. professor herak was the fo under and the first leader of post-graduate study in geology at the university of zagreb and he is still included in its act ivity. perhaps his most important , and most lastin g (or even "sclfreproducing") contribution to geology in cro­ atia, is professor herak 's act ivi ty in guiding and push­ ing forward young scientists. he was the mentor for 16 doctoral theses and many more masters theses. the range of his students covered all branches of geology, from palaeontology to hydrogeology. thus he set firm foundations for continuous activity in numerous geo­ logical disciplines, which he initiated by his own rese­ arch. 11 should be mentioned, as a fact of special impor­ tance, that lierak's doctor's and master's candidates caille not only from croatia but also 5 or 6 of them from bosnia and i iercegovina, which considerably pro­ moted both herak's personal influence and the influ­ ence of zagreb geological school in that country. for his many-faceted and very fruitful activity, pro­ fessor i ierak was honoured with numerous credits . he is a correspondent member (from 1963) and a full me­ mber of the croatian academy of sciences and arts. he was also its viceprcsident (j 975-1978), the secretary of its department for natural scicnces (1986-1988), the member of its presidency, editor-in-chief of its journals ·'acta geologica" and "karst of yugoslavia" and the leader of its committee for karst and committee for geotectonics. he is also a member of the austr ian (sin­ ce 1977), and sloven ian academy (since 1977), and he was also a member of the serbian academy of sciences until 1991, wilen he cancel led this membership. he is a member of the geological society of croatia, was its first secretary and afterwards its president and honorary membcr. he is a member of numerous international societies. ile was awarded the "rueter boskovic" prize (1968), thc prize for the life deed (1976) and the com­ memorative medal of zagreb city (j 965). i-ie was awarded by the orden of work with a go lden wreath (l96l) and by the orden for the working people mcrit with golden star (1986). as a symbol of the significance of his scientific and research activity, numerous authors honoured professor herak by the nomination of new taxa based on his name. these are for the most part fossil calcareous algae, i.c. in hi s greatest and most easily recognizable palaeontological research activity. the croatian geologists, including his numerolls students, organized a scientific meeting on march 5th, 1997, on the 80th anniversary or his lire, paying tribute to professor herak and giving him credit for his tcach ­ ing, professional, and scientific activity. as a lasting record of this even t, the content of the scientifi c meet­ li1g is now issued as a separate volume of geologia croatic<1. geologia croaticageologia croatica ab stra ct the main purpose of this research is to determine the quality of ground water in wadi addawasir by the assessment of 12 chemical parameters: ph, ec, eh, tds, th, ca2+, cl–, hco3 –, mg2+, na+, no3 –, and so4 2–. statistical analyses were carried out using descriptive statistics, histograms, and normal quantile plots. the spss 15 software package (spss inc. 2006) and jmpin (version 4.0.4) were used as the main statistical software. many locations within the study area show thatf ph, ec, hco3 – and na+ values exceed permissible limits. the concentration of anions is in the order so4 2–>cl–>hco3 –. some of the analyzed parameters approach a normal distribution, as both their skewness and kurtoses are close to zero. however, skewness for some parameters such as mg2+ and hco3 – is high. kurtosis for most of the elements varies from moderate to low. only ph, hco3 – and so4 2– have kurtoses. both the results of cluster tree and geochemical features of variables could be generally classifi ed into three main groups. group 1 is comprised of na and so4 2–. the relationships within this group are strong. group 2 consisted of mg2+, no3 –, ph, hco3 –, and ca2+. the fact that this group has a close relationship with group 1 demonstrates that the increase in the concentration of some elements could be the same. group 3 is comprised of th, cl–, eh, and ec. keywords: hydrochemistry, geostatistics, histograms, normal quantile plots, wadi addawasir, saudi arabia geologia croatica 67/3 207–216 6 figs. 3 tabs. zagreb 2014 statistical characterization of the hydrochemical data’s of groundwater in the arid land of wadi addawasir area, saudi arabia: a probabilistic assessment  1yousef nazzal*, 1nassir s. n. al-arifi , 2h.a. kishawy, 1khaled m. al-kahtany and 1awad alshmrani 1 department of geology and geophysics, king saud university, po box 2455, riyadh 11451, saudi arabia 2 faculty of engineering and applied science, university of ontario institute of technology, 2000 simcoe street north, oshawa, ontario, l1h 7k4, canada doi: 10.4154/gc.2014.15 haken (2013). when limited trace element data are available, geochemical environmental scientists are often requested to evaluate the character and quality of groundwater. if the distribution of trace elements in groundwater is known, then observed data could be used to easily differentiate between representative or anomalous groundwater compositions. however, because characterizing a groundwater system is diffi cult and expensive, a representative benchmark of known element distributions to categorize observed data is rarely available. as a result, effective evaluation of concentrations of observed trace elements might be challenging 1. introduction the chemical composition of water is an important factor in determining its healthy condition for the various applications that support human life. the quality of groundwater is governed by many factors, such as soil characteristics, circulation pattern of groundwater through different rock types, topography of the region, saline water intrusion in coastal areas, and fi nally human activities, reghunath et al. (2002). in many countries, for instance saudi arabia, groundwater is the unique source of freshwater to satisfy domestic uses as well as industrial and agricultural demands geologia croatica 67/3geologia croatica 208 and require further investigation, newcomb, w.d. & rim stidt, j.d. (2002). probabilistic methods are well suited for describing the complex distributions of trace elements in groundwater. these techniques rely on large sample populations which can satisfactorily represent the system of groundwater to be studi ed. the costs associated with sample collection and laboratory analyses to establish large sample populations may impose a barrier to the application of probabilistic methods. public domain data resources, such as storet, are appropriate databases where large environmental data can be accessed at low cost, epa (2001). however, little or no data analysis capabilities are provided in the public domain sources. moreover, trace element sample populations are often censored at multiple reporting limits (rls), depending upon variations in laboratory analysis methodology and techniques. the use of data analysis techniques, as described by helsel (1990), and helsel, d.r. & hirsch, r.m. (1992), for multiple-censored sample populations can be used to extract salient information from raw trace element data. the present study deals with the assessment of the major groundwater parameters data. to achieve this, histograms and normal quantile plots were used to define subpopulations in the water samples. this work provides a rapid, cost-effective screening tool for evaluating groundwater quality based on the observed element concentration data. normal quantile plots yield significant detail on the behavior of subpopulations at both the high and low end of the frequency spectrum, as well as those having a central tendency. having been utilized in data mining in space research, normal quantile plots demonstrate their strong capability in explaining clustered properties even in very large data sets (e.g., manku et al., 1999). newcomb, w.d. & rimstidt, j.d. (2002) used the probability distribution of trace elements in very large numbers of ground water samples in the storet dafigure 1: a – sampling locations and geological map of wadi addawasir in saudi arabia; b – summary stratigraphic succession of the wajid sandstone in the region (after kellong et al., 1986). a) b) nazzal et al.: statistical characterization of the hydrochemical data’s of groundwater in the arid land of wadi addawasir area, saudi arabia ... geologia croatica 209 tabase, u.s. environmental protection agency (2002). major research and discoveries related to wajid sandstone hydrogeology, geology, and hydrochemistry of the study area have been published by dabbag (1981), dabbag, m.e & rogers, j.j.w. (1983), mosharif (1989), mosharif & el-hitti, a. (1989), stump, t.e.& von der eem, j.g.(1994), italconsult (1969), and alfaifi, h.j.a. (2005). 2. study area 2.1. descriptions of the study area the study area is situated within wadi addawasir. it is located between latitudes 19° 30ʹ 00ʺ n, 21° 00ʹ 00ʺ and longitudes 44° 00ʹ 00ʺ e, 46° 30ʹ 00ʺ 650 km south of riyadh (fig. 1a).the study area is very important in saudi arabia from an agricultural point of view. the annual average temperature in the area is about 29 °c, the maximum average temperature is 43 °c, and the minimum average temperature is 6 °c. the mean temperature during summer is 35 °c and june is the hottest month of the year. the annual average relative humidity is about 24% and it is more than 70% during winter. the average rainfall is 37.6 mm/year. maximum rainfall in march includes the mediterranean storm effect on winter rainfall, al-faifi, h.j.a. (2005). 2.2. geological setting the study area lies within the wadi tathlith quadrangle, which covers a surface area of 8902 km2 of the southern najd province of saudi arabia. about two thirds of the quadrangle is underlain by an assemblage of stratified rock overlying the oldest crystalline, metamorphosed, precambrian basement rocks of the arabian shield, much of it comprising an almost flat pediment surface. almost horizontally bedded phanerozoic sedimentary rocks underlie the remaining part of the wadi tathlith quadrangle in the southwest. in the study area, the phanerozoic rocks lie unconformably on the proterozoic of the arabian shield. the contact is not clearly exposed anywhere in the wadi tathlith quadrangle, and is commonly concealed by debris from the poorly consolidated basal conglomerate of the wajid sandstone. the wajid formation, which is one of the important geological formations in the study area, is divided into four members from bottom to top: dibsiyah member, sanamah member, khusayyan member, and juwayl member (fig. 1a, and b), al-faifi, h.j.a. (2005). 2.3. hydrogeological setting the wjid aquifer is considered to be one of the most important hydrostratigraphic units in the kingdom of saudi arabia. it is only to the east that there remain any doubts as to its extent. the depth of the aquifer, which reaches 480 metres, has made it impossible to detect the aquifer east of longitude 45 35 00 e. the unconfined part of the aquifer, in and near the outcrop zone of the wajid formation, is very extensive. it can be followed from the south bank of wadi addawasir to the yemen border in the south. the unconfined part of the aquifer seems to be absent to the north of wadi addawasir. the confined part of the aquifer is more extensive. the border between the unconfined and confined conditions roughly coincides with the western limit of the khuff formation at outcrop. the presence of the confined wajid aquifer has been confirmed over an area of 12000 km2 in the wadi addawasir region. however, it is reasonable to suppose that it continues for a considerable distance to the east of the sulayyil-wadi hinw, al-faifi, h.j.a. (2005). 3. materials and methods a total of 253 samples of groundwater were collected (each from a different water well location) in the wadi addawasir, saudi arabia, in the period between january to june 2013 (fig. 1). these wells are used for irrigation and public supply purposes. water depth ranges between 450–472 m, well casing is 269–278 m, screen is open.the pumps are installed in the wells and the samples collected directly from the well during pumping, al-faifi, h.j.a. (2005). samples were collected in 1 litre capacity polyethylene bottles, which were rinsed with well water prior to filling in order to minimize the chance of contamination. the sample preservation and applied analytical techniques were in accordance with the standard methods from the american public health association (apha, 1995). unstable parameters, such as hydrogen ion concentration (ph), total dissolved solids (tds) and electrical conductivity (ec), were determined at the sampling sites by means of a ph-meter, a portable ec-meter and a tds-meter (hanna instruments, michigan, usa). the sodium (na+), potassium (k+), magnesium (mg2+), and calcium (ca2+) ions were determined by an atomic absorption spectrophotometer (aas). bicarbonate (hco3 –) and chloride (cl–) were analyzed by volumetric methods. sulfate (so4 2–) was estimated by the colorimetric and turbidimetric methods. silicon dioxide (sio2 2–) was calorimetrically analyzed by the ammonium molybdate method. nitrate (no3 –) was measured by ionic chromatography. for the present study, statistical analyses were carried out using descriptive statistics, histograms, and normal quantile plots. the spss 15 packages (spss inc. 2006) and jmpin (version 4.0.4) were used as the main statistical software. histograms were used to analyze the data distribution. they are the appropriate tools for displaying frequency distributions and rely on dividing the data into classes (or bins). the data, following a normal distribution, will show a symmetric bell-shaped histogram, where a tail towards high values implies that the data are positively skewed. histograms provide visual approximations to distributions such as the bell shape of a normal distribution, but they have some limitations. the number of bins affects the shape of the curve where this number can be determined by the software. a curve representing the normal distribution, corresponding to the mean and standard deviation of the data set, is superimposed on the histogram for the purpose of comparison. extreme values occur at the high end, which are separated and identified as outliers in order to show the major tendency of the data. the limitations of the histograms are offset by normal quantile plots. geologia croatica 67/3geologia croatica 210 the normal quantile plot is a graph for each interval variable, which is useful for visualizing the extent to which the variable is normally distributed. if a variable is normal, the normal quantile plot is a diagonal straight line. this plot is also referred to as a theoretical quantile-quantile plot or q–q plot. normal quantile-quantile (q–q) plots are created by plotting observed values of a variable against the corresponding normal quantiles. display of data is done by plotting the normal quantiles (or scores) of the standard normal distribution on the y-axis with values usually between −4 to 4, and the variable under study on the x-axis (fig. 2). the kolmogorov–smirnov (k–s) test measures the degree to which a given data set follows a specific theoretical distribution (such as normal, uniform, or poisson). the statistical test of k–s is based on the largest absolute difference between the observed and the theoretical cumulative distribution functions. the k–s test assumes that the parameters (e.g., mean and standard deviation) of the test distribution are specified in advance, whereas the lilliefors correction for the k–s test is applied when means and variances are not known and must be estimated from the data. results were obtained for k–s test values by the spss statistical software, which automatically utilized the lillierfos correction. if the p-value reported is less than 0.05 (or some other alpha), then the distribution is not normal, sall, j. & lehman, a. (1996). therefore it is useful to use the normal quantile plot to help assess the lack of normality in the distribution. the authors therefore used the k–s test to minimize the effect of outlier populations for many of the elements. during comparison studies, discrepant results were obtained for k–s test values performed by spss and s-plus statistical software. the problem was resolved when it was found that the k–s results obtained with the s-plus application automatically utilized the lilliefors correction. for comparison, the lilliefors significance correction for the k–s test using spss was also applied. this method was best applied by zhang et al. (2008).the raw data were stored in a dbase file (dbf format), and basic calculations were performed using microsoft excel. most of the statistical calculations were accomplished with spss software (version 11.0), while sampling location maps were produced with arcview gis software (version 3.3). 4. results and discussion 4.1. general chemistry table 1 shows the statistical summary of selected physicochemical parameters. the ph values obtained from the analytical procedures indicates an alkaline nature for some of the studied water samples, where the maximum value of 9.08 and a minimum value of 5.56 have been recorded, with a mean value of 7.4. higher electric conductivity (ec) values (i. e., between 577.7 to 12170 µs/cm) have been observed in the study area, whereas the hco3 – values ranged between 0.11 to 339 mg/l. many locations show higher than the permissible values of 22–26 mg/l, (gulf countries committee standardization organization guidelines 2008). mg2+ values range between 0.16– 1359 mg/l, tds between 17.8–7880 mg/l, no3 – 6.04–2016 mg/l, and ca2+ 6.3–979.5 mg/l. as a dominant constituent, the anion concentration pattern is in the order of so4 2–>cl– >hco3 –. in the case of cations, the observed range of na+ has been placed between 0.21 to 1648.4 mg/l, which shows 12 locations in the northeastern part of the study area exceed the permissible limit of 200 mg/l, gccsog (2008). the possible sources of mg in the study area are igneous rocks, primarily ferromagnesian minerals like olivine, pyroxenes, amphiboles, and dark colored micas. also within metamorphic rocks, magnesium occurs in minerals such as chlorite, montmorillonite, and serpentine. in sedimentary environments, magnesium occurs as magnesite, dolomite and other carbonates, sometimes mixed with calcium carbonate. dolomite contains calcium and magnesium in equal amounts. most groundwater contains relatively small amounts of mg2+, except where they have been in contact with dolomite (amounts of ca2+ and mg2+ about the same), or with mg2+ – rich evaporates that could cause mg2+ to become the dominant cation in the groundwater. sodium is primarily derived from feldspars in igneous rock and its weathering products (clay minerals) in other material. shale and clay layers often yield water with relatively high sodium contents. other sources of sodium are leachate and deep percolation water from the upper soil layers (including atmospheric precipitation that has been subject to concentration effects), and contamination of groundwater by salty connate water or water of marine origin. brines and other salty waters which usually occur at great depths contain large amounts of sodium. primary sources of chloride in groundwater are evaporites, salty connate water, and marine water. igneous rock materials contribute little chloride. groundwaters containing significant amounts of chloride also tend to have high amounts of sodium, indicating the possibility of contact with water of marine origin. leaching of chlorides that have accumulated in upper soil layers may be a significant chloride source in dry climates. the recommended maximum figure 2: histogram and normal quantile diagram of study area. nazzal et al.: statistical characterization of the hydrochemical data’s of groundwater in the arid land of wadi addawasir area, saudi arabia ... geologia croatica 211 concentration for chloride in drinking water is 250 mg/1, primarily for reasons of taste. sulfate is formed by oxidation of pyrite and other sulfides widely distributed in igneous and sedimentary rocks. the most important sulfate deposits are found in evaporite sediments (gypsum, anhydrite, sodium sulfate). in arid regions, leaching of sulfate from the upper soil layers may also be significant, causing sulfate to be the principal anion of the underlying groundwater. sulfate concentrations in drinking water should not exceed 250 mg/1 because the water will have a bitter taste and can produce laxative effects at higher levels. factors that govern the concentration of various elements in the groundwater of the study area are the climate of the area, chemical composition of the water and the presence of accessory minerals in the rocks through which the groundwater is circulating. the high salinity particularly with in agricultural areas envisages anthropogenic influence. a variety of chemical fertilizers used for agricultural growth may enter into the groundwater system through return water. over exploitation of groundwater in the study area causes groundwater decline which may also affect its quality, alfaifi, h.j.a. (2005). thus, anthropogenic activities in the study area are also considered as potential factors in groundwater quality. industrial sources, including for example the production of glass, ceramics, electronics, steel and aluminum, processing pesticide and fertilizers and untreated waste water, together with agricultural activities are all considered as important anthropogenic sources for various elements in the study area. agricultural and industrial developments place huge demands on precious water resources. there has been significant over-exploitation of water resources resulting in large cones of depression. with the pumping rate of 1800 usg/min, drawdown after 20 years equals 43m. the predicted drawdown after 40 years and 60 years may reach to 90 m and 141m, respectively, al-faifi, h.j.a. (2005). 4.2. basic statistics the basic statistics (maximum, minimum, percentiles, mean, median, and standard deviation) for the data are shown in table 1. percentages are variable for all of the parameters in the study area; e.g., mg2+ varies between 0.16 and 1359.9 mg/l. the shape parameters (skewness and kurtosis) are also calculated and listed in table 2. some of the analyzed parameters approach a normal distribution, as both their skewness and kurtosis reach close to 0. skewness for some elements is high; e.g., mg2+ shows a high value of 4.51. others such as hco3 – have a much lower level of skewness. some parameters are characterized by high kurtosis values; mg2+ shows a high value of 29.02, which may be due to a large number of low value samples compared to the wide data range associated with the outliers. parameters such as hco3 – also have fairly low kurtosis, with the fact that these values are more evenly distributed within the data ranges. skewness measures the presence of a tail deviating from a normal distribution (0) toward lower values (negative skewness) or higher values (positive skewness). for the raw data sets, the skewness for the other parameters are positive, many of which are high (mg2+).this confirms the strongly skewed distributions displayed in the histograms and normal q–q plots. kurtosis refers to the “fatness” of the tails in statistical plots, where positive kurtosis denotes peakedness while a negative value represents a “flat” distribution. the kurtosis for most parameters is moderate to low. high positive kurtosis shows that very high values in the data are rare, presumably associated with rare processes such as mineralization. only ph, hco3 – and so4 2+ have a fairly small kurtosis, showing that these values are more evenly distributed within the data ranges, and that special concentration of these parameters is rare. logarithmic transformation tends to move both skewness and kurtosis for most parameters towards normality, i.e., closer to 0. another feature of the logarithmic transformation is that most of the transformed data sets have negative skewness values showing that the log-transformation has over-transformed the data. 4.3. histograms and normal quantile diagrams the probabilistic display delineates discrete populations that have genetic or other affinities as line segments showing changes in slope (i.e., “kinks”). the observed distributions significantly differ from the synthetic distributions modeled by sinclair, a.j. (1976) and zhang et al. (2008) for chemical distributions. it appeared that these pioneering authors have superimposed different types of distributions having the same concentration range, which yielded curved chan ges in the slope. the present data include elemental distributions with substantial overlap and curvatures. in fact, notable features include the prominent role of line segments showing sharp angular change. such features require largely discrete chemical subpopulations. histograms of data are shown in figure 3. as can be seen, some parameters have high values, which are reflected in the histograms by data being located on the left of the diagram. these extreme values are well visualized on the normal quantile diagrams, and they are identified as outliers. some parameters have values below or close to the detection limits (e.g., na+ and so4 2+), resulting in high frequencies for the lowest value group, near the limit of detection. the frequency distributions of some of the parameters are positively skewed and include some very high values. some extreme values (eh, cl–, mg2+, na+, and no3 –) appear to be separated from the majority of the samples, and do not appear to be part of a continuous distribution (e.g., figure 3, table 1). these extreme values might be regarded as evidence of particular natural or anthropogenic processes. the normal quantile diagrams for the data are shown in figure 4. straight-line segments are observed for some parameters including hco3 –. samples below the detection limit form the vertical line on the left side of the diagram (e.g., na+ and so4 2–). most of the parameters depart from normality towards the highest values, located on the right side of the straight normal distribution line. the result is referred to as the positively skewed or convex distribution feature for most elements. most of the parameters demonstrate some form of convex shapes; they are composed of multiple geochemical families and have closer to log-normal distrigeologia croatica 67/3geologia croatica 212 butions. the diagrams provide useful information for outlier detection. many single samples are separated from the distribution curve. the diagrams indicate mixtures of populations or geochemical families by identified changes in the slope for many parameters. most elements have high values, which are well visualized in normal quantile diagrams (fig. 4). the high concentrations for ca2+, cl–, mg2+, na+, no3 – and so4 2– show a sharp reduction in the slope at high concentration values. these samples may be influenced by natural or anthropogenic particular processes. most parameters show a closer approach to normality with some departures from normality occurring in the highest values, located on the right side of the straight normal distribution line. 4.4. correlation coefficient the correlation coefficient is presented in matrix form in table 3, which shows the pearson product-moment correlation coefficients. the matrix contains 12 variables, and summarizes the strength of the linear relationships between each pair of variables. if there is an exact linear relationship between two variables then the correlation is 1 or –1 depending on whether the variables are positively or negatively related. if there is no linear relationship, the correlation tends toward zero. a finding is described as “statistically significant” when the probability is less than 0.05 (p<0.05) and as “highly statistically significant” when p is less than 0.01 (p<0.01). if the probability value is greater than 0.05 (p > 0.05), the coefficient of correlation is not significant. most of the metal pairs exhibit positive relationships (except for eh, ec, mg2+, and no3 –). however, only a few of these correlations are significant at the 0.05 level (2-tailed), while the majority of them are significant at the 0.01 level (2-tailed). the parameters showing significantly higher positive correlation are: tds with ec; th and ec, tds; ca2+ and ec, tds, th; cl– and ec, tds, th, ca2+; mg2+ and ec; na+ and ec, tds, th, ca2+, cl–; no3 – and mg2+; so4 2– and ec, tds, th, ca2+, cl–, na+. table 1: percentiles of the variables of groundwater at wadi addawasir in saudi arabia (ec in [µs/cm]; eh in mv; chemical parameters are in mg/l). minimum 5% 10% 25% 50% 75% 90% 95% maximum mean s.d ph 5.46 6.83 7.04 7.22 7.45 7.64 8.04 8.52 9.08 7.48 0.46 ec 3.5 577 828 1028 1520 2700 3672 5380 1217 2119 1830 eh –206 –183 –117 –42 –19 623 1850 2018 7490 424 931 tds 17.8 172 218 464 784 1300 2282 3136 7880 1096 1119 th 13.5 48 61 143 315 588 920 1228 3944 440 497 ca2+ 6.3 14 18 30 89 172 278 366 979 127 135 cl– 5.2 94 110 151 180 356 721 1164 3793 349 464 hco3 – 0.11 6.15 13 50 128 168 203 236 339 117 73 mg2+ 0.16 12 17 26 46 96 248 363 1359 97 146 na+ 0.21 2.71 5.6 10 93 189 345 494 1648 149 226 no3 – 0.04 2.01 5.62 27 108 170 418.4 543 2016 147 201 so4 2– 0.01 0.1 0.19 0.43 156 272 507 633 1785 202 261 figure 3: histograms of the data set (a normal distribution curve for all the values is superimposed for comparison; ec in [µs/cm]; chemical parameters are in mg/l). nazzal et al.: statistical characterization of the hydrochemical data’s of groundwater in the arid land of wadi addawasir area, saudi arabia ... geologia croatica 213 the reason for this is the observed correlation for the various parameters based on the geochemical behaviour of the chemical species and /or the possible anthropogenic inputs to the water. therefore, the concentration of various parameters in groundwater is related to lithology and relies on the distance from the alteration areas, climate of the area, and chemistry of the water and the presence of accessory minerals of the rocks through which the groundwater is circulating. 4.5. scatter diagrams matrix correlation scatter diagrams help to visualize the correlations. scatter diagrams of each pair of variables are display ed figure 4: normal quantile plots for the data set (the normal quantiles are plotted on the y-axis; the observed values are plotted on the x-axis ec in [µs/cm]; chemical parameters are in mg/l). table 2: skewness, kurtosis in the data sets with results of kolmogorov-smirnov test.   raw variables log-raw variables parameter skewness kurtosis k-s p skewness kurtosis k-s p ph 0.5 2.39 0.000 0.14 2.98 0.000 ec 2.92 10.75 0.000 –1.38 13.05 0.000 tds 2.99 11.99 0.000 –0.37 0.91 0.000 th 3.38 16.66 0.000 –0.21 –0.43 0.000 ca2+ 2.81 11.41 0.000 –0.22 –0.56 0.000 cl– 4.27 23.12 0.000 –0.14 3.29 0.000 hco3 – 0.16 –0.52 0.000 –1.45 1.57 0.000 mg2+ 4.51 29.02 0.000 0.3 0.53 0.001 na+ 3.63 16.95 0.000 –0.3 –0.94 0.000 no3 – 4.14 28.47 0.000 –0.74 0.05 0.000 so4 2– 2.58 9.59 0.000 –0.46 –1.59 0.000 geologia croatica 67/3geologia croatica 214 table 3: correlation coefficients between the variables of groundwater at wadi addawasir in saudi arabia. ph ec eh tds th ca2+ ca2+ ca2+ ca2+ ca2+ ca2+ ca2+ ph 1                       ec –0.10 1                     eh –0.31 0.35 1                   tds 0.03 0.89 –0.09 1                 th 0.06 0.79 –0.21 0.94 1               ca2+ 0.00 0.79 –0.18 0.93 0.97 1             cl– 0.04 0.80 –0.21 0.95 0.92 0.89 1           hco3 – 0.25 0.08 –0.44 0.27 0.34 0.30 0.16 1         mg2+ –0.21 0.61 0.92 0.21 0.11 0.11 0.08 –0.26 1       na+ 0.09 0.74 –0.31 0.93 0.84 0.81 0.93 0.30 –0.04 1     no3 – –0.25 0.35 0.85 0.00 –0.11 –0.06 –0.13 –0.31 0.81 –0.22 1   so4 2– 0.09 0.66 –0.39 0.88 0.86 0.86 0.84 0.41 –0.11 0.92 –0.28 1 figure 5: scatter matrix plot for selected elements in analysed groundwater samples from the study area. nazzal et al.: statistical characterization of the hydrochemical data’s of groundwater in the arid land of wadi addawasir area, saudi arabia ... geologia croatica 215 in a matrix arrangement. a 95% bivariate normal density ellipse is imposed on each scatter diagram. if the variables are bivariate normally distributed, this ellipse encloses approximately 95% of the points (when the number of points is high). the strong correlation of the variables is seen by collapsing the ellipse along the diagonal axis. if the ellipse is fairly round and is not diagonally oriented, the variables are uncorrelated (fig. 5). to better visualize multiple relationships between the variables, a scatter matrix plot was produced (fig. 5) for the 12 variables, showing the best relationship in the cluster tree (fig. 6).in this plot, each cell shows the scatter between the variables in the corresponding row and column. a histogram for each variable was also provided in the diagonal cells where the variables for the corresponding row and column are the same. the histogram is shown separately in figure 3. to some extent, a good correlation between all 12 variables of ph, ec, eh, tds, th, ca2+, cl–, hco3 –, mg2+, na+, no3 –, and so4 2– was illustrated. the best correlation exists between na and so4 2–. relative correlations were observed for the variables tds, th, and ca2+, while the scatter plots between hco3 – and other variables were also relatively noisy. the results were in line with the cluster tree. 4.6. hierarchical cluster analysis (hca) the hierarchical cluster analysis (hca) seeks to identify homogeneous subgroups of cases in a population and to identify a set of groups which both minimize within-group variation and maximize between-group variation. one of the general approaches to cluster analysis is hierarchical clustering. the product of this approach is a dendrogram (fig. 6).also called tree diagrams, these show the relative size of the proximity coefficients at which cases were combined. in the present study, the euclidean distance is selected as the measured distance. the sampling sites with significant similarity are first grouped. following this, groups of samples are joined with a linkage rule, and the steps are repeated until all observations are classified. ward’s method has been successfully applied here to form clusters that are more or less homogenous and geochemically distinct from other clusters (batayneh, a. & zumlot, t. 2012; cloutier et al., 2008). it was also found that using the euclidean distance as a distance measure, and ward’s method as a linkage rule, produced the most distinctive groups. however, taking both the results of the cluster tree and geochemical features of variables into consideration, they could be generally classified into three main groups. group 1 comprised na+ and so4 2–. the relationship within this group is strong. group 2 consisted of mg2+, no3 –, ph, hco3 –, and ca2+. the fact that this group has a close relationship with group 1 demonstrates that the increase in the concentration of some elements could be the same. group 3 comprised th, cl–, eh, ec, and tds. 5. conclusions hydrochemical variable concentrations dominantly determine the overall quality and characteristics of groundwater. chemical parameters in groundwater are derived from both natural and anthropogenic sources. complex processes govern the distribution of chemical elements in groundwater. sophisticated data analysis techniques are required to effectively interpret chemical data. probabilistic data analysis techniques provide an enhanced data analysis capability for complicated chemical parameter distributions in groundwater. the results of this work suggest that chemical parameter data are approximately log-normally distributed, as both their skewness and kurtosis values are close to 0. the study shows that most of the metal pairs exhibit positive relationships (except for eh, ec, mg2+, and no3 –). the parameters showing significantly higher positive correlations are: tds with ec; th and ec, tds; ca2+ and ec, tds, th; cl– and ec, tds, th, ca2+; mg2+ and ec; na+ and ec, tds, th, ca2+, cl–; no3 – and mg2+; so4 2– and ec, tds, th, ca2+, cl–, na+. the cluster tree shows that they could be generally classified into three main groups. group 1 comprised na+ and so4 2–. the relationship within this group is strong. group 2 consists of mg2+, no3 –, ph, hco3 –, and ca2+. the fact that this group has a close relationship with group 1 defigure 6: dendrogram resulting from ward’s method of hierarchical cluster analysis for the 12 variables. geologia croatica 67/3geologia croatica 216 monstrates that the increase in the concentration to some elements could be the same. group 3 comprised th, cl–, eh, ec, and tds. some recommendation may considered here as follows: – a groundwater chemical analysis study should be conducted periodically and a solute transport model is recommended to monitor future deterioration of the water quality. – well drilling is one of the major problems in the study area, and there should be control on this factor. recommend the growth of crops that have a low demand for water to the agriculture industry. – irrigation systems must be changed to modern irrigation ones. should some of these problematic factors have been men tioned above in the body of the report, saying why they are an issue rather than just dropping them in here at the end? no conclusion or recommendations should really contain new information that hasn’t been mentioned before e.g. what high demand crops are grown and what are the problematic irrigation systems – how and why is well drilling an issue? i am assuming you mean small wells mentioned at the beginning for irrigation? it is much more informative for the reader if you discuss these issues before you make recommendations against them. acknowledgment this project was supported by nstip strategic technologies programs number (project no. 12-wat 2453-02) in the kingdom of saudi arabia. references al-faifi, h.j.a. (2005): evaluation of groundwater resources in wajid aquifer in wadidawasir area southern saudi arabia, using computer simulation.– m.sc. thesis, king saud university, riyadh. american public health association (apha) (1995): standard methods for the examination of water and wastewater, 19th edn. apha, washington dc, usass. batayneh, a. & zumlot, t. (2012): multivariate statistical approach to geochemical methods in water quality factor identification; application to the shallow aquifer system of the yarmouk basin of north jordan.– res. j. environ. earth. sci., 4/7, 756–768. cloutier, v., lefebvre, r., therrien, r. & savard, m. (2008): multivariate statistical analysis of geochemical data as indicative of the hydrogeochemical evolution of groundwater in a sedimentary rock aquifer system.– j. hydrol., 353, 294–313. dabbagh, m.e. (1981)(ed.):environmental interpretation and tectonic significance of thewajid sandstone, saudi arabia.– m.sc. of science, university of north carolina, u.s.a., 84 p. dabbagh, m.e. & rogers, j.j.w. (1983): depositional environments and tectonic significance of the wajid sandstone of southern saudi arabia.– journal of african earth sciences, 1/1, 47–57. gulf countries committee standardization organization., (gso) gso5/ (2008): unbottled drinking water. hakan, arslan (2013): application of multivariate statistical techniques in the assessment of groundwater quality in seawater intrusion area in bafra plain, turkey.– environ monitoring and assessment, 185, 2439–2452. helsel, d.r. (1990): less than obvious: statistical treatment of data below the detection limit.– env. sci and tech., 24, 1766–1774. helsel, d.r. & hirsch, r.m. (1992): studies in environmental science 49. statistical methods in water resources, elsevier, new york. italconsult (1969): water and agricultural development studies for area iv, eastern province, saudi arabian”.– unpublished report to the ministry of agriculture and water, riyadh, kingdom of saudi arabia. kellogg, k.s., janjou, d., minoux, l. & fourniguet, j. (1986): explanatory notes to the geologic map of the wadi tathlith quadrangle, sheet 20 g, kingdom of saudi arabia. ministry of petroleum and mineral resources, deputy ministry for mineral resources, 27 p. manku, g.s., rajagopalan, s. & lindsay, b.g. (1999): random sampling techniques for space efficient online computation of order statistics of large datasets.– in: proceedings of the acm sigmod international conference on management of data, 251–262. moshrif, m.a. (1989): fluvial environment of the southern part of wajid sandstone (cambrian – ordovician) deduced by textural analysis”.– iraqi journal of science, 30/1, 47–71. moshrif, m.a. & el-hiti, a. (1989): lithofacies and petrography of wajid sandstone (cambrian-ordovician) saudi arabia.– journal of african earth sciences, 9/3–4, 401–412. newcomb, w.d. & rimstidt, j.d. (2002): trace element distribution in us groundwaters: a probabilistic assessment using public domain data.– appl. geochem., 17, 49–57. reghunath, r., murthy, s.t.r. & raghavan, b.r. (2002): the utility of multivariate statistical techniques in hydrogeo-chemical studies: an example from karnataka, india.– water research, 36, 2437–2442. sall, j. & lehman, a.(1996): a guide to statistic and data analysis using jmp and jmp in software sas institute inc. duxbury press. sinclair, a.j. (1974): selection of threshold values in geochemical data using probability graphs.– j. geochem. explor., 3/2, 129–149. stump, t.e. & van der eem, j.g. (1994): the stratigraphy, depositional environments and periods of deformation of the wajid outcrop belt, southwestern saudi arabia”.– journal of african earth sciences, 21/3, 421–441. u.s. environmental protection agency. (2002): storet, u.s. environmental protection agency. office of water. available from: <http://www.epa.gov/storet/> (last accessed 08.12.04). zhang, c.s., deirdre, f., david, m., eamonn, g. & owen, t.c. (2008): statistical analysis of geochemical variables in soils of ireland.– geoderma, 146, 378–390. manuscript received september 10, 2013 revised manuscript accepted may 28, 2014 available online october 31, 2014 geol. croat. zagreb 1996 prof essional paper geolosko-ekonomski esej: " ... koordinirani napori svih zainteresiranih subjekata svjesnih sebe, svojih interesa, svojih mogucnosti i svoje odgovornosti..." (pletikapic, 1988) jozer simon klju cnc rij cci: opus el l zi vka plclikapica, promicanjc i11ctocio log ije, geolosko-ckonomsko vrcdnov3nj c zal iha, status istrazivanja !lafte i pi ina. sazclak .. buduci .~c pojam i ~ l razivanje ii ll zem s rn is lu odn os i na prv ll raw cikl usa priprcrnc tzv . o tkrivcn ih za liha , odnosno prognoz iranjc !t.v. llco(krivcni h zali ha, sa,stavni jc dio trazcnja ]dista kojc obuh vaca faze rckognosciranja i prospckcij c, a zavrsava sc , ino rn o lkriv.ltij a, cla kako, $,1111 0 11;\ prostoru novootkriv enog lez i; la .. . ncs urnnjiva jc po l reba stalnog lillaprcdivanja vl as tite metocio log ij c prngllo ;dranja prosto rnog razmjcs l<lja i vrijednosti neotkrivcnih zaliha nane i plina .. i s tra~. i vanjc l ezi.~ta ugljikovodika moie z(\uzet i i <l finn i!"a ti svoj polo~aj i lil ogll ii sfe ri mate rijal nc pro izvodnje til uvjet cia istrazivaci .wjcsno, sam! ogran icc svojc pravo na pogrcsku plltcm o tkri va nja i pos tivanja pravi la za r'lcionalno vodenje istrazivanj a . p rije svcga, svjcsnim uk lanj anjcrn svi h vcl ova tiljn i oko svog pos la te stvaranjclll livjcta i'a objcktiv ll ll ckono mskll va lo rizacij ll svoji h pro izvoda istrazcnih zaliha mi ncralnih sirovi na ... " (pletika pic. 1988). odabrani sll saz.cti od lomci iz pro mi s ljcnih djela dr. zivk'l plctikapica (1928 1990), uglcd noga znan"tvenika i li v<l 7..enog pregao­ ca hrvat),]..c n,lfmc gcologijc, b il i svoj edobno, jos vise dan-(];m:ls vrlo ak lual ni prilozi prolllicanj u ),uvremenih gco losko-ckonollls]..ih ]..on­ ccpcija 1i slis tav nolll prisllip li upravlj anj u proce)'om j),traiivanja iczis la nafte i pl ina u nas. upravo. to je lljed no okosn iea i po taznica ovog itlaganja . * :;: * (pletika pic, 1964) " .. . islrazivanjc lciisla nalk i pi ina, unaloc ve li kom riziku koj i u scbi nos i, nije ha ­ zard nego posao s od rede nim rudarsko-gospodarskilll c il jcm . is traz ivac i moraju biti sposobn i da una prijed procje nj uj u ri z ik svakog svog pothvat a i cia ukl one iz svog pos la o ne u koj im a j e proc ije nje ni ri z ik vec i oel elozvoljcnog . to je danas moguce os tvariti clos ljcdnom pri mje no m s uvreme nih mclodo loskih konce pc ij a istrazivanja u lehn oloskom proccsu, koji ce voeli li orga­ ni zac ij a objektivi s ti ckog tipa. ulvrdivanj c rczullata voj nov iceva 24 . i iri 0000 zagreb, croatia. proceedings key wo rds: opus of dr. z ivko p le ti kap ic, improve­ ment of methodology, geo logic-econom ical evalua­ lion of reserves, statlls of oil and gas ex plorat ions. abstract .. since the very concept o f exploration is, in the st rict se nse, related to the fir st ph ase of the cycl e o f pre pa rat io n of d iscove red reserves, in o ther words the prognos is o f undiscovered reserves, it is an int egral pan of prospec ting for th e hyd rocarbon poo ls w hich incor­ porales th e phase of recognition and the phase of pros pecti on, endi ng wit h the act of d iscove ry, nulll ra lly, only in the area o f a newly di s­ cove red poo l. . . the need for consta nt im pro vem ellt of o nc ' s own me thodology of prognosis of d istributi on and va lue of und isco vered o il and gas reserves is unques ti ona bl e ... the exp lo rat ion for hyd roca r­ bon deposit s can take and a ffir m it 's posit ion and role in the sphe re of m a terial produc ti on only prov idi ng th e fo ll ow ing cond it ion is met : that the ex plore rs themselves, consciollsly li mit their ri ght to make m is takcs by fi nding o ut and respecting the ru les of rational cxplo­ ration proced ure. above all , th is is 10 be done by coil\cious removal o f all of the vei ls of m ist that arc d rawn over one's work and by mak ­ ing co nd itions for the objective econo mic va lua ti o n of one's own products the a lready di scovered reserves of m inera l deposi ts .. . .. (pletikapic.1988). the chosen conc ise passages arc taken fro m the clelibcr;.l1e works or dr. zivko p1cti kapic ( 19281990). di st ing ui shed scie nt ist an d esteemed professional of croatian petro leulll geo logy . they presen ted then, and are presenting even m ore this very mo ment, exce ptio nally valuable c011l riblltions to the improve ment o f mode rn geolog ic-eco­ nom ica l concepts within the system at ic approach toward s the manag­ ing or th e proccss of oi l and gas exp lorati on in c roatia. thi s is th e vc ry ske leton and a lso the starti ng poi nt 0 1" this presentati on. rada takve organizac ijc putci1l ocje nc ckol1olll ske vri ­ jednosli njcnih proi zvoda novootkrivcni h incl uslrijskih rczcrvi na ft e i plina moze ubrzo rezulli rati stvaranjem poz iti vnog mc ha ni zma slilllulac ije na povccanjc pro­ dukt ivnosti , ekonolllicnosti i re ntabilnos ti pos lova nja (plet1kap1c. 197 1) " ... poznalo jc cia sli 1iiagallja u trazenje no vih naftnih i plins ki h lez is ta o bavije na vejoj11 neizvjesnosti povrata ulozcnih srccls tava, a li is to tako cia od ti spjesnosli njihova otk ri vanj a za vi si kollli ­ nuitct rcproclukcijskog procesa naftnc privreclc. n e iz­ vjcsnost u kojoj se gubi iii ncocckivano dobiva slvorila je kod investi tora asoc ijac iju istovj e lj10s ti irazenja lezisla s igrom na srcc ti. olud naz iv ie kriti cne fa ze 306 istrazivanja istrazivacka igra, a iu se vjerojatno nalazc i korijeni hazarderskog ponasanja nekih njenih ucesni­ ka. izazov protiv neizvjesnosti ovog posla prihvatili su geolozi i geofizicari pripremajllci tzv. perspektivne lokalitcte za icstiranjc busotinama, kor isteei sc svc sl07.enljolll tchnikom i metodama rada, clji je zajcdnicki cilj livijek lokalizacija zamki za ugljikovodikc na poclrucjima gdjc jc izvjesno postojanje prirodnih rczcrvoara . moguenosl uvodenja ekonolllskih kriterija u vrcdnovanjc projckta irazcnja lezista nanc i plina autor vidi ii lllatcmatskilll illodclillla islrazivacke igre koji povczuju ovisnost vjcrojatnosti otkrivanja ad broja pokusaja i koeficijenla unosnosli odnosno nelo sadasnje vrijcdnosli renle koja bi se u slucaju otkrivanja lezis la illogla postiei. funkcije slozenc iz ovih varijabli pokazuju kakyi su izgledi cia se projcktirani pothvat zavrsi uspjesno i koje su krajnjc graniee raeiollalne upomosli istrazivaca i inveslilora u igri pri clefiniranim prirodnim i ekonomskim uvjelima ... " (pletlkapic & boskov-stajner, 1973) "", borba za rast reproduktivne sposobnosti proeesa ist razi­ vanja povecava njegovu dinamicnost. buduei cia za dovrsenje punog eiklusa istrazivackog dijela pripreme zaliha cfaze: selekcija prostora za istrazivanjc, sclekcija loka lit c ta, priprema prospekla, olkrivanje iczista, isl razivanjc lez ista) moze biti potrebno 510 godina, u dinamickom procesu neminovno je otpocinjanje nov ih prijc dovrscnja ranijc zapocetih c iklush. tako sc u pro­ eesu pojavljuje potreba neprestanog obnavljanja aklivno st i u svilll fazama sa ci lj clll priprelllanja aktu­ a lne osnove za donosenje oelluka ii narednll fazl! napre­ cllljucih c iklusa. za kontrolu i upravljanje takvjm elina­ lllickilll proccsom u kojem se pojavljllju problemi usklaclivanja faza, najveei znacaj imaju azurnc bilance vrijcdnost i zaliha svih kategorija i elinamicki planovi koji obuhvacaju eitav proces ... ... sloga, primjen u tehnike mreznog planiranja u is trazivanju lczisla nafte i plina treba razvijati, jer je ona u sta nju da dopr inosi llnapredivanju organizacije racia, ubrzavanju procesa i slllanjivanju troskova istrazi­ vanja. bez nje ec u uvjetima sve yeee pocljele rada biti sve leze odrediti illjesto, ulogll, odgovornost i meduovisnost suciionika ii istrazivanju te na taj nacin os igurati integritet procesa i sklaclno oslvarivanje nje­ govi h ciljcva ... " (pletlkapic & hadziv eljkovic, 1975) "", stralcgija svladava nja opasnosti od trajnog gubljenja srecls tava u c iklusu reprodukcijskog proeesa indust ri ­ jskc proizvocinje lllineralnih sirovina svodi se na dosljcdnu primjenu principa postupnosli i principa obi­ ranja. princip postupnosti nalaze oprcznost pri ulazenju u novi c iklus i nepreslano prcispitivanje izg leda za ostvarivanje poslov nog uspjeha u sto j c llloguce sirim okvirima ist raznog prostora i na slo je moguee veeem broju objckata. prineip obiranja nalaze cia sc nakon svakog prcispilivanja selektiraju objekti, obuslavi ulageologia croalica i19/2 ganje u visu fazu priprcme na onima koji ne obecavaju moguenost rentabilne proi zvodnje, ana ostalima pove­ eava intenzitet radova i gus loeu ulaganja redoslijeciom ustanovljeni m na leme lju kom pleksnih kritcrija gco ­ losko-ekonomske ocjenc vrijcdnosti njihovih zaliha ... .. stoga je sin teza geolosko-ekonomskih informaci­ ja, poznala pod nazivom klasifikacija i kalegorizacija za liha iii gco losko-ekonomska ocjcna vrijednosli zali­ ha, poslala u suv remcnoj teoriji vodenja reproclukci ­ jskog procesa industrijske proizvodnje mineralnih sirov ina glavnilll kri tcrijem pri donosenju oelluka 0 ula­ ganju sredstava . bez pomoei klasifikac ij e i katego­ rizacij e zaliha invest itori ne 1l1ogu s igurno uklonili opasnost trajnog gubljenja ulozenih sredstava u novi e iklu s, koj a se pojavljuj e zbog nepovratnosti procesa unutar eiklusa . opasnost trajnog g ublj cnja ulozcnih sreclslava je to veea sto je veea neizvjesnosl rezu ltata ulaganja i sto su veea sreclstya potrcbna za pokrivanjc in vcst icijske faze c iklusa . (pletikapic, 1975)" " isl razivanje kao proces po bilnim karakteristikama ne razlikuje se ocl clrugih repro­ dukeij skih procesa, a te karakl erisl ike su neizvjesnosl, nepovralnost i ciklicnost ... ... da bi se pak izbjegli uzaludni napori, polrebno je pos ti va t i dva osnovna pravila: pravilo postupnost i u trazenju optima[nog puta i pravilo usklaclenosli sv ih akcija usmjcren ih odabranom cilju. prvo pravilo u pro­ cesu ist razivanj a lezisla minerajnih sirovina u clobroj illjcri jc vce razradeno hoz ideje 0 kategorizaciji zaliha mineralnih s irovina i postupnosti prevodenja niz ih u vise ka legorij e . pravilo optimalne usklad enosti sv ih akcija usmjerenih k c ilju za proces istraziyanja lezista mincra lnih sirov in a je znalno slozen ij e i zbog toga slabije razradeno, al i su neki njcgov i clementi vee dobro pozna ii. tako se, na primjer, cini da jc dovoljno j asno cia u slozenom procesu koji u scb i saclrzava vise naprecillj ueih ciklusa, prioritcl u naporillla za njihovo nastavljanjc imaju ciklusi najblizi konacnom cilju . u proizvodnim proccs im a glavni inst rum enti kontrole jesu bilanee, a regulacije projckliranje, pro­ gramiranje i planiranje. sislem kontrole i reglllacije ist razivanja lezista mineralnih sirov ina pociva na vred­ novanju svi h kategorija, koje sc obicno nazivaju geo­ losko-ekonomska ocjena. prije svega, kao glavni krile­ rij ocjene usvojcn je univerzalni kriterij za vrednovanjc svakog poslovnog pothvata: neto-sadasnja vrijednosl i interna kamat na stopa. zbog visokog rizika, ima­ nentnog istrazivanju, u gco]osko-ekonoms ku ocjenu ukljuccnaje takoder njegova anal iza i procjcna ... ... medutim, pojedinac se tcs:ko opire utisku cia 1i nasoj islrazivackoj praksi te teoretske koncepcije jedva postoje i da su velikoj vecini ijudi koji svojim radom slldje luju u istrazivanjll gotovo ncpoznate . mnog i su frustrirani zbog nellspjeha svojih nastojanja da ih razli­ miju. njihova nemoe je posljedica slabosti u obrazo­ vanju , slaboj i neorganiziranoj pollloei clrustva cia se prazn lllc pop line, ali p rycns tveno to jc poslj cclica indifercntnosti ... " simon: cicolosko-ckonohlski esej: ·· ... koordin ir:l1l i napori svih zainlcrcsiranih subjebul..:· 307 l z izlozcnog proi st iec da isl razivanjc moze zauzeti i afirmirati svojc mjesto u s f"eri malerijalne proizvodnje samo ako osnovni sllbjekti i nosioei repro­ dukeije uspiju da premostc jaz koji postoji izmedu prakse i teorctskih lllogucnosti za ekonomsku valo­ rizaciju svojih proizvoda ist razenih za l iha mincralne sirovine ... " (pletikapic , 1980b) a ... razvoj svc s iozenije organ izacije otkrivanja !czisla mineralnih sirov ina ne teee g latko, bez probl ema i proturj ee nosti, narrativ. jedan od kl jucnih jc svakako problem dje lo tvornost i inlcgriran ih snaga i srcdstava, problem njihova usmje­ ravanja i razvi.ianja ii praveu koji cc ih osposobljavati za zajcdnicko, skladno djetovanjc, jer u dosaelasnjem razvoju jc bilo i dosta lutanja i zabluela. svijcst 0 znatno vccoj slozcnost i pitanja djelotvornosti vrlo slozenc organizacije otkrivanja le7. isla mincraln ih sirovina, kao i odredena nastojanja da sc ona rij cse, takoder jc odavno prisutna . sva ta pitanja i nastojanja obicno su, iako 0 lome nije bilo opee suglasn osti , svrstavana u illelodoloska. no, nerijetko sll se i tehnike i tehnologijc prillljenjivane u polhvatima i procesima otkrivanja illincralnih sirov ina nazivalc mctodama . to i ne eudi ako llzmelllo u obzir s kakvim stavovima i ambicijama su one llvoelene u praksu . pojam mctodologije otkrivanja i istra7.ivanj a lezisla lllinerainih s irovina sve do nasih dana nije raz­ jasnjcn ni po sadrzaju, ni po rasponu tretiranih proble­ ma. no iz onog slo sll brojni au tori pisal i, moglo bi sc zakljueiti da jc vccina poel mctoelologijom pod razumije­ vala trct iranje svih pitanja u vezi s uprav ljanjcm pot­ hvatima i proeesima. taj tretman je obuhvaeao otkri ­ vanjc sv ih rclevantnih ein ilaca koji su oel utj ccaja na ishodc pothvata i procesa, proucavanje njihovc meduza­ visnosti te ustanov ljavanja pravila, principa, shema i modcla po kojima ee sc ostvarivati njihova optimalna intcrakcija u praveu postizanja zcljcnih rczultata . ... prvi znacajn i eloprinos operacionih istrazivanja u otkrivanju lei-ista mineral nih sirovina, bi lo je razv ijanje svijcsti 0 stohastickom karakterll polhvata i procesa i 0 potrcbi da se 0 tom karakteru vodi racuna pri likom donosenja svake operalivne odluke. istina jc da su istrazivaci lczista mineralnih sirovina oduvijek znali i ccsio glasno isticali prisutnost vclikog rizika u svojim pothvatima, ali sll sve elo nasih dana malo urad il i na njcgovoj kvanlifikaeiji, pa jc on cesto, prilikom donosenja konkretnih odluka potpuno ignoriran. naj­ vaznija novost, ii odnosll na konccpc ije na kojima sc zasniva procjena vrijcdnosti relocrv i mincralnih siro ­ vina, jcstc saznanjc snazno polaknuto opcracionim istrazivanjima, da ona po svom karakteru ne moze bit i eleterminislicka, vee mora biti probabilisticka. za saglc­ davanje svrsishodnosti ulaganja u nared nu fazu priprellle bitan je oelnos izmeclu occkivan ih dob itaka, prcdstavljcnim sla ti stickim prosjekom neta sadasnjih vrijcelnosti mineralnc supstancc, i occkivanih gubitaka, predstavljcnih statistickim prosjekom neto sadasnje vri­ jednosti troskova narcd ne faze pripreme, a sve u ovisnosti od vjerojatnosti dobitka, odnosno gubi tka. taj odnos poznat jc pod nazivom ocekivanc (monetarnc) vrijcdnosti pothvata. konccpt i postupak odrcdivanja ocekivanc vrijcdnosti nlleli objektivne malematicke okvirc ispitivanja stralegijc podje1c rizika kroz zaje­ dnicka ulaganja u svaki konkretni pothval. dalcko vise mogucnost i pruza, ali i puno novih problema olvara, koncept tzv. preferencijalne iii utili tarne v rijednosti, 1i kojem je uk lj uccno uvazavanje subjcktivnih stavova ulagaca prema velicinama mogucih gubitaka i dobitaka, kao i prcma vclici ni rizika ... ... idealna shema priprcme rezervi mineralnc sup­ stance za ckstrakciju dozvoljava nam da razabcrcmo mogucnosti koje nam ocekivana vrijednost pruza ii regulaciji cjelokupnog procesa pripremc. sasvim jc jas­ no da cc svako ncopravdano produzavanje pripreme, obzirolll na eksponcncijalno povecanje konccntracije ulaganja, is to tako kao i ncopravdano prekidanjc pripreme , uz priznanje gubitka ulaganja i napustanje lllogucnosli za ostvarenje dobitka, razomo eljclovati na akumu laciju i smanji vanjc reproduklivne sposobnosti procesa. to su realni izvori opasnosti za nekontrolirane spontanc procese, da ee llnatoc eventua lno vclikim pocetn im lispjesima, zavrsit i katastrofalno. altcrnativa koja pobuduje naciu, a nazire se iz naprijeel opisanih teorctskih 1ll0gucnos ti, jeste inteligentna kontrolirana regulacija procesa. tako ni ona nc moze el iminirati svc gubilke i obeeati vjecnost reproelukcijskom proccsu, ona ga mozc spasiti od katastrofalnih gubitaka akumll­ lacije i ornogucili njegovim nosiocima izbor buducnosti osloboelen pritisaka ... razmjena infonnacija 0 naprelku teoretskc osnovc upravljanja reprodukcijski m proccsima, kao i napretku ostvarenom u konkrelnim pokusajima njenog koristcnja u svakodncvnoj praksi odillcivanja, od sirokog je strucnog, naucllog i drustvcnog interesa ... " (pletikapic, 1987b)" .. uvodenjclll monte car­ lo simulacije u poslupak izracunavanja, formalno je neto saelasnja vrijeel nost dobiti ostvarive ekstrakcijolll zaliha degradirana, oel infofmacija na razinu podataka. islovrcmcno je poecla evolucija statusa ideje ii zivim, reprodukcij skim procesi ma proizvodnje. raspravom se sugcrira mogucnost ielentifikacijc bar triju statusnih g radacija kroz koje ideje, oel kuriozilcta koji privlaci pojcelince, prerasta u izazov i, konacno, 1i rulinu ncophodnu svakoj organizaciji koja hoee da ima svoj, suvremcno koncipiran sis tem infonnaeija, kol11unika~ cija, oelillcivanja i planiranja pripremc zaliha za ekstra­ kciju. manifcstacijc tc evol ucijc, iako su uocljive, mno­ gim a jos nisu jasnc. otud nedoumice upravljaca, u vre­ mcnu u kojem je jos moguc izbor izmedu prihvacanja idejc i njcna da ljnjcga ignoriranja . (pletikapic, 1988) " ... proglloziranje prostornog razmjestaja i vrijcdnosli tzv. ncotkrivcllih zaliha sasta­ vni je dio globalnc djelatllosti istraiivallja lezlsta naftc i plina. sinonimom prognoziranja u sadrzajnom sm islu bila bi k/as!fikacua naznaecnih zaliha. zbog upotrebe 308 procjena ishoda alt. nizova rizie. pothvata periodieno bilanciranje promjena vrijednosti svih zaliha analize svrsishodnosti pribavljanja dodatn ih, nepotpuno pouzdanih podataka geologia croalica 49n klasificiranje zaliha svih procesom obuhvacenih lez ista, nakon svake promjene cinilaca od utjecaja na njihovu vrijednost ----------------------r------------------mcs nsv zaliha analize rizika si. i skica polozaja monte carlo siltl­ lllacije neto sadasnjih vrijcdnosti za liha nafte iii plina ii stvaranju inrormacijskih podloga za sve operativne, takticke i strateske odlllke u sklopu upravljanja pri ­ prcmom zaliha za ekstrakciju. prikupljanje, sistematiziranje, obrada i verificiranje ulaznih podataka za izvodenje mcs nsv zal iha i analize rizika pojma "progllozlle" za zalihc d (d , i d2) kategorije tre­ ba reci cia pojam "neolkrivene zalihe') pokriva dijapa­ zon od d j do c2 kalegorije. buduci se pojam "istraii­ vanje" 1i uzem smislu odnosi samo na prvll fazu ciklusa pripreme tzv. olkrivcnih zaliha, prccizllijc bi bilo reci da je prognoziranje naznaeenih zaliha sastavlli dio 'raiellja lezista koje obuhvaca faze rckognoscirallja i prospckcijc, a zavrsava sc ci llom otkrivanja, dakako, same na prostorll novootkrivenog lczista ... ... obicno sc pojcdnostavnjeno smatra da su prog­ noze, tj. illformacije sto ih ovdjc razmatrano prognozi­ ranjc daje , neophodne samo lflagacima kao pod loge za donosenj e odluka. bit ce ipak, da su one potrebne i nekim drugim sllbjektima, odnosno, da se pojam ula­ gaga mora znatno prosiriti na sve one pojedince i/i1i organizacijc kojc svoj ops tanak bar djelomicno zasniva­ ju na unoveavanju nckog odfaktora proizvodnje inkor­ poriranog u proces njegove (i ne samo njcgove) trans­ formacij e u tzv. novu vrijednosl. rijec je naravno 0 procesima reprodukcijc u tzv. ckstraktivnoj industriji (ekstrakciji mineralnih sirovina), preciznijc u procesima istrazivanja i proizvodnje nane i pi ina ... da ii je ipak moguce dati i'ormlilaciju smisla i sv rhe prognoziranja koja bi bila za sve prihvalljiiva? mozda, ako bismo rek li da je smisao i svrha prognozi ­ ranja da pruzi infonnacijsku podlogu za (1) djelotvorni ­ ju transformaciju svih proizvodnih faktora u novu vri­ jednosl i za (2) djelotvornijll zastitu legitimnih interesa svakog vlasnika proizvodnih faktora ukljucenih u trans­ formaciju ... ... svaka metodologija, kao posebno dobro onih koji su uspjeli opcraciona lizirati izvjesne, opee dost upne, znanstvcnc principe i alate 1i svojoj svakodnevnoj prak­ si, gubi konkurentnost ako sc stalno ne linapreduje lisvajanjem novih dostignuca relevantnih grana znanosti i tchnologijc. prisutne su stanovite potrebe, mogucnosti i teskoce vezane s linapredivanjcm viaslile metodo lo­ gije prognozi ranja prostornog razmjestaja neolkrivcnih lezisla i vrijcdnosti njihovih zaliha ... skica dosadasnjeg razvoja metodologije ovog prognoziranja kod nas, posebno odnosa legislative pre­ ma tom razvoju, daje mjesta pretpostavci da je glavni uzrok poteskoea prikriveni sukob tzv. grupni h interesa koji bi se mozda lakse prevladao kada bi se shvati li i prihvatili svi valjani argumenti sudionika u procesu istrazivanja iczista nafte i pi ina . ... unatoc tome sto postoje izvjesne mogucnosli, onc su rasprsene i oeito nisu dovoljno iskoristene. zbog toga su potrebni dodatni, sinkroni zirani i koordinirani napori svih za intercsiranih subjekata svjcsn ih sebe, svo­ jih moguenosti i svoje odgovornosti ... " (pletikaptc, 1991) " .. t he primary intention of the pbox (pannonian basin oil exploration) project , being now in the phase of initiation, is the accomplish­ ment of a rather complex methodological experiment. 1t is conceived to be aimcd towards defining spatial posi­ tion and the emv (expected monetary values) of any discovercd or undiscovered oil or gas pool, enclosed in structurally or stratigraphically controled trap, what is held to be a proper parametcr for the evaluation of the simon: gcolosko·ekonomski cscj: ", .. koordinir;lt1i nnrori svih zaintcrcsiranih subjekala ... " 30t) market value of the remaining oil and gas reserves, as well as for their classification ... ... from the organizational stand-point it seems con­ venient if the pbox project would be divided into three stages, each one choosing a proper part of basin as a playground where could be exercised a treatment of: (i) a single structural (or stratigraph ic) horizon (unit); (2) multiple structural (or stratigraphic) horizons (regional oil and gas reservoirs) and (3) a transfer of experience in risk quantifications [rom the training to the largel area. each of the stages cou ld be further divided into phases: (1) initiation; (2) conceptual ization; (3) defini­ tion; (4) exccution and (5) esscntialization . perhaps, it might be concluded that ihe here announccd preliminary concept or the pbox project seems promising as well as challenging for all partici­ pants in the oil and gas exploration within the pannon­ ian basin. since thcre is no evidence ihat similar chal­ lenges al\vays provoke proper actions, the best option is to keep trying to live with hope. but, if any act ion on this way happens, it is reasonable to expect some kind or cooperation among the slated participants, as well as ihe synchronization of their effort s." to su odabrani, kronoloskim redom svrstan i odlom­ c i iz objavljcnih djela dr. zivka plelikapica (19281990) jcdnog ad najuglcdnijih strucnjaka i znanstveni­ ka, pravog profcsionaica suvrcmene povijesti hrvatske naftnc gcojogije. njegovo trideselpetogodisnje stvarajastvo (kra­ njec, 1991) nabijeno je znacenjima i dllbokim misli­ ma, iznad svega, izazovima i pilanjima 0 unapredivanju suv rcmenih idcjnih, mctodoloskih i strateskih obiljezja nase naflnogeoloske prakse. glavna mu jc obuzctost i djelatnost geolosko-ekonomska problematika uprav­ ljanja procesom istrazivanja lezista ugljikovodika oel "ekollol'llike isfraiivallja lefisfa liajfe i plil/a", tiskane 1964. god. (pletikapic, 1964) do "pannonian basin oil exploration project"-a, posmrtno objavljenog rada (pi_etikapic, j99j). misljcnja sam, cia sc cjclokupni gcolosko-ekonom­ ski opus z ivka pletikapica , sazeto i usmjereno prcd­ slavlj en u uvodniku/raspravi rcrcrata, skladno i polrc­ bito uklapa ii aktualnu tclllatiku ovog znanstvcnog sku­ pa. stovise, oillogucava dolllis ljanje tclllcljniil postavki za daljnje razvijanje/predlaganje idcjnc osnovc za upra­ vljallje reprodllkcijskil7l procesofll priprcmallja zaliha za proizvodnju, tj. sllvrcmcni s/lsfavl/i prisfup isfrazi­ i'anjll leiisra nalre ; piing 11 nas: (i) opec gospodarsko-straleske znacajke mineralnih sirovina, posebno ugljikovodika i reprodukcijskih proccsa u nasoj naftoplinskoj privrcdi. (2) temcijllc odredbe slalusa, mjesta i uloge istraziva­ nja nane i pjina, njcgova ustrojstva (sudionici i nji ­ hovi illeclusobni odnosi) i srcdstva upravljanja (planovi, programi, projekti). (3) uvazavallje prirodnih progresivnih faza u ciklusu istrazivanja i razrade iczista, ij. postupnog pove­ cavanja priprcmljcnosti njihovih zaliha i katcgorija (faze idcalnog c iklu sa: izvidanje d 2 , rekognoscira­ nje d j , prospektiranje c2, otkrivanje e l , ispiti­ vanje 13, razrada a). (4) kompleks sintczc infonnacija u upravljanju rezcr­ voarillla naftoi plinonosnicima (segmenti: sinteza strati grafsko-talozni h, tektonsko-strukturnih, rczer­ voarsko-iczisn ih, rudarsko-ekonomskih , ... informa­ cija), tj. polazna informacijska podjoga projckata, programa i planova za istrazi vacke radove prila­ godenc pojedinim fazama ciklusa. (5) geolosko-ekonoillska ocjena vrijednosti zaliha, tj. inform.acijska podloga opravdanosti ulaganja u ost­ varenje projekata, programa i planova: (a) koncept vrijeelnosli lezista (resurs i i zalihe, kriteriji njihove klasifikacije), (b) koncepl neto sadasnjih vrijednosli za liha (analize vremcnskih vrijednosti novca, mcs nsv zaliha), (c) koncept ocekivanih monelarnih vri­ jednosti (anali ze rizika i odluka) i (d) koncepl pre[c­ rcncijalnih vrijednosti (anajize polencijala ulagaca). (6) 1zbor i ozivotvorenje oplimalnih stratdkih, laktickih i opcrativnih odluka i ulaganja. (7) stalna kontrola svih eljelatnosti u sklopu upravljanja procesom istrazivanja jez ista naftc i plina. je ii moguce (a prijeko jc potrebito!) zauzcti stay 0 sadas njici i sta tusu upravljanja procesom islrazivanja u novim trzisnogospodarskim okolnostima nase privrcdc? zacijelo da, ako bismo pokrenu ji svcobuhvatnu analizu njegova ustroja i polozaja, kao npr. unutar izv. "centara troskova" a naspram lzv. " profil nim ccntrima" u shemi organizacijske makro-struklure ina ci.d. (osnove orga­ nizacije ina-industrije nafte d.d., zagreb vjcsnik ina, zagreb, 10.06.1995., sir. 6-7). o takvoj i slicnoj pojavnosti, dakako , 0 njczillom svrhov itom rasclanjivanju i tumacenju kao uvaza­ vajueim porllkama svim sudionicima proccsa istrazi­ vanja, vee je prijc 20-ak goclina progovorio zivko plelikapic (pletika pic , 1974), kad " ... je u svoill rcfcratu pod naslovom: uljcfi pod kojil1la istrazival/je maze biti prizl/aro .\ferorn matcrijallle proizvodnje ukazao na veliki jaz izmedu tcorctski h moguenosti za upravljanjc i kontrolu procesolll istrazivanja s jedne strane i stanja u nasoj praksi s druge strane. zalozio sc da se nasuprot troskovima istrazivanja, koji imaju svojc stall10 mjcslo u planovima i bilallcama istrazivackih organizacija te vuku istrazivanje u sfcru potrosnje i naelgradnje, uvedu u njihove planove i bilance i pokaza­ telji vrijeclnosti nedovrscne proizvodnjc sadrzane u zali­ ham a mincralnih sirovina najviscg slupnja priprc­ mljenosti (a+b katcgorija). time bi se dobili indikatori opravdanosti i 1ispjcsnosti ulaganja 11 istrazivanjc, kao sferc materijalne proizvodn je." na kraj 11 , ovoi11 s1l strucnom eseju prikljuccne onc reference promisljenih radova zivka pletikapica koji su bili svojedobno, a jos vise dan-dallas izuzctno vrijedni i 310 akt ll alni doprin os i prol11icanju suvrcmcnih geo!osko­ ckonom skih konccpcija ll nasoj gco logiji, osobilo u njcz inol11 nartno-gcoloskoi11 ograllkll. literatura kr an jec, y. ( 1991): 1n memoriam dr. zivko pletikapic (9.9. 1928.12.1 1.1990.).geoloski vj es­ nik, 44, 34 1-344, zagreb. plet1kaptc, z. ( 1964 ): ekonomika istrai ivanja iczista nafte i plina.nafta , 15/1-2, 16-20, zagreb. pletik apic, z. (1971): ekonomsko vrednovanje pro­ jckata irazenja iczista naft e i pli n<l .naha, 22/4-5, 452-457, zagreb. pletj kap1c, z. ( 1974): savjetovanje 0 temi "lstrazi­ vanj e lezisla minera lnih sirovina kao sfera materi­ jalne proizvodnje·'.nana, 25/ jo, 552-555, zagreb. pletikapic, z. ( 1975): uvjeli pod koj ima so islra,i ­ va nje moze pri znali sferom matcrija lne proizvod­ nje.nana, 26/2. 99102, zagreb. pletikaptc, z. ( 1979) : yjcrojalnosni pri slup islrazi ­ vanjll i razracli jcz ista nahe i plina. rud. -geol. -naft­ ni l'akullel ( 19391979. god. ), zbo rni k radova "nova dosli gn1lca u geoznan ostima", 492-503, zagreb. pletikapic, z. (1980a): oceki vana vrijednosl kao krilerij klasirikacije nafte i plina.nafta , 3 1/8, 389398, zagreb. plettka pi c, z. ( 1980b): operacion a istrazivanja u olkri vanju [ez isla l11in eraln ih sirovi na.zbornik radova "savjclovanje 0 naucni m i tchni cko-ichno­ loskim islrazivanjill1 3 u geologij i, fll da rstvll i met­ al urgiji", knj. geologija, 109-1 18, savez inzenjera i lehnica ra mel. , geo !. i metal. strukc ju goslavije, bcograd. plettkapic, z. ( 1982) : primjcna anali ze svrsishod­ nosti pribav lj anja ncpolpullo pollzdanih poclataka iz gcofi zicke prosjjckcije.zbornik radova "savjetogeologia cromica 49/2 vanjc 0 rezultat ima dosaclasnjih geofizick ih ispiti ­ vanja", 241 -254 , savel, in zenjera i tchni ca ra rud. , geo!. i metal. struke jugoslavije, beograd. pl etlkapic , z. ( 1984) : modifikae ija newencl or­ povog postupka mon te ca rlo simu lacije neto sadasnj ih vrijednosti za liha nafte iii plina.nana, 35/12, 61 7-627, zagreb. pl et ikaptc, z. ( 1986) : ub rzanj e poslupka monic carl o s imu lac ij e ne to sadasnjih vrijedn osti za[ih a nane iii pli na. -nafta, 37/3, 13 1136, zagreb. pletikapic, z. (1987a): ubrzanje poslu pka mon ic carl o s imu lacije neto sadasnji h vrijcdnosli zali ha na rle iii plina (11).nana, 38/1 , 714, zagreb. pleti kapic, z. (1987b): slalu s monl e ca rl o si lllu­ lac ije neta sadasnjih vrijcdnosli zal iha naft e iii pli na. nal'la, 38/11 -12,6 17-621, zagreb. plet ikapic, z. ( 1987c) : i'rocjena ishod a konacnog slijeda rizicnih pothvata.zbornik radova "savjclo­ vanje 0 problemati ci istraz ivanj a res ursa geoter­ malnc energije", 42 1-433, savez inzc njera i teh nica ra rud. , gco l. i mctal. slruke jugos lavije, bengrad. pl et ik apic, z. (1 988) : kako unaprij ecl ili vl as tilu i11 ctodologiju prognoz iranja razmjestaja i vrijednosti neolkrivenih zaliha naft e iii plina?nafta, 39/1 [12, 673-68 1, zagreb. pletikapic, z. (1 991): pannonian bas in oil explo­ ration projec t. ed. sanu, 4. 379-388, beograd. pletika pic, z. & boskoy-stajner , z. ( 1973): pri mj ena tchnjke mrcz ll og planiranja 11 istrazivhnju leii, la nalie i plin".narla, 24/12, 654-660, zagreb. plet ikaptc, z. & hadziyeljkoyic, n. ( 1975): klasifi kacija i kategorizacija za liha u kollt roli rcpro­ dukcionog proeesa.na rta, 26/ 9, 456-459, zagreb. geol. c roat. 49/2 3 i 7 3221 4 figs. 1 zaoreb 1996 professional paper bright spot, avo inversion and synthetic on grubisno polje locality marija vidovic. miuenko rukavina, miros lav syrinek, jasmina buelic ane! mirjana milinovic-kolundzic proceedings key wo rd s: bright spot, a yo inversion and anal ysis, restric ted gradient stack, synthetic. abst ract bright spot analysis is generally used in exploration fo r hydroc<lr­ bons. especially in the sc:lrch fo r gas. however, many seismic am pli­ il1de anomal ies have noi been call sed by gas accumulat ions, but they arc re l:lled 10 lithological changes. a vo methods (amplitude vs. off­ se t rnclho(15) can be used to di stingu ish between ihe presence of gas and litholog ical cb;mgcs. the grubi silo polje fie ld has been defined and mapped by th ese methods. and a we ll. drilled afterward co nfirm ed th e res ults . after 'lcqui ring the we ll -logg ing data a synthetic was comp ut ed. the cor­ re lation of the sy nthetic with lhe reproccssed scism ic sect ions and the a vo data enabled the more precise vertical and hori zon tal defi nitiojl of ihe g'ls liccurtwlalion. th is method and resu lts contribute to lhe more rational exploration and developmenl ofa gas field. l introd uction bright spot analyses have been accepted in explo­ ration 1'0 1' hydrocarbons, especially in gas bearing areas for twenty years. a brigh l spot is related to gas accu­ illu lati ons in the beds , which significant ly a ffec t the se ismi c hmp litudes (re fl ec tion coefficients) and ca use ihl1p lil ude anomalies on seismic sections. howe ver, seism ic amplitude anomalies can also bc ge nerat cd by litholog ica l changes. to di sting ui sh between the presence of gas and litholog ica l changes a vo inve rs ion s (ampli tude vs . offset invers ion, i.e. amplitude re lated to the source-receiver distance), have been lised during the last ten years. t he a yo inversion and the bri ght spot methods have been liscd together to analyse the g rubisno po lje fi e ld. t he location and struc tural con tours o f this fi eld can be seen on fig. l. it is important to mention that the analys is of avo inversion does not imply the gas quan­ tity in a bed. afte r analyzing the drillin g re sults, and c rea ti on of a synthetic, the com plexity of th is gas accu­ mulation and the advantage of jo int methods became clearer. tna-nafwpjin, subiccva 29, hr10000 zagreb, croa tia. kljucn e r ij eci: bright spot, avo pre lvorba i analiza, ograniceni gradient stack, sintetski seizmogram. saietak anatiza "bright spot" opec je prihv<leenll 1i isl razivanj u uglj iko­ vodika, nmoci to pjina. med lhi m, mnoge seizmicke ampli ludne ano­ ma lijc ilisu uuokovane plinskim aku mu lacijama, ncgo su odraz li lo­ loskih pro mjena. za njihovo razlikov a nje s luze avo melode (ponasanje mnpti1uda glede lldaljenosti izvor-prijemnik). loka lilel grubi sno polje je lllv rden i okonlu ren ovim rnelodama, locirana jc busotina. koja je potvrdi la njihove rezllltate. nakoll izmjc­ rcnih karo taznih podataka izraden je s int etsk i scizmogram. korelac ije s int ctskog seizmog rama i seizmick ih profila (mog uce rcob radc i kore kc ij e se izmi cki h pod alaka i mjerenih brzi na) i "avo" ll1 etode pre tvorbi , omogucile su tocnije okof1turi v<lnjc lezisla u vertikalnom i hor izontaln0111 smis lu. sve 10 doprinos i racionajnij em istraziva nju i razradi lokalitcta. 2. interpretation t he grubisilo polj e fic ld, wh ich is a pa ri o f the bje lovar depresssio n, is situated in central croat ia, approx imately 120 km east of zagreb. in the region sur­ rounding this field the well s or· 1 (1940), or·2 and or-3 (1965) we re drilled on the basis of con tempo rary knowl edge by gravity surveys pe rformed before 1940 and be tween 1962-1965. t he survey dens it y was 1 point/km2. the data from the seismic survey performed by single fold and analogue equ ipment were a lso used. all three wells were barren . be tween 1975 and 198 1 a de ta il ed gravi ty survey was performed over a broader a rea with the dens ity of 10 point s/km2 which resulted ill eas ie r recogn it ion of the gravi metric maxim um. in 1990 more in tense regio­ na l seismic exploration of the bjelovar depression was perfo rmed , while the grub isno po lje fi e ld has been in tensively explored by seismic methods since 1992. based on the newly recorded regional line v. zden­ ci-2v -92 and the re-processed older lines which implied the ex istence of the bri g ht spot, the int erpre ta tion of gru bisno polje locality was perfo rmed. ]n 1994 a new well gr· 1 z was drilled. at -654 m depth the well encount e red the gas accum ul ation , with the gas/wate r contac t at -740 m. du ring 1994 and j995 add it ional 31 k geologi:l cro:llic:l 49n 1) ~ 2) 3) • 4) ___ · 1000 --5) 6) _ gnl ·140 m-7) .gr.1z 8) fig. i structural map of the ekmarker rs7 with the contoured main reservoir. legend: i) gas reservoir; 2) normal fault; 3) reverse fault: 4) isodepth lines; 5) sei smic lines: 6) estimated gas/water contact; 7) exploration well: r) analysed part of seismic section. seismic lines were shot, processed and interpreted. the result of this interpretation enabled more precise gas accumulation contouring (fig. 1). during the interpretation the following seismic dis­ plays were used: rap-stack (reflection amplitudc preservation -stack), phase and frequency attribut ions, avo inversion data (a yo angle trace analysis), gradi­ ent stack, and restricted gradient stack. as all the inter­ pretations cannot be presented in this paper, only the rap-stack section, avo angle trace analysis (fig. 2a), restricted gradient stack (fig. 2b), and correlat ion of well and seismic data (fig. 3) have been included. figure 2a represents the rap-stack section of the seismic profile grp-2y-9s. in the central part along the well gri z, three bright spots are visible in the interval between 600-674 mscc. the shallowest bright spot was caused by a gas pool, and a 100% relative gas concentration was registered during the well drilling (op overpressure) in the lower part of the equivalent of bregi sandstones of ek-marker rep silty sandstone (fig. 3). the deeper bright spot was caused by entering the klostar ivanic formation (ek -marker l1), which is lithologically represented by clast fragments and fossil karst. the deepest bright spot is related to the low velocity zone within the klostar tvanic formation (sonic log in the fig. 3), probably to the marker rv. these bright spots are accompanied by the presence of gas and the whole interval is overpressured l . the main gas accumulation is situated in the mosti member of the moslovacka gom f0n11ation (ek marker rs7), and in the basal tertiary (bt). the mosti member is represented by biocalcirudites bioealearenites, while the basal tertiary is represented by metamorphics. the top of the main reservoir is not represented on a rap­ stack section with a bright spot, because of the consid­ erably higher velocity of the carbonate matrix. due to the gas accumulation the reflection coefficients are weakened (dim spot). the posi tive amplitude is barely visible on the section. entering the main gas accumula­ tion, the overpressure is lost. i vuk:ldinovic, m. (1995): zavrsno geoiosko izvjesce za istraznu busotinu grubisno poljei zapad.unpublished report, ina-naftaplin library. vidovic. rukavina. syrinck rijclic & milinovic· kolundiic: bright spot. avo invcn;ion :mj syll1helic 011 .. 319 , ... iii a cop 85' b ., ...... _..!'.' . avo avo 767 . ' . . ' . g .... 1z gr-1z ' .. ~ .. avo avo 710 • cop 656 500 u '" '" e "' bt 1000 r, 500 "" .., '" e iii 1000 fig. 2 a) interprctation of rap stack section wit h two avo analyses (emp 767 and 710) included: b) inlcrprclation of restricled gmdient slack. red allom;. j i e.~ indicate the potential presence of gas. the basal tertiary is charac terized by a slightly higher amplilude. the gas/watcr cont ac t is re latcd to a mild flat spol the bottom of the gr-iz well is at 790 msec within the tertiary basement. below the botiom of the well, at approx imately 820 msec latera ll y to the well there is a bright spot, whi ch represents a probable lithological change, maybe cvcn an erosional unconformit y, which has not yet bcen renehed by any of the wells. thi s bright spot is weak­ cned in it s centra l part because of the absorption of seismic energy (shadow zonc below bright spot ). on the rap-stack section the in terpreta tion of ek320 geologia croatica 49(2 i i ~ ... ""--_:sonic (usekim) density (!;ci!l) rc avo cop rp :tp'" soo o 1.25 fig.::; comparison of well, seismic data alld schematic lithologic.1i column. legend : i ) mctalllorphilcs (g"<ll1il illica selll),i): 2) bioc;ticirudilc to bioca lcarenit e: 3) sandy argillaceolls marl 10 calcareous clay, c la sti cs and fossil karst fragments: 4) marl and sill y sandstoll e; 5) sil ly to argillaceous marl: 6) argillaceolls marl with sandstone interbeds; 7) marly clay with sand interbeds: r) main reservoir. marke rs: 6., r57, bt and a probable lithological change "x" arc shown. there are a lso two a vo angle trace analyses, on cdi' (common depth point) 767 and 7 10 wilh angles of 8 to 24 degrees, to illustrate ihe possible gas saturations in the sediment complex. figure 2b (restric ted gradient s tack) is d isc ussed below and ind icates that the results of avo analyses of pre-s tack seismic data show good correlat ion with the rap-stack section (fig. 2a) confirming the presence of gas. 3. avo inversion it has been proven that the p-wave reflection coeffi­ cie nt s on the bo undary of two clastic media changc with the angles of incidence, or with the offsets because of the var iolls re lative values of poisson's rat io across the rellect ing interface. these fac ts were al ready noticed on the seismic da ta pri or to s tacking (koefoed, 1955), and were late r confirmed theoretically and by laboratory meas ure­ ment s. the res ults of the laboratory measurements showed that the highly porous, gas saturated sa nd ­ stones, give a vc ry low poisson' s ratio. in the natural underground condition s in sandy sediment s, if gas is present, il is proved that the p-wavc reflect ion coe lti ­ cient increases wilh the angle of incidence (ostran­ der, 1984; domenico, 1976; r utherford & williams , 1989). during the a yo invc rsion procedure special attcn ­ tion should be paid to thc quality of the seismic data , both field rccord ing and during se ismic process ing, becausc they significantly a ffect the recorded re flection amplitudes as a distance funct ion from the source. dur­ ing the survey attention should be pa id to whether the analysed horizons arc at suitable depths, considering ihe di s tance between the source and the receive r; if the re is enough coverage (at least three-fold on target horizons); how the field dala a re affeeted by noisc; and whether the seismic encrgy can be losl during shooling, because of some natural conditions, e.g. weathering zone. generally the following fac tors a ffect a yo inver­ sion s: angles of reflecti on incidence, re flec tor curv ing with sign ificant impact at small depths (il is not recom­ mended to perform the inve rsion up to ,approximately 400 ill), transmission coeffi cien ts, multiples and ine las­ tic smoothings. during the seismic process ing it is impor tant to restore the ene rgy lost wit h time and dis tance, because of the spherical spreading o f wavefronls. the ot her fac­ tors thai affect the relat ive amplitude re lations are: the diminishing of amplitudes because of geophone a rrays and sources, especiall y at shallow depths, whe re the angles o f incidence can be increased, whi le part of energy can be losl because of re fraction. this is why it is not recommended to ana lyse the longer offsets. the same happens for greate r depths at sho j1 offsets. gcner­ ally speaking, vcry shallow and deep reflections are not rel iable for a yo inversions. the next factors affecting ampl itud e re lati ons arc the tuning effects. closely si tuated re fl ec ti ons cannot be expressed on seismics, but thcy merge int o one, which could be anal yzed through the nmo eq uation and by higher seismic resolution (ostrander, 1984; westvidovic, ruk~vina, syrinck, bijelic & milinovic kolundzic' bright spot i\ vo i nvcr~ion and synthetic on 321 q) -0 :~ ci e '" c .g p' u q) ~ sin2~ fig. 4 lincar iii of avo curve of rencclion ampli lude vs. s in ' ~. ern geophys ical:!), these effects in th inner shall ow sands (approx imately 12-15 111 ) can resul t in d imin ish­ ing ampl itudes at greater distances from the source. various no ises can also s ignificantl y afrec t the amplitudes, and in the case of long offsets they can pro­ voke dimi nishing of amplilude, thi s is why analys is or the sin ra ti o (s ignal -to-noise ralio) is recommended. to improve the sin rat io in accordance with the fres­ nel-zone width, the partial averaging of severa l orrsets or sever" l angles was undertaken. it is recom mended to use da ta recorded under the constant cond itions for avo inversion s, wh ile d uring the seismic process ing one should keep to the ehosen processi ng schedule. the most important phases or the processing arc: treat ment of the spherical spread ing or wave fronts, phase correction duc to var iou s recordi ng cond itions, deta iled vcloc ity analyses, deconvolut ion; it is not recommended to pcrform statistica l deconvolu­ tion which may introd uce amp litude and phase varia­ tions . here, surface consistent deconvo lutio n of the spiki ng iype was performed, because the operat ions are separately created: a) operaloi' in the source domain 10 crase the ditterences from source to source, b) opera tor in tllc receiver domain that corrects the contacts during the recordin g rece iver/earth (coupling), c) operator in the comjl1 on offsets domain, to reject reverberations. a ll the figures we re produced wit hout amplitude equa li sati on, so ihat relative energy on all the recorded receivers could remain in rea l lerlll s. fi gure 2a shows the rap-slack display and amplit ude vs, offsets ror two colll mon dept h poinls (cop 767 and 7 10) on the sorted se ismic traces. it should be men tioncd that the a va e ffects acco rd ing to the angle of incidence are more obv iously expressed , than those according to the o frse t. bes ide a va invers ions of seismic data before stacki ng, altribtjl ive stacks were made: grad ient stack and res tric ted gradient stack. gradi ent sl ack g is based on th e principle that the re fl ec tion ampl it ude r(p) of p-waves reflect ed [rom the int erface bct ween two clasti c media, varies linearly wi lh ihe sin 2 p (fi g. 4) accorcii ng to the equat ion: r(p) p + g . sin'p where p is interccpt, p retlection ang le, and g gradient (s lope). the linear fi t o f avo curve of reflection amplitude vs. si n:! p run correctly for refl ect ion ang le p less than 25°, and data must be corrected for sta tics and nmo by carefu lly obtained veloci ties. the values are calculat ed on each seismi c trace before slacking data and for each sampling period. the section of grad ient stack g contains the information on the increase in amplitude changes depending on s i n 2 ~ (oll sels). difrcrelll companies have vari olls programs for analysi ng the am plitude vs, offse t. t he e lement ary a lgorithms arc the same, the dilterences occur in the var ious kinds of representati on and inversion in to attri butes. the restricted grad ient stack gr (fig. 2b) is recommended. this is the grad ient or abso lute ampli ­ tudes depending on sin2p: gr = sgn(p) . g when p and g have the sam e s ign gr is posi tive, when they are opposite signs gr is negati ve. comparing restric ted g radi ent stack gr (fig, 2b) with rap-stack (fig. 2a) showing bright spot indica­ tors on the gr section , there are positive anoma lies (show n in red) when the absolute amplit udes increase with offsets. in a typical sand-marl sequence, the large pos itive anomalies ind icate the potent ial presence of gas. they are relatcd to ihc increase of absolute ampli tudes in re lation to the increased angles, whi le the negat ive amplitudes deny the presence o f gas. on fig, 2 b, red positive amplitudes are s ituated above the main gas accu nlul alion, approximately between 600 and 675 illsec, support ing the above men­ ti olled in terprctal ion of th is compl ex nrea . 4. synthetic logg in g data and veloci ty measurements provided dma for a synthet ic to be created a ft e r the we ll was completcd and logg ing and velocity data became ava il ­ ab le. t he proccdure for the crea tio n of' the synlhet ic enables control of ihe bas ic inte rpre tation assumptions and corrclation of the drilling results, well -log data and seismic profiles. thc curvc correct ion of the sonic log was performed first, the so-called cali bration o f the recorded sonic log wi th the reco rded veloc it y (ve locity surveyor vsp vertica l seismic profiling) . the control point s that are chosen have geological importance and they arc located at lithological changes or stratigraphic boundaries. differences in velocities can appear 1'01' a va riety of reaso ns, such arc the case o f two different so urces of ~ wes lcrn gcophysical (1994): manual s for users, iiclp.unplibi. di sc documentation . :\22 velocity survey. the sonic log integrated travel time, measured on the basis of refraction may not truly reflect the seismic travel time. sonic log integrated veloci ties call diller from the seismic waves velocities, because the frequency of the seismic line is lower and its wave­ length is longer. velocities depend on the places where the gcophones wcre sited in a well. sometimes fractures in formations during the drilling process have a greater effect on seismic velocities than on the sonic log. after the calibration has been performed, the syn­ thetic can be created from the sonic log and the density log transforming them into two-way-time. simultane­ ously the seismic profiles with wells marked on them arc loaded. due to the better coreiation all other avail­ able logs were loaded, while the lithological column according to the lithological profile was compiled (fig. 3) . avo analysis of seismic data cdr 744, from th e nearby well gri z was added to the end of fig. 3. this allows comparison and identificat ion of the horizons on se ismic profiles, logging cu rves and on synthetic. wavelets for convolv ing the reflection coefficients call be for example ricker wavelets, but the correlation wavelet can also be ex trac ted by comparing the seism ic pro riles and reflection coerricients. during this proce­ dure one can indicate the need ror corrections of the seismic profiles, sonic log or velocity survey . during the study of al l these comp iled data, the problems or phase corrections can be exp lain ed, and also the time shifts in se ismic data, and lithological impacts, which can be dillerent on th e synthetic and the surface seismic. t he problems during the seismi c processing can be defined and any requirement for the reprocessing of seismic profiles can be indicated. on the examp le of the well gr-i z there was no need ror the correction of seismic profiles, because they were especially reprocessed for the needs of avo. the syn­ thetic was formed with the ri cker wavelet, which rep­ resents the real picture of th e synthetic seismogram. small discrepancies are explai ned in the interpretat ion, according to the well data and the complexity of th is gas accuillulation. lr the synthetic is shifted along th e profile to the well, the stratigraphic continuity can be followed dur­ ing the process or extracting the correlation wavelet, as a better or weaker correlation. 5. conclusion bright spots enabled the definition of gas accumula­ tions along with the usual interpretation methods. the difference between gas accumulat ions and lithological changes can be identified by the avo analysis inver­ sion or se ismic data, and this also contributed to the more rational colllouring of the gas accumulation and to the well location. in the complex subsurface geo logy a yo methods can be unreliable, whilc the results of these analyses geologia cromiea 49/2 must be in terpreted very careful ly, so the impact or local changes in geology can be separated frolll the anomalies of the amplitudes related to the source­ -receiver distance. it is important to mention that these methods must be confirmed by other methods, and the results illust be reviewed in terms of the problems of the exploration area. due to explanati on of this complex gas accuillula­ tion, we include all the well data, thnt in the seism ic section along with bright spots contains also dim spots. this can also point 10 any need for reprocessing and correction of seismic data, and more accurate contour­ ing of the reservoir in the vertical and horizontal sense. if the various data are wei! correlated, they represent and confirm the in terpreta tion and indicate other favourable drilling locations. in all, thi s is a contribu­ tion toward more rational exploration and has a positive impact on business decisions. the processings was performed with the programs or western geophys ical and western at las companies on ibm risc-6000. 6. references domenico. s.n. (1976): enloct of brine-gas mixture on velocity in an uncosol idated sand reservoir.­ geophysics. 41, 882-894. koefoed, o. (1955): on the elleet of poisson's ratio of rock strate on the relleclion coefficient of plane waves.geophysical prospecting, 3, 38 i -387. ostrander,w.j. (1984): p lane-wave reflection coefficients for gas sands and nonnormal angles of incidence.gcophysics, 49/10, 1637-1648. rutherford, r.s. & w1lllams , r.h. (1989): amplitude-ve rsus-offset variat ions in gas sands.­ geophysics, 54, 680-688. perica.indd 271 � ab stra ct the peak areas of the velebit mountain range display an interesting periglacial geomorphology. the appearance of forms is the result of the interdependent geological, geomorphologic, climatic, vegetational and pedological characteristics of the area. the structural and lithological properties of the rock complex, and the inclination of the slope, play a signifi cant role in periglacial relief modelling. climatic elements are also important, as they infl uence the intensity and duration of the processes. low temperatures and relatively high precipitation during the last ice age (würm iii), served to intensify the activity of periglacial processes and relief modelling of the entire velebit area. nivation and cryofraction are the predominant periglacial processes which are represented by snow avalanches and stone streams. air temperatures and soil temperatures (at 30, 60, 90 cm depth) were measured, presented and reviewed, together with other attributes and the slope inclination of the area. the interactions between ground temperature, snow cover and wind patterns play important roles in frost action. in addition to slope inclination, the penetration of warm winds (jugo) and warming of snow on the ne slopes are also important factors in destabilizing the snow cover and triggering avalanches. snow avalanches are most intensive on slopes with declinations from 35° up to 50°, especially on the parts without vegetation cover. keywords: nivation, cryofraction, periglacial relief, velebit mt., croatia the infl uence of nivation and cryofraction on periglacial relief formation on velebit mt. (croatia) � dražen perica, nina lončar and sanja lozić department of geography, university of zadar, p. svačića 9, 23 000 zadar, croatia; (dperica2001@yahoo.com) doi: 104154/gc.2010.22 geologia croatica 63/3 271–282 12 figs. 4 tabs. zagreb 2010 geologia croaticageologia croatica 1. introduction the velebit mountain range extends along the adriatic coast in a nw-se direction. with its surface area of 2 359 km2 and length of 145 km, it is the longest mountain range of the dinaric mountain belt in croatia (figure 1). in the peak areas of the velebit range (higher than 1400 m), beside karstic and slope processes, periglacial processes have also played a great role in shaping the relief. their appearance is the result of the interdependent geological, geomorphological, climatic, vegetational and pedological characteristics of the area. due to the specificity of the microclimate, predominantly marked by thermal inversions, periglacial processes can sporadically occur at altitudes of about 1000 m. relief forms created by the infl uence of snow and cryogenic processes can be singled out. during the pleisgeologia croatica 63/3geologia croatica 272 tocene, cryogenic processes infl uenced relief modelling in the middle and lower parts of the slopes. in the shaping of relief by periglacial processes, anthropogenic and zoogenic infl uences have had a signifi cant role, especially evident in peak areas where pinus mugo dominates. 2. previous research though the velebit range had already attracted naturalists studying landforms in the late 18th century (hacquet, 1785), it was not until the mid 20th century that poljak (1947) and rogić (1958) pointed out the issues of periglacial relief formation on mt. velebit. however, these scientists focused their studies on the deglaciation of velebit (or its non-existence, (poljak, 1947) and regional issues (rogić, 1958), while periglacial processes and their modelling were only considered superfi cially. the fi rst person to study recent and pleistocene periglacial relief formation in the velebit region was belij (1985). within regional geomorphologic researches, bognar (1992, 1995) and bognar & blazek (1986) identifi ed the signifi cance of periglacial relief formation in the peak regions of velebit. perica et al. (2002) also studied the pleistocene and recent periglacial infl uence on relief modelling. marjanac & marjanac (date) examined the glacial history of the croatian adriatic and coastal dinarides, including velebit mt. a number of papers deal with the glacial history of the mediterranean mountains, the results of which can be applied to velebit (hughes & woodward, 2008; hughes et al., 2007; hugher et al., 2006; federici, 1980; kotarba et al., 2001; dramis & kotarba, 1994; viera et al., 2003). finally, there are some relevant works on modern glacial environments in slovenia (the triglav glacier, gabrovec (1998)) and montenegro (the debeli namet glacier, hughes (2007; 2008)). geobotanical (horvat, 1949), pedological and climatological papers had a signifi cant impact on the research of recent periglacial processes and relief modelling in the velebit mt. region. among the authors studying climate characteristics on velebit which had signifi cant impacts on research into periglacial relief formation, the following must be noted: rogić (1958), kirigin (1967), bertović (1975, 1980), and perica & orešić (1997). 3. methodology given the topic of this paper, the research was based on fi eld work, with supplementary quantitative geomorphologic methods. during fi eldwork, consideration was given to the impact of snow, ice and wind on slopes of varying exposition and steepness, and to the differences in microforms created as a result of the interdependence of these factors. climatological data (air temperature, precipitation and wind) of the state hydrological and meteorological institute were used for the period from 1981−2000. microclimatic measurements of soil temperature were performed between december 2003 to august 2005, near the zavižan meteorologi cal station. soil temperature was measured with bimetal geo thermometers at depths of 30, 60 and 90 cm below ground. gis analysis of slope of the area in question (peak areas of southern velebit) was applied during quantitative geomorphological analysis. 4. results and discussion the structural properties of the rock complex, i.e. the density of primary and secondary fi ssures and hollows, and the inclination of the slope, play a signifi cant role in periglacial relief modelling. though carbonates (limestones and dolomites), with layers dipping seawards (to the sw) are frequent throughout the velebit range, these dominate in the peak regions (higher than 1200 m). the frequency of appearance of primary fi ssures is exceptionally high in “clastic” carbonate deposits of tertiary age known as breccia in the highest parts of velebit. in layered rocks (limestones and dolomites) with primary fi ssures, which include the highly signifi cant diastromic (or interlayer) cracks, tectonic movements have created numerous smaller secondary fi ssures. the existence of these fi ssures has helped strong cryogenic destruction of the rock complex in the peak areas of velebit, and also on the lower slopes. in the colder months (below freezing point), ice in the fi ssures acts on the rock surface, creating mechanical wear. 4.1. the infl uence of climate on periglacial formation of the relief climatic elements are important, as they infl uence the intensity and duration of periglacial processes. the boundary position of velebit between the coast and the interior is best seen in the climatic properties of the upper ridges. the velebit mountains prevent the mixing of the lowest layers of air on either side to an altitude of 1000 m. the southwestern (coastal) slope is subjected to maritime infl uences, while the northeast is subjected to continental conditions, thereby creating signifi cant differences in temperature, relative humidfigure 1: position of velebit mt. (croatia). perica et al.: the infl uence of nivation and cryofraction on periglacial relief formation on velebit mt. (croatia) geologia croatica 273 ity, wind (amount and speed), cloud cover and precipitation (penzar & penzar, 1995). the thermal maritime infl uence is limited to a narrow coastal band, and the central parts of the southwest velebit slopes (up to approximately 900 m in altitude), which is best seen in the vegetation cover. this belt is virtually completely dominated by submediterranean vegetation. in the coastal regions, the mean annual temperature fl uctuates around 15ºc. the winters are mild, with an approximate temperature of about 6.5ºc in the coldest month (january). due to the exceptionally small number of cold (around 18) and icy (around 2) days, the infl uences of cryogenic processes are negligible. furthermore, cold and icy days in the coastal regions primarily appear during periods of the strong northern wind bora, which brings rapid drying and evaporation of the bare carbonate surfaces that dominate on the southwestern slopes, thereby preventing the possible creation of ice in rock fi ssures and its mechanical action. with increasing altitude, the air temperature drops rapidly on the south-western slope. during the colder part of the year, cold, icy and chilly days are common in the higher regions of velebit (above 900 m), which causes freezing of water in rock fi ssures and the appearance of cryogenic processes. heavy orographic precipitation is characteristic of this region due to the exposure of velebit to the warm and moist south-westerly air currents from the sea. the lowest amount of precipitation is recorded in the coastal areas (about 1200 mm annually). precipitation increases with increasing altitude, though this is uneven. the lowest precipitation occurs on the sw slopes of northern velebit, where the precipitation isoline of 2000 mm is at altitudes of about 1400 m. in the area of central velebit, annual precipitation is markedly higher, with the precipitation isoline of 2000 mm, gradually dropping to an altitude of 900 m on the nw slope, i.e. to the very bottom of the poljes on the ne slope. the highest level of precipitation (greater than 2500 mm) is recorded in the peak areas of southern velebit, particularly at its lee on the ne slope (visočica 2883 mm; bunovac 3419 mm). furthermore, in southeastern velebit, the quantity of precipitation drops to less than 2000 mm per year at 900 m altitude. in the velebit region, there is more precipitation in the colder part of the year. all rain measurement stations record the highest precipitation in the fall months, with a secondary maximum in the spring. snow is least frequent along the coast (around 0.3 days) and on the lower parts of the sw slope, while the number of snow covered days increases with altitude. on the ne slope, the duration of snow cover is also lowest at the base of the slopes (71 days at altitudes up to 600 m), while areas between 700 1000 m (the peak areas of velebit) are covered in snow up to 95 days. at the zavižan meteorological station, snow cover of 1 cm or more was recorded for 166.8 days of the year, while a deeper snow layer of 50 cm or more was recorded for 97.8 days of the year. snow retention is signifi cantly longer in the forests than in the open areas, and also on the sw slopes rather than ne slopes, particularly at the bottom of deep depressions where it is carried by the wind, and at the base of avalanche areas. in areas with an inclination exceeding 50°, snow is not retained at all, but immediately falls to lower areas (šegula, 1986). due to a lack of snow that would act as a thermal insulator, the peak areas are subjected to strong frost wear and periglacial relief modelling. in contrast, where the snow cover is retained for longer periods of time, its thermal insulation effect prevents a higher level of cryogenic processes in such areas. the entire velebit area is infl uenced by continental winds, of which the most important and strongest (up to 200 km/h) is the bora, a cold and dry northern wind, blowing mostly over the sw slope. in winter, the wind blows the snow cover away at saddles and cols in the ridge and on parts of the bare sw slope, thus creating snow deposits at more inclined and protected locations. the jugo (southern wind from the sea), is the most important of the maritime winds. it collects much moisture during its passage over the mediterranean and adriatic seas. upon reaching the dinaric mountain range, the wind is forced to rise, which is accompanied by a drop in temperature, increase in relative humidity, cloudiness and precipitation, while on the ne slopes, it frequently has the character of a warm and dry air stream (makjanić, 1978). as a result, in the winter, the jugo causes sudden snow melt followed by snow avalanches, even in the peak areas of velebit. generally speaking, due to the specifi c climatic position, the peak areas of velebit are characterised by constant air currents, accompanied by relatively strong winds (zavižan, 3.2 on the beaufort scale). thus, despite the signifi cant snowfall, large areas in the peak region of velebit are bare in winter, without snow cover, thereby stimulating frost weathering. it is important to discover and determine the connections between air temperature, duration and amount of snow cover, soil temperature, and their impact on periglacial processes. therefore,soil temperature was measured at depths of 30, 60 and 90 cm, between december 2003 and august 2005, near the zavižan meteorological station. daily readings were taken at 7:00 am, 2:00 pm and 9:00 pm for both air and soil temperatures. air temperatures in 2004 and 2005, from 1st january to 20th march, (table 1) were below 0°c. such temperatures produced soil freezing to a depth of 30 and 60 cm and there were evident differences between air and soil temperatures (table 1, 2; figure 2, 3). such values are connected with snow maintenance and depth of cover (snow cover as a thermal insulator, table 3, 4; figure 4, 5). however, in areas where the bora wind carried the snow away, and removed its thermal insulation properties, more pronounced frost processes operated. the climatic characteristics of velebit during the last ice age (würm iii) also had a great role and effects on periglacial relief modelling. some authors consider that traces of the last glaciation in the velebit region date back exclusively to the würm glaciation, which was quite extensive (belij, 1985; bognar et al., 1992, 1997; nikler, 1973, perica & orešić, 1997). marjanac & marjanac (2004.) geologia croatica 63/3geologia croatica 274 figure 2: comparation of air and soil temperature from december 2003 to may 2004 on zavižan (1594 m). table 1: the middle monthly air temperature and soil temperature by date and depth – december 2003 to may 2004 on zavižan (1594 m). period december 2003 january 2004 february 2004 march 2004 april 2004 may 2004 soil depth cm 1-10 11-20 21-31 1-10 11-20 21-31 1-10 11-20 21-31 1-10 11-20 21-31 1-10 11-20 21-31 1-10 11-20 21-31 30 2.0 1.0 0.1 -0.7 -0.2 0.0 0.0 0.0 0.0 -0.2 -1.0 0.0 0.0 0.0 0.7 1.0 1.2 5.8 60 2.8 2.0 2.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -0.5 -1.0 0.0 0.0 0.0 0.0 0.2 4.0 90 4.0 4.0 3.4 3.0 3.3 3.0 3.0 2.6 2.0 2.0 1.0 1.0 1.0 1.0 0.3 0.0 0.0 3.3 air temp°c -1.9 -2.2 -4.6 -7.1 -2.3 -12.3 2.7 -6.5 -4.1 -7.5 -2.1 -2.1 1.7 0.9 2.4 2.3 4.2 4.8 suggests that the most extensive glaciation was much older than the würm and reached low altitudes on the piedmont and even below sea level. they noted that the würm glaciation was restricted to the higher valleys and cirques. elsewhere in the balkans, it also appears that the most extensive glaciations occurred during the middle pleistocene, which would have had a big impact on periglacial processes and landform development in the velebit (hughes et al., 2006, 2007). some discussion on the age of glaciations from montenegro also suggests a middle pleistocene age for the oldest and most extensive glacial deposits in this region (hughes & woodward, 2008). according to some authors, the most extensive glaciations in the italian apennines also occurred during the middle pleistocene and were bigger and more severe than that during the würm (federici, 1980, kotarba et al., 2000). many authors studying climate during the last ice age consider that the air temperature was lower by 10 to 15ºc. table 2: the middle monthly air temperature and soil temperature by date and depth – december 2004 to may 2005 on zavižan (1594 m). period december 2004 january 2005 february 2005 march 2005 april 2005 may 2005 soil depth cm 1-10 11-20 21-31 1-10 11-20 21-31 1-10 11-20 21-31 1-10 11-20 21-31 1-10 11-20 21-31 1-10 11-20 21-31 30 3.0 3.4 1.0 1.0 1.0 0.3 0.0 -0.4 -1.0 -1.8 -1.9 -1.3 3.0 4.4 6.7 11.5 16.2 17.6 60 2.0 2.0 2.0 2.0 2.0 1.5 1.0 1.0 0.0 -0.4 -1.0 -1.0 -0.1 0.4 2.3 3.2 4.0 5.6 90 4.0 3.7 3.0 3.0 3.0 2.8 2.0 1.7 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.5 2.8 3.7 air temp°c 2.8 -1.4 -4.9 -1.1 -4.6 -15.1 -8.9 -6.9 -8.1 -11.4 -0.7 2.0 0.2 -0.2 2.4 5.1 4.6 11.3 perica et al.: the infl uence of nivation and cryofraction on periglacial relief formation on velebit mt. (croatia) geologia croatica 275 figure 3: comparation of air and soil temperature from december 2004 to may 2005 on zavižan (1594 m). šegota (1963) assessed that mean air temperatures in july during the peak of glaciation were lower by 10–12ºc, riđanović (1963) by 10ºc, and gates (1976) by 14–15ºc. based on studies of periglacial processes and forms in the pannonian lowland, poser (1947) stated a mean annual temperature of -2ºc. therefore, the mean july temperatures obtained here correspond with those of the map created by gates (1976). according to šegota (1982), increased atmospheric circulation at the start of glaciation caused a reduction in precipitation by at least 20%, with solid precipitation being dominant. later, due to reduced evaporation of the sea caused by low temperatures and expansion of the ice shield, the quantity of precipitation decreased to its minimum at the period of maximum glaciation (šegota, 1963; šegota & filipčić, 1996). due to the proximity to the sea and fafigure 4: amount of snow from december 2003 to may 2004 on zavižan (1594 m). geologia croatica 63/3geologia croatica 276 figure 5: amount of snow from december 2004 to may 2005 on zavižan (1594 m). table 3: amount of snow in cm december 2003 to may 2004 on zavižan (1594 m). december 2003 january 2004 february 2004 march 2004 april 2004 may 2004 1-10 11-20 21-31 1-10 11-20 21-31 1-10 11-20 21-31 1-10 11-20 21-31 1-10 11-20 21-31 1-10 11-20 21-31 4 3 32 39 57 92 82 73 98 17 163 137 104 132 93 40 11 1 source: croatian meteorological and hydrological service archives table 4: amount of snow in cm december 2003 to may 2005 on zavižan (1594 m). december 2004 january 2005 february 2005 march 2005 april 2005 may 2005 1-10 11-20 21-31 1-10 11-20 21-31 1-10 11-20 21-31 1-10 11-20 21-31 1-10 11-20 21-31 1-10 11-20 21-31 0 5 27 37 26 97 123 122 163 188 163 88 30 55 20 0 0 0 source: croatian meteorological and hydrological service archives vourable air currents, velebit received a relatively large amount of snow. according to klein (1953), during the coldest period of the würm glaciation, there was 20% less snow on the southern velebit and 40% less snow on the northern velebit. low air temperatures and relatively high quantities of precipitation during the würm glaciation were suitable for maintaining glaciers at higher altitudes and snow cover at lower altitudes, resulting in intensive periglacial processes throughout the velebit area. according to bognar (1992), intense frost damage is particularly evident in the destruction of early created karst microrelief forms (karren) in the central and lower parts of the sw and ne slopes. 4.2. the infl uence of slope inclination on periglacial formation of the relief as a quantitative geomorphologic parameter, slope inclination has an important role in periglacial formation of the relief (figure 6.). the characteristics of slope inclination enable estimation of the character, volume and intensity of periglacial processes. snow avalanches are most intense on slopes with inclinations from 35° up to 60°, as on the ne slopes of the highest areas of velebit, especially on those without vegetation cover. alternatively, in the areas with inclinations between 15 and 35°, the snow glides and forests partly prevent the development of snow avalanches. slopes with inclinations over 50° comprise a small part of the reperica et al.: the infl uence of nivation and cryofraction on periglacial relief formation on velebit mt. (croatia) geologia croatica 277 figure 6: inclination map of researched area (velebit mt., croatia) with locations of fi gures 8-12. search area but on these slopes the snow is instantly blown away and cryogenic processes are more signifi cant (due to the absence of snow as a thermal insulator). sometimes where slopes are below 15°, the fragmented materials formed by nival and cryogenic processes, move more slowly. on steeper slopes, (with inclinations over 35°) rock collapse is present. collapse processes are most significant on slopes with inclinations over 50°, such as on the sides of the canyons of velika and mala paklenica, the golovrh area (1368 m) and the area southeast of m. visočica (1545 m), veliki orljak (1324 m), the southwest slope of kozjak (1572 m), northeast slope of šiljevača (1449 m), badanj (1638 m, no. 10, fig. 6, 7), northwest area of vaganski vrh (between štirovac and vaganski vrh, no. 8, fig. 6, 7), the area south and southwest of debelo brdo (1632 m) and vaganski vrh (1757 m): buljma, brezimenjača, jerkovac, the area north of jelovi tavani (1223 m), north slope of jelov vrh (1227 m), a small part of northeast canyon of mala paklenica, tulove grede area (1120 m), and several smaller areas. 4.3. the infl uence of nivation and cryofraction on relief modelling periglacial processes have a signifi cant impact on relief modelling of velebit. they often appear in the highest altitudes but, due to specifi c microclimatic conditions (thermal inversion) these can sporadically appear at lower altitudes. movement of the snow cover is seen on the slopes of the peak regions. on slopes covered with forest vegetation, and on bare slopes with an inclination of less than 35°, the snow cover usually creeps. where such slopes have forest vegetation, the tree trunks bend at their base (bertović, 1975; 1980). this is particularly evident in the beech forests (fagus sylvatica) in the foothills. due to the long period of snow retention and its depth, low forest vegetation (pinus mugo) dominates in the highest altitudes of the southern part of velebit. the average monthly number of days with snow on the ground at ≥ 1 cm depth is 166.8 days, and for depths ≥ 50 cm it is 97.8 (as measured at zavižan meteorological station between 1981 and 2000). on unforested slopes with an inclination > 35°, snow avalanches are common. avalanche processes occur in two ways: the fi rst is related to linear snow movements from the slope, which form avalanche trenches (corridors), while the second appears when the snow avalanche covers a large part of the slope (surface avalanche). snow falling on steep and shaded slopes in peak regions with an inclination greater than 60° instantly moves downslope (šegula, 1986). this is often directed into the somewhat gentler, trenches and valleys where the snow accumulates (figure 8) and, due to the large inclination (between 35° and 60°), this moves in the form of a snow avalanche to the base of slope regions. there are many such corridors and valleys in the peak regions of the ne slopes, among which the following are particularly signifi cant: the trench between vaganski vrh (1757 m) and the point 1723 m towards basins vaganj (figure 9) from vaganski vrh to the fold on the ne slope above the vaganac sinkhole and from the direction of dolina cesarova and the ne slopes of malovan (1709 m) to the bunovac basin. on the sw slope, the most prominent are the steep valley (former glaciated valley) between crljeno (1616 m) and babin kuk (1435 m). smaller avalanches also appear in the gullies on the steep, shady slopes of badanj (1638 m), geologia croatica 63/3geologia croatica 278 visočica (1616 m) and golovrh (1584 m). these are avalanches with exceptionally important impacts. the avalanches move at high speed in the lower parts, encountering forests and destroying trees. considering that many trenches can also act as funnels, carrying the karst rock and even rock slabs with a volume exceeding 1 m3, they form avalanche corridors (figure 9). at the base of steep ne slopes, avalanche deposits in the form of large compacted snow masses accumulate on gentler slopes (figure 8). unlike the avalanches from trenches and valleys, surface avalanches covering a large area of the slope occur on the steep slopes of the peaks and on the sides of the deep sinkholes. these avalanches are the result of instability due to large accumulations of snow on gentle slopes that represent figure 7: topographic map of researched area (velebit mt., croatia) with locations of fi gures 8–12. figure 8: the avalanche accumulation. local denudation bases. depending on the time of the critical point when, due to the effect of gravitation, the internal cohesion of the snow mass is lost, the mass either cracks or separates in line with its mass and the inclination of the slope and collapses down the face of the slope. snow carried by such avalanches accumulates in the bottom of basins, deep sinkholes and in the foothills of the peak slopes. this kind of avalanche is most prevalent on the ne slope of sveto brdo (1751 m). in addition to inclination, the penetration of warm winds (jugo) and warming of snow on the ne slopes are also important factors in destabilizing the snow cover and triggering avalanches. an increase of snow temperature to 0°c causes weakening of internal cohesion within the snow mass, and results in its ultimate collapse down steep slopes (šegula, 1986). such avalanches are common on the grass covered slopes of the peaks and the sides of sinkholes and basins (on the southern slopes of sveto brdo, badanj and debelo brdo, fig. 10). due to the specifi c microclimatic conditions at the base of individual depressions, and in areas where avalanche snow is deposited, large snow masses (snowfi elds) form at the base of the ne slopes. the creation of large snow masses in sinkholes and basins is the result of wind removal of snow from the ridge and those exposed parts of the slope. the bases of sinkholes and basins are in shade virtually all year round due to their depth. this causes a strong thermal inversion and ensures snow retention until mid summer. the most pronounced example of an accumulation is in a sinkhole nw of vaganski vrh (1757 m) at an altitude of 1680 m. such snow masses, formed by the mechanical and erosive? impacts of the snow, the water (from snow) and ice, acts to break down perica et al.: the infl uence of nivation and cryofraction on periglacial relief formation on velebit mt. (croatia) geologia croatica 279 the soil substrate, both expanding and deepening the bottoms of the sinkholes and basins, creating nivation niches. also, due to suffosion activity, the snow masses create niches with a semi-circular shape, arranged in step-wise sequences on the slope. such forms are described by gutiérrez (2005). there are many such step-like indentations on the upper parts of southern velebit, and these often appear at lower altitudes (about 1000 m, i.e. sladovača) on the shaded and sw sides of the depressions. certainly, the most pronounced of all the periglacial processes is the cryogenic process, including cryofraction and cryoturbation (the stone sea near struge, fig. 11). these are very common in the peak areas of velebit. the average air temperature of -3°c at zavižan peak, during the winter period (december to march) maintains the periglacial processes. the very small fl uctuation around 0°c in day and night temperatures during spring and fall causes the water in fi ssures to thaw and refreeze, thus resulting in powerful frost destruction of the rock complex. microclimatic measurements of summer air temperatures 5 cm above the ground in the modrić dolac sinkhole on northern velebit near the zavižan meteorological station (1594 m), and at a site 74 m lower, confi rms that the temperature in the mat grass community is 10 to 12°c lower (dropping to -6°c) than at the meteorological station itself (kirigin, 1967). it is important to mention that in many depressions, temperatures are often much below average. such values are shown in the results of microclimatic measurements of air temperature performed in depressions of the dinaric regions of slovenia (at altitudes between 700 and 1000 m) where the minimum temperature measured was from -25°c to -30°c, as a result of thermal inversions (ogrin et al., 2006). as such, it can be concluded that cryogenic processes in the sinkholes and basins of the peak areas of southern velebit, also overgrown with mat grass, are very prevalent in the summer months. according to belij (1985) and bognar & blazek (1986), a large quantity of cemented slope material in the valleys of the velika and mala paklenica creeks, clearly indicate the intensive cryogenic processes that took place during the pleistocene. according to bognar (1992, 1995) in the dry-cool climate of the pleistocene period, cryofraction and nival processes, and pronival solifluction (christiansen, 1998) played important roles in the shaping of soils in the velebit area. the fracturing of karst fragments, which continue to crumble as they fall, created colluvial talus and fans at the base of steep shady slopes. an exceptionally good example of frost destruction created by colluvial fans occurs on the sw slope of the peak part of the velika paklenica valley, and below the ne slope of the badanj (1638 m; figure 10) babin vrh (1725 m), and sveto brdo (1751 m) peaks. on the steep sides of basins and sinkholes, and on the slopes of the highest peaks in southern velebit, the karst fragments move slowly down slope due to alternative freeze − thaw processes, creating rock streams. rock streams also fi ll the bottom of the funnel-like sinkholes. on gentler slopes, there are large areas covered with fragmented rock due to the lesser possibility of movement of frost-eroded karst and its further crumbling by frost action. these are known as blockmere, and one example is found on the struge plateau (figure 11). due to the seasonal freezing of water, on horizontal and slightly inclined terrain, there is an alternation of swelling and settling of the soil. if the soil contains fragmented rock figure 9: the veliki vaganac uvala (south velebit) with vegetational inversion (the consequence of the nival avalanches). figure 10: badanj – talus slope. geologia croatica 63/3geologia croatica 280 material, then this is forced up to the surface, where it is further fragmented and sorted. the fragmented rock is forced to the surface, and rips the grass cover, creating new cracks. further freezing and thawing causes these cracks to expand and fragments of the karst rock accumulate within, surrounded by individual clumps, thus creating polygonal soils (stru ge area, uvala javornik). on steeper slopes, the freezethaw results soil creep. if the terrain is covered with grass, the karst fragments forced into the ground and later forced to surface, break through the grass cover. the inclination of the terrain infl uences the collection on the lower part, simultaneously stretching in the upper part of the grass cover, thus creating gelisolifl uction tongues which descend down the slope. on slopes with a higher inclination, growth of grass cover and the formation of vegetational terracotta is somewhat faster. following thermal inversions in depressions and the removal of snow by wind, polygonal soil, migrating grass hummocks and terracotta appear at a substantially lower altitude (in the area of sladovača and kuk stap at 1000 m). today, snow and ice are largely signifi cant in the shaping of speleological objects in the peak areas of velebit (approximately above 1000 m). it is common that dolines and caves, or their entry areas, in the higher altitudes of velebit are fi lled with snow and ice year round due to the specifi c position of their entrances and channels, and the low temperatures within (figure 12). the size and volume of these areas and the complete fi lling of these objects is, as a rule, larger than those without snow and ice. this is the result of intensive frost wear of the rock complex (garašić, 1986). traces of frost action occurring during colder geological periods are evident in some speleological objects (puhaljka pit, a sinkhole at grgin brijeg, a cave near bačić kuk and at crni dabar) (malinar, 1984, garašić, 1986). during the pleistocene, periglacial processes were dominant in relief modelling in those parts of velebit that were not subjected to glacial modifi cation. the formation of dry, hanging valleys and blind valleys in the velebit area is primarily related to the complexes of partially permeable and partially impermeable rocks, in the conditions of the moister and colder periods of the pleistocene. during the fi rst half of the cooling phase, which marked an increase in precipitation levels, their formation was accelerated by the gradual increase of subterranean waters in the fi ssure systems and surface water fl ow. however, in the second phase of cooling, which was marked by a pronounced drop in air temperature and reduced precipitation levels, periglacial disintegration and the creation of permafrost became more dominant in the creation of dry valleys. disintegration was most intense on the dolomite and dolomitic limestone, where a thick cover of relatively impermeable material resulted. this facilitated the formation of creeks, both intermitent and permanent (babrovača in northern velebit, or stap–sjauševac in southern velebit). the presence of permafrost is particularly important in the modelling of valleys on permeable limestone complexes, as this prevented subterranean water drainage. however, upon warming, when a moderate dry and semi-dry climate began to predominate (at lower and middle altitudes), the permafrost melted. both periglacial processes in relief modelling and valley formation ceased. identical conditions also facilitated the formation of hanging and blind dry valleys. the lower ends of hanging valleys are usually cliffs (lički doci), while blind valleys usually form sinkholes at their ends. during the period of maximum cooling, the exceptional domination of glacial and periglacial processes, resulted in numerous openings and channels of cave objects that served as sinkholes (i.e. at the end of blind valleys, sinkholes and uvalas), being fi lled with evacuated materials (bögli, 1980; ford & williams, 2007). this is also seen by the glaciofl uvial sediments discovered in the puhaljka pit (malinar, 1984). 5. conclusion periglacial processes are very important in relief formation of the highest parts of velebit. their appearance is controlled by the interdependence of physical and geographical features of the area, and it is the result of morphological formation and domination of carbonate rock complex. it is possible to isolate the relief forms that were modelled by the infl uence of nival and cryogenic processes. figure 11: the stone sea near struge. figure 12: ice cave near struge. perica et al.: the infl uence of nivation and cryofraction on periglacial relief formation on velebit mt. (croatia) geologia croatica 281 during the pleistocene, cryogenic processes had an impact on the relief formation of the central and lower slopes of velebit. though they have been associated mostly with the higher parts of velebit, due to specifi c microclimatic conditions (thermal inversion) they also occur sporadically in the lower parts (at about 1,000 m). it is important to emphasize the long-term negative anthropogenic and zoogenic infl uences, which are particularly refl ected in the destruction of primary vegetation cover. consequently, these changes affected the modifi cation of microclimate, so that contemporary periglacial processes are more prevalent. considering the length of velebit (145 km), its surface (2359 km2) and the complexity of periglacial processes, it is necessary to conduct further research concerning the geologic, geomorphologic, climatic, vegetational and pedological infl uences on relief formation. also, is necessary to emphasize the importance of quantitative geomorphologic analysis in studying periglacial process and relief forms. knowing the quantitative geomorphologic features of the researched area (slope inclination, and other quantitative parameters, such as relative elevation, slope length, slope aspect etc.), enables us to evaluate the possible locations where nival and cryogenic processes may occur, as well as their characteristics, volume and intensity. therefore, it is necessary to conduct further detailed research of the velebit area, based on statistical analysis of a greater number of quantitative geomorphologic parameters, which would ultimately provide guidelines for further fi eld research. references bakšić, d. (1997): ono što (ne)znate o lukinoj jami [things you do(n’t) know about luka’s pit – in croatian].– speleozin, 7, 12–17. belij, s. (1985): glacijalni i periglacijalni reljef južnog velebita [glacial and periglacial relief of southern velebit mountain – in croatian].– posebna izdanja srpskog geografskog društva, beograd, 61, 1–68. bertović, s. (1975): ekološko-vegetacijske značajke okoliša zavižana u sjevernom velebitu [ecological – vegetation characteristics of zavižan environment in northern velebit mountain – in croatian].– glasnik za šumske pokuse, 18, 5–75. bertović, s. (1980): neke vegetacijske i klimatske značajke lokaliteta u visokom gorju i sredogorju alpsko-dinarskog masiva [some vegetation and climate characteristics of sites in high and middle moun tains of alpine – dinaric massif − in croatian].– šumarski list, 3–4, 99–116. bognar, a. (1992): pedimenti južnog velebita [the pediments of sou thern velebit mountain – in croatian].– geografski glasnik, 54, 19–32. bognar, a. (1995): fragen der rumpffl achen und pedimente im gebiet der ausseren dinariden.– mitteilungen der österreichischen geographischen gessellschaft, 137, 161–170. bognar, a. & blazek, i. (1986): geomorfološka karta područja v. paklenice 1:25000 [geomorphological map of v. paklenica area – in croatian].– simpozij o kraškom površju postojna 1985.– acta carstologica, 14–15, 197–206. bognar, a., faivre, s. & pavelić, j. (1992): glaciation traces on the north velebit mountain.– in: bognar, a. (ed): proc. intern. symposium geomorphology and the sea and meeting geomorph. comm. carpato-balkan countries, mali lošinj, 283–287. bögli, a. (1980): karst hydrology and physical speleology.– springer verlag, berlin, new york, 284 p. christiansen, h.h. (1998): nivation forms and processes in unconsolidated sediments, ne greenland.– earth surface processes and landformes, 23/8, 751–760. croatian meteorological and hydrological service archives 1. 1. 1981 – 31. 12. 2000. & 1. 12. 2003 – 31. 08. 2005. dobinski, w. (2005): permafrost of the carpathian and balkan mountains, eastern and southeastern europe.– permafrost and periglacial processes, 16, 395–398. dramis, f. & kotarba, a. (1994): geomorphological evidences of high mountain permafrost in central apennines.– geografi a fisica e dinamica quaternaria, 17, 29–36. federici, p.r. (1980): on the riss glaciation of the apennines.– zeitschrift für geomorphologie, 24, 111–116. ford, d. & williams, p. (2007): karst geomorphology and hydrology, 2nd edition.– john wiley & sons, ltd., chichester, 562 p. gabrovec, m. (1998): the triglav glacier between 1986 and 1998.– geografski zbornik, 38, 89–110. garašić, m. (1986): hidrogeologija i morfogeneza speleoloških objekata u kršu sr hrvatske [hydrogeology and morphogenesis of speleological objects in croatian karst – in croatian].– phd thesis, university of zagreb, 159 p. gates, w.l. (1986): modeling the ice-age.– climate science, 191, 1138–1144. gutiérrez, m. (2005): periglacial landforms.– in: schröder, j.f. (ed): climatic geomorfology. elsevier, new york, 171−208. hacquet, b. (1785): physikalisch-politische reise auf den dinarischen, durch die julischen, carnischen, rätischen und die norischen alpen, im jahre 1781. und 1783. unternommen. bd. i, ii, leipzig. horvat, i. (1949): nauka o biljnim zajednicama [the science of plant communities – in croatian].– zagreb, 261 p. hughes, p.d., woodward, j.c., gibbard, p.l., macklin, m.g., gilmour, m.a. & smith, g.r. (2006): the glacial history of the pindus mountains, greece.– journal of geology, 114, 413–434. hughes, p.d. (2007): recent behaviour of the debeli namet glacier, durmitor, montenegro.– earth surface processes and landforms, 32, 1593–1602. hughes, p.d., woodward, j.c. & gibbard, p.l. (2007): middle pleistocene cold stage climates in the mediterranean: new evidence from the glacial record.– earth and planetary science letters, 253, 50–56. hughes, p.d. (2008): response of a montenegro glacier to extreme summer heatwaves in 2003 and 2007.– geografi ska annaler, 192, 259–267. hughes, p.d. & woodward, j.c. (2008): timing of glaciation in the mediterranean mountains during the last cold stage.– journal of quaternary science, 23, 575–588. kirigin, b. (1967): klimatske karakteristike sjevernog velebita [climate characteristics of the northern velebit mountain – in croatian].– zbornik radova x kongresa klimatologa jugoslavije, kopaonik 1967, beograd, 189–206. klein, a.-m. (1953): die niederschlage in europa im maximum der letzten eiszeit.– peterm. geogr. mitt., 97, stuttgart, 165−189. kotarba, a, hercman, h. & dramis, f. (2001): on the age of campo imperatore glaciations, gran sasso massif, central italy.– geografi a fisica e dinamica quaternaria, 24, 65–69. makjanić, b. (1978): bura, jugo i etezija [bora, scirocco and etesian wind – in croatian]. prilozi poznavanju vremena i klime sfrj, 5, savezni hidrometeorološki zavod, beograd, 1−43. geologia croatica 63/3geologia croatica 282 malinar, h. (1984): geneza jame puhaljke na velebitu [genesis of the puhaljka pit on velebit mountain – in croatian].– in: zbornik predavanja. deveti jugoslavenski speleološki kongres, karlovac 1984, 251–260. marjanac, lj. & marjanac, t. (2004): glacial history of the croatian adriatic and coastal dinarides.– in: ehlers, j. & gibbard, pl. (eds): quaternary glaciations – extent and chronology. part i: europe. amsterdam, elsevier, 19−26. nikler, l. (1973): novi prilog poznavanju oledbe velebita [a new contribution to knowledge of velebit mountain glaciation – in croatian].– geol. vjesnik, 25, 109–112. ogrin, m., sinjur, i. & ogrin, d. (2006): minimalne temperature v slovenskih mraziščih pozimi 2005/2006.– geografski obzornik, 53/2, 4–12. penzar, b. & penzar, i. (1995): velebit-klimatska prekretnica [velebit mountain – a climate turning-point – in croatian].– in: tvrtković, n. (ed.): paklenički zbornik 1, simpozij povodom 45. godišnjice np “paklenica”, starigrad-paklenica, 11–15. perica, d. & orešić, d. (1997): prilog poznavanju klimatskih obilježja velebita [the contribution to knowledge of climate characteristics of velebit mountain – in croatian].– acta geographica cro atica, 32, 45–68. perica, d., lozić, s. & mrak, i. (2002): periglacijalni reljef na području velebita [periglacial relief on the velebit mountain area – in croatian].– geoadria, 7/1, 5–29. poljak, j. (1947): o zaleđenju velebita [about velebit mountain glaciation – in croatian].– geol. vjesnik, 1, 125–148. poser, h. (1947): austauftiefe und frostzerrung in boden mitteleuropas wahrend der würmeiszeit.− die naturwissenschaften, 34/8, 232−238. riđanović, j. (1963): orjen, prilog poznavanju reljefa primorskih krških planina [orjen mountain, the contribution to knowledge of the relief of coastal karst mountains – in croatian].– doktorska disertacija, geografski odsjek pmf-a, zagreb, 193 p. rogić, v. (1958): velebitska primorska padina [the velebit mountain coastal slope – in croatian].– radovi geografskog instituta u zagrebu, 2, 1–114. šegota, t. (1963): geografske osnove glacijacija [the geographic fundamentals of glaciations – in croatian].– radovi geografskog instituta, 4, 1–119. šegota, t. (1982): razina mora i vertikalno gibanje dna jadranskog mora od ris-virmskog interglacijala do danas [sea level and vertical movement of the adriatic sea bottom from riss – würm interglacial until today – in croatian].– geol. vjesnik, 35, 93–109. šegota, t. & filipčić, a. (1996): klimatologija za geografe [climatology for geographers − in croatian].– školska knjiga, iii prerađeno izdanje, zagreb, 471 p. šegula, p. (1986): sneg led plazovi [snow ice avalanche – in slovenian].– planinska zveza slovenije, ljub ljana, 301 p. viera, g.t., mora, c. & ramos, m. (2003): ground temperature regimes and geomorphological implications in a mediterranean mountain (serra da estrela, portugal).– geomorphology, 52, 57–72. manuscript received july 23, 2009 revised manuscript accepted june 25, 2010 available online november 11, 2010 gc_2-2013_kb.indd  geologia croatica 66/2 153–154 1 fig. zagreb 2013 geologia croaticageologia croatica a response to the comment of roller-lutz et al. on the paper by lukač reberski et al. published in geologia croatica 66/1, 39–53 (2013): "defi nition of the river gacka springs subcatchment areas on the basis of hydrogeological parameters"  jasmina lukač reberski1, tamara marković1 and zoran nakić2 1 croatian geological survey, sachsova 2, zagreb, croatia 2 university of zagreb, faculty of mining, geology and petroleum engineering, pierottieva 6, 10 000 zagreb, croatia doi: 10.4154/gc.2013.13 as the authors of the above-mentioned paper in geologia croatica, issue 66/1, we felt the need to respond to the comment made by zvjezdana roller-lutz, tamara hunjak and hans o. lutz. we would like to refer to the claims: a) that we took isotope data (d and 18o) of springs for the year 2008 without consent, b) that isotope results were preliminary and shown only in an unpublished and not citable report, and c) that lmwl on fi g. 7 is plotted incorrectly. ad a): in the paper lukač reberski et al. (2013), isotopic data are presented for the period from 2002 till 2008. the isotope analyses of spring waters from 2002 till 2006 are the result of investigations carried out for the master thesis of jasmina lukač reberski (2008) which was a part of the project “basic hydrogeological map of the republic of croatia 1:100 000” funded by the croatian ministry of science, education and sports (project number 181-18110963165), and cro/8/006 project funded by iaea-tc (international atomic energy agency – technical cooperation) coordinated by the ruđer bošković institute (report is available at: http://bib.irb.hr/prikazi-rad?&rad=312123). the isotope analyses of spring waters for the year 2008 are the result of a cooperation project iaea-tc cro/8/007 coordinated by the university of rijeka, faculty of medicine, in which the croatian geological survey (cgs) also participated in a manner that researchers of the cgs performed fi eld work (water sampling, discharge measurements and measurements of in situ physico-chemical parameters). they also measured water chemical parameters in their laboratory. based on the verbal agreement between researchers of the project cro/8/007, the preliminary isotope data of spring waters (only for the year 2008) were given to researchers from the cgs, for the purpose of writing the phd thesis (lukač reberski, 2011). since phd theses are available to the public, any data contained therein cannot be considered confi dential. ad b): the aim of the paper by lukač reberski et al. (2013) was to present the overview of the phd thesis (lukač reberski, 2011) and new insights about the river gacka springs catchment area. furthermore, the university of rijeka asked the researchers from the cgs to cite the published paper (mandić et al., 2008) where the preliminary data were analysed. the mentioned paper was cited in the phd thesis (lukač reberski, 2011) and also in the paper: lukač reberski et al. (2013). that is the reason why the stable isotope data were included in the paper, although it had minor infl uence to the conclusions. ad c) an unintentional error occurred in figure 7 during the diagram construction due to which the graphical line that represents lmwl slightly moved from its original position. here is corrected fi gure 7. however, the explanation for figure 7 is cited from the paper mandić et al., 2008. geologia croatica 66/2geologia croatica 154 references horvatinčić, n., roller-lutz, z., kapelj, s. (2007): application of isotope techniques in investigation of water resources and water protection in the karst area of croatia (iaea tc cro/8/006) (fi nal report). lukač reberski, j, marković, t., nakić, z. (2013) defi nition of the river gacka springs subcatchment areas on the basis of hydrogeological parameters.– geologica croatica, 66/1, 39-53. lukač reberski, j. (2011) određivanje podsljevova izvorišta rijeke gacke na osnovi hidrogeoloških parametara [defi nition of the river gacka springs subcatchment areas on the basis of hydrogeological parametars – in croatian].– doctoral thesis. rudarsko geološko naftni fakultet, sveučilište u zagrebu (faculty of mining, geology and petroleum engineering, university of zagreb), 158 p. lukač reberski, j. (2008): hidrogeološka i hidrogeokemijska osnova za defi niranje slijeva gacke i zaštita njenog izvorišta [hydrogeological and hydrogeochemical basis for the catchment area defi nition: gacka river springs catchment area – in croatian].– master’s thesis. rudarsko-geološko-naftni fakultet, sveučilište u zagrebu (faculty of mining, geology and petroleum engineering, university of zagreb), 118 p. mandić, m., bojić, d., roller-lutz, z., lutz, h. & bronić krajcar, i. (2008): note on the spring region of gacka river (croatia).– isotop. envir. health studies, 44/2, 201–208. doi: 10.1080/10256010802066364. available online april 19, 2013 figure 7: the ratio of oxygen -18 and deuterium stable isotopes in spring waters of the gacka catchment. geologia croatica 45 69-86 6 fig. 5 pl. zagreb 1992 udc 551.35:551.763 (497.13) scientific paper the b~ttom current. s.ed.lql.~.qts .fc.o.n.tojjf.)tes) in the upper cretaceus deep-water deposits in.the northe~s·t.ern part of žumberak (croatia) ervin mrinjek key words: .contourit~s. contour s~quences, b9ttom currents, turbidites, hemipelagites, deep-water deposits, upper cretaceous, žumberak, dinarides. the upper cretaceous deep marine de~ its in ne ~art of žqmberak contain sedi ments deposited by bottom cilrient's ' j\1\lddy ,sandy and sandy-gravelly contourites•. the oomplete (nc;&lllive-posllive) seqdences and incomplete (negative-positive) sequences have been observoed. apart from the sediments that have been deposited bybott<im currents, severalturbidite layers reworked by bottom cutrents occur. l. introduction the upper cretaceous sediments in žumberak: belong to the zone of deep-water clastic layers placed on the north­ east side of the wide shelf carbonate belt spreading from tolmin through žumberak: and kordun to banja luka and further towards southeast (blanchet et al., 1970; aubouin et al., 1972; charvet, 1972; caron & cousin, 1973; babić, 1973, 1974; babić & zupanić, 1976). the clastic sediments are mostly composed of turbidites, hemipelagites and so far insufficiently exam­ ined sedim en ts which are the subject of this paper. these sediments are here attributed to bottom currents but some of them represent turbidites and hemipelagites reworked by bottom currents. although recent bottom currents have been revealed in submarine canyons and channels, their movements mainly follow slope isobaths or con tour lines. the terms contour currents and contourites are there­ fore used for such kind of currents and their deposits, but, very often, also for the bottom currents and their depos­ its the movements of which did not necessarily occur along the slope. this paper deals with a detailed description of sediment characteristics originated by bottom currents, their origin and their possible palaeogeographic situation. 2. situ a tion, stra ti graphic set­ ting and general characteristics of sediments the investigated outcrops are located in the north east part of žumberak in the nearby village novo selo, right at the foot of local road bregana kostanjevac and belong to .he layers characterized by alteration of micrites and/or marly miciites with detrital components ključne riječ.i: konturiti,konturitne sekvencije, turbiditi, hemipelagiti, pridnene struje, dubokomorski talozi, gornja kreda,žumberak, dinaridi. u dubokovodnim sedimentima gornje krede u sjeveroistočnom žumberku ustan~vljene su naslage pridnenih strujamuljni, pješčani i pjelčanolljunčani kontu riti•. kod većeg dijela konturnih naslaga prepoznate su potpune (negativno pozitivne) sekvencije. osim naslaga nastalih taloženjem iz pridnenih struja, izdvojeni su i talozi nastali prerađivanjem turbiditnih sekvencija. (mostly arenites and siltites) (fig.l). the layers are very close to lithologically similar outcrop which albian cenomanian age has been established by pelagic fora­ minifers (babić, 1974). the work was concentrated on three very close out­ crops with total thickness of about 20 m (fig. 2; pl. l, fig. l and 2; pl. ii, fig. 1). columns b and c have been disturbed by slumping. because ofvegetation cover, the outcrops are mutually isolated so that a complete recon­ struction of slum ping is impossible. the folded blocks are at a metre scale and are separated by slide surfaces from relatively undisturbed beds in columns. layers in column b (fig. 2; pl. i, fig. l) are reversed and might be a part of an overtumed fold or a detached block. the ihvestigated layers belong to the deep-sea faci es and for :he most part consist of contourite sequences with only rare beds which represent fine-grained turbidite sequen­ ces and/or hemipelagic intervals (mrinjek, 1988 a). 3. contourites muddy, sandy and sandy gravelly contourites could be differentiated according to structures and textures (primarily grain size). contourites display a peculiar regularity in vertical arrangement. their mutual boundaries might be gradual, sharp and flat or irregu­ larly erosional. 3.1. muddy contourites muddy -contourites are the most common type of cof!tourites. they cover nearly 60 % of the investigated succession. their thickness varies between 3 and 22 cm. their mutual contacts and contacts with hemipelagites department of geology and paleontology, faculty of sciences, 41000 zagreb, zvonimirova 8 70 fig. l. situation map. slika l. smjejtajna karta. are mostly gradual whereas the boundaries are sharp and flat or irregularly erosional (fig. 3, 4 and 5). muddy contourites are composed of micrites with a variable admixture of clay. silt-sized grains occur in thin laminae and minute lenses (inside contour beds) closely packed .with micrites matrix (packstone) or more, infrequently (fig. 3, 4 and 5) with sparite cement (grainstone) (pl. iv, fig. 2). the grains are mostly carbonate skeletal fnigments of globotruncanids, echinoderms, bi valves, . gastropods, and more or less, the particles of quartz, muscovite, feldspars, chlorites, clay minerals and opaque minerals. the grains of the same composition and size are dispersed inside micrite. on the basis of clay por. 'tion, mliddy contourites with less clay (calcilutites or .micrites) can be distinguished from those with more . clay (marly calcilutites or marly micrites). · .the main sedimentary structure characteristics are horizontallaminae composed of fine to very fine arenites, geologia croatica 45 siltites and micrites. the average thickness oflaminae ranges from 5 mm to 0,5 mm tilt in some con tour beds laminae up to 10 mm of thickness were ascertained. apart from horizontal laminae, regular lenticular, discontinuous and indistinct laminae can be seen. the lenticular laminae have sharp .and flat or irregularly erosional base. the to ps of lam!!lae are also sharp, and more or less flat and gradually change into massive micrites or marly micrites. long axes of elongated grains are mostly parallel to the stratification but are slightly imbricated in the inner parts of some laminae. a weak, normal grading, and a very seldom inverse grading can be seen within laminae (pl. ii, fig. 2; pl. iii, fig. l ) . indistinct and discontinuous laminae are commonly very thin (from 0,1 up to 0,2 mm) and composed of fine s i! t and micrite with the gradual bases and taps. some laminae have an irregularly convolute form ("wispy laminae"). their interruption and disturbance have been caused mrinjek : the bottom cu rent... 71 350m 19 )/ 1 ~ 8 -~ 12 . ' ( 13 !·:;.::.<;:,· -::~ 7 = 2 14 cm 8 <=> 3 c=:j "'--15 e. 20 ijjiiii) 9 ~ 18 cg '\ 4 10 -17 t•1 · •:r• te1·e, 5 lg.•šj 11 -...r18 h 21 • ••a fig. 2. position of columns and a legend for figs. 3-, 4 and s : l -granules and coarse arenites; 2-medium arenites and siltites; 3-micrites; 4-marly micrites; s-chert lenses and lenticular bedding cherts; 6-lenticular and irregular burrows; ?-regular lamination; s-lenses and lenticular lamination; 9-irregularly lenticular laminuion; 10indistinct and discontinuous lamination; 11-erosion and load structures; 12-sharp transition; 13-gradual transition; 14-muddy countourites; l s-sandy countourites; 16-sandy-gravelly countorites; 17 -fine-grained turbidites; 18-hcmipelagites; 19-cornplete (negative-positive) sequences; 20-incomplete (negative) sequences and incomplete(positive) sequences; 21-polished sample, acetale peel, thin section. slika 2. položaj stupova i legenda za sl. 3, 4 i s: l -granule i krupni arenili; 2-srednjezmati arenili i siltiti; 3-mikriti; 4-laporovili mikriti; s-leće i lečasti proslojci rožnjaka; 6-lečasti i nepravilni tragovi bubča; 7 -pravilne l amine; 8-leće i leća s ta laminacija; 9-nepravilno leća s ta laminacija; l o-nejasna i isprekidana laminacija; ]]. erozija i tragovi utiskivanja; 12-oštarprijelaz; 13-postepeni prijelaz; 14-muljni konturiti; is-pješčani konturiti; 16-pješčano-fljunčani konturiti; 17 -sekvencije sitnozmatih turbidita; 18-hcmipelagiti; 19-potpune (negativno-pozitivne) sekvencije; 20-nepotpune (negativne) sekvencije i nepotpune (pozitivne) sekvencije; 21-nabrusak, acetatna folija,izbrusak. by dewatering processes or bioturbation (pl. ii, fig. 2 and pl. iii, fig. 1). isolated lenses composed of siltites and fine arenites are relatively frequent. because of their shape and grain imbrication, some lenses could represent isolated and asymmetric ripples ("fading ripples") . relatively long and thin climbing ripples with very gently climbing angle have been observed at a few places (pl. ii, fig. 2 and pl. iii, fig. 1). regular and lenticular laminae as well as isolated ripples composed of fine arenites and siltites are usu­ ally randomly placed between and above discontinuous and indistinct silt and micrite laminae. however, con­ centrations and frequency of the laminae are a characteristic feature of the middle and the upper part of beds. one of the most typical features of numerous contourites is their extensive bioturbation which has modified or destroyed much of the primary sedimen­ tary structures, partially or completely altered the nature of the contacts and is probably responsible for the mixing of arenite, silt and mud together with fe-oxide mottles.oxides occur in baggy or pocket-like form at a millimetre and centimetre scale. this suggest that bioturbation was a continuous process, probably with several superimposed episodes (fig. 3, 4 and 5; pl. ii, fig. 2; pl. iii, fig. 1). certain more regular or inter­ nally structured forms are also recognized and can tentatively be identified as specific trace fossils. they include the small (up to 2 mm) elongated lenses and tubes sporadically densely spaced, which probably present a form of chondrites, more regular oval and ellipsoid forms that are mostly similar to p lanolites or traces with chevron structure like scolicia. 3.2. sandy and sandy-gravell y contourites sandy contourites are less common than the muddy ones. they are represented by less than 10 % in the whole succession and appear like irre gular beds from l to 17 cm of thickness, (most frequently between 4 and 6 cm). their lower boundaries are sharp or even erosional, with load deformations. sandy contourites as a rule are embedded in muddy contourites (fig. 3, 4 and 5). in the most cases, they do not display any internal order except for a slightly inverse or normal grading. how­ ever, sometimes a gen tle coarsening can be seen in their middle part. elongated grains are parallel in relation to the stratification but sometimes a weak imbrication can be also remarked. sandy contourites are composed of very coarse and coarse areni te sized grains and, more rarely, of fine sand72 o e o o a1 fig. 3. columns a l and a2. slika 3. stupovi al i a2. h geologia croatica 45 ej • cm ++ 5i• 4j•+ ic cm cm cm h ... mrinjek : the bottom cu rent ... 50 e () o b fig. 4. column b slika 4. stup b. . h? cm? cm h? h h? cm ~ h ---cm h 41-jo 73 13bl •• cm 13al•jo t 12bl• e1-e2 ___ 12•1. cm h 11ci • cm 8di i 22lc aci 8bl•+io sal lo te1-e3 1 21 o h l_ te1-e2 201• 7 i••io •• t ... . te1-e3 19jc • • fm a 74 platetabla i geologia croatica 45 plate· tabla i l. alternation of thinly bedded calcilutites and marly calcilutites. column b (fig. 2 and 4). izmjena tanko uslojenih kalklutita i laporovitih kalklutita. slijed b (sl. 2 i 4). 2. alternation of thinly bedded calcarenites with calcilutites and mar!.y calcilut'ites. column cl (fi g. 2 and 5). izmjena tanko uslojenih kalkarenita s kalklutitima i laporovitim kalklutitima. slijed cl (sl 2 i 5 ). mrinjek : the bouom curenl... plate tabla ii 75 plate· tabla ii l. thinly bedded calcarenites with chert lenses. layers have been folded by slumping. column cl (fig. 2 and 5) tanko uslo jeni kalkareniti s lećama rožnjaka. naslage su u formi polegle bore nastale klizanjem rotacijskog tipa. slijed cl {sl. 2 i 5). 2. muddy contourites, negative-positive sequence throughout the photo. calcilutite (wackestone) with thin and indistinct laminae. laminae composed of siltites and fine arenites are in the middle part of sequence (ar­ row). thinly lenticular jamina of microquartz {black) can be scen between laminae. the sediment has been disrupted by numerous lenticular burrows filled with marlaceous micrites {light-grey). column b. sample 8 d. acetate peel; x 2,5. muljni konturit, negativno-pozitivna sekvencija prisutna kroz cijelu fotografiju. donji i gornji dio sekvencije je kalklutit (wackestone) s tankim i nejasnim laminama silta. u sredini sekvencije su nepravilno lećast.e i utiskivanjem poremećene tamine silta i finog arenita (strelica). između lamina nazire se tanka jamina mikrokvarca (crno). sediment je poremećen brojnim lećastim tragovima bušača ispunjenih laporovitim mikritom (svijetlosivo). slijed b. uzorak 8 d. acetatna folija; x 2,5. 76 sized grains. the grains are mostly well sorted, rounded, weakly to moderately spherical, grain supported with point contacts and, more rarely, planar, interpenetrat­ ing or stylolitic contacts. as in the case of muddy contourites, the grains are mostly fragments of micrites and recrystallized micrite. some of fragments are partly clayey. sparitic fragments and the fragments of pelagic foraminifers, bi valves and echinoderms have been rarely found. they are more or less micritized. siliciclastic grains are rare. quartz is much more usual than feldspar fragments. numer­ ous quartz grains have corroded rims. on the other hand, some are fragments of composite quartz. rare pigments and mottl es of authigenic hematite occur; the same goes for opaque mineral grains. the grains are bound together by a drusy sparite or a microsparite or/and by micrite, while syntaxial rim cement is often seen on the echinoderm fragments. rare poikilotopic cement and dispersed silt-sized quartz and hematite grains, inside the sporadically recrystallized micrite, can be remarked. the only noticed sandy-gravelly contourite in the entire succession is placed in the middle part of col­ umn cl in between sandy contourites, and is composed of multiple alteration of coarse arenite-sized grain in­ tervals (4-7 mm thick) and fine arenite-sized grain intervals (about lo mm thick). a few rudite-sized and weakly rounded fragments (2-7 mm) of micrite, marly micrite or skeletons are found in coarse arenite inter­ vals with parallel or slightly inclined position of their longer axis in regard to the stratification. transitions between intervals are very gradual and sporadically very indistinct. rare rodite-sized fragments may be also remarked inside fine arenite intervals. unfortunately, its lower and upper boundaries are masked by extengeologia croatica 45 sive chert lenses (fig. 5; pl. v, fig. l and 2 ). except for poorly sorting, other grain characteristics like grain type, grain portion are nearly the same as they are in sandy and muddy contourites (pl. v, fi g. l and 2 ). the gr ai ns are bounded together by the drusy sparite and also, but more infrequently, by poikilotopic cement. fibrous calcite cement may be seen around some fragments. dark-grey and dark-red nodular and lenticular chert, 0,5 to 6 cm thick, is a frequent diagenetic feature of sandy contourites. silicification has usually taken place in the middle part of beds. the very rare chert lenses and nodules inside muddy contourites, mostly at a millimetre scale, have been originated by complete or partial silicification of si lt and fine arenite jaminae and lenses (fig. 3 and 5, pl. ii, fig. 2; pl. iv, fig. l and 2 ). chert is composite of a microquartz with the dispersed rests of brownish s pari te inside. both chert and the s par particles are contaminated by fe-oxides. 4. contourite sequences the contourite sequences have a regular vertical ar­ rangement although not so clearly developed as it is within fine-grained turbidites. a distinctive feature of a contourite packet is a presence of n e g a 1 i v e s e q u e n e e s in which the number and size of lam i nae and the size of grains increase upwards and of p o s i 1 i v e s e q u e n e e s in which these characteristics decrease upwards (stow et al., 1984). both sequences are often joined together into one n e g a 1 i v e -p o s i 1 i v e s e q u e n e e or, in other words, in one e o m p l e l e s e q u e n e e , but in this case the symmetry is not always present. nega­ tive or positive parts can be more or less expressed or can be thinner or thicker. there is sometimes a problem in distinguishing positive sequences from fine-grained turbidite sequences. negative scquences have gradual and plate tabla iii l . muddy contourite, negative-positive sequence. the lower part of sequence is marlaceous micrite. horizontal and irregularly lenticular laminae composed of calcilutites and very fine calcarenites are in the middle part of sequence (arrows). the laminae are sporadically disturbed by burrows. numerous burrows and laminae composed of calcilutites may be seen in the upper part. the upper part is marlaceous micrite. in the lower, weakly reverse graded part there can be a normal grading. column b.sample 8 b. acetate peel; x 2. muljni konturit, negativno-pozitivna sekvencija. donji dio je laporoviti mikrit u središnjem dijelu vide se horizontalne i nepravilno lećaste lamine kalksiltita i vrlo finog kalkarenita (strelice), mjestimice poremećene bušačima. u gornjem dijelu, također izgrađenom od laporovitog mikrita, naziru se tamine kalksiltita i prisutni su brojni tragovi bušača. gornji dio je jedva primjetno graduiran za razliku od donjeg dijela koji je slabo inverzno gradu iran. slijed b. uzorak 8 b. acetatna folija; x 2,2. 2. fine-grained turbidite sequence (te1-e1-ej. the lower part is marly micrite disturbed by multi-stage bioturbation (muddy contourite). the middle part begins with lenticular and deformed jamina composed of fine sand and silt (interval e1) and is succeded by alternation of irregularly lenticular, regular and indistinct jaminae also composed of fine arenite and siltite (interval ej. the upper part is calcilutite (wackestone) with many lenticular and irregular burrows (interval ej. column b. sample 6 a. acetate peel; x 2,2. sekvencija sitnozrnatog turbidita (te1-e1-ej. donji dio je laporoviti mikrit (muljni konturit) poremećen višestrukom bioturbacijom. središnji dio (interval e1) počinje lećastom i djelomično deformiranom laminom finog arenita i silta. slijedi višestruka izmjena nepravilno lećastih, pravilnih i nejasnih jamina silta i finog arenita i nejasna normalna graduiranost (interval e1). gornji dio je kalklutit (wackestone) s brojnim lećastim i nepravilnim tragovima bušača (interval e3). slijed b. uzorak 6 a. acetatna folija; x 2,2. mrinjek : the bottom curent... platetabla iii 77 78 geologia croatica 45 h l 1±-!:tl-8± ~ -·-=--a;z;a cm o h __ ea č.:.:. .t :.:...; ~--::::~~~ t-[l so 3 i•., i a l<z>o ~:~ lj f-' '-l ....l ~ cg + --ea e ca ....:: u ... tj ~:....._~11• h?ca ~u '·.•.>7•i' h?j ca h _l r tit .. · · ·~ o . "' fi~. 5. columns c and e . shka 5. stupovi c l c 2 l 2. mrinjek : the bottom curent ... lithology mean and grain size structure 50 e cj 4 8 16 32 64,um -.q.t -_q···=--o:.. eo•._ ---------------\ ( \\ ~~ ej silt and sand ~ mud ~ shell fragments ~&b ~ bioturbation maximum velocity ~ d iscontinuous si lt lenses gradational contact -vsharp ( irregular} contact fig. 6. ideal complete (negative-positive) contourite sequence (from stow & piper, 1984). slika 6. idealna potpuna (negativno-pozitivna) konturitna sekvencija (iz stow & piper, 1984). faintly visible beginning from hemipelagites whereas their to ps are sharp and clear, flat or slightly wavy. of course, the opposite is in the case of positive contourite sequences (fig. 3, 4, 5 and 6; pl. iii, fig. l; pl. iv, fig. 2). sandy contourites are commonly placed between muddy ones in the middle part of negative-positive sequences, but some of them are at the beginning of positive sequences or on the top of negative sequences. sandy intervals can have a gen tle reverse or a normal grading, o.r even a gently co.arseni.ngjq tp~ir middle · part (fig. 3; 4, 5 and 6:· pl. iv; fig. 1). n~ thiclcness of sequences varies from 5 up to 30 cm. 79 5. fine-grained turbidites the fine-grained twbidites are oni y present in the "column b, and represent about 10% of all investigated successions. an ideal fine-grained turbidity sequence consists of three parts denoted by piper's signs e 1 , e 2 and e 3 (piper, 1978). the complete sequences (te1-e3) and top-cut-out se­ quences (te 1 -e 2 ) are approximately represented in similar amount the mutual bmmdaries, and the lx;>\mdaries between turbidites and the contourite sequences are usually sharp, even load-casted and erosional in some cases. the upper contact with hemipelagites is transitional instead. as in the case ofmuddy contourites, calcilutite sequences with less amount of clay and calcareous mari sequences with bigger amount of clay can be distinguished (fig. 4; pl.iii, fig. 2). i n t er v a l "e 1 " contains the same laminae and lens types as the muddy contouritesregular, irregular, lenticular, indistinct and wispy laminae of siltites and fine arenites. the internal frame of laminae and lenses and their grain kind and frequency are the same or nearly the same as with muddy contourites. the main distinction between them is in a vertical arrangement of type, size and number of laminae and lenses. namely, their number and thick­ ness gradually decrease towards the top of interval "e 1 ". isolated and asymmetrical ("fading") ripples and long, thin climbing ripples are located in the lower part or even at the beginning of interval whereas indistinct, discontinuous and "wispy" laminae are placed as a rule in the upper parts of interval. biotwbation is weaker than in other intervals (fig. 4; pl. iii, fig. 2). i n t e rv a l "e2" is characterized by the gradually upwards decreasing amounts and size of silt-sized grains and fine arenite-sized grains. besides the grading, there are numerous burrow traces (fig. 4; pl. iii, fig. 2). i n t er v a l "e3" is massive. there are only sparse silt-sized and fine arenite-sized grains. this part is also disturbed by vigorous bioturbation. transitions between intervals are gradual and therefore hardly noticeable (fig. 4; pl. iii, fig. 2 ). 6. hemipelagic inter v als the hemipelagites are thin bedded, usually between l and 13 cm, and massive. they are composed of micrites and of greater amount of clay with rare and irregularly dispersed silt and fine arenite-sized grains of sparite, quartz, muskovite and feldspar. they have more vig­ orous bioturbation than muddy contourites and fine grain ed turbidites. hemipelagic deposits represent about 18 % of the investigated succession. they are found on the top of fine-grained turbidites or between muddy and sandy contourites. their boundary with muddy contourites is gradual , whereas the upper boundary between them and sandy contourites or fine-grained turbidites is usually irregular and erosional (fig. 3, 4 and 5; pl. iii, fig. 2). 7 .•. processes bottom currents have an important effect on nature and distribution of bottom sedi ments. they result from so circulation caused by density differences between masses; their speed being in close relation with changes of climatic and oceanographic factors. long-term current mea­ surements show that bottom currents vary greatly in time and space, having tidal, seasonal and irregular periodicity and reversal s (stow et al. ,1984 ). v as t areas of the oceans have been observed where currents are weak or negligible as well as areas where current ve­ locity can reach over 100 cm/s for a short period of time. bottom currents are capable of eroding, transporting and depositing sediments up to about medium sand sized grains, of reworking coarse-grained sands and winnowing finer material away from coarser-grained sandy and gravelly sediments (stow et al.,l984). bottom cur­ rents transport also fine material in suspension ( average size about 0,012 mm) in thin to thick (even over 1500 m), very low concentration (0,01 to 0,3 mg/l) nepheloid layers, in some cases over thousands of kilometres (stow et al., 1984). suspended sediments enter the nepheloid layec from below by bottom current erosion, sediment resuspension due to burrowing organisms, internal waves, the fine tails of turbidity currents, and from vertical settling of hemipelagic and pelagic material through the wa­ ter column. so in many cases the depositional process must be considered intermediate between bottom cur­ rent, turbidity current, pelagic and hemipelagic. the vertical variation in the described contourite sequences is probably related to variation in velocity of the transporting current rather than to variation in supply. thus complete (negativepositive) sequences represent a gradual increase, a maximum and then grafl•:al decrease in current velocity. such fluctuations could be slow and progressive as shown by the thicker se­ quences or more rapid and sudden, as shown by thinner ones. the increase, however, in the current velocity could be gradual and decrease could be abrupt and rapid (incomplete, negative sequences), or gradual (incom­ plete, positive sequences). horizontal and lenticular silty laminae and thin climbing ripples are related to maximum current vegeologia croatica 45 locity. since indistinct and discontinuous lam i nae and massive micrite can be seen between them, it is possible that, during maximum velocity periods, very short-time velocity fluctuations have existed. rare sandy contourites represent intervals of very strong bottom currents capable of transporting and depositing medium and even coarse sand-sized grains, although some of them might even represent reworked turbiditic sands. the multiple and irregular alternation of erosion and/ or winnowing finer material away from turbiditic sands and gravels with deposition ofc oarse sands and fill­ ing of grain interstices with fine sands, have been probably needed for creating sandy-gravelly contourite. depositional sorting and flocculation are probably the main origin of laminae with a gradual decrease of their thickness and number in the fine-grained turbid­ ity sequences (stow & bowen, 1980). according to the authors, the alternation of silt and micrite laminae has been created by depositional sorting which was caused by shear stress changes in the lower boundary layer of flow. at the beginning, mud floc­ culation and mud floc deposition have been made impossible because of shearing so that only fine areni te­ sized and silt-sized grains could be deposited through the viscous boundary layer. this created tractive ripples and laminae. by flow weakening and mud density increasing, the efficient flocculation and very fast deposition of a "muddy blanket" have been enabled through the lower, laminar boundary layer of flow on the earlier formed ripples "}ind lam i nae. this process :has been repeated several times with fi ner and fi ner sand and silt grains, and a greater amount of mud; thinner and subsequently indistinct laminae have been created in this way. at the end of the process, a negligible amount of si lt and fines t sand grains remained, so that al most only mud was deposited (intervals "e 2 " and "e 3 "). fluctuations in the current velocity or interference of the low-density turbidity current with a bottom current might have caused the presence of thicker laminae above platetabla iv l . the lowermost level is partly eroded marly micrite with indistinct lamination. the rest is very coarse sized and reverse graded arenite (sandy contourite). a great part of arenite is silicified (black). column a2. sample 3. acetate peel; x 1,6. najdonji dio je laporoviti mikrit s nejasnom laminacijom, svijetlosivo i djelomično erodiran vrlo krupnozrnastim i reversno graduiranim kalkarenitom (pješčani konturit), veliki dio kalkarenitaje zahvaćen silifikacijom (crno). slijed a2. uzorak 3. acetatna folija; x 1,6. 2. sandy contourite in the complete contour sequence. marly micrite with indistinct and interrupted laminae composed of siltites is in irregular sharp contact with a thick lens of fine-grained calcarenite. the lens is weakly reversely graded in the lowermost part. the upper part is a marly micrite with indistinct lamination and thinly lenticular burrows. transition from lens to upper micrite is gradual. column b. sample 8. acetate peel; x2,5. pješčani konturit unutar potpune konturne sekvencije. donji dio koji je izgrađen od laporovitog mikrita s nejasnim i isprekidanim laminama silta je u oštrom i nepravilnom kontaktu s proslojkom finog kalkarenita. proslojak je jedva primjetno inverzno graduiran u svom najdonjem dijelu. gornji dio je laporoviti mikrit sa nejasnom laminacijom i tankim lećastim bušotinama. prijelaz finoarenitnog proslojka u mikrit je postepen. slijed b. uzorak 8. acetatna folija; x 2,5. mrinjek : the bottom curent ... plate tabla iv 81 82 thinner or indistinct ones. flocculation was less effi­ cient in that case, because of greater amount of the carbonate grains with respect to the silicate grains. this is probably the reason why irregular and indistinct laminae are only present in some turbidity sequences. depositional sorting should be involved in the contourite origin because all possible transition between contourites, fine-grained turbidites and hemipelagites could be expected. fine-grained sediments are not so much character­ ized by the burrow varieties as they are by the intensity of bioturbation. hemipelagites are nearly always en­ tirely and multiply disturbed by burrows but, in most cases, laminae and other primary features are at least partly preserved whereas the traces of burrows are almost absent in sandy contourites. the most intensive bioturbation is also characteristic for higher parts of the fine-grained turbidite sequences. 8. palaeogeographic setting recent contourites are deposited on continental slopes, like well-laminated drifts spreading parallel with slope. they have been also noticcd in basin plains (stow & piper, 1984). fine-grained turbidites have been found in very diverse areas like slopes, subaqueous fans and on basin plains (stow & piper, 1984). columns cl and c2 contain sandy and sandy-gravely contourites which have been originated by reworking and winnowing of turbidite sequences, and they prnb­ ably belong to a slope or upper fan, relatively near a subaqueous canyon or channel mouth. synsedimentary slumping might point out this position (fig. 2 and 5). on the other hand, disturbed layers in column b have been probably deposited by sliding on a slope but relatively further away from channels (fig. 2 and 4). the layers in columns al and a2 are likely to belong to the lower part of slope or even to a basin plain. two petrographic types of lutites calcilutites and marly calcilutites could be a proof of different material sources geologia croatica 45 or respectively may point out different paleocurrent directions or changing in a clay share. 9. conclusions the contourites and sediments which have arisen from bottom currents, most probably contour currents, dominate in the upper cretaceous deep-water clastic zone in žumberak. muddy, sandy and sandy-gravely contourites can be differentiated according to structures and textures (primarily grain size). muddy contourites, as a dominating member of the investigated succession, are characterized by a mutual alternation of horizontal, len tic ular, indistinct and discontinuous fine arenite and siltlaminae inside more or less marly micrite and, also, by vigorous bioturbation, mostly trough all their thickness. sandy contourites which are considerably more infrequent in regard to muddy contourites, appear as thin and irregular beds with erosional undersurfaces. they are mostly composed of coarse areni te-sized grains that can be gently reverse or normally graded. only one sandy-gravelly contourite composed of multiple alteration of coarse arenite-sized grain inter­ vals and fine arenite-sized grain intervals could have been seen. . muddy contourites and a great part of sandy contourites have been transported and deposited by bottom currents. a lesser part of contourites could be re worked turbiditic sands, whereas sandy-gravely contourite might represent a manifold alternation or erosion and win­ nowing of turbiditic gravels and co~se arenites during very strong currents. in most contourites, one can see the vertical ar­ rangement of laminae and lens type and size and also average grain sizes, or complete sequences (negative­ positive) and incomplete sequences (negative or positive) ·respectively and whose origin is in the close relation to the current velocity. platetabla v 1. sandy-gravelly contourite. alteration of coarse calcarenite intervals with fine calcarenite ones. transitions are gradual and sporadically indistinct. rare, poorly rounded and imbricated rudite grain can be seen inside the fine areni te intervals. sample from the lower part of the sandy-gravelly contourite with initial silicification (black). column cl. sample 2. acetate peel; x 2,7. pješčano-šljunčani konturit..izmjena inte~al~ krupnog kalkareriita s intervalima finog kalkarenita. prijelazi između intervala su postepeni ili čak mjestimice nejasni. unutar intervala finog arenita mogu se zapaziti slabo zaobljeni ruditni fragmenti blago kosog (imbriciranog) položaja u odnosu na slojevitost. donji dio pješčanoššljunčanog kon turi ta čiji je početak zahvaćen silicifikacijom (crno). slijed cl. uzorak 2. acetatna folija; x 2,7. 2. sandy-gravelly contourite. alternation of coarse calcarenite intervals with fine calcarenite intervals. tran­ sitions are gradual and sporadically indistinct. rare, poorly rounded and imbricated rudite grains can be seen inside fine arenite intervals. the top of the sandy-gravelly contourite. column cl. sample 3. acetate peel;x 2,7. pješčano-šljunčani kon turi t. izmjena intervala krupnog kalkarenitaa s intervalima finog kalkarenita. prijelazi između intervala su postepeni ili čak mjestimice nejasni. unutar intervala finog arenita mogu se zapaziti rijetki, slabo zaobljeni ruditni fragmenti blago koso g (imbriciranog) položaja u odnosu na slojevitost. završni dio pješčano­ šljunčanog konturita. slijed cl. uzorak 3. acetatna folija; x 2,7. mrinjek : the bottom curent ... platetabla v 83 84 sandy and sandy-gravelly contourites probably belong to a slope or upper fan environment, relatively near a subaqueous canyon or channels, while muddy contourites have been deposited on a lower part of slope, relatively farther away from channels or even on a basin plain. 10. references aubouin, j., blanchet, r., cadet, j .p.,celef, p., charvet, j., cohorowicz, j., cousin, m. & rampnoux, j.p. (1972): essai sur la geologie des dinarides. bull. soc. geol. france, (7), 12/6, 1060-1095, paris. babić, lj. (1973): bazenski sedimenti gornjeg titona, beriasa i valendisa, zapadno od bregane.-geol. vjesnik, 26, 11-27, zagreb. babić, lj. (1974 ): razdoblje otriv-cenoman u žumberku: stratigrafija, postanak sedimenata i razvoj prostora. geol.vjesnik 27, 11-33, zagreb. babić, lj. & zupanič, j. (1976): sedi menti i paleo geografija zone globotruncana calcarata (gornja kreda) u baniji i kordunu (središnja hrvatska). geol. vjesnik, 29, 49-73, zagreb. bl.anchet,r,cadet,j. p .. charvef,j.&ramfnoux, jp.(l970): sur l' existence d'un important domaine de flysch tithonique cretace inferieur en yougoslavie: l'unitee du flysch bosniaque. -bull. soc.geol. france, (7), 11/6, 871-880, paris. caron, m. & cousin, m.(l973): le sillon slavene: les formations terrigenes cretacees des unite extertnes au nord-est de tolmin (slovenie occidentale). bull. soc. geol. france, (7),14/1-5, 34-35, paris. char vet, j .(1972): a per u geologique des dinarides aux environs du meridien de sarajevo. bull. soc. geol. france, (7), 12/6, 986-1002, paris. geologia croatica 45 gontider, e.g., faugeres, j.c.& stow, d.a.v. (1985): contourite facies of the fayro drift, gulf ofcadiz. -in: stow, d.a.v. &piper, d.j.w. (eds.): fine-grained sediment: deep-water processes and facies.blackwell, 275-292, oxford. mrinjek, e.(l988a): sitnozrnati turbiditi i konturiti u dubokovodnim sedim entima gornje krede kod slunja i u žumberku.geol. glasnik, pos. izd. vi, zbornik radova vi skup. sed. jug., 135-149, titograd. · mrinjek, e.(l988b): sitnozrnati turbiditi cenomana u prelaznom pojasu unutrašnjih i vanjskih dinarida sjeveroistočno od slunja. geol. vjesnik, 41, 181196, zagreb. piper, dj .w. (1978): turbidite muds and silts on deep sea fans and abyssal plains. -in: stanley, d. j. & kellin, g.(eds.):sedimentation in sub­ marine canyons, fans and trenches.dowdcn, hutchinson and ross, 163-176,stroudsburg. stow, d.a.v. & bowen, a.j.(i980): a physical model for transport and sorting of finegrained sediment by turbidity currents. sedimentology, 2 7 /l, 3146, oxford. stow,d.a.v. & holbrook, j.a. (1984): north atlantic contourites: an overview.in: stow, d.a.v. & piper, d.j.w. (eds.): fine-grained sediment: deep-water processes and facies. blackwell, 145-256, oxford. stow, d.a.v. & piper, d.j.w. (1984): deep-water fine-grained sediments: facies models. in: stow, d.a.v. & piper, d.j.w. (eds.): fine­ grained sediments: deep-water processes and facies. -blackwell, 611-646, oxford . sedimenti pridnenih struja (konturiti) u dubokovodnim naslagama gornje krede sjeveroistočnog žumberka e. mrinjek istraži vane naslage se nalaze u sjeveroistočnom dijelu žumberka i pripadaju roni gomjokrednih dubokomorskih taloga, smještenoj na sjeveroistočnoj strani prostranog karbonatnog šelfa (vanjski dinaridi, babić & zupanić, 1976). naslage karakterizira izmjena konturita te u mar joj mjeri sitnozrnatih turbidita i hemipelagita. mogu se razlikovati tri tipa konturita m u l j n i , p j e š č a n i i p j e š č a n o š l j u n č a n i konturiti (sl. 3, 4 i 5). muljni konturiti, čija debljina varira od 3 do 22 cm, su najčešći tip. međusobr~. granica između samih m uljnih kon turi ta i kon turi ta i hemipelagita je postepena, dok je kontakt s pješčanim konturitima i finozrnatim turbiditima oštar ili čak oštro nepravilan (sl. 3, 4 i 5). muljni kon turiti su izgrađeni od mikrita s promjenjivom količinom gline kao i od karbonatnih i siliciklastičnih čestica veličine finog arenita i silta. silikatne čestice su podređene u odnosu na karbonatne čestice. njihova glavna teksturna karakteristika je prisutnost pravilnih, nepravilnih, lećastih i nejasnih jamina silta i finog arenita. prosječna debljina laminaje od 0,5 do 5 mm iako lamines mogu biti između 0,1 do 0,2 mm tanke. osim normalno graduirane, tamine mogu biti inverzno ili normalno­ inverzno graduirane. prisutni su brojni tragovi bušača koji su poremetili ili prekinuli tamine {tab. ii, sl. 2; tab. iii, sl.l). pješčani konturiti su rjeđi od m uljnih konturita. dolaze kao nepravilni slojevi, debljine l do 17 cm, izgrađeni su od karbonatnih i siliciklastičnih čestica veličine krupnog arenita. njihova glavna karakteristika je blago inverzna ili normalna graduiranost, ili čak inverzno­ normalna graduiranost (sl. 2, 4 i 5;tab. l, 2 i 3). jedan jedini pješčanošljunčani konturit se nalazi u srednjem dijelu stupa cl i izgrađen je od višestruke mrinjek : the bottom curent ... izmjene intervala krupnog arenita debljine 4-7 mm i intervala finog arenita debljine oko lo mm. nekoliko rudi tnih fragmenata (veličine 2-7 mm) mikrita, glinovitog mikrita ili skeleta nalaze se unutar krupnog arenitnog intervala. prijelaz između intervala je vrlo postupan i mjestimično nejasan (sl. 5; tab.v, sl. l i 2 ). postoji u određenoj mjeri pravilna vertikalna uređenost unutar konturita. iako ne toliko jasna kao unutar finozrntih turbidita, pa se može govorti o n e g a t i v n i m s e­ k v e n e i j a m a u kojima broj i veličina jamina i veličina zrna rastu prema gore i o p o z i t i v n i m s e k v e n e i j a m a u kojim te karakteristike o padaju prema gore (stow et al., 1984). cesto puta su obje sekvencije pridružene zajedno u jednu n e g a t i v n op o z i t i v n u s e k v e n e i j u pri čemu simetrija ne mora biti uvijek prisutna, tj. negativni ili pozitivni dijelovi mogu biti jače ili slabije izraženi, odnosno deblji ili tanji (sl. 3, 4 i 5). pješčani konturiti su obično smješteni između muljnih konturita u središnjem dijelu negativno-pozitivne sekvencije. pješčani konturit (interval) je obično blago inverzno ili normalno graduiran ili samo blago pokrupnjuje u svom središnjem dijelu (sl. 3, 4 i 5; tab. iv, sl. l, 2 i 3). sitnozrnati turbiditi su prisutni samo u stupu b. istog su petrografskog sastava kao i konturiti ali za razliku od njih, njihove strukturne i tekstume karakteristike imaju prav ilni ji vertikalni raspored. njihova idealna sekvencija se sastoji od tri dijela označenih piperovim oznakama "e 1 ", "e 2 " i "e 3 " (piper, 1978). kompletne sekvencije (te 1 -e:j i odrezane sekvencije (te 1 -e 2 ) su približno podjednako zastupljene u istraživanom slijedu (sl. 4). njihova debljina je između 4 i 9 cm. njihove međusobne granice i granice između njih i konturita su obično oštre i erozivne ili čak poremećene utiskivanjem, dok je krovinski kontakt s hemipelagitom prijelazan. glavna karakteristika donjeg dijela sekvencije (interval "e 1 ")su pravilne, nepravilne, lećaste, nejasne i "wispy" tamine siltita i finog arenita. osim lam ina, interval "e 1 " sadrži i izolirane rip love i tanke "penjajuće" riplove. bioturbacijaje slabije izražena nego u ostalim intervalima (tab. iii, sl. 2). postepeno smanjivanje količine i veličine siltnih i finoarenitnih čestica je glavna karakteristika intervala "e 2 " . osim graduiranosti prisutni su brojni tragovi bušača (tab. iii, sl . 2). interval "e," je masivan sa samo rijetko raspršenim siltnim i finoarenitnim česticama. u pravilu je gotovo uvijek jako bioturbiran. prijelazi između intervala su postepeni i stoga teško primjetni (sl. 4; tab. iii, sl. 2). hemipelagiti su tanko uslojeni, obično između l i 13 cm tanki, masivni·, s više gline i jače izraženom bioturbacijom nego muljni konturiti i sitnozrnati turbiditi. nalaze se između m uljnih konturita, muljnih i pješčanih konturita ili su kontinuirani. pridnene struje imaju snažan utjecaj na distribuciju i sastav taloga dna d~jih oceana i mora. za razliku od površinskih i pri površinskih struja koje nastaju puhanjem vjetra uzrokovanog razlikama u gustoći, odnosno razlikama u pritisku zraka, pridnene struje nastaju termohalinom cirkulacijom uzrokovanom 85 razlikom u gustoći pojedinih dijelova mora, te je stoga njihova brzina u uskoj vezi s promjenama klimatskih i oceanografskih faktora. dugotrajna praćenja i mjerenja pridnenih struja otkrila su značajna dnevna, sezonska ili vremenski nepravilna variranja njihovih brzina kao i velike promjene njihovog smjera kretanja (stow et al., 1984). također su otkriveni veliki dijelovi morskih dna sa slabim ili beznačajnim djelovanjem struja, kao i dijelovi dna sa snažnim djelovanjem struja gdje u kratkim vremenskim intervalima brzina struje može biti veća od 100 cm/sek., tako da su sposobne erodirati, transportirati i deponirati taloge sa zrnima do veličine srednjeg pijeska, prerađivati krupni pijesak ili ispirati sitnozrnati materijal iz šljunka i vrlo krupnog pijeska (stow et al.,l984). utvrđeno je da pridnene struje prenose finozrnatu suspenziju prosječne veličine zrna od oko 0 ,012 mm u tankim do debelim (čak i preko 1500 m) nefeloidnim slojevima vrlo niske koncentracije (0,01 do 0,3 mg/l) tisućama kilometara daleko. suspendirani materijal potječe od taloga dna pokrenutog erozivnim djelovanjem pridnenih struja, a dio može potjecati i iz repa razrijeđene turbiditne struje kao i od pelagičkih i hemipelagičkih čestica zahvačenih pridnenim strujama. stoga takvo složeno porijeklo materijala nošenog pridnenim strujama može objasniti sve moguće prijelaze između konturita, sitnozrnatih turbidita i hemipelagita i/ili pelagita prepoznate i u istraživanim slijedovima. vertikalne varijacije konturnih facijesa uočene u istraživanim slijedovima prvenstveno su u vezi s promjenjivošću brzina pridnenih struja, dok je izvorište materijala moglo imati mali ili nikakav utjecaj. opisane negativnopozitivne sekvencije bi stoga predstavljale postepeni rast, maksimum i postepeni pad brzine struje. takve fluktuacije su mogle biti relativno spore, na što ukazuju deblje sekvencije, ili pak brze i nagle, na što ukazuju tanje sekvencije~orast brzine struje je mogao biti postepen, a slabljenje naglo (nepotpune negativne sekvencije) ili obrnuto,~tj. nagli porast brzine, a zatim postepeno slabljenje (nepotpune pozitivne sekvencije). horizontalne i lećaste lam ine finog arenita i silta kao i tanki penjući riplovi vezani su za period maksimalnih brzina struja. s obzirom da između njih postoji i prostor ispunjen nejasnim i isprekidanim laminama kao i mikritom, očito je da su unutar perioda maksimalnih struja postojale kratkotrajne sekundarne fluktuacije brzina na što ukazuju i neke lam ine s blago normalno ili blago reversno graduiranom građom. rijetki pješčani konturiti mogu predstavljati interval~ izrazito.snažnih pridnenih struja koje prenose i talože srednji ili čak krupni pjesak, ali isto tako neki od njih mogu predstavljati manje ili više in situ prerađivane krupne turbidne pijeske. snažna ali i vrlo promjenjiva pridnena struja je bila potrebna za stvaranje pješčana šljunčanog konturita kod čijeg je postanka vjerojatno postojalo višestruko i nepravilno izmjenjivanje procesa erozije i ispiranja turbidnog pijeska i šljunka s procesima taloženja krupnog pijeska i ispunjavanja međupornog prostora sitnim 86 pijeskom. taloženju siblozrnatih turbidita pripisivani su različiti načini (stow & piper, 1984) ali se čini da najprihva­ tljivije obj~njenje daju stow & bowen (1984). po njima je izmjena jamina silta nastala depozicijskim sortiranjem zbog promjene sila naprezanja u donjem graničnom sloju. u početku naprezanje ne dopušta flokulaciju i taloženje mulja nego se kroz viskozni dio graničnog sloja talože čestice finog arenita i krupnijeg silta koje vučenjem fonniraju riplove i lamine. slabljenjem toka i povećanjem koncentracije mulja omogućena je uspješna flokulacija i vrlo brzo taloženje "muljnog pokrivača" kroz najdonji laminirani dio toka na već prije formirane riplove i lam ine. taj proces se ponavlja više puta ali sa sve sitnijim česticama silta i sve većom količinom mulja, tako da depozicijskim sortiran jem dolazi do sve tanjih, a zatim i nejasnih lamina silta. nakon toga preostaje u toku neznabla količina silta i najfinijeg arenita pa se taloži mulj što odgovara srednjem i gornjem dijelu sekvencije (interval "e2" i "en. kod promjena kod kojih nisu uvijek vidljive, a niti . pravilno raspoređene karakteristike siblozmatih turbidita, moguće je da je došlo do miješanja djelovanja turbidne struje s pridnenom strujom ili pak do prevlasti djelovanja ove potonje. također treba naglasiti da u sastavu geologia croatica 45 istraživanih turbidnih sekvencija manje ili više prevla­ davaju karbonatne čestice što sigurno onemogućuje uspješnu flokulaciju i time depozicijsko sortiranje kako je bilo interpretirano analizom siliciklastičnih turbidita (stow & bowen, 1980) paje to moglo dovesti do razvoja nejasnih lamina i jedva primjetno g gradu iranja. s druge strane mehanizam depozicijskog sortiranja mogao je barem djelomično postojati i kod konturita na što upućuju i svi mogući prelazi između kon turi ta, sitnozmatih turbidita i hemipelagita. tipove siblozmatih naslaga ne karakteriziraju toliko posebni tipovi bušača koliko intenzitet bioturbacija. tako su hemipelagiti gotovo u pravilu potpuno višestruko bioturbirani različitim tipovima bušača. muljni konturiti su također bioturbirani kroz cijelu svoju debljinu ali su u većini slučajeva barem djelomično sačuvane lam ine i ostale karakteristike, dok kod pješčanih kon turi ta gotovo da tragova bušača nema. kod sitnozrnatih turbidita intenzivnija bioturbacija je vezana za gornje dijelove sekvencija. • pješčani i pješčano-šljunčani konturiti vjerojatno su taloženi na padini ili višim dijelovima lepeze, relativno blizu podmorskog kanjona ili kanala, dok su muljni konturiti taloženi na donjem dijelu padine ili lepeze, ili čak na đnu bazena. manuscript received march, 31. 1992. revised manuscript accepted july, 20. 1992. 15-novak-zelenika.indd 173 � ab stra ct the research presented herein is the fi rst attempt to perform geostatistical simulations on three geological variables, porosity, thickness, and depth to reservoir, in the croatian part of the pannonian basin. the data were collected from a reservoir of lower pontian age in the kloštar field, located in the western part of the sava depression. all three variables were analyzed using sequential gaussian simulations (sgs). information regarding present-day depth, thickness, and locations of areas with higher porosity values were used to reconstruct palaeo-depositional environments and the distribution of different lithotypes, ranging from medium-grained, to mostly clean sandstones and to pure, basin marls. estimates of present-day thickness and depth can help to defi ne areas of gross tectonic displacement and the role of major faults that have been mapped in the fi eld. however, since mapping of the raw data (including porosities) does not allow the reconstruction of palaeo-depositional environments, sequential indicator simulations (sis) were applied as a secondary analytical tool. for this purpose, several cut-off values for thickness were defi ned in an effort to distinguish the orientation of depositional channels (main and transitional). this was accomplished by transforming porosities to indicator values (0 and 1) and by applying a non-linear indicator kriging technique such as the “zero” map for obtaining numerous indicator realizations by sis. in the sgs and sis approaches, the simulations encompassed 100 realizations. a representative realization was then selected using purely statistical criteria, i.e., two realizations were almost always chosen in accordance with the order of the calculation. the 1st and 100th realizations were selected for each variable in the sgs and sis and fi ve indicator kriging maps were chosen for the thicknesses cut-offs. keywords: sequential gaussian simulations (sgs), sequential indicator simulations (sis), indicator kriging (ik), sandstone reservoir, kloštar field, sava depression stochastic simulations of dependent geological variables in sandstone reservoirs of neogene age: a case study of the kloštar field, sava depression � kristina novak zelenika1 and tomislav malvić1,2 1sector for geology and reservoir management, ina-oil industry plc., šubićeva 29, 10 000 zagreb, croatia; (kristina.novakzelenika@ina.hr, tomislav.malvic@ina.hr) 2department for geology and geological engineering, faculty of mining, geology and petroleum engineering, pierottijeva 6, 10 000 zagreb, croatia doi: 104154/gc.2011.15 geologia croatica 64/2 173–183 14 figs. zagreb 2011 geologia croaticageologia croatica tions have led to better reservoir descriptions than derived using previous, simpler mathematical models (e.g., malvić & đureković, 2003; smoljanović & malvić, 2004, 2005; malvić, 2005; malvić & velić, 2010). stochastic simulations represent one form of a probabilistic approach aimed at creating a geological model. here we present a fi rst probabilistic approach to croatian hydro1. introduction geostatistics is currently one of the standard geological tools applied in the exploration and development of hydrocarbon reservoirs. as a form of applied statistics, it allows the introduction of mathematical exactness to explain the results. in hydrocarbon reservoirs in croatia, the use of deterministic methods such as kriging, cokriging, and stochastic simulageologia croatica 64/2geologia croatica 174 carbon geology in a systematic application to estimate geological risk. pioneering works on this topic were published in masters theses by frank (1992) and novinc (1992), with research later continued by hernitz et al. (2001) and malvić (2003). the probabilistic approach is exclusively based on the monte carlo algorithm and has long been used as an estimation method in the petroleum industry. the monte carlo approach has been applied to probabilistically calculate hydrocarbon reserves in molve, the largest croatian fi eld, , and in several traps, e.g., the deeper parts of the ferdinandovacvizvar field and prospects in syria. the approach can be very useful in the fi rst stage of exploration, when data from only a few wells are available. stochastic simulation tools that include the monte carlo algorithm represent a logical upgrade to the probabilistic approach as applied in estimating reservoir variables and hydrocarbon reserves. these are deterministic methods that draw on a variogram model and kriging or cokriging as the “zero” or base realization. although interpolation can be made using deterministic methods, mostly by inverse distance weighting, or simple or ordinary kriging, similar results can be obtained with stochastic simulations, by performing estimations (rather than interpolations) through the model’s cells. as in kriging, the stochastic method works on minimizing error estimation, but it also results in uncertainty, which accompanies each location where the estimation is performed. running a simulation is often connected with the later selection of several characteristic realizations. many realizations can be compared cell by cell and for each location, along with a calculated range of minimum and maximum values. there are also other numerical combinations that can be calculated for a set of realizations obtained by simulation. in general, the larger the data-set, the more accurate the obtained statistics. mata-lima (2008) used stochastic simulations (direct sequential simulations and co-simulations) to predict history matching, i.e. permeability distribution. according to the author, sequential simulations of continuous variable in general easily process variable with gaussian distribution or indicator transformation of such variable. but, a direct sequential simulation approach can also reproduce models of co va rian ce, i.e. simulated values can follow a simple kriging estimation, and their variance can match simple kriging variance. furthermore, example of fl uvial sandstone reservoir simulations is described in keogh et al. (2007) on the north sea hydrocarbon reservoir. the authors recommended stochastic algorithms in 3d geological modelling in fl uvial reservoirs, where it is possible, more or less successfully, to show a series of depositional environments characteristic of different lithofacies in fl uvial environments such as channel figure 1: kloštar field, located in the western part of the sava depression. novak zelenika and malvić: stochastic simulations of dependent geological variables in sandstone reservoirs of neogene age: a case study... geologia croatica 175 fi ll, crevasse splays etc. sometimes is even possible to show internal features at the metre scale. stochastic realizations are able to cover multiple scenarios of possible channel distributions, transitions facies or even sedimentation rates. moreover, robertson et al. (2006) also presented algorithms of direct sequential simulations, but which reproduce histograms. the authors also showed experimental semivariograms calculated on a variable (permeability) that is not transformed in normal distribution. results showed that applied algorithms led to given semivariograms very similar to the “regular” (normal distributed) model, but with a lower variogram sill. the fi nal maps reproduced the spatial variability very well. the blocksis software is shown in deutsch (2006). although the wingslib package was used here to obtain the sis maps, it is good to know that there are other options including blocksis, which allows the use of soft (secondary) data from geological interpretations or geophysical measurements. there are nine different techniques (e.g. simple kriging, ordinary kriging, collocated cokriging, block (co)kriging etc.) available in the program. deutsch (2006) described an example tested with all nine techniques, and concluded that it is very diffi cult to decide on the most appropriate approach, although block kriging produced very good results. in cases with clustered data and secondary variables derived from geophysics, some other algorithm could be preferred. here, a stochastic analysis was performed on a dataset collected in the kloštar field (figure 1). this area was previously analyzed by balić et al. (2008) and cvetković et al. (2008), who used geomathematical methods to demonstrate that the most appropriate method for porosity analysis is the kriging interpolation. these authors also establish ed that a geostatistical approach is the most appropriate method for mapping geological variables in all clastic reservoirs of neogene age in the croatian part of the pannonian basin. mal vić & đureković (2003), for example, show ed that, as an interpolation technique, ordinary kriging is better than inverse distance weighting, based on cross-validation, even in the case of a modest input dataset (about 15 points). also, secondary seismic variables enable the use of collocated co kriging for the same size data set. moreover, balić et al. (2008) tested ordinary kriging in a sandstone reservoir of the kloštar field and showed that it was a better interpolation approach than either the inverse distance weighting, moving average, or nearest neighbourhood method. for the kloštar field, the stochastic approach was applied as an analytical tool to estimate three geological variables, porosity, thickness, and reservoir depth, using data collected in the same sandstone reservoir, referred to as “t” (a description of this reservoir is given in balić et al., 2008). this dataset is considered to be representative not only of present-day structural relationships (depth and thickness), but also of the depositional palaeo-environment as recorded in terms of reservoir porosity distribution and thickness. moreover, by carefully selecting mapped data using an indicator approach and the appropriate cut-offs, “hidden” or subtle trends in the distribution of these two variables can be revealed and, consequently, the margins of the distribution system determined. proper selection of cut-offs is especially important in the absence of a clear relationhip between core lithology and average log-porosity values, as was the case in this study, in which only trends were used to select the limit values between marl, marly-sandstone transitions, and sandstone. all other cut-offs were selected using (a) the criteria of a minimum of fi ve cut-offs (novak zelenika et al., 2010) and (b) a larger number of cut-off classes around the median values in the interval between minimum and maximum porosity (or thickness). the “t” reservoir is made up of medium-grained sandstone in its central part, giving way laterally to sandy marlstone at the margins (figure 2). it is the largest sandstone reservoir in a monotonous series of alternating marls and sandstones. it is also referred to as the fi rst sandstone series (informal lithostratigraphic name). the sandstone is of lower pontian age (figure 2) and was deposited in a deep, brackish lake (up to 200 m depth), characterized by a mostly calm environment (deposition of marl) but interrupted periodically by turbidity currents (deposition of sandstones). this depositional system is described in vrbanac et al. (2010). here we examined the ability of stochastic analysis to provide more detailed information on the distribution of reservoir variables than that obtained by kriging, especially in the presence of several irregularly distributed lithofacies that are laterally discontinuous (sandstone, marly sandstone, san dy marl and marl), with borders that are not strictly defi ned. it was postulated that it is more appropriate to defi ne a “fl uid” border using stochastic methods, allowing it to change position in different realizations. this approach is especially valid for understanding reservoir porosity and thickness. the input dataset consisted of 19 data points for thickness, depth, and porosity (figure 3). these points were selected from approximately 100 well points based on criteria obtained from the latest computer analysis of well logs, including average porosity values (previously not calculated), precise, stratigraphically determined reservoir tops and bottoms, and thickness (mostly from e-log markers). 2. the basics of stochastic simulations stochastic simulations comprise a group of geostatistical tools based on an algorithm that differs from interpolation methods. below we provide a short review of sequential gaussian simulations (sgs), which is the stochastic tool most frequently used in the analysis of hydrocarbon reservoirs. our review is based on the theory published in e.g. dubrule (1998), kelkar & perez (2002), and malvić (2008). additional background information can be found in other geostatistical textbooks or references. 2.1. processing of input data and “zero” realization 1. existing measurements (point data from wells) are kept as constant values in each realization. these values are considered “hard data” and the type of simulation is referred to as a conditional simulation. this is in contrast to unconditional simulations, in which “hard” points are also estimated geologia croatica 64/2geologia croatica 176 (and referenced to a cell in which each point value is derived from the surrounding area, including the uncertainty of position). 2. a variogram model is constructed together with input for the kriging interpolation; this deterministic kriging map is called a “zero” realization. figure 2: composite geological column (including stratigraphy, e-logs, and lithology) in the kloštar field (reservoir “t” is located in the sandy marlstone lithofacies). 3. in this type of deterministic solution the following values are always known: a) mean value, variance (µ, σ2) b) kriging variance (σ2 k) c) the interval allowed for simulated values (determined from the relationship between the mean and the variance) novak zelenika and malvić: stochastic simulations of dependent geological variables in sandstone reservoirs of neogene age: a case study... geologia croatica 177 figure 3: thickness distribution (left, scale 0–25 m), porosity (middle, 0–25%), and depth (right, 600–1100 m) hard data. d) if the allowed interval encompasses three standard deviations (±3σ) around a mean (µ) each cell, then 99% of all possible solutions are included. 4. when all previous values are known and the type of simulation is defi ned, then the values of all model “blank” cells can be estimated using the sgs method. 2.2. simulation after normal transformation, the data are most often defi ned by the properties of a normal distribution, n(µ,σ), and an estimation is performed on empty cells. random choice of location is used to estimate one cell (the fi rst introduction of randomness, i.e., stochasticity). the value of the selected cell is estimated mostly by kriging from other points in a spatial model. it is important to note that these points can be hard data or previously simulated points. after a cell is estimated deterministically, a new value is “surrounded” by the interval ±3σ (using the variance of the “zero” solution). using a random choice (the second introduction of randomness), any value from this interval can be accepted as simulated for the cell. the procedure is repeated until the estimates of all cells have been made. 2.3. calculation of a set of realizations the purpose of running a simulation is to obtain an abundant set of realizations, since it is not possible to select one realization as the best, regardless of the criteria applied. it is possible, however, to select “the most appropriate” realization using certain criteria (mostly statistical quartiles or minimum and maximum sums of simulated cells). the large number of realizations in a simulation allows the inclusion of almost all uncertainties, i.e. each cell is sampled with enough values to calculate a reliable, probability density function (pdf). it is of course unnecessary to calculate several hundreds of thousands of realizations as this would be overly time-consuming for simulation and later post-processing. an acceptable number in a simulation is 100 realizations, which is large enough to be representative of the stochastic characteristics of a particular dataset. among these realizations, several can be outlined as useful for modelling purposes; that is, if realizations represent volumes, the letter “p” (probability) followed by a number expresses the percentage of how many of the others have a smaller total volume. for example, p10 means that 10% of all realizations have a smaller volume. as discussed above, the calculation of each new realization means that the order of simulated cells is set completely randomly. the consequence is very interesting, as different realizations for the same cell can be estimated using a different number for the “hard” data inside the variogram ellipsoid. 2.4. advantages and disadvantages of sgs the main advantage of sgs is the possibility of estimating values in all cells of a model through a set of realizations. furthermore, the input data and errors of simulated values are characterized by a normal distribution. the second goal of sgs is to take advantage of new, abundant data to construct a histogram of simulated variables. the resulting histogram is much more reliable than a histogram derived from pure input data. for example, a model based on 50×50 cells and 100 realizations gives 250,000 output values, with an input set made up of only 10–20 measurements. there are, however, disadvantages, e.g., simulated values can be signifi cantly different in neighbouring cells. this may not be a problem in cases with large cells, which may better describe the subsurface than an interpolation. due to the fact that simulation does not have one representative realization, it is necessary to use several criteria from a probability curve to select those that are more characteristically representative. 3. results of sequential gaussian simulations (porosity, thickness, depth) all three selected variables analyzed by the sgs method and the respective results are presented in figures 4–6. for each variable (porosity, thickness, and depth), two realizations were selected using purely statistical criteria, i.e., the 1st and 100th (fi rst and last) calculated realizations. there is a visible trend of higher porosity in a northsouth direction (“stripes” of denser red colour). the respective values are located in the western part of the kloštar field, which is near the deeper part of the sava depression. the higher porosity in the deeper parts of the palaeo-environment corresponds to an area in which more porous sandstone would have been deposited by high-energy turbidity currents. the stochastic maps of thickness shown in figure 5 depict the 1st and 100th realizations. it is interesting, but not geologia croatica 64/2geologia croatica 178 surprising, that the trends are the same as those observed for porosity (figure 4). this suggests that the most permeable sandstones were also deposited in the deeper palaeo-environmental setting; consequently, they are of maximum thicknesses. the values for greater reservoir depth occur where the thicknesses are also greater, suggesting that structural inversion was not completed. it is well-documented (e.g., malvić, 2003; royden, 1988) that, in the pannonian basin, transpression during the pliocene-quaternary inverted many structures, thus accounting for the numerous anticlines and hydrocarbon traps. in the study area, this process occurred only partially, mostly due to the location of the mt. mo slavačka gora, which is a subsurface, uplifted, pre-neogene palaeo-relief located on the eastern side (depicted by the blue zones in figure 6). the sgs results portray a very clear correlation among the trends observed on the maps for each of the three variables (porosity, thickness, and depth). also, the variation between particular realizations is apparent in all three pairs of 1st and 100th realizations. it is important to emphasize that realization nos. 1 and 100 do not mach p1 and p100, because it was impossible to perform depth volume calculations, thus preventing this criterion to be generally applied. according ly, we performed another, purely statistical criterion selection. 4. results of sequential indicator simulations and indicator kriging (thickness) sequential indicator simulation is an alternative estimation method that uses original as well as indicator data for variogram development and mapping. a comparison of figures 5 and 7 shows thickness values mapped by the sgs and sis methods, respectively. it is clear that the sis estimation provides more uniform and lower cell values; consequently, the differences between realizations are not as large as in sgs. figure 5: the 1st (left) and 100th (right) sgs realizations for thickness (scale 0–30 m). figure 4: the 1st (left) and 100th (right) sgs realizations for porosity (scale 0–25%). novak zelenika and malvić: stochastic simulations of dependent geological variables in sandstone reservoirs of neogene age: a case study... geologia croatica 179 figure 6: the 1st (left) and 100th (right) sgs realizations for depth (scale 600–1100 m). figure 7: the 1st (left) and 100th (right) sis realizations for thickness (scale 0–30 m). figure 8: sis probability maps (0-1) for thickness cut-off s of 5 m (left) and 9 m (right). geologia croatica 64/2geologia croatica 180 figure 10: sis probability maps (0–1) for thickness cut-off of 21 m. figure 9: sis probability maps (0–1) for thickness cut-off s of 13 m (left) and 17 m (right). abilities that the cell values are larger than the cut-off, whereas in the ik maps the cell values are less than the cut-off. the contour shapes and interpretation are the same, but the sis maps are “noisier,” with smaller transitions between values (note that the ik map for a 21% cut-off is not interpolated because heterogeneity would be observable only on the scale p=0.990–1.000, which is meaningless). stochastic results through realization allow the calculation of histograms from a more abundant dataset (simulated and hard data), thus offering better insight into variable distribution and statistics. such histograms are shown in figure 13 for porosity and depth, as calculated by sgs, and in figure 14, for thickness calculated by sgs and sis. as expect ed, the variable depth is not characterized by a normal distribution because the fi eld’s structure thins along moslavačka gora, located in the northeast. this implies that the structure occurs in combination with inclined anticlines over a slight monocline dipping towards the southwest. generally, this is apparent on the maps of reservoir bodies (porosity maps) and structures (depth maps) that are mostly oriented north-south. 5. conclusions a stochastic approach is especially useful when the amount of input data is moderate (18–23 points in this analysis), and the variogram models include large uncertainties. when variograms have a large nugget and there is a need for all models to be equal, as in the indicator approach, the stochastic approach will partially remove the “bull’s-eye” effect. this would emphasize interpolation and result in a noisy transition between cell values and hard data. the two histograms in figure 14 were calculated from different simulated sets: sgs (left) and sis (right). as evidenced by the parallel histograms for the thickness of the analyzed sandstone reservoirs, the simulated values calculated by sis are clearly more highly concentrated around the mean value. this also explains why the thickness realizagiven that the original data range is the same (0–30 m), then why does the sis map have more fi nal cell values clo se ly estimated around the mean? the answer is that the variance of an indicator variable is fˆ(zk)∙[1.0 – fˆ(zk)], where fˆ(zk) is the cumulative distribution function (cdf) of the continuous random variable ‘z’, defi ned as fˆ(zk) = pr ob [zk ≤ z].also, fi ve cut-offs were used to defi ne the indicator classes. the greater the number of cut-offs used, the larger the reduction in within-class noise (deutsch & journel, 1998). the intention of using sis was to obtain indicator maps based on stochastic realizations for values higher than that of the selected cut-off (the post-process option in wingslibtm for 100 realizations previously obtained with sis was employ ed.) note that the sis probability maps represent probabilities that a value will be greater than the selected cut-off (figures 8–10). a comparison of the thicknesses on the probability maps obtained with sis (figures 8–10) and indicator kriging (ik) (figures 11 and 12) shows that the sis maps present probnovak zelenika and malvić: stochastic simulations of dependent geological variables in sandstone reservoirs of neogene age: a case study... geologia croatica 181 figure 11: ik probability maps (0–1) for thickness cut-off s of 5 m (left) and 9 m (right). figure 12: ik probability maps (0–1) for thickness cut-off s of 13 (left) and 17m (right). figure 13: histogram of porosity (left) and depth (right) values as calculated by sgs. geologia croatica 64/2geologia croatica 182 figure 14: histogram of thickness values as calculated by sgs (left) and by sis (right). tions in figure 7 are signifi cantly more uniform than those in figure 5 and confi rms the statement that “artifi cial” histograms, which include original and simulated values, need to be calculated from sgs results. a depositional channel is evident in the probability maps obtained by ik and sis, but only for certain cut-off values. in the case of the lower pontian sandstones in the “t” reservoir of kloštar field, this cut-off value corresponds to a thickness of 13 m (figure 12). novak zelenika et al. (2010) reported similar fi ndings when the porosity of the same reservoir was mapped by ik. in those maps, a depositional channel was also seen, but only in the probability map with a 19% porosity cut-off. therefore, for mapping by ik-based methods, an adequate number of cut-off values is particularly important. it is also possible to obtain sis maps with values instead of probabilities. the fi nal cell values of those maps (figure 7) are estimated more closely around the mean and do not indicate the presence of a depositional channel. no depositional channel was observed on maps obtained by sgs; instead, a monocline with several local tops is seen as in figures 4 and 6. higher porosity values occurred in the deepest part of the reservoir as well as in the section of greatest thickness, suggesting that tectonic, i.e., transpression, events starting at the end of the pontian did not result in full inversion in the area of kloštar field. a general conclusion that can be drawn from this study is that sgs can be used in the mapping of structural variables. this is in contrast to ik and sis approaches, which instead described the morphologies of depositional environments in the kloštar field. acknowledment this work represents part of a multidisciplinary geostatistical research project carried out in 2009 and 2010 within the larger project entitled “stratigraphical and geomathematical research of petroleum geological systems in croatia” (project no. 195-1951293-0237), fi nanced by the ministry of science, education and sports of the republic of croatia. references balić, d., velić, j. & malvić, t. (2008): selection of the most appropriate interpolation method for sandstone reservoirs in the kloštar oil and gas fi eld.– geol. croat., 61/1, 27–35. cvetković, m., velić, j. & malvić, t. (2009): application of neural networks in petroleum reservoir lithology and saturation prediction.– geol. croat., 62/2, 115–121. doi: 10.4154/gc.2009.10 deutsch, c.v. & journel, a.g. (1998): gslib – geostatistical software library and user’s guide.– 2nd edition, oxford university press, new york – oxford, 369 p. deutsch, c.v. (2006): a sequential idicator simulation program for categorical variables with point and block data: blocksis.– comput. geosci., 32, 1669–1681. doi: 10.1016/j.cageo.2006. 03.005 dubrule, o. (1998): geostatistics in petroleum geology.– aapg education course note, series #38. kelkar, m. & perez, g. (2002): applied geostatistics for reservoir characterization.– society of petroleum engineers, richardson, 264 p. keogh, k.j., martinius, a.w. & osland, r. (2007): the development of fl uvial stochastic modelling in the norwegian oil industry: a historical review, subsurface implementation and future directions.– sediment. geol., 202, 249–268. doi: 10.1016/j.sed geo. 2007.05.009 frank, g. (1992): procjena perspektivnosti i rizika istraživanja ugljikovodika dijela podmorja mljet.– unpbl. m. sc. thesis, faculty of science, university of zagreb, 115 p. hernitz, z., bokor, n. & malvić, t. (2001): geostatistical modelling of petrophysical data of oil fields in the northern croatia.– abstract book, paper no. p611, 63rd conference & technical exhibition. amsterdam, the netherlands, eage, p. 2. malvić, t. (2003): vjerojatnost pronalaska novih zaliha ugljikovodika u bjelovarskoj uleknini [oil-geological relations and probability of discovering new hydrocarbon reserves in the bjelovar sag – in croatian].– unpubl. phd thesis, faculty of mining, geology and petroleum engineering, university of zagreb, 123 p. malvić, t. (2005): results of geostatistical porosity mapping in western drava depression fi elds (molve, kalinovac, stari gradac).– naf ta, 56/12, 465–476. malvić, t. (2008): primjena geostatistike u analizi geoloških podataka.– ina-industrija nafte, zagreb, 103 p. malvić, t. & đureković, m. (2003): application of methods: inverse distance weighting, ordinary kriging and collocated co-kriging in porosity evaluation, and comparison of results on the benicanci and stari gradac fi elds in croatia.– nafta, 54/9, 331–340. novak zelenika and malvić: stochastic simulations of dependent geological variables in sandstone reservoirs of neogene age: a case study... geologia croatica 183 malvić, t. & velić, j. (2010): relation between effective thickness, gas production and porosity in heterogeneous reservoir and example from the molve field, croatian pannonian basin.– petrol. geosci., 16/1, 41–51. doi: 10.1144/1354-079309-722 mata-lima, h. (2008): reservoir characterization with iterative direct sequential co-simulation: integrating fl uid dynamic data into stochatic model.– j. petrol. sci. engin., 62, 59–72. doi: 10.1016/j.petrol.2008.07.003 novak zelenika, k., malvić, t. & geiger, j. (2010): mapping of the late miocene sandstone facies using indicator kriging.– nafta, 61/5, 225–233. novinc, m. (1992): mogućnosti procjene naftnoplinonosnosti dijela istočne podravine primjenom ekspertnog sustava.– unpbl. m. sc. thesis, faculty of science, university of zagreb, 85 p. robertson, r.k., mueller, u.a. & bloom, m. (2006): direct sequential simulations with histogram reproduction: a comparison of algorithms.– comput. geosci., 32, 382–395. doi: 10.1016/j.cageo.2005.07.002 royden, l.h. (1988): late cenozoic tectonics of the pannonian basin system.– in: royden, l.h. & horváth, f. (eds.): the pannonian basin, aapg memoir, 45, 27–48. smoljanović, s. & malvić, t. (2004): improvements in reservoir characterization applying geostatistical modelling (estimation & stochastic simulations vs. standard interpolation methods), case study from croatia.– proceedings of world petroleum congress, 1st youth forum / committee (ed.). beijing, china: chinese national committee for wpc, 1054–1061. smoljanović, s. & malvić, t. (2005): improvements in reservoir characterization applying geostatistical modelling (estimation & stochastic simulations vs. standard interpolation methods), case study from croatia.– nafta, 56/2, 57–63. vrbanac, b., velić, j. & malvić, t. (2010): sedimentation of deep-water turbidites in main and marginal basins in the sw part of the pannonian basin.– geol. carpath., 61/1, 55–69. doi: 10.2478/ v10096-010-0001-8 manuscript received november 10, 2010 revised manuscript accepted march 05, 2011 available online june 09, 2011 geologia croatica 64/2geologia croatica 184 errata corrige volume 68, issue 1 article “geochemical implications for the magma origin of granitic rocks from the ditrău alkaline massif (eastern carpathians, romania)” by elemér pál-molnár, anikó batki, ágnes ódri, balázs kiss, enikő almási needs correction as follow: pg. 56, right column, third line: the studied granites are mostly alkaline (fig. 5a) and slightly peraluminous in composition (fig. 5b). pg. 58 table 4., rows a/nk, nk/a and a/cnk for all samples contain wrong data and need correction of them into: lo ca tio n la po sb ük k cr ee k la po sb ük k cr ee k la po sb ük k cr ee k tu rc ul ui cr ee k tu rc ul ui cr ee k cr ea ng ă m ar e cr ee k cr ea ng ă m ar e cr ee k cr ea ng ă m ar e cr ee k ţe ng he le r m ic c re ek h ol oş ag cr ee k tu rc ul ui cr ee k h ol oş ag cr ee k m ag as bü kk c re ek jo lo tc a cr ee k jo lo tc a cr ee k jo lo tc a cr ee k w h a le n et a l., 19 87 sample vrg 6835 vrg 6839 vrg 6838/a vrg 7459 vrg 7460 vrg 6847 vrg 6856 vrg 6726 vrg 6842 vrg 7425/a vrg 7458 streckeisen, 1954 morogan et al., 2000 average of 148 samples 1 2 dt 114 dt 112 dt 134 wt. % amphibole-bearing granites  amphibole-free granites  granites granites a/nk 1.17 1.18 1.14 1.00 1.20 1.05 1.10 1.04 1.16 1.09 1.05 1.02 1.16 1.13 1.09 1.08 1.06 nk/a 0.85 0.85 0.88 1.00 0.83 0.95 0.91 0.96 0.86 0.91 0.95 0.98 0.86 0.89 0.91 0.93 0.95 a/cnk 1.06 1.05 1.04 0.97 0.95 1.04 1.05 1.02 1.07 1.05 1.03 0.96 1.15 1.03 1.05 1.05 0.95 pg. 60, according to corrected data, the plots in fig. 5b need correction that are shown in following new diagram: pg. 63, right column, 37th line: (1) dam granites are mostly alkaline and slightly peraluminous in composition. www.geologia-croatica.hr abstract early-intracontinental rifting of pangea was a result of thermal doming in uppermost permian time giving rise to the formation of horst-graben structures, followed by slow subsidence, marine transgression and evaporite deposition. the consequences of incipient magmatism and a high heat flow are numerous geothermal fields and subterrestrial hydrothermal siderite-barite-polysulfide deposits (palinkaš et al., 2016). advanced rifting magmatism as a successive stage in the middle triassic brought intensive submarine volcanism, accompanied by coeval sedimentation of chert and siliciclastics, building up volcanogenic-sedimentary formations. volcanic activity with explosive phases and the generation of large volumes of pyroclastic rocks in the rifts produced concomitant mineralization with numerous sedimentary exhalative (sedex) deposits of fe-mn-ba-polysulfides. the passive continental margin of northern gondwanaland is flanked by the adria-dinaridic carbonate platfom, while the moesian carbonate platform is a counterpart on the european passive continental margin. they were divergently drifted in the course of the advanced rifting. a fast growing carbonate platform, developing gradually, covered evidence of the earlier intracontinental rifting and their ore formations. however, the carbonate platforms themselves host specific pb-zn deposits, well known as a mississippi valley type, (mvt) or bleiberg-mežica type according the traditional european terminology. triassic mvt and sedex deposits are symmetrically situated on the both sides of the divergent passive margins in this early history of the tethyan ocean. the paper gives a brief description of the mvt and sedex deposits, in the two carbonate platforms and rifts in between, formed synchronously and in a similar manner on opposing sides of the diverging continental margin. keywords: triassic mvt pb-zn deposits, sedex deposits, adriatic-dinaric-moesian carbonate platforms, tethyan advanced rifting article history: received december 16, 2015 revised and accepted january 26, 2016 avaliable online february 29, 2016 1. geological framework metallogenesis brings together knowledge of regional geology and ore petrology. their mutual contributions are beneficial to the interpretation of plate tectonics models of orogenic processes (janković & petraschek, 1987; janković, 1997). the alpine-balkan-carpathian-dinaride (abcd) metallogenic and geodynamic provinces are a result of the wilson cycle, which includes phases of early intracontinental rifting (palinkaš, et al., 2010, 2016; strmić et al., 2009), advanced rifting (kiss et al., 2016), oceanization, subduction and emplacement of ophiolites (karamata et al., 1997); collisional and postcollisional deformation events with synkinematic granite plutonism (cvetković et al., 2004). the rifting and oceanization processes took place almost synchronously within the vast circum abcd area, in mid-triassic time, creating the symmetrical emplacement of adriatic-dinaric and moesian carbonate platforms, on the passive continental margins of gondwana and euroasia. the symmetry was emphasized by deep marine basins in between, gradually developing into the oceanic crust of tethys (haydoutov & yanev, 1997). the scenario is outlined by the symmetrical distribution of ore deposits characteristic for the rifting metallogenesis, mvt pb-zn ores in carbonates (bleiberg-mežica type) and sedex iron-manganese-polymetallic ore sediments (red sea type). the early symmetry of the tectonostratigraphic and metallogenic phenomena along the line of extension and opening of the future tethys was subsequently “spoiled” by the continental convergence of africa and eurasia mainly from the middle jurassic, as intra-oceanic subduction, through the middle cretaceous ocean-continent subduction, and upper cretaceous continent-continent collision to the present time. it developed a complex geometry of the collisional interfaces, with interfingering microplates giving rise to discontinuous sutures, diachronous magmatism, and obduction of oceanic crust on the passive continental margin, leading to variable thickening, followed by extension and collapse (heinrich & neubauer, 2002). 75-78 2 figs. doi: 10.4154/gc.2016.06 divergent drift of adriatic-dinaridic and moesian carbonate platforms during the rifting phase witnessed by triassic mvt pb-zn and sedex deposits; a metallogenic approach ladislav a. palinkaš1, zhelyazko k. damyanov2, sibila borojević šoštarić3, sabina strmić palinkaš4 and irina marinova2 1university of zagreb, faculty of science, institute of mineralogy and petrology, horvatovac 95, hr-10000, zagreb, croatia (corresponding author: lpalinkas@geol.pmf.hr, phone: +385 1 3361189) 2bulgarian academy of sciences, institute of mineralogy and crystallography, acad. g. bonchev str., block 107, bg-1113 sofia, bulgaria 3university of zagreb, faculty of mining, geology and petroleum engineering, department of mineralogy, petrology and mineral resources, pierottijeva 6, zagreb, croatia 4university of tromsø, faculty of science and technology, department of geology, dramsvegen 201, n-9037 tromsø, norway vol. 69/1 76 2. the mvt pb-zn (bleiberg-mežica type) and sedex deposits, markers of triassic rifting processes 2.1. mvt pb-zn deposits in the adriatic-dinaridic carbonate platform triassic carbonate-hosted lead-zinc deposits (alpine-type/ mvt) in the alps and dinarides are placed within the adriatic-dinaridic carbonate platform, a passive continental margin of gondwana. carbonate-hosted, low-temperature, pb-zn deposits are contemporaneous with the advanced tethyan rifting in the middle triassic. the most important deposits are those in the northern and southern calcareous alps, bleibergkreuth (zeech & bechstädt, 1994; austria), mežica and topla (drovenik et al., 1980; slovenia), raibl and salafossa (omeneto, 1979; italy). these deposits, so far, provided more than 10 mt of pb-zn metal. the mineralization is generally stratabound in carbonates of the ladinian and carnian stages. usually they are combined under the term “bleiberg type” and have often been compared with mvt deposits (ebner et al., 2000). the discussion of the origin of the pb-zn ores is still controversial. there is a general agreement on their formation by low temperature fluids. the lead model ages older than the host rocks, suggesting metal derivation from the palaeozoic sediments in the autochthonous basement. however, the source and the concentration mechanisms of pb-zn metals deposits are not yet fully understood. apart from the above “majors”, there are more than 200 similar pb-zn occurrences known in the external dinarides, the southern alps and the northern alps. some of them are briefly reviewed below. st. jakob pb-zn deposit hosted by non-metamorphosed dolostones is located on the medvednica mt. in the southwestern part of the zagorje-midtransdanubian zone. the vein-type mineralization has a simple paragenesis, galena, minor sphalerite and pyrite with quartz and calcite as gangue minerals (šinkovec et al., 1988). pb isotopes are anomalous and may be classified as bleiberg-type according to the doe and zartman model, yielding 490 ma (palinkaš, 1985). fi studies in quartz gave the following characteristics: nacl-cacl2-h2o composition, 6-19 wt.% nacl equ., temperature of homogenization (th: 80230°c, mean 130°c). the d34s values of galena and sphalerite vary between +7 and +10 ‰ (bo rojević šoštarić, 2004). pb-zn deposits in the middle triassic carbonates also occur also in the ivanščica mt., in the ivanec deposit, in the zagorje-mid-transdanubian zone (šinkovec et al., 2000), on the eastern slopes of petrova gora mt. in the svinica deposit, and in the srb deposit in the lika region. all of them are accommodated within the units belonging to the mesozoic carbonate platform of the external dinarides. the olovo deposit, central bosnia, is hosted by middle triassic dolostones and limestones, evolved in reefal facies. the major ore minerals are pb and zn carbonates mainly cerussite and to a lesser extent smithsonite (kubat, 1988). 2.2. sedex fe-mn-barite-polymetallic deposits in the dinaridic rift environment vareš metallogenic province in central bosnia owes its ore load to processes during the advanced rifting in the evolution of tethys. coeval magmatism produced spilites, basalts, keratophyres and diabases interbedded with ladinian sedimentary rocks (pamić, 1984; kiss et al., 2016). the vareš deposit with the smreka, droškovac and brezik deposits are taken as the loci typici for mineralization of mid-triassic tethyan rifting. the deposits contain hydrothermal, stratiform sideritehaematite-chert beds. the ore mineralization is intercalated into anisian and ladinian sequences and distinctly zoned vertically, reflecting gradual changes of redox conditions in the depositional environment during basin subsidence. the sequence began with bituminous, thinly bedded black shales with abundant pyrite and base metal sulphides, overlain by barite and siderite, all of which were deposited under reducing conditions. clastic rocks and oolitic limestone rest upon this metalliferous series and are succeeded by another metalliferous series with haematitic shale and siliceous haematite beds, which in contrast to the footwall rocks were deposited under oxidizing conditions. the overall mineralization consists of siderite, mn-enriched haematite, barite, pyrite, marcasite, chalcopyrite, galena, sphalerite, tetrahedrite and pb-sulphosalts. the d34s values of barite vary from +21 to +29 ‰. the chemical compofigure 1. middle triassic advanced tethyan rifting. the drawing depicts the formation of characteristic mvt type of deposits within the carbonate platforms. the sedex type deposits are formed in respons to volcanic activity within a rift basin, including hydrothermal exhalation and deposition of the sedimentary ore load. palinkaš et al.: divergent drift of adriatic-dinaridic and moesian carbonate platforms during the rifting phase witnessed by triassic... 77 sition of fluid inclusions in sphalerite and barite may be described as a cacl2-nacl-h2o system, which evolved under moderately high temperature, (th between 110 and 230°c). salinity ranges from 2 to 4 wt.% nacl equ. in context with the cl/br ratio the fluids are assumed to have been derived from modified seawater (strmić et al., 2001; palinkaš et al., 2003, palinkaš et al., 2008). (fig.1) 2.3. mvt pb-zn deposits in the moesian carbonate platform triassic carbonate hosted pb-zn ore deposits represented by sedmochislenitsi in the moesian carbonate platform resemble in many respects those in the alps and dinarides (minčeva-stefanova, 1972; marinova & damyanov, this issue). the pb-zn stratabound ore deposits occur in the balkanide region within an area of about 30 x 25 km. the host rocks are primarily dolomite of anisian and partly of rhaetian age. the ore bodies are elongated lenses and veins, mostly of metasomatic origin (chernev, 1993). the openings along the bedding were favourable for ore deposition. marl intercalations and thin-bedded dolostone packets were considered to be a screen for the ore fluids (kalaydziev, 1982), while organic matter was a chemical reducer (mincheva-stefanova, 1988). another structural factor is the intense fracturing of sediments near the regional faults. these areas contain rich sulfide mineralization (chernev, 1993). the ore is represented by fine grained light-coloured sphalerite, schalenblende, pyrite, marcasite, galena, small amounts of arsenopyrite, bravoite [(fe, co, ni)s2], and sporadic ag-sb-sulfosalts. dolomite, barite, quartz and calcite are typical gangue minerals. 2.4. sedex fe-mn-barite-polymetallic deposits in the moesian rift environment the kremikovtsi sedex deposit is situated approximately 15 km ne of sofia. it lies in the southernmost part of the kremikovtsi-vratsa ore district, in the western balkanides, a northern branch of the alpine-himalayan collisional orogenic belt. the deposit is a product of middle triassic metallogenesis in the graben shaped structure adjacent to the moesian carbonate platform (bakardziev, s. & popov, p., 1995). the ore forming processes took place in the advanced rift-related extension. the deposit is of the sedex type, consisting of stratiform pyrite and barite ore, and iron-manganese formations with low-grade sulphide mineralization. primary zoning of the kremikovtsi ore district extends vertically and laterally: pyrite, siderite barite, ferroan dolomite, ankerite, and haematite. it has a prominent feeder zone with stockworks and veins of iron carbonates-barite-sulfide in the underlying rocks (damyanov, 1996, 1998). figure 2. metallogenic polarity of mineral deposits, related to the advanced tethyan rifting. the two carbonate platforms, facing each other from the opposite passive continental margins of gondwana and eurasia, accommodate numerous mvt deposits in the alps, dinarides and moesia. the newly formed, deep water marine basin, still with continental (not oceanic crust) is the home of the sedex deposit, formed by hot water, issuing their ore load primarily as sediments on the bottom of the triassic sea. vol. 69/1 78 3. conclusion the area of the alpine-balkan-carpathian-dinaride (abcd) metallogenic and geodynamic provinces is a collage of variable crustal elements, and part of a long suture of the tethyan ocean, squeezed between the gondwanian and eurasian continental blocks. introduction of plate tectonic models greatly contributed to the integrated interpretation of geological evolution in time and space. there are still, however, numerous disputes, in putting collage elements together. the crucial moments in the interpretation are the timing of incipient rifting and the creation of tethyan oceanic crust. a number of oceanic slivers, recognized by dinaridic, west vardar and central vardar ophiolites, make a firm conclusion blurred. metallogenic events, the formation of mvt pb-zn deposits in the adriatic-dinaridic and moesian carbonate platforms, on opposite sides of the rift, and sedex deposits, formed in the rift itself, define spatially and constrain the timing of advanced tethyan rifting, in the mid-triassic. references bakardziev, s. & popov, p. (1995): geological-structural features of the deposit.– in: the kremikovtsi barite-iron deposit and the jurassic system in the region, guidebook, mining and geol. univ., sofia, 2–4; 10–15 (in bulgarian). borojević šoštarić, s., palinkaš, l., strmić palinkaš, s. & spangenberg, j. (2004): mvt-forming brines at st. jakob, medvednica mt., croatia.– in: sassi, f.p. & giobbi, e. (eds.): abstract volume, florence, 2004, 183. chernev, e. (1993): formation conditions of the alpine base-metal ore fields in the vratsa ore unit.– ph.d. thesis, sofia (in bulgarian). cvetković, v., prelević, d., downes, h., jovanović, m., vaselli, o. & pecskay, z. (2004): origin and geodynamic significance of tertiary postcollisional basaltic magmatism in serbia (central balkan peninsula).– lithos, 73, 161–186. doi: 10.1016/j.lithos.2003.12.004 damyanov, z.k. (1996): genesis of the kremikovtsi deposit and metallogenic perspectives of the sredec iron ore region.– geol balc., 26/4, 3–24. damyanov, z.k. (1998): ore petrology, whole-rock chemistry, and zoning of the kremikovci carbonate hosted sedimentary exhalative (+mn)-barite-sulfide deposit, western balkan, bulgaria.– n jb miner abh, 174, 1–42. drovenik, m., pleničar, m. & drovenik, f. (1980): nastanek rudišč v sr sloveniji [formation of mineral ore deposits in sr slovenia– in slovenian].– geologija, 23/1, 1–157, ljubljana. ebner, f., cerny, i., eichhorn, r., goetzinger, m, paar, w., prochaska, w. & weber, l. (2000): mineral resources in the eastern alps and adjoining areas.– mitt. oesterr. geol. ges., 92 (1999), 157–184. haydoutov, i. & yanev, s. (1997): the protomoesian microcontinent of the balkan peninsula – a peri-gondwanaland piece.– tectonophysics, 272, 303–313. doi: 10.1016/s0040-1951(96)00264-8 heinrich, c. & neubauer, f. (2002): cu-au-pb-zn-ag metallogeny of the alpine-balkan-carpathian-dinaride geodynamic province.– mineralium deposita, 37, 533–540. doi: 10.1007/s00126-002-0271-x janković, s. & petraschek, w.e. (1987): tectonics and metallogeny of the alpine himalayan belt in the mediterranean area and western asia.– episodes, 10/3, 169–175. janković, s. (1997): the carpatho-balkanides and adjacent area: a sector of the tethyan eurasian metallogenetic belt.– mineralium deposita, 32/5, 426–433. kalaydziev, s. (1982): new data on the structural peculiarities of the kremikovtsi ore field.– rev. bulgarian geol. soc., 43/2, 159–171 (in bulgarian). kiss, g., molnar, f. & palinkaš, a.l. (2016): hydrothermal processes related to triassic and jurassic submarine basaltic complexes in northeastern hungary and in the dinarides and hellenides (this issue). kubat, i. (1988): genesis of cerussite ore in the ore district „olovo“ near olovo village.– zbor. rad. rud. geol. fak., university of tuzla (in bosnian). marinova, i. & damyanov, z. (2015): the triassic carbonate-hosted stratiform-stratabound base-metal deposits in the western balkan, nw bulgaria, plate tectonics aspects (this issue). minčeva-stefanova, j. (1972): mineral composition and origin of the stratiform polymetallic ore deposits in the balkanides compared with stratiform lead-zinc deposits of the alps.– in: proc. 2nd int. symp. on min. deposits of alps: geology, ljubljana, v. 15, 301–314. minčeva-stefanova, j. (1988): sediment-hosted polymetallic deposits in the western stara planina mt.– in: dimitrov, r. (ed.): the lead-zinc deposits in bulgaria, technika, sofia, 175–192 (in bulgarian). omeneto, p. (1979): significant ore fabric relationships in the lead, zinc, fluorite and barite deposits of the triassic province (italian southern alps).– ann soc geol belg, t 102, 519–529. palinkaš, a.l. (1985): lead isotopes patterns in galenas from some selected ore deposits in croatia and nw bosnia.– geol. vjesnik, zagreb, 38, 175. palinkaš, a.l., strmić palinkaš, s., spangenberg, j. & prochaska, w. (2003): vareš and veovača triassic, fe-pb-zn-ba sedex deposits, related to the advanced tethyan rifting, central bosnia.– in: eliopoulos, d.g. (ed.): proceedings 7th biennial sga meeting, rotterdam: milpress, 1221–1225. palinkaš, a.l., borojević šoštarić, s. & strmić palinkaš, s. (2008): metallogeny of the northwestern and central dinarides and southern tisia.– ore geology reviews, 34, 501–520. doi: 10.1016/j.oregeorev.2008.05.006 palinkaš, a.l., borojević šoštarić, s., strmić palinkaš, s., crnjaković, m., neubauer, f., molnár, f. & bermanec, v. (2010): volcanoes in the adriatic sea: permo-triassic magmatism on the adriatic dinaridic carbonate platform.– acta mineralogica-petrographica field guide series, 8, 1–15. palinkaš, a.l., šoštarić borojević, s., strmić palinkaš, s., prochaska, w., pécskay, z., neubauer, f. & spangenberg, j.e. (2016): the ljubija geothermal field: a herald of the pangea break-up (nw bosnia and herzegovina) (this issue). pamić, j. (1984): triassic magmatism of the dinarides in yugoslavia.– tectonophisics, 109, 273–307. doi: 10.1016/0040-1951(84)90145-8 strmić, s., palinkaš, l.a. & prochaska, w. (2001): ore forming fluids in triassic, rifting related sedex deposits, vares and veovaca, central bosnia.– in: antal, á. et al. (eds.): pancardi 2001 meeting, sopron. geodetic and geophysical research institute of the hungarian academy of sciences, p. 16. strmić palinkaš, s., spangenberg, j.e. & palinkaš a.l. (2009): organic and inorganic geochemistry of ljubija siderite deposits, nw bosnia and herzegovina.– mineralium deposita, 44, 893–913. šinkovec, b., palinkaš, l. & durn, g. (1988): ore occurrences on the medvednica mt.– geol. vjesnik, zagreb, v. 41, 395–405 (in croatian). šinkovec, b., palinkaš, l. & durn, g. (2000): lead-zinc ore occurrences on the ivanščica mt. near ivanec (croatia).– rudarsko-geološkonaftni zbornik, v. 12, 11–14 (in croatian). zeech, s. & bechstädt, t. (1994): carbonate hosted pb-zn mineralization at bleiberg-kreuth (austria): compilation of data and new aspects.– sp publication, 10, soc geol app miner deposits, fontboté/boni (eds): sediment hosted zn-pb ores. springer verlag, berlin, heidelberg. ab stra ct the experiences of developing engineering geological models in karst areas for designing and construction purposes prove the necessity of considering at least three basic submodels: sedimentological, structural-tectonic and the weathering one. the research presented here deals with very important and frequently neglected segments in each of the submodels. therefore, particular attention should be directed to: better understanding of carbonate sediment deposition, determination of environment and diagenetic processes, study of the 3d anisotropy of discontinuity frequency, and differentiation of weathering zones. the given data and examples elaborate and justify such an approach, which enables a more realistic detailed engineering model, more reliable evaluations of the engineering geological/geotechnical parameters and real site conditions. keywords: engineering geological model, karst, limestone, anisotropy, heterogeneity, discontinuities, weathering, croatia  specific aspects of engineering geological models in croatian karst  davor pollak, dražen navratil and tomislav novosel department of hydrogeology and engineering geology, croatian geological survey, sachsova 2, hr-10000 zagreb, croatia; (davor.pollak@hgi-cgs.hr; drazen.navratil@hgi-cgs.hr; tomislav.novosel@hgi-cgs.hr) doi: 10.4154/gc.2013.17 1. introduction the engineering geological model of the construction project area is a very important segment of geotechnical design. creation of an engineering geological model for geotechnical designs is usually based on experience, known data, various field observations and measurements, and assumes common engineering geological, laboratory testing, geophysical surveying and borehole researching. this paper elaborates on the main geological issues observed at many investigation sites, while developing engineering geological models for the main motorways in the croatian karst, at the rijeka-zagreb and zagreb-split-dubrovnik sections having together more than 400 km in length (fig. 1). the paper does not deal with detailed elaboration of every input data for future models, but with the generically important and sometimes neglected emphases that are found in building the engineering models for carbonate rocks. it is also the intention to document how the authors came to deal with the great heterogeneity of carbonate rock material and the heterogeneity/anisotropy of carbonate rock mass engineering properties. geologia croaticageologia croatica figure 1: location map showing the recent distribution of adriatic carbonate platform (adcp) deposits (according : vlahović et al., 2005) and investigated areas along new motorways. geologia croatica 66/3 219–232 13 figs. 3 tabs. zagreb 2013 geologia croatica 66/3geologia croatica 220 2. geological setting the croatian karst area encompasses approximately 29,356 km2, or nearly 50% of the land surface of the republic of croatia. carbonate rocks compose the central, coastal and submarine croatian territory (fig. 1). these sediments mainly originate from the adriatic carbonate platform (adcp). the large carbonate platform in this area started to develop during the upper triassic. during the early jurassic period, it disintegrated into several smaller platforms, one of which was the adcp (vlahović et al., 2005). carbonate sedimentation in relatively calm and shallow marine conditions at the adcp lasted during the mesozoic until the late cretaceous. afterwards, carbonate sedimentation was prolonged under somewhat different conditions until the eocene. the great thickness of carbonate sediments, (3500 -5000 m in croatian territory), proves the constant subsidence of the carbonate platform during deposition (herak, 1991). other factors, including the variability of the depositional environment and emersion periods, also testify to the significant dynamics of the whole carbonate platform. tectonic activity between the cretaceous and the paleogene initiated regional emersion and termination of the platform sedimentation. therefore during the eocene, carbonate rocks were deposited at the margins of the disintegrated platform (vlahović et al., 2005). in addition, the flysch basin had been formed and the dinarides uplifted. the uplifting of the dinarides reached its maximum between the oligocene and miocene. the final result of formation of the dinarides was an area with strongly faulted and crushed zones, reverse and overlapped contacts (herak, 1986). since the beginning of the neotectonic episode, the adriatic region continued to sink while the dinarides uplifted (prelogović et al., 2003). later, more intensive uplifting caused erosion of the dinarides and deposition of thicker sediments in depressions. the quaternary deposits either cover neogene sediments or are deposited directly on older bedrock. karst is an area of specific hydrogeology and morphology which is characterized by sinkholes, caves and karst poljes, predominantly generated by the chemical weathering of carbonate rocks. the area of dinaric karst has been investigated since the middle of the 19th century and it is considered as a „locus tipicus”. therefore, some local terms for specific karst features are accepted worldwide. mature and extreme karst with a great depth of karstification processes in croatia is actually the consequence of lithology, tectonics, and action of water and climate conditions during geological history (herak et al., 1969; bahun, 1974; prelogović, 1975; herak & bahun, 1979; herak, 1991; fritz, 1991; vlahović et al., 1999; vlahović et al.; 2005). according to up to date knowledge, karstification of carbonate rocks in the adcp occurred during many emersion periods in the mesozoic. however, more intensive karstification on a regional scale occurred during the upper cretaceous – tertiary, middle and late eocene and oligocene periods (herak et al., 1969). the pleistocene age is very important for dinaric karst development because the tectonic and hydrogeological processes enabled the formation of karst poljes, (herak et al., 1969; pavičić & renić, 1992) which are the largest karst phenomena. 3. the basic postulations for developing an engineering geological model the croatian karstic area is a region of great variability of rock properties and geological situations affecting engineer ed design. this variability is three-dimensional and it affects all dimensions of the project from one geologic model unit to another. therefore, before developing a model in a carbonate rock mass, an engineering geologist should first differentiate the geological elements that control the engineering properties and character of the construction ground: lithostrati graphic units, rock material types, structural-tectonic blocks, discontinuity sets, karst morphological features, weathering intensity and weathering „zones”. therefore, field mapping activity needs to identify the expected critical data types how such data will be observed and collected so that rock material and rock mass properties can be noted and processed separately for each of the aforementioned elements. when this plan is completed, the engineering geological report will relate strictly to the design needs of the proposed engineered construction. upon differentiation of the aforementioned geological elements, the authors propose the development of three models: a sedimentological model, structural model and weathering model. the final engineering geological model will be the synthesis of these models. 3.1. sedimentological model in carbonate rocks, most of the parameters set out above are investigated during sedimentological investigations meaning that the sedimentological model must be developed before the engineering model (pollak & braun; 1998 pollak, 2002). it is important to first define the expected lithostratigraphical units of the project site or route alignment. the geological column should contain the basic descriptions of the major relevant sedimentological properties including: mineral composition, lithology, bedding thickness, interbeds, regularity of boundaries, structure, texture and porosity. in most cases, similar lithostratigraphic units can be merged according to their relevant engineering geological properties and conditions in order to set up engineering geological units. the usual method is to make a reconnaissance inspection of the project area or route and to take representative laboratory samples of each apparent rock-unit material. these samples are than subjected to „index” testing in order to gain the first approximation of the gross engineering character of each apparently different rock mass. it has been found that limestone texture can be ideally classified according to dunham (1962), enabling a unified and simple description of rock material, according to depositional texture observed directly in the field. depositional textures, furthermore, then lead to recognition of the parent pollak et al.: specific aspects of engineering-geological models in croatian karst geologia croatica 221 depositional environment and of later diagenetic processes. the importance of these factors in an engineering-geological modelling is paramount, because most of these effects have degraded (weakened) the limestone rock material. considering the sedimentary nature of the limestone, each single unit is scrutinised for evidence of carbonate microfacies. units are often composed of several irregular vertical or lateral alterations of different microfacies, which cannot be considered as separate units. therefore we use microscopic determination to reveal valuable details about the rock material: mineral and microfossil composition, texture, porosity, cementation, diagenesis, weathering and secondary defects including micro-fissures and cracks. the basic limestone and dolomite micro-textural properties are defined according to folk, (1959). the limestone microfacies determination is further done according to standard microfacies types (smf) (flügel, 1982). the authors have found that carbonate rock materials in croatian karst are frequently structurally modified both by intensive diagenetic processes, as well as having frequent numeric defects due to intensive tectonics. when this form of „damage” is noted, the smf should be modified and some new microfacies types added. 3.2. structural model the structural model now is used as a means of defining the presence of structural blocks, determined on the basis of separate discontinuity sets (of joints, as planar discontinuities) orientation and their spacing. the discontinuities are found in mutually rhombic sets of two attitudes, each set caused by a single palaeotectonic deformational phase during geological history. these are the main planar breaks of weakness that define each structural block (also called structural domains). in the investigated area of carbonate rocks, four tectonic phases that conditioned the evolution of tectonic blocks were present (matičec, 2009). the most significant tectonic activities took place in the upper jurassic period, when the phase of compression tectonics started. in the late cretaceous period the structures with a nne-ssw strike were formed (laramian orogene). in late eocene and oligocene the final uplift of the dinarides mountain range began, along with formation of structures with strike nw-se (pyrenean orogene). consequently, the middle and upper miocene neotectonic phase followed, when regional stress assumed a general orientation n-s (matičec, 2009). the relationships between the representative unit block (structural domains and major rock blocks) and the spatial position of the linear infrastructure constructions are considered here. the construction of new linear infrastructure in bedrock terrain often produces new, fresh rock faces in road cuts which are of prime consideration. this new planar face sometimes creates the fourth face of a new tetrahedral block of rock that can be acted upon by gravity, and thus becomes unstable at the highway cut, or in a more limited sense, at the face or crown of a tunnel, during the construction process. the intensity of rock mass fracturing has fundamental importance regarding its great potential negative instability influence on rock mass characteristics before, during and after excavation. therefore, evaluation of the discontinuity frequency has usually been performed during the field investigations for any important building structure or mining project. in many areas, it is possible to collect such data exclusively by drilling. however, the usage of a single value for the linear frequency (discontinuity number determined per the unit line length in the defined direction through the rock mass), is generally not enough to ensure the corresponding intensity of the fracture quantification for the needs of the engineering design. for the rock mass which contains a definite number of sets of parallel, planar and persistent discontinuities, hudson & priest (1983) showed that the discontinuity frequency could be reduced to a single vector, as a rock mass property. for an example of the rock mass which contains n discontinuity sets, they also showed that their frequency along the scan line of any orientation is given with the expression: 1 cos n i s i il l q = = ∑ (1) where qi represents the angle between the scan line and the normal of the i-set of the discontinuity set, li is the frequency of the i-set of the discontinuity along the normal of that set where li is defined as the reciprocal value of the mean value of the discontinuity spacing 1 /x l= , and ls represents the total frequency along the determined scan direction. from this method of processing the orientation and frequency of discontinuity sets determined by the investigation field works, it is possible to determine the maximum and minimum values of the linear frequencies, their directions in three dimensions, i.e. to define the plane of the greatest anisotropy or define the afore mentioned values for the directions which are characteristic and important for a particular linear object. usage of the rqd index as one of the engineering measures for classification of the fractured rock masses is widespread because of the easy measuring way on the outcrops and borehole cores. the analytical expression for the mutual relationship of rqd and random joint spacing, i.e. frequencies, is presented by priest & hudson (1981) using the negative exponential distribution. harrison (1999) sets up the analytical determination of the threshold value which he prefers to the arbitrary threshold value which is used in practice (0.1m), and which is not sensitive to the whole range of the discontinuity spacing, i.e. frequencies which are met in practice. the use of the optimal rqd index threshold value greatly expands the range of rqd values encountered in rock mass and as such increases the fidelity and hence the discriminatory nature of rqd. on the basis of the exponential model, according to priest & hudson (1981) and the values of minimum lmin and maximum lmax discontinuity frequency, harrison (1999) suggested the function for determining the optimal threshold value by means of the given formula: max max min min 2*t h l l l l   = ⋅  −   (2) geologia croatica 66/3geologia croatica 222 the simple classification of the rock masses for the purposes of engineering works such as tunnel construction, excavations, foundations etc., (which can be done by means of the rqd values), has been known and used practically for a long time. what’s more, rqd presents an important parameter for the categorization of the rock masses developed according to bieniawski (1973, 1989) and barton et al. (1974). the connection of rqd with the fundamental characteristics of the rock structure, i.e. their discontinuity frequency resulted in its widespread practical application. in literature, different statistical models for evaluation of the rock mass quality, priest &hudson (1976), kulhawy (1978), sen (1984), have been suggested. these models were used for connecting rqd with the mean discontinuity number or with the average length of the intact core parts. one such model, which is based on the usage of the negative exponential distribution for the modelling of discontinuity spacing, was presented by priest & hudson (1976). this model has been shown to be rather limited in the geological application (sen, 1984), with one of the main limiting factors being the basic property of the exponential distribution that its mean value is equal to the standard deviation. namely, there are numerous situations in nature where such equality is not valid. because the distribution of the intact parts lengths cannot be limited to the exponential distribution, the need to investigate other distributions is imposed. priest & hudson (1976) and sen (1984) showed that the analytical curves for rqd index opposite to l obtained on the base of the probability density function (p.d.f.) of the negative exponential distribution stand in the diagram almost always higher than the measured data, i.e. they overestimate the value of the rqd index. sen (1984) noticed that the standard deviation of the intact parts length plays an additional important role in the rock mass quality classification, i.e. an increase in the standard deviation improves the rock mass quality. he therefore suggested the log-normal distribution as the more appropriate model for connecting the rqd index with the average number of discontinuities, where the expected rqd is expressed by the formula: ( ) 1( ) 100 1 2lnx lnx ln te rqd f l s s    = − − +       (3); in which slnx = standard deviation of the logarithmic intact lengths, l = mean number of discontinuities, t = threshold value and f(•) = standardized normal probability distribution function. in this model e(rqd) and l are implicitly connected because the parameter l originates from the poisson distribution. figure 2, initially published by sen (1984), shows the relationship between rqd and l for two distributions (where t = 0.1 m): – lognormal distribution with different values of s lnx (two parameter distribution); – exponential distribution (single parameter distribution). lognormal distribution shows that rqd cannot be judged solely on the basis of mean intact length but, additionally, the standard deviation of the intact length must be considered. this property could not be identified with the negative exponential distribution. the mutual relationship of rock quality designation (rqd) and the discontinuity frequency in carbonate rocks based on analytical models reported in the literature has also been considered and analyzed. 3.3. weathering model the existing and generally used weathering engineering classi fication of karst ground (fookes & hawkins, 1988; waltham & fookes, 2003) is mainly based on the number and size of karstic features and hydrogeological characteristics of the area. this classification is adequate and sufficient on a regional scale. an engineering geological model at a detailed scale, e.g. 1:1000 or 1:5000 requires additional thorough investigations of the weathering intensity of the rock mass regarding overburden depth. this aspect of weathering in karst is frequently neglected despite its obvious indicators and earlier studies (deere & patton, 1971; novosel et al., 1980). unlike other, indissoluble rock materials, carbonate rock material in this area demonstrates the minor influence of weathering to its mechanical and physical properties (pollak, 2007), due to rapid and effortless weathering progress along numerous discontinuities. therefore, most of the investigations of the weathering processes in karst should be directed toward discontinuity properties from the surface zone into the interior. 4. results despite the continuous deposition of carbonate rocks in shallow and low energy environments, anomalous deposition conditions were encountered through the investigated area, which were acted upon by later diagenesis, intensive tectonic deformation, and weathering processes. it is our observation figure 2: rqd variation with l for lognormal p.d.f. pollak et al.: specific aspects of engineering-geological models in croatian karst geologia croatica 223 that even subtle differences in the depositional environment of individual carbonate sediments, led to the creation of major heterogeneities and anisotropy that affect the final engineering of the highways. the authors here bring forth some important model findings, as gained from their route characterization work in carbonate rock masses (fig. 1). 4.1. sedimentological model detailed hand specimen evaluation, thin-section analysis, and the basic ucs testing usually explains the very high range of rock material mechanical properties and need for subdivision of the units. for example, it is very important to determine uniaxial compressive strength (ucs) of both crystalline and stromatolitic segments from the upper triassic dolomite – "hauptdolomit" (t3 2,3). the same dolomite in the gorski kotar region, is present along more than 5 km of the zagreb to rijeka motorway. stromatolitic dolomite represents about 10–20% of the dolomite mass, but its lower uniaxial strength and laminated texture disrupts the homogeneity and isotropy of the rest of the rock mass having a higher uniaxial strength (tab. 1). the difference between the mechanical properties of the crystalline and stromatolitic dolomite is significant, especially in weathered rock material. in the area between the maslenica settlement and the "sveti rok" tunnel (13 km of motorway), microscopic analysis confirmed the assumptions on close association of carbonate rock material strength and its microfacieses (figs. 3, 4). despite the fact that just several samples were analyzed, some trends were noticeable. firstly, a very strong and complete degree of calcite cementation made for a good and tight fit between the coarse grains of neocomian limestone breccias (1d), which is the main reason for its greater strength in comparison to the other lower cretaceous (neocomian) limestones (1a, b, c). the uniaxial compressive strength of recrystallized (2a) and dolomitized (2d) segments of upper cretaceous (cenomanian) limestones has been significantly reduced in comparison to its parent materials (2b). promina table 1: uniaxial compressive strength of different microfacies segments of "hauptdolomite" in gorski kotar region (pollak & braun, 1998). dolomites uniaxial strength / mpa texture (num. of samples) mean range crystalline (46) 85 39-131 stromatolite (8) 43 26-60 figure 3: subdivision of engineering geological units according to microfacies determination with appropriate microphoto. zagreb-split motorway, section tunnel st. rok-maslenica. geologia croatica 66/3geologia croatica 224 carbonate rocks (4) consist of poorly sorted conglomerates (4a) and uniformly graded calcarenites (4b). while considering these deposits, the significantly lower uniaxial compressive strength of conglomerates should be noted (fig. 4). as opposed to the calcarenites, the matrix of the conglomerates is of variable quality and locally even porous which is, besides the grain size, considered to be the main reason for the lower strength of the conglomerate. at this point we were rewarded with the fact that determination of subunits was possible on the basis of detailed field notes and some laboratory index property testing. in order to bridge the gap to the engineering geological recommendations, some of the sedimentological properties required consideration from the engineering perspective, e.g. the bedding thickness. there are numerous examples to support the thesis of the influence of depositional and diagenetic conditions on the rock material and rock mass engineering properties. one of the most obvious examples is the influence of bedding thickness on block sizes of the carbonate rock mass. bedding is the consequence of changes in physical, chemical and biological conditions of sedimentary facies and diagenetic processes (collinson & thompson, 1989). therefore a layer is considered to be a geological body separated from the surrounding rock mass by changes in its original grain-size distribution, mineralogical composition, lithological proprieties, orientation or pattern of particles or simply, by the termination of sedimentation. from the sedimentological perspective, the layer isn’t always bounded with discontinuities while considering the sedimentary rocks in engineering sense it is usually very important to measure exclusively the spacing (frequency) of bedding discontinuities. the importance of such an approach can be confirmed in many segments, but here it is elaborated through determination of the average field measured joint block size and shape in carbonate rocks. based on the data from 32 mega lithostratigraphic units across the adcp (3760 measurements of bedding thickness and 678 locations of block size calculations), the analysis confirms the assumption that the „engineering bedding thickness” in the investigated area greatly affects the spacing of the secondary sets of discontinuities and naturally also the block sizes (fig. 5). the diagram also shows the average block shapes, which are dominantly slightly tabular in well bedded, or equidimensional in the poorly bedded carbonate rock mass. 4.2. structural model as previously stated, more than half of the croatian territory is composed of carbonate deposits, i.e. a great number of linear infrastructural objects have been built in carbonate deposits in the last 15 years. here, data collected in field inve stigations for the needs of geotechnical design are analys ed, by means of the models mentioned in the previous section, with the aim of improving the definition of the en gineering geological model. the collected data, which were obtained during the core drilling and engineering geological mapping for the design needs of important tunnels in carbonate deposits, were analyzed (the segment of representative input data are presented in table 2). several lithographic units in the carbonate deposits were processed, where the blocks can generally be divided into equidimensional and tabular ones regarding the shape. in table 3, the calculated minimum and maximum discontinuity frequencies, as well as their directions and planes of maximal anisotropy are presented. table 3 also contains the calculated values of the discontinuity frequencies based on the surface data in the direction of the performed drilling hole and strike of the designed tunnel axis. it is obvious from the data that the equidimensional blocks have lower maximum anisotropy regarding the discontinuity frequencies in different directions than the tabular blocks, which can be expected with regard to the block geometry itself. the values of the discontinuity frequencies and other parameters from tables 2 and 3 are presented in the following items, for two characteristic block types (equidimensional and tabular) which most often appear in carbonate rocks. figure 6a presents the orientations of the separate discontinuity sets and the axis of the tunnel "mala kapela" for structural unit a – equidimensional block (fig. 6c). in figure 6b the 3d frequency values in all possible directions for the determined sets and their associated mean spacing are presented, the plane of maximum anisotropy is distinguished, figure 4: the ranges and averages of uniaxial compressive strength (ucs) for particular microfacies (19 samples in total). zagreb-split motorway, section tunnel sveti rok-maslenica. figure 5: correlation of the average bedding discontinuity spacing and block size in the croatian carbonate rocks from the middle triassic to the oligocene (continuous line). dashed line represents ideal, calculated equidimensional blocks. pollak et al.: specific aspects of engineering-geological models in croatian karst geologia croatica 225 table 2: example of discontinuity orientation, strike of tunnel axis and frequency data for two characteristic block types analyzed for the design needs of tunnels in carbonate rocks. structure structural unit number of sets discontinuity orientation (dip direction / dip angle) normals of discontinuity sets (trend / plunge) strike of tunnel axis mean discontinuity spacing (m) mean frequency (m–1) tunnel “mala kapela” a 3 148/37 050/77 306/67 328/53 230/13 126/23 3 – 183 0.78 1.05 0.94 1.28 0.95 1.06 b 3 170/23 210/75 160/77 350/67 030/15 340/13 28 – 208 0.78 1.05 0.94 1.28 0.95 1.06 e 3 179/22 025/70 092/80 359/68 205/20 272/10 41 – 221 0.58 0.98 1.01 1.74 1.02 0.99 i 3 270/13 200/70 292/69 090/77 020/20 112/21 41 – 221 1.17 1.08 1.32 0.85 0.93 0.76 k 3 190/15 259/73 318/78 010/75 079/17 138/12 17 – 197 1.17 1.08 1.32 0.85 0.93 0.76 tunnel “umac” a 3 208/48 018/49 107/88 028/42 198/41 287/2 88 – 268 0.56 0.69 0.64 1.79 1.46 1.56 tunnel “brinje” d 3 59/13 241/77 182/79 239/77 061/13 002/11 18 – 198 0.21 0.89 0.54 4.78 1.13 1.84 d 4 59/13 241/77 182/79 129/84 239/77 061/13 002/11 309/6 18 – 198 0.21 0.89 0.54 0.54 4.78 1.13 1.84 1.84 e 3 103/13 248/80 181/89 283/77 068/10 001/01 20 – 200 0.17 0.78 0.86 5.97 1.27 1.17 e 4 103/13 248/80 181/89 300/83 283/77 068/10 001/01 120/07 20 – 200 0.17 0.78 0.86 0.86 5.97 1.27 1.17 1.17 table 3: global minimal and maximal frequency with their orientation and plane of maximal anisotropy, frequencies in direction of drilling, tunnelling direction and optimal threshold values for two characteristic block types of tunnels designed in carbonate rocks. structure structural unit / number of sets min. frequency (m–1) max. frequency (m–1) orientation of min. frequency (trend / plunge) orientation of max. frequency (trend / plunge) plane of extreme frequencies (max. anisotropy) calculated frequency in direction of drilling (m–1) mean frequencies from boreholes (m–1) calculated frequency in tunnelling direction (m–1) calculated optimal rqd threshold value (m) tunnel “mala kapela” a / 3 1.00 2.17 220/10 290/20 281/20 1.65 4.6 1.79 1.32 b / 3 0.72 2.80 250/5 0/35 334/38 1.66 5.5 2.00 1.31 e / 3 0.92 2.55 115/10 265/55 202/73 2.13 8 2.02 1.25 i / 3 0.65 1.91 285/15 65/50 8/66 1.42 4.1 1.17 1.71 k / 3 0.64 1.89 175/15 95/40 103/40 1.25 3.25 1.02 1.74 tunnel “umac“ a / 3 1.52 3.03 195/45 55/5 142/59 2.21 3.45 2.52 0.91 tunnel “brinje” d / 3 1.02 5.56 95/10 5/70 9/70 5.26 10.1 3.35 0.75 d / 4 2.48 6.33 95/10 335/60 10/65 5.46 10.1 4.01 0.48 e / 3 1.27 6.36 145/10 355/70 57/80 6.06 6.4 2.11 0.63 e / 4 2.15 6.66 30/5 295/55 304/55 6.20 6.4 2.27 0.50 geologia croatica 66/3geologia croatica 226 and the direction of borehole as well as the strike of the tunnel axis are marked. figure 7 provides a similar presentation for the tabular block (fig. 7c), i.e. structural unit e in the "brinje" tunnel (fig. 7a and b). figure 7b), which evidently shows a greater anisotropy of frequency for the tabular blocks. according to the equation [2], for the calculation of an optimal threshold value of rqd, it is necessary to determine the value of the minimum and the maximum discontinuity frequency (l min and l max), with regard to the given orientations of the defined sets and their spacing (table 3). figures 8 and 9 present the polar plot of discontinuity frequency in the plane of extreme frequencies and differences in the discriminatory nature of the rqd index for the customary thres hold value and calculated optimal threshold values for the structural units analysed in figures 6 and 7. figure 6: the "mala kapela" tunnel – structural unit a (3 sets): a) equal angle lower hemispherical projection of example data, b) three-dimensional locus of discontinuity frequency with plane of extreme (range) frequencies, c) equidimensional blocks. figure 7: the "brinje" tunnel – structural unit e (3 sets): a) equal angle lower hemispherical projection of example data, b) three-dimensional locus of discontinuity frequency with the plane of extreme frequencies, c) tabular blocks. pollak et al.: specific aspects of engineering-geological models in croatian karst geologia croatica 227 to establish the connection between the rdq index and the average number of discontinuities (frequency), the afore mentioned exponential and log-normal model was applied. the data was collected from cores of 46 boreholes, drilled during the design phase of an important tunnel, through massive to thick layered limestones of cretaceous age. the reason those rocks were chosen is because the data on all the intact length (not only of longer than 0.1 m) were available, which is necessary for the estimation of s lnx. highly fractured and cavernous zones were excluded during the calculation of rqd and average number of discontinuities. results of the analysis confirm the justification of the log-normal model usage, as opposed to the exponential one, for the purpose of connecting these two parameters (rqd vs. average number of discontinuities – l) (fig. 10). lognormal function of the probability density is defined with the formula [3] where the standard deviation of the logarithmic intact lengths s lnx = 0.78. 4.3. weathering model despite the enormous importance of karstification processes on engineering problems in the croatian karst, that segment of engineering-geological model is not the focus of this paper. the main superficial (sinkholes) and subterranean (ca ves, caverns) karstic features have been studied by many authors (šarin & hrelić, 1984; kapelj, 1985; božičević et al., 1995; jamičić & novosel, 1999; waltham & fookes, 2003; kapelj et al., 2004; garašić, 2005; figure 8: the "mala kapela" tunnel – structural unit a (3 sets): a) polar plot of discontinuity frequency; b) polar plot of rqd using customary threshold value 0.1 m and optimal threshold value. figure 9: the "brinje" tunnel – structural unit e (3 sets): a) polar plot of discontinuity frequency, b) polar plot of rqd using customary threshold value 0.1 m and optimal threshold value. geologia croatica 66/3geologia croatica 228 bostjančić et al., 2011) and their results should be acknowledged in engineering design encompassing karstified media. here, the influence of weathering processes on general discontinuitiy properties and rock mass quality is considered. the carbonate rocks in croatia are predominantly very "pure", with more than 92% carbonate mineral content. carbonate composition and other properties of the area, including low primary porosity of rock material (< 5%), the thickness of the carbonate sediment complex, tectonics and climatic conditions enabled intensive weathering of the carbonate rocks and the formation of karst. the probable "zoning" of the carbonate rock mass should be examined during the investigation phase for the engineering geological model. initially that is usually done by thorough engineering geological mapping. in the later phases the "zoning" should be verified with geophysical investigations and core drilling. most of the analyzed geophysical profiles which are done in the investigation phase for the croatian motorways across the adcp display surprisingly ‘regular’ zones. the compilation histogram of 54 shallow refraction seismic profiles with total length of 4160 m, displays clear zones in the limestone rock mass (fig. 11). regarding the relatively shallow maximum reach of several decametres in most analyzed geophysical profiles, three zones can be noted: swz – surface weathering zone; uwz – upper weathering zone; lwz – lower weathering zone. it is also obvious that fresh rock mass, with expected vp > 6000 m/s is rarely reached as a minor segment in lwz. despite the clearly visible zoning in figure 11, determination of the weathering zones at the specific location shouldn’t be based on geophysical investigations alone. the weathering processes and the discontinuity properties characteristic for each weathering zone can usually be recognized in the borehole core. besides the obvious variation of weathering marks at the discontinuities in borehole core, it is also noted that rqd values can show a trend of block size change as an indication of weathering intensity related to the rock mass depth. from the extensive amount of borehole data (based on 2930 intervals in 463 boreholes with the total drilled interval of 4877 m), the trend of block size increase with depth is clearly visible (fig. 12). still, it is important to say that such clear zoning is rarely visible in boreholes on smaller and extremely karstified areas. the ‘zoning’ of engineering properties in the karst area is mainly a consequence of changes in the width and infilling of discontinuities. namely, from the fresh rock to the strongly weathered rock mass, the width of discontinuities increases significantly but the infilling also generally changes from none, over carbonate through clayey to none. this leads to the derivation of characteristic weathering zones in the croatian karst, which can usually be incorporated in the engineering-geological model (fig. 13). the definition of the weathering zones in this model are mainly based on these two factors – the width and infilling of discontinuities. figure 10: variation of the rqd index versus l for exponential and lognormal probability density function (p.d.f.) in croatian carbonate rocks (upper juras sic up to upper cretaceous limestones and dolomites). figure 11: the distribution of the primary seismic waves velocities (vp) in different weathering zones in limestones across the adcp. figure 12: the histogram of rqd index values in relation to the depth of the drilled interval from boreholes across adcp. pollak et al.: specific aspects of engineering-geological models in croatian karst geologia croatica 229 5. discussion the main objective during the engineering geological processing of the field and laboratory data is the synthesis of geological data and quantitative parameters for use by the design engineers. the synthesis of all the available data should produce an engineering geological model, which contains all the important engineering data and presents it in simple and practical way. the authors advocate that beside the studies of the characteristic karstic morphological features, there are other very important segments of the engineering geological model of karstified rocks: the sedimentological, structural and weathering model; which enables a better and more reliable definition of weathered rock mass properties and quality. in that sense, the engineering geologist’s eye must seek and appreciate mineral composition, formation, diagenesis, rock material texture, structural discontinuities and the evidence of alteration and/ or weathering which tends to degrade the basic engineering properties and parameters of each rock-mass unit. engineering sedimentological modelling in carbonate rocks begins with detailed field observations and microscopic investigations of samples selected as being representative of each apparent three-dimensional rock mass unit. here the field-data collection needs are: unit lithology, geometry of the sediment body, texture, structure, bedding plane properties and bedding thickness. at the beginning of the field mapping and data collection stage, there is the natural challenge of making a preliminary evaluation of the likely impact of different factors on the engineering character of rock masses to be encountered. most of the carbonate rock mass in croatia is bedded and the rock mass therefore has a basic anisotropy, and this requires constant attention to the need to identify three-dimensional block parameters, particularly as it affects the direction not only of motorways, but of all other linear infrastructural projects. with regard to the anisotropy of the discontinuity frequency in different directions, the question is whether the vertical boreholes drilled during the geotechfigure 13: characteristic weathering zones in croa tian karst with corresponding basic descriptions. (photo examples are from the "mala kapela" tunnel area). geologia croatica 66/3geologia croatica 230 nical design of the tunnels give a real evaluation of the rock mass, i.e. if they underestimate or overestimate the fracturing of the rock mass in the direction of tunnel excavation? according to the presented data, the anisotropy of discontinuity frequency in equidimensional blocks is insignificant while in tabular blocks it is strongly expressed, especially in the case of the usual three sets of discontinuities, each resulting from a separate but severe historical phase of regional tectonism. taking into consideration the realistic example (fig. 6), the vertical core drilled at the "brinje" tunnel underestimates the rock mass quality in the direction of the tunnel excavation concerning the fracturing state. in addition to the calculation, this was proven by comparing core logging data with data obtained during excavation of the tunnel. also, the mean values of the discontinuity frequencies obtained by core logging, in the majority of examples presented in table 3; do not match the calculated frequencies in the drilling direction. the reasons for this can be manifold: 1) the "in situ" rock mass is disturbed during the drilling process, i.e. the obtained core contains more fractures than are visible on the walls of the borehole due to fracturing or opening along cracks where weakened part in the intact rock exists; 2) the objective impossibility of collecting enough qualitative data concerning the discontinuity orientations and their spacing on the surface. therefore, it is not possible to reliably define the mean values of the set discontinuity orientations, i.e. the size and shape of the unit block, only on the basis of the surface data. the impossibility of collecting sufficient qualitative data is often connected with weathering in the surface zones, coverage by quaternary deposits and with a smaller blocks size on the surface, caused by the process of chemical weathering of the carbonate rocks. errors in defining the aforementioned parameters directly influence the results of the calculated frequencies obtained in the determined direction. so the most appropriate model should consist of reliably defined mean values of sets orientations and their frequencies. therefore, it is necessary to bear in mind that the model for the analysis of the discontinuity frequency is based on three basic assumptions: • rock mass structure is composed of planar sets of parallel discontinuities; • all discontinuities are strictly planar, which is not the true case; • each discontinuity is persistent along the observed area. using the analysis of the optimum threshold value of the rqd index, according to harrison (1999) it is clear that its usage maximises the range of values of the rqd index, which is marked in the rock mass and as such it increases the reliability and consequently the discriminative nature of the rqd index. it is also clear from the diagram (fig. 10) that the exponential model overestimates the rqd values for the analysed data, while the log-normal model is more justifiable regarding the security in geotechnical design in carbonate rock masses. however, it is necessary to have all the intact lengths for the estimation of s lnx. given the specific weathering mechanisms, the weathering zones in extremely karstified areas are frequently irregular. therefore, the expression "weathering zone" shouldn’t be literally used in karstic regions. it is often the case that the separated environments mutually interlace and irregularly exchange vertically and laterally. irregular "zoning" appears on the large faults or in tectonically fractured areas, where borders with other zones could be vertical or even inverse. depending on the geological properties of the investigated area, the weathering zones in karst have very different characteristics, spreading and mutual relationships. therefore, it is difficult to judge the differentiation of the "zones" of variable degrees of weathering in the carbonate rock mass, because of its great irregularity in every sense. there are also usually great differences in discontinuity properties from the outcrop zone to the greater overburden depth of several hundred metres which should be quantified in the engineering geological model. in general, weathering is most intensive at the surface zone where mainly the chemical but also physical action amplifies the appearance of the joint sets, which then appear to be open, and there are usually frequent wide discontinuities. in the areas with deeper overburden, the same discontinuity sets can be closed or even disappear. therefore, in the carbonate rock mass one should expect an increase of block size (and a related decrease in spacing frequency) with the rise of overburden depth. this is visible in numerous cuttings along the newly built motorways in croatia. 6. conclusions beside the general and well known procedures for building the engineering geological model in any rock mass, a carbonate rock mass demands some additional perspectives. if we adopt the regional model which quantifies the karstification intensity of the area, the detailed investigations should also enable development of three main submodels: 1. sedimentological, 2. structural and 3. weathering. here, some very important aspects of each submodel are studied and presented respectively. 1. the total understanding of the history of sedimentation provides explanation and answers about engineering behaviour and properties of both rock material and rock mass. therefore, the sedimentological investigations of carbonate rocks are greatly improving the creation of the engineering geological model because they enable more precise and logical differentiation of engineering units through the described procedure. the microfacies are characteristic for strictly defined depositional environments and later geological conditions and they are proven to have a major influence on the many engineering properties of carbonate rock material and mass. therefore, the definition of microfacies usually leads to better comprehension of the variability in mechanical properties in carbonate rock material of each of the engineering geological units. 2. the determination of the extreme values of the discontinuity frequencies has successfully been applied in planning the sampling strategy by drilling, different classificapollak et al.: specific aspects of engineering-geological models in croatian karst geologia croatica 231 tions and general understanding of the mechanical and hydrological characteristics of the fractured carbonate rock masses. based on the considerable quantity of data from the boreholes in the massive to thick layered limestones of cretaceous age, the justification supposition of the log-normal model usage was confirmed as opposed to the exponential one with the purpose of rqd connecting with the average number of the discontinuities. 3. despite clearly visible weathering zoning in the carbonate rock mass on a great amount of data it is very important to stress that weathering "zones" in croatian karst are very irregular in space and in almost every other parameter, as it is typical for all dinaric karst areas. still, creation of the detailed and valid engineering geological model of a karstified area should include consideration of possible weathering zones and its engineering properties. four weathering zones regarding the properties of discontinuities and weathering marks are characteristic: fresh rock mass (i, frm), lower weathering zone (ii, lwz), upper weathering zone (iii, uwz) and surface weathering zone (iv, swz). determination of the geological genesis of each threedimensional rock mass is the key to understanding the overall condition of the rock for present construction. once completed, this leads to the most accurate determination of the rock material and rock mass engineering properties and prediction of post-engineering behaviour. references bahun, s. (1974): tektogeneza velebita i postanak jelar-naslaga [tectogenesis of the velebit and genesis of jelar deposits – in croatian]. – geol. vjesnik, 27, 35–51. barton, n., lien, r. & lunde, j. (1974): engineering classification of rock masses for the design of tunnel support.– rock mechanics, 6, 183–236. bieniawski, z.t. (1973): engineering classification of jointed rock masses.– transactions of the south african institution of civil engineers, 15, 335–344. bieniawski, z.t. (1989): engineering rock mass classifications.– john wiley & sons, new york, 251 p. bostjančić, i., pollak, d., podolszki, l. & gulam, v. (2011): the geological setting of the sinkholes in bare croatian karst.– in: laverov, n.p. & osipov, v.i. (eds.): engeopro, environmental geosciences and engineering survey for territory protection and population safety, proceedings, moscow, 179–184. božičević, s., šaban, b. & vulić, ž. (1995): podzemne šupljine u temeljima objekata na području rijeke [underground cavities in the foundations of buildings in rijeka – in croatian]. – in: vlahović, i., velić, i., šparica, m. (eds.): first croatian geological congress, proceedings, 1, 121–124. collinson, j.d. & thompson, d.b. (1989): sedimentary structures.– unwin hyman, boston-sydney-wellington, 207 p. deere, d.u. & patton, f.d. (1971): slope stability in residual soils.– 4th pan-american conference on soil mechanics and foundation engineering, proceedings, san juan, puerto rico, 87–170. dunham, r.j. (1962): classification of the carbonate rocks according to depositional texture – classification of carbonate rocks american association of petroleum geologists memoirs, 1, 108–121. flügel, e. (1982): microfacies analysis of limestones.– springer-verlag, berlin-heidelberg, 633 p. folk, r.l. (1959): practical petrographic classification of limestones – bulletin of american association of petroleum geologysts, 43, 1–38. fookes, p.g. & hawkins, a.b. (1988): limestone weathering: its engineering significance and a proposed classification scheme.– quarterly journal of engineering geology, 21, 7–31. fritz, f. (1991): utjecaj recentnog okršavanja na zahvaćanje voda [the impact of recent karstification on water extraction – in croatian]. – geol. vjesnik, 44, 281–288. garašić, m. (2005): speleological research of caverns in trace of the highways in croatian karst.– in: velić, i., vlahović, i., biondić, r. (eds.): third croatian geological congress, abstracts book, opatija, 191–192. harrison, j.p. (1999): selection of threshold value in rqd assessments.– international journal of rock mechanics and mining sciences, 36, 673–685. herak, m. (1986): a new concept of geotectonics of the dinarides.– acta geologica, croatian academy of sciences and arts, 21, 35– 83. herak, m. (1991): dinaridi: mobilistički osvrt na genezu i strukturu [dinarides: mobilistic review of the genesis and structure – in croatian].– acta geologica, 21/2, 35–117. herak, m. & bahun, s. (1979): the role of the calcareous breccias (jelar formation) in the tectonic interpretation of the high karst zone of the dinarides.– geol. vjesnik, 31, 49–59. herak, m., bahun, s. & magdalenić, a. (1969): pozitivni i negativni utjecaji na razvoj krša u hrvatskoj [positive and negative influences on the development of karst in croatia – in croatian].– krš jugoslavije, 6, 45–78. hudson, j.a. & priest, s.d. (1983): discontinuity frequency in rock masses.– international journal of rock mechanics and mineral science & geomechanics abstracts, 20/2, 73–89. jamičić, d. & novosel, t. (1999): the dynamics of tectonic modeling of some caves in the karst region (croatia).– geol. croat., 52/2, 197–202. kapelj, j. (1985): neki rezultati primjene geomorfološke analize reljefa u uvjetima krškog terena [some results of the application of geomorphic analysis of relief in karst terrain – in croatian].– geol. vjesnik, 38, 121–129. kapelj, j., kapelj, s. & singer, d. (2004): spatial distribution of dolinas and its significance for groundwater protection in karst terrain.– xxxiii international association of hydrogeologists congress, proceedings, mexico, 1–4. kulhawy, f.h. (1978): geomechanical model for rock foundation settlement.– journal of geotehnical engineering division, asce, 104, 211-228. matičec, d. (2009): krški dinaridi [karst dinarides – in croatian] – in: velić, i. & vlahović, i. (eds.): tumač geološke karte republike hrvatske 1:300000, hrvatski geološki institut, zagreb, 105–106 p. novosel, t., tušar, z., mulabdić, m., garašić, m. & koražija, s. (1980): ocjena stabilnosti kosina u zasjecima (usjecima) građenih od karbonatnih stijena [rating stability in notches (cuttings) built of carbonate rocks – in croatian].– zbornik radova 5. simpozija jugoslavenskog društva za mehaniku stijena i podzemne radove, 1, 185–192. pavičić, a. & renić, a. (1992): recent karstification and water drainage from bakovac valley (lika, croatia).– geomorphology and sea, proceedings of the international symposium, mali lošinj, 127–133. pollak, d. (2002): ovisnost inženjerskogeoloških svojstava karbonatnih stijena o njihovim sedimento-petrološkim značajkama (trasa jadranske autoceste: "tunel sveti rok – maslenica") [dependence of engineering-geological properties of carbonate rocks on their geologia croatica 66/3geologia croatica 232 sedimentary-petrological characteristics (adriatic highway section: "tunnel sv. rok – maslenica") – in croatian].– unpubl. msc thesis, faculty of mining, geology and petroleum engineering, zagreb university, 108 p. pollak, d. (2007): utjecaj trošenja karbonatnih stijenskih masa na njihova inženjerskogeološka svojstva [influence of the carbonate rock masses weathering on their engineering-geological properties – in croatian].– unpubl. phd thesis, faculty of mining, geology and petroleum engineering, zagreb university, 299 p. pollak, d. & braun, k. (1998): sedimentology in the service of engineering geology: study of some results of the explorations for highway construction and tunneling in croatia.– in: moore, d. & hungr, o. (ed.): proceedings, rotterdam: a. a. balkema, 195–199. prelogović, e. (1975): neotektonska karta sr hrvatske [neotectonic map of the croatia – in croatian].– geol. vjesnik, 28, 97–108. prelogović, e., pribičević, b., ivković, ž., dragičević, i., buljan, r. & tomljenović, b. (2003): recent structural fabric of the dinarides and tectonically active zones important for petroleum-geological exploration in croatia.– nafta, 55/4, 155– 161. priest, s.d. & hudson, j.a. (1976): discontinuity spacings in rock – international journal of rock mechanics and mineral science & geomechanics abstracts, 13, 135–148. priest, s.d. & hudson, j.a. (1981): estimation of discontinuity spacings and trace length using scan-line survey.– international journal of rock mechanics and mining sciences, 18, 183–197. šarin, a. & hrelić, đ. (1984): ocjena hidrogeoloških svojstava karbonatnih naslaga na temelju gustoće ponikava u niskom i dijelu visokog krša hrvatske [the evaluation of hydrogeological properties of carbonate sediments on the basis of sinkhole density in low and high karst of croatia – in croatian].– vii jugoslavenski simpozij, budva, zbornik radova, knjiga 1, 117–125. sen, z. (1984): rqd models and fracture spacing – journal of geotechnical engineering, asce 110/2, 203–216. vlahović, i., velić, i., tišljar, j. & matičec, d. (1999): lithology and origin of tertiary jelar breccia within the framework of tectogenesis of dinarides some carbonate and clastic successions of the external dinarides.– harlod reading’s ias lecture tour, 23–25. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeography, main events and depositional dynamics.– palaeography, palaeoclimatology, palaeoecology, 220, 333–360. waltham, a.c. & fookes, p.g. (2003): engineering classification of karst ground conditions.– quarterly journal of engineering geology and hydrogeology, 36, 101–118. manuscript received february 08, 2013 revised manuscript accepted september 26, 2013 available online october 28, 2013  definition of the river gacka springs subcatchment areas on the basis of hydrogeological parameters  jasmina lukač reberski1, tamara marković1 and zoran nakić2 1 croatian geological survey, sachsova 2, 10000 zagreb, hrvatska; (jlukac@hgi-cgs.hr) 2 faculty of mining, geology and petroleum engineering, pierottieva 6, 10 000 zagreb, hrvatska doi: 10.4154/gc.2013.04 geologia croatica 66/1 39–53 12 figs. 4 tabs. zagreb 2013 geologia croaticageologia croatica ab stra ct the river gacka springs catchment area is located in the dinaric karst, which is globally known as the locus typicus, or classical karst. it is composed of four major and several minor karst springs of different discharge rates. the river gacka springs are characterised by great discharge and exceptional quality, so the catchment area of the river is indicated in the water management strategy (official gazette no. 91/08) as an area with strategically important reserves of drinking water for the republic of croatia. to determine the hydrogeological characteristics of the subcatchments of this large and complex aquifer system, hydrological and hydrochemical parameters were measured on the main springs. data collected on the springs were analysed using the recession analysis by the „matching strip“ method, the statistical analysis of a time series of measured data both by autocorrelation (analysis of individual series) and by cross-correlation methods (analysis of interrelationships between time series), multivariate statistical analysis (factor analysis) of hydrochemical parameters using the software package statistica 6.0 (1998), and geochemical modelling of hydrochemical parameters using the netpath computer program. interpretation of lithological, structural and tectonic characteristics of the rocks, together with tracing data and the applied analytical methods, allowed the springs catchment of the river gacka to be divided into three subcatchments. the results of this study imply the necessity of a multidisciplinary approach to research. keywords: hydrogeology, karst spring, hydrology analysis, hydrogeochemistry, river gacka springs 1. introduction the catchment of the river gacka springs is located in the croatian part of the dinaric karst, which represents the karst locus typicus. the catchment consists of four major (tonković, majerovo vrilo, klanac and pećina) and several minor springs (jaz, marusino vrilo and graba) of different discharge rates. the gacka springs are characterised by a high discharge and exceptional water quality, which was why this catchment area was proclaimed by the water management strategy (official gazette no. 91/08) as one of the strategically important area of drinking water reserves of the republic of croatia. the research area is characterised by features of typical karst geomorphology. research and data collection is difficult due to the heterogeneity of the karst aquifer, as well as the unknown geometry of the voids through which the water flows underground to the springs. in addition, with a size of approximately 500 km2 the river gacka springs catchment area is categorised as a „big catchment” (kendall & mcdonnell, 1998), which further complicates the study. results of previous hydrological and hydrogeological studies (pavičić et al., 2003; lukač reberski, 2008) have shown that the river gacka springs catchment area can be divided into subcatchments of the main springs. former detailed hydrological analyses were performed on the basis of hydrological data measured only on the profiles of the river gacka (bonacci & andrić, 2008; lukač reberski, 2008). hydrograph analyses performed based on these data are related to the reaction of the entire aquifer system to precipitation, while the characteristics of particular sub-parts of the catchment remain unknown. therefore, detailed hydrological analyses were performed geologia croatica 66/1geologia croatica 40 on the most important springs (tonković, majerovo vrilo, klanac and pećina), providing new insight on this complex and strategically important karstic hydrogeological system. the investigations and the results presented here are part of an extensive and systematic hydrogeological study described within the authors’ phd thesis (lukač reberski, 2011). 2. geographic, climatologic and geomorphologic characteristics the investigated area can be described as a hilly karst area with a large karst polje (gacka polje) surrounded by the ve­ lebit, kapela, and plješivica mountains. the highest altitudes (<1200 m.a.s.l) belong to the central part of the karst hinterland, whereas the river gacka springs formed at the lowest altitude, (~450 m.a.s.l). locally, the relief plays a key role in the definition of climate conditions. high mean values of annual air temperature are the highest in croatia. there is also a significant difference in the spatial distribution of precipitation. these, are the direct result of the orographic characteristics of the study area. the mean annual air temperature ranges between 4 and 9°c, (zaninović et al., 2004) while the annual mean precipitation values range between 1000 and 2500 mm (gajić­čapka et al., 2003). the research area is characterised by typical karst geomorphology i.e. karst features are distinguishable in the relief (karrens, sinkholes, caves, karst poljes, karst springs, estavelles, sinks). 3. geological, hydrogeological and structural-tectonic characteristics the study area is composed predominantly of carbonate rocks with fractured and fracture-cavernous porosity. over the wider area of the river gacka springs catchment, various jurassic and cretaceous limestones and dolomites predominate. the great permeability of the limestone is the direct result of its fragmentation caused by intense tectonics, as well as by the lithological constitution which enables dissolution processes. besides the carbonates, tertiary clastites, i.e. jelar deposits (bahun, 1974) are also abundant in this area, and can be observed overlying the carbonates, sometimes as only a few metre thick erosional remains, or up to several hundred metre thick deposits. these deposits are represented by limestone breccias made of unsorted jurassic, cretaceous and palaeogene sediment fragments (vlaho­ vić et al., 2009). the jelar formation has specific hydrogeological characteristics and, due to its lithology and spatial distribution, a specific hydrogeological function. the presence of marly-matrix breccias intercalated with marl lenses led to two opposing hydrogeological effects i.e. firstly the unusually well-developed surface and underground karst phenomena, and secondly the formation of relatively less permeable environments (bahun & fritz, 1975). these deposits can be observed at the bottom of the polje near the river gacka spring, as well as in the western part of the catch ment. fine-grained sediments with intergranular porosity occur in the form of the quaternary cover in poljes and depressions and they do not have an important hydrogeological influence. lithology had an essential role in the formation of the hydrogeological properties, especially permeability (lukač re berski et al., 2009). hence, based on their permeability the deposits are divided into: – very permeable carbonate rocks, which are the most common types, and where limestones of jurassic and cretaceous ages prevail; – predominantly permeable rocks are represented by other jurassic and cretaceous carbonates and palaeogene clastites, i.e. the jelar deposits. the jelar deposits exhibit about 50% less permeability than the jurassic and cretaceous carbonates, which surround them (bahun & fritz, 1975); – predominantly impermeable rocks – comprising of dolomites of jurassic and cretaceous periods; – impermeable deposits include the eocene marls occurring in a very small region in the eastern part of the investigated area; – variably permeable deposits are quaternary deposits with heterogeneous properties, as their permeability varies depending on the thickness and composition. they are represented mostly in the depressions of karst polje. one of the most important, and currently unsolved, karst problems is determining the boundaries and the surface of the catchment, for which classical geological and hydrogeological approaches are necessary but not always sufficient. hydrological approaches may provide answers to some questions regarding the size of the catchment surface but cannot imply the position of the boundaries (bonacci, 1995). unlike a topographic water divide, determination of the groundwater divide in karst terrain depends on many factors. furthermore, the groundwater divide is not constant as its po sition changes depending on the groundwater level (žugaj, 2000). therefore a multidisciplinary research approach and data collection is required in order to precisely determine the location of the divide and the size of the catchment. several tracings tests were carried out using the na­fluorescein artificial tracer to determine the apparent velocities and groundwater flow directions as well as the size of the catchment area. tracing test results, performed between 1957 – 2010., were presented in unpublished technical reports. recent investigations suggest that the surface of the gacka catchment up to the čovići profile extends to 516 km2 (biondić et al. 2010). groundwater­flow directions depend more on the structural relationships than on the lithological characteristics because of the relatively monotonous lithology. the study area is characterized by the nw–se dinaric strike of the structures. tracings showed that the groundwater flow direction in the greater part of the catchment area is parallel to these structures. this is due to the position of the main boundary faults, favourable to the stress direction (20°–45°), and along which the right transcurrent shifts appear, apart from the opening up of spaces and appearance of structures of a pullapart type (prelogović, 1989). a fault direction unfavourable to the stress direction leads to local compression by closing of the space and possible prevention of water flow (fig. 1). lukač reberski et al.: definition of the river gacka springs subcatchment areas on the basis of hydrogeological parameters geologia croatica 41 4. hydrological characteristics the river gacka is characterized by favourable hydrological conditions. the flow regime is standardized compared to other karst rivers, and considerable variations of the flow quantities through its river bed do not occur. the ratio of the lowest, medium and highest discharge is 1:4:20, whereas the ratio of the neighbouring lika river is 1:100:800 (bonacci, 1987), which shows its vividly torrential character. during the monitoring period (2008 – 2010) the amount of precipitation varied, with 2008/09 being considered as an average year when compared to the long term average, where as 2009/10 was wetter. the average annual discharge during the monitoring period, (determined from data collected on the gacka river gauge at čovići podgora, fig. 1), was 13.44 m3s–1 of which 29% is related to the tonković spring, 26% to the klanac spring, 24% to the majerovo vrilo spring, 15% to the pećina spring and 6% to the remaining springs (fig. 2). recent investigations of the hydrological balance of the catchment indicated the significant retention properties of the karst underground system in the river gacka catchment figure 1: schematic hydrogeological map of the study area, showing sampling sites (position of the study area in detail). 1– very permeable rocks, 2– predominantly permeable rocks, 3–predominantly impermeable rocks, 4– most important faults, 5– extension zone, 6– swallow hole (ponor) and vertical cave (pit), 7– spring: permanent and intermittent, 8– groundwater divide, 9– borehole, 10– groundwater connection (tracer test), 11– river, 12– river and rain gauge stations, 13– groundwater velocity determined by tracing tests (cm/s). geologia croatica 66/1geologia croatica 42 (lukač reberski, 2008). therefore the water balance of the catchment should be prepared over longer time periods because it provides more reliable discharge coefficient information. due to the inadequate distribution of rain gauge stations (fig. 1) in the river gacka springs catchment, mean an nual precipitation was calculated using the regression equation defined for the research area (gajić­čapka et al., 2003). this equation also takes into account the precipitation change with altitude as all the rain gauge stations in lika are below 760 m.a.s.l. and most of the catchment is located at higher altitudes. mean annual precipitation is 1383 mm while the mean catchment discharge is determined from 30 years of daily discharge data (1972 – 2002), so the mean annual discharge in the profile of the hydrologic gauge station čovići­podgora is 14.2 m3/s. the discharge coefficient c can be defined as follows: (1) where q is the mean discharge (m3s–1), t is duration of the mean discharge (s), p is the amount of precipitation (m), and a is the surface of the catchment (m2). the discharge coefficient of the catchments calculated using the above formula is 0.63, which means that 63% of total precipitation in the catchment infiltrates into the ground and flows towards the river gacka springs. 5. methods and research techniques to determine the dynamic characteristics of the springs to determine the dynamic characteristics of individual springs and their catchments, daily water discharge rates were collected between 2005 – 2010 from the meteorological and hydrological service of croatia (dhmz). due to the extreme ly heterogeneous characteristics of the karst aquifer, spring runoff hydrographs were used because they refer to the total response of the aquifer to precipitation (padilla et al., 1994). analysis of spring hydrographs is both a cheap and very useful method in hydrogeological research, especially for karst aquifers. both the recession parts as well as the complete hydrographs were analysed. recession analysis refers to the analysis of the falling limbs of the runoff hydrographs. the advantage of the recession method is that it does not need prior knowledge of the distribution of the potential and the individual parameters of the aquifer, although the recession coefficient directly depends on them. recession curves mostly represent only part of the dynamic reserves of the aquifer, depending on the initial water level. the total water volume stored inside the aquifer can be much higher. numerous authors have publicised the usefulness of this method (tallaksen, 1995; dewandel et al., 2003; bakalowicz, 2005). in the case of long recession periods, which a lack of heavy and long precipitation periods, the recession curve could provide good insight into the structural characteristics of the aquifer. both the shape and the characteristics of the recession curve, i.e. the calculated recession coefficient (α) values, imply the hydrogeological characteristics of the aquifer and are dependent on various factors, among which the most important are: porosity type, hydrological conditions, i.e. the water level as well as the rate of water supply from other aquifers. if the α values are larger than 10–2 a rapid drainage system is indicated, with large fractures and channels; when the α value is smaller than 10–2, slow drainage from smaller pores and fractures may occur, i.e. it indicates that the rock matrix has the dominant role in the water flow through the karst underground (krešić, 1997). for recession analysis, it is of major importance that the recession period lasts for a long time period, at least for several months. such a case has never been registered for the region under study. precipitation during the recession period results in various shapes of the recession curves for the same spring. therefore, analysis of a single recession period on a spring is not the most appropriate method for drawing major conclusions regarding the aquifer and groundwater supplies. to overcome this problem the modified „matching strip” meth od was used (posavec et al., 2006) for recession analy­ sis on the monitored springs. this method includes analysis of all recession events of the runoff hydrograph, allowing construction of a main recession curve. in some cases, curves with a lower coefficient of determination describe the recession more appropriately, and this can be easily determined visually (riggs, 1968). so the main recession curve, which has the highest coefficient of determination, is not always the best selection. therefore, the final regression model is selected on the basis of both, experience and the existing software. recessions with two, three and sometimes even more discharge micro-regimes are quite common in karst aquifers (bonacci, 1987). such recession curves can be easily separated. for this purpose software was used for the automatic separation of the main recession curve of the monitored springs (posavec et al., 2010; parlov, 2010). the programme is based on the analysis of the duration curves of mean daily discharge, i.e. on determining the critical discharge where the slope of the curve changes abruptly. analyses of complete hydrographs consist of statistical analysis of time series data (box & jenkins, 1974). this figure 2: proportion of discharge from the river gacka springs between 2008 – 2010. lukač reberski et al.: definition of the river gacka springs subcatchment areas on the basis of hydrogeological parameters geologia croatica 43 method was introduced by mangin (1981, 1984) to the karst hydrology and subsequently improved by padilla et al. (1994). numerous authors have used this method for defining karst systems (larocque et al., 1997, 2000; tomasko et al, 2001; panagopoulos & lambrakis, 2006; fiorillo & doglioni, 2010; stroj, 2010; terzić et al., 2011)., autocorrelation and cross­correlation meth ods are used for the time series analysis of the springs, which is the aim of the current research (davis, 2002; borradaile, 2003). the characteristics of the springs catchment, the relationships between springs and the dependence between the precipitation in the catchment and the spring discharge were all determined using these methods. the autocorrelation function represents the linear relationship of the successive data values inside a time series, dependant on their time distance (box & jenkins, 1974; terzić et al., 2011). the autocorrelation method is based on the intercorrelation of data from a time series, with a successive increase of time distances, whereby the degree of similarity between the data for each step is calculated. autocorrelation for the distance τ corresponds to the covariance of all measurements xt and the measurements with a time distance xt + τ according to the equation: (2) where cov τ is the covariance for a time distance, x is the time series, n is the number of measurements in a time series, τ is the time distance between two measurements, is the average value of the sample. the autocorrelation coefficient (rx) ranges from a maximum of 1 to the minimum of –1. the autocorrelation value of 1 means that the compared time series are identical. the time needed for the decrease of the correlation coefficient below 0.2 is called the „memory effect” mangin (1984), and reflects the duration of the reaction of the system to the input signal. interpretation of the autocorrelogram should be undertaken with care, because the shape of the autocorrelogram depends, not only on the characteristics of the karst system, but also on the duration, frequency and the intensity of the rain (grasso & jeanine, 1994; eisenlohr et al., 1997). to establish the places of pronounced similarities i.e. similarities between individual data, it is possible to compare two different time series in the same way one time series is compared with itself for a particular time lag. from such comparisons it is possible to obtain two kinds of information: the strength of the connection between these two time series and the time delay between them at the places of maximum similarity. the cross-correlation equation is similar to the autocorrelation coefficient equation. if two time series are marked as variables x and y, and n is the number of pairs which are compared in one step (k) of the cross-correlation, than the cross­correlation coefficient is as follows: (3) 6. methods used for defining the hydrogeochemical characteristics of spring waters between february 2008 and november 2010, water samples were collected from four springs (tonković, pećina, majerovo vrilo and klanac). prior to sampling, the following parameters of the sample waters were measured ‘’in situ’’ by probes from the wtw company: electrolytic conductivity (ec), temperature (t), ph and oxygen content. water samples (500ml) were collected for measurements of basic cations, anions and alkalinity. samples (100ml), were also collected for measurements of stable isotopes (δ18o and δd). the samples were collected under different hydrological con ditions, with a total of 16 samples per spring for basic cations and 25 samples for stable isotope measurements. basic cations and anions were measured in the hydrogeochemical laboratory, department of hydrogeology and engineering geology of the croatian geological survey. con centrations of sodium, potassium, magnesium and calcium were measured using the atomic absorber type aas analyst 700 by perkin elmer. nitrate, orthophosphate, sulphate and chloride ions were measured using the ion chromatograph by laballiance. bicarbonate ions were measured by titration. from the chemi cal composition of the water, interactions between the rock-mass and groundwater can be determined, as can the underground retention time of the water. besides the natural processes, the water composition is also influenced by pollution, especially by nitrates found in artificial and natural fertilizers. understanding of the reactions between the water and environmental substances introduced to it allows anticipation of the dangers/harmful influences of pollutants on water quality, and hence the influence on the human health and/or the health of the ecosystem. the ratios of the stable isotopes deuterium (dd) and oxygen (d18o) in the sampled waters were measured using the mass spectrometar by finnigan delta plus xp i delta plus in the joanneum research resources, institute of water, energy and sustainability, department of isotope hydrology and environmental analytics in graz (austria) and in the physics department of the school of medicine in rijeka (croatia). these ratios are used in hydrogeological research to determine the recharge area and the hydrodynamic conditions, i.e. changes in water velocity in discrete parts of the aquifer and the hydraulic connection between separate aquifers (doctor et al., 2000; vandenschricka et al., 2002). in nature the differences in the ratio can be seen in the phase transitions in the water media. therefore, variations of the isotope ratios in the groundwater are the result of seasonal changes, the altitude of the recharge area, proximity to the sea, intensive rain showers and isotope exchange with the rock-mass. the linear dependence between the stable isotopes oxygen-18 and deuterium in precipitation was recognized by friedman (1953), while craig (1961) defined this dependence with the following formula: dd = 8 · d18o + 10 (4) geologia croatica 66/1geologia croatica 44 which he named global meteoric water line (gmwl). the gmwl is calculated for the mean ratios of oxygen and hydrogen isotopes from precipitation around the world. however, the oxygen and hydrogen isotope ratios of some regions can differ from the global ones due to different meteorological conditions in the region. in this case, the local meteoric water line (lmwl) can be calculated. the physico-chemical indicators which were continuously collected during fieldwork, as well as hydrochemical measurements, were geochemically modelled using the net path computer programme and statistical multivariate factor analysis using the statistica software package. netpath was developed by plummer et al. (1994) from the usgs and is based on the geochemical model of mass balance. it consists of a series of smaller programmes which, when put together, enable the input and management of chemical and isotope data from the analysed water. comparison of the determinants between samples was undertaken by applica tion of the r-mode factor analysis, using the statisti ca 6.0 programme package (1998), and showed geochemical processes were the dominating ones determining the che mical composition of the water,. factor analysis was performed on the following indicators: t, ph, ca2+, mg2+, nmg/nca, na+, k+, hco3 –, cl–, so4 2–, no3 –, po4 3–-p, sical, sidol, logpco2. 7. results and discussion 7.1. recession analyses the recession coefficients of the monitored springs were obtained using the „matching strip” method for the analysis of the falling limbs of the runoff hydrographs (fig. 3). since only the exponential regression model enables evaluation of the recession coefficient on which comparison of the properties of the aquifer are based,, this model was selected as being the most appropriate for comparison of the characteristics of the catchments of the monitored springs. for the discharge time series measured at majerovo vrilo, the most appropriate solution for the recession analysis was dividing the main recession curve into two parts at the point where the critical discharge rate was 6,4 m3/s. the value of the recession coefficient of the first part of the curve is α1 = 0,247 day–1, and the second α2 = 0,029 day–1. for other springs, division using three discharge micro-regimes was selected. at the klanac spring the discharge regime changes at the value of 4,13 m3/s. this implies that high waters are best described by the recession coefficient of α1 = 0,044. changes in the runoff regime also appear at the critical discharge value of 1.14 m3/s. hence the recession coefficient of α2 = 0,032 was calculated for the medium waters. the recession coefficient of low waters is α2 = 0,046. in the case of the pećina spring, the main recession curve was divided at the critical discharge value of 6.00 m3/s, and the high waters are best described by the recession coefficient of α =0,115. the medium waters recession coefficient value is α2 = 0,047 lasting until the critical discharge value of 0,65 m3/s. the value of the recession coefficient for low waters is α3 = 0,07. discharge of the aquifer at the pećina spring during the middle water regime is not uniform (fig. 3), suggesting that the regression model selected on the coefficient of determination is not significant. at the tonković spring, changes in the discharge regime appear at values of 4.20 m3/s and 2,70 m3/s. the recession coefficient defined by the automatic recession analysis is α1 = 0,023 for high waters, α2 = 0,014 for medium waters and α3 = 0,009 for low waters. as at the pećina spring, during the high water regime, significant differences can be determined in the drainage speed during individual recession periods at the tonković spring. this was the reason why it was not possible to analyse the high water recession curve with more certainty. figure 3: recession analyses at the observed springs. lukač reberski et al.: definition of the river gacka springs subcatchment areas on the basis of hydrogeological parameters geologia croatica 45 recession analysis (fig. 3, table 1) clearly showed that the pećina and majerovo vrilo springs have significant differences between the recession coefficients of the quick and the base flow, when compared to the klanac and tonković springs. the highest runoff differences between the base and quick flow occurs at the majerovo vrilo spring with the difference in the recession coefficient between the base and the quick flow being of one order of magnitude. furthermore, as seen on the recession curve graphs of the springs, the peći na and tonković springs have significant differences in the types of drainage of the fissured systems during different quick flow recession events. at the pećina spring, during individual recession periods, the runoff decreased from 5 m3/s to 1 m3/s in only 4 – 5 days, while during other recession periods for the same runoff more days are needed. at the tonković spring, significant differences in the discharge rates during different recession periods of the high water regimes can also be determined. while in some cases of recession, runoff decreases from 7 to 4 m3/s in only 2 days, sometimes 20 days were needed for the same decrease. this variation in the runoff properties at the same spring could be the result of: the varying intensity and spatial distribution of precipitation in the catchment, the land cover, differences in evapo transpiration rates, and the heterogeneity of the aquifer, which directly influences the dynamics of the runoff. at the klanac and majerovo vrilo springs, no such significant differences in the runoff during different recession events were determined. at the tonković spring the autocorrelation function (akf) has a steeper slope for the first 20 days. the memory effect, i.e. the average duration of the springs reaction to precipitation is 62 days. similarly, the slope of the function is steeper during the first 22 days at the klanac spring and the memory effect is 63 days. at the majerovo vrilo and pećina springs, the shape of the autocorrelation functions are somewhat different. at the majerovo vrilo spring the steepest slo pe of the function is in the first 4 days, while the response of the catchment, from which the spring is recharged, is 26 days. at the pećina spring the fast discharge lasts 9 days on average, and the memory effect of the spring is 33 days. steep slopes of the autocorrelation function (akf) indicate rapid infiltration of precipitation and faster drainage of the underground system through the well developed network of karst channels. its more gentle slopes reflect slower drainage of the fissured porosity aquifer area where discharge is similar to the intergranular aquifers. it was established, after the statistical analysis of the discharge time series using the autocorrelation method, that all four investigated springs drain water from aquifers with similar hydrogeological properties. this is evident from the similarities of their autocorrelation functions (afk) (fig. 4). nevertheless, at the pećina and majerovo vrilo springs the akf have a steeper slope at the beginning and the values of the memory effect are lower than at the klanac and tonković springs. this is the result of the better developed underground karst channel network of the pećina and majerovo vrilo aquifers, which is in accordance with the results of the recession analysis. when interpreting akf, it should be known that they relate to the average properties of the analyzed time series. from the cross-correlation functions (kkf) of discharge time series of the different springs, the connection and the interrelation of the springs can be recognized (fig. 5). symmetrical kkf values of all springs indicate that the springs are independent of each other and depend on some other variable. in this case it refers mostly to precipitation in the catch ment of the monitored springs, because their quantity and time and space distribution, together with the hydrogeological aquifer properties, influence the runoff dynamics at the springs. it is supposed, based on the high values of the maximum cross­correlation coefficients (max rxy), which range from 0,77 – 0,91, that all springs drain aquifers from catchments of similar hydrogeological characteristics and table 1: the values of the recession coefficients at observed springs. recession coefficient pećina majerovo vrelo tonković klanac α1 0.115 0.275 0.023 0.044 α2 0.047 0.029 0.014 0.032 α3 0.069 0.009 0.046 table 2: the values of basic statistical parameters for the flow rate. qmin (m3/s) qmax (m3/s) qx (m3/s) qσ (m3/s) cv (%) klanac 0.017 16.70 3.466 3.253 93.85 pećina 0.002 6.84 1.925 1.694 88.01 tonković 1.680 11.40 3.943 1.980 50.22 majerovo vrelo 1.000 21.03 3.264 2.263 69.32 in cases of extreme differences in the recession characteristics of the aquifer, it is not possible to determine the recession curve with a high value of the coefficient of determination r2. nevertheless, the „matching strip” method is still considered to be the more appropriate solution for the determination of the recession properties of the aquifer compared to analysing individual recession events. for the analysis of individual recession events, it is not possible to determine how much the runoff regimes of different recession events at the same spring differ from each other. 7.2 analysis of the complete hydrographs from the basic statistical water flow parameters presented in table 2 it can be seen that the mean discharge values (q) of the klanac, tonković and majerovo vrilo springs are very si­ milar, while at the pećina spring it is almost twice as low. the values of the variation coefficient (cv), which represents the ratio between the standard deviation (σ) and the mean value ( ) of the sample, indicate that the highest discharge variations occur at the klanac, and lowest at the tonković springs. geologia croatica 66/1geologia croatica 46 with a similar precipitation volume. the delayed response to rainfall of the klanac and tonković springs if compared to the majerovo vrilo spring, ranges from 24 – 36 hours. the delay at the pećina spring is between 12 – 24 hours. the majerovo vrilo spring reacts up to 12 hours prior to the pećina spring, the tonković spring up to 12 hours prior to the klanac spring. the highest cross­correlation coefficients are those of the klanac and tonković springs, with the lowest at pećina and majerovo vrilo, which is expected since these two springs have the most distant catchments. the maximum discharge and precipitation cross-correlation coefficients max rxy (fig. 6) are not high (0.3 – 0.46). the reason for the low values is that the discharge dynamics at the springs does not solely depend on the quantity of precipitation in the catchment. it also depends on the season, i.e. air temperature during precipitation, the vegetation and the hydrogeological properties, including the degree of karstification, the existence of cover deposits, their thickness and other factors. nevertheless, despite the low cross-correlation coefficients the connection between discharge and precipitation is clearly pronounced. at the pećina spring, the maximum cross­correlation coefficient was registered during the three day delay. this means that the average reaction delay of this spring is three days. at the majerovo vrilo spring, the reaction to precipitation is the same as for the pećina spring, but the max rxy is somewhat higher than the other springs. the cross­correlation coefficients of the klanac and tonković springs have two maxima which means that different precipitation events cause variation in delay. hence the klanac spring reacts in 4 to 10 days, and tonković spring 5 to 11 days after the onset of precipitation. various delay times at these springs could be the result of variation in infiltration of precipitation in the karst underground over both time and place in the catchment. rapid reaction of a spring to precipitation indicates fast infiltration in the epikarst zone and further into the underground channel system, which enables rapid transport. another reason could be a smaller catchment surface which makes the path the infiltrated water must travel from the surface to the spring significantly shorter. after a time period of 40 days the function gradually starts to grow again as seen on the cross-correlograms. this is in accordance with the autocorrelation functions of the springs, i.e. it is the result of repeated incoming water waves, especially in the wetter part of the year. all hydrograph statistical analysis, as well as recession hydrograph analysis used in this study, indicate faster reactions to rainfall by the majerovo vrilo and pećina compared to the tonković and klanac springs. this implies a better developed underground channel network of the aquifer systems of the majerovo vrilo and pećina springs. the klanac figure 4: autocorellograms of spring daily discharges. figure 5: cross-corellograms of discharge series. lukač reberski et al.: definition of the river gacka springs subcatchment areas on the basis of hydrogeological parameters geologia croatica 47 and tonković springs aquifer systems show better retention properties and lower permeability due to the network of smal ler fractures within the aquifer. 7.3 the isotopic composition of the waters the lmwl was calculated for the research area by mandić et al. (2008) (fig. 7) who emphasised that there is a need for several more years of measurements in order to determine a more precise value. the lmwl equation is as follows: dd = 6.8·d18o + 1.5 (5) the measured stable isotope oxygen-18 and deuterium values of the spring waters are scattered around the lmwl and gmwl values, clearly indicating that in the study area the groundwater is recharged from precipitation (fig. 7). it was shown by mandić et al. (2008) that the average deuterium excess in the investigated area is about 12 ‰. such values are evidence of the influence of the mediterranean type of climate, especially during the winter months, but the main influence is from the continental type of climate. no significant fluctuations in oxygen­18 values (fig. 8) were observed in the spring waters of the river gacka catchment which is in agreement with the observations of mandić et al. (2008). the lowest negative d18o values were mea sured at majerovo vrilo, followed by those at the tonko­ vić spring. the pećina spring has the highest positive values. these values imply the highest altitude of the recharge area occurs at the majerovo vrilo and the lowest at the pećina spring. for europe and africa, the δ18o isotope gradient ranges from –0.15 to –0.5 ‰ for every 100 m increase in altitude (clark & fritz, 1997). in order to calculate the altitude of the recharge area, the isotope gradient of –0,25 ‰ was selected and the δ18o values measured in spring and autumn, as suggested by clark & fritz (1997). the altitude differences obtained range from 140 to 260 m. clark & fritz, (1997), determined that the depletion for 18o varies between about –0.15 to –0.5 ‰ per 100 m rise in altitude. the calculated altitude values of the dominant recharge area of the springs are as follows: • majerovo vrilo – 1020 m a.s.l., • tonković – 760 m a.s.l. • pećina – 620 m a.s.l. 7.4. the quality of the spring waters the results of the measurements of the water quality indicators are given in table 3. based on their basic chemical composition the spring waters of majerovo vrilo belong to the ca­hco3 to camghco3-type of water, i.e. to the hydrochemical facies (fig. 9). spring waters of tonković, klanac and pećina belong to the ca-hco3 type of water. these water types are the result of the dissolution of carbonate minerals (calcite and dolomite) which are the main constituents of the catchment area of the springs. figure 6: crosscorellograms of springs which represent the relationship between rainfall and discharge. figure 7: the ratio of oxygen-18 and deuterium stable isotopes in spring waters of the gacka catchment. geologia croatica 66/1geologia croatica 48 the temperature of the spring waters, was measured periodically during the research period, and varies from 8.4 to 10.0 °c. this is generally in accordance with the mean annual air temperature of the recharge area of the spring. the lowest average measured temperatures were recorded at majerovo vrilo, which is in accordance with the data suggesting that this spring is recharged from the highest altitudes, where the temperatures are the lowest. temperatures measured at the tonković and pećina springs are also compatible with the calculated altitudes of their recharge area. the oxygen content measured in the spring waters, as well as the model determined carbonate saturation level, is advantageous, from the water quality protection standing point. a high oxygen concentration was measured in the waters which enables oxidation processes useful as water autopurification reactions. spring waters are mostly saturated with calcite, which enables deposition of any existing metals in the water due to their affinity with carbonates. hence, in saturated conditions these reactions could be initiated, which also has a water autopurification role. the measured nitrate concentrations are below the croatian drinking water standard. (official gazette no. 47/08) and range from 1.3 to 5.2 mg/l with small seasonal oscillations. the highest concentration was measured at the pećina spring (table 3) in the autumn and winter. this is the consequence of both anthropogenic influences and degradation of the plant material in the highly karstified aquifer of this spring. ammonium and orthophosphate concentrations are very low in all the springs and sometimes they are below the detection limit. figure 8: the distribution of stable isotope oxygen-18 in the spring waters. table 3: results of measurements of hydrochemical indicators. sp rin g t ec ph ca2+ mg2+ na+ k+ hco3 – cl– so4 2– no3 – po4 3–-p o2 (°c) (μs/cm) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) m aj er ov o vr el o min 8.8 307 7.22 54.8 2.1 0.8 0.4 204 1.3 3.4 2.1 0.02 8.2 max 9.6 461 7.69 88.4 26.5 4.5 0.9 312 4.0 5.8 4.3 0.04 11.7 avg 9.1 437 7.40 71.9 8.7 2.3 0.7 258 2.5 4.5 3.5 0.03 9.9 kl an ac min 9.0 440 7.11 62.9 4.4 1.0 0.4 235 1.7 4.3 1.6 0.01 7.2 max 10.0 493 7.63 138.0 13.8 4.6 1.1 428 4.9 11.4 3.7 0.05 14.4 avg 9.5 474 7.36 86.5 7.0 3.0 0.7 284 3.4 6.4 3.0 0.03 9.3 to nk ov ić min 9.5 473 7.10 62.8 4.3 2.5 0.4 235 2.6 4.1 1.3 0.01 6.1 max 9.9 532 7.60 124.0 14.6 6.9 1.0 398 14.1 12.9 3.9 0.04 11.7 avg 9.7 495 7.35 86.6 7.2 4.1 0.7 287 5.5 7.3 3.1 0.03 9.0 pe ći na min 8.4 442 6.95 60.4 3.0 2.2 0.5 218 2.9 2.9 2.2 0.01 7.2 max 9.9 503 7.96 138.0 13.4 6.2 1.0 426 5.0 10.9 5.2 0.05 11.2 avg 9.3 468 7.55 86.0 6.1 4.1 0.7 283 4.2 5.2 3.9 0.03 9.2 lukač reberski et al.: definition of the river gacka springs subcatchment areas on the basis of hydrogeological parameters geologia croatica 49 sulphate concentrations range from 3.4 – 12.9 mg/l and are below levels for the croatian drinking water standard (official gazette no. 47/08). concentrations of chloride range from 1.3 – 14.1 mg/l with the highest concentration being observed at the tonković spring in march (14.1 mg/l) and april (8.9 mg/l). furthermore, concentrations of chloride at other springs are higher in march and april, than during other months. these high concentrations are most like ly to be a consequence of de-icing of the roads, because the springs are located near them. waters of the river gacka springs are still characterised by their excellent quality and are classified as strategically important water reserves of the republic of croatia (official gazette no. 91/08). hence, it is important to monitor and to promptly react to existing and potential pollution sources in the catchment. taking into account previous hydrogeochemical studies carried out in this area (lukač re berski, 2008; lukač reberski et al., 2009), it is evident that, despite the good protection and quality, the analysed water quality indicators show an upward trend due to the anthropogenic influence in the spring catchments. 7.5. statistical analysis of the geochemical indicators of spring waters five factors were selected based on the results of the factor analysis i.e. the factor loadings (table 4). the first is the lithogenic factor and refers to the influence of the partial pres sure on the calcite and dolomite saturation indices, i.e. the influence on the dissolution/precipitation of limestone and dolomite. the second factor is also a lithogenic factor, and represents the influence of dolomite dissolution on the water chemistry. the third factor is anthropogenic; it shows the influence of the wash out of the terrain and epikarst zone on the chemistry of the water. the fourth factor is lithogenic and represents the dissolution of limestone. the fifth factor is anthropogenic and indicates the influence of salting of roads on the chemical composition of the water. 7.6. the calculations of mixing ratios mixing models for individual springs were provided using the netpath programme. the water ratios from the majerovo vrilo and tonković sprin catchments in the klanac spring were determined in order to establish if this spring shares the catchment area with the others. the water ratios vary depending on the hydrological conditions. during high and medium waters the klanac spring mostly shares the catchment area with the tonković spring (fig. 10). during low water periods it shares its catchment area equally with majerovo vrilo and the tonković springs. it should be noted that these values are valid for the time of sampling. for a more detailed analysis of their interrelationships samples should be collected on a daily basis throughout the hydrological year. 7.7. the subdivision of the catchment the catchment of the river gacka springs was divided into three subcatchments based on the results of the investigations, the interpretation of the lithological, structural and hydrogeological characteristics of the aquifer system and the hydrogeochemical properties of the spring waters, (fig. 11). the tonković and klanac springs, which are about 50 m away from each other, drain the same catchment as shown by the research results. hence, it was not possible to establish the groundwater divide between these two springs. the figure 9: piper diagram showing the hydrochemical facies of the observed springs (e.g. klan-11-08 means spring-month-year). table 4: factor loadings. factor score > 0,5 (varimax nom.) factor 1 fakcor 2 factor 3 factor 4 factor 5 t (°c) 0.00 –0.12 –0.63 –0.16 0.35 ph 0.17 0.09 0.12 –0.36 0.09 ca2+ (mg/l) 0.33 0.33 –0.02 0.83 0.22 mg2+ (mg/l) 0.07 –0.98 0.00 0.05 0.03 nmg/nca –0,04 –0.97 0.02 –0.17 –0.06 na+ (mg/l) 0.07 0.08 0.80 0.15 –0.01 k+ (mg/l) 0.25 0.05 0.13 –0.06 0.70 hco3 – (mg/l) 0.35 0.02 0.07 0.87 0.19 cl– (mg/l) –0.04 –0.01 –0.21 0.15 0.81 so4 2– (mg/l) –0.09 0.02 –0.80 –0.02 –0.37 no3 – (mg/l) 0.43 0.08 –0.18 –0.05 –0.16 po4 3–– p (mg/l) –0.08 0.00 0.13 0.21 0.38 si cal 0.90 0.06 0.16 0.25 0.17 si dol 0.90 –0.16 0.07 0.03 0.17 log pco2 –0.53 0.18 0.16 0.63 0.31 expl. var 2.42 2.12 1.86 2.18 1.82 prp. totl 0.16 0.14 0.12 0.15 0.12 geologia croatica 66/1geologia croatica 50 groundwater divide between the catchment of the pećina spring and the tonković and klanac springs is not a line, but represents a recharge zone which is determined between the se springs and is common to both catchments. most of the tonković and pećina springs catchment area drains the tonković spring. during high water levels a connection exists between the sink in kozjan with the pećina spring, as evidenced by tracing test results. furthermore, these test results indicate that the pećina spring has a larger catchment surface than expected based on the mean annual discharge values. considering the complex structural-tectonic relationships, which are a reflection of many phases of karstification and tectonism, particularly the neo tectonic dynamics (prelogović, 1989), it is difficult to determine the cause of this discrepan with a high degree of certainty. there are several possible explanations. one could be that during periods of heavy precipitation, the amount of rainfall exceeds the infiltration rate and the water level rises in the epikarst figure 11: river gacka springs subcatchment areas. 1-subcatchment areas: a majerovo vrilo, b tonković and klanac springs, c pećina spring, 2-common catchment area of adjacent subcatchments, 3-spring, 4-assumed groundwater flow direction, 5-gacka springs catchment groundwater divide, 6-approximate divide of common areas. figure 10: plot of the calculated mixing ratios of waters from the tonković and majerovo vrilo springs in the water from klanac spring. lukač reberski et al.: definition of the river gacka springs subcatchment areas on the basis of hydrogeological parameters geologia croatica 51 zone. this causes water overflow into the preferred flows near the surface, and possibly establishing a connection with the pećina spring, probably due to the infiltration through the shallower parts of the aquifer. another reason could be water flowing over a supposed hydrogeological barrier in the spring area during high waters. furthermore, underground discharge at the pećina spring is not excluded due to the fractured nature of the area surrounding the spring. this could be the case especially during low waters and could occur without any obvious surface runoff. in that case a larger catch ment surface is drained without any visible evidence on the surface. this could also be in accordance with the recently postulated theory (bonacci & andrić, 2008) which assumed that part of the waters of the river lika disappears and flows underground to the river gacka catchment, draining downstream in the pećina spring. three permanent springs are located downstream of the tonković spring: jaz, marusino vrilo and graba. they are characterised by small fluctuations in discharge under different hydrological conditions which indicate the existence of a barrier in their hinterland which slows down the groundwater and prevents significant water level fluctuations. a common zone was also defined between the majerovo vrilo catchment and the klanac and tonković springs. water tracings performed in vrhovinsko polje and at trnavac confirmed an underground connection common to both catch ments. furthermore, the hydrogeochemical mixing model showed that during high water levels the groundwater flows to the klanac spring from the same part of the catchment as to the tonković spring. under low water conditions, at the klanac spring there is an increased ratio of groundwater from the majerovo vrilo subcatchment. this is probably due to hydraulic conditions which prevent water recharge from the majerovo vrilo catchment during the high water regime. when the water level drops, water recharge from majerovo vrilo (fig. 12) is enabled. it is supposed that the water from the klanac catchment does not discharge towards the majerovo vrilo. 8. conclusion applied research techniques have enabled the recognition of subcatchments in, parts of the large karst aquifer system of the river gacka springs and the determination of their dynamic characteristics, as well as their interference. all the former hydrological analyses were performed based on hydrological da measured only on the river gacka profiles. such data were referred to the entire system, while the characteristics of certain parts of the catchment still remain unknown. therefore, in the cases of such large catchment areas, it is very useful to divide it into smaller units or subcatchments. results presented here show that there are significant differences in hydrogeological characteristics of individual parts of the large river gacka springs catchment area. based on interpretation of the lithological and structural-tectonic characteristics of the area, the tracing test data, and the applied research methods, the river gacka catchment is divided into three subcatchments: the majerovo vrilo, the tonković and klanac, and the pećine subcatchments. the boundaries between them are not presented as lines, but were determin ed as zones which are common to the neighbouring subcatchments (fig. 11). statistical analysis, analyses of the recession parts of the hydrograph, together with hydrogeochemical analyses, all indicate a better development of the groundwater flow paths of the aquifer systems in the majerovo vrilo and pećina springs catchments when compared to the tonković and klanac springs. this is the reason why the majerovo vrilo and pećina spring catchments are more sensitive to pollution. due to their well developed network of underground water flow and the short subsurface residence time of the water, they have a low water autopurification capacity. the tonković spring during the quick flows, showed significant variation in drainage during different recession events, as observed from recession analysis. this led to the conclusion that parts of this subcatchment are even more sensitive to pollution. the autocorrelati and cross-correlation time series analysis and the matching strip method are very useful methods for the hydrogeological research of karst aquifers. they enable collection of data regarding the average aquifer characteristics which can be used f interpretation of the hydrogeological properties of the catchment, such as the structural properties, type of porosity, development of the channel network, dynamics of the aquifer system, sensitivity to pollufigure 12: a conceptual model of the river gacka springs catchment area. geologia croatica 66/1geologia croatica 52 tion and others. analysis of the recession hydrograph using the matching strip method proved to be very useful because, in addition to calculation of the recession coefficient, the diagram can be used to establish the time period of various recession events, since all recession events of the time series are presented on the diagram. hence, such recession analysis is more reliable than cases where several recession events are considered individually. the water of the river gacka springs is still of excellent quality. hydrogeochemical investigations imply a trend of growing concentrations of anthropogenic indicators (nitrates, orthophosphates, sulphates and chlorides) in the spring’s catch ments. furthermore, the dominant processes which influence the composition of the spring waters were determin ed, together with the average recharge altitudes of the springs, and using a geochemical mixing model, the interference between the catchments was also established. results presented here point out the necessity for a multidisciplinary research approach, especially in order to determine the hydrogeological characteristics of complex aquifer systems like the river gacka springs catchment. due to the high importance of this catchment, which was proclaimed to be an area of strategic drinking water reserves for the republic of croatia, the collected data are useful for all future development plans, both for groundwater exploitation as well as for protection from possible contamination. references bahun, s. (1974): tektogeneza velebita i postanak jelar naslaga [the tectogenesis of the mt. velebit and the formation of jelar deposits – in croatian].– geol. vjesnik, 27, 35–51. bahun, s. & fritz, f. (1975): hidrogeološke specifičnosti jelarnaslaga [hydrogeological specificities of the jelar breccias – in croatian].– geol. vjesnik, 28, 345–355. bakalowicz, m. (2005): karst groundwater: a challenge for new resources.– hydrogeology journal 13, 148–160. doi:10.1007/ s10040 -004-0402-9. biondić, r., biondić, b. & meaški, h. (2010): novelacija granica zona sanitarne zaštite izvorišta gacke [gacka spring sanitary protection zone novelation – in croatian]. geotehnical faculty, university of zagreb, 115 p. bonacci, o. (1987): karst hydrology with special reference to the dinaric karst.– springer­verlag­berlin­heidelberg, 9/4, 328–338. bonacci, o. (1995): međuzavisnost geologije, hidrogeologije i hidrologije pri rješavanju hidrotehničkih problema. [the interdependence of geology, hydrogeology and hydrology in solving hydraulic proble – in croatian].– first croatian geological congress, book of proceedings, 1, 105–108. bonacci, o. & andrić, i. (2008): sinking karst rivers hydrology: case of the lika and gacka/croatia.– acta carsologica, 37/2, 185– 196. box, g.e.p. & jenkins, g.m. (1974): time series analysis: forecasting and control.–holden day, san francisco, 575 p. clark, i. & fritz, p. (1997): environmental isotopes in hydrogeology.– crc press, new york, 20, 174–188. craig, h. (1961): isotope variations in meteoric waters.– science, 133, 1702–1703. davis, j.c. (2002): statistics and data analysis in geology. cansas geo lo gical survey.– the university of cansas, third edition, usa, 638 p. dewandel, b., lachassagneb, p., bakalowicz, m., wengb, p. & al-malki, a. (2003): evaluation of aquifer thickness by ana lys ing recession hydrographs. application to the evaluation oman ophiolite hard­rock aquifer.– j. hydrol., 274, 248–269. doi: 10.1016/s0022-1694(02)00418-3. doctor, d. h., lojen, s. & horvat, m. (2000): a stable isotope investigation of the classical karst aquifer: evaluating karst groundwater components for water quality preservation.– acta carsologica, 29/1, 5, 79–92. eisenlohr, l., bouzelboudjen, m., kiraly, l. & rossier, y. (1997): numerical versus statistical modelling of natural respon­ se of a karst hydrogeological system.– j. hydrol. 202, 244–262. fiorillo, f. & doglioni, a. (2010): the relation between karst spring discharge and rainfall by cross-correlation analysis (campania, southern italy).– hydrogeology journal, 18/8, 1881–1895. doi:10.1007/ s10040-010-0666-1. friedman, i. (1953): deuterium content of natural waters and other substances.– geochim. et. cosmochim. acta, 4, 89–103. gajić­čapka, m., perćec tadić, m. & patarčić, m. (2003): digitalna godišnja oborinska karta hrvatske. [a digital annual precipitation map of croatia – in croatian] hrvatski meteorološki ča­ so pis (croatian meteorological journal), 38, 21–33. grasso, d.a. & jeannin, p-y. (1994): etude critique des méthodes d’analyse de la réponse globale des systèmes karstiques. application au site de bure (ju, suisse).– bulletin d’hydrogéologie de l’uni versité de neuchâtel, 13, 87–113. kendall, c. & mcdonnell, j. j. (1998): isotope tracers in catchment hydrology.–elsevier science b.v., amsterdam, 839 p. krešić, n. (1997): quantitative solutions in hydrogeology and groundwater modeling.–lewis publishers, new york, 461 p. larocque, m., mangin, a., razack, m. & banton, o. (1997): contribution of correlation and spectral analyses to the regional stu dy of a large karst aquifer (charente, france).– j. hydrol., 205, 217–231. doi: 10.1016/s0022­1694(97)00155­8. larocque, m., banton, o. & razack, m. (2000): transient sta­ te history matching of a karst aquifer ground water flow model.– ground water, 38/6, 939–946. lukač reberski, j. (2008): hidrogeološka i hidrogeokemijska osnova za defi niranje slijeva gacke i zaštita njenog izvorišta [hydro geological and hydrogeochemical basis for the catchment area defi ni­ tion: river gacka springs catchment area – in croatian].– unpubl. master’s thesis. rudarsko­geološko­naftni fakultet, sveuči li šte u zagrebu (faculty of mining, geology and petroleum en gi neer ing, university of zagreb), 118 p. lukač reberski, j., kapelj, s. & terzić, j. (2009): an estimation of groundwater type and origin of the complex karst catchment using hydrological and hydrogeochemical parameters: a case study of the river gacka springs.– geol. croat., 62/3, 157–178, doi: 10.4154/ gc.2009.15. lukač reberski, j. (2011): određivanje podsljevova izvorišta rijeke gacke na osnovi hidrogeoloških parametara [definition of the river gacka springs subcatchment areas on the basis of hydrogeological parametars – in croatian].– unpubl. doctoral thesis. rudarsko­ geološko­naftni fakultet, sveučilište u zagrebu (faculty of mining, geology and petroleum engineering, university of zagreb), 158 p. mandić, m., bojić, d., roller­lutz, z., lutz, h. & bronić krajcar, i. (2008): note on the spring region of gacka river (croatia).– isotop. envir. health studies, 44/2, 201–208. doi:10.1080/ 10256010802066364. mangin, a. (1981): utilisation des analyses corré1atoire et spectrale dans l’approche des systémes hydrologiques.– computers rendues acad. sci. paris, 293, 401–404. lukač reberski et al.: definition of the river gacka springs subcatchment areas on the basis of hydrogeological parameters geologia croatica 53 mangin, a. (1984): pour une meilleure connaissance des systemes hydrologiques a partir des analyses correlatoire et spectrale.– j. hydrol. 67, 25–43. official gazette no. 91 (2008): strategija upravljanja vodama [water management strategy – in croatian]. official gazette no. 47 (2008): pravilnik o zdravstvenoj isprav­ nosti vode za piće [drinking water regulations – in croatian]. padilla, a., pulido­bosch, a. & mangin, a. (1994 relative importance of basefl and quickfl ow from hydrographs of karst spring.– ground water, 32/2, 267–277. panagopoulos, g. & lambrakis, n. (2006): the contribution of time series analysis to the study of the hydrodynamic characteristics of the karst systems: application on two typical karst aquifers of greece (trifilia, almyros crete).– j. hydrol., 329/3–4, 368–376. doi: 10.1016/j.jhydrol.2006.02.023. parlov, j. (2010): identifikacija parametara za modeliranje toka pod­ zemne vode glavnih izvora u porječju mirne [identification of parameters used for groundwater modeling of major springs in the mirna river valley – in croatian].– unpubl. doctoral thesis. ru­ dar sko­geološko­naftni fakultet, sveučilište u zagrebu (faculty of mining, geology and petroleum engineering, university of zagreb), 111 p. pavičić, a., kapelj, s. & lukač, j. (2003): the influence of the highway on the protected spring of gacka river.– rmz – materials and geoenvironment, 50/1, 289–292. plummer, l.n., prestemon, e.c. & parkhurst, d.l. (1994): an interactive code (netpath) for modelling net geochemical reac tions alog a flow path, version 2.0, usgs.– water­resources investigations report 94–4169, reston, virginia. posavec, k., bačani, a. & nakić, z. (2006): a visual basic spread­ sheet macro for recession curve analysis.– ground water, 44/5, 764–767. doi: 10.1111/j.1745­6584.2006.00226.x. posavec, k., parlov, j. & nakić, z. (2010): fully automated objec tive-based method for master recession curve separation.– ground water, 48/4, 598–603. doi: 10.1111/j.1745­6584.2009. 00669.x. prelogović, e. (1989): neotektonski pokreti u području sjevernog velebita i dijela like [neotectonic movements in northern velebit and part of lika – in croatian]. geol. vjesnik, 42, 133–147. riggs, h.c. (1968): techniques of water-resources investigations of the united states geological survey, chapter a1, some statistical tools in hydrology. book 4, 39 p. stroj, a. (2010): podzemni tokovi u zaleđu krških priobalnih izvora na području velebitskog kanala [underground water flows in the hinterland of the velebit channel coastal karst springs – in croatian]. unpubl. doctoral thesis. rudarsko­geološko­naftni fakultet, sve­ učilište u zagrebu (faculty of mining, geology and petroleum engineering, university of zagreb), 259 p. tallaksen, l.m. (1995): a review of baseflow recession analysis.– j. hydrol., 165/1–4, 349–370. doi: 10.1016/0022­1694(95)92779­d. terzić, j., stroj, a. & frangen, t. (2011): hydrogeologic investigation of karst system properties by common use of diverse methods: a case study of lička jesenica springs in dinaric karst of croa­ tia.– hydrological processes. doi:10.1002/hyp.91 tomasko, d., fisher, a., williams, g. p. & pentecost, e.d. (2001): a statistical study of the hydrological character of the edwards aquifer.– argonne national laboratory, university of chicago for the u.s. department of energy, 34 p. doi:10.1061/40856(200)149. vandenschricka, g., van wesemaela, b., frota, e., pulido­bosch, a., molinab, l., stievenardc, m. & sou­ chezd, r. (2002): using stable isotope analysis (δd–δ18o) to characterise the regional hydrology of the sierra de gador, south east spain. – j. hydrol., 265, 43–55. doi: 10.1016/s0022­1694(02)00097­5. vlahović, i., tišljar, j. & velić, i. (2009): tercijarne karbonatne breče (paleogen­neogen­ pg, ng) [tertiary carbonate breccia, pgng – in croatian]. – in: velić, i. & vlahović, i. (2009): tumač geološke karte republike hrvatske 1:300000 [explanatory notes of the geological map of the republic of croatia in 1:300.000 scale]. croatian geological survey, 141 p. zaninović, k., srnec, l., perčec­tadić, m. (2004): digitalna godišnja temperaturna karta hrvatske [a digital annual temperature map of croatia – in croatian].– hrvatski meteorološki časopis (croatian meteorological journal), zagreb, 39, 51–58. žugaj, r. (2000): hidrologija [hydrology – in croatian].– rudarskogeološko­naftni fakultet, sveučilište u zagrebu (faculty of mining, geology and petroleum engineering, university of zagreb), 407 p. manuscript received october 09, 2012 revised manuscript accepted november 27, 2012 available online february 28, 2013 geologia croatica 66/1geologia croatica 54 www.geologia-croatica.hr abstract the ljubija ore deposits are the loci typici of siderite-barite-polysulphide deposits within the inner dinarides, gemerides and eastern alps. numerous sites of ore outcrops, smaller or larger ore bodies of mineralization, consisting of fe carbonates, sulphides, barite and fluorite are scattered over an area of 150 square km. the half billion tons of iron ore resources occur as replacement in dolostones and limestones, and as open-space fillings (veins, veinlets) in phyllites and sandstones. the genesis of the ljubija ore deposits has been explained as (i) syngenetic sedimentary-exhalative, (ii) hydrothermal-metasomatic in middle triassic time or (iii) hydrothermal replacement of sedimentary carbonates in permian time. basically two alternatives variscan or alpine metallogeny, frame the time of genesis from the middle carboniferous to the middle triassic. genetic interpretation of the ljubija ore deposits required convincing arguments based on recent achievements of plate tectonics. this contribution presents a set of new data on ore petrology, geochemistry, geolo gy and time of formation. the ljubija ore field could justifiably be termed the “ljubija geothermal field”, due to its areal extent and the thermal characteristics of numerous ore deposits and occurrences within the sana-una palaeozoic terrain. the ljubija geothermal field marks the first signs of thermal instability of pangea, revealing its breakdown along the deep fractures and heralding incipient intracontinental rifting, the first phase of the new alpine wilson cycle. the research reveals novel data on the p-t-x characteristics of ore forming fluids (microthermometry, ion chromatography, raman spectrometry), sulphur isotopes, maturity of organic matter by vitrinite reflection, and age determination by 40ar/39ar and k-ar methods. it adopts argumentatively all the estimated research parameters that constrain a justified genetic model. keywords: siderite-barite-polysulphide deposits, dinarides, ljubija, permian, zebra texture siderite, early intracontinental rifting, pangea break-up, geothermometry, geochronology. article history: received december 07, 2015 revised and accepted january 26, 2016 avaliable online february 29, 2016 1. introduction the ljubija ore deposits are located in northwest bosnia and herzegovina (44.55˚n, 16.3˚e; fig. 1), at the margin of the mesozoic carbonate platform, within the sana-una river palaeo zoic terrain, a part of the inner dinarides. numerous sites of ore outcrops represent smaller or larger bodies of mineralization, consisting of fe carbonate, sulphide minerals, barite and fluorite over an area of 150 square km. according to written documents, iron ore excavation in this area began in the years before christ. the first miners were phoenicians and illyrians. romans excavated and smelted iron ore for over 400 years in ljubija and they transported iron bars by road and the sana, una, sava, and danube rivers to places for further processing. in the middle ages, iron ore was smelted by the turks, as confirmed by the remains of primitive smelting plants in this area. in 1916, during world war i., modern mining of iron was started by the austro-hungarian monarchy and the production of iron ore has been ongoing for 99 years intermittently under the changing geopolitical divisions in this part of the balkans. the potential reserves of iron ore have been estimated at 500 million tonnes with an average fe content of 40-49 %. there are two types of iron ore, fe-carbonates, siderites and ankerites, and secondary oxide ores with limonite, in proportions of approx. 1:1 (cvijić, 2004). modern industrial mining in the ljubija ore field (adamuša ore deposit) began however, as a lead-zinc mine, and was temporarily aimed at mining barite and fluorite as well (cvijić, 2001; cvijić, 2004; grubić & cvijić, 2003). the ljubija ore field includes four opencast mines (adamuša, tomašica, omarska, and vidrenjak) in an area of about 120 km2. besides iron, several other commodities such as zinc, lead, barite, and fluorite were also exploited. the siderite ore occurs as a replacement in dolostones and limestones, and as open-space fillings (veins, veinlets) in phy3-30 26 figs. 2 tabs. doi: 10.4154/gc.2016.02 the ljubija geothermal field: a herald of the pangea break-up (nw bosnia and herzegovina) ladislav a. palinkaš1, sibila borojević šoštarić2, sabina strmić palinkaš3, walter prochaska4, zoltan pécskay5, franz neubauer6 and jorge e. spangenberg7 1university of zagreb, faculty of science, institute of mineralogy and petrology, horvatovac 95, hr-10000, zagreb, croatia (corresponding author: lpalinkas@geol.pmf.hr, phone: ++385 1 3361189) 2university of zagreb, faculty of mining, geology and petroleum engineering, department of mineralogy, petrology and mineral resources, pierottijeva 6, zagreb, croatia 3university of tromsø, faculty of science and technology, department of geology, dramsvegen 201, n-9037 tromsø, norway 4institute für geowissenschaften, montanuniversität, peter-tunner-strasse, a-8700, leoben, austria 5hungarian academy of sciences, institute of nuclear research, bém tér 18/c, h-4001, debrecen, hungary 6university of salzburg, department of geography and geology, hellbruner str. 34, a-5020, salzburg, austria 7institute of earth surface dynamics, bâtiment geopolis, ch-1015 lausanne, switzerland 4 vol. 69/1 llites and sandstones, with rare chalcopyrite and pyrite. the replacement ore has occasionally a zebra texture, with rhythmic banding of dark fine-grained and light sparry siderite, galena, sphalerite and quartz as open-space fillings. large accumulation of limonite occurs as a secondary ore, named „brand“. the genesis of the ljubija ore deposits has been explained by a few streams of thinking, (i) as a syngenetic sedimentaryexhalative, or as washouts of lateritic crusts in the sedimentary basin from a dry land area in carboniferous time (jurković, 1961; jurić, 1971; šarac, 1981), as (ii) of hydrothermal-metasomatic origin in middle triassic time (cissarz, 1951; janković, 1977), or as (iii) a hydrothermal replacement of sedimentary carbonates in permian time, recognized by katzer (1925); and advocated by palinkaš (1988; 1990), palinkaš et al. (2003b) and coworkers borojević šoštarić (2004), strmić palinkaš (2004), and strmić palinkaš et al. (2009). the ljubija deposits are the loci typici of the siderite-baritepolysulfide deposits within the inner dinarides, gemerides and eastern alps. previous studies connected the formation of the deposits either to the variscan or to the alpine metallogenesis and considered the middle carboniferous or middle triassic time of formation, respectively. however, the application of modern plate tectonic aspects of ore genesis is necessary for clarifying these controversial views on the origon of the mineralisation. variscan or alpine metallogeny frame the time of genesis from the middle carboniferous to the middle triassic. genetic interpretation of the ljubija ore deposits required, however, convincing arguments based on the recent achievements of plate tectonics. a basic framework of wilson cycles has been successfully established but difficulties have arisen from unresolved problems such as the time and space boundary between variscan and alpine tectogenesis. it was a source of ambiguity in the fundamental research of ljubija ore genesis. a proper genetic model depends substantially on understanding of the geological evolution of the dinarides. this contribution presents a set of new data on ore petrology, geochemistry and geology of the ljubija ore field, or justifiably termed the „ljubija geothermal field“ in this wider sense of meaning, due to its areal extent and thermal characteristics of numerous ore deposits and occurrences within it. this paper presents new data on the p-t-x characteristics of ore forming fluids (microthermometry, ionic chromatography, laser raman spectrometry), sulphur isotopes, maturity of organic matter by vitrinite reflection, and age determination by 40ar/39ar and k/ar methods. it adopts argumentatively all the estimated research parameters which constrain a justified genetic model. figure 1. geological map of the northwestern and central dinarides with the position of the siderite-barite-polysulphide deposits within the upper palaeozoic formation of the inner dinarides, ljubija ore field, trgovska gora, petrova gora, samoborska gora, bistra medvednica mts. (accommodated on the map after pamić et al., 1998). (1) palaeogene-neogene overstep sequences (2) palaeogene metamorphics and granitoids, (3) upper cretaceous and palaeogene flysch, (4) ophiolites, mostly mélange (5) jurassiccretaceous sequences (6) adriatic-dinaridic carbonate platform, (7) allochthonous triassic sequences, (8) allochthonous palaeozoic sequences and rhyolites, (9) palaeozoic hercynian metamorphic rocks and granitoids (10) faults, (11) nappe, (12) reverse faults, i outer dinarides, ia sava nappe, ii inner dinarides, iia pannonian nappe, iib durmitor nappe, iii pannonian basin, iv zagorje-midtransdanubian zone, v eastern alps. large faults: pl periadriatic, zz zagreb-zemplin. 5 palinkaš et al.: the ljubija geothermal field: a herald of the pangea break-up (nw bosnia and herzegovina) 2. summary of previous studies on the geology and origin of the ljubija ore deposits the first description of the mineralization in the ljubija basin came from katzer (1910). he recognized the relationship between the carboniferous limestone and siderite mineralization as a reaction contact, which was defined more precisely as a result of metasomatism, in his later work (katzer, 1925). thermal water enriched in iron bicarbonate, deposited siderite into the crevices of schists and limestones in the form of siderite veins with some sulphides and quartz. the solutions circulating through the networks of interconnected fractures within schists and limestone filled them with siderite. simultaneously, solutions caused metasomatism of the limestones into siderite and more distantly in fissures as ankerite. later tectonics cut deposits into blocks and displaced them, into the present geological structure. the only exception, suggesting syngenetic formation, was in krivaja ore occurrences, in the tomašica district. cissarz (1951) described the ljubija mineral deposits as hydrothermal deposits of paleozoic age and related them to deep magmatism. all these descriptions are a short transposition of katzer’s genuine obervations and interpretations. nöth (1952) supposed an intrusive-hydrothermal origin and upper palaeozoic age for the siderite veins and irregular ore bodies. ramović (1957) distinguished three types of mineral deposits in the ljubija area: (i) siderite veins hosted by palaeozoic schists and related to metasomatism of limestones intercalated with smaller or larger quantities of clastic material, (ii) metasomatic ore bodies hosted by palaeozoic limestones and (iii) secondary deposits formed by weathering. jurković (1961) described ljubija as marine sedimentary deposits of upper carboniferous age. the fe carbonates, siderite and ankerite, were deposited as mud, together with some contributory clastic detritus, with irregular sedimentary proportions. iron carbonates were cryptocrystalline and present-day textures were recrystallized through diagenetic processes. jurić (1971) supported a synsedimentary origin of the ljubija mineral deposits. janković (1987) emphasized the importance of permotriassic intracontinental rifting, with a magmatic paroxysm in the middle triassic. this is also the period when volcano-sedimentary deposits, skarns, massive sulphides, mercury deposits, bedded ferromanganese oxides, and mvt deposits were formed in the dinarides. there is no distinction, however, between permian early intracontinental rifting and triassic advanced rifting stages, so the ljubija deposits remain in the vast group of triassic deposits. their subterrestrial nature and lack of contemporaneous magmatism in the area did not attract attention as an argument for genetic modelling and discrimination from other triassic deposits. palinkaš et al. (1985, 1988, 1990, 2010) applied a wide spectrum of analytical methods to the siderite-barite-sulphides mineral deposits hosted by upper palaeozoic sedimentary complexes of the inner dinarides. special attention was paid to the ljubija ore deposits. on the basis of fluid inclusion studi es in quartz from three distinctive ore textures, e.g. dark massive siderite, zebra texture with dark and light siderite bands, and siderite veins in phyllites and meta-sandstones, the deposits were unambiguously ascertained to be hydrothermal in nature. boiling of ore forming fluids was recognised in the žune-dolinac barite-fluorite ore body in the ljubija ore field. it was used to reconstruct the depth of ore forming processes within one of numerous barite occurrences. applied hydrostatic pressure determines variable depths of formation around 100-200 m. based on the plumbotectonic modeling, palinkaš (1985), suggested a new genetic model with a subterrestrial, hydrothermal convection cell and suggested the permian as the formation time, related to the early intracontinental rifting. the model leaned on the contemporary plate tectonic reconstructions by channel et al. (1979), horvath & d’argenio (1985), kovacs (1984), and pamić (1984), which convincingly linked similar deposits along the present day edge of the carbonate platform, trgovska gora, petrova gora, samoborska gora (croatia; palinkaš et al., 2000, 2001, 2003a, 2010; borojević šoštarić et al. (2004, 2009), rudabanya (hungary; szakall, 2001), rudnyani (slovakia, hurai et al., 2002) and erzberg (austria, prochaska et al., 1997) with an equivalent genesis in time and space. borojević šoštarić (2004), on the basis of fluid inclusion studies, vitrinite reflection, 40ar/39ar and k-ar dating supported a genetic model based on the subterrestrial hydrothermal convection cell and permian time of mineralisation related to early intracontinental rifting events. strmić palinkaš et al. (2009) presented an extensive geochemical study of the ore and host rocks and made a significant breakthrough in the interpretation and confirmation of the previous studies. the study was focused on the stable isotope composition of barren and mineralized carbonates (δ13c and δ18o values), quartz (δ18o), and sulphur minerals (δ34s), the distribution of major and trace elements, including ree, in barren and mineralized carbonates and surrounding clastics, and organic geochemistry research (total organic carbon, hydrocarbons distribution, isotopic composition of individual alkanes (δ13c), and kerogen (δ13c, δ15n) of barren and mineralized samples. 3. geological setting 3.1. regional geological setting the orogenic belt of the dinarides stretches 700 km along the north-eastern margin of the adriatic microplates (dercourt et al., 1993). in the north, this highly complex folded, thrusted and imbricated belt merges with the southern alps and in the southeast it extends into the hellenides (pamić et al., 1998). the general strike of the folds, thrusts and knappes in the central dinarides is nw–se, and the transport direction is towards the sw. the main tectonstratigraphic units of the central dinarides display a regular zonal pattern from stable adria to tisia. the historical division to “external” and “internal” dinarides, predates the plate tectonic concept, but it is still useful to discriminate tectonostratigraphic elements belonging to the passive and active tethyan continental margins, respectively. the dinaridic palaeozoic complexes (pcs) occur in the exter6 vol. 69/1 nal and internal dinarides. the pcs in the external dinarides, close to or within the carbonate platform, acquired a comparatively autochthonous position relative to their mesozoic cover. within the sava knappe, pcs are disrupted and allochtonous. they can be correlated tectonostratigraphicaly with those in the southern alps, and could be related to the passive continental margin of gondwana. the palaeozoic formations within a carbonate platform or adjacent to it, were not affected by high grade metamorphism. the pcs in the sava knappe, including the sana-una pc, close to the ensialic tisia block, however, underwent very low and low-grade metamorphism. the dinaridic metallogenic province developed as a result of opening of the vardar and dinaridic branches of the neotethyan ocean and its closure by convergence of the african and eurasian plates. the northern boundary of the dinarides is related to the northern african margin (adria–apulia). the dinarides embrace well-developed and preserved tectonostratigraphic units related to the alpine wilson cycle, in contrast to the neighbouring alps where the indentation of adria obliterated or blurred their regular distribution as a result of intensive tectono-metamorphic events (fig. 1). the major stages of the cycle are: a) permian early intra-continental rifting, b) triassic advanced rifting, c) jurassic oceanization, d) cretaceous subduction, e) palaeogene collision; and f) late palaeogene/neogene post collision and extension followed by orogenic collapse. the metallogeny of the dinarides, based on the principles of plate tectonics, has been upgraded over recent decades. each stage creates characteristic ore deposits related to specific geological environments. thermal events in the stage of early intra-continental rifting were in response to the high heat flow caused by thermal doming and thinning of the continental crust. it generated numerous hydrothermal cells in the thick piles of the postvariscan overstep successions. in addition, the incipient magmatism penetrated the variscan basement of pangea (palinkaš et al., 2001; palinkaš et al., 2010; rottura et al., 1998). this stage produced numerous hydrothermal siderite-barite-polysulphide deposits, including the ljubija ore deposits. they are the loci typici among the other equivalent deposits within the dinarides, gemerides and eastern alps (fig. 1), discriminated distinctly from the deposits of the advanced rifting stage occurring in the middle triassic (janković, 1977, 1986; petraschek, 1977; pamić & jurković, 1997; heinrich & neubauer, 2002; jurković, 2003). 3.2. the sana-una palaeozoic terrane the sana-una pcs mostly consist of carboniferous flysch sequences (sensu karamata et al., 1997). the flysch is overlain by bedded limestones with conodonts of late viséan age. a new (“post-variscan”) sedimentary cycle started with the accumulation of shallow water limestones (stara rijeka formation) of bashkirian age, which rarely yield marine shallow water fossils and fusulinids. the overlying eljdište formation (sandy and marly limestones) includes a rich brachiopod fauna. in the una region, the blagaj formation, covering the carboniferous flysch, is an olistostromatic unit, termed “wild flysch“ sensu grubić et figure 2. a) geological map and b) stratigraphic column of the sana-una palaeozoic formation (after cvijić, 2004). 7 palinkaš et al.: the ljubija geothermal field: a herald of the pangea break-up (nw bosnia and herzegovina) al. (2000), with devonian, lower and middle carboniferous limestone clasts containing foraminifers, corals and conodonts, and is correlated with the “molasse” type ivovik formation from the autochthonous jadar block terrain. disconformities between the blagaj formation and the carboniferous flysch have not been proven. these sequences are covered by middle permian clastic sediments (red breccias and conglomerates, sandstones, shales and evaporites) followed by lower triassic formations (fig. 2) (protić et al., 2000; grubić & protić, 2003; krstić et al., 2005). 3.3. geology of the ore deposits the ljubija ore deposits are placed within the javorik flysch formation, which is well exposed within the adamuša and the tomašica opencast mines (grubić et al., 2000; grubić & cvijić, 2003). at adamuša, the upper part of the lower flysch horizon contains irregular limestone blocks (olistostromes). figure 4. a) zebra siderite comprises dark siderite and light sparry siderite bands. it contains cavities infilled with sparry ankerite, quartz, sulphides, represented mainly by galena and sphalerite (b) and alteration li-phyllosilicates (c), adamuša open-cast mine. figure 3. dark massive siderite and ankerite in contact with dark massive limestones, the tomašica open-cast mine. figure 5. a) siderite veins hosted by phyllites and metasandstones, adamuša open-cast mine. b) close lookup of the banded zebra texture, dark siderite, light siderite and the central white ankerite band. a b 8 vol. 69/1 stones, dolostones, fe-enriched limestones, dark grey massive ankerite, and dark grey massive siderite locally weathered to porous limonite. 3.4. ore mineralization the ljubija ore field comprises the large iron ore deposits of adamuša, tomašica, omarska, and vidrenjak, and a number of smaller ones. important reserves occur in the secondary haematite limonite ore, locally named “brand”, weathering products of carbonate ores. beside iron ores important commodities are barite and fluorite occurrences, mined in the past, scattered over the whole palaeozoic terrain. palinkaš (1988) recognized three major types of primary iron ore textures: (1) dark massive siderite and ankerite, (2) zebra siderite composed of dark massive and light sparry siderite bands, and (3) sparry siderite veins hosted by phyllites and metasandstones (figs. 3, 4, 5). a simplified stratigraphy for the paragenetic sequences of the ljubija deposits is shown in (fig. 6). dark grey massive siderite and ankerite occur as replacements within limestone and dolostone blocks. the contacts between fe carbonates and host carbonates are obscure. all carbonates mentioned above are dark grey in colour due to the presence of organic matter (strmić palinkaš et al., 2009). a few millimetre thick white calcite veins, cross-cut dark grey limestones and are more abundant near fe mineralisation. similar, siderite, quartz and white calcite veins locally intersect the dark grey siderite. white sparry ankerite rarely occurs at the contact with dark massive siderite. zebra siderite is characterized by the alternation of dark massive and light sparry siderite bands. cavities infilled with white sparry ankerite, quartz, sulphides, and secondary phyllosilicates are common. sparry yellowish to brownish-ochre siderite veins, thick a few decimetres, hosted by phyllites and metasandstones, represent the latest phase of mineralization. the contact between siderite and fine-grained clastics is marked by the presence of sulphides, mainly chalcopyrite. in the eastern part of the ljubija ore field, economically important quantities of galena, tetrahedrite, chalcopyrite, and sphalerite have been exploited in the past. barite and fluorite ores are present mainly as e–w oriented veins that cross-cut the palaeozoic dolostones. the žunedolinac vein type deposit was the object of this study, and was described by jeremić, 1958; (fig. 7). a barite vein is hosted by dolostone and phyllites, close to the scytian shales and sandstones. the vertical vein reaches 3-9 m in thickness. barite incorporates coarse fragments of the host rocks and fluorite and quartz accumulations close to the walls. the structure and texture of the vein bears some elements of hydraulic fracturing, an important prerequisite for boiling of hydothermal fluid, as recognized in the fluid inclusion studies. 4. analytical methods 4.1. microthermometric measurements microthermometric measurements were performed on double polished 0.3 to 0.5 mm thick quartz wafers and 0.05 to 0.1 mm thick fluorite wafers using a leitz-wetzlar microscope coupled with a chaixmeca cooling and heating stage, operating between -180 and +600°c. objective lenses p25/0.50 were used for figure 6. stratigraphic column of the adamuša open-cast (after grubić et al., 2000). side rite with a zebra texture and sparry ankerite occur mostly within the siderite-metaclastics horizon. the javorik flysch formation at the tomašica opencast mine is represented by six horizons. the siderite-limonite horizon contains dark-grey massive to yellowish coarse-grained siderite and gossan composed of porous limonite. the olistostrome horizon comprises a wide variety of carbonates including dark massive limestones, dolomitic lime9 palinkaš et al.: the ljubija geothermal field: a herald of the pangea break-up (nw bosnia and herzegovina) freezing and um 32/0.30 for heating runs. microthermometric measurements on 0.1-0.2 mm thick siderite wafers were carried out using a linkam thms 600 freezing-heating stage mounted on an olympus bx 51 microscope with 10x and 50x long-working distance lenses. pure h2o and h2o-co2 synthetic fluid inclusion standards (syn flinc) were used to calibrate the equipment. the precision of the systems was estimated at ±2°c for heating runs, and ±0.2°c in the temperature range between -60 and +10°c. fluid inclusions were classified according to the criteria summarised by roedder (1984) and shepherd et al. (1985). the salinity of aqueous inclusions was calculated by temperatures of ice and hydrohalite melting using the fluids computer program for nacl-cacl2 bearing aqueous solutions at low temperatures (bakker, 1999). calculations are based on purely empirical best-fits, with no fundamental thermodynamic modelling involved (naden, 1996). isochores were calculated by use of the computer program isoc (bakker, 2003) using the equation of state by zhang & frantz (1987) corrected for the volumetric properties of quartz (hosieni et al., 1985). the salinity of aqueous inclusions with the addition of co2 at the vapour phase is calculated according to collins (1979). fluid inclusions are measured in: (i) quartz from quartz veins within dark metasomatic siderite (adamuša locality), (ii) quartz and siderite from metasomatic zebra siderite (adamuša locality); (iii) quartz and siderite from vein-type siderite (adamuša locality), and (iv) fluorite from fluorite-barite vein (žunedolinac locality). 4.2. ionic chromatography, bulk crush-leach analysis bulk crush-leach analyses were performed by ion chromatography at montanuniversität leoben. leachates were prepared according to the technique modified after bottrell et al. (1988). a dionex dx-500 system was used for halogen analyses. cations were measured in the aliquots of the same solution using standard atomic absorption spectrometry. bulk fluid inclusion composition is analysed in: (i) 3 quartz, (ii) 6 siderite, (iii) a single ankerite and (iv) galena sample from metasomatic zebra siderite (adamuša locality); (v) 3 quartz, (vi) 4 siderite, (vii) 2 barite and (viii) 2 galena samples from vein-type siderite (adamuša locality); (ix) 2 dark host limestone; (x) a single bladed calcite (adamuša locality); (xi) 5 fluorite and (xii) 7 barite samples from fluorite-barite vein (žune-dolinac locality). equilibration temperature between ore forming fluids and the host rocks was calculated using the equation of can (2002), giggenbach (1988), fournier & truesdell (1973), and verma & santoyo (1997) for geothermometric pairs na/k, k/mg, na/k/ca and na/li. the evaporation trend of the sea water is taken from mccaffery et al. (1987), and permian and recent water from horita et al. (1991). 4.3. raman spectroscopy the dilor labram instrument equipped with double nd-yag 100 nw (532 nm) and hene (613 nm) lasers was used at the institute für geoswisssenschaften, mountainuniversität, leoben. the instrument is connected to an olympus bx-40 equipped with linkam thmsg 600 heating-freezing stage, ope rating between -180 and +600°c. data were analysed using labspec software. laser raman spectroscopy was performed on fluorite samples from fluorite-barite vein (žune-dolinac locality). 4.4. vitrinite reflection the analyses have been performed using a leitz-mpv3 microscope-photometer, in oil, under magnification of 500× at the organic geochemistry laboratory, ina oil company, zagreb. samples are powdered, treated with hcl (3 days) and hf (3 days), washed and dried. concentrated organic matter has been mixed with immersion oil and examined under the photometer. synthetic spinel (r = 0.42 %) and garnets (r = 0.82 %; r = 1.76 %) are used for calibration. mean random vitrinite reflectance (rm in %) shows a strong correlation (r2=0.7, n>600) with maximum burial temperature (tmax in °c). these data are modelled after berker & pawlewitz (1994) by the linear regression equation t = (lnro + 1.68)/0.0124, ro = degree of vitrinite reflectance. vitrinite reflection is determined on (i) 6 host limestone samples; (ii) host siltstones (iii) host sediment containing sulphides, and (iv) siderite samples from a metasomatic ore (all samples from tomašica locality). 4.5. sulphur isotopes sulphur isotope analyses of sulphides and sulphates selected exclusively from the primary ore samples not from the sulfides in the host rocks, were performed at the university of lausanne using a carlo erba 1108 elemental analyzer (ea) connected to a thermo fischer delta s irms (ea/irms). the sulphur isotope values are reported relative to a vienna-cañon diablo troilite standard (v-cdt). the reproducibility, assessed by replicate analyses of laboratory standards (pyrite, synthetic mercury sulphide, working; barium sulphate), was better than ±0.2‰ (strmić palinkaš et al., 2009). 4.6. geochronology k/ar age dating k/ar age dating of the whole rock samples, 21 samples of metaclastic rocks and 7 samples of volcanic rocks, are performed at the institute of nuclear physics, debrecen, hungary, after the procedure described by odin et al. (1982). figure 7. the cross-section of žune-dolinac barite-fluorite body. 10 vol. 69/1 figure 8. a) dark and light bands in the zebra texture (photomicrographs, crossed polars). the dark band consists of nonplanar, closely packed anhedral siderite crystals with curved, lobate and serrated boundaries. the light band is made of saddle siderite characterized by curved crystal faces or crystals with sectorial growth. the sweeping extinction indicates a warped crystal lattice. the saddle texture forms under hydrothermal conditions in the voids, between dark bands; b) the void-filling process starts with saddle siderite lining the walls and succeeded by minerals in the following order: ankerite, sulphides and quartz, not necessarily with the presence of all the successive members. the residual zones in microgeodes on the photomicrographs are lined with curved saddle siderite crystals and those with sectorial growth are filled with quartz, the object of fluid inclusion study; c) ankerite (blue-green) replaces micritic dark limestones (pinkish red) as a sharp ferritization front (crossed polars, the colour hues come from alizarin red-s and kferricyanide tests. detailed description of the staining method of warne, 1962); d) metasomatic replacement of late diagenetic dolomite by fe-carbonate. the late diagenetic unimodal, planar-e dolomite, is mimically replaced by non-planar, unimodal ankerite, with curved and serrated intercrystalline boundaries. the crystal boundaries of ankerite grains gradually fade into a shapeless mass of siderite (plain-polarized light), e) advancing sideritization front in the greywacke sandstone, with sparry siderite, develops an exotic aggregation of detrital grains. the virtual, quartz-like shape of the detrital aggregation is framed and constrained by sparry siderite crystal faces; f) an advancing sideritization front pervades greywacke sandstone forming fine grained sideritic cement. texturally immature greywacke contains poorly sorted, angular grains of quartz and lithic fragments mostly metamorphics, slates, cherts and quarzites, set in a compact clay-fine matrix and detrital carbonaceous matter. the greywacke sandstone and black shales, a part of the „wild flysch“, originated as a product of strong turbidity currents at the edges of the continental shelves. 11 palinkaš et al.: the ljubija geothermal field: a herald of the pangea break-up (nw bosnia and herzegovina) figure 9. a) siderite veins were formed in the late stage of mineralization in which ore bearing fluids, penetrated into the clastics, along brittle fractures and deposited sparry siderite in the open veins. while the quartz teeth grow inward from the vein walls, sulphides, pyrite, chalcopyrite and traces of galena and sphalerite fill open-spaces in the vein centre; b) void filling processes in the light band zebra siderite proceeds with increased concentration of metasomatically released ions, ca2+, mg2+, and silica leached from incorporated clay particles in dark bands. increased sulphur fugacity is marked by co-precipitation of finegrained pyrite and traces of galena as a veneer within sparry siderite, the major sulphide phase; c) and d) void-filling paragenesis in the light bands of the zebra siderite; e) the host rocks underwent pervasive sideritization followed by silicification, recognized by strain fringes and strain shadows around the pyrite crystals; f) hydraulic fracturing of galena by silica rich fluids is evidenced by jig-saw-fit texture with fragments stuck together by silica cement. absence of grain boundary migration and rotation, evidenced by near parallel cleavage among the galena grains, which already past static recrystallization (triplet junction), is a sign of low temperature recrystallization in the following mineralization history; g) penetrative fabrics might have been developed by crystallization pressure in veins, evidenced by stylolites between sparry siderite grains, or as low grade metamorphism in the presence of water when pressure solution was dominant (merino et al., 2006). 12 vol. 69/1 40ar/39ar analyses 40ar/39ar analyses were carried out at the argonaut laboratory of the division of general geology and geodynamics at the university of salzburg. a single white mica concentrate from vein-type siderite was irradiated in the mtakfki reactor (debrecen, hungary). 40ar/39ar analysis was carried out using a uhv ar-extraction line equipped with a combined merchantektm uv/ir laser ablation facility and a vg-isotechtm ng3600 mass spectrometer. isotopic ratios, ages and errors for individual steps are calculated following suggestions by mcdougall & harrison (1999) and using decay factors reported by steiger & jäger (1977). definition and calculation of plateau ages was carried out using isoplot/ex softwer (ludwig, 2001, 2005). 5. results 5.1. petrography transmitted and reflected light microscopy supports the genetic interpretation of the ore textures (figs. 8, 9). the three major type of textures are (i) dark grey massive siderite, (ii) zebra texture with dark and light siderite bands, and (iii) vein siderite. (i) dark massive siderite was formed by volume-pervolume replacement of dolostones and limestones by fe-saturated solution (fig. 3). metasomatizm is recongnized by the unimodal size of siderite grains, with nonplanar boundaries, non-mimical replacement of dolomite allochems, and traces of indigenous organic matter which still gives a dark colour to the bands. the nonplanar boundaries are characteristic of growth at elevated temperature and/or high supersaturation, as neomorphism of a precursor dolostone or limestone (fig. 8d) (sibley & gregg, 1987). (ii) formation of the zebra texture is a combination of two different processes, replacement as simultaneous solution and deposition of siderite, in the manner of atom-per-atom, expressed by reactions 1) and 2 ). 1) caco3 + fe2+ = feco3 + ca2+ δvreac = 22%, δg reac 500 = -27.95 kj log kreac 500 = 2.91, t = 500 k δḡreac 500 = -27.95 + 9.59log aca2+ 9.59log afe2+ 2) (ca,mg)co3 + 2fe2+ = 2 feco3 + ca2+ + mg2+ δvreac = -11% , δgr reac 500 = -43.7 kj log kreac 500 = 4.5, t = 500 k δḡreac 500 = 43.7 + 9.59 (log aca2+ + log amg2+) – 19.18 log afe2+ it is accompanied by a significant change of volume, δvreac %= -22% and -11%. a difference between the molar volume of siderite and precursor limestone/dolomite, leaves open space for sparry siderite in the zebra texture. replacement is sustained by infiltration of an iron rich hydrothermal fluid, rather than by restricted diffusion sensu korzhinskii (1968). the succeeding step was the crystallization of saddle style siderite in open voids from fe-impoverished and ca2+/mg2+enriched fluids. this highly variable concentration and composition of the fluid is a cause for the growth of curved crystal faces and sweeping extinction of saddle siderite (fig. 4a, 8b; 9d) (saerl, 1989): 3) fe2+ + co3 = = feco3 δg reac 500 = -12.26 kj log kreac 500 = 1.27, t = 500 k δḡreac 500 = -12.26 – 9.59 log afe2+ -9.59 log a co = this is a typical of open space filling processes identified by many vugs and cavities, coarsening of minerals from the walls of the voids to their centre, comb structure or interdigitated vuggy zone, and symmetrical banding. the void-filling process starts with saddle siderite, lining the walls and proceeds in the following sequential mineral order: ankerite, quartz and sulphides, not necessarily with the presence of all the successive members (fig. 9b, 9d). some thermodynamic consideration of the free energy change (δḡreac 500) at 500 k (227°c) confirms the prefe rence of reactions (1) and (2) during the early metasomatic phase, and the formation of dark bands. the increase of ca2+/mg2+ concentration increases δḡreac 500 and supports the tendency of reaction (3) to dominate during crystallization of light sparry siderite bands. the presence of co2 (recognized at the trace level by raman spectroscopy) is an irrelevant variable in the reactions (1) and (2) and equilibria is controlled by the fe2+/ ca2+mg2+ratio. reaction (3) proceeds under neutral and slightly alkaline conditions, buffered by carbonate host rocks and the dominant species are hco3 and co3 =, and fugacity of co2 is negligible. it is not the case in the silici clastic host rocks, during development of barite vein deposits, whereas liquid co2 also participated in the control of pressure and boiling (borojević šoštarić et al., 2009). (iii) siderite veins, another structural facet of the ores, were formed by mineralizing fluids, enriched in fe-bicarbonate ions by widespread collateral metasomatic reactions (fig.5). they penetrated into the shales, silts and sandstones, along planar discontinuities caused by fault slip events under brittle conditions and deposited sparry siderite in open veins with fuzzy boundaries (fig. 9e). the host rocks underwent pervasive sideritization during the mineralization phase followed by silicification, recognized by antitaxial strain fringes and strain shadows around the rigid pyrite porphyroblasts. characteristic dilatation sites were formed by silica rich fluids at low-temperature (200-300oc) and high fluid pressure (oliver & bons, 2001). enrichment of the silica component in the fluids came from the alteration of phyllosilicates and residual clay particles in the carbonate precursor. the best conduits of the fluids were dark seams, composed of organic detritus, phyllosilicates, and insoluble material, deformed around a rigid object, e.g. a corroded detrital quartz grain (fig. 9e). hydraulic fracturing of galena is another aspect of the high fluid pressure (fig. 9f). the galena triple-junction system, forms a hexagonal network of recrystallized grains, which underwent fracturing, sustaining a jig-saw-fit texture with fragments stuck together with silica cement (lower corner of fig. 9f). 3 13 palinkaš et al.: the ljubija geothermal field: a herald of the pangea break-up (nw bosnia and herzegovina) the quartz grain shows clear signs of dynamic recrystallization by development of subgrains and gradual bulging (stipp et al., 2002). beside fluid inclusion data, deformation lamellae in siderite crystals could be used as an approximate temperature gauge of vein formation. narrow straight twins (fig. 9e, type i, burkhard, 1993) indicate temperatures bellow 170oc. the tabular thick twins, which can be optically resolved (fig. 8c, type ii, ˃1µm, ferril et al., 2004), dominate above 200 oc and up to 300oc. penetrative fabrics which might be related to the crystallization pressure in veins, are evident by stylolites between sparry siderite grains (fig. 9g, merino et al., 2006). the siderite walls of the vein include quartz-comb textures grown inward, accompanied by pyrite, chalcopyrite, traces of galena and sphalerite (fig. 9a). chert and schist fragments in the greywacke are inherited porphyroclasts from the variscan high-grade metamorphic provenance, incorporated during the turbidite phase (fig. 8f). 5.2. fluid inclusion study fluid inclusion studies in quartz from quartz veins within the dark metasomatic siderite (adamuša locality) quartz veins are several mm to 10 cm thick containing milky white quartz. at several places open space cavities are found containing half-transparent idiomorphic quartz, several millimetres in size. fluid inclusion petrography shows the presence of primary and pseudosecondary liquid-rich inclusions of a uniform degree of fill. eutectic melting occurs at temperature ranges from -39.4 to -21.0ºc. ice melting in the temperature range from -23.9 to 1.5ºc shows salinities from 23.4 to 2.1 wt.% nacl equiv. homogenization by vapour disappearance occurs in a temperature range from 80 to 160ºc. fluid inclusion study in quartz from cavities within metasomatic zebra siderite (adamuša locality) the investigated quartz follows precipitation of light zebra siderite, and precedes the precipitation of sulphides (galena, sphalerite, chalcopyrite, pyrite) within the cavities. quartz crystals are idiomorphic, transparent up to 1 cm in size. they contain numerous fluid inclusions which are located within growth zones and classified as primary according to the criteria outlined by roedder (1982): type i; liquid-rich four phase, aqueous inclusions containing a halite daughter mineral, also sometimes contain an unknown anisotropic daughter mineral, (l+v+shal±sa); type ii; liquid-rich three phase aqueous inclusions, containing an unknown anisotropic daughter mineral (l+v±sa), high salinity; type iii; inclusions contain immiscible liquids (l1+l2). type iv; monophase liquid figure 10. fluid inclusions in quartz from void-fillings in the zebra siderite, and mesothermal siderite-quartz veins in the greywacke (ljubija/adamuša). a) „zebra siderite“: primary (l+v+shal), (l+v+sa) and (l+v) inclusions, type i and ii; b) array of primary inclusions (l+v), type ii with the same degree of filling; c) array of primary (l+v+shal) inclusions; d) primary (l+v) and (l+v+sa) inclusions, type ii; e) primary inclusions with immiscible fluids (l1+l2), type iii; f) primary inclusions (l+v+shal), type i. mesothermal sideritequartz veins: g) quartz with marked primary (p), pseudosecondary (ps) and secondary (s) inclusions; h) array of liquid inclusions, type iv; j) primary (l+v) and (l+v+sa) inclusions, type iii (see text). 14 vol. 69/1 inclusions, liquid inclusions containing a halite daughter mineral (l±v±shal) and (v); monophase gas inclusions (fig. 10). the study was focused on a primary assemblage of aqueous inclusions. within halite bearing inclusions eutectic melting occurs in a temperature range from -65.7º to -51.0ºc, followed by ice melting in the temperature range from -44.2º to -21.6ºc, and hydrohalite melting (transformation to halite) at a temperature range of -40.9º to +0.1 ºc. under metastable conditions, hydrohalite exists up to 22ºc in a few inclusions. in addition, several inclusions show melting of an unknown, optically isotropic phase at a temperature range from -35.0º to 36.1ºc. total homogenization occurs in the temperature range from 201ºc to 259 ºc, showing salinities from 35 to 39 wt.% nacl equiv. during homogenization, inclusions show different behaviours: (i) the disappearance of vapour follows the disappearance of halite; (ii) the disappearance of halite follows the disappearance of vapour, or (iii) halite and vapour disappear simultaneously. the case of simultaneous disappearance of vapour and halite occurs at temperature ranging from 220º to 259ºc. the existence of three and the disappearance of two phases (l+v+shal→l) in the nacl-h2o system (th total), is univariant equilibria which enables determination of fluid pressure and salinity (32.9-35.3 wt.% nacl equiv.). thermochemical properties of the h2o-nacl saturated solutions (haas, 1976) constrain the pressure at 16.5 bars or 32.7 bars, respectively. halite undersaturated inclusions show eutectic melting at temperatures ranging from -60º to 51ºc, followed by hydrohalite melting at temperatures ranging from -27.5º to -20.8ºc. ice melting in a range from -23º (undercooling below 21.2 ºc) to -2.5ºc, indicate salinities from 22.5 to 3.5 wt. % nacl equiv. they all homogenized by vapour disappearance, in the temperature range of 11º 210ºc. figure 11. histograms of microthermometric measurement for the inclusions from quartz in zebra siderite and quartz from mesothermal siderite veins. the histograms present frequency of a) eutectic temperature (te); b) hydrohalvite melting temperature (tm hyd); c) final ice melting temperature (tm ice); d) salinity; and e) total homogenization temperature (th). 15 palinkaš et al.: the ljubija geothermal field: a herald of the pangea break-up (nw bosnia and herzegovina) the extremely low eutectic temperature (te) observed in some quartz samples could be interpreted as a metastable eutecticum in cacl2-nacl-h2o or mgcl2-nacl-h2o systems (davies et al. 1990), but can also be explained by the presence of li+ ions in ore bearing fluids as well. fluid inclusion study in siderite from metasomatic zebra siderite (adamuša locality) fluid inclusions have been studied in siderite crystals separated from light bands within metasomatic zebra ore. most inclusions in siderite crystals are two-phase (l+v) and can be defined as primary. they acquire negative crystal, or irregular, three-dimensional shapes and are distributed irregularly within the crystals. primary inclusions show consistent liquid–vapour (l/v) volume ratios, which indicate entrapment of a homogenous fluid. the eutectic temperature spans the range between -53° and -49.9°c, suggesting a cacl2-nacl-h2o system. hydrohalite melting occurs in the narrow range between -31.1° and -29.0°c. ice melting temperatures recorded in an interval from -12.0° to -10.1°c corresponds to a salinity between 14.1 and 16.0 wt.% nacl equiv. total homogenization, always into the liquid phase, ranges between 147 and 164°c. secondary two-phase (l-v) inclusions are recorded as well, but they have not been measured due to their small size. fluid inclusion study in quartz from hydrothermal quartzsiderite veins (adamuša locality) vein-type siderite contains two types of quartz crystals: irregular, milky white quartz which does not contain measurable fis, and semi-transparent quartz-siderite intergrowth, containing type iii; primary liquid-rich inclusions, with or without an anisotropic daughter mineral, (l+v±sa); type iv; pseudosecondary liquid-rich inclusions (sometimes with an anisotropic daughter mineral), (l±v±shal) generating vapour bubbles after the freezing run. this is either a sign that our fluid inclusions were stretched during the freezing run or just metastability is affecting the re-apperance of the vapour phase after freezing. primary inclusions show eutectic melting at temperatures ranging from -63ºc to -43ºc, followed by hydrohalite melting at temperatures from -31.0º to -21ºc. salinities calculated from the ice melting temperatures (-17.7º to -7.1ºc) ranged from 20 to 11.5 wt.% (in those inclusions with the presence of a vapour phase at room temperature) nacl equiv. several inclusions show eutectic melting at -4.7ºc and gas hydrate melting at +10ºc, suggesting the pre sence of bicarbonates and co2 hydrates. homogenization was in the range from 97º to 250ºc. pseudosecondary liquid-rich inclusions show eutectic melting at temperatures between -60º to -44ºc, followed by hydrohalite melting between -34º to 22ºc and ice melting between -7.1º to -1.4ºc. calculated salinities ranged from 2.0 to 9.0 wt.% nacl equiv., whereas homogenization temperatures (by vapour disappearance) range from 90º to 133ºc. fluid inclusion study in siderite from hydrothermal quartz-siderite veins (adamuša locality) several primary fluid inclusions have been recorded in sparry siderite crystals from siderite veins hosted by the carboni ferous shale. a eutectic temperature around -52°c suggests a cacl2nacl-h2o system. hydrohalite melting spans an interval between -29.5° and -21.0°c. ice melting temperature recorded between -4.2° and -3.5°c points to a salinity between 5.7 and 6.7 wt.% nacl equiv. homogenization into the liquid phase occurs in the range from 120° to 127°c. results of microthermometric measurements on quartz from the three principal types of the fe mineralisation in ljubija/adamuša are presented in fig. 11. figure 12. ternary-component diagram nacl-cacl2-h2o for all measured inclusions in ljubija/adamuša ore field. shift of composition from nacl-h2o line toward cacl2-h2o line is a result of metasomatism. a wide variation of salinity points to the mixing of two contrasting fluids, high density fluid 1with low density fluid 2. figure 13. diagram of temperature of homogenization vs. salinity, ljubija/adamuša for fluid inclusions in the ore field ljubija/ adamuša, another confirmation of the mixing of two contrasting fluids, high salinity, high temperature fluid 1 and low salinity, low temperature fluid 2. 16 vol. 69/1 a ternary diagram nacl-cacl2-h2o (fig. 12) for all types of fis in the ljubija/ adamuša deposit shows a shift of data points from the nacl-h2o line toward the cacl2-h2o according to the dominant metasomatic process. the diagram also emphasizes the wide distribution of salinity from very low to very high. an explanation is suggested by the diagram th vs. salinity (fig. 13). the diagram shows a wide range of high to low salinity, and a narrow but declining trend of th, from high to low, which suggests the mixing of the two types of contrasting fluids. the high temperature, high salinity, type i, true evaporitic brine, and the low temperature, low salinity type ii, indicating that the sea water not only evolved by evaporation. mixing happened a few hundred metres close to the topographic surface. a p-t diagram with isochores calculated by the isoc computer program is presented in figure 14. fluid inclusion study in fluorite from a fluorite-barite vein (žune-dolinac locality) purple fluorite crystals with well developed growth zones were selected for the fluid inclusion analysis. the petrography revealed the presence of various inclusion types, classified as primary: type i; liquid-rich aqueous inclusions containing a halite daughter mineral and an unknown anisotropic daughter mineral, high salinity (l+v+shal±sa) (fig. 15b), type ii; liquidrich aqueous inclusions containing an anisotropic daughter mineral, high salinity (l+v±sa), (fig. 15b), type iii; liquid-rich aqueous inclusions (l+v), low to moderate salinity, (fig.15d), type iv; vapour rich aqueous inclusion (v+l±sa), low to moderate salinity, possibility of leaking (fig. 15), type v; vapour rich with halite daughter mineral (v±l+shal) (figs. 15e,f), type vi; two immiscible liquids (l1+l2), no sign of fluorescence, neither freezing, type vii; vapour inclusions (v) (fig. 15f), type viii; solid inclusions (sa) (fig. 15c), anisotropic mineral present in the types i, ii, and iv. type ix; liquid inclusions (l), (fig. 15d), (important note that all numbered types coexist within one single grain, fig. 16). fluid inclusion study was performed on liquid rich and vapour rich inclusions with or without daughter minerals. halite saturated aqueous inclusions (± unknown anisotropic daughter mineral) type i and ii show first melting at temperatures from -66.4º to 49.0ºc, followed by ice melting in the temfigure 14. a) isochores for the end members (l+v+shal±sa) inclusions type i, and (l+v±sa) type ii in the quartz from zebra siderite, and b) end members inclusions (l+v±sa) type iii and iv in quartz from the mesothermal siderite veins. figure 15. fluid inclusions in fluorite in the barite-fluorite vein ore body žune-dolinac; a) array of primary inclusions in the central part of the fluorite crystal; b) primary fi-s (l+v+shal+sa), type i and (l+v) type iii; c) boiling effects – array of fis with different degrees of filling (l+v), (v+l), (l+v+shal+sa) and (l+v+sa), type ii, iii, iv, v; d) boiling effect – array of primary fis (l), (l+v), (v+l), type iii, iv and ix; e) coexistance of (l+v) and (l+v+shal) fis type i and ii; f) boiling effects – array of primary (l+v), (l+v+shal), (v), fis type i, ii and vii; g) primary (l+v+sa) fi type ii; and h) primary (v+l) fi type iv. important note, the listed types of fluid inclusions coexists within one single grain. graphical presentation of fluid inclusions depicting the great variability in salinity, density, number of phases, different solids, indicate a boiling system, and are presented in the drawing fig. 16. 17 palinkaš et al.: the ljubija geothermal field: a herald of the pangea break-up (nw bosnia and herzegovina) perature range from -41.2 to -21.6ºc and hydrohalite melting/ transformation between -35.5º to -1.2ºc. during heating, within the majority of the inclusions, the vapour phase disappeared first, followed by halite dissolution in the temperature range between 125º 297ºc. a single inclusion melted sylvite at 129ºc followed by halite melting at 139ºc. several inclusions melted halite in the temperature range from 8.1 to 11.4ºc, followed by the disappearance of the vapour phase at temperatures between 145 238ºc. salinities are between 26.0 and 41.7 wt% nacl equiv. halite undersaturated aqueous inclusions (l+v), type iii; show similar eutectic temperatures (te = -65.0º to -49.0 ºc), followed by hydrohalite melting (thyd = -35.6º to -21.0ºc). salinities are calculated from ice melting temperatures (tice = -21.1 to -1.2 ºc) and range from 25 to 3.5 wt% nacl equiv. homogenization into a liquid phase was in a temperature range from 175 to 275ºc. type iv, vapour rich aqueous inclusions show eutectic melting in a temperature range from -56º to 48ºc, followed by hydrohalite melting (thyd = -44º to -21ºc) or ice melting (tice = -38º to -3.1ºc). salinities range from 33.4 to 5.1 wt% nacl equiv, whereas homogenization to a vapour phase occurred in the range from 125º to 245ºc. several inclusions decrepitated during heating procedure (fig. 17). the co-existence of liquid rich inclusions type ii, (l+v+shal), of high salinity from 25 to 42 wt% nacl equiv, and type iv, vapour rich (v+l) with very low salinity between 0.4 to 5 wt% nacl equiv, homogenizing in the same temperature interval between 125 and 245 ºc, corroborate the indication of boiling. the inclusions with halite as the last homogenization phase after (l+v+shal)→(l+ shal) →(l) at 300ºc, and vapour rich inclusions with halite crystals (v+shal), and those with solid halite inclusions (shal) are the product of a distillation (boiling evaporation) process in a semiclosed system with variable pressure, communicating with the open space on the earth surface followed by heterogeneous trapping. however, the behaviour of these high salinity and low salinity fi-s, especially the type (v+shal), and solid inclusion (shal) cannot be explained by one single episode of boiling. this impressive collection of fluid inclusion types, (more than 9 in one single crystal) requires multistage episodes of boiling producing a mixture of liquid water and bubbles, suspension of crystalls, halite, sylvite, and unknown solids, trapped into one single crystal. it represents repeated boiling episodes under changable pressure, due to a change in hydraulic head, water table, pressure of gases (suspected hydrocarbon liquids in inclusions), breakage of sealing, or maybe the intrusion of hot superheated water or steam from below into low salinity meteoric water, causing the rise of vapour and boiling, etc. the ternary diagram nacl-cacl2-h2o (fig. 18), also indicates the boiling process. the th vs. salinity diagram also confirms boiling and the separation of high salinity liquids from low salinity vapour (fig. 19). in this plethora of fi-s types and disequilibrium conditions, there was an attempt to determine the pressure of boiling by coexisting inclusions in one crystal, 33.4 wt% nacl equiv. (l+v), and 0.4 wt% nacl equiv. (v+l), and homogenization at the same temperature, (th), at 245ºc which yields 36.1 bars. applying hydrostatic pressure, the depth of boiling would be 361 m (haas, 1976, 1971). figure 16. selection of fluid inclusion types in one single crystal of fluorite, žunedolinac locality (palinkaš, 1988). 18 vol. 69/1 5.3. laser raman spectroscopy laser raman spectroscopy was performed on fluid inclusions from fluorite (fluorite-barite vein, žune-dolinac locality) on the four-phase, (l+v+shal±sa) type i; the three-phase, (l+v±sa) type ii; two-phase (l+v) type iii. liquid-rich aqueous inclusions containing halite daughter minerals, with high salinity. at room temperature they are composed of aqueous liquid (broad shoulder at around 3400 cm-1) and aqueous gas and/or traces of co2 (peaks at 1278 and 1383 cm-1). other volatiles were not detected. at -21ºc fluid inclusions contain ice (a broad peak at 3100 cm-1) and hydrohalite (a doublet around 3418 cm-1 and a sharp peak at 3543 cm-1). 5.4. bulk crush-leach analyses bulk crush-leach analysis by ionic chromatography was performed on quartz, siderite, ankerite and galena from metasomatic zebra-type siderite; quartz, siderite, barite and galena samples from vein-type siderite, dark host limestone; bladed calcite (adamuša locality) and fluorite and barite samples from a fluorite-barite vein (žune-dolinac locality, table 1). recalculated bromine contents from leachates in quartz from metasomatic zebra siderite are elevated and vary between 535 and 685 ppm, whereas within vein-type siderite varies between 165 and 256 ppm (according to the procedure outlined by channer et al. (1999). the recalculated bromine concentration in fluorite from the žune-dolinac locality is similar to the quartz from the metasomatic zebra-type siderite, ranging from 430 ppm to 605 ppm. a high concentration of bromide is registered in the dark limestone and barite as well. na+, ca2+, k+, and mg2+are major cations, while the dominant anion is cl– followed by so4 2-. these data correspond to the observed low eutectic temperature and depression of hydrohalite melting, both indicating the presence of divalent cations within the fluids, with the exception of mg2+ which is figure 17. histograms of microthermometric measurement for the inclusions in the fluorite in the žune-dolinac barite-fluorite vein deposit. a) eutectic temperature (te); b) hydrohalite melting temperature (tm hyd); c) final ice melting temperature (tm ice); d) salinity; and e) total homogenization temperature (th). 19 palinkaš et al.: the ljubija geothermal field: a herald of the pangea break-up (nw bosnia and herzegovina) below the detection limit within quartz zebra siderite. it explains the precipitation of ankerite in the middle of the light bands, and the formation of saddle siderite crystals. high ca2+ and mg2+ concentrations are the direct results of intensive metasomatic ankeritization and sideritization. concentration of sulphate is between 0.1 wt % and 0.3 wt % within quartz from the zebra type minerallisation and between 0.3 wt % and 0.7 wt % within vein type quartz, whereas within fluorite samples (žune-dolinac locality) it is between 0.4 and 0.5 wt %. maximum so4 2values up to 30,000 ppm (3 wt.%), were observed within a single fluorite sample. this very high concentration level, not confirmed by presence of gypsum or anhydrite in the fluid inclusions, (due to high ca concentration), is most likely attributed to contamination (e.g., solid inclusions of barite) since barite is frequently found in the paragenesis. however, it also points to a significant change in the fluid chemistry responsible for the genesis of barite deposits, decreased depth of formation, and the increased contribution of sea water. a deficit of cations is observed in the vein-type quartz. this can be attributed to the presence of fe2+ within the fluids, which was not measured during the procedure or to the absorption of divalent cations to the quartz powder during the crushing procedure. the lithium content is highly elevated within zebra-type quartz and varies between 366 ppm and 2300 ppm, whereas for the vein type quartz it is in the range between 60 ppm and 150 ppm. fluorite samples have uniform lithium concentrations varying between 325 ppm and 405 ppm. the presence of li in the ore fluids was suspected by the extremely low eutectic temperature in quartz fluid inclusions from the zebra siderite down to -90 ºc. high li concentration in the leachates and the presence of dio-trioctachedral chlorites from the donbassite-tosuditecookeite solid solution and (lial4(si3al)o10(oh)8 (fig. 4c, slovenec & palinkaš, 2003) in the same cavity, confirms the high li concentration in evaporitic bitter brines taking part in siderite genesis. this is one piece of evidence which connects evolved sea water from permian evaporitic basins or lagoons with the ore forming process. high li and b concentrations are common components in evaporitic bitter brines elsewhere (steven & zvi, 2011; 209 ppm, lippmann et al.,1999). an additional contribution of li may come from leaching of the surrounding host rocks, shales and sandstones. (mccaffrey et al., 1987). cécile et. al. (2002) consider high-salinity fluids, derived from sedimentary basins, responsible for the li enrichment in fi-s in the barren quartz from the spanish central system (sierra de guadarrama). according to krauskopf (1982), the average shale contains 60 ppm of li, twice that of the average granite. diagram na/cl vs. cl/br follows the sea water evaporation line. the measured ratios are the result of sea water evaporation rate between 12 and 36 % (fig. 20a). it confirms the evapo ration trend on all samples of zebra siderite, vein siderite, ankerite, quartz in siderite veins, vein barite and dark limestone. galena exhibits very variable ratios. galena associated with zebra siderite has na+ around the sea water composition, and in the vein siderite, above sea water on the evaporation line. it means a possible contribution of halite dissolution from evaporites. it should be mentioned that sulphide paragene sis in the cavities within zebra siderite is the last phase in the succession of dark siderite-light siderite-quartzsphalerite-galena which suggests a prolonged time-span of ore formation. the caexcess vs. nadeficiency diagram (fig. 20b) shows a wide spectrum of contemporaneous ore forming processes which follow concurrently the metasomatism of carboniferous limestones and dolostones by hydrotherms. the major trends are: (i) caexces increases by metasomatism of carbonates, ankeritization and sideritization, and (ii) albitization of plagioclases (1 mole of na for 1 mole of ca). the temperature of fluids was also calculated on the basis of geothermometric pairs: na/k = 210-258 ºc (mean 184ºc); k/ mg = 261-443 ºc (mean 355ºc); na/k/ca = 280-441ºc (mean 328ºc); and na/li = 124-589ºc (mean 329ºc). the use of traditional geothermometric pairs which includes ca and mg, obtains unreliably high values. their use is provided for water/ fluid equilibria in the common aquifer rocks, while in the ljubija geothermal field metasomatism excessively predominates other equilibrium processes. in contrast, the na/k geothermometer gives reasonable temperature, although in geothermal and epithermal enviroments this geothermometer reflects the deep reservoir fluid/rock equilibration rather than the fluid inclusion entrapment temperature (simpson et al., 2015). 5.5. vitrinite reflectance nine of seventeen samples from the tomašica locality are selected for vitrinite reflection: (i) 6 host limestones; (ii) phyllite (aleurolite, frequently used in the literature on sana-una. palaeozoic lithology); (iii) siderite, and (iv) sulphide rich sediment, which all contained >0.5% of organic carbon. according to petrography, most of the samples are composed of amorphous organic matter (99-100%) with traces of vitrinite and rarely pyrobitumene. the exception is the sample composed of 70% amorphous organic matter and 30 % vitrinite. all samples show a high thermal alteration index (tai ~ 4). the degree of vitrinite figure 18. ternary-component diagram nacl-cacl2-h2o for all types of inclusions in fluorite from the žune-dolinac barite-fluorite vein deposit, ljubija ore field. shift of composition from nacl-h2o line toward cacl2-h2o line is a result of metasomatism. differentiation of high salinity and low salinity inclusions, however, could be attributed to the extensive boiling processes determined in the deposit. 20 vol. 69/1 sample mineralogy mineralisation type li+ (meq/l) na+ (meq/l) k+ (meq/l) mg2+ (meq/l) ca2+ (meg/l) f (meg/l) cl (meg/l) br (meq/l) i(meq/l) no3 2 (meq/l) so4 2 (meq/l) na (mol/l) lj 010/1 quartz siderite, zebra type 96 7481 609 1139 472 7584 22 119 145 325 lj 011/1 quartz siderite, zebra type 22 10392 823 315 7 11119 42 162 75 452 lj 014/1 quartz siderite, zebra type 103 10377 660 806 2 11425 43 74 451 pr-lj-12 quartz siderite, vein type 11 5336 476 683 12465 34 9344 47 0.5 4318 1341 232 pr-lj-13 quartz siderite, vein type 12 4391 452 581 12659 30 8381 27 0.6 998 454 191 pr-lj-14 quartz siderite, vein type 16 3081 249 363 11748 9 5496 20 0.5 465 327 134 lj 008/2 siderite siderite, zebra type 157 9834 544 2343 9419 32 14136 71 33 860 428 lj 010/2 siderite siderite, zebra type 314 14459 863 3763 11172 27 23017 258 65 90 629 lj 011/2 siderite siderite, zebra type 196 10099 761 4297 10995 33 15760 147 74 208 439 lj 013/2 siderite siderite, zebra type 246 11236 732 3899 8741 27 18174 149 31 489 lj/014/2 siderite siderite, zebra type 256 10226 570 4452 6635 7 16224 122 40 445 lj 015/2 siderite siderite, zebra type 209 10527 505 4418 7271 19 16665 123 29 458 pr-lj-1 siderite siderite, vein type 101 12534 544 6535 6337 145 30458 192 0.9 321 206 545 pr-lj-4 siderite siderite, vein type 188 8812 1844 5275 16245 62 20489 231 0.6 196 3527 383 pr-lj-5 siderite siderite, vein type 67 14884 856 741 1995 56 26356 114 1.7 820 <20 647 pr-lj-9 siderite siderite, vein type 417 10468 458 7720 12683 43 25633 338 0.7 196 1129 455 lj 009/2 ankerite siderite, zebra type 280 20159 735 10602 25392 20 31845 110 28 138 877 lj s-4 calcite hydrothermal calcite 216 46 268 16406 4 166 72 238 9 pr-lj-3 dark limestone host rock 62 3775 5269 2197 19779 227 6620 36 10.8 308 1358 164 pr-lj-8 dark limestone host rock 26 3032 436 1507 25951 121 4744 68 6.9 177 19065 132 pr-lj-6 barite siderite, vein type 16 4943 319 616 14378 9658 50 0.8 118 3965 215 pr-lj-7 barite siderite, vein type 3 3877 325 682 22685 46 8630 34 0.6 174 20654 169 lj 012/3 galena siderite, zebra type 3 4659 293 178 1624 13 6673 8 114 1492 203 pr-lj-2 galena siderite, vein type 4 5869 352 571 8487 126 10701 26 0.1 168 409 255 pr-lj-11 galena siderite, vein type 1455 96 315 1711 31 2034 <0,1 163 2243 63 žune/dolinac naziv mineral opis li+ (meq/l) na+ (meq/l) k+ (meq/l) mg2+ (meq/l) ca2+ (meg/l) f(meg/l) cl (meg/l) br (meq/l) i(meq/l) no3 2 (meq/l) so42 (meq/l) na (mol/l) dz 1/i fluorite barite-fluorite vein 34 6316 1073 1256 9490 7351 11896 58 683 564 275 dz 3/ii fluorite barite-fluorite vein 40 8281 421 382 9626 7040 15072 52 308 701 360 dz 3/iii fluorite barite-fluorite vein 49 10793 825 306 9260 7703 19137 88 185 651 469 dz 3/i fluorite barite-fluorite vein 53 8928 297 381 21709 6841 16199 50 156 494 388 dz 3/ii fluorite barite-fluorite vein 36 11963 436 277 8631 7895 13612 64 134 3343 520 dz 100 barite barite-fluorite vein 281 125 568 10824 982 257 269 10352 12 dz 101 barite barite-fluorite vein 373 167 169 3708 371 823 230 2815 16 dz 102 barite barite-fluorite vein 369 192 1839 130 779 197 2723 16 dz 103 barite barite-fluorite vein 15 9234 781 195 2374 52 18092 120 241 2133 402 pr-lj-10 barite barite-fluorite vein 395 47035 1353 14662 33533 60 76299 467 32.3 192 562 2046 pr-lj-10a barite barite-fluorite vein 336 72 1358 21291 11 146 0.1 202 18953 15 lj-10/a barite barite-fluorite vein <1 57 24 <2000 12160 35 102 1.0 84 16698 2 dz 106 quartz barite-fluorite vein 10 5065 537 262 5088 8 5804 27 609 823 220 dz 107 quartz barite-fluorite vein 3272 448 2248 8 3367 15 545 1109 142 table 1. ljubija/adamuša reflection within the limestones is represented by ro of 4.0 – 4.6%. using the diagram t-ro-t (time of effective heating, maximum temperature, vitrinite reflectance) gives a temperature of 200-210 ºc (bostick et al., 1979) and 247-258 ºc after (berker & pawlewitz, 1994); the sample of limestone with pyrobitumen has an ro of 4.6%, which appropriates to a temperature of 210 ºc and 258 ºc, respectively. within phyllites with 30% vitrinite, ro of 4.8 %, gives t of 215 ºc and 262 ºc, by two methods. sediments with sulphides, where ro = 3.7%, appropriate to t of 193 ºc and 228 ºc. a siderite sample with ro 3.2% gives t of 193ºc and 228ºc. the temperatues obtained are in good agreement with the fluid inclusion data, tboiling 240ºc, and na/k, where t is 210-258 ºc. 5.6. sulphur isotopes sulphur isotope compositions were determined on sulphides and sulfates. sulfur isotopic data are presented in table 2 (strmić palinkaš, 2004). the δ34s values of the sulphides increases in order to 3.0 ‰) ≤ chalcopyrite ≤ (-0.8 to +2.3 ‰) ≤sphalerite (+0.4 to +4.4 ‰) < pyrite (+5.4 to +8.5 ‰). there was no distinction perceived between sulphides separated from dark siderite and zebra ore. the δ34s values of barite samples (+9.2 to ± 0.2 ‰ v-cdt) fall within the range of the latest permian marine evaporites (holser & kaplan, 1966). the temperature of cogenetic geothermometric pairs was calculated by the constants given by ohmoto & rye (1979). the calculated temperature suggests the absence of isotopic equilibria. the reasonable temperature of 245ºc was 21 palinkaš et al.: the ljubija geothermal field: a herald of the pangea break-up (nw bosnia and herzegovina) cl (mol/l) br (mol/l) ca (mol/l) na/br (mol) evapor. (%) cl/br (mol) evapor. (%) geot. na/k (oc) geot. k2/mg (oc ) geot. na/k/ ca b=1/3 (oc ) geot. na/li cl<0.3m (oc ) geot. na/li cl>0.3m (oc ) ca/na mg/na caex (meq/l) nadef (meq/l) 214 0.28 28.42 1162 0.0 764 0.0 188.9 373.4 177.0 373.2 0.2 49.7 -142.1 314 0.53 7.87 857 0.0 595 12.0 186.7 407.7 64.6 190.0 0.0 5.2 -183.3 322 0.54 20.11 838 0.0 598 12.0 171.6 364.6 156.1 337.8 0.1 29.4 -175.2 264 0.59 311.03 393 15.0 446 15.1 195.8 392.0 330.2 64.0 189.1 2.3 0.1 613.2 -6.2 236 0.34 315.86 558 9.0 690 0.0 207.6 394.6 337.4 77.1 209.6 2.9 0.1 623.8 11.6 155 0.24 293.12 549 9.0 635 0.0 188.3 364.3 305.2 113.5 267.5 3.8 0.1 581.0 -1.2 399 0.89 235.03 481 10.7 449 15.5 163.0 352.6 309.2 195.6 405.2 1.0 0.2 456.7 -86.0 649 3.23 278.76 195 23.6 201 35.0 167.6 370.3 325.3 225.7 458.0 0.8 0.3 535.7 -72.5 445 1.83 274.34 239 20.4 242 26.8 183.2 355.0 336.5 214.4 438.1 1.1 0.4 533.8 -58.3 513 1.87 218.09 262 20.0 275 24.0 173.2 355.8 329.5 226.3 459.0 0.8 0.3 419.0 -49.4 458 1.53 165.56 290 19.0 299 23.0 163.4 332.1 316.3 240.6 484.7 0.6 0.4 315.8 -52.6 470 1.54 181.41 296 19.0 304 23.1 154.8 323.7 302.3 216.7 442.0 0.7 0.4 347.1 -55.0 859 2.40 158.12 227 21.0 358 20.1 149.6 315.4 300.8 141.2 313.0 0.5 0.5 287.4 191.1 578 2.89 405.34 133 30.0 200 35.0 281.4 422.3 441.0 223.6 454.3 1.8 0.6 791.3 112.0 743 1.43 49.78 454 12.0 521 12.0 165.3 443.4 350.9 103.2 251.0 0.1 74.6 -10.3 723 4.23 316.46 108 36.0 171 40.4 150.0 298.3 286.4 297.1 589.0 1.2 0.7 608.7 164.3 898 1.38 633.57 636 0.0 651 10.5 141.2 319.4 280.0 183.6 384.5 1.3 0.5 1237.0 -107.1 5 409.35 284.3 261.6 308.1 76.0 1.2 818.5 -5.4 187 0.45 493.51 367 15.0 417 16.4 198.6 410.4 5.2 0.6 980.7 -4.2 134 0.85 647.52 155 27.0 157 44.8 239.0 352.4 346.6 145.1 319.5 8.6 0.5 1290.5 -17.2 272 0.63 358.76 341 16.0 432 16.3 172.6 363.1 296.5 85.6 223.0 2.9 0.1 708.4 18.5 243 0.43 566.03 393 14.9 567 12.0 191.0 360.4 305.4 27.6 133.2 5.9 0.2 1123.9 40.0 188 0.10 40.52 2009 0.0 1866 0.0 170.9 408.8 325.0 20.9 123.0 0.3 0.0 74.7 -41.3 302 0.33 211.76 775 0.0 916 0.0 167.9 374.2 302.7 21.5 124.0 1.4 0.1 413.4 3.4 57 42.70 174.3 301.1 294.2 1.2 0.2 83.5 -14.1 mean: 184.7 355.3 328.1 148.7 329.5 4.8 0.4 žune/dolinac cl (mol/l) br (mol/l) ca (mol/l) na/br (mol) evapor. (%) cl/br (mol) evapor. (%) geot. na/k (oc) geot. k2/mg (oc ) geot. na/k/ ca b=1/3 (oc ) geot. na/li cl<0.3m (oc ) geot. na/li cl>0.3m (oc ) ca/na mg/na caex (meq/l) nadef (meq/l) 336 0.73 236.80 379 14.0 463 15.1 257.0 439.6 411.4 113.5 267.7 1.5 0.2 462.3 12.8 425 0.65 240.18 551 9.0 650 10.5 158.1 407.1 296.5 107.3 257.5 1.2 466.1 4.2 540 1.10 231.06 428 13.2 492 13.2 184.2 486.8 343.0 103.5 251.4 0.9 444.0 -6.8 457 0.63 541.67 617 0.0 726 0.0 137.2 376.8 254.1 120.0 278.2 2.4 1068.0 3.2 384 0.80 215.37 651 0.0 480 13.2 141.2 425.4 280.5 80.5 214.9 0.7 417.9 -191.3 7 270.08 390.1 298.8 399.8 38.6 2.0 539.9 -6.0 23 92.52 391.0 362.9 434.7 10.0 0.5 184.3 3.7 22 45.89 5.0 91.0 2.8 510 1.50 59.22 268 19.0 340 20.4 191.7 506.6 371.8 52.5 171.2 0.3 101.3 35.7 2152 5.85 836.68 350 15.0 368 20.5 131.2 352.1 279.9 143.7 317.2 0.7 0.3 1601.2 -201.5 4 531.24 284.3 241.6 317.5 63.3 4.0 1062.3 -11.1 3 303.42 379.8 333.7 212.4 606.7 -0.0 164 0.33 126.94 661 0.0 491 13.2 210.3 448.9 361.0 60.4 183.5 1.0 0.1 248.4 -80.0 95 0.19 56.10 757 0.0 505 13.0 234.2 388.3 0.7 109.0 -60.9 mean: 237.7 395.1 344.0 97.7 242.7 24.2 1.2 obtained by galena-sphalerite pair from cavities in the zebra siderite calculated by the equation of kiyosu (1973) and friedman & o’neil (1977). the δ34ssulphide-sulphatevs. δ34ssulphide diagram enabled determination of the δ34s∑s, r = xso4/xh2s by the equation after ohmoto (1986). a determined value of +9.2 ‰ v-cdt supports the evolution of permian sea water by evaporation as the main sulphur source. sulphur isotope values of sulphates were not affected by thermochemical reduction, it explains a low fugacity of sulfur and small quantity of sulfides including pyrite in the overall area. some contribution from the decomposition of organically-bound sulphur and oxidation of pyrite from the sedimenary host rocks, dark coloured clastics, are not excluded (fig. 21). 5.7. geochronology k/ar dating k/ar dating was performed on the following samples: (i) 5 phyllites from the trnava locality; (ii) 6 phyllites from the blagaj locality; (iii) 6 phyllites from the adamuša locality, 4 of them are fragments associated within vein-type siderite minera lization; (iv) a single phyllite sample from the tomašica locality; (v) single phyllite sample from jezero locality; (vi) limestone undissolved residuum from the adamuša locality, and (vii) 9 samples of rhyolite rocks from the trnava locality. whole rock phyllite samples (4 samples) from the trnava locality contain between 1.3 and 3.6 % of potassium and gave an age between 171.3±6.6 and 195.4±7.5 ma, whereas a single table 1. ljubija/adamuša 22 vol. 69/1 (4.2 % of potassium) gave an age of 188.7±7.1 and 193.7±7.3 ma. two whole rock phyllite samples (1.2 and 4.0 % of potassium) gave ages of 290.0±11.0 ma and 283.4±10.6 ma, respectively. additional 4 whole rock phyllites associated with veintype siderite mineralization (0.7 to 3.6 % of k) yielded ages between 200.0±9.0 and 236.0±9.0 ma. a whole rock phyllite sample from the tomašica locality contains 1.5 % of k and gave an age of 238.7±9.2 ma, whereas a whole rock phyllite sample from the jezero locality (3.9 % of k) yielded an age of 132.9±5.1 ma. whole rock analysis of the undissolved residuum of the limestone of the adamuša locality (2.1 % of k) gave an age of 220±10.0 ma. whole rock rhyolite samples (9 samples) of the trnava locality contain from 0.1 to 2.0 % potassium with an age range from 56.6±4.3 to 237.0±9.5 ma. wide spectrum of data from 56 ma to 290 ma on phyllites and volcanics shows different degrees of loss of radiogenic ar, due to long-term tectonism and associated thermal events in the polyphase metamorphic evolution of the dinarides (palinkaš & pecskay, 1996, unpublished, fig. 22). the first group (i), (283-290 ma), belongs to the post-variscan thermal event in lower permian time, connected with an incipient intra-continental rifting stage. it corresponds to the post-variscan ages determined in the mid-bosnian schists mts. (pamić et al., 2004). the group (ii) varies widely (175-238 ma) and represents disturbed ages by the later tectono-thermal events, as indicated by the 40ar/39ar dating. the third group (iii) with a lower cretaceous overprint (98-132 ma) is most likely a result of later resetting in a tectonically active zone. it has a regional significance and marks obduction related tectonism and metamorphism, traditionally named the eoalpine, which started 130 ma ago (hsü, 1989). this lower cretaceous overprint is recognized on the silurian-devonian metamorphic complex on the medvednica mts. ( 110-122 ma), (belak et al., 1996), on the drina-ivanjica palaeozoic block in serbia (129-139), (milovanović, 1984), and in the metarhyolites in the mid-bosnian schist mts. (92-121), (pamić et al., 2004). the group (iv), younger palaeocene overprint (56-64 ma) determined on volcanics, corresponds to the palaeocene early collision stage between africa (adria) and euroasia (tisia-moesia), the cause of the dinaride uplift in the eocene. pamić & pécskay (1996) reported late cretaceous k/ar ages of 94.3 and 85.4 ma from basalt and diabase from the northwestern side of the medvednica mts. 40ar/39ar analysis 40ar/39ar analysis is performed on the low potassium white mica concentrate (paragonitic white mica), from phyllite fragments associated with the vein type of mineralization. the white mica concentrate yields a strongly disturbed pattern. the low-energy steps of the age spectrum show significant excess argon and an age of 340 ma, whereas high energy steps gave a plateau-type of age at 275 ma constituting together 96.7 percent of 39ar (steps 2-4, fig. 23; borojević šoštarić, 2009). 40ar/39ar released spectra could be interpreted in another way. the plateau age of 340 ma might be an inherited variscan age (lower carboniferous) of the sedifigure 19. temperature of homogenization (th) vs. salinity diagram for the inclusions in the fluorite from the žune-dolinac barite-fluorite vein deposit. the span of th and salinities reflects the evolution of p-t-x condition during boiling. table 2. sulphur isotope data of sulphides and sulphates from the ljubija ore deposits. sample mineralogy δ34s (‰ v-cdt) js-lj-100-1 galena -0.5 js-lj-101-1 pyrite 7.6 js-lj-104-1 sphalerite 0.8 js-lj-104-2 chalcopyrite 2.3 js-lj-104-3 chalcopyrite 1.2 js-lj-105-1 pyrite 6.5 js-lj-106-1 pyrite 8.5 js-lj-106-4 pyrite 6.7 js-lj-107-1 galena -1.3 js-lj-107-2 barite 9.3 js-lj-108-1 galena -0.4 js-lj109-1 sphalerite 4.4 js-lj-109-2 barite 9.2 js-lj-109-3 galena 3 js-lj-112-1 sphalerite 0.8 js-lj-113-1 sphalerite 0.4 js-lj-113-4 galena -2.3 js-lj-113-5 chalcopyrite -0.8 mica concentrate (4.2 % of potassium) gave an age of 212.0±8.0 ma. whole rock phyllite samples (4 samples) from the blagaj locality (1.2 to 3.6 % of potassium) gave an age between 214.2±8.3 and 233.1±9.4 ma, whereas two mica concentrates 23 palinkaš et al.: the ljubija geothermal field: a herald of the pangea break-up (nw bosnia and herzegovina) ment, precursor of phyllite, overprinted by a lower permian thermal event. a white mica concentrate from the phyllite, sample ljub 1, from the palaeozoic sana-una unit yielded a plateau age of 335.1 ± 23.1 ma comprising 96.8 percent of 39ar released. the inverse isochrone plots show a slightly disturbed initial 40ar/36ar ratio of 322± 27 ma, and an age of 327±30 ma, together constituting 100 percent of 39ar released (borojević šoštarić, 2012). 6. ore genesis genesis of the ljubija ore deposits was a subject of controversy. the basic interpretation models have two approaches (i) a synsedimentary stratiform type with an obscure origin of iron, and the alternative (ii) hydrothermal replacement and epigenetic vein type. to solve the dilemma, in the past decades a number of analytical procedures and methodologies have been applied in building a convincing genetic model. there was a number of ambiguities which obscured the solution, and paved the ground for unsupported genetic hypotheses. the objective approach requires resolution of the following particularities: textural-structural characteristics, time of formation, source of metal, pressure, temperature and chemistry of the ore forming fluids, alterations, and not least, the metallogenic affiliation to the equivalent deposits in the frame of plate tectonic divisions and reconstruction of the dinarides, and the wider area within the neotethyan domain. 6.1. textural-structural characteristics the fe mineralisation in the ljubija ore field comprises stratabound siderite and ankerite bodies hosted by carboniferous limestones, and siderite-sulphide veins placed within organic rich shales. palinkaš (1988) recognized three major types of primary iron ore textures: (1) dark massive siderite and ankerite, and (2) zebra siderite composed of dark massive and light sparry siderite bands, and (3) sparry siderite veins hosted clastics (figs. 3, 4, 5). ore microscopy and transmitted light microscopy offer a visual observation of metasomatic processes (figs. 8, 9). the textural type (1) was formed by the metasomatic replacement of dark massive limestone by dark massive siderite. the differences between massive siderite (1) and zebra siderite texture (2) were the result of chemical kinetics controlled by temperature, acidity buffered by the host rocks, and salinity. all these parameters have been reasserted by the research data (palinkaš et al., 2003b; strmić palinkaš, 2004, 2009; borojević šoštarić, 2004). when the dissolution volumetric rate of calcite was equal to the precipitation volumetric rate of siderite, the primary texture was retained, i.e. dark metasomatical fe-carbonate was precipitated. in contrast, when the volumetric rate of dissolution was higher than the rate of precipitation, cavities are formed and the primary texture is lost. further supply of mineralizing fluid caused crystallization of light sparry siderite directly from solution (strmić palinkaš, 2004). the genesis of three textural types has been ascertained by the chemistry of metasomatic processes, (strmić palinkaš, 2004; strmić palinkaš et al., 2009) through the following contributions: (i) variations in δ13c values of the barren and mine ralized carbonates suggest the progressive replacement, and depositional character of vein siderite; (ii) the δ18o values of siderite and the calcite vein from dark massive siderite give a value of isotope equilibrium temperature, tisotope = 224 ºc; (iii) the δ18o values of siderite and quartz pairs from siderite veins give tisotope = 168 ºc; (iv) the δ34s values of sphalerite and galena pairs from zebra ore give tisotope = 245 ºc; (v) the δ34s value of barite falls within the range of contemporaneous permian sea water; (vi) barren massive limestones have a negative cen anomaly and negative eun typical of marine carbonates;(vi) posi tive eun in siderite indicates precipitation in a low-temperature environment (<250 ºc) from fluid which received their ree signature during fluid/rock interactions in a high temperature environment. a combination of positive eun and negative cen anomalies is inconceivable in sedimentary siderite; (vii) vein siderite has a negative eun due to its precipitation from fluids depleted from eu; (viii) the pristine/phitane ratio higher than 1 figure 20. a) diagram showing na/cl/br variation of fluids extracted as leachates from the ore and host minerals. most of data follow the evaporation trend, and only a few the trend of halite dissolution, the ljubija/adamuša ore deposit; b) diagram ca access vs. na deficiency with theoretical trends of fluid evolution. legend: hdl halite dissolution line; blf line of basinal fluids; zebra siderite, banded texture; vein mesothermal siderite; dark limestones, footwall of the ore mineralization. 24 vol. 69/1 figure 23. the 40ar/39ar analyses, performed on the low potassium white mica concentrate from phyllite fragments associated with the vein type of mineralization, yielded two ages, the low energy step of 340 ma, and a high energy step with a plateau age of 275 ma (fig. 23b). the first, variscan age of 340 ma, is overprinted by an early permian tectono-thermal event dated at 275 ma. these pairs of ages bear regional significance and are repeated steadily in the neighbouring area of the sana-una palaeozoic, in the trgovska gora and petrova gora ore districts hosted by the carboniferous sediments. 40ar/39ar released spectra show variscan plateau ages at 332.8±3.1 ma and 342.9±3.3 ma, overprinted by a thermal event at ca. 265.6±6.2 to 274.2±3.1 ma, interpreted as a maximum age of the hydrothermal activity (fig. 23a, borojević-šoštarić et al., 2009). in the barren and mineralized samples points to an oxic depositional environment for the host rock carbonates, an inconvenient condition for the synsedimentary deposition of siderite ore. a reducing environment during diagenesis, controlled by indigenous organic matter, however, is a prerequisite for epigenetic metasomatic sideritization. 6.2. temperature and chemistry of fluids study of fluid inclusions in quartz from three textural siderite types and within the siderite itself from the ore deposit adamuša/ ljubija, and fluorite from the fluorite-barite deposit žunedolinac supported by crush-leach analysis and vitrinate reflectance, paved the way to substantial information on ore forming fluids, their temperature and composition. the ore forming fluids with highly variable salinities (2-39 wt% nacl equiv., adamuša/ljubija; 5-33.4 wt% nacl equiv., žune-dolinac), are essentially modified sea water derived through different degrees of evaporation in lagoons, up to the point of halite precipitation (the evaporation line on the diagram na/cl vs cl/br). boiling phenomena, observed and determined on fluid inclusions, contributed to the variable salinity of fluids, which underwent distillation (boiling evaporation), at the topmost position of the cell, near the land surface. the boiling temperature was controlled by hydrostatic pressure at depths of 100200 m below the land surface. the hydrothermal solution in fluid inclusions is primarily represented by nacl-h2o and nacl-cacl2±mgcl2-h2o systems. ca2+ and mg2+ ions are evidence of the widespread metasomatic replacement of limestones and dolomites by fe2+ (caexcess vs. nadeficiency diagram). the high concentration of li+ ions in leachates, and the presence of cookeite, (lial4(si3al)10(oh)8) as an alteration mineral, confirm the engagement of chloride rich evaporitic sea water, responsible for the mobilization of metasomatic fe2+ from shale, but some proportion comes from leaching of li-rich mica. the so4 2ion, recorded in leachates, was essential for deposition of the ubiquitous barite deposits. in spite of a slight variation, the δ34s values of barite around +9.2%0 v-cdt, the δ34sbarite value bears witness to permian sea water as a dominant water supplier in the circulation cell. the minor thermochemical reduction of sulphate was the source of hsfor sulphide deposition. thermal characteristics of the ore forming fluids are confirmed by the study of fluid inclusions (th, 100-275ºc), na/k ratio in leachates (141-281ºc), vitrinite reflectance (210-260ºc) and stable isotope geothermometers (164-224ºc). this overall range of temperatures could be more specific in a sketch presenfigure 21. δ34ssulphide-sulphate vs. δ34ssulphide digram for coexisting sulphates and sulphides. the measured value at +9.2 ‰ v-cdt suggests an evaporative-evolved permian sea water as the main sulphur source. figure 22. the range of 40ar/39k values determined on 21 samples of phyllites and 7 samples of volcanics from the sana-una palaeozoic area (palinkaš & pecskay, 1996, unpub.). a b 25 palinkaš et al.: the ljubija geothermal field: a herald of the pangea break-up (nw bosnia and herzegovina) tation of thermal distribution in the hydrothermal circulation cell (fig. 24). the shape of the circulation cells, formed over the foci of high heat flow, at the adamuša/ljubija deposit, is defined by the position of isotherms reconstructed by the temperature of mineral formation. the chemical zonation is accompanied by thermal zonation. the highest trapping temperature and salinities are registered at the lower position of the cell, in the quartz of the zebra metasomatic siderite (salinity 35-39 wt% nacl equiv., th 215275ºc). the lowest temperature and salinity are measured in the quartz in siderite veins in the uppermost part of the cell (salinity 2-9 wt% nacl equiv., th 100-250ºc). the plume of heat controls the shape and the character of fluids from high salinity bitter brines at deeper parts of the cell, to the diluted aliquots, with lower salinity, supplied by normal sea or meteoric water. the wide range of temperatures suggest mixing of hot-high salinity water fluid 1 and cold-low salinity waters fluid 2 (fig. 13, diagram th vs. salinity). the žune-dolinac barite-fluorite deposit (like the other numerous barite deposits in the ljubija geothermal field) experienced intensive boiling due to their near-surface setting. 6.3. time of mineralization age determination relied on indirect methods, available during research, (i) 39k/40ar, (ii) 40ar/39ar, and (iii) origin of sulphur in the ore mineralization implied through its isotope signature. the k/ar blocking temperatures, determined on phyllites, indicate four significant thermal events. the group (i), (283-290 ma), belongs to the post-variscan thermal event in lower permian time, connected with the incipient intra-continental rifting stage. the group varies widely (175-238 ma) and represents disturbed ages by the later tectono-thermal events. the third group (iii) with a lower cretaceous overprint (98-132 ma) is most likely a result of later resetting in a tectonically active zone. the group (iv), younger palaeocene overprint (56-64 ma) determined on the volcanics, corresponds to a palaeocene early collisional stage between africa (adria) and eurasia (tisia-moesia). the first group (i) on the carboniferous phyllites is of primordial significance in the polyphase metamorphic history of the tethys (fig. 22). (ii) the 40ar/39ar analyses, performed on the low potassium white mica concentrate from phyllite fragments associated with the vein type of mineralization, yielded two ages, the low energy step of 340 ma, and a high energy step with a plateau age of 275 ma. the first, variscan age of 340 ma, is overprinted by an early permian tectono-thermal event dated at 275 ma. these pairs of ages bear regional significance and are repeated steadily in the neighbouring area of the sana-una palaeozoic, in the trgovska gora and petrova gora ore districts hosted by the carboniferous sediments. 40ar-39ar released spectra show variscan plateau ages at 332.8±3.1 ma and 342.9±3.3 ma, overprinted by a thermal event at ca. 265.6±6.2 to 274.2±3.1 ma, interpreted as a maximum age of the hydrothermal activity (fig. 23). the middle permian age of mineralisation is corroborated by the following arguments: (i) the mineralisation is hosted exclusively within carboniferous to early permian units. (ii) sulphur isotopes show a permian seawater signature, while the increased bromine content of the leachates points to evaporated seawater not to the evaporites themselves, as a source of sulphates. (iii) the 40ar/39ar spectra recorded thermal overprints at 265.6±6.2 and 274.2±3.1 ma for petrova gora and at 298.0±4.2 ma for trgovska gora, superimposed exclusively onto the variscan ages of the host rock. 6.4. ljubija geothermal field the ljubija ore deposits were formed within the ljubija geothermal field which extends into the trgovska gora and petrova gora palaeozoic terrains. the ljubija geothermal field deserves the term “geothermal field” by because of the areal extension of its ore deposits of several hundred square kilometres over the sanauna palaeozoic. the ljubija geothermal field incorporates a huge accumulation of fe-carbonate, sulphide, barite and fluorite a b figure 24. metasomatic-hydrothermal genetic model of the ljubija mineral deposits based on inorganic and organic geochemical data. shape of isotherms depict local heat foci and fluid flow in a geothermal field. 26 vol. 69/1 figure 25. palinspastic sketch shows the north hungarian triassic units, with special regard to ladinian palaeogeography (not to scale), kovács (1984). the sketch depicts advanced rifting in progress toward the northwest (present geographical orientation), dissecting pangea into the gondwanian and eurasian continental blocks. early rifting formations and phenomena, including permo-carboniferous geothermal fields, were covered by newly formed dinaridic and moesian carbonate platforms,. tectonic evolution, uplift, napping, thrusting and erosion uncovered their mineral load to the present exposed situation. abbreviations: r.-m. lj ljubija, tg trgovska gora, pg petrova gora, sg samoborska gora, rud rudabánya. mineralisation, with almost half a billion tonnes of fe ore, at the adamuša/ljubija, tomašica, and omarska ore districts. the chemistry, pressure and temperature of the thermal waters enriched in ca, mg, na, chloride and bromine, are common in rifting-related fluids elsewhere (e.g., hardi, 1990; rowland & sibson, 2004; simpson et al., 2015). the general characteristics of the ljubija geothermal field corresponds in many aspects to the salton sea geothermal field, an active rifting environment, regarding composition and temperature of ca rich brines, metaliferous sediments, etc. (craig, 1966; skinner et al., 1967). due to the initial phase of rifting, the crust in the passive margin was thinner than adjacent crust, and geothermal systems developed at high heat flow foci along an elongated rifting zone and fractures controlled convection circulation systems. here the geothermal water had been circulating to considerable depth (> 1 km), through mostly vertical fractures, to extract the heat from the rocks. saemundsson (2009) classified geothermal systems on the basis of geological setting, reservoir temperature and enthalpy: (i) low-temperature systems with reservoir temperatures at 1 km depth below 150°c; (ii) medium-temperature systems with reservoir temperature at 1 km depth between 150200°c; (iii) high-temperature systems with reservoir temperature at 1 km depth above 200°c, with reservoir fluid enthalpies greater than 800 kjkg-1. the pressure-temperature characteristics of the ljubija geothermal field are closer to the (iii) high temperature system. the ljubija geothermal field was water dominated, and at places, to varying degrees, vapour dominated. the enthalpy content in the two-phase boiling system in žune-dolinac was close to 982 kjkg-1 for the liquid phase and 2877 kjkg-1 for the developing vapour phase (data for the temperature of 245°c and salinity of 33 wt. % nacl). carboniferous and permian formations were cap rocks (total thickness of 600-800 m), a blanketing seal of the geothermal system and their rock formation were the object of metasomatic sideritization. the rifting fault zones provided conduits for fluid flow and heat flow, and hydraulic pressure forces fluids to the surface forming hot springs, fumaroles, etc., in the boiling zone, at places were the temperature and pressure followed the boiling point curve and where steam and water coexisted. the barite-fluorite vein deposit of žune/dolinac is a feeder zone of one of the many hot springs. thermal gradients calculated on the basis of hot hydrothermal water, issuing on the surface, and colder permo-carboniferous host rocks are not a convenient place to calculate a regional geothermal gradient. a proper geothermal gradiant, providing the thermal water, is in the aquifer reservoir below the carboniferous and permian formations. as initial rifting proceeded, listric fault systems formed and further subsidence resulted in the creation of a red sea type basin, developed by the formation of the neo-tethyan ocean crust. equivalent types of huge siderite-barite-polysulfide mine ralisations are situated within the similar geotectonic environment, however, with a much more complex tectono-thermal history in the course of the alpine orogeny. the siderite mineralisation with similar characteristics, in low to medium grade metamorphic variscan basement units, has been studied in the western carpathians and eastern alps (grecula et al.,1995; hurai et al., 2002, 2008a; radvanec et al., 2004; urban et al., 2006; hurai et al., 2008b, b; pohl, 1986; laube et al., 1995; prochaska & hafellner, 1994), ebner et al. (1999). the origin and age of this mineralisation is still under discussion. as a corollary, the ljubija geothermal field is a herald for the birth of the tethyan ocean and the onset of the new alpine wilson cycle. 27 palinkaš et al.: the ljubija geothermal field: a herald of the pangea break-up (nw bosnia and herzegovina) reconstruction of the opening scenario which loosely defines space, time and related geotectonic events is depicted on the palinspastic sketch of the north hungarian triassic units, with special reference to ladinian palaeogeography (not to scale!), (fig. 25, kovács, 1984). the sketch portrays advanced rifting in progress toward the northwest (present geographical orientation) dissecting pangea into the gondwana and eura sian continental blocks. early rifting formations and permo-carboniferous geothermal fields, were covered by newly growing dinaridic and moesian carbonate platforms on the opposite sides of divergent, drifting continental margins (palinkaš et al., 2016, this publication). tectonic evolution, uplift, napping, thrusting and erosion uncovered their mineral load to the present exposed situation. 7. summary the ljubija ore deposits are situated within the thick upper palaeozoic sequence of the allochthonous sana-una palaeozoic complex of the inner dinarides. the primary ore occurs as stratabound metasomatic bodies of iron carbonates within carboniferous limestones and dolostones, and siderite veins within the carboniferous phyllites and metasandstones. primary mineralization consists of siderite-ankerite-baritepolysulphides with three textural types, dark massive siderite, zebra siderite, alternation of dark and light siderite bends with sulphide cavities, and open space fillings in the veins. the shape of the cell is defined by isotherms based on mineral formation temperature, tentatively. the most influential processes in the formation of chemical components of fluids are metasomatic sideritization and ankeritization. the ore forming fluids are dominantly nacl-cacl2-h2o, with highly variable salinity (0.4 to 39 wt% nacl equiv.) and th between 100 and 310ºc. the hydrothermal fluids are a mixture of high-temperaturehigh-salinity permian evaporitic sea water, diluted by lowtemperature-low-salinity sea or meteoric waters. boiling of near-surface hydrothermal reservoirs contributed to the high variability of temperature and salinity of the fluids. sulphur isotopes confirm permian sea water as the major source of sulphates (δ34s +9.2 ‰ v-cdt) for barite formation. thermal reduction of marine sulphates supplies hsfor the precipitation of sulphides, which were deposited out of equilibria, with the exception of the cogenetic pair galena-sphalerite, formed at 245ºc. the temperature of formation determined by oxygen isotopes on calcite-siderite-quartz cogenetic mineral pairs is in the range between 164º to 224ºc. temperatures of the cation geothermometer (na/k) matches those obtained from fluid inclusion, vitrinite reflectance and isotope thermometry. the age determination recorded two prominent tectonothermal events, variscan (332.8±3.1 ma and 342.9±3.3 ma), overprinted by a thermal post-variscan event at ca. 265.6±6.2 to 274.2±3.1 ma, and interpreted as the maximum age of hydrothermal activity in the middle permian. the ages and thermal features coincide well with those in the neighbouring deposits in the palaeozoic of trgovska gora and the petrova gora mts., its counterparts in space and time, announcing the future break-up of pangea and the birth of tethys (fig. 26). acknowledgement this study was mostly supported by the croatian ministry of sciences, technology and sports (projects 119-0982709-1175). we are grateful to tamara troskot and darko španić (ina oil company) for valuable vitrinite reflection analyses, prof. ronald j. bakker (montanuniversität, leoben, austria) for figure 26. a simplified genetic model of the permian siderite-barite-polysulphide deposits, ljubija, trgovska gora, petrova gora, samoborska gora, bistra-medvednica, presently placed along the dinaridic carbonate platform, within the palaeozoic of the inner dinarides. as initial rifting proceeded and listric fault systems formed, further subsidence resulted in the creation of a red sea type basin, developing into the tethyan oceanic crust in late triassic time. the high heat flow in the early rifting structures created an array of circulating hydrothermal cells. 28 vol. 69/1 providing access to the raman spectrometry facilities, to štefica kampić for assistance in the lab work, to nenad raković and zorana sljepčević (arcelormittal, ljubija mining company) for the field assistance during numerous visits with or without students. we would like to thank reviewers, ferenc molnar and todor serafimovski, whose comments greatly improved the presentation and clarity of the paper. references bakker, r.j. (2003): package fluids 1. computer programs for analysis of fluid inclusion data and for modelling bulk fluid properties.– chem geol, 194, 3–23. doi: 10.1016/s0009-2541(02)00268-1 bakker, r.j. (1991): adaption of bowers & helgeson (1983) equation of state to isochore and fugacity coeficient calculation in the h2o-co2ch4-n2-nacl fluid system.– chem geol, 154, 225–236. belak, m., jamičić, d., crnko, j. & sremac, j. (1995): niskometamorfne stijene zelenih ortoškriljavaca i paraškriljavaca na cesti runolist-željezničar (low-metamorphic rocks, greenschists, ortometamorphic and parametamorphic on the road runolist-željezničar.– in: šikić, k. (ed.): geološki vodič medvednice (geological guide on medvednica), geol inst, zagreb, 104–107, zagreb. berker, c.e. & pawlevicz, m.j. (1994): calculation of vitrinite reflectance from thermal histories and peak temperature. a comparison of methods.– in: mukhopadhay, p.k. & dow, w.g. (eds): vitrinite reflectance as a maturity parameter: application and limitations. am chem soc acs, symp ser, 570, 216–229. washington. borojević šoštarić, s. (2004): geneza sideritno-baritno-polisulfidnih rudnih ležišta u paleozoiku unutrašnjih dinarida (genesis of siderite-barite-polysulfide ore deposits in palaeozoic of the inner dinarides).– master thesis, university of zagreb, p. 120. borojević šoštarić, s., palinkaš, a.l., strmić palinkaš, s., bermanec, v., neubauer, f., spangenberg, j.e. & prochaska, w. (2009): origin of siderite–barite-polysulfide mineralisation in petrova and trgovska gora mts., nw dinarides.– miner petrol, 97, 111–128. borojević šoštarić, s., neubauer, f., handler, r & palinkaš, l.a. (2012). tectonothermal history of the basement rocks within the nw dinarides: new 40ar/39ar ages and synthesis.– geol carpath, 63, 6, 441–452. bostick, n.h., cashman, s.m., mcculloh, t.h. & waddel, c.t. (1979): gradients of vitrinite reflectance and present temperature in the los angeles and ventura basin, california.– in: olitz, df. (ed.): low temperature metamorphism of kerogen and clay minerals. soc econ paleont miner, pacific sec, 65–96, los angeles. bottrell, s.h., yardley, b.w.d. & bucley, f. (1988): a modified crush-leach method for the analysis of fluid inclusion electrolytes.– bull mineral, 11, 279–290. burkhard, m. (1993): calcite twins, their geometry, apearance and significance as stress-strain markers and indicators of tectonic regime: a review.– j struc geol, 15, 351–368. can, i. (2002): a new improved na/k geothermometer by artificial neutral networks.– geothermics, 31, 751–760. channel, j.e.t., d’argenio, b. & horvath, f. (1979): adria, the african promontory in mesozoic mediterranean paleogeography.– earth-sci rev., 15, 213–202. cissarz, a. (1951): die stellung der lagerstätten jugoslaviens im geologischen raum.– geološki vesnik ix, 23–60. collins, plf. (1979): gas hydrates in co2 bearing fluid inclusions and the use of freezing data to estimating of salinity.– econ geol, 74, 1435–1444. craig, h. (1966): isotopic composition and origin of the red sea and salton sea geothermal brines.– science, 154, 3756, 1544–1548. doi: 10.1126/ science.154.3756.1544 cvijić, r. (2001): mineralni resursi željeza, pelitoidne rude ljubijske metalogenetske oblasti i perspektive razvoja (iron ore resources, pelitoid ore of the ljubija metallogenic province and development), (in serbian with english summary).– fac min geol, belgrade, p. 154. cvijić, r. (2004): geomenađment u funkciji koriščenja i razvoja mineralnih resursa ljubijske metalogenetske oblasti (geomanagement in the function of utility and development of mineral resources in the ljubija metallogenic district).– rudarski institut, prijedor, p. 348. davies, d.w., lowenstein, t.k. & spencer, r.j. (1990): melting behavior of fluid inclusions in laboratory-grown halite crystals in the systems naclh2o, nacl-kcl-h2o, nacl-mgcl2-h2o, and nacl-cacl2-h2o.– geochim cosmochim ac, 54, 591–601. doi: 10.1016/0016-7037(90)90355-o davisson, m.l. & criss, r.e. (1996): na-ca-cl relations in basinal fluids.– geochim cosmoshim ac, 60/15, 2743–2752. doi: 10.1016/00167037(96)00143-3 dercourt, j., ricou, l.e., & vrielynck, b. (1993): atlas tethys paleoenviromental maps.– gauthiers-villars, paris. 307 p. đereković, b., maksimčev, s., kujundžić, s., sunarić, o., hohrajn, j., kovačević, r., kačar, b., veljković, r., jojić, d., marić, lj., ložajić, m., pamić, j., kapeler, i., đorđević, d. & jurić, m. (1976): ogk sfrj 1:100 000, map prijedor, feder geol survey, belgrade. cécile, f., boiron, m.c., dubessy, j., chabiron, a., charoy, b., & crespot m. (2002): advances in lithium analysis in solids by means of laser-induced breakdown spectroscopy: an exploratory study.– geochim cosmochim ac, 66, 8, 1401–1407. ebner, f., cerny, i., eichorn, r., götzinger, m., paar, w., prochaska, w., & weber, l. (2000): mineral resources in the eastern alps and adjoining area.– in: neubauer & höck (eds): aspects of geology in austria, miner österr geol ges, 92, 157–184. ferril, d.a., morris, p.a., evans, m.a., burkhard, m., groshong, jr r.h., onash, c.m, (2004): calcite twin morphology: a low-temperature deformation geothermometer.– j str geol, 26, 1521–1529. doi: 10.1016/j.jsg.2003.11.028 fournier, r.o. & truesdell, a.h. (1973): an empirical na-k-ca geothermometer for natural waters.– geochim cosmochim ac, 37, 1255–1275. doi: 10.1016/0016-7037(73)90060-4 fridman, i. & o’neil, jr. (1977): compilation of stable isotope fractionation factors of geochemical interest.– us geol sur am bull, 63, 325–380. giggenbach, w.f. (1988): geothermal solute equilibria. derivation of nak-mg-ca geoindicators.– geochim cosmochim ac, 52, 2749–2765. doi: 10.1016/0016-7037(88)90143-3 grecula, p., abonyi, a., abonyiová, m., antaš, j., bartalský, b., bartalský, j., dianiška, i, drnzík, e., ïuïa, r., gargulák, m., gazdačko, l., kobulský, j., lörincz, l., macko, j., návesòák, d., németh, z., novotný, l., radvanec, m., rojkovič, i., rozložník, l., rozložník, o., varček, c. & zlocha, j. (1995): mineral deposits of the slovak ore mountains.– miner slovaca, monograph, 1, bratislava, 834 p. grubić a., protić l.j., filipović, i. & jovanović, d. (2000): new data on the palaeozoic of the sana-una area.– proceedings of the international symposium of the dinarides and the vardar zone. acad sci art rep serb, dept natur math and tech sci i, banja luka, 49–54. grubić, a. & cvijić, r. (2003): new contribution in geology and metallogeny of the ljubija iron ore mine.– mining inst., prijedor, 137 p. grubić, a. & protić l.j. (2003): novi prilozi za geologiju i metalogeniju rudnika gvozdja ljubija. grubić, a. & cvijić, p. (eds.): mining inst, prijedor, 1–137. haas, j.l. (1971): the effect of salinity on the maximum thermal gradient of hydothermal system at hydrostatic pressure.– econ geol, 66, 940–946. haas, j.l. (1976): thermodynamic properties of the coexisting phases and thermochemical properties of the nacl component in boiling nacl solutions.– geol survey bull, 1421-b. hardi, l.a. (1990): the roles of rifting and hydrothermal cacl2 brines in the origin of potash evaporites: an hypothesis.– am j sci, 290, 43–106. heinrich, c. & neubauer, f. (2002): cu–au–pb–zn–ag metallogeny of the alpinebalkan-carpathian-dinaride geodynamic province.– min deposita 37, 533–540. holser, w.t. & kaplan, i.r. (1966): isotope geochemistry of sedimentary sulfates.– chem geol, 1, 93–135. doi: 10.1016/0009-2541(66)90011-8 horita, j., friedman, t.j., lazar, b. & holland, h.d. (1991): the composition of permian seawater.– geochim cosmochim ac, 55, 417–432. doi: 10.1016/0016-7037(91)90001-l horvath, f. & d’argenio, b. (1985): subsidance history and tectonics of western adria margin.– ac geol hun, 28/(1–2), 109–117. hosieni k., reed a.h. & scanlon m.w. (1985): thermodynamics of the lambda transition and the equation of state of quartz.– am mineral, 70,782–793. hsü, kj. (1989): time and place in alpine orogenesis-the fermor lectures.– geo soc s p, 45, 421–443. doi: 10.1144/gsl.sp.1989.045.01.23 hurai, v., harčova, e., huraiova, m., ozdin, d., prochaska, w. & wiegerova, v. (2002): origin of siderite veins in the western carpathians i. p-t-xδ13c-δ18o relations in ore forming brines of the rudnany deposits.– ore geol rev, 21, 67–101. hurai, v., lexa o., schulmann, k., montigny, r., prochaska, w., frank, w, konecny., p, král j., thomas, r. & chovan, m. (2008a): mobilization of ore fluids during alpine metamorphism: evidence from hydrothermal veins in the variscan basement of western carpathians, slovakia.– geofluids, 8, 181–207. doi: 10.1111/j.1468-8123.2008.00216.x hurai, v., prochaska, w., lexa, o., schulmann, k., thomas, r. & ivan, p. (2008b): high-density nitrogen inclusions in barite from a giant siderite vein: implications for alpine evolution of the variscan basement of western carpathians, slovakia.– j metamorph geol, 26, 487–498. doi: 10.1111/j.1525-1314.2008.00775.x janković, s. (1977): major alpine metallogenic units in the northeastern mediterranean and concepts of plate tectonics.– in: janković, s. (ed.): 29 palinkaš et al.: the ljubija geothermal field: a herald of the pangea break-up (nw bosnia and herzegovina) metallogeny and plate tectonics in the northeastern mediterranean. igcp-unesco, correlation program, vol. 3, fac mining geol, belgrade, 105–172. janković, s. (1987): genetic types of the alpine ore deposits and their tectonic settings in the northeastern mediterranean and southwest asia.– in: petraschek, w.e. & janković, s. (eds.): geotectonic evolution and metallogeny of the mediterranean area and western asia. igcp 169, springer-verlag, wien, 23–36. doi: 10.1007/978-3-7091-5822-7_2 jeremić, m. (1958): baritno-fluoritno ležište žune kod ljubije (barite-fluorite deposit žune-dolinac near ljubija, in serbian).– rudarsko-metalurški zbornik, 4, ljubljana. jeremić, m. (1959): baritonosno područje une i sane u sjeverozapadnoj bosni (barite bearing region within the una and sana rivers in northwest bosnia, in serbian).– rudarstvo i metalurgija, 2, belgrad. jurković, i. (2003): metallogeny of southern tisia–moslavačka gora mt., and mts. psunj, papuk, krndija.– rudarsko-geološko-naftni zbornik, 15, 1–17 (in croatian). jurković, i. (1961): minerali željeznih rudnih ležišta ljubije kod prijedora (mineralogical investigation of iron ore deposits ljubija near prijedor in bosnia, in croation with english summary).– geološki vjesnik, 14, 161–220. jurić, m. (1971): geologija područja sanskog paleozoika u sjeverozapadnoj bosni (geology of sana palaeozoic, nw bosnia; in croation).– geološki glasnik, xi, sarajevo, p. 146. kiyosu, y. (1973): sulfur isotope fractionation among sphalerite, galena and sulfide ions.– geochem j, 7, 191–199. karamata s., krstić b., dimitrijević m.d., dimitrijević m.n., knežević v., stojanov, r. & filipović, i. (1997): terranes between the moesian plate and the adriatic sea.– ann geol pays hellén, 37, (1996/97), 429–477. katzer, f. (1910): die eisenerz lagerstätten bosniens und der herzegovina, manzsche hof: universitäts buchhandlung, vienna, 343 p. katzer, f. (1925): geologie bosniens und der herzegovina. direkcija državnih rudarskih poduzeća. sarajevo, p. 520. korzhinskii, d.s. (1968): the theory of metasomatic zoning.– miner deposita, 3, 222–231. doi: 10.1007/bf00207435 kovacs, s. (1984): north hungarian triassic facies types: a review.– ac geol hun, 27, (34), 251–264. krstić, b., filipović i., maslarević l.j., sudar, m. & ercegovac, m. (2005): carboniferous of the central part of balkan peninsula.– bull t cxxx, acad serbe sci art, cl. sci math nat, sci nat, 43, 41–56. laube, n., frimmel, h.e. & hoernes, s. (1995): oxygen and carbon isotopic study on the genesis of the steirischer erzberg siderite deposit (austria).– miner deposita, 30, 285– 293. doi: 10.1007/bf00196364 lippmann, m., truesdell, a. & frye, g. (1999): the cerros prieto and salton sea geothermal fieldsare they really alike?– proceedings of the 24th workshop on geothermal reservoir engineering, stanford university, stanford, california, 25–27. ludwig, k.r. (2001): using isoplot/ex, version 2.01: a geochronological, toolkit for microsoft excel.– berkeley geochronology center, spec p 1a, berkeley, 47 p. ludwig, k.r. (2005): isoplot/ex rev. 3.32: a geochronological toolkit for microsoft excel.– berkeley geochronology center spec p 4, berkeley. mccaffery, m.a., lazar, b. & holland, h.d. (1987): the evaporation path of seawater and the coprecipitation of brand k+ with halite.– j sediment petrol, 57, 928–937. merino, e., canals, a. & fletcher. r.c. (2006): genesis of self-organized zebra textures in burial dolomites: diplacives veins, induced stresses, and dolomititzation.– geol acta, vol. 4, 3, 383–393. milovanović, d. (1984): petrologija stena niskog stepena metamorfizma iz središnjeg dela drina-ivanjica paleozoika (petrology of low-metamorphic rocks from the middle part of drina-ivanjica palaeozoic; in serbian).– glas pri muz srp zemlje, (bull. museum serb lands), 39, 1–139, belgrade. naden, j. (1996): calcic brine: a microsoft excel 5.0 add-in for calculating salinities from microthermometric data in the system nacl−cacl2−h2o.– in: brown p.e, hagemann, s.g (eds): pacrofi vi, pan am conf res fluid inclusion: madison proceed, 97–98. nöth (1952): die eisenerzlagerstätten jugoslawiens. belgrade. ohmoto, h. & rye, r.o. (1979): isotopes of sulfur and carbon.– in: barnes h.l (ed.): geochemistry of hydrothermal ore deposits. wileyintersci pub, 509–561, new york. ohmoto, h. & lasaga, a. (1982): kinetics of reactions between aqueous sulfates and sulfides in hydtothermal systems.– geochim cosmochim ac, 46/10, 1727–1745. oliver, n.h.s. & bons, p.d. (2001): mechanisms of fluid flow and fluid rock interaction in fossil metamorphic hydrothermal systems inferred from vein-wallrock patterns, geometry and microstructure.– geofluids, 1, 137–162. doi: 10.1046/j.1468-8123.2001.00013.x petrascheck, w.e. (1977): some basic problems of metallogeny and plate tectonics in the eastern mediterranean.– in: janković, s. (ed): metallogeny and plate tectonics in the northeastern mediterranean. igcpunesco, corr program, vol 3, fac min geol, belgrade, 193–200. palinkaš, a.l. (1985): lead isotopes patterns in galenas from some selected ore deposits in croatia and nw bosnia.– geološki vjesnik, 38, 175–189. palinkaš, a.l. (1988): geokemijske karakteristike paleozojskih metalogenetskih područja: samoborska gora, gorski kotar, lika, kordun i banija (geochemical characteristics of palaeozoic metallogenic regions: samoborska gora, gorski kotar, lika, kordun and banija, in croatian with english summary).– diss, uni zagreb, 108 p. palinkaš, a.l. (1990): siderite-barite-polysulfide deposits and early continental rifting in dinarides.– geološki vjesnik, 43, 181–185. palinkaš, a.l., borojević, s., prochaska, w., šinkovec, b. & šiftar, d. (2000): rude samobor, siderite-hematite-polysulfide-barite mineral deposit within the zagorje-mid-transdanubian zone, nw croatia.– in: tomljenović, b., balen, d. & saftić, b. (eds): vijesti, abstracts, proc. pancardi 2000, dubrovnik, 37/3, 96–98. palinkaš, a.l., borojević, s., prochaska, w., šinkovec, b. & šiftar, d. (2001): rude samobor deposit as a prototype of siderite-barite-polysulfide-hematite mineralization in the inner dinarides, croatia.– in: piestrzynski, a. (ed): mineral deposits at the beginning of the 21st century. proc. joint 6th biennial sga-seg meeting, krakow, poland, balkema rotterdam, 317–320. palinkaš, a.l., borojević, s., strmić, s., prochaska, w. & spangenberg, j.e. (2003a): siderite-hematite-barite-polysulfide mine ral deposits related to the early intracontinental tethyan rifting, inner dinarides.– in: eliopoulos et al. (eds): mineral exploration and sustainable development, millpress, rotterdam, 1225–1228. palinkaš, a.l., borojević šoštarić, s., strmić palinkaš, s., balogh, k., prochaska, w. & šiftar, d. (2003b): ljubija siderite ore field, nw bosnia, a precursor of the early intra-continental rifting of the tethys.– in: neubauer & handler (eds.): geodynamics and ore deposit evolution of the alpine-balkan-carpathian-dinaride province. proc. of the final geode-abcd workshop. seggauberg, austria, uni salzburg, p. 65. palinkaš, a.l., borojević šoštarić, s., strmić palinkaš, s., prochaska, w. & cuna, s. (2010): permian polysulfide-sideritebarite-haematite deposit rude in samoborska gora mts., zagorje-midtransdanubian zone of internal dinarides.– geol croat, 63/1, 93–115. doi: 10.4154/gc.2010.06 palinkaš, a.l., strmić, s., garašić, v., jurković, i. & majer, v. (2001): permian metarhyolites and related ore deposits, central bosnia. abstracts of the geode workshop.– romanian jour mineral deposits, 79, 75–76. palinkaš, a.l., borojević šoštarić, s., strmić palinkaš, s., crnjaković, m., neubauer, f., molnar, f. & bermanec, v. (2010): volcanoes in the adriatic sea: permo-triassic magmatism on the adriatic-dinaric carbonate platform.– acta mineralogica-petrographica, 8, 1–15. pamić, j. (1984): triassic magmatism of the dinarides in yugoslavia.– tectonophysics, 109, 273–307. doi: 10.1016/0040-1951(84)90145-8 pamić, j. & pécskay, z. 1996: geological and k/ar ages of tertiary volcanic formations from the southern part of the panonian basin in croatia – based on surface and subsurface data.– nafta, 47, 195–202, zagreb. pamić, j. & jurković, i. (1997): alpine magmatic-metallogenic formations of the northwestern and central dinarides.– rudarsko-geološkonaftni zbornik, 9, 1–9. pamić, j., gušić, j. & jelaska, v. (1998): geodynamic evolution of the central dinarides.– tectonophysics, 297, 251–268. pamić, j., balogh, k., hrvatović, h., balen, d., jurković, i. & palinkaš, a.l. (2004): ar and ar-ar dating of the palaeozoic metamorphic complex from the mid-bosnian schist mts., central dinarides in bosnia and herzegovina.– miner petrol, 82, 65–89. pavlović, p. (2004): evaluation of the potential of salar del rincon brine deposit as a source of lithium, potash, boron and other mineral resources.– unpublished report, for argentina diamonds ltd. pohl, w. (1986) comparative metallogeny of siderite deposits.– öst schrift erdwiss komm, wien, 8, 271–282. doi: 10.1007/978-3-7091-5822-7_22 prochaska, w. & hafellner, m. (1994) pretertiary siderite mineralization in the eastern alps.– in: grecula, p. & nemeth, z. (eds.): variscan metallogeny in the alpine orogenic belt. proc. inter conf, stará lesná, slovakia, p. 17. prochaska, w. (1997): formation of different siderite provinces during the alpine tectono-metamorphic events in the eastern alps of austria.– in: papunen (ed.): mineral deposits: research and exploration – where do they meet? proc. 4th biennial sga meeting, turku, finland, balkema rotterdam, 845–848. radvanec, m., grecula, p. & žák, k. (2004): siderite mineralization of the gemericum superunit (western carpathians, slovakia): review and a revised genetic model.– ore geol rev, 24, 267–298. doi: 10.1016/j. oregeorev.2003.07.004 30 vol. 69/1 ramović (1957): pregled olovno-cinčanih ležišta bosne i hercegovine (the review of lead and zinc mineral deposits in bosnia and herzegovina; in bosnian).– geološki glasnik, sarajevo, 3, 5–124. roedder, e. (1984): fluid inclusions.– reviews in mineralogy. miner soc am, 12, 644 p., washington. rottura, a., bargossi, g.m, caggianelli, a., del moro, a., visona, d., & tranne, c.a. (1998): origin and significance of the permian high-k calc-alkaline magmatism in the central-eastern southern alps, italy.– lithos, 45, 329–348. doi: 10.1016/s0024-4937(98)00038-3 rowland, j.v. & sibson, r.h. (2001): extensional fault kinematics within the taupo volcanic zone, new zealand: soft-linked segmentation of a continental rift system.– n zeal j geol geop, 44, 271–283. doi: 10.1080/00288306.2001.9514938 saerl, a. (1989): saddle dolomite: a new view of its nature and origin.– miner mag, 53, 547–555. doi: 10.1180/minmag.1989.053.373.05 saemundsson (2009): exploration for geothermal resources, geothermal systems in global perspective geothermal training programme organized by unu-gtp, kenya. sheperd, t.j., rankin, ah. & alderton, d.h.m. (1985): a practical guide to fluid inclusion studies.– blackie & son ltd., glasgow, 239 p. sibley, d.f. & gregg, j.m. (1987): classification of dolomite rock.– j sediment petrol, 57, 6967–975. simpson, m.p., strmic palinkas, s., mauk, j.l. & bodnar, r.j. (2015): fluid inclusion chemistry of adularia-sericite epithermal au-ag deposits of the southern hauraki goldfield, new zealand.– econ geol, 110, 763–786. doi: 10.2113/econgeo.110.3.763 skinner, b.j., rose, h.j. & mays, r.e. (1967): sulfides associated with the salton sea geothermal brine.– econ geol, 62/3, 316–330. doi: 10.2113/ gsecongeo.62.3.316 slovenec, d. & palinkaš, a.l. (2003): note in: slovenec, d. & bermanec, v. sistematska mineralogija-mineralogija silikata (systematic mineralogysilicate mineralogy), uni. zagreb, 359 p. steven, t. & zvi, c. (2011): lithium production from highly saline dead sea brines.– rev chem engineering, 9/3–4, 293–318. szakall, s. (2001): comparison of the rudabanya (hungary) and nižna slana (slovakia) metasomatic iron and hydrothermal sulphide ore deposits with special references to the mineral paragenesis of rudabanja.– diss, tech uni košice, 154 p. strmić palinkaš, s. (2004): organic and inorganic geochemistry of ljubija mineral deposits, nw bosnia.– master thesis, uni zagreb, 101 p. strmić palinkaš, s., spangenberg, j.e. & palinkaš a.l. (2009): organic and inorganic geochemistry of ljubija siderite deposits, nw bosnia and herzegovina.– miner deposita, 44, 893–913. stipp, m., stünitz, h., heilbronner, r. & schmidt, s.m. (2002): the eastern tonale fault zone: a „natural laboratory“ or crystal plastic deformation of quartz over temperature range from 250 to 700oc.– j struc geol, 24, 1861–1884. doi: 10.1016/s0191-8141(02)00035-4 šarac, m. (1981): metalogenetske karakteristike rudonosne oblasti ljubije (metallogenic characteristics of the ljubija ore-bearing region; in serbian).– doc thesis, uni belgrade, belgrade, 135 p. urban, m., thomas, r., hurai, v., konečný, k. & chovan, m. (2006): superdense co2 inclusions in cretaceous quartz-stibnite veins hosted in low-grade variscan basement of the western carpathians, slovakia.– miner deposita, 40, 867–873. doi: 10.1007/s00126-005-0042-6 verma, s.p. & santoyoa, e. (1997): new improved equation for na/k, na/li and sio2 geothermometers by outlier detection and rejection.– j volcanol geoth res, 79, 9–23. warne, s. st. j. (1962): a quick field or laboratory staining scheme for the differentiation of the major carbonate minerals.– j sed petrol, 32, 29–38. zhang, y.g. & frantz, j.d. (1987): determination of the homogenization temperatures and densities of supercritical fluids in the system nacl−kcl− cacl2−h2o using synthetic fluid inclusions.– chem geol, 64, 335–350. 07 buda.indd buda et al.: mafi c enclaves in peraluminous variscan granitoid in the battonya unit from southeast hungary 243 � ab stra ct variscan granitoids occur in the southeastern part of the tisza mega unit of hungary. the presence of amphibole, calc-alkaline-type mg-rich biotite in metaluminous basic enclaves, and muscovite and fe-al-biotite in peraluminous granitoids, suggests a mixed i-s-type origin. two types of muscovite have been identifi ed: a primary euhedral to subhedral, ti-na-al rich variety, crystallized after fe-rich peraluminous biotite in the two-mica granite and in muscovite granite, and a secondary subhedral si enriched and mg-bearing, ti-poor mica formed as a hydrothermal alteration product of feldspars, and is present in all rock types. given the compositional continuum of “white micas”, we suggest that magmatic crystallization was followed by autometasomatic and hydrothermal activity, due to a water-rich liquid trapped in the rock during the fi nal stages of magmatic activity. based on the bulk composition of the prevailing rock-type, the abundance of primary muscovite, the majority of the granitoid magma crystallized from a watersaturated peraluminous melt for which the pressure was 490–600 mpa, the temperatures were 650–685 °c and the depth of the intrusion was a minimum of 15 km. keywords: basic enclave, peraluminous granitoid, variscan, i/s-type, primary-, secondary muscovite, p, t, depth of intrusion, se hungary mafi c enclaves in peraluminous variscan granitoid in the battonya unit from southeast hungary � györgy buda1, elemér pál-molnár2 and friedrich koller3 1 department of mineralogy, eötvös loránd university, h-1117 budapest, pázmány p. st. 1/c, hungary; (buda@ludens.elte.hu) 2 department of mineralogy, geochemistry and petrology, university of szeged, h-6701 szeged, p.o. box 651, hungary; (palm@geo.u-szeged.hu) 3 department of lithospheric research, university of vienna, a-1090 vienna althanstrasse 14, austria; (friedrich.koller@univie.ac.at) doi: 104154/gc.2012.15 geologia croatica 65/2 243–253 8 figs. 3 tabs. zagreb 2012 geologia croaticageologia croatica 1. introduction variscan granitoids occur in the carpathian basin (hungary). the present geology and tectonic setting of the carpathian or pannonian basin (fi g. 1/a), are the result of a multi-step evolution of geological structures (haas et al., 2000; kovács et al., 2000, haas et al., 2004; schmid et al., 2008 ). the complexity is due to the tectonic position of the territory. it is situated in the collision zone of the european and african continental plates. the history began with spreading, followed by a series of collisions. during the alpine orogenesis, the drifting and welding of the individual fragments was accompanied by folding processes and nappe formation. at the end of the miocene, attenuation of the crust (upward bulging of the mantle) resulted in the development of a large basin that determines the present structural setting of the area. the greatest proportion of the pre-neogene basement of the pannonian basin is composed of two megatectonic units: in the north the alcapa mega unit (the southern part of which is named the pelso composite unit) and in the south geologia croatica 65/2geologia croatica 244 the tisza mega unit (tmu, kovács et al. 2000) or tisia composite terran (kovács et al., 2010). in the hungarian part of the variscan tmu (fi g. 1/b) two types of granitoids can be distinguished: an older (354 ma, klötzli et al., 2004) deep-seated metaluminous and slightly peraluminous, kand mg-rich, iand allanite-type granitod, with k-mg-rich basic durbachitic enclaves (buda et al., 2004/a), occurring in the southwest part of the tmu outcropping in the mórágy unit (mecsek mts) and a slightly younger granitoid which is mostly strongly peraluminous with mafi c enclaves, i/sand monazite-type (buda et al., 2009) in the southeastern part of the tmu located in the characteristic uplift of the basement of the battonya unit, studied only from oil prospecting drill-core samples. one of the main purposes of this study to distinguish primary muscovite from secondary muscovite in the peraluminous granitoid in order to estimate the p/t of crystallization and the depth of intrusion of the battony granitoids. for this estimation it was important to prove the presence of primary muscovite in these altered rocks because the breakdown curve of primary muscovite (clarke et al., 2005), which intersects the experimentally determined watersaturated peraluminous granite solidus (johannes & holtz), can give a rather good estimation for the physical parameters of crystallization and depth of intrusion. due to the volatile enriched environment, subsolidus muscovite is also widespread; consequently we had to use different criteria to distinguish them from primary muscovite. the role of basic enclaves in the peraluminous granitoid is not clear, and requires further research. 2. outline of geological setting the tmu comprises the crystalline basement of south hungary, east croatia, north serbia, and the western part of transylvania (romania, fig.1/a). it is bordered by the mid hungarian lineament, the szá va -mosla vima -zomborbečej-lipova line, (the northern border of the srem – mureş ophiolite belt), and the someş lineament in the northwest, south and northeast, respectively. as a consequence of the fact that at present, the basement is covered by 1000–6500 m of miocene-pliocene sediments, its structure and petrology can only be investigated by geophysical methods and borehole samples. the seismic research of the past decades has shown that during the neogene, the pannonian basin underwent a complex tectonic evolution that has principally modifi ed the original variscan structures of the area (tari et al., 1999; csontos et al., 1999). as an independent unit, the tmu existed from the late cretaceous, when its rotation began, until the early miocene (csontos, 1995; márton, 2000, 2001; kovács et al., 2000). separation from the moldanubian zone of variscan figure 1: a – sketch map of the main tectonic units of central europe (cbp= central bohemian pluton, sbp=south bohemian pluton, mhl=mid hungarian lineament). b – structural units of the hungarian part of the tisza mega unit. inset: simplifi ed geological map of békesian composite unit after kovács et al. (2000), modifi ed by pál-molnár et al. (2001). c. location of bore-holes of the battony unit. buda et al.: mafi c enclaves in peraluminous variscan granitoid in the battonya unit from southeast hungary geologia croatica 245 europe started in the late triassic–early cretaceous, as recorded by crystalline rocks (buda et al., 2004/b) and sedimentary sequences (haas et al., 2004; csontos et al., 2004; schmid et al., 2008). the hungarian part of the tmu is called the kunságia composite unit and the békésia composite unit (bcu). the bcu can be divided into four units: kelebia, csongrád, battonya, and sarkadkeresztúr (fi g. 1/b). the areas of interest are located in the bcu, which is part of the békés-codru alpine zone (haas et al., 2004). the battonya unit is a 15–25 km long and 10–15 km wide body forming a fl at anticline covered by 1000–1500 m of miocene and pannonian sediments. the present study fi rst of all deals with the genesis of “white micas” of mostly two-mica and muscovite granitoids, occurring in the uplifted basement of the battonya unit. these plutonic rocks are surrounded by regional metamorphic and migmatitic rocks and are partly covered by alpine sequences. the rocks were metamorphosed at about 6–700 mpa and 500–570°c (350–330 ma) and are locally affected by dynamoand retrograde metamorphism (330–315 ma) according to szederkényi (2001). 3. sampling and analytical methods the studied samples were obtained from boreholes of the battonya unit around the battonya and mezőhegyes (fig. 1/c/i., ii.) settlements. the rocks were acquired from the rock collection of the department of mineralogy, geochemistry and petrology of the university of szeged. the samples are drill-cores and consequently their numbers are limited. the major and trace element analyses of the rocks were carried out using icp-aes methods at the university of stockholm and at als chemex in canada (vancouver). most of the analyses were published by pál-molnár et al. (2001). detection limits for major components are 0.01wt %, feo content was determined by titrimetric and h2o– and h2o+ by gravimetric methods. major element compositions of minerals were determined by a cameca sx100 electron probe x-ray microanalyser at the department of lithospheric research of the university of vienna. during the measurements an accelerating voltage of 15 kv and a beam current of 10 na were used. a beam size of 1–2 μm was used for amphiboles, micas and other minerals, for feldspar minerals a beam size of 5 µm was used. the counting time was for each element ranged from 20–40 sec. for calibration, well defi ned mineral standards were used (quartz for si, rutile for ti, almandine for al and fe, a chromite for cr, spessartine for mn, olivine for mg, wollastonite for ca, albite for na and an orthoclase for k). afterwards, standard zaf corrections were applied. approximately 500 spot analyses were carried out. we analyzed 3 to 5 points in each mineral grain, but in the case of zoned crystals, as many as 20– 30 points were analyzed, depending on the number of distinguishable zones. 4. petrography the battonya granitoid has light greenish grey, grey and pinkish grey colours. it is generally medium-grained, equigranular, sometimes with pinkish microcline megacrysts. the majority contains biotite and/or muscovite. three rock types have been distinguished: type i.: quartzmonzodiorite (fig. 2/a, i.) is the greenish grey variety containing amphibole and biotite but no primary muscovite. the chemical composition is mostly metaluminous or slightly peraluminous (fig. 2/b, i.).they are most probably basic enclaves in the prevailing two mica and muscovite granitoid pluton . amphiboles form large euhedral and subhedral crystals or aggregates. the large amphibole is zoned; the core is mgfigure 2: a – rock classifi cation: i. quartzmonzodiorite; ii. granodiorite; iii. granite; (debon et al., 1983). b – a/cnk v. a/nk of battonya granitoids (i. quartz monzodiorite; ii. granodiorite iii.granite; after shand, 1947). geologia croatica 65/2geologia croatica 246 biotite is subhedral, mg-rich (fe/ (fe + mg) = 0.31, table ii.) and al poor (al = 2.84 pfu) with phlogopitic (fig. 3/b, i.) composition, having a calc-alkaline (abdel-rahman, 1994; buda et al., 2004/c) chemical character (fig. 3/c, i.). sometimes biotites occur as anhedral patches in amphibole showing replacement texture. alteration of biotite to chlorite is common. primary muscovite is absent but a secondary variety (sericite) is common in plagioclase. the plagioclases have oscillatory zoning between andesine (an43–40, fig. 3/d) and oligoclase (an17–13) with secondary albitization and sericitization. sometimes unzoned oligoclase (an17–10) can also be observed. a cross-hatched microcline is present but not common; it shows replacement texture without perthitic exsolution and has a low na content (or94, fig. 3/d, insert). quartz is deformed with wavy extinction, and secondary calcite is observed. accessory minerals are acicular apatite, zircon and rare monazite. type ii and type iii: granodiorite and granite (fig. 2/a, ii, iii.). these granitoids are the most common. differences between the granodiorite and granite are not well defi ned because autometasomatism, and hydrothermal processe s obscure the primary rock and mineral compositions (e.g., the k-feldspar/plagioclase ratio). granodiorite-granite is grey with either biotite and muscovite or with muscovite alone, and sometimes contains microcline megacrysts. these rocks are strongly peraluminous (fig. 2/b ii., iii., a/cnk = 1.1– 1.7, cipwavg corundum = 4). in the two mica granitoid the biotite is fe-rich (fe/ (fe + mg) = 0.58, table ii, fig. 3/b, ii.) and strongly pleochroic (γ, = dark brown α, = yellowish brown) with peraluminous (al = 3.02 pfu) compositions (fig. 3/c, ii.) and sometimes entirely altered to chlorite. euhedral or subhedral large primary muscovite is common. sometimes muscovite grew across the biotite (fig. 4/1, 2) indicating later crystallization from an al-rich water-saturated melt . according to miller et al. (1981), al-rich biotite (>3.00 al pfu) coexists with quartz, k-feldspar, and na-plagioclase in peraluminous granite. the plagioclase is sometimes oscillatory zoned. the cores are mostly oligoclase (an25–18, fi g. 5/a) and the rims are albite (an2–0) in the two mica granitoid and the muscovite granitoid, the plagioclases are richer in na (an18–0, fi g. 5/b ). the plagioclase cores are strongly sericitized or altered to clay minerals, partly replaced by cross-hatched microcline and albite. albite and microcline with low na (or95–97) is widespread, occurring in replacement textures. secondary albite also forms vein fi llings. sometimes large primary albite (an3–4) is replaced partly by microcline (e.g. two-mica granite). maximum or nearly maximum microcline (δ = 0.74, buda, 1975) occurs as megacrysts with low na content (or95–98) indicating a low crystallization temperature and slow rate of cooling. quartz is ubiquitous and displays wavy extinction; it also occurs as myrmekite in plagioclase. stubby apatite, zircon, and monazite crystals are common accessory minerals. table i: representative compositions of amphiboles from battonya unit determined by electron microprobe. battonya n-2   1 2 3 4 5 6 7 sio2 46.55 50.61 51.93 51.69 51.02 50.93 52.83 tio2 0.66 0.30 0.27 0.16 0.25 0.22 0.25 al2o3 9.42 5.87 4.85 4.97 5.52 5.90 4.27 feo 11.15 9.23 8.69 8.48 8.90 9.30 8.43 cr2o3 0.20 0.10 0.02 0.07 0.08 0.16 0.00 mno 0.46 0.38 0.35 0.33 0.33 0.37 0.27 mgo 14.56 16.75 17.39 17.38 16.96 16.65 17.31 cao 12.05 12.47 12.67 12.61 12.75 12.59 12.53 na2o 1.34 0.76 0.59 0.73 0.76 0.78 0.54 k2o 0.45 0.33 0.22 0.18 0.21 0.25 0.17 total 96.84 96.80 96.97 96.60 96.77 97.13 96.60 structural formulae calculated on an anhydrous basis of 23 (o) tsi 6.823 7.299 7.434 7.426 7.343 7.316 7.559 tal 1.177 0.701 0.566 0.574 0.657 0.684 0.441 sum_t 8 8 8 8 8 8 8 cal 0.450 0.295 0.254 0.266 0.279 0.314 0.280 ccr 0.024 0.011 0.002 0.008 0.009 0.018 0 cti 0.073 0.033 0.029 0.018 0.027 0.024 0.028 cmg 3.181 3.600 3.711 3.722 3.639 3.565 3.691 cfe2 1.273 1.061 1.005 0.987 1.046 1.079 0.997 cmn 0 0 0 0 0 0 0.005 sum_c 5 5 5 5 5 5 5 bfe2 0.094 0.053 0.036 0.032 0.025 0.038 0.012 bmn 0.057 0.046 0.042 0.040 0.041 0.045 0.028 bca 1.849 1.901 1.922 1.928 1.934 1.918 1.921 bna 0 0 0 0 0 0 0.039 sum_b 2 2 2 2 2 2 2 aca 0.043 0.026 0.022 0.013 0.032 0.019 0 ana 0.381 0.213 0.165 0.203 0.211 0.216 0.111 ak 0.084 0.061 0.041 0.034 0.038 0.045 0.032 sum_a 0.509 0.300 0.229 0.250 0.281 0.281 0.143 sum_cat 15.509 15.300 15.229 15.250 15.281 15.281 15.143 1. core of the large grain. 2. outer zone of a large grain. 3. larger crystal. 4–6. small acicular grains. 7. small acicular grain. hornblende with a low si (6.823 pfu) and high al (1.627 pfu, a/cnk = 0.70), ti (tio2 = 0.66 wt %), and cr (cr2o3 = 0.2 wt %) content (table i.). according to holland & blundy’s (1994) amphibole-plagioclase thermometer, it formed about 700°c and at 440 mpa pressure (anderson et al., 1996). the rim is actinolite (fig. 3/a) which additionally forms small aggregates (a/cnk=0.31–0.45). it probably formed at similar p/t conditions to secondary muscovite . buda et al.: mafi c enclaves in peraluminous variscan granitoid in the battonya unit from southeast hungary geologia croatica 247 table ii: representative compositions of biotites from battonya unit determined by electron microprobe.   biotite coexists with amphibole biotite coexists with muscovite   battonya n-2 average mezőhegyes-5 average   1 2 3 4 5 6 7 8   9 10 11 12 13 14   sio2 38.99 39.17 38.79 37.51 37.90 38.02 38.00 38.21 38.32 34.88 35.49 34.64 34.89 35.09 35.16 35.02 tio2 1.45 1.89 2.16 1.84 1,64 1.98 2.03 2.19 1.90 3.33 3.18 3.51 3.36 3.62 3.56 3.42 al2o3 16.16 16.34 16.12 16.30 16.23 16.33 16.39 16.27 16.27 16.59 16.21 16.70 16.60 16.46 16.22 16.46 cr2o3 0.00 0.00 0.00 0.12 0.14 0.06 0.06 0.04 0.05 0.02 0.01 0.01 0.02 0.00 0.02 0.01 feo 13.44 12.15 12.63 13.41 13.07 12.02 12.19 11.78 12.59 21.46 21.08 21.67 21.32 21.24 21.58 21.39 mno 0.21 0.19 0.16 0.23 0.23 0.22 0.20 0.21 0.21 0.32 0.31 0.35 0.33 0.34 0.29 0.32 mgo 14.68 14.93 14.88 15.20 15.40 15.63 15.74 15.94 15.30 8.64 8.67 8.45 8.52 8.36 8.27 8.49 bao 0.00 0.00 0.00 0.12 0.08 0.15 0.23 0.18 0.09 0.29 0.16 0.23 0.30 0.35 0.31 0.27 cao 0.00 0.04 0.02 0.03 0.01 0.02 0.01 0.01 0.02 0.00 0.03 0.01 0.02 0.00 0.02 0.01 na2o 0.11 0.13 0.09 0.07 0.10 0.09 0.10 0.09 0.10 0.14 0.11 0.14 0.11 0.10 0.09 0.11 k2o 9.90 9.94 9.98 9.24 9.50 9.70 9.79 9.69 9.72 9.57 9.14 9.43 9.52 9.44 9.50 9.43 total 95.94 94.78 94.80 94.08 94.30 94.20 94.74 94.63 94.56 95.23 94.37 95.12 94.98 95.00 95.01 94.95   structural formulae calculated on an anhydrous basis of 22 (o) si 5.778 5.777 5.740 5.619 5.657 5.658 5.634 5.653 5.689 5.420 5.528 5.392 5.431 5.456 5.475 5.450 aliv 2.222 2.223 2.260 2.381 2.343 2.342 2.366 2.347 2.311 2.580 2.473 2.609 2.569 2.544 2.525 2.550 alvi 0.598 0.615 0.550 0.493 0.509 0.519 0.495 0.488 0.533 0.456 0.500 0.452 0.474 0.470 0.449 0.467 ti 0.162 0.210 0.240 0.208 0.184 0.222 0.226 0.244 0.212 0.389 0.372 0.411 0.393 0.424 0.417 0.401 fe2 1.666 1.499 1.563 1.680 1.632 1.495 1.512 1.458 1.563 2.789 2.746 2.820 2.775 2.762 2.810 2.784 cr 0.000 0.000 0.000 0.015 0.016 0.007 0.008 0.005 0.006 0.003 0.001 0.002 0.002 0.000 0.002 0.001 mn 0.026 0.024 0.020 0.029 0.029 0.027 0.025 0.027 0.026 0.042 0.040 0.046 0.043 0.045 0.038 0.042 mg 3.243 3.283 3.282 3.395 3.425 3.467 3.480 3.517 3.387 2.002 2.012 1.960 1.978 1.938 1.920 1.968 ba 0.000 0.000 0.000 0.007 0.005 0.008 0.014 0.011 0.006 0.017 0.010 0.014 0.018 0.022 0.019 0.017 ca 0.000 0.006 0.003 0.005 0.001 0.004 0.001 0.001 0.003 0.000 0.005 0.002 0.003 0.000 0.003 0.002 na 0.032 0.037 0.025 0.021 0.030 0.025 0.028 0.027 0.028 0.042 0.034 0.041 0.034 0.030 0.027 0.035 k 1.872 1.870 1.885 1.766 1.809 1.841 1.852 1.830 1.840 1.898 1.816 1.873 1.890 1.873 1.887 1.873 cations 15.599 15.544 15.565 15.619 15.640 15.615 15.641 15.607 15.604 15.638 15.534 15.619 15.611 15.561 15.572 15.589 fe/ femg 0.340 0.310 0.320 0.330 0.324 0.300 0.302 0.293 0.315 0.580 0.580 0.590 0.583 0.585 0.590 0.585 1. – small crystal with amphiboles. 2–6. –small crystals near to amphiboles. 7–8. – large crystals with amphiboles. 9–14. – large crystals with muscovite sometimes transecting by muscovite. 5. white mica petrography and chemistry we distinguished the primary (magmatic) muscovite from secondary muscovite in order to obtain information of the p/t conditions of crystallization and depth of the intrusion of a mainly peraluminous granitoid melt in the battonya area, where knowledge is limited as these rocks are only studied in drill-cores from 1000–1500 m depth. there are textural and chemical criteria for distinguishing primary (magmatic) muscovite from secondary muscovite (speer, 1984): 1) textural criteria: the grains of primary muscovite are subhedral to euhedral with sharp grain boundaries; grain sizes are similar to those of other, coexisting magmatic minerals. often the textural evidence is uncertain, and chemical criteria are also needed. 2) chemical criteria: the magmatic muscovite is enriched in ti, na, and al and contains lower amounts of si and mg compared to secondary muscovite. primary and secondary muscovites can be distinguished in the granite-granodiorite of the battonya unit based on these criteria. the primary muscovite grains are large, up to a few millimetres in size, with euhedral and subhedral outlines. in the two-mica granitoids they usually grew across biotite (fig. 4./1,2) , and in the muscovite granite they also form large euhedral and subhedral grains with sharp boundaries that clearly separate them from the grain boundaries of neighboring minerals, such as feldspars and quartz (fig. 4./3). the secondary muscovites are smaller than the primary grains geologia croatica 65/2geologia croatica 248 figure 3: a – amphibole composition of quartzmonzodiorite. b-c – plot of biotite composition coexisting with amphibole (i) and muscovite (ii). b – plagioclase and microcline composition of quartzmonzodiorite. (100–250 μm or less), and have subhedral shapes and, in most cases, they occur in plagioclases or microcline as alteration products (fig. 4./4–7), usually together with secondary anhedral albite and microcline . chemically, the primary muscovite (fig. 6) has more ti (table iii, avg.: 0.12 pfu), na (avg.: 0.14 pfu), and al (avg.: 5.21 pfu) and less mg (avg.: 0.20 pfu) and si (avg.: 6.16 pfu) than the secondary muscovite, which has avg.: ti 0.05 pfu, na 0.07 pfu, al 5.06 pfu, mg 0.28 pfu, si 6.28 pfu. a high ti content is a good indicator of primary muscovite because it is not affected by secondary processes such as subsolidus oxidation or exchange of cations (zen, 1988). the mg, fe, na, al, and si contents of the two types of muscovite can overlap according to speer (1984). a very slight enrichment in fe can be observed in the secondary muscovite (fe in secondary: 0.46 pfu; fe in primary: 0.43 pfu). according to monier et al. (1984), the ratio of na/ (na+k) is also a good indicator for distinguishing the origin of muscovite (primary: na/(na+k) = 0.06–0.12; postand late-magmatic: 0.01–0.07; hydrothermal: < 0.04). in the case of the battonya granitoids, primary muscovite has a higher na/(na+k) ratio (0.07) compared to secondary muscovite (0.04, table iii). therefore the primary muscovites can be distinguished from secondary muscovite both texturally and compositionally. textures show that primary muscovite crystallized from the melt after biotite. the secondary muscovite originated by low-temperature hydrothermal processes compared with lateto post-magmatic muscovites. the primary (magmatic) muscovite crystallization was followed by secondary (subsolidus) mica formation as a continuous postmagmatic process during the variscan orogeny. this is also supported by k/ar, sr/rb ages (average white mica age 350–330 ma) published by szederkényi (2001). 6. discussion and conclusion the relationhip of quartzmonzodiorite to the two mica and muscovite granitoid is not clear but it is most probably a basic enclave showing i-type characters e.g. low initial 87sr/86sr330ma ratio (0.7005) and the presence of amphibole. similar enclaves are known in the other variscan granitoids in hungary (mórágy unit) or in the other granitoids of moldanubian zone of the variscan orogenic belt. the average composition of the battonya granite-granodiorite generally corresponds to the composition of the watersaturated peraluminous near eutectic granite melt called “granite low” (fig. 7/a, winkler et al., 1974, clarke, 1992). magmatic cordierite, andalusite was not present due to the water-saturated high pressure melt. the two-mica granite could crystallize according to the following equation: biotite + muscovite + quartz = cordierite (andalusite) + k-feldspar + h2o buda et al.: mafi c enclaves in peraluminous variscan granitoid in the battonya unit from southeast hungary geologia croatica 249 figure 4: 1, 2 – backscattered electron images of coarse, subhedral, clearly terminated primary muscovite [mu(p)] grown across slightly chloritized alrich biotite (bi). 3 – coarse grained euhedral primary muscovite. 4,5,6 – subhedral small grains of secondary muscovite [(mu(s)] in plagioclase (pl). 7 – coarse grained secondary muscovite in plagioclase. geologia croatica 65/2geologia croatica 250 figure 5: plot of plagioclase and microcline composition in two mica (a) and in muscovite granitoid (b). figure 6: composition of muscovite in two mica (a) and muscovite granitoids (b). i, ii. fi elds according to monier et al. 1986. figure 7: a – plot of battonya granitoid in "granite low" system (i. isotherm at 685oc projected on a cotectic surface, ph2o = 500 mpa, an0–14, winkler, 1975). ii. the same system after clarke, 1992. b – possible p/t conditions of crystallization of peraluminous granitoids of the battony unit. experimental phase equilibrium diagram of watersaturated peraluminous granite solidus (i). (johannes & holtz, 1996) and stoichiometric muscovite breakdown curve (ii.), andalusite = sillimanite reaction (r69, richardson, et al. 1969). the possible isobaric cooling path of battonya peraluminous granitoids is shown between the two arrows, (after clarke, et al.,2005). the increasing ƒh2o and high akalsi3o8 increases the stability of muscovite (clemens et al., 1988). muscovite is stable if the an content of coexisting plagioclase is low (albite-oligoclase). at higher an content, the solidus temperature of the granitoid melt is higher, and primary muscovite cannot crystallize as in the case of quartzmonzodiorite. the bulk composition of the two mica and muscovite granitoid and the presence of primary muscovite indicates a low temperature water-saturated “minimum” peraluminous granite melt (fig. 7/a, b). the pressure of crystallization of magmatic muscovite without magmatic andalusite could be 490–600 mpa according to clarke et al. (2005), because below this pressure, magmatic cordierite or andalusite can crystallize instead of or in addition to the muscovite. the p/t conditions correspond to a minimum 15 km depth of crystallization of the intrusion not far from source rocks. in battonya, the temperature of melts were probably higher because of the presence of metaluminous amphibole-biotite quartzmonzodiorite, but the majority of the rock such as the buda et al.: mafi c enclaves in peraluminous variscan granitoid in the battonya unit from southeast hungary geologia croatica 251 ta bl e iii : r ep re se nt at iv e co m po si tio ns o f p rim ar y (m ag m at ic ) a nd se co nd ar y (h yd ro th er m al ) m us co vi te s f ro m th e ba tt on ya u ni t d et er m in ed b y el ec tr on m ic ro pr ob e.   pr im ar y m us co vi te se co nd ar y m us co vi te ba tt .-3 7 m h. -5 ba tt .-6 3   ba tt .-1 2 av er ag e ba tt .-6 3 ba tt .-1 2 m h8 av er ag e si o 2 45 .4 0 45 .3 0 45 .2 2 45 .4 0 45 .1 7 45 .0 2 44 .9 4 45 .1 5 45 .4 8 45 .0 0 45 .1 6 46 .0 1 45 .2 5 45 .1 6 45 .1 6 45 .2 5 45 .9 9 46 .1 1 45 .7 0 46 .6 2 45 .5 9 46 ,1 9 46 .0 3 ti o 2 0, 79 0. 90 1. 11 1. 79 1. 75 1. 77 1. 03 1. 08 0. 88 1. 09 1, 03 1. 16 1. 01 1. 23 1, 15 1. 18 0. 64 0. 65 0. 71 0. 04 0. 80 0. 29 0. 52 al 2o 3 35 .9 3 36 .0 3 31 .9 5 31 .8 0 31 .3 9 31 .5 7 32 .7 4 32 .7 3 31 .3 6 32 .0 3 32 .3 9 29 .6 9 32 .8 4 32 .6 0 32 .2 7 32 .4 9 31 .7 1 32 .4 6 31 .2 7 31 .7 8 31 .2 4 30 .4 7 31 .4 9 cr 2o 3 0. 01 0. 00 0. 01 0. 01 0. 02 0. 02 0. 02 0. 02 0. 01 0. 03 0. 01 0. 03 0. 00 0. 02 0. 00 0. 01 0. 00 0. 01 0. 00 0. 01 0. 01 0. 00 0. 00 fe o 1. 29 1. 12 4. 18 4. 24 4. 16 3. 99 4. 14 3. 95 4. 41 4. 24 4. 06 4. 58 3. 95 4. 06 4. 04 3. 76 3. 62 3. 37 4. 37 3. 31 4. 72 4. 69 4. 01 m no 0. 02 0. 01 0. 01 0. 03 0. 01 0. 01 0. 05 0, 04 0. 06 0. 04 0. 06 0, 10 0. 06 0. 05 0. 05 0. 04 0. 06 0. 05 0. 11 0. 07 0. 02 0. 03 0. 06 m go 0. 53 0. 54 1. 02 1. 03 1. 04 0. 97 0. 95 0. 92 1. 25 1. 00 1. 01 1. 77 0. 97 1. 02 1. 07 1. 01 1. 38 1. 24 1. 41 1. 35 1. 26 1. 49 1. 35 ca o 0. 01 0. 00 0. 00 0. 00 0. 00 0. 01 0. 00 0. 01 0. 01 0. 01 0. 00 0. 01 0. 00 0. 00 0. 01 0. 00 0. 00 0. 01 0. 01 0. 02 0. 02 0. 00 0. 01 n a 2 o 1. 21 1. 18 0. 39 0. 38 0. 38 0. 36 0. 49 0. 52 0. 39 0. 38 0. 50 0. 24 0. 47 0. 42 0. 55 0. 52 0. 25 0. 31 0. 29 0. 17 0. 37 0. 24 0. 27 k 2 o 9. 49 9. 54 10 .8 5 10 .6 2 10 .7 4 10 .8 0 10 .4 1 10 .5 9 10 ,8 5 10 .9 9 10 .5 9 10 .8 0 10 .7 2 10 .8 3 10 .4 1 10 .5 5 11 .1 7 11 .0 2 10 .8 0 10 .5 6 10 .8 0 11 .2 5 10 .9 3 to ta l 94 .6 7 94 .6 3 94 .7 4 95 .2 9 94 .6 7 94 .5 2 94 .7 6 95 .0 0 94 .6 9 94 .8 2 94 .8 2 94 .3 9 95 .2 8 95 .3 9 94 .7 0 94 .8 2 94 .8 1 95 .2 3 94 .6 8 93 .9 3 94 .8 1 94 .6 5 94 .6 8   st ru ct ur al fo rm ul ae c al cu la te d on a n an hy dr ou s b as is o f 2 2 (o ) si 6. 06 6 6. 05 3 6. 18 1 6. 16 6 6. 18 2 6, 16 7 6. 12 6 6. 13 9 6. 22 8 6. 15 8 6. 15 8 6. 32 7 6. 13 8 6. 12 9 6. 15 9 6. 15 8 6. 26 5 6. 23 7 6. 25 3 6. 36 0 6. 24 0 6. 34 0 6. 28 3 al iv 1. 93 4 1. 94 7 1. 81 9 1. 83 4 1. 81 8 1. 83 3 1. 87 4 1. 86 1 1. 77 2 1. 84 2 1. 84 2 1. 67 3 1. 86 2 1. 87 1 1. 84 1 1. 84 2 1. 73 5 1. 76 3 1. 74 7 1. 64 0 1. 76 0 1. 66 0 1. 71 8 su m _t   al vi 3. 72 0 3. 72 3 3. 32 4 3. 25 2 3. 24 1 3. 26 0 3. 38 2 3. 38 0 3. 28 5 3. 32 0 3. 35 9 3. 13 5 3. 38 4 3. 33 9 3. 34 2 3. 36 3 3. 35 2 3. 40 7 3. 29 2 3. 46 5 3. 27 5 3. 26 6 3. 34 3 ti 0. 07 9 0. 09 0 0. 11 4 0. 18 3 0. 18 0 0. 18 2 0. 10 6 0. 11 0 0. 09 1 0. 11 2 0. 10 6 0. 12 0 0. 10 3 0. 12 6 0. 11 8 0. 12 1 0. 06 6 0. 06 6 0. 07 3 0. 00 4 0. 08 2 0. 03 0 0. 05 4 fe 2 0. 14 4 0. 12 5 0. 47 8 0. 48 2 0, 47 6 0. 45 7 0, 47 2 0. 44 9 0. 50 5 0. 48 5 0. 46 3 0. 52 7 0. 44 8 0. 46 1 0. 46 1 0. 42 9 0. 41 2 0. 38 1 0. 50 0 0. 37 8 0. 54 0 0. 53 8 0. 45 8 cr 0, 00 1 0. 00 0 0. 00 1 0. 00 1 0. 00 2 0. 00 2 0. 00 2 0. 00 2 0. 00 1 0. 00 3 0. 00 1 0. 00 3 0. 00 0 0. 00 2 0. 00 0 0. 00 1 0. 00 0 0. 00 1 0. 00 0 0. 00 1 0. 00 1 0. 00 0 0. 00 1 m n 0. 00 2 0. 00 1 0. 00 1 0. 00 3 0. 00 1 0. 00 1 0. 00 6 0. 00 5 0. 00 7 0. 00 5 0. 00 7 0. 01 2 0. 00 7 0. 00 6 0. 00 6 0. 00 5 0. 00 7 0. 00 5 0. 01 3 0. 00 9 0. 00 2 0. 00 4 0. 00 7 m g 0. 10 6 0. 10 8 0. 20 8 0. 20 9 0. 21 2 0. 19 8 0. 19 3 0. 18 6 0. 25 5 0. 20 4 0. 20 5 0. 36 3 0. 19 6 0. 20 6 0. 21 8 0. 20 4 0. 27 9 0. 25 0 0. 28 7 0. 27 5 0. 25 7 0. 30 4 0. 27 5 ca 0. 00 1 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 1 0. 00 0 0. 00 1 0. 00 1 0. 00 1 0. 00 0 0. 00 1 0. 00 0 0. 00 0 0. 00 1 0. 00 0 0. 00 0 0. 00 1 0. 00 2 0. 00 2 0. 00 2 0. 00 0 0. 00 1 n a 0. 31 3 0. 30 6 0. 10 3 0. 10 0 0. 10 1 0. 09 6 0. 13 0 0. 13 7 0. 10 4 0. 10 1 0. 13 2 0. 06 4 0. 12 4 0. 11 1 0. 14 5 0. 13 8 0. 06 5 0. 08 1 0. 07 6 0. 04 4 0. 09 7 0. 06 5 0. 07 1 k 1. 61 8 1. 62 6 1. 89 2 1. 84 0 1. 87 5 1. 88 8 1. 81 0 1. 83 7 1. 89 5 1. 91 9 1. 84 2 1. 89 5 1. 85 5 1. 87 5 1. 81 1 1. 83 2 1. 94 0 1. 90 1 1. 88 5 1. 83 7 1. 88 6 1. 96 9 1. 90 3 ca tio ns 13 .9 84 13 .9 79 14 .1 21 14 .0 70 14 .0 88 14 .0 85 14 .1 01 14 .1 07 14 .1 44 14 .1 50 14 .1 15 14 .1 20 14 .1 17 14 .1 26 14 .1 02 14 .0 94 14 .1 21 14 .0 93 14 .1 28 14 .0 15 14 .1 42 14 .1 76 14 .1 13 n a/ n a+ k 0. 16 2 0. 15 8 0. 05 2 0. 05 2 0. 05 1 0. 04 8 0. 06 7 0. 06 9 0. 05 2 0. 05 0 0. 06 7 0. 03 3 0. 06 3 0. 05 6 0. 07 4 0. 07 0 0. 03 2 0. 04 1 0. 03 9 0. 02 3 0. 04 9 0. 03 2 0. 03 6 m g/ fe m g 0. 42 0 0. 46 0 0. 30 0 0. 30 0 0. 31 0 0. 30 0 0. 29 0 0. 29 0 0. 34 0 0. 30 0 0. 31 0 0. 41 0 0. 30 0 0. 31 0 0. 32 0 0. 33 1 0. 40 0 0. 40 0 0. 36 0 0. 42 0 0. 32 0 0. 36 0 0. 37 7 * ba tt = b at to ny a co re sa m pl es ; m h = m ez őh eg ye s c or e sa m pl e re m ar ks : t w o m ic a gr an ito id s. ba tt -3 7, m h5. m us co vi te g ra ni to id s. ba t63 , b at t12 , m h8. geologia croatica 65/2geologia croatica 252 figure 8: a, b, c – plot of muscovite compositions in the battonya granitoids (arrows show the changing of composition from primary to secondary muscovites). two-mica and muscovite granitoids, crystallized at about 650–6850c and above 490 mpa pressure. afterwards, the granitoids were affected by alkali metasomatism, indicated by the replacement of microcline and albite, and by hydrothermal alteration evidenced by widespread secondary mica and chloritization of biotite. magmatic crystallization, metasomatism, and hydrothermal processes were continuous events in the plutonic rocks as suggested by the continual decrease in ti and na, and the increase in si and mg contents of white micas (fig. 8/a, b, c). the hydrothermal activity increased the a/cnk indices of the granitoids in some parts of the intrusion due to the leaching of alkalis. different rates of hydrothermal alteration caused the wide range of a/ cnk ratios. these alterations are common in the granitoid plutons due to the saturation of water vapour at the temperature of solidus of peraluminous granite melt (clarke, 1992). the origin of the granitoid melts was mixed i and s sources. the absence of andalusite, cordierite and a hornfelsic contact zone indicates a high pressure, low temperature, water-saturated nearly “in situ” crystallization . acknowledgement the project was supported by the hungarian national research fund (otka), no: k-67787. references abdel-rahman, a.f.m. (1994): nature of biotites from alkaline, calc-alkaline and peraluminous magmas.– j. petrol., 35, 525–541. anderson, j.l. & smith, d.r. (1995): the effect of temperature and oxygen fugacity on al-in-hornblende barometry.– am. mineral., 80, 549–59. buda, gy. (1975): classifi cation of the hungarian granitoid rocks on the basis of feldspar investigation.– cbga. proc. xth congress, sec. iii. 67–74. buda, gy. & dobosi, g. (2004/a): lamprophyre-derived high-k mafi c enclaves in variscan granitoids from the mecsek mts. (south humgary).– n. jb. miner. abh. 180/2, 115–147. buda, gy., koller, f. & ulrych, j. (2004/b): petrochemistry of variscan granitoids of central europe: correlation of variscan granitoids of tisia and pelsonian terranes with granitoids of the moldabuda et al.: mafi c enclaves in peraluminous variscan granitoid in the battonya unit from southeast hungary geologia croatica 253 nubicum, western carpathian and southern alps. a review: part i.– acta geol. hung., 47/2–3, 117–138. buda, gy., koller, f., kovács, j. & ulrych, j. (2004/c): compo sitional variation of biotite from variscan granitoids in central europe: a statistical evaluation.– acta min.-petr., szeged, 45/1, 21–37. buda, g., nagy, g., pál-molnár, e. & koller, f. (2009): two main types of variscan granitoids in the tisia composite terrane (hungary).– mitt. österr. miner, ges. 155, p. 39. clarke, d.b. (1992): granitoid rocks.– chapman and hall, 283 p. clarke, d.b. (1995): cordierite in felsic igneous rocks: a synthese.– min. mag., 59, 311–325. clarke, d.b., dorais, m., barbarin, b., barker, d., cesare, b., clarke, g., el baghdadi, m., erdmann, s., förster, h.j., gaeta, m., gottesmann, b., jamieson, r.a., kontak, d.j., koller, f., leal gomes, c., london, d., morgan vi, g.b., neves, l.j.p.f., pattison, d.r.m., pereira, a.j.s.c., pichavant, m., rapela, c.w., renno, a.d., richards, s., roberts, m., rottura, a., saavedra, j., sial, a.n., toselli, a.j., ugidos, j.m., uher, p., villaseca, c., visonà, d., whitney, d.l., williamson b. & woodard, h.h. (2005): occurrence and origin of andalusite in peraluminous felsic igneous rocks.– journal of petrology, 46/3, 44l–472. doi: 10.1093/petrogy/egh083 clemens, j.d. & wall, v.j. (1988): controls on the mineralogy of s-type volcanic and plutonic rocks.– lithos, 21, 53–66. csontos, l. (1995): tertiary tectonic evolution of the intra-carpathian area: a review.– acta vulcanol., 7, 1–13. csontos, l. & nagymarosy, a. (1999): late miocene inversion versus extension in the pannonian basin.– tübinger geowissenschaftliche arbeiten, series a, 52, p. 132. csontos, l. & vörös, a. (2004): mesozoic plate tectonics reconstruction of the carpathian region.– paleogeogr. paleoec. 210, 1–56. debon, f. & le fort, p. (1983): a chemical-mineralogical classifi cation of common plutonic rocks and association.– trans. royal soc. edinburgh: earth sci., 73, 135–149. haas, j., mioč, p., pamić, j., tomljenović, b., árkai, p., bercziné-makk, a., koronkai, b., kovács, s. & felgen kauer, e.r. (2000): complex structure pattern of the alpine-din naridic-pannonian triple junction.– int. j. earth. sci., 89, 377–389. haas, j. & péro, c. (2004): mesozoic evolution of the tisza megaunit.– int. j. earth. sci., 93, 297–313. holland, t. & blundy, j. (1994): non-ideal interactions in calcic amphiboles and their bearing on amphibole-plagioclase thermometry.– cont. mineral. petrol., 116, 433–47. johannes, w. & holtz, f. (1996): petrogenesis and experimental petrology of granitic rocks. minerals and rocks.– springer-verlag, 335 p. kerrick, d.m. (1972): experimental determination of muscovite + quartz stability ph2o< ptotat.– am. j. sci., 272, 946–958. klötzli, u.s., buda g. & skiöld, t. (2004): zicon typology, geochronology and whole rock sr-nd isotope systematics of the mecsek mountain granitoids in the tisia terrane (hungary).– min. petrol., 81, 113–134. doi: 10.1007/s00710-003-0026-0. kovács, s., szederkényi, t., haas, j., buda, gy., császár, g. & nagymarosy, a. (2000): tectonostratigraphic terranes in the pre-neogene basement of the hungarian part of the pannonian area.– acta geol. hung., 43/3, 225–328. kovács, s., buda, gy., haas, j., brezsnyánszky, k. & harangi, sz. (2010): tectonostratigraphic terranes and zones juxtaposed along the mid-hungarian line: their contrasting evolution and relationships.– central european geology, 53/2–3, 165–180. doi: 10.1556/ceugeol.53.2010.2–3.4 márton, e. (2000): the tisza megatectonic unit in the light of paleomagnetic data.– acta geol. hung., 43/3, 329–343. márton, e. (2001): tectonic implications of tertiary paleomagnetic results from the pancardi area (hungarian contribution).– acta geol. hung., 44, 135–144. miller, c.v., stoddard, e.f., bradfish, l.j. & dollase, w.a. (1981): composition of plutonic muscovite: genetic implications.– can. mineral., 19, 25–34. monier, g., mergold-daniel, j. & labernardiére, h. (1984): générations successives de muscovites et feldspaths potassiques dans leucogranite du massif de millevaches (massif central francais).– bull. minéral., 107, 55–68. monier, g. & robert, j.l. (1986): titanium in muscovites from two mica granites: substitutional mechanism and partition with coexisting biotites.– n. jahrb. min. abh., 153/2, 147–161. pál-molnár, e., kovács, g. & batki, a. (2001): petrographical characteristics of variscan granitoids of battonya unit boreholes (se hungary).– acta min.-petrog., szeged, 42, 21–31. richardson, s.w., gilbert, m.c. & bell, p.m. (1969): experimental determination of kyanite-andalusite and andalusite-sillimanite equilibria: the aluminium silicate triple point.– am. j. sci., 267, 259–272. shand, s.j. (1947): eruptiv rocks. their genesis, composition, classifi cation and their relation to ore-deposites. 3rd edition,– j. wiley & sons, new york, 488 p. schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpinecarpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss. j. geosci., 101, 139–183. speer, j.a. (1984): micas in igneous rocks.– in mineralogical society of america.– rev. mineral., 13, 299–356. szederkényi, t. (2001): tisza mega-unit.– in: haas, j. (eds.): geology of hungary. budapest, 148–168. tari, g., dövényi, p., dunkl, i., horváth, f., lenkey, l., stefanescu, m., szafián, p. & tóth, t. (1999): lithospheric structure of the pannonian basin derived from seismic, gravity and geothermal data.– in: durand, b., jolivet, l., horváth, f. & seranne, m. (eds.): the mediterranean basins: tertiary extensions within the alpine orogen. geol. soc. london spec. publ., 156, 215–250. white, a.j.r., clemens, j.d., holloway, j.r., silver, l.t., chappell, b.w. & wall, v.j. (1986): s-type granites and their probable absence in southwestern north america.– geology, 14, 115–118. winkler, h.g.f. & marcopoulos, t. (1975): low temperature granitc melts.– jahrb. min. monatsh., 245–268. zen, e-an (1988): phase relations of peraluminous granitic rocks and their petrogenetic implicatios.– ann. rev. earth planet. sci., 16, 21–51. manuscript received january 23, 2012 revised manuscript accepted may 25, 2012 available online june 29, 2012 www.geologia-croatica.hr 1. introduction the bučim porphyry cu deposit is located in the border area between the serbo-macedonian massif (smm) and the vardar zone (vz). it is an integral part of the bučim-damjan-borov dol ore district located in the eastern part of the republic of macedonia. in terms of its metallogeny, it belongs to the lece chalkidi metallogenic zone (serafimovski, 1990), which is a part of the alpine-balkan-carpathian-dinarides metallogenetic belt (heinrich & neubauer, 2002). the intrusions of the district belong to the late eocene-oligocene magmatic zone (harkovska et al., 1989), which cross cuts older tectonic structures (schefer et al., 2011), and occurs within the circum rhodope unit according to the compilation map of schmid et al. (2013). the late oligocene-miocene intrusions are associated with both economic and uneconomic ore mineralization. although the mine at bučim has been known since ancient times, it was not explored in detail until the 1970’s (serafimovski et al., 2010). in terms of its output and ore reserves, it is a small porhyry deposit. since 1979, 80 mt of the 120 mt estimated reserves (as mineral resources), have been mined, with a production dynamic of 4 000 000 tonnes ore annually and an average ore grade of 0.34% cu and 0.35 g/t au (čifliganec, 1993; serafimovski et al., 1996, 2010; volkov et al., 2010). it should also be mentioned that this is characteristic of all porphyry deposits determined in the border area between the smm and the vz or the lece chalkidi zone. the deposit consists of four ore bodies, three of which are related to porphyry fingers and one is distinguished as a supergene mineralization (čifliganec, 1993; serafimovski & boev, 1996; serafimovski et al., 2010; volkov et al., 2010). the intrusions are of andesitic to trachy-andesitic composition with crystallization ages ranging between 27.5 and 24.9 ma (k/ar whole rock ages) (čifliganec, 1993; serafimovski et al., 2010). various mineralogical and fluid inclusion studies have been undertaken in the district but only a limited amount of data related to the magmatic-hydrothermal history of the system have been published (čifliganec, 1993; serafimovski & boev, 1996; serafimovski et al., 2010; strashimirov et al., 1996; volkov et al., 2010). 2. regional geotectonic and metallogenic setting the metallogeny of the southern balkan peninsula is determined by the geodynamic evolution of the tethys-eurasian abstract the paper presents data about the geology, geochemistry, structure, genesis and specific features of the bučim porphyry cu deposit which is actively mined in macedonia. the porphyry mineralization (0.3 % cu, 0.3-0.5 ppm au) is spatially and temporarily associated with tertiary subvolcanic intrusions of latitic and latitic-andesitic composition. the intrusions occurred during oligo-miocene time (24 to 27 ma), a period of intensive tectono-magmatic and ore-forming processes.. the latest results of this study identify an array of major ore (hypogen) minerals such chalcopyrite, pyrite, magnetite, haematite, cubanite, valleriite, native au and bornite and secon dary enrichment zone minerals (within čukar ore body) including chalcocite, cove llite, tenorite, native cu, malachite, azurite etc. added minerals such as calaverite, krennerite, electrum, petzite and bismuth±selenium minerals (bismuthinite, galenobismutite, krupkaite, friedrichite, emplectite, cosalite, laitakarite and native bismuth) are also present. variations of the δ34s values for the whole bučim ore deposit ranged from +0.2 ‰ to +2.5 ‰ while δ13c‰ and δ18o‰ isotope values ranged from -10.8 to -3.8‰ and from +14.0 to +22.7 ‰, respectively. with regard to fluid inclusions, it was confirmed that beside the pre-dominant gas-liquid, two-phase inclusions, there are also three-phase fluid inclusions (gas + liquid + solid phase). also, recent sr and nd isotope ratios (87sr/86sr 0.70666-0.70741 and 143nd/144nd 0.512487–0.512489) indicate slight contamination of the magmatic products by continental crust material, due to partial melting of the deep parts of continental crust underthrust by collision of continental blocks. the ree data show results that are comparable with high contents of large ion lithophile elements (lile), high ba/nb ratio (116.72-190.72) and depletion in high field strength elements (hfse) and europium negative anomaly (0.68893-0.91251). keywords: bučim, ore deposit, porphyry, republic of macedonia article history: received september 14, 2015 revised and accepted january 05, 2016 avaliable online february 29, 2016 101-119 12 figs. 8 tabs. doi:10.4154/gc.2016.09 porphyry cu mineralization related to the small tertiary volcanic intrusions in the bučim ore deposit, eastern macedonia todor serafimovski1, goran tasev1, sabina strmić palinkaš2, ladislav a. palinkaš3 and lazar gjorgjiev1 1 goce delčev university, faculty of natural and technnical sciences, krste misirkov bb, po. box 201, mk-2000 štip, republic of macedonia (goran.tasev@ugd.edu.mk; todor.serafimovski@ugd.edu.mk) 2university of tromsø, faculty of science and technology, department of geology, dramsvegen 201, n-9037 tromsø, norway, (sabina.s.palinkas@uit.no) 3university of zagreb, faculty of science, department of geology, institute of mineralogy and petrology, horvatovac 95, hr-10000 zagreb, croatia (lpalinkas@gfz.hr) vol. 69/1 102 metallogenic belt (temb), as outlined by janković (1997), and ancient crystalline massifs. the temb formed during post-mesozoic times in the location of the former jurassic tethys palaeo-ocean, situated between the southern continental margin of eurasia on one side, and the african-arabian and indian plate on the other side. the belt extends from the western mediterranean, through the alps and southeastern europe via the lesser caucasus, hindu kush, and tibetan plateau, to burma and northwestern indonesia, where it joins the western segment of the pacific metallogenic belt. the southern balkan peninsula, including the republic of macedonia, is a sector of the central temb (fig. 1). the formation of ore deposits was related to certain chronological stages and geo dy na mic settings: (1) late permian-early triassic intracontinental rifting along the northern bou ndary of gondwana and/or its previously detached fragments; (2) jurassic oceanization marked by the ophiolitic complex; (3) suprasubduction magmatism; and (4) a postcollisional (oroge nic) continental setting and related formation of various base and noble-metal deposits (pb-znag, cu-au, au-as-sb-ti, au-ag) (janković, 1997). the jurassic ophiolite belt extends for hundreds of kilometres within macedonia and for a few thousand kilometres on a global scale via greece, turkey, the caucasus, and iran to the himalayas. in macedonia, the ophiolite complex occurs in the vardar zone (vz) and the adjacent serbo-macedonian massif (smm) (karamata & lo vrić, 1978). the vz extends in a nw-se direction between the smm and the pelagonian massif (fig. 1). ophiolites of the vz comprise the jurassic gabbro-peridotite complex, which is overlain by cretaceous flysch. the smm is located between the carpathian mountains and the balkanides in the east and the vz in the west. dismembered peridotites in the form of pseudodykes occur in the smm along its contact with the vz. the collision of the african and eura s ian plates was accompanied by closure of the ocean and su b duction of the oceanic crust bene ath the smm. deep faults that formed along the active co ntinental margins have important metallogenic implications. the regional te cto nic units listed above, extending parallel to the vz, control regional metallogenic zones, ore districts, and ore fields (fig. 1). colli sion, post-collision processes, and tertiary magmatism were crucial for localization of the base-metal ore mineralization (janković, 1997; serafimovski et al., 2010). cenozoic reactivation embraced largely the eastern part of the macedonian arch and was expressed in the development of the nw-trending faults oriented obliquely to the vz and the transverse ne-trending faults at the final stage (tomson et al., 1998; volkov et al., 2006). the rocks of the tertiary volcanic-plutonic complex and related base-metal mineralization occur in four tectonic and metallogenic zones (fig. 1): (1) figure 1. regional location of the lece-chalkidiki and besna kobila-osogovo-thassos metallogenic zones and area of interest (modified after serafimovski, 1990). serafimovski et al.: porphyry cu mineralization related to the small tertiary volcanic intrusions in the bučim ore deposit... 103 the magmatic zone at the mobile northern, northeastern, and eastern margins of the dinarides (mala kropa, srebrenica, boranja, golija, zeljin, rogozna; pamić & jurković, 1997; janković, 1997); (2) the magmatic zone in the severely tectonized central part of the vz (kopaonik, bukulja, avala, cer, kožuf; janković, 1997; janković et al., 1997); (3) the lece-chalkidiki metallogenic zone at the contact between smm and vz (zletovo, plavica, bučim, borov dol, damjan, borović; serafimovski, 1993; serafimovski et al., 2000); (4) the besna kobila-osogovo metallogenic zone (sasa, toranica, kadica, ilovica; serafimovski, 1990). the precambrian metamorphic complex is the oldest in the smm (fig. 1). the complex is composed of biotite, muscovite, (two-mica), and gneisses, amphibolites, muscovite schists, and other kind of metamorphic rocks. gneisses are widespread and favourable for the localization of ore. palaeozoic rocks comprise chlorite-amphibole schists, slate-carbonate group, metagabbro, and dolerite, which are less favourable for the localization of porphyry ore than the precambrian rocks. the mesozoic formations combine jurassic ultramafic and granitic rocks. serpentinized peridotites and pyroxenites are locally ove rla pped by volcanic flows and quaternary sediments. granite, granodiorite, and quartz monzo nite are accompanied by low-grade chalcopyrite mineralization. palaeogene sedimentary rocks (con glomerate, tuffaceous flysch, limestone) are cut through by neogene subvolcanic intrusive bodies. these rocks, especially marlstone and shale, are favourable hosts for porphyry and skarn mineralization; they serve as screens for ore-bearing fluids and protoliths for metasomatic alteration. neogene conglomerate, gravelstone, sandstone, limestone, and other sedimentary rocks are overlapped by quaternary clayey and sandy sediments (fans, hillside, and alluvial facies) (e.g. dumurdžanov et al., 2004). three variably oriented fault systems are recognized: the first nw-trending fault system coincides in the strike of the major tectonic units; while the second and third systems extend in the northeastern and meridional directions, respectively. the third system has important implications for the develop ment of ter tiary magmatism and related iron skarn and porphyry cu mineralization. this system controls numerous volcanic domes and necks localized at intersections of nearmeridional and northeastern faults. volcanic activity progressed from the beginning of the late oligocene, and ore mineralization formed in miocene times (serafimovski et al., 2010). 3. bučim-damjan-borov dol ore district the bučim-damjan-borov dol ore district with porphyry cu and iron skarn minerali za tion occupies the southwestern part of the lece-chalkidiki metallogenic zone and is about 50 km2 in size. the ore mineralization is concentrated in the bučim, damjan, and borov dol ore fields (fig. 2). several nw–se striking thrust faults divide the district into different te cto nic units (fig. 2, see hristov et al., 1973). the aforementioned thrust faults are related to early miocene crustal shortening, which led to about 800 m of uplift of the bučim region in the borov dol area, which in turn is uplifted 800 m relative to the area located to its west (based on field observations, there are different exposure levels between bučim and borov dol, fig. 2b). the preservation of eocene strata decreases towards the ne due to erosion. therefore, deeper geological units, such as palaeozoic schists and precambrian gneisses, are increasingly exposed towards the ne (fig. 2). numerous intrusions are found in the area, among them the bučim, damjan, borov dol and black hill intrusions. after the emplacement of the porphyry intrusions, a later period of thrust faulting led to uplift of the bučim area in contrast to the borov dol–damjan region (figs. 1, 2, 3). several andesite/trachyandesite intrusions, which are embedded in the volcanic tuffs, host the borov dol cu mineralization (čifliganec, 1993; serafimovski et al., 2010), which offers a view into a shallow magma chamber. it is located 8 km ssw of bučim also in the circum rhodope belt. čifliganec (1993) dated the bučim andesites by k–ar whole rock methods and they yielded ages between 27.5 and 24.9 ma and the damjan and borov dol andesites range in age from 28 to 26.5 ma. the faults in the area mostly trend nnw–sse and nne– ssw, and the distribution of the intrusions largely follows them (serafimovski & boev, 1996). the bučim ore field is localized in the northern part of the ore district within the smm and is characterized by (1) nw and ne-trending low-order faults; (2) prevalence of latite and tra chy-latite dykes and minor intrusions as products of tertiary volcanism; and (3) porphyry cu mineralization. no volcanic domes or calderas expressed as landforms are known. only small ring structures, a few hundreds of metres 1.5 km in diameter accompanied em p l a cement of the subvolcanic stocks. the outer parts of such structural forms are composed of gneiss, whereas the inner parts are composed of latitic stocks. similar structural forms are wi de spread elsewhere in this ore district. in addition to the bučim deposit, numerous po rphyry cu-occurrences are known in the north of the district (vranjak, crn-vrv-kalapetrivci etc.). the damjan ore field is localized in the southeastern part of the ore district at the contact between the damjan horst and the vardar zone and is characterized by (1) nw-se, nnwsse, ne-sw striking fault structures; (2) prevalence of jurassic ultrabasics, palaeogene flysch sediments, tertiary volcanics and newly formed metasomatic products, skarns; and (3) fe-skarn mineralization. the intrusions are of variable size and created diverse host rocks of different tectonic units. the damjan fe-skarn deposit is located about 4 km south of bučim and is one of the rare skarn deposits, which formed at the contact between the andesite and palaeogene flysch. mineralization itself is hosted by skarns and is represented by rich magnetite-haematite parts (>40% fe). the borov dol ore field is localized at the margin of a volcanic caldera in the southern part of the ore district within the vz. the caldera, 5 km in diameter, is clearly expressed in topo gra phy and complicated by several volcanic domes and depressions 1.0-1.5 km in diameter. one of these depressions hosts the borov dol deposit. the nw-trending faults control the neo gene latite and quartz latite dykes, necks, and extrusions. the borov dol deposit is related to this volcanic-plutonic complex. the ore-bearing volcanic rocks are metaso matically altered. the volcanic rocks belong to the high-k shoshonitic series and correspond to monzodiorite and monzonite vol. 69/1 104 in k2o-sio2 discrimination. these are andesite, latite, trachyte, and rhyolite, inclu ding transitional varieties (serafimovski et al., 2010; lehmann et al., 2013). it is worth mentioning that the rocks of the shoshonitic series are typical of districts with porphyry cu mineralization at continental margins, e.g., bajo alumbrera, gunumba, bingham, ok-tedi, grasberg, cadia, etc. (müller & groves, 2000; blevin, 2002). 3.1. general features as previously mentioned the bučim deposit, located in the northeast of the ore district (fig. 2), has been reco gnised since ancient times, but was only explored in detail in the 1970s. about 80 mt of ore have been extracted, with an average grade of 0.34% cu and 0.35 g/t au, from the 120 mt ore reserves, as determined in 1979. the annual exploitation capability of the mine is 4 mt of ore. at present, ore with 0.21 % cu, 0.2 g/t au, and 0.8 g/t ag is being mined. about 32 000 t of concentrate containing 18-21 % cu and 18 g/t au (au recovery is 50%) has been produced and delivered by trucks to smelters at bor in serbia and pirdop in bulgaria. at the moment, the bučim mine is owned by the solway investment group limited. the bučim deposit is likely the world’s smallest deposit of this type currently operated as a mine. the successful mining of this deposit for many years refutes the popular opinion that the porphyry cu deposits profitable for mining must contain no less than 2.5 mt of cu metal and the cu grade in ore should be higher than 0.5% (serafimovski et al., 2010). 3.2. geology of the deposit the first written data about the geological setting of the bučim area can be found in the works of cvijić (1906, 1924) followed by publications by bončev (1920), petunikov (1940, 1944), pavlović (1939) and others. the geological setting of the immediate surroundings of the deposit includes the following end members: 3.2.1. precambrian metamorphic complex this is the most domimant geological unit in the area and is represented by its heterogenous lithological composition. such a lithological heterogenity resulted from the fact that the primary accumulation of sedimentary and magmatic rocks was subjected to regional metamorphism as well as to later retrograde processes, the influence of precambrian granitoid magmatism and figure 2. a: geological map of the bučim-damjan-borov dol ore district, modified after an unpublished mine map of hristov et al. (1973); b: schematic cross section through the bučimdamjan-borov dol ore district (modified by lehmann et al., 2013). serafimovski et al.: porphyry cu mineralization related to the small tertiary volcanic intrusions in the bučim ore deposit... 105 jurassic granitoid magmatism associated with a progressive abakuma type of metamorphism and finally the influence of hydrothermal processes related to the tertiary magmatism (petković, 1966; petković et al, 1968; dumurdžanov et al., 1969; culev et al., 1970). gneisses are the most widespread rocks in both the broader and immediate areas around the deposit. according to their mineral composition, several fa cies can be discriminated (which mutually replace each other): biotite gneisses, amphibole-biotite gneisses, muscovite gneisses, two-mica gneisses, and metasomatic (leuco cratic) gneisses. during the exploitation of the central part of the ore body, the variability in chemi cal composi tion of the gneisses was determined more accurate ly. they consist of bands of mica (biotite and muscovite) alternating with quartz bands. garnet occurs as the dominant mineral besides quartz, biotite and muscovite. apatite is an accessory mineral. mica-schists represent a normal lithological member of the crystalline schists in which they occur as an inte rstratified facies. consequently, they are of the same metamorphic age. from the aspect of mineralization, they represent an unfavourable environ ment, compared with the gneisses, being poorly per meable for hydrothermal solutions. amphibolites occur in the crystalline schists in the form of lenses or strata and larger irregular mas ses. generally, they are concordant to the crystalline schists and at places depart from their folia tion. they are characterized by their dark green colour and shaly texture. 3.2.2. palaeozoic magmatic rocks they occur in the form of small lenses dis tributed along clearly pronounced ruptures. so far, the following have been recognized (culev, 1970): amphibolites, fine-grained rocks of a thin banded texture, which represent an unfavourable environment for deposition of the cu mineraliza tion. they are composed of hornblende, plagioclase, and partly, foliated biotite and chlorite aggregates (ivanov, 1982; čifliganec et al., 1993). serpentinites occur north of the vršnik orebody. they have significant size and thickness (about 10 m), and are distributed along the rupture zone. serpentinites, although grouped into the palaeozoic age, are more probably of jurassic age and represent the remaining parts of the vardar-lzmir ocean. their position along the rim of the serbo-macedonian massif can be explained by diapiric and/or tectonic intrusion. such serpentinite dykes (in the form of stratified series, sometimes even subparallel) occur in the vicinity of porphyry deposits at chalkidiki, greece (serafimovski, 1990). finegrained to po rphyroid gabbros are very compact, dark green to black. their structure suggests their veined character and peripherial position within the in trusive massif. 3.2.3. tertiary volcanic rocks tertiary magmatic rocks played an important role in the geological setting of the bučim deposit (majer, 1958; karamata 1983; čifliganec, 1987, 1993; de nko vski et al., 1983; denkovski & bandilov, 1985; serafimovski 1990; 1993; stojanov & serafimovski, 1990; stojanov & boev, 1993; boev & yanev, 2001). they occur as minor intrusives within the precambrian meta mo rphic co mplex. during the neogene, tectonic and magmatic processes resulted in widespread magmatism. at the pre sent ero sion level it is represented by sub-volcanic and volcanic facies of latite and andesite in the form of dy kes and necks. in the intrusive level the rocks range in co mpo si tion from quartz diorite to granodiorite. in terms of chemistry, they belong to calk-alka line and alkaline affinity. at later stages, they were enriched in potassium. the ore deposition is genetically co nne cted to the emplacement of tertiary, oligocene-miocene subvolcanic latitic and latite-ande sitic bodies within precambrian metamorphic rocks-gneisses, micashists, and amphi bolites (27.5–24.5 m.y., serafimovski, 1993, or 24.5– 24.0 m.y., lehmann et al., 2013). 3.3. ore mineralization the bučim deposit is composed of a magmatic complex consisting of three proven fi n ger-like porphyry stocks (central part, vršnik and bunardžik) while the čukar ore body, a su pergene mineralization developed in gneiss, has already been mined out (čifliganec, 1993, figure 3). the morphology of the čukar orebody was closely related to the structural-textural features which controlled penetration of the descedent solution responsible figure 3. geological scheme and cross section through the bučim ore deposit (serafimovski & boev, 1996). vol. 69/1 106 for supergene processes on the primary ore mineralization. the shape of the orebody resembles a lense stri king northsouth, while the thickness of the supergene sulfide ore-bearing zone does not exceed 60 m (the ab solute height of the supergene mineralization was between 645-505 m a.s.l.). the length and width of the ore body were 400 and 200 m, respectively. according to new geo lo gical field obse rva tions a magmatic stock is assumed to sit below the čukar ore body (personal communi ca tion with local mining geologists; figure 3a). unfortunately, drill cores are now unavailable and the pile of waste from the open pit has accumulated on the remains of the body. the mineralization of the central ore body porphyry is cut by the vršnik intrusion. this relationship is visible in mineralized gneiss clasts, which contain veins that are cut off by the magmatic intrusion. accordingly, the central intrusion is older than the vršnik intrusion (figure 3b). the central part ore body is emplaced in various precambrian gneisses of the circum-rhodope unit. the morphology of the ore body, conformable with the intrusion (stock) almost isometrically on plane, resembles reverse or trun cated cones emplaced mutually into each other (with a diameter of 500 m, surrounding an andesitic stock with a vertical depth of more than 500 m, see fig. 3b). the interior cone has smaller angles of overlap of the conical surfaces, while the outer cone, in relation to the andesite intrusion, is more inclined. the cu mineralization is primary (hypogene). the most significant ore mineral is chalcopyrite, which is accompanied by pyrite, magnetite, haematite, cubanite, valerite, native au, bornite and others (serafimovski & boev, 1996). gneiss xenolithes in the magmatic stock contain pyrite in veinlets, which are cut through by the magmatic intrusion. therefore, the present magmatic rock overprints an earlier magmatic and hydrothermal event. the bunardžik ore body (fig. 3) shows the same mineralization as the central part ore body, but the ore-minerals are scarcer (čifliganec, 1993). the mineralization of the bunardžik ore body is hosted by precambrian gneisses. in contrast to the central ore body, however, the bunardžik ore body is crescent shaped adjacent to the andesitic intrusion and far from being symmetrical in relation to the andesite intrusion. the angles of dip of the outer surfaces outlining the orebody are smaller than the angles of the dip of the contact andesite intrusion. the andesite intrusion, also non-mineral ized, is situated outside the orebody (figure 3). the morphology of the bunardžik orebody is mostly affected by the posi tion of the andesite intrusion. on plane, the bunardžik orebody resembles a horse-shoe positioned around the southern part of the andesite intrusion emplaced in gneiss. the dimensions of the body are 300 × 100 m at the surface with a 300 m depth (čifliganec, 1993). the vršnik ore body (figure 3), which is located east of the central ore body, is ellipsoidal in shape. in contrast to the afore-mentioned bodies, emplaced into gneiss, the vršnik orebody features mineralization chiefly hosted by the intrusions (andesite) and partly by the gneiss (figure 3). in cer tain places, this is a single unique orebody, while elsewhere two parts can be distinguished. this orebody stretches over an interval of about 80 m (at the absolute height of 680-600 m). its longer axis, in the n-s direction is 300 m long, while the width of the orebody centres around 200 m. the given parameters indicate that this orebody is very small in size (čifliganec, 1993). 3.4. analytical methods the numerous enclosed analytical data of samples from the central ore body in the buchim mine are taken between mine levels 680-560 m and ocassional samples from the vršnik ore body between levels 685-650 m. the whole rock analyses (n=14) for major elements were carried out on li-tetraborate pellets (lithium-tetraborate with a 1:5 mixture of claisse m4 fluxer) using the x-ray fluorescence method (xrf; institute of geochemistry and petrology; eth zürich). trace element and ree determinations were conducted, also at the eth zürich, with laser abla tion-inductively coupled plasma-mass spectrometry (la-icp-ms) on the same li-tetra borate pellets and on the zircon grains. the machine is equipped with an excimer laser (arf 193 nm) and a pe sciex elan 6100 drc icp-ms. the spot size of the laser was 40 μm, and for calibration the nist 610 sta n da rd was used (günther et al., 2001; halter et al., 2004). isotopic analysis for sr and nd (isotopic composition of sr and nd and rb, sr, sm and nd concentrations) was mea su red at eth zürich using a tritonplus mass spectrometer (thermal ionisation mass spe ctro metertims) and at the royal holloway university of london (rhul) using a vg354 tims with five movable faraday cups and a daly detector and ancilliary clean preparation laboratories. quantitative elemental analyses of the most interesting ore mineralization samples were pe r f o rmed under a jeol jxa8200 electron probe micro-analyser wd/ed combined micro a na lyser (equipped with a seand bse-detector, fivewds crystal spectrometer and an eds analyser) in the analytical facilities at the institute of geochemistry and petrology, eth zürich, switzerland. the selected electron beam condi ti ons were a beam current of 20 na at an acceleration voltage of 15 kv. an optima dual inlet mass spectrometer was used with the following preparation systems attached to it: laserprep, de si gned and built at rhul for laser heating of minerals in an atmosphere of brf5 to release oxygen for the measurement of 18o/16o and 17o/16o ratios and fisons (ncs ea1500 series 2), an ele me ntal analyser for flash co mbu stion of rocks, soils and vegetation in an oxygen atmo sphere to release co2, n2 or so2 for isotopic analysis. with regard to δ13c and δ18o, syngenetic calcites were analyzed, while δ34s analysis was performed on hypogene sulfides (chalcopyrite, pyrite ±galena). fluid inclusion studies were conducted at the geological department of the royal holloway university of london in the uk, on samples of doubly polished transparent wafers of quartz and calcite (150 μm thick), where for each sample, at least 20 inclusions were analysed. microthermometric data were obtained using a li nkam thmsg600 heating-freezing stage (temperature range –196°c to +600°c) and tms 90 controller attached to a conventional petrographic microscope (nikon and olympus bx51). the stage was calibrated using the synflinc synthetic fluid inclusions (pre ci s i on ± 0.1°c for freezing runs and ± 5°c for temperatures near to or higher than 360°c). fluid inclusion homo genization temperatures serafimovski et al.: porphyry cu mineralization related to the small tertiary volcanic intrusions in the bučim ore deposit... 107 were measured at least twice. the second measurement was carried out at a slow rate (4°c step per minute) close to the last 20°c approaching the previous mea su rement of homogenization temperature. 3.5. ore mineralogy more than three decades of study of this deposit have shown that it is characterized by a complex mineral assemblage and mineral paragenesis. numerous authors have studied the mine ral association in the bučim deposit: ivanov & jasmakovski (1970), zarić (1974), pa vi čević & rakić (1983), nevenić (1984), čifliganec (1987), serafimovski (1990, 1993); sera fi mo vski et al. (1990); čifliganec et al. (1997), tasev (2003); serafimovski et al. (2006); volkov et al. (2010); serafimovski et al. (2013); lehmann et al. (2013) etc. a wide variety of minerals have been recognized in the bučim deposit – both ore bearing and gangue minerals (fig. 4). the mineral composition of orebodies explored so far does not substantially differ, although there are certain peculiarities in the mineral assemblages. the major ore mineral is chalcopyrite accompanied by pyrite, magnetite, haematite, cubanite, valleriite, native au and bornite. the ore mineralization in the central part, in the bunardžik and vršnik ore bodies, in terms of mode of occurrence, mineral composition, association of elements, etc., is very similar. differences can be seen only in the čukar ore body. the čukar ore body is a typical example of supergene mineralization in the deposit characterized by the increased grade of cu but low ore reserves. the major ore minerals are chalcocite and covellite always accompanied by pyrite, tenorite, rarely native cu, malachite, azurite etc. titanite, rutile, magnetite, haematite, chalcopyrite, pyrite, bornite, native au, molybdenite, petzite, calaverite, and argentite were identified as ore minerals. enargite, tetrahedrite, galena, and sphalerite are less abundant. the ore mineralization was formed in the following sequence: titanite, rutile, and magnetite crystallized first, followed by pyrrhotite, cubanite, valleriite, and the early generation of chalcopyrite. after deposition of these minerals, the hydro thermal ore forming solution became enriched in sulfur, giving rise to pyrite crystallization. the late chalcopyrite and galena formed as the final stage of ore deposition (serafimovski, 1993). the recent ore microscope study and electron microprobe analyses have revealed that in the bučim deposit, in addition to the previously identified minerals of native au and its tellurides (calaverite and krennerite (serafimovski et al., 1992; serafimovski et al., 2006), electrum and petzite also occur (table 1; fig. 5). gold content, within coarse-grained chalcopyrite, even in single grains of native au show a large variation, ranging from 80% up to 92% au (jeol jxa-8200 electron probe; eth zürich). the content of au within a single native au grain may vary from 80.30% in the rim, up to 86% au in the central part of the grain. it reflects changes in the physicochemi cal conditions within the hydrothermal fluids during the mineralization. the most common form of au is as native au, electrum and petzite. certain bismuth±selenium minerals (bismuthinite, galenobismutite, krupkaite, friedrichite, emplectite, cosalite, laitakarite and native bismuth) were also identified (table 1; jeol jxa-8200 electron probe; eth zürich). bismuth-selenium minerals (containing 41.7-99.5% bi and 0.3-13.4% se) appear figure 4. diagram of mineral successions that genetically belong to the bučim porphyry hydrothermal cu-deposit. vol. 69/1 108 a) d) b) e) c) f) to be characteristic of the au-bearing mineralization of the bučim cu porphyry deposit. selenium is not common in the early paragenesis, whereas it is present in krupkaite up to 1.1% se, emplectite 1.9-2.5% se, while its highest concentration was determined in laitakarite at 13.5% se. it is quite possible that during the deposition of laitakarite an influx of se occurred in the hydrothermal solutions. within the second ore paragenesis, which also contains particular amounts of bismuth, there are significant amounts of silver up to 5.0% ag, as well as low amounts of selenium, 0.3% se. the most common mineral in the bučim porphyry cu deposit is pyrite present at 3%, while chalcopyrite is the ma jor be a rer of cu mineralization with a presence of 1%. the aupd association has been determined within the pyrite and chalcopyrite of the major ore-bearing phase in the central part orebody. the studied pyrites belong to four different generations and increased concentrations of au and pd were determined in the so-called blocky pyrites or massive py rites. the latest microscope and micro probe study have de te rmined two main mineral assemblages: magnetite-py rite-chalcopyrite (mt-py-cp) and pyrite-chalcopyrite (py-cp), as the major hosts of au and pd. the high degree of geo che mical correlation between au, pd and as in py rite and chalcopyrite figure 5. .electron microprobe photographs of au and bi-se minerals from the bučim deposit: a) electrum (white) in chalcopyrite (dark grey), x182; b) petzite (white-whitegrey) in cha lco py rite (dark), x401; c) laitakarite-emplectite (whitegrey) in hydrothermally-altered rock (dark), ba cksca ttered electron image, x300; d) bismuthinite (white) along chalcopyrite (grey) in hydrothermally-altered rock (dark), x600; e) zoned aikinite-bismuthinite aggregate (grey) hosting galena (white) tri angular form, x3000; f) needle-like cosalite crystals, scanning electron microscope. x301. table 1. quantitative microanalyses of newly determined bi, bi-se and au±te minerals in the bučim deposit. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 bi (%) 99.52 97.43 78.32 79.83 54.67 52.92 55.38 61.65 64.81 41.69 42.63 80.11 pb (%) 0.18 1.62 26.64 20.68 21.05 33.38 30.03 2.21 cu (%) 0.42 0.47 1.82 0.92 6.28 6.55 15.06 13.9 9.5 1.26 0.52 au (%) 72.53 26.84 ag (%) 0.99 1.59 4.96 0.7 fe (%) 1.14 1 01 1.9 1.07 0.68 as (%) 0.32 25.42 41.09 se (%) 1.12 1.85 2.57 0.26 13.41 te (%) 1.1 31.23 s (%) 19.17 17.26 18.42 17.53 17.71 18.42 15.9 16.84 17.2 34 σsum 99.7 98.99 99.58 99.92 100.75 99.75 100.69 99.87 99.84 97.13 100.06 99 93 99.89 99.68 1. native bismuth; 2. native bismuth; 3. bismuthinite; 4. bismuthinite; 5. galenobismutite; 6. krupkaite; 7. krupkaite; 8. emplectite; 9. emplectite; 10. cosalite; 11. friedrichite; 12. laitakarite; 13. electrum; 14. petzite. serafimovski et al.: porphyry cu mineralization related to the small tertiary volcanic intrusions in the bučim ore deposit... 109 points to a wide range of physico-chemical conditions and the inter play between ma gma tic and hydrothermal processes during formation of the deposit. the au-pd phase occurs as a separate mineral phase, which is disti ngu ished by a special colour (pink grey; fi g . 6a). the au content in the studied pyrite is within the range of 0.12– 7.54% au while the pd content is within the ra nge 0.01–6.33% pd, and they are presented as a special mixture of mineral phases characterized by their gray colour (figure 6a; table 2). increased concentrations of au-pd in chalcopyrite are related to the massive, medium-to-high temperature, coarsegraind chalcopyrite, which constitutes the major ore phase within the bučim deposit (table 2). ho we ver, as in chalcopyrite shows lower values here compa red to those in pyrite. the inc r ea sed content of pd as well as pd-minerali zation in the cu-au ores of the deposit in bučim, macedonia has also been determined in bor-ma j da npek, se r bia (janković, 1990), skouries, greece (tarkian et al., 1991; eco no mouelio po ulos, 2010), and ela tsite, bulgaria (petru nov et al., 1992), wh ere the cu-po rphyry style of hydrothermal pge has also be en observed. platinum concentrations were determined only as trace amounts. 3.6. stable isotope data 3.6.1. sulfur isotope composition data sulfur isotope compositions (δ34s ‰) normalized to the canyon diablo meteorite (cdm, δ34s=0.0‰) show a narrow range of variance from +6 ‰ to –4 ‰, po inting to a sulfur origin from the upper mantle, (the fractionation sulfur which has ori gi nated from the upper mantle or deep homogenized parts figure 6. a) electron microprobe photograph of pyrite (dark) and au-pd phases (light grey) and b) electron microprobe photograph of chalcopyrite, with point analysis. a) b) 1 2 3 4 5 6 7 8 9 10 11 12 au (%) 6.98 0.21 7.75 6.51 0.12 7.54 6.34 0 6.46 0.29 9.1 7.29 fe (%) 39.29 43.64 39.18 39.98 45.46 43.56 25.92 29.08 25.13 29.11 25.97 25.73 s (%) 44.65 53.93 46.17 44.4 53.53 47.34 28.74 34.32 29.74 33.6 26.96 28.64 cu (%) <d. l. <d. l. 0.03 0.02 0.06 0.01 29.46 33.68 28.68 33.51 26.64 28.91 as (%) 0.16 <d. l. 0.03 0.68 0.14 0.02 <d. l. 0.02 0.05 <d. l. 0.05 0.01 ag (%) <d. l. <d. l. <d. l. 0 0 0.73 <d. l. <d. l. <d. l. <d. l. <d. l. <d.l. pd (%) 6.64 0.01 6.02 5.65 1.23 0.04 7.38 0.02 8.11 0.3 7.97 6.81 ge (%) 0.31 0.45 0.25 <d. l. <d. l. 0.21 0.22 <d. l. <d. l. 0.38 0.42 0.35 zn (%) 0.42 0 0.26 <d. l. <d. l. <d. l. 0.35 <d. l. <d. l. 0.44 0.36 0.41 v (%) 0.53 0.25 0.21 0.21 <d. l. 0.22 0.38 0.37 <d. l. 0.42 0.44 0.45 ni (%) 0.24 0.67 0.15 <d. l. <d. l. 0.21 0.33 <d. l. <d. l. 0.35 0.41 0.48 se (%) 0.09 0 <d. l. 0.52 <d. l. <d. l. <d. l. 0.33 0.22 <d. l. <d. l. <d. l. bi (%) < d.l. <d. l. <d. l. 0.65 <d. l. <d. l. <d. l. 0.42 0.31 <d. l. <d. l. <d. l. te (%) <d. l. <d. l. <d. l. 0.39 <d. l. <d. l. <d. l. 0.35 0.25 <d. l. 0.22 <d. l. σ sum 99.07 99.16 100.04 99.01 100.55 99.88 99.12 98.59 98.94 98.4 98.53 99.08 table 2. electron microprobe analyses of pyrites and chalcopyrites from the bučim cu porphyry deposit. note: 1-6. electron microprobe analysis data of pyrite; 7-12. electron microprobe analysis data of chalcopyrite; <d. l. below detection limit. vol. 69/1 110 of the earth’s crust varies within narrow range of ±10‰ compared with the cdm standard, (jensen,1959; sakai, 1968; grinenko & grinenko, 1974; janković, 1981; shelton & rye, 1982; andrew et al., 1989; and others). a preliminary study performed on 10 pyrite samples was done by mudrinić & pe tko vić (1974). preceeding analyses confirmed the general trend of sulfur isotope values (tasev, 2003; sera fi mo vski & tasev, 2005). sulfur isotope composition of the pyrites show little variation, with a slight increase of the heavy sulfur isotope v the meteoritic one (table 3). variations of the δ34s values for the whole bučim ore deposit were in the range of +0.2 ‰ to +2.5 ‰, with an average value of +1.0 ‰ (fig. 7). there is some variation in the δ34s values for particular ore bodies. the variation in the δ34s values for the different ore bodies was probably caused by the small differences in fracionation grade due to the slight changes of physico-chemical conditions of the ore fluids along the mineralization path. 3.6.2. carbon and oxygen isotope composition determination of the origin of the water in hydrothermal solutions relies mainly on data from oxy gen fractionation. isotopic compositions of carbon 13c/12c and oxy gen 18o/16o were analyzed in calcite samples taken from the central part and čukar ore bodies (table 4). the results show narrow ranges for both isotopes, carbon and oxygen, from -10.8 to -3.8‰ and from +14.0 to +22.7 ‰, respectively. a uniformity in their values, suggests fractionation and a change of the primary isotope compositions of carbon and oxygen from a homogeneous source within a wider porphyry complex. 3.7. fluid inclusions data study of fluid inclusions (blečić, 1974; strashimirov et al., 1996, palinkaš et al., 2008) in quartz from the no. ore body horizon δ34s‰ 1 čukar 630 +2.5 2 čukar 630 +0.2 3 čukar 630 +1.0 4 central ore body 605 +1.5 5 central ore body 605 +0.4 6 central ore body 605 +0.7 7 vršnik 650 +0.0 8 vršnik 650 +0.4 9 vršnik 650 +0.8 10 vršnik 650 +2.1 11 central ore body 590 +1.0 12 central ore body 590 +1.2 table 3. isotopic composition of sulfur in minerals from the bučim ore field. figure 7. a) frequency distribution of sulfur isotope values for sulfides from the bučim cu-porphyry deposit and b) sulfur isotope values in particular ore bodies at particular mine levels. a) b) table 4. isotopic composition of d13c (pdb) and d18o (smow) in calcite from the ore bodies in the central part and čukar. no. sample mineral δ13c‰ δ18o‰ 1 central ore body calcite -10.4 +17.6 2 central ore body calcite -7.8 +22.6 3 central ore body calcite -6.9 +18.9 4 central ore body calcite -6.4 +20.5 5 central ore body calcite -5.8 +21.4 6 central ore body calcite -3.8 +19.7 7 central ore body calcite -4 +22.7 8 central ore body calcite -6.4 +17.1 9 central ore body calcite +21.4 10 čukar calcite -10.8 14 11 central ore body calcite -6 +21.7 note: data numbered 1-10 from serafimovski et al. (1996), 11 from tasev (2003).note: data numbered 1-10 from serafimovski et al. (1996), 11-12 from tasev (2003). serafimovski et al.: porphyry cu mineralization related to the small tertiary volcanic intrusions in the bučim ore deposit... 111 bučim deposit indicated that ore-bearing cu-au solutions were pre do mi na ntly of the na-cl type, in which concentration of dissolved salts varies between 10 and 25 % wt eq. nacl, with density from 0.6 to 0.8 g/cm3 (according to methods given in roedder, 1984; ste rner et al., 1988; vanko et al., 1988 and bodnar, 1993). the low content of post-ore ca l cite in veinlets in the bučim deposit indicates the more basic nature of the hydrothermal solutions (ph greater than 7). the latest study of fluid inclusions was conducted on transparent polished sections made from samples of quartz veinlets and nests, from the primary mineralization. although quartz is widely distributed in the ore field, it generally forms translucent gray aggregates, and therefore suitable material for the fluid inclusion study is very rare. the majority of fluid inclusions were found in samples from the central ore body at horizon 540. about 540 different individual measurements were made on the most representative fluid inclusions (table 5). as indicated, the well-faceted quartz crystals are not typical of the bučim deposit, which complicates the use of known criteria for inclusion division into primary and seco n dary types. by the de finition of ermakov & dolgov (1979), the majority of the studied fluid inclusions were un zo ned primary inclusions. besides the dominant gas-liquid, two-phase inclusions, there are also three-phase fluid inclusions (gas + liquid + solid phase). the latter were usually larger in size (1-35 μm) and contain dark gas bu bbles and dark, transparent or opaque solids. the number of solids reached up to five (strashimirov et al., 1996). tra n s pa rent solid phases, probably kcl (strashimirov et al., 1996), generally were well faceted (figure 8a). flat hexagonal flake-like crystals of haematite (probably specularite; figure 8b), were evidenced by their shape and pinkish-red color. where present, at the highest recorded temperatures (500-550°c), specularite also dissolved. the shape of three-phase inclusions was usually isometric, rarely triangular (fig. 8c), elo ngated or having negative faceted crystal forms (fig. 8d). some two-phase inclusions contain dark gas bubbles, and the ratio between gas and liquid in them varies from 1.1 to 1.6. secondary inclusions are elongated and irregular in shape and contain smaller bubbles. homogenization temperatures measured in different types of inclusions were classified into several distinct ranges. highest temperatures (500°c-550°c) were measured in the three-phase inclusions containing more than one solid phase (table 5). several inclusions of this group did not experience homogenization at temperatures more than 580°c. homogenization temperatures of fluid inclusions with one solid phase were in the range 500-530°c. the majority of transparent solids disappear in the range from 350 to 400°c, which confirms the presence of halide crystals. high-temperature three-phase inclusions were present in the quartz, associated with haematite, magnetite and rutile in the ore sample. a small group of two-phase inclusions homogenized at temperature ranges from 490 to 460°c. they co ntain large dark bubbles (gas: liquid ratio is from 1.1 to 3.1) and sometimes homo ge nized into gas (a sign of boiling!). mineral para genesis includes quartz, pyrrhotite, pyrite and chalcopyrite. the largest group of two-phase inclusions homogenized at temperatures of 430-400°c. they apparently reflect the temperature range of massive chalcopyrite deposition from table 5. temperatures of homogenization in different types of inclusions in quartz. mineral association inclusion type no. of measured inclusions homogenization temperatures range (oc) quartz, k-feldspar three phases with 2, 3 or more solid phases 7 over 580 quartz, magnetite, haematite, rutile three phases, solid phase halite-haematite 25 500-550 quartz, magnetite, haematite, rutile three phases 58 530-550 quartz, pyrrhotite, chalcopyrite ± cubanite, valleriite two phases fluid inclu sions, large gas bubble 22 430-490 quartz, pyrite, chalcopyrite two phases 80 400-430 quartz, pyrite, chalcopyrite ± bismuthinite, enargite two phases, rela ti vely small bubble 21 320-370 quartz, pyrite two phases, probably secondary origin 17 180-200 figure 8. different types of inclusions in quartz from the bučim deposit (scale bar = 10 μm). a) three-phase fluid inclusion (liquid+gas+solid), containing a well-faceted crystal of nacl, dark gas bubble, liquid and an opaque mineral; b) three-phase fluid inclusion with haematite (hm) and a rounded nacl crystal (hl); c) three phase fluid inclusion with a triangular shape; d) three-phase primary fluid inclusion having negative crystal faces in the quartz. vol. 69/1 112 solutions. the temperature intervals 320-360°c and 200180°c correspond to the influx of the hydrothermal fluids with increased influence of terrestrial waters. 3.8. geochronological and sr-nd data the tertiary magmatism and its products in the area of interest, are described in extensive literature (karamata, 1974; janković & petković, 1974; janković, 1977; karamata & djordjević, 1980; boev et al., 1992; knežević et al., 1989; serafimovski, 1990, 1993, 1996; boev & yanev, 2001; se rafimovski et al., 2010; and lehmann et al., 2013). timing of the intrusions in the bučim deposit have been studied on several occasions. the analysis of k/ar whole rock ages of andesitic to trachyandesitic intrusions ranged between 27.5 and 24.7 ma (serafimovski, 1990; čifliganec, 1993; serafimovski et al., 2010). later studies of the magmatism age at the bučim area narrowed the age span to between 24.51 ± 0.89 and 24.04 ± 0.77 ma, as indicated by chemical-annealing (ca)-la icp-ms zircon dating (lehmann et al., 2013). recent data (table 6) reported in the works of boev et al. (1992), serafimovski (1990, 1993), serafimovski et al. (1996) and tasev (2003) based on isotopes of 87sr/86sr (0.705040-0.706980) as well as contents of rare earth elements (ree; table 8), indicated that ensuing magmas in the vicinity of bučim and its surroundings probably developed by mixing of melts from the contact between the conti nental crust and the upper mantle. the content of microand rare earth e le me nts point to a great similarity with the rock types formed in active continental margins (serafimovski, 1990; boev et al., 1992; tasev, 2003; serafimovski et al., 2010). also, the recent sr and nd isotope ratios (87sr/86sr 0.706660.70741 and 143nd/144nd 0.512487–0.512489; table 7) show that the magmatic products were slightly contaminated by continental crust material, due to partial melting of the deep parts of continental crust underthrust by collison of continetal blocks. in the late eocene-oligocene belt, magmatism between 29 and 35 ma is dominated by crustal melting with increased mantle contribution between 20 and 27 ma. 3.9. rare earth elements rare earth elements (ree) analyses have been performed on various rocks from the bučim deposit (table 8). calculated eu anomaly values ranged from 0.7409 to 0.9036 (tasev, 2003; serafimovski et al., 2010), which implies a negative eu anomaly (rollinson, 1992), and is very similar to the recent eu anomaly data which range between 0.68893-0.91251 determined by lehmann et al. (2013). distribution of the trace elements, enrichment of large ion lithophile elements (lile) and depletion in high field strength elements (hfse), indicates subduction-related magmatism. most of the magmas follow a calc-alkaline fractionation trend with shoshonitic affinities. additionally, sr/y (7 to 70) and la/yb ratios (9 to 46) show some similarities with adakite type magmas (serafimovski et al., 2010). 4. discussion interpretation of the evolution of the bučim porphyry cu deposit is based on the detailed studies of smirnov (1976), ovtchinikov (1976); janković (1981, 1990), krivtsov (1983), mitchel & garson (1984), ohmoto (1986), čifliganec (1987, 1993), sotnikov et al. (1988), serafimovski (1990, 1993) and others. a general model of the development of the bučim poprhyry cu deposit which considers ore components from their ultimate source to the place of deposition relies on the following issues: origin of the ore metals; origin of ore-bearing solutions; physical-chemical conditions for ore-bearing fluids; deposition of ore components; occu rre nces which accompany the formation of ore deposits as well as the origin of the magma. this pa per gives a brief account of all these phenomena exemplified on the bučim porphyry cu deposit. the major ore mineral is chalcopyrite accompanied by pyrite, magnetite, haematite, cuba nite, valleriite, native au, and bornite. the ore mineralization in the central part, bunardžik and vršnik ore bodies is very similar in terms of the mode of occurrence, mineral compo sition, association of elements etc. differences can only be seen in the čukar ore body. the čukar ore body is a typical example of supergene mineralization characterized by inc re ased grade of cu but low ore reserves. the major ore minerals are chalcocite and covellite, always accompanied by pyrite, tenorite, rarely native cu, malachite, azurite etc. tita nite, rutile, magnetite, haematite, chalcopyrite, pyrite, bornite, native au, molybdenite, pe tzite, calaverite, and argentite were identified as ore minerals. enargite, tetrahedrite, ga l ena, and sphalerite are less abundant. genesis of the bismuth±selenium minerals (bismuthinite, galenobismutite, krupkaite, fri edri chite, emplectite, cosalite, no. sample rock type 87sr/86sr 1 bms1 latite 0.707 2 bms2 andesite 0.707 3 bms3 andesite 0.707 4 bmk27 trachyandesite 0.705 5 bmk31 trachydacite 0.707 table 6. 87sr/86sr data for magmatic rocks from the bučim deposit. table 7. 87sr/86sr and 143nd/144nd data for magmatic rocks from the bučim deposit. sample 87sr/86sr 87sr/86sr (corrected at 24 ma) 143nd/144nd 143nd/144nd (corrected at 24 ma) ε-nd (at 24 ma) 268-1-a 0.707 0.707 0.513 0.512 -2.31 248-2 0.707 0.707 0.513 0.512 -2.31 059-1 0.707 0.707 0.513 0.512 -2.3 238-3 0.708 0.707 0.513 0.512 -2.34 serafimovski et al.: porphyry cu mineralization related to the small tertiary volcanic intrusions in the bučim ore deposit... 113 laitakarite and native bismuth) within the deposit has been related to two stages of the mineralizing process. the first one: bismuthinite, gale no bismutite, friedrichite, krupkaite, emplectite and native bismuth is related to the formation of quartzpyrite-chalcopyrite paragenesis.the second one: bismuthinite, gale no bismutite, friedrichite, krupkaite, emplectite, native bismuth and cosalite is associated with a later paragenesis of quartz, pyrite, marcasite and chalcopyrite, (but earlier than the quartz-galena-chalcopyrite stage). increased cu and fe co ncentrations in the bi-se minerals could be related to the corrosive alteration of chalcopyrite (serafimovski et al., 1990), although numerous examples of isomorphism were determined too. also, the bi±se mineralization could be prudently considered as the typomorph of endogene au mineralization in the bučim deposit. the au-pd association has been determined within the pyrite and chalcopyrite of the major ore-bearing phase in the central part orebody in the bučim deposit. increased au and palladium concentrations within pyrite are directly associated with decreased conce ntra tions of iron and sulfur as the major constituents of pyrite, which in practice means that there is substi tution of major pyrite constituents by au and pd. the au-pd concentrations in chalcopyrite are pro bably related to the mixed mineral phases that were unable to discriminate fully. beside the presence of au-pd in chalcopyrite, confirmed by serafi mo vski (1993) and serafimovski et al. (2006), in the present study there is confirmation of numerous mineral pha ses such as bi-se minerals, lai ta karite, friedrichite, cosalite, and others. gold and pd form such a mixture in the main mineral phase in pyrite and chalcopyrite equally (temperatures around 250ºc). their absence in the following phases of the ore-bearing process could indicate stabilization of the crystal lattice of pyrite and chalcopyrite in the later stage of the deposit evolution (tarkian et al., 1991; petrunov et al., 2001; eco no mou-elio po ulos, 2010). the very narrow δ34s interval (+0.2 up to +2.5‰, averaging +1.0‰), is a direct consequence of the homogeneous and quite similar physico-chemical conditions during the formation of sulfide parageneses in all of the three ore bodies in the deposit. the range of δ34s values in pyrites from all three ore bodies points to an endogeneous origin of the sulfur. a dominantly magmatic source of sulfur in porphyry deposits is consistent with the source rocks for porphyry magmas discussed below (87sr/86sr i 144nd/143nd ratios, misra, 2000, lehmann et al., 2013). owing to higher sulfur solubilities, predominantly as sh-, in more oxidized i-type hydrous magmas (burnham & ohmoto, 1980), the degree of partial melting is sufficient to extract all of the sulfur from the source rocks, and such magmas may commonly contain in excess of 0.2 wt% s (compared with perhaps an order of magnitude less sulfur in low fo2, stype magmas). in accordance with existing classifications and the results obtained for δ34s, this deposit could be classified in the first group with an interval from 0.0 up to 0.5‰ δ34s. ohmoto & rye (1979) pointed out that the deposits which belong to this group of values are closely re la ted to felsic igneous rocks (misra, 2000; fig. 9). the sulfur in the deposit is of igneous origin and was obta ined during release from the silicate melt or from sulfides in igneous rocks. nevertheless, the origin of the cu in the bučim deposit has been related to the primary magmatic intrusion. since the igneous bodies (dykes and small stocks) were too small for mobilization of the hydrothermal convective systems, the source of cu should be related to the existence of deeper and larger igneous bodies. the fact that cu could be mobilized from the serpentinites, which are lying in the basement of the area where ophiolitic comple xes were embedded, should also be taken into consideration. this scenario is of special interest if we keep in mind that the neogene calc-alkaline igneous complexes of the serbo-macedonian province are poor with respect to cu. table 8. contents of rare earth elements in intrusive and volcanic rocks of the bučim deposit (ppm). 1 2 3 4 5 6 7 8 9 10 11 12 13 14 sample mk27 mk30 mk31 mk32 059/3 bun. 059/1 bun. 268/1/a cen. p 238/3 vrš 238/4 vrš 228/1 vrš 248/2 vrš 248/1 vrš 056/3 cent. p 056/5 cent. p la 32.78 68.27 44.86 67.52 67.3 78.7 59.7 69.3 83.6 58.4 80.7 75.4 35.1 57.1 ce 59.54 119.26 86.72 118.34 124 141 113 149 170 126 155 141 81.3 125 pr 7.12 13.64 10.47 12.99 13.6 14.9 12 16.2 16.5 13.7 15.8 14.7 9.4 14.9 nd 27.07 48.2 38.8 45.95 53 54.8 45.4 59.2 60.3 50.4 59.3 54 38.7 60.5 sm 5.14 8.32 7 7.66 8.5 9.7 7.9 8.9 9.7 9.3 10.5 9.2 7.7 9.6 eu 1.45 2 1.52 1.86 1.8 2 1.8 2.1 2.3 1.9 2.2 2 1.5 1.9 gd 4.7 6.79 5.56 6.14 6.8 6.4 6 6.3 6.2 5.9 7.2 6.4 5.5 7.5 tb 0.71 0.88 0.75 0.8 0.9 0.9 0.7 0.8 0.9 0.9 1 0.9 0.8 0.9 dy 3.87 4.51 3.78 4.3 4.4 4.5 4.2 4.5 4.2 5.1 5.5 4.9 5.1 4.6 ho 0.78 0.83 0.69 0.8 0.8 0.8 0.8 0.7 0.8 0.9 0.9 0.8 0.8 1.1 er 2.25 2.33 1.91 2.34 2.2 2.6 2.3 2.2 2.3 2.8 2.6 2.4 3 2.9 tm 0.34 0.33 0.28 0.33 0.3 0.3 0.3 0.3 0.3 0.4 0.4 0.4 0.3 0.4 yb 2.26 2.3 1.89 2.31 2.6 2.3 2.2 2.3 1.8 2.5 2.9 2.7 3.7 2.7 y 23.05 24.57 20.43 24.84 25.7 243 24.2 22.9 23.6 28.4 30.2 25.6 23.4 27.7 lu 0.33 0.34 0.28 0.34 0.4 0.3 0.3 0.4 0.3 0.4 0.4 0.3 0.5 0.4 note: mk-27 trachyandesite; mk-30 trachyandesite; mk-31 trachydacite; mk-32 trachydacite ; 059-3 bun. trachyandesite; 059-1 bun. trachyandesite; 2681-a cen.p trachyandesite; 238-3 vrš. trachyandesite; 228-1 vrš. trachyandesite; 248-2 vrš. trachyandesite; 248-1 vrš. trachyte; 056-3 cent. p trachyte; 056-5 cent. p trachyandesite. data 1-4 from tasev (2003); 5-14 from lehmann et al. (2013). vol. 69/1 114 temperatures of the hydrothermal solutions during the formation of ore minerals ranged from 200-300oc to 600oc, with figures as low as 100oc for the latest ore occurrences comprising pyrite micro fillings. temperature calculations from the values of sulfur isotope composition (mineral pairs: galena-chalcopyrite) were in the range of 110 oc 160oc, which in general does not correspond with the majority of temperatures obtained during the fluidinclusion analysis (200÷580 oc, blečić, 1974; strashimirov et al., 1996). the isotopic temperatures usually do not correspond with the formation temperatures of the hydrothermal ore deposits, that was well established from fluid inclusion studies elsewhere (behr & gerler, 1987; behr et al., 1987; werner et al., 1990; hofmann & eikenberg, 1991; german et al., 1994; lippolt & werner, 1994; lüders, 1994; ritter, 1995; weber, 1997; werner et al., 2000). this indicates that ore precipitation occurred under conditions where sulfur isotope equilibrium was not established. this could be possible if we take into account that hydrothermal solutions had near-neutral ph and the total sulfur concentration was around 500–1000 ppm (strashimirov et al., 1996). an additional fact comes from the time required to establish a degree of equilibrium of 95% at 300–350oc, which is less than one year. in contrast, at temperatures of 150–200oc, which corre spond to the fo rmation temperatures of the sulfide-su lfate pairs, equilibriation needs 3000-7000 years (schwinn et al., 2006). considering the hydrodynamics of fluid migration wi thin the fault zones, it appears plausible that fluid mixing and mineral deposition processes were too rapid for equilibration of sulfur isotopes at formation temperatures. a re la ti vely fast ascent of fluids from a deep source through open fractures is consistent with the tectonic setting of the hydrothermal mineralizations in the bučim deposit (serafimovski, 1993). temperature discrepancies between sulfur isotope calculations and those obtained from fluid-inclusions studies indicate an open system, at least in the final stages, which resulted in disequilibrium sulfur fractionation. in this case we may speak about the existence of kinetic fractionation reactions. so, the s-isotopic equili bri um fractiona tions between galena and chalcopyrite at the bučim deposit gave low temperatures that might reflect cooling during the development of the paragenesis (hill et al., 2015). values of δ13c range from -3.84‰ to -10.83‰, which suggests intensive car bon fractionation and enrichment with the lighter carbon isotope. this is common for high temperature calcites (rye et al., 1974) whereas the carbon isotopic composition chan ges can be interpreted as a consequence of increase of oxidation potential of hydro ther mal solutions and oxidation of ch4 which has a light isotope signature. the variation of oxygen δ18o values in the studied calcites are within the range of +13.98‰ to +22.70‰. heavier δ18o isotope values in calcite, around +23‰, are close to equilibrim fracionation due to the participation of meteoric water. however, the value of 13.98‰ is low and reflects a lowered fracionation factor due to a high formation temperature. besides, there is significant fractionation of oxygen from the place of formation of the hy d r o thermal fluid to the place of deposition of mineralization and ore associated carbonates. it should be pointed out that such values are common in hydrothermal carbonates, since they have passed through different tectonomagmatic and geochemical settings. there were real condi tions for change of the isotopic composition especially if hydrothermal fluids have different sali nity, acidity, concentration, different water/rock ratio etc. the oxygen variation (δ18o) in samples is in the range that suggests intensive oxygen fractionation and a change of isotopic composition by way of enrichment with the lighter isotope. the results of fluid inclusions analyses suggest a large temperature range for mineral deposition. initially, hydrothermal fluids caused a change in the host rocks (replacement of quartz and k-feldspar) at temperatures of 500-600°c. fe-ti oxide mineralization was formed in the same temperature range. solutions probably were of high salinity (~30-40 or more %wt eq. nacl), as evidenced by the prevalence of three-phase inclusions, with halides, and often with more than one solid phase. as solutions cooled, the role of sulfide in the solution increased, due to disproportionation of sulfur compounds which caused the precipitation of sulphide minerals, pyrrhotite, cubanite, valleriite and small quantities of pyrite and chalcopyrite. simultaneous fluid inclusion homogenization in the same sample, into gas and liquid, indicates boiling of the hydrothermal solutions in the system. the significant role of sulfur in the solutions is confirmed by the precipitation of pyrite and chalcopyrite in a wide temperature range of fluid homogenization temperatures (430-400 and 490-400°c). the absence of three phase inclusions indicates lower salinity at that time. the latest mineral assemblages, containing bismuthinite, enargite, petzite and other minerals, were formed at temperatures of 360-320°c and below. the presene of chloride in fluid inclusions suggests the transport of ore components by chlofigure 9. δ34s values in sulfides and sulfates from the porphyry ore deposits. bučim values of sulfides are included for comparison (modi fied after ohmoto & rye (1979)). serafimovski et al.: porphyry cu mineralization related to the small tertiary volcanic intrusions in the bučim ore deposit... 115 ride complexes. circulation of hydrothermal ore-bearing solutions was conducted through the spaces of increased permeability. they are fractured, tectonized, with dense joint-fissure systems, initiated by penetration of primary intrusions (hrković, 1985). these data indicate the similarity of the formation temperature of the bučim deposit and the cu-porphyry deposits elatsite (in the panagyuriysky ore district, bulgaria) and majdanpek (in the ore district of bor, serbia) (strashimirov & kovačev, 1992). common features of these deposits are high temperatures at the beginning of mineralization and the fact that extensive three-phase inclusions in quartz are associated with fe-ti mineralizations. the formation temperature of the main cu mineralization is well above those in the medet and assarel deposits (panagurishte ore district). the reason for the higher temperatures of ore deposition could be a shorter distance from the source of ore-forming fluids. hydrothermal systems were relatively closed at the beginning of the process of mineralization, and the influence of meteoric water was also limited. preliminary isotope data of the sulfide minerals supports the assumption of the endogenous origin of hydrothermal fluids. this data relates mainly to the samples from the central part of the deposit. additional studies of the upper and marginal portions of the ore field can provide more detailed information on the development and zoning of the hydrothermal system in the bučim cu porphyry deposit. based on the age (k/ar whole rock ages from 27.5 to 24.7 ma and narrowed age span obtained by the latest data from 24.51 to 24.04 ma), strontium isotopes 87sr/86sr (0.7050400.707410) and corrected data of neodimium isotopes 143nd/144nd (0.512487-0.512489), we suggest the following scenario for the magmatic history of the bučim-damjan-borov dol ore district. a rollback of an oceanic slab located further to the sw, led to extensional and compressional features in the upper levels of the continental crust. in the middle to upper crust, three consecutive crystallization stages occurred at variable depths as indicated by amphibole zonation. the ascent of the magma through a complex assemblage of continental crust and newly formed crust with mantle affinities in variable degrees explains all the geochemical characteristics. the magma crystallized as dykes or stocks near the earth’s surface after its final emplacement and contemporaneous hydrothermal ac tivity led to different mineralization styles depending on the lithology of the host rocks. whole rock 87sr/86sr (0.706660-0.707410) and 143nd/144nd (0.512487-0.512489) isotopic compositions from the recent study are presented in figure 11. the proposed mixing curve is in agreement with the data from pe-piper & piper (2001), as well as with several isotopic analyses available for young magmatic rocks of this region (intrusive rocks from macedonia, serbia and bulgaria (yanev et al., 2008; prelević et al., 2005; marchev et al., 2004; cvetković et al., 2004 and lehmann et al., 2013). a hyperbolic mixing curve for different ratios of (sr/nd) emii/(sr/nd)dm shows mixing between a depleted mantle (dm) and an enriched mantle (emii) source. it illustrates that the measured sr-nd isotopic ratio is a result of magma mixing or crustal contamination as determined elsewhere in the region (cvetković et al., 2004; depaolo & wasserburg, 1979; marchev et al., 2004; prelević et al., 2005; rollinson, 1992; yanev et al., 2008). ree data, the high contents of large ion lithophile elements (lile), a high ba/nb ratio (116.72-190.72) and depletion in high field strength elements (hfse), appropriate to mixing of asthenospheric melts and metasomatized magma (downes et al., 1995), could easily be connected to subduction-related arc magmatism (boev et al., 1992; stolz et al., 1996). the origin of fluids from metasomatized magma is also indicated by the the ree chondrite normalized pattern (figure 12), simi lar to those of kononova et al. (1989) and boev & yanev (2001), which is close to the theoretical curve of their affinity to an aqueous fluid, reflecting the mobility of elements in this fluid (pearce et al., 1981; boev & yanev, 2001). also, we point out that most of the magmas follow a calcalkaline fractionation trend with shoshonitic affinities. accordingly, the data for europium in analyzed samples and its negative anomaly (0.68893-0.91251; figure 12), suggest that eu was removed from the melt as a compatible eu2+, figure 10. distribution of δ13cpdb vs. δ18osmow showing probable environment of origin (m-v mantle derived hydrothermal calcites). isotopic composition from some carbon reservoirs has been shown on the plot (data fields from rollinson, 1992 and ray et al., 2000). figure 11. initial 87sr/86sr vs. initial 143nd/144nd correlation diagram. vol. 69/1 116 by the processes of crystal fractionation of plagioclases (rollinson, 1992; tasev et al., 2005). most of the samples have a high sr/y and la/yb ratio, and their multi-element patterns were characterized by depletion in nb, ta and zr, and enrichment of pb and sr (table 1). the lile were enriched relative to the hfse (table 2). all these parameters, togehter with several plots zr/y vs. zr, ce/p2o5 vs. zr/ tio2 and ti vs. zr (müller et al., 1992; pearce, 1983) point to an apparent continental arc setting (boev & janev, 2001). 5. conclusions the porphyry cu mineralization within the bučim deposit is spatially and gene ti ca lly closely related to the small tertiary volcanic intrusions that have protruded through the pre ca mbrian complex of the serbo-macedonian massif within a time frame of 27.50-24.04 ma. spatially, the porphyry cu mineralization is followed by au, ocassionally platinum and pge group and bi-se minerals localized as rings around the andesite-latite necks and dykes. the major ore-bearing mineral is chalcopyrite followed by a series of sulfides and sulfosalts. ore mineralization mostly is of endogeneous origin as suggested by the stable istopes of sulfur (δ34s from +0.16 up to +2.53‰ averaging +1.06‰). the origin of ore metals and their evolution in the hydrothermal system from magma to the site of deposition has been defined by the stable isotopes of carbon (δ13c in the range from -3.84 to -10.83‰) and oxygen (δ18o within the range from +13.98 to +22.70‰), which can be interpreted as being representative of magmatic hydrothermal fluids with a pronounced contribution from meteoric water. temperatures of deposition of the major mineralizing paragenesis were defined by a fluid inclusions study, and are within the range of: 500-600°c (fe-ti oxide mineralization), 400490°c (precipitation of pyrite and chalcopyrite) and 360320°c and below (responsible for the late mineral assemblages of bismuthinite, enargite, petzite and some other minerals. fluid inclusions suggest that the transport of compo ne nts was most probably by water fluids in the form of chloride complexes and very seldom sulphate and carbonate. the evolution of the tertiary magmatism and magma origin was indicated through the 87sr/86sr isotope (0.7050400.707410) and 143nd/144nd isotope ratios (0.512487-0.512489) which confirm magma mixing or crustal contamination. this is in favour of the mixing of asthenospheric me lts and metasomatized magma, which could easily be linked to subductionrelated arc ma gmatism. references andrew, a., heinrich, c., wilkins, r. & patterson, d. (1989): sulfur isotope systematics of copper ore formation at mount isa, australia.– econ. geol., 84/6, 1614–1627. behr, h.j. & gerler, j. (1987): inclusions of sedimentary brines in postvariscan mineralizations in the federal republic of germany a study by neutron activation analysis.– chem. geol., 61, 65–77. behr, h.j., horn, e.e., frenzel-beyme, k. & reutel, c. (1987): fluid inclusion characteristics of the variscan and post-variscan mineralizing fluids in the federal republic of germany.– chem. geol., 61, 273–285. blečić, n. (1974): izveštaj o termobarohemiskim merenjima u rudnim rastvorima fluidnih inkluzija u rudnoj paragenezi bučimskog ležišta [report of thermobarochemical measurements in ore solutions fluid inclusions in bučim’s deposit ore paragenesis – in serbian].– profess. fund of bučim mine geological survey, prmb “bučim” radovis, 35 p. blevin, p. (2002): the petrographic and compositional character of variably k-enriched magmatic suites associated with ordovician porphyry cu-au mineralisation in the lachlan fold belt, australia.– min. dep., 37, 87–99. bodnar, r.j. (1993): revised equation and table for determining the freezing point depression of h2o-nacl solutions.– geoch. cosmoch. acta, 57, 683–684. boev, b., čifliganec, v., stojanov, r. & lepitkova, s. (1992): oligocensko-neogen magmatizam vo ramkite na bučimskiot blok [oligocene-neogene magmatism within the bučim blok area – in macedonian].– geol. maced., 6, 23–32. boev, b. & yanev, y. (2001): tertiary magmatism within the republic of macedonia: a review.– acta vulcan., 13/1–2, 57–71. bončev, g. (1920): petrographic and mineralogical studies in macedonia.– collection of bulgarian academy of sciences, department of natural sciences and mathematics, sofia, 13, 1–295. burnham, c.w. & ohmoto, h. (1980): late-stage processes of felsic magmatism.– mining geol. spec. iss., 8, 1–12. čifliganec, v. (1987): metalogenetske karakteristike ležišta bakra bučim u srpsko-makedonskoj metalogenetskoj provinciji [metallogenetic features of the bučim copper deposit in the serbo-macedonian metallogenetic province – in serbian].– ph.d. thesis, faculty of mining and geology, belgrade, serbia, 190 p. čifliganec, v. (1993): rudišta i pojavi na bakar vo republika makedonija: tipovi i reonizacija [copper mineralization in the republic of macedonia: types and distribution patterns in macedonian with extended summary in english].– university “sts. cyril and methodius” skopje, faculty of mining and geology štip, spec. issue, 1, 303 p. čifliganec, v. et al. (1993): studija za procenka na zlatonosniot potencijal na bučimskoto rudno pole vo pogled na istražuvanje na novi rezervi na bakar i zlato [study for gold potential estimate of the bučim ore field in regards to exploration of new copper and gold reserves – in macedonian].– professional geological survey fund, radoviš, macedonia, 95 p. čifliganec, v., serafimovski, t. & stefanova, v. (1997): content and distribution of gold-bearing minerals from the bučim porphyry copper deposit.– symposium-annual meeting-dojran, proceeding, abstract, 1, 277–278. culev, g. (1970): detalni geohemiski istražuvanja na bakar vo 1969 [detailed geochemical exploration of copper in 1969 – in macedonian].– specialist fund of the geological survey of the republic of macedonia, skopje, 78 p. cvetković, v., prelević, d., downes, h., jovanović, m., vaselli, o. & pécskay, z. (2004): origin and geodynamic significance of tertiary postcollisional basaltic magmatism in serbia (central balkan peninsula).– lithos 73, 161–186. cvijić, j. (1906): osnovi geografije i geologije makedonije i stare srbije [fundamentals for geography and geology of macedonia and ancient serbia – in serbian].– belgrade. i-iii, 1906–1911. cvijić, j. (1924): geomofologija [geomorphology – in serbian].– belgrade i-ii, 1924–1926. figure 12. chondrite normalized ree patterns (c1 chondrite values after sun & mcdonough, 1989). serafimovski et al.: porphyry cu mineralization related to the small tertiary volcanic intrusions in the bučim ore deposit... 117 denkovski, gj., ivanov, t. & dumurdzanov, n. (1983): izveštaj za kompleksnite geološki istražuvanja na rudnata oblast bučim-damjanborov dol vo 1982 [report for the complex geological exploration of the bučim-damjan-borov dol ore area in 1982 – in macedonian].– professional fund of the geological survey of the republic of macedonia, skopje, 87 p. denkovski, n. & bandilov, l. (1985): izveštaj za kompleksnoto geološko istražuvanje na oblasta bučim-damjan-borov dol, lokalnost čukarka [report for the complex geological exploration of the bučimdamjan-borov dol ore area, čukarka locality – in macedonian].– professional fund of the geoinstitute, republic of macedonia, skopje, 62 p. depaolo, d.j. & wasserburg, g.j. (1979): petrogenetic mixing models and nd–sr isotopic patterns.– geoch. cosmoch. acta, 43, 615–627. downes, h., seghedi, i., szakacs, a., dobosi, g., james, d.e., vaselli, o., rigby, i.j., ingram, g. a., rex & pécskay, z. (1995): petrology and geochemistry of late tertiary/quaternary mafic alkaline volcanism in romania.– lithos, 35, 65–81. dumurdžanov, n., rakičević, t. & petkovski, p. (1969): tolkuvač za osnovnata geološka karta (bgm) na sfr yugoslavija list štip [guide for the basic geological map (bgm) of s.f.r. yougoslavia sheet štip – in macedonian].– geological survey of the republic macedonia, skopje, 61 p. dumurdzanov, n., serafimovski, t. & burchfiel, b.c. (2004): evolution of the neogene-pleistocene basins of macedonia: geol. soc. america digital map and chart series mc01, 20 p. economou-eliopoulos, m. (2010): platinum-group elements (pge) in various geotectonic settings: opportunities and risks.– hell. j. geosc., 45, 65–82. ermakov, n.p & dolgov, y.a. (1979): termobarogeokhimiya [thermobarogeochemistry – in russian].– nedra, moscow, russia, 270 p. german, a., lang, r., werner, w. & friedrich, g. (1994): zur mineralogie und geo chemie der erzgänge im bergbaurevier freiamtsexau, mittlerer schwarzwald.– in: storch, d.h. & werner, w. (eds.): die erzund mineralgänge im alten bergbaurevier ‘‘freiamtsexau, mittlerer schwarzwald abh. geol. landesamt baden-württemberg, 14, 119–155. grinenko, a. v. & grinenko, n.l. (1974): geokhimiya izotopov sery [geochemistry of sulfur isotopes – in russian].– publisher “nauka”, moscow, russia, 274 p. günther, d., von quadt, a., wirz, r., cousin, h. & dietrich, v.j. (2001): elemental analyses using laser ablation–inductively coupled plasma-mass spectrometry (la-icp-ms) of geological samples fused with li2b4o7 and calibrated without matrix-matched standards.– microchim. acta, 136, 101–107. halter, w.e., bain, n., becker, k., heinrich, c.a., landtwing, m., von quadt, a., clark, a.h., sasso, a.m., bissig, t. & tosdal, r.m. (2004): from andesitic volcanism to the formation of a porphyry cu–au mineralizing magma chamber: the farallon negro volcanic complex, northwestern argentina.– j. volc. and geoth. res., 136, 1–30. harkovska, a., yanev, y. & marchev, p. (1989): general features of the paleogene orogenic magmatism in bulgaria.– geol. balc., 19, 37–72. heinrich, c.a. & neubauer, f. (2002): cu–au–pb–zn–ag metallogeny of the alpine-balkan-carpathian-dinaride geodynamic province.– min. dep., 37, 533–540. hill, n.j., jenkin, g.r.t., boyce, a.j., sangster, c.j.s., catterall, d.j., holwell, d.a., naden, j. & rice, c.m. (2015): how the neoproterozoic s-isotope record illuminates the genesis of vein gold systems: an example from the dalradian supergroup in scotland.– in: jenkin, g.r.t., lusty, p.a.j., mcdonald, i., smith, m.p., boyce, a.j. & wilkinson, j.j. (eds.): ore deposits in an evolving earth. the geological society of london, special publication, 393, 213–248. hofmann, b. & eikenberg, j. (1991): the krunkelbach uranium deposit, schwarzwald, germany. correlation of radiometric ages, u–pb, u–xe–kr, k–ar, th–u with mineralogical stages and fluid inclusions.– econ. geol., 86, 1031–1049. hristov, s., karajovanovik, m. & stračkov, m. (1973): list kavadarci, osnovna geološka karta 1:100 000 [sheet kavadarci, basic geological map 1:100000 – in macedonian].– federal geological survey, belgrade. hrković, k. (1985): strukturno-petrofizička-metelagonetska proučavanja rudnog polja bučim [structural-petrophysical-metallogenetic studies of the bučim ore field – in serbian].– faculty of mining and geology, belgrade, serbia, 46 p. ivanov, t. & jašmakovski, b. (1970): odredba i interpretacija na rudni primeroci od naođališteto bučim centralen del i čukar [determination and interpretation of ore polished sections from the bučim ore deposit central part and čukar – in macedonian].– professional fund of geological survey skopje, 29 p. ivanov, t. (1982): metalogenetski proučuvanja na oblasta bučim-damjanborov dol [meta llo ge ne tic study of the bučim-damjan-borov dol ore area – in macedonian].– bučim mine pro fessional geological survey fund, radoviš, macedonia, 76 p. janković, s. & petković, m. (1974): metallogeny and concepts of geotectonic development of the yugoslavia.– in: proceeding: metallogeny and concepts of geotectonic development of the yugoslavia, dedicated to prof. dr. d. milovanović, faculty of mining and geology, belgrade, serbia, 369–394. janković, s. (1977): the copper deposits and geotectonic setting of the tethyan eurasian metallogenetic belt.– min. dep., 12/1, 37–47. janković, s. (1981): mineralna ležišta – geneza rudnih ležišta [mineral ore deposits-genesis of ore deposits – in serbian].– faculty of mining and geology, belgrade, serbia, 529 p. janković, s., (1990): ore deposit of serbia.– faculty of mining and geology, belgrade, 765 p. janković, s. (1997): the carpatho-balkanides and adjacent area: a sector of the tethyan eurasian metallogenic belt.– min. dep., 32, 426–433. janković, s., serafimovski, t., jelenković, r. & čifliganec, v. (1997): metallogeny of the vardar zone and serbo-macedonian mass.– symposium-annual meeting, proceeding, dojran, 29–67. jensen, m. l. (1959): sulfur isotopes and hydrothermal mineral deposits.– econ. geol., 54/3. karamata, s. (1974): geohemijske, petrološke i metalogenetske provincije kredno-tercijarne starosti u delovima balkanskog poluostrva i male azije [geochemical, petrological and metallogenetic provinces of cretaceous-tertiary age at parts of the balkan peninsula and middle east – in serbian].– sanu, special edition, vol. cdlxxv, belgrade, serbia, 55 p. karamata, s. & lovrić, a. (1978): the age of metamorphic rocks of brezovica and its importance for the explanation of ophiolite emplacement.– bull. acad, serbe, sci., 17, 1–9. karamata, s. & djordjević, p. (1980): origin of the upper cretaceous and tertiary magmas in the eastern parts of the yugoslavia.– bull. acad. serb. des sci., et des arts. lxxii classe des sci. et mathem., belgrade, 20, 99–108. karamata, s. (1983): koncentracija nekih mikroelemenata u tercijarnim magmatitima istočnih delova jugoslavije povezanih sa njihovom geotektonskom pozicijom [concentration of some microelements in tertiary magmatites of eastern part of yugoslavia related to their geotectonic position – in serbian].– glas cccxxxv sanubelgrade. department of natural and matemathical sciences, 49, 39–54. knežević, v., steinger, r.h., djordjević, p. & karamata, s. (1989): precambrian contribution to the tertiary granitic melts at the southern margin of the panonian basin. symposium precambrian granitoides.– abstracts. geol. survey of finland espoo, helsinki, spec., 8, 75 p. kononova, v.a., terzic, m. & sveshnikova, e.b. (1989): petrochemical series of alkali basalts in the vardar zone and carpatho-balkan arc.– macedonian academy of sciences and arts, 29–44. krivtsov, a.l. (1983): geologicheskiye osnovy prognoza i razvedki medno – porfirovykh mestorozhdeniy [gegological fundamentals of prognosis and exploration of copper porphyry deposits – in russian].– publisher “nedra”, moscow, russia, 254 p. lehmann, st., barcikowski, j., von quadt, a., gallhofer, d., peytcheva, i., heinrich, c.a. & serafimovski, t. (2013): geochronology, geochemistry and isotope tracing of the oligocene magmatism of the bučim-damjan-borov dol ore district: implications for timing, duration and source of the magmatism.– lithos, 180/181, 216–233. lippolt, h.j. & werner, o. (1994): die genetische aussage von bleiisotopen-verhältnissen in bleiglanzen des bergbaureviers freiamt-sexau, mittlerer schwarzwald.– in: storch, d.h. & werner, w. (eds.): die erz-und mineralgänge im alten bergbaurevier ‘‘freiamt-sexau, mittlerer schwarzwald abh. geol. landesamt baden-württemberg, 14, 191–205. lüders, v. (1994): geochemische untersuchungen an gangartmineralen aus dem bergbaurevier freiamt-sexau und dem badenweiler-quarzriff, schwarzwald.– in: storch, d.h. & werner, w. (eds.): die erz-und mineralgänge im alten bergbaurevier ‘‘freiamt-sexau, mittlerer schwarzwald abh. geol. landesamt baden-württemberg, 14, 173–191. majer, v. (1958): trahi-andezit (delenit latit) iz pilava i šopura u makedoniji [trachy-andesite (delenite latite) from pilav and sopur in macedonia – in croatian].– yearbook of the faculty of philosophy, skopje, 2/7, 23–32. marchev, p., raicheva, r., downes, h., vaselli, o., chiaradia, m. & moritz, r. (2004): compositional diversity of eocene–oligocene basaltic magmatismin the eastern rhodopes, se bulgaria: implications for genesis and tectonic setting.– tectonophysics, 393, 301–328. misra, k. (2000): understanding mineral deposits.– kluwer academic publishers, dodrecht, netherland, 845 p. mitchell, a.h.g. & garson, m.s. (1981): mineral deposits and global tectonic settings.– academic press, new york, 410 p. mudrinić, c. & petković, m. (1974): izotopni sastav sulfura u piritima iz rudnog polja bučim [sulfur isotope composition of pyrites from bučim vol. 69/1 118 ore field – in serbian].– faculty of mining and geology, belgrade, serbia, 22–31. müller, d., rock, n.m.s. & groves, d.i. (1992): geochemical discrimination between shoshonitic and potassic volcanic-rocks in different tectonic settings-a pilot-study.– min. petrol., 46, 259–289. müller, d. & groves, d.i. (2000): potassic igneous rocks and associated gold-copper mineralization.– springer-verlag berlin-heidelberg, 272 p. nevenić, n. (1984): izveštaj o rudno-mikroskopskim ispitivanjima primeraka iz bunardžika, bučim [report from ore-microscopic study of samples from bunardžik, bučim – in serbian].– professional fund geoinstitute belgrade, 14 p. ohmoto, h. & rye, r.o. (1979): isotopes of sulphur and carbon.– in: barnes, h.l. (ed.): geochemistry of hydrothermal ore deposits, 2nd ed. john wiley & sons, new york, 509–567. ohmoto, h. (1986): stable isotope geochemistry of ore deposits.– in: valley, j.w., taylor, h., p ir, o. & neit, j.r. (eds.): stable isotopes in high temperature geological processes. rev. mineral, 16, 491–559. ovtchinikov, l. (1976): istochniki rudnogo veshchestva endogennykh mestorozhdeniy i nadezhnost’ kriteriyev ikh ustanovleniya [ore sources of endogenous deposits and reliability criteria of their establishment – in russian].– proceedings of sources of ore deposits, publ. nauka, moscow, 100–120. palinkaš, l. strmić palinkaš, s., bermanec, v., serafimovski, t. & vincetić, i. (2008): fluid inclusion in quartz from the bučim cu-porphyry deposit, eastern macedonia.– in: serafimovski, t. (ed.): proceedings of the national congres of macedonian geologists. geologica macedonia, spec. no. 2, 193–199. pamić, j. & jurković, i. (1997): alpine magmatic-metallogenic formations of the northwestern and central dinarides.– rud.-geol-naft. zb. zagreb, 9, 1–9. pavičević, m. & rakić, s. (1983): proučavanje pojava zlata, srebra i drugih retkih elemenata u rudama centralnog rudnog tela, bučim [study of occurence of gold, silver and other rare elements in ores from the central ore body, bučim – in serbian].– ulema, belgrade, 202 p. pavlović, m. (1939): izveštaj o detaljnim geološkim istraživanjima lista štip [report for detailed geological exploration of the sheet štip 1:100000 – in serbian].– annuals of geological institute, kingdom jugoslavia, belgrade, 6, 43 p. pearce, j.a. (1983): role of the sub-continental lithosphere in magma gene sis at active continental margins.– in: hawkeswoth, c.j. & norry, m.j. (eds): continetal basalts and mantle xenoliths. shiva, nantwich, 230–249. pearce, t.a., alabaster, t., shelton, a.w. & searle, m.p. (1981): the oman ophi o lite as a cretaceous arc-basin complex: evidence and implications.– phil. trans. of r. soc., london a-300, 299–317. pe-piper, g. & piper, d.j.w. (2001): late cenozoic, post collisional aegean igneous rocks: nd, pb and sr isotopic constraints on petrogenetic and tectonic models.– geol. mag., 138, 653–668. petković, m. (1966): geohemijska prospekcija rudne oblasti damjanbučim [geochemical prospection in the damjan-bučim ore area – in serbian].– str. faculty of mining and geology, belgrade, serbia, 34 p. petković, m., et al. (1968): geohemiska prospekcija rudne oblasti damjan-bučim i susednih oblasti [geochemical prospection in the damjan-bučim ore area and its neighbo u ring area – in serbian].– str. faculty of mining and geology, belgrade, serbia, 45 p. petrunov, r., dragov, p, ignatov, g., heykov, h., iliev, ts., va s s i leva, n., tzatzov, v., djunakov, s. & doncheva, k. (1992): hy drothermal pge-mine ra li zation in the elatsite porphyry-copper de po sit (sredna gora metallogenic zone, bulgaria).– co mpt. ren. acad. bulg. sci, 45/4, 37–40. petrunov, r., serafimovski, t. & dragov, p. (2001): new finding of pge-mineralisation in porphyry-copper environment-the bučim deposit, macedonia: preliminary microscope and microprobe data.– abcdgeode 2001 workshop vata bai, romania, 79, suppl. 2, 79–80. petunikov, g. (1940): berging uber eine interesuchungen auf kopferze in macedonien.– montanistischen rundschau sonderabduck, 17. petunikov, g. (1944): kupfererzvorkommen bei dorfe butschim kreis štip in macedonien sonderabdisk aus “mettal und erz”, wien, 42 jahr h 9/10. prelević, d., foley, s.f., romer, r.l., cvetković, v. & downes, h. (2005): tertiary ultrapotassic volcanism in serbia: constraints on petrogenesis and mantle source characteristics.– j. petrol., 46, 1443– 1487. ray, j.s., ramesha, r., pandea, k., trivedi, j.r., shukla, pn. & patel, p.p. (2000): isotope and rare earth element chemistry of carbonatite ± alkaline complexes of deccan volcanic province: implications to magmatic and alteration processes.– j. asian earth sci., 18, 177–194. ritter, j. (1995): genese der mineralistation herrmanngang im albtalgranit, se-schwarzwald und wechselwirkungen mit dem nebengestein.– karls. geoch. hefte, 8, 1–132. roedder, e. (1984): fluid inclusions.– reviews in mineralogy, geological society of united states of america, 12, 644 p. rollinson, h. (1992): using geochemistry data: evaluation, presentation, interpretation.– prentice hall, an imprint of pearson education, harlow, england, 352 p. rye, r., hall, w. & ohmoto, h. (1974): carbon, hydrogen, oxygen and sulphur isotope study of the lead-silver-zinc deposit, southern california.– econ. geol., 69, 468–481. sakai, h. (1968): isotopic properties of sulfur compound in hydrothermal processes.– geoh. j., 2, 29–49. schefer, s., cvetkovic, fügenschuh, b., kounov, a., ovtcharova, m., schaltegger, u. & schmid, s.m. (2011): cenozoic granitoids in the dinarides of southern serbia: age of intrusion, isotope geochemistry, exhumation history and significance for the geodynamic evolution of the balkan peninsula.– int. j. earth sci., 100, 1181–1206. schmid, s.m., bernoulli, d., fügenschuh, b., kounov, a., oberhänsli, r., sche fer, s., van hinsbe rgen, d. & ustaszewski, k. (2013): similarities and differences between alps carpathians. dina ri des–hellenides and anatolides–taurides.– egu, 15, 3525. schwinn, g., wagner, t., baatartsogt, b. & markl, g. (2006): quantification of mixing processes in ore-forming hydrothermal systems by combination of stable isotope and fluid inclusion analyses.– geoch. cosm. acta, 70, 965–982. serafimovski, t. (1990): metalogenija na zonata lece-halkidiki [metallogeny of the lece-chalkidiki zone – in macedonian].– ph.d. thesis, faculty of mining and geology, stip, 390 p. serafimovski, t., mankov, s. & čifliganec, v. (1990): bizmuthselenium mineralization wi thin copper deposit bučim-radovis.– 12th congress of geologists of yugoslavia, ohrid, 3, 73–85. serafimovski, t., čifliganec, v. & mankov, s. (1992): morfologija na zlatoto prisutno vo porfirskoto naođalište na bakar bučim istočna makedonija [morphology of gold present in the bučim porphyry copper deposit eastern macedonia – in macedonian].– 24th october counceling of miners and metalurgists, bor, serbia, 52–55. serafimovski, t. (1993): structural metallogenetic characteristics of the lece-chakidiki zone: types of mineral deposits and di stribution.– special edition of rgf stip, 2, 328 p. serafimovski, t. & boev, b. (1996): metallogeny of the kratovo-zletovo volcano-intrusive co m plex.– terranes of serbia (356), 347–352. serafimovski, t., čifliganec, v., janković, s. & boev, b. (1996): genetic model of the bučim porphyry copper deposit, r. macedonia.– in: proceedings of the annual meeting, unesco-igcp project 356, sofia, 1, 63–75. serafimovski, t., jelenković, r. & alexandrov, m. (2000): geodynamics and evolution of the alpine ore deposits in southern parts of the carpatho-balkanides.– abstract book, abcd-geode 2000 workshop, borovets, bulgaria, 31. serafimovski, t. & tasev, g. (2005): sulfur isotope composition of some polymetallic deposits in the republic of macedonia.– geol. maced., 19/1, 1–11. serafimovski, t., tasev, g. & lazarov, p. (2006): au-ag-te-bi-se minerals associated with porphyry copper mineralization in the bučim copper mine, r. macedonia.– au-ag-te-se deposits igcp-486, field workshop, izmir, turkey, 154–158. serafimovski, t., stefanova, v. & volkov, a.v. (2010): dwarf copper–gold porphyry deposits of the bučim–damjan–borov dol ore district, republic of macedonia (fyrom).– geol. ore dep., 52, 179–195. serafimovski, t., blažev, k., tasev, g. & pockov, k. (2013): aupd bearing pyrites and chalcopyrites from the bučim porphyry copper deposit, eastern macedonia.– proceedings of the 12th biennial sga meeting, uppsala, sweden, 2, 876–879. shelton, k.l. & rye, d.m. (1982): sulfur isotope compositions of ore from mines gaspe, quebec: an example of sulfate-sulfide isotopic disequilibria in ore-forming fluids with applications to other porphyry-type deposits.– econ. geol. 77, 1688–1709. smirnov, v.l. (1976): evolyutsiya istochnikov endogennykh rudnykh mestorozhdeniy v techeniye istorii zemli [evolution of sources of endogoneous ore deposits during the history of earth – in russian].– proceedings of sources of ore deposits, publ. “nedra”, moscow, 8–11. sotnikov, v.i., berzina, a.p. & jamsran, m. (1985): med’ rudnyye formatsii v mongol’skoy narodnoy respublike [copper ore formations of mongolian people’s republic – in russian].– nauka, novosibirsk, 225 p. sterner, s.m., hall, d.l. & bodnar, r.j. (1988): synthetic fluid inclusions. v. solubility relations in the system nacl-kcl-h2o under vapor saturated conditions.– geoch. cosm. acta, 52, 989–1005. stojanov, r. & serafimovski, t. (1990): osnovni karakteristiki na tercierniot magmatizam vo oblasta bučim-borov dol [basic features of the tertiary magmatism in the bučim-borov dol area – in macedonian].– 12th congress of geologists of yugoslavia, ohrid, 2, 404–423. serafimovski et al.: porphyry cu mineralization related to the small tertiary volcanic intrusions in the bučim ore deposit... 119 stojanov, r. & boev, b. (1993): oligocensko-neogeniot magmatizam vo oblasta na bu či ms kiot blok [oliocene-neogene magmatism at the bučim blok area – in macedonian].– in: study for potentiality of the bučim ore field in regards to discovery of new copper and gold reserves. pro fessio nal fund of the bučim mine geological survey, prmb buchim-radoviš, 93 p. stolz, a.j., jochum, k.p, spettel, b. & hofmann, a.w. (1996): fluidand melt-related enrichment in the subarc mantle: evidence from nb/ta variations in island arc basalts.– geology, 24/7, 587–590. strashimirov, s. & kovatchev, v. (1992): temperatura na formirane na medni nakhodishta ot zona danni ot prouchvaniya srednogorie fluidni vklyuchvane v minerali [temperature of formation in copper deposits from the srednogorie zone–data from fluid inclusion studies in minerals – in bulgarian with english abstract].– rev. bulg. geol. soc., 53/2, 1–12. strashimirov, str., serafimovski, t. & kovachev, v. (1996): temperatures of the ore-forming processes in the bučim porphyry copper deposit (macedonia): data from fluid inclusion studies.– geol. ore dep., moscow, 38/4, 373–377. sun, s.s. & mcdonough, w.f., (1989): chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes.– geol. soc., london, special publications 42, 313–345. taylor, h.p. (1987): comparison of hydrothermal systems in layered gabbros and granites, and the origin of low-δ18o magmas.– in: magmatic processes: physicochemical principles. geoch. soc. special publication 1, 337–357. taylor, h.p. (1997): oxygen and hydrogen isotope relationships in hydrothermal mineral deposits.– in: barnes, h.l. (ed.): geochemistry of hydrothermal ore deposits, 3rd ed. new york, wiley-interscience, 229–302. tarkian, m., eliopoulos, d.g. & economou-eliopoulos, m. (1991): mineralogy of precious metals in the skouries porphyry copper deposit, n. greece.– neu. jahr. min. abh., 12, 529–537. tasev, g. (2003): polimetalnite mineralizacii povrzani so tercierniot magmatizam vo republika makedonija [the polymetallic mineralizations related with tertiary magmatism in the republic of macedonia – in macedonian].– masters thesis, faculty of mining and geology, university “sts. cyril and methodius”, štip, 176 p. tasev, g., serafimovski, t. & lazarov, p. (2005): new k-ar, 87sr/86sr, ree, and xrf data for tertiary volcanic rocks in the sasatoranica ore district, macedonia.– in: jingwen mao & frank p. bierlein (eds.): mineral deposit research: meeting the global challenge, 8th sga biennial meeting, beijing, china, 837–840. tomson, i.n., serafimovski, t. & kochneva, n.t. (1998): cenozoic metallogeny of eastern macedonia.– geol. ore dep., 40/4, 195–204. vanko, d.a., bodnar, r.j. & sterner, s.m. (1988): synthetic fluid inclusions. viii. vapor-saturated ha lite solubility in part of the system nacl-cacl2-h2o, with application to fluid inclu si ons from oceanic hydrothermal systems.– geoch. cosm. acta, 52, 2451–2456. volkov, a., serafimovski, t., kochneva, n.t., tomson, i.n. & tasev, g. (2006): the alshar epithermal au-as-sb-tl deposit, southern macedonia.– geol. ore dep., 48/3, 175–192. volkov, a., serafimovski, t. & stefanova, v. (2010): formation mechanism of dwarfish cu-au porphyry deposits of macedonia.– dokl. earth sci., 431/5, 649–655. weber, a. (1997): geochemische untersuchungen zur genese der bleizink-lagerstätte am scha u i n s l a nd im schwarzwald [geochemical studies on the genesis of lead-zinc deposit at the schauinsland in the black forest – in german].–unpublished diploma thesis, university of tübingen, 82 p. werner, w., schlaegel-blaut, p. & rieken, r. (1990): verbreitung und ausbildung von wolframmineralisationen im kristallin des schwarzwaldes [dissemination and training of tungsten mineralization in the crystalline of the black forest – in german].– jh. geol. landesamt baden-württemberg, 32, 17–61. werner, w., franzke, h.–j. & lüders, v. (2000): zur genese der zink-blei-lagerstätte schauinsland [on the genesis of the zinc-lead deposit schauinsland – in german].– erzmetall, 53, 273–285. yanev, y., boev, b., doglioni, c., innocenti, f., manetti, p, pecskay, z., tonarini, s. & d’orazio, m. (2008): late miocene to pleistocene potassic volcanism in the republic of macedonia.– min. petr., 94, 45–60. zarić, p. (1974): studija genetsko-paragenetskih karakteristika cu mineralizacije u bučimu sa pregledom mineralizacionim fazama tog ciklusa [study of genetic-paragenetic features of cu-mineralization bučim with a review of mineralization stages of that cycle – in serbian].– professional fund, bučim mine, 63 p. geologia croaticageologia croatica geologia croatica 66/3 205–218 6 figs. 1 tab. zagreb 2013 the geology of the camerano area through the reconstruction of sedimentary sequences of the urban caves  roberto bizzarri1, angela baldanza1, irene luccioni2 and alberto recanatini2 1 department of earth science, university of perugia, p.za università 1 i-06123 perugia, italy; (roberto.bizzarri@libero.it, angela.baldanza@unipg.it) 2 via c. colombo 18 i-60021, camerano (an), italy; bvzm2002@yahoo.it doi: 10.4154/gc.2013.16 1. introduction around the mt. conero promontory of the marches region (central italy, fig. 1), several hill towns, including sirolo, loreto, castelfidardo, osimo and camerano, have manmade cave systems, originally intended for various uses e.g., water supply, housing, defence, granaries, escape routes, gatherings and rituals (recanatini, 1997, 2000). the extensive camerano “underground town” is composed of more than twenty complexes, formerly all connected. a local popular saying attests that “...there is more of camerano underground than above ground”. the entire cave system is localized under the historical centre, in the area of the first piceno settlement of vii-vi century b.c. (as testified by the necropolis at the western side of the hill), subsequently occupied by the nucleus of the medieval fortress (castelvecchio, 800 a.d.). starting in pre-roman times, the caverns were excavated in weakly cemented marine sands and clays. the original purpose of such wide and pervasive excavation is still unknown. the interpretation of sandstone quarries seems ab stra ct the historical town of camerano (ancona, central italy), built on a hill just west of the mt. conero promontory, is laced with a broad underground system of remarkable man-made caves. thanks to the caves, we can view and describe a composite sedimentological and stratigraphic section of early pleistocene (calabrian) marine deposits, which lack subaerial outcrops. this study is aimed at a better definition of the sedimentological and palaeoenvironmental context of the camerano area, and at improving the knowledge of the camerano caves. sediments are mainly couplets of massivetolaminated, yellow-brown, bioclastic calcareous sand and massive, grey-green clay, of variable thickness. each couplet shows an erosive basal surface and normal gradation, from sand to clay. plane-parallel lamination, marked by recurring variations in grain size, is attributed to traction carpets and the sand horizons to resedimentation by sediment-gravity flows, with an eastern source (mt. conero). conversely, clay reflects both western distal river-delta supply and a local contribution from marine productivity. beds of matrix-supported gravel made of heterometric clay fragments dispersed in a bioclastic sand matrix also occur within the sedimentary section. these interpretations differ partially from earlier geological schemes and offer new insights into the palaeoenvironmental reconstruction of the camerano area. the reconstruction involves a tectonically active early pleistocene basin, mainly dominated by clay sedimentation, but periodically reached by stormand seismic-induced carbonate gravity flows. the matrix-supported conglomerate of large clay fragments was probably derived from remobilization of partially lithified deposits along the basin’s eastern flank. keywords: sedimentology, periadriatic basin, early pleistocene, marches, central italy geologia croatica 66/3geologia croatica 206 unsatisfactory, due to the richness of architectural motifs and ornaments testifying to a continuous human use through the centuries. furthermore, the underground town has been utilized from the xi century a.d. to recent years for several different uses, often denoting a parallel evolution with the growth of the external town (recanatini, 1990, 1997). thanks to the interest and competence of the camerano municipality and to the contribution of local amateurs, the historical and artistic features of the cave system have been well studied and the underground town is now largely accessible. nevertheless, its geological features are still largely unknown. the recent building development superimposed on the medieval remains has totally obliterated the geological features and the outcrops all around the hill. thus the exceptional underground town is the only avenue to reconstructing a composite sedimentological and stratigraphic section of the early pleistocene marine deposits (luccioni, 2007), a component of the composite evolution of the periadriatic basin (a sector of the plio-pleistocene adriatic foredeep sen su lato). in the whole marches area (fig. 1a), the surface structural configuration of the foredeep sediments, essential ly referable to as a gentle, easterly dipping growth monocline, largely obscures the complexity of the basin’s evolution. a series of buried deep-seated active thrusts and trans verse faults, strongly affected the basin physiography and guided the clastic fill patterns, imposing major control during much of the plio–pleistocene and dividing the basin into sectors with unique features and evolution (ori & friend, 1984; bigi et al., 1997; centamore & nisio, 2003; cantalamessa & di cel ma, 2004). the basin is mainly filled by a plio-pleistocene clay-rich succession, and a general regressive trend is usually recognized, but the occurrence of several coarse clastic bodies, commonly underlain by major unconformities and intercalated at various stratigraphic levels, testifies to a complex sedimentary evolution (cantalamessa et al., 2002; cantalamessa & di celma, 2004). recent studies indicated the occurrence of submarine canyons in the southwestern area, further complicating the sedimentological and palaeoenvironmental scenery (di cel ma et al., 2010; di celma, 2011; di celma & can talamessa, 2012). this work provides description and interpretation of sedimentary features never previously described in the ancona sector. in spite of their position in the uppermost part of the pliopleistocene sedimentary sequen ce, within the general shallowing-upward trend, the studied deposits record outer-shelf resedimentation rather than beach and subaerial environments. the composite underground sec tion of camerano puts a new light on sedimentary environments and processes and gives some insight into the evolution of the eastern margin of the basin, at least to the west of the conero mountain ‘island.’ 2. geological setting camerano is located 15 km sw of ancona, in a hilly territory on the western flank of mt. conero, and was built on top of a hill at about 231 m above s.l. (fig. 1). mt. conero figure 1: a) geological sketch of the ancona sector. the marches area is also underlined (light gray in the insert). b) comparison between lithostratigraphic schemes proposed for the pliocene-pleistocene of the periadriatic basin. mnn=mediterranean neogene nannofossil (according to rio et al., 1990). bizzarri et al.: the geology of the camerano area through the reconstruction of sedimentary sequences of the urban caves geologia croatica 207 is an anticline of umbria-marches meso-cenozoic litho strati graphic units. the hilly area west of mt. conero is cut by the present-day aspio and musone river valleys, both part of the wider chienti basin. it belongs geologically to the neo gene-quaternary periadriatic basin that developed during the late phases of the apennine orogeny as the foredeep and foreland migrated eastward (boccaletti et al., 1986, 1991; ricci lucchi, 1986; calamita et al., 1991; cen t amore et al., 1991; ori et al., 1991; centamore & nisio, 2003). the main structure of the periadritic basin is the result of at least three different tectonic phases, that took place from the miocene to recent times (calamita et al., 1991; ori et al., 1991; cello et al., 2009). on the basis of different tectono-sedimentary evolution, the periadriatic basin can be divided in the ancona, fermo, teramo, and chieti sectors (cantalamessa et al., 1986; centamore & nisio, 2003; centamore et al., 2009). several authors interpret ed the ancona sector (fig. 1a), (which includes the camerano territory), as a pleistocene syn-tectonic basin (wedgetop basin: centamore et al., 1991; open piggy-back ba sin sensu ori et al., 1991), related to evolution of the marches foredeep basin. the ancona sector is bordered to the north and south by ne-sw oriented structural highs (faulted uplifts), while to the east and west it is bounded by compressio nal structures (anticlines, which are partially buried: cen tamore et al., 2009). the entire periadriatic basin was submarine during most of the pliocene and pleistocene. the sedimentary deposits record the composite effects of tectonics and sea-level changes. several transgressive-regressive sedimentation cycles, delimited by major unconformities, are recognizable (fig. 1b: colalongo et al., 1979; cantalamessa et al., 1986; nanni et al., 1986; centamore et al., 1991, 2009; ori et al., 1991; cantalamessa & di celma, 2004; cello et al., 2009; micarelli et al., in press). vertical and lateral facies variations suggest an intra-basin palaeoenvironmental differentiation, induced by local tectonics and sea-level fluctuations (cantalamessa & di celma, 2004; cello et al., 2009; di celma et al., 2010; di cel ma, 2011; di celma & cantalamessa, 2012). the pliocene pleistocene marine succession (fig. 1b) shows an overall transgressive-regressive trend, characterized, from base to top, by neritictolittoral sandstone and conglomerate deposits (pliocene cycle), by pelitic deposits with interlayered gravely sand/sandstone and sandy clay horizons (mu tignano formation), and finally by neritictolittoral and/or continental sand and gravel (fermo formation) (cf. cantalamessa et al., 1986; centamore & mica­ relli, 1991; centamore et al., 1991, 2009; centa­ more & nisio, 2003). recent geological mapping led to a partial stratigraphic revision (cello et al., 2009; sarti et al., in press): deposits from both the pliocene cycle and the mutignano formation are now grouped in the “argille azzurre” formation (faa formazione delle argille azzurre: early pliocene early pleistocene: fig. 1b). the faa is mainly pelitic and is subdivided into a pliocene marly pelite with minor sandstones and a pleistocene dominantly pelitic portion, characterized by four intercalated lithofacies: gravely sand/sandstone, sand/sandstone, clayey sand and san dy clay. based on the sand/clay ratio and the distribution of lithofacies, several local members are also recognizable in the faa (cantalamessa et al., 2002; cantalames sa & di celma, 2004; cello et al., 2009). this study deals only with the pleistocene section. the camerano sedimentary sequence is characterized by a lower part of mainly pelitic composition and by an upper part dominated by sand/sandstone intermingled with clay, formerly referred to as the marne di numana and sabbie di monte gallo formations, respectively, and as the mutignano formation (fig. 1b: fancelli & radrizzani, 1964; cen­ tamore et al., 1991; centamore & micarelli, 1991; cantalamessa & di celma, 2004). on the new geological maps (sarti et al., in press), the camerano sedfigure 2: map of the camerano underground system (modified after recanatini, 1990): a) planar view; b) section view (same horizontal and vertical scale). 1=grotta ricotti; 2=grotta corraducci; 3=grotta gasparri-trionfi; 4=grotte del torrone; 5=grotta mancinforte. geologia croatica 66/3geologia croatica 208 iments are entirely attributed to the faa (fig. 1b), in particular to the pelitic lithofacies (lowermost part) and to the arenitic/pelitic and pelitic/arenitic lithofacies (uppermost part). the stratigraphic position and sedimentary features of the upper deposits place them in the offida member (q1 phase sensu cello et al., 2009). 3. the subterranean camerano section 3.1. materials and methods sedimentological and lithostratigraphic description has been carried out along and across the underground levels (figs. 2, 3 and 4), and a composite sedimentological section has figure 3: views of the camerano cave system: a, b, d, e) grotta corraducci: a) and b) show entirely the “stairs” and “trionfi room” sections of figure 4, respectively; c) grotta ricotti; f) grotta gasparri-trionfi; g) grotta mancinforte. horizontal beds (a, d-g) and 5° westward inclined beds (b, c) are visible, as well as sand-clay couplets (ssc) and matrix-supported clay-clast conglomerate (arrows). bizzarri et al.: the geology of the camerano area through the reconstruction of sedimentary sequences of the urban caves geologia croatica 209 also provide a semi-quantitative grain-size analysis. with the same criteria, some clay fragments have been sampled and analysed (fig. 4). finally, nannoplankton biostratigraphy was carried out on all grotta mancinforte and grotta ricotti clay samples (fig. 4). been reconstructed. in both the grotta mancinforte and grotta ricotti sections, close sampling (about 10 cm-spacing) for each sand-clay couplet (see below) was carried out, and 1 cm2 of washed residue has been counted to provide a quantitative analysis of foraminifers (tab. 1). these samples figure 4: sedimentological and stratigraphic logs, drawn throughout the rooms, from west (left) to east (right), and along the three main cave levels. horizontal distances are not to scale. micropalaeontological and biostratigraphic samples (letters) and clay fragments samples (asterisks) are indicated. nannofossil zones refer to rio et al. (1990). geologia croatica 66/3geologia croatica 210 ta bl e 1: f or am in ife ra a ss em bl ag es in th e lo w er m os t ( g ro tt a m an ci nf or te ) a nd u pp er m os t ( g ro tt a ri co tt i) ca m er an o se ct io n (m od ifi ed a ft er l u cc io n i, 20 07 ). pe rc en ta ge fo r e ac h ta xo n is c al cu la te d on th e to ta l o f b en th ic a nd p la nk to ni c fo ra m in ife ra , r es pe ct iv el y. s =s an d le ve l; c= cl ay le ve l. sa m pl es li th ol og y be nt hi c fo ra m in ife ra (n ) pl an kt on ic fo ra m in ife ra (n ) to ta l s pe ci m en s/ cm 2 p/ b ra tio pl an kt on ic fo ra m in ife ra (% ) sp ec ie s d iv er si ty benthic foraminifera planktonic foraminifera infaunal in fa un al / ep ifa un al epifaunal ot he r b en th ic fo ra m in ife ra % g lo bi ge rin a bu llo id es % g lo bi ge rin a qu in qu el ob a % g lo bi ge rin oi de s r ub er % g lo bi ge rin oi de s s ac cu lif er % g lo bi ge rin oi de s t ril ob us % g lo bo ro ta lia cr as sa fo rm is % g lo bo ro ta lia in fla ta % g lo bo ro ta lia c fr. g r. m en ar di i % h as tig er in a sip ho ni fe ra % n eo gl ob oq ua dr in a sp p. % o rb ul in a un iv er sa % am m on ia g ro up % bu lim in a gr ou p % ca ss id ul in a sp . % m el on is sp . % pu lle ni a sp . % u vi ge rin a gr ou p % bo liv in a gr ou p % el ph id iu m g ro up % g yr oi di na a lti fo rm is % h ya lin ea b al th ic a % le nt ic ul in a sp . % lo ba tu la lo ba tu la % pa te lli na co rr ug at a % pl an ul in a ar im in en sis % q ui nq ue lo cu lin a sp . % g ro tt a ri co tt i r3 c 120 522 642 4 81 14 17 13 0 0 0 0 1 27 0 3 2 9 28 0 0 0 20 0 13 0 7 0 20 0 0 16 23 r2 c 42 336 378 8 89 12 5 0 0 0 0 0 0 24 0 5 0 36 24 0 0 7 18 0 27 0 0 0 33 0 0 0 23 r1 c 70 237 307 3 77 13 1 30 0 0 0 0 31 1 0 1 1 14 19 0 0 0 34 0 22 0 23 0 0 0 0 0 21 c4 s 129 119 248 1 48 25 6 7 0 2 0 3 0 8 2 2 8 5 32 0 8 19 24 0 11 0 38 0 18 0 7 0 3 c3 s 132 362 494 3 73 25 9 8 0 1 3 2 3 6 12 1 18 6 24 0 0 7 43 0 11 0 24 0 13 0 6 0 3 c8 c 187 607 794 3 76 25 10 5 0 3 3 4 4 3 17 1 25 1 13 2 0 10 22 0 14 0 34 0 15 0 12 1 2 c6 c 8 756 764 95 99 11 0 13 0 0 0 0 0 0 0 13 13 50 13 0 0 0 19 0 16 0 16 0 15 0 0 16 17 c5 s 15 17 32 1 53 10 20 20 0 0 0 0 0 13 7 0 0 0 20 0 7 13 0 0 41 0 29 0 0 0 0 0 29 c4* c 111 247 358 2 69 25 20 5 0 5 0 3 1 5 3 2 19 2 25 1 5 6 19 0 13 0 38 0 17 0 10 0 2 c3* s 77 304 381 4 80 18 6 6 0 0 6 1 0 4 10 0 5 4 55 1 0 0 20 0 19 0 33 1 21 0 1 1 4 c2 c 97 384 481 4 80 20 10 9 0 0 0 6 7 7 29 1 4 1 18 0 0 7 23 0 9 0 30 2 22 2 11 0 2 c1 s 58 51 109 1 47 19 10 7 0 3 0 2 2 17 9 2 7 7 28 7 0 0 14 0 12 0 24 0 35 0 6 0 10 g ro tt a m an ci nf or te a8 s 57 39 96 1 41 16 4 16 0 0 0 0 0 7 2 4 12 2 9 0 42 4 5 0 3 0 54 0 3 0 8 0 28 a7 c 267 515 782 2 66 35 3 11 2 1 0 4 1 8 14 1 6 7 27 0 0 13 23 0 22 0 30 0 12 0 6 2 4 a6 s 71 73 144 1 51 23 6 4 0 1 0 4 1 13 1 1 21 1 24 0 0 21 23 0 15 0 55 0 0 0 3 4 0 a5 c 81 74 155 1 48 20 7 5 0 1 0 0 0 26 4 2 0 20 27 0 0 7 20 0 3 0 18 0 9 0 0 9 41 a4 s 72 32 104 0 31 20 13 10 0 0 0 0 0 11 6 0 17 3 21 1 10 10 3 0 9 0 38 0 6 0 0 3 41 a3 c 188 322 510 2 63 29 1 16 9 0 1 1 4 1 14 0 15 4 15 1 0 17 33 0 14 0 17 0 20 0 10 3 3 a2 s 46 61 107 1 57 19 2 13 4 0 0 2 0 11 4 0 24 2 13 0 13 11 11 0 13 0 52 0 11 0 2 0 10 a1 c 179 247 426 1 58 38 8 7 4 2 0 2 5 6 14 2 6 7 17 0 3 16 32 0 17 0 19 0 17 2 7 2 4 b14 s 37 264 301 7 88 11 0 0 0 0 0 0 0 30 3 0 0 0 54 0 11 3 23 0 23 0 23 0 27 0 0 0 5 b13 c 165 165 330 1 50 15 6 12 0 0 0 0 0 18 12 1 0 12 27 0 6 5 21 0 24 0 24 0 0 0 0 0 30 b12 s 9 9 0 3 0 0 0 0 0 0 0 44 0 0 0 0 0 11 44 0 0 0 0 0 0 0 0 0 0 0 0 b11 c 52 146 198 3 74 14 40 0 0 0 0 0 0 2 8 2 0 6 37 2 0 4 34 0 0 0 55 0 3 0 0 1 7 b10 s 99 54 153 1 35 23 10 7 4 1 0 2 0 3 10 1 18 3 26 2 3 9 20 0 19 0 37 0 11 4 0 0 9 b9 c 199 255 454 1 56 32 1 9 2 0 2 3 5 2 16 2 15 4 22 2 0 17 27 0 22 0 25 0 11 2 8 2 2 b8 s 54 52 106 1 49 22 26 6 0 0 0 2 2 0 6 4 7 0 26 4 4 15 10 0 19 0 46 0 4 0 2 0 19 b7 c 229 327 556 1 59 33 12 9 0 1 1 3 1 8 10 0 9 8 21 2 1 12 24 0 16 0 22 0 13 1 17 2 4 b6 s 38 80 118 2 68 22 11 5 0 3 0 0 0 0 5 0 21 3 16 8 8 21 18 0 16 0 38 3 11 1 4 3 8 b5 c 128 191 319 2 60 37 2 4 1 4 0 4 2 8 4 2 4 10 32 6 1 16 25 0 11 2 26 2 8 3 10 4 10 b4 s 42 40 82 1 49 21 12 5 0 0 0 5 0 36 7 0 0 2 14 2 5 12 18 0 8 0 20 0 15 0 5 18 18 b3 c 105 81 186 1 44 29 6 7 1 0 0 4 0 20 0 4 0 1 42 0 5 11 31 0 11 1 19 1 11 4 5 5 12 b2 s 65 95 160 2 59 26 2 14 0 0 0 0 0 20 0 0 2 8 34 8 2 12 23 2 5 4 32 0 11 2 5 1 15 b1 c 158 86 244 1 35 33 0 6 4 1 1 4 2 15 1 1 1 18 29 3 2 13 0 1 8 5 19 0 14 1 0 6 47 b0 s 66 42 108 1 39 31 5 3 0 2 0 5 2 12 6 0 2 3 15 9 6 32 17 0 10 7 24 0 10 2 2 2 26 bizzarri et al.: the geology of the camerano area through the reconstruction of sedimentary sequences of the urban caves geologia croatica 211 the superposition of three main accessible cave levels (figs. 2, 3: recanatini, 1990, 1997), with their pattern of tunnels, allows one to describe a section about 30 m thick of early pleistocene marine deposits (fig. 4), and provides a three-dimensional view of depositional geometries. the recent opening of the touristic route across the caves allows completion of the stratigraphic succession, and a one-metrespaced sampling was carried out. a refinement of the preliminary micropalaeontological analyses (cf. luccioni, 2007) is also provided. sedimentary deposits are mainly lightly cemented, yellow-brown sand and grey-green clay couplets, with variable thickness and sand/clay ratios. sedimentary beds alternatively show a sub-horizontal attitude or an average 5° westward inclination (fig. 3): this feature is extremely variable along the section, and also for the same beds throughout the rooms, while interposition of tectonic disturbances has not been documented. although it may reflect the regional tectonics (main gentle south-westward dip of faa in the ancona sector), this local variability is considered here as a primary depositional feature reflecting the original gentle inclination and the irregularities of the slope. unfortunately, the interposition of erosional scars and/or unconformity surfaces has not yet been documented, and the 3d geometries of depositional bodies are hard to reconstruct. the uppermost (grotta ricotti) and intermediate cave levels are separated by about 30 m of deposits (figs. 2b, 4), only partly visible through some ventilation pits, indicating that the sand-clay alternation is continuous throughout the section. in the uppermost grotta ricotti (n. 1 in fig. 2) and in the middlelevel cave system (grotta corraducci, grotte del torrone: ns. 2 and 4 in fig. 2, respectively), two main matrix-supported gravel horizons occur, made of claystone fragments of various sizes (from 2–3 cm to 50–60 cm), dispersed in a bioclastic sandy matrix (hereafter: clay-clast conglomerate). minor clay-clast horizons are locally visible in the corraducci-trionfi-torrone complex (ns. 2, 3 and 4 in fig. 2) as well as in the lowermost grotta mancinforte (n. 5 in fig. 2). 3.2. sedimentological analysis sand-clay couplets sand-clay couplets are the main depositional feature visible in the caves. each couplet is marked at the base by an erosional surface, locally with load casts. most couplets are normally graded, from plane-paralfigure 5: main facies occurring in the studied deposits. a) sand-clay couplets: alternation of plane-parallel laminated sand and massive clay horizons (grotta corraducci). ngc=normally graded couplet; sscc= couplet with sharp sand-clay contact; rl=reverse-graded laminae; es=erosion surface; cc=clay chips. b) detail of reverse-graded laminae in sand (grotta mancinforte). c, d) matrix-supported conglomerate of clay clasts dispersed in yellow sand matrix: a-type (c, grotta ricotti) and b-type (d, grotta corraducci) clay-clast conglomerates are shown. geologia croatica 66/3geologia croatica 212 lel laminated sand to massive clay, or more rarely the sandclay transition is sharp (fig. 5a). however, the sand intervals are typically reverse graded at the base. a single couplet can vary from 10 cm to 1.5 m in thickness, and the sand/clay ratio is also variable: thickness varies from 5 cm to 1 m for sandy horizons, and from 5 to 50 cm, for clay beds. average values are about 40–50 cm and 20 cm for sand and clay horizons, respectively. the sand/ clay ratio approximately varies from 1:1 to 4:1. sand lithology is dominated by bioclastic fragments, with subordinate limestone clasts and rare quartz and chert clasts. sand grains, varying from fine to coarse sand, are 50–90% bioclasts (main ly shell fragments and benthic foraminifera), 10–50% monogenic carbonate lithoclasts, with less than 5% other lithoclasts. clay chips occur at the base of some sand horizons (fig. 5a). in their lowermost portion, most sand horizons are characterized by reverse-graded, plane-parallel laminae (figs. 5a, 5b); only rarely, do sands appear massive. patchy pseudospar cement occurs, whereas a pelitic matrix is totally absent (“washed” look). some sand horizons also show parallel cross-lamination (h ~5 cm) and/or symmetric ripple lamination in the uppermost part, but they are very rare along the section (less than 10% of the couplets). grain size gradually decreases upward, passing to silt and clay, and it is still generally marked by a parallel lamination; sharp sand/clay contacts are also documented (fig. 5a). the rare crossto ripple laminated layers are confined to some of these sand beds with sharp tops. among the mud fraction, clay largely dominates. massive clay beds are characterized by high plasticity and by a fossil content of foraminifera and other very small bioclasts. oxidation zones are present at the erosional base of many couplets, or marking sharp sand-clay transitions. oxida tion partially extends into the overlying deposits, and thus appears to represent a post-depositional (diagenetic) feature. clay-clast conglomerate – matrix-supported conglomerates are represented by claystone fragments, partially lithified and dispersed into a bioclastic sandy matrix. clay fragments are highly variable in size (from few centimetres up to 50 cm in diameter) and shape, sub-angular to sub-rounded. the claystone chips appear identical in colour, plasticity, and grain size to the interlayered clay horizons, and they are also comparable to the clay beds in terms of fossil content. the sandy matrix has the same grain size, composition, cementation as the sand beds, and comparable microfossil assemblages. two different types of conglomerate are recognizable (fig. 5): a – type: block-size conglomerate, with erosion base surface, probably channelled (figs. 3c, 5c). the size of clay clasts decreases upward, and a sort of normal gradation is documented; nonetheless, the contact with overlying sands is sharp. b – type: cobbleto pebble-size conglomerate layers, localized within sand layers (figs. 3e, 5d), with no recognizable erosion base surface. clay clasts are interposed between very coarse grained, massive sand and medium to fine grained, plane-parallel laminated sand. 3.3. palaeontological record and stratigraphic data malacofauna – the first naturalist studies of the camerano caves (procaccini ricci, 1841; de bosis, 1860) noted the abundance of fossil remains, mainly represented by marine molluscs. the major fossil horizons are observable along the cave vaults. a rich fossil collection has been gathered between 1970 and 1980, and is on display at the camerano town hall (collezione a. ruzziconi). the fossil record includes pecten jacobaeus (linnaeus), callista (callista) chione (linnaeus), glossus humanus (linna eus), venus spp., chlamys (aequipecten) opercularis (linnaeus), chlamys (flexopecten) inaequicostalis (la marck), ostrea lamellosa brocchi, scaphopods and ser pulids. although the fossil assemblage has no stratigra phic relevance, it is roughly homogeneous throughout the section and comparable to the one described by fancelli & radrizzani (1964) for the “sabbie di monte gallo” unit. foraminifera both sand and clay beds are rich in benthic and planktonic foraminifera. preliminary stratigraphic and micropalaeontological data for grotta mancinforte and grotta ricotti deposits are reported by luccioni (2007). the occurrence, from the base of the section, of frequent globorotalia inflata and rare globorotalia crassaformis constrains the whole section to the gelasian-calabrian interval. an early pleistocene age is also indicated by the common occurrence throughout the section of hyalinea balthica (baldanza et al., 2011). calcareous nannofossils the calcareous nannofossil analysis has been carried out in clay deposits, as they are totally missing in sand horizons. the nannoflora, locally very abundant and in a good state of preservation, is dominated by small gephyrocapsa, medium gephyrocapsa, large gephyrocapsa (sensu raffi, 2002), coccolithus pelagicus, helicosphaera sellii and helicosphaera carteri, and could be referred to mnn 19c and mnn19d nannofossil subzones (rio et al., 1990). nannofossil analyses constrain the camerano section to the calabrian, thus better defining the age as qm phase, as described in centamore et al. (1991) and centamore & micarelli (1991), or the q1 phase (cello et al., 2009). these data also agree with the age proposed for the top of faa in the recent carg project (sarti et al., in press). 4. discussion 4.1. palaeoecological inferences the whole malacofauna is indicative of clayey or sandy floor palaeoenvironments (peres & picard, 1964); the occurrence of the genera glossus, callista and chlamys probably reflects a minimum depth of about 40 m. furthermore, glossus indicates cool conditions at the sea floor. we suppose the lack of gastropods in the assemblage is probably due to the instability of the sea-floor. the benthic and planktonic foraminifera assemblages (tab. 1) show no remarkable differences between sand and clay horizons in the camerano sedimentary sequence, except bizzarri et al.: the geology of the camerano area through the reconstruction of sedimentary sequences of the urban caves geologia croatica 213 for specimen abundances and species diversity, which are both higher in clay beds (luccioni, 2007). the micropalaeontological content (tab. 1) shows evidence of mixed planktonic foraminifera, shallow-water (20-50 m depth) (ammonia spp., elphidium spp. and quinqueloculina spp.) and deeper water (50-100 m) benthic foraminifera (bolivina spp., bulimina spp., cassidulina spp., hyalinea balthica, uvi gerina spp., gyroidina spp.). percentages of shallow water specimens on total benthic foraminifera (tab. 1) vary from 21% to 55% in sandy beds and from 6% to 64% in clay horizons. as expected, the p/b ratio is significantly higher for clay beds: nevertheless, in 60% of the sand beds, the p/b ratio is ≥1, evidencing an anomalous enrichment in the plank tonic component for sandy deposits (tab. 1). thus, sand -clay couplets reasonably document resedimentation/remobilization events, followed by the re-establishment of low-energy conditions, while clay horizons document resedimentation, distal river supply and water-column productivity of biota. as a result of remobilization, a gradual transition is expected in clay beds, from a reworked microfauna assemblage at the base, to an assemblage at the top dominated by water-column productivity. unfortunately, the avail able data do not allow documentation of this variation; more detailed analyses are needed. benthic foraminifera assemblages (average values of about 33% of shallow-water taxa and about 25% of deeper water taxa), as well as plankton/benthos ratios (tab. 1), indicate a shallow-water sandy sea floor, distally connected to a deeper (up to 100 m) clayey floor (circa-littoral to upper bathyal zones). cold-water planktonic foraminifera, such as globorotalia inflata, globigerina bulloides and neogloboquadrina spp., consistently occur in the assemblage with temperate to warm water specimens (globigerinoides spp., orbulina universa) (tab. 1). through the deeper benthic foraminifer assemblages, the abundance of bolivina spp., bulimina spp., cassidulina spp., hyalinea balthica and lenticulina spp. also indicates that the basin-floor environment underwent low-oxygenated, cool-water conditions (baldanza et al., 2011). this situation is probably related to water-mass stratification and thermal isolation of the basin floor. 4.2. sedimentological interpretation according to fossil content and sedimentary features, deposits are referred to an open marine environment, mainly below and only occasionally across the storm wave base, as testified by the extreme rarity of wave-induced structures; nonetheless, some clay should be discussed. clay beds reflect a suspension-dominated offshore marine environment. on the other hand, considering the micropaleontological assemblages, sandy beds clearly show evidence of mixing of proximal (both epifaunal and infaunal) and distal benthic taxa. the clay source is distal river sedimentation and/or intrabasinal remobilization rather than ancient conero “island” beach systems. except for the argillaceous oligocene schlier fm., the limestone/marly limestone units outcropping in the present-day m. conero anticline, could not produce the large amount of clay in pliocene to pleistocene marine deposits. moreover, in the camerano deposits, cretaceous to miocene reworked microfossils are very rare. sands are mainly reverse-graded, plane-parallel laminat ed. plane-parallel lamination in sandy deposits may be indicative of various sedimentary environments; nevertheless, reverse grading more commonly occurs in sediment gravity flow deposits than in current/wave deposits. sandy storm deposits may be parallel-laminated in the basal portion (plane beds). as a storm subsides a decrease of energy, from erosive capacity to critical and subcritical flow, to the final recovering of fair-weather conditions, should produce a suite of sedimentary structures, from hcs to swaley-laminations, to wave ripples. except for the rare occurrence of small scale cross-lamination and/or wave ripples, these structures are not documented through the camerano section. the hypothesis that sand-clay couplets are shelf storm deposits seems unsatisfactory. plane-parallel laminated, reverse-graded sands can be identified as facies f7 (mutti, 1992) or s1 (lowe, 1982), both described from siliciclastic turbidites, and are comparable to the “traction carpets” described in sandstones (dzu­ lynski & sanders, 1962; middleton, 1970, 1993; hiscott & middleton, 1979; lowe, 1982; todd, 1989; sohn, 1997). on the other hand, the sands are largely bioclastic. a study on the hydraulic equivalence between bioclasts and lithoclasts of different lithology is beyond the scope of this work; nevertheless, bioclastic and lithoclastic sands should behave similarly during the formation of “traction carpets”. both facies s1 (lowe, 1982) and f7 (mutti, 1992) in siliciclastic deposits are attributed to “high density turbidity currents”. sandy beds presumably represent basinal resedimentation of nearshore bioclastic sands, promoted by storm-induced turbidity currents. the lack of clay matrix in the sandy beds is probably due to the flow conditions during the event, and to a negligible original amount of clay in nearshore remobilized deposits, according to a mechanism resembling the one proposed for ‘carbonate turbidites’ (colacicchi & baldan za, 1986). thus, the gradual to sharp transition to clay mainly represents the more or less gradual or rapid re-establishment of low-energy conditions. the physical characters (colour, plasticity, textural features) and the microfossil content (see below) are unvarying across clay beds, as well as in clay chips at the base of couplets. in each couplet, a clay content reasonably derives from erosion of clay-floor sediments, entrapment of clay chips and resedimentation of fines during the turbiditic event (enos, 1969). nevertheless, this “turbidi te” clay fraction is indistinguishable from the true hemipela gite (fig. 6a). this interpretation looks reasonable; however, some issues are to be considered. the carbonate tur bidites are typically fed by a carbonate platform system, which provides the biogenic component. the question is, if a submerged beach, in a siliciclastic context, may export basin-ward carbonate sand with a relevant amount of bioclasts. the origin of sand is presumably local, and the most reasonable explanation is that m. conero island and its pliocene to pleisto cene calcarenitic beaches were the main source area for san dy deposits (fig. 6). in fact, bioclastic calcarenitic beaches are documented in the area, at least during the early pliocene (“trave horizon”: e.g. cantalamessa et al., 1986; centamore & micarelli, 1991; sarti et al., in press). geologia croatica 66/3geologia croatica 214 the lack of clay matrix in the sandy beds is a critical point in interpreting sand-clay couplets as turbidites. in fact, the suspended silt/clay fraction (or micrite in carbonate turbidites: colacicchi & baldanza, 1986) plays a significant role in the turbulent flow movement. the occurrence of beds showing gradation from sand to clay (ngc in fig. 5a) seems to demonstrate that clay was initially present in the suspension together with sand. the sand/clay separation may derive from flow partition between a lower laminar layer (i.e., flowing grain layer) and an upper turbulent layer (i.e., turbidity current). in this case, sand layers may be better defined as grain flow deposits, while only the upper, very fine sand to clayey part of graded couplets can be considered a true turbidite (sanders, 1965; postma et al., 1988; san ders & friedman, 1997; mulder & alexander, 2001; shanmugam, 2002). the occurrence of both graded and sharp sand-clay transition indicates that the original sediment gravity flow may or may not reach the conditions for internal stratification. thus, not all the flows evolve as turbidity currents, and the sharp transition could represent the successive settlement of suspended clay above a grain flow deposit. b-type clay-clast conglomerates seem to be integral parts of the sand layers. sedimentary features resemble those in the experiments of postma et al. (1988) on high-density turbulent flows, except for the larger scale of clay clasts in camerano deposits. according to that model, deposition originates in consequence of density stratification of the flow. b-type conglomerate might result from storm-induced, highdensity turbidity currents. a-type clay-clast conglomerates are identifiable as debrites (sensu stow, 1985), deriving from remobilization of semi-lithified clay beds and unlithified sands. thus, they are interpreted as debris-flow deposits. slope failure can produce debris flows directly, if internal cohesion is lost, even on gentle slopes (dott, 1963; rodine & johnson, 1976), or debris flows may derive from distal evolution of other massmovements (lowe, 1982; nemec & steel, 1984; stow, 1985; mutti, 1992; mulder & alexander, 2001; dasgupta, 2003). the original clay amount is probably a leading factor in debris flows (hampton, 1975). however, clay in the conglomerates of the camerano section is confined to large clay clasts, and none is present within the sandy matrix. the lack of cohesion in unlithified sand beds should facilitate initiation of flows. finally, some considerations about the relationship between clay-clast conglomerates and sand-clay couplets are proposed. grain flows/turbidites may be induced in sands both by down-current evolution of debris flows (hampton, 1972; mutti, 1992; ilstad et al., 2004a; elverhøi et al., 2010) or promoted by storm events (walker, 1984). the amount of clay in the initial mixture is critical for debris-flow movement along a low-inclination slope (less than 2% of clay to maintain a fine-sand debris flow, up to 19% for coarse-sand debris flow, according to hampton, 1975), as well as for the features of evolving flow caused by water intrusion (hampton, 1972, 1975; post ma et al., 1988; ilstad et al., 2004a; elverhøi et al., 2010). thus, the clay-clast conglomerates may result from disturbance and mass failures of semi-lithified beds by overloading or earthquakes rather than storm-induced hydraulic pressures. in this scenario, sand-clay couplets and clay-clast conglomerates result from different processes acting on a gentle, but unstable, slope (fig. 6a). figure 6: basin and palaeoenvironmental reconstruction, according to the alternative proposed sedimentation models (see text). a) gentle sloped outer shelf, with alternate sediment gravity flows deposits (sands) and offshore clay deposits, and occurrence of seismic-induced debrites (conglomerates). b) alternative interpretative model for a-type and b-type clay gravel. seismic-induced slumps (not documented in the camerano section) remobilizing bioclastic sand and cohesive clay horizons, evolving basin-ward to matrix-supported gravel. swb = storm wave base. bizzarri et al.: the geology of the camerano area through the reconstruction of sedimentary sequences of the urban caves geologia croatica 215 in an alternative interpretation, both aand b-type conglomerates, as well as sand-clay couplets, may originate from the distal modification of slumps (fig. 6b). slump deposits have not yet been found in the camerano section or in the neighbouring areas, however. the two gravel types could be interpreted as more proximal (a) and distal (b) slump deposits, respectively (fig. 6b). slumps were most likely induced by seismic activity, and clay beds acted as detachment levels along a gentle slope. nevertheless, clay does not occur within the matrix, which is solely bioclastic sand. the seismic shock probably mobilized semi-lithified sand-clay couplets, which started moving as a unique body. low-permeability clay layers are responsible for the increase in fluid pressure as pore water is expelled from underlying sand beds under shear stress (sturm, 1971; hampton, 1972; maltman, 1994; hamp ton et al., 1996; strachan, 2002; ilstad et al., 2004b; sultan et al., 2004). pore-water pressure causes slumps on very low slopes (field et al., 1982; mcadoo et al., 2000; strachan, 2002; garcia-tortosa et al., 2011; alsop & marco, in press). slumps distally evolved to non-cohesive debris flows (sensu lowe, 1982 and ne­ mec & steel, 1984), mainly supported by buoyancy and dispersive pressure mechanisms, rather than by cohesion. lar ge clay clasts were preserved during the motion, a very short transport. this slump model (fig. 6b) is comparable to the one proposed by colacicchi & monaco (1994) for the cretaceous-palaeogene scag lia basin. if the debris flow continues incorporating water, the dilution may promote a high -density turbidity current, with flow density stratification (sanders, 1965; hamp ton, 1972, 1975; postma et al., 1988; sanders & friedman, 1997; shanmugam, 2002; ilstad et al., 2004a; elverhøi et al., 2010). during this evolution, the sand-clay couplets are probably sedimented, as turbidity currents and/or grain flows are succeeded by settlement of suspended clay. 4.3. facies interpretation the alternating sand/clay beds, characteristic of the uppermost deposits of the camerano hill sedimentary succession, observable only in the subterranean outcrops, are very similar to the arenitic/pelitic or pelitic/arenitic lithofacies belonging to the faa (sarti et al., in press). there are, however, some important differences between the camerano and typical faa lithofacies. compared to the faa, massive sand beds in the camerano sedimentary sequence are rare, large-scale cross-lamination and hummocky geometries are totally lacking, sand is dominantly plane-parallel laminated and reverse graded, and clay beds are massive rather than thin-laminated. on the other hand, the sand/clay ratio is the sedimentological feature most comparable with the ones exhibited by arenitic/pelitic lithofacies in deposits cropping out west of camerano and by the offida member (cello et al., 2009; sarti et al., in press). sand lithology is dominated by bioclastic fragments, with subordinate lithics, indicating that sediments were locally derived. deposits referable to slump evolution were formerly reported in deposits from the western flank of the periadriatic basin (cantalamessa et al., 1986; di celma et al., 2010; di celma, 2011), but were never documented before in the eastern area and in early pleistocene deposits. finally, according to our interpretation, both sand-clay couplets and clay-clast conglomerate, cannot be related to the shoreface and/or offshore transition deposits recognized by sarti et al. (in press) in the camerano area, and are most likely resedimented in a deeper basin environment (outer shelf). 4.4. palaeoenvironmental reconstruction sedimentological evidence indicates that the camerano sedimentary sequence was deposited in a shallow outer shelf (fig. 6a), positioned in close proximity to a partially emergent structural high, an island, today partially identifiable with mt. conero. this sandy shoreface to inner shelf environment represented the source of the carbonate sand. deposits were moved offshore by storm waves, and resedimented to the outer shelf by storm-induced turbidity currents, debris flows and grain flows. due to their carbonate composition and the richness in bioclasts, a local origin for sandy deposits is presumed. the outer shelf/basin was characterized by deposition of clay, presumably supplied by distant western river deltas, mixed with primary productivity within the water column. in addition, an integrated submarine-canyon and basin system is documented in the southwestern periadriatic basin, during the early pleistocene at least (di celma et al., 2010; di celma, 2011). a local contribution to clay from this source cannot be excluded. the close variability of sub-horizontal and 5° westward inclination for sedimentary beds could reflect an original gently inclined, irregular slope. irregularities may be the consequence of 3d geometries of larger sediment gravity flow deposits (debrites). the outer shelf periodically received shallow-water carbonate near-shore sediments, remobilized from the eastern inner shelf by storm events and resedimented as carbonate turbidites of high density and/or grain flow deposits. these sediment gravity flows also partially eroded clay beds, and clay was involved in the resedimentation events. from miocene times onward the marches area underwent a tectonic compressive regime and seismic activity; the occurrence of seismic-induced debris flow deposits and/or slump deposits, recorded as conglomerates in the camerano succession (fig. 6), documents sedimentation in a tectonically active context, continuing throughout the early pleistocene. 5. conclusions thanks to the exceptional underground town of camerano it is possible to describe a composite sedimentological and stratigraphic section of early pleistocene marine deposits (mnn 19c and 19d nannofossil subzones), that are lacking suitable subaerial outcrops. additionally, superposition of different cave levels and the complex pattern of tunnels provide a unique three-dimensional view of depositional geometries, facies heterogeneity, and succession. relative to the usual faa features, facies described through the camerano section show some peculiarities; moreover, some contradictory characteristics have been described, and not all of them can be easily interpreted. deposits are clearly marine, and geologia croatica 66/3geologia croatica 216 they are not referable to the alternation of foreshore/backshore deposits and brackish deposits, recognized in the area by sarti et al. (in press). due to the dominance of planktonic foraminifera, deposition on a nearshore environment has been excluded, and an outer shelf environment is more probable. the lack of typical storm-related structures, such as hcs, swaley cross-lamination, etc., indicate the sand-clay couplets are not tempestites. thus, deposits are interpreted herein as sediment gravity-flow deposits, mainly initiated by storm events, above storm-wave base. on the basis of facies analysis and sedimentological inferences, we constructed a sedimentation model and hypothesized the palaeoenvironmental context for the deposition of the camerano sedimentary sequence (fig. 6). sand-clay couplets are described as storm-induced carbonate turbidites of high density and/or grain flow deposits, and matrix-supported conglomerate of clay clasts are interpreted as debrites. if they were produced by debris flows or distal evolution of slumps, the conglomerates, particularly the a-type, suggest that sedimentation occurred in an unstable, probably tectonically active, outer-shelf environment. palaeoecological data indicate a depth range from 40 to about 100 m, supporting the hypothesis of a shallow outershelf environment. clay horizons were apparently supplied from distal river deltas to the west, enriched by planktonic pelagic sedimentation. storm-induced carbonate turbidites periodically carried proximal bioclastic material from the western coast of mt. conero “island” (fig. 6). large clay fragments from matrix-supported conglomerates, probably derived from seismic remobilization of partially lithified deposits along the inner shelf, although their provenance is not clearly determinable. the microfossil record is consistent with the inferred palaeoenvironmental reconstruction. nevertheless, some uncertainty remains about some apparently conflicting aspects (relatively shallow depth, low slope, lack of clay matrix in “turbidites”, source area, rare occurrence of symmetrical cross-lamination), and other studies are need ed. overall, the data presented in this study greatly improve the geological knowledge of the camerano caves and surrounding territory. acknowledgement the authors would like to thank the people of the pro loco “carlo maratti”, the camerano tourist agency office (iat) and the camerano municipality for their kindness and cooperation during this project. we are also indebted to dr. keegan e. alagna for the friendly revision of the manuscript and the useful suggestions. authors are also grateful to prof. paul enos for his useful critical reading of the manuscript, and to the two reviewers for their comments and suggestions. references alsop, g.i. & marco, s. (in press): seismogenic slump folds formed by gravity-driven tectonics down a negligible subaqueous slope.– tectonophysics (2013), doi: 10.1016/j.tecto.2013.04.004 baldanza, a., bizzarri, r. & hepach, h. (2011): new biostratigraphic data from the early pleistocene tyrrhenian paleocoast (western umbria, central italy).– geol. croat., 64/2, 133–142, doi: 10.4154/gc.2011.11 bigi, s., cantalamessa, g., centamore, e., didaskalou, p., micarelli, a., nisio, s., pennesi, t. & potetti, m. (1997): the periadriatic basin (marche-abruzzi sector, central italy) during the plio–pleistocene.– g. geol., 59, 245– 259. boccaletti, m., calamita, f., centamore, e., chiocchi­ ni, u., deiana, g., micarelli, a., moratti, g. & potet­ ti, m. (1986): evoluzione dell’appennino tosco umbro marchigiano durante il neogene.– gior. geol., 48/1, 227–233. boccaletti, m., cerrina faroni, a., martinelli, p., mo­ ratti, g., plesi, g. & sani, f. (1991): l’alternanza distensionecompressione nel quadro evolutivo dei bacini neogenici dell’appennino settentrionale.– studi geol. cam., vol. spec. 91/1, 187–192. calamita, f., cello, g., centamore, e., deiana, g., mica­ relli, a., paltrinieri, w. & ridolfi, m. (1991): stile deformativo e cronologia della deformazione lungo tre sezioni bilanciate dall’appennino umbro-marchigiano alla costa adriatica.– studi geol. cam., vol. spec. 91/1, 295–314. cantalamessa, g., centamore, e., chiocchini, u., cola­ longo, m.l., micarelli, a., nanni, t., pasini, g., potet­ ti, m. & ricci lucchi, f. (1986): il plio-pleistocene delle marche.– in: centamore, e. & deiana, g. (eds.): la geologia delle marche. studi geol. cam., vol. spec. 73� congresso soc. ge-studi geol. cam., vol. spec. 73� congresso soc. geol. it., 61–68. cantalamessa g. & di celma, c. (2004): sequence response to syndepositional regional uplift: insights from high-resolution sequen ce stratigraphy of late early pleistocene strata, periadriatic basin, central italy.– sedimentary geology, 164, 283–309. doi: 10.1016/j.sedgeo.2003.11.003 cantalamessa, g., centamore, e., didaskalou, p., micarelli, a., napoleone, g. & potetti, m. (2002): elementi di correlazione nella successione marina plio-pleistocenica del bacino periadriatico marchigiano.– studi geol. cam. nuova ser., 1, 33–50. cello, g., coccioni, r., gazzani, d., nesci, o., pennacchioni, e., piccini, m., riccioni, m., sampaolesi., s., tondi, e., critelli, s., le pera, e., negri, a., didaskalou, p., potetti, m., savelli, d., farabollini, p., mazzoli, s. & d’angeli, t. (2009): note illustrative della carta geologica d’italia alla scala 1:50.000-foglio 303 “macerata”.– ispra, 90 p. centamore, e., cantalamessa, g., micarelli, a., potet­ ti, m., berti, d., bigi, s., morelli, c. & ridolfi, m. (1991): stratigrafia ed analisi di facies dei depositi del miocene e del pliocene inferiore dell’avanfossa marchigiano-abruzzese e delle zone limitrofe.– studi geol. cam., vol. spec. 91/2, 125–131. centamore, e., farabollini, p. & angelini, s. (2009): guida all’escursione:”geologia e geomorfologia del settore fermano nel bacino periadriatico marchigiano-abruzzese”.– rend. online soc. geol. it., 8, 162–168. centamore, e. & micarelli, a. (1991): stratigrafia.– in: l’ambiente fisico delle marche, geologia, geomorfologia, idrogeologia. selca, firenze, 1–66. centamore, e. & nisio, s. (2003): significative events in the periadriatic foredeeps evolution (abruzzo-italy).– studi geol. cam., vol. spec. 73� congresso soc. geol. it., 39–48. colacicchi, r. & baldanza, a. (1986): carbonate turbidites in a mesozoic pelagic basin: scaglia formation, apennines, comparison with siliciclastic depositional models.– sedim. geol., 48, 81–105. doi: 10.1016/0037-0738 colacicchi, r. & monaco, p. (1994): pure carbonate gravity flow deposits of the scaglia basin compared with central apennine siliciclastics (marnoso-arenacea and laga): analogies and differences.– mem. sc. geol., 46, 25–31. bizzarri et al.: the geology of the camerano area through the reconstruction of sedimentary sequences of the urban caves geologia croatica 217 colalongo, m.l., nanni, t. & ricci lucchi, f. (1979): sedimentazione ciclica nel pleistocene anconetano.– geol. romana, 18, 71–93. dasgupta, p. (2003): sediment gravity flow the conceptual problems.– earth-sci. rev., 62, 265–281, doi: 10.1016/s0012-8252(02)00160-5 de bosis, f. (1860): ancona e dintorni. cenni di storia naturale.– ancona. di celma, c. (2011): sedimentology, architecture, and depositional evo lution of a coarse-grained submarine canyon fill from the gelasian (early pleistocene) of the peri-adriatic basin, offida, central italy.– sediment. geol., 238/3–4, 233–253. doi: 10.1016/j.sedgeo.2011.05.003 di celma, c. & cantalamessa, g. (2012): off-shelf sedimentary record of recurring global sea-level changes during the pliopleistocene: evidence from the cyclic fills of exhumed slope systems in central italy.– journal of the geological society, 169/6, 630–643. doi: 10.1144/jgs2012-041 di celma, c., cantalamessa, g., didaskalou, p. & lori, p. (2010): sedimentology, architecture, and sequence stratigraphy of coarse-grained, submarine canyon fills from the pleistocene (gelasian-calabrian) of the peri-adriatic basin, central italy.– marine and petroleum geology, 27/7, 1340–1365. doi: 10.1016/j.marpetgeo. 2010.05.011 dott, r.h. jr. (1963): dynamics of subaqueous gravity depositional processes.– american association of petroleum geologists bull., 47/1, 104–128. dzulynski, s. & sanders, j.e. (1962): current marks on firm mud bottoms.– trans conn. acad. arts set., 42, 57–96. elverhøi, a., breien, h., de blasio, f.v., harbitz, c.b. & pagliardi, m. (2010): submarine landslides and the importance of the initial sediment composition for run-out length and final deposit.– ocean dynamics, 60, 1027–1046, doi: 10.1007/s10236-010-0317-z enos, p. (1969): anatomy of a flysch.– j. sediment. petrol., 39/2, 680–723. fancelli, r. & radrizzani, s. (1964): note illustrative della carta geologica d’italia del foglio n�118 – ancona.– serv. geol. it., ro ma. field, m.e., gardner, j.v., jennings, a.e. & edwards, b.d. (1982): earthquake-induced sediment failures on a 0.25° slope, klamath river delta, california.– geology, 10, 542–546. garcia-tortosa, f.j., alfaro, p., gilbert, l. & scott, g. (2011): seismically induced slump on an extremely gentle slope (<1�) of the pleistocene tecopa paleolake (california).– geology, 39, 1055–1058. hampton, m.a. (1972): the role of subaqueous debris flow in generating turbidity currents.– j. sediment. petrol., 42/4, 775–793. hampton, m.a. (1975): competence of fine-grained debris flows.– j. sediment. petrol., 45/4, 834–844. hampton, m.a., lee, h.j. & locat, j. (1996): submarine landslides.– rev. geophys., 34/ 1, 33–59. hiscott, r.n. & middleton, g.v. (1979): depositional mechanics of thick-bedded sandstones at the base of a submarine slope, tourelle formation (lower ordovician), quebec, canada.– in: doyle, r.j. & pilkey, o.h. (eds.): geology of continental slopes. sepm spec. publ., 27, 307–326. doi: 10.2110/pec.79.27.0307 ilstad, t., elverhøi, a., isslera, d. & marr, j.g. (2004a): subaqueous debris flow behaviour and its dependence on the sand/clay ratio: a laboratory study using particle tracking.– mar. geol., 213, 415–438. doi: 10.1016/j.margeo.2004.10.017 ilstad, t., marr, j.g., elverhøi, a. & harbitz, c.b. (2004b): laboratory studies of subaqueous debris flows by measurements of pore-fluid pressure and total stress.– mar. geol., 213, 403–414. doi: 10.1016/j.margeo.2004.10.016 lowe, d.r. (1982): sediment gravity flows ii. depositional models with special reference to the deposits of high-density turbidity currents.– j. sedim. petrol., 52/1, 279–297. doi:10.1306/212f7f31-2b2411d7-8648000102c1865d luccioni, i. (2007): geologia ipogea di camerano – storia della città sotto la città.– collana: quaderni di storia cameranese, castelfidardo, 115 p. maltman, a. (1994): deformation structures preserved in rocks.– in: maltman, a. (ed.): the geological deformation of sediments. london, chapman & hall, 261–307. mcadoo, b.g., pratson, l.f. & orange, d.l. (2000): submarine landslide geomorphology, us continental slope.– mar. geol., 169/1-2, 103–136. micarelli, a., cantalamessa, g., didaskalou, p., potet­ ti, m., pambianchi, g., le pera, e., critelli, s., pennesi, t. & mazzoli, s. (in press): carta geologica d’italia – foglio 314 “montegiorgio”. note illustrative – ispra, roma, 90 p. middleton, g.v. (1970): experimental studies related to problems of flysch sedimentation.– in: lajoie, j. (ed.): flysch sedimentology in north america. geol. assoc. can. spec. pap., 7, 253–272. middleton, g.v. (1993): sediment deposition from turbidity currents.– ann. rev. earth planet. sc., 21, 89–114. doi:10.1146/annurev.ea.21.050193.000513 mulder, t. & alexander, j. (2001): the physical character of subaqueous sedimentary density flows and their deposits.– sedimentology, 48/2, 269–299. doi: 10.1046/j.1365-3091.2001.00360.x mutti, e. (1992): turbidite sandstones.– agip, milano, 275 p. nanni, t., pennacchioni, e. & rainone, m.l. (1986): il bacino pleistocenico marchigiano.– in: “atti riunione gruppo sedimentologia cnr, ancona, 5-7 giugno 1986”, 13–43. nemec, w. & steel, r.j. (1984): alluvial and coastal conglomerates: their significant features and some comments on gravelly mass flow deposit.– in: koster, e.h. & steel, r.j. (eds.): sedimentology of gravels and conglomerates. canadian society of petroleum geologists memoir, 10, 1–31. ori, g.g & friend, p.f. (1984): sedimentary basins formed and carried piggyback in active thrust sheets.– geology, 12, 475–478. doi: 10.1130/0091-7613(1984)12<475:sbfacp>2.0.co;2 ori, g.g., serafini, g., visentin, c., ricci lucchi, f., casnedi, r., colalongo, m.l. & mosna, s. (1991): the pliocene pleistocene adriatic foredeep (marche and abruzzo, italy): an integrated approach to surface and subsurface geology.– 3rd e.a.p.g. conference, adriatic foredeep field trip guide book, 26-30/05/91, firenze. pérès, j.m. & picard, j. (1964): nouveau manuel de bionomie benthique de la mer méditerranée.– recueil des travaux de la station marine d’endoume, marseille, 47/31, 3–137. postma, g., nemec, w. & kleinspehn, k.l. (1988): large floating clasts in turbidites: a mechanism for their emplacement.– sediment. geol., 58, 47–61. doi: 10.1016/0037-0738(88)90005-x procaccini ricci, v. (1841): descrizione del monte della crescia e del monte san pietro. senigallia. raffi, i. (2002): revision of the early – middle pleistocene calcareous nannofossil biochronology (1.75 – 0.85 ma).– mar. micropal., 45, 25–55. doi: 10.1016/s0377-8398(01)00044-5 recanatini, a. (1990): le grotte di camerano.– collana: quaderni di storia cameranese, castelfidardo, 85 p. recanatini, a. (1997): le grotte del conero. ricerche di speleologia archeologica nel parco del conero.– collana: i voli del conero, 4, utj, jesi, 254 p. recanatini, a. (2000): la città segreta, correlazioni tra sviluppo urbano di superficie e rete ipogea nei centri storici alle falde del conero. il caso di camerano e osimo.– in: “atti del convegno: la memoria del sottosuolo. camerano 17/18 luglio 1999. cavità artificiali e sistemi ipogei sotto i centri storici alle falde del conero ed in area mesoadriatica.” jesi, 169–202. ricci lucchi, f. (1986): the oligocene to recent foreland basins of the northern apennines.– spec. publs. int. ass. sediment., 8, 105–139. doi: 10.1002/9781444303810.ch6 geologia croatica 66/3geologia croatica 218 rio, d., raffi, i. & villa, g. (1990): pliocene-pleistocene calcareous nannofossil distribution patterns in the western mediterranean.– in: kastens, k. & mascle, j. (eds.): proc. odp sc. res., 107, 513–533. doi:10.2973/odp.proc.sr.107.164.1990 rodine, j.d. & johnson, a.m. (1976): the ability of debris heavily freighted with coarse clastic materials, to flow on gentle slopes.– sedimentology, 23/2, 213–234. doi: 10.1111/j.1365-3091.1976. tb00047.x sanders, j.e. (1965): primary sedimentary structures formed by turbidity currents and related resedimentation mechanisms.– in: middleton, g.v. (ed.): primary sedimentary structures and their hydrodynamic interpretation.– sepm spec. publ., 12, 192–219. sanders, j.e. & friedman, g.m. (1997): history of petroleum exploration in turbidites and related deep-water deposits.– northeastern geology and environmental sciences, 19/1–2, 67–102. sarti, m., coltorti, m., budini, a., mattioni, l., pieruccini, p., rossini, l., giunta, s. & negri, a. (in press): carta geologica d’italia foglio 293 “osimo”. note illustrative ispra, roma, 140 p. shanmugam, g. (2002): ten turbidite myths.– earth-sci. rev., 58, 311– 341. doi: 10.1016/s0012-8252(02)00065-x sohn, y.k. (1997): on traction-carpet sedimentation.– j. sedim. res., 67, 502–509. doi:10.1306/d42685ae-2b26-11d78648000102c1865d stow, d.a.v. (1985): deep-sea clastic sediments.– in: brenchley, p.j. & williams, b.p. j. (eds.): sedimentology, recent developments and applied aspects. blackwell, london, 67–93. strachan, l.j. (2002): slump-initiated and controlled syndepositional sandstone remobilization; an example from the namurian of county clare, ireland.– sedimentology, 49, 25–41. sturm, e. (1971): subaqueous slump structures.– geol. soc. am. bull., 82/2, 481–484. doi: 10.1130/0016-7606(1971)82[481:sss]2.0.co;2 sultan, n., cochonat, p., canals, m., cattaneo, a., dennielou, b., haflidason, h., laberg, j.s., long, d., mienert, j. &trincardi, f. (2004): triggering mechanisms of slope instability processes and sediment failures on continental margins: a geotechnical approach.– mar. geol., 213/1–4, 291–321. todd, s.p. (1989): stream-driven, high-density gravelly traction carpets: possible deposits in the trabeg conglomerate formation, sw ireland and some theoretical considerations of their origin.– sedimentology, 36, 513–530. doi: 10.1111/j.1365-3091.1989.tb02083.x walker, r.g. (1984): facies models.– geosciences canada, 317 p. manuscript received august 11, 2012 revised manuscript accepted july 29, 2013 available online october 5, 2013 03 kuhta.indd 41 �ab stra ct spring hydrographs and thermographs are a direct refl ection of all processes that occur within aquifer systems. therefore, they contain signifi cant information about the hydrogeological characteristics of such systems. this article analyses hydrographs and thermographs from four springs located in the foothills of the mt. biokovo massif in southern croatia. these springs are recharged by carbonate aquifers. monitoring of yields and groundwater temperatures, as well as analysing hydrograph recessions, daily discharge and rainfall time series and water temperature dynamics, facilitated the identifi cation of the main properties of the aquifer system located in the hinterland of the individual springs. signifi cant differences in the recharge mechanisms of individual springs were determined to be a consequence of varying geological conditions, degree of karstifi cation and conduit network characteristics. the results suggest that the cretaceous and palaeogene basinal carbonate deposits (kotišina limestones and breccias), the hydrogeology of which has not yet been studied, have the characteristics of permeable karstic rocks. keywords: karst hydrogeology, spring hydrograph, time series analysis, biokovo hydrodynamic characteristics of mt. biokovo foothill springs in croatia � mladen kuhta, andrej stroj and željka brkić department of hydrogeology and engineering geology, croatian geological survey, sachsova 2, 10 000 zagreb, croatia; (mkuhta@hgi-cgs.hr, astroj@hgi-cgs.hr, zbrkic@hgi-cgs.hr) doi: 104154/gc.2012.03 geologia croatica 65/1 41–51 6 figs. 3 tabs. zagreb 2012 geologia croaticageologia croatica 1. introduction a spring hydrograph is a direct refl ection of all the physical processes that infl uence groundwater fl ow within an aquifer. hydrographs of karst springs are characterised by pronounced, sudden changes of discharge, and a briefl y delayed response to rainfall (bonacci 1987, 1993; goldscheider et al., 2007), which differentiates them from hydro graphs of springs that drain other aquifers, i.e. fi ssured and intergranular aquifers (fig. 1). rapid spring responses to rainfall occur mainly as a result of sudden infi ltration to conduit systems related to the function of the subcutaneous (epikarst) zone (mangin, 1975; williams, 1983, 2008; pronk et al., 2009). when rainfall ceases, a sudden increase in fl ow is initially followed by a nearly equal sudden decrease, after which the decrease gradually slows, refl ecting an alteration in the system dynamics. hydrographs, therefore, refl ect the characteristics of two main types of fl ow in an aquifer: fast-fl ow, which is determined by conduit systems and rainfall distribution properties, and base-fl ow, which is predominantly controlled by slow drainage of low hydraulic conductivity volumes in the aquifer (atkinson, 1977; padilla et al., 1994). thus, the shape of a hydrograph is a signifi cant indicator of an aquifer’s characteristics and serves as the most important time series in analyses of the hydrogeological characteristics of karstic aquifers. the makarska coast area extends along approximately 53 km of the central dalmatian coastline along the foothills and slopes of the mt. biokovo massif that stretches from brela in the north to gradac in the south (fig. 2). this area is most ly supplied with water from the regional water supply system, which intakes water from the cetina river near zadvarje. this system is important during dry periods, when tourism raises the demand for drinking water. in addition, the water supply system of the makarska coast includes six smaller water intakes built on the springs along the base of mt. biokovo. these intakes include the springs of baška voda, makarski vrutak, orašje, grebice, podgorski vrutak and izbitac in drašnice. although their total yield during the summer is far below the actual consumption rate, the captured springs signifi cantly contribute to the stability of the geologia croatica 65/1geologia croatica 42 public water supply system, especially because the amount of water in the regional system from the cetina river is technically limited. during the tourist off-season, and particularly during favourable hydrological periods, the local water intakes alone satisfy the majority of water demands. these springs are especially signifi cant due to their location high above the urban areas, which facilitates gravitational fl ow. the majority of the springs on the southern slopes of mt. biokovo have not been investigated, and data on their yield and hydrogeological characteristics were based on the empirical insight of the makarska water utility company. thus, during investigations to identify sanitary protection zones for springs used in the public water supply system, special attention was paid to the establishment of a system to continuously monitor yields at the technically adequate water intakes, including the springs of makarski vrutak, orašje, podgorski vrutak and izbitac in drašnice. these data enabled hydrograph analyses to be made. 2. geological and hydrogeological settings the dinaric karst is characterized by a succession of more than 8000 m of predominantly carbonate sediments (tišljar et al., 2002; velić et al., 2002), that was deposited and exposed to intense tectonic disturbances in several phas es from the triassic period until the present. the main deformation episode began in the late cretaceous, when synsedimentary tectonics became stronger, reaching a maximum in the oligocene/miocene. this led to tangential movements and uplift of the dinarides, including the mt. biokovo area. due to the strong ne–sw-oriented regional tectonic stress, the main resulting structures, including folds, faults, thrusts and imbricate structures, are of the nw–se strike (i.e., the dinaric strike). later orogenic movements shifted the region al tectonic stress to the n–s and caused wrench tectonic deformations. the main part of the mt. biokovo massif consists of shallow-water carbonates, mostly limestones with subordinate dolomites, deposited in the period from the lower juras sic to the upper cretaceous (fig. 3). the basic structural form defi nes a large and prominent biokovo anticline (marinčić et al., 1977) in the southwest. this anticline is in tectonic contact with highly deformed limestones that contain pelagic elements and carbonate breccias of the upper cretaceouspalaeogene, (i.e., the kotišina deposits) and/or a narrow belt of tectonically reduced fl ysch deposits. jelaska et al. (2003) proposed a name for this basinal domain: the kotišinatilovica trough. palaeogeographically, this trough represents a nw embayment of the budva-cukali basin (chorowicz, 1975). basinal carbonate deposits, were tectonically emplaced into the dinaridic segment, which had been previously over thrust on them (korbar, 2009; korbar et al., 2010). in the sw, these carbonate units are in reverse contact or are overthrust over intensely deformed, predominantly clastic fl ysch deposits of the middle and upper eocene, which comprise the foothills of mt. biokovo. in several places, gently inclined fl ysch slopes are covered by tens of metres of deluvial and proluvial quaternary deposits. recent debris is frequently found below the steep carbonate slop es. the carbonate deposits of the mt. biokovo massif are intensely tectonically fragmented and karstifi ed, and in hydrogeological terms they form a permeable environment in which a deep karst aquifer has developed (fig. 3). the high karst plateau is dominated by numerous deep dolines, which often contain karst pits. several hundred pits have been infigure 1: typical hydrograph characteristics of a spring draining a) a fi ssured aquifer and b) a karstic (conduit) aquifer (q – discharge, p – rainfall, t – time, dt – time diff erence between rainfall and hydrograph peak; modifi ed from bonacci, 1993). kuhta et al.: hydrodynamic characteristics of mt. biokovo foothill springs in croatia geologia croatica 43 figure 2: regional catch ments and locations of the investi gated springs. figure 3: hydrogeological map of the study area (geological background according to marinčić et al., 1977, partly modifi ed). geologia croatica 65/1geologia croatica 44 vestigated through speleological activities on mt. biokovo. ten of these pits were deeper than 250 m, and four exceeded a depth of 500 m. the deepest pit of mt. biokovo is the amfora pit, which has been investigated to a depth of 788 m (bakšić & jalžić, 2001; bakšić & lacković, 2002). in hydrogeological terms, deep pits are a signifi cant indicator of karstifi cation of the vadose zone and a deep groundwater table. the lowest absolute elevation of approximately 790 m a.s.l. is reached in the vilimova jama pit. the fl ysch deposits that comprise the sw foothills of the carbonate massif of mt. biokovo are lithologically heterogeneous. however, due to the dominance of marls, this sediment series, when considered in its entirety, is impermeable to water. in the study area, the fl ysch outcrops appear to extend to a distance of 3 km from the coastline (fig. 3), and in places reach an altitude of 500 m. considering their structural position and their nearly uninterrupted stretch along the coastline and far beyond the study area, the fl ysch deposits form a complete hydrogeological barrier to groundwater movement from the carbonate hinterland toward the sea. thus, they have a signifi cant impact on the regional hydrogeology. according to previous regional hydrogeological studies (bojanić, 1980)1, groundwater from the mt. biokovo massif and a portion of its spacious karstic hinterland drains primarily through strong submarine springs: dupci nw of brela, and klokun near drašnice (fig. 2). they develop in locations where fl ysch and carbonate rocks come into contact below sea level. the springs function as the primary groundwater drains for the greater regional area, which explains the discharge values during rainfall periods of up to several dozen m3/s. the dupci is considered to be one of the strongest submarine springs of the adriatic. in addition to these submarine springs, several permanent springs with lower discharge values, some of which are captured for use in the public water supply system, are located along the area of tectonic contact between permeable carbonate rocks and impermeable fl ysch. this research focused on the hydrogeological characteristics of four captured springs located at the foot of steep slopes in the central and se parts of the mt. biokovo massif between makarska and drašnice. the recharge of these springs is unrelated to infl ows from the regional hinterland. they are recharged from the carbonate deposits of the mt. biokovo massif, and they have their own recharge areas in the sw, marginal parts of the regional catchments of the dupci (makarski vrutak and orašje) and klokun (podgorski vrutak and izbitac) submarine springs. this fact was confi rmed by tracing from the jama male marije pit in the lađene area of mt. biokovo, which proved the groundwater connection with the orašje and grebice springs (fig. 3). the makarski vrutak spring is captured by a 10-m long water intake gallery located at 160 m a.s.l. the gallery was built in partly consolidated breccia debris, although it can be assumed that there are fl ysch deposits (e2,3) in the bedrock. the nearest outcrops of carbonate rocks from the upper cretaceous (k2 3) and palaeogene (pg) ages form the structural unit of the kotišina-tilovica trough, located approximately 100 m north of the water intake. the primary source is probably located in the tectonic contact zone between the carbonate aquifer of mt. biokovo and the fl ysch, which is covered by recent debris, as indicated by a temporary spring in the gully above the water intake. the orašje spring is located at the foot of mt. biokovo’s steep slopes, at an altitude of approximately 465 m a.s.l. groundwater is extracted by two small intake galleries 35 m apart and then transferred by pipelines to a nearby collection chamber. although the intake is in an area composed of fl ysch deposits located approximately 160 m away from its fault contact with the carbonate rocks of mt. biokovo, and the groundwater infl ow route is unknown, (draining through the debris or the more permeable sequences within the fl ysch), it is indisputable that the springs derive recharge from a karstic carbonate aquifer in the mt. biokovo massif, as confi rmed by the aforementioned tracing study. the podgorski vrutak spring is captured by a 44-m long water intake gallery at 384 m a.s.l. although the bedrock is not visible in the water intake area due to the quaternary cover, it can be assumed that the abstraction site is located where the fl ysch and palaeogene carbonate deposits come into contact. a large portion of the hinterland of the abstraction site, which reaches the steep slopes of jurassic rocks at an approximate altitude of 700 m a.s.l., is also covered with thick quaternary deposits, and so the geological situation is not fully understood. based on available data for the area upstream of the abstraction site, there appear to be no fl ysch deposits or interruptions in the continuity of the karstic aquifer. the izbitac spring is captured by a 23-m long water intake gallery located at 20 m a.s.l. the gallery was built along the tectonic contact between the eocene fl ysch deposits (e2,3) and the palaeogene carbonate deposits (pg). between the palaeogene carbonate deposits and the carbonate hinterland, (composed of the jurassic and cretaceous carbonate deposits), where the majority of the spring recharge area is located, there is an upper layer of fl ysch deposits. although tectonically reduced and pinching out to the nw, these layers seem to signifi cantly infl uence the hydrodynamic characteristics of the izbitac spring. 3. spring measurements and data analysis measurements of water level and temperature were recorded for the makarski vrutak, orašje, podgorski vrutak and izbitac springs (using hobo water level loggers, onset computers, usa). in addition to these springs, in the sw foothills of central mt. biokovo, the grebice spring 1 bojanić, l. (1980): hidrogeološka studija područja aržano-brela-metković [hydrogeological study of aržano-brela-metković area]. unpubl. report, croatian geological survey, zagreb, 75 p. kuhta et al.: hydrodynamic characteristics of mt. biokovo foothill springs in croatia geologia croatica 45 (fig. 3) is captured for use in the public water supply system; however, due to the technical characteristics of the water intake structure, it was not possible to establish continuous water level monitoring at this location. 3.1. spring measurements measurements were taken by installing square or standard triangular weirs in the water collection chamber outlets. upstream of the weirs, water level and temperature data loggers were installed and programmed to take hourly measurements. subsequent processing with appropriate mathematical equations, converted the measured level data into spring discharge fi gures. the monitoring period lasted from 25 november 2007 until 17 december 2008. direct volumetric measurements were also occasionally made during this period. despite the millimetre accuracy of the measurement devices, the data logger results had certain defi ciencies due to the inability to fulfi l all necessary parameters, including the width and characteristics of the supply canal and the ratio between the weir height and the upstream water depth, at the weir installation sites. these defi ciencies were mostly overcome by correcting the parameters in the applied mathematical formulae for square (kindsvater & carter, 1959), and triangle weirs (rantz et al., 1982). for some springs (especially the orašje spring), it was not possible to fully calm the water surface upstream of the weir, which caused disturbance (noise) in the results. 3.2. analysis of hydrograph recessions methods for analysing the hydrograph recession of individual fl ood pulses were initially used primarily for discharge forecasts in the case of long dry periods, and to determine available groundwater supplies in aquifers (boussinesq, 1877, 1904; maillet, 1905). afterwards, karst hydrogeology specifi c methods for recession analysis were developed (drogue, 1972; mangin, 1975; atkinson, 1977; milanović, 1981; bonacci, 1987, 1993). these methods are used to determine the characteristics of hydraulically contrasting aquifer volumes, (highly permeable conduit networks and low permeability rock masses with fi ssure porosity), as well as to characterise and classify karst aquifers based on quantitative values. in this study, the longest available hydrograph recessions for the monitored springs were analysed. hydrograph recession in base-fl ow conditions is described with maillet’s exponential equation (maillet, 1905), which is probably the most frequent recession equation used in the literature (dewandel et al., 2003): qt=q0e–αt (1) where qt is the yield (l/s) in time t, q0 is the yield (l/s) at the beginning of a recession segment (in time t = t0), t is the time (day) from the beginning of recession and a is the basefl ow recession coeffi cient (1/day), which depends on an aquifer’s characteristics. the total hydrograph recession can be described by applying an exponential equation with one recession coeffi cient only when fast-fl ow spring components are absent. to describe the recession of typical karst springs with marked fastfl ow and base-fl ow components, several different recession coeffi cients are sometimes used (bonacci, 1993). the recession coeffi cient is gradually decreased in several steps. the value of the highest recession coeffi cient at the beginning of the recession diagram is attributed to the drainage characteristics of the aquifer system’s conduit network during fast-fl ow conditions, whereas the lower recession coeffi cient, which ends the recession diagram, is attributed to the drainage characteristics of low permeability volumes within a karst aquifer. however, this interpretation is not completely correct due to signifi cant variations in the temporal and spatial distribution of infi ltrated rainfall, which impact the hygrograph’s shape during fast-fl ow conditions (grasso & jeannin, 1994). this phenomenon explains why there are signifi cant differences in the characteristics of hydrograph recession during fast-fl ow conditions for individual fl ood pulses and why these hydrographs cannot be used to unambiguously interpret the conduit network characterises of an aquifer. thus, only the recession components for base-fl ow conditions were isolated and processed in this study. by integrating maillet’s equation, the dynamic volume v, which is the groundwater volume at the beginning of the recession period (in time t0) that is stored in the low permeability medium of an aquifer above spring level, can be determined: (2) where the constant c depends on the discharge and the recession coeffi cient units. 3.3. analysis of the spring hydrograph using autocorrelation and cross-correlation functions time series analyses in karst hydrogeology are used to determine karst system characteristics, to investigate the relationships between spring discharge and rainfall and between discharge, to continuously measure physico-chemical parameters and to assess the interdependence of discharge in several springs (mangin, 1984; padilla & pulidobosch, 1995; larocque et al. 1998; panagopulous & lambrakis, 2006; kovačič, 2010). univariate methods are used to analyse the characteristics and structure of individual time series, while bivariate methods are used to analyse the connection between the input and output time series (box & jenkins, 1974). in this study, mean daily discharge series were analysed with the autocorrelation function, while the connection between discharge and rainfall was analysed with the cross-correlation function. the autocorrelation function defi nes the linear dependence of successive data values within a time series, depending on their time lag. a time series is compared with itself, geologia croatica 65/1geologia croatica 46 with a discrete increase of time lag, and the autocorrelation coeffi cient r(k) is calculated for individual time lags k with the following equation: (3) (4) where xi = (x1,…xi,…xn) is a time series of n data points for which m autocorrelation coeffi cients rk = (r0,…rk,…rm) are calculated. the value of m should not exceed n/2 (box & jenkins, 1974) or n/3 (mangin, 1984). a graphical presentation of rk values for individual time lags refl ects the character, karstifi cation intensity and retention capacities of an aquifer. mangin (1984) terms the time necessary for rk to fall below 0.2 the „memory effect“ which expresses the duration of the system’s response to an input impulse. a longer memory effect indicates a less developed karst conduit network and a higher retention capability of the karst system, while a short-term effect refl ects the system’s low retention capability, with a dense, connected conduit network. the cross-correlation function defi nes the linear dependence of output yt and input xt time series, depending on their time lags. the output yt and input xt time series are mutually compared, with a discrete increase of the time lag, and the cross-correlation coeffi cient rxy(k) is calculated for individual time lags k with the following equation: , (5) where: , (6) and σx and σy are the standard deviations of the input and output series, respectively. if the input series is random, then the cross-correlation function rxy(k) presents the system response to the input impulse. because rainfall can mostly be considered as a random signal, the cross-correlation function of the rainfall and discharge presents a unit hydrograph. in this study, daily rainfall data from a gauge in makarska were used. these data represent rainfall at the foot of mt. biokovo. although events in the higher parts of the massif are more relevant for aquifer recharge, no daily rainfall gauges have been installed in the higher parts of the massif. 4. results and discussion spring yield and water temperature data were used to determine the hydrodynamic characteristics of the makarski vrutak, orašje, podgorski vrutak and izbitac springs. as late summer and early autumn during the monitoring period were dry, exceptionally low water levels and representative values of minimum yield were observed. conversely, a wet period at the end of 2008 resulted in exceptionally high water levels, so relevant maximum yields were also recorded. the spring hydrographs and thermographs (fig. 4) were created using mean daily values of yield and water temperature during the monitoring period. the basic statistical data on discharge for the investigated springs are shown in table 1. due to technical conditions at the water intake of the makarski vrutak spring, the installed weir could not reliably measure discharges greater than 200 l/s, which was probably refl ected in the slightly higher occurrence of errors in the maximum yield calculations and the shape of the hydrograph peaks. the more pronounced yield fl uctuations in the hydrograph for the orašje spring were caused by an unsettled water surface in the collection basin. the hydrographs (fig. 4) exhibit the different hydrodynamic characteristics of the investigated springs. considering the minimum to maximum yield ratios (table 1), the makarski vrutak spring has a very high ratio, typical of karstic aquifers. the ratios are signifi cantly lower for the podgorski vrutak and the orašje springs and very low for the izbitac spring. the hydrograph of the makarski vrutak spring shows abrupt fl ow variations, with a pronounced transition from the fast-fl ow to the base-fl ow regime (figs. 4a and 5a). recession analysis was conducted for the longest recession period in the monitoring period, which lasted from the middle of june to the end of october 2008, a total of 142 days. after the fi rst 40 days of the recession period, the fl ow recession assumed an exponential form with a constant recession coeffi cient (fig. 5a). the transition to slow exponential recession (i.e., to base-fl ow recession) occurred at a low discharge rate (12 l/s), which was considerably lower than the spring’s median and mean discharges (table 1). this result indicates that the discharge of the makarski vrutak spring is in the fast-fl ow regime for most of the year. the pronounced discharge fl uctuations in the fast-fl ow regime result from both the rapid infi ltration of precipitation in the epikarst and a well developed system of drainage conduits, which effectively convey infi ltrated water to the spring. a fast throughput, with an accompanying low residence time in the system, results in the spring’s high vulnerability to contamination. a relatively low recession coeffi cient during the base-fl ow regime refl ects the high retention capability of low permeability volumes in the aquifer, although their contribution to the total spring discharge is minor. consequently, the spring’s dynamic volume is lower than those of the podgorski vrutak and izbitac springs (table 2), despite its higher mean and median discharges (table 1). the orašje spring hydrograph is characterised by a clear distinction between the fast-fl ow and base-fl ow regimes and a less dominant fast-fl ow component in the total spring discharge, compared to the makarski vrutak spring (figs. 4b and 5b). the analysed recession period lasted for 140 days, of which the fi rst 23 were in the fast-fl ow regime. the basefl ow recession coeffi cient was the lowest of all investigated springs, but was similar to that of the izbitac spring. despite a low recession coeffi cient, the spring system’s dynamic volkuhta et al.: hydrodynamic characteristics of mt. biokovo foothill springs in croatia geologia croatica 47 ume was also the smallest (table 2) as a consequence of its lowest mean and median discharges (table 1). the difference between the fast-fl ow and base-fl ow components of the podgorski vrutak spring hydrograph was much less pronounced than those of the makarski vrutak and orašje springs (figs. 4c and 5c). the base-fl ow was a dominant component of the spring’s total discharge. the hydrograph’s less pronounced changes in the fast-fl ow regime figure 4: daily rainfall in makarska and temperature and discharge values of a) the makarski vrutak spring, b) the orašje spring, c) the podgorski vrutak spring and d) the izbitac spring. table 1: basic statistics for daily discharge of the springs during the monitoring period (25 november 2007 – 17 december 2008). parameter location makarski vrutak orašje podgorski vrutak izbitac qmin (l/s) 3.7 1.3 3.7 4.8 qmax (l/s) 448.2 44.9 73.7 20.9 qmean (l/s) 112.6 9.9 28.9 12.6 qstdev (l/s) 129.2 9.0 17.2 4.9 qmed (l/s) 54.4 6.0 28.9 12.9 qmin : qmean : qmax 0.03 : 1.00 : 3.98 0.13 : 1.00 : 4.54 0.13 : 1.00 : 2.55 0.38 : 1.00 : 1.66 geologia croatica 65/1geologia croatica 48 could be a result of the lower maximum draining capacity of the system’s conduit network or the signifi cant sediment layer that covers the karst and retards infi ltration. however, the highest base-fl ow recession coeffi cient suggests the existence of a dense conduit network. because of the fast-fl ow to base-fl ow transition at a relatively high discharge (approximately the magnitude of the mean and median annual discharges, table 1, fig. 5c), the system has a proportionally high dynamic volume (table 2). the characteristics of the izbitac spring hydrograph are different from those of the other springs. the fast-fl ow discharge component is completely absent, and the hydrograph recession can be described with the same exponential relationship from the beginning of the recession period (figs. 4d and 5d). this, in combination with a low recession coeffi cient, results in the system’s highest dynamic volume (table 2). the lack of a fast-fl ow component suggests the absence of a developed karstic conduit network in the spring catchment. given the lithological composition of the spring’s surrounding area (fig. 3), the appearance of fl ysch rocks in the nearby hinterland could also retard the discharge dynamics. occasional, slight increases in the chloride contents recorded for this spring indicate bathyphreatic recharge conditions, possibly through non-karstifi ed carbonate rocks below the flysch deposits. a good retention capability and longer groundwater residence times make the izbitac spring the most valuable for purposes of water supply. the time series analysis utilises daily discharge values of the springs and daily rainfall values measured in makarska. the uniform decline of autocorrelation function values for the izbitac spring discharge series confi rms the presence of only one base-fl ow component, while the presence of both fast-fl ow and base-fl ow components is clearly marked by a transition from the steep to the gentle slope in the shape of figure 5: hydrograph recession characteristics for a) the makarski vrutak spring, a) the orašje spring, c) the podgorski vrutak spring and d) the izbitac spring. table 2: base-fl ow recession parameters (α – recession coeffi cient; q0 – base-fl ow discharge at the beginning of recession; v – dynamic aquifer volume). parameter location makarski vrutak orašje podgorski vrutak izbitac α (day-1) 0.0111 0.0083 0.0173 0.0085 q0 (l/s) 16 7 28 20 v (m3) 12.5·104 7.3·104 14.0·104 20.3·104 kuhta et al.: hydrodynamic characteristics of mt. biokovo foothill springs in croatia geologia croatica 49 the other springs’ functions (fig. 6a). consequently, the izbitac spring hydrograph shows the longest memory effect (fig. 6a, table 3). the makarski vrutak spring’s autocorrelation function has typically, a two component shape, with a steep slope for the fi rst 25 days and an almost horizontal slope for the next 55 days. because of fast-fl ow dominance in the makarski vrutak discharge dynamics, the transition to an almost horizontal function shape occurs at low autocorrelation values below 0.2 (fig 6a), resulting in a short memory effect. the orašje spring’s autocorrelation function shows similar characteristics to that of the makarski vrutak spring, with an even lower memory effect (fig 6a, table 3). low memory effect and zero autocorrelation values for the time lags of 24 to 33 days on these springs are largely caused by irregularities in the orašje discharge measurement data, which is especially pronounced in the low fl ow (i.e., baseflow) regime (fig. 4). the podgorski vrutak function presents an intermediate case between the izbitac and makarski vrutak functions, with two distinct fl ow components and a less dominant and more inert fast-fl ow component, compared to the makarski vrutak function (fig 6a). the cross-correlation functions show the most rapid response and the strongest dependence on rainfall for the oraš je spring’s discharge series (fig. 6b, table 3). the makarski vrutak spring’s discharge series had a slightly lower value and a longer time lag of maximum cross-correlation coeffi cient (table 3). the general shapes of the functions for both springs are similar, with a rapid fall of values for the fi rst 15 or 16 days, refl ecting the spring’s fast-fl ow response. the low function values then slowly and irregularly approach zero until a time lag of approximately 45 days is reached. the low values following the initial rapid fall of the functions indicate the dominance of the fast-fl ow response, whereas the approach to zero marks the total duration of the system response. the cross-correlation function of the pod gorski vrutak spring discharge and rainfall shows a longer duration of the fast-fl ow regime (23 days), a lower maximum correlation coeffi cient and a signifi cantly longer time lag (fig. 6b, table 3). a long time lag of the system response implies a delay of rainfall infi ltration and slower transport through the system, which could be caused by the presence of a sediment karst cover or a less developed conduit network. again, the function shows a more regular shape and higher coeffi cients after the end of the fast-fl ow regime, which is representative of the podgorski vrutak system with its less pronounced difference between the fast-fl ow and base-fl ow responses. the izbitac spring cross-correlation function shows no fast-fl ow response and a generally low dependence on daily rainfall, with maximum correlation values for time lags of more than 50 days (fig. 6b). groundwater temperature data indicate the varying thermodynamic characteristics of the springs’ aquifer systems (fig. 4). the makarski vrutak spring had the most pronounced temperature fl uctuations in relation to discharge dynamics. the total range of the measured temperatures fell within the range 13.6 to 14.1 °c. flood pulses were followed by temperature drops (fig. 4a). during november, water waves fi rst occurred after a long recession period, and temperature drops were preceded by small increases of short duration. delayed temperature drops in relation to the start of yield increases during water waves were heterogeneous and lasted, on average, 1 to 2 days. the delays were longer figure 6: a) autocorrelation functions of the springs’ daily discharge series and b) cross-correlation functions of the springs’ daily discharge series and daily rainfall series. table 3: time series analysis parameters: system memory eff ect, maximum discharge/rainfall cross-correlation coeffi cient and time lag for maximum cross-correlation coeffi cient. parameter location makarski vrutak orašje podgorski vrutak izbitac memory eff ect 23 17 60 70 crosscorrelation coeffi cient 0.35 0.4 0.27 0.13 time lag 1.5 1 10 50 geologia croatica 65/1geologia croatica 50 following longer hydrograph recession periods and shorter during wet periods. along with sudden temperature changes related to changes in discharge, seasonal fl uctuations are also evident in the spring, with a maximum temperature recorded at the time of low yields in september and the beginning of november. such thermodynamic characteristics indicate the fast transport of water through the system by well-developed conduits. temperature increases that precede drops are probably related to the mobilisation of the water contained in low permeability fi ssures due to rapid pressure increases caused by rainfall infi ltration. an alternative explanation of antecedent temperature increases is the activation of deep conduit fl ow as the result of an increase in the hydraulic gradient within the system. the temperature of the orašje spring occasionally chang ed, mostly by dropping, in relation to yield changes, although these changes were small and near the resolution limit of the data loggers (fig. 4b). as with the makarski vrutak spring, seasonal fl uctuations were evident, with maximum temperatures observed during the summer recession, in the period from july to the end of september. the total range of measured temperatures in this spring was between 12.7 to 13.0 °c, with an average of 12.85 °c. the podgorski vrutak and izbitac springs are characterised by different, although relatively homogenous water temperatures during the entire year (figs. 4c and 4d). the temperature fl uctuations in the podgorski vrutak spring ranged from 12.1 to 12.3 °c, while those in the izbitac spring ranged from 14.9 to 15.0 °c. such small changes are within the resolution limits of the instruments and reveal the thermal stability of the recharge system. the stability of the podgorski vrutak system could be a consequence of better heat exchange between rocks and water in conduits with smaller radii, while for the izbitac spring, the stability is probably the result of the absence of karst conduits in the nearby hinterland. the minimum water temperature values in the podgorski vrutak spring were obtained during two short temperature drops in january and march. these drops were not temporally coordinated with yield increases; rather, they occurred during shorter winter recession periods. the mean annual groundwater temperatures in the observed springs ranged from 12.2 to 15.0°c, whereas the mean annual temperatures in the mt. biokovo high karst plateau were 6–7 °c. such temperature differences indicate that the majority of the investigated springs’ local catchments are located in the marginal sw parts of the massif, near the steep slopes along contact between the fl ysch and carbonate deposits. water from the major part of the plateau area predominantly drains toward the main discharge areas of submarine springs dupci and klokun. the cretaceous and palaeogene deep basinal deposits (limestones and breccias) on the nw slopes of the mt. biokovo massif, which according to recent geological investigations are considered to be a separate tectono-stratigraphic unit (kotišina-tilovica trough), comprise signifi cant hinterland sections of the makarski vrutak and podgorski vrutak springs. these deposits haven’t been previously hydrogeologically investigated in detail. according to the results of this study, it is signifi cant that in terms of the hydrodynamic characteristics of the springs, they have characteristics of permeable karstic rocks, similar to the platform carbonates of the remaining parts of mt. biokovo (high karst, dinaridic segment). 5. conclusions hydrograph analyses for the makarski vrutak, orašje, podgorski vrutak and izbitac springs in the makarska coast area indicate the different hydrogeological characteristics of the aquifers in the catchment areas of the springs. the makarski vrutak and orašje springs are typical karst springs. the podgorski vrutak recession analysis indicates a dense conduit network in the hinterland, but also its lower maximum draining capacity or the signifi cant sediment layer that covers the karst and retards infi ltration. the kotišina deposits in the hinterland of makarski vrutak and podgorski vrutak springs have not been previously hydrogeologically analysed, and are assessed to have characteristics of permeable karstic rocks, similar to the platform carbonates of the remaining parts of mt. biokovo. the analysis results for izbitac indicate that it is not a typical karst spring. the geological settings of the spring’s hinterland (fl ysch deposits) could be the cause of the spring’s dynamics. the results of temperature data analyses additionally confi rm the determined differences in hydrogeological conditions in the recharge areas of the investigated springs. all investigated springs, with the exception of the izbitac spring, are extremely sensitive to surface pollution. however, due to unfavourable topographic conditions that have prevented urbanisation and the fact that the catchment areas of these springs are located within the „biokovo“ nature park, there are virtually no anthropogenic impacts on the majority of the sanitary protection zones. thus, the risk of groundwater pollution can be considered to be low. the specifi c hydrodynamic characteristics of the izbitac spring indicate a lower sensitivity to pollution in the context of groundwater fl ow velocity and residence time. however, the atypical hydrodynamic behaviour is probably a result of the delaying effect of fl ysch deposits in the spring’s immediate hinterland, while the aquifer is karstic and is susceptible to pollution. acknowledgement the paper represents part of a hydrogeological investigation within the project entitled the „basic hydrogeological map of the republic of croatia” (project no. 181-1811096-3165) which is fi nanced by the ministry of science, education and sports. the authors wish to express their gratitude to the makarska water utility company for cooperation during fi eld explorations, nico goldscheider (karlsruhe institute of technology) and an anonymous reviewer for their constructive comments which substantially improved the submitted manuscript and david drew (trinity college dublin) for his linguistic help and useful comments. kuhta et al.: hydrodynamic characteristics of mt. biokovo foothill springs in croatia geologia croatica 51 references atkinson, t.c. (1977): diffuse fl ow and conduit fl ow in limestone terrain in mendip hills, somerset (great britain).– j. hydrol., 35, 93–100. doi:10.1016/0022-1694(77)90079-8 bakšić, d. & jalžić, b. (2001): jama amfora [the amfora pit – in croatian].– speleo’zin, 14, 7–9. bakšić, d. & lacković, d. (2002): jama amfora, –614 m – najdublja jama biokova [the amfora pit, –614 m – the deepest pit of mt. biokovo – in croatian].– velebiten, 36, 16–22. bonacci, o. (1987): karst hydrology.– springer-verlag, berlin, 173 p. bonacci, o. (1993): karst springs hydrographs as indicators of karst aquifers.– hydrological science journal, 38/1–2, 51–62. boussinesq, j. (1877): essai sur la théorie des eaux courantes do mouvement nonpermanent des eaux souterraines.– acad. sci. inst. fr., 23, 252–260. boussinesq, j. (1904): recherches théoriques sur l’écoulement des nappes d’eau infi ltrées dans le sol et sur le débit des sources.– j. math. pure appl., 10, 5–78. box, g.e.p. & jenkins, g.m. (1974): time series analysis: forecasting and control.– holden day, san francisco, 575 p. chorowicz, j. (1975): le devenir de la zone de budva vers le nordouest de la yougoslavie.– bulletin de la societe geologique de france, 7/17, 699–709. dewandel, b., lachassagne, p., bakalowicz, m., weng, ph. & al-malki, a. (2003): evaluation of aquifer thickness by analysing recession hydrographs. application to the oman ophiolite hard-rock aquifer.– j. hydrol., 274, 248–269. doi: 10.1016/s00221694(02)00418-3 drogue, c. (1972): analyse statistique des hydrogrammes de decrues des sources karstiques.– j. hydrol., 15, 49–68. doi:10.1016/00221694(72)90075-3 gajić-čapka, m., perčec tadić, m. & patarčić, m. (2003): digitalna godišnja oborinska karta hrvatske [digital annual precipitation map of croatia – in croatian].– hrvatski meteorološki časopis, 38, 21–33. goldscheider, n., drew, d. & worthington, s. (2007): introduction.– in: goldscheider, n. & drew, d. (eds.): methods in karst hydrogeology: iah: international contributions to hydrogeology, 26, taylor and francis, 1–8. grandić, s. (1974): neke naftnogeološke karatkteristike naslaga vanj skih dinarida [some regional petroleum geological characteristics of the external dinarides deposits – in croatian].– nafta, 25/3, 111–120. grasso, d.a. & jeannin, p.y. (1994): etude critique des méthodes d’analyse de la réponse globale des systèmes karstiques. application au site de bure (ju, suisse).– bulletin d’hydrogéologie de l’université de neuchâtel, 13, 87–113. jelaska, v., benček, đ., cvetko tešović, b., čosović, v., gušić, i., ištuk, ž. & matičec, d. (2003): platform dynamics during the late cretaceous and early paleogene – external dinarides, dalmatia.– in: vlahović, i. & tišljar, j. (eds.): evaluation of depositional environments from the paleozoic to the quaternary in the karst dinarides and pannomian basin, 22nd ias meeting of sedimentology, opatija – september 17–19, 2003, field trip guidebook, 101–107, zagreb. kindsvater, c.e. & carter, r.w. (1959): discharge characteristics of rectangular thin-plate weirs.– transections. american society of civil engineers, 24/3001. korbar, t. (2009): orogenic evaluation of the external dinarides in the ne adriatic region: a model constrained by tectonostratigraphy of upper cretaceous to paleogene carbonates.– earth-science reviews, 96/4, 296–312. doi: 10.1016/j.earscirev.2009.07.004 korbar, t., fuček, l., grgasović, t., palenik, d., novak, v., koch, g., blagus, z., huđber, k. & hodak, t. (2010): kompleksna geološka struktura zapadnog biokova na trasi tunela sv. ilija [complex geological structure of western biokovo mt. on the route of sv. ilija tunnel – in croatian].– in: horvat, m. (ed.): 4th croatian geological congress, šibenik – october 14–15, 2010, abstracts book cd, 392–393, zagreb. kovačič, g. (2010): hydrogeological study of the malenščica karst spring (sw slovenia) by means of a time series analysis.– acta carsologica, 39/2, 201–215. larocque, m., mangin, a., razack, m. & banton, o. (1998): contribution of correlation and spectral analyses to the regional study of a large karst aquifer (charente, france).– j. hydrol., 205, 217–231. doi:10.1016/s0022-1694(97)00155-8 maillet, e. (1905): essais d’hydraulique souterraine et fl uviale.– librairie sci. hermann paris, 218 p. mangin, a. (1975): contribution á l`étude hydrodynamique des aquifères karstiques.– phd these, université de dijon, 124 p. mangin, a. (1984): pour une meilleure connaissance des systemes hydrologiques a partir des analyses correlatoire et spectrale.– j. hydrol., 67, 25–43. doi:10.1016/0022-1694(84)90230-0 marinčić, s., magaš, n., majcen, ž. & benček, đ. (1977): osnovna geološka karta sfrj 1:100000, list ploče k 33–35 [basic geological map of sfry 1:100000, omiš sheet – in croatian].– inst. geol. istraž. zagreb (1967–1971). savezni geol. zavod, beograd. milanović, p. (1981): karst hydrogeology.– water resources publication, colorado, 434 p. padilla, a., pulido-bosch, a. & mangin, a. (1994): relative importance of basefl ow and quickfl ow from hydrographs of karst spring.– ground water, 32/2, 267–277. padilla, a. & pulido-bosch, a. (1995): study of hydrographs of karstic aquifers by means of correlation and cross-spectral analysis.– j. hydrol., 168, 73–89. doi: 10.1016/0022-1694(94)02648-u panagopoulos, g. & lambrakis, n. (2006): the contribution of time series analysis to the study of the hydrodynamic characteristics of the karst systems: application on two typical karst aquifers of greece (trifi lia, almyros crete).– j. hydrol., 329, 368–376. doi: 10.1016/j.jhydrol.2006.02.023 rantz, s.e. et al. (1982): measurement and computation of streamfl ow.– volume 1: measurement of stage and discharge. u.s. geological survey water supply paper no. 2175. schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine–carpathian–dinaridic orogenic system: correlation and evolution of tectonic units.– swiss j. geosci., 101, 139–183. doi: 10.1007/s00015-008-1247-3 tišljar, j., vlahović. i., velić, i. & sokač, b. (2002): carbonate platform megafacies of the jurassic and cretaceous deposits of the karst dinarides.– geol. croat., 55/2, 139–170. velić, i., vlahović, i. & matičec, d. (2002): depositional sequences and palaeogeography of the adriatic carbonate platform.– mem. soc. geol. ital., 57, 141–151. williams, p.w. (1983): the role of the subcutaneous zone in karst hydrology.– j. hydrol., 61, 45–67. doi:10.1016/0022-1694(83) 90234-2 manuscript received july 19, 2011 revised manuscript accepted december 28, 2011 available online february 25, 2012 geologia croatica 65/1geologia croatica 52 geol. c roat . 49/2 203 209 4 figs. 2 tabs. zagreb 1996 review paf)fr hydrocarbon reserves replacement· methods and expenditures antun bauk key words: hydrocarbon reserves replacement , c las­ sification o r hydroca rbon reserves, acqui si ti on o r reserves , reserve management, development exp­ enditure, production cost, finding cost, net present value, reservoir management. abstract resu lts of ina-naflup lin's activi ty in replacement of oil and gas reserves arc comparccl lo those o f western oil com panies. the reserve replacement ral io fo r the 20-ycar period from 19751994 is approxi­ mately 90%, but il averaged only 43% in the las\ 5 years when explo­ ration results in a l ii" domestic area were poor. exploration and devel ­ opment costs, which have also been analysed, indicate u higher cos! per barrel discovcred in tile last 5-year period. acquisit ion or reserves as a method of reserve replacement is st ill unknown in croati a, but prccisely thi s met hod sho uld provide a so lution to the current s itu a­ tion. remai ning oi l reserves are 10 be found in old fields in their final development phase and only selective introduction of new technolo­ gies and eor processes, as wcll as the lowering of produclion costs, can gua rant ee their rati onal production. full in trod uct ion of the reserve management concept is a guarantee thai such ac tivity will proceed in a manner cus tomary ror western oi l companies. resu lt s achieved to date on concess ions abroad in dicatc considerably hi gher efficiency and low er oi l cos ts, justifying ollr g rowi ng orientation towards exploration of fore ign concessions. 1. introduction the primary task of every oil company is the ratio­ nal ex ploitati on of the discovered reserves of hydrocar­ bons, the most important acti vity being the replacement o r oil reserves at least equ ivalent to the quanti ties pro­ duced in a given period. oi l companies whi ch fail to replace ihe produced quantilies of oil ancl gas arc essen­ tially self· liquidating. reserves can be repjaced by severa l methods, and such activ ity is known as reserve managc ment. the most important of these mcthods is the di scovery of new reserves as a resu lt of exploration 1'0 1' o il and gas. development operations lead in g to the increase of recoverable reserves in certain phases of" ihe fi cld 's pro­ ciucli vc life are aimosl equally important. due to the fact that determinat ion of hydrocarbon reserves wi thin a ina naftaplin, 'subiceva 29. hrt (){x)() zagreb, croat ia. proceed in gs k lj ucne rijeci: obnavlj anje zaliha ugljikovodika, klasi­ fi kacija zaliha uglj ikovodika, kupnja za li ha, uprav­ ljanje za li hama , ulaganja u razradu , troskovi p ro­ izvodnje, troskovi pronalazenja, nello sadasnja vri­ jednost, upravljanje lezistima. sazctak u rael u se analiziraj u nac ini i rewlta' i aktivnost i ina-naftaplina u obnav ljanj u rezerv i nane i pi ina. t i rezultat i lisporcdc ni su s ak livnosti ma zapadn ih naftn ih tv nki . koeficijcnt obnove rczervi za d vadcsctogodi snje razdobljc 1975 -1994 je oko 90%, a prosjek pos ljcdnj ih lret godina jc 43% sa sk romnim rezulta lima 1i islraiivanju na domacem pros toru. analizirajll sc i ulaganja 1i istra7.i vanj e i razrad u. iz ccgu se moze zak ljucili da ul aganja po jcdi ni c i olkrivell ih rezc rvi takocler rastu u posljednjcm pc logodisnjem razdoblju. kupnja reze rvi kao nacin iladomjes tavanja rezervi kod nas jc il cpoz nat. a up ravo 10 bi trebao biti izlaz iz silllacije u kojoj sc sada n'll azirno. preosta tc rezerve naft e su na starim po ljima u zavrsnoj razi razrade, te sarno selekt ivna primjcna nov ih tchno logija i eor procesa kao i sn izenje troskova proi 7.vodnjc mogu os igurm i njihovo ekono­ mi cno crpljenje. potpuno uvod cnj c konccpt a uprav ljanja iciistima pretpost :lvka jc cia cc se ta aktivnost odv ijati na nacin kako jc to orga­ nizirano ii zapadnim nartnim tvrlk:!ma. dosadasnji rezullati akti vllost i na ko nces ijama u inozem stvu uk azuj u na znaino vecu c l"ikasll os1 i ni zli c ij cnll kostanja nartc. s10 opravdava svc znacajniju orijellt:tciju tvrtkc n:l isl razivanja na inozemnim konccsijama. reservoir is a complex process repeated scveral lim es dur ing the productive life or a fi e ld , the influ ence of reserve revi si on on th e tota l vol um e and quality o f reserves is significant. the rules on categorization and c lassifi cat ion of hydrocarbon rcserves in the republic of croat ia include the te rm " balance reserves". they represent the fraction o f the di scovered oi l and gas in place, wh ich can be economically produced using cx ist­ ing technology. during the long producti ve life of a field consider­ ab le tech no logica l advances in the development and producti on o f o il and gas are to be expec ted , and the econom ic conditions such as price of hyd rocarbon 's products a lso change. these two groups of facto rs have an e ffect on the rev is io n of rescrves. since rules on reserves categorization in the republic of croat ia dif­ fe r from corresponding western standards, for the pur­ poses of" this paper reserves of a, band c j category a re identi fied as : proven " deve loped and undeveloped" reserves, according to the soc ie ty o f petroleum engi204 geologia croi1(ici1 49/2 proved reserve changes reserve replacement ratio 10'toe year discoveries extensions revisions total production (1):(5) ((1)+(2»:(5) (4): (5) & sec. reeov. +/10'toe % % % (1 ) (2) (3) (4) (5) (6) (7) (8) 1975 73 8338 8411 3654 2.0 230.2 230.2 1976 4470 4470 3875 0.0 0.0 11 5.4 1977 2100 -3315 1215 4078 0.0 51.5 -29.8 1978 18550 2995 1250 22795 5194 357. 1 4 14.8 438 .9 1979 1068 1068 4122 0.0 0.0 -25 .9 75.-79. 18623 13433 1337 33393 20923 89.0 153.2 159.6 1980 500 1875 1375 4226 i 1.8 11.8 ·32.5 1981 1240 937 2 177 4524 0.0 27.4 48.1 1982 510 594 72 1176 4576 11.1 24.1 25.7 1983 385 -3106 -2721 4277 9.0 9.0 ·63.6 1984 231 1 2311 4341 53.2 53.2 53 .2 80.-84. 3706 1834 -3972 1568 21944 16.9 25.2 7.1 1985 132 132 4735 0 0.0 2.8 1986 6879 80 792 775 1 4846 142.0 143.6 159.9 1987 6897 8694 7132 22723 5200 132.6 299 .8 437 .0 1988 2611 58 2669 5038 51.8 51.8 53.0 1989 1173 1277 2450 4957 0.0 23.7 49.4 85.-89. 16387 9947 9391 35725 24776 66.1 106.3 144.2 domes\. & intern. 85.-89. 37306 25450 146.5 1990 733 -693 40 4633 0.0 15.8 0.9 1991 50s ·1071 -566 4171 0.0 12.1 ·13.6 1992 204 1558 1762 3457 0.0 5.9 51.0 1993 513 6614 7127 3890 0.0 13.2 183.2 1994 1589 ·1539 so 3510 45.3 45.3 1.4 90.-94. 1589 1955 4869 8413 19661 8.1 18.0 42.8 dotti es t. & intern . 90.-94. 3274 1955 5530 10759 20691 15.8 25.3 51.9 total 40305 27169 11625 79099 87304 46.2 77.3 90.6 total domes!. & intern. 83026 89008 93.3 table i ina-naftaplin 's replacement of proved hydrocarbon reserves for the period 1975[994. nccrs methodology (s,p.e. , 1987). the volume of reserreserves [rom already discovered fi elds or from field s yes and production of oil and gas is expressed in tons of in development. in such a manner stabil izat ion of busiequivalent oil (toe: 1000 m3 of gas = i t of oil). ness operations is achieved and the basis formed for the through the activ ity of every oil company there are new cycle of explorat ion and other activities. financial certain periods when the produced quantities cannot be inves tments in to the replacement of reserves by each of replaced by any of the described methods and in such the mentioned methods arc naturally of primary imporcases oil companies usually resort to acquis it ion of tancc. b:luk: i-iydroc:lrhon reserves replaccmcnt meillod~ nnd expendilures 205 450.0 % 400.0 ii' 350.0 0: ~ 0 300.0 ~ 250.0 c 200.0 ~ e 150.0 ~ u ~ 100.0 a. ~ 50.0 ~ > ~ 0.0 ~ ~ -50.0 0: -100.0 1975 1977 1979 1981 1983 1985 the analysis of act iv ities related to the reserves replacement on a year to year basis will not g ive re<tiis­ tic resu lts, since they can be altered by unexpected suc­ cesses or failures. instead, the resul ts and expenses for the replacement of reserves over a longer period at least 5 years shou ld be reviewed. the pape r will analyse the activi ty of 1na-naft ap lin during the pre­ ceeding 20-year period and compare it with the results of well -known western com panies. this paper is the first attempt to analyse reservoir exploration and devel­ opment results a nd expenditures in ina-na ftap lin beyond those inte nded for internal usc. the data on reserves have been taken from the so­ called book of reserves, with ap prova l of the autho­ rized comm ittee of the mini st ry of economic affairs. t he company's financial departme nt prov ided the data on exploration and development investments. 2. methods and results of reserve replacement table i and fi g. 1 show the resu it s of reserve repl acement by ina-naftapl in in the 20-year pe riod exp!. total finding spend spend expend. oil company $iboe $iboe $iboe* produced produced majors l63 4.98 3.3l us indcpend. 2.70 7.6r 2_82 8europcans 3.64 14.8 3.1 lna (r6_ 90_) 5.4 r.r9 5_34 ina (90_ 94_) 2.83 3_9l 8.63 lna (85 .-94_) 4_2l 7.04 5.8 1 lna domest. & intern. 3_ 1 4.58 4.8 90.-94 1987 --0-rrr discoveries rrr disc. + sec. recovery total rrr 1989 1991 1993 year fig. i reserve replacement ratio for i na-nafwplin domestic . [rom 1975 lo 1994. during lhis period 72% of lhe cumulative production of ina-naftaplin has been real ­ ized and reserves have increased by 44% in comparison with those reg istered a t the beginning of that period. the analysis was prepared to estab lish the reserve re pl acement ratios (rrr). this ratio is a relationship between the volum e of repl aced reserves and real ized product ion in a certa in period. the paper analyses three methods of rese rve replacement: discovery, field extens ion and introd uc ­ tion of secondary methods during the development of a field , as well as the revision of reserves upwards or downwa rds. since the data have been taken from the book of r eserves, there' s a certain lag, espec iall y between the discovery and booking of proven reserves, which in our case may range from 2 to 12 years. the average lag is 8 years for the 22 newly discovered and analysed fi e lds ( for the group of companies from table 2 that average is 5 years). during the analysed period 8 new field s have been discovered ill this period and out of the 22 new fields 18 can be class ified as oil and 4 as gas fields. the ratio of discovered reserves is 90: 10% in favour of gas and gas-condensate fi e lds. total reserve acquisit. develop. total rr_ rrr total expend. expend. expend. expl.+revis rrr $iboe $/boe** $iboe % % 3.91 3.59 7.24 68 100 3.99 l77 4.25 99 l49 3_33 l72 5.4 128 310 2al 6_16 101 l44 3.80 9. l2 32.8 42.8 2.85 7.09 72.5 99 .3 3_67 8.36 42.5 52.0 tabl e 2 reserve replaeemenj expendilllre 5-year average 1986-1990. legend: * boe discovered+rev ision: **dcvel.expend. / total reserve increased. 206 geolog ia croalica 49(2 160 ~.------.-------------------------------------------, 140 % 120 ...... ........ 100 ~------~~~--------~l-~~-.. -... -... -.. . -... -... -... ~.?-----~~, •.. ---------+~ " , .... ..... , , 80 60 40 20 ~ ./ './ ''.. / . ........ . '---'..'..-------........ _--o ~----.----'----'-----r----.----.----'-----'----.---~ 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 year ' oiscoveries --discovery + sec. recovery . acquisitions discovery + sec. recovery + revisions _____ discovery + sec. recovery fig. 2 reserve replacement ratio for major compa­ nies. replacement ratio for the 20 year period of ac tivity in the republic of croatia is 90.6%, 50% of which arc newly discovered reserves, and the remainder is the result of field extension and introduction of secondary oil recovery methods (31 %) and revision of reserves (14%). analysing the 5-year periods, the replacement of reserves was sllccessful in the periods from 1975 1979 and 19801984. in the former the resu lts can be mainly attributed to the discovery of the molve gas field and the introduction of secondary oil recovery methods at. the benicanci and zutica fie lds. in the later pe riod thc rcscrves of kalinovac, stari gradec and ivana gas and gas-condensate fields have been taken into account, together with those related to the exten­ s ion of the molve and delctovci fields, as well as the results of several successful rev isions of reserves. the average reserve replacement ratio based on exploration , which exceeds the balanced average achieved by the group or large oil companies in explo­ ration over a several -year period (pig. 2), can be attrib­ uted to three significant gas discoveries (molve, kali­ novac, ivana). th e results of the last 5-year period 1989-j994 (with rrr at 8.1 %) are disappointing, especially in vi ew of the fact lhal unrecorded but discovered reserves will not significantly change the situation. the results of the period from 19801984 arc similar, in fact the ove rall results of reserve replacement by all methods arc the lowest only 7.1 %. extens ion of reservoirs in the existing fields and the introduction of secondary methods to increase the recovery ratio is an important method for the replace­ ment of reserves. for the group of major companies (fig. 2) it amounts to approx. 20% and for ina-nafta­ plin about 31 % . it needs to be stressed that the most significant additional reserves acquired by this method have been recorded in the same period as the discover­ ies , resulting in two pronounced peaks in 1978 and 1987. since we have no major oi l fields as candidales for the introduction of secondary methods, this method cannot be expected to significant ly increase our reserves. this paper particularly focuses on the rational utilization of remaining reserves. activities involving the reinterpretation of geological models of reservoirs are ongoing and are expected to yield some positive results. the difference between the extension of reser­ voirs and revision of reserves has to be explaincd. extens ion of reservoirs results in new reserves based on the increase of reservoir volume defined after thc completion of geological, geophysical analyses and after dri lling. there is a te rm "reserves determined by bit", which arc the result of operations conducted dur­ ing field development. revision of reserves is also a continuous activity of field development which consisls of the revision of all parameters [or reserves calculation , including recovery factor prediction. revisions were carri ed out at 5 year intervals. the basis for every revision is the monitoring of field production performance and results of calcula­ tions or numerical simulation of the reservoir depletion process. revisions can be optimistic or pessimistic, the average for the 20-year period from table 1 is + 14%. pessimistic revision of reserves (-18%) is evident in one s-year period (1980-1984) and for other such peri­ ods revisions differ by +6 % to +38% in comparison with the total change of reserves. the size of change in reserves bascd on revisions also reflects company poli ­ cy, i.e. is it more or less careful in the definition of reserves. depending on the year the growth of reserves based on revision ranges from 20-50% for the group of large companies (fig. 2). results of revision are often added to the ini tial reserves of the discovered fields, as in this paper in the analys is of funds spent in exp loration activities (table 2). i3;llik: il ydrocarbon rcscrves replacemen1 . methods and expenditures results related to reserve replacement mentioned so rar refe r to the activi ty of ina-naftaplin in our national exploration area. effects or activities on concess ions abroad arc prcsented in table i. detailed data are given only for the 1990-1994 period, together with the ovcrall eltec ls for the two s-year periods when we recorded production abroad (mostly from block 3 in angola). contr ibution or our expenditure into exploration and development abroad is ev ident. the reserve replace­ ment ratio for foreign field s ror the period 1990i 994 amounted to 228% and reached 235% in the period from 19851990. 3. rational exploitation of ina­ naftaplin's remaining reserves out of the predicted recovery ratio of 36%, 30% of the discovered reserves of oil have been produced by the end of 1995. the realized recovery ratio for free gas amounts to 30% of the predicted 72%. only the cxploitation of the remaining oil reserves will be dealt with in this short analysis, since major gas fields are in the stable development phase and incorporation or new rescrvcs into production is to fojlow. based on thc current data, about 5 x 106 m3 or o il or about 25% 01" the rcmaining recoverable oil reserves have been catego rizcd as uncommercial reserves, pri­ marily in view of high production costs, particularly in ihe final phase of exploilalion. by lowering exp loilal ion costs and increas ing well productivity part of those rescrvcs could turn into commercial reserves. economic cri teria will be decisive in the introduc­ tion of new technologies applicablc to additional devel ­ opment of old reservoirs with rescrvoir pressures con­ siderab ly be low hydrostatic pressure and with hi gh water conten t. secondary methods are being appl ied in is major fie lds wit h over 80% of initial reserves, or wherc we have an efficient natural water dr ive. the greates t attention should be focused on thi s grou p of fie lds, since the remaining 27 ri elds account only for 3 x 106 t of unrecovered reserves, and only 0.6 x 106 t of rcscrves that have not already been placed inl o production. the expected rccovery rate for the fi rst group of fi elds is est imat ed at 38%, which means th at 62% of the discovered (geo logical) reserves wou ld remain in the reservoi r. according to the analyses, 22% is the so-ca lled mobile oil in those zoncs of the reser­ voir with poor. reservoir characteristics which have not been swept by water cncroachmen t. a par t of those rcserves can be ac ti vated by in-fi ll drill ing, application of intensive stimulation (hydraulic fracturing ), drill ing of" horizontal well bores in old wells (re-entry), or by horizontal drilling . thcse opcrat ions arc already in progress. the second part of remaining oil amount ing to some 40% (90 x ioii t) is the so-called immobile oil, which rema ins in pore spaces behind the water front. under our reservoir condi tions, some of this oil can be recovered by the injection of co2 into thc reservoir 207 unde r miscible cond iti ons. laboratory research and numerical simulations have indicated that some 9-24 x 106 m3 of oil cou ld be recovered from the ivan ic grad, zutica and struzec fields in thi s way . thc projects are economi ca ll y sensiti ve and only pil ot-projects in the fi eld could provide the data for business dec isions relat­ ed to the ir full-scale implementat ion. poss ibili ties previously considered by naftap lin's experls (bau k c i ai. , 1988) have only been briefly mentioned he re. other eor processes would be hard ly applicable in our condi tions. in such ambitious projects it is important to apply the reservoir management concept, which is defined as: increasing the economic vallie of oil alld r;as reservoir to the maximum by opti­ mizing recovery and production. and by reducillg expenditures a/ld production costs to the miniml/ill rates. this definition implies a continuous team e ffo rt or experts, including geophys icists, geologists, geosta tisti­ ci ans, reservoir e ngineers, production e ngineers and econom ic-ana lysts from the discove ry of the field to its abandonment. thi s concept has been applied only par­ tia lly and without cont inuity. 4, reserve replacement expenditures analys is of expenditures into the ex ploration , devel­ opment and acquisition of reservcs on global, reg ional and com pany leve l is certainly the most important ac ti vi ty in direct ing hydrocarbon reserve manage­ ment st rategy. table 2 shows the data for gro ups of western com­ panies (johns & gailey, j 992) and fo r ina-nafla­ plin for different time periods. ina-naftaplin finan ci al data were often inconsistent due to the nature of the for­ me r econom ic and political sys tem . exploration and devclopment expenditures we re ofte n burdened with irrclevant item s, while so mc expendit ures wh ich, according to current practice should have been incorpo­ rated were omitted. since the process of intensive analysis of all expen­ ditures involved in the process of exploration, develop­ ment and production of oil and gas is relat ive ly new, it is to be expected that th is pioneering work could expe­ rience some corrcct ion s. howewe r, est imat es derived on the basis of such data, in th e author's opin ion, shou ld not undc rgo major changes. table 2 li s ts the data re lated to overall spending per barrel produced, which is an indication of the intensity of spending dur­ ing certain periods. a drop in investment by ina is evi­ dent in the pe riod 1990-1994, but over a longer period inves tm ents are at par or higher th an in certain groups of western com panics. thc e ffccts of this can be seen in the last two columns. spending d uring a particular period (especially in exploration) has a greater effect on reserves in the 1'0 1lowing period than in the one when they were in vested. negative conscq ue nces of lower invest ments in the 208 7.0 6.0 5.0 "'-l 4.0 o " 3.0 l x,4.5 ""6.3 / \ \ "'x 3 .7 , , , geologia croatica 49{2 6.0 / ~ \ development -exploratcrl / \ ~ 38 37 \ x, / , 3.2 / "-·x / 'x 31 ""'x/2.6 \\ \ 2.0 2.1 2.0 1.0 0.0 1985 1986 1987 1988 1989 1990 year period from 1991-1994 (fig. 3) remain to be identi fied. spending per barrel of discovered reserves is also listed in table 2. overall exploration costs refer to discovered reserves together with revisions made during the pro­ duc tive life of a fi eld and considerably exceed the data for fore ign com panies. 11 also refers 10 development spending and particularly to the overall cos t of reserve replacement, except possibly for the period from 19861990. in business circles, the rule is that total costs or reserve replaceme nt should not exceed 1/3 of product ' s selling price, if olle is to ach ieve acceptable ret urns. 5. acquisition of reserves we have already mentioned the importance of acquisition of reservcs on the stabilisat ion of business operations. table 2 shows expenditures of foreign com­ panies for the acquisition of reserves . such activities havc not bccn prcviously recordcd in tnanaftaplin. companics arc buying (or selling) reservcs to stabi­ li ze the overall costs of reserve replacement. figure 4 shows reserve rep lacement costs by all methods and participation of reserve acquisition. we have already mentioned that initial estimates of discovcries based on exp loration are considerably upwardly revised (in ina by 6-38% and in the group of western companies by an ave rage or 40%) (fig. 2). oil compan ies which buy rcscrves on the market try to make reserve est irnates as re liabl e as possible and cxpect s ignifican t increases during deve lopment. some analyses indica te a 15 % improvement in comparison with the initial estimates. one such analysis (johns & \ \ ~ ~jj'x 1.7 \ 0.9 x 1991 x· _ _!,;!/ -1 0 . 7 1992 1993 1994 fi g. 3 exploration and dev­ elopment expenditures per doe produced in ina-naftaplin. gailey, 1992) indicates a great dispersion of acquisi­ tion estimatcs. the net present va lue (n pv) io of future production estim ated at the time of purchase and compared to the acquisi tion price, differs from the re-estimateci (npv)lo and paid price for acq uisition updated to reflect the time value of money at the time of revision of these transac­ lions. the data indicate that some companies have overes­ timated purchased acquisitions by as much as th rec times, but some can expect 2-4 timcs greater profits on thcir investments. d iscovered fields , fields in develop­ ment or those in full product ion arc be ing purchased. ina-naftaplin has made some attempts in that respect, but without success. an analysis of indicators showing effects of rescrvc replacement (fig. 1) should lead to the strategic conclu­ sion that acquisition of reserves can reliably incrcase reserves at present and provide an impetus for the new eyele of reserve management based on modern con ­ cepts which this paper tried to outline. 6. conclusion the primary task of every oil company engaged in cxp loration and production of oil and gas is to increase reserves of hydrocarbons. in the precccding 20-year per iod ina-naftaplin has , by exploration and develop­ ment activities, suecesfully replaced almost all pro­ duced quantities. it has also maintained the stabi li ty of hydrocarbon production in the process, but with a con­ siderable drop in oil production. this can mostly be attributed to the discovery of gas and gas-condensate fic lds and to the introduction or b~llk : i iydroclrooll reserves r..opl~ccl1lc!h mcthods :ll1d expellditun.:s 100 90 ~ 80 70 60 % 50 f= = [f\ ~ = 40 30 = r= / 1\ 20 10 0 j ~ / --" ,,~ -f'. f---~ " ii 'a. " r= ,. 80 70 60 50 40 10 9 $ 30 20 10 2m fig. 4 worldwide capi· 1980 198 1 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 o tal expe ndilllres ror exp lora tio n und dev­ c=j exploration & development c=j reserve acquisition _ proved acquisillon (%) elopment and proved reserve acqllisi tions. seconda ry rccovery mcthods in somc field s . the reserve replaccmcnl ratio in thc last 5 years is bclow 50%, partly caused by lo wer invcs tmcnt in ex plo­ rations, and parll y becausc ihe remaining polcnt iai o f our domes tic exploration area has 110t been able to pro­ vide ne w reserves sullic ien t to rep lacc the quantiti es produced , panicu larly where oil is co ncerned. there­ fore our rcscrve replacemcnt costs are somewhat higher than the average for wes tern com pani es. remaining reserves of oil arc mostly to bc fo und in very old rie lds and the scleclive introduction of new technologies anci eor processes could rai se their production economics. results of explorali on activ it ies abroad to date onl y st ress the necessity for its further intens ification. in the next several yea rs results wh ich wo uld stab ilize the reserves or o il and prevent funhcr drop in producti on arc unlikely. acqui sition of reserves would be a proper strategic decision at present. it wou ld employ the con­ siderab[e human potentia l of the company and prov ide an impet us for the new cycle of rese rve management based on princ iples used in modcrn western oil compa­ nics. 7. references bauk, a., cu bric, s., sar idj a, v. & gori cn ik, b. ( [988): nov i pristup razrad i lezista naft e i p[ina.· na rta , 39/1 1·12,659·672, zagreb. joh ns, e.e. & gail ey, j.d. (1992) : a rev iewal' oi l and gas reserve acquisition activity and its contri bu­ tion to company pcrf'ormancc.spe oil and and gas econom ics, finance & manage me nt confer­ ence, 28·29.4. i 992.,272·296, london. s.p. e. ( 1987): defin iti ons for oil and gas rese rves.­ jollr. pel. tech., 39/5, 577·578. 210 gcologi:1 cro:liic:149/2 geol. croat. 50/2 21s 223 3 figs. i tab. 2 pis. zagreb 1997 alveolinas from the bunic section (lika, croatia) katiea drobne i and mladen trutin' key words: alveolina, a. liislrica, a. rakoveci, palaeo­ biogeography, biostratigraphic correlation , cuisian, adriatic carbonate platform, bunit, croatia, golez, slovenia, hrgucl, herzegov ina. abstract the sunie section of palaeogene carbonates is exposed in a tec­ tonic window through the dinari c tectonic unit s in the kozjak valley in the central pari of the lib region (croatia). the lower eocene limestones in this section yielded all'colina hisfrica .i'eplel1!riollali.l' and a. rakol'(:ci. these two species characterize a particular facies of shallow waler deposits during mid dle 10 late cuisian times, as observed ul go1c1 and voz on the north-western margin of the adri ­ atic and also at li .~tica and hrgud in herzegovina. thi s is in cont rast to alveolina assemblages of the same age composed of a. lel'all/illa, peri/ocl/lilla darnlafilla. cuskillulill(/ /ii)//l"i/ica. which characterize the sha llow transgressive deposits of the coastal and insu lar region s in particular at the pican and benkovac sections. the bunic alveol ina assemb lage indicates that the limestones in the tectonic window fonned part of the sedimen tary realm represent­ ing the north -eastern margin of the ad ri atic platform. thi s also su p­ ports herak' s tectonic model by distinguishing two tectonically sup ­ erimposed carbonate platforms, the di//(/riciiii/ and the ad,.iatic/liil, separated by an interplatfonn basin called the epiad,.ia/icliill. i. introduction in centra l lika (croatia) the palaeogene strata crop out ovcr a very restricted area (fig. 1). the larges t occurrence of eocene limestone and flysch is located between buni es and canak villages, 23 km south of the plitvice lakes. the rudist limestones of the upper cre­ taccous are surrounded by tectonic contacts, for a few metres only, the original transgressive contact betwecn the rud ist limcstones and the overlying palaeogene car­ bonates has been observed by m. spari ca (polsak et ai., 1978; sparica. 1978). these outcrops of palaeogene strata ini t iated two hypothescs to exp lain their origin, either as erosional remnants of a pa laeostructural syncline, limited partly by fault s (sp aric a, 1978, p. 292. pi. i) or eocene windows belongi ng to the subjacent unit of the adriatic i i.rakovec in stit ute of palaeo nto logy zrc sazu, gosposka 13, slo-iooo ljubljana, sloven ia. 2 ina -consulting, savska 88a, hr 10000 zagreb, croatia. carbonate platform (adriaticum) covered by the dinaric carbonate platform (dinariclim) (herak, 1986). the schematical cross-section given in fig. 1 corre­ sponds to the former interpretation, in between the adriaticum and dinaricllni platforms, herak recognize an interplatform sedimentary belt, named epiadriati­ cum, extending from nw slovenia to montenegro (fig, 3 and herak, 1985, 1987, 1989, 1991 . 1993) . untill 1985 investigations were carried out within the fram e of the project entitled "palaeogene forami­ nifera of carbonate development", organized by ina­ naftaplin. researchers from zagreb and ljubljana cooperated with this and the bullies locality was includ­ ed in these studies. among the foraminifcra the alveo/i­ na species were studied in more detail than other species. selected species of the genus alveolina were used for biostratigraphic correlation of the contempora­ neous sections along the adriatic coast and for compari­ son with the buni" fauna (drobne. 1977; drobne et ai., in press). the aim of this paper is to present the nature and the probable causes of the fauni stic similarities in the alve­ olina associations from buni es and the adriatic platform. 2. the bunic section the palaeogene strata crop out over a distance of 10 km along the very narrow kozjan valley. the belt of limestone is not continuous. flysch sed iments are visi­ ble for less than i km along the road (fig. i). the bunic-kozjan section (1-9-j) with the collected samples bu-ko from 11 to 4 is located on the southwestern slope of the valley, approximately southeas t of canak viltage. the samples bu-ko 64-67 were taken from the bottom of the valley below, in front of the main secti on (fig. 2a). the base of the logged section is marked by the rud­ ist limestones of senonian age at an altitudc of 965 m. probably, there is a tectonic contact between the senon­ ian and eocene strata. the total lcngth of the outcrop­ ping section amounts approximately to 400 m, and the thickness of the al veolina-nummulitc limestone to 120 this paper was presented at the scientific meeting dedicated to the 80th anniversary of the life of professor milan herak, held on march sth, 1997 in zagreb 216 o soom 1 2 3km '-'--'-~~-~. ------'. a 1000 750 500 250 a ~~.he!,ip't"'al geological profile o soom 1 2km " , b legend 9 -f n ~ 1 :"' : '". 2~ § 3 _ ••• , 48 q 5~ k2 e3 01 6_ k1 e2.3 7 /"" e1.2 8~ fig. i location and geological map of the s!lldy area (modified after spar1ca, 1978, tab. 1), legend: 1) quaternary: 2) upper eocene/lowe! oligocene breccias: 3) middle and upper eocene marls, rarely sandstones; 4) lower eocene limestone with larger foraminifera: 5) upper cretaceous limestones, dolomites; 6) lower cretaceous and upper jurassic, on the map only lower cretaceous: 7) position of bunie sectioll (i-9-j); 8) tectonic lines; 9) transgressive contact cretaceous/palaeogcnc considered by spar lea (1978), m. the logged section ends at sample bu-ko 4 (figs. 2a, 2b) where the section is interrupted by a fault (fig. 2b). the inclination of strata varies from 30-45°, and their strike is in nne direction. the beds are in inverse position, and are partially folded. the limestone is (cetonized and cut by calcitic veins. due to the dense vegetation the success ion of [ayers can not be easily observed. beds of 30-70 em thickness prevail, ailernat ing with rare, thicker beds of 1.0-1.5 m. in the sequence packs tones to wackstones are domi­ nant. the foraminifera are poorly preserved, their shells, regenerated during life, were broken by post­ diagenetic microleclonic events (plate i). 3. alveolina from the bunic section the study of the a!veolina species is based on 8 samples from the main sequence of the bunic kozjan (1-9-j) section and on 7 samples from isolated localities (figs. 2a and 2b). the oriented sect ions of alveolin([ represent 14 species (tab. 1). this indicates a middle cuisian age in the lowe r and middle part of the section , and upper cuisian age in the uppermost beds only (fig. 2b; pi. i. ii). there are tethyan species represented by a. cremae checchia-rispoll, a. schwagcri checchia-ri­ spoli. a. aff. canavarii checchia-rispoll, a. ruetimeyeri hottinger, a. rectiangula drobne and others. they have a broad geographical distribution in the mediterranean, in both carbonate and clastic deposits (checchia-rispoli. 1905; hottinger. 1960; di scotto, 1966). the appearance of species belonging to the phylogenetic lineage of alveolino hisfrica is of particular sign ificance. they were first described in sw slovenia in the kozina, slavec and gold. sections under the specific designation: a. histri­ ca his/rica drobne and a. h. septentrionalis drob­ ne [rom the middle cuisian, as well as a. rakoveci drnilm:: & tnl1in: i\ lveol illo\s from the bunk' scclioll (lib. croati a) 217 --------------------------------------------fig. ]: a) topographicallllllp show ing the position of the bunic secl ion and isolatcd poims ( bll~ko 61 -67). b) slratigraphic co lumn of ihe blillic logged section, lilhology mid main spccies of all'co /il/(f (afle r drobne et al" in press). legend: 1) limestone; 2) micriti c limestone; 3) weakl y bedded limesionc; 4) tectonic linc: 5) isolatcd point; 6) section line. drob ne from the upper cui sian. members of th is lineage al so occur on the island of krk, on the northern yoz promontory (drobne, 1977 , 93-95,78, ill). in the eocene limestone ex tcnding rrom ci ca rija to tri ­ es te, a perfectly preservcd assemblage with a. rakoveci. was discovered at the rosandra panorama viewpoint at the slovenian -llali an border (personal data). north of the karavankemts. in the ivartnik section, the presence of a few a. ii. his/rica specimens was recorded by drob e e t al. ( 1977, tab.l , pi. i , figs. 5-7). thi s locality belongs to a particular tectonic domain (fig. 3), th e so-ca ll ed dinari calpidic complex of herak (1991). in herzegovi na, the species frolll the a. hisfrica lin­ cagc were also found in the listi ca section (personal da ta), and on mt. i-irg ud above the historica l city of stone (drobne et ai. , in press). 4. palaeogeographic distribution of species belonging to the a. his/rica lineage all occ urrences (except lvartnik, tab. i) whi ch yie ld representatives of the phylu m a. his/rica are loca­ ted within a narrow res tricted arca extending in nw-s e dinari c direc tion. t hi s area rep resent s a palaeogeo­ graphic domain interpreted as the north-easte rn margin of thc adriatic platform. north-eastwards, this margin is obscured by basinal te rrigenous sed iments along its ex tension, in nw slovenia (pays ic et a i. , 1996) as well as in herzegov ina (sliskoyic et ai. , 1978). t he adriatic platfonn constituted an isolated shoaly zone in the centra l tethy s du ring the palaeoge ne (hotti ­ nger, 1990). it was drowned at different timcs in dif­ ferent places according to the la tter's re lat ive posit ion with respect to the platform margin, and subsequently covercel by terrigeno us sediments . therefore, is thc geographically restr icted occurrence of the a. his/rica phylum due to true endem ism, or to env ironme nta l rest riction s corres ponding to a part icu lar facies belt characterizing the plat form margin? the isolated pos iti on of the palaeogene adriatic platform in the tethyan sea may be a good prerequisite for endemi sm. the occurrence of a. his/rica in lvartnik , out sid e or the adriatic domain would suggest ot her­ wise. however, the palaeogeographic pos iti on of thi s latter loca li ty remain s clear, as thc positio n or the palaeogene-eurasian contincntal margin in lile alpine realm has not been accurately reconstructed. in particll ­ lar the pos iti on of the karin thian krapp fe ld olltcrops ljcologm lroallc:l :lull golei voz bunle listiea hrgud rosandra alveolina dobrinj stolae ivartnik a. azzarofii 0 0 0 upper a. rakoveci <0> <0> <0> <0> <0> a. h. septentrionalis <0> <0> <0> <0 > <0 > a. histrica histrica <0> <0 > <0> <0> c a. fornasinii 0 0 u a. aff. canavarii 0 0 0 0 0 i a. cosinensis cosigena 0 0 0 0 0 s a. ruetimeyeri 0 0 0 0 0 i a. cremae 0 0 0 0 0 a a. distefanoi 0 0 0 0 0 0 n a. schwageri 0 0 0 a. cofatiensis 0 0 0 a. carantana 0 0 0 middle a. rectianguja 0 0 t"blc i assoc iation or alveo li n<ls, specially the spec ies or lhe phy logenetic lineage ah'eolillg his1rica, m arked <0>; ror location of scc lion!i !iee fig. 3. (w here a.. his /rica is absent van ]-iinte, 1963), in relation to tvartnik is unknown. allernatively, the adriatic area corresponding to the dis tribution of a. hisfrica ex hibits a common sedimen­ tary hi story. carbo nate sed imentation is continuou s rrom the t1 erd ian to the c ui sian and the pl atform was drowned prior to the base of the lutetian. th is charac­ terizes the platform margin in contrast to inncr parts of the platform where the marine carbonate sedimentation began laic, with the c ui sian transgression, and ended, du ring the lutetian (drobne, 1977). platform margi ns doubt lessly have habilats ot her than res tricted areas o r the in te rnal parts (hotti­ nger, 1980) and may the re fore del imi t narrow, be lt­ like areas of di stributi on for taxa of the larger forami­ nifera. the present state o/" knowledge does not permit a definite answer to these questions. however, the lin­ ear al ignment of the a. hisfrica occurrences emphas izes the close facies re lationship be tween the lis tica-hrgud and the rosandra-voz areas (fig. 3) and just ifies ad­ ding the bunie a. histrica occurrence into the linear rc­ a im. as a consequence, the bunie occurrence must be inte rpre ted as a tec tonic window, where a piece of the adria tic platform margin is expressed from beneath the overthrusted dinaric leclonic unit. s. conclusion the linear exte ns ion of the distribution of the c uis ian alveol inid species belonging to the a. histrica phy luill . between ne s lo venia and se herzegov ina corresponds to the ne margin of the adriatic platform which constituted an isolated shoaly area in the tethyan sea. the presence of a. iiistrica in this narrow belt may ei the r reflect particular environmental conditions a long the platform margin, or represent an area delimi led by endemism, or result from a contribution of bolh factors. thus, the facies relations bel ween the cuisian alveolina limestones are significant enough to justify an interpre­ tation of the bunie alveolina limestone as an intennedi ­ aiy part o f the platform marg in , hidden beneath the overthrusted dinaric unit (fig. 3) and emerging in iso­ lated points from below in a tectonic window. acknowledgement the authors wish to thank the ina-naftaplin in sti ­ tution , which, many years ago, provided the opportuni ­ ty to study the bunie section, colleagues ljubo bab ic and ]ozica zupanic for pe rmi ssion to use the data froill the listica sect ion , colleague simon pirc fo r translat ion of the text and nol least lukas hotti ­ nger for critical remarks and for the enlargement of the palaeogeographic ideas. the authors also thank both our researeh institutions zrc sazu and ina consull­ ing for support during the invest iga tion and realisa ti on of this s tudy. 6. references checchia-rispoli, g. (1905): sopra aleune alvco­ line coceniehe della sicilia. pa leontographia ll a l. , ii , 147-167, pis. 12-13_ drobnc & trut in: alvcotin:ts from the bunie sect ion (lib. cro:lli:t) • • + adriatic sea • i:l.o 5 p c o 50 100km , di scotto, c,b. ( 1966): le alveoline del gargano nord-orienlale,palaeonl. lial., 6, 65-73, pisa. drob ne, k. ( 1977): alveol ines paleogenes de la slovonic el de i' lst ric.mem. su iss. pa leonl. , 99, 132p., 21 pis. drobne, k. , pavlovec, r. & drobne, f. (1977): pal eogene larger foramin ifera from the area be lwcen mczica and slovenj gradce (n w yugo­ slavia).razprave sazu 4. razr. , 20, 88p. , 23 pis., ljubljana. drobne, k., trutin, m. & pavlovec, r. (in press): paleogene stratigraphy of the adria tic car­ bonale plalfoilti .dela opera sazu 4. razr., 34/3, ljubljana. drobne, k., vla hovic, i. , trut in, m. , pav­ lovec, r., cosovic, v., babac, d. , cimer­ man, f., lucic, d. & pavsic, j. (199 1): excur­ sion b ravni kotari, paleogene.in: vlahov1c~. i. & velic, i. (cds.): some aspecis of ihe shallow water sed imentation on the adriatic carbonate plat­ form (permian to eocene), excursion guide-book, 2nd intern. symposium on the adriat ic carbonate pial form , zadar, 53-90, 7 pis., zagreb. " a 2 19 fig. 3 geotectonic belts, aftcr her ­ a k ( 1986, 199 1 fig. 5) wit h the pos itio ns o f the sec ti ons com posed by alveo tina -num­ mu lite limcsto ne . legend : a) structural complex of the adri­ ,h ic carbonate platform (adri · allcum); e) depos it s of pelagic provenance in con nec ti o n with tile interpjatform belt (cjjiadrj­ (lli(:iiiii): d ) structura l complex of the dinaric ca rbonate pl a t­ fo rm (dil/ariwlii): da ) t he joi­ nt a rea of the dinarides and alp­ id es; s) st ruc tural co mpl ex o f the inner dinarides (su{jradil/ar­ icllm) which originated in con ­ nec tion with th e oce.u1 be lt o f the t ethys; black: ultrabas ie, ba­ s ic and associated rocks: p) pre­ alpine st ructural complexes (p i pannon ian s truc ture, p2 se r­ bo-macedon ian massif): c) car­ pathoba lka ni an be lt. a i' el ) tectonic windows within the oi· nar;cllm; 0 occurrence of a. hi.l'lrica; .1. cocval al veolinicl as­ semblages without a. his/rica, shown at the pi ca n (1 s t ria) and bcnkovac ravni kotari secti­ o ns (drob ne , 1977; drob­ ne et ai., 1991 ). herak , m. ( 1985): on ihe rehuion of aclrialic and dinaric strllc tllres.razpravc sazu 4 . razl, 26, 40 1-414, ljubljana. hera k, m. (1986): a new concepl of geoleelonies of ihe dinaridcs .acla geol. , 16, 1-42, zagreb. herak, m. (1987): the mohorovicic diseonlinuily in yugoslavia.aela geol. , 17,5-45, zagreb. herak, m. ( 1989): rela lionship belween adrialic and di naric carbonate platrorms.mem. soc. geol. it. , 40 ( 1987),289-293. herak, m. (1991 ): dinarides . mobilislie view of ihe genesis and structure.acta geo!. , 2 1, 351 j 7, zag­ reb. herak, m. ( 1993): addilional eo nsideralion on ihe epiadriat icum, outer dinarides.geo!. croatica, 46, 165168. hotti nger , l. (1960): reche rches sur ics alveoli­ nes du paleocene et de j'eocene.mcmoires sliisscs de palconlologie, 75-76, 243 p. hottinger, l. (1980) : reparlilion compa ree des grands foraminifcrcs de 1a mer rouge et de i 'ocean 220 inelien. ann. univ. ferrara (nuova serie), ser. ix, vol. suppl. 6, 1-13. hottinger, l. (1990): significance of diversity in shallow benthic foraminifcra.aui del quarto sim­ posio eli ecologia e paleoecologia delle comunita bentoniche, 35-51, torino. pay sic, j., dolenec, t. & horyat, a. (1996): kanaj-lig cretaceousffertiary boundary in flysch.­ in: drobne, k., gorican, s. & kotnik, b. (eds.): tnt.workshop "the role of im pact processes in the geological and biological evolution of planet earth", 203-209, ljubljana. polsak, a., crnko, j, simunic, an., simun1c, ai., spar1ca, m. & jurisa, m. (1978): osnovna geoloska karla sfrj i: 100.000. tumac za list bihac l33-116.inst za geol. isli·az. zagreb (1967), save­ zni gcol. zavod beograd, 51 p. sllskoyic, t., payloyec, r. & drobne, k. (1978): older paleogene in i-iercegovina. zbornik radova 9. kongr. geol. jugoslavije , 125128, saraje­ vo. sparica, m. (1978): stratigrafija, tektonika i paleo­ geografija podrucja bunic-canak u lici (hrvatska) (stratigraphy, tectonics and paleogeography of bunic-canak area in lika (croalia».geol. vjesnik, 30,281-295. van i-iinte, j.e. (1963): zur stratigraphic unci mikro­ paltiontologie del' oberkreide und des eoz~ins des krappfeldes.k~irntell jahr. geol. bullelesanstalt, sonclerbancl8, 147 p., 22 pis., wien. manuscript received april 14, 1997. revised manuscript accepted november 10, 1997. plate i alvcolina-nllmmlliitc limcstone, a. recfiangll/a drobne, a. rakoveci drobne, glomalveolina sp ., orbifolifes sp., nummufifes sp., packstone, du-ko 64/54.13. 2 packstone, baclly preserved foraminifera, bu-ko 4/5258. all enlarged xl 0, incident light ol'obnc & trutin plate i 221 ,. .' . , " : .-, ... , . ' " • : t ... 1 plate ii aiveolillo rakoveci drobne, [a , axial section, bu-ko 64/5417, upper cuisian 2 a. rakoveci drobne, r a, equatorial scction, bu-ko 64/5413, upper cuisian 3 a. hislrica seplelliriollalis drobne, f a, axial section, bu-ko 65/5435 , upper cuisian. 4 a. it. septelllriunalis drobne, r a, axial section, bu-ko 5/5283, middle cuisian 5 a. itislrica hislrica drobne, f a, axial section, bu-ko 8/5333 , middle cuisian 6 a. reclianguia drobne, [b, axial scction, bu-ko 64/541 i, upper cuisian 7 a. dislej{li/oi checchia-rispoli, [ a, axial section, bu-ko 5/5363, middle cuisian 8 a. schwageri checchia-rispoli, [a, axial section, bu-ko 6/5297, middle cuisian 9 a. melimeyeri hottinger, [a, axial section, bu-ko 6/5297, middle cuisian 10 a. alt. canavorii checchia-rispoli, f a, axial section, bu-ko7/53 16, middle cuisian ii a. cremae checchia-rispoli, r a, axial section, bu-ko 10/5375, middle cuisian all enlarged xlo, incident light drobj1(! & trlllin plate n , 7 • 4it, " , , • , .. . . ' , ~ '.:,. . " ..... /'~ .:~.~ . ..,.~;.223 , , " • 2 224 geologin croalica .'ion ,/ • , , •  conceptual model for groundwater status and risk assessment – case study of the zagreb aquifer system  zoran nakić1, stanko ružičić2, kristijan posavec1, marta mileusnić2, jelena parlov1, andrea bačani1 and goran durn2 1 department of geology and geological engineering, faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, 10000 zagreb, croatia; (zoran.nakic@rgn.hr) 2 department of mineralogy, petrology and mineral resources, faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, 10000 zagreb, croatia doi: 10.4154/gc.2013.05 geologia croatica 66/1 55–76 16 figs. 2 tabs. zagreb 2013 geologia croaticageologia croatica and fast growth of the city of zagreb have considerably affected the quality of groundwater in this area (nakić et al., 2001, bačani et al., 2002), with increasingly progressive groundwater pollution being observed over the last twentyfive years. high concentrations of pollutants including atrazine, potentially toxic metals and chlorinated hydrocarbons confirm the impact of pollution sources on groundwater quality (nakić et al., 2010). in order to identify a coherent approach to mitigation of the impacts of different pressures, (point and non-point source 1. introduction groundwater is the only source of potable water for the city of zagreb. the zagreb aquifer system, where groundwater is naturally stored, is currently under threat due to decreasing water quantity and increasing concentrations of pollutants. groundwater levels in the aquifer have particularly decreased over the last 40 years reaching such minimal levels as to cause problems to the city’s water supply during periods of drought (posavec, 2006). industrial developments ab stra ct this paper presents a conceptual model of the zagreb aquifer system. the conceptual model can be applied to groundwater status risk assessment and pollution risk assessment at the local scale, thus satisfying both environmental and preventative/limitation objectives of the water framework directive (wfd) and groundwater directive (gwd). its main purpose is to apply a risk assessment procedure, according to the wfd requirements, and to serve as a foundation for setting up a numerical model of flow in both the saturated and unsaturated zones in order to identify pressure and impact effects on groundwater quality. the model is divided into two parts, taking into account the wfd requirement to assess a risk for a wide range of source-pathway-receptor relationships. the global conceptual model (gcm) provides insight into the processes and pressures at the level of the groundwater system. it contains the geological and hydrogeological characterization of the zagreb aquifer system and the description of the most significant point and diffuse sources and pathways of pollution and processes influencing pollutant behaviour in saturated and unsaturated zone of the groundwater system. the main pollutants of the zagreb aquifer system are potentially toxic metals, nitrates, pesticides, pharmaceuticals and chlorinated aliphatics. a local conceptual model (lcm) supports parameterization of the whole groundwater system through the description of heterogeneities and flow and solute parameters of the system components at two sites representing local conditions in the saturated (stara loza) and unsaturated (kosnica) zones. this concept can be regarded as an effective tool for groundwater management of the groundwater system and its compartments and for communicating the conditions in complex groundwater systems with experts, policy makers and general public in an understandable way. keywords: global conceptual model (gcm), local conceptual model (lcm), risk and status assessment, groundwater quality, zagreb aquifer system geologia croatica 66/1geologia croatica 56 of pollution with respect to groundwater quality and overexploitation of the groundwater), a risk assessment was applied, as defined in cis document no. 26 (commission of the european communities, 2010). risk assessment tries to draw a causal chain linking the origin of a hazard or pressure (e.g. an identified or estimated loading of polluting substance) along an environmental pathway to consequences for human health or the environment. this is generally known as a source-pathway-receptor (spr) paradigm (commission of the european communities, 2010). in the context of this paper, pollution risk is related to achieving the environmental objectives of the water frame work directive (wfd, 2000/60/ec) and not in the per spective of risk to human health. in order to assess the risk of not reaching the goal of good groundwater quality in the zagreb aquifer system, the driver, pressure, state, impact, response (dpsir) analytical framework has to be followed, according to recommendations from the analysis of pressures and impacts – guidance document no 3 (commission of the european communities, 2003). according to this approach, driver is an anthropogenic activity that can affect the environment; pressure is the direct effect of a driver, and impact is an environmental effect of a pressure. state is the environmental condition resulting from the pressure and responses are the measures taken for improving the state. to apply this analytical framework, a conceptual model is needed in the form of simplified representations, or working descriptions, of the groundwater system under investigation, in this case the zagreb aquifer system. a new groundwater directive (gwd, 2006/118/ec) recognized the signi ficance of the conceptual model in the groundwater risk and status assessment, which represents, by definition, the current understanding of the groundwater system based on the knowledge of its natural characteristics (grath et al., 2007). the aim of building a conceptual model is to gain an adequate understanding of the groundwater system in order to identify pressures on the system and the relevant physical processes within it. according to the cis guidance no. 17 (commission of the european communities, 2007a), a conceptual model should describe the relevant geological characteristics, groundwater and surface water flow condifigure 1: geographical location of the zagreb aquifer system and locations of small scale experiment sites. nakić et al.: conceptual model for groundwater status and risk assessment – case study of the zagreb aquifer system geologia croatica 57 tions, hydrogeochemical (including terrestrial and aquatic ecosystems) processes, anthropogenic activities (relevant land uses) and their interactions. the accuracy and complexity of the models increases with the amount of, and confidence in, the available environmental information, so they become more effective and reliable descriptions of the system (balderacchi et al., 2011). the main focus of this paper is to describe a conceptual model that can be applied according to the wfd requirements in assessing pollution risk caused by point and nonpoint pollution sources with respect to groundwater quality in the zagreb aquifer system at different scales, ranging from the scale of the groundwater system down to a single site, representing local conditions in the saturated (stara loza site) and unsaturated zones (kosnica site). the philosophy behind this approach is to start developing adequate groundwater management of the whole zagreb aquifer system based on available knowledge of the system, and then to gain new information where needed to improve such understanding and the effectiveness of the measures applied for mitigating the risk of not achieving the environmental objectives of the wfd and gwd. in this respect, a number of iterations are expected, until the improved conceptual model can describe the measured data in a consistent way and with sufficient accuracy. the goal is to obtain a hydrogeological conceptual model of the zagreb aquifer system which will be used not only for describing, but also for quantifying the relevant geological and hydrogeological characteristics, flow and boundary conditions, hydrogeochemical processes, including natural groundwater quality and processes influencing contaminant behaviour in the unsaturated and saturated zones. 2. research area 2.1. geographical position and climate the study area (extent of the zagreb aquifer system) is situated in northwest croatia (fig. 1) and includes the city of zagreb and its surroundings, covering an area of 350 km2. the broader region is characterized by highly variable lithology, pedological features and land use. the study area consists of a large alluvial plain bordered to the north by the mt medvednica mountain chain. the alluvial plain has two marked geomorphological features: the raised sealed terrace of the sava river (varying in width down the rivers length), and a holocene terrace. numerous meanders of the sava ri­ ver inundated fluvial cones and numerous bowl­shaped depressions abound in the alluvial plain. the climate of the city of zagreb is classified as a moderately continental climate (cfwbx in the köppen climate classification system) with four separate seasons. summers are warm, and winters are cold, without a discernible dry season. the average temperature in winter is −0.5 °c and the average temperature in summer is 22.0°c. the average rainfall on the basis of ten years observations (1998–2008) is 928 mm year–1 (croatian meteorological and hydrological service). figure 2: simplified exploration core according to šimunić & basch (1975). geologia croatica 66/1geologia croatica 58 of a wide variety of soil types. the floodplain soils, formed in materials eroded from sediments present in the catchment basin, are represented by specific mineralogical, chemical and textural characteristics. the investigated area of the zagreb aquifer system encompasses predominantly three pedologic units: fluvisols, stagnic podzoluvisols (pseudogley) and eutric cambisols, developed on holocene deposits (bogunović et al., 1998). fluvisols (ac profile) are found on alluvial plains, river fans and valleys (fao, 1998). this type of soil is characterized by weak horizon differentiation, although a distinct ahhorizon may be present. the texture of these soils is mainly loam, rarely clayey loam, while the structure is crumb to blocky (romić et al., 2005)1. stagnic podzoluvisols (ap­ba­bwr­cr profile) is a hydromorphic soil which belongs to the stagnosol class. stagnosols occur on flat to gently sloping land in cool temperate to subtropical regions with humid to perhumid climate conditions (fao, 2007). in the study area, this type of soil developed from luvisols, i.e. it is secondary in origin, with a silty-clay-loam texture and a granular and very unstable structure (romić et al., 2005)1. eutric cambisols (a­bv­r profile) belong to the cambic class of soils, characterized by a cambic horizon. cambisols are characterized by slight or moderate weathering of the parent material and by the absence of appreciable quantities of illuviated clay, organic matter, al and/or fe compounds (fao, 2007). in the study area, this type of soil has a humus­ accumulative horizon which is mainly mollic and noncalcareous, developed by pedogenc processes from rendzine on marls and holocene deposits. the texture of this soil is silty­ clay to clay-loam (mainly loamy), developed on marls and holocene deposits, respectively (romić et al., 2005)1. the fluvisol type of soil is developed at small scale kosnica and stara loza experiment sites, and is texturally mainly loamy, in some parts clayey with loam. structure of this type of soils is mainly granular. in some parts, soil horizons are red to black in colour, due to fe and mn oxides enrichments. 3. conceptual model development the primary purpose in developing the conceptual model of the zagreb aquifer system was to serve as a foundation for setting up a numerical model of flow and transport in the sa­ turated and unsaturated zones, in order to identify pressure and impact effects on groundwater quantity and quality. how ever, over time, its purpose has been extended and it can now be regarded as a tool for communication with experts, policy makers, or the general public, and can provide the basis for the derivation of measures for groundwater protection. with relation to the wfd objectives, the conceptual a small scale experiment site in the unsaturated zone is located near the village of velika kosnica, about eight hundred metres from the right bank of the sava river (45°46’ n; 16°05’ e) (fig. 1). the location is close (straight line distances) to zagreb airport (3.5 km), the zagreb bypass (250 m) and the largest croatian landfill site jakuševec (4.5 km). a small scale saturated zone experiment site is located in the area of the abandoned water abstraction site at stara loza on the left bank of the sava river (45° 47’ 37’’ n, 15° 52’ 33’’ e) (fig. 1). 2.2. geological setting the geology of the studied area is described in the explanatory notes for basic geological map of sfry 1:100 000 (basch, 1983; šikić et al., 1979; pikija, 1987). the zagreb aquifer system is composed mainly of quaternary sediments, which have been studied in detail by ši­ munić & basch (1975). four horizons of marshy­loess and three horizons of fluviatile deposits were recognised in a 120 m long exploration core (fig. 2). šikić el al. (1979) and šikić & basch (1975) consider that detailed division of the pleistocene deposits of the western part of the zagreb environs is difficult, apart from division into genetic types, which are pondy-loess, continental loess without carbonates, alluvial deposits of the third sava river terrace and cave­fillings. lower pleistocene deposits are predominantly composed of yellowish-red, yellowish-orange and yellowish-brown, clayey silts/silty clays with sporadic lenses and interbeds of gravelly-sands, up to a few decimetres in thickness. highly variable coefficients of sorting, compared to the average values, possibly indicate that loess, mixed with local materials (loessoid) has contributed to the sediment composition (velić & durn, 1993). the middle pleistocene unit is relatively uniform in composition. while the lower and middle part is predominantly composed of grey coloured sands, the upper part comprises grey coloured or red to yellowish-brown mottled silt and clay sized material. during warmer periods, the top of these sediments were exposed to pedogenic processes (velić & durn, 1993; velić & saftić, 1996). the upper pleistocene unit is characterized by frequent lateral changes of gravels, sands, silts and clays. in the upper part, varves are recognized, as alternating, millimetre thick light coloured, fine­grained sands and dark grey to black silts. the holocene is composed of pale, yellowish­ grey coloured gravels and sands in which limestone cobbles prevail. both small scale experiment sites are situated in the holocene sediments. 2.3. pedological settings the large heterogeneity of the parent material, combined with the climate and geomorphology, has caused the development 1 romić, d., romić, m., dolanjski, d., stričević, i., ondrašek, g., maurović, n., kondres, n., husnjak, s. & hengl, t. (2005): održivost agro­ekosustava na području grada zagreba s obzirom na onečišćenost teškim metalima. [the sustainability of agro-ecosystems of city of zagreb with respect to potentially toxic metals contamination -in croatian] unpubl. report. faculty of agriculture, university of zagreb, zagreb. nakić et al.: conceptual model for groundwater status and risk assessment – case study of the zagreb aquifer system geologia croatica 59 model of the zagreb aquifer system is intended to assess the risk of failing to achieve good groundwater status. in setting up the conceptual model, separate components have been taken into account. firstly, subsurface characteristics and dominant processes in the saturated and unsaturated zones of the zagreb aquifer system have been address ed and incorporated in the model. then, hydrogeological parameters are quantified and variables are introduced that quan tify the exchange of fluxes between different compartments, e.g. exchange of water between the shallow aquifer and the sava river. the current stage of construction focuses on qualifying the significance of point and non­point pollution sources on groundwater deterioration. it is recognized that in evaluating the anthropogenic activities and their interactions, anthropogenic and nonanthropogenic effects need to be clearly distinguished. hence, relevant natural occurring substances in the groundwater system are identified and the importance of the natural background load assessment is highlighted. it is also recognized that, in relation to the objectives set, there is a knowledge gap in understanding the behaviour of the groundwater system at small and medium scales, with regard to its heterogeneity and the determination of groundwater pathways and mixing rates. according to the wfd requirements, risks need to be assessed for a wide range of source-pathway-receptor relationships, at scales from the very local through the medium scale, (for example, impact on individual abstraction boreholes or terrestrial ecosystems) to whole groundwater bodies (commission of the european communities, 2010). hence, further improvement of the conceptual model of the zagreb aquifer system is made according to the recommendation of cis guidance no. 15 (commission of the european communities, 2007b). the model is divided into two parts: a) global conceptual model (gcm), which provides an insight into the processes at the level of groundwater system and b) local conceptual model (lcm), which supports parameterization of the groundwater system through small scale experiments conducted at two sites: kosnica, which provides an insight into the behaviour of contaminants in the unsaturated zone and stara loza, which pro vides an insight into small scale heterogeneity. the development of both types of conceptual models and the current understanding of the groundwater system and its compartments are presented here. this paper further investigates the sources of contamination and contaminants in the urban water cycle that are directly linked to the deterioration of groundwater status in the area of the city of zagreb. due to multiple pollution sources and the wide range of potential hazards in this highly urbanized region, it is quite difficult to estimate exactly the risks of not meeting the wfd objectives. however, risks can be managed to some extent by using information about the sources of contamination and contaminant behaviour in the subsurface. 3.1. concept of groundwater status and risk assessment conceptual models are considered as a vital tool to support the implementation of all aspects of groundwater requirements of the wfd and gwd (commission of the european communities, 2009). it is clear that both the groundwater status and risk assessment should be based on a well developed conceptual model of a groundwater system. in the status assessment, a clear understanding of the behaviour of pollutants which characterize bodies of groundwater as being at risk of not meeting the wfd objectives is needed, which is also linked to the pressure and impact analysis (risk assessment), in relation to the validation of article 5 of the wfd. if the water body fails to meet its objectives, or is at risk of failing to meet its objectives, then the cause of the failure (i.e. the pressure or combination of pressures) must be investigated (commission of the european com munities, 2003). the potential benefit of the conceptual model of the zagreb aquifer system is not only in using it to assess the risk of failing to achieve good groundwater status of the system (groundwater bodies within the aquifer system), but also to estimate the risk of pollution at a local scale, thus satisfying the prevent/limit objectives in the wfd and gwd. however, in case of such localized pollution it is necessary to use the conceptual model to assess the overall risk for the groundwater system/body and to take measures to limit the pollution. this approach is followed in estimating the vulnerability of the zagreb aquifer system to potentially toxic metal pollution at the kosnica site. the idea is to estimate the leakage potential of the potentially toxic metal pollution load through the unsaturated zone at a local scale and to use risk assessment procedures to estimate the concentration range of selected potentially toxic metals in the soil and the unsaturated zone, which may be considered as an acceptable addition of human influence to the natural background concentration load that doesn’t represent a threat to the relevant receptor, (in this case groundwater itself). by using numerical modelling of transport through the unsaturated zone, the potential of this zone to retard potentially toxic metals may be as sess ed, as a basis for subsequent calculation of background concentrations in the unsaturated zone. this approach is in line with the concept of reimann & garrett (2005), who proposed the introduction of ambient background concentration, which occurs under slightly altered conditions, when elevated levels of element concentrations in soil or water result from long-term human impact such as agriculture, industry, and urbanization and are no longer natural. 3.2. global conceptual model (gcm) a global conceptual model (gcm) of the zagreb aquifer system provides an overview of the processes which occur at the level of the groundwater system. it contains the geological and hydrogeological characterization of the aquifer system, including the definition of boundary conditions and conclusions of the sensitivity analysis of the factors influencing groundwater recharge. to distinguish between natural and man-made concentrations, the natural background loads of selected inorganic parameters in the groundwater are identified, reflecting natural processes unaffected by human activities. the concept of the risk assessment implies geologia croatica 66/1geologia croatica 60 that the impact of human activity on the groundwater system should be defined, specifically those impacts that threaten the achievement of the objectives of the wfd. to that end, the most significant sources and pathways of pollution and processes influencing pollutant behaviour in saturated and unsaturated zone of the zagreb aquifer system are identified and specifically outlined here. 3.2.1. geological model of alluvial aquifer system the aquifer system comprises two quaternary aquifers (figs. 3 and 4). hydrogeologically, the quaternary deposits are divided into three basic units: the overburden of clay and silt; a shallow holocene aquifer of medium­grain gravel mixed with sands; and deeper aquifers from the middle and upper pleistocene, with frequent lateral and vertical alterations of gravel, sand and clay. 3.2.2. hydrogeological characterization the zagreb aquifer system (fig. 1) is an alluvial unconfined aquifer with a water table connected to the sava river (fig. 3). sava river represents the main source of recharge. the general groundwater flow direction is from west to east, or south-east. although recharge also occurs from precipitafigure 3: schematic hydrogeological cross-section of the zagreb aquifer system. figure 4: 3d geological model of the zagreb aquifer system. figure 5: negative trends of groundwater levels. nakić et al.: conceptual model for groundwater status and risk assessment – case study of the zagreb aquifer system geologia croatica 61 tion, alteration in the sava river water levels dominantly influence the changes in groundwater levels across the whole aquifer. the quantity of groundwater is diminishing continuously (fig. 5). the main reasons for lowering of groundwater levels are (1) extensive riverbed erosion due to upstream sava river regulation in the republic of slovenia and gravel exploitation from the river; (2) embankment of the sava river which stopped occasional flooding of the area and potential infiltration to groundwater; (3) excessive abstraction for municipal and industrial needs; and (4) prolonged periods of drought. groundwater levels have already reached minimum levels (defined as the upper elevations of the well screens) on some well fields, causing water scarcity during droughts (posavec, 2006). analysis of the water quantity data of the zagreb aquifer system showed that groundwater levels are declining on average at 1–2 m every 10 years (bačani et al., 2010). the total annual abstraction from the zagreb well fields exceeds the annual renewable groundwater reserves (which from 1997 – 2007 averaged about 107×106 m3 per year), while pumping in the same period averaged about 125×106 m3 per year. groundwater abstraction rates which exceed renewable groundwater reserves are recovered from the permanent groundwater reserves. the volume of permanent groundwater reserves in 1977 was 1.81×109 m3 and by 2007 was 1.68×109 m3, which is a decrease in permanent groundwater reserves of 7% (bačani et al., 2010). the sava river, which is the largest river in croatia, divides the zagreb aquifer system into two parts. the river, (which is the main source of groundwater recharge within the aquifer system), is in direct hydraulic connection with the shallow aquifer, which has extremely high values of hydraulic conductivity (up to 3000 m/day). head contour map analysis (posavec, 2006) showed that during high sava river water levels, infiltration to ground­ water occurs over all parts of the flow while during medium and low water levels the river drains groundwater on some parts of the flow. groundwater levels are also strongly affected by the small river dam. an average drop of the sava river water level amounts to 0,4 m/km, while the drop of the water level downstream from the dam can be up to 6 m over a rather small distance of tens of metres. this strongly affects the aquifer flow directions and groundwater levels in near vicinity of the river dam (fig. 6). the thickness of the unsaturated zone of the zagreb aquifer system varies from 8 metres in the nw part to 2 metres figure 6: river dam location and head contour maps showing the impact of the dam on groundwater flow direction in its near vicinity. geologia croatica 66/1geologia croatica 62 figure 7: isopach map of the unsaturated zone according to ružičić et al. (2011). figure 8: boundary conditions of the zagreb aquifer system. nakić et al.: conceptual model for groundwater status and risk assessment – case study of the zagreb aquifer system geologia croatica 63 in the se part (fig. 7). an isopach map of the unsaturated zone is derived from differences of groundwater level and terrain elevations. groundwater level data were collected from 406 wells by the state meteorological and hydrological service and water supply and drainage company. the zone consists predominantly of gravels and sands, with sporadic clays. the upper part is dominated by silty to sandy material, with the lower part being mostly gravel. in some parts this material is interbedded with clay layers. hydraulic conductivity of the unsaturated zone of the zagreb aquifer system varies from 1.26 m/day in the upper part to 1015 m/day in the lower part. this zone is predominantly composed of quartz, calcite, dolomite and plagioclase in the upper part, while clay minerals represent the dominant mineral phases in the lower part. 3.2.3. boundary conditions the zagreb aquifer is an aquifer with no flow boundary to the north, an inflow boundary to the west and south and an outflow boundary to the east (fig. 8). the dirichlet boundary condition specifies the value of the head at the boundary. the neumann boundary condition specifies the flux normal to the boundary and the cauchy boundary condition specifies the head and the flux normal to the boundary. determination of inflow/outflow/no flow boundaries was based on analysis of head contour maps for high, medium and low groundwater levels (posavec, 2006). the results showed that there is no significant inflow or outflow through the nort­ hern aquifer boundary, possibly due to the mainly impermeable deposits of mt. medvednica which results in predominantly surface flow. inflow quantification through the southern boundary is rather difficult due to lack of data and observation wells. bas ed on head contour map analysis and water balance analysis it can be assumed that some inflow through southern boundary does exist but with rather different fluxes across the region. boundaries within the aquifer are represented by the sava river which is the dominant boundary condition (fig. 8). in order to identify and quantify the relevance of the impact of land­use and climate effects on groundwater flow in general, sensitivity analysis of the recharge boundary condition, i.e. infiltration from precipitation, was carried out on existing numerical groundwater flow model of the zagreb aquifer. for simulation of groundwater flow, a numerical method, i.e. modflow code was identified and used as an appropriate simulation model according to defined goals. a numerical model for groundwater flow was established, ca­ librated and validated for the whole of the zagreb aquifer. sensitivity analysis of the recharge boundary condition, i.e. infiltration from precipitation, carried out on an existing figure 9: regression models showing zones of higher impact of the sava river. geologia croatica 66/1geologia croatica 64 numerical groundwater flow model of the zagreb aquifer, has shown that recharge from precipitation does not present the relevant boundary condition. the sava river was defined as the dominant and the most relevant boundary condition. spatial zonation of areas where the sava river has a high er impact on groundwater levels was analyzed using recession curve models. the analysis of groundwater level time series using recession curve models was performed with the master recession curve tool (posavec et al., 2006). in total, 278 master recession curves were obtained for the 278 observation wells analysed. analysis of the spatial distribution of the selected regression model showed that logarithmic regression prevails in parts of the aquifer near the river sava, while polynomial regression prevails in other parts of the aquifer (fig. 9). these results are logical and reasonable with respect to the changes in groundwater levels which occur faster in the vicinity of the sava river. in other parts of the aquifer where such strong boundaries do not exist, groundwater level changes occur less rapidly. principal component analysis (pca) – following the pro cedure by winter et al. (2000) – can be used to define hydrodynamic zones within the regional groundwater system with identical groundwater table changes or fluctuation patterns in time. this procedure was implemented in the zagreb case study, as part of the sensitivity analysis, pointing to aquifer recharging conditions and enabling conclusions on prevalent groundwater flow conditions in parts of the zagreb aquifer system to be drawn. results of the pca, implemented in the zagreb case stu dy example (nakić, 2005), enabled characterization of the groundwater fluctuation pattern at the locations of observation wells, revealing diversity of hydrodynamic characteristics in different parts of the groundwater system (fig. 10). on the right bank of the sava river the groundwater fluctuation pattern is similar for the shallow and deeper layers, and it mainly reflects the impacts of the regional groundwater flow from the west towards the east. at the edge of the aquifer system, the impact of the sava river is less and the water wave propagation is significantly lagging in time, while in the zone located immediately next to the sava river, intensive fluctuations in the groundwater tables reflect the rapid and intensive impacts of changes in river water levels on the groundwater tables. further evidence of the sava river – groundwater interaction has been provided by nakić et al., (2004), who delineated hydrogeochemically homogenous areas within the zagreb aquifer system, using the phreeqc groundwater modelling tool (parkhurst et al, 1980) and cluster analysis, more specifically the ward method of hierarchical tree clustering. they revealed the very similar or identical macro chemical composition of groundwater in the area bordering figure 10: hydrodynamic zones within the zagreb aquifer system according to nakić (2005). nakić et al.: conceptual model for groundwater status and risk assessment – case study of the zagreb aquifer system geologia croatica 65 the river, which supports the evidence of strong impacts of the sava river water levels on the groundwater levels adjacent to the river. these results were confirmed by hydrogeochemical investigations, conducted by vlahović et al. (2009). it was proven that the direct exchange between the sava river and the aquifer weakens with distance away from the river, while the difference in hydrogeochemical characteristics between the sava river water and groundwater increases. to identify the pattern of groundwater – sava river water interaction, comprehensive investigations of isotopic composition in precipitation, groundwater and river water were carried out. horvatinčić et al., (2011) and parlov et al. (2012) used measurements of stable isotopes of oxygen and hydrogen in precipitation, surface waters and groundwater in order to determine the relative contributions of the sava river and precipitation on groundwater recharge along the left (horvatinčić et al., 2011) and right (parlov et al. 2012) banks of the sava river respectively. the results of these investigations are combined in figure 11, which indicates the relationship between δ2h and δ18o in: the sava river and groundwater at the left bank of the sava river in 2010 (horvatinčić et al., 2011); groundwater and bundek lake at the right bank of the sava river in 2011 (parlov et al., 2012). for illustration purposes, long term records of zagreb precipitation (1980–2003) and the local meteoric water line (lmwl) (vreča et al., 2006) are also included (fig. 11). it can be seen that all groundwater values lay very close to the correlation line of the sava river showing its direct influence on the groundwater. differences between particular piezometers indicate the temporal and spatial variability in groundwater-surface water (sava river) interactions. accordingly, mixing of water from the sava river and groundwater is occurring in the near vicinity of the sava river and it weakens further away. analyses of the recharge boundary condition presented here show that recharge from precipitation does not represent an important boundary condition in the zagreb aquifer system. due to the identified high impact of the sava river levels on groundwater levels, the sava river is defined as the dominant and the most relevant boundary condition in the numerical model. changes in the sava river levels are naturally related to climate scenarios, but primarily in the upper parts of the flow where the sava river is fed by surface runoff and by groundwater drainage. since the course of the sava river through the zagreb area is characteristic of the valley river, it doesn’t drain the whole zagreb aquifer, yet it controls the processes of recharge and drainage. therefore in the case of the zagreb aquifer, (i.e. an alluvial aquifer with high hydraulic conductivity and a water table connected to the stream with significant oscillation in water levels due to lack of regulation), the stream i.e. the sava river represents the dominant boundary condition. 3.2.4. natural groundwater quality and ambient background values development of industry and the fast growth of the city of zagreb during the last three decades have considerably affected the quality of the groundwater in the zagreb aquifer system. the zagreb area accommodates an extremely high number of diverse diffuse and point pollution sources causing degradation of groundwater quality and posing a particular threat for its future use. although human activity may lead to water compositions which exceed drinking water standards, water quality limits may be also breached for elements such as f, as and fe by entirely natural processes, the result of geochemical conditions existing in aquifer or due to the specific geology in the area (edmunds & shand, 2008). groundwater pollution is most easily recognised by the presence of artificial organic compounds, but it is difficult to recognise incipient pollution in most groundwaters. in order to be sure that pollution is occurring, natural spatial and temporal characteristics and trends of the chemical substances must be ascertained. under such conditions, it is particularly important to make a clear distinction between geogenic and anthropogenic influences in groundwater quality. this is aided by determination of the geochemifigure 11: relationships between δ2h and δ18o in the waters of the zagreb area. geologia croatica 66/1geologia croatica 66 cal background of naturally occurring substances which re flect natural processes unaffected by human activities. the new gwd (2006/118/ec), which introduces the term background level, as: „the concentration of a substance or the value of an indicator in a body of groundwater corresponding to no, or only very minor, anthropogenic alterations to undisturbed conditions” particularly recognises this. although the term geochemical background was introduced much earlier in the scientific terminology by hawkes & webb (1962), who defined it as the normal abundance of an element in barren earth material, human influences on the planet as a whole have been so pervasive for such a long time that it may be pointless to attempt to determine presettlement background values, because concentrations from presumed pristine areas in these locations are likely to have also been affected (kelly & panno, 2008). an option is to define ambient background values under slightly altered conditions, when elevated levels of element concentrations in soil or water result from long-term human impact, such as agriculture, industry and urbanization, and are no longer natural (reimann & garrett, 2005). the geochemical background is a response to variable recharge rates, rainfall composition, water-gas interactions in soil and the unsaturated zone, as well as the processes (mineral dissolution, redox reactions, ion-exchange reactions and mixing) that have taken place along flow paths. under natural conditions, groundwater quality is determined by the sum of soil­modified atmospheric inputs plus water­rock interactions taking place at the soil-bedrock interface and from longer-term reactions taking place in the saturated zone. in order to fully understand the evolution of groundwater chemistry along a flow path, in depth knowledge of the background and pollution loads in soils and unsaturated zone is needed. research into soil geochemistry in the area of the zagreb aquifer system was carried out in different professional and scientific projects at different scales. for the „geochemical atlas of the republic of croatia”, a total of 640 topsoil (0–25 cm) samples were collected in the central croatian region using systematic sampling on a 5km grid (halamić & miko, 2009). numerous studies of metal contamination of soils have been made in the area of zagreb and zagreb county (namjesnik, 1994; miko et al., 2001; romić, 2002; romić & romić, 2003; romić et al., 20045; ha­ lamić & miko, 2009; sollitto et al., 2010). a total of 420 topsoil (0–15 cm) samples were collected, using systematic sampling on a 2km grid, with sampling density increasing to 1 km near the urban part of zagreb (namjesnik, 1994). sollitto et al. (2010) collected 916 topsoil (0–20 cm) samples in the zagreb county. compendious results for potentially toxic metals in soils from these studies, together with maximum permissible concentrations in agricultural soils defined by croatian government regulation (og, 2010) are presented in table 1. it is evident that in some areas of zagreb concentrations of cadmium, chromium, cooper, mercury, nickel, lead and zinc in soil exceed maximum permissible concentrations. the vertical distribution of trace elements in soil profiles has been extensively studied, mainly in order to define the mobility of certain contaminants from soil to groundwater. about 70 vertical profiles of soil were studied in the area of zagreb and zagreb county. the department of field crops, forage and grassland from the faculty of agriculture carried out agricultural soil trace element contamination studies in the framework of several projects (romić et al., 20036; romić et al., 20045; romić et al., 20051). romić (2002) investigated twelve profiles of the most abundant soil types. profile depths and thicknesses of layers from which the samples were taken vary, depending on soil type and morphological features. the results of the aforementioned investigations show that cadmium, iron, manganese and nickel have increased concentrations with depth, while concentrations of lead, zinc, chromium and copper vary. table 1: geochemical topsoil data for the city of zagreb and surrounding area from different studies (data from geochemical atlases and maximal permissible concentrations from croatian legislation are for comparison). element official gazette (2010) namjesnik (1994) sollito et al. (2010) geochemical atlas of the republic of croatia (halamić & miko, 2009) croatia zagreb zagreb county central croatia croatia maximal permissible concentration min max min max med min max med min max med * ** *** cd (mg/kg) 0.5 1.0 2.0 0.01 22.5 0.02 4.94 0.31 0.2 9.4 0.2 0.2 15.5 0.4 cr (mg/kg) 40 80 120 9 161 11.5 400 51.2 28 524 74 18 524 88.2 cu (mg/kg) 60 90 120 – – 3.64 1335 23.5 3 248 19 3 429 25.4 hg (μg/kg) 500 1000 1500 18 1938 – – – 5 4535 50 5 4535 60 ni (mg/kg) 30 50 75 4 651 0.7 488 29.7 12 427 33 9.2 427 47.5 pb (mg/kg) 50 100 150 5 546 1 216 19.6 14 217 27 10 699 33 zn (mg/kg) 60 150 200 12 1250 27.1 479 70.7 28 477 73 23 1432 88 legend: * – sandy soil; ** – silty-loamy soil; *** – clayey soil. nakić et al.: conceptual model for groundwater status and risk assessment – case study of the zagreb aquifer system geologia croatica 67 since the wfd (2000/60/ec) came into force, several hydrogeochemical investigations of the zagreb aquifer system have been undertaken with the aim of characterising the dominant geochemical processes and sources influencing na­ tural groundwater chemistry. nakić (2001) and bačani et al. (2002) used statistical methods, trend analysis and multivariate statistical analyses, in order to discriminate between natural and man-made concentrations on a qualitative basis. brkić et al. (2003) studied the intrinsic vulnerability of the zagreb aquifer system, while nakić et al. (2004) outlined hydrogeochemically homogenous areas within the zagreb aquifer system by multivariate statistical analyses and geochemical modelling tools, showing that it is possible to differentiate a shallow holocene alluvial aquifer from the deep er middle/upper pleistocene lacustrine-marsh aquifers. in order to distinguish between geogenic and anthropogenic influences in groundwater quality of the zagreb aquifer system, background levels of inorganic substances were calculated on several occasions (table 2), using model-based objective statistical methods (nakić et al., 2007; nakić et al., 2008). pre-settlement background values of elements were not determined due to the extensive temporal impact of human activity in the zagreb area. an option used was to define ambient background values under altered conditions, according to the concept set out by reimann & garrett (2005). for this purpose, the visual basic macro background, created by nakić et al. (2007) was applied as it uses algorithms that incorporate model-based objective statistical methods (the iterative 2-σ technique and the calculated distribution function), as defined by matschullat et al. (2000). overall, the ranges of ambient background values for the selected chemical substances reflects local geological and geochemical conditions in the aquifer system as well as the slight impact of anthropogenic sources, e.g. agricultural activities or atmospheric inputs due to emissions from the burning of fossil fuels. with respect to no3, ambient background includes sources such as soil organic matter from the residue of fertilized and unfertilized crops, products of combustion, and evaporation of ammonia (nh3) from synthetic and organic n fertilizer and livestock waste, in addition to naturally derived no3. at first glance, it seems that ranges of ambient background values for particular chemicals, e.g. for sulphate are wide, however comparison to the range of estimated background values from european aquifers (see e.g. shand & edmunds, 2008), suggests that values reflect the specific groundwater chemistry in the zagreb aquifer system. similar evidence can be provided for the other elements and compounds under consideration. variable ambient background ranges of iron and manganese are due to rapidly chang ing concentrations of these elements across redox boun daries in the zagreb aquifer system. as a consequence, concentrations may vary over four to five orders of magnitude across the shallow and deeper aquifers. 3.2.5. sources and pathways of pollution, pollutants and their behaviour groundwater of the zagreb aquifer system is facing increasing pressure from human activities and there is a threat of contamination by diffuse and point sources. pathways from sources to receptors are outlined in figure 12. the main point pollution sources in the area of the zagreb aquifer system include the jakuševec city landfill site, marshalling yard, wastewater treatment plant, septic tanks, illegal waste depositories, gravel pits, industrial facilities, zagreb airport, fuel stations and domestic households. the main diffuse pollution sources are traffic, leaky sewage pipes and agriculture (use of liquid manure, composted materials and agrochemicals such as fertilizers and pesticides). these sources can generally be divided into active (permanent and temporary) and potential sources of pollution. the permanent sources of pollution include the location of wastewater discharges, wastewater treatment plant, septic tanks, leaky sewage system, semi-legal disposal of municipal and industrial waste, abandoned gravel pits covered with municipal and construction waste. temporary sources of pollution include storm water discharge locations, tailings disposal in open pit mines, manure and other waste materials dumps from farms, storm drainage system wastewater, and other agricultural activity (bačani et al., 2010)2. potential sources of pollution can occur due to failures, malfunctions or negligence (e.g. active and abandoned gravel pits). pollutants, causing regional or local pollution which, depending on soil properties and hydrogeological conditions, table 2: local ambient background values of selected chemical parameters in groundwater of the zagreb aquifer system. chemical parameters normal range of ambient background values upper limits of ambient background values method of calculation source nitrate (mg n/l) 0.0 – 4.80 4.8 iterative 2-s technique nakić et al., 2007 0.0 – 5.9 5.9 calculated distribution function dissolved oxygen (mg/l o2) 1.4 – 8.4 1.4* iterative 2-s technique nakić et al., 2008 sulphate (mg/l so4) 14.2 – 47.6 47.6 iterative 2-s technique nakić et al., 2008 chloride (mg/l cl) 1.7 – 35.3 35.3 iterative 2-s technique nakić et al., 2008 iron (mg/l fe) 0.0 – 11.4 11.4 iterative 2-s technique nakić et al., 2008 manganese (mg/l mn) 0.0 – 0.5 0.5 iterative 2-s technique nakić et al., 2008 * for dissolved oxygen a lower limit of ambient background value is applicable to determine the outliers below background fluctuation (low values of dissolved oxygen as indicators of extreme oxygen consumption) geologia croatica 66/1geologia croatica 68 may reach groundwater, can be divided into natural substan­ ces: (1) potentially toxic metals; (2) radionuclides; (3) road salt; (4) nutrients (mainly nitrogen); and synthetic substances: (1) pesticides; (2) chlorinated aliphatics and petroleum hydrocarbon contaminants; (3) organic wastewater contaminants (balderacchi et al., 2011). potentially toxic metals, nitrates, pesticides, pharmaceuticals and chlorinated aliphatics are the main pollutants of the zagreb aquifer system. pathways of pollutants from the sources of pollution to the environmental receptors (atmosphere, soil, vegetation, sava river, quaternary alluvial sediments) ending in the groundwater of the zagreb aquifer system are shown in fig. 12. they include: fallout from the atmosphere onto vegetation, soils, sediments and surface waters; runoff from the soil/sediment surfaces and other urban surfaces to the sava river and other surface waters; flooding of the sava river onto the zagreb floodplain; weathering of rocks and sediments; leaching from point sources (e.g. jakuševec landfill) and polluted soils and sediments. potentially toxic metals groundwater concentrations of lead exceed the maximum permitted concentrations in some locations though the overall trend is one of decreasing levels as a consequence of a reduction in the use of leaded petrol. in some wells, the concentration of manganese is extremely high (bačani et al., 2007)3. the occurrence and concentration of mn in groundwater is controlled by many factors, the main ones being rock geochemistry, water chemistry and microbiological activity. water chemistry, in particular ph, redox potential (eh), dissolved oxygen (do), and dissolved organic carbon (doc) influence mobilisation of mn and control its speciation and concentration in the water environment. micro-organisms can play an important role in mn mobilisation in the environment and can both enhance or inhibit concentrations in groundwater. the impact of microbiological activity on mn behaviour in water is frequently evident in the accumulation of mn oxides on pipe surfaces. there is also the threat of potentially toxic metals leaching from point sources and polluted soils and sediments to the figure 12: the most significant anthropogenic sources (grey boxes), pathways (arrows) and receptors (white and black boxes) of pollution in the area of the zagreb aquifer system. nakić et al.: conceptual model for groundwater status and risk assessment – case study of the zagreb aquifer system geologia croatica 69 groundwater. nakić et al. (2007), in their study of ground­ water quality at the jakuševec landfill indicated such leaching of potentially toxic metals into both soil and groundwater. different studies of soils and sediments in zagreb aqui fer area indicated elevated concentrations of following trace elements: cu, hg, zn, pb, cd, ni, as. halamić et al. (2003) showed that the spatial distribution of cu in topsoils of the zagreb area was mostly related to the winegrowing areas, i.e. to the anthropogenic input of this metal into the topsoil. they also assumed that anomalous values of as and cd are mainly of natural origin (mineralization). greater amounts of hg in topsoil of zagreb area were probably caused by fossil fuel combustion and airborne pollution from industrial plants (namjesnik et al., 1992). aljinović et al. (1995)4 highlighted higher concentrations of lead in the topsoil of kosnica and assumed traffic to be the source. elevated concentrations of zn, pb and cd in topsoils of the zagreb aquifer system are a consequence of the atmospheric deposition of particles from urban sources such are industrial emissions, traffic, waste disposal, heating plants, etc. (romić et al., 2004)5. higher concentrations of hg, cd and ni as observed in the vertical profile of soils in water protected areas of the zagreb aquifer system (romić et al., 2005)1 are probably related to airborne deposition and traffic. anomalous concentrations of nickel in the vicinity of the highway and the airport result from anthropogenic influences due to fuel combustion (romić & romić, 2003). high nickel concentrations are probably partly connected to the morphogenetic characteristics of the wider region, primarily basic and ultrabasic magmatic rocks of the surrounding mountain range. nitrates sporadically high concentrations of nitrates are registered in the groundwater beneath the city of zagreb, especially at the mala mlaka well field. it was confirmed that periodically high nitrate concentrations are a consequence of agricultural production (nakić et al., 2001; petošić et al., 2012). nitrogen is present in soils as the nitrate ion (no3–), ammonium ion (nh4+) and as a component of soil organic matter. nitrate leaching from soil depends on the amount, frequency and intensity of precipitation, soil properties, crop type and crop development stage, evaporation, soil tillage practices, and nitrogen fertilization regime (vidaček et al., 1996, 1999; nemeth, 2006; josipovic et al., 2006; nemčić et al., 2007). romić et al. (2003)6 found that high concentrations of nitrates result from flushing of previously unsaturated layers during periods of high rainfall. soil solution in arable soil contains 20–40 mg no3-n/l, rising more than tenfold after fertilization (romić et al, 2003)6. as nitrates are very soluble in water, leaching to groundwater is highest when precipitation exceeds evapotranspiration and for irrigated land at the beginning of the vegetation growing period. although intensive agriculture (nitrogen and organic fertilizer) is the main potential nitrate pollution source in the zagreb area, other sources include leakage from septic tanks and the sewage system, atmospheric deposition and other urban waste, as well as accident situations. pesticides pesticides present in the groundwater of the zagreb aquifer system originate mainly from agricultural use and can be dispersed in the environment by diffuse and point sources. diffuse pesticide pathways into groundwater are mainly leaching through the soil and the unsaturated zone. point sources mainly concern farmyard runoff, septic tank leakage, accidental spills, plumes from landfills and poor handling of pesticides. gojmerac et al. (2006) found high concentrations of atrazine in the groundwater of the velika gorica well field. groundwater samples from observation wells during 2000–2010 show ed that atrazine occasionally exceeded the maximum permissible concentration beneath agricultural areas (ba ča ni & posavec, 2011)7. soils with high pesticide concentrations occurred at kosnica (romić et al., 1995)8. this contamination resulted from infiltration through the unsaturated zone which has a high filtration coefficient favouring the undisturbed transport of contaminants. the continued presence of these pollutants over time reflects the persistence of atrazine and other pesticides. agricultural pesticide inputs into the soil and groundwater are dependent on various factors. at the field scale, inputs into soil depend on spraying, crop interception and wash-off, losses through spray drift or volatilization processes (balderacchi et al., 2011). pesticide pathways to groundwater mostly depend on: (1) sorption processes, which control the amount of pesticide available for leaching into the soil and aquifer, and (2) on transport processes through the soil and the unsaturated zone (jarvis, 2007; kohne et al., 2009b). such processes are strongly dependent on the physical, physicochemical and biological properties of soils. atrazine for example, can be detected in groundwater several years after the last application (baran et al., 2008; morvan et al., 2006; tappe et al., 2002) because it has slow remobilization from the soil and the unsaturated zone. chlorinated aliphatics chlorinated aliphatics are some of the most widespread ground water contaminants in the industrialised world (kästner, 1991; wilson, 1996). because of spills and accidents, these hydrocarbons have become important contaminants in both soil and groundwater (schaerlaekens et al., 1999). the contamination associated with chlorinated aliphatics and petroleum hydrocarbon compounds is typically of a point source such as: landfill with municipal and industrial wastes; leaky sewage collecting leachate from small industrial activities (e.g. dry-cleaning; metal degreasing); petrochemical activities; leakage of underground storage tanks. some of them are primary compounds in industrial processes, some are by-products of degradation. many are recalcitrant, but under favourable conditions (especially anaerobic) they can be transformed and degraded through microbially mediated processes which include reductive dechlorination, dehydrochlorination and dichloroelimination (ferguson & pietari, 2000). tetrachlorethylene (pce) concentration in all wells with in the zagreb aquifer system is relatively high, and in some cases geologia croatica 66/1geologia croatica 70 exceeding the maximum permitted concentrations (bačani et al., 2007)3. mobility of tetrachlorethylene (pce), a dense non-aqueous phase liquid (dnapl), is described as moderate (fetter, 1988). in the presence of water, pce will form a separate phase. the half-life degradation rate in groundwater is estimated to be between 1 – 2 years, based on aqueous aerobic biodegradation (howard et al., 1991), but may be considerably longer under certain conditions. organic wastewater contaminants recent research, carried out in the zagreb area, within the framework of the implementation of eu directives, is partly related to the determination of the qualitative status of the groundwater (bačani & posavec, 2011)7, and it confirmed that part of the aquifer system is endangered from or­ ganic pollutants. organic wastewater contaminants include pharmaceuticals, surfactants, flame retardants, plasticizers and sterols. pharmaceuticals represent the most studied class and are a diverse group of chemicals used as medicinal products for both humans and animals (heberer, 2002), as well as bioactive food supplements, cosmetics, fragrances, sunscreen agents, insect repellent and antiseptics (ellis, 2006). after application at hospitals or households, pharmaceuticals are excreted either in their parent form or as metabolites, and enter the aquatic systems via various pathways (fent et al., 2006). the main sources of contamination are sewagesystem leaching, sewage sludge, septic tanks, re-use of reclaimed domestic wastewater for irrigation and manure, contaminated landfill and accidental release. most of them are not eliminated during wastewater treatment (jones et al., 2005). due to the polar structure of most pharmaceutical compounds they are not significantly adsorbed in the subsoil and may leach into the groundwater aquifers from contaminated surface water (heberer et al., 1997). sediment samples from gorjak creek (a small watercourse), were analysed by terzić et al. (2011) in order to identify organic contaminants present in the polar fraction of freshwater sediment. a number of different contaminants were successfully identified including various pharmaceuticals (chlorthalidone, warfarin, terbinafine, torsemide, zolpidem, azithromycin, desmethylazitromycin, erythromycin and dehydrated erythromycin). ahel & jeličić (2000) showed that solid waste in the jakuševec landfill contains significant amounts of phenazone and propylphenazone. the attenuation of phenazone concentrations in the unsaturated zone and in groundwater seems to be much faster than the attenuation of propylphenazone. it can be assumed that the retention of phenazone com pounds by aquifer sediments is low due to their high solubility in water which indicates that abiotic and/or biotic transformations are involved. radionuclides although the manufacturing, application and disposal of man -made radionuclides are under strict regulatory control and under normal conditions only minute amounts of radioactivity are released to the environment, nuclear accidents can cause large scale radioactive pollution. horvatinčić et al. (2011) reported significant increase of tritium activity in the sava river in june 2010, as well as in groundwater (wells in the area of petruševec) with a delay for 3–5 months related to the sava river. this increase was explained by the release of tritiated water from the krško nuclear power plant 30 km upstream of zagreb. low level radioactive waste in a slag dump near the teto thermal plant, as well as low radioactive waste from hospitals, also presents potential threats to groundwater. salts the main anthropogenic source of chloride is nacl used on roads to remove ice at temperatures around 0°c. other anthropogenic sources of chloride can be dust-binding on roads, storage of salt, snow dumps, leakage from sewage and waste deposits, fertilizers and chemicals used at water and sewage treatment plants (lundmark, 2003). since chloride is a mobile compound, it will be transported to groundwater. chloride stored in the unsaturated zone will, during snowmelt, be flushed into groundwater and so increase its chloride concentration (nystén, 1998). 3.3. local conceptual model (lcm) – supporting gcm parameterization local conceptual model (lcm) supports development of the global conceptual model (gcm) through characterization of two sites representing local conditions in the saturated (stara loza) and unsaturated (kosnica) zones. as previously stated, the main goal is to estimate the risk of pol lution on a local scale through the description of heterogeneities of figure 13: sketch of the unsaturated zone profile at kosnica. nakić et al.: conceptual model for groundwater status and risk assessment – case study of the zagreb aquifer system geologia croatica 71 the groundwater system and through identification of the relevant flow and solute parameters in both the unsaturated and saturated zones. only the design of site experiments is presented here together with an outline of the main results, since both experiments are still in progress. 3.3.1. case studies 3.3.1.1. experiments in the unsaturated zone the aim of the unsaturated zone experiment is the identification of solute transport parameters, necessary for modelling the behaviour of potentially toxic metals. the catchment area of the kosnica well field was chosen for the ex periment because of its accessibility and results of previous investigations (romić et al, 19958, 20045; aljinović et al. (1995)4. a solute transport model will be the basis for the risk assessment of pollution with potentially toxic metals at a local scale. a prediction transport model of potentially tox ic metals through the unsaturated zone is based on results of field and laboratory experiments. detail characterization of the unsaturated zone profile (5 m) at kosnica, together with sedimentological, chemical and mineralogical analyses of soil and sediment samples were the basis for the experimental setup. the lower part of the profile consists of gravels with a sand component, while the upper part is dominated by gravels with silty to sandy material (fig. 13). fluvisols are developed on the top of the unsaturated zone profile. the texture of this type of soil is main ly loamy, in some parts clayey with loam, while the struc ture is mainly granular. soil ph increases while electrical conductivity generally decreases with depth. the mineral composition of the profile samples includes quartz, calcite, dolomite and plagioclase in the lower part and clay minerals mainly in the upper part. both the longitudinal dispersion coefficient (dl) and the distribution coefficient (kd) are the main para­ meters needed for modelling dispersion and sorption processes, respectively. these processes are obtained from labora tory results and will be verified by field and laboratory ex periments. in order to obtain the sorption parameters (distribution coefficient, kd) of cd, pb and zn, a laboratory batch experiment was performed on different soil samples taken from a pedological burrow. multi element solutions of different concentrations were prepared from pb(no3)2, zncl2 and cdcl2. current results from the sorption experiment showed that pb had a slightly higher affinity for sorption on these soil textures than cd and zn (ružičić et al., 2012). to obtain transport parameters and confirm this experiment, a field dispersion coefficient determination will be set up. calcium chloride solution will be used because of its rela tively low sorption potential and its suitability (seuntjens et al., 2001; akhtar m.s. et al., 2003; dişli, e., 2010). monitoring of parameters such as water content, electrical conductivity, soil water tension and concentrations of chlorides in percolating water is necessary for the calibration of models. therefore, field measurement instruments are installed in a pedological burrow located in the proximity of the profile. water content is measured using time domain reflectrometry (tdr) equipment; electrical conductivity (ec) using ec-probes (fig. 14a) and soil water tension using tensiometers (fig. 14b). the soil column laboratory experiment will also be used for determination of both the longitudinal dispersion coefficient (dl) and the distribution coefficient (kd). the longitudinal dispersion coefficient will be determined using breakthrough curves of chloride concentration. after the dispersion ex periment, soil columns will be irrigated by metal solutions 2 bačani, a., posavec, k., parlov, j. (2010.): prva faza izrade programa mjera za zaštitu i sanaciju u zonama zaštite izvorišta. [the first phase of the criterion program for the protection and rehabilitation of the water source protection zones – in croatian].– unpubl. report. faculty of mining, geology and petroleum engineering, university of zagreb, zagreb. 3 bačani, a., posavec, k., nakić, z., perković d., miletić, p., heinrich­miletić, m., parlov, j. & bazijanec, m. (2007.): elaborat zaštitnih zona vodocrpilišta grada zagreba – i. faza [study of water well protection zones for city of zagreb – first phase].– unpubl. report. faculty of mining, geology and petroleum engineering, university of zagreb, zagreb. 4 aljinović, d., miko, s., durn, g., tadej, n., kapelj, s. (1995): ispitivanje dosega prodiranja površinskog zagađenja kroz krovinu. [investigation of surface contamination leaching through unsaturated zone – in croatian].– unpubl. report. faculty of mining, geology and petroleum engineering, university of zagreb, zagreb. 5 romić, d., romić, m., dolanjski, d., stričević, i., ondrašek, g., maurović, n., kondres, n., mustać, i., husnjak, s., hengl, t. (2004): stanje onečišćenja tala na prostoru zagrebačke županije [the soil pollution state of the zagreb county area – in croatian] unpubl. report. faculty of agriculture, university of zagreb, zagreb. 6 romić, d., romić, m., dolanjski, d., stričević, i., ondrašek, n., husnjak, s., petošić, d., bašić, f., kisić, i., mesić, m., juračak, j., durn, g., brkić, ž. & borošić, j. (2003): poljoprivredna proizvodnja na vodozaštitnim područjima zagrebačke županije i grada zagreba [agricultural production in water protection areas of zagreb county and city of zagreb – in croatian].– unpubl. report. faculty of agriculture, university of zagreb, zagreb. 7 bačani, a. & posavec, k. (2011): implementacija okvirne direktive o vodama eu u dijelu koji se odnosi na kvalitativno stanje voda na zagrebačkom i samoborskom području. [the implementation of the water framework directive of the eu waters in the part relating to the status of water quality in zagreb and the samobor area].– unpubl. report. faculty of mining, geology and petroleum engineering, university of zagreb, zagreb. 8 romić, d., romić, m., stričević, i., petošić, d. & klačić, ž. (1995): istraživanje prodora potencijalnih polutanata kroz solum tla do podzemne vode na području „kosnice“ [study of potentially pollutants breakthrough through soil to groundwater at location „kosnica“].– unpubl. report. faculty of agriculture, university of zagreb, zagreb. geologia croatica 66/1geologia croatica 72 prepared from pb(no3)2, zncl2 and cdcl2 for determination of the distribution coefficients (kd). transport of potentially toxic metals is modelled using hydrus 1d (šimůnek et al., 1998). figure 15 represents development of the solute transport prediction model using parameters obtained by laboratory and field experiments. mo dels 2 and 3 will be compared to evaluate the validity of soil column experiments in modelling solute transport for the field scale. it should be stated that the experiment at kosnica can support the parameterization of the soil and unsaturated zone of a large part of the groundwater system. about 88% of the area is covered by fluvisol which is also developed at kosnica. thus, field and laboratory experiments of fluvisol at kosnica will provide the basis for a risk assessment of pollution with potentially toxic metals not only at the local scale, but also on a groundwater system scale. 3.3.1.2. experiments in the saturated zone the stara loza site is a well field previously used for croatia’s capital (zagreb) public water supply (fig. 16). it has not operated since 1997. the well field has 5 pumping wells distanced approximately 500 – 1000 m from the sava river. 15 head observation wells (11 operating) and 7 concentration observation wells (4 operating) are concentrated in the surrounding area and are still in use for monitoring of ground water levels and quality. tracer experiments in the saturated zone at stara loza were conducted in order to determine longitudinal and transversal dispersion parameters as well as the effective (seepage) velocity. the obtained parameters would then be used as the input for the prediction models of contaminant transport in the zagreb aquifer. the experiment was designed as a natural gradient tracer test, with one injection and fourteen observation wells, setup in two rows 25 and 50 m from the injection well, perpendicular to the ground water flow direction. due to the expected transverse dispersivities of 0.25 – 1.25 m and associated transverse spread of 7.0 – 15.0 m for the first row and 10.0 – 22.0 m for the second row of observation wells, the distance between wells in the first and second rows was set to 1.5 m and 3.0 m, respectively. the artificial tracer used in the experiment was uranine (na­fluores cein) which was chosen because of its good sorption behaviour and small mass (leibundgut et al., 2009). the mass of the tracer was calculated with respect to water volume and the detection limit of the tracer and the sampling frequency were calculated with respect to expected breakthrough times. for the first row of observation wells 25 m from the injection well, the sampling started 6 hours after tracer injection, and 12 hrs for the second row. the sampling campaign lasted figure 14: pedological barrow: a) installed tdr and ec probes; b) installed tensiometers. figure 15: a scheme representing development of the solute transport prediction model, using parameters obtained by laboratory and field experiments. nakić et al.: conceptual model for groundwater status and risk assessment – case study of the zagreb aquifer system geologia croatica 73 for 40 days, during which 1598 groundwater samples were taken. analysis of the tracer experiment results have shown that a major part of the uranine tracer bypassed the first row of wells possibly through small palaeomeanders or palaeochannels, but appeared in the second row of observation wells. this clearly suggests pronounced local scale heterogeneity of the aquifer and preferential flow paths, but there is a lack of scientific evidence to further support such an interpretation. therefore further research including geophysics will be conducted. 2d and 3d electrical tomography, which is generally applied in geophysical research of aquifers (šumano­ vac, 2007), is planned in order to gain a better understanding of lateral changes in lithological composition and hope fully detect preferential flow paths or palaeomeanders i.e. palaeochannels, which would give further insight into probable tracer migration paths. 4. conclusions the main purpose of developing a conceptual model of the zagreb aquifer system is to apply a risk assessment procedure through linking the origin of pollution sources along environmental pathways to consequences for the status of groundwater dependent ecosystems (gde) and groundwater itself. this will provide a baseline for achieving the environmental objectives, according to the wfd requirements. to that end, the conceptual model is intended to assess the risk of failing to achieve good groundwater and gde status through qualitative and quantitative description of real system behaviour. at the current state of knowledge and understanding of the zagreb aquifer system, it is evident that a number of iterations in the development of the conceptual model will be needed in order to accurately describe all the relevant processes within the groundwater system and pressures on it. this is particularly recognized in attempts to describe the heterogeneities of the groundwater system components at different scales and to quantify the significance and effects of point and diffuse pollution sources on the system. taking into consideration knowledge gaps in the understanding of groundwater systems, a coherent approach to assess a risk for a wide range of source-pathways-receptor relationships at different scales is applied by dividing the con ceptual model in two parts: a) global conceptual model (gcm), which gives an insight into the processes and pressures at the level of the groundwater system and b) local conceptual model (lcm), which supports parameterization of the whole groundwater system through the description of heterogeneities of the system components at a site scale and through identification of the relevant flow and solute parameters in both the unsaturated and saturated zones. the reasoning behind this approach is to use the conceptual model not only to assess the risk of failing to achieve good status of the groundwater and gde bodies within the zagreb aquifer system, but also to satisfy the preventative/limitation objectives in the wfd and gwd, by estimating the risk of pollution at a local scale. furthermore, this concept helps to extend the primary purpose of the conceptual model by developing an effective tool for groundwater management of the zagreb aquifer system, particularly through creation of the basis for delineation of groundwater protection measures figure 16: stara loza site. geologia croatica 66/1geologia croatica 74 at different scales and through communicating conditions in complex groundwater systems with experts, policy makers and the general public in an understandable way. acknowledgment the study was supported by the european community 7th framework project genesis (226536) on groundwater systems. references ahel, m. & jeličić, i. (2000): occurrence of phenazone analgesics in landfill­leachate polluted groundwater, issues in the analysis of environmental endocrine disruptors. extended abstracts of 219th national meeting of the american chemical society, san francisco, usa, march 26–30, 2000, 109–111. akhtar, m.s., steenhuis, t.s., richards, b.k. & mcbride, m.b. (2003): chloride and lithium transport in large arrays of undisturbed silt loam and sandy loam soil columns.– vadose zone journal, 2, 715–727. doi:10.2113/2.4.715 bačani, a., vlahović, t. & nakić z. (2002): endangered groundwater quality of the strmec well field.– in: ribeiro, l. (ed.): proceedings, 3rd international conference on future groundwater resources at risk, lisbon, june 25–27, 2001, 329–336. bačani, a., posavec, k. & parlov, j. (2010): groundwater quantity in the zagreb aquifer.– in: zuber, a., kania, j. & kmiecik, e. (eds.): xxxviii iah congress groundwater quality sustainability, krakow, september 12–17, 2010, 87–92. balderacchi, m., benoit, p., cambier, p., eklo, o.m., gar­ gini, a., gemitzi, a., gurel, m., klöve, b., nakić, z., preda, e., ružičić, s., wachniew, p. & trevisan, m. (2011): groundwater pollution and quality monitoring approaches at european-level.– critical reviews in environmental science and technology. doi: 10.1080/10643389.2011.604259 baran, n., lepiller, m., & mouvet, c. (2008): agricultural diffuse pollution in a chalk aquifer (trois fontaines, france): influence of pesticide properties and hydrodynamic constraints.– journal of hydrology, 358, 56 – 69. doi:10.1016.2008.05.031 basch, o. (1983): osnovna geološka karta sfrj 1:100 000. tumač za list ivanić grad l33–81 [basic geological map of sfry 1:100 000, geology of the ivanić grad sheet – in croatian]– geološki zavod, zagreb, savezni geolološki zavod, beograd, 66 p. bogunović, m., vidaček, ž., husnjak, s., sraka, m. & pe­ tošić, d. (1998): zemljišni informacijski sustav zagrebačke žu­ panije [land information system of zagreb country – in croatian].– agriculturae conspectus scientificus, 63/4: 219–231. brkić, ž., kapelj, s., larva, o., marković, t. & vlahović, t. (2003): hydrogeology and hydrogeochemistry in the alluvial aquifer of the zagreb area.– rmz­m&g vol. 50, no.1, 75–78. commission of the european communities (2003): analysis of pressures and impacts. guidance document no 3. isbn 92– 894–5123–8, european communities, luxembourg. commission of the european communities (2007a): gui­ dance on preventing or limiting direct and indirect inputs in the context of the groundwater directive 2006/118/ec. guidance document no 17. technical report – 2007 – 012. isbn 978­92 ­ 79­06277­3, european communities, luxembourg. commission of the european communities (2007b): gui­ dance groundwater monitoring. guidance document no 15. technical report – 2007 – 002. isbn 92­79­04558­x, european communities, luxembourg. commission of the european communities (2009): guidance on groundwater status and trend assessment. guidance document no 18. technical report – 2009 – 026. isbn 978­92­79­ 11374­1, european communities, luxembourg. commission of the european communities (2010): guidance on risk assessment and the use of conceptual models for groundwater. guidance document no 26. technical report – 2010 – 042. isbn 13 978­92­79­16699­0, european communities, luxembourg. dişli, e. (2010): batch and column experiments to support potentially toxic metals (cu, zn and mn) transport modelling in alluvial sediments between the mogan lake and the eymir lake gölbaşi, ankara.– ground water monitoring & remediation 30/3, 125–139. doi: 10.1111/j.1745­6592.2010.01302.x edmunds, w.m. & shand, p. (2008): natural groundwater quality – summary and significance for water resources management.– in: edmunds, w.m. & shand, p. (eds.): natural groundwater quality, blackwell publishing ltd., 441–462. ellis, j. b. (2006): pharmaceutical and personal care products (ppcps) in urban receiving waters.– environmental pollution, 144/1, 184 – 189. doi:10.1016/j.envpol.2005.12.018 elzahabi, m & yong, r.n. (2001): ph influence on sorption characteristics of potentially toxic metal in vadose zone.– engineering geology, 60, 61–68. doi:10.1016/s0013­7952(00)00089­2 fao (1998): fao–unesco soil map of the world: revised legend.– world soil resources rep 60. fao/unesco/isric, rome. fao (2007): fao – unesco world reference base for soil resources, first update. fao/unesco/isric, rome. fent, k., weston, a., & caminada, d. (2006): ecotoxicology of human pharmaceuticals.– aquatic toxicology, 76/2, 122–159. doi:10.1016/j.aquatox.2005.09.009 ferguson, j.f. & pietari, j.m.h. (2000): anaerobic transformations and bioremediation of chlorinated solvents.– environ. pollut., 107, 2, 209–215. doi:10.1016/s0269­7491(99)00139­6 fetter, c.w. (1988): applied hydrogeology. 2nd edition.– merrill pub, columbus, 592 p. gojmerac, t., ostojić, z., pauković, d., pleadin, j. & žu­ rić, m. (2006): evaluation of surface water pollution with atrazine, an endocrine disruptor chemical, in agricultural areas of turopolje, croatia, bull. environ.– contam. toxicol. 76/3, 490–496. doi: 10.1007/s00128­006­0947­5 grath, j., ward, r., scheidleder, a. & quevauviller, p. (2007): report on eu guidance on groundwater monitoring developed under the common implementation strategy of the water frame work directive.– journal of environmental monitoring, 9, 1162–1175. doi: 10.1039/b710665n halamić, j., galović, l. & šparica, m. (2003): potentially toxic metal (as, cd, cu, hg, pb and zn) distribution in topsoil developed on alluvial sediments of the drava and sava rivers in nw croatia.– geol. croat., 56/2, 215–232. halamić, j. & miko, s. (eds.) (2009): geochemical atlas of the republic of croatia.– croatian geological survey, zagreb, 87 p. hawkes, h.e. & webb, j.s. (1962): geochemistry in mineral exploration.– harper and row, new york. heberer, th. & stan, h.j. (1997): determination of clofibric aci­ dand n-(phenylsulfonyl)-sarcosine in sewage, river and drinking water.– int. j. environ. anal. chem., 67, 113–124. doi:10.1080/ 03067319708031398 heberer, t. (2002): occurrence, fate, and removal of pharmaceutical residues in the aquatic environment: a review of recent research data.– toxicology letters, 131, 5–17. doi:10.1016/s0378­4274(02) 00041-3 horvatinčić, n., barešić, j., krajcar bronić, i., obelić, b., kármán, k. & fórizs, i. (2011): study of the bank filtered groundwater system of the sava river at zagreb (croatia) using nakić et al.: conceptual model for groundwater status and risk assessment – case study of the zagreb aquifer system geologia croatica 75 isotope analyses.– central european geology, vol. 54/1–2, 121– 127. doi: 10.1556/ceugeol.54.2011.1–2.12 howard, p.h., boethling, r.s., jarvis, w.f., meylan, w.m. & michalenko, e.m. (1991): handbook of environmental degradation rates. printup, h.t. (ed.).– lewis publishers, chelsea, mi. jarvis, n. j. (2007): a review of non­equilibrium water flow and solute transport in soil macropores: principles, controlling factors and consequences for water quality.– european journal of soil science, 58/3, 523–546. doi: 10.1111/j.1365–2389.2007.00915.x jones, o.a.h., voulvoulis, n., & lester, j.n. (2005): human pharmaceuticals in wastewater treatment processes.– critical reviews in environmental science and technology, 35/4, 401–427. doi:10.1080/10643380590956966 josipovic, m., kovačević, v., šostarić, j., plavšić, h. & liovic, j. (2006): influences of irrigation and fertilization on soybean properties and nitrogen leaching.– cereal research communications, 34/1, 513–516. doi: 10.1556/crc.34.2006.1.12 kästner, m. (1991): reductive dechlorination of triand tetrachloroethylenes depends on transition from aerobic and anaerobic conditions.– appl. environ. microbiol., 57, 2039–2045. kelly, w.r. & panno, s.v. (2008): some considerations in applying background concentrations to ground water studies.– ground water, 47, no. 6: 790–792. doi:10.1111/j.1745­6584.2008.00467.x kohne, j. m., kohne, s. & šimůnek, j. (2009b): a review of model applications for structured soils: b) pesticide transport.– journal of contaminant hydrology, 104, 36–60. doi:10.1016/j.jconhyd.2008.10.003 lin, y.p., teng, t.p., & chang, t.k. (2002): multivariate analysis of soil potentially toxic metal pollution and landscape pattern in changhua county in taiwan.– landsc. urban plan., 62/1, 19–35. doi:10.1016/s0169-2046(02)00094-4 lundmark, a. (2003): predicting environmental impact of de-icing salt – a modelling approach.– report 2003–10–23, dept. of land and water resources engineering, kth. matschullat, j., ottenstein, r. & reimann, c. (2000): geochemical background – can we calculate it?– environmental geology, 39/9, 990–1000. doi: 10.1007/s002549900084 miko, s., halamić, j., peh, z. & galović, l. (2001): geochemical baseline mapping of soils developed on diverse bedrock from two regions in croatia.– geol. croat., 54/1, 53–118. morvan, x., mouvet, c., baran, n., & gutierrez, a. (2006): pesticides in the groundwater of a spring draining a sandy aquifer: temporal variability of concentrations and fluxes.– journal of contaminant hydrology, 87, 176–190. doi:10.1016/j.jconhyd.2006. 05.003 nakić, z., bačani, a. & vlahović, t. (2001): antropogeni utjecaj na podzemne vode crpilišta strmec (zagreb, hrvatska) [anthropogenic influence on groundwater of the strmec well field (zagreb, croatia) – in croatian with an english abstract].– rudarsko-geološko­naftni zbornik, 13, 25–38. nakić, z. & horvat, s. (2002): analiza hidrokemijskih podataka primjenom multitivarijatnih statističkih metoda na priljevnom po­ dručju crpilišta petruševec [petruševec well field catchment area hydrochemical data analysis by multivariate statistical methods – in croatian].– hrvatske vode, 40, 271–290. nakić, z., posavec, k. & parlov, j. (2004): hydrogeochemical model of the heterogeneous aquifer system: the case of zagreb, croatia.– in: groundwater flow understanding from local to regional scales, congress xxxiii – 70 alhsud, zacatecas city. nakić, z. (2005): određivanje hidrodinamičkih zona [determination of hydrodynamic zones – in croatian, with an english abstract].– građevinar, vol. 57, no. 6, 413–421. nakić, z., prce, m. & posavec, k. (2007): utjecaj odlagališta otpada jakuševec­prudinec na kakvoću podzemne vode [impact of the jakuševec-prudinec waste disposal site on groundwater quality – in croatian, with an english abstract].– rudarsko­geološko­ naftni zbornik,19, 35–45. nakić, z., posavec, k. & bačani, a. (2007): a visual basic spread­ sheet macro for geochemical background analysis.– ground water 45, 642–647. doi: 10.1111/j.1745­6584.2007.00325.x nakić, z., posavec, k., kontrec, p., bačani, a. & parlov, j. (2008): geochemical background values of selected chemical pa­ ra meters in groundwater of zagreb aquifer system.– in: taniguchi, m., yoshioka, r., skinner, a., aureli (eds.): a. xxxvi iah congress, integrating groundwater science and human well-being, toyama. nakić, z., posavec, k. & parlov, j. (2010): model­based objective methods for the estimation of groundwater geochemical background.– aqua mundi, 1, 65–72. doi: 10.4409/am­010­10­0010 namjesnik, k., palinkaš, l., miko, s., durn, g., polić, d. & kvrgnjaš, l. (1992): lead, zinc, nickel and mercury in soil along road sides and of some rural and urban parts of zagreb, croatia.– rudarsko­metalurški zbornik, 39, 93–112. namjesnik, k. (1994): distribucija teških metala u tlima grada zagreba i njegove okolice. [potentially toxic metals distribution in the soils of zagreb and surrounding – in croatian].– master thesis. university of zagreb faculty of science and faculty of mining, geology and petroleum engineering, zagreb, 63 p. nemčić jurec j., mesić m., bašić f., kisić i. & zgorelec, ž. (2007): nitrate concentration in drinking water from wells at three different locations in northwest croatia.– cereal research communication, 35/2, 533–536. doi: 10.1556/crc.35.2007.2.92 nemeth, t. (2006). nitrogen in the soil­plant system nitrogen balances.– cereal research communications, 34/1, 61–64. nystén, t. (1998): transport processes of road salt in quaternary formations.– in: nystén, t., & suokko, t. (eds.): de-icing and dust binding – risk to aquifers.– proceedings of an international sym posium, nhp report no. 43, nordic hydrological programme, helsinki, 31–41. og (2010): pravilnik o zaštiti poljoprivrednog zemljišta od onečišćenja [regulation on protection of agricultural land from pollution – in croatian].– official gazette nr. 32/10. parkhurst, d.k., thorenston, d.c. & plummer, n.l. (1980): phreeqe – a computer program for geochemical calculations. u.s. geological survey water resource investigations, 80–96. parlov, j., nakić, z., posavec, k. & bačani, a. (2012): origin and dynamics of aquifer recharge in zagreb area.– in: morell, m. (ed.): international conference on water, climate and environment, balwois 2012, ohrid, republic of macedonia. petošić, d., husnjak, s., petošić, b. & mustać, i. (2012): im­ pact of agriculture upon groundwater pollution in the city of zagreb water-conservation area.– in: morell, m. (ed.): international conference on water, climate and environment balwois 2012, ohrid, republic of macedonia. pikija, m. (1987): osnovna geološka karta sfrj 1:100 000. tumač za list sisak l33–93 [basic geological map of sfry 1:100 000, geology of the sisak sheet – in croatian].– geološki zavod zagreb (1986), savezni geolološki zavod, beograd, 64 p. posavec, k. (2006): identification and prediction of minimum groundwater levels of zagreb alluvial aquifer using recession curve models.– unpubl. dissertation, university of zagreb, faculty of mining, geology and petroleum engineering, 89 p. reimann, c. & garret, r.g. (2005): geochemical background – concept and reality. science of the total environment, 350, 12–27. doi:10.1016/j.scitotenv.2005.01.047 geologia croatica 66/1geologia croatica 76 romić, m. (2002): sadržaj, oblici i preraspodjela imisije teških metala u poljoprivrednim tlima šireg područja zagreba [content, forms and redistribution of potentially toxic metals imision in the agricultural soils of broader area of zagreb – in croatian].–doctoral thesis. faculty of agriculture, university of zagreb, zagreb, 219 p. romić, m. & romić, d. (2003): potentially toxic metals distribution in agricultural topsoils in urban area.–environmental geology, 43, 7, 795–805. doi:10.1007/s00254­002­0694­9 ružičić, s., mileusnić, m. & durn, g. (2011): unsaturated zone of zagreb aquifer.– in: banjac, n. (ed.): geology in digital age, proceedings of the 17th meeting of the association of european geological societies. belgrade, 2011, 203–208. ružičić, s., mileusnić, m. & posavec, k. (2012): building conceptual and mathematical model for water flow and solute transport in the unsaturated zone at kosnica site, mining-geologicalpetroleum engineering bulletin, vol. 25, 21–31. schaerlaekens, j., mallants, d., šimůnek, j., van genuchten m. th. & feyen, j. (1999): numerical simulation of transport and sequential biodegradation of chlorinated aliphatic hydrocarbons using chain_2d.­hydrological processes, 13, 2847– 2859. doi: 10.1002/(sici)1099–1085(19991215) seuntjens, p., mallants, d., toride, n., cornelis, c. & geu zens, p. (2001): grid lysimeter study of steady state chloride transport in two spodosol types using tdr and wick samplers.– journal of contaminant hydrology, 51, 13–39. doi:10.1016/s0169­ 7722(01)00120­6 shand, p. & edmunds, w.m. (2008): the baseline inorganic chemistry of european groundwaters.– in: edmunds, w.m. & shand, p. (eds.): natural groundwater quality, blackwell publishing ltd., 22–59. sollitto, d., romić, m., castrignano, a., romić, d. & ba­ kić, h. (2010): assessing potentially toxic metal contamination in soils of the zagreb region (northwest croatia) using multivariate geostatistics.– catena 80, 182–194. doi:10.1016/j.catena.2009.11.005 šikić, k. & basch, o. (1975): geološka zbivanja od paleozoika do kvartara u zapadnom djelu zagrebačke regije. [geological events from paleozoic to quaternary period in west part of zagreb region – in croatian].-2nd scientific congress section for application of geology, geophysics and geochemistry. scientific advisory board for petroleum jazu, zagreb, a/5, 69–86. šikić, k., basch, d. & šimunić, a. (1979): osnovna geološka karta sfrj 1: 100.000. tumač za list zagreb, l 38–80 [basic geological map of sfry 1:100 000, geology of the zagreb sheet – in croatian].– institut za geološka istraživanja, zagreb (1972), savezni geo lo ški zavod, beograd, 81 p. šimůnek, j., šejna, m. & van genuchten, m. th. (1998): the hydrus­1d software package for simulating the one­dimensional movement of water, heat, and multiple solutes in variably-saturated media, version 2.0. igwmc­tps­70, international ground water modeling center, colorado school of mines, golden, colorado, 162 p. šimunić, a. & basch, o. (1975): stratigrafija kvartarnih sedimenata zagrebačkog posavlja. [quartary sediments stratigraphy of the zagreb posavlje region – in croatian].– geol. vjesnik, 28, 153–164. tappe, w., groeneweg, j., & jantsch, b. (2002): diffuse atrazine pollution in german aquifers.– biodegradation, 13/1, 3–10. doi: 10.1023/a:1016325527709 terzić, s. & ahel, m. (2011): nontarget analysis of polar contaminants in freshwater sediments influenced by pharmaceutical industry using ultra-high-pressure liquid chromatography-quadrupole time­of­flight mass spectrometry.– env. pollution, 159, 2, 557–566. doi: 10.1016/j.envpol.2010.10.009 velić j. & durn, g. (1993): alternating lacustrine­marsh sedimentation and subaerial exposure phases during quaternary: prečko, zagreb, croatia.– geol. croat., 46/1, 71–90. velić j. & saftić, b. (1996): dubinskogeološki odnosi područja smet lišta „jakuševec“ – čimbenik sanacije [deep geological relationship of city landfill „jakuševac” recovery factor – in croatian] waste managment, iv. international symposium, zagreb, 197–205. vlahović, t., bačani, a. & posavec, k. (2009): hydrogeoche­ mical stratification of the unconfined samobor aquifer (zagreb, croatia).– environ. geol., 57/8, 1707–1722. doi: 10.1007/s00254­ 008-1452-4 vidaček, ž., bogunović, m., sraka, m. & husnjak, s. (1996): water discharges and nitrates from some soils of the sava river valley. 6. gumpensteiner lysimetertagung „lysimeter in dienste des grundwassershutzes”.– bal, gumpenstein, 111–115. vidaček, ž., sraka, m., čoga, l. & mihalić, a. (1999): nitrates, potentially toxic metals and herbicides in soil and water of karasica­vučica catchment area.– agriculturae conspectus scientificus, 64/2, 143–150. vreča, p., krajcar bronić, i., horvatinčić, n. & barešić j. (2006): isotopic characteristics of precipitation in slovenia and croatia: comparison of continental and maritime stations.– j. hydrology, 330, 457–469. doi: 10.1016/j.jhydrol.2006.04.005 wedepohl, k. h. (1995): the composition of the continental crust.– geochimica et cosmochmica acta, 59, 7, 1217–1232. doi:10.1016/0016­ 7037(95)00038­2 wilson, j. (1996): chlorinated solvents biodegradation, epa, groundwater water curr., 16, 1–4. manuscript received september 18, 2012 revised manuscript accepted november 19, 2012 available online february 28, 2013 geologia croaticageologia croatica ab stra ct in this study two small, but genetically related iron carbonate deposits mačje jame and vranjski potok, south west of busovača (mbsm), located in the pre-devonian metamorphic complex were investigated in detail. analyses of the main chemical components, trace elements, ree, isotope composition of c, o, s, 87sr/86sr ratio of rhyolite, plot of ree normalized to ci chondrites and a microscopic study of thin and polished sections were performed. three mineralization phases were identifi ed: the oldest is the main phase (90-95 wt %) with fe (ca, mg, mn) carbonates (siderite, ankerite, fe-dolomite) as the predominant minerals, whereas magnetite, haematite, albite, allanite, pyrite i, quartz i represent subordinate minerals. the second phase is the pneumatolytic-kata-thermal phase (5-10 wt %) characterized by pyrrhotite relicts, pyrite ii, quartz ii, arsenopyrite and some supposed accessory minerals such as cassiterite, wolframite, gersdorffi te, and columbite. the youngest is the kata-meso-epithermal-hydatogene phase (<1 wt %) which gave quartz iii-chalcedony as gangue mineral and marmatite, chalcopyrite, boulangerite, gel-pyrite-marcasite, sphalerite, enargite, tetrahedrite, galena, cosalite, bismuth and sternbergite as ore minerals. an almost identical paragenesis has been observed in the oldest ore deposit of the gemericum palaeozoic metamorphic complex (radvanec and bartalsky, 1987). the fi rst and second mineralization phase of both ore deposits formed in the carboniferous from metamorphogenohydrothermal fl uids generated from s-granitoid magmatic rocks and their protoliths. this claim is strongly supported by very similar ree and their interior disposition between these deposits and metarhyolites as well as by the obtained strontium ratios. the third, youngest phase is the product of a very weak overprint of hydrothermal activity in the late variscan (290-260 ma) and in the upper permian-lower triassic (260-240 ma). keywords: iron deposits, mačje jame, vranjski potok, hercynian metallogeny, mid-bosnian schist mts. geologia croatica 67/2 145–161 3 figs. 9 tabs. 2 pls. zagreb 2014 geochemical characteristics and genesis of mačje jame and vranjski potok as-cu-bearing iron occurrences west and southwest of the town of busovača, mid-bosnian schist mountains (mbsm)  ivan jurković1 and hazim hrvatović2 1 faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, zagreb, croatia 2 federal geological institute for geology, 71210 ilidža, republic of bosnia and herzegovina doi: 10.4154/gc.2014.11 the north-eastern side, by the kozica river on the south-eastern and southern sides, by the krušćica river on the southwestern side and by the lašva river on the north side. the mačje jame deposit is located in the spring zone of the kozica river in the živčička mt. similar paragenetic but smaller ore occurrences were observed at the rudno 1. introduction the busovača region with the mačje jame and vranjski potok ore deposits is situated in the north-eastern part of the mid-bosnian schist mountains (mbsmts) (fig. 1). it is the oldest part of mbsmts. the palaeozoic complex area (3000 km2) is delimited by the deep fi rst order busovača fault on geologia croatica 67/2geologia croatica 146 with 23-26 mol % of a mg-chloritoid component; c) chlorite richer in the mg-component and d) barroisitic type amphibole. majer et al., (1991) carried out a phase analysis of pyrophyllite, white micas, chlorite, chloritoid and amphibole from the metamorphic rocks in the busovača-fojnicakiseljak-kreševo region. these analyses demonstrated very low to low grade metamorphism of rocks in the sw part of the mbsm, and the local presence of barroisitic amphibole in the ne part of this territory (south of busovača) indicating higher p t conditions. 2.2. variscan rocks the silurian metaclastic formations, scarcely intercalated with pelagic limestone chert interlayers and metavolcanic rocks are represented by slates, phyllites, quartz-muscovite schists, black graphite-bearing quartzitic schists, chloritemuscovite-quartz schists, chloritoid schists, calcic phyllites (calcareous schists) with subordinate pyrophyllite schists, metasandstones and quartzites (karamata & krstić, 1996, hrvatović, 1996, 2006). according to majer et al., (1991) the predominant variscan rocks of silurian age contain phengitic muscovite with less than 10 mol % celadonite, chloritoid with mainly 8-15 mol % of mg-chloritoid component and chlorite rich in the fe-component. these rocks were generated under low-grade p-t conditions ranging between 350 400°c and approximately 300-400 mpa. a group of pyrophyllite-bearing rocks originated under p-t conditions of 350-430°c and 300-400 mpa. the first dating of the mbsm rocks was performed on a phyllite sample from the fojnica area by balogh at the institute of debrecen, hungary, palinkaš et al., (1996). the obtained k-ar age of 343 ± 13 ma suggests a middle viséan (carboniferous) thermometamorphic event, a metamorphic overprint of an inferred pre-variscan complex in the busovačafojnica region (pamić et al., 2004). devonian. the silurian rocks are overlain by massive reef limestones, dolomites, locally marbles characterized by tabular coral favosites vranicae and stromatoporoid amphipora ramosa. lower parts of the carbonate sequence belong to the early devonian (emsian), whereas the upper parts belong to the middle devonian, mostly to the eifelian and to a lesser extent to the givetian (živanović, 1979). upper devonian formations, which belong to the frasnian, contain conodont ancyrodella ooids (živanović, 1972), only recorded at the village of dusina. mudrenović et al., (1969) consider that greywackesandstones, without fossils, which overlie devonian layers with conodonts at jezero (jajce) are of the lower carboniferous age. živanović and milojević (1975) stated that argillites and clay shales at medenik (rostovo), although without fossils, but covering fossiliferous devonian sediments must be attributed to the lower carboniferous. vuj nović (1981) included greywacke sandstones and chlorite-sericite schists with locally rare phyllite breccias located at the village of komar (travnik), into the lower carboniferous. a dry land period existed from the end of the lower carboniferous to the upper permian. mountain ridge (+843 m) locality, sw of the village of tisovac and at the locality of gornje brizove stijene, 6.5 km se to the town of busovača. these small ore occurrences are characterized by siderite and ankerite as the main minerals, with subordinate magnetite, haematite, albite, pyrite, quartz and fe, as, cu, zn, pb and sb sulphides and sulphosalts. mining investigations at the locations of rudno and brizove stijene only involved the oxidation zone of both ore occurrences, whereas the mačje jame deposit had been mined in the primary ore zone as well (katzer, 1905, 1910, 1924) (fig. 1). the vranjski potok ore deposit is situated on the west bank of the vranjski potok (creek), 150 m above its bed. the ore occurrence is located in the strongly tectonized palaeozoic metasandstone of pre-devonian age, approximately ten metres thick. metasandstones are fine to coarse-grained rocks giving the appearance of a conglomerate (fig. 2). green-grey metarhyolite is located at the footwall of the metasandstone, in the duboki potok creek, the tributary of the krušćica river. the ore deposits are friable at the outcrops and the interstices are filled with limonite and different sulphides. the most abundant mineral is quartz, followed by muscovite as deformed ribbons, while sericitized feldspars, pyrite, limonite and clay minerals are sporadic. layers of quartz and mica-schists, mm-cm thick, are interbedded in the faulted host rock. 2. geology 2.1. pre-variscan metamorphic rocks the oldest rocks in the mid-bosnian schist mountains (mbsmts) are phyllites and mica schists, interlayered with metavolcanics, amphibolites and flaser gneisses. these rocks are exposed in a zone several km long at modri kamen and zahor in the busovača region. katzer (1906,1924) interpret ed these rocks as being azoic. živanović and milojević (1975) interpreted them as being of ordovician age. karamata and krstić (1996) supposed a cambrian-ordovician age for these rocks. according to pamić and jurković (2002) and pamić et al., (2004), the pre-variscan meta morphic rocks could be compared not only to the ötztal complex of the eastern alps, but also to palaeozoic metamorphic complexes of the drina-ivanjica area (sw serbia) and of eastern macedonia. according to hrvatović (1999, 2006) the oldest rocks in the mbsm are ordovician metaclastics and metabasalt. dinaridic cambrian-ordovician formations were metamorphosed during the late ordovician deformation, under p-t conditions of greenshist facies, and to a lesser extent of epidote-amphibolite facies (400-500°c; 4-5 kbars), in conformity with the statement of matté (1984) for central europe (pamić et al., 2004). a detailed microscopic study performed by majer et al. (1991) of the pre-variscan metamorphic rocks (cambrianordovician) in the busovača zone demonstrated a significant difference compared to the silurian-devonian variscan rocks. the pre-variscan rocks include: a) phengitic muscovite containing more than 10 mol % celadonite; b) chloritoid ivan jurković and hazim hrvatović: geochemical characteristics and genesis of mačje jame and vranjski potok as-cu-bearing iron occurrences ... geologia croatica 147 figure 1: simplified geological map of the northeastern part of the mid bosnian schist mountains. figure 2: vranjski potok ore deposit. on the right side of this photo are visible outcrops of thick banded coarse-grained quartz sandstones and conglomerates inserted with different ore and gangue minerals. geologia croatica 67/2geologia croatica 148 three upper permian formations have been identified: (1) upper permian bojska series in the region of bugojno, kalin; (2) upper permian opara series; (3) permotriassic series in the area of travnik. 2.3. variscan magmatic rocks detailed microscopic and chemical investigations of quartzporphyry and metaquartz porphyry of vranica mountain (2107 m) and albite porphyry of sinjakovo (jajce) were conducted by jurković and majer (1954). the rocks have been identified as rhyolites, metarhyolites and albite rhyolite, generated from magma of a leucogranitic-aplitic character. southwest of jezero-jajce, near the village of aljinovac, in the western tributary to the peručica river, the authors established contact metamorphism between albite rhyolite and crinoid limestone at that time supposed to be of lower permian age (katzer, 1906, 1924. geological map (m 1: 200 000). in addition, on vranica mountain they established contact metamorphism between rhyolites and at that time con sidered carboniferous phyllite. further data concerning chemical compositions of the mbsm rhyolites are found in the explanations of the basic geological maps (m 1 : 100 000). according to živanović and milojević (1975), four successive eruptive phases of rhyolites in the mbsm have been established: the first phase as shallow silurian intrusions in the gornji vakuf area; the second phase between the lower carboniferous and the upper permian; the third phase, very subordinate, during the permo-triassic and the last phase, only locally in the lower triassic. živanović (1979) and jovanović et al. (1978) presented the case for a two-stage magmatic history: 1) the older stage resulted in porphyrite sills found in the silurian muscovite-chlorite schists (1pz) and quartz-sericite schists (3pz), and 2) the younger one which occurred in carboniferous-permian time and produced quartz porphyries penetrating silurian and devonian rocks, thus causing contact metamorphic changes in carbonate rocks. they considered that quartz keratophyres were partly carboniferouspermian and partly triassic in age. trubelja (1978) and sofilj et al. (1980) suggested that metarhyolites intruded as intrusive and extrusive rocks during carboniferous and early permian time. they considered that quartz keratophyres are partly of triassic age. hrvatović (1996, 2006) considers that most of rhyolites are synsedimentary with presumed silurian metasediments and are of silurian age. some hypabyssal rhyolites intruded into the late silurian and early devonian limestones which also occur as xenoliths within the volcanic body. large masses of pyroclastics are either interlayered with metaclastics or represent shallow hypabyssal bodies. majer and garašić (2001) defined the composition of the major elements, compatible elements (ni,cu,co) as well as incompatible elements with low (k, rb, ba, th) and high ionic potential (y, zr, nb). a low content of compatible elements and a high content of incompatible elements in rhyolites compared to the average contents in chondrites prompted the authors to express their doubt as to the juvenile origin of rhyolites from the mantle, and to attribute them to a crustal origin. jurković et al. (2010a) determined in one vranica mountain rhyolite sample an extremely high 87sr/86sr ratio of 0.776995 ± 2 s, performed by thermal ionisation mass spectrometry (tims) in the activation laboratory, ancaster, ontario, canada. this high strontium ratio of rhyolite might indicate the crustal source of an s-type of granitoid magma. 3. paragenesis of the mačje jame and vranjski potok ore deposits a significant difference exists between the paragenesis of the ancient, abandoned mine mačje jame characterized by opened primary and oxidation ore zones and the paragenesis of the recently discovered ore locality vranjski potok, open only in the oxidation zone. the difference is also between host rocks: schists are present in the mačje jame and meta sandstones (conglomerates) in the vranjski potok ore deposit. 3.1. petrography of ore and gangue minerals 3.1.1. the ore deposit mačje jame jurković conducted the first unpublished microscope study of the mačje jame ore and gangue minerals as early as 1956a and 1958 (references). these minerals were identified exclusively under polarizing microscope using thin transparent (petrographic) and polished ore sections (hereinafter marked with an asterisk, *). quantitative values of their amounts were performed exclusively by recalculation from chemical analyses performed during this study (20122013), displayed in tables 2a, 2b, 4a, 4b, 5a, 5b, 6a, 6b and 9b. minerals marked with a dot (●) were identified by combining microscopic analyses and analyses of trace elements and ree analyses. minerals identified by trace element analyses, anticipating genetic type of ore deposits, are marked with a symbol (○). minerals identified during this study using optical methods are marked with a symbol (**). the earliest phase of mineralization which makes up 90 to 99 % of the ore, is characterized by different fe-mgca-mn carbonate minerals (siderite, ankerite, dolomite) as the main minerals, and by subordinate magnetite, haematite, albite and scarce pyrite i and quartz i. magnetite i. (*, content: < 5 wt%) is the earliest mineral component, idiomorphically developed, isometric, and marginally martitized. haematite i (*, content: < 5 wt%) is rodshaped, rodlike formed, 1-4 mm long, 30-60 μm thick. it forms parallel, radial, or bent bundles densely or thinly scattered within carbonates. basal cross–sections or irregular small aggregates are very rare. a significant amount of haematite i was transformed into magnetite ii (*) most probably at the beginning of the sulphide phase. particular bundles and even particular sticks of haematite i were replaced to different degrees during the process of reduction in which enlargement of magnetite ii crystals occurred, and therefore the margins are less acute (plate i, photo 1, 2, 5). calculation of amounts of irregularly martitized magnetite and oxidized haematite were not calculated individually but alongside goethite. siderite (*, content: 64.7 wt %), is in rombohedral habit with a diameter of up to 0.5 mm. these crystals build up subparallel or radial bundles as siderite ii. in table 9 isomorphic components of the mačje jame siderite-ankerite ivan jurković and hazim hrvatović: geochemical characteristics and genesis of mačje jame and vranjski potok as-cu-bearing iron occurrences ... geologia croatica 149 table 1: paragenesis of the mačje jame deposit (table 1a) and vranjski potok deposit (table 1b) located in the mbsmts (captions: see text). parageneses method of identification mačje jame method of identification vranjski potok analyte wt. % wt. % quartz (sio2) * 5.665  61,000 albite (k(na)alsi3o8) * 5.680  0,570 siderite (fe,ca,mg,mn)co3 * 45.695 – pyrite (fes2) * 3.090  – arsenopyrite (feass) * 1.745  0,018 magnetite (fe3o4) * see content of goethite – haematite (fe2o3) * marmatite (zn,fe)s * 0.107 – tennantite (tetrahedrite) * 0.086 – chalcopyrite (cufes2) * 0.058  1,993 boulangerite (pb5sb4s11) * 0.029 – chalcedony (sio2xh2o) * <0.100 – cassiterite (sno2) * 0.024  0,006 galena (pbs) * 0.018 – wolframite (fe,mn)wo4) ● 0.012 – cosalite (pb2bi2s5) ● 0.010  0,058 sphalerite (zns) ● <0.010  0,023 enargite (luzonite) (cu3as(sb)s4) * <0.005 – sternbergite (agfe2s3) * <0.005 – silver (ag) * ppm <1.6  0,001 gold (au) ● ppm 0.029  0,339 bismuth (bi) ● <0.010  0,329 molybdenite (mos2) ○ <0.001  0,0004 barite (baso4) ● 0.004  0,040 cobalite (coass) ○ 0.022  – gersdorffite (niass) ○ 0.030 – columbite (femn) (nb,ta)2o6 ○ 0.012  – allanite (ce,y)•(al,fe)3(sio4)3•oh ** <0.100  – trace elements (tr-el) ● 0.071  0,109 ree ● 0.017  0,018 goethite (feo•oh) + magnetite + haematite * 39.315  26,955 kaolin (al2si2o5(oh)4) ppm ○ 56.800  10,164 calcite (caco3) * trace – pb-as-sb oxydes ● trace  >0,016 (feo, cao, mgo and mno) ore samples were calculated: 62.5 wt % feco3; 8.8 wt % caco3; 19.3 wt % mgco3 and 9.4 wt% mnco3. these values are significantly elevated, particularly the values of mgco3 and mnco3 in relation to the younger maškara siderite-barite-tetrahedrite ore deposit in the mbsm. obviously siderite-ankerite generation in the mačje jame deposit represents the earlier generation of iron carbonates in the mbsmts generated under higher p-t conditions (350-400°c and 1.5 kpa) (plate i, photos 1, 4, 5). albite (* content: 5.7 wt %), develops as single crystals, twins or polysynthetic crystals: 0.5 to 1 mm long, even 3 to 4 mm in druses. greater albite crystals occlude fragments or crystals of older carbonates, magnetite and ti-oxides. albite is very irregularly distributed in the ore. quartz i (*, 5.7 wt %) is very coarse-grained, cataclased and optically anomalous. quartz is mostly concentrated along salbands. it is younger than carbonate minerals replacing their particular zones (plate i, photo 3). pneumatolytic-katathermal phase of mineralization this phase accounts for between 2 and 4 wt.% of the ore of the mačje jame deposit (table 1.). geologia croatica 67/2geologia croatica 150 plate i six photomicrographs of the mačje jame ore samples. legend: hm – haematite, sd – siderite, pb – galena, mg – magnetite, py – pyrite, q – quartz, as – arsenopyrite, tennantite, chc – chalcedony, sf – sphaterite, ch – chalcopyrite quartz ii (*) is coarse-grained, most often associated with arsenopyrite crystals. arsenopyrite (*, 1.8 wt %) has been found in the three ore samples which gave 2.70, 0.79 and 0.36 wt.% feass. it is most abundant within carbonate minerals and as single pyrite ii (*, 3.1 wt %) is partly or strongly oxidized. unoxidized relicts of pyrite of two ore samples gave 0.65 and 5.62 wt.%. many bigger crystals are cataclased and locally mylonitized. it is the most abundant sulphide mineral (plate i, photo 2). 1 2 3 4 5 6 ivan jurković and hazim hrvatović: geochemical characteristics and genesis of mačje jame and vranjski potok as-cu-bearing iron occurrences ... geologia croatica 151 crystals, and as aggregates 50-200 μm in diameter. arsenopyrite crystals are sometimes occluded and associated in the coeval quartz crystals and distinguished predominantly with idiomorphic (rhombic) forms (plate i, photos 3, 4). mesothermal-epithermal phase of mineralization during this phase some co, fe, as, sb, bi and pb sulphides and sulphosalts were formed. marmatite (*) (average content is 0.11 wt%) is the oldest mineral of this phase replaced by other younger minerals, particularly by boulangerite in the form of small irregular masses or as bands of needles or crystals characterized by rhombic sections. marmatite is distinguished by yellow-brownish, red-brownish and red internal reflections, which indicate sphalerite, rich in iron. it is visible to the naked eye and its content in the ore is 0.107 wt. % (plate i, photos 5, 6). chalcopyrite (*) (average content is 0.06 wt.%) and associated tennantite (*) (av. content is 0.086 wt.%) are the main copper minerals (plate i, photos 5, 6). enargite-luzonite (*) (average content is 0.005 wt.%) is a very rare mineral in the form of minute crystals some tens μm in diameter, most often occluded in chalcopyrite. it is partly lamellar in habit (luzonite). galena (*) (average content is < 0.018 wt.%) is associated with other sulphides, or it selectively replaces haematite. drusy epithermal-hydatogene mineralization phase small irregular cavities in the ore have their interior walls encrusted with small quartz iii crystals or with chalcedony showing relicts of primary colloid structure. using optical methods, the following drusy minerals were identified (plate i, photos 4, 6). chalcedony (*) (average content is < 0.1 wt%) is the main gangue mineral of this mineralization phase. small grains of chalcedony are often characterized by their radialconcentric structure. quartz iii (*) grown on the drusy walls has a bipyramidal-prismatic habit. boulangerite (*) (average contents in three different samples calculated from the trace element analyses are 0.029, 0.019, 0.012 wt.%). it predominantly occurs within chalcedony in the form of numerous small aggregates or as very dense needle bundles or particular needles marked by rhombic cross-sections. droplets of pinkish bismuth (*) (average content < 0.01 wt.%) are noticeable within boulangerite. locally, there is a single grain or densely arranged minute yellow-pinkish grains with higher relief than that of the boulangerite replacing it, probably of argyropyrite (x) or sternbergite (x) (average content < 0.005 wt.%), goldishyellow coloured and of higher reflection than boulangerite (plate i, photo 6). yellow sphalerite (*) (average content < 0.01 wt.%) mostly within chalcedony is distinguished by clearer internal reflection, preponderantly yellowish. it forms minute drops reminiscent of a colloid structure. marcasite (*) is associated with gel-pyrite indicating generation from older weathered pyrrhotite. hypergene mineralization during the oxidation phase of the mačje jame ore deposit, the main mineral that formed is goethite, whereas lepidocrocite is rare. covellite, chalcocite, malachite, azurite and sb (as) oxides are subordinate or occur as accessories. small masses of elemental silver (φ 100-150 μm) were observed in two polished sections of the ore. 3.1.2. minerals identified during this study minerals identified using the data of trace element analyses, ree analyses and detailed microscopic investigations are indicated with a small black dot (●) and probable minerals with the symbol (○) (see table 1a). cassiterite (●) (average content 0.024 wt%) was observed in some ore samples (polished sections) as microscopically fine masses, distinguished by high relief, and great hardness. it is dark-grey or pinkish, characterized by low reflectivity, clear anisotropy and white-light-dark brown internal reflection. trace element analysis indicate 189 and 151 ppm sn which equates to 0,024 and 0,019 wt.% sno2. the mačje jame ore deposit is the second cassiterite bearing locality in the mbsm, the first locality being vrtlasce several km east of the town of fojnica (jurković, 1956). wolframite (○) (average content 0.012 wt%) is a presumed mineral, because trace element analysis of one ore sample produced a high content of 71.6 ppm w. the second reason for this presumption is the discovery of wolframite in the main vein of the big čemernica quartz-antimonitesphalerite-veiny system (ramović, 1956). wolframite crystals in the čemernica ore deposit are visible to the naked eye and contain 74 wt.% wo3, 18 wt.% feo and 6.2 wt.% mno which corresponds to the mineral hibernite. gersdorffite (○) (average content 0.03 wt %) is also a presumed mineral in the mačje jame ore deposit. trace element analyses produced 182 ppm of co and 244.2 ppm of ni. the recalculation of these values gives 0.022 wt.% of coass (cobaltite), and 0.030 wt.% of niass (gersdorffite). their isomorphic arsenide (gersdorffite) is a typical pegmatitc-pneumatolytic high-temperature mineral (ramdohr, 1983). columbite-tantalite (○). (average content 0.012 wt%) heightened contents of nb (26.8 ppm) and ta (10.9 ppm) in the same ore sample indicate presumed minerals from the isomorphic pair columbite-tantalite. recalculation gives (fe, mn,nb0.711ta0.289)2o6 with the participation of 0.012 wt.%. the high presence of y (58.8, 70 and 90.4 ppm) and 129 ppm of ce (table 5a) proves formation of the mineral allanite (**), whereas the presence of 28.1 ppm of th indicates monazite. 3.1.3. microscopic investigation of ore samples from the vranjski potok deposit twelve mineralized rock samples marked by symbols bos1, 2, 3, 4, 5, 6, 9, 10, 11, 13, 15 and 25 were investigated under the ore microscope. the mining investigations were conducted recently (in 2013, table 1b) in the initial phase, and therefore the ore samples have been picked up only in geologia croatica 67/2geologia croatica 152 plate ii photos 2-6 are photomicrographs of the vranjski potok ore deposit. photo 1 is from mačje jame ore deposit. legend: hm – haematite, sd – siderite, pb – galena, mg – magnetite, py – pyrite, q – quartz, as – arsenopyrite, tennantite, chc – chalcedony, sf – sphaterite, ch – chalcopyrite, ag – silver, au – gold ement analyses anticipating a genetic type of ore deposits, were indicated by two small darkened triangles (). the polished sections of bos-1, 3, 4, 15 and 25 samples were taken from quartzose conglomeratic metasandstone composed of rounded or semirounded particles. in the bosthe oxidation zone of the vranjski potok deposit. all minerals are displayed in table 1b. minerals identified under the microscope during this study in 2013 are indicated by a small darkened triangle (), and their contents were calculated from the chemical analyses. minerals identified by trace el1 2 3 4 5 6 ivan jurković and hazim hrvatović: geochemical characteristics and genesis of mačje jame and vranjski potok as-cu-bearing iron occurrences ... geologia croatica 153 table 2: chemical analyses of two ore samples from the mačje jame ore deposit (table 2a) and five samples from the vranjski potok ore deposit (table 2b). mačje jame table 2a sample ma-ja ma-js chemical method mdl fus-icp fus-icp average analyte wt. % wt. % wt. % wt. % sio2 0.010 14.380 5.060 9.720 al2o3 0.010 2.320 0.180 1.250 fe2o3 0.010 27.240 39.990 33.610 feo 0.010 17.990 17.310 17.650 mno 0.001 2.050 2.670 2.360 mgo 0.010 4.350 3.630 3.990 cao 0.010 3.130 1.460 2.290 na2o 0.010 1.300 0.040 0.670 k2o 0.010 0.030 0.010 0.020 tio2 0.001 0.020 0.100 0.060 p2o5 0.010 <0.01 0.010 <0.01 as 5 ppm 1.290 0.360 0.830 loi 26.520 30.410 28.470 total 0.01 100.620 101.230 100.980 table 2 (a+b) vranjski potok table 2b sample mdl bos-9 bos-10 bos-12 bos-13 bos-15 average analyte wt. % wt. % wt. % wt. % wt. % wt. % wt. % sio2 0.010 69.000 41.000 61.000 50.000 78.000 59.800 al2o3 0.010 5.330 4.910 2.140 7.160 3.040 4.520 tio2 0.010 0.020 0.010 0.010 0.020 0.010 0.010 fe2o3 0.040 17.470 42.810 29.640 30.730 12.210 26.570 cao 0.010 0.030 0.030 0.520 0.040 <0.01 0.120 mgo 0.010 2.630 1.760 0.430 2.310 0.810 1.590 na2o 0.010 <0.01 0.004 0.020 0.005 0.005 0.010 k2o 0.010 0.024 0.060 0.080 0.120 0.070 0.070 mno 0.010 0.100 0.080 0.270 0.080 0.030 0.110 p2o5 0.010 0.030 0.120 0.160 0.130 0.030 0.090 s 0.170 0.080 0.170 0.180 1.510 0.420 h2o+ (gt) 1.970 4.840 3.350 3.470 1.380 3.000 h2o+ (kl) 3.550 3.280 1.420 4.780 2.030 3.010 total 0.010 99.728 99.809 99.220 99.034 99.137 99.320 25 sample microbrecciated and mylonitized particles of host rock are visible. polished sections of these ore samples studied here contain different colloform limonite structures (fe oxides and hydroxides). irregular relict patches of pyrite i and coarse-grained porous and strongly cataclased pyrite ii are also present. locally, small masses of chalcopyrite, rarely sphalerite and one very weathered copper mineral, associated with malachite and azurite, probably tetrahedrite, are observed. hollows in the rock are encrusted with fine layers of younger pyrite and fe-hydroxide. sample bos-25 contains partly metasandstone and partly micrograined quartz as the main gangue, coloured by iron oxides (plate ii, photos 1-6). the bos-2, 5, 6, 9, 10, 12 and 13 samples are composed only of ore with predominantly micrograined quartz (diameter in μm). many quartz grains contain occluded pyrite and micrograins or micromasses of elemental gold or electrum which is bright yellow or silver-yellowish in colour. pyrite, gold and silver occluded in quartz grains are not oxgeologia croatica 67/2geologia croatica 154 idised because they are totally isolated in quartz grains. younger pyrite ii and mica flakes often occur in the fine fractures and rarely on the short faults in the quartz gangue. fine encrustations of arsenic and antimony oxides formed by weathering of arsenopyrite, tetrahedrite and lead antimonides are also visible in the small masses of chalcopyrite and malachite. 3.2. chemical composition of the ore of both deposits 3.2.1. the chemical composition of the main components of the mačje jame deposit by recalculating the data of two samples (table 2a) on the minerals identified earlier by optical methods (jurko vić, 1956), a mineral composition model was obtained as displayed in table 3c. it is for the most part an iron carbonate deposit with different fe-mg-ca-mn carbonates and with subordinate iron oxides magnetite and haematite. almost 50% of the siderite has been oxidized to goethite and lepidocrocite. only pyrite i, ii (av. content 3.1 wt%) and arsenopyrite (max. value 2.7 wt%) are visible to the naked eye, all other numerous sulphides and sulphosalts are accessories (table 1). although pyrrhotite was not identified microscopically, the presence of typical “birds eye” structure of gelpyrite-marcasite indicates its formation. when we attempted to recalculate all tot/s (total sulphur) only on pyrite, we obtained a lack of sulphur. 3.2.2. chemical composition of the ore in the vranjski potok ore deposit quartz occurs partly as detrital particles of quartzose metasandstone, and partly as a chemically precipitated gan gue mineral (table 2b, table 2c). the quartz content is approximately calculated at 60.6 wt %. the main ore mineral is goethite, whereas lepidocrocite is markedly subordinate. in the oxidation zone of the vranjski potok ore deposit, the primary hypogene siderite is almost completely oxidized into goethite, whereas pyrite, magnetite and haematite are partly altered to goethite. the average calculated content of these minerals amounts to 26.8 wt% and varies between 13.6 and 47.7 wt%. minerals of the clay group. due to the minute available amounts of the elements ca, k and na, conversion into kaolinite was performed out of the three possible minerals (kaolinite, illite and montmorillonite).. the obtained values range between 5.04 and 17.41 wt. % (the average value is 10.09 wt. %). the average content of albite is low (0.6 wt. %), and it is unevenly distributed in the ore. the content of albite is probably greater in the primary zone. contents higher than 1 wt% were only observed for oxidized copper minerals: malachite, azurite, cuprite, cu–sulphate etc. table 2c shows that the values of cufes2 in the primary zone would range between 0.6 and > 2.9 wt. %. the calculated content of fe2o3 (12.2 up to 42.8 wt.%) belongs to the mineral goethite. the al2o3 (with 2.1, and 7.2 wt. %) is locked into the clay minerals. a high content of h2o+ (crystal water) between 1.4 and 4.8 wt% is linked to goethite, whereas 1.4 to 4.8 wt% of crystal water is attributed to clay minerals. 3.3. trace elements in the mačje jame and vranjski potok ore deposits 3.3.1. trace elemets in the mačje jame deposit trace element contents in the mačje jame deposit are displayed in table 3. the most characteristic trace element is as predominantly as the mineral arsenopyrite. the heightened contents of co (182 ppm) and ni (244 ppm) also indicate the presence of cobaltite and gersdorffite. high contents of sn (151 and 189 ppm) is evidence of cassiterite and 71.6 ppm of w suggests the probable presence of the mineral wolframite. the ore sample ma-js contains 26.8 ppm of nb and 10.9 ppm of ta, which probably reflects the presence of the mineral columbite. among non-ferrous metals, zn is the most abundant (989 and 220 ppm) occurring in the minerals marmatite, tetrahedrite and in yellow sphalerite, cu (20, 25 and 370 ppm) is a constituent of chalcopyrite, tetrahedrite, and enargiteluzonite. pb (419 ppm) with sb (74, 35 and 30 ppm) formed the mineral boulangerite and with bi (44 ppm) the mineral cosalite. it is very interesting to note the low contents of ag (< 1.6 ppm), au (0.029 ppm), hg (0.95 ppm) and se (2.5 ppm). jurković et al., 2010a, 2011 proved mutual (reciprocal) genetic interdependence among bi, ag, au, hg and se. these trace elements are trace elements in the oldest mbsm deposit (mačje jame). in the youngest mbsm ore deposits with hg-tetrahedrite as the main, almost the only ore mineral (maškara, trošnik, glumac), the very high values of these elements incontestably suggest two different mineralising fluids in terms of time and space (jurković et al., 2010a). 3.3.2. trace element contents in the vranjski potok deposit high values of sn (50 and 181 ppm) indicate relicts of the resistant hypogene cassiterite. likewise, the values of zr (average 57 ppm) prove the presence of the mineral zircon. the heightened contents of y (16 to 47 ppm) and of ce (avtable 3: main mineral components in the mačje jame and vranjski potok ore deposits. main mineral components in the mačje jame and vranjski potok ore deposits table 3 ore deposit mačje jame vranjski potok number of samples three five analyte wt. % wt. % quartz 5.665 − 60.573 − siderite 44.730 47.241 − − albite 5.680 5.999 0.566 1.435 pyrite i, ii 3.090 3.264 − − arsenopyrite 1.814 1.916 0.018 0.046 chalcopyrite 0.058 0.062 >1.979 >5.019 clay mineral trace trace 10.093 25.596 goethite+fe3o4 + fe2o3 39.315 41.520 26.766 67.879 total 100.352 100.002 99.995 99.975 ivan jurković and hazim hrvatović: geochemical characteristics and genesis of mačje jame and vranjski potok as-cu-bearing iron occurrences ... geologia croatica 155 erage 77 ppm, table 6b) suggest relicts of the mineral allanite. in the bos-13 sample, 22.8 ppm of nb is presumed to represent relicts of niobite or columbite. the obtained values of co (83 ppm) and of as (558 ppm) in the bos-12 sample presume the relicts of hypogene cobaltite and arsenopyrite (tables 5a and 5b). in vranjski potok, the third hydrothermal phase is two to three times (see table 3) better developed than in the mačje jame deposit (table 4 and tables 5a and 5b), which indicates a stronger late variscan overprint. cu is the predominant trace element with contents of 0.19, 0.44, 0.48, > 1.0 wt%. the dominant copper minerals in the oxidation zone are malachite, azurite, cuprite, tenorite, cu-sulphates, chrysocolla. the element pb with the average values of 422 ppm occurs as cerussite and anglesite. 3.4. rare earth elements 3.4.1. ree contents in the mačje jame ore deposit three analyzed ore samples gave completely different σ ree values (tables 7a and 7b). the sample ma-js is characterized by an exceptionally high σ ree content of 353 ppm. la participates with 57 ppm, ce with 129 ppm and nd with 44 ppm (table 6a). heightened contents of y (70 ppm) and th (28 ppm) in the same sample prove the presence of allanite and monazite as accessory minerals. unusually elevated values of pr, gd, dy, er and yb reflect probably other, not yet identified lanthanide accessory minerals. the sample ma-sp is distinguished by a negative slope of the σ lree/ σ hree by the lowered negative eu-anoma ly, redoubled positive ce anomaly and negative la/smn and la/ybn fractionation factors (fig 3). 3.4.2. ree contents in the vranjski potok ore deposit five analyzed ore samples (table 6b) gave very different ree contents. the bos-10 and bos-13 samples have 275 ppm, bos-12 175 ppm, bos-09 122 ppm and bos-15 68 ppm. the main cause for this difference is the share of sandstone as the mother rock in the analyzed sample and the intensity of overprint. despite this, the majority of ree parameters, with the exception of bos-12, are roughly equal (table 7b). the eu-anomaly is negative, whereas the ce anomaly is positive. all three fractionation factors are positive, particularly the slope of the (la/ybn) curve. these five samples were affected by late variscan overprints, particularly the bos-12 (table 6b), and then bos15 and bos-10. the bos-12 sample contains > 1.0 wt.% of cu (> 2.9 wt% of cufes2), then > 0.2 wt% of bi (as cosalite and as bi), 74 ppm of se, 7.2 ppm hg, 178 ppm sb, 471 ppm of pb, 172 ppm of zn. the occurrence of bi, se, and hg is regularly associated with the presence of ag (32 ppm) and au (381 ppb). the average content of lanthanides in 5 ore samples from the vranjski potok deposit amounts to 183 ppm, ranging between 68 and 275 ppm (table 6b). three lanthanides (la, ce and nd) stand out among other lanthanides in terms of their content. lanthanum is present with an average value table 4: trace element contents in the mačje jame ore deposit ba-y group and mo-se group. trace element contents in the mačje jame ore deposit table 4 sample ma-ja ma-js ma-jp trace elements ma-ja ma-js ma-jp anal. method fus-mus fus-mus 4b method fus-mus fus-mus idx mdl mdl mdl mdl analyte ppm ppm ppm ppm ppm analyte ppm ppm ppm ppm ppm ba 3.00 7.00 6.00 1.00 31.00 mo 2.00 <2.00 <2.00 0.10 3.700 be 1.00 <1.00 <1.00 1.00 <1.00 cu 10.00 20.00 370.90 0.10 25.100 co 1.00 31.00 20.00 0.20 182.00 pb 5.00 6.00 <5.00 0.10 418.500 cs 0.10 0.10 0.20 0.10 0.10 zn 30.00 220.00 <30.00 1.00 989.000 ga 1.00 3.00 4.00 0.50 2.40 ni 20.00 40.00 30.00 0.10 244.200 hf 0.10 <1.00 8.10 0.10 <0.10 as 5.00 1.29 wt% 0.36 wt% 0.50 see table 2a nb 0.20 1.00 26.80 0.10 4.90 cd n.a. n.a. 0.10 1.800 rb 1.00 2.00 2.00 0.10 1.30 sb 0.20 74.40 34.60 0.10 30.200 sn 1.00 4.00 189.00 1.00 151.00 bi 0.10 1.80 0.60 0.10 43.700 sr 2.00 58.00 9.00 0.50 11.90 ag 0.50 <0.50 <0.50 0.10 3.900 ta 0.01 <0.01 10.90 0.10 <0.10 au* n.a. n.a. 0.50 29.20* th 0.05 0.27 28.10 0.20 0.30 hgx n.a. n.a. 0.01 0.95x u 0.01 1.66 4.57 0.10 1.90 tlx 0.05 <0.05 0.07 0.10 0.10x v 5.00 51.00 101.00 8.00 127.00 sex n.a. n.a. 0.50 2.50x w 0.50 2.20 71.60 0.50 3.70 ge 0.50 1.70 1.30 n.a. zr 1.00 <1.00 269.00 0.10 2.70 scx 1.00 11.00 16.00 n.a. y 0.50 58.80 70.00 0.10 90.40 cr 20.00 <20.00 <20.00 n.a. total 220.03 820.27 610.60 total 374.90 453.47 1763.65 geologia croatica 67/2geologia croatica 156 of 40 ppm, ce with 77 ppm, and nd with 32 ppm. the avera ge value of all three lanthanides (la + ce + nd) is 146 ppm, which accounts for 82 wt. % of the content of all 14 lanthanides in the vranjski potok deposit. in view of the fact that metarhyolite and its protolith contain the same or very similar ree and la, ce and nd values as the predominant ree elements, it was concluded that the metamorphogenic fluids generated in the table 5: content of trace elements in the vranjski potok deposit ba-y group (table 5a) and mo-se group (table 5b). trace elements (ba-y) in the vranjski potok deposit table 5a sample mdl bos-09 bos-10 bos-12 bos-13 bos-15 anal.method 4b 4b 4b 4b 4b 4b analyte ppm ppm ppm ppm ppm ppm ba 1.0 48.00 172.00 165.00 360.00 605.00 be 1.0 <1.00 <1.00 <1.00 1.00 <1.00 co 0.2 14.90 17.50 83.20 11.80 5.80 cs 0.1 0.40 1.80 0.50 3.80 1.40 ga 0.5 13.00 15.60 5.10 25.40 10.30 hf 0.1 1.70 1.70 0.10 2.30 2.00 nb 0.1 7.50 9.70 3.10 22.80 7.70 rb 0.1 5.80 44.90 13.80 93.60 44.80 sn 1.0 49.00 54.00 181.00 28.00 16.00 sr 0.5 8.00 12.30 11.20 13.10 8.40 ta 0.1 0.60 0.80 0.10 1.30 0.60 th 0.2 6.60 10.40 0.80 17.00 5.50 u 0.1 1.10 2.80 1.20 3.00 0.80 v 8.0 39.00 55.00 13.00 83.00 38.00 w 0.5 <0.50 3.40 <0.50 3.90 0.90 zr 0.1 60.50 54.70 5.30 85.60 56.80 y 0.1 15.20 25.80 46.70 26.30 7.40 total 271.30 482.40 530.10 781.90 811.40 trace elements (mo-se) in the vranjski potok deposit table 5b sample mdl bos-09 bos-10 bos-12 bos-13 bos-15 anal.method 4b 4b 4b 4b 4b 4b analyte ppm ppm ppm ppm ppm ppm mo 0.10 4.90 2.50 2.20 1.00 0.60 cu 0.10 1.954.00 4.807.00 >10.000.00 4.417.00 >10.000.00 pb 0.10 190.40 562.30 471.40 821.40 63.30 zn 1.00 155.00 407.00 172.00 84.00 57.00 ni 0.10 3.00 7.10 21.90 4.30 2.00 as 0.50 25.90 19.80 551.17 24.70 <0.50 cd 0.10 <0.10 0.20 0.90 0.20 0.20 sb 0.10 2.10 4.70 178.40 22.10 0.80 bi 0.10 125.80 81.00 >2.000.00 63.40 14.80 ag 0.10 1.90 15.30 32.40 1.20 8.70 au* (ppb) 0.50 240.50 181.00 380.80 89.90 772.10 hgx 0.01 0.98 0.71 7.15 0.31 2.69 tlx 0.10 <0.10 <0.10 <0.10 <0.10 <0.10 sex 0.50 9.60 10.50 74.00 19.50 11.80 total 2.714.08 6.099.11 >13.892.30 5.549.01 >10.934.00 ivan jurković and hazim hrvatović: geochemical characteristics and genesis of mačje jame and vranjski potok as-cu-bearing iron occurrences ... geologia croatica 157 s-granite magma and their pre-palaeozoic and lower palaeozoic protoliths, might be a source of mineralizing fluids for the generation of the mačje jame and vranjski potok deposits. 3.4.3. comparison of the ree contents between the mačje jame and vranjski potok ore deposits, and the metarhyolites and keratophyres from bu sovačafojnica-kreševo region the range of ree contents between the ore samples and magmatic rock samples is displayed in table 8. the range of ree content values range from 158 to 197 ppm (average 180 ppm) for 5 samples of rhyolite and metarhyolite from the fojnica-kiseljak-kreševo region. these 5 samples have the following average content of dominant elements: la 35 ppm, ce 76 ppm and nd 33 ppm. furthermore, the 3 rhyolite samples from the šebešićkozica-kruščica (busovača) region show values of between 205 to 214 ppm (average 209 ppm) with the following dominant values: la 43 ppm, ce 88 ppm and nd 35 ppm. five samples from the vranjski potok ore deposit produced values between 68 and 275 ppm, with an average value of 183 table 6: ree content of the samples from the mačje jame deposit (table 6a) and from the vranjski potok deposit (table 6b). ree content in the mačje jame deposit table 6a sample ma-ja ma-js ma-jp chemical method mdl fus-mus fus-mus mdl 4b average analyte ppm ppm ppm ppm ppm ppm la 0.050 9.62 56.60 0.1 2.90 23.04 ce 0.050 20.10 129.00 0.1 6.50 51.87 pr 0.010 2.48 14.20 0.02 0.95 5.88 nd 0.050 9.21 43.70 0.3 4.80 19.24 sm 0.010 3.27 11.70 0.05 2.64 5.87 eu 0.005 1.28 4.89 0.02 1.98 2.72 gd 0.010 4.50 13.70 0.05 5.23 7.81 tb 0.010 1.16 3.41 0.01 1.49 2.02 dy 0.010 8.90 25.60 0.05 11.43 15.31 ho 0.010 2.06 5.73 0.02 3.03 3.61 er 0.010 6.93 18.60 0.03 9.87 11.80 tm 0.005 1.18 2.98 0.01 1.58 1.91 yb 0.010 8.23 19.90 0.05 9.85 12.66 lu 0.002 1.21 2.80 0.01 1.46 1.82 total 80.13 352.81 63.71 165.55 ree contents in the vranjski potok ore deposit table 6b sample mdl bos-09 bos-10 bos-12 bos-13 bos-15 average analyte ppm ppm ppm ppm ppm ppm ppm la 0.10 30.00 57.60 39.80 60.00 13.60 40.02 ce 0.10 56.30 114.40 68.30 117.10 29.70 77.16 pr 0.02 5.47 13.67 8.20 13.42 3.41 8.83 nd 0.30 17.10 51.10 29.60 50.90 12.90 32.32 sm 0.05 2.82 10.22 4.47 9.80 2.29 5.92 eu 0.02 0.87 4.56 1.77 3.07 0.92 2.24 gd 0.05 2.36 8.61 5.59 8.37 1.80 5.35 tb 0.01 0.43 1.33 1.08 1.12 0.27 0.85 dy 0.05 2.43 6.31 6.63 5.09 1.43 4.38 ho 0.02 0.55 1.03 1.41 0.91 0.23 0.83 er 0.03 1.63 2.63 3.75 2.39 0.66 2.21 tm 0.01 0.25 0.40 0.53 0.39 0.10 0.33 yb 0.05 1.51 2.41 3.19 2.35 0.66 2.02 lu 0.01 0.23 0.36 0.43 0.35 0.09 0.29 total 121.95 274.63 174.75 275.26 68.06 182.75 geologia croatica 67/2geologia croatica 158 ppm. the average values for la, ce and nd were 40 ppm, 77 ppm and 32 ppm, respectively. 4. genesis of the iron deposits mačje jame and vranjski potok the first mineralization phase of the mačje jame deposit (> 90-95 wt. %) is composed of 44.7 wt. % of fe (ca, mg, mn)co3 carbonates, 39.3 wt. % of magnetite, haematite and goethite, 5.7 wt. % of albite, 3.1 wt. % of pyrite, 1.8 wt. % arsenopyrite, 0.06 wt. % chalcopyrite, 0.05 wt. % of ree and 0.42 wt. % are trace elements. siderite as the predominant ore mineral is composed of 62.5 wt. % feco3, 8.8 wt. % caco3, 19.3 wt. % mgco3 and of 9.4 wt. % mnco3 (table 9b) indicating formation under elevated pt conditions (350–400°c and 3.5 kbars), majer et al., (1991). during the very subordinately developed pegmatiticpneumatolytic phase, numerous scarce or accessory minerals were formed: quartz ii as gangue and as ore minerals, arsenopyrite (average content 1.81 wt. %), pyrrhotite, cassiterite (0.024. wt %), wolframite (0.012 wt. %), cobaltite (0.02 wt. %), gersdorffite (0.03 wt. %). one of the three analysed mačje jame samples contained elevated contents of nb (26.8 ppm) and ta (10.9 ppm), indicating the presence of the mineral columbite (0.012 wt. %). table 7: ree parameters in the ore samples from the mačje jame deposit (table 7a) and from the vranjski potok deposit. ree parameters in the ore samples from the mačje jame deposit table 7a sample ma-ja ma-js ma-jp average mineral sd sd sd σree 80.13 352.81 63.71 165.55 σlree 44.68 255.20 17.79 105.89 σhree 32.96 89.92 42.48 55.12 σlree σhree 1.36 2.86 0.42 1.55 eu/eu* 0.34 0.39 0.53 0.42 ce/ce* 4.12 4.55 10.79 6.49 (la/sm)n 1.90 3.12 0.71 1.91 (gd/yb)n 0.45 0.57 0.44 0.49 (la/yb)n 0.84 2.04 0.21 1.03 ree parameters in the vranjski potok ore deposit table 7b sample bos-09 bos-10 bos-12 bos-13 bos-15 average σree 121.95 274.63 174.75 275.26 68.06 36.83 σlree 111.69 246.99 150.37 251.22 61.90 148.56 σhree 9.16 22.72 22.18 20.62 5.15 13.85 σlree σhree 12.19 10.87 6.78 12.18 12.02 10.75 eu/eu* 0.34 0.49 0.35 0.34 0.45 0.40 ce/ce* 4.40 4.08 3.78 4.13 4.36 3.95 (la/sm)n 6.87 3.64 5.75 3.95 3.83 4.23 (gd/yb)n 1.29 2.96 1.45 2.95 2.26 2.17 (la/yb)n 14.26 17.14 8.95 18.32 14.79 14.55 table 8: comparison of the ree contents between rhyolite-keratophyres and ore samples from the mačje jame and vranjski potok ore deposit. localities rocks and ore samples kreševo rhyolite kreševo keratophyre busovača metarhyolite busovača metarhyolite mačje jame vranjski potok analyte ppm ppm ppm ppm ppm ppm 1 la 34.60 16.60 43.00 22.30 33.10 40.00 2 ce 75.70 37.70 87.00 43.90 74.60 77.20 3 nd 32.70 17.80 43.50 16.30 30.00 32.30 4 la+ce+nd 143.00 72.10 174.20 82.50 137.70 149.50 5 σree 179.60 95.40 209.30 105.30 216.80 187.90 6 la+ce+nd/ σree 0.80 0.76 0.83 0.78 0.60 0.84 ivan jurković and hazim hrvatović: geochemical characteristics and genesis of mačje jame and vranjski potok as-cu-bearing iron occurrences ... geologia croatica 159 the first and second mineralization phases were most-probably formed during the middle carboniferous (visean-moscovian) derived from metamorphogenic fluid generated from s-granitoid magma and its protoliths. the third, hydrothermal phase, (very poorly developed, 1-4 wt. %) is characterized by the following minerals: marmatite, tetrahedrite, chalcopyrite, boulangerite, galena, cosalite, yellow sphalerite, enargite–luzonite, sternbergite, elemental bismuth, “birds-eye” structures of gel-pyrite-marcasite, traces of silver (4 ppm) and traces of gold (29.2 ppb). gangue minerals are quartz iii, chalcedony, and rarely calcite. the third mineralization phase of both deposits is characterized by trace elements which are genetically the most important for the youngest deposits in the mbsm: siderite-barite-hg tetrahedrite deposits. these elements are bi, se, hg, ag and au, built up in the tetrahedrite lattice as the main constituents. these five elements reached mačje jame and vranjski potok ore deposits as an overprint of post-variscan permian or permo-triassic magmatic activity (jurković et al., 2011). in the jezero-jajce part of the mbsm, there is an old, abandoned austro-hungarian copper mine at sinjakovo, with the ores in the carboniferous sediments associated with numerous contemporaneous rhyolite sills and veins. gangue minerals consist of siderite, ankerite, ferrodolomite, with chalcopyrite as the main ore mineral (vasiljević, 1972). a very similar paragenesis occurs in gemericum (slovakia), in the root zone of siderite veins at the boundary between greenschist and amphibolite facies, as reported by radvanec & bartalsky (1987), bartalsky (1991) and bartalsky and radvanec (1993). because majer and garašić (2001) expressed their doubt about the juvenile origin of the rhyolite magma from vranica mountain, jurković et al., (2010a) investigated the 87sr/86sr isotopic ratios in the rhyolite sample from this magma. they obtained the first, extremely high result of strontium isotope ratio of 0.776995 which indicates the previously suggested crustal origin. during further scientific investigation, they presented an additional four 87sr/86sr isotopic ratios obtained from the rhyolite samples collected from outcrops in the kruščica and kozica river valleys and in the mountains of ščit (busovača) and međuvršje (kreše vo). the results were lower than in the first sample from vranica mountain, but still high. finally, the last sample taken at the end of 2013 was collected from four separate rhyolite outcrops in the jezernica river valley. these four samples have been combined and prepared for determination of their 87sr/86sr isotopic ratio. the amazingly high result of 0.808079, (greater than the first value), proves that the whole vranica mountain rhyolite block is one unique laccolite of the same granitic magma. these results convinced us that the metamorphogenic fluids derived from an s-granitoid magma and their protoliths were the most probable source for the origin of the mačje jame and vranjski potok ore deposits. recently, garašić et al., (manuscript) performed detailed chemical and geochemical analyses of numerous rhyolite, metarhyolite, keratophyre and quartz keratophyre samples from the busovača-fojnica-kiseljak-kreševo areas. garašić et al. (manuscript, 2014) also accepted our suggestion to use the discrimination diagrams for the mbsm granite classification in accordance with their tectonic setting. therefore, they continued to work on this problem and the results should be published very soon in a new scientific article. similar opinions with respect to variscan granitic rocks in the moldanubian, and in the eastern and southern alps were published by neubauer (1988) and finger and steyrer (1990). figure 3: plot of rare-earth elements normalized to c1 chondrites (sun & mcdonough, 1989). ma–mačje jame deposit; bos–vranjski potok deposit. geologia croatica 67/2geologia croatica 160 5. conclusion the mačje jame and vranjski potok iron ore occurrences situated in the north-eastern part of the mbsm, are the earliest postorogenic ore deposits in the mbsm. they formed from the metamorphogenic fluids generated from s-granitoid magma and its protoliths for the most part during the period between the visean-moscovian stages partly even earlier. both ore deposits are located in the biotite-chlorite zone, the transition zone between amphibolite and greenschist metamorphic zones. in the late-variscan time (290-260 ma and in the upper permian-lower triassic (260-240 ma) time), mačje jame and vranj ski potok were caught by a younger overprint which brought along bi, se, hg, ag, au elements as well as non-ferrous metals cu, pb, zn. a very similar paragenesis of siderite veins is present in the gemericum (slovakia), reported by radvanec et al. (2004) who consider that this deposit represents the oldest ore occurrence in the gemericum palaeozoic complex. references bartalsky, b. (1991): results of the study of vein mineralization in the rožnava ore field – evidence for the metamorphic – hydrothermal genetic model.– unpublished csc thesis. geological survey of slovak republic, spišska nova ves (in slovak). bartalsky, b. & radvanec, m. (1993): relation between minerals of the fe-zn-as-s and fe-ti-mn-o element association in conditions of regional metamorphism, rožnava – turecka ore field, spiš-gemer ore mts., eastern slovakia.– mineralia slovaca 25, 437–450. finger, f. & steyrer, m. p. (1990): i-type granitoids as indicators of a late palaezoic convergent ocean-continent margin along the southern flank of the central european variscan orogen.– geology, 18, 1207–1210. garašić, v., jurković, i., lugović, b.(†) & hrvatović, h. (2014): petrogenesis of palaeozoic metarhyolites from mid-bosnian schist mountain.– unpublished manuscript. hrvatović, h. (1996): structural and facies analyses of parts of the mid-bosnian schist mountains (in bosnian).– unpublished ph. d. thesis, tuzla university, 112 p. hrvatović, h. (1999): geological guide through bosnia and herzegovina. monography (in bosnian).– geološki glasnik, 24, sarajevo, 203 p. hrvatović, h. (2006): geological guidebook through bosnia and her zegovina.– geological survey of federation bosnia and herzegovina, sarajevo, 172 p. jovanović, r., mojičević, m., tokić, s. & rokić, lj. (1978): osnovna geološka karta sfrj 1:100000, tumač za list sarajevo [basic geological map of sfry 1:100000, geology of sarajevo sheet – in serbian].– savezni geološki zavod, beograd, 52 p. jurković, i. & majer, v. (1954): rioliti (kremeni porfiri) vranice planine i albitski riolit sinjakova u srednjobosanskom rudogorju [rhyolithe (quartzporphyre) of vranica mountain and albite rhyolithe (quartzkeratophyre) of sinjakovo in mid-bosnian ore mountains – in croatian].– vesnik zavoda za geološka i geofizička istraživanja rn srbije, beograd, knjiga 11, 207–233. jurković, i. (1956): mineralne parageneze srednjobosanskog rudogorja s osobitim osvrtom na tetraedrite [mineral parageneses of the mid-bosnian ore mountains with special respect to tetrahedrites – in croatian].– phd thesis, university of zagreb, 306 p. jurković, i. (1958): kasiterit, stamin i molibdenit u rudnoj pojavi vrtlasce kod klisa [cassiterite, stannite and molybdenite from the occurrence vrtlasce at klisac].– geološki glasnik, sarajevo, 4, 304– 320. jurković, i., garašić, v. & hrvatović, h. (2010a): geochemical characteristics of the barite occurrences in the palaeozoic complex of the southeastern bosnia and their relationship to the barite deposits of the mid-bosnian schists mountains.– geol. croat., 63/2, 241–258. jurković, b. i., garašić, v. & jurković, m. i. (2011): cobalt, nickel, tungsten, cadmium, silver and gold-bearing mercurian tetrahedrite from the saski rad barite – siderite deposit in the midbosnian schist mts.– geol. croat., 64/3, 223–237. karamata, s. & krstić, b. (1996): terranes of serbia and neighbouring areas.– in: knežević, djordjević, v. & krstić, b. (eds): terranes of serbia, barex. belgrade, 25–40. table 9: carbon, oxygen and sulphur isotopic values of siderite and pyrite minerals (table 9a). isomorphic composition of the different siderite samples in the mbsmts (table 9b). carbon, oxygen and sulphur isotopic values of siderite and pyrite in the mačje jame deposit table 9a mineral sample δ13cpdb δ18ovsmow δ34svcdt sd ma-ja –9.5 18.0 sd ma-js –10.1 17.2 py ma-jp +5.3‰ isomorphic composition of the different siderite samples in the mbsmts table 9b ore deposit mačje jame vranjski potok vrtlasce fojnica trošnik fojnica maškara – saski rad bakovići – čemernica analyte wt. %. wt. %. wt. %. wt. %. wt. %. wt. %. feco3 62.53 70.13 71.75 74.39 81.23 86.66 caco3 8.78 3.55 15.75 12.89 9.52 1.43 mgco3 19.30 24.13 10.30 10.03 6.59 2.50 mnco3 9.40 2.20 2.02 2.69 2.66 10.10 total 100.01 100.00 99.82 100.00 100.00 100.69 ivan jurković and hazim hrvatović: geochemical characteristics and genesis of mačje jame and vranjski potok as-cu-bearing iron occurrences ... geologia croatica 161 katzer, f. (1905): über die quartzporphyre der vranica planina in bosnien und über einen fund von rillensteinen.– zentralblatt f. min. etc., no 18, 366 p. katzer, f. (1906): geologische übersichtskarte von bosnien-herzegovina. i. 1:200000 seckstelblatt sarajevo. katzer, f. (1910): die eisenerzlagerstätten bosniens und der herzegovina.–wien. katzer, f. (1924): geologie von bosnien und herzegovina.– sarajevo, 527 p. majer, v., lugović, b. and trubelja, f. (1991): metamorphism of the midbosnian schist mountains: an preliminary investigation (in croatian).– radovi anubih, sarajevo, 87/13, 141–158. majer, v. & garašić, v. (2001): metarioliti vranice planine u paleozoiku središnje bosne [metarhyolites of vranica mountains in palaeozoic of middle bosnia – in croatian].– rudarsko-geološko-naftni zbornik, 13, 9–14. matté, p. (1984): tectonics and plate tectonic model for the variscan belt of europe.– tectonophysics, 120, 329–374. mitchell, a.h.g., finger, f., steyrer, h.p. & neubauer, f. (1991): comments and replies on „i-type granitoids as indicators of a late paleozoic convergent ocean-continent margin along the southern flank of the central european variscan orogen.– geology, 19/12. mudrenović, v., stojanović-kuzenko, s. & pajić, v. (1969): razvoj silura i devona u području jezera kod jajca (zapadna bosna) [development of silurian and devonian in the jezero area near jajce – in bosnian].– iii. simpozij dinarske asocijacije, zagreb, 133–146. neubauer, f. (1988): the variscan orogeny in the austroalpine and southalpine domains of the eastern alps.– schweizerische mineralogische und petrographische mitteilungen, 68, 339–349. palinkaš, l., majer, v., balogh, k., bermanec, v. & jurko vić, i. (1996): geochronometry and termochronometry of the metamorphism in the inner dinarides, mbsm.– annual meeting of unesco igcp project no 356, sofia 1996. pamić, j. & jurković, i. (2002): palaeozoic tectonostratigraphic units of the northwest and central dinarides and the adjoining south tisia.– international journal of earth sciences, 91, 538–554. pamić, j., balogh, k., hrvatović, h., balen, d., jurković, i. & palinkaš, l. (2004): k-ar and ar-ar dating of the palaeozoic metamorphic complex from the mid-bosnian schist mts., central dinarides, bosnia and herzegovina.– mineralogy and petrology, 82, 65–79. radvanec, m. & bartalsky, b. (1987): geochemical zonality of stratiform sulfidic mineralization in the area smolnik-štos-medzev.– mineralia slovaca, 19, 443–445. radvanec, m., grecula, p. & žak, k. (2004): siderite minerali zation of the gemericum superunit (western carpathians, slovakia) review and revised genetic model.– ore geology reviews, 24, 267–298. ramdohr, p. (1983): the ore minerals and their intergrowths, 2nd edition, vol. 1 and 2.– pergamen press, berlin,1207 p. ramović, m. (1956): volframit iz čemernice kod fojnice [volframite from čemernica near fojnica – in bosnian].– tehnika, 11. sofilj, j., živanović, m. & pamić, j. (1980): osnovna geološka karta sfrj 1:100000, tumač za list prozor [basic geological map of sfry 1 : 100000, geology of the prozor sheet – in serbian].– savezni geološki zavod, beograd. trubelja, f. (1978): paleozojski magmatiti srednjobosanskih škriljavih planina [palaeozoic magmatic rocks of the mid-bosnian schist mountains – in bosnian].– in: geology of bosnia and herzegovina, part iv.: magmatism and metallogeny, sarajevo, 11–18. vasiljević, r. (1972): geologija i metalogenija paleozoika u području jezera i sinjakova kod jajca [geology and metallogeny of palaeozoic in the jezero and sinjakovo near jajce – in serbian].– unpubl. phd thesis, university of zagreb, 128 p. vujnović, l. (1981): osnovna geološka karta sfrj 1:100000, tumač za list bugojno [basic geological map of sfry 1:100000, geology of the bugojno sheet – in serbian ].– savezni geološki zavod, beograd, 56 p. živanović, m. (1972): geološki sastav i tektonski sklop šire oblasti vranice u centralnoj bosni [geology and tectonics of the vranica mountain in the central bosnia – in serbian].– phd, university of beograd, geoinženjering sarajevo. živanović, m. & milivojević, r. (1975): osnovna geološka karta sfrj 1:100000, tumač za list zenica [basic geological map of sfry 1:100000, geology of the zenica sheet – in serbian ].– savezni geološki zavod, beograd. živanović, m. (1979): naslage centralno-bosanskog paleozoika (vra nica) [sediments of the central bosnian palaeozoic (vranica) – in serbian].– in: “geologija bosne i hercegovine”, knj. i. paleozojske naslage, sarajevo, 55–68. manuscript received december 01, 2013 revised manuscript accepted may 14, 2014 available online june 17, 2014 2017 | 70/2 | 71 | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 8th croatian-hungarian and 19th hungarian geomathematical congress doi: 10.4154/gc.2017.11 the university of szeged, used cluster analysis to define genetically similar lithological units. the goal of their study was, not only to form them into clusters, but also, to observe the distribution in the 3d modelled space. a group of authors from ina (in the oil industry), led by novak-zelenika, presented their investigation of the petrophysical characterisation and modelling of reservoirs by the application of deterministic and stochastic methods. the study showed that selection of the method for defining the spatial distribution of the petrophysical properties (deterministic and stohastic) has a significant influence on the applicability of the geological model in defining areas of high risk, and it also has an influence on dynamic modelling complexity. cvetković, from the faculty of mining, geology and petroleum engineering regarded possible mathematical applications for well log data correlation in an effort to reduce the subjectivity of the classical „motif observation” approach which indicated the usability of plotting trend curves of standard deviation values of well log data. an article covering the application of geomathematics to geological problems is that by koroncz et al. from the geochem and rag laboratories in hungary. in contrast to the three, previous works which handle the application of geomathematics on a larger scale, the problems highlighted here relate to the domain of petrophysical properties in a sample size dataset. the authors provided an approach for determining the petrophysical properties of shales for better definition of velocity propagation data for seismic depth migration and to show the correlation of porosity concerning effective stress value. in the final article, a group of authors from the faculty of mining, geology and petroleum engineering addressed the quality of potable water in the zagreb aquifer. kovač et al. applied multivariate statistical ana­ lyses to testing the relationships of water parameters and allocating them using cluster analysis. we hope that this selection of original scientific articles provides new understanding of the usefulness of geomathematical approaches and incites some of you to apply geomathematics to your area of expertise. marko cvetković, issue editor lidija galović, editor-in-chief dear colleagues, it is our pleasure to present to you a selection of papers from the croatian­hungarian conference held in may 2016 in trakošćan. geomathematics covers a wide range of mathematical applications in geosciences, ranging from simple data analysis to complex multivariate analysis, mapping algorithms, uncertainty ana­ lysis and neural networks. many regard geomathematics as a new discipline, which is quite far from the truth. in general, handling geological data in the modern world is fairly difficult without a certain amount of mathe­ matical knowledge. this is extremely evident when geoscientists are handling large numbers of data for interpretation, regardless of whether that data was acquired by state of the art seismic investigations or in the form of a large number of samples obtained by a geologist in the field with a hammer. most of us use geo­ mathematics in one way or another at some point in our research. for popularization of geomathematics amongst geoscientists, a geomathematical section was formed within the croatian geological society in 2007. the 1st croatian-hungarian geomathematical congress was organized shortly after in 2008, alongside the 12th hungarian geomathematical congress which was already established as a traditional one. for the first few years, this meeting was organised solely in hungary until the 4th croatian-hungarian geomathematical and 15th hungarian geomathematical congress were held in opatija in 2014. two years later, opatija was the location again, and four years later in trakošćan. this affirms the conference as a traditional one which is organised every other year in croatia under the croatian geological society, with the geomathematical section as the main organizer. this special issue comprises several scientific papers from various fields of geology (petroleum geology, petrophysics, sedi­ mentology and hydrogeology) and with different applications of geomathematics presented with a goal to raise interest in such applications to both seasoned geologists and young specialists. in the case of possible characterization of deep water clastic depositional systems in the pannonian basin, horváth et al. from geologia croatica 45 1524 2 pl. zagreb 1992 udc 551.762.23:561.26 (497.13) scietific paper two new species of calcareous algae (dasycladaceae) from the upper dogger of southern dalmatia (croatia) branko sokać key words: calcareous algae, dasycladaceae, upper dogger, adriatic carbonate platform, croatia two new species of calcareous algae (dasycladaceae) are described. one sa/ping opore/la croatica n. sp. -is characterized by a clyindrical skeleton and undivided, phloiophorous to partly vesiculiferous rarnifications, arranged in whorls. the other speciesuragiella rag us ina n.sp. also has a cylindrical thallus and ramifications arranged in whorls. the shape of the ramifications , however, v aries from nodular or tubercular to atypically pyriform and more rarely, to the uragiella­ type. the ramifications are()ften deformed, which is particulary visible in more dis tal tangential sections. both species are found in the same sample which belongs , chronostratigraphically, to the upper dogger. family dasycladaceae k01zing, 1843 genus salpingoporella pia in trauth, 1918 salpingoporella croatica n. sp. pl. i; pl. il, figs. 1-3. 1970. pianella? sp.-radoičić, p.100, pl.l, figs.3-4 . origin of the name: after my native country ,croatia, to which this species is dedicated. type locality: outcrops of upper dogger limes tone in the road cut about 2 km s from osojnik in the direction of grebe i village; en viro ns of dubrovnik, south dal matia, croatia. the greenwich coordinates of the type locality for both species are 18.4'40"e and 42.43'29"n. type stratum.: light brown, well-bedded, foraminiferal­ -algal grainstone/packstone, representing reworked and partly washed out lagoonal sediments belonging to the upper part of the dogger. holotype: tangential-longitudinal section in thin­ section 0-79/16, depicted in pl. i, fig. 2. the original material is stored at the institute of geology, zagreb. the available material consists of about 150 thin sections, which contain numerous sections of s. croatica and somewhat less numerous sections of s. ragusina. diagnosis: salpingoporella croatica n. sp. has a cylindrical skeleton, characterized by undivided ramifications which show a tendency toward distal swelling, which makes them more similar to the vesiculiferous than to the phloiophorous type, so that a-stalk and a di stal swelling can,be partly: distinguished. ... the ramifications are arranged into clear whorls which are set rather apart from each other. near to the central institute of geology, sachsova 2, p.p. 213 , 41000 zagreb, croatia ključne riječi: vapnenačke alge (dasycladaceae), gornji doger, jadranska karbonatna platforma, hrvatska opisane su dvije nove vapnenačke alge (dasycladaceae), od kojih jedna, cilindričnog skeleta i pršljenastog položaja nepodjeljenih ogranaka floiofomog do nepotpuno formiranog vesikulifemog tipa, pripada rodu salpingoporella (salpingoporella croatica n. sp.). druga vrsta također cilindričnog skeleta i pršljenastog rasporeda nepodjeljenih ogranaka, odlikuje se njihovim varijabilnim oblikom, koji može biti gomoljičast, netipično piriforman ili, rijetko uragielskog tipa. ogranci su često deformirani, što je posebno vidljivo u perifernom tangencijalnom presjeku. s ovim karakteristikama uvrštena je u rod uragiella i opisana kao vrsta uragiella ragusina n.sp. obje vrste potječu iz istog uzorka koji kronostratigrafski pripada gornjem dogeru. cavity they are vertically aligned, whereas more distally they tend to assume an alternate arrangement. description: ln the available sections, the cylindrical calcareous skeleton consists of recrystallized calcite, and may sometimes be bent to various degrees. the destroying of the outer surface affected also the pores of the distal ends of the ramifications, resulting-as it is also the case in some other species of this genus in an indented con tour of the outer surface. the central cavity (or "main stem") is delineated by a clear and straight line, which indicates an even inner surface, perforated at the levels of whorls by tiny pore channels of the proximal parts of the ramifications. the axial cavity occupies 30-50% of the total diameter, in some cases even seemingly more, as a result of the destroyed peripberal part of the calcite skeleton. the ramifications are simple, undivided, and arranged into clearly differentiated whorls, which are set quite far apart from each other; this latter characteristic being not directly dependent upon the strong distal widening of the ramifications. part of sections with less eroded outer walls indicates that the original shape of the ramifications was the one with an uncompletely differentiated stem and a more clearly prqnounced ,đisl:fll swelling (pl. i, figs. 5, 9-jo; pl. ii, fig . 1.). generally speaking, this ramification shape may be spoken of as representing an intermediate form between a well developed phloiophorous and an uncompletely developed vesiculiferous type. apart of the available. sections seem to show that the ramifications do reach the outer surface but without producing any noticeable protrusions, or 16 protuberances, on it. in tangential sections, regardless of their depth, this shape of the ramifications results in circularly shaped pores whose diameter increases slightly in the first half of the ramification's length and more abruptly in the distal part. the arrangement of pores in successive whorls, with regard to each other, is not always the same in all parts. while in deeper tangential sections the pores appear to be more or less aligned into vertical rows (pl. i, fig. 3; pl. il, fig. 2), in more shallow, i. e. dis tal, parts a tendency. to an alternating arrangement can be discerned (pl. il, fig.l). dimensions in mm: maximum observed lenght of thallus (l) 3.02 outer thallus diameter (d) inner thallus diameter (d) maximum diameter of the ramifications (p) distance between the whorls (h) number of ramifications in a whor1 (w) 0 .34-0.92 0 .14-0.38 0.08-0.12 0.12-0.16 8-14 most frequent values 0.42-0.52 0.24-0.28 0.08-0.10 0.12-0.14 12 geologia croatica 45 as regards s. eta/lo ni and s. enayi, in spite of the general similarity and only slight differences in the outer and inner thallus diameters, s, croatica shows a larger variation range in both mentioned characters, and, accordingly, in the axial cavity volume, which in s. croatica varies from 30-50% of the outer thallus diameter. most evidently, the number of ramifications per whorls amounts to only 8-14 in s. croatica, whereas it is almost twice as much (about 20) in s. etalloni, and even as much as 30 (?) in s. enayi. the same is valid with regard to s. tosaensis (y abe & toy ama), which, according to the discription, has as much as 50 ramifications in a whorl, though a number of about 30 seems more pro bab le, as indicated by fi g. lc in y abe & toy ama (1949). s. croatica differs from s. istriana (gušić) in much larger ramification diameter, three to four times larger the distance between the whorls, and half the number oframifications per whorl. the differences with regard to s. adriatica( gušić), as revided and emended by de castro & de rosa (1977), are obvious both in much smaller size and the ramification shape, and, therefore, need not be discussed in detail. compared similarities and differences: salpingoporella to s. steinhauseri conrad, praturlon & croatica n.sp. belongs to the group of salpingoporella radoičić, which is characterized by uniformly swelling species in which the ramifications widen more or less ramifications, the difference concerns the following uniformly going to ward their di stal ends, which, then, characteristics: s. croatica has a some what larger th all us results in circular or approximately rounded sections dimensions, perpendicular to sub-perpendicular of the pores. this characteristic distinguishes s. croatica ramifications (in contrast to the inclination of about 45° most clearly from all those species of the genus which in s. steinhausen), and almost twice as much ramifications have distally flattened ramifications, either vertically per whorl (w=7-8 in "s. steinhauseri). s. croatica differs or horizontally, so that the comparison can be restricted from s. cerni radoičić in size; it is much smaller (s. to the members of the first mentioned group. cerni has two to three times larger outer and inner thallus as regards its stratigraphic position, s. croatica comes diameters and larger ramification diameter), regardless most closely to s. pygrnaea(pia), s. enayi bernier, of similar shape, position, and number of ramifications s. eta/lani bernier, ands.johnsoni (dragastan), per whorl. it is worth mentioning that s. cerni, though all of which seem to appear in the late kimmeridgian. originally described from, and hitherto restricted to, in spite of very similar, and in some characters even barremian-aptian deposits, has recently been found also identical dimensions, s. croatica clearly differs from in the kimmeridgian of the biokovo mountain, which s. pygmaea. more precisely, s. croatica shows smaller means that its stratigraphic range should be accordingly ranges of both the outer and inner diameter values, in widened. finally, the differences between s. tur g ida general smaller values of the maximum ramification (radoičić) and s. croatica are visible in that s. turgida diameter, larger distance between the consecutive whorls, has a much more robu st built, a larger thallus, typically and a smaller number of ramifications per whorl, than phloiophorous and longer ramifications, as well as a s. pygrnaea. in addition, s. pygrnaea has more or less larger number of ramifications per whorl. obliquely situated, and often but not always arcuately stratigraphic position: salpingoporella croatica bent ramifications, which widen more or less uniformly n.sp. was found together with the next described species, all along their length. in contrast, in s. croatica the uragiella ragusina n.sp., in a sample with characteristic ramifications.are perpendiculaf,.or,-almest~flictilar;·mierofossil-assemblage; indicating the upper part of the to the axial cavity and have a more pronounced dis tal dogger. a more detailed presentation of the stratigraphic swelling.the dimensional data of s. pygmaea used for position of both species will be given below, after the comparison are from pia (1924), nikler & sokač systematic description of uragiella ragusina n.sp. (1967), bassoulet et al. (1978), sokač & nikler (1973) and bernier (1984). with regard to s.johnsoni, s. croatica has twice as large the outer and inner thallus diameters, considerably larger ramification diameter, and (considerably) larger distances between the consecutive whorls. besides, the number or ramifications perwhorls in s. croatica is about2/3 of that in s.johnsoni. genus uragiella pia, 1924 uragiella ragusina n.sp. pl. ii, figs. 4-22 1966. clypeina (?)sp.radoičić, pl.ciii, fig.l. 1970. unknown dasyclad d-41 -radoičić, p.ioo; pl. il, figs. 1-2. r sokač : two new species ... origin of the name: after the old name of dubrovnik (ragusa), in the en v irons of which the type locality is situated. type locality: the same as for salpingoporella croatica (see above). type stratum: the same as for salpingoporella croatica (see above). holotype: oblique section in thin-section 0-79/92, depicted in pl. ii, fig. 5. the original material is stored at the institute of geology, zagreb. diagnosis: the cylin,drical skeleton is characterized by a narrow central cavity and comparatively thick calcareous walls. the undivided ramifications, widened from their very bases, are arranged into whorls. the most pronounced species-specific characteristic is the variable shape of the ramifications which may be globular, sackor bag-shaped, or similar to the pyriform type, de pending on whether they widen or thin out going tow ard the periphery, and very rarely they look like the uragiella­ type. the variable shape of the ramifications in one specimen results in variously shaped pores in tangential section. thus pores may be circular, four-sided or quadrangular, irregular, or triangular, which influences their arrangement, so that in consecutive whorls the pores may be aligned vertically or, more frequently, they assume a roughly alternating arrangement. description: the new species, uragiella ragusina, was found in a sample of alga! limestone, associated with numerous remains of other dasyclad species, but itself being represented by a comparatively small number of micritized and/or recrystallized sections. this is the reason why some photomicrographs seem to be out of focus, though they are not. the skeleton is cylindrical and comparatively thick-walled, with a narrow axial cavity (or "main stem"). the outer surface appears in thin -sections as a clear and slightly corrugated line, this being probably the result of slight protrusions of individual ramifications on the outer surface (pl.ii, figs. 4,5,8). the narrow main stem is also delineated by clear and not always fully straight line, which suggests shallow depressions at the entrances of ramifications. the "main stem" occupies from 20 to maximally 30% of the total (outer) thallus diameter. the ramifications are undivided and arranged into rather loosely spaced whorls, though the ramifications themselves, being very thick, give the impression of being tightly packed. the ramifications are large and distinctly widened near their base, while more distally they can swell even more, or, on the other hand they can become thinner, so that even in the same specimen they may assume various and irregular shapes (pl. ii, figs. 5, 8). only a few of the ramifications resemble the uragiella-type, more often they are sack-like or pyriform. in some sections, some thin and narrow ramifications seem to occur among the more numerous large and robust ones, which may bring one to the wrong, conclusion about the existence of two types of ramifications. however, this is due to muta! pressure 17 exerted upon the ramifications of the same or of the adjacent whorls, which causes their deformation, resulting in differently shaped pore sections in tangential sections nearer to the surface of the skeleton (pl. il, figs. 8-9, 15). the outer surface is frequently eroded, giving the picture of ramifications open on the outer surface. however, better preserve~ specimens clearly show that the ramifications remain closed within the calcareous envelope. though they come close to the rim, they do not reach the outer surface. the arrangement of ramifications in adjacent whorls seem to be more or less alternating, though this picture is frequently obscured due to irregular shapes of the ramifications. sporadically one can see individual spores within the branches cavities (pl. il, fig.4, 15-19, 21). dimensions in mm: maximum observed length (l) outer thallus diameter (d) inner thallus diameter (d) length of the ramifications (l) number of ramifications in a whorl (w) 2.1 0.48 0.60 0.120.20 0.140.22 89 similarities and differences: the new species has been ascribed to the genus uragiella because of the existence of un divided, simple ramifications, whose shape can vary from sack-like or tubercular to atypically pyriform to sporadically developed uragiella-type. according to the observations of available sections, this species includes also the hitherto uncompletely defined charachter of the genus, i .e. the remifications do not reach the outer surface but, rather, remain closed by their dis tal ends within the calcareous wall. the genus uragiella, according to the present-day knowledge, has a long stratigraphic range from the upper triassic to the senonian and includes only a small number of species. with regard to upper triassic uragiella supratriasica bystricky the new species is clearly distinguished by its variable ramification shape, much smaller overall dimensions, and one half the number of ramifications per whorl than in u. supratriasica. slight similarity exists with liassic u. liasica lebouche & lemo ine, which is only partly evidenced by the existence of sack-like and tubercular ramifications in both species. however, the variability of ramifications, especially in individual specimens, is larger in u. ragusina than in u. liasica. in addition, u. liasica is three to four times larger and has 30% more ramifications per whorl. the differences, between the two, with regard to the type-species, are obvious. u suprajurassica (gumbel, 1881) pia 1925, is much larger and has typical uragiella-type ramifications, and about forty ramification in a whorl.the differences are also very clear when compared to stratigraphically youngest species u. matzi (sokač & velić) since u. mat zi is larger, has almost typical uragiella-iike ramifications, and more ramifications _per wllod._ stratigraphic position: both species described in this paper, salpingoporella croatica n.sp. and uragiella • 18 ragusina n.sp., derive from the same sample of j urassic limestone. the sample was collected during a detailed logging and sampling of the jurassic section extending along the road from osojnik (north of dubrovnik) to the grebci village. the stratigraphic level yielding the sample, as well as the sample itself, which has been determined as the algal-foraminiferal grainstone­ packstone, contains a comparatively rich microfossil assemblage, dominated by numerous remains of calcareous algae. besides new described species in the same sample the most frequent are selliporella donzellii sar10ni & crescentiandneoteutlopjrella gallaeformis (radoićić) bassoulet et al., 1978, which are here conceived in the broadest sence (sensu lato). at this moment i think that it is still uncertain which form exactly, and with what characteristics actualy corresponds to the originally described s. donzellii, and whether n. gallaeformis really represents a younger synonym of s. donzellii, as suggestedbybaratiolo,decastro & radoićić (1988). though taxonomically important, this question has no importance when we discuss the stratigraphic attribution. in the continuous sequence of limestone layers overlying the algal bearing level, foraminifera are becoming more and more abundant, while calcareous algae gradually disappear. thus, about 30-40 meters above the algal-bearing sample, the following foraminiferal species have been identified: paleopfenderinasalemitana (sar toni & crescent!), kilianina blancheti pfender satorina apuliensis fourcade & chorowicz, praekurnubia crusei (remond) and other stratigraphically less important foraminifera. this assemblage is typical of the upper part of the dogger in all the studied jurassic profiles in the costal zone, but cannot be more precisely defined in chronostratigraphic terms. the radoićić's (1970) statement, that u. ragusina occurs in the oldest malm deposits, accompanied by last occurrence of teutloporella and first appearances of cladocoropsis, does not contradict the above attribution, as the microfossil assemblages on both localities are essentially the same. rather, it is only the question of where we should place the dogger/ malm boundary. this, however, does not exclude the possibility of newly described algal species to have a broader stratigraphic range than it has been established in their type locality. references barattolo, f., de castro, p.& radoićić, r. (1988): notes on the genus selliporella s artoni & crescent! 1963 (chlorophyta, đasycla· dales).atti del 74° congresso nazionale, (a), p. 35-38, sorento. bassoullet, j.p., bernier, p., conrad, m.a., deloffre, r. & jaffrezo, m. (1978): les algues dasycladacees du jurassique et du cretace. geobios, mem. spec., 2, p. 1-330, lyon. geologia croatica 45 bernier, p. (1984): les formations carbonates du kimmeridgien et du portlandien dans le jura meridional. stratigraphie, micropaleontologie, sedimentologie.docum. lab. geol., 92/1, p. 1-443, lyon. bystricky, j. (1968): die obertridischen dasycladaceen der westkarpaten.geol. sbomik, 18/2, p. 285309, bratislava. conrad,ma,praturlon,a&radoićić,r.(1973): reinstatement of the genus salpingoporella pia (dasycladaceae) followed by s. steinhauseri n. sp. c. r. soc. 'phys. hist. nat., 7/2-3, p. 103111, geneve. de castro, p. & de rosa, c. (1977): osservazioni su salpingoporella adriatica (gusic, 1966).­ boli. soc. natur., 86, p. 1-39, napoli. dragastan, o. (1971): new algae in the jurassic and lower cretaceous in the bicaz valley (east carpathians) romania.rev. esp. micropal., 3, p. 155-192, madrid. gušić, i. (1966): two new dasyclad species of the subgenus pianella from the lower cretaceous of istria. geol. vjesnik, 19, p. 35-46, zagreb. lebouche, m. c. & lemoine, m. (1963): dasy­ cladacees nouvelles du lias caicaire(lotharingien) du languedoc mediterraneen (st.chinian, boutenac).rev. micropal., 6/2, p. 89-101,paris. nikler, l. & sokać, b. (1967): fossil dasycladaceae from the upper jurassic of the mount velebit and the nw part of the mount velika kapela. -rad jugosl. akad. znan. umjeto., 345, p. 101-132, zagreb. pia, j. (1924): einige neue oder ungentigend bekannte siphoneae verticillatae aus dem mitteleuropaischen malm. ann. naturhist. mus. wien, 38, p. 8288, vv'ien. radoićić, r. (1965): pianella tur g ida n. sp. from the cenomanian of the outer dinari ds. geol. vjesnik, 18, p. 195-199, zagreb. radoićić, r. (1966): microfacies du jurassique des dinarides externes de yugoslavie.geologija, rasprave in poročila, 9, p. 377, ljubljana. radoićić, r. (1968): likanella? danilovae spec. nov. et quelques autres dasycladacees cretacees inferieures des dinarides externes. vesnik za v. geol geof. istr., (a), 26, p. 177-193, beograd. radoićić, r. (1970): algae in the jurassic and the cretaceous of south herzegovina. geol. glasnik, 14, p. 99-107, sarajevo. sokać; b. & velić, i. (1983): uragiella matzi n. sp. (dasycladaceae) from the upper cretaceous of primošten. geol. vjesnik, 36, p. 91-94, zagreb. y abe, h. & toy ama, s. (1949): new dasycladaceae from the jurassic torinosu limestone of the skawabasin sikoku. -proe. jap. acad. tokyo, 25/7, p.40-44, tokyo. sokač : two new species ... 19 dvije nove vrste vapnenačkih alga (dasycladaceae) iz gornjeg dogera južne dalmacije {hrvatska) b. sokač familija dasycladaceae kotzing, 1843 rod salpingoporella pia in trauth, 1918 salpingoporella croatica n.sp. tab. i, tab. il, sl. 1-3. 1970. pianella? sp.radoičić, p. 100, tab. i, sl. 3-4 podrijetlo imena: vezano je na ime moje domovine hrvatske (croatia) kojoj i posvećujem ovu vrstu. tipičan lokalitet: izdanci gomjodogerskih vapnenaca u zasjeku ceste cca 2 km udaljeno od osojnika prema zaseoku grebci (šira okolina dubrovnika, južna dalmacija, hrvatska). koordinate po greenwich za obje nove vrste su: 18.4'40"e, 42.43'29"n. tipični slojevi: svjetlosmeđi dobro uslojeni foraminifersko-algalni grej ns toni do pekstoni iz višeg dijela dogera. istraženo je oko 150 preparata koji su sadržavali brojne primjerke s. croatica i rjeđe u. ragusina. holotip: tangencijalno-uzdužni presjek sadržan u preparatu 0-79/16 prikazan na tab. i, sl. 2. originalni materijal čuva se u institutu za geološka istaživanja, zagreb. dijagnoza: salpingoporella croatica n. sp. cilindričnog skeleta karakterizirana je nepodjeljenim ograncima koji pokazuju tendenciju napuknuća u vanjskom dijelu i generalnim oblikom čine se bliži vesikulifemom nego floifomom tipu, pa se donekle može razlikovati stapka i prošireni distalni kraj. ogranci su u jasno diferenciranim i međusobno dosta razmaknutim pršljenima. bliže matičnoj stanici stoje jedan iznad drugoga dok prema vani nastoje postići alternirajući raspored. opis: cilindričan vapnenački skelet u analiziranim pres jeci m~ redovito je izgrađen od rekristaliziranog kalcita i ponekad je više ili manje povi jen. razarenjem vanjske površine zahvaćene su i pore distalnih krajeva ogranaka, što se u presjecima, kao i kod nekih drugih vrsta ovog roda očituje nazubljenim obrisom vanjskog ruba. centralni kanal ocrtan je jasnom i pravilnom linijom što ukazuje na ravnu unutarnju površinu, koju u nivou pršljena probijaju pore kanalića ogranaka na njihovom proksimalnom kraju. matična stanica zaprima 30-50% ukupnog promjera, ali u pojedinim slučajevima prividno i više, ovisno o intenzitetu razorenosti perifenog dijela skeleta. ogranci su jednostavni, nepodijeljeni i smješteni u jasno diferencirane i međusobno dosta razmaknute pršljenove, što se u ovom slučaju ne čini u potpunosti ovisnim o odebljanju distalnog kraja ogranaka. dio pres jeka s manje erodiranim stijenkama upućuje na oblik ogranaka s nepotpuno diferenciranom drškom i s izrazitijim napuhnućem na distalnom kraju (tab. l, sl. 5, 9-10; tab. ii, sl. 1). generalno, takav oblik ogranaka mogao bi se označiti kao prelazna forma između dobro razvijenog floiofomog i nepotpuno formiranog vesikulifernog tipa. prema dijelu raspoloživih presjeka, izgleda da ogranci dosežu do vanjske površine ali bez značajnih ispupčenja na njoj. takav oblik ogranaka očituje se u tangencijalnim presjecima, neovisno o njihovoj dubini, okruglim porama, kojih je promjerdoprib1ižno polovine ukupne dužine ogranaka u laganom porastu, uz naglije povećanje u vanjskom dijelu. međusobni položaj ogranaka susjednih pršljenova nije uvijek u svim dijelovima jednak. u dubljim tangencijalnim presjecima pore su više ili manje u vertikalnim nizovima (tab. i, sl. 3; tab. ii, sl. 2) , dok se prema distalnom kraju zapaža tendencija ka alternirajućem rasporedu (tab. ii, sl. 1). dimenzije su navedene u engleskom tekstu. sličnosti i razlike: salpingoporella croatica n.sp. pripada skupini salpingoporela kod kojih ogranci više ili manje ravnomjerno odebljavaju prema distalnom kraju, pa se u tangencijalnim presjecima odlikuje okruglim ili približno okruglim parama. ovom značajkom s. croatica jasno se razlikuje od onih vrsta ovog roda, kod kojih su ogranci splošteni bilo u veritkalnom ili horizontalnom smjeru, pa će se njezina usporedba ograničiti na vrste prvospomenute skupine. vrsti s. croatica stratigrafskim položajem najbliže su s. pygmaea (pia), s. enayi bernier, s. etal/oni bernier i s. johnsoni (dragast an) kojih su prve pojave poznate iz gornjeg kimeridža. s. croatica unatoč vrlo sličnih, a u pojedinim elementima i identičnih dimenzija, očito se razlikuje od s. pygmaea. u odnosu na broj analiziranih primjerka, s. croatica pokazuje manji raspon variranja vrijednosti vanjskog i unutarnjeg promjera, općenito manju vrijednost maksimalnog promjera ogranaka, veću udaljenost susjednih pršljenova i manji broj ogranaka u pršljenu, nego što je to u s. pygmaea. razlike među ovim vrstama naznačene su i više ili manje koso položenim, i premda ne uvijek, ali često, lučno povijenim ograncima kao i njihovim približno ravnomjernim odebljanjem prema vanjskom kraju kod s. pygmaea, dok su u s. croatica ogranci okomiti ili subokomiti s izrazitijim odebljanjem u njihovom završnom dijelu, za usporedbu poslužile su dimenzije koje su u svojim radovima za s.pygmaea naveli pia (1924), nikler & sokač (1967), bassoullet et al. (1978), s.okač & nikler (1973) i bernier (1984). s. croailca u odnosu na s.johnsoni dvostruko je većeg vanjskog i unutarnjeg promjera, znatno većeg promjera ogranaka i njihove međusobne udaljenosti sa susjednim pršljenovima, koji osim toga u s. croatica nose za trećinu manji broj ogranaka nego u s.johnsoni. prema vrstama s. et al/oni i s. enayi, uz općenitu sličnost ili, barem, male razlike u pogledu vrijednosti vanjskog i unutarnjeg promjera, s. croatica pokazuje veću 20 variabilnost u ukupnom rasponu iznosa vanjskog i unutarnjeg promjera i zapremini "matične stanice", koja u ove vrste iznosi 30-50%. vidljiva razlika ovdje opisane s dvije prethodno spomenute vrste izražena je brojem ogranaka jednog pršljena, koji za ovu vrstu iznosi 814,apribližno 20 za s. etalloni, odnosno 30? za s. enayi. slično izražena je razlika i prema salpingoporella tossaensis (y abe & toy ama) kod koje vrijednost w prema originalnom opisu iznosi 50, dok poprečni presjek (yabe & tayama, 1949, sl. lc) sugerira približno brojku od 30. s. croatica u odnosu na salpingoporella istriana (gušić) razlikuje se znatno većim promjerom ogranaka, tri do četiri puta većom udaljenošću susjednih pršljenova i do dvostruko manjim brojem ogranaka u pršljenu. od vrste salpingoporella adriatica (gušić), koje su dopunu dali de castro & de rosa (1977), vrsta s. croatica jasno se razlikuje ukupno znatno ma jim dimenzijama i oblikom ogranaka. u odnosu na vrstu salpingoporella steinhauseri (conrad, praturlon & radoičić), koju karakterizira ravnomjerno odebljavanje ogranaka i njihov izrazito kosi položaj prema dužoj osi talusa (kut aproksimativno iznosi 45°) te 7-8 ogrnaka u pršljenu. s. croatica razlikuje se nešto većim dimenzijama talusa, okomitim do subokomii.im položajem ogranaka i njihovim većim brojem u pršljenu. oblikom i položajem ogranaka, te njihovim brojem u pršljenu, s. croatica slična je vrsti salpingoporella cerni (radoičić), koja se međutim razlikuje_dva do tri puta većim promjerom ogranaka. s. cerni, dosada ograničena na barem-apt, prema novim nalazima u kimeridžu biokova }xoširuje svoj ukupni strati grafski raspon. usporedba s. croatica sa salpingoporella tur g ida (radoičić) upućuje na razlike izražene većim talusom, izrazito floiofomim i dužim ograncima te njihovim većim brojem u pršljenu kod s. turgida, koja se uz to odlikuje i općenito grubljom građom. stratigrafski položaj: vrsta s. croatica n.sp. potječe iz uzorka u kojem je sadržana karakteristična fosilna zaje­ dnica iz nivoa označavanog gornjim dogerom. iscrpnija analiza i dokumentacija, potvrde za navedenu stratigrfsku pripadnost biti će dana uz opis slijedeće vrste utvrđene u istom uzorku, a koja je uv~štena u rod uragiella. geologia croatica 45 rod uragiella pia, 1924 uragiella ragusina n.sp. tab. ii, sl. 4-22 1966. clypeina (?) sp. -radoičić, tab. cili, sl. l. 1970. nepoznata dasikladaceja d-41 -radoičić, p. 100; tab. ii, sl. 1-2. podrijetlo imena: ime vrste veže se na stari naziv grada dubrovnika (ragusa) u čijoj je široj okolici smješten tipični lokalitet vrste. · tipičan lokalitet: izdanci u zasjeku ceste cca 2 km udaljeno od osojnika prema naselju grebci (šira okolina dubrovnika, južna dalmacija, hrvatska). tipični slojevi: svjetlosmeđi dobro uslojeni foraminifersko-algalni grejnstone do pekstone iz višeg dijela dogera. holotip: kosi presjek sadržan u preparatu 0-79/92 • prikazan na tab. il, sl. 5. originalni materijal čuva se u institutu za geološka istaživanja, zagreb. dijagnoza: cilindričan skelet karakterizira uska matična stanica i relativno debele vapnenačke stijenke. nepodjeljeni ogranci prošireni već od same baze smješteni su u pršljene. izrazita karakteristika vrste naglašena je variranjem oblika ogranaka koji su okruglasti, vrećasti, nalik piriformnim ovisno da li se sužuju ili proširuju prema vanjskom kraju, vrlo rijetko približavaju se izrazito uragielskom tipu. varijabilni oblik ogranaka na istom primjerku uvjetuje različiti oblik pora u tangencijalnom presjeku. pore su okruglaste, četvrtaste, nepravilne do trokutaste što se odražava i na njihovom međusobnom rasporedu, pa ogranci susjednih pršljena stoje jedan iznad drugog ili su češće približno alternirajućeg rasporeda. opis: vrsta uragiella ragusina n.sp. potječe iz algalnog vapnenca gdje je uz brojne ostatke drugih vapnenačkih alga (dasycladaceae) prisutna relativno malim brojem često mikritiziranih i rekristaliziranih primjeraka, što ima za posljedicu zamućene presjeke, a time i ne uvijek jasne fotografije. odlikuje se cilindričnim skeletom s relativno debelim stijenkama i malom centralnom šupljinom. v an jski rub u presjecima se ocrtava jasnom plitkom nabranomneravnom linijom, što je vjerojatno posljedica slabog ispupčenja pojedinih platetabla i 1-21 salpingoporella croatica n.sp. 1,6-7 longitudinal sections (uzdužni presjeci); figs. 1,6 x 29, fig. 7. x 33 2 tangential oblique section holotype (tangencijalno-kosi presjekholotip); x 29 3,13 tangential sections (tangencijalni presjeci); x 29 4,8,11-12,15-16 oblique sections (kosi presjeci); x 29 5,9-10,14,1-7 oblique-tangential sections (koso-ta-ngencijalni presjeci); figs. 5,9 x 33; figs. 10,14,17 x 29 18-19,21 transversal sections (poprečni presjeci); x 29 20 oblique-transversal section (poprečno-kosi presjek); x 29 sokač : two new species .. . plate -tabla i 21 22 ogranaka na vanjskoj površini (tab. ii, sl. 4-5, 8). vrlo uska matična stanica također je ocrtana jasnom i ne u vi jek ravnom linijom što sugerira plitka ulegnuća na mjestu ulaska ogranaka. matična stanica zaprema od 20 do najviše 30% ukupnog dijametra. nepodjeljeni ogranci smješteni su u relativno dosta razmaknute prši jene, premda odebljali ogranci daju dojam gustog pakovanja. krupni ogranci često naglašeno prošireni već od same baze suzuju se ili proširuju prema distalnom kraju, pa su više manje nepravilnog često varijabilnog oblika i na istom primjerku (tab. ii, sl. 5, 8). samo pojedini ogranci približavaju se uragielskom tipu, ponekad su vrećastog, a u pojedinim slučajevima nalik su i piriformnom obliku. uz generalno krupne ogranke u presjecima pojedinih primjerkaka sporadično se i nepravilno pojavljuju i uski ogranci koji mogu navesti na pomisao o eventualnom postojanju dvije vrste ogranaka. međusobno stiskanje ogranaka istog i susjednih pršljena dovodi do njihovog deformiranja što se odražava različitim oblicima pora u tangencijalnim presjecima blizu površine skeleta (tab. ii, sl. 8-9, 15). unatoč često erodirane vanjske povcline s vidljivo prema vani otvorenim porama ogranaka, bolje očuvani primjerci jasno pokazuju da distalni krajevi ogranaka ostaju unutar vapnenačke stijenke i premda dosežu do blizu ruba skeleta ne izlaze na vanjsku površinu. međusobni raspored ogranaka susjednih pršljena, narušen mogućnošću njihovog različitog oblikovanja, čini se da je ipak više ili manje alternira jući. s obzirom na učestalost kao sporadična odlika može se navesti vidljivost pojedinačnih spora u šupljinama ogranaka (tab. ii, sl. 4, 15-19, 21). dimenzije su navedene u engleskom tekstu. sličnosti i razlike: vrsta uragiella ragusina n.sp. pribrojena je ovom rodu na osnovi nepodjeljenih ogranaka kojih oblik varira od vrećastog ili gomoljičastog preko netipično piriformnog do sporadično razvijenog uragielskog tipa. na osnovi proučavanih pres jeka ova vrsta uključuje i onu nepotpuno definiranu odliku roda, da ogranci ne prelaze vanjsku površinu već distalnim krajem ostaju unutar vapnenačke stijenke. rod uragiella prema sadašnjem saznanju u rasponu od gornjeg trijasa do senona uključuje geologia croatica 45 svega nekoliko poznatih vrsta. u odnosu na gornjotrijasku uragiella supratriasica bystricky 'nova vrsta nedvojbeno se razlikuje prethodno spomenutim varijabilnim oblikom ogranaka, znatno manjim ukupnim dimenzijama i za polovinu manjim brojem ogranaka jednog pršljena nego što je to u tri jaske vrste. u. ragusina pokazuje manje sličnosti s lij askom vrstom uragiella liasica lebo u che & lemoine što je samo donekle izraženo pojavom vrećastih i gomoljičastih ogranaka u obje vrste. međutim, varijabilnost ogranaka, posebice na istom primjerku veća je u vrste u. ragusina. njihova razlika naglašena je tri do četiri puta većim dimenzijama lij aske vrste koja sadrži i za trećinu veći broj ogranaka u jednom pršljenu. prema tipskoj vrsti uragiella suprajurasica (gumbel, 1891) pia 1925, koja je znatno veća i tipičnih m:agielskih ogranaka s oko četrdeset u pršljenu, razlika je očigledna j asna razlika također je vidljiva i prema dosada stratigrafski najmlađoj vrsti uragiella matzi sokač & velić, koja se odlikuje gotovo tipičnim uragielskim ograncima, većim dimenzijama i većim brojem ogranaka u pršljenu. stratigrafski položaj: .obje opisane vrste salpingoporella croatica n.sj\. i uragiella ragusina n.sp. potječu iz istog uzorka prikupljenog prilikom detaljne obrade cjelokupnogjurskog stupa u profiluputaod osojnika (sjeverno od dubrovnika) do naselja grebci. u nešto širem intervalu dijela stupa iz kojega potječe obrađeni uzorak, pa i u samom uzorku koji je determiniran kao algalno-foraminiferski grejnston do pekston, prisutna je relativno bogata fosilna zajednica kojoj osnovno obilježje daju brojni ostaci vapnenačkih algz. učestali su presjeci i fragmenti vrsta selliporella donzellii sartoni & crescent! i neoteutloporellagallaeformis (radoičić)bassoulier et al., 1978. ovom prilikom shvaćenih u širem smislu. u ovom momentu smatram još uvijekneizvjesnimkojaikakva forma i s kojim karakteristikama stvarno odgovara izvorno opisanoj vrsti s. donzellii i da li n. gallaeformis zaista predstavljamlađisinonims.donzellii,štokaosugestijuiznose barattolo, de castro & radoičić (1988). premda ovo pitan je s taksonomskog stajalištazaslužujepunu pažnju, u pogledu determinacije stratigrafskog položaja nije od bitnog značenja. u kontinuiranom slijedu vapnenačkih plate tabla ii 1-3 salpingoporella croatica n.sp. 1-2 tangential sections (tangencijalni presjeci); x 29 3 longitudinal section (uzdužni presjek); x 29 4-22 uragiella ragusina n.sp. 4,7-8,10-11,15,17 oblique to oblique-tangential sections (kosi do koso-tangencijalni presjeci); x 35 5 oblique-longitudinal section holotype (koso-uzdužni presjek holotip); x 35 6 .longitudinal-tangential section (uzdužno~tangencijalni presjek); x 35 9 tangential section (tangencijalni presjek); x 35 12-14,16,19 oblique sections (kosi presjeci); figs. 12-14,16 x 35, figs. 19 x 33 18 transversal section, slightly oblique (poprečni malo kosi presjek); x 33 20-22 transversal sections (poprečni presjeci); figs. 21-22 x 35; fig. 22 x 33. , ' sokač : two new species .. . plate tabla ii 24 naslaga postupno se sve učestalije pojavljuju foraminifere uz istovremeno isčezavanje vapnenačkih alga, pa na 30-40 m iznad uzorka s opisanim vrsiama nalazimo p aleopfenderina salernitana(sartoni&crescenti),kilianinablancheti pfender, satorina apulienensis fourcade & chorowicz, praekurnubiacrusei redmond,te više drugihalimanjestratigrafskiznačaj-nihforaminifera.ovakva zajednica u nekoliko detaljno analiziranih stupova jure duž obalnog pojasa ukazuje da uzorak s opisanim vrsiama s.croatica n.sp. i u.ragusina n.sp. pogeće iz višeg dijela geologia croatica 45 dogera, kojeg nije moguće pouzdanije i detealjnije kronostratigrafski definirati. navod radoičić (1970) da je u.ragusina zapažena u naslagama najstarijeg malma u zajednici s posljednjim nalazima teutloporela i prvim poja­ vama kladokoropsisa nije u koliziji s obzirom na zajednicu jednog i drugog lokaliteta, već je samo u pitanju mjesto gdje će se postaviti granica između dogera i malma. ovime se ne. isključuje veći stratigrafskiraspon opisanih vrsta nego što je on određen na tipskom lokalitetu. manuscript received march, 31. 1992. revised manuscript accepted july, 7. 1992. ab stra ct the b horizons of terra rossa soils developed on three different carbonate lithologies having variable insoluble residue contents were studied in western herzegovina. comparison of their composition and properties illustrates to what extent the mineral, (especially clay mineral assemblage) and particle size distribution of those horizons and the insoluble residue of the underlying carbonate rocks can be used as indicators of the polygenetic nature of terra rossa in this region. terra rossa b horizons have characteristic red colours, neutral to slightly acid ph, high base saturation with calcium as the predominant cation and high cia (chemical index of alteration). the cia values obtained are generally in accordance with mineral composition and particle size distribution of the analysed b horizons. the predominant clay mineral phases in b horizons and related insoluble residues match. kaolinite is the predominant clay mineral phase in the b horizons overlying carbonate rocks containing low amounts of insoluble residue, while smectite predominates in calcarenites areas with a high insoluble residue content. however, the presence of plagioclase, gibbsite, chlorite-vermiculite mixed layer mineral and vermiculite in b horizons overlying carbonate rocks containing low amounts of insoluble residue support a polygenetic origin for the terra rossa. in contrast, terra rossa formed on calcarenites containing high amounts of insoluble residue might have formed almost exclusively from the parent carbonate rock although some infl uence of external materials (e.g. gibbsite) cannot be excluded. this investigation shows that in western herzegovina, an area with no important aeolian input, the content and mineral composition of carbonate rock insoluble residue plays a major role in terra rossa composition. we can tentatively conclude that the lower the insoluble residue content of the parent materials, the greater is the expectation of a more polygenetic origin for the terra rossa. keywords: terra rossa, b horizons, parent materials, (clay) mineralogy, western herzegovina  geologia croatica 67/3 171–183 10 figs. 8 tabs. zagreb 2014 bulk and clay mineral composition indicate origin of terra rossa soils in western herzegovina  1goran durn, 2radica ćorić, 1neven tadej, 1uroš barudžija, 3vedran rubinić and 3stjepan husnjak 1 faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, hr-10000 zagreb, croatia 2 faculty of agriculture and food technology, university of mostar, biskupa čule bb, 88000 mostar, bosnia and herzegovina 3 faculty of agriculture, university of zagreb, svetošimunska 25, hr-10000 zagreb, croatia doi: 10.4154/gc.2014.13 or magnesium. terra rossa is formed as a result of (1) decalcifi cation, (2) rubifi cation and (3) bisiallitisation and/or monosiallitisation (durn et al., 1999). terra rossa is classifi ed as alfi sol (haploxeralf or rhodoxeralf), ultisol, inceptisol (xerochrept) and mollisol (argixeroll or haploxeroll) in soil taxonomy (soil survey staff, 1975). according to the fao system (fao, 1974) terra rossa is recognised as luvisol (chromic luvisol), phaeozem (haplic phaeozem or luvic phaeozem) and cambisol. in other classifi cation systems using the mediterranean climate as the major soil differentiating criterion, the term terra rossa is 1. introduction terra rossa is a reddish clayey to silty/clayey soil developed over limestones and dolomites and is especially widespread in the mediterranean region. a diagnostic feature of terra rossa is a bright red colour originating from rubifi cation, a pedogenic process in which preferential formation of haematite over goethite takes place. due to the underlying highly permeable carbonate rocks, terra rossa is well aggregated and drained, has a slightly alkaline to neutral ph and a base complex almost completely saturated by calcium and/ geologia croaticageologia croatica geologia croatica 67/3geologia croatica 172 used to describe the soil subclass ‘‘modal fersiallitic red soil’’ when situated on limestones (duchaufour,1982). several national soil classifications (e.g. croatia, italy, israel) retain the term ‘‘terra rossa’’ for limestone-derived red soils. the croatian classification puts terra rossa in the class of cambic soils (škorić, 1985). although different authors have considered terra rossa to be a soil, vetusol, relict soil (non-buried-palaeosol), palaeosol or pedosedimentary complex, most scientists consider terra rossa a polygenetic relict soil, formed during the tertiary and/or hot and humid periods of the quaternary (e.g. altay, 1997; bronger & bruhn-lobin, 1997; durn et al., 1999). the nature and relationship of terra rossa to the underlying carbonates is a long-standing problem which has result ed in different opinions with respect to the parent material and origin of terra rossa. the most widely accepted theory is that terra rossa has developed from the insoluble residue of carbonate rocks (tućan, 1912; kišpatić, 1912; kubiëna, 1953; marić, 1964; ćirić & aleksandrović, 1959; plaster & sherwood, 1971; škorić, 1979, 1987; bronger et al., 1983; moresi & mongelli, 1988). other authors have emphasised that the addition of various external materials (e.g. afigeolian dust, volcanic debris, clastic sedimentary particles, bauxite particles) might have masked the influence of limestone and dolomite residues as the primary parent material of terra rossa (balagh & runge, 1970; yaalon & ganor, 1973; šinkovec, 1974; ol son et al., 1980; macleod, 1980; jackson et al., 1982; danin et al., 1983; rapp, 1984; jahn et al., 1991; nihlen & olsson, 1995; altay, 1997; durn et al., 1999, durn, 2003; durn et al., 2007; muhs et. al., 2012). durn et al. (2007) concluded that in some isolated karst terrains, terra rossa may have formed exclusively from the insoluble residue of limestone and dolomite, but it most commonly comprises a variety of external materials that were carried to the carbonate terrain by various transport mechanisms. although it is difficult to estimate accurately the proportions of external materials embedded in the terra rossa soils, durn et al. (2007) estimated that in such a nonisolated karst terrain (such as istria) their contribution might have been up to 50%. muhs et al. (2012) investigated the origin of terra rossa soils overlying very pure carbonate substrates of quaternary age in bermuda. based on the detailed geochemical analyses of trace elements that are immobile in the soil-forming environment, they discovered that terra ros sa soils have been influenced by a combination of lrt dust from africa and local volcanic bedrock. they also concluded that soils on islands in a very broad latitudinal belt of the western atlantic margin have been influenced by african lrt dust inputs over much of the past 500 ka. boero & schwertmann (1989) suggested that terra rossa is formed in a specific pedo-environment which is characterised by an association of mediterranean climate, high internal drainage due to the karstic nature of a hard limestone and neutral ph conditions. they also concluded that it is of little relevance for the process of rubification whether the primary fe sources are autochthonous or allochthonous as long as the general pedoenvironment remains essentially suitable for the formation of terra rossa. based on new field and petrographic evidence, merino & banerjee (2008) proposed a new theory of terra rossa formation, by replacement of limestone by authigenic clay at a narrow reaction front and explained why terra rossa and karst are associated. banerjee & merino (2011) successfully model the new terra rossa–forming process quantitatively and compared mo del-calculated rates of formation of terra rossa to rates obtained palaeomagnetically. the term reddish soils refers to all soils of different shades of red colour developed on carbonate sediments. reddish soils include various types of soils in different phases of soil development: from youngest reddish or brownish calcomelanosols, through terra rossa and calcocambisols to luvisols, which are genetically considered the oldest and most developed soils on carbonate sediments. the basic criterion for distinguishing reddish soils from other soils is the red colour of the diagnostic horizon. chemical and physical properties of soils in western herzegovina, especially reddish soils were subject to investigation by several researchers (bukovac, 1950; resulović et al., 1963; kurtović, 1971; 1979). babić (1989) concluded that the main clay minerals in terra rossa developed on flysch in descending order are smectite, kaolinite and micaceous minerals respectively. tvica (2008) found high base saturation in terra rossa soils from herzegovina with calcium being the predominant cation. terra rossa is the most frequent soil type in western herzegovina (bosnia and herzegovina). among 111.944 ha of reddish soils, terra rossa covers 44.554 ha (39,80%) (fig. 1). according to kurtović (1973; 1979), terra rossa has developed on different types of carbonate rocks (e.g. rudist limestone, brecciated limestone, calcarenite). therefore, terra rossa soils in western herzegovina represent promising material to investigate the influence of the underlying carbonates on the mineral composition and grain-size distribution of terra rossa. the physical, chemical and mineralogical features of the b horizons of terra rossa soils developed on three different carbonate lithologies have been investigated here. the aim of this research was to compare the mineral composition of bulk samples and clay fraction of terra rossa b horizons with the insoluble residues of the underlying carbonate lithologies. this should also show the influence of the insoluble residue content and its grain size on the b horizons of terra rossa for different carbonate lithologies. finally, this work should show to what extent the mineral, (especially clay mineral assemblage) and particle size distribution of the b horizons and insoluble residue of the underlying carbonate rocks can be used as indicators of the polygenetic nature of terra rossa in western herzegovina. 2. materials and methods 2.1. study area the research area is located in the western herzegovina region of bosnia and herzegovina. this region completely lies within the dinarides mountains, which are mostly composed of mesozoic platform carbonates deposited on the adriatic carbonate platform (adcp) (for details see: dragičević durn et al.: bulk and clay mineral composition indicate origin of terra rossa soils in western herzegovina geologia croatica 173 & velić, 2002; tišljar et al., 2002; vlahović et al., 2005). the area between čitluk and široki brijeg is formed from cretaceous carbonate rocks (various types of limestones and dolomites), tertiary carbonates and clastics and quaternary deposits (mojičević & laušević, 1971; raić et al., 1975). according to summarized data from mo jičević & laušević (1973) and raić & papeš (1977), the following lithostratigraphic units can be observed in the field: lower cretaceous (berriasian to aptian) carbonates; albian to cenomanian dolomites and limestones; cenomanian to turonian chondrodont and rudist limestones; turonian to coniacian rudist limestones; palaeocene (liburnian) limestones; palaeocene to lower eocene foraminiferal limestones; middle eocene clastics; neogene (miocene) clastics and carbonates; and quaternary deposits (figure 2). several tectonic phases resulted in folded and overthrust relationships of the cretaceous and tertiary units in the field, together forming the stolac-čitluk tectonic unit (raić & pa peš, 1977). significant amounts of bauxite deposits ac cumulated during the continental phases (at the boundaries between the cretaceous and tertiary and in the middle eocene) in the synforms of the developed palaeorelief. in the neogene, clastic and lacustrine carbonate sedimentation predominated. quaternary deposits accumulated significantly in the lowlands (in karstic dolinas and poljes and in the river valleys) as fluvioglacial, limnoglacial, alluvial, deluvial, proluvial and colluvial material. most of the karstic lowlands in the research area are filled with reddish soils, especially terra rossa, overlying different lithostratigraphical units. 2.2. investigated locations three terra rossa profiles at three different locations (profile 2 at kočerin, profile 5 at čitluk and profile 9 at uzarići) were opened in western herzegovina (figs. 2 and 3). at each location gps coordinates were recorded using mobile mapper 6, magellan professional, as follows: x=6,456,271m, y=4,805,093m (kočerin); x=6,474,991m, y=4,786,373m (čitluk); x=6,469,858m, y=4,801,696m (uzarići). at kočerin medium deep terra rossa is developed on brecciated micritic limestone (fig. 3a). at čitluk luvic terra rossa overlies calcarenite (fig. 3b). shallow terra rossa in uzarići form ed on top of bioclastic floatstone (fig. 3c). at kočerin and uzarići the (b)rz horizon of terra rossa was sampled while at čitluk samples were taken from the bt horizon. (b) rz horizons according to škorić et al. (1985) can be correlated with bw horizons according to fao (2006). in our investigation this horizon is considered to be in direct contact with the carbonate rock. the lowermost bt horizon at čitluk site is also developed on carbonate rock. however, since this profile is that of a luvic terra rossa, (b)rz (ie.: a residual b horizon) horizon was not present and the bt horizon was sampled accordingly. figure 1: a location of bosnia and herzegovina in europe, b – western herzegovina in bosnia and herzegovina, c – distribution of reddish soils in western herzegovina. geologia croatica 67/3geologia croatica 174 2.3. field and laboratory methods soil pits were dug to the contact with carbonate rock, while soil characterization and sampling were done in accordance with škorić (1982; 1986). samples of carbonate rocks were collected immediately from below the soil profiles. disturbed soil samples were collected from all genetic soil horizons and air-dried afterwards. a portion of each disturbed soil sample was gently crushed and sieved through a 2 mm sieve for physical, chemical and mineralogical analyses. soil particle size distribution was determined by the pipette method with sieving and sedimentation after dispersion with sodium pyrophosphate, and interpreted according to fao (2006). the <2 μm fraction of soil samples was separated by sedimentation in a cylinder and quantitatively obtained after the appropriate settling time. soil ph in h2o and in 1 m kcl was measured in 1:2.5 suspension, while the cation exchange capacity (cec) and base saturation (bs) level were determined using barium chloride according to hrn iso 11260 (2004). the chemical composition of soil samples was determined by the commercial acme analytical laboratory, canada. major oxides were determined by x-ray fluorescence (xrf) spectrometer following libo2 fusion. thin sections of carbonate rocks were analysed using a leica dm/lsp petrographic microscope with plane-polarized (ppl) and crossed-polarized light (xpl). samples of carbonate rocks were carefully crushed and sieved to pass through a 2 and 4 mm sieve. fragments in the 2–4 mm range were carefully cleaned in water and only those without impurities were picked. to remove carbonates, the picked fragments of carbonate rocks (2–4 mm) were treated with a 1 m naoac solution buffered at ph 5 with hoac (jackson, 1979; tassier et al., 1979.) the particle size analysis of the insoluble residues was determined after dispersion in water and ultrasonic treatment. fractions >63 μm were obtained by wet sieving. the <2 μm fraction was separated by sedimentation in cylinder and quantitatively obtained after the appropriate settling time. the remaining cylinder content was calculated as representing the 2–63 μm fraction. the mineral composition of <2 mm and <2 μm fractions of soils and the insoluble residue of carbonate rocks (bulk insoluble residue and <2 μm fraction of insoluble residue) was determined by x-ray powder diffraction (xrd) using a philips diffractometer (graphite monochromator, cukμ radiation, proportional counter). xrd patterns of clay fractions figure 2: geological map of the research area with the location of the investigated soil profiles. lithostratigraphic units summarized and partly modified from mojičević & laušević (1971) and raić et al. (1975). durn et al.: bulk and clay mineral composition indicate origin of terra rossa soils in western herzegovina geologia croatica 175 were made after the following treatments: (a) air-drying, (b) glycerol solvation, (c) glycol solvation, (d) heating to 550°c for 2 h and (e) dissolution in hcl (18%) for 24 h. the dmsotreatment was used to differentiate kaolinites which form intercalation compounds with dmso from kaolinites which do not intercalate with dmso (range et al.,1969). by means of semi-quantitative xrd analysis, the amounts of quartz, plagioclase, k-feldspar, haematite, goethite, anatase and gibbsite were determined in the <2 mm and <2 μm fractions of soil samples, bulk insoluble residues and <2 μm fraction of insoluble residues. an external standard was applied, by measuring the relative intensities of characteristic diffraction lines. the identification of clay minerals was generally based on the methods outlined by brown (1961), brindley & brown (1980) and moore & reynolds (1989). the term “illitic material” was used as defined by środoń (1984) and środoń & eberl (1984). the term “mc” was used for mixed-layer clay minerals in which the type of interstratification and constituent clay minerals were not readi ly identifiable. semi-quantitative estimates of clay minerals in the <2 μm fraction were based on the relative intensities of characteristic x-ray peaks following the method of johns et al. (1954). estimated quantities of minerals were presented with xs, but no quantitative value was assigned to each x. figure 3: photos of the investigated soil profiles: a profile 2 (kočerin), b profile 5 (čitluk), c profile 9 (uzarići) figure 4: photomicrograph of bedrock lithology at the kočerin sampling site. diagenetic carbonate crust developed in micritic limestone, showing brecciation and recrystalisation features. (ppl) geologia croatica 67/3geologia croatica 176 3. results 3.1. carbonate rocks results obtained from the micropetrographic analysis of the underlying lithologies at kočerin, čitluk and uzarići showed good correlation with previously determined lithostratigraphy presented on the geological map of the investigated area (fig. 2). the observed profiles with terra rossa were deve­ loped on different lithostratigraphic units as follows: (i) albian to cenomanian dolomites and limestones (kočerin); (ii) middle eocene clastics (čitluk) and (iii) cenomanian to turonian chondrodont and rudist limestones (uzarići). at kočerin, brecciated micritic limestone, showing recrystallisation and development of meteoric diagenetic features figure 5: photomicrograph of bedrock lithology at the čitluk sampling site. calcarenite, predominantly consisting of well-sorted bioclasts and intraclasts, accompanied with minor siliciclastic material (white grains). (ppl) figure 6: photomicrograph of bedrock lithology at the uzarići sampling site. bioclastic floatstone, containing large bioclasts of chondrodonts and rudists and some benthic forams, deposited together with micritic matrix. (ppl) durn et al.: bulk and clay mineral composition indicate origin of terra rossa soils in western herzegovina geologia croatica 177 was recognized. it is interpreted as a diagenetic carbonate crust, developed in the albian to cenomanian dolomite and limestone lithostratigraphic unit (fig. 4). at čitluk, a calcarenite was identified containing predominantly well-sorted, intra-basinal carbonate material (bioclasts and intraclasts), accompanied together with a minor proportion of siliciclastic material (mainly quartz grains), cemented by calcitic cement (fig. 5). according to the observed petrographic characteristics and bioclast assemblage, it belongs to the middle eocene clastics lithostratigraphic unit. rudist and chondrodont limestone, identified as the bioclastic floatstone (dunham, 1962) is observed at uzarići. it contains large (up to several centimetres) bioclasts of chondrodonts and rudists, accompanied by some benthic forams, together embedded in a micritic matrix (fig. 6). this bioclastic limestone belongs to the cenomanian to turonian chondrodont and rudist limestones lithostratigraphic unit. 3.2. soil chemical properties analysed b horizons of terra rossa have neutral to slightly acid ph and high base saturation with calcium as the predominant cation, followed by magnesium (table 1). the highest ph (h2o) was observed in the (b)rz horizon developed on the bioclastic floatstone (uzarići) while the bt horizon in the luvic terra rossa overlying calcarenite has the lowest ph (h2o). as for ph, the bs and humus content were lowest in the bt horizon at čitluk and highest in the (b)rz horizon at uzarići. as expected, the lowest cec value was observed in the bt horizon at čitluk where the lowest ph (h2o) and humus content was detected. namely, the luvic terra rossa at this location is considered the most developed soil among the three analysed locations, and, in addition contains the lowest amount of the clay fraction (table 2). it is also in accordance with wright & foss (1972), who concluded that cec in the lower horizons of soil profiles depended on the clay content and the mineral composition of clay fraction. 3.3. particle size analysis the b horizons of terra rossa profiles at kočerin, čitluk and uzarići have characteristic red colours and are composed of clay, clay loam and clay respectively (table 2). the insoluble residue content of the underlying carbonate rocks is very variable (table 3). it is extremely low in uzarići (0.09 wt.%), low in kočerin (0.61 wt.%) and high in čitluk (18.55 wt.%). all b horizons are enriched in the clay fraction and depleted in the silt fraction compared to the insoluble residue (tables 2 and 3). the content of the sand fraction in the b horizon from kočerin and uzarići is higher compared to the sand content in the insoluble residue of the underlying carbonate rocks (tables 2 and 3). in contrast, the bt horizon developed on calcarenite (čitluk), which has the highest insoluble residue content dominated by the sand fraction is depleted in the sand fraction compared to the insoluble residue. table 1: basic chemical properties of b horizon of the investigated soil profiles. profile depth (cm) horizon ph 1m kcl ph h2o humus (g/kg) ca k mg na cec base saturation (%)cmol kg–1 2 12–28 (b)rz 4.32 5.70 15.85 16.87 0.09 1.07 0.05 18.71 96.63 5 32–84 bt 4.04 5.38 1.90 11.03 0.38 1.73 0.01 15.14 86.85 9 14–38 (b)rz 6.12 7.50 22.10 35.42 0.25 0.76 0.35 36.87 99.76 table 2: mechanical composition of b horizon of the investigated soil profiles. profile depth (cm) soil color dry (munsell soil color chart, 2000) sand 2.0–0.063 mm (%) silt 0.063–0.002 mm (%) clay <0.002 mm (%) texture 2 12–28 2,5yr 4/6 6.50 17.30 76.20 clay 5 32–84 2,5yr 4/6 43.50 24.50 32.00 clay loam 9 14–38 10r 4/4 7.50 25.10 67.40 clay table 3: particle size analysis of the insoluble residues of limestone (wt.%). profile i.r. content (%) sand 2.0–0.063 mm (%) silt 0.063–0.002 mm (%) clay <0.002 mm (%) texture 2 0.61 4.14 44.33 51.53 silty clay 5 18.55 50.87 26.28 22.85 sandy loam 9 0.09 2.14 33.62 64.24 clay ir = content of the insoluble residue (wt.%). geologia croatica 67/3geologia croatica 178 3.4. geochemical indicators of weathering in order to characterize the investigated b horizons geochemically, we used the chemical index of alteration (cia) proposed by nesbitt & young (1982) and considered the measure of feldspar minerals weathering and their hydration to form clay minerals (sheldon & tabor, 2009) and ti/al molecular ratio, which can also be used as provenance indicator (e.g. sheldon, 2006; stiles & stensvold, 2008). cia values range from 84.73 in čitluk to 93.32 in kočerin and can be considered as very high (table 4). the ti/al ratios in bulk samples range from 0.040 in kočerin to 0.060 in čitluk (table 4). 3.5. bulk and clay mineralogy mineralogical analyses were performed on the <2 mm and <2 μm fractions of the b horizons (tables 5 and 6; figs. 7 and 9) and the insoluble residue of carbonate rocks (bulk insoluble residue and <2 μm fraction of insoluble residue) (tables 7 and 8: figs. 8 and 10). though the mineralogical composition of non-clay minerals in all three b horizons was relatively uniform (table 5), significant differences in clay mineral composition among the investigated b horizons were observed (table 6). each b horizon contained quartz, k-feldspar, haematite, goethite, gibbsite, kaolinite, mc and xrd-amorphous inorganic compounds. both kaolinite which does not form intercalation compounds with dmso and kaolinite which intercalates with dmso were detected. the presence and distribution of plagioclase, anatase, smectite, vermiculite, micaceous clay minerals (illitic material and mica) and chlorite–vermiculite mixed layer mineral (c/v) varied among the different b horizons. the bt horizon from čitluk contains the highest amount of quartz (in both table 4: selected geochemical properties of b horizon of the investigated soil profiles. profile depth (cm) cia al*100/(al+ca+k+na) ti/al 2 12–28 93.32 0.040 5 32–84 84.73 0.060 9 14–38 86.81 0.051 cia=chemical index of alteration calculated as al * 100 / (al+ca+k+ na). table 5: semi-quantitative mineral composition of the <2 mm fraction of b horizons of the investigated soil profiles. phyllos.+am.= phyllosilicates + amorphous inorganic compound, + = mineral is present in the sample. ? = mineral is probably present in the sample but due to the low content and/or overlapping of diffraction peaks cannot be confirmed with certainty. profile depth (cm) quartz (%) plagioclase (%) k-feldspar (%) hem.+goeth. (%) anatase gibbsite (%) phyllos.+am. (%) 2 12–28 18 ? <1 7 + 10 60 5 32–84 60 <1 <1 4 ? + 30 9 14–38 23 ? <1 7 ? + 65 table 6: semi-quantitative mineral composition of the <2 μm fraction of b horizons of the investigated soil profiles. + = mineral is present in the sample. ? = mineral is probably present in the sample but due to the low content and/or overlapping of diffraction peaks cannot be confirmed with certainty. c/v=mixed-layer chlorite-vermiculite. pr ofi le d ep th (c m ) q ua rt z (% ) pl ag io cl as e (% ) kfe ld sp ar (% ) h em .-g oe th . (% ) g ib bs ite (% ) an at as e ka ol in ite sm ec tit e ve rm ic ul ite ill iti c m at er ia l m ix ed -la ye r cl ay m in er al am . m at te r 2 12–28 ? ? – 9 14 + xxx – xx ? xx (c/v) x 5 32–84 9 ? – 8 – ? x xxx – ? x x 9 14–38 3 – – 8 – ? xxx ? – x xx (c/v) x x relative abundance of clay minerals within horizons based on x-ray diffraction (no quantitative value is assigned to x) figure 7: x-ray diffractograms of bulk sample (a) and clay fractions (b to f) of the analyzed (b)rz horizon from kočerin, a-untreated, b-untreated, cglycerol solvated, d-ethylene glycol solvated, e-heated for 2 hours at 550°c. f-treated 24 hours with hcl (18%). qtz: quartz. pl: plagioclase. kfs: potassium feldspar. gbs: gibbsite. gt: goethite. m: micaceous mineral. kln: kaolinite. vrm: vermiculite. s: smectite. ill: illitic material. mc: mixed-layer clay mineral. chl/vrm: mixed-layer chlorite/vermiculite. durn et al.: bulk and clay mineral composition indicate origin of terra rossa soils in western herzegovina geologia croatica 179 fractions) and only in this sample was the presence of plagioclase confirmed with certainty. although gibbsite was recognized in all b horizons, its content is highest in the (b) rz horizon from kočerin (in both fractions). kaolinite is the predominant clay mineral phase in the clay fraction of the (b)rz horizons from kočerin and uzarići while smectite is the predominant clay mineral phase in the clay fraction of the bt horizon from čitluk (table 6; figs. 7 and 9). kaolinite is followed by vermiculite and c/v as the main mineral phases in kočerin and by c/v and illitic material in uzarići. it is important to emphasize that illitic material was confirmed with certainty only in the (b)rz horizon from uzarići. kaolinite and mc follow smectite in čitluk in terms of quantity. significant differences in both the non-clay and clay mineral composition of the analysed insoluble residues (ir) were observed (tables 7 and 8). each ir contained quartz, goethite, kaolinite and an xrd-amorphous inorganic compound. both kaolinite which does not form intercalation compounds with dmso and kaolinite which intercalates with dmso were detected. the presence and distribution of plagioclase, k-feldspar, haematite, anatase, gibbsite, smectite, micaceous clay minerals (illitic material and mica), mc, c/v and illite/smectite mixed-layer mineral (i/s) varied among the different ir. ir from čitluk contains the highest amount of quartz (in both fractions), and plagioclase and kfeldspar were detected in this sample alone. ir from kočerin contains the highest amount of goethite and is the only sample with gibbsite (in both fractions). kaolinite is the predominant clay mineral phase in the clay fraction of ir from kočerin and uzarići while smectite is the predominant clay mineral phase in the clay fraction of ir from čitluk (table 8; figs. 8 and 10). kaolinite is followed by smectite, illitic material and i/s in kočerin and is the only clay mineral phase in uzarići. smectite is followed by illitic material, kaolinite and i/s in čitluk. 4. discussion and conclusion the terra rossa soils analysed from western herzegovina occur over carbonate rocks of different ages and lithologies (figs. 2, 4, 5 and 6) having very variable ir contents (table 3) ranging from extremely low (0.09 wt.% in uzarići) to table 7: semi-quantitative mineral composition of the insoluble residues of limestone. phyllos.+am.= phyllosilicates + amorphous inorganic compound, + = mineral is present in the sample. ? = mineral is probably present in the sample but due to the low content and/or overlapping of diffraction peaks cannot be confirmed with certainty. profile depth (cm) quartz plagioclase k-feldspar goethite hematite anatase gibbsite phyllos.+am. 2 30–50 32 – – 10 ? ? 5 50 5 90–110 48 12 8 + – – – 30 9 40–60 20 – – + – – – 75 table 8: semi-quantitative mineral composition of the <2 μm fraction of the insoluble residues of limestone. + = mineral is present in the sample. ? = mineral is probably present in the sample but due to the low content and/or overlapping of diffraction peaks cannot be confirmed with certainty. * = the amount of insoluble residue was very low (see table 3) and clay fraction was not separately analysed. ** = insoluble residue contains only kaolinite as a clay mineral phase. c/v = mixed-layer chlorite-vermiculite. i/s = mixed-layer illite/smectite. pr ofi le d ep th (c m ) q ua rt z (% ) g oe th ite (% ) g ib bs ite (% ) an at as e ka ol in ite sm ec tit e ve rm ic ul ite ill iti c m at er ia l m ix ed -la ye r cl ay m in er al am . m at te r 2 30–50 ? 12 + ? xxx xx – x x (i/s) xx 5 90–110 7 + – – x xxx – xx x (i/s) xx 9* 40–60 xxx** x relative abundance of clay minerals within horizons based on x-ray diffraction (no quantitative value is assigned to x) figure 8: x-ray diffractograms of bulk sample (a) and clay fraction (b to e) of insoluble residue of limestone from kočerin, a-untreated, b-untreated, c-ethylene glycol solvated, d-glycerol solvated, e-heated for 2 hours at 550°c. for abbreviations see fig. 7. geologia croatica 67/3geologia croatica 180 high (18.55 wt.% in čitluk) values. terra rossa b horizons have characteristic red colours (table 1), neutral to slightly acid ph and high base saturation, with calcium as the predominant cation, followed by magnesium (table 1). it is in accordance with tvica (2008) who observed high base saturation in terra rossa soils from herzegovina with calcium as the predominant cation. very high cia values in the b horizons of the analysed soils clearly indicate intensive weathering (table 4). according to sheldon & tabor (2009), parent materials that have already been cycled as sediments or which are clayrich, may start out with cia values of 60 to 70%. they state that as weathering progresses from, for example, microcline to illite and kaolinite, cia values would increase from 50 to 75 (pure illite) and 100 (pure kaolinite), respectively. the cia values obtained in this study are generally in accordance with the mineral composition and particle size distribution of the analysed b horizons. traces of k-feldspar and plagioclase, the predominance of kaolinite as well as the clay fraction content are in favour of high cia in the (b)rz horizons from kočerin and uzarići (tables 2, 4, 5 and 6). the slightly lower cia value observed in the bt horizon from čitluk is due to the significantly lower clay fraction (higher amount of silt and especially sand fraction) and to smectite as the predominant clay mineral phase. however, it has to be stressed that cia values are partly masked by the presence of gibbsite (i.e. aluminium hydroxide) that was detected in all the analysed b horizons. the effect of particle size distribution is also evident in the ti/al ratios because the highest ratio was observed in the bt horizon from čitluk with the highest amount of sand fraction and, likewise, the highest ti content, while the lowest ratio was found in the (b)rz horizon from kočerin with the highest clay content. unfortunately, due to this effect of particle size, the ti/al ratio could not be used as a provenance indicator. the content of the insoluble residue may indicate that in the case of kočerin and uzarići locations, an excessive thickness of carbonate rocks must have been dissolved to form the (b)rz horizons of terra rossa, and that also the extent of the preservation of that residue must have been very high. in contrast, it is quite plausible that the bt horizon at čitluk might have formed from the insoluble residue of the calcarenite. although the insoluble residue of carbonate content of carbonate rocks below the (b)rz horizons in kočerin and uzarići is not compatible with the development of terra rossa entirely by the dissolution of carbonate rocks, its grain size distribution provides a different picture. namely, if terra rossa has developed only from the insoluble residue of limestone or dolomite, its clay content, due to weathering should be higher than that observed (tables 2 and 3). in order to resolve such questions, the clay fraction may be of great importance because its composition could be a result of different processes which may have taken place during soil formation. namely, soils may contain “detrital”clays inherited from the parent material (in this case soil clays represent the ir of carbonate rock) and they may contain clays formed by sequential weathering of unstable parent minerals of the ir (including clay mineral phases). there are also neoformed (pedogenic) clay minerals and clays added to the soil due to allochthonous inputs (e.g. aeolian dust, volcanic debris and clastic sedimentary particles; durn et al., 2007). this is even more complex when soils are formed on carbonate rocks that are extremely low in non-carbonate mineral phases. figure 9: x-ray diffractograms of bulk sample (a) and clay fraction (b to f) of analyzed btg horizon from profile čitluk, a-untreated, b-untreated, c-glycerol solvated, d-ethylene glycol solvated, e-heated for 2 hours at 550°c. f-treated 24 hours with hcl (18%). for abbreviations see fig. 7. figure 10: x-ray diffractograms of bulk sample (a) and clay fraction (b to e) of insoluble residue of limestone from čitluk, a-untreated, b-untreated, c-ethylene glycol solvated, d-glycerol solvated, e-heated for 2 hours at 550°c. for abbreviations see fig. 7. durn et al.: bulk and clay mineral composition indicate origin of terra rossa soils in western herzegovina geologia croatica 181 with regard to the previous statement, the situation is clearest at čitluk because there the calcarenite contains a high amount of ir, 18.55 wt.% respectively (table 3). luvic terra rossa at this location is thickest (table 1) and is considered to be the most developed soil of the three analysed locations. the clay mineral composition in the bt horizon and ir match quite well (tables 6 and 8). the presence of smectite as the predominant clay mineral phase in both the ir and bt horizons clearly indicates that this mineral phase was inherited from the parent material. kaolinite is present in both the ir and bt horizons and can also be, at least partly, considered as inherited. namely, the bt horizon contain both types of kaolinite while kaolinite which forms intercalation compounds with dmso is the predominant type of this mineral phase in the ir. this may indicate that the kaolinite which does not intercalate with dmso is predominantly pedogenic kaolinite, i.e., an authigenic mineral in terra rossa, while kaolinite which intercalates with dmso is inherited from the kaolinite containing parent material which means it is of a lithogenic origin (durn et al., 1999). illitic material and i/s detected in ir were not found with certainity in the bt horizon probably due to their very low content. however, the presence of mc in the bt horizon may indicate these phases were the source material for more weathered clay minerals. a much higher content of kaolinite would be expected in the luvic terra rossa but smectite seems to be the (meta)stable mineral phase in this pedoenvironment because the ph was not low enough to inhibit smectite stability, (e.g. douglas, 1982; karathanasis & hajek, 1984 ) and ca and mg are the predominant cations in the soil solution (table 1). due to their chemical composition, the dissolution of smectite minerals is driven by different mechanisms. in particular, hydrolysis of octahedral mg is interpreted as the primary driving force behind the dissolution of saponite in dilute acid, while reduction should play a major role in the decomposition of nontronite (ryan et al., 2008). a higher content of quartz and much lower contents of unstable mineral phases including plagioclase and k-feldspar in the bt horizon compared to ir (tables 5 and 7) also favour calcarenite as the parent material for the luvic terra rossa at čitluk. therefore we can conclude that both the mineral composition and the particle size distribution of the bt horizon and ir suggest calcarenite as terra rossa parent material. minor external material contributions by various transport mechanisms cannot be excluded as documented by gibbsite which we consider to be the only external material in terra rossa at this location. as previously stated, in the case of kočerin and uzarići, the ir content of carbonate rocks below terra rossa may indicate that an excessive thickness of carbonate rocks was dissolved to form the (b)rz horizons, and that the degree of the preservation of that residue must have been very high. kaolinite is the predominant clay mineral phase in both the ir and the (b)rz horizon at those locations. we tentatively propose the same origin of kaolinite as in the case of čitluk. however, two clay mineral phases (c/v and vermiculite) were detected in the (b)rz horizons from these locations that were not found in the ir of brecciated micritic limestone (kočerin) and bioclastic floatstone (uzarići) (tables 6 and 8). we tentatively propose three possible explanations for the c/v and vermiculite origin in the analysed (b)rz horizons with the first or/and third one being the most probable. firstly, c/v and vermiculite are considered as soil clay minerals because those mineral phases were not detected in the ir of the corresponding carbonate rocks. the presence of c/v may indicate that both mineral phases formed as a result of chlorite destabilization, with c/v as an intermediate step during the vermiculitization process of chlorite sensu wilson (2004). this explanation is valid only when chlorite was present as an allochthonous mineral phase because this mineral was not detected in the ir of corresponding carbonate rocks. the presence of vermiculite in (b)rz horizon from kočerin and lack of this clay mineral in (b)rz horizon from uzarići can probably be attributed to the lower ph of kočerin (table 1). secondly, it is possible that vermiculite formed by weathering of the illite, mineral phase detected in the ir of carbonate rocks from kočerin and čitluk. for example, ottner et al. (2013) state that illite can be the source material for more weathered clay minerals in the oberlab loess-palaeosol sequence in upper austria. however, the lack of illite in the ir from uzarići, as well as the lack of vermiculite in the bt horizon from čitluk do not support this explanation. this second explanation also does not provide an answer for the origin of c/v. thirdly, it is possible that both mineral phases were not formed in soil from allochthonous chlorite but are derived as mineral phases already present in “external” material. the presence of plagioclase as a trace mineral phase in kočerin (plagioclase was not detected in ir of brecciated micritic limestone) and the presence of gibbsite in both (b)rz horizons locations support both the first and/or the third explanation. we can conclude that both the mineral composition of the (b)rz horizon and ir as well as the very low ir content of carbonate rocks below terra rossa strongly suggest a substantial contribution of external material during the genesis of terra rossa in kočerin and uzarići compared to čitluk. the positions of the three investigated locations on the geological map (fig. 2) clearly indicate that the sampling sites in kočerin and uzarići are situated in the vicinity of quaternary deposits which could have been the possible source of external materials while čitluk is situated in a more isolated position where the influence of external materials is less important. although the ir of brecciated micritic limestone from kočerin contains gibbsite, (probably from cracks in limestones and, therefore, of secondary origin), we relate the presence of this mineral phase in all b horizons to reworked particles of palaeogene bauxites which are sporadically present in the area of investigation (raić & papeš, 1977). based on their studies of terra rossa soils in istria durn et al. (2007) concluded that in some isolated karst terrains, terra rossa may have formed exclusively from the ir of limestone and dolomite, but it is most commonly composed of a geologia croatica 67/3geologia croatica 182 variety of external materials, including aeolian dust, volcanic debris and clastic sedimentary particles that were carried to the carbonate terrain by various transport mechanisms. they found that the most likely additional flux influencing terra rossa formation in istria is aeolian dust, followed by flysch sediments and their contribution might have been up to 50%. based on investigation of the b horizons of terra rossa on three locations in western herzegovina we can conclude the following: (1) terra rossa situated on isolated carbonate rocks containing high amount of ir may have formed almost exclusively from the parent carbonate rock (čitluk) although some influence of external materials cannot be excluded (e.g. gibbsite). (2) terra rossa formed on non-isolated carbonate rocks containing low amounts of ir (kočerin and uzarići) clearly shows the influence of external materials on its genesis (e.g. chlorite, plagioclase, gibbsite) and can be regarded as polygenetic soil (durn et al., 1999; 2007). it is important to stress that compared to istria where loess deposition has been a recurrent process since the early middle pleistocene and influenced terra rossa formation (durn et al., 1999; 2007) no data on loess deposition in western herzegovina is reported in the literature. acknowledgment this research was supported by croatian science fondation (project 2504). references altay, i. (1997): red mediterranean soils in some karstic regions of taurus mountains, turkey.– catena, 28, 247–260. babić, s. (1989): physical, chemical and mineralogical characteristics of terra rossa and eutric red-brown (eutric cambisol) of herzegovina.– zemljište i biljka, 38, 7–17, beograd. balagh, t.m. & runge, e.c.a. (1970): clay-rich horizons over li me stone, illuvial or residual.– soil sci. soc. am. proc., 34, 534–536. banerjee, a. & merino, e. (2011): terra rossa genesis by replacement of limestone by kaolinite. iii. dynamic quantitative model.– the journal of geology, 119, 259–274. boero, v. & schwertmann, u. (1989): iron oxide mineralogy of terra rossa and its genetic implications.– geoderma, 44, 319–327. brindley, g.w. & brown, g. (1980): crystal structures of clay minerals and their x-ray identification. miner. soc., london, 495 p. bronger, a. & bruhn-lobin, n. (1997): paleopedology of terrae rossae – rhodoxeralfs from quaternary calcarenites in nw morocco.– catena, 28, 279–295. bronger, a., ensling, j., gütlich, p. & spiering, h. (1983): rubification of terrae rossae in slovakia: a mösbauer effect study.– clays clay miner., 31, 269–276. brown, g. (1961): the x-ray identification and crystal structures of clay minerals.– miner. soc., london, 544 p. bukovac, p. (1950): prilog poznavanju tla zapadne hercegovine.– poljo privredna znanstvena smotra, sv. 12, zagreb. ćirić, m. & aleksandrović, d. (1959): a view on the genesis of terra rossa.– zbornik radova poljoprivrednog fakulteta, 7, 1–12, beograd. danin, a., gerson, r. & carty, j. (1983): weathering patterns on hard limestone and dolomite by endolithic lichens and cyanobacteria: supporting evidence for eolian contribution to terra rossa soil.– soil science, 136, 213–217. douglas, l.a. (1982): smectites in acidic soils.– in: van olphen, h. & veniale, f. (eds.): proc. int. clay conf. in bologna, pavia. elsevier, amsterdam, 635–640. dragičević, i. & velić, i. (2002): the northeastern margin of the adriatic carbonate platform.– geol. croat, 55/2, 185–232, zagreb. duchaufour, p. (1982): pedology: pedogenesis and classification.– allen and unwin, london, 448 p. dunham, j.b. (1962): classification of carbonate rocks according to depositional texture.− in: ham, w.e. (ed.): classification of carbonate rocks.– amer. assoc. petrol. geol. mem., 1, 108−121. durn, g. (2003): terra rossa in the mediterranean region: parent materials, composition and origin.– geol. croat, 56/1, 83–100, zagreb. durn, g., ottner, f. & slovenec, d. (1999): mineralogical and geochemical indicators of the polygenetic nature of terra rossa in istria, croatia.– geoderma, 91, 125–150. durn, g., aljinović, d., crnjaković, m. & lugović, b. (2007): heavy and light mineral fractions indicate polygenesis of extensive terra rossa soils in istria croatia.− in: mange, m.a & wright, d.t. (eds.): heavy minerals in use 701−737, developments in sedimentology, 58, elsevier. fao (1974): soil map of the world, 1:5 mill., volume 1. legend.– unesco, paris. fao (2006): guidelines for soil description, 4th edition. fao, rome. hrn iso 11260 (2004): soil quality − determination of effective cation exchange capacity and base saturation level using barium chloride solution (iso 11260:1994+cor 1:1996). jackson, m.l. (1979): soil chemical analysis − advanced course.– soil science dept., university of wisconsin, madison, 250 p. jackson, m.l., clayton, r.n., violante, a. & violante, p. (1982): eolian influence on terra rossa soils of italy traced by oxygen isotopic ratio.– in: van olphen, h. & veniale, f. (eds.): 7th int. clay conf. pavia, italy, 293–301. jahn, r., zarei, m. & stahr, k. (1991): genetic implications of quartz in “terra rossa” soils in portugal.– proceedings of 7th euroclay conference, dresden, 541−546. johns, w.d., grim, r.e. & bradley, w.f. (1954): quantitative estimations of clay minerals by diffraction methods.− jour. sed. petr., 24, 242–251. karathanasis, a.d. & hajek, b.f. (1984): evaluation of alluminum-smectite stability equilibria in naturally acidic soils.− soil sci. soc. am. j., 48, 413–417. kišpatić, m. (1912): bauxites des kroatischen karstes und ihre einstehung.– n. jb. min. geol. pal., 34, 513–552. kubiëna, w.l. (1953): the soils of europe.– thomas murby and co., london, 317 p. kurtović, j. (1973): prilog poznavanju faktora koji čine crvenice najboljim duhanskim tlima u hercegovini, simpozij o inrodukciji i proizvodnji krupnolisnih i visokoprinosnih sorata duhana u sfrj, 173–191, duhanski institut, mostar. kurtović, j. (1979): agropedološka studija reona proizvodnje duhana u čitluku sa pedološkom kartom i kartom plodnosti tla.– zbornik radova, duvanski institut, mostar, 182 p. macleod, d.a. (1980): the origin of the red mediterranean soils in epirus, greece.– j. soil sci., 31, 125–136. marić, l. (1964): terra rossa u karstu jugoslavije.– acta geologica, 4, 19–72, zagreb. merino, e. & banerjee, a. (2008): terra rossa genesis, implications for karst, and eolian dust: a geodynamic thread.− the journal of geology, 116, 62−75. durn et al.: bulk and clay mineral composition indicate origin of terra rossa soils in western herzegovina geologia croatica 183 mojičević, m. & laušević, m. (1971): osnovna geološka karta sfrj 1:100000. list mostar k33–24 [basic geological map of sfry 1:100000. the mostar sheet].– geološki zavod sarajevo (1958–1969), savezni geološki zavod, beograd. mojičević, m. & laušević, m. (1973): osnovna geološka karta sfrj 1:100000. tumač za list mostar k33–24 basic geological map of sfry 1:100000. geology of the mostar sheet.– geološki zavod sarajevo, savezni geološki zavod beograd, 48 p. moore, d.m. & reynolds, r.c. (1989): x-ray diffraction and the identification and analysis of clay minerals.– oxford university press, oxford, 326 p. moresi, m. & mongelli, g. (1988): the relation between the terra rossa and the carbonate-free residue of the underlying limestones and dolostones in apulia, italy.– clay minerals, 23, 439–446. muhs, d.r., budhan, j.r., prospero, j.m., skipp, g. & herwitz, s.r. (2012): soil genesis on the island of bermuda in the quaternary: the importance of african dust transport and deposition.– j. geophys. res., 117, f03 025, doi.: 10.1029/2012 jf 002366. munsell soil color charts (1994): macbeth division of kollmorgen instruments.– new windsor, new york, usa. nesbitt, h.w. & young, g.m. (1982): early proterozoic climates and plate motions inferred from major element chemistry of lutites.– nature, 299, 715–717. nihlen, t & olsson, s. (1995): influence of eolian dust on soil formation in the aegean area.– zeitschrift für geomorphologie, 39/3, 341–361. olson, c.g., ruhe, r.v. & mausbach, m.j. (1980): the terra rossa limestone contact phenomena in karst.– southern indiana soil sci. soc. am. j., 44, 1075–1079. ottner, f., sedov, s., odbatar, u. & wriessnig, k. (2013): grain size and mineralogical indicators of weathering in the oberlaab loess-paleosol sequence, upper austria.− quaternary science journal, 62, no 1, 34–43. plaster, r.w. & sherwood, w.c. (1971): bedrock weathering and residual soil formation in central virginia.– geol. soc. am. bull., 82, 2813–2826. raić, v., papeš, j., behilović, s., crnolatac, i., mojićević, m., ranković, m. slišković, t. đorđević, b., golo, b., ahac, a., luburić, p. & marić, lj. (1975): osnovna geološka karta sfrj 1:100000. list metković k33-36 [basic geological map of sfry 1:100000. the metković sheet].– geološki zavod sarajevo (1958–1971), savezni geološki zavod, beograd. raić, v. & papeš, j. (1977): osnovna geološka karta sfrj 1:100000. tumač za list metković k33-36 [basic geological map of sfry 1:100000. geology of the metković sheet].geološki zavod sarajevo, savezni geološki zavod beograd, 39p. range, k.j., range, a. & weiss, a. (1969): fire-clay type kaolinite or fire-clay mineral? experimental classification of kaolinite– halloysite minerals.– proc. 3rd int. clay conf., tokyo 1, 3–13. rapp, a. (1984): are terra rossa soils in europe eolian deposits from africa?– geologiska foreninges et stockholm forhandlingar, 105, 161–168. ryan, p.c., hillier, s. & wall, a.j. (2008): stepwise effects of the bcr sequential chemical extraction procedure on dissolution and metal release from common ferromagnesian clay minerals: a combined solution chemistry and x-ray powder diffraction study.– sci. total environ, 407, 603–614. resulović, h., živanov, n. & jovandić, p. (1963): karakteristike sastava adsorptivnog kompleksa na jednoj razvojnoj seriji tla na trijadičnom krečnjaku.– zemljište i biljka, vol. xii, no. 1–3, beograd. sheldon, n.d. (2006): abrupt chemical weathering increase across the permian–triassic boundary.– palaeogeogr. palaeoclimatol. palaeoecol, 231, 315–321. sheldon, n.d. & tabor, n.j. (2009): quantitative paleoenvironmental and paleoclimatic reconstruction using paleosols.– earthsci. rev., 95/1–2, 1–52. soil survey staff (1975): soil taxonomy: a basic system of soil classification for making and interpreting soil surveys.– usda handbook no. 436, u.s. government printing office, washington, d.c. środon, j. (1984): x-ray powder diffraction identification of illitic materials.– clays clay miner., 32, 337–349. środon, j. & eberll, d.d. (1984): illite.– in: bailey, s.w. ed., micas. rev. miner. 13, miner. soc. america, 495–544. stiles, c.a. & stensvold, k.a. (2008): loess contribution to soils forming on dolostone in the driftless area of wisconsin.– soil sci. soc. am. j, 72, 650–659. šinkovec, b. (1974): porijeklo terra rosse istre.– geološki vjesnik, 27, 227–237. škorić, a. filipovski, g. & ćirić, m. (1985): klasifikacija tala jugoslavije.– posebna izdanja, 13, akademija nauka i umjetnosti bih, odj. prirodnih i matematičkih nauka, sarajevo. škorić, a. (1979): dvoslojni profili tla na području terra rosse u istri.– zemljište i biljka, 28, 111–131, beograd. škorić, a. (1987): pedosfera istre.– project council of pedological map of croatia, special ed., 2, zagreb, 192 p. tassier, a., campbell, p.c.g. & bisson, m. (1979): sequential extraction procedure for the speciation of particulate trace metals.– analytical chemistry, 5, 844–851. tišljar, j., vlahović, i., velić, i. & sokač, b. (2002): carbonate platform megafacies of the jurassic and cretaceous deposits of the karst dinarides.– geol. croat., 55/2, 139–170, zagreb. tućan, f. (1912): terra rossa, deren natur and entstehung.– jahrbuch min. geol. pal., xxxiv beilage, 401–430. tvica, m. (2008): stanje organskog karbona u važnijim tipovima zemljišta zavisno od načina korištenja.– magistarski rad, univerzitet u sarajevu, 89 p. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeogr. palaeoclimatol., palaeoecol, 220, 3–4; 333–360. yaalon, d.h. & ganor, e. (1973): the influence of dust soils during the quaternary.– soil science, 116, 233–251. wilson, m.j. (2004): weathering of the primary rock-forming minerals: processes, products and rates.– clay miner. 39/3, 233–266. wright, w.r. & foss, j.e. (1972): contributions of clay and organic matter to the cation exchange capacity of maryland soils.– soil sci. soc. am. j., 36/1, 115–118. manuscript received june 20, 2014 revised manuscript accepted september 16, 2014 available online october 31, 2014 2021 | 74/1 | 57–72 | 11 figs. | 7 tabs. | 2 pls. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction remote sensing is an emerging technology discipline that began with the successful launch of the multispectral scanner (mss) on the united states’ landsat (landsat) in 1972 (wang et al., 2011; alijagić & šajn, 2020). since then, coupled with the continuous development of space remote sensing and satellite sensor technology in recent years, a variety of high-resolution and improved remote sensing data has emerged both locally as well as globally. for instance, worldview–2 (shang, 2009) and quickbird have both reached metre-level resolution, while worldview–3, launched in 2014, has achieved 0.3–m resolution and a broader spectral range. moreover, china’s launch of highresolution remote sensing satellites, such as gf_1, gf_2, resource 2, resource 3, tiantu 1, and tiantu 2, has pushed the technology and its applications to new heights, including use in the detection of mineral deposits (chen et al., 2012; zhang et al., 2015; yang & zhao, 2015). geological deposits contain different mineral and chemical compositions to their surrounding rocks, and these differences are often reflected in remote sensing images in the form of spectral anomaly information. in this regard, a series of remote sensing digital image processes becomes application of high-resolution remote sensing technology for the iron ore deposits of the west kunlun mountains in china yuhai fan1,2,3,*, hui wang1,*, xingke yang3, guofeng zhang4, zhaoyang li1, furong tan1, shaopeng zhang1,2 and wenbo wang1 1 geological exploration institute of aerial photogrammetry and remote sensing bureau, xi’an,710199 china; (*corresponding author: 170269854@qq.com / wanghui.rock@163.com) 2 yulin university, school of management, yulin, 719000 china 3 chang’an university, school of earth science and land and resources, xi’an, 710054 china 4 inner mongolia mining exploitation co.ltd, hohhot, 010051 china doi: 10.4154/gc.2021.03 abstract this study focuses on the iron ore of taxkorgan and heiqia in the west kunlun mountains as a case study, for the application of worldview−2 and ikonos remote sensing images as major data sources in the fabrication of a standard image map and in the adoption of image enhancement methods to extract information on the ore-controlling factors and mineralization, to interpret remote sensing for the mineral resources in these areas. aster, worldview−2, and ikonos data were applied for the extraction of alteration anomaly information. with an appropriate amount of field sampling and verification tests, this was used to establish a remote sensing geology prospecting model, that would provide the basis for future remote sensing of metalloge nic belts in west kunlun in the hope of discovering similar minerals. survey results showed four additional iron ore mineralization belts could be delineated in the taxkorgan area. a comparative analysis conducted for part of the field confirmation and the known mineral deposits indicated good reliability. in heiqia, a siderite-haematite mineralization zone was observed with copperlead-zinc formation, 60-km in length and 200–500 m wide, which includes several mineralized bodies. the ore bodies, appear as stratoid, lenticular, or podiform morphologies and were located in the transition site from clastic to carbonate rocks of the d segment in the wenquangou group. the ore bodies generally occur within 40°–50° strike and 68°–81° dip, in accordance to the strata. the length of the single body varies from several hundred metres to more than 9500 m. its exposed thickness on the surface ranges from 2–50 m, and the general thickness was approximately 15 m. the surface ore minerals were mainly haematite and limonite, with a small amount of siderite. therefore, high-resolution remote sensing technology is suitable for iron ore geological and mineral remote sensing surveying. it is advantageous in both high-ground resolution of optical characteristics and a certain spectral recognition capability, and is effective not only for information extraction from a large area, but also for recognition of local mineralization outcrops. therefore, high-resolution remote sensing technology is valuable for popularization. an effective, prospective means of acquiring the geological anoma ly information related closely to ore-bearing strata, mineralized alteration zones, contact metamorphic zones, and tectonic zones (shang, 2009; wang et al., 2011; chen et al., 2012; jin et al., 2014; zhang et al., 2015; yang & zhao, 2015; howari et al., 2019; fan et al., 2021). located at the junction of the palaeo–asian and tethyan tectonic domains, west kunlun is an important part of the qin–qi– kun tectonic belt of china, and also serves as an important area for studying the evolution of the tethyan ocean (pan,1989, 1994, 1999; jiang & zhu, 1992; cheng, 1994; jiang & zhu, 1992, 2002; yang, 1994; pan et al., 1995; pan et al., 1996; cui et al., 2006; wu et al., 2008; wang et al., 2013; li et al, 2011. li, 2015; meng et al., 2019). west kunlun is characterized by strata exposed from palaeoproterozoic to mesozoic age (wang h et al., 2016; zhao et al., 2010), by strong folds and faults (wu et al., 2008), and by the experience of multistage and various types of tectonic events (lu et al., 2003; yang et al., 2004; xu et al., 2004; li et al., 2008), or geological events in different periods that are superimposed on each other, such as multistage magmatism and multistage metamorphism with complex magarticle history: manuscript received may 09, 2019 revised manuscript accepted february 03, 2021 available online february 28, 2021 keywords: remote sensing technology, iron ore deposits, geological survey, taxkorgan and heiqia area, west kunlun mailto:wanghui.rock@163.com g eo lo gi a c ro at ic a geologia croatica 74/158 matic (gao et al., 2013; zhao & liu, 2014; kang et al., 2015; yun et al., 2015), sedimentary (yao et al., 2006; li et al., 2007; zong et al., 2010), and metamorphic formations (jiang et al., 1992; pan, 1994; yang, 1994; li et al., 2008, 2011). thus, the strata, structure, metamorphism, magmatic activity, and other metallogenic geological conditions in the area are clear, with different types of deposits being discovered, together with good mineral prospects (bureau of geology and mineral resources of xinjiang, 1993; sun et al., 1997; jia, 1999; wang et al., 2000; dong et al., 2003; xi’an institute of geology and mineral resources, 2006; wang et al., 2006; chen et al., 2007; hou et al., 2008). despite such advantages, west kunlun remains an area with the lowest degree of geological and mineral research of china’s orogenic belt, due mainly to its cold and anoxic climate, strong topographic dissection, steep terrain, sparse population, and inconvenient transport network (yang, 1994; li et al., 2011, li, 2015). nonetheless, its sparse vegetation and exposed bedrock make it a suitable target for the development of high-resolution remote sensing techno logy (wang et al., 2011; chen et al., 2012; jin et al., 2014; yang & zhao, 2015). an important mineral for economic development is iron ore, formed through various processes including sedimentary metamorphism, magma, contact metasomatism-hydrothermal, volcanism, sedimentary deposition, and weathering (garašić & jurković, 2012; jurković & hrvatović, 2014; jelenković, 2016; wang et al., 2018). west kunlun’s iron polymetallic ore belt includes features of a large number of deposits, large-scale, and associated polymetallic mineralization that have attracted geological research both locally and internationally (feng et al., 2011; qiao et al., 2015, 2016; wang h., 2016; li et al., 2010). after years of field work, the present author has discovered magnetite deposits, such as laohe and zankan, in the bulunkuole group of the palaeoproterozoic in the taxkorgan area, along with the haematite-pinerite containing copper, lead, and zinc, in the wenquangou group of lower silurian age in the heiqia area (wang h., 2016). the iron ore of taxkorgan and heiqia in the mountains of west kunlun is used herein as a case study and a major data source for worldview–2 and ikonos remote sensing images, in the fabrication of a standard image map and adoption of methods of image enhancement so as to extract information on ore-controlling factors and mineralization via interpretation of the remotely–sensed mineral resources. data provided by aster, worldview–2, and ikonos are exploited for the extraction of alteration anomaly information. a remote sensing geology prospecting model is established with an appropriate amount of field sampling and a verification test, to provide the basis for future remote sensing on the metallogenic belt of west kunlun, in the prospect of discovering similar mineral deposits. 2. geological framework the study area spans the mountains of kunlun and karakorum, at the junction of the palaeo–asian and tethys tectonic (kunnan–yubei suture zone) domains; geographical coordinates e75°15′–79°15′, n35°30 ‘–37°40’ (li et al., 2013; wang et al., 2015; liu et al., 2015; qin et al., 2018; hou et al., 2018; yang, 1994; pan et al., 1996; wu et al., 2008). the metallogenic belts are ⅲ−1− moustag−aksai chin (terrigenous basin) fe−cu−au−pb−zn−rm metallogenic belt, and ⅲ−2− big hong liutan (terrigenous active zone) fe−rm−fe−pb−zn−cu metallogenic belt (pan, 1999; li, 2015; sun et al., 1997; bureau of geology and mine­ ral resources of xinjiang, 1993; dong et al., 2003; jia, 1999; wang et al., 2000) (fig. 1). figure 1. divisional map of the metallogenic belt in the study area. metallogenic belts: iii−1−①moustag−aksai chin (terrigenous basin) fe−cu−au−pb− zn−rm metallogenic belt; iii−2−① big hong liutan (terrigenous active zone) fe−rm−fe−pb−zn−cu metallogenic belt. g eologia c roatica fan et al.: application of high-resolution remote sensing technology for the iron ore deposits of the west kunlun mountains in china 59 2.1. geological characteristics of iron deposits of the taxkorgan area the taxkorgan area is bounded by the kangxiwa–muzitage– animaqing late palaeozoic junction belt, with the upper carboniferous (undivided) in the north, with a sporadic distribution of ordovician–silurian, and the widely exposed palaeoproterozoic brungula group in the south. the contact relationships between different strata are tectonic. magmatic activity is very strong and an intermediate-acid rock mass is widely distributed north of the junction zone. similarly, south of the junction zone, magmatic activity is frequent although there is less distribution of the intermediate-acid rock mass. relatively, there are strong folds and faults in the area, accompanied by an overall structural orientation to the nw. the strata exposed in this area mainly belong to a ferrosilicon formation of high green schist facies of the blenkole group in the palaeoproterozoic, distributed mainly in the in nw and see directions, and mostly in fault contact with the surrounding strata. metallogenic geological background: the study area was located in the taxkorgan landmass, with the junction zones of taasi–sekblak and kangxiwa–wacha as north and south boundaries, respectively. the outcropping strata belong to the brungula group of palaeoproterozoic age (pt1b). faults and folds were well developed in the area. the dominant structural orientation was nw, consistent with the strike of the north-south boundary faults. magmatic activity existed from the proterozoic–to–himalayan tectonic movement. ultrabasic to acidic magmatic rocks were exposed, of which intermediate-acidic granite and granodiorite were dominant during the yanshanian tectonic movements (yan et al., 2012; wand, j.f. ,2013; wang et al., 2013; wang et al., 2017). mining stratum: magnetite was localized in the iron-bearing section of the brongol group (pt1b). the main lithology was (iron­stained) biotite quartz schist, followed by (including magnetite?) gneiss with hornblende and biotite, magnetite quartz schist, two mica quartz schist, sericite quartz schist with magnefigure 2. the distribution of typical ore deposits and ore (chemical) locations of the heiqia polymetallic mineralization zone. g eo lo gi a c ro at ic a geologia croatica 74/160 tite, a small number of oblique long­angle flash schist (gneiss), chlorite schist, and marble (wang, et al., 2013; wang et al., 2017). ore body characteristics: most magnetite ores were ferrous black and gray-black, irregular (thick, massive, layered and lenticular) bodies. the occurrence of the ore bodies was similar to those of the roof and floor wall rocks, striking nw­se and dipping ne. the surface was layered, banded, and irregularly distributed. the lithology of the roof was mostly (iron-stained) black cloud quartz schist (wang et al., 2013; wang et al., 2017). wall rock alteration: the altered minerals of the wall rocks were mainly recrystallization of carbonates, actinolitization, chloritization, sericitization, limonitization / magnetitization, and so on (wang et al., 2013; wang et al., 2017). ore characteristics: the ore texture was mainly allotriomorphic to hipidiomorphic, idiomorphic to hipidiomorphic, cyclopean granular, lepidoblastic, and cataclastic, whereas its structure was mainly disseminated, massive, and banded. ore minerals in the area mainly include magnetite, haematite, pyrite, and limonite (wang et al., 2017). ore grade: the average ore grade was tfe 37.3%–58.69%, sio2 10.33%–30.27%, s < 0.08%, p2o5 < 0.21%. black magnetite was often accompanied by rare elements, such as vanadium and titanium (wang et al., 2017). 2.2. geological characteristics of iron-polymetallic mineralization belt of heiqia the iron­polymetallic mineralization belt of heiqia is located in the d formation of the wenquangou group of early silurian age (s1wd), whereas its northeast side is a formation of the huangyanling group from the early middle permian (pha) along the karatag fault boundary. the lithology of s1wd is composed mainly of cinerous-gray sandy slate with argillaceous slate and metamorphic sandstone; the top contains several layers of carbonate rocks, such as dolomite, iron dolomite, silicified dolomite, and a small amount of limestone (locally marbled) with siderite. in contrast, the lithology of pha is characterized by gray-black carbonaceous slate or spotted (pyrite-phenocryst) slate. it was truncated northward by the kangxiwa fault and extended southeastward beyond the zone for approximately 60-km. many new metallogenic clues (7 mineralization points in the northwest section and 3 mineralization points in the southeast section) have been discovered in the belt through geochemical surveying of stream sediments, remote sensing anomaly verification, and detailed surface tracing, together with an exploration trench-revealing project (fig. 2). 3. key technologies and methods the worldview–2 satellite could provide an 8 band, 1.84–m reso­ lution, multispectral image and 0.46–m panchromatic image, with 4 industry standard bands (red, green, blue, near-infrared) and 4 additional bands (blue indigo, yellow, red edge, near-infrared 2). its diverse spectrum contains abundant spectral information (0.400–1.040 um), while its extremely high spatial resolution can accurately reflect the structure, shape, texture, and other characteristics of objects; thus, the worldview–2 satellite is a fine data source for geological remote sensing (zhu, 2003; jin et al., 2013). the worldview–2 remote sensing image data used in this paper was from may 2010. the ikonos satellite, manufactured by lockheed martin, could collect 1–m resolution full colour and 4–m resolution multispectral images; the full colour and multispectral images could be blended into the 1–m resolution colour images. in this paper, the ikonos remote sensing image data used was from june 2010. aster is a multispectral imager mounted on the terra satellite, the received information of which includes the spectral reflectance of the ground in the vnir (visible and near­infrared) and swir (thermal infrared) bands, and thermal radiation of the ground in the tir range (thermal infrared). due to the wide wavelength range, several bands, and reasonable cost performance for the data, aster is widely used in extracting remote sensing (mineralization) alteration anomaly information (zhang et al., 2006). the high spatial resolution data of worldview–2 and ikonos were taken as the main information sources to establish standard remote sensing image maps through image preprocessing, geometric correction, image fusion, image enhancement, and image mosaic. on this basis, image enhancement was processed by band combination transform, principal component transform information decomposition, multiple principal component analysis (pca), and differential stretching. 3.1. production of standard remote sensing images according to the principle of band selection, the bigger the variance of band radiation and the smaller the band correlation is, the better. through calculation of the best index, or optimum index factor for b8 (r) b4 (g) b3 (b) of worldview–2, and b3 (r) b2 (g) b1 (b) and b4 (r)b2 (g) b1 (b) of ikonos, image fusion was performed using intensity-hue-saturation (ihs) transform, principal component transform, and pansharp. afterwards, a 1:50000 topographic map and digital elevation model (dem) data were used for selecting the rational polynomial coefficient parame­ ter correction model to carry out orthorectification and cubic convolution resampling. finally, the inlay mosaic method was used to create an image mosaic, and the base image for remote sensing interpretation was produced. 3.2. key methods of image enhancement processing 3.2.1. recognition of lithologic information by band combination transformation the characteristics of different lithologies that correspond to the absorption/reflection bands of worldview–2 and ikonos were applied into a series of band algebra operations to enhance the lithological information. for example, a combination of band8, band4/band1, and band5/band3 from the worldview–2 data facilitated identification of diorite, marble, and schist, or highlight the different lithological differences and improve the accuracy of lithological interpretations (fig. 3a). 3.2.2. recognition of lithological information by information decomposition technology of principal component transform the information of 532 and 681 principal component transformation was decomposed to fuse the two results and obtain a new image. it contains multiple bands of information and makes the correlation of different bands smaller, thus, enhancing the contrast between the different lithologies. for example, the different mineral contents of iron oxide, biotite, muscovite, feldspar, and quartz in schist yielded strip­like patterns of different tones, of which the orange-red tone with high iron content was either a magnetite­bearing quartz schist or a magnetite belt (fig. 3b). g eologia c roatica fan et al.: application of high-resolution remote sensing technology for the iron ore deposits of the west kunlun mountains in china 61 3.2.3. multiplex principal component analysis pca, band difference, ratio, and the like were used for the extraction of weak geological information in the image, and further, extraction of the most abundant combination of information, secondary processing, or selection of the most favorable result on the thematic information. specifically, pca was repeated for the last two objectives and the geological information was enhanced twice. 3.2.4. differential stretching initially, the high-resolution remote sensing image of worldview–2 did not show considerable distinction between the diffe­ rent lithologies, such as whether phyllite and metasandstone were of light blue appearance. upon application of differential stretching, the distinction became clear, such as the phyllite being light blue and the sandstone being white. 3.3. remote sensing mineralization anomaly information extraction 3.3.1. extraction of information of mineralization and alteration based on aster several methods can be used to perform extraction of anomaly information in remote sensing (mineralization) alteration, including pca, ratio analysis, and spectral angle analysis. if the principle considers large-scale ore (often containing high-value anomaly) as a main objective, pca is the primary choice. thus, iron staining, hydroxyl, and carbonate anomalies were extracted by principal component transformation, considering the relationship between the absorption spectra of various anomalies and the aster band. the main minerals in the area were sedimentary metamorphic magnetite, and the iron stain abnormality was the most direct remote sensing anomaly information with the iron ore. nonetheless, the relationship between hydroxyl and carbona te anomalies was less related to the iron ore, providing the basis for a focused discussion on iron-stained remote sensing anomaly extraction herein. fe2+ generated a strong and broad band at approximately 1.0–1.1 μm, whereas fe3+ exhibited strong absorption at 0.45, 0.55, 0.85, 0.90, and 0.94 μm, specifically indicating a strong absorption band between 0.9–1.0μm and a relatively strong reflection between 0.6–0.8 μm. according to the relationship between the abnormal absorption spectrum of iron staining and the aster data band (table 1), the iron stain information was reflected mainly in b1 to b4 bands, with strong absorption in b1 and b3, and strong reflection in b2 and b4. iron alteration information (fca) extraction: principal component transformation was performed for b1, b2, b3, and b4 bands of the aster data, with the mean + 4 s (standard deviation) as the dynamic range of the principal component output. the iron dye information was absorbed in aster data bands 1 and 3 and reflected in bands 2 and 4, thereby, the eigenvectors of the anomalous principal components were characterized by the opposite sign of the contribution coefficients of bands 1 and 3 and bands 2 and 4. after the principal components of 1, 2, 3, and 4 were transformed to obtain the feature matrix (table 2), the fourth principal component band 2 was opposite the band 1 and band 3 symbols, but was the same as the band 4 symbol, and therefore, could be used as the main component of the iron-staining anomaly. 3.3.2. extraction of information of mineralization and alteration based on worldview–2 the centres of the unusual absorption spectra of iron staining were 0.45, 0.55, 0.85, and 0.90 μm, corresponding to b1, b2, b3, b7, and b8 of the worldview–2 data. accordingly, the reflective characteristic spectra were within 0.60–0.80 μm, corresponding to b4, b5, and b6 of the worldview–2 data, of which, b1 and b8 showed strong absorption while b4 showed strong reflection. as a method of orthogonally transforming several specific bands, pca could be employed to remove the correlation between bands figure 3. effects of image enhancement: (a) ratio method to enhance lithology information; (b) principal component transform to enhance lithology information. table 1. abnormal absorption band of iron, hydroxyl and carbonates. ion, perssad absorption spectrum/µm aster band typical minerals fe2+, fe3+ fe2+:1.10~2.40 fe3+:0.45, 0.55, 0.85, 0.90, 0.94 band1, band3 limonite, hematite, goethite, jarosite and magnetite table 2. feature matrix of principle component transform (b1, b2, b3, b4). feature vector band 1 band 2 band 3 band 4 pc1 0.39 0.48 0.53 0.59 pc2 0.52 0.34 0.16 –0.77 pc3 0.68 –0.14 –0.67 0.26 pc4 0.33 –0.80 0.50 –0.02 g eo lo gi a c ro at ic a geologia croatica 74/162 and reduce the dimension of data, for concentration of as much useful information as possible, into a small number of band images. in pca, each principal component often represents a certain unique geological significance. after the principal components b1, b4, b6, and b8 of the worldview–2 data were transformed to obtain the feature matrix (table 3), the coefficient of b4 was found opposite to the coefficient of b1 and b8, but was the same as the b6 coefficient, and therefore, could be used as a principal component of the ironstaining anomaly. in this study, pca was applied for extraction of the iron ore mineralization (iron staining) remote sensing anomaly information. pc3 was the characteristic principal component of such an anomaly, in which the low-value area became the high-value area of the anomaly. the lower limit of abnormality was determined according to the mean +3δ (standard deviation), with the apparent extracted iron staining anomaly and higher degree of coincidence with the known iron ore body (fig. 4). 3.3.3. extraction of information of mineralization and alteration based on ikonos the centres of absorption spectra of iron staining were 0.45, 0.55, 0.85 and 0.90 μm, corresponding to b1 of the ikonos data. figure 4. worldview–2 anomaly extraction of iron ore of the taxkorgan area ((a) high–resolution image of the ore body; (b) iron alteration anomaly). table 3. the matrix of ferric contamination anomaly. feature vector band 1 band 4 band 8 band 6 pc 1 0.276 0.548 0.545 0.572 pc 2 0.813 0.234 –0.520 –0.120 pc 3 0.508 –0.590 0.582 –0.234 pc 4 0.076 –0.545 –0.306 0.777 table 4. the matrix of ferric contamination anomaly. feature vector b1 b3 b4 b2 pc1 0.383 0.549 0.505 0.544 pc2 –0.704 0.270 0.578 –0.313 pc3 –0.571 0.268 –0.499 0.594 pc4 0.178 0.744 –0.403 –0.503 figure 5. ferric contamination anomaly of ikonos remote sensing data in heiqia (photos of the iron field in the upper–right corner). g eologia c roatica fan et al.: application of high-resolution remote sensing technology for the iron ore deposits of the west kunlun mountains in china 63 accordingly, the reflective characteristic spectra were within 0.60–0.80μm, corresponding to b3 of the ikonos data. after the principal components b1, b3, b4, and b2 were transformed to obtain the feature matrix (table 4), the coefficient of b3 was found opposite those of b1 and b4, but was the same as the b2 coefficient, and, therefore, could be used as the principal component of the iron-staining anomaly. the lower limit of abnormality was determined according to the mean +3δ (standard deviation), with the banded extracted iron staining anomaly (fig. 5). 4. remote sensing geological characteristics 4.1. remote sensing geological characteristics of iron ore in the taxkorgan area the worldview–2 data were combined with the b8 (r) b4 (g) b3 (b) band, whereas the dem data were employed for orthorectification. a full colour band fusion process was used to achieve a 0.46–m fusion image resolution, later enhanced and transformed to highlight the lithology, structure, and iron ore (body) information. 4.1.1. stratigraphic lithology within the study area, magnetite was localized in the iron-bearing section of the brongol group (pt1b). the main lithology included (iron­stained) biotite quartz schist, followed by gneiss with hornblende and biotite, magnetite quartz schist, two mica quartz schist, sericite quartz schist with magnetite, a small number of gneiss with plagioclase and hornblende, chlorite schist, and marble. on the combined image of b8 (r) b4 (g) b3 (b) band from the worldview–2 data, biotite quartz schist was dark gray-black with a striped pattern and medium weathering resistance, and mostly formed a gentle slope microtopography that was most closely related to the magnetite space, as the wall rock of the ore body (fig. 6a). biotite plagioclase gneiss (including magnetites?) was dark gray to dark gray in tone with a striped pattern and strong weathering resistance, and mostly formed a striped steep ridge microtopography that was closely related to the magnetite space as the important ore hosting wall rock. moreover, magnetite quartz schist was gray­gray in tone with a narrow strip-like pattern and strong weathering resistance, and mostly formed a normal topography that was closely related to the magnetite space, often located in the magnetite mineralization zone. the dimica quartz schist was bright gray to dark gray or variegated tones with a banded pattern and medium weathering resistance, and mostly formed a gentle slope microtopography. sericite quartz schist was bright gray­white tones with a fine striped pattern and medium weathering resistance, and mostly formed a similar gentle slope microtopography. plagioclase amphibolite schist (gneiss) was dark gray-dark gray-greengray-black tones with a dark tone, banded or massive schistosomiasis, weak or non-schistosomiasis. chlorite schist was dark gray­green to dark gray in tone, with fine strip­like patterns and weak weathering resistance, and mostly formed gentle slopes or negative topographic micro-landforms. marble was bright grayyellow to gray-white in colour, with banded and irregular blocklike patterns and strong weathering resistance, and was generally dominated by a normal topography (fig. 6b). 4.1.2. structure the study area was located in the taxkorgan landmass, with the taasi–sekblak and kangxiwa–wacha junction zones as the northern and southern boundaries, respectively. faults and folds were well developed in the area, at a nw dominant structural orientation, consistent with the strike of the north-south bounda ry faults. most of the faults were compressive (torsional) structures. the image showed apparent linear structural features, which could form linear tone shadow abnormal zones and a linear negative topography. moreover, hues and textures on both sides of the fracture were significantly different, often forming dif­ ferent image volume boundaries (fig. 7a). some magnetite bodies in the area were reformed by secondary fracture structures, as manifested in two situations. first, under the influence of hydrothermal fluid (> 300 ℃), the thickness of the ore body increased and its grade became rich. second, under no hydrothermal coordination or low hydrothermal temperature (< 300 ℃), the ore fabric changed, mostly in the form of fragmentation and breccia, and the ore body continuity was destroyed to varying degrees. the fold structure showed the same set of banded image bodies on the image map, or an image marker layer with mirror symmetry and repeated distribution in space, continuous along the upwardly-inclined or back–tilted end. such distinct features were easily identifiable (fig. 7b). as an integral part of the stratum, the iron ore body was deformed synchronously with figure 6. image features of (a) quartz schist and (b) marble in taxkorgan. g eo lo gi a c ro at ic a geologia croatica 74/164 the ore-bearing surrounding rock, under the action of longitudinal bending and folding. additionally, under the action of flattening, the thickness of the wing ore body was reduced while that of the turning end body was increased. 4.1.3 ore body, mineralized zone the field observation results indicated that most magnetite ores are ferrous black and gray-black and have irregular (thick, massive, layered, and lenticular) bodies. specifically, the occurrence figure 7. remote sensing image features of the tectonic belt in taxkorgan ((a) tectonic belt of taaxi–sekebulake and (b) complex structure of jiertieke). figure 8. remote sensing image features of iron ore bodies in taxkorgan ((a) quickbird; (b) laobing iron mine; (c) worldview–2 and; (d) zoukebengou iron mine). g eologia c roatica fan et al.: application of high-resolution remote sensing technology for the iron ore deposits of the west kunlun mountains in china 65 of the ore bodies was similar to those of the roof and floor wall rocks. the ore hosting rocks were mainly biotite quartz schist, followed by biotite plagioclase gneiss, magnetite quartz schist, and quartz schist. in the laobing area, the iron ore bodies were patchy (dotted), beaded, and distributed intermittently along the foliation direction (fig. 8b). here, magnetite was a bright orange­ yellow­hue on the b8(r)b4(g)b3(b) band, combined with a high­score image of quickbird (fig. 8a). the kebengou iron ore belt with good continuity was distributed in regular strips ( fig. 8d). due to differences in surface scale, occurrence, and outcropping degree of the iron ore bodies, their shape and shadow structures were also different. 4.1.4. iron ore belt distribution along the area of ore concentration based on the extracted remote sensing (mineralization) alteration information and remote sensing interpretation of the main ore controlling elements, the distribution of mineralization zones in the iron ore belt was preliminarily obtained through a comprehensive remote sensing interpretation of their lithology, structure, intrusive rocks, ore bodies, and mineralization zones in the area of ore concentration. specifically, the iron ore (mineralization) zones in the study area were distributed as follows (fig. 9): (1) the zankan iron ore (mineralization) belt extends 5 km nw to se, from the mokart snow mountain (pl. 1a, b). the laohe–yelite– taasi iron ore (mineralization) belt extends over a 21-km-long and 1–2-km–wide nw–se distribution. there were 2 to 4 mineral veins in this belt, occurring as stratified or stratoid in form (pl. 1c, d; fig.8b). similarly, the zoukeben–taaxi iron ore deposit (mine­ ralization) belt lies along a nw–se distribution that extends to 18 km and that occurs as discontinuous stratified, stratoid, or lenticular morphologies (fig. 8d). moreover, the yukuli kukat iron ore (mineralization) belt in the northern maryang ocean extended approximately east–west, over a 2km distance. figure 9. sketch map of the iron ore, or mineralized zone in the concentration area. g eo lo gi a c ro at ic a geologia croatica 74/166 4.2. remote sensing characteristics of the heiqia iron polymetallic mineralization zone 4.2.1. remote sensing image interpretation markers the iron polymetallic mineralization zone of heiqia in the high­ resolution remote sensing images of ikonos (band combination b3 (r) b2 (g) b1 (b)) showed a light brown banded pattern, which was slightly different from the image characteristics of the two sides of the rock layer (fig. 10a). in the false-colour synthetic image of the enhanced thematic mapper (etm; band combination b7(r) b4 (g) b3 (b)), the mineralized zone showed a yellow­green tone and regular strip pattern. on both sides of the rock strata, a blue stripe pattern was apparent; although the colour difference between these rocks was apparent and easily distinguished, the boundary was barely discernible (fig. 10b). the effect of remote sensing interpretation was enhanced by decorrelating the b3(r) b2 (g) b1 (b) band combination of the ikonos images. the iron polymetallic mineralization belt of heiqia was brown in varying depths and regular strip­like pattern in the enhanced image, which was apparently different from the image characteristics of the two lateral strata outside the belt. nonetheless, the boundary was clear and easily identifiable. iron ore bodies were located mostly in the middle and lower part of the mineralization zone, with dark reddish-brown tone, narrow strip, lenticular, beaded, and intermittent extension, whereas the boundary with the mineralization zone was clear. through detailed interpretation, the mineralized bodies were distributed mainly in the northwest part of the mineralized zone, although other areas were difficult to interpret due to the small-scale single mineralized bodies or the serious surface coverage. the tones of floor wall rocks were mainly dark gray­blue­ dark brown-black with banded shape, whereas the tones of roof wall rocks were light gray-white-light yellowish-brown with banded extension (fig. 11a). information decomposition based on the pca was the common method of enhancing the weak information of geological lithology. using the ikonos data in b1, b3, b4, and b2 bands for the pca, band 4 was combined with the original bands 1 and 3 to obtain a new image. the iron polymetallic mineralization belt of heiqia was a pink tone and banded shadow, obviously different from the image characteri­ stics of the surrounding rock (fig. 11b). 4.2.2. geological characteristics of the heiqia iron polymetallic mineralization zone 1. geological characteristics of the ore (mineralization) body in the study area the ore bodies are of irregular stratoid, lenticular, or podiform appearance, with a few veins having bedding or through the figure 10. interpretation key of the heiqia iron polymetallic mineralization zone in (a) ikonos and (b) etm remote sensing data. figure 11. interpretation key of heiqia iron polymetallic mineralization zone after enhancement processing of ikonos remote sensing data ((a) decorrelation analysis and (b) pca). g eologia c roatica fan et al.: application of high-resolution remote sensing technology for the iron ore deposits of the west kunlun mountains in china 67 strata, had a sudden change of relationship with the surrounding rocks. it has an inclination of 40°–50°and an angle of 68°–81°, consistent with the occurrence of the surrounding rocks. the length of a single ore body was typically tens to hundreds of metres, and its surface outcropping thickness was within tens of centimetres to several metres (table 5). the boundary between the ore body and the upper and lower footwall was distinctive. the surrounding rock was mainly iron (iron-containing) dolomite, followed by dolomitic limestone, silicified dolomite marble (mostly located in the ore body), and a small amount of other metamorphic clastic rocks (metamorphic sandstone and sandy slate). the wall rocks of the ore body roof were dolomite, iron dolomite, silicified dolomite, marble dolomite, (strip) marble, and a small amount of limestone. the wall rocks of the ore body floor were sandstone, metasandstone, sandy slate, and carbonate rock. 2. ore characteristics the surface iron ore minerals were mainly limonite, followed by haematite and a small amount of siderite. galena, blue copper ore, malachite (pl.2d), and occasional? sphalerite, antimony lead ore, white lead ore, and black lead ore, were found in the lead (copper, zinc) associated with the iron ore. gangue minerals included quartz, muscovite, iron dolomite, and barite, and occasionally graphite, tourmaline, apatite, among others. the iron ore structure was composed mainly of two types: fine grain and the medium grain coarse-grained (variable crystal). furthermore, the main iron ore structure was of four types: (a) a compact block (pl.2a) and (hidden) lamellar structure formed during the syndepositional period; (b) banded and wrinkled structures formed during the post-metamorphic stage; (c) veins, cavities, clusters, and breccia structures formed during hydrothermal superimposition in the late tectonic stage (pl.2b); and (d) honeycomb, earth like, colloidal, and tuberculous structures formed after weathering and leaching of the earth’s surface. galena, which forms in the cracked carbonate rocks of the roof of an iron ore body, was mainly of semi­ebony and fine­grained structure (pl.2c). moreover, it was filled with irregular structural fractures (pl.2e). likewise, fractured carbonate was filled with structural fractures (pl.2f), showing disseminated and membranous structures. the pb (zn) ore was closely related to the iron (iron–bearing) dolomite, whereas cu mineralization was related closely to dolomitic marble. table 5. basic characteristics of main ore (chemical) points of the heiqia polymetallic mineralization zone. position newly discovered mineralized point number of ore bodies ore body shape surface scale long × width/m metallogenic element grade /% main ore mineral northwest paragraph no. 1 lead (zinc) iron ore point 1 stratiform 175×(4–8) fe (51.03), pb (zn) hematite, limonite, galena and pyrite no. 2 iron ore point 1 stratiform 170×(2–3) fe (43.35) hematite, limonite no. 3 containing lead–zinc iron ore point 1 lentoid 40×(0.5–8) fe (33.10) hematite, limonite, galena no. 4 lead (zinc) iron ore 1 stringer of penetrating layer 30×(0.1–0.3) fe (32.65), pb (zn) hematite, limonite, galena no. 5 lead–zinc ore 1 stringer of bedding rock 30×0. 4 pb+zn (2.37) hematite, limonite, galena, sphalerite no. 6 containing lead–zinc iron ore point 1 stringer of bedding rock 150×0.74 fe (31.10), pb+zn (2.35) hematite, limonite, galena, sphalerite no. 7 copper ore 1 stringer of bedding rock 1700×(0.5–0.7) cu (0.86) malachite southeast paragraph no. 8 iron lead mineralization point 3 stringer of bedding rock ?×(2.0–20) fe (37.46), pb (0.24–1.13) no. 9 iron, copper and lead mineralization point 5 stringer of bedding rock 200×(1–5)–900×(1–5) cu (0.27–0.49), pb (0.69) malachite, hematite, limonite, pyrite, chalcopyrite, galena no. 10 iron ore point 1 stringer of bedding rock 300×6 fe (29.90) hematite, limonite table 6. remote sensing model of sedimentary metamorphic type magnetite deposits in the taxkorgan study area. position newly discovered mineralized point number of ore bodies ore body shape surface scale long × width/m metallogenic element grade /% main ore mineral northwest paragraph no. 1 lead (zinc) iron ore point 1 stratiform 175×(4–8) fe (51.03), pb (zn) hematite, limonite, galena and pyrite no. 2 iron ore point 1 stratiform 170×(2–3) fe (43.35) hematite, limonite no. 3 containing lead–zinc iron ore point 1 lentoid 40×(0.5–8) fe (33.10) hematite, limonite, galena no. 4 lead (zinc) iron ore 1 stringer of penetrating layer 30×(0.1–0.3) fe (32.65), pb (zn) hematite, limonite, galena no. 5 lead–zinc ore 1 stringer of bedding rock 30×0. 4 pb+zn (2.37) hematite, limonite, galena, sphalerite no. 6 containing lead–zinc iron ore point 1 stringer of bedding rock 150×0.74 fe (31.10), pb+zn (2.35) hematite, limonite, galena, sphalerite no. 7 copper ore 1 stringer of bedding rock 1700×(0.5–0.7) cu (0.86) malachite southeast paragraph no. 8 iron lead mineralization point 3 stringer of bedding rock ?×(2.0–20) fe (37.46), pb (0.24–1.13) no. 9 iron, copper and lead mineralization point 5 stringer of bedding rock 200×(1–5)–900×(1–5) cu (0.27–0.49), pb (0.69) malachite, hematite, limonite, pyrite, chalcopyrite, galena no. 10 iron ore point 1 stringer of bedding rock 300×6 fe (29.90) hematite, limonite g eo lo gi a c ro at ic a geologia croatica 74/168 3. ore grade the results of the surface sampling and laboratory test showed a total iron? (tfe) grade within the range of 29.90% to 51.03% and an average grade of 36.94%, whereas pb+zn in the lead–zinc ore body had a grade within 0.24% to 2.37%, and that of cu in the copper ore body was within 0.27% to 0.86%. 4. metallogenic regularity and zoning characteristics of the metallogenic elements the results of the systematic field investigation showed that the nw–se development of the iron ore bodies deteriorated gradually, and the surface thickness of the mineralized bodies decreased gradually, together with the strike extension length of the single ore bodies. spatially, the iron polymetallic mineralization zone was closely related to the carbonate rocks on the roof of the ore body. carbonate rocks were developed in all occurrences of the iron ore body, although its thickness often had insignificant or negative correlation with the thickness of the carbonate rocks. along the strike of the mineralization zone, metallogenic elements nw–se generally showed the zoning rule of pb-zn-cu elements. as the iron ore body’s thickness reduced, the pb content decreased gradually, while that of zn gradually increased. moreover, as the cu content increased in the pinch-out area of the iron ore bodies, the element’s independent ore bodies appeared. 5. remote sensing integrated prospecting model based on the analysis of the metallogenic geological characteristics of the taxkorgan and heiqia iron deposits, interpretation of high-resolution remote sensing of ore controlling elements, and extraction of anomalous information of remote sensing mineralization and alteration, a comprehensive remote sensing prospecting model based on high-resolution remote sensing images was established and supported by field validation and correction (table 6, table 7). 6. conclusions (1) worldview−2 and ikonos remote sensing images were used as major data sources for the creation of a standard image map and for the adoption of image enhancement methods to extable 7. remote sensing geology prospecting model of the heiqia iron polymetallic mineralization zone in west kunlun region. ore controlling factors prospecting model geological conditions geotectonic location rift tectonic environment of the taxkorgan block ore hosting strata formation of blungule group in paleoproterozoic (ferriferous section) metallogenic environment early shallow, semi–deep sea sedimentary environment, exhalative sedimentary metallogenic in the intermittent period of submarine volcanic activity, after mineralization by regional metamorphism and deformation transformation surrounding rocks of mineralized body main lithology of (iron–dyed) biotite quartz schist, followed by (including magnet) black cloud slant gneiss, magnetite quartz schist, two mica quartz schist, sericite quartz schist with magnetite, a small number of oblique long–angle flash schist (gneiss), chlorite schist, and marble ore controlling structure well developed faults and folds in the area; nw dominant structural orientation, which is consistent with the strike of the north–south boundary faults wall rocks near the ore altered minerals of wall rocks that are mainly marbleization, actinolitization, chloritization, sericitization, ferritization, among others criteria of field geological prospecting magnetite body of a strong weathering resistance and whose outcrop is the most direct prospecting indicator; ore body that is black and gray from a distance and brown sauce from a near view; pyrite components in the ores that are easily weathered to form jarosite and limonite remote sensing characteristics high–score image features ore bodies in the worldview–2 image have beige–yellowish–green tones, stretching intermittently in strips, pods, and beads remote sensing anomaly information iron alteration anomaly geological conditions geotectonic location northern margin of the qiangtang–tanggula block, south of kangxiwa–muzitage–animaqing late paleozoic junction belt ore hosting strata d formation of the wenquangou group in early silurian (s1wd) metallogenic environment located in fine clasolite and carbonate formations of littoral–shallow–shelf facies at the top of d formation of the wenquangou group in early silurian with stable horizons and obvious stratabound characteristics surrounding rocks of mineralized body wall rocks of the ore body roof such as dolomite, iron dolomite, silicified dolomite, marble dolomite, (strip) marble, and a small amount of limestone; wall rocks of the ore body floor such as sandstone, metasandstone, sandy slate and carbonate rock ore controlling structure secondary faults, structural fissures, and interlayer fracture zones of carbonate rocks associated with the karatag fault wall rocks near the ore surrounding rock alteration that is generally weak; sericitization, chloritization, carbonation, and silicification that are common only in the surrounding rocks with strong tectonic reformation in the latter stage; apparent malachitization, blue copper mineralization, or lead–zinc mineralization in the mineralization zone criteria of field geological prospecting an ore body closely related to the iron dolomite in space; iron dolomite that is dark–yellow brown after oxidation on the surface and is easily identifiable, which is a good prospecting indicator; exposure of the primary siderite on the surface, followed by its transformation into iron oxides, such as hematite and limonite under oxidation to form an “iron cap,” which can directly guide the search for the primary siderite remote sensing characteristics high–score image features mineralized zones turning brown in different depths and regular strip–like pattern, after decorrelation analysis and enhancement of the b3(r)b2(g)b1(b) band combination of ikonos; clear and easily identifiable boundary; iron ore bodies of dark reddish brown tone, narrow strip, lenticular, beaded, and intermittent extension, and whose boundary with the mineralization zone is clear; carbonate rocks of light gray–white–yellowish–brown tones with striped patterns remote sensing anomaly information iron alteration anomaly geophysical and geochemical anomaly information geophysical information showing magnetic anomalies and geochemical information showing comprehensive anomalies of elements, such as pb, zn, cu and au g eologia c roatica fan et al.: application of high-resolution remote sensing technology for the iron ore deposits of the west kunlun mountains in china 69 tract the information of ore-controlling factors and mineralization and to provide an interpretation of remote sensing for mineral resources. furthermore, aster, worldview–2, and ikonos data were utilized to carry out alteration anomaly information extraction. given appropriate amounts of field sampling and a verification test, large iron ore belts were discovered in the study areas of taxkorgan and heiqia. (2) pca was used for the extraction of iron–staining anomalies from the high­fraction data (worldview–2, ikonos). the results indicated that the high-fraction data contained abundant information, high spatial resolution, good effect, and high accuracy of remote sensing anomalies extraction. thus, it used to locate iron ore bodies worthy of extraction and has further applications. (3) high-resolution remote sensing technology is suitable in iron ore geological and mineral remote sensing surveys and is similarly advantageous in both high-ground resolution of optical characteristics and particular spectral recognition capability. moreover, it is effective not only for information extraction from a large area, but also for the recognition of local outcrops of mineralization. therefore, it shouble be extended to other regions. the rapidly developing remote sensing technology, coupled with the successful launch of domestic high–resolution and hyperspectral satellites, is expected to provide a prospecting effect and wider application prospects for the improved exploration of mineral resources. acknowledgement this paper is supported by china’s geological survey project “remote sensing geological survey of mineral resources in the west kunlun metallogenic belt” (no. 1212011120888), remote sensing interpretation and application of resources and environment satellite in “one belt and one road” (no.dd20160117), and national key basic research program of “973” project “sedimentary environment and large-scale mineralization in continental basin of giant sandstone uranium metallogenic belt in north of china” (2015cb453000). thanks to the anonymous reviewers and editors of tea fluksi, lidija galović and julie robson for their suggestions on the paper. references alijagić, j. & šajn, r. (2020): application and improvement of soil spatial distribution mapping using advanced modelling techniques.– geologia croatica, 73/1, 69–84. doi: 10.4154/gc.2020.01 bureau of geology and mineral resources of xinjiang autonomous region (1993): regional geology of xinjiang autonomous region.– beijing: geological publishing house, 1−841 (in chinese). chen, l., zhang, w., zhou, y., liu, w. & chen, w. (2012): application of high­ resolution remote sensing images to searching for sedimentary-metamorphic type iron deposits in the taxkorgan area, xinjiang.– geology and exploration, 48/5, 1039−1048 (in chinese with english abstract). chen, s.j., li, r.s., ji, w.h., zhao, z.m., meng, y. & shi, b.d. (2007): the deposition characteristics and tectono-plaeogeographic environment of kunlun orogenic belt in late devonian.– geotectonicaet metallogenia, 31/1, 44−51. (in chinese with english abstract). cheng, y.q. (1994): outline to the regional geology of china.– beijing: geological publishing house, 1−200 (in chinese). cui, j.t., bian, x.w., wang, j.c., yang, k.j., zhu, h.p. & zhang, j.l. (2006): discovery of an unconformity between the lower silurian and middle devonian in the tianshuihu area, southern kangxiwar, west kunlun, china.– geological bulletin of china, 25/12, 1437−1440 (in chinese with english abstract). dong, y.g., guo, k.y., xiao, h.l., zhang, c.l., wang, a.g. & zhao, y. (2003): ore prospects of the west kunlun area in western china.– geology in china, 30/2, 173−178 (in chinese with english abstract). fan, y., wang, h., yang, x., liang, m., pan, c., zhang, s., wang, w. & tan, f. (2021): application of airborne hyper-spectral survey system casi/sasi in the gold-silver-lead-zinc ore district of huaniushan, gansu, china.– geologia croatica, 74/1, 73–83, doi: 10.4154/gc.2021.04. feng, c.r., wu, h. c. & chen, y. (2011): geological characteristics and genesis of the zankan iron deposit in taxkorgan, xinjiang.– geotectonica et metallogenia, 35/3, 404–409. gao, x.f., xiao, p.x., kang, l., zhu, h.p., guo, l., xi, r. g. & dong, z.c. (2013): origin of the volcanic rocks from the ta’axi region, taxkorgan, xinjiang and its geological significance.– earth science – journal of china university of geosciences, 38/06, 1169−1182 (in chinese with english abstract). garašić, v. & jurković, i. (2012): geochemical characteristics of different iron ore types from the southern tomašica deposit, ljubija, nw bosnia.– geologia croatica, 65/2, 255–270. doi: 104154/gc.2012.16 geng, x.x.,yang, j.m., zhang, y.j. & yao, f.j.(2008): the application of aster remote sensing data for extraction of alteration anomalies information in shallow overburden area – a case study of the baoguto porphyry copper deposit intrusion in western junggar,xinjiang.– geological review, 54/ 2, 184–191. doi: 10.16509/j. georeview. 2008.02.015. hou, q., mou, c., wang, q. & tan, z. (2018): provenance and tectonic setting of the early and middle devonian xueshan formation, the north qilian belt, china.– geological journal, 53, 1404–1422. doi: 10.1002/gj.2963 hou, z.q., song, y.c., li, z., wang, z.l., yang, z.m., yang, z.s., liu, y.c., tian, s.h., he, l.q., chen, k.x., wang, f.c., zhao, c.x., xue, w.w. & lu, h.f. (2008): thrust­controlled sediments­hosted pb­zn­ag­cu deposits in aster and northern margins of tibetan orogenic belt: geological features and tectonic model.– mineral deposits, 27/2, 123−144 (in chinese with english abstract). howari, f.m., aydaroos, f.a., nazzal, y., iqbal, j. & bou orm, n. (2019): hyperspectroscopic and microtopographic analysesof salt crust forms on arid, silty clay loam desert soils.– geologia croatica., 72/1, 43–49. doi: 10.4154/gc.2019.01 jelenković, r., milovanović, d., koželj, d. & banješević, m. (2016): the mineral resources of the bor metallogenic zone: a review.– geologia croatica, 69/1, 143–155. doi: 10.4154/gc.2016.11 jia, q. (1999): massive sulfide copper deposits of west kunlun, xinjiang.– beijing: geological publishing house, 1–100 (in chinese). jiang, c.f. (2002): important geological problems and the research progress of the central orogenic belt.– regional geology of china, 21/z2, 453−455 (in chinese with english abstract). jiang c.f. & zhu s.n. (1992): introduction to tectonic migration theory.– acta geoscientica sinica, 25, 1−14 (in chinese with english abstract). jiang, c.f., yang, j.s. & feng, b.g. (1992): opening and closing structure of kunlun.– beijing: geological publishing house, 1992, 161−168 (in chinese). jin, j., tian, s.f., jiao, r.c. & gao, h. (2013): lithology identification with worldview–2 data based on spectral analysis of surface features: a case study of wulukesayi district in xinjiang.– geoscience, 27/2, 489–496. jin, m.s., wang, h., qiao, g.b. & zhang, s.p. (2014): the discovery of heiqia iron mineralization belt in west kunlun by high resolution remote sensing technology and its geological significance.– northwestern geology, 47/4, 221−226 (in chinese with english abstract). jurković, i. & hrvatović, h. (2014): geochemical characteristics and genesisof mačje jame and vranjski potok as­cu­bearing iron occurrences westand southwest of the town of busovača, mid–bosnian schist mountains (mbsm).– geologia croatica, 67/2, 145–161. doi: 10.4154/gc.2014.11 kang, l., xiao, p.x., gao, x.f., xi, r.g. & yang, z.c. (2015): neopaleozoic and mesozoic granitoid magmatism and tectonic evolution of the western west kunlun mountains.– geology in china, 42/3, 533−552 (in chinese with english abstract). li, b.q., yao, j.x., gao, l.d., bian, x.w., yin, z.y., cui, j.t. & chen, w.x. (2007): age and source regions of the wenquangou group in the mazhar–kangxi­ war area, west kunlun mountains.– geological bulletin of china, 26/4, 457−465 (in chinese with english abstract). li, f.m., pen, x.p. & zhang, q.j. (2010): mineralization pattern and characteristics of qirikeqi siderite deposit in west kunlun.– xinjiang geology, 28/3, 274–279 (in chinese with english abstract). li, t. & wang, z.x. (2006): transverse structure and model of fault slivers in the northern part of the tarim block.– geology in china, 33/1, 14−27 (in chinese with english abstract). li, w., dong, y., guo, a., liu, x. & zhou, d. (2013): chronology and tectonic significance of cenozoic faults in the liupanshan arcuate tectonic belt at the northeastern margin of the qinghai–tibet plateau.– journal of asian earth sciences, 73, 103–113. doi: 10.1016/j.jseaes.2013.04.026 li, w.y. (2015): metallogenic geological characteristics and newly discovered orebodies in northwest china.– geology in china, 42/3, 365−380 (in chinese with english abstract). li, w.y., zhang, z.w. & gao, y.b. (2008): the important mineralization events and tectonic response of qinling, qilian and kunlun orogenic belts [c]//chen yuchuan, xue chunji, zhang changqing. endeavoring deep marching west scaning world −symposium of the ninth mineral deposit conference in china.– beijing: geological publishing house, 15−16 (in chinese). g eo lo gi a c ro at ic a geologia croatica 74/170 li, w.y., zhang, z.w., gao, y.b., tan, w.j., jiang, h.b. & guo, z.p. (2011): important metallogenic events and tectonic response of qinling, qilian and kunlun orogenic belts.– geology in china, 38/5, 41–50 (in chinese with english abstract). liu, l., ya, b., lei, ly. & yang, q. (2015): early paleozoic granitic magmatism related to the processes from subduction to collision in south altyn, nw china.– science china earth sciences, 58, 1513–1522. doi: 10.1007/s11430­015­5151­1 lu, s.n., li, h.k. & chen, z.h. (2003): characteristics, sequence and ages of neoproterozoic thermo­tectonic events between tarim and yangzi blocks − a hypothe­ sis of yangzi −tarim connection.– earth science frontiers, 10/4, 321−326 (in chinese with english abstract). meng, y.k., xiong, f.h., xu, z.q. & ma, x.x. (2019): petrogenesis of late cretaceous mafic enclaves and their host granites in the nyemo region of southern tibet: implications for the tectonic–magmatic evolution of the central gangdese belt.– journal of asian earth sciences, 176, 27–41. doi: 10.1016/j.jseaes.2019.01.041 pan, y.s. (1989): tectonic division of kunlun mountain.– journal of natural resources, 4/3, 196−203 (in chinese with english abstract). pan, y.s. (1994): the discovery and demonstration of the fifth suture zone in qinghai− tibet plateau.– chinese journal of geophysics, 37/2, 184−192 (in chinese with english abstract). pan, y.s. (1999): the formation and uplifting of the qinghai tibet plateau.– earth science frontiers, 6/3, 153−163 (in chinese with english abstract). pan, y., yi, w., matte, p. & tapponnier, p. (1995): geology along the line from yecheng to shiquanhe and tectonic evolution of the region involved.– acta geo­ logica sinica, 8/2, 119−133. pan, y.s., zhou, w.m., xu, r.h., wang, a.d., zhang, y.q., xie, y.w., chen, t.e. & luo, h. (1996): early paleozoic geological features and evolution of the kunlun mountains.– science in china (ser. d), 26/4, 302−307 (in chinese) qiao, g.b., wang, p., wang, z.h., wu, y.z., wu, h.c., zhao, x.j. & chen, d.h. (2016): genesis of the qieliekeqi iron deposit in western kunlun: evidence from geological and geochemical characteristics.– acta geologica sinica, 90/10, 2830–2846. qiao, g.b., wang, p., wu, y.z., hao, y.h., zhao, x.j., chen, d.h., lu, p.r. & du, w. (2015): formation age of ore-bearing strata of the zankan iron deposit in taxkorgan landmass of western kunlun mountains and its geological significance.– geology in china, 42/3, 616–630 (in chinese with english abstract) qin, y., feng, q., chen, g., chen, y. & zou, k. (2018): devonian post–orogenic extension–related volcano–sedimentary rocks in the northern margin of the tibetan plateau, nw china: implications for the paleozoic tectonic transition in the north qaidam orogen.– journal of asian earth sciences, 156, 145–166. doi: 10.1016/j.jseaes.2018.01.009 shang, d. (2009): worldview−2 high resolution satellite launch successfully.– remote sensing for land & resources, 20/4, 109 (in chinese). sun, h.t., li, c.j., li, j.r. & wu, h. (1997): the ore­forming prospecting of copper deposit in kungaishan area of west kunlun, xinjiang.– geology in china, 24, 29−30 (in chinese with english abstract). wand, j.f. (2013): remote sensing study of metallogenic condition in west kunlun laobing–zankan ore concentration area.– northwestern geology, 46/2, 167–173. wang, c., liu, a., wang, h., he, sp., li, p. & rong, y. (2015): recognition and tectonic implications of an extensive neoproterozoic volcano–sedimentary rift basin along the southwestern margin of the tarim craton, northwestern china.– precambrian research, 257, 65–82. doi: 10.1016/j.precamres.2014.11.022 wang, c., liu, l., korhonen, fawna, yang, w. & cao, y. (2016): origins of early mesozoic granitoids and their enclaves from west kunlun, nw china: implications for evolving magmatism related to closure of the paleo–tethys ocean.– international journal of earth sciences, 105, 941–964. doi: 10.1007/s00531-0151220-0 wang, h., fan, y. h., yang, j.z., zhang, s.p., jin, m.s., yang, c., liang, m., cui, s., he, x.l. & pan, c.j. (2017): the application of high resolution remote sensing technology in the iron ore of taxkorgan area, west kunlun mountains.– northwestern geology, 50/2, 231–243 (in chinese with english abstract). wang, h., fan, y.h., zhang, s.p., jing, m.s., cui s., wang, w.b., yang, c., kuang, j.s. & guo p.c. (2016): delineation of heiqiairon polymetallic minera­ lization zone in west kunlun region by using high resolution remote sensing technology.– geological survey of china, 3/5, 13–20 (in chinese with english abstract). wang, r.s., xiong, s.q., nie, h.f., liang, s.n., qi, z.r., yang, j.z., yan, b.k., zhao, f.y., fan, j.h., ge, d.q., zhang, x.k., zhang, z.h., wang, p.q., guo, x.f. & li, l. (2011): remote sensing technology and its application in geological exploration.– acta geologica sinica, 85/11, 1699−1742 (in chinese with english abstract). wang, s.l., wang, d.b. & zhu, x.y. (2000): ore­searching prospecting analysis of gold(copper) deposits in the west kunlun.– contribution to geology and mineral resources research, 15/3, 224−229 (in chinese with english abstract). wang, x., zhang, x., gao, j., li, j. & jiang, t. (2018): a slab break­off model for the submarine volcanic-hosted iron mineralization in the chinese western tianshan: insights from paleozoic subduction-related to post-collisional magmatism.– ore geology reviews, 92, 144–160. doi: 10.1016/j.oregeorev.2017.11.015 wang, y., li, d.g., xiao, x.c., chi, z.q., min, l.r., wang, j. & wang, y.b. (2006): late cenozoic tectonic movement in the front of the west kunlun mountains and uplift of the northwestern margin of the qinghai− tibetan plateau.– geology in china, 33/1, 41−47 (in chinese with english abstract). wang, z., wang, j., du, q., deng, q. & yang, f. (2013): the evolution of the central yangtze block during early neoarchean time: evidence from geochronology and geochemistry.– journal of asian earth sciences, 77, 31–44. doi: 10.1016/j. jseaes.2013.08.013 wu, j.h. & liu, s.a. (2008): introduction to geotectonics and outline of chinese earth tectonics.– beijing: geological publishing house (in chinese). xi’an institute of geology and mineral resources (2006): the prospecting potential of mineral resources in northwest china.– beijing: geological publishing house, 1–150 (in chinese). xu, z.q., qi, x.x., liu, f.l., yang, j.s., wu, c.l., zeng, l.s. & liang, f.g. (2004): the kangxiwar caledonian khondalite series in west kunlun, china, and its geological significance.– acta geologica sinica, 78/6, 733−743 (in chinese with english abstract). yan, c.h., chen, c.j. & cao, x.z. (2012): the discovery of the “pamir­type” iron deposits in taxkorgan area of xinjiang and its geological significance.– geological bulletin of china, 31/4, 549–557. yang, j.s., wang, x.b., shi, r.d., xu, z.q. & wu, c.l. (2004): the dur’ngoi ophiolite in east kunlun, northern qinghai − tibet plateau: a fragment of paleo − tethyan oceanic crust.– geology in china, 31/3, 225−239 (in chinese with english abstract). yang, j.z. & zhao, y.l. (2015): technical features of remote sensing and its application in the geological survey and mineral resources survey.– mineral exploration, 6/5, 529−534 (in chinese with english abstract). yang, j.z., fang, h.b., zhang, y.j. & chen, w. (2003): remote sensing anomaly extraction in important metallogenic belts of western china.– remote sensing for land and resources, 15/3, 50−53 (in chinese with english abstract). yang, k.n. (1994): tectonic evolution of continental margin on the west kunlun and type of southwestern tarim basin.– geological review, 1, 9−18 (in chinese with english abstract). yao, j.x., xiao, x.c., gao, l.d., han, f.l., cui, j.t., peng, h.l., ji, z.s. & wu, c.c. (2006): silurian acritarchs and chitinozoans in wenquangou group from the west kunlun region.– acta palaeontologica sinica, 45/4, 528− 532 (in chinese with english abstract). yun, j., gao, x.f., xiao, p.x., kang, l. & li, p. (2015): geochemical characteristics of the lower carboniferous volcanic rocks of the wuluate formation in the western kunlun mountains and their geological significance.– geology in china, 42/3, 587−600 (in chinese with english abstract). zhang, c., peng, l.h., wang, b., zhang, e., fu, l.h., wei, b.z. & jie, w.h. (2015): application of worldview−2 remote sensing image in the exploration of the volcano–sedimentary metamorphic type iron deposits in the dimunalike area, xinjiang.– mineral exploration, 6/5, 523−528 (in chinese with english abstract). zhang, y.j., yang, j.m. & yao, f.j. (2006): the extraction of oha from different types of deposits by using aster data.– mineral deposits, 25 (supplement), 507–510. zhao, g., yin, c., guo, j., sun, c., sun, z. & li, s. (2010): metamorphism of the luliang amphibolite: implications for the tectonic evolution of the north china craton.– american journal of science, 310, 1480–1502. doi: 10.2475/10.2010.10 zhao, j.a. & liu, z.j. (2014): mesoproterozoic pashtok dioriteintrusive sequenceon the northern margin of west kunlun orogenic belt in xinj fang and its geological implications.– geology in china, 41/1, 92−107 (in chinese with english abstract). zhu, l.j., qin, q.m. & chen, s.j. (2003): the reading of aster data form file and the application of aster data.– remote sensing for land & resources, 56/2, 59–63. zong, w.m., gao, l.z., ding, x.z. & pang, w.h. (2010): characteristics of nanhuan diamictite (tillite) and stratigraphic correlation in the southwestern margin of tarim basin.– geology in china, 37/4, 1183−1190 (in chinese with english abstract). g eologia c roatica fan et al.: application of high-resolution remote sensing technology for the iron ore deposits of the west kunlun mountains in china 71 plate 1. field photography of the iron ore belt in taxkorgan. a jarosite on the surface of the zankan iron ore body; b zankan iron ore body outcrop; c laobing iron ore body outcrop and d yerite valley iron ore body outcrop. g eo lo gi a c ro at ic a geologia croatica 74/172 plate 2. field photography of the ore in heiqia. a massive and honeycombed limonite; b breccia limonite; c concretion forms limonite; d lead mineralization and malachite mineralization of ore; e vein lead–zinc ore in roof of iron ore and f azurite in marbleization dolomite of iron ore.  geologia croatica 65/3 299–322 26 figs. zagreb 2012 1. introduction the pennsylvanian was one of the most important times for coal formation in earth history. the lowland areas of eura­ merica and china were covered by extensive wetland forests dominated by arborescent lycopsids and tree ferns (op luš­ til & cleal, 2007). extensive floras are known from up­ per silesia, the intra sudetic basin, central and western bo­ hemia, south wales and from the pennines (for more details see opluštil & cleal, 2007). in italy (southern alps, tuscany, sardinia, liguria), se­ veral outcrops of terrestrial sediments have also yielded pennsylvanian floras. although the carboniferous sections are mostly scattered and of limited extent, these pennsylva­ nian occurrences are fundamental for regional correlations and palaeogeographic reconstructions. therefore the goal of this paper is to provide an updated review on the main sections which have yielded rich penn­ sylvanian plant megafossils and palynofloras, hoping that a future taxonomic revision of them can provide a better pic­ ture of the pennsylvanian floras of italy. 2. the major pennsylvanian floras in italy from northern to southern italy, the most important out­ crops are mainly concentrated in four different regions (fig. ab stra ct the paper provides an overview of the main pennsylvanian sites in italy yielding associations rich in plants and/or palynomorphs. so far in italy, the principal outcrops are located in the southern alps, tuscany and sardinia. in the western southern alps and bordering switzerland, westphalian outcrops are small and scattered. nevertheless, one of them yielded an abundant fossil flora, stored at the museo civico di storia naturale of milan, (venzo and maglia collection). in the carnic alps, (eastern southern alps), continental deposits of moscovian to gzhelian age also oc­ cur near the border with austria. they have produced a high number of preserved plant fossils, presently stored in the museo friulano di storia naturale of udine. in tuscany, the two main sections yielding westphalian to autunian floras are those of the iano and pisani mountains. a rich collection of plant fossils from those sites is hosted at the museo di storia naturale of florence university and at the museum of natural history of pisa university. in sar­ dinia, plant fossil sites are located in the south west and central east parts of the island. the san giorgio basin (igle­ siente subregion) and the tuppa niedda section (arburese subregion) are late westphalian – early stephanian in age. in the barbagia at seui­seulo and the gerrei subregions, other continental basins yielded transitional “stephanian­ autunian” fossil plant associations. the slabs are stored as part of the lovisato collection at the lovisato museum of the chemical and geoscience department of cagliari university. smaller historical outcrops of carboniferous age are also known from other italian regions, such as liguria. keywords: pennsylvanian, southern alps, tuscany, sardinia, plant fossils, palynomorphs, fossil plant collections geologia croaticageologia croatica pennsylvanian floras from italy: an overview of the main sites and historical collections  ausonio ronchi1, evelyn kustatscher2, paola pittau3 and giuseppe santi1 1dipartimento di scienze della terra e dell’ambiente, università di pavia; (ausonio.ronchi@unipv.it; gsanti@unipv.it) 2museo di scienze naturali dell’alto adige, bolzano; (evelyn.kustatscher@naturmuseum.it) 3dipartimento di scienze chimiche e geologiche, università degli studi di cagliari, italy; (pittaup@unica.it) doi: 104154/gc.2012.20 geologia croatica 65/3geologia croatica 300 1), excluding small and debated outcrops in western ligu­ ria. they are briefly described in paragraph 5 and synthe­ sized here below. 2.1. southern alps 2.1.1. western southern alps/canton ticino (switzerland) sparse continental pennsylvanian successions crop out in the western southern alps, especially in the so­called vare­ sotto­lugano area, to the west of lake como (fig. 2). the main localities are alpe logone, val rezzo, mesenzana, grantola, bèdero, bosco valtravaglia­fabiasco, val tresa on the italian side of the border and manno (and other small sections in val colla, cadro, denti della vecchia, etc.) in the canton ticino area (switzerland). the successions, called by many authors the “basal con­ glomerate”, are alternations of conglomerates, sandstones and siltstones composed of metamorphic and vein­type quartz clastics. these units were also name “non­porphyric” conglo­ merates (e.g., baggio & de marco, 1960), in order to distinguish them from younger deposits where volcano­clastic deposits occur. the bedding of these generally coarse­grained sediments is often irregular and some crude channelling is ob­ served. deposits occur generally pinched along major tectonic lines or in stratigraphic non­conformities above the metamor­ phic basement, and represent the “southern alps sedimentary front”. these sediments are the product of the erosion of the variscan mountain chain, and the contact with the crystalline figure 1: location of the main pennsylvanian sites in italy. 1 – western lombardy region and canton ticino (switzerland); 2 – carnic alps (alto adige and tyrol, austria); 3 – tuscany (pisani mountains and iano); 4 – south western, central and south eastern sardinia. figure 2: location of the main outcrops of pennsylvanian sections in the western southern alps and canton ticino (from pittau et al., 2008a, mod.) a – italian/swiss sector between lake maggiore and lake lugano; b – italian/swiss sector between lake lugano and lake como. bold line is the italianswiss border. ronchi et al.: pennsylvanian floras from italy: an overview of the main sites and historical collections geologia croatica 301 basement is marked by a gap of unknown time (bertotti, 1991). the thickness varies from 0–15 m in the val sanagra (venzo & maglia, 1947), to 20–30 m in the val rezzo (fig. 3) and in the upper val colla, and to about 100 m beneath the denti della vecchia (lehner, 1952). the finer grey­to­reddish clastic sediments structurally de­ veloped in a basin situated south of the marzio lineament, (or brusimpiano­cabiaglio lineament). they generically follow the initial deposition of volcanic­rich conglomerate, and are called the mesenzana formation (casati, 1978; see fig. 5). the age of all the upper palaeozoic, strongly tectoni­ cally stressed, sedimentary successions, scattered over a wide area between lake como, lake maggiore and ticino, has long been debated as being between the westphalian and stephanian (e.g. lehner, 1952; venzo & maglia, 1947; stadler et al., 1976; casati, 1978; gaetani et al., 1986). the whole region, where all these so­called “basal con­ glomerats” crop out, can be subdivided into two sectors (fig. 2) which, from e to w, are described below. figure 3: lithological and stratigraphic section south-east of cimadera-val rezzo (from lehner, 1952, mod.). the upper carboniferous (i.e. pennsylvanian) conglomerates and the overlying “verrucano-servino series” are tectonically separated by a thinband and of “gneiss chiari”. 1– dolostones, 2– micaceous, clayey sandstones, 3 – mainly quartzose sandstones, 4 – arkosic sandstones, 5 – conglomerate breccia, 6 – sandy dolostones and dolomitic sandstones, 7 – conglomerates, 8 – sandstones, 9 – coal bearing-sandstone, 10 – “gneiss chiari”, 11 – phyllonites. geologia croatica 65/3geologia croatica 302 sector b to the east, between the lugano and como lakes, some small outcrops with fine to coarse grained clastic deposits occur (fig. 2b), including alpe logone, which has yielded a rich macrofloral association. the first report on carbonife­ rous macrofloras from this locality is from magnani (1946), who discovered impressions and casts of calamites, sigillaria and lepidodendron. in the mid 20th century, silvio venzo and luigi maglia (venzo & maglia, 1947; venzo, 1951) collected more than 2000 leaf compressions and im­ pressions from the anthraciferous and silicified beds at alpe logone, (in the val sanagra and, particularly, in val ga rias ca). they described about 22 genera and 75 species belon ging to the sphenophyllaceae (sphenophyllum), equisetales (e.g., calamites, asterophyllites, annularia), lycopodiales (e.g., lepidodendron, knorria, lepidophyllum; sigillaria­ ceae, sigillaria, stigmaria; ulodendraceae), cycadaceae, cordaitales, filicales and pteridospermales (e.g., pecopteris, figure 4: some examples of plant fossils from the pennsylvanian of the alpe logone/val sanagra (w lombardy), from venzo collection hosted in milano museum (determinations by s. opluštil and j. pšenička). a. pecopteris (lobatopteris) cf. simoni (sample b1519); b. linopteris obliqua (sample b1605); c. paripteris linguaefolia (sample b1895); d. annularia radiata (sample b1888); e. bothrodendron sp. (sample b1686); f. sigillaria rugosa (sample b1722); g. alepthopteris cf. grandinioides var. grandinioides (sample b1902b). ronchi et al.: pennsylvanian floras from italy: an overview of the main sites and historical collections geologia croatica 303 mariopteris, neuropteris, linopteris). poorly preserved banded fragments of sigillaria were also reported from the arenaceous layers. the rich collection, housed in the museo civico di storia naturale of milan, is currently under revi­ sion (fig. 4). the flora was ascribed to the late westphalian (westpha­ lian c) by venzo & maglia (1947) and venzo (1951). these authors consider the flora of the alpe logone to be slightly older than the flora from the manno conglomerate in ticino (see below), even if both show close affinities. accor­ ding to pittau et al. (2008a), the very rich logone and man­ no’s macrofloristic assemblages allow assignment to the bol­ sovian (westphalian c) or to the duckmantian­bolsovian (westphalian b–c) transition. sector a to the west, between the maggiore and lugano lakes (fig. 2a), several small outcrops of the manno conglomerate are known. the type section crops out in the homonymous vil­ lage in ticino (switzerland). the fossiliferous successions are characterized by alternations of fine layered sandstones and conglomerates of light­grey colour. locally they bear anthracite­type rock layers with poorly preserved plant re­ mains. as in manno, these deposits occur in very scattered outcrops, generally pinched along tectonic lines. they rep­ resent the oldest sedimentary units in the western southern alps. the manno conglomerates likely filled a fault­bounded intracontinental basin characterized by fluviolacustrine and fluviopalustrine environments. these deposits represent the base of an initial tectono­sedimentary cycle developed mainly during the early to middle permian throughout the southern alpine domain (e.g., gaetani et al., 1986; cas­ sinis & perotti, 2007). from the manno type­locality, heer (1876) listed calamites cisti, sigillaria elongata and s. elegans. escher (1911), confirmed calamites cisti, and sigillaria elonga , but figure 5: a simplified geological map and section of the western southern alps (from casati, 1978, mod). this area relates generally to sector a shown in fig. 2. geologia croatica 65/3geologia croatica 304 attributed the last species to s. tessellata. sordelli (1896), recognized 13 species; ten are common with the flora from the alpe logone, including five species of sigillaria, and another five species among the genera calamites, lepidodendron and cordaites. he attributed the manno flora to the early stephanian, but with many westphalian elements (sordelli, 1896). venzo (1951) attributed the flora from manno to the transition between the westphalian b and westphalian c, suggesting it to be slightly older than the flora from alpe logone (see above). jongmans (1950), related the floras of various swiss localities (including manno), first to the westphalian b–c due to the presence of some elements such as linopteris neuropteroides, cf. pecopteridium, sigillariaephyllum, cordaites cf. borassifolius, but later considered it to be slightly younger, most likely west­ phalian (“mittleres westphalen”, jongmans, 1960, p. 95). along the germignaga­bèdero road on the eastern side of lake maggiore, some light grey coloured layers of sand­ stones and conglomerates also occur. locally, they bear an­ thracite with badly preserved plant remains including sigillaria, which is putatively attributed to the stephanian (venzo & maglia, 1947). clasts of this succession show an origin from the metamorphic basement alone, but at the top of the bèdero section, and in the very nearby outcrop, (i.e. along the luino­laveno railway­line), volcanic­rich conglomerates are also reported by these authors and thus suggesting a younger (permian?) age for these latter sedi­ ments (fig. 6). more recently, the bèdero section (lake maggiore, fig. 2a and fig. 7) yielded a rich palynoflora, which allowed as­ signment of these sediments to the late westphalian­early stephanian (pittau et al., 2008a). in the sporomorphs, 42 genera and 76 species with one new genus (cassinisporites) and ten new species have been distinguished. the bèdero assemblages are suggested as being younger than the suc­ cessions studied from north­eastern italy, and to be more or less of the same age as the flora of san giorgio (south­west­ ern sardinia). the dominance of trilete spores, with a pro­ nounced taxonomic diversity, and florinites pollen (over 70%), is indicative of a well­developed flora dominated by ferns, pteridosperms and cordaitales, typical of a lowland flora (pittau et al., 2008a). 2.1.2. eastern southern alps and border with austria (carnian alps) the carboniferous successions of the eastern southern alps crop out in several localities of the carnian alps, near the border with austria and in carinthia (fig. 8). they represent the lower part of the more than 200 metre­thick terrestrial­ transitional­marine permo­carboniferous sequence (fig. 9). from the 1970’s onwards, pennsylvanian plant mega­ fossils have been studied from several localities, mostly on the austrian side, (e.g., van amerom et al., 1976; van amerom & schoenlaub, 1992., fritz, 1980, 1983; fritz & boersma, 1983; fritz & kra iner, 1993, 1994, 1995, 1997, 2006; van amerom & kabon, 2000). nowadays, three different permo­carbo niferous basins are distinguished in the carnian alps, respectively around forni avoltri, pramollo and tarvisio (selli, 1963; venturini, 1983, 1990a, b, 1991; venturini et al., 1991). the pra mollo basin is the most important and extensive with several loca­ li ties (e.g., passo pramollo, cason di lanza, monte corona) yielding rich floras (fig. 10). this basin has been studied in detail with respect to its sedimentology, stratigraphy, petro­ graphy and palaeomagnetics (e.g., venturini, 1990a and ref. therein). the rich fossil content (brachiopods, crinoids, zoophycos, fusulinids, plants; fritz et al., 1990) has been used to constrain the age of the different formations and to figure 6: geological sketch sections of the pennsylvanian to ladi nian succession on the germignaga-bèdero road and railroad, near luino, lake maggiore (from venzo, 1950, mod). above: on the road to bèdero; below: on the lakeside road and between the railway tunnels “lunghi” and “lavello”. 1. basement micaschists; 2. pennsylvanian transgressive conglomerates and sandston es (stephanian); 3. reddish clayey sandstones (permi an?-scythian), 4. reddish porphyritic conglomera tes (late scythian); 5. dolostones (anisian -ladi nian); 6. talus. ronchi et al.: pennsylvanian floras from italy: an overview of the main sites and historical collections geologia croatica 305 reconstruct the evolution of the basin. the ichnoassemblages reflecting changes from terrestrial to lagoonal facies are also important (baucon & car valho, 2008). from base to top, the pramollo group (venturini, 2002a, b), formerly the auernig group sensu selli (1963; see fig. 9), is composed of the meledis, pizzul, corona, au­ ernig and carnizza formations. the pramollo group consists of cyclic, shallow­marine, clastic and carbonate deposits up to 1200 m thickness. shore­face and offshore environments are quite common. moreover, the regressive–transgressive cycles (“auernig cyclothems”), in the upper part of this group have been related to eustatic sea­level changes due to the permo­carboniferous glaciation, where the carbonatic levels would correspond to interglacial phases with a sea­level rise covering this area (venturini, 1990a, b; 1991; massari et al., 1991). the most abundant flora comes from the co­ rona formation (a3 formation sensu venturini, 1990a, b), a terrigenous succession of uppermost gzhelian age, (ma­ s sari et al. in venturini et al., 2002b). plant fossils are, however, widely distributed in most of the fine sandstones and pelites of the bombaso formation and basal pramollo group, (meledis, pizzul, basal auernig and car nizza forma­ figure 7: the bèdero section (from pittau et al., 2008a, mod). geologia croatica 65/3geologia croatica 306 tions, respectively a1, a2, a4 and a5 of venturini 1990a, b, see fig. 9). the corona formation is characterized by its almost complete lack of carbonatic levels (so far only one has been identified, see krainer in venturini, 1990b). it consists mainly of alternations of fine quartzose conglomerates, sand­ stones and siltstones corresponding to subaerial or paralic environments (venturini, 1990a, b). there also exist, two transgressional acmes with fine siltstone, hummocky structures and a high abundance of marine fauna (brachio­ pods, crinoids, marine ichnofossils). plant megafossils occur in the fine sandstones and pelitic levels (fig. 10), and several sphenophyte trunks have been found in situ (with a diameter of up to 20 cm). coal­rich levels of up to 30 cm have also been recorded from these horizons (selli, 1963). more than 2000 slabs with rich and well preserved plant remains from casera auernig, casera cordin grande, cason di lanza, creta di lanza, forca di pizzul, fontanone, la scaletta, mt. auernig, mt. carnizza, mt. cocco, mt. corona, mt. pic chiadin, mt. pizzul, passo pramollo, passo volaia, pian di lanza, pontebba, rio bombaso, rio bruca, rio dai amplis, rio degli uccelli (vogelbach) and sella barizze (fig. 11), are currently stored at the museo friulano di sto­ ria naturale of udine (fig. 12; courtesy of udine museum), at the university of innsbruck (austria) and at the landes­ museum klagenfurt (germany). the floras of the austrian side of the border have been mostly studied since the 1980’s. grouping the floras stratigra­ phically (fig. 13), the following information can be given (for more details see fritz & krainer, 2006, 2007). the bom­ baso formation crops out near passo pramollo (fritz & krainer, 1995, 2006), tomritsch (layers 1, 2, 5, 6) and rudniggraben (krainer in venturini, 1990b; fritz & krainer, 2006). according to the authors, typical ele­ ments of the floras include linopteris neuropteroides, neuropteris cordata, n. scheuchzeri and n. ovata. tomritsch 6 has been attributed to the odontopteris cantabrica­zone, due to the presence of sphenophyllum oblongifolium and neuropteris scheuchzeri (moved to macroneuropteris) following the mega­ flora­zonation of wagner (1984). this translates to a can­ tabrian age (late pennsylvanian; fritz & krainer, 1995). the fossiliferous horizons of malga (alm) straniger, wai­ degger alm, zollner see, passo del cason di lanza and tom­ ritsch 3 belong to the meledis formation. tomritsch 3 has been attributed, due to the presence of sphenophyllum angusfigure 8: location of the permian-carboniferous carnic basins of the carnic alps (from venturini, 1990b). pcp: permo-carboniferous sequence; vg: val gardena sandstone. 1 and 2 are idealized and very schematic sections respectively, outside and inside the permo-carboniferous basin areas. figure 9: a general stratigraphic scheme of the car boniferous-permian units in the carnic alps (from ven turini, 1990 b). the auer nig group is now called the pramollo group. ronchi et al.: pennsylvanian floras from italy: an overview of the main sites and historical collections geologia croatica 307 tifolium and pseudomariopteris busquetii, to the sphenophyllum angustifolium­ zone, which according to wagner (1984), corresponds to a lower to middle stephanian c age. one of the most prominent elements of this flora is linopteris neuropteroides var. major, as well as a high abundance in frag­ ments of the neuropteris cordata and n. ovata (fritz, 1990; fritz & krainer, 2006). vai et al. (1980) attributed the formation to the cantabrian (late moscovian to early kasimo­ vian, early stephanian) (see also pittau et al., 2008a). the floras of the pizzul formation, (rio tratte/gar­ nitzenberg (malga auernig), watschinger alm, rudniggsat­ tel, ringmauer; austria, fritz & krainer, 2006), are characterized by the occurrence of sigillaria brardii, sphenophyllum angustifolium, sph. oblonguifolium, pecopteris figure 10: stratigraphic sections from the upper part of the corona formation (a3) and the basal auernig formation (a4). section a is from the western side and section b from the southern side of the monte corona (from krai ner in venturini, 1990b, mod.). geologia croatica 65/3geologia croatica 308 feminaeformis, callipteris gigas, pseudomariopteris busquetii and poa-cordaites linearis which attributes the flora to the sphenophyllum angustifolium­zone (lower to middle stephanian c; fritz & krainer, 1994). the most important and fossiliferous formation of the pramollo group is the corona formation (ofenalm, kronalpe/ monte corona, garnitzenalm/malga carnizza, garnitz en sat­ tel, gugga, madritschenkopf, schlanitzer almweg, treßdorfer alm, naßfelder sattel/passo pramollo; fritz & kra iner, 2007). the most famous locality is monte corona (e.g., stache, 1874; frech, 1894; geyer, 1897; fritz, 1980, 1990; fritz, et al. 1990; krainer, 1992; fritz & krainer, 1993). the presence of pseudomariopteris busquetii attributes these floras to the sphenophyllum angustifolium­ zone, (lower to middle stephanian c; fritz & kra iner, 1993). linopteris neuropteroides and neuropteris cordata seem to disappear in the upper part of the formation. the appearance of the genus lebachia, an important conifer genus during the permian, is of particular interest, and not described from any of the other carboniferous floras of the carnian alps (fritz & krainer, 1993, 2006). the last formations yielding car­ boniferous floras in the carnian alps are the auernig forma­ tion, (gugga, garnitzenberg/monte carnizza, schulter and rattendorfer alm) and the carnizza formation (krainer in venturini 1990 b, pag. 96–98). the cordaites are miss­ ing in the auernig formation, while the autunian marker callipteris conferta (i.e now autunia conferta) appears (fritz & boersma, 1983; fritz & krainer, 2007). so far, there has been only one study of the palynoflora of this area (francavilla, 1966). according to the au­ thor, the microflora is characterized by the spores densosporites, dictyotriletes, lycospora and verrucosisporites. very interesting regional correlations and comparison between the italian/austrian carboniferous and permian flo­ ras could be also done in the future with neighboring countries such as slovenia (kolar­jurkovšek & jurkovšek, 2012). 3. tuscany pisani mountains the pisani mountains are located along the so­called mid­ dle­tuscan ridge, a regional morpho­structural high extend­ ing from the apuan alps to the leoni mountain (fig. 14). the stratigraphic sections of the pisani mountains, near san lorenzo of vaccoli in north­western tuscany (valle del guappero), can be subdivided into two main sedimentary cy­ cles (rau & tongiorgi, 1974). the first is represented by the alluvial to lacustrine san lorenzo schists (fig. 15), very rich in megafloras of pennsylvanian to cisuralian age. the overlying fluvial asciano red breccias and conglomerates, are attributed to the early permian for regional correlations. figure 11: detailed location of the main fossil flora sites in the italian and austrian sides of the carnic alps (from venturini, 1990b, mod.). ronchi et al.: pennsylvanian floras from italy: an overview of the main sites and historical collections geologia croatica 309 figure 12: some examples of the pennsylvanian megaflora of the carnic alps (with kind permission of udine museum). a. annularia carinata; b. pecopteris sp.; c. lilpopia raciborskii; d. paripteris cf. linguaefolia; e., f. acitheca polymorpha, g. alethopteris sp.; h. lepidodendron cf. subdichotum (determinations s. opluštil). specimens a, b, e, f and h from mt. corona (pontebba, udine); c from casera cordin grande (paularo, udine); d and g from casera auernig (near the old landslide, ponteb ba; udine). large collections from the graphite­rich metapelites and metasandstones of the san lorenzo schists were put together by sigismondo de bosniaki (1837–1921) and carlo de stefani (1851–1924), at the end of 19th century (de bosniaki, 1894; de stefani, 1901). the collection of plant fossils of de stefani (~ 1.000 specimens), is stored at the natural history museum of florence, and at the mu­ seum of natural history of pisa university (see cioppi in monechi & rook, 2010 for details; fig. 16); the palae­ ontological collection (7000 specimens of plants and ani­ mals) of de bosniaki (1894) is stored at the museum of natural history of pisa university. additional discoveries in the same area (valentona, monte togi, monte vignale, sasso campanaro) enriched the collection of those two museums. geologia croatica 65/3geologia croatica 310 figure 13: stratigraphic sections from the bombaso formation (pramollo mb.: tomritsch a) and basal pramollo group (auernig group auct) units (meledis formation or a1 formation: tomrisch b). in the inset, a location map of the two sections tomritsch a and b.) (from krainer in venturini, 1990b, mod.). a recent reorganisation of de stefani’s collection shows a flora composed of lycopsids (sigillaria, lepidodendron), horsetails (calamites, asterophyllites, annularia, sphenophyllum), ferns (acitheca, cyathocarpus, diplazites, sphenopteris), seed ferns (alethopteris, callipteris), “cy­ cads”, cordaites and conifers (walchia; landi degli in­ nocenti et al., 2008; cioppi in monechi & rook, 2010). no further information exists on the collection of de bosniaki. de bosniaki (1894) attributed the floras to the permian, while de stefani (1984) attributed them to ronchi et al.: pennsylvanian floras from italy: an overview of the main sites and historical collections geologia croatica 311 the carboniferous. fig. 17 shows a biostratigraphic and lithostratigraphic subdivision of the pennsylvanian­autunian succession, on the basis of different fossil floras found at various localities in the valle del guappero (from tre­ visan, 1955 and rau & tongiorgi, 1974 in landi degli innocenti et al., 2008; mod.). it is suggested that these floras are similar to the sardi nian flora of the san giorgio basin described by cocozza (1967). the genera annularia, asterophyllites, calamites, callipteridium, cordaites, pecopteris, and walchia, occur in both floras (landi degli innocenti et al., 2008; cioppi in monechi & rook, 2010; see fig. 18). tongiorgi unsuccessfully attempted to collect micro­palaeontological data in the area of the pisani mountains (landi degli innocenti et al., 2008). marine fossils of inferred penn­ sylvanian age, were recently discovered in the lower part of the san lorenzo schists at montuolo (pandeli et al., 2008). these discoveries indicate strong palaeoenvironmen­ tal analogies between this part of the san lorenzo schists and the coeval, coastal­neritic iano schists and sandstones figure 14: a structural sketch of the pisani mountains a. tectonic map; b. geological map (from rau & tongiorgi, 1974; tongiorgi et al., 1977). geologia croatica 65/3geologia croatica 312 cropping out near volterra (costantini et al., 1998) and the rio marina formation on elba island (pandeli et al., 2008). iano eastward, south of the arno river, in the neighbourhood of the village of iano (near volterra) (fig. 19), the basal sedi­ mentary succession of the iano schists (fig. 20) yielded, plant fossils, crinoids, bivalves and putative brachiopods of stephanian age from some of the more pelitic beds (vai & francavilla, 1974; pandeli, 1998). the plants belong to the lycopsids (stigmaria), horse­ tails (calamites, annularia,) and ferns (acitheca, aspidiopsis, cyathocarpus, diplazites; cioppi in monechi & rook, 2010) 4. sardinia trans­tensional tectonics, which deeply affected the disman­ tling of the variscan orogen, led to the opening of a number of intramontane basins, filled with lacustrine to alluvial sedi­ ments (ronchi et al., 2008 and ref. therein; see fig. 21). south-western sardinia clear evidence of the first post­orogenic clastic deposition on the island is represented by the reduced san giorgio ba­ sin sequence, which crops out in the iglesiente subregion (figs. 21 and 22), and has been studied in detail (cocozza, 1967; barca & costamagna, 2003; see fig. 23). the san giorgio flora comprises for example pecopteris arborescens, callipteridium pteridium, neuropteris planchardi and diksonites plueckenetii f. sterzeli. this flora is stored in the carbonia museum and in the museo di geologia e pale­ ontlogia “d. lovisato” of the dipartimento di scienze chi­ miche e geologiche of cagliari. cocozza (1967) pro­ posed a late stephanian age for it, based on the composition of the megafossils. the finer sediments of this basin yield­ ing a rich microflora have been attributed a late westphalian and early stephanian (a and b) age (del rio & pittau in cassinis et al., 2000; pittau & del rio, 2002b). the flora shows several endemic species, suggesting onset of a regional characterized sardinian flora resulting from the isolation of sardinia from southern europe during the penn­ sylvanian, (for more details see pittau et al., 2008b). central-eastern sardinia in central­eastern sardinia (fig. 21), there are two basins with transitional “stephano­autunian” macrofloras: the lake mulargia (sarcidano subregion), and the seui­seulo/mon­ tarbu (barbagia di seulo subregion; ronchi et al. 2008; cassinis et al., 2003). the flora of lake mulargia, with taxa such as callipteris conferta (now autunia conferta), c. naumanni, lebachia cf. hypnoides was originally dubiously ascribed to the late autunian (francavilla et al., 1977). in the seui basin and the adjacent seulo basin, outcrops with plant megafossils occur in the fine­grained sediments (cassinis et al., 2003). about 50 different species were described by lamarmora (1857), meneghini (1857), pampaloni (1900) and arcangeli (1901) for more details see comaschi caria (1959). the flora has been attributed to the pennsylvanian­cisuralian period. also a re­ cently collected flora with annularia sphenophylloides, cf. pecopteris arborcens, (?p. cyathea, pecopteris sp., pecopteris sp. aff. hemitelioides, p. unita, cordaites sp., sigillaria brardi, and artisia sp. has been ascribed to an interval span­ ning the latest carboniferous to basal early permian (autu­ nian; broutin et al., 2000; cassinis et al., 2003). figure 15: lithotratigraphic column of the palaeozoic–carnian succession of the pisani mountains, (after rau & tongiorgi, 1974). ronchi et al.: pennsylvanian floras from italy: an overview of the main sites and historical collections geologia croatica 313 figure 16: a. acitheca isomorpha (sample igf 13164); b. crossotheca pinnatifida (sample igf 332p); c. sphenophyllum oblongifolium (sample igf 160p); d. asterophyllites equiseformis (sample igf 13142); e. crossotheca pinnatifida (sample igf 424p). with the kind permission of elisabetta cioppi (museo di storia naturale dell’università degli studi di firenze, sezione di geologia e paleontologia). geologia croatica 65/3geologia croatica 314 a succession with a clear “early autunian” age (i.e., basal asselian) macro­ and microflora, is that of guardia pisano (sulcis subregion, pittau et al., 2002a), whereas succession with “late atunian” macro­ and microfloristic associations include those of escalaplano, perdasdefogu (gerrei and ogliastra subregions) and lu caparoni (nurra subregion). for more information on such basins see also ronchi et al. (1998) and cassinis et al. (2000). a com­ parative and chronostratigraphic correlation chart of the different pennsylvanian, permo­carboniferous and per­ mian basins of sardinia was produced by ronchi et al. (2008; see fig. 25). slightly different age­attributions for the latest carbo­ niferous­autunian basins are suggested by pittau et al. (2008b; fig. 26) based on the microfloristic data. given the microfloral composition, these authors distinguish four dif­ ferent palynological phases: pteridophytic pre­ striatiti pol­ len phase (westphalian c­stephanian a); florinites phase (stephanian/autunian) with relatively dominant cordaites pollen grains; potonieisporites phase (asselian) with domi­ nant monosaccate pollen (potonieisporites); vittatina-stri­ atiti pollen phase (asselian­(?)sakmarian age). the flora of central­eastern sardinia is stored at the lovisato museum at the dipartimento di scienze chimiche e geologiche of cagliari and at the natural history museum of florence (pampaloni collection). figure 17: chronological ordering of the main fossil sites of the san lorenzo schists formation according to trevisan (1955) and rau & tongiorgi (1974). trevisan (1955) indicated the index fossils for each fossil locality (from landi degli innocenti et al., 2008, mod.). figure 18: fossil floras from the pisani mountains. a. main taxonomic groups of the de stefani collection b. percentages of the taxono mical groups of the fossil sites identified in the de stefani collection. va: valentona; m. to: monte togi; tr: traina; m. vi: monte vignale; m. vi*: monte vignale (collected by fucini); sc: sasso campanaro (after landi degli innocenti et al., 2008, mod.). ronchi et al.: pennsylvanian floras from italy: an overview of the main sites and historical collections geologia croatica 315 according to broutin (in ronchi et al., 2008), the montarbu flora (barbagia di seulo subregion), firstly sig­ nalled by spano (1976), is a hygrophyllous stephanian­like assemblage, with the very fragmentary cf. rhachiphyllum sp. looking as an “autunian” callipterid. thus, the age of the montarbu flora is still not well constrained. from a palynological point of view, the montarbu mi­ croflora is framed in the potonieisporites phase (pittau et al., 2008b), being represented by high numbers of potonie isporites and florinites and with a minor component rep­ resented by plicatipollenites, costapollenites and vittatina pollen types. thus, voltziales, cordaitales and, to a lesser extent, peltaspermales appear to characterize the flora grow­ ing on dry or drained areas and slopes, in the surroundings of the lacustrine basin of montarbu, at seui and seulo, whereas a hygrophillous flora of licophytes, sphenophytes and pterophytes, covered shorelake, banks, ponds and the alluvial plain. 5. liguria in western liguria (briançonnais units) the late palaeozoic volcano­sedimentary sequence begins with fine to coarse­ grained arkosic and quartzitic meta­sediments of continental origin, formed by reworking of the underlying orthogneissic namurian(?) basement, some hundred metres thick (lisio formation). this is followed by widespread calc­alkaline rhyolitic–rhyodacitic ignimbrites (case lisetto metarhyo­ lites) (vanossi et al., 1986; cortesogno et al., 1988b), in turn covered by fluvial­lacustrine meta­conglomerates (ollano formation). this sequence of sedimentary units was generally as­ cribed to the late westphalian–stephanian interval on the basis of old records of plant remains, among which were senftenbergia (pecopteris) elegans, pecopteris nodosa, annularia longifolia (pian del fo, viozene; portis, 1887) and odontopteris obtusa (pietratagliata; squinabol, 1887). in the second half of the 20th century, bloch (1966) dis­ tinguished the following forms in the ollano formation: pecopteris plumosa dentata, sphenopteris schatzlarensis, imparipteris (neuropteris) oblique and lepidophyllum sp., together with traces of neuropteris and calamites, and at­ tributed the pertaining deposits to the late westphalian (­stephanian). according to the authors (e.g. vanossi et al., 1986), during the pennsylvanian (stephanian–?autunian), lacu­ strine shales and siltstones (murialdo formation) or conti­ nental arenites (viola and gorra schists) were deposited figure 19: generalized geological map of iano (after costantini et al., 1998 and pandeli, 1998). figure 20: lithotratigraphic column of the carboniferous-carnian succession of the iano inlier (after costantini et al., 1998). geologia croatica 65/3geologia croatica 316 figure 21: location of the main pennsylvanian and permo-carboniferous basins in sardinia: 1) san giorgio (iglesiente subregion); 2) tuppa niedda (arburese subregion); 3) lake mulargia (sarcidano subregion); 4) seui-seulo (barbagia di seulo subregion); 5) montarbu (barbagia di seulo) (from ronchi et al., 2008, mod.). either on the ollano formation, or directly on the basement. this sedimentation is associated with the emplacement of andesite, and rare dacite lavas, and volcanic breccias, mainly in lacustrine basins. tuffs and epiclastites of intermediate composition are widespread, also within continental arenites (eze formation). elsewhere in the penninic domain, pennsylvanian mag­ matism is poorly represented, whereas the continental de­ posits, associated with strike­slip tectonics, are well develo­ ped, such as within the coeval sediments of the ‘zone houiller briançonnais’ (e.g. fabre, 1961; brousmiche­del­ cambre et al., 1995 and ref. therein). ronchi et al.: pennsylvanian floras from italy: an overview of the main sites and historical collections geologia croatica 317 figure 23: stratigraphic section of the pennsylvanian san giorgio basin (from barca & costamagna, 2003). figure 22: location and schematic stratigraphic section of the san giorgio basin, close to iglesias town, in the iglesiente subregion (from del rio & pittau, 2000). in contrast with such accepted age­determinations, and with all the former stratigraphic interpretations (see e.g., vanossi et al., 1986), the pennsylvanian volcanic and sedi mentary clas­ tic deposits, which unconformably overlie a namurian crystal­ line basement, have recently been related to permian ages (dallagiovanna et al., 2009). new radioisotopic dates on the case lisetto rhyolites (285.6 ±2.6 ma concordant age), ascribed these volcanic rocks to the late sakmarian–?artinskian time­span. therefore the ollano formation should be placed in the early permian, in firm conflict with its palaeontological con­ tent, as reported in earlier literature. shiny graphite­like features, found whitin carbonife­ rous schists by de stefani (1887a) on his excursions to pietratagliata (genoa), are stored in the natural history museum of florence (cioppi in monechi & rook, 2010). 6. conclusions the italian pennsylvanian continental successions are scat­ tered across the country in the following places: 1) in the western southern alps (lombardy/switzer­ land) sparse sections occur pitched in tectonic slices at the front of the metamorphic basement. the rich macroflora from the alpe logone has been dated to the bolsovian (west­ phalian c), or duckmantian­bolsovian (westphalian b–c transition). between the maggiore and lugano lakes, the outcrops are less rich in plant remains, and perhaps slightly older than these of logone. 2) in the eastern southern alps (carnic alps) the car­ boniferous successions crop out in several localities near the border with austria, such as passo pramollo, cason di lanza, geologia croatica 65/3geologia croatica 318 figure 24: plant fossils from the pennsylvanian san giorgio basin (sw sardinia). a. calamites sp.; b. sphenophyite strobili (cf. cala mostachys); c. annularia sp.; d. neuropteris planchardii; e. odontopteris sp., f. dicksonites plueckenetii; g. cordaites cf. lingulatus. rio dai amplis, fontanone, cima val di puartis, monte piz­ zul and monte corona. although the flora has been studied partly on the austrian side, the italian outcrops are poorly studied. plant fossils occur there in several formations of the pramollo group, but are especially abundant in the corona formation. the floras seem to have ages varying from can­ tabrian up to lower to middle stephanian. 3) in tuscany, the floras mostly come from the pisani mountains and the surroundings of iano. the san lorenzo schists, from which the specimens of the historic collections were collected, have been attributed to a pennsylvanian to cisuralian age. 4) several small basins in sardinia yield megafossils and/or palynomorphs respectively of westphalian­stepha­ ronchi et al.: pennsylvanian floras from italy: an overview of the main sites and historical collections geologia croatica 319 figure 26: correlation hypothesis for lithostratigraphic units and palynological phases proposed for the continental succession of the upper carboniferous and lower permian of sardinia (from pittau et al., 2008b). figure 25: correlation chart of the main pennsylvanian and permo-carboniferous basin of sardinia (from ronchi et al., 2008, mod.). the numbers below stage names represent the duration of the stages. nian, stephano­autunian or autunian age, suggesting the differentiated onset of basins in late palaeozoic times in re­ lation to the hercynian and moreover post­hercynian tec­ tonic events. 5) the floras of liguria mostly come from pietratagliata (genoa). this flora has a late westphalian–stephanian age. acknowledgement the authors thank luca simonetto, giuseppe muscio (museo friulano di storia naturale of udine), elisabetta cioppi (museo di storia naturale dell’università degli studi di firenze, sezione di geologia e paleontologia), pao lo arduini, alessandro garassino, giorgio teruzzi (museo civico di storia naturale di milano) and attilio selva (museo etnografico e naturalistico val sanagra) for their help with the collections and obtaining information. the igcp 575 group is also acknowledged for fruitful discussion and in particular christopher j. cleal (cardiff museum), stanislav opluštil (charles university, prague) and josef pšenička (west bohemian museum in pilsen). the latter authors provided pictures and plant determinations of the val sanagra flora (from venzo collection hosted in milano mu­ seum) and of the carnic alps floras. thanks also to the museo friulano di storia naturale of udine, museo di storia natu­ rale dell’università degli studi di firenze, lovisato museum at the dipartimento di scienze chimiche e geologiche of cagliari, for kindly providing some pictures of their plant fos­ sils. giuseppe cassins (pavia university) is warmly ac­ knowledged for his many inputs to revise the topic and for an early check of this paper. we due thanks also to renato gianotti (pavia university) for sharing his knowledge on the carboniferons outcrops of nw italy. the authors thankfully acknowledge w. dimichele (nmnh smithsonian institution, washington) and an anon­ ymous reviewer for providing a constructive critical review. two authors (a.r. and g.s) were supported by the prin 2008 funds (g. oggiano coordinator). geologia croatica 65/3geologia croatica 320 references arcangeli, g. (1901): contribuzione allo studio dei vegetali permo­ carboniferi della sardegna.– paleont. it., 7, 91–120. arthaud, f. & matte, p. (1977): late paleozoic strike­slip faulting in southern europe and northern africa: result of a right­lateral shear zone between the appalachians and the urals.– gsa bull., 88, 1305–1320. doi: 10.1130/0016­7606(1977)88 barca, s. & costamagna l. g. (2003): the upper carboniferous s. giorgio succession (iglesiente, sw sardinia): stratigraphy, de­ positional setting and evolution of a late to post­variscan molassic basin.– boll. soc. geol. it., volume speciale, 2 (2003), 89–98. barca, s., costamagna, l.g. & del rio, m. (1995b): affiora­ menti permo­carboniferi e mesotriassici fra porto piscinas e punta acqua durci (arburese, sardegna sw).– boll. soc. sarda sci. nat., sassari, 30, 1–11. baggio, p. & de marco, l. (1960): la serie basale tardo­paleozoi­ ca del varesotto e le mineralizzazioni ad uranio della valganna. stu­ di e ricerche della divisione geomineraria, comitato nazionale energia nucleare, iii, 15–103. baucon, a. & neto de carvalho, c. (2008): from the river to the sea: pramollo, a new ichnolagerstätte from the carnic alps (car­ boniferous, italy–austria).– studi trent. sci. nat. acta geol., 83, 87–114. bernoulli, d. (1964): zur geologie des monte generoso (lombar­ dische alpen). ein beitrag zur kenntnis der südalpinen sedimente. beiträge zur geologischen karte der schweiz, neue folge 118 lie­ ferung, 134 p. bertotti, g. (1991): early mesozoic extension and alpine shorten­ ing in the western southern alps: the geology of the area between lugano and menaggio (lombardy, northern italy).– mem. sci. ge­ ol., padova, con 1 carta geologica, 43, 17–123. bloch, j.p. (1966): le permien du domaine briançonnais ligure. essai de cronologie des formations ante triasiques. atti del symposium sul verrucano, pisa.– atti soc. toscana di scienze naturali, special issue, 99–115. brousmiche­delcambre, c., mercier, d. & coquel, r. (1995) : implications stratigraphiques de la révision de la flore carbonifère au sud de brianc¸on.– c. r. acad. sci., se´rie ii, 320, 335–340. casati, p. (1978): tettonismo e sedimentazione nel settore occidenta­ le delle alpi meridionali durante il tardo paleozoico, il triassico e il giurassico.– riv. it. pal. strat., 84, 313–326. cassinis, g., avanzini, m., cortesogno, l., dallagiovan­ na, g., di stefano, p., gaggero, l., gullo, m., massa­ ri, f., neri, c., ronchi, a., seno, s., vanossi, m., sven­ turini, c. (1998): synthetic upper palaeozoic correlation charts of selected italian areas.– atti ticinensi di scienze della terra, 40, 65–120. cassinis, g., perotti, c. & venturini, c. (1997): examples of late hercynian transtensional tectonics in the southern alps (italy).– in: dickins, j.m., yang, z., yin, h., lucas, s.g. & an­ charyya, s.k. (eds.): late palaeozoic and early mesozoic cir­ cum­pacific events and their global correlation. cambridge university press, cambridge, 41–50. cassinis, g., cortesogno, l., gaggero, l., pittau, p., ron­ chi, a. & sarria, e. (coordinators) (2000): late palaeozoic con­ tinental basins of sardinia.– field trip guidebook, 15–18 september, 1999. inter. field conference on “the continental permian of the southern alps and sardinia (italy). regional reports and general correlations”, 15–25 sept. 1999, brescia, p. 116. cassinis, g., cortesogno, l., gaggero, l., ronchi, a., sarria, e., serri, r. & calzia, p. (2003): reconstruction of igneous, tectonic and sedimentary events in the latest carbonifer­ ous–early permian seui basin (sardinia, italy).– in: decandia, f.a., cassinis, g. & spina, a. (eds): spec. proc. int. meeting “late palaeozoic to early mesozoic events of mediterranean eu­ rope, and additional regional reports”, siena, 2001. boll. soc. geol. it., vol. spec., 2, 99–117. cassinis, g. & perotti, c.r. (2007): a stratigraphic and tectonic review of the italian southern alpine permian.– palaeoworld, 16/1–3, 140–173. doi: 10.1016/j.palwor.2007.05.004 cassinis, g. & ronchi, a. (2002): the (late­) post­variscan conti­ nental succession of sardinia.– rend. soc. pal. ital., 1, 77–92. cocozza, t. (1967): il permo­carbonifero del bacino di san giorgio (iglesiente, sardegna sud­occidentale).– mem. soc. geol. it., 6, 6–642. comaschi caria, i. (1959): le piante fossili della sardegna. mem. riv. it. pal. strat., 7, 1–176. cortesogno, l., dallagiovanna, g. & vanossi, m. (1988a): paléogéographie du briançonnais ligure d’après les lithoclastes des formations permo­carbonifères.– géologie alp., mém. h.s., 14, 9–28. cortesogno, l., dallagiovanna, g., vannucci, r. & va­ nossi, m. (1988b): volcanisme, sédimentation et tectonique pen­ dant le permo­carbonifère en briançonnais ligure: une revue. eclogae geol. helv., 81, 487–510. costantini, a., elter, f.m., pandeli, e. & sandrelli, f. (1998) : geologia dell’ area di iano (toscana meridionale, italia).– boll. soc. geol. it., 117, 187–218. dallagiovanna, g., gaggero, l., maino, m., seno, s. & tiepolo, m. (2009) : u–pb zircon ages for post­variscan volca­ nism in the ligurian alps (northern italy).– j. geol. soc. lond., 166, 101–114. doi: 10.1144/0016­76492008­027 de stefani, c. (1901): flore carbonifere e permiane della toscana.– pubbl. reg. ist. studi sup. pratici e perfez., tipografia g. carne­ secchi e figli, firenze, 212 p. del rio, m. (1973): palinologia di un vello “permo­carbonifero” del bacino di san giorgio (sardegna sud­occidentale).– boll. soc. geol. it., 93, 485–494. del rio, m. & pittau, p. (2000): the upper carboniferous of the san giorgio basin (iglesiente).– in: cassinis, g., corteso­ gno, l., gaggero, l., pittau, p., ronchi, a. & sarria, e. (eds.): late paleozoic continental basins of sardinia. field trip guidebook, 15–18 september, 1999. field conference on: “the continental permian of the southern alps and sardinia (italy). re­ gional reports and general correlations”. escher, b.g. (1911): über die prätriasische faltung in den west­alpen. diss, zürich. francavilla, f. (1966): spore nel flysch hochwipfel.– giornale di geologia, 2, 493–526. frech, f. (1894): die karnischen alpen. ein beitrag zur vergleichen­ den gebirgstektonik.– halle (max niemeyer), 514 p. fritz, a. (1980): fundberichte über pflanzenfossilien aus kämten 1980.– carinthia ii, 170(90), 221–238. fritz, a. & boersma, m. (1983): fundberichte über pflanzenfossi­ lien aus kämten.– carinthia ii, 173(93), 19–41. fritz, a. & boersma, m. (1987): fundberichte über pflanzenfossi­ lien aus kämten 1987 – beitrag 15: wunderstätten (unterperm), st. pauler berge.– carinthia ii, 177(97), jahrgang, 381–394. fritz, a., boersma, m. & krainer, k. (1987): steinkohlenzeit­ liche pflanzenfossilien aus kämten.– 49. sonderheft des naturwis­ senschaftlichen verreins für kämten, klagenfurt, 89 p. fritz, a., boersma, m. & krainer, k. (1990): carinthia ii, sonderheft, 4, 120. fritz, a. & krainer, k. (1994): die megflora “garnitzenberg­süd­ os alpha” aus der auernig­schichtgruppe der karnischen alpen.– carinthia ii, 441–465. ronchi et al.: pennsylvanian floras from italy: an overview of the main sites and historical collections geologia croatica 321 fritz, a. & krainer, k. (1995): die megaflora tomritsch­3 und tomritsch­6 aus den oberkarbonen auernigschichten der karni­ schen alpen.– carinthia ii, 553–583. fritz, a. & krainer, k. (2004): pflanzenfossilien aus den grenz­ landbänken der rattendorfer alm (kernten, karnische alpen).– ca­ rinthia ii, 194(114), jahrgang, 445–454. fritz, a. & krainer, k. (2006): vegetationsgeschichtliche und flo­ rengeographische untersuchungen im oberkarbon und unterperm der ost­ und südalpen (teil 1).– carinthia ii, 196(116), 93–120. fritz, a. & krainer, k. (2007): vegetationsgeschichtliche und flo­ rengeographische untersuchungen im oberkarbon und unterperm der ost­ und südalpen (teil 2).– carinthia ii, 197(117), 91–148. fritz, a. & krainer, k. (1993): eine neue megaflora aus dem ste­ fan der kronalpe.– carinthia ii, 485–517. fritz, a. & ucik, f.h. (2003): neufunde von pflanzenfossilien aus kämten.– carinthia ii, 193(113), 449–454. gaetani, m., gianotti, r., jadoul, f., ciarapica, g., ciril­ li, s., lualdi, a., passeri, l., pellegrini, m. & tanno­ ia, g. (1986): carbonifero superiore, permiano e triassico nell’area lariana.– mem. soc. geol. it., 32, 5–48. geyer, g. (1897): über dei geologsichen verhältnisse im pontafeler abschnitte der karnischen alpen.– jahrbuch der k.k. geol. r.a., p. 46. graeter, p. (1951): geologie und petrographie des malcantone (süd­ liches tessin).– schweiz. mineral. petrogr. mitt., 31/2, 361–483. heer, o. (1876): flora fossilis helvetiae, 47. verlag von j. wurster and co., zurich, 41–42. jongmans, w.j. (1950): mitteilungen zur karbonflora der schweiz. i.– eclogae geol. helv., 43/2, 95–104. jongmans, w.j. (1960): die karbonflora der schweiz. beiträge zur geologiche karte der schweiz (nf), 108, 1–97. kolar­jurkovšek, t. & jurkovšek, b. (2012): late carbonerous floras in slovenia – a review, 65/3, 323–328. doi: 104154/gc.2012.21 krainer, k. (1990): the fossil flora of the auering group.– field workshop on carboniferous to permian sequence of the pramollo­ nassfeld basin, 110–113. lamarmora, a. (1857): voyage en sardaigne: troisième partie. des­ cription géologique et paléontologique. torino, bocca impr. royale, 2, 707–781. landi degl’innocenti, v., pandeli, e., mariotti lippi, m. & cioppi, e. (2008): the carboniferous­permian succession of the pisani mountains (tuscany, italy): preliminary data from the de stefani collection (natural history museum of florence).– boll. soc. geol. it. (ital. j. geosci.), 127/3, 545–558. lehner, p. (1952): zur geologie des gebietes der denti della vecchia, des m. broglia, des m. brè, und des m. san salvatore bei lugano.– eclogae geol. helv., 45, 86–159. magnani, m., (1946): sulla presenza di terreni spettanti al carboni­ fero nei monti di menaggio (valle sanagra). atti della regia ac­ cademia delle scienze di torino 80, i, 199–206. massari, f., pesavento, m. & venturini, c. (1991): the per­ mian carboniferons cyclothenis of the pramollo basin sequence (carnic alps).– in: venturini, c. (ed.): field workshop on car­ boniferous to permian sequence of the pramollo­nassfeld basin (carnic alps), guidebook, 171–185. meneghini, g. (1857) : paléontologie de l’île de sardaigne.– in: lamarmora, a. (ed.): voyage en sardaigne, iv, paris. monechi, s. & rook, l. (2010): the museum of natural history of the university of florence. the geological and paleontological collections isbn 978­88­6453­189­2 (print) © 2010 firenze uni­ versity press. opluštil, s. & cleal, c.j. (2007): a comparative analysis of some late carboniferous basins of variscan europe.– geol. mag., 144, 417–448. doi: 10.1017/s0016756807003330 pampaloni, l. (1900): i terreni carboniferi di seui ed oolitici di per­ daliana.– red. acc. lincei., cl. sc. sif. math. e nat., 9/2, 345–349. pandeli, e. (1998): permo­triassic siliciclastic sedimentation in the northern apennines: new data from the iano metamorphic inlier (florence).– mem. soc. geol. it., 53, 185–206. pandeli, e. (2002): sedimentary­tectonic evolution of the tuscan ar­ ea (northern apennines, italy) fro late “autunian” to carnian.– boll. soc. geol. it., vol. spec., 1, 251–262. pandeli, e., dominici, s., landi degl’innocenti, v., ciop­ pi, e. & tangocci, f. (2008): marine fossils in the late carbon­ iferous metasediments of the pisani mountains (tuscany, italy).– boll. soc. geol. it. (ital. j. geosci.), 127/3, 559–565. pittau, p. & del rio, m. (2002): palynofloral biostratigraphy of the permian and triassic sequences of sardinia.– rend. soc. pal. it., 1, 93–109. pittau, p., barca, s., cocherie, a., del rio, m., fanning, m. & rossi, p. (2002): le bassin permien de guardia pisano (sud­ ouest de la sardaigne, italie): palynostratigraphie, paléo phyto géo­ gra phie, corrélations et âge radiométrique des produits volcani­ ques as sociés. geobios, 35, 561–580. doi: 10.1016/s00166995(02) 00069­4 pittau, p., del rio, m., cotza, f., ronchi, a., santi, g., & gianotti, r. (2008a): pennsylvanian miospore assemblages from the bèdero section, varese, italian southern alps.– revue de mi­ cropaléontologie, 51, 133–166 doi: 10.1016/j.revmic.2007.11.001. pittau, p., del rio, m. & funedda, a. (2008b): relationships between plant communities characterization and basin formation in the carboniferous­permian of sardinia. boll. soc. geol. it. (ital. j. geosci.), 127/3, 7–653. portis, a. (1887): sulla scoperta delle piante fossili carbonifere di vio­ zene nell’alta valle del tanaro.– boll. r. com. geol. it., 18, 417–420. rau, a. & tongiorgi, m. (1974): geologia dei monti pisani a sud­ est della valle del guappero.– mem. soc. geol. it., 13, 227–408. ronchi, a., broutin, j., diez, j­b., freytet, p., galtier, j. & lethiers, f. (1998): new palaeontological discoveries in some early permian sequences of sardinia. biostratigraphic and palaeo­ geographic implications.– c. r. acad. sci. paris, earth & planet. sci., 327, 713–719. doi:10.1016/s1251­8050(99) ronchi, a., sarria, e. & broutin, j. (2008): the “autuniano sar do”: basic features for a correlation through the western medi­ terranean and paleoeurope.– boll. soc. geol. it., 127/3, 655–681. selli, r. (1963): schema geologico delle alpi carniche e giulie occi­ dentali.– giornale di geologia, 2/30, 1–136. sordelli, f. (1896): flora fossile insubrica. studi sulla vegetazione in lombardia durante i tempi geologici.– tipografia cogliati mila­ no, 298 p. spano, c. (1976): nuovo contributo alla conoscenza delle piante del paleozoico della sardegna.– rend. seminari fac. sci. univ. caglia­ ri, 46/3–4, 385–433. squinabol, s. (1887): nota preliminare su alcune impronte fossili nel carbonifero superiore di pietratagliata. giornale della societa’ di letture e conversazioni scientifiche di genova 10/6–7. tipogra­ fia di gaetano schenone, genova. stache, g. (1874): die paläozoischen gebiete der ostalpen.– jb. der k.k. geol. r.a., 24/2. stadler, g., teichmuller, m. & teichmuller, r. (1976): zur geotermischen geschichte des karbons von manno bei lugano des “karbons” von falletti (sesia­zone der westalpen).– n. jb. geol. paleont. abh., 152, 177–198. tongiorgi m., rau, a. & martini, i.p. (1977): sedimentology of early­alpine, fluvio­marine clastic deposits (verrucano, triassic) in the monti pisani (italy).– sediment. geol., 17, 311–332. doi: 10.1016/0037­0738(77)90051­3 geologia croatica 65/3geologia croatica 322 vai, g.b. & francavilla, f. (1974): nuovo rinvenimento di piante dello stefaniano a iano (toscana).– boll. soc. geol. it., 93, 73–79. vai, g.b., francavilla, f., ferrari, a. & contarin, m.t. (1980): la sezione del monte carnizza (carbonifero superiore, alpi carniche).– mem. soc. geol. it., 20, 267–276. vai, g.b. & venturini, c. (1997): moscovian and artinskian rocks in the frame of the cyclic permo­carboniferous deposits of the car­ nic alps and related areas.– geodiversitas, 19, 173–186. van amerom, h.w.j. & kabon, h. (2000): neue fossile floren aus dem nötscher karbon (2. teil).– carinthia ii, 190(110), 483–516. van amerom, h.w.j. & schönlaub, h.p. (1992): pflanzenfossili­ en aus dem karbon von nötsch und der hochwipfel­formation der karnischen alpen (österreich).– jb. geol. b.­a., 135/1, 195–216. van amerom, h.w.j., boersma, m. & riehl­herwirsch, g. (1976a): zum alter des “karbons von christophberg”, kämten, östeich.– geologie en mijnbouw, 55/3–4, 211–212. van amerom, h.w.j., boersma, m., niedermayr, g. & scheriau­niedermayr, e. (1976b): das permische alter der “kar bon”­flora von kötschach (kärnten, österreich).– carinthia ii 166 (86), 93–101. vanossi, m., cortesogno, l., galbiati, b., messiga, b., piccardo, g.b. & vannucci, r. (1986): geologia delle alpi liguri: dati, problemi, ipotesi.– mem. soc. geol. it., 28, 5–75. venturini, c. (1983): il bacino tardo­ercinico di pramollo (alpi car­ niche): un’evoluzione regolata dalla tettonica sinsedimentaria.– mem. soc. geol. it., 24, 23–42. venturini, c. (1990a): geologia delle alpi carniche centro­orientali. pubblicazione 36, museo friulano di storia naturale, udine, 220 p. venturini, c. (1990b): field workshop on carboniferous to permian sequence of the pramollo­nassfeld basin (carnic alps), guide­ book. arti grafiche friulane, udine, 159 p. venturini, c. (1991): introduction to the geology of the pramollo ba­ sin (carnic alps) and its surroundings.– in: venturini c. (ed.): workshop proceedings on tectonics and stratigraphy of the pramol­ lo basin (carnic alps).– giorn. geologia, ser. 3a, 53/1, 13–47. venturini, c. (2002a): la sequenza permo­carbonifera.– in: aa.vv. guide geologiche regionali – alpi e prealpi carniche e giulie, friuli venezia giulia, a cura della società geologica italiana, 9, 20–31, be­ma editrice. venturini, c. (2006): evoluzione geologica delle alpi carniche. pub­ blicazione 48, edizioni del museo friulano di storia naturale – co­ mune di udine, 208 p. venturini, c., pondrelli, m., delzotto, s., fontana, d. & discenza, k. (2002): carta geologica delle alpi carniche (scala 1:25.000, 930 kmq). s.e.l.c.a., firenze. venturini, c., krainer, k. & massari, f. (1991): field trips in the pramollo basin (carnic alps).– in: venturini, c. (ed.): workshop proceedings on tectonics and stratigraphy of the pramollo basin (carnic alps). giornale di geologia, ser. 3a, 53/1, 49–126. venzo, s. (1951): les gisements nouveaux du carbonifère (westpha­ lien) dans les alpes lombardes. c. r. du 31e congrès de stratigra­ phie et de géologie du carbonifère. herleen 1951, 647–649. venzo, s. & maglia, l. (1947): lembi carboniferi trasgressivi sui micascisi alla “fronte sedimentaria subalpina” del comasco (ac­ quaseria di menaggio­bocchetta di s. bernardo) e del varesotto (bèdero). atti soc. it. sci. nat., 85/86, 33–70. wagner, r.h. (1984): megaflora zones of the carboniferous.– c.r. ix. congr. int. stratigr. geol. cerbonifère, washington and cham­ paign­urbana 1979, 2, 9–134. manuscript received august 02, 2012 revised manuscript accepted september 21, 2012 available online october 30, 2012 2019 | 72 / special issue | 93–109 | 16 figs. | 4 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society article history: manuscript received april 23, 2019 revised manuscript accepted july 02, 2019 available online december 20, 2019 keywords: tethyan-south china sea, subduction, zircon u–pb age, geochemistry 1. introduction during the mesozoic era, there was an ancient sea situated in the same place as the present-day south china sea (south of hainan island), which experienced northward subduction during the late mesozoic. hainan island lies along the front edge of this ancient subduction zone, and thus was in a special position in the late mesozoic framework of southeastern china (li et al., 2000; yang et al., 1989). due to the close relationship with oceanic crust, attention was focused on the intense tectonic magmatism that took place during the late mesozoic (yun et al., 2004). there are several competing explanations for the tectonic position and formation mechanism of hainan island. for example, jia et al. (2010) & wang et al. (2012) suggested that the tunchang intrusion of hainan island is composed of adakitic rocks, and was formed by asthenospheric upwelling resulting from the recession of pacific subduction. tang et al. (2014) & wang et al. (1991) believed that the late yanshanian magmatism of hainan island occurred in a post-arc extensional environment. yun et al. (2003) considered that the formation of late mesozoic granites in hainan island was closely associated with large-scale lithospheric extension–thinning, basaltic magma underplating, and enriched mantle-derived basaltic magma related to oceanic crust subduction, which contributed heat and material to the formation and evolution of the granites. from a systematic study of cretaceous basic dykes on hainan island, ge (2003) proposed that the the characteristics of granites in the gaofeng and baocheng areas, hainan province, china: response to subduction of the tethyan south china sea yuan xiaobo1*, fang nianqiao2, zhang zhenguo4 and dong hailong3 1 hebei normal university of science and technology, institute of marine science, qinhuangdao, 066004 china; (*corresponding author: yuanxiaobo2011@163.com) 2 china university of geosciences (beiing), school of ocean sciences, beijing, 100083 china 3 nonferrous geological prospecting bureau of inner mongolia, hohhot, 016043 china 4 liaoning technical university, mining institute, fuxin, 123000 china doi: 10.4154/gc.2019.19 abstract during the early mesozoic era there was intense magmatic activity near hainan island, south china. as a result, the granites of hainan island provide information on, and are suitable material to potentially improve understanding of the cretaceous tectonic environment of the northern margin of the south china sea. the gaofeng and baocheng intrusions are composed mainly of mediumto fine-grained biotite adamellite (baocheng) and granodiorite (gaofeng). the two intrusions yielded u–pb la-icp-ms zircon ages of 107.7 ± 6.1 ma (gaofeng) and 105.8 ± 2.4 ma (baocheng). regarding the major elements, the gaofeng and baocheng intrusions had medium si and alkali contents and high ca, mg, and al contents, with an aluminum saturation index of 0.95–1.03 and 1.05–1.30. the trace element and rare earth element (ree) characteristics showed that the two intrusions have intense heavy ree/light ree (hree/lree) fractionation, lree enrichment, hree depletion, and weak negative eu anomalies. the intrusions were enriched in high field-strength elements and depleted in large ion lithophile elements. these geochemical characteristics indicate that the hainan province was in a tectonic subduction environment in the late yanshanian period. multiple geochemical characteristics demonstrate that the granites in the hainan province were formed by a different mechanism and in a different setting from those in fujian and zhejiang. the late mesozoic granites of fujian and zhejiang were formed by the western pacific subduction. however, hainan island was under an arc environment formed by the northward subduction of the tethyan-south china sea during the cretaceous leading to emplacement of the gaofeng and baocheng intrusions. dykes were formed in an intraplate extensional environment, which, together with cretaceous basic dykes in the coastal region of northern guangdong and fujian, indicated that southeastern china experienced an extensional tectonic environment during the cretaceous period. the current hypotheses for the formation of late mesozoic igneous rocks in hainan island are extensional thinning, post-arc extension, and intraplate anorogenic movement (tang, 2014; jia et al., 2010; yun et al., 2004; li et al., 2000; yang et al., 1989). however, a previous study observed that cretaceous andesites (qiang, 2016) in the hainan province and detrital zircons from the lumuwan formation in the ledong basin showed signatures of a continental-margin arc (tang, 2014). we collected samples from the gaofeng and baocheng intrusions, and performed u–pb la-icp-ms zircon dating and total-rock geochemical analysis to obtain a clear understanding of the geotectonic setting represented by the late mesozoic rocks on hainan island. 2. geologic setting and sampling location this study focused on the gaofeng and baocheng intrusions (table 1), which are represented by granitic rocks collected from the two areas. the gaofeng intrusion lies at the junction of the southern margin of the wuzhishan depression belt and the northern margin of the south china sea platform in the first-order tectonic unit (i.e., the south china fold system). the gaofeng complex is a ring-like intrusion emplaced northward within the g eo lo gi a c ro at ic a geologia croatica 72 / special issue94 lower cretaceous lumuwan formation. the baocheng intrusion occurs in baoting county in the southeastern hainan province, north of the jiusuo–lingshui structural belt, and is also a relatively obvious ring-like complex (fig. 1). previous research on the gaofeng and baocheng granites is limited, but concluded that the baocheng rocks are granodiorites and the gaofeng granites are monzogranites (fig. 2).the distribution of the two rock masses generally occurs along an east-west axis, without any figure 1. a simplified geological map of hainan island.1: early cretaceous baoting unit; 2: early cretaceous baoyue unit; 3: early cretaceous liaociling unit; 4: early cretaceous granite porphyry; 5: early cretaceous liugong unit; 6: early cretaceous fushidou unit; 7: early cretaceous jiamao unit; 8. early cretaceous shuiding unit; 9: middle triassic chaopen unit; 10: middle triassic bushancun unit; 11: middle triassic jiewei unit.; 12: middle permian tongshi unit; 13; quaternary basuo formation; 14: coastal zone; 15: deep fault zone; 16: normal fault; 17: sampling point. table 1. the sample co-ordinates of all samples processed in the study. area gaofeng sample number yl501 yl601 yl701 yl703 location 18°19'10.9''n， 109°19'51.7''e 18°21'15,9''n，109°19'36.0''e 18°20'19.6''n，109°19'41.0''e 18°20'19.0''n，109°19'39.2''e area baocheng sample number shy101 shy201 shy302 shy401 location 18°32'00.9''n，109°50'21.2''e 18°31'55.8''n，109°50'17.3''e 18°31'51.3''n，109°50'19.2''e 18°31'41.8''n，109°50'26.8''e g eologia c roatica xiaobo et al.: the characteristics of granites in the gaofeng and baocheng areas, hainan province, china ... 95 primary banded structure. the central facies of the rock mass is dominated by monzogranite, which has a fine-medium porphyroid texture. a small amount of granodiorite and granite can be observed; the marginal facies of the rock mass is dominated by granodiorite and quartz diorite, showing a medium-grained texture. from the centre to the margin, the lithological variation of the rock mass changes from monzogranite to granodiorite , quartz diorite, and the texture alters from fine-medium porphyroid to medium-grained fabric. there are intrusions in the baocheng rock mass, composed of granite porphyry or granodiorite porphyry, and the contact zone between the rock mass and the surrounding rocks gradually changes to quartz porphyry or felsite porphyry. the dyke rocks are granite, aplite, lamprophyre and quartz veins. lithologically, the cretaceous period mainly consists of sandstone, sandy conglomeratic, and mudstone. lower tertiary system formations from bottom to top include the changliu, liushagang, and weizhou formations. lacustrine deposits make up the majority of these formations. neogene formations include the xiayang formation, jiaowei formation, dengloujiao formation, and the wanglougang formation. the majority of these sediments include neritic facies where the dominant lithology is coarse-grained sandstone and mudstone rich in glauconite, and foraminifera. quaternary lithologies mainly consists of clay, tuff, pyroclastic rocks, and basalt. figure 2. a q-a-p diagram (after maniar et al., 1989). figure 3. photomicrographs of gaofeng granite textures: (3a)gaofeng (yl501) plane polarized light, and (3b)crossed polars (granitic texture, quartz shows xenomorphic granular texture, plagioclase shows perthitic texture); (3c)gaofeng (yl501) plane polarized light, and (3d)crossed polars (plagioclase show carlsbad-albite compound twin). g eo lo gi a c ro at ic a geologia croatica 72 / special issue96 3. petrography the granodiorite collected from the gaofeng intrusion in the southern hainan province has a fineto medium-grained granitic texture. in describing the main rock-forming minerals: potash feldspar is of reddish-brown colour and xenomorphic-platy in form, with crosshatched twins and ribbon texture characteristics; plagioclase is euhedral to subhedral-platy, with developed polysynthetic twins and sericitization; quartz is xenomorphic-granular in form with undulating extinction. biotite, which appears dark green to yellow, is euhedral to subhedral-flaky, with one perfect cleavage and obvious pleochroism present. accessory minerals predominantly include zircon and apatite. the main rock-forming minerals are quartz (20-30%), potash feldspar (17-20%), plagioclase (30-40%), biotite (5-7%), and hornblende (8-10%) (fig. 3). the samples from the baocheng intrusion are biotite adamellite. the rocks are light-grey in colour, massive with a mediumfine porphyritic-like texture. the main phenocrysts are potash feldspar with some quartz. of the main rock-forming minerals, plagioclase is euhedral to subhedral-platy, with a ring-like texture. most plagioclase grains occur as polysynthetic twins, and some are associated with strong sericitization. potash feldspar is brownish-gray and xenomorphic-platy, with a typical ribbon texture. quartz is anhedral granular, with undulating extinction. hornblende is mostly idiomorphic to hypidiomorphic-granular, with moderate relief, two cleavage directions and pleochroism. it is dark green-light yellow in colour, with developed biotite reaction borders. accessory minerals include apatite, zircon, and other opaque minerals. the mineral composition of the baocheng intrusions is quartz (25–30%), potash feldspar (8–40%), plagioclase (5–25%), and biotite (5–7%), with hornblende observed locally (approximately 3%) (fig. 4). 4. analytical methods the element analysis was completed at the laboratory of the hebei institute of regional geology & mineral survey. major elements were measured with a philips pw2404 x ray fluorescence spectrometer (xrf), using the alkali-fusion cast-bead method. the national standard reference material gbw07103 was used for quality monitoring during the measurement process. the nitric acid + hydrofluoric acid + perchloric acid open-vessel decomposition method was combined with nitric acid + hydrofluoric acid sealed-vessel decomposition to ensure complete dissolution of the samples. the equipment used for this assay was an element i-type plasma mass spectrometer produced by the german company finnigan-mat, as well as the national standard reference materials gbw07106 and gbw07312 for quality monitoring. the method is la-icp-ms (inductively coupled plasma mass spectrometry). representative samples yl701 and figure 4. photomicrographs of baocheng granite textures: (4a)baocheng (shy401) plane polarized light, and (4b)crossed polars (biotite surround by plagioclase phenocryst); (4c)baocheng (shy401) plane polarized light, and (4d)crossed polars (porphyritic-like texture). g eologia c roatica xiaobo et al.: the characteristics of granites in the gaofeng and baocheng areas, hainan province, china ... 97 shy401 were selected for la-icp-ms zircon u-pb dating, and the dating samples corresponded to the samples for main and trace element analysis. the whole rock fresh sample was crushed to 80-120 mesh, then the zircon content was enriched by gravity and magnetic separation methods. zircon grains were selected under binocular microscope, discharged onto the double-sided tape, placed in the mould and fixed with epoxy resin. after the zircon grains were consolidated, they were polished to expose the surface. zircon separation was performed at the lab center of the hebei institute of regional geology & mineral survey. a laser ablation-inductively coupled plasma mass spectrometry (laicp-ms) device was used for in situ zircon u–pb dating and trace element measuring at the state key laboratory of continental dynamics, northwest university. a 193 nm arf excimer laser with a spot size of 30 μm was connected to an elan61(x) drctype icp-ms and used as the carrier gas for the ablation material. the zircon standard 91500 was used as the external standard to calibrate the isotopic fractionation during zircon u–pb isotopic dating. using the usgs reference glass nist 610 as the external standard and si as the internal standard, quantitative calculations were performed to assay the zircon trace-element content. the 91500 + nist 610 standard zircon was measured once for every six sample spot measurements. specific details of the laboratory processes are provided in yuan et al. (2003). u–pb age concordia plots of zircon samples and an age-weighted average calculation were both determined with isoplot (ver. 3) (ludwig, 2003). 5. results 5.1. zircon u–pb ages eight concordant ages were obtained from the gaofeng intrusion (yl701), and nine from the baocheng intrusion (shy401). the analytical results are listed in table 2. most zircons from the two intrusions were idiomorphic to hypidiomorphic-columnar, with clean and smooth crystal surfaces. in general the crystals had a length/width ratio of 2:1, but some individual crystals were up to 3:1. cathodoluminescence images demonstrated that the zircons from both intrusions displayed clear concentric zoning, with th/u ratios of 0.36–0.93 (gaofeng) and 0.53–0.90 (baocheng). as all ratio values were larger than 0.1, these zircons were determined to be magmatic (belousova et al., 2002). the gaofeng intrusion had a weighted average age of (107.7 ± 6.1) ma, and the baocheng intrusion an age of (105.8 ± 2.4) ma, which may represent the formation ages of the two intrusions (fig. 5-6). 5.2. results 5.2.1. major elements table 3. lists the chemical compositions of the representative samples from the gaofeng and baocheng intrusions. granitic rocks from the gaofeng intrusion had a sio2 content of 65.90– 72.42%, total alkali content (k2o + na2o) of 7.29–8.13%, and k2o/na2o ratios of 1.27–1.6. on the total alkali–sio2 diagram for intrusive rocks (middlemost, 1994; fig. 7) all samples fell within the granite field, with the exception of sample yl501 that fell outside the granodiorite domain. on the sio2–k2o diagram, all samples were within the high-k calc-alkaline series domain. on the a/cnk–a/nk diagram, most of the samples were within the metaluminous rock domain (fig. 8a). the aluminum saturation index was 0.95–1.03, and the rittmann serial index(σ) ranged from 2.26 to 2.32. the magma differentiation index (di) ta bl e 2. l a -ic pm s re su lts o f t he z irc on s f ro m th e g ao fe ng a nd b ao ch en g ba th ol ith . a na ly se d sp ot s co nc en tr at io ns (μ g/ g) at om ic ra tio s a pp ar en t a ge s（ m a) 23 2 th 23 8 u 20 6 pb th /u 20 7 pb /20 6 pb 1σ 20 7 pb /23 5 u 1σ 20 6 pb /23 8 u 1σ 20 7 pb /23 5 u 1σ 20 6 pb /23 8 u 1σ yl 70 12 50 .9 5 86 .4 5 6. 03 0. 59 0. 05 10 0. 00 84 0. 11 71 0. 01 87 0. 01 66 0. 00 05 11 2. 4 17 .0 10 6. 4 3. 37 yl 70 14 10 72 .1 0 13 93 .7 0 96 .1 2 0. 77 0. 05 58 0. 00 26 0. 12 73 0. 00 48 0. 01 65 0. 00 03 12 1. 7 4. 3 10 5. 7 1. 72 yl 70 16 10 7. 78 15 3. 27 10 .2 4 0. 70 0. 04 56 0. 00 49 0. 10 09 0. 01 04 0. 01 60 0. 00 04 97 .6 9. 6 10 2. 6 2. 32 yl 70 17 11 7. 51 12 9. 00 8. 90 0. 91 0. 05 08 0. 00 57 0. 11 60 0. 01 25 0. 01 66 0. 00 04 11 1. 5 11 .4 10 6. 0 2. 59 yl 70 18 44 6. 00 61 4. 25 39 .4 8 0. 73 0. 04 59 0. 00 29 0. 09 79 0. 00 56 0. 01 55 0. 00 03 94 .9 5. 2 98 .9 1. 79 yl 70 19 17 4. 51 29 8. 16 20 .5 4 0. 59 0. 04 93 0. 00 35 0. 11 27 0. 00 73 0. 01 66 0. 00 03 10 8. 4 6. 6 10 6. 1 2. 01 yl 70 110 19 5. 72 21 1. 17 15 .6 7 0. 93 0. 05 18 0. 00 47 0. 12 78 0. 01 09 0. 01 79 0. 00 04 12 2. 1 9. 8 11 4. 4 2. 53 yl 70 113 18 5. 97 52 0. 50 40 .4 0 0. 36 0. 05 09 0. 00 23 0. 13 17 0. 00 48 0. 01 88 0. 00 03 12 5. 6 4. 3 11 9. 9 1. 91 yl 70 115 27 0. 54 33 3. 97 23 .3 3 0. 81 0. 04 75 0. 00 32 0. 11 09 0. 00 67 0. 01 69 0. 00 03 10 6. 8 6. 2 10 8. 2 2. 00 sh y4 01 -3 25 7. 50 39 7. 83 27 .5 7 0. 65 0. 04 73 0. 00 25 0. 10 94 0. 00 50 0. 01 68 0. 00 03 10 5. 4 4. 6 10 7. 3 1. 68 sh y4 01 -4 25 0. 51 39 7. 51 27 .1 4 0. 63 0. 04 63 0. 00 26 0. 10 57 0. 00 52 0. 01 65 0. 00 03 10 2. 0 4. 8 10 5. 7 1. 68 sh y4 01 -6 24 6. 88 38 0. 59 26 .4 0 0. 65 0. 04 87 0. 00 29 0. 11 27 0. 00 59 0. 01 68 0. 00 03 10 8. 4 5. 4 10 7. 2 1. 80 sh y4 01 -9 18 8. 96 30 2. 21 19 .8 5 0. 63 0. 05 01 0. 00 36 0. 10 95 0. 00 72 0. 01 59 0. 00 03 10 5. 5 6. 6 10 1. 4 1. 90 sh y4 01 -1 0 23 0. 68 43 2. 05 30 .5 2 0. 53 0. 04 63 0. 00 26 0. 10 89 0. 00 54 0. 01 70 0. 00 03 10 4. 9 4. 9 10 8. 9 1. 80 sh y4 01 -1 1 16 7. 08 28 8. 97 19 .8 8 0. 58 0. 04 50 0. 00 27 0. 10 29 0. 00 54 0. 01 66 0. 00 03 99 .4 5. 0 10 6. 1 1. 76 sh y4 01 -1 5 10 4. 77 14 4. 68 10 .4 2 0. 72 0. 04 63 0. 00 39 0. 11 05 0. 00 87 0. 01 73 0. 00 03 10 6. 4 7. 9 11 0. 6 2. 08 sh y4 01 -2 1 11 5. 88 18 7. 81 12 .4 0 0. 62 0. 05 32 0. 00 37 0. 11 61 0. 00 74 0. 01 58 0. 00 03 11 1. 6 6. 7 10 1. 2 1. 87 sh y4 01 -2 2 13 2. 51 14 7. 57 9. 96 0. 90 0. 04 93 0. 00 41 0. 10 99 0. 00 86 0. 01 62 0. 00 03 10 5. 8 7. 9 10 3. 4 2. 01 g eo lo gi a c ro at ic a geologia croatica 72 / special issue98 value is between 73-86, the solidification index (si) value is 4-12, and the harker diagram (fig. 6) shows that sio2 is significantly negatively correlated with feo, mgo, cao, al2o3, p2o5 and tio2 rocks may undergo crystallization differentiation evolution. the baocheng granites had a sio2 content range of 69.37– 72.42%, total alkali content (k2o + na2o) of 6.8–7.54%, and k2o/na2o ratios of 1.03–1.34. on the total alkali–sio2 diagram for intrusive rocks (middlemost, 1994; fig. 7), all samples fell within the granite field. all samples were plotted within the high-k calc-alkaline series domain on the sio2–k2o diagram (fig. 8a). the a/cnk–a/nk diagram shows that the majority of the samples fell within the weakly peraluminous rock domain (fig. 8b). the aluminum saturation index was 1.05–1.30%, and the rittmann index was σ = 1.75–1.95. 5.2.2. trace elements total rare earth element (∑ree) contents were 204.45–236.48 μg/g in the gaofeng intrusion, and lower (94.35–192.30 μg/g) in the baocheng intrusion. the (la/yb)n values of the granitic rocks from the two intrusions were 10.32–15.89 and 17.56–31.13, respectively. these values indicate a high degree of heavy ree/ light ree (hree/lree) fractionation and lree enrichment. the gaofeng intrusion had δeu values of 0.52–0.66 and a moderately negative eu anomaly; the baocheng granitic rocks had δeu(eu/eu*= n n neu / sm / gd ) values of 0.77–0.88, and show a weak negative eu anomaly. the ree partition pattern shows that the gaofeng and baocheng intrusions have basically consistent ree partition patterns of right-deviating curves (fig. 10a). the incompatible-elements spider diagram normalized on a primitive mantle (fig. 10b) shows that both the gaofeng and baocheng intrusions were enriched in large ion lithophile elements (lile), but depleted in high field-strength elements (hfse). enrichment of large ion lithophile elements (lile) such as rb, ba, sr and k, and loss of high field strength elements such as nb, ta, p and ti (fig. 7b), rb/sr value 0.32–0.80, k/rb value 180–250, is similar to the typical characteristics of granites related to subfigure 5. cathodoluminescent images and spot analysis points of zircon crystals from the hainan granite (a) oscillatory zircon from the gaofeng granite (b) oscillatory zircon from the baocheng granite. figure 6. results of in situ zircon 206pb/238u age dates (a) gaofeng granite (b) baocheng granite. g eologia c roatica xiaobo et al.: the characteristics of granites in the gaofeng and baocheng areas, hainan province, china ... 99 duction. it also indicates that there may be fractionation crystallization of apatite, ti-rich minerals, rutile and so on during magma evolution. on the mid-oceanic ridge standardized diagram, the gaofeng and baocheng intrusions were relatively similar to chilean granites (pearce et al., 1984), which is typical of an active continental-margin environment (fig. 10c). the sr content of the gaofeng rock mass is 191–356 ppm, averaging 277.25 ppm. the yb content is 2.35–2.93 ppm, (average 2.57 ppm) and the y content is 23.2–27.9 ppm (average 24.68 ppm); the sr content of baocheng rock mass is relatively higher at 327431 ppm with an average of 396.75 ppm, and the yb content is relatively lower at 0.75–1.75 ppm, (average 1.06 ppm). the y content is relatively lower at 5.6–17.5 ppm, (average 9.5 ppm). peak sr/y value ranges from 8.23–15.15, average 11.3, sr/yb value 23.2–27.9, average 24.68; baocheng sr/y value 23.54–76.96, average 50.05, sr/yb value 235.43–552.56, average 414.68. the overall characteristics show higher sr and lower yb, y content and higher sr/yb, sr/y ratios. the characteristics of high sio2, high al2o3, mg# value is 41-44, high sr, low y and yb, high sr/y and sr/yb, and weak eu negative abnormity are similar to those of adakites representing the source of the subduction slab (stern & kilian, 1996; wang et al., 2006; sheppard et al., 2001), which is also consistent with the characteristics of active continental margins represented by rare earth and trace elements. figure 7. sio2 versus k2o+na2o diagram for intrusive rocks (middlemost, 1994; irvine & baragar, 1971). figure 9. harker diagram of the gaofeng and baocehng granites. figure 8. the classification of the gaofeng and baocehng granites: (a) sio2 versus k2o diagram (after peccerillo & taylor, 1976); (b) a/cnk versus a/nk diagram (after maniar & piccoli, 1989). g eo lo gi a c ro at ic a geologia croatica 72 / special issue100 6. discussion 6.1. rock type and genesis the i-, s-, m-, and a-type classification scheme (pitcher, 1983) has been generally accepted as a classification scheme for granites. m-type granites that formed during mantle magma evolution are very rare, and represent an oceanic island-arc tectonic environment. considering the regional tectonic setting of hainan island during the cretaceous, m-type granites are not represented in the granites studied here. hence, the granites of the southern hainan province are mainly represented by i-, s-, and a-types. fig. 11a shows that most of the samples are undifferentiated i-, s-, and a-types. iand s-type granites can be discriminated using p2o5 and p2o5–sio2 diagrams (fig. 11b). the p2o5 content decreases with increasing sio2 content, resulting in a negative correlation; this relationship is consistent with the evolution of itype granites, and is markedly different from s-type granites. the major element characteristics of the granites from this study indicate that these rocks are metaluminous to weakly peraluminous, with obvious hree/lree fractionalization, lree enrichment, and hree depletion. the trace element characteristics included lile enrichment and a depletion of ta, nb, and ti and other hfse, suggesting that the granites had signatures of island-arc granites. in addition, laboratory petrological research implied that partial melting of intermediate-basic rocks in the crust formed metaluminous granitoids with a more basic chemical composition (wolf et al., 1994; beard et al., 1991; johannes et al., 1996; sisson et al., 2005). the source rocks of these granitoids may have been derived from partial melting of island-arc volcanic rocks, or comagma of island-arc volcanic rocks. 6.2. petrogenesis and source characteristics it is a widely accepted fact in the literature that i-type granite is a product of crust-mantle mixed source magmatism (bergantz, 1989; petford & cruden, 2000; zhou & li, 2000; annen & sparks, 2002). the gaofeng and baocheng granites are characterized by their high sr, low yb and y, high sr/yb and (la/yb) n ranging from 15-31 ppm which is very simi lar to adakites (wang et al., 2012; jia et al., 2010). mantle source characteristic identification charts are shown in fig. 12a-c. it can be seen in fig. 12a-c, that the sio2-mg# variable diagram, sio2-mgo variable diagram, and ba/th-nb/zr variable diagram show that the source area is related to plate subduction. identification of hornblende, the hydrous mineral in the sample, confirms that the studied rocks originate from subducted plates. there are two possible models for genesis of i-type granites from the mantle (qiu et al., 2008). the first model includes mixing between the mantle derived magma and felsic magma from the crust. the second model is where the mantle-derived magma first intrudes into the crust to form the primary crust. then, this mixed crustal rock which consists of both primary crust and the ancient basement crust is partially melted under the influence of later thermal events. the nb/la ratios of the gaofeng and baocheng granites described here are close to the crust except for the samples which occur in the plate melting zone as presented in fig.12a-b. the rest of the samples are distributed near the component lines affected by the afc indicating that these granites have not originated directly from melting of a mantle-derived subduction plate. this is more consistent with the second model as explained above. these findings also confirm similar reports figure 10. normalized diagrams of the gaofeng and baocehng granites: (a) ree patterns; (b) incompatible element spidergrams; (c) ocean ridge granite (org) granite normalized patterns (chondrite ree values and primitive mantle-normalized values from sun & mcdonough (1989); khoshnoodi et al. (2017) ; org and chile granite values from pearce et al. (1984). figure 11. sample classification using diagrams of (a) (zr+nb+ce+y) vs. (k2o+na2o)/cao (whalen et al., 1987); (b) p2o5 vs. sio2 variation (chappell & white, 1992). g eologia c roatica xiaobo et al.: the characteristics of granites in the gaofeng and baocheng areas, hainan province, china ... 101 previously published in the literature (pitcher et al., 1985; wu et al., 2003b). according to ge et al. (2003) and tang et al. (2014), basic intrusive rocks with strong arc features in the same area and in the same geological time period (i.e., early and late cretaceous in the southern of hainan) have the same geochemical characteristics as those of the gaofeng and baocheng intrusive rocks. these similar characteristics include high sr-rich k, high k/tilow ti, low y and yb, no negative eu anomalies, rb/sr, nb/la ratios, enrichment of large ion lithophile elements and high field strength element loss. basic intrusive rocks originated from the melting of subducted plates (tang et al., 2014). it can be inferred that the mantle-derived components of the gaofeng and baocheng granite magmas may have similar or identical source areas with the basic intrusive rocks. the primary crust and the basic intrusive rocks mentioned above in the second model may be products of the same source area. their only difference is the depth of intrusion. according to tang et al. (2014), the basic intrusive rocks are derived from the garnet phase. it is speculated here that the primary crust originates from the garnet phase. magma differentiation index (di) and solidification index (si) values of the gaofeng and baocheng granites range from 73 to 86 and from 4 to 12, respectively. in addition, sio2 is negatively correlated with feo, mgo, cao, al2o3, p2o5, and tio2. it can be concluded here that crystallization differentiation took place during magmatism. the negative anomalies between nb, ta, ti, p, and sio2 are negatively correlated with nb/nb* (nb*=2nbn/(kn+srn) (fig. 12d). this indicates that the negative anomalies are mainly caused by crustal afc (ma et al., 2004). the above characteristics confirm the occurrence of ilmenite, rutile, and apatite separation crystallization during magma evolution. the negative anomaly of ba does not represent the separation and crystallization of potassium feldspar. this is because there is a positive correlation between k2o and sio2 in the huck diagram (fig. 9) and there is only a slight negative anomaly of the eu element. it is inferred from the insignificant negative sr anomaly that there is no or little separation crystallization of plagioclase. this shows that there is little or no separation of potassium feldspar and plagioclase during magmatic evolution. in summary, the characteristics and evolution process of the source area of the gaofeng and baocheng granites are as follows: the partially melted garnet phase affected by the subduction of plates intrudes into the bottom of the crust to form a primary crust with a higher basic composition. the mixed crust formed by the primary crust and the ancient crust partially melts to form a granitic magma. the mixed magma rises and emplaces in the crust with differential crystallization of minerals such as apatite, ilmenite, and rutile. figure 12. the characteristics of magma source and evolution: (a) mg#-sio2 diagram (after stern & kilian,1996); (b) sio2-mgo diagram (after wang et al., 2006); (c) ba/th-nb-zr diagram (abratis, 2001); (d) sio2-nb/nb* diagram (after ma et al., 2004). g eo lo gi a c ro at ic a geologia croatica 72 / special issue102 table 3. major (wt%) and trace element (μg/g) abundances of representative samples from the gaofeng and baocheng suites. gaofeng baocheng sample yl501 yl601 yl701 yl703 shy101 shy201 shy302 shy401 sio2 65.90 71.45 69.05 69.74 72.42 71.76 72.21 69.37 tio2 0.71 0.27 0.52 0.45 0.25 0.32 0.28 0.34 al2o3 15.32 14.32 14.67 14.51 14.63 14.57 14.39 15.80 fe2o3 1.42 1.42 1.24 0.82 0.87 0.97 1.01 1.14 feo 2.61 1.00 1.84 1.89 0.69 1.03 0.86 0.98 mno 0.07 0.06 0.06 0.05 0.03 0.04 0.04 0.03 mgo 1.64 0.54 1.20 1.10 0.58 0.81 0.79 0.89 cao 3.51 1.71 2.52 2.54 1.58 2.14 1.89 1.70 na2o 3.21 3.44 3.08 3.01 3.19 3.63 3.45 2.99 k2o 4.08 4.69 4.59 4.83 4.27 3.74 4.09 3.81 p2o5 0.16 0.08 0.11 0.10 0.06 0.09 0.07 0.08 loi 1.20 0.88 1.00 0.85 1.32 0.76 0.77 2.70 total 99.84 99.86 99.89 99.89 99.90 99.87 99.85 99.85 alk 7.29 8.13 7.67 7.84 7.47 7.37 7.54 6.80 a/nkc 0.95 1.03 1.00 0.98 1.15 1.05 1.06 1.30 σ 2.32 2.32 2.26 2.30 1.89 1.89 1.95 1.75 rb 159.00 153.00 207.00 222.00 173.00 162.00 174.00 137.00 sr 356.00 191.00 270.00 292.00 327.00 412.00 413.00 431.00 ba 724.00 719.00 755.00 720.00 705.00 778.00 825.00 858.00 y 23.50 23.20 27.90 24.10 6.40 17.50 8.50 5.60 nb 16.30 12.40 18.10 16.50 8.50 11.00 9.60 9.20 ta 1.35 1.23 1.70 1.83 0.71 1.12 0.90 0.73 zr 274.00 160.00 256.00 220.00 125.00 152.00 141.00 169.00 hf 17.00 7.65 14.20 13.00 5.88 8.79 7.37 8.96 th 18.00 14.00 25.30 25.40 61.00 17.60 12.70 24.20 u 4.10 2.30 5.70 5.10 7.80 6.80 5.30 3.90 la 50.40 57.10 42.20 46.70 24.90 57.30 23.10 33.80 ce 96.90 103.00 85.30 92.20 40.90 69.70 46.70 57.00 pr 11.00 11.50 10.40 10.70 4.71 10.40 5.26 6.21 nd 39.00 39.60 38.40 38.20 15.40 34.10 18.00 19.20 sm 6.68 6.41 7.09 6.70 2.39 5.66 2.82 2.78 eu 1.37 1.14 1.22 1.07 0.64 1.35 0.75 0.69 gd 5.80 5.53 5.92 5.61 1.95 4.84 2.37 2.29 tb 0.85 0.81 0.93 0.87 0.26 0.71 0.31 0.28 dy 4.65 4.59 5.36 4.88 1.28 3.62 1.60 1.38 ho 0.89 0.86 1.01 0.89 0.24 0.64 0.29 0.24 er 2.42 2.44 2.75 2.37 0.68 1.66 0.83 0.70 tm 0.41 0.42 0.49 0.42 0.12 0.28 0.14 0.12 yb 2.35 2.58 2.93 2.41 0.75 1.75 0.95 0.78 lu 0.34 0.42 0.44 0.35 0.13 0.26 0.16 0.12 ∑ree 222.97 236.48 204.45 213.37 94.35 192.30 103.25 125.46 (la/yb)n 15.38 15.89 10.32 13.89 23.83 23.46 17.56 31.13 δeu 0.66 0.57 0.56 0.52 0.88 0.77 0.86 0.81 rb–(y+nb), and rb–(yb+ta) trace elements discrimination diagrams demonstrate that the samples were volcanic-arc granites. some of the above features correspond to those of a continental margin arc as follows: early cretaceous andesite and rhyolite widely exposed in southern hainan show typical continental margin arc characteristics (qiang, 2016; han, 2017). the clastic compositions, chemical compositions and sedimentary structural characteristics of the lower cretaceous lumuwan formation and the upper cretaceous baowan formation all indicate that sedimentation took place in the continental margin arc setting. the age of the detrital zircon assemblage especially indicates that strong compression and uplift occurred at the turn of early and late cretaceous in the southern qiongnan area, and this tectonic activity lasted until the middle of the late cretaceous 6.3. tectonic setting the major element characteristics of the gaofeng and baocheng intrusions indicate the rocks are high-k calc-alkaline series. the source areas of high-k calc-alkaline series are related to previous subduction (liegeois et al., 1998). the trace-element spider diagram of the gaofeng and baocheng intrusions indicates typical negative nb, ti, and ta anomalies, which are similar to the characteristics of island-arc granites. similarly, the mid-oceanic ridge standardized diagram shows that the gaofeng and baocheng intrusions had trace element characteristics similar to those of active continental-margin rocks. on the rb/30-hf-ta×3 diagram (fig. 14), the gaofeng and baocheng intrusions were located within the volcanic-arc granite domain. similarly, according to pearce’s granite tectonic setting discrimination diagram (fig. 13), the nb–y, ta–yb, g eologia c roatica xiaobo et al.: the characteristics of granites in the gaofeng and baocheng areas, hainan province, china ... 103 figure 13. tectonic discrimination diagrams. (a)–(c) after pearce et al. (1984); (d) after harris et al. (1986); (org – ocean ridge granites; wpg – within plate granites; vag – volcanic arc granites; syn-colg – syn-collision granites). figure 14. discriminant diagrams of the tectonic setting (a) r1 vs r2 (after batchelor & bowden, 1985); (b) rb/30-hf-ta×3 (harris et al.,1986,) (org – ocean ridge granites; wpg – within plate granites; vag – volcanic arc granites; syn-colg – syn-collision granites). g eo lo gi a c ro at ic a geologia croatica 72 / special issue104 (tang, 2014). in addition, yun (2004) identified the late stage of the yanshan granites represented by the tunchang intrusion in hainan island as acg-type granites, which are typical subduction granites (xiao, 2002). their arc characteristics are widely recognized by almost all scholars who study late mesozoic magmatic rocks in hainan island, judging by the published literature referenced herein. jiang & li (2014) considered that hainan island was an andean continental margin arc tectonic environment before 73ma in the late mesozoic. moreover, the northward subduction compression tectonics of the ancient sea provided a necessary high-pressure environment. as a result, the hainan province was located in an oceaniccrust subduction tectonic setting in the late yanshanian period, which would have been an andean-type continental margin arc environment. this conclusion contradicts the view that magmatism occurred in an extensional setting (ge et al., 2003; yun et al., 2003; chen et al., 2008). 6.4. implications for regional geology the cretaceous magmatism of hainan island and the fujian and zhejiang areas was thought to have been related to western pacific subduction (wang et al., 2012; jia et al., 2010; tang et al., 2014; mao et al., 2013; li et al., 2013; wang et al., 2012). however, the cretaceous granites on hainan island displayed geochemical signatures different to those of the coeval granites from the fujian and zhejiang areas (fig. 15). specifically, the granites of hainan island have the characteristics of high sr (335), low yb (1.8), low y (17.1), and high sr/y(20). although similar granite characteristics have also been reported from the fujian and zhejiang provinces (chen, 2014), it is not possible to explain formation of the granites of fujian and zhejiang and those of hainan island by the same mechanism. firstly, granites with high sr are too rare in fujian and zhejiang (zhang, 2014; jia et al., 2010). secondly, some of the granites in fujian and zhejiang are actually guangxi-type granites (zhang, 2014) with high sr and yb contents (chen, 2013, 2014; zhao, 2007; zhang, 2005), which differ from the high-sr, low-yb granites of hainan island. until now, the miarolitic granite widely distributed along the coast of zhejiang and fujian has not been found on hainan island. in addition, the majority of the granites in the late yanshanian in hainan island are i-type granites (wang et al., 1991).but the granites in fujian and zhejiang are composed of a-type and itypes, and the proportion of i-type granite is far less than that of the hainan island i-type granite in qiongzhou (jia et al., 2010; zhang, 2014; chen, 2013; zhao et al., 2007). source area and diagenetic evolution characteristics of the two diagenetic figure 15. geochemical diagrams showing a difference in granite between the hainan and zhejiang-fujian granites in the cretaceous (a) nk-nkc; (b) sr-yb, (after zhang, q., 2014); (c) r1 versus r2, r1=4si-11(na+k)-2(fe+ti), r2= 6ca+2mg+al, (after batchelor & bowden, 1985); (d) ta-rb-hf, (after harris et al., 1986) data from yun & xie (2003); jia et al. (2010); ge et al. (2003); tang et al. (2014); chen et al. (2013); chen et al. (2014); zhou & li (2000); li et al. (2013); qiu et al. (2008); thuy et al. (2004); nguyen et al. (2004); shellnutt et al. (2013). g eologia c roatica xiaobo et al.: the characteristics of granites in the gaofeng and baocheng areas, hainan province, china ... 105 models for i-type granite, the granite in zhejiang and fujian provinces is typical for the first one (qiu et al., 2008, 2012; zhao et al., 2012), and the granite of hainan island belongs to the second species discussed above. sr-nd isotopes also show great differe nces, indicating different magma sources (ge et al., 2003; tang et al., 2014). this shows that there are fundamental differences in the characteristics of the magma sources and the diagenesis of granites between the two places. the above understanding of the differences between granites from hainan island and fujian-zhejiang area is in agreement with wang (1991), who clearly pointed out that the granites in the coastal areas of fujian and guangdong are different from the contemporary granites in hainan island. therefore, when discussing the tectonic setting of yanshanian granite formation in hainan island, the important influence of oceanic crust subduction is clearly affirmed, though any claim that the ocean crust belongs to the western pacific ocean is not conclusive here. if fujian, zhejiang, and hainan island have been affected by western pacific subduction during the cretaceous, then granites with high sr/high yb and low sr/high yb, similar to those in the zhejiang and fujian area, should also be present in hainan island. the low-sr, high-yb granites that widely occur in fujian and zhejiang and the high-sr, low-yb granites of hainan island represent two different tectonic domains. there are significant differences in the sr-nd isotopic composition between the regions which indicate that the magmas come from different sources (tang et al., 2010). it was previously thought that the cretaceous granites that formed a record of subduction in fujian and zhejiang resulted table 4. comparison of the geological characteristics of the hainan and zhejiang-fujian granites. age（ma） type asd td dd zst hainan zj-fj hainan zj-fj hainan zj-fj hainan zj-fj hainan zj-fj 110-100 i-type i-type 100ma — sh ph e-w ne-sw 720-770℃ 774-819℃100-90 i-type a-type — — sl 90-70 — a-type — 80-72ma asd:the age of associated deposit;td:temperature and depth of rocks generate;dd:distribution direction of intrusions;sh:shallow & high temperatures;ph:plutonic & high temperatures;sl:shallow & low temperatures;zst:zr saturation temperature;zj:zhejiang; fj:fujian.data from tang(2010);chen(2014);yun et al.,(2004);zhou et al.(1991);li et al. (2013);ge et al. (2003);zhao et al.(2012);kang et al.(2018). figure 16. the cretaceous marginal arc of hainan island and its adjacent tectonic setting. g eo lo gi a c ro at ic a geologia croatica 72 / special issue106 from western pacific subduction. the influence of the western pacific subduction was confined to the east of wuyi mountain, however, hainan is located to the far west of wuyi mountain, therefore the influence of western pacific subduction could not have reached hainan island. zhu et al. (2002) & zhu (2004) believe that the farthest effects of the pacific plate subduction occur in the mariana arc, simply because the remaining oceanic crust of late mesozoic morb found in the mariana arc belongs to the indian ocean-tethys type. this also suggests that the subduction plates of mantle components during the diagenesis of granites may not originate from the palaeo-pacific plate. as a result, the hainan island granites were basically not affected by western pacific subduction. instead they were influenced by the northward-subducting ancient sea in the same location as the present-day south china sea, prior to the opening of the area during the late mesozoic (taylor & hayes, 1983; zhou, 1992; li, 1987; yao et al., 1994; xia et al., 2000; yan et al., 2005; min et al., 2010; lu et al., 2014). the late mesozoic granites of hainan island have similar geochemical characteristics to granites from the pearl river mouth basin and south vietnam (fig. 15). hainan island and zhejiang-fujian area both had similar tectonic settings (i.e., active continental margin) in the late mesozoic. however, there have been differences in the chemical composition of granite, the nature of the source area, magmatic processes involved, and the time series of tectonic evolution. the continental margin arc represented by hainan island should be a convergent boundary. it extends westward to reach yazhuang, suihe and other places in southern vietnam, and eastward to the pearl river mouth basin, fig. 16). according to data from previous studies, the northern shelf of the south china sea, hainan island, and suihe-yazhuang, after restoring their geo-historical position, were where the pearl river mouth basin is located. this is backed up by their very similar cretaceous granite and volcanic rock assemblages, and can be connected to the east-west andean continental margin arc (mo & shi, 1987; nguyen et al., 2004; thuy et al., 2004; liang, 2013; fang, 2016). according to tapponier’s model (1986), the indo-china block has slid 650–1200 km southeastward along the red river fault since the late eocene (yang et al., 1998; leloup et al., 1995; watkinson et al., 2011; scharer et al., 1994). if modeling this backwards in time, south vietnam should be along a line stretching westward from hainan island and the pearl river mouth basin. the above three sites constitute a latitudinal zone likely representing the active margin of the ancient sea differing from the pacific system. this ancient sea existed before the expansion of the presentday south china sea and was roughly equivalent to it, which was close to hainan island. fang (2016) named it as the “tethys south china sea” after subducting northward and closing the ancient sea area in the late mesozoic. whether the tethys domain really exists in the study area or not, much more detailed and special investigation is required. according to xia & huang (2000); yan & zhou (2001); zhu et al. (2004); liu et al. (2004); yan (2005), there should be traces of tethys in the northern waters of the south china sea. although the issue of tethys is not the main point discussed here, we call the northward subduction of oceanic crust (hainan island facing) in the late mesozoic as the “tethyan south china sea” for convenience of description. based on the present findings, the palaeo-sea area facing hainan island in the late mesozoic subduction to the north and the palaeo-pacific area subducted to the west belong to different tectonic settings. the disappeared palaeo-sea area is what we refer to here as the “tethyan south china sea”. furthermore, the late yanshanian tunchang intrusion of hainan island was composed of acg-type granitoid (yun & xie, 2003). typically, acg-type granites are granitoids formed in a subduction-zone setting (xiao et al., 2002). there were different rock types, varying ages, and other contrasting elements between the hainan and zhejiang-fujian locations (table 4). hainan island was more readily affected by subduction of the ancient sea than by subduction of the western pacific (fig. 16). in summary, the “tethys south china sea” facing hainan island subducted northward, and the subducted slabs entered the garnet peridotite phase and melted at the base of and intruded into the lower part of hainan island to form the primary crust. another part of the melt was intruded into higher positions along deep and large faults to form basic dykes. with the subduction, the mixed crust formed by the primary crust and the ancient basement crust were partially melted and further intruded into the granitic rocks. with the further intensification of subduction and compression, the crust and therefore the granite was also uplifted and exposed to the surface and denuded at the same time. with the subduction of the ancient sea, the denuded granite particles were transported and deposited in the sedimentary strata. the occurrence of zircon is reported in the late cretaceous strata of hainan island and southeast qiong basin during the early and late cretaceous. 7. conclusions 1) high-precision u-pb zircon dating results indicate that the gaofeng and baocheng granites in hainan island crystallized at~107ma and ~105ma. 2) the gaofeng and baocheng plutons are high-k calc-alkaline i-type granites, resembling magmatic rocks formed in a continental arc setting. 3) the granites of hainan island displayed geochemical signatures differing from those of coeval granites in the fujian and zhejiang areas. both represented different subduction tectonic domains. the fujian and zhejiang areas were affected by western pacific subduction, hainan island was more readily affected by subduction of the tethyan south china sea. acknowledgement financial support for this research was provided by the national natural science foundation of china (no. 41572207, no. 41276047, no. 41030853) references barr, s.m. & macdonald, a.s. (1981): geochemistry and geochronology of late cenozoic basalts of southeast asia.– bull. geol. soc. am. (part ii), 92/8, 1069–1142. doi: 10.1130/gsab-p2-92-1069 batchelor, r.a. & bodwen, p. (1985): petrogenetic interpretation of granitoid rock series using multicationic parameters.– chemical geol., 48/1, 43–55. doi: 10.1016/0009-2541(85)90034-8 beard, j.s. & lofgren, g.e. (1991): dehydration melting and water-saturated melting of basaltic and andesitic greenstones and amphibolites at 1–3 and 6–9 kbar.– journal of petrology, 32/2, 365–402. belousova, e.a., griffin, w., o’reilly, s.y. & fisher, n.i. (2002): igneous zircon: trace element composition as an indicator of source rock type.– contr. mine ral. petrol., 143/5, 602–622. doi: 10.1007/s00410-002-0364-7 ben-avraham, z. & uyeda, s. (1973): the evolution of the china basin and the mesozoic paleogeography of borneo.– earth. planet. sci. lett., 18/2, 365–376. doi: 10.1016/0012-821x(73)90077-0 castillo, p.r., janney, p.e. & solidum, r.u. (1999): petrology and geochemistry of camiguin island, southern philippines: insights to the source of adakites g eologia c roatica xiaobo et al.: the characteristics of granites in the gaofeng and baocheng areas, hainan province, china ... 107 and other lavas in a complex arc setting.– contrib. mineral. petrol., 134/1, 33−51. doi: 10.1007/s004100050467 chappell, b.w. & white, a.j.r. (1992): iand s-type granites in the lachlan fold belt. transactions of the royal society of edinburgh.– earth sciences, 83/1–2, 1–26. chen, j.y., yang, j.h., zhang, j.h. & sun, j.f. (2014): geochemical transition shown by cretaceous granitoids in southeastern china: implications for continental crustal reworking and growth.– lithos, 196–197, 115–130. doi: 10.1016/j.lithos.2014.03.003 chen, j.y., yang, j.h., zhang, j.h., sun, j.f. & wilde, s.a. (2013): petrogenesis of the cretaceous zhangzhou batholith in southeastern china: zircon u–pb age and sr–nd–hf–o isotopic evidence.– academic annual meeting of institute of geology and geophysics, chinese academy of sciences, (13th). chen, m.l. (2014): petrogenesis of the qian jia composite pluton in hainan island and its relationship to mo polymetallic mineralization.– china. phd thesis, china university of geosciences, 132 p. chen, m.l., li, s.x., zeng, y.l. & zhou, j.b. (2008): petrochemical characteristics and metallogenic analysis of the cretaceous qianjia rock bodies in hainan island.– mineral resources and geology, 22/1, 36–42 (in chinese with english abstract). chen, w.f., chen, p.r., xu, x.s. & zhang, m. (2005): the geochemical characteristics of basalts in south china and its restriction on pacific plate subduction. science in china-ser. d., earth sciences, 48/12, 2104–2117. defant, m.j. & drummond, m.s. (1990): derivation of some modern arc magmas by melting of young subducted lithosphere.– nature, 347/6294, 662–665. doi: 10.1038/347662a0 fang, n.q. (2016): a new model on the mesozoic “south china sea” (scs): reconstructing the hainan marginal arc and recognizing the tethyan scs.– earth science frontiers, 23/6, 107–119. ge, x.y., li, x.h. & zhou, h.w. (2003): geochronologic, geochemistry and sr-nd isotopes of the late cretaceous mafic dyke swarmsin southern hainan island.– geochimica, 32/1, 11–20 (in chinese with english abstract). guo, l.z. (1984): granitoids in southeastern china: their time–space distribution, tectonic framework and evolution.– science technology publishers, jiangsu, 38–48. han, q. (2016): the basic characteristics of mesozoic-cenozoic rhyolites in the northern margin of the south china sea.– master thesis, school of ocean sciences, china university of geosciences (beijing), 69 p. (in chinese with english abstract). harris, h.b.w., pearce, j.a. & tindle, a.g. (1986): geochemical characteristics of collision zone magmatism.– collision tectonics, 19/5, 67–81. doi: 10.1144/gsl. sp.1986.019.01.04 hou, z.q., gao, y.f., meng, x.l., qu, x.m. & huang, w. (2004): genesis of adakitic porphyry and tectonic controls on the gangdese miocene porphyry copper belt in the tibetan orogen.– acta petrologica sinica, 20/2, 239–248. hung, v.n. (1999): tin potential of high-aluminium granites (datanky and ankroetplutons) from the dalat zone (in vietnamese).– msc thesis, national university of ho chi minh hutchison cs geological evolution of southeast asia. clarendon, oxford. irvine, t.n. & baragar, w.r.a. (1971): a guide to the chemical classification of the common volcanic rocks.– canadian journal of earth sciences, 8, 523–548. doi: 10.1139/e71-055 jia, y. & di, z. (2001): advancement on the meso-tethys along the northern margin of the south china sea.– marine geology & quaternary geology, 21/4, 49–54. jia, x.h., wang, q., tang, g.j. & jiang, z.q. (2008): geochemical characteristics and genesis of intrusive rocks related to mo-mineral in tunchang area, hainan.– bull. mineral. petrol. geochem. 27 (suppl.), 307−309 (in chinese). jia, x.h., wang, q. & zhao, w.q. (2010): zircon u-pb geochronology, geochemistry and petrogenesis of the late early cretaceous adakitic intrusive rocks in the tunchang area, hainan province.– geochimica, 39/6, 497–519 (in chinese with english abstract). johannes, w. & holtz, f. (1996): petrogensis and experimental petrology of granitic rocks.– springer berlin heidelberg, 335 p. kang, c. et al. (2018): petrogenesis of tiangongshan indosinian granites in longyan area, southwest fujian.– earth science, 43/12, 4621–4637. kay, r.w. (1978): alertian magnesian andesite: melts from subducted pacific ocean crust.– volcano. geotherm. res., 4/1–2, 117–132. khoshnoodi, k., behzadi, m., gannadi-maragheh, m. & yazdi, m. (2017): alkali metasomatism and th-ree mineralization in the choghart deposit, bafq district, central iran.– geologia croatica, 70/1, 53–69. doi: 10.4154/ gc.2017.03 leloup, p.h. (1995): the ailao shan-red river shear zone (yunnan, china), tertiary transform boundary of indochina.– tectonophysics, 251/1–4, 3–10. li, t.g. (1987): determination and study of density and magnetism of rock of the coast and the islands of the northern south china sea.– marine geology & quaternary geology, 7/3, 57–69 (in chinese with english abstract). li, l.l., zhou, h.w., chen, z.h., wang, j.r., chen, z.h. & chen, w. (2013): petrogenesis of the late mesozoic granitic rocks in southeast coastal areas of fujian province and its geological significance.– geological bulletin of china, 32/7, 1047–1062 (in chinese with english abstract). li, x.h., zhou, h.w., ding, s.j., li, j.y., zhang, r.j., zhang, y.m. & ge, w.c. (2000): hainan island mid-ocean ridge type metamorphic rock: the ancient tethys oceanic crust fragment? – chinese science bulletin, 45/1, 84–88 (in chinese). liegeois, j.p., navez, j., hertogen, j. & black, r. (1998): contrasting origin of post-collisional high-k calc-alkaline and shoshonitic versus alkaline and peralkaline granitoids. the use of sliding normalization.– lithos, 45/1–4, 1–28. doi: 10.1016/s0024-4937(98)00023-1 ling, l.h., pin, y. & you, z.b. (2004): pre-cenozoic basements of the south china sea and eastern tethyan realm.– marine geology & quaternary geology, 24/1, 15–28. lu, b.l., wang, p.j., liang, j.s., sun, x.m. & wang, w.y. (2014): structural properties of paleo-south china sea and their relationship with the tethys and the paleo-pacific tectonic domain.– journal of jilin university; earth science edition, 44/5, 1441–1450 (in chinese with english abstract). ludwig, k.r. (2003): isoplot 3.00: a geochronological toolkit for microsoft excel.– berkeley geochronology center special publication 4, berkeley. ma, c.q., ming, h.l. & yang, kg. (2004): an ordovician magmatic arc at the northern foot of dabie mountains: evidence from geochronology and geochemistry of intrusive rocks.– acta petrologica sinica, 20/3, 393–402. macpherson, c.g., dreher, s.t. & thirlwall, m.f. (2006): adakites without slab melting: high pressure differentiation of island arc magma, mindanao, the philippines.– earth planet sci. lett., 243/3–4, 581−593. doi: 10.1016/j.epsl.2005.12.034 mahoney, j.j., frei, r., tejada, m.l.g., mo, x.x., leat, p.t. & nagler, t.p. (1998): tracing the indian ocean mantle domain through time: isotopic results from old west indian, east tethyan, and south pacific seafloor.– journal of petrology, 39/7, 1285–1306. doi: 10.1093/petroj/39.7.1285 maniar, p.d. & piccoli, p.m. (1989): tectonic discrimination of granitoids.– geological society of america bulletin, 101/5, 635–643. doi: 10.1130/0016 -7606(19 89)101%3c0635:tdog%3e2.3.co;2 mao, j.r., ye, h.m. & li, z.l. (2013): magmatism and mineralization record of extrusion-extensional tectonics of late mesozoic in qin hang suture-zone.– acta mineralogica sinica, (s2), 30–31 (in chinese with english abstract). martin, h., smithies, r.h., rapp, r. & champion, d.c. (2005): an over view of adakite, tonalite-trondhjemite-granodiorite (ttg), and sanukitoid: relationships and some implications for crustal evolution.– lithos, 79/1–2, 1–24. metcalfe, i. (1988): origin and assembly of southeast asian continental terranes.– in: audley-charles mg, hallam a (eds.): gondwana and tethys, vol. 37. geol. soc. spec. publ., london, 101–118. metcalfe, i. (1996): pre-cretaceous evolution of se asian terranes.– geol. soc. spec. publ. london, 106/1, 97–122. doi: 10.1144/gsl.sp.1996.106.01.09 middlemost, e. (1994): naming materials in the magma/igneous rock system.– earth science reviews, 37/3–4, 215–224. doi: 10.1016/0012-8252(94)90029-9 min, h., ren, j.y., gao, j.y. & zuo, y.s. (2010): location of the ancient subduction zone in the northern south china sea and its constrains on the spreading of the south china sea basin.– geotectonica et metallogenia, 34/4, 599–605 (in chinese with english abstract). mo, y. & shi, y. (1987): paleomagnetic study and tectonic evolution of hainan terrane and its vicinal continental coast the late mesozoic to cenozoic.– journal of nanjing university (natural sciences), 23/3, 521–532. mungall, j.e. (2002): roasting the mantle: slab melting and the genesis of major au and au-rich cu deposits.– geology, 30/10, 915–918. doi: 10.1130/0091 -7613(20 02)030%3c0915:rtmsma%3e2.0.co;2 nguyen, t.t.b., satir, m., siebel, w. & chen, f. (2004): granitoids in the dalat zone, southern vietnam: age constraints on magmatism and regional geological implications.– international journal of earth sciences, 93/3, 329–340. doi: 10.1007/s00531-004-0387-6 pe-piper, g. & piper, j.w. (1994): miocene magnesian andesites and dacites, evia, greece: adakites associated with subducting slab detachment and extension.– lithos, 31/3–4, 125–140. doi: 10.1016/0024-4937(94)90004-3 pearce, j.a., harris, n.b.w. & tindle, a.g. (1984): trace element discrimination diagram for the tectonic interpretation of granitic rocks.– journal of petrology, 25/4, 956–983. doi: 10.1093/petrology/25.4.956 peccerillo, a. & taylor, s.r. (1976): geochemistry of eocene calc-alkaline volcanic rocks from the kastamonu area, northern turkey.– contributions to mineralogy and petrology, 58/1, 63–81. doi: 10.1007/bf00384745 petford, n. & atherton, m. (1996): na-rich partial melts from newly underplated basaltic crust: the cordillera blanca batholith, peru.– journal of petrology, 37/6, 1491–1521. doi: 10.1093/petrology/37.6.1491 okay, a.i., satir, m., maluski, h., siyko, m., monie, p., metzger, r. & akyz, s. (1996): paleoand neo-tethyan events in northwestern turkey: geog eo lo gi a c ro at ic a geologia croatica 72 / special issue108 logical and geochronological constraints.– in: yin a. & harrison t.m. (eds.): the tectonic evolution of asia, 111/3, 543–8. pitcher, w.s. (1983): granite type and tectonic environment.– in: hsuk (ed.): mountain building processes. academic press. london, 19–40. qiang, m.l. (2016): the basic characteristics of cretaceous andesites in the northern margin of south china sea and compare with the andesites of southeast china.– thesis master, school of ocean sciences, china university of geosciences (beijing), 53 p. (in chinese with english abstract). qiu, j., zhen, l.i. & liu, l. (2012): petrogenesis of the zhangpu composite granite pluton in fujian province: constraints from zircon u-pb ages, elemental geochemistry and nd-hf isotopes.– acta geologica sinica, 86/4, 561–576. qiu, j.s., xiao, e., hu, j., xu, x.s., jiang, s.y. & li, z. (2008): petrogenesis of highly fractionated i-type granites in the coastal area of northeastern fujian province: constraints from zircon u-pb geochronology, geochemistry and nd-hf isotopes.– acta petrologica sinica, 24/11, 2468–2484. scharer, u., zhang, l.s. & tapponnier, p. (1994): duration of strike slip movements in large shear zones: the red river belt, china.– earth and planet. sci. lett., 126/4, 379–397. doi: 10.1016/0012-821x(94)90119-8 sen, c. & dunn, t. (1994): dehydration melting of a basaltic composition amphibolite at 15 and 20 gpa: implications for the origin of adakites.– contributions to mineralogy and petrology, 117/4, 394–409. shellnutt, j.g., lan, c.y., long, t.v., usuki, t., yang, h.j. & mertzman, s.a. (2013): formation of cretaceous cordilleran and post-orogenic granites and their microgranular enclaves from the dalat zone, southern vietnam: tectonic implications for the evolution of southeast asia.– lithos, 12/182–183, 229–241. doi: 10.1016/j.lithos.2013.09.016 sisson, t.w., ratajeski, k., hankins, w.b. & glazner, a.f. (2005): voluminous granitic magmas from common basaltic sources.– contrib. mineral petrol., 148/6, 635–661. doi: 10.1007/s00410-004-0632-9 skjerlie, k.p. & patiño, douce, a.e. (2002): the fluid-absent partial melting of a zoisite-bearing quartz eclogite from 1-0 to 3-2 gpa: implications for melting in thickened continental crust and for subduction-zone processes.– journal of petrology, 43/2, 291–314. sorensen, s.s. & grossman, j.n. (1989): enrichment of trace elements in garnet amphibolites from a paleo-subduction zone: catalina schist, southern california.– geochimica et cosmochimica acta, 53/12, 3155–3177. doi: 10.1016/00167037(89)90096-3 sun, s.s. & mcdonough, w.f. (1989): chemical and isotopic systematic of oceanic basalts: implications for mantle composition and process.– in: sauders, a.d. and norry, m.j. (eds.): magmatism in the ocean basins. geological society special publication, 42, 313–345. doi: 10.1144/gsl.sp.1989.042.01.19 tang, l.m. (2010): magmatic evidence of two tectonic extension events during the mesozoic in hainan island & geodynamic implications.– phd thesis, zhejiang university, 118 p. (in chinese with english abstract). tang, z.y. (2014): approach to the sedimentological and geochemical characteristics of the cretaceous continental basins in northern margin of the south china sea. – thesis, master. school of ocean sciences, china university of geosciences (beijing), 65 p. (in chinese with english abstract). tang, l.m., chen, h.l. & dong, c.w. (2014): zircon u-pb dating and tectonic significance of late mesozoic granodiorite and its enclaves from hainan island.– chinese journal of geology, 49/1, 259–274 (in chinese with english abstract). tapponier, p., peltzer, g. & le dain, a.y. (1982): propagating extrusion tectonics in asia: new insights from simple experiments with plasticine.– geology, 10/12, 611–616. doi: 10.1130/0091-7613(1982)10%3c611:petian%3e2.0.co;2 taylor, b. & hayes, d.e. (1983): origin and history of the south china sea basin. the tectonic and geologic evolution of southeast asian seas and islands: part 2, 23–56. doi: 10.1029/gm027p0023 tien, p.c., an, l.d. & bach, l.d. (1991): geology of cambodia, laos and vietnam (geological map 1:1,000,000) and its explanatory note. geol. surv. vietnam. thi, p.t. (1985): metamorphic complexes of the socialist republic of vietnam.– in: lee sang man (eds.) l90–95 [explanatory text of the metamorphic map of south and east asia (1:1,000,000)]. cgmw-unesco. thuy, t.b.n., satir, m., siebel, w., vennenmann, t. & long, t.v. (2002): geochemical and isotopic composition constraints on the petrogenesis of granitoids from the dalat zone, southern vietnam.– asian earth sci., 23/4, 467–482. thuy, n.t.b., satir, m., siebel, w., vennemann,t. & long, t.v. (2004): geochemical and isotopic constraints on the petrogenesis of granitoids from the dalat zone, southern vietnam.– journal of asian earth sciences, 23/4, 467–482. doi: 10.1016/j.jseaes.2003.06.001 wang, d.y. (1998): preliminary study on genetic type and emplacement mechanism of granite in the yacheng-gaocheng area, south hainan island.– guangdong geology, 13/4, 13–17. wang, d.z. & zhou, x.m. (2000): characteristics and petrogenesis of late mesozoic granitic volcanic-intrusive complexes in southeastern china.– sciencepress, 6/4, 487–498. wang, q., li, x.h., jia, x.h., wyman, d., tang, g.j., li, z.x., ma, l., yang, y.h., jiang, z.q. & gou, g.n. (2012): late early cretaceous adakitic granitoids and associated magnesian and potassium-rich mafic enclaves and dykes in the tunchang-fengmu area, hainan province (south china): partial melting of lower crust and mantle, and magma hybridization.– chemical geology, 328/11, 222–243. wang, x.f., ma, d.q. & jiang, d.h. (1991): geology of hainan island: magmatite.– beijing: geology publishing house, 155–160 (in chinese). wang, y., zhang, q. & qian, q. (2000): adakite: geochemical characteristics and tectonic significances.– chinese journal of geology, 35/2, 251–256 (in chinese with english abstract). watkinson, i. et al. (2011): the timing of strike-slip shear along the ranong and khlong marui faults, thailand.– journal of geophysical research solid earth, 116(b9). doi: 10.1029/2011jb008379 whalen, j.b., currie, k.l. & chappell, b.w. (1987): a-type granites: geochemical characteristics, discrimination and petrogenesis.– contributions to mineralogy and petrology, 95/4, 407–419. doi: 10.1007/bf00402202 wolf, m.b. & london, d. (1994): apatite dissolution into peraluminous haplogranitic melts: an experimental study of solubilities and mechanisms.– geochimica et cosmochimica acta, 58/19, 4127–4145. doi: 10.1016/0016-7037(94)90269-0 xia, k.y. & huang, c.l. (2000): the discovery of meso-tethys sedimentary basins in the south china sea and their oil and gas perspective.– earth science frontiers, 7/3, 227–238. (in chinese with english abstract). xiao, q.h. (2002): the thinking and research methods of granite.– beijing: geological publishing house (in chinese). xiong, x.l., adam, j. & green, t.h. (2005): rutile stability and rutile melt hf-se partitioning during partial melting of hydrous basalt: implications for tt-g genesis.– chemical geology, 218/3–4, 339–359 (in chinese with english abstract). xu, d.r., liang, x.q. & tang, h.f. (2000): geochemical characteristics of metamorphic basic volcanics from the baoban group, western hainan and its tectonic implications. geotecton. metallogen., 24/4, 303–313 (in chinese with english abstract). xu, j.f., wang, q. & yu, x.y. (2000): geochemistry of high-mg andesites and adakitic andesite from the sanchazi block of the mian-lue ophiolitic mélange in the qinling mountains, central china: evidence of partial melting of the subducted paleo-tethyan crust.– geochemical journal, 34/5, 359–377. xu, j.f., wu, j.b., wang, q., chen, j.l. & cao, k. (2014): research advances of a-dakites and adakitic rocks in china.– bulletin of mineralogy, petrology and geochemistry, 33/1, 6–13 (in chinese with english abstract). yan, j.x. (2005): tectonic implications of marine mesozoic deposits from kalimantan and malay peninsula.– journal of tropical oceanography, 24/2, 26–32 (in chinese with english abstract). yang, s.f., yu, z.y., guo, l.z. & shi, y.s. (1989): differentiation of hainan terrane, the research of paleogeomagnetism and the significance of plate tectonics.– journal of nanjing university: natural sciences edition, 1/1–2, 38–46 (in chinese with english abstract). yang, z.y., jean, b., sun, z.m. & zhao, y. (1998): tertiary squeeze-out of the indo-china block and lithospheric evolution of the qinghai-tibetan plateau.– acta geologica sinica, 72/2, 112–125. yao, b.c., zeng, w.j., chen, y.z. & zhang, x.l. (1994): xisha trough of south china sea: an ancient suture. – marine geology & quaternary geology, 14/1, 1–10 (in chinese with english abstract). yuan, h.l., wu, f.y., gao, s., liu, x.m., xu, p. & sun, d.y. (2003): zircon u-pb geochronology, rare earth elements of cenozoic intrusion in northeast china.– chinese science bulletin, 48/14, 1511–1520 (in chinese). yun, p., wu, y.b. & xie, s.z. (2004): origin of rock-forming minerals from some late yanshanian granite bodies in hainan island.– geology and mineral resources of south china, 4, 1–8. yun, p. & xie, s.z. (2003): the genesis type of upper mesozoic tunchang rock body in hainan island and its tectonic significance.– guangdong geology, 18/4, 9–14 (in chinese with english abstract). zandt, g., gilbert, h., owens, t.j., ducea, m., saleeby, j. & jones, c.h. (2004): active foundering of a continental arc root beneath the southern sierra nevada in california.– nature, 431/7004, 41–46. doi: 10.1038/nature02847 zhang, g.s., wen, h.j. & qiu, y.z. (2004): geochemistry of the late mesozoic mafic dykes in western fujian province.– geochimica, 33/3, 243−253 (in chinese with english abstract). zhang, q. (2014): geodynamic implications of continental granites.– acta petrolo gica et mineralogica, 33/4, 785–798 (in chinese with english abstract). zhang, q., li, c.d., wang, y., wang, y.l., jin, w.j., jia, x.q. & han, s. (2005): mesozoic high-sr and low-yb granitoids and low-sr and high-yb granitoids in eastern china: comparison and geological implications.– acta petrologica sinica, 21/6, 1527–1537 (in chinese with english abstract). g eologia c roatica xiaobo et al.: the characteristics of granites in the gaofeng and baocheng areas, hainan province, china ... 109 zhang, q., wang, y., qian, q., yang, j.h., wang, y.l., zhao, t.p. & guo, g.j. (2001): the characteristics and tectonic-metallogenic significances of the adakites in yanshan period from eastern china.– acta petrologica sinica, 2/2, 36–44 (in chinese with english abstract). zhang, y.m., zhang, r.j., yao, h.z. & ma, g.g. (1997): the precambrian crustal tectonic evolution in hainan island.– earth sci., 22, 395–400 (in chinese with english abstract). zhao, j.l., qiu, j.s. & zhen, l.i. (2012): petrogenesis of the taiwushan granite pluton in fujian province: constraints from zircon u-pb ages and hf isotopes.– acta petrologica sinica, 28/12, 3837–3950. zhao, x.l., mao, j.r., chen, r., xu, n.z., zeng, q.t. & ye, h.m. (2007): zircon shrimp age and geochemical characteristics of the caixi puton in southwestern fujian province.– acta petrologica et mineralogica, 26/3, 223–231 (in chinese with english abstract). zhou, x.r., wu, k.l., yan, b.q., chen, a.g. & wu, z.t. (1991): the petrology and tectonic-magmatic dynamics mechanism of zhangzhou granite.– geoscience journal of graduate school, china university of geosciences, 5/2, 106–108. zhou, x.m. & li, w.x. (2000): origin of late mesozoic igneous rocks in southeastern china: implications for lithosphere subduction and underplating of mafic magmas.– tectonophysics, 326/3–4, 269–287. doi: 10.1016/s0040-1951(00)00120-7 zhou, z.y. (1992): transition from transform fault to subduction system: a pattern of continental accretion in southeast china and its adjacent areas.– shanghai geology, 1, 5–11 (in chinese with english abstract).  geologia croatica 68/2 113-122 10 figs. 1 tab. zagreb 2015 abstract sixteen dinosaur footprints are exposed along the upper-bedding surface of a single lower hauterivian limestone layer in palud cove (western istria, croatia). this footprint-bearing horizon is part of the thick mesozoic stratigraphic succession of the adriatic-dinaridic carbonate platform. the palud site section is characterized by peritidal (shallow subtidal to intertidal) limestone with several shallowing-upward cycles composed of mudstone, peloidal wackestone/packstone, peloidal packstone/grainstone and fenestral mudstone/wackestone with common geopetal infill. the early hauterivian age of these deposits is based on their microfossil content, which is dominated by ostracods, benthic foraminifera and calcareous green algae (dasycladales). the footprints are circular to elliptical in shape, with no distinct digit impressions (with one possible exception), and with average length of 26 cm. most footprints have a well-defined expulsion rim produced by the compression and displacement of the waterlogged substrate caused by the feet of the dinosaurs. all of the footprints are nearly the same shape and size, which indicates that they were produced by the same kind of trackmaker – likely a sauropod dinosaur. these animals left their footprints on the top of an intertidal and shallowing-upward succession during ephemeral subaerial exposure of the fine-grained carbonate sediment. keywords: dinosaur footprints, sauropods, lower hauterivian, palud, istria, croatia cretaceous strata of the palud site on the istrian peninsula are part of the adriatic-dinaridic carbonate platform succession (adcp – also referred to as the adriatic carbonate platform, see discussion in vlahović et al., 2005). the adcp was one of the largest mesozoic platforms in the mediterranean region (central tethys) and its strata now comprise a heavily deformed, 4-6.5 km thick, lower jurassic to paleocene succession of almost pure carbonate deposits. these strata are part of a thicker (4-8.5 km), predominantly carbonate succession deposited over >270 my (from at least the carboniferous to the late eocene), and which forms most of the present-day croatian karst (external or outer) dinarides. the sedimentary succession exposed in istria mainly consists of shallow water carbonates with a stratigraphic 1. introduction this paper represents the first detailed documentation of the palud dinosaur footprint locality from the lower cretaceous (lower hauterivian) strata exposed in the southern part of cape gustinja in palud cove, western istria, croatia (mezga et al., 2007a; fig. 1). the palud site is currently subjected to intensive physico-chemical and biological weathering and erosion due to its exposure within the intertidal zone along the coast of the adriatic sea (fig. 2). the site is also located in close proximity to the coastal tourist resorts and is relatively easily accessible. the prospects of site destruction due to possible vandalism and future rise in sea level drive the need for its detailed study and documentation. dinosaur footprints in the lower hauterivian deposits of palud cove in istria, croatia  aleksandar mezga, blanka cvetko tešović, vedrana pretković, nina jovanović and zlatan bajraktarević department of geology and paleontology, faculty of science, horvatovac 102a, zagreb, croatia; (amezga@geol.pmf.hr) doi: 10.4154/gc.2015.08 geologia croaticageologia croatica geologia croatica 68/2geologia croatica 114 range from the late middle jurassic to the eocene (velić et al., 2003). about twenty dinosaur footprint sites have been discovered to date in istria (dalla vecchia et al., 1993, 2000, 2001, 2002; dalla vecchia, 1994, 2013; mezga & bajraktarević, 1999, 2004; dalla vecchia & tarlao, 2000; mezga et al., 2006, 2007b, c). most of these sites have been examined and described in great detail, but no detailed documentation has yet been published for the palud site. this paper presents the results of the study on the horizon with footprints produced by a relatively large trackmaker in coastal environments of a large carbonate platform and now exposed in the lower part of the palud succession. besides a detailed description of the footprints and their interpretations, this study also includes the petrographic analyses of the carbonate microfacies, and the description of the microfossil asfigure 1: geographical location of the site. figure 2: the dinosaur footprint site in palud cove. arrows mark the extent and location on the upper bedding surface of the footprint bearing layer. the right arrow points to the main exposure with 15 footprints and the left one at the location of the isolated footprint (no. 16) to the northwest of the main area. mezga et al.: dinosaur footprints in the lower hauterivian deposits of palud cove in istria, croatia geologia croatica 115 semblages as support for the identification of the environments of deposition and the age of the footprint-bearing section. the palud cove locality represents a new piece of evidence for the presence of dinosaurs on the adcp during the early cretaceous (early hauterivian; mezga et al., 2007a). during the 1990’s, a. tarlao had already observed a possible footprint-bearing surface close to the palud channel (dalla vecchia et al., 2000). 2. geological setting the istrian peninsula is located in the northern part of the adriatic coastal region of croatia (fig. 1). geological literature on istria covers more than three centuries of research. the first detailed information about the geology of this region was presented in the explanatory notes to the basic geological map of croatia, the rovinj sheet 1:100.000 (polšak & šikić, 1973). detailed lithofacies and biofacies investigations of shallow water carbonates in istria started in the 1970s and the list of the most important references can be found in velić et al. (2003). the istrian succession is mainly composed of upper middle jurassic to eocene shallow water carbonates (velić et al., 2003), and to a lesser extent of eocene carbonate and siliciclastic rocks, and quaternary terra rossa and loess deposits. this succession can be divided into four sedimentary sequences or megasequences separated by important discontinuities representing subaerial exposure surfaces (tišljar et al., 1998; velić et al., 2003). the oldest bathonian–lowermost kimmeridgian megasequence is characterized by shallowingand coarsening-upward trends and by the appearance of regressive breccias. the kimmeridgian–early tithonian subaerial exposure horizon with bauxite deposits caps this megasequence. the second upper tithonian–upper aptian megasequence is very complex with regard to its facies heterogeneity and great thickness. deposition of this megasequence started with an oscillating transgression and the resulting peritidal shallowing-upward cycles. this megasequence is capped by the upper aptian deposits, which experienced a relatively rapid shallowing and subaerial exposure (velić et al., 2003). this regional exposure was a consequence of a relative sea-level fall caused by the interaction of eustatic changes and synsedimentary tectonics in the istrian part of the adcp, which resulted in variable duration of shallow-water conditions in different parts of the platform, as well as in the varying intensity of erosion of the aptian and barremian deposits (velić et al., 2003). the end of this megasequence was marked by the deposition of breccias and conglomerates with common blackened pebbles, interbedded with clay layers, representing swamp conditions. the overlying upper albian–upper santonian megasequence is more than 1000 m thick. it is composed of variable facies successions, including peritidal and other nearshore environments during the late albian, differentiation of sedimentary systems during the vraconian (latest albian) and cenomanian, drowned platform systems during the latest cenomanian and turonian (gušić &jelaska, 1993), and re-establishment of the shallow-water sedimentation during the late turonian, coniacian and santonian (velić et al., 2003). the fourth megasequence in istria comprises a relatively thick succession of carbonate and siliciclastic deposits of eocene age. the duration of subaerial exposure of the lower to upper cretaceous rocks prior to deposition of the lower eocene varies from area to area; different parts of the eocene succession were transgressively deposited on various units of the cretaceous basement because of the terrain differentiation caused by late cretaceous tectonics (matičec et al., 1996). the current study of the palud footprint site focuses on limestones that belong to the second transgressive– regressive megasequence (upper tithonian–upper aptian). although the palud site is relatively close (about 1 km) to another dinosaur footprint site (the gustinja locality; dalla vecchia et al., 2000), a fault zone located at the tip of cape gustinja separates the two localities and prevents their correlation. therefore, palud and gustinja are considered to represent two separate and distinct localities. 3. lithology and biostratigraphy the lower cretaceous carbonate succession of the palud bay is characterized by peritidal (shallow subtidal to intertidal) limestones with several shallowing–upward cycles (fig. 3). these cycles are composed of mudstones, peloidal wackestones/packstones, peloidal packstones/grainstones (fig. 4a) and fenestral mudstones to wackestones (fig. 4b). the dinosaur footprints are observed in a layer of fenestral mudstone with common geopetal infill (fig. 4c). the microfossil assemblage present within these limestones is dominated by ostracods associated with the following foraminifera: istriloculina cf. elliptica (iovcheva) (figs. 4d, e); praechrysalidina cf. infracretacea luperto sinni (figs. 4f, g); vercorsella sp., rumanoloculina cf. robusta (neagu) (fig. 4h); mayncina bulgarica laug, peybernès & rey, glomospira cf. glomerosa eicher (fig. 4i); pseudonummoloculina sp. (fig. 4j); arenobulimina sp., vercorsella scarsellai (de castro); trocholina sp.; montsalevia salevensis (charollais, bronnimann & zaninetti) (fig. 4k); vercorsella wintereri arnaudvanneau & sliter (fig. 4l); and the green algae (dasycladales) salpingoporella annulata carozzi (figs. 4m, n) and salpingoporella sp. (figs. 4o, p). this assemblage indicates a probable early hauterivian age for these strata. the sedimentological characteristics of the strata and the presence of footprints indicate a short period of subaerial exposure of the sediment and suggest an intertidal depositional setting. according to biostratigraphic zonation and subdivision of the lower cretaceous (velić, 2007), which can be used platform-wide, the microfossil assemblage of the palud section can be assigned to the ver­ corsella camposaurii taxon-range zone (sartoni & crescenti, 1962). a more accurate age for the palud succession could be better determined with reference to the underlying strata in which the green alga pseudoclypeina? ne­ ocomensis (radoičić, 1975) was seen (work in progress) geologia croatica 68/2geologia croatica 116 figure 3: a stratigraphic column of the section exposed at palud cove. mezga et al.: dinosaur footprints in the lower hauterivian deposits of palud cove in istria, croatia geologia croatica 117 figure 4: the microfacies and microfossil assemblage of the section exposed at palud cove. a peloidal packstones/grainstones with different sections of salpingoporella annulata (guj 1a). b fenestral mudstones to wackestones (guj 1). c fenestral mudstone with geopetal infill (guj ab). d, e istriloculina cf. elliptica; transverse (d) and longitudinal (e) section (guj 1b, guj iv). f, g praechrysalidina cf. infracretacea; approximately longitudinal (f) and transverse (g) section (guj 4). h rumanoloculina cf. robusta; subtransverse section (guj 1a). i glomospira cf. glomerosa; oblique section (guj 3). j pseudonummoloculina sp.; oblique section (guj 2). k montsalevia salevensis; longitudinal section (guj iv). l vercorsella wintereri; longitudinal section (guj 10). m, n salpingoporella annulata; transverse, oblique (m) and longitudinal section (n). o, p salpingoporella sp.; oblique (o) and longitudinal section (p). geologia croatica 68/2geologia croatica 118 figure 5: the southeastern part of the palud site with the main footprint concentration. northwest (fig. 2). the observed stratigraphic relationships indicate that all footprints belong to the same horizon located along the upper bedding surface of a single layer. they are true footprints and most of them have a clearly defined expulsion rim, which allows their unmistakable identification as footprints despite substantial weathering and erosion of the outcrop. the pronounced height of the expulsion rim indicates that the substrate on which the trackmakers were walking was very soft. all footprints are of approximately the same shape and size, suggesting that they were all made by the same type of animal. the morphology of the footprints is very poorly defined in this karstified outcrop, which does not allow their referral to an ichnotaxon. the length of the footprints was measured from the anterior to the posterior part of the print along its axis and the that corresponds to the pseudoclypeina? neocomensis to campanellula capuensis unfossiliferous interval (early hauterivian) recognized on mljet island (husinec & sokač, 2006). 4. footprint description the palud site is located along the coast within the intertidal zone and is repeatedly flooded. this affected the preservation of the footprints and complicates their study. sixteen large footprints of circular to elliptical shape, with an average length of 26 cm, without clearly identifiable digit impressions, and with a rather indistinct morphology have been discovered at this site (figs. 5, 6; tab. 1). fifteen footprints are close to each other while a single track is several tens of metres away to the figure 6: a map showing the distribution of footprints 1-15 at the palud site. mezga et al.: dinosaur footprints in the lower hauterivian deposits of palud cove in istria, croatia geologia croatica 119 width was measured as a maximum width perpendicular to the length. on the prints with pronounced expulsion rims, the measures were taken only on the inner part of the prints (excluding the expulsion rims). on the prints without the expulsion rims, the measures were taken from the beginning of the depression margin. the best preserved footprint (no.12) represents an exception (figs. 7, 8). like most other tracks, it has a circular shape (length = 30 cm; width = 29.5 cm) and a well-defined and continuous expulsion rim that is up to 2 cm high. along its w-e axis there is a continuous fissure caused by rock fracture. what distinguishes this footprint from the others is the presence of four v-shaped, pointed grooves along its northeastern part that resemble digit impressions (fig. 7). these grooves are wider proximally and taper distally; this gives them an acutely pointed appearance. it is possible that these features do not actually represent digit impressions but were instead produced by selective corrosion that altered and modified the primary footprint.the running waters flowing into the footprint along the fractures could have been the cause for their formation where the erosion enlarged the fractures. similar features have already been recorded in sauropod footprints exposed to tidal weathering in the fenoliga islet (mezga & bajraktarević, 1999: fig. 2d; dalla vecchia et al., 2001: fig. 18). it is interesting that only footprint 12 has such large pointed grooves as footprints 1 to 10 have expulsion rims of figure 8: interpretative sketches of footprints 1 (a) and 12 (b). scale bar = 10 cm. figure 7: dinosaur footprint at the palud cove locality (no. 12 on fig. 5). scale bar = 22 cm. table 1: footprint measurement (all measurements in cm; fl = footprint length; fw = footprint width) footprint no. expulsion rim fl fw 1 + 29.5 28.5 2 – 32.5 31 3 + 31.5 32 4 + 28 31 5 + 29 31.5 6 + 23.5 27 7 + 21 26 8 + – – 9 + – – 10 + 31 31.5 11 – – – 12 + 30 29.5 13 – 27 27.5 14 + 18 19 15 + 15.5 15 16 + 24 20 geologia croatica 68/2geologia croatica 120 similar height and shape, suggesting that they were impressed at approximately the same time. this may support an erosional modification as an explanation for the unique morphology of footprint 12. the fact that there is no other footprint with such features could be explained by the selectivity of the erosion process. although isolated from the main group of footprints, footprint 16 is very similar in shape and size to the rest of the tracks (figs. 8, 9), which once again suggests it was produced by the same kind of trackmaker. footprints 1 to 7 are fairly eroded, but appear to be organized in two parallel lines indicative of a trackway trending 95°–275°. the prints cannot be interpreted as impressions of left or right feet with certainty and their interpretation as belonging to the same trackway is doubtful. along with the other footprints they could represent several parallel trackways of similarly sized animals. it is possible that footprints 8, 10 and 12 also form a trackway because they are aligned (fig. 10), but the trend is questionable. 5. discussion the poor preservation of the footprints makes the identification of the trackmaker difficult to establish. from their shape and orientation within the possible trackways, it is even uncertain whether they were produced by bipedal or quadrupedal animals. in fact, no clearly defined manus-pes pairs that would be indicative of a quadrupedal trackmaker can be identified in the sample. however, the circular shape of the palud footprints suggests that the author of the tracks was a quadrupedal animal because all early cretaceous potential bipedal trackmakers were theropod and ornithopod dinosaurs with three digits in the pes. crocodyliforms and turtles are potential trackmakers for quadrupedal tracks in an early cretaceous coastal setting; they can be plausibly excluded by the large size of the footprints (unless they were impressed by giant individuals of these groups). crocodyliforms can be also excluded because of their marked heteropody (the pes is much larger than the manus). among quadrupedal dinosaurs, potential trackmakers include the marginocephalia, thyreophora and sauropoda. quadrupedal marginocephalia (essentially the neoceratopsians) are not a likely candidate because the palud footprints are all similar in size without size differences between the prints of manus and pes (i.e. a lack of heteropody). furthermore, neoceratopsians are extremely rare in the cretaceous of europe and are not reported from the lower cretaceous (weishampel et al., 2004; ősi et al., 2010). the thyreophora include the basal tyreophorans, the stegosauria and the ankylosauria. stegosaur footprints have well defigure 10: the southeastern part of the palud site showing a possible trackway in the foreground. figure 9: isolated footprint no. 16 from the palud cove locality (scale bar = 22 cm). mezga et al.: dinosaur footprints in the lower hauterivian deposits of palud cove in istria, croatia geologia croatica 121 fined heteropody and their pes prints are tridactyl (thulborn, 1990). furthermore, stegosaur remains are uncommon in the lower cretaceous (weishampel et al., 2004). ankylosaurs do not have such pronounced heteropody as stegosaurs, and their pedal prints have impressions of four digits (thulborn, 1990), similar to the only palud footprint with possible digit impressions (fig. 7). the palud footprints, however, cannot be interpreted as made by ankylosaurians with certainty given their poor state of preservation and rather indistinct morphology. furthermore, ankylosaurian footprints are not reported in the palaeoichnological record of istria (see literature cited above). sauropods present heteropody, with the usually crescentic manus print that is always smaller than the oval to triangular pes print (thulborn, 1990; lockley et al., 1994). although the palud footprints do not match perfectly with the morphology of the footprints produced by the sauropods, it is possible that they belong to sauropod dinosaurs because such sauropod footprints were observed at the neighbouring and nearly coeval gustinja site (dalla vecchia et al., 2000). their referral to small sauropods is the most plausible conclusion considering that the footprints of those dinosaurs are relatively common in the cretaceous of istria (dalla vecchia, 2005) and so far most of the footprints with a subcircular outline in istria have been referred to this group.the upper hauterivian-lower barremian site of kolone (bale municipality) located just 2.5 km south of palud cove, yielded abundant skeletal remains of sauropod dinosaurs, but no ankylosaurians or stegosaurians (dalla vecchia, 1998). 6. conclusions the lower cretaceous carbonate succession of palud cove is characterized by shallow-water limestones deposited in peritidal environments (shallow subtidal to intertidal) with several shallowing–upward cycles. those cycles are composed of mudstones, peloidal wackestones/packstones, peloidal packstones/grainstones and fenestral mudstones to wackestones with geopetal infill. the microfossil assemblage, which is dominated by ostracods associated with foraminifera and green algae (dasycladales), suggests an early hauterivian age for this section. sixteen large circular-elliptical footprints lacking further morphological details have been observed on the upper bedding surface of a single layer of limestone. footprints are surrounded by a pronounced expulsion rim indicating that the substrate was waterlogged when the trackmakers walked on it. the footprints are of approximately the same shape and size, which is suggestive of the same kind of trackmaker for all of them. there are no clearly visible digit impressions and the average length is 26 cm. the most plausible trackmakers are small-sized sauropod dinosaurs. the track-bearing layer is fenestral mudstone with numerous geopetal infills; this together with the presence of footprints of a terrestrial animal, is evidence of short term exposure of the sediment to meteoric conditions and is indicative of an intertidal environment of deposition. acknowledgment this research was part of the science projects (nos. 119– 1191152–1169 and 119-1191152-1171) sponsored by the croatian ministry of science, education and sports. thanks to our colleagues goran mikša and bosiljka glumac for their help in the field and manuscript preparations. thanks to fabio marco dalla vecchia and ivo velić for the very useful comments and improvement of the manuscript. references dalla vecchia, f.m. (1994): jurassic and cretaceous sauropod evidence in the mesozoic carbonate platforms of southern alps and dinarids.– in: lockley, m.g., faria dos santos, v., meyer, c.a. & hunt, a. (eds): aspects of sauropod paleobiology, gaia, 10, 65–73. dalla vecchia, f.m. (1998): remains of sauropoda (reptilia, saurischia) in the lower cretaceous (upper hauterivian/lower barremian) limestones of sw istria (croatia).– geologia croatica, 51/2, 105–134. dalla vecchia, f.m. (2005): between gondwana and laurasia: cretaceous sauropods in an intraoceanic carbonate platform.– in: tidwell, v. & carpenter, k. (eds): thunder-lizards – the sauropodomorph dinosaurs. indiana university press, bloomington & indianapolis, 395–429. dalla vecchia, f.m. (2013): sulle tracce del passato – piste e impronte fossili di vertebrati in carnia e nelle aree contermini.– comunità montana della carnia, tolmezzo, 176 p. dalla vecchia, f.m., tarlao, a. & tunis, g. (1993): theropod (reptilia, dinosauria) footprints in the albian (lower cretaceous) of the quieto/mirna river mouth (nw istria, croatia) and dinosaur population of the istrian region during the cretaceous.– memorie di scienze geologiche, 45, 139–148. dalla vecchia, f.m. & tarlao, a. (2000): new dinosaur track sites in the albian (early cretaceous) of the istrian peninsula (croatia). part ii – paleontology.– in: dalla vecchia, f.m., tarlao, a., tunis, g. & venturini, s. (eds): new dinosaur track sites in the albian (early cretaceous) of the istrian peninsula (croatia). memorie di scienze geologiche, 52/2, 227–293. dalla vecchia, f.m., tarlao, a., tentor, m., tunis, g. & venturini, s. (2000): first record of hauterivian dinosaur footprints in southern istria (croatia).– in: vlahović, i. & biondić, r. (eds): proceedings, second croatian geological congress, cavtat-dubrovnik, 2000, 143–149. dalla vecchia, f.m., tarlao, a., tunis, g. & venturini, s. (2001): dinosaur track sites in the upper cenomanian (late cretaceous) of the istrian peninsula (croatia).– bolletino della societa paleontologica italiana, 40/1, 25–54. dalla vecchia, f.m., vlahović, i., posocco, l., tarlao, a. & tentor, m. (2002): late barremian and late albian (early cretaceous) dinosaur track sites in the main brioni/brijun island (sw istria, croatia).– natura nascosta, 25, 1–36. gušić, i. & jelaska, v. (1993): upper cenomanian-lower turonian sea-level rise and its consequences on the adriatic-dinaric carbonate platform.– geologische rundschau, 82, 678–686. husinec, a.& sokač, b. (2006): early cretaceous benthic associations (foraminifera and calcareous algae) of a shallow tropical-water platform environment (mljet island, southern croatia).– cretaceous research, 27, 418–441. lockley, m.g., farlow, j.o. & meyer, c.a. (1994): bronto­ podus and parabrontopodus ichnogen. nov. and the significance of wide-and narrow-gauge sauropod trackways.– in: lockley, m.g., faria dos santos, v., meyer, c.a. & hunt, a. (eds): aspects of sauropod paleobiology, gaia, 10, 135–145. geologia croatica 68/2geologia croatica 122 matičec, d., vlahović, i., velić, i. & tišljar, j. (1996): eocene limestones overlying lower cretaceous deposits of western istria (croatia): did some parts of present istria form land during the cretaceous? – geologia croatica, 49/1, 117–127. mezga, a. & bajraktarević, z. (1999): cenomanian dinosaur tracks on the islet of fenoliga in southern istria, croatia.– cretaceous research, 20, 735–746. mezga, a. & bajraktarević, z. (2004): cretaceous dinosaur and turtle tracks on the island of veli brijun, istria, croatia.– geologica carpathica, 55/5, 355–370. mezga, a., tunis, g., moro, a., tarlao, a., ćosović, v. & bucković, d. (2006): a new dinosaur tracksite in the cenomanian of istria, croatia.– rivista italiana di paleontologia e stratigrafia, 112/3, 435–445. mezga, a., cvetko tešović, b. & bajraktarević, z. (2007a): dinosaur tracks as an indicator of peritidal environment: an example from late hauterivian of palud bay, croatia.– in: zelilidis, a. (ed.): abstract book, 25th ias meeting of sedimentology, patras 2007, p. 276. mezga, a., cvetko tešović, b. & bajraktarević, z. (2007b): first record of dinosaurs in the late jurassic of the adriatic-dinaridic carbonate platform (croatia).– palaios, 22/2, 188–199. mezga, a., cvetko tešović, b., bajraktarević, z. & bucković, d. (2007c): a new dinosaur tracksite in the albian of istria, croatia.– rivista italiana di paleontologia e stratigrafia, 113/1, 139–148. ősi, a., butler, r.j. & weishampel, d.b. (2010): a late cretaceous ceratopsian dinosaur from europe with asian affinities.– nature, 465, 466–468. polšak, a. & šikić, d. (1973): osnovna geološka karta sfrj 1:100000, tumač za list rovinj k33-100 [basic geological map of sfry 1:100000, geology of the rovinj sheet – in croatian].– geološki zavod zagreb, savezni geološki zavod beograd, 51 p. sartoni, s. & crescenti, u. (1962): ricerche biostratigraphische nell mezozoico dell’appennino meridionale.– giornale di geologia, 29, 161–304. thulborn, r. a. (1990): dinosaur tracks.– chapman and hall, london, 410 p. tišljar, j., vlahović, i., velić, i., matičec, d. & robson, j. (1998): carbonate facies evolution from the late albian to middle cenomanian in southern istria (croatia): influence of synsedimentary tectonics and extensive organic carbonate production.– facies, 38, 137–152. velić, i. (2007): stratigraphy and palaeobiography of mesozoic benthic foraminifera of the karst dinarides (se europe).– geologia croatica, 60, 1–113. velić, i., tišljar j., vlahović, i., matičec, d. & bergant, s. (2003): evolution of the istrian part of the adriatic carbonate platform from the middle jurassic to the santonian and formation of the flysch basin during the eocene: main events and regional comparison.– in: vlahović, i. & tišljar j. (eds.): evolution of depositional environments from the palaezoic to the quaternary in the karst dinarides and the pannonian basin. field trip guidebook 22nd ias meeting of sedimentology, opatija, 2003, 3–17. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeography, palaeoclimatology, palaeoecology, 220/3, 333–360. weishampel, d.b., barrett, p.m., coria, r.a., leloeuff, j., xing, x., xijin, z., sahni, a., gomani, e.m.p. & noto, c.r. (2004): dinosaurian distribution.– in: weishampel, d.b., dodson, p. & osmolska, h. (eds.): the dinosauria. university of california press, berkeley, 517–606. manuscript received march 11, 2015 revised manuscript accepted may 26, 2015 available online june 16, 2015 http://bib.irb.hr/prikazi-rad?&rad=304975 http://bib.irb.hr/prikazi-rad?&rad=304975 www.geologia-croatica.hr abstract characterization of various fluid parameters in magmatic-hydrothermal ore mineralizations is potentially essential for interpretation of the conditions of formation and therefore for mineral exploration. fluid inclusions can provide a useful and promising tool in the research of the ore forming processes in these systems. this review focuses on the nature, composition and origin of magmatic-hydrothermal ore forming fluids involved in the formation of representative tertiary ore deposits at the rhodope metallogenic province in ne greece. these deposits are spatially related to tertiary magmatism in ne greece. case studies are presented here and include an intrusion-hosted sheeted vein system (kavala), a au-rich carbonate replacement and quartz-vein mineralization (asimotrypes), mineralized veins in eptadendro-rachi and thasos island (kapsalina and panagia), porphyry cu-more-au deposits in pagoni rachi and maronia and epithermal au-ag mineralizations in perama and loutros. hydrothermal fluids rich in co2 together with elevated au and te content are common and occur at the kavala intrusion hosted sheeted vein system, at the asimotrypes au-rich carbonate replacement mineralization and at the panagia (thasos) vein system. we classify all these ore mineralizations as intrusion-related gold systems (irgs). transport and precipitation of metals including au and te is favoured when co2 is present. precipitation of the ore mineralization takes place due to the immiscibility of the carbonic and the aqueous fluids which have a magmatic origin with the contribution of meteoric water. cooling of magmatic hydrothermal fluids and dilution with meteoric water is a common cause for ore mineral formation in the vein mineralizations of eptadendro/ rachi and kapsalina thasos. at the pagoni rachi and maronia porphyry deposits, boiling and the high proportion of the vapour phase are the most essential fluid processes which affected ore formation. the epithermal veins overprinting the pagoni rachi and the maronia porphyry systems and the hs-is epithermal system in perama hill and the is epithermal mineralization in loutros are characterized by low to moderate temperatures and low to moderate salinities. cooling and dilution of the ore fluids are the main process for gold precipitation. we conclude that the different fluid parameters and microthermometric data indicate a variety of fluid origin conditions and sources which can affect the strategy for exploration and prospecting for gold, rare and critical metals. keywords: fluid inclusions, metallogeny, rhodope, intrusion related systems, porphyry systems, epithermal mineralizations article history: received december 02, 2015 revised and accepted january 01, 2016 avaliable online february 29, 2016 1. introduction large-scale magmatic-hydrothermal fluid circulation in the earth’s crust is derived from intermediate to felsic hydrous magmas mainly at convergent plate margins, providing endogenic heat and mass transfer for the formation of ore deposits including base, precious and rare metals (lehmann et al., 2000; blundell et al., 2005; simmons & brown, 2006; bortnikov, 2006; heinrich, 2007). these systems involve large amounts of volatiles including magmatic, meteoric or metamorphic water in aqueous or vapour form, co2, nacl, kcl, cacl2, mgcl2, h2s, ±ch4, ±n2, as well as metals which originate from the magmas or the leaching processes from the rocks penetrated by the fluids through fluidwall-rock interactions. the detection of the various fluid characteristics is potentially important for interpretation of the formation of numerous ore deposit types and consequently for mineral exploration (baker & lang, 2001; wilkinson, 2001; heinrich, 2005; chang et al., 2011; kesler et al., 2013). for example boiling has been a valuable guide in gold and copper exploration in porphyry systems. it is useful therefore to know how the volatile phases originate, how they dissolve and transport metals, which is the role of temperature and pressure and under what conditions the metallic minerals are deposited. a useful fluid parameter which can be achieved by the fluid inclusions study, especially in the systems associated with au and other sidirophile elements enrichment, is the co2 content, because there is a strong correlation between co2 content and gold mineralization, such as in the deepseated intrusion-related systems (lowenstern, 2001; baker 2002). in general, fluid inclusions with elevated homogenization temperatures and high salinities indicate magmatic productive fluids, while fluid inclusions with low ho157-167 3 figs. 1 tab. doi: 10.4154/gc.2016.12 fluid evolution in tertiary magmatic-hydrothermal ore systems at the rhodope metallogenic province, ne greece. a review. vasilios melfos1,* and panagiotis voudouris2 1 aristotle university of thessaloniki, department of mineralogy, petrology and economic geology, thessaloniki, 54124, greece (*corresponding author, email: melfosv@geo.auth.gr) 2 university of athens, department of mineralogy-petrology, athens 15784, greece 158 vol. 69/1 mogenization temperature and low salinity show incorporation of meteoric waters (wilkinson, 2001; kesler et al., 2013). it is evident that homogenization temperatures, fluid salinity, density and pressure, can be useful in the determination of the fluid sources, the physical and chemical processes of transport and deposition of metals and also to explain the chemical environments of ore deposition and the possible zonation patterns of some ore systems. this review paper summarizes the nature, composition and origin of magmatic-hydrothermal ore forming fluids which were involved in the formation of representative tertiary ore deposits at the rhodope metallogenic province in ne greece (fig. 1) which are developed within or around magmatic intrusive or extrusive rocks. we explore the evolution of high temperature and high salinity magmatic brines or co2-rich fluids, as well high temperature and low salinity magmatic vapours, to low temperature and low salinity meteoric fluids which were involved in the formation of these ore mineralizations. this paper is partly motivated by microthermometric measurements of fluid inclusions which have been published in previous works of several researchers (vavelidis et al., 1995; eliopoulos, 2000; melfos et al., 2002; vavelidis & melfos, 2004; melfos et al., 2008, 2010; fornadel et al., 2011; eliopoulos & kilias, 2011; voudouris et al., 2011, 2013b) and include a reduced intrusionrelated system (kavala), a au-rich carbonate replacement mineralization (asimotrypes), mineralized veins in eptadendro-rachi and thasos island (kapsalina and panagia), porphyry cu±au±mo deposits in pagoni rachi and maronia and epithermal mineralizations in perama and loutros (fig. 1). the purpose of this work is to show that detailed exploration for the discovery of new ore deposits requires a thorough fluid inclusion study which will interpret fluid phase relations and evaluate fluid characteristics in view of the ore forming conditions. 2. geological setting of tertiary ore deposits greece is traditionally a mining country with numerous ore deposits which include base (cr, ni, mn, al, fe, pb, zn, cu), precious (au, ag, platinum group elements-pge), rare (bi, te, mo, re, ti) & critical (mg, sb, w, co, ga, ge, in, ree) metals (melfos & voudouris, 2012). mining dates back to prehistoric times focusing initially on gold, copper and iron mineralizations. later, in the classical and hellenistic times, ore exploitation became more intense especially for au, ag, cu and fe. famous ancient mining centres operated in milos and sifnos islands (aegean sea), in lavrion (attica), in chalkidiki, palea kavala, pangeon mt and thasos island (n. greece), where a great number of underground galleries and metallurgical furnaces are still preserved (pernicka et al., 1981; georgakopoulou et al., 2011). several metals, such as ag, au, fe, cu, were also produced during the byzantine and ottoman periods (nerantzis, 2009). since the beginning of the 20th century a great number of ore deposits have been targeted for exploration and exploitation of cr, ni, al, mn, fe, pb, zn, cu, au and ag. greece is the most important producing country in the eu for ni-fe (from laterites) and al figure 1. simplified geological map of the rhodope metallogenic province, ne greece, showing the studied mineralizations. kavala (kv) intrusion-related system, asimotrypes (as) au-rich carbonate replacement mineralization, eptadendro-rachi (er) mineralized veins, kapsalina (kp) and panagia (pn) cu-bi-ag±te vein systems in thasos island, pagoni rachi (pr) and maronia (mr) cu-mo-re-au porphyry deposits, perama hill (ph) and loutros (lt) epithermal mineralizations. 159 melfos & voudouris: fluid evolution in tertiary magmatic-hydrothermal ore systems at the rhodope metallogenic province... (from bauxites). the production of mg from magnesite is also significant (tsirambides & filippidis, 2012). the geological setting of the hellenides, part of the alpinehimalayan orogeny, comprises numerous geotectonic terrains, which resulted as a consequence of the complicated geodynamic events in the region of the palaeotethys and neotethys oceans, including ocean rifting, spreading, subduction, collision, post-collision and extensive subduction and post-subduction magmatism (pe-piper & piper, 2002). after closure of the neotethys ocean, syn-orogenic exhumation of hp-lt rocks occurred during the late cretaceous-eocene, before an acceleration of slab retreat changed the subduction regime and caused collapse of the hellenic mountain belt and thinning of the aegean sea from oligocene to the present (jolivet & brun, 2010). during this post-orogenic episode large scale detachments formed which exhumed metamorphic core complexes in a back-arc setting. tertiary to quaternary calc-alkaline to alkaline magmatism in the aegean region occurred mostly in a post-collisional setting behind the active hellenic subduction zone (pe-piper & piper, 2001). lithospheric delamination, roll-back and/or break-off of the subducting slab were the principal mechanisms resulting in magma generation, which was triggered by asthenospheric mantle upwelling (jolivet & brun, 2010). in this geotectonic regime, large ore deposits of economic importance were formed during the tertiary, in relation to magmatism and the evolution of extensive magmatic-hydrothermal systems. the ore types include reduced intrusion-related, skarn, porphyry, high-, intermediateand low-sulfidation epithermal, carbonate-hosted replacement pb-zn and polymetallic vein deposits (melfos et al., 2002; voudouris & alfieris, 2005; voudouris, 2006; bonsall et al., 2011; melfos & voudouris, 2012; voudouris et al., 2013a). they are concentrated into four regional metallogenic regions: 1) the rhodope metallogenic province (rmp), 2) the serbomacedonian metallogenic province (smmp), 3) the atticocycladic metallogenic province (acmp) and 4) the eastern aegean metallogenic province (eamp). these regions are the most promising targets for the near future exploration and exploitation of precious, rare and critical metals in greece. tertiary basins and magmatic settings in the rhodope massif are associated with significant skarn, polymetallic vein, porphyry and epithermal ore deposits, which are occasionally rich in au and critical metals (melfos et al., 2002; voudouris, 2006; voudouris et al., 2009, 2011, 2013b), which constitute a part of the rhodope metallogenic province. the magmatic-hydrothermal deposits of the rhodope metallogenic province were formed during the final stage of the tertiary orogenic collapse, and are related to the emplacement of hot asthenosphere into shallow crustal levels above a detached lithospheric plate which generated widespread magmatism (de boorder et al., 1998; blundell et al., 2005). the oligocene-miocene magmas were intruded to shallow depths along deep seated detachment faults, forming mafic to felsic mantle-derived plutonic, subvolcanic and volcanic rocks of calc-alkaline, high-k calc-alkaline and shoshonitic to ultrapotassic (lamprophyric) affinities (christofides, 1996; marchev et al., 2005). 3. fluid inclusion case studies 3.1. kavala intrusion-related gold system the kavala intrusion-related gold system (irgs) is part of the palea kavala ore system (fig. 1) which includes ~150 ore mine ralizations occurring either as primary hypogene quartzcalcite-sulfide veins or as supergene oxidized ore bodies, associated with the ~21–22 ma granodioritic kavala pluton of itype (fornadel et al., 2011). this pluton intruded marbles, schists, amphibolites and gneisses of the palaeozoic rhodope metamorphic core complex, along the regional e–w trending kavala-xanthi-komotini fault (fig. 1). the mineralization is considered to be part of an intrusion-related ore system in overlapping zones centred on the pluton. the marble hosts distal oxidized fe-mn (pb±zn±ag) and fe-mn-au ore bodies, whereas the gneiss and pluton contain proximal fe-cu-au, feas-au and bi-te-au vein mineralization. these ore mineralizations were exploited in ancient times for gold and silver with extensive underground and surface mining operations (vavelidis et al., 1996). figure 2. fluid inclusion types from tertiary ore mineralizations in the rhodope metallogenic province, ne greece. a. type l two phase aqueous liquid-vapour fluid inclusion coexisting with type c three phase inclusion which contain h2o-co2, in kavala sheeted vein system in the pluton; b. type l two phase, liquid and vapour, fluid inclusion in a quartz vein at eptadendro/rachi; c. type v vapour-rich two-phase aqueous inclusion coexisting with type l-s inclusion which contain three phases: a liquid, a vapour and a halite crystal in pagoni rachi porphyry system, indicating that they originate from a deep near-critical single phase fluid by phase separation; d. type v two-phase vapourrich inclusion with an opaque daughter crystal possibly chalcopyrite in pagoni rachi porphyry system; e. type v vapour-rich two-phase aqueous inclusion coexisting with type l-s inclusion which contain three phases: a liquid, a vapour and a halite crystal, and type l two phase aqueous liquid-vapour fluid inclusion in maronia porphyry system; f. type l aqueous liquid rich fluid inclusions which contain mainly nacl in quartz at perama hill epithermal deposit. 160 vol. 69/1 the se-nw trending bi-te±pb±sb±au quartz sheeted veins crosscut the pluton and the neighbouring metamorphic rocks in the chalkero area, and contain pyrite, tetradymite, bismuthinite, cosalite and sb-lillianite (fornadel et al., 2011). the veins consist of quartz, k-feldspar, albite and muscovite, altered to sericite and kaolinite. fluid inclusions in these veins (tab. 1) are rounded in shape, consistently distributed throughout the samples with a length of up to 60 μm (with the majo rity in the 25 to 35 μm range). they are classified into three types which coexist in each sample (melfos et al., 2008; fornadel et al., 2011) and therefore belong to the same primary fluid inclusion assemblage based on the criteria of goldstein & reynolds (1994). type l contains two phase aqueous liquid-vapour fluid inclusions (fig. 2a) with nacl and cacl2 and 20-30 volume % vapour. homogenization temperatures range between 216° and 420°c, with a maximum at 380°c, and the salinities vary from 15.9 to 22.6 wt% nacl equiv. type c inclusions (fig. 2a) are three phase: aqueous liquid, co2-liquid, co2-vapour approximately 50-70 volume %, with minor ch4. they homogenize at 255°-414°c, with a peak at 320°c, demonstrating salinities from 5.5 to 11.2 wt% nacl equiv. the third type v consists of two phase aqueous vapour-liquid fluid inclusions with a bubble of 90-95%, which homogenized to the vapour phase at th between 210° and 323°c (max= 280°c). the three fluid inclusion types are considered to represent coexisting immiscible carbonic and aqueous ore forming fluids (fig. 3a). isochores for fluid inclusions within the kavala veins revealed a depth of formation, between 3 and 5 km (melfos et al., 2008; fornadel et al., 2011). carbon dioxide played a significant role in the ore mineral precipitation in the kavala veins. 3.2. asimotrypes carbonatereplacement and vein type au deposit at pangeon mountain the pangeon mountain includes numerous carbonate replacement, vein and shear-hosted au-ag ore mineralizations, which were mined intensively during ancient times for gold and silver (vaxevanopoulos et al., in press). they are hosted in the marbles and gneisses of the rhodope massif as well as in the pangeon granitoids. one of the most important ore mineralizations occurs in asimotrypes (fig. 1) which is hosted in the nikisiani pluton, part of the pangeon granitoids, and in the marbles of the rhodope massif (eliopoulos, 2000; eliopoulos & kilfigure 3. homogenization temperatures versus salinity plots of fluid inclusions from various tertiary ore mineralizations in the the rhodope metallogenic province, ne greece. a. kavala intrusion related sheeted quartz veins (n=241); b. eptadendro/rachi mineralized quartz veins (n=249); c. pagoni rachi porphyry system overprinted by epithermal veins (n=362); d. maronia porphyry system overprinted by epithermal veins (n=90); e. perama hill hs-is epithermal system (n=141); f. loutros is epithermal system (n=36). n=number of measurements. 161 melfos & voudouris: fluid evolution in tertiary magmatic-hydrothermal ore systems at the rhodope metallogenic province... ias, 2011; vaxevanopoulos et al., in press). the pangeon granitoids consist of tonalite, granodiorite and granite. they demonstrate characteristics of high-k calc-alkaline metaluminous to slightly peraluminous post-collisional rocks and have a hornblende 40ar/39ar age of 21 to 22 ma (eleftheriadis & koroneos, 2003). the mineralization is associated with structurally controlled quartz veins, pods and lenses, and in gold-bearing replacement bodies, and is partly oxidized. it consists mainly of pyrite and arsenopyrite, with minor galena, sphalerite, chalcopyrite, pyrrhotite, tetrahedrite-tennantite, marcasite and gold (eliopoulos, 2000; vaxevanopoulos et al., in press). fluid inclusions are irregular to euhedral in shape with smooth boundaries reaching in size up to 20 μm. three types of primary fluid inclusions (tab. 1) were distinguished by eliopoulos (2000) and coexist in each sample being in equilibrium with the sulfide minerals. type l contains two phase aqueous liquid-vapour fluid inclusions with nacl. the bubble occupies 10-20 volume % and the homogenization temperatures range from 135° to 256°c with a peak at 190°c and salinities from 5.62 to 9.05 wt% nacl equiv. type c inclusions are three phase and contain liquid h2o-rich, liquid co2 and vapour co2 (70 to 90% by volume). they homogenize at temperatures between 275° and 340°c, with a maximum at 320°c, and show salinities from 2.61 to 7.31 wt% nacl equiv. the third type v consists of two phase aqueous vapour-liquid fluid inclusions which show decrepitation or leaking and no microthermometric measurements were achieved. the gold mineralization was formed by coexisting immiscible carbonic and aqueous fluids at pressures of 1.8 to 2.0 kbars under lithostatic conditions corresponding to depths of 6 to 9 km with the ore fluids at ~270°c (eliopoulos & kilias, 2011). 3.3. eptadendro-rachi vein type ag-au ore mineralization the cu-rich sulfide mineralization at the eptadendro-rachi ore district in thrace, ne greece, occurs at the contacts between granitoid intrusions (trodhjemites and pegmatites) of upper cretaceous to early tertiary age, and the meta-ultrabasic to basic rocks of the eastern rhodope massif (fig. 1). according to chatzikirkou & michailidis (2004) the ore bodies form quartz veins with pyrite, chalcopyrite, sphalerite, galena, hessite, bismuthinite, emplectite, tetradymite, aikinite, wittichenite, siegenite, millerite, bornite, pyrrhotite, covellite, magnetite, haematite and goethite. chlorite, calcite and sericite are the alteration minerals associated with the vein mineralization. fluid inclusions have negative crystal or rounded to elongated isometric shapes with a length up to 42 μm, and are distributed along crystal faces of quartz and therefore are suggested to have a primary origin (melfos et al., 2010). at room temperature they contain two phases, a liquid and a vapour phase which occupies 20-30 % by volume. two fluid inclusion assemblages (fias) were identified melfos et al. (2010). the first fia is hosted in quartz and is characterized by two phase, liquid and vapour, inclusions (type l, fig. 2b) at room temperature which homogenize to liquid at temperatures from 300° to 380°c, with a peak at 330°c, and exhibit low salinities, 1.6 to 7.2 wt% nacl equiv, corresponding to the fluids of the main ore stage. the second fia also include two phase fluid inclusions (type l) and are distinguished by a drop in th (210° to 260°c, with a peak at 240°c) corresponding to the late ore stage associated with calcite formation, whereas the salinities (3.2 to 6.3 wt% nacl equiv) are similar to the first fia. nacl is the dominant salt component of the fluids. the low to moderate salinities (1.6 to 7.2 wt% nacl equiv) of the two fias are possibly attributed to mixing between ascending magmatic fluids and downward migrating dilute meteoric water. according to melfos et al. (2010) such a process is very likely in a hydrothermal environment with a fault-controlled vein structure and causes ore deposition by diluted fluids at decreasing temperatures, from 380° to 210°c (fig. 3b). 3.4. thasos (kapsalina and panagia) vein type ore mineralizations thasos has been mined for au and ag both during antiquity, and in the 20th century (vavelidis et al., 1988). silver rich carbonate pb-zn replacement deposits occur at the western part of the island, whereas cu-au and gold deposits exist at the northeastern and eastern part of the island (vavelidis & amstutz, 1983). two cu-bi-ag±te mineralizations on thasos island, in kapsalina and panagia areas (fig. 1) have been described by vavelidis et al. (1995) and vavelidis & melfos (2004). the kapsalina copper mineralization is hosted in quartz veins which crosscut the schists of the rhodope massif. the ore mineralization consists mainly of chalcopyrite and pyrite, with minor bismuthinite, tetrahedrite-tennantite and gersdorffite (vavelidis & melfos, 2004). fluid inclusions were studied in quartz from the mineralized veins and were identified as primary and pseudosecondary. their size ranges from 4 to 45 μm, mainly up to 10 μm. based on their phase assemblages at room temperature one type of inclusion (type l) was distinguished containing a liquid aqueous solution and a vapour bubble (approximately 10 volume %). the fluid is dominated by nacl with a minor contribution of kcl demonstrating salinities from 1.0 to 3.3 wt% nacl equiv. homogenization temperatures of the fluid inclusions vary mainly from 120 to 280°c, with a peak at 200°c (vavelidis & melfos, 2004). the mineralization was formed by cooling of the hydrothermal fluids which were derived mainly by meteoric waters. the mineralization in panagia is hosted in quartz veins which crosscut the schists, marbles, dolomitic marbles, amphibolites and gneisses of the rhodope massif. the mineralization consists of chalcopyrite, pyrrhotite, pyrite, tetrahedrite-tennantite, gersdorffite, tetradymite and hessite. microthermometric measurements were carried out on fluid inclusions of the mineralized quartz (vavelidis et al., 1995). based on their phase proportions at room temperature, three types of fluid inclusions were distinguished which belong to the same primary fluid inclusion assemblage based on the criteria of goldstein & reynolds (1994). fluid inclusions of type l (up to 18 μm in length) consist of liquid rich two162 vol. 69/1 phase inclusions which contained mainly nacl and the vapour ranges from 10 to 20 % in volume. the homogenization temperatures vary between 229° and 305°c, with a maximum at 290°c and the salinities are low, from 3.12 to 3.28 wt% nacl equiv. the type c fluid inclusions, with a length up to 20 μm, contain three phases dominated by aqueous liquid, co2-liquid and co2-vapour approximately 60-70 % of the total volume. a total fluid salinity of 3.7 to 6.5 wt% nacl equiv was estimated. final homogenization temperatures of this type of inclusions vary from 313 and 360°c, with a maximum at 330°c. a third type of fluid inclusion is made up by large irregularly shaped cavities, which contain pure co2. the vein type mineralizations in panagia were formed by two coexisting immiscible carbonic and aqueous fluids and co2 played a significant role in the ore precipitation. 3.5. pagoni rachi porphyry cu-mo-re-au deposit the pagoni rachi cu-mo-re-au mineralization (fig. 1) belongs to the kirki mining district and is a telescoped porphyry-epithermal system which is spatially related to calc-alkaline granodiorite-tonalite porphyry stock of oligocene age (voudouris et al., 2013b). alteration types and vein relationships suggest that mineralization can be divided into four paragenetic stages, which are, from early to late: (1) sodic/ potassic-calcic alteration with quartzand magnetite-bearing veins (aand m-type) and distal propylitic alteration, (2) sodic/potassic alteration with quartz-pyrite-chalcopyrite-molybdenite veins (b-type), (3) sericitic alteration with “transitional” porphyry to epithermal pyrite-chalcopyrite-molybdenite veins (d-type), and (4) argillic alteration with quartzcalcite base metal and precious metal rich veins (e-type) with epithermal affinity. the mineralization contains molybdenite with up to 4.7 wt% re and the rare mineral rheniite (voudouris et al., 2009, 2013b). fluid inclusions were studied in the various vein types (a, b, and e) and are in equilibrium with the sulfide minerals and therefore represent the ore forming fluids (voudouris et al., 2013b). their maximum size is 30 μm (mainly between 7 and 15 μm). they are isolated or arranged along quartz and calcite growth zones and are considered to have a primary origin based on the criteria of bodnar (2003). three types of primary fluid inclusions were identified (voudouris et al., 2013b). type l consists of two-phase aqueous inclusions with a vapour bubble occupying 10 to 20 volume %, which homogenize to a liquid phase. type l-s inclusions contain three phases: a liquid, a vapour (10 to 20 volume %) and a halite crystal (fig. 2c). type v inclusions are two-phase vapour-rich (~80 volume %) aqueous inclusions (fig. 2c,d). they homogenize to the vapour phase. they commonly contain an accidental-trapped opaque crystal (fig. 2d) possibly chalcopyrite (voudouris et al., 2013b). three distinct primary fluid inclusion assemblages (fias) were identified (voudouris et al., 2009, 2013b). the first two assemblages contain coexisting l, l-s and v inclusion types in aand b-veins. the third assemblage includes late type l inclusions in the epithermal e-veins. aand b-veins were deposited at temperatures ranging between 360 and 510 °c and at pressures up to 690 bars (<2 km depth) for a-veins and up to 360 bars (<1.5 km depth) for b-veins, from boiling hydrothermal fluids. this process produced coexisting low to moderately saline (1.7-10.7 wt% nacl equiv) and highly saline (36->74 wt% nacl equiv) fluids (fig. 3c). the fluid inclusions in the aand b-type veins indicate that vapour was the predominant ore-forming fluid. subsequent dilution of the moderately saline fluid resulted in a lower temperature (210–340 °c), less saline (1.4–2.9 wt% nacl equiv) mineralizing fluid in late epithermal e-veins (fig. 3c, voudouris et al., 2013b). 3.6. maronia porphyry cu-mo-re-au minera lization the maronia cu-mo-re-au mineralization (fig. 1) is hosted by a porphyritic microgranite (melfos et al., 2002). three hydrothermal alteration zones have been recognized: an argillic, a sericitic and a propylitic zone. additionally, three highly silicified zones crop out at the microgranite. chalcopyrite-pyrite-molybdenite mineralization is located mainly in the silicified zones and is associated with areas of sericitic and propylitic alteration. the molybdenite revealed unusually high and variable rhenium concentrations (re from 0.12 to 4.21 wt%). fluid inclusions which were studied in the ore-related quartz (melfos et al., 2002) have rounded to elongated or negative-crystal shapes and are isolated or arranged along quartz demonstrating a primary origin. their size reaches up to 60 μm. four types of fluid inclusions were identified (melfos et al., 2002). type l contains 2-phase aqueous liquid-rich inclusions (vapour 20-35 volume %) and type l-s consists of 3-phases, an aqueous liquid phase, a vapour (2040 volume %) and a halite (nacl) crystal (fig. 2e). type v inclusions are two-phase vapour-rich (70-90 volume %), whereas type v-s are 3-phase aqueous vapour-rich (60-80 volume %) inclusions with a daughter mineral (halite). fluid inclusions, mainly types l and l-s contain an accidentallytrapped opaque phase (pyrite and/or chalcopyrite?), which suggests that they represent the mineralizing fluid at the maronia deposit. microthermometric results from the porphyry system showed that propylitic alteration and associated magnetitepyrite-quartz veins are characterized by temperatures between 320 to 410°c, with a mean at 400°c. trapping temperatures in the quartz-pyrite-chalcopyrite veins from sericitic alteration zone range from 360 to 420°c, with a peak at 380°c, and record the main temperature range of copper deposition under boiling conditions. pyrite-molybdenite veins in sericitic zone were formed at slightly lower temperatures, from 250 to 360°c, with a maximum at 340°c. the ore-bearing fluids were dominated by nacl, with salinities ranging from 7.0 to 16.4 wt% nacl equiv in type l inclusions, from 28 to 55 wt% nacl equiv in l-s fluid inclusions, from 5.5 to 14.0 wt% nacl equiv in type v inclusions and from 38 to 51 wt% nacl equiv in v-s inclusions (fig. 3d). trapping pressures of the ore-forming fluids were estimated to vary from 150 to 510 bar and boiling along with cooling of the fluids are 163 melfos & voudouris: fluid evolution in tertiary magmatic-hydrothermal ore systems at the rhodope metallogenic province... considered to be the main processes of ore formation (melfos et al., 2002). 3.7. perama hill hs-is epithermal au-ag deposit an epithermal mineralization rich in au, ag, te and se occurs in perama hill at the petrota graben, ne greece (fig. 1). the ore mineralization is hosted in andesitic rocks and the overlying conglomerates and sandstones and exhibits characteristics of a high sulfidation system which was followed by deposition of an intermediate sulfidation mineralization (voudouris et al., 2011). it forms a sulfide rich vein-type in the andesite and a au-rich stratabound oxidized type in the overlying sedimentary rocks. the ore mineral paragenesis includes a complex pb-zn-bi-se-te-sn-au-ag hypogene ore assemblage with native gold, native tellurium and electrum. fluid inclusions have negative-crystal or elongated isometric shapes with a maximum diameter of 30 μm, and were observed in quartz (fig. 2f) and barite from the high sulfidation veins in andesite at depths of 88 m and 97 m (voudouris et al., 2011). they are aqueous liquid rich (type l) with ~20 volume % vapour and contain mainly nacl. they are isolated or arranged along the quartz or barite growth zones and consequently are defined as primary. homogenization temperatures in quartz vary from 211 to 331°c, with a maximum at 240°c, and salinities from 0.7 to 4.9 wt% nacl equiv. in barite the inclusions display th values of 222 to 256°c, with a maximum at 240°c, overlapping those of quartz, and very low salinities, between 0.8 and 2.3 wt% nacl equiv. the mineralization was formed by cooling and dilution of the ore fluids which were possibly derived by condensation of magmatic vapour with limited mixing with meteoric water between a higher temperature (330°c) and a higher salinity (4.9 wt% nacl equiv) end-member and a lower temperature (210°c) dilute (0.7 wt% nacl equiv) component (fig. 3e, voudouris et al., 2011). 3.8. loutros hill is epithermal ag deposit the loutros area belongs at the feres-soufli-dadia volcanosedimentary basin. an intermediate sulfidation epithermal mineralization (fig. 1) is associated with a zeolite-altered rhyolitic lava dome which demonstrates an age of 19.5 ma (whole rock k/ar geochronology, christofides et al., 2004). the ore mineralization consists mainly of pyrite and marcasite and occurs either in the form of hydrothermal breccias or in nw-trending massive or barite bearing veins. rarely barite-galena veins with sphalerite and minor chalcopyrite crosscut the rhyolite. the mineralized barite veins are enriched in mo (up to ≤15.6 g/t), as (up to 1058 g/t) and ag (up to 31 g/t). fluid inclusions with irregular elongated shapes and a size up to 25 μm, were observed in barite and are represented by type l which contains an aqueous liquid rich phase (10-20 volume % vapour). microthermometric results revealed a homogenization temperature range mainly between 220° and 329°c, with a maximum at 310°c, and salinities from 8.65 to 16.14 wt% nacl equiv (unpublished data). the formation of the mineralization is attributed to cooling of an ore magmatic fluid, dominated by nacl, and a possible limited mixing with meteoric water at 330 to 220°c (fig. 3f). 4. discussion based on phase composition at room temperature, five types of fluid inclusions were identified in quartz, calcite and barite from magmatic-hydrothermal ore mineralizations in the rhodope metallogenic province in ne greece: (1) type l twophase fluid inclusions consisting of an aqueous (low-salinity) solution with a vapour bubble with nacl and sometimes minor cacl2; (2) type c three phase inclusions which contain h2oco2, sometimes with occasional ch4; (3) type v two phase aqueous vapour-liquid fluid inclusions; (4) type l-s multiphase phase inclusions which contain an aqueous solution, a vapour bubble and a halite crystal; (5) type v-s – three phase aqueous vapour-rich inclusions with a halite crystal. at the porphyry mineralizations l and l-s fluid inclusions contain a pyrite or chalcopyrite crystal which shows that they represent the mineralizing fluid (roedder, 1977; bortnikov, 2006). however not all types of fluid inclusions occur in all ore mineralizations, suggesting that they formed from fluids of different composition and under various conditions (table 1). fluid inclusions in the kavala reduced intrusion related sheeted vein system hosting a bi-te-pb-sb-au mineralization, display a range of fluid compositions (types l, c). inclusions with low to moderate salinities (5.5 to 11.2 wt% nacl equiv) co2-rich fluids are common and co-exist with moderate to high salinity fluids (salinities 15.9 to 22.6 wt% nacl equiv). methane is detectable in the co2-rich fluid inclusions. kavala veins are characterized as a deep seated system (~3 to 5 km) which was formed by two co-existing high temperature (th=300° and 400°c), moderate to high salinity, immiscible carbonic and aqueous fluids (fornadel et al., 2011). fluid inclusions from asimotrypes carbonate replacement mineralization at pangaion mountain demonstrate the co-existence of two immiscible fluids, a low to moderate (2.61 to 7.31 wt% nacl equiv) carbonic fluid and a moderate salinity (5.62 to 9.05 wt% nacl equiv) aqueous fluid. eliopoulos & kilias (2011) have shown that the main cause of ore precipitation should be attributed to unmixing of two fluids, a carbonic and an aqueous, at depths from 6 to 9 km at ~270°c. in the quartz veins at panagia of thasos the fluids are dominated by two immiscible fluids, an aqueous-carbonic and an aqueous fluid, which have low to moderate salinities (3.7 to 6.5 wt% eq. nacl) and trapping temperatures from 340° to 360°c at 500700 kbar (vavelidis et al., 1995). the presence of te and the elevated temperatures of the panagia vein system possibly show that it is located proximally to a magmatic rock, which however is not exposed on thasos island but can only be assumed. kavala, asimotrypes and panagia ore systems show many similarities regarding their fluid characteristics. according to the intrusion related model presented by hart (2005) the kavala sheeted veins in the pluton and the adjacent metamorphic rocks represent the most proximal system, whereas asimotrypes carbonate replacement mineralization occurs at some distance from the nikisiani pluton, being part of an intrusionrelated gold system (irgs). panagia vein mineralization at 164 vol. 69/1 ta bl e 1. t er tia ry o re m in er al iz at io ns o f t he r ho do pe m et al lo ge ni c pr ov in ce , n e g re ec e, a nd th ei r fl ui d in cl us io n ch ar ac te ris tic s (ty pe s, te m pe ra tu re s, sa lin iti es , c om po si tio n) . l : l iq ui d ric h aq ue ou s flu id in cl us io ns ; c : t hr ee p ha se fl ui d in cl us io ns w ith a n aq ue ou s l iq ui d, a c o 2-l iq ui d an d a c o 2-v ap ou r p ha se ; v : v ap ou r r ic h aq ue ou s fl ui d in cl us io ns ; l -s : l iq ui d ric h aq ue ou s fl ui d in cl us io ns w ith a da ug ht er so lid p ha se ; l -s : v ap ou r r ic h aq ue ou s fl ui d in cl us io ns w ith a d au gh te r s ol id p ha se . o re d is tr ic t m et al s o re st yl e h os t m in er al fi ty pe s t h° c (m ax ) sa lin ity w t% n ac l e qu iv fl ui d co m po si tio n o re fo rm at io n co nd iti on s r ef er en ce s k av al a pb , s b, b i, te , a u in tru si on -h os te d, sh ee te d ve in s q ua rtz l 21 6 4 20 (3 80 ) 15 .9 22 .6 n ac l a nd c ac l 2 c oe xi st in g im m is ci bl e ca rb on ic a nd a qu eou s fl ui ds a t a d ep th o f 3 -5 k m . c o 2 p la ye d a si gn ifi ca nt ro le in th e or e pr ec ip ita tio n m el fo s et a l. (2 00 8) ; f o r n a d el et a l. (2 01 1) c 25 541 4 (3 20 ) 5. 5 1 1. 2 h 2o -c o 2, m in or c h 4 v 21 032 3 (2 80 ) n ac l a nd c ac l 2 a si m ot ry pe s (p an ge on m ou nta in ) fe , a s, pb , z n, c u, s b, a u c ar bo na te re pl ac em en t s ty le , p ar t o f a n ir g s q ua rtz l 13 525 6( 19 0) 5. 62 9. 05 n ac l c oe xi st in g im m is ci bl e ca rb on ic a nd a qu eou s fl ui ds a t a d ep th o f 6 -9 k m a t ~ 27 0° c . c o 2 p la ye d a si gn ifi ca nt ro le in th e or e pr ec ip ita tio n el io po u lo s (2 00 0) ; e li o po u lo s & k il ia s (2 01 1) c 27 534 0 (3 20 ) 2. 61 7. 31 h 2o -c o 2 v d ec re pi ta tio n e pt ad en dr o/ r ac hi c u, f e, z n, p b, te , b i, c o, n i, a g ve in st yl e, e ar ly st ag e q ua rtz l 30 038 0 (3 30 ) 1. 6 7 .2 n ac l c oo lin g an d di lu tio n of fl ui ds w ith a m ag m at ic o rig in m ix ed w ith m et eo ric w at er m el fo s et a l. (2 01 0) ve in st yl e, la te st ag e c al ci te l 21 026 0 (2 40 ) 3. 2 6 .3 t ha so s ( k ap sa lin a) c u, f e, a s, sb , b i, n i, a g, a u ve in st yl e q ua rtz l 12 028 0 (2 00 ) 1. 0 3 .3 n ac l ( m ino r k c l) c oo lin g of h yd ro th er m al fl ui ds d om in at ed by m et eo ric w at er va v el id is & m el fo s (2 00 4) t ha so s ( pa na gi a) c u, f e, a s, sb , b i, n i, te , a g, a u ve in st yl e, p ar t o f an in tru si on re la te d sy st em q ua rtz l 22 930 5 (2 90 ) 3. 12 3. 28 n ac l c oe xi st in g im m is ci bl e ca rb on ic a nd a qu eou s fl ui ds . c o 2 p la ye d a si gn ifi ca nt ro le in th e or e pr ec ip ita tio n va v el id is e t a l. (1 99 5) c 31 336 0 (3 30 ) 3. 7 6 .5 h 2o -c o 2 pa go ni r ac hi c u, f e, m o, a s, sb , p b, z n, b i, r e, t e, a g, a u po rp hy ry c um o -r ea u st yl e (a , b v ei ns ) q ua rtz l a : 2 47 -5 14 (4 50 ) a : 2 .4 – 1 0. 7 n ac l a a nd b -ty pe p or ph yr y st yl e ve in s w er e de po si te d at a d ep th < 2 km fr om a b oi lin g hy dr ot he rm al fl ui d. s ub se qu en t d ilu tio n of th e m od er at el y sa lin e flu id re su lte d in th e fo rm at io n of a lo w er te m pe ra tu re a nd le ss sa lin e flu id in th e la te e pi th er m al e -v ei ns v o u d o u r is e t a l. (2 01 3) b : 2 10 -5 13 (3 90 ) b : 1 .7 – 9 .2 ls a : 2 04 -> 60 0 (3 70 ) a : 3 8. 9 > 74 n ac l b : 3 61 -> 60 0 (3 90 ) b : 3 6. 4 > 74 v a : 2 45 -5 22 (3 90 ) a : 4 .9 – 1 0. 4 n ac l b : 2 76 -4 94 (4 00 ) b : 4 .6 – 9 .2 ep ith er m al o ve rp rin tin g (e v ei ns ) q ua rtz l 20 637 7 (2 50 ) 1. 1 – 2. 9 n ac l c al ci te l 13 633 9 (2 54 ) 1. 4 2 .9 n ac l m ar on ia c u, f e, m o, a s, sb , p b, b i, r e, a u po rp hy ry c um o -r ea u st yl e q ua rtz l 20 058 0 (3 65 ) 7 – 16 n ac l b oi lin g an d co ol in g of th e flu id s m el fo s et a l. (2 00 2) ls 21 051 5 (3 31 ) 28 – 5 5 v 27 559 0 (3 93 ) 5 – 14 vs 30 745 5 (3 81 ) 38 51 pe ra m a h ill pb , z n, b i, se , h sis e pi th er m al st yl e q ua rtz l 21 133 1 (2 40 ) 0. 7 4 .9 n ac l c oo lin g an d di lu tio n of fl ui ds w ith a m ag m at ic o rig in m ix ed w ith m et eo ric w at er v o u d o u r is e t a l. (2 01 1) te , s n, a g, a u b ar ite l 22 225 6 (2 40 ) 0. 8 2 .3 n ac l l ou tr os h ill fe , p b, a s, a g is e pi th er m al st yl e b ar ite l 22 032 9 (3 10 ) 8. 65 16 .1 4 n ac l c oo lin g of a m ag m at ic o re fl ui d po ss ib ly m ix ed w ith m et eo ric w at er th is st ud y 165 melfos & voudouris: fluid evolution in tertiary magmatic-hydrothermal ore systems at the rhodope metallogenic province... thasos island also demonstrates features which are similar to an irgs, although there is no plutonic rock occurrence on the island. in these three systems aqueous-carbonic and aqueous fluids coexist in the same samples, demonstrating that carbon dioxide played a significant role in ore formation. it has been emphasized that co2 is the medium which can induce transport and precipitation of some metals, including gold, and aids the process of ore deposition by phase separation in magmatichydrothermal systems (lang & baker, 2001; baker, 2002). this process is common in many intrusion related gold systems and has been cited as direct evidence for a magmatic fluid source (baker & lang, 2001), although decarbonization reactions in wall-rock and dissolution of co2 from crustal hydrothermal fluids may be also encountered (lowenstern, 2001). vein type ore mineralizations in the rhodope metallogenic province are fault-controlled vein structures. they show similar formation conditions (temperatures-salinities), but relatively different fluid chemical compositions. in the eptadendrorachi vein system the mineralization was caused by mixing between ascending magmatic fluids and downward migrating dilute meteoric water during cooling at homogenization temperatures from 380° to 210°c. these fluids with low to moderate salinities (1.6-7.2 wt% nacl equiv) probably show an association with a granitoid body at depth, of tertiary age, which is not exposed at the surface. the mineralized veins in kapsalina of thasos island were formed under similar conditions by low to moderate temperatures and low density fluids (th=120280°c, salinities=1.0-3.3 wt% nacl equiv) also by cooling of the hydrothermal fluids which were derived mainly by meteoric waters (vavelidis & melfos, 2004). the porphyry cu-mo-re-au ore systems in pagoni rachi and maronia demonstrate the contribution of the vapour phase and the highly saline fluids under boiling conditions for ore mineral precipitation. boiling processes resulted in the generation of coexisting low to moderately saline and highly saline fluids at temperatures from 300 to 500°c and the formation of the different hydrothermal alteration and ore zones (melfos et al., 2002; voudouris et al., 2013b). vapour and brine dominance in both porphyry systems indicate that they originate from a deep near-critical single phase fluid by decompression and subsequent phase separation. in this case a low-density magmatic vapour phase is the principal agent for metal transportation, according to the model proposed by heinrich (2005), williams-jones & heinrich (2005), hurtig & williams-jones (2015). the released magmatic derived vapour rich fluids can transport high concentrations of metals mainly cu and au. rapid expansion of vapour at a shallow depth favours cu, fe, mo, re and au saturation and precipitation of the related ore minerals. williams-jones & heinrich (2005) emphasize the role of vapour volatile and precipitation of the bulk of cu, au and mo at temperatures between 320 and 425°c at a shallow depth of about 2 km. at this temperature in the presence of iron, so2 in the fluid phase is reduced to h2s and h2so4, which favours the precipitation of sulfides, especially pyrite, chalcopyrite, bornite and molybdenite, and increases gold solubility. the same process decreases drastically the fluid ph and causes the generation of an increasingly acidic fluid, which is associated with the related hydrothermal alteration minerals, mainly sericite and after mixing with groundwater, kaolinite (heinrich, 2005). the shallow epithermal veins in the pagoni rachi porphyry system and the epithermal overprinting identified in maronia (melfos et al., 2002; voudouris et al., 2013b) were formed under lower temperature conditions due to cooling and dilution of the ore fluids, which were evolved from initial high temperature and low salinity fluids towards cooler and very low salinity hydrothermal fluids. the perama hill hs-is and the loutros is epithermal mineralizations show similar temperature conditions (220-330°c) but slightly different salinities. in perama hill the salinities range between 0.7 to 4.9 wt% nacl equiv indicating condensation of a magmatic vapour in the hydrothermal fluid with limited mixing with a fluid that had a major meteoric water component. in loutros the salinities are higher (8.65 to 16.14 wt% nacl equiv) which show a significant magmatic contribution in the hydrothermal fluid with possibly a limited mixing with meteoric water. the epithermal mineralizations in perama hill and loutros were formed by cooling and dilution of the ore fluids. these fluids may represent late stage magmatic fluids that probably mixed with meteoric or seawater fluids at shallow levels. 5. conclusions fluid inclusion studies of tertiary magmatic-hydrothermal ore mineralizations in the rhodope metallogenic province, ne greece, focus mainly on the chemical composition of the ore forming fluids and the formation conditions of the mineralizations, the role of the magmatic and meteoric fluids and their possible interaction for the metallogenesis, the immiscibility and boiling processes and the role of co2 in ore precipitation. the different fluid characteristics and microthermometric data indicate a variety of fluid origin conditions and sources which can affect the strategy for exploration and prospecting of ore deposits. carbon dioxide rich hydrothermal fluids and au and te mineralization is common and occurs at the kavala intrusion hosted sheeted vein system, at the asimotrypes au-rich carbonate replacement mineralization and at the panagia (thasos) vein system. transport and precipitation of metals like au and te is favoured when co2 is present. precipitation of the ore mineralization takes place due to the immiscibility of the carbonic and the aqueous fluids resulting in their unmixing. these fluids have a magmatic origin with the contribution of meteoric water and are derived from deep seated systems. based on geological and mineralogical criteria and the fluid inclusion data, we classify all these three ore mineralizations in kavala, asimotrypes and panagia of thasos, as parts of irgs. cooling of magmatic hydrothermal fluids and dilution with meteoric water is a common cause of ore mineral formation in vein mineralizations (eptadendro/rachi, kapsalina thasos). boiling and the vapour phase predominance are the most important processes for metallogenesis in the porphyry deposits (pagoni rachi and maronia). these features are common in 166 vol. 69/1 porphyry systems and the mining industry should focus on them during early stage exploration work. the epithermal veins overprinting the pagoni rachi and the maronia porphyry systems and the hs-is epithermal system in perama hill and the is epithermal mineralization in loutros are characterized by low to moderate temperatures and low to moderate salinities. cooling and dilution of the ore fluids are the main processes for gold precipitation. following these criteria of the fluid characteristics, exploration for gold, rare and critical metals could have encouraging results to promote the mining industry in the future by using fluid inclusion techniques. acknowledgment the authors would like to thank the reviewer ladislav palinkaš and an anonymous reviewer for their helpful and constructive comments on the manuscript. ms alisa martek is especially thanked for her editorial handling of the paper. references baker, t. & lang, j.r. (2001): fluid inclusion characteristics of intrusionrelated gold mineralization, tombstone–tungsten magmatic belt, yukon territory, canada.– mineralium deposita, 36, 563–582. baker, t. (2002): emplacement depth and carbon dioxide-rich fluid inclusions in intrusion-related gold deposits.– economic geology, 97, 1111–1117. doi: 10.2113/97.5.1111 blundell, d., arndt, n., cobblod p.r. & heinrich, c. (2005): processes of tectonism, magmatism and mineralization: lessons from europe.– ore geology reviews, 27, 333–349. doi: 10.1016/j.oregeorev.2005.07.003 bodnar, r.j. (2003): introduction to fluid inclusions.– in: samson, i.m., anderson, a.j. & marshall, d.d. (eds.): fluid inclusions: analysis and interpretation. mineralogical association of canada short course, 32, 1–8. bonsall, t.a., spry, p.g., voudouris, p.c., tombros, s., seymour, k.s. & melfos, v. (2011): the geochemistry of carbonate-replacement pb-zn-ag mineralization in the lavrion district, attica, greece: fluid inclusion, stable isotope, and rare earth element studies.– economic geology, 106, 619–651. doi: 10.2113/eco ngeo.106.4.619 bortnikov, n.s. (2006): geochemistry and origin of the ore-forming fluids in hydrothermal-magmatic systems in tectonically active zones.– geology of ore deposits, 48, 1–22. doi: 10.1134/s1075701506010016 chang, z., hedenquist, j.w., white, n.c., cooke, d.r., roach, m., deyell, c.l. & cuison, a.l. (2011): exploration tools for linked porphyry and epithermal deposits: example from the mankayan intrusion-centered cu-au district, luzon, philippines.– economic geology, 106, 1365–1398. doi: 10.2113/eco ngeo.106.8.1365 chatzikirkou, a. & michailidis k. (2004): the eptadendro and rachi sulfide mineralization, eastern rhodope, greece.– bull. geol. soc. greece, 36, 397–405 (in greek with english abstract). christofides, g. (1996): tertiary magmatism in the greek rhodope massif, northern greece: granitic plutons.– in: knezevic, v. & krstic, b. (eds.): terranes of serbia: the formation of the geologic framework of serbia and the adjacent regions. university of belgrade, belgrade, 155–160. christofides, g., pecskay, z., eleftheriadis, g., soldatos, t. koroneos, a. (2004): the tertiary evros volcanic rocks (thrace, northeastern greece): petrology and k/ar geochronology.– geologica carpathica, 55, 397–410. de boorder, h., spakman, w., white, s.h. & wortel, m.j.r. (1998): late cenozoic mineralization, orogenic collapse and slab detachment in the european alpine belt.– earth and planetary science letters, 164, 569–575. doi: 10.1016/s0012-821x(98)00247-7 eleftheriadis, g. & koroneos, a. (2003): geochemistry and petrogenesis of post-collision pangeon granitoids in central macedonia, northern greece.– chemie der erde-geochemistry, 63, 364–389. doi: 10.1078/0009-2819-00024 eliopoulos, d.g. & kilias, s.p. (2011): marble-hosted submicroscopic gold mineralization at asimotrypes area, mount pangeon, southern rhodope core complex, greece.– economic geology, 106, 751–780. doi: 10.2113/econgeo.106.5.751 eliopoulos, d.g. (2000): geochemistry and origin of the asimotrypes carbonatehosted mesothermal gold deposit, pangeon mountain, n. greece.– unpublished phd thesis, university of southampton, uk, 244 p. fornadel, a.p., spry, p.g., melfos, v., vavelidis, m. & voudouris, p. (2011): is the palea kavala bi-te-pb-sb ± au district, northeastern greece, an intrusion-related system?– ore geology reviews, 39, 119–133. doi: 10.1016/j.oregeorev.2011.01.002 georgakopoulou, m., bassiakos, y. & philaniotou, o. (2011): seriphos surfaces: a study of copper slag heaps and copper sources in the context of early bronze age aegean metal production.– archaeometry, 53, 123–145. doi: 10.1111/j.1475-4754.2010.00529.x goldstein, r.h. & reynolds, t.j. (1994): systematics of fluid inclusions in diageneticminerals.– sepm short course 31, tulsa, 199 p. hart, c.j.r. (2005): classifying, distinguishing and exploring for intrusionrelated gold systems. the gangue, geological association of canada, mineral deposits division newsletter, 87, 1 and 4–9. heinrich, c.a. (2005): the physical and chemical evolution of low-salinity magmatic fluids at the porphyry to epithermal transition: a thermodynamic study.– mineralium deposita, 39, 864–889. doi: 10.1007/s00126004-0461-9 heinrich, c.a. (2007): fluid-fluid interactions in magmatic-hydrothermal ore formation.– reviews in mineralogy and geochemistry, 65, 363–387. doi: 10.2138/rmg.2007.65.11 hurtig, n.c. & williams-jones, a.e. (2015): porphyry-epithermal au-ag-mo ore formation by vapour-like fluids: new insights from geochemical modeling.– geology, g36685-1. jolivet, l. & brun, j.p. (2010): cenozoic geodynamic evolution of the aegean.– international journal of earth sciences, 99, 109–138. doi: 10.1007/s00531-008-0366-4 kesler, s.e., bodnar, r.j. & mernagh, t.p. (2013): role of fluid and melt inclusion studies in geologic research.– geofluids, 13, 398–404. doi: 10.1111/gfl.12055 lang, j.r. & baker, t. (2001): intrusion-related gold systems: the present level of understanding.– mineralium deposita, 36, 477–489. doi: 10.1007/ s001260100184 lehmann, b., dietrich, a. & wallianos, a. (2000): from rocks to ore.– international journal of earth sciences, 89, 284–294. doi: 10.1007/ s005310000085 lowenstern, j.b. (2001): carbon dioxide in magmas and implications for hydrothermal systems.– mineralium deposita, 36, 490–502. doi: 10.1007/s001260100185 marchev, p., kaiser-rohrmeier, m., heinrich, c., ovtcharova, m., von quadt, a. & raicheva, r. (2005): hydrothermal ore deposits related to post-orogenic extensional magmatism and core complex formation: the rhodope massif of bulgaria and greece.– ore geology reviews, 27, 53–89. doi: 10.1016/j.oregeorev.2005.07.027 melfos, v. & voudouris, p.c. (2012): geological, mineralogical and geochemical aspects for critical and rare metals in greece.– minerals, 2, 300–317. doi: 10.3390/min2040300 melfos, v., chatzikirkou, a., michailidis, k. & voudouris, p. (2010): fluids related to remobilization of mesozoic sulfide mineralization in the eptadendro-rachi region in eastern rhodope, thrace, greece.– in christofides et al. (eds.): proceedings of the xix congress of the carpathian-balkan geological association, thessaloniki. scientific annals of the school of geology a.u.th., 100, 343–350. melfos, v., vavelidis, m., christofides, g. & seidel, e. (2002): origin and evolution of the tertiary maronia porphyry copper-molybdenum deposit, thrace, greece.– mineralium deposita, 37, 648–668. doi: 10.1007/s00126-002-0277-4 melfos, v., voudouris, p., vavelidis, m. & spry, p. (2008): microthermometric results and formation conditions of a new intrusion-related bi-te-pb-sb±au deposit in the kavala pluton, greece.– in: proceedings of the xiii all-russian conference on thermobarogeochemistry in conjunction with iv apifis symposium, vol 2, 165–168. nerantzis, n. (2009): pillars of power: silver and steel of the ottoman empire.– mediterranean archaeology and archaeometry, 9, 71–85. pe-piper, g. & piper d.j. (2001): late cenozoic, post-collisional aegean igneous rocks: nd, pb and sr isotopic constraints on petrogenetic and tectonic models.– geological magazine, 138, 653–668. pe-piper, g. & piper, d.j. (2002): the igneous rocks of greece.– gebroder borntraeger, berlin, germany, 573 p. doi: 10.1017/ s0016756801005957 pernicka, e., gentner, w., wagner, g.a., vavelidis, m. & gale, n.h. (1981): ancient lead and silver production on thasos (greece).– revue d’archéométrie, 1, 227–237. doi: 10.3406/arsci.1981.1151 roedder, ε. (1977): fluid inclusions as tools in mineral exploration.– economic geology, 72, 503–525. 167 melfos & voudouris: fluid evolution in tertiary magmatic-hydrothermal ore systems at the rhodope metallogenic province... simmons, s.f. & brown, k.l. (2006): gold in magmatic hydrothermal solutions and the rapid formation of a giant ore deposit.– science, 314, 288–290. doi: 10.1126/science.1132866 tsirambides, a. & filippidis, a. (2012): exploration key to growing greek industry.– industrial minerals, 533, 44–47. vavelidis, m. & amstutz, g.c. (1983): new genetic investigations on the pb-zn deposits of thasos (greece).– in: schneider, h.j. (ed.): mineral deposits of the alpine epoch in europe, berlin: springer-verlag, 359–365. doi: 10.1007/978-3-642-68988-8_36 vavelidis, m. & melfos, v. (2004): bi-ag-bearing tetrahedrite-tennantite in the kapsalina copper mineralisation, thasos island, northern greece.– neues jahrbuch für mineralogie – abhandlungen (journal of mineralogy and geochemistry), 180, 149–169. doi: 10.1127/00777757/2004/0180-0149 vavelidis, m., gialoglou, g., melfos, v. & wagner, g.a. (1996): goldgrube in palaea kavala-griechenland: entdeckung von skaptehyle?– erzmetall, 49, 547–554. vavelidis, m., gialoglou, g., wagner, g.a. & pernicka, e. (1988): die bundmetallund eisen-mangan-lagerstätten von thasos.– anschnitt, 6, 40–58. vavelidis, m., schmidt-mumm, a. & melfos, v. (1995): microthermometric investigations in the bi-te-ag bearing cu-mineralization of panagia area, thasos island, greece.– boletin soc. espan. mineralogia, 18–1, 261–262. vaxevanopoulos, m., vavelidis, m., malamidou, d., melfos, v. & pavlidis, s. (in press): excavations in ancient mines and metallurgical sites on the pangaion mountain (asimotrypes, valtouda).– the archaeological work in macedonia and thrace (in press, in greek). voudouris, p. & alfieris, d. (2005): new porphyry cu±mo occurrences in the north-eastern aegean, greece: ore mineralogy and epithermal relationships.– in: mao, j. & bierlein, f.p. (eds.): mineral deposit research: meeting the global challenge, springer berlin heidelberg, 473–476. voudouris, p. (2006): comparative mineralogical study of tertiary te-rich epithermal and porphyry systems in northeastern greece.– mineralogy and petrology, 87, 241–275. voudouris, p., melfos, v., spry, p.g., bindi, l., moritz, r., ortelli, m. & kartal, t. (2013a): extremely re-rich molybdenite from porphyry cu-mo-au prospects in northeastern greece: mode of occurrence causes of enrichment, and implications for gold exploration.– minerals, 3, 165–191. doi: 10.3390/min3020165 voudouris, p., melfos, v., spry, p.g., kartal, t., schleicher, h., moritz, r. & ortelli, m. (2013b): the pagoni rachi/kirki cumo±re±au deposit, northern greece: mineralogical and fluid inclusion constrains on the evolution of a telescoped porphyry-epithermal system.– canadian mineralogist, 51, 411–442. voudouris, p., melfos, v., spry, p.g., moritz, r., papavassiliou, c. & falalakis, g. (2011): mineralogy and geochemical environment of formation of the perama hill high-sulfidation epithermal auag-te-se deposit, petrota graben, ne greece.– mineralogy and petrology, 103, 79–100. doi: 10.1007/s00710-011-0160-z voudouris, p.c., melfos, v., spry, p.g., bindi, l., kartal, t., arikas, k., moritz, r. & ortelli, m. (2009): rhenium-rich molybdenite and rheniite (res2) in the pagoni rachi-kirki mo-cu-te-agau deposit, northern greece: implications for the rhenium geochemistry of porphyry style cu-mo and mo mineralization.– canadian mineralogist, 47, 1013–1036. wilkinson, j.j. (2001): fluid inclusions in hydrothermal ore deposits.– lithos, 55, 229–272. doi: 10.1016/s0024-4937(00)00047-5 williams-jones, a.e. & heinrich, c.a. (2005): 100th anniversary special paper: vapour transport of metals and the formation of magmatichydrothermal ore deposits.– economic geology, 100, 1287–1312. doi: 10.2113/gsecongeo.100.7.1287 2016 | 69/2 | 177–185 | 10 figs. | 2 tabs. | www.geologia-croatica journal of the croatian geological survey and the croatian geological society 1. introduction brachiopods are common marine macrofossils in the late carboniferous sedimentary rocks of velebit mt. they have been collected since the beginning of the 19th century and stored in the croatian natural history museum. upper carboniferous (pennsylvanian) sedimentary rocks from velebit mt. crop out in an elongate belt, 40 km long and up palaeobiogeography of the late carboniferous brachiopoda from velebit mt. (croatia) mirko japundžić1 and jasenka sremac2 1 gruška 16, 10 000 zagreb, hrvatska; (mijapundzic@gmail.com) 2 university of zagreb, department of geology, division of geology and paleontology, horvatovac 102a, 10 000 zagreb, croatia; (corresponding author: jsremac@geol.pmf.hr) doi: 10.4154/gc.2016.23 abstract an abundant and diverse late carboniferous brachiopod fauna from velebit mt. (croatia) comprises 63 brachiopod taxa dominated by productida and spiriferida. the spiriferinida, athyridida, orthotethida and rhynchonellata are less common, while the orthida, dictyonellida and terebratulida occur in very small numbers. brachiopods are mostly preserved as casts and moulds in shales, limestones and sandstones. associated fusulinid foraminifera and calcareous algae indicate a kasimovian to gzhelian age for the brachiopod–bearing deposits. the global biogeographic distribution of brachiopod taxa indicates the probable seaways and brachiopod migration routes, along the euramerican shelves. to 6 km wide, representing the core of an anticline, with a nw– se strike (fig. 1). they exhibit a variety of ancient environments varying from shoreline forests and swamps, through coastal and shallow shelf biomes (sremac, 2012; cleal et al., 2015). carboniferous shelves were densely populated with foraminifera (mostly fusulinids), calcareous algae, brachiopods, crinoids, bryarticle history: manuscript received september 30, 2015 revised manuscript accepted june 21, 2016 available online june 29, 2016 keywords: brachiopoda, palaeobiogeography, palaeoecology, late carboniferous, velebit mt., croatia. figure 1. simplified geological map of the research area, with the location of brachiopod observations (black squares?) (after cleal et al., 2015). g eo lo gi a c ro at ic a geologia croatica 69/2178 the carboniferous palaeogeographic map chosen to present the carboniferous brachiopod localities is based upon blakey’s (2015) reconstruction. 3. brachiopod taxa brachiopods were discovered in carboniferous sedimentary rocks forming the core of the anticline on the continental slopes of velebit mt. (simić, 1935; salopek, 1942, 1948). brachiopods are in most cases preserved as casts and moulds (fig. 2), and it is not always possible to determine them to species level. the determined taxa belong to nine taxonomic groups: productida, orthothetida, athyridida, spiriferinida, spiriferida, rhynchonellida, orthida, dictyonellida and terebratulida (table 1.). initial brachiopod taxonomy studies were based upon several published papers (e.g. von schlotheim, 1816; waagen, 1884; schellwien, 1892, 1900; moore, 1979). taxa are revised according to the treatise on invertebrate palaeontology (selden, 2007). localities with carboniferous brachiopods can be grouped into three clusters (a, b and c) with different brachiopods (fig. 1, tab 1., 2. figs. 1, 3–7) the westernmost localities (a) are dominated almost completely by productids (linoproductus lineatus, neochonetes granulifer, paramesolobulus latesinuata, with small dielasma (tab. 1.; fig. 3 a, 4). altogether, 6 brachiopod specimens from this area are stored in the natural history museum. moving eastwards (b), brachiopod diversity increases and, the first orthotethids and rhychonellids occur (tabs. 1., 2.; figs. 3 b, 5). the eastern part of the carboniferous belt in velebit mt. and the lika region (c) comprises highly variable brachiopod assemblages, with almost a hundred specimens of productids, orthotethids, athyridids, spiriferinids, spiriferids, rhynchonellids, orthids and dictyonellids (tabs. 1., 2.; figs. 3 c, 6). all the aforementioned facies types occur in all three sampling areas (salopek, 1942, 1948; sremac, 2012), but greywackes („ fusulinid sandstones“) are more common in the older horizons, while shales and scarce limestones prevail in the younger horizons. brachiopod fossils are particularly numerous ozoans and other macrofossils (salopek, 1942, 1948; kochansky-devidé, 1955, 1970; sremac, 2005, 2012). a rich fossil assemblage from these deposits has been collected during mapping campaigns undertaken by m. salopek and his students between 1935 and 1938 (salopek, 1942, 1948). the geological setting of the wider area is described in basic geological maps of yugoslavia on the 1:100000 scale and basic geological map of croatia 1:300 000 (ivanović et al., 1973, 1976; sokač et al., 1974, 1976a, b, c; velić et al., 2009). mixed siliciclastic-carbonate deposition is typical for the late carboniferous of this region. the stratigraphic age (late kasimovian or earliest gzhelian) was determined from microfossils and land megaflora (kochansky-devidé, 1955, 1970; sremac, 2012; cleal et al., 2015). different lithological units in the carboniferous of velebit mt. were recognized quite early by salopek (1942, 1948). marine macrofossils, including the brachiopods (simić, 1935), were discovered in three lithological types: yellowish-brown shales and siltstones (cau, equivalent to the auernig beds according to salopek, 1942, 1948), limestones (cv, according to salopek, 1942, 1948) and greywackes („fusulinid sandstones“, cf, according to salopek, 1942, 1948). „fusulinid sandstones“ are more common in the lower horizons of the late carboniferous sequences, estimated to be of kasimovian age, with overlying yellowish shales and siltstones of late kasimovian to gzhelian age (kochansky, 1955; sremac, 2012). the diversity of marine fossils, including brachiopods increases from the kasimovian to gzhelian horizons (sremac, 2012). 2. materials and methods carboniferous brachiopods from this study were collected by salopek (1942, 1948) and by the present authors between 20122014. the brachiopod collection is stored in the croatian natural history museum (under 96 inventory numbers). all together 110 brachiopod specimens were determined and/or revised (selden, 2007; emig et al., 2013; paleobiology database; www.fossilworks.org and references therein; august 2015) and asserted to 63 taxa. figure 2. modes of preservation of late carboniferous brachiopods in the velebit mt.: a) inner cast (with gaps in places of dissolved median septa) – area c; b) partly preserved shell and inner cast with visible median septum – area c; c) cast with visible external ornamentation, surrounded with fusulinid casts – area c. (scale bar 1cm) g eologia c roatica mirko japundžić and jasenka sremac: palaeobiogeography of the late carboniferous brachiopoda from velebit mt. (croatia) 179 table 1. list of carboniferous brachiopod taxa grouped through localities in the velebit mt. and facies types. (simić, 1935; salopek, 1942, 1948 and own research revised). class/order/genus/species localities (w®e) facies   a (1-4) b (5-6) c (7-11) cau cv cf strophomenata             productida             breileenia echidniformis (grabau in chao) chaoiella gruenewaldti (krotov) chonetes mamontovi chonetes papilionacea (phillips) chonetes sp. comuquia curvirostris (schellwien) cubacula subpunctata (nikitino) echinoconchus elegans norwood and pratten echinoconchus punctatus (martin) incisius incisus (schellwien) linoproductus lineatus waagen linoprodutus sp. marginifera pusilla schellwien megousia aagardi (toula) neochonetes granulifer (owen) neochonetes variolata (d’orbigny) neochonetes (sommeriella) strophomenoides waagen paramesolobus latesinuata schellwien   plicatifera sp. productus mölleri productus transversalis tschernyschew productus sp. productus cf. longispinus sowerby transennatia gratiosa (waagen) vediproductus punctatiformis chao waagenoconcha sp. orthothetida derbya (derbyia) altestriata waagen derbya (derbyia) cf. grandis waagen derbya (derbyia) sp. meekella sp. streptorhynchus pelargonatus schlotheim streptorhynchus semiplanus (waagen) streptorhynchus sp. rhynchonellata athyridida retzia sp. hustedia mormoni (marcou) spiriferinida callispirina ornata waagen spiriferellina cristata (schlotheim) spiriferina sp. spiriferina laminosa (mccoy) spiriferida alphachoristites trautscholdi stuckenberg ambocoelia sp. bajkuria rostrata kutorga choristites fritschi (schellwien) choristites sp. elinoria carnica (schellwien) eliva lyra (kutorga) martinia semiplana (waagen) martinia sp. neospirifer cameratus (morton) neospirifer fasciger (keyserling) plicatocyrtia zitteli (schellwien) reticularia lineata (martin) reticularia sp. spirifer sp. squamularia sp. rhynchonellida hustedia mormoni (marcou) rhynchonella aff. confinensis schellwien stenoscisma alpinum (schellwien) uncinunellina timorensis (beyrich) orthida rhipidomella pecosi (marcou) enteletes sp. dictyonellida isogramma paotechovensis grab terebratulida dielasma sp. g eo lo gi a c ro at ic a geologia croatica 69/2180 and diverse in the shales and siltstones (cau, equivalent to the auernig beds according to salopek, 1942, 1948). a different fossil assemblage is preserved in the limestones (cv, according to salopek, 1942, 1948). only a few brachiopod taxa were observed in the greywackes („fusulinid sandstones“, cf, according to salopek, 1942, 1948) (tab. 1.). 4. discussion 4.1. palaeoecology and the local distribution of brachiopod genera brachiopod finds are clearly grouped into three areas with different fossil assemblages (tabs. 1., 2., fig. 3). palaeobiodiversity evidently increases towards the east (tab. 2., fig. 8). it is important to note that these three areas very rarely comprise the same taxa (tab. 1). the exceptions are several tolerant taxa, capable of adapting to a variety of marine environments, such as linoproductus lineatus (present in all three areas and in all lithological units – shales and siltstones, greywackes and limestones), or transennatia gratiosa, present in the central and eastern areas, and in two of the three lithological units (shales and siltstones; limestones) (tab. 1.). the western area (a, fig. 1) is characterized by several small productid taxa, with the exception of the larger linoproductus (tabs. 1., 2., figs. 4 a, b). they lived anchored by spines on the soft bottom, with low depositional rates. their low diversity and small size probably indicate restricted food sources. the central area (b, figs. 1, 3 b, 5 a-d), comprises some orthotethids and rhyncnonellids (tabs. 1., 2; figs. 5 b, c) in addition to the productids. linoproductus and transennatia (figs. 5 a, d) discovered in this area could have lived in different marine environments, from open subtidal, to basinal areas. the presence of neochonetes variolata (fig. 4 a) indicates a most probable deep subtidal depositional area (kalashnikov, 1993). rhynchonella confinensis seems to be endemic, occurring only in velebit mt. and in the permian deposits in neighbouring slovenia (schellwien, 1892). the eastern area (c, fig. 1) is generally rich in fossils. a well preserved terrestric megaflora indicates the vicinity of land (sremac, 2012; cleal et al., 2015). marine fossils are diverse, with a predomination of fusulinids and crinoid ossicles, together with calcareous algae, brachiopods (figs. 6 a-h), bryozoans (fig. 7 a), bivalves (fig. 7 b) and gastropods (simić, 1935; salopek, 1948; kochansky-devidé 1955, 1970; sremac, 2012). figure 4. mould of a linoproductus brachial valve (a) and bioeroded cast of productus transversalis tschernyschew (b) from locality cluster a. (scale bar 1cm) figure 3. differentiation of facies and brachiopod assemblages in the three examined areas with carboniferous deposits in velebit mt.: a) westernmost area (a) comprises large fenestellid casts and rather small brachiopods; b) central area (b) is characterized by the domination of flattened orthotethids; c) eastern localities (area c) comprise an abundant and variable brachiopod fauna, with the predomination of productida. (scale bar 1cm) g eologia c roatica mirko japundžić and jasenka sremac: palaeobiogeography of the late carboniferous brachiopoda from velebit mt. (croatia) 181 figure 5. transennatia (a), derbya, (b,c) and segment of linoproductus (d) with visible spine bases from the locality b. (scale bar 1cm) figure 6. productid genera (a-f ): productus (a, c, e), dictyoclostus (b), linoproductus (d) and marginifera (f ), spiriferinid (spiriferina sp.) (g) and the spiriferid (choristites) (h) brachiopoda from locality group c. (scale bar 1cm) g eo lo gi a c ro at ic a geologia croatica 69/2182 trace fossils are common in the sandstones and siltstones, present on bedding surfaces, but also within the layers, and can be attributed to the scolithos ichnofacies. well sorted conglomerates and the aligned orientation of fusulinids in some sandstone layers indicate a the coastal environment. partial or complete dissolution of fusulinid tests (salopek, 1948; kochansky, 1955) indicate a probable fresh-water influence (sremac, 2012). brachiopods, although numerous and highly diverse, are also mostly present as casts or moulds (figs. 1-6). all these features indicate a variety of environments, from beaches to the more favourable subtidal niches. erosion of the uplifted variscan mountains provided nutrients and enabled the significant diversification of marine biota. similar trends were described from spain (winkler prins, 2007; merino-tomé et al., 2009). 4.2. palaeobiogeographic studies the late carboniferous was a time of a slight increase in brachiopod diversity (shu-zhong et al., 2006) and these organisms were present in all seas and oceans. their geographic distribution was closely related to the position of continental shelves and possible sea-ways and climate gradients, recently studied by several authors (angiolini et al., 2007; berra & angiolini, 2014). during the late carboniferous, the study area was a part of ne gondwana, situated near the equator (vozarova et al., 2009; sremac, 2012; cleal et al., 2015) figure 7. cast of a fenestellid bryozoan (a) and a scallop acantopecten sp.(b) from locality group c. (scale bar 1cm) table 2. total number of brachiopod taxa in three different carboniferous areas in velebit mt. locality group a,b, c facies brachiopod group taxa a (1–4) b (5–6) c (7–11) cau cv cf productida 26 5 3 24 23 9 1 orthothetida 7 0 3 4 5 2 0 athyridida 2 0 0 2 2 0 0 spiriferinida 4 0 0 4 3 1 0 spiriferida 16 0 0 16 15 4 0 rhynchonellida 4 0 1 3 2 0 1 orthida 2 0 0 2 2 0 0 dictyonellida 1 0 0 1 1 0 0 terebratulida 1 1 0 0 1 0 0 63 6 7 56 54 16 2 figure 8. total brachiopod diversity and area specific diversity for the three carboniferous areas in velebit mt. g eologia c roatica mirko japundžić and jasenka sremac: palaeobiogeography of the late carboniferous brachiopoda from velebit mt. (croatia) 183 in order to identify possible migration routes, some of the common carboniferous brachiopod genera from velebit mt. were selected for further palaeobiogeographic studies. tolerant brachiopod taxa (neospirifer, derbya) were widely spread. disocveries of neospirifer have been recorded in almost a thousand carboniferous and permian collections all over the world (pederson, 1954; sutherland, 1991; kora, 1995; kala shnikov, 1998; sobolev et al., 1998; wendt et al., 2001; schneider, 2003; gong et al., 2007; http://fossilworks.org, 2016 and references therein). they lived all along the continental shelves of euramerica, but also on the shelves of the southern continents and islands (fig.9). it is possible that they had a rather longlived swimming larval stage. the genus chonetes was also widespread, present all around euramerica (fig. 9). however, the geographic range of the genus echinoconchus is very peculiar (fig. 10) indicating possible migrations along the shelves of panthalassa, rather than those of palaeotethys. the genus megousia was common on the northern shelves of euramerica and its apfigure 9. the distribution of the late carboniferous cosmopolitan brachiopod genera (neospirifer, derbya, chonetes, observed in velebit mt. (records from: pederson, 1954; sutherland, 1991; kora, 1995; kalashnikov, 1998; sobolev et al., 1998; wendt et al., 2001; schneider, 2003; gong et al., 2007; http://fossilworks.org/ and references therein). palaeobiogeography based upon blakey’s (2016) reconstruction. grey colour: continents; white colour: oceans/seas; ps: palaeotethys; pa: panthalassa; g: gondwana; ea: euroamerica. study area indicated by the arrow. g eo lo gi a c ro at ic a geologia croatica 69/2184 pearance near the equator is interesting (fig. 10). alternatively, the genus transenatia is rather endemic, appearing on the eastern continental shelves of euramerica, near the equator (fig. 10). 5. conclusions the carboniferous brachiopod fauna from velebit mt. is very rich and diverse. but in most cases not well preserved. all together 63 taxa were determined, belonging to nine brachiopod groups, with a predominance of productids and spiriferids. brachiopods were observed in the form of moulds and casts in shales and siltstones, limestones and graywackes, with the highest abundance in fine-grained clastic deposits. three different areas with diverse brachiopod associations can be clearly recognized. the highest brachiopod diversity was observed in coastal fine-grained clastic deposits at the eastern part of the outcropping carboniferous rock belt. a kasimovian to gzhelian age was proposed on the basis of the associated fusulinid fauna. figure 10. distribution of the late carboniferous specialist brachiopod genera (echinoconchus, megousia, transennatia, observed in velebit mt. (observations from: pederson, 1954; sando et al., 1975; schneider, 2003; gong et al., 2007; heim et al., 2009; http://fossilworks.org/ and references therein). palaeobiogeography based upon ron blakey’s reconstruction (http://cpgeosystems.com/300marect.jpg, july 2015). grey colour: continents; white colour: oceans/seas; ps: palaeotethys; pa: panthalassa; g: gondwana; ea: euroamerica. study area marked by arrow. g eologia c roatica mirko japundžić and jasenka sremac: palaeobiogeography of the late carboniferous brachiopoda from velebit mt. (croatia) 185 during the late carboniferous, brachiopods were common along the continental shelves of euroamerica. southern hemisphere records are less common and represented by tolerant gene ra, e.g. the cosmopolitan neospirifer and derbya. acknowledgement the authors are grateful to sanja japundžić (croatian natural history museum) for the macrophotography of the brachiopods and robert koščal (faculty of science, university of zagreb) for preparation of graphics, and to both reviewers for their contribution in the improvement of the manuscript. references angiolini, l., gaetani, m., muttoni, g., stephenson, m.h. & zanchi, a. (2007): tethyan oceanic currents and climate gradients 300 m.y. ago.– geology, 35/12, 1071–1074. doi: 10.1130/g24031a.1 berra, f. & angiolini, l. (2014): the evolution of the tethys region throughout the phanerozoic: a brief tectonic reconstruction.– in: marlow, l., kendall, c. & yose, l. (eds.): petroleum systems of the tethyan region. aapg memoir, 106, 1–27. cleal, c.j., tenchov, y.g., sremac, j., đerek, t. & japundžić, s. (2015): pennsylvanian fossil flora from the velebit mountains and lika region (sw croatia).– bulletin of geosciences. emig, c.c.; bitner, m.a.; & alvarez, f. (2013): phylum brachiopoda.– zootaxa 3793/1, 75–78 [p. wagner/p. wagner] gong, e., samankassou, e., guan, c., zhang, y. & sun, b. (2007): paleoecology of pennsylvanian phylloid algal buildups in south guizhou, china.– facies, 53, 615–623 [w. kiessling/u. merkel] heim, n.a. (2009): stability of regional brachiopod diversity structure across the mississippian/pennsylvanian boundary.– paleobiology, 35/3, 393. ivanović, a., sakač, k., marković, s., sokač, b., šušnjar, m., nikler, l. & šušnjara, a. (1973): osnovna geološka karta sfrj 1:100000, list obrovac l33-140 [basic geologic map of sfry 1:100000, obrovac sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd. ivanović, a., sakač, k., sokač, b. & vrsalović-carević, i. (1976): osnovna geološka karta sfrj 1:100000, tumač za list obrovac l33-140 [basic geologic map of sfry 1:100000, geology of obrovac sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd, 61 p. kalashnikov, n.v. (1993): brakhiopody permi evropeiskogo severa rossyy [permian brachiopods from the european northern russia – in russian], 151 p. nauka, sankt-peterburg. kalashnikov, n.v. (1998): permian spiriferids from the north of european russia 1-139 [m. clapham/m. clapham/m. clapham] kochansky-devidé, v. (1955): karbonske i permske fuzulinidne foraminifere velebita i like i. opći dio i karbon [carboniferous and permian fusulinids of the velebit mt. and lika region. introduction and carboniferous − in croatian].− rad jugosl. akad., 305, 5−62, zagreb. kochansky-devidé, v. (1970): die kalkalgen des karbons vom velebit-gebirge (moskovien und kassimovien).− palaeont. jugosl., 10, 32 p. kora. m. (1995): carboniferous macrofauna from sinai, egypt: biostratigraphy and paleogeography.– journal of african earth sciences 20/1, 37–51 [l. ivany/p. wall/p. wall] merino-tomé, o., bahamonde, j.r., samankassou, e. & villa, e. (2009): the influence of terrestrial run off on marine biotic communities: an example from a thrust-top carbonate ramp (upper pennsylvanian foreland basin, picos de europa, nw spain).− palaeogeogr., palaeoclimat., palaeoecol., 278/1−4, 1−23. doi: 10.1016/j.palaeo.2009.04.002 m moore, r.c. (1979): treatise on invertebrate paleontology part h, brachiopoda. the geological society of america, inc. and university of kansas boulder. colorado and lawrence, kansas. 1–554. pederson, s.l. (1954): a permian (wolfcampian) fauna of the casper formation of southeastern wyoming.– journal of paleontology, 28/1, 17–21[j. alroy/j. alroy] salopek, m. (1942): o gornjem paleozoiku velebita u okolici brušana i baških oštarija [on the upper palaeozoic of the velebit mt. in the vicinity of brušane and baške oštarije – in croatian].− rad jazu., 274, 218−272. salopek, m. (1948): o gornjem paleozoiku sjeveroistočnog podnožja velebita i like [on the upper palaeozoic of the northeastern slope of the velebit mt. and lika region – in croatian].− rad jazu, 274, 75 p. sando, w., gordon, j.m. & dutro, jr.j.t. (1975): stratigraphy and geologic history of the amsden formation [mississippian and pennsylvanian] of wyoming. united states geological survey professional paper 848a:1–83 schellwien, e. (1892): die fauna des karnischen fusulinenkalks, palaeontographica, 39, 1–56. schellwien, e. (1900). die fauna der trogkofelschichten in den karnischen alpen und den karawanken i. theil: die brachiopoden. abhandlungen der kaiserlichköniglichen geologischen reichsanstalt, 1–122. selden, p.a. (2007): treatise on invertebrate paleontology, part h, brachiopoda (revised), vol. 6. geological society of america, boulder, colorado and university of kansas press, lawrence, kansas, 956 p.shu-zhong, s., hua, z., wen-zhong, l., lin, m., jun-fang, z., (2006): brachiopod diversity patterns from carboniferous to triassic in south china.–geol. j., 41, 345–361. simić, v. (1935): gornjokarbonski fosili iz like u hrvatskoj [late carboniferous fossils from lika in croatia – in serbian].− vesnik geol. inst. kralj. jugosl, 1/1, 141−145. sobolev e.s., budnikov, i., v., klets a.g., grinenko, v.s. (1998): late bashkirian ammonoids and nautiloids from western verkhoyansk region.– paleontological journal 32/5, 13–25 [j. alroy/c. simpson/c. simpson] sokač, b., bahun, s., velić, i. & galović, i. (1976a): osnovna geološka karta sfrj 1:100000, tumač za list otočac l 33-115 [basic geologic map of sfry 1:100000, geology of otočac sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd, 44 p. sokač, b., nikler, l. & velić, i. & mamužić, p. (1974): osnovna geološka karta sfrj 1:100000, list gospić l 33-127 [basic geologic map of sfry 1:100000, gospić sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd. sokač, b., ščavničar, b. & velić, i. (1976b): osnovna geološka karta sfrj 1:100000, tumač za list gospić l 33-127 [basic geologic map of sfry 1:100000, gospić sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd, 64 p. sokač, b., šušnjar, m., bukovac, j. & bahun, s. (1976c): osnovna geološka karta sfrj 1:100000, tumač za list udbina l33128 [basic geologic map of sfry 1:100000, geology of udbina sheet − in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd, 62 p. sremac, j. (2005): equatorial shelf of the palaeozoic supercontinent – cradle of the adriatic carbonate platform.− geol. croat., 58/1, 1−19. sremac, j. (2012): influence of terrestrial sedimentation in pennsylvanian rocks of croatia.– geol. croat., 65/3, 274–277. sutherland, p., k. (1991): morrowan brachiopods from the type „derryan“ series (pennsylvanian), southern new mexico.– new mexico bureau of mines and mineral resources bulletin, 137,186–188 [j. alroy/c. simpson/c. simpson] velić, i., šparica, m. & vlahović, i. (2009): klastične i karbonatne naslage (karbon, perm – c, p) [clastic and carbonate deposits (carboniferous, permian – c, p) – in croatian].– in: velić, i. & vlahović, i. (eds.): explanatory text for geologic map of croatia 1: 300000. hrvatski geološki institut, 20−23. von schlotheim, e.f. (1816): beiträge zur naturgeschichte der versteinerungen in geognostischer hinsicht. denkschriften der königlich akademie der wissenschaften zu munchen für des jahre 1816 und 1817, 6, 13–36. vozarova, a., ebner, f., kovacs, s., kräutner, h.-g., szederkenyi, t.krstić, b., sremac, j., aljinović, d., novak, m. & skaberne, d. (2009): late variscan (carboniferous to permian) environments in the circum pannonian region.– geol. carpath., 60/1, 71−104. doi: 10.2478/v10096-009-0002-7 waagen, w. (1884): productus limestone fossils, part iv, fas. 4.– salt range fossils, palaeontologia indica, 611–728. wendt, j., kaufmann, b. & belka, z. (2001): an exhumed palaeozoic underwater scenery: the visean mud mounds of eastern anti-atlas [morocco].– sedimentary geology, 145, 215–233 [w. kiessling/u. merkel] winkler prins, c.f. (2007): the role of spain in the development of the reef brachiopod faunas during the carboniferous.– in: renema, w. (ed.): biogeography, time, and place: distributions, barriers, and islands, 217–246 web sources http://cpgeosystems.com/300marect.jpg, last checked april 2016 http://peabody.yale.edu/sites/default/files/documents/invertebrate-paleontology/re vised%20treatise.pdf, last checked april 2016 www.fossilworks.org, last checked april 2016 1. introduction the purpose of this paper is to provide an overview of the late carboniferous floras of slovenia which is poorly known to potential readers as information is mainly documented in local reports. the flora is generally much poorer, but comparable to those from the west and central european coalfields, yet it is indisputably of significant importance for palaeogeographic considerations and stratigraphic correlations. the post-variscan carboniferous and permian strata with fossil megafloras in slovenia crop out in the geotectonic units of the southern alps and external dinarides (figs. 1, 2). in central slovenia, upper palaeozoic rocks, particularly the clastic sedimentary deposits, provide a soft bed for the nappe structure of the external dinarides (placer, 1999). owing to the complicated tectonic structure, a lack of marker horizons and scarce fossil remains, the thick monotonous clastic sedimentary sequence underlying the val gardena formation was assigned both carboniferous and permian ages. in central slovenia, these strata are represented in the sava folds (winkler, 1923) that are composed mainly of quartz conglomerate, sandstone, siltstone and shaly claystone. occurrences of palaeozoic flora of the sava folds were previously reported in the nineteenth century and in the first half of the twentieth century by morlot (1850), hauer (1851), lipold (1857, 1858), kossmat (1913), tornquist (1929) and rakovec (1932). later studies on the megaflora of the sava folds were published by kolarjurkovšek & jurkovšek (1985, 1986, 1990, 2002a, 2002b, 2007). sections of the late carboniferous in the southern karavanke mountains are commonly exposed in narrow belts or scattered outcrops as a result of strong alpine tectonics (buser, 1980; jurkovšek, 1987). the composite carboniferous and permian lithostratigraphical column can be well correlated with the standard zonation in the carnic alps that is formed of the pontebba supergroup, (auernig formation, rattendorf group and trogkofel group) (novak, 2007). a late carboniferous megaflora from the southern karavanke mountains was reported by morlot (1850), stur (1886) and ramovš (1978). 2. material the geological survey of austria in vienna hosts the oldest but very small collection of plant fossils that was obtained by various field geologists during the austrian-hungarian monarchy and determined by ettinghsausen. moreover, some other specimens are scattered in the collections of the faculty of natural sciences and engineering of the university of ljubljana and the slovenian natural history museum in ljubljana. ab stra ct this paper provides a short review of the late carboniferous floras in slovenia. the namurian-westphalian or westphalian a (langsettian) flora was collected in the sava folds, whereas the late westphalian and/or stephanian flora was documented in the southern karavanke mts. the recovered assemblages are well represented by horsetails, arborescent lycopsids, fern-like foliage (ferns and pteridosperms) as well as gymnosperms, and they correspond to the general features of the euramerican flora. keywords: megaflora, late carboniferous, slovenia geologia croaticageologia croatica late carboniferous floras of slovenia – a review  tea kolar-jurkovšek and bogdan jurkovšek geological survey of slovenia, dimičeva ulica 14, si-1000 ljubljana, slovenia; (tea.kolar@geo-zs.si, bogdan.jurkovsek@geo-zs.si) doi: 104154/gc.2012.21 geologia croatica 65/3 323–328 9 figs. 1 tab. zagreb 2012 geologia croatica 65/3geologia croatica 324 a significant flora from the javorniki area containing about a hundred specimens is housed at the gornjesavski muzej in jesenice. this was collected by jože bedič and it still needs a detailed systematic description. the material collected and studied by the present authors consists of about one hundred specimens and it was derived from the sava folds. it is housed in the jurkovšek palaeontological collection that has been registered with the slovenian natural history museum, as well as the geological survey of slovenia, and it is partly exhibited at a permanent exhibition at ljubljana castle. 3 geological settings and paleontological remarks 3.1. sava folds in the wider region of the sava folds, the palaeozoic strata of the trojane and litija anticline form the basement of the shallow water (platform) carbonates of the external dinarides. the basic lithological members are quartz conglomerate, quartz sandstone, siltstone and mudstone. based on all previous knowledge and his own detailed investigations, mlakar (1987, 1994) increased understanding of the sava folds geological structure, by proposing subdivision of the palaeozoic sequence into three superpositional units of the first order (ca, cb and cc), that could represent three formations, or three members of the same formation (fig. 3). the second superposition unit (cb) was subdivided into four units. the cb2 subunit has been dated on palaeontological data and attributed a namurian – westphalian a (langsettian) age (kolar-jurkovšek & jurkovšek, 1985, 1986, 1990, 2002a, 2002b, 2007). the megaflora was collected from numerous localities between ljubljana and polšnik near litija (figs. 4, 5) and it is well-represented by horsetails (calamites), arborescent lycopsids (lepidodendron, sigillaria, stigmaria), fern-like foliage (ferns and pteridosperms), and gymnosperms (cordaites). the westernmost locality of the sava folds is at ljubljana castle hill and the age of the recovered plant assemblage here is based on the species neuropteris tenuifolia figure 1: simplified geological map of slovenia based on data of the basic geologic map of sfry 1:100000 compiled by buser for the geologic map of the republic of slovenia 1:250 000 (buser, 2010). a – southern alps, b – sava folds. figure 2: distribution of tectonic plates in the late carboniferous. red dot indicates the palaeogeographic position of slovenia on the world map (scotese, 2002). kolar-jurkovšek and jurkovšek: late carboniferous floras of slovenia – a review geologia croatica 325 schlotheim, n. cf. heterophylla brongniart and cordaites palmaeformis (goeppert), as well as the presence of certain mesocalamite-like forms (calamites (mesocalamites) roemeri goeppert, c. (m.) cf. cistiiformis stur) (fig. 6). therefore the strata with flora from this locality are attributed to the lower part of the westphalian a (langsettian substage) (kolar-jurkovšek & jurkovšek, 2007). 3.2. southern karavanke mts. late palaeozoic beds in the southern karavanke mountains are commonly exposed in narrow bands or scattered outcrops as a result of a strong overprint by alpine tectonics. however, the composite lithostratigraphic column displays a very similar succession compared to the pontebba supergroup (auernig formation, rattendorf group and trogkofel group) in the carnic alps, which are a morphological and orographic continuation of the southern karavanke mountains (kahler, 1985; schönlaub, 1985; krainer, 1993; novak & skaberne, 2009). the pennsylvanian rocks of the western karavanke mountains were described as the javornik beds based on fusulinid foraminifera (kochansky-devide & ramovš, 1966; ramovš & kochansky-devide, 1979). later, novak (2007) considered the javornik beds to be an equivalent of the auernig beds, and he presented a new lithostratigraphic subdivision with the kasimovian (protriticites) beds in their lowermost part (fig. 7). in general the auernig formation consists of conglomerates, sandstones and shales with lenses of limestones containing fusulinid and conodont faunas. fossil megafloras were collected mostly in the gzhelian strata of the javornik beds in the area north of jesenice, and the determined list includes polymorphopteris polymorpha (brongniart) and annularia stellata (schlotheim) (fig. 8), as well as lepidodendron cf. scutatum lesquereux and sigillaria brardi brongniart as reported by ramovš (1978). a small flora from the planina locality below the golica mt. was studied but not illustrated by takšić (1947), and the following species were determined: pecopteris aff. arborescens brogniart, alethopteris serlii brongnifigure 3: lithostratigraphic subdivision of the first tectono-sedimentary cycle in the sava folds (modified after mlakar et al., 1993). figure 6: fossil flora from ljubljana castle hill: a – calamites (mesocalamites) roemeri goeppert, b – calamites (mesocalamites) cf. cistiiformis stur, c – calamites sp., d – cyperites bicarinatus lindley & hutton, e – neuropteris tenuifolia schlotheim. photo bogdan jurkovšek. figure 4: one of the richest localities of carboniferous plant fossils in the sava folds at zavrstnik near litija. the fossiliferous bed is marked with the geologic hammer (kolar-jurkovšek & jurkovšek, 2002a). photo bogdan jurkovšek. figure 5: plant fossils from ljubljana environs (locality bizovik). a – pecopteris sp., specimen height 5.5 cm; b – lepidodendron cf. aculeatum sternberg, specimen height 4 cm. photo bogdan jurkovšek. geologia croatica 65/3geologia croatica 326 art, alethopteris grandini brongniart, neuropteris ovata hoffmann, neuropteris sp., sphenophyllum sp., annularia stellata (schlotheim) wood, calamites rimosus artis, calamites sp. and lepododendron rimosum sternberg. takšić (1947) compared this flora with the flora from certain locations in austria and regarded it as being of asturian or early stephanian age (highest westphalian d or lower stephanian), table 1: comparison of pennsylvanian flora in the investigated localities of the sava folds based on the original determinations of the authors (after kolar-jurkovšek & jurkovšek, 2007). litija environs bizovik ljubljana castle hill calamites (mesocalamites) haueri stur x calamites (mesocalamites) ramifer stur x calamites (mesocalamites) cf. ramifer stur x x calamites (mesocalamites) roemeri goeppert x x x calamites (mesocalamites) cf. roemeri goeppert x calamites (mesocalamites) cistiiformis stur x calamites (mesocalamites) cf. cistiiformis stur x x calamites (stylocalamites) suckowi brongniart x x calamites (stylocalamites) cf. suckowi brongniart x calamites (stylocalamites) cf. cisti brongniart x calamites (stylocalamites) undulatus sternberg x x calamites (stylocalamites) cf. undulatus sternberg x x calamites (calamitina) sachsei stur x calamites (calamitina) schuetzeiformis kidston & jongmans x calamites sp. x x x equistetites cf. hemingwayi kidston x lepidodendron cf. aculeatum sternberg x x lepidodendron iycopodioides sternberg x lepidodendron sp. x x x lepidostrobus sp. x asolanus comptotaenia wood x ? asolanus sp. x sigillaria boblayi brongniart x sigillaria cf. boblayi brongniart x sigillaria mamillaris brongniart x sigillaria elegans (sternberg) brongniart x sigillaria sp. (syringodendron – rhytidolepis) x x x sigillaria sp. x x cyperites bicarinatus lindley & hutton x stigmaria ficoides (sternberg) brongniart x x stigmaria ficoides var. undulata goeppert x figure 8: upper carboniferous fossil plants polymorphopteris polymorpha (brongniart) and annularia stellata (schlotheim). planina pod golico, karavanke mts. sample width 14 cm. photo jože bedič. figure 7: stratigraphic column of carboniferous strata in the south karavanke mountains (modified after novak & skaberne, 2009). kolar-jurkovšek and jurkovšek: late carboniferous floras of slovenia – a review geologia croatica 327 4. conclusions the upper palaeozoic deposits, exposed in a broad belt between ljubljana and polšnik, have been the subject of detailed palaeontological, sedimentological, and structural studies for many years. they were the basis for various, and often conflicting interpretations of accurate age, depositional environment, and structure of the so-called permo-carboniferous beds of the sava folds. the recovered assemblages which were collected during recent decades in the second superposition member (cb2) can be considered as representing the hydrophile to hygrophile flora that populated wet habitats of the swamp area. a large proportion of pteridosperms and the presence of cordaites suggest growth on somewhat elevated parts of the river bank, at the margin of the flood area, as indicated by the abundant presence of articulates. the age of the determined assemblages can be estimated based on the stratigraphic ranges of certain neuropterid species that range in the westphalian, however some of them already appear in the namurian. the presence of some mesocalamites-like forms in the locations close to ljubljana intable 1: continued. litija environs bizovik ljubljana castle hill stigmaria cf. ficoides (sternberg) brongniart x pecopteris (senftenbergia) cf. plumosa (artis) brongniart x pecopteris sp. x eusphenopteris sp. x x ? mariopteris sp. x neuropteris tenuifolia schlotheim x x neuropteris cf. heterophylla brongniart x neuropteris sp. x x ? neuropteris sp. x linopteris neuropteroides (gutbier) zeiller x linopteris sp. ali reticulopteris sp. x linopteris sp. x trigonocarpus sp. x x x ? carpolithus sp. x noeggerathia sp. x cordaites palmaeformis (goeppert) x cordaites principalis (germar) x cordaites cf. principalis (germar) x cordaites sp. x x x cordaicladus sp. x artisia approximata lindley & hutton x ? artisia sp. x dicate the lower part of the westphalian (kolarjurkovšek & jurkovšek, 2002a, 2007) (tab. 1). the fossil flora of the karavanke mts. occurs in the javornik beds and shows a great similarity with the flora of the auernig beds of the pontebba supergroup. a well preserved megaflora was collected in some locations in the area north from jesenice. however, most assemblages have not been part of a detailed study. the megaflora is abundantly represented in the upper carboniferous strata and the recognized assemblages are similar to the late westphalian and /or early stephanian floras of the carnian alps. the recovered plant assemblages from the localities of the sava folds (fig. 9) and southern karavanke mountains are similar to the coeval fossil floras of neighbouring areas (fritz et al., 1990; ronchi et al., 2012; sremac, 2012) and they correspond in their general features to the euramerican flora. acknowledgement this is a contribution to the igcp-project 575 “pennsylvanian terrestrial habitats and biotas of southeastern euramerica”. dr. yanaki tenchov and dr. stanislav opluštil are acknowledged for their review of the manuscript and suggestions for its improvement. dr. chris cleal made linguistic corrections. references buser, s. (1980): osnovna geološka karta sfrj 1:100000. tolmač lista celovec (klagenfurt) [basic geologic map of sfry 1:100000, geology of the celovec (klagenfurt) sheet – in slovenian].– zvezni geološki zavod, beograd, 62 p. buser, s. (2010): geološka karta slovenije [geological map of slovenia – in slovenian].– geološki zavod slovenije, ljubljana. fritz, a., boersma, m. & krainer, k. (1990): pflanzen fossilien aus kärnten.– carinthia ii, sonderheft, klagenfurt, 49, 189 p. hauer, f. v. (1851): nachricht über die sammlung in laibach.– mitt freunde naturwiss, 7/4, 139–140. figure 9: reconstruction of upper carboniferous landscape based on fossils collected in slovenia (by barbara jurkovšek, 2006). geologia croatica 65/3geologia croatica 328 jurkovšek, b. (1987): osnovna geološka karta sfrj 1:100000. tolmač lista beljak (villach in ponteba) [basic geologic map of sfry 1:100000. geology of the beljak (villach and pontebba) sheet – in slovenian].– zvezni geološki zavod, beograd, 58 p. kahler, f. (1985): oberkarbon und unterperm der karnischen alpen: ihre biostratigraphie mit hilfe der fusuliniden. – carinthia ii, 42, sonderheft, klagenfurt, 93 p. kochansky-devidé, v. & ramovš, a. (1966): zgornjekarbonski mikrofosili in stratigrafski razvoj v zahodnih karavankah.– razprave 4. razr. sazu, ljubljana, 9, 299–333. kolar-jurkovšek, t. & jurkovšek, b. (1985): nova nahajališča paleozojske flore v posav skih gubah med ljubljano in litijo.– razprave iv. razr. sazu, 26, 199–218. kolar-jurkovšek, t. & jurkovšek, b. (1986): karbonska (westfalijska) makroflora iz za vrstnika.– rud.-metal. zbor., 33/1–2, 3–34. kolar-jurkovšek, t. & jurkovšek, b. (1990): karbonska makroflora med jančami in polšnikom v posavskih gubah.– rud.-metal. zbor., 37/3, 367–389. kolar-jurkovšek, t. & jurkovšek, b. (2002a): karbonski gozd. karbonske plasti z rastlinskimi fosili pri ljubljani [carboniferous forest. carboniferous strata with plant fossils near ljubljana].– geološki zavod slovenije, ljubljana, 191 p. kolar-jurkovšek, t. & jurkovšek, b. (2002b): rastlinski fosili v karbonskih plasteh na trasi avtoceste pri bizoviku.– geologija, 45/2, 433–438. kolar-jurkovšek, t. & jurkovšek, b. (2007): zgornjekarbonska flora grajskega hriba v ljubljani [late carboniferous flora of castle hill in ljubljana (slovenia) – in slovenian].– geologija, 50/1, 9–18. kossmat, f. (1913): die adriatische umran dung in der alpinen faltenregion.– mitt. geol. ges., 6, 61–165. krainer, k. (1993): lateand post-variscan sediments of the eastern and southern alps.– in: raumer, j.f. von & neubauer, f. (eds.): pre-mesozoic geology in the alps. springer-verlag, berlin, 537–549. lipold, m.v. (1857): bericht über die geolo gischen aufnahmen in oberkrain im jahre 1856.– jb. geol. r.-a. wien, 8, 205–234. lipold, m.v. (1858): bericht über die geo logischen aufnahmen in unter-krain im jahre 1857.– jb. geol. r.-a. wien, 257–276. mlakar, i. (1987): prispevek k poznavanju geo loške zgradbe posavskih gub in njihovega južne ga obrobja.– geologija, 28/29 (1985/86), 157–182. mlakar, i. (1994): o problematiki litijskega rudnega polja.– geologija, 36 (1993), 249–338. mlakar, i., skaberne, d. & drovenik, m. (1993): o geološki zgradbi in orudenju v kar bonskih kameninah severno od litije.– geologi ja, 35 (1992), 229–286. morlot, a. v. (1850): über die geologischen verhältnisse von oberkrain.– jb. geol. r.-a. wien, 389–411. novak, m. (2007): depositional environment of upper carboniferous – lower permian in karavanke mountains (southern alps, slovenia) [sedimentacijsko okolje zgornjekarbonskih in spodnjepermskih plasti v karavankah (južne alpe, slovenija) – in slovenian].– geologija, 50/2, 247–268. novak, m. & skaberne, d. (2009): zgornji karbon in spodnji perm [upper carboniferous and lower permian – in slovenian].– in: pleničar, m., ogorelec, b., novak, m. & bavec, m. (eds.): geologija slovenije. geološki zavod slovenije, ljubljana, 99–136. placer, l. (1999): contribution to the macrotectonic subdivision of the border region between southern alps and external dinarides.– geologija, 41 (1998), 223–255. rakovec, i. (1932): h geologiji ljubljane in njene okolice.– geogr. vest, 8/1–4, 38–70. ramovš, a. (1978): okamnelo življenje v jeseniškem prostoru [versteinertes leben im gebiet von jesenice – in slovenian].– teh. muzej železarne, jesenice, 81 p. ramovš, a. & kochansky-devidé, v. (1979): karbonske in permske plasti v severnih julijskih alpah [karbon und permschichten in den nördlichen julischen alpen – in slovenian].– geologija, 22/1, 21–54. ronchi, a., kustatscher, e., pittau, p. & santi, g. (2012): late carboniferous floras from italy: an overview on the main sites and historical collections.– geol. croat., 65/3, 299–322. doi: 104154/ gc.2012.20 schönlaub, h. (1985): das paläozoikum der karnischen alpen.– in: arbeitsagung der geologischen bundesanstalt 1985. geol. bundesanst., wien, 34–52. scotese, c.r. (2002): paleomap website: http://www.scotese.com sremac, j. (2012): influence of terrestrial sedimentation in pennsylvanian rocks of croatia.– geol. croat., 65/3, 273–282. doi: 104154/ gc.2012.18 stur, d. (1886): oberkarbonische pflanzenreste von bergbau reichenberg bei assling in oberkrain.– verh. geol. r.-a., wien, 15, 383–385. takšić, a. (1947): prinos poznavanju gornjokarbonske flore golice (karavanke).– geol. vjesnik, zagreb, 1, 232–240. tornquist, a. (1929): die blei-zinklagestätte der savefalten vom typus litija (littai).– berg und hüttenmann. jb., 77/1, 1–28. winkler, a. (1923): über den bau der östlichen südalpen.– mitt. geol. ges., wien, 16, 1–272. manuscript received february 01, 2012 revised manuscript accepted september 02, 2012 available online october 30, 2012 1. introduction fragments of ancient oceanic lithosphere are terrestrially exposed in an orogenic belt, due to relative coherent thrust sheets that form an ophiolite complex that is generally associated with underlying ophiolite mélange. most of the oceanic lithosphere, with a geochemical affinity highlighted by proper (normal) middle ocean ridge basalts (n-morb), was formed at the mid oceanic ridge during several tens of millions of years of spreading. the major part of the mid oceanic ridge succession has been subducted, and only a minor part has been preserved by being removed from the subducting slab, in trench sediments of the accreationary prism in front of the overriding plate. however, a significant proporab stra ct the eastern tethyan repno oceanic domain (rod), from the zagorje-mid-transdanubian shear zone, borders the meliata-maliak and dinaric-vardar oceanic realms. the domain lacks ophiolite complexes and oceanic rocks are restricted to four early callovian to late valanginian ophiolite mélange sectors integrated in the kalnik unit. previous research on ophiolitic rocks from the kalnik unit provided a detailed tectonomagmatic evolution of crust formation at different settings from the late anisian to the cretaceous. n-morb-type crust with peculiar supra-subduction signatures formed on a spreading ridge from the late carnian (~225 ma) to the late pliensbachian (~185 ma), and the first intraoceanic subduction rocks were dated as late bathonian (165 ma). the newly discovered basaltic rocks, in coherent slices with the latest bajocian-early bathonian (~169 ma) radiolarin cherts from the mt. medvednica ophiolite mélange sector, completed the late pliensbachian-late bathonian chemostratigraphic gap in the domain. the analysed unfractionated extrusive rocks lack any influence of a subduction related component, [(nb/la)n = 1.16– 1.34; th/ta = 0.99–1.05] and are akin to proper n-morb compositions [(nd/lu)n-morb ~ 1.1; (la/lu)cn = 0.82– 0.92] that were derived from a slightly depleted mantle source [εnd(t=170 ma) = +6.21 to +6.27; (87sr/86sr)i = 0.703365 to 0.703511]. the rocks are interpreted as vestiges of the middle oceanic ridge crust formed during the culmination of spreading in the rod. keywords: petrology, geochemistry, n-morb extrusives, ophiolite mélange, bajocian-bathonian, zagorjemid-transdanubian zone, mt. medvednica, croatia geologia croaticageologia croatica geologia croatica 65/3 435–446 10 figs. 3 tabs. zagreb 2012 evidence of the spreading culmination in the eastern tethyan repno oceanic domain, assessed by the petrology and geochemistry of n-morb extrusive rocks from the mt. medvednica ophiolite mélange (nw croatia)  damir slovenec1 and boško lugović2 1 croatian geological survey, sachsova 2, hr-10 000 zagreb, croatia (e-mail: damir.slovenec@hgi-cgs.hr) 2 institute of mineralogy, petrology and mineral deposits, faculty of mining, geology, and petroleum engineering, university of zagreb, pierottijeva 6, hr-10 000 zagreb, croatia (e-mail: blugovic@rgn.hr) doi: 104154/gc.2012.32 geologia croatica 65/3geologia croatica 436 tion of the youngest n-morb lithosphere related to the spreading ridge has been obducted and created an example of pristine crust of the intraoceanic upper plate, which was replaced by ongoing formation of true ssz crust derived from a depleted and metasomatized mantle wedge, that experienced a long term complex history of partial melting. consequently, the amount of proper n-morb lithologies is relatively low in the ophiolite mélange. the culminating stage of ocean spreading, represented by the youngest nmorb crust, may therefore be poorely documented in an ophiolite mélange and only a systematic petrological and geochemical study of magmatic inclusions of the mélange may provide more opportunity to characterize oceanic tectomagmatic evolution at this stage. this work provides more detailed knowledge of the tectonomagmatic evolution of an eastern tethyan oceanic domain, colloquially termed the repno oceanic domain (rod; babić et al., 2002), which borders the meliata-maliak and dinaric-vardar ocean systems. the domain lacks ophiolite complexes and ophiolitic rocks are exposed in only four separate ophiolite mélange sectors, integrated in the kalnik unit by haas et al., (2000). the various magmatic blocks and juxtaposed fragments of sedimentary rocks, vary in both age and lithology, and are mostly tectonically included within the matrix of mélange, thus obscuring their original geological setting of formation (halamić, 1998; slovenec & pamić, 2002). previous research on the magmatic blocks in the kalnik unit, provided constraints on the detailed geodynamic and tectonomagmatic evolution of the rod, based exclusively on geochemical and petrological data. the evolution commenced in the anisian by intra-continental rifting, via formation of proto-oceanic crust in the ladinian and the onset of crust formation at a spreading ridge until the middle jurassic. initial ssz crust formed in the late bathonian, with formation of infant forearc-proto-arc crust in the callovian-oxfordian, and formation of the youngest crust in a cretaceous back-arc basin (lugović et al., 2007; slovenec & lugović, 2008, 2009; slovenec et al., 2010, 2011; kiss et al., 2012; lugović et al., in rewiev). the peculiar characteristic of morb-type crust in the rod that commenced in the middle carnian and was prolonged to the late pliensbachian is its ssz geochemical flavour. the evolutionary stage of the rod that may be reflected by proper n-morb lithosphere remained unsolved by previous research. relatively rare occurrences of the relevant rocks were recently encountered only in the mt. medvednica ophiolite sector near poljanica (locus tipicus). petrological and geochemical research on these rocks and particularly on the coherent blocks composed of n-morb pillow lavas and radiolarian cherts, provided age determination of the culminating phase of spreading in the rod, thus improving knowledge of the high-resolution tectomomagmatic evolution of the domain. 2. outline of regional geology mt. medvednica along with mts. ivanščica and kalnik is located at the southwestern tip of the sw-ne trending zagorje-mid-transdanubian zone (zmtdz; pamić & tomljenović, 1998), within the triple junction zone between three complex tectonic units represented by the southerneastern alps unit, internal dinarides, and the tisia continental block (fig. 1a). the zmtdz approximately corresponds to the sava unit defined by haas et al. (2000) and comprises a 100 km wide and 400 km long area between the periadriatic-balaton lineament to the north and the zagrebzemplin lineament to the south. although the structural pattern of these intra-panonnian inselbergs is obscured by tertiary displacements and neogene sedimentary cover, a dinaride characteristic has been recognized (e.g. haas & kovács, 2001). the true dinarides which are traditionaly divided into the external (outer) and internal (inner) dinarides, stretch southeastwards from the zagreb-zemplin lineament as 700 km long tectonostratigraphic units bounded by the skutari-peć transform fault to the southeast (fig. 1a). dinaric tectonostratigraphic units extend further into the albanides and continue southwards into the hellenides. the external dinarides mainly consist of mesozoic carbonate platform that is structurally overlain by allochthonous, continentally derived units showing palaeozoic–triassic stratigraphic successions; the internal dinarides comprise several zones that regularly reflect the transition from platform sediments to the mesozoic oceanic realm, with the outermost zone sutured to the eurasian continental lithospheric plate, (see compilation in pamić et al., 2002 and robertson et al., 2009). most internal zones are dominated by ophiolite units and are sensu pamić (2002) subdivided into the central dinaridic ophiolite zone (cdoz) and more internal sava-vardar suture zone (svsz). structural and palaeomagnetic data indicate that the tectonic block comprising the medvednica, ivanščica and kalnik mts. experienced ca. 130° clock-wise rotation and eastwards escape during the oligocene-earliest miocene, (tomljenović et al., 2008) that resulted in a structural trend almost perpendicular to the nw-se dinaric trend. despite this dramatic change of trend in respect to the overall dinaric structural trend, schmid et al. (2008) included the zmtdz in the western vardar ophiolite unit, based on the similar tectonostratigraphic evolution, particularly for the ophiolitic rocks. ophiolite mélanges from the southwestern zmtdz exposed in these three mountain sectors, and possibly those in the mt. samoborska gora sector, are integrated into a combined tectonostratigraphic unit termed the kalnik unit (haas et al., 2000). the kalnik unit incorporates various ophiolitic, lithic vestiges related to the rod, that according to bortolotti & principi (2005) may represent the westernmost oceanic segment of eastern tethys. therefore, the rod is an important oceanic domain that borders the meliata-maliak oceanic segment located to the northeast and the dinaric-vardar oceanic system to the southeast. 3. geology of medvednica mt. the geographic position of the locations relevant for this work and a simplified geological map of the northwestern part of mt. medvednica are displayed in fig. 1b–c. damir slovenec and boško lugović: evidence of the spreading culmination in the eastern tethyan repno oceanic domain... geologia croatica 437 structurally, the lowermost tectonic unit of mt. medvednica consists of lower greenschist facies paraand orthometamorphic rocks represented by slate-phyllites, quarzites, marbles metasandstones and greenschists, respectively (šikić et al., 1978, 1979; basch, 1981, 1983), that correspond to the zmtdz metamorphic complex or medvednica unit (haas et al., 2000). the medvednica unit comprises a thick sedimentary succesion deposited from the silurian to the ladinian, that was metamorphosed in the lower aptian (belak et al., 1995) by emplacement of a late jurassic island-arc onto the adria continental margin (lugović et al., 2006). the medvednica unit is thrusted by an ophiolite mélange, that is, by the mt. medvednica sector of the kalnik unit. the accretionary age of the kalnik unit can be constrained from the early callovian to the late valanginian (babić et al., 2002) and represents the period of accumulation of lithostratigraphically different materials in the intraoceanic trench (slovenec et al., 2011). both units are unconformably overlain by a late cretaceous-palaeocene gosau-type sedimentary sequence, composed of clastic-carbonate and flysch sediments (šikić et al., 1979). neogene and pleistocene sedimentary sequences unconformably overlie pre-neogene basement rocks along the southern slopes of the mountain, whilst on the northwestern slopes they are tectonically superimposed. the kalnik unit in the mt. medvednica sector is characterized by block-in matrix fabric, typical for chaotic complexes from subduction-related tectonic mélanges (festa et al., 2010). the primary depositional structural features are obliterated during emplacement and incorporation of large fault-bounded olistoliths (fig. 1c), that resulted in strongly sheared pelitic-silteous continent derived matrix. however, the matrix of the ophiolite mélange does not show any metamorphic overprint after diagenetic equilibration (judik et al., 2008). the mt. medvednica ophiolite mélange incorporates fragments of various mesozoic sedimentary rocks, (grey wacke, minor shale, red and grey cherts and scarce limestones), that are randomly mixed, along with fragments of igneous plutonics (peridotite cumulates and gabbros) and extrusive basalts and mafic dyke rocks (slovenec & lugović, 2008, 2009; slovenec et al., 2010 and references). fragments of basaltic rocks are fairly dominated by magmatic compofigure 1: (a) geotectonic sketch map of alps, dinarides and hellenides showing the position of the periadriatic-sava-vardar suture zone (modified after pamić, 2000). legend: 1 – external dinarides and alps; 2 – internal units [a: central dinaride ophiolite belt (cdob); b: passive continental margin and mirdita zone]; 3 – periadriatic-sava-vardar zone; 4 – serbo-macedonian massif; 5 – pelagonide metamorphic complex; 6 – golija paleozoic zone; 7 – zagorje-mid-transdanubian zone; 8 – panonian basin. faults: bl – balaton; df – drava; pl – periadriatic; sf – sava; sp – scutari-peć; sn – sava nape; zz – zagreb-zemplin. mountains: i – ivanščica; k – kalnik; md – medvednica; sgž – samoborska gora and mts. žumberak; sd – szarvaskö-darnó. b – bódva valley; jk – jaklovce. (b) geographical location of the study area (gray shaded). (c) simplified geological map of mt. medvednica (modified after halamić, 1998). legend: 1 – neogene and pleistocene sedimentary rocks; 2 – late cretaceous-paleocene flysch including senonian carbonate breccias; 3 – ophiolite mélange with blocks of: 4 – middle triassic radiolarites, shales, limestones, pyroclastites and basalts (black fields), 5 – middle jurassic radiolarites, shales and basalts (dark gray fields), 6 – alb-cenomanian limestones and clastic rocks (shale, siltite and sandstone); 7 – lower cretaceous metamorphic complex; 8 – reverse or thrust faults; 9 – normal faults; 10 – geological contact line; 11 – sample locations: 1 = vs-113/2, vs-113a4; 2 = vh-49b; 3 = vs-94/1; 4 = vs-85/2; 5 = vh-1001/1; 6 = vs-307/1. geologia croatica 65/3geologia croatica 438 nents in this ophiolite mélange. excluding fragments of illyrian-fassanian pre-oceanic within-plate alkali basalts, all other magmatic rocks display oceanic supra-subduction affinity, i.e., are scraped from an upper plate. in mt. medvednica, the oceanic crust fragments show a wide range of geochemical signatures consistent with their geotectonic setting, but show a relatively narrow range of corresponding ages of formation (slovenec & lugović, 2009). the oldest oceanic rocks in the mt. medvednica ophiolite mélange are the latest bathonian n-morb-like basalt, related to the initial intraoceanic subduction rocks that were followed by true subduction iat-type basalts of the early oxfordian. despite age or geotectonic provenance, these morb-type or morblike lithologies show peculiar subduction related components, or, in another words, correspond to “morbs with arc-signatures” sensu shervais (2001). however, only six blocks of proper n-mor basalts were found in the poljanica area of the mt. medvednica ophiolite mélange (fig. 1c) which is a unique occurrence of this rock type in the entire kalnik unit. these hectometre large blocks consist of pillow lavas and massive extrusives (fig. 1c, locations 1, 4, 5, 6 and 2–3, respectively). pillow lavas at location 1 and location 5 form a coherent slice along with radiolarian cherts, sometimes mixed with silicified shales which were (on account of the radiolarian assemblage) dated to the latest bajocian-early bathonian (halamić et al., 1999). these extrusive rocks are the subject of this work. 4. analytical techniques minerals were analyzed at the mineralogisches institut, universität of heidelberg, using a cameca sx51 electron microprobe equipped with five wavelength-dispersive spectrometers. measurements were performed using an accelerating voltage of 15 kv, beam current of 20 na, beam size of ~ 1 µm (for feldspars 10 µm) and 10 s counting time for all elements. natural minerals, oxides and silicates were used for calibration. raw data for all analyses were corrected for matrix effects with the pap algorithm (pouchou & pichoir, 1984, 1985) implemented by cameca. formula calculations were figure 2: plot of clinopyroxene compositions in the en–wo–fs (mg2si2o6–ca2si2o6–fe2si2o6) diagram with the nomenclature fields of morimoto (1988) for n-morb volcanic rocks from the mt. medvednica ophiolite mélange. field of clinopyroxene compositions (dark gray shaded) from high-, mediumand low-ti tholeiitic ssz basalts in the mt. medvednica ophiolite mélange (slovenec & lugović, 2009) plotted for correlation constraints. table 1: selected microprobe analyses and structural formulae of clinopyroxene from the n-morb extrusive rocks in the mt. medvednica ophiolite mélange sample vs-113/2 anal. nr. 6 8 11 13 17 18 21 23 sio2 49.94 47.98 49.56 48.98 51.77 50.60 49.44 49.54 tio2 1.31 2.29 1.57 1.64 1.09 1.44 1.31 1.53 al2o3 2.55 4.26 3.13 3.68 2.06 2.11 2.93 3.11 cr2o3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.05 feo 12.69 12.56 10.12 10.65 9.58 13.90 13.73 9.97 mno 0.60 0.45 0.31 0.33 0.30 0.43 0.43 0.23 mgo 12.05 11.37 14.61 13.67 14.83 12.19 11.75 13.92 cao 19.83 20.38 19.73 20.23 20.09 19.06 19.59 20.42 na2o 0.45 0.43 0.68 0.41 0.32 0.19 0.40 0.46 total 99.42 99.72 99.73 99.59 100.04 99.92 99.65 99.23 si 1.900 1.824 1.846 1.838 1.926 1.925 1.882 1.862 ti 0.037 0.065 0.044 0.046 0.030 0.041 0.038 0.043 aliv 0.100 0.176 0.137 0.162 0.074 0.075 0.118 0.138 alvi 0.014 0.015 0.001 0.001 0.016 0.020 0.014 0.001 cr 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.001 fe3+ 0.043 0.062 0.131 0.098 0.020 0.000 0.058 0.085 fe2+ 0.360 0.338 0.184 0.236 0.278 0.442 0.379 0.229 mn 0.019 0.014 0.010 0.010 0.009 0.014 0.016 0.006 mg 0.683 0.644 0.811 0.765 0.882 0.692 0.667 0.780 ca 0.808 0.830 0.787 0.813 0.801 0.777 0.799 0.822 na 0.033 0.032 0.049 0.030 0.023 0.014 0.030 0.034 total 4.000 4.000 4.000 4.000 4.000 4.000 4.000 4.000 mg# 65.5 65.6 81.5 76.4 74.7 61.0 63.8 77.3 alvi/aliv 0.14 0.09 0.01 0.01 0.21 0.27 0.12 0.01 wo 42.21 43.96 40.93 42.30 41.48 40.37 41.64 42.76 en 35.69 34.13 42.17 39.77 42.60 35.93 34.75 40.56 fs 22.09 21.91 16.89 17.93 15.93 23.70 23.62 16.68 formulae calculated on the basis of 4 cations and 6 oxygens. mg# = 100*mg/ (mg + fe2+). damir slovenec and boško lugović: evidence of the spreading culmination in the eastern tethyan repno oceanic domain... geologia croatica 439 done by using a software package designed by hans-peter meyer from the mineralogisches institut, universität of heidelberg, germany. bulk-rock powders for chemical analyses of seven samples were obtained from rock chips free of veins and amygdales. the samples were analysed by icp for major elements, and icp-ms for all trace elements at actlab laboratories in ancaster, canada. international mafic rocks were used as standards. major element and trace element concentrations were measured with accuracy better than 1% and 5%, respectively. isotopic compositions of 2 bulk rock samples were measured in crpg in vandoeuvre, france, on a triton plus mass spectrometer. normalizing ratios of 86sr/88sr = 0.1194 and 146nd/144nd = 0.7219 were assumed. the 87sr/86sr ratio for the nbs 987 sr standard for the period of measurement was 0.710242 ± 0.000030 (2σ). the 143nd/144nd ratio for the la jolla standard was 0.5118451 ± 0.000010 (2σ). total procedural blanks were ~500 pg and ~150 pg for sr and nd, respectively. 5. petrography and mineral chemistry the analysed rocks are represented by green to red basaltic massive or amygdaloidal pillow lavas, characterized by irregular fracturing. monomineralic vesicle infillings are composed of calcite, chlorite or fine-grained quarz. near the contact with the shale, the pillows exhibit a fine-grained haematite pigmented zone with divergent-radial texture. both types of lavas are severely altered but still preserve fineto mediumgrain ophitic, or intergranular texture occassionally with minor plagioclase phenocrysts. magmatic plagioclase is replaced by albite (an0.2–3.1) and peristerite (an~8) and contains small inclusions of chlorite, aggregated sericite-pumpellyite and zoisite-group minerals. small relics of skeletal clinopyroxene are rare, usually pseudomorphosed by pycnochlorite-diabantite and epidote. fe-ti oxides (magnetite and skeletal ilmenite) are accessory minerals. such altered rocks are usually called spilite. petrographic evidence suggests the following order of crystallization: plagioclase → clinopyroxene + plagioclase ± fe-ti oxides, that is traditionally assumed as typical for volcanic rocks formed at an ocean ridge (e.g. beccaluva et al., 1980). microtextures of an alteration assemblage with prehnite, pumpellyite, chlorite and calcite indicate ocean floor metamorphism. the clinopyroxene from the poljanica rocks shows an augite composition (wo40.4–43.9en34.1–42.6fs15.93–23.7; table 1) that is significantly different compared to the clinopyroxenes from the mt. medvednica ssz volcanic rocks (fig. 2). they are characterized by a comparatively higher content of non-quadrilateral elements (fig. 3) and their ti/al ratio (0.28–0.43). the tio2 content is generally high but variable in individual grains (1.09–2.29 wt.%), whilst the range of mg# is limited to 81.5–61.0 (table 1) reflecting the lack of significant fe-enrichment in the analyzed clinopyroxenes (fig. 2). the clinopyroxene alvi/aliv ratio ≤ 0.27 suggests low pressure crystallization consistent with the observed order of crystallization. 6. bulk rock chemistry chemical compositions of the analyzed rocks are shown in table 2. high loi (up to 8.32 wt.%) combined with petrographic evidence confirm the severe alteration of the rocks that might have affected the magmatic content of certain elements. the relative mobility of elements was proven by plotting their concentration against zr as a differentiation index (not shown). large ion lithophile elements (= lile) cs, rb, k, ba and sr revealed random and selective migration caused by alteration and were consequently excluded from petrogenetic constraints. however, high field strength figure 3: (a) diagram sio2/100 – na2o – tio2 and (b) ti – aliv (simplifed after beccaluva et al., 1989) for clinopyroxene from the mt. medvednica n-morb volcanic rocks. morb – mid-ocean ridge basalts; babb – back-arc basin basalts; iat – island-arc tholeiites; bon – boninite. fields of clinopyroxene compositions (gray shaded) from high-, mediumand low-ti tholeiitic ssz basalts in the mt. medvednica ophiolite mélange (slovenec & lugović, 2009) plotted for correlation constraints. geologia croatica 65/3geologia croatica 440 elements (= hfse) ti, th, hf, nb, ta, p and y and rare earth elements (= ree) from la to lu showed magmatic cor relation and therefore were utilized as suitable tools for geoche mical and petrogenetic considerations, as previously used for analogue rocks elsewhere (e.g. pearce & norry, 1979; shervais, 1982; beccaluva et al., 1983). this also holds true for the transitional metals v, cr, mn, fe, ni and zn, though their measured concentrations are strongly dependent on the amount of related mineral phase in a rock. figure 4: ni – ti/cr diagram (beccaluva et al., 1983) for the n-morb volcanic rocks from the mt. medvednica ophiolite mélange. field (gray shaded) for high-, mediumand low-ti tholeiitic ssz basalts from the mt. medvednica ophiolite mélange (slovenec & lugović, 2009) plotted for correlation constraints. figure 5: v – ti/1000 diagram (shervais, 1982) for the n-morb volcanic rocks from the mt. medvednica ophiolite mélange. iat – island-arc tholeiites, morb – mid-ocean ridge basalts, babb – back-arc basin basalts, oib – ocean-island basalts and ab – alkali basalts. fields for high-, mediumand low-ti tholeiitic ssz basalts from the mt. medvednica ophiolite mélange (slovenec & lugović, 2009), late pliensbachian gabbros (lugović et al., in rewiev) and late carnian basalts (slovenec et al., 2011) from mt. kalnik plotted for correlation constraints. table 2: chemical analyses of n-morb extrusive rocks from the mt. medvednica ophiolite mélange. sample vs113/2 vs113a4 vh49b vs94/1 vs85/2 vh1001/1 vs307/1 rock type pb pb mb mb pb pb pb sio2 51.32 46.43 49.62 47.12 48.23 47.89 47.06 tio2 1.20 1.34 1.24 1.38 1.42 1.57 1.64 al2o3 16.68 15.67 17.46 15.02 15.94 14.96 13.78 fe2o3 total 8.32 9.05 6.84 12.43 9.21 13.05 13.88 mno 0.32 0.71 0.15 1.26 0.29 0.33 0.25 mgo 6.65 7.06 7.13 8.01 6.92 7.63 7.78 cao 5.92 6.98 7.91 4.03 6.28 5.39 5.99 na2o 4.75 3.99 4.51 3.35 3.56 3.21 2.83 k2o 0.32 0.15 0.65 0.16 0.32 0.18 0.16 p2o5 0.10 0.10 0.11 0.12 0.11 0.13 0.15 loi 3.96 8.32 3.93 6.89 6.64 5.31 5.94 total 99.54 99.80 99.55 99.77 99.92 99.65 99.46 mg# 62.9 61.1 67.9 56.5 60.7 55.3 53.6 cs 0.5 1.2 0.7 1.6 1.4 2.1 1.8 rb 12 7 12 15 11 10 9 ba 225 108 257 203 192 202 187 th 0.24 0.21 0.26 0.27 0.23 0.34 0.37 ta 0.24 0.20 0.25 0.27 0.22 0.33 0.36 nb 4.0 3.4 4.1 4.5 3.7 5.5 5.8 sr 92 101 131 105 112 101 132 zr 72 70 83 92 75 98 111 hf 2.0 1.8 2.2 2.5 1.9 2.7 3.0 y 25 24 27 31 25 34 38 sc 35 34 40 32 39 41 48 v 206 196 226 214 218 221 254 cr 575 598 497 372 524 126 187 ni 191 294 195 210 233 122 156 la 3.47 3.14 3.76 3.98 3.25 4.51 4.63 ce 9.92 8.78 10.51 11.16 9.02 12.48 12.65 pr 1.38 1.22 1.55 1.64 1.31 1.73 1.85 nd 7.24 6.67 7.89 8.99 6.98 9.20 10.28 sm 2.56 2.21 2.65 3.04 2.31 3.25 3.54 eu 0.981 0.872 1.010 1.139 0.940 1.219 1.412 gd 3.31 3.08 3.38 4.03 3.21 4.23 4.74 tb 0.59 0.55 0.62 0.73 0.59 0.79 0.92 dy 3.84 3.61 4.07 5.02 3.78 5.51 6.14 ho 0.89 0.83 0.94 1.11 0.88 1.21 1.36 er 2.55 2.40 2.79 3.39 2.62 3.58 3.89 tm 0.390 0.371 0.419 0.478 0.389 0.542 0.591 yb 2.66 2.58 2.80 3.41 2.63 3.68 3.98 lu 0.399 0.389 0.421 0.490 0.402 0.552 0.588 major elements in wt.%, trace elements in ppm. loi = loss on ignition at 1100 ºc. mb = massive basalt, pb = pillow basalt. mg# = 100*molar mgo/(mgo + feototal). damir slovenec and boško lugović: evidence of the spreading culmination in the eastern tethyan repno oceanic domain... geologia croatica 441 in the zr/tio2 vs. nb/y diagram (winchester & floyd, 1977) for classification of altered extrusives, the analysed rocks with low zr/tio2 (0.006–0.007) and nb/y (0.14–0.16) plot in the field of subalkaline, tholeiitic andesite/basalt, and in this respect they are not distinguished from the mt. medvednica ssz basalts (not shown). however, they are strongly geochemically separated in the ti/cr vs. ni diagram (fig. 4) whereas in the poljanica rocks, they plot exclusively in the field of high-ti basalts of morb affinity, whilst ssz extrusives trend from high-ti to low-ti basalts of iat and/or babb signatures. the ocean ridge affinity of the poljanica rocks is also deduced from their high ti/v ratio (32.9–42.6), that is typical for morb rocks derived from a slightly depleted mantle reservoir (fig. 5). the multi-element abundance patterns normalized to nmorb values for poljanica volcanic rocks are displayed as a spider diagram in fig. 6a. the rocks display a wide range of selective lile enrichment consistent with their polyphase alterations. the unique feature of these rocks is their smooth and flat patterns in the profile from nd to lu which range from 0.8 to 1.3 times relative to n-morb and, moreover, show a very slight hfse positive anomaly [(nb/la)n = 1.16– 1.34; (ti/gd)n = 1.00–1.16]. in that respect, six blocks of poljanica basalts represent a geochemical exception concerning the whole suite of oceanic exstrusive rocks archived in the kalnik unit (compare with slovenec et al., 2011). n-morb normalized ree patterns of analysed rocks are displayed in fig. 6b. excluding a slight la-ce enrichment, (most likely due to alteration), the ree show smooth and flat profiles in the pr-lu segment of pattern [(pr/lu)n = 1.08–1.26] at 0.8–1.4 times relative to n-morb. three out of seven samples (vs-94/1, vh-1001/1 and vs-307/1, table 1) show fractionated patterns (> 1.2 times relative to n-morb). this signature combined with a lack of negative hfse anomalies in the spider diagram (fig. 6a) show that the poljanica basalts formed at an oceanic setting far away from the influence of any subduction related source, that is, at an evolved spreading ridge centre. a slight eu anomaly (eu/eu* = 1.03–0.96) in the samples is typical for low accu mulation, or fractionation, of plagioclase, suggesting that the four unfractionated rock samples may represent near primary melts. the nd and sr isotopic compositions of two pillow basalts are shown in table 3. measured 143nd/144nd ratios are concordant in both samples (0.512975 and 0.512979) whilst the 87sr/86sr ratios show slight variations between 0.704057 and 0.704423, most likely due to different intensity of alterations. the initial εnd and sr isotopic ratios calculated for an arbitrary age of 170 ma vary from +6.21 to +6.27 and from 0.703365 to 0.703511, respectively, and plot within the mantle array in the field of recent morb close to the prema (fig. 7). figure 6: (a) n-morb normalized multielement patterns (sun & mcdonough, 1989); (b) n-morb normalized ree patterns (sun & mcdonough, 1989) for the mt. medvednica n-morb volcanic basaltic rocks. gray shaded area represent compositional field of high-, mediumand low-ti tholeiitic ssz basalt suite from the mt. medvednica ophiolite mélange (slovenec & lugović, 2009) plotted to stress their distinctive geochemical signatures. table 3: nd and sr isotope data of n-morb extrusive rocks from the mt. medvednica ophiolite mélange. sample location rock group 143nd/144nda 147sm/144nd 87sr/86sra nd(t) b 87sr/86sr(t) c age (t)* vs-113/2 1 pb; high-ti 0.512975 (8) 0.213788 0.704423 (9) +6.21 0.703511 170 ma vh-1001/1 5 pb; high-ti 0.512979 (6) 0.213589 0.704057 (10) +6.27 0.703365 170 ma location number corresponds to the locations in fig. 1c. pb = pillow basalt. a errors in brackets for nd and sr isotopic ratios are given at the 2-level. 147sm/144nd ratios calculated from the icp-ms concentrations of sm and nd following equation: 147sm/144nd = (sm/nd)*[0.53151 + 0.14252*143sm/144nd]. binitial end(t) calculated assuming iochur = 0.512638, (147sm/144nd)o chur = 0.1966, and lsm = 6.54*10–12 a–1. c initial 87sr/86sr(t) calculated using icp-ms rb and sr concentrations and assuming lrb = 1.42*10–11 a–1. *coresponding age for the initial end and initial sr isotopic ratios. geologia croatica 65/3geologia croatica 442 7. discussion and conclusions ophiolite mélanges that contain fragmented rocks similar to the lithologies of a coherent lithostratigraphic pile of an ophiolite complex, formed in an accretionary wedge in front of an overriding oceanic plate (e.g. festa et al., 2010). rock fragments derived from the overriding plate were incorporated in the accretionary wedge mainly through sedimentary processes, whilst the materials from the subducting slab were included by pealing off from a morb-type subducting slab (e.g. saccani & photiades, 2005). ophiolite mélanges are finally formed as tectonic mélanges during ophiolite emplacement, whereby various rocks from continental crust are ordinarily also included in the mélange as fault-bounded blocks. a systematic petrological and geochemical study of materials incorporated in mélanges provides opportunity for detailed reconstruction of the geodynamic evolution of an oceanic realm, or its particular segment, as has been successfully done for the repno oceanic domain of the meliata-maliac-dinaric-vardar oceanic system (see fig. 10 in slovenec et. al., 2011). this work refers to terminal jurassic spreading in the rod and will improve the overall tectonomagmatic cartoon of the domain at its culminating spreading stage. as in the other two ophiolite mélange sectors (mts. samoborska gora and kalnik) of the kalnik unit, the oldest magmatic rocks in mt. medvednica are illyrian-fassanian alkali basalts, related to the terminal phase of intracontinental rifting that prograded to opening of an ensialic back-arc basin in the rod (slovenec et al., 2011). the crustal succession formed by onset of an ocean spreading ridge is completely lacking in the mt. medvednica and samoborska gora ophiolite mélange, but was well documented in the mt. kalnik by fragments of e-morb-type proto-oceanic crust formed during the early and late ladinian, followed by middle carnian t-morb-type crust; the oldest n-morbtype crust formed in the late carnian (slovenec et al., 2011) and the youngest in the late pliensbachian (lugović et al., in rewiev), both related to an evolving oceanic spreading centre. as a rule, the n-morb-type crust show supra-subduction signatures inherited from a subducting palaeotethyan oceanic slab that diminish from late carnian to the late pliensbachian crustal rocks. it was inferred that slab break-off in the rod might already have occurred in the latest pliensbachian. the initiation and onset of intraoceanic subduction is recorded in the mt. medvednica and samoborska gora sectors by abundantly distributed late bathonian high-ti n-morb-like extrusives, and callovian mediumand low-ti iat lavas and composite fragments of ssz upper crustal sequences (slovenec & lugović, 2008; 2009; slovenec et al., 2010). however, in mt. kalnik, ophiolite mélange fragments of ssz crust are rare and marked by late bathonian medium-ti basalts and tithonian iat-type amphibole gabbro, that is by now the youngest jurassic ssz crustal lithology in the rod. such a regular chemo stratigraphic progression (whatman & stern, 2011) of late bathonian to tithonian ssz upper crustal rocks in the rod, clearly reflects progressive depletion of the mantle wedge involved in melting, influenced by enriched fluids released from the subducting plate. assuming that this first ssz crust in the rod formed in the late bathonian the most evolved or, in other words, the youngest stage of middle jurassic ocean spreading evolution of the domain remains unsolved. the stratigraphic gap of ocean crust formation arising in the rod between the late pliensbachian and the late figure 7: initial 143nd/144nd – 87sr/86sr isotope ratios diagram for mt. medvednica n-morb volcanic rocks and tholeiitic ssz basalts (gray shaded; slovenec & lugović, 2009) showing the main oceanic mantle reservoirs of zindler & hart (1986). dm – depleted mantle, bse – bulk silicate earth, emi and emi ii – enriched mantle, himu – mantle with high u/pb ratio, prema – frequently observed prevalent mantle composition. the mantle array is defined by many oceanic basalts and a bulk earth value for 87sr/86sr can be obtained from this trend. data for back-arc basin basalts – babb (gray shaded field) compiled from wilson (1989) and references therein, cousens et al. (1994) and references therein, pearce et al. (1995) and ewart et al. (1998). data for mid-ocean ridge basalts – morb (solid line) compiled from wilson (1989) and references there in and cousens et al. (1994), references therein and peate et al. (1997). data for average n-morb are from sun & mcdonough (1989). data for oceanic island arcs and active continental margins – iab (broken line) compiled from wilson (1989) and references therein, cousens et al. (1994) and references therein, pearce et al. (1995) and peate et al. (1997). damir slovenec and boško lugović: evidence of the spreading culmination in the eastern tethyan repno oceanic domain... geologia croatica 443 bathonian, is now completed by the latest bajocian-early bathonian lavas from coherent slices with radiolarian cherts near the poljanica locality (fig. 1c). these volcanic rocks are geochemically more akin to late pliensbachian isotropic n-morb-type gabbros, that were formed at a spreading ridge (lugović et al., in rewiev), than to late bathonian figure 8: discrimination diagrams for the n-morb volcanic rocks from the mt. medvednica ophiolite mélange. (a) ta/yb – th/yb diagram (pearce, 1983). s – subduction zone enrichment; c – crustal contamination; w – within-plate enrichment. n-morb and e-morb are from sun & mcdonough (1989). data for back-arc basin basalts (babb) fields (mariana, lau-tonga, oman, east scotia ridge) are from pearce et al. (1984) and leat et al. (2000). (b) th – nb/16 – hf/3 diagram (wood, 1980). a – normal mid-ocean ridge basalts (n-morb); b – enriched morb (e-morb) and within-plate tholeiites (wpt); c – alkaline within-plate basalts (awpb); d – calc-alkali basalts (cab); e – island-arc tholeiites (iat); 1 – crustal contamination; 2 – ssz ophiolites trend; 3 – morb ophiolites trend. data for back-arc basin basalts – babb (light gray shaded field) compiled from saunders & tarney (1979), weaver et al. (1979), jahn (1986), ikeda & yuasa (1989), gribble et al. (1998), leat et al. (2000). fields for high-, mediumand low-ti tholeiitic ssz basalts from the mt. medvednica ophiolite mélange (slovenec & lugović, 2009), late pliensbachian gabbros (lugović et al., in rewiev) and late carnian basalts (slovenec et al., 2011) from mt. kalnik plotted for correlation constraints. figure 9: petrogenic model for n-morb volcanic rocks from the mt. medvednica ophiolite mélange. partial melting lines: dm – depleted mantle source, pm – primitive mantle source (kostopoulos & james, 1992), oib – enriched mantle source (clague & frey, 1982). model parameters = spinel-lherzolite source (ol57–opx25,5–cpx15–sp2,5), melting proportion = ol1,21–opx8,06–cpx76,37–sp14,36, distribution coefficients are from kostopoulos & james (1992). fractional crystallization lines: initial magma = 10% melting of dm and pm mantle source, respectively, fractionated mineral assemblage = ol30–cpx40– pl30, distribution coefficients are from chen et al. (1990). field (gray shaded) for high-, mediumand low-ti tholeiitic ssz basalts from the mt. medvednica ophiolite mélange (slovenec & lugović, 2009) plotted for correlation constraints. geologia croatica 65/3geologia croatica 444 ssz high-ti n-morb-like extrusives (slovenec & lugović, 2009) (fig. 5 and 8a–b). the late pliensbachian rocks show inherited negative hfse anomalies, whilst these anomalies in the late bathonian extrusives are reestablished during intraoceanic subduction (slovenec et al., 2011). however, poljanica extrusive rocks display very slight positive hfse anomalies, which, combined with other geochemical parameters, suggest a different mantle source and comparatively peculiar geotectonic setting of formation. their normalized element concentration patterns (fig. 6a, 6b), high-ti content (fig. 4) and hosted clinopyroxene composition (fig. 3a–b) are accepted as being representative of melt generation at an n-mor setting of the eastern tethyan ophiolites (e.g. serri, 1981; beccaluva et al., 1983). these mineralogical and geochemical signatures suggest that only suboceanic mantle, unaffected by subductionrelated components, contributed to the formation of rod crust during the latest bajocian-early bathonian. this is also supported by the nd-sr isotopic composition that is strictly akin to morb (fig. 7), and corresponds to the isotopic composition of prevalent mantle composition (prema). the plot in the diagram th-yb vs. ta/yb reveals morb signatures of the analyzed rocks that reflect a mantle source ranging in composition between enriched and depleted (fig. 8a). the different mantle sources for late pliensbachian and late bathonian morbs, that are obviously contaminated by subduction-related components (mantle wedge), compared to the subduction uncontaminated latest bajocian-early bathonian spreading ridge suboceanic mantle, are best illustrated from this diagram. in figure 8b, th-hf/3-nb/16 is utilized for discrimination of geotectonic settings of mafic extrusive rocks, the poljanica basalts plot in the field of nmorb and form the trend typical of basalts from mor relatad ophiolites. the poljanica basalts are undoubtely formed at a spreading ridge, from melts derived from uncontaminated suboceanic mantle (figs. 7 and 8a). different geochemical variables were used to infer the amount of partial melts extracted from a parental mantle source (e.g. pearce, 1983). the model implemented by kostopoulos and james (1992), on relative concentrations of ree, revealed most reliable results in our case. in the la/yb vs. la diagram wherein three potential mantle sources are considered (fig. 9), analysed unfractionated rock samples plot between primitive mantle (pm) and depleted mantle (dm) sources. according to the model, the poljanica basalts are compatible with appro xi mately 13–17% partial melting of a mantle source transitional between primitive and depleted morb-type mantle. jurassic mantle peridotite of such fertile composition, typical for jurassic central dinaric ophiolite lherzolites (lugović et al., 1991; bazylev et al., 2009), was never found in the rod. in conclusion, based on geochemical and petrological data, the analysed latest bajocian-early bathonian basalts from the mt. medvednica ophiolite mélange sector of the kalnik unit, represent vestiges of the youngest jurassic proper n-morb crust formed at middle ocean ridge centre during culmination of spreading in the rod as a part of the meliata-maliak-dinaric-vardar ocean system (fig. 10). this terminal phase of spreading lasted around 20 ma, from the late pliensbachian to the early bathonian, and postdated the major phase of ridge magmatism resulting in morb-type crust with ssz signatures around 55 ma, from the late carnian to the late pliensbachian (185 ma). acknowledgments the work presented is the result of the scientific projects “mesozoic magmatic, mantle and pyroclastic rocks of northwestern croatia” (grant no. 181-1951126-1141 to da. s.) and “tectonomagmatic correlation of fragmented oceanic lithosphere in dinarides” (grant no. 195-1951126-3205 to b. l.), carried out under the support of the croatian ministry of science, education and sports. critical comments by dragan milovanović and ladislav palinkaš helped to improve the final version of the manuscript. references babić, lj., hochuli, p.a. & zupanič, j. (2002): the jurassic ophiolitic mélange in the ne dinarides: dating, internal structure and geotectonic implications.– eclogae geol. helv., 95, 263–257. basch, o. (1981): basic geological map 1:100.000. sheet ivanić grad l 33–81, inst. geol. istraž. zagreb – sav. geol. zavod, beograd. basch, o. (1983): basic geological map 1:100.000. sheet ivanić grad, explanatory notes. inst. geol. istraž. zagreb – sav. geol. zavod, beograd, 1–66 (in croatian, english summary). bazylev, b.a., popević, a., karamata, s., kononkova, n.n., simakin, s.g., olujić, j., vujnović, l. & memović, e. (2008): mantle peridotites from the dinaridic ophiolite belt and the vardar zone western belt, central balkan: a petrological comparison.– lithos, 108, 37–71. doi: 10.1016/j.lithos.2008.09.011 beccaluva, l., piccardo, g.b. & serri, g. (1980): petrology of northern apennine ophiolites and comparision with other tethyan ophiolites.– in: panayiotou, a. (ed.). proceed., int. ophiolite conf. nicosia, cyprus, 314–331. figure 10: schematic geodynamic sketch of the tectonic setting of the investigated mt. medvednica n-morb extrusive rocks in the repno oceanic domain as part of meliata-maliak-vardar oceanic system. 1 – mantle diapires, 2 – oceanic crust topped by radiolarian cherts. damir slovenec and boško lugović: evidence of the spreading culmination in the eastern tethyan repno oceanic domain... geologia croatica 445 beccaluva, l., di girolamo, p., macciotta, g. & morra, v. (1983): magma affinities and fractionation trends in opholites.– ofioliti, 8, 307–324. beccaluva, l., macciotta, g., piccardo, g.b. & zeda, o. (1989): clinopyroxene composition of ophiolite basalts as petrogenetic indicator.– chem. geol., 77, 165–182. belak, m., pamić, j., kolar-jurkovšek, t., pecskay, z. & karan, d. (1995): alpine low-grade regional metamorphic complex of mt. medvednica (northwest croatia).– in: vlahović, i., velić, i. & šparica, m. (eds.): proceed., 1st croat. geol. congr., inst. geol., zagreb, 67–70 (in croation, english summary). bortolotti, v. & principi, g. (2005): tethyan ophiolites and pangea break-up.– island arc, 14, 442–470. chen, c.y., frey, f.a. & garcia, m.o. (1990): evolution of alkalic lavas at haleakala volcano, east maui, hawaii.– contr. miner. petrol., 105, 197–218. clague, d.a. & frey, f.a. (1982): petrology and trace element geochemistry of the honolulu volcanism, oahu: implications for the oceanic mantle below hawaii.– j. petrol., 23, 447–504. cousens, b.l., allan, j.f. & gorton, m.p. (1994): subductionmodified pelagic sediments as the enrichedcomponent in back-arc basalts from the japan sea: ocean drilling program sites 797 and 794.– contrib. mineral. petrol., 117, 421–434. ewart, a., collerson, k.d., regelous, m., wendt, j.i. & niu, y. (1998): geochemical evolution within the tonga-kermadec-lau arc-back-arc system: the role of varying mantle wedge composition in space and time.– j. petrol., 39, 331–368. festa, a., pini, g.a., dilek, y. & codegone, j. (2010): mélanges and mélange-forming processes: a historical overview and new concepts.– international geology review, ifirst article, 1–66. doi: 10.1080/00206810903557704 haas, j. & kovács, s. (2001): the dinaridic-alpine connection – as seen from hungary.– acta geol. hungarica, 44, 345–362. haas, j., mioč, p., pamić, j., tomljenović, b., árkai, p., bérczi-makk, a., koroknai, b., kovács, s. & r.-felgenhauer, e. (2000): complex structural pattern of the alpinedinaridic pannonian triple junction.– int. j. earth sci., 89, 377–389. halamić, j. (1998): litostratigrafska kategorizacija jurskih i krednih sedimenata s ofiolitima medvednice, kalnika i ivanščice [lithostratigraphy of jurassic and cretaceous sediments with ophiolites from the mts. medvednica, kalnik and ivanščica – in croatian, with english abstract]. phd thesis, faculty of science, university of zagreb, zagreb, 188 p. halamić, j., goričan, š., slovenec, da. & kolar-jurkovšek, t. (1999): middle jurassic radiolarite-clastic succession from the medvednica mt. (nw croatia).– geol. croat., 52, 29–57. ikeda, y. & yuasa, m. (1989): volcanism in nascent back-arc basin behind the shichito ridge and adjecent areas in the izu-ogaswara arc, northwest pacific.– contrib. mineral. petrol., 101, 377–393. jahn, b. (1986): mid-ocean ridge or marginal basin origin of the east taiwan ophiolite: chemical and isotopic evidence.– contrib. mineral. petrol., 92, 194–206. judik, k., rantitsch, g., rainer, t.m., arkai, p. & tomljenović, b. (2008): alpine metamorphism of organic matter in metasedimentary rocks from mt. medvednica (croatia).– swiss j. geosci., 101, 605–616. doi: 10.1007/s00015-008-1303-z kiss, g., molnár, f., palinkaš, l., kovács, s., hrvatović, h. (2012): correlation of triassic advanced rifting-related neotethyan submarine basaltic volcanism of the darnó unit (ne-hungary) with some dinaridic and hellenidic occurrences on the basis of volcanological, fluid-rock interaction, and geochemical characteristics.– int. j. earth sci., 101, 1503–1521. doi: 10.007/s00531-0110706-7 kostopoulos, d.k. & james, s.d. (1992): parameterization of the melting regime of the shallow upper mantle and the effects of variable lithospheric stretching on mantle modal stratification and trace element concentrations in magmas.– j. petrol., 33, 665–691. leat, p.t., livermore, r.a., millar, i.l. & pearce, j.a. (2000): magma supplay in back-arc spreding centre segment e2, east scotia ridge.– j. petrol., 41, 845–866. lugović, b., alther, r., raczek, i., hofmann, a.w. & majer, v. (1991): geochemistry of peridotites and mafic igneous rocks from the central dinaric ophiolite belt, yugoslavia.– contrib. mineral. petrol., 106, 201–216. lugović, b., šegvić, b. & altherr, r. (2006): petrology and tectonic significance of greenschists from the medvednica mts. (sava unit, nw croatia).– ofioliti, 31, 39–50. lugović, b., slovenec, da., halamić, j. & altherr, r. (2007): petrology, geochemistry and geotectonic affinity of the mesozoic ultramafic rocks from the southwesternmost midtransdanubian zone in croatia.– geol. carpath., 58, 511–530. lugović, b., slovenec, da., schuster, r., schwarz, w.h. & horvat, m. (2012): petrology, geochemistry and geochronology of gabbroic olistoliths from the ophiolite mélanges in nw dinaric-vardar ophiolite zone (croatia): vestiges of spreading, islandarc initiation and back-arc marginal basin magmatism in repno oceanic domain.– int. j. earth sci., (in rewiev). morimoto, n. (1988): nomenclature of pyroxenes.– schweiz. mineral. petrolog. mitt., 68, 95–111. pamić, j. (2000): the periadriatic-sava-vardar suture zone.– in: vlahović, i. & biondić, r. (eds.): proceed. 2nd croat. geol. congr., inst. geol., zagreb, 333–337. pamić, j. (2002): the sava-vardar zone of the dinarides and hellenides versus the vardar ocean.– eclogae geol. helv., 95, 99–113. pamić, j. & tomljenović, b. (1998): basic geological data on the croatian part of the mid-transdanubian zone as exemplified by mt. medvednica located along the zagreb-zemplen fault zone.– acta geol. hungarica, 41, 389–400. pamić, j., tomljenović, b. & balen, d. (2002): geodynamic and petrogenetic evolution of alpine ophiolites from the central and nw dinarides: an overview.– lithos, 65, 113–142. pearce, j.a. (1983): role of the sub-continental lithosphere in magma genesis at active continental margins.– in: hawkesworth, c.j. & norry, m.j. (eds.): continental basalts and mantle xenoliths. shiva, nantwich, 230–249. pearce, j.a. & norry, m.j. (1979): petrogenetic implications of ti, zr, y, and nb variations in volcanic rocks.– contrib. mineral. petrol., 69, 33–47. pearce, j.a., lippard, s.j. & roberts, s. (1984): characteristics and tectonic significance of supra-subduction zone ophiolites.– in: kokelaar, b.p. & howells, m.f. (eds.): marginal basin. geology, geol. soc. london spec. publ., 16, 17–94. pearce, j.a., baker, p.e., harvey, p.k. & luff, i.w. (1995): geochemical evidence for subduction flukses, mantle melting for fractional crystalization beneath the south sandwich island arc.– j. petrol., 36, 1073–1109. peate, d.w., pearce, j.a., hawkesworth, c.j., colley, h., edwards, m.h. & hirose, k. (1997): geochemical variations in vanuatu arc lavas: the role of subducted material and a variable mantle wedge composition.– j. petrol., 38, 1331–1358. pouchou, j.l. & pichoir, f. (1984): a new model for quantitative analyses. i. application to the analysis of homogeneous samples.– la recherche aérospatiale, 3, 13–38. pouchou, j.l. & pichoir, f. (1985): “pap” (φ-ρ-z) correction procedure for improved quantitative microanalysis.– in: armstrong, j.t. (ed.): microbeam analysis, san francisco press, 104–106. robertson, a., karamata, s. & šarić, k. (2009): overwiew of ophiolites and related units in the late palaeozoic-early cenozoic magmatic and tectonic development of tethys in the northern geologia croatica 65/3geologia croatica 446 part of the balkan region.– lithos, 108, 1–36. doi: 10.1016/j. lithos.2008.09.007 saccani, e. & photiades, a. (2005): petrogenesis and tectonomagmatic significance of volcanic and subvolcanic rocks in the albanide-hellenide ophiolitic mélanges.– the island arc, 14, 494–516. saunders, a.d. & tarney, j. (1979): the geochemistry of basalts from a back-arc spreading center in the east scotia sea.– geochim. cosmochim. acta, 43, 555–572. schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., scheffer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine-carpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss j. geosci., 101, 139–183. doi: 10.1007/s00015-008-1247-3 serri, s. (1981): the petrochemistry of ophiolitic gabbro-complexes: a key for classification of ophiolites to low-ti and high-ti types.– earth planet. sci. lett., 52, 203–212. shervais, j.w. (1982): ti-v plots and petrogenesis of modern and ophiolitic lavas.– earth planet. sci. lett., 59, 101–118. shervais, j.w. (2001): birth, dead, and resurrection: the life cycle of supra-subduction zone ophiolites.– geochemistry, geophysics, geosciences, v. 2 [2000gc000080]. slovenec, da. & pamić, j. (2002): the vardar zone ophiolites of mt. medvednica located along the zagreb-zemplin line (nw croatia).– geol. carpath., 53, 53–59. slovenec, da. & lugović, b. (2008): amphibole gabbroic rocks from the mt. medvednica ophiolite mélange (nw croatia): geochemistry and tectonic setting.– geol. carpath., 59, 277–293. slovenec, da. & lugović, b. (2009): geochemistry and tectonomagmatic affinity of extrusive and dyke rocks from the ophiolite mélange in the sw zagorje-mid-transdanubian zone (mt. medvednica, croatia).– ofioliti, 34, 63–80. slovenec, da., lugović, b. & vlahović, i. (2010): geochemistry, petrology and tectonomagmatic significance of basaltic rocks from the ophiolite mélange at the nw external-internal dinarides junction (croatia).– geol. carpath., 61, 273–294. slovenec, da., lugović, b., meyer, h.p. & garapićšiftar, g. (2011): a tectono-magmatic correlation of basaltic rocks from ophiolite mélanges at the north-eastern tip of the savavardar suture zone, northern croatia, constrained by geochemistry and petrology.– ofioliti, 36, 77–100. doi: 10.2478/v10096-0100016-1 sun, s.s. & mcdonough, w.f. (1989): chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes.– in: saunders, a.d. & norry, m.j. (eds.). magmatism in ocean basins.– geol. soc. london. spec. publ., 42, 313–345. šikić, k., basch, o. & šimunić, an. (1978): basic geological map 1:100.000. sheet zagreb, inst. geol. istraž. zagreb – sav. geol. zavod, beograd. šikić, k., basch, o. & šimunić, an. (1979): basic geological map 1:100.000. sheet zagreb, explanatory notes. inst. geol. istraž. zagreb – sav. geol. zavod, beograd, 1–81 (in croatian, english summary). taylor, s.r. & mclennan, s.m. (1985): the continental crust: its composition and evolution.– blackwell, oxford, 312 p. tomljenović, b., csontos, l., márton, e. & márton, p. (2008): tectonic evolution of the northwestern internal dinarides as constrained by structures and rotation of medvednica mountains, north croatia.– geol. soc. london, spec. publ., 298, 145–167. whatman, s.a. & stern, r.j. (2011): the ‘subduction initiation rule’: a key for linking ophiolites, intra-oceanic forearcs, and subduction initiation.– contrib. mineral. petrol., 162, 1031–1045. doi: 10.1007/s00410-011-0638-z weaver, d.s., saunders, a.d., pankhurst, r.j. & tarney, j. (1979): a geochemical tudy of magmatism associated with the initial stages of back-arc spreading.– contrib. mineral. petrol., 68, 151–169. wilson, m. (1989): igneous petrogenesis.– unwin hyman ltd., london. 465 p. winchester, j.a. & floyd, p.a. (1977): geochemical discrimination of different magma series and their differentiation products using immobile elements.– chem. geol., 20, 325–343. wood, d.a. (1980): the application of a th-hf-ta diagram to problems of tectonomagmatic classification and establishing the nature of crustal contamination of basaltic lavas of the british tertiary volcanic province.– earth planet. sci. lett., 50, 11–30. zindler, a. & hart, s.r. (1986): chemical geodynamics. ann. rev.– earth planet. sci., 14, 439–571. manuscript received may 29, 2012 revised manuscript accepted september 10, 2012 available online october 30, 2012 ab stra ct clypeina lagustensis n. sp. has been found in the lower tithonian deposits of lastovo island (dalmatia, croatia). it is visually similar, obviously related and in some sections appears almost identical, to clypeina jurassica favre, from which it differs by visible swellings and thinning of the central cavity, more pronounced distance between the neighbouring whorls of fertile laterals, and in the shape and structure of the interverticillate thallus parts, characterized by having well developed, hairy, sterile laterals. these, after emerging from the exit pore, divide into several bundles which form a common tuft with a calcareous envelope in the proximal part. keywords: calcareous algae (dasycladales), taxonomy, stratigraphy, jurassic (tithonian), lastovo island, croatia  geologia croatica 67/2 75–86 1 fig. 1 tab. 6 pls. zagreb 2014 geologia croaticageologia croatica clypeina lagustensis n. sp., a new calcareous alga from the lower tithonian of lastovo island (croatia)  branko sokač1, tonći grgasović1 and antun husinec2 1 croatian geological survey, sachsova 2, hr-1000 zagreb, croatia; (tgrgasovic@hgi-cgs.hr) 2 department of geology, st. lawrence university, canton, ny 13617, usa; (ahusinec@stlawu.edu) doi: 10.4154/gc.2014.06 1. introduction in the preparation for the new lithostratigaphic map of cro atia, the croatian geological survey investigated several regions within the dinarides, including the insular belt, in order to establish lithostratigraphic units suitable for correlation within the broader dinaridic area. on lastovo island, these investigations were carried out by husinec and others and included a detailed study of several characteristic crosssections with systematic sampling. the collected samples were analysed from different aspects, including micropalaeontological analysis. particular attention was paid to sample lsl-43, due to the abundant fragments and sections reminiscent of the well-known species clypeina jurassica favre. among numerous transverse and slightly oblique sections of fertile whorls, several longitudinal, longitudinal-oblique, and tangential sections were noticed, which exhibited characteristic features that differed from what so far seemed to be indicative of c. jurassica. these included the morphology and structure of the thallus, as well as the values of some biometric parameters, which, in some earlier descriptions, seemed to be taken in variously oriented sections and, consequently, were ill-suited for comparisons. the reason for this seems to be the fact, that c. jurassica was both established (favre & richard, 1927) and subsequently determined by numerous authors, mostly involving transverse and oblique sections cutting one or at most a few (2-3) disks (baskets) of fertile laterals, thus making it impossible to gain a complete insight into the thallus morphology and reliable values for most of the biometric parameters. this was previously noticed by remane (1969), who, in his detailed morpho logical and statistical analysis of some biometric pa rameters of c. jurassica, (based upon type material and supplemented by abundant material from other localities), commented on the validity and usefulness of individual bio metric parameters, which are mutually dependent on the type and the position of sectioning. in his analysis, remane (1969) restricts himself to the values of outer thallus diameter (d), inner diameter (d), number of laterals per whorl (w), distal diameter (in horizontal and vertical plane of geologia croatica 67/2geologia croatica 76 section) of single laterals (p), and (very few) distance be tween consecutive whorls (h). he then analysed the ob served difference in particular parameters from several as pects: position (inclinations) of the plane of section with regard to the whorl position, larger or smaller steepness of laterals, thallus curvature, possible post mortem compression, ecological conditioning, etc. he mentioned, in passing, the existence of slight, irregular bulges between the fertile whorls, visible in his drawings (fig. 11 b, c; fig. 29 c, d, e, f), as a possible consequence of post mortem compression, therefore denying any significance to that feature and thus omitting it completely from the concluding diagnosis. based on his analysis, he also rejects c. inopinata favre (1932) and c. minor kerčmar (1962) as independent species, because their biometric parameters fall within the variation range stated for c. jurassica.in discussing c. jurassica, elliott (1968) interpreted the variability and differences between sections from different localities as being due to local ecological circumstances, and, besides, mentioned some biometric parameters. he thought that c. inopinata, not copiously represented in his middle east material, may be a successor to c. jurassica. at the same time, radoičić (1969) presented illustrations of c. inopinata as belonging to sections with smaller biometric parameters (d, d, w), but still falling within the range of c. jurassica, and some slight differences in the shape of the disks (baskets) of fertile laterals and their distal endings. these differences, being due to the varying inclination of laterals and the position (inclination) of the sections, are neither sufficient nor adequately con vincing for distinguishing c. inopinata from c. jurassica. granier (1986), referring to the analytical study of re mane (1969), was of the opinion that c. inopinata shows a clear synonymy with c. jurassica. the same opinion is put forward by bassoullet et al. (1978) and granier & delloffre (1992), whereas radoičić (1969) presented new data on the structure of c. jurassica and c. inopinata, regarding the sterile laterals in the interverticillate portions of the thallus, being preserved (and visible) only in their proximal parts as little shallow cups. these laterals, too, are arranged into rows (whorls) between fertile whorls, and are ascribed to both species: c. jurassica having 3-4 rows, c. inopinata 5-6 rows. this feature, however, is not clearly visible in radoičić’s (1969) sections for c. jurassica (fig. 6 a, b) and c. inopinata (fig. 6 c-d; figs. 7, 8; fig. 9 a, b, c?, d) and thus they should be, according to this interpretation, considered synonymous, the validity of c. ino pinata remaining, so far, questionable. thus, in this case, the newly observed characteristics regarding the thallus structure have been simultaneously ascribed to a questionable species (c. inopinata) and to c. jurassica, in which, however, the existence of such type of sterile laterals has not yet been undoubtedly proven. this opens the possibility for a third, as yet, unidentified, species. granier (1986, fig. 10) supplemented the graphic interpretation of remane (1969, fig. 23) with his vision of the shape and position of sterile laterals, and thus, however hypothetically, gave the example of a possibly different interpretation. in conclusion, according to the present state of availability of published material and presented opinions regarding the validity of c. inopinata, we agree with remane’s (1969) opinion, accepting also comments and the opinions of schlagintweit, dieni & radoičić (2009) regarding the conservation of the already well-established species-specific name clypeina jurassica favre. this short, partly reduced, review, of the earlier studies, opinions, supplements, and (taxonomically often confused) interpretations, including their deficiencies, was deemed necessary as a preliminary introduction to our further considerations, better understanding, and legitimacy for establishing an independent taxon for a new form, in spite of its visual similarity with c. jurassica, but nevertheless displaying newly observed characteristics. these include: thallus morphology and its structure in the interverticillate portions, large range of h value, and visibly well developed sterile latfigure 1: geographic position of the type locality of clypeina lagustensis n. sp. (lastovo island, croatia). sokač et al.: clypeina lagustensis n. sp., a new calcareous alga from the lower tithonian of lastovo island (croatia) geologia croatica 77 erals of specific shape. in contrast, it’s incontestable affinity with c. jurassica, as shown in almost visual identity in some, similarly oriented, sections of fertile whorl laterals, intracellular calcification, open distal ends of fertile laterals, and identical values for some biometric parameters in their overlapping intervals within their overall ranges leads to the bewildering fact that this form cannot be, always and in all sections, clearly and reliably distinguished from c. jurassica. therefore we hesitated as to which taxonomic category this form should be assigned; should it be considered as a case of heteromorphism, variation, subspecies, or be separated as a new taxon? taking all its specific features together, as a set of differences with regard to c. jurassica, and accepting the possibility that by gradual acquisition of new, more or less pronounced, features, species become the origin for another species, we decided to put this form in the species rank as clypeina lagustensis n. sp. 2. geological setting the lastovo archipelago is composed of the homonymous island and 45 smaller islands and islets located in the southern croatian part of the adriatic sea. the backbone of the archipelago consists of upper jurassic to mid cretaceous shallow-water limestone, dolomite, and intraformational breccia. it’s geological makeup has been described by jagačić (1970), korolija & borović (1975), and korolija & al. (1977). recently, husinec & read (2006, 2007) described in detail the microfacies, sequence stratigraphic framework and chemostratigraphy of the late jurassic tithonian sequence. the oldest strata outcropping on the island are late jurassic, oxfordian in age, and composed of predominantly thick-bedded to massive subtidal mudstone and wackestone with benthic foraminifera and fragments of gastropods and echinoids. these formed in quiet lagoon settings below the zone of frequent wave reworking. local bioherms indicate the presence of patch reefs that were colonized by corals and algae, while rare ooid grainstones suggest that shoals were of very limited extent (jagačić, 1970; korolija & borović, 1975; korolija & al., 1977). the overlying kimmeridgian-lower tithonian sequence is composed of the following facies (from deepest to shallowest): dasycladoncoid mudstone-wackestone-floatstone (deeper lagoon), skeletal-peloid wackestone-packstone (shallow lagoon), intraclast-peloid packstone and grainstone (shoal-water), and barren lime mudstone (restricted lagoon). these facies typically form 0.7-to-4.5-m-thick shallowing upward parasequences capped by unfossiliferous lime mudstone (husinec & read, 2007). the bulk of the upper tithonian is oolitic, consisting of thinner, 1-3-m-thick parasequences composed of basal transgressive oolite, overlain by skeletal mudstone-wackestone (rare), intraclast-peloid packstonegrainstone (common), regressive oolite (rare), unfossiliferous mudstone, and most are capped by fenestral grainy and muddy carbonates. the most distinctive features of the upper tithonian sequence are dark-grey oolitic units with oversized ooids with primary calcite fabrics that were previously ta bl e 1: c om pa ris on o f b io m et ric p ar am et er v al ue s b y di ffe re nt a ut ho rs fo r c ly pe in a ju ra ss ic a fa vr e, c . in op in at a fa vr e, a nd c . la gu st en sis n . s p. s ym bo ls : l = m ax im um o bs er ve d le ng th ; d = o ut er d ia m et er a t t he le ve l of w ho rls ; d = in ne r d ia m et er , a pp ro xi m at el y at th e le ve l o f w ho rls ; d ’ = o ut er st em d ia m et er b et w ee n fe rt ile w ho rls ; d ’ = in ne r s te m d ia m et er b et w ee n w ho rls ; h = d is ta nc e be tw ee n ne ig hb ou rin g fe rt ile w ho rls ; p p = di am et er o f f er til e la te ra l s ta lk ; p d = di st al d ia m et er in v er tic al se ct io n; l = le ng th o f f er til e la te ra l; w = n um be r o f f er til e la te ra ls p er w ho rl; α = d ip o f l at er al s f ro m h or iz on ta l p la ne ; f . = fe rt ile la te ra l; st . = st er ile la te ra l; ho r. = ho riz on ta l s ec tio n; v er t. = ve rt ic al se ct io n. l d d d/ d d ’ d’ d’ /d ’ h pp pd l w α fa vr e 19 27 c . ju ra ss ic a 1. 45 -2 .2 5 0. 33 -0 .5 1 ve rt . 0 .3 7 11 -1 3 fa vr e 19 32 c . in op in at a up to 1 .7 0. 18 -0 .4 0 12 -1 9 ro d a 1 96 5 c. ju ra ss ic a 1. 37 -2 .0 5 0. 34 -0 .5 3 0. 27 -0 .2 8 ho r. 0. 28 -0 .4 6 11 -1 5 el li o t 19 68 c . ju ra ss ic a 2. 5 up to 0 .5 0. 05 0. 30 -0 .3 9 up to 2 4 ra d o ič ić 1 96 9 c. ju ra ss ic a 0. 80 -2 .2 8 0. 19 -0 .8 0 822 ra d o ič ić 1 96 9 c. in op in at a 0. 60 -1 .6 0. 15 -0 .4 0 817 re m a n e 19 69 c. ju ra ss ic a ty pe lo ca lit y ot he r l oc al iti es 0. 52 -3 .4 4 0. 36 -2 .5 3 0. 08 -0 .5 9 0. 07 -0 .6 8 0. 17 -0 .5 1 0. 22 -0 .4 7 ho r. 0. 15 -0 .4 8 0. 18 -0 .4 7 520 521 g ra n ie r 19 86 c . ju ra ss ic a 0. 54 -2 .1 0 0. 19 -0 .6 3 f. 0 .3 00. 40 st . 0 .0 5 0. 23 -0 .3 5 0. 17 -0 .9 0 816 th is p ap er c . ju ra ss ic a 1. 20 -3 .1 0 0. 30 -0 .8 2 0. 45 -0 .6 8 0. 08 -0 .2 0 0. 28 -0 .7 2 0. 40 -1 .3 2 821 up to 3 0° cl yp ei na la gu st ea sis n . s p. 8. 87 0. 62 -2 .0 8 0. 16 -0 .4 0 0. 12 50. 27 7 0. 40 -1 .2 4 0. 20 -0 .5 8 0. 31 30. 82 5 0. 30 -2 .1 4 0. 03 -0 .1 0 0. 20 -0 .5 8 0. 30 -0 .9 6 616 035 ° re m ar k: t he v al ue o f t he p ar am et er d d ep en ds d ire ct ly o n th e st at e (d eg re e) o f p re se rv at io n of th e ca lc ite fi lm e nv el op in g th e tu ft s o f s te ril e la te ra ls. t he c om pa ris on o f i nd iv id ua l b io m et ric p ar am et er s m en tio ne d by d iff er en t au th or s i s n ot re lia bl e, b ec au se th e qu ot ed v al ue s, de si gn at ed b y th e sa m e sy m bo l, ha ve b ee n m ea su re d in d iff er en tly p os iti on ed se ct io ns . geologia croatica 67/2geologia croatica 78 termed „vadoids” by tišljar (1985). however, based on their striking resemblance to modern low-energy lake and marginal-marine pond ooids, and their common position at the base of parasequences, husinec & read (2006) reinterpreted these as having formed predominantly during initial inundation of supratidal flats, along the shores of shallow hypersaline ponds and restricted lagoons of the platform interior. the long-term shallowing continued towards the end of the jurassic, as evident by the predominance of fenestral limestones, and culminated in platform exposure at the tithonian-berriasian transition, as evidenced by several subaerial exposure breccia interbeds with lime clasts floating in reddish to greenish clays, desiccation features and erosional truncation surfaces. the overlying lower cretaceous berriasian sequence is composed of pale to almost white ske letal mudstone with calcareous algae and fragments of bivalves and gastropods; it is commonly burrowed and has fenestral fabrics. less common are peloid-intraclast packstones and grainstones. the youngest carbonate platform deposits on the island are separated from the older succession by a fault that runs along the northern shore of the island; these are predominantly skeletal mudstone and wacke-packstones of probably upper hauterivian-lower barremian age, as suggested by sparse occurrences of the alga clypeina? solkani conrad & radoičić. the younger mesozoic (albian-cenomanian) strata do not outcrop on the island, but make up the smaller islands and islets westwards towards mljet island. the youngest deposits on the island are aeolian quaternary sands that occur as patchy outcrops of very limited extent in the eastern part of the island. 3. systematic palaeontology clypeina lagustensis n. sp. pls. i-ii; pl. iii, figs. 3, 6; pls. iv-vi ?1966 clypeina jurassica favre – radoičić, pl. cxviii, fig. 1. 1969 clypeina inopinata favre – radoičić, p. 75-81, fig.6 a-d (pars), fig.9 (a-b, c?, d), fig. 10. ?1997 clypeina jurassica favre – de castro, pl. 19 (pars), pl. 20, figs.2, 5-6. origin of the name: after the latin name (lagusta) for the lastovo island. type locality: beds exposed along the road leading northward from the skrivena luka cove to the lastovo village, about 450 m off the coast (fig. 1). gps readings: x = 6409212, y = 4734003; coordinates: 42ᵒ44’40.8’’n, 16ᵒ53’27’’e. type beds: lower tithonian, light brown, thinto thickbedded wackestone to packstone, composed of peloids and skeletal fragments of dasyclad algae, benthic foraminifera (small ataxophragmiids), oncoids, and sparse intraclasts. beds with c. lagustensis n. sp. occur within the deposits situated between the transitional kimmeridgian-tithonian levels, defined by a rich fossil assemblage including: pseudocly­ peina distomenesis barattolo & carras, parurgonina caelinensis cuvillier et al., the first occurrence of cly­ peina sp. and salpingoporella annulata carozzi in the base, and the first occurrence of campbelliella striata carozzi, frequently accompanied by c. jurassica favre, in the immediately overlying beds. passing upwards, hum­ iella sardiniensis (ott & flaviani) sporadically occurs; in the top part, there are sparse clypeina catinula carozzi and oternstella lemmensis (bernier). this defines the stratigraphic position of the algal-bearing beds on the type locality within the range of the lower tithonian. holotype: longitudinal section in the thin-section lsl43/27, figured in pl. i, fig.2. isotypes are represented by variously oriented sections, figured in pls. i-ii; iii, figs. 3, 6; iv-vi. for the time being, the complete material is stored in the sokač collection and will be handed over to the archives of the croatian museum of natural history, zagreb. diagnosis: cylindrical thallus bears pronounced separated whorls of fertile laterals and is characterized by regularly spaced constrictions of the central cavity. fertile laterals are connected to the central stem by a short stalk, often bent downwards. going outwards, fertile laterals gradually and evenly widen to about the mid-point of their length, after which they broaden abruptly, slightly bending downwards. between the disks (or baskets) of fertile whorls, the stem bears sterile laterals, with exit pores that seem to be arranged (at least in deep tangential sections) into more or less regular rows (whorls?). going out from their exit pores, the hairy sterile laterals divide into several bundles which form tufts with a calcified envelope in their proximal parts, resembling shallow cups. description: the calcareous skeleton is generally cylindrical. the swellings and constrictions of the central cavity, alternating at regular intervals, results in an apparent, more or less visible segmentation. the stem broadens between the fertile laterals and becomes narrower at the levels with whorls. immediately above the fertile whorls, the stem is at its narrowest. between the less distant whorls, the swelling of the stem assumes a barrel-like shape (pl. i, fig.4; pl. ii, fig 3; pl. iv, figs. 3, 5), whereas between the more distantly arranged whorls, the stem becomes cylindrically elongated (pl. i, fig. 5; pl. ii, fig.2; pl. iii, fig. 6; pl. iv, fig. 4). quite frequently, the thallus is outlined by a well-marked, dark, almost black, micritic zone; this is due to a muddy substance being infiltrated into the space of distally non-calcified, densely arranged, and probably mutually intertwining sterile laterals – hairs (pl. i, figs. 3–4, 6; pl. ii, figs. 1, 4). fertile laterals, within the calcified envelope, of the phloiophorous type, open at their outer ends, laterally pressed against one another, are arranged into variously spaced whorls. the distance between neighbouring whorls (h) is one of the main distinguishing characteristics of the new species; the average value varying from 0.70 to 1.35 mm, quite often reaching 1.50 mm, the maximum observed value being 2.14 mm. laterals are connected to the central stem by a short stalk (pl. i, fig. 5 arrow; pl. ii, fig. 2, pl. iv, fig. 5 arrow). the stalks are often inclined downwards, sometimes being bent in a knee-like fashion (pl. i, fig. 6; pl. iv, fig. 7). going outwards, and after escaping from the short stalk, fertile laterals widen quite uniformly up to half their length; then they sokač et al.: clypeina lagustensis n. sp., a new calcareous alga from the lower tithonian of lastovo island (croatia) geologia croatica 79 abruptly broaden distally, assuming the shape of a broad funnel (pl. iii, fig. 5; pl. iv, figs. 3, 5), which by their outer end bends downwards, thus decreasing the thickness of the calcified wall (pl. iv, figs. 3, 5; pl. v, fig. 3). being open at their outer ends, the pronounced widened laterals of neighbouring whorls touch distally, being separated only by a poorly calcified micritic primary membrane. due to reduced calcification and their being open at the distal ends, these parts of the laterals are, as a rule, erased (eroded), their square-like shape being observable only in extremely rare random tangential sections, and also showing an insufficiently clear alternating arrangement of laterals in neighbouring whorls (pl. v, fig. 5). the inclination of fertile laterals varies: from being most frequently sub-horizontal (pl. i. fig. 5; pl. iii, fig. 3) to being slightly directed upwards (pl. i, fig. 2; pl. iii, fig. 6), or being proximally obliquely directed upwards and distally bent downwards (pl. v, fig. 3). depending on the angle of inclination, fertile laterals of the same whorl, being laterally pressed close to each other, form a concave disk or, to say it more figuratively, a shallow or slightly deeper bowl. the thallus stem between fertile whorls has a very thin calcified wall (pl. i, figs. 1, 5; pl. ii, fig. 2; pl. iv, figs. 2, 4) and is covered by the exit pores of sterile laterals (pl. i, fig. 3; pl. iv, fig. 6; pl. v, fig. 7). in deep tangential section, these pores, indistinctly separated from one another, are visible as dark, dense, more or less regular rows, thus suggesting their arrangement in whorls (pl. v, fig. 7; pl. vi, fig. 3). leaving the pores, a group of hairs is divided into several (2-?5) bundles (pl. v, figs. 6, 8, 10 arrow; pl. vi, figs. 1, 5 arrow) which form a common tuft, enveloped, in its proximal part, by a calcite sheath (pl. v, fig. 8; pl. vi, figs. 4, 5 arrow). the tuft’s envelopes are visible near the thallus stem, in vertical and oblique sections, as small, irregular cups or small, shallow bowls (pl. ii, fig 1; pl. iii, fig. 6; pl. v, fig. 1; pl. vi, fig. 4). more distantly of the stem, their sections become oval, elongated, mostly irregular, deformed in appearance, and not clearly separated from one another (pl. v, figs. 1, 8; pl. vi, fig. 5). in most sections, sterile laterals are fully micritic, thus appearing in transverse sections in the form of a dark ring with variable diameter (pl. v, fig. 9; pl. vi, fig. 7 arrow). in rare cases, sterile laterals are calcified with visible, chaotically arranged, tuft’s envelopes (pl. vi, fig. 2). variability of the envelopes’ shapes and diameters depends on the number of bundles in them and the different cutting planes with regard to their direction of growth. the tufts (i.e., their calcitic envelopes) can be perpendicular to the longitudinal thallus growth axis or obliquely inclined either upwards or downwards, even in the same specimen (pl. v, fig. 1), thus indicating their mutual growing through each other, resulting in their irregular, chaotic arrangement. distally, calcification of tufts is lacking. the fine-grained, muddy substance of the surrounding sediment is infiltrated into, and kept within, the dense mass of hairs and thus post mortem marks the hairs and their extent towards the terminations of fertile laterals; or even outside, it is marked by visible, dark, almost black zone of micritic sediment (pl. i, fig. 4; pl. ii, figs. 1, 6). similarities and differences: clypeina lagustensis n. sp. is related, similar, and in some sections appearing almost identical, to c. jurassica favre. the similarity includes the general thallus shape, the morphology and arrangement of fertile laterals and their whorls, the intracellular calcification of fertile laterals, the existence of sterile laterals in interverticillate stem parts (i.e., between the whorls of fertile laterals), and the values of some of the biometric parameters. these, though falling within the range of c. jurassica favre established so far, cluster around smaller values for clypeina lagustensis n. sp. these similarities prevent the clear and unambiguous distinction of the two species, in some cases and in all similarly oriented sections. this refers particularly to transverse and oblique sections cutting through the outer parts of the fertile whorls. however, the differences are clearly brought out in longitudinal and oblique-longitudinal sections, in which the regularly alternating, swellings and constrictions of the central cavity in c. lagustensis, are clearly visible and always present. in c. jurassica, this feature is either completely absent (pl. iii, figs. 1-2, 4-5) or rather indistinctly and irregularly developed (remane, 1969, figs. 11 b, c; 29 c, d, e), or merely hinted at (de castro, 1996, pl.20, fig. 1). also, a visible difference between the two species concerns the shape of the fertile laterals and how they are attached to the central stem. in c. jurassica, fertile laterals, when leaving the central stem, are slightly inflated (swollen), then slightly taken in and again distally widened, thus acquiring a funnel-like shape. they are attached to the central cavity directly by their broadened base (pl. iii, figs. 1-2, 4-6, 7-9). because of this shape, the laterals in transverse sections, depending on the cutting plane, often appear as oval-shaped pores, seemingly detached from the remaining part of the lateral (pl. iii, pars fig. 7-8). in contrast, this has never been noticed in c. lagustensis. de castro (1997), in the description of his plate 20, fig. 1, mentions a small protuberance in the proximal part of a lateral in c. jurassica. according to our sections, we cannot confirm that determination with certainty, though the section figured in pl. iii, fig. 8, allows for such a possibility. however, in contrast to those features in c. jurassica, fertile laterals in c. lagustensis are attached to the central stem mostly by a short and small stalk, the diameter of the stalk being equal to that of the exit pore. this excludes the possibility of the lateral displaying any sort of an irregular, protuberance-shaped, broadening. in addition to the afore-mentioned differences, there is another essential characteristic feature that easily enables distinction between c. lagustensis and c. jurassica, and this refers to the distance between the neighbouring fertile whorls (h). though in about 20% of measured sections in c. lagustensis this value varies in the range 1:5, the minimum h values in c. lagustensis are approximately equal to the maximum h values in c. jurassica; that parameter seems to be only seldom mentioned in c. jurassica, being measured, apparently, only in a small number of sections. the average h value (= distance between the consecutive whorls) in c. lagustensis is, in about 60-70% specimens, 2-3 times larger, in 10% specimens being even 4 times larger, than in c. jurassica. in addition to these three characteristic differences (morphology of the central stem, the way of attachment of fertile latgeologia croatica 67/2geologia croatica 80 erals to central stalk, and the relation of the h values), there is another characteristic. it concerns the development, shape, and position of the sterile laterals in the interverticillate parts of the central stem. sterile laterals, as described above, have been observed only in the new described species, c. lagu­ stensis. also, we are of the opinion that the majority of sections illustrated by radoičić (1969) and labelled clypeina inopinata, should be assigned to the new species. regarding the above mentioned taxonomic status of c. inopinata, and the opinion of numerous authors of it being a possible synonym of c. jurassica, the characteristics of sterile laterals in c. lagustensis n. sp. (assigned by radoičić to c. inopi­ nata), cannot be unambiguously transferred to c. jurassica. the shape and arrangement of sterile laterals, marked by tiny pores, in some sections of c. jurassica (pl. iii, fig. 9), has remained unknown and incomparable up to the present. with regard to other clypeina species, encountered in the range tithonian-neocomian, the enumerating of differences to c. lagustensis seems unnecessary, because of its specific thallus morphology, intercellular calcification of fertile laterals, and well developed sterile laterals with characteristic features. these characteristics have not been observ ed in any other species within a similar stratigraphic range. some of them, such as c. isabelae masse et al. (masse et al., 1999) and c. loferensis schlagintweit et al. (schlagintweit et al., 2009), besides the stated differences, have thalli that are several times smaller than c. lagustensis n. sp. acknowledgement the samples used for analysis in this paper were collected during geological investigations on lastovo island. in the field work our colleagues igor vlahović, ladislav fuček and damir palenik were also involved, to whom we express our thanks. we are grateful for the financial support that was obtained from the ministry of science and higher education of the republic of croatia through the projects „basic geological map of the republic of croatia scale 1:50.000” and „microfossil assemblages in carbonate sediments of the karst dinarides”. we are particularly thankful to the reviewers ioan bucur and felix schlagintweit for their careful reading of the manuscript and useful suggestions, which contributed to the final version of this paper. references bassoullet, j.-p., bernier, p., conrad, m.a., deloffre, r. & jaffrezo, m. (1978): les algues dasycladales du jurassique et du crétacé.– géobios (lyon), mém. spéc. 2, 330 p. de castro, p. (1997): introduzione allo studio in sezione sottile delle dasicladali fossili (an approach to thin-section study of fossil dasycladales).– quad. accad. pontaniana napoli, 22, 1–26. elliott, g.f. (1968): three new tethyan dasycladaceae (calcareous algae) of the middle east.– palaeontology, 11/4, 491–497. favre, j. & richard, a. (1927): étude du jurassique supérieur de pierre-châtel et de la cluse de la balme (jura méridional).– mém. soc. paléontol.suisse (genève), 46, 1–39. favre, j. (1932): présence d’une nouvelle espèce d’algue calcaire siphonée dans le valanginien du jura central, clypeina inopinata n. sp.– eclogae geol. helv., 25/1, 11–16. granier, b. (1986): algues chlorophyceae du jurassique terminal et du crétacé inférieur en alicante.– mediterránea ser. geol., 5, 5–96. granier, b. & deloffre, r. (1993): inventaire critique des algues dasycladales fossiles: ii. partie – les algues dasycladales du jurassic et du crétacé.– rev. paléobiol., 12/1, 19–6. husinec, a. & read, j.f. (2006): transgressive oversized radial ooid facies in the late jurassic adriatic platform interior: low energy precipitates from highly supersaturated hypersaline waters.– geol. soc. am. bull., 118, 550–556. husinec, a. & read, j.f. (2007): the late jurassic tithonian, a greenhouse phase in the middle jurassic-early cretaceous ‘cool’ mode; evidence from the cyclic adriatic platform, croatia.– sedimentology, 54, 337–317. jagačić, t. (1970): geološki odnosi otoka lastovo.– geol. vjesnik, 23, 69–80. kerčmar, d. (1962): prve najdbe zgornjejurskih apnenih alg v sloveniji.– geologija, 7, 9–24. korolija, b. & borović, i. (1975): osnovna geološka karta sfrj, listovi lastovo k 33-46, korčula k 33-47 i palagruža k 33-57.– institut za geološka istraživanja, zagreb (1967–1968), savezni geološki zavod, beograd. korolija, b., borović, i., grimani, i., marinčić, s., jagačić, t., magaš, n. & milanović, m. (1977): osnovna geološka karta sfrj, tumač za listove lastovo k 33-46, korčula k 33-47 i palagruža k 33-57.– institut za geološka istraživanja, zagreb (1968), savezni geološki zavod, beograd, 53 p. masse, j.p, bucur, i.i., virgone, a. & dalmasso, h. (1999): nouvelles espèces de dasycladales du crétacé inférieur de provence (s.e. france).– rev. micropal., 42, 231–243. remane, j. (1969): morphological and statistical analysis of clypeina jurassica (favre) (dasycladaceae) by means of serial sections.– geol. rom., 8, 85–115. radoičić, r. (1966): microfaciès du jurassique des dinarides externes de la yougoslavie.– geologija, 9, 5–377. radoičić, r. (1969): a new lower cretaceous dasycladacea, cly­ peina pejovici, and note on some clypeinae.– geol. romana, 8, 71–84. roda, c. (1965): il calcare portlandiano a dasycladaceae di m. mutolo (reggio calabria).– geol. romana, 4, 259–290. schlagintweit, f., dieni, i. & radoičić, r. (2009): two lookalike dasycladalean algae: clypeina isabellae masse, bucur, virgone & delmasso, 1999 from the berriasian of sardinia (italy) and clypeina loferensis sp. n. from the upper jurassic of the northern calcareous alps (austria).– geol. an. balk. poluost., 70, 43–59. tišljar, j. (1985): structural type and depositional environments of jurassic coated grain limestones in the southern adriatic region.– krš jugoslavije, 11, 71–99. manuscript received march 18, 2014 revised manuscript accepted april 28, 2014 available online june 17, 2014 sokač et al.: clypeina lagustensis n. sp., a new calcareous alga from the lower tithonian of lastovo island (croatia) geologia croatica 81 plate i 1-6 clypeina lagustensis n. sp. 1, 4-5 longitudinal sections. figs. 4-5, short stalks connecting fertile laterals to the main stem are visible in places. fig 4 shows pronounced thallus micritization. slides: fig. 1, lsl-43/15, x 34; fig. 4, lsl-43/18, x22; fig. 5, lsl-43/27, x 17. 2 longitudinal-tangential section. slidelsl-43/27, x 25. 3, 6 oblique sections. both sections show the micritized outer part of the thallus and short, bent (knee like), stalks in the proximal parts of fertile laterals. slides: fig. 3, lsl-43/23, fig. 6, lsl-43/36, x 25. geologia croatica 67/2geologia croatica 82 plate ii 1-6 clypeina lagustensis n. sp. 1-2 longitudinal sections. fig 2, holotype with remotely spaced fertile whorls. slides: fig. 1, lsl-46/16, fig. 2, lsl-43/27, x 22. 3 tangential-longitudinal section showing clearly pronounced, alternating barrel-like swellings and constrictions of the central cavity. at places, short stalks in the proximal parts of fertile laterals are visible. slide: lsl-43/19, x 22. 4 oblique section, showing remotely spaced fertile whorls. slide lsl-43/1, x 22. 5 tangential-longitudinal section, showing remotely spaced fertile whorls. slide lsl-43/1, x 34. 6 longitudinal section. slide lsl-43/21, x 34. sokač et al.: clypeina lagustensis n. sp., a new calcareous alga from the lower tithonian of lastovo island (croatia) geologia croatica 83 plate iii 1-2, 4-5, 7-9 clypeina jurassica favre 3, 6 clypeina lagustensis n. sp. 1 oblique section. slide og-6462, x 22. 2 tangential-oblique section. slide og-6462/1, x 17. 4-5 longitudinal sections. slides: fig 4, og-6462, x 22; fig. 5, og-6462/1, x 17. 7 transverse section. slide i-4593/1, x 34. 8-9 transverse, slightly oblique, sections. slide: i-4593/1, fig. 8, x 34; fig. 9, x 22. 3, 6 longitudinal sections, showing remotely spaced fertile whorls and short stalks of fertile laterals. slide lsl-43/17, x 28. geologia croatica 67/2geologia croatica 84 plate iv 1-8 clypeina lagustensis n. sp 1, 3 longitudinal-tangential sections. slides: fig. 1, lsl.43/22, x 17; fig. 3, lsl-43/17, x 22. 2, 4-5 longitudinal sections. slides: fig. 2, lsl 43/22, x 14; fig. 4 lsl-43/17, x 34; fig. 5, lsl-43/4, x 34. 6 longitudinal-tangential section. slide lsl-43/3, x 22. 7 fragment of a longitudinal section. slide lsl-43/3, x 34. 8 oblique section cutting a whorl and a part of stalk; clearly visible pores and groups of sterile laterals. slide lsl-43/1, x 34. sokač et al.: clypeina lagustensis n. sp., a new calcareous alga from the lower tithonian of lastovo island (croatia) geologia croatica 85 plate v 1-10 clypeina lagustensis n. sp. 1 oblique section. clearly visible proximal calcification of the thallus with sterile laterals grouped in bundles. slide lsl-43/5, x 34. 2-3 longitudinal sections. slides: fig. 2, lsl-43; fig.3, lsl-43/17, x 22. 5 fragment of a near-surface tangential section. slide lsl-43/21, x 22. 6 oblique section. between fertile whorls, sterile laterals, grouped into bundles, forming clumps. slide lsl-43/4, x 34. 7 tangential section near central cavity. sterile laterals lined in rows, starting to form bundles, grouped into clumps. slide lsl-43/6, x 34. 8 oblique section showing two whorls of fertile laterals, with groups of bundles of sterile laterals in between, irregularly spaced on the stem. 9 transverse section of stem between fertile whorls, showing groups of sterile lateral bundles. slide lsl-43/28, x 22. 10 tangential section of stem between fertile whorls, showing rows of groups of sterile lateral bundles. slide lsl-43/7, x 34. geologia croatica 67/2geologia croatica 86 plate vi 1-12 clypeina lagustensis n. sp. 1 tangential section, showing rows (whorls) of sterile laterals between fertile whorls,starting to group into bundles and form clumps. slide lsl43/15, x 28. 2 transverse section of the stem between whorls, showing pronounced calcification of the clumps and envelopes. slide lsl-43/27, x 34. 3 tangential section showing rows of sterile laterals between fertile whorls. slide lsl-43/22, x 38. 4 oblique section with visible calcite cups of sterile laterals tufts between fertile whorls. slide lsl-43/1, x 34. 5 oblique section with visible rows of bundles grouped in clumps and calcitic cups of sterile laterals, depending on the depth and position of section. slide lsl-43/9, x 34. 6-7 transverse, slightly oblique sections, cutting through parts of the fertile whorls and a part of the stem with sterile laterals. slides: fig. 6, lsl-43/10, x 22; fig. 7, lsl-43/15, x 34. 8-12 transverse sections, showing a varying number of fertile laterals per whorl. slides: fig. 8, lsl-43/20, x 22; fig. 9, lsl-43/10; fig. 10, lsl-43/8; fig. 11, lsl-43/6; fig. 12, lsl-43/18; all x 34. v 1. introduction the carboniferous system and especially the pennsylvanian subsystem provides fossil evidence of the first major radiation of the winged insects, the dominant subclass of the insecta (grimaldi & engel, 2005). the record comprises various bodyand some trace fossils found in finer-grained deltaplain sediments (jarzembowski, 1987). insect fossils are, however, generally uncommon when compared with the abundance of plant compressions. nevertheless, examination of the latter can reveal evidence of insect activity. in this contribution, the first discovery from the croatian pennsylvanian of the ichnospecies phagophytichnus ekowskii van amerom, 1966, on the leaf of the cycadopsid taeniopteris carnotii zeiller, 1888, is described and discussed. animal folivory on leaves is known from the croatian miocene (ðerek & japundžić, 2010), but this find is considerably older (c.~290 ma). 2. geology the tectonic belt of mt. velebit and lika is the best known and most completely developed upper palaeozoic outcrop in croatia, showing more or less continuous sedimentation from the middle pennsylvanian (moscovian) to the endpermian (changhsinghian) (jasenka sremac pers. comm., 2011; japondžić, krizmanić, poljak & mjeda, 2005). upper kasimovian-gzhelian sediments are extensive, recording the rhythmic oscillations of sea-level fluctuation. fossiliferous marine sediments predominate over sporadic beds of continental origin, the shoreline having never been far away. plant compression fossils occur in grey mudstones in the lika region from which the trace fossil is described below. the lika find is compared with upper ladinian material from germany found in fluvial sediments and associated with a low sea-level stand (grauvogelstamm & kelber, 1996). 3. systematic palaeontology ichnogroup phagophytichnidea vasilenko, 2007b ichnosubgroup phagophytichnida vasilenko, 2007b ichnofamily phagophytichnidae vyalov, 1975 ichnosubfamily phagophytichninae vyalov, 1975 ichnogenus phagophytichnus van amerom, 1966 remarks. phagophytichnus is a long-ranging ichnogenus of marginal leaf-biting species and usually considered to be the result of insect chewing (as opposed to gastropod rasping (by land snails/slugs), retallack, 2001: p. 137). ab stra ct the feeding trace phagophytichnus ekowskii van amerom, 1966 is recorded on taeniopteris carnotii zeiller, 1888, a cycadopsid leaf, from the lika mudstone (upper kasimovian-gzhelian) of croatia. the distribution and occurrence of this ichnogenus and species are discussed and comparison made with occurrences on taeniopteris angustifolia (schenk, 1927) in the upper landinian of germany. recent analogues are considered of the possible producer and an orthopteroid insect is suggested. keywords: pennsylvanian, ladinian, phagophytichnus ekowskii, cycadopsid, taeniopteris carnotii, chewing geologia croaticageologia croatica the oldest plant-insect interaction in croatia: carboniferous evidence  ed a. jarzembowski nanjing institute of geology and palaeontology, chinese academy of sciences, nanjing 210008, china; (jarzembowski2@live.co.uk) doi: 104154/gc.2012.28 geologia croatica 65/3 387–392 1 pl. zagreb 2012 geologia croatica 65/3geologia croatica 388 originally referred to the cibichnia or feeding (eating) traces, phagophytichnus was then included in praedichnia, trace fossils of predation, but more recently moved to phagophy tichnidea, feeding traces on plants (vasilenko, 2007b), and even been given its own family, phagophtyichnidae (vyalov, 1975). zherikhin (2003) previously placed pha gophytichnus in trogichnia reserved for chew marks on plants. evidence that the living plant was predated is provided by a pronounced thickening (ridge) sometimes seen along the damaged margin and interpreted as callus (‘scab’) formation (see figure of damaged leaf of the pteridosperm macroneuropteris scheuchzeri (hoffmann) cleal, shute & zodrow from the late asturian of england in attenbo rough, 2005: p.167). this was previously interpreted as leaf mining (müller, 1982). distribution. phagophytichnus has been described from the late mississippian to the pliocene and has a worldwide distribution (iannuzzi & labandeira, 2008; brustur, 1997). it also represents the most common type of external foliage feeding in the fossil record (labandeira, 2006). the inclusion of small holes in ginkgoalean foliage from the lower cretaceous, however, overstretches the generic limits of phagophytichnus (watson, lydon & harrison, 2001). these traces are trogichnia or nygmichnia (chewing or piercing marks respectively) following zherikhin (2003, tab. iii), the latter not included in vyalov (1975). like phagophytichnus, these marks are both included in zherikhin’s ‘redundant’ phagophytichnia: phyllophagichnia (leaf and petiole damage). for ease of reference, i propose to call them porichnid (from the ancient greek poros, hole, and latin ichnus, trace) within vasilenko’s phagophytichnida pending a more detailed study. phagophytichnus ekowskii van amerom, 1966 (pl. 1, figs. 1–2) = cuniculonomus (arcophionomus) undulatus mül ler, 1982 = damage type 12 (labandeira, wilf, johnson & marsh, 2007) diagnosis: an approximately semicircular, isolated excision (cut out) of the leaf margin which is shallow or deep but less than 180 degrees of arc (labandeira et al., 2007). description and measurements: the lika trace fossil is cuspate excisions (overall length c. 2 cm, width 3 mm) from the margin of the leaf of taeniopteris carnotii zeiller, 1888 (nĕmejc, 1936) preserved as a compression in mudstone (pl. 1, figs. 1a–c). it comprises 2 to 3 semicircular, asymmetrically curved, successive and separate excisions, each of which is up to 9 mm long, and all approaching the midpoint of the distance between the leaf margin and midvein. material (figured), locality and date: specimen 1 (pl. 1, figs. 1a–c). registration number: 10776. repository: geology-palaeontology department, croatian museum of natural history. locality lika region, east of mt. velebit, croatia. age: stephanian c (late kasimovian to gzhelian). specimen 2 (pl. 1, fig. 2). registration number: schl061a. repository: kelber collection. locality: scheerich, franconia, germany. age: lower keuper, upper landinian. remarks. the lika ichnofossil (upper pennsylvanian, c. 305 ma) is of a similar size to marginal excisions on taeniopteris angustifolia (schenk, 1927) from the late middle triassic (c. 230 ma) of scheerich, germany (cf. geyer & kelber, 1987: fig. 7, lower left and kelber & geyer, 1989: pl. 2, figs 3, 5; also kelber & gayer, 1989: figs 4, 6, another specimen). one of these triassic leaves, however, figured herein is extensively eaten (pl. 1, fig. 2) with successive marks (kelber & geyer, 1987), although a new find shows two widely spaced excisions, one comparatively small (steinkern, 2011). both carboniferous and triassic specimens are similar in that their location is away from the midvein of the leaf and occurrence along one margin. the triassic material has been only tentatively referred to phagophytichnus (grauvogel-stamm & kelber, 1996), but like the lika specimen, can be referred to p. ekowskii, as currently diagnosed. in the absence of cuticular studies, taeniopteris carnottii may be a cycad or a bennettite within the class cycadopsida barnard & long (cf. cleal & rees, 2003), and possibly a synonym of taeniopteris multinervis weiss, 1869 (chris cleal, pers. comm., 2012). distribution (range and occurrence): phagophytichnus was originally based on p. ekowskii found on the pteridosperm mixoneura weiss (mixoneura wagneri lorenzo nec neuropteris praedentata gothan; castro, 1997), from the spanish stephanian b (van amerom, 1966). the stratigraphic range of p. ekowskii was subsequently extended from the late mississippian to the late triassic and the host range extended to various other pteridosperm genera including: autunia krasser, dicroidium gothan, glossopteris brongniart, macroneuropteris cleal, shute & zodrow, neuropteris brongniart paripteris gothan, odontopteris (brongniart) sternberg, pursongia zalessky, triphyllopteris schimper, and the ginkgopsid dejerseya herbst (iannuzzi & labandeira, 2008; labandeira, 2006; labandeira & allen, 2007; trout, labandeira & chapman, 2000; vasilenko, 2007a). vasilenko (2007b) recorded it (as p. ekovskii) on ferns and pteridosperms as late as the cretaceous (cenomanian), but he referred bite (chew) marks on other gymnosperms (conifers and gingkos) to the ichnogenus pinovulnus vasilenko, although the smaller pinovulnus serpentiformis vasilenko resembles p. ekowskii and there may be some overlap (cf. vasilenko, 2006, fig. 5 and pl. 1, fig. 1). he was evidently following zherikhin’s (2003) classification based on plants rather than functional-feeding groups. as for geographic range, phagophytichnus ekowskii is now worldwide (laurasia + gondwana), being known from euramerica to australasia (lobue & hasiotis, 2010; srivastava & agnihotri, 2011; prevec et al., 2009). in addition, it is formally recorded on cycadopsid leaves (taeniopteris species) from the upper pennsylvanian of croatia and middle triassic of germany herein. ed a. jarzembowski: the oldest plant-insect interaction in croatia: carboniferous evidence geologia croatica 389 attribution: labandeira et al. (2007) attributed this isp. to protorthopteran/stem-orthopteroid insects, whilst allowing that other mandibulate (jaw-bearing) arthropods might be involved (diplopod millipedes), whereas gu, béthoux & ren (2011) stressed a preference for carnivory in these insect groups. geyer & kelber (1987) and kelber & geyer (1989) considered that holometabolous insects, especially the caterpillars of lepidoptera (moths and butterflies) could also be responsible for this isp. as well as orthopterans (grasshoppers and crickets). body fossils of lepidoptera are known by the lower jurassic and hymenoptera (sawflies, ants, bees and wasps), which also have a caterpillar larva, are known by the upper triassic although orthoptera are known from the pennsylvanian onwards (jarzembowski, 2003). millipedes are not considered to be a significant defoliator today but orthopterans are a large and diverse order with herbivorous and carnivorous forms (key, 1970). a bush cricketlike insect may therefore have been responsible for the feeding damage on european taeniopteris, although it is unlikely to be always the same species due to a significant time gap (~c. 75 ma) between the lika and scheerich leaves, and an unknown stem-holometabolan might be involved. beck & labandeira (1998) also recognised orthopteroid damage on taeniopteris sp. from the early-middle permian of the usa differing from p. ekowskii in including leaf holes as well as marginal feeding, but supported by the presence of veinal strands as produced by recent short-horned grasshoppers. the latter are also present in chew marks on leaflets of anomozamites villosus pott, mcloughlin, wu & friis, 2012, a newly described cycadopsid from the middle jurassic of plate 1 phagophytichnus ekowskii on taeniopteris carnotii, lika. 1a – part, middle right. the undulation in the leaf margin (top right) is sedimentary. scale: 20 lipa coin,18 mm diameter; 1b – close up of part in a; 1c – close up of counterpart. 2 – p. ekowskii on taeniopteris angustifolia, sche er ich. note callus formation. 3 – psophus stridulus on taraxacum officinale, recent. scale line, 1 cm. redrawn after kazakova (1985). 1a 1b 2 1c 3 geologia croatica 65/3geologia croatica 390 china (pers. obs.). examination of the lika leaf under magnification was however inconclusive, revealing irregularities along the margin, but also embedding in an obscuring, grainy matrix (but see gross cf. below). 4. recent analogue grasshoppers and caterpillars are unrelated insects but share mandibulate (basic chewing) mouthparts. modern lepidopteran (butterfly) caterpillars are known to defoliate some cycads, such as the cycad blue (theclinesthes onycha hewitson) in australia. cycads are no longer native to europe, but i have often observed caterpillars feeding on angiosperms in southeast england. the caterpillar’s numerous paired legs are used to hold on to the leaf, often tenaciously. as in other mandibulate insects, the paired jaws are orientated beneath the anterior part of the head capsule and the edge of the leaf is harvested in a sideways cutting motion. the head moves progressively forwards and downwards, sometimes obliquely, to obtain purchase and then access to fresh tissue. this would produce a curved excision as seen on the fossil leaves. slight body movements coupled with a break in feeding, often due to a disturbance, result in an excision with subordinate cuspules evident (cf. kelber & geyer, 1989: fig. 4; also, grauvogel-stamm & kelber, 1996: fig. 6). the insect may resume feeding, or move on allowing wound reaction (callus) tissue and subsequent drying out to form a thickening inside the damaged margin as seen on fossils (e. g. pl. 1, fig. 2). my observations on bullace (prunus insititia l.) point to this thickening of the callus being a gradual process, taking weeks to form a feature prominent enough to be readily seen on compression leaves. this could explain the apparent absence of callus in p. ekowskii in jarzembowski (2004: pl. 1, fig. 3). bush crickets are less easy to watch, but such a great green ‘grasshopper’ fed on lettuce showed broadly similar chewing behaviour (michaël, 2011). gangwere (1966) discussed feeding in more derived orthopteroids (acridiid grasshoppers): interestingly, some of the chew marks produced by the rattle grasshopper (psophus stridulus (l.)), a recent forbivorous european species, show a comparable outline to the lika fossil (pl. 1, fig. 3). modern land snails, such as helix aspersa (müller), can also form marginal incisions and holes in leaves by rasping downwards and sideways with their radulae. terrestrial molluscs are scarce in the carboniferous-triassic of europe, but have been found in middle pennsylvanian nodules with plants and insects in the upper silesian coalfield and in the middle/upper pennsylvanian of the english midlands, investigated during igcp 469 (stworzewicz, szulc & pokry szko, 2009). where known, the affinities of carboniferous european snails (ellobioid and cerion-like, loc. cit.) suggest that they fed on detritus or non-vascular plants by analogy with recent thorn and peanut snails rather than the leaves discussed herein. the situation is similar in the late pennsylvanian of north america, such as at joggins, in newfoundland, also investigated during igcp 469 (falcon-lang, benton, braddy & davies, 2006; molluscan detritivory rather than folivory (leaf feeding) was also suggested by solem & yochelson, 1979). in the absence of slime trails and coprolites, stereo-electron microscopy on well-preserved fossil plants may help to distinguish the work of biting mandibles from rasping radulae in future studies. 5. conclusion phagophytichnus ekowskii provides fossil evidence for a long and wide-ranging, generalised feeder with low host specificity, principally on pteridosperm leaf margins. grauvogelstamm & kelber (1996) considered phagophytichnus on taeniopteris, however, as part of a novel insect-plant interaction on mesozoic cycadopsida following the permo-triassic extinction event. the lika find shows that the phagophytichnus-taeniopteris association is considerably older, dating back to the late palaeozoic (upper pennsylvanian). insects are otherwise unknown from the croatian carboniferous and this discovery also helps to fill a gap in the pennsylvanian record of southeast europe. its rarity is, however, not surprising because taeniopteris was likely more resistant than pteridosperms to insect attack due to the cycadopsid’s tougher cuticle and well-developed resin glands (beck & labandeira, 1998). in contrast, the hirsute leaves of macroneuropteris may have only slowed down chewing (attenborough, 2005, figure p. 167). igcp 575 is concerned with environmental change at the middle/upper pennsylvanian transition. the lika flora needs to be examined further to determine the extent of insect herbivory, the current data predicting higher rates of pteridosperm folivory by insects unless carnivory was widespread. a search for associated fauna may provide clues to a more precise identification of the consumer. acknowledgement i wish to thank: the geological society and royal society of london for financial support to visit croatia; the staff at the croatian museum of natural history and geology department, university of zagreb, for their kindly hospitality; conrad labandeira (smithsonian institution) for helpful comments; klaus-peter kelber (würzburg) for copies of his papers and use of pl. 1, fig. 2; james jepson (manchester university), chris cleal (national museum of wales), wendy cawthorne (geological society of london), xavier delclòs (barcelona university), jason dunlop (museum für naturkunde), andré nel (muséum national d’histoire naturelle), jörg schneider (bergakademie freiberg) and library staff at the natural history museum (london) for help with papers; fred clouter (isle of sheppey) and prof. tihomir marjanac (faculty of science, geology department) for improving my figures; my wife, brigid, for garden ecology; conrad labandeira and olivier béthoux (commonwealth scientific and industrial research organisation) for their reviews. this paper is a contribution to igcp 575 and is supported by the chinese academy of sciences visiting professorship for senior international scientists, grant no. 2011t2z04. ed a. jarzembowski: the oldest plant-insect interaction in croatia: carboniferous evidence geologia croatica 391 references amerom, h.w.j. van (1966): phagophytichnus ekowskii nov. ichnogen. & nov. ichnosp., eine missbildung infolge von insektenfrass aus dem spanischen stephanien (provinz leon).– leid. geol. meded., 38, 181–184, pls. 1–3. attenborough, d. (2005): life in the undergrowth.– bbc books, london, 288 p. beck, a.l. & labandeira, c.c. (1998): early permian insect folivory on a gigantopterid-dominated riparian flora from north-central texas.– palaeogeogr. palaeoclimatol. palaeoecol., 142, 139–173. brustur, t. (1997): the stages of paleoichnological studies in romania. proceedings of the international workshop on fluvial-marine interactions, 1996, mainas, 205–216. castro, m.p. (1997): huellas de actividad biológica sobre plantas del estefaniense superior de la magdalena (león, españa).– rev. esp. paleontol., 12/1, 52–66. cleal, c.j. & rees, p. m. (2003): the middle jurassic flora from stonesfield, oxfordshire, uk.– palaeontology, 46, 739–801. ðerek, t. & japundžić, s. (2010): tragovi aktivnosti fosilnih insekata na miocenskim biljkama [traces of fossil insect activity on miocene plants – in croatian].– in: horvat, m. (ed.): 4th croatian geological congress, šibenik 14.–15.10.2010., abstracts book, p. 54. falcon-lang, h.j., benton, m.j., braddy, s.j. & davies, s.j. (2006): the pennsylvanian tropical biome reconstructed from the joggins formation of nova scotia, canada.– j. geol. soc.,163, 561–576. gangwere, s.k. (1966): relationships between the mandibles, feeding behaviour, and damage inflicted on plants by the feeding of certain acridids (orthoptera).– mich. ent., 1/1, 13–16. geyer, g. & kelber, k.-p. (1987): flügelreste und lebensspuren von insekten aus dem unteren keuper mainfrankens.– neues jb. geol. paläontol. abh., 174/3, 331–355. grimaldi, d. & engel, m.s. (2005): evolution of the insects.– cambridge university press, cambridge, xv + 755 p. grauvogel-stamm, l. & kelber, k.-p. (1996): plant-insect interactions and coevolution during the triassic in western europe.– paleontol. lombarda, n.s. v, 5–23. gu, j., béthoux, o. & ren, d. (2011): longzhua loculata n. gen. n. sp., one of the most completely documented pennsylvanian archaeorthoptera (insecta; ningxia; china).– j. paleontol., 85/2, 303–314. iannuzzi, r. & labandeira, c.c. (2008): the oldest record of external foliage feeding and the expansion of insect folivory on land.– ann. entomol. soc. am., 101/1, 79–94. japundžić, s., krizmanić, k., poljak, j. & mjeda, l. (2005): kameniti oblici velebita.– hrvatski prirodoslovni muzej, zagreb, 48 p. jarzembowski, e.a. (1987): the occurrence and diversity of coal measure insects.– j. geol. soc., 144, 507–511. jarzembowski, e. a. (2003): palaeoentomology: towards the big picture.– in: krzemińska, e. & krzemiński, w. (eds.): proceedings of the 2nd congress on palaeoentomology, 2001, kraków. acta zool. cracov., 46 (supplement), 25–36. jarzembowski, e.a. (2004): atlas of animals from the late westphalian of writhlington, united kingdom.– geologica balk., 34/1–2, 47–50, pls. 1–2. kazakova, i.g. (1985): zharakter povrezhdeniya rastenii pryamokrylymi nasekomymi v svyazi so stroeniem ikh rotovogo apparata.– in: zolotarenko, g.s. (ed.): antropogennye vozdeistviya na soobshchestva nasekomykh akademia nauk ssr, novosibirsk, 122–127. kelber, k.-p. & geyer, g. (1989): lebensspuren von insekten an pflanzen des unteren keupers.– cour. forschinst. senckenberg, 109, 165–174. key, k.h.l. (1970): orthoptera.– in: mackeras, i.m. (ed.): the insects of australia, melbourne university press, carlton, 323–347. labandeira, c. (2006): silurian to triassic plant and hexapod clades and their associations: new data, a review, and interpretations.– arthropod systematics and phylogeny, 64/1, 53–94. labandeira, c.c. & allen, e.g. (2007): minimal insect herbivory for the lower permian coprolite bone bed site of north-central texas, usa, and comparison to other late paleozoic floras.– palaeogeogr. palaeoclimatol. palaeoecol., 247, 197–219. labandeira, c.c., wilf, p., johnson, k.r. & marsh, f. (2007): guide to insect (and other) damage types on compressed plant fossils, version 3.0. smithsonian institution, washington d. c., 25 p. lobue, d.j. & hasiotis, s.t. (2010): ichnotaxonomic assessment of mazon creek area trace fossils.– abstr. prog. geol. soc. am., 42/2, p. 93. michaël. (2011): green ‘grasshopper’ eating salad. http://vimeo.com/ (retrieved 12/10/2011) müller, a.h. (1982): über hyponome fossiler und rezenter insekten, erster beitrag.– freib. forschungsh. reihe, c 366, 7–27. nĕmejc, f. (1936): contribution to the knowledge of the carboniferous flora of the coal measures at the north-eastern foot of the velebit mountains (yougoslavia).– bull. int. acad. sci. bohĕme, 1936, 1–16, pls. i–iii. pott, c., mcloughlin, s., wu, s. & friis, e.m. (2012): trichomes on the leaves of anomozamites villosus sp. nov. (bennettitales) from the daohugou beds (middle jurassic), inner mongolia, china: mechanical defence against herbivorous arthropods.– rev. palaeobot. palynol., 169, 48–60. prevec, r., labandeira, c.c., neveling, j., gastaldo, r.a., looy, c.v. & bamford, m. 2009. portrait of a gondwanan ecosystem: a new permian fossil locality from kwazulu-natal, south africa.– rev. palaeobot. palynol., 156, 454–493. retallack, g.j. (2001): soils of the past: an introduction to paleopedology.– 2nd ed. blackwell, oxford, ix + 414 p. solem, a. & yochelson, e.l. (1979): north american paleozoic land snails, with a summary of other paleozoic nonmarine snails.– prof. pap. u. s. geol. surv., 1072, iii + 42 p., pls. 1–10. srivastava, a.k. & agrinotri, d. (2011): insect traces on early permian plants of india.– paleontol. j., 45/2, 200–206. steinkern. (2011): phagophytichnus taeniopteris http://www.steinkern.de/index.php? (retrieved 20/10/2011). stworzewicz, e., szulc, j. & pokryszko, b.m. (2009): late paleozoic continental gastropods from poland: systematic, evolutionary and paleoecological approach.– j. paleontol., 83/6, 938–945. trout, m.k., labandeira, c.c. & chapman, r.e. (2000): a morphometric analysis of insect damage on neuropteris and implications for paleozoic herbivory.– abstr. progm geol. soc. am., 32/7, 219–220. vasilenko, d.v. (2006): margin feeding damage on the leaves of conifers and ginkgoales from the mesozoic of transbaikalia.– paleontol. j., 40/3, 286–289. vasilenko, d.v. (2007a): feeding damage on upper permian plants from the sukhona river.– paleontol. j., 41/2, 207–211. vasilenko, d.v. (2007b): evidence of terrestrial arthropod and plant interaction from the upper mesozoic of asia.– unpublished phd thesis, moscow state forest university. geologia croatica 65/3geologia croatica 392 vyalov, o.s. (1975): the fossil traces of insect nourishment [in russian].– paleontol. sb., 12/1–2, 147–155. watson, j., lydon, s.j. & harrison, n.a. (2001): a revision of the english wealden flora, iii: czekanowskiales, ginkgoales and allied coniferales.– bull. nat. hist. mus. lond. (geology), 57/1, 29–82. zherikhin, v.v. (2003): insect trace fossils, their diversity, classification and scientific importance.– in: krzemińska, e. & krzemiński, w. (eds): proceedings of the 2nd congress on palaeoentomology, 2001, kraków. acta zool. cracov., 46 (supplement), 59–66. manuscript received december 28, 2011 revised manuscript accepted september 10, 2012 available online october 30, 2012 05-jurkovic.indd 49 � ab stra ct the geochemical characteristics of tetrahedrite and barite of the duboki vagan barite deposit near the town of kreševo in the mbsm (mid-bosnian schist mountains) have been determinated and correlated with the results of previously studied barite, from the adjacent glumac deposit, and fl uorite, from the dubrave-dugi dol barite deposits. the studied tetrahedrite is characterized by a high content of au (39 ppm) and ag (>300 ppm), the presence of co (63.5 ppm), ni (266.2 ppm) and cd (313,6 ppm) in the crystal lattice and negative δ34scdt values (–11.80‰). on the plot of its c1 chondrite-normalized ree abundances, a slightly expressed positive eu anomaly and high hree concentrations are observed. the high content of srso4 (2.33 to 3.42 wt.%) in the barite crystal lattice indicates hydrothermal parent solutions. the δ34scdt values of the studied barite are +10.40‰, which is typical for permian seawater and its δ18osmow values range between 15.6 and 17.7‰. a distinct positive eu anomaly is shown on the plot of the c1 chondrite-normalized ree abundances in barite. geochemical characteristics of the studied tetrahedrite and barite of duboki vagan are very similar to those of previously investigated glumac and dubrave-dugi dol barite deposits. the fl uorite from the dubrave-dugi dol deposits displays a negative eu anomaly and its tb/la and tb/ca ratios indicate a quite different origin in relation to barite formation. this is all in the accordance with the possible existence of two different paragenetic types of barite deposits in the mbsm and seb (southeastern bosnia), which signifi cantly differ in the δ18osmow ranges of their barites and δ34scdt values of their sulphides. the fi rst type of barite deposits originated in the late variscan phase (lower permian). it is characterized by numerous cu, fe, zn, sb, as, pb sulphides and cu-sb-tetrahedrite without mercury, all having positive δ34scdt values (0 to +5 ‰). early intercontinental rifting took place between the uppermost permian and lower triassic and enabled, in a great number of ba rite deposits, (especially in the mbsm), remobilization and partial fl uidization of their fe, cu, zn, sb and pb sulphides which reacted with ascended mercury, sulphur and fl uorine rich mantle fl uids and resulted in the formation of hgtetrahedrite and octahedral fl uorite. these processes caused the occurrence of the second paragenetic type of barite deposit with hg-tetrahedrite as the main ore mineral, but characterized by strongly negative δ34scdt values. keywords: paleozoic, mid-bosnia, hg-tetrahedrite, barite, fl uorite, stable isotopes (s, c and o), trace elements, ree, genesis geochemical characteristics of mercurian tetrahedrite, barite and fl uorite from the duboki vagan, glumac and dubrave-dugi dol barite deposits, south of kreševo, mid-bosnian schist mts. � ivan b. jurković1, vesnica garašić1 and ivan m. jurković2 1faculty of mining, geology and petroleum engeneering, university of zagreb, pierottijeva 6, 10 000 zagreb, croatia; (vesnica.garasic@rgn.hr) 2vladimira ruždjaka 25, 10 000 zagreb, croatia doi: 104154/gc.2011.05 geologia croatica 64/1 49–59 4 figs. 4 tabs. zagreb 2011 geologia croaticageologia croatica geologia croatica 64/1geologia croatica 50 1. introduction in the mid-bosnian schist mountains (mbsm) and southeastern bosnia (seb) two completely different paragenetic types of barite deposits occur. small amounts (<10%) of diverse sulphides (pyrite, chalcopyrite, sphalerite, galena, arsenopyrite and tetrahedrite without mercur) occur with barite in the fi rst type. the second type of barite deposit is almost monosulphidic containing only hg-tetrahedrite. there is a remarkable geochemical difference between the sulphides of these two types of barite deposits. all sulphides of the fi rst type are characterized by positive δ34scdt values (0 to +5‰), whereas the hg-tetrahedrite of the second type contains negative δ34scdt values (–4.95 to –15.40‰). additionally, jurković et al. (2010), found that the δ18osmow values in barite of the fi rst polysulphide type are signifi cantly lower (+14.2‰ to +15.6‰) than the δ18osmow values in barite from the second monosulphidic hg-tetrahedrite type (+15.8‰ to +22.4‰). such differences can be explained by lower temperature and lower salinity of mineralisation in the fi rst type of barite deposits jurković et al. (2010). these authors state that the fi rst polysulphide paragenetic type of barite deposits originated in late variscan phase (lower permian). the second one originated in post variscan/early eoalpine phase due to the exposure of the fi rst barite deposit type to the impact of early intercontinental rifting (jur ković et al., 2010). the aim of this work is to investigate the geochemical characteristics of the tetrahedrite and barite of the duboki vagan barite deposit near kreševo in the mbsm, correlate them with the results of previously studied barite from the adjacent glumac deposit and fl uorite from the dubrave-dugi dol barite deposits. in addition a broad comparison of these results with geochemical characteristics of the other barite deposits in the mbsm and seb will be made. 2. geology and paragenesis of the barite deposits 2.1. geology the duboki vagan, glumac and dubrave-dugi dol barite deposits occur in the area which surrounds the town of kreše vo and belongs to the mid-bosnian schist mountains (mbsm). according to jovanović et al. (1977, 1978), rocks of palaeozoic and triassic age have been recognized in this area. the lowermost part of the palaeozoic sequences includes chlorite and muscovite schists, phyllites and argillaceous schists, quartzites and lidites. the overlying dolomites, dolomitic limestones and marbles are found to be devonian in age (sofilj et al., 1980). magmatic rocks occur as porphyrites forming sills within chlorite and muscovite schists, and as quartz porphyry and keratophyre extrusions being situated on the verge of the devonian carbonate complex (jurković, 1987). the youngest palaeozoic sediments consist of conglomerates, sandstones, phyllites with permian fl ora and brecciated limestones (jurković, 1987). the lower triassic is represented by sandstones, clay-like schists, marls and rare limestones, while the middle triassic is composed of dolomites and limestones. the lower ladinian horizons consist of sandstones, hornstones, marls, claylike schists and rare limestones, whereas limestones dominate in upper ladinian horizons (jurković, 1987). the geological relationships between the lower palaeozoic metamorphic complex and the overlying (<300 m thick) carbonate complex are not clear. the occurrence of barite deposits is exclusively related to the upper silurian – devonian metaclastites and dolomites (fig. 1). 2.2. duboki vagan the northern border of the duboki vagan ore deposit runs 1 km south of the town of kreševo and its southern limit is 4 km south of kreševo (fig. 1). the duboki vagan lies at absolute altitudes of +800 to +1000 m. barite is the main ore mineral (50−75% of the ore mass), while pyrite and hg-tetrahedrite (2–3%) are subordinate ore minerals. quartz is the main gangue mineral (25–33% of the ore mass), followed by subordinate siderite (which is strongly oxidized into goethite). octahedral fl uorite is an accessory mineral. the deposit is hosted by the devonian dolomite, intruded by a large mass of metarhyolite (1–2 km2) which crystallized from an s-type granitoid magma (jurković et al., 2010). the duboki vagan deposit lies in a large, 20 m deep karstifi ed depression. the bottom of the depression is fi lled with rubble and blocks of siliceous barite which represented gangue from an earlier time. part of this material comes from mining operations, but part is the residue left by the weathering and leaching out of the ore-bearing devonian dolomite. the ancient miners removed only cinnabar, which was necessary for the amalgamation of gold from hg-tetrahedrite, and limonite used in the production of iron. in recent times the old dumps and elluvial deposits have been worked over and barite recovered. this clearing up has afforded a better view of the morphology of the duboki vagan barite deposit. the ore bodies are irregular seams running nw–se, 1–1.5 m thick, dipping towards the ne, but there are also satellite barite veins. recently, miko performed a quantitative chemical analysis of one hg-tetrahedrite sample from the duboki vagan deposit (jurković & miko, 1997) which determined the weight % composition of: 37.53 cu; 1.09 fe; 4.69 zn; 0.129 ag; 2.45 hg; 1.41 as; 24.25 sb; 0.20 bi; 25.03 ws; 154.50 ppm au (σ = 97.70 wt.%). 2.3. dubrave-dugi dol dubrave-dugi dol barite deposits are located ~ 1 km southeast of međuvršje summit (+1195 m) and 3 km southeast of kreševo. according to jurković & miko (1997), the ore is hosted in dolomite of devonian age and occurs as irregular nests, lense-shaped veins, networks of veinlets or as breccias in tectonically dislocated dolomites. these authors also noted signifi cant allochtonous residual barite deposits on a karstifi ed dolomite relief. a detailed description of the mineral paragenesis was given by jurković (1987). he pointed out that the main mineral is barite, hg-tetrahedrite is the jurković et al.: geochemical characteristics of mercurian tetrahedrite, barite and fl uorite from the duboki vagan, glumac... geologia croatica 51 most frequent sulphide at 1–5 wt.%, whereas pyrite, chalcopyrite i and ii, and two unidentifi ed copper sulphosalts, colloform pyrite and goethite are accessories. hg-tetrahedrite replaces barite grains along margins and fi ne fi ssures (jurković, 1987). quartz i and ii occur as gangue minerals, as does transparent fl uorite, being violet or colourless, and scarce leaves of sericite and rutile (jurković, 1987). quantitative chemical analyses of the hg-tetrahedrite sample from the dubrave-dugi dol ore deposits, performed by miko (jurković & miko, 1997), is expressed (wt%) as: 40.62 cu; 2.63 fe; 3.81 zn; 0.29 ag; 0.33 hg; 1.98 as; 25.44 sb; 0.06 bi; 24.78 s; 8.30 ppm au (σ = 99.94 wt.%). 2.4. glumac the glumac barite deposits are situated at elevations of 800 to 920 metres above sea level on the northern side of me đuvršje mountain and ~1 km south of kreševo. ore bodies occur in different forms (nests, veins, irregular bodies, ore breccias), and are usually very irregular (jurković, 1987). the main mineral is barite, whereas calcite, ankerite, fl uorite, neodolomite, hg-tetrahedrite, pyrite and quartz are subordinate (jurković, 1987). chemical analysis of the hgtetrahedrite sample from glumac–vidici location, which is a part of glumac barite occurrences, indicated the following composition (wt%): 40.26 cu; 4.15 fe; 1.22 zn; 0.20 ag; 1.83 hg; 2.73 as; 24.89 sb; trace bi; 24.22 s; 0.20 loi; 13.40 ppm au, σ = 99.70 wt.% (jurković, 1987). 3. research history the fi rst data on ore deposits and mining works in the area of duboki vagan come from wolf (1847). these deposits were later investigated by conrad (1870), herbich (1880, 1880a), vogt (1880), walter (1887), katzer (1907), jurković et al. (1951), jurković (1956, 1958), jeremić (1963), mikolji (1969), jovanović et al. (1977), jurković (1987, 1988), jurković et al. (1997) and jurković & miko (1997). jurković (1956, 1988) produced the fi rst detailed ore paragenesis from the duboki vagan deposit and identifi ed the genetic position of this type of ore deposit in the mbsm. he established hypogenic and hypergenic parageneses. the hypogenic paragenesis includes barite, quartz i, siderite, pyrite, ankerite, hg-tetrahedrite, sericite, kaolinite (?), fl uorite and quartz ii. the hypergenic paragenesis consists of goethite, lepidocrocite, “basic sulphates”, cinnabar, malachite, azurite, elemental gold, manganomelane, pyrolusite and chal cedony. examination of the waste heaps and elluvial material has revealed that barite is the main mineral, with signifi cant quantities of quartz, lesser amounts of pyrite, signifi cantly less hg-tetrahedrite (exploited by roman and medieval miners), and a considerable quantity of au-ag-bearing limonite. katzer (1907) determined the approximate relationship of the main minerals: 40.2% barite, 32.6% quartz, 2.4% tetrahedrite, 0.8% cu and 24.8% soluble matter what is equal 100.8% in total. jurković et al. (1997) presented the fi rst geochemical data of barite and tetrahedrite from the duboki vagan barite deposit (see tables 1 and 3). 4. analytical methods the quantitative chemical analysis of hg-tetrahedrite (dvagt sample) was performed by acme analytical laboratories, vancouver ltd., canada (table 1). the trace element content of hg-tetrahedrite (d-vagt sample) and barites (vag and duv samples) was analysed by inductively coupled plasma (icp) mass spectrometry in the same laboratory (tables 2 and 3). the isotope composition of sulphur in the hg-tetrahedrite (d-vagt), oxygen in barite (vag) and sulphur and oxygen in barite (duv) were determined in the stable isotope laboratory of the university of laussane, swiss, using a finnigan mat facility (table 4). fi gu re 1: geological map of the duboki vagan, glumac and dubrave-dugi dol barite deposits, south of kreševo, bosnia (modifi ed from jurković, 1987). geologia croatica 64/1geologia croatica 52 the chemical composition of hg-tetrahedrite from the duboki vagan barite deposit was determined by slobodan miko (in jurković & miko, 1997) by atomic absorption spectrometry (aas) and by icf-aes after br-hcl digestion (table 1). two clear fl uorite crystals from the dubrave-dugi dol barite deposits were analysed 15 years ago by inaa (instrumental neutron activation analysis) in the institute for petrology and geochemistry, karlsruhe university, germany (palinkaš & jurković, 1994). 5. results 5.1. hg-tetrahedrite the analysed hg-tetrahedrite (sample d-vagt) from duboki vagan was very fi ne-grained, densely dispersed in the gangue consisting of barite, quartz and calcite. tetrahedrite grains were carefully handpicked under a binocular microscope. the chemical analysis revealed that it is a mercurybearing cu-sb-zn tetrahedrite, strongly weathered, containing ~ 2.73 wt.% of mechanically admixed barite, (which has 3.425 wt.% srso4 built into its crystal lattice), calcite and galena (table 1). co (63.5 ppm), ni (266.2 ppm) and cd (313.6 ppm) were detected in the crystal lattice of the tetrahedrite for the fi rst time in the mbsm (table 1). these elements, together with bi, w, sn and se, are constituent elements in the tetrahedrite crystal lattice (duda et al., 1987). their concentrations so far in analysed barite samples, (7 from the mbsm and 6 from the seb), were mostly below minimal detection limits (mdl) and only rarely around mdl. this suggests that the presence of admixed barite in the analysed sample could only inconsiderably infl uence the abundance and distribution of trace elements in the hg-tetrahedrite. very high values of au (39 ppm) and ag (>300 ppm) were found in this tetrahedrite (table 1). standard trace element analysis including 22 elements shows the presence of only 10 elements (rb, ta, u, zr, y, mo, pb, bi, sr and ba) in tetrahedrite, while 12 of them (be, sc, cs, ga, hf, nb, sn, th, v, w, tl and se) were below mdl (table 2). the total sum of the rare earth elements (ree) in the studied tetrahedrite is only 15.03 ppm although all 14 ree were analysed (table 3). la shows by far the highest concentration (10.6 ppm) and the ratios of lan/ybn (27.11) and σlree / σhree (5.530) indicate enrichment of the total lree against the total hree. but, excluding la, the lreen are depleted with regard to the hreen as clearly shown in the plot of ree normalized to ci chondrite values (sun & mcdonough, 1989) presented in fig. 2. the ree pattern is characterized by a pronounced positive eu anomaly (eu/ eu* = 2.48) and expressed as a negative ce anomaly (ce/ ce* = 0.220). the δ34scdt value of the investigated tetrahedrite sample is strongly negative: –11.8‰. (table 4). 5.2. barite table 2 presents the values of 30 analysed trace elements of both barite samples (vag and duv) taken from the duboki vagan barite deposit. the group of elements between be and y consist of 17 elements but only ni, hf, ta, w and y were detected in both barite samples. additionally, ga, u and zr were also found in the vag sample. the values of 8 other trace elements of this group (be, co, sc, cs, nb, sn, th and v) were below the mdl. the total content of the be-y trace element group is very low in both barite samples (<24.8 ppm in the vag sample and <16.2 ppm in the duv sample). in the second group of 13 trace elements between mo and se only 5, (cu, zn, as, sb and hg) were detected in analyses of both barite samples. pb and tl were only found in the vag sample, while au (0.9 ppb) is present only in the table 1: quantitative chemical analyses of fresh and weathered hg-tetrahedrites (d-vagt) from the duboki vagan barite deposit expressed in wt. %. abbreviations: n.a. – not analysed; ree – rare earth elements; tr. el – other trace elements; m.a. – mechanical admixtures. column 2 – anaysis of the hg-tetrahedrite in the sample d-vagt. column 3 – recalculated analysis from the column 2 (elimination of the mechanical admixture).     d-vagt d-vagt   tetrahedrite tetrahedrite mechanical admixtures       in tetrahedrite   jurković et al., 1997 this work this work   wt.% wt.%   wt.% cu 37.93 36.860 caco3 1.3734 fe 1.09 0.520 baso4 1.2970 zn 4.69 4.130 srso4 0.0470 cd n.a. 0.031 pb 0.0200 ag 0.13 >0.030 hg 2.45 3.795 total 2.7374 ni n.a. 0.027 co n.a. 0.006 w n.a. <0.005 sn n.a. ppm <1.0 sb 24.75 15.760 as 1.41 1.510 bi 0.20 0.147 tot/s 25.05 16.80 se n.a. ppm <0.5 au ppm 0.0154 ppm 0.0039 tot/c n.a. 0.61 po43n.a. 0.0399 ree n.a. 0.0015 tr. el. n.a. 0.0010 m.a. n.a. 2.7374 total 98.3104 100.2159 jurković et al.: geochemical characteristics of mercurian tetrahedrite, barite and fl uorite from the duboki vagan, glumac... geologia croatica 53 table 2: trace element content of hg-tetrahedrite (d-vagt) and barite (vag, duv and k-glu) from the barite deposits, south of kreševo. d-vagt, vag and duv samples are from the duboki vagan deposit, while k-glu sample is from the glumac deposit. data for k-glu sample are from jurković et al. (2010). all values are in ppm, except those of au, which are in ppb. d-vagt vag duv k-glu d-vagt vag duv k-glu elem. tetrah. barite barite barite elem. tetrah. barite barite barite   this work this work this work jurković et. al., 2010   this work this work this work jurković et. al., 2010   ppm ppm ppm ppm   ppm ppm ppm ppm be <1.0 <1.0 <1.0 <1.0 mo 137.4 <0.1 <0.1 0.2 co 63.5 <0.2 <0.2 0.3 cu 368600.0 2.5 66.0 3.9 ni 266.2 5.1 0.5 3.9 pb 1464.0 0.5 <0.1 2.4 sc n.a. <1.0 n.a. n.a. zn 41300.0 6.0 2.0 6.0 cs <0.1 <0.1 <0.1 0.1 as 15100.0 87.8 13.2 <0.5 ga <0.5 0.5 <0.5 <0.5 cd 313.6 <0.1 <0.1 <0.1 hf <0.1 1.1 0.9 0.5 sb 157600.0 1.9 1.0 0.3 nb <0.1 <0.1 <0.1 <0.1 bi 1466.0 <0.1 <0.1 <0.1 rb 0.2 <0.1 <0.1 0.4 ag >300.0 <0.1 <0.1 <0.1 sn <1.0 <1.0 <1.0 <0.1 au ppb 38963 ppb<0.5 ppb 0.9 ppb <0.5 ta 0.3 2.8 1.9 1.4 hg 37950.0 0.6 0.4 0.2 th <0.2 <0.2 <0.2 <0.2 tl <0.1 1.7 <0.1 <0.1 u 2.3 0.3 <0.1 <0.1 se <0.5 <0.5 <0.5 <0.5 v <8.0 <8.0 <8.0 13.0 total 663194.6 101.0 82.6 13.0 w <0.5 1.5 0.5 <0.5 sr 224.1 11965.0 11114.0 14354.0 zr 0.2 0.6 <0.1 1.6 ba 7632.0 >50000 >50000 >50000 y 7.1 1.2 1.0 1.0 ca 5500.0 n.a. n.a. 300.00 total 339.8 13.1 4.8 19.2           fi gu re 2: plot of ci chondrite-normalized ree abundances (sun & mcdonough, 1989) of hg-tetrahedrite (d–vagt) from the duboki vagan barite deposit. duv sample. there were 5 trace elements (mo, cd, bi, ag and se) below the mdl. the total sum of the trace elements of the mo-se group in the vag sample is <102.41 ppm where as (87.8 ppm) dominates. in the duv sample the total sum of the same elements is <84.58 ppm, but here cu (66.0 ppm) dominates. the analysed ree in barite are characterized by extremely low values: 7.77 ppm in total in the vag sample and 7.98 ppm in total in the duv sample (table 3). the lan/ybn ratio in the vag sample corresponds to 7.18, and the σlree / σhree ratio is 0.63, whereas in the duv sample the same ratios are 47.03 and 1.58 respectively. the values for nd and sm in both samples, and also the value of dy in the duv sample, were below the mdl. therefore the values of the eu anomaly (eu/eu*) could not be calculated. however, it is obvious from the plot of the ree pattern normalized to ci chondrite (sun & mcdonough, 1989) that both samples have pronounced positive eu anomalies because of the extremely low concentration of sm (fig. 3). the expressed negative ce/ce* anomaly is visible in both samples (where ce/ce* = 0.220 in the vag sample and 0.440 in the duv sample). the wt.% of srso4 in barite varies in the vag sample from 2.51 to 3.42 (thin fi ne grained and thick tabular coarse grained habits of barite crystals of the same sample) and in duv sample equates to 2.33 (table 4). the δ34scdt value of barite (duv sample) is +10.4‰, while the δ18osmow values of barite in the vag and duv samples are +15.6 and +17.3‰ respectively (table 4). 6. discussion in this section, these results will be compared with those from previously published papers concerning fl uid inclusion geologia croatica 64/1geologia croatica 54 fi gu re 3: plot of ci chondrite-normalized ree abundances (sun & mcdonough, 1989) of barites (vag, duv and k-glu) from the duboki vagan and glumac barite deposits. data for the k-glu sample are from jurković et al. (2010). table 3: rare earth element (ree) abundances of hg-tetrahedrite (d-vagt), and barites (vag, duv, k-glu) in comparison to ree abundances of ci chondrites (sun & mcdonough, 1989; palinkaš & jurković, 1994). data for sample k-glu are from jurković et al. (2010). the data for fl uorites (dd-fa and dd-fb) are from palinkaš & jurković (1994). diff erent parameters of hg-tetrahedrite (d-vagt), barites (vag, duv and k-glu) and fl uorites (dd-fa and dd-fb) are presented in the lower part of the table 3. data for sample k-glu are from jurković et al. (2010). data for two fl uorite samples (dd-fa and dd-fb) are from palinkaš & jurković (1994). all values are in ppm.   d-vagt vag duv k-glu ci dd-fa dd-fb ci ree tetrah. barite barite barite chondrite fl uorite fl uorite chondrite   this work this work this work jurković et al., 2010 sun & mcdonough, 1989 palinkaš & jurković, 1994 palinkaš & jurković, 1994 palinkaš & jurković, 1994   ppm ppm ppm ppm ppm ppm ppm ppm la 10.60 1.60 3.90 2.40 0.2370 0.0230 0.0293 0.3110 ce 1.10 0.20 0.50 0.90 0.6120 n.d. n.d. 0.8080 pr 0.14 0.03 0.02 0.10 0.0950 n.d. n.d. 0.1220 nd 0.60 <0.30 <0.30 0.30 0.4670 n.d. n.d. 0.6000 sm 0.12 <0.05 <0.05 0.45 0.1530 0.1200 0.1500 0.1950 eu 0.20 3.02 0.77 0.85 0.0580 0.0237 0.0247 0.0735 gd 0.51 1.69 1.77 1.02 0.2055 n.d. n.d. 0.2590 tb 0.08 0.10 0.15 0.08 0.0374 0.0230 0.0259 0.0474 dy 0.63 0.23 <0.05 2.78 0.2540 n.d. n.d. 0.3220 ho 0.16 0.23 0.29 <0.02 0.0566 0.1900 0.1100 0.0718 er 0.52 0.43 0.43 0.03 0.1655 n.d. n.d. 0.2100 tm 0.05 0.03 0.04 0.02 0.0255 0.0228 0.0450 0.0324 yb 0.28 0.16 0.06 0.07 0.1700 n.d. n.d. 0.2090 lu 0.04 0.05 0.05 <0.01 0.0254 0.0242 0.0210 0.0322 σree 15.03 7.77 7.98 9.00 2.562 0.4267 0.4059 3.2923 σlree 12.56 1.83 4.42 4.15   0.1797 0.2299 σhree 2.27 2.92 2.79 4.00   0.2370 0.1760 σlree/σhree 5.53 0.63 1.58 1.04   0.8004 1.3063 σreem/σreech 5.87 3.03 3.12 3.51   0.2665 0.1565 lan/ybn 27.11 7.18 47.03 24.71   tmn/smn 2.51   0.27   0.1587 1.8045 eu3+/eu2+ 2.48   3.84   ce4+/ce3+ 0.22 0.22 0.44 0.45   studies (palinkaš, 1988; palinkaš & jurković, 1994), sulphur, carbon and oxygen isotope compositions (šiftar, 1988; jurković et al., 1997; jurković & palinkaš, 2002; jurković et al., 2010) and ree analysis (palinkaš & jurković, 1994; jurković et al., 2010) in barite deposits of the mbsm and seb. 6.1. hg-tetrahedrite hg-tetrahedrite from the duboki vagan and dubrave-dugi dol barite deposits is mercury-bearing cu-sb-zn tetrahedrite, characterized by strongly negative δ34scdt values (table 4). similar δ34scdt values (–12,82; –10,18; –7.91; –9.50; –10.69; –9.68; –12.77; –11.00; –12.40; –10.92; –6.96; –11.43; –5.50; –10.91; –8.20; –8.79; –15.40; –13.74 ‰) corresponding to an average of –10.49 ‰ have been found in all studied samples of hg-tetrahedrite in the mbsm (jurković et al., 1997). in the seb, only one hg-tetrahedrite has been analyzed (fočanska jabuka) and its δ34scdt value equates to –4.95‰ (halamić et al., 1987; jurković et al., 2010). very high values for gold and silver were determined in the studied hg-tetrahedrite, where 39 ppm au and >300 ppm jurković et al.: geochemical characteristics of mercurian tetrahedrite, barite and fl uorite from the duboki vagan, glumac... geologia croatica 55 ag is a typical, genetically very important characteristic of all mbsm hg-tetrahedrites (jurković et al., 1997; jurković et al., 2010). in a tetrahedrite sample from the duboki vagan deposit analysed earlier (jurković et al., 1997), 1290 ppm ag was obtained (table 1). comparing the analyses of both duboki vagan tetrahedrite samples, (the fi rst analysed in 1997 and the second from the present study), it is obvious that they are very similar in cu, fe, zn and as values. the analysis performed here demonstrates that sb, hg and s are the most rapid weathering components of hgtetrahedrite (table 1). the analysed tetrahedrite displays the pronounced positive eu anomaly (eu/eu* = 2.480). according to bau (1991), bilal (1991) and bau & möller (1992) such a positive eu anomaly indicates ree mobilisation by a f–, oh– and co3 2–-fl uid in a high-temperature regime. such regimes have already been proven in the mbsm by palinkaš & jurković (1994), jurković & palinkaš (2002) and jurković et al. (2010). the eu3+/eu2+ ratio in aqueous solutions depends on pressure, ph and ree speciation, but the most important parameter is temperature (svjerensky, 1984; wood, 1990, 1990a; bau, 1991; hendtable 4: sulphur, carbon and oxygen isotope compositions of hg-tetrahedrites (d-vagt, dv-t1, dv-t2, dd-t1 and dd-t2, k-vdt1, k-vdt2, k-vdt3), barites (vag, duv, barite-1, barite-2, dd-b1, dd-b2 and k-glu, k-vdb1, k-vdb2) and calcite (dd-c, k-vdc1, k-vdc2) as also srso4 content of barites from the duboki vagan, dubrave-dugi dol and glumac barite deposits.     sample mineral srso4 (%) δ34scdt (‰) δ13 cpdb (‰) δ18osmow (‰) d ub ok i v ag an th is w or k d-vagt tetrahedrite   –11.80     vag barite 2.51; 3.42 15.60 duv barite 2.33 10.40 17.30 d ub ok i v ag an ju rk o vi ć et a l., 1 99 7 dv-t1 tetrahedrite   –6.96     dv-t2 tetrahedrite   –11.43 barite-1 barite 4.40 8.20 barite-2 barite 3.60 8.90     d ub ra ve -d ug i d ol dd-t1 tetrahedrite   –5.50     dd-t2 tetrahedrite   –10.91 dd-b1 barite 4.40 11.35 dd-b2 barite 6.10 11.02 23.09 dd-c calcite     –2.62 g lu m ac th is w or k k-glu barite 3.03 10.80   19.70  g lu m ac vi di ći ju rk o vi ć et a l., 2 01 0 k-vdb1 barite 6.60 9.03 k-vdb2  barite 5.70 9.88 k-vdt1  tetrahedrite –8.21 k-vdt2  tetrahedrite –8.79 k-vdt3  tetrahedrite –15.40     k-vdc1 calcite –2.43 22.41 k-vdc2 calcite –2.46 22.45 erson, 1984, 1996; gieré, 1996). in natural aqueous systems the occurrences of eu anomalies are due to the redox reaction: 2eu3+ + 2oh– = 2eu2+ + h2o + 0.5o2 (bau & möller, 1992). in general, negative ce anomalies are characterized by oxidizing conditions. a negative ce anomaly appears to be a function of o2 and ph, but is more sensitive to ph than to o2. in natural aqueous systems, the occurrences of ce anomalies are due to the redox reaction: 2ce3+ + 0.5o2 + 3h2o = 2ceo2 + 6h+ (bau & möller, 1992). the generation of ce anomalies in a high-temperature environment seems unlikely, because with increasing temperature, the ce4+/ce3+ redox equilibrium shifts toward higher fo2. according to wood (1990, 1990a), with increasing temperature both the ce4+/ce3+ ratio and the ce complex formation constants increase. 6.2. barite the srso4 content in the barite crystal lattice ranges between 2.33 and 3.42 wt.%. the srso4 contents of two barite samples obtained from the duboki vagan deposit by šiftar geologia croatica 64/1geologia croatica 56 (1988) and jurković et al. (1997) were 4.4 and 3.6 wt.%. barite from the glumac deposit (k-glu sample) contained 3.03 wt.% (jurković et al., 2010), while barite from the dubrave-dugi dol barite deposits has 4.4 and 6.1 wt.% srso4, and barite from the glumac–vidici deposit is composed of 6.60 and 5.70 wt.% srso4 (jurković et al., 1997) (table 4). such srso4 values in analysed barites are in accordance with the other 108 previously analysed barite samples from the mbsm, which contain on average 4.22 wt.% srso4 and are of hydrothermal origin (jurković & palinkaš, 1999). so far, only one ree analysis was performed on the mbsm barites, which was the analysis of the k-glu sample from the glumac barite (jurković et al., 2010). the two new ree analyses performed here on the duboki vagan barite samples (vag and duv) produced almost identical results, despite the fact that there are small differences in mineral paragenesis. it has to be stressed that the δ34scdt value obtained from the analyzed barite (+10.40‰) corresponds well with earlier published data of δ34scdt values in barite (+10.11‰ on average) and is typical for permian seawater (table 4). the analyzed δ18osmow values (n=3) in the barites of duboki vagan (+15.6 and +17.3‰) together with the previously published δ18osmow value (19.70‰) in the barite of glumac (jurković et al., 2010) illustrate that heightened δ18osmow values are typical for hg-tetrahedrite and octahedral fl uorite-bearing barite deposits located in the mbsm (jurković et al., 2010). 6.3. fluorite in order to compare the ree distribution pattern in barite and tetrahedrite analysed here with those in fl uorite published by palinkaš & jurković (1994) in the dubravedugi dol barite deposits, the plot of ree distribution in fl uorite normalized to ci chondrite is shown in fig. 4. the fl uorite crystals (dd-fa and dd-fb) studied by palinkaš & jurković (1994), show extremely low ree values of 0.427 and 0.406 ppm respectively. such fl uorites, with a total ree content of about only half that of chondrites, were reported by möller & morteani (1983) and eppinger & cloos (1990) from limestones in the alps, spain, morrocco and the usa. möller & morteani (1983) maintain that these fl uorites have been formed under hypersaline conditions or in evaporating basins. schneider et al. (1975), investigating fl uorite in the northern calcareous alps, also reported extremely low total ree values of 0.17, 0.57 and 0.72 ppm. the lan/ybn ratios of the fl uorite samples from the dubrave-dugi dol barite deposits (0.112 and 0.139 respectively), refl ect an enrichment of the hree over lree (table 4, fig. 4). according to ekambaran et al. (1986), and eppinger & cloos (1990), such a ree pattern indicates the late-stage formation of fl uorites. the formation of barite and fl uorite took place under opposing environmental conditions. the ce anomalies, although less pronounced, are also of opposite character. the increased sm values and decreased tm values in the tmn/smn ratios are, according to bowers & helgeson (1983) and wendlandt & harrison (1979), usual for fl uids supersaturated with respect to co2 and halides. schneider et al. (1975, 1977), and möller et al. (1976), distinguish fl uorite of hydrothermal and sedimentary origin, on the basis of the tb/ca atom ratio and the tbn/lan ratios. tbn/lan–tb/ca ratios for the fl uorites from the dubrave-dugi dol barite deposits (palinkaš & jurković, 1994), plot into the “sedimentary fi eld” according to schneider et al. (1975, 1977). in contrast, barites, as evidenced by their 87sr/86sr ratios are of hydrothermal origin. these data support the idea that barite on the one hand, and hg-tetrahedrite (±octahedral fl uorite) on the other, have been formed at different times and in dissimilar environments. a tb/la ratio >1.0 indicates late stage formation from a mineralization solution. the enrichment of the mree and hree relative to the lree may have been due to the formation of their stable f– and co3 2– complexes. the fl uid inclusion study of fl uorite suggets a very high homogenization temperature (th=250–330°c) with noticeable evidence of boiling and high salinity, (over 20 wt.% nacl equivalent). massive decrepitation started above 330°c (palinkaš & jurković, 1994). in the fl uorite-barite deposit of žune, ljubija, nw bosnia, fl uid inclusions in fl uorites distinguish even clear boiling processes and high salinity (palinkaš, 1988). 6.4. origin of barite deposits in the mbsm and seb according to jurković et al. (2010), two paragenetic types of barite deposits have been formed in the mbsm and seb during two mineralization phases. the fi rst, (older) phase, took place during the early permian (cisuralian), and produced veiny and metasomatic barfi gu re 4: plot of chondrite-normalized ree abundances of fl uorites (dd– fa and dd–fb) from the dubrave-dugi dol barite deposits (from palinkaš & jurković, 1994). jurković et al.: geochemical characteristics of mercurian tetrahedrite, barite and fl uorite from the duboki vagan, glumac... geologia croatica 57 ite deposits with subordinate or scarce fe, cu, zn, pb and sb sulphides and sulphosalts. these had positive δ34scdt values (±0 to +5‰), with some siderite and quartz as gangue minerals. this paragenetic type of barite deposits formed throughout the mbsm and also in the prača-foča region of the seb, and in the jajce-jezero region (the outermost nnw part of the mbsm). the best example of this type of barite deposit is the thoroughly studied trošnik ore deposit near fojnica (mbsm), which formed as irregular metasomatic bodies and veins within the lower palaeozoic dolomite (jurković, 1958; jurković et al., 1997). quartz, siderite and barite are the main gangue minerals. pyrite and chalcopyrite are the main ore minerals, whereas tetrahedrite is subordinate. all sulphides are characterized by positive δ34scdt values. three tetrahedrite samples from the trošnik ore deposit produced +3.24‰ and +3.73‰ (kubat et al., 1979/80) and +4.00‰ values (jurković et al., 2010). tetrahedrite from the trošnik deposit contains only traces of mercury (<0.20% and 0.03% according to jurković et al., 1997), and is formed by hydrothermal fl uid from the same sulphur source, as for pyrite and chalcopyrite in the same paragenesis. this fact indicates that the trošnik ore deposit has suffered a negligible overprint during a later phase. the second (younger) mineralization phase took place at the end of the permian (permian–triassic boundary), when early intracontinental rifting started. this period was characterized by heating, dilatation and fracturing of the greater part of the mbsm, enabling the rise of mercury, fl uorine and h2s from the upper mantle. karamata et al. (1995), published the highest concentration of mercury in the dinarides which occurred in the lower and middle triassic. the sulphides and sulphosalts formed during the fi rst mineralization phase were regenerated, remobilized, partly and/or completely fl uidized and reacted with ascending mercury and sulphur from the new source. these processes led to formation of the only hg-tetrahedrite characterized by negative δ34scdt values, ranging between –4.95‰ and –15.4‰ and also of high-temperature octahedral fl uorite. the rifting overprint (impact metasomatism) occurred very irregularly and with very differing intensity in various parts of the mbsm, seb and jajce-jezero areas. the most strongly affected areas were probably fault zones of the fi rst and second order, and zones warmed by magmatic eruptions. the most intensive processes and overprinting took place in the rostovo, gornji vakuf and kreševo areas, whereas a very weak overprint occurred in se bosnia. barite formed during the fi rst mineralization phase underwent strong heating and a change of pressure and f(o2) in the environment during the later second phase. these events are refl ected in the shift of δ18osmow values toward higher values, and δ34scdt values toward lower values in barite (jurković et al., 2010). sulphide-bearing barites from seb which are weakly overprinted, and have δ18osmow values within a narrow range (+14.6‰ to +15.6‰), whereas barite samples with hg-tetrahedrite and fl uorite from the mbsm, reveal higher δ18osmow values ranging from +15.6 to +22.4‰. the sulphur isotopes (δ34scdt) in the barites from the seb span a range from +11.6 to +17.7‰ (mean +16.4‰). barites from the mbsm also display a narrow range of δ34scdt values between +10.1‰ to +16.8‰, but with a signifi cantly lower mean value of +11.8‰ (jurković et al., 2010). the most pronounced result is a very expressive positive eu anomaly in all the overprinted barite samples, which suggests a high-temperature mineralizing fl uid. in the fočanska jabuka deposit (seb), two different mineralization phases are very clearly distinguished in time. in the older (lower permian) phase, barite, quartz, siderite deposits formed with pyrite, chalcopyrite and galena ore minerals kubat et al. (1979/1980) found that the δ34scdt values of sulphides are +2.80‰ in pyrite, +2.49‰ in chalcopyrite and +3.04‰ in galena. jurković et al. (2010) determined δ34scdt (+17.7%o) and δ18osmow (+15.1‰) values in barite. the ore body is transected by a younger barite vein containing even younger hg-tetrahedrite veinlets characterized by a strongly negative δ34scdt value –4.95‰ in a later mineralization phase (halamić et al., 1987). 7. conclusion a broad comparison of geochemical data was undertaken of barite deposits associated with subordinate or scarce fe, cu, zn, as and sb sulphides and sulphosalts, characterized by a positive δ34scdt value (±0 to +5‰) with barite deposits where hg-tetrahedrite, as the only sulphide mineral, was characterized by negative δ34scdt values (–4.95 to –15.4‰) and which is locally associated with high-temperature octahedral fl uorite. the following facts and data were established as a result: 1) both paragenetic barite types are contemporaneous and have an epigenetic hydrothermal origin. they also share almost the same 87sr/86sr ratio, (the difference is only 0.0041), and very similar ree contents (on average 7.1 and 8.3 ppm respectively). the most pronounced difference between the two paragenetic types is observed in the oxygen isotopic com position of the barites. polysulphide-bearing barites show a δ18osmow value within a narrow range (+14.6‰ to +15.6‰), whereas hg-tetrahedrite bearing barites have δ18osmow values ranging from +15.6 to +22.4‰. differences in the sulphur isotope composition have also been noted, but are inexplicable. 2) a new sulphur source was vital for formation of the hg-tetrahedrite (schwazite). most probably, it was h2s that ascended from the upper mantle during early intercontinental rifting and/or organic sulphur being formed in the ores and rocks of completely different sedimentary environments. 3) the octahedral, high temperature fl uorite occurs only in the hg-tetrahedrite-bearing barite deposits. it is characterized by extremely low ree contents, a low lan/ybn ratio indicating a very distinct enrichment of hree and late stage formation of fl uorite. 4) a very low ree (0.4 to 0.45 ppm) content indicates the formation of fl uorite under hypersaline conditions or in evaporating basin. increased values for sm and decreased values for tm in the smn/tmn ratios, characterize fl uids supersaturated with respect to co2 and halides. geologia croatica 64/1geologia croatica 58 5) tbn/lan–tb/ca atom ratios of fl uorites from the dubrave-dugi dol barite deposits plot in the sedimentary fi eld of schneider et al. (1975, 1977), while all barites have a hydrothermal origin. this indicates great differences in the timing and environmental circumstances of barite and fl uorite formation. 6) all the described events are effects of the early intercontinental rifting which took place between the uppermost permian and lower triassic. concerning the strength and intensity of this geological event, it affected separate parts of the mbsm and seb in very different ways. the most important event was the ascension of mercury, fl uorine, boron and sulphur from the upper mantle, and very strong heating and tectonization. these circumstances enabled remobilization and partial fl uidization of primary fe, cu, zn, sb and pb sulphides and their reaction with the ascended mercury and sulphur, followed by formation of octahedral fl uorite, tourmalinization and large, local masses of calcite. in a single case (fočanska jabuka) a new barite body was formed in this younger phase containing one even younger hg-tetrahedrite vein, characterized by a strongly negative δ34scdt value –4.95‰. 7) the duboki vagan barite deposit, together with in this work compared the glumac and dubrave-dugi dol barite deposits originated in the late variscan (lower permian). early intercontinental rifting in the post variscan (early eoalpine phase), triggered processes that caused the shift of barite δ18osmow values, remobilization and partial fl uidization of primary polysulphides and formation of hgtetrahedrite as the only ore mineral with octahedral fl uorite. references bau, m. (1991): rare-earth element mobility during hydrothermal and metamorphic fl uid-rock interaction and their signifi cance of the oxidation state of europium.− chem. geol., 93, 219−230. bau, m. & möller, p. (1992): rare earth element fractionation in metamorphogenic hydrothermal calcite, magnesite and siderite.− miner. petrol., 45, 231−246. bilal, b.a. (1991): thermodynamic study of eu3+/eu2+ redox reaction in aqueous solutions at elevated temperatures and pressures by means of cyclic voltammetry.− z. naturforsch. a., 46, 24/91/011, 1108−1116. bowers, t.s. & helgeson, h.c. (1983): calculation of the thermodynamic and geochemical consequences of nonideal mixing in the system h2o-co2-nacl on phase relations in geologic systems: metamorphic equilibria at high pressures and temperatures.− am. mineral., 68, 1059−1075. conrad, a. (1870): bosnien mit bezug auf seine mineralschätze.− mitt. osterr.geogr. g., 219 p. duda, r., rejl, l. & slivka, d. (1987): la grande encyclopédie des minéraux.− librairie gründ, paris, 520 p. ekambaran, v., brookins, d.g., rosenberg, ph.e. & emanuel, k.m. (1986): rare-earth element geochemistry of fl uoritecarbonate deposits in western montana, usa.− chem. geol., 54, 319−331. eppinger, r.g. & cloos, g.l. (1990): variation of trace elements and rare earth elements in fl uorites. a possible tool for exploration.− econ. geol., 85/8, 1896−1907. gieré, r. (1996): formation of rare earth minerals in hydrothermal systems.− in: lipin, b.r. & mckay, g.a. (eds): geochemistry and mineralogy of rare earth elements, reviews in mineralogy, 21, mineralogical society of america, 105−150. halamić, j., karan, d. & vlah, g. (1987): pojave auripigmenta i antimonita u naslagama gipsa kod jabuke (foča–jugoistična bosna) [auripigment and antimonite occurrences in gypsum layers at jabuka (foča-se bosnia) – in croatian].− geološki glasnik, 31−32/ 2–3, 186–194. henderson, p. (1984): developments in geochemistry.− in: henderson, p. (ed): rare earth element geochemistry, elsevier, amsterdam, 510 p. henderson, p. (1996): the rare earth elements: introduction and review.− in: lipin, b.r. & mckay, g.a. (eds): geochemistry and mineralogy of rare earth elements reviews in mineralogy, 21, mineralogical society of america, 1−18. herbich, f. (1880): vergl. erhebungen und vorstudien über den mettalbergbau in bosnien.− neues jb. miner. etc. ii, stuttgart, 94 p. herbich, f. (1880a): geologishes aus bosnien-herzegovina.– neues jb. miner. etc., stuttgart, 94–96. jeremić, m. (1963): metalogenija paleozojskih ležišta barita bosne [metalogenesis of palaeozoic barite ore deposits of bosnia – in croatian].− technologica acta i, 1−2, phd thesis, tuzla, 60 p. jovanović, r., mojičević, m., tokić, s. & rokić, lj. (1977): osnovna geološka karta, m 1:100 000, list sarajevo, k-34-1 [basic geological map of sfry 1:100000, sarajevo sheet – in croatian].− savezni geološki zavod, beograd. jovanović, r., mojičević, m., tokić, s. & rokić, lj. (1978): osnovna geološka karta, m 1:100 000, tumač za list sarajevo, k-34-1 [basic geological map of sfry 1:100000, sarajevo sheet – in croatian].− savezni geološki zavod, beograd, 45 p. jurković, i. (1956): mineralne parageneze srednjobosanskog rudogorja s osobitim osvrtom na tetraedrite [mineral parageneses of the mid–bosnian ore mountains with particular respect on tetrahedrites – in croatian].− phd thesis, university of zagreb, 306 p. jurković, i. (1958): tetrahedrite from the ore deposit of trošnik near fojnica in the mid–bosnian ore mountains− geološki glasnik, sarajevo, 4, 221–246. jurković, i. (1986): quantitative chemical and optical investigations of the tetrahedrite from barite-bearing deposit vidici on the northern slopes of the mešuvršje south of the town of kreševo, bosnia.− geološki vjesnik, zagreb, 39, 187–224. jurković, i. (1987): barite deposits on mount međuvršje south and south-east of the town of kreševo, bosnia.− geološki vjesnik, zagreb, 40, 313−336. jurković, i. (1988): ore deposits in the duboki vagan region, south and south-west of the town of kreševo, bosnia.− geološki vjesnik, zagreb, 41, 355−367. jurković, i. & miko, s. (1997): tetrahedrite from the dubrave-dugi dol deposits, kreševo, bosnia and herzegovina.− rud.-geol.naftni zbornik, zagreb, 9, 11−16. jurković, i. & palinkaš, l.a. (1999): sulphur isotope and fl uid inclusion data of barites from the dinarides. 6th biennal meeting of sga and iagod. mineral deposits, porcesses to processing, london, 1999.− proceeding, balkema publ., rotterdam, 45−49. jurković, i. & palinkaš, l.a. (2002): discrimination criteria for assigning ore deposits located in the dinaridic paleozoic-triassic formations to variscan or alpidic metallogeny.− in: blondell, d.j., neubauer, f. & quade, a. (eds): the timing and location of the major ore deposits in a orogen. geological society, london, special publications, 204, 229−245. jurković, i., garašić, v. & hrvatović, h. (2010): geochemical characteristics of barite occurrences in the paleozoic complex of south-eastern bosnia and their relationship to the barite deposits of the mid-bosnian schist mountains.− geol. croat., 63/2, 241−258. jurković et al.: geochemical characteristics of mercurian tetrahedrite, barite and fl uorite from the duboki vagan, glumac... geologia croatica 59 jurković, i., ferenčić, a., gregl, r., jakovljević, m., kučar, a. & tribuson, b. (1951): geological map, m 1:25 000 of the kreševo, dusina and deževice area, published partially by jurković (1987). jurković, i., palinkaš, l.a., slovenec, d., šiftar, d., miko, s., jakšić, m. & pezdič, j. (1997): geochemical characteristics of mercurian tetrahedrites from the middle bosnian schist mountains.− in: papunen, h. (ed.): mineral deposits: research and exploration − where do they meet? proceedings of the 4th biennial sga meeting, turku, finland, 11−13 august 1997, a.a. balkema, rotterdam/brookfi eld, 829−833. karamata, s., ozerova, n.a. & janković, s. (1995): metallogenic aspects of mercury geochemistry in ore deposits of the central part of the balkan peninsula.− geological society of greece. spec. tubl. athens, 4, 741–746. katzer, f. (1907): die fahlerz und quecksilbererzlagerstätten bosniens und der herzegovina.− bergund hüttenmänisches jahrbuch d. montan. hochschule zu leoben u. pribram. wien, bd., 55. kubat, i., ramović, e., tomčević, d., pezdić, j. & dolenac, t. (1979/1980): the results of the investigation of s, o, c and pb isotopic composition in some ore deposits and occurre nces in bosnia and herzegovina.− geološki glasnik, 24/25, 61–84. mikolji, v. (1969): povijest željeza i željeznog obrta u bosni [the history of iron and iron trade in bosnia – in croatian].− metallurgic institute “hasan brkić”, zenica. möller, p. & morteani, g. (1983): on the geochemical fractionation of rare earth elements during the formation of ca-minerals and its application to problems of the genesis of ore deposits.− in: augustithis, s.s. (ed.): the signifi cance of trace elements in solving petrogenetic problems and controversis, theophrastus publ., athens, 747−791. möller, p., parekh, p.p. & schneider, h.j. (1976): the aplication of tb/ca-tb/la abundance ratios to problems of fluorspar genesis.− miner. deposita, 11/1, 111−116. palinkaš, l.a. (1988): geochemical characteristics of palaeozoic metallogenetic regions: samoborska gora, gorski kotar, lika, kordun and banija.− unpublished ph.d. thesis, university of zagreb, 108 p. palinkaš, l.a. & jurković, i. (1994): lanthanide geochemistry and fluid inclusion peculiarities of the fluorite from the barite deposits south of kreševo (bosnia and herzegovina).− geol. croat., 47/1, 103−115. sofilj, j., živanović, m & pamić, j. (1980): osnovna geološka karta, m 1 : 100.000, tumač za list prozor k-33-12 [basic geological map of sfry 1:100000, geology of the prozor sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd, 49 p. schneider, h.j., möller, p. & parekh, p.p. (1975): rare earth elements distribution in fl uorites and carbonate sediments of the east-alpine mid-triassic sequences in the nördliche kalkalpen.− miner. deposita, 10/1, 330−344. schneider, h.j., möller, p., parekh, p.p. & zimmer, e. (1977): fluorite contents in carbonate sequences and rare earths distribution in fl uorites of pb-zn deposits in east-alpine mid-triassic.− miner. deposita, 12/1, 22−36. sun, s.s. & mcdonough, w.f. (1989): chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes.− in: saunders, a.d. & norry, m.j. (eds.): magmatism in the ocean basins, geological society, special publication, 42, 313−345. svjerensky, d.a. (1984): europium redox equilibrium in aqueous solution.− earth planet. sci. lett., 67, 70−78. šiftar, d. (1988): kemijske značajke barita iz nekih ležišta u bosni [chemical characteristcs of barite from some ore deposits in bosnia – in croatian].− rudarsko-metalurški zbornik, ljubljana, 35/ 1–4, 75−89. vogt, f. (1880): nachtrag i zu den zitierten erhebung in vorstudien usw wien. walter, b. (1887): beiträge zur kenntniss der erzlagerstätten bosniens. wien, 182 p. wendlandt, r.f. & harrison, w.j. (1979): rare earth partitioning between immiscible carbonate and silicate liquids and co2 vapour: results and implications for the formation of light rare earthenriched rocks.− contrib. miner. petr., 69, 409−419. wolf, d. (1847): ansichten über die geognostisch montanistischen verhältnisse bosniens, graz. wood, n.a. (1990): the aqueous geochemistry of the rare earth elements and yttrium. 1. review of available low temperature data for inorganic complexes and the inorganic ree speciation of natural waters.− chem. geol., 82, 159−186. wood, n.a. (1990a): the aqueous geochemistry of the rare earth elements and yttrium. 2. theoretical prediction of speciation in hydrothermal solutions to 350°c at saturated water vapour pressure.− chem. geol., 88, 99−125. manuscript received july 02, 2010 revised manuscript accepted december 15, 2010 available online february 22, 2011 geologia croatica 45 183 184 zagreb 1992 mr. drago savić (1936 1992) j nakon duge i teške bolesti u zagrebu je 9. lipnja 1992.godine, preminuo mr sci. drago savić, dipl. ing. geologije. drago savić rođen je 12. 04. 1936. godine u mjestu ' brezov ljani u bosni i hercegovini. osnovnu školu je završio u rodnom mjestu, srednju tehničku geološkog smjera u beogradu, a studij geologije na prirodoslovno­ matematičkom fakultetu sveučilišta u zagrebu 1961. godine. na istom fakultetu magistrirao je 1981. godine. radom je započeo 1961. godine u bivšem institutu za naftu, a 1963. prešao je u institut za geološka istraživanja, gdje je radio do smrti. bilo je to vrijeme početka istraživanja za osnovnu geološku kartu. sudjelovao je na izradi listova u dinaridimadrvaru, udbini, varaždinu i ogulinu, te kao voditelj na listu' delnice. uz ova istraživanja, bavio se praktičnim, injženjerskim i hidrogeološkim istraživanjima na pr. vode u okolici cazina, barita u gorskom kotaru, sirovina za keramičku industriju itd. objavio je sam ili u koautorstvu 25 radova. referirao je na mnogim geološkim skupovima u bivšoj jugoslaviji te krakovu i trstu. godinama je bio na listovima osnovne geološke karte kao geolog s najvećim brojem opservacijskih točaka. to dovoljno govori o njegovom velikom entuzijazmu, a istovremeno i profesionalnom odnosu prema poslu i struci. takav drago savić ostaje u pamćenju svojih kolega geologa, prijatelja i rodbine. slava mu! momčilo milanović bibliografija rado v a mr. drage savića sastavite: blaženka magaš i blanka cvetko l. šušnjar, milan, bukov ac, josip, marinčić, stanko & savić, drago (1965):.stratigrafija gipsnih naslaga unske doline i korelacija s poznatim evaporitnim naslagama i popratnim faci j esima u primorju, dalmaciji, lici i zapadnoj bosni.acta geol., 5, (prir. istraž. jugosl.akad. znan. umjet., 35), 407-422, 8 sl., l karta,zagreb: 2. šušnjar, milan, bukovac, josip & savić, drago (1967):paleografski odnosi nakon taloženja anizičkih naslaga u području južne like. geol. vjesnik, 20 (1966), 191-198,3 sl., l prof., l karta. zagreb. 3. šušnjar, milan, bukov ac, josip, savić, drago & girmani, maja (1967):značaj nalaza senona i paleogena u području kulen v akufa za tretiranje odnosa u sedimentacionom bazenu dinarida. geol. vjesnik,20 (1966), 199-205, 2 sl., l prof .. , l geol. karta. zagreb. 4. šušnjar, milan, nikler, leon, crnolatac, ivan, milan, ante, šikić, drago, grimani, ivo, vulić, željko & blašković , ivan (1970): osnovna geološka karta sfrj-e. list crikvenica l : 100 000. l 33-102.inst.. geol. istraž .. , zagreb 1961-1969. sav geol. zavod, beograd. 5. razvoj jure i krede između gornjeg jelenja i grobničkog polja. -geol. vjesnik, 25 (1971), 127147, 7 tab., zagreb, 1973. 6. mamužić, pavao & milanović, momčilo (1973):lower cretaceous and upper malmian in the broader šain-kuti area (gorski kotar).bull. sci. acad. yougosl., 18n-9, 138-139, l sl., zagreb. 7. reverse-overhrust relations in the region of razloge and praport in gorski kotar, croatia, yougoslavia. -bull. sci. cons. acad. yougosl., (a), 2ln-9, 135, l sl., zagreb, 1976. 8. tectonic characteristic in the region between delnice, brod na kupi and skrad in croatia, yugoslavia. -bull. sci. cons. acad. yougosl., (a), 21/3-6,6770, l sl., zagreb,l976. 9. & milanović, momčilo (1979): malmske i donjokredne naslage šire okoline drage (slovenija). g eo l. vjesnik, 31,373-376, l sl. , zagreb. 184 10.& romandić sreten (1980): tektonski kontakt perm skih i dogerskih naslaga kod velike vode, gorski kotar (izvod iz referata).j ub. simp. '20 g. labor metode geol. kartiranja, str. 51, beograd. ll.& romandić sreten (198l):tektonski kontakt permskih i dogerskih naslaga kod velike vode (gorski kotar ). bilten 3, 275-282, labor. za metode geol. kartiranja, beograd. 12. problem tektonskog sklopa gorskog kotara. geol. vjesnik, 35, 87-92, 2 sl., zagreb, 1982. 13.dozet, stevo & s ark otić, milka (1982): odnos permskih i gornjotrijaskih naslaga na području gorskog kotara. lo jub. kongr. geol. jugosl., l, 653-675, 4 tab., budva. 14.& zelenik, mladen (1982): strukturno-geološke karakteristike šireg područja cazinske krajine.10. jub. kongr: geol. jugosl., l, 677-699,6 sl. bud va. 15. milanović, momčilo & sarkotić, milka (1983): the malmian terrigenous layers at kamenjak (gorski kotar). 4. intern. assoc. sediment., abstract, 152-154, split. 16.& dozet, stevo (1984): osnovna geološka karta sfrj l : 100 000. list delnice l 33-90. geol. zavod zagreb, geol. zavod ljubljana (1970-1983), sav. g eo l. zavod, beograd. 17. gorski kotar und kijak area on petrova gora baryte, croatiayugoslavia.world congr. non-metallic minerals summ., 2, 157-167, beograd, 1985. 18.& dozet, stevo (1985): osnovna geološka karta sfrj 1: 100 000. tumač za list delnice l 33geologia croatica 45 90.geol. zavod zagreb, geol. zavod ljubljana (1983), sav. geol. zavod beograd 66 str., beograd. 19. strukturno geološki-litološki sklop kvaliteta i prostorni položaj baritno-getitnih orudjenjenjajugoistočnog dijela petrove gore.ll. kon gr. g eo l. jugosl., 4, 425-440, tara, 1986. 20. -&hećimović ljerka (1986): telurno, elementarno željezo zapadno od suhe peme (petrova gora). ll. kongr. geol. jugosl., 4, 129-140, tara. 21.& sarkotić-šlat, milka (1986): channel turbidites of georgovo, gorski kotar.5. skup sedim. jugosl., abstracts, 110-114, brioni. 22. the tectonic units of gorski kotar at the northwest part of dinarides. -abstracts intern. symp. on the evolut. karstic carbonate platform: relation with other periadriatic carbonate platforms, 5455, trieste, 1987. 23. formiranje karbonatne platforme dinarida. geol. glasnik, posebna izd. 6, zbornik radova 6. skup sediment. jugosl., 207-219, titograd, 1988. 24. & koštić , jakov (1990): kinematski akt oblikovanja i hidrotermalne emanacije područja između vrginmosta i topuskog, kordun. jugosl. geol. kongr., 3, 829-837, 2 sl., ohrid. 25. milanović, momčilo & momćilović, nevenka (1990): strukturno-litološki sklop mineralne sirovine područja blizu vrginmosta­ kordun.-12. jugosl. geol. kongr., 3, 277-286, 2sl., ohrid.  1. introduction pennsylvanian (late carboniferous) coal-bearing deposits have been known in north-western turkey in the vicinity of zonguldak since the early 19th century (schlehan, 1852; spratt, 1877), and there were a number of early studies on the stratigraphy, including the plant biostratigraphy, notably by zeiller (1896, 1899) and ralli (1896). for many years, coal mining was on a relatively small scale and mainly by foreign companies, and it was not until the mines started to be nationalised in the mid-1930s (güney, 1967) that there was a marked expansion in geological studies (ralli, 1933; hartung, 1937; jongmans, 1939; grancy, 1939; arni, 1939); some background comments to these investigations can be found in wagner & van amerom (1995) and wagner (1997). plant biostratigraphy played a pivotal role in these studies, with numerous published species lists and in some cases specimens illustrated. after the 1939–1945 war, interest in the palaeobotany of these coal-bearing beds was continued mainly by jongmans (1955), and two of his students, egemen (1958, 1959) and wagner (in stockmans, 1962, p. 664, fig. 6). wagner (1984) made some brief comments on the turkish data in his seminal biostratigraphical analysis of carboniferous euramerican floras, and subsequently (in kerey et al., 1986) he made a more in depth analysis and figured several plant fossils. the stratigraphical sequence in the zonguldak – amasra coal basin has potentially much significance. if, as suggested by wagner (in stockmans, 1962), there is an essentially complete succession of namurian and westphalian strata here, it would potentially provide a key link between the successions of the caucasus and donets, and the rest of variscan euramerica (sensu cleal et al., 2010). moreover, cleal et al., (2010, 2011) have suggested that the progressive breakdown in the coal swamp biome in euramerica during westphalian times may have been initiated in the easternmost part of the area and a better understanding of how the zonguldak – amasra coal-bearing succession relates biostratigraphically to neighbouring areas will clearly be critical to understanding this major change in biotas and habitat. this paper will review the available published data on the distribution of plant macrofossils in the zonguldak – amasra coal basin and discuss the implications for the stratigraphic age of these deposits. ab stra ct the zonguldak – amasra coal basin in north-western turkey has carboniferous terrestrial deposits ranging in age from arnsbergian to late asturian or possibly early cantabrian. they yield macrofloras that allow detailed biostratigraphical correlations with sequences in europe. these correlations suggest there are substantial gaps in the zonguldak – amasra succession, with middle to upper namurian, upper langsettian, duckmantian and lower asturian strata apparently being missing. this in turn suggests the area was subjected to significant tectonic instability during pennsylvanian (late carboniferous) times and that this might have been instrumental in initiating the progressive change in composition and eventual collapse of the coal swamp biome across variscan euramerica during westphalian times. keywords: palaebotany, biostratigraphy, pennsylvanian, zonguldak-amasra coalfield a reappraisal of the carboniferous macrofloras of the zonguldak – amasra coal basin, north-western turkey  christopher j. cleal1 and isabel m. van waveren2 1 department of biodiversity & systematic biology, national museum wales, cathays park, cardiff cf10 3np, uk; (chris.cleal@museumwales.ac.uk) 2 naturalis, p.o. box 9517, 2300 ra leiden, the netherlands; (isabel.vanwaveren@ncbnaturalis.nl) doi: 104154/gc.2012.19 geologia croaticageologia croatica geologia croatica 65/3 283–297 7 figs. 4 tabs. zagreb 2012 geologia croatica 65/3geologia croatica 284 2. geological background the zonguldak – amasra coal basin is the primary source of hard coal in turkey, with proven reserves of 1.1 x 109 tonnes (i̇naner & nakoman, 2004). during the 19th century, this area was usually referred to as the heraclée or heraclea coal basin, after the port with the current written name of ereğli. nowadays, however, it is usually referred to as the zonguldak – amasra coal basin, after its two main coal mining towns (fig. 1), and this is the name that will be used in this paper. the basin was formed on part of the pontide block, a gondwana-derived microcontinent that had docked with baltica probably by ordovician times (kalvoda & bábek, 2010). the pontides formed a passive margin along this part of laurussia on which an essentially regressive sequence was deposited, with ordovician – silurian marine clastics, middle devonian – mississippian shallow marine limestones, and uppermost mississippian and pennsylvanian terrestrial deposits (yanev et al., 2006). the carboniferous terrestrial deposits, which lie conformably on the viséan marine limestones of the yılanlı formation, are about 2100 m thick and were derived from the laurussian landmass to the north (kerey, 1985). based on divisions introduced by ralli (1896, 1933) this terrestrial interval is usually divided into four formations, as summarised in table 1. 3. chronostratigraphy and biostratigraphy late carboniferous biotas were characterised by strong global provincialism, which was largely the result of latitudinal climatic zones (wagner, 1994). this has caused major problems with establishing global biostratigraphic correlations and consequently with developing a global chronostratigraphic scheme. recent improvements in the resolution of radiometric dating (davydov et al., 2010; schmitz & davydov, 2012; waters & condon, 2012) are now offering the potential of circumventing these biostratigraphical problems and a practical global chronostratigraphy for the carboniferous system may appear in the foreseeable future. for now, however, the currently accepted iugs global chronostratigraphy for the carboniferous (e.g. heckel & clay ton, 2006) remains a theoretical aim rather than a practical tool for the upper part of the system, at least outside of the low-latitude marine realm where the boundary stratotypes (gssps) of the stage boundaries are located; there remain, for instance, discrepancies between the biostratigraphical (e.g. kullmann et al., 2007) and radiometric (davydov et al., 2010; waters & condon, 2012) evidence for locating accurately the base of the iugs moscovian stage within the palaeotropical terrestrial sequences. figure 1: location of the zonguldak – amasra coal basin. the upper map shows the main localities in the basin, with a small inset showing their position relative to the black sea (redrawn from jongmans, 1955). bottom left is a simplified geological map of the zonguldak coalfield (redrawn from güney, 1967). bottom right is a simplified geological map of the amasra coalfield (redrawn from tokay, 1962). cleal and van waveren: a reappraisal of the carboniferous macrofloras of the zonguldak – amasra coal basin, north-western turkey geologia croatica 285 dix (1934, 1937) developed the first biostratigraphical scheme for carboniferous plant macrofossils using biozones, (in this case assemblage zones), that were defined independently of lithostratigraphy (burek & cleal, 2005). however, dix (1934, 1937) was rather ahead of her time and her scheme was not widely adopted outside of britain. it was not until wagner (1984) developed a comparable scheme to dix’s that carboniferous plant biostratigraphy took on a modern aspect. like dix’s scheme, wagner’s was based on biozones determined from range charts that showed the stratigraphical distribution of the species. this time, however, the data on which the zones were established were taken from across europe and north america, and so potentially the scheme should have wider application than dix’s. the zones were concurrent range zones although in a number of cases the boundary between zones was effectively made to coincide with chronostratigraphical stage / substage boundaries. according to wagner (1984) this made sense as many of the substage boundaries had been defined using macrofloral indices. the asturian and stratigraphically higher substages were indeed defined mainly using macrofloral indices as the faunal data from these strata tend to be limited and often equivocal (e.g. bouroz et al., 1972; laveine, 1977; wagner, 1998). however, the stratigraphically lower stages and substages were mainly defined on eustatic marine bands and/or changes in the faunas (waters, 2011), which tended to operate independently of the vegetation changes. consequently, by forcing the zonal boundaries to coincide with the substage boundaries, parts of the wagner (1984) biostratigraphical scheme did not reflect the actual pattern of change in the macrofloras as well as dix’s (1934, 1937) scheme. nevertheless, wagner’s (1984) scheme has become widely adopted in the literature. cleal (1991) modified several aspects of wagner’s (1984) scheme. greater emphasis was given to what defined the boundaries, rather than the content of the zones, therefore changing them into interval zones. also, a set of subzones was introduced based on some of the temporal changes in the coal swamp vegetation not reflected in the wagner (1984) scheme, notably those in the middle langsettian, middle bolsovian and upper asturian substages. this more detailed approach helped maintain the integrity of the widely used wagner (1984) biozones, whilst also incorporating some of the more “natural” features of the dix (1934) scheme. 4. palaeobotany the following analysis will mainly focus on the biostratigraphy and (for the kozlu formation) the species diversities of the plant fossils. as is normal in palaeobotanical studies, the fossils are named as fossil-taxa (sensu cleal & thom as, 2010a,b, mcneill & turland, 2011), which refer to remains of particular parts of the plant rather than whole organisms. using a similar approach to that advocated by cleal (2005, 2007) only the fossil-taxa for one plant part are listed for each plant group, mainly those of the foliage, except for the lycopsids in which the stem / bark fossil-taxa are given. 4.1. alacaağzı formation macrofloras are generally poor in this interval, and many of those that have been reported are difficult to place accurately in a stratigraphical context. however, zeiller (1899, p. 83), jongmans (1955, p. 58) and kerey et al. (1986, p. 205) have reported plant fossils from several localities in the zonguldak coalfield and small outcrops to the west (alacaağzı, kireçlik, teflenli). these plant beds all immediately overlie marine limestones presumably of the kokaksu “member” and so were probably in the gökgöl “member” (see table 1). these macrofloras are all similar and are summarised in table 2. fig. 2 shows the ranges of the stratigraphically most instructive species in the alacaağzı formation macrofloras plotted against the wagner (1984) / cleal (1991) biozones. this clearly indicates that the alacaağzı formation macrofloras belong to the lyginopteris stangeri zone, and probably the lower part of that zone. although not included in the taxonomic lists in table 2, jongmans (1955) repeatedly mentioned mesocalamites stems from these beds, table 1: lithostratigraphic divisions of the zonguldak – amasra coal basin, based on kerey (1982) and kerey et al. (1986). formation member facies palaeoenvironment thickness stratigraphical age kızıllı alternating coarse and fine clastic deposits; some thin coals, and red beds develop towards top of formation braided stream system in an intra-montane setting, becoming better drained towards top of section 280 m late westphalian karadon alternating coarse and fine clastic deposits; some coals, mainly in the lower part of the formation braided stream and alluvial fan 500 m middle westphalian kozlu dılaver alternating coarse and fine clastic deposits, with abundant coals fluvio-deltaic, floodplain 300–750 m early westphalian kılıç mainly lacustrine alacaağzı asma mainly sandstones terrestrial 600 m namurian tarlaağzi mixed coarse and fine clastics shallow marine gökgöl mixed coarse and fine clastics, with thin coals mainly terrestrial kokaksu limestones and clastic deposits mainly shallow-marine geologia croatica 65/3geologia croatica 286 which wagner (1984) again suggested is a characteristic taxon of the l. stangeri zone. similar l. stangeri zone macrofloras have been reported from the upper rakovski formation in the dobrudzha coal basin, bulgaria (kulaksazov & tenchov, 1973; tenchov, 2004) and the lower ostrava formation in upper silesia, czech republic (purkyňová, 1970). in western europe, such floras are poorly documented, although there are records from the upper limestone formation in scotland (walton et al., 1938). according to wagner (1984), this zone indicates a stratigraphical position in the lower namurian stage (arnsbergian substage) and thus a latest mississippian age. in the amasra area to the east, the alacaağzı formation is more marine in character (kerey, 1982; kerey et al., 1986) and plant remains are consequently rarer. however, low diversity macrofloras comparable to those of the gökgöl “member” have been reported from near güllük and dökök (charles, 1931; jongmans, 1955). wagner (1984) suggested there are even older macrofloras from the zonguldak area, belonging to the neuropteris antecedens zone, which would indicate a late viséan or earliest namurian age. wagner referenced jongmans (1955) for this opinion, but there is nothing recorded in this latter paper to support such a view. since the gökgöl “member” represents the stratigraphically oldest extensive terrestrial deposits in the coalfield, older macrofloras from here would seem to be unlikely. wagner (in stockmans, 1962; 1984) also suggested that younger, “namurian b” macrofloras (i.e. belonging to the lyginopteris larischii zone) occurred in the zonguldak area based on evidence in jongmans (1955). from the species mentioned by wagner (in stockmans, 1962) as suggesting a “namurian b” age, it is likely that he was referring to the macroflora from north of the kokaksu valley listed by jongmans (1955, p. 58). this macroflora is very similar to those found in the overlying koslu formation except for the presence of rare sphenophytes comparable with asterophyllites unguis jongmans & gothan and asterophyllites heimansii jongmans & gothan, which are only known from namurian strata (josten, 1983 and references cited therein). however, the robustness of table 2: macrofloras from the alacaağzı formation (gökgöl “member”) in the vicinity of zonguldak and the small outcrops to the west. 1 2 3 4 5 6 7 8 sublepidodendron robertii (nathorst) chaloner x x x x x x x eleutherophyllum mirabile (sternberg) stur x x x sphenophyllum tenerrimum ettingshausen x x x x x pecopteris aspera brongniart ? x ? x alloiopteris quercifolia (göppert) potonié x x sphenopteris elegans brongniart x x x x x x sphenopteris dissecta brongniart ? ? ? ? ? x lyginopteris distans (sternberg) cleal, comb. nov. x x x x x lyginopteris fragilis (brongniart) patteisky x x lyginopteris dicksonioides (göppert) novik x cardiopteridium nanum (eichwald) walton x x x x x adiantites oblongifolius göppert ? ? x x figure 2: stratigraphic ranges of the key macrofloral taxa found in the alacaağzı formation, plotted against the wagner (1984) / cleal (1991) biozonal scheme. ranges mainly as given by wagner (1984). localities: 1 near kirat and tchatal-déré, zonguldak (zeiller, 1899) 2 – kokaksu valley, zonguldak (jongmans, 1955) 3 – ali-mollah seam, kiliç valley, zonguldak (zeiller, 1899; jongmans, 1955) 4 – kilimli tunnel, zonguldak (jongmans, 1955) 5 – gökgöl section, üzülmez deresi, zonguldak (kerey et al., 1986) 6 – kireçlik mines (various coals) (zeiller, 1899; jongmans, 1955) 7 – alacaağzı (jongmans, 1955) 8 – teflenli (zeiller, 1899) cleal and van waveren: a reappraisal of the carboniferous macrofloras of the zonguldak – amasra coal basin, north-western turkey geologia croatica 287 figure 3: stratigraphic distribution of the macrofloral species of the kozlu formation plotted against the lithostratigraphic sequence given by nakoman (1977) (see also kerey, 1985 and kerey et al., 1986). black dots on the range bars designate recorded occurrences of species. geologia croatica 65/3geologia croatica 288 these species as stratigraphical indices for the middle namurian stage remains unproven and the identifications were anyway only given with a “cf.” at the moment it seems more likely that these kokaksu valley macrofloras originated from the koslu formation. kerey et al. (1986) mentioned lycopsid remains from the asma “member” at the top of the formation (e.g. lepidodendron rimosum sternberg) but these are biostratigraphically uninformative. 4.2. kozlu formation this is the main productive interval of the basin for coal and there have been many workings especially in the vicinity of zonguldak. zeiller (1899), jongmans (1955), egemen (1959) and kerey et al. (1986) have provided stratigraphical records of the kozlu formation macrofloras from the zonguldak mines, from which it has been possible to establish a detailed biostratigraphical model (fig. 3). a total of 76 species have been reported from the formation. excluding the stratigraphically highest and lowest two macrofloras (to help remove the edge effect inherent when using through-range data – see foote, 2000 and cleal, 2007 for further discussion on edge effect in such analyses) estimated landscape-scale species diversities (i.e. species diversities within the area of the coalfield) vary from 33 to 56 species (mean 43.2, s. d. 5.0) and local-scale diversities (i.e. species diversities observable at a particular locality) from 3 to 37 species (mean 11.2, s. d. 7.9). this is essentially similar to the diversities recorded by cleal (2007) in the langsettian substage in south wales (landscape diversities mean 38.5, s. d. 5.6; local-scale diversities 13.8, s. d. 5.6). very similar local-scale diversities were also reported by wing & dimichele (1995) from various pennsylvanian macrofloras from north america. although there seems to be some variation in the biostratigraphical distribution of the species through the succession, this is mainly due to 24 singleton species. of the 52 species that occur at more than one stratigraphical level, 39 (75 % of the non-singleton species) range through virtually the entire formation, from the kürtşerif, hacıpetro or çay coal seams near the base to the büyük or stratigraphically higher seams at the top. nearly all of the species that have not been recorded to range through the entire formation are lycopsids and herbaceous, sphenopteroid ferns, which are all rare and therefore subject to potential taphonomy-induced sampling problems. there appears, therefore, to be little significant change in the macrofloras through the formation. when plotted against the biozonal scheme of wagner (1984), the kozlu formation macrofloras correspond to the lyginopteris hoeninghausii zone (fig. 4). cleal (1991) and cleal & thomas (1994) argued that the zone could be divided into a lower, neuralethopteris jongmansii subzone and an upper, laveineopteris loshii subzone, based on the appearance of several taxa, notably laveineopteris loshii (brongniart) cleal et al., (date) laveineopteris tenuifolia (sternberg) cleal et al. (1990) neuropteris heterophylla brongniart and lobatopteris miltonii (artis) wagner. this change can be recognised in britain (cleal, 2005, 2007), northern france (laveine, 1987) and northern germany (josten, 1991), where it occurs about onethird of the way up the langsettian stage. since none of these species have been convincingly documented from the kozlu formation, it seems reasonable to conclude that this interval belongs to the n. jongmansii subzone and is thus early langsettian in age. egemen (1959) reported l. miltonii from kozlu formation macrofloras from çatalldere and virancıkdere, but he stated that the specimens were poorly preserved and none were illustrated. jongmans (1955) also mentioned l. miltonii from the leonodas and sulu seams, but with no comment or justification for the identifications. significantly, zeiller (1899) stated that this species was absent from the kozlu formation. a langsettian age for the kozlu formation is in general accord with the views of jongmans (1955) and kerey et al. (1986). these latter authors suggested that the lower part of the formation might range down into the yeadonian (“namurian c”) substage but without giving evidence in support of this idea. the fact that lyginopteris hoeninghausii and mariopteris dernoncourtii range down into the lowest part of the koslu formation (fig. 4) strongly suggests that the formation does not in fact extend below the base of the figure 4: stratigraphic ranges of the key macrofloral taxa found in the kozlu formation (based mainly on records in jongmans, 1955) plotted against the wagner (1984) / cleal (1991) biozone scheme. ranges mainly as given by wagner (1984), cleal & thomas (1994) and cleal (2005, 2007). cleal and van waveren: a reappraisal of the carboniferous macrofloras of the zonguldak – amasra coal basin, north-western turkey geologia croatica 289 table 3: macrofloras from the karadon formation. 1 2 3 4 5 6 7 8 9 10 lepidodendron aculeatum sternberg x lepidodendron obovatum sternberg auct. x x x bothrodendron minutifolium boulay x sigillaria ovata sauveur x annularia radiata (brongniart) sternberg x x x x x x x annularia rallii (zeiller) x x x annularia spinulosa sternberg x x x x annularia sphenophylloides (zenker) gutbier x x x x asterophyllites charaeformis (sternberg) unger ? x x asterophyllites equisetiformis brongniart x x x x sphenophyllum emarginatum (brongniart) x x x x x sphenophyllum cuneifolium (sternberg) zeiller x x x x x x x x sphenophyllum majus (bronn) bronn x ? ? alloiopteris sternbergii (ettingshausen) potonié x x alloiopteris coralloides gutbier ? x x oligocarpia brongniartii göppert x renaultia chaerophylloides (brongniart) zeiller x x renaultia crepinii (stur) gothan x x renaultia footneri (marratt) brousmiche x x sphenopteris limai zeiller x x x x pecopteris plumosa (artis) brongniart x lobatopteris miltonii (artis) wagner x x eusphenopteris neuropteroides (boulay) novik x ? eusphenopteris nummularia (gutbier) novik x x x ? eusphenopteris striata (gothan) novik ? ? mariopteris dernoncourtii zeiller x x mariopteris nervosa (brongniart) zeiller x x x x x x mariopteris sauveurii (brongniart) zeiller x mariopteris soubeiranii zeiller x palmatopteris furcata (brongniart) potonié x ? ? ? ? alethopteris lonchitica sternberg x x x x x x alethopteris davreuxii (brongniart) zeiller x lonchopteridium karvinense (purkyňova) kerey et al. x reticulopteris muensteri (eichwald) gothan x x x x x x macroneuropteris scheuchzeri (hoffmann) cleal et al. x x x x x x x laveineopteris rarinervis (bunbury) cleal et al. x x x x x laveineopteris tenuifolia (sternberg) cleal et al. ? ? ? ? x paripteris spp. x x x x linopteris neuropteroides (gutbier) zeiller x x x x x x x x linopteris obliqua (bunbury) zeiller x x x x x x x cordaites principalis (germar) geinitz x x ? localities: 1 – taşkesen (jongmans, 1955) 2 – çatalağzı, gelik valley (zeiller, 1899; jongmans, 1955) 3 – along road to çaycuma (jongmans (1955) 4 – behind primary school garden, temmuz mevkii, zonguldak (kerey et al., 1986) 5 – east of söğütözü (jongmans, 1955) 6 – east of dereustudere, near söğütözü (jongmans, 1955) 7 – kilçharman, near söğütözü (jongmans, 1955) 8 – north of karatepe, , near söğütözü (jongmans, 1955) 9 – between başköy and ömerköy, near söğütözü (jongmans, 1955) 10 – özkem köy, near söğütözü (jongmans, 1955) geologia croatica 65/3geologia croatica 290 langsettian l. hoeninghausii zone (in particular, compare with the range of l. hoeninghausii given in patteisky, 1957). plant fossils in what was probably the kozlu formation were also reported by jongmans (1955) from several localities in the azdavay and amasra coalfields. these macrofloras are all essentially the same as those found in the zonguldak coalfield, including lyginopteris baeumleri, l. hoeninghausii, karinopteris acuta and paripteris gigantea, and lacking laveineopteris spp., neuropteris heterophylla and lobatopteris miltonii. despite the reported absence of neuralethopterids, these macrofloras clearly belong to the langsettian l. hoeninghausii zone and probably the lower subzone. 4.3. karadon formation although the karadon formation occurs across the zonguldak – amasra coal basin, there has not been the same level of systematic collecting of plant fossils compared with the kozlu formation (as discussed above). they are best known from the gelik valley near zonguldak; zeiller (1899) and jongmans (1955) mention a plant bed that outcrops at several localities including taşkesen and çatalağzı that has yielded a diverse macroflora. diverse karadon macrofloras have also been found in the vicinity of the villages of azdavay and söğütözü. table 3 summarises the most diverse macrofloras that have been reported to date from this formation. we do not know the relative stratigraphical positions of the various plant-bearing localities within the karadon formation and so it is impossible to develop the same type of biostratigraphical model as we have for the kozlu formation (as shown in fig. 3). however, there is no obvious difference between any of the assemblages in the karadon formation except for how many species each contains; they may, therefore, all be treated together. if the ranges of the most widespread and abundant of the karadon formation species are plotted against the zones of the wagner (1984) / cleal (1991) scheme (fig. 5) it indicates that they belong to the l. rarinervis subzone. similar macrofloras are widespread in variscan euramerica, having been reported from the makedonka formation in the dobrudzha coal basin, bulgaria (cleal et al., 2004), the lembeck formation in northern germany (josten, 1991), the lower pennant formation in south wales (cleal, 2007) and the south bar formation in the canadian maritimes (bell, 1938); for a further discussion on the distribution of this subzone see cleal et al., 2010). in western europe, the zone tends to range from about the level of the cambriense marine band up to the base of the asturian substage, and so is regarded as an index for the upper bolsovian substage. there is no evidence of lonchopteris rugosa or lower paripteris linguaefolia zone floras in the karadon formation. to the south of zonguldak, at exposures along the road to çaycuma and at temmuz, jongmans (1955) and kerey et al. (1986) reported similar macrofloras, but which lack l. rarinervis and include eusphenopteris obtusiloba (brongniart) novik, and which they interpreted as duckmantian in age. in part justification for this opinion, kerey et al. (1986, pl. 10, fig. 1) figured a specimen from here as e. obtusiloba. this interpretation depends on the accepted stratigraphical range of the latter species, which elsewhere does not normally range above the early duckmantian lonchopteris rugosa zone (van amerom, 1975). the specimen figured by kerey et al. (1986) does not show their surface features very clearly, but the pinnules are more deeply incised than is normal for e. obtusiloba and resemble more closely eusphenopteris striata (gothan) novik. this would be more compatible with its co-occurrence with macroneuropteris scheuchzeri, which does not normally range below the late duckmantian neuropteris semireticulata subzone. it is likely, therefore, that these macrofloras are at the oldest, late duckmantian and may in fact be as young as late bolsovian. jongmans (1955) reported another small macroflora from the karadon formation at taarlağzi, east of amasra, which includes sphenophyllum cuneifolium, eusphenopteris cf. neuropteroides (boulay) novik, linopteris neuropteroides and cordaites palmaeformis göppert. jongmans suggested a duckmantian age, but none of these species is diagnostic of the lonchopteris rugosa zone and the quoted assemblage is equally compatible with the paripteris linguaefolia zone. figure 5: stratigraphical ranges of the key macrofloral taxa found in the karadon formation, plotted against the wagner (1984) / cleal (1991) biozone scheme. ranges mainly as given by wagner (1984), cleal & thomas (1994) and cleal (2005, 2007). cleal and van waveren: a reappraisal of the carboniferous macrofloras of the zonguldak – amasra coal basin, north-western turkey geologia croatica 291 table 4: macrofloras from the kızıllı formation. 1 2 3 4 5 6 7 8 9 10 bothrodendron minutifolium boulay x lepidodendron aculeatum sternberg x lepidodendron obovatum sternberg auct. x x x lepidodendron ophiurus brongniart x sigillaria rugosa brongniart x sigillaria tessellata brongniart x x asolanus camptotaenia wood x annularia radiata brongniart x ? x x annularia sphenophylloides (zenker) gutbier x x x x x x x x x annularia spinulosa sternberg ? x ? x x x x x asterophyllites equisetiformis brongniart x x x x x sphenophyllum emarginatum brongniart x x x x x x x x x x sphenophyllum majus (bronn) bronn x x x ? x sphenophyllum oblongifolium (germar & kaulfuss) x x x x urnatopteris tenella (brongniart) kidston x sphenopteris limai zeiller ? sphenopteris vuellersii stur x hymenophyllites quadridactylites (gutbier) kidston x renaultia rotundifolia (andrä) zeiller x x x renaultia footneri (marratt) brousmiche x ? zeilleria delicatula (sternberg) kidston x pecopteris plumosa (artis) brongniart x x x x x x lobatopteris vestita auct. x x x x x x x x acitheca polymorpha (brongniart) schimper x x ptychocarpus unitus (brongniart) zeiller x x x x x x x cyathocarpus sp. x x x x x x x eusphenopteris neuropteroides (boulay) novik ? x ? ? x mariopteris nervosa (brongniart) zeiller x x x x karinopteris daviesii (kidston) boersma ? palmatopteris alata (brongniart) potonié ? ? sphenopteris coemansii stur x dicksonites plukenetii (sternberg) sterzel x x x x x x alethopteris lonchitica sternberg x x ? x x x alethopteris ambigua lesquereux x x x x alethopteris pseudograndinioides zodrow & cleal x x ? alethopteris pontica zeiller x lonchopteris rugosa brongniart x ? callipteridium jongmansii (bertrand) wagner x ? x x ? ? ? callipteridium armasii (zeiller) wagner x ? x x x x ? ? neuropteris ovata hoffmann x x x x x x x x x x odontopteris reichiana gutbier x ? ? ? ? odontopteris cantabrica wagner ? reticulopteris muensteri (eichwald) gothan x x x x x x macroneuropteris scheuchzeri (hoffmann) cleal et al. x x x x x x x x x x laveinopteris rarinervis (bunbury) cleal et al. x x x x x linopteris obliqua (bunbury) zeiller x x x x x x x x x linopteris neuropteroides (gutbier) zeiller x x x x x cordaites spp. x x x x x localities: 1 tarlaağzi, amasra (zeiller 1899; charles, 1931; jongmans, 1955) 2 – grancy, pelitova basin (jongmans, 1955) 3 – azdavavy (jongmans, 1955) 4 – azdavavy, “rayon c” (jongmans, 1955) 5 – kirmaci (jongmans, 1955) 6 – söğütözü (jongmans, 1955) 7 – south of rive de fleuve, north of kızıllı (jongmans, 1955) 8 – red beds near kızıllı (jongmans, 1955) 9 – between cebeci köy and başköy (jongmans (1955) 10 – south of kayabasi, near söğütözü (jongmans, 1955) geologia croatica 65/3geologia croatica 292 jongmans (1955) also reported “karadon” macrofloras from localities near koslu, which were reported to include neuropteris ovata, callipteridium armasii and cyathocarpus sp. jongmans (1955) suggested an asturian age for the macroflora and, if the latter two taxa can be confirmed, it would be to late asturian in age. this is stratigraphically much younger than the other karadon formation macrofloras, and is more comparable in age to the overlying kızıllı formation (see below). 4.4. kızıllı formation the macrofloras of the kızıllı formation are best documented for the pelitova, azdavavy and söğütözü areas in the east of the coal basin, and from where numerous diverse assemblages have been documented (table 4). there has been a general consensus that these strata are asturian (“westphalian d”) in age (jongmans, 1939, 1955; wagner in stockmans, 1962; kerey et al., 1986) partly through the regular appearance of neuropteris ovata. however, other species that also regularly appear include dicksonites plukenetii, callipteridium spp., alethopteris ambigua, alethopteris pseudograndinioides, lobatopteris vestita, acitheca polymorpha, ptychocarpus unitus and cyathocarpus spp. these strongly point to the d. plukenetii subzone in the wagner (1984) / cleal (1991) scheme (fig. 6). similar macrofloras are known from the gurkovo formation in the dobrudzha coalfield, bulgaria (cleal et al., 2004), the libiąż member in upper silesia, poland (migier & kotasowa in zdanowski & żakowa, 1995), the upper heiligenwald formation in saarland (cleal, 1984), in many coalfields in southern britain (cleal, 1997), the southern cantabrian mountains, spain (wagner et al., 1983; wagner & alvarez-vázquez, 1991) and the upper sydney mines formation in the canadian maritimes (zodrow, 1986). since the overlying odontopteris cantabrica zone is taken as an index for the cantabrian substage, the d. plukenetii subzone is an index for the upper asturian substage. at several localities there are also records of odontopteris spp. and sphenophyllum oblongifolium, which suggest possibly the early stephanian odontopteris cantabrica zone; examples of these species were figured by zeiller (1899, pl. 4, figs 3–6; pl. 6, figs 4–5) which would seem to confirm these identifications. however, without some understanding of the species distributions through the formation, it is impossible to be sure if it is partly late asturian and partly early cantabrian in age, or if the entire interval is cantabrian; both views would be compatible with the available biostratigraphical evidence. 5. discussion plant biostratigraphy indicates that the zonguldak – amasra coal basin has terrestrial deposits ranging in age from arnsbergian (latest mississippian) to late asturian or possibly cantabrian (late middle pennsylvanian). there has been a widespread assumption that the succession is continuous; for instance, kerey et al. (1986, p. 211) stated that “there is little discernable evidence for physical breaks in the overall succession…” however, this is not borne out by the plant biostratigraphy, as there is no evidence of any macroflora in the zonguldak – amasra coal basin of middle or late namurian, late langsettian, duckmantian or early asturian age. the only stratigraphically informative macrofloras from the alacaağzı formation (from the gökgöl member) indicate an arnsbergian age. a marine fauna from the overlying tarlaağzı member also indicates an early namurian age (pattison in kerey et al., 1986). this apparent absence of middle and late namurian macrofloras or faunas is difficult to reconcile with the suggestion by kerey et al. (1986) that there is a gradational contact between the alacaağzı and kozlu formations. ralli (1895) and zeiller (1996) recognised the sharp discontinuity between the macrofloras of the kozlu and karadon formations, suggesting that it was part of a regional unconformity. significantly, kerey (1982) also regarded the boundary to be an abrupt lithological break which he later (kerey et al., 1986, p. 206) stated was at “…the base of a succession of thick conglomeratic layers just above the agop coal seam.” kerey (1982) interpreted this as a figure 6: stratigraphic ranges of the key macrofloral taxa found in the kızıllı formation, plotted against the wagner (1984) / cleal (1991) biozone scheme. ranges mainly as given by cleal (1978, 1984, 1997, 2007), wagner et al. (1983), wagner (1984), zodrow & cleal (1985), wagner & alvarez-vázquez (1991) and cleal & thomas (1994). cleal and van waveren: a reappraisal of the carboniferous macrofloras of the zonguldak – amasra coal basin, north-western turkey geologia croatica 293 change from a predominantly meandering fluvio-lacustrine facies to a braided-stream and alluvial fan facies, but may also indicate a break in the sequence. arni (1939) and egemen (1959), in contrast, argued that there was a floristic transition between the kozlu and karadon formations, but this is not borne out by the available evidence: all of the diverse kozlu formation macrofloras unequivocally indicate the langsettian lyginopteris hoeninghausii zone, and probably the lower part of that zone (notably with lyginopteris and neuralethopteris) and all of those from the karadon formation belong to the upper bolsovian paripteris linguaefolia zone, (notably with sphenophyllum emarginatum, mariopteris nervosa, macroneuropteris scheuchzeri, laveineopteris rarinervis). similarly, the suggestion by kerey et al. (1986) that the boundary between the karadon and kızıllı formations is transitional is at variance with the macrofloral evidence, which indicates an absence of middle and late asturian strata. here again, kerey (1982) and kerey et al. (1986) stated that in the pelitova and azdavavy areas the base of the kızıllı formation is marked by beds of pebbly sandstone, this time overlying a coal (the tavan seam), which tends to suggest a break in the sequence. these age estimates were based on the macrofloral biostratigraphy developed by wagner (1984), cleal (1991) and cleal & thomas (1994), mainly in western europe and north america. it is of course always possible that these biozones cannot be applied as far east as the zonguldak – amasra coal basin; it is notable that fissunenko & laveine (1984) reported discrepancies in the stratigraphical ranges of certain plant fossil-species between western europe and the ukraine. in contrast, however, a study of the macrofloral biostratigraphy of the dobrudzha coalfield in northeastern bulgaria showed that this biostratigraphy could be broadly applied when local factors (e.g. marine influence) were taken into account (cleal et al., 2004). okay et al. (1994, 2006) and pharoah (1999) suggested that prior to the late cretaceous opening of the black sea, the istanbul block and moesian platform were located adjacent to each other. this would provide the palaeogeographical context to support the view of tenchov (1989) that the zonguldak – amasra coal basin is part of a belt of coal swamp deposits that extended westwards from the zonguldak – amasra coal basin to the dobrudzha coalfield in bulgaria and upper silesia on the czech – polish border. macrofloral biostratigraphy allows the succession in the zonguldak – amasra coal basin to be compared with these other areas (fig. 7). this suggests individual units can be broadly correlated: the alacaağzı formation with the rakovski formation, the kozlu formation with the lower parts of the załięż beds and the mogilishte formation, the karadon formation with the upper part of the makedonka formation, and the kızıllı formation with the libiąz beds and the gurkovo formation. these units are not only similar in age – there are also broad similarities in the facies present (tenchov, 2005, 2007; kędzior et al., 2007). however, it is also clear that there is a progressive eastwards widening of the stratigraphical gaps in the successions. such disruption to patterns of sedimentation was probably the result of tectonic instability resulting from the suturing of the terrane to the south and figure 7: correlation of the carboniferous successions of the zonguldak – amasra coal basin, the dobrudzha coal basin and the upper silesia coal basin, based on macrofloral biostratigraphy. based on data given in tenchov et al. (in nikolov, 1988), kotasowa & migier (in zdan owski & żakowa, 1995), cleal et al. (2004, 2010, 2011), tenchov (2004, 2005, 2007) and the present paper. geologia croatica 65/3geologia croatica 294 west of the pontides (the sakary – standja terrane – okay et al., 2006) with the moesian – pontides terrane. it has been suggested that the sakary – standja terrane equates to amorica in western europe, and the moesian – pontides terrane to avalonia (stampfli et al., 2002), and so this tectonism observable in northern turkey is in effect an eastwards extension of the variscan orogeny. variscan tectonic activity would, therefore, appear to have started earlier and be more continuous in the area of the moesian – pontides terrane than in more western parts of variscan euramerica. how much this was affecting sediment supply from the hinterland area and how much drainage patterns within the basin is still unclear. it would be informative to have the type of palynology-based vegetation analysis of the zonguldak – amasra coal basin as has been done in dobrudzha (dimitrova & cleal, 2007) to determine the details of the tempo and pattern of vegetation change that took place here during westphalian times. however, the evidence from the zonguldak – amasra coal basin would seem to support the view of cleal et al. (2010, 2011) that the disruption to the coal swamp biome during westphalian times first started in these easternmost parts of variscan euramerica. although only a preliminary analysis of the published data, this paper provides new insights into the wider geological and palaeontological context of the zonguldak – amasra coal basin macrofloras. a detailed taxonomic review is now clearly needed, especially to improve our under standing of the palaeoecological and floristic setting of this area. the w.j. jongmans collection now at naturalis (leiden, the netherlands) probably offers the best starting point for such an analysis. acknowledgement this paper is a contribution to igcp 575: pennsylvanian terrestrial habitats and biotas of southeastern euramerica. it arose out of the first project meeting held at zonguldak in 2010, which was organised by prof. vedat didari (karaelmas university, zonguldak) and his colleagues. the authors are grateful to prof. vedat didari, and to dr. hülya i̇naner (dokuz eylül university, i̇zmir), for helpful discussions on the background to the zonguldak – amasra coal basin; and to prof. barry thomas (aberystwyth university) for advice on lycopsid taxonomy. a preliminary version of this paper was presented at the 2011 meeting of igcp 575 held at the university of zagreb (croatia), and the authors thank the organisers of that meeting, notably dr. jasenka sremac. appendix taxonomic remarks on selected species these remarks are not intended to be exhaustive, but are merely to clarify the usage of some of the species names in this paper, and why they differ from those used in the original publications. lepidodendron obovatum sternberg auct. this species has been the subject of much confusion. thomas (1970) re-examined the type specimen and came to the conclusion that it was a synonym of l. aculeatum sternberg. however, many authors have referred specimens to l. obovatum that are really l. mannabachense presl. the distinction between l. aculeatum and l. mannabachense is based on surface features of their cushion and on their epidermal details (thomas, 1970), so we are uncertain to which of these two species the l. obovatum determinations should be referred. sublepidodendron robertii (nathorst) chaloner in boureau et al., 1967 (= lepidodendron robertii nathorst, 1914). chaloner (in boureau et al., 1967) transferred l. robertii to sublepidodendron presumably as it was thought to be eligulate, although this negative feature has yet to be clearly confirmed. cardiopteridium nanum (eichwald) walton, 1941 (= cyclopteris nana eichwald, 1860; ≡ cardiopteridium spetsbergense nathorst, 1914; ≡ cardiopteridium waldenburgense zimmermann, 1932). zeiller (1899) referred to this species as cardiopteris polymorpha (göppert) schimper, but jongmans (1955) correctly attributed it to cardiopteridium. jongmans used the species name c. waldenburgense but walton (1941) had earlier shown that this species merely represents slightly larger forms of c. nanum, the latter name taking priority. lyginopteris distans (sternberg) cleal & van waveren, comb. nov. (= sphenopteris distans sternberg, 1825; = sphenopteris bermudensiformis schlotheim ex zeiller, 1899; = lyginopteris bermudenseformis (schlotheim ex zeiller) patteisky, 1929). this species was referred to as s. bermudensiformis by zeiller (1899) and jongmans (1955), who attributed the name to schlotheim (1820). however, as schlotheim’s (1820) pre-dates the starting-point for the publication of plant fossil species names (icbn, art. 13.1 – mcneill et al., 2006), the earliest valid publication of the name must be taken to be zeiller (1899). as pointed out by kvaček & straková (1977), this is, therefore, predated by the nomenclatural synonym s. distans. following patteisky (1957), there can be little doubt that this species belongs to the fossil-genus lyginopteris and so a new combination is proposed here. lyginopteris fragilis (schlotheim ex brongniart) patteisky, 1955 (= sphenopteris fragilis schlotheim ex brongniart, 1828; ≡ cheilanthites divaricatus göppert, 1836; ≡ sphenopteris divaricata (göppert) gutbier in cotta et al., 1843). jongmans (1955) recorded this species as sphenopteris divaricata but according to patteisky (1955) this is a later taxonomic synonym of lyginopteris fragilis. the latter name is usually attributed to schlotheim (1820) but is regarded as published before the starting-point for the publication (icbn, art. 13.1). sphenopteris elegans brongniart, 1822 (≡ sphenopteris adiantoides schlotheim ex lindley & hutton, 1834). jongmans (1955) referred to this species as cleal and van waveren: a reappraisal of the carboniferous macrofloras of the zonguldak – amasra coal basin, north-western turkey geologia croatica 295 s. adiantoides, attributing the name to schlotheim (1820). however, schlotheim’s (1820) book pre-dates the starting-point for the publication of names for plant fossil-species (icbn, art. 13.1 – mcneill et al., 2006). the earliest validly published use of this species name was by lindley & hutton (1834), but this was predated by its taxonomic synonym s. elegans, and so the latter must take priority. references arni, p. (1939): neue geologische geschichtspunkte für den bergbau im westlichen steinkohlenbecken nordanatoliens.– maden tetkik ve arama enstitüsü yayinlarindan, seri b: irdeller, 4/17, 55–63. bell, w.a. (1938): fossil flora of sydney coalfield, nova scotia.– canada department of mines and resources, geological survey memoir, 215, 1–334. boureau, e., jovet-ast, s., høeg, o.a. & chaloner, w.g. (1967): traité de paléobotanique 2. bryophyta, psilophyta, lycophyta.– mason et cie, paris, 845 p. bouroz, a., knight, j.a., wagner, r.h. & winkler-prins, c.f. (1972): sur la limite westphalien–stéphanien et sur les subdivisions du stéphanien inférieur sensu lato. compte rendu 7e congrès de stratigraphie et de géologie du carbonifère (krefeld, 1971), 1, 241–261. brongniart, a. (1822): sur la classification et la distribution des végétaux fossiles en général, et sur ceux des terrains de sediment supérieur en particulier.– mémoires du museum d’histoire naturelle, paris, 8, 203–240, 297–348. brongniart, a. (1828): prodrome d’une histoire des végétaux fossiles.– f.g. levrault, paris & strasbourg, 223 p. burek, c.v. & cleal, c.j. (2005): the life and work of emily dix (1904–1972).– in: bowden, a.j., burek, c.v. & wilding, r. (eds): history of palaeobotany: selected essays. geological society, london, special publication, 241, 181–196. charles, f. (1931): note sur le houiller d’amasra (asie mineure).– bulletin del la société géologique belgique, 54, 151–178. cleal, c.j. (1978): floral biostratigraphy of the upper silesian pennant measures of south wales.– geological journal, 13, 165–194. cleal, c.j. (1984): the westphalian d floral biostratigraphy of saarland (fed. rep. germany) and a comparison with that of south wales.– geological journal, 19, 327–351. cleal, c.j (1991): carboniferous and permian biostratigraphy.– in: cleal, c.j. (ed.): plant fossils in geological investigation: the palaeozoic. ellis horwood, chichester, 182–215. cleal, c.j. (1997): the palaeobotany of the upper westphalian and stephanian of southern britain and its geological significance.– review of palaeobotany and palynology, 95, 227–253. cleal, c.j. (2005): the westphalian macrofloral record from the cratonic central pennines basin, uk.– zeitschrift der deutschen gesellschaft für geowissenschaften, 156, 387–410. cleal, c.j. (2007): the westphalian-stephanian macrofloral record from the south wales coalfield.– geological magazine, 144, 465–486. cleal, c.j., opluštil, s., thomas, b.a. & tenchov, y. (2010): late moscovian terrestrial biotas and palaeoenvironments of variscan euramerica.– netherlands journal of geosciences, 88, 181–278. cleal, c.j., opluštil, s., thomas, b.a. & tenchov, y. (2011): pennsylvanian vegetation and climate in tropical variscan euramerica.– episodes, 34, 3–12. cleal, c.j., tenchov, y. & zodrow, e.l. (2004): review of the late westphalian early stephanian macrofloras of the dobrudzha coalfield, bulgaria.– geologica balcanica, 34, 11–20. cleal, c.j. & thomas, b.a. (1994): plant fossils of the british coal measures.– palaeontological association, london (field guide to fossils), 222 p. cleal, c.j. & thomas, b.a.(2010a): botanical nomenclature and plant fossils.– taxon, 59, 261– 268. cleal, c.j. & thomas, b.a.(2010b): proposals to modify the provisions in the code for naming plant fossils.– taxon, 59, 312– 313. cotta, b., geinitz, h.b., gutbier, a., naumann, c., reichenbach. l. & schiffner, m.a. (1843): gäa von sachsen. arnold, leipzig, 225 p. davydov, v.i., crowley, j.l., schmitz, m.d. & poletaev, v.i. (2010): high-precision u-pb zircon age calibration of the global carboniferous time scale and milankovitch band cyclicity in the donets basin, eastern ukraine.– geochemistry, geophysics, geosystems, 11/1, doi:10.1029/2009gc002736 (22 p). dimitrova, t.kh. & cleal, c.j. (2007): palynological evidence for late westphalian – early stephanian vegetation change in the dobrudzha coalfield, ne bulgaria.– geological magazine, 144, 513–524. dix, e. (1934): the sequence of floras in the upper carboniferous, with special reference to south wales.– transactions of the royal society of edinburgh, 57, 789–838. dix, e. (1937): the succession of fossil plants in the south wales coalfield with special reference to the existence of the stephanian.– deuxième congrès pour l’avancement des études de stratigraphie du carbonifère, heerlen 1935, compute rendus, 1, 159–184. egemen, m.r. (1958): on the significance of some forms of neuropteris gigantea sternberg from the carboniferous of anatolia (turkey).– journal of the palaeontological society of india, 3, 179–184. egemen, m.r. (1959): on the significance of the flora found in the i̇hsaniye beds at kozlu. zonguldak.– révue de la faculté des sciences de l’université d’istanbul, série b: sciences naturelles, 24, 1–24. eichwald, e. (1860): lethaea rossica ou paléontologie de la russie, 1.– schweizerbart, stuttgart, 1657 p. fissunenko, o.p. & laveine, j.-p. (1984): comparaison entre la distribution des principales espèces-guides végétales du carbonifère moyen dans le bassin du donetz (urss) et les bassins du nord-pas-de-calais et de lorraine (france).– compte rendu 9e congrès de stratigraphie et de géologie du carbonifère (washington and urbana, 1979), 1, 95–100. foote, m. (2000): origination and extinction components of taxonomic diversity.– paleobiology, 26, 74–102. göppert, h. (1836): systema filicum fossilium.– e. weber, breslau and bonn, 486 p. grancy, w.s. (1939): ueberblick über die bisherigen aufschlussarbeiten und ergebnisse im östlichen anatolisches steinkohlenbecken.– maden tetkik ve arama enstitüsü yayinlarindan, seri b: irdeller, 4/17, 75–88. güney, m. (1967): underground mining operations in zonguldak coal mines.– bulletin of the mineral research and exploration institute of turkey, 68, 89–124. hartung, w. (1937): das karbon des balkangebietes einschliesslich heraclea (kl. -asien).– compte rendu 2e congrès pour l’avancement des études de stratigraphie carbonifère (heerlen, 1935), 1, 251–261. heckel, p.h. & clayton, g. (2006): the carboniferous system. use of the new official names for the subsystems, series and stages.– geologica acta, 4, 403–407. geologia croatica 65/3geologia croatica 296 i̇naner, h. & nakoman, e. (2004): resources, quality and economic importance of solid fossil fuels in turkey.– geologica belgica, 7, 245–250. jongmans, w.j. (1939): anadolu kömür havzasının şark kısımlarında bulunan karbon formasiyonuna ait nebatî fosiller hakkında etüd.– maden tetkik ve arama enstitüsü yayinlarindan, seri b: irdeller, 2, 1–40. jongmans, w.j. (1955): notes paléobotaniques sur les bassins houillers de l’anatolie.– mededelingen van de geologische stichting, nieuwe serie, 9, 55–89. josten, k.h. (1983): die fossilen floren im namur des ruhrkarbons.– fortschritte in der geologie von rheinland und westfalen, 31, 1–327. josten, k.h. (1991): die steinkohlen-floren nordwestdeutschlands.– fortschritte in der geologie von rheinland und westfalen, 36, 1–434. kalvoda, j. & bábek, o. (2010): the margins of laurussia in central and southeast europe and southwest asia.– gondwana research, 17, 526–545. kędzior, a., gradziński, r., doktor, m. & gmur, d. (2007): sedimentary history of a mississippian to pennsylvanian coal-bearing succession – an example from the upper silesia coal basin, poland.– geological magazine, 144, 487–496. kerey, i.e. (1982): stratigraphical and sedimentological studies of upper carboniferous rocks in northwestern turkey.– unpublished phd thesis, university of keele, 232 p. kerey, i.e. (1985): facies and tectonic setting of the upper carboniferous rocks of northwestern turkey.– in: dixon, j.e. & robertson, a.h.f. (eds.): the geological evolution of the eastern mediterranean. geological society, london, special publication, 17, 123–128. kerey, i.e., kelling, g. & wagner, r.h. (1986): an outline stratigraphy and palaeobotanical records from the middle carboniferous rocks of northwestern turkey.– annales de la société géologique du nord, 105, 203–216. kulaksazov, g. & tenchov, y. (1973): stratigrafiya na dolniya karbon ot dobrudzhanskiya buglishchen basein.– izvestiya geologicheskiya institut, seriya stratigrafiya i lithologiya, 22, 39–53. kullmann, j., wagner, r.h. & winkler prins, c.f. (2007): significance for international correlation of the perapertú formation in northern palencia, cantabrian mountains. tectonic/stratigraphic context and descriptions of mississippian and upper bashkirian goniatites.– revista española de paleontología, 22, 127–145. kvaček, j. & straková, m. (1997): catalogue of fossil plants described in works of kaspar m. sternberg.– national museum, prague, 201 p. laveine, j.-p. (1977): report on the westphalian d.– in: holub, v.m. & wagner, r.h. (eds): symposium on carboniferous stratigraphy. geological survey, prague, 71–83. laveine, j.p. (1987): la flore du bassin houiller du nord de la france. biostratigraphie et méthodologie.– annales de la société géologique du nord, 106, 87–93. laveine, j.p. (1997): synthetic analysis of the neuropterids. their interest for the decipherment of carboniferous palaeogeography.– review of palaeobotany and palynology, 95, 155–189. lindley, j. & hutton, w. (1834): the fossil flora of great britain. volume 2 (part 2).– w. j. ridgeway & sons, london, 57–156. mcneill, j., barrie, f.r., burdet, h.m., demoulin, v., hawks worth, d.l., marhold, j., nicholson, d.h., prado, j., silva, p.c., skog, j.e., wiersema, j.h. & turland, n.j. (2006): international code of botanical nomenclature (vienna code).– a.r.g. gantner verlag, ruggell, liechtenstein, 568 p. mcneill, j. & turland, j. (2011): major changes to the code of nomenclature – melbourne, july 2011.– taxon, 60, 1495–1497. nakoman, e. (1977): études palynologiques des veines d’âge namurien et du westphalien a des secteurs de karadon et d’üzülmez du basin houiller de zonguldak.– maden tetkik ve arama enstitüsü yayinlarindan, seri b: irdeller, 87, 67–96. nathorst, a.g. (1914): zur fossilen flora der polarländer i (4).– p.a. norstedt & söner, stockholm, 110 p. nikolov, z. (ed.) (1988): geologiya na dobrudzhanskiya buglishchne basein.– tekhnika, sofia, 170 p. okay, a.i̇., satir, m. & siebel, w. (2006): pre-alpide palaeozoic and mesozoic orogenic events in the eastern mediterranean region.– in: gee, d.g. & stephenson, r.a. (eds.): european lithosphere dynamics. memoirs of the geological society, london, 32, 389–405. okay, a.i̇., şengör, a.m.c., görür, n. (1994): kinematic history of the opening of the black sea and its effect on the surrounding regions.– geology, 22, 267–270. patteisky, k. (1929): die geologie und fossilführung der mährischschlesischen dachschiefer und grauwackenformation. – naturwissenschaftliche verein in troppau, opava, 354 p. patteisky, k. (1957): die phylogenetische entwicklung der arten von lyginopteris und ihre bedeutung für die stratigraphie.– mitteilungen der westfälischen berggewerkschaftskasse, 12, 59–83. pharaoh, t.c. (1999): palaeozoic terranes and their lithospheric boundaries within the trans-european suture zone (tesz): a review.– tectonophysics, 314, 17–41. purkyňová, e. (1970): die unternamurflora des beckens von horní slezsko (cssr).– paläontologische abhandlungen, abteilung b, 3, 129–268. ralli, g. (1896): le bassin houiller d’héraclée.– annales de la société géologique de belgique, 23, 151–267. ralli, g. (1933): le bassin houiller d’héraclée et la flore du culm et du houiller moyen.– zellitch frères, istanbul, 166 p. schlehan, m. (1852): versuch einer geognostischen beschreibung der gegend zwischen amasry und tyrla-asy and der nord-küste von klein-asien.– zeitschrift der deutschen geologischen gesellschaft, 4, 96–203. schlotheim, e.f. von (1820): die petrefactenkunde auf ihrem jetzigen standpunkte durch die beschreibung seiner sammlung versteinerter und fossiler überreste des thierund pflanzenreichs der vorwelt erläutert.– gotha, 437 p. schmitz, m.d. & davydov, v.i. (2012): quantitative radiometric and biostratigraphic calibration of the pennsylvanian–early permian (cisuralian) time scale and pan-european chronostratigraphic correlation.– gsa bulletin, doi: 10.1130/b30385.1. spratt, t. (1877): remarks on the coal-bearing deposits near erekli (the ancient heraclea pontica, bithynia).– quarterly journal of the geological society, london, 33, 525–533. stampfli, g.m., von raumer, j.f. & borel, g.d. (2002): paleozoic evolution of pre-variscan terranes: from gondwana to the variscan collision.– in: martínez catálan, j.r., hatcher, r.d., arenas, r. & díaz garcía, f. (eds): variscan – appalachian dynamics: the building of the late palaeozoic basement. geological society of america, special papers, 364, 263–280. sternberg, k.m. von (1825): versuch einer geognostisch-botanischen darstellung der flora der vorwelt, 1(4), tentamen.– e. brenck’s wittwe, regensburg, 48 + xlii p. stockmans, f. (1962): paléobotanique et stratigraphy.– compte rendu 4e congrès pour l’avancement des études de stratigraphie et de géologie du carbonifère (heerlen, 1958), 3, 657–682. tenchov, y.g. (1989): possible position of the variscan chains between the balkan and caucasus.– geologica balcanica, 19/3, 3–7. cleal and van waveren: a reappraisal of the carboniferous macrofloras of the zonguldak – amasra coal basin, north-western turkey geologia croatica 297 tenchov, y.g. (2004): rakovski formation (carboniferous, ne bulgaria) – stratigraphy, sedimentary conditions and interpretation.– geologica balcanica, 34, 85–96. tenchov, y.g. (2005): early westphalian sediments of dobrudzha coalfield (ne bulgaria) – an interpretation of their stratigraphy and sedimentation conditions.– zeitschrift der deutschen gesellschaft für geowissenschaften, 156, 467–480. tenchov, y.g. (2007): late westphalian and early stephanian sediments of the dobrudzha coalfield, ne bulgaria.– geological magazine, 144, 497–511. thomas, b.a. (1970): epidermal studies in the interpretation of lepidodendron species.– palaeontology, 13, 145–173, tokay, m. (1962): the geology of the amasra region with special reference to some carboniferous gravitational gliding phenomena.– bulletin of the mineral research and exploration institute of turkey, 58, 1–20. van amerom, h.w.j. (1975): die eusphenopteridischen pteridophyllen aus der sammlung des geologischen bureaus in heerlen, unter besonderer berücksichtigung ihrer stratigraphie bezüglich des südlimburger kohlenreviers.– mededelingen rijks geologische dienst, serie c-iii-1, 7, 1–202. wagner, r.h. (1984): megafloral zones of the carboniferous.– compte rendu 9e congrès international de stratigraphie et de géologie du carbonifère (washington, 1979), 2, 109–134. wagner, r.h. (1994): climatic significance of the major chronostratigraphic units of the upper palaeozoic.– compte rendu 12e congrès international de stratigraphie et de géologie du carbonifère, 1, 83–108. wagner, r.h. (1997): wilhelmus josephus jongmans (1878-1957): the personality and his achievements.– mededelingen nederlands instituut voor toegepaste geowetenschappen. tno, 58, 17–30. wagner, r.h. (1998): consideraciones sobre los pisos de la serie estefaniense.– monografias de la academia de ciencias exactas físicas químicas y naturales de zaragoza, 13, 9–19. wagner, r.h. & alvarez-vázquez, c. (1991): floral characterisation and biozones of the westphalian d stage in nw spain.– neues jahrbuch für geologie und paläontologie, abhandlungen, 183, 171–202. wagner, r.h. & amerom, h.w.j van (1995): wilhelmus josephus jongmans (1878–1957): paleobotanist, carboniferous stratigrapher, and floral biogeographer.– memoirs of the geological society of america, 185, 75–90. wagner, r.h., fernandez-garcia, l. & eagar, r.m.c. (1983): geology and palaeontology of the guardo coalfield (ne león – nw palencia), cantabrian mts.–instituto geologico y minero de españa, madrid, 109 p. walton, j. (1941): on cardiopteridium, a genus of fossil plants of lower carboniferous age, with special reference to scottish specimens.– proceedings of the royal society of edinburgh, section b, 61, 59–66. walton, j., weir, j. & leitch, d. (1938): a summary of scottish carboniferous statigraphy and palaeontology.– compte rendu 2e congrès international de stratigraphie et de géologie du carbonifère (heerlen, 1935), 3, 1343–1356. waters, c.n. (2001): definitions of chronostratigraphic subdivisions: geochronology and event stratigraphy.– in: waters, c.n., somerville, i.d., jones, n.s., cleal, c.j., collinson, j.d., waters, r.a., besly, b.m., dean, m.t., stephenson, m.h., davies, j.r., freshney, e.c., jackson, d.i., mitchell, w.i., powell, j.h., barcalay, w.j., browne, m.a.e., leveridge, b.e., long, s.l. & mclean, d. a revised correlation of carboniferous rocks in the british isles. geological society special report, 26, 3–10. waters, c.n. & condon, d.j. (2012): nature and timing of late mississipppian to mid-pennsylvanian glacio-eustatic sea-level changes of the pennines basin, uk.– journal of the geological society, london, 169, 37–51. wing, s.l. & dimichele, w.a. (1995): conflict between local and global changes in plant diversity through geological time.– palaios, 10, 551–564. yanev, s., göncüoğlu, m.c., gedik, i., lakova, i., boncheva, i., sachanski, v., okuyucu, c., özgül, n., timur, e., maliakov, y. & saydam, g. (2006): stratigraphy, correlations and palaeogeography of palaeozoic terranes of bulgaria and nw turkey; a review of recent data.– in: robertson, a.h.f. & mountrakis, d. (eds): tectonic development of the eastern mediterranean region. geological society, london, special publication, 260, 51–67. zdanowski, a. & żakowa, h. (1995): the carboniferous system in poland.– prace pañstwowego instytutu geologicznego, 148, 1–215. zeiller, r. (1896): sur la flore des depôts houillers d’asie mineure et sur la présence, dans cette flore, du genre phyllotheca.– comptes rendus de l’académie des sciences, paris, 120, 1228–1231. zeiller, r. (1899): étude sur la flore fossile du basin houiller d’héraclée (asie mineure). mémoires de la société géologique de france, paléontologie, 21, 1–91. zimmermann, w. (1932): über cardiopteridium u. c. wäldenburgense n.sp. aus den waldenburger schichten.– arbeiten aus dem institut für paläobotanik und petrographie der brennsteine, 2, 219–232. zodrow, e.l. (1986): succession of paleobotanical events: evidence for mid-westphalian d floral changes, morien group (late pennsylvanian, nova scotia).– review of palaeobotany and palynology, 47, 293–326. zodrow, e.l. & cleal, c.j. (1985): phytoand chronostratigraphical correlations between the late pennsylvanian morien group (sydney, nova scotia) and the silesian pennant measures (south wales).– canadian journal of earth sciences, 22, 1465 –1473. manuscript received february 01, 2012 revised manuscript accepted april 04, 2012 available online october 30, 2012 2019 | 72 / special issue | 145–153 | 7 figs. | 2 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society article history: manuscript received may 13, 2019 revised manuscript accepted august 30, 2019 available online december 20, 2019 keywords: n deposition, nitrogen mineralization, n transformation, forest soil, flux 1. introduction the mineralization level of organic nitrogen is an important indicator of soil nitrogen supplying capacity (burton et al., 2007). it also influences the circulation rate of soil nitrogen and the productivity level of a forest (ouyang et al., 2008). there is a correlation between atmospheric nitrogen deposition, soil nitrogen transformation, and nitrogen leaching (vestgarden et al., 2003; sultana et al., 2004; brenner et al., 2005). atmospheric nitrogen deposition can also influence the minera­ lization and nitrification rate of forest soil nitrogen which can lead to nitrogen loss (aber & magill, 2004; mcnulty et al., 2005) and nitrogen storage change (david et al., 1998). some research shows that an increase in simulated nitrogen deposition promotes the net mineralization flux of forest soil nitrogen (vestgarden et al., 2003; brenner et al., 2005) in the early phase of the experiment, but such promotion weakens gradually over time (magill et al., 1996; magill et al., 2000). alternatively, other research shows that nitrogen deposition increase inhibits (jussy et al., 2004) or does not influence (emmett et al., 1995; gundersen et al., 1998) the net mineralization flux of forest soil nitrogen. in view of this, it is necessary to further the current understanding of the effects of nitrogen deposition increase on the net mineralization flux of forest soil nitrogen. this will help to predict the characteristics of the soil nitrogen transformation fluxes in forest ecosystems of different areas and the response to future atmospheric nitrogen deposition increase. investigation of in situ soil nitrogen mineralization in a picea-abies forest on the tibet plateau: effects of increased nitrogen input wang ge1, han lin2*, tang xinying1 and yang yu2 1 institute of plateau meteorology, china meteorological administration, chengdu 610072, china 2 chengdu university of information technology, chengdu 610225, china doi: 10.4154/gc.2019.27 abstract the main objective of this study was to quantify the dynamics of ammonium (nh4 +) and nitrate (no3 -) in the humus (0-7cm) and the uppermost mineral layer (0-15cm) of a forest soil. the soil was treated annually from 2012 to 2013 with one single dose of nitrogen (0, 15, 30kg n ha-1yr-1 applied as (nh4)2so4, nh4cl, kno3). net n mineralization, including net ammonification and net nitrification was determined in four in situ incubation periods over 2 years in a picea-abies forest stand at the qinghai-tibet plateau, southwest china. measurements were done using soil cores (7cm or 15cm deep) with a resin bag filled with combined anion and cation exchange resins placed at the base to collect the n leaching from the soil. the accumulation rate of n was corrected for both deposition and fertilizer n inputs. in all treatments, both the content and accumulation of the mineral n were dominated by nh4 + which accounts for about 76-89% of the net mineralization. the accumulation rate of n decreased to 64-83% in kno3 treatments. the net n mineralization rate increased with nitrogen input, especially in nh4 +-n treatments (p<0.05). however, this promoting role decreased over time. at the highest (nh4)2so4 additions, the net ammonification and net mineralization rate increased notably in the humus (0-7cm) rather than in the uppermost mineral layer (0-15 cm). previous studies that reported on soil net mineralization from forests under different environmental conditions were compiled and assessed for the effects of atmospheric n deposition and environmental factors, annual precipitation, and annual temperature on annual fluxes of net nitrogen mineralization in forest soils, worldwide. the results show that an increase in atmospheric n deposition significantly enhances the soil net nitrogen mineralization rate. variation in atmospheric n deposition accounts for 48% of the variation in the rate of soil net nitrogen mineralization across the forests. china is the third largest nitrogen deposition concentration area in the world (richter et al., 2005). however, most of the research on atmospheric nitrogen deposition on forest soil nitrogen behaviours is conducted in laboratories (zhou & ouyang et al., 2001; zhou et al., 2003). the dilemma here is that this cannot properly reflect the in­situ soil nitrogen transformation (arnold et al., 2008) unless in-situ studies are conducted. at present, very few in­situ field research activities are underway in china to investigate the effects of atmospheric nitrogen deposition increase on forest soil nitrogen transformation flux. most of the reported research concerns subtropical/tropical forest ecosystems (meng et al., 2001; fang et al., 2004; li & sha 2005; chen & jan, 2007). hence, this cannot be considered enough for a comprehensive assessment of the effects of atmospheric nitrogen deposition on net transformation of forest soil nitrogen in different areas in china. nevertheless, there are many in situ observations reported in the international literature on net transformation fluxes of temperate forest soil nitrogen. to the best of our knowledge, there is a lack of research on comprehensive assessment of the effects of deposition of different forms of nitrogen, different forest types, and different climatic factors on the net mineralization flux of soil nitrogen. to address this issue, a comprehensive in-situ investigation of the effects of simulated atmospheric nitrogen deposition increase on net mineralization flux of forest soil nitrogen in a site located in qinghai-tibet plateau forest was conducted over a peg eo lo gi a c ro at ic a geologia croatica 72 / special issue146 riod of two years. this timely research will help to further our current understanding and the extent of the effects of nitrogen deposition on the net mineralization flux of forest soil nitrogen and the effect of climatic factors on the net mineralization flux of forest soil nitrogen. 2. materials and methods 2.1. the study area the study area is located in the comprehensive observation station of the chinese academy of sciences in nyingchi lulang town of the tibet autonomous region (29°46’n, 94°44’e) of the southeast mountain region. the study area has a flat topography with an elevation of 3200 metres above sea level. the nyingchi area is a typical tropical humid and semi­humid climate affected by the indian ocean and the pacific warm current. it features a short frost-free period (about 170 days throughout the year) and a long frozen period, dry and windy in spring, short and warm summer, cool and foggy autumn, and long and sunny cold winter. the average annual temperature is 12℃. the annual average rainfall is 600-800mm and 92.4% of the rainfall occurs in spring. the vegetation type is coniferous picea-abies forest in the tibetan plateau. the forest type is a mature virgin forest and the dominant tree species are on average more than 100 years old. the main tree species include: abies georgei var. smithii, picea likiangenses var. linzhiensis, pinus yunnanensis and pinus densata. the soil in this area is a cambisol. 2.2. sample collection and analysis self-made rain collectors were used to gather penetration rainwater. the rainwater collector consists of a funnel and a collection bottle. according to seasonal changes in rainfall intensity, 2-3 random samplings were made in each month. in total, 16 collectors were evenly placed around the experimental area to capture the regional heterogeneity in precipitation rate at the site. the sampling period was from may to october during 2012 and 2013. the resin core method proposed by bhogal et al. (1999) was used for the in­situ measurement of the net ammonification, net nitrification, and net mineralization fluxes of soil nitrogen. considering the thickness of soil layer a and fine root system distribution in the forest, the organic-layer soil depth and “fulllayer” soil depth were determined as 0-7cm and 0-15cm, respectively. these were used as benchmarks for other observations in order to understand any correlation between soil nitrogen transformation flux and the net fluxes of the soil’s surface carbon and nitrogen gases, and also the correlation between soil nitrogen transformation flux and the leaching fluxes of the soil’s surface carbon and nitrogen gases. the field experiments began in july 2012. at first, four sampling points adjacent to each other were selected in each treated quadrat, and two repeated treatments were designed for organic layers and full layers in each sampling points. then, the surface vegetation was completely cleared off, some pvc pipes (7.0cm in diameter and 7.0cm in height for organic layers, 7.0 cm in diameter and 15.0cm in height for full layers) were driven by a hammer into the soil. the pipes then were carefully removed and soil of 2 cm thick was removed from bottom of the pipes and the remaining soil was then put into the prepared resin bags. each bag contained 20g of cation­anion exchange resin. finally, the pvc pipes were buried in the original places. prior to the experiment, the amount of soil taken from 0­7 cm layer and 0­15 cm layer outside the experimental plot was considered as the initial baseline values of soil nitrogen mineralization. then, the soil was sampled in september and november 2012 and april, july, and november 2013. after every sampling, new pipes were buried in new places in the experiment plot until the end of the experiment in november 2013. all the samples were sieved and kept frozen for later analysis. plots of 5m´5m were arranged into three blocks and fertilizer-n was added as annual single doses of (nh4)2so4, nh4cl and kno3 from 2012. the doses are 0 (control), 15 (low n) and 30 (high n) kg n ha-1yr-1. 2.3. statistical analysis for the soil samples from two different depths, the net ammonification flux of the soil nitrogen can be calculated as the differe­ nce between the nh4 +-n content in the counterpart soil layers between two adjacent samplings plus the nh4 +-n content absorbed by the resin. the net nitrification flux of the soil nitrogen is the difference between the no3 --n content in the counterpart soil layers between two adjacent samplings plus the no3 --n content absorbed by the resin. the net mineralization flux of the soil nitrogen is the sum of the net ammonification flux and the net nitrification flux (hatch et al., 2000). the monthly forest precipi­ tation nitrogen deposition flux during the field observation period was calculated by multiplying the precipitation volume mean concentration and the precipitation amount. the total dissolved nitrogen (dn) in precipitation was been determined with a toc/tn analysis meter (shimadzu tocvcsh/tn). dissolved organic nitrogen (don) in precipitation was also calculated based on the difference between the total nitrogen content and the content of mineral nitrogen. the content of nh4 +-n and no3 --n in precipitation, resin, and soil samples was determined by the colorimetric method (kim, 1995). the unit of nitrogen deposition flux in different forms in precipitation and of flux of mineral nitrogen in resin is mg n m-2. for all the forest soil nitrogen mineralization fluxes, the ave­ rage values and standard errors were calculated. a one-way anova method in a t-test provided using software spss11.5 was employed to compare the morphological differences among the deposition of nitrogen in its different forms (p<0.05). factor analysis in spss-data reduction was conducted to investigate the differences in net ammonification, net nitrification, and net mine­ ralization fluxes of forest soil nitrogen in different years and under various conditions of nitrogen application. stepwise regression analysis in spss­regression was used to analyze the key factors in soil attributes, average annual temperature, and annual precipitation which influence the net mineralization flux of forest soil nitrogen. with reference to the literature and based on spss factor analysis, the key factors influencing annual net mineralization flux of regional forest soil nitrogen were investigated. for all the results obtained, average values and standard errors were calculated. the annual nitrogen deposition is the sum total of every monthly figure. the unit of nitrogen sediment fluxes of different forms are kg n ha-1. regression analysis and correlation coefficients between different forms of nitrogen concentrations in wet sediment and atmospheric temperature or precipitation was conducted by the one-way anova of spss. 3. results and discussion 3.1. change law of nitrogen wet sediment atmospheric temperature and precipitation in the growing seasons during 2011 and 2013 are shown in figure 1. these two climate factors have significant seasonal variation, the highest in g eologia c roatica ge et al.: investigation of in situ soil nitrogen mineralization in a picea-abies forest on the tibet plateau: effects of increased nitrogen input 147 summer, and the lowest in the spring and autumn. at the same time, there is a big difference in precipitation during each year. figure 2. shows different forms of nitrogen (nh4 +-n, no3 -n, tin (total inorganic nitrogen, tin), tn (total nitrogen, tn)) concentrations in wet sediment flux from may to october in 2012 and 2013. from figure 1. it can be seen that the atmospheric nitrogen deposition has a significant seasonal change. high values of inorganic n concentration were found in summer; while, low values were observed in spring. in 2012, nh4 +-n, no3 --n and the total mineral nitrogen in the atmospheric wet sediment of coniferous picea-abies forest in the tibetan area were 5.06, 2.21, and 8.71 kg n ha-1 yr-1, respectively. while, the amount of these forms of nitrogen were 2.93, 0.44, and 5.58 kg n ha-1 yr-1 in 2013 (table 1), respectively. ammonium nitrogen is the main proportion of the mineral nitrogen sediment which accounts for about 73-87% of the mineral nitrogen. mineral nitrogen is the basis of the total nitrogen deposition. 3.2. the effect of simulated nitrogen deposition on the net transformation flux of soil nitrogen in a temperate forest the variation in annual net mineralization flux of soil nitrogen in the control plot in the spruce­fir forest of the qinghai­tibet plateau from 2012 to 2013 was 5.58­8.71 n kg ha-1yr-1 which is lower than that reported by vestgarden et al. (2003) (-7.7 n kg ha-1 yr-1), blumfield et al. (2004) (13.4 n kg ha-1 yr-1) and brenner et al. (2005) (13.6­29.7 n kg ha-1 yr-1). this is also much lower than the annual net mineralization flux of the soil nitrogen in a european coniferous forest reported by schroeter et al. (2003) (30­90 n kg ha-1 yr-1) and the annual net mineralization flux of the soil nitrogen in a chinese subtropical forest reported by chen & jan (2007) (62.6 n kg ha-1 yr-1). clearly, the annual net mineralization flux of forest soil nitrogen may vary figure 1. seasonal changes in atmospheric temperature and precipitation in the forest. table 1. annual changes in different forms of nitrogen content in forest penetration rain. nh4 +-n no3 --n tin tn nh4 +-n / tin tin / tn kg n ha-1yr-1 % 2012 5.06 2.21 6.92 8.71 73.13 79.46 2013 2.93 0.44 3.38 5.58 86.83 60.48 figure 2. different forms of nitrogen input in different seasons of picea-abies from 2012 to 2013. g eo lo gi a c ro at ic a geologia croatica 72 / special issue148 with different regional atmospheric nitrogen depositions, different soil and forest types, and different experimental methods. in the field experiment, the control treatment showed that the net ammonification flux, net nitrification flux, and net mineralization flux of the nitrogen in the samples from 0­7cm soil layers and 0-15cm soil layers share similar seasonal variability. to be more specific, the net transformation flux of nitrogen in summers and autumns of 2012 and 2013 was a little higher than that in the springs and winters of the same years; but, the difference was not significant (figures 3 and 5). in the experimental plot with no nitrogen, the annual net mineralization fluxes of the nitrogen in the 0­15cm soil layers in 2013 were significantly higher than that in 2012 (p<0.05) (figure-4 and figure-6). with linear regression analysis, an equation with two unknowns was established to indicate the influence of temperature (t) and precipitation (p) on the net mineralization flux (y1) of the nitrogen in the 0-7cm soil layer: y1=(3.15±1.18)t+(5.49±7.97)p-(82.91±214.62).(r2=0.94, n=6, p<0.05) therefore, according to the regression determination coefficient (r2), it could be concluded here that the temperature is the key factor influencing seasonal variations in the net transformation flux of forest soil nitrogen (stenger et al., 1996; pajuste et al., 2003; xu, 2005). knoepp & vose (2007) reported that in a mixed broadleaf­conifer forest in the eastern u.s. the monthly accumulative net mineralization flux and monthly accumulative nitrification flux of temperate forest soil nitrogen increased significantly as the soil temperature and humidity rose. the soil temperature had a greater influence on the net mineralization flux of nitrogen and both the soil temperature and humidity were the reason for 83% variation in the net mineralization flux of soil nitrogen. pajuste et al. (2003) pointed out that temperature, humidity, and ph could together explain 70% of the variation in annual net ammonification flux of the soil nitrogen in a scots pine (pinus sylvestris) and norway spruce forest of east estonia of which the net ammonification flux of scots pine (pinus sylvestris) forest soil nitrogen had a significantly positive correlation with temperature (r2=0.69, p<0.0001). the annual net mineralization flux of the fir forest soil nitrogen in qinghai-tibet plateau was mainly manifested by the net ammonification flux which accounts for 76­89% of the net mine­ ralization flux. in 2013, the input of a high dose of kno3 significantly inhibited the proportion of net ammonification flux to net mineralization flux of the nitrogen in the 0­7cm soil layer. however, the input of nh4 +­n did not show any significant influence on the proportion of net ammonification flux to net mineralization flux of the nitrogen in the same soil layer. earlier research suggests that the nitrogen deposition increase was reduced or did not influence the proportion of net ammonification flux to total net mineralization flux of soil nitrogen. brenner et al. (2005) reported that the net ammonification flux accounts for 68.9% of figure 3. the effect of high nitrogen input on soil net ammonification, net nitrification, and net mineralization in different years. a-c: 0-7cm; d-f: 0-15cm; error bar is standard error for four repeated measurements. g eologia c roatica ge et al.: investigation of in situ soil nitrogen mineralization in a picea-abies forest on the tibet plateau: effects of increased nitrogen input 149 the total mineralization flux of the nitrogen in the 0­20cm soil layer in a high-latitude forest in the usa and the input of 100 n kg ha-1 yr-1 of nano3 caused the proportion to decrease to 31%. according to emmett et al. (1995), in a forest of the northern uk, the net ammonification flux accounts for 90% of the net mineralization flux in the 0­7cm soil layer and the input of 35 n kg ha-1 yr-1 of nh4no3 and the input of 70 n kg ha-1 yr-1 of nh4no3 caused the proportion to decrease to 85% and 75%, respectively. at the initial phase of the field experiment, the input of different doses of nh4 +­n significantly promoted (p<0.05) both the annual net ammonification flux and the annual net mineralization flux of the nitrogen in the 0­7cm and the 0­15cm soil layers; especially in the 0­15cm soil layer. the annual net ammonification flux and annual net mineralization flux of the nitrogen in the 0­7cm soil layer in the experiment plot applied with no3 --n showed a tendency to increase with the extension of the years of no3 --n application compared with the application of nh4 +-n (see figure-3 and figure-5). these results suggest that for the same site conditions, the influences from the input of nitrogen in different forms on forest topsoil nitrogen transformation flux might be different. previous research showed that a short period (e.g., 1 to 2 years) of simulated nitrogen deposition increase significantly promoted the net mineralization flux of forest soil nitrogen (emmett et al., 1995; sultana et al., 2004; brenner et al., 2005). the 14-year (from 1988 to 2002) simulated nitrogen deposition experiment conducted by mcnulty et al. (2005) on a redwood forest of the u.s. showed that the increase of nh4cl input significantly promoted the net mineralization flux of soil nitrogen in the first four years of the experiment. however, the promotion weakened gradually with the extension of the years of nh4cl application. by 1994, the nitrogen mineralization potential of the soil in the plot supplied with nitrogen was lower than that in the control plot and nitrogen deposition increase did not significantly influence the net mineralization flux of the soil nitrogen. it is evident that the increase in nitrogen input, especially nh4 +­n input, significantly promotes the net mineralization flux of soil nitrogen in a short period (e.g., from 1 to 3 years). however, the promotion gradually weakens with the extension of the years of nitrogen application. with the increase in nitrogen deposition, the net mineralization flux of soil nitrogen increases accordingly and the contribution rate of nitrogen deposition to net mineralization flux in the temperate old-growth forest is about 25%. magill et al. (2000) conducted a nine-year in-situ observation on the net mineralization flux of soil nitrogen in a mixed broadleaf­conifer forest in the eastern part of maine (usa). their results showed that both the input of a low dose (50 n kg ha-1 yr-1) and a high dose (150 n kg ha-1 yr-1) of nh4no3 significantly promotes the net mineralization flux of soil nitrogen. the promotion by application of the figure 4. the effect of high nitrogen input on soil net annual nitrogen mineralization in different years. a-c: 0-7cm; d-f: 0-15cm; error bar is standard error for four repeated measurements.* is significant level with contrast. g eo lo gi a c ro at ic a geologia croatica 72 / special issue150 ta bl e 2. p re vi ou s r ep or ts o n so il ne t n itr og en m in er al iz at io n in re gi on al fo re st e co sy st em s. fo re st ty pe g eo gr ap hi c p os iti on ph c/ n m et ho ds a so il de pt h n itr og en fe rti liz er s d ep os iti on fe rti liz er n et m in er al iz atio n n et ni tri fic at io n ye ar s re fe re nc es la tit ud e lo ng itu de (c m ) n k g ha -1 yr -1 pi ce a a bi es 56 °3 3’ n 13 °1 3’ e 4. 1 29 a 05 16 -30 2 d a g m a r, 2 00 3 pi ce a a bi es 56 °3 3’ n 13 °1 3’ e 3. 7 22 a 05 20 -90 pi ce a a bi es 50 °1 2’ n 11 °5 3’ e 3. 5 26 a 05 15 -35 ho op p in e 48 °1 2’ n 07 °1 1’ e 6 a 010 12 -13 .4 2 bl u m fi el d , 2 00 4 re d pr uc e 26 °3 1’ n 15 2° 3’ e 4. 1 19 .4 a 010 8. 4 -37 1. 5 2 su lt a n a , 2 00 4 a m er ic an b ee ch 44 °5 2’ n 68 °0 6’ e 4. 4 20 .2 a 010 25 .2 -66 3. 3 n or w ay sp ru ce 56 °2 9’ n 8° 24 ’e 33 b, c 05 20 -13 4 g u n d er se n , 1 99 8 56 °2 9’ n 8° 24 ’e 33 b, c 05 n h 4n o 3 20 35 24 n or w ay sp ru ce 35 °2 3’ s 14 8° 5’ e 30 .8 a 010 10 -12 .1 3 h o ss a in , 1 99 5 35 °2 3’ s 14 8° 5’ e 30 .8 a 010 u re a 10 10 0 24 .1 br ic hpi ne 62 °4 6’ n 30 °5 8’ e 4. 7 c 27 -87 52 1 re g in a , 1 99 7 br ic hpi ne 62 °4 6’ n 30 °5 8’ e 4. 8 c k n o 3 27 10 0 10 7 60 br ic hpi ne 62 °4 6’ n 30 °5 8’ e 4. 5 c n h 4c l 27 10 0 12 9 63 br ic hpi ne 62 °4 6’ n 30 °5 8’ e 4. 8 c u re a 27 10 0 91 74 pi ce a a bi es 58 °4 ’n 12 °0 1’ e b n h 4n o 3 12 35 27 -4 6 g u n d er se n , 1 99 8 p. ab ie s 56 °2 9’ n 8° 24 ’e b n h 4n o 3 18 35 13 0. 01 p.s itc he ni se s 53 °1 ’n 4° e b n h 4n o 3 17 35 68 7 sc ot s p in e 59 °5 4’ n 8° 34 ’e 3. 7 c 014 10 --7 .7 2 v es tf a rd en , 2 00 3 sc ot s p in e 59 °5 4’ n 8° 34 ’e 3. 7 c 014 n h 4n o 3 10 30 -1 7. 2 sc ot s p in e 59 °5 4’ n 8° 34 ’e 3. 7 c 014 n h 4n o 3 10 90 89 .8 m as so n 10 4° 4’ n 29 °3 8’ e 3. 5 17 .9 a 015 38 -62 .6 36 .4 1 ch en , 2 00 7 pi ne 11 2° 3’ n 27 °5 5’ e 3. 9 15 .2 a 015 44 -52 .4 33 .6 pi ne 42 °3 ’n 72 °1 ’w 3. 2 23 .7 a 8 -60 -1 00 9 m a g il l, 2 00 0 pi ne 42 °3 ’n 72 °1 ’w 3. 2 23 .7 a n h 4n o 3 8 50 51 -1 55 pi ne 42 °3 ’n 72 °1 ’w 3. 2 23 .7 a n h 4n o 3 8 15 0 75 -1 90 si tk a s pr uc e 53 °1 2’ n 4° w 31 c 28 -67 .7 7 2. 5 em m et t, 1 99 5 w hi te sp ru ce 53 °1 2’ n 4° w 31 c n h 4n o 3 28 75 89 .6 22 .3 w hi te sp ru ce 64 °4 5’ n 14 8° 2’ w 7. 6 17 .3 a 020 19 -29 .7 2 ri ch a rd , 2 00 5 w hi te sp ru ce 64 °4 5’ n 14 8° 2’ w a 020 n an o 3 19 10 0 48 .4 de ci du ou s 45 °2 2’ n 79 °0 7’ w 4. 1 19 c 010 9. 6 -53 .7 27 .5 1 k ev in , 1 99 9 co ni fe rm ix ed 45 °2 2’ n 79 °0 7’ w 4. 2 18 c 010 9. 6 -46 .5 1. 4 pe at la nd 45 °2 2’ n 79 °0 7’ w 3. 7 27 c 010 9. 6 -15 .4 0. 5 ch in es e p in e 40 °0 0’ n 11 5° 3’ e b 015 32 .5 -22 .7 1 su b , 2 00 1 b 015 -55 .5 n or w ay sp ru ce 51 °3 1’ n 93 4e 26 a 05 33 -34 16 11 m a ri fe , 2 00 4 re d sp ru ce 43 °2 6’ n 72 °2 7’ w c 05 16 -10 14 st ev en , 2 00 5 re d sp ru ce 43 °2 6’ n 72 °2 7’ w c 05 n h 4n o 3 16 15 .7 18 -5 0 re d sp ru ce 43 °2 6’ n 72 °2 7’ w c 05 n h 4n o 3 16 31 .4 850 a a fo r b ur ie d ba g m et ho d， b fo r c lo se -t op tu be in cu ba tio n te ch ni qu e， c fo r r es in -c or e te ch ni qu e g eologia c roatica ge et al.: investigation of in situ soil nitrogen mineralization in a picea-abies forest on the tibet plateau: effects of increased nitrogen input 151 high dose was much more obvious and the contribution rate of exogenous nitrogen input to the net mineralization flux of soil nitrogen was about 64%. vestgarden et al. (2003) reported that 34% of the net mineralization flux of scots pine (pinus sylvestris) forest soil nitrogen in northern norway is attributed to exogenous nitrogen application. another observed result by mcnulty et al. (2005) showed that the average contribution rate of nitrogen deposition increased the net mineralization flux of forest soil nitrogen for about 21% over a 12 year observation period. they also found the contribution rates of nitrogen deposition to the net mineralization flux of the forest soil nitrogen in different areas were significantly different. this may be closely related to forest type, climatic factors (such as annual precipitation and average annual temperature), and soil attributes. 3.3. prediction of the effect of simulated nitrogen deposition on the annual net mineralization flux of forest soil nitrogen in different areas until now, both chinese and international research on the response of soil nitrogen transformation in forest ecosystems to atmospheric nitrogen deposition was mainly conducted in sample plots and communities which were relatively small in scale. the focus of this research was mainly on the investigation of the mechanism of net mineralization flux of soil nitrogen. investigation of the influence of nitrogen input and its synergistic factors on the net mineralization flux of forest soil nitrogen from the perspective of the regional scale was not addressed properly in the literature. in reality, the net mineralization fluxes of soil nitrogen show great differences in different forest ecosystems due to different vegetation, soil matrix, and climatic factors. hence, on a global scale, for a deep understanding of global forest soil nitrogen transformation patterns and for a response to global warming, it is extremely essential to establish the law leading to zonal distribution of net mineralization of forest soil nitrogen as well as its influencing factors. in the section, the results of the current research on the influence of nitrogen deposition increase on main soil carbon and nitrogen processes in regional forest ecosystems is summarized. the correlation between environmental factors such as climatic and biotic factors is discussed in table 1. the results show that the annual net mineralization flux of forest soil nitrogen significantly increases linearly with the increase in atmospheric nitrogen deposition. in addition, the contribution rate of nitrogen deposition to the annual net mineralization flux of the forest soil nitrogen is about 48% (figure 7.). according to chen & jan (2007), in east china, when the nitrogen deposition was 25-49 n kg ha-1 yr-1, the net mineralization flux of subtropical forest soil figure 5. th effect of low nitrogen input on soil net ammonification, net nitrification, and net mineralization in different years. a-c: 0-7cm; d-f: 0-15cm; error bar is standard error for four repeated measurements. g eo lo gi a c ro at ic a geologia croatica 72 / special issue152 nitrogen was 52­62 n kg ha-1 yr-1, and the contribution rate of nitrogen deposition to the net mineralization flux of soil nitrogen was 34%. pérez et al. (1998) studied the annual net mineralization flux of temperate old­growth forest soil nitrogen in north america. they reported that the net mineralization flux of hinoki cypress (chamaecyparis obtuse) forest soil nitrogen was 20-23 n kg ha-1 yr-1, and that of beech forest soil nitrogen was 31-37 n kg ha-1 yr-1. a long period of atmospheric nitrogen deposition increase would reduce the carbon-to-nitrogen (c/n) ratio of the forest soil in the northern hemisphere and then the promoted soil nitrogen mineralization flux. based on gundersen (1998), when atmospheric nitrogen deposition was 13­59 n kg ha-1 yr1, the net mineralization flux of european coniferous forest soil nitrogen increased with the increase in nitrogen deposition. the contribution rate of nitrogen deposition to the net mineralization flux of soil nitrogen was 38%. 4. conclusion net ammonification accounts for about 76­89% of the net mine­ ralization; while it decreases to 64-83% in kno3 treatments. the net n mineralization rate increased with nitrogen input, especially in nh4+ --n treatments (p<0.05). however, this promoting role decreased over time in longer experiments. at the highest (nh4)2so4 addition, the net ammonification and net mineralization rate increased more clearly in the humus (0-7cm) than in the uppermost mineral layer (0-15 cm). a compilation of previous studies conducted on soil net mineralization from forests under different environmental conditions was evaluated for the effects of atmospheric n deposition and environmental factors, annual figure 6. the effect of low nitrogen input on soil net annual nitrogen mineralization in different years. a-c: 0-7cm; d-f: 0-15cm; error bar is standard error for four repeated measurements. * is significant level with contrast. figure 7. the relationship between net nitrogen mineralization fluxes with annual atmospheric nitrogen deposition in forest ecosystem. solid circles are data points for the current observations, open circles are data points for previous in situ observational data. g eologia c roatica ge et al.: investigation of in situ soil nitrogen mineralization in a picea-abies forest on the tibet plateau: effects of increased nitrogen input 153 precipitation, and annual temperature on annual fluxes of net nitrogen mineralization in forest soils in the global scale. the results showed that increased atmospheric n deposition significantly enhanced the soil net nitrogen mineralization rate. the variations in atmospheric n deposition account for 48% of the variation in rates of soil net nitrogen mineralization across the forests. acknwledgement dr. yongjie wang, boqing xu and jinlong chang of the southeast mountain environment comprehensive observation station of chinese academy of sciences assisted with sample collection and analysis. thanks also to employees of the institute of tibetan plateau research chinese academy of sciences for assistance and their cooperation in the experiments. references aber, j.d. & magill, a.h. (2004): chronic nitrogen additions at the harvard forest: the first 15 years of a nitrogen saturation experiment.– forest ecology and management, 196, 1–5. arnold, j., corre, m.d. & veldkamp, p. (2008): cold storage and laboratory incubation of intact soil cores do not reflect in­situ nitrogen cycling rates of tropical forest soils.– soil biology & biochemistry, 40, 2480–2483. doi: 10.1016/j. soilbio.2008.06.001 bhogal, a., hatch, d.j. & shepherd, m.a. (1999): comparison of methodologies for field measurement of net nitrogen mineralization in arable soils.– plant and soil, 207, 15–28. blumfield, t.j., xu, z.h. & saffigna, p.g. (2004): carbon and nitrogen dynamics under windrowed residues during the establishment phase of a secondrotation hoop pine plantation in subtropical australia.– forest ecology and mana­ gement, 200, 279–291. brenner, r.e., boone, r.d. & ruess, r.w. (2005): nitrogen additions to pristine, high-latitude, forest ecosystems: consequences for soil nitrogen transformations and retention in mid and late succession.– biogeochemistry, 72, 257–282. doi: 10.1007/s10533-004-0356-y burton, j., chen, c.r., xu, z. h. & ghadiri, h. (2007): gross nitrogen transformations in adjacent native and plantation forests of subtropical australia.– soil biology & biochemistry, 39, 426–433. doi: 10.1016/j.soilbio.2006.08.011 chen, x.y. & jan, m. (2007): indicators for nitrogen status and leaching in subtropical forest ecosystems, south china.– biogeochemistry, 82, 165–180. doi: 10.1007/ s10533-006-9061-3 corre, m.d. & lamersdorf, n.p. (2004): reversal of nitrogen saturatioin after long­term deposition reduction: impact on soil nitrogen cycling.– ecology. 85/11, 3090–3140. david, m. b., cupples, a. m., lawrence, g. b., shi, g., vogt, k. & wargo, p.m. (1998): effect of chronic nitrogen additions on soil nitrogen fractious in red spruce stands.– water, air, and soil pollution, 105, 183–192. devito, k.j., westbrook, c.j. & schiff, s.l. (1999): nitrogen mineralization and nitrigicatioin in upland and peat land of rest soils in two canadian shield catchments.– canadian journal of forest research, 29, 1793–1804. emmett, b.a., brittain, s.a., hughes, s. & kennedy, v. (1995): nitrogen additions (nano3 and nh4no3) at aber forest, wales: ii. response of trees and soil nitrogen transformations.– forest ecology and management, 71, 61–73. doi: 10.1016/0378-1127(94)06084-v fang, y.t., mo, j.m. & gundersen, p. (2004): nitrogen transformations in forest soils and its responses to atmospheric nitrogen deposition: a review.– acta ecologica sinica, 24/7, 1523–1531. gundersen, p. (1998): effects of enhanced nitrogen deposition in a spruce forest at klosterhede, denmark, examined by moderate nh4no3 addition.– forest eco logy and management, 101, 251–268, doi: 10.1016/s0378­1127(97)00141­2 gundersen, p., emmett, b.a., kjonaas, o.j., koopmans, c.j. & tietema, a. (1998): impact of nitrogen deposition on nitrogen cycling in forests: a synthesis of nitrex data.– forest ecology and management, 101, 37–55. doi: 10.1016/s0378-1127(97)00124-2 hatch, d. j., bhogal, a., lovell, r. d., shepherd, m.a. & jarvis, s.c. (2000): comparison of different methodologies for field measurement of net nitrogen mineralization in pasture soils under different soil conditions. – biology and fertility of soils, 32, 287–293. doi: 10.1007/s003740000250 hossain, a.k.m.a., raison, r.j. & khanna, p.k. (1995): effects of fertilizer application and fire regime on soil microbial biomass carbon and nitrogen, and nitrogen mineralization in an australian subalpine eucalypt forest.– biology and fertility of soils, 19, 246–252. doi: 10.1007/bf00336167 jussy, j.h., belgrand, m.c., dambrine, e., ranger, j., zelelr, b. & bienaime, s. (2004): n deposition, n transformation and n leaching in acid forest soils.– biogeochemistry, 69, 241–262. doi: 10.1023/b:biog.0000031050.13663.82 kim, h.t. (1995): soil sampling, preparation and analysis. new york: marcel dekker. knoepp, j.d. & vose, j.m. (2007): regulation of nitrogen mineralization and nitrification in southern appalachian ecosystems: separating the relative importance of biotic vs. abiotic controls.– pedobiologia, 51, 89–97. doi: 10.1016/j.pedobi.2007.02.002 li, m.r. & sha, l.q. (2005): soil nitrogen mineralization under different land use patterns in xishuangbanna.– chinese journal of applied ecology, 16/1, 54–58. magill, a.h., aber, j.d., berntson, g.m.,mcdowell, h. nadelhoffer, k.j., melillo, j.m. & steudler, p. (2000): long–term nitrogen additions and nitrogen saturation in two temperate forests.– ecosystems, 3, 238–253. doi: 10.1007/s100210000023 magill, a.h., downs, m.r., nadelhoffer, k.j., hallett, r. & aber, j.d. (1996): forest ecosystem response to four years of chronic nitrate and sulfate additions at bear brooks watershed, maine, usa.– forest ecology and management. 1996, 84/1–3, 29–37. doi: 10.1016/0378­1127(96)03775­9 mcnulty, s.g., boggs, j., aber, j.d., rustad, l. & magill, a. (2005): red spruce ecosystem level changes following 14 years of chronic n fertilization.– forest ecology and management, 219, 279–291. meng, y., xue, j. y. & sha, l. q. (2001): variations of soil nh4 +–n, no3 ––n and mineralization under different forests in xishuangbanna, southwest china.– acta phytoecologica sinica, 25/1, 99–104. ouyang, x. j., zhow, g. y. & huang, z. l. (2008): effect of simulated acid rain on potential carbon and nitrogen mineralization in forest soils.– pedosphere, 18/4, 503–514. pajuste, k. & frey, j. (2003): nitrogen mineralization in podzol soils under boreal scots pine and norway spruce stands.– plant and soil, 257, 237–247. pérez, c.a., hedin, l.o. & armesto, j.j. (1998): nitrogen mineralization in two unpolluted old–growth forests of contrasting biodiversity and dynamics.– ecosystems, 361–373. regina, k., nykanen, h., maljanen, m., silvola, j. & martikainen, p. j. (1997): emission of n2o and no and net nitrogen mineralization in a boreal forested peatland treated with different nitrogen compounds.– can. j. for. res., 28, 132–140. richter, a., burrows, j.b., nüss, h, granier, c. & niemeier, u. (2005): increase in tropospheric nitrogen dioxide over china observed from space.– nature, 437, 129–132. schroeter, d., wolters, v. & de ruiter, p.c. (2003): n mineralization in the decomposer food webs of a european forest transect.– oikos, 102, 294–308. stenger, r., priesack, e. & beese, f. (1996): in situ studies of soil mineral n fluxes: some comments on the applicability of the sequential soil coring method in arable soils.– plant and soil, 183, 199–211. su, b., han, x.g. & qu, c.m. (2001): net nitrogen mineralization and nitrification in one pure pine forest and one pine–oak mixed forest in dongiling mountainous region.– acta phytoecologica sinica, 25/2, 195–203. sultana, j., fernandez, i.j., lindsey, e.r. & dail, b. (2004): decadal responses in soil n dynamics at the bear brook watershed in maine, usa.– forest ecology and management, 189, 189–205. vestgarden, l.s., selle, l.t. & stuanes, a.o. (2003): in situ soil nitrogen mineralization in a scots pine (pinus sylvestris l.) stand: effects of increased nitrogen input.– forest ecology and management, 176, 205–216. xu, z. z. & zhou, g. s. (2005): effects of water stress on photosynthesis and nitrogen metabolism in vegetative and reproductive shoots of leymus chinensis.– photosynthetica, 43, 29–35. zhou, c.p. & ouyang, h. (2001): effects of temperature on nitrogen mineralization at optimum and saturated soil water content in two types of forest in changbai mountain.– acta ecologica sinica, 21/9, 1469–1473. zhou, c.p., ouyang, h. & pei, z.y. (2003): net soil nitrogen mineralization in chinese forest ecosystems.– acta phytoecologica sinica, 27/2, 170–176. 2017 | 70/1 | 11–25 | 5 figs. | 2 pls. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the aim of this study was primarily to determine the microfacies properties of the čikola river canyon carbonate deposits rich in larger benthic foraminifera (lbf). these determined forami­ niferal assemblages and their ecological requirements combined with the study of other carbonate-producing biota (corals, bryo­ zoans, echinoids, molluscs, coralline red algae), enabled the definition of the palaeoenvironmental settings of the lower eocene deposits known as the foraminiferal limestones. the studied section is located in the outer dinarides, the unit being composed mainly of carbonate rocks, ranging in age from the upper carboniferous to the eocene (vlahović et al., 2005). the studied deposits belong to the more or less continu­ ous palaeogene belt oriented nw−se along the ne adriatic coast (ćosović et al., 2008a) (fig. 1), i.e. to the north dalmatian foreland basin (babić & zupanič, 1983, 2007, 2012; mrinjek et al., 2012). the lower palaeogene carbonate succession in the area is underlain by karstified upper cretaceous rocks (subaerial expo­ sure commenced during the campanian; mamužić, 1975). the kozina beds, the oldest palaeogene deposits, which originated early eocene evolution of carbonate depositional environments recorded in the čikola canyon (north dalmatian foreland basin, croatia) jelena španiček1, vlasta ćosović1, ervin mrinjek1 and igor vlahović2 1 university of zagreb, faculty of science, department of geology, horvatovac 102a, hr-10000 zagreb, croatia; (corresponding author: jelena.spanicek@geol.pmf.hr) 2 university of zagreb, faculty of mining, geology and petroleum engineering, department of geology and geological engineering, pierottijeva 6, hr-10000 zagreb, croatia doi: 10.4154/gc.2017.05 abstract the stratigraphic succession in the čikola canyon (part of the north dalmatian foreland basin) was studied in detail to describe both the sedimentological characteristics and fossil assemblages of the lower eocene deposits during the initial stage of the foreland basin formation. the north dalmatian basin now represents a part of the outer dinarides, and was developed in front of the evolving dinaric structures by tectonic deformation and marine transgression of an emerged and denuded mesozoic adriatic carbonate platform (adcp). during the initial phase, a distal ramp of a foreland basin was formed, characterised by carbonate sedimentation, lasting until the middle eocene. in a studied section more than 300 m thick, porcelaneous foraminifera, alveolina, orbitolites and complex miliolids (idalina, periloculina) prevail, associated with conical agglutinated forms, nummulitids and red algae. these samples belong to the sbz 11–12 (ypresian), according to occurrences of alveolina decastroi, alveolina cremae, alveolina multicanalifera and coskinolina liburnica. two main lithological units have been described: 1) mudstones to wackestones with sporadic occurrences of ostracods and charophyceae, deposited in restricted lagoonal settings with several episodes of freshwater influences, and 2) foraminiferal packstones to grainstones with complex miliolids, alveolinids, corallinacean algae and nummulitids, deposited within inner and middle ramp settings. palaeogene deposition of ramp carbonates in the outer dinarides area was mainly controlled by the continuous compressional tectonics, and the deposits today appear in more or less discontinuous outcrops. palaeogene transgression occurred at different times over various parts of the former carbonate platform area, and subsequent carbonate sedimentation was characterised by deposition in similar environments during different time intervals over spatially restricted carbonate ramps controlled by synsedimentary tectonics. article history: manuscript received november 08, 2016 revised manuscript accepted february 25, 2017 available online february 28, 2017 keywords: larger benthic foraminifera, microfacies, palaeoenvironment, foraminiferal limestones, north dalmatian foreland basin, lower eocene locally within restricted lagoons are marked by a shift from fresh and brackish-water environments to a fully marine regime in the area. during the eocene the shallow-marine (neritic) carbonate succession rich in lbf, known as the foraminiferal limestones, was deposited within carbonate ramp environments (drobne et al., 1991; babić & zupanič, 2016 with references therein) over either the kozina beds or directly onto karstified cretaceous deposits. the ramp deposits pass upward into glauconite-bearing marly transitional beds, overlain in some areas by a turbiditic succession of flysch and/or by a thick succession of promina beds (mrinjek et al., 2012). the most important characteristic of the studied palaeogene carbonate deposits are the abundance and diversity of the lbf. they are an endosymbiont-bearing (lee, 1998; hallock, 1999, and references therein), highly diversified and specialized group of organisms with specific environmental preferences re­ garding temperature, salinity, water energy, light intensity, and substrate type, numerous in the photic zone of oligotrophic tropical and subtropical seas (hottinger, 1983, 1997; boud­ agher-fadel, 2008). this makes them, apart from being ma­ jor carbonate producers, excellent shallow-water environmental/ palaeoenvironmental indicators (hottinger, 1983, 1997; ho­ g eo lo gi a c ro at ic a geologia croatica 70/112 henegger, 2004, 2005), because their presence indicates spe­ cific water temperature, salinity, light conditions, energy and seabottom conditions. based on the abundance of specific groups of lbf, the foraminiferal limestones in the outer dinarides are often informally subdivided into separate members: miliolid-, alveolinid-, nummulitid-, and/or orthophragminid limestones. deposits of each member originated under different palaeoenvi­ ronmental conditions, and their spatial and temporal distribution figure 1. (a) simplified location map of the palaeogene deposits in the dinarides (modified after ćosović et al., 2008a; drobne et al., 2011) with the location of geological columns from fig. 5, (b) geological map (modified after mamužić, 1971; ivanović et al., 1973, 1977; ćosović et al., 2008a; drobne et al., 2011; mri­ njek et al., 2012), and (c) panoramic view of the studied čikola section. late cretaceous rudist limestones are unconformably overlain by the studied kozina beds and lower eocene foraminiferal limestones, which are conformably overlain by the promina beds (modified after mrinjek et al., 2012). g eologia c roatica španiček et al.: early eocene evolution of carbonate depositional environments recorded in the čikola canyon ... 13 suggests an overall deepening of the sedimentary settings during the early eocene and early middle eocene. our results could shed additional light on the deposition of the foraminiferal limestones, and provide more data about the evolution of the northern dalmatian foreland basin during the eocene. new data will help in completing the picture of the evo­ lution of the eocene shallow-water (neritic) sedimentary system of the outer dinarides, including a discussion of palaeogeograph­ ical terminology. 2. geological setting and stratigraphy the studied area represents part of the north dalmatian foreland basin developed in front of the evolving dinaric structures by tectonic deformation and marine transgression of an emerged and denuded mesozoic adriatic carbonate platform (adcp). during the initial phase, a ramp was formed as a distal part of a foredeep in the dinaric foreland basin system, and carbonate sedimenta­ tion existed on a flank of a broad forebulge until the middle eo­ cene (babić & zupanič, 2008, 2012). deposition during the palaeogene was significantly control­ led by tectonic deformation caused by the propagation of the di­ naric orogeny towards the sw. the palaeogene shallow-marine (neritic) carbonates were deposited on a carbonate ramp (ćosović et al., 2008a), named the palaeogene adriatic carbonate platform (pgadcp) by drobne et al. (2009, 2011). the upward deepening of the carbonate ramp produced a 220 m thick succes­ sion (ivanović et al., 1976) of carbonates in the studied region. the succession is composed of palustrine and marginal marine carbonates, often referred to as the kozina beds overlain by neritic deposits known as the foraminiferal limestones (for general overview see vlahović & velić, 2009). deposition of the overlying transitional beds (ćosović et al., 2008a) and turbiditic deposits (flysch) started when ramp carbonate production was unable to keep pace with subsidence. the subsequent shal­ lowing of depositional environments is recorded in the small pig­ gyback sub-basins within the promina basin (korbar 2009; mrinjek et al., 2012), where the succession of promina beds (schubert, 1904, 1908; mamužić, 1971; ivanović et al., 1973, 1977) of the middle eocene to oligocene age were deposited in thickness of up to 2000 m (babić & zupanič, 2012; mrinjek et al., 2012). 3. materials and methods the studied section is located in the well-exposed road-cut along the local road passing across the čikola river canyon (fig. 1b, c). the geographic coordinates of the first and last sampled intervals are 43°50’8.9”n, 16°2’49.3”e and 43°50’20.4”n, 16°2’58.2”e, re­ spectively. the section encompasses a 310 m thick carbonate suc­ cession which was measured and sampled in detail to document both the sedimentological characteristics and fossil assemblages (fig. 2). over 300 samples were collected for microfacies and micro­ palaeontological study and more than 270 thin sections represent­ ing various microfacies types were analysed. a total of 12 micro­ facies types have been defined based on lbf assemblages and sedimentary textures. lbf assemblages were investigated in thin sections in order to determine the age of the deposits, applying the shallow ben­ thic zones (sbzs) of serra-kiel et al. (1998). taxonomic iden tification of foraminiferal tests was based on random thin sections and when sections allowed, identification to species level was done, using key literature for alveolinids (hottinger, 1960; drobne, 1977), miliolids (drobne, 1974, 1985), and agglutinated conical foraminifera (hottinger & drobne, 1980; vecchio & hottinger, 2007). carbonate microfacies were distinguished according to dunham’s (1962) classification modified by embry & klovan (1971). for the microfacies analysis the methods of wilson (1975) and flügel (2010) were applied. in order to study environmental conditions, the visual examination and semi-quantitative analysis of lithology, grain types (biogenic or abiogenic), textures and fossil assemblages was performed. the modal distribution of components in thin sections was estimated by using a point-counting method (flügel, 2010). on each examined thin section, a two-dimensional grid of 1 cm2 was mark ed, and each grain within a grid was counted. from there, an estimated volume of a given grain type proportional to the counted numbers of a particular grain type was calculated. in de­ scriptions of identified microfacies, to simplify the results, esti­ mated volumes of particular grain types are presented semi-quan­ titatively by four subgroups: ‘no grains’, ‘rare grains’ (volume less than 15 %), ‘common grains’ (15 to 49 %), and ‘abundant grains’ (volume over 50 %). the microfacies types and foraminiferal assemblages enabled interpretation of the palaeoenviron­ mental conditions of the studied deposits similar to existing car­ bonate-ramp models (buxton & pedley, 1989; burchette & wright, 1992; geel, 2000; pomar, 2001; romero et al., 2002; bassi, 2005; bosence, 2005; zamagni et al., 2008; tomassetti et al., 2016). pomar’s (2001) subdivision of shallow-water carbonate environments from euphotic to oligo­ photic ones was also applied. 4. results 4.1. stratigraphy of the čikola section the palaeogene deposits in the studied čikola section (figs. 1, 2) may be divided into two stratigraphic units, s1 and s2, then fur­ ther subdivided into five sub-units (s1a, s1b, s2a, s2b and s2c), based on their fossil content (mainly foraminifera) and sedimen­ tary textures. the s1 unit transgressively overlies massive light-coloured upper cretaceous rudist-bearing limestones. the non-deposi­ tional phase between the upper cretaceous and palaeogene de­ posits is not easily recognizable in the field, since in the studied section it is not represented by any visible angular unconformity or infillings of continental deposits, and even karstification is not clearly visible everywhere. the detailed studies of thin sections reveal a reduction of fossils towards the youngest cretaceous rocks, and the presence of microcodium sp. aggregates in over­ lying beds, which are typical for the early stages of palaeosol de­ velopment in many peri-tethyan sections (košir, 2004). the oldest palaeogene deposits, stratigraphic unit s1, are composed of an alternation of well-bedded wackestones to pack­ stones and thin-bedded mudstones to wackestones. at the begin­ ning of a succession, the thin-bedded limestones are intercalated with a few cm thick coal layers. the lower part of s1 unit, the s1a, is characterised by a specific fossil content (gastropods, cha­ rophyceae and ostracods), while in the upper, s1b unit, the de­ creasing abundance of ostracods and gastropods is related to the increasing abundance of small miliolids and discorbids. the lower part of the overlying stratigraphic unit s2 consists of well-bedded foraminiferal wackestones to packstones with a rich lbf assemblage, whereas a massive appearance characterises deposits in the upper part of the unit. in the lowermost part – the g eo lo gi a c ro at ic a geologia croatica 70/114 figure 2. studied stratigraphic column of the čikola section showing the lithology, identified biozones (sbz after serra­kiel et al., 1998) and distribution of the microfacies types mft 1 to mft 12 (left), and position of the studied section within a generalized stratigraphic column of the upper cretaceous–eocene succession in the čikola canyon, northern dalmatia (mrinjek et al., 2012) (right). g eologia c roatica španiček et al.: early eocene evolution of carbonate depositional environments recorded in the čikola canyon ... 15 s2a unit – miliolids dominate, while the middle part (the s2b unit) has a diverse foraminiferal assemblage: miliolids, alveolinids, ag­ glutinated conical foraminifera and orbitolites sp. in the upper part of the unit, s2c, massive coarse-grained foraminiferal pack­ stones occur with lenticular-shaped nummulites, fragments of zooaxanthellate corals (z-corals) and corallinacean red algae (in­ cluding small rhodoliths) and rare orthophragminids. the top of the čikola section is conformably overlain by massive mudstone beds with thin streaks, normal-graded interlaminae and lenses of silt or very fine-grained sand, interpreted as initial fine-grained subneritic deposits of the promina beds (mrinjek et al., 2012). 4.2. facies association and microfacies types regarding the composition of foraminiferal assemblages and as­ sociated biota as well as sedimentary textures, the studied suc­ cession has been divided into twelve microfacies types, mft 1 to mft 12 (fig. 2). 4.2.1. mft 1 – non-fossiliferous mudstone to wackestone microfacies mft 1 is composed of mudstones characterised by a lack of fossils, more or less intense recrystallization, often com­ mon scattered dolomite crystals, and locally visible microcodium sp. clusters (pl. 1, fig. 1). interpretation: carbonates of the mft 1 microfacies were deposited in a shallow, inner ramp setting, where episodes of sub­ aerial exposure (as indicated by microcodium sp.) occurred. a lack of fossils characterised supratidal conditions within an inner ramp setting. this microfacies overlays the upper cretaceous rudist-bear­ ing limestones, and represents initial deposition over a regional unconformity (cretaceous to palaeogene stratigraphic hiatus). 4.2.2. mft 2 – ostracod mudstone to wackestone mft 2 consists of mudstones to wackestones containing com­ mon to abundant ostracod shells, common decastronema bara­ ttoloi (de castro) cyanobacterial filaments and rare charophy­ ceae (pl. 1, fig. 2). samples with abundant ostracods often show lamination. interpretation: the low-diversity fossil assemblage composed of thin-shelled ostracods, charophyceans and cyanobacteria sug­ gests episodic fresh-water influxes. the common presence of d. barattoloi, known as a pioneering organism in modifying the envi­ ronments to become more suitable for other organisms (ćosović et al., 2008b), supports such an interpretation. these described con­ ditions are typical of low-energy, protected brackish lagoons. this microfacies is typical for the basal part of the čikola section, the s1a stratigraphic unit, representing the oldest palae­ ogene deposits in the studied area (fig. 2). 4.2.3. mft 3 – dolomitized gastropod wackestone to packstone mft 3 is represented by wackestones to packstones (pl. 1, fig. 3). skeletal particles comprise abundant gastropods (stromatop­ sis sp. and cosinia sp.) and common charophyceae. the gastro­ pod shells are often compressed, fragmented, and intraskeletal pores are infilled by fine-grained wackestone to packstone. finegrained micritic matrix is often recrystallized, with common to abundant dolomite crystals scattered in the matrix or within in­ terparticle cement. interpretation: the presence of charophyceae and gastro­ pods indicate a freshwater influence, thus deposition probably took place in a brackish environment, whereas the micritic ma­ trix suggests a low turbulence environment. this microfacies occurs in the first 30 m of the čikola sec­ tion (s1a stratigraphical unit) and contains eight coal intercala­ tions, each a few cms in thickness (fig. 2). 4.2.4. mft 4 – bioturbated miliolid mudstone to wackestone mft 4 consists of mudstones to wackestones. the micritic ma­ trix is locally recrystallized, and numerous voids are partly filled with micrite (due to intense bioturbation) and/or sparite. bioclasts are rare to common, represented mostly by foraminifera such as abundant tests of discorbids, rare to common miliolids (quinque­ loculina sp., spirolina sp., pyrgo sp., triloculina sp., and idalina sp.), cribrobulimina sp., and ostracods (pl. 1, fig. 4). small, mm-sized voids filled with sparitic cement and engulfed in thick, micritic coatings, have spherical, subspherical and/or tubular shapes, are often clustered together, without any apparent pattern or orientation. voids with similar form and dimensions could be interpreted as tubular fenestral voids (cf. flügel, 2010). interpretation: the sedimentological and palaeontological features imply deposition in a very shallow, low-energy, restrict ed marine environment, where small epiphytic foraminifera (small miliolids) and discorbids thrived. occurrences of agglutinated conical foraminifera, related to protected, relatively nutrient-rich lagoonal environments (geel, 2000) support this environmental interpretation. this microfacies, together with mft 3, is a dominant micro­ facies in the lower 45 m of the čikola section, but it occurs throughout the entire čikola section, especially in stratigraphic units s2a and s2b to the 175 m of the čikola section (fig. 2). 4.2.5. mft 5 – conical agglutinated foraminiferal packstone the main characteristic of mft 5 is the abundance and diversity of conical agglutinated foraminifera (pl. 1, fig. 5; pl. 1, fig. 6): cribrobulimina cf. carniolica, pseudochrysalidina alva (silvestri), pfendericonus makarskae (van soest) and coskino­ lina liburnica (stache). other common benthic foraminifera are alveolinids and miliolids (including periloculina dalmatina drobne; pl. 1, fig. 5). interpretation: according to hottinger (1983, 1997), vecchio & hottinger (2007) and afzal et al. (2011) conical agglutinated foraminifera occupied soft muddy sea-bottom at depths just below the tidal level. thus, this microfacies is in­ terpreted as having been deposited in the protected, low-energy, shallowest parts of the innermost ramp. this microfacies occurs in the stratigraphic unit s2b of the čikola section. the first occurrence is at around 80 m and it is present almost until the end of the section (fig. 2). 4.2.6. mft 6 – miliolid wackestone to packstone the dominant lithology within mft 6 are fine-grained wacke­ stones to packstones (pl. 1, fig. 7), in which the micritic matrix is occasionally partially recrystallized. this microfacies is cha­ racterised by the abundance of both small and complex miliolids: quinqueloculina sp., spirolina sp., pyrgo sp., triloculina sp., and idalina cf. sinjarica, as well as the rare to common presence of agglutinated conical foraminifera, cribrobulimina cf. carniolica. interpretation: sedimentological and palaeontological charac teristics (the proportion of smaller and larger miliolids and agglutinated conical foraminifera – geel, 2000; romero et al., 2002; vecchio & hottinger, 2007, afzal et al., 2011) of the mft 6 microfacies suggests deposition in lowto moderate-energy environments of the inner ramp. g eo lo gi a c ro at ic a geologia croatica 70/116 this microfacies occurs for the first time at c. 35 m from the base of the čikola section within the stratigraphic unit s1b, but prevails at the beginning of stratigraphic unit s2 (within subunit s2a), and continues up to the 110 m mark in the čikola section (fig. 2). 4.2.7. mft 7 – alveolinid-miliolid packstone mft 7 is represented by poorly-sorted packstones with a finegrained micritic (rarely coarse-grained) matrix (pl. 1, fig. 8; pl. 2, fig. 1). this microfacies is characterised by an abundance of porcelaneous foraminifera, mainly alveolinids and miliolids: al­ veolina decastroi scotto di carlo, a. cremae checchia -rispoli, a. multicanalifera drobne, a. levantina hottinger, idalina cf. sinjarica, spirolina sp., quinqueloculina sp. and pyrgo sp. orbitolites complanatus lamarck tests are also common. the foraminiferal tests bear marks of bioerosion, and in some cases, the final whorls are missing. the occurrences of some ‘deformed’ orbitolitid tests (forms with additional perpen­ dicular disks) are indicative of ‘extreme’ conditions (hottinger, 1983) (pl. 1, fig. 8). other bioclasts include rare tests of rotaliids, rare to abundant agglutinated conical foraminifera, cribrobulimina sp., and pseudochrysalidina alva (silvestri), aborescent haddonia sp., and fragments of echinoderms. interpretation: sea-grass influenced associations rich in al­ veolinids and miliolids are interpreted as having originated in typical protected lagoonal settings (hottinger, 1983, 1997; geel, 2000; brandano et al., 2009a, b; tomassetti et al., 2016), characterised by occasional short-lived episodes of in­ creased temperature and/or salinity, as observed in tidal pools (causing ‘deformed’ orbitolitid tests – hottinger, 1983). this microfacies is dominant in the stratigraphic unit s2b of the čikola section. the first occurrence is recorded around 70 m and it is present continuously almost until the end of the section (fig. 2). 4.2.8. mft 8 – peloidal-foraminiferal packstone the mft 8 is represented by packstones with dominant peloids (pl. 2, fig. 2) of varying sizes and shapes, irregular to rounded, and foraminiferal tests. fine-grained micritic matrix occasionally shows partial recrystallization. where peloids are sparsely distributed, the micritic matrix and partially recrystallized ma­ trix (sparitic matrix) occur, and where peloids are densely packed, it is hard to distinguish them from the surrounding micritic ma­ trix. dominant skeletal allochems are recrystallized rotaliid foraminifera. porcelaneous foraminifera, which are mostly deformed and bioeroded, and echinoderm fragments are common. skeletal remains are well­sorted and some of the agglutinated conical fora minifera are compacted. interpretation: peloids are common in recent shallow subti­ dal to intertidal environments with moderate to restricted circula­ tion (wilson, 1975; tucker & wright, 1990; flügel, 2010). the abundance of rotaliids and small miliolids indicates probable occurrences of sea-grass or algal covers, and thus eu­ photic conditions, within the shallow marine lagoon or inner ramp settings with possible open marine influence (langer, 1993; geel, 2000; mateu-vicens et al., 2010; pomar et al., 2014). this microfacies occurs in the stratigraphic unit s2b of the čikola section, starting from 120 m (fig. 2). 4.2.9. mft 9 – foraminiferal grainstone mft 9 consists of well-sorted bioclasts of miliolids, alveolinids, rotaliids, and micritized mollusc fragments (pl. 2, fig. 3). occa­ sionally alveolinid tests are oriented, fragmented and abraded. well-sorted grainstones are easily recognizable macroscopically because of the abundance of oriented, up to 3 cm long alveolinid tests. interpretation: mft 9 represents a high-energy environ­ ment, under the influence of waves and currents. alveolinids pre­ ferred algal or sea-grass substrates, although they could have lived on all kinds of substrates. they inhabited shallow-water, protected environments (including protected inner ramp settings) but, also, sand shoals near and below fair-weather wave base (geel, 2000). abraded alveolinid tests and well-sorted grains indicate their probable deposition on inner ramp shoals. generally, porcelaneous foraminifera (miliolids and alveolinids) are abundant in normal marine and, occasionally hypersaline la­ goons (hottinger, 1974; torricelli et al., 2006). this microfacies appears several times along the čikola sec­ tion within stratigraphic unit s2b (fig. 2). 4.2.10. mft 10 – nummulitid packstone the mft 10 is composed of coarse-grained packstones with complete, fragmented and/or abraded (outer whorl missing) lenticular tests of nummulitids (pl. 2, fig. 4). the tests are randomly ori­ ented, and the matrix is composed of fine bioclastic fragments. nummulitid packstones are easily recognizable macroscopically because of the abundance of up to 15 mm long nummulitid tests. interpretation: the deposits identified as mft 10 originat ed in a high-energy environment, where wave and current action was significant. nummulitids are bottom dwellers, and can be found at depths less than 30 m, but are dominant at mesophotic to oligophotic depths (≥30m; hohenegger, 2005). smalland medium-sized lenticular forms lived in various environments within the platform interior, and can form banks (aigner, 1983; geel, 2000). specimens of nummulites larger than 8 mm are frequent in nearshore shoals (torricelli et al., 2006). the prevalence of tests larger than 8 mm suggests that rocks of this microfacies were deposited on shoals. this microfacies appears in stratigraphic unit s2c of the čikola section. 4.2.11. mft 11 – coral-foraminiferal packstone mft 11 is mainly composed of bioclastic-foraminiferal pack­ stones while grainstones with corals (colonial and solitary, scat­ tered in the skeletal matrix; pl. 2, figs. 5, 6) sporadically occur. within the matrix, the diverse fossil association of corals, bryo­ zoans, echinoderms, foraminifera, and coralline red algae is also an abundant one. small lenticular nummulitids, rotaliids (neoro­ talia ex gr. lithotamnica (uhlig)), orthophragmids, and encrust­ ing foraminifera (acervulina linearis hanzawa, miniacina sp., haddonia sp., fabiania cassis (oppenheim) and gyroidi­ nella magna le calvez) are common, whereas alveolinids, miliolids, and planktonic foraminifera are rare. interpretation: coarse-grained matrix with numerous bio­ clasts (in particular, neorotalia spp.) within packstones suggests a higher-energy environment. the co-occurrences of mixotrophs, such as z-corals and lbfs, suggests mesophotic conditions. the encrusting foraminifera are associated with corals (occupying cryptic and semi-cryptic microhabitats; bosellini & papaz­ zoni, 2003) and therefore follow the same environmental re­ quirements as corals. it is known that in the mesophotic zone, corals lived and grew along with red algae (morsilli et al., 2012). in such settings, the high hydrodynamics provided the energy to rework bioclasts and produce skeletal packstones. g eologia c roatica španiček et al.: early eocene evolution of carbonate depositional environments recorded in the čikola canyon ... 17 this microfacies occurs in the last 30 m of the čikola sec­ tion, at the beginning of stratigraphic unit s2c (fig. 2). 4.2.12. mft 12 – rhodolith-nummulitid packstone mft 12 is represented by poorly-sorted fine-grained micritic to coarse-grained packstones (pl. 2, figs. 7, 8). the main characteristics are small rhodoliths and fragments of coralline algae: litho­ thamnion sp., sporolithon sp., mesophyllum sp., lithoporella me­ lobesioides (foslie) and polystrata alba (pfender). fragments of corals or lithoclasts are overgrown by red algae and foraminifera (miniacina sp., solenomeris sp., and acervulina line­ aris hanzawa). other skeletal allochems are ehinoderm frag­ ments, broken lbfs (nummulitids, orthophragmids), and rotaliids. interpretation: rhodoliths dominated by sporolithaceans and melobesioids occur below 60 m depth, and are characteristic of recent carbonate environments below the fair-weather wave base in tropical and subtropical seas (bassi, 2005) in a wide va­ riety of settings, including back-reef, reef-flat and channels, forereef and also in deeper water down to 250 m (bosence, 1983). rhodophyceae live at greater depths than other algae because they can better utilize the blue light that penetrates furthest into the water (lee, 1998) and their occurrence marks the lower limit of the oligophotic zone. coralline algae lithotamnion sp. and mesophyllum sp. are today found between 30 and 80 m depth on the indo-pacific shelves (adey, 1979) and similar facies were interpreted as being deposited in the upper photic zone (rasser, 2000; nebelsick et al., 2013), as suggested by the occurrences of nummulites (hottinger, 1997). small rhodoliths in pack­ stones with fragmented bioclasts suggest some degree of bottom current reworking (bassi, 2005). based on the skeletal composition and textures, deposits of this microfacies probably accumulated in a moderate–high en­ ergy areas within the mesophotic zone, probably in the proximal part of the middle ramp, well above the swb, closer to fwwb. this microfacies occurs only in the last 7 m of the čikola section, at the end of the stratigraphic unit s2c (fig. 2). 4.3. biostratigraphy the s1 unit of the čikola section is characterised by occasional freshwater influences and alternating coal intercalations. the dominant organisms have no biostratigraphic value, so the deter­ mined fossil association does not allow age attribution. in the s2b unit of the čikola section, ranging from 80 to 276 m (fig. 2), several stratigraphically important species of alveolinids (alveolina decastroi, a. cremae, a. multicanalifera, a. levantina), conical agglutinated foraminifera (pseudochrysalidina alva, pfendericonus makarskae and coskinolina liburnica), tremato­ phore miliolids (periloculina dalmatina) as well as orbitolites complanatus have been identified within conical agglutinated foraminiferal packstones (mft 5) and alveolinid-miliolid pack­ stones (mft 7). they indicate the sbz 11–12 and therefore a late ypresian (‘cuisian’) age for this carbonate unit. 5. discussion during the early eocene in the studied area, a succession of car­ bonates around 300 m thick was deposited within shallow-water (neritic) settings, ranging from brackish to protected marine en­ vironments (represented by mft 1 to mft 7) to inner and mid­ dle carbonate ramp environments (represented by mft 8 to mft 12). a palaeoenvironmetal model for the studied succession is provided in fig. 3. the čikola succession is interpreted as having been deposited in subtropical, oligotrophic and euphotic to mix­ ophotic environments based on microfacies characteristics. a total of 12 microfacies types (mft 1 to mft 12) have been distinguished, demonstrating a diverse array of depositional and palaeoenvironmental conditions. they reflect a great diver­ sity of shallow-marine biota, especially lbf as a highly diversi­ fied group with specific environmental preferences (hot­ tinger, 1983, 1997) within f luctuating environmental figure 3. schematic palaeoenvironmetal model of the early eocene čikola carbonate ramp with interpreted facies belts: brackish coastal environments (mft 1–3); protected lagoonal environments (mft 4–7); inner ramp environments (mft 8, 11); inner ramp shoals (mft 9, 10), and middle ramp environments (mft 12). g eo lo gi a c ro at ic a geologia croatica 70/118 conditions. restricted, lagoonal environments with fresh water influence (occurrences of charophyceae along with ostracods and gastropods) are recorded in microfacies units mft 1 to mft 3 (s1 unit in fig. 2). foraminiferal limestones (s2 unit in fig. 2), composed of microfacies mft 4 to mft 12, with miliolids, lbf (including alveolinids and orbitolitids) and agglutinated conical foraminifera, were deposited in the inner ramp settings. differentiation between two sub-settings based on the proportion of particular foraminiferal genera in assemblages was done. the microfacies mft 4 and mft 6 originated under low-energy con­ ditions are characterised by the dominance of miliolids and spo­ radic occurrences of small, unidentified rotaliids. diverse assem­ blages of alveolinids (fusiform to elliptical forms, representatives of a-generation), agglutinated conical foraminifera, larger mili­ olids, orbitolitids and z-corals characterised inner ramp settings. where the influence of wave action was significant, shoals were formed, as indicated by the mft 9 and mft 10. the middle ramp settings were characterised by a high abundance of corallinacean red algae (mft 12) while lbf are present in decreased propor­ tions (fig. 3). the dominance of fragments of lbf and macrofos­ sils indicate the high-energy, well-lit part of the middle ramp. a melobesoid assemblage thrived in mid-latitudes within shallowwater warm–temperate settings (aguirre et al., 2000). fossil shallow-water corallinaceans have been reported from the tethy an areas (bosence, 1983; bassi, 1998, 2005; bassi & nebel­ sick, 2010) and their co-occurrence with lbf indicates some­ what deeper settings. the succession ends with massive mud­ stone beds with thin streaks, normal-graded interlaminae and lenses of silt or very fine-grained sand, representing initial (prethrusting) fine-grained subneritic deposits belonging to the be­ ginning of the promina beds (mrinjek et al., 2012), suggesting a probably tectonically induced ending of foraminiferal lime­ stone sedimentation. deposition in the čikola section was char­ acterised by shallow-marine (neritic) environments showing an aggradational pattern, composed predominantly of inner-ramp deposits, above the fwwb, except for the last 10 metres. fo­ raminiferal limestones were deposited at the beginning of the foreland basin evolution and represent a bedrock of a wedge-top sub-basin filled up by promina beds. lack of biostratigraphic markers in the s1 unit prevented precise age attribution of the oldest palaeogene deposits, (the kozina beds), in the čikola section. in adjacent areas, the palaeogene transgression started in the middle ‘cuisian’ (sbz 11; drobne et al., 1991). the beginning of sedimentation in the studied section is also assumed to be middle ‘cuisian’, based on the fact that identified alveolinids and associated foraminifera from continuously overlying deposits, belong to the sbz 11–12. as mentioned, sbzs 11–12 correspond to the late ypresian (serra-kiel et al., 1998) and during that period an almost 300 m thick succession of carbonates was deposited. such a mas­ sive amount of carbonates testifies to a fine equilibrium having been established between the tectonically induced creation of ac­ commodation space/subsidence and significant carbonate sedi­ ment production, especially as in the čikola section there is no evidence of subsequent drowning in the form of transitional beds and/or flysch deposits, typical for most other areas with palaeo­ gene deposits. as evidenced, the main characteristic of these deposits is the abundant and diverse assemblage of lbf, major carbonate pro­ ducers of the early palaeogene carbonate environments (hot­ tinger, 1997; pearson, 2012). their occurrence in the area was controlled by the palaeolatitudinal position of the north dal­ matian foreland basin during the early palaeogene, at approxi­ mately 38°n (meulenkamp & sissingh, 2000, 2003) (fig. 4) and by the early palaeogene “warm” climate. the long-term global warming, beginning in the late palaeocene and culminat­ ing during the early eocene climatic optimum (eeco – zachos et al., 2001) with tropical sea-surface temperatures of 28 to 32°c (pearson et al., 2007), enabled abundant carbonate production even in the areas which should, according to their pal­ aeolatitudes, be characterised by a more temperate climate. the sea-level fluctuations, along with variations in the configuration of the sedimentary basins and different subsidence rates, also contributed to such sedimentary scenarios (development of dif­ ferentiated environments – from lagoons and shoals to inner– middle ramp settings). comparison with similar deposits from neighbouring re­ gions (figs. 1a and 5) reveals the following: 1) from nw to se of the dinaridic foreland the different ar­ ray of settings (inner to outer ramp environments) within a car­ bonate ramp system have been recorded in the kras region, istria, ravni kotari, island of hvar and pelješac peninsula. an age dis­ crepancy has been noticed concerning the beginning of the ramp conditions. in the nw part, in the kras region (slovenia, 1 on fig. 5), the older part of the succession, the liburnian formation is of maastrictian age (zamagni et al., 2008, 2012; jurkovšek et al., 2016). ramp settings commenced in istria in the ‘iler­ dian’ (2 on fig. 5; drobne, 1977; drobne et al., 2011; ćosović et al., 2004, 2008a), in the northern dalmatia in the middle ‘cuisian’ (3, 4 and 5 on fig. 5; drobne et al., 1991; babić & zupanič, 2016) in the central dalmatia in the early– middle ‘cuisian’ (pelješac and hvar, 6 and 7 on fig. 5; mar­ janac et al., 1998; schweitzer et al., 2007). 2) the thicknesses of palaeogene carbonate ramp system de­ posits vary from only 38 m (at hvar, marjanac et al., 1998) to the maximum of 280 m (benkovac area, drobne et al., 1991). 3) in some areas, including the studied one, the complete ramp system succession was not developed. comparison with neighbouring regions reveals its complete development in istria, whereas in dalmatia (ravni kotari, hvar and pelješac area) only some parts of the entire sequence were documented. figure 4. simplified palaeogeographic reconstruction of the mediterranean realm in the early to middle eocene with marked position of the north dalma­ tian basin. the positions of the continents and ocean basins are adapted from meulenkamp & sissingh (2000, 2003) as presented in höntzsch et al. (2013). g eologia c roatica španiček et al.: early eocene evolution of carbonate depositional environments recorded in the čikola canyon ... 19 4) deposition in the entire north dalmatian area, from the middle ‘cuisian’ onward, was characterised by more or less con­ tinuous shallow-marine environments, except for a narrow trench characterised by deeper-marine environments that developed in the palaeocene and extended westward from montenegro and eastern herzegovina (chorowicz, 1975; marinčić et al., 1976; jelaska et al., 2003; ćosović et al., 2006). 5) the discrepancy in age and physiography of depositional settings probably resulted from diachronous deformation of the progressively evolving orogen (korbar, 2009) during the early to middle eocene. intense tectonic activity might have pre­ vented the full development of ramp settings. therefore, the palaeogene deposits in the outer dinarides may be considered as syn-orogenic deposits connected to the development and the evolution of foreland basin(s) and were deposited in basins control­ led by deformation related to the dinaric orogen (schmid et al., 2008; korbar, 2009). palaeogene deposits were accumulated on the deformed for­ mer adcp, mostly above the regional unconformity (oto ničar, 2007; korbar, 2009; brlek et al., 2014). gently folded adcp deposits were during the palaeogene gradually drowned and covered by a complex network of depositional environments for which the term palaeogene adriatic carbonate platform was proposed (drobne et al., 2009, 2011). however, during most of the palaeogene, a completely different depositional system was formed, because (1) the former area of the mesozoic adcp was only partially covered by palaeogene marine deposits, (2) instead of the previous vast, relatively flat shallow-marine mesozoic adcp, during the palaeogene complex carbonate ramp deposi­ tional systems were formed, and (3) deposition was primarily con­ trolled by compressional synsedimentary tectonics and although carbona te production (represented mostly by lbf) was an impor­ tant factor (as shown in the čikola section example), the prevail­ ing force in modifying the accommodation space was tectonics, while on the adcp, the dominant factor in sedimentation was car bonate production keeping balance with the subsidence (vlahović et al., 2005). therefore to avoid terminological confusion, a specific name for such a complex palaeogene depositional system should be proposed, in order to clearly distinguish it from the underlying adriatic carbonate platform. 6. conclusions in the čikola canyon, northern dalmatia, during the early eo­ cene around 300 m of carbonates were deposited transgressively over the upper cretaceous (campanian) rudist-bearing limestones, representing one of thicker successions of palaeogene car­ bonates in the dinarides. during the early eocene the sedimen­ tation took place along a neritic carbonate ramp depositional system. in the studied section the carbonate succession comprises an older restricted, c. 45 m thick succession of very shallow-ma­ rine kozina beds, and a late ypresian (sbz 11–12) foraminiferal limestones succession deposited within inner to middle ramp en­ vironments. foraminiferal limestones were dominated by larger benthic foraminifera (mostly conical agglutinated foraminifera, larger miliolids and alveolinids), and during the upper ypresian (cca. 2.6 ma) approximately 250 m of shallow-marine carbonates were deposited in relatively stable environments, indicating a bal­ ance between tectonically induced subsidence and carbonate sedimentation. figure 5. schematic correlation of cretaceous to palaeogene carbonate and clastic successions in the area of the dinarides (for location see fig. 1), from nw to se: (1) kras region (modified after drobne & pavšić, 1991; živković & babić, 2003; zamagni et al., 2008); (2) istria (modified after benić, 1991; drobne & pavlovec, 1991; ćosović et al., 2004); (3) korlat–benkovac section (modified after ivanović et al., 1976; drobne et al., 1991); (4) skradin–dubravice section (modified after mamužić, 1975; drobne et al., 1991; marjanac & ćosović, 2000); (5) čikola section (this paper); (6) hvar, podstina section (modified after puškarić, 1997; mar­ janac et al., 1998; pavšič & premec fuček, 2000: schweitzer et al., 2007; korbar et al., 2015), and (7) pelješac, orebić section (modified after marjanac et al., 1998). g eo lo gi a c ro at ic a geologia croatica 70/120 based on lithology, grain types and fossil assemblages (mainly lbf) 12 microfacies types were identified, showing con­ solidation and development of a fully marine regime. microfacies mft 1 to mft 3 are typical of deposits originating within re­ stricted, unstable environments with the influence of fresh water. the inner ramp wackestones to packstones (microfacies mft 4 to mft 11), with abundant and diverse lbf assemblages were deposited under lowto high-energy conditions, i.e. in protected lagoons (mft 5, 6, 7), inner high-energy parts of carbonate ramp (mft 9, 10) and in distal inner ramp settings (mft 11). the mid­ dle ramp environments were recorded by the mft 12, where corallinaceans and lbf co­occurred. from the latest cretaceous to the bartonian in the area of the dinarides several carbonate ramp systems were developed. each ramp system was characterised by its different evolution through­ out its existence, including variable thickness, different ages of initiation and duration of marine conditions, and deposition in different sedimentary environments controlled primarily by syn­ sedimentary tectonics related to the evolving dinaric orogen. acknowledgement the authors are grateful to katica drobne (ljubljana), since this paper benefited greatly from her suggestions regarding al­ veolinids. also, we would like to thank robert košćal for drawings, and željko ištuk for help in thin section preparation. this study was sponsored by the support grant provided by the university of zagreb, and partly supported by the croatian sci­ ence foundation under the project hrzz ip-2014-09-9541. we would especially like to thank reviewers, adrijan košir (lju­ bljana) and tvrtko korbar (zagreb) for their suggestions that significantly improved this work. references adey, w.h. (1979): crustose coralline algae as microenvironmental indicators in the tertiary.– in: gray, j. & boucot, a.j. (eds.): historical biogeography, plate tectonics and the changing environment. oregon state univ. press, corvallis, 459–464. afzal, j., williams, m., leng, m.j., aldridge, r.j. & stephenson, m.h. (2011): evolution of paleocene to early eocene larger benthic foraminifer assem­ blages of the indus basin, pakistan.– lethaia, 44, 299–320. doi: 10.1111/j.1502-3931.2010.00247.x aguirre, j., riding, r. & braga, j.c. (2000): diversity of coralline red algae: origination and extinction patterns from the early cretaceous to the pleistocene.− paleobiology, 26, 651–667. doi: 10.1666/0094-8373(2000)026%3c0651:docr ao%3e2.0.co;2 aigner, t. (1983): event-stratification in nummulite accumulations and in shell beds from the eocene of egypt.– in: einsele, g. & seilacher, a. (eds.): cyclic and event stratification. springer, berlin, 248–262. doi: 10.1007/978-3-64275829-4_19 babić, lj. & zupanič, j. (1983): paleogene clastic formations in northern dalma­ tia.− in: babić, lj. & jelaska, v. (eds.): contributions to sedimentology of some carbonate and clastic units of the coastal dinarides, excursion guidebook. international association of sedimentologists 4th regional meeting, split, 37–61. babić, lj. & zupanič, j. (2007): major events and stages in the sedimentary evolu­ tion of the paleogene promina basin (dinarides, croatia).− natura croatica, 16/4, 215–232. babić, lj. & zupanič, j. (2008): evolution of a river-fed foreland basin fill: the north dalmatian flysch revisited (eocene, outer dinarides).− natura croatica, 17, 357–374. babić, lj. & zupanič, j. (2012): laterally variable development of a basin-wide transgressive unit of the north dalmatian foreland basin (eocene, dinarides, croatia).− geologia croatica, 65, 1–27. doi: 10.4154/gc.2012.01 babić, lj. & zupanič, j. (2016): the youngest stage in the evolution of the dinaric carbonate platform: the upper nummulitic limestones in the north dalmatian foreland, middle eocene, croatia.− natura croatica, 25/1, 55–71. bassi, d. (1998): coralline algal facies and their palaeoenvironments in the late eocene of northern italy (calcare di nago, trento).− facies, 39, 179–202. doi: 10.1007/ bf02537016 bassi, d. (2005): larger foraminiferal and coralline algal facies in an upper eocene storm influenced, shallow water carbonate platform (colli berici, north-eastern italy).− palaeogeography, palaeoclimatology, palaeoecology, 226, 17–35. doi: 10.1016/j.palaeo.2005.05.002 bassi, d. & nebelsick, j.h. (2010): components, facies and ramps: redefining up­ per oligocene shallow water carbonates using coralline red algae and larger fo­ raminifera (venetian area, northeast italy).− palaeogeography, palaeoclimatology, palaeoecology, 295, 258–280. doi: 10.1016/j.palaeo.2010.06.003 benić, j. (1991): the age of the istria flysch deposits based on calcareous nannofos­ sils.− in: drobne, k. & pavlovec, r. (eds.): introduction to the paleogene sw slovenia and istria. igcp project 286 ˝early paleogene benthos˝, 2nd meet­ ing postojna, paleontološki inštitut i. rakovca zrc sazu, ljubljana, 25. bosellini, f.r. & papazzoni, c.a. (2003): palaeoecological significance of coral− encrusting foraminiferan associations: a case-study from the upper eocene of northern italy.– acta palaeontologica polonica, 48/2, 279–292. bosence, d.w.j. (1983): coralline algal reef frameworks: cenozoic carbonates.– jour­ nal of the geological society, 140/3, 365–376. doi: 10.1144/gsjgs.140.3.0365 bosence, d.w.j. (2005): a genetic classification of carbonate platforms based on their basinal and tectonic settings in the cenozoic.− sedimentary geology, 175, 49–72. doi: 10.1016/j.sedgeo.2004.12.030 boudagher-fadel, m.k. (2008): evolution and geological significance of larger benthic foraminifera.− development in palaeontology and stratigraphy, 21, else­ vier, 540 p. brandano, m., frezza, v., tomassetti, l. & cuffaro, m. (2009a): heterozoan carbonates in oligotrophic tropical waters: the attard member of the low­ er coralline limestone formation (upper oligocene, malta).− palaeogeography, palaeoclimatology, palaeoecology, 274/1, 54–63. doi: 10.1016/j.palaeo.2008.12.018 brandano, m., frezza, v., tomassetti, l., pedley, m. & matteucci, r. (2009b): facies analysis and palaeoenvironmental interpretation of the late oli­ gocene attard member (lower coralline limestone formation), malta.− sedi­ mentology, 56, 1138–1158. doi: 10.1111/j.1365-3091.2008.01023.x brlek, m., korbar, t., košir, a., glumac, b., grizelj, a. & otoničar, b. (2014): discontinuity surfaces in upper cretaceous to paleogene carbonates of central dalmatia, croatia: glossifungites ichnofacies, biogenic calcretes, and strati­ graphic implications.− facies, 60/2, 467–487. doi: 10.1007/s10347-013-0378-9 burchette, t.p. & wright, v.p. (1992): carbonate ramp depositional systems.− sedimentary geology, 79, 3–57. doi: 10.1016/0037-0738(92)90003-a buxton, m.w.n. & pedley, h.m. (1989): a standardized model for tethyan terti­ ary carbonate ramps.− journal of the geological society (london), 146, 746–748. chorowicz, j. (1975): le devenir de la zone de budva vers le nord-ouest de la you­ goslavie.− bulletin de la societe geologique de france, 7/17, 699–709. doi: 10.2113/gssgfbull.s7-xvii.5.699 ćosović, v., drobne, k. & moro, a. (2004): paleoenvironmental model for eocene foraminiferal limestones of the adriatic carbonateplatform (istrian penin­ sula).– facies, 50, 61–75. ćosović, v., premec fuček, v., gušić, i., jelaska, v. & moro, a. (2006): the age of the tilovica breccias in central dalmatia, croatia.− micropaleonto-micropaleonto­ logy, 52, 281–286. doi: 10.2113/gsmicropal.52.3.281 ćosović, v., marjanac, t., drobne, k. & moro, a. (2008a): outer dinarides: eastern adriatic coast. paleogene and neogene.− in: mccann, t. (ed.): the ge­ ology of central europe, volume 2: mesozoic and cenozoic. the geological so­ ciety london, london, 1031–1139. ćosović, v., drobne, k., ogorelec, b., moro, a., koić, m., šoštarko, i., tarlao, a. & tunis, g. (2008b): decastronema barattoloi (de castro), characteristic fossil of the paleocene and the eocene peritidal sediments from the adriatic carbonate platform.− geologia croatica, 61, 321–332. doi: 10.4154/ gc.2008.24 drobne, k. (1974): les grandes miliolidées des couches paléocènes de yougoslavie du nord-ouest.− razprave iv. razr. sazu, 17, 129−184. drobne, k. (1977): alvéolines paléogènes de la slovénie et de l’istrie.– schweiz. paläont. abhandl., 99, 1–132. drobne, k. (1985): periloculina dalmatina a new trematophorid miliolid foraminifera from the cuisian of yugoslavia.– razprave 4. razr. sazu, 26, 159–176. drobne, k. & pavlovec, r. (1991): paleocene and eocene beds in slovenia and istria.− in: drobne, k. & pavlovec, r. (eds.): introduction to the paleogene sw slovenia and istria. igcp project 286 “early paleogene benthos”, 2nd meet­ ing postojna, paleontološki inštitut i. rakovca zrc sazu, ljubljana, 7–18. drobne, k. & pavšič, j. (1991): clastic carbonate deposits in sw slovenia and is­ tria (podsabotin beds – paleocene; flysch – paleocene, eocene; kožbana beds – paleocene; međana beds – eocene).− in: drobne, k. & pavlovec, r. (eds.): introduction to the paleogene sw slovenia and istria. igcp project 286 ˝early paleogene benthos˝, 2nd meeting postojna, paleontološki inštitut i. rakovca zrc sazu, ljubljana, 19–21. drobne, k., vlahović, i., trutin, m., pavlovec, r., ćosović, v., babac, d., cimerman, f., lučić, d. & pavšič, j. (1991): excursion b – ravni ko­ tari, paleogene.− in: vlahović, i. & velić, i. (eds): some aspects of the g eologia c roatica španiček et al.: early eocene evolution of carbonate depositional environments recorded in the čikola canyon ... 21 shallow-water sedimentation on the adriatic carbonate platform (permian to eocene), 2nd international symposium on the adriatic carbonate platform, ex­ cursion guidebook. institute of geology, zagreb, 53–70. drobne, k., ogorelec, b., pavšič, j. & pavlovec, r. (2009): paleocene and eocene in sw slovenia.− in: pleničar, m., ogorelec, b. & novak, m. (eds.): geology of slovenia. geološki zavod slovenije, 311–372. drobne, k., ćosović, v., moro, a. & bucković, d. (2011): the role of the palaeogene adriatic carbonate platform in the spatial distribution of alveolinids.− turkish journal of earth sciences, 20, 721–751. dunham, r.j. (1962): classification of carbonate rocks according to depositional tex­ ture. in: ham, w.e. (ed.): classification of carbonate rocks. american associa­ tion of petroleum geologists memoir, 1, 108–121. embry, a.f., iii & klovan, j.s. (1971): a late devonian reef tract on northeastern banks island.− n.w.t. bulletin of canadian petroleum geology, 4, 730–781. flügel, e. (2010): microfacies of carbonate rocks.− springer-verlag, berlin, 976 p. doi: 10.1007/978-3-642-03796-2 geel, t. (2000): recognition of stratigraphic sequences in carbonate platform and slope deposits: empirical models based on microfacies analysis of paleogene deposits in southeastern spain.− palaeogeography palaeoclimatology palaeoecology, 155, 211–238. doi: 10.1016/s0031-0182(99)00117-0 hallock, p. (1999): symbiont-bearing foraminifera.− in: sen gupta, b.k. (ed.): modern foraminifera. kluwer academic publishers, dordrecht, 123–139. doi: 10.1007/0-306-48104-9_8 hohenegger, j. (2004): depth biocoenoclines and environmental considerations of western pacific larger foraminifera.− the journal of foraminifeal research, 34, 9–33. hohenegger, j. (2005): estimation of environmental paleogradient values based on presence/absence data: a case study using benthic foraminifera for paleodepth es­ timation.− palaeogeography, palaeoclimatology, palaeoecology, 217, 115–130. doi: 10.1016/j.palaeo.2004.11.020 höntzsch, s., scheibner, c., brock, j.p. & kuss, j. (2013): circum-tethyan carbonate platform evolution during the palaeogene: the prebetic platform as a test for climatically controlled facies shifts.− turkish journal of earth sciences, 22, 891–918. doi:10.3906/yer-1207-8 hottinger, l. (1960): recherches sur les alvéolines paléocènes et éocènes.− schwei-schwei­ zerische paläontologische abhandlungen, 75–76, 1–236. hottinger, l. (1974): alveolinids, cretaceous-tertiary larger foraminifera.− esso production research european laboratories, 84 p. hottinger, l. (1983): processes determining the distribution of larger foraminifera in space and time.− utrecht micropaleontol. bull., 30, 239–253. hottinger, l. (1997): shallow benthic foraminiferal assemblages as signals for depth of their deposition and their limitations.− bulletin de la société géologique de france, 168, 591–505. hottinger, l. & drobne, k. (1980): early tertiary conical imperforate foramini­ fera.− razprave iv. razreda sazu, 22, 186–276. ivanović, a., sakač, k., marković, s., sokač, b., šušnjar, m., nikler, l. & šušnjara, a. (1973): osnovna geološka karta sfrj 1:100000, list obro­ vac [basic geological map of sfry 1:100000, obrovac sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. ivanović, a., sakač, k., sokač, b., vrsalović-carević, i. & zupanič, j. (1976): osnovna geološka karta sfrj 1:100000. tumač za list obrovac [basic geological map of sfry 1:100000, geology of the obrovac sheet – in croatian, english abstr.].– geološki zavod, zagreb, savezni geološki zavod, beograd, 61 p. ivanović, a., sikirica, v., marković, s. & sakač, k. (1977): osnovna geološka karta sfrj 1:100000, list drniš [basic geological map of sfry 1:100000, drniš sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. jelaska, v., benček, ð., cvetko tešović b., ćosović, v., gušić, i., ištuk, ž. & matičec, d. (2003): platform dynamics during the late creta­ ceous and early palaeogene – external dinarides, dalmatia.− in: vlahović, i. & tišljar, j. (eds.): evolution of depositional environments from the palaeo­ zoic to the quaternary in the karst dinarides and the panonnian basin, 22nd ias meeting of sedimentology − opatija 2003, field trip guidebook. croatian geo­ logical survey, 101–107. jurkovšek, b., biolchi, s., furlani, s.,kolar-jurkovšek, t., zini, l., jež, j., tunis, g., bavec, m. & cucchi, f. (2016): geology of the classical karst region (sw slovenia–ne italy).− journal of maps, 12/s1, 352–362, doi: 10.1080/17445647.2016.1215941 korbar, t. (2009): orogenic evolution of the external dinarides in the ne adriatic region: a model constrained by tectonostratigraphy of upper cretaceous to paleo­ gene carbonates.– earth-sci. reviews, 96/4, 296–312. doi: 10.1016/j.earsci­ rev.2009.07.004 korbar, t., montanari, a., premec fućek, v., fuček, l., coccioni, r., mcdonald, i., claeys, p., schulz, t. & koeberl, c. (2015): potential cretaceous–paleogene boundary tsunami deposit in the intra-tethyan adriatic car­ bonate platform section of hvar (croatia).− geological society of america bul­ letin, 127/11–12, 1666–1680. doi: 10.1130/b31084.1 košir, a. (2004): microcodium revisited: root calcification products of terrestrial plants on carbonate-rich substrates.– journal of sedimentary research, 74/6, 845–857. doi: 10.1306/040404740845 langer, m.r. (1993): epiphytic foraminifera.− marine micropaleontology, 20, 235–265. doi: 10.1016/0377-8398(93)90035-v lee, j.j. (1998): living sands: larger foraminifera and their endosymbiotic algae.− symbiosis, 25, 71–100. mamužić, p. (1971): osnovna geološka karta sfrj 1:100000, list šibenik [basic ge­ ological map of sfry 1:100000, šibenik sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. mamužić, p. (1975): osnovna geološka karta sfrj 1:100000. tumač za list šibenik k33-8 [basic geological map of sfry 1:100000, geology of the šibenik sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd, 37 p. marinčić, s., korolija, b. & majcen, ž. (1976): osnovna geološka karta sfrj 1:100000, list omiš [basic geological map of sfry, omiš sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. marjanac, t. & ćosović, v. (2000): tertiary depositional history of eastern adri­ atic realm.– vijesti hrvatskoga geološkog društva, 37/2, 93–103. marjanac, t., babac, d., benić, j., ćosović, v., drobne, k., marjanac, lj., pavlovec, r. & velimirović, z. (1998): eocene carbonate sediments and sea-level changes on the se part of adriatic carbonate platform (island of hvar and pelješac peninsula, croatia).− in: hottinger, l. & drobne, k. (eds.): paleogene shallow benthos of the tethys. dela, slov. akad. znan. umetn. (sazu), 34, 243–254. mateu-vicens, g., box, a., deudero, s. & rodríguez, b. (2010): comparative analysis of epiphytic foraminifera in sediments colonized by seagrass posi­ donia oceanica and invasive macroalgae caulerpa spp.− the journal of fo­ raminifeal research, 40, 134–147. doi: 10.2113/gsjfr.40.2.134 meulenkamp, j.e. & sissingh, w. (2000): early to middle ypresian, late lutetian, late rupelian, early burdigalian, early langhian, late tortonian, piacenzian/gela­ sian.– in: dercourt, j. & gaetani, m., et al. (eds.): atlas peri-tethys, palaeogeographical maps. ccgm/cgmw, paris, 17–23. meulenkamp, j.e. & sissingh, w. (2003): tertiary palaeogeography and tectonostratigraphic evolution of the northern and southern peri-tethys platforms and the intermediate domains of the african-eurasian convergent plate boundary zone.– palaeogeography, palaeoclimatology, palaeoecology 196, 209– 228. doi: 10.1016/s0031-0182(03)00319-5 morsilli, m., bosellini, f.r., pomar, l., hallock, p., aurell, m. & pa­ pazzoni, c.a. (2012): mesophotic coral buildups in a prodelta setting (late eocene, southern pyrenees, spain): a mixed carbonate–siliciclastic system.– sedimentology, 59/3, 766–794. doi: 10.1111/j.1365-3091.2011.01275.x mrinjek, e., nemec, w., pecinger, v., mikša, g., vlahović, i., ćosović, v., velić, i., bergant, s. & matičec, d. (2012): the eocene–oligocene promina beds of the dinaric foreland basin in northern dalmatia.− in: gawlick, h.j. & lein, r. (eds.): 29th ias meeting of sedimentology − schladming 2012, field trip guides. geoaustria, wien, 409–451. nebelsick, j.h., bassi, d. & lempp, j. (2013): tracking paleoenvironmental changes in coralline algal-dominated carbonates of the lower oligocene calcareniti di castelgomberto formation (monti berici, italy).− facies, 59/1, 133–148. doi: 10.1007/s10347-012-0349-6 otoničar, b. (2007): upper cretaceous to paleogene forebulge unconformity asso­ ciated with foreland basin evolution (kras, matarsko podolje and istria; sw slov­ enia and nw croatia).– acta carsologica, 36/1, 101–120. pavšič, j. & premec fuček, v. (2000): calcareous nannoplankton and planktonic foraminiferal zones during the middle and upper eocene of the ̋ transitional beds˝ of the adriatic platform.– annali di museo civico di storia naturali ferrara, 3, 22–23. pearson, p.n. (2012): oxygen isotopes in foraminifera: overview and historical re­ view.– in: ivany, l.c. & huber, b.t. (eds.): reconstructing earth’s deep-time climate – the state of the art in 2012, paleontological society short course. the paleontological society papers, 18, 1–38. pearson, p.n., van dongen, b.e., nicholas, c.j., pancost, r.d., schouten, s., singano, j.m. & wade, b.s. (2007): stable warm tropical climate through the eocene epoch.− geology, 35, 211–214. doi: 10.1130/ g23175a.1 pomar, l. (2001): types of carbonate platforms: a genetic approach.− basin research, 13, 313–334. doi: 10.1046/j.0950-091x.2001.00152.x pomar, l., mateu-vicens, g., morsilli, m. & brandano, m. (2014): carbonate ramp evolution during the late oligocene (chattian), salento pennin­ sula, southern italy.− palaeogeography, palaeoclimatology, palaeoecology, 404, 109–132. puškarić, s. (1987): calcareous nannoplankton from clastic sediments of the island of hvar.– radovi jugoslavenske akademije znanosti i umjetnosti, 22/431, 7–16. g eo lo gi a c ro at ic a geologia croatica 70/122 rasser, m.w. (2000): coralline red algal limestones of the late eocene alpine fore­ land basin in upper austria: component analysis, facies and paleoecology.− facies, 42, 59–92. doi: 10.1007/bf02562567 romero, j., caus, e. & rosell, j. (2002): a model for the palaeoenvironmental distribution of larger foraminifera based on late middle eocene deposits on the margin of the south pyrenean basin (ne spain).− palaeogeography, palaeoclima­ tology, palaeoecology, 179, 43–56. doi: 10.1016/s0031-0182(01)00406-0 schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpinecarpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss journal of geosciences, 101, 139–183. doi: 10.1007/s00015-008-1247-3 schubert, r.j. (1904): das verbreitungsgebiet der prominaschichten im kartenblat­ te novigrad benkovac (norddalmatien).– jahrb. geol. reichsanst., 54, 461–510. schubert, r.j. (1908): geologische spezialkarte der österreichisch-ungarischen monarchie, 1:75000. novigrad und benkovac.− geologische reichsanstalt, wien. schweitzer, c.e., shirk, a.m., ćosović, v., okan, y., feldmann, r.m. & hoşgör, i. (2007): new species of harpactocarcinus from the tethyan eo­ cene and their paleoecological setting.– j. paleont., 81, 1091–1100. doi: 10.1666/ pleo05-155.1 serra-kiel, j., hottinger, l., caus, e., drobne, k., ferràndez, c., jauhri, a.k., less, g., pavlovec, r., pignatti, j., samsó, j.m., schaub, h., sirel, e., strougo, a., tambareau, y., tosquella, j. & zakrevskaya, e. (1998): larger foraminiferal biostratigraphy of the tethy­ an paleocene and eocene.− bulletin de la société géologique de france, 169, 281–299. tomassetti, l., benedetti, a. & brandano, m. (2016): middle eocene seagrass facies from apennine carbonate platforms (italy).− sedimentary geology, 335, 136–149. doi: 10.1016/j.sedgeo.2016.02.002 torricelli, s., knezaurek, g. & biffi, u. (2006): sequence biostratigraphy and paleoenvironmental reconstruction in the early eocene figols group of the tremp–graus basin (south-central pyrenees, spain).− palaeogeography, palaeo­ climatology, palaeoecology, 232, 1–35. tucker, m.e. & wright, v.p. (1990): carbonate sedimentology.– blackwell, ox­ ford, 496 p. doi: 10.1002/9781444314175 vecchio, e. & hottinger, l. (2007): agglutinated conical foraminifera from the lower–middle eocene of the trentinara formation (southern italy).− facies, 53, 509–533. doi: 10.1007/s10347-007-0112-6. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: paleogeography, main events and depositional dyna mics.− palaeogeography, palaeoclimatology, palaeoecology, 220, 333–360. doi: 10.1016/j.palaeo.2005.01.011 vlahović, i. & velić, i. (2009): liburnijske naslage, foraminiferski vapnenci i prijelazne naslage (?gornji paleocen, donji i srednji eocen –?pc, e1,2) [liburnian de­ posits, foraminiferal limestones and transitional beds (?upper paleocene, low­ er and middle eocene –?pc, e1,2 – in croatian].− in: velić, i. & vlahović, i. (eds.): tumač geološke karte republike hrvatske 1:300000 [explanatory notes of basic geological map of croatia 1:300000 – in croatian]. hrvatski geološki institut, zagreb, 76−77. wilson, j.l. (1975): carbonate facies in geologic history.− springer-verlag, new york, 471 p. doi: 10.1007/978-1-4612-6383-8 zachos, j., pagani, m., sloan, l., thomas, e. & billups, k. (2001): trends, rhythms, and aberrations in global climate 65 ma to present.− science, 292, 686–693. doi: 10.1126/science.1059412 zamagni, j., mutti, m., ballato, p. & košir, a. (2012): the paleocene–eocene thermal maximum (petm) in shallow-marine successions of the adriatic carbonate platform (sw slovenia).− geological society of america bulletin, 124/7–8, 1071–1086. zamagni, j., mutti, m. & košir, a. (2008): evolution of shallow benthic com­ munities during the late paleocene-earliest eocene transition in the northern tethys (sw slovenia).− facies, 54, 25–43. doi: 10.1007/s10347-007-0123-3 živković, s. & babić, lj. (2003): paleoceanographic implications of smaller ben­ thic and planktonic foraminifera from the eocene pazin basin (coastal dinarides, croatia).– facies, 49, 49–60. plate 1 photomicrographs of the lower eocene limestones microfacies types of the studied čikola section: 1) microcodium sp. in non­fossiliferous mudstone to wackestone (mft 1), sample č1.8; 2) charophyceae in ostracod mudstone to wackestone (mft 2), sample č1.21; 3) compressed gastropod shells (on the left) and fragments of gastropod shells and charophyceae (on the right) in dolomitized gastropod wackestone to pack­ stone (mft 3), sample č1.26; 4) unidentified small miliolid and discorbids in bioturbated miliolid mudstone to wackestone (mft 4), sample č1.65; 5) conical agglutinated foraminiferal packstone (mft showing periloculina dalmatina drobne, unidentified small miliolids and agglutinated conical foraminifera, sample č1.174; 6) coskinolina liburnica (stache) and pseudochrysalidina sp. in conical agglutinated foraminiferal packstone (mft 5), sample č1.239; 7) miliolid wackestone to packstone characterised by the abundance of small miliolids, spirolina sp. and simple conical agglutinated foraminifera, cribrobulimina sp. (center), sample č1.63; 8) alveolinid­miliolid packstone (mft 7) showing a fragment of orbitolitid test with the additional perpendicular disk in association with small miliolids and cribrobulimina sp., sample č1.246. g eologia c roatica španiček et al.: early eocene evolution of carbonate depositional environments recorded in the čikola canyon ... 23 g eo lo gi a c ro at ic a geologia croatica 70/124 plate 2 photomicrographs of the lower eocene limestones microfacies types in the studied čikola section: 1) alveolina cremae checchia­rispoli in alveolinid­miliolid packstone (mft 7), sample č1.232; 2) peloidal­foraminiferal packstone (mft 8) defined by peloids, unidentified rotaliid foraminifera and fragmented alveolinids, sample č1.186; 3) foraminiferal grainstone (mft 9) showing association of miliolids, alveolinids and micritized echinoid radiolas, sample č1.158; 4) unidentified nummulites in nummulitid packstone (mft 10), sample č1.275; 5) coral­foraminiferal packstone (mft 11) showing a detail of a coral, sample č1.298, 6) fragments of echinoids, coralline algae, alveolinids and unidentified small rotaliids in coral­foraminiferal packstone (mft 11), sample č1.296; 7) detail of encrusting foraminifera solenomeris sp. (on the left) in rhodolith­foraminiferal packstone (mft 12) with fragments of echinoids, corals, orthophragmi­ nids and planktonic foraminifera (right from the centre), sample č1.302; 8) rhodolith­foraminiferal packstone showing fragmented foraminifera and lithothamnion sp. crusts, sample č1.301. g eologia c roatica španiček et al.: early eocene evolution of carbonate depositional environments recorded in the čikola canyon ... 25 g eo lo gi a c ro at ic a geologia croatica 70/126 2016 | 69/2 | 201–204 | 4 figs. | www.geologia-croatica journal of the croatian geological survey and the croatian geological society article history: manuscript received september 02, 2015 revised manuscript accepted march 03, 2016 available online may 16, 2016 keywords: central paratethys, medvednica mt., miocene, badenian, acanthuridae first record of acanthuridae (surgeonfish) from the miocene deposits of the medvednica mt. kristina tripalo1, sanja japundžić2, jasenka sremac3 and marija bošnjak2 1 šestinski vrh 43a, zagreb, croatia; (ktripalo@gmail.com) 2 croatian natural history museum, department of geology and paleontology, demetrova 1, zagreb, croatia; (sanja.japundzic@hpm.hr, marija.bosnjak@hpm.hr) 3 university of zagreb, faculty of science, department of geology, division of geology and paleontology, horvatovac 102a, zagreb, croatia; (corresponding author: jsremac@geol.pmf.hr) doi: 10.4154/gc.2016.15 abstract middle miocene deposits at the dubravica locality in sw medvednica mt. (n croatia) contain various marine fossils, including one tooth of the surgeonfish (acanthuridae). this is the first such record in croatia and the second in the wider region, besides the vienna basin. the appearance of surgeonfishes in the paratethys coincides with the miocene thermal maximum. their distribution was probably controlled by available reef habitat and their palaeobiogeography and migration routes are yet to be studied. 1. introduction northern and north-eastern croatia during the miocene epoch were covered by the paratethys sea (fig. 1). abundant and diverse marine fossils can be found in sedimentary rocks of this age. med vednica mt. acted as an island near the sw coast of the paratethys, and miocene shelf deposits are exposed today in the form of a belt around the mountain core. middle miocene marine environments of medvednica mt. were divided into the ‘’dolje’’ development in the south-western part of medvednica mt., the ‘’čučerje’’ development in the central part of medvednica mt., and the ‘’zelina’’ development in the south-eastern part of medvednica mt., each characterized by different fossil assemblages (kochansky, 1944). miocene deposits of the south-western part of medvednica mt., considered to be a part of the ‘’dolje’’ development, have been studied by many authors (e.g. kochansky, 1944; kochansky-devidé, 1957; šikić et al., 1977, 1979; kochansky-devidé & bajraktarević, 1981; vrsaljko et al., 2006, 2007; bošnjak et al., 2014). the dubravica locality (fig. 1), records the first occurrence of fossil acanthuridae in croatia, and is situated on the southwestern slopes of medvednica mt. the surgeonfish tooth was dis covered during recent field work (bošnjak et al., 2014; tripalo et al., 2015). 2. geological setting the investigated area is a part of the miocene deposits belt surrounding medvednica mt., and is situated on its south-western slopes (fig. 1). geological and palaeontological features of this area were summarized in publications following the basic geological mapping, by šikić et al. (1977, 1979), and later by šikić (edit.) (1995). during the miocene, the whole area palaeogeographically belonged to the south-western margins of the central paratethys (fig. 1), and geotectonically to the pannonian basin system (pavelić, 2002). an approximately 16 metre high subvertical outcrop, with sedimentary rocks of ca. 11.5 m in thickness, is exposed at the dubravica locality near the path leading to the veternica cave (fig. 2). triassic dolomites in the base are transgressively overlain with dolomitic breccias, which gradually pass into brecciasconglomerates, and are later replaced with floatstones containing figure 1. location of the dubravica locality and palaeogeographic map of central paratethys (after vrsaljko et al., 2006; from bošnjak et al., 2014). g eo lo gi a c ro at ic a geologia croatica 69/2202 pikija in velić & vlahović, 2009; bajraktarević & kochansky-devidé, 1981; vrsaljko et al., 2006, 2007), suggest that the deposits are of middle miocene (upper badenian) age (bošnjak et al., 2014; bošnjak et al., 2015). 3. material and methods selected samples from the three layers of the dubravica locality (fig. 2) were analyzed following wet sieving. samples were prepared in the wet laboratory, at the faculty of science in zagreb, department of geology, division of geology and palaeontology. soft marls were crushed, then soaked in the water with hydrogen peroxide. after twenty-four hours, samples were flushed through the 0.5, 0.2 and 0.125 mm sieves. special attention was given to those with mesh size of 0.2 and 0.125 mm as these were the fractions where fossil fish teeth were discovered. the surgeonfish tooth was found on the 0.2 mm sieve. 4. results fish remains are common fossils in the neogene deposits of central paratethys. fish teeth are particularly common and well preserved reflecting their solid construction. from the badenian deposits of medvednica mt., fossil teeth of chrysophrys sp., odontaspis sp., lamna sp., and mylobatis sp. have been observed to date (kochansky, 1944; šikić et al., 1979). among other microfossils from the investigated dubravica locality, one tooth from the acanthuridae was also found. class: actinopterygii (klein, 1885) order: perciformes (bleeker, 1859) family: acanthuridae bonaparte, 1832 the acanthuridae includes fishes whose common name (surgeonfishes) derives from the presence of a scalpel-like modified scale on the caudal peduncle (winterbottom, 1993), which may be used in interand intra-specific aggressive behaviour (randall, 2001). today, acanthurids all live in tropical and subtropical seas, and are one of the dominant groups of fish on the coral reefs (purcell & bellwood, 1993 and references therein; sorenson et al., 2013; ludt et al., 2015). their modern geographic distribution is similar to other reef fish families and largely reflects neogene biogeographic influences (pellissier et al., 2014). surgeonfishes are primarily herbivores, but consume a relatively wide variety of dietary resources, including planktonic animal matter, organic detritus and invertebrates (sorenson et al., 2013). dentition can vary dramatically within and across genera, and it is strongly related to diet (tyler, 1970) (fig. 3). bivalve moulds and dispersed dolomitic cobbles. a horizon composed of dark grey marl, ca. 2.5 m thick, overlies this layer. it contains molluscs, solitary corals, bryozoans, echinoids and trace fossils. the upper part of the column is characterized by a lightgrey marl, ca. 3 m thick, with molluscs. an intercalation of yellowish sandstone with bivalves and gastropods, ca. 0.5 m thick, occurs within this horizon (fig. 2). in the vicinity of the sampled section, ca. 15 m towards the south, marls are laterally replaced with a coralgal reef buildup („lithothamnium limestone“, sensu kochansky, 1944) of con temporary age. the visible part of this buildup is ca. 10 m wide and ca. 5 m high. marls and sandstones from the dubravica locality contain a rich microfossil assemblage present in all of the three analyzed layers (fig. 2), containing juvenile and fragmented molluscs, foraminifera, ostracods, bryozoans, fish teeth and bones, echinoid spines and sponge spicules. in the light grey marl layer (fig. 2), a fish tooth from the acanthuridae family was discovered (bošnjak et al., 2014; tripalo et al., 2015). the collected fossil as semblages when compared with the available published data (e.g. kochansky, 1944; šikić et al., 1977, 1979; šikić, 1995; figure 2. schematic geological column of the dubravica locality (after bošnjak et al., 2014). numbers 1, 2, and 3 mark investigated layers; 1: dark grey marl, 2: light grey marl, 3: intercalation of yellow sandstone. location of the horizon with the surgeonfish tooth is marked with arrow. figure 3. examples of teeth of the acanthuridae family: naso – fixed teeth, mostly conical but slightly distally compressed, with denticulations variously small, minute or absent; ctenochaetus – numerous, elongated, moveable teeth well denticulated on one side only; other genera (paracanthurus, zebrasoma and acanthurus) – fixed teeth, compressed with well developed denticulations (after tyler, 1970). g eologia c roatica tripalo et al.: first record of acanthuridae (surgeonfish) from the miocene deposits of the medvednica mt. 203 acanthuridae gen. et sp. indet. material: one partially preserved tooth with accreted sediment (fig. 4) as shown on fig. 4, the exposed part of the small incisiform tooth is almost black in color. dimension of the tooth (in mm) are: 1.95 height, 1.13 width. the tooth has a multidenticulate structure typical of the majority of acanthurids. one apical denticulation, two denticulations on the right and three on the left side of the tooth are visible. denticulations on both sides increase in size towards the base of the teeth. the investigated tooth is slightly curved inward. its surface is almost smooth on both the labial and lingual side (fig. 4). considering the partial tooth preservation, and range of genera with this configuration, determination at the generic level was not possible. 5. discussion fossil acanthuridae or surgeonfishes are among the best studied fossil percomorph fishes. the rich fossil record indicates that acanthurids reached a significant diversity by the middle eocene (sorenson et al., 2013). abundant and diverse surgeonfishes from the monte bolca locality, at least 14 extinct genera and 16 species, were studied by several authors (blot & tyler, 1990; sorbini & tyler, 1998a, b; tyler, 1999, 2005a, b; tyler & bannikov, 2000). the monte bolca fish assemblage represents the oldest known fauna that may be defined as a coral reef fish assemblage (bellwood, 1996) and is a key fossil deposit at the birth of modern coral reefs (bellwood et al., 2014). several genera share the multidenticulate tooth form at this time (bellwood et al., 2014) suggesting that they may have been feeding on short algal turf (purcell & bellwood, 1993). some fossil taxa of the acanthuridae are known from the oligocene deposits (tyler, 2000; tyler & sorbini, 1998; tyler & micklich, 2011). previously miocene surgeonfishes have only been reported from sulawesi (tyler, 1997) and from the miocene of the vienna basin (meyer, 1842; schultz, 2003). austrian acanthurid fish teeth were described as acanthurus haueri (meyer, 1842). they are of similar size as the specimen from dubravica, but differ from it in shape. as we are lacking other parts of the skeleton, we can only speculate whether this is a different species, but it is also possible that the tooth belongs to the same species, but had a different position within the jaws (schultz & bellwood, 2004). miocene reefs and reef-like structures in paratethys which were suitable habitats for acanthurids were predominantly composed of coralline algae: lithothamnion valens, phymatoliton calcareum and mesophyllum roveretoi (basso et al., 2008), sometimes in association with bryozoans and, sporadically, corals (vrsaljko et al., 2006). interestingly only one other herbivorous reef fish has been recorded from this region, the parrotfish calotomus from the badenian of austria (bellwood & schultz, 1991). findings of acanthurid teeth in the paratethys realm coincide with the miocene thermal maximum. we can discuss why are these finds so scarce; the small size of acanthurid teeth and their rather bizarre shape may be the reason that palaeontologists do not register or recognize them in the sieved material. the croatian surgeonfish record opens discussion of the possible ancestral populations and fish migration routes, but such study requires reexamination of other contemporary rocks along the paratethys reef formations and the possible discovery of more surgeonfish remains. 6. conclusions a small fish tooth from the dubravica locality in the south-western part of medvednica mt. represents the first record of surgeonfishes (acanthuridae) in croatia. in the nearby area, similar teeth from miocene deposits of the vienna basin have been referred to the type acanthurus haueri (meyer, 1842; schultz, 2003). the tooth from the dubravica locality differs from the austrian samples in shape, but is of similar size. it may belong to another species, or to the same species, but from a different position within the jaw. the appearance of acanthurids in the paratethys corresponds with the miocene thermal maximum, and it opens discussion about the ancestral populations and possible biogeographic extent of the acanthuridae across paratethys. palaeoecologically it was controlled by distribution of suitable benthic habitats, in this case coralgal or coralgal-bryozoan reef buildups. acknowledgment the authors thank prof. david bellwood from the college of marine and environmental sciences, james cook university, townsville, australia, for help in fish tooth analyzing techniques and discussion support. we wish to thank the division of geology and palaeontology, department of geology, faculty of science, university of zagreb, and the croatian natural history museum, for their support. we are grateful to both reviewers for their useful comments and suggestions. references basso, d., vrsaljko, d. & grgasović, t. (2008): the coralline flora of a miocene maërl: the croatian ”litavac”.– geologia croatica, 61/2–3, 333–340. doi: 10.4154/gc.2008.25 bellwood, d.r. (1996): the eocene fishes of monte bolca; the earliest coral reef fish assemblage.− coral reefs, 15/1, 11−19. doi: 10.1007/bf01626074 bellwood, d.r., goatley, c.h.r., brandl, s.j. & bellwood, o. (2014): fifty million years of herbivory on coral reefs: fossils, fish and functional innovations.− proc.of the royal society b, 281/1781, 1−8. doi: 10.1098/rspb.2013.3046 bellwood, d.r. & schultz, o. (1991): a review of the fossil record of the parrotfishes (labroidei: scaridae) with a description of a new calotomus species from the middle miocene (badenian) of austria.– ann. naturh. museum wien, 92 a, 55−71. blot, j. & tyler, j.c. (1990): new genera and species of fossil surgeonfishes and their relatives (acanthuroidei, teleostei) from the eocene of monte bolca, italy, with application of the blot formula to both fossil and recent forms.− st. ric. giac. terz. bolca, 6, 13–92. figure 4. acanthuridae fossil tooth, a) labial side; b) lingual side. g eo lo gi a c ro at ic a geologia croatica 69/2204 bošnjak, m., karaica, b., sremac, j., vrsaljko, d., hajek-tadesse, v., gruber, a., jeftinić, s.& posedi, n. (2014): middle miocene fossil assemblages and environments in the wider area of veternica cave (sw medvednica mt., nw croatia).– acta mineralogica-petographica, abstract series (5th international students geological congress), volume 8, p. 11. bošnjak makovec m., karaica, b., sremac, j., vrsaljko, d., hajek– tadesse, v., gruber, a., jeftinić, s. & posedi, n. (2015): miocene dolje development – dubravica locality.– in: vrsaljko, d., sremac, j. & bošnjak makovec, m. (eds.): international scientific meeting 100th birth anniversary of vanda kochansky-devidé, full member of academy, zagreb, 9th-11th april, field trip excursion guidebook, 3−7. kochansky, v. (1944): fauna marinskog miocena južnog pobočja medvednice (zagrebačke gore). [miozäne marine fauna des südlichen abhanges der medvednica (zagreber gebirge)].− geol. vjesnik hrv. drž. geol. zav. hrv. drž. geol. muz., vol. 2/3, 171−280. kochansky-devidé, v. (1957): o fauni miocena i o tortonskom „šliru“ medvednice (zagrebačka gora). [über die fauna des marinen miozäns und über den tortonischen „schlier“ von medvednica (zagreber gebirge)].− geol. vjesnik, 10 (1956), 39−50. kochansky-devidé, v. & bajraktarević, z. (1981): miocen (baden i sarmat) najzapadnijeg ruba medvednice. [miozän (baden und sarmat) des westlichen randes von medvednica gebirge (kroatien, jugoslawien)].− geol. vjesnik, 33, 43–48. ludt, w. b., rocha, l. a., erdmann, m. v. & chakrabarty, p. (2015): skipping across the tropics: the evolutionary history of sawtail surgeonfishes (acanthuridae: prionurus). molecular phylogenetics and evolution, 84, 166–172. doi: 10.1016/j.ympev.2014.12.017 meyer, h. v. (1842): iguana (?) haueri, aus dem tertiärgebilde des wiener beckens.− beiträge zur petrefacten-kunde, 5, 33−34. pavelić, d. (2002): the south-western boundary of central paratethys.– geologia croatica, 55/1, 83–92. doi: 10.4154/gc.2002.08 pellissier, l, leprieur, f., parravicini, v., cowman, p. kulbicki, m., litsios, g., olesen, s., wisz, m. s., bellwood, d.r., & mouillot, d. (2014): quaternary coral reef refugia preserved fish diversity.– science, 344, 1016−1019. doi: 10.1126/science.1249853 pikija, m. (2009): litavac i klastične naslage s vulkanitima (baden – m4).− in: velić, i. & vlahović, i. (eds.): tumač geološke karte republike hrvatske 1:300.000 (geological map of the republic of croatia). hrvatski geološki institut, zagreb, 86−87. purcell, s. w. & bellwood, d. r. (1993): a functional analysis of food procurement in two surgeofishes species acanthurus nigrofuscus and ctenochaetus striatus (acanthuridae).− envir. biology of fishes, 37, 139−159. randall, j. e. (2001): surgeonfishes of hawai’i and the world.− mutual publish. and bishop museum press hawai’i. schultz, o. (2003): the middle miocene fish fauna (excl. otolithes) from mülbach am manhartsberg and grund near hollabrunn, lower austria.− ann. naturh. museum wien, 104 a, 185−193. schultz, o. & bellwood, d. r. (2004): trigonodon oweni and asima jugleri are different parts of the same species trigonodon jugleri, a chiseltooth wrasse from the lower and middle miocene of central europe (osteichthyes, labridae, trigonodontinae).– ann. naturh. museum wien 105a, 287–305. sorbini, l. & tyler, j.c. (1998a): a new genus and species of eocene surgeonfish (acanthuridae) from monte bolca, italy, with similarities to the recent zebrasoma.− st. ric. giac. terz. bolca, 7, 7–19. sorbini, l. & tyler, j.c. (1998b): a new species of the eocene surgeon fishgenus pesciarichthys from monte bolca, italy, with comments on caudal peduncle armature and supraneurals in acanthurids.− st. ric. giac. terz. bolca, 7, 21–34. sorenson, l., santini, f., carnevale, g. & alfaro, m. e. (2013): a multilocus timetree of surgeonfishes (acanthuridae, percomorpha) with revised family taxonomy.− mol. phylogenet. evol., 68/1, 150−160. doi: 10.1016/j.ympev.2013. 03.014 šikić, k., basch, o. & šimunić, a. (1977): osnovna geološka karta sfrj 1:100000, list zagreb l38-80 [basic geological map of sfry 1:100000, zagreb sheet – in croatian].− institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd. šikić, k., basch, o. & šimunić, a. (1979): osnovna geološka karta sfrj 1:100000. tu mač za list zagreb l 38-80 [basic geological map of sfry 1:100000, geology of the zagreb sheet – in croatian].− institut za geološka istraživanja, zagreb (1972) savezni geološki zavod, beograd, 81 p. šikić, k. (1995): geološki vodič medvednice. institut za geološka istraživanja inaindustrija nafte, d.d., zagreb, 199 p. tripalo, k., japundžić, s., sremac, j. & bošnjak makovec, m. (2015): prvi nalaz ribe-kirurg u miocenskim naslagama medvednice. [first record of the surgeonfish from the miocene deposits of mt. medvednica].– in: mauch lenardić, j., hernitz kučenjak, m., premec fućek, v. & sremac, j. (eds.): international scientific meeting 100th birth anniversary of vanda kochansky-devidé, full member of academy − zagreb, 9th-11th april 2015, abstracts, hrvatska akademija znanosti i umjetnosti, zagreb, 80−81. tyler, j.c. (1970): osteological aspects of interrelationships of surgeon fish genera (acanthuridae).− proc. acad. nat. sci. phila., 122, 87−124. tyler, j.c. (1997): the miocene fish marosichthys, aputative tetraodontiform, actually a perciform surgeon fish (acanthuridae) related to the recent naso.− beaufortia, 47, 1–10. tyler, j.c. (1999): a new genus and species of surgeon fish (acanthuridae) with a unique dorsal-fin pterygiophore arrangement from the eocene of monte bolca, italy.− st. ric. giac. terz. bolca, 7, 245–256. tyler, j.c. (2000): arambourgthurus, a new genus of hypurostegic surgeon fish (acanthuridae) from the oligocene of iran,with a phylogeny of the nasinae.− geodiversitas, 22, 525–537. tyler, j.c. (2005a): redescription and basal phylogenetic placement of the acanthurid surgeon fish gazolaichthys vestenanovae from the eocene of monte bolca, italy (perciformes; acanthuroidea).− st. ric. giac. terz. bolca, 11, 97–117. tyler, j.c. (2005b): a new genus for the surgeon fish acanthurus gaudryi de zigno 1887 from the eocene of monte bolca, italy, a morphologically primitive basal taxon of acanthuridae (acanthuroidea, perciformes).− st. ric. giac. terz. bolca, 11, 149–163. tyler, j.c. & bannikov, a.f. (2000): a new species of the surgeon fishgenus tauichthys from the eocene of monte bolca, italy (perciformes, acanthuridae).− boll. mus. civ. st. nat. verona, 24, 29–36. tyler, j.c. & sorbini, l. (1998): on the relationships of eonaso, an antillean fossil surgeon fish (acanthuridae).− st. ric. giac. terz. bolca, 7, 35–42. tyler, j.c. & micklich, n.r. (2011): a new genus and species of surgeon fish (perciformes, acanthuridae) from the oligocene of kanton glarus. switzerland.− swiss j. palaeontol., 130, 203–216. doi: 10.1007/s13358-011-0016-5 vrsaljko, d., pa ve lić, d., miknić, m., brkić, m., kovačić, m., heći mović, i., hajek-tadesse,v., avanić, r. & kurtanjek, n. (2006): middle miocene (upper badenian/sarmatian) palaeoecology and evolution of the environments in the area of medvednica mt. (north croatia).− geologia croatica, 59/1, 51−63. doi: 10.4154/gc.2006.04 vrsaljko, d., hećimović, i. & avanić, r. (2007): miocene deposits of northern croatia.– in: grgasović, t. & vlahović, i. (eds.): 9th international symposium on fossil algae – croatia 2007, field trip guidebook and abstracts. croatian geological survey, zagreb, 143−153. winterbottom, r. (1993): myological evidence for the phylogeny of recent genera of surgeonfishes (percomorpha, acanthuridae), with comments on the acanthuroidei.− copeia, 1, 21−39. doi: 10.2307/1446292 gc_2-2013_kb.indd sirel et al.: systematics and biostratigraphy of oligocene (rupelian-early chattian) foraminifera from lagoonal-very shallow water limestone... 83 geologia croaticageologia croatica geologia croatica 66/2 83–109 8 figs. 11 pls. zagreb 2013 ab stra ct the aim of the present work is to describe the oligocene (rupelian-early chattian) shallow water larger foraminifera from central turkey (sivas basin). among them is a new miliolid genus, sivasina n. gen. si̇rel & özgen-erdem (type species sivasina egribucakensis n. gen. n. sp. si̇rel & özgen-erdem), which occurs in the eğribucak, bakımlı, tuzlagözü and çaygören sections (e of sivas). one new rupelian-early chattian lagoonal very shallow water peneroplid species peneroplis fl abelliformis n. sp. si̇rel & özgen-erdem from the eğribucak, tuzlagözü and çaygören sections and rupelian lagoonal two new peneroplid species coscinospira sivasensis n. sp. si̇rel & özgen-erdem, coscinospira elongata n. sp. si̇rel & özgen-erdem from the eğribucak section (e of sivas), two new rupelian very shallow water alveolinid species praebullalveolina oligocenica n. sp. si̇rel & özgen-erdem and praebullalveolina minuta n. sp. si̇rel & özgen-erdem from the bakımlı section are described and fi gured. furthermore, details on several already known oligocene species are given (soritids: praearchaias diyarbakirensis si̇rel, praearchaias minimus si̇rel, archaias kirkukensis henson, archaias asmaricus smout & eames; austrotrillinids: austrotrillina brunni marie). in addition, the biostratigraphy of four studied sections is discussed. keywords: oligocene, benthic foraminifera, systematics, biostratigraphy, sivas basin, central turkey systematics and biostratigraphy of oligocene (rupelian-early chattian) foraminifera from lagoonal-very shallow water limestone in the eastern sivas basin (central turkey)  ercüment sirel1, nazire özgen-erdem*2 and özgen kangal2 1 department of geological engineering, ankara university, 06100 ankara, turkey; (sirel@ankara.edu.tr) 2 department of geological engineering, cumhuriyet university, 58140 sivas, turkey; (*corresponding author: nozgen@cumhuriyet.edu.tr) doi: 10.4154/gc.2013.07 1. introduction the scientifi c and technological research council of turkey (tübitak) project on the stratigraphy, sedimentology and basin development in the oligocene-miocene of sivas basin was carried out in 2009-2012 by the department of geological engineering of cumhuriyet (sivas), at the universities of ankara, hacettepe (ankara), dumlupınar (kütahya), ege (i̇zmir) and onsekizmart (çanakkale) and at the geological mapping department of mta. the oligocene (rupelian-early chattian) lagoonal-very shallow water larger foraminifera, including alveolinids, soritids, peneroplids, austrotrillinids and miliolids and their biostratigraphy were investigated as a part of this project. according to our current knowledge marine sediments of danian-bartonian age are very widespread in the territory of turkey. on the contrary, continental deposits are observed mostly after bartonian stage at the çankırı, sivas and similar basins, as well as those of oligocene age. throughout the mediterranean region, at the end of bartonian or at the beginning of priabonian, important paleogeographic, sedimentary and faunal (particularly in benthic foraminifera) changes occurred. these may be connected with tectonic movements geologia croatica 66/2geologia croatica 84 (particularly orogeny) causing major regressions. these changes are refl ected in different ways in the study area, resulting in different facies developments benthic foraminiferal assemblages. the lagoonal, very shallow to and shallow water limestones in the eğribucak, bakımlı, tuzlagözü and çaygören sections and few spot samples from the eastern sivas basin yielded several new peneroplid, alveolinid, miliolid and known austrotrillinid and soritid species which are here described and fi gured. throughout the mediterranean region, the very shallow water marine environments with porcellaneous foraminifera are virtually absent in the depositional sequences of oligocene age. as yet, these depositional environments have been recorded from the middle-east, iran and iraq by henson (1950), smout & eames (1958), hottinger (2007), amirshahkarami & taheri (2009), amirshahkarami et al. (2010), benedetti (2010), seyrafian et al. (2011) and amirshahkarami (2013). in the mediterranean area exceptions containing the very shallow water marine limestone with benthic foraminifera have previously been reported from the forebetic of moratalla, spain (hottinger, 1963), france (bignot, 1972, p. 102, pl. 1, fi g. 4), priabona, italy (barbin & bignot, 1986; barbin et al., 1997; bassi et al., 2007), southern apulia (esu et al., 1994), sicily (benedetti, 2010) and the ionian islands, western greece (di carlo et al., 2010). in turkey, interesting early oligocene very shallow water marine spot limestone samples with porcellaneous foraminifera (mainly soritids, miliolids, peneroplids and austrotrillinids species) have previously been reported from the kırkbini village, sw diyarbakır, southern turkey by si̇rel (1996) and rupelian-early chattian very shallow water marine limestone sequence with soritids, miliolids and austrotrillinids species from the develi village, w of malatya, e turkey by si̇rel (2003, figs. 4, 14). in the studied area, interesting rupelian-early chattian lagoonal, four very shallow and shallow water lithologic successions were investigated with special reference to the description of the porcellaneous foraminiferal species and their biostratigraphy. they were measured from different localities of the eastern sivas basin, eastern part of central turkey (fig. 1) as follows. the eğribucak section, located near the eğribucak village (e of sivas) (fig. 2), is the type locality of several new foraminiferal taxa, namely, the new miliolid genus sivasina n. gen. (type species s. egribucakensis n. gen. n. sp.) and the new peneroplid species peneroplis fl abelliformis n. sp., coscinospira elongata n. sp. and c. sivasensis n. sp. s. egribucakensis n. gen. n. sp. and p. fl abelliformis n. sp. are recognized from the rupelian-early chattian (sbz 21, 22) sequ ence of the eğribucak section, whereas. c. sivasensis n. sp. and c. elongata n. sp. occur in the basal lagoonal clayey limestone of the rupelian sequence of the section. the top shallow water algal limestone contains miogypsinella borodinensis hanzawa, miogypsinella cf. complanata (schlumberger), marasella sp., postmiogypsinella sp. and an undetermined miogypsinid species indicating a late chattian age (sirel & işik, 2011; sirel & gedik, 2011). analogous chattian assemblages have been reported from the venetian area (ne italy) and from southern apulia (italy) by bassi et al. (2007) and benedetti & briguglio (2012), respectively. another interesting succesion, here referred to as the bakımlı section (fig. 3) (samples bak. 1 to 21) is situated southeast of the bakımlı village, e of sivas. the sandy limestone and limestone beds ranging from 15 to 21 are the type locality of p. oligocenica n. sp. and p. minuta n. sp. two additional known rupelian soritid species p. diyarbakirensis si̇rel and p. minimus si̇rel (si̇rel, 1996, pl. i and si̇rel, 2003, fig. 14) co-occur with the two new alveolinid species. figure 1: location map of study area and stratigraphic sections. 1 – eğribucak section, 2 – bakımlı section, 3 – tuzlagözü section, 4 – çaygören section, es – spot samples. sirel et al.: systematics and biostratigraphy of oligocene (rupelian-early chattian) foraminifera from lagoonal-very shallow water limestone... geologia croatica 85 the tuzlagözü section (fig. 4) is an interesting succesion for the shallow/very shallow water oligocene foraminifera, located se of tuzlagözü village, e of sivas. the very shallow water limestone samples ranging from tzg. 1 to tzg. 5 yielded s. egribucakensis, p. diyarbakirensis, p. minimus, p. fl abelliformis n. sp., peneroplis evolutus henson and a. kirkukensis henson of rupelian-early chattian age. on the contrary, the top shallow water algal limestone beds ranging from sample tzg. 6 to sample tzg. 8 comprise m. cf. complanata, marasella sp. (primitive type), an undetermined miolepidocyclinid species, planorbulina bronnimanni bignot & decrouez, spiroclypeus sp. and amphistegina sp. of late chattian age. the last studied section is çaygören (fig. 5) ranging from sample buc. 1 to sample buc. 15 is situated se of çaygören village, e of sivas. the lower part of the sequence, ranging from sample buc. 1 to buc. 12, is composed of limestone and sandy limestone with s. egribucakensis n. gen. n. sp. p. fl abelliformis n. sp., p. evolutus, peneroplis sp., archaias asmaricus smout & eames, and archaias sp. of rupelian-early chattian age (sbz 21, 22), thus indicating a very shallow water marine environment for the lower part of the oligocene çaygören sequence. conversely, the top shallow water algal limestone of the çaygören succession, ranging from sample buc. 13 to sample buc. 15, contains m. borodinensis, m. cf. complanata, marasella sp., postmiogypsinella sp. and undetermined miogypsinid species of late chattian age (sbz 23). the stratigraphic distributions in the studied sections of the here described rupelian–early chattian lagoonal-very shallow water foraminiferal species can be correlated with the shallow benthic zones of cahuzac & poignant (1997) and be referred to lagoonal-very shallow water environments. the description of the new foraminiferal taxa and the already known oligocene species is by e. si̇rel and n. özgen-erdem, as well as the interpretation of their structural elements, given in fig. 6. the eğribucak (fig. 2), bakımlı (fig. 3), tuzlagözü (fig. 4) and çaygören (fig. 5) sections were measured by n. özgen-erdem and ö. kangal. the chattian and miocene miogypsinid and other foraminiferal species are out of the scope of present study. all the random and oriented thin sections of the foraminiferal species described and fi gured in this paper are deposited in the collection of cumhuriyet university (sivas, turkey), under the labels shown in pls. i-xi. 2. studied sections in this chapter, the lithostratigraphic and biostratigraphic features of the studied sections (figs. 2-5) are summarized. the benthic foraminiferal biozones in the lithologic successions listed above are largely based on the sbz zonation by cahuzac & poignant (1997). the stratigraphic and environmental distributions of the oligocene lagoonal, very shallow and shallow water foraminiferal species are shown in figs. 7 and 8, respectively. 2.1. eğribucak section the well-exposed oligocene sequence with new lagoonalvery shallow foraminiferal species s. egribucakensis n. gen. n. sp., p. fl abelliformis n. sp, c. sivasensis n. sp and c. elongata n. sp. is located ne of eğribucak village, e of sivas (map reference i̇38; coordinates 39°43’48.08’’n; 37°16’33.84’’e). lithologically, the eğribucak section (fig. 2) commences with thick bedded sandstone (probably eocene in age) and ranges to the shallow water algal limestone with m. borodinensis, m. cf. complanata, marasella sp., postmiogypsinella sp. and an undetermined miolepidocyclinid species of late chattian age. as shown in fig. 2, the lagoonal argillaceous limestone with miliolids and peneroplids species, that lies between gypsum beds, has a particularly interesting foraminiferal content. the lithologic units and their foraminiferal content are given in fig. 2. 2.1.1. biostratigraphy the following biostratigraphic benthic biozones are recognized in the eğribucak succession. sbz 21–22 (rupelian-early chattian): the fi rst biostratigraphic unit ranging from eb. 11 to eb. 33 is defi ned by the fi rst and the last occurrences of s. egribucakensis.n. gen. n. sp. the fi rst appearance of m. borodinensis and m. cf. complanata defi nes the upper boundary of the unit. the occurrence of the lagoonal peneroplid species p. fl abelliformis n. sp, c. sivasensis n. sp., c. elongata n. sp. and known peneroplid species p. evolutus is recognized in the basal level of this zone (fig. 2). sbz 23 (late chattian): the unit ranging from eb. 34 to eb. 37 is characterized by the presence of m. borodinensis and m. cf. complanata. 2.2. bakımlı section this is the most representative succession in the territory of turkey as regards the rupelian very shallow water limestone with the new alveolinid species praebullalveolina oligocenica and p. minuta. the outcrop (fig. 3) is situated 2 km se of bakımlı village, se hafi k, ne sivas (map reference i̇38, coordinates 39°17’78’’n; 37°29’13.11’’e). the eocene sequence ranging from bak. 1 to bak. 13 is composed of alternation of marl, sandstone and sandy limestone beds. the second lithostratigraphic unit ranging from bak. 14 to bak. 21 consists of very shallow water marine limestone with benthic foraminiferal species of rupelian age (sbz 21). the third lithostratigraphic unit, which is composed of sandstone and siltstone (fig. 3), was likely deposited in a continental environment. the lithologic units and their very shallow/shallow water benthic and planktonic (determined by dr. aynur hakyemez) foraminiferal species are given in fig. 3. 2.2.1. biostratigraphy sbz 21 (rupelian): the middle part of the bakımlı sequence (fig. 3) ranging from bak. 14 to bak. 21, yields a signifi cant very shallow water marine foraminiferal assemgeologia croatica 66/2geologia croatica 86 blage, that consists of p. oligocenica n. sp., p. minuta n. sp., p. diyarbakirensis, p. minimus, a. kirkukensis, a. brunni, s. egribucakensis n. gen. n. sp. and heterillina sp. of rupelian age. this foraminiferal association may be correlated with sbz 21 of cahuzac & poignant (1997) with borelis pygmaea (hanzawa), praerhapydionina delicata henson, bullalveolina bulloides reichel and austrotrillinid species of adams (1967) and corresponds to the early rupelian very shallow water limestone with p. diyarbakirensis, p. minimus, p. delicata, a. brunni and other species of diyarbakır region, se turkey (si̇rel, 1996, 2003, fig. 14). 2.3. tuzlagözü section a further interesting oligocene succession (fig. 4) with peneroplids, soritids, miliolids and miogypsinids species is situfigure 2: stratigraphic distribution of the foraminiferal species in the eğribucak section. sirel et al.: systematics and biostratigraphy of oligocene (rupelian-early chattian) foraminifera from lagoonal-very shallow water limestone... geologia croatica 87 figure 3: stratigraphic distribution of the foraminiferal species in the bakımlı section. figure 4: stratigraphic distribution of the foraminiferal spe cies in the tuzlagözü section. geologia croatica 66/2geologia croatica 88 ated near the tuzlagözü village, s zara town, e of sivas (map references i̇38; coordinate 39°42’45’’n; 37°40’ 41.23’’e). the section commences with limestone and ends with marl beds of early miocene age (fig. 4). the lower part of the tuzlagözü succession that ranges from sample tzg. 1 to sample tzg. 5 deposited in very shallow water marine environment with peneroplids, soritids and miliolids species of rupelian-early chattian age, as opposed to the upper part of the sequence, in which the algal limestone with miogypsinid species are developed in a deeper, shallow water environment. the lithologic units and their very shallow/shallow water foraminiferal species are given in fig. 4. 2.3.1. biostratigraphy the following benthic biozones are recognized in the lithologic succession of the tuzlagözü section. sbz 21–22 (rupelian-early chattian): defi ned by the biostratigraphic range of s. egribucakensis n. gen. n. sp. foraminiferal species such as a. kirkukensis, p. diyarbakirensis, p. fl abelliformis n. sp., p. evolutus and miliolids are recognized in this biostratigraphic unit. the upper boundary of the unit is defi ned by the fi rst appearance of the late chattian species m. cf. complanata, marasella sp. and an undetermined miolepidocyclinids species similar to that of si̇rel & gedi̇k (2011, pl. iii, fi gs. 4–6). sbz 23 (late chattian): the biostratigraphic zone ranges from tzg. 6 to tzg. 8. as mentioned above, this unit is characterized by the occurrence of m. cf. complanata, p. bronnimanni, marasella sp. and undetermined miolepidocyclinid species. 2.4. çaygören section the studied section (fig. 5) is located 10 km se of çaygören village, e sivas (map references i̇ 38, coordinates 39°44’ 26.92’’n; 37°16’07.94’’e). the fi rst lithostratigraphic unit, ranging from buc. 1 to buc. 12, consists of alternating sandstone, marl and sandy limestone with soritids, miliolids and peneroplids species of rupelian-early chattian age, which indicate a very shallow water marine environment for this unit. the shallow water marine algal limestone with miogypsinids of late chattian age is found at the top of the çaygören section. the lithologic units and their very shallow/shallow foraminiferal species are given in fig. 5. 2.4.1. biostratigraphy the following two biostratigraphic units are recognized in the çaygören succession (fig. 5). sbz 21–22 (rupelian-early chattian): the stratigraphic range of s. egribucakensis n. gen. n. sp. defi nes this unit. figure 5: stratigraphic distribution of the foraminiferal species in the çaygören section. sirel et al.: systematics and biostratigraphy of oligocene (rupelian-early chattian) foraminifera from lagoonal-very shallow water limestone... geologia croatica 89 additional species, such as p. evolutus, p. fl abelliformis n. sp., a. asmaricus, praearchaias sp., archaias sp. and miliolids, are observed in this unit. the fi rst occurrence of m. borodinensis marks the upper boundary of the unit. sbz 23 (late chattian): the fi rst and the last occurrence of m. borodinensis defi ne the lower and upper boundaries of this zone, respectively. the occurrence of postmiogypsinella sp. and marasella sp. in the unit is noteworthy, and thus this foraminiferal assemblage can be correlated with the late chattian assemblages described by si̇rel & işik (2011) and si̇rel & gedi̇k (2011). 3. systematic paleontology family: peneroplidae schultze, 1854 genus: peneroplis de montfort, 1808 type species: nautilus planatus fichtel & moll, 1798 peneroplis fl abelliformis n. sp. – si̇rel & özgen-erdem (pl. i, figs. 1–14; pl. ii, figs. 1,2; fig. 6a–c) origin of name: the test of the new species resembles a fan. holotype: almost centered equatorial section, illustrated in fig. 6b (label, eb. 11/36). paratypes: illustrated in pl. i, fi gs. 1–14; pl. ii, fi gs. 1,2; fig. 6 a–c; labels indicated in pl. i and ii and fig. 6. material: more than 120 specimens in equatorial, subequatorial and axial sections from the type locality. depository: holotype and paratypes are deposited in the collection of cumhuriyet university (sivas, central turkey). type locality: eğribucak section (fig. 1), ne of eğribucak village, e sivas, central turkey, (map reference i̇38, coordinate 39°43’48.08’’n; 37°16’33.84’’e). type level: rupelian-early chattian (sbz 21–22). description: the porcellaneous, calcareous test of the new species is composed of three growth stages, namely, small and arcuate early chambers are lined up in two planispiral-involute whorls, later low and broad chambers fl aring and arranged in peneropline and fl abelliform mode, senile chambers become cyclical (pl. i, fi g. 12; figs. 6a, b). diameter of the spheric protoconch ranges from 0.05 to 0.08 mm. the connection between the early planispiral chambers is provided by single intercameral foramen (fig. 6a), whereas the aperture is composed of two rows of foramina in the fl abelliform chambers (figs. 6a, c). the largest diameters of the planispiral and cyclical stages reach 0.47 mm and 1.8 mm (measured from pl. i, fi gs. 7 and 12), respectively. the early planispiral-involute stage forms a swollen central boss on both sides of the test (pl. i, fi gs. 10–12). remarks: a fl abelliform-cyclical form was fi rst described and fi gured as peneroplis damesini henson from the late eocene of iraq by henson (1950, p.34–35, pl. 4, fi gs. 2,3,6; pl. 5, fi g. 1). unfortunately, the embryonic and nepionic stages (planispiral-involute chambers) have not been described adequately in the original defi nition of p. damesini. however, the new species differs from p. damesini in its smaller test and developed broad fl abelliform chambers. p. fl abelliformis n. sp. differs from the oligocene specimens determined as p.cf. damesini henson by hottinger (1963, p. 968, pl. iii, fi gs. 7, 8; text fi gs. q–r) in possessing a larger test, broader fl abelliform chambers and cyclical chambers. the new species is distinguished from the late eocene species indicated as p. cf. damesini henson by si̇rel & acar (1982, pl. 5, fi gs. 4, 7–9) in having a larger test, well-developed fl abelliform and cyclical chambers. stratigraphic and geographic distribution: the new species occurs in the lagoonal-very shallow argillaceous limestone of the eğribucak section (fig. 2) and in the very shallow water marine limestone of the tuzlagözü (fig. 4) and çaygören (fig. 5) sections. the very shallow water limestones with new species underlie algal limestone beds with m. borodinensis and m.cf. complanatus of late chattian age on the one hand, and it is associated in the very shallow water limestone of the tuzlagözü section (fig. 4) with p. diyarbakirensis, p. cf. minimus of rupelian age (si̇rel, 1996) on the other hand. therefore, the stratigraphic range of the new species is interpreted as rupelian-early chattian (sbz 21–22). peneroplis sp. (pl. ii, figs. 3–11; fig. 6f) synonymy: 2010. peneroplis sp., amirshahkarami & taheri, pl. 7, fi g. 1. description: compressed small test is composed of two stages. the early stage is enrolled planispirally and involute with numerous low arched chambers, later adult chambers are uncoiled and arranged in fl aring peneropliform pattern (pl. ii, fi gs. 5, 10, 11). the diameter of the planispiral early stage ranges from 0.25 to 0.43 mm and the longitudinal diameter of the adult test from 0.68 to 1 mm. the interior of the chamber is undivided. the connection of the planispiral early chambers is provided by a single intercameral foramen, whereas the connection between the adult chambers is provided by the numerous openings (fig. 6f). remarks: the peneroplid specimens illustrated in pl. ii, fi gs. 3–11 resemble the oligocene-aquitanian specimens described as peneroplis sp. by amirshahkarami & taheri (2010, pl. 7, fi g. 1). the specimens described here are poorly sectioned, so the apertural face cannot be investigated in detail. therefore we cannot decide whether they belong to peneroplis de montfort or laevipeneroplis sulc. for the time being, they are referred to as peneroplis sp. stratigraphic and geographic distribution: it is observed only in the lower level (sbz 21–22) of the eğribucak section (fig. 2), in association with p. fl abelliformis n. sp., c. sivasensis n. sp., c. elongata n. sp. and s. egribucakensis n. gen. n. sp. considering its stratigraphic level, a rupelian age for peneroplis sp. appears more probable than a broader rupelian-early chattian age. geologia croatica 66/2geologia croatica 90 plate i peneroplis fl abelliformis n. sp. si̇rel & özgen-erdem rupelian-early chattian, all fi gured specimens from eğribucak section, x40 1 – incomplete equatorial section, showing planispiral early, fl abelliform adult and cyclical senile chambers (holotype, label eb.11/36). 2 – incomplete equatorial section (paratype, label eb.11/64). 3 – equatorial section (paratype, label eb.11/46). 4 – equatorial section (paratype, label eb.11/107). 5 – axial section (paratype, label eb.11/40). 6 – equatorial section (paratype, label eb.11/40). 7 – equatorial section (paratype, label eb.11/101). 8 – incomplete equatorial section (paratype, label eb.11/21). 9 – equatorial section (paratype, label eb.11/76). 10 – slightly oblique axial section (paratype, label eb.13/19h). 11 – axial section (paratype, label eb.11/65). 12 – axial sections of the cyclical form (paratype, label eb.11/21). 13 – non centered equatorial section (paratype, label eb.11/21). 14 – subaxial sections of cyclical forms (paratype, label eb.13/1). scale bar: 0.25 mm sirel et al.: systematics and biostratigraphy of oligocene (rupelian-early chattian) foraminifera from lagoonal-very shallow water limestone... geologia croatica 91 plate ii peneroplis fl abelliformis n. sp. si̇rel & özgen-erdem rupelian-early chattian, all fi gured specimens from eğribucak section, x40 1 – incomplete equatorial section and equatorial sections of sivasina egribucakensis n. gen. n. sp. (mid-bottom and upper right) (paratype, label eb.11/71). 2 – incomplete equatorial sections (top), subaxial section (mid), equatorial sections of s. egribucakensis (bottom and upper left) (paratype, label eb.11/63). peneroplis sp. rupelian-early chattian, all specimens from eğribucak section, x40 3 – equatorial section (bottom left and almost equatorial section of coscinospira (upper) (label eb.11/25). 4 – equatorial section showing planispiral early and fan like adult chambers (label eb.13/19g). 5 – equatorial section (label eb. 11). 6 – equatorial section (label eb.11/98). 7 – equatorial section (left) and sivasina sp. (right), (label eb.11/11). 8 – equatorial section, note, numerous openings on the fl abelliform chamber, (label eb.11/73). 9 – equatorial section showing numerous openings on the fl abelliform chambers (label eb.11/123). 10 – equatorial section of young form, (label eb.31/1g). 11 – equatorial section showing numerous openings on the fl abelliform chambers (label eb.11/123). coscinospira sivasensis n. sp. si̇rel & özgen-erdem rupelian-early chattian, all specimens from eğribucak section, x40 12 – slightly oblique equatorial section, showing single foramen in the planispiral and cribrate aperture in the uncoiled chambers (paratype, label eb.11/03). 13 – equatorial section (paratype, label eb.11/18). 14 – equatorial section showing cribrate aperture in the last planispiral and uncoiled chambers (paratype, label eb.11/30). 15 – equatorial section showing cribrate aperture in the uncoiled, single foramen in the planispiral chambers (paratype, label eb.11/21). 16 – equatorial section of c. elongata n. sp. (paratype, label eb.11/10). 17 – equatorial section (paratype, label eb.11/57). 18 – equatorial section (paratype, label eb.11/45). scale bar: 0.25 mm geologia croatica 66/2geologia croatica 92 genus: coscinospira ehrenberg, 1839 type species: coscinospira hemprichii ehrenberg, 1839 diagnosis: the test is large, operculiniform (in c. sivasensis n. sp; pl. ii, fi gs. 14,17) or crosier-shaped (in c. elongata n. sp; pl. iii, fi gs. 6, 7, 11, 13) with imperforate, calcareous, porcellaneous wall. the early arcuate chambers are arranged planispirally for two or two and half whorls (pl. ii, fi gs. 12–18; pl. iii, fi gs. 5–8), later chambers are partly or entirely uncoiled and become rectilinear (pl. ii, fi gs. 15, 16; pl. iii, fi gs. 5–13). the connection between adjacent early planispiral chambers is provided by the intercameral foramen (pl. iii, fi gs. 2, 3, 10–13; figs. 6d–e). the aperture becomes cribrate in the last planispiral chambers (pl. ii, fi g. 14; pl. iii, fi gs. 1, 12) and in the rectilinear chambers (pl. iii, fi gs. 6, 10–13; figs. 6d–e). the size of the test and protoconch suggest the existence of both generations. figure 6: structural elements of the following oligocene lagoonal restricted marine and very shallow water marine benthic foraminiferal species. a–c – peneroplis fl abelliformis n. sp. si̇rel & özgen-erdem, a – equatorial section (holotype, label eb. 11/36), b – equatorial section (paratype, label eb. 11/35), c – tangential section (paratype, label eb. 11/25), d – coscinospira sivasensis n. sp. si̇rel & özgen-erdem equatorial section (holotype, label eb. 11/269, e – coscinospira elongata n. sp. si̇rel & özgen-erdem, equatorial section (paratype, label eb. 11/14), f – peneroplis sp. equatorial section), g, h – sivasina egribucakensis n. gen. n. sp. si̇rel & özgen-erdem, g – tangential section (paratypes, label eb. 33/1e-145), h – axial and tangential sections (paratypes, eb. 33/1e-08) all fi gs. x60. abbreviations: (fc) fl abelliform chambers, (ap) apertural pores, (if) intercameral foramen, (cc) cyclical chambers, (pc) planispiral chambers, (pr) protochonch, (uc) uncoiled chambers, (ca) cribrate aperture, (ta) terminal aperture, (pri) peristomal ribs, (ba) axial section of biumbilicate test. sirel et al.: systematics and biostratigraphy of oligocene (rupelian-early chattian) foraminifera from lagoonal-very shallow water limestone... geologia croatica 93 differential diagnosis: the crosier-shaped peneroplid foraminifer coscinospira ehrenberg (type species coscinospira hemprichii ehrenberg) was described from the holocene of the red sea by ehrenberg (1839). it has planispiral early chambers and uncoiled adult chambers with cribrate aperture in common with here described species c. sivasensis n. sp. and c. elongata n. sp (pl. ii, fi gs. 12–18; pl. iii, fi gs. 1–13). therefore the specimens illustrated in pls. ii, iii are here referred to the genus coscinospira ehrenberg. on the other hand, some crosier-shaped peneroplid specimens were described and fi gured as c. hemprichii from the holocene of red sea by hottinger et al. (1993, p. 69, pl. 76, fi gs. 1–12; pl. 77, fi gs. 1–8), in spite of the fact that they have numerous fi ssures on the uncoiled chambers (pl. 76, fi g. 7; pl. 77, fi gs. 4, 5). the genus coscinospira (particularly in c. elongata n. sp.) has its crosier test shape, planispiral early and rectilinear adult chambers in common with the eocene-holocene genus spirolina lamarck (type species spirolina cylindracea lamarck), but the former has a cribrate aperture in the last planispiral chambers of the early stage and rectilinear chambers of the adult stage. in contrast, in spirolina, the aperture is a single opening. coscinospira sivasensis n. sp. si̇rel & özgen-erdem (pl. ii, figs. 12–15, 17, 18; pl. iii, figs. 1–5; fig. 6d) origin of name: from sivas, a city in the eastern part of the central turkey, the type locality of the new species. holotype: illustrated in pl. iii, fi g. 2 (bottom; label-eb. 11/26. paratypes: illustrated in pl. ii, fi gs. 12–15; pl. iii, fi gs. 1,3–5 and fig. 6d; labels are given in pl. ii,iii and fig. 6d. material: fifty-fi ve specimens in random sections from the eğribucak section (fig. 2). depository: holotype and paratypes are deposited in the collection of cumhuriyet university (sivas, central turkey). type locality: eğribucak section (fig. 1), ne of eğribucak village, e sivas, central turkey, (map reference i̇ 38, coordinate 39°43’48.08’’n; 37°16’33.84’’e). type level: rupelian (sbz 21). description: both generations have a large, operculiniform (pl. ii, fi gs. 12, 14, 17) or short crosier-shaped test with imperforate, calcareous, porcellaneous wall. the diameter of the planispiral early stage ranges from 0.83 to 1.16 mm in megalospheric forms, and from 0.8 to 1.1 mm in microspheric forms. the relatively large, spheric megalosphere (0.083–0.100 mm in diameter) is followed by planispiral arcuate early chambers increasing suddenly in size in the last whorl (pl. ii, fi gs. 12, 14, 15, 17). there are 39 planispiral chambers in an equatorial section of 1.16 mm in diameter that are arranged in the three whorls (pl. ii, fi g. 18). later few adult chambers start to uncoil. microspheric forms are rather rare in respect to the megalospheric forms. the small, spheric microsphere (about 0.030 mm in diameter) is followed by arcuate early chambers, planispirally arranged. there are 34 and 37 planispiral early chambers in an equatorial section measured 0.76 mm (pl. ii, fi g. 15) and 1 mm in diameter (pl. ii, fi g. 17), respectively. later chambers tend to uncoil (pl. ii, fi gs. 12, 14–18) with cribrate aperture. stratigraphic and geographic distribution: the new species c. sivasensis n. sp. and c. elongata n. sp. are frequent in the clayey lagoonal limestone of the eğribucak (fig. 2) in association with p. fl abelliformis n. sp., peneroplis sp. and s. egribucakensis n. gen. n. sp. this lagoonal limestone with c. sivasensis n. sp. and c. elongata n. sp. lies in the lower level of sbz 21–22, therefore the stratigraphic range of these two species of coscinospira is considered as rupelian. coscinospira elongata n. sp. si̇rel & özgen-erdem (pl. ii, fig. 16; pl. iii, figs. 6–13; fig. 6e) origin of name: the uncoiled stage of the test is elongated as opposed to c. sivasensis. holotype: centered longitudinal section, illustrated in fig. 6e (label eb. 11/14). paratypes: illustrated in pl. iii, fi gs. 7–9, 11–13; labels are given in the pl. iii. material: fifty-fi ve specimens in random sections from the eğribucak section (fig. 2). depository: holotype and paratypes are deposited in the collection of cumhuriyet university (sivas, central turkey). type locality: eğribucak section (fig. 2), ne of eğribucak village, e sivas, central turkey, (map reference i̇ 38, coordinate 39°43’48.08’’n; 37°16’33.84’’e). type level: rupelian (sbz 21). description: the new species has an elongated, crosiershaped test with imperforate, calcareous, porcellaneous wall. the small, spheric megalosphere (0.050–0.075 mm in diameter) is followed by arcuate planispiral chambers with an intercameral foramen (fi g. 6e), later numerous adult chambers with cribrate aperture are uncoiled and lined up in a long series (pl. iii, fi gs. 9–13). there are 28 arcuate planispiral chambers in an equatorial section measuring 0.63 mm in diameter (pl. iii, fi g. 7). there are 16–17 dome-like uniserial chambers in the uncoiled stage measuring 2 mm in length (pl. iii, fi g. 13). the size of the uniserial chambers becomes constant during the late ontogeny (pl. iii, fi gs. 6, 7, 9, 11, 13). remarks: it is distinguished from the type species of the genus, c. hemprichii, in its larger test and longer biserial stage. the new species differs from c. sivasensis n. sp. in possessing smaller early planispiral and longer uniserial stages. super family miliolacea ehrenberg, 1839 family hauerinidae, schwager 1876 genus sivasina n. gen. si̇rel & özgen-erdem type species sivasina egribucakensis n. gen. n. sp. si̇rel & özgen-erdem origin of name: after sivas, a city in the eastern part of central turkey; gender: feminine. diagnosis of genus: the new miliolid genus has a biumbilicate, infl ated lenticular test with rounded-pointed periphery and trematophorate cribrate terminal aperture supported geologia croatica 66/2geologia croatica 94 plate iii coscinospira sivasensis n. sp. si̇rel & özgen-erdem rupelian-early chattian, all fi gured specimens from eğribucak section, x40 1 – equatorial sections (upper), axial and oblique sections of s. egribucakensis n. gen. n. sp. (bottom) (paratype, label eb.11/124a). 2 – equatorial section showing cribrate aperture in the uncoiled chambers (bottom) and subequatorial section (upper) (holotype, label eb.11/26). 3 – equatorial section (bottom) and oblique section of s. egribucakensis n. gen. n. sp. (upper) (eb.11/75). 4 – equatorial section (paratype, label eb.11/103). 5 – equatorial section (bottom) and uncoiled chambers of c. elongata n. sp. (paratype, label eb.11/50). coscinospira elongata n. sp. si̇rel & özgen-erdem 6 – centered longitudinal section showing cribrate aperture in the uncoiled chambers (paratype, label eb.11/21). 7 – centered longitudinal section (paratype, label eb.11/128). 8 – centered longitudinal section of the large specimen, tending to c. sivasensis n. sp. (paratype, label eb.11/49). 9 – centered longitudinal section (paratype, label eb.11/58). 10 – longitudinal section showing reproduction of the embryo (holotype, label eb.11/14). 11 – uncentered longitudinal section showing cribrate aperture in the rectilinear chambers, equatorial section of c. sivasensis n. sp. (mid-left) (paratype, label eb.11/88). 12 – almost longitudinal section showing single foramina in the planispiral and cribrate aperture in the uncoiled stages (left) and equatorial section of c. sivasensis n. sp. showing single foramen in the early planispiral chamber an cribrate aperture at the last chamber (upper right) (paratype, label eb.11/27). 13 – uncentered longitudinal section showing uncoiled chambers lined up in a long serie (paratype, label eb. 11/30). scale bar: 0.25 mm sirel et al.: systematics and biostratigraphy of oligocene (rupelian-early chattian) foraminifera from lagoonal-very shallow water limestone... geologia croatica 95 plate iv sivasina egribucakensis n. gen. n. sp. si̇rel & özgen-erdem rupelian-early chattian, all fi gured specimens from eğribucak section, x60 1 – axial section showing cribrate aperture lower ultimate chamber (paratype, label eb.33/1e). 2 – axial section (paratype, label eb.33/1e). 3 – axial section, a form (paratype, label eb.11/17). 4 – axial section of the biumbilicate specimens (mid-left) and tangential section passing from the rectilinear chambers showing apertural face with ribs (bottom) and cribrate aperture in the rectilinear chamber (paratype, label eb.33/1e-08). 5 – oblique section (paratype, label eb.33/1e). 6 – axial section with uncoiled chamber, b form (top) and oblique sections (bottom) (paratype, label eb.11/08). 7 – axial section (paratype, label eb.11/34). 8 – axial section (paratype, label eb.33/1e). 9 – equatorial section tending to uncoil (paratype, label eb.33/1e). 10 – axial section (top) and subequatorial section (bottom) (paratype, label eb.11/2). 11 – slightly oblique axial section (paratype, label eb.33/1e). 12 – axial section (paratype, label eb.33/1e). 13 – axial section, a form showing cribrate aperture at the upper penultimate chamber (paratype, label eb.33/1e). 14 – oblique section, b form (paratype, label eb.33/1e). scale bar: 0.166 mm geologia croatica 66/2geologia croatica 96 by thin ribs (pl. iv, fi gs. 1, 4, 13; pl. v, fi gs. 7, 8; pl. vi, fi gs. 4, 5), also known as= peristomal ribs (hottinger, 2006, p. 52), particularly in the last chambers of the planispiral stage (pl. v, fi g. 2; pl. vi, fi g. 6), and juvenile chambers of probably quinqueloculine arrangement in microspheric specimens (pl. iv, fi gs. 5, 11), and biloculine arrangement in megalospheric specimens (pl. iv, figs. 7, 8, 13). later planispiral-evolute (pl. iv, fi gs. 1, 7, 8, 13) undivided chambers increasing in breadth and height from the protoconch to the last chamber. the chambers of the fi nal stage are uncoiled and become rectilinear (pl. iv, fi g. 6; pl. vi, fi g. 5). the wall of the test is imperforate, calcareous and porcellaneous. the connection between adjacent planispiral chambers is provided by a single intercameral foramen (pl. iv, fi gs. 9, 10). the incompletely known apertural system of sivasina n. gen. (type species sivasina egribucakensis n. gen. n. sp.) is rather complicated. the aperture of the new genus is cribrate or with a sieve plate (pl. iv, fi g. 1), possesses teeth or pillars (pl. v, fi g. 6, pl. vi, fi g. 4) and peristomal rim (hottinger, 2006) (as illustrated in text-fi g. 6g, pl. iv, fi g. 4, pl. v, fi g. 7, pl. vi, fi g. 5) lining the upper part of the chamber interior in the vicinity of the aperture and projecting into the openings (pl. iv, fi g. 4; pl. v, fi gs. 7, 8; pl. vi, fi gs. 5, 6). differences in test size and shape suggest the existence of two generations, as indicated by the illustrated specimens (pl. iv, fi gs. 6, 13; pl. v, fi gs. 1, 3, 6; pl. vi, fi gs. 1, 5). differential diagnosis: the new genus has biumblicate test, planispiral-evolute adult chambers in common with middle eocene-holocene genus dendritina d’orbigny (type species dendritina arbuscula d’orbigny), but the former has a cribrate aperture, teeth/pillar and with peristomal thin ribs (hottinger, 2006, p. 52, fig. 12) (see pl. iv, fi gs. 1, 4, 13; pl. v, fi gs. 7, 8; pl. vi, fi gs. 5, 6), whereas the latter has an areal dendritic aperture (loeblich & tappan, 1987, p. 370, pl. 391, fi g. 3). some miocene biumbilicate forms with planispiral-evolute whorls were described and fi gured as peneroplis farsensis henson (1950, p. 33, pl. 5, fi gs. 3–6) from the miocene of iraq, syria and qatar. these middle east forms differ notably from the species of peneroplis de montfort in having planispiralevolute whorls and trematophorate aperture. according to the authors, this species could be accommodated in the new genus because of the structural elements of the aperture. also the oligocene specimens indicated as dendritina cf. rangi d’orbigny by henson (1950, p. 31, pl. 5, fi g. 2) closely resemble s. egribucakensis n. gen. n. sp. because of their biumbilicate test with planispiral-evolute whorls and trematophorid-like aperture. furthermore, oligocene specimens with biumbilicate test described and fi gured as peneroplis cf. elegans d’orbigny, peneroplis cf. farsensis henson, dendritina cf. rangi d’orbigny and peneroplis aff. honestus todd & post by hottinger (1963, pl.v, fi gs. 1–9) can be referred to sivasina because of their planispiralevolute whorls and structure of the aperture. the specimen recorded as dendritina rangi d’orbigny from the oligocene-lower miocene of the asmari formation (sw iran) by amirshahkarami et al. (2010, p. 81, pl. 2, fi g. 2) is identical with the specimen fi gured in the present work in pl. vi, fi g. 3. sivasina egribucakensis n. gen. n. sp. si̇rel & özgen-erdem (pl. iv, figs. 1–14; pl. v, figs. 1–10; pl. vi, figs. 1–6; figs. 6g, h) synonymy: 1950. peneroplis farsensis henson, p. 33, pl. 5, fi gs.3–6. 1963. peneroplis cf. elegans d’orbigny, hotting er, p. 969, pl. v, fi gs. 3–5. 1963. peneroplis cf. farsensis henson, hottinger, p. 969, pl. v, fi gs. 6,7; fig. 2 a, b. 1963. dendritina cf. rangi d’orbigny, hottinger, p. 970, pl. v, fi g. 8, fig. 2 e–g. 1963. peneroplis aff. honestus todd & post, hotting er, p. 969, pl. v, fi g. 9. 2010. dendritina rangi d’orbigny, amirsahka ra mi et al., p. 81, pl. 2, fi g. 2. origin of name: from the type locality egribucak, a village in the sivas basin, central turkey. holotype: axial section, b form?, illustrated in pl. vi, fi g. 4 (label bak. 16/16). paratypes: illustrated in pl. iv, fi gs. 1–14; pl. v, fi gs. 1–10; pl. vi, fi gs. 1–6; labels are given in pl. iv, v and vi. material: 140 specimens in random sections from the eğribucak section (fig. 2) depository: holotype and paratypes are deposited in the collection of cumhuriyet university (sivas, central turkey). type locality: eğribucak section (fig. 1), ne of eğribucak village, e sivas, central turkey, (map reference i̇ 38, coordinate 39°43’48.08’’n; 37°16’33.84’’e). type level: rupelian-early chattian (sbz 21–22). description: both generations have an infl ated, biumbilicate lenticular test with tremataphorid aperture. diameter of the test ranges from 0.66 to 0.9 mm in the megalospheric form and from 1to 2 mm in the microspheric form. the megalospheric test is small, biumbilicate with rounded periphery (pl. iv, fi gs. 3, 7, 8, 13; pl. v, fi gs. 1, 3, 6). the relatively large, spherical megalosphere (0. 066– 0.100 mm in diameter) is followed by probably bilocular early chambers (pl. iv, fi gs. 8, 13; pl. v, fi gs. 1, 3, 6), later dome-like adult chambers are arranged in an oscillating, planispiral-evolute pattern (pl. iv, fi gs. 7, 10, 13). the chambers increase in size gradually from the megalosphere to the last chamber. some equatorial and axial sections clearly show that the last three chambers tend to uncoil (pl. iv, fi gs. 3, 7, 8; pl. v, fi g. 6). the microspheric test is medium sized, biumbilicate lenticular with rounded to pointed periphery (pl. iv, fi g. 6; pl. vi, fi gs. 2, 4, 5). the small, spheric microsphere (about 0.05 mm in diameter) is followed by early chambers that are arranged probably in a quinqueloculine mode for one whorl (pl. iv, fi g. 14; pl. v, fi g. 10), later dome-like adult chambers sirel et al.: systematics and biostratigraphy of oligocene (rupelian-early chattian) foraminifera from lagoonal-very shallow water limestone... geologia croatica 97 plate v sivasina egribucakensis n. gen. n. sp. si̇rel & özgen-erdem rupelian-early chattian, all specimens from eğribucak section, x60 1 – axial and oblique sections (paratype, label eb.11/66). 2 – equatorial section (paratype, label eb.33/1e). 3 – axial section showing aperture at the upper penultimate chamber (paratype, label eb.33/1e). 4 – slightly oblique equatorial and axial sections (paratype, label eb.11/78). 5 – equatorial section with deformed last three chambers (paratype, label eb.33/1e). 6 – axial sections (paratype, label eb.33/1e-147). 7 – tangential section showing terminal aperture with thin ribs (paratype, label eb.33/1e-142). 8 – axial section showing apertural face with ribs at the upper ultimate chamber (paratype, label eb.33/1e-145). 9 – deformed subaxial section showing aperture with ribs at the upper ultimate chamber (paratype, label eb.33/1e). 10 – oblique sections (paratype, label eb.11/92). scale bar: 0.166 mm geologia croatica 66/2geologia croatica 98 plate vi sivasina egribucakensis n. gen. n. sp. si̇rel & özgen-erdem early rupelian, all fi gured specimens from bakımlı section, except fig. 6 from eğribucak section, x60 1 – subaxial section (bottom), subaxial section of praearchaias minimus si̇rel (mid) and tangential section of praebullalveolina sp. (paratype, label bak.16/5). 2 – axial section (paratype, label bak.16/2). 3 – slightly oblique equatorial section showing cribrate aperture in the uncoiled chambers (paratype, label bak.17/4). 4 – axial section, showing teeth/pillars in the ultimate chamber (holotype, label bak.16/6). 5 – axial section showing apertural face with ribs at the left penultimate chamber (paratype, label bak.17/4). 6 – equatorial section showing cribrate aperture in the last chamber (paratype, label eb.33/1e-95). praebullalveolina oligocenica n. sp. 7 – subequatorial section, showing main and secondary apertural foramina in the penultimate whorl (paratype, label bak.16/13). 8 – equatorial section of the small b form (paratype, label bak.16/13). scale bar: 0.166 mm sirel et al.: systematics and biostratigraphy of oligocene (rupelian-early chattian) foraminifera from lagoonal-very shallow water limestone... geologia croatica 99 are arranged in a planispiral-evolute mode. the last chambers have like trematophorate aperture with peristomal ribs and are uncoiled (pl. iv, fi g. 6; pl. vi, fi gs. 1, 3, 5). remarks: similarities and differences between s. egribucakensis n. gen. n. sp and other species are given in the differential diagnosis of the new genus. stratigraphic and geographic distribution: this new miliolid species occurs in the lagoonal restricted marine limestone-very shallow water marine limestone of all studied sections (figs 2–5). the interesting oligocene (rupelian-early chattian) lagoonal-very shallow water marine succession crops out in the vicinity of eğribucak village (e sivas). as seen in eğribucak section (fig. 2), the oligocene (rupelian-early chattian) sequence is composed of various lithologic units. the basal lagoonal argillaceous limestone with s. egribucakensis n. gen. n. sp p. fl abelliformis n. sp., peneroplis sp., c. sivasensis n. sp and c. elongata n. sp that lies between gypsum beds is noteworthy. on the other hand, s. egribucakensis n. gen. n. sp. was observed in the upper part of the rupelian-early chattian sequence along with peneroplids and miliolids species (see fig. 2). this species occurs also in the very shallow water marine limestone of the bakımlı section (fig. 3), associated with the soritid species p. diyarbakirensis, p. minimus and the new alveolinid species p. oligocenica n. sp. and p. minuta n. sp. of rupelian age. additional very shallow water foraminiferal species, a. kirkukensis, a. brunni and miliolids, occur in this biostratigraphic unit sbz 21 (rupelian). in addition, it occurs in the very shallow water marine limestone of the tuzlagözü section, associated with p. diyarbakirensis, p. minimus, a. kirkukensis, p. fl abelliformis n. sp., p. evolutus, archaias sp. and miliolids of rupelian-early chattian age (fig. 4). finally, it abounds in the rupelian-early chattian very shallow water marine limestone of the çaygören section (fig. 5), along with p. fl abelliformis n. sp., p. evolutus, a. asmaricus, praearchaias sp. and gavelinellinids. superfamily alveolinacea ehrenberg, 1839 family alveolinidae ehrenberg, 1839 genus praebullalveolina si̇rel & acar, 1982 type species praebullalveolina afyonica si̇rel & acar, 1982 re-description of genus: this alveolinid genus has slightly ovoid, subspherical/spherical to nautiloid test with alternating septula and chamberlets. the apertural face has one row of main apertures and secondary apertures of smaller diameter (pl. vi, fi g. 7; pl. vii, fi gs. 1, 2; pl. viii, fi gs. 1, 4). the postseptal passage is absent; in contrast, the preseptal passage is well developed and large. one row of alveoli communicate through secondary apertures in the previous septum with the preceding preseptal passage (pl. vi, fi g. 7; pl. vii, fi gs. 1–2; pl. viii, fi gs. 1, 4, 9). the juvenile stage of the microspheric form is composed of a small microsphere, two rows of quinqueloculine and one row of triloculine cycles (pl. vii, fi g. 1; pl. viii, fi gs. 1, 6, 9). moreover the early undivided chambers of the megalospheric generation are probably arranged in triloculine mode (pl. vii, fi g. 3); the large planispiral chambers are diveded by septula into numerous chamberlets; the ramifying septula generate small triangular spaces at the roof of the chambers, in which the small supplementary chamberlets are formed (pl. viii, fi gs. 3,7). dimorphism faint; late eocene-early oligocene. remark: in the original defi nition of praebullalveolina, two rows of alveoli connected with two rows of secondary apertures have previously been reported as a diagnostic characteristic of the genus by si̇rel & acar (1982, p. 823– 824). this late eocene-early oligocene alveolinid genus has defi nitely one row of main and secondary apertures. the undivided early stage consists of two cycles of quinqueloculine and later one cycle of triloculine chambers, that are well recognizable in the microspheric form. in addition, the supplementary chamberlets are present in the adult planispiral chambers. praebullalveolina oligocenica n. sp. si̇rel & özgen-erdem (pl. vi, figs. 7,8; pl. vii, figs. 1–9; pl. viii, figs. 1,2) origin of name: it is found in the early oligocene limestone. holotype: equatorial section, illustrated in pl. vii, fi g. 1 (label bak. 16/7). paratypes: illustrated in pl. vi. figs. 1, 7, 8; pl. vii, fi gs. 1–9; pl. viii, fi gs. 1, 2; labels are given in pls. vi–viii. material: 65 specimens in random sections from the bakımlı section, (fig. 3). depository: holotype and paratypes are deposited in the collection of cumhuriyet university (sivas, central turkey). type locality: bakımlı section (fig. 3), e of sivas, eastern part of central turkey, (map reference i̇ 38, coordinates 39°17’78’’n; 37°29’13.11’’e). type level: early rupelian (sbz 21). description: the specimens with coarser structure have a slightly nautiloid test (pl. vii, fi gs. 3,4). the axial and equatorial diameters range from 0.6 to 0.83 mm and from 0.83 to 1.05 mm, respectively. the new species has characteristically larger divided chambers when compared with the type species p. afyonica and the new species p. minuta n. sp. in well-preserved microspheric specimens, the very small protoconch is followed by two or possibly more cycles of quinqueloculine undivided early chambers (pl. vii, fi g. 1; pl. viii, fi g. 1). later undivided chambers are lined up in triloculine pattern (pl. vii, fi g. 1; pl. viii, fi g. 1) and the adult divided planispiral chambers that are characteristically broad and infl ated arranged in the planispiral whorls. the height of the planispiral chambers increases fi rst gradually from the undivided triloculine chambers towards the last whorl (pl. vii, fi g. 1; pl. viii, fi g. 1), then suddenly in height and length in the last whorl. there are eight divided chambers in the last whorl of the equatorial section, measuring 1 mm in diameter (pl. vii, fi g. 1) geologia croatica 66/2geologia croatica 100 plate vii praebullalveolina oligocenica n. sp. si̇rel & özgen-erdem early rupelian, all fi gured specimens from the bakımlı section, x 60 1 – centered equatorial section, b form, showing two whorl of quinqueloculine and one whorl of triloculine undivided chambers and planispiral adult chambers with main and secondary aperture (holotype, label bak.16/7). 2 – equatorial section (paratype, label bak.16/2). 3 – slightly oblique axial section, b form (paratype, label bak.16/5). 4 – subaxial section (paratype, label bak.16/1). 5 – slightly oblique subaxial section (paratype, label bak.16/6). 6 – slightly oblique non centered equatorial section (paratype, label bak.16/9). 7 – oblique section (paratype, label bak.16/5). 8 – non centered equatorial section (paratype, label bak.16/5). 9 – tangential section showing one row of alveols in the upper penultimate whorl (paratype, label bak.16/1). scale bar: 0.166 mm sirel et al.: systematics and biostratigraphy of oligocene (rupelian-early chattian) foraminifera from lagoonal-very shallow water limestone... geologia croatica 101 plate viii praebullalveolina oligocenica n. sp. si̇rel & özgen-erdem early rupelian, all fi gured specimens from bakımlı section, x60 1 – equatorial section, b form, showing two whorl of quinqueloculine undivided early chambers, one and half whorl of triloculine undivided chambers and planispiral adult chambers with main and secondary aperture (paratype, label bak.16/7). 2 – slightly oblique subequatoial section (paratype, label bak.16/7). praebullalveolina minuta n. sp. si̇rel & özgen-erdem 3 – uncentered equatorial section (paratype, label bak.16/5). 4 – subequatorial section, b form, showing main and secondary apertures (holotype, label bak.16/8). 5 – oblique section (paratype, label bak.16/8). 6 – centered oblique section, showing two rows of quinqueloculine, undivided early chambers, and one or more triloculine undivided chambers (paratype, label bak.16/5). 7 – oblique subaxial section (paratype, label bak.16/9). 8 – subaxial section showing small chamberlets (paratype, label bak.16/5). praebullalveolina sp. 9 – subequatorial section showing two may be more rows of quinqueloculine, undivided early chambers and planispiral, divided adult chambers with main and secondary aperture (label bak.16/1). scale bar: 0.166 mm geologia croatica 66/2geologia croatica 102 remarks: the new species differs from the type species of the genus p. afyonica in its larger test with larger divided planispiral chambers (pl. vii, fi gs. 1–2; pl. viii, fi gs. 1–2). in the holotype of p. oligocenica n. sp. there are eight divided chambers in the last whorl at an equatorial diameter of 1 mm (pl. vii, fi g. 1), whereas in p. afyonica there are 15 divided lower and smaller chambers in the last whorl at an equatorial diameter of 0.92 mm (si̇rel & acar 1982, pl. i, fi gs. 1,5). in addition, the chamberlets of p. oligocenica n. sp. are larger than the chamberlets of p. afyonica. the new species p. minuta n. sp. differs from p. oligocenica n. sp. in possessing smaller test with lower and narrower, numerous divided adult chambers with smaller chamberlets (pl. viii, fi gs. 4, 8). stratigraphic and geographic distribution: until 1998, the alveolinid genus praebullalveolina (type species p. afyonica) was considered as a marker species of the priabonian very shallow environment in the mediterranean region by si̇rel & acar (1982) and serra-kiel et al. (1998). the fi rst occurrence of praebullalveolina at the priabonian/oligocene boundary was reported from the priabona region (italy) by barbin et al. (1998). this biostratigraphic age concerning praebullalveolina was constrained by the presence of the associated early rupelian foraminiferal species p. delicata and austrotrillina paucialveolata grimsdale by barbin et al. (1998, p. 143). thus, the very shallow water marine limestone sequence (fig. 3) located near bakımlı village (e sivas) is particularly interesting, because here the two new species of praebullalveolina appear together with p. diyarbakirensis, p. minimus and other taxa (see fig. 3) of rupelian age (si̇rel, 1996). praebullalveolina minuta n. sp. si̇rel & özgen-erdem (pl. viii, figs. 3–8) origin of name: the test of the new species is smaller than that of the other known species of praebullalveolina. holotype: equatorial section, illustrated in pl. viii, fi g. 4 (label bak. 16/8). paratypes: illustrated in pl. viii, fi gs. 3–8; labels are given in pl. viii. material: 60 specimens in oriented and random sections from the bakımlı section. depository: holotype and paratypes are deposited in the collection of cumhuriyet university (sivas, central turkey). type locality: bakımlı section (fig. 1), e of sivas, eastern part of central turkey; (map reference i̇ 38, coordinates 39°17’78’’n; 37°29’13.11’’e). type level: early rupelian (sbz 21). description: the investigated specimens have a subspheric small test with imperforate, calcareous, porcellaneous wall. the axial and equatorial diameters range from 0.61 to 0.66 mm and from 0.70 to 0.78 mm, respectively. the test of the new species is composed of characteristically numerous narrow and low planispiral adult chambers with small chamberlets when compared with p. afyonica and p. oligofigure 7: stratigraphic distribution of the oligocene lagoonal-very shallow and shallow water foraminiferal species of the studied sections in the benthic biozonation of cahuzac & poignant (1997). figure 8: distribution of the larger benthic foraminiferal species in the lagoonal-very shallow–shallow marine environments of studied sections. sirel et al.: systematics and biostratigraphy of oligocene (rupelian-early chattian) foraminifera from lagoonal-very shallow water limestone... geologia croatica 103 cenica n. sp. in some sections, the very small protoconch is followed by two cycles of undivided quinqueloculine early chambers (pl. viii, fi g. 6), and later undivided chambers arranged in triloculine pattern as in p. oligocenica n. sp. (pl. viii, fi gs. 6, 8). the adult chambers are lined up in planispiral mode and divided into numerous chamberlets by septula. the height of the planispiral whorls increases gradually towards the last whorl. there are 14 divided planispiral chambers in the last whorl (holotype, pl. viii, fi g. 4) measuring 0.78 mm in diameter. remarks: p. minuta n. sp. differs from p. afyonica and p. oligocenica n. sp. in having smaller test, lower and narrower chambers with small chamberlets. stratigraphic and geographic distributions: its stratigraphic range and geographic distribution of p. minuta n. sp. coincide with those of p. oligocenica n. sp. superfamily soritacea ehrenberg, 1839 family soritidae ehrenberg, 1839 genus archaias de montfort, 1808 type species archaias spirans de montfort, 1808= nautilus angulatus fichtel & moll, 1798 archaias kirkukensis henson, 1950 (pl. ix, figs. 1–8; pl. x, fig. 14; pl. xi, fig. 1) synonymy: 1950. archaias kirkukensis henson, p. 43, pl. 7, fi gs. 3,4,9; pl. 8, fi gs. 1–5. 1950. archaias cf. aduncus (fichtel & moll), henson, p. 44, pl. 8, fi gs. 6,7. 1958. archaias kirkukensis henson, smout & eames, p.218, pl.40, fi gs.1–8; pl. 41, fi gs.12–19. 2003. archaias kirkukensis henson, si̇rel, pl. xiii, fi gs. 1–18. description: the species has a discoidal test with swollen central boss. the diameter of the test ranges from 2.56 to 3.06 mm. the very small microsphere is followed by small undivided, arcuate chambers lined up in a planispiral pattern for one and half whorls, later divided chambers with interseptal partitions arranged in a cyclical mode (pl. ix, fi gs. 1, 3–8). stratigraphic and geographic distribution: the species was reported from the late oligocene of the type locality, kerkük, iraq by henson (1950, p. 43). it has been found in the oligocene of sivas, central turkey, by turnovsky (1955) and van bellen (1956). the occurrence of a. kirkukensis in the rupelian-early chattian (sbz 21, 22) very shallow water limestone was recognized in the neighbouring locality of akçadağ (malatya, eastern turkey) by si̇rel (2003, p. 295, fi g. 4), where it overlies beds with nummulites gr. fabianii, n. cf. incrassatus de la harpe, rhabdorites cf. malatyaensis (si̇rel), asterigerina rotula (kaufmann) and orthophragminid species of priabonian age and it underlies beds with m. complanata and m. borodinensis of late chattian age (si̇rel, 2003, p. 273, fi g. 4). archaias asmaricus smout & eames, 1958 (pl. ix, figs. 9–16) synonymy: 1958. archaias hensoni smout & eames, p. 220, pl. 40, fi gs. 20–24; pl. 41, fi gs. 7,10,20. description: the defi nition of this species is based on the holotype of a. asmaricus (smout & eames 1958, pl. 41, fi g. 7). the species has an infl ated lenticular test with rounded periphery. the thickness of the swollen central part decreases toward the periphery (pl. ix, fi gs. 10–16). the diameter of the test ranges from 1.66 to 2.33 mm, the central thickness from 0.73 to 0.83 mm and the peripheral thickness 0.33 to 0.43 mm. the protoconch is very small, followed by few undivided, arcuate small chambers (pl. ix, fi gs. 10, 11); later divided chambers are arranged in planispiral-involute mode (pl. ix, fi g. 9) and the following cyclical adult chambers are divided by thin interseptal partitions into numerous small chamberlets. stratigraphic and geographic distribution: this species is found in the very shallow water marine limestone of the tuzlagözü section (fig. 4) with soritid species a. kirkukensis of rupelian-early chattian age (sbz 21,22). family soritidae ehrenberg, 1839 genus praearchaias si̇rel, 1996 type species praearchaias diyarbakirensis si̇rel, 1996 praearchaias diyarbakirensis si̇rel, 1996 (pl. x, figs. 1–8) synonymy: 1996. praearchaias diyarbakirensis si̇rel, p. 168–169, pl. 1,fi gs. 1–7, 13–17. 2003. praearchaias diyarbakirensis si̇rel, si̇rel, p. 296, pl. x, fi gs. 17–19. 2004. praearchaias diyarbakirensis si̇rel, si̇rel, p. 52, pl. 48, fi gs. 1–7, 13–17, 9. 2007. archaias operculiniformis henson, hottinger, p. 12, pl. 8, fi gs. 4,6,7; pl. 10, fi g. 8. 2007. archaias diyarbakirensis (si̇rel), hottinger, p. 13, pl. 7, fi gs. 2,4,7; pl. 13, fi g. 10; pl. 15, fi g. 7. 2010. praearchaias sp., benedetti, p. 202, pl. i, fi g. 8. description: the megalospheric test has an infl ated lenticular shape with imperforate, calcareous porcellaneous wall. the diameter of the test ranges from 1.6 to 2.6 mm and the thickness from 0.48 to 0.8 mm. the large, spherical megalosphere (about 0.160 mm in diameter) is followed by a semilunar second chamber (pl. x, fi g. 4), later by few undivided arcuate chambers and the last divided chambers of the adult stage are arranged in a planispiral-involute mode throughout ontogeny (pl. x, fi gs. 3, 4). the chambers are divided by complete or incomplete interseptal pillars (pl. x, fi gs. 4, 7). remarks: the genus praearchaias (type species p. diyarbakirensis) was fi rst described and fi gured from the oligocene of kırkbini village, sw of diyarbakır, se turkey by geologia croatica 66/2geologia croatica 104 plate ix archaias kirkukensis henson rupelian-early chattian, specimens illustrated in figs. 1, 2 from spot samples collected on the hafi k-sivas road (es), figs. 3–8 from tuzlagözü section, all fi gs. x30 1 – uncentered incomplete equatorial section, b form (label es. 1-l48). 2 – equatorial section of juvenile b form (label es.1m-l 46). 3 – subaxial section (label tzg. 1/8-6). 4 – tangential section showing interseptal pillars (label tzg. 2/1). 5 – incomplete subaxial section (label tzg. 1/2-2). 6 – centered axial section (label tzg.1/2-1). 7 – subaxial section (label tzg.1/6-6). 8 – axial section (label tzg.1/2). archaias asmaricus smout & eames rupelian-early chattian, specimens illustrated in figs. 9, 11–13, 15, 16 are from spot samples collected on the hafi k-sivas road (es), figs. 10, 14 from tuzlagözü section, x30 9 – subaxial section (label es.1f-k 521). 10 – centered incomplete equatorial section (label tzg.1/7). 11 – subequatorial section (label, es.1f-k 517). 12 – sub axial section (label es.1l-l51). 13 – oblique equatorial section (label es.1k-k 523). 14 – oblique equatorial section (label tzg.1/1b). 15 – oblique section (label es.1f-k516). 16 – subaxial section (label es.1l-l50). scale bar: 0.33 mm sirel et al.: systematics and biostratigraphy of oligocene (rupelian-early chattian) foraminifera from lagoonal-very shallow water limestone... geologia croatica 105 plate x praearchaias diyarbakirensis si̇rel early rupelian, all fi gured specimens from bakımlı section, x30 1 – subaxial sections (label bak. 16/14). 2 – oblique axial section (label bak.16/4). 3 – axial section (label bak.16/8). 4 – incomplete axial section (label bak.16/9). 5 – tangential section, showing cribrate aperture (mid) (label bak.16/9). 6 – tangential section (label bak.16/9). 7 – axial section with large megalosphere (bak.16/8). praearchaias minimus si̇rel early rupelian, specimens fi gured in figs. 8–10, 12, 13 from tuzlagölü section, fig. 11 from bakımlı section, all fi gs. x 30. 8 – axial section with small protochonch (label tzg. 2). 9 – equatorial section (label tzg. 2). 10 – axial section (label tzg. 1/6). 11 – axial section (label bak.17/1). 12 – axial section (label tzg. 2/1). 13 – axial section of broken specimen (label tzg. 2/1). 14 – a. kirkukensis, subaxial section of broken specimen (bottom), horizontal section of haymanella (top left) and peneroplis sp. (mid-top) (label tzg. 2/1). scale bar: 0.33 mm geologia croatica 66/2geologia croatica 106 si̇rel (1996, p. 168–169, pl. 1, fi gs. 1–7, 13–17). praearchaias differs strongly from archaias de montfort in that it is devoid of the cyclical adult chambers which are present in archaias. in addition, praearchaias has a cribrate areal aperture (si̇rel 1996, pl. i, fi gs. 1, 13,14; si̇rel, 2003, pl. xiii, fi gs. 8, 14, 18) instead of numerous pores on the peripheral band (si̇rel 2003, pl. xiii, fi gs. 7, 8). stratigraphic and geographic distribution: this early oligocene (rupelian) species is found in the very shallow water marine limestone of the bakımlı section (fig. 3) with the two new species, p. oligocenica n. sp. and p. minuta n. sp. it is found in the lower part of sbz 21–22 in the tuzlagözü section with additional foraminiferal species (see fig.4). praearchaias minimus si̇rel, 2004 (pl. x, figs. 8–13) synonymy: 1996. praearchaias sp. si̇rel, p. 169, pl. 1, fi gs. 8–12,18. 2003. praearchaias sp. si̇rel, si̇rel, p. 296, pl. x, fi gs. 8–12,18. 2004. praearchaias minimus si̇rel, p. 52, pl. 48, fi gs. 8–12, 17, 18. description: small, infl ated lenticular test with imperforate, calcareous, porcellaneous wall. the diameter of the test ranges from 0.8 to 1.3 mm and the thickness from 0.36 to 0.75 mm. the small, spheric megalosphere (0.08–0.13 mm in diameter) is followed by a semilunar second chamber (pl. x, fi gs. 8, 10, 13) and few undivided arcuate small chambers (pl. x, fi g. 9), later subrectangular adult chambers by interseptal pillars (pl. x, fi g. 9) are lined up in planispiralinvolute whorls throughout ontogeny. superfamily miliolacea ehrenberg, 1839 family austrotrillinidae loeblich & tappan, 1986 genus austrotrillina parr, 1942 type species trillina howchini schlumberger, 1893 austrotrillina brunni marie, 1955 (pl. xi, figs. 2–17) synonymy: 1955. austrotrillina brunni marie, p.203, pl.9, fi gs.4–8. 1968. austrotrillina brunni marie, adams, p.85, pl.6, fi gs. 6, 8. 2003. austrotrillina brunni marie, si̇rel, p.294, pl. x, fi gs. 10–16. description: the test is small and the peripheral margin is rounded. the transverse diameter of the test ranges from 0.88 to 1.19 mm, the longitudinal diameter from 1 to 1.27 mm. the spheric megalosphere (0.100–0.138 mm in diameter) is followed by small undivided chambers arranged in probably triloculine mode (pl. xi, fi gs. 2–6, 9, 11, 12, 14). later adult chambers with fi ne subepidermal partitions are also lined up in triloculine pattern (pl. xi, fi gs. 3, 12). two types of subepidermal partitions form small alveolar compartments (pl. xi, fi gs. 16, 20). plate xi early rupelian, all fi gured specimens from bakımlı section, all fi gs. x36, except fig. 1, x30 archaias kirkukensis henson 1 – incomplete equatorial section (label es.1k-k525). austrotrillina brunni marie 2 – transverse section (label bak.15a). 3 – transverse section (bak.15c). 4 – transverse section (label bak.18a). 5 – transverse section (label bak.15b). 6 – transverse section (label bak.17g). 7 – longitudinal section (label bak.15d). 8 – longitudinal section (label bak.15a). 9 – subtransverse section (label bak.15c). 10 – longitudinal section (label bak.15b). 11 – subtransverse section (label bak.15a). 12 – transverse section (label bak.15g). 13 – longitudinal section (label bak. 15c). 14 – transverse section (label bak.15f). 15 – sublongitudinal section (label bak.15c). 16 – tangential section showing subepidermal partitions (label bak.15a). 17 – transverse section (label bak.15d). austrotrillina sp1. 18 – longitudinal section (label bak.15e). 19 – transverse section (label bak.18a). 20 – tangential section showing subepidermal partitions on the external part of the chamber (label bak.15g). austrotrillina sp2. 21 – transverse section (label bak.15g). 22 – subtransverse section (label bak.15c). scale bar: 0.277, except fi g. 1 (0.33 mm) sirel et al.: systematics and biostratigraphy of oligocene (rupelian-early chattian) foraminifera from lagoonal-very shallow water limestone... geologia croatica 107 geologia croatica 66/2geologia croatica 108 stratigraphic and geographic distribution: this species is found in the rupelian very shallow water marine limestone of the bakımlı section (fig. 3) with p. oligocenica n. sp., p. minuta n. sp, p. diyarbakirensis and s. egribucakensis n. gen. n. sp. 4. conclusion and discussion throughout turkey, lagoonal-very shallow water marine limestone with porcellaneous calcareous foraminifera such as alveolinids, soritids, peneroplids, austrotrillinids and miliolids are virtually absent in the oligocene depositional successions. interesting exceptions are, early rupelian very shallow water marine spot limestone samples with soritids, peneroplids, austrotrillinids and miliolids which have previously been reported from the kırkbini village, sw of diyarbakır, southern turkey by si̇rel (1996) and the rupelian-early chattian very shallow water marine limestone sequence with mainly soritids and austrotrillinids species from the develi village, w of malatya, eastern turkey by si̇rel (2003, figs. 4, 14). the lagoonal-very shallow water marine oligocene successions recorsed here from the sivas basin with miliolids, alveolinids, peneroplids and soritids species are thus particularly noteworthy. the new miliolid genus sivasina n. gen. (type species s. egribucakensis n. gen. n. sp.) is unique among all foraminiferal taxa described here from the sivas basin, because it occurs in all studied sections (figs. 2–5). the lagoonal-very shallow water new miliolid species with trematophorate aperture occurs in the bakımlı section (fig. 3) with early rupelian species p. diyarbakirensis, p. minimus si̇rel (1996) on the one hand and it appears below the late chattian shallow water algal limestone of eğribucak section (fig. 2) with m. borodinensis and m. cf. complanata on the other hand. therefore, its biostratigraphic range has been interpreted as rupelian-early chattian (sbz 21, 22). the lagoonal argillaceous limestone observed between the gypsum beds in the eğribucak section (fig. 2) yielded abundant miliolid and peneroplid species such as s. egribucakensis n. gen. n. sp., p. fl abelliformis n. sp., peneroplis sp., c. sivasensis n. sp. and c. elongata n. sp. two new peneroplid species c. sivasensis n. sp. and c. elongata n. sp. and peneroplis sp. are only observed in the basal level of the oligocene sequence in the eğribucak section (fig. 2). considering the biostratigraphic range of s. egribucakensis n. gen. n. sp. in bakımlı section, a rupelian age has been inferred for these two new peneroplid species and peneroplis sp. the other species p. fl abelliformis n. sp. is found together with s. egribucakensis n. gen. n. sp. of rupelian-early chattian age in the eğribucak section (fig. 2). the two new alveolinid species p. oligocenica n. sp. and p. minuta n. sp. have only been found in the very shallow water marine limestone of the bakımlı section (fig. 3) with p. diyarbakirensis and p. minimus of early rupelian age. according to si̇rel (1996; 2003, fig. 14; 2004, s. 52), the two soritid species above and their accompanying taxa p. delicata and austrotrillina striata todd & post indicate an early rupelian age. in addition, the existence of praebullalveolina in the early rupelian very shallow water limestone of the priabona region,vicentin, italy (barbin et al., 1997), supports an early rupelian age for the two praebullalveolina species. acknowledgement this study was carried out as part of project çaydag-109y041, supported by the scientifi c and technological research council of turkey (tübitak). many thanks are due to prof. johannes pignatti (“la sapienza” university of rome, italy) for linguistic improvements of text. we thank to two anonymous reviewers for the helpful comments. references adams, c.g. (1965): the foraminifera and stratigraphy of the melinau limestone, sarawak and its importance in tertiary correlation.– quarterly journal geology london, 121, 283–338. adams, c.g. (1967): a revision of the foraminiferal genus austrotrillina parr.– british museum natural history bulletin geology, 16/2, 73–97. amirshahkarami, m. (2013): microfacies correlation analysis of the oligocene-miocene asmari formation, in the central part of the rag-e safi d anticlinal oil fi eld, zagros basin, south-west iran.– turkish journal of earth sciences, 22, 204–219. amirshahkarami, m. & taheri, a. (2010): biostratigraphy characterization of the rupelian-burdigalian carbonate succession at the chaman–bolbol area in the zagros basin.– stratigrapy and sedimentology researches, 26th year, 40/3, 119–136. amirshahkarami, m., ghabishavi, a. & rahmani, a. (2010): biostratigraphy and paleoenvironment of the larger benthic foraminifera in wells sections of the asmari formation from the rag-e-safi d oil fi eld, zagros basin, southwest iran.– stratigrapy and sedimentology researches, 26th year, 40/3, 63–84. barbin, v. & bignot, g. (1986): new proposal for an eocene-oligocene boundary according to microfacies from the priabonian type-section.– in: pomerol, ch. & premoli s.i. (eds): terminal eocene events. developments in paleontology and stratigraphy, 9, 49–52. barbin, v., decrouez, d. & menkveld-gfeller, u. (1997): présence de praebullalveolina à la limite eocéne supérieur/oligocéne dans la région de priabona vicentin, italie, alpes méridionales.– revue paléobiologie, genéve, 16/1, 139–144. bassi, d., hottinger, l. & nebelsick, j.h. (2007): larger foraminifera from the upper oligocene of the venetian area, northeast italy.– palaeontology, 50/4, 845–868. benedetti, a. (2010): biostratigraphic remarks on the caltavuturo formation (eocene-oligocene) cropping out at portella colla (madonie mts., sicily).– revue de paléobiologie, genève, 29/1, 197–210. benedetti, a. & briguglio, a. (2012): rizananeiza crassaparies n. sp. from the upper chattian of porto badisco (southern apulia, italy).– bolletino della società paleontologica italiana, 51/3, 167–176, modena. bignot, g. (1972): les microfaciés et leur utilisation stratigraphique.– mém.– bureau recherch. geol. min., 77, 93–107. cahuzac, b. & poignant, a. (1997): essai de biozonation del’oligo-miocène dans les bassins européens à l’aide des grands foraminifères néritiques.– bulletin de la société géologique de france, 168/2, 155–169. di carlo, m., accordi, g., carbone, f. & pignatti, j. (2010): biostratigraphic analysis of paleogene lowstand wedge conglomerates of a tectonically active platform margin (zakynthos island, greece).– journal of mediterranean earth sciences, 2, 31–92. sirel et al.: systematics and biostratigraphy of oligocene (rupelian-early chattian) foraminifera from lagoonal-very shallow water limestone... geologia croatica 109 d'orbigny, a. (1839): foraminiféres.– in: roman de la sagra. histoire physique politique et naturelle de l’ile cuba. arthus bertrand, paris. ehrenberg, c.g. (1839): uber die bildung der kreidefelsen und des kreidemergels durch unsichtbare organismen.– physikalische abhandlungender königlichen akademie der wissenschaften zu berlin, 59–147. esu, d., girotti, e., iannone, a., pignatti, j.s. & ricchetti, g. (1994): lagoonal-continental oligocene of southern apula (italy).– boll. soc. paleont.ital., 33, 183–195. henson, f.r.s. (1950): middle eastern tertiary peneroplidae (foraminifera) with remarks on the phylogeny and taxonomy of the family.– the west yorkshire printing co. limited, wakefi eld, england, 70p. hottinger, l. (1963): quelques foraminifères porcelanés oligocènes dans la série sédimentaire prébétique de moratalla (espagne méridionale).– eclogae geologicae helvetiae, 56, 963–972. hottinger; l. (2006): illustrated glossary of terms used in foraminiferal research.– carnets de géologie /notebooks on geology-memoir, 1–125. hottinger, l. (2007/06): revision of the foraminiferal genus globoreticulina rahaghi, 1978 and of its associated fauna of larger foraminifera from the late middle eocene of iran.– carnets de géologie – notebooks on geology, (cg2007-a06), 1–51. hottinger, l., halicz, e. & reiss, z. (1993): recent foraminiferida from the gulf of aqaba, red sea.– dela slovenska academia znanosti in umetnostni, ljubljana, (classis iv), 33, 179 p. loeblich, a.r. & tappan, h. (1987): foraminiferal genera and their classifi cation i.– van nostrand reinhold, new york, 970 p. marie, p. (1955): quelques formes nouvelles de polypiers et de foraminifères de i'oligocène et du miocène du n.w. de la grèce. ii. foraminifères.– bulletin de la société géologique de france, 6/5, 193–205. serra-kiel, j., hottinger, l., caus, e., drobne, k., ferràndez, c., jauhri, a.k., less, gy., pavlovec, r., pignatti, j., samsó, j.m., schaub, h., si̇rel, e., strougo, a., tambareau, y., tosquella, j., zakrevskaya, e. (1998): larger foraminiferal biostratigraphy of the tethyan paleocene and eocene.– bulletin de la societé géologique de france, 169/2, 281–299. seyrafian, a., vaziri-moghaddam, h., arzani, n. & taheri, a. (2011): facies analysis of the asmari formation in central and north-central zagros basin, southwest iran: biostratigraphy, paleoecology and diagnesis.– revista mexicana de ciencias geológicas, 28, 439–458. si̇rel, e. (1996): praearchaias, a new soritid genus (foraminiferida) and its oligocene shallow water foraminiferal assemblage from the diyarbakır region (se turkey).– geologica romana, 32, 167–181. si̇rel, e. (2003): foraminiferal description and biostratigraphy of the bartonian, priabonian and oligocene shallow water sediments of the southern and eastern turkey.– revue de paléobiologie, 22/1, 269–339. si̇rel, e. (2004): türkiye'nin mesozoyik ve senozoyik yeni bentik foraminiferleri.– jeoloji mühendisleri odası yayınları, emeğin bilimsel sentezi özel sayı 1, 219 p. si̇rel, e. & acar, s. (1982): praebullalveolina, a new foraminiferal genus from the upper eocene of the afyon and çanakkale region (w of turkey).– eclogae geologicae helvetiae, 73/3, 821–839. si̇rel, e. & gedi̇k, f. (2011): postmiogypsinella, a new miogypsinidae (foraminifera) from the late oligocene in malatya basin, turkey.– revue de paléobiologie, 30/2, 591– 603. si̇rel, e. & işik, u. (2011): marasella n. gen. (miogypsinidae, foraminiferida) and re-description of risananeiza boukhary, kuss & abdelraouf, 2008 from the late chattian of the maras region (s of turkey).– revue de paléobiologie, 30/1, 31–43. smout, a.h. & eames, f.e. (1958): the genus archaias (foraminifera) and its stratigraphical distribution.– palaeontology, 1/3, 207–225. turnovsky, k. (1955): notiz über peneropliden vorkommen in ostanatolien.– bulletin of the geological society of turkey, 6, 60–61. van bellen, r.c. (1956): the stratigraphy of the “main limestone” of the kirkuk, bai hassan and qarah chauq dagh structures in north iraq.– journal of the institute petroleum, 42, 233–263. manuscript received october 02, 2012 revised manuscript accepted april 30, 2013 available online june 19, 2013 geologia croatica 66/2geologia croatica 110 2019 | 72/1 | 43–49 | 8 figs. | 3 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction agricultural soil worldwide is seriously vulnerable to production losses due to the accumulation of salt. the impact of salts from the agricultural water return flow and capillary rise from the high-water table in some locations, increases the variable concentration of sulphate and chloride salts in agricultural fields through space and time. despite the general understanding of factors controlling salt distribution it remains difficult to extrapolate their spatial patterns on a large scale in the field. thus, spatial tools and techniques are needed to set background conditions and verify variations in salt distribution and their impacting factors. however, the presence of additional mineral phases on the surface of the crusts might affect the reflectance spectrum of the crusts. the present study was conducted using field crust samples to evaluate the factors affecting their spectra and distribution. earlier studies reveal that soil characteristics and salt minerals can be identified by examining absorption features using semantic and computational approaches (howari et al., 2002; drake, 1995; clark, 1999; zhang et al., 2013; araujo et al., 2014; soriano-disla jose et al., 2014; lapotre et al., 2017; robertson et al., 2016; araujo et al., 2014; wang et al., 2018). the absorption of the visible part of the electromagnetic spectrum happens when anionic groups, such as sulphate and carbonate, and bonded h2o molecules are present. since natural salts in soils contain these compounds, it is, in theory, possible to identify specific salt or evaporite minerals through spectral comparison with standard spectra libraries, identifying whether the evaporite is composed of pure minerals or admixtures. csillag et al. (1993) conducted a study on the spectra of soil samples from san joaquin in california and another set of hyperspectroscopic and microtopographic analyses of salt crust forms on arid, silty clay loam desert soils fares m. howari1, fatima al aydaroos2, yousef nazzal1, jibran iqbal1 and nadine bou orm1 1 zayed university, college of natural and health sciences, p o box 144534 abu dhabi, uae (corresponding author: fares.howari@zu.ac.ae; yousef.nazzal@zu.ac.ae; jibran.iqbal@zu.ac.ae; nadine.bouorm@zu.ac.ae) 2 uae space agency, abu dhabi, uae (f.alaydaroos@space.gov.ae) doi: 10.4154/gc.2019.01 abstract this paper describes simultaneous uses of field sampling and hyperspectroscopic approaches to understand the distributions of salt crusts and factors affecting them under field conditions. samples of salt affected soils and associated salt crusts that represented a range of soil salinities, slope, and moisture contents were gathered from the banks of the rio grande. the samples were studied for salt identification by optical microscopy and using a high-resolution spectroradiometer, ger 3700, and for salinity level, and moisture content by the wet chemistry method. the study identified two main groups of salt crusts, contaminated halite and gypsum crusts. reflectivity was correlated negatively with moisture content and positively with slope value, electrical conductivity and salt quantity. reflectivity of halite-dominated crusts was higher than those of gypsum. halite occurred over a greater range and higher slope values of soils than gypsum; however, a positive correlation between the slope and mean reflectivity of both salt crusts was reported. although reflectivity of salt crusts varied according to changes in moisture content, and the salinity of the soil, moisture content can drastically reduce the reflection more effectively? than the other factors. the data reported indicate the possibility of assessing the type of salt crust by estimation of the ratio of slope and reflectivity to the other variables. samples from hungary, specifically from the carpathian basin. they used a statistical approach in conjunction with a stepwise principal component band identification method to distinguish thirteen groups of soil salinity. they documented the significance of hyperspectroscopy techniques as a function of band width. the recognition accuracy decreased from 91 to 88% as the bandwidth decreased from 10–40 nanometers. the same study reported a positive correlation between the spectral pattern and the following parameters: clay fraction (0.85), organic matter (0.78), ph (0.75), salt fraction (0.73), and organic carbon (0.60). under field conditions, several factors affect the spectral profiles of salt crusts: the texture of the background soil, moisture content, and surficial contamination with other salts or minerals such as clay minerals or quartz. when an uncontaminated crust is developed as a result of evaporation of saline solutions, salt minerals with low solubility form first, and the surface of the crust is likely to be composed of salt minerals with the greatest solubility or in their sequence of their arrival at saturation (howari, 2004). this hypothesis, solubility-controlled system, was previously tested under controlled conditions (howari et al., 2000b, 2002; howari et al., 2002). the purpose of the present study was to examine the factors controlling the distributions of the different types of salt crusts. this presents an opportunity to couple such hyperspectroscpic methods and databases with new airborne sensor technologies to deal with soil quality problems and enhance the quality of the soil mapping process. 2. soil characterstcs salt crust samples were gathered from the upper 3–4 cm of the soil from the rio grande banks, three replicates were taken at each location for better representing the spatial variability of the article history: manuscript received february 16, 2018 revised manuscript accepted october 11, 2018 available online february 15, 2019 keywords: spectra, halite, gypsum, rio grande, soil, ger 3700 g eo lo gi a c ro at ic a geologia croatica 72/144 sites in the vicinity of el paso, texas (figure 1). relative topographic slopes in the investigated area varied from 1.3 to 17.5%. the general geology of the studied area is shown in figure 2. the soil is generally composed of arid, silty clay loam desert soils without definite horizons, and very low organic matter. visual observations in the field showed spotty salt crusts present in many areas around the sampled locations. some of the soils appeared leached and in the wetter areas, dark colored, cracked silty clay soils were present. areas along the bank and bed consist of alluvial or valley bottom very fine sand silty clay loams. the land surrounding the valley is mostly soils developed from surrounding igneous geology, and fine-grained alluvial materials of the rio grande sediment system, which include quartz and clay minerals. the bedrock of the study area is largely composed of limestone and dolomite. caliche is formed when ground water rich in dissolved calcium carbonate from these source rocks leaches up into the soil, then evaporates or retreats, leaving the calcium carbonate behind. over time, these soils are weathered by wind and rain, some soil is removed leaving only the hard cement-like caliche behind. this is why it is sometimes referred to as hard pan, because of the hard-impenetrable surface of exposed caliche in the soil. the major soils are mostly deep, brown or gray alkaline clays and loams. some are saline. most of the soils are used for rangeland to support grazing. other part, the soil is used to grow irrigated grain sorghums and vegetables are grown along the rio grande (figures 1 and 2). figure 1. location map of the study area. figure 2. main geological features of the rio grande valley showing (after villarreal-fuentes et al., 2016). figure 3. salt crust as appear under optical microscope (a, and b; 100x) and under binocular microscope (c to g; 20x). g eologia c roatica howari et al.: hyperspectroscopic and microtopographic analyses of salt crust forms on arid, silty clay loam desert soils 45 3. methodology soil samples (n=25) beneath the crusts were selected randomly from a salinized flood plan area tested for salinity by measuring electrical conductivity (ec) of a saturation extract, through a saturated soil paste made by gently dripping deionized h2o onto about 150 g of soil until the mixture became thick (e.g. wang et al., 2018). the thick paste was left for 2 hours before it was filtered by suction. the ec was measured on the filtrate using an ec-meter and reported as ds/m. measurement of soil moisture, and salt contents were determined by gravimetric methods. clinometers were used to measure the gradient of the soil surface. the salt crusts were tested using microscopic techniques with a nikon-eclipse me600l, and olympus microscopes. testing was accomplished under transmitted light at magnification up to 600 x for crystal characterization and to determine optical attributes. the salt crust was also investigated under cross polarized light for pleochroism, interference colors and birefringence of anisotropic crystals as well as under plane polarized light for crystal habit and relief. before taking the spectral reading, the water content in the soil samples was standardized by drying in an oven at 40oc for 24 hours to prevent chemical alteration and therefore changes in soil sample compositions. soon after, the soil samples were inserted in a desiccator for at least 24ours until the spectral readings were taken. the spectral reflectance reading from salt crusts was taken with a high-resolution spectroradiometer (model ger 3700) in a wavelength range from 500 to 2500 nm. this treatment was performed on a fraction of the collected samples in order to identify the minerals, another spectral run were performed on the bulk samples to study the impact of moisture content on the reflectance signatures. however, before starting the spectral reading, the instrument was calibrated by fixing it on a stand to measure the reflectance of its special white calibration panel. more details on spectral measurements are reported in howari et al. (2002). the spectral profiles were studied by computerized peak picking techniques using a spectral software package (specview). comparison between the groups and subgroups of samples involved use of analyses of variance (anova) one way layout figure 4. reflection spectra of halite and gypsum (250–2500 nm). g eo lo gi a c ro at ic a geologia croatica 72/146 design, principal component analyses (pca) and the f-test using excel and jmp/sas software packages (sall & ann, 1996). processed data were compared with the spectral data from nasa and usgs spectral libraries, and the spectral profiles and findings reported by crowely (1991), drake (1995), and howari et al. (2000 a, b and 2002). the data was firstly summarized and then the spectra were presented in terms of the mean plus and minus the standard deviation. then the emphasis was placed on evaluating which factors govern the greater variability of reflectance and crust formation. 4. results and discussion halite crusts have a glassy, transparent appearance with white to colorless, cubic to euhedral crystals (fig. 3 a). the surfaces of halite crusts were contaminated with quartz grains, and a claylike surface cover (fig. 3c). gypsum crusts appeared as white, transparent to translucent, and had prism-like to monoclincal shapes, with earthy to vitreous lustre. lamellae of successive zones of halite and gypsum crusts were observed in cross-sections prepared for crust collection (fig. 3). the shape of the spectral profile as well as the shape and location of the of the absorption band are significant in identifying and interpreting the spectral properties of salt crusts. the outlook of a spectral profile can be identified by the continuum slope and the intensity distribution, and the albedo. although albedo is the main source of variability, absorption characteristics have an important role in relation to certain chemical properties. in the tested soil samples, the highest reflectance value ranged from 25% to 45% (table 1). there are five regions of the mean spectra that demonstrate unique absorption properties and high differences among the tested soil spectra. these are located around 1000, 1400, 1900, 2200, 2300 nm (fig. 4). a crust with a certain grain size will have a particular reflectance, as when grain size changes, reflectance changes accordingly. it may increase or decreases as a function of the transparency and opacity of the material. halite, which cannot induce absorption bands in the visible and near thermal infrared (hunt et al., 1971 a, b; mougenot et al., 1993) had visible absorption features due to moisture and fluid inclusions or due to contamination and was placed at 1500, 1884, and 2245 nm (fig. 4). the surface of halite crusts is contaminated with materials from the surrounding soils which have plenty of quartz grains, and clay minerals (fig. 3). quartz is translucent, therefore, when its proportion in the soil or soil crust increases, light will more easily be transmitted through the crust, strengthening the detected band strength of absorbance properties in the reflectance spectra of halite crusts contaminated with quartz. the study observed a minor absorption feature present at 2310 nm. although not very visible, this absorption is related to the combination of -oh stretching mode with mg-o-h bending mode, and it is present in trioctahedral clays as described by pieters & englert (1993) and el-radaideh et al. (2017). the spectra shown in figure 3b had strong absorption features at 1024, 1226, 1780, and 2337 nm, and even stronger ones at 1458, 1866, and 1989 nm. those absorption features are known for gypsum. in gypsum the overtones or combination tones from fundamental vibrations of the water molecules produced a series of bands affecting the infrared spectrum between 1000 and 2500 nm, e.g. 1464, 1550, 1750, 1978 and 2300 nm (clark, 1999 and howari et al., 2002). these can be detected in the spectra of gypsum crusts (fig. 4a). however, the most dominant absorption features occurred at 1464, 1750 and 1978 nm. figure 5. soil characteristics under the gypsum and halite crust. table 1. correlation and test of significant among the studied soil parameters. variable by variable correlation count signif prob reflectance slope 0.1744 25 0.4044 ec slope 0.2735 25 0.1858 ec reflectance 0.3526 25 0.0839 moisture slope –0.3827 25 0.0590 moisture reflectance –0.1709 25 0.4139 moisture ec –0.5094 25 0.0093 quantity slope –0.2633 25 0.2035 quantity reflectance –0.2422 25 0.2434 quantity ec –0.1560 25 0.4564 quantity moisture 0.3115 25 0.1296 quantity slope –0.2633 25 0.2035 quantity reflectance –0.2422 25 0.2434 quantity ec –0.1560 25 0.4564 quantity moisture 0.3115 25 0.1296 quantity g/cm2 1.0000 25 0.0000 g eologia c roatica howari et al.: hyperspectroscopic and microtopographic analyses of salt crust forms on arid, silty clay loam desert soils 47 comparison of a group of variable differences obtained from gypsum and halite crusts is shown in figure 5, and table 2. a tool called a “diamond plot” was used to visualize the variability and results are shown in figure 4. it condensed essential information, group means, grand sample mean (the horizontal line in figure 5), confidence interval (ci), and raw data. a horizontal dotted line represents the grand sample mean. the diamond is the confidence interval for each group and the horizontal line within each diamond is the group means. the flatter the diamond, the tighter the ci. the groups of variables for halite concentrate figure 6. scatter plot illustrating the relationship between percent of low soil reflectivity and soil characteristics. figure 7. scatter plot illustrating the relationship between surface slop and percent of reflectivity. g eo lo gi a c ro at ic a geologia croatica 72/148 around the mean in a different pattern to those of gypsum. for example, reflectivity and value of gypsum concentrate below the grand mean and those of halite above the ground mean. testing the soil samples with low reflectance demonstrated that all of these also have high moisture content (figs. 6 and 7). the absorption bands are observed more clearly when the underlying soil samples have higher salt contents (fig 7). in the presented scatter plots, the ellipses surrounding the data points represent the 95% bivariate normal density ellipse, which is shown in each scatterplot. if each pair of variables has a bivariate normal distribution, this ellipse encloses approximately 95% of the points. the narrowness of the ellipse reflects the degree of correlation of the variables. if the ellipse is fairly round and is not diagonally oriented, the variables are uncorrelated. if the ellipse is narrow and diagonally oriented, the variables are strongly? correlated. correlations derived from the whole data sets yielded poor to good results, positive poor correlation was recorded between crust reflectivity and soil ec values with a significance probability of 0.08, whereas a negative correlation was recorded between reflectivity and moisture values with a significance probability of 0.4. a correlation coefficient of 0.4 is significantly stronger depending on the sample size and critical value for the number of data pairs. the correlation between slope and reflectivity was positive with significant probability of 0.4, indicating that slope is a relatively controlling factor for crust reflectivity (table 2, fig. 7). however, the mean of the relative slope for halite occurrences was 6.4% and for gypsum was 1.7 %. this could be due to drainage properties when drainage and slope gradient is efficient, and during the wet season the salts such as sodium chloride are washed down through the soil. this could suggest that soil with poor surface drainage will have much higher halite/gypsum ratios than soil in an area with good surface drainage. principal component analyses (pca) was applied to show which factor produce the greatest variability in the data (table 3). the analyses demonstrated that differences developed by salt quantity and slopes were grouped in the first and second pcs respectively. the low concentration of salts in the samples was considered a determining property for expression of the reflectance features. soils with salt content had low reflectance, primarily expressed through the first pc. the third source of variability produced from variations in moisture content that is correlated negatively with reflectivity, and slope. figure 8 shows a graphical representation of the ratio of the slope and reflectivity of gypsum and halite crusts as they relate to the other studied soil variables. it is possible to use this relationship to assess the type of crusts present. this could have several applications in reclamation appraisals, salinity management and in precision agriculture or satellite farming. the data presented demonstrate the influence of interlinked factors in controlling the field spectra. however, the spectra of salt crusts change with natural wetting or drying cycles or with man induced effects such as sprinkler irrigation, and this question is being investigated by comparing field and lab spectra simulated under various conditions including wetting, drying and spraying. once obtained, this knowledge together with previous data (e.g. crowely, 1991; drake, 1995 and howari et al., 2000 a, b and 2002) can be employed for agricultural land planning, management and reclamation purposes. 5. conclusion although different interlinked factors were found to affect the reflectivity of gypsum and halite, their spectra remained recognizable. the reflectivity of salt crusts varied according to changes in moisture content, and the salinity of the soil drastically reduced the reflection much more than other factors. halite occurred at high soil slope value than gypsum; however, positive correlation figure 8. ratio of the surface slope and reflectivity to other soil characteristics. table 3. principal component analyses among the studied variables. principal components pc1 pc2 pc3 pc4 pc5 eigenvalue: 2.6656 1.3282 0.892 0.7005 0.4137 percent: 44.4272 22.1362 14.8662 11.6751 6.8954 cumpercent: 44.4272 66.5633 81.4295 93.1046 100 slope –0.34024 0.24565 –0.45603 0.77205 0.14093 reflectance –0.2967 0.21914 0.8078 0.33429 -0.31568 ec –0.33737 0.55637 0.13165 -0.3669 0.65168 moisture 0.4026 –0.36501 0.34914 0.37881 0.66279 quantity 0.51005 0.47374 –0.0114 0.0839 -0.09087 table 2. descriptive statistics of the studied soil samples. parameter reflectivity (%) slope (%) ec salt quantity (g/cm2) moisture (%) minimum 25 1.32 6 1.36 3.86 maximum 45 17.55 19 7.67 11.86 mean 32.91 3.61 13.36 7.03 7.03 standard error 0.863 0.72 0.82 0.38 0.39 median 32.5 2.13 14.4 3.97 6.63 standard deviation 4.23 3.56 4.06 1.89 1.93 sample variance 17.9 13.68 16.5 3.58 3.75 g eologia c roatica howari et al.: hyperspectroscopic and microtopographic analyses of salt crust forms on arid, silty clay loam desert soils 49 between the slope and mean reflectivity of both salt crusts was reported. it was difficult to assess the order of factors controlling the reflectivity and formation of salt crusts and their alternation in the following suggesting orders, for halite: salt quantity > slope > moisture content; and for gypsum: moisture content > salt quantity > slope. the present results are encouraging for assessing the type of salt crust by estimating the ratio of slope and reflectivity to the other variables. acknowledgment the author would like to extend our thanks and appreciation to the pan american center for earth and environmental studies at utep for the technical assistance and uae space agency for funding part (data processing) of this research (z01-2016-001). special thanks for the valuable comments from dr. s. miyamoto from texas a&m university, agricultural research center at el paso. refrences araujo, s.r., wetterliud, j., dematte, j.a.m. & stenberg, b. (2014): improving the prediction performance of a large tropical vis-nir spectroscopic soil library from brazil by clustering into smaller subsets or use of data mining calibration techniques.– european journal of soil science, 65/5, p. 718. beck, r.h., robinson, b., mcfee, w.w. & peterson, j.b. (1976): spectral characteristics of soils related to the interaction of soil moisture, organic carbon, and clay content; lars inf. note 081176.– purdue university, west lafayette, indiana. ben-dor, e., irons, j.r. & epena, g.f. (1999): soil reflectance.– in: rences, a.n. (ed.): remote sensing for earth sciences: manual of remote sensing, 3 ed., vol. 3, john wiley and sons inc, usa, 111–188. briggs, m. (1996): riparian ecosystems recovery in arid lands, strategies and references.– tuscon, az: university of arizona press, 159 p. busch, d.e. & smith, s.d. (1993): effects of fire on water and salinity relations of riparian woody taxa.– oecologia, 94, 186–194. clark, r.n. (1999): spectroscopy of rocks and mnerals and principles of spectroscopy.– in: rences, a.n. (ed.): remote sensing for earth sciences: manual of remote sensing, 3 ed., vol. 3, john wiley and sons inc. usa., 1999, 3–52. condit, h.r. (1970): the spectral reflectance of american soils.– photogramm. eng., 36, 955–966. crowley, j.k. (1991): visible and near-infrared (0.4–2.5 micron) reflectance spectra of playa evaporate minerals.– journal of geophysical research, 96, 16231–16240. csillag, f., pasztore, l. & biehl, l.l (1993): spectral selection for characterization of salinity status of soils, remote sensing of the environment, 43, 231–242. drake, n.a. (1995): reflectance spectra of evaporite minerals (400–2500 nm): applications of remote sensing.– int. j. remote sensing, 16/14, 2555–2571. ehlers, e.g. (1987): optical mineralogy, vol. 1, theory and techniques, vol. 2 mineral description.– blackwell scientific publication, palo alto, calif., 158 p. everitt, j.d., escobar, d.e., gerbermann, a.h. & alanizl, m.a. (1988): detecting saline soils with video imagery.– photogramm. eng. remote sensing, 54, 1283–1287. excel (2000): microsoft corporation, redmond, washingnton, 98052, usa. el-radaideh, n., al-taani, a.a. & al khateeb, w.m. (2017) characteristics and quality of reservoir sediments, mujib dam, central jordan, as a case study.– environ monit assess, 189, 143 p. glennl e.r., tanner, s., mendez, t., kehret, d., moore, garcia, j. & valdes, c. (1998): growth rates, salts tolerance and water reuse characteristics on native and invasive riparian plants from delta of the colorado river, mexico.– journal of arid environment, 40, 281–294. howari, f.m., goodel, p.c. & miyzmoto, s. (2002): spectral properties of salt crusts formed on saline soils, environ.– qual., vol. 31, 1453–1461. howari, f.m., goodel, p.c., miyzmoto, s. & penn, b. (2000a): spectral properties of treated silty clay loam and fine sandy loam with gypsum, halite and their mixtures: remote sensing 2000, from laboratory spectroscopy to remotely sensed spectral observation. soil science society of america, corpus christi, texas. blackland research and extension center, tx. 2–27. howari, f.m., goodel, p.c., miyzmoto, s. & penn, b. (2000): spectral properties of gypsum, halite and their mixtures: fourteenth international conference and workshop on applied geologic remote sensing (an abstract), las vegas. nevada, nov. 6–8. howari, f.m., goodel, p.c., miyzmoto, s. & penn, b. (2000c) spectral reflectance characteristics of salt deposited on the soil surfaces. second earsel workshop on imaging spectroscopy, itc, the netherlands, july 11–12. proceeding on compact diskette, itc, enshide, the netherlands, 40, 1–11. hunt, g.r., salisbury, j.w. & lenhoff, c.j. (1971a): visible and near-infrared spectra of minerals and rocks. iv. sulphides and sulphates.– mod. geology, 3, 1–4. hunt, g.r., salisbury, j.w. & lenhoff, c.j. (1971b): visible and near-infrared spectra of minerals and rocks. iii. oxides and hydroxides.– mod. geololgy, 2, 195–205. hunt, g.r. (1982): spectroscopic properties of rocks and minerals.– in: carmichael, r.s. (ed.): handbook of physical properties of rocks, vol. i. crc press, boca raton, 295–385. hunt, g.r. & salisbury, j.w. (1970): visible and near infrared spectra of minerals and rocks. i. silicate minerals.– mod. geology, 1, 283–300. international soil reference & information centre (isric)(1990): world map of the status of human-induced soil degradation. united nations environmental program.– wagenngen jmp/sas, 1999. sas institute inc. cary, nc, 27513, usa. lapotre, m.g.a., ehlmann, b.l. & minson, s.e.a. (2017): probabilistic approach to remote compositional analysis of planetary surfaces.– journal of geophysical research: planets, 122, 983–1009. massoud, i. i. (1990): salinity and alkalinity as soil degradation hazards.– fao, rome. metternicht, g. & zink, a. (1997): spatial discrimination of salt and sodium affected soil surfaces.– international journal of remote sensing, 18, 2471–2486. miyamoto, s. (2000): soil resources of el paso, characteristics, distribution, and management guidelines.– texas a and m university agricultural research center at el paso, texas, usa. mougenot, b., epema, g.f. & pouget, m. (1993): remote sensing of salt affected soils.– remote sensing review, 7, 241–259. mulders, m.a. (1987): remote sensing in soil science, developments in soil science.– elsevier, amsterdam. the netherlands, 379 p. nesse, w.d. (1991): introduction to optical mineralogy, 2nd ed.– oxford university press, new york. obkuhovbk, a.i. & orlov, d.s. (1964): spectral reflectivity of the major soil groups and possibility of using diffuse reflection in soil investigation.– sov. soil sci (engl. trans), 2, 174–184.– in: ghassem, a. (ed.): theory and applications of optical remote sensing. wiley series in remote sensing, john wiley, 1989, usa, 734 p. pieters, c.m. & enhlert, p.a.j. (1993): remote geochemical analyses: elementaland mineralogical composition.– cambridge univ. press, new york. rhoadesh, r.j. & miyamoto, s. (1990): testing soils for salinity and sodicity.– in: westerman, r. (ed.): soil testing and plant analysis. asa publication series # 3, 299–336. robertson, k., milliken, r. & li, s. (2016). estimating mineral abundances of clay and gypsum mixtures using radiative transfer models applied to visible-near infrared reflectance spectra icarus, 277, 171–186. shelley, d. (1985): optical mineralogy, 2nd ed.– elsevier science publisher, new york, 321 p. soriano-disla jose, m., janik les, j., viscarra rossel raphael, a., macdinald lynne, m. & mclaughlin michael, j. (2014): the performance of visible, near-, and mid-infrared reflectance spectroscopy for prediction of soil physical, chemical, and biological properties.– applied spectroscopy reviews, 49/2, p. 139. spec-view, (1992): jet propulsion laboratory (jpl) and united states geological survey, pasadena, california, 91109, usa. stonere, e.r. & baumdardner, m.f. (1981): characteristic variation in reflectance of surface soils.– soil sci. soc. am. j., 45, 1161–1165. summer, e.m. & naidu, r. (1998): sodic soils, distribution, properties, management, and environmental consequences.– oxford university press, usa, 207 p. summer, m.e. (2000): handbook of soil science.– crc press., boca raton., usa., 418 p. tanji, k.k. (1990): the nature and extent of agricultural salinity problems.– asce manuals and reports on engineering practice, no. 71.– am. soc. civil eng., new york, 1–17. tanji, k.k., (1996): agricultural salinity assessment and management.– american society of civil engineers, new york 10017, 393 p. villarreal-fuentes, j., levresse, g., nieto-samaniego, a.f., alexandre, p. & corona-esquivel, r. (2016): geochemistry and geochronology of the sierra de gomez limestone-hosted u deposit, chihuahua: implications for distribution of rio grande rift mineral deposits in northern mexico.– ore geol. rev., 76, 19–34. wang, f., gao, j. & zha, y. (2018): hyperspectral sensing of heavy metals in soil and vegetation: feasibility and challenges.– isprs journal of photogrammetry and remote sensing, vol. 136, 73–84. wang, x., zhang, f., ding, j., kung, h.t., latif, a. & johnson, v.c. (2018): estimation of soil salt content (ssc) in the ebinur lake wetland national nature reserve (elwnnr), northwest china, based on a bootstrap-bp neural network model and optimal spectral indices.– sci total environ, 15; 615: 918–930. zhang, f., tiyip, t., ding, j., kung, h., johnson, v.c., sawut, m., tashpolat, n. & gui, d. (2014): studies on the reflectance spectral features of saline soil along the middle reaches of tarim river: a case study in xinjiang autonomous region, china.– environmental earth sciences, 69/8, p. 2743. geol. croat. 49/1 i · 79 3 figs. !o tabs. 22 pis. zagreb 1996 taxonomic review of some barremian and aptian calcareous algae (dasycladales) from the dinaric and adriatic karst regions of croatia branko sokac key words: calcareo us algae (dasycladales), bio­ strati graphy, taxonomy, lower cretaceous, dina­ ric-ad ri atic karst, c roatia. abstract selected species of the followi ng dasyclad genera, deriving fro ill barremian ,lt1d aptian depos its of the ad ri alic and dinaric karst, are elaborated: salpingoporello, acroporclla, ilcfilloporella, clypeil1(f and pralltr/olle/fa. a new genus, /jirijerel!a, is establi shed. descrip­ tions of (he following salpillgoporelfa species arc compl e ted with newly establi shed characteristic fealu res and i llust rat ed with appropri­ ate sections: salpillgoljorella il/ilehibert~ii, s. melitae, s. iiispall/ca, s . luisi, s. iiriadonasi, and s. dil/arica. in addit ion, the follow ing new spec ies are dcscribed: s. l'caiico.w, s. hera/dica, and s. po/ygol/alis. apine/fa jafre:oi. the type species of the ge nu s apillella, is considered to be a younge r synonym of salp illgoporella hispallim . acfilloporella fjodolh·a and acroporella radoicicae are commcnted upon. prowl" lonella dalli/ul"ae is ill ust rated. sel/ipo,.el/a da/matiea and likallella pejol'il:(le have been transferred to pratl/rlol/ella. because the pro­ bl emati c lialicory/le /lerae has a lso been transfe rrcd to the ge nu s prafllr/ollc/fa (with it 's inadequate diagnosis and description), a new diag nosis and more comple te description o f th is species is give n. clypeilla? solkgni is illustra ted by barremian specimens and ciypeino gigalllea n.sp. from the lower barremian of mljet is land is described. bes ide ihe type-s pecies. ririferella spiilos(i, ihe species hi therto labelled clypeilla somoli(·(/, or similidypeilla somalica, has also been trans ferred [ 0 [he new gerllls pinferella. klju cnc rijeci: vapllellacke alge (dasycladales), b io­ slrati grafija, taksonomija, donja krcda, d inaridski ­ jadranski krs, hrvalska. sazetak iz bogatog matcrijala fosi lnih vapnenackih alga (dasycl adalcs) priku pljenih u naslagama barema i apia d inarskog i jadranskog krsa obradenc su ncke vrste rodovu: sa/pillgoporella, acroporclla. aclino­ pore/hi, clypcina i prall/rio /l e lia, a usposta vlje n je rod piri/"erella . kod vee polnalih vrsta roda stilpillgoporel/a: s. i/litclllhergii, s . //ie/i­ /(le, s. hi.\·/jallica, s. hasi, s. lir1adq/w~·i i s. dil/arica, li z ilustrativne fo tografije presjeka razlici tih orjentacija izvrsene su dopune opisa i navcdene novo uocenc znacajke. opisane su nove vrste ovog roda: s. i'errucosa, s. heraldica i s. po/ygollolis. rod i vrsta apillella jt/fewi smatra se mlad im sino nim om s. hispallictl. komen[irane su vrste acrilloporella podo/i eo i acropore lla radoicicat' . od vrsta roda prar/lrlollelfa ilu strirana je p. dalli/ovae. rod u su pribrojene sel/i­ porei/o da/matica i likallelfo pejol'icae, a s obzirolll <la je osporcna fia licoryllc nerae prebacena 1i rod praf/lrlollel/a s neadekvu[nom dijagnozom i opisom, to j e dana nova dijagnoza i dopuna op isa ove vrste. uz vrs!u clypcilla? so/kalli prikazanu baremsk im primjcrc ima opisana je clypeillo gigal/rca n.sp. iz donj eg bnrema otoka mlj e lll. novom rodu phi/erei/o, liz ti psku vrslu pir!fcrcfa .wi/rusa, pribraja se i vrsta 1'. sollla/ica do sada nejasne tak sonolll skc klasifi kacije, prethodno oznncenn kao clypeil/a so/1/a/ica odnosno simi/iclypeillll somalh.·a. contents: i. introoucfion .. . ....................... ......... .................... 2 2. systematic descri ptions ................ . . ....... .. ... ............. 2 sa/pillgoporclla iiilieh/hergi (lorenz) pia in tra uth ....... 2 salpillgopo/"el/a liieliw e rado ic ic .......... ..... ........ 3 safpillgoporel/a itispollico conr ad & grabner .. .... ..... ... ..4 sa/pingopore/la \'ernu:osa n.sp .. .. . ............ 5 salpillgopo/"ella lierafdica n.sp .. .. _ ............... ...... ...... ...... ..... 8 salpillgoporel/a polygol/alis n.sp ... .. .. .... .................. ... ........... ~ sa/pillgoporella hasi conrad et al sa/pillgoporella iir/adol1a.ti conr ad ci al ....... .... ............ 13 ... .. ............... 15 s(lfpillgoporella dil/orico radole lc ......... .. .......................... . 17 pmlltrlollella nerae (dragastan el al.) bucur ....... ........ 19 prall/dollella da/lllmica (so kac & vell c:) n.comb ............. 21 prmllriollella pejol'icae (ra do icic) n.comb ........................ 23 acroporella /"{idoicicae (prat ur lon) pratu rlo n & ra doicic. . . ..... ............................ .. .... 24 clypeil/(/? so/kalli conrad & rado jc ic .. ... ... ..... .. ... .. ... ... . 25 clypeilla gigalllea n.sp ........... ....... .. .............. . aclilloporella podojica (alth) conrad ci a l ..26 .... 27 pin/ad/a 5pillosa n.gen .. n.sp ............................... ....... ... .. ... ... 28 piriferd/a somalica (con rad et al.) il .comb ...... ........ .......... 30 3. references ............................................................. .............. 31 plates i-xx ii .. ..36 inst itute of geology, saehsova 2, p.o. box 268, hr-j()(x)() zagreb, croal ia. 2 1. introduction longlasting investi ga tions of mesozoic deposit s car ri ed ou t by the author and nume rou s colleagues in the dinaric and adriatic karst regions of croatia have res ult ed, alllong othe r things, in an abundant collection of foss il material. among this, calcareous algae (oasy­ cladalcs) rank as, pe rhaps, ihe foremost const ituent of the foss il assemblages in gene ral , with regard to both thei r divers ity and abundance of specimens, in parti cu­ lar strhtigraphic hori zons. the analysis of th is rnate rial enabled the definition of precise stratigraphic positi-on and/or range for many of the me ntioned species, owing to the pos ition of algal -bearing samples in the st ratimctrically logged sec­ tion s, as well as an swering a ilumbe r of taxonomic qucs tion s owing to the abundance and good preserva­ tion of the material , whic h can be illustrated by appro­ priate sections . in the mediterranean realm , the foss il dasyc ladales have been the subject of num c rous palaeontologic and biostratigraphic inves tigations, pre­ sented in numerous pape rs by differe nt authors. how­ ever, the primary descriptions are o ft en based on scarce and/o r poorly preserved mate rial (w hi c h somet im cs shows diffcrent fealurcs and thus implying heterogene­ ity), accompanied by few and inadcquate illustrations sometimes even one section of a fragment with blurred c haracteri s tics has been lised as the basis for establish­ ing a new species o r the alleged rev is ion of an cxis ting one . such bad prac ti ce has resulted in inadeq uate knowledge about particular taxa, un sound establi shing of taxa, a ll eged c harac teri stic fea tures resu ltin g from the subjective inte rpretation of the author, unjus tified inc rease in the nu mber of ne w taxa, and frequent trans­ fe rring of individual species to anothe r genus without sound arguments ("n. com b. "). besides, several species , or groups or species, of the same genus (e.g., sa/pil/go­ parella) may show simiiarl y shaped ramifica tion s (branc hes) which can produce sec tions that may appear s imilar o r almost identical for two or three species, leadin g to co nfu sion in identifica ti on by less experi­ enced workers. thi s implies that the original descrip­ tions ofte n lack adequate illust rations; whereas many are accompani ed by too fe w characte ris tic sections, some of the sec tions illustrated arc 110t species-charac ­ te ri sti c and many belong to two or more species (t his may depend sometimes on very s li ght d ifferences in the plane, or "depth", of the section). the most obviolls e rro rs occur w he n the identifi catio n of a species is based 011 o r, at le as t, res ult s fro m it s s trati graphic positi on. an even more seriolls problem lies in the intraspec ific variation which can be more or less pro­ nounced and can affect the shape of the branches (most frequently, the shape o f the pores at their dis tal e nd), numbe r of branches per whorl , and most frequ entl y the range o r dimensions. all thi s produces the dile mma of whi ch differences should be treated as intraspeci fi c va riati ons and whi ch a re spccies-characteristic. some­ times, admilled ly, we are dealing wi th continuous geologia cro;l lica 49!j ranges or forms whose end members, howeve r, clo show clear differences. from a pragmati c point of view, proble matica l ident ificatio ns and eonrusio n of taxa have serio li s conseque nces with regard to the ir s trati ­ graphic use fulness and rel iability, though, in my opin ­ ion, these parameters s ti ll seem to stay quite firmly , at least on a local to regional scale. of course. st ratig raph­ ic ranges are always subjec t to change, but the new data should be based on indisputable identification and pre­ cise a nd well documented evidence of stratigraphi c position. ait that has bee n mentioned above represent s but a smail fraction of the unsolved questions in the study o f fossil algae, a ll of which concentrate on, or can ultimate ly be reduced to, the establi shin g of val id and unequi vocally adopted criteria for identification . perhaps the tone of thi s paper may sometimes sollnd polemic or unduly critical. my inte ntion was, howeve r, to clarify the taxonomy by comple ting the hithe rto exi­ s ting descrip ti ons of sollle taxa, to support my cla ims by unequivocal sections (therccore the somewhat larger ilum ber of illustrations a fact that was obviously miss­ ing in illany earlier pape rs), to correct some incorrect interpre tations, to describe some taxa in the manne r i consider correct, to de limit the ir s trati grnphie ranges in the dinaridi c and adriati c karst areas, and to expla in some of my reflcctions on the validity or the new taxa and the criteria of the ir establish ing and recogn it ion. 2. systematic descriptions genus sa/pingoporc/la pia in trauth, 19j8 the generic diagnosis by pia (in trauth , 1918) has been comple tcd by con rad ( 1969) and summa· rized by sc hindler & conrad ( 1994). to thi s, the followin g addition should be added: species with branched thallus, or showing a te ndency toward branc h­ ing, <:ire also included in the genus. salp;ngoporella iilllch/bergi; (lorenz, 1902) pia in trauth, 1918 pi. i, figs. 1· 13; pi. xx, pi gs. 48 , 58 selected synonym y: 1902 dip/opora !i1i;h1bergii n.sp. · lorenz. p. 52· 54, figs. 3-6 , 'i fi g. 7 191 8 sa/pingoporella l1iuehlbergii (lorenz) l1.gel1., n.comb.· pia in tra uth , p. 2 11 ·213, fig. 4a 1978 sa/pillgoporel/o mllch/berg ii (lorenz) 8ucur, p. 95, pi. 8, fig. 5 1978 sa/pillgoporel/a iiilieh/berg ii (lorenz) dragasta n, 8ucur & demeter, p. 22· 23, pi. 2, ?fig. 4 ; pi. 8, fig. i pars; pi. 9, pig. 3, non figs. 1,4, 'ifig. 2; pi. ii , fig. 4 pars 1978 so/pillgoporel/a mllchlberg ii (lorenz) con rad & pey8ernes, p. 69·83, pi. 2 , fig. 10 lobe: taxonomic review or somc b~lrrcmian and aptiall calcareou~ algae ... 1978 salpingopore//a mllehlbergii (lorenz) yellc & sokac, p. 3 19-334, pi. 2, fig. 2 1979 salpingopore/la iilllehlbergii (lorenz) pey­ bernes & conrad, p. 743 -751, pi. j, figs. 6-7 1980-1981 salpingopore//a i1lllelilbergii (lorenz) bucur, p. 55, pi. 1, figs. 7-8, non fig. 6; pi. 2, ?figs. 1-2 1984 salpingopore//a /1/llelilbergii (lorenz) luperto-sinni & masse, p. 341, pi. 38, figs. 3-4 1985 salpingopore//a mllehlbergii (lorenz) b ucur, p. 83, pi. 4, fig. 2 1989 salpingopore//a i1lllehlbergii (lorenz) dragastan, p. 13-14, pi. 5, ?fig. 5, fig. 6, non fig. 7 1989 salpingopore//a mllelilbergii (lorenz) conrad & masse, p. 283, pi. 2, fig. 6 1993 salpingopore//a mllelilbergii (lorenz) bucur, i. cociuba & m. cociuba, p. 3438, pi. 1, figs. 9,11-14 1993 salpingopore//a mllelilbergii (lorenz) sot­ ak & misik, p. 403, pi. 10, figs . 1-6 1994 salpingopore//a mllelilbergii (lorenz) bo­ drogl, bona & lobltzer, p. 233-248, pi. 1, ?fig. 8; pi. 16, non fig. 6; pi. j7, fig. 8 pars this is a frequent ly mentioned and figured species. the emended description and the designation of a neo­ type was given by conrad ( 1970). in the descrip­ tion s of thi s species the phloiophorous shape of the ramifications has been emphasized: tubular in the prox­ imal part and funnel -shaped at the d istal end. the distal widenings are supposed 1o be mutually touch ing outside the calcareous envelope. the shape of the distal wide­ ning depends, according to conrad (1970), on the h and w values; specimens with slightly flattened ramifi ­ cations, such as figured by praturlon & rado­ lcic (1967, figs. la-d,s), have also been includ ed within the specics. thc spec imens studied and illust rated in this paper (pi. 1, figs. 1-1 3), which i consider to be typical reprc­ senlatives of the species, show a comparatively long proximal tubular part of the branches, which retains about an equal diameter in both longi tudinal and trans­ vcrse sections until it attains the outer surface of the calcareou s envelope. the comparatively high h va lue between the alternately arranged whorls, as well as the small number of ramifica tions per whorls (w), gives the appearance of widely spaced ramifications in deeper tangential secti ons. the outer (dis tal ) part of the branches, where they abruptly widen, is rarely pre­ served, and where present, appears more square-shaped than rhombic. the differences with other contempora­ neous salpillgoporella species in the barremian depo­ sits appear morc visually pronounced than expected from simplified and generalized descriptions and com­ parison of individual dimensional values. among nuffi3 crous sections obtained from several localities in both the adriatic (including the islands) and dinaric karst regions, two sections have becn studied which suggest the existcnce of a branching thallus (pi. i, fig. 6). according to the observations gathered up to thc present, the first occurrence of this species in the adri­ atic and dinaridic karst regions is exceptionally and rarely assoc iated wit h campanclulla cgpuensis (de castro), the lattcr being generally considered to have a strat igraph ic range correspond ing to the upper hauteri vian and lower barremian. in this case too, s. muehlberg!i is accompanied by nulllerous dasyclads characteristic of the barremian algal assemblage. its upper limit (last occurrence) is also the first occurrence of palorbitolina lenticularis (blumenbaci-i). thus, taking into account both the position of au samples with this species in the analyzed (logged) sections and the assoc iated algal assemblage, the stratigraph ic range of s. muchlbergii in the adriatic and dinaridic karst regions is considered to correspond to the barremian. salpingoporella melitae radoicic, 1967 pi. ii, figs. 6-13; pi. iii, figs. 1-2; pi. xix, fig. 7; pi. xx, figs. 2b, 3b . selected synonymy: 1967 salpingoporella ",elitae n.sp.radoic1c, p. 121 -126, figs. 1-2, pi. 1-4 1975 salpingoporeila melitae rad01cic dra ­ gastan, p. 61, pi. 86, fig. i 1976 salpingoporella melitae r adoicic con­ rad & peybernes, p. 191, figs . 13 b, h 1978 salpingoporella melitae r adoicic dra ­ gastan, bucur & demeter, p. 23 -25, pi. 7, fig. 3; pi. 12, figs. 1-2; pi. 14, ?fig. 3. 1978 salpingopore/la melitae radoicic yelic & sokac, p. 319, pi. i, figs. 8-10 1980 1981 salpillgoporella melitae radoicic bucur, p. 53-55, pi. 1, figs. 1-5 1984 salpingoporella melitae radoicic lupe­ rto-sin ni & masse, p. 34 1, pi. 38, pigs. 2, 7-8 1987 salpingoporella melitae radoicic rado­ icic, pi. 1, fig. 6 pars; non fig. 7, fig. 8 1989 salpingoporella melitae radoicic con­ rad & masse, p. 283, pi. 2, ?fig. 12 1989 salpingoporella me/itae radoicic draga­ stan, p. 13, pi. 5, ?fig. 3, fig. 4 1992 salpingoporella me/itae radoicic manci­ nelli, p. 9, 13, pi. 4, figs. 2, 12, noll fig. 11 1993 salpillgoporella melitae radoich': bucur, i. cociuba & m. cociuba, p. 35-38, pi. 1, fig. 16 1994 salpingoporella melitae radoicic bodro­ gi, bona & lobitzer, p. 233-288, pi. 1, fig. 6, non fig. 7; pi. 17, fig. 11 4 the suffi ciently detailed original descripti on (rad­ oleic , 1967) clearly defines this species as a rather large-s ized alga, with a spacious axia l cavity and dense­ ly arranged alternating whorls of ram ifi cations. the author emphasized the funnel-shaped pores with a com­ parativel y long tubular proximal part (pi. ii , figs. 7, 13). the di s ta l part o r the ramificati ons is abruptly widened and transversally nattcllcd , i. e ., horizontally elongated, produc in g an e longated-rhombic shape (pi. fl , fig. 7; pi. lil, fig. i), deeper tan gen tial sections, culting the proximal part or the branches, show widely spaced rounded pores in alternating arrangement (whorls arc not tightly compressed) , whereas the slml ­ lower tangenti a l section s show the abrup tl y widened pores, mutually touc hing on the surface. t ypical, well­ d eve loped , spec im e ns clearly show the ir rhombic appearance in shallow tangential sec ti ons cu tting through the di stal part or the branches. the corners of the more or less e longated rhombs are clear and sharply de lineated (pi. ii , fig. 7; pi. ill, fig. i), but inwards the corners becomc 1110rc blurred and the rims more round­ ed. because this species incl udes specimens with highly va ri able dimensions (d, d), the above mentioned char­ acter isti c features should be used as the primary criteri­ on for a safe and re liable spec ies identification. howe ver, thc dis tal ends of the ramifications ean be va rioll s ly shaped and/or de rormed. bes ide the rather typica l sections (pi. iii , fi gs. 1,2), speci mens can be found that show a more o r less pronounced dive rgence in ihe distal shape of the pores (pi. 11, fig. 9), in which case thcy appear to re present an inte rm ediate form bet wcen s. !lie fila e and some othcr species or that genus (perhaps s. hasi or s. iir/adanasi). thu s we are faced with the dilemma of how much of divergence should be regarded as bei ng w ithi n the range va ri a tion of the spec ies and a lte rnati ve ly, which diffe re nces should be trea ted , taken togethe r, as sufficie nt fo r the establish­ ment of a new taxon. s. /j/c/irae occurs as the most abundant species, both s ingly and in assemblages with s. nllleh/bergii, s. ljiakol'cllsis, s. ilispanico, s. dinariccl , pratllr/onello dolli/ovae, aclilloporella podalien, c/ypeina? so/kalli, clypeilla sp. and ot her a lgal and, morc ra rely, fo ra­ miniferal species. according to our observations in the adriatic and dinari c kars t regions, its firs t occurrence co in c ides with the las t occurrence of ca /j/pane/i/lla caplicnsis de castro. the lalter species being char­ acte ri s ti c of the uppcr hauterivian lower barremian, this would the re fore correspond to the lower barremi­ an. the las t occurre nce of s. melilae is just be ll ow the firs t occurrcnce o f pa/orbilolina lelllicu/aris (blu­ menbach), as is a lso the case with s. "il/ ehlbergii. only one sample, derived from ml. ve lika kapela, con­ tain s s. melilae associa ted with p. lel/tiel/laris, which re liably defines its barremian age. geologia croatica 49! l salpillgoporella hispallica conrad & grabner , 1975 pi. v, figs. 1-8, part. figs. 9-11 se lected svnonymy: 1975 sa/pingoporella hispanica l1. sp.conr a d & grabner, p. 30-39, figs. 2-6 1979 sa/pingoporella hisponica conrad & grab­ ner peybernes & conrad, p. 946-748, pi. 2, fig. i: ?s. cf. hispanica; pi. 2, fig. 2 19801981 so/pil/gopo/'e l/o hispal/ica conrad & grabner bucur, p. 53-54, pi. 2, figs. 3-4 1986 apil/ella hispanico (conrad & grabner, 1975) n.eomb. granier, m ichaud & fo­ urcade, p. 804-806. 110t fig ured 1986 apil/el/a jajj/'ezo i n. sp. granier , m icha­ ud & fourcad e, p. 804-807, fig. 2, pi. i , figs. a-j; pi. 2 , figs. a-j 1991 sa/pingoporel/a alt. s. hisponica con rad & grabner kuss & con ra d, p. 876 , figs. 4, 14 1992 salpillgoporella itispallica conrad & grab­ ner mancinelli , p. 9,12-13, pi. 3, fi gs. 1-5 1993 sa/pil/goporella hispallica conrad & grab­ nerbodrogi , conrad & loi3itzer , p. 64-66, pi. 2, rigs. 710 1994 salpillgoporello itispanica conrad & grab­ ner bodrogi , b6na & lobltzer , pi. 6 , figs. 1-2 in their original description, conrad & grabn­ er ( 1975) emphasized the sma il number (w=4) of short , shallow calc ified ramifications, arranged in alle r­ nating consecllti ve whorls, with a calcareous ske le ton consis ti ng of thill-wa ll ed , hyaline, calcite. the recon­ st ruct ion (conrad & grabner , 1975, fi g. 7) shows the connecting pores be tween the ramifi ca tions and the axia l cavity to be s ituated in thc middl e of the proximal part orlhe ramifications, which means that the ramifications regularly swell in both upward and down­ ward directions and have a short and thinl y calcifie d partit ion be tween each and every ra mifi cation and a s li ght te rminal bulbou s swc lling. this has le d the au thors to interpret ihe di stal ends or the ramifi cation s in shallow tangential sec tions as square-shaped, which howe ver should be regarded as thc personal inte rpreta ­ tion. moreover, it was just ihis differencc that was used by granier et al. ( 1986) as the basic dille renee for es tabli shing their ncw gen us a nd species apille//a jaf­ jrezoi gra lier et a1. , in whic h the connect ing pore is shifted downward and the ramification itself is ve rtica l­ ly flatt ened at its distal end and has a hexagonal co n­ tour. the spec imens from the barremian of cres is land that are illus trated in the present pape r (pi. y, figs. 1-8) ancl labe lled salpillgopore/la itispallico do in fa c t, by sobc: taxonomic revicw of somc 13arrernian and aplian calcareous algae ... their key characters, stro ngly diverge from conrad & grabner's (1975, fig. 7) reconstruction. instead, they show the connecting pore shifted downward (pi. y, figs. 3, 6, 8, 11) and a hexagonal contour of the dis ­ tal pore openings (pi. y, fig. 2), those being the charac­ teristics that make them identical to the specimens described as apil/clla jaffrczoi. this, however, shows that recons tructions, no matter how nice they may appear (and how welcome, in certain cases, they really are), represent nothing more than the authors' interpre­ tation and thus may be misleading in certain cases. some minima l dilterences between the kimmeridgian specimens from mexico and our barremian speci mens do exist; firstly the extreme dimension values, though these values, for the most part of their ranges, do over­ lap; secondly, there is a minor differencc in the widen­ ing or the axia l cavity between the branch-bearing whorls, which is more pronounced in the kimmeridgian specimens (granier et ai., 1986, pi. i, fig. a; pi. 2, fig. b) than in some of the barremian specimens (pi. y, fig. 3). however, this fea ture is not a regular character­ istic: in some specimens it is missing and therefore can­ not be accepted as a valid criterion for species-specific differentiation. on the contrary , the above mcntioned list of identical features seems to confirm the identity bet ween the kimmeridgian specimens from mexico and the barremian specimens of the mediterranean realm , indicating that apinella jajfrezoi shou ld be con­ sidered a younger synonym of sa/pillgoporclla liispani­ ca . herewith, the latter species acquires an extended stratigraphic range. an summary, the establishment of the genus apillel­ la , based on the reduced degree of calcification and the numbe r and shape of thc ramifications bei ng broadly elongated above a short and eccentrically situated con­ necting pore in apine//a does not seem justified for the following reasons: 1) the apparently reduced degree of calcifica tion can directly depend on the more pronounced swelling of the ramifications, partieu[arly if that swelling occurs abruptly from the very base; 2) the superficial calcification may only be an artefact of preservation and a consequence of the external destruc tion of the thin partitions between the ramifi­ cations (visible in the illustrations of granier et ai., 1986, where the partitions between the ramifica­ tions sometimes appear longer and sometimes almost completely reduced, i.e. destroyed by sec­ ondary processes); 3) the reduced number of ramifications can be a direct consequence of their shape and mode of wideni ng, whether from their very base or more distally, and of the degree of transverse compression (horizontal f'lattening). there arc a number of sa/piflgoporclla species with a varying number of ramificat ions, e.g., 5-11 in s. fiiuchlbergii, 8-12 in s. af/nulata, 5-7 in s. katzcn', 5-7 in s. liasi, ctc. tn general, those salpin ­ goporella species which have transversally com5 pressed (= horizonta lly ilattened) ramifications do also have a smaller number of ramifications. there­ fore, it follows that the delimiting number of ramifi­ cations for the genera apinclla and salpingoporella would be 4 and 5, respectively. 4) the shape of the ramifications broadly elongated above the short , narrow, and eccentr ically si tu ated connecting pore is only more strongly pronounced in s . hispanica, while also present though more slight ly developed in s . katzeri. this latter species, however, was not included in the genus apinella. also, in the original description of s. katzeri there is no mention of the branches being strongly swollen upward and the connecting pore remaining at the level of the lower ramification rim (pi. x, figs. 1012). the eccent rically s ituated connecti ng pore also occurs in the genus trip/oporella and accordi ng to my personal observations is also present in palaeo­ dasycladus medilerranclls pia, which, however, does not question the generic and species-specific attribution of the mentioned forms. instead , it is an indication of the variation within a genus and, even, within a species. an conclusion, it may be said that the lack of char­ ac terist ic featu res that would unequivocally differenti­ ate apinclla from sa/pingoporclla indicates that apirlel­ la should be cons idered to be a younger synonym of sa/pingopore//a, as has already been clearly stated by bodrogi et a l. (1993). the large geographic distance between mexican and european fin ds, as well as the cons iderable difference in their stratigraphic positlon (mexico: kimmcridgian; europe: barremian), do not alone seem to justify the establishment of a new taxon (there is also the possibility of migrations , common ancestor, etc.). stratigraphic position: in spite of the largc number of samples collected from jurassic and cretaceous beds from all over the dinaric karst area in croatia, the finds of this species remain rarc. it has been unequivocally idenlified at only two localions: in the barremian a lgal assembjage on the mljet island and in barremian depo­ sits of the cres island, where it is associated with s. hasi (spec im ens illustrated in pi. v, rigs. i-ii). as a resuit of it s rare occurrence, the definitive establ ish­ ment of its stratigraphic range remains open, though the two hitherto known localities both are of barremian age. salpillgofjorella verrllcosa n.sp. pi. vi, figs. 1-15 origin of the name: the species has been named aiter the wart like protrusions on the outer surface of the calcareous envclope which mark the terminations of the distal ends of the ramifications (latin verruca = wart). type locality: island of mljet, road-cut on the road sobra babino polj e, a bou l 2 km from sobra (17'36'oo"e and 42°44'02"n, fig. i ). 6 '\:2) o rig. [ topographic map of a pari of the mljcl island. the algal­ bearing localities arc marked as follows: a) clypeillo gi,~mll('a n.sp., s(lfpingo{jort'!{(l po/ygollofis 11.sp.: h) sa/pillgoporella 1'('i"i"ii('osa 11.51'., piriferella ,lpil1osa ll.gcn., n.sp. type stratum: well-bedded , light coloured, biotur­ bated algal wt\c.:kcstoncs with casts and moulds of green algae and gastropods. the environment of sedimenta­ tion is defined as within peritidal zone, wit h sporadic cmcrsions into the vadose zone. lio!otype: slightly oblique, a lmost longitudinal, sect ion rigured in pi. vi, fig. 4, slide mg-81/8. all slides containing the material or the new species arc stored at the institute of geology. zagreb. dimensions in mm: maximum observed length (l) outer thallus diameter (d) inner thallus diameter (d) the did relationship distance between whorls (b) length of the branches (i) maximum ramification diameter (i') number of branches pcr whorl (w) inclinalion of branches «x) total range 2.04 0.38-0.72 0.20-0.32 34-59% 0.14·0.24 0 .1 2-0.20 0.06-0.10 6-8 eca 15° geologia cro:liica 49/1 ~ __ ~====~2 ____ ~3km diagnosis: sa/pillgoporel/a w ith rare, alternating, phloiophorolls ramirications with bulging (convex) out­ er surface. covered wi th a thin calcareolls sheet. description: the cylindrical calcareous envelope is composed llp of coarse-grained, blocky, light yellowish calcite. the outer surface is covered by alternating wart-like bulges, which represent the distal ends of the ramifications. the inner surface of the axial cavity is s tra ight and sharply delineated. t he axial cavity most most frequently 0.44-0.64 0.24·0.30 40-50% table 1 dimensions of salpillgopo/"ef(a l'e/tilcosa n.sp. sokac: taxonomic review of some barremian and aptian calcareous algae ... frequently comprises 40-50% of the total diameter, depending on whether it is measured at the level of the bulges or in between, where the outer surface appears slightly depressed. simple, undivided, phloiophorous branches commu­ nicate with the axial cavity by means of short and tiny connecti ng pores (channels) and broaden slightly and continuously from their very base toward their distal ends. the branches reach the surface and end in wart­ likc protrusions that are covered by thin calcareous membranes. the calcareous envelope appears to be attenuated outward, which along with the ramification, produces a star-shaped transverse section at the level of whorl s (pi. vi, fig. 14). the ramifications are directed slightly upward, at an angle of about 15°. similarities and differences: salpingoporella ver­ rucosa belongs to the group of salpingoporella species, in which the ramifications are neither 10ngitudinauy nor transversally compressed, giving in tangent ial sections a rounded pore regardless of where it is cut (i.e., in both deep and shallow tangential sections). it differs from other species of this group by the coarse-grained mosa­ ic calci te of the calcareous envelope, a very small num­ ber or ramifications per whorl, and a comparatively large distance between the whorls, the latter features giving the impress ion of pores being situated few and far between on the outer surface. the end in gs of the pores on the outer surface make bulging, wart likc pro­ trusions, which give this alga its characteristic appear­ ance. stratigra phic position: salpingoporelfa verrucosa n.sp. occurs in an interval of well-bedded fossiliferous mudstones and fossiliferous peloid and oncoidal wacke­ stones with several intercalations of intraformational, marl-cemented breccia which test ifies to repeated shal­ lowing and local emers ion (fig. 2). that interval com­ prises about 30-40 m or stra ta beneath the algal-bearing leve l and about 30 m above it, and corresponds, as a whole, to depos ition in restricted shoals with frcqucnt oscillations and excursions into very shallow subtidal and intertidal zones. these strala contain saipingo­ parella mueh/bergii (lorenz), s. aff. eemi rado~ rcrc, s. melitae rad01c1c, s. hispauica conrad & grabner, sa/pingoporella dil/ariea radolcic, salpingopore/la sp. ex gr. genevensis-hasi, acrojjorella radoic/cae praturlon, pralurlol/ella dani/ovae (radoicic), p. ncrae n.sp., piriferella spinosa n.sp., and aclil/oporc/la podolica (al ti-t), most of which occur in the same sample with s. vent/cosa n.sp. based on the above mentioned alga l assemblage, and the supcrposilional location of the sample in the higher part of the column , which has well-defined boundaries (fig. 2), the age of the s. vcrr/lcosa bearing beds at the type locality may be establ ished as upper barremian. lithologically, the entire barremian sequence is characterized by tex tural and structural features which arc. according to t1sljar (1986), typical of rhythm ic sedimentation ranging from gradua l shallowing to g~ vavl ~ ~ b -mlj81 mlj-78 mlj -73 mlj-71 mlj-65 i zom 10m om 7 2 3 • fig. 2 detailed lithofacies co l limn of the typelocality of c/ypeillo gigallfea n.sp., so/pillgoporef{o po/ygollotis n.sp., sa/pillgoporef­ fa ve/"mcosa n.sp. and pirifeu:!la spillosa n.gcn., n.sp. legend (facies types after tisljar & velie, 1991): i ) f-acies of suprat ida l and/or temporary emersions: soft pebble conglomer­ ates and cll1crsion breccias facics type k-l; 2) facies of inter­ tidal 10 shallow subtidal limestones: llh st!"omatoliles, fenestral mudslones to pellelal wackestones facies type k-2: 3) facies of lagoons and restricted shoals : mudstone/wackestone and onko­ lites facies type k-3 : 4) facies of late diagenetic dolomites fac ies type k-5: mlj -63 mlj -83: sample designation. restricted shoal or from the subtidal to the lower inter­ tidal and the vadose zone, respectively. in vertical sequence, th is is manifested by the transi tion from a homogeneous micrite/pelmicritc into fenestral micrite/ pelmicrite with eroded upper bedding planes and/or vadose features, and sometimes even tidal channels. , sa/pillgoporella heraldica n.sp. pi. vti, figs. 118 origin of the name: in tangentia l sections, th is alga shows an alte rnation of dark and light squares, reminis­ cent of the croatian coal of arms. t ype locality: island of korcuia , road-cut loward prizba, about 50 m from the cross-road in bma village ( 16'5 1 '30"e and 42°54 '29"n, fig. 3). type stratum: well -bedded brown al gal -pe lo idal g ra in stone. the sample was collected during a fi e ld reconnaissance campaign and had been taken at ran­ dom. t herefore no detailed lithological analysis can be given. however, acco rding to the gene ral geologica l his to ry o f the a rea, the age can be in fe rred as be ing transiti ona l barrem ian-aptian, and the environment as a peri tida l-tidal bar. holot ypc: t angel11ial section figured in pi. vii , fig. 5, slide br-3 a/28. all slides containing the new species afc kept at the institute of geology, zagreb. diagnosis: a sa lpillgoporella with large ax ial cav i­ ty and fu nnel-shaped , alternatin g ramifi ca tions, whi ch o o fig.3 topographic illap o ra part or the korcula tsland . locality with salfjillgofjordla heraldica n.sp. and pmrur!onella lieme (dra ­ ga$tan ci al.. t978) is marked with aitow. geologia croalica 49/1 in tangential sec tions appear square-shaped , producing the characteristic chequered appearance. description: a comparat ively small d asyc lad alga wilh a cyl indrical, sometimes gently c ulved lhall us. the calcarcous cnve lope, similar to many othe r spec ies of this genus, is composed up of ye llow ish, crys talline cal­ cile. the axial cavity is borde red by a smooth surface, pe rforated by comparati vely large pores at the begin­ ning of the ramifi cations . the oul e r surface also appears to be smooth, but the oute r termina tions of the ramifications arc possibly slightly convex . the ram if ications are simpl e , undivided , arranged into regular alternating whorls. they are orientated per­ pendicul ar to the axial cavily and appear sho rt , which may be a consequence of a destroyed oute r surfacc. the ram ificatio ns s lart with a compara tively w ide pore in re lation to ihe lolai size and widen regularly and uni­ fo rmly toward the dis tal e nd (pi. vii , figs. 1618), re ta ining at rhe same time a square contour, regardless of the depth of thc tangent ial section (pi. vii, figs. 3, 56, 10). the alternation in shall ow tangent ia l sections of approxi mate ly equal dark squares o r the pores and light , calci tic squares of the ske leton produces the charac tc rkorc~ c> o ~ ~o ____ -===== ____ -"3km sokai:: taxonomic review of some barremian and apfian calcareolls algae ... dimensions in mm: outcr diameter (d) inncr diameter (d) tile did relationship (di d) distance between consecut ive whorl s (h) lcngth of rami f ica tions (i) diametcr of ramificat ions (p) number of ramifications per whorl (w) total range 0.35-0.68 0.25-0.39 50-70% 0.04-0.05 0.09-0.1 2 0.05-0.09 11-14 islic chessboard palte rn (or the croatian coat of amls). this appearance is s trengthened by the fac t that the da rk squares of the porcs a lmost touch onc anothe r at thei r corncrs, which emphasizes both the diagonal and the quadrangul ar pattern (pi. vll , ri gs. 3-5). this fact was the reason for choosing a tangent ial section as the holotype. similarities and differences: salpingoporella heraldicci n.sp. is clearly distinguished from other salp­ ingoporella species, i.c. from those in which the distal parts of the ramificat ions a rc e ithe r longitudinally or transversely compressed. if the dis tal ends of the pores arc compressed, they produce a hexago nal , rhombic, rec tangular, or more rare ly, quadrangul ar (square) pat ­ tern on thc outer surface. in those species in which the pores in cortica l secti ons appear square-shaped , the pores in deeper tangential sections appear more or less rounded , as d is tinc t fro m s. heraldica, in which the pores re tai n the ir square shape regardless o f the whethe r we arc deal ing wi th shallower or deepe r tan­ gential sections. by its general dimensions, s. heraldica belongs to the grou p of rathe r small sa lpingoporcllae. by its s ize (dimensions), the di d re lat ionship , and the num ber of branches per whorl , s. heraldica comes quite c lose, or even overlaps, with the corresponding values f"o r s. dina rica. however, it clearly diffe rs from the lat­ ter by the coarse-grained calci te in the calcareous enve­ lope, square po re open ing in the tan gcnti al sec tion s, pronounced diagonal paltern in pore arrangement, etc. other species from the sa me group, i.e. s. is/riana, s. johnsoni, s. selli i e tc., arc charac te ri zed by phloio­ phorous ramifications ihal do not show e ithe r longitudi­ na l o r transverse compression. the diffe rences with regard to these species concern the d imensions, number and shape of branches, e tc. (see table 3). concerning the question of how far the dimensional va lues (measured e lements) and thei r proportions should be taken int o conside ration as signifi cant crite­ ria , the original data shou ld be considered first, provid­ ed the spec ies is recogni zed as va lid. late r data often relate to incorrec t identifica tions and are often addi tion­ al ly biased because of the small num ber of measured sections (whose spec ific, and sometimes even generic, allribution is frequent ly problematical), which renders any statistical inte rpre tation questionable. stratigraphic position: salpingopore/la heraldica n.sp. has been found in a random sample , which makes most frequently 0.54-0.64 0.34-0.39 50-60% 0.05 9 tab le 2 dimensions of salf1ill~{)fjo/"(!lla heraldica n. sp . a more precise definiti on o f its s trati graphi c pos ition and environmental sell ing imposs ible. the sampl e in qucst ion shows some characte ri sti c features which incli ­ cate a perit ida l-t idal bar e nvironillent , as s imilar fea­ tures occur in samples collected from logged sections, in the same or st rati g raphica ll y close hori zons, in the study area. the same sample a lso contains the follow­ ing mi c rofoss ils: triplopore //a bacilli/onl/is sokac (the same sample is also the " type specimen"), 1'. mar­ sicollo praturlon, t. iirogieliiformis con rad & peyb ernes, and praturlol1ella i/erae n. sp. the occurrence of rare palorbitolina lenticularis (blu­ menbach) in the immedi ately overlying deposi ts indicates a terminal barremian or, possibly, basa l apt­ ian age. salpillgoporella polygollalis n.sp. pi. iii , figs. 310; pi. iv, figs. 1-17 1994 sa/pingoporel/a nr/adanosi conrad, pey­ bernes & r adoicic bodrogl b6na & lobitzer, pi. 17, fig. 4. orj~in of the name: the name of the species is der ived from the irregular, po lygona l pores as they appear in shallow tangential sections. type locality: island of mljcl, road-clit al the sabra babino polje road, aboul 2. 15 kill before sabra, 150 iii away from the locality of s. i'errllcosa (17°36'00"e and 42°44'02"n, fig. i). type slralum: well-bedded, lighl-coloured , biotur­ bated alga l wackestones with casts and moulds of dasy­ c lad al gae and gas tropods (fig. 2) . bioturbations arc fill ed wit h pell o ida l grai ns tone and small benthi c fo raminife ra. the sedi menta ry e nvironment may be defined as shallow subtida l. hololype: obliquc seclion figured in pi. iii , fi g. 3, slide mlj.63/68. all slides 0 1' thi s specics arc kepi al ihe institule of geology, zagreb. in 101al, about 25 dif­ ferently oriented sections have been examined. dia~nosis: a salpingoporella wi th large, a lte rna t­ ing. ramifications, that are funne l-shaped from the vely base, di sta lly thickened and hori zontall y flatt ened, which show an irregular, rhombic-hexagonal to c llipti ­ cally polygonal paltern , with an indication 0 1" di s tal splillin g. the calcareo us wall is composed o/" ve ry coarse-grain ed, heavily weathered and recrysta lli zed calcite. 0; species 0 d did h p p pro~;on.1 p ,li,!al a w salpingoporeua adriatica (gus ic, 1966) 1.36-2.62 0.26-0.50 0.30-0.35 0.50-2.20 0.20-0.40 20-22 s. a/j/lli!ata carozzl, 1953 0.30-0.64 0.10-0.25 0.15-0.20 8-20 s.ambica elliot, 1968 0.31-0.73 0.21 -0.47 55-66% 8-10 s. arllmael/sis okla, 1995 2.1~2.8 1.61.8 0.20-0.5 0.30-0.5 0.20-0.27 20 s.? atlantica (johnson, 1968) 0.71 0.36-0.375 0.050-0.075 0.025-0.017 0.042-0.055 45 0 s. biokoviellsis sokac & velie, 1979 0.55 -0.74 0.12-0.22 0.20-0.34 • 0.44-0.74 0.10-0.25 16-476% 0.18-0.32 0.22-0.25 0.10-0.32 7-r s. bl/cllri dragastan, 1989 0.95-1.30 0.25 0.050 0.20 0.10 to-20" 14-16 s. cemi (rado ](:: ic , 1968) 1.8-1.6 0.44-0.52 0.38-0.48 0.16-0.24 20-25 s. circcassa farinacc i & rado ic [c, 1991 0.165-0.38 0.06-0.14 0.20-0.5 0.30-0.5 0.20-0.27 20 s. croatica sokac, 1992 0.34-0.92 0.14-0.38 0. 12-0.16 0.08 -0.12 8-14 frequently 0.42-0.52 0.24-0.28 0.12-0.14 0.08-0.10 12 s. dinorica rado icic, 1959 0.24-0.56 0.128-0.40 0.048 810(7) , 0.07 -0.48 0.05-0.38 4 1-47% o.oj-0.06 0.04 0.08-0.12 7-12 s. enayi bern ier, 1984 0.867-0.950 0.325 -0.425 38-44% 0.25 -0.275 0.10-0. 12 30? s. etalfolli bernier, 1984 0.325 -0.450 0. 1-0.137 28-30% 0 .125-0. 150 0.05-0.062 70-800 20? s.? cxilis (dragastan, 1971) 0.6-0.8 0.2-0.3 0.025 -0.030 s.jlucgcli dragastan, 1978 0.54-1.20 0.25-0.56 0.080-0.25 0.025 -0.030 0.090-0.15 1012 =mcgaporella pucgcli (dragast an) 1989 0.601. 10 0.30-0.56 ? 0.025-0.030 0.10-0.15 12 s. gencvcl1sis (conrad, 1969) 0.6-1.0 0.27-05 i 45 -51 % 0.09-0.11 6? 7-9 s. grudii (rado icic, 1963) 0 .128-0.48 0.064-0.240 0 .032-0.1 20 12-20 s. hasi conrad et ai., 1976 0.21.12 0.1 -0.72 0 .06-0. 13 5-7 , 0.34-0 .82 0.20-0.54 4 1-77% 0.04-0.08 0.12-0.14 0.20-0.24 5-7 s. heraldica n.sp. 0.35-0.68 0.25 -0.39 50-70% 0.04-0.05 0.09-0.12 0 .05-0.09 11 14 co n 0 c s. hispa/jica conrad & grabner, 1975 0.25 -0.46 0.1 6-0.36 66-77% 0. 15-0.26 4 n~ , 0.24-0.44 0.17 -0.30 64-84% 0.12-0.14 0 .14-0.28 4-5 n a s. humilis (bystr icky, 1967) 0.633-1. 183 0.283-0.750 42-68% ~ 0.033 -0.050 0.033-0.058 7-12 g ~ '" ~ s. istriano (gus ic, 1966) 0.25 -0.74 0.14-0.41 0.03 -0_04 0_06-0.105 0.012-0.05 16-28 ~ s.jolmsolli(dragastan, [971) 0_20-0.31 0.10-0.15 0_033-0_045 0 .05-0_07 0.02-0.04 14-20 ;:;' 0 q s. km::eri conrad & rado ici(::, 1978 0_26-0_80 0.10-0.40 0.08-0_16 5-7 , o· " s. me/flae radole,,:, 1967 0 0.48-1.255 0.32-0.960 161-24 < ('i" * 0_64-1.68 0.36-1.14 50-68% 0.05-0.08 0.17 -0.34 0.19-0.28 14-20 , ., s.liiilol'gnol'iri radoic1c, 1978 ~ 0.070-0.240 0.035-0.1 12 0.040-0 .075 9·15 9 , 0 5· 11 " s. liiuehlhergii (lorenz, 1902) 0.2 -0.85 0.1-0.3 0.07 -0.18 ~ , 0.28-0.86 0.10-0.54 26-62% 0.08-0.1 3 0.10-0.20 0.10-0. 18 7-8 ::;" 0 s.pirilliac karas & rad01cic. 1991 ?0.180 0.064-0.160 0.064-0.090 10-1 4 " 1l 0. 240-0.530 > frequen tl y 0.350-0.400 " ;:;-, s. potn/fills; bueur , 1985 1.10-2.300.11-0.28 10-24% 0.22-0.28 0.56-1.00 0.040-0_078 0_16-0.31 25-35° 7-9 q it " s. polygollalis n.sp. 0.82 -1 .48 0.35-0.74 44-55% 0_14-0.19 0.22-0.35 0_06-0_09 0. 14-0.34 10-12 ~ s. po/saki sokac & jelaska, 1991 > 0.48-0.72 0.12-0.24 25-30% 0_08-0_11 0.20-0.28 0. 12-0.24 20° 9-12 rf 0s. pratllriolli (dragasta:-.j, 1971) 1.2-4.0 0.6-1.6 0.25 -0.90 0.07 -0.030 20-40 s. pygmaea (pi a, 1925) 0.43-0_72 0_17-0.26 0.02 0_09 16-19 s. rob/isla sokac, 1993 0.77 1.44 0.20-0.48 27·30% 0.12-0.24 0.28-0.48 0.15-0.28 811 frequently 0_86-1.1 0 0.24-0.30 0. 15-0.20 0.30-0.40 0.20-0.24 8-9 s. se//ii (crescent!, [959) 0.24-0.44 0.06-0.16 0.018 0.016-0.02 25-27 s. steil/hauseri conrad e t a [. , [973 0.26-0.33 35-44% 0.08-0_1 1 45° 7-8 s. sturi (bystricky, 1967) 1.611-3.444 0.888-2.222 50-67& 2.27-4.49 0.055 -0 . 166 167-32? s . tosaensis (yabe & toyama, 1949) 0.71 0 .41 0 .05 0 .025 50 s. wrgida (radoi c ](:, 1965) 0 .57-2.1 0.22-0.72 0.064-0_ 13 0.19-0.64 0_032-0_080 0_09-0_19 12-24 s. iirladal1axi conrad ct. <11., 1977 0.65 -1.1 4 0_17-0.62 33-73% 0_015-0_13 4-8 * 0.20-0.72 0_10-0.38 30-60% 0_08-0_10 0_11 -0.28 0.14-0.24 5-76 s. /lbaiydhi rado ic u:, 1979 0.24-0.65 0.08-0.32 0_050-0_096 0.q40-0.090 8-14 s. verticil/ala (sokac & nik ler, 1973) 0.45 1. 18 0_2 1-0.56 0.04-0.105 0.15-0.44 0_02-0.05 0.05-0_12 22-30 s. )'c/t/lco.m n.sp. 0.38-0.72 0.20-0.32 34-59% 0.14-0.24 0.12-0.20 0.06-0_10 6-8 table 3 comparison of the dimens ion s of genus sa/pil/goport:!la species. * complemented by own data. 12 geologia croatica 49/1 dimensions in mm: outer di,unctcr (d) inner diameter (d) the did relationship distance between whorls (h) length of the ramifications (i) proximal diameter of the ramifications (ppm) distal diameter of the ramifications (pt/is) number of ramificlltiotls per whorl (w) 0.82t ,48 0 .35-0.74 44-55% 0.14-0.19 0.22-0.35 0.06-0.09 o. t4-0.34 1012 table 4 dimensions of safpillgoporella polygonalis n.sp. description: the massive calcareous skeleton of the cylindrical thallus of the new species is composed up of light grey, very coarse-grained, and variously rec rystallized calcite. the outer surface of the calcare­ olis envelope is always damaged, partly destroyed or dissolved, and subsequently recrystallized. that the wall was originally comparatively th ick is indicated by rare ly preserved, outwardly projecting, thin partitions between the distal ends of the ramifications (pi. lit, fig. 3; pi. iv, figs. 2, ii, 13, 16-17). axial cavity mea­ sured in the few most complete specimens occupies only about 30-35% of the 10la l diameter, while more often il appears to be about 50% due to the secondary destruction of the wall. it is delimited by a smooth plane, which in section appears as a clear and sharp reg­ ular line (pi. ill, figs. 6, 9). in some sect ions, however, the inne r surface may be more or less destroyed, too (pi. hi, r:igs. 8, 10), as indicated by the appearance of the larger pores of the ramifications. simple large (massive) ramifications arc arranged alternately in the consecutive whorls. the general shape of the branches is irregular and variable. stal1ing from a smaller or larger connecting pore, they slightly widen in the firs t half of their length, after which they abruptly swell (pi. iii, figs. 3, 6; pi. iv, figs. 6, 10), producing a funne lor bowl-shaped distal part (pi. iv, figs. 14-16). tn some specimens, the distal swelling is equally well vi s ible in both longitudinal and equatorial sect ions. however, more often the ramifications afe more or less flattened and elongated horizontally (i .e., by vertical compression; pi. iii , figs. 4, 7, 10), which gives the characteristic irregular and variable pattern in shallow tangential sections. the shape of the distal opening of the pores varies from approximately hexagonal-rhom ­ bic (pl.lil , fig. 3) to elliptical-oval (pi. tit, figs. 4, jo). in the latter case, the slight tendency towards division of the stretched parts of the primary ramificat ions may be noticeable. the question of whether the ramifica­ tions actually divide distally, as suggested by some sec­ tions (pi. tit, fig. 4; pi. iv, figs. 3, 5) , must remain open, for the time being. at their very end the branches are closed by a dome-shaped, thin, probably calcareous membrane, as suggested in a few sections (pi. iv , fig. 16) in which thin , mutually separated partitions of the adjacent ramifications are prescrvcd, which probably do not touch at the ends. the branches arc perpendicular or subperpendicular to the main stem, in some specimens being slightly directed upwards. the value of d is probably somewhat larger, because the outer surface was partly destroyed in all the sect ions observed. in some sections (p i. iii, figs. 4, 7) small hem i­ spherical recesses in the distal parts of the ramifi ca­ tions' calcareous envelope can be seen. these arc simi­ lar to, but less well pronounced then those observed in s. genevensis in which this feature was supposed to be caused by the imprint of slightly calcified cysts. in s. po/ygollalis , however, this supposition can neither be confirmed nor definitely disproved, though the imprint of slightly calcified cysts into a calcareous wall seem, in this casc at least, unlikely. unequivocal remains of even slightly calcified cysts have not been recognized, however. similarities and differences: sa/pillgoporel/a fjolygonalis n.sp. can be, in general , ascribed to that group of the sa/pillgoporella species in which the rami­ fications at their distal ends are horizontally flattened, regardless of what shape they eventually assume hexagonal, rhombic, quadrangular, or, as in this case, polygonal. the new spec ies is most similar to s. melitae, which, indeed, does show a broad variation range, from typical forms (pi. it , figs. 613; pi. ill, figs. 1-2) to the such forms that, as the tangential sec­ lions cutting through their calcareous walls become progressively deeper, gradually begin to show features intermediate to some other species, e.g. s. hasi or s. gel/evensis. therefore the new species appears most similar to the above mentioned species in the deepest tangent ial sections (i.e. those cutting the calcareous envelope in its most internal part) , where the pores of all the species concerned appear similar, regarding both their arrangement and density. going outwards, the dif­ fere nces between those species and s. polygonalis become progressively more and more pronounced, being most clearly expressed in cort ical (i.e., shallow­ est) tangential sections cu lling through the extreme dis ­ tal pa rt of the ramifications, which in s. hasi and s. gellevensis have a quadrangular, in s. urladanasi a more or less deformed quadrangular shape (pi. ix, figs. 2, 4-5; pi. x, figs. 3-4, 6), and in s. biokovellsis a square shape, whereas in s. melitae the pores appear clearly rhombic and horizontally (transversally) riatsokac: taxonomic review of some barremian :lj1d aptian calcareous algae ... tened. in s. po/ygoj/afis, however, the entrance pores of thc branches have a larger diameter than in s. rnelifae and the branches irregularly widen di stally, which makes them somewhat similar to those in s. genevellsis, but with differently shaped distal ends. in s. hasi the entrance pore is followed by a very short channel, which is, in turn, foll owed by a bowl-shaped widening, whereas in s. polygollaiis n.sp . the swe lling of the branches is irregular, sometimcs even more pronounced (but still uneven) in the distal half of their length. salpi­ iigoporel/a polygonalis clearly differs from s. katzeri, in which the bra nches also swell very rapidly, often being more swollen toward the upper side (pi. x, figs. 10-1 2), with thin partitions between the branches and the more or less pronounced hexagonal to rhombic pat­ tern al the d istal ends. in s. hispanica, the skeleton is much weakly calcified, the number of branches per whorl is smaller, and the branches also have a more or less pronounced rhombic or hexagonal shape at their ends. tn s. dillarica, the fibrous calcite, consi derably smaller dimensions, the characte ristic arrangement of tiny pores in proximal (deeper) tangential sections, and rhombic or completely flattened pores at their distal ends make clear differences to s. po/ygonalis. the dif­ ferences to numerous other species of this genus, in which thc distal ends of the pores are compressed, i. e. flattened vertica ll y, or the branches widen regularly toward thcir distal ends, giving the marc or less round­ ed pores at the outer surface, arc clear and need not be discussed at length . stratigraphic position: salpillgoporci/a polygo­ ilalis n.sp. has been found in a sample containing a rich algal assemb lage, consisting of numerous salpingo­ porci/a l7iclifac, s. l11ueijlhergii, intermed iat e forms between s. melirae and s. hasi, and less numerous s. liispanica, cfypcil/a? so/kalli, prafl/rlol/ciia danifovae, p. pejovicae, and numerous unidentified dasyclad frag­ ments. the algae arc accompanied by the foraminifera call/panelillla capucnsis (de castro) , mayllcina hl/lgariea haug et a1., vercorsella searsel/ai (de castro), and olhers. about 20 m above thi s sample, in a continuolls sequence, sa/pingopore/la biokovellsis and s. /lr/adanasi have been found . the abovc men ­ tioned dasyclad assemblage and the position of the algal-bearing sample within the stratigraph ic column at the type-locality suggest an early barremian age of s. po/ygonalis. though the above mcntioned foraminiferal species occur more frequently in the upper hauteriv­ ian, they also range into the lowcr barrcmian and thus do not contradict the proposed early barremian age. sa/pillguporella hasi conrad, radorcic & rey,1976 pi. 11, figs. i ~5; pi. vjjj, fi gs. i ~ i 0 selected synonymy: 1976 sa/pillgopore//a hasi n.sp.conrad, rado~ icic & rey, p. 99~ i 04, fig. 2, pi. i , figs. 1-10 13 ? i 986 sa/pingopore//a aff. hispanica conrad & grabner ~ radoicic, pl. 5, fig. i ?1991 sa/pillgopore//a hasi conrad, radotcic & rey kuss & conrad, p. 876, fig. 4/17 1992 sa/pingapore//a hasi conrad, radotcic & rey mancinelli, p. 9, i i i 2, pi. 3, ?fig. 15, non fig. 16 1994 sa/pingopore//a hasi conrad, radoicic & rey bodrogi, bona & lobitzer, p. 233-243, pi. 17, fig. 2 ? j 994 sa/pillgopore//a hasi conrad, radoicic & rey schindler & conrad, p. 8 i, pi. 6, fig. 14 diagnosis: dasyclad alga with cy lindri cal thallus and with phloiophorous branches which are, after a short connecting channel, uniformly and clearly bowj­ shaped (widened) from their very base. at their distal ends the branches are mutually compressed and hori ­ zontally ilaltened, producing a regular pattern of rectan­ gu lar, horizontally elongated, pores. calcareous parti­ tions between the neighbouring branches as well as betwecn the branches of two consecutive whorls, are rather thi ck proximally and taper distally, passing into thin walls which, in some sections, appear as spines. salpingoporel/a hasi conrad et al. was originally described from the upper albian and middle cenoman­ ian of kosovo, serbia, and from portugal on the basis of several, rather atypica l, poorly preserved sections and some heavily recrystallized fragments, which, when scrupu lo us ly compared with each other, show some differences. this suggests that the descrip ti on includes material belonging to different forms, or, alter­ nati vely, that the species is characterized by the pro­ nounced variability of some of it s characteristic fca­ tures. this is perhaps thc reason that this species is sel­ dom mentioned and even less frequently illustrated. its age has been most frequently restricted to thc albian­ cenomanian. the inadequately defined diffcrcnces between the strongly similar features of the related s. gencvensis s. figsi s. ur/adallasi species, lead to fre­ quent misident ifications in which barremian specimens are mostly identificd as s. genevensis or sometimes s. hispanico (radoicic, 1986, pt. v, fig. i) or just related to s. hasi (conrad & peybernes , 1976, fig. 13 ci , e) and cenomanian species are without rcser­ vations assigned to s. hasi. in the original description of s. hasi (conrad et al., 1976) , the authors mention the possibility of the consecutive whorls not always being in mutual contact but , instead , the incomple te calcification between the whorls produces a more or less deeply incised wcdge­ shaped dcpression. this feature is regarded as being species-specific. to my mind, however, this feature is doubtful, i f present at all (i.e. in somc sections it seems to be either lacking, or unobservab le; e.g. conrad et at., 1976, pt. 1, figs. 4, s, 7 iransverse, slightl y oblique section), in others, express ly mentioned, sec14 lions il is unclear (op. eil. , fig. 2, pi. i , figs. 1,6, 10), and even in the reconstructions (op. cil , fig . i) it is not c learly defined. therefore as this feat ure is nol men ­ tioned in the d iagnos is but only in the ciescription, the above mentio ned di agnosis of thi s pape r essentially agrees with the original one . however, des pite the ques tionable value of this feature, the validity of s. hasi as an independent species is beyond question. the randomly collected sample rc\ from barremi ­ an deposit s or the e rcs island yielded numerou s, well­ preserved sections that , when compared wi th some of ihe publ ished ma te rial of s. hasi (conrad e t ai. , 1976, pi. i) and despite some new ly d iscovered mor­ pholog ic details, can be unequi vocall y assigned to s. /ws i. the new ly d iscovered charac te ris tic are poss ibly the result o f be ller prese rvation of thi s mate ria l and, as such, are inadequate for the establi shment o f" a new tax­ on. they do however, make possibl e minor additions to the description o f s. hasi in order to better differentiate s. /wsi from s. gene\lensis and s. iir /adanasi, which, in some sections, may indeed appear very similar to be almost ind is tinguishable from s. /wsi. the compara tively la rge, horizo nta lly fl attened , ramifications in s. hasi show the following specific fea­ ture, visible in tran sverse secti ons: foll owin g a short connecting pore, or channel (exceptionally the channels ent e ring the axial cavity can be sli ghtl y lon ger), the ram ifi cations abruptly and unifollnly widen, forming a bow lshaped (pi. ii , figs. 2 -4) o r funn el-shaped (pi. viil , figs. 8, 10) swell ing toward the exte ri or and at the same time rctaining the ir original shape, with no signi f­ ican t deformations (pi. viii , figs. 2-3). the transvcrse­ ly cut branches (i. e ., in longitudinal and/or tangential section s) fully corres pond to the reconstruc tion givcn by conra d c t al. ( 1977, fig . 4, sec ti on aa ') for s. ifr/adall(fsi . the calca reous walls between the ramifica­ tions of ihe same whorl are th ick onl y in thei r proximal pa rts, but d ue 10 the abrupt swelling of the ram ifica­ tions, the wall s soon became very thin partitions (pi. viit , f igs. 7, 9), whi ch in beller preserved spec imens appear as spines (pi. vii i, fig. 7). thi s is never obse ­ rved in s. gellel'eflsis or s. iir/adal/osi, and this is also the main diagnostic d ifference from s. gel/evensis : in s. /wsi the ramifica tions widen abruptly and uni follllly in the hori zontal pl ane with thinl y ca lc ined pa rt itions between the ir d iswl ends, whereas in s. gellcvclisis the ramifications arc more robust, more irregul ar and with a la rger co nn ectin g po re, but arc al so hori zontally nat~ lened . tr we compare some previously publi shed sec­ tions of s. gel/el'el/ sis (e.g., conrad, 1969, figs. 1-9; dr agasta n, 1989, pi. 6, fi gs. 1-6) with the trans­ verse oblique and long itudinal sections o f s. //(is i in ihis s tudy (pi. 11 , fi gs. 1-5; pi. viii , figs. 110), the above mentioned diffe rences become c lear enough to justify the validity of s. hasi . in tangential sec ti ons, however, the diffe rences are noi so well identifiable and therefore such sections cannot be used for spec ieslevel id cnti fi~ cation betwee n s . /w si and s. gcl/e ve nsis . the differ­ ences with s. iir/adanasi , in wh ich the branches, in the ir geologi:l croatica 4911 proximal pan, also often appear very simi lar, or som e­ tim es even identical, to those of s. hasi , will be di s­ cussed with s. iirladal/asi. in connection with s. hasi , le t us brielly di sc li ss the re lationship between s. has; and s. carpalliica dra­ gastan (1969), with reference to some partial simi­ la rities in longitudinal section s be tween the two species . this should be done in spile of the fac t that s. carparhica probabl y should be considered in valid o r, at least, doubtful, being es tabli shed 011 poorly preserved and heavily recrystalli zed mate rial. conrad ( 1970) firs t mentioned that the spcc ime ns fi gured by dra ­ gastan (1969, pi. i , figs, 1-6) probably be long to s. /11l/ell/bergii (lore_ z), which was accepted by bas ­ so ullet e t al. ( 1978). cert a in sect ion s f igured by dragastan (1 969, pi. i , ri gs. 1-2 and possibl y fig. 4 ) poss ibly do belong to s . i1il1ehlberg ii , wh ereas th e sections in pi. 1, figs. 3, 5-6 arc inadequate for correc t identifi cation owing to poor prescrvation and heavy recrys tallization. for th is reason and because fi g. 2 was designated as the holotype by dragas tan, il is clear that s . carparlj ica cannot be acccptcd as a va lid spec ies. despite ih is, s. carpalhica is continuously mclllioned in rumani an papers. drag ast an ( 1975, p. 62, pi. 8 1, r ig. 3 and pi. 82, figs . i , 3) reconsidered s. carpat/lica and introduced two secti ons from the sam e slide as hypotypes . however, no new data were given because the fi gured sections consist o f full y recrys ta llized spcci­ mens that do not allow greate r insight int o species-spe­ cific features, which should have fac ili tated the identifi ­ cation o f the new spec ies. this a lso applics to !<ll er illu strati ons figured by draga stan ct 01. ( j978, pi. 8, fig. 2) and dragastan (197 8, fig. 21'; pi. 4, fi g. 9), res pectively. in dragastan ( 1978), th e re is a contradi cti on betwecn a fig ured sec tion (pi. 4, fig. 9), whi ch shows horizontall y compressed and riatt ened branches, and the reco nstruc tion (p. 11 2, f ig. 20 in wh ieh the branches are shown as be ing compressed lat­ e rall y ( i.e., elongated along the growth ax is o f ihalus) . the renewed description by dragastan ( 1989, p. 1415) gives no suppor! ror the validity of thi s species. the illustrated specimcns (pi. 5 , fi gs . 8l3) inc lude a great dcal of the already published mate ria l o f problem­ alical va lue. inc lud ing the ho]otype (pi. 5, r ig. 9 = pi. i , fi g. 2 io drag astan, 1969), whi ch co nr a d (1970) a lready identified as belong ing to s. f1/ uelilbergii an opinion with which the <l ulhor fully agrees. as thi s is the only transve rse secti on of s. cmpalli ica whi ch uncquivoca lly shows 5 ramifi cations in a whorl , the s tatement of s. carpar/jic(f hav in g 4 (5) branches pe r who rl (dragast an, 1969, 1989) al so appears inva lid. the remaining sections (dragastan, 1989, pi. 5, figs. i o~ 12) arc too poorly preserved for adequate comparison, part icularl y wit h the section fi gured in pi. 5, fi g. 13, which belon gs to an unidentifi ed form , but difrerent from that (or those) fi gured in pi. 5, fi gs. 1012. according to all that has been said above particu­ larl y with regard to the incorrectly dcsignated hololype (drag astan , 1969, pi. i , fi g. 6 = dr agastan , sokai": taxonomil: review of some l3arrerniilll aile! aptian calcarcou~ algnc .. 1989, pi. 5, fig. 8) the question remains which char­ acteristics arc relevant for distinguishing s. carpathica from other closely related and/or similar species. in conclusion, it may be said that s. carpalhica docs not seem to fulfil the requirements for being accepted as a valid species. more generally, the ever increas ing uncritical acccptance of new species or new combina­ tions, which are not adcqua tely documented, disturbs and practically (though not formally) invalidates regu­ lar taxonomy and leads to confusing and overburdened synonymy. of course, mi stakes are normal in any activ­ ity, including research, and in future research they are normally corrected. however, the problem arises when the alleged correcti on of mistakes is carried out on the same (inadequate) material, without new discoveries, and we should ask ou rselves the following question: which cri teria were used by the author in the original description and which in a later revision. therefore, as aforementioned and in order to avoid future confusion, it is strongly suggested and recommended that the establishing of a new taxon, or the revision of an exist­ ing one, of fossil dasycladajcs should be accompanied not only by illustration of the iype specimen but also of several, variously oriented, sect ions which should clear­ ly show the essential distinguishing features of the new taxons and, thus, complement the information obtained from th e type spec imen (or section, respectively). in this way, the subjective, often specu lative, interpreta­ lion of the au thor should be successfully eliminated. salpillgoporeua llrladallasi conrad, peybernes & radoicrc, 1977 pi. ix, figs. 1-13; pi. x, r igs . j-9 selected synonvmv: 1977 sa/pillgopore/la ifr/adallasi n.sp. conrad, peybernes & radoicic , p. 73-82, pi. i , figs. 1-7 1979 salpij/goporel/a urladaj/asi conrad, pey ­ bernes & radoicrc pe ybernes & conrad, p. 746-748, pi. 2, fig. 3 1986 apillclla llrladallasi (conrad, peybernes & radoicic) n.comb. granier, micha­ ud & fourcade, p. 801 -807 1989 /-iellsollella urladallasi n.comb.(conrad pey­ bernes & radoicic) masse, p. 281 1993 salpillgoporclla urladallasi conrad, pey­ bernes & radoicic bodrogl , con­ rad & lobitzer, p. 66-67, pi. 3, r ig. i 1994 salpillgoporclla urladallasi conrad, pey­ bernes & radoicic bodrogi, bona & lobltzer, p. 233-248, pi. 10, fig. 8; pi. 17, non fig. 4 from the original description of this species (con­ rad et ai. , 1977), the following characteri sti cs con­ tai ned in the diagnosi s should be emphasized: phloio­ phorous ramifications arranged in dense whorl s, trallsversa ll y compressed, giving a honeycomb-like pattern, communicate with the axial cavity th rough narrow, round pore. calcareous partitions between the branches in a whorl are bent toward the periphery in the same direction , but in ailernat ing directions in consecutive whorls. distal swelling of the branches is interpreted as resulting from the imprin ts of cysts. the calcareous envelope is bu il t of spath ic calcite which extends to the axial cavity, which is lined by a thin dark layer coill ­ posed of small, radially arranged crystal s . in the description, the opposite direction of the inclination or partitions in the adjacent whorls is mentioned , and emph asized in the reconstruction (conrad et ai., 1977, fig. 4c), though it is not clearly vis ible in the holotypc (op. cit., pi. i, fig. i). in the description, there is also the fo llowing statement: the calcareous envelope fills the enti re space between the ramifications, though a specimen from spain is mentioned, in which the cnvelopes of the branches do not touch at their ends. however, regardless of what is stated in the diagnosis, the reconstruction presented with s. hasi conrad et al. (1976, fig. 1) and s. lfrladallasi conrad el al. (1977, fig. 4) show a remarkable similari ty in their lon­ gitudinal sections, whereas the transverse sect ions arc too simplified (schemati c), being obviously based on one set of transverse sections in slides whereas another set, different from the first set, have been neglected, c.g . the reconstruction of the transverse sect ion of s. hasi (conrad et ai., 1976, fig. 4) seellls to be based on the transverse section figured in pi. i, fi g. 2, where­ as another transverse section , which g ives a different picture (pi. 1, fig . 7) seems to be neglected; however, it is sim ilar to the section a-a' in the reconstruction or s. 1i1'iadallasi (conrad ct ai., 1977, rig. 4). however, the above mentioned transverse section (conrad et ai., 1976, pi. 1, fig. 2) possibly belongs to s. melitae radoicic. nevertheless, in spite of considerablc sim­ ilarities between the two species and frequent dilemmas concerning their identification, the val idity of the two spec ies is confirmed by the available material, where both species are abundantly represented and lheir dif­ fere nces become evident. numerous, well-preserved sections ascribed to s. hasi (pi. ii , figs . 1-5; pi. iii , figs. 1-10) and s. iiriadanasi, respectively (pi. ix, figs. 1-13; pl x, figs . 1-9) make possible the visualisation and definition of some features essential ror their dis­ crimination , which were not mentioned in the respec­ tive original descriptions. the caleareous envelope of s. u/"iadanasi, in con­ trast to that of s. hasi, is built of coarse-grained, yel­ lowi sh calcite, identical in colour as that observed in s. dinarica (these two species are associated in the materi­ al deriving from ml. dinara and thus can be directly compared). in s. urladanasi, however, th e texture of calcite is clearly blocky, i.e. mosaic-like, whereas in s. dinarica it is rad ial -fibrous. as already stated in the original diagnosis (conrad ct ai., 1977), some speci­ mens of s. urladanasi may show a very thin, sometimes somewh at darker layer lining the axial cavity (p i. ix, 16 figs . i, 3). in present material it is d ifficull to tell whether that layer is composed of mosaic-like or radial crys tals. this feat ure has already been the subject of discussion (conrad & v arol, 1990; simmons et ai. , 199 1) and was also mentioned by bodrogi ct al. (i993). such peculiarities in the structure of the skele­ ton of s. urladanasi may, among other th ings, serve as additional distin gui shing features for separati ng thi s species from s. hasi 0 11 the one hand and from s. dinar­ iea on the othe r. the origin of this feature, however, remains open for further investigation. the outer surface is covered with protrusions of ramifications wi th their own envelopes extending from thc middle of their length to the distal end (pi. ix , figs. 10, 1213; pi. x, figs. 2, 3 pars,s). thi s is the reason for the occurrence of wedge-like incisions in the skele­ ton and mutuall y unconnected, deformed quadrangular patterns in superficial tangen tial (con ical) sections resulting from individual, mutually separatcd ramifica­ tions from the same whorl or from adjacent whorls (pi. ix, fi gs . 11 13). these features are ment ioned by conrad et a!. (1976) as being characteri stic o f s. hasi, but they could not be observed in the avail able materi al, nor do they seem to be visible in the original illustrations. furthermore, the available material seems to exclude the presence of such features in s. hasi (pi. vlil , figs. 2-3, 6a). ahernatively, in s. urladanasi the separate calcareous envelopes of adjacent branches clearly show the wedge-shaped intrusion s between the branches that somet im es penetrate deep into the prox i­ mal part of the skeleton (pi. ix, figs. 12-13). in cases when the envelopes in s. urladanasi are in mutual con­ tact, the thickness of the partitions between the ram ifi­ cations doubles (pi. ix, figs. 2-4; pi. x, figs . 4 pars, 6), which is not the case in s. hasi. the fu sed envelopes disappear deeper with in the calcit ic mass between the proximal part of the ramifications (pi. ix, figs. 2, 7-8), and thus the difference between s. hasi and s. urla­ dallasi also disappears. in s. lirladanasi, the horizontal­ ly flattened branches may be deformed dista lly to vari­ ous extents, which can be seen in transverse and tan­ gential sec tions. thus, in transverse sections, the branches may be abruptly and uniformly swollen, form­ ing a bowl-shape widening following the short and nar­ row pore (channel), similar to s. hasi (pi. x, figs. 8-9), or they may be irregularly swollen with one side more inflated than the other (pi. ix, fig. ii pars; pi. x, fig. ia), or they may be fu nnel-shaped, with gradual widening. some times, in spec imens with irregularly swollen ramifications, the channels that connect the ramifications with the axial cavity are directed obliq ue­ ly to the ax ial cavity (in the horizontal plane, i.e. in transverse section), i.e. they are not perpendicular to the inner surface (pi. x, fig. 8). a particularly pronounced deformation of the branches, emphasized in the original description (conrad et. a/., 1977) as a primary species-spec ific characteristic, concerns the shape of their distal ends in tangential sections. this shape in s. urlaclanasi can vary from a comparatively regular recgcologi~ croalica 49/1 tang le (pi. ix, fig. 5) to a rectang le squeezed in the middle like a bow-tic (pi. ix, fig. 4 ), sometimes with more strongly stre tched corners on one side, remi nis­ cent of the longitudinal section of a femur (pi. ix, fig. 6; pi. x, fig. 4). the part itions between the branches of the same whorl may be vertical to subvertical (pi. ix, fig. 5) in less deformed branches, or oblique, inclined to the same side. this can also be the case in the adja­ cent whorls, or else, as has been stated in the original description, the inclination can be reversed in adjacent whorls (pi. x, fig. 4 pars). the intensity of deformation of the ramification' s distal ends varies from individual \0 individual and even in the same individual. the vary­ in g exten t of deformation of the ram ifi cati ons in s. urladanasi proves it to be of secondary origin and thus neither this feature can not always be used as absolutely reliable [or speci fi c determination. therefore, it is not considered likely that ihe distal swellings of ram ifica­ tions are due to imprints of cysts, or rather, there are no indications for such an interpretation. regardless of the original descriptions of s. hasi and s. urladanasi and the accom panyin g reconstruc­ tions, all data based on the abundant avai lable material suggest that the difference s between the two spec ies can be specified as follows: in s. hasi the ramifications are more or less regular and in transverse sections (= in hori zontal plane), after a shon channel, abruptly and regularly widen into a bowl or funnel-like shape. the calcitic mass between the prox imal part of the ramifica­ tions within a whorl abruptly thins di stally, givi ng, in better preserved specimens, the appearance of spines. such dis tally th in partitions make it impossible to accommodate uncalcified ho ll ow spaces (recesses) between the ramifications and thus prevent the individ­ ualization of rami fications at their outer ends. o n the contrary, in s. urlaclanasi the calcit.ic mass between the ramifications of the same whorl also becomes thinner, but halfway out (or in the outer third) , and sometimes even earli er, it sp lits into two separate ca lcareous envelopes of the dista lly individualized branches. as a consequence of this , there are uncalcified wedge­ shaped recesses which som etimes may reach deeply into the proximal part of the skeleton (pi. ix, figs. 1213). in s. hasi, the part itions between the ramifications of the same whorl and of the adjacent whorls are regu­ lar and in the outer tangential section hal f as thick as in s. urladanasi, in whi ch they arc often separated from each other with deep uncalcified , wedge-shaped inser­ tions. the partitions between the ramifications in s. hasi being this thin, make it impossible for the ramifi­ cations lo bulge out on the outer surface. therefore the ramifications were probably covered by an uncalcified membrane, in contrast to s. lirladanasi in which the protruding ramifi cations are evidently covered wit h a calcareous envelope composed of the same calcite as the proximal part of the skeleton (pi. x, fig. 2). stratigraphic position: in spite of the fact that unequivocal finds of s. urladanasi as defined in this paper are not very numerous, it s total ra nge in the sokiic: taxonomic review of somc barremian and aptian calcareous algae ... region or the dinaric karst in croatia can now be reli­ ably detennined due to its lowest (oldest) occurrence on the island of mljet and its highest (youngest) occur­ rence on mt. dinara. on mljet, s. urladanasi has been found associated with salpingoporel/a biokovcnsis, in a sample situated 20 m above the rich algal assemblage also containing campanellll/a capuensis (de cas ­ tro), which indicatcs the lower barremian age (see the description of clypeina gigantea). on the other hand, on mt. dinara , the sample with s. urladal/asi is situated 25 m above the assemblage consisting of salp­ ingoporella dinarica radoicic, acropore//a radoici­ cae praturlon, orbitolina (mesorbitolina) milluta douglass, sabal/dia minllla (hofker), nezzazata simp/ex omara, deharina hahoujlercnsis four­ cade, and vercorse//a scarsel/ai (de castro) (foraminiferal identifications by i. vellc). about 15 m above the bed with s. lirladanasi, the first orbifo/ina (mesorbilo/illa) lexalla (romer) occur, and pass upward into a typical albian microfossil assemblage. therefore the total range of s. urladanasi, in lhe region of the dinaric and adriatic karst , can be defined, for the time being, as barremian-aptian. salpillgoporella dillarica radoicic 1959 pi. xi, figs. 1-10; pi. xii , figs. 1-13; pi. xlll, figs. 1-8; pi. xiv, figs. 1-9 selected svnonymy: 1959 sa/pil/gopore//o dil/arica n.sp. radoicic, p. 33-42, pi. 3-5 1960 hellsol/e/la cylindrica n.gen., n.sp. elliot, p. 229-230, pi. 8, fig. i 1982 hel/sol/e//a luperto-s inni & masse, p. 870, figs. 12 ct-e 1983 sa/pillgoporel/a dinarica radoicic con­ rad, peybernes & masse, p. 93-94, pi. 6, figs. 6 pars, 12 pars 1984 /-/ellsollel/a sp. (gr. dinarica) luperto-sin­ ni & masse, p. 340, pi. 33, figs. 7-8 1985 /-iensol/el/a dinarica (radoicic) masse, p. 719 1987 salpingoporella dillarica radoicic rado­ lcic, p. 73-79, pi. i , figs. 5 pars, 6 pars 1989 salpillgopore//a dinarica radoicic dra­ gastan, p. 13, pi. 5, figs. 1-2. 1989 hensone//a dinarica (radoicic) masse, p. 281, not figured 1989 hellsonel/a dil/arica (radoicic) masse & luperto-sinni, p. 32, not figured 1990 sa/pingoporel/o dillarico radoicic , 1959 (alias /-iel/sonella cylindrica elliott, 1960, a lias hensollclla dinarica) conrad & v arol, p. 206, fig. 9 1991 sa/pingoporel/a dinarica radoicic kuss & conrad, p. 874 876, fig. 4.15 17 1991 hellsonel/o dinarica (radoicic) sim­ mons, emery & pickard, p. 955-959, fig. j a-c 1992 sa/pingoporel/a dinorica radoicic mancinelli, p. 9, 13, pl. i, fig. 10 1993 /-iellsollelia gr. dinarica (radoicic) luper­ to-sinni & masse, p. 300, pi. 4, figs. 8-10 1994 sa/pingoporel/a dinarica radoicic , 1959 schindler & conrad, p. 77, pi. 2, figs. 9ii; pi. 4, fig. 16 this is a very well-known species, which occurs frequently and abundantly in the areas surrounding the mediterranean and the middle east (i.e. the southern tethyan margin). it was originally described as a small alga with cylindrical thallus, rather broad axial cavity, and comparatively thin walls (radoicic, 1959). the simple, undivided, phloiophorolls ramifications are characteristically arranged into a quincunx pattern, ancl are horizontally flattened at the distal ends, where the porcs assume an elongated-rhombic patlem. a species­ specific characteri stic is that the calcarcous envelope consists of radial-fibrous calcite and is lined on the inside by a thin dark layer of microcrystallinc calcite. these two characterist ic features were usee! by elliott ( 1960) for the establishment of his new genus and species hensonella cylindrica (problcmatica, annelida?). later, however, elliott (1968) consid­ ered it to be a younger synonym of sa/pingopore/la dinarica. since then, many authors have discllssed the species (e.g., luperto-sinnj & masse, 1982, 1984; conrad & v arol, 1990; simmons et al., 1991; schindler & conrad, 1994), mainly due to the two peculiar features mentioned above, which were co nsidered uncharacteristic of the dasycladales. sim­ mons et al. (1991) have summarized the previous dis­ cll ssions ancl, basing their conclusions on the results obtaincd by cathodoluminiscence and microprobe analysis, have concluded that the calcareous envelope of s. dinarica was composed of primary low-mg calcite and thalthis was its original structure, no mailer how highly unusual this was for the dasyclads and how dif­ ferent from the other salpingoporclla spccies. for this reason they ascribed this species to hensonella , as has previously becn done by luperto-sinni & masse (1982, 1984). the truth is, that almost all sections of this form show a more or less pronounced radial­ fibrous calcitic wall structure. this structure is in gener­ al, better displayed in specimens in which the pores of th e ramificat ion s arc only slightly visible (see, for instance, elliott, 1960, pi. 8, fig. i; schindler & conrad, 1994, pi. 2, figs . 91 i and the sections in the present paper, e.g., pi. xi, fig. i). however, this is not a rulc without exception, though the reverse is also often true (p i. xi, figs. 4-6; pi. xii, figs. 6-7). in the majority of the observed spccimens, thc axial cavity and the surrounding space are filled with coarse-grained blocky calcite cement or the surrounding sediment (pi. xi, figs. 6, 8, 10; pi. xii, fig. 1). 18 however, in spite of the facl ih al the wa ll s of s. dinaric."o arc almost always composed or radial-fibrous, yellowish calcite, the re arc a few exceptions to thi s ru le, too. conside r, for instance, sections fi gured in pl. xii, fi gs. 11 , 13, in which the fibrou s calcite is partly or ful ­ ly replaced by microcrystalline ca lcite identical 10 tha t of the surrounding sediment. the oute r and inner sur­ faces of the ca lcareous envelope a rc marked by a thi n layer of yellowi sh ca lc ite. thi s phenomenon should probably be conside red as a consequence and result of diagene tic processes . a lso, the re arc a few sections in which the radial fibrou s ca lc ite g rows upo n the thin , dark , microcrys ta lli ne layer ins ide the axia l cav ity, fill ­ ing it pa rt ly (pi. xtl , figs. 1, 5) or wholly (pi. xli , figs. 8 pars, \9). the same rad ia l-fibrous calc ite also occurs, though more rare ly, on the oule r surface. in such cases, too, it is separated from the calcareou s wall itself by a thin dark layer probably of microcryst,:liline calcite (p i. xli , figs. 5, 10). the developmcnt of thi s radial -fibrou s calcite , which is certa inly of secondary or igin and syn­ ch ronous wi th the blocky cal ci te ceme nt in the ax ial cavi ty, may be thought of as a conseque nce of o ver­ growth ( i.e . syntax ia l rim cement ) . this indicates that during diage nes is the axia l cav it y may be partly or wholly fill ed with either (a) surrounding li me mud (pi. xi, fig. 7), (b) secondary blocky calcite cement , or (e), more rare ly, radial -fibrou s calcite (p i. xiii , ri gs. 5, 910). evenlually, both within the ax ial cavity and on the ex te rnal s ur face o f the ske le ton , synchronously and in the sam e e nvironme nt , blocky (granula r) and radia l­ fi brous calc ite deve lops, and thus the q ues tio n ari ses why in somc cases there is an ove rgrowth (if indeed it is), and in others there is not. the thin dark inne r layer has been noti ceci by all worke rs who have dea lt with thi s spec ies, beg inning wit h the original descr ip tion by r adoi c ic: (1959). elllolt ( 1968) s tressed lhe pri mary organic na lurc of thi s layer and s im mons e t a l. ( 1991 ) w lled ihal it could be interpre tcd as a primary organic membrane, about 0.012-0.018 mm thick, that lines the calcareous e nve lope on the inside. c on rad & varol (l990) a lso consi der this layer in s. dillaric{( to be of primary o ri gi n. in the available material (p i. xil , rigs. 1-2, 5 , lo; pi. x][] , figs. 1-4), two types of dark mi eroerys­ tallinc laye r can be di s tinguis hed , which di ffe r as a result of the time and origi n of the ir growth . t he firs t type may be more o r less clearly vi s ible but is a lways prcscnt , lining the inne r surface of the calcareous wa ll and being in imm ed iate contact with the radial -fibrous ca lc ite of the wal l. the primary origin of this laye r and its function during the life of the al ga, as assumed by conrad & varol ( 1990: " in vivo"), is confirmed by the ex iste nce o f the pores in the layer, wh ich are vis­ ible in tangential sections (pi. xiij , figs. 1-2). the sec­ ond type inc ludes the ve ry dark m ic rocrys talline layer that may be unevenly developed (i.e. be ing of variolls thickness) and whi le lacking in some specimens, in olh­ ers it may be more pronounced than the firs t type . this layer origi nated during ca rl y diagenesis, probab ly as a geologi" croalic:, 49/1 result of biological ac tivity of mi crobial organi sm s or by accretion of organic muc us on the a lga l s kel e tal rema ins (thi s is the third or the fourth possibdit y men­ tioned by conrad & varol, 1990) . it can develop both on the outside and the ins ide of thc ca lcareous e nve lope; in the firs t case it occurs as a th ill layer (of va riable th ickness) eit he r wholl y ' ·enc rusti ng" the skeleta l remain , or only in part ; it is usuall y onl y deve l­ oped on some specimens wi thin a sample . the second case, i.c. when thi s laye r is developed on the ins ide of the calcareous envelope, is shown in pi. xii , figs. [ -2, 5 , 10. sometimes the ou te r laye r visib ly dest roys the outer surface of the calcareous e nvelope and pene trates deeply into the rad ia l-fibrous calci te, reaching, in some cases, ihe ax ial cav ity (pi. xii , fig. 2). it may be c learly and sharply de limited toward the surrou nding sedime nt (pi. xii, figs. 1-2,5), or it may pass gradually i11l0 the surrounding scci iment , [arming a darkened zone around the a lga l ske le lon (pi. xl , figs. 8, 10). when developed in the ax ia l cavi ty, it can partly cover the pr imary da rk microcrystalline layer (pi. x ii, fig. 10). lt is more fre­ que nt ly developed ins ide the ax ial cav ity , e ithe r as an unin te rrupted zone (pi. xi i, fig. i) or fragme ntaril y (pi. xli , fig. 5), if the ax ial cav ity has already bee n partly fill ed, in which case it int errupts the growth of the sec­ ond gene ration calcite ceille nt within the axia l cav ily (pi. xif , fig. 5) , be it rad ia lfi brous or b locky. in thi s case, ihc narrow zone o r the primary dark mi c rocrys­ ta ll ine laye r is sharply de lineatcd as a reg ular oval (depe ndi ng on the o bl iqu ity of the section), which is li gh ter than the irregular seconda ry m icroc ryst a ll ine zo ne and darkc r than th e li ght calc it e of the ske le ton and the first generation or the secondary calci te cement (radia lfibrous or blocky), which always fill s the centra l part o f the ax ial cavity (pi. x ii, fig. l). amo ng num erous samples contain ing s. dinarica, the re a rc on ly two samples (bo th aptian in age, one from the dugi otok is land and the other fro m the mali losinj is land) , thai , in addi ti o n 10 typical spec im ens, a lso contain a few sections which show the tende ncy of a branching th allu s and , eve n more rare ly, some sec­ ti ons in whi ch the branching of the tha llus is c lear ly deve loped, s im ilarly to some recent gene ra ( v a let, 1968). t he tende ncy of the branching tha llus is di s­ played by longi tudina l spli tt ing of the axial cav ity and can be seen in transverse and obliq ue sections wit h more or less pronounced extensions of the inner surface into a fold di rccted toward the centre of the ax ial cav ity. the initia l formation of th is fold appears, in some sec­ tions, like a denticle (pi. xiv, fi g. 5). if ihe ex te nsion of the fo ld is illore pronounced and proceeds frol11 both oppos ing s ides, it leads to a part ia l (pi. xl!! , f ig. 6) or comple te splitting of the axial cavi ty illlo two para lle l (p i. xi ii , figs . 6-7) or s lightly divergent (pi. xiv, figs. 3, 6-7) tubular cavities which are, still , connected by a common calcareous enve lope (pi. xiv , figs. 1,7); that is, the indepcndent branches a re not ye t full y form ed. precise ly thi s fact led to the supposit ion of two spec i­ mens tightly pressed toge ther, in which the ca lcareous 'obi;: taxonomic review of some lbrrcmi:m and aptian calcareou.'; algae ... ~nve lopcs along the contac t were supposed to be partly )j" completely dissolved. howcver, this is refu tcd by thc ~x i s t e ncc of secti on s tha t show the s in g le calcareous ~nvelope, in which the charac teri stic arrangement of the jo res (well visi ble in tangential sec tions) was re tained . md which, by its mere d iamete r, eanllot accommodate . wo individ uals (pi. x lii , fig. 3; pi. xiv, fig. 8). the longi tudinal sec tion fi gured in pi. x iii , fig. 5, clearl y , hows the branc hing of an initially tubul ar tha i us, whi ch continu es to grow with two slightly divergen t, ind e pe ndcn t branc hes, eac h wit h it s own ca lcare ous :;nve lopc. in sp ite of two unique features, the thallus of th is alga is composed of low-mg calc ite (stmmons e t a i. , 199 1) and the re is a thin dark inne r layer of m icroclys­ ta lline ca lcite (w hi c h is al so rare in othe r dasyclad spec ies), 1 am , for the time being, not inclined to chan ge it s taxonomic c lass ification , i. c. 10 remove it from the genus safpij/gopo/'clfa. if we accept the taxo­ nom ic c mcndation , thi s would mean givi ng grea te r in1po rlancc to a new paramete r the primary calciti c mineralogy of the skele to n w hose ph ys io logic rol e and biolog ic s ignificance are far from clear, and rcjcc t­ ing, in turn , the clear morphologic c rit e ria that have se rved us well in the hitherto es tablished class ification of the dasyc lad algae (shape and arrangement or ramifi­ ca ti ons, etc.). these morpholog ic: criteria are striking ly s imilar to those in othe r sa/pillgoporcl/a spec ies . besides, the re is the new ly di scovered featu re of the branching thallus, obviously not so nue in this species, and tent atively indi ca ted even in the type spec ies , s. /iii/eh/bergii (pi. i , fig . 6). the stratigraphic ran ge, geographi cal di stribution, and e nvi ronm ental p refere nces of this species have been frcquently commented upon, as is ev idenced by an exceptionally abundant synonymy (bassou llet et ai., 1978, and th is pape r). tn the dinaric and adri atic karst areas it occurs in va rious fac ies types of the shal­ low wate r carbonates , frequen tl y assoc iated wi th other ca lcareous al gae, benthic foraminifera (both " large" and "sm a ll "), corals, bivalves, etc . therefore , co ntra ry to what has been stated by s immons et al. (199 1), in my opinion it cannot bc cons idered as be ing charac teri stic o f particular k inds of e nvironme nts. it occurs mos t abundant ly in mi c riti c limes tones of protected uppe r barrem ian and apt ian lagoons. its oldest occurrence in inves tigated area is in the valanginian of wes tern istria (pi. xl , fig. 1), where in a continuous lithostratigraphic succession , it occ urs not far above the first occurrences of epifllosfopora cekic i radoicic and trip/opo/'el/a lieocollliell sis radoic i<:. which arc cons ide red to be mos t common in the lower and middl e valang inian. thus, the to tal s tratigraphic range of s. dinoric(l in the adr iatic and dinarid ic kars t areas can be inte rpre ted as from the middle (or more likely, upper) valanginian , up to and including the albian. its lower boundary thus coincides with the data g iven by conr ad & v arol ( 1990) and schindler & conrad (1994). 19 t here is s till anothe r phe nome non whi ch see ms worth me ntioning in connec ti on w ith this alga: the comparativc ly frequen t occurrence of eharaeeans asso­ ciated with s. dillarica or, very abu nd antly, in laye rs immediate ly be low or above the beds wi th s. dinarica . in western is lria , in thc m iddle-uppe r valanginian , s . dinarico is associated wi th a peculiar type of characcan (pi. x iv, figs. 10-13), w hi ch has so rar not been observed in the younger (barremian-aptian) deposits 01" that are a. maybe such characean s ca n be caut ioll s ly used as an indi cation of the valang inian age of the oth­ erwi se ba rre n deposits , at leas t in a geographi ca ll y rcstric ted area. genus pralllrlollella barattolo, 1978 praillriollella lierae (dra gastan, bucur & demeter, 1978) bueur, 1993 pi. xv, fi gs. 119 ? 1978 ha licorylle nerae n. sp. dragasta n, bueu r & demeter, p. 28, pi. 12, figs. 5-6 1993 prawrlonella lierae (dr agast an, i3 ueu r & demeter) n.com b. bueur, p. 103, pi. 8, fig. i, ?figs . 212 1993 uk,," ell,,? sp. mass e, p. 3 16, pi. 2, fi g. 8 1993 i'r{///frlonell" dallilovae (radoicic) sotak & misik, p. 403 , pi. 6, fig. 8 this species, first described as holicoryne /ierae by dragasta n e l al. (1978) was later transfe rred to prawrlonella by bueur ( 1993). in the original description or 1-lalicoryl/e li erae (dragastan et ai., 1978), the a uthors described oval -ellipsoid bodies, g iv­ ing the ir d imensions (length , w idth , number and diame­ ter of cysts), whic h represcn ted an inadequate descrip­ li on of these frag me nts . the re ro re mis ik ( 1987) con­ s ide re d thei r assignment to ha/icoryne as doubtful. among alilhe sections figured by bueur (1993, pi. 8, figs. 112), only one sec tion of a segme nt (op.e it. , pi. 8, fig. 1) is c lear enough, where as other sections (o p. cil , pi. 8, f igs. 212) cannot be ide ntifi ed with certainly with ihe section figured on his pi. 8, fig. 1. moreover, the diffe re nce is also v is ible whe n the dime ns io ns of" cys ts in dragastan et al. ( 1978) are compared w ith the va lues of "p" (both o n di s ta l and prox im al e nd s) given by bueur ( 1993) . in spite o r some visual s imi­ larity be tween the sec tions fi g ured by bueur ( 1993, pi. 8, fi gs . 312) a nd those in the present paper (pi. xv, figs. 1-19) , only a prob le mati c al compari son is poss ible and the present author is not. convinced that we are deali ng wi th the same foss il form . the question is, among othe r things, how can 95 % of the sections fi g­ ured by bueur ( 1993) represenl tangential (?) sections th rough isolated segments, whereas almost 100% of section s studied here (pi. xv , figs. 119) show lhe more or less complete a lgal skeleton , regard less of the ori entation. however, independent of these considera­ tions, the assignment of halicoryne j/erae (dragas 20 c is, or s light ly below the whorts, appears s ligh tly nar­ rowe r. p. ncrae is al so distinctly smalle r than p. jol'­ dallica k uss & conrad, [rom which il also di ffers by the shape of the ramification s and the number of rows of ramifications within a ring. p. ha!lll1ll1r/ai (radoi c ic), which has rcccmly been ass igned 10 fa/­ solikallella (schlagintwe it, 1990) and was or ig i­ nal ly desc ribed [1'0111 heav ily recrysta llized mate rial (radoic ic, 1975 , pi s. 1-2), shows a s imilar heighl of calc ified rings (segments), according 10 kuss & con­ rad ( 199 1), this howe ver being th e sale similarit y. the c1i1lcrcncc is most ev ident in the di d values, whic h arc distinc tl y larger in p. lierac. a great visual si mi la rity which, in some sec tions, amount s to an impression of total likeness, ex is ts between p . lierae and carbon iferous windsopore/la radiala mamet & rudloff. comparison belwccn the illu s tra ted sections of w. radiata cmamet & rudloff, 1972, pi. 3, figs. 18-25) and p. lierae (pi. xv , fi gs . 1j 9) reveals an id enl ieal ske letal form, arrangeme nl of ramifica tions wit hi n the calc ified rings and thc ir direction 0 1" growth dive rg ing bot h upward and downward from the hori zonta l plane, a nd al so s light widcnin g of the cent ral cavity at the leve ls of whorls, all these features being essentia lly the same as in p. /lerae. the dillcrcnces concern the much small er dim ens ions of w. radiota and the pattern of ram ifica­ tions, which, accord ing to mamet & ru dloff ( j972), are grouped into bundles of four issui ng from a common basis , or constitu te a bunch of a ramified pri­ mary branch, rcspecl ivcly (sec mami2t & rudlof'f', 1972, fi g. 3). thi s last s tatement, however, remains specu lative, w ith rega rd to the author 's assertion that the calci fi cation of the ramification's e nvelope occurs no sooner than from the ir departure point, and thus the exis tence of common departure point , i.e. the primary ramifica tion , is made doubtful. thi s doubt is further s tre ngt he ned by secti ons fi gured by mame't & r udloff' ( 1972, pi. 3, fig. 18, fig. 22: lefl sidc o f ihc uppe r ring, pi g. 23: le ft s ide of the lower ring), whe re one gets the impression o f rami fications issu ing sepa­ rately from the axial cavity , s imilarly as can be seen in some sections of p. salcmitana fi gu red by baratto­ lo (1978, e .g. pi. 5, figs. 10, 12, 14; pi. 7, figs. 1,3, 4, e tc.). however, being uncertain does not necessarily mean tha t the inte rpre ta ti on of maill et and rudloff is impossible; there fore the object ivisati on of this poss ible and s ignificant d iffe re nce be tween windsoporella and prallf l"loj/clla should be a matter for furt her resea rch on the type-species of wi/ld.mporel!a. if, on the other hand the main characte ristics of windsoporella are proven to be ide ntical with those of the tale r established prahi/·­ iollel/a, the quest ion of the validi ty of the genus pratl/l ·­ /onella ar ises. however, the large time span separating two taxa with identical c haracteristic fea tures, suggests agrccmcnl wilh koci-iansky -devide & gusic (1971 ) who mentioned severa l ins tances of the repeated occurre nces of s imilar and/or (almost) iden tical fo rms and other c haracteristics in the course o f evolution of geologia cro;llica 49/1 the dasycl ada[es without implying the ir generic unity , which would a lso seem a li ke ly ex planation fo r the lvilldsoporellalpratlirlollella s itua tion, im plying tha t the two genera do not belong to the same li neage. thus prall/rlol/ella would remain a va lid genus. stratigraphic position: the remains of this a lga have been found in a randomly collected sample during geologica l reconnaissance of the central part of korcula island. therefore it is impossible to assess its full strati­ graph ic posit ion and its age can only be determi ned on the bas is of the accompanying mic ro fossils, which include trip/opore//a bacililormis sokac, t. marsi­ coi/o praturlon , sa/pillgoporel/o hera/dim n.sp. , and cylilldroporella ivallovici (sokac) . in addition , th e algal-bearing sam ple lies immediate ly (probab [y about 2-3 m) be low the first find s of pa/orbitolillll icllticlflaris (bl um en bach), sugges ting that the stratigraphic posit ion o f the algal-bearing sample is top barrem ian or maybe lower aptian. pmturlonella dallllatica (so k ac & velle, 1978) n.co mb. 1978 sel/iporel/a da/lilatico n.s p. sokac & velic, p. 23 l -234, pis. 6-9. 1982 ukallel/a? dani/ovae r adoic ic (p .parlc anel all. dalli/ovae) conrad , p. 2. cons ide r ing its generic attribution and taxonomic valid it y, ihis species was conside red by conrad (1982) to be a you nger synonym o /" prali.lr/olle /lo dani/ovo e (radoicic) or, alleasl, parlly s imilar 10 il. the mos! rcccnl quolalion (scj-jjnd ler & conrad, 1994) (ll so inc ludes the possibilit y of ass igni ng s. daf­ marica to pratllrfone /!a. our illu s tra ted mate rial (soka c & velic, 1978, pis. 6-9) shows some hilhcr10 insufficient ly e mphasized features which make it poss ible to d ist ingu ish thi s fo rm from p. donifol'ae and to va lidate it taxonom icall y as pratlfr/olle//a dalmatica (sokac & velic) n.comb. as can be seen from table 6, the d iffe rences betwee n p. dol/i lo vae and p. da/matica include the larger height or the rings, large r variat ion range of the did ratio , smaller and more var i­ ab le ramification length, and possib ly smaller number of ramirica tion rows in a ring in p. dal/ilovac. another difference , which has not been adequate ly emphasized to date , a nd cannot be observed from nume rical va lues a lone, concerns the shape of the ramifi cation s: in p. dallilo vae they are c learly fractured at their dista l e nd (radoicic, 1968, pi. i, figs. 2-3; pi. 2, figs. i , 3; pi. 3, figs. 2-4; pi. 4, fig. 4; pi. 5, fig. 4), which is nol vi s­ ible in p. do/matico (sokac & velic, 1978, pi s. 69). the latter has clearly phlo iophorous branches. grad­ ually widening from the base toward their d istal e nd. besides, in p. dollilo\'ae the li ghtly compressed ramifi ­ ca ti ons diverge both upward and downward from the horizonlal plane (rado icic, 1968, pi. i , figs. i -3; pi. 3, fig. 3; pi. 6 , figs. 1,5 and pi. xvi, fi gs. 13-14 in th is pape r) , w hereas in p. do/matico the ram if ications ~ 0 ~ prall/rlol/ella prall/rionella prt/l/lr!oneffa prall/r/olle/ta pra/urlollella pralurlollella k, dal1ifol'ae safemilalla pejol'icae adriarica jordallica neme ;: " (ra do[c[c, [968 ) barattolo, [978 (rado[c [c, [969) (sokac &vellc, 1978) (ku ss & con rad, [991 ) (dragasta n ci ai., [978) ~ il.comb. n.comb. 3 " " 0 < i-ieighl of segments h • 0.95-1.45 • hs 0.5-1.4 • 0,75-0,80 • 0.7-1.2 0.24-0.48 o· • diameter of thallus in the level of segments 0 • 1.10-2.40 • ds 1.3-2.2 • 1.2-3 .04 • 1.60-2.25 • 1.48-2.00 • 0,36 .. ~ • 0.44-0.92 • '" diameter of thallu s between segments d' • 0.40-0.75 '-:> 0.48-0,62 • 0.55-0.84 ~ 3 diameter of central cavi ty d • d; 0.6-1.0 • 0.29-0.72 • 0.52-0.79 • 0.18 :;j' -• o. [9-0.40 0 ~ > relat ion inner/ouler diameter did 0 15-35% "'~ 24-38 % ¢ 22-32 % • 35-40% 32-48% " g' distance between whorls or groups of whorls h • 0.40-0.72 0.29-0.64 q go height of thallus between two segments h ' • 1,451.60 • hi 0.2·1.0 • 0.37,0.43 ~ • 0.079-0.095 > length of ramifications i 0 0.33-0,73 ¢ 0.58-0,68 • 0,69-0 .82 • 0.52-0.62 ;, 0. 14-0.35 ~ diameter of rami fications (distal) p(di"~i) • 0. 16-0 .30 • 0,19-0.32 • 0, 18-0.25 • 0.20-0.59 • 0.031-0.047 1-0.40 0.05-0.13 diameter of ramifications (proximal) p (p. o\ ,) 0 30-35 ji • 35-70}1 • 0.012 0.025·0.07 number of ramifications per segment • 60100 • 50-70('80) • 30-52 r:> 75· 120 • cca.40 eca.50 number of hori zontal row s per segment 0 min. 2 2 3-4 • min. 4 3 -l " cr :.., ('") 0 • "'\ 0 • ~ ~ 0' -. ~ '" v a~:"o:;:;ic\ ; ~ g ng ~9: r ~· ~3 ~ 9. q ;:3 ~3 ~3~§ ~~g~ i';;;;l = ;:!. :;:o"1:l ~.!! ~ :::: :::: 5'~ :::: c: ~ ~ » [ -g. 2i . ~ 3 5' ~ ~ ~. 2 a· ~ 0 co. ~ ~ ~ ~ ~ 2. ~ '" ;7 g 'd ~ -, (5 g' § ~. £, 0'-0 0 "" ~ ~ r~~ : hib o en tr. '0"' ~ xc [ 9· ~ ~ ~. ~ 0: 22 are, in general, obliquely directed upward by varying angles (si milar as in p. salernitalla) and ohen bent like an arch toward the exteri or (sokac & vellc, 1978, pi. 6, figs. 1-2; p i. 7, figs. 1-3), so that sometimes only the dis tal ends of the lowest row of ramifications can be situated below the horizontal plane, i.c. below the level of the lowes t row o f branches (sokac & vellc, 1978, pi. 6, fig. 2 pars; pi. 8, fig. i pars). the d iffer­ ences in the direction of ramification growth result in th e differen t shape of the ca lcareous rings-segments, which is ball -shaped in p. dani/ovae (sec reconstruction in barattolo, 1978, fig. 18), in contrast to p. dal­ mglica where it can be envisioned as being rather bow l­ shaped. all the above rncnlioncd diffe rences seem 10 be sufficientl y clear \0 support the va lidity or p. da/matica. the strat igraph ic pos it ion of thi s species corre ~ spo nds approximate ly to thc barremian s tage, though the small number of find s requires furthe r research. pralurlollella pejovicae (radoicic, 1969) n.comb. pi. xv ii, figs. 814 selected synonvmv: 1969 clypeilla pejovici n.sp. radoic ic, p. 7 1-84, pigs. j ~3 1978 likallella pejovicae (rado ic ic) n.comb. bassoullet et ai., p. 145, pi. 5, fi gs. 1-2 1978 selliporella pejovicae (rado ic ic) n. comb. sokac & vellc, p. 231 , not fi gured 1986 clypeilla pejovicae radoic ic radol c ic:, p. 54, not fig ured 1993 likallella pejovicae (r adoic ic) bueur, p. 103, not figured 1993 falsolikallella pejovicae (radoic ic) dra­ gastan & bueur, p. 17 in the original descript ion of clypeilla pejovicae it was emphasized that thi s species has whorls consisting of two alternating rows of ramificat ions, which grad ual ~ ly and regu larly widen toward their arched distal ends (radoicic, 1969, fi g. la-c, fig. 2g, i, fig. 3a-d). two alterna tive possibil ities have been put forward fo r the ex istence of two rows of branches : firs t, that the fertile ramifications form two consecutive whorls , and second , that we are dealing with olle whorl with numerous ram­ ifications, arranged into two rows, which was cons id­ ered by radoicic (1969) to be a more likely al te rna­ tive. based on the second possibility two rows of branches with in a whorl bassoullet et al. (1978, p. 145) assigned thi s spec ies to likallella as likalle/la pejovicae (radoicic) n.comb. , bas ing their decis ion on what was then generally thought to represent bas ic fea tures of the genus likane/la. radoicic later (rado~ ie le, j 986) maintain s it s assignmcnt to clypeilla and thinks the re are no reasons to transfe r it to likal/e/la, though she docs not give any argument to support her opinion. rare fi nds o f this species, which a re, mo regeo!ogia croatica 49fl over, limited to the dinaric karst region, scem to be the reason for the general neg lect of thi s species and it s exclus ion from com para tive treatmc nts. in the es tab ~ lishment of prafllrlollella, baratto lo ( 1978) ass igned to the new gen us likanella? danilova e radoiclc. but fail s lo mention likanella pejovicae, in spite of the simil a rity between the two spec ies. kuss & conrad ( 199 1) also fai l to mention l. pejovicae in their comparative table that accompanies the description of pra!urlonella jordallica. all this indi ­ cates the fac t tha t p. pejovicae is considered, by the majority of workcrs, as being inadequately known and of unclear systematic pos it ion. the main charac teristics of this species can be sum­ marized as follows: phloiophorolls, c lub-shaped ramifi ­ cations; a rranged into two rows within a whorl (as in p. salemilalla; barattolo, 1978, f ig. 13), or, maybe, two tightl y compressed whorls (as in p. danilovae; bara ttolo, 1978, r ig. 18); the ir arrangement along the tha llus in widely spaced, clearly pronoun ced seg­ ments; s ligh t downward bending of the l ower~row ~ ram­ ifications and s li ght upward inclina tion of the upper­ ro w ramificat ions. if a ll these a re propcrly assessed, thi s spec ies should undoubtcdly be assigned to the genus pratlfr/olle/la. even more surpri si ng, therefore, is its proposal as falsolikallella pejovicae (radoic ic) by dragastan & bueur (1993, p. 17), which was done wi thout any re levant argumentation. thc comparison o f p. pejovicae w ith clypeilla 0110gasli radoicic shows some interesting facts. sadly, in the ori ginal description, c. onogosfi was illustra ted with only two poorly preserved sections (radoic ic, 1986, p. 54-55, pi. 3, figs. 1-2). moreover, if one com­ pares the two descrip tion s radoi c ic (1969) for c. pejovicae and radoi c ic (1986) for c. ollorosli some ident ical features may be noti ced. in both spec ies the branches are rather swollen from the ir vcry base, tubular and slightly widened dis tally, and wit h smooth ~ iy rounded distal ends. in p. pejovicae, the branches a re arranged in (wo rows, whereas c. ollogosfi is sa id to havc individual branches si tuated c ither above or below the whorl leve l as a conseque nce of too littl e space around the comparatively narrow axia l cavi ty to accom­ modate the branches int o one level. the sllille reason­ ing, however, applies to p. pejovicae. in both species, the ramifica tion walls are weakly ca lcificd and, a lso in both spec ies, the branches are more c learly individual ­ ized toward the outer pe riphe ry of the skeleton (com­ pare pi. xvii, figs. 810 in the present paper w it h radoi cic, 1986, pi. 3, fig. i). according to the original descrip tio ns the cl i ffe r ~ cnces in dimensions seem to be somew hat c lea re r, though th is should not be considered a dec isive feature, particularl y because the dimensions fo r c. ollogosfi apparently refer to on ly one speci men (sect ion ). th e purely vi sual impress ion of two rows ramificati ons within a whorl in p. pejovicae and the tendency to atta in s uch an arrangement in c. ollogosf i d oes not seem re li ab le enoug h for the di sti nction o f these two sakai:: taxonomic review of some llarremian and aptian calcareous algae ... species, which raises the question of the validity of c. ollogosti. doubt is further strengthened by the fact that c. ol1ogosti (two specimens?) was derived from the same sample as p. pejovicae, actinoporella podotica (alth), sa/pingopore//a colli (radoicic), s. me/i­ tae radoicic, s. ex gr. gejlevensis, and p. danilovae. the same algal association has been identified in the analyzed sample from the mljet island (m1j -63). beside the illustrated and many other sections of p. pejovicae (pi. xvii, figs. 8-14), sections visually similar to c. onogosti have been observed, which may represent variet ies or atypical sections of p. pejovicae. however, for the time being, it is only necessary to draw attention to the problem of their delimitation or their identity , respectively, despite the inclination towards the latter solution. the definitive answer to this question must await until a more thorough analysis of more numerous and better preserved sections from the typelocality of c. onoros[i is done. based on this study and the ascertained stratigraphic levels, the tota l stratigraphic range o[ p. pejovicae cor­ responds, so far, to the hauterivian and barremian stages. remarks on the species assigned to the genus pratllr/ol1ella: recently granier & berthou (1994) have established the new genus milanovicella, with the most important distinguishing character bcing the two-rowed whorl s of branches arranged at equal distances along the thallus. now, disregarding (for the moment) the genera likal/ella and draconisella, the following questions remain: to which genus pralllr ­ iollclla or milallovicella should the species described above be assigned? the statement of a species having two-rowed or one-rowed whorls of branches seems [or the largest part to be hypothetical, (assu med on the basis of tangential sections, but ones that are too shal ­ low, i.e. do not show the siwation near the main stem) and is therefore a reflection of the author's interpreta­ tion rather than the facts. consider the example of p. iicrae, which will show, r hope , how prob lematic the question is. judging by tangential sections alone (pi. xv, figs. 5,11), p. nerac can be assumed to have two­ fold or three-fold whorls. othcr scctions, however (pi. xv, figs. 15, j8-19), show that at the same level of each of thc transverse section prescnted, two to three rings of pores of branches can be distinguished, cut at different distances from the axial cavi ty. the inner ring with numerous channelets cutting through the cylinder wall (pi. xv, fig. 18) and the inner ring of very tiny pores nearcr to the axial cavity (pi. xv, fig. 19) show that the number of pores is twice, or even more , thc number of large pores that rcpresent the branches of the more distant circle. in contrast to the aforement ioned tangential sections, this suggest one row, or at most two(?) densely packed rows , or branches per whorl. because of all that i.c., the not firmly es tabl ished number of rows o[ branchcs per whorl the ge nus pratifflonella, seems, for the time being, suffi cient to 2] accommodate all related species with similar character­ istics. genus acroporella (praturlon, 1964) praturlon & radoicic, 1974 acroporella rado;cicae (pra turlon, 1964) praturlon & radoicic, 1974 pi. xviii , figs. 1-20 selected synonymy: 1964 acroporella radoicici n.gen. , n.sp. pratur­ lon, p. 177-179, figs. 8-11 1974 acroporella radoicicae praturlon praturlon & radoictc, p. 17-20, fig. la­ b, fig. 2a-d, fig. 3a-d 1984 acroporella radoicicae pra turlon luperto-s innt & masse, p. 339, pi. 33, figs. 1-2 1992 acroporella radoicicae praturlon mancinelli, p. 9-13, pi. 6, figs. l-5 non 1993 acroporella radoicicae praturlon luperto-s inni & masse, p. 300, pi. 4, figs. 11-12 this species was originally dcscribed by pratur­ lon (1964) as a cyl ind rical a lga wit h unsegmented skeleto n, characterized by simple, undivided, acro­ phorous ramifications, situated obliquely, and with an alternating arrangement in consecutive whorls. the ramificat ions are directed upward between of 15-4so from the hori zontal plane. later, pr a turlon & radoiclc (1974) revised the generic diagnosis, adding that long primary ramifications show incipient branching " in clusters of button-like sccondary twigs" at the distal ends. however, compari son between the section illustrated in the origina l description (praturlon, 1964, figs. 8-11) and those illustrated in the revisio n (praturlon & radotctc , 1974, figs. 2-3) shows some additional differences: the cal ­ careous skeleton of the originally depicted specimens shows coarse-grained sparite, which is also the case in sections illustrated by luperto -sinnt & masse (1984, pi. 33, figs. 1-2), mancinelli (1992, pi. 6, figs. 1-5), and in the present paper (pi. xviii, figs. 120), but it is not visible in the sections illustrated by praturlon & radoicic ([974). further, the sec­ tions illustra ted by praturlon & radotcic (1974, figs. 2-3) show an almost ideally rcgular alter­ nating arrangement of branches in consecutive whorl s with constant distance bctween the whorls, whereas this fcature is not so clear by far, nor so constant in the orig­ inally described sections (pra turlon, 1964, figs. 89), or in the sections presented by the above mentioned authors, ancl, particularly, in the sections figured in the present paper (pi. xviii , figs. 1-5,9, 13), which clear­ ly show not only irregularly alternating arrangement of branches (pi. xviii , fig. 2) but also variable distance of whorls. another difference concerns the shape of the 24 tan c1 al.) into the genus pratur{onclla involved the transference of an inadequate holotypc (regardless of the statement in article 7.2 of the icb n that the nomcnclatorial type, i.e. holotypc, is not necessarily the most iypical or representative clement of a taxon) and, consequently and morc important, an inadequate diag­ nosis. however because the above mentioned article legalizes such a transfer and accepts the thus transferred taxon as valid, the necessity of a new diagnosis and a new description in accordance with real characteristics of that fonn appears imminent. diagnosis: small dasyclad al ga with cylindrical cal­ careous enve lope consist ing of ring-shaped segments bearing phloiophorolls ramifications alternating with weakly calcified intervals of the thallus envelope, with­ out ramifications. densely packed ramifications arc tightl y compressed within thin calcareous rings, result­ ing in their inclination into different directions. inner surface of the central cavity is straight to slightly undu­ lated, slightly widcncd in thc central parts of the branches-bearing ca lcareous rings. description: the ncw specics is bascd on the analy­ sis or numerous section s of fragments, among which several include longitudinal or tangential sections cut­ ting more than five branch-bearing rings. the existence of these rings is a consequence of calcium carbonate infillings of space left among the ramifications. the ramifications are arranged along the thallus in succes­ sive inlervals (p i. xv, figs. 2a, 4,14). the calcareous envel ope bet ween the ramifications bcaring rings (segments) are very thin and weakly cal­ cified, so that the skeleton is easily breakable. this is probably the main rcason that the remains of this alga are mostly represented by single rings and only rare ly by skeletal fragments containing 3-4 rin gs . the inner surface is delineated by a st raight to sl ightly undulated wal!. the centra l cavity is s li ght ly enlarged at regular intervals correspond ing to the levels where the ramifi­ cations grow out, forming the calcified rings (segments) (pi. xv, figs. 910). the undivided, clearly phloiophorous ramifications seem 10 be situated in whorls consisting of 2-3 tightly compressed rows of ramifications (pi. xv, figs. 5, 11 , geologia croatica 49/1 16), which occur at regular intervals along the thallus. these feature s, tightly compressed whorls and a com ­ paratively large number of ramifications in a whorl, as well as the widening toward their distal end, give an alternating arrangement of ramifications in consecutive rings and lead to thcir inclination with respect to the horizontal plane. the cx istence of 2-3 densely packed whorls is indicatcd by thc section figured in pi. xv, fig. 16, where a comparatively broad proximal end of the ramifications can be seen, as well as their mutual contact at the base and the well-visible entrance pores, connecting the ramifications with the central cavity, sit­ uated in two closely spaced levels. the same sit uation is suggestcd by the transversc scction figured in pi. xv, fig. 15, which shows a regular circular arrangement of pore of equal-diameter, probably belonging to the same whorl, and , in addition, indicating that the ramifications of one whorl have an approximately equal inclination from the horizontal plane. also the same is suggested by the tangential section (pi. xv, fi g. 11) showing three rows of alternately arranged pores in the middle ring. the smaller diameter of the middle-row pores, compared with that of the lowerand upper-row pores, indicates that the middle-row pores correspond to a sec­ tion of those ramificati ons whi ch are orientcd perpen­ dicularly to the growth direction of thallus. the number of ramifications in a whorl seems to amount to 15-18 and total number of ramif ica tions in a ring (segment) can be estimated to be about 50. similarities and differences: prall/rlol/ella i/erae (dragastan el al.) is ihe smal les t species of ihe genus currently described. it differs from p. dalli/ovae (radotc]c) by the dimensions of all measured cle­ mcnts and, particularly, by the shape of ramifications at their distal e nd, which in p. dani/ovac are more or less dislinctly widened (pi. xvi, figs. 4, 13-14) or even vis­ ibly fractured. further differences includ e s li ght but clearly visible widenings of thc central cavity in p. iicr­ ae at the levels of tightly compressed whorls, which arc not present in p. dani/ovae. with regard to the type­ species, p. sa/erllirana barattolo, p. ilci'({c differs, in addition to being distinctly smaller, a lso by the widenillgs of the central cavity at the leve l of whorls, whereas ill p. salernirana the axial cavity at these levdimensions in mill: total range most frequently maximum observedlcngth (l) outer cli,lineter of branch-bearing segments (d) inner diameter cd) the did relationship distance between two consecutive whorls (11) length of ramifications (1) width or ramirications, distal (p<li,tal) width of ramifications, proximal (ppfoj num ber of ramifications per whorl (w) number of ramifications per ring (segment) 2.4 0.44-0.92 0.19-0.40 32-4f~ % 0.29-0.64 0.1 4-0.34 0.05-0. i 3 0.025-0.07 1518 abollt50 0.5r-0.so 0.20-0.30 34-44 % 0.40-0.60 o. i 8-0.30 0.05-0. 10 0.03-0.04 table 5 dimensions of pmlll/,1m/ella i/c/'{/c (dragastan et al.). sobi::: taxonomic review of sollle barremian and /\pliall calcareous algae ... branches. sections figured by praturlon & radoicic (1974, figs. a-c) show primary branches visibly widening toward the exterior, so that the pore diameter at ihe distal end is twice the diameter at the proxima l end (i.e. , the branches arc club-shaped), which is visible neither in the originally figured sections (praturlon, 1964, figs. 8-9, 11) nor in the present paper (pi. xviii , figs. i, 18-20). both the original and the present material clearly show tubu lar branches that retain ihe same diameter all along thei r length. also, neither of the above mentioned sections, except those illustrated by praturlon & radoicic (1974, figs. 2-3), show secondary ramifications . oblique and tangentia l sections, sllch as those figured in the present paper (pi. xv iii , figs. 2, 4), that pass through !1llmer­ ous whorls and cut the branches at various distance from the axia l cavity (pi. xvin, fig. 4: the pores situat­ ed near the lower tip of the thallus arc being cut at their most distal parts), shou ld in all probability show the "clusters of button-like secondary twigs". therc is not, however, the slightest sign of thcir prcsence. thereforc it follows, that the originally described materia l (as wcll as that figured by luperto-sinni & masse, 1984, mancinelli, 1992, and in the present paper) and thc "revised" material (praturlon & radoicic, 1974) do not belong to the same species. therefore i accept acropore/fa radoicicae as it has been described and illustrated in thc original description (pratur­ lon , 1964). the materials that praturlon & radoic ic (1974) uscclto "revise" ihe genus acrop ­ orella should probably be treated in conncction with thc genus trip{oporclla. a hitherto neglected feature of a . radoicicae, which is clearly visible in numerous sections (about 80) in the available material (which has been collected at several localities in the dinaric karst area), concerns the fis­ sures, or cracks, of the calcareous envelope. the cracks arc bcst visible at the ouler surface, where they are also at their widest , whereas they closc toward the interior (but can, in some cases, reach to ncar the axial cavity). the cracks arc irregular, forming either a mosaicli ke, polygonal meshwork al the surface that encloses all the pores and thereby contributes to sccondary individual­ ization of the ramifications (pi. xviii, fig. 6), or they delimit largcr, irregularly shaped fields on the surface (pl. xvlll , figs. 1,2, 13), or arc scarcely pronounced at all (pl. xvlll, fig. 4). this [eature appears to be pre­ sent also in the tangential part of thc holotype section (praturlon, 1964, fig. 8). it is probably a sec­ ondary characteristic, acquired during diagcnesis, but nevertheless can contribute 10 the very characteristic appearancc of this specics. the stratigraphic range of a. radoieicae can be defined as barremian-aptian, which seems to be well supported at numerous localities in the outer dinarides, as the stratigraphical position of each collected sample is well establ ished. 25 genus clypeina (michelin, 1845) bassoullet et al., 1978 clypeina? solkani conrad & radoicic, 1972 pl. xix, figs. 1-6, 8-10 selected synonymy: 1972 clypeilla? solkani n.sp. conrad & rado­ icic, p. 87 -95, figs. 1-3; pl. i, fig. 4; pl. 2, figs. 1-4 ? 1978 clypeina solkani conrad & radoicic dragastan, p. 109-ll0, 1l3, fig. ih-b 1978 clypeina? solkani conrad & radoicic velic & sokac, p. 317, pi. i, figs. 2-7 1982 clypeilla solkani conrad & radoicic luperto-sinni & masse, p. 864, tabl. 2 1984 clypeina'i solkalli conrad & radoic ic luperto-sinni & masse, p. 339, pl. 33, figs. 3, '14 1986 clypeina? solkalli conrad & radoicic sokac, p. 46-53, pi. 3, figs. 1-5 1987 clypeina? solkani conrad & radoicic radoicic, p. 75, pl. i, figs. i pars, 2-3 1992 clypeina? solkani conrad & rado ic ic mancinelli, p. 9, 13, pl. 2, figs. 1-3; pi. 3, figs. 13-14; pi. 5, fig. 10; pi. 7, figs. 7-9 1993 clypeina'i solkani conrad & radoicic, 1972 bodrogi, conrad & lobitzer, p. 64, pi. i, figs. 3, 6; pl. 2, figs. 3, 6 1994 clypeina? solkani conrad & radoicic bodrogj, bona & lobitzer, p. 233-245, pi. 3, fig. 6; pi. 6, non fig. 3, ?7, pi. 10, figs . 4-7 thi s alga, thoroughly described by its authors (conrad & radoicic, 1972), is characterized by widely spaced whorls of fertile ram ifications, open toward the exterior. each whorl has the shape of a rather thick calcareous disc and bears 8-16 (most fre­ quen tly 10-14) ramifications. ramifications of thc sallle whorl stay in mutual contact for 1/2 to 2/3 or their length. j\ significant remark made by the authors (conrad & radoicic, 1972) refers to the shape of the ramifications, which depends on their number with­ in a whorl. when that number is smaller, the branches are shorter and more strongly widencd toward thc extc­ rior, having a stocky appearance. \vhcn therc arc more branches in a whorl, they are longer and ·more slender, compressed in their proximal half. observations in this study suggest that barremian specimens observed thus far generally have a smaller number (8 -12) of branches per whorl, which rcsults, as mcntioncd abovc, in their stocky, pear-shaped appearance. clypeina? solkani is one of the most common species in the dinaridic karst region of croatia. its presence has bccn cstab lished in western 1st ria , along the coas tal region, and on the islands, at almost every 26 geologia croatica 49/1 dimensions in mm conrad & radoicic 1972 barremian specimens outer diameter (d) inner diameter (d) the did relationship distance between whorls (h) distal diamete r of branches (p dis!) proximal diameter of branches (p prox) number of branches per whorl (w) 0.52 1.20 0.15 0.31 8-16 locality where lower cretaceous deposits are exposed. its s tratigraph ic range can be defined as ranging from the haute rivian to the mid~upper barremian. in hau­ terivian deposits , it is associated with sa/pingoporella anflu/ata, praturlonclla pejovicae, p. dani/avae, humi­ ella leu rae, and numerous unidentified dasyclad remains. among the foraminifera, the majority belong to the long-ranging forms , but campanel/u/a capuel1sis (de castro) is siratigraphically imporlanl. in bar­ rem ian deposits , c.? solkani is accompanied by a rich algal association composed of salpingopore//a mueh/­ bergii, s. me/ifae, s. biokoviellsis, s. dinarica, sa/pin­ gopore//a sp., prafur/olle/la dani/ovae, p. pejovicae, acfinoporel/a podolica, and a c/ypeina sp. in the origi­ nal description of this species, the possibil ity of its apt­ ian age has been assumed. however, this supposit ion has not been proven so far, just as the associa ted fossil assemblage at the type-locality docs not prove this age. there arc some indications that c.? solkani possibly occurs as early as upper valanginian, but so far no uneq uivocally identifiable sect ions have been found. transverse sections which arc often determined as c.? so/kani illay be identical with the scct ions of a so far uniden tified sa/pin[iopore//a. clypeina gigantea n.sp, pi. xvii , figs. 1-7 origin of the name: this species is the biggest spec ies of c/ypeina described so far. type locality: road babino polje sobra, on ihe island of mljct; road cui about 2.15 km before sobra, i.e. iso m before the point marked by coord inates men­ tioned in the description of s. verrucosa (fig. 1). type stratum: well-bedded, light grey, biolurbatcd algal wackes toncs with skletal-moldic cavities of green algae and gas tropods (fig. 2). bioturbalions arc fil led with peloidal grainstone and small benthic foram inifera. depositional envi ronment may be defined as shallow sublidal. holotype: oblique section figured in pi. xvii, fig. 2; thin scction mlj -63/2 1. thin sections made from the topotype material are stored at the institute of geology, zagreb. in total, eight sections of this species were used for the description. 0.48 0.67 0.19 0.28 34 -47 % 0.14 0.25 0.10 0.20 0.02 0.05 8-12 table 7 dimensions of clypeina? solkani conrad & rado­ icic. diagnosis: large c/ypeina with distinctly spaced, saucer-shaped whorls of numerous club-shaped ramifi­ cations and with deeply indented rims. further research may show larger variation ranges, as dimensions refer 10 only 8 specimens (table 8). description: a vcry large clypeina, whose skeleton is preserved as translucent, coarse-grained sparile. cen­ tral cavily appears regularly cylindrical between the whorls and with relatively thick calcareous wall. sec­ tions across that tubular parl of the skeleton suggest the existence of tiny longitudinal tubulcs within the wall. these cannot be connected with the primary ramifica­ tions nor can they be identified with the pores on the corresponding parts of the skeleton in c. jurassica. in transve rse sections cutting the cylindrical skeleton, these tubules appear as tiny, irregular and sometimes indistinci pores (pi. xvii, fig. 3) ihal arc partly visible also in ihe holotype (pi. xvii, fig. 2). the ramifications are phloiophorous and, starling from a comparatively wide pore (pi. xvii, figs. 4, 7), they gradually and regularly broaden toward their distal end (pi. xvii, fi gs. 2-4), sometimes somewhat more abruptly within the first half of their length. each branch has its own calcareous envelope. in their proxi­ mal part , the envelopes, in general but not always, arc in mutual contact. along their distal half, or more, the enve lopes of the neighbouring branches are scparated from each other by narrow and regular, non-calcificd, deep indcnlations (pi. xvii, figs. 3-4). rarely, ihe cal­ cai'cous envelope bends toward the interior at the tip of the branch, which suggests the ir bcing primarily closed. the available sect ions indicate the oblique position of the ramification, directed slightly upward. terminal swelling of ramifications results in their being shifted somewhat below or above the fictitious wavy saucer shaped surface. such ramifications would then appear as more pronou nced ribs on that wavy surface (pi. xvii, fig. 6). similarities and differences: clypeina gigantea n.sp. belongs to the group of large and quite typical species of the genus. with some of its dimens ions (maximum d values), clypeina jurassica may come rather c lose to c. giganfea, but c. jurassica shows a much larger variation range, perpendicular to subper­ pendicular position of branches to the main stem, yel­ lowish calcite in the skeletal structure, thin dark micrisok<ll:: taxonomic review of some barremian and aplian cdcareou$ algae ... tic lin ing around the axial cavi ty, and clearly visible tiny pores w ithin ihe walls of the cylindrical sta lk between the whorls, which is not present in the ne w spec ies. by its outer diameter, c. gigantea falls within the variation range of the poorly known c. hallabaren­ sis y abe & toyama, but c. giganlea has a much narrowe r central cavi ty and larger distal ramifica ti on diameter, is so much more s tron g ly calcified, and the ramifications are c lo ser to a horizontal position. c. gigal/lea is clearly larger than most mesozoic c/ype ina species (c. ealinilia carozzt, c. inopinata favre possibly synonymo us with c. jurassica, see basso­ ullet el a i. , 1978; c. marleli emberger, c. parvli­ la carozzt, c.7 salkani conrad & radoicic, c. zliliielae jaffrezo & fourcade); moreover, il d if­ fers from each of the above mentioned species, taken individual ly, by the degree of calcification, inclination of branches, number of branches in a whorl , shape of the branches, or some other fea ture, which makes it eas­ il y distinguishable. by its much larger size, c. gigantea c learly differs also from the strati graphically c lose c. nigra con rad & peyb ernes (~ aclinoporella nigra (con rad & peybernes ) granier , 1994) as well as from the poorly known, and probably ques­ tionable, c. oilogosli radoicic (see a lso the d isc us­ sion concerning pratur!ollel/a pejovicae), which was derived from the identical barremian algal assoc iation. c. gigal/tea is twice the size of c. neretvae radoictc (accordi ng to the recommendat ion of the icbn, the specific namc should be "i/ere/valla"), which is, more over, morc wcakly calc ificd, particularly the cylindrical parts of the stalk between the whorls, and has more irregularly shaped ramifications which, in contrast to c. gigal/lea, become sli ghtly thinne r toward their dis tal end. c. giganfea is a lso clearly d istingu ishable from c.? o/ra wii radoicic, which has a much broader axial cavi ty, larger number of ramifications in whorl , shorter ramifications, and more closely spaced whorls than c. gigallfea. c. pastriki radoicic is much small er, its branches are shorter than the diameter of the central cavi ty and their number per whorl is about 1/3 of that in c. gigalltea . c. estavezii granier (1986) was inade­ q uale ly descri bed an cl poorly illuslrated (granier, 1986), so that we could only gene rally say that it is di mensions in mm: 27 small e r and with more widely spaced whorls propor­ lionally to its size. c . gigantea also clearly differs from pa laeogene species of clypeina, by its larger si ze, a rather constant did relationship (18-20%), shape and length of ramifications , and somet imes also by the number of ramifications per whorl. stratigraphic position: clypeina giganfea n.sp. has been found in a sample with a rich algal association, composed of numerou s salpillgoporel/a melifae, s. mlfch/bergii, transitional 1"01111s between s. melilae and s. hasi , and less nume rou s s. hispanica, clypeina? solkani, praturlonclla danilovae, p. pejovicae, and numerous unident ified dasyelad fragme nts. among the foramin ifera, there are campane/lu/a capuel/sis (de castro), mayl/cil/a bl/igarica laug cl ai., and ver­ corsella scarsellai (de castro). aboul 20 m above, in the continuou s sequence, s. biokoviensis and s. {trladallasi have been fo und. the wholc microfossi l association, as well as the posi tion of the algal -bearing sample in the cont inuous sequence al the type locality, suggest that the stratigraphic position should be defined as lower barremian. the above mentioned foraminifer­ al species do not contradict that agc, though they arc more common, in th is area, in the upper hauterivian. genus actil/oporella (gumbel in alti-l, 1881) conrad, praturlon & radoicic, 1974 aclilluporella podolica (alti-l, 1878) conrad, praturlon & radoicic, 1974 pi. xx, figs. 1-3 ,5-13 select ed synonymy: 1878 gyraparella podalica n. sp. alfh, pi. 6, figs. j -8, non ri g. 5 1881 aclil/oporelia podotica (alth) n.gen., n.comb. gumbel in alth , p. 322 ( 140) 1974 aelinoporella podotica (alth) emend. con­ rad, praturlon & r adoicic , p. 1-1 5, figs. 1-12 1975 aclinoporelia podotica (alth) drag a s­ tan, p. 66, pi. 33, fi g. 3; pi. 36, fi g. 4; pi. 37, figs. 1,74; pi. 38, fig. 1; pi. 51, 7fig. 2 pars; pl. 52, figs. 2, 4; pi. 71, non fig. 2 ouler diameter of whorls (d) outer diameter of sta lk between whorls (0 ') inner diameter of thallus (d) the did relationsh ip 3. 12 4.35 0.94 1.20 0.54 0.82 8 20 % distance between consecu ti ve whorls (h) length of rmnifications (1) diameter of ramifications at distal end (pd) diamclcr of ramifications allhe base (db) numbe r of ramifications per whorl (w) 0.60 0.72 1.00 1.70 0.28 0.44 0.08 0. 14 25 28 tabte 8 dimensions of clypcilla gigallfea n.sp. 1978 actilloporel/a podolica (alth) dragas­ tan, sucur & demeter, p. 22-23, pl. 4, ?fig. 4; pi. ii, figs. "3, 4 pars. 1978 actilloporel/a podolica (alth) dragas­ tan, p. 11 0-115 , figs. i c-e, pi. 3, fig. i; pi. 5, fig. 3. 1984 actilloporella podolica (altl-i) 1878 emend. conrad et ai. , 1974 luperto-sinni & masse, p. 339, pi. 33, fig. 9. 1986 actilloporella podolica (alth) emend. con­ rad et ai., 1974 gra nier, p. 47-48, pi. 9, rigs. e-h. 1989 actilloporel/a podoliea (alti-i) dragas­ tan, p. 28, pi. 14, ?fig . 4, non fig. 5 1994 aetinopore/la jiodolica (al th) granier, p. 113-117, pi. i. figs. 1,4,8-10; pi. 3, figs. 5-8 1994 actilloporel/a jiodoliea (alth) conrad, praturlon & radotcic schindler & conra d, p. 73-74, pi. 3, figs. 1,3,7-8. aclinoporella podolica (alth) is a well-known species which has been thoroughly rcdcscribcd and illustrated by conrad et al. (1974) . un fortunat ely, the authors chose as neotypc a washed-out spec imen which docs not allow insight into the structure and shape of the ramifications, and whieh are indispensable for the proper generic and species definition. phloio­ phorous branches are arranged into distinctly separated whorls . the essential generic characteristic is the 50called corona, which is the swelling of branches at their base and which is in a . podolica equally well expressed on both the lower and upper sides of a branch. howev­ er, the sections illustrated by schindler & con­ rad (1994, pi. 3, figs. 7-8 ), as well as those in the prescnt paper (pi. xx, figs. 1,5, 10), suggest thc possi­ bility that the corona appears to differ from how it was depicted in the rcconstruction of conrad et al. (1974, fig. 5) taken ovcr also by granier (1994, fig. i), and, instead, seem to give the impression of stunted or incompletely developed second3ly ramifications which also show a phloiophorous shape. this proves the importance of good longitudinal sections for good species determination. isolated rows of mutually con­ nected rings, which may partially correspond to whorls cut through the distal part of the branches, have fre­ quently been ascribed to this species. however, some similarly constructed species (c. g., certain clypeinae) may show almost identical sections (also cutt ing through the outer parts of isolated whorls), which makes the identification of such doubtful sect ions rather risky. this, in turn, has further implications rcgarding the stratigraphic position, geographic di stribution, and ecological requirements of this species. \nh ile single occurrences of a. fjodolica in the dinaridie karst area of croatia, have been recorded in the upper maim, its common occurrence marks the lower cretaeeolls, up to, and including, the aptian. geologia croalica 49/1 genus piriferella n.gen. type of the genus: pin!erella spillosa n.gen., n.sp. origin of the name: the gencrie name derives from lhe typ ically piriferous shape of the ramifications. diagnosis: cylindrical thallus, with thin calcareous envelope, bears apparently densely arranged whorls of large, piriferous, alternately arranged ramifications, each ramification growing out independently and being completely enveloped by its own thin calcareous enve­ lope up to its distant tip. pir~ferella spinosa n.gcn., n.sp. pi. xxi, figs. i-is origin of the name: the name derives from the outer spinose appearance of the thallus, caused by out­ wardly thinn ing ramifications. type locality: road babino polje sabra on the island of mljet; road cut aboot 2 km before sobra ( 17°36'00" e and 42°44'02" n, fig. i). type stratum: well-bedded, lightly coloured, algal-pe lletal wackestones/packstones with fenestral fabric and vadose crystal sill. upper barremian (for details see stratig raphi c position of safpingoporc/la verrucosa and fig. 2). depositional environment: peri­ tidal shallowing upward cycles with black pebble brec­ cia. the algal-bearing samples mostly derive from the firsl, subtidal, member: algal and/or algal-pelletal wackestones, and rarely [rom the second, intertidal, member with fenestral fab ri c: fenestral algal-pelletal wackestones with vadose fabric. holoty!'e: oblique section figured in pi. xxi, fig. 6, thill-section mlj-81/28. paratypes (pi. xxi, fi gs. 1-5, 7-15) derive from the same sample. all material is deposited at the in stit ute of geology, zagreb. the description is based on 20 variously oriented sections from the same sample. diagnosis: alga with a cylindrical thallus, thin cal ­ careous envelope, bearing apparently dcnsely arranged whorls of large, typically piriferous, alternately arranged, obliquely situated, upward directed ramifica­ tions . ramifi cat ions grow out independently, each within its own th in calcareous envelope, and are closed at their distal ends. ramifications of the same whorl or of two consecutive whorls may be separated from each other or they may touch mutually at their maximum swellin gs. secondary calcite deposits in the proximal region (be tween the ramification basses) give an impression of a thicker wall and apparently closer con­ tact between the ramifications. in total, 15 sections have been measured. because of destruction, the outer diameter (d) may be somewhat larger. description: a comparatively sma ll dasyclad alga, having a weakly calc ifi ed thallus that consists or a cylindrical axial cavity with a thin calcareous envelope sob/:: taxonomic review of some barremian and aptian calcareolls algae ... 29 dimensions in mm outer diameter (d) inner diameter (d) the did relationship distance between conseclltive whorls (h) length of ramifications (i) m aximum diameter of ramifications (p max) diameter of the cntrance pore (p pro x) number of ramifications per whorl (w) 0.48 0.s7 0.20 0.34 34 50% 0.10-0.t4 0.22 0.34 0.10 0.19 0.04 0.05 7 8 (pi. xx i, f ig. 2) and bears apparently densely spaced whorls of undivided, typically piriferous ramifications. the inner surface or"the calcareous cylinder is smooth, sharply delimited, and perforated by alternately arranged ramification entrance pores. axial cavity is comparativcly broad. the independently growi ng, typi­ cally pirifcrous, ramifications (i.e. proximally swollen and tapering distally) give a spinose outer appearance 10 thc thallus. undivided, typically piriferous branches, arranged into alternating whorls, grow out independly from each other, each ramification being completely coated by its own th in calcareous cnvelope (pi. xxi, fig. 10). the communication between the axial cavity and the branch is performed through a short pore, sit uated in the mid­ dle of the ramification's base or, sometimes, below it, as the branch 's swelling is more pronounced upward (pi. xxi, fig. i). after the en(ranee pore, each ramifi ­ cation abruptly and regularly swells and then gradually tapers toward its distal end. while the branches of the same whorl, or of two consecutive whorls, are regularly separated from each othcr, they often touch at their thickest part (pi. xxi, fig. 6). narrow spaces between the branches at their base are completely (pi. xxi, fig. 12) or partially (pi. xxi, figs. 9-10) filled by sec­ ondary calcite, wh ich makes the ca lcareous envelope secondarily thicker. the alternating arrangement of branches in the consecutive whorl s (pi. xxi, figs. 7, 12) may not a lways be wholly regu lar, depending on the intensity o/" swelling of the proximal parl or a par­ ticular branch. the branches are directed sli ghtly upwa rds, with their distal ends more strongly bent toward the main stem. though the cysts have not been observed, the strongly swollen branches suggest the cladospore type of reproduction. similarities and differences: piruerella spinosa n.gen. , n.sp. is distinguished by its peculiarly shaped, spinose thallus, wh ich is the consequence of the shape, arrangement, and mode of growth of the branches, and the degree of calcification . at thc gcneric lcvel, pir­ iferella n.gen. clearly differs from clypeina, the latter being characterized by distinctly spaced whorls, with indentcd rims, this being a consequence of branches rnerging together in their prox imal parts and being divided only in thei r exterior (distal) parts. in contrast, pir~ferella n.gen. has more closely spaccd whorls, in table 9 dimensions of pirijerella spinosa n.gen., n.sp. which the branches are allernately arranged (which has not been observed in clypeina) and which may come into mutual contact , both within a whorl and betwecn the consecuti ve whorls. the same features make pir­ (lerella different to actinoporel/a, the latter being addi­ tionall y characterized by the ex istence of "coronas" (i.e. vestibule-like basal widening), after which thc ramifica­ tion shrin ks and then again widens distally (a. podolica). by the arrangement and dens ity of branches, and their independent mode of growth, all of which rcsults in a similar general appearance of the thallus, piriferella n.gen. comes more closely to similiclypeina, which is, however, characterized by actinoporella-type ramifications (i.e., graduall y widening toward exterior) and by vertically flattened coronas. in spite of the simi­ larity regarding the arrangement and density of ramifi­ cations and their thin calcitic envelopes in h%sporel/a (which makes this genus sim ilar to piri!erella), there is a clear difference regarding the shape of the branches: in holosporella, the branches are spherical to hemi­ spherical, in co ntrast to clearly piriferous to phloio­ phorous shape in pirijerel/a. pia (1930) has already emphas ized ihat different gcncra may have the same arrangement of sporangia. this, of course, may result in the very similar or even identical visual appearance of different genera in certain sections. pinjerella spinosa seems to be most similar to clypeina somalica con­ rad et al. (1983), which was subsequently assigncd by bueur (1993) to his new genus similiclypeina. in fact , thc two species are so similar as to belong to the same gen us, which icd to thc proposal of pin/erel/a somatica n. comb. (sec below). thc simi larities bctween the two specics concern the similar dimensions within the same variation ran ge. a morc pronounccd differ­ ence, according to thc original dcscription (conrad et ai., 1983), is visible only in the "h" value , which seems 10 be twicc as large in p. somatica as in p. spin­ osa. as a consequence of this, according to conrad et al. (1983), the consecu tive whorls in p. somalica never touch (though it seems tha t they do, but not as c losely as in p. spinosa). while in p. spinosa the branches grow independently from their base, their envelopes almost always touch at the places of maxi­ mum swell ing. furthemlore, p. somatica is said to have egg-shaped ramifications, as distinct from p. spinosa where the branches are typically piriferous and directcd jo morc steeply upward. though p. somalica still seems to be inadequate ly known, the above mentioned differ­ e nces seem sufficic!1i 10 justify the separat ion of the i wo species. stratigraph ic position: pirijerella spinosa n.gen., n.sp. is assoc iated wit h sa/pillgopore/la ve,.rucosa n.sp. , where the di scussion or its stratigraphi c posi tion is g iven. piriferella solllalica (con rad, p eyi3ernes & masse, (983) n.col11u. pi. xxli , figs. 1 ·20 selected synonymy: 1983 clypeilla soll/alica n.s p . . con rad , pey· bernes & masse, p. 93·95 , pi. 6, fig. 1· 12 1992 clypeil/o? somatica conrad , peybernes & masse · mancinelli , p. 9· 13, pi. 2, figs. 4 ·7, ii 1993 sill/ilic/ypeilla a rr. sall/atica (co nrad , pey· bernes & masse) n. eomb . . bucur , p. 106·107, pi. 3, figs. 7, 9b, 10, 12·25; pi. 4, figs. 4·11. ? 1993 clypeil/a ? somalica (conrad, peybernes & mass e) . luperto·sinni & masse, p. 300, pi. 5, figs. 1· 2 this species was described on comparatively scarce and recrys ta ll ized mate ria l and figured wit h a few coi11plete but damaged sections that do not show all the rel­ evant fea tures. thi s is probably the reason that since [hen the species has seldom been menti oned and even more rarely illus trated. the sectio ns fi gured by con­ rad e[ al. (1983 , pi. 6, figs. 1· 12) seem [ 0 belong [0 he terogeneous ma te r ial , that has been united int o a spec ies. o ne group of re la ted secti ons incl udes the holo[ype and [he para[ypes (co nrad e[ ai. , 1983, pi. 6, figs. 5, 8, 12) and al so some less instructi ve sect ions. another group includes sec tions from prcstat's material (op. ci l, fi gs. 4, 10). heav ily recrys talli zed sec tions, part ly belonging to the type materia l (op. cil , ri gs. 6, 7, 9), seem to include heterogeneous mate ria l, and ihe secgcologiil croalica 49/1 lion figured in fig. ii (op. c it. ) is also probl e matical. 'rhus, sec tions in figs. 6 and 11 hin t at the possibi lity of vcl1 ically ilallcned ramifications. such unclear rc:lati ons prevent thc full ins ight into the actual characteri s ti cs of the s pec ies, which , in turn , makes it s dete rmination exceed ingly difficult (and even proble matic). the lack o f s te rile rami ficat ions (whic h could not be ide ntified , in cont ras t 10 c. j urossica), as well a s ti ghtl y spaced whorls (a \ least in their proximal parts) , led conrad ct al. ( 1983) to cxprcss somc doubts as to the attribution of thi s species to clypeilla. the latter characte ri sti c, the closeness of consecu ti ve whorl s, i.e. ramifications , in the proximal region, w here the space was infill ed by calci te mass, was deemed decisive [or the attribution o f [his species [0 simiticiypeilla (b ucur, 1993). the genus si111iliclypeino was es tab lished wit h s. col/ radi bueur as type spcc ies . it has peculiar, hori­ zontally elo ngated, (i.e., verti cal ly llattcned) swe llings in [he proximal part or [he branches (bucur , 1993, fi g. 3), very s imilar to the coronas in acfin oporello podol ica, the only diffe rence bei ng that in s. conradi these s we ll ings are hori zoll ta ll y e longated , in contrast to a. jjodolica w here they are vertica ll y e longated (conrad e[ ai., 1974, fi g. 5). this feature, [he corona or ves ti bule-like swellings, which seem to actually rep­ resent ineompletcly deve loped secondaries (see pi. xx, rigs. 1, s, 10), and which is thc main diagnos tic feature [or di s tingui shing aclifloporello from clypeina (e.g., acfinoporella mas/ovi pr aturlon is a ss igncd to clypei llo due to the lack oj" coronas), was neglec tcd by b ucu r ( 1993). he based his establi shme nt or a new genus on only one characte ri sti c : the dense , more close­ ly spaccd whorls of ind ividua li zed ramifi cat io ns th at often mutua lly touch, and hence introduced a number of the new combinations: similiclypeino alrmvii (rado­ ic i(:), s. somotico (con rad e [ al. ), s. pi/p"olensis (so kac). the refore, similiclypeillo would include fo rms with d iffere nt c haracte ri s tics: form s w it h hori ­ zontally e longated, coronaor vestibulelike swellings in the proximal part of the ramifications (5. collradi and s.? iusfilliani), form s with 110 sti ch swe l1ings at a ll (s . a/rawli and s. somalica ), and fofms with two types of secondary ram ificat ions, one growing out from the dimensions in mm: clypeil1a soma/jea simi/jclype jllu pirijerella outcr diamcter (d) in ner diameter (d) did relationship distance between consecutive whorl s (h) length of branches (i) diameter of branches (p) number of branches per whorl (w) conrad et ai., 1983 0.47 · o. 80 0.30 · 0.42 36 ·59% 0.23 0. 16 · 0.23 ppm,. 0.04 6 7 aff. somolica solllolica ilucur,1993 thi s pnper 0.33 . 0·54 0.34 · 0.68 0.16 · 0.23 0.1 5 0.38 30 ·46 % 38·55 % 0.07· 0.09 0.10 · 0. 14 0.19 · 0.23 0. 15 · o.is p""o.os·o.11 p.""o.os 0.1 3 5 · 6( 11 ) 6 · 7 table 10 compari son or the dimensions of ciypeil1a soma/icll conrad el ai. , similicfypeina aff. ,mll/aliea bucur and piriferella .tollltllictl. sobi':: taxonomic review of some barremian and aptian calcareous algae ... cylindrical stalk of the thai us , another on the primary branches (5. pupnatensis) . as the basal swelling of the ramifications is generally agreed to be crucial for dis­ tinguishing aclil1opore/la from clypeina, and thus became, by general consensus, a criterion of generic rank, it would be iltogical to e rect a genus that wou ld unite forms with and without such an important feature. alternative ly, if we agreed that a feature serves as a generic trail for di st in guishing clypeina from actino­ porella, the same feature should have the same value in assignin g similar forms to simi/ic/ypeina. this is the main reason for removing s. somalica from the genus 5imiliclypeina and its attribution to the new genus pir­ i/erel/a. in thi s paper, piri/erel/a soll/olieo (conrad et al.) n.comb. is presented with several sections, all of which, except one (pi. xxii, fig. 11), were derived from the same sam pic of barremian limestone from western 1st ria. th is enable get be tter insight into the morpholo­ gy of this form and provided some minor amendments to its description. this is a comparatively small dasy­ clad alga, whose thallus bears densely spaced whorls of ramifications. the shape of the ramifications was described as being egg-shaped. almost completely indi­ vidualized branches are thoroughly coated, each with its own thin calcareous envelope (pi. xxii, figs. 4, 6, 9). more secondary calcite deposits infill spaces only in the most proximal region and thus connect the individ­ ual branches at their very base. in tangentia l sections, the ramifications appear more clearly separated than in p. spinosa, and the pores have a more or less oval to irregu larly elliptical shape (pi. xxi[, figs. 2, 4, 8, 18), indicating that the ramifications are slightly horizontal­ ly flatt ened. thi s is diffcrent in p. spinosa, where, in corresponding sections (deeper tangential sections), pores cut at approximately the same level , appear more or less regularly circular. the arrangement of branches in consec utive whorls is clcarly alte rnating. the branches are perpend icular to subperpendicular to the main stem (pi. xxii , figs. 6, 9). th e compari son of the dim ensions shows general agreement between p. spinosa and p. somalica. in p. soma/ica, the dis tance be tween consecu tive whorl s appears to bc somewhat larger in the original descrip­ tion than in later quotations. the identical p values in p. spinosa and p. somalica may be superficially mislead­ ing: while in p. spinosa the maximum swelling of branches occurs in their proximal part , in p. somalica the same value is attained in the dista l part. this high­ lights the main difference between the two species as being the shape of ramifications and their more pro­ nounced regularity in p. spinosa. in the dinaric karst area, p. somalica has so far been found at two, rather distant, localities : western istria and the west side of the neretva rivcr, upstream from mostar. its stratigraphic posi tion at both localities is barremian; it is associated with sa /pingopore//a mueh/bergii, a sa/pingopore//a sp. , prafur/onella ncrae, cylindroporella ivanovici, and a cylilldroporella sp. 31 acknowledgements t am grateful to my colleagues l. fucek, n. ostric and b. koroltja for thc loan of fo ssil ifer­ ous sample from the islands dugi otok, h var, eres and mali losinj. spec ial thanks go to i. veltc for long­ last ing fiel d collaboration, the determ in ation of foraminifera, and the loan of the cretaceo ll s sam ples from ist ria. thanks go also to j. ttsljar for the sedi­ mentological analyses of the slides and the determina­ tion of th e palaeoen vironm ental sett in gs and t. grgasovic for the help in technical preparation of the manuscrip t. i am especially grateful to i. gusic and to m. conrad for their reviews of the manu ­ script. 3. references alth, a. ( 1878): 0 galicyj skich gatunkach skarn i­ eniajych otwornic rodzaju gyroporella giimbel. ­ rozprawy i sprawozdania z posiedzen wydzialu matematyczno-przyrodniczego, hi akad. umiej w krakowie, v, 7 1-112. alti-i, a. (1881): die versteinerungen des nizniower kalksteines. beitr. pal'iont. oster.-ung. , i , 183332. wi en. barattolo, f. (1978): su di una nuova dasi­ cladacea (alghe verdi) nel paleocene dell' appenni­ no meridionale.boll. soc. natu!". napoli, 87, 1-76. bassoullet, j.p. , bernier.p .. conrad, m.a. , deloffre, r. & jaffrezo , m. (1978 ): les algues dasyciadacees du jurassique e t du cretace.­ geobios, mem. spec. 2, 1-330, villeurbanne. bernier, p. (1984): les formations carbonates du kimmeridgien et du portlandien dans ie jura merid­ ional. straligraphie, micropaleontologie, sedimen­ tologie.doeum. lab. geol. . 92/1, 1-443, lyon. bodrogi, i. . conr ad, m.a. & lobitzer, h. (1993): lower cretaceous dasyclada1es from the villany zone, southwest hungary. biogeographical significance.boll. soc. paleont. ltal. , spec. vol. i, 59-68, mucchi, moelena. bodrogi, i. , bona, j. & lobitzer, h. ( 1994): vergl eschende unters uchung der foraminifcrcn­ und kalkalgen-assoziationen der urgon entwick­ lun g eles schrattenkalks in voralberg (ostcrreich) und der nagyharsany kalkstein formation des vi l­ lany-gebirges (ungar).jubilaums. 20 jahre geol. zusammenarbei t 6sterreich-ungar, 225-283, wien. bucur, i. (1978): microfaciesurile calcarelor albe din partea nordica a masivului piatra craiului. consid­ eratii biostraligrafice, dari de seama al e sedint. lxiv (1976-1977). 4. stratigrafie, 89 105 , bucu­ resti. 12 bucur , i. (1980-198 1): algues calcaires du cretace inr6riclif des monts padurea craiuiui.nymphaca, vtii-ix , 53-68, oradea. bucur, i. (1985): a llew dasycladacean alga in the urgonian limestones from pacturca cra iului (j\pusen i mountains): sa/pingoporella pafrll/iusi il.sp.revue roumaine, geo\. g6oph. g6ogr. , geologic, 29, 8 i -84, bucarcst. bucur, i. ( 1993) : some new or poorly known ea l­ careo ll s algae (dasycladales, gymnocodiaccac) in the lower cretaceous deposits from the res ila­ moldova nona zone (southern carpathi ans, roma­ nia). rev. [span. micropal., 25/1, 93-126. bucur , i. , coc iuba, i & coc iuba, m. ( 1993): microracies and microfossils in the upper jurassic lower cretaceous limestone in the spulhcrn parl or the paclurca crai ului mountains.rom. 1. stratigra­ phy, 75, 33-40, bucurcsti. bystricky, j. (1967) : di e obenriad ischen dasy­ cladazccn clef wcs tkarpatc ll. geo!. sbornik, xv ili /2, 177-364, bratislava. carroz1, a. ( 1953): decouverte du genre salpil/go­ porella dans ie jurass ique superieu r dl! g rand sa leve .arch. sci. genevc, vll , 319-324. conrad, m.a. (1969): pial/ella ~el/ei'el/sis n. sp., une oasycjadacec cladospore des calcaires urgoniens.­ loci. geol. helv., 62/2, 571-582. con rad, m. a. (1970): barremian and lower aptian dasyc ladaccae in the area surrounding ocncva (swi tzerland).geol. romana, ix, 63-100, roma. con rad, m. (1982) : com ments o n korkyrella and other new dasycladaceae.rev. palcobiol. , 1/1 , 1-3. conrad, m.a. & grabner , s. ( 1975): salpil/go­ porella hispallica n.sp. une dasyc.: ladale elu bar­ rcmien des pyrenees espagnolcs.c. r. soc. phys. il isl. nal. geneve. n. s., lx/i -3, 30-39. con rad , m.a. & masse, j.p. (1989): les alg ues ca lcaires des formations carbonatees de i ' ll au leriv­ iell barrem ien pro parte du jura vand ois el nellehfhelois (suisse). mcm. soc.:. nelichal sc.:i. nal., 11 ,277-290. conra d, m.a. & peybernes, b. ( 1976): haute ri ­ vian a lbia n dasycladaceae [rom the urgonian limestones in the french and spanish easlern pyre­ necs.oeol. romana, 15, 175197 , roma. conrad. m.a., peybernes, b. & radoicic, r. (1977): salpil/roporella urladallas; n. sp., une dasy­ clada le du crctace inferieur d 'espagne el de yougoslavie.geolog. mediterrancenne, 4/2, 73-82. con rad , m.a., & peybernes, b. (1978): su r quelques oasycladales de l ' urgo-aptien el u pre balkan bu lgarc.c . r. seances soc. phys. i-fis t. nal. geneve, 12/2-3, 69-83. gcologi<l cro3tica 49/1 conrad, m.a. , peyb ernes, b. & masse, j.p. (1983): clypeil/a somalica n.sp. dasye ladale nou­ ve lle du crelacc infcricur de la plaque africaine (rep. de somat ic, ital ic mcrid ionale).a nn. soc. geolog. du nord, 93-95, lille. con rad, m.a., pr aturlon, a. & radoi cic, r. (1973): reinstatement of ihe genus salpingoporella pia (dasycladaccae) followed by s. sleillhall seri n.sp. c. r. soc. phys. hi sl. nal. genevc, 7/2-3, 103111. conrad, m.a., praturlon, a. & radoicic, r. ( 1974): the genus aclilloporella guembel in al th 1882, dasyc1adajcs, green a lgae, a revision. geo!. roman a, xiii, 1~ 15, roma. conrad, m.a. & radoi cic, r. ( 1972): on mlllli­ aia baconica deecke (characeac) and clypeil/a ? solkolli n.sp. (dasycladaeeae) . a case oj' homeo­ morphism in calcareous green al gae.c. r. soc. phys. hist. nal. geneve, vi/2-3, 87-95. con rad , m.a., radolcic, r. & rioy , y. ( 1976): sa/pillgoporclla hasi n. sp. , une oasyelada le de l 'albian el du c6noman icn elu portuga l ci de ju gos lavi e.c . r. soc. ph ys. hi s\. nat. oencve, n.s., 11/1 -3,99-104. conrad, m.a. & radolcic, r. (1978): salpill go­ porella kafzen· n. sp. une oasycladac6e (a lguc cal ­ caire) nou velle du bcrriasien cl du va langinicn de la region mcdi lerraneene.geo!. vjcsnik, 30/1,6972. conrad, m.a . & v arol, b. (1990): cylil/droporel­ la tal/rica n.sp. urges 10 rev iew di rrcrenl palterns o[ calci fica ti on in the mesozoic dasyclada lcs (green algae).arch. se., 43/1, 193-2 14, geneve. crescent1, u. (1959): sopra una nuova mocroporel­ la (alga calcarea) ncl maim dell' ii alia merid­ ionale.giorn . geol, 27, 195-202, bologna. dragastan , o. ( 1969): alg ues ca lca ires du juras ­ sique sllperieur ci du cretace inferi eur de rollmanie.rev. micropa!. , 12/1,53-62, paris. dragasta n, o . ( 197 1): new a lgae in the jurassic and lower cretaceous in the bicaz va lley (easl carpathians) romania. rev. espan. m ieropal. , 3, 155-192. dragastan, o. (1975): upper ju rass ic and lower c retaceous microfacies [rom the bicaz valley basin (east carpalhians).memoires, instil. ocol. el geophys .. 21, 1-87, buearesl. dragastan, o. (1978): microfacies de la serie cal­ carie cretace infericur ci' aliman (dobrogea de sud) .dari de seam a ale sed inl. , lx iv, 107-136, bllcuresti. dragastan, o. ( 1989): calcareous algae (new and revised). microproblcmalieae and foraminiferida of sokac: taxonomic review of some barremian ,illd aptian calcareolls algae ... jurassic-lower cretaceous deposits from the carpa­ thian area.rev. espan. micropal., 21/1, 5-65. dragastan, 0, bucur, i. & demeter, i. (1978); date noi privind biostratigrafia depozitelor barremian albiene din partea central-estica a zonei resita moldova nona (banat), obtinute prin fora­ jul de referinata de la sopotul non.dari de seama ale sedint., lxiv /5, 17-36, bucuresti. dragastan, o. & bucur, i. (1993): the dasyclad genus radoicicief/a and it s representatives from romania.rcv. cspan. micropal., 25/2, 5-23. elliott, g.f. (1960): fossil calcareous algal noras or the middle east, with a note on a cretaceous problematicum, hellson e//a cylindrica, gen. et sp. nov.quart. j. geol. soc. london, 115/3,217-232. elliorr, g.p. ( 1968): pcrmian to paleocene calcare­ ous algae (dasycladaceae) of the middl e east.­ bull. brit. mus. nat i-list. (geol.), suppl. 4, p. i-ill. farinacci, a. & radoicic, r. (199 1): latc juras­ sic early cretaceous oasyc ladales (green algae) from the western pontides, turkey.geol. romana, 27, 135-165, roma. granier, b. (1986): algues chlorophyceae du juras­ sique terminal et du cretace infe rieur eu alicante.­ mediterranea, ser. geol., 5, 5-96, alicante. granier, b. (1994): the genus aclilloporel/a (gum­ bel in alth, j.881) and its representatives. a review.13eitr. palaont., 19, 113-127, wien. granier, b. & berthou, p.-j. (1994): milallovi­ cella moljlcilialla n.gen. n.sp., une algue oasy­ cladale nouvelle du ponlandien de i' algarve central (portuga l).rev. micropajeont.. 37/2, 113121, paris. granier, b., michaud, p. & fourcade, e. (1986): apinel/a jaffrezoi n.gen. n.sp. algue dasy­ cladacce elu kimmerielgien du chiapas (s ud. est e1u mexique).geobios, 19/6,801-813, lyon. gusic, l. (1966): two new dasyclad species of the subgenu s pial/clio from lower cretaceous of istria. geol. vjesnik, 19, 35-46. johnson, h.j. (1968): lower cretaceous algae from the blake escarpment (atlantic ocean) and from israel. prof. contr. colorado school min. , 5, 71 p., golden. karas, n. & radoicic, r. (1991): salpingoporel/a ph'iniae n.sp. iz barema karbonatllc platforme par­ nasa (kontinentalna grcka).oeo!. an. balk. polll­ os!., 55/1, 163-l73, beograd. koci-iansky -devide, v. & gusic, i. (1971): evolutions-tendenzen der dasycladaceen mit besondcrer bcriicksichtigung neuer funde in jugoslawien.pajaon!. z., 45/1 -2, 82-91. 33 kuss, j. & conrad, m.a. (1991): calcareous algae from cretaceous carbonates of egypt, sinai, and southern jordan.jour. paleon!., 65/5, 869-882. lorenz, m. (1902): geologische studien im gren­ zgebiete zwichen hclvetiseher und ostalpinem facies.bel'. naturf. ges. freiburg br., xii, 34-62. luperto-sinni, e. & masse, j.p. (1982): contrib~ uto della paleoecologia alia paleogeografia della parte meridionale della piattaforma apula nel cre­ taceo inferiorc.geol. roman a, 21, 859-877, roma. luperto-sinni, e. & masse, j.p. (1984): donnees nouvell es sur la micropaleontologic ct la stratigra­ phie de la partie basale du "calcare di bazi" (cre­ tace inferieur) dans la region des murges (italic mcridionale).riv. it. palcont. stra!., 90/3, 331 -374. luperto-sinni, e. & masse, j.p. (1993): the ear­ ly cretaceous dasycladajcs from the apulia region (southern italy): biostratigraphic distribution and paleobiogeographic significance.in: baratto­ lo, f., de castro, p. & parente, m. (eds.): studies on fossil benthic algae. boll. soc. paleon!. ital., spec. vol. j, 295-309, modena. mamet, b. & rudloff, b. (1972): algues car­ bonifcrcs de la partie septentrionale de i ' amerique du nord.rev. micropal. , 15/2,75114, pari s. mancinelli, a. (1992): dislribuzione delle dasi­ c1adali (a lghc verdi) nei sedimenti del crelaceo in fe ri ore in facies di piattafonna carbonatica dell' appennino cenlro-meridionale (lazio e abruz­ zo).studi geol. camerti, 12,7-29. masse, j.p. (1985): pal eobiogeographie des rudistes du domaine peri meditcrranccn a i' aptien inferieur. ­ bull. soc. geol. france, lis, 715-721. masse, j.p. (j 989): relations entre modifications biologiques et phenomenes geologiques sur les plates formes carbonatees du domaine perimediter­ raneen an passage bcdou lien-gargasicn.geobios, mem. spec. 11,279-294, lyon . masse, j.p. (1993): early cretaceous dasycladales biostratigraphy from provence and adjacent regions (south of france, switzerland, spain). a reference for mesogean correlations.in: barattolo, e, de castro, p. & parente, m. (cds.): studies on fossil benthic algac. boll. soc. paleon!. i tal., spec. vol. 1,311-324, modena. mass e, j.p. & luperto-sinni, e. (1989): cylill­ drofjorella iyra'a, nouvelle espece de dasycladale de i' apticn inferieur du domaine pcrimediterraneen nord-occidental.rev. micropal., 32/1, 30-39, paris. misfk, m. (1987): the alga halicoryne c{[}palica n.sp. [rom uppcr triassic of western carpathians. geo­ logica earpathica, 38/3, 285-293, bratislava. okla, m. s. (1995): late cretaceous dasycladales 34 from the aruma formation in central saudi arabia. ­ n. l b. geol. palaonl. mh., 1995, h. 8,475-487. peybernes, b. & con rad, m.a. ( 1979): les algues du cretace infcricur de hongric.bull. cen­ tr. reeh. exp lol".prod. elf aquitai ne, 3/2, 743752,pau. pia , j. (1918): familie: dasycladaeeae (endl. ) cram. em.in: trautll , f. (cd.): das eoz,invorkommen bel radstat im pongau und se ine bez iehun gen zu den gleichailcrigcn ablagerungen bei kirchberg am wechscl lind wimpassing am lci thagebirge.­ dcnkschriftcll der mat hcm. -naturw. klassc, 95, 171278, wien. pia , 1. (1925): einigc nelle oder ungcni.igcnd bekanntc siphoncac vertici llate aus clem mittelcuropi:iischcn malrn.ann. naturhist. museulll wien , 38, 83-88 . pia, l. (1930): upper triassic foss il s from the burmo­ siamese fronti er. a new dasycladacca. holosjjorel­ la siamcflsis nov.gen., nov.sp., with a description of the allied genus acicff/elln pia.india geo!. survey, 63,177-181, calcuta. praturlon, a. ( 1964): calcareous algae [rom jurassi c cretaceous !imestones of centra! apen­ nines (southern lat iulll abruzzi). geo!. roman a, fll, l7 1-202, roma. pri\turlon, a. & radoicic, r. ( 1967): notes on the dasyclad genu s sa/pillgoporel/a pia.geo!. romana, vi, 137144, roma. praturlon, a. & radoicic, r. ( 1974): emenda­ tion of acroporella (dasyc ladaceae).geo!. roma­ na, xlli , 17-20, roma. rado icic, r. ( 1959): salpil/gopo/"e//a dil/a/"ica nov. sp. u donjok redni m sedim entima oinarid a.geo!. glasnik, 3, 33-42, ti tograd. ' radoicic, r. ( 1963): on the new upper jurassic dasyc1adaeea pial/ella gn{(lii nov. gen., nov. spec .­ geol. vcsn ik, sci". a, 20, 189-193, beograd. radoicic, r. (1965): pial/ella tll/"gida n.sp. from the cenoman ian or the outer dinarids.geo!. vjesnik, 18, 195-199. radoicic, r. (1967): salpil/gopo/"ella /iielitae spec. nov. iz donjokrednih scdimcnata spoljasnih dinari ­ da.annal. g601. penins. balkan. , 33, [21-126, beograd. radoicic, r. ( 1968): likal/cl/a , dal/i/ol'ae spec. nov. et que lques autres dasycladacccs cretacees inf6rieurcs des dinarides externes.vesn ik zav. geol. geof. istl"., (a), 26,177193, beograd. radoicic, r. ( 1969): a new lower cretaceous dasy­ cladacea, c/ypeil/a pejovici, and not e on some clypeinae.geol. romana, viii , 7 1-84, roma. radoicic, r. (1975): on likal/e1la i1al1l/lllldai, sp. nov. from the upper cretaceous of the tripoli area geologia croal;c:i 49/1 (lybia) ancl the age of strate containing disso­ cladella all/ill/ara (raineri).annal. goal. penins. ba lkan. , 39, 147152, beograd. rado ic ic, r. (1978): salpil/gopo/"e//a liii/ol'al/ol'ic i n. sp. a new dasyclad from the cenomanian strata of the dinari des and a note on the forami nifer nuii/­ iiililowllilla sp. (arr. reglliaris philippson).­ annal. g601. penins. balkan. , 42, 375-381, beograd. rado ic ic, r. (1979): salpillgoporella ilbaiyd/li, a new senonian oasyc lad and some data abou t sub­ surface biostrat igraphy of the western iraq i deserl. ­ bulleti n aead. serbc sci. art s, classe sc i. mathc­ mat. natul". 68/1 9, 97-105, beograd. radoicic, r. (1986): 0 jednoj novoj klipei ni i nckim drugim dazikladaccama iz jure i krcde crne gore.­ geol. glasnik, 10,53-65, titograd . ri\dolcic, r. (1987): a con tribution to the study of the stratigraphy or hvar (followed by s imultaneous occurrences of the spec ies salpillgoporella me/ilae and s. dil/arica).glas sanu, 5 1, 73-79, beograd. sc hi ndler, u. & conrad, m.a. ( 1994): the lower cretaceous oasyc ladales from the north­ western fri uli platform and their di stributi on in chronostrat igraph ic and cyclostratigraphi c units.­ rev. paleobiol., 13/ i, 59-96. schli\gintweit, f. ( 1990): taxonomic revision or likallella hallllllllda; radoicic 1975, dasy­ cladacea n alga from the upper cretaceous of the northern calcareous alps (gosau formation, coniacian) .rev. pal60biol., 9/2, 257-261 , genevc. s im mons, m.d. , emery, d. & pickard, n.a. i-l. ( 1991 ): hensollella dinarica (radoicic) an orig inal­ ly calci tic early cretaceous dasycladacean alga.­ palaeontology, 34/4, 955-96 1, london. sokac, b. (1986). ciypeilla radici n.sp. (ca lcareous algae; oasyc ladaccae) from th e neocomian of the coastal part of the outer din<.ujcies.geol. vjesnik, 39,43-54. sokac, b. (1992): two new species of calca reous algae (dasycladaceac) from the upper dogger of sout hern dalmatia (croalia).geol. croatica, 45, 15-24. sokac, b. (1993): sa/pillgopore/la robllsta n.sp. (ca l­ ca rco li s algae; dasyc lada lcs) from the uppe r bar­ rem ian lower apt ian of mt. biokovo, croatia.­ geol. croatica, 46/2, 175180. sokac, b. & jelaski\ , v. (199 1): salpillgoporella po/saki n.sp. calcareous algae (dasyc ladaccae) from the cenomanian depos its of the is land of brac. geol. vjesnik, 44, \ -7. sokac, b. & ni kl er, l. (1973): calcareous algae from the lower cretaceous of the envi rons of sokac: taxonomic review of some ilarremian and aptian calcareous a lgae ... niksic, crna gora (montenegro).pal. jugos lav. , 13, 57 p. , zagreb. sokac, b. & velie , i. (1978): redescri ption of the genus sel/ipore/la (cal ca reou s algae; oasy­ cladaeeae) .geol. vjesnik, 30/1 , 225-242. sokac, b. & vellc, r. ( 1979): a new ealcarous alga, sa/pillgoporel/a bikoviellsis n.sp. (oasycladaeeae) from lower aplie n deposit s of mi. biokovo, dal­ matia (south croatia).gcol. vjesnik, 31, 145-150. sotak, j. & misik, m. ( 1993): jurassic and lower cretaceous dasycjacl ajean al gae from the weste rn carpathi ans.in: barattolo, r. , de castro, p. & parente, m. (cds.): studies on fossil benth­ ic algae. boll. soc. paleont. ital. , spec. vol. 1,383404 , modena. tislj ar, j. ( 1986): postanak em ih oblutaka i ulomaka c' black pebbles") u peripli ll1atskim vapnc ilc ima 35 titona zapadne istre i barema otoka mjjela. geo!. vjesnik , 39, 75-94. tisljar , j. & velie, i. ( 1991): carbonate facies and depositional environments of the jurass ic and low­ er cre taceous of the coastal din arides (croati a) .­ geol. vjesnik, 44, 215-234. valet, g. ( 1968): contributi on a i'ctude des dasy­ c1adales. 1. morphogenese.nova hedwigia, xvi, 2 1-82, lohre. velie, i. & sokac, b. ( 1978): biostratigraphi c ana lys is of the jurass ic and lower cre taceolls in the widcr region o r ogulin, centra l croatia.geol. vjcs­ nik, 30/1 , 309-337. yabe, 1-1. & toyama , s. ( 1949) : new dasy­ c1adaecac from the jurassic torin osu lim estone o r the skawabasin sikoku .proe. jap. acad. tokyo, 25/7 , 40-44. manuscript received february 19, 1996. revised manuscript accepted may 27, 1996. i, 4, 6, 101 i 2-3,5 7-9 12-1 3 plate i 1-13 sa/pil/goporel/a mueh/"ergii (lorenz) pia in tra uth tangential oblique sections; figs. 1,4,6, x25; figs. longitudinal oblique sections, x31. oblique sections, x3 1. transvcrse sections, x3 1. 101 i, x3 i. geologia croa!icn 49/1 age and gcncral location: 1,3,9 4 2,5-8,13 10-11 12 lower-middle barrcmi an; field scction 011 thc road cut ncar sobra, mlje t island (pigs . 1-2). lower barrcmian; field scction bravci dolae debelo brdo, mt. dinara. upper barrcmian; velika jezero, mljcl island. upper barremian; mljel island (rig. i). lower barremian; mljcl is land (fig. 1). sokai: plate! 37 38 l,3-4 2 5 6 7 8-9 1012 13 plate jl 1-5 salpillgoporella hm"i conrad, radoictc & rey transverse sections, x57. transverse slightly oblique seclion, x57. rcc ri sta li zcd tangential longitudinal section, x47. 513 salp illgofjorella llielifae radoicic longitudinal tangential section, x23. tangential section, x25. tangent ial oblique sections; fig. 8, x25; fig. 9, x23. oblique scctions, x23. transverse section , xis. age and general local ion: \-5 barremian; eres island. 6, 9, i [-12 lower barremian; field section on the road cut ncar sabra, mljet island (figs. 1-2) . 7-8, 10, 13 upper barremian; veliko jezero, mljet island. geologia croalica 49/1 sob c plate jl 39 40 1 2 3,5,8-9 4 6 7, 10 plate 111 1-2 sa/pil/goporel/a melitae radoictc longitudinal tangential sec tion , x23. a oblique sect ion, b longitud inal section, x l8. 3-10 sa/pil/goporel/a po/ygollalis il .sp., x23 oblique sections; fig. 3 hoiotypc. tangentia l section. longiluciinai oblique sect ion. oblique tangential sect ions. age and gene ral location: 1 upper barremian; velika jezcro, mljcl is land. 2 barremian; gornje igranc, mt. b iokovo. 310 lowe r barremian; field section on the road cut ncarsobra, m ljct island (fig. 1-2), geologia cro;llica 49/1 plate 1ii 41 42 geologia cromica 49/1 plate tv 1-17 salpingoporella polygollalis n.sp., x23 1-5, 7-s b, 1011 ,13 oblique sections. 6 tangential obl ique section. sa-9, 12, 14, j6 t ransverse sections. 15, 17 t ransverse slightl y oblique sections. age ancl general location: 117 lower barremian; field section on the road cut near sobra, mljet island (figs. 1-2). sokac plate iv 43 , '" . • " •• ~ :t <' • \jj j '. fi" 44 1-2 3-4 5-8 9a 10a-lla 9b loblib plate v 1-8, 9a-iia sa/pillgoporel/a hispanico conrad & grabner tangential iongitudjnal sections; fig. 1, x54; fig. 2, xs7. longitudinal sect ions, x57 . oblique sections, xs7. tangential longitudinal section, x36. oblique sections, x57. 9b lib sa/pillgoporella hasi conrad, radoicic & rey longitudinal s lightly oblique section, x36. oblique section s, x57. age and general location: 111 barremian; ercs island. geologia croalica 49/1 sokac plate v 45 46 1,5-8, 10 2,9 3 4 ii 1215 plate vj 115 sa/pillgoporel/a verrucosa n. sp. oblique sections; fig. i, x38; figs. 5, 7-8 , x57; fi g. 6, x38; fig. 10, x47 . longi tudinal sections, x47. tangent ial section, x57. longitudinal slightly oblique section holotypc, x57 . transverse slightly oblique section, x47. transverse sections; figs. 1213, x57; figs. 14-15, x47. age and general location: 115 upper barremian; field section on the road cut near sabra, mljet island (fi gs . 1-2). geologia cro;liica 49/1 sokac plate vi 47 plate vli 1-18 salpillgoporel/a heraldica n.sp. , x31 1-2,4,7,9, 1114 oblique seclions. 3 5-6, sa, 10 15 8b, 1618 tangential oblique section. tangential sections, fig. 5 holotype. transverse slight ly oblique section. tran sverse secti ons. age and genera l location: 118 top barremian or lower aptian; brna village, korcula island (fig. 3). gcologia cro:llic<l 49/1 sokm; plate vii 49 50 i 2 j, 6a 4-5,68,7 8, 10 9 plate viii 110 salpillgoporella llasi conrad, radoicic & rey longitudinal section, x47. tangential longitudinal section, x47. tangential sect ions, x57. oblique sections; figs. 4-5, x47; figs. 6a-7, x57. transvcrse sections, x57. transverse slightly obliquc section , x57. a ge and general location: 110 barremian; cres island. geologia cro;ltica 4\)jl sokac plate viil " geologia cro,uic:1 49/1 plate ix 1-13 salpillgopore/la iirladallasi conrad, peybernes & radoicic 1, 9 longitudinal sections, xs4. 2,4 tnngenliai sections; fig. 2, x44; fig. 4, x60. 3,5-8, ioiia oblique tangenl ial scclions; figs, 3, 7,10, x54; figs, 5-6, x44; figs, 8, iia, x57 . ii b, 12a j3 transverse seclions; figs. lib , 13, x54; fig. 12a, x57 . 12b salpill{;opol'el/a dillgrica radoiciclransverse section, x57 age and general location: 113 top aptian; field section bravci dolac debclo brdo, ml dinanl plate ix 54 gcologi:l cro:llicn 49/1 plate x i a saipillgopore/la iirladaliasi conrad, peybernes & radoicic transverse slig htly o blique section. ib 2,6-7 3 pari. 4 5 8 part. 9 part. salpingoporel/a dinarica radoicic longi tudinal sect ion, b i oblique section, x54. s. iir/adallgsi oblique sections; figs. 2, 7, x54; fig. 6, x45. s. lirladollasi oblique sections, x45. a s. iirladanasi tangential sec tion; i3 s. d;'/cirica tangential section , x45. a s. iirladanasi oblique section; b s. dil1arica tangential section , x57. s. iirladal/asi transverse slight ly oblique sect ion , x54. s. iirladanasi transverse section , x57 . 10-12 saipillgopore/la katzeri conrad & radoic1c, x22.5 10 longitudinal sec tion. i 112 obi ique sections. age and general location: 1-9 top aptian; field section bravei do lae debelo brdo, mt. dinara. 1012 berr iasian; fi eld section south of the peak stratinovac, mt biokovo. sobe plate x 55 56 1-2 3 4 5 6-8, 10 9 plate xi 1-10 sa/pingopore/la dinarien radoicic oblique seclions; ia charophyla; fig. i, x60; fig. 2, x50. longitudinal sections, x60. tangential section, x60. longitudinal tangential section, x60. oblique sections, x60. a tangential section, b oblique section, c transverse section, x28. age and general location: 2, 7 3 4 5-6,8, 10 9 upper valanginian; sosici village, w lslria. aptian; bozavciea bay ncar bozava, dugi otok island. aptian; jesenje hill, se ogulin. aptian; poljana cove, mali losinj island. upper aptian; velo grablje near stari grad, hvar island. middle aptian; field sect ion ncar saranac, mt. biokovo. geologia croatica 4ljfl sokac plate xl 57 58 1,5,9 2,4 3 6 7 8 10 i 1-13 plate xu 1-13 sa/pillgopare/la dillarica rad01c1c oblique sections, x 150. tangential oblique sections; fig. 2, x57; fig. 4, x36. longitudinal sect ion , x36. a oblique section, b transverse section, x44. oblique section, x44. transverse sect ions, x57. transverse slightly oblique section, xlso. oblique sections, x57. age and general location: 2,5,8 -9, 12 aptian; ml velika kapela. 3-4, 6-7, 10-11 , 13 upper aptian; field section on the road cut near sobra, mljet island (fig. 1). geologia croatica 49/1 sokac plate xii 59 i 2,4 3 5 6-8 1-4 5-8 plate xlii ]-8 sa/pillgoporel/a dillarica radoicic tangential oblique sect ion , x42. oblique sections, x42. tangeillial oblique sect ion, x38. longitudinal section, x34. different oblique sections; figs. 6-7, x4; fig. 8, x34. age and general location: aptian; poljana cove, mali losinj island. aptian; bozavcica cove ncar bozava, dugi otok island. gcologb croatica 49/1 lobe plate xlli 6 1 62 i 2 3-9 10-13 plate xiv 1-9 saipijlgoporel/a dijlarica radoicic oblique sect ions, x31. longitudinal tangential section, x31. di fferent oblique sections; fig. 3, x34; fig. 4, x42; fi gs. 5-9, x31. charophytes; fig. 10, x50; fig. 11, x60; fig. 12, x57; fig. 13, x44. age and general location: 1-4,7-9 5-6 1013 aptian; poijana cove, mali losinj island . apt ian; bo7.avcica cove near bozava, dugi alok island. upper valanginian; gustinja cove, se rovinj , lstri a. geologia cro:liica 49/1 sok:lc plate xiv 63 64 plate xv 1-19 pralllriolle/io neroe (dragastan, bucur & demeter) bucur, x32 ib, 2b, 6, 9-10,16 la, 2a, 3-4, 7-8,12-14 5, ii 15, 17, 19 18 longitudinal sections; fig. 2b hololype. oblique sections. tangential sections. transverse sections. transverse s lightly oblique section. age and general location: 1-19 top barremian or lower aptian; brna village, korcula island (fig. 3). gl:ojogia croatica 49/l plate xv 65 66 2 3 4-6,8,1215 7,9-11 plat e xv i i-is prallfr/onella d{/ili/ovae (radoicic) barattolo a pm/lff{ollella danilovae oblique sec tions, x16. b sa/pillgopore//a me/if({e tangenti al sec tion, x 16. c pralur/ollclla pejovicae obl ique section, x16. d sa/pingoporella sp., x 16. p. doni/ol'oe differe nt sec tions, x 16. longi tudina l and transverse sections, x22. different oblique sections, x22. transverse s li ghtl y oblique sections, x22. age and general location: lls lower barremian; field section on the road cli t ncar sabra, mljcl is land (figs. 1-2). geologia croalica 49fl platexyi 67 68 i 2 3a 5-6 7 8 910, 13 12 ii 14 plate xvii 1-7 clypeina giganlea il. sp. , x 18 transve rse sect ion. oblique section , i-1olotype. tral1svcrs~ slightly oblique sections. tangential sections. transverse section. 814 pratllriollella {jejovicae (radoicic) n.comb. , x22 tangential longitudinal section. oblique sections. tangential ancltransversc oblique sections. tangentia l section. transverse slightly oblique section. age and genera l location: 114 lower barremian; ri eld section on the road cut near sabra, mljet island (rigs. 1-2) geologia croatic<l 49/1 sobi:: plate xvii 69 7() 1, 4-6, 9-10 2 3,7 -8, 11-14,1617 is 18-20 plate xviji 1-20 acroporella radoicicae (praturlon) praturlon & radolcic obl ique tangential sections, x23 . tangential section, x 18. oblique section s; fig. 3, x 18; figs. 7-8, 11 14, 16-17, x23. transverse oblique section, x23. transverse sect ions, x23. geologia cro:uica 49/1 age and generallocatioll: 1-7, 9, 12-20 8,1oll lower aptian; nw from the bridge on the mreznica river, between primislje and ju zbasici. upper aptian; fi eld section dravci do b e dcbelo brcio, mt. dinara. sokac plate xviii 71 72 1-2, 4 ,6 3,5 8 9a, 1o 7 9b plate xix 1-6, 8-10 clype!lia? solkall! conrad & radoicic tangential longitudinal sections; fig. 1, xi8; figs. 2, 4, 6, x23. longitudinal sections, x29. oblique sections, x23. transverse sections, x23. ,s'a/pill[:oporclla mclitae longitudinal section, x23. sa/pil/goporel/a biokol'iclisis oblique section, x23. age ancl gcncrallocalion: 1-5,7-10 6 barremian; gornjc 19rane, mt. biokovo. upper barremian; velika jezero, mljc\ island. geologia croalic;1 49/1 plate xix " ( ( ",-__ 10 73 74 gcologin cro~tici149/1 plate xx 1~13 act;lioporella podolica (alth) conrad, praturlon & radolctc, x23 i, 2a, sa long itudinal sections. 3a, 6, 8\ 0, 13 diferclll oblique sections . 4a,7, 11 tangential sections. 4c c/ypeina? solkani longitudinal slightly oblique section. 12 28,38 413,513 transverse section. sa/pingoporc//a !/ielirae oblique sections. sa/pillgopore//a muehlbergii oblique sections. age and general location: 1 ~ 13 upper barremian; velika jczcro, mljet island. sobc plate xx 75 76 geologia cro<l!lca 49/1 plate xx i 1-15 pirijerella spil10sa n.gen., n.sp.; fig. i, x38; figs. 215, xso 1, 4-8,11 , 13-14 oblique scct ions; fig. 6 holotype. 2 longitudinal section. 3,9, 12 tangential sections. 10,15 transverse slightly oblique sections. age and general location: 115 upper barremian; rield section on the road cut ncar sobra, mljcl island (figs. 1-2). platexxt 77 78 plate xxii 1-20 pirilerella somalica (conrad, peybernes & masse) il.comb., x46 1-2,5 , 11 , 14-15, 19 oblique sectiolls. 3-4, [8 tangential sections. 6, 9-10,13 7-8,1 2, 17 16, 20 longitudinal sections. tangential oblique sections. transverse sections. age and general location: 110,12-20 ii upper barrem ian; sea-side 3 km n [rom porec. barremian; raska gora, w side of neretva river, ne mostar. geologia cmalica 49/1 sokat plate xxii 79 so geologia croatic:l 49/1  environmental changes in the lower mirna river valley (istria, croatia) during the middle and late holocene  igor felja1, alessandro fontana2, stefano furlani3, zlatan bajraktarević1, anja paradžik1, ena topalović1, sandro rossato2, vlasta ćosović1 & mladen juračić1 1 university of zagreb, faculty of science, department of geology, horvatovac 102a, 10000 zagreb, croatia (igorfelja@geol.pmf.hr, mjuracic@geol.pmf.hr) 2 university of padova, department of geosciences, via g. gradenigo 6, 35131 padova, italy (alessandro.fontana@unipd.it) 3 university of trieste, department of mathematics and geosciences, via weiss 2, 34127 trieste, italy (sfurlani@units.it) doi: 10.4154/gc.2015.16 abstract sedimentological, macroand micropaleontological analyses on 3 cores down to 13 m depth were carried out in the lower section of the mirna river valley, in order to study the depositional facies and the environmental evolution. the holocene marine transgression reached upstream for 7 km from the present-day coast, while in the last 7 ka it was followed by progradation of the mirna river estuarine delta. the protected coast offered by the lower valley and the strong input of fresh water led to the presence of a brackish microfauna in front of the river mouth. the oldest sediments in the cores were characterized by the dominance of ammonia beccarii and significant proportions of elphidium spp. and miliolids suggesting a marine/estuarine origin. the foraminiferal assemblage in the overlying sediments became less diverse, as the relative abundance of elphidium spp. and miliolids dropped, implying a shift to a transitional environment (inner estuarine/lagoon facies, bb). sediments originating in hyposaline marshes (facies ba) had the lowest foraminiferal species diversity index (a. beccarii predominated over trochammina inflata and haynesina sp.). since late-antiquity a significant input of alluvial matter led to the deposition of several metres of silty clay sediments which reach >9m thick in the m3 core. the sediment supply has been partly increased by deforestation carried out in the mirna catchment area. this was particularly extensive from the 15th–19th centuries and fed the fluvial system with large amounts of material, causing the increase of sediment input and rapid progradation of the estuarine (bay-head) delta. this study also highlights the potential role of hand augering in sampling and describing the subsoil for reconstruction of the geomorphological evolution of the area and supporting the study of past relative sea levels, climate changes, and anthropogenic activities that occurred during the holocene. keywords: sedimentary facies, karstic estuary, lagoon, bay head delta, foraminifers, radiocarbon age, adriatic sea where steep coasts are common and the coastline is often strongly indented (furlani et al., 2014). holocene sediments are extensive along the italian side, reaching up to 40 m in thickness, and the study of the lagoon and shallow-marine facies allowed detailed description of the marine transgression (e.g. brambati et al., 2003; amorosi et al., 1. introduction the northern adriatic coast is characterized by the dramatic morphological contrast between the low-lying landscape of the northwest coast, with sand ridges and lagoons (castiglioni, 1997) and the rocky coast of the eastern side, geologia croatica 68/3 209-224 9 figs. 4 tabs. zagreb 2015 geologia croaticageologia croatica geologia croatica 68/3geologia croatica 210 2008). in contrast, along the northeast coast between monfalcone (italy) and bar (montenegro), the quaternary deposits are rare, often very thin, and generally limited to several places often in protected bays (pikelj & juračić, 2013; ogrinc et al., 2007; pavelić et al., 2014). such a patchy distribution is related to the lithology and geological structure of the coast implying limited sedimentary supply from the karstic rivers. generally, along the eastern adriatic coast, the surface hydrographical network is poor and the alluvial inputs reaching the sea are generally scarce. there are a few exceptions for example the neretva or raša river systems, having high terrigenous load from allogenic sources in the hinterland. a few studies, derived from scattered drill cores, document the significant thickness of the holocene coastal sequence in some of these terminal valleys, as in the neretva river (vranješ et al., 2007), rječina river (benac & arbanas, 1990) and raša river (sondi et al., 1995). in the dragonja river, near sečovlje, the base of paralic deposits was discovered 26 m below the surface and was dated to about 10,000 years bp (ogorelec, 1981). in the eastern part of the northern adriatic region, in istria, one of the largest deltaic plains is the lower valley of the mirna river, with particular environmental characteristics that have attracted historians, archaeologists and geographers since the end of the 19th century (see carre, 2007; d’incà, 2007 and references therein), but little attention has been paid to the geomorphological and geological aspects. the aim of this research is to describe the holocene succession of depositional facies recorded in the terminal sector of the mirna river valley through sedimentological, macro and micropaleontological analyses of sediment cores. moreover, this study highlights the potential role of such investigations in reconstructing the geomorphological evolution of the area and supporting the study of past relative sea levels, climate changes and anthropogenic activities that occurred during the holocene. in this work we tested the use of hand augering in sampling and describing the subsoil for the first 5–15 m, suggesting that, due to its cost-effectiveness, it is potentially useful in sampling other low-lying areas along the eastern adriatic coast that are sometimes remote and not easily accessed with the standard mechanical boring equipment. 2. regional setting 2.1. geological setting the mirna river is located in the north-western part of the istrian peninsula, western croatia. it is the longest river in istria (53 km), with a hydrographic catchment of approximately 400 km2. karst processes strongly affected the carbonate formations of istria and led to the development of complex and well-developed underground water circulation, thus, beside the surficial basin, the mirna river has a hydrogeological catchment estimated to about 580 km2 (boži čević, 2005). the source of the mirna river is near the town of buzet and it discharges into the adriatic sea near the town of novigrad (cittanova) (fig. 1). the drainage basin of the mirna river is composed of carbonates, mostly cretaceous and eocene limestone, and clastic eocene deposits (flysch, figure 1: location of the study area. the digital elevation model (dem) obtained from nasa-srtm data. the boundary of the hydrogeological catchment is assumed (according to santin, 2013). felja et al.: environmental changes in the lower mirna river valley (istria, croatia) during the middle and late holocene geologia croatica 211 polšak & šikić, d., 1963; pleničar et al., 1965) (fig. 2). these marl and sandstone sediments in alternation (flysch) in the catchment area are morphologically related to a badland landscape (gulam et al., 2014). from the beginning of the 20th century, a number of karstic springs were documented on topographic maps of the lower tract of the valley, but they partly disappeared after land reclamation. the gradole spring is the largest one (fig. 3), with an estimated minimal discharge of 500–600 ls–1 (magdalenić et al., 1995). from a structural point of view, the area is part of the external dinarides that are dominated by limestone deposited on the adriatic carbonate platform from the lower juras sic to the eocene (velić et al., 2002) (fig. 2). the dinarides are characterized by compressional tectonics, with maximum stress aligned ne-sw and thrust and reverse faults that strike nw-se (castellarin et al., 1992; vlahović et al, 2005). seismotectonic activity is not significant in the study area, but there are historical records of a number of very strong earthquakes in the vicinity, such as in the gulf of rijeka (faivre & fouache, 2003). some authors, such as be nac et al. (2004; 2008), antonioli et al. (2007), faivre et al. (2011) and furlani et al. (2011) suggested that a sudden holocene sea-level rise (approximately 0.5–1 m) in the area of the north-eastern adriatic could be triggered by an earthquake that submerged the archaeological remains and geomorphological forms (such as marine notches). several geomorphological, biological and archaeological markers have been used as a source of information from which the relative movements between land and sea have been evaluated. holocene submersion was largely completed about 7 ka bp and subsequently the sea level rose slowly to the current elevation (antonioli et al., 2007, 2009). sea-level markers indicate a vertical tectonic signal at a rate of about –0.75 mm/yr occurring during the last two millennia that produced a significant relative downdrop of the coastline of about 1.5–1.8 m (antonioli et al., 2009, faivre et al., 2011). the sea level change occurring in the istrian coast since about 5 ka bp, has been estimated as a relative rise of about 4 m (faivre et al., 2011). figure 2. a geological map of istria (modified after the geological map of croatia, croatian geological survey, 2009); 1. fault, 1a. thrust, 2. quaternary deposits (mainly holocene), 3. terra rossa deposits (holocene). 4. flysch deposits (eocene), 5. liburnia deposits, foraminiferal limestone and transitional deposits (paleocene?, eocene), 6. rudist limestone (cretaceous), 7. dolomite and breccia (cretaceous), 8 limestone and dolomite (cretaceous), 9. limestone and dolomite (jurassic). figure 3: map of the lower valley of the mirna river. the hillshaded dem was obtained by digitalization of the isolines represented in the topographic map at scale 1:25,000. geologia croatica 68/3geologia croatica 212 2.2. archaeological setting istria was reached by neolithic people between 5800–5600 bc, when the first farmers settled in the area, especially along the coast (forenbaher et al., 2013). a major phase of occupation occurred in the ancient and late bronze age, characterized by the so-called castellieri cultural group. this is related to the construction of fortified villages on hills (i.e. the castellieri), defended by sub-rounded drywalls (sakara sučević, 2004). the late bronze age population mainly concentrated in a few large centres that probably later became the major roman cities. romans occupied istria between the 2nd and 1st century bc and they built a complex network of roads and widespread systems of fields (i.e. centuriatio). at that time, the mirna river was probably called the ningus and some historical sources describe the existence of an important protected harbour, most likely near the present area of ponte porton (parentin, 1974; carre et al., 2007; d’incà, 2007) (fig. 3). historical chronicles and maps depict the strong progradation experienced by the river mouth during and after the medieval age, up to the present that transformed most of the lower valley into a swampy environment (d’incà, 2007). novigrad (cittanova) became the major city of the area from the byzantine period and during the venetian domination the river assumed the name of quieto, describing its calm flow. a major phase of land degradation occurred between the 12th and 19th centuries, when the istrian woods supplied the shipyards in venice (parentin, 1974; d’incà, 2007). historical documents testify to the existence of a harbour near the chapel of s. maria of the bastia in 1582 ad and the archaeological evidence documents that at the site of the chapel the valley floor rose about 4.6 m between 1582 and 1857 (milotić & prodan, 2014). since the second half of the 19th century, during the austrian domination, there have been interventions to regulate the river e.g., some artificial cutting of meanders, but a huge reclamation plan was undertaken during the 1920s–1930s (parentin, 1974; san tin, 2013). the lower valley of the mirna was transformed into the present farmland through the construction of artificial levees and a dense network of ditches connected to pumping stations. after the 1964 flooding, the reclamation works were completed (santin, 2013). 3. material and methods 3.1. sampling and core description the corings were done with an ejikelkamp hand auger (fig 4a) using an edelman head for sediment above the groundwater table and 1 m long gauge below the groundwater table. samples collected through the edelman head have a vertical length of 10 cm and a diameter of 7 cm and each sample could be mixed during coring operation. in contrast, gouge samples are generally almost undisturbed and, especially in silty and clayey deposits, internal depositional features like millimetric laminations could be preserved. the use of the gouge allowed the recovery of samples with a vertical length of 0.5 or 1.0 m and a diameter of 3 cm (fig. 4b). the depth reached in the cores was constrained by the limits of the equipment and, in particular, by the stiffness and friction opposed by the sediment or by the collapse of the hole. the depth of the samples was checked in the field and the uncertainty was ±0.05 m. cores m1 and m3 were drilled in january, while core m2 was collected in may 2013. the coordinates of the sampling sites and their elevation were measured in the wgs84 system using a leica differential gps with a vertical precision of ±0.02 m. the elevation measures were corrected to the local geoid considering as a reference datum the top of the present salt marshes existing in mirna bay (fig. 3), which is considered to be 0.20 m above mean sea level. the cores were described in the field, but soon after they were protected with aluminium foil and sealed in plastic bags to preserve their characteristics for further lab analyses. the sediments were described following the method explained in fao-isric (2006): sediment colour and texture, primary sedimentary structures, and the type and concentration of accessory materials (e.g., roots, plant debris, organic matter, shell macrofossils and soil characteristics) were the main features reported. the colour of the layers was determined by comparing the moist sediment with the munsell soil colour charts, while the content of calcium carbonate was estimated observing the reaction with hydrochloric acid (10% of concentration) on a scale from 0 to 4 (fao-isric, 2006). the shells and their fragments were determined in the field and some have since been checked in the lab with a stereomicroscope. 3.2. foraminiferal analyses the micropalaeontological analyses were carried out on selected sub-samples. due to the limited width of the cores (3 figure 4: a) coring operations in the salt swamp at the mouth of the mirna river; in the distance the highway viaduct over the mirna river valley is visible. b) a sample of laminated sediments collected through the gauge head from core m2 between 8.04–8.15 m. felja et al.: environmental changes in the lower mirna river valley (istria, croatia) during the middle and late holocene geologia croatica 213 ta bl e 1: d is tr ib ut io n of fo ra m in ife rs in th e co re s m 1, m 2 an d m 3. depth of the sample (meters) number of the sample ammonia sp. ammonia beccarii trochammina inflata haynesina sp. porosononion sp. elphidium sp. elphidium crispum elphidium aculeatum elphidium macellum triloculina sp. triloculina marioni quinqueloculina seminula pyrgo sp. adelosina mediterranesis sigmoilinita costata bulimina sp. brizalina sp. lagena sp. indeterminable total co re m 1 0. 10 – 0 .1 5 1 23 12 0 81 58 3                           6 29 1 1. 75 – 1 .8 0 2 12 13 1 97 74 9                           3 32 6 1. 95 – 2 .0 0 3 19 17 0 28 54 25 1                         7 30 4 2. 15 – 2 .2 0 4 30 13 8 47 78 18                           3 31 4 3. 15 – 3 .2 0 5 40 16 8 22 44 7                           10 29 1 3. 45 – 3 .5 0 6 38 19 5 23 21 11                           11 29 9 3. 95 – 4 .0 0 7 20 17 8 28 44 11                           17 29 8 5. 00 – 5 .0 5 8 35 17 0 20 35 19         3   4             12 29 8 5. 75 – 5 .8 0 9 25 17 5 18 42 17 2 5     2 2 3               29 1 6. 30 – 6 .3 5 10 22 16 5 44 27 18 2 1       5 6 2       4   8 30 4 7. 40 – 7 .4 5 11 11 98 9 23 27 12 27 23 11 2 14 18 5 2 1 1 3     28 7 7. 95 – 8 .0 0 12 15 76 7 14 15 20 54 8 17 8 25 34 5             29 8 co re m 2 4. 50 – 4 .5 5 1                                       0 5. 00 – 5 .0 5 2                                       0 5. 20 – 5 .2 5 3 37 20 5 35                               34 31 1 5. 60 – 5 .6 5 4 30 20 8 23 32                             13 30 6 6. 80 – 6 .8 5 5 29 22 0 27 25                             10 31 1 7. 80 – 7 .8 5 6 32 22 9 31 21                             9 32 2 8. 20 – 8 .2 5 7 30 21 8 7 23 7             2             15 30 2 8. 50 – 8 .5 5 8 14 21 2 14 39 12 4 3 3     1 1             5 30 8 9. 70 – 9 .7 5 9 26 23 4   7 13 3 2 3                     7 29 5 10 .5 0 – 10 .5 5 10 20 18 6 2 23 17 6 11 6     4 5   2     4   16 30 2 11 .1 0 – 11 .1 5 11 17 15 7 2 27 10 16 4 7   1   45         1 1 7 29 5 12 .2 0 – 12 .2 5 12 21 21 4 2 15 4 12   3   2 6 25 2           4 31 0 12 .6 5 – 12 .7 0 13 30 17 3 3 23 5 14 4 3   2 5 31 2           7 30 2 12 .9 5 – 13 .0 0 14 37 19 7 2 41 2 5       1 4 7             4 30 0 co re m 3 1. 75 1 .8 0 1                                       0 1. 85 – 1 .9 0 2                                       0 3. 55 – 3 .6 0 3                                       0 4. 00 – 4 .0 5 4     2                                 2 6. 95 – 7 .0 0 5 3 6 1 3                             4 17 7. 30 – 7 .3 5 6   2                                 1 3 8. 00 – 8 .0 5 7 1                                   1 2 8. 95 – 9 .0 0 8 2 6 4 3                             1 16 geologia croatica 68/3geologia croatica 214 cm), every sub-sample was 5 cm thick. twelve samples were taken from core m1, 14 from core m2, and 8 samples from core m3. sediment was treated with diluted hydrogen peroxide for one day to remove organic matter, washed on the 63-µm sieve and left to dry. samples which contained foraminiferal tests were split by a reich-microsplitter into aliquots with approximately 300 specimens. species and genera were identified via stereomicroscope following the ge ne ric classification of loeblich & tappan (1988) and cimerman & langer (1991). besides the species and generic identification, biodiversity indices were also calculated. statistical analyses were done using the past software (hammer et al., 2001). in each sample the number of species and individuals was counted. species diversity was estimated based on the following indices: species richness (s), dominance (d), fisher α index, shannon-wiener index (h) (murray, 1991). in table 1, the total number of counted specimens is presented, but the percentage was not expressed in order to avoid misleading data about m3, where the total number of foraminifers was less than 20, and statistically insignificant. 3.3. radiocarbon dating during field description of the cores, the layers containing suitable material for radiocarbon dating (e.g., organic-rich sediments, peaty horizons, wood fragments, and selected shells) were sampled immediately, sealed in plastic bags and afterwards dried. among these samples, particular attention was devoted to the layers representative of activation or deactivation phases of sedimentation (e.g. top of organic horizons of soil or salt marsh). three samples were selected and radiocarbon dated with the ams method. in order to avoid calibration problems related to reservoir effect on carbonate material (i.e. shells), only plant or wood fragments were dated. the analyses were carried out by the ion beam laboratory of eth in zurich, and the ages were corrected with the oxcal software version 4.2.3 (bronk ramsey, 2009), using intcal13 atmospheric calibration curves (reimer et al., 2013). in the text, dates are presented with a precision of 2σ. 4. results 4.1. core m1 the core was drilled near the viaduct overpassing the mirna river valley (fig. 3) and reached 8 m in depth (fig. 5). the site [45°19’56.6’’n – 13°37’30.1’’e] is located about 2200 m east of the artificial levee providing a coastal barrier to the sea and is 0.6 m below present mean sea level (msl). remains of cerastoderma sp. and, secondarily, other lagoon shells (e.g. nassarius sp.) were locally scattered at the surface. the core stratigraphy is characterized by the following layers: 0–1.85 m: silty clay and clay with light olive brown colour (2.5y 5/4) with a high carbonate content. the present plough layer ends at 0.40 m and, below it, mottling features with a yellowish brown colour (10yr 5/6). iron stains of 2–4 mm diameter are abundant until 1.10 m and common to figure 5: stratigraphic log of core m1 with diagrams of some selected foraminiferal species. legend is presented in fig.6; asl – above mean sea level. felja et al.: environmental changes in the lower mirna river valley (istria, croatia) during the middle and late holocene geologia croatica 215 scattered in the lower part. an isolated valve of scrobicularia plana was present at 1.5 m, but shell fragments were generally absent or very rare and of millimetre dimension. between 0.40–0.80 m rare carbonate concretions (up to 5 mm of diameter) were present along with manganese nodules (1 mm diameter). the lower boundary was sharp and eroded part of the lower layer. dominant foraminiferal species were ammonia beccarii, trochammina inflata and haynesina sp. (tab. 1). 1.85–2.60 m: down to 2.25 m this layer was formed by greenish grey (g1 5/10y) silty clay with lenses of dark-greyish brown clay (2.5y 4/2-1). the sediment was characterized by very poor or no reaction with hcl and dispersed organic matter in the matrix. lagoon shells, fragmented and complete, were quite abundant (cerastoderma sp., cyclopes sp., gibbula sp., bittium sp. and loripes sp.), along with millimetre plant debris. similar features and shells were present down to 2.60 m, but around 2.20–2.30 m there was a gradual transition to clayey silt with a lighter greenish grey colour (g1 4/10y). ammonia beccarii and trochammina inflata were dominant foraminiferal species. compared to previous interval specimens of a. beccarii became more abundant, while those of t. inflata decreased in number (tab. 1). 2.60–3.0 m: silty clay and clayey silt, grey in colour (2.5y 6–5/1), and with medium-strong reaction with hcl (3). shell fragments were very rare. the layer was partly reworked during coring operations due to the occurrence of the groundwater table. 3.0–4.9 m: alternations of clay and silty clay sediment with a general grey colour (g1 5/10 y) and a medium reaction to hcl (2). this layer was characterized by the common presence of lagoon shells, both fragmented and well-preserved (bitium sp., cerastoderma sp., rissoa sp., gibbula sp., loripes sp.); some of the fossils showed weathering features including traces of partial dissolution. millimetre sized plant debris was common and abundant in some decimetre intervals, where the matrix colour was dark-grey brownish (2.5y 4/2). some seeds were also present. figure 6: stratigraphic log of core m2 with diagrams of some selected foraminiferal species; asl – above mean sea level. geologia croatica 68/3geologia croatica 216 the proportion of a.beccarii in the foraminiferal assemblage continued to increase, while the proportion of t. inflata and haynesina sp. decreased (tab. 1). 4.90–8.0 m: soft sediment consisting of grey clay and silty clay (g1 5/10 y) showing a strong reaction with hcl (3–4) that suggests a higher proportion of carbonate compared to the layers above. shell remains were rare or absent, with a specimen of abra sp. and rissoa labiosa at 5.55 and 5.75 m respectively. plant remains were common in some laminated decimetre intervals of the core. from 5.00–5.05 m rare specimens of miliolids occurred (triloculina sp., quinqueloculina seminula). at 5.75 m a few tests of elphidium sp. were observed. although ammonia sp. dominated in the assemblage from 7.40 7.95 m, the trend of decreasing abundance was obvious. at the same time, a greater number of unidentified miliolids and elphidium sp. was recorded (tab. 1). in the 12 samples analyzed in this core a total number of 17 benthic foraminiferal species were recognized (tab. 1). foraminiferal tests were present in all samples, but more species were present below 5.00 m. a. beccarii dominated in all the studied assemblages, while t. inflata and haynesina sp. were present in greater amounts in the shallower and were less common in the deeper horizons. representatives of the genus elphidium and miliolids were more abundant below 7.40 m. at depths of 6.30 m and 7.40 m a few specimens of brizalina sp. and bulimina sp. were identified. 4.2. core m2 the core site was about 500 m north of the bridge crossing the mulski creek and 100 m north of the mirna river [45°20’53.91”n–13°40’13.87”e] (fig. 3). ground elevation is +2.4 m msl and the area was a swampy environment until the beginning of the 20th century, when it was reclaim ed. the core stratigraphy is characterized by the following layers (fig. 6): 0.0–2.60 m: clayey silt of a light brown and yellowish colour (2.5y 5/4) and high to medium reaction with hcl (3–4). the plough layer was stiff and stopped at 0.40 m depth where the lower boundary was sharp and erosive. mottling features 2 mm wide, yellowish brown in colour (10yr 5/6) were common from 0.40 m and abundant between 1.40–2.60 m. fragments of roots were sometimes present throughout the layer and common at its base, where a gradual transition marked the limit with the lower layer. at 2.5 m the teeth of a small carnivorous mammal were observed. 2.60–3.90 m: greenish-grey (6/5 gy) clayey silt passing to silty clay and clay below 3.2 m. sediment strongly reacted with hcl (4) and soft carbonate concretions (<3 mm diameter) and also hard concretions (2–3 mm) from 3.0 m to the base was common. root fragments were common throughout the layer and also some millimetre fragments of freshwater molluscs were observed. 3.90–5.45 m: clay and silty clay with slightly dark greenish grey colour (5/5 gy) with intercalations of organic-rich intervals at 3.90–3.95, 4.20–4.25 and 4.75–4.90 m, where the colour is dark greyish brown (10yr 3/2) and hcl reaction is poor (1). some isolated carbonate concretions were discovered, up to 2 mm in diameter. plant macroremains were common through the whole layer, but especially between 4.95 and 5.30 m, where roots and other parts had centimetre dimensions and the sediment was lighter in colour (6/10y). the lower boundary was sharp. a plant fragment at 5.27 m depth was radiocarbon dated to 1782±25 years uncal bp (138–332 ad, 2σ calibration) (tab. 2). no foraminifers were observed above 5.20 m depth. 5.45–5.80 m: greyish brown clay (2.5y 5/2) with organic matter dispersed in the matrix up to 5.65 m; millimetre and, secondarily, centimetre sized plant remains were common and their distribution highlights a laminated pattern in the sediment; it gradually passes to the lower layer where lagoon shells were present. a. beccarii dominated the foraminiferal assemblages, while ammonia sp., t. inflata, haynesina sp., and porosononion sp. were subordinate (tab. 1). 5.80–10.25 m: grey and greenish grey clay and clayey silt (5/n–6/10y) characterized by a soft consistency and with intercalations of laminated intervals of decimetre thickness. laminae were of millimetre thickness and were evidenced by the alternation of dark grey (5n, 2.5y 4/1) and light greenish grey (7/n–10y) layers. scattered isolated shells of lagoon molluscs and fragments were present (cerastoderma sp., loripes sp., gibbula sp., abra sp., rissoa sp., nassarius sp.), but some concentrations occurred at 8.34–8.40, 8.51–8.57, 8.71–8.75, 9.10–9.17; 9.30–9.37; 9.45–9.53 m. millimetre plant remains were dispersed and sometimes common, highlighting the lamination, which was particularly evident between 7.90 and 8.20 m. in some intervals, e.g. between 8.75–9.75 m shells were partly dissolved. in all samples in these intervals a. beccarii was the most abundant foraminifer. at 8.20 m representatives of miliolids and elphidium sp. were observed, but only by several specimens. 10.25–13.0 m: grey clay and clayey silt (6/n–10y) characterized by their soft consistency. this layer was similar to the one above it, but was characterized by the scarce or rare presence of shells; one cerithium sp., at 10.40 m and another at 12.20, one juvenile valve of gastrana fragilis at 11.40 m and an adult at 12.20 m, limnea sp., rissoa sp., nuculana sp. and loripes sp. at 12.25 and one centimetre sized fragment of mytilus sp. at 12.72 m. millimetre sized plant remains were dispersed in some intervals, with leaf fragments being represented. this plant debris highlighted the horizontal layering but their occurrence was not so frequent as to indicate a laminated pattern. centimetre sized wood fragments have been documented at 10.55, 11.40 and 12.20 and 12.25 m. at 11.40 m a 3mm sized, rounded fragment of charcoal was found. a fragment of twig found at 12.25 m of depth was radiocarbon dated to 5774±28 years uncal bp (4702–4547 bc, 2σ calibration) (tab. 2). felja et al.: environmental changes in the lower mirna river valley (istria, croatia) during the middle and late holocene geologia croatica 217 ta bl e 2: r ad io ca rb on d at in g. sa m pl e co re la b. c od e m et ho d d at ed m at er ia l co nv en tio na l 14 c a ge er ro r ca lib ra te d ag e 2σ 9 5. 2% p ro b. (y r c al . b c/ a d ) δ1 3c ‰ pd b lo ng itu di ne w g s8 4 la tit ud e w g s8 4 su rf ac e el ev at io n (m m sl ) d ep th fr om su rf ac e (m ) co rr ec te d el ev at io n (m m sl ) m ir 269 0 m 3 et h -5 71 32 am s pl an t m ac ro fo ss il 85 4 24 11 54 -1 25 4 a d -2 5. 6 45 °2 1’ 8. 68 ’’ 13 °4 2’ 41 .3 8’ ’ 4. 40 6. 9 -2 .5 m ir 552 7 m 2 et h -5 71 33 am s pl an t m ac ro fo ss il 17 82 25 13 833 2 a d -2 7. 2 45 °2 0’ 53 .9 1” 13 °4 0’ 13 .8 7” 2. 00 5. 27 -3 .2 7 m ir 512 25 m 2 et h -5 71 34 am s w oo d tw ig 57 74 28 47 02 -4 54 7 bc -2 7. 4 45 °2 0’ 53 .9 1” 13 °4 0’ 13 .8 7” 2. 00 12 .2 5 -1 0. 25 ta bl e 3: b io di ve rs ity fo ra m in ife ra l i nd ic es o f t he se le ct ed in te rv al s o f t he c or e m 1. d ep th o f s am pl e (m ) 0. 10 –0 .1 5 1. 75 –1 .8 0 1. 95 –2 .0 0 2. 15 –2 .2 0 3. 15 –3 .2 0 3. 45 –3 .5 0 3. 95 –4 .0 0 5. 00 –5 .0 5 5. 75 –5 .8 0 6. 30 –6 .3 5 7. 40 –7 .4 5 7. 95 –8 .0 0 n um be r o f s pe ci es (s ) 6 6 7 6 6 6 6 8 10 12 17 13 n um be r o f s pe ci m en s ( n ) 29 1 32 6 30 4 31 4 29 1 29 9 29 8 29 8 29 1 30 4 28 7 29 8 d om in an ce (d ) 0. 29 4 0. 30 4 0. 36 4 0. 29 0. 38 3 0. 45 5 0. 39 7 0. 36 4 0. 39 8 0. 33 4 0. 16 0. 13 5 sh an no nw ie ne r i nd ex (h ) 1. 37 1 1. 32 7 1. 33 6 1. 42 4 1. 27 6 1. 16 8 1. 27 9 1. 41 4 1. 35 4 1. 56 7 2. 25 5 2. 25 4 fi sh er α in de x 1. 07 1. 04 4 1. 27 8 1. 05 2 1. 07 1. 06 3 1. 06 4 1. 51 3 2. 00 6 2. 49 4 3. 95 5 2. 77 4 ta bl e 4: b io di ve rs ity fo ra m in ife ra l i nd ic es o f t he se le ct ed in te rv al s o f t he c or e m 2. d ep th o f s am pl e (m ) 5. 20 –5 .2 5 5. 60 –5 .6 5 6. 80 –6 .8 5 7. 80 –7 .8 5 8. 20 –8 .2 5 8. 50 –8 .5 5 9. 70 –9 .7 5 10 .5 0– 10 .5 5 11 .1 0– 11 .1 5 12 .2 0– 12 .2 5 12 .6 5– 12 .7 0 12 .9 5– 13 .0 0 n um be r o f s pe ci es (s ) 5 6 6 6 7 12 8 13 14 12 13 10 n um be r o f s pe ci m en s ( n ) 31 1 30 6 31 1 32 2 30 2 31 8 29 5 30 2 29 5 31 0 30 2 30 0 d om in an ce (d ) 0. 41 4 0. 46 0. 46 9 0. 48 0. 54 0. 46 0. 64 0. 39 8 0. 31 3 0. 49 2 0. 35 8 0. 46 6 sh an no nw ie ne r i nd ex (h ) 1. 18 8 1. 15 5 1. 15 1. 12 1 1. 01 8 1. 27 0. 84 1. 51 7 1. 65 6 1. 24 5 1. 55 9 1. 16 3 fi sh er α in de x 0. 84 6 1. 05 8 1. 05 4 1. 04 7 1. 28 2. 46 5 1. 51 6 2. 76 4 3. 05 7 2. 48 2 2. 76 4 1. 99 1 geologia croatica 68/3geologia croatica 218 elphidium spp. increased in number at 10.50 m and miliolids (quinqueloculina seminula) at 11.10 m. a. beccarii was still dominant in the deeper horizons (tab. 1). altogether, in 14 samples from this core, a total number of 16 benthic foraminiferal species were recognized while the two shallowest samples were barren (tab. 1). with the appearance of elphidium sp. and miliolids at horizons deeper than 8.20 m, the species richness increased significantly. a. beccarii made up more than 50% and in some samples more than 75% of the total assemblage and was the dominant species. the proportion of trochammina inflata in the assemblages decreased with depth. in contrast, elphidium sp. and miliolids appeared at 8.20 m below the surface and became more numerous with depth, reaching a maximum proportion at 10.50 m. 4.3. core m3 the core [45°21’8.68’’n – 13°42’41.38’’e] reached 9 m in depth and was collected in the floodplain at an elevation of +4.5 m msl, 700 m downstream of the chapel of s. maria of the bastia (fig. 3). the core stratigraphy is characterized by the following layers (fig. 7): 0.0–2.50 m: yellowish brown clayey silt and silty clay (2.5y 5/4), with strong reaction with hcl (4–3) and with the presence of some centimetre sized plant remains, probably corresponding to roots. 2.50–5.10 m: yellowish brown silty clay and clay (2.5y 5/4) with dispersed yellowish brown mottling (10yr 5/8) and carbonate concretions (3–8 mm); reaction with hcl was strong (4). presence of millimetre to centimetre sized plant remains was common and most of them probably correspond to roots. millimetre fragments of shells of fresh-water gastropods were present below 4.0 m. 5.10–7.0 m: greenish-grey clay (6/n–10y) with common presence of centimetre sized roots and the occurrence of millimetre fragments of fresh-water gastropods. hcl reaction was high (4–3) and the layer was slightly mottled with yellowish features (10yr 5/4) in the upper part, down to 5.50 m. 7.0–7.4 m: slightly dark grey silty clay (2.5y 5/1) with medium-low reaction with hcl (2) and a common presence of millimetre fragments of fresh-water gastropods, especially at 7.3–7.4 m. 7.4–8.0 m: greenish-grey (6/n) silty clay, clay and silt. 8.0–8.20 m: slightly dark grey silty clay (2.5y 5/1) with organic matter present in the matrix and with a medium – low reaction with hcl (2). the presence of bioturbation related to detritivore fauna and some millimetre fragments of fresh-water gastropods was observed. 8.20–9.0 m: grey clay (6/n–10y) with some plant remains and the presence of millimetre fragments of freshwater gastropods. a millimetre sized fragment of wood from 8.30 m was dated and gave the radiocarbon age of 854±24 years bp (1154–1254 cal ad) (tab. 2). among the analyzed samples, 3 were completely barren and in the other 5 only very few foraminifera were observed (a maximum of 17 specimens at a depth of 5.50 m). a. beccarii, t. inflata and haynesina sp. were recognized (tab. 1) and, due to their low abundance, no biodiversity indices were calculated for this core. 5. discussion the occurrence of fine grained sediments throughout the sedimentary columns generally facilitated hand augering to the significant depth of up to 13 m. this confirmed the possibility of investigating a significant volume of deposits and studying the evolution of the area since 6500 years bp (fig. 6). despite small grain-size differences through the cores, the combined use of sedimentological, macroand micropalaeontological characteristics allowed the recognition of different depositional environments and the reconstruction of their longitudinal and vertical distribution (fig. 8). 5.1. depositional environments 5.1.1. continental environments (a) in the lower sector of the mirna valley continental deposits crop out extensively and generally form the present surface and the topmost subsoil. they consist of homogeneous silty and clayey sediments, without visible lamination or other depositional structures, except for planar bedding. roots were rather common and their diameter ranged from 1 to 10 mm, whereas the macropalaeontological content consisted only of fragments of fresh-water snails, which are generally figure 7: stratigraphic log of core m3. legend is presented in fig.6; asl – above mean sea level. felja et al.: environmental changes in the lower mirna river valley (istria, croatia) during the middle and late holocene geologia croatica 219 not abundant. these deposits were oxidized and partly affected by pedogenesis for several metres, from the ground surface down to the top of the water table. this interpretation is supported in this interval by the occurrence of mottling features with a yellowish and reddish colour (10yr 6/8) and, between 2 and 3.5 m, by the presence of calcium carbonate concretions, both soft and hard. concretions are related to the leaching of carbonate from upper horizons and re-deposition in the lower ones; their width was <10 mm and this small dimension was likely to be related to the short time (i.e. few centuries) that has elapsed since the deposition of the alluvial parent material or before their burial by younger sediments (retallack, 1990). also the shallow depth at which the groundwater table is generally present in the area contrasted with the development of the pedogenic processes (cf. mcrae, 1988). thus, the pedological profiles of present and buried soils are weak and they could be classified as entisols and rarely as inceptisols according to the usda pedological descriptive code (soil survey staff, 2003). in the investigated area, the deposits interpreted as continental facies are normally barren for foraminifers, but in the basal portion of core m3, a very small number of specimens of ammonia beccarii, trochammina inflata and haynesina sp. were discovered. their occurrence could be related to some transport processes from nearby lagoonal environments or from the reworking of slightly older lagoon sediments. considering the location of core m3 which, according to historical sources, in the last millennium was very close to the mirna channel, there could be another explanation that due to the low-lying setting of the lower valley and the slightly pensile position of the mirna channel, it is possible that floods boosted by extremely high tides (the so-called acqua alta) periodically transported brackish or marine microfauna landwards away from the river mouth. before the dyke construction of the 20th century, similar episodes were likely to occur along the last few kilometres of the valley (santin, 2013). the distinction of different alluvial facies is normally strongly connected to grain-size diversity, in particular to the figure 8: stratigraphic logs of the studied cores with presumed depositional facies. on the top of the figure the schematic topographic profile of the lower valley is presented. asl – above mean sea level. geologia croatica 68/3geologia croatica 220 occurrence of coarser sediments in the fluvial channel or in its proximity (e.g. miall, 1996). however in the lower valley of the mirna river the late-holocene deposits consist only of mixtures of clays and silts, while sands are almost completely lacking, even at a few metres distance from the active channel. this particular characteristic is a limit to the possible differentiation of alluvial facies and is mainly related to the strong presence of flysch formation in the catchment that consequently fed the fluvial system almost exclusively with finegrained particles. no evidence of channels or natural levee deposits was found in the cores. it is likely that in the investigated area, even the channel facies were composed of silts and clayey silts while, possibly, some slightly coarser elements (i.e. sand) were present, but only as the basal lag, due to the fact that fine-grained marls dominate exposed flysch sequences in the mirna river catchment. thus the late-holocene stratigraphy was characterized by facies of the floodplain (aa) and alluvial swamp (ab). the latter was marked by the occurrence of organic-rich and peaty layers where plant macroremains could be common or abundant. seeds and fragments of leaves could be present. the ab facies was clearly recorded in core m2 between 3.95–5.20 m (fig. 8), while it was not documented in m1 and m3. in the core m3, the slightly elevated organic layers observed at 7.0–7.4 and 8.0–8.2 m were interpreted as the a horizons of soils with a very weak degree of development (i.e. entisol), with a profile consisting only of horizons a and c. this suggests that they developed during a limited period without sedimentation in the area of core m3, and probably in a poorly-drained environment that hampered pedogenic evolution. 5.1.2. brackish/transitional environments (b) the depositional environments related to brackish waters were generally marked in the core by the presence of shells. in particular the occurrence of cerastoderma glaucum and eventually the association with loripes and bittium generally characterizes the hyposaline marshes (ba) and the inner estuarine/lagoon facies (bb). sediments deposited in these facies were not distinguishable from each other at the macroscopic scale and the lithology in both cases comprised grey and greenish muds, with a soft consistency, with a variable degree of bioturbation and the presence of millimetre sized plant debris. the recognition of facies ba was based on benthic foraminiferal assemblages. the hyposaline marshes and marginal environments were strongly dominated by a. beccarii and, secondarily, by t. inflata and haynesina species (murray, 1991, 2006; albani et al., 2007; amorosi et al., 2004, 2005). in core m1, such an assemblage was present almost from the surface down to 4.0 m and in m2 between 5.20–7.85 m. these intervals were characterized by low values of the fisher-α index (1.04–1.28 in m1 and 0.85–1.05 in m2; tabs. 3, 4) all these data, together with a shell–type ratio triangular diagram (modified after murray, 1974; fig. 9) suggest that sedimentation took place in brackish swamps or ponds on tidal flats with the occasional influx of freshwater from the mirna floods (fig. 8). the inner estuary/lagoon setting (bb) coincided with the presence of elphidium spp. and miliolids (like quinqueloculina seminula) in the cores (intervals 5.0–6.35 m in m1 and 8.20–9.75 m in m2; tab. 1). these foraminiferal groups are considered as pioneers (vaniček et al., 2000; debenay et al., 2001) and their presence suggested changes in environment towards more stable, marine conditions (murray, 2006). somewhat higher values of fisher-α indices (1.51–2.49 in m1 and 1.28–2.47 in m2) and a greater number of species (up to 7–12 species) are in accordance with such a hypothesis (tabs. 3 and 4). there are some differences in the composition of foraminiferal assemblages observed in this study and from the northern adriatic lagoons (venice, marano and the grado lagoons, albani et al., 2007; melis & covelli, 2013). in areas where salinity fluctuates, opportunistic and pioneer species prevail, but the absence of some species (i.e. a. tepida in this study) could be related to the laboratory method used (a few studied samples, from a 13m long core, and 14 sub-samples were analyzed), the diameter of the drill (which gave a limited amount of sediment sample), poor preservation of foraminiferal shells that only allowed identification to generic level. however, foraminiferal studies of sediments from the northern adriatic, confirm that representatives of a. beccarii dominate in very-shallow water marginal environments, where nutrient inputs periodically led to oxygen deficiency (donnici et al., 2002). trochammina inflata and a. beccarii outnumber other foraminiferal species in marsh assemblages (scott & medioli, 1978; amorosi et al., 2004; albani et al., 2007). considering that most of the investigated sediments were related to brackish waters, analysis of ostracod and diatom assemblages would probably help in discriminating the brackish environments, where this kind of ecological indicator could highlight subtle variations in the degree of salinity and water circulation. 5.1.3. estuarine/outer lagoon environment (e) the deep parts of the cores m1 and m2 were characterized by the presence of grey and greenish grey muds with soft to normal consistency and the widespread presence of laminated intervals. the laminae are millimetres thick and could be slightly organic, sometimes evidenced by the concentration of plant and wood debris. shells were not abundant, even rare in some portions and these characteristics contributed to differentiating this facies from ba and bb. moreover, in e the species cerithium sp., nuculana sp. and mytilus sp. have been observed, indicating a relatively higher salinity. the foraminiferal assemblage was related to estuarine/ outer lagoon conditions where the marine influence is stronger (fig. 8; fig. 9). while the proportion of t. inflata and haynesina sp. specimens decreased, miliolids, (q. seminula in particular) and elphidium spp. increased. this was evident in intervals 7.40–8.00 m in core m1 and 10.5–13.00 m in core m2 (tab. 1). values of the fisher-α index in these intervals ranged between 2.77–3.96 in m1 and 1.99–3.06 in m2. assemblages were characterized by greater species richness, greater values of the shannon-wiener index (tabs. 3 and 4) and greater abundance of miliolids and rotaliids. the felja et al.: environmental changes in the lower mirna river valley (istria, croatia) during the middle and late holocene geologia croatica 221 presence of infaunal species, including brizalina sp., despite their low number, indicated that in the near bottom environment normal marine conditions prevailed. all this information suggested a stratified estuary/outer lagoon environment in the geomorphological setting of the valley with protection offered by mirna bay from sea-storms and waves. we interpreted this facies as outer lagoon /estuarine conditions, in a subtidal environment influenced by freshwater inputs related to mirna river activity. the lamination was probably induced by the fluvial floods, which transported sedimentary pulses rich in vegetation and wood remains to the river mouth. a particular and local condition is represented by the additional influx of fresh water along the final tract of the mirna river by important karstic springs, such as the gradole spring (fig. 3). due to the large hydrogeological catchment feeding the gradole spring (113 km2) it is characterized by a fairly uniform discharge (the ratio of minimum and maximum discharge is 1:20) not really affected by short meteoric-climatic periods (magdalenić et al., 1995). in the protected environment of mirna bay, the fluvial and karstic freshwater probably induced the occurrence of a highly stratified/estuarine environment even in the area in front of the mouth of the mirna where, in a different geomorphological setting with an open coast, a marine fauna would be generally present. moreover, as discussed for the continental facies, and for the macrofossil associations of the brackish and marine environments, the lack of sand and coarser sediments could partly limit in the mirna valley the application of the mollusc associations as they have been generally defined in the mediterranean (e.g. peres & picard, 1964). 5.2. evolution of the mirna valley from m3 to m1 there is an elevation difference of approximately 5 m, but the gradient is ~ 1.0‰ between m3 and m2 and it falls to almost 0 between m2 and m1 (fig. 8). the occurrence of areas below the present sea level, downstream of the highway viaduct (fig. 3), is a consequence of the reclamation works carried out in the area in the 19th and 20th centuries. part of this topography below msl is related to the original morphology of the swampy and lagoon environment, but it is also partly the result of induced subsidence, prompted by water expulsion, soil ripening and degradation of organic matter since reclamation, as documented in other similar areas (e.g. tosi et al., 2000). this topographic setting is consistent with the results evidencing that alluvial aggradation in m3 has been significantly higher, with at least 8 m of fluvial deposits. considering the stratigraphy, it is likely that lagoon or transitional deposits could be present even in the m3 site, but at deeper horizons (fig. 7). considering only the direct information documented in m2, it is evident that marine and transitional environments were present in the early holocene over 7 km further inland than at present. thus, the studied cores testify that the estuarine (bay-head) delta progradation occurred approximately in the last 7000 years, with the seaward migration of continental facies. considering the geomorphological setting of the valley, prodelta and marine facies related to the early holocene stages of the transgression should be present in deeper layers not reached by the cores. this hypothesis is supported by the geometry of the lower valley, where the boundary between the quaternary units and the bedrock is more than 100 m below the present surface (up to 160 m, igh, 1994), allowing the accommodation space necessary for recording early-holocene and even previous deposits. comparing the studied area with the adriatic basin and the post-lgm sea-level curves, measured or modelled reconstructions for istria and the surrounding areas (correggiari et al., 1996; lambeck et al., 2004; antonioli et al., 2007; 2009; amorosi et al., 2008), the expected age of the basal holocene paralic facies should be around 10–9 ka bp, when the sea level in the adriatic was approximately 30 m below the present msl. the stratigraphic setting documented in the mirna river valley should be comparable with the situation found in the terminal tract of the other istrian rivers, as in the bays of sečovlje, koper and raša. at the moment, only a few cores are available in those areas and they do not allow detailed description of the late-holocene depositional units. holocene coastal evolution is well documented along the western coast of the northern adriatic, where deltaic progradation started from about 7500 years ago (e.g. amorosi et al., 2008 and references therein), but the low-lying landscape is different from istria. despite the diverse dimensions and geographical setting, a rather good analogue for the lower valley of the mirna river can be represented by the tagus river valley, near lisbon (vis & kasse, 2008; vis et al., 2009). in particular, the brackish-water marshes and tidal flats described in the subsoil of the tagus mouth present many similarities figure 9: shell–type ratio triangular diagram (modified after murray, 1974). (ba) hyposaline marshes; (bb) inner lagoon (hyposaline lagoon); (e). estuary/outer lagoon. geologia croatica 68/3geologia croatica 222 with facies ba and bb documented in this study. a particular characteristic of the mirna valley is the lack of coarse deposits in the middle and late holocene and, thus, even the foreshore and shore-face facies (bay head delta and prodelta) consist of fine grained material (i.e. clays and silts). this singularity partly hampers the possibility for comparison of the facies found in the mirna lower valley with other river systems, where coarse particles are normally transported up to the bay head delta. the case of the mirna could be an example for other deltas developed in karstic environments, such as several examples along the eastern adriatic coast, where the supply of sands and gravels is poor. the information collected by this research also supports some considerations about past relative sea levels. the dated sample at 5.27 m in m2 (–2.87 m msl) corresponds to the base of a swampy environment that formed over estuarine deposits, and we interpreted it as the shift to freshwater conditions after the mirna river mouth (bay head delta) had passed downstream of the location of m2. the dated layer (–2.9 m, ~280 years ad) is a fairly good marker of the relative past sea level, because it formed in an environment close to sea level during late-antiquity (i.e., 3rd–4th century ad). for this marker we can assess a vertical error of about ±0.5 m with respect to the sea level existing during its deposition. in other sites in istria, the observed values of the relative roman sea level are generally between 1.9 and 1.6 m (antonioli et al., 2007), demonstrating that, at the site of core m2, quite strong subsidence has occurred since late-antiquity. as documented in the po delta and venetian plain (brambati et al., 2003; stefani & vincenzi, 2005), this process is consistent with the sedimentary compaction that in the last millennia could have occurred in the mirna valley in the lower estuarine and lagoonal deposits, due to the depositional load (over 5 m of silts and clays). moreover, reclamation activities could have also played a role, especially in the last century, inducing additional anthropogenic subsidence. the calibrated age obtained at 8.3 m in core m3 (1154– 1254 cal ad) is rather surprising for its young age and deep location (fig. 7), but it matches with the archaeological information available in the nearby chapel of s. maria of the bastia, where the layer of the 16th century is at 4.6 m depth (milotić & prodan, 2014). moreover, these data are comparable with the evolution that occurred in the upstream tract of the mirna river valley. as reported in faivre et al. (2011), historical documents recorded that, near motovun (montona) (fig. 1), in the 19th century, 0.80 m of alluvial deposits aggraded within 55 years and this huge depositional phase killed thousands of trees (morteani, 1895). moreover, in 1994 at the base of the hill of motovun, a trunk was found 4.5 m below the floor of the mirna river and its radiocarbon age was 1470–1600 ad (rubinić et al., 1999; prodan, 2001; milotić, 2004). the new data corroborate the evidence that, since the early middle ages, the evolution of the valley has been strongly influenced by human activity and, in particular by the exploitation of woods in the catchment. the operations of forest clearance exposed large areas of flysch, leading to widespread and rapid erosion. a huge quantity of fine sediment was available, overfeeding the mirna river flux and allowing the dramatic alteration of the valley floor topography and the fast progradation of the bay-head delta. especially intensive processes of sedimentation were occurring in the mirna river mouth, at the contact of marine saltwater and fluvial freshwater, by the process of flocculation which creates larger particles and the rapid sedimentation of transported material. these processes were also documented in the raša estuary where salt-induced flocculation is the dominant process in the sedimentation of fine-grained particles which are preferentially accumulated at the head of the estuary (sondi et al., 1995). from this perspective, the burial of the lagoon surface located at 2.5 m depth in m1 probably occurred after the roman period or even in the last centuries, when the mirna mouth prograded past this point. as documented along the opposite side of the adriatic, in the po and venetian-friulian plains (correggiari et al., 2005; cremonini et al., 2013; rossato et al., 2015), several flooding phases occurred since late antiquity with a peak during the early middle ages. these events, mainly related to atlantic atmospheric fronts, should also have partly influenced the istrian peninsula and, thus, we can suppose that depositional phases along the mirna river clustered in some periods as a product of the interplay between anthropogenic activities and peak flooding episodes. it is also worth noting that the occurrence of a phase with possible different environmental conditions from today before about 1000 ad was hypothesized as being responsible for the formation of the ne adriatic notches (furlani et al., 2011). 6. conclusions this research investigated the subsoil of the terminal tract of the mirna river valley using a multidisciplinary approach, combining lithological, sedimentological, geochronological and both macroand microfossil analyses. the mirna is the largest river of istria and one of the major water courses of the eastern side of the adriatic, therefore, the reconstruction of the environments which characterized this area (and their holocene evolution) can be an important reference for other fluvial systems along the eastern adriatic coast with karstic estuaries (eg. raša, krka, zrmanja, or neretva rivers). the important results achieved by this research can be briefly described as: i) in the studied area the late-holocene deposits consist almost entirely of fine grained sediments (i.e. silts and clays), often with a homogeneous appearance and, therefore distinction among the different sedimentary facies needs the use of palaeontological indicators. foraminiferal investigation was a strong tool, but the combined use with ostracod analysis could probably improve the detail in the results. ii) in the last 6500 years, a bay-head delta sequence prograded for over 7 km in the lower tract of the mirna river, filling the pre-existing valley with a sediment thickness of at least 13 m. in the cores the alluvial facies (a) were located above brackish swamps and hyposaline marshes (ba) while, below them, sediments related to the inner estuary/lagoon (bb) and outer lagoon/estuary (e) were present. felja et al.: environmental changes in the lower mirna river valley (istria, croatia) during the middle and late holocene geologia croatica 223 iii) the large and almost steady input of freshwater supplied by the river and some karstic springs in the lower valley contributed to lowering the salinity due to the protected setting offered by the bay, allowing the presence of an outerlagoon/estuary (e) assemblage even in front of the river mouth, instead of marine species. iv) since late antiquity an important alluvial phase started, leading to deposition of several metres of silty clay sediments that are thicker than 9 m in core m3. the sedimentary supply has been partly increased by forest clearance that occurred in the mirna catchment that was particularly severe during the 15–19th centuries. the huge quantity of fine grained alluvial deposits is related to the extensive outcrop of eocene flysch that is particularly prone to erosion and, thus, facilitated the rapid filling of the karstic valley and progradation of the bay head delta. v) the recent and strong sedimentary load accelerated compaction of the holocene deposits. this local subsidence also affected the relative sea level position that experienced a downshift of 2.9±0.5 m since the 2nd–3rd centuries ad. acknowledgment this research is part of the project sea-level variations and subsidence in northern adriatic in the last 130,000 years through geomorphological, stratigraphic and geoarchaeological indicators funded by the university of padova (progetto di ateneo cod. c91j10000320001, responsible a. fontana). this research was also supported by the croatian science foundation research project nanominerals in sediments and soils: formation, properties and their role in biogeochemical processes (hrzz 2504). this paper benefited from discussions with members of the project “medflood – mediterranean sea-level change and projection for future flooding “ (2012–2015), sponsored by inqua. valuable comments of reviewers g. sarti and j. rubinić significantly improved the final version of the article. the authors thank mrs. nataša klarić and her family for their logistic support during the field operations. references albani, a.d., serandrei–barbero, r. & donnici, s. (2007): foraminifera as ecological indicators in the lagoon of venice, italy.– ecological indicators, 7, 239–253. amorosi, a., colalongo, m.l., fiorini, f., fusco, f., pasini, g., vaiani, s.c.& sarti, g. (2004): palaeogeographic and palaeoclimatic evolution of the po plain from 150–ky core records.– global planetary change, 40, 55–78. amorosi, a., centineo, m.c., colalongo, m.l. & fiorini, f. (2005): millennial–scale depositional cycles from the holocene of the po plain, italy.– marine geology, 222–223, 7–18. amorosi, a., fontana, a., antonioli, f., primon, s. & bondesan, a. (2008): post–lgm sedimentation and holocene shoreline evolution in the nw adriatic coastal area.– geoacta, 7, 41–67. antonioli, f., anzidei, m., auriemma, r., gaddi, d., furlani, s., lambeck, k., orru’, p., solinas, e., gaspari, a., karinja, s., kovačić, v. & surace, l. (2007): sea level change during holocene from sardinia and northeastern adriatic from archaeological and geomorphological data.– quaternary science review, 26, 2463–2486. antonioli, f., amorosi, a., bondesan, a, braitenberg, c., dutton, a., ferranti, l., fontana, a., fontolan, g., furlani, s., lambeck, k., mastronuzzi, g., monaco, c. & orru’, p. (2009): a review of the holocene sea–level changes and tectonic movements along the italian coastline.– quaternary international, 206, 102–133. benac, č. & arbanas, ž. (1990): sedimentacija u području ušća rječine [the sedimentation in the area of the mouth of rječina river].– pomorski zbornik, 28, 593–609. benac, č., juračić, m. & bakran–petricioli, t. (2004): submerged tidal notches in the rijeka bay ne adriatic sea: indicators of relative sea–level change and of recent tectonic movements.– marine geology, 212, 21–33. benac, č., juračić, m. & blašković, i. (2008): tidal notches in vinodol channel and bakar bay, ne adriatic sea: indicators of recent tectonics.– marine geology, 248, 151–160. božičević, s. (2005): mirna.– in: bertoša, m. & matijašić, r. (eds.): istarska enciklopedija. [istrian enciklopedy]. leksikografski zavod miroslav krleža, zagreb, 493–494. brambati, a., carbognin, l., quaia, t., teatini, p. & tosi, l. (2003): the lagoon of venice: geological setting, evolution and land subsidence.– episodes, 26, 263–268. bronk ramsey, c. (2009): bayesian analysis of radiocarbon dates.– radiocarbon, 51/1, 337–360. carre, m.b., kovačić, v. & tassaux, f. (2007): quatre ans de recherche sur le littoral parentin.– in: auriemma r., karinja s. (eds.): terre di mare. l’archeologia dei paesaggi costierei e le variazioni climatiche. atti del convegno internazionale di studi trieste, 8–10 novembre 2007, trieste, 310–315. castellarin, a., cantelli, l., fesce, a.m., mercier, j.l., picotti, v., pini, g.a., prosser, g. & selli, l. (1992): alpine compressional tectonics in the southern alps. relationship with the n– apennines.– annales tectonicae, 6 (1), 62–94. castiglioni, g.b. (ed.) (1997): geomorphological map of po plain. murst–s.el.ca, 3 sheets, scale 1:250,000, firenze. cimerman, f. & langer, m. r. (1991): mediterranean foraminifera.– sazu, ljubljana, 119 p. correggiari, a., roveri, m. & trincardi, f. (1996): late pleistocene and holocene evolution of the north adriatic sea ii quaternario – italian journal of quaternary sciences, 9/2, 697–704. correggiari, a., cattaneo, a., trincardi, f. (2005): the modern po delta system: lobe switching and asymmetric prodelta growth.– marine geology, 222–223, 49–74. cremonini, s., labate, d. & curina, r. (2013): the late–antiquity environmental crisis in emilia region (po river plain, northern italy): geoarchaeological evidence and paleoclimatic considerations.– quaternary international 316, 162–178. croatian geological survey (2009): geological map of the republic of croatia 1:300000. – croatian geological survey, zagreb. debenay, j-p., tsakiridis, e., soulard, r. & grossel, h. (2001): factors determining the distribution of foraminiferal assemblages in port joinville (ile d’yeu, france): the influence of pollution.– marine micropaleontology, 43, 75–118. d’incà, c. (2007): il porto quieto e il fiume: un mutare di funzioni e di paesaggi tra l’istria costiera e l’interno.– in: auriemma, r. & karinja, s. (eds.): terre di mare. l’archeologia dei paesaggi costierei e le variazioni climatiche. atti del convegno internazionale di studi trieste, 8–10 novembre 2007, trieste, 400–406. donnici, s. & serandrei–barbero, r. (2002): the benthic foraminiferal communities of the northern adriatic continental shelf.– marine micropaleontology, 44, 93–123. faivre, s. & fouache, e. (2003): some tectonic influences on the croatian shoreline evolution in the last 2000 years.– zeitschrift für geomorphologie, 47/4, 521–537. faivre, s., fouache, e., ghilardi, m., antonioli, f., furlani, s. & kovačić, v. (2011): relative sea level change in istria (croatia) during the last 5 ka.– quaternary international, 232, 132–143. fao–isric (2006): guidelines for soil description, 4rd edition.– international soil reference information centre, rome, 97 p. geologia croatica 68/3geologia croatica 224 forenbaher, s., kaiser, t. & miracle, p. (2013): dating the east adriatic neolithic.– european journal of archaeology, 16/4, 589–609. furlani, s., cucchi, f., biolchi, s. & odorico, r. (2011): notches in the adriatic sea: genesis and development.– quaternary international, 232, 158–168. furlani, s., pappalardo, m., gomez–pujol, l. & chelli, a. (2014): the rock coast of the mediterranean and black seas.– in: kennedy, d.m., stephenson, w.j. & naylor, l.a. (eds.): rock coast geomorphology: a global synthesis.– geological society, london memoirs, 40, 89–123. gulam, v., pollak, d. & podolszki, l. (2014): the analysis of the flysch badlands inventory in central istria, croatia.– geologia croatica, 67/1, 1–15. hammer, o., harper, d. a. t &, ryan, p. d. (2001): past: paleontological statistics software package for education and data analysis.– paleontol. electron., 4, 1–9. igh (1994): probno ispitivanje pilota za viadukt preko doline rijeke mirne 2200–1–213255/94 [the preliminary testing of pilots for the viaduct over the mirna river valley].– zavod za geotehniku, institut građevinarstva hrvatske, 22 p., zagreb. loeblich, jr., a. r. & tappan, h., (1988): foraminiferal genera and their classification.– van nostrand, reinhold, new york, 970 p. + 847pls. magdalenić, a., vazdar, t. & hlevnjak, b. (1995): hydrogeology of the gradole spring draining area in central istria.– geologia croatica, 48, 97–106. mcrae, s. g. (1988): practical pedology: studying soils in the field.– ellis horwood, chichester, john wiley, london, 253 p. melis, r. & covelli, s. (2013): distribution and morphological abnormalities of recent foraminifera in the marano and grado lagoon (north adriatic sea, italy).– mediterranean marine science, 14/1, 432–450. miall, a.d. (1996): the geology of fluvial deposits: sedimentary facies, basin analysis and petroleum geology.– springer, berlin, 582 p. milotić, i. (2004): dolina mirne u antici [the mirna valley in ancient history].– ekološki glasnik, donja lomnica, 325 p. milotić, i. & prodan, l. (2014): stoljeće i pol organizirane vodoprivrede u istri [one and a half century of the organized water management in istria].– vodoprivreda d.o.o., buzet, 370 p. morteani, l. (1895): storia di montona [parte vi].– archeografo triestino, ii serie, vol. xx (xxiv), 410, 5–123. murray, j.w. (1974): distribution and ecology of living benthic foraminiferids.– heinemann educational books, london, 274 p. murray, j. (1991): ecology and paleoecology of benthic foraminifera.– longman scientific and technical, london, 397 p. murray, j.w. (2006): ecology and applications of benthic foraminifera.– cambridge university press, cambridge, new york, 426 p. ogrinc, n., faganeli, j., ogorelec, b. & čermelj, b. (2007): the origin of organic matter in holocene sediments in the bay of koper (gulf of trieste, northern adriatic sea).– geologija, 50/1, 179–187. ogorelec, b., mišić, m., šercelj, a., cimerman, f., faganeli, j. & stegnar, p. (1981): sediment sečoveljske soline [sediment of the salt marsh of sečovlje].geologija 24/2, 179-216. parentin, l. (1974): cittanova d’istria.– trieste, 303 p. pavelić, d., kovačić, m., vlahović, i., mandic, o., marković, f. & wacha, l. (2014): topography controlling the wind regime on the karstic coast: late pleistocene coastal calcareous sands of eastern mid–adriatic, croatia.– facies, 60, 843–863. péres, j.m. & picard, j. (1964): nouveau manuel de bionomiebenthique de la mer méditerranée.– rec. trav. stat. mar. endoume, 31, 137 p. pleničar, m., polšak, a. & šikić, d. (1965): osnovna geološka karta sfrj 1:100000, tumač za list trst, l33–88 [basic geological map of sfry 1:100000, geology of the trst sheet, l33–88].– geološki zavod ljubljana i institut za geološka istraživanja zagreb, 64 p. polšak, a.& šikić, d. (1963): osnovna geološka karta sfrj 1:100000, tumač za list rovinj, l33–100 [basic geological map of sfry 1:100000, geology of the rovinj sheet, l33–100].– institut za geološka istraživanja, zagreb, 47p. pikelj, k. & juračić, m. (2013): eastern adriatic coast (eac): geomorphology and coastal vulnerability of a karstic coast.– journal of coastal research, 29, 944–957 prodan, v. (2001): hidrografija sliva potoka butoniga [hydrography of the butoniga creek basin].– buzetski zbornik, 155–170. reimer, p.j., bard, e., bayliss, a., beck, j.w., blackwell, p.g., bronk ramsey, c., grootes, p.m., guilderson, t.p., haflidason, h., hajdas, i., hatté, c., heaton, t.j., hoffmann, d.l., hogg, a.g., hughen, k.a., kaiser, k.f., kromer, b., manning, s.w., niu, m., reimer, r.w., richards, d.a., scott, e.m., southon, j.r., staff, r.a., turney, c.s.m. & van der plicht, j. (2013): intcal13 and marine13 radiocarbon age calibration curves 0–50,000 years cal bp.– radiocarbon, 55, 1869–1887. retallack, g.j. (1990): soils of the past: an introduction to paleopedology. – unwin hyman, london, 520 p. rossato, s., fontana, a. & mozzi, p. (2015): meta-analysis of the holocene 14c database of the venetian-friulian alluvial plain (ne italy).– catena, 130, 34–45. rubinić, j., bušelić, g., kukuljan, i. & kosović, m. (1999): hidrološka analiza suspendiranog nanosa u istarskim vodama [hydrological analysis of suspended sediment in the istrian waters].– hrvatske vode, 7/27, 127–137. sakara sučević, m. (2004): prazgodovinska naselbina pri novi vasi, brtonigla (istra) [prehistoric settlement near nova vas, brtonigla (istria)].– univerza na primorskem, znanstveno-raziskovalno središče, inštitut za dediščino sredozemlja, koper, 205 p. santin, g.a. (2013): fiumi e torrenti dell’istria: caratteristiche e problematiche attuali.– d.i.g. vodoprivreda d.o.o. buzet, 12 p. scott, d.b. & medioli, f.s. (1978): vertical zonations of marsh foraminifera as accurate indicators of former sea-levels.– nature, 272, 528–531. soil survey staff (2003): keys to soil taxonomy. 9th edition.– usdanrcs, washington, 305 p. sondi, i., juračić, m. & pravdić, v. (1995): sedimentation in a disequilibrium river–dominated estuary. the raša river estuary (adriatic sea–croatia).– sedimentology, 42, 769–78. stefani, m. & vincenzi, s. (2005): the interplay of eustasy, climate and human activity in the late quaternary depositional evolution and sedimentary architecture of the po delta system.– marine geo logy, 222– 223, 19–48. tosi, l., carbognin, l., teatini, p., rosselli, r. & gasparetto stori, g. (2000): the ises project subsidence monitoring of the catchment basin south of the venice lagoon, italy.– in: carbognin l. et al. (eds.): land subsidence, vol. 2. la garangola, padova (italy), 113– 126. vaniček, v., juračić, m., bajraktarević, z. & ćosović, v. (2000): benthic foraminiferal assemblages in a restricted environment – an example from the mljet lakes (adriatic sea, croatia).– geologia croatica, 53, 269–279. velić, i., vlahović, i. & matičec, d. (2002): depositional sequences and palaeography of the adriatic carbonate platform.– memorie della società geologica italiana, 57, 141–151. vranješ, m., vidoš, d. & glavaš, b. (2007): stanje sedimenta u donjoj neretvi (status of sediments in the lower neretva river).– in: gereš, d. (ed.): 4 hrvatska konferencija o vodama. hrvatske vode i europska unija – izazovi i mogućnosti.– hrvatske vode, zagreb, 337– 344. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeography, palaeoclimatology, palaeoecology, 220, 333–360. vis, g.j., kasse, c. & vandemberg, j. (2008): late pleistocene and holocene palaeogeography of the lower tagus valley (portugal): effects of relative sea level, valley morphology and sediment supply.– quaternary science reviews, 27, 1682–1709. vis, g.j. & kasse, c. (2009): late quaternary valley-fill succession of the lower tagus valley, portugal.– sedimentary geology, 221, 19–39. manuscript received march 27, 2015 revised manuscript accepted september 16, 2015 available online october 31, 2015 gc_2-2013_kb.indd ab stra ct the activity concentrations and the distribution of manmade 137cs and naturally occurring radionuclides 40k, 238u and 232th in surface and core sediments of the semi-enclosed, river-dominated marine environment of the neretva channel were investigated in relation to the sedimentological characteristics and the total organic carbon (toc) content. the activity concentrations of radionuclides were determined by gamma spectrometry. distinct interrelationships between sediment properties and the spatial distribution of radionuclides were observed. the highest accumulation of 137cs occurs close to the river mouth, in the region of intensive deposition of organic matter of terrestrial origin. this discovery implies that the river-borne organic material and its deposition processes should be considered as the most important factor controlling distribution of 137cs in this transitional terrestrial-marine environment. sediment accumulation rates, estimated from the distribution of 137cs in core sediments, were approximately 6 mm y–1 in front of the neretva river mouth and 4 mm y–1 in the channel area. the spatial distribution of natural 40k and 232th radionuclides indicates their distinct association with fi ne-grained sediments. the interrelationship of 238u with fi ne-grained particles was somewhat weaker but still present. the results obtained indicate that the accumulation pattern of natural radionuclides in the neretva channel sediments is mainly governed by the deposition of fi ne-grained material. this study scrutinizes the baseline level for the occurring radionuclides and should be used for monitoring and assessing the radionuclide pollution record in the investigated transitional terrestrial-marine environment of the adriatic. keywords: radiomiclides, sedimentation rate, total organic carbon, fi ne-grained sediments, neretva channel  geologia croatica 66/2 143–150 4 figs. zagreb 2013 geologia croaticageologia croatica activity concentrations and distribution of radionuclides in surface and core sediments of the neretva channel (adriatic sea, croatia)  irena jurina1, maja ivanić1, tamara troskot-čorbić2, delko barišić1, neda vdović1 and ivan sondi3 1 division for marine and environmental research, ruđer bošković institute, zagreb, croatia 2 e&p research laboratory department, ina-oil industry plc., zagreb, croatia 3 faculty of mining, geology and petroleum engineering, university of zagreb, zagreb, croatia; (corresponding author: ivan.sondi@rgn.hr) doi: 10.4154/gc.2013.11 1. introduction environmental radioactivity has become a subject of scientifi c interest in recent decades, not only due to possible risks to human health, but also because radionuclides have been recognized as tracers of many complex biogeochemical processes (porcelli & baskaran, 2011). sediment erosion and accumulation rates or transport of elements to the oceans are only a few examples of processes where radionuclide monitoring has been applied. geologia croatica 66/2geologia croatica 144 the mobility of radionuclides in aquatic environments is governed by their geochemical characteristics, such as solubility, complexation ability and affi nity for adsorption onto mineral surfaces (chabaux et al., 2003). natural radionuclides, such as 238u, 232th and 40k, are released into the environment through erosion and chemical weathering of the radionuclide-bearing rocks, and are subsequently transported through surface and ground water systems (vigier et al., 2001). the fate of radionuclides in transitional terrestrial-marine and marine environments is mostly infl uenced by their interaction with clay minerals, organic matter and colloidal iron and manganese oxides and hydroxides (andersson et al., 2001; mckee, 2008). river-dominated coastal areas of the adriatic region are characterized by complex physico-chemical interactions and transformations of dissolved and particulate organic and inorganic compounds (sondi et al., 1994; sondi et al., 1995; sondi et al., 2008). in such environments, the transport and deposition of radionuclides is governed by dispersal processes affecting fi ne-grained sediments, direct precipitation of oxides and oxyhydroxides and coagulation of inorganic and organic colloidal materials (andersson et al., 1998; ligero et al., 2001). there are several anthropogenic sources of radionuclides whose contribution to overall environmental radioactivity cannot be neglected. major sources of radioactive contamination include the nuclear weapons program, nuclear power plants, uranium mining and milling, commercial fuel processing and nuclear accidents (hu et al., 2010). the anthropogenic release of radionuclides into the environment includes both natural and manmade isotopes, such as 137cs. once introduced into the environment, these radionuclides are affected by the same processes as other components of the natural systems. however, due to their known source, they often provide a recognisable imprint in the environment which facilitates the identifi cation of processes and changes occurring in natural ecosystems. in that context, the natural radionuclide 40k and manmade 137cs were used as tracers of sediment transport and sedimentation dynamics in a river-dominated karstic estuary in the north-eastern adriatic (sondi et al., 1995). it was shown that the highest activity concentrations of these radionuclides occur at the river mouth in accordance with the prevalent sedimentation of clayey particles associated with terrestrial organic matter. petrinec et al. (2012a) investigated the activity concentrations of manmade 137cs and natural radionuclides 40k, 226ra, 228ra and 238u in seawater and sediments at several locations along the eastern adriatic coast – from piran bay to the otranto strait. they discovered signifi cant correlations between the activity concentrations of 40k, 228ra and 238u and sedimentological characteristics, suggesting that variability in radionuclide activity concentrations can be explained by differences in the mineral composition of the sediments. distribution of 137cs activity concentration in core sediments was used to estimate sediment accumulation rates at several locations in the middle and south adriatic sea. a sedimentation rate of ~ 1.8 mm y–1 was reported for deposits from the south adriatic pit, while albanian offshore shelf sediments had a much higher accumulation rate of ~ 4 mm y–1 (petrinec et al., 2012b). sediment accumulation rates of approximately 1 to 5 mm y–1 were also reported at different locations in the krka river estuary (cukrov et al., 2007). in addition, cukrov et al. (2009) illustrated that diverse natural sources of sediments can only partially explain the variations in activity concentrations of 238u and 226ra, and that signifi cant anthropogenic input of radionuclides can be observed in the area close to the town of šibenik. this paper reports on a study of the activity concentrations of 137cs, 40k, 238u and 232th radionuclides in the sediments of the neretva channel. in particular, it reports on the accumulation patterns of these radionuclides in surface and subsurface sediments and the sediment accumulation rates based on vertical distributions of the 137cs activity concentration. finally, it addresses the geochemical behaviour of the investigated radionuclides through their association with organic and inorganic compounds in a semi-enclosed and river-dominated coastal environment of the adriatic region. 2. study area the neretva channel is an isolated, narrow part of the adriatic sea, semi-enclosed by the pelješac peninsula on the southern side. the surrounding area is mainly karstic terrain, consisting of jurassic and cretaceous limestones and dolomites with some occurrences of triassic limestones, eocene limestones and fl ysch (fig. 1). the channel itself is a microtidal, low-wave energy environment characterised by river-dominated sedimentation processes (jurina et al., 2010). the neretva river enters the channel on its northern side; it is the largest river on the croatian part of the eastern adriatic coast, and the only one forming a deltaic system. the river is approximately 255 km long with a catchment area of about 13000 km2. in the upland part of the river basin, the river drains a heterogeneous terrain characterised by several geological units: triassic and miocene clastic sedimentary rocks, triassic volcanic rocks and volcano-sedimentary series, a mesozoic carbonate succession, and cretaceous fl ysch (mojićević & laušević, 1973a; mojićević & laušević, 1973b; sofilj & živanović, 1980; mojićević & tomić, 1982). most of the sediment load carried by the river originates from the fl ysch and clastic deposits exposed at the surface in this area. the estimated annual sediment discharge in 2000 was 13.58 x 106 tons (eurosion, 2004). the lowland part of the neretva river is only 36 km long and fl ows through quaternary alluvial deposits. average annual water discharge is 332 m3s–1 with peaks in december and april (orlić et al., 2006). 3. methods 3.1. sampling and sampling preparation the fi eld surveys in the neretva channel were conducted in october 2009 and june 2010. three undisturbed sediment jurina et al.: activity concentrations and distribution of radionuclides in surface and core sediments of the neretva channel (adriatic sea, croatia) geologia croatica 145 cores up to 35 cm long were retrieved at stations k1–k3 (fig. 1). at an additional 28 stations (marked as dotted grid in fig. 1) only the uppermost 5 cm of core sediments (surface sediments) were collected. all sediment samples were retrieved using a gravity corer (uwitec, austria), were frozen immediately after sampling and kept at –20°c. prior to analysis, frozen sediment cores from stations k1–k3 were cut into 5 cm segments, after which the sediments were freeze dried (freezone 2.5, labconco, usa) and homogenized. 3.2. analyses sediment samples were granulometrically characterized by the laser diffraction particle size analyzer (ls 13 320, beckman coulter, usa). one gram of dry sample was suspended in 50 ml of redistilled water and placed in an ultrasound bath for 3 minutes. approximately 5 to 10 ml of the suspension obtained was placed in a dispersion unit cell and analysed. no surfactants were used. particle size was calculated on a volume basis using the mie theory. samples were measured in triplicate and the average particle size distribution spectra were taken as results. the clay-silt-sand ratios of the sediments were determined according to the modifi ed wenthworth scale (1922) with the clay-silt boundary at 2 μm. the total organic carbon (toc) content of the sediments was determined by combustion of acid insoluble matter in a leco ir–212 carbon analyser (usa), after treatment with hot 1:1 diluted 36.5% hcl. gamma-spectrometry measurements were conducted using a low-background hyperpure germanium (hpge) “canberra” semiconductor detector system coupled to an 8196-channel analyzer (meriden, usa). prior to measurement, sediment samples were oven dried at 105° to constant weight. the expanded uncertainty of measurements are stated as the standard uncertainty of measurement multiplied by the coverage factor k = 2, which for a normal distribution corresponds to a coverage probability of 95%. 3.3. calculation pearson correlation coeffi cients were calculated using statistica for windows ver. 7.0 (statsoft inc., usa). contour maps were constructed using surfer 8 (golden software, usa) with kriging as an interpolation method. figure 1: geological map of the neretva channel showing the study area and sampling stations. legend: 1– quaternary alluvial deposits; 2 – eocene fl ysch; 3 – eocene limestones; 4 – cretaceous limestones and dolomites; 5 – jurassic limestones and dolomites 6 – triassic limestones. geologia croatica 66/2geologia croatica 146 4. results and discussion 4.1. granulometric and mineralogical characteristics of sediments considering the ratio of different grain size fractions (shepard, 1954), surface sediments from the neretva channel were classifi ed as clayey silts (fig. 2). the signifi cant amount of sand fraction (64 %) was only observed in the sample collected in the vicinity of the small islet located in the southern part of the investigated area (fig. 1). there were no signifi cant changes in granulometric characteristics in the core sediment samples. the spatial distribution of the fi ne-grained particles, i.e. mud (< 63 μm), in the surface sediments is presented in figure 3. it is important to note that the predominant accumulation of fi ne-grained particles occurs in north-western part of the investigated area, toward the exit from the neretva channel. such an accumulation pattern is in accordance with the observed water circulation, where a hypopycnal river plume formed at the mouth distributing fi ne-grained particles over the channel area and toward the open sea. the mineral composition of all the investigated surface sediments was similar. samples were mainly composed of calcite, quartz, feldspars, dolomite and a signifi cant amount of clay minerals, particularly illite (jurina et al., 2010). 4.2. distribution of radionuclides in surface sediments the results of the present study provide a good example of the distribution of radionuclides in a semi-enclosed fl uviomarine environment of the adriatic region. the two dominant processes identifi ed as the most important factors governing the deposition of radionuclides in surface sediments of the neretva channel, were the sedimentation of fi negrained material and deposition of the river-borne terrestrial organic matter. the distribution of 137cs in surface sediments of the neretva channel is shown in figure 3. the activity concentrations varied from 3.7 ± 1.1 to 13.7 ± 2.1 bq kg–1. the highest values were found close to the river mouth and decreased seaward. a similar distribution pattern was observed for toc, with values ranging from 0.29 to 0.98 % and the highest values being determined in the area close to the neretva river inlet (fig. 3). this suggests a close association of 137cs with sedimentary organic matter. the obvious unknown is the mechanism governing the depositional pattern of the toc and how this process infl uences the distribution of 137cs in the surface sediments of the neretva channel. we may speculate that the coagulation and deposition of terrestrial dissolved and particulate organic matter in the freshwaterseawater mixing zone results in scavenging of this radionuclide from the water column and its fi xation in the seabed sediments. the importance of organic matter for 137cs accumulation in marine sediments was previously reported by rubio et al. (2003) and ligero et al. (2001). correlation between the 137cs activity concentrations and the toc content (r = 0.45, p < 0.05) in the neretva channel sediments is in agreement with those observations. river-borne organic material is mainly composed of humic and fulvic acids which are shown to coagulate even at low salinities (sondi et al., 1996; sondi et al., 1997; sondi et al., 1998). consequently, pronounced deposition of terrestrial organic matter occurs in mixing zones, close to the river mouth, as observed in the neretva channel sediments. the toc content decreases seaward indicating the reduced fl uvial infl uence and probably more pronounced accumulation of marine organic matter in the sediments. the activity concentrations of 137cs in the surface sediments of the neretva channel were found to be higher than those in sediments from the southern adriatic region (0.8 – 3.8 bq kg–1, petrinec et al., 2012a). this can be attributed to the considerable load of 137cs in the neretva river discharge processes. previous measurements of the 137cs activity concentrations in the raša river estuary also revealed a high accumulation at the river mouth, indicating that fl uvial discharge should be considered as the main source of 137cs in the coastal environment of the adriatic region (sondi et al., 1995). the lowest measured activity concentrations of 40k and 232th were 350.3 ± 44.1 bq kg–1 and 19.8 ± 5.0 bq kg–1, respectively. the spatial distribution of these two radionuclides displayed a similar accumulation trend. in addition, a strong positive correlation (r = 0.76, p < 0.001) occurs between these two radionuclides, indicating their close association. high activity concentrations, up to 647.6 ± 74.6 bq kg–1 for 40k and 34.2 ± 6.3 bq kg–1 for 232th, were observed in surface sediments containing a high percentage of fi ne-grained particles (fig. 3). the correlation coeffi cients between 40k and 232th activity concentrations and mud content in surface sediments of the neretva channel are 0.41 (p < 0.05) and 0.48 (p < 0.01), respectively, suggesting the important role of fi ne-grained particles in the transport and deposition of figure 2: ternary diagram for the classifi cation of sediments (shepard, 1954) with samples from the study area denoted on the basis of the obtained sand/silt/clay ratios. jurina et al.: activity concentrations and distribution of radionuclides in surface and core sediments of the neretva channel (adriatic sea, croatia) geologia croatica 147 232th and 40k in the sediments of the neretva channel. regarding the 40k behaviour, this radionuclide is very soluble and easily incorporated into the clay mineral crystal lattice, particularly in the interlayer sites of an illite-type structure. thorium isotopes are considered insoluble in cation form (th4+) but can be mobilised through complexation with organic and inorganic ligands (langmuir & herman, 1980). after entering the surface waters, th is easily adsorbed onto mineral surfaces, particularly fe oxyhydroxides (andersson et al., 1995). accordingly, the close association of 232th and 40k in the surface sediments of the neretva channel could be a consequence of their mutual inorganic carriers. the transport of both radionuclides is governed by their binding to the clay mineral surfaces and/ or co-precipitated fe oxide and oxyhydroxide coatings. therefore, the accumulation of these radionuclides in the neretva channel area is governed by fi ne-grained sediment deposition processes. the activity concentrations of 238u in surface sediments from the neretva channel varied from 17.5 ± 9.8 to 46.1 ± 14.2 bq kg–1. association of this radionuclide with sedimentary organic matter in the neretva channel sediments was not observed, although many studies report organic phases as being important carriers of 238u in river and brackish waters (andersson et al., 1998). correlation between 238u and 232th activity concentrations (r = 0.51, p < 0.01) suggests that the distribution of these radionuclides in the neretva channel sediments is at least partially governed by the same processes. indeed, an increase of 238u activity concentrations was observed in the area characterized by the accufigure 3. distributions of mud and toc content and 137cs, 40k, 238u and 232th activity concentrations in the surface sediments of t he neretva channel. geologia croatica 66/2geologia croatica 148 mulation of fi ne-grained particles, although there was no signifi cant correlation between 238u and the mud content of sediments. the somewhat different distribution of 238u in the neretva channel surface sediments could be explained by desorption of this radionuclide from its organic and inorganic carriers. in the coastal mixing zones, fl uvial sedimentary material enters an environment of increased alkalinity. this enhances the formation of uranyl carbonate complexes and results in remobilization of uranium (langmuir, 1997). the high activity concentration of 238u (490 bq m–3) discovered in the seawater in ploče harbour (petrinec et al., 2012a) is in agreement with the proposed desorption behaviour of uranyl species. the mean activity concentration of 40k (526 bq kg–1) in the surface sediments of the neretva channel is signifi cantly higher than the world average value of 370 bq kg–1 (unscear, 1988). the high content of fi ne-grained particles in the neretva channel sediments, the abundance of clay minerals, particularly illite, can partially explain the elevated activity concentrations of 40k. however, the neretva river delta plain, which is adjacent to the study area, is an important agricultural region. considering that 40k activity concentrations as high as 6500 bq kg–1 have been reported in phosphate fertilizers (khater & al-sewaidan, 2008), their extensive use in the delta plain may be a signifi cant source of 40k radionuclide in the neretva channel sediments. the specifi c activities of natural radionuclides 238u and 232th in surface sediments of the investigated area did not vary signifi cantly. in comparison, the study in the nearby krka river estuary reported activity concentrations from 14.1 ± 2.5 to 485 ± 16 bq kg–1 for 238u (cukrov et al., 2009). the town of šibenik, located in the krka river estuary, is the main croatian port for phosphate ore transhipment, so localized anthropogenic input of 238u explains the wide range of values observed across the estuary. in the neretva channel, anthropogenic input of 238u and 232th radionuclides appears to be less pronounced. the mean values of 238u and 232th activity concentrations in surface sediments of the neretva channel are 31 bq kg–1 and 26 bq kg–1, respectively. these values are comparable to the world average value of 25 bq kg–1 reported for these two radionuclides (unscear, 1988). similar activity concentrations for 238u (28 bq kg–1) and 232th (21 bq kg–1) were also reported in the venice lagoon (desideri et al., 2001). the use of fertilizers in the adjacent agricultural region of the neretva river delta plain may contribute to slight enrichment in the neretva channel sediments of the 238u and 232th radionuclides. 4.3. distribution of radionuclides in core sediments the distribution of 137cs in core sediments from stations k1–k3 is presented in figure 4a. at station k1, activity concentrations of 137cs were constant (~ 9 bq kg–1) in the uppermost 12.5 cm of the sediment strata. the values started to decrease in deeper sediment layers and reached 0 bq kg–1 at 32.5 cm depth. the nuclear weapon testing and the subsequent atmospheric fallout of the 137cs radionuclide reached its maximum around 1963. the quantities of 137cs deposited in sediments prior to this were small and have been continuously reduced by radioactive decay up to the present day. for example, the amount of 137cs deposited in 1954 was reduced to half by 1984, and is reduced to about one quarter of the initial quantity by 2013. the detection limit of the gamma spectrometer used in this study was 0.3 bq kg–1 for 137cs. ritchie & mchenry (1990) argued that the determination of 137cs near the detection limits can cause inaccuracies in establishing the onset of accumulation. the quantity of this radionuclide deposited in the neretva channel sediments prior to the fallout maximum in 1963 was probably insuffi cient to be still reliably detectable. therefore it is assumed that 1963 is taken as the onset for accumulation of 137cs in sediments and the sedimentation rate at station k1 is estimated to ~ 6 mm y–1. at stations k2 and k3 the activity concentration of 137cs became undetectable at 22.5 cm depth. an estimated sedimentation rate at both stations is ~ 4 mm y–1. the difference in the sedimentation rate between stations k1–k3 is due to their varying distances from the neretva river mouth. it is expected that more sediment is deposited at station k1 located in front of the neretva inlet, than at stations k2 and k3 which are in the central channel area. nevertheless, considering the uncertainties of the measurements and estimated sedimentation rate, the observed difference of 2 mm y–1 is small. these results imply the signifi cance of the fl uvial input of sediments to the entire investigated area. figure 4. activity concentrations distributions in the sediment cores from stations k1−k3: a) 137cs, b) 40k, c) 238u, d) 232th. jurina et al.: activity concentrations and distribution of radionuclides in surface and core sediments of the neretva channel (adriatic sea, croatia) geologia croatica 149 the vertical distribution of 137cs at station k2 was similar to the vertical distribution of this radionuclide at station k1; the maximum activity concentration was found at the surface (7.2 ± 1.5 bq kg–1) and values continuously decreased with depth. at station k3, the maximum activity concentration of 137cs (5.9 ± 1.0 bq kg–1) was observed at 12.5 cm sediment depth. this increase was attributed to the chernobyl nuclear accident which occurred in 1986. the sedimentation rate, calculated based on this peak position, is ~ 4 mm y–1, which is in agreement with the previously estimated sedimentation rate based on the onset of 137cs accumulation. the reason why this peak was only observed at station k3 is somewhat unclear. it is possible that disturbance of the sediments by bioturbation or some other process was less pronounced at station k3 than in other areas of the neretva channel which allowed preservation of this distinct 137cs enrichment. the vertical distribution of 40k, 238u and 232th activity concentrations are presented in figure 4b–d. the activity concentrations of these three radionuclides in the core sediments were similar at all three sampling stations. values ranged from 537.7 ± 62.6 to 689.6 ± 74.6 bq kg–1 for 40k, from 21.9 ± 6.7 to 41.5 ± 11.0 bq kg–1 for 238u and from 25.3 ± 5.3 to 43.2 ± 6.4 to 43.2 ± 6.4 bq kg–1 for 232th. the vertical profi les of 40k, 238u and 232th activity concentrations revealed a similar accumulation pattern in core sediments for all three radionuclides, particularly at station k3. considering the observed similarities in the temporal accumulation pattern of 238u, 232th and 40k, depth variations in these radionuclides activity concentrations can be attributed to differences in grain-size and mineralogy of the deposited sediments. the only signifi cant difference in the vertical accumulation trend of these radionuclides is an increase in 238u activity concentration observed in surface sediments at station k2. this increase could be due to the penetration of seawater enriched with soluble 238u in the surface sediment layers at this sampling station (papaefthymiou et al., 2007). an alternative explanation is differential bioturbation rates between the investigated stations. there are two mechanisms through which bioturbation processes can promote uranium release from sediments to the water column (zheng et al., 2002). bioturbation can oxygenate sediment and/or stir them up, closer to the water-sediment interface. since uranium is subject to remobilisation in oxidising conditions, either of these scenarios can be the explanation for the lower activity concentration of 238u in surface sediments at stations k1 and k3. if bioturbation is less pronounced at station k2, removal of 238u radionuclide from surface sediments layers should not occur. 5. conclusions 1. the highest accumulation of 137cs occurred close to the river mouth, in the region of intensive deposition of organic matter of terrestrial origin, with amounts decreasing progressively seaward. 2. the sedimentation rates from 4 – 6 mm y–1 were estimated based on 137cs distribution in the core sediments. 3. the distribution of natural radionuclides 40k, 238u and 232th follows the accumulation pattern of the fi ne-grained sediment particles. this implies fi ne-grained sediment dispersal processes as the dominant factor governing the accumulation trend of these radionuclides. 4. signifi cant enrichment of 40k in the neretva channel sediments could be explained by the use of fertilizers in the neretva delta agricultural region, but further investigations are required. anthropogenic input of 238u and 232th appears to be negligible. acknowledgment this work was supported by the ministry of science, education and sports of the republic of croatia (grant 098-0982934-2742). the authors gratefully acknowledge the assistance of momir milunović and srečko karašić during fi eld surveys. references andersson, p.s., porcelli, d., gustafsson, ö., ingri, j. & wasserburg, g.j. (2001): the importance of colloids for the behavior of uranium isotopes in the low-salinity zone of a stable estuary.− geochim. cosmochim. acta, 65, 13−25. doi:10.1016/ s0016-7037(00)00514-7 andersson, p.s., porcelli, d., wasserburg, g.j. & ingri, j. (1998): particle transport of 234u–238u in the kalix river and in the baltic sea.− geochim. cosmochim. acta, 62, 385−392. doi:10.1016/s0016-7037(97)00342-6 andersson, p.s., wasserburg, g.j., chen, j.h., papanastassiou, d.a., & ingri, j. (1995): 238u–234u and 232th–230th in the baltic sea and in river water.− earth planet. sci. lett., 130, 217−234. doi:10.1016/0012-821x(94)00262-w chabaux, f., riotte, j. & dequincey, o. (2003): u-th-ra fractionation during weathering and river transport.− in: bourdon, b., henderson, g.m., lundstrom, c.c. & turner, s.p. (eds.): uranium series geochemistry. rev. mineral. geochem., 22, 533−576. doi:10.2113/0520533 cukrov, n., barišić, d. & juračić, m. (2007): calculated sedimentation rate in the krka river estuary using vertical distribution of 137cs.− rapp. comm. int. mer. medit., 38, p. 81. cukrov, n., mlakar, m., cuculić, v. & barišić, d. (2009): origin and transport of 238u and 226ra in riverine, estuarine and marine sediments of the krka river, croatia.− j. environ. radioactiv., 100, 497−504. doi:10.1016/j.jenvrad.2009.03.012 desideri, d., meli, m.a., roselli, c., testa, c. & degetto, s. (2001): speciation of natural and anthropogenic radionuclides in different sea sediment samples.– j. radioanal. nucl. ch., 248, 727−733. eurosion (2004): living with coastal erosion in europe: sediment and space for sustainability, part ii maps and statistics.− dg environment ec, brussels, 25 p. hu, q.-h., weng, j.-q. & wang, j.-h. (2010): sources of anthropogenic radionuclides in the environment: a review.− j. environ. radioactiv., 101, 426−437. doi:10.1016/j.jenvrad.2008.08.004 jurina, i., ivanić, m., vdović, n., mikac, n. & sondi, i. (2010): mechanism of the land-sea interactions in the neretva river delta (croatia): the distribution pattern of sediments and trace elements.− rapp. comm. int. mer. medit., 39, p. 35. khater, a.e.m. & al-sewaidan, h.a. (2008): radiation exposure due to agricultural uses of phosphate fertilizers.− radiat. meas., 43, 1402−1407. doi:10.1016/j.radmeas.2008.04.084 geologia croatica 66/2geologia croatica 150 langmuir, d. & herman, j.h. (1980): the mobility of thorium in natural waters at low temperatures.– geochim. cosmochim. acta, 44, 1753−1766. doi:10.1016/0016-7037(80)90226-4 langmuir, d. (1997): aqueous environmental geochemistry.− prentice hall, new jersey, 600 p. ligero, r.a., ramos-lerate, i., barrera, m. & casasruiz, m. (2001): relationships between sea-bed radionuclide activities and some sedimentological variables.− j. environ. radioactiv., 57, 7−19. doi:10.1016/s0265-931x(00)00213-7 mckee, b.a. (2008): uand th-series nuclides in estuarine environments.− in: krishnaswami, s. & cochran, j.k. (eds.): uth series nuclides in aquatic systems. elsevier, oxford, amsterdam, 193−225. mojićević, m. & laušević, m. (1973a): osnovna geološka karta 1:10000, list mostar, k33-24 [basic geological map of sfry 1:100000, moatar sheet – in croatian].− savezni geološki institut, beograd. mojićević, m. & laušević, m. (1973b): osnovna geološka karta 1:10000, list nevesinje, k34-25 [basic geological map of sfry 1:100000, nevesinje sheet – in croatian].− savezni geološki institut, beograd. mojićević, m. & tomić, b. (1982): osnovna geološka karta 1:10000, list kalinovik, k34-12 [basic geological map of sfry 1:100000, kalinovik sheet – in croatian].− savezni geološki institut, beograd. orlić, m., beg paklar, g., pasarić, z., grbec, b. & pasarić, m. (2006): nested modeling of the east adriatic coastal waters.− acta adriat., 47 (suppl.), 219−245. papaefthymiou, h., papatheodorou, g., moustakli, a. christodoulou, d. & geraga, m. (2007): natural radionuclides and 137cs distributions and their relationship with sedimentological processes in patras harbour, greece.– j. environ. radioactiv., 94, 55−74. doi:10.1016/j.jenvrad.2006.12.014 petrinec, b., štrok, m., franić, z., smodiš, b. & pavičićhamer, d. (2012a): radionuclides in the adriatic sea and related dose-rate assessment for marine biota.– radiat. prot. dosim., 148, 1–11. doi:10.1093/rpd/ncs234 petrinec, b., franić, z., ilijanić, n., miko, s., štrok, m. & smodiš, b. (2012b): estimation of sedimentation rate in the middle and south adriatic sea using 137cs.− radiat. prot. dosimetry, 151, 102−111. doi:10.1093/rpd/ncr449 porcelli, d. & baskaran, m. (2011): an overview of isotope geochemistry in environmental studies.– in: baskaran, m. (ed.): handbook of environmental isotope geochemistry.– springer, heidelberg, dordrecht, london, new york, 11−33. ritchie, j.c. & mchenry, j.r. (1990): application of radioactive fallout cesium-137 for measuring soil erosion and sediment accumulation rates and patterns: a review.− j. environ. qual., 19, 215−233. doi:10.2134/jeq1990.00472425001900020006x rubio, l., linares-rueda, a., dueñas, c., fernández, m.c., clavero, v. niell, f.x. & fernández, j.a. (2003): sediment accumulation rate and radiological characterisation of the sediments of palmones river estuary (southern spain).− j. environ. radioactiv., 65, 267−280. doi:10.1016/s0265-931x(02)00102-9 shepard, f.p. (1954): nomenclature based on sand-silty-clay ratios.− j. sediment. petrol., 24, 151–154. doi:10.1306/d4269774-2b2611d7-8648000102c1865d sofilj, j. & živanović, m. (1980): osnovna geološka karta 1:10000, list prozor, k34-25 [basic geological map of sfry 1:100000, prozor sheet]. − savezni geološki institut, beograd. sondi, i., juračić, m., prohić, e. & pravdić, v. (1994): particulates and the environmental capacity for trace metals. a small river as a model for a land-sea transfer system: the rasa river estuary.− sci. tot. env., 155, 173–185. doi:10.1016/0048-9697(94) 90290-9 sondi, i., juračić, m. & pravdić, v. (1995): sedimentation in a disequilibrium river-dominated estuary: the raša river estuary (adriatic sea, croatia).− sedimentology, 42, 769–782. doi:10.1111/ j.1365-3091.1995.tb00408.x sondi, i., bišćan, j. & pravdić, v. (1996): electrokinetic of pure clay minerals revisited.− j. colloid interf. sci., 178, 514–522. doi:10.1006/jcis.1996.0146 sondi, i., milat, o. & pravdić, v. (1997): electrokinetic potentials of clay surfaces modifi ed by polymers.− j. colloid interf. sci., 189, 66−73. sondi, i. & pravdić, v. (1998): the colloid and surface chemistry of clays in natural waters.− croat. chem. acta, 71, 1061−1074. sondi, i., lojen, s., juračić, m., & prohić, e. (2008): mechanisms of land-sea interactions – the distribution of metals and sedimentary organic matter in sediments of a river-dominated mediterranean karstic estuary.− estuar. coast. shelf s., 80, 12−20. doi: 10.1016/j.ecss.2008.07.001 unscear (1988): sources, effects and risks of ionizing radiation. annex a: exposures from natural sources of radiation.− united nations, new york, 134 p. vigier, n., bourdon, b., turner, s. & allègre, c.j. (2001): erosion timescales derived from u-decay series measurements in rivers.− earth planet. sci. lett., 193, 549−563. doi:10.1016/s0012821x(01)00510-6 wenthworth, c.k. (1922): a scale of grade and class terms for clastic sediments.− j. geol., 30, 377−392. zheng, y., anderson, r.f., van geen, a. & fleisher, m.q. (2002): remobilization of authigenic uranium in marine sediments by bioturbation.− geochim. cosmochim. acta, 66, 1759−1772. doi:10.1016/s0016-7037(01)00886-9 manuscript received march 19, 2013 revised manuscript accepted april 25, 2013 available online june 19, 2013 geol. croat. zagreb 1996 professional paper some experience with drilling and use of horizontal wells and way of their application in croatian hydrocarbon reservoirs ivo steiner' and boris burger' proceedings key words: horizontal wells, geologica l structures, bha. mwd, lwd, well completion. abstract in many hydrocarbon reservoirs hori zontal well paths enable (he more economical extraction of oil and gas than with venical wells in lhe same reservoirs. this is especially truc for cases of by-passed oil in partially depicted reservoirs. successful design ,md drilling of hori­ zontal wells is made possible by detailed knowl edge orthe geologicul structure, together with up-l o-dale geo physical anc! olher data. the drilling and production of lhe firs! horizontal well in croatia arc dis­ cussed and analysed. methods for drilling and completion of horizon­ tal wells, together with a proposa l for thei r global utilization, are pre­ sented, 1. introduction rccent technology facilitating the direction control of ihe borehole path enables the positioning of a wejl from any starti ng point on the surface (or subsurface) to any dcsired point in the subsurface providing it is with­ in the technical capabilities of thc available drilling rig and drill tools (steiner & boskov steiner. 1994). sueh wells consisl of: a vertical section; a build-up (curved) section, and a horizontal or extended-reach section. the drilling or horizontal wells, i.e. those wells the final part of whose has a horizontal path, has become a routine operation for which the following arc prerequi­ si tes: a) a good knowledge of the geological structure of the drilled area, particularly of the target layer, its over­ laying and underlying strata (solomon et ai., 1994; west & bodnar, 1994); b) 10 havc a corresponding bottom hole asscmbly (b ha) at disposal (agavani el ai. , 1994; rafie el ai., 1986); i faculty of mining, geology and petroleum engineering of the uni­ versity of zagreb, pierot1ijeva 6, iir-j 0000 zagreb, croatia. ~ ina-naftilplin. subiccva 29, hr 10000 zagreb, cro<llia. kljucnc rijeci: vodoravne busoiine, geoloske strukture, sklop alatki na dnu busotine, telemetrija , geolo­ gometrija, opremanje busotina. sazetak voc!oravni kanali bllsotina omogllcavaju u mnogim iclistimh ekorlomic niji dohvat nafte i plina od uspravnih busotin<l, a osobito dohvat zaos tale nafte ii djelomicno iscrpljcnim !czistima. dobro poz­ navanjc gco ioskc grade, dopllnjeno svrhovi toltl primjenorn suvfc ­ menih geofizickih i ostalih dostignllca, omogucava uspjesno projekti­ ranje i izvedbu vodoravnih busotina. r<lzmalraju sc isku stva izrade i uporabe prve vodoravne bllsotine u hrv alskoj, ic se , llsporedbom sa svje lskim iskustvima, prcdlazu nacini izrade dalj njih tak vih busotina, njihovo opremanje i uporaba. c) to have corresponding measuremcnt while drilling (mwd), and logging while drilling (l wd) equip­ ment al disposal (anon., 1993; tanguy & zoeller, 1981; hansen & wh ite, 1991); d) to have a well equipped drilling rig (if possible, with a top drive, a circulating elevator, etc.) for smooth drilling of the curved and horizontal part of the well (steiner & boskov steiner, 1994); e) to have a well designed and well equipped system for drilling fluid circulation and control (a linear shale shaker, centrifuges, etc.) and an adequate drilling flu ­ id , as e.g. a polymer drilling fluid. polymer fluids have good rheological properties, they thoroughly clean the borehole channel of rock cuttings, and they prevent settling of those cuttings. these fluids form a thin, tough filter cake on borehole walls which pro­ tects the productive zone from infiltration or the drilling fluid. this cake has a good lubricating prop­ erty and can be removed easily by a later realized nuid depression on the permeable and porous st rata (steiner & boskov steiner, 1994). naturally, selection of an adequate drilling fluid, pumping rates , control of torque and drag of the drill string and casing, blowout prevention and other factors affect the safe and effective drilling and these should not be neglected. the adequate completion of drilled horizontal wells is evcn more complex (austin el ai. , 1988; lessi & spreux, 1988). long-term and adequalely high pro­ duction of hydrocarbon f luids (oil and/or gas) from a horizontally drilled reservoir can be ensured by the right choicc and qualitative realization of well comple­ tion. this is especially true in the case where some by­ passed oil or gas arc targets (moiiamad & sni­ lder, 1986). the most inexpensive and in some cases sufficiently productive methods of completion are an open hole, and landing a slotted uncemented liner (as in the okoli horizontal well). however in heterogeneous layers, as is the case for most of the targets in croatia, such solu­ tions may cause undesired mixing of oil, gas and/or water (kriloy ct ai., 1996). such mixing may mini­ mize or even cause cessation of the expected fluid pro­ duction. sophisticated and relatively inexpensive com­ pletion methods of horizontal wells are available, and these may eliminate stich problems (duda & yost, 1995; bradick. 1993). primarily, horizontal and er (extended reach ::: nearly horizontal) wells arc drilled in reservoirs having: low permeability and/or problems with water or gas coning and/or low thickness of the pay zone and/or secondary permeability (fractures or fissures). 2. prerequisite geological data before producing a design for a horizontal well and defining it s radius or curvature, build-up rate, kick-off point, placement of tangent(s), etc. it is necessary to consolidate all the available data from vertical or devi­ ated wells in the region of the planned well. geologists and geophysicists familiar with the area should be includcd into the team which is preparing and control­ ling the drilling and completion of a horizontal well. all availablc data on thc geological structure and geo­ physical surface measurement of the location have to be studied and any missing measurements (such as 3d seismic etc.) have to be obtained and analysed (skopec, 1993; lamus para, 1992). in the case of the okoli horizontal well the analysis was not based on a 3d seismic survey, but only on a 2d seismic study, together with detailed knowledge of the okoli ficld and past experience o f similar scenarios. in addition to extensive knowledge of the expected gcological facies it is important to know thc rock stability and existing vertical restrictions inside the target reservoir. there are technical rcstrictions in obtaining large rock cuttings and core from the horizontal part or the well. therefore cllllings and cores from nearby vertical or less deviated wells have 10 be used for analyses (kriloy et ai., 1996). a lot of valuable data can be obtained in real-time by l \vd measurement, before seriolls formation dam­ age has begun. comparison of these data with data obtaincd after the drilling is completed can give indica­ tions concerning the effective stimulation of future fluid production (la yne & yost, 1994). geologia croatica 49n 3. bottom hole assembly a number of particular too ls used for dba (bottom hole assembly) exists, designed for deviated and/or [or straight sections of horizontal wclls. these arc subs. stabilizers, rdm (positive displacement motors) , non­ magnet ic drill collars, flexible drill pipes, etc. for those operators who drill only a few horizontal wells the best solution is to rent a service from one or the service companies specializing in horizon tal drilling or to rent only the necessary parts of an adequate biia from them. in this example a medium radius build-up rate of 3°/10 m having a radius of250 m and a lateral deviation or 290 m were chosen. for such a job an accustomed drill string may be used without flexible drill pipe and other sophisticated tools. computer models aiding the optimal choice of the bi-ia exist (birades, 1986; kikuci-il, 1993). recently, horizontal wells are often drilled with rigs having coiled-tubing as a part of the drill string (wu & juvkam-wold, 1993; edge et ai., 1994). even though voluminous and expensive cquipment is neces­ sary for drilling with coiled-tubing, it has the distinct advantage of shortening the time for round-trips which decreases the cost of horizontal drilling. coiled-tubing and handling equ ipment can be rented at a reasonable price from companies producing them. 4. mwd and lwd in order to correctly drill a horizontal well it is essential lo have data on the azimuth and dip angle of the well path . collection of such dala in real-time enables the necessary corrections 10 be made by chang­ ing weight on the bit, bit rotation, bit face position etc. if data is obtained by mud pulses, which is the most widely used met hod, the necessary corrections on the hole bottom are limited, since there is only a one-way communication from the bi-ta toward the surface. in the application of mud pulsing signals there is a need for a homogenous, continuos fluid column in the drill string through which pulses are transported. if underbalanced drilling, with aerated drilling fluid or air drilling is applied, mud pulses cannot be trans­ ported crom the bha 10 the surface. tn the case of infill wells toward by-passed oil and/or gas, it is often advis­ able to apply underbalanced drilling. signals crom the bra can be transported by electromagnetic waves wherc the circuit is formed from the transmitter at the bi-ia through drilled rocks to the receiver on the sur­ face and backward through the drill string. signals can bc sent in two directions, one carrying data from the bha and the other carrying commands from the sur­ face allowing change to the parameters at the bha. electromagnetic mwd/lwd has to be taken seri­ ously as a convenient alternative in horizontal drilling for by-passed oil and/or gas and in drilling of re-entries in reservoirs with depleted pressure. sicincr & burgcr: somc expc ricnce with drilling and use of ilorizonial wells ... diameter diameter planned realized (mm) (inch) (m) (m) sor.o 20 100 iii 339.7 133/r 1800 1898 244.5 95/8 2360 2311 177.8 7 2350-2860 2280-2442 177.8 7 2243-2268 137 5 2268-2892 5. completion ii' ihere is any reason ror avoiding simple solutions such 3s an open hole completion or landing of a slotted liner without packing , stich as heterogeneous layers with variable oil , water and gas saturation, various per­ meability, pressure differences in drilled rocks in the horizontal part of the well , loose sand ctc. it is advi s­ able to apply designs with inflatable packers, partial cementing, grave l packing and/or with slotted liner hav­ ing s lidin g ports. for more effect ive drainage of a drilled reservoir a multi-branch completion may be an effective solution (steiner & boskov-steiner. 1994). as the purchase and landing of liners with existing sophi st icated completion methods is a very expensive and complex venture, it should be thoroughly analysed whether the invested amount o/" money can be covered by the value of increased production. 6. okoli well the first horizontal well in croatia the okoli field is a gas and gas condensate produc­ ing field siluated in the sava trench, the most southern part of the pannonian basin. tn tertiary sed iments there are three productive reservoir-series: a, band c. the a-series is closest to the surface. it was depict­ ed until a pressure grad ient of .44 bar/l 0 m was reached. 11 is now serv in g as a subsurface gas store (sgs ). when it is filled with stored gas the pressure gradient is elevated to .94 bar/io m. when the vertical part of the horizontal well was dril led through thi s se ri es the pressure gradient was at the highest level. the b-se ries is in production and its pressure gradi­ ent varies between .31-.33 bar/l 0 ill. the c-series reservoir, which was the target of the hori zontal well, is an anticline consisting of a number of thin , sandstone deposits characterised by low-penne­ abi lity and interlayered with non-permeable shale. the horizontal well path is si tuated on the top o/" the anti­ cline with its lateral part following the crest o/" the elon­ gated anticline. the pressure gradient in the c-series varies between .45-.90 bar/lo m. the aim of the first horizontal well in croatia was to inc rease gas production from a low permeability, thin remark covered sgs" many differ. stuck pipe stuck-liner 101 table 1 planned and realized casing program okoli horiwlllal well. • sgs = subsu rfac e gas storage. layer reservoir (so called sandwich st ru ct ure) and to prove whether a horizontal well is able to produce al least 1.5 times the volume of gas per day than thal of a vertical well stimulated by hydraulic fracturing in the same reservoir. therefore a thorough study was under­ taken with a calculated four year period for return of the investment. taking into consideration the available tools , equip­ ment and fin ancial resource, the tna -naflaplin compa­ ny decided to drill a hor izontal well into the okoli gas bearing c-series from a kick-ott-point at 1,925 m. it was planned to case the lateral section (of about 500 ill) with a slotted liner or 7 inch diameter and 10 cover 110n­ stable reservoir rock with that liner. the okoli horizon­ tal well casing program is shown in table i. rea lization of the curved and horizontal part of thi s first horizontal well in croatia was entrusted 10 an experienced in te rnational servi ce company. the aim was to include a partner able to offer an integrated ser­ vice which would help in drilling, well completion and commission ing of the horizontal well. due to low pressure gradients the underbalanced drilling method was considered. however operating company did not have the necessary equipment. rent­ ing of such equipment and expense of purchasing nec­ essary material meant that the expected financial resuil from well production would be lower than the financial inves tment req uired and this method was therefore abandoned. the gas reservoir of the b -series is located in the build-up section of the well. sillee the pressure gradient in this series is low (.31-.33 bar/lo 111) and the polymer drilling fluid had a density of 1.050 kg/m ' . il was expected to get stuck pipe due to dil1erential pressure. but since the filter cake was f ~ttty and slippery this was expected to be miti ga ted. however due to frequent sticking pipe it was decided to switch from a slidin g mode to rotary mode, which caused the build -up rate (bur) to be losl. drilling was stopped and it was decided to co ntinue with a small er bit diameter and with a more flexible drill string, in order to retrieve back the desired bur. at a depth of 2,311 m a 9 5/8 inch diameter casing string was landed and cemented. when the final length of the hole at 2,900 m was achi eved , an attempt had been made to land a slotted liner of 7 inch diameter. this li ner was equipped with a wash pipe in case the liner became stuck so that, by cir302 culation and by applying the driller's method, the liner may be freed. the slohed liner was also equipped with spiral, rigid blade centralizers. during running of the liner it became stuck when its casing shoe was at 2,472 m (161 m beyond the previous casing). the wash pipe failed. a top drive, a power swivel and/or circulating elevator were not available. by pulling it, the liner was made free, and when pulled for about one pipe stand, at a length of 2,442 m it became stuck again (a centralizer stuck in the shoe of the 9 5/8 inch casing string). this problem was solved by cutting the 7 inch liner at 2,280 ill, 3 1 m above the shoe of the 9 5/8 inch diamctcr cas­ ing. the free part of the 7 inch liner was pulled out of the hole. after drilling through the bottom assembly of the 7 inch pipe the hole was completely cleaned, fol­ lowing which a 5 inch slotted liner wilh a wash pipe at the shoe and no cent ralizers, was run lo the well bot10m. a liner hanger, prepared for the 7 inch liner, was adapted with a 7x5 inch joint and was used for fixing the 5 inch liner to the previous casing stri ng. the well was finished according to the designed tra­ jectory and generally completed accord ing to the designed casing program, with cxeeption of the substi ­ tution of a 5 inch liner instead of the designed 7 inch one. it was accomplished according to the predicted time schedule, except of an additional len days spent for fishing job. according to laboratory tests with core from a simi ­ lar reservoir (kriloy et al, 1996) it is es timated that a formation damage of 33% of the original permeability exists, caused by the applied polymer drilling fluid and a synthetic formation water. this test may bc repeated sincc core exists from the same reservoir and formation water from it may be collected. production equipment with a permanent packer and a 3 1/2-inch tubing was run and sat isfactory gas produc­ tion has been achieved. the horizontal well has attained following production: a) 500% higher production than that of an average ver­ tical , unstimulated wel! from the same reservoir; b) 180% higher production than that from a vertical well in the samc reservoir which was stimulated by hydraulic rracturing. purchase of equ ipmcnt and tools needed for the lat­ e ral interval or the well requi red approximately 6% of the total cost of the well. service cos ts (special tools and equipment, mwd and their handling) have amounted to about 8% of the total drilling costs. for various materials 45 % o/" that cost was needed and 55% was paid to the service company. the horizontal wej[ was in toud 44% more expensive than an average verti­ cal we ll or the same length. the cost per meter of the drilled horizontal well was approx im atcly 900 usd. in the horizontal part of the borehole no classical wcll logging was done as it were no t needed and the equipment and tools required such as carriers and joints with side door opening for entrance of the cable were unavailable. geologiil crojticil 49/2 workover in the hori zontal part of the we!! could not be performed either as there were no adequate coiled tubing and necessary lools available. application of ecp-s (external casing packers) was not planned because they arc too expensive in comparison with cal­ culated value of producable gas and because the equip­ ment for activating such packers was unavailable. con­ sequently , no stimulation job can be performed in this borehole because no section surrounding the borehole can be isolated. 7. conclusions globally the appl ication of horizontal wells for increasing the hydrocarbon fluid production from other­ wise inaccess ible or poorly accessible reservoirs has become an everyday practice in the world, and thou ­ sands of such weljs are drilled annually. in the search for by-passed oil and/or gas and for their production horizontal wells are the most effective means. in croa­ tia we can expect a reasonable quantity of by-passed oil and/or gas in a number of previollsly discovercd and non -rationall y depleted reservoirs as wei! as in the vicinity of more recently discovered ones. th ere is a necd to study each of the existing reservo irs and estab­ lish whether horizontal wells would help finding exist­ ing by-passed oil and/or gas and increasing the oil and gas production. without a decision to drill significantly more hori­ zonta l wells in a short period there is no reason to pur­ chase or produce special equipment and tools for hori­ zontal and/or er-drilling. it is more reasonablc to hire specia lized serv icc companies with good references who arc able to offer a reasonable price of serv ice in fair competition. acknowledgment this paper is based on work sponsored by the croa­ tian-am eri can joint fund in cooperation with the us deparlment or energy under project jf no. 278. 8. references agavani, m., rahman, s.s. & maidla, e.e. (1994): a new approach to selecting optimum bot ­ tom hole assembly configuration for any given well trajectory.spe asia pacific oil and gas confer­ ence. spe paper 28774,9 p., melbourne. anon. ( 1993): state od the art in mwd.2ndedit., inti' mwd society. houston, 32 p. austin, c.. zimmerman. c., sullaway. b. & sabins, r. (1988): fundamentals of horizon ta l well completion. drilling, may-june, 28-31. birades. m. (1986): orphee 3d: static and dyna­ mic threedimensional bha computer models.61 til steiner & 13urger: some experience wi th drilling and use of horizontal wells ... annual tech. coni". and exhib. of the spe, spe paper 15466, new orleans, 12 p. bradlck, b. ( 1993) : vizszintes kutkikepzesi modsz­ erek.koeolaj es foeldgaz, 25(125)/7, 207-210. duda , j.r. & yost, a.b. (1995): doe/fossil ener­ gy's drilling, completion and stimulat ion r&d : a techno logies/products overview.spe eastern regional cant". and exhib" spe paper 30993, mor­ gantown, 16 p. edge, e., !lrinkhorst, j. , voelker , [-i., !lur­ ge, p. & even, r.t. (1994): funhcr advances in coilcd-lurbing drill ing.europec, spe paper 28866, london, 9 p. ha ns en, r.r. & white, j. (1991): reatures in log­ g in g-w hilc-d rilling (lwd) in horizontal wells.­ spe/jadc dril ling conkrcnce, spe paper 21989, amsterdam , 9 p. kikuch[, s. (1993): 2d & 3d planning for horizontal wells.spe middle east oil tech. coni. and exhib., !lahrain , spe paper 25647, 15 p. kr[lov, z., wojtanowicz, a.k. & tom[c, m. (1996) : formation damage in horizonta l wells caused by polymcr mud. spe formation damage symposiulll, spe paper 31135, lafayette, 16 p. lamus para , a.u. (1992): operational geological experiences of hori zontal wclls.sccond latin american petro l. eng, coni". (ii lapec) of the spe, spe paper 23654, caracas, l i p. layne, a.w. & yost, a.b. ( 1994): development of advanccd drilling, completion and stimulation sys­ tems for minimum formation damage and improved e lticicncy: a program overview. spe inti ' symp. on form . dam., spe paper 27353, la f"ayette, 7 p. less[, j. & spreux, a. (1988): complet ion ochori­ zon tal clrainho les .s pe meeting on petrol. eng., spe pape r 17572, tianjin, 10 p. 303 mohamad, a.y. & snljder, g.t. (1986): identifi ­ cation of bypassed oil usmg gamma-ray spectrometty tool in old wclls. spe offshore south east coni". and exhib. , spe paper 14604, singapore, 10 p. r afie, 5., ho, h.-s. & chandre, u. (1986): appli­ cation of a dha analysis program in dircction drill ing. spe/iadc drill ing confcrence, spe paper 14765, dallas, 10 p. skopec, r.a. (1993): characterization in reservo irs targeted for horizontal drilling.jollr. pel. tcch., 1168-1176, spe paper 22709. solomon, s.t., ross, k.c. , burton, r.c. & welborn, j.e. (1994): multidiseiplined approach to designi ng targcts for horizontal wells. jour. pet. tech., 143-149, spe paper 25506 . steiner, i. & boskov steiner, z. (1994): tchnologija vodoravnoga buscnja. barbat, zagreb, 170 p. tanguy, d.r. & zoeller , wa (1981): applica­ tions of measuremcn t whi le drilling. 56111 annua l fall techn. conl and exhib. of the spe, spe paper 10324, san antonio, 16 p. west, c.c. & bodnar, da (1994): reviewal' the geological environment for horizontal we lls. sec­ ond arch ie colloqu ium, spe paper 23544, ho us­ ton, 10 p. wu, j. & juvkam-wold, h.c. (1993): drilling and completing horizonta l wells with coiled tubing. 681h annual tech. conf. and exhib. , spe paper 26336, houston, 17 p. 30-1 geologia owl1 ic;, 49j2  geochemical characteristics of thermal waters of hrvatsko zagorje  tamara marković, staša borović and ozren larva croatian geological survey, department of hydrogeology and engineering geology, sachsova, 2, zagreb, croatia; (tmarkovic@hgi-cgs.hr; sborovic@hgi-cgs.hr; olarva@hgi-cgs.hr) doi: 10.4154/gc.2015.05 abstract in the region of hrvatsko zagorje there are a lot of spa localities. the study area is in the northern pannonian part of croatia which is characterized by a high geothermal gradient (0.049 °c/m) and surface heat flow (76 mw/m2). although there are a lot of thermal occurrences in the study area, only ten were taken into consideration because there was a lack of geochemical data at other locations. the thermal springs considered are: harina zlaka, krapinske toplice, tuheljske toplice, stubičke toplice, sutinske toplice, šemničke toplice, topličica (mađarevo), topličica (gotalovec), podevčevo, vraždinske toplice. a compilation of geochemical data from different sources together with our own measurements has been used in this study. the aim of this paper is to review the thermal waters’ geochemical characteristics and demonstrate how these features can be used to discern their origin and the aquifer they equilibrated with. the geochemical characteristics of thermal waters of the study area suggest that the water is in equilibrium with dolomite which means that dolomite is the thermal aquifer in the study area. keywords: thermal water, groundwater temperature, chemical composition, water type, hrvatsko zagorje 1. introduction hot water occurring at the earth’s surface has been a subject of awe since the dawn of humankind. ancient civilizations revered thermal springs because they were believed to have supernatural and healing powers (routh et al., 1996; lamoreaux & tanner, 2001). thermal waters are increasingly being used in the world for industrial processing, agriculture production, heating, electricity production and the extraction of rare elements (atkinson & davidson, 2002; hellman & ramsey, 2004; petraccia et al., 2005; lund, 2006; haehnlein et al., 2010). moreover, with the increasing popularity of spas and the growing importance attached to the ‘natural’ health industry, thermal waters are becoming a valuable asset for centres of hydrotherapy (routh et al., 1996; lund, 1996; marović et al., 1996; harvey, 2007; bituh et al., 2009). thermal waters are thus a natural resource that could make considerable contribution to the local and regional economy. however, care should be exercised when making decisions regarding the appropriate use of thermal waters. croatia is relatively richly endowed with thermal waters and their utilization has been a tradition for millennia. hrvatsko zagorje is a region situated in the north-western part of central croatia (fig. 1). it stretches between the croatian-slovenian borderline and the medvednica and kalnik mountains. most of the region is characterized by undulating relief, especially the foothills of ivanščica mt., populated since antiquity. a “corrugated relief” with multiple interconnected mountains and valleys has always been an obstacle for the construction of meaningful transport networks in the area. the region sees a daily workforce migration to the national capital zagreb, but it is also a traditional recreational area for many citizens of zagreb, who visit its numerous spa resorts (roglić, 1974). the number of spa localities in hrvatsko zagorje is high, and they are densely distributed across the region. the simple indicator of this situation is the sheer number of toponyms „toplica“ (singular) or „toplice“ (plural), meaning thergeologia croatica 68/1 67–77 7 figs. 2 tabs. zagreb 2015 geologia croaticageologia croatica geologia croatica 68/1geologia croatica 68 mal water spring(s), and „topličica“ meaning little thermal water spring (with little referring to the lower temperature of the water, not its quantity). some of the localities were utilized even in prehistoric time, and in ancient roman time they were already established as curative destinations, especially aquae iassae (varaždinske toplice) with it’s numerous upright archaeological remains and aquae vitae (krapinske toplice). even the roman name of the pannonian tribe populating this area (lat. iassi) is derived from the supposedly curative properties of thermal waters because the root iasor iat-came from the ancient greek language meaning to heal or cure (schejbal, 2003). the temperatures of the thermal waters in hrvatsko zagorje vary from 16 to 65 °c. there are many available scales to classify thermal resources and thermal springs. according to all of the geothermal resource classifications (e.g. axelsson & gunlaugsson, 1978; muffler & cataldi, 1978; ungemach & economides, 1987; benderitter & cormy, 1990; hochstein, 1990; nicholson, 1993; sanyal, 2005) these resources at hrvatsko zagorje are considered low enthalpy resources. due to their relatively low temperatures, the classifications for thermal springs are more appropriate. these classifications vary significantly, because they use different benchmark values for identifying cold, warm and hot springs. it is common to classify the springs as warm if their temperature is lower than that of the human body, and hot if it is higher (e.g. deming, 2002; krešić, 2010). some authors have also considered the lower boundary for classifying waters as thermal, taking e.g. 20 °c which is a limit for balneological purposes (haramustek et al., 1952; iveković & peroš, 1981) or the temperature which disables ice formation at the rim of the spring, around 15 °c (đurović, 1960). from the hydrogeological point of view however, all groundwaters with temperatures higher than the average rainwater temperature (approximately the mean annual temperature of the locality) are considered thermal, although they cannot be used in balneology. since the climate of the investigated region is cfwbx’’ according to the köppen classification (gajić-čapka & zaninović, 2008) – a temperate (c) humid (f) climate with no extremely dry periods throughout the year, and the annual mean temperature of the region varies between 7–8 °c at the highest mountains and 10–11 °c in the valleys (gajićčapka & zaninović, 2008) – in a hydrogeological sense all groundwaters with temperatures higher than this average are considered thermal. in this paper the waters have been categorized according to the modified balneological classification (tab. 1). it was created on the basis of the traditional croatian balneological classification (haramustek et al., 1952), which actually stemmed from much earlier considerations of german and swiss medical balneology experts (jacobj, 1907; hintz & grünhut, 1916; hartmann, 1925). the modification was applied to the lower part of the scale, thus including the waters where the temperature is higher than the annual mean, but lower than that required in balneology. figure 1: the location of the hrvatsko zagorje region in croatia. table 1: categorization of thermal localities in croatia on the basis of water temperature (adopted from kovačić & perica, 1998). category subthermal hypothermal homeothermal hyperthermal temperature 13–20 °c >20–34 °c >34–38 °c >38 °c marković et al.: geochemical characteristics of thermal waters of hrvatsko zagorje geologia croatica 69 the waters considered here range from subthermal to hyperthermal. the modes of utilization vary according to the temperatures, e.g. waters of the lowest temperatures are used for the public water supply, bottling and fish farming, while waters of the highest temperatures (40–65 °c) are utilized for water and space heating. according to its geothermal characteristics, croatia can be divided into two parts where the mean values of the important geothermal parameters vary significantly. the northern pannonian part is characterized by a high geothermal gradient (0,049 °c/m) and surface heat flow (76 mw/m2), while the southern dinaric part has a low average geothermal gradient (0,018 °c/m) and surface heat flow (29 mw/ m2) (bošnjak et al., 1998). in accordance with these characteristics, many locations where thermal springs exist are located in the northern part of croatia where the groundwater receives enough heat from its surroundings. attempts to explain the appearance and origin of the thermal springs in croatia date back as far as the 18th century. many geologists at those times were studying the warm springs of hrvatsko zagorje owing to their unusual density in the region, and they postulated a number of different hypotheses to explain their occurrence. for example, in the beginning of 20th century dragutin gorjanović-kramberger was convinced that the thermal waters of north-western croatia were of volcanic origin with magma chambers heating the waters and deep faults, so called “thermal lines”, bringing them to the surface. the main shortcoming of this hypothesis is that there are no recent magmatic bodies to supply heat, but because of gorjanović-kramberger’s authority it still has a fair number of supporters (šimunić, 2008). the idea that thermal waters could be of meteoric origin and then heated during circulation through the subsurface first appeared in the works of gjuro pilar at the end of 19th century and is still supported by all the evidence. until now, it has been proven that all significant thermal springs in the pannonian part of croatia are located in the tops of anticlines which were fractured by faults of sw – ne or n – s strike. the intersections of faults and folds usually represent a strongly fractured environment of high permeability which enables the upwelling of heated water at depth to the surface (šimunić, 2008). the geochemical studies of horvatinčić et al. (1991; 1996) proved that the thermal waters of the hrvatsko zagorje area are of meteoric origin. in other papers, the geochemical characteristics of some springs in the research area have been studied and all data point to a meteoric origin (miholić, 1940a, 1952, 1959; marović et al., 1996; marković & kovačić, 2006; bituh et al., 2009; polančec, 2011). the aim of this paper is to review the thermal waters’ geochemical characteristics and demonstrate how geochemical features of thermal waters can be used to discern their origin and the aquifer they equilibrated with. although there are lots of thermal occurrences in the study area, only ten were taken into consideration because there was a lack of geochemical data at other locations. the thermal springs considered are: harina zlaka, krapinske toplice, tuheljske toplice, stubičke toplice, sutinske toplice, šemničke toplice, topličica (mađarevo), topličica (gotalovec), podevčevo and vraždinske toplice (fig. 2). 2. hydrogeological settings in harina zlaka (fig. 2) there was a natural thermal spring with a water temperature of 32.8 °c (miholić, 1940a). the spring dried up after 1966, following exploitation of thermal water from the well on the opposite bank of the sutla river for the atomske toplice spa in podčetrtek, slovenia. the figure 2: locations of the thermal springs described in the paper. geologia croatica 68/1geologia croatica 70 well is drilled in the carbonate sediments (dolomites). in 1998, near the dried up spring, the well hzl-1 was drilled, also in dolomites. it has been tested with a yield of 45 l/s, and the water temperature at the wellhead was 19–20 °c (mraz & krsnik, 2005). thermal springs of krapinske toplice (fig. 2) occur in a narrow valley of the topličica stream and there are three main springs and a few springs of lower yield. the main occurrence of thermal springs is in the area of pučke and jakobove kupelji. the total measured yield of all springs in krapinske toplice, according to bać & herak (1962), ranges from 69 to 81 l/s. the majority of springs occur along the boundary between the dolomite and limestone. in 1985 a deep well was drilled about 250 m north from the thermal springs. the well passed through limestone and dolomite before it ended up in calcarenites and shale at a depth of 861 m (šimunić, 1986). the well was tested with a yield of 30 l/s and the water temperature was 45 °c. thermal waters in krapinske toplice are used for recreation, balneotherapy, space heating and sanitary water. tuheljske toplice springs (fig. 2) are located nearby at the krapinske toplice thermal water source, 4.5 km to the southeast. the surrounding area of tuheljske toplice consists of limestone, dolomite, sandstone, marl, clay, gravel and sand. thermal springs are ascending springs and they occur in several places, from which the most important are the dadino vrelo and vrelo u bari springs. the total yield of the thermal springs was 85 l/s (bać & herak, 1962) and the temperature varies from 32.5 to 33.1 °c. these thermal waters have so far only been used for recreational purposes. stubičke toplice springs (fig. 2) are located on the northern side of medvednica mt. they had consisted of two major and several smaller springs, but they dried up when deep wells were drilled and put into operation. spring water temperature varied from 30 to 49.8 °c and the water in the wells has a temperature of 65 °c. the yield of the springs was 18 l/s (bać & herak, 1962). the surrounding area of the stubičke toplice springs comprises clastic carbonate sediments, dolomite, alluvial, proluvial-deluvial deposits and siliciclastic rocks. today thermal water from the wells is used for recreation, balneotherapy, water and space heating, sanitary water and greenhouse heating, and it is the locality with most diversified utilization of geothermal waters in croatia (borović & marković, 2015). thermal springs of sutinske toplice (fig. 2) are located in the canyon of the sutinska stream. water temperature ranges from 30 to 37.4 °c and the water emerges from fractured dolomites. in 1988 a well was drilled in the southern exit of sutinska canyon and a dolomite aquifer was detected in the interval between 75 – 385 m. a pumping test was carried out resulting in a yield of 112 l/s and the water temperature at the wellhead varied from 38 to 39 °c (britvić, 1988). the water had been used for a swimming pool during the summer, but it was closed in the summer of 2013. the šemničke toplice springs (fig. 2) are located near to the krapinske toplice thermal water source, 9 km to the northwest. the yield of the thermal spring is 0.5-1.0 l/s and the water temperature ranges from 31 to 33.1 °c. the well was drilled in the vicinity of the springs and carbonates were found. the well was pumped with the yield of 20 l/s, and the water temperature varied from 33 to 36oc (capar, 1982). the thermal water of šemničke toplice is not currently being utilized. the topličica springs in mađarevo (fig. 2) occur at the foot of the steep slopes of the ivanščica massif near novi marof. there are four major springs and several smaller ones. the water temperature is inconsistent: during the summer it varies from 18 to 22.5 °c, and during winter temperatures are lower. significant fluctuations in temperature and yield indicate mixing of cold and thermal water. the total yield of all the springs has not been measured. thermal water is used for heating a fish farm nearby and for recreation in the summer. the topličica spring in gotalovec (fig. 2) is located on the southern slopes of the central part of the ivanščica massif. the yield of the spring ranges from 15 to 18 l/s and the water temperature is from 25 to 26 °c. the spring occurs at the contact between the fractured dolomite aquifer and eruptives and clastic sediments. the water is being used for bottling as natural spring water. in podevčevo (fig. 2) there are two thermal springs, with variable temperatures, from 16.3 to 20.0 °c depending on the hydrological cycle. the aquifer is fractured dolomite. the total yield of both springs does not exceed 1 l/s. the springs are not used. varaždinske toplice springs (fig. 2) are located in the north-eastern corner of the study area, nearby the town of varaždin. they are among the best known, are the largest spas in croatia and have been used for the longest time. the water temperature varies from 56.5 to 57.5 °c and the yield ranges from 45 to 50 l/s. the thermal waters occur in the brecciated dolomites which are covered by clastic sediments (šimunić, 2008). the largest spring in varažidnske toplice is klokot, accompanied by three smaller hypothermal springs with temperatures of 24–25 °c. there are also a lot of wells. thermal waters from the spring and wells are used for recreation, balneotherapy, water and space heating (borović & marković, 2015). 3. materials and methods a compilation of geochemical data from different sources has been used in this study, including chemical analyses by miholić (1952) and juršić-mitrović (2001), and chemical analyses performed during research for the basic hydrogeological map sheets rogatec and varaždin in october 2009. from a total of 32 analyses, 10 analyses were performed by miholić (1952), 10 by juršić-mitrović (2001) and 12 analyses were performed in the scope of the research for the basic hydrogeological map. the samples taken during research for hydrogeological map were analysed at the hydrochemical laboratory of the department of hydrogeology and engineering geology of croatian geological survey. prior to sampling, the electrical conductivity (ec), ph and temperature (t) were determined using portable wtw probes. total alkalinity was measured by titramarković et al.: geochemical characteristics of thermal waters of hrvatsko zagorje geologia croatica 71 table 2: mean, minimum and maximum values of physicochemical parameters in observed thermal waters. harina zlaka krapinske toplice tuheljske topliice stubičke toplice sutinske toplice šemničke toplice topličica mađarevo topličica gotalovec podevčevo varaždinske toplice ec(ms/cm) mean min max 635 597 655 519 438 566 623 620 627 627 610 653 515 510 520 532 522 545 568 539 596 422 403 440 675 672 678 1206 1176 1235 t(°c) mean min max 24.2 19.8 32.8 41.8 40.2 45.0 32.8 32.5 33.1 53.9 47.0 65.0 34.9 34.0 35.7 32.7 32.5 33.1 23.0 22.5 23.4 25.6 25.5 25.7 17.7 16.0 19.4 54.2 51.2 57.2 ph mean min max 7.4 7.4 7.5 7.1 7.0 7.3 7.3 7.3 7.4 7.0 6.7 7.3 7.2 6.9 7.5 7.4 7.4 7.5 7.3 7.3 7.3 7.3 7.2 7.3 7.8 7.6 8.0 6.7 6.6 6.8 na+(mg/l) mean min max 7.2 2.8 14.0 11.4 9.1 17.0 11.3 10.9 11.8 25.3 20.8 28.5 5.0 3.8 6.2 9.7 6.3 11.8 3.2 2.4 4.0 4.3 3.4 5.2 26.1 22.6 29.6 86.2 76.8 95.6 k+(mg/l) mean min max 2.3 2.0 2.9 3.3 2.8 3.5 3.0 2.9 3.1 6.3 4.6 7.3 1.7 1.6 1.8 3.0 2.9 3.1 1.6 0.9 2.2 1.9 1.0 2.8 9.4 9.3 9.6 32.1 23.2 40.9 ca2+(mg/l) mean min max 68.7 61.9 75.3 54.9 52.4 58.2 63.8 63.2 64.6 66.9 61.0 71.7 65.2 53.7 76.6 61.5 57.6 63.7 62.3 53.7 70.9 60.9 55.8 65.9 58.8 56.6 60.9 126.2 125.1 127.3 mg2+(mg/l) mean min max 36.0 31.8 44.1 30.7 27.8 35.1 36.9 34.9 38.0 25.4 23.1 30.2 29.8 26.6 33.0 39.0 37.9 41.0 30.4 26.8 33.9 24.7 21.6 27.8 32.8 29.6 36.0 28.3 27.3 29.2 hco3 – (mg/l) mean min max 362.0 333.8 407.5 296.3 280.6 330.9 367.9 364.8 371.0 281.8 262.3 300.4 288.1 288.0 288.2 355.6 330.9 371.0 328.2 298.0 358.3 292.1 288.2 296.0 341.3 338.0 344.7 454.4 445.3 463.5 so4 2– (mg/l) mean min max 25.7 15.6 39.7 37.3 35.3 39.7 37.6 35.2 39.4 88.3 80.2 97.9 31.3 27.9 34.8 40.6 38.2 44.2 20.6 15.8 25.4 14.7 13.1 16.3 71.0 61.9 80.0 168.6 155.8 181.5 cl–(mg/l) mean min max 7.7 3.4 10.7 3.1 2.5 3.7 3.5 2.6 5.0 12.1 9.6 13.9 3.9 1.5 6.2 3.6 2.6 5.3 3.4 3.1 3.7 6.1 5.9 6.4 14.3 12.5 16.2 82.8 79.0 86.6 number of samples 3 5 3 4 3 3 3 3 2 3 tion with 1.6 n h2so4 using phenolphthalein and bromcresol green – methyl red as indicators. anions (so4 2and cl-) were measured by ion chromatograph (laballiance ltd) and dissolved cations (na+, k+, mg2+ and ca2+) by atomic absorption spectrophotometer (perkin elmer analyst 700). the netpath-win program (el-kadi et al., 2010) was used to calculate saturation indices of the observed waters with respect to the calcite and dolomite mineral phases and co2 partial pressure (pco2). 4. geochemical charasteristics in table 2 the minimum, maximum and mean values of observed geochemical parameters in thermal waters of ten investigated water sources are given. the mean water temperatures ranged from 19.2 to 54.2 °c. the highest value is observed in varaždinske toplice and the lowest in the water of podevčevo spring (tab. 2). according to the temperature categorization by kovačić & perica (1998), the spring water in podevčevo is subthermal; water from sutinske toplice is homeothermal; waters from harina zlaka, tuheljske toplice, šemničke toplice, topličica (mađarevo) and topličica (gotalovec) are hypothermal and waters from stubičke toplice, krapinske toplice and varaždinske toplice are hyperthermal. the mean ph values ranged from 6.7 to 7.8 (tab. 2). the lowest value is observed in the waters from varaždinske toplice (acid) and the highest is observed in the water of podevčevo spring (alkaline). in stubičke and krapinske toplice lower ph values in waters are also observed. the ph is controlled by dissolution of gases (such as co2, h2s, nh3, ch4) which are entering the aquifer system and geochemical processes such as the synthesis and mineralisation of biomass, redox processes etc. in the aquifer. the higher the amount of dissolved gases in the aquifer system, the lower the ph value will be. from the water quality monitoring of the special hospital for medical rehabilitation varaždinske toplice (special hospital, 2014) a high amount of h2s (10.4 mg/l) in thermal waters has been observed. furthermore, in the waters from stubičke toplice a high content of co2 is observed 101.49 mg/l (hospital stubičke toplice, 2014) and h2s is also detected in the water from krapisnke toplice (hospital krapinske toplice, 2014). also, the contribution of h+ ions during the geochemical processes in the aquifer should not be dismissed. for example during the redox process h+ ions occur, e.g. fes2 + 3.75 o2 + 1.5 h2o= fe(oh)3 + 2so4 2 + 4h+ (pyrite oxidation). geologia croatica 68/1geologia croatica 72 the highest ec value is observed at the varaždinske toplice springs, with a mean value of 1205 ms/cm, while the lowest value is observed at the topličica (gotalovec) spring, with a mean 422 ms/cm (fig. 3). it is visible from fig. 3 that some of the waters have similar ec values, e.g. waters from harina zlaka, tuheljske and stubičke toplice. in the next group there are waters from sutinske, krapinske and šemničke toplice, with topličica (mađarevo) close to them. podevčevo spring waters lie between the last group and the highest ec value. the ec value is influenced by the amount of dissolved solids in the water. if the water contains a high amount of dissolved solids, the ec values will be higher, and vice versa. the amount of dissolved solids in the water is controlled by numerous factors. the type of rock mass which constitutes the catchment area of the spring is one of the important factors. if a rock mass of high solubility (e.g. limestone, volcanic ash) constitutes the catchment area, then the ec will be higher. waters which contain high concentrations figure 3: distribution of mean ec values. figure 4: piper diagram of major constituents in thermal waters. marković et al.: geochemical characteristics of thermal waters of hrvatsko zagorje geologia croatica 73 of co2 and h2s gases, resulting in high concentrations of dissolved co2 and h2s, facilitate the dissolution of carbonate and silicate rocks (yoshimura et al., 2004) and consequently, such waters have higher ec values. moreover, higher water temperature and a more fractured aquifer in combination with low ph values of the water also facilitate dissolution of carbonate rocks and sediments (bertram et al., 1991; gautelier et al., 1999; morse & arvidson, 2002) resulting in high ec values. the thermal water source of varaždinske toplice has the highest concentrations of sodium, potassium, sulphate and chloride (tab. 2). it is followed by the thermal springs of stubičke toplice, the spring in podevčevo and the thermal water source of krapinske toplice (tab. 2). the lowest values are observed in the springs of topličica in gotalovec and mađarevo. higher concentrations of sodium, potassium, sulphate and chloride ions are the consequence of the dissolution of magmatic rocks and siliciclastic (including pyroclastic) sediments in the areas surrounding the thermal water sources. while some 55 ionic species have been reported in ash leachates (witham et al., 2005) the most abundant species usually found are the cations na+, k+, ca2+ and mg2+ figure: 5 a) molar ratios of magnesium and calcium ions in thermal waters; b) bivariate mixing diagram of na+-normalized ca2+ versus na+-normalized mg2+. a) b) geologia croatica 68/1geologia croatica 74 and the anions cl-, fand so4 2(jones & gisalson, 2008; witham et al., 2005). according to the major ionic composition, water from varaždinske toplice belongs to a nacamg-hco3so4 mixed type; podevčevo and stubičke toplice waters belong to a camgna-hco3so4 mixed type; while the rest of thermal waters (harina zlaka, tuheljske toplice, krapinske toplice, topličica (mađarevo), topličica (gotalovec), sutinske toplice and šemničke toplice) belong to the camg-hco3 type (fig. 4). hydrochemical facies, as recognised from water chemistry data, are a consequence of the chemistry of the recharging water, and water–aquifer matrix interactions (e.g. cation exchange), as well as groundwater residence time within the aquifer. two general processes contribute solutes to groundwater: carbonate dissolution and silicate weathering (garrels & mackenzie, 1971). the chemistry of the evolving water depends not only on the bulk chemistry of the matrix, but also on the rate of weathering. meybeck (1987) commented that weathering rates of limestone and dolomite are up to 80 times and 12 times, respectively, faster than silicate weathering rates. from fig. 5a it can be observed that the groundwater chemistry is primarily controlled by the dissolution of carbonate rocks (dolomite and limefigure: 6 saturation index and logpco2 calculations a) in waters of harina zlaka, tuheljske toplice, krapinske toplice, šemničke toplice and topličica mađarevci b) in water of topličica (gotalovec), podevčevo spring, varaždinske toplice, sutinske toplice and stubičke toplice a) b) marković et al.: geochemical characteristics of thermal waters of hrvatsko zagorje geologia croatica 75 stone). in addition, the saturation indices of the observed thermal waters with respect to calcite and dolomite mineral phases indicate the dissolution of carbonate rocks (figs. 6 a, b). generally, it can be stated that the waters of all observed thermal sources were saturated with respect to calcite and dolomite (figs. 6 a, b). it was observed that the saturation index with respect to dolomite was higher than with respect to calcite. the chemistry of waters from varaždinske toplice, podevčevo and stubičke toplice is also influenced by the dissolution of carbonates. however, on the bivariate mixing diagrams (fig. 5b) of na+-normalized ca2+ versus na+-normalized mg2+, the samples from varaždinske toplice, podevčevo and stubičke toplice tend to fall within the silicate weathering domain. this suggests that incongruent leaching of the siliceous volcanic rocks is present in the aquifer. the diagram (fig. 5b) also shows that carbonate dissolution is dominant in waters of the thermal sources of the harina zlaka, krapinske toplice, tuheljske toplice, sutinske toplice, šemničke toplice, topličica (mađarevo) and topličica (gotalovec). also, partial pressure of co2 (pco2) of observed waters were calculated. it was observed that the pco2 values in all sampled waters, were in disequilibrium with respect to the atmosphere (10-3.5 or logpco2= -3.5). the highest partial pressure was observed in the thermal waters of varaždinske toplice and krapinske toplice (figs. 6 a, b) as a consequence of gas influence. the influence of cation exchange was evaluated by an equivalent bivariate plot of corrected bivalent cations versus corrected na+ (fig. 7). concentrations of bivalent cations (ca2+ and mg2+) that may have been involved in exchange reactions were corrected by subtracting equivalent concentrations of associated anions (hco3 and so4 2) that would be derived from other processes (e.g. carbonate or silicate weathering). similarly, na+ that may be derived from the aquifer matrix can be accounted for by assuming that na+ contributions of meteoric origin would be balanced by equivalent concentrations of cl(mclean & jankowski, 2000). for active cation exchange taking place in the aquifer, the slope of this bivariate plot should be -1 (i.e. y = -x) (jankowski et al., 1998). due to small number of samples, all were included in a single diagram. the slope of -1.35 for the observed samples indicates cation exchange (fig. 7). the mixed cation exchange-mineral weathering might be a reflection of the longer residence time of thermal water in the subsurface. although a bivariate plot (fig. 7) shows influence of exchange processes and the bivariate mixing diagram (fig. 5b) indicates silicate weathering, the majority of the analyzed samples tend to fall closer to the carbonate composition than to the silicate composition which means that dolomite is the dominant geothermal aquifer in the study area. 5. conclusion in the region of hrvatsko zagorje there are a lot of spa localities. in this part of croatia geothermal characteristics are favourable. the water temperatures of thermal springs vary from 16 to 65 °c, i.e. from subthermal to hyperthermal. the highest water temperatures are observed in varaždinske and stubičke toplice water sources and the lowest in the podevčevo spring. lower ph values are observed in the waters from varaždinske, stubičke and krapinske toplice and the highest is observed in the water of the podevčevo spring. low ph values are the consequence of h2s and co2 gas dissolution. according to the major ionic composition, the waters belong to types ranging from mixed nacamg-hco3so4 to the camg-hco3 type. the geochemical characteristics of the observed thermal waters indicate that the waters are in equilibrium with dolomite which means that dolomite is the figure 7: bivariate plot of (ca2+ + mg2+) (hco3 + so4 2-) against (na+ cl-). geologia croatica 68/1geologia croatica 76 thermo-mineral and mineral waters – in croatian and french].− institute for geological and geophysical research, belgrade, 69 p. el-kadi a.i., plummer l.n., & aggarwa l.p. (2010): netpath-win: an interactive user version of the mass-balance model, netpath.− ground water, 49/4, 593−599. gajić-čapka, m. & zaninović, k. (2008): klima hrvatske [climate of croatia – in croatian]. – in: zaninović, k. (ed.): klimatski atlas hrvatske 1961. −1990. i 1971.−2000. [climate atlas of croatia 1961−1990 and 1971−2000 – in croatian].− meteorological and hydrological service of croatia, zagreb, 200 p. garrels, r.m. & mackenzie, f.t. (1971): evolution of sedimentary rocks.− norton, new york, 303 p. gautelier, m., oelkers, e.h. & schott, j. (1999): an experimental study of dolomite dissolution rates as a function of ph from 0.5 to 5 and temperature from 25 to 80 oc.− chem. geol., 157, 13–26. haehnlein, s., bayer, p. & blum, p. (2010): international legal status of the use of shallow geothermal energy.− renewable and sustainable energy reviews, 14, 2611–2625. haramustek, b., miholić, s. & trauner, l. (1952): godišnjak baleološko-klimatološkog instituta nr hrvatske [annual report of the balneology and climatology institute of pr croatia – in croatian].− balneology and climatology institute, zagreb, 133 p. hartmann, a. (1925): die mineralund heil-quellen des kantons aargau: ihre geologischen und chemischen verhältnisse [mineral and curative springs of aargau canton: their geological and chemical characteristics – in german].− mitteilungen der aargauischen naturforschenden gesellschaft, 17, 255−320. harvey, k. (2007): healing touch.− sawubona, 75−76. hellman, m.j. & ramsey, m.s. (2004): analysis of hot mineral springs and associated deposits in yellowstone national park using aster and aviris remote sensing.− j. volcanol. geotherm. res., 134/1−2, 195−219. hintz, e. & grünhut, l. (1916): die mineralwässer, moore und mineralschlame [mineral waters, moors and mineral muds – in german].– in: dietrich, e. & kaminer, d. (eds.): handbuch der balneologie, medizinischen klimatologie und balneogeographie.− georg thieme, leipzig, 134−178. hochstein, m.p. (1990): classification and assessment of geothermal resources.– in: dickson, m.h. & fanelli, m. (eds.): small geothermal resources: a guide to development and utilization, unitar, new york, 31−57. horvatinčić, n., srdoč, d., pezdič, j., chafetz, h., sliepčević, a. & krajcar bronić, i. (1991): determination of the origin of geothermal waters in nw yugoslavia by isotopic methods (abstract).− xiv international radiocarbon conference, tucson, az, usa, 20.05.1991.−24.05.1991., radiocarbon, 209 p. horvatinčić, n., srdoč, d., krajcar bronić, i., pezdič, j., kapelj, s. & sliepčević, a. (1996): a study of geothermal waters in northwest croatia and east slovenia. isotopes in water resources management.− vienna, iaea, vol. 2, 470−474. hospital krapinske toplice (2014): http://www.sbkt.hr/termalna.php hospital stubičke toplice (2014): http://www.bolnicastubicketoplice.com iveković, h. & peroš, r. (1981): mineralne i termalne vode hrvatske [mineral and thermal waters in croatia – in croatian].− works of yugoslav academy of sciences and arts, dpt. of math., phys. and techn. sci. and dpt. of med. sci., 190 p. jacobj, c. (1907): einfache warme quellen − akratothermen [regular warm springs akratotherms – in german].– in: keiserliche gesundheitsamt (eds): deutsche bäderbuch. verlag von j. j. weber, leipzig, 24−40. geothermal aquifer in the study area. however, during the movement of thermal water toward the surface, it comes into contact with limestone and volcanic clastic sediments and processes of cation exchange and silicate weathering take placet. the influence of those processes is recognized in the waters of the gotalovec, varaždinske toplice, podevčevo and stubičke toplice thermal water sources. acknowledgement the authors wish to express their gratitude to vlasta juršićmitrović and vinko mraz. this paper represents part of the hydrogeological research conducted within the project “basic hydrogeological map of the republic of croatia” (project no. 181-1811096-3165) funded by the ministry of science, education and sports, republic of croatia. references atkinson, t.c. & davidson, n. (2002): is the water still hot? sustainability and the thermal springs at bath, england.− geol. soc., london, special publications 193, 15−40. axelsson, g. & gunnlaugsson, e. (2000): background: geothermal utilization, management and monitoring.− in: long-term monitoring of highand low-enthalpy fields under exploitation, world geothermal congress short course, kyushu-tohoku, may 28−june 10, 2000, 3−10. bać, j. & herak, m. (1962): prijedlog za određivanje užih i širih zaštitnih zona termomineralnih izvora u hrvatskoj [proposal to determine the immediate and wider protection zone of thermo-mineral resources in croatia – in croatian].– unpubl. report, croatian geological survey, zagreb, 40 p. benderitter, y. & cormy, g. (1990): possible approach to geothermal research and relative costs.– in: dickson, m.h. & fanelli, m. (eds.): small geothermal resources: a guide to development and utilization, unitar, new york, 59−69. bertram, m.a., mackenzie, f.t., bishop, f.c. & bischoff, w.d. (1991): influence of temperature on the stability of magnesian calcite.− am. mineral., 76, 1889–1896. bituh, t., marović, g., petrinec, b., senčar, j. & franulović, i. (2009): natural radioactivity of 226ra and 228ra in thermal and mineral waters in croatia.− radiation protection dosimetry, 133/2, 119−123. borović, s. & marković, i. (2015): utilization and tourism valorisation of geothermal waters in croatia.− renewable and sustainable energy reviews, 44, 52−63. bošnjak, r., čubrić, s., golub, m., grabovski, k. & jelić, k. (1998): geoen – program korištenja geotermalne energije [geoen – programme of geothermal energy utilization – in croatian].− energy institute “hrvoje požar”, zagreb, 124 p. britvić, v. (1988): tehnički izvještaj o bušenju i ispitivanju bušotine sut-3 u sutinskim toplicama [technical report on the drilling and testing of well sut-3 sutinskim toplicama − in croatian].− unpubl. report, geotehnika, zagreb, 32 p. capar, a. (1982): vodoistražni radovi šemničke toplice [water research of šemničke toplice – in croatian].− unpubl. report, geofizika, zagreb, 55 p. deming, d. (2002): introduction to hydrogeology.– mcgraw hill, new york, 468 p. đurović, r. j. (1960): definicija i klasifikacija termalnih, termo-mineralnih i mineralnih voda [definition and classification of thermal, marković et al.: geochemical characteristics of thermal waters of hrvatsko zagorje geologia croatica 77 jankowski, j., acworth, r.i. & shekarforoush, s. (1998): reverse ion exchange in deeply weathered porphyritic dacite fractured aquifer system, yass, newsouth wales, australia.− in: arehart, g.b. & hulston, j.r. (eds.): 9th internat. symp. water– rock interaction. rotterdam: aa balkema, 243–246. jones, m. t. & gisalson, s.r. (2008): rapid releases of metal salts and nutrients following the deposition of volcanic ash into aqueous environments.− geochimica et cosmochimica acta, 72, 3661–3680. jurišić mitrović, v. (2001): izvještaj o rezultatima kemijskih analiza uzoraka voda za zadatak "monografija termalnih i mineralnih voda rh"[report on the results of chemical analysis of water samples for the task "monography of thermal and mineral waters rc" − in croatian].− croatian geological survey, zagreb. kovačić, m. & perica, r. (1998): stupanj korištenja geotermalnih voda u hrvatskoj [the level of thermal water utilization in croatia – in croatian].– hrvatske vode, 25, 355−361. krešić, n. (2010): types and classifications of springs.– in: krešić, n. & stevanović, z. (eds.): groundwater hydrology of springs. butterworth-heinemann, burlington, 31−85. lamoreaux, p.e. & tanner, j.t. (2001): springs and bottled waters of the world. ancient history, source, occurrence, quality and use.− springer verlag, berlin, 250 p. lund, j.w. (1996): balneological use of thermal and mineral waters in the usa, geotherm., 25/1, 103−147. lund, j.w. (2006): geothermal energy focus: tapping the earth's natural heat, refocus, 7/6, 48−51. marković, s. & kovačić, m. (2006): izvorište geotermalne vode u stubičkim toplicama [the source of geothermal water of stubičke toplice – in croatian].− hrvatske vode, 55, 173−181. marović, g., senčar, j., franić, z. & lokobauer, n. (1996): radium-226 in thermal and mineral springs of croatia and associated health risk.− j. environ. radioactivity, 33/3, 309−317. mclean, w. & jankowski, j. (2000): groundwater quality and sustainability in an alluvial aquifer, australia.− in: sililo, a. (ed): xxx iah congress on groundwater: past achievements and future challenges. a.a. balkema, rotterdam. meybeck, m. (1987): global chemical weathering from surficial rocks estimated from river dissolved loads.− am. j. sci., 287, 401–428. miholić, s. (1940a): kemijska analiza termalnih voda u hrvatskom zagorju [chemical analysis of thermal waters of hrvatsko zagorje – in croatian].− rad jugosl. akad. znan. umjet., 267, 195−215. miholić, s. (1952): kemijski sastav i svojstva mineralnih voda [chemical compostion and charachteristics of mineral waters – in croatian].− god. balneo. klimat. insti. nr hrvatske, 1, 7−18. miholić, s. (1959): istraživanje termalnih vrela hrvatskog zagorja [investigation of thermal waters of hrvatsko zagorje – in croatian].− ljetopis jugosl. akad. znan. umjet., 63, 326−328. morse, j.w. & arvidson, r.s. (2002): the dissolution kinetics of major sedimentary carbonate minerals.− earth-science reviews, 58, 51–84. mraz, v. & krsnik, m. (2005): utjecaj temperature podzemne vode na geoelektričnu otpornost u karbonatnim vodonosnicima na primjeru harine zlake – hrvatsko zagorje [effect of temperature on groundwater geophysical resistivity in carbonate aquifers in the example of harina zlake – hrvatsko zagorje – in croatian].− 3. hrvatski geološki kongres, opatija. muffler, p. & cataldi, r. (1978): methods for regional assessment of geothermal resources.− geothermics, 7, 53−89. nicholson, k. (1993): geothermal fluids.− springer verlag, berlin, 264 p. petraccia, l., liberati, g. & masciullo, s.g. (2005): water, mineral waters and health.− clin. nutrit., 25/3, 377−385. polančec, m. (2011): primjena prirodnih hidrogeokemijskih i izotopnih trasera u istraživanju geotermalnih vodonosnih sustava [application of hydrogeochemical and isotopic tracers in the study of geothermal aquifer systems – in croatian].− graduate work, geotechnical faculty in varaždin, university of zagreb, 56 p. roglić, j. (1974): obilježja prirodne osnove [physical geography features].− in: crkvenčić, i. (ed.): geografija hrvatske – knjiga i., školska knjiga, 44–92. routh, h.b., bhowmik, k.r., parish, l.c. & witkowski, j.a. (1996): balneology, mineral water, and spas in historical perspective.− clinics in dermatology, 14/6, 551−554. sanyal, s.k. (2005): classification of geothermal systems – a possible scheme.− proceedings of the 13th workshop on geothermal reservoir engineering, stanford, california, 85−88. schejbal, b. (2003): nova razmatranja o aquae balisse i narodu jaza [new considerations about aquae balissae and the iassi people − in croatian].− opvuscula archeologica, 27, 393−416. special hospital (2014): http://www.minerva.hr šimunić, an. (1986): detaljna geološka istraživanja bliže okolice krapinskih toplica u svrhu lociranja istražne bušotine na termalnu vodu i izvještaj o rezultatima bušenja [detailed geological investigations in the vicinity of krapinske toplice to locate exploration well of thermal water and report on the results of drilling − in croatian].− unpubl. report, croatian geological survey, zagreb, 46 p. šimunić, a. (2008): geotermalne i mineralne vode rh [geothermal and mineral waters of rc – in croatian].− croatian geological survey, zagreb, 343 p. ungemach, p. & economides, m. j. (1987): applied geothermics.− john wiley & sons, chichester, 238 p. witham, c.s., oppenheimer, c. & horwell, c.j. (2005): volcanic ash-leachates: a review and recommendations for sampling methods.– j. volcanol. geoth. res., 141/3–4, 299–326. yoshimura, k., liu, z., cao, j., yuan, d., inokura, y. & noto, m. (2004): deep source co2 in natural waters and its role in extensive tufa deposition in the huanglong ravines, sichuan, china.− chemical geology, 205, 141–153. manuscript received november 14, 2014 revised manuscript accepted january 24, 2015 available online february 27, 2015  in memoriam academician milan herak (1917-2015)  doi: 10.4154/gc.2015.25 obtained his doctorate at the faculty of philosophy with a thesis on triassic limestone sponges from the group sycones. his adviser was fran šuklje. milan herak was employed in 1943 in the geology and palaeontology museum in zagreb, where he worked until 1952. from 1952 to 1958 he was an assistant professor and then associate professor at the technical faculty (now the faculty of mining, geology and petroleum engineering). in 1958 he transferred to the faculty of science at the univer­ sity of zagreb, where until 1961 he was an associate profes­ sor, and from 1961 until his retirement in 1982, professor. from 1959 to 1974 he was head of the geology and palae­ ontology institute. moreover from 1964 to 1966 he was dean of the faculty of science. milan herak is a doyen of croatian geology, as a scien­ tist he was active from 1943 until 2012, when he published his last article in our journal geologia croatica which in a way, was his synthesis on his thoughts on the tectogenetic relationships of dinaric and alpine orogenies. in his long and fruitful life, herak developed a mind-blowing scientific activity, not only regarding the sheer number of publications (over 220, see bibliography), including several books and repeated editions of textbooks, but also, and probably more importantly, regarding the scope and diversity of themes. let us remember only the main areas of his scientific activity. first, he began with palaeontology, which posed no difficulty for him, for he had graduated as a major in biology. how­ ever, he was soon recruited to geology by his teacher, mari­ jan salopek (who quickly recognized his talents and capaci­ ties). herak was the first in this country to apply the biometric method and populational approach in palaeonto­ logy (which of course to­day we know to be the only correct approach). regrettably, in this he was not (until quite re­ cently) always followed by younger authors. his favourite fossil group were calcareous dasyclad algae particularly (but not only) from the triassic. in this he educated a group of younger researchers, so that to­day we can speak with good reason of a zagreb school of calcareous algae. adding to his milan herak, renowned croatian geologist, passed away in zagreb on april 29th, 2015 at the age of 98. he was born on march 5th, 1917, in the small village of brašljevica, in the midst of the žumberak karst area. he grew up and was educated within a large family; therefore he acquired work habits at an early age, as well as a sensibility and appropri­ at an early age, as well as a sensibility and appropri­ ate feeling for team work, dominated by mutual cooperation and support. that proved to be of a substantial advantage later, as in his professional career he often occupied leading positions, acting variously as head of institute, dean, re­ search team leader, chairman of various commissions, boards and committees, but also as teacher, mentor, and ad­ viser. in performing these functions, he knew how to create, stimulate and maintain an inspiring and positive atmosphere. his education included primary school in kast (žumberak), a classical gymnasium in zagreb, and a natural science group at the faculty of philosophy (now faculty of humanities and social sciences) in zagreb from 1937 to 1941 when he graduated. he then spent six months (1942/43) in vienna with julius pia, exploring fossil sponges and fossil calcareous algae. due to health problems he returned earlier than planned to zagreb, and soon afterwards milan herak geologia croatica 68/3 321–330 zagreb 2015 geologia croaticageologia croatica geologia croatica 68/3geologia croatica 322 research on triassic dasyclad algae, herak was invited to join the unesco international project on the triassic, whereupon the stratigraphy and palaeogeography of the tri­ assic became his second main field of activity. here, among other things, most credit goes to him for the world­wide re­ cognition of the muć section as a type-stratum for the tethyan­type (or alpine) lower triassic. herak’s third main area of activity was regional geology and geotectonics. in 1986 (later followed by a series of papers) he presented, already as a mature and experienced researcher, based on his tho­ rough knowledge of the geology of the dinarides, a new conception of the geotectonics of the dinarides, culminating in his last extensive (or synthetic) paper in 2012. as distinct from all previous approaches, herak’s conception was based on a mobilistic approach, which is of course to­day the gene­ rally accepted geological paradigm. last but not least – in contrast and perhaps even of prime importance! is the activi ty in which herak also gained world­wide recognition (per­ haps even the greatest) but for which he also deserved the greatest credit in the croatian economy, is the geology and hydrogeology of karst. here, too, we may speak with good reason of the zagreb karst research school. in contrast to vir­ tually all the previous investigations of karst, that were ba­ sically descriptive and limited to geomorphology – and yet pretending to having developed some all­encompassing and generally valid theories – herak recognized that for success­ ful solution of each particular case first the geological un­ derground (and genesis) should be resolved (or unravelled). for on it depends the distribution and behaviour of both sur­ face and underground water streams, as well as all other karst features (caves, caverns, etc.), including the possibility of storage reservoirs (lakes), the latter being of course of direct economic usefulness. this was of particular significance for the post­second­world­war developing croatian economy, so that to­day we have functioning our largest hydroelectric power plants on accumulation lakes: peruča, senj, vinodol, rječina, obrovac, as well as in the former yugoslavia: on drina (in serbia and bosnia­herzegovina), neretva (in bos­ nia and herzegovina), and tara and morača (in montenegro) rivers, as well as a number of smaller ones. these success­ ful solutions – which were, at first, rather sceptically viewed by the world karstologists community – brought to herak the well­deserved reputation of being the top­level expert for karst hydrogeology. thus he was engaged by the un (unesco and fao) to solve the problem of water supply in egypt, lebanon, greece, turkey and other peri­mediter­ ranean countries, as well as in iran and the caribbean (ja­ maica). as early as 1965 the well­known international pub­ lishing house elsevier invited herak to be the co­editor (with victor stringfield) and main contributor of the first mono­ graph on the karst of the northern hemisphere and after a few years, in 1972 the book karst, important karst regions of the northern hemisphere, was published and enthusiastically greeted by the world karstologic community, being, at that time, the first and only book of such a broadly encompas sing scope. in a national context, the culmination of his research of the dinaric karst was the basic hydrogeological map of the dinaric karst at 1:500,000 (in cooperation with stjepan bahun), published in 1974 and which later served as the base for the hydrogeological map of the former yugoslavia at the same scale. in all his fields of activity, which were also pioneering in croatia, in addition to the geology and hydrogeology of karst in which he acquired the world­wide renowned status, herak left behind well­trained groups of competent younger researchers who, more or less successfully, continue his work. moreover, herak also published papers in the fields of epistemology, the history of geology, bibliographies, and in the very beginning, in museology. herak became a corresponding member of the croatian (then yugoslav) academy of sciences and arts in 1963, and after ten years (arguably waiting too long), in 1973, was elected to full membership. soon he became the vice­presi­ dent of the academy (1975­1978), which was followed by a series of functions: first deputy secretary and then secretary of the department of natural sciences, which demonstrates his positive, always constructive character, and willingness to accept a lower­ranking function. later, he was for many years a member of the presidency, editor­in­chief of several journals (periodicals), head of the committee for karst re­ search, committee for geotectonics, and institute for qua­ ternary palaeontology and geology. his discussions in the academy, as well as in all other occasions, will be remem­ bered for his constructive, well­meaning, conciliatory (but not humouring or submissive) tone. he was the correspond­ ing member of the austrian academy of science from 1977 and of the slovenian academy of sciences and arts from 1991. in 1977 he was also elected as a corresponding mem­ ber of the serbian academy of sciences and arts, but he re­ cinded his membership in 1991. in the croatian geological society he was, from its onset in 1951, its first secretary, later becoming its president. in addition, he was for many years a member of german, austrian, swiss and french geologi­ cal societies. teaching activity of professor herak started back in 1949 as a part­time lecturer at the faculty of science with two new introduced courses palaeobotany and palaeobio­ logy. at the faculty of technics herak introduced the course engineering geology. after transfer to the geology depart­ ment of the faculty of science in 1958. along with the stan­ dard courses herak introduced two new karst geology and regional geology with geotectonics. he was a mentor to a large number of graduates, masters and doctorate students, and thus significantly influenced the development of geo logy in croatia. in 1960 postgraduate studies in geology were founded at the faculty of science and herak was the first leader. in addition to the university of zagreb, herak taught at postgraduate studies level in colleges of the universities of sarajevo and belgrade. as a long time university professor milan herak wrote number of textbooks, some of which are still used. it is worth emphasizing the textbook of geology that has seen as many as 5 editions, which was the basic textbook for numerous generations of geologists at the university of zagreb, as well as on a number of faculties in the former yugoslavia. the gušić and juračić: in memoriam academician milan herak (1917-2015) geologia croatica 323 first edition was in 1960 and fifth in 1990, and in total about 10,000 copies were printed. this textbook actually integrated three textbooks: general (or physical) geology; stratigraphic (historical) geology; and regional geology. after his retire­ ment, he was elected in 2001 to the position of professor emeritus in recognition of his contributions to the develop­ ment of the university of zagreb. milan herak contributed significantly also to the popu­ larization of geology through numerous articles and popular books. among them it is worth mentioning the kora zem­ ljina povijesnica života (earths crust – history of life) book­ let published in 1945 as the fifth book in the series „little scientific library hpd“ and the popular – professional book: earth – evolution, structure, dynamics, sources of raw materials with co­authors vanda kochansky­devide, velimir kranjec and boris šinkovec, which was printed by the aca­ demy in 1976. in 2015, the croatian geological society and the pub­ lishing house izvori printed academician herak’s autobio­ graphy titled my life without signposts, a manuscript which he finished on his 96th birthday. in it he put forward many important and interesting pieces of information which lit up his life, but also the development of geology and overall sci­ ence in croatia in the last seventy years. academician milan herak was also very socially en­ gaged. thus, for example in the establishment of the croatian geological society in 1951, he was elected the first secre­ tary, and later became chairman, and since 1976 he was the society’s honorary member. herak was a recipient of numerous awards and decora­ tions: the city of zagreb memory medal 1965, ruđer bošković award 1968, lifetime achievement award 1976; order of work with golden wreath 1981, order of merit for people with golden star 1986, and order of croatian mor­ ning star with stjepan radić’s image 1998. herak had a rich and meaningful life with extraordinary achievements. his harmonious family were a great support, especially his wife, in the true sense of the word a lifetime companion, mrs. ojdana herak (born allegretti) whom he met while still as a student. for all that professor and academician herak gave to croatian and world’s science, may his memory live on! ivan gušić and mladen juračić bibliography books 1. herak, m. (1945): kora zemljina povijesnica života [earth crust as history of life – in croatian].– hrv. prir. društvo, za­ greb, mala naučna knjižnica, 5, 40 p. 2. herak, m. (1948): la crosta terrestre documentario dell’evoluzione della vita.– instituto edit. della croatia, za­ gabria, 38 p. 3. tajder, m. & herak, m. (1951): petrografija i geologi­ ja [petrography and geology – in croatian].– školska knjiga, zagreb, viii+231 p. 4. herak, m. (1953): paleobotanika za geologe i biologe [pa­ leobotany for geologists and biologists– in croatian].– školska knjiga, zagreb, vii+160 p. 5. tajder, m. & herak, m. (1959): petrografija i geologi­ ja. ii izd. [petrography and geology, ii edition – in croatian].– školska knjiga, zagreb, x+280 p. 6. herak, m. (1960): geologija – struktura, dinamika i his­ torija zemlje [geology – structure, dinamics and history of earth – in croatian].– školska knjiga, zagreb, xi+433 p. 7. herak, m. (1963): paleobotanika. ii izd. [paleobotany, ii edition – in croatian].– školska knjiga, zagreb, xi+180 p. 8. tajder, m. & herak, m. (1966): petrografija i geologi­ ja. iii izd. [petrography and geology, iii edition – in cro a­ tian].– školska knjiga, zagreb, x+400 p. 9. herak, m. & stringfield, v. t., eds. (1972): karst, important karst regions of the northern hemesphere, else­ vier, amsterdam, xv+551 p. 10. tajder, m. & herak, m. (1972): petrologija i geologija. iv izd. [petrography and geology, iv edition – in croatian].– školska knjiga, zagreb, x+356 p. 11. herak, m. (1973): geologija. struktura, dinamika i razvoj zemlje, ii izd. [geology – structure, dinamics and history of earth, ii edition – in croatian].– školska knjiga, zagreb, xii+465 p. 12. herak, m, kochansky-devidé, kranjec, v. & šin kovec, b. (1976): zemlja – evolucija, struktura, di­ namika i izvor sirovina [earth – evolution, structure, dynam­ ics and resources – in croatian].– jugosl. akad. znan. i umjetn., zagreb, 259 p. 13. herak, m. (1984): geologija. iii izd. [geology, iii edition – in croatian].– školska knjiga, zagreb, xv+429 p. 14. herak, m. (1987): geologija. iv izd. [geology, iv edition – in croatian].– školska knjiga, zagreb, xv+433 p. 15. herak, m. (1990): geologija. v izd. [geology, v edition – in croatian].– školska knjiga, zagreb, xv+433 p. 16. herak, m (2002): povijesni temelji hrvatske geologije [historic foundations of croatian geology, iii edition – in croatian].– hrvatska akademija znanosti i umjetnosti, za­ greb, 183 p. 17. herak, m (2006): medvednica – zagonetno zagrebačko gorje [medvednica – puzzling zagreb mountain – in croa­ tian].– posebna izdanja hrvatske akademije znanosti i umjet­ nosti i hrvatskog geološkog instituta, zagreb, 195 p. 18. herak, m. (2015): moj životni put bez putokaza [my life without signposts – in croatian].– hrvatsko geološko društvo and izvori, zagreb, 159 p. scientific papers 1. herak, m. (1943): zur kenntnis tradischer kalk­ schwämme (sycones).– n. jb. min. geol. paläont., (abh.), (b), stuttgart, 88, 107–135. 2. herak, m. (1944): triaske vapnene spužve iz skupine „sycones“ [triadische kalkschwämme aus der gruppe „sycones“].– vjestnik hrv. drž. geol. zavoda i hrv. drž. ge­ ol. muzeja, 2/3, 41–70. 3. herak, m. (1947): prilog stratigrafskom raščlanjivanju mezozojskih naslaga jugozapadnog dijela žumberačke gore.– geol. vjesnik, 1, 3–5. geologia croatica 68/3geologia croatica 324 4. herak, m. (1947): starost i sistematske značajke spiljskog medvjeda hrvatske [geological age and taxonomical char­ acters of cave­bear of croatia – in croatian].– geol. vjesnik, 1, 12–47. 5. herak, m. (1950): ladiničke dasycladaceae jugoslavije i njihovo stratigrafsko značenje.– rad jugosl. akad. znan. i umjetn., 280/3, 115–142. 6. herak, m. (1951): ladinic dasycladaceae of yugoslavia and their stratigraphical significance.– bull. intern. acad. yougoslav. sci. et beaux-arts, zagreb, 3, 51–56. 7. herak, m. (1952): značenje alge sphaerocodium bornemanni rothpletz za interpretaciju gornjeg trijasa u području zagorske mrežnice.– rad jugosl. akad. znan. i umjetn., 289/4, 187–195. 8. herak, m. (1952): die bedeutung der alge sphaeroco­ dium bornemanni rothpletz für die interpretation der ober­ trias im gebiet von zagorska mrežnica.– bull. intern. acad. yougosl. sci. et beaux-arts, zagreb, 7, 85–88. 9. herak, m. (1954): o geološkim prilikama područja ko­ rane uzvodno od slunja [uber die geologischen verhaltnisse des korana gebietes von slunj – in kroatien].– geol. vjes­ nik, 5–7, 7–24. 10. herak, m. (1956): geologija samoborskog gorja [geolo­ gie des samoborer gebirges. acta geol].– jugosl. akad. znan. i umjetn., 1, (prir. istraž. 27), zagreb, 49–73. 11. herak, m. (1956): o nekim hidrogeološkim problemima male kapele [on some hydrogeological problems of the karst mountain mala kapela in lika, croatia].– geol vjes­ nik, zagreb, 8–9, 19–37. 12. herak, m. (1956): o mezozoiku područja korane između barilovića i poloja (über das mesozoikum des korana ge­ bietes zwischen barilović und poloj).– geol. vjesnik, 8–9, 53–66. 13. herak, m. (1956): stratigrafska interpretacija trijaskih sedimenata s dasikladacejama u okolici gračaca u hrvatskoj [stratigraphische interpretation triadischer sedimente mit dasycladaceen der umgebung von gračac in kroatien]. ac­ ta geol., 1, (prir. istraž. 27), jugosl. akad.znan.i umjetn., za­ greb, 149–154. 14. herak, m. & malez, m. (1956): teutloporella herculea (stoppani) in the district of golubovec, n­w croatia.– bull. sci. cons. acad. yougosl., 2/4, 106. 15. herak, m. (1957): osnovni principi rada u našim geološko­ paleontološkim muzejima [basic principles of work in our geological and paleontological museums].– muzeji, zagreb, 11–12, 49–54. 16. herak, m. (1957): znanstveno djelo dragutina gorja no­ vića krambergera.– geol. vjesnik, 10, 1–7. 17. herak, m. (1957): geološka osnova nekih hidroloških po­ java u dinarskom kršu (geologische grundlagen einiger hy­ drologischen erscheinungen im dinarischen karst).– zbor­ nik 2. kongr. geol. jugosl., sarajevo, 523–539. 18. herak, m. (1957): geološka podloga krškog područja.– savezno savj. o kršu, split. krš jugosl., 5, 11–23. 19. herak, m. (1957): novi nalazi sferokodija u hrvatskoj i sloveniji (neue funde von sphaerocodium in kroatien und slowenien).– geol. vjesnik, 10, 31–38. 20. herak, m. (1957): some problems in the dasyclad genus diplopora. micropaleotology, 3/1, 49–52. 21. herak, m. (1958): the dasyclad genus physoporella in the anisian of yugoslavia. j. paleont., soc. india (birbal sahni mem.), lucknow, 3, 59–63. 22. herak, m. (1959): prilog geologiji i hidrogeologiji otoka hvara (zur geologie und hydrogeologie der insel hvar).– geol. vjesnik, 12, 135–148. 23. herak, m. & kochansky-devidé, v. (1959): jurassic calcareous algae in some new localities in the dinaric mountains.– bull. sci. cons. acad. yougosl., (a), 102–104. 24. herak, m. (1960): calcareous algae of the young palae­ zoic and mesozoic of yugoslavia, and their applications in the stratigraphy. rep. 21. sess., norden (intern. geol. con­ gr.), copenhagen, 6, 90–97. 25. herak, m. (1960): geologija gračačkog polja u lici (ge­ ologie des karst polje von gračac in der lika, kroatien). geol. vjesnik, 13, 31–56. 26. herak, m. (1960): kreda s ofiolitima u ivanšćici (sjevero­ zapadna hrvatska) (kreide mit ophiolithen in der ivanšćica, nw kroatien). acta geol., 2, (prir. istraž. 29), jugosl. akad. znan. i umjetn., 111–120. 27. herak, m. & kochansky-devidé, v. (1960): gym­ nocodiacean calcareous algae in the permian of yugoslavia (gimnokodijacejske vapnenačke alge u permu jugoslavije). geol. vjesnik, 13, 185–196. 28. kochansky-devidé, v. & herak, m. (1960): on the carboniferous and permian dasycladaceae of yugoslavia (o karbonskim i permskim dasikladacejama jugoslavije). geol. vjesnik, zagreb (1959), 13, 65–96. 29. herak, m., bojanić, l., šikić, d. & magdalenić, a. (1961): novi elementi tektonike u području gornjeg toka rijeke kupe (neue elemente der tektonik im gebiet des oberlaufs des kupa­flusses). geol. vjesnik, 14, 245–251. 30. herak, m. (1962): tektonska osnova hidrogeoloških odnosa u izvornim područjima kupe i korane (s plitvičkim jezerima) (tektonische grundlage der hydrogeologischen verhaltnisse in der quellengebieten von kupa und korana mit plitwitzer seen). referati 5. sav. geol. fnr jugosl., be­ ograd, 3, 17–25. 31. herak, m. (1962): trias de la yugoslavie. geol. vjesnik, 15/1, 301–310. 32. herak, m. (1963): trias de yugoslavie. in: le trias de la france et des regions limitrophes. mem. bureau rech. geol. min., 15, 477–454. 33. herak, m. & bahun, s. (1963): prilog stratigrafskoj analizi naslaga u području slunj-komesarac-rakovica, hr­ vatska (ein beitrag zur stratigraphischen analyse der ab­ lagerungen im gebiet slunj­komesarac­rakovica, kroat­ ien). geol. vjesnik, 16, 33–34. 34. herak, m. & kochansky-devidé, v. (1963): jung­ palaozoische kalkalgen aus dem bukk­gebirge, nordun­ garn, geol. hung., 28, 57–69. 35. herak, m. (1965): comparative study of some triassic dasycladaceae in yugoslavia (komparativni studij nekih tr­ ijaskih dasikladaceja u jugoslaviji). geol vjesnik, zagreb 18/1, 3–34. 36. herak, m. (1965): geologische űbersicht des dinarischen karstes. naše jame, 7, 5–11. 37. herak, m. (1965): naslage trijasa u okolici sv. roka u lici (triasablagerungen in der umgebung von sv. rok in gušić and juračić: in memoriam academician milan herak (1917-2015) geologia croatica 325 der lika). acta geol., 5, (prir. istraž. 35), jugosl. akad. znan. i umjetn., 85–100. 38. herak, m., majcen, ž. & korolija, b. (1965): prilog paleontološkoj dokumentaciji mezozoika u samoborskom gorju i si žumberku (beitrag zur palaontologischen doku­ mentation des mesozoikum im samoborer gebirge und dem ne žumberak). geol. vjesnik, 18/2, 325–331. 39. herak, m. (1966): die kalkalgen in der stratigraphie der dinariden (jungpalaozoikum und mesozoikum). mitt. geol. ges., wien, 58, 210–217. 40. herak, m. & bojanić, l. (1966): revizija trijasa u području rijeke korane izmedju barilovića i slunja (revision der triasablagerungen im gebiet des flusses korana zwischen barilović und slunj). geol. vjesnik, 19, 47–51. 41. herak, m., bojanić, l., gušić, i. & cukor, v. (1966): paleontološka dokumentacija jure u području rijeke korane izmedju barilovića i slunja (palaontologische dokumenta­ tion der juraablagerungen im gebiet des flusses korana zwischen barilović und slunj). geol. vjesnik, 19, 53–55. 42. herak, m. (1967): anisische dasycladaceen vom gosau­ kamm (dachsteingebiet, oesterreich). mitt. geol. ges., 59/2, 213–217. 43. herak, m. (1967): mesozoische kalkalgen der insel chi­ os (griechenland) n. jb. geol. palaeont. (abh.), 129/1, 97– 104. 44. herak, m. (1967): noviji rezultati istraživanja osnovnih stratigrafskih jedinica u žumberku (neue ergebnisse der un­ tersuchungen von stratigraphischen haupteinheiten in žumberak, w kroatien). geol. vjesnik, 21, 111–116. 45. herak, m., sokač, b. & šćavničar, b. (1967): cor­ relation of the triassic in sw lika, paklenica and gorski kotar, croatia. geol. sbornik slov. akad. vied (geol. car­ pathica), 18/2, 189–202. 46. herak, m. & škalec, d. (1967): kalkalgen im perm des samoborer gebirges (vapnenačke alge u permu samo­ borskog gorja). geol. vjesnik, zagreb (1966), 20, 37–39. 47. herak, m., mikulec, s. & žugaj, m. (1968): present and prospective water power development in the karst of yugo slavia. world power conf. moscow, sec. c2, paper 158, 1–29. 48. herak, m. (1969): current geologic problems of the di­ narides. 3. simp. dinarske asoc., zagreb, 1, 1–9. 49. herak, m., bahun, s. & magdalenić, a. (1969): pozitivni i negativni utjecaji na razvoj krša u hrvatskoj (pos­ itive and negative influences on the development of the karst in croatia). krš, jugosl., akad. znan. i umjetn., 6, 45–78. 50. herak, m., mikulec, s., stojić, p. & tričković, t. (1970): problems relative to the construction of dams and reservoirs in karst areas. 10. congr. grands barrages comm. intern. grands barrages., montreal, 10, 899–908. 51. herak, m., polšak, a., gušić, i. & babić, lj. (1970): dynamische und räumliche sedimentationsbedingungen der mesozoischen karbonatgesteine im dinarischen karstgebiet. verh. geol. bundesanst., wien, 4, 637–643. 52. herak, m. (1971): tektonska osnova hidrogeoloških po­ java u okolici skrada, gorski kotar. ljetopis jugosl. akad. znan. i umjetn., 75, 425–426. 53. herak, m. (1971): beitrag zur rekonstruktion der oro­ genetischen dynamik in der dinariden kroatiens. i simp. o orog. fazama u prostoru evrope, beograd­bor (1970), be­ ograd, 35–40. 54. herak, m. (1971): razvoj hidrogeoloških koncepcija u dinarskom kršu (development of the geological theories on the dinaric karst). zbornik radova rud.­geol. fak., beograd, 13, 227–239. 55. herak, m. (1971): neke specifičnosti dinarskog krša (some specific features of the dinaric karst). simp. o zaštiti prirode u našem kršu (zagreb, 1970), jugosl. akad. znan. i umjetn., zagreb, 25–34. 56. herak, m. (1972): karst of yugoslavia. in: karst, impor­ tant karst regions of the northern hemisphere, m. herak & v. t. stringfield, eds., elsevier, amsterdam, 25–83. 57. herak, m. & stringfield, v. t. (1972): historical re­ view of hydrogeologic concepts. in: karst, important karst regions of the northern hemisphere, m. herak & v. t. stringfield, eds., elsevier, amsterdam, 19–24. 58. herak, m. & stringfield, v. t. (1972): conclusions. in: karst, important karst regions of the northern hemi­ sphere, m. herak & v.t. stringfield, eds., elsevier, amster­ dam, 507–512. 59. herak, m. (1973): novija istraživanja trijasa u hrvatskoj (neuere untersuchungen der trias kroatiens). geologija, ljubljana,16, 375–378. 60. herak, m. (1973): some tectonical problems of evapor­ itic area in the dinarides of croatia (neki tektonski problemi pojasa s evaporitima u dinaridima hrvatske). geol. vjesnik, zagreb (1972), 26, 29–40. 61. herak, m.,mikulec, s., stojić, p. & tričković, t. (1973): jugoslavenski nacionalni komitet za visoke brane. sintetički izvještaj br. 10. saopštenja 9. kongr. jugosl. kom. za visoke brane, zlatibor, 335–339. 62. herak, m. (1974): palaogeographie und fazies­entwick­ lung wahrend der trias in den dinariden kroatiens. (symp. wien, 1973.: die stratigraphie der alpin­mediterr. trias). oesterr. akad. wiss. schriftenreihe der erdwis. komm., wien, 2, 101–106. 63. herak, m. (1974): principi stratigrafske klasifikacije i ter­ minologije (principles of stratigraphic classification and ter­ minology). nafta, zagreb, 25/5, 233–236. 64. herak, m. & bahun, s., (eds.), (1974): osnova hidro­ geološke karte dinarskog krša, 1 : 500 000, geol.­ paleont. zavod prir.­matem. fakulteta, zagreb. 65. herak, m. (1975): geotectonics and karst (geotektonika i krš). acta geol., 8/21, (prir. istraž. 41), jugosl. akad. znan. i umjetn., zagreb, 387–395. 66. herak, m. (1975): some comments on stratigraphic clas­ sification and terminology (neke primjedbe uz stratigrafsku interpretaciju i terminologiju). geol. vjesnik, zagreb, 28, 55– 63. 67. herak, m. (1976): geološki pristup tipizaciji terena za konsolidaciju. 1. jugosl. simp. za konsol. tla. zbornik refer­ ata, zagreb, 31–32. 68. herak, m. (1976): hidrogeološki aspekt dinarskog krša. simp.: ekološko valoriziranje primorskog krša. jugosl. akad. znan. i umjetn., split, 59–62. 69. herak, m. (1976): jugoslavenski prilog poznavanju hid­ rogeologije i geomorfologije krša. hidrogeologija i vodno geologia croatica 68/3geologia croatica 326 bogatstvo krša. zbornik jugosl.­amer. simp., dubrovnik (1975), sarajevo, 1–24. 70. herak, m. (1976): the yugoslav contribution to the knowledge of karst hydrogeology and geomorphology. karst hy­ drology and water resources. proceed. u.s.– yugosl. symp., dubrovnik (1975), water res. publ., fort collins, 1, 3–30. 71. herak, m., marinčić, s. & polšak, a. (1976): ge­ ologija otoka hvara (geology of the island of hvar). acta geol., 9/1, (prir. istraž. 42), jugosl. akad. znan. i umjetn., za­ greb, 1–14. 72. herak, m. (1977): tecto-genetic approach to the classifi­ cation of karst terrains (tektogenetski pristup klasifikaciji krških terena). krš jugoslavije jugosl. akad. znan. i umjetn., zagreb, 9/4, 227–238. 73. herak, m., kochansky-devidé, v. & gušić, i. (1977): the development of the dasyclad algae through the ages. in: fossil algae, e. flugel, edt.: springer verlag, ber­ lin, 143–153. 74. trumić, a., mikulec, s. & herak, m. (1977): water resources of the dinaric karst as a factor of regional devel­ opment in yugoslavia. united nations water conference, e/ conf., mar del plata, 70/tp 54, 1–15. 75. herak, m. (1979): surface and subsurface morphology in the molai area, peloponnesus. water resources develop­ ment in the molai area, laconia, greece. fao, undp­ ago:dp/gre/, 77/023, working document, 1, iv+17 p. 76. herak, m. (1979): on the origin of the nappe­units in the area gorski kotar – ljubljansko barje). vesnik zav. geol. geofiz. istraž. (a), beograd, 37, 59–64. 77. pantić, n., herak, m., drovenik, m. & vidović, m. (1979): kadrovi i naučnoistraživački rad u geologiji sfrj. 9. kongres geol. jugosl., sarajevo, 1978., zbornik ra­ dova, sarajevo, 2, 37–44. 78. herak, m. (1980): o preduvjetima selekcije i specijaliza­ cije znanstvenih radnika u geoznanostima. zbornik simp. znan. podmladak u samoupravnom društvu, zagreb (1979), 37–40. 79. herak, m. (1980): sustav navlaka između vrbovskog i del nica u gorskom kotaru – hrvatska (the nappe­system between vrbovsko and delnice in gorski kotar – croatia). acta geol., 10/2, (prir. istraž. 44), jugosl. akad. znan. i umjetn., zagreb, 35–51. 80. herak, m.(1980): zur ergänzung tektonischer grundlagen der westkroatischen aussendinariden. ann. naturhistor. mus., wien, 83, 127–133. 81. herak, m. & bahun, s. (1980): the role of the calcare­ ous breccias (jelar formation) in the tectonic interpretation of the high karst zone of the dinarides. geol. vjesnik, za­ greb (1979), 31, 49–59. 82. herak, m. jašarević, i., banjad, i. šikić, v., vrk­ ljan, m., dušek, a., viljevac, ž, kovačević, s. & sviben, d. (1980): geološka i geotehnička istraživanja s projeknim rješenjem tunela kroz gorski kotar, 5. simp. ju­ gosl. društva za mehaniku stijena i podzemne radove, split, 1, iv–1, 193–211. 83. herak, m., magdalenić, a. & bahun, s. (1981): karst hydrogeology. pollution and water resources, colum­ bia univ. seminar series. g. j. halasi-kun, edt., new york, 14/1, 163–178. 84. herak, m. (1982): regionalnogeološka osnova cvijićeve koncepcije krša (regional-geologic basis of cvijić concept of karst). naučno delo jovana cvijića. naučni skupovi srp. akad. nauka i umetn., beograd, 11/2, 81–86. 85. herak, m. & polšak, a. (1982): geologija u hrvatskoj 1977–1981. geol. vjesnik, zagreb, 35, 229–234. 86. herak, m. (1983): some ideas and dilemmas concerning the genesis and tectonics of the adriatic and peri­adriatic areas. guide book 4th i. a. s. regional meeting (split, 1983), lj. babić & v. jelaska, eds., zagreb, 7–11. 87. herak, m., šćavničar, b., šušnjara, a., đur đanović, ž., krystyn, l. & gruber, b. (1983): the lower triassic of muć, proposal for a standard section of the european upper scythian. oesterr. akad. der wiss., schrif­ tenreihe der erdwiss. kommissionen, wien, 5, 93–106. 88. herak, m. (1984): effects of karst types on stream flow regimes. guide to the hydrology of carbonate rocks, ph. e. lamoreaux, b. morere wilson & b. a. memon, eds., stud­ ies and reports in hydrology 41, unesco, paris, 152–156. 89. herak, m. (1984): geotektonski okvir speleogeneze (ge­ otectonical frame of speleogenesis). zbornik devetog spe­ leol. kongresa jugoslavije (karlovac, 1984), zagreb, 111– 129. 90. herak, m. (1984): osvrt na glavne tektogenetske stadije dinarida (review of the main tectogenetic stages of the di­ narides). radovi akad. nauka i umjetn. bosne i hercegovine, 75, odjeljenje tehn. nauka, sarajevo, 8, 81–88. 91. herak, m. & burdon, d. j. (1984): outlets. guide to the hydrology of carbonate rocks, ph. e. lamoreaux, b. morere wilson & b. a. memon, eds., studies and reports in hydrology, 41, unesco, paris, 138–141. 92. herak, m. (1985): o odnosu jadranskih i dinarskih struk­ tura (on the relation of the adriatic and dinaric structures). rasprave slov. akad. znan. in umetn. (iv razr.), ljubljana, 26, 401–414. 93. herak, m. (1985): geološka karta fužina i okolice (geol­ ogy of the environs of fužine). u povodu 200. god. škole fužine (1785–1985), 214–220 + 465. 94. herak, m. (1986): a new concept of geotectonics of the dinarides (nova koncepcija geotektonike dinarida). acta geol., 16/1, (prir. istraž. 53), jugosl. akad. znan. i umjetn., zagreb, 1–42 95. herak, m. (1986): geotektonski okvir zaravni u kršu (ge­ otectonic frame of karst plains). simp. o kraškom površju, inšt. za raziskovanje krasa, slov. akad. znan. in umetn. (pos­ tojna, 1985), acta carsologica, ljubljana (1985–1986), 14/15, 13–18. 96. herak, m. (1987): relationship between adriatic and di­ naric platforms. intern. symp. on the evolution of the karstic cabornate platform. inst. di geol. e paleont. univ. of trieste (abstracts), 37. 97. herak, m. (1987): the correlation between the relief of the mohorovičić discontinuity and the tectonic pattern of the dinarides (korelacija između reljefa mohorovičićeva dis­ kontinuiteta i tektonske građe dinarida). acta geol., 17/1–2, (prir. istraž. 55), jugosl. akad. znan. i umjetn., zagreb, 5–11. 98. herak, m. (1987): trijas dinarida na prijelazu između her­ cinske i alpinske orogeneze (the triassic of the dinarides, the linking period of hercynian and alpine orogenesis). gušić and juračić: in memoriam academician milan herak (1917-2015) geologia croatica 327 zbornik radova posvećen akademiku z. bešiću, crnogorska akad. nauka i umjetn., titograd, 33–38. 99. herak, m. & bukovac, j. (1988): tektonsko okno du­ ralije u žumberku (tectonic window of duralije in žum berak). geol. vjesnik, zagreb, 41, 231–236. 100. herak, m. (1989): relationship between adriatic and di­ naric carbonate platforms. mem. soc. geol. it., roma (1987), 289–293. 101. herak, m. (1990): geotectonics, karst morphology, and environmental problems. environ. geol. water sci., new york, 14/3, 59–60. 102. herak, m., jamičić, d., šimunić, a. & bukovac, j. (1990): the northern boundary of the dinarides (sjeverna granica dinarida). acta geol., 20/1, (prir. istraž. 60), jugosl. akad. znan. i umjetn., zagreb, 5–27. 103. herak, m. (1991): dinaridi – mobilistički osvrt na genezu i strukturu (dinarides – mobilistic view of the genesis and structure). acta geol., 21/2, (prirodosl. istraž. 63), hrv. akad. znan. i umjetn., zagreb, 35–117. 104. herak, m. (1991): pre­neogene tectonic pattern of the mar gin of the pannonian depression. serb. acad. of sci and arts, acad. conferences, 62 (dept. of nat. and mathem. sci., 4), beograd, 9–14. 105. herak, m. (1993): additional considerations on the epi­ adriaticum, outer dinarides. geol. croat., zagreb, 46/1, 165–168. 106. herak, m. (1994): geotektonika i geotehnika (geotec­ tonics and geotechnics). saopćenja 1 znanstveno-stručnog sa vje tovanja geotehnika prometnih građevina, novigrad (1994), zagreb, 27–36. 107. herak, m. & tomić, v. (1995): continental subduction tectonics in the high karst dinarides of western croatia. geol. croat., zagreb, 48/2, 161–166. 108. herak, m. & juračić, m. (1996): geological basis of environment protection in croatia. pollution and water re­ sources, columbia univ. seminar series, g. j. halasi­kun, ed., centre for reg. studies, pecs, hung. acad. sci. 28 (1994), 233–259. 109. herak, m (1999): tectonic interrelation of the dinarides and the southern alps.– geol. croat., zagreb, 52/1, 83–98. 110. herak m. (2012): a generalized „southern“ review of the tectogenetic relationships oft he „dinarides“ and „alpides“.– geol. croat., zagreb, 65/suppl. 1, 3–35. professional and other papers 1. herak, m. (1944): što je paleobiologija? [what is paleo­ biology? – in croatian].– priroda, zagreb, 34/7–10, 112–116. 2. herak, m. (1944): iz povijesti zemlje i života [from the history of earth and life – in croatian].– znanje i radost. hrv. izd. bibliogr. zavod, zagreb, 3, 160–170. 3. herak, m. (1944): otkriće krapinskog pračovjeka. [dis­ covery of the krapina neanderthal – in croatian].– znanje i radost. hrv. izd. bibliogr. zavod, zagreb, 3, 174–177. 4. herak, m. (1947): zemljina kora i život na njoj izvrgnuti su neprestanim promjenama [earth’s crust and life on it are in constant change – in croatian].– zadružni kalendar, za­ greb, 17, 257–262. 5. herak, m. (1954): izvještaj o geološkim istraživanjima u samoborskoj okolini u godini 1952. ljetopis jugosl. akad. znan. i umjetn., zagreb (1951–1952), 59, 84–86. 6. herak, m.(1954): izvještaj o geološkom istraživanju samoborske gore u godini 1951.– ljetopis jugosl. akad. znan. i umjetn., zagreb (1951–1952), 59, 81–83. 7. herak, m. (1955): geologija i mineralogija u srednjoj ško­ li [geology and mineralogy in secondary school – in croa­ tian].– školske novine, zagreb, 6/9, 2. 8. herak, m. (1955): geološka istraživanja u području samo borske gore [geological investigations int he area of sa­ mo borska gora– in croatian].– ljetopis jugosl. akad. znan. i umjetn., zagreb (1953), 60, 279–280. 9. herak, m. (1959): geologija [geology– in croatian].– šumarska enciklopedija, leksikogr. zavod fnrj, zagreb, 1, 437–440. 10. herak, m. (1960): hrvatska – geološki i petrografski sas­ tav tla [geologic and petrographic composition of soil – in croatian].– enciklopedija jugoslavije, zagreb, 124–129. 11. herak, m. (1962): dr josip poljak – in memoriam [dr jo­ sip poljak – obituary – in croatian].– priroda, hrv. prir. dru­ štvo, zagreb, 49/8, 256. 12. herak, m. (1962): news reports. yugoslavia.– micropal­ eontology, new york, 8/2, 287–288. 13. herak, m. (1962): problem geoloških kadrova [the prob­ lem of geological staff – in croatian].– referati 5. sav. geol. fnr jugosl., beograd, 1–12. 14. herak, m. (1962): razvoj geološke nauke u razdoblju od 1951–1961 [the development of geological science in the period 1951–1961 – in croatian].– geol. vjesnik, zagreb (1961), 15, 11–18. 15. herak, m. (1962): vjetar kao geološki faktor [wind as a geological factor – in croatian].– priroda, zagreb, 49/8, 230–234. 16. herak, m. (1963): krš [karst – in croatian].– šumarska enciklopedija, jugosl. leksikogr. zavod, zagreb, 2, 17–20. 17. herak, m. (1963): news reports. yugoslavia. micropale­ ontology, new york, 9/3, 358–359. 18. herak, m. (1965): akademik marijan salopek [academi­ cian marijan salopek – in croatian].– acta geol., 5, (prir. istraž. 35), jugosl. akad. znan. i umjetn., zagreb, 7–11. 19. herak, m. (1965): geološka povijest dinarskog krša [ge­ ologic history of dinaric karst – in croatian].– priroda, za­ greb, 52/5–6, 129–134. 20. herak, m. (1965): news reports. yugoslavia. micropale­ ontology, new york, 11/3, 380. 21. herak, m. (1965): paleontologija hrvatske [croatian paleontology – in croatian].– enciklop. jugosl., zagreb, 6, 417. 22. herak, m. (1966): geološko istraživanje žumberka [geo­ logic investigation of žumberak – in croatian].– ljetopis ju­ gosl. akad. znan. i umjetn., zagreb (1964), 71, 263–265. 23. herak, m. (1968): news reports. yugoslavia. micropale­ ontology, new york, 14/2, 262–263. 24. herak, m. (1968): stanje i problemi razvoja naučnih istraživanja u paleontologiji, stratigrafiji, inženjerskog geolog­ iji i hidrogeologiji [condition and problems of development of scientific research in paleontology, stratigraphy, engineer­ geologia croatica 68/3geologia croatica 328 ing geology and hydrogeology – in croatian].– sav. savj. koord. naučn. del. (studije i prikazi sp. 9), tehničke nauke ser. c/3, beograd, 23–24. 25. herak, m. (1968): s kompasom i čekićem po svijetu, i. dio [with a compass and a hammer in the world, part i – in croatian].– žumberačke novine, zagreb, 3/10, 10. 26. herak, m. (1968): s kompasom i čekićem po svijetu, ii. dio [with a compass and a hammer in the world, part ii – in croatian].– žumberačke novine, zagreb, 3/12, 7. 27. herak, m. (1969): process report for the international hy­ drological working group on the hydrology of the carbonate rocks of the mediterranean basin., fao, rome, 1–32. 28. herak, m. (1969): sveučilište i društvena praksa [univer­ sity and social practice – in croatian].– spomenica sveučilišta, zagreb, 1, 541–548. 29. herak, m. (1969): znanstvena istraživanja u reformiranom sveučilištu [scientific research in the reformed univer­ sity – in croatian].– simp. inst. za društv. istraž. sveuč., za­ greb, 1, 1–6. 30. herak, m. (1969): s kompasom i čekićem po svijetu, iii. dio [with a compass and a hammer in the world, part iii – in croatian].– žumberačke novine, zagreb, 4/13, 9. 31. herak, m. (1969): s kompasom i čekićem po svijetu, iv. dio [with a compass and a hammer in the world, part iv – in croatian].– žumberačke novine, 4/15, 6. 32. herak, m. (1969): s kompasom i čekićem po svijetu, v. dio [with a compass and a hammer in the world, part v – in croatian].– žumberačke novine, zagreb, 4/16, 9. 33. herak, m., mikulec, s. & žugaj, m. (1969): mo gućno sti intenzivnijeg korišćenja vodnih snaga krša. 1. kongr. o vodama jugosl., zagreb, 1, 421–425. 34. grupa autora (1969): geologija i hidrogeologija sliva rijeke save. jugoslavija, regulacija i uređenje save, zagreb, 65 p. 35. herak, m. (1970): dokumenti geološke prošlosti [docu­ ments of geological history – in croatian].– encyclopedia moderna, jugosl. akad. znan. i umjetn., zagreb, 13, 67–70. 36. herak, m. (1970): s kompasom i čekićem po svijetu, vi. dio [with a compass and a hammer in the world, part vi – in croatian].– žumberačke novine, zagreb, 5//18, 6. 37. herak, m. (1970): naše rodno tlo [our native soil – in croatian].– encyclopedia moderna, jugosl. akad. znan. i umjetn., zagreb, 13, 66. 38. herak, m. (1971): reforma organizacije postdiplomskog studija i znanstvenih istraživanja [reform of the organization of postgraduate studies and scientific research – in croa­ tian].– in: za reformu hrv. sveuč. savez stud. hrvatske, za­ greb, 19–21. 39. herak, m. (1971): tragom pradavne prošlosti žumberačkog tla [following the ancient past žumberak soil– in croatian].– in: žumberak u riječi i slici. kult.-prosvj. društvo „žum berak“, zagreb, 10–15. 40. herak, m. (1971): znanstveni rad i poslijediplomski stud­ ij tla [scientific work and postgraduate studies – in croa­ tian].– in: za reformu hrv. sceučilišta, savez stud. hrvatske, zagreb, 22–30. 41. herak, m. (1972): regional geologic approach to the in­ vestigation of groundwaters in karst areas.– 24. intern. geol. congr., montreal (abstracts), 342. 42. grupa autora (1972): glossary and multilingual equiv­ alents of karst terms.– unesco­fao, paris, ii+72. 43. herak, m. (1973): pregled geološke građe like [review of geological structure of lika – in croatian].– zbornik his­ tor. arhiva, 5, (lika u prošlosti i sadašnjosti), karlovac, 79– 85. 44. herak, m. (1973): susreti u kršu. osvrt na dosadašnji rad i perspektive posebna izd. srp. akad. nauka i umetn. spo me­ nica m. t. lukoviću, 60, beograd, 23–25. 45. herak, m. (1973): milan luković (1889–1972) [milan lu ković (1889–1972) – in croatian].– ljetopis jugosl. akad. znan. i umjetn., zagreb, 77, 239–240. 46. herak, m. (1973): geologija. struktura, dinamika i razvoj zemlje, ii izd. [geology – structure, dinamics and history of earth, ii edition – in croatian,].– školska knjiga, zagreb, xii+465 p. 47. grupa autora (1973): karst hydrology in eight circum­ mediterranean countries. a review of the situation in 1969– 1971 made by the working group on the hydrology of car­ bonate rocks of the mediterranean basin. first preliminary edition., unesco­fao, rome, v+21 p. 48. herak, m., magaš, b. & sarić, a. (1973): hidro geološka, geomorfološka i hidrotehnička bibliografija krša jugoslavije (1689–1972), vodopr. problemi krša. bilten po slov ne zajednice izuč. vodopr. probl. krša, sarajevo, 4, 209 p. 49. herak, m. (1974): osvrt na dosadašnji rad i perspektive [overview of the former work and perspectives – in croa­ tian].– spomenica prir.­matem. fak., zagreb, 176–177. 50. herak, m. (1975): (opening speech). 2. znanstv. skup sek­ cije za primjenu geol., geofiz., geokem. znanstv. savjeta za naftu jugosl. akad. znan. i umjetn., zagreb, 13–15. 51. herak, m. (1975): c. a. burk & c. l. drake, eds.: the geology of continental margins (review). springer verlag, berlin-heidelberg-new york, 1974. geol. vjesnik, zagreb, 28, 464–472. 52. (b. k. interview m. heraka) (1975): do odgovora nisam došao. nin, broj 1281, beograd, 12–13. 53. grupa autora (1975): krška hidrologija u osam zemal­ ja na obodu sredozemlja (preveo m. herak). poslovna za­ jednica za izučavanje vodoprivr. problema krša. izdanja, sarajevo, 14, 43 p. 54. herak, m. (1976): kako jednoznačno interpretirati fosile u evoluciji i stratigrafiji? proslava 25. oblj. djelatn. hrv. geol. društva (sažeci referata), zagreb, 3. 55. herak, m. (1976): o geološkoj prošlosti ozaljskog kraja. kaj, zagreb, 9–11, 172–174. 56. herak, m. (1976): cilj, namjena i sadržaj geološke karte sfrj 1:50 000. geol. vjesnik, zagreb, 29, 363–374. 57. herak, m. (1976): u potrazi za silama zemljine evolucije. priroda, 65/3, zagreb, 65–68. 58. herak, m., magaš, b., sarić, a. & habe, f. (1976): prilog bibliografiji krša jugoslavije 1666–1974. (contribu­ tion to the bibliography of karst of yugoslavia 1966–1974).– krš jugoslavije jugosl. akad. znan. i umjetn., zagreb, 9/3, 81–149. 59. pleničar, m., premru, u. & herak, m. (1976): os­ novna geološka karta jugoslavije, list novo mesto 1:100 000, gušić and juračić: in memoriam academician milan herak (1917-2015) geologia croatica 329 l 33–79. geološki zavod, ljubljana (1963–1969). savezni geološki zavod, beograd. 60. herak, m. (1977): tecto-genetic approach to the classifi­ cation of karst terrains. papers 3rd intern. symp. undergr. water tracing (1976), ljubljana (abstracts), 321. 61. herak, m., polšak, a. & prelogović, e. (1978): razvoj geologije u sr hrvatskoj od 1951–1976. god.– geol. vjesnik, 30/2, 611–620. 62. herak, m. (1979): eduard roch (1901–1975).– ljetopis jugosl. akad. znan. i umjetn., zagreb (1975), 79, 699. 63. herak, m. (1981): inženjerskogeološka djelatnost akademika luke marića. spomenica preminulim akademicima, jugosl. akad znan. i umjetn., zagreb, l0, 34–36. 64. herak, m. (1981): uz 45­obljetnicu znanstvenog i nastav­ nog rada vande kochansky­devidé. geol. vjesnik, zagreb, 34, 151­153. 65. herak, m. (1982): ercegovac, m.: mikropaleontologija­ mikropaleobotanika. naučna knjiga, 323 p., 1981. (recenz­ ija).– geol. vjesnik, zagreb, 35, 286–287. 66. herak, m. (1984): o nekim nedorečenostima u rasprava­ ma o znanosti i nas. predavanja jugosl. akad. znan. i umjetn., zagreb, 52, 38 p. 67. herak, m. (1985): geologija u kulturnom i privrednom razvitku hrvatske. scientia yugoslavica, zagreb, 11 (1–2), 57–63. 68. herak, m. (1986): (uvodna riječ). vale vouk 1886–1986, spomenica preminulim akademicima, jugosl. akad. znan. i umjetn., zagreb, 35, 9. 69. herak, m. (1986): mohorovičićev diskontinuitet u geo znanostima. priroda 75, hrvat. prir. društvo, zagreb, 106–107. 70. herak, m. (1986): geologija u zatvorenom krugu, vjes­ nik, zagreb, od 11. 01. 1986. panorama subotom, 8. 71. herak, m., pantić, n., atanacković, m., kara­ mata, s., cvetković, s., bošković, d., buser, s., ivković, b., pruhti, v., kalezić, m. & petrovski, k. (1986): kadrovi i naučnoistraživački rad u geologi­ ji sfrj. 11. kongr. geologa jugosl., tara, 1, 125–158. 72. herak, m. (1987): (uvodna riječ), dragutin gorjanović kramberger 1856–1936. spomenica preminulim akademici­ ma jugosl. akad. znan. i umjetn., zagreb,42, 9–11. 73. herak, m. (1988): geografija i jugoslavenska akademija. geogr. glasnik, zagreb, 50, 129. 74. herak, m. (1988): struktura i dinamika zemlje. atlas sv­ ijeta.– jugosl. leksikogr. zavod, zagreb, 12–18. 75. herak, m. (1988): o našem geotektonskom naslijeđu (on our geotectonic heritage). naučne komunikacije akad. nau­ ka i umjetn. bosne i hercegovine (odjeljenje tehn. nauka), sarajevo, 16, 5–15. 76. herak, m. (1988): in memoriam: akademik josip roglić (1906–1987).– geografski glasnik, zagreb, 50, 129. 77. herak, m. (1988): (pozdrav). zbornik skupa ornitologija u hrvatskoj. jugosl. akad. znan. i umjetn., razred za prir. znan., zagreb, 1. 78. herak, m. (1989): sjećanje na dan oproštaja od akademi­ ka josipa roglića. spomenica preminulim akademicima ju­ gosl. akad. znan. i umjetn., zagreb, 51, 9–11. 79. herak, m. (1989): uloga instituta za geološka istraživanja u razvoju i primjeni geoloških znanosti. geol. vjesnik, 42, xix–xxi. 80. herak, m. (1990): geologija. v izd., školska knjiga, za­ greb, xv+433 p. 81. herak, m. (1990): jugoslavija – geološki i petrografski sas­ tav. enciklop. jugoslavije, jugosl. leksikogr. zavod, zagreb, 6, 167–171. 82. herak, m. (1991): vanda kochansky­devidé (1915–1990). ljetopis jugosl. akad. znan. i umjetn., zagreb, 94, 598–600. 83. herak, m. (1991): mirko malez (1924–1990). ljetopis ju­ gosl. akad. znan. i umjetn., zagreb, 94, 601–602. 84. herak, m. (1991): u spomen vandi kochansky – devidé. spomenica preminulim akademicima jugosl. akad. znan. i umjetn., zagreb, 60, 10–12. 85. herak, m. (1991): brusina i jugoslavenska akademija. zbor nik znan. skupa, zadar (1989), 9–10. 86. herak, m. (1991): govor na predstavljanju knjige j. ba­ labanića „brusina prirodoslovac”.– zbornik znan. skupa, za­ dar (1989), 217–218. 87. herak, m. (1992): sjećanje na akademika mirka maleza. spomenica preminulim akademicima hrv. akad. znan. i umjetn., zagreb, 66, 9–11. 88. herak, m. (1993): geotektonika i geomorfologija. geogr. horizonti, zagreb, 39, 2, 5–9. 89. herak, m. (1993): gjuro pilar (1846–1893), uz stotu ob­ ljetnicu smrti.– vjesnik hrv. akad. znan. i umjetn., zagreb, 1–3, 223–226. 90. herak, m. (1994): pozdravni govor. zbornik znanstvenog skupa gjuro pilar 1846–1893, pos. izd. hrv. akad. znan. i umjetn., zagreb, 3. 91. herak, m. (1994): pilarovo poimanje geodinamike [pilars’ conception of geodynamics – in croatian].– zbornik znanstve­ nog skupa gjuro pilar 1846–1893, pos. izd. hrv. akad. znan. i umjetn., zagreb, 73–84. 92. sakač, k. & herak, m. (1994): znanstveni rad i životni put gjure pilara (scientific work and life itinerary of gjuro pilar). zbornik znanstvenog skupa gjuro pilar 1846–1893, pos. izd. hrv. akad. znan. i umjetn., zagreb, 5–20. 93. herak, m. (1995): koncepcijski doseg geologije hrvatske (conceptual scope of the geology of croatia). zbornik ra­ dova prvog hrvatskog geološkog kongresa (opatija), za­ greb, 25–33. 94. herak, m. (1995): znanstveni skup o gjuri pilaru. vjesnik hrv. akad. znan. i umjetn., zagreb, 4/1–3, 166–167. 95. herak, m. (1996): geologija (hrvatske). hrv. leksikon, za­ greb, i, 379. 96. herak, m. (1996): geološka građa (hrvatske). hrv. leksikon, zagreb, i, 379. 97. herak, m. (1996): gjuro pilar prvi rektor prirodoslovac na zagrebačkom sveučilištu. hrv. slovo, društvo hrv. knjiž., za­ greb, ii/57, 30 (prvi dio); ii/58, 30 (drugi dio). 98. gušić, i. & herak, m. (1996): regionalna geologija s paleontologijom (sažetak).– simpozij o fundamentalnim istraživanjima, vjesnik hrv. akad. znan. i umjetn., zagreb, 5/1–3, 58. 99. herak, m. (1997): helmuth zapfe (1913.–1996.).– ljetopis hrv. akad. znan. i umjetn., zagreb, 100, 330–331. geologia croatica 68/3geologia croatica 330 100. herak, m. (1997): naš odnos prema znanosti.– rugjer, za­ greb, 8, 13. 101. herak, m. (1997): croatia.– encycl. of european and asian regional geology (e. m. moores and w. fairbridge, eds.), chapman and hall, london, 155–160. 102. gušić, i. & herak, m. (1997): regionalna geologija s paleontologijom – u nas i u svijetu (regional geology and paleontology – in croatia and abroad).– zbornik radova simp. o fundamentalnim istraživanjima, hrv. akad. znan. i umjetn., zagreb, 199–206. 103. herak, m (1998): vrednovanje znanosti iz aspekta geolog­ ije.–zbornici 2:vidljiva i nevidljiva akademija (d. polšek, ed.). inst. ivo pilar, zagreb, 129–136. 104. herak, m. (2001): razvoj hrvatske geologije 1930.– 1950.– prirodoslovlje, matica hrvatska, zagreb, 279–293. 105. herak, m. (2001): razvoj geologije 1930.–1950.– priro­ doslovlje, matica hrvatska, zagreb, 13–17 1(2), 279–293. 106. herak, m (2006): ljudevit vukotinović između geognoz­ ije i geologije.– zbornik znanstvenog skupa o ljudevitu vukotinoviću farkašu (zagreb, 2003.), 59–68. available online october 31, 2015 2017 | 70/1 | 41–52 | 7 figs. | 2 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction quaternary sediments from the zagreb area were studied in many aspects during the last century (e.g. gorjanovićkramberger, 1907; crnković & bušić, 1970; šimunić & basch, 1975; šimunić et al., 1988; velić & durn, 1993; šikić, 1995; velić et al., 1995; velić et al., 1999), but they are shown most completely on the basic geological map of sfry, 1:100.000, sheet ivanić grad (basch, 1983a, 1983b). pleistocene deposits are represented by aeolian and aquatic-aeolian sediments while in the holocene, deposits are dominated by alluvial and subordinately by deluvial-proluvial sediments. marsh sediments are less abundant. similar distinctions of these sediments are applied on the geological map of the republic of croatia 1:300.000 (2009). similar sediments are described by avanić et al. (2006) from the outcrop near vojnić (fig. 1a), and consist of silts, clays, gravels and sands which were deposited in an alluvial environment and belong to the informal bistra formation. the chronostratigraphic position of this formation is still under debate due to the lack of absolute dating evidence. avanić et al. (2006) suggest that the bistra formation spans a pliocene-pleistocene age. during mapping for the basic geological map of the republic of croatia at 1:50.000 scale, two boreholes: badel-1 (45°82'64''n; 16°09'98''e) at 71.50 m deep and badel-2 (45°82'67''n; 16°10'09''e) at 84.40 m were studied in the area of the former „badel” factory in sesvete (fig. 1). on this map, quaternary sediments are subdivided on the basis of their lithology. in the pleistocene, silts, clays, sands and gravels of the informal bistra formation (bs) are dominant while in the holocene-pleistocene, sands and gravels of the second terrace (t2) are present. the holocene is represented by (a) silts and clays of marsh environments and (b) sands, silts and gravels of alluvial environments. within the investigated sediments of the boreholes, the deep blue mineral vivianite was occurrence of vivianite in alluvial quaternary sediments in the area of sesvete (zagreb, croatia) anita grizelj1, koraljka bakrač1, marija horvat1, radovan avanić1 and ivan hećimović2 1 croatian geological survey, sachsova 2, 10 000 zagreb, croatia; (grizelj.anita@hgi-cgs.hr) 2 anina 29, 10 000 zagreb, croatia doi: 10.4154/gc.2017.01 abstract boreholes badel-1 and badel-2, located in sesvete near zagreb, were drilled through 71.50 and 84.40 m of quaternary sediments, respectively. within these sediments, the occurrence of earthy aggregate and 1-2 mm nodules of the deep blue coloured mineral vivianite was observed. interpretation of the depositional environment, provenance of the sediments and vivianite occurrence was based on sedimentological, mineralogical and palynological analyses. three different facies within the alluvial environments were interpreted: 1) gravels and sands typical of alluvial environments 2) structureless beds of silts and clays deposited in oxbow lakes, marshes and floodplains 3) chaotic sediments deposited in the upper part of the alluvial fan. macroscopically, an earthy aggregate is essentially an occurrence of flattened vivianite crystals grouped in clusters. the studied sediments are the product of intensive weathering of different types of rocks from medvednica mt. with a prevalence of green-schists. rocks from medvednica mt. as the source of ferrous iron (fe2+) and phosphorus (p), and reductive depositional environments can indicate conditions for genesis of vivianite. observed (figs. 3, 4a). vivianite (fe3(po4)2 x 8h2o) is a ferrous iron phosphate mineral which forms in waterlogged soils and aquatic sediments (berner, 1981; bermanec, 1999; rothe et al., 2014, 2016). it is probably the most stable fe2+ orthophosphate mineral in sedimentary environments and in natural systems, stable under ph conditions from 6 to 9 (nriagu, 1972). the precipitation of vivianite often occurs directly from the pore water which contains high concentrations of ferrous iron (fe2+) and soluble reactive p which is found in anoxic non-sulfidic environments (nriagu, 1972; roden & edmonds, 1997). the aim of this article is to determine the sedimentological and mineralogical characteristics of alluvial quaternary sediments in the area of zagreb where vivianite occurs. 2. geological settings the north croatian basin is the south-western part of the pannonian basin system (pbs) (pavelić, 2001) which comprises the biggest part of the central paratethys realm (harzhauser & piler, 2007). medvednica mt., is a neighboring mountain to the study area (fig. 2), and represents one of the inselbergs in the pbs which exposes palaeozoic-mesozoic rocks deformed during cretaceous-palaeogene times and surrounded by miocene sediments (tomljenović et al., 2008). tectonically, it is located in the zagorje-mid-transdanubian shear zone (zmtdz) segment of the sava zone. this part of the sava zone is the area of the connection between the southern-eastern alps, tisia block of the pbs and the internal dinarides (pamić & tomljenović, 1998; herak, 1999; haas et al., 2000; haas & kovács, 2001; pamić 2002, 2003). the core of medvednica mt. is composed mostly of a variety of metamorphic rocks such as metapelites, metapsammites, slatephyllites, slates, quartzites, marbles, blueschists, greenschists of palaeozoic age and more rarely of mesozoic age (belak et al., article history: manuscript received august 09, 2016 revised manuscript accepted november 17, 2016 available online february 20, 2017 keywords: vivianite, quaternary sediments, alluvial, informal bistra formation, zagreb, croatia ide color g eo lo gi a c ro at ic a geologia croatica 70/142 1995, belak & tibljaš, 1998; lugović et al., 2006; tomljenović et al., 2008). mafic extrusive rocks occasionally intersected by dolerite dykes represent the most abundant fragments of oceanic crust in the early callovian to late valanginian ophiolite mélange exposed at medvednica mt. (slovenec & lugović, 2009). metamorphic and non-metamorphic rocks are generally in tectonic relationships except for upper cretaceous and tertiary sediments which are transgressive. the most common mesozoic rocks are limestones and dolomites (basch, 1983b; šikić et al., 1979; šikić, 1995). subordinately, during the mesozoic different clastic sedimentary rocks, radiolarian cherts and, occasionally, pyroclastic and magmatic rocks also occurred (halamić & goričan, 1995; halamić et al., 1999; babić et al., 2002; slovenec & lugović, 2008, 2012). the formation of the pbs commenced in the early miocene due to continental collision and subduction of the european plate beneath the african (apulian) plate. it is surrounded by the alpine, dinaric and carpathian mountain belts (fig. 2) and includes a number of different-sized deep depressions (sub-basins) separated by a comparatively shallow complex of basement rocks (horváth & royden, 1981; royden, 1988). the development of the pbs took place in two phases. the early and middle miocene syn-rift phase of basin development was characterized by tectonic thinning of the crust and isostatic subsidence, while figure 1. a) location map and, b) lithostratigraphic geological map of the sesvete area with locations of boreholes badel-1 (bad-1, 45°82′64′′n; 16°09′98′′e) and badel-2 (bad-2, 45°82′67′′n; 16°10′09′′e) indicated. g eologia c roatica grizelj et al.: occurrence of vivianite in alluvial quaternary sediments in the area of sesvete (zagreb, croatia) 43 the middle and upper miocene post-rift phase was marked by subsidence caused by cooling of the lithosphere (horváth & royden, 1981; royden et al., 1983; royden, 1988, pavelić, 2001). the evolution of neogene sedimentation on medvednica mt. was described in detail by pavelić et al., 2003; avanić et al., 2003; basch, 1983a, 1983b; ćorić, et al., 2009; herak, 2006; kovačić & grizelj, 2006; grizelj et al., 2017; šikić et al., 1977; 1979; šikić, 1995; vrsaljko, 1999; vrsaljko et al., 2006; brlek et al., 2016. according to the aforementioned authors, early miocene sediments unconformably overlie tectonis ed palaeozoic-mesozoic crystalline basement. during the miocene, various types of clastic sediment and limestones were deposited in different marine, brackish and freshwater environments depending on the pbs development. pliocene and quaternary sediments consist of clays, silts, sands and gravels which were deposited in freshwater lakes, swamps and fluvial environments. 3. methods field work included the following: measurement of the thickness of the deposit, defining the type of contacts between intervals, determining the type of sediments and sampling for grain-size analysis (14 samples), mineralogical-petrological and palynological analysis. mineralogical-petrological analysis included the following: microscope analysis of unconsolidated sedimentary rocks (16 samples), x-ray powder diffraction (xrpd), sem-eds analysis of vivianite (1 sample) and measurement of caco3 (14 samples). grain size analyses were performed using a combination of sieving and aerometric methods. the nomenclature according to trefethen (1950) and konta (1973) was used for the classification of sediments. preparation for qualitative and quantitative mineralogical analyses of the light and heavy mineral fraction of silty and sandy samples included the following: carbonate fraction dissolution with 4% cold hydrochloric acid, separation of the 0.09–0.045 mm mineral fraction from the sandy and silty sediments using sieves, separation of the heavy and light mineral fraction using bromoform (chbr3; δ=2.84 gcm-3). analyses were performed by determination of 300-400 grains per sample using the ribbon counting method according to mange & maurer (1992). preparation of coarser sand and fine gravel samples included separation by sieves 2.80 mm, 1.25 mm and 0.90 mm fraction. for xrpd analysis, individual grains of vivanite were separated using a stereomicroscope and needle. xrpd patterns were recorded on a philips vertical goniometer (type x`pert) equipped with a cu-tube using the following experimental conditions: 45 kv, 40 ma, pw 3018/00 pixcel detector, primary beam divergence 1/4° and continuous scan (step 0.02 º2θ/s). sem-eds analysis was carried out on the jeol multi-purpose scanning microscope (jsm-35). morphologic analyses were performed at 20kev accelerating potential and 90-ma filament current. compositional analyses by energy dispersive spectrometry (eds) utilized a liquid nitrogen cooled incax-act oxford instruments detector with the microscope operating at 20-kev figure 2. pannonian basin system (pbs) and its surroundings with the locations of the study-area marked in red. based on http://maps-for-free.com/. g eo lo gi a c ro at ic a geologia croatica 70/144 figure 3. a detailed geological column of quaternary clastic sediments from boreholes badel-1 and badel-2. g eologia c roatica grizelj et al.: occurrence of vivianite in alluvial quaternary sediments in the area of sesvete (zagreb, croatia) 45 potential and 90-ma current. caco3 was measured using the collins calcimeter. standard palynological processing techniques (faegri & iversen, 1989; moore et al., 1991) were used to extract the organic matter. the samples were treated with sodium pyrophosphate (na4p2o7), hydrochloric acid (hcl, 15%), and hydrofluoric acid (hf, 40%), to remove the clay minerals, carbonates and silica, respectively, followed by separation of the organic residue by means of zinc chloride (zncl2, specific gravity 2.0). the residue was sieved at 10 µm using a nylon mesh. microscope slides were prepared using glycerin for palynofacies analysis, and with silicone oil for palynomorph analysis. pollen identification was carried out under an olympus bh-2 transmitted light microscope at x400, x600 and x1000 (oil immersion) magnifications combined with the interference contrast. fluorescence was used in order to distinguish reworked palynomorphs. photos were taken using a moticam 2300. palynological residues and slides are stored in the collection of the croatian geological survey. all analyses were made at the croatian geological survey (croatia, zagreb). 4. results and discussion 4.1. description and interpretation of facies geological investigations consisted of petrographic and sedimentological determination of the boreholes, mineralogical investigation of vivianite and definition of a stratigraphic affiliation of the deposits based on palynological analyses. a detailed geological column of the investigated boreholes is shown in figure 3. vivianite was found at depths up to 15.20 m in sediments of the boreholes badel-1 and badel-2 (figs. 1, 3, 4a). drilled deposits are grouped into three facies: a) gravels and sands, b) structureless beds of silts and clays, and c) chaotic sediments. 4.1.1. gravels and sands facies gravels and sands form decimetre to metre thick lenses and interbeds which overlie structurless silts and clays beds with an erosional lower boundary. in some interbeds, clast-supported gravels show the tendency of fining upwards, from fine-grained and sandy gravel in the lower part to silty and clayey sands in the upper part. the matrix is poorly sorted gravelly sand, silty sand or very rarely, silts. pebbles are mostly 0.2 to 2 cm in diameter. sands form interbeds from 0.5 to 6 m thick or lenses changing into interbeds of gravels. they are fine to coarse-grained, poorly sorted, and horizontally bedded. within the gravelly sand, blue earthy aggregates and 1-2 mm size nodules of oxidizes vivianite were observed (figs. 3 and 4a). their presence was demonstrated by xrpd and eds analyses (fig. 4b and 4d). macroscopically, earthy aggregate is essentially an occurrence of flattened vivianite crystals up to 6 mm in size, grouped into clusters (fig. 4c). the occurrence of vivianite is linked to oxidation-reduction reactions in sediments (rothe et al., 2016). it appears when pore waters have sufficiently high orthophospate and fe2+ concentrations and s2is not present in high amounts (nriagu, 1972; rothe et al., 2015). the grain size, clast-supported nature of the gravel, its poor sorting and the erosional lower boundary, together indicate high sediment concentration flows and deposition in stream channels (nemec & steel, 1984). the associated sands are interpreted as having been deposited from sheetflows (nemec & kafigure 4. vivianite from sample bad-1/14.60-15.20 m; a) photo showing a mineral aggregate in sediment, b) xrpd pattern of the separated material (viv – vivianite, qtz – quartz, ms – muscovite), c) sem image – flattened crystals up to 6 mm length, d) eds spectrum of elemental analysis. g eo lo gi a c ro at ic a geologia croatica 70/146 zanci, 1999). the sandy matrix, upwards fining tendency and sandy lenses suggests deposition by a waning flow. such frequent vertical and lateral changes of sand and gravel are typical of alluvial environments (miall, 1996, 2000). 4.1.2. facies of structureless beds of silts and clays structureless beds of silts and clays overlie gravel and sand facies or the facies of chaotic sediments. they contain fragments of flora and fauna, coal and earthy vivianite aggregate (fig. 3). earthy aggregate of vivianite is sporadically present in the sediments at depths down to 15 m as a short linear zone or dots which are macroscopically visible. the caco3 content varies from 3.3 to 47.3 % (tab. 1). these sediments are poorly to very poorly sorted. based on their caco3 content and grain size they are classified as clayey silts, calcareous clayey silts, silts, calcareous sandy clayey silts and calcareous sandy silts (tab. 1). the grain size of silts and clays suggests that they were deposited from suspension on the flood plain. in association with coarse-grained alluvial facies, these sediments could be deposited in oxbow lakes and marshes, similar to pliocene-pleistocene sediments described nearby vojnić (avanić et al., 2006). 4.1.3. facies of chaotic sediments chaotic sediments are deposited on structureless silts and clays. the lower bedding plane is uneven. they are characterized by internal disorganization, poorly sorting, and a wide range of grain sizes, from coarse gravel to clay-sized particles. these characteristics of the deposits indicate a debris flow (nemec & steel, 1984), which may point to a proximal alluvial fan, or to the outcome of a sudden destabilization of previously deposited unconsolidated material (nemec & postma, 1993). 4.2. content of heavy and light minerals table 1. shows the results of modal analyses of the heavy and light mineral fractions from the sandy-silty fraction of samples (fig. 3). samples are dominated by grains from the light mineral fraction (lmf). quartz is the most common mineral in the lmf and its content varies from 40 to 87 %. grains with low undulatory extinction prevail while grains with homogeneous extinction are rare. the amount of rock fragments varies from 2 to 54 %. among them, low-grade metamorphic schists are the most abundant. chert, quartzite and tuffs are less abundant. the amount of k-feldspars varies from 2 to 12 %. muscovite is present in a very small quantity in almost all samples (tab. 1). samples bad-1/4.30 m and bad-2/12.40 m contain a small amount of sponge spicules. translucent minerals prevail in the heavy mineral fraction (hmf) in all samples, followed by opaque minerals (magnetite and limonite), while chlorite is less abundant. samples bad1/25.00 m and bad-2/62.00 m contain a small amount of biotite. among the translucent minerals in the hmf the minerals from the epidote group (epidote, zoisite, clinozoisite) are dominant in most samples, ranging from 24 to 95 % (tab. 1). epidote appears as allotriomorphic grains with weakly expressed pleochroism, with pale yellow to yellowish green colour (fig. 5 a-e). other significant minerals in the hmf (tab. 1) are garnet (fig. 5 b-e) and staurolite (fig. 5 d). garnet occurs as pale pink-coloured, irregular grains. staurolite appears as allotriomorphic grains with noticeable pleochroism, in pale yellow to dark yellow colours. tourmaline, zircon rutile, amphiboles and kyanite (fig. 5) are present in almost all samples, while titanite, chloritoid, pyroxene and brookite are present in some samples (tab. 1). tourmaline (dravite type) (fig. 5 b) occurs in the form of allotriomorphic, rarely hypidiomorphic crystals with strong pleochroism, in dark brown to brown colours. zircon appears as colourless, rounded ta bl e 1. m od al co m po sit io n of th e he av y an d lig ht m in er al fr ac tio ns o f t he sa m pl e fro m b or eh ol es b ad el -1 (b ad -1 ) a nd b ad el -2 (b ad -2 ) d et er m in ed b y po la riz in g m ic ro sc op e. o p – op aq ue m in er al s, bt – b io tit e, c hl – ch lo rit e, th m – tr an slu ce nt h ea vy m in er al s, tu r – to ur m al in e, z rn – zi rc on , r t – ru til e, a m – a m ph ib ol e, p x – py ro xe ne , e pzo -c zo – e pi do te , z oi sit e, cl in oz oi sit e, g rt – g ar ne t, ky – k ya ni te , s t – s ta ur ol ite , t tn – ti ta ni te , b rk – b ro ok ite , c lo – c hl or ito id , o th . – o th er m in er al s, q tz – q ua rt z, kf s – k -fe ld sp ar , s – ro ck fr ag m en ts (s ch ist s, ch er t, an d qu ar tz ite ), m s – m us co vi te , s p – sp on ge sp ic ul es , + – tr ac es (< 1% ), * – c ac o 3 ( w t. % ) a na ly se d by c ol lin s c al ci m et er . sa m pl e sa m pl e d es cr ip ti o n ca co 3 (w t. % )* % h ea vy m in er al fr ac ti o n h ea vy m in er al s (% ) tr an sl u ce n t h ea vy m in er al s (% ) li g h t m in er al s (% ) o p bt ch l th m tu r zr rt am p px ep -z ocz o g rt ky st tt n br k cl d o th . q tz kf s s m s sp ba d1/ 4. 30 m sil t 3. 3 pr ep . 31 6 63 2 2 6 6 24 41 3 12 + 2 87 3 2 8 + ba d1/ 8. 00 m cl ay ey si lt 4. 2 2. 1 29 + 71 1 4 1 + 89 3 + 1 2 72 10 17 1 ba d1/ 9. 00 m si lty g ra ve lly sa nd 4. 2 3. 8 23 + 77 + 2 6 81 5 + 1 + + 1 62 4 33 1 ba d1/ 25 .0 0 m ca lc ar eo us c la ye y sil t 27 .6 pr ep . 25 + 1 72 3 1 5 3 61 11 2 10 2 + 2 82 6 8 4 ba d1/ 39 .4 0 m g ra ve lly si lty sa nd 3. 3 7. 7 7 93 5 2 1 + 81 7 + 3 1 86 4 10 + ba d1/ 47 .4 0 m ca lc ar eo us c la ye y sil t 18 .4 4. 3 7 1 92 1 + 1 93 4 + 1 + 1 73 2 24 + ba d1/ 55 .4 0 m g ra ve lly si lty sa nd 7. 5 18 .4 8 92 1 1 + 97 + + 70 6 24 + ba d1/ 71 .0 0 m ca lc ar eo us sa nd y cl ay ey si lt 11 .3 8. 0 6 + 94 1 + + 1 89 3 + 3 + 1 74 7 19 + ba d2/ 4. 00 m ca lc ar eo us sa nd y sil t 32 .1 0. 8 32 68 2 2 7 1 + 36 36 4 9 + + 2 76 7 17 ba d2/ 12 .4 0 m cl ay ey si lt 8. 0 1. 6 24 1 75 3 1 1 6 64 16 + 6 + 2 67 6 27 + + ba d2/ 2 1. 00 m ca lc ar eo us si lty sa nd y gr av el 47 .3 4. 2 13 + 87 1 + 1 2 86 5 1 2 + 1 62 11 17 ba d2/ 44 .5 0 m ca lc ar eo us g ra ve lly sa nd 21 .1 8. 4 5 4 91 1 1 3 94 1 + + 40 6 54 + ba d2/ 62 .0 0 m ca lc ar eo us si lty g ra ve lly sa nd 17 .8 8. 1 9 + 91 1 + 1 91 5 + 1 1 76 7 17 + ba d2/ 84 .0 0 m ca lc ar eo us c la ye y sil t 12 .2 8. 2 4 96 + + 2 95 1 + 1 + 75 12 13 + g eologia c roatica grizelj et al.: occurrence of vivianite in alluvial quaternary sediments in the area of sesvete (zagreb, croatia) 47 grains, very rarely as idiomorphic, prismatic grains (fig. 5 a). amphiboles are pale green to brownish green prismatic crystals with expressed prismatic cleavage. 4.3. analyses of the sandy fraction (0.90–1.25 mm) and sandy-gravelly fraction (1.25–2.80 mm) sample bad-1/9.00 m in the sand and sandy to gravelly fractions of the investigated sample bad-1/9.00 m particles of the rocks from greenschist facies prevail. they are represented by metabasic rocks rich in the epidote-actinolite-plagioclase mineral assemblage. more common are various varieties of quartzite (synmetamorphic quartz mainly) (figs. 6 a, b). particles of black metapelites and metapsammites are less abundant. micrite to microsparite carbonate particles are also rare. these carbonate particles differ from carbonate particles found at deeper levels and their possible origin could very likely be correlated to cretaceous (?) limestones from the area. sample bad-1/15.00 m the sample bad-1/15.00 m of the sand and sandy to gravelly fractions dominantly consist of black metapelites and metapsamfigure 5. photomicrographs of the heavy mineral fraction: a, b, c) sample bad-1/39.40 m, analyser off; d, e) sample bad-1/47.40 m, analyser off; f) sample bad2/62.00 m, analyser off. mineral abbreviations are the same as in table 1. g eo lo gi a c ro at ic a geologia croatica 70/148 mites. organic matter is the main component of these particles (which is visible macroscopically and microscopically) and depending on their degree of metamorphism they could be determined as meta-anthracite or graphite (?) figs. 6 c, d. in addition, a large amount of quartz particles is present (synmetamorphic quartz) (figs. 6 c). sandstones and metasandstones without the organic matter and carbonate particles (represented by recrystallized limestone fragments or marble) are not so common. the sand fraction of the investigated sample contains two goethite particles. only a few rock fragments belonging to the greenschist facies were discovered. they contain epidote, actinolite and plagioclase needles. the composition of the hmf, (sandy fraction 0.90 – 1.25 mm and sandy-gravelly fraction 1.25 – 2.80 mm) of the samples suggest that the source rocks were from the medvednica mt. palaeozoic metamorphic rock forms the base structure and the most common rocks of medvednica mt. according to lugović et al. (2006) the greenschist facies which crops out on the southern slopes of the medvednica mt. consists of metabasites overlain by metasediments (metapelites, meta arenites, marbles, metatuffites). these rocks were the main source of material for clastic rocks from badel-1 and badel-2 boreholes as well as the informal bistra formation. amphibolite and chloritoid schists, metagabbros, metadiabases, slates, phyllites, dolomites, limestones, radiolarian cherts, pyroclastics, magmatic and different clastic sedimentary rocks, which are also present on medvednica mt. (šikić et al., 1977; 1979, šikić, 1995; basch, 1983a, 1983b; herak, 2006) contributed in a minor amount as parent rocks to the informal bistra formation. 4.4. palynology four samples for pollen analysis (three from badel-1 at 9.70 m, 58.20 m and 59.00 m depth, and one from badel-2 at 18.40 m depth) were taken from the fine-grained samples, (i.e. silt and clay) containing more or less organic components. the main characteristic of the analyzed samples is the absolute dominance of the structured phytoclasts in the total organic residue that indicates a pronounced fluvial input of terrestrial organic components, and relatively short transport based on the structure, angularity and size of the organic clasts. mechanical damage of the palynomorphs is the consequence of redeposition of older sediments (mainly miocene). such redeposition is common in glacial environments (birks & birks, 1980), when redeposited palynomorphs from eroded interglacial deposits are observed in silt and clay together with quaternary palynomorphs. all samples contain palynomorphs (tab. 2; fig. 7). a mi nimum of 200 palynomorphs couldn’t be reached only in badel-1/9.70 m because there wasn’t enough organic residue. unfortunately, pollen concentration wasn’t measured because the first intention was to check the environment and when material became promising palynomorphs were counted. the degree of preservation of the grains is medium to good, i.e. some grains’ figure 6. photomicrographs of the sand and sandy to gravelly fraction aggregates of the investigated samples: a, b) sample bad-1/9.00 m; c, d) sample bad1/15.00 m (detailed description see in the text). g eologia c roatica grizelj et al.: occurrence of vivianite in alluvial quaternary sediments in the area of sesvete (zagreb, croatia) 49 2000). spores of the planktonic algae sigmopollis are an indicator of the slowly-moving shallow eutrophic to mesotrophic fresh water environment (pals et al., 1980, van geel et al., 1989). due to vegetational succession, boreal mires alter to heathland. in the sample badel-1/58.20 m the moss genus sphagnum and algae sigmopollis completely disappear, conifer pinus decrease (52%) while the share of polypodium-type fern increases (13%). redeposited dinocysts (2%) confirm erosion of the older sediments (i.e. miocene). sample badel-1/9.70 m from the upper part of the core contains a very small amount of organic residue of a mixed composition. sporomorphs are rare with only 52 specimens: conifer (56%), fern spore polypodium-type (10%), quercus (10%), graminae, cyperaceae pollen, larix, and redeposited dinoflagellate cysts (polysphaeridium) were determined, indicating open vegetation, erosion and deposition on the floodplain. similar vegetation was also growing around lake bled during the younger dryas (andrič et al, 2009). in badel-2 only one sample was analyzed from 18.40 m deep. it is also dominated by conifer pollen (43%) and cyperaceae (23%) but the proportion of algae (8%) is significant. the occurrence of zygospores of spirogyra, zygnema and mougeotia in the quaternary deposits indicates a shallow eutrophic water body with warm pluvial periods which supplied fluvial sediments (medeanic, 2006, van geel et al., 1989, worobiec, 2014). in the zygnemataceae, zygospore formation occurs mostly during the spring season in clean, oxygen-rich, shallow fresh water (van geel, 1976). the optimal temperature for zygnema is 15–20°c, and for most species of spirogyra the optimum is 14–22°c (hoshaw, 1968). such high temperatures are easily reached in shallow water exposed to direct solar radiation, at least during the warm season (van geel, 1978). a ph value of 7.0–8.0 was inferred from the zygospores of spirogyra (grote, 1977). spores of the planktonic algae sigmopollis (22%) are an indicator of meso-oligotrophic slower stream to calm water environments (van geel et al., 1989). the alga mougeotia is one of the most common freshwater algae, and is common from arctic to tropical areas, in lakes, springs and streams, and even in occasional ponds, where it appears as the first alga after the rainy season (transeau, 1926). zygnemataceae, especially mougeotia, dominate in acidic lakes (turner et al., 1995; graham et al., 1996). according to the köppen’s classification, the climate was most likely humid boreal (df) during deposition of samples badel-1/58.20 m, badel-1/59.00 m and badel-2/18.40 m and dry boreal (dw) during the deposition of sample badel-1/9.70 m (šegota & filipčić, 2003). 4.5. origin of vivianite the occurrence of vivianite in sediments of the informal bistra formation is not a ubiquitous occurrence and it is not indicative for these deposits according to field investigations during geological mapping. one of the most important factors of vivianite formation is a sufficiently high concentration of orthophospate and fe2+ in the pore waters (nriagu, 1972). the presence of limonite and magnetite in the hmf of sandy and silty fractions, fe-mn concretions in sediments as a source of fe phases, high content of phosphorus (p) in stream sediments of some creeks from medvednica mt. (galović et al., 2012), and reducing conditions, as seen from the gray colour of sediments and palynomorphs of the investigated samples were some of the prerequisites for vivianite formation. a variety of factors are of primary importance and may affect vivianite formation as well, such as redox conditions, degstructure and sculpture are partially destroyed making more precise determination impossible. the plant community is relatively poor in species. the polypodium-type is among the most resistant sporomorphs to corrosion, containing the most sporopollenin (havinga, 1964, 1984), and therefore it is common in samples that are scarce in palynomorphs. tertiary relicts (e.g. carya whose pollen is very resistant), except redeposited forms, were not observed, which could indicate that the samples are probably of the younger pleistocene age. frigophile vegetation indicates a cold period. since the cold stage flora is quite uniform (šercelj, 1979) it is difficult to classify the deposits to particular glacial, and/or stadial, in the case when they are not linked to the previous or following warmer period. the oldest sample from the core badel-1 at 59.00 m is dominated by conifer pollen. pinus, the most abundant (68%), and picea (6%) were brought in the depositional environment by wind or streams. less abundant is fern polypodium-type (6%) and moss sphagnum (2%) spores that prevailed in the acidified (ph 3-4) mires belonging to the boreal floral element. boreal mires favour a moderately cold and humid climate, so when the ice started to melt after the last ice age in europe, 10000 years ago, it covered a huge area. wetter weather and higher sea levels combined to raise groundwater tables everywhere, so that large mires arose in poorly drained lowlands and basins (raeymaekers, table 2. distribution of palynomorphs. sample: badel-1 9.7m badel-1 58.2m badel-1 59.0m badel-2 18.4m palynomorphs: a b(%) a b(%) a b(%) a b(%) polypodium 5 10 26 13 22 6 pteridium 1 0 6 2 sphagnum 7 2 lycopodium 8 4 2 1 bisaccites gen et sp indet. 10 19 11 5 7 2 25 7 pinus 19 37 106 52 225 66 153 43 picea 13 6 22 6 24 7 larix 2 4 3 1 11 3 5 1 quercus 5 10 1 0 graminae 2 4 2 1 2 1 6 2 asteraceae 1 2 4 2 4 1 7 2 cichoriaceae 3 1 6 2 cyperaceae 1 2 9 4 83 23 caryophyllaceae 2 1 mimosaceae 4 1 sigmopollis 3 1 12 3 zygnema 1 0 6 2 spirogyra 3 1 11 3 mougeotia 1 0 tilletia 1 2 dinocyst 4 8 5 2 1 0 unknown 2 4 15 7 21 6 13 4 total palynomorphs sum 52 100 204 100 339 100 359 100 columns a – number of identified palynomorphs per samples columns b – percentages of palynomorphs per samples g eo lo gi a c ro at ic a geologia croatica 70/150 radation potential of organic matter, microbial community composition, resorption potential by remaining fe(iii) (oxyhydr)oxides and silicate clays, orthophosphate release, temperature and ph (rothe et al., 2016). it is obvious that if some of the above mentioned factors are not present, vivianite will not occur. additionally, there is the possibility that a very small amount of vivianite present in the sample/sediment cannot be detected. although vivianite has been detected in many anthropogenically influenced sedimentary settings (goslar et al., 1999; rothe et al., 2015, 2016), in the case of the analyzed samples such influence is hardly possible. one of the reasons is low clayey silts water permeability above the horizons in which vivianite occurres (fig. 3). another reason could be that in many freshwater systems, an increased nutrient supply led to accelerated eutrophication, a change in oxygen and redox conditions and the appearance of s2in the water column, indicating a loss of fe and p binding capacity of the sediments (rothe et al., 2016). according to rothe et al. (2015), vivianite is in some cases present only in pre-industrial sediments with low ranges of nutrient levels, organic matter production and sulphur supply during its deposition. in the area of zagreb, vivianite nodules were recorded in another borehole near the „dioki” factory at 44.80 m depth (unpublished data). the presence of vivianite in deep sediment layers demonstrates that vivianite can persist for many thousands of years within the sediments (rothe et al., 2016). 5. conclusion analysed quaternary sediments from boreholes badel-1 and badel-2 were grouped into three facies deposited in alluvial environment: figure 7. photomicrograph of determined palynomorphs: badel-2/18.40 m: a) pinus, b) cyperaceae, c) asteraceae, d) graminae, e) zygnema, f) spirogyra; badel-1/9.70 m: g) pinus, h) polypodium-type, i) polysphaeridium, j) cyperaceae, k) asteraceae, l) quercus; badel-1/58.20 m: m) picea, n) pinus, o) polypodium-type, p) phytoclasts and badel-1/59.00 m: r) sphagnum and pinus, s) picea, t) polypodium-type, u) sigmopollis. scale bar = 10 µm except on p) = 50 µm. g eologia c roatica grizelj et al.: occurrence of vivianite in alluvial quaternary sediments in the area of sesvete (zagreb, croatia) 51 1) gravel and sand deposits typical of alluvial environments 2) structureless beds of silts and clays deposited in oxbow lakes, marshes and on floodplains 3) chaotic sediments deposited in the upper part of the alluvial fan. below the first two facies at a depth up to 15.20 m earthy aggregates and nodules of vivianite were determined. sem analyses revealed flattened crystal clusters up to 6 mm length. vivia nite occurrence is associated with the presence of limonite, magnetite and fe-mn concretions in sediments as a source of fe phases, a high content of phosphorus (p) in the stream sediments of some creeks from medvednica mt., and reducing conditions as suggested by the palynomorphs of the investigated samples. deposition of the sediments based on the samples analysed for palynology (from sediments both underlying and overlying those with vivianite) most probably occurred in a marshy environment (badel-2/18.40 m; badel-1/59.00 m; badel-1/58.20 m) with periodic fluvial input of terrestrial organic components, as well as on sandbanks and wet meadows on a f loodplain (badel-1/9.70 m). according to the köppen classification, based on palynology, the climate was most likely humid boreal (df) during deposition of samples badel-1/58.20 m, badel-1/59.00 m and badel-2/18.40 m and dry boreal (dw) during deposition of the sample badel-1/9.70 m. acknowledgement this study was supported by the ministry of science, education and sports, republic of croatia, project no. 181-1811096-1093 and the croatian science foundation project no. 4425. we are very thankful to branko hlevnjak (university of zagreb, faculty of mining, geology and petroleum engineering) for access to the borehole sediments. special thanks also go to mirko belak (croatian geological survey) for the discussion on the origin of the material and dario hruševar for discussion on vegetation cover. we appreciated the contributions by nenad to mašić (university of zagreb, faculty of science) for graphite coating and processing of the samples for sem-eds analysis, nenad kurtanjek for preparing fig. 1., vlasta jurišić mitrović for chemical treatments, mirjana drušković, dragica kovačić, antun škrtić and damir galović (croatian geological survey) for sample preparation. language editing was undertaken by lara wacha and zoran peh (croatian geological survey) and language editor julie robson which has improved the quality of expression, for which we thank them. we are very grateful to maja andrič, davor pavelić and an anonymous reviewer for their valuable and helpful comments. references andrič, m., massaferro, j., eicher, u., ammann, b., leuenberger, m.c., martinčič, a., marinova, e. & brancelj, a. (2009): a multiproxy lateglacial palaeoenvironmental record from lake bled, slovenia.– hydrobiologia, 631, 121–141. avanić, r., bakrač, k., grizelj, a., wacha, l., šimić-stanković, m., hećimović, lj., tibljaš, d. & kruk, b. (2006): ivošević gaj ceramic clay deposit in the vicinity of vojnić.– in: vlahović, i., tibljaš, d. & durn, g. (eds.): 3rd mid-european clay conference, opatija, field trip guidebook, 39–47. avanić, r., kovačić, m., pavelić, d., miknić, m., vrsaljko, d., bakrač, k., galović, i. (2003): the midle and upper miocene facies of mt. medvednica (northern croatia).– in: vlahović, i. & tišljar, j. (eds.): evolution of depositional environments from paleozoik to the quarternary in the karst dinarides and the pannonian basin, 22nd ias meeting of sedimentology.opatija, field trip guidebook, 167–172. babić, lj., hochuli, p.a. & zupanič, j. (2002): the jurassic ophiolitic melange in the ne dinarides: dating, internal structure and geotectonic implications.– eclogae geologicae helvetiae, 95, 263–275. basch, o. (1983a): osnovna geološka karta sfrj 1:100000, list ivanić grad l33-81 [basic geological map of sfry, 1:100000. ivanić grad sheet – in croatian].– geološki zavod zagreb, savezni geološki zavod beograd. basch, o. (1983b): osnovna geološka karta sfrj 1:100000, tumač za list ivanić grad [basic geological map of sfry, 1:100000, geology of the ivanić grad sheet – in croatian].– geološki zavod zagreb, savezni geološki zavod beograd, 66 p. belak, m. & tibljaš, d. (1998): discovery of blueschists in the medvednica mountain (northern croatia) and their significance for the interpretation of the geotectonic evolution of the area.– geol. croatica, 51/1, 27–32. doi: 10.4154/gc.1998.05 belak, m., pamić, j., kolar-jurkovšek, t., peckay, z. & karan, d. (1995): alpinski regionalmetamorfni kompleks medvednice (sjeverozapadna hrvatska).– in: vlahović, i., velić, i. & šparica, m. (eds.): 1st croatian geologic congress, opatija, proceedings, 1, 67–70. bermanec, v. (1999): sistematska mineralogija – mineralogija nesilikata [system of mineralogy – silicate minerals – in croatian].– targa, zagreb, 264 p. berner, r.a. (1981): a new geochemical classification of sedimentary environments.– j. sediment. res., 51, 359–365. birks, h.j.b & birks, h.h. (1980): quaternary palaeoecology.– (reprinted 2004 by the blackburn press, new jersey) edward arnold, london. brlek, m., špišić, m., brčić, v., mišur, i. kurečić, t., miknić, m., avanić, r., vrsaljko, d. & slovenec, d. (2016): mid-miocene (badenian) transgression on mesozoic basement rocks in the mt. medvednica area of northern croatia.– facies 62/3, 1–21. doi: 10.1007/s10347-016-0470-z. ćorić, s., pavelić, d., rögl, f., mandić, o., vrabac, s., avanić, r. & vranjković, a. (2009): revised middle miocene datum for initial marine flooding of north croatian basins (pannonian basin system, central paratethys).– geologia croatica, 62, 31–43. doi: 10.4154/gc.2009.03 crnković, b. & bušić, m. (1970): mineraloško-petrografski nanos rijeke save. [mineralogical-petrological sediments of river sava – in croatian].– zbornik radova rud. geol. naftnog fakulteta. sveučilišta u zagrebu u povodu 30 god. rada (1939–1969). 133–140. croatian geological survey (2009): geological map of the republic of croatia 1:300000.– department of geology, zagreb. faegri, k. & iversen, j. (1989): textbook of pollen analysis. (4th edition by faegri, k., kaland, p.e. & krzywinski, k. (eds.).− john wiley & sons new york, 328 p. galović, l., peh, z., halamić, j. & bukovec, d. (2012): geochemical atlas of the medvednica mt.: natural distribution of geochemical elements in stream sediments.– journal of maps, 8/4, 478–483. doi: 10.1080/17445647.2012.741833. gorjanović-kramberger, d. (1907): dali je gora bila zagrebačka odleđena i kako je postala zagrebačka terasa [was the zagreb mt. thawed and how the zagreb terasa originate – in croatian].– glasn. hrv. naravosl. društva, 19, 37–43. goslar, t., ralska-jasiewiczowa, m., van geel, b., ��cka, b., szerovan geel, b., ��cka, b., szero-van geel, b., ��cka, b., szeroczyńska, k., chróst, l. & walanus, a. (1999): anthropogenic changes in the sediment composition of lake gościąż (central poland), during the last 330 yrs*.– journal of paleolimnology, 22, 171–185. grote, m. (1977): über die auslösung der generativen fortpflanzung unter kontrollierten bedingungen bei der grünalge spirogyra majuscule.– z-pflanzenphysiol., 83, 95–107. graham, j.m., arancibia-avila, p. & graham, l.e. (1996): physiological ecology of a species of the filamentous green alga mougeotia under acidic conditions: light and temperature effects on photosynthesis and respiration.– limnology and oceanography, 41/2, 253–262. grizelj, a., peh, z., tibljaš, d., kovačić, m. & kurečić, t. (2017): mineralogical and geochemical characteristics of miocene pelitic sedimentary rocks from the south-western part of the pannonian basin system (croatia): implications for provenance studies.– geoscience frontiers, 811, 65–80. doi: 10.1016/j.gsf.2015.11.009 harzhauser, m & piller, w.e. (2007): benchmark dana of a changing sea – paleogeography, paleobiogeography and events in the central paratethys during the miocene.– paleogeogr. paleoclimatol. paleoecol., 253, 8–31. haas, j. & kovács, s. (2001): the dinaridic-alpine connection – as seen from hungary.– acta geol. hung., 44, 345–362. haas, j., mioč, p., pamić, j., tomljenović, b., árkai, p., bérczi-makk, a., korokna, i. b., kovács, s. & r.-felgenhauer, e. (2000): complex structural pattern of the alpine-dinaridic pannonian triple junction.– int. j. earth sci., 89, 377–389. doi: 10.1007/s005310000093 halamić, j. & goričan, š. (1995): triassic radiolarites from mts. kalnik and medvednica (northwestern croatia).– geologia croatica, 48/2, 129–146. doi: 10.4154/ gc.1995.10 halamić, j., goričan, š., slovenec, d. & kolar-jurkovšek, t. (1999): a middle jurassic radiolarites-clastic succession from the medvednica mt., nw croatia.– geologia croatica, 52/1, 29–57. doi: 10.4154/gc.1999.03 havinga, a.j. (1964): an investigation into the differential corrosion susceptibility of pollen and spores.– pollen spores, 6, 621–635. havinga, a.j. (1984): a 20-year experimental investigation into the differential corrosion susceptibility of pollen and spores in various soil types.– pollen spores, 26, 541–558. g eo lo gi a c ro at ic a geologia croatica 70/152 herak (1999): tectonic interrelation of the dinarides and the southern alps.– geol. croatica, 52, 83–98. doi: 10.4154/gc.1999.07 herak, m. (2006): medvednica. zagonetno zagrebačko gorje [enigmatic zagreb mountains – in croatian, english summary].– hrvatski geološki institut, zagreb, 195 p. horvath, f. & royden, l.h. (1981): mechanism for the formation of the intracarpathian basins: a review.– earth science reviews, 3–4, 307–316. hoshaw r.w. (1968): biology of the filamentous conjugating algae.– in: jackson d.f. (ed.): algae, man and environment. syracuse university press, 135–184. konta, i. (1973): kvantitativní systém reziduálních hornin, sedimentů a vulkanoklastických usazenin. [quantitative system of residual rocks, sediments and volcanoclastic deposits – in czech].– univ. karlova, praha, 1–375. kovačić, m. & grizelj, a. (2006): provenance of the upper miocene clastic material in the southwestern part of the pannonian basin.– geologica carpathica, 57/6, 495–510. lugović, b., šegvić, b. & altherr, r. (2006): petrology, geochemistry and tectonic significance of the orthogreenschists from the sw zagorje-mid-transdanubian zone (medvednica mts, croatia).– ofioliti, 39/1, 31–50. menge, m.a. & maurer, h.f.w. (1992): heavy minerals in colour.– chapman & hall, london, 1–151. doi: 10.1007/978-94-011-2308-2 medeanic, s. (2006): freshwater algal palynomorph records from holocene deposits in the coastal plain of rio grande do sul, brazil.– rev. palaeobot. palynol., 141, 83–101. doi: 10.1016/j.revpalbo.2006.03.012 miall, a.d. (1996): the geology of fluvial deposits. sedimentary facies, basin analysis and petroleum geology.– springer-verlag, heidelberg, 582 p. miall, a.d. (2000): principles of sedimentary basin analysis.– 3rd ed., springer-verlag, berlin-heidelberg, 616 p. doi: 10.1007/978-3-662-03999-1 moore, p.d., webb, j.a. & collinson, m. (1991): pollen analysis (second edition).− blackwell sci. publication, london, 216 p. nemec, w. & kazanci, n. (1999): quaternary colluvium in west-central anatolia: sedimentary facies and palaeoclimatic significance.– sedimentology, 46, 139–170. doi: 10.1046/j.1365-3091.1999.00210.x nemec, w. & postma, g. (1993): quaternary alluvial fans in southwestern crete: sedimentation processes and geomorphic evolution.– in: marzo, m. & puig-– in: marzo, m. & puigin: marzo, m. & puigdefábregas, c. (eds.): alluvial sedimentation. ias spec. publs, 17, 235–276. doi: 10.1002/9781444303995.ch18 nemec, w. & steel, r.j. (1984): alluvial and costal conglomerates: their significant features and some comments on gravelly mass-flow deposits.– in: coster, e.h. & steel, r.j. (eds.): sedimentology of gravels and conglomerates. can. soc. petrol. geologists mem., 10, 1–31. nriagu, j.o. (1972): stability of vivianite and ion-pair formation in the system fe3(po4)2–h3po4–h2o.– geochim. cosmochim. acta, 36, 459–470. pals, j.p., van geel, b. & delfos, a. (1980): palaeocological studies in the klokkeweel bog near hoogkarspel (prov. of noord holland).– rev. palaeobot. palynol., 30, 371–418. pamić, j. (2002): the sava-vardar zone of the dinarides and hellenides versus the vardar ocean.– eclogae geol. helv., 95, 99–113. pamić, j. (2003): the allochthonous fragments of the internal dinaridic units in the western part of the south pannonian basin.– acta geol. hung. 46, 41–62. pamić, j. & tomljenović, b. (1998): basic geologic data from the croatian part of the zagorje-mid transdanubian zone.– acta geol. hung., 41, 389–400. pavelić, d. (2001): tectonostratigraphic model for north croatian basin and north bosnia (miocene, pannonian basin system).– basin research, 13, 359–376. pavelić, d., avanić, r., kovačić, m., vrsaljko, d. & miknić, m. (2003): an outline of the evolution of the croatian part of the pannonian basin system.– in: vlahović, i. & tišljar, j. (eds.): 22nd ias meeting of sedimentology, opatija, field trip guidebook, 155–161. raeymaekers, g. (2000): conserving mires in the european union. actions co-financed by life-nature. ecosystems ltd, luxembourg. roden, e.e. & edmonds, j.w. (1997): phosphate mobilization in iron-rich anaerobic sediments: microbial fe(iii) oxide reduction versus iron-sulfide formation.– arch. hydrobiol., 139, 347–378. royden, l.h. (1988): late cenozoic tectonics of the pannonian basin system.– in: royden, l.h. & horvath, i.f. (eds.): the pannonian basin. a study in basin evolution (aapg memoir, tulsa, 45, 27–48. royden, l.h., horvath, f., nagymarosy, a. & stegena, l. (1983): evolution of the pannonian basin system 2, subsidence and thermal history.– tectonics, 2, 91–137. doi: 10.1029/tc002i001p00091 rothe, m., frederichs, t., eder, m., kleeberg, a. & hupfer, m. (2014): evidence for vivianite formation and its contribution to long-term phosphorus retention in a recent lake sediment: a novel analytical approach.– biogeoscience, 11, 5169–5180. doi:10.5194/bg-11-5169-2014. rothe, m., kleeberg, a., grüneberg, b., friese, k., pérez-mayo, m. & hupfer, m. (2015): sedimentary sulphur: ratio indicates vivianite occurrence: a study from two contrasting freshwater systems.– plos one, 1–18. doi: 10.1371/ jurnal.phone.0143737. rothe, m., kleeberg, a. & hupfer, m. (2016): the occurence, identification and environmental relevance of vivianite in waterlogged soils and aquatic sediments.– earth-science reviews, 158, 51–64. doi: 10.1016/j.erscirev.2016.04.008. šegota, t. & filipčić, a. (2003): köppenova podjela klima i hrvatsko nazivlje.– geoadria, 8/1, 17–37. šercelj, a. (1979): pregled pleistocenske flore jugoslavije.– in: benac, a. (ed.): praistorija jugoslavenskih zemalja, sv. 1: paleolit i mezolit [prehistory of yugoslav countries/paleolithic and mesolithic – in croatian].– akademija nauka i umjetnosti bosne i hercegovine, sarajevo, 35–53. šikić, k., basch, o. & šimunić, an. (1977): osnovna geološka karta sfrj 1:100.000. list zagreb, l 33-80 [basic geological map of sfry, 1:100000. zagreb sheet – in croatian].– institut za geološka istraživanja zagreb, savezni geološki zavod beograd. šikić, k., basch, o. & šimunić, an. (1979): osnovna geološka karta sfrj 1:100.000. tumač za list zagreb [basic geological map of sfry, 1:100000, geology of the zagreb sheet – in croatian].– institut za geološka istraživanja zagreb, savezni geološki zavod beograd, 81 p. šikić, k. (1995): prikaz geološke građe medvednice. [review of structure of the medvednica mt. – in croatian].– in: šikić, k. (ed.): geološki vodič medvednice. institut za geološka istraživanja, ina industrija nafte d.d., zagreb, 5–30. šimunić, a. & basch, o. (1975): stratigrafija kvartarnih sedimenata zagrebačkog posavlja [stratigraphy of quaternary sediments of zagreb posavlje – in croatian].– geol. vjesnik, 28, 153–164. šimunić, a., novosel-škorić, s. & piljurović, lj. (1988): litološka korelacija i kronostratigrafsko razgraničavanje kvartarnih naslaga na lokalitetu prevlaka jugoistočno od zagreba. [chronostratigraphic subdivision of quaternaty sediments from the location prevlaka southern from zagreb – in croatian, english summary].– geološki vjesnik, 41, 167–179. slovenec, d. & lugović, b. (2008): amphibole gabbroic rocks from the mt. medvednica ophiolite mélange (nw croatia): geochemistry and tectonic setting.– geologica carpathica, 59/4; 277–293. slovenec, d. & lugović, b. (2009): geochemistry and tectono-magmatic affinity of mafic extrusive and dyke rocks from the ophiolite melange in the sw zagorje-mid-transdanubian zone (mt. medvednica, croatia).– ofioliti 34/1, 63–80. slovenec, d. & lugović, b. (2012): evidence of the spreading culmination in the eastern tethyan repno oceanic domain assessed by the petrology and geochemistry of n-morb extrusive rocks from the mt. medvednica ophiolite mélange (nw croatia).– geologia croatica, 65/3, 435–446. doi: 10.4154/gc.2012.32 tomljenović, b., csontos, l. márton, e. & márton, p. (2008): tectonic evolution of the northwestern internal dinarides as constrained by structures and rotation of medvednica mountains, north croatia, geol.– soc. london, spec. publ., 298/1, 145–167. transeau, e.n. (1926): the genus mougeotia.– the ohio journal of science, v.26, n.6, 311–338. trefethen, j.m. (1950): classification of sediments.– am. j. sci., 248, 55–62. turner, m.a., robinson, g.g.c., townsend, b.e., hann, b.j., amaral, j.a. (1995): „ecological effects of blooms of filamentous green algae in the littoral zone of an acid lake“.– canadian journal of fisheries and aquatic sciences, 52, 2264–2275. van geel, b. (1976): fossil spores of zygnemataceae in ditches of a prehistoric settlement in hoogkarspel (the netherlands).– rev. palaeobot. palynol., 22, 337–344. van geel, b. (1978): a palaeoecological study of holocene peat bog sections in germany and the netherlands, based on the analysis of pollen, spores and macroand microscopic remains of fungi, algae, cormophytes and animals.– rev. palaeobot. palynol., 25, 1–120. doi: 10.1016/0034-6667(78)90040-4 van geel, b., coope, g.r. & van der hammen, t. (1989): palaeoecology and stratigraphy of the lateglacial type section at usselo (the netherlands).– rev. palaeobot. palynol., 60, 25–129. doi: 10.1016/0034-6667(89)90072-9 velić, j. & durn, g. (1993): alternating lacustrine-marsh sedimentation and subaerial exposure phases during quaternary: prečo, zagreb, croatia.– geologia croatica, 46/1, 71–90. doi: 10.4154/gc.1993.06 velić, j., tadej, n., durn, g. & saftić, b.(1995): genesis of quaternary deposits in the area of zagreb and surroundings of samobor.– in: vlahović, i., velić, i. & šparica, m. (eds.): first croatian geological congress, opatija, abstracts, p. 97. velić, j., saftić, b. & malvić, t. (1999): lithological composition and stratigraphy of quaternary sediments in the area of the „jakuševec“ waste depository (zagreb, northern croatia).– geologia croatica, 52/2, 119–130. doi: 10.4154/ gc.1999.10 vrsaljko, d. (1999): the pannonian paleoecology and biostratigraphy of mollusca from kostanjek-medvednica mt.croatia.– geologia croatica, 52/1, 9–27. doi: 10.4154/gc.1999.02 vrsaljko, d., pavelić, d., miknić, m., brkić, m., kovačić, m., hećimović, i., hajek-taddese, v., avanić, r., kurtanjek, k. (2006): middle miocene (upper badenian/sarmatian) paleoecology and evolution of the environments in the area of medvednica mt. (north croatia).– geologia croatica, 59/1, 51–63. doi: 10.4154/gc.2006.04 worobiec, e. (2014): fossil zygospores of zygnemataceae and other microremains of freshwater algae from two miocene palaeosinkholes in the opole region, sw poland.– acta palaeobotanica, 54/1,113–157. doi: 10.2478/acpa-2014-0005 2018 | 71/3 | 147 – 162 | 12 figs. | 2 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction karst polje are extremely important geomorphological features not only in a cultural sense (pilaar birch & vander linden, 2018), but also as a geological phenomenon. polje is the internationally accepted slavic word for karst polje, described and classified by ford & williams (2007, p.361-365). poljes, are small to large flat areas in rough karstic terrain, are usually places of sediment accumulation, which may well be the only fertile areas for agriculture in the district (romić et al., 2014). in many cases in the recent past, the poljes were seasonally flooded and temporary lacustrine environments were established (ford & williams, 2007). lakes in karstic areas and their sediment accumulations can provide an exclusive record of changes in a local and global environment. an excellent example is the vrgoračko polje with its water originating from estavelles (= reversing springs that can temporarily function as ponors) (ford & williams, 2007). ponor is another internationally accepted slavic word for swallow hole (ford & williams, 2007, p. 118). the estavelles are mostly situated along the north-western edge of the vrgoračko polje. during the autumn, heavy seasonal rainfall, especially in the hypsometrically higher poljes of the dalmatinska zagora, causes activation of the estavelles, resulting in flooding of the polje. such a seasonal fluctuation of the water level and alternation between lake and dry polje is a well-known phenomenon and quaternary depositional environments in the vrgoračko polje/ lake (se croatia) †hrvoje posilović1, lidija galović1, petar stejić2, mihajlo pandurov2 and rodoljub gajić2 1 croatian geological survey, sachsova 2, zagreb, croatia (lgalovic@hgi-cgs.hr) 2 geological survey of serbia, rovinjska 12, beograd, serbia doi: 10.4154/gc.2018.16 abstract the vrgoračko polje is a karst field with a surface area of 37 km2 and an altitude of between 20 and 28 m above sea level, situated at the southern edge of the dalmatian zagora. during the quaternary the polje was flooded for variable periods of time and a lacustrine environment was established. a multidisciplinary study of drill-cores, outcrops and geoelectric measurements recognised five main sedimentary facies: laminated sediment, redeposited sediment, coarsegrained carbonate debris, littoral clay and lacustrine chalk. based on the facies analysis, depositional environments developed during the holocene include aquatic lacustrine littoral and deeper-water environments. the terrestrial environment is represented by a desiccated lake phase. the littoral clay facies (filling depressions and caverns in the karst relief) is laterally equivalent to the deep-water laminated facies (varves?). a stratigraphic break between littoral clay and lacustrine chalk could be time-equivalent to disturbed laminated sediments deposited in deeper-water and to local intercalations of coarse-grained carbonate debris in shallow-water facies sediments. these features could have been the result of a neotectonic event (earthquake), which triggered debris flows of colluvial material from slopes around the lake, and this could also have changed the hydrological regime of the vrgoračko polje and affected subsequent depositional facies. according to 14c dating, deposition of the lacustrine chalk started at the beginning of the mid-holocene warm period (7686±36 abp) with a sedimentation rate of approximately 0.51 mm a-1 during the middle, and 0.58 mm a-1 during the late holocene to today. calculated carbonate production was estimated at 1050 gm-2 a-1. a temporary phase of subaerial exposure of the lake is indicated by desiccation cracks and two bioturbated palaeosol horizons. the described depositional environments and sediment facies found in the vrgoračko polje could be considered to represent a typical quaternary lacustrine sedimentation pattern for other dinaric karst poljes. described in the cerkničko polje, slovenian dinaric karst (valvasor, 1689; pleničar, 1954; smrekar, 2000). similarly, in the karstic lake banyoles (ne spain), morellón et al. (2014) reported intense groundwater inflow that leads to the fluidization and re-suspension of previously deposited sediments. seasonal autumn flooding of the vrgoračko polje may (re)establish a lacustrine environment that lasts through the winter as confirmed by zonal vegetation around the polje (fig. 1). likewise, seasonal runoff through estavelles and ponors into the neretva river (e of the vrgoračko polje), and the artificial prigon tunnel draining into the baćinska lakes (s of the vrgoračko polje), leave the vrgoračko polje dry throughout the summer. the matica river is the only permanent stream that meanders from its springs in the nw, splits to the south and the east and then sinks (fig. 1). the altitude difference between the springs, estavelles and ponors is approximately 8 metres. the process of seasonal alternation of lacustrine and terrestrial environments is repeated annually. however, historically, the vrgoračko polje used to be flooded all year round, with seasonal water-level fluctuation (personal communication from residents). likewise, temporary desiccation of the vrgoračko polje could have lasted for years and centuries. in the south-eastern part of the vrgoračko polje, a medieval cemetery is located with monumental tombstones known as stećci a valuable cultural heritage originating from the middle ages (n=43°06’53’’; e=17°26’40’’ at an altitude of about 35 m above sea level) (tomasović et al., 2008). it can be assumed that the article history: manuscript received december 09, 2016 revised manuscript accepted september 06, 2018 available online october 12, 2018 keywords: karst polje, lacustrine facies, lake sediment, quaternary, vrgoračko polje, croatia g eo lo gi a c ro at ic a geologia croatica 71/3148 inhabitants would not have located a cemetery where there is a high chance of flooding. the aim of this paper is to describe and interpret the lacustrine sediments of the vrgoračko polje, with a special focus on erosion and resedimentation of the lake sediments as a consequence of water runoff. the facies and depositional environments described here provide a basis for future more detailed research and comparisons with other quaternary lacustrine sediments from elsewhere in the dinaric karst. 2. geological setting the investigated area is located in the dalmatian zagora region ne of the biokovo mountain in se croatia (fig. 2). the orientation of the main tectonic structures is nw-se (the dinaric strike) (herak, 1986, 1991). neotectonic movements are still active in the region (cvijanović et al., 1981; božičević & benček, 1983; herak et al., 1995, 1996; blašković, 1998; dragičević et al., 1999; vlahović et al., 2007). the vrgoračko polje is located at the southern edge of the dalmatian zagora with an elongation along the dinaric trend, enclosing an area of 37 km2; the elevation drops to the se from an altitude of 28 to 20 m above sea level. the vrgoračko polje is mostly formed on upper cretaceous limestones and to a smaller extent on palaeocene to eocene limestone and eocene flysch (marinčić et al., 1972; magaš et al., 1972) (fig. 3). structurally, the area is developed on faults and overturned anticlinal structures with cretaceous limestones thrust on to the eocene flysch, so this area could be regarded as a structural polje (ford & williams, 2007, p. 363-364). in an earlier study, two main depositional units within the vrgoračko polje were described: lacustrine chalk and pleistocene clay (magaš et al., 1972). these terms are retained here and discussed in a later section. on the basis of the molluscan fauna and pollen analysis, the authors dated the lacustrine section as holocene, with sedimentation beginning in the late pleistocene. 3. methods 3.1. field methods field investigation and sampling were carried out during the summer of 2015 and spring of 2016 and 118 sediment samples were collected from drill-cores and outcrops (fig. 3). specifically, samples were collected from the plina (48) and umčani (30) trenches, from plina i (4) and špila (7) outcrops and from five drill-cores (29=6+6+4+3+10) (table 1). additionally, eight samples from drill-cores (v1 (3), v2 (1), v3 (3), v4 (1)) were collected for a study of their sedimentological and post-depositional features (micromorphological analysis). at five locations along the ne edge of the vrgoračko polje, five to eight metre long, 12 cm diameter cores were drilled. sampling intervals were defined based on colour, composition, sedimentological characteristics and the presence of fossils. if a lithological unit was thicker than one metre, at least one sample was collected per metre. four sections were investigated in detail (plina, umčani, plina i and špila) (fig. 3). after removing the uppermost 20 cm (modern soil), horizons were defined on the basis of colour, lithological characteristics (composition, structure and texture) and the presence of fossils. the lateral extent of horizons and contacts in vertical sections were described in order to reconstruct sedimentation-erosional processes and rates. samples weighing about 3 kg were taken at 10 cm intervals in the plina (fig. 4) and the umčani sections. in the plina i and špila outcrops one sample was collected for each recognized horizon. contacts between layers were described and sampled for micromorphological analysis. colours of the samples were determined on wet sediment by reference to the munsell soil colour charts (munsell soil color book, 2013). grain size, roundness, grading and sorting of coarse-grained sediments were visually estimated based on analysis of approximately 30 grains. figure 1. panorama of the plina area with detail of one of the branches of the matica river and one of the estavelles (june). inset: erosional area around estavelles with desiccation cracks (april). g eologia c roatica posilović et al.: quaternary depositional environments in the vrgoračko polje/lake (se croatia) 149 figure 2. location map of the vrgoračko polje. figure 3. geological map of the vrgoračko polje area (marinčić et al., 1972) with the locations of investigated drill-cores (v1-v5), outcrops (plina, umčani, plina i and špila) and geoelectrical sounding profiles ( s1-s6 and s21-s24). g eo lo gi a c ro at ic a geologia croatica 71/3150 3.2. laboratory methods complete preparation of samples and their analysis were undertaken in the croatian geological survey, except for 14c dating performed by the radiocarbon dating service directams, usa. samples from outcrops (89) and drill-cores (29) were air-dried for approximately one month in order to preserve micromorphological features. after drying, 8 intervals of core were selected for micromorphological observations. 3.2.1. micromorphological observations studies of polished samples focused on the transitional layer between clay, silt and lacustrine chalk in order to determine composition, soft-sediment deformation (ssd), a source of the sediment and depositional mechanism. to avoid disturbance by drilling, the inner parts of the cores were selected for micromorphological observations. for that purpose dry core was meridionally sawn and the inner flat side was polished, lacquered and scanned. table 1. list of samples, depths of sampling and colours of analysed horizons according to the munsell soil colour book (2013). sample hight above the bedrock or the bottom of the core (m) munsell colour (2013) sample depth from bedrock (m) munsell colour (2013) sample hight above the bedrock (m) munsell colour (2013) drilling cores trench plina n 43.16993°, e 17.38892° trench umčani n 43.16993°, e 17.38892° vrg 1 n 43.174°, e 17.412° vj 1 0.0 0.1 7.5 yr 4/4 brown vu 1 0.0 0.1 7.5 yr 3/3 dark brown 1/1 3.4-4.6 10 yr 5/6 yellowish brown vj 2 0.1 0.2 7.5 yr 4/4 brown vu 2 0.1 0.2 7.5 yr 3/3 dark brown 1/2 3.2-3.4 10 yr 5/6 yellowish brown vj 3 0.2 0.3 7.5 yr 4/4 brown vu 3 0.2 0.3 7.5 yr 3/3 dark brown 1/3 2.0-3.2 7.5 yr 4/4 brown vj 4 0.3 0.4 7.5 yr 4/4 brown vu 4 0.3 0.4 7.5 yr 3/3 dark brown 1/4 1.8-2.0 10 yr 4/4 dark yellowish brown vj 5 0.4 0.5 7.5 yr 4/4 brown vu 5 0.4 0.5 7.5 yr 3/3 dark brown 1/5 1.0-1.8 10 yr 4/4 dark yellowish brown vj 6 0.5 0.6 7.5 yr 4/4 brown vu 6 0.5 0.6 7.5 yr 3/3 dark brown 1/6 0.0-1.0 10 yr 4/4 dark yellowish brown vj 7 0.6 0.7 7.5 yr 4/4 brown vu 7 0.6 0.7 7.5 yr 3/3 dark brown vrg 2 n 43.172°, e 17.418° vj 8 0.7 0.8 7.5 yr 4/4 brown vu 8 0.7 0.8 7.5 yr 3/3 dark brown 2/1a 3.80-4.80 10 yr 6/4 light yellowish brown vj 9 0.8 0.9 7.5 yr 4/4 brown vu 9 0.8 0.9 7.5 yr 3/3 dark brown 2/1b 2.80-3.80 10 yr 6/4 light yellowish brown vj 10 0.9 1.0 10 yr 5/4 yellowish brown vu 10 0.9 1.0 7.5 yr 3/3 dark brown 2/1c 1.80-2.80 10 yr 6/4 light yellowish brown vj 11 1.0 1.1 2.5 y 7/3 pale brown vu 11 1.0 1.1 7.5 yr 3/3 dark brown 2/2 1.50-1.80 10 yr 4/4 dark yellowish brown vj 12 1.1 1.2 2.5 y 7/3 pale brown vu 12 1.1 1.2 7.5 yr 3/4 dark brown 2/3 1.25-1.50 10 yr 4/3 brown vj 13 1.2 1.3 2.5 y 7/3 pale brown vu 13 1.2 1.3 7.5 yr 3/4 dark brown 2/4 0.00-1.25 10 yr 4/4 dark yellowish brown vj 14 1.3 1.4 2.5 y 7/3 pale brown vu 14 1.3 1.4 7.5 yr 3/4 dark brown vrg 3 n 43.158°, e 17.389° vj 15 1.4 1.5 2.5 y 7/4 pale brown vu 15 1.4 1.5 7.5 yr 3/4 dark brown 3/1 2.20-4.80 10 yr 6/3 pale brown vj 16 1.5 1.6 2.5 y 7/4 pale brown vu 16 1.5 1.6 7.5 yr 3/4 dark brown 3/2 1.65-2.20 10 yr 4/4 dark yellowish brown vj 17 1.6 1.7 2.5 y 7/4 pale brown vu 17 1.6 1.7 7.5 yr 3/4 dark brown 3/3 1.20-1.65 10 yr 4/4 dark yellowish brown vj 18 1.7 1.8 2.5 y 7/4 pale brown vu 18 1.7 1.8 7.5 yr 3/4 dark brown 3/4 0.00-1.20 7.5 yr 4/4 brown vj 19 1.8 1.9 2.5 y 6/4 light yellowish brown vu 19 1.8 1.9 7.5 yr 4/4 brown vrg 4 n 43.132°, e 17.447° vj 20 1.9 2.0 2.5 y 6/4 light yellowish brown vu 20 1.9 2.0 7.5 yr 4/4 brown 4/1 2.20-5.70 2.5 y 7/3 pale brown vj 21 2.0 2.1 2.5 y 6/4 light yellowish brown vu 21 2.0 2.1 7.5 yr 5/4 brown 4/2 1.15-2.20 10 yr 5/4 yellowish brown vj 22 2.1 2.2 2.5 y 6/4 light yellowish brown vu 22 2.1 2.2 10 yr 5/4 yellowish brown 4/3 0.00-1.15 7.5 yr 4/4 brown vj 23 2.2 2.3 2.5 y 6/3 light yellowish brown vu 23 2.2 2.3 10 yr 5/4 yellowish brown vrg 5 n 43.125°, e 17.473° vj 24 2.3 2.4 2.5 y 7/3 pale brown vu 24 2.3 2.4 10 yr 5/4 yellowish brown 5/1a 7.0-7.8 10 yr 6/4 light yellowish brown vj 25 2.4 2.5 2.5 y 7/3 pale brown vu 25 2.4 2.5 10 yr 5/4 yellowish brown 5/1 b 6.0-7.0 10 yr 6/4 light yellowish brown vj 26 2.5 2.6 2.5 y 7/3 pale brown vu 26 2.5 2.6 10 yr 5/4 yellowish brown 5/1c 5.0-6.0 10 yr 6/4 light yellowish brown vj 27 2.6 2.7 2.5 y 7/4 pale brown vu 27 2.6 2.7 10 yr 5/4 yellowish brown 5/1d 4.0-5.0 10 yr 6/4 light yellowish brown vj 28 2.7 2.8 2.5 y 6/4 light yellowish brown vu 28 2.7 2.8 10 yr 5/4 yellowish brown 5/1e 3.0-4.0 10 yr 7/4 very pale brown vj 29 2.8 2.9 2.5 y 6/3 light yellowish brown vu 29 2.8 2.9 10 yr 5/4 yellowish brown 5/1f 2.0-3.0 10 yr 7/4 very pale brown vj 30 2.9 3.0 2.5 y 6/2 light brownish gray vu 30 2.9 3.0 10 yr 5/3 brown 5/1g 1.5-2.0 10 yr 7/4 very pale brown vj 31 3.0 3.1 2.5 y 6/2 light brownish gray 5/1h 1.0-1.5 10 yr 7/4 very pale brown vj 32 3.1 3.2 2.5 y 6/2 light brownish gray 5/1i 0.2-1.0 10 yr 7/4 very pale brown vj 33 3.2 3.3 2.5 y 6/2 light brownish gray 5/2 0.0-0.2 10 yr 4/6 dark yellowish brown vj 34 3.3 3.4 2.5 y 7/2 light gray vj 35 3.4 3.5 2.5 y 7/2 light gray outcrop plina i n 43.110°, e 17.455° vj 36 3.5 3.6 2.5 y 7/2 light gray vk 1 1.25-1.50 10 yr 4/3 brown vj 37 3.6 3.7 2.5 y 7/2 light gray vk 2 1.05-1.25 2.5 y 7/2 light gray vj 38 3.7 3.8 2.5 y 7/2 light gray vk 3 0.65-1.05 2.5 y 7/2 light gray vj 39 3.8 3.9 2.5 y 7/2 light gray vk 4 0.00-0.65 2.5 y 7/2 light gray vj 40 3.9 4.0 2.5 y 7/2 light gray vj 41 4.0 4.1 2.5 y 7/2 light gray outcrop špila n 43.11255°, e 17.46620° vj 42 4.1 4.2 2.5 y 6/2 light brownish gray vrg 2 2.1-3.7 2.5 y 7/3 pale brown vj 43 4.2 4.3 2.5 y 6/2 light brownish gray vrg 3 1.8-2.1 10 yr 6/6 brownish yellow vj 44 4.3 4.4 10 yr 6/2 light brownish gray vrg 4 1.4-1.8 10 yr 4/4 dark yellowish brown vj 45 4.4 4.5 10 yr 5/3 brown vrg 6 0.9-1.4 7.5 yr 4/4 brown vj 46 4.5 4.6 10 yr 5/3 brown vrg 7 0.4-0.9 5 yr 4/4 reddish brown vj 47 4.6 4.7 10 yr 5/3 brown vrg 8 0.0-0.4 10 yr 7/3 very pale brown vj 48 4.7 4.8 10 yr 4/3 brown g eologia c roatica posilović et al.: quaternary depositional environments in the vrgoračko polje/lake (se croatia) 151 3.2.2. composition of the lacustrine chalk the content of siliciclastic detritus was calculated after dissolving the carbonate from 0.5 kg of dry sediment (5% hcl). after micromorphological observation of the lacustrine chalk and visual estimation of the percentage of bioclastic material, 1 kg of dry sediment was soaked in water, sieved (2 mm, 1 mm, 0.466 mm, 0.263 mm) and all fractions were dried (105°c). fossils larger than 2 mm were separated by naked-eye observation, and smaller fractions were analysed under a microscope. the diversity of bioclastic material is reported as wt%. 3.2.3. radiocarbon dating (14c) the age of the sediments was determined by radiocarbon dating (ams method) of gastropod opercula. bithynia tentaculata opercula are composed of calcite and were well preserved in the lacustrine chalk without any sign of recrystallization. three samples of opercula were separated from the bottom, middle and top of the lacustrine chalk from the plina section (samples vj 10, vj 15 and vj 41) (figs. 4 & 6). the opercula from the clay underlying the lacustrine chalk were recrystallized and considered unsuitable for dating. the ages are expressed in years before present (abp) where “present” is defined as ad 1950 (currie, 2004). 3.2.4. geophysical survey a geophysical survey was carried out by specific electrical resistivity – geoelectric sounding. it was performed using the schlumberger symmetrical array of current and potential electrodes with an electric range ab/2 up to 200 m. measurements were made using a transistor compensation instrument (tk-24) on profiles in the central part of the vrgoračko polje (fig. 3). quantitative interpretation of field measured diagrams of geoelectric sounding was based on a determination of the value of the electrical resistivity and thickness of the registered geoelectric units. interpretation of measured diagrams of the geoelectric sounding album was performed using a twoand three-layer theoretical diagram. the parameters determined by the method of geoelectric sounding were: the specific electrical resistance (ρ), thickness (h) and depth (d) for each geophysical unit. 4. results 4.1. description of the analysed drill-cores and sections the coordinates and results of the analyses of samples from the drill-cores and four sections are shown in table 1 and figures 5 and 6. the sedimentological characteristics are based on visual inspection in the field. 4.1.1. laminated sediments laminated sediments occur in the lower parts of drill-cores v1v5 located along the ne edge of the vrgoračko polje. they are composed of alternating sub-millimetre clayey dark (7.5 yr 4/4– brown (munsell soil color book, 2013)) coloured and light (10 yr 6/4–light yellowish brown (munsell soil color book, 2013)) coloured laminae (fig. 5). light coloured laminae contain yellowish to brownish and black iron and manganese oxide impregnations and micro-concretions. in some light laminae with millimetre and sub-millimetre limestone fragments and gastropod opercula (bithynia tentaculata), the regularity and rhythmicity of lamination are disturbed and deformed. there is no visible preserved plant material. compositional colour is determined as dark yellowish brown and brown (table 1). the base of the laminated layer was not reached. thus the total thickness of laminated sediments is not known and, therefore, a laminae count would have been pointless. the lamination is disturbed by ssd (fig. 7a) in all samples, and additional disturbance by drilling was avoided in the analysed samples. graded bedding within laminae and erosional boundaries within laminated sediments were not recognized. based on field observations, it is the fine sediment, homogenous in appearance, except for up to 5% silt and sand-sized limestone fragments, gastropod opercula and early diagenetic impregnations and micro-concretions (fig. 7a). there is a sharp irregular contact of the laminated sediments with overlying disturbed clayey and carbonate sediment. some waterescape structures could be related to cracks in the sample, and brownish to black iron and manganese oxide impregnations have been precipitated in some of them (e.g. fig. 7a). 4.1.2. disturbed clayey and carbonate sediments these sediments were found in drill-cores v1-v5 (figs. 3 & 5) above the laminated sediments. they are composed of carbonate intercalations in clay sediment and clay intercalations in lacustrine chalk (fig. 7). alternations between these two types of deposit are marked by erosional borders (fig. 7 (e)). in this colourful section, lacustrine chalk is light yellowish brown or yellowish brown (10 yr 6/4 – 5/4), and the colour of the clay ranges from brown (7.5 yr 4/4 and 10 yr 4/3) to dark yellowish brown (10 yr 4/4) (munsell soil color book, 2013) (table 1). numerous sub-angular limestone fragments, up to 2 cm in diameter are present, mostly with a corroded surface impregfigure 4. trench of the plina section. g eo lo gi a c ro at ic a geologia croatica 71/3152 nated by surrounding clay sediments, giving them an orange margin. however, the interior of all carbonate clasts is greyish and contains dense black spots of fe-mn oxides (fig. 7b (f)). the matrix is clay with abundant feand/or mn-nodules 3-5 mm in diameter. clayey clasts are composed of laminated sediment (see section 4.1.1.) within a chalk matrix. they are rounded and plastically deformed with preserved laminae (fig. 7b (c)). lamination inside the clasts is curved and folded, following the clast outlines. gastropod opercula (bithynia tentaculata) occur in the clayey clasts and in the silty matrix. they are well preserved, two to six mm long, and are imbricated following sedimentary sorting (boggs, 2013). silty lacustrine chalk contains feand/or mnnodules similar to those in the clayey matrix, but they are approximately 10 times less common (fig. 7b). 4.1.3. coarse-grained sediments coarse-grained sediments occur in the south-eastern marginal area of the vrgoračko polje and are described in the špila profile (figs. 3 & 6). in view of the disturbed nature of these sediments, it was not possible to estimate their lateral extent and geometry. colour varies significantly (dark yellowish, yellowish, reddish brown and brown), depending on the red clay content in the matrix (table 1). clasts are fragments of cretaceous limestone. four sediment types are present: very poorly sorted, clast-supported breccia with angular fragments. cretaceous limestone clasts range in size from 5 to 70 mm, and the matrix is a fine-grained, light-coloured carbonate with high porosity. the matrix is composed of friable skeletal debris and thus determined as lacustrine chalk. the bed thickness is approximately 70 cm, and laterally it passes into a breccia-conglomerate, retaining the same thickness. breccia-conglomerate, clast-supported with poor to moderate sorting of clasts. in some cases, inverse grading is followed by normal grading. roundness of clasts ranges from angular to sub-rounded and size ranges from 5 60 mm. interstices between cretaceous limestone fragments are filled with lacustrine chalk, and terrestrial gastropod shells are also present. clast-supported well-sorted conglomerate was observed in several loose blocks (dimensions approximately 2 x 1 x 1.5 m). two or three beds of conglomerate were recognized in each block, and they are 10 40 cm thick. clasts are 5 to 50 mm in size and well-rounded. cretaceous limestone clasts are imbricated parallel to the bedding plane (approximately e-w). sorting increases with the clast roundness. matrix-supported, unsorted, angular to sub-angular pebbles, cobbles and boulders are intercalated in clay or lacustrine chalk (fig. 6). the long axes of the clasts are inclined to the bedding plane. this sediment body has a channel form that is only partially preserved. the channel form in the outcrop is about 20 m wide and 1.5 m thick, and is incised into the underlying clay with a strong erosional boundary (fig. 6). the clasts are ab-plane imbricated, where the intermediate clast axes are oriented in the flow direction and the longest axes are perpendicular to the flow to the se (approximately 300/20). 4.1.4. clay clay found in the lowest parts of the plina, umčani and špila profiles (fig. 6), overlies cretaceous limestone, filling depressions and caverns in the karst relief, outcropping in ravines in the northern, western and southern sides of the polje. in the eastern part figure 5. lithology and carbonate content of boreholes v1-v5. for the location of boreholes see figure 2. g eologia c roatica posilović et al.: quaternary depositional environments in the vrgoračko polje/lake (se croatia) 153 figure 6. lithology, age, and carbonate content of sections plina, umčani, plina i and špila illustrated by photographs of interesting details. the legend is the same as for figure 4. for the location of the sections see figure 2. of the polje the clay was recognized in drill-cores as sediment that overlies the deep-water laminated or the disturbed sediments (fig. 5). the clay was studied in the sections, because it was more reliable than investigation of its sedimentological characteristics in drill-cores. the clays are structureless and intensively bioturbated, containing numerous opercula of bithynia tentaculata and fragments of cretaceous limestone (fig. 7b). in some horizons, especially the lower part of the umčani section (fig. 6), numerg eo lo gi a c ro at ic a geologia croatica 71/3154 figure 7. a) irregular contact of the laminated sediments (lower part of the photo) and disturbed clayey and carbonate sediments (upper part of the photo). b) the erosional boundary between sediments redeposited in a deeper lacustrine facies and littoral clays (e), cretaceous limestone fragments that originate from surrounding slopes within littoral clays (f ), the convolution of lamina (c), waterescape structure (v), the redeposited material of lacustrine chalk (k). ous iron and manganese concretions occur. limestone fragments (if present) are mainly corroded and recrystallized, with iron and manganese oxides precipitated on their surface. in the case of recrystallized limestone fragments, fe and mn oxides are also found inside the fragments, filling and coating pores and fissures. there is a sharp transition between the clay and the lacustrine chalk with increasing carbonate content (fig. 4). the boundary is intensively bioturbated and burrows are filled with overlying lacustrine chalk and vice versa (fig. 6). likewise, the overlying sediment fills polygonal desiccation cracks in the clay (figs. 6 & 8). 4.1.5. lacustrine chalk considering superposition, the lacustrine chalk is the youngest and the most widespread sediment in the vrgoračko polje (fig. 3). it occurs in all the upper parts of sections and investigated drill-cores. the chalk overlies the cretaceous limestone in the plina i section; the clay in the plina and umčani sections; coarsegrained matrix-supported clasts in the špila section (fig. 6); and disturbed clayey and carbonate sediments such as those found in drill-cores v1-v5 (fig. 5). at the plina and umčani sections, the chalk has been deposited on top of the clay with an erosional and angular unconformity (figs. 3, 4 & 6). the chalk is composed almost completely of characean remains, i.e. characean thalli (tubes up to 3 mm in length) (fig. 9). biogenic carbonate material represents up to 97% of the sediment (fig. 6), and is composed of approximately 80% of authigenic characean carbonate; 15% gastropod opercula, gastropod and ostracod debris, and the remainder comprises the siliciclastic clay fraction. rarely, characean gyrogonites can be found, up to 30 psc. kg-1 of the sample (fig. 9b). a high number of bithynia tentaculata opercula found in littoral clays indicates a high population density. there is no mineral or sediment filling the characean tubes, but calcite overgrowths are rarely developed on some tubes. thalli calcification is very porous (fig. 9a). despite the porosity, there is no visible dissolution or corrosion of carbonate grains. the sediment colour varies from yellowish brown to light grey, depending on the clay and iron content (table 1). 4.2. radiocarbon dating results are presented in units of percent modern carbon (pmc) and the uncalibrated radiocarbon age before present (bp). all results have been corrected for isotopic fractionation with an unreported δ13c value measured on the prepared carbon by the accelerator. a beam of cions was produced by bombarding the surface of a graphite sample with cs+ ions. the cbeam was accelerated, focused and split into 14, 13 and 12 amu beams. raw isotope ratios were transferred to proprietary data analysis software, where final calculations were performed. an aggregate carbon ratio and calculated radiocarbon age are reported and no further correction for fractionation is required (fig. 6 plina, table 2). for analysed samples (vj 10, vj 15 and vj 41) the ages were calculated as 7686±36 abp, 6836±36 abp and 1749±50 abp, respectively. 4.3. geophysical investigation four lithological members were distinguished from the top downwards: unit 1 the natural resistivity is over 25 ohmm; unit 2 the natural resistivity is under 20 ohmm; unit 3 – the natural resistivity is between 50 and 150 ohmm; unit 4 the natural resistivity is over 150 ohmm. the first geophysical unit correg eologia c roatica posilović et al.: quaternary depositional environments in the vrgoračko polje/lake (se croatia) 155 figure 8. desiccation cracks infilled with overlying lacustrine chalk. the white bar is 20 cm. figure 9. a) fossil remains of organisms that composed the lacustrine chalk in the vrgorac polje: debris of characean thalli (ch), gastropod shells (g) and crab nipper (n); b) characean gyrogonites. sponds to the lacustrine chalk; the second unit shows the natural resistivity of clay; the third unit exhibits the geoelectric features of limestone breccia with clay matrix, and the fourth unit corresponds to limestone. figure 10 shows the lithology reconstructed from the geoelectric profiles (leucci, et al., 2004; terzić et al., 2007; romey, et al., 2014; rey et al., 2017). the position of the profiles is shown in figure 3. 5. discussion at present, the vrgoračko polje can be classified as a periodic lake formed within an enclosed internally-drained basin. inflow into such poljes may come from surface streams, springs and estavelles (valvasor, 1689; pleničar, 1954; smrekar, 2000; ford & williams, 2007, p. 118). in the case of the vrgoračko polje, the matica river is a constant surface meandering stream charged by several springs, and in the wet seasons, the lake is inundated by springs and estavelles located along the nw edge of the polje. in apulia, italy, the presence of numerous water supply wells was described in a geologically similar polje setting (leucci et al., 2004). the dry vrgoračko polje can become a lake within a few days (pers. comm. from residents). thus, such a strong inflow of water to the lake could cause resedimentation of the topmost horizon. jarnuszewski & meller (2018) noticed that a change of the environment from limnic to terrestrial, and a decrease in the lake level leads to the formation of characteristic morphological features such as cracks and numerous channels (fig. 1). thus, in the vrgoračko polje, the surface of the polje can be presumed to have been erodable during intensive seasonal inflow. as the water-table level is high during winter, terrestrial slope sediments (colluvial debris and terra rossa) on the surrounding hills become flooded, altering the slope sediments in the littoral environment. as they were immersed in the water, they became lighter and, because of the clay content of terra rossa underlying colluvial debris (durn, 2003; durn et al., 2014), slippery. sliding of slope sediments in winter-time along the littoral environment probably was more dytable 2. results of radiocarbon dating. directams code submitter id hight above the bedrock sample type fraction of modern radiocarbon age pmc submitter id bp 1σ error d-ams 018636 vj10 0.9 1.0 gastropod operculum 38.41 0.17 7686 36 d-ams 018637 vj15 1.4 1.5 gastropod operculum 42.70 0.19 6836 36 d-ams 018638 vj41 4.0 4.1 gastropod operculum 80.43 0.50 1749 50 g eo lo gi a c ro at ic a geologia croatica 71/3156 the terrestrial environment is: c) desiccated lake environment this single facies is documented by the presence of desiccation cracks, erosion surfaces, palaeosols and reworked littoral facies. 5.1. lacustrine deeper-water depositional environment 5.1.1. facies of laminated sediments in the deeper part of the lake, laminated sediments were deposited from suspension as indicated by their grain size (tucker, 2008 p. 253-255). according to geoelectric profiles, the boreholes are located in the part of the vrgoračko polje where the quaternary sediments are the thickest (figs. 3 & 10). the laminated sediments (the second geophysical unit) were only observed there, and results of geoelectrical measurements indicate that the thickness of these, or similar, sediments in the ne area of the polje exceed 60 metres (figs. 3, 5 & 10). the second geophysical unit shows the natural resistivity of clay, and there are no data indicating a possible change in the lithological composition of deeper sediments. accordingly, on the basis of the lithological determination of the deepest samples from drill-cores, it could be presumed that the whole 60 metres of quaternary clays belong to the deep-water laminated facies. ford & williams (2007, p. 276) reported that clays and silts usually accrete as laminae parallel to the depositional surface. there may be a marked fining upwards within a single lamina, which creates a colour change that gives it the appearance of a couplet in many glaciated regions. aggregate sections can total many metres (ford & williams, 2007). with a high degree of certainty, this sediment can be recognised as varves. varve sedimentation reflects seasonal changes in the environment (scheidegger, 1965; o’sulivan, 1983; zolitschka, 2013; zolitschka et al., 2015; trapote et al., 2018; şimşek & çağatay, in press). this facies has an erosional contact with overlying sediments redeposited in the deeper lacustrine facies with a noticeable increased quantity and character of soft-sediment deformation (ssd) (fig. 7). if the erosional contact is related to tectonic events, it could be presumed that ssd in the underlying facies namic than in summer-time on the dry shoreline slope. such gravitational flows (tucker, 2008 p. 82) could be most intensive in the spring-time when the water-level is lowered: littoral sediment is not immersed in the lake water anymore, but it is still wet, heavy and slippery. water outflow through estavelles and ponors into the neretva river and the artificial prigon tunnel into the baćinska lakes would have resulted in erosion of the lake floor, through rapid-flow runoff (ford & williams, 2007, p. 181-182). the investigated sediments indicate environmental variability and dynamics in this karstic field during the holocene. according to reading (1996) and tucker (2008), environment is a complex of physical, chemical and biological conditions (which are not wholly independent) at a given period of time in a given local area. sedimentary facies are bodies of sediment that are recognizably distinct from adjacent sediments that resulted from different depositional environments. however, as a result of studies of holocene sediments, there has been increasing emphasis on the study of the vertical organization of lithologies and structures the lithologic package (pettijohn, 1975; deino et al., 2006; kingston et al., 2007; noble et al., 2015; baker et al., 2018;). the vertical sequence of sedimentary facies is not random but is, instead, organized in a coherent and predictable way. therefore, recognition of the vertical arrangement itself, which places the individual facies and their sedimentary structures in a meaningful sequence or package, enables us to reconstruct a detailed picture of interaction in specific palaeoenvironments (pettijohn, 1975). on the basis of the presented results, two main depositional environments could be identified: aquatic (lacustrine) and terrestrial. in aquatic environments, five sedimentary facies are recognized (fig. 11): a) lacustrine deeper-water depositional environment facies: 1-laminated sediment, 2-redeposited sediment. b) lacustrine littoral depositional environment facies: 1-coarse-grained carbonate debris, 2-littoral clay, 3-lacustrine chalk. figure 10. lithological profiles s1-s6 and s21-s24 reconstructed from the geoelectric resistivity measurements. the legend in figure 11., and the positions of the profiles in figure 2. g eologia c roatica posilović et al.: quaternary depositional environments in the vrgoračko polje/lake (se croatia) 157 were not related to earthquakes, whereas ssd in overlying facies could be related to earthquakes (rudersdorf et al., 2015; lunina & gladkov, 2016; shanmugam, 2017). 5.1.2. facies of sediments redeposited in the deeper lacustrine facies disturbed clayey and carbonate sediments contain plasticallydeformed laminated clasts, lacustrine chalk and clays with limestone fragments (fig. 7). these were presumably carried by water currents or mud flow, and their movement could be the result of slope movement, mud flow and/or rain flash flood (comparable to reports of reineck & singh, 2012). interbedded shallow lacustrine sediments and ssd assigned to palaeoseismic triggering provide strong evidence for the seismic origin of the deformation (rudersdorf et al., 2015). based on the investigation of pleistocene–holocene sediments in the northeastern ejina basin, inner mongolia (a lake environment) (rudersdorf et al., 2015), water-escape structures, folds, convolution, dish structures and small-scale intraformational faults were recognized as earthquake-induced structures (shanmugam, 2017). furthermore, clastic injections in a modern lake in the bajkal region and load casts and convolute lamination from the late pleistocene in the issyk-kul lake, central asia (lunina & gladkov, 2016) are described as a reliable indicator of earthquake-induced structures in modern environments (shanmugam, 2017). alternations of carbonate intercalations in the clay sediments and clay intercalations in the lacustrine chalk sediments were probably deposited by water outflow due to extensive erosion of the clay and lacustrine chalk (fig. 7a). such erosion could be triggered by an earthquake (tucker 2008). based on the geometry of the polje and field observations, general transport directions are from the north west of vrgoračko polje and locally from a shallow to deeper water environment. numerous cretaceous limestone fragments were washed from colluvial sediments on shore, but also from littoral clays. an absence of clay lamination and fining-up structure could lead to the conclusion that they were decanted from a homogeneous suspension that was steadily renewed. littoral clay most probably originates from reworked terra rossa from the drainage basin of the vrgoračko polje. investigation of mineralogy and geochemistry of terra rossa in the dinarides suggests its polygenetic origin (durn, 2003; durn et al., 2014). plastically deformed clasts and curved laminae within the clasts indicate underwater erosion (allen, 1982; van loon & brodzikowski, 1987; avşar et al., 2016; shanmugam, 2017). it could be assumed that mud clasts were ripped up from the shallow lake floor by strong water currents, rounded and deposited in deeper water. in addition, erosional discontinuities between alternating lithologically different layers in the facies indicate sudden environmental change from calm deep-water varved sedimentation to a strong mud flow. this is visible in figure 7b, where laminated clays show ssd structures floating in a lacustrine chalk matrix. clay clasts and lacustrine chalk could have been eroded by strong flow and redeposited over deepwater laminated facies. later, littoral clays with limestone fragments were redeposited on the top of this succession (fig. 7b). 5.2. lacustrine littoral depositional environment 5.2.1. coarse-grained carbonate debris in shallow-water facies the whole perimeter of the vrgoračko polje is defined by strong fault systems (fig. 3) and many of them are neotectonic and still active (cvijanović et al. 1981; božičević & benček, figure 11. reconstruction of the depositional environments in the vrgoračko polje lake. not to scale. g eo lo gi a c ro at ic a geologia croatica 71/3158 1983; herak et al. 1995, 1996; blašković, 1998; dragičević et al. 1999). an especially active zone is located in the se part, where recent colluvial fans have prograded into the polje. the whole facies association (see section 4.1.3. a-c) is the result of slope processes of sliding and sediment-gravity flow movements. very poorly sorted breccia could be colluvial material that prograded into the ancient lake by the mechanism of detrital flow (tucker, 2008 p. 82). wave activity on beaches around the lake margin could round angular clasts of colluvial material to various degrees (fig. 12) and form breccia-conglomerate; alternatively, clasts were subrounded by palaeoflow and then cemented. this could be supported by terrestrial gastropod shells discovered in the matrix. in view of the poorly-graded clasts within the colluvial deposits, it can be assumed that the material was transported quickly by flows in a strong hydrodynamic regime. it is well described as detrital flow (tucker, 2008 p. 82). later, this material could have been reworked by a stream and flash floods and resedimented as alluvium. this presumption is based on the sorting, roundness and imbrication of clasts. it formed the clast-supported well-sorted conglomerate, probably in a fan form. a-axis clast imbrication, with longer clast axis parallel to the stream flow, is typical for a rapidly-decreasing suspension flow (potter & pettijohn, 1977; reineck & singh, 2012), which would have transported material from the lake shore. a different sedimentation process is recorded in the clasts intercalated in clay or lacustrine chalk (see section 4.1.3. d). based on the conspicuous erosional contact with underlying sediments, this sediment body is probably the result of a very dynamic event, which could be described as debris or mud flow. debris or mud flows could have started from colluvial sediments accumulating on top of littoral clays. littoral clays could be the source material for the clayey part of the matrix. colluvium weight and some initiating event (such as rain, the annual lake inundation or earthquake) could result in a debris flow (tucker, 2008 p. 81-82) (as mentioned in the introductory paragraph of the discussion). if the debris was mixed with littoral clay, the material might continue moving as a mud flow (tucker, 2008 p. 82). the flow could incise the channel in the underlying clays and lacustrine chalk. coarse-grained carbonate debris in shallow-water facies (se part of the polje, the špila section) (fig. 6) has an erosional contact with the underlying sediments followed by sedimentation of the overlying lacustrine chalk. in all the other studied sections, lacustrine chalk has an erosional contact with underlying sediment (fig. 6). 5.2.2. littoral clay facies the main feature of littoral clays is that they are structureless and fill depressions and caverns in the karst relief in the shallower part of the palaeolake. ford & williams (2007) call them residual clays. they are massive and thick, generally darker than the sediments redeposited in the deeper lacustrine facies (table 1). however, these clays also contain corroded cretaceous limestone fragments, fe-mn concretions and gastropod opercula. therefore, based on composition, these littoral clays could be the source material for sediments redeposited in the deeper lacustrine facies. their pleistocene age was presumed based on the principle of superposition (magaš et al., 1972). the gastropod opercula were recrystallized and unsuitable for dating. however, although dark, numerous remains of the gastropod bithynia tentaculata and intensive bioturbation indicate an oxic environment with intensive benthic life (bos et al., 2017). there are two possible scenarios for the evolving oxic/anoxic environment: a) periodic deoxygenation and acidification of the littoral environment and b) shallow oxygenation of the pore water in the sediment column during low water-level. it is very likely that both scenarios could occur. during the periods of lower input of oxygenated water, oxygen consumption by living organisms and decaying organic matter can become problematic. as decaying organic matter consumes oxygen it also at the same time increases water acidity (bastviken et al., 2004). the period of dark lamina formation in deep-water laminated clays could correspond to an anoxic acidic period in the littoral environment. figure 12. detail of the modern shore-line around the lake margin during winter. g eologia c roatica posilović et al.: quaternary depositional environments in the vrgoračko polje/lake (se croatia) 159 the gastropod bithynia tentaculata inhabits lakes and ponds with standing or low-velocity water circulation (weeks et al., 2017). this gastropod lives in water up to five metres deep in the littoral zone, grazing on the bottom or on aquatic plants. it is interesting to point out that bithynia can also feed by filtering water, which allows a high population density to survive in eutrophic and shallow water (clarke, 1979; dillon, 2000). sedimentological and archaeological data (the presence of palaeosols and desiccation cracks in the profile and the cemetery in the low part of the polje) indicate that lake water-level periodically decreased and in some parts completely dried up. as it is an invasive gastropod (weeks et al., 2017), an almost monospecific gastropod fauna existed in the lake. 5.2.3. lacustrine chalk facies carbonate deposition in lakes is sensitive to climatic and tectonic influences and dependent upon lake hydrology and morphology. climate controls the rate and nature of biogenic productivity, influences chemical weathering, erosion and runoff rates in the catchment area, and thus determines carbonate supply (platt & wright, 1991). almost the whole area of the vrgoračko polje is covered by chalk sediment and it occurs above all other sedimentary facies. thus, the depositional environment of the lacustrine chalk was the last stage of the lake life cycle (fig. 5). characeae grow in the littoral zone, usually up to 10 or 15 metres water depth (soulie-marsche & garcia, 2015), with a maximum recorded depth of 30 metres (beilby & casanova, 2014). this type of intensive primary carbonate production was confined to the littoral zone, but significant amounts of resedimentation to the deeper-water environment could occur. during the annual rapidflow runoff of lake water (ford & williams, 2007, p. 181-182), fragile characeae thalli could be rinsed and redeposited towards ponors or estavelles. the difference in the floor altitude of the polje is 8 m. at the plina section, there are 3.8 metres of characean carbonate (figs. 1 & 4). the transitional horizon between the littoral clays and lacustrine chalk was erosional and intensively bioturbated, showing an increased carbonate content in the prevailing clayey sediments of the transitional horizon (fig. 5). the lacustrine chalk facies in the vrgoračko polje in the previous study was termed lacustrine chalk (magaš et al., 1972; marinčić et al., 1972). the grain size of lacustrine bioclasts from the vrgoračko polje (up to 3 mm) significantly differs from marine chalk with grains less than 10 micrometres in size (e.g. coccoliths; tucker & wright, 1990) or aragonite mud (sondi & juračić, 2010). jarnuszewski & meller (2018) described holocene lacustrine chalk from nw poland as fine crystalline calcite which, when moistened, forms a type of gel. since the facies in our investigation is dominated by characeae thalli (see section 4.1), in order to avoid any misinterpretation, we could use the term introduced by soulie-marsche et al. (2010) of characeite. the rate of sedimentation: characean algae assimilate co2 from bicarbonate ions during photosynthesis. as a result, calcium carbonate is precipitated on the surface of the thallus (beilby & casanova, 2014, souliemarsche & garcia, 2015). charophytes are extremely successful at calcite precipitation and can be the most important factor in carbonate precipitation in some lakes. pentecost (1984) found that some species of characea can produce annually up to 1100 g of calcium-carbonate per square metre, but the average value of precipitated calcite for different species is more than 400 gm-2 a-1 (pełechaty et al., 2013; apolinarska et al., 2011). based on the 14c dates from three horizons in characean carbonate from the plina section, the average sedimentation rates in the lake can be calculated. the sediment thickness between the oldest date of 7686±36 abp and the intermediate date of 6836±36 abp is 500 mm (fig. 6, table 2). this gives a sedimentation rate of 0.58 mm a-1. between the intermediate and the youngest date, during 5087 years, 2600 mm of characeite were deposited, with a sedimentation rate of 0.51 mm a-1. the similar sedimentation rates could indicate an almost constant rate of characean carbonate production. this small decrease in sedimentation rate could be explained by periodic desiccation of the vrgoračko polje during the late holocene (see section 5.3.) that interrupted carbonate production in a well-balanced lake ecosystem. based on the measured specific mass of the sediment and the sediment volume, carbonate production is estimated to have been 1050 gm-2 a-1. calculated carbonate mass is in the range measured for recent characea by pełechaty et al. (2013) and apolinarska et al. (2011). generally, the sediment is not much altered by diagenesis. water ph in the lake was elevated and probably buffered to a relatively constant value by an excess of easily soluble calcium-carbonate material. 5.3. depositional environment of the periodically desiccated lake in the deepest part of the vrgoračko polje (the plina section) two palaeosols were developed on characeite. thus, it can be presumed that the lake has been at least twice partially desiccated. during desiccation, erosion could become the main sedimentological process in the polje (daura et al., 2017) and the material resedimented into the deeper parts of the basin. characeite is an easily erodible material (fig. 1). in detail, before seasonal or periodic desiccation and water-level fall, the sediment surface remained protected under the cover of aqueous algal remains. during the decay time of the algal remains, the new growth of terrestrial grass could protect the sediment from further erosion (jarnuszewski & meller, 2018). if the top horizon was exposed to strong inflow from the bottom of the lake (springs and estavelles) (ford & williams, 2007; morellón et al., 2014), local streams could remove the protective vegetation cover, and channels could be rapidly formed by erosion. widening and deepening of a channel could be fast. when the channel network was formed, individual channels intersected, merged and separated their flows, as occurs today. the result was indented, irregular relief with steep slopes. at present, in the vrgoračko polje, such erosion takes place in very narrow areas (fig. 1), but erosional processes are very intense since the annual outflow of the water is rapid (pers.comm. from residents). if sediment is exposed above the water-level long enough, pedogenic processes occur. palaeosol intercalations in characeite are brown, intensively bioturbated clays, indicating an abundant in-fauna (retallack, 2001). most of the bioturbation can be attributed to back-filled earthworm burrows (retallack, 2001). pedogenesis is documented in the plina section in samples vj 23 and vj 28-29 (fig. 6). based on interpolation of 14c data and the sedimentation rate, the older palaeosol, could be dated at 5170 abp, and the younger one at 3600 abp. desiccation cracks at the bottom of the characeite in the plina section indicate a temporary phase of subaerial exposure of the lake older than 7686±36 years bp (figs. 6 & 8). occasional lake shallowing and partial desiccation events could also be reflected in the decrease of biogenic carbonate content in the sediment. there are two possible explanations: older g eo lo gi a c ro at ic a geologia croatica 71/3160 clay sediments were eroded and resedimented into the deeper lake zone and/or the production of biogenic (characean) carbonate decreased or stopped. a horizon without bioturbation was recognised in the plina section and is presented in figure 6 (sample vj 31). when the characean carbonate content decreased and the percentage of siliciclastic detrital components increased, numerous bithynia tentaculata opercula would appear. consequently, the development of the bithynia population could indicate an increase in the extent of the shallow littoral zone (johnson et al., 2018), i.e. an increase of bithynia remains in sediment could be an indication of shallowing of the lake. in the plina section, the entire characeite interval is radiocarbon dated to the holocene. the oldest dated sample from the first 10 cm interval of the characeite (7686±36 abp) on the plina section was deposited at the beginning of the mid-holocene warm period (walker et al., 2012). with the climate change during the holocene (walker et al., 2012; surić. & juračić, 2010), environmental conditions could have become favourable for the intensive growth of characean algae. if characean algae, with their mass carbonate production, significantly accelerated lake shallowing (soulie-marsche & garcia, 2015; soulie-marsche et al., 2010), the wider shore areas could have caused more intensive erosion and resedimentation into deeper lake zones. although underlying the disturbed clayey and carbonate sediments, the laminated clay and littoral clays are not dated because the material is unsuitable for dating. however, it could be presumed that they were deposited during the pleistocene and early holocene. the underlying littoral clay at the same location is up to 10 m thick. the sub-millimetre varve structure and sedimentation mechanism of the suspended material indicate a slow rate of sedimentation and consequently a longer time interval for their formation. on the basis of the geophysical profile s 21-24 (fig. 10b) and the plina and umčani sections, the southwestern area of the vrgoračko polje can be characterized as a shallower depositional environment with a slightly inclined wide littoral zone, where littoral clays were deposited (rey et al., 2017). similar to the poljes located in the idria fault system (slovenian dinarides) (pleničar, m., 1954; smrekar, 2000; vrabec, 1994), the hydrological regime and water level of the vrgoračko polje during the holocene could have been changed due to karstification processes and/or neotectonic movements. more intensive neotectonic movements on the ne margin of the vrgoračko polje (cvijanović et al., 1981; božičević & benček, 1983; herak et al., 1995, 1996; blašković, 1998; dragičević et al., 1999) could have caused rapid lake-floor subsidence in that area. in such a deeper-water environment, laminated sediments could accumulate. active neotectonics initiated the formation of colluvial material that was reworked by water and slid into the lake, and today remains as channel fills and alluvial fan facies (lunina & gladkov, 2016; mulder & syvitski, 1995; rudersdorf et al., 2015). vrabec (1994) reported a pull-apart origin for the karst poljes along the idrija strike-slip fault zone (the cerkniško polje). he claimed that neotectonic movements could have caused rapid subsidence that would have undoubtedly produced significant sediment accumulations, at least in the form of marginal talus and debris fans. such movements could have caused more intensive sedimentation and a more diverse vertical sequence of sedimentary facies in the ne rather than in the se part of the vrgoračko polje. 6. conclusions quaternary sediments of the vrgoračko polje represent a record of diverse environments which existed in the area and evolved during the holocene, with the probable beginning of sedimentation during the pleistocene. the whole perimeter of the vrgoračko polje is defined by strong fault systems and many of them are neotectonic and still active. in that periodically inundated polje (lake), three main sediment packages reflect the variability and dynamics of the environment in this polje: deeper-water lacustrine, littoral lacustrine and desiccated lake environments. according to geoelectric profiles, the lacustrine deeper-water deposits could be composed of more than 60 m of varved lake sediments with soft sediment deformation horizons. erosion and local re-sedimentation of underlying sediments with a significant inflow of surrounding slope sediments correspond to tectonic events that could have changed the hydrological regime of the vrgoračko polje and initiated debris and mud flows. these disturbed clayey and carbonate sediments are composed of alternating carbonate intercalations in the clay sediment and clay intercalations in the lacustrine chalk. alternations are marked by erosional contacts. it is assumed that mud clasts were ripped up from the shallow lake floor by strong water currents, rounded and deposited in deeper water. intercalations of clay contain coarser corroded cretaceous limestone fragments. based on the principle of superposition, this set of sediments were redeposited in the deeper lacustrine facies, as reliable earthquake-induced structures, and could be correlated with coarse-grained carbonate debris in shallow-water facies in the littoral depositional environment. the whole facies association (ranging from clast-supported very poorly sorted breccia to well-sorted conglomerate and clasts intercalated in clay or lacustrine chalk) is colluvial material that could prograde into the ancient lake by the mechanism of detrital flow, and could form an erosional contact with underlying sediments. littoral clay filled depressions and caverns in the karst relief in the shallower part of the lake. they are bioturbated and massive, containing corroded cretaceous limestone fragments, fe-mn concretions and gastropod opercula. the lacustrine chalk facies is the most widespread and the youngest sediment in the vrgoračko polje. the chalk (characeite) is composed approximately of 80% authigenic characean carbonate; 15% of gastropod opercula, gastropod and ostracod debris and the rest is siliciclastic detritus. based on 14c analysis, this facies was formed around 7686±36 years bp. a calculated sedimentation rate during the middle holocene is approximately 0.58 mm a-1 and during the late holocene 0.51 mm a-1. similar sedimentation rates could indicate an almost constant rate of characean carbonate production. this small decrease in sedimentation rate could be reflected in the periodic desiccation of the vrgorac lake during the late holocene, documented by the presence of palaeosols and desiccation cracks. based on interpolation of 14c data and sedimentation rate, the older palaeosol could be 5170 abp in age, and the younger one 3600 abp in age. furthermore, a temporary phase of subaerial exposure of the lake, indicated by desiccation cracks, is older than 7686±36 years bp. on the basis of the measured specific mass of the sediment and the sediment volume, the calculated carbonate production is estimated at 1050 gm-2 a-1. acknowledgment this work has been fully supported by the croatian science foundation under the project sapiq 4425. the authors are g eologia c roatica posilović et al.: quaternary depositional environments in the vrgoračko polje/lake (se croatia) 161 very grateful to associated editor, mladen juračić and reviewers maurice tucker, ingeborg soulié-märsche and davor pavelić for providing us with valuable and constructive reviews of our work. we have found lots of useful guidelines in the comments that improved our manuscript. references allen, j.r.l. (1982): sedimentary structures their character and physical basis.– in: allen, j.r.l. (ed.): chapter 9 soft-sediment deformation structures. developments in sedimentology, 30b/ ii.– elsevier, amsterdam, 343–393, 663 p. doi: 10.1016/s0070-4571(08)71019-7 apolinarska, k., pelechaty, m. & pukacz, a. (2011): caco3 sedimentation by modern charophytes (characeae): can calcified remains and carbonate δ13 c and δ18 o record the ecological state of lakes? a review.– stud. limnol. telmatol., 5, 55–66. avşar, u., jónsson, s., avşar, o. & schmidt, s. (2016): earthquake-induced soft-sediment deformations and seismically amplified erosion rates recorded in varved sediments of köyceğiz lake (sw turkey).– journal of geophysical research: solid earth, 121/6, 4767–4779. doi: 10.1002/2016jb012820 baker, a., routh, j. & roychoudhury, a.n. (2018): n-alkan-2-one biomarkers as a proxy for palaeoclimate reconstruction in the mfabeni fen, south africa.– organic geochemistry, 120, 75–85. doi: 10.1016/j.orggeochem.2018.03.001 bastviken, d., persson, l., odham, g. & tranvik, l. (2004): degradation of dissolved organic matter in oxic and anoxic lake water.– limnol. oceanogr., 49/1, 109–116. doi: 10.4319/lo.2004.49.1.0109 beilby, m.j. & casanova, m.t. (2014): the physiology of characean cells.– springer-verlag berlin heidelberg, 205 p. doi: 10.1007/978-3-642-40288-3 blašković, i. (1998): the two stages of structural formation of the coastal belt of the external dinarides.– geol. croat., 51/1, 75–89. boggs, s.j.r. (2013): principles of sedimentology and stratigraphy: new international edition (5e).– pearson higher ed usa, 568 p. bos, j.a.a., de smedt, p., demiddele, h., hoek, w.z., langohr, r., marcelino, v., van asch, n., van damme, d., van der meeren, t., verniers, j., boeckx, p., boudin, m., court-picon, m., finke, p., gelorini, v., gobert, s., heiri, o., martens, k., mostaert, f., serbruyns, l., van strydonck, m. & crombé,p. (2017): multiple oscillations during the lateglacial as recorded in a multi-proxy, high-resolution record of the moervaart palaeolake (nw belgium).– quat. sci. rev., 162, 26–41. doi: 10.1016/j.quascirev.2017.02.005 božičević, s. & benček, đ. (1983.): tektonsko – geomorfološke specifičnosti biokova i pojave urušnih vrtača i ledenica.– acta biokovica, 2, 157–166. clarke, a.h. (1979): gastropods as indicators of lake trophic stages.– the nautilus, 94/4, 138–142. currie, l.a. (2004): the remarkable metrological history of radiocarbon dating [ii].– journal of research of the national institute of standards and technology, 109, 185–217. doi:10.6028/jres.109.013 cvijanović, d., arsovski, m. & mihailov, v. (1981): karakteristike seizmičke aktivnosti u širem području biokova.– acta biokovica, 1, 23–34. daura, j., sanz, m., allué, e., vaquero, m., lópez-garcía, j.m., sánchez-marco, a., domènech, r., martinell, j., carrión, j.s., ortiz, j.e., torres, t., arnold, l.j., benson, a., hoffmann, d.l., skinner, a.r. & julià, r. (2017): palaeoenvironments of the last neanderthals in sw europe (mis 3): cova del coll verdaguer (barcelona, ne of iberian peninsula).– quat. sci. rev., 177, 34–56. doi: 10.1016/j.quascirev.2017.10.005 deino, a.l., kingston, j.d., glen, j.m., edgar, r.k. & hill, a. (2006): precessional forcing of lacustrine sedimentation in the late cenozoic chemeron basin, central kenya rift, and calibration of the gauss/matuyama boundary.– earth and planetary science letters, 247/1–2, 41–60. doi: 10.1016/j.epsl.2006.04.009 dillon, r.t. (2000): the ecology of freshwater molluscs.– cambridge university press, cambridge, 509 p. doi: 10.1017/cbo9780511542008 dragičević, i., prelogović, e., kuk, v. & buljan, r. (1999): recent tectonic activity in the imotsko polje area.– geol. croat., 52/2, 191–196. durn, g., ćorić, r., tadej, n., barudžija, u. & rubinić, v. (2014): bulk and clay mineral composition indicate origin of terra rossa soils in western herzegovina.– geol. croat., 67/3, 171–183. doi: 10.4154/gc.2014.13 durn, g. (2003): terra rossa in the mediterranean region: parent materials, composition and origin.– geol. croat., 56/1, 83–100. ford, d.c. & williams, p. (2007): karst hydrogeology and geomorphology.– wiley & sons, chichester, england, 562 p. doi: 10.1002/9781118684986 herak, ma., herak, d. & markučić, s. (1995): fault-plane solution for earthquake (1956-1995) in croatia and neighbouring regions.– geofizika, 12, 43–56. herak, ma., herak, d. & markučić, s. (1996): revision of the earthquake catalogue and seismicity of croatia, 1908-1992.– terra nova, 8, 86–94. doi: 10.1111/ j.1365-3121.1996.tb00728.x herak, mi. (1986): a new concept of geotectonics of the dinarides.– acta geologica, 16/l, 1–42. herak, mi. (1991): dinaridi, mobilistički osvrt na genezu i strukturu [dinarides – mobilistic view of the genesis and structure – in croatian].– acta geologica, 21/2, 35– 117. jarnuszewski, g. & meller, e. (2018): morphological and physical properties of dehydrated holocene carbonate limnic deposits in post-bog areas of nw poland.– journal of ecological engineering, 19, 136–142. doi:10.12911/22998993/79412 johnson, r.k., hallstan, s. & zhao, x. (2018): disentangling the response of lake littoral invertebrate assemblages to multiple pressures.– ecological indicators, 85, 1149–1157. doi: 10.1016/j.ecolind.2017.10.075 kingston, j.d., deino, a.l., edgar, r.k. & hill, a. (2007): astronomically forced climate change in the kenyan rift valley 2.7–2.55 ma: implications for the evolution of early hominin ecosystems.– journal of human evolution, 53/5, 487–503. leucci, g., margiotta, s. & negri, s. (2004): geophysical and geological investigations in a karstic environment (salice salentino, lecce, italy).– journal of environmental and engineering geophysics, 9/1, 25–34. doi: 10.4133/jeeg9.1.25 lunina, o.v. & gladkov, a.s. (2016): soft-sediment deformation structures induced by strong earthquakes in southern siberia and their paleoseismic significance.– sedim. geol, 344, 5–19. doi: 10.1016/j.sedgeo.2016.02.014 magaš, n., marinčić, s. & benček, đ. (1972): tumač ogk 1:100.000 list ploče k 33–35 [basic geological map of sfry 1:100000, geology of the ploče sheet – in croatian].– geološki institut beograd& geološki zavod zagreb, savezni geološki zavod, beograd, 46 p. marinčić, s., magaš, n. & benček, đ. (1972): osnovna geološka karta sfrj 1:100.00 list ploče k 33–35 [basic geological map of sfry 1:100000, ploče sheet – in croatian].– geološki institut beograd & geološki zavod zagreb, savezni geološki zavod, beograd. morellón, m., anselmetti, f.s., valero-garcés, b., giralt, s., ariztegui, d., sáezg, a., mata, m.p., barreiro-lostres, f., rico, m. & moreno, a. (2014): the influence of subaquatic springs in lacustrine sedimentation: origin and paleoenvironmental significance of homogenites in karstic lake banyoles (ne spain).– sedim. geol, 311, 96–111. doi: 10.1016/j.sedgeo.2014.07.004 mulder, t. & syvitski, j.p.m. (1995): turbidity currents generated at river mouths during exceptional discharges to the world oceans.– journal of geology, 103/3, 285–299. doi: 10.1086/629747 munsell soil color book (2013): munsell soil color charts with genuine munsell color chips.– macbeth division of kollmorgem instruments corporation, new windsor. noble, p.j., ball, g.i., smith, s.b. & zimmerman, s.h. (2015): holocene paleoclimate potential of fallen leaf lake sediment cores, tahoe basin, california, usa.– quaternary international, 387, 141. doi: 10.1016/j.quaint.2015.01.158 pełechaty, m., pukacz, a., apolinarska, k., pełechata, a. & siepak, m. (2013): the significance of chara vegetation in the precipitation of lacustrine calcium carbonate.– sedimentology, 60/4, 1017–1035. doi: 10.1111/sed.12020. pentecost, a. (1984): the growth of chara globularis and its relationship to calcium carbonate deposition in malham tarn.– field studies, 6/1, 53–58. pettijohn, f.j. (1975): sedimentary rocks (third edition).– harper & row, publishers, inc., 628 p. pilaar birch, s.e. & vander linden, m. (2018): a long hard road… reviewing the evidence for environmental change and population history in the eastern adriatic and western balkans during the late pleistocene and early holocene.– quat. int., 465/b, 177–191. doi: 10.1016/j.quaint.2016.12.035 platt, n. & wright, v.p. (1991): lacustrine carbonates: facies models, facies distributions and hydrocarbons aspects.– in: anadon, p., cabrera, l.i. & kelts, k. (eds.): lacustrine facies analysis, spec. publ. int. assoc. sedimentol., 13, 57–74. doi: 10.1002/9781444303919.ch3 pleničar, m. (1954): prispevek h geologiji cerkniškega polja.– proteus, xvii, 111–119. potter, p.e. & pettijohn, f.j. (1977): paleocurrents and basin analysis.– springerverlag, berlin, 550 p. doi: 10.1007/978-3-642-61887-1 reading, h.g. (1996): sedimentary environments. processes, facies and stratigraphy.– blackwell science ltd., oxford, 628 p. reineck, i.b. & singh, i.b. (2012): depositional sedimentary environments: with reference to terrigenous clastics.– springer science & business media, 439 p. retallack, g.j. (2001): soils of the past. an introduction to paleopedology.– blackwell science ltd., oxford, 404 p. rey, j., martínez, j., mediavilla, r., santisteban, j.i., castaño, s. & de la losa, a. (2017): geophysical characterization of stratigraphical surfaces: basin floor and sedimentological architectural elements of las tablas de daimiel (quaternary of southern-central spain).– journal of applied geophysics, 136, 387–399. doi: 10.1016/j.jappgeo.2016.11.020 romey, c., rochette, p., vella, c., arfib, b., andrieu-ponel, v., braucher, r., champollion, c., douchet, m., dussouillez, p., hermitte, d., mattioli, e., parisot, j.-c. & schwenninger, j.-l. (2014): geophysical and geomorphological investigations of a quaternary karstic paleolake and its underground marine connection in cassis (bestouan, cassis, se france).– geomorphology, 214, 402–415. doi: 10.1016/j.geomorph.2014.02.021 romić, m., bragato, g., zovko, m., romić, d., mosetti, d., galović, l. & bakić, h. (2014): the characteristics of soils developed from coastal paleosand (korčula island, croatia).– catena, 113, 281–291. doi: 10.1016/j.catena.2013.08.009 g eo lo gi a c ro at ic a geologia croatica 71/3162 rudersdorf, a., hartmann, k., yu, k., stauch, g. & reicherter, k. (2015): seismites as indicators for holocene seismicity in the northeastern ejina basin, inner mongolia.– in: landgraf, a., kübler, s., hintersberger, e. & stein, s. (eds.): fault rupture and earthquake hazards in slowly deforming regions. geological society, london, special publications, 432 p., 213–231. doi: 10.1144/sp432.6 scheidegger, a.e. (1965): a theory of varve formation.– international association of scientific hydrology, 10/1, 68–73. doi: 10.1080/02626666509493374 smrekar, a.a. (2000): cerkniško polje kot primer poseljenega kraškega ranljivega območja.– geographica slovenica, 33/1, 117–156. soulie-marsche, i., bieda, s., lafond, r., maley, j., baitoudji, m., vincent, p.m. & faure, h. (2010): charophytes as bio-indicators for lake level high stand at “trou au natron”, tibesti, chad, during the late pleistocene.– global planet. change, 72, 334–340. soulie-marsche, i. & garcia, a. (2015): gyrogonites and oospores, complementary viewpoints to improve the study of the charophytes (charales).– aquatic botany, 120, 7–17. doi:10.1016/j.aquabot.2014.06.003. shanmugam, g. (2017): global case studies of soft-sediment deformation structures (ssds): definitions, classifications, advances, origins, and problems.– journal of palaeogeography, 6/4, 251–320. doi: 10.1016/j.jop.2017.06.004 sondi, i. & juračić, m. (2010): whiting events and the formation of aragonite in mediterranean karstic marine lakes: new evidence on its biologically induced inorganic origin.– sedimentology, 57, 85–95. doi: 10.1111/j.1365-3091.2009.01090.x surić, m. & juračić, m. (2010): late pleistocene – holocene environmental changes – records from submerged speleothems along the eastern adriatic coast (croatia).– geol. croat., 63/2, 155–169. doi: 104154/gc.2010.13 şimşek, f. b. & çağatay, m.n. (in press): late holocene high resolution multi-proxy climate and environmental records from lake van, eastern turkey.– quat. int. terzić, j., šumanovac, f. & buljan, r. (2007): an assessment of hydrogeological parameters on the karstic island of dugi otok, croatia.– journal of hydrology, 343/1–2, 29–42. doi: 10.1016/j.jhydrol.2007.06.008 tomasović, m., perkić, d. & alduk, i. (2008): topografija stećaka u hrvatskoj.– in: tomasović, m. (ed.): stećci, katalog izložbe, galerija klovićevi dvori, zagreb, 293 p. trapote, m.c., vegas-vilarrúbia, t., lópez, p., puche, e., gomà, j., buchaca, t., cañellas-boltà, n., safont, e., corella, j.p. & rull, v. (2018): modern sedimentary analogues and integrated monitoring to understand varve formation in the mediterranean lake montcortès (central pyrenees, spain).– palaeogeogr. palaeoclimatol. palaeoecol., 496, 292–304. doi: 10.1016/j.palaeo.2018.01.046 tucker, m.e. (2008): sedimentary petrology – an introduction to the origin of sedimentary rocks 3rd edition.– wiley blackwell, 261 p. tucker, m.e. & wright, v.p. (1990): carbonate sedimentology.– blackwell science, oxford, 482 p. doi: 10.1002/9781444314175 van loon, a.j. & brodzikowski, k. (1987): problems and progress in the research on soft-sediment deformations.– sedim. geol., 50/1–3, 167–193. doi: 10.1016/00370738(87)90032-7 vlahović, i., tišljar, j., velić, i. & matičec, d. (2002): the karst dinarides are composed of relics of a single mesozoic platform: facts and consequences.– geol. croat., 55/2, 171–183. valvasor, j. w. (1689): die ehre dess hertzogthums crain.– laybach. i. theil, 696 p. vrabec, m. (1994): some thoughts on the pull-apart origin of karst poljes along the idrija strike-slip fault zone in slovenia.– acta carsologica, 23, 158–168. walker, m.j.c., berkelhammer, m., björck, s., cwynar, l.c., fisher, d.a., long, a.j., lowe, j.j., newnham, r.m., rasmussen, s.o. & weiss, h. (2012): formal subdivision of the holocene series/epoch: a discussion paper by a working group of intimate (integration of ice-core, marine and terrestrial records) and the subcommission on quaternary stratigraphy (international commission on stratigraphy).– journal of quaternary science, 27/7, 649–659. doi:10.1002/jqs.2565. weeks, a.m., de jager, n.r., haro, r.j. & sandland, g.j. (2017): spatial and temporal relationships between the invasive snail bithynia tentaculata and submersed aquatic vegetation in pool 8 of the upper mississippi river.– river res. applic., 33, 729–739. doi:10.1002/rra.3123 zolitschka, b. (2013): varved lake sediments.– in: elias, s.a. (ed.): encyclopedia of quaternary science (second edition), elsevier, amsterdam, 573–581. doi: 10.1016/b978-0-444-53643-3.00056-x zolitschka, b., francus, p., ojala, a.e.k. & schimmelmann, a. (2015): varves in lake sediments – a review.– quat. sci. rev., 117, 1–41. doi: 10.1016/j. quascirev.2015.03.019 08_in_memo_scavinicar.indd 103 vladimir bermanec: in memoriam professor emeritus stjepan šćavničar (31.10.1923–14.02.2011) in memoriam professor emeritus stjepan šćavničar (31.10.1923–14.02.2011) � doi: 104154/gc.2012.08 geologia croatica 65/1 103–107 zagreb 2012 geologia croaticageologia croatica stjepan šćavničar, professor emeritus of mineralogy at the faculty of natural sciences and mathematics, university of zagreb, passed away quietly at his home in zagreb, on 14 february 2011. he was one of a small group of devoted teachers and researchers who substantially helped to advance mineralogy and crystallography in croatia. professor šćavničar was born on 31 october 1923 in štrigova, near the town of čakovec in northern croatia. he obtained his bsc degree in geology at the faculty of natural sciences and mathematics (fnsm) in 1951, being one of this school’s earliest students after world war ii. soon after graduation, he began teaching courses in mineralogy and crystallography, paying special attention to details of morphology and structure. in 1956, on completion of his phd at the same university, šćavničar was appointed an assistant lecturer in the department of geology of the faculty of natural sciences and mathematics at the university of zagreb. a scholarship from the french government took him to paris where he spent the academic year of 1956/57 at the sorbonne. he and professor jean wyart (1902–1992), his host in the laboratory for mineralogy and crystallography, soon became friends for life. together they pioneered the modern hthp hydrothermal synthesis of beryl. returning from paris, šćavničar progressed through the ranks of assistant professor (1960–1965), associate professor (1965–1969) and full professor. he was the head of the institute of mineralogy and petrology from 1974 until his retirement in 1994. during his lengthy period as chair, the institute of mineralogy and petrology grew considerably in terms of staff, which also resulted in a substantially wider scope of research activities. he was elected professor emeritus in 2000. šćavničar also headed and developed another department, the division for materials research in the early days of the rudjer bošković institute in zagreb (1952–1974). under his chairmanship, both departments, the institute of mineralogy and petrology and the division for materials research were equipped with state-of-the-art equipment including modern instrumental arrays. he led and managed teams of young investigators who worked on the development of new methods and analytical techniques in the fi elds of crystallography, mineralogy and material research. some components of x-ray diffraction apparatus and spectrometers are still in use to this day. his contributions to crystal structural investigations opened the way for collaboration and the establishment of many scientifi c groups, not only in croatia but also beyond. it should be noted that the move of the institute of mineralogy and petrology to its present location was initiated during the fi nal year of šćavničar’s chairmanship. he was retired before the move was completed, but he was well involved in the entire process. geologia croatica 65/1geologia croatica 104 original scienific papers cited in current content journals (31) grdenić, d. & šćavničar, s. (1953): mercuric oxychloride as tri-chlor-mercuryoxonium chloride.– nature, 172, 584–586. šćavničar, s. & grdenić, d. (1955): the crystal structure of trichlor-mercury oxonium chloride.– acta cryst., 8, 275–279. šćavničar, s. (1955): the crystal structure of timercuric oxychloride, hgcl2 x 2hgo.– acta cryst., 8, 379–383. šćavničar, s. (1956): the crystal structure of oxy-mercuric-mercurous chloride, 2hgo • hg2c12.– acta cryst., 9, 956–957. šćavničar, s. (1960): the crystal structure of stibnite. a redetermination of atomic positions.– z. kristallogr., 114, 85–97. grdenić, d. & šćavničar, s. (1960): the lone-pair-bond-pair repulsion in the square pyramidal centrifugation of quinqueco-ordinated tervalent antimony.– proc. chem. soc., 147–148. šćavničar, s. (1960): the crystal structure of stibnite. a redetermination of atomic positions.– acta cryst., 13, 1031–1031. šćavničar, s. (1963): the crystal structure of mercury (ii) oxycyanide.– z. kristallogr., 118, 248–256. šćavničar, s. & prodić, b. (1965): the crystal structure of double nitrate octahydrates of thorium and bivalent metals.– acta cryst., 18, 698–702. herceg, m. & šćavničar, s. (1967): a new molybdenum cluster compound and x-ray investigation.– croat. chem. acta, 39, 137– 138. šćavničar, s. & matković, b. (1967): the molecular structure of bis (pyridine-n-oxide) copper(ii) nitrate.– chem. comm., p. 297. šljukić, m., matković, b., prodić, b. & šćavničar, s. (1967): preparation and crystallographic data of phosphates with common formula mim2iv(po4)3 (mi = li, na, k, rb, cs; miv = zr, hf).– croat. chem. acta, 39, 145–148. šćavničar, s. & matković, b. (1969): x-ray crystal structure analysis of bis (pyridine-n-oxide) copper (ii) nitrate, cu(c5h5no)2 (no3)2.– acta cryst., b 25, 2046–2055. ribar, b., nowacki, w., šljukić, m., šćavničar, s. & gabela, f. (1969): die kristallstruktur von zn(no3)2 x 2h2o.– z. kristallogr., 129, 305–317. kojić-prodić, b., matković, b. & šćavničar, s. (1971): the crystal structure of hydrazinium(+2) hexafl uorotitanate(iv), n2h6tif6.– acta cryst., b 27, 635–637. kojić-prodić, b., šćavničar, s. & matković, b. (1971): the crystal structure of hydrazinium(+2) hexafluorozirconate, n2h6zrf6.– acta cryst., b 27, 638–644. he was vice-dean (1968–1970) of fnsm and dean of the natural sciences departments (1984–1986). as dean of the faculty he took a leading role in strategic choices about the long-term development of science and technology in croatia. he was gruff, modest, friendly, tolerant, far-sighted and clear-minded, and an avid lover of art and bordeaux wines. his lectures were not always easy to follow, but they were always very interesting. it was characteristic for šćavničar to speak about his ongoing research in class and this was very much appreciated by his students. in 1973 šćavničar became an associate member of the croatian academy of sciences and arts (former yugoslav academy of sciences and arts), and was elected to full membership in 1990. šćavničar received the “rudjer bošković” scientifi c award in 1971, followed by a professorship of merit of the university of zagreb in 1989, the life-achievement award in 1991 and the roll of honour of the faculty of natural sciences and mathematics in 1996. professor šćavničar was a founding member of the croatian crystallographic association of the croatian academy of sciences and arts. he was the fi rst president of the croatian mineralogical association and president of the geochemistry council of croatian academy of sciences and arts. he was also an honorary member of the croatian geological society. he was on the editorial board of geološki vjesnik (now geologia croatica) for many years (from volume 37 – 1984 to 43 – 1990). professor šćavničar was a long-time member of the mine ralogical society of america, as well as other learned societies in croatia and abroad. he was nominated for scientist of the year in 2002 (ibc cambridge – international biographical center). stjepan šćavničar is survived by his wife biserka (form er morić), a daughter and two grandsons. stjepan šćavničar has been awarded a lifelong achievement award in 1991. vladimir bermanec stjepan šćavničar has been awarded a lifelong achievement award in 1991. geologia croatica 105 vladimir bermanec: in memoriam professor emeritus stjepan šćavničar (31.10.1923–14.02.2011) šćavničar, s. (1965): serpentin iz bosanskog petrovog sela. mineraloška studija [serpentine from bosansko petrovo selo. mineralogical study – in croatian].– acta geol., 4, (prir. istraž. jugosl. akad. znan. umjet., 34), 251–264. šćavničar, st. (1965): termičke, strukturne i kemijske karakteristike klorita s papuka.– geol. vjesnik, 18, 269–280. šćavničar, s. (1967): interstratifi kacija kod minerala glina. [interstratifi cation of clay minerals – in croatian].– izvještaj jugosl. centra kristalogr., jugosl. akad. znan. umjet., 2, 43–58. šćavničar, s., trubelja, f. & sijarić-pleho, g. (1968): mineralogical and chemical properties of herzegovinian bauxites. travaux com. intern. l’etude bauxites, oxydes, hydroxydes d’alum.– jugosl. akad. znan. umjet., 5, 45–62. šćavničar, s. (1969): orijentacija kaolinita i gipsa u kristalnom prostoru izmijenjenog biotita. (orientation of kaolinite and gypsum within the crystal space of transformed biotite).– geol. vjesnik, 22, 439–443. šćavničar, s. & trubelja, f. (1969): talk-serpentin-kloritska žila kod sela kupres u srednje-bosanskom škriljastom gorju [the talcserpentine-chlorite vein near the village of kupres in central bosnian shists-mountains – in croatian].– geol. vjesnik, 22, 445–467. šćavničar, s., međimorec, s. & marić, z. (1975): mineraloško ispitivanje gline iz rudnog tijela jezero ležišta omarska [mineralogical investigation of day from the ore body jezero of the omarska deposit – in croatian].– acta geol., 8/14 (prir. istraž. jugosl. akad. znan. umjet., 41), 269–275. marci, v., međimorec, s. & šćavničar, s. (1975): žilne pojave klorita u jugozapadnom dijelu psunja [vein assemblages of chlorite in southwestern part of mt. psunj (northern croatia) – in croatian].– geol. vjesnik, 28, 217–241. šćavničar, s., međimorec, s. & šćavničar, b. (1975): pumpellyite in the magmatic rocks of komiža.– bull. sci., a 20, p. 3. šćavničar, s. (1978): razvoj mineralogije u sr hrvatskoj od 1951– 1976 god.– geol. vjesnik, 30/2, p. 633. šćavničar, b. & šćavničar, s. (1979): autigeni celestin u vapnencima donjeg trijasa i evaporitnim sedimentima permotrijasa u dalmaciji [authigenic celestite in lower triassic limestones and permo-triassic evaporitic deposits in dalmatia (south croatia) – in croatian].– geol. vjesnik, 31, 279–286. majer, v. & šćavničar, s. (1982): razvoj mineralogije i petrologije magmatskih i metamorfnih stijena u sr hrvatskoj od 1977– 1981.– geol. vjesnik, 35, 236–238. šćavničar, s., krkalo, e., šćavničar, b., halle, r. & tibljaš, d. (1983): naslage s analcimom u poljanskoj (slavonija, sjeverna hrvatska) [analcim bearing deposits in poljanska, slavonia, northern croatia – in croatian].– rad jugosl. akad. znan. umjet., 404, (razr. prir. znan. knj. 19), 137–169. marci, v., šćavničar, s. & sijarić, g. (1984): novi podaci o vulkanskim stijenama ivanščice (sliv potoka železnice) [the new data about volcanic rocks of ivanščica mountain – in croatian].– geol. vjesnik, 37, 97–104. šćavničar, b., šćavničar, s. & šušnjara, a. (1984): vulkanogeno-sedimentni srednji trijas u području potoka suvaje (svilaja pl., vanjski dinaridi [the volcanic-sedimentary middle triassic in the suvaja brook area (mt. svilaja, outer dinarides) – in croatian].– acta geologica, 14/2 (prir. istraž. jugosl akad znan. umjet. 49), 35–82. sijarić, g., pamić, j., šibenik-studen, m. & šćavničar, s. (1985): struktumi oblici albita u mezozojskim spilitima i keratofi rima u bosni i hercegovini [structural forms of albites in the mesozoic spilites and keratophyres in bosnia and hercegovina) – in croatian].– posebna izd. glasnik zemalj. muz. bosne i hercegovine, 24, 1–110. kojić-prodić, b., šćavničar, s., liminga, r. & šljukić, m. (1972): the crystal structure of trihydrazinium hexafl uorochromate, (n2h5)3crf6.– acta cryst., b 28, 2028–2032. kojić-prodić, b., liminga, r. & šćavničar, s. (1973): the crystal structure of caesium-oxo-bis-oxalato-bisaquo-niobate(v) dihydrate, csnbo(c2o4)2 (h2o)2 x 2h2o.– acta cryst., b 29, 864– 869. pamić, j., šćavničar, s. & međimorec, s. (1973): mineral assemblage of amphibolites associated with alpine type ultramafi cs in the dinaric ophiolite zone (yugoslavie).– j. petrology, 14/1, 133–157. engel, p., nowacki, w., balić-žunić, t. & šćavničar, s. (1982): the crystal structure of simonite, tlhgas3s6.– z. kristallogr., 161, 159–166. balić-žunić, t., šćavničar, s. & engel, p. (1982): the crystal structure of rebulite, tl5 sb5 as8 s22.– z. kristallogr., 160, 109–125. balić-žunić, t., šćavničar, s. & grobenski, z. (1984): the structure of thorium (iv) dititanium (iv) oxide thtio.– croat. chem. acta, 57, 645–651. balić-žunić, t., šćavničar, s. & molin, g. (1988): the simmetry of prehnite and refi nament of its crystal structure.– z. kristallogr., 185, p. 599. balić-žunić, t. & šćavničar, s. (1988): the crystalochemical behaviour of thallium and lead in the lorandite – type sulfosalts.– nucl. instrum. meth., a 271, 304–307. balić-žunić, t., šćavničar, s. & molin, g. (1990): crystal structure of prehnite from komiža.– eur. j. mineral., 2, 731–734. bermanec, v., balen, d., šćavničar, s. & tibljaš, d. (1993): zn-rich magnetoplumbite from nežilovo, macedonia.– eur. j. mineral., 5, 957–960. bermanec, v. & šćavničar, s. (1993): magnetoplumbite from nežilovo, macedonia: crystal structure refi nement of zinc-rich magnetoplumbite.– neues jb. miner. monat., 11, 481–486. bermanec, v., šćavničar, s. & zebec, v. (1995): childrenite and crandallite from the stari trg mine (trepča), kosovo: new data.– miner. petrol., 52/3–4, 197–208. bermanec, v., holtstam, d., sturman, d., criddle, a.j., back, m.e. & šćavničar, s. (1996): nežilovite, a new member of the magnetoplumbite group, and the crystal chemistry of magnetoplumbite and hibonite.– can. mineral., 34/6, 1287–1297. radanović-gužvica, b., šćavničar, s. & zebec, v. (2000): a new crystallographic feature of barite from the balkan peninsula.– neues jb. miner. monat., 1, 15–33. tibljaš, d., šćavničar, s., molin, g. & slavković, r. (2004): authigenic mica in early miocene volcaniclastic rocks of the macelj area, hrvatsko zagorje, croatia.– neues jb. miner. monat., 2, 69–82. scientific papers in other journals (32) grdenić, d., šćavničar, s. & kesler, m. (1952): on the mercury phosphoiodide.– arhiv kem., 24, 61–65. grdenić, d. & šćavničar, s. (1953): the crystal structure of mercuric oxychloride, 2hgcl2 x hgo.– arhiv kem., 25, 109–112. šćavničar, s. & sabatier, g. (1957): action du chlorure de lithium sur les feldspaths alcalins.– b. soc. fr. mineral. cr., 80, 308– 317. wyart, j. & šćavničar, s. (1957): sythese hydrotermale du beril.– b. soc. fr. mineral. cr., 80, 395–396. šćavničar, s. & tajder, m. (1962): razvoj mineralogije i petrologije u nr hrvatskoj od 1951 do 1961.– geol. vjesnik, 15/1, 19–26. šćavničar, s. & šinkovec, b. (1964): talk-kloritni škriljci na istočnim obroncima psunja [talc-clorite-shists from the east slopes of the psunj mountain – in croatian].– geol. vjesnik, 17, (1963), 119–134. geologia croatica 65/1geologia croatica 106 bermanec, v. & šćavničar, s. (1985): korelacija strukturnih kemijskih i fi zičkih svojstava plagioklasa.– godišnjak. jugosl. asoc. mineral., 27–33. balić-žunić, t.& šćavničar, s. (1985): kristalokemija talijskih sulfosoli iz alšara. mineralogija.– godišnjak jugosl. asoc. mineral., 1, 35–47. tibljaš, d. & šćavničar, s. (1985): zeoliti u eocenskom konglomeratu kod velešnje (zapadno od kostajnice). mineralogija.– godišnjak jugosl. asoc. mineral., 1, 207–215. bermanec, v. & šćavničar, s. (1987): x-ray and ir investigation of the whole series of „low temperature“ plagioclases.– god. jugosl. centra kristal., 22, p. 59, zagreb. marci, v., šćavničar, s. & sijarić, g. (1988): klastolave i brečolave iz dugog potoka (železnica, ivanščica) [clastolavas and brecciated laves from dugi potok (železnica, ivanščica) – in croatia].– rad jugosl. akad. znan. umjet., 441, (razr. prir. znan. knj., 23), 85–95. tibljaš, d. & šćavničar, s. (1988): mineraloško istraživanje klinoptilolita, plagioklasa i seladonita iz tufa donjeg jesenja u hrvatskom zagorju.– geol. vjesnik, 41, 99–117. bermanec, v., balen, d., oberhansli, r. & šćavničar, s. (1993): hedyphane from nežilovo, macedonia.– geol. croat., 46, 229–232. bermanec, v, boev, b., šijakova-ivanova, t. & šćavničar, s. (1999): association of the world biggest crystals of the brucite, mg(oh)2, from ‘ržanovo macedonia.– geologica macedonica, 13, 85–89. šćavničar, s., bermanec, v., kniewald, g., barišić, d. & oreščanin, v. (2007): uranium minerals in the radlovac series metasediments at mt. papuk, croatia.– geol. croat., 60/2, 165–171. chapters in books tibljaš, d. & šćavničar, s. (2007): nalazišta zeolitnog tufa na području krapine. prirodni zeolitni tuf iz hrvatske u zaštiti okoliša.– institut za međunarodne odnose, 2007, zagreb. contributions to scientific meetings (2) biševac, v., tibljaš, d., kurtanjek, d., miklaužić, s., balen, d. & šćavničar, s. (2008): clay minerals in zeolite deposit of poljanska, croatia.– mineralogia, special papers, 33, 4th mid-european clay conference 2008 (mecc08). krakow: wydaw nictwo naukowe, 47–47. zebec, v., šćavničar, s., wegner, r., bermanec, v., žigovečki gobac, ž. & čobić, a. (2009): unusual habit of microcline from alto da cabeça pegmatite, parelhas, rio grande do norte, brazil.– estudos geológicos. recife, brazil, 354–356. scientific papers in books of abstracts with international review radanović-gužvica, b., šćavničar, s. & zebec, v. (2000): poredbena analiza parametara jedinične ćelije kristala barita različitih tipova habitusa. zbornik radova 2. hrvatskog geološkog kongresa. zagreb– institut za geološka istraživanja, 361–365. books of abstracts from scientific meetings (27) sijarić, g. & šćavničar, s. (1972): istraživanje serpentinskih minerala iz rudnika magnezita miljevica kod kladnja. vii kongr. geol sfrj (zagreb), 2, 319–334. sijarić-pleho, g. & šćavničar, s. (1972): istraživanja serpentinskih minerala iz rudnika magnezita miljevica kod kladnja [investigation of serpentine minerals from magnesite mine miljevica near kladanj – in croatian].– vii kongr. geol. sfrj (predavanja), 2, 319–334, zagreb. šćavničar, s., međimorec, s. & šćavničar, b. (1975): pumpellyite in the magmatic rocks of komiža.– bull. sci. cons. acad. yougosl (a), 20/1–2, 3–1, zagreb. sijarić, g., trubelja, f. & šćavničar, s. (1976): diaspore bauxites of the grmeč mountain (bosnia). travaux com. intern. pour l’étude bauxites l’alumine et d’alum. (icsoba) 13 (1976). symp. on advances in geology, geochem. and treatment of bauxites dubrovnik 1975, 2, 13, 115–124, zagreb. šćavničar, s. (1976): neobično velika koncentracija gibbsita u netopivom ostatku vapnenca sa otoka paga.– zbornik radova iv jugoslavenskog simpozijuma o istraživanju i eksploataciji boksita, herceg novi, 71–72. brajdić, v. & šćavničar, s. (1978): prehnit u gabropegmatitu kod olova (sjeveroistočna bosna).– zbornik radova ix kongresa geologa jugoslavije, sarajevo, 483–488. šćavničar, s. (1978): new data on the insoluble residium of limestone.– 4th international congress of icsoba, athens, 2, 765–772. šćavničar, s., balić-žunić, t. & krstanović, i. (1980): the crystal structure of prehnite. (oh)2 ca2 al si3 al1010, redetermined.– collected abstracts of ima 12. general meeting. or1eans, 4–6, p. 189, or1eans. marci, v., šćavničar, s. & sijarić, g. (1982): petrografi ja vulkanskih stijena ivanščice (sliv potoka železnice) [petrogenesis of the volcanic rocks of ivanščica (river železnica) – in croatian].– 10. jub. kongr. geol. jugosl., budva, 1, 329–334. šćavničar, s., šćavničar, b. & krkalo, e. (1982): analcim u polimikritskoj petrografskoj asocijaciji (južno područje papukasjeverna hrvatska) [analcime in polymict petrographic association southern foot of papuk mountain-north croatia – in croatian].– 10. jub. kongr. geol. jugosl, budva, 1, 401–410. balić-žunić, t., šćavničar, s., engel, p. & n.w. (1983): prilog kristalokemiji talijskih sulfosoli.– 1. simp. jugosl. asoc. minera1., aranđelovac, p. 184. bermanec, v. & šćavničar, s. (1984): korelacija strukturnih kemijskih i fi zičkih svojstava plagioklasa.– 2. simp. jugosl. asoc. mineral., kopaonik. šćavničar, b., šćavničar, s. & šušnjara, a. (1984): volcanic, volcaniclastic and sedimentary svilaja mountain (south croatia, yugoslavia).– 5. europ. reg. meeting sediment. intern. assoc. sediment. marseille. tibljaš, d. & šćavničar, s. (1984): zeoliti u eocenskom konglomeratu kod velešnje (zapadno od kostajnice).– ii. simpozij jam kopaonik, izvodi referata-sadržaji, 3–4. balić žunić, t. & šćavničar, s. (1986): the crystallochemical behaviour of thallium and lead in the lorandite-type sulfosalts.– proceedings of the international conference on solar neutrino detection, dubrovnik 1986. šćavničar, s. & balić žunić, t. (1986): crystallochemistry of tl minerals.– proceedings of the workshop on the feasibility of the solar neutrino detection with 205 pb by geochemical and accelerator mass spectroscopical measurements, munich 1985. gsi-86-9 report. tibljaš, d. & šćavničar, s. (1987): possibilities and methods of distinction of species within heulandite group.– xxii konferencija jugoslavenskog centra za kristalografi ju, mostar. godišnjak jugoslavenskog centra za kristalografi ju, 22, p. 59. bermanec, v. & šćavničar, s. (1989): anomalous optical properties of epidote, childrenite and prehnite.– 6. jugosl.-ital. crist. conf. with 24. conf jugosl. centre crystall., pula., p. 859. geologia croatica 107 vladimir bermanec: in memoriam professor emeritus stjepan šćavničar (31.10.1923–14.02.2011) bermanec, v., tibljaš, d., šćavničar, s. & kniewald, g. (1990): karakterizacija konstituenata strukturnih kanala berila [characterization of the constituents of the structural channels in beryl – in croatian].– 12. kongr. geol. jugosl., ohrid, 2, 3–4. šćavničar, s. & tibljaš, d. (1992): opal – wrong example for amorphous mineral.– i. joint slovenian-croatian crystallographic meeting, otočec, book of abstracts, p. 49. bermanec, v., balen, d., šćavničar, s. & tibljaš, d. (1992): zincian magnetoplumbite from nežilovo, macedonia.– i. joint slovenian-croatian crystallographic meeting, otočec, book of abstracts, p. 50. bermanec, v., balen, d., šćavničar, s. & tibljaš, d. (1995): nežilovit novi mineral iz nežilova, makedonija.– i. hrvatski geološki kongres, opatija. knjiga sažetaka, p. 17. tibljaš, d., šćavničar, s., slavković, r. & bermanec, v. (1996): celadonite in pyroclastic rocks from hrvatsko zagorje – problem of determination.– 5th slovenian-croatian crystallographic meeting, book of abstracts, p. 23. tibljaš, d., šćavničar, s. & slavković, r. (1997): zeolites in the early miocene pyroclastic rocks from hrvatsko zagorje, nw croatia.– 5th international conference on the occurrence, properties, and utilization of natural zeolites – ischia, program and abstracs. 287–289. tibljaš, d., šćavničar, s., bermanec, v. & slavković, r. (1998): celadonite-family mica in pyroclastic rocks from hrvatsko zagorje (croatia).– 17th general meeting international mineralogical association. toronto: international mineralogical association, a159. tibljaš, d., šćavničar, s., cochemé, j.-j. & leggo, p. (1998): zeolites in pyroclastic rocks from pannonian part of croatia.– zeolite workshop ‘98. séance spécialisée de la société géologique de france. aix-en-provence. tibljaš, d., oršulić, d. & šćavničar, s. (2000): crystallochemical investigation of augite from basaltic andesite from donje jesenje (hrvatsko zagorje, croatia).– ninth slovenian-croatian crystallographic meeting, ljubljana, slovenska akademija, p. 46. unpublished contributions to scientific meetings tibljaš, d., oršulić, d. & šćavničar, s. (2000): rietveld refi nement of augite from basaltic andesite from donje jesenje (croatia).– vii. workshop powder diffraction – structure determination and refi nement from powder diffraction data. bayreuth. plenary lectures tibljaš, d. & šćavničar, s. (2006): zeolite deposits in croatia.– 3rd mid-european clay conference – mecc’06 abstracts book. zagreb, pmf & rgnf, 11–11. other lectures tibljaš, d. & šćavničar, s. (2007): zeoliti u piroklastitima hrvatskog zagorja.– odbor za geokemiju hazu. supervisering bermanec, v. (1986): korelacija rezultata istraživanja fi zičkih, kemijskih i strukturnih svojstava plagioklasa. blažević, z. (1964): glinene frakcije u sirovinama za proizvodnju cementa. carin, v. (1980): utjecaj po4-grupa na optičke i mikrostrukturne karakteristike i reaktivnost dikalcijevih silikata. dužević, d. (1970): fazne promjene kod sinteriranja i rezanja. grobenski, z. (1971): kristalna struktura torij-dititan(iv)-oksida. herceg, m. (1966): rendgenska strukturna istraživanja spojeva četverovalentnog molibdena. kniewald, g. (1981): stabilnost i taloženje urana (v) u alkalnim otopinama i njegova geokemijska aktivnost. luić, m. (1981): stabilizacija visokotemperaturnih modifi kacija dikalcij silikata pomoću v2o5 i moo3. međimorec, s. (1977): mineralne asocijacije žila u jugozapadnom dijelu psunja. prodić, b. (1963): kristalna struktura dvostrukih nitrata torija i nekih dvovalentnih metala. prohić, e. (1980): mineralogija glina iz neogenskih piroklastita i boksita sinjskog polja. radanović-gužvica, b. (1995): morfološke i kemijske značajke barita odabranih iz zbirke hrvatskog prirodoslovnog muzeja u zagrebu. sijarić, g. (1968): analiza faznog sastava nekih serpentine bosne. slovenec, d. (1976): biotiti iz genetski različitih stijena papuka. šljukić, m. (1966): strukturna istraživanja dvostrukih fosfata torija odnosno urana s alkalnim metalima. tibljaš, d. (1987): mineraloška istraživanja zeolita iz kenozojskih sedimenata kod velešnje na baniji i donjeg jesenja u hrvatskom zagorju. doctoral theses: bermanec, v. (1992): kristalokemijske karakteristike minerala iz asocijacija koje sadrže barijske silikate. balić-žunić, t. (1984): određivanje kristalne strukture dviju talijskih sulfosoli. kniewald, g. (1991): geokemija urana (v) u prirodnim vodama i sedimentacijskim sustavima. tibljaš, d. (1996): zeoliti i drugi produkti alteracijskih procesa u oligocenskim i donjomiocenskim piroklastitima na širem području macelja. rememberances šćavničar, s. (1981): in memoriam akademiku luki mariću održan 17. ožujka 1980. godine u palači akademije.– spomenica pre minulim akademicima, 10, 29–33, zagreb. šćavničar, s. (1983): miroslav tajder (nekrolog).– geol. vjesnik, 36/1, 295–301. šćavničar, s. (1984): ljudevit barić (1902–1984).– god. jugosl. centra kristal. šćavničar, s. (1984): miroslav tajder (1909–1983). nekrolog.– ljetopis jugosl. akad. znan. umjet. za 1983, 87/1, 560–562. geologia croatica 65/1geologia croatica 108 2019 | 72/3 | 179–193 | 13 figs. | 1 tab. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the vinodol valley is a 20 km long nw‒se oriented valley which runs parallel to the ne adriatic coastline, stretching from križišće in the nw to novi vinodolski in the se. the area of the bakar bay represents its geomorphological and geological extension towards the nw (fig. 1). the most important geological investigation of the wider area of the vinodol valley and bakar bay was undertaken for the basic geological map of sfry at a 1:100,000 scale (šušnjar et al., 1970). accompanying explanatory notes (grimani et al., 1973) also include a review of previous studies. in addition to these geological investigations associated with the basic geological map and its explanatory notes, the most important geological and structural studies of the vinodol valley were those by blašković (1991, 1997, 1998, 1999, 2005), in which he proposed a tectonic concept of the vinodol valley area. the area of the vinodol valley and bakar bay was investigated as a seismotectonically active area by prelogović et al. (1981, 1982, 1995), herak et al. (1996, 2017), markušić & geological and structural setting of the vinodol valley (nw adriatic, croatia): insights into its tectonic evolution based on structural investigations damir palenik1*, dubravko matičec1, ladislav fuček1, bojan matoš2, marijan herak3 and igor vlahović2 1 croatian geological survey, department of geology, sachsova 2, hr-10000 zagreb, croatia; (*corresponding author: dpalenik@hgi-cgs.hr) 2 university of zagreb, faculty of mining, geology and petroleum engineering, department of geology and geological engineering, pierottijeva 6, hr-10000 zagreb, croatia 3 university of zagreb, faculty of science, department of geophysics, horvatovac 95, hr-10000 zagreb, croatia doi: 10.4154/gc.2019.13 abstract the area of the vinodol valley and bakar bay represents a nw‒se oriented valley in the nw adriatic characterised by prominent historical and instrumentally recorded seismicity. as part of the greater geodynamic domain including the ilirska bistrica–rijeka–senj seismogenic fault zone, new geological and structural data addressing the tectonic evolution of the area were collected in order to better understand the focal mechanisms of previous earthquakes and to enable identification of potential seismogenic sources. mapped informal lithostratigraphic units mostly correspond to the upper cretaceous, palaeogene and quaternary successions described in other parts of the external dinarides. however, a shorter stratigraphic range of the gornji humac fm., the youngest cretaceous unit in the study area, was determined and suggests that the uplifted area in the central nw part of the adriatic carbonate platform already comprised several thousand km2 (from w and nw istria to krk and vinodol area) at the end of the turonian. structural measurements of the fault planes in the study area generally correspond to the existing structural model of the tectonic evolution of the dinarides. however, in contrast to the sw vergences typical of the dinarides, ne-vergent reverse structures are common, especially along the sw margin of the vinodol valley. cross-cutting relationships suggest that transpressional (nw–se and ne–sw striking dextral and sinistral faults) and extensional features (nw–se and ne–sw striking normal faults) are structurally concurrent or younger than the reverse faults, suggesting a change in the palaeostress field during the neogene–quaternary, with prevalent transpression and radial extension. comparison of results of the palaeostress field analysis and the constructed synthetic focal mechanisms on one side, with available focal mechanism solutions for earthquakes within the ilirska bistrica–rijeka–senj seismogenic fault zone on the other, shows a favourable orientation of the observed nw‒se and ne‒sw striking faults with respect to the recent compressional/transpressional stress field (n‒s oriented p-axis), indicating these as potential seismogenic sources within the study area. herak (1999), herak & herak (2017), and ivančić et al. (2018). these authors reported data on instrumental and historical seismic activity in the area and discussed the potential seismic sources. research presented here was performed in the framework of two ongoing scientific projects funded by the croatian science foundation (hrzz): velebit (grant no. ip-2014-09-9666) and geosekva (grant no. ip-2016-06-1854). the velebit project represents a multidisciplinary research approach addressing correlation of seismological data and tectonic framework in the neighbouring velebit mt. region, which is characterised by low seismicity and weak to moderate magnitude (m ≤ 5) earthquakes at shallow depths. the main research objectives of the geosekva project are the production of new geological maps (at 1:25,000 and 1:50,000 scales) and 3d geological models of selected structures in the wider kvarner region, as well as the broadening of the seismic station network and construction of a relevant seismotectonic model of the kvarner region. article history: manuscript received january 28, 2019 revised manuscript accepted may 31, 2019 available online october 31, 2019 keywords: nw adriatic, vinodol valley, bakar bay, sw and ne vergences, compression/transpression, neotectonic activity, focal mechanism solutions, seismicity g eo lo gi a c ro at ic a geologia croatica 72/3180 the main focus of the research in the vinodol valley was the geological mapping from križišće in the nw to kričina in the se accompanied by detailed structural-geological research of the vinodol valley and bakar bay (its continuation towards the nw). such investigation, together with new data on the focal mechanisms of previous earthquakes could contribute to greater understanding of the tectonic evolution of the study area, including fault kinematics and identification of potential seismogenic structures. 2. methodology 2.1. geological mapping of the study area the first phase of the research was focused on production of the new geological map of the vinodol valley and its border areas based on lithostratigraphic principles. the central part of the vinodol valley has been mapped at 1:5,000 scale, while the marginal parts were mapped at 1:25,000 scale. due to the intense tectonics, thicknesses of individual lithostratigraphic units were estimated from geological cross-sections and compared with contemporaneous lithostratigraphic units from neighbouring areas. 2.2. structural-geological investigation and analysis structural measurements were performed along the sw and ne edges of the vinodol valley as well as in the bakar bay. within an approximately 30 km long and 1–5.5 km wide area, structural data on outcrop-scale fault slips were collected. during analysis, for determination of fault kinematics in relation figure 1. location map and schematic geological map of the investigated and wider areas of the vinodol valley and bakar bay. modified from the basic geological map of the republic of croatia 1:300,000 (hgi, 2009). g eologia c roatica palenik et al.: geological and structural setting of the vinodol valley (nw adriatic, croatia): insights into its tectonic evolution based on structural investigations 181 to the past and present stress fields, we used data of field measurements of dip direction and dip angle of fault planes and orientation of carbonate slickensides defined by azimuth and plunge, and, wherever possible, their sense of movement. despite the relatively weathered outcrops and steep terrain, more than 120 sets of shear joint/fault planes data were gathered at 127 stations along the ne and sw margins of the vinodol valley and bakar bay. in some places, overlapping and crosscutting relationships between the observed striations enabled the relative temporal comparison of deformation. based on kinematic criteria, the structural data were separated into compatible datasets and processed by tectonics fp software (ortner et al., 2002). using the p–t axis method (turner, 1953; marrett & allmendinger, 1990) theoretical maximum (σ1), intermediate (σ2) and minimum stress axes (σ3) were calculated, whereas using the computed right dihedra method (angelier & mechler, 1977) synthetic focal mechanisms for the analysed fault segments were determined, i.e., palaeo-synthetic focal mechanisms as representations of the palaeostress fields. 3. results 3.1. geological mapping of the vinodol valley geological mapping determined that both margins of the vinodol valley are in general fault-bounded, whereas earlier proposals suggested that only the ne margin was fault bounded (šušnjar et al., 1970). along the ne edge of the vinodol valley reverse faults are characterised by tectonic transport to the sw, while those along the sw edge of the vinodol valley mostly indicate the opposite direction of tectonic transport, towards the ne, which is, although quite rare in the dinarides, very common in the structures of the neighbouring velebit mt. and krk island (vlahović et al., 2012; środoń et al., 2018; tomljenović et al., 2018). in addition to a completely new detailed lithostratigraphic subdivision of deposits, this is one of the key improvements in respect to the previous geological map of the area (šušnjar et al., 1970). on the basis of the geological map (fig. 2) five transverse geological cross-sections of the vinodol valley have been constructed (fig. 3). 3.2. lithostratigraphic units of the vinodol valley previous geological maps were based on the chronostratigraphic approach (šušnjar et al., 1970; blašković, 1999), so the map presented here is the first one based on lithostratigraphic principles. upper cretaceous lithostratigraphic units were named after, and compared to, the informal lithostratigraphic units already defined in other areas of the external dinarides (gušić & jelaska, 1990). a total of three upper cretaceous, three palaeogene and four quaternary units have been described in the study area. 3.2.1. upper cretaceous the oldest informal lithostratigraphic unit of the vinodol valley is the cenomanian milna fm., corresponding to the succession at the locus typicus – the island of brač (gušić & jelaska, 1990). it is composed of well-bedded limestones of a light brownfigure 2. geological map and schematic geological column of the vinodol valley from križišće to kričina. g eo lo gi a c ro at ic a geologia croatica 72/3182 grey colour composed of mudstones to wackestones and peloid– bioclastic packstones and grainstones with variable amounts of radiolitid rudist debris and rare ostreid shells. rudist floatstones and/or rudstones are relatively rare, as are layers containing chondrodonts and llh stromatolites, indicating deposition in shallow subtidal to peritidal environments. the microfossil assemblage includes the benthic foraminifera chrysalidina gradata d’orbigny, nummuloculina regularis philippson, broeckina (p.) balcanica cherchi et al., pseudolithuonella reicheli marie and alveolinids, indicating a middle to upper cenomanian age. macrofossils are relatively rare, represented by indeterminate radiolitid rudists and chondrodont shells. the thickness of the milna fm. may be estimated at c. 250 m (not including the lower part of the unit which does not crop out in the study area). global relative sea-level rise during the late cenomanian‒ early turonian (haq et al., 1987; hardenbol et al., 1998) was also characterised by the widespread oceanic anoxic event 2 figure 3. transverse geological cross-sections of the vinodol valley. g eologia c roatica palenik et al.: geological and structural setting of the vinodol valley (nw adriatic, croatia): insights into its tectonic evolution based on structural investigations 183 (oae2; schlanger & jenkyns, 1976) which, in the area of the adriatic carbonate platform, is recognized as an informal lithostratigraphic unit – the sv. duh fm. (gušić & jelaska, 1990). in the studied area the unit is composed of thick-bedded light brownish mudstones and mudstone‒wackestones. besides a variable, but significant amount of pithonelomorphic calcispheres (pithonella ovalis (kaufmann), pithonella sphaerica (bonet) and pithonella innominata (bonet)) rocks of this unit contain rare indeterminate planktonic foraminifera, and in the lower and upper part shallow-marine ostracods and miliolids as well as bioclasts of gastropods and bivalves. the sv. duh fm. was deposited within temporary drowned platform environments, and transitions from the underlying and to the overlying shallow-marine deposits are gradual. based on the superposition, microfossil assemblage and similar deposits in neighbouring istria (vlahović et al., 2002) stratigraphic age of sv. duh fm. may be estimated as upper cenomanian to lower turonian. due to intense post-sedimentary tectonics in the study area thickness of deposits cannot be measured directly, but may be approximated at 130‒150 m. the gornji humac fm. (first established on the island of brač by gušić & jelaska, 1990) represents the youngest cretaceous deposits in the study area, cropping out along the slopes of the vinodol valley and representing the footwall of the transgressive palaeogene foraminiferal limestones. it is composed of fenestral mudstones, mudstone‒wackestones with benthic foraminifera, calcareous algae, ostracods, small bioclasts and peloids, packstones with peloids and benthic foraminifera and relatively rare rudist floatstones. they were deposited in re-established peritidal environments and in places contain numerous decastronema (aeolisaccus) kotori (radoičić) and thaumatoporella parvovesiculifera (raineri), microfossils typical for this unit over the entire adriatic carbonate platform area. findings of the benthic foraminifera pseudocyclammina sphaeroidea gendrot indicates an upper turonian age for the deposits of this lithostratigraphic unit. in the study area, the uppermost part of the gornji humac fm. deposits is very karstified, more or less intensely recrystallized and coloured yellowish to reddish due to a very long stratigraphic hiatus (its duration may be estimated at c. 35–40 my). therefore, the total thickness of the gornji humac fm. varies laterally from c. 70 to around 100 m. 3.2.2. the palaeogene eocene foraminiferal limestones crop out along the slopes of the vinodol valley, transgressively overlying the upper cretaceous deposits of the gornji humac fm. this unit is characterised by significant lateral and vertical facies diversity, probably caused by variable palaeorelief resulting in the mixing of organisms from different environments. therefore, although a general deepeningupward trend is recognizable, foraminiferal limestones in the study area cannot be separated into sub-units usually named after predominant benthic foraminifera (from older and shallower to younger and deeper facies zones the usual sequence is from miliolid, through alveolinid and nummulitid to orthophragmid bearing limestones). these limestones are mostly represented by wackestones and/or packestones with variable amounts of foraminifera tests and other bioclasts. younger part of the deposits are characterised by the predominance of orthophragmids containing glauconite and a few other non-carbonate bioclasts. the estimated thickness of foraminiferal limestones in the study area is c. 200 m, and they are of lower–middle eocene age. transitional deposits are a succession of blueish to grey marlstones with 20–30 cm clayey limestone intercalations, representing a gradual deepening, i.e. transition from shallow-marine foraminiferal limestones to deep-marine flysch deposits. they are most clearly visible along the ne margin and in the se part of the vinodol valley. this unit is characterised by glauconite grains, both detrital and diagenetic in origin. in the lower part, sea urchins are common in some beds, while the upper part of the unit often contains irregular chert nodules. the estimated thickness of the transitional deposits in the study area is about 60 m, and based on superpositional relationships they are probably of middle eocene age. flysch deposits are represented by the alternation of medium-sized, well-sorted carbonate/quartz/mica sandstones commonly showing normal gradation and grey-blue marls. however, sandstones are not regularly distributed since they are much more common in the nw part of the vinodol valley while in its se part marls predominate. the flysch deposits are usually considered to be of the middle to upper eocene age (grimani et al., 1973), although some studies in neighbouring areas indicate a possibly younger age (šparica et al., 2005; mikes et al., 2008). although the flysch deposits are mostly covered by quaternary deposits their thickness in the study area probably does not exceed 350 m, as estimated from geological profiles. 3.2.3. quaternary rockfall breccias cover marginal areas of the vinodol valley and are characterised by a variable but generally high degree of lithification by carbonate cements. they consist mainly of unsorted limestone debris of typically variable stratigraphic ages, although some breccias contain clasts of only one lithostratigraphic unit, depending on their source area. the stratigraphic age of some completely lithified breccias may be probably even older than the quaternary. deluvial-proluvial deposits are represented by chaotic masses of angular to slightly rounded, unsorted limestone fragments ranging in size from mmto metre-sized blocks within a mostly reddish clayey matrix derived mostly from the mediterranean red soil (terra rossa). alluvial deposits – river and stream beds of the vinodol valley are often filled with gravels characterised by variable degrees of roundness and different fragment sizes. the material for these deposits mainly originates from the carbonate hinterland (cretaceous and palaeogene limestones) and partly from the sandstone horizons within the flysch deposits. flood plains are characterised by the deposition of fine-grained sands, silty mud and clay. rockfall deposits – active, unlithified rockfall deposits in the form of talus are located along the steep margins of the vinodol valley. they are more frequent and of larger dimensions along the ne valley margins. their fragments are angular and of different sizes, being the result of erosion of the steep carbonate cliffs of the vinodol valley and its immediate hinterland. 3.3. structural data analysis results within the vinodol fault zone within the structural field investigations in the study area, along the ne and sw margins of the vinodol valley and bakar bay, i.e. the vinodol fault zone (vfz; fig. 4) more than 120 shear joint/ fault plane data on 127 geological stations have been collected (fig. 4). according to the structural measurements, the area of the vfz can be subdivided into the ne vinodol fault zone (nevfz) and the sw vinodol fault zone (swvfz) (fig. 4). faults are characterised by both dip-slip and strike-slip kinematics, as well as oblique-slip kinematics characterised by a predomg eo lo gi a c ro at ic a geologia croatica 72/3184 inant dip-slip reverse component. in the ne vinodol (nevfz) and sw vinodol (swvfz) fault zones (fig. 4) kinematic criteria were used to separate the collected structural data into compatible structural datasets. within the vinodol fault zone, along the ne and sw margins of the vinodol valley and bakar bay (nevfz and swvfz; fig. 4), 48 and 72 fault planes were measured in the upper cretaceous and palaeogene carbonate rocks, respectively. those fault planes show predominant nw‒se and ne‒sw strike directions. with respect to the fault kinematics, data collected along the nevfz show 19 fault planes with strike-slip kinematics and 29 fault planes with dip-slip kinematics, out of which 8 have normal and 21 exhibit reverse kinematics. field structural measurements in the swvfz area encompassed 36 observed fault planes with strike-slip kinematics and 36 fault planes with dip-slip kinematics, i.e. 18 normal and 18 reverse kinematics. taking into account the kinematic criteria, the three aforementioned main categories were subdivided into compatible fault groups and fault group subsets (fig. 5). results of structural analysis in the vfz, i.e. nevfz and swvfz show that observed reverse fault planes can be separated into three fault groups and six group subsets (fig. 5 and table 1). the first group of observed reverse faults (vfz/rf1) comprise data of similar fault kinematics measured both along the ne and sw margins of the vfz. in general it is characterised by two fault group subsets i.e. conjugate fault pairs characterised by the nw‒ se strike, dipping both towards the ne and sw (dip angle c. 60°) (table 1). the first subset with an average ne dip direction and sw-directed tectonic transport (figs. 5–7) indicates thrusting of the upper cretaceous deposits and palaeogene foraminiferal limestones over younger palaeogene clastic deposits. it was predominanty observed in the nw and central parts of the nevfz (fig. 3; see structural diagrams for the vfz/rf1 group in the fig. 5 and table 1 for details). the second subset of fault planes is characterised by an average sw dip direction and ne-directed tectonic transport and was measured within the main thrusting fault zone along the sw margin of the vinodol valley, generally indicating ne tectonic transport (see cross-sections in the fig. 3, structural diagrams for the group vfz/rf1 in the fig. 5 and table 1). in the se part and along the ne margin of the vinodol valley, older upper cretaceous deposits (the milna fm.) are thrust over the palaeogene foraminiferal limestones and clastic rocks, whereas along the sw margin of the vinodol valley palaeogene foraminiferal limestones are thrust over the eocene flysch deposits (see figs. 3 and 8). the slight bending of the nevfz in its central part (in the vicinity of tribalj; figs. 2 and 3) implies also a slight change of the fault’s strike and slickenside orientation, which suggests the transition from pure reverse dip-slip motion to locally reverse, dextral/ sinistral oblique-slip motions (see fault planes with sw-dipping directions on group ne/rf1 diagram in the fig. 5). structural analysis of the representative palaeostress field using the p–t axis method (turner, 1953; marrett & figure 4. topographic map of the vinodol valley and bakar bay, i.e. the vinodol fault zone (vfz) with 127 locations of structural measurements. the vfz is subdivided into the ne vinodol fault zone (nevfz), which is coloured with a blueish polygon, and the sw vinodol fault zone (swvfz) coloured with a reddish polygon. g eologia c roatica palenik et al.: geological and structural setting of the vinodol valley (nw adriatic, croatia): insights into its tectonic evolution based on structural investigations 185 allmendinger, 1990) as well as derived synthetic structural focal mechanisms, indicated that the observed palaeostress compressional field is associated with a p-axis predominantly trending ne‒sw, whereas the t-axis is subvertical, steeply dipping towards the nnw at an angle of 81° (see table 1 for details). the second group of the observed reverse faults (ne/rf2) within the vfz, along the ne margin of the study area, is generally characterised by two fault group subsets (fig. 5 and table 1). the first subset is characterised by an average ese dip direction and wnw-directed tectonic transport, whereas the second subtable 1. mean geometric properties of the observed fault planes within the vfz, i.e. along the ne and sw margins of the vinodol valley and bakar bay (nevfz and swvfz) with calculated kinematic indicators and parameters. fault planes observed in the vfz zone were delineated with respect to their geometrical properties and kinematic compatibility within the following groups (see fig. 5): vfz/rf1 – reverse fault group 1; ne/rf2 – reverse faults group; sw/rf3 – reverse faults group 3; vfz/ssf1 strike-slip faults group 1; e) ne/ssf2 – strike-slip faults group 2; sw/ssf3 – strike-slip faults group 3; g) vfz/nf1 – normal faults group 1; ne/nf2 – normal faults group 2; sw/nf3 – normal faults group 3.fault types: r – reverse; ss – strike-slip; n – normal. orientation of the p and t-axis are based on constructed synthetic structural beach-ball diagrams. fault group fault group subset no. of fault data dip azimuth (°) dip angle (°) pitch (°) strike (°) fault type striation p-axis t-axis trend (°) plunge (°) trend (°) plunge (°) trend (°) plunge (°) vfz/rf1 vfz/rf1a 12 55 55 67 – r 82 43 222 10 3 81 vfz/rf1b 15 219 63 74 – 216 54 ne/rf2 ne/rf2a 5 106 60 90 – r 106 60 121 12 250 80 ne/rf2b 3 323 63 60 – 200 47 sw/rf3 sw/rf3a 2 270 63 42 – r 202 37 63 02 158 70 sw/rf3b 2 334 52 62 – 297 43 vfz/ssf1 vfz/ssf1a 12 – – 12 44–224 s-s 111 11 175 11 266 05 vfz/ssf1b 11 – – 10 136–316 268 9 ne/ssf2 ne/ssf2a 3 – – 32 42–222 s-s 124 32 221 06 131 04 ne/ssf2b 8 – – 0 131–311 112 0 sw/ssf3 sw/ssf3a 13 – – 13 76–256 s-s 144 12 018 03 288 02 sw/ssf3b 8 – – 16 168–348 185 25 vfz/nf1 vfz/nf1a 5 78 79 70 – n 135 64 338 77 234 03 vfz/nf1b 11 230 63 75 – 229 55 ne/nf2 ne/nf2a 2 93 51 90 – n 93 51 193 68 79 09 ne/nf2b 2 286 42 35 – 223 23 sw/nf3 sw/nf3a 3 149 69 58 – n 208 51 246 76 339 01 sw/nf3b 3 317 67 55 – 258 48 figure 5. structural diagrams for the vinodol fault zone (vfz), i.e. the ne and sw margins of the vinodol valley and bakar bay (nevfz and swvfz – see fig. 4). the white quadrants on the structural beach-ball diagrams represent compression, while the shaded quadrants represent tension. a) reverse fault group 1 (vfz/rf1); b) reverse fault group 2 (ne/rf2); c) reverse fault group 3 (sw/rf3); d) strike-slip fault group 1 (vfz/ssf1); e) strike-slip fault group 2 (ne/ssf2); f) strike-slip fault group 3 (sw/ssf3); g) normal fault group 1 (vfz/nf1); h) normal fault group 2 (ne/nf2); i) normal fault group 3 (sw/nf3). the red dots, rectangles, and blue triangles indicate σ1, σ2 and σ3, respectively. g eo lo gi a c ro at ic a geologia croatica 72/3186 set is characterised with an average nw dip direction and sedirected tectonic transport. for this group of reverse faults (ne/ rf2), structural analysis of the representative palaeostress field indicates a compressional palaeostress field associated with a paxis dominantly trending nw‒se, whereas the t-axis is subvertical, i.e. steeply dipping towards the wsw (fig. 5 and table 1). the third group of the reverse faults (sw/rf3) observed along the sw margin of the study area is represented by data from only four measured fault planes. this fault group is subdivided into two group subsets characterised by w-dipping (e-directed tectonic transport) and nw-dipping (se-directed tectonic transport) fault subsets (fig. 5 and table 1). structural analysis of the representative palaeostress field indicate that the observed fault planes are related to the compressional palaeostress field, associated with the p-axis dominantly trending ne‒sw, whereas the t-axis is dipping towards se (see table 1 for details). besides the reverse fault planes observed along the nevfz and swvfz, 55 strike-slip fault planes (figs. 2, 5 and 9) were measured. the observed strike-slip fault planes were also separated according to their geometric properties and kinematic compatibility into three fault groups and six group subsets i.e., three conjugate fault pairs (vfz/ssf1, ne/ssf2 and sw/ssf3; see fig. 5). fault groups are characterised by steeply dipping geometry, with average dip angles of 65° and 80°, respectively. measured fault planes along the vfz margins were dominantly striking both nw–se and ne–sw (vfz/ssf1 and ne/ssf2; fig. 5 and table 1), while along the sw margin of the vfz third strikeslip fault group resemble a conjugate fault pair with nnw–sse and ene–wsw strike (sw/ssf3; fig. 5 and table 1). mapped strike-slip fault planes were characterised by structural reactivation, with slickenside overgrowths indicating both dextral and sinistral movements (fig. 10). this implies that for a few observed dextral or sinistral fault surfaces, in addition to the predominant movements they were characterised also by very poorly visible indicators of opposite movement that may indicate occasional interchange of principal stress axes σ1 and σ3 within the same stress field. kinematic analysis of the observed strike-slip fault planes also supports the concept of structural reactivation, indicating that the identified fault planes may have been formed within two slightly different palaeostress fields: the first one associated with the n–s trending p-axis, and the t-axis trending e–w, and the second one associated with the ne‒sw trending p-axis and a taxis trending nw–se (see fig. 5). field observations and identification of cross-cutting relationships between the mapped reverse and strike-slip faults show that strike-slip fault planes mostly cut across, thereby offsetting reverse fault planes, especially along the swvfz (see geological map in fig. 2). this is particularly noticeable in cases where strike-slip faults (with ne‒sw and ene‒ wsw strikes) are actually oriented perpendicular or at an oblique angle to the reverse faults of the nw‒se strike (see geological map in fig. 2), suggesting that the observed strike-slip fault plane systems are probably younger than the reverse ones. along the ne margin of the vfz, eight normal fault planes were measured, whereas along its sw margin 18 normal fault planes were observed. along the ne margin of the vinodol valley, normal fault planes were predominantly identified in its se part, and less in the nw and central parts. measured normal fault planes within the vfz characterised by both pure dip-slip and some oblique slip motions could be separated into three fault groups; vfz/nf1, ne/nf2 and sw/nf3 and six subsets, i.e. three conjugate fault pairs (fig. 5 and table 1). figure 6. photograph of the reverse fault plane (fp=37/48) in recrystallized limestones of the upper cretaceous gornji humac fm. along the ne margin of the vinodol valley. location: 45°13’22.4’’n, 14°42’14.5’’e. figure 7. photograph of the reverse fault plane (fp=24/62) in the recrystallized limestones of the gornji humac fm. along the ne margin of the vinodol valley. location: 45°16’15.5’’n, 14°36’14.2’’e. figure 8. photograph of the reverse fault plane (fp=72/58) in the upper cretaceous milna fm. near the thrust contact with palaeogene clastic deposits covered with the quaternary rockfall and deluvial–proluvial deposits. location: 45°15’32.1’’n, 14°37’7.8’’e. g eologia c roatica palenik et al.: geological and structural setting of the vinodol valley (nw adriatic, croatia): insights into its tectonic evolution based on structural investigations 187 group 1 (vfz/nf1; fig. 5) is characterised by predominantly nw‒se striking fault plane subsets that are steeply dipping towards both ne and sw (fig. 11 and table 1). kinematic analysis shows that these normal fault planes were formed within the palaeostress field characterised by a subvertical p-axis steeply dipping towards the wsw (p-axis orientation is 338/77; table 1) and subhorizontal t-axis trending ne‒sw (see table 1 for details) that in overall resulted in the ne–sw directed extension. the group 2 and group subsets of the normal fault planes (ne/nf2; table 1) observed along the ne margin of the vfz are characterised by a general n‒s strike (locally nne‒ssw or nnw‒sse), dipping to the w (wsw) and e with a dip angle of approx. 40–50° (see table 1). kinematic analysis of collected structural data indicated that these fault planes were formed within the palaeostress field associated with the subvertical paxis (orientation of p-axis is 193/68; see table 1), and t-axis trending ene‒wsw (see table 1 for details), resulting in the ne–sw and e–w extension. due to poor outcrops resulting in ambiguous structural relationships between the cretaceous and palaeogene units, identification of the cross-cutting relationships between the observed normal fault planes and reverse and strikeslip fault planes was rather unclear. large bodies of the quaternary rockfall material and gravitational slides in the vicinity of measured normal fault planes suggest their potential genetic connection. the group 3 and group subsets of the normal fault planes (sw/nf3; table 1) were observed along the vfz sw margin (fig. 5). these conjugate fault pairs are characterised by the ne‒ sw striking fault plane subsets (figs. 5 and 11) dipping both tofigure 9. a) photograph of the fault plane with nw–se orientation (fp=55/81) mapped along the sw margin of the vinodol valley; the fault is probably formed in the palaeostress field with the p-axis trending ne–sw, and t-axis trending nw–se, and subsequently reactivated as a dextral fault within the palaeostress field characterised by the n–s trending p-axis, and e–w oriented t-axis. b) detail of the fault plane – subhorizontal striations indicate dextral movement. recrystallized limestones of the upper cretaceous gornji humac fm. location: 45°11’27.4’’n, 14°42’4.9’’e. orientation of bedding is 30/33. figure 10. photograph of the strike-slip fault plane (fp=54/85) in the recrystallized limestones of the upper cretaceous gornji humac fm. along the sw margin of the vinodol valley. strike-slip fault plane with both dextral and sinistral movement indicators probably represents a reactivated older fault. location: 45°11’27.6’’n, 14°42’4.4’’e. figure 11. photograph of the normal fault plane with the nw–se strike (fp=214/75; ls=80° from nw) within the palaeogene foraminiferal limestones along the sw margin of the vinodol valley. location: 45°9’23.7’’n, 14°44’56.5’’e. g eo lo gi a c ro at ic a geologia croatica 72/3188 wards the nw and se (sw/nf2) (see diagrams in fig. 5). the ne–sw strike is normal to the general strike of the dinarides (nw‒se; fig. 5). these normal fault planes were formed within the palaeostress field with a subvertical p-axis steeply dipping towards the sw, whereas the subhorizontal t-axis trends nw‒se (see table 1 for details). such a palaeostress field resulted in the nw–se directed extension. 4. discussion the results of the geological and structural investigations in the vinodol valley and bakar bay area indicate the complex tectogenesis of this area through the palaeogene, neogene and quaternary, which led to the formation of the recent geological structure of the area. 4.1. geology and palaeogeography of the vinodol valley and bakar bay the nw adriatic domain, including the study area, represents part of the mesozoic adriatic carbonate platform (adcp), and its late cretaceous dynamics was caused by the continuous convergence of the adria microplate and european plate (see środoń et al., 2018 and references therein). changes in the tectonically controlled subsidence between different blocks resulted in the thickness variation of the units, but their general characteristics can be more or less correlated over significant distances across the adcp (vlahović et al., 2005). the lower part of the oldest upper cretaceous unit, the cenomanian milna fm., does not crop out in the study area, and therefore its estimated thickness of more than 250 m corresponds well with the >320 m thick succession determined for the entire unit in northern istria (velić & vlahović, 1994), 300–400 m in nw slovenia (jurkovšek et al., 1996), more than 400 m of shallow-marine cenomanian deposits on the island of cres (fuček et al., 2015), 300–350 m on the island of unije (fuček et al., 2015), 300–350 m on the island of vis (korbar et al., 2012) and c. 400 m thick cenomanian shallow-marine limestones of the milna fm. determined on the island of brač (gušić & jelaska, 1990). the thickness of overlying limestones with pelagic influence of the sv. duh fm., deposited during a regional temporary drowning event near the cenomanian/turonian boundary was estimated at 130–150 m in the study area and also fits with thicknesses determined in other areas: 110–140 m in northern istria (ćićarija – brčić et al., 2017), 70–200 m in nw slovenia (jurkovšek et al., 1996), 30–100 m on the island of cres (fuček et al., 2015), 40 m on the island of vis (korbar et al., 2012) or c. 110 m at the locus typicus of the unit, on the island of brač (gušić & jelaska, 1990). the youngest cretaceous rocks belonging to the gornji humac fm. are exclusively of turonian age in the study area, since regional emergence between the cretaceous and palaeogene (recorded in almost all parts of the adriatic carbonate platform) in this area started relatively early, probably during the late turonian (c. 90 ma), a bit later than in neighbouring n istria (matičec et al., 1996), the n part of the island of cres and the island of krk (ćosović et al., 1994), as well as in the lower, autochthonous part of the učka mt. such early emergence in the study area provides additional evidence that the area in the central nw part of the adcp uplifted before the end-turonian was relatively large, probably covering several thousand km2 (stretching from w and nw istria to krk and the vinodol area). deposits of the gornji humac fm. are consequently in the vinodol valley relatively thin, from 70 to c. 100 m (the variable thickness is due to intense karstification during the relatively long stratigraphic hiatus, probably 35 to 40 my). the top of the gornji humac fm. is in other areas of the adriatic carbonate platform usually much younger, mostly upper santonian or even campanian in age, resulting consequently in much thicker deposits – e.g. from 250 to almost 500 m at their type locality on the island of brač (gušić & jelaska, 1990). the estimated thickness of palaeogene foraminiferal limestones of c. 200 m is thicker than the average thickness of these deposits presented on the crikvenica sheet of the basic geological map (120 m, šušnjar et al., 1970). however, the thickness of foraminiferal limestones is locally very variable, depending on the palaeorelief, local subsidence and duration of the stratigraphic hiatus – e.g. in the čikola river section španiček et al. (2017) determined their thickness of 255 m, and drobne et al. (1991) measured thicknesses between 230 and 280 m in the ravni kotari area. the thickness of the transitional deposits (td) in the vinodol valley was estimated at 60 m, and thickness of overlying flysch deposits (fd) at >350 m, which is significantly greater than the average values presented on the crikvenica sheet of the basic geological map (the thickness of both units was estimated at 200 m – šušnjar et al., 1970), but much less than the average thicknesses represented on neighbouring maps (labin: td 300–700, fd 450 m – šikić et al., 1969; ilirska bistrica: td 200 m, fd 400–650 m – šikić et al., 1972; rab: td 150 m, fd 600 m – mamužić et al., 1969). 4.2. structural relationships in the vinodol valley and bakar bay structural investigations in the vinodol valley and its nw prolongation bakar bay based on structural data collected on fault planes within the nevfz and swvfz (fig. 5) resulted in more than 120 measurements at 127 stations. these structural data were mostly collected along the tectonic contact between the upper cretaceous limestones and the eocene carbonate and clastic deposits and provided field evidence of the tectonic evolution of the study area, which may be also used in understanding the quaternary evolution of the vinodol valley area. kinematic analysis of fault planes and the overlapping relationships identified in the study area provided not only basic information of palaeostress field changes recorded along the mapped fault systems but also their potential neotectonic activity in respect to the recent stress field. in the area of the vinodol valley and bakar bay the first fault group (vfz/rf1) is represented by the reverse fault planes observed along both margins, which are characterised by striations of both pure dip-slip and oblique-slip kinematics (fig. 5, see diagram a). kinematic analysis shows that the first reverse fault group (vfz/rf1) was characterised by steep conjugate fault planes (c. 55° and 63°) dipping towards the ne and sw, indicating swand ne-directed tectonic transport respectively (fig. 5, diagram a; see table 1 for details). with the nw‒se strike, reverse fault group subsets, i.e. conjugate fault pairs along the ne margin show dominant sw-directed tectonic transport, while the structural position of the lithostratigraphic units (fig. 3) and measured fault planes along the main thrusting fault zone along the sw margin of the vinodol valley suggest predominant nedirected tectonic transport (see cross-sections in the fig. 3). the second reverse fault plane group (ne/rf2) observed along the ne margin of the vfz was characterised by conjugate fault planes with a general ne–sw strike, dipping towards the nw and se (c. 60° and 63°), indicating nwand se-directed g eologia c roatica palenik et al.: geological and structural setting of the vinodol valley (nw adriatic, croatia): insights into its tectonic evolution based on structural investigations 189 tectonic transport (fig. 5, diagram b; see table 1 for details). the third fault plane group (sw/rf3) of reverse faults along the sw margin of the vinodol valley and bakar bay resemble the reverse fault plane group ne/rf2 observed along the ne margin. the sw/rf3 fault group is characterised by subsets dipping generally towards the nw (w) and ese (c. 63° and 52°), with the tectonic transport towards se (e) and wnw, respectively (diagram c in fig. 5; see table 1 for details). palaeostress field analysis of measured reverse fault planes along the thrust contact of the upper cretaceous and palaeogene carbonates (foraminiferal limestones) over the younger palaeogene clastic deposits suggest the compressional stress field and structures formed within both ne‒sw trending and nw‒se trending compression (diagrams a, b and c in fig. 5; see table 1 for details). structures related to the ne‒sw trending compression probably correlate with the principal ‘dinaridic tectonic phase’ (sensu blašković, 2005 and references therein), which during the late cretaceous and palaeogene resulted in the build up of the major fault and fold related nw‒se striking structures in the dinarides, being characterised by ne-dipping geometry and sw-directed tectonic transport (prelogović et al., 1981, 1982, 1995; blašković, 2005; žibret & vrabec, 2016). though typical nw‒se striking, ne-dipping structures were previously observed within the vinodol valley and bakar bay (blašković, 1991, 1997, 1999, 2005; prelogović et al., 1981, 1982, 1995), this study identified numerous fault planes within the vfz that are steeply dipping (c. 60°) towards the sw and are characterised by ne-directed tectonic transport. these new findings confirm that during the tectonic evolution of the external dinarides, structures with ne-directed tectonic transport have been formed in some areas (as in the neighbouring velebit mt. area – vlahović et al., 2012; środoń et al., 2018; tomljenović et al., 2018) along with the predominant swdirected tectonic transport. such structures were formed either concurrently with sw-vergent dinaridic structures or their formation may present a substage within the principal dinaridic tectonic phase. the second observed reverse fault plane group in this work characterised by nw (w) and ne, ese dip directions (diagrams b and c in fig. 5; see table 1 for details) correlates with results reported by blašković (1998). in reported study author described existing dinaridic structures as refolded and faulted structures which were deformed during the ‘late dinaridic phase’ as a result of the regional stress field change from ne‒sw trending compression to wnw–ese trending compression beside the measured reverse fault planes in the area of the vinodol valley and bakar bay numerous strike-slip fault planes were also observed in this study. in accordance with the geometric properties and kinematics within the vinodol fault zone delineated strike-slip fault groups were characterised by subvertical geometry and slickensides showing structural reactivation, i.e., both dextral and sinistral motions. characterised by the nw‒se strike (dipping towards both ne and sw) and perpendicular strike ne‒sw (dipping towards both nw and se), kinematic analysis of the observed strike-slip fault planes indicated a similar palaeostress field to the observed reverse fault plane groups, being characterised by n–s, ne‒sw, and nne‒ssw trending p-axis (diagrams d, e, and f in fig. 5; see table 1 for details). these results may suggest that at least some of observed strikeslip fault planes in the study area resemble structurally reactivated inherited reverse fault planes within the transpressional/ transtensional stress field. however, at the same time, due to their subvertical geometry and present field observations of cross-cutting relationships between mapped reverse and strike-slip fault planes, we believe that the observed strike-slip fault planes in the study area are probably younger than the reverse faults because most of them cross-cut and laterally displace measured reverse fault planes (fig. 3). at the same time, the geometry of mapped strike-slip faults and computed stress field characterised by n–s, ne‒sw, and nne‒ ssw trending p-axis is in accordance with the observed strikeslip and reverse fault planes in the nw external dinarides of slovenia, where n–s oriented compression during the pliocene and quaternary has also been indicated (žibret & vrabec, 2016). according to prelogović et al. (1981, 1982, 1995), the mapped nw‒se and ne‒sw striking strike-slip faults in the vinodol valley and bakar bay are parts of the ilirska bistrica– rijeka–senj seismogenic fault zone and resemble neotectonically active faults in the study area. mapped normal faults in the vinodol valley and bakar bay were characterised by nw‒se and ne‒sw (locally n–s, nne‒ ssw and nnw‒sse) striking planes that accommodated pure dip-slip/oblique motions (diagrams g, h and i in fig. 5; see table 1) and ne‒sw and nw‒se (locally e‒w) trending extension. though the structural relationships between reverse and strikeslip fault groups with respect to the normal faults are not clear, it can be assumed that ne‒sw, e‒w and nw‒se directed extension may be considered as a local feature associated with gravitational collapse of the hanging wall structural sequence, i.e. hinge zones of the hosting anticlines. in our opinion, such gravitationally conditioned extension (cf. tavani et al., 2012 and references therein) may be either potentially concurrent to active folding and formation of the vinodol valley and bakar bay area during the late cretaceous and palaeogene or it was associated with the younger tectonic phase characterised by radial extension of the folded structure after/before compressional/transpressional tectonics which commenced in the pliocene and quaternary. according to van unen et al. (2019) and their observations in the area of the internal dinarides, the extension of folded structures in the dinarides occurred during the late cretaceous–oligocene, simultaneously or slightly after the main orogeny build up, but definitely before the pliocene–quaternary transpression. furthermore, in the vicinity of the observed normal fault planes, large bodies of quaternary rockfall material and gravitational slides have been mapped, which according to blašković (1997) may suggest their potential role in the increasing rock instability and failure. results of the structural study conducted and presented in this paper are generally in accord with the existing knowledge on the local/regional tectonic evolution in this part of the external dinarides (prelogović et al., 1981, 1982, 1995; blašković, 2005; žibret & vrabec, 2016; van unen et al., 2019). however, our structural results address the presence of compressional structures characterised by both sw and ne-directed tectonic transport. our field observations of the cross-cutting relationships between mapped reverse and strike-slip fault planes also suggest that the observed strike-slip fault planes in the study area are probably younger than the reverse fault planes. alternatively, the measured normal fault planes may be associated with gravitational collapse within the hinge zones of the hosting anticlines during the late cretaceous–oligocene, simultaneously or slightly after orogeny build up, however, before the pliocene– quaternary transpression. g eo lo gi a c ro at ic a geologia croatica 72/3190 4.3. comparison of palaeostress field analysis and seismological data in order to address the potential neotectonic activity of faults within the vfz and their possible favourable orientation within the recent stress field, we hereby compare our results of palaeostress field analysis with the available seismological data from the wider study area. the ongoing tectonic activity in the greater vinodol area (including the epicentral areas of ilirska bistrica–klana, rijeka, bakar, vinodol, krk and senj) is expressed by moderate seismicity, with hypocentres in the upper crust, mostly shallower than 20 km. it is well documented in the corresponding entries in the croatian earthquake catalogue (cec, first described by herak et al., 1996, updated annually thereafter) and by numerous seismicity-related studies (e.g. markušić & herak, 1999; ivančić et al., 2006, 2018; kastelic et al., 2013; herak & herak, 2017 and references therein). figure 12 shows that significant earthquakes are known to have occurred here in the past. the most important ones (from the point of view of this study) are the events of 1323, 1750, 1870, and 1916. the strongest of them could have been that of 1323 (the ‘vinodol earthquake’) which is often listed as causing intensity as high as ix° msk. although this earthquake probably indeed occurred and caused considerable damage, it is unfortunate that only very sparse information exists about it (merely a sentence in the glagolitic document from grižane), so we treat both the location and the magnitude as unreliable. the large bakar earthquake of november 28, 1750 (io = vii–viii msk) has been studied in detail by herak et al. (2017), so here we will only mention the fact that about 3000 aftershocks were felt in the three years following it. the klana mainshock of 1870 (march 1, 1870, io = viii msk, herak et al., 2018) was the last significant earthquake in the ilirska bistrica–klana area. it is still vividly remembered by the local inhabitants, and is one of key events for understanding seismic hazard in the greater rijeka area. the most recent one occurred on march 12, 1916 about 10 km east of novi vinodolski, with the epicentral intensity io = viii msk. most damage was reported from grižane (over 100 houses damaged) and bribir (in the ene part of the vinodol valley, within the ne vinodol fault zone (nevfz) area ‒ see fig. 4). contemporary seismicity follows the same pattern (fig. 13), however, with no event exceeding magnitude 4.8 for over two decades. nevertheless, significant densification of the network of seismological stations in croatia and slovenia in this time period, enabled lowering the detection threshold well below magnitude 1.0 in some areas. this, in turn, made it possible to collect information on details of seismogenic faults properties even during their periods of low activity. in particular, the observed spatial distribution of the first p-wave polarity could have been inverted for a number of rather small events (fig. 13), and advanced location methods (e.g. herak & herak, 2017) were used to learn more about the geometry of active faults. focal mechanism solutions (fms, shown in fig. 13) have been computed by inverting the observed spatial distribution of figure 12. historical seismicity (1323–1908) and epicentres of instrumentally recorded earthquakes (until 1995) with magnitudes ml > 4.5 in the wider vinodol region. the year of earthquake occurrence is indicated by each epicentre. the events of 1323, 1648, and 1776 are considered uncertain (see text). magnitudes of the pre-instrumental earthquakes are estimated from the observed intensities. after the croatian earthquake catalogue (first described by herak et al., 1996, updated annually thereafter). g eologia c roatica palenik et al.: geological and structural setting of the vinodol valley (nw adriatic, croatia): insights into its tectonic evolution based on structural investigations 191 the first longitudinal wave polarity for the best fit double-couple source geometry (fms-database, 2019). the p-axes computed from fms are often taken as the first order proxy (within about ±15°) for the direction of local tectonic movement. judging from their spatial distribution as presented in fig. 13, the tectonic stress field is relatively homogeneous and horizontal (average plunge 1.5°), with a mean orientation close to n–s (n13°e). individual deviations from this direction may be a consequence of local stresses, pre-existing weak fractures (especially for small earthquakes), variations in pore pressure, influence of friction during faulting, or simply the inversion uncertainty. the suggested types of faulting, on the other hand, are far from homogeneous over the study region. while in the nw part of the considered area (in slovenia) all fms are consistent with right-lateral strike-slip faulting along the se–nw striking subvertical faults (e.g. the raša fault), further to the se there is a mixture of transpressive, almost pure dip-slip, and strike-slip faulting. in a compressional tectonic setting this is indicative of a generally transpressive regime, where the σ2 and σ3 principal stresses are of similar magnitude, and often only details determine which one is vertical. indeed, our study area (and the greater kvarner‒velebit region) may be regarded as the transitional zone of transpression where predominantly reverse and thrust mechanisms of the southern external dinarides gradually switch into pure strike-slip in the nw dinarides of southern slovenia. in such environments, instead of oblique faulting, the stress release may also be decoupled between parallel striking thrust and strike-slip faults. according to michael (1990), assuming equality of resistance to sliding on both faults and the angle of convergence between 50° and 35° (as is the case here), decoupled faulting will be preferred over oblique faulting for thrusts with dip angles lower than 20–30°. beck’s (1983) estimates are more permissive and favour decoupling even for steeper dipping faults. this process may be plausible in some cases here, especially for focal depths exceeding about 5 km or if the strike-slip fault is considerably weaker than the thrust. synthetic focal mechanisms constructed by applying the right dihedra method (angelier & mechler, 1977) (see fig. 5) show good correspondence with the available focal mechanism solutions (fig. 13). both synthetic focal mechanism and available focal mechanism solutions for instrumentally recorded earthquakes within the larger rijeka‒vinodol area and kvarner bay suggest that the principal nw‒se and ne‒sw striking seismogenic sources (defined by mapping as reverse and strike-slip faults) are compressional and transpressional structures, which are recently tectonically active within the compressional stress field, characterised by a generally n‒s oriented p-axis. 5. conclusions in the area of the vinodol valley and bakar bay geological and structural investigations highlight the complex tectonic evolution of this area not only through the palaeogene and neogene, but also during the quaternary period. upper cretaceous informal lithostratigraphic units mapped in the study area can be well correlated with units proposed by figure 13. seismicity in the period 1996–2017 (ml > 0.0). the hypocentral depth is represented by the symbol colour according to the colour scale on the right. only events located by at least 8 reported phase onsets, and having azimuthal gap of reporting stations smaller than 120° are shown. the beach-ball diagrams (1986–2017) represent focal mechanism solutions (fms) as lower hemisphere, stereographic projection of the sense of the p-wave first motion onto the focal sphere (compressive quadrants are shaded). see the legend for colour-coding of the mechanism type. red lines show inferred orientation of the p-axes for each fms. g eo lo gi a c ro at ic a geologia croatica 72/3192 gušić & jelaska (1990), except for the much shorter stratigraphic range of the youngest unit, the gornji humac fm. upper turonian age of the youngest cretaceous rocks in the vinodol valley suggest that the uplifted area in the central nw part of the adriatic carbonate platform at the end of turonian already covered several thousands km2 (from w and nw istria to the krk and vinodol area). results of the structural investigation in general correspond to those of previous studies and existing knowledge about the tectonic evolution of the dinarides, including several important new findings. in the area of the vinodol valley and bakar bay, the majority of the observed reverse fault planes were characterised by both pure dip-slip and oblique-slip kinematics. kinematic analysis shows that the first reverse fault groups were characterised by steep planes (c. 60°) dipping either towards the ne or the sw indicating swand ne-directed tectonic transport respectively. the ne-directed tectonic transport was determined along mapped structures within both the ne and sw margins of the vinodol valley. however, according to the structural and stratigraphic relationships of the mapped lithostratigraphic units along the sw margin of the vinodol valley we address faulted structures as predominantly ne-vergent structures. both ne and sw dipping structures are related to a ne‒sw trending compression stress field that probably formed within the dinaridic tectonic phase (blašković 2005; žibret & vrabec, 2016). newly mapped sw-dipping structures indicate that beside the predominant sw-vergent structures in the dinarides, ne-vergent structures formed either concurrent to the sw-vergent structures or were associated with a separate sub-stage within the principal dinaridic phase that also existed in the study area. the second mapped reverse fault plane groups in the study area are characterised by both nw (w) and ese dip directions, and se (e) and wnw directed tectonic transport respectively. these fault plane subsets resemble conjugate fault pairs formed within both ne‒sw and nw‒se trending compression. according to blašković (1998) these dinaridic structures were formed in the ‘late dinaridic phase’ of the refolding and faulting of existing dinaridic structures due to a change in regional stress field from ne‒sw trending compression to wnw–ese trending compression. in the area of the vinodol valley and bakar bay, strike-slip fault planes were also observed. strike-slip fault groups characterised by subvertical geometry show structural reactivation, i.e. both dextral and sinistral motions. nw‒se striking (dipping both towards ne and sw) and ne‒sw striking fault planes indicate a palaeostress field characterised by ne‒sw, n‒s and a nnw‒ sse trending p-axis, similar to the observed reverse fault planes. orientation of the p-axis associated with the transpressional/transtensional stress field may suggest that mapped strike-slip fault planes in the study area resemble structurally reactivated older reverse fault planes. at the same time, the fault subvertical geometry and cross-cutting relationships between mapped reverse and strike-slip fault planes suggests that the strike-slip structures are probably the younger ones. measured normal fault planes in the study area characterised by generally nw‒se and ne‒sw striking planes (ne‒sw and nw‒se directed extension) and may have been caused by gravitational collapse of hanging wall structures in the hinge zones of the anticline (tavani et al., 2012 and references therein) during the orogen build up (van unen et al., 2019) or slightly after, however before the pliocene–quaternary transpression with dominant strike-slip motions. comparison of palaeostress field analysis and constructed synthetic focal mechanism with available data on focal mechanism solutions within the ilirska bistrica–rijeka–senj seismogenic fault zone shows the favourable orientation of observed nw‒se and ne‒sw striking faults with respect to recent compressional/transpressional stress field (n‒s oriented p-axis) suggesting they may be potential seismogenic sources within the study area. acknowledgement this paper resulted from work on two scientific projects funded by the croatian science foundation (hrzz): velebit (grant no. ip-2014-09-9666, pi professor marijan herak) and geosekva (grant no. ip-2016-06-1854, pi dr. tvrtko korbar), and the authors are grateful for all support in the field and cabinet research. the authors would like to thank dr. ana mladenović (university of belgrade) and professor marko vrabec (university of ljubljana) for their very constructive remarks and comments that considerably improved the quality of this manuscript. we would like to thank colleagues nenad oštrić and dr. tvrtko korbar from the croatian geological survey (cgs), who were part of the vinodol valley area geological mapping team. we would also like to thank dr. georg koch (cgs) for useful advice and dr. ajka šorša (cgs) for preparation of the vinodol valley geological map. references angelier, j. & mechler p. (1977): sur une méthode graphique de recherche des contraintes principales également utilisable en tectonique et en séismologie: la méthode des dièdres droits.‒ bull. soc. géol. france, 19, 1309‒1318. doi:10.2113/ gssgfbull.s7-xix.6.1309 beck, m.e. jr. (1983): on the mechanism of tectonic transport in zones of oblique subduction.– tectonophysics, 93, 1‒11. doi: 10.1016/0040-1951(83)90230-5 blašković, i. (1991): raspored uzdužnih, reverznih i normalnih rasjeda i konstrukcija oblika i dubina plohe podvlačenja (disposition of the longitudinal, reverse and normal faults and the construction of the forms and depth of the underthrusting surfaces).‒ geol. vjesnik, 44, 247‒256, zagreb. blašković, i. (1997): the helicoidal fault systems of vinodol (croatia) and their genesis.‒ geol. croatica, 50/1, 49‒56, zagreb. blašković, i. (1998): the two stages of structural formation of the costal belt of the external dinarides.‒ geol. croatica, 51/1, 75‒89, zagreb. blašković, i. (1999): tectonics of part of the vinodol valley within the model of the continental crust subduction.‒ geol. croatica, 52/2, 153‒189, zagreb. blašković, i. (2005): geologija vinodola (geology of vinodol).‒ in: biondić, r., vlahović, i. & velić, i. (eds.): 3. hrvatski geološki kongres (third croatian geological congress), vodič ekskurzija (excursion guide-book), 39‒48, zagreb. brčić, v., glumac, b., fuček, l., grizelj, a., horvat, m., posilović, h. & mišur, i. (2017): the cenomanian–turonian boundary in the northwestern part of the adriatic carbonate platform (ćićarija mtn., istria, croatia): characteristics and implications.‒ facies, 63:17. doi: 10.1007/s10347-017-0499-7 ćosović, v., balončić, d., koić, m., marjanac, t., moro, a., gušić, i. & jelaska, v. (1994): paleontological evidence of paleogene transgression on adriatic carbonate platform.‒ géologie méditerranéenne, 21/3–4, 49–53. doi: 10.3406/geolm.1994.1524 drobne, k., vlahović, i., trutin, m., pavlovec, r., ćosović, v., babac, d., cimerman, f., lučić, d. & pavšič, j. (1991): excursion b – ravni kotari, paleogene.– in: vlahović, i. & velić, i. (eds.): some aspects of the shallow water sedimentation on the adriatic carbonate platform (permian to eocene), excursion guide–book, the second international symposium on the adriatic carbonate platform – relations with adjacent regions, 51–105, zagreb. fms-database (2019): database of focal mechanism solutions.– archives of the department of geophysics, faculty of science, university of zagreb. fuček, l., matičec, d., vlahović, i., oštrić, n., prtoljan, b., korolija, b., korbar, t., husinec, a. & palenik, d. (2015): osnovna geološka karta republike hrvatske mjerila 1:50.000 – list cres i lošinj [basic geological map of the republic of the croatia 1:50,000 scale – cres and lošinj sheet – in croatian].‒ hrvatski geološki institut, zavod za geologiju. isbn: 978-953-690753-3, zagreb. grimani, i., šušnjar, m., bukovac, j., milan, a., crnolatac, i., šikić, d. & blašković, i. (1973): osnovna geološka karta sfrj 1:100.000. tumač za list crikvenica l33‒102 [basic geological map of the sfry 1:100,000; geolg eologia c roatica palenik et al.: geological and structural setting of the vinodol valley (nw adriatic, croatia): insights into its tectonic evolution based on structural investigations 193 ogy of the crikvenica sheet – in croatian].‒ institut za geološka istraživanja zagreb (1963), savezni geološki zavod, beograd, 47 p. gušić, i. & jelaska, v. (1990): stratigrafija gornjokrednih naslaga otoka brača u okviru geodinamske evolucije jadranske karbonatne platforme (upper cretaceous stratigraphy of the island of the brač).‒ jugosl. akad. znan. i umjet., institut za geološka istraživanja, oour za geologiju, str. 160, zagreb. haq, b.u., hardenbol, j. & vail, p.r. (1987): chronology of fluctuating sea levels since the triassic.‒ science, 235, 1156‒1167. doi: 10.1126/science.235.4793.1156 hardenbol, j., thierry, j., farley, m.b., jacquin, t., de graciansky, p.c. & vail, p. (1998): mesozoic and cenozoic sequence chronostratigraphic framework of european basins.– in: graciansky, p.c. et al. (eds.): mesozoic and cenozoic sequence stratigraphy of european basins, sepm special pub., 60, 3–13, charts 1–8. doi: 10.2110/pec.98.02.0003 herak, m. & herak, d. (2017): seismicity and seismic sources in the greater kvarner‒velebit area, croatia: recent advances.‒ in: 5th regional scientific meeting on quaternary geology dedicated to geohazards – abstracts, zagreb, 20‒21. herak, m., herak, d. & markušić, s. (1996): revision of the earthquake catalogue and seismicity of croatia, 1908‒1992.‒ terra nova, 8, 86‒94. herak, d., sović, i., cecić, i., živčić, m., dasović, i. & herak, m. (2017): historical seismicity of the rijeka region (northwest external dinarides, croatia) ‒ part i: earthquakes of 1750, 1838, and 1904 in the bakar epicentral area.‒ seismological research letters, 88/4, 1‒12. doi: 10.1785/0220170014 herak, m., živčić, m., sović, i., cecić, i., dasović, i., stipčević, j. & herak, d. (2018): historical seismicity of the rijeka region (nw external dinarides, croatia) – part ii: the klana earthquakes of 1870.– seismological research letters, 89/4, 1524‒1536. doi:10.1785/0220180064 hgi (2009): geološka karta republike hrvatske, m 1:300.000 [geological map of the republic of croatia, 1:300,000 scale – in croatian].‒ hrvatski geološki institut (croatian geological survey), department of geology, zagreb. ivančić, i., herak, d., markušić, s., sović, i. & herak, m. (2006): seismicity of croatia in the period 2002–2005.‒ geofizika, 23/2, 1‒17. ivančić, i., herak, d., herak, m., allegretti, i., fiket, t., kuk, k., markušić, s., prevolnik, s., sović, i., dasović, i. & stipčević, j. (2018): seismicity of croatia in the period 2006–2015.‒ geofizika, 35/1, 69‒98. doi:10.15233/gfz.2018.35.2 jurkovšek, b., toman, m., ogorelec, b., šribar, l., drobne, k., poljak, m. & šribar, lj. (1996): formacijska geološka karta južneg dela tržaško– komenske planote, kredne in paleogenske karbonatne kamnine 1:50.000 [geological map of the southern part of the trieste–komen plateau. cretaceous and paleogene carbonate rocks 1:50,000 scale – in slovenian].‒ inštitut za geologijo, geotehniko in geofiziko ljubljana, 143 p. kastelic, v., vannoli, p., burrato, p., fracassi, u., tiberti, m.m. & valensise, g. (2013): seismogenic sources in the adriatic domain.‒ mar. petrol. geol., 42, 191–213. doi: 10.1016/j.marpetgeo.2012.08.002 korbar, t., belak, m., fuček, l., husinec, a., oštrić, n., palenik, d. & vlahović, i. (2012): osnovna geološka karta republike hrvatske mjerila 1:50.000 – list vis 3 i biševo 1 [basic geological map of the republic of the croatia 1:50000 scale ‒ vis 3 and biševo 1 sheet – in croatian].– hrvatski geološki institut, zagreb. mamužić, p., milan, a., korolija, b., borović, i. & majcen, ž. (1969): osnovna geološka karta sfrj 1:100.000, list rab l 33‒114 [basic geological map of sfry 1:100,000 scale, rab sheet – in croatian].‒ institut za geološka istraživanja zagreb (1959–1965), savezni geološki zavod beograd. markušić, s. & herak, m. (1999): seismic zoning of croatia.‒ natural hazards, 18, 269‒285. marrett, r. & allmendinger, r.w. (1990): kinematic analysis of fault-slip data.‒ journal of structural geology, 12, 973–986. doi:10.1016/0191-8141(90)90093-e matičec, d., vlahović, i., velić, i. & tišljar, j. (1996): eocene limestones overlying lower cretaceous deposits of western istria (croatia): did some parts of present istria form land during the cretaceous?– geologia croatica, 49/1, 117– 127. michael, a.j. (1990): energy constraints on kinematic models of oblique faulting: loma prieta versus parkfield-coalinga.‒ geophysical research letters, 17/9, 1453‒1456. doi: 10.1029/gl017i009p01453 mikes, t., báldi-beke, m., kázmér, m., dunkl, i., & von eynatten, h. (2008): calcareous nannofossil age constraints on miocene flysch sedimentation in the outer dinarides (slovenia, croatia, bosnia-herzegovina and montenegro).‒ in: siegesmund, s., fügenschuh. b. & froitzheim, n. (eds.): tectonic aspects of the alpine‒dinaride‒carpathian system. geol. soc. london, spec. publ. 298, 335‒363. doi: 10.1144/sp298.16 ortner, h., reiter, f. & acs, p. (2002): easy handling of tectonic data: the programs tectonicvb for mac and tectonics fp forwindowstm.‒ computers and geosciences, 28, 1193–1200. prelogović, e., blašković, i., cvijanović, d., skoko, d. & aljinović, b. (1981): seizmotektonske značajke vinodolskog područja (seismotectonic characteristics of the vinodol area).‒ geol. vjesnik, 33, 75‒93, zagreb. prelogović, e., cvijanović, d., aljinović, b., kranjec, v., skoko, d., blašković, i. & zagorac, ž. (1982): seizmotektonska aktivnost duž priobalnog dijela jugoslavije (seismotectonic activity along the coastal area of yugoslavia).‒ geol. vjesnik, 35, 195‒207, zagreb. prelogović, e., kuk, v., jamičić, d., aljinović, b. & marić, k. (1995): seizmotektonska aktivnost kvarnerskog područja (seismotectonic activity of kvarner area).‒ in: vlahović, i., velić, i. & šparica, m. (eds.): 1. hrvatski geološki kongres (first croatian geological congress), zbornik radova 2 (proceeding 2), 487‒490, zagreb. schlanger, s.o. & jenkyns, h.c. (1976): cretaceous anoxic events: causes and consequences.– geologie en mijnbouw, 55/3–4, 179–184. środoń, j., anczkiewicz, a.a., dunkl, i., vlahović, i., velić, i., tomljenović, b., kawiak, t., banaś, m. & von eynatten, h. (2018): thermal history of the central part of the karst dinarides, croatia: combined application of clay mineralogy and low-t thermochronology.– tectonophysics, 744, 155–176. doi: 10.1016/j.tecto.2018.06.016 šikić, d., polšak, a. & magaš, n. (1969): osnovna geološka karta sfrj 1:100.000, list crikvenica l 33‒101 [basic geological map of sfry 1:100,000 scale, geology of the crikvenica sheet – in croatian].‒ institut za geološka istraživanja zagreb (1958–1967), savezni geološki zavod, beograd. šikić, d., pleničar, m. & šparica, m. (1972): osnovna geološka karta sfrj 1:100.000, list ilirska bistrica l 33‒89 [basic geological map of sfry 1:100,000 scale, geology of the ilirska bistrica sheet – in croatian].‒ institut za geološka istraživanja zagreb (1958–1967), savezni geološki zavod, beograd. španiček, j., ćosović,v., mrinjek, e. & vlahović, i. (2017): early eocene evolution of carbonate depositional environments recorded in the čikola canyon (north dalmatian foreland basin, croatia).– geologia croatica, 70/1, 11–25. doi: 10.4154/gc.2017.05 šparica, m., koch, g., ibrahimpašić, h., galović, i. & bergant, s. (2005): novi prinosi stratigrafiji paleogenskih klastično‒karbonatnih naslaga jugoistočnog dijela istre, hrvatska (new contributions to stratigraphy of paleogene clastic‒carbonate deposits from southeastern istria, croatia).‒ in: velić, i., vlahović, i. & biondić, r. (eds.): 3. hrvatski geološki kongres (third croatian geological congress), knjiga sažetaka (abstracts book), 147‒148, zagreb. šušnjar, m., bukovac, j., nikler, l., crnolatac, i., milan, a., šikić, d., grimani, i., vulić, ž. & blašković, i. (1970): osnovna geološka karta sfrj 1:100.000, list crikvenica l 33‒102 [basic geological map of sfry 1:100,000 scale, geology of the crikvenica sheet – in croatian].‒ institut za geološka istraživanja zagreb (1961–1969), savezni geološki zavod, beograd. tavani, s., storti, f., bausà, j. & muñoz, a. (2012): late thrusting extensional collapse at the mountain front of the northern apennines (italy).– tectonics, 31. tc4019, 1‒17. doi:10.1029/2011tc003059 tomljenović, b., balling, p., matoš, b., vlahović, i., schmid, s., ustaszewski, k., blažok, l., posarić, d. & širol, a. (2018): structural architecture and tectonic evolution of the velebit mt. in the central part of the external dinarides in croatia.– in: neubauer, f., brendel, u. & friedl, g. (eds.): abstracts, advances of geology in southeast european mountain belts. xxi international congress of the carpathian balkan geological association, september 10–13, 2018. geologica balcanica, p. 202. turner, f.j. (1953): nature and dynamic interpretation of deformation lamellae in calcite of three marbles.– american journal of science, 251, 276–298. doi: 10.2475/ajs.251.4.276 van unen, m., matenco, l., nader, f.h., darnault, r., mandić, o. & demir, v. (2019): kinematic of foreland-vergent crustal accretion: inferences from the dinarides evolution.– tectonics, 38/1, 49–76. doi:10.1029/2018tc005066 velić, i. & vlahović, i. (1994): foraminiferal assemblages in the cenomanian of the buzet–savudrija area (northwestern istria, croatia).– geologia croatica, 47/1, 25–43. vlahović, i., korbar, t., moro, a., velić, i., skelton, p.w., fuček, l. & tišljar, j. (2002): latest cenomanian to earliest turonian platform drowning and turonian recovery of shallow–water platform deposition in southern istria.– abstracts and excursion guidebook, sixth international congress on rudists (rovinj, croatia), 123–127. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: paleogeography, main events and depositional dynamics.– palaeogeography, palaeoclimatology, palaeoecology, 220, 333–360. doi: 10.1016/j.palaeo.2005.01.011 vlahović, i., mandic, o., mrinjek, e., bergant, s., ćosović, v., de leeuw, a., enos, p., hrvatović, h., matičec, d., mikša, g., nemec, w., pavelić, d., penciger, v., velić i. & vranjković, a. (2012): marine to continental depositional systems of outer dinarides foreland and intramontane basins (eocene–miocene, croatia and bosnia and herzegovina).– field trip guide, 29th ias meeting of sedimentology, schladming/austria, journal of alpine geology 54, 405–470. žibret, l. & vrabec, m. (2016): paleostress and kinematic evolution of the orogeny-parallel nw–se striking faults in the nw external dinarides of slovenia unraveled by mesoscale fault-slip data analysis.– geologia croatica, 69/3, 295–305. doi: 10.4154/gc.2016.30 obituary professor emeritus ivan jurković (1917-2014)  doi: 10.4154/gc.2015.12 professor jurković was born on 27 march 1917 in ogulin in croatia. he attended elementary school and a gymnasium in zagreb and entered the university of zagreb, technical faculty (department of chemical engineering) in 1935 to study chemistry. he graduated in 1939 but became interested in geology and continued his study at the university of zagreb, faculty of humanities and social sciences (department of geology). he received his phd with a thesis entitled „mineral parageneses from the mid bosnian schist mountains with the special reference to gold-bearing mercuran tetrahedrite“ in 1956 and completed his habilitation in 1957 at the university of zagreb (technical faculty). professor jurković became an assistant in the mineralogical-geological institute of technical faculty at the university of zagreb in 1939, but during the second world war (between 1942 and 1945) he volunteered in this institute under the supervision of professor miroslav tajder. from 1945 professor jurković was employed continuously in the mineralogical-geological institute (today the department for mineralogy, petrology and mineral resources of faculty of mining, geology and petroleum engineering, university of zagreb) until his retirement in 1987. he attained the position of an assistant (1945–1957), assistant professor (1957– 1959), associate professor (1959–1963) and full professor (1963–1987). from 1965 to 1968 professor jurković worked in the united nations as a principal geologist on prospecting mineral resources in tunisia and additionally in 1966 he become adviser to the united nations in benin, togo and eastern morocco. during this time he fulfilled all his duties as a university professor by using his holidays. professor jurković served as a rector of the university of zagreb between 1978 and 1982 and as the president of the council of the university of zagreb from 1982 to 1984. the title professor emeritus was conferred on him by the senate of the university of zagreb in 2000. in the optical laboratory of dr. arnold cissarz, the former executive officer of the geological bundesanstalt in hannover, who afterwards worked in belgrad, professor jurković came into contact with qualitative and quantitative (berek) ore microscopy methods in 1949. upon the personal invitaivan jurković, professor emeritus of the geology of ore deposits at the faculty of mining, geology and petroleum engineering, university of zagreb, died peacefully, in his home in zagreb on 30 december 2014 at the age of 97. he was the leading mineral resource geologist in the countries of the former yugoslavia where he pioneered both the use of ore microscopy in the study of ore deposits and the understanding of their genesis in the relation to the global tectonic paradigm. he devoted a great part of his time to the community, working tirelessly to develop many projects which promote the public good, education and science, holding a number of important political functions in the croatian parliament and government and serving, among others, as rector of the university of zagreb. with his death, geological science in croatia lost one of its most outstanding scientists. geologia croatica 68/2 161–170 zagreb 2015 geologia croaticageologia croatica geologia croatica 68/2geologia croatica 162 tion of professor paul ramdohr, the most remarkable world mineralogist and specialist in ore microscopy, professor jurković spent the summer semester of 1957 in his department of geology at university of heidelberg studying polished sections of rare ore minerals from professor ramdohr’s collection. the experience, obtained during collaborative work with dr. cissarz and professor ramdohr in ore microscopy, together with field knowledge developed in the 2–3 month long geological field campaigns under the leadership of his mentors professor luka marić (technical faculty, university zagreb), professor mirloslav tajder (faculty of natural sciences, university of zagreb) and professor stojan pavlović (faculty of mining and geology, university of belgrade), and his field work in tunisia, laid the foundation for the later remarkable achievements of professor jurković as a teacher and researcher. professor jurković had a broad knowledge across earth science as a whole. accordingly, his scientific activity extended over mineralogy, geochemistry, petrology and metallic and nonmetallic ore deposits, but certainly his most important scientific work was in the field of ore deposits and metallogeny. he devoted much of his time to original field work, ore microscopy and chemical analyses in the laboratory which included classical chemical analysis, spectrographic analysis, debey-scherrer roentgen analysis, infrared spectroscopy, differential thermal analysis, thermogravimetric analysis, isotopic analyses of oxygen, carbon, sulphur, strontium and lead, fluid inclusion analysis, trace element analysis including rare earth elements, and also electron and proton microprobe analyses. his geological field campaigns were located in croatia, bosnia and herzegovina, slovenia, kosovo, serbia, macedonia, greece, myanmar, india, pakistan, indonesia, egypt, tunisia, benin, togo, marocco and venezuela. as an author or co-author, he published 166 scientific papers and 38 professional papers. the ore deposits which professor jurković researched in detail and prepared for exploitation include the big copper deposit of monywa in myanmar, gold bearing copper deposits in the indonesian islands of sumatra and sulawesi, a tertiary lead-zinc deposit oum geigh in egypt, lead-zincbearing barite fluorite deposits on the el kef region in tunisia and lead-zinc deposits at djebel azered in tunisia. he also investigated barite deposits in the lika, gorski kotar and petrova gora mt., copper bearing siderite deposit of gradski potok and lead-zinc-bearing siderite deposit zrin in the trgovska gora mt., the hematite ore deposit bukovica in petrova gora mt., the pliocene limonite deposit of meterize in trgovska gora mt., magnetite-hematite occurrences in adolfovac in zagrebačka gora mt., bauxite deposits in northern dalmatia, metasomatic monomineral barite deposits in the devonian carbonate rocks in the mid bosnian schist mountains (tarčin, kreševo, kiseljak, brestovsko, fojnica, deževice, dusina, sabiljine pećine, rostovo), vein mercurian-tetrahedrite-bearing barite-siderite deposits in mačkara and mračaj deposits, pyrite-siderite gold vein deposit baković (fojnica), silver-bearing zinc-antimony deposit čemernica (fojnica), cassiterite-bearing magnetite, pyrrhotite, lead-zinc deposit vrtlašce (fojnica), realgar and orpiment deposit hrmza (kiseljak), magnetite hematite, siderite, ankerite, chalcopyrite and arsenopyrite deposit mačje jame, lead-zinc-copper bearing barite deposits in the prača region in southeastern bosnia, bauxite deposits in the former yugoslavia and evaporites in the western dinarides. the topics to which professor jurković made the most important contributions include: detailed mineral, chemical and isotopic analyses of silver and gold-bearing mercurian tetrahedrite and barite, having an important role in the development of the model of ore genesis in the mid bosnian schist mountains, petrological characterization of palaeozoic rhyolite from the vranica mt. and triassic gabbro-diorite from radovan mt. in collaboration with professor vladimir majer, the classification of magnezite deposits of dinarides on the basis of isotopic analyses of oxygen and carbon in collaboration with dr. jakob pamić, the first stratigraphic and paragenetic classification of bauxite deposits in former yugoslavia in collaboration with dr. krešimir sakač, stratigraphic division of gypsum deposits in former yugoslavia in collaboration with professor dubravko šiftar. his classification of all the known deposits in the republic croatia on the basis of stille-bilibin theory was especially valuable. after he retired, professor jurković remained actively engaged in scientific work and pursued his activities with undiminished energy. in the last 7 years he published 8 scientific papers, being the first author of 6 papers. it should be pointed out that the mid bosnian schist mountains was an area of special interest to professor jurković, where he found and described 276 ore deposits and occurrences in the scope of his dissertation. in the last seven years professor jurković again intensively investigated this area introducing modern analytical methods aiming to provide new insights into the chemistry of ore minerals and the age of the rhyolite as well as to develop the most comprehensive model of the genesis of ore deposits. until his last breath he worked on this model. he exerted a great influence on the development of metallogeny in all the countries of the former yugoslavia. under the leadership of professor jurković at faculty of mining, geology and petroleum engineering, university of zagreb, the first „school“ for researchers of metallic and nonmetallic deposits was initiated. besides the many courses he taught, professor jurković introduced a new one „ore microscopy“, and started, (as a first in the former yugoslavia), to give lectures related to optical quantitative investigations of opaque minerals in reflected polarized light according to the berek method. he was also the first in the former yugoslavia to introduce plate tectonics into his lectures regarding the genesis of ore deposits in the frame of the course „ore deposits“. he welcomed and mentored numerous students and geologists from croatia and other countries of the former yugoslavia, illuminating with stark clarity the fundamental principles of ore deposits. he had a tremendous impact on the learning and professional growth of many geologists. professor jurković literally emanated a great experience and enthusiam in the classroom and was without the doubt the best professor the faculty of mining, geology and petroleum engineering, university of zagreb, ever had. vesnica garašić & goran durn: obituary professor emeritus ivan jurković (1917-2014) geologia croatica 163 due to his highly developed sense of responsibility for community, professor jurković became engaged in numerous activities in addition to his academic work. he was very successful in leadership positions and served as the head geologist and the director of the institute of mining and geology in croatia (1947–1949), as the head geologist in the ministry of ferrous and nonferrous metallurgy of the federal government of yugoslavia (1949–1951) and as a counsellor at the federal and republic level for nuclear resources and geological research abroad. always seeking a new challenge to improve the public good, professor jurković, together with professor stjepan težak, initiated the first committee for computing, from which later came the idea to build the university computing centre (srce) for the university of zagreb and other research institutions. as the president of the committee for building four capital cultural institution in croatia (1977–1988) professor jurković significantly contributed to the building of the national and university library, for which he and professor andre mohorovičić laid the foundation stone in 1988. many other important public projects, including the bjelolasica ski resort, molecular biology centre in the franciscan monastery rožat in dubrovnik and astronomical observatory on hvar were accomplished due to the enormous energy and labour of professor jurković. as a rector, he increased the number of postgraduate studies, the number of national scholarships and co-financing for professors from eastern europe in the inter-university centre of postgraduate studies (iuc) in dubrovnik and organized the construction of the dormitory in the iuc building. between 1940 and 2000 professor jurković realized 83 shorter (one week) or longer official journeys in foreign countries. he visited most european countries, asia (myanmar, india, china, turkey, philippines, singapore, thailand), africa (egypt, tunisia, nigeria, benin, togo, morocco), south america (venezuela, brazil), middle america (jamaica, dominican republic, mexico) and north america (florida, washington city, indiana, california, los angeles). professor jurković was extremely active in different domestic and foreign scientific and professional societies. he was a member of the croatian geological society (in one mandate president and member of executive committee), a member of the croatian biological society, a secretary and vice-president of the croatian society of natural sciences, a member of the german mineralogical society, a president of the norwegian-yugoslav friendship society, a member of the society for applied geology deposits, a member of the union of geosciences, a member and president of the international committee for study of bauxite, alumina and al-oxides, a member of the international association on the genesis of the ore deposits, a member of the administrative board (executive commitee) of the international association of the universities, to mention only a few. he was a corresponding member of the croatian academy of sciences and arts (former yugoslav academy of sciences and arts) from 1963 and became a full member in 1969. he contributed greatly to the advancement of this institution being a member of its presidium (1969–1972) and a member of its associations, comittees and councils such as the croatian crystallographic association, geochemistry comittee and acting as the first president of the scientific council for telemetry and scientific council for crude oil and gas. from 1973 he became also a corresponding member of the academy of sciences and arts of bosnia and herzegovina. his sense for community was also reflected in his activity on the editorial boards of numerous scientific journals (geološki vjesnik, acta geologica, rudarstvo, sveučilišni vjesnik, the florida state university proceeding and reports, theoprastus contributions to advanced studies in geology). during his long and fruitful career, professor jurković won many honors and medals. he received the prestigious order of danica hrvatska for science (2012), order of the republic of croatia with golden wreath (1987), order of merits for the people with golden star (1977), order of the republic of croatia with silver wreath (1974), order of labour with golden wreath (1964), order of labour with silver wreath (1953) and medal for merits for the people (1948). he was an honorary member of five professional societies and received many other honours, including 32 plaquettes and charters of numerous notable croatian institutions and faculties. the achievements of professor jurković, as a scientist and a public server, were recognized in many foreign countries whose governments invited him to be a guest, for instance the german government in 1974 and the french government in 1977, and where he obtained medals from ten different universities. professor jurković was an extraordinary and increadibly inspiring professor, an admired orator and a researcher of exemplary diligence. he furthered our knowledge and was supportive of anyone who wanted to learn. due to his scientific enthuasiasm and dedication to the work, brilliant intelligence and extremely good memory which allowed him to make the best possible coordination of all his observations, he earned the respect and admiration of all his colleagues. he was an academic giant and a highly influential personality. the numerous contributions of professor jurković to both academic and overall public life mean that he will be much missed and never forgotten. vesnica garašić and goran durn bibliography scientific papers (current contents) jurković, i., palinkaš, l., garašić, v. & strmić-palinkaš, s. (2012): genesis of vein-stockwork cryptocrystalline magnesite from the dinaride ophiolites.– ofioliti, 37/1, 13–26. pamić, j., balogh, k., hrvatović, h., balen, d., jurković, i. & palinkaš, l. (2004): k-ar and ar-ar dating of the palaeozoic metamorphic complex from the mid-bosnian schist mts., central dinarides, bosnia and herzegovina.– mineralogy and petrology, 82, 65–79. geologia croatica 68/2geologia croatica 164 pamić, j. & jurković, i. (2002): palaeozoic tectonostratigraphic units of the northwest and central dinarides and the adjoining south tisia.– international journal of earth sciences, 91, 538–554. jurković, i. (1960): quecksilberfahlerz vom mačkara gang bei gornji vakuf in bosnien (jugoslawien).– neues jhrb. d. mineral., abh. 94, 539–558. scientific papers in other journals garašić, v. & jurković, i. (2012): geochemical characteristics of different limonite ore types from the southern tomašica iron deposits, nw bosnia.– geologia croatica, 65/2, 255–270. jurković b. i., garašić, v. & jurković m. i. (2011): geochemical characteristics of mercurian tetrahedrite, barite and fluorite from the barite deposits duboki vagan and dubrave-dugi dol, south of the town of kreševo, mid-bosnian schist mountains.– geologia croatica, 64/1, 49–59. jurković, b. i., garašić, v. & jurković, m. i. (2011): cobalt, nickel, tungsten, cadmium, silver and gold-bearing mercurian tetrahedrite from the sasky rad barite – siderite deposit in the midbosnian schist mts.– geologia croatica, 64/3, 223–237. jurković, i., garašić, v. & hrvatović, h. (2010): geochemical characteristics of the barite occurrences in the paleozoic complex of the southeastern bosnia and their relationship to the barite deposits of the mid-bosnian schists mountains.– geologia croatica, 63/2, 241–258. jurković, i. (2007): polymetallic sulphide occurrences in the upper paleozoic complexes of northern montenegro.– rudarskogeološko-naftni zbornik, 19, 11–16. jurković, i. (2006): geology and metallogeny of the drina–ivanjica metamorphic complex in eastern bosnia–western serbia.– rudarsko-geološko-naftni zbornik, 18, 43–61. jurković, i. (2005): magnetite-hematite iron ore occurrences in the triassic-paleozoic metamorphic complex of medvednica mountain, croatia.– rudarsko-geološko-naftni zbornik, 17, 1–14. pamić, j. & jurković, i. (2005): early paleozoic formations within pre–alpine fragments incorporated into the internal dinarides.– acta geologica hungarica, 48/2, 153–179. jurković, i. (2004): metallogeny of eocene syncollisional granites of motajica and prosara mountains.– rudarsko-geološko-naftni zbornik, 16, 31–46. jurković, i. (2003): metalogenija južne tisije – moslavačka gora, psunj, papuk, krndija [the metallogeny of the southern tisia – moslavačka gora mt., psunj mt., papuk mt., krndija mt. – in croatian].– rudarsko-geološko-naftni zbornik, 15, 1–17. jurković, i. & pamić, j. (2002): the magnesites from the dinarides.– rad hazu, 486, 77–110. jurković, i., tončić-gregl, r., strmić, s. & šiftar, d. (2002): geology and geochemistry of the raštelica barite deposits southwest of sarajevo, bosnia and herzegovina.– rudarskogeološko-naftni zbornik, 14, 37–46. jurković, i. & pamić, j. (2001): geodinamska i metalogenetska evolucija paleozojskih kompleksa dinarida i južne tisije u svjetlu tektonike ploča [the geodynamic and metallogenic evolution of palaeozoic complexes of dinarides and southern tisia in the light of plate tectonics – in croatian].– nafta, 52/9, 285–294. jurković, i. & pamić, j. (2001): geodynamics and metallogeny of variscan complexes of the dinarides and south tisia as related to plate tectonics.– nafta 52/9, 267–284. jurković, i. & pamić, j. (1999): triassic rifting-related magmatism and metallogeny of the dinarides.– acta geologica, 26/1, 1–26. jurković, i., ramović, m. & zec, f. (1999): chemical and geochemical characteristics of the čemernica antimonite deposit in the mid-bosnian schist mountains.– rudarsko-geološko-naftni zbornik, 11, 1–16. čop, m., jurković, i. & slovenec, d. (1998): sedimentary lowmanganese hematite deposits of the bukovica area in the northwestern mt. petrova gora, central croatia.– rudarsko-geološko-naftni zbornik, 10, 1–24. jurković, i. & slovenec, d. (1998): geochemical significance of the zincian chrome-spinel for the genesis of the cr-ba-fe-cu-zn ore deposit in the zagrlski brook (bosnia and herzegovina).– acta geologica 25/1, 39–55. slovenec, d., šiftar, d., jakšić, m. & jurković, i. (1997): strontium dependence of the lattice constants of barites from the kreševo area in central bosnia (bosnia and herzegovina).– geologia croatica, 50/1, 27–32. pamić, j. & jurković, i. (1997): alpine magmatic-metallogenic formations of the northwestern and central dinarides.– rudarskogeološko-naftni zbornik, 9, 1–9. jurković, i. & miko, s. (1997): tetrahedrite from the dubrave-dugi dol barite deposits, kreševo, bosnia and herzegovina.– rudarsko-geološko-naftni zbornik, 9, 11–16. jurković, i. (1996): barite, hematite and cinnabar ore deposits in the dusina area, mid-bosnian schist mountains.– rudarsko-geološkonaftni zbornik, 8, 51–65. jurković, i. (1995): bakovići, the biggest gold deposit of bosnia and herzegovina.– rudarsko-geološko-naftni zbornik, 7, 1–15. jurković, i., pezdič, j. & šiftar, d. (1994): geology and geochemistry of the mineralization from the gornji vakuf area, bosnia.– rudarsko-geološko-naftni zbornik, 6, 19–37. jurković, i. & jakšić, m. (1994): a zincian chrome-spinel from the cr-ba-fe-cu-zn deposit near busovača (bosnia and herzegovina).– geologia croatica, 47/1, 83–102. palinkaš, l. & jurković, i. (1994): lanthanide geochemistry and fluid inclusion peculiarities of the fluorite from the barite deposits south of kreševo (bosnia and herzegovina).– geologia croatica, 47/1, 103–115. jurković, i. (1993): mineralne sirovine sisačkog područja [mineral resources of the sisak region, croatia – in croatian].– rudarskogeološko-naftni zbornik, 5, 39–58. jurković, i., šinkovec, b. & grimani, i. (1992): les gites plombo-zincifères du district minier du koudiat sidii au sud du kef en tunisie.– rudarsko-geološko-naftni zbornik, 4, 7–13. jurković, i. & zalokar, b. (1990): the copper deposit of batu marupa in central sulawesi, indonesia.– rudarsko-geološko-naftni zbornik, 2, 29–33. jurković, i. (1990): iron-ore deposits in the kosna ore field, trgovska mountain, croatia.– geol. vjesnik, 43, 187–194. jurković, i. & zalokar, b. (1990): paragenetic and genetic characteristics and mode of occurrence of some gold-bearing copper deposits in island sumatra, indonesia.– geol. vjesnik, 43, 195–209. crnički, j. & jurković, i. (1989): rare earth elements in triassic bauxites of croatia (yugoslavia).– the icsoba congress – brasil 1988, travaux, 19/22, 239–248. jurković, i. (1989): the zinc deposit agios elefterios (glyka nera) south-east of athens in greece.– geol. vjesnik, 42, 333–345. jurković, i. (1989): copper ore deposits in the gradski potok ore field of the trgovska gora district of croatia.– geol. vjesnik, 42, 347–365. jurković, i. (1989): galena-bearing ore occurrences in the čatrnja district of trgovska gora in croatia.– rudarsko-geološko-naftni zbornik, 1, 23–28. jurković, i. (1989): kvantitativna optička istraživanja realgara iz arsenske rudne pojave banjak južno od kiseljaka u bosni [quantitative optical investigation of the realgar from the arsenic-bearing vesnica garašić & goran durn: obituary professor emeritus ivan jurković (1917-2014) geologia croatica 165 deposit banjak south of the town of kiseljak in bosnia – in croatian].– rudarsko-geološko-naftni zbornik, 1, 17–21. jurković, i. (1988): hercinska metalogeneza rudnih ležišta trgovske gore u hrvatskoj [the hercynian metallogeny of the ore deposits of trgovska gora in croatia – in croatian].– geol. vjesnik, 41, 369–393. jurković, i. (1988): ore deposits in the duboki vagan region south and south-west of the town of kreševo, bosnia.– geol. vjesnik, 41, 355–367. jurković, i. & durn, g. (1988): lead deposits in the zrin district of trgovska gora in croatia.– geol. vjesnik, 41, 317–339. jurković, i., šinkovec, b., grimani, i., berce, b. & crnički, j. (1988): les gîtes plombo-zincifères djebel et tarabia et djebel el gassaa, tunisie.– geol. vjesnik, 41, 341–354. jurković, i., šinkovec, b. & berce, b. (1987): les gîtes plombo-zincifères koudiat el behmia (el menaa), tunisie.– geol. vjesnik, 40, 337–350. jurković, i. (1987): barite deposits on mount međuvršje south and south–east of the town of kreševo, bosnia.– geol. vjesnik, 40, 313–336. jurković, i., grimani, i. & šinkovec, b. (1986): les gîtes plombo-zincifères koudiat zag et tir et koudiat oum hadhoud, tunisie.– geol. vjesnik, 39, 225–235. jurković, i. (1986): quantitative chemical and optical investigations of the tetrahedrite from barite-bearing deposit vidici on the northern slopes of the mountain medjuvršje south of the town of kreševo, bosnia.– geol. vjesnik, 39, 187–224. jurković, i. (1975): caracteristiques générales des gisements plombo-zincifères du djebel hamra en tunisie centrale.– acta geologica 8/6, prirodoslovna istraživanja, 41, 77–84. jurković, i. (1970): filons de quartz sulfuré aux environs d’agbandi, togo (afrique).– zbornik radova rudarsko-geološko-naftnog fakulteta, 1, 113–121. jurković, i., zalokar, b. & marić, l. (1965): notes on the ore occurrences on the eastern and south-eastern, slopes of tagaungtaung, katha-district, upper burma (asia).– geol. vjesnik, 18/1, 53–60. jurković, i. (1965): lithological types of bauxite in the suvaja-šolaja region near bosanska krupa and their structural elements, acta geologica, 4, 101–110. jurković, i. (1964): some geochemical aspects about the genesis of the nickel deposit loma de hierro (venezuela).– geol. vjesnik, 17, 103–112. majer, v. & jurković, i. (1963): bilješka o nalazu krom-spinela kod čelinca u bosni [the note about the finding of chromian spinel near čelinac in bosnia – in croatian].– geol. vjesnik, 15/2, 337–339. zalokar, b. & jurković, i. (1962): copper deposits of the southern shan states, burma.– geol. vjesnik, 15/1, 229–248. jurković, i. (1962): rezultati naučnih istraživanja rudnih ležišta u nr hrvatskoj [the results of the scientific researches of ore deposits in national republic croatia – in croatian].– geol. vjesnik, 15/1, 249–294. jurković, i. (1962): parageneze rudnih pojava u oblasti čemernice kod fojnice, bosna i hercegovina [parageneses of the ore occurrences in the area of čemernica near fojnica, bosnia and hercegovina – in croatian].– geol. glasnik, 6, 141–156. jurković, i. (1962): kvantitativna optička i spektrografska istraživanja antimonita od čemernice kod fojnice [quantitative optical and spectrographic investigrations of antimonite from čemernica near fojnica – in croatian].– geol. glasnik, 6, 13–22. jurković, i. & zalokar, b. (1961): silver–bearing galena and siderite occurrences in the putao region, northern burma (asia).– geol. vjesnik, 14, (1960), 311–322. zalokar, b. & jurković, i. (1961): copper ore occurrence kyaukse, burma.– geol. vjesnik, 14, (1960), 265–270. jurković, i. & zalokar, b. (1961): copper ore occurrences at buddha kola in south-central nepal, asia.– geol. vjesnik, 14, (1960), 301–310. jurković, i. (1961): minerali željeznih rudnih ležišta ljubije kod prijedora [minerals of iron ore deposits ljubija near prijedor – in croatian].– geol. vjesnik, 14, (1960), 161–220. šiftar, d. & jurković, i. (1961): viterit od homera u gorskom kotaru [the witherite from homer in gorski kotar – in croatian].– geol. vjesnik, 14, (1960), 89–95 jurković, i. (1960): realgar i auripigment u rudnim ležištima srednjobosanskog rudogorja [realgar and orpiment in the ore deposits of the mid-bosnian ore mountains – in croatian].– geol. glasnik, 5, 199–240. jurković, i. (1960): polymetal parageneses of the ore occurrence in the catchment area of the srebrnjak brook south of the town dvor na uni, croatia.– geol. vjesnik, 13, (1959), 149–161. jurković, i. & gazarek, m. (1960): kremeni pijesak brezičana kao sirovina za proizvodnju plinobetona [quartzsand from the brezičani as raw material for the production of gas-concrete – in croatian].– kemija u industriji, 9/9, nemetali 6/3, god. 2, 31–36. jurković, i. & gazarek, m. (1960): pojave gipsa i anhidrita kod sela biljani kraj sanice gornje, bosna i hercegovina [the occurrences of gypsum and anhydrite at the village biljani near sanica gornja, bosnia and herzegovina – in croatian].– kemija u industriji, vol. 9/6, nemetali br. 6/2, god. ii, 11–16, zagreb, 1960. jurković; i. & zalokar, b. (1959): the ore occurrences of the shangalon area, southwestern of kawlin, upper burma.– geol. vjesnik, 12, (1958), 235–265. jurković, i. & zalokar, b. (1959): notes on the ore occurrences in wuntho region, burma.– geol. vjesnik, 12, (1958), 125–134. jurković, i. (1959): magnetitsko ležište muhamedbegova prisjeka kod ključa, u bosni [the magnetite deposit of muhamedbegova prisjeka near ključ – in croatian].– geol. vjesnik, 12, (1958) 115–124. jurković; i. (1959): pojave barita u hrvatskoj [barite occurrences in croatia – in croatian].– geol. vjesnik, 12, (1958), 77–94. jurković, i. (1959): pojave živinog tetraedrita u području gornjeg vakufa [the occurrences of mercurian tetrahedrite in the region of gornji vakuf – in croatian].– tehnika, rudarstvo i metalurgija, 7, 1135–1139. jurković, i. (1958): metalogenija petrove gore u jugozapadnoj hrvatskoj [metallogeny of petrova gora in southwestern croatia – in croatian].– geol. vjesnik, 11, (1957), 143–228. majer, v. & jurković, i. (1958): diorit bijele gromile južno od travnika u srednjobosanskom rudogorju [diorite of bijela gromila south from travnik in the mid-bosnian ore mountains – in croatian].– geol. vjesnik, 11, (1957), 129–142. jurković, i. (1958): kasiterit, stanin i molibdenit u rudnoj pojavi vrtlasce kod klisca, srednjobosansko rudogorje [cassiterite, stannite and molybdenite from the ore occurrence vrtlasce near klisac, in the mid-bosnian ore mountains – in croatian].– geol. glasnik, vol. 4, 309–320. jurković, i. (1958): tetraedrit iz rudne pojave trošnik kraj fojnice u srednjobosanskom rudogorju [tetrahedrite from the ore occurrence of trošnik near fojnica in the mid-bosnian ore mountains – in croatian].– geol. glasnik, vol. 4, 221–246. jurković, i. (1956): burnonit u baritnoj pojavi rimska jama kod kreševa [burnonite in the barite occurrence rimska jama near kreševo – in croatian].– geol. glasnik, 2, 5–20. geologia croatica 68/2geologia croatica 166 jurković, i. & majer, v. (1954): rioliti (kremeni porfiri) vranice planine i albitski riolit sinjakova u srednjobosanskom rudogorju [rhyolite (quarzporphyre) from vranica mt. and albite rhyolite (quartzkeratophyre) from sinjakovo in the mid-bosnian ore mountains – in croatian].– vesnik zavoda za geološka i geofizička istraživanja rn srbije, 11, 207–233. jurković, i. (1954): novootkrivena eruptivna pojava na brdu inač kod kreševa [the new discovered occurrence of eruptive at the hill inač near kreševo – in croatian].– geol. vjesnik, 5–6, (1951–1953), 367–370. jurković, i. (1954): ni-lineit (siegenit) i milerit u turmaliniziranom baritu kod brestovskog u srednjobosanskom rudogorju [ni-lineite (siegenite) und millerite in tourmalinated baryte near brestovsko in the mid-bosnian ore mountains – in croatian].– geol. vjesnik, 5–7, (1951–1953), 273–294. jurković, i. (1954): augitsko-labradorski andezit od orašina jugoistočno od bakovića, bosna [augite labradorite andesite from orašine sourtheasten from bakovići, bosnia – in croatian].– geol. vjesnik, 5–7, (1951–1953), 111–126. jurković, i. (1953): granat u skarnu novog brda, kosovo [garnet in the skarn of novo brdo, kosovo – in croatian].– vesnik zavoda za geološka i geofizička istraživanja nr srbije, 10, 125–134. jurković, i. (1953): barit iz rudnika dobrevo kod zletova, makedonija [barite from the dobrevo mine near zletovo, macedonia – in croatian].– spomenica miši kišpatiću, 221–235. plotnikov, i., proštenik, m. & jurković, i. (1939): änderung des chemiluminiscenzlichtes mit schichtdicke [the change of the chemiluminescence light with a thickness – in german].– photographische korrespodenz, 75, 6, 91–93. conference presentations, proceedings, abstract-books jurković, b.i., garašić, v. & jurković m.i. (2010): geochemical characteristics of mercurian tetrahedrite frome the barite-siderite deposit saski rad, gornji vakuf, mbsm.– in: horvat, m. (ed): 4. croatian geological congress – šibenik 2010, abstract book. croatian geological survey, zagreb, 344–345. garašić, v. & jurković, i. (2010): geochemical characteristics of the rostovo calcite–barite–hg–tetrahedrite ore deposits in the mid– bosnian schist mountains.– in: horvat, m. (ed): 4. croatian geological congress – šibenik 2010, abstract book. croatian geological survey, zagreb, 338–339. jurković, i. (2005): paleozoic iron ore occurrences in the medvednica mountain, croatia.– in: velić, i., vlahović, i. & biondić, r. (eds): 3. croatian geological congress – opatija 2005, abstract book. croatian geological survey, zagreb, 69–70. pamić, j., balogh, k., hrvatović, h., balen, d., jurković, i. & palinkaš, l. (2001): polyphase metamorphic evolution of the mid-bosnian schist mts. (mbsm). paleozoic complex from the central dinarides (bosnia and herzegovina).– in: adam, a., szarta, l. & szendröi, j. (eds): pancardi ii – sopron, hungary 2001, abstracts. geodetic and geophysical research institute of the has. palinkaš, l., strmić, s., jurković, i., & hrvatović, h. (2001): epithermal gold deposits in central bosnia.– geode workshop: “geodynamics and ore deposit evolution of the alpine-balkan-carpathian-dinaride-province” – vata bai, romania, 2001, romanian journal of mineral deposits, 79/2, 77. palinkaš, l., strmić, s., garašić, v., jurković, i. & majer v. (2001): permian metarhyolites and related ore deposits, central bosnia.– geode workshop: “geodynamics and ore deposit evolution of the alpine-balkan-carpathian-dinaride-province” – vata bai, romania, 2001, romanian journal of mineral deposits, 79/2, 75–76. jurković, i. & palinkaš, l. (2001): discrimination criteria for assigning of ore deposits located in the dinaric triassic-paleozoic formations to the variscan or alpine metallogeny.– eleventh biennial meeting of the european union of geosciences (eug 11) – strasbourg 2001, journal of conference abstracts. cambridge publication, 5, 267. palinkaš, l., strmić, s., pavlović, g., jurković, i. & hrvatović, h. (2000): evolution of ore-forming fluids in the midbosnian schist mountains.– in: tomljenović, b., balen, d. & saftić, b. (eds): pancardi 2000 – pannonian basin, carpathian and dinaric system. geological meeting on dynamics of ongoing orogeny – dubrovnik 2000, vijesti special issue. croatian geological society, zagreb, 37/3, 99–101. strmić, s., palinkaš, l., jurković, i. & hrvatović, h. (2000): the fluids in quartz from the middle bosnia.– in: vlahović, i. & biondić, r. (eds): 2. croatian geological congress – cavtat 2000, proceedings. croatian geological survey, zagreb, 415–419. jurković, i. (2000): nov koncept sistematizacije primarnih rudnih pojava genetski vezanih za lercolitski pojas ofiolita dinarida [a new concept of systematics of primary ore deposits bounded genetically to the lherzolite ophiolite belt of the dinarides – in croatian].– in: vlahović, i. & biondić, r. (eds): 2. croatian geological congress – cavtat 2000, proceedings. croatian geological survey, zagreb, 613–620. jurković, i., palinkaš, l., balogh, k. & ramović, m. (1999): an uncommon antimony, zinc, mercury, tungsten, lead, iron-bearing quartz vein system at fojnica, mid-bosnian schist mountains.– tenth biennal meeting of the european union of geosciences (eug 10) – strasbourg 1999, journal of conference abstracts. cambridge publication, 4/1, 474. palinkaš, l., pavlović, g., jurković, i. & hrvatović, h. (1999): fluids in quartz from central bosnia. indicators of alpine retrogressive metamorphism.– in: faryad, s.w. (ed): ii field meeting of carpathian – balkan association – košice, slovakia 1999, special issue of the acta montanistica slovaca, 23–25. palinkaš, l., bermanec, v., jurković, i., zebec, v. & pavlović, g. (1997): ammonium ion bearing hyalophane feldspar, busovača, central bosnia; metamorphogenic origin constrained by co2 – inclusion study.– in: kroner, a. (ed): ninth biennal meeting of the european union of geosciences (eug-9) – strasbourg 1997, terra nova abstracts. cambridge publication, 9/1, 552. jurković, i., pamić, j., šiftar, d. & palinkaš, l. (1997): geochemical characteristics of late-proterozoic-early paleozoic, variscan and alpine magmatic-metallogenic formations of dinarides.– ninth biennal meeting of the european union of geosciences (eug-9) – strasbourg 1997, terra nova. cambridge publication, 9/1, 533. jurković, i. & palinkaš, l. (1997): gold-bearing pyrite deposits in the central dinarides.– society of economic geologists (seg) neves corvo field conference – lisboa 1997, guiedebook series, 27, 1–6. palinkaš, l., majer, v., balogh, k., bermanec, v. & jurković, i. (1996): geochronometry and termochronometry of the metamorphism in the inner dinarides, mbsm.– annual meeting of unesco igcp project no 356 – sofia 1996. jurković, i. & palinkaš, l. (1996): late variscan, middle-upper permian, post-variscan and middle triassic rifting related ore deposits in the northwestern and central dinarides.– proceedings of the annual meeting, unesco project no 356, plate tectonic aspects of the alpine metallogeny in the carpatho-balkan region – sofia 1996. university of mining and geology “st. ivan rilski”, 1, 19–27. jurković, i. & pamić, j. (1996): permo-triassic rifting related magmatic-metallogenic formations of the dinarides.– meeting of the vesnica garašić & goran durn: obituary professor emeritus ivan jurković (1917-2014) geologia croatica 167 unesco project 369 “comparative evolution of peri-tethyan rift basins” – budapest 1996. proceedings. jurković, i., palinkaš, l., slovenec, d., šiftar, d. & pezdič, j. (1995): paragenesis, geochemistry and crystallochemistry of the barite deposits in the mid-bosnian schist mountains.– eight biennal meeting of the european union of geosciences (eug-8) – strasbourg 1995. terra nova. cambridge publication, 7, 331. pamić, j. & jurković, i. (1995): alpine magmatic-metallogenic formations of the northwestern and central dinarides.– 15. congress of the carpatho-balkan geological association, igcp project no 356 – athens 1995. jurković, i. (1995): metalogenija paleozoika dinarida na području slovenije, hrvatske, bosne i hercegovine, crne gore i makedonije [paleozoic metallogeny of dinarides in the area of slovenia, croatia, bosnia-herzegovina, montenegro and western macedonia – in croatian].– in: vlahović, i., velić, i. & šparica, m. (eds): 1. croatian geological congress – opatija 1995, proceedings. croatian geological survey, zagreb, 1/275–280. jurković, i. (1995): metalogenija paleozoika dinarida na području slovenije, hrvatske, bosne i hercegovine, crne gore i zapadne makedonije [paleozoic metallogeny of dinarides in the area of slovenia, croatia, bosnia-herzegovina, montenegro and western macedonia – in croatian].– in: vlahović, i., velić, i. & šparica, m. (eds): 1. croatian geological congress – opatija 1995, abstracts. croatian geological survey, zagreb, p. 46. palinkaš, l. & jurković, i. (1994): siderite-barite-polysulphide deposits from petrova and trgovska gora mts., central croatia, precursors of the post-variscan metallogeny.– int. conference: “variscan metallogeny in the alpine orogenic belt” – stara lesna (slovakia) 1994. abstracts and excursion guide, p. 16. palinkaš, l. & jurković, i. (1994): genesis of ljubija siderite deposit: metallogenic implications.– second meeting of “plate tectonics and metallogeny in the east carpathian and apuseni mts”, igcp project no 356 – baia mare (romania) 1994. abstracts, p. 28. jurković, i., šiftar, d., palinkaš, l. & pezdič, j. (1994): geological and geochemical characteristics of the variscan and postvariscan barite deposits of the western dinarides.– int. conference: “variscan metallogeny in the alpine orogenetic belt” – stara lesna (slovakia) 1994. abstracts and excursion guide, p. 23. jurković, i. & palinkaš, l. (1994): geochemistry of the rift related metallogeny in the dinarides.– second meeting of “plate tectonics aspects of alpine metallogeny in the carpatho-balkan region”, igcp project no 356 – baia mare (romania) 1994. abstracts, p. 29. palinkaš, l. & jurković, i. (1993): geochemistry of hydrothermal ore forming processes in the mid-bosnian schist mountains.– symposium “metamorphic fluids and mineral deposits”. final meeting of the igcp project no 291 – prague 1993. abstracts, p. 43. jurković, i., slovenec, d. & namjesnik, k. (1993): an uncommon metamorphic cr-ba-fe-cu deposit from the busovača district, central bosnia.– 6. congress of the geological society of greece – athens 1993, bulletin of the geological society of greece, 28/3, 677–690. palinkaš, l. & jurković, i. (1993): lanthanide geochemistry and fluid inclusion peculiarities of the fluorite from the barite deposits south of kreševo, bosnia.– seventh biennal meeting of the european union of geosciences (eug vii) – strasbourg 1993, terra nova abstracts. cambridge publication, 5/1, p. 464. jurković, i. & jakšić, m. (1993): the zincian-chrome spinel from the cr-ba-fe-cu-zn deposit near busovača, bosnia. its composition, alteration, and genetic significance.– seventh biennal meeting of the european union of geosciences (eug vii) – strasbourg 1993, terra nova abstracts. cambridge publication, 5/1, p. 353. jurković, i., slovenec, d. & namjesnik, k. (1992): the uncommon metamorphic cr-ba-fe-cu-deposit from the busovača district, central bosnia, yugoslavia.– 6th congress of the geological society of greece – athens 1992, proceedings, 49–50. jurković, i. (1991): gold and silver-bearing hg-tetrahedrite deposits in central bosnia, yugoslavia.– 6th biennal meeting of the european union of geosciences (eug vi) – strasbourgh 1991, proceedings, 411. jurković, i. (1990): pliocenska ležišta limonita tip “meterize” u trgovskoj gori, hrvatska [pliocene limonite iron ore deposits type “meterize” in trgovska gora, croatia – in croatian].– 12. geologi cal congress of yugoslavia – ohrid 1990, rudna naógališta, geohemija, metalogenija i ekonomska geologija, ohrid, 3, 1–13. jurković, i. (1989): metallogenic epochs in the palaeozoic of the dinarides of yugoslavia.– 79th annual meeting of the “geologische vereinigung”. mineral deposits – leoben 1989, terra nova abstracts. blackwell scientific publications, oxford, 1, p. 53. jurković, i. (1989): rudne pojave između kreševa i deževica u srednjobosanskom rudogorju [ore deposits between kreševo and deževica in the mid-bosnian ore mountains – in croatian].– simpozij “minerali, stijene, izumrli i živi svijet bosne i hercegovine – sarajevo 1988, zbornik referata, 19–35. jurković, i. (1988): rudne pojave između kreševa i deževica u srednjobosanskom rudogorju [ore occurrences between the towns of kreševo and deževica in the mid–bosnian schist mts. – in croatian].– simpozij “minerali, stijene, izumrli i živi svijet bosne i hercegovine” – sarajevo 1988, zbornik sažetaka, p. 11. jurković, i. (1989): mineralne sirovine sisačkog područja [mineral row material from the sisak region – in croatian].– simpozij “sisak – više od 2000 godina postojanja” u organizaciji jazu i općine sisak – sisak 1989. sažeci referata, 5–6. jurković, i. & sakač, k. (1964): stratigraphical, paragenetical and genetical characteristics of bauxites in yugoslavia.– extrait des actes du symposium sur les bauxites, oxides et hydroxydes d’aluminium. jazu – zagreb 1963, travaux de l’icsoba, 1, 258–263. jurković, i. (1959): komparativna studija metalogenih oblasti u paleozoiku gorskog kotara, like, petrove i trgovske gore u hrvatskoj, te unskog, sanskog, srednjobosanskog i pračanskog paleozoika u bosni [the comparative study of the metallogenic regions in the paleozoic complexes of gorski kotar, lika, petrova and trgovska mts. in croatia and in the paleozoic of una–sana, mid–bosnian and prača regions in bosnia – in croatian].– 3. geological congress of yugoslavia – budva 1959, proceedings, 1–5. jurković, i. (1957): the basic characteristics of the metallogenic region of the mid-bosnian ore mountains.– 2. geological congress of yugoslavia – sarajevo 1957, proceedings, 504–519. majer, v. & jurković, i. (1957): petrological characteristics of the diorite of bijela gromila south of travnik (bosnia).– 2. geological congress of yugoslavia – sarajevo 1957, proceedings, 263–270. chapters in books jurković, i. (2005): neoproterozoic and early palaeozoic metallogenies in the dinarides, south tisia, pelagonides and serbo-macedonian mass.– in: jingwen, m. & bierlein, f.p. (eds): mineral deposit research: meeting the global challenge: proceedings of the 8th biennal sga meeting – beijing 2005. springer, berlin, 1, 19–22. jurković, i. & pamić, j. (2003): carbon and oxygen isotope composition of the dinaridic ophiolite related magnesites.– in: eliopoulos, d. (ed): mineral exploration and sustainable development: proceedings of the 7th biennial sga meeting – athens 2003, millpress, rotterdam, 883–886. jurković, i. & palinkaš, l. (2002): discrimination criteria for assigning ore deposits located in the dinaridic. palaeozoic-triassic formations to variscan or alpidic metallogeny.– in: blundell, d. j., neubauer, f. & von quadt, a. (eds): the timing and geologia croatica 68/2geologia croatica 168 location of major ore deposits in an orogen. geological society, special publications, london, 204, 229–245. jurković, i. (2001): paragenetical and geochemical differences of mineral deposits between lherzolite and harzburgite-dunite ophiolite belts of the dinarides.– in: piestrzynski, a. (ed): mineral deposits at the beginning of the 21st century”: proceedings of the joint 6th biennal meeting – krakow 2001. balkema, lisse-abingdon-exton (pa), tokyo, 591–594. jurković, i. & palinkaš, l. (1999): sulphur isotope and fluid inclusion data of barites from the dinarides.– in: stanley, c.j. (ed): mineral deposits, processes to processing: proceedings of the 6th biennal meeting of sga and iagod – london 1999, balkema, roterdam, 45–49. pamić, j. & jurković, i. (1997): bosnia and herzegovina.– in: moores, e.m. & fairbridge, r.w. (eds): encyclopedia of european and asian regional geology”. chapman & hall, london, 86–93. jurković, i., palinkaš, l., slovenec, d., šiftar, d., miko, s., jakšić, m. & pezdič, j. (1997): geochemical characteristics of mercurian tetrahedrites from the middle bosnian schist mountains.– in: papunen, h. (ed): mineral deposits: research and exploration. where do they meet ? – proceedings of he 4th biennal sga meeting – turku 1997. balkema, rotterdam, 829–832. jurković, i. & šiftar, d. (1995): sulphate sulphur isotope composition of evaporites in the western dinarides.– in: pašava, j., kribek, b. & zak, k.: mineral deposits: from their origin to their environmental impacts: proceedings of the 3th biennal sga meeting – prague 1995. balkema, rotterdam, 581–584. professional papers jurković, i. (1989): osnivanje znanstvenog savjeta za naftu pri jugoslavenskoj akademiji znanosti i umjetnosti i njegov značaj [the foundation of the scientific council for petroleum and gas in jazu and its importance – in croatian]. – nafta 40, 4–5, 189–193. jurković, i. (1985): interuniverzitetski centar u dubrovniku (iuc) [interuniversity centre in dubrovnik (ius) – in croatian].– sveučilišni vjesnik, 31, 495–498, 155–159. jurković, i. (1985): prikaz djelatnosti međunarodnog udruženja univeziteta (international association of the universities, iau) za razdoblje 1980–1985 [overiew of the activity of international association of the universities (iau) for the period from 1980 to 1985 – in croatian].– sveučilišna naklada liber, zagreb, 1985, 1–139. jurković, i. (1984): međunarodna suradnja sveučilišta u zagrebu (1982–1983). dio i – bilateralna suradnja s pojedinim univerzitetima [international cooperation of the zagreb university (1982– 1983). part i.– bilateral cooperation with individual universities – in croatian].– sveučilišna naklada liber, zagreb, 1984, 1–320. jurković, i. (1984): međunarodna suradnja sveučilišta u zagrebu (1982–1983). dio ii – multilateralna suradnja univerziteta; bilateralne i multilateralne rektorske konferencije [international cooperation of the zagreb university (1982–1983). part ii – multilateral cooperation of the universities; bilateral and multilateral rector conferences – in croatian].– sveučilišna naklada liber, zagreb, 1984, 1–154. jurković, i. (1982): cooperation between balkan states in science and technology. published in edition: first rector conference of universities in balkan countries.– beograd university, 1982, 1–13. majer, v. & jurković, i. (1982): monografija “međunarodna suradnja sveučilišta u zagrebu (1964–1982)” [monography: “international cooperation of the zagreb university between 1964 and 1982.” – in croatian].– sveučilišna naklada liber, studija 1, zagreb, 1–460. höffer, d. & jurković, i. (1982): etape razvoja tekstilno-odjevne proizvodnje kao funkcija razvojnih faktora [the development stages of the texile-clothing industry as a function of the development factors – in croatian].– zbornik radova savjetovanja: znanost i proizvodnja u tekstilnoj i odjevnoj industriji. izdanje saveza inženjera i tehničara tekstilaca hrvatske, zagreb, 1–15. jurković, i. (1980): vključenie viščajušćihsja specijalistov v process obučenija v visših učevnih zavedenijah.– predavanje održano na međurektorskoj konferenciji sssr – jugoslavija, separatni otisak, moskva, 1–13. šinkovec, b. & jurković, i. (1980): sirovine i prirodni uvjeti [resources and natural conditions – in croatian] – in: referati simpozija materijalni i društveni razvoj sr hrvatske do 2000. godine. jazu i republički komitet za znanost, tehnologiju i informatiku, zagreb, 71–78. jurković, i. (1980): development tendencies in student university enrollment in yugoslavia.– 7th general conference of the iau (international association of universities), manila 1980, 1–17. pintar, m. & jurković, i. (1980): basic characteristics of selfmanaging decision making in yugoslavia, yugoslav experience.– scientia yugoslavica, zagreb, 6 (1–4), 29–35. pintar, m. & jurković, i. (1979): osnovne značajke samoupravnog odlučivanja u jugoslaviji [basic characteristics of selfmanaging decision in yugoslavia – in croatian].– in: vrednovanje u znanosti i tehnologiji teorija i praksa. internacionalni simpozij dubrovnik 1979. republički komitet za znanost, tehnologiju i informatiku, zagreb, 1980, 1–5. kniewald, z. & jurković, i. (1979): značenje znanstvenog rada u prehrani i prehrambenoj industriji [character of the scientific investigation in nutrition and in the nutritional industry – in croatian].– agronomski glasnik, 5–6, 697–704. jurković, i., sakač, k., bodružić, d., eleršek, i., gabrić, a., grandić, s., kovačević, s., šinkovec, b. & šušnjara, a. (1979): studija o dugoročnom istraživanju boksita u sjevenoj dalmaciji [study of long term investigation of boxites in the north dalmatia – in croatian].– nosilac projekta “industroprojekt”, a suradnici geološki zavod zagreb, geofizika, jadral obrovac i rgn fakultet zagreb. studija je izrađena za komisiju republičkog savjeta za naučni rad i poduzeće jadral, jadranski aluminij i obrovac. jurković, i. & šinkovec, b. (1978): razvoj geologije rudnih ležišta u sr hrvatskoj u proteklih 25 godina (1951–1976) [the development of the ore geology in sr croatia during last 25 years (1951–1976) – in croatian].– symposium on the occasion of 25 years of croatian geological society. geol. vjesnik, 30/2, 649–655. jurković, i. & adamčić, b. (1977): samoupravne interesne zajednice znanosti [selfmanaging scientific communities – in croatian].– samoupravno interesno organiziranje, zagreb, 211–227. jurković, i. & majer, v. (1975): spomenica u počast akademiku luki mariću prigodom 75-godišnjice života [memorial to honour the 75th anniversary of the life of academician luka marić – in croatian].– jazu, acta geologica, prirodoslovna istraživanja, 41, 8, 1–25. marić, l., šinkovec, b. & jurković, i. (1973): mineralne sirovine like i perspektive njihova korištenja. [mineral resources in the lika region and the perspective of their using – in croatian].– simpozij “lika u prošlosti i sadašnjosti”. jazu, zbornik, 5, 87–97. jurković, i. (1970): uvodni pozdravni govor na 7. kongresu geologa sfrj [introductory speech on 7. geological congress of yugoslav geologists – in croatian].– knjiga 1, str. 1–8. jurković, i. (1969): uvodna riječ na osnivačkoj skupštini znanstvenog savjeta za naftu pri jazu [introductory speech on the inaugural constitution of the scientific council for oil, jazu – in croatian].– jazu, posebni radovi, 1, 11–13. majer, v. & jurković, i. (1969): povodom 70-godišnjice rođenja akademika luke marića [the 70th anniversary of the birth of academician luka marić – in croatian].– geol. vjesnik, 22, 573–575. vesnica garašić & goran durn: obituary professor emeritus ivan jurković (1917-2014) geologia croatica 169 public lectures palinkaš, l. & jurković, i. (1993): značaj istraživanja rijetkih zemalja i fluidnih inkluzija u fluoritima iz kreševa, bosna [the importance of the investigations of the rare earth elements and fluid inclusions in fluorite minerals from kreševo, bosnia – in croatian].– odbor za geokemiju hazu, zagreb, 1993. jurković, i., dragičević, i. & pokrajčić, i. (1990): ležišta boksita u pokrajini oruro, brazil [bauxite ore deposits in the oruro area, brasil].– hrvatsko geološko društvo, zagreb, 1990. jurković, i. (1983): selection of the university professors. the role of the university. introductory exposition.– round table: position and organization of universities–managing problems.– c.r.e. genevè and yugoslav universities, dubrovnik, 22–24.08.1983. jurković, i. (1966): gîtes plombo-zincifères du djebel azered, tunisie centrale. lecon invitée tenue sur le symposium sur le plomb et zinc en afrique organisé par l’association des géologues africaines.– tunis, 1966. jurković, i. (1959): olovno–cinkana ležišta između qosseir i marsa alan na obali crvenog mora u egiptu. [lead–zinc ore deposits between qosseir and marsa alan on the red sea shore, egypt – in croatian].– hrvatsko geološko društvo, zagreb, 29.05.1959. jurković, i. (1959): pojave kobaltnih i nikaljnih minerala u trgovskoj gori [cobalt and nickel ore occurrences in the trgovska gora mt.– in croatian].– hrvatsko geološko društvo, zagreb, 13.02.1959. jurković, i. (1958): sedimentna ležišta barita kod ričica i pilara u lici [sedimentary barite deposits at ričice and pilar villages in lika – in croatian].– hrvatsko geološko društvo, zagreb, 10.01.1958. jurković, i. (1957): o osnovnom gorju u području petrove gore na temelju mikroskopskih ispitivanja paleozojskih naslaga [results of microscopic investigation of the paleozoic sediments in petrova gora mt. – in croatian].– hrvatsko geološko društvo, zagreb, 22.03.1957. jurković, i. (1957): sedimentan način postanka baritnih ležišta u paleozoiku gorskog kotara. [sedimentary origin of the barite deposits in the paleozoic in gorski kotar region. – in croatian].– hrvatsko prirodoslovno društvo, zagreb, 15.02.1957. jurković, i. (1956): geneza i parageneza kontaktno–pneumatolitskog pirotinsko–halkopiritskog ležišta nankesan u sjevernoj burmi (mianmar) [genesis and paragenesis of the contact–pneumatolytic pyrrhotite chalcopyrite deposit nankesan in the northern burma (myanmar) – in croatian].– hrvatsko geološko društvo, zagreb, 23.11.1956. jurković, i. & ferenčić, a. (1956): osnovne karakteristike metalogenog područja korduna [basic characteristics of the metallogenic region of kordun – in croatian].– hrvatsko prirodoslovno društvo, zagreb, 11.05.1956. jurković, i. (1947): o vulkanima [the volcanos – in croatian].– hrvatsko prirodoslovno društvo, zagreb, 1947. jurković, i. (1946): ima li života u svemiru? [is there life in cosmos? – in croatian].– hrvatsko prirodoslovno društvo, zagreb, 1946. jurković, i. (1946): građa sunčeva sistema [the structure of the solar system – in croatian].– hrvatsko prirodoslovno društvo, zagreb, 1946. student scripts jurković, i. (1987): mineralna ležišta u svjetlu teorije globalne tektonike ploča [mineral deposits and global plate tectonics – in croatian].– skripta za studente geologije i rudarstva, rudarskogeološko-naftni fakultet, sveučilište u zagrebu, 1987, 1–124. jurković, i. (1986): nauka o rudištima. part ii – magmatska rudna ležišta [ore deposits. part ii – magmatic ore deposits – in croatian].– skripta, rudarsko-geološko-naftni fakultet, sveučilište u zagrebu, 1986, 1–181. jurković, i. & vragović, m. (1983): ležišta nemetalnih sirovina [nonmetallic ore deposits – in croatian].– priručna skripta za studente geologije i kemije, rudarsko-geološko-naftni fakultet, sveučilište u zagrebu, 1–95. jurković, i. (1983): translation of some englisch scientific boucklet for students of geology and mining: “origin of oceans” of e. bullard (1969) and “bottoms of deep oceans” of h.w. menard (1969).– rudarsko-geološko-naftni fakultet, sveučilište u zagrebu, 1983. jurković, i. (1983): translation of some english scientific boucklet for students of geology and mining: “break of pangea” of r.s. dietz – j.c. holden (1970) and “geosynclinales”, “mountains and origin of continents” of r.s. dietz (1972).– rudarsko-geološkonaftni fakultet, sveučilište u zagrebu, 1983. jurković, i. (1982): upotreba minerala. mineralne sirovine u poljoprivredi. drago i plemenito kamenje. upotreba minerala u industriji na temelju njihovih specijalnih fizikalnih i fizičko-kemijskih svojstava. mineralne sirovine u industriji stakla, keramike i porculana [uses of the minerals. minerals used in the agriculture. precious stones the uses of minerals in the industry on the basis of their special physical and chemical properties. minerals used in the industry of glass, ceramic and porcelain – in croatian].– rudarskogeološko-naftni fakultet, sveučilište u zagrebu, 1982. jurković, i. (1982): sedimentna rudna ležišta [sedimentary ore deposits – in croatian].– skripta, rudarsko-geološko-naftni fakultet, sveučilište u zagrebu,, 1982, 1–45. jurković, i. (1958): istraživanje kristala rentgenskim zrakama [the investigation of the crystals by röntgen rays – in croatian].– skripta za studente kemije i geologije. drugo izdanje. tehnički fakultet, sveučilište u zagrebu, 1958, 1–52. jurković, i. (1948): istraživanje minerala rentgenskim zrakama [the investigation of the minerals by röntgen rays – in croatian].– skripta za studente kemije i geologije. tehnički fakultet, sve učilište u zagrebu, 1948, 1–70. jurković, i. (1946): tabelarna dioba minerala prema suhim kemijskim reakcijama (24 tabele) [tables of minerals based on dry chemical reactions (24 tables) – in croatian].– priručnik za studente kemije, geologije i rudarstva. klub studenata tehnike “niko tomić”, zagreb, 1946. jurković, i. (1946): praktikum za istraživanje minerala [practicum for the investigation of minerals – in croatian].– skripta za studente kemije, geologije i rudarstva. klub studenata tehnike “niko tomić”, zagreb, 1946., 1–157. remembrances jurković, i. (2004): in memoriam (obituary): dr. sc. jakob pamić, 10.09.1928-06.03.2004.– nafta, 55/4, 153–154. jurković, i. (2004): in memoriam (obituary): stylianos savvas augustithis (1931–2001).– ljetopis hazu za godinu 2003, 107, 415–416. jurković, i. & ščavnićar, s. (2001): styllanas savvas augustithis, životopis – znanstvena djelatnost [stylianos savvas augustithis, biography and scientific activity – in croatian].– ljetopis hazu, 104, 553–554. jurković, i. (1990): božidar zalokar. nekrolog [božidar zalokar. obituary – in croatian].– geol. vjesnik, 43, 230–231. jurković, i. & majer, v. (1985): paul ramdohr (1890–1985), nekrolog [paul ramdohr (1890–1985), obituary – in croatian].– ljetopis jazu, 89, 434–438. jurković, i. (1982): akademik stojan pavlović (1903–1981), nekrolog [academician stojan pavlović (1903–1981), obituary – in croatian].– ljetopis jazuza godinu 1981, 85, 408–410. jurković, i. (1981): nekrolog akademiku luki mariću (1899–1979) [obituary: academician luka marić (1899–1979) – in croatian].– spomenica preminulim akademicima, jazu, 10, 15–19. geologia croatica 68/2geologia croatica 170 papers related to the united nations projects jurković, i. (1968): gîtes plombo-zincifères du djebel azered, partie troisième: partie septentrionale.– monographie “prospection minérale du bassin de la foussana, tunisie centrale”. fond spécial des nations unies, new york, 1968, 181–254. jurković, i. (1968): gisements plombo-zinciferes du djebel azered. deuxieme partie, partie méridionale du djebel azered.– monographie “prospection minérale du bassin de la foussana, tunisie centrale”. fond spécial des nations unies, new york, 1968, 163–180. jurković, i. (1968): gisements plombo-zinciferes du djebel azered, tunisie. premiére partie: stratigraphie et tectonique. dolomitisation et silicification. age de minéralisation.– monographie “prospection minérale du bassin de la foussana, tunisie centrale”. fond spécial des nations unies, new york, 1968, 136–162. jurković, i. & nouvel, j. (1968): gisements plombo-barytiques de bou ghanem el guedim, tunisie.– monographie “prospection minérale du bassin de la foussana, tunisie centrale”. fond spécial des nations unies, new york, 1968, 132–135. jurković, i. (1968): gisements plombo-zincifères du djebel hamra, tunisie.– monographie “prospection minérale du bassin de la foussana, tunisie centrale”. fond spécial des nations unies, new york, 1968, 51–131. jurković, i. (1968): gîtes plombo-calaminaires d’ain nouba, tunisie.– monographie “prospection minérale du bassin de la foussana, tunisie centrale”. fond spécial des nations unies, new york, 1968, 36–50. ghozi, t. & jurković, i. (1968): gîtes plombeux de sidi bou lâaba, tunisie.– monographie “prospection minérale du bassin de la foussana, tunisie centrale”. fond spécial des nations unies, new york, 1968, 23–35. terrée, p. & jurković, i. (1968): géochimie strategique du djebel semmama, tunisie.– monographie “prospection minérale du bassin de la foussana, tunisie centrale”. fond spécial des nations unies, new york, 1968, 17–22. jurković, i. (1968): gisements de calamine ferrugineuse du plateau de bled zelfane, en tunisie centrale, afrique.– monographie “prospection minérale du bassin de la foussana”. fond spécial des nations unies, new york, 1968, 1–16. jurković, i. (1966): les pegmatites du togo central entre atakpamé et sokodé: pegmatites et aplites en liaison, avec des migmatites et anatexites du togo méridional; phenoménes du métamorphism de contact, togo (benin) afrique. lomé.– nation unies, undp, édition, new york, 1966. jurković, i. (1966): les indices de pyrite de yokélé, togo (benin), afrique.– nations unies, undp édition, new york, 1966, 1–10. available online june 19, 2015 geologia croaticageologia croatica geologia croatica 68/2 147–159 5 figs. 9 tabs. zagreb 2015 multivariate statistical analysis of urban soil contamination by heavy metals at selected industrial locations in the greater toronto area, canada  yousef h. nazzal1*, nassir s.n. al-arifi3, muhammad k. jafri3, hossam a. kishawy2, habes ghrefat3, mahmoud m. el-waheidi3, awni batayneh3 and taisser zumlot3 1 department of applied sciences & mathematics, college of arts & sciences, abu dhabi university, p.o. box 59911, abu dhabi, uae; (*corresponding author: yousef.nazal@gmail.com, yousef.nazzal@adu.ac.ae; tel. 00971509620945; fax. 0097125860183) 2 faculty of engineering and applied science, university of ontario institute of technology, 2000 simcoe street north, oshawa, ontario, l1h 7k4, canada 3 department of earth and environmental sciences,yarmouk university, irbid 21163, jordan doi:10.4154/gc.2015.10 abstract a good understanding of urban soils metal contamination and locating their pollution sources due to industrialization and urbanization is important for addressing environmental problems. urban soil samples near industrial locations in the greater toronto area (gta), ontario, canada were analyzed for metal (cr, mn, fe, ni, cu, zn, and pb) contamination. multivariate geo-statistical analysis (correlation matrix, cluster analysis, principal component analysis) was used to estimate the variability of the soil chemical content. the correlation matrix exhibits a negative correlation with cr. the principal component analysis (pca) displays two components. the first component explains the major part of the total variance and is loaded heavily with cr, mn, fe, zn, and pb, and the sources are industrial activities and traffic flows. the second component is loaded with ni, and cd, and the sources could be lithology and traffic flow. the results of the cluster analysis demonstrate three major clusters: 1) mn-zn, 2) pb-cd-cu and cr, 3) fe-ni. the geo-accumulation index (i geo) and the pollution load index (pli) were determined and show the main i geo values to be in the range of 0-1.67, indicating the studied soil samples are slightly to moderately contaminated with cr, fe, cu, zn, and cd, and moderately contaminated with pb, while ni, and mn fall into class “0”. regarding the pli, the lowest values are observed at stations 6, 7, 9, 10, 11, 12, 25, 27 and 28, while the highest values are recorded for stations 1, 5, 6, 13, 14, 16, 17, 18, 20, 22 and 24, and very high pli readings are seen for stations 5, 13, 16, 17, 18, 22 and 24. these data confirm that in addition to heavy traffic flows, the chemical and metallurgical type of industries are the major source for soil pollution in the gta. keywords: heavy metals, multivariate analysis, pollution loading index, greater toronto area 1. introduction in recent years, much concern has been expressed over the problem of urban soil contamination with heavy metals due to rapid industrialization and urbanization (sun et al., 2008). many studies indicate that urban soils are contaminated by heavy metals, and this phenomenon has been attributed mainly to modern industries, traffic and mining activities in urban areas (nazzal et al., 2012, 2014; xiaoyu li et al., 2013; de kimpe & moral, 2000; gallagher et al., geologia croatica 68/2geologia croatica 148 sources of some heavy metals in top soils, based on both visual inspection of concentration maps and quantitative analyses over varied spatial scales of the spatial variability of the elements and their relationships. they used multivariate methods to relate concentrations of heavy metals to the local geology and land use, by comparing the results of principal component analyses carried out on concentration data with the experimental indicator variogram for selected categorical information. multivariate geostatistics uses information arising from relationships among variables to improve estimations for variables and to identify the different causes of variations over different spatial scales (castrignano et al., 2009). some factors affecting soil variations exhibit short-range effects while others are important over greater distances. hence, soil variables are anticipated to correlate in a scaledependent manner, and this correlation structure of some soil variables, providing it reflects different variability sources, is important in environmental studies. such activities require a statistical approach that combines classic principal component analysis, to describe correlation structure of multivariate data sets, with geostatistics, to account for the coregionalized nature of the variables (sollitto et al., 2010). here, we apply this method to the gta, with the objective of improving understanding of the environmental impacts in that region and their causes. as part of the investigation, the authors undertook field sampling to identify sources, site-specific pollution and profiles of pollutant concentrations in the form of heavy metals and their geochemical associations. 2. materials and methods 2.1. study area as the third largest industrial area in north america, industrial entities are major contributors to the economy and employment of the gta. the varied industries are operating in this area impact air, water and soil quality. in addition, the region has dense urban traffic and its major highways (highways 401, 400 and 404, and the don valley parkway) exhibit daily traffic flows of about 920,000 vehicles (nazzal et al., 2012). toronto is located in southern ontario on the north western shore of lake ontario (fig. 1). with over 5 million residents, it is the fifth most populous city in north america. its metropolitan area with over 5 million residents is the seventh largest urban region in north america. toronto is at the heart of the greater toronto area (gta), and is part of a densely populated region in southern ontario known as the golden horseshoe, with over 8.1 million residents, representing approximately 25% of canada’s population (population of census metropolitan area, 2006). as table 1 shows the gta has industries of many types (e.g., agriculture, food, textiles, metallurgical, chemical, electronic, machinery, etc.). these industries release large amounts of solid, liquid and gaseous wastes. to identify possible sources of soil pollution in the study area, dusts and particle 2008). the concentrations of heavy metals and toxic elements in roadside soils and dust can help inform about pollution levels in urban and industrial areas since such concentrations usually reflect the extent of the emissions of these substances from anthropogenic sources (fergusson, 1990; harrison et al., 1981). lead is a particularly widespread pollutant and its presence in soils has been linked to the use of alkyl-lead compounds such as antiknock additives in gasoline, gratani et al. (1992), nazzal et al. (2014). soils along highways often have high contents of heavy metals. further, a trend has been noted towards higher concentrations of heavy metals on streets where traffic is more likely to undergo stop-start operations, e.g., at traffic lights (akhter & madany, 1993; ellis & revitt, 1982; fergusson et al., 1980); dyke et al., 1989; johnston et al., 1985; hamilton et al., 1984; howari & banat, 2001; abu-rukah, 2002; wei & yang, 2010; wei et al., 2009; dao et al., 2010; morton-bermea et al., 2009). most of these studies indicate that metal deposition peaks closest to the roadside and diminishes rapidly with increasing distance from the road. there are generally two main sources of heavy metals in the soils (li et al., 2009b) i) natural background, representing heavy metals concentrations derived from parent rocks; and ii) anthropogenic, caused by agrochemical activity, organic amendments, animal manure, mineral fertilizer, sewage sludge and industrial waste and dusts. over the last few decades, the natural input to soils of several heavy metals due to pedogenesis has been surpassed, at local through to regional and global levels, by anthropogenic inputs (facchinelli et al., 2001; nriagu & pacyna, 1988; xiaoyu li et al., 2013). recent studies of pollution along highways in the greater toronto area (gta), in ontario, canada (nazzal et al., 2012, 2014) have identified some significant environmental situations, with increased heavy metal concentrations resulting from various processes acting at different spatial scales. these variations in metal concentrations in the roadside dust and soils have both natural and anthropogenic origins. the greater toronto area is the third-largest industrial market in north america, and factories and other industrial properties are major contributors to employment and the economy. manufacturing in the gta increased at a rate of 4.6% per annum in the fourth quarter of 2013. toronto is consistently ranked near the top in terms of global competitiveness, innovation and quality of life, and possesses multisector strength, depth of talent and a driving economic and financial engine. as the business and financial capital of canada, the gta economy contributes $286 billion (approximately half of which comes directly from toronto) annually to the canadian economy. the gta has a wide range of industries and services, supporting a range of business needs. between 1990 and 2010, the region’s economy grew from $140 billion to $240 billion (in 2002 cad dollars), while ontario’s economy grew from $310 billion to $490 billion. webster et al. (1994) have applied multivariate geostatistics to provide a more objective assessment of the http://en.wikipedia.org/wiki/southern_ontario http://en.wikipedia.org/wiki/lake_ontario http://en.wikipedia.org/wiki/list_of_cities_in_north_america http://en.wikipedia.org/wiki/list_of_the_largest_urban_agglomerations_in_north_america http://en.wikipedia.org/wiki/list_of_the_largest_urban_agglomerations_in_north_america http://en.wikipedia.org/wiki/greater_toronto_area http://en.wikipedia.org/wiki/golden_horseshoe nazzal et al.: multivariate statistical analysis of urban soil contamination by heavy metals at selected industrial locations in the greater toronto area, canada geologia croatica 149 emissions are assessed. this information, with data on the geology, soils, land-use patterns, topographic environment of the area and other physical and technical conditions, allow soil pollution sources in the study area to be investigated. 2.2. geology, terrain, soils, and land use the bedrock geology of ontario is variable in lithology, structure and age, although approximately 61 percent of the province is underlain by precambrian rocks of the canadian shield (thurston, 1991). in the phanerozoic, sedimentary rocks developed in marine basins along the northern border of the shield, forming the hudson bay lowlands and in the great lakes basins in the south. the shield can be divided into three major geological and physiographic regions, with the oldest in the northwest and the youngest in the southeast. the northwestern region, known as the superior province and lying north and west of sudbury, is more than 2.5 billion years old. this region is composed mainly of felsic intrusive rocks forming the rocky severn and abitibi uplands (bostock, 1970). the central region, known as the grenville province, at 1.0-1.6 billion years old and lying to the south of sudbury, is dominated by metasedimentary rocks that form the laurentian highlands. the penokean hills, a fold belt, and the cobalt plain, an embayment, comprise the southern province, which is a narrow region approximately 1.8-2.4 billion years old extending from sault ste. marie in the west approximately to kirkland lake in the east. to the north of the shield, in the hudson bay lowlands, the bedrock is composed of carbonate sedimentary formations. these formations date primarily from the silurian period, but there are also significant parts representign the ordovician and devonian periods. other sedimentary rocks exist near ottawa, in an area referred to as the ottawa embayment, as well as throughout areas north of lakes erie and ontario (dyke et al., 1989). the clastic and marine carbonate bedrock of southern ontario is interrupted by the frontenac axis, a southern extension of the shield, which intersects the st. lawrence seaway east of kingston. the frontenac axis has different forest cover and land-use patterns compared to areas to the west or east, due to its uneven terrain and shallow acidic soils, both of which are characteristic of the canadian shield. the canadian system of soil classification agriculture canada (1987) is a standard series of orders and component groups by which soils can be identified and described. six of the soil orders in this classification predominate in ontario: organic and related organic cryosolic soils in northern parts of the province, brunisols in the northwest part of the shield and south of the shield, podzols over much of the central and southern shield, luvisols in the claybelt and over much of southern ontario, and gleysols in poorly drained areas and in the claybelt lacustrine deposits. regosolic soils are dominant only in a thin band along the southwest shore of hudson’s bay (agriculture and agri-food canada, 1996). figure 1: a map of the sampling and study location in the greater toronto area. values on horizontal axis denote latitude, and on vertical axis denote longitude. geologia croatica 68/2geologia croatica 150 table 1: industries and manufacturers in the greater toronto area (2014) (source: http://www.toronto.net/industries_and_manufacturers.html). type of industry no. of manufacturers type of industry no. of manufacturers type of industry no. of manufacturers agriculture 18 textile products 10 safety equipment 48 brick & concrete 8 wood products 41 aviation industry 11 computer equipment 37 casting, molding & machinery 35 chemical & allied products 39 electrical products 18 conveyor systems 8 drugs 2 energy 85 electronic solutions 53 factory automation 19 food production 78 engineering 84 heating & verification 22 household furniture 8 glassware & china ware 22 industrial equipment 129 industrial supplies 70 hydraulic products 11 leather clothing 7 lighting products 12 insulation 21 mining & exploration 18 medical & diagnostics 45 machinery 41 sanitation 4 paper products 17 metal working 122 telecommunications 159 stone products 32 plastic products 47 waste management 67 from the early 1990s to the early 2000s, the total area of settlement and developed land in the gta increased by 513 km2, while the areas of agricultural and naturally vegetated land decreased by 114 and 423 km2, respectively. 2.3. collection of samples a total of 30 soil samples were collected from industrial locations in the greater toronto area in august 2013. at every field station, samples were collected with a manually operated stainless steel auger, within the surface 10 cm and mainly from grassland. the soil sample raw weight was about 1 kg. 2.4. geochemical analyses the soil samples were transported to the laboratory in polyethylene bags and dried in an oven at 60 °c for 24 h. the time duration between sampling and bringing them to the lab was 24 hours. different grain size fractions were selected for the analysis of metals: <2 µm (population of census metropolitan areas, 2006); morton-bermea et al., 2009; abu-rukah, 2002) <63 µm (calmano & wellerhaus, 1982), <150 µm, and <2 mm (wong & mak, 1997). in the present study, contamination of soils with particle size fractions below 2 µm was investigated using the pipette method (gee & bauder, 1986), in which a sample is pipetted at different times and from various depths of the sample suspension in a measuring cylinder. the pipetted suspension is condensed and dried, and the mass ratio of the pipetted fraction is determined by weighing. then, 0.5 g of the pipetted fraction was digested using 4 ml of hno3 (65%), 2 ml of hf (40%), and 4 ml of hclo4 (70%). the resulting solution analyzed with an atomic absorption spectrometer (pye unicam sp9) for lead (pb), zinc (zn), cadmium (cd), nickel (ni), chromium (cr), copper (cu), manganese (mn), and iron (fe). for quality control, all soils samples were analyzed in triplicate and mean values calculated for estimation of their precision. in addition, analytical blanks were run in the same way as table 2: statistical summary of metal levels (in ppm) for the collected soil samples.   n range minimum maximum mean std. deviation variance skewness kurtosis statistic statistic statistic statistic statistic statistic statistic statistic std. error statistic std. error cr 30 1548.5 10.8 1559.3 392.9 611.9 374527 1.31 0.42 -0.25 0.83 mn 30 2277 344 2621 1047 761 579141 1.06 0.42 -0.43 0.83 fe 30 238851 16546 255398 65012 63783 4068293450 1.55 0.42 1.38 0.83 ni 30 0.7 0.10 0.80 0.22 0.177 0.03 1.76 0.42 2.94 0.83 cu 30 158.8 8.60 167.4 82.9 58. 3377 0.10 0.42 -1.60 0.83 zn 30 389.8 44.8 434.6 174.3 118.9 14155 0.76 0.42 -0.66 0.8 cd 30 0.7 0.10 0.80 .41 0.19 0.04 0.36 0.42 -0.92 0.83 pb 30 96.2 18 114.2 55.3 30.8 954 0.81 0.42 -0.67 0.83 valid n (listwise) 30                     http://www.toronto.net/industries_and_manufacturers.html nazzal et al.: multivariate statistical analysis of urban soil contamination by heavy metals at selected industrial locations in the greater toronto area, canada geologia croatica 151 the samples and concentrations were determined using standard solutions prepared with the same acid matrix to monitor the possibility of sample contamination during digestion and subsequent analysis. the absorption wavelength and detection limits, respectively, were as follows: 228.8 nm and 0.0006 ppm for cd; 240.7 nm and 0.007 ppm for co; 324.7 nm and 0.003 ppm for cu; 248.3 nm and 0.005 ppm for fe; 279.5 nm and 0.003 ppm for mn; 232.0 nm and 0.008 ppm for ni; 217.0 nm and 0.02 ppm for pb; and 213.9 nm and 0.002 ppm for zn. the accuracy of the atomic absorption spectrometer measurements was assessed by analyzing the standard reference material nist, srm 1646. the calculation of the different statistical parameters was performed using the spss (statistical program for the social sciences) software package. 3. results and discussion 3.1. general trends the average concentrations of the metals considered in the sampling in relation to the natural background values are listed in table 2. a wide range of values is observed for each metal. also, spatial distribution maps for the various analyzed samples are presented in fig. 2. a comparison of the data shows that the average concentration of the investigated heavy metals in the analyzed soil samples are in many locations, higher than their corresponding values in the average world soils (table 3). 3.2. concentrations of metals in soil samples minimum and maximum concentrations, mean values and standard deviations are presented in table 2 for each of the analyzed metals in the collected samples from the industrial areas in the gta, together with the corresponding background values. the mean concentrations for metals are as follows (in parts per million): cd (0.41), cr (392.95), mn (1047.35), fe (65.012), ni (0.22), cu (82.9), zn (174.3), and pb (55.37). in general, the concentrations of the metals vary widely in the studied locations. for some metals the mean concentrations for the soil samples collected in industrial locations are higher than their background values, suggesting that the presence of these metals in the collected samples around the gta is influenced by anthropogenic sources, such as industrial activity and traffic flows. kurtosis values (table 2) for some of the studied metals are higher than zero, indicating that the peak in the distribution is sharper than expected, chen et al. (2012). the skewness values (table 2) of some metals (fe, ni cu) are larger than unity, demonstrating that these metals positively skew towards lower concentrations (lu et al., 2009; xia et al., 2011). this observation is also confirmed by the fact that the arithmetic mean concentrations are greater than the corresponding median concentrations. as a result the geometric means for these metals provide more useful data than the arithmetic means. particular elements are discussed in detail below: 3.2.1. lead lead (pb), a naturally occurring bluish-gray metal, is found in small quantities in the earth’s crust. much of the lead in the environment is derived from human activities including fossil fuel combustion, mining and manufacturing (nazzal et al., 2012). due to health concerns, the lead content in gasoline, paint and ceramic products and pipe solder have been dramatically reduced in recent years. when released into the air, lead can travel long distances before settling to the ground and it usually sticks to soil particles once it falls onto soils (howari et al., 2004). in the study area, the pb concentration ranges table 3: average crustal abundance of and average world soils concentrations. element element average in world soils (ppm) (alloway, 1990) average crustal soils abundance (ppm) (wedephol, 1969) pb 25 12.5 cd 0.35 0.2 zn 90 70 co 15 25 ni 40 75 table 4: principal component analysis results. total variance explained component initial eigenvalues extraction sums of squared loadings rotation sums of squared loadings a total % of variance cumulative % total % of variance cumulative % total 1 5.49 68.6 68.62 5.49 68.62 68.62 5.48 2 1.52 19.0 87.70 1.52 19.08 87.70 1.55 3 .47 5.88 93.58         4 .27 3.45 97.04         5 .09 1.14 98.18         6 .07 .97 99.16         7 .05 .72 99.88         8 .009 .11 100.0         geologia croatica 68/2geologia croatica 152 figure 2: spatial distribution maps of metal concentrations (in ppm) for samples collected from different industrial locations in greater toronto. a) cr, b) cu, c) cd, d) fe, e) mn, f ) ni, g) pb, & h) zn. nazzal et al.: multivariate statistical analysis of urban soil contamination by heavy metals at selected industrial locations in the greater toronto area, canada geologia croatica 153 figure 2: continued. geologia croatica 68/2geologia croatica 154 between 18-114 ppm. the critical concentration in soils of lead is between 100 and 400 ppm, and the global measured lead concentration in surface soils is estimated as 25 ppm (alloway, 1990) (table 3). locations 5, 14, 17, 21 and 23 exhibit concentrations of more than 100 ppm and these values depend on such factors as industry type and size, traffic flows, prevailing winds and humidity (nazzal et al., 2014). 3.2.2. zinc poor format here zinc, a heavy metal essential for life, acts biologically as a catalytic or structural component of numerous enzymes involved in energy metabolism and in transcription and translation (alloway, 1990); forstner & wittman, 1983). zinc enters air, water and soils partly as a result of natural processes but mostly due to human activities (e.g., mining, zinc purification, steel production, burning of coal and wastes (nazzal et al., 2012). the zinc concentration in the investigated soil samples ranges from 45 to 435 ppm (table 2). most of the locations (13, 14, 15, 16, 17, 18, 20, 22, 24, and 29) exhibit higher values than the average world soil concentration value of 90 ppm (alloway, 1990). locations 1, 5, 6, 7, 8, 9, 10, 11, 22, 24 and 29 exhibit maximum values exceeding 200 ppm. according to jiries et al. (2001), and ellis & revitt (1982), zinc may be derived from mechanical abrasion and oil leaks from vehicles, so high concentrations in the study area are likely to be related to high traffic flows into and out of the industrial units. 3.2.3. cadmium cadmium has no biological functions and is highly toxic. environmental pollution from cadmium has increased rapidly in recent decades due to the rising use of cadmium by industry (alloway, 1990). the average natural abundance of cadmium in the earth’s crust is normally reported to be 0.1-0.5 ppm, but much higher and much lower values have also been cited, depending on various factors (howari et al., 2004). in the study area, the average concentration of cd ranges between 0.1 and 0.8 ppm, with locations 1, 5, 6, 8, 13, 14, 15, 16, 17, 18, 20, 22 and 29 exhibiting higher than the permissible values (0.1–0.5 ppm). the presence of cd in the studied samples is believed to be associated with tyre wear, a phenomenon described by ellis & revitt (1982). 3. 3. multivariate geostatistics geostatistical methods are useful when data are normally distributed around a stationary mean and variances do not vary significantly spatially (soumya et al., 2013). significant deviations from normality and stationary means can cause problems. initial plotting of a histogram of the data facilitates the checking of normality and position of the data values in space to determine any significant trends. data matrices were evaluated through principal component analysis (pca) allowing the summarized data to be further analyzed and plotted. generally, three approaches are used: catell sree test, (cattell, 1966), kaiser criterion (kaiser & rice, 1974), and variance explained criteria (percentage of variance). we use the scree plot method to assess the number of principal components (pcs) to be obtained (fig 3). the plotting of eigenvalues (x axis) against pc numbers (y axis) provides insight into the maximum number of components to be extracted. according to the eigenvalues 5.490 and 1.527 respectively (table 4), two principal components pc1 and pc2 are selected (table 5) which explain 68.6 % and 19.1 % respectively of the total variance, (table 4). the application of the rotation matrix method leads to an increase in pc1 and a reduction in pc2 (table 5). the application of kaiser-meyer-olkin (kmo) and bartlett’s test of sphericity gives values of 0.82 and 315.9 (table 6), respectively, and the significance level is <0.001. these values demonstrate that factor analysis for this study is suitable. factor 1 should be industrial and traffic flow, which is also evident from the presence of various metal processing figure 3: shows scree plot. nazzal et al.: multivariate statistical analysis of urban soil contamination by heavy metals at selected industrial locations in the greater toronto area, canada geologia croatica 155 industries in the area (i.e., the gta has many metallurgical and chemical industries as shown in table 1). the source of factor 2 is anthropogenic and natural, including weathering and erosion. the correlation matrix for heavy metals in analyzed soil samples from the gta is provided in table 6. the results here shows that, when p is 0.05 then the result is significant at the 95 % confidence level but highly significant would be p 0.01 (99%) confidence level. a positive correlation between the metals is shown in table 7. cr is highly positively correlated with mn, fe, cu, zn, cd and pb. mn positively highly correlated with fe, cu, zn, cd and pb. fe is highly positively correlated with cu, zn and pb. cu is positively correlated with zn, while zn is positively correlated with cd and pb. this highly positive correlation among metals may suggest a common origin, such as traffic flow or industrial activity in the study area. pca is applied to assist in identifying sources of pollutants. by extracting the eigenvalues from the correlation matrix, the number of significant factors and the presence of variance explained by each of them, are calculated using the software package spss 15. table 4 displays two components. the first explains the majority of the total variance and is loaded heavily with cr, mn, fe, zn and pb. the source of the component may be industrial activities and traffic flows. this observation is also evident from the presence of various metal processing industries in the study area in addition to traffic flow. component 2 is loaded with ni and cd, the source of which could be lithology and traffic flow. before performing a cluster analysis, the variables are standardized by means of z-scores; then euclidean distances for similarities in the variables are calculated. finally hierarchical clustering is determined by applying ward’s method with the standardized data set. the results of the cluster analyses for the variables are shown in fig. 4 as a dendrogram. this figure displays three major clusters, mn–zn, pb–cd–cu – cr and fe–ni, in agreement with pca results. table 5: component rotated matrix. component 1 2 cr 0.98 -0.11 mn 0.96 0.08 fe 0.95 -0.03 ni -0.13 0.94 cu 0.77 -0.02 zn 0.92 0.23 cd 0.64 0.63 pb 0.88 -0.41 extraction method: principal component analysis. rotation method: oblimin with kaiser normalization. table 6: kaisermeyerolkin (kmo) significance test. kmo and bartlett’s test kaiser-meyer-olkin measure of sampling adequacy 0.82 bartlett’s test of sphericity approx. chi-square 315.9 df 28 sig. .00 table 7: correlation matrix.   cr mn fe ni cu zn cd pb correlation cr 1.00 0.96 0.95 -.16 0.67 0.87 0.56 0.90 mn 0.96 1.0 0.91 0.002 0.70 0.91 0.69 0.79 fe 0.95 0.91 1.0 -0.07 0.63 0.85 0.59 0.85 ni -0.16 0.002 -0.07 1.0 -0.07 0.10 0.42 -0.41 cu 0.67 0.70 0.63 -0.07 1.0 0.70 0.45 0.61 zn 0.87 0.91 0.85 0.10 0.70 1.0 0.80 0.69 cd 0.56 0.69 0.59 0.42 0.45 0.80 1.0 0.31 pb 0.90 0.79 0.85 -0.41 0.61 0.69 0.31 1.0 sig. (1-tailed) cr   0.0 0.0 0.19 0.0 0.0 0.001 0.0 mn 0.0   0.0 0.49 0.0 0.0 0.0 0.0 fe 0.0 0.0   0.35 0.0 0.0 0.0 0.0 ni 0.19 0.49 0.35   0.34 0.28 0.009 0.012 cu 0.0 0.0 0.0 0.34   0.0 0.005 0.0 zn 0.0 0.0 0.0 0.28 0.0   0.0 0.0 cd 0.001 0.0 0.0 0.009 0.005 0.0   0.04 pb 0.0 0.0 0.0 0.012 0.0 0.0 0.045   geologia croatica 68/2geologia croatica 156 3.4. geo-accumulation index the geo-accumulation index (igeo), introduced by muller (1979), is used to assess the extent of pollution in the analyzed soil samples from industrial locations in the gta, and can be calculated as follows: igeo = log2 (cn/1.5bn) here, cn is the measured concentration of metal n in the soils, 1.5 is used as a factor to minimize possible variations in the background values, and bn is the geochemical background value of metal n. geochemical background values for the studied metals in soil media proposed by alloway (1990) were used as bn. mean values of igeo for each element are shown in table 8. based on the igeo data and muller’s geo-accumulation index listed in table 9, the main igeo values are in the range of 0 to 1.67. the igeo values indicate that the soil samples for the studied industrial locations in the gta are slightly/moderately contaminated with cr, fe, cu, zn and cd, and moderately contaminated with pb. for ni and mn, igeo falls in class 0, indicating that no pollution from these metals was recognized in the studied samples. these results indicate that the soil samples for the studied industrial locations in the gta are enriched with potentially toxic metals from anthropogenic sources such as industry and traffic flow. 3.5. pollution load index the contamination extent by metals in soils is assessed using the pollution load index (pli) (tomlinson et al., 1980; selvaml et al., 2012) with heavy metal data and world shale average values (turekian & wedepohl, 1961) of the metals, (badr et al., 2009; ray et al., 2006). figure 4: hierarchical cluster analysis dendrogram. table 8: geo-accumulation index (igeo) for contamination levels (adapted from muller, 1981). igeo class igeo value contamination level 0 igeo ≤ 0 uncontaminated 1 0 < igeo < 1 uncontaminated/moderately contaminated 2 1 < igeo < 2 moderately contaminated 3 2 < igeo < 3 moderately/strongly contaminated 4 3 < igeo < 4 strongly contaminated 5 4 < igeo < 5 strongly/extremely contaminated 6 5 < igeo extremely contaminated table 9: geo-accumulation index (igeo) and contamination levels (in parentheses) for selected metals in greater toronto area soil samples. metal igeo contamination level cr 0.99 uncontaminated/moderately contaminated mn -0.75 uncontaminated fe 0.27 uncontaminated/moderately contaminated ni -7.64 uncontaminated cu 0.93 uncontaminated/moderately contaminated zn 0.50 uncontaminated/moderately contaminated cd 0.65 uncontaminated/moderately contaminated pb 1.67 moderately contaminated nazzal et al.: multivariate statistical analysis of urban soil contamination by heavy metals at selected industrial locations in the greater toronto area, canada geologia croatica 157 the pli provides a summative indication of the overall level of heavy metal pollution in a sample. the pli was calculated for the investigation area for eight metals, considering the lowest toxicity of the most abundant metals. pli values are calculated using the equation pli = 1 2 3⋅ ⋅ ⋅n cf cf cf ...cfn here, cf denotes the contamination factor and n is the number of metals. the contamination factor is calculated as follows: metal concentration in sample cf = shale value / background of the metal the pli values for all sites are found to range from 0.03.6 (fig. 5). the lowest pli values occurred at stations 6, 7, 8, 9, 10, 11, 12, 25, 26, 27 and 28, and the highest at stations 1, 5, 6,13,14,16, 17, 18, 20, 22 and 24, while stations 5, 13, 16, 17, 18, 22 and 24 exhibit very high pli values. this confirms, as discussed earlier, the importance of the type of industries (especially metallurgical and chemical ones) in the area besides high traffic flows. most of the industrial locations considered are close to the busiest highway in north america (highway 401). 4. conclusion heavy metal soil concentrations for industrial locations in the greater toronto area (gta), ontario, canada have been investigated. the mean concentrations (ppm) for the metals assessed observed are cd (0.41), cr (392.95), mn (1047.35), fe (65012), ni (0.22), cu (82.9), zn (174.3) and pb (55.37). the use of a correlation matrix, cluster analysis and principal component analysis to estimate the variability of the chemical content of the soil reveals the impact of industrial and anthropogenic activities on heavy metal concentrations in the soils of the study area. the geo-accumulation index and pollution load index results show that the main geo-accumulation index values are 0-1.67, suggesting that soil samples for the studied industrial locations in the gta are slightly – moderately contaminated with cr, fe, cu, zn and cd, and moderately contaminated with pb, while ni and mn fall in class 0. the pollution loading index values are lowest at stations 6, 7, 9, 10, 11, 12, 25, 27 and 28, and highest values at stations 1, 5, 6, 13, 14, 16, 17, 18, 20, 22 and 24, while stations 5, 13, 16, 17, 18, 22 and 24 exhibit very high pli values. it is concluded that the type of industry, especially those related to metallurgical and chemical activity, in the study area as well as traffic flows, are the main sources for the esnsuing soil pollution. acknowledgment the authors would like to extend their sincere appreciation to the deanship of scientific research at king saud university for its funding this research group no. (rg 1435-008). references abu-rukah, y.h. (2002): a study of soils along the amman aqaba highway contamination with heavy metal.– freiberger forschungshefte, geowissenschaften, c49, 53–62. akhter, m.s. & madany, i.m. (1993): heavy metals in street and house dust in bahrain.– water, air, and soil pollution, 66, 111–119. agriculture and agri-food canada (1996): soil landscapes of canada. version 2.2, national soil data base.– ottawa, ontario: agriculture and agri-food canada. agriculture canada (1987): the canadian system of soil classification.– 2nd ed. publication no. 1646. ottawa, ontario: agriculture canada, research branch. figure 5: pollution load index calculated for different locations in the study area. geologia croatica 68/2geologia croatica 158 alloway, b.j. (1990): heavy metals in soils.– glasgow: blackie and sons. badr, n.b.e., el-fiky, a.a., mostafa, a.r. & al-mur, b.a. (2009): metal pollution records in core sediments of some red sea coastal areas, kingdom of saudi arabia.– environmental monitoring assessment, 155, 509–526. bostock, h.s. (1970): physiographic subdivisions of canada.– in: douglas, r.j.w. (ed.): geology and economic minerals of canada. economic geology report no. 1. ottawa, ontario: geological survey of canada, 10–30. calmano, w. & wellerhaus, s. (1982): dredging of contaminated sediments in weser estuary: chemical forms of some metals.– environmental technology letters, 3, 199–208. cattell, r.b. (1966): the scree test for the number of factors.– multiple behavior research, 1, 245–276. castrignano, a., costantini, a.c., barbetti, e.r. & sollitto, d. (2009): accounting for extensive topographic and pedologic secondary information to improve soil mapping.– catena, 77, 28–38. chen, x., xia, x.h., zhao, y. & zhang, p. (2010): heavy metal concentration in roadside soils and correlation with urban traffic in beijing, china.– journal of hazardous materials, 181, 640–646. chen & dongmei (2010): geospatial analysis modelling of urban structure and dynamics.– springer e book, springer. chen, x., lu, x., & yang, g. (2012): sources identification of heavy metals in urban topsoil from inside the xi'an second ring road, nw china using multivariate statistical methods. catena, 98, 73–78. dao, l., morrison, l. & zhang, c. (2010): spatial variation of urban soil geochemistry in a roadside sports ground in galway, ireland. science of the total environment, 408, 1076–1084. de kimpe, c.r. & morel, j.l. (2000): urban soil management, a growing concern. soil science, 165, 31–40. dyke, a.s., vincent, j.s., andrews, j.t., dredge, l.a. & cowan, w.r. (1989): the lauren tide ice sheet and an introduction to the quaternary geology of the canadian shield.– in: futton, r.j. (ed.): quaternary geology of canada and greenland. geology of canada, publication no. 1 (178–189). ottawa: ontario geological survey of canada. ellis, j.b. & revitt, d.m. (1982): incidence of heavy metals in street surface sediments: solubility and grain size studies.– water, air, and soil pollution, 17, 87–100. facchinelli, a., sacchi, e. & mallen, l. (2001): multivariate statistical and gis based approach to identify heavy metal sources in soils.– environmental pollution, 114, 313–324. fergusson, j.e., hayes, r.w., yong, t.s. & thiew, s.h. (1980): heavy metal pollution by traffic in christchurch, new zealand: lead and cadmium content of dust and soil, and plant samples.– new zealand journal of science, 23, 293–310. fergusson, j.e. (1990): the heavy elements: chemistry, environment impact and health effects, vol. 9.– pergamon press, oxford. forest landscape ecology program, ontario ministry of natural resources (1996): surficial geology of ontario: digital database and viewing software [cd-rom]. sault ste. marie, ontario: ontario forest research institute, ontario ministry of natural resources. forstner, u. & wittman, g.t. (1983): metal pollution in the aquatic environment.– berlin-springer. gallagher, f.j., pechmann, i., bogden, j.d., grabosky, j. & weis, p. (2008): soil metal concentration and vegetative assemblage structure in an urban brownfield.– environmental pollution, 153, 351–361. gee, g.w. & bauder, j.w. (1986): particle-size analysis.– in: klute, a. (ed.): methods of soil analysis, part 1. american society of agronomy, madison, 383–412. gratani, l., taglioni, s. & crescente, m.f. (1992): the accumulation of lead in agriculture soil and vegetation along a highway.– chemosphere, 24, 941–949. kaiser, h.f. & rice, j. (1974): little jiffy, mark iv educ. psychological measurement, 34, 111–117. hajji kolsi, s., bouri, s., hachicha, w. & ben dhia, h. (2013): implementation and evaluation of multivariate analysis for groundwater hydrochemistry assessment in arid environment: a case study of hajeb elyoun-jelma, central tunisia.– environmental earth sciences, 70, 2215–2224. hamilton, r.s., revitt, d.m. & warren, r.s. (1984): levels and physicochemical associations of cd, cu, pb and zn in road sediments.– science of the total environment, 33, 59–74. harrison, r.m., laxen, d.p.h. & wilson, s.j. (1981): chemical association of lead and zinc in street dust and road side soils.– environ. sci. technol., 15, 1378–1381. howari, f.m. & banat, k.m. (2001): assessment of fe, zn, cd, hg, and pb in the jordan and yarmouk river sediments in relation to their physicochemical properties and sequential extraction characterization.– water, air, and soil pollution, 132, 43–59. howari, f.m., abu-rukah, y. & goodell, o.c. (2004): heavy metal pollution of soils along north shauna-aqaba highway, jordan.– int. j. environment and pollution, 22, 597–607. ghrefat, h.a., abu-rukah, y. & rosen, m.a. (2011): application of geoaccumulation index and enrichment factor for assessing metal contamination in the sediments of kafrain dam, jordan.– environmental monitoring and assessment, vol. 178, 95–109. li, j.l., he, m., han, w. & gu, y.f. (2009b): analysis and assessment on heavy metal sources in the coastal soils developed from alluvial deposits using multivariate statistical methods.– journal of hazardous materials, 164, 976–981. lu, x.w., wang, l.j., lei, k., huang, j.m. & zhai, y.x. (2009): contamination assessment of copper, lead, zinc, manganese and nickel in street dust of baoji, nw china.– journal of hazardous materials, 161, 1058–1062. jiries, a.g., hussein, h.h. & halash, z. (2001): the quality of water and sediments of street runoff in amman, jordan.– hydrological processes, 15, 815–824. johnston, r.w., ralph, j. & wisen, s. (1985): the budget of pb, cu and cd for a major highway.– science of the total environment, 46, 137–145. morton-bermea, o., alvarezl, e., gonzalez-hernandez, g., romero, f., lonzano, r. & beramendi-orosco, l.e. (2009): assessment of heavy metal pollution in urban topsoil's from three metropolitan areas of mexico city.– journal of geochemical exploration, 101, 218–224. muller, g. (1979): schwermetalle in den sedimenten des rheins – veränderungen seit 1971. umschau, 24, 778–78. nazzal, y., rosen, m.a. & al-rawabdeh, am. (2012): assessment of metals pollution in urban road dusts from selected highways of the greater toronto area in canada.– environ monit assess j, springer. doi: 10.1007/s10661-012-2672-3. nazzal, y., habes, g. & rosen, m.a. (2014): application of multivariate geostatistics in the investigation of heavy metal contamination of road side dusts from selected highways of the greater toronto, canada.– j. environ. earth sci., 71, 1409–1419. nriagu, j.o. & pancyna, j.m. (1988): quantitative assessment of worldwide contamination of air, water and soils by trace metals.– nature, 133, 134–139. population of census metropolitan areas (2006): census boundaries. statistics canada. http://www40.statcan.ca/l01/ cst01/ demo05a-eng.htm. retrieved 2010–03–02. nazzal et al.: multivariate statistical analysis of urban soil contamination by heavy metals at selected industrial locations in the greater toronto area, canada geologia croatica 159 ray, a.k., tripathi, s.c., patra, s. & sarma, v.v. (2006): assessment of godavary estuarine mangrove ecosystem through trace metal studies.– environmental international, 32, 2190–223. selvam, a.p., priya, l.s., banerjee, k.g., hariharan, g., purvaja, r. & ramesh, r. (2012): heavy metal assessment using geochemical and statistical tools in the surface sediments of vembanad lake, southwest coast of india.– environmental monitoring and assessment, 184, 5899–5915. sollitto, d., romic, m., castrignano, a., romic, d. & bakic, h. (2010): assessing heavy metal contamination in soils of zagreb region (northwest croatia) using multivariate geostatistics.– catena, 80, 182–194. sun, l.v., yang, x.b., wang, n.q. & chen, s. (2008): spatial distribution of cd, and cu, in soils in shenyang zhangshi irrigation area (szia).– china journal of zhejiang university, science, b, 9, 271–278. tomlinson, d.l., wilson, j.g., harris, c.r. & jeffrey, d.w. (1980): problems in the assessment of heavy metal levels in estuaries and the formation of a pollution index.– helgolander meeresuntersuchungen helgolander meeresunters, 33, 566–575. thurston, p.c. (1991): geology of ontario: introduction.– in thurston, p.c., williams, h.r., sutcliffe, r.h. & scott, g.m. (eds.): geology of ontario, special volume no. 4, 3–26. toronto, ontario geological survey. turekian, k.k. &wedepohl, k.h. (1961): distribution of the elements in some major units of the earth's crust.– geological society of america, 72, 175–192. webster, atteia, o. & dubois, j.p. (1994): coregionalization of trace metals in the soil in the swiss jura.– eur. j. soil sci., 45, 205–218. wedepohl, k.h. (1969): composition and abundance of common igneous rocks. in: wedepohl, k.h. (ed.): handbook of geochemistry, , vol. i., 227–249. berlin-heidelberg-new york: springer 1969. wei, b. & yang, l. (2010): a review of heavy metal contamination in urban soils, urban roadside and agricultural soils from china.– microchemical journal, 94, 99–107. wei, b., jiang, f., li, x. & mu, s. (2009): spatial distribution and contamination assessment of heavy metals in urban road dusts from urumqi, nw china.– microchemical journal, 93, 147–152. wong, j.w.c. & mak, n.k. (1997): heavy metal pollution in children playgrounds in hong kong and its health implications.– environmental technology, 18, 109–115. xia, x., chen, x, liu, r. & liu, h. (2011): heavy metals in urban soils with various types of land use in beijing, china.– journal hazardous materials, 186, 2043–2050. xiauyu, l., lijuan, l., yugang, w., geping, l., xi, c., xiaoliang, y., myrna, h.p.h., ruichao, g., houjun, w., jiehua, c. & xingyuan, h. (2013): heavy metal contamination of urban soil in an old industry city (shenyang) in northeast china.– geoderma, 192, 50–58. manuscript received july 20, 2014 revised manuscript accepted april 24, 2015 available online june 16, 2015 2020 | 73/2 | 107–118 | 6 figs. | 3 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction worldwide, approximately two billion people depend on groundwater for their potable water supply, out of which almost 700 million are consumers of water originating in karst aquifers (stevanović, 2019). a large proportion of groundwater is also tapped from 265 aquifers that cross the political boundaries of two or more countries (world water council, 2010). in the last few decades, sustainable water development and the demand for equitable sharing of water resources were included in numerous technical and legislative documents, articles and projects dealing with transboundary groundwater (eckstein & eckstein, 2005; puri & aureli, 2005; puri & struckmeier, 2010). the requirement for equitable and reasonable exploitation of transboundary groundwater is identified in articles 4 and 5 of the law of transboundary aquifers, drafted by the un international law commission and annexed to a united nations general assembly (unga) resolution (unga, 2008). the special interest of european countries in groundwater protection is quite understandable – more than two thirds of eu member states use groundwater for more than 50% of their potable water supply, while some – including austria or denmark – use nothing but groundwater. the eu water framework directive (wfd) adopted by the european commission (ec) in 2000 (ec, 2000) indicates river basin management plans (rbmp) as the main documents to be prepared for water management at the river basin level and provides several guidance documents for groundwater quantity and quality assessment and the organisation of monitoring. however, not many documents and papers deal with the methodology of how to achieve and define the amount of water to be equally or proportionally shared and sustainably used, or how and where to organise monitoring and prevent precious groundwater from deteriorating or becoming polluted. in addition, due to the complexity and sensitivity of groundwater as an invisible resource, the obtained results are not always accurate or satisfactory, or easily understandable to those responsible for water management. this is especially the case in geologically complex and heterogenous systems such as karst. a methodology for assessing the pressures on transboundary groundwater quantity and quality – experiences from the dinaric karst zoran stevanović* & veljko marinović1 1 university of belgrade – faculty of mining and geology, centre for karst hydrogeology, department of hydrogeology, djušina 7, 11000 belgrade, serbia; (*corresponding author: zstev_2000@yahoo.co.uk) doi: 10.4154/gc.2020.08 abstract a relatively novel and abridged methodology for assessing the quantity and quality status of groundwater bodies has been applied in the dinaric karst of se europe. validation of pressure on quantity is based on groundwater budgeting and the correlation of available groundwater reserves and projected water demands, while pressure on quality is estimated by gis-created maps: vulnerability – hazard – risk. the results obtained from the studied groundwater bodies indicate mostly low pressure on water quantity, but increased risk from diffuse and point pollution sources. the application of methods is possible in many transboundary and inner aquifer systems even in geologically complex environments where there is insufficient monitoring data on the groundwater regime. the study area is a “classical” dinaric system (dinarides), an elongate, south european orogenic belt of the alpine mountain chain (alpides), oriented nw – se and running parallel to the adriatic sea. the system, in which the presence of soluble carbonate rocks – karst happens to be dominant, extends from the carso area in italy through the countries of the former yugoslavia (slovenia, croatia, bosnia and herzegovina, montenegro, serbia, north macedonia), ending in the albanian alps (stevanović et al., 2016). that is the region where a new scientific discipline – karstology was born as a result of studies by jovan cvijić (1893). later works on the dinaric karst by herak (1972), mijatović (1984), bonacci (1987, 2014), milanović (2005) and many other authors helped to better understand the complex groundwater distribution in this “classical” highly developed karst, one of the world’s largest (ford & williams, 2007). in the last decade, the current authors have completed several projects and studies in the dinaric region of se europe for the purpose of preparing a basis for rbmps or improving groundwater monitoring (stevanović & dokmanović, 2015; stevanović et al., 2015; stevanović & marinović, 2016). this article is an attempt to present previously unpublished results on a relatively simple and technically unpretentious methodology for groundwater assessment especially in complex karst terrains. the idea was to enable water managers and practitioners in the countries undergoing the eu accession process, such as bosnia & herzegovina, serbia or montenegro, to better understand the functionality of aquifer systems and facilitate the implementation of eu wfd. although the methodology is primarily developed for transboundary aquifers, such as those that were prioritised in the preparation of rbmps, the same approach can also be applied to inner aquifer systems. 2. materials and methods while in many countries of the world groundwater happens to be something that is ‘out of sight, out of mind’, the eu is definitely the world’s leader in recognising the importance and defining/implementing a strategy for its sustainable development. the wfd provides general guidelines for delineation and characterisation of article history: manuscript received january 24, 2020 revised manuscript accepted may 13, 2020 available online june 29, 2020 keywords: transboundary aquifer, karst, vulnerability, hazard, risk, dinaric region mailto:zstev_2000@yahoo.co.uk g eo lo gi a c ro at ic a geologia croatica 73/2108 groundwater bodies (gwb as the management unit), and for moni­ toring water quality and quantity. the “daughter” groundwater directive (2006/118/ec) (ec, 2006), on the other hand, sets out criteria for assessing the chemical status of groundwater, as required by article 17.2a of the wfd. given that eu member states are characterised by different geology and hydrogeology, and consequently by varying water quality, a set of additional documents the common implementation strategy (cis) for the water framework directive was prepared with the aim of establishing the common criteria and approach in the process of characterisation and assessment of groundwater bodies throughout europe (ec, 2007, 2009). however, it is also true that a framework package allows much flexibility, as well as the adaptation of required gwb status assessments to the local circumstances and specificities. for instance, the concept that each gwb that supplies more than 50 people and where the abstraction is larger than 10 m3/day should be studied and monitored is impracticable in the countries of se europe. if such a criterion was to be deliberately applied, thousands of groundwater bodies would have had to be delineated in certain groundwater­rich countries, such those in the dinaric region. therefore, at the country level, or at the level of large or medium river basins, delineation of gwbs with considerable surface or their grouping represents a more feasible solution for the characterisation process than studying each small unit separately. in the last few decades, geographical information systems (gis) have been increasingly used in the geosciences (bedell, 1995; chang, 2008; worboys & duckham, 2004). a combination of remote sensing and the existing topographic, geological, pedological, land use and other maps makes it possible to obtain general information about the terrain and its characteristics and facilitate the creation of hydrological and hydrogeological models and water resources management (milanović et al., 2010). putting all the information that was collected in such a way together with the data obtained from additional field surveys contained in the gis database offers a great opportunity for various additional analyses that could be performed at a regional scale by mighty gis extensions. along with geospatial data, the data on groundwater quantity and quality deposited in specially designed water information systems (wis) enable easy data manipulation, decision making, reporting and public participation in water management (esri inc. 2003; wise gis, 2016). as suggested by the global water partnership and international network of basin organizations (gwb/inbo) (gwb/inbo 2012), the development of coherent and integrated water resource management, as well as wis as its essential tool, is fundamental if we wish to ensure sustainable water resources and appropriate socioeconomic development. wis validated data must constitute an objective basis for discussion, negotiation, decision-making and assessment of the actions taken. the methodology for the assessment of status and pressures on groundwater which was used in several of the aforementioned regional and transboundary projects carried out in dinaric karst is in fact the modified and further developed approach of wfd, with gis as the main explanatory tool. also, the grouping of gwbs was applied deliberately. 2.1. methods for assessing pressure on groundwater quantity the parameters of risk assessment of the quantitative status are either the groundwater level or the estimated water budget (balance) of the groundwater body. according to annex v, item 2.1.1 of the wfd, good quantitative status is identified when the groundwater level in the groundwater body is such that available groundwater resources are not exceeded by the long-term annual average rate of extraction. this is a highly relative assessment that does not consider exact values, which is therefore sometimes understood by decision makers from the water or ecology sectors quite restrictively; namely that exploitation of groundwater is limited, and there is a requirement that it be completely covered by recharge throughout the entire period of water extraction. this could mean that no depletion in the aquifer would be allowed, not even for a short period of time. the other, more “flexible” concept allows only temporary depletion and fast compensation for extracted waters. the issue of allowed water exploitation rate is closely linked with the “safe yield” concept, which was imposed for the first time by meinzer (1920). the recent and – we could say – modern approach was introduced by custodio (1992), margat (1992), burke & moench (2000) and several other hydrogeologists. over­abstraction should not be defined in terms of variation of water table and its temporary depletion within an aquifer system, especially one that is as dynamic as that of a karst aquifer. estimation of over­abstraction can be much more reliable if a multiannual balance is used, and the ratio between recharge and abstraction should be evaluated over many years instead of just one or no more than a few (burke & moench, 2000; stevanović, 2015). in situations when monitoring of the groundwater regime is not systematically applied and does not cover all aquifer systems as in the case of the dinaric karst, the water budget (balance) assessment is a more feasible option than water level observation when evaluating the quantitative pressure on gwbs. at the global scale, there are several initiatives – such as the activities of the unesco­ihp programme – that are aimed at developing water resources assessments and water budgets. the atlas of world water resources was developed as part of this programme back in the 1970s, including guidelines for conducting water resources assessment. margat & van der gun published their work entitled groundwater around the world (2013), which included groundwater budgeting, and fao/aquastat1 and the world meteorological organisation’s (wmo) commission for hydro­ logy2 (chy) produced a compilation of water budgets. at the eu scale, the european environment agency (eea) has worked in recent years on physical water budgets at the catchment scale. to support the creation of rbmps, including the planning processes and the implementation of the wfd in the eu, the european commission (ec) developed the guidance for water budgeting (ec, 2015). this document focuses on the application of water budgets (balances) as a “coherent framework to cross­ evaluate the information on drivers, pressures and impacts on water quantity (including the coherence between water extraction and water recharge, water flows between water bodies/catchments, storage changes over time, etc.) and providing a sound basis for the quantitative management of water resources” (ec, 2015, p.6). however, the eu guidance for water budgeting (ec, 2015) does not fully recognise the specificity of karstic aquifers and the water budget methodology needed for this sort of aquifer system, dominant in many alpine and dinaric countries of se europe. in recent projects that were completed in the dinaric re 1 (http://www.fao.org/nr/aquastat/en) 2 (http://www.wmo.int/pages/prog/hwrp/chy/) http://www.fao.org/nr/aquastat/water_use/index.stm http://www.wmo.int/pages/prog/hwrp/chy/ g eologia c roatica zoran stevanović & veljko marinović: a methodology for assessing the pressures on transboundary groundwater quantity and quality ... 109 gion (stevanović & dokmanović, 2015; stevanović et al. 2015; stevanović & marinović, 2016), to assess the quantitative status, climatic and hydrological parameters taken from the database of the national hydrometeorological service or registered in the field during the initial characterisation of gwbs and their catchments, were compared with the historical data on water extraction (springs and wells) of delineated gwbs. data on the groundwater levels of dug or drilled wells and their trends were also taken into consideration as controlling indicators of sustainable water use. the main component of a water budget is ief (effective infiltration of rainfall into the ground, as aquifer’s recharge). ief fluctuates throughout the year and depends on numerous factors, such as vegetation season (interception intensity), snow and ice cover, actual deficit of soil moisture, groundwater depth, rainfall intensity, air temperature, winds and so on; however, for our analyses it was necessary to average the ief at the annual level (long-term annual recharge, lta). experiences in determining ief in dinaric karst are also discussed by radulović, 2000; milanović, 2005; radulović m.m., 2012; stevanovic et al. 2016. in general, dynamic (replenishable) groundwater (gw) reserves in a gwb could be roughly equalised to ief. in karst terrains and aquifers, ief can be evaluated based on the total average springs’ discharge and variation of storage. in intergranular aquifers, however, another approximate parameter can be introduced based on the results of conducted field tests or modelling: potential extraction per kilometre of length of alluvial aquifer along the riverside. to determine the amount of water that can be sustainably used as exploitable groundwater reserves (qexpl), groundwater needed for dependent eco systems in the form of ecological flow (qeco) should be subtracted from dynamic reserve (qdyn): qexpl = qdyn – qeco (1) therefore, the total minimal discharge of springs of one gwb could be considered the ecological flow, while the average total discharge via springs could be approximated as dynamic groundwater reserve. in order to verify the correctness of such an assessment, we can also compare the results obtained from the separation of hydrographs in which river baseflow supposedly corresponds relatively well with dynamic reserves. one of the prerequisites for such equivalency is to properly determine the boundaries of the river basin, which is not an easy task in highly karstified terrains. in terms of pressure, relevance should be given to these potentially exploitable gw reserves and the relation on annual basis between them and the total of extracted (or demanded) waters: pquant = ∑qextr vs. ∑qexpl (2) where pquant denotes quantitative pressure on groundwater body; qextr denotes total extracted waters; qexpl denotes exploitable groundwater reserves. this two­step approach is adequate for two reasons: first, it considers ecological demands, and second, in relatively waterrich countries with a small extraction of groundwater there is no need to use static water reserves, (accumulated in deeper aquifer parts as non­renewable stock), except in very rare cases (during extreme droughts) and when their rapid replenishment during periods of flooding is ensured (stevanović, 2015). when assessing quantitative pressure on gwb by comparing potentially exploitable and actually utilised resources, we often overlook the fact that most of the utilised water will be returned to the ground or to the water recipients. the only exception is the transfer of water over long distances out of the concerned gwb or basin. this means that if the return flow, either from the municipal sewage system or from irrigation, is in the same gwb, the ecological flow will be supported by re­infiltrated used waters. the quality of these waters is another aspect that requires attention. in order to obtain a realistic view of the potential of, and not only the actual pressure on gwb, as well as also “to be safe”, the actual extraction can be replaced by projected water demands for the determined period of time. there are several possible approaches to defining the pressure categories (at risk or not at risk) and they greatly depend on water availability. considering the fact that almost all of the studi ed karstic gwb are characterised by specific yield greater than 20 l/s/km2, and that dinaric karst countries regularly utilise less than 5% of their water potential (fao aquastat, 2018), we may declare them as water-rich countries, and impose limits which are more restrictive than in some arid countries, where humanitarian aspects must also be considered (stevanović, 2018). the criterion “percentage of” should thus be adapted to local circumstances; still, wherever possible, it should not change within the same river basin. as an example, the following pressure categories and limits can be imposed in water-rich countries: – no pressure, when gw extraction (qextr) < 33 % of gw exploitable reserves (qexpl); – no pressure (but potentially under pressure3), when gw extraction (qextr) = 33 – 66 % of gw exploitable reserves (qexpl); and – under pressure, when gw extraction (qextr) > 66 % of gw exploitable reserves (qexpl). 2.2. methods of assessing pressure on groundwater quality at the eu level, several technical reports have been prepared for the purpose of assisting and contributing to the process of harmonisation of approaches to and procedures for pressure on water quality and risk assessment, as the report made by the groundwater working group (gw wg) in 2003 (gw wg, 2003). besides the national reports of the eu members, similar concepts were also followed during preparation of the rbmps of large internationally shared basins, such as that of the danube, adopted by the international commission for the protection of the danube river (icpdr) in 2010 (icpdr, 2010) or the sava river, adopted by the international sava river basin commission (isrbs) in 2014 (isrbs, 2014). for the purpose of rbmp, the pressures on water quality of each of the receptors delineated groundwater bodies (gwb) should be estimated based on groundwater vulnerability (margat, 1968), hazard and risk assessment according to diffuse and point pollutant sources. in the most recent deca­ des, vulnerability assessment of groundwater and aquifers has become a necessary tool for planning and managing groundwater 3 the category "potentially under pressure" is not recognised in wfd or eu reference application documents (cis). however, we suggest this category in rbmps for a pragmatic reason: to warn the decision makers and local populations that groundwater extraction must be applied with caution and coupled with systematic monitoring of its effects. g eo lo gi a c ro at ic a geologia croatica 73/2110 resources. in combination with hazard and risk maps, vulnerabi­ lity maps point to endangered areas of special significance (springs, quality water reservoirs, national and nature parks, etc.) that need to be proactively protected. one of the objectives is to demonstrate that natural protection varies from one site to the next, and that especially vulnerable places can exist even within the same aquifer system or groundwater body. vulnerability mapping and presentation of results in gis is applicable to all types of rocks/aquifers, but it is especially important for karst terrains, due to their inhomogenous and anisotropic properties. the concepts of the “european approach” to mapping karst groundwater vulnerability are introduced in practice by the project cost 620 (zwahlen, 2004). therefore, the following can be distinguished: 1) methods designed for karst aquifers (e.g. epik method, dörfliger, 1996), and 2) methods applicable to other aquifers, with special emphasis on karst (e.g. pi method ­ goldscheider, 2005). in addition to these two, there are several other methods that are used, among the most frequent being drastic (aller et al., 1987), and cop (vías et al., 2002). the weak point of these and many other methods that have been developed for the purpose of vulnerability assessment is the fact that empirical parameters are chosen without physical basis and established common classification (neukum & hötzl, 2005). experience has shown that a specific methodology could be developed for any terrain and related aquifer systems. as such, the authors of this article developed the original soda method, which was applied for the first time in the rbmp for the sava river basin in bosnia & herzegovina (stevanović & marinović, 2015). those rbmps were adopted during 2016 at the national level under the agency for the sava river basin (asrb) for the federation of bosnia and herzegovina, the public institution waters of srpska (piws) for the republic of srpska and the government of brčko district (gbd) for the brčko district. the acronym soda comprises the following parameters: – parameter s – (slope) inclination of terrain, – parameter o – (overlying strata) soil, surficial strata and cover of underlying aquifer, – parameter d – (depth) to the groundwater table, and – parameter a – (aquifer) type of locally present aquifer. for each of the parameters, there are weighting factors that consider local­specific circumstances and characteristics. the factors range from 1 to 10, in such a way that smaller weighting factors correspond with the appropriate conditions, favourable for water protection, while larger numbers correspondingly raise the aquifer vulnerability. for instance, in case of parameter s, flat terrains which enable longer water retention and possible greater infiltration should be marked by higher factors than highly inclined terrains. or in the case of a, highly permeable aquifers require a factor with a higher weighting than those that are moderately or less permeable. the index for each pixel on the map can be obtained by combining these factors for the chosen vulnerability algorithm. after the creation of all four base layers (maps) in gis, the final aquifer vulnerability (v) map can be completed based on different algorithms. one of them, which logically emphasises the primary importance of parameters a (aquifer) and o (overlying strata), is: v = (s x 1) + (o x 3) + (d x 2) + (a x 4) (3) equation (3) shows that each pixel within slope, overlying strata, depth and aquifer layer was multiplied by numbers 1, 3, 2 and 4, respectively. the vulnerability map was then created by summarizing those new values for all four layers which are in the range from 10 – 100. the selection of vulnerability classes depends on obtained values, and the ranking of indexes should be equitably balanced to avoid extremes; in other words, neither low nor highly vulnerable classes should be dominant. one of the possible categorisations is shown in table 1. the main anthropogenic influences on the chemical status of gwbs include two main groups: diffuse pollution sources, and point sources of pollution. the hazard maps (the results of possible pollution from present diffuse and point pollutants, (daly et al., 2002) and risk maps (combination of hazards and intrinsic (natural) vulnerability of the terrain) of groundwater should be created separately because of the impossibility of performing common mathematical calculations of vector and raster data in the gis environment. the easiest way to create a groundwater hazard map based on diffuse pollution sources is to transform the corine land use map created jointly by the european environment agency and european topic centre terrestrial environment (eea & etcte) in 2018. in accordance with the legend that represents a constituent part of the corine 2018 map, each pixel on the map is assigned a value that indicates a type of land cover. since land use can be one of the most important indicators of the sensitivity of water quality to pollution, a load coefficient of 0 to 1 should be appointed to each pixel on the map depending on the potential pollution hazard. these assigned values are empirical, and the largest values are commonly present in zones of mining, landfills, waste dump sites, heavy industry or irrigated areas with intensive crop production, as these can have a high impact on groundwater quality deterioration as diffuse pollution sources. for transformation of corine’s values into load coefficients (hazard indices) some of the procedures, e.g. the one from the eu project cc-ware (čenčur curk, 2014) could be applied. in this way, a groundwater hazard map after diffuse pollutants would have several hazard classes based on the ranking of the hazard indices (table 1). the groundwater hazard map based on point pollutants has to be created separately from that for diffuse pollutants and is commonly presented as a map with circles showing the intensity of threats at their exact locations. the main input for the hazard map based on point pollutants is the current population equivalent (pe) load which reflects the equivalence between the polluting potential of an industry and a particular population, which produces the same polluting load (sperling & chernicha ro, 2005). each point pollutant is expressed as population equivalent load (pe load) and, depending on the pe load and according to the ratio of the minimum and maximum calculated loads, a circle of a precisely determined radius is attributed to each point pollutant. although the main purpose of this kind of map is just a visualization of the threats, an actual hazard based on point pollutants can be represented as a ratio of the area covered by circles and the surface of a studied gwb, although such an approach always includes a high level of subjectivity. this is why a risk assessment is much more accurate if we compare the intrinsic vulnerability and hazard from diffuse pollution sources (daly et al. 2002). this concept includes a combination of a groundwater vulnerability map and a groundwater hazard map based on diffuse pollution sources: in other words, the risk of pollution will depend on both the potential diffuse pollutants and the vulnerability of the aquifers and groundg eologia c roatica zoran stevanović & veljko marinović: a methodology for assessing the pressures on transboundary groundwater quantity and quality ... 111 water. for example, the low degree of intrinsic groundwater vulnerability can exaggerate risk due to diffuse pollution in the same gw body. in contrast, if there are no activities in the vulnerable catchment area, the risk can be still low. the risk mapping metho­ dology implies the multiplication of each pixel from the vulnerability map with the corresponding hazard map pixel, resulting in a proportional index of risk (i.e. risk = vulnerability x hazard) (table 1). in general, the first two categories could be considered as “no pressure”, the following two as “potentially under pressure”, and the last two as “under pressure”. depending on the % of the surface which the designated risk categories cover, each of the studied gwb could be proclaimed at risk or not. the status “conditionally under pressure“ could also be applied, just in case that insufficient data regarding land use and local activities and pollutants are collected and evaluated, and that preliminary assessment is thus considered probable and not certain – meaning that it requires confirmation by way of operational gw monitoring. data gaps and inconsistencies have become apparent in many national reports, resulting in uncertainties in the interpretation of the presented data. it is therefore common to establish a level of confidence high – medium – low for the assessment of groundwater status for each studied gwb. 3. results based on the platform described above, the analyses and assessment of pressures on aquifer systems have been encompassed in the dinaric region of se europe (fig. 1). table 1. one of the possible categorisations of the intrinsic aquifer vulnerability, hazard and risk after diffuse pollutants and corresponding pressures (risk) categories. aquifer (gwb) vulnerability classes index gw hazard classes index gw risk classes index pressures – final risk categories impervious rocks 0 10 no hazard 0 – 0.10 no risk < 1 no pressure (not at risk)very low 11 30 very low 0.11 – 0.33 very low 1 – 10 low 31 50 low 0.34 – 0.60 low 11 – 30 potentially under pressure (potentially at risk)moderate 51 70 moderate 0.61 – 0.70 moderate 31 – 49 high 71-90 high 0.71 – 0.80 high 50 – 72 under pressure (at risk) very high 91 -100 very high 0.81 – 1.0 very high 73 – 100 figure 1. the distribution of karst in the former yugoslavia (herak, 1972, modified) with karst transboundary aquifers (tba). g eo lo gi a c ro at ic a geologia croatica 73/2112 the first example shows the outcomes of the project that has been implemented in practically the entire dinaric region with the aim of focusing the attention of the international community on the huge but vulnerable water resources contained in karst aquifers within the dinaric chain. diktas is an acronym of the gef (global environment facility) regional project “protection and sustainable use of the dinaric karst transboundary aquifer system”, which was implemented in the period 2011­2015. at the regional level, the main project objectives were to facilitate equitable and sustainable utilisation and management of the transboundary water resources, and to protect the unique groundwater dependent ecosystems that characterise the dinaric karst region from natural and man­made hazards, including climate change (stevanović et al. 2016). the conducted transboundary dia­ gnostic analysis (tda) was based on substantial regional ana­ lysis and focused on selected and prioritised transboundary groundwater bodies (tgwbs), examining current and potential issues of concern. based on five criteria (importance, representa­ tiveness, data availability, issues of concern, relevance), eight tgwbs were initially selected for detailed analysis. one of them, tgwb una (fig. 2), has a total area of about 1773 km2, of which 78% is karst terrain primarily composed of limestones of mesozoic age. the croatian proportion of the tgwb is 1605 km2 (of which 77.5% is karst), and the b&h proportion is 168 km2 (80% is karst). the groundwater flow directions are exclusively from croatia to b&h, as identified by numerous dye tracing tests which traversed the boundary between the two countries (biondić et al., 2010). the average dynamic reserves of groundwater in the tgwb una are about 34 m3/s. the minimum recorded discharge of springs is assumed to correspond to the minimum ecologically acceptable flow. this value for the springs in croatia is 0.86 m3/s table 2. available and tapped (utilised for public water supply) groundwater reserves in the tba una. average springs discharge / dynamic reserves, qdyn (m3/s) ecological flow – qeco (m3/s) exploitable reserves qexpl.= qdyn – qeco (3) = (1) – (2) actually utilised groundwater (m3/s) water demands (m3/s) ratio water demands. vs. qexpl (%) (5) vs. (3) risk 1 2 3 4 5 6 7 34 5.81 28.19 0.685 1.32 4.7% no figure 2. a hydrogeological map of the una transboundary aquifer shared between croatia and bosnia & herzegovina (after diktas database, modified). g eologia c roatica zoran stevanović & veljko marinović: a methodology for assessing the pressures on transboundary groundwater quantity and quality ... 113 and in b&h it is 4.95 m3/s, for the total of 5.81 m3/s (table 2). the tapped amount of groundwater used for the water supply in b&h is 0.52 m3/s. in croatia, it is about 0.165 m3/s, for the total of 0.685 m3/s. this includes industry and the inhabitants connected to centralised water supply systems. it is estimated that approximately 35­40% of the inhabitants in the area are not served by these systems and instead obtain their drinking water from smaller local (rural) waterworks, individual wells or smaller figure 3. map showing the categories of groundwater quantitative and qualitative risks of gwbs delineated in the sava river basin in the territory of federation of bosnia & herzegovina (fb&h) (according to asrb, 2016). g eo lo gi a c ro at ic a geologia croatica 73/2114 tapped springs. by connecting these consumers to the municipal systems and envisaging some 20% of additional water for cove­ ring the future population and tourism growth and industrialisation, the total water demands for the next 25 years may increase to 1.32 m3/s. the comparison of water demands and exploitable reserves shows that tgwb una is far from being at risk when it comes to water quantity, and that sustainable development of the gwb can continue for many decades. even during drought seasons, water demands are much lower than the minimal discharge of springs as a guaranteed ecological flow (19.1%). nevertheless, detailed interdisciplinary scientific investigations and measures should be carried out in order to obtain harmonious, reliable and sustainable development in a very complex, valuable and vulnerable ecological and social dinaric karst system, taking into account an extreme stress on the dinaric karst water resources (bonacci, 2014). the corresponding methodology for quantitative pressures and risks has been applied in the river basin management plan for the wb of the sava river basin in the territory of the federation of bosnia & herzegovina (fb&h). the criteria for the risk categories and limits are as follows: – no pressure (not at risk), when gw extraction (qextr) < 33 % of gw exploitable reserves; – potentially under pressure (potentially at risk), when gw extraction (qextr) = 33 – 66 % of gw exploitable reserves; and – under pressure (at risk), when gw extraction (qextr) > 66 % of gw exploitable reserves. the analyses of fb&h, as one of the two existing entities in bosnia & herzegovina, is very important because the majority of the delineated gwbs are of transboundary character and are shared with another entity the republic of srpska and neighbouring croatia. out of 17 delineated gwbs, only three are completely internal. out of these 17 gwbs, 11 are not at risk (2/3), three are potentially at risk, while three were found to be at risk (asrb, 2016, fig. 3). the analyses of diffuse and point pollutants in the same river basin have resulted in the assessment that 75% of the gwbs are not at risk, that 20% actually are at risk, and that just 5% are potentially at risk (fig. 3). as a result of the application of the soda method, the classes of moderate to high vulnerability prevail and cover 68,6% of the sava river basin in the territory of fb&h, while very high vulnerability characterises 4,86% of the basin. several “strategic” projects for groundwater resource evaluation have been conducted in serbia between 2008 and 2012. one of them evaluated the actual status and needs for improvement of groundwater monitoring, and serbia became one of the first countries in europe that created an aquifer vulnerability map that covered the entire national territory (milanović et al., 2010). later, creation of an aquifer vulnerability map for the entire country became a requirement for all eu member countries as well as eu candidate countries especially when coping with the water framework directive. this regional map was created in gis, and its details were adjusted to be in accordance with a scale of 1:500.000 (milanović et al., 2010, fig. 4). according to the aquifer vulnerability map, the moderate vulnerafigure 4. an aquifer vulnerability map of serbia and kosovo* (left) (milanović et al., 2010, modified); and the groundwater risk map of serbia and kosovo*(right) (stevanović & marinović, 2016). g eologia c roatica zoran stevanović & veljko marinović: a methodology for assessing the pressures on transboundary groundwater quantity and quality ... 115 bility class has the widest distribution in serbia (46% of the country). based on the vulnerability map and the hazard map (according to diffusing pollutants), a risk map covering the entire territory of serbia and kosovo* was also created (fig. 4). the risk map includes three main categories: 1. the zones with a very high risk of groundwater pollution are distributed around the main urban agglomerations, industrial and agricultural areas, and along river valleys with busy traffic corridors. 2. moderate (43%), and 3. low to moderate (22%) categories have the widest distribution in serbia. concerning transboundary water management, the aquifers under greater risk of pollution are located in the se – timok valley (near bulgaria), the west – lower drina valley (near bosnia & herzegovina) and the danube valley (near croatia). the transboundary gwb prokletije is shared by montenegro and albania (fig. 5). the surface located in montenegro is estimated at 70 km2. this is a highly mountainous terrain where the highest peaks reach 2190 m a.s.l. the total drainage of karst aquifers in montenegro is on average c. 5 m3/s, more than half of which is the discharge of the alipašini springs (q min/max = 2.5 – 7 m3/s, radulović, 2000). this is a typical case of exploitable reserves greatly exceeding the actual water extraction which is less than 1% of the reserves. the gwb would not be at risk even if water demands experienced significant growth. the application of soda showed a relatively high aquifer vulnerability: the class „moderate to high“ covers approximately 60% and „very high“ around 10% of the surface area (fig. 5), but the tgwb is not at risk as there are no industrial polluters on either side of the border. however, diffuse sources of pollution which include agricultural areas, local landfills, the local road network and small villages not connected to a sewage system, should be closely monitored and the environmental situation should be improved to prevent water quality deterioration. 4. discussion the objective of this article is to present a methodology that could facilitate the process of assessing the quantitative and qualitative status of groundwater, especially on a “regional scale”, meaning at the level of a country or a large river basin. a more detailed and advanced methodology is recommended for smaller river basins and catchments. for instance, the danube rbmp (icpdr, 2010) has only evaluated transboundary groundwater bodies larger than 1000 km2, while detailed delineation of groundwater bodies is left to the rbmp of each country that belongs to the basin. the eu wfd has also set forth a logical concept “ from the larger to the smaller river basin”, and thus the plan for larger basins should contain data of a more general nature, while the degree of detail should increase with the transition to smaller river basins. the problem often faced by hydrogeologists preparing rbmps, especially in developing or “transitional” countries, is the lack of data on groundwater distribution and regime. for example, in montenegro – a country abundant in groundwater – only one karst spring and a few piezometers are observed on a permanent basis. in serbia, 375 currently observed piezometers are located in 41 out of the totally delineated 153 gwbs (stevanović & dokmanović, 2015). the rbmp for the danube (icpdr, 2010) indicates the main components of the methodologies that were used to assess the risk of failure to achieve good chemical status. these are: the available monitoring data on water quality, data on existing pressures and possible impacts, data on the overlying strata of the groundwater bodies, and the corresponding vulnerability of the aquifer. it should be noted that risk assessment methods are rather country­specific and range from using combinations of the afore-mentioned data sets to focus on interpreting water quality data. how to fill the gaps in the knowledge of gwbs and aquifer systems and apply the proposed methodology? in many cases it figure 5. the vulnerability map of prokletije transboundary gwb. g eo lo gi a c ro at ic a geologia croatica 73/2116 will be necessary to approximate some of the parameters, or to average the values of some sporadically undertaken field tests. for example, when creating a vulnerability map using the recom­ mended soda method, it is difficult to collect precise data on the “depth” parameter (depth to the groundwater table) at the surface of the studied gwbs. to overcome this gap, one might take into consideration the elevation of drainage points (springs) or erosional bases (rivers) towards which groundwater flows are oriented. in the former case, in well­developed karst, a rough approximation includes interpolated elevations within the interior of the catchments, in a way that is similar to that shown on fig. 6. in the case of an alluvial aquifer located closer to a riverbed as an erosional base, groundwater tables are shallower and can be approximated in a similar way (fig. 6). although the latter is a concept that generalizes the process of determining the depth to the groundwater table in alluvial aquifers in cases when there are no sufficient piezometers or wells, this simplified concept is the only way to approximate the depth to the groundwater table. the problem of data shortage could be recompensed by additional hydrogeological and environmental surveys, at least at designated problematic locations. remote sensing could support mapping of aquifer systems. if discharge data for the largest springs is missing, a series of measurements in high/low periods could provide basic ideas on the presence and regime of groundwater. similarly, hydrochemical in situ prospection and a series of chemical analyses of micro-constituents may enable assessment or confirmation of the water quality and trends. the preparation of rbmps of large basins usually takes between 1.5 – 3 years, which is sufficient time to organise at least annual monitoring at the main water points (springs or boreholes). furthermore, with support of hydrological and/or hydrodynamic modelling, this data could be used in forecasting the effects of climate changes or possible artificial interventions (stevanović, 2015). the existing and most frequently applied concept to assess pressure on groundwater quantity is based on water table observation. in many cases, significant water table depletion is a clear indicator of over­extraction of groundwater and a sign of pressure. however, in highly dynamic aquifers such as those that are karstic, even a large amplitude of water table fluctuation could be the result of temporarily changed natural conditions and might not necessarily be caused by water abstraction. it is therefore much more accurate to assess pressure on gwbs by evaluating water budget elements on a multiannual or annual basis. efficient technologies offered by gis software packages enable the creation of a simple database, quick calculation, and (visually) well presented spatial parametrisation. the three steps of gis mapping have proven to be the most efficient way of asses sing and visualising the groundwater distribution and quality status. although mainly of regional character, obtained data and categorisation of gwb by use of the suggested methodology support the following: 1. foundation for a more detailed analyses and rbmps of smaller basins; 2. organisation of groundwater monitoring; 3. definition of a programme of measures for groundwater protection; 4. sustainable development of aquifer systems and water sources; 5. optimisation of spatial planning and land use; 6. crea­ tion of early warning and information exchange systems as part of transboundary water management. rbmp and its programme of measures (pom) could serve as a starting point for planning more detailed research, which may include modelling of different water use scenarios, forecasting of pollution trends, climate change impacts. although not recommended for concrete projects such as selecting landfill sites, choosing new road paths or finding appropriate locations for industrial objects, the results obtained could also be used as an initial supportive tool. groundwater monitoring should be based on the results of the groundwater assessment within the rbmp and especially created vulnerability / hazard / risk maps, which should indicate prioritised “hot spots”. the organisation of monitoring should include: 1. selection of monitoring sites as part of a permanent network; figure 6. cross-section 1-2 present an example of the assessment of depth (h) to groundwater table (gwl). g eologia c roatica zoran stevanović & veljko marinović: a methodology for assessing the pressures on transboundary groundwater quantity and quality ... 117 2. selection of the type of monitoring – surveillance or operational (after eu wfd) and 3. definition of monitoring frequency. bonacci (2014) states that the complex, valuable and vulnera ble ecological and social dinaric karst system requires technical, social, economic, environmental, and cultural measures in water resources management. the results could support such a proposed interdisciplinary approach and measures, but also be useful for educational purposes and local technical capacity building. wider promotion of rbmps may also help decentralise the water sector and get local capacities more involved, especially those from areas indicated to be under various kinds of threats and risks. visualised results (maps, statistics) and their promotion through media may also help raise public awareness concerning the importance of saving and protecting water and the environment. the examples from bosnia & herzegovina, montenegro and serbia show that the suggested methodology has been applied with success. the examples presented confirm that pressure on groundwater quantity remains low (table 3); however, the risk of contaminating most of the evaluated aquifer systems does exist and preventive systematic protection, along with monitoring, should thus be applied in the dinaric region. some of the methods presented for assessing pressure on gwbs are novel, while most are commonly used, albeit slightly adapted to the specific circumstances dictated by the presence of numerous karst aquifers. consequently, limits i.e. the percentages used to classify gwbs as belonging to one group of risks or another are modified accordingly. 5. conclusions as an invisible but essential resource, groundwater is utilised globally for a potable water supply. assessing its distribution, status and the pressures on water quantity and quality is one of the main tasks of the river basin management plans introduced by eu wfd as an obligation to member states. although it requires work by professional hydrogeologists, the assessment procedures and results obtained should be applicable and also understandable to a wider audience, as well as water managers and practitioners. considering the complexity of groundwater, the methodology for assessing its status can be very demanding and often difficult to implement. reliable and precise information requires systematic hydrogeological and multidisciplinary field surveys, long-term monitoring, many in situ tests, and above all significant funds and teams of professionals to undertake the work. however, for an initial assessment on a regional scale (large basins or at a country level), some simple procedures as suggested here and the use of gis software may be sufficient. successful application of this methodology is confirmed by the following: – the rbmps for the sava river in the territories of two entities of b&h and the brčko district, prepared by eptisa and hydroplan supported by the current authors, have been approved and implemented. – in serbia, there is undergoing expansion of the national groundwater monitoring network which is actually maintained by the hydrometeorological institute of serbia based on the programme prepared by local experts. during 2017 – 2019, operational monitoring covered an additional 50 gwbs, ensuring that more than half of the total of the delineated gwbs in the country are currently under observation and that the percentage would increase even further. the selection of monitoring sites and prioritisation of the gwbs is fully based on the findings of the risk analy­ sis and maps. – similarly, the first group of 30 piezometers for continual monitoring of groundwater have been installed across montenegro at the most critical hot spots identified from an environmental point of view following the results obtained by this methodology in the rbmp. – due to the successful results of the diktas project and the previously created water management platform, the second phase of this transboundary project is under preparation. it will focus mainly on the water management infrastructure and the data exchange mechanism between the respective countries of the dinaric region. finally, creating a foundation for more detailed analyses and preparing the rbmps of smaller basins, organising groundwater monitoring, and raising public awareness of the importance of sustainable water use and protection are just some of the advantages of the proper application of this methodology. acknowledgment the authors would like to express their gratitude to the anonymous reviewers for their careful review and useful comments. references aller, l., bennet, t., lehr, j., petty, r. & hackett, g. (1987): drastic: a standardized system for evaluating ground water pollution potential using hydrogeologic settings.– chicago, illinois, u.s: epa asrb (2016): sava river basin management plan in federation of b&h, sarajevo (availa ble at: www.voda.ba) bedell, r.l., jr. (1995): gis for the geosciences.– sparks, nevada, usa: homestake mining company. biondić, b., biondić, r. & meaški, h. (2010): the conceptual hydrogeological models of the plitvice lakes.– geologia croatica, 63/2, 195–206. doi: 10.4154/ gc.2010.17 table 3. assessment of pressures on groundwater quantity and quality for studied groundwater bodies. groundwater body water demands vs. qexpl (%) pressure on gw quantity vulnerability hazard risk pressure on gw quality tgwb una (b&h/cro) 4.7 no n/a n/a n/a n/a gwbs in sava river basin of b&h 11 gwbs nr 3 gwbs pr 3 gwbs r mostly moderate and moderate to high low to moderate low to moderate 12 gwbs nr 1 gwb pr 4 gwbs r tgwb prokletije (montenegro-albania) 1 not at risk moderate to high low low not at risk serbia 71 gwbs nr 12 gwbs pr 8 gwbs r mostly moderate mostly moderate mostly low to moderate risk 57 gwbs nr 31 gwbs pr 3 gwbs r nr – not at risk; pr – potentially at risk; r – at risk; n/a – not applicable (not discussed in this paper). http://www.voda.ba g eo lo gi a c ro at ic a geologia croatica 73/2118 bonacci, o. (1987): karst hydrology; with special reference to the dinaric karst.– springer­verlag, berlin. bonacci, o. (2014): karst hydrogeology/hydrology of dinaric chain and isles.– environ. earth. sci., 74, 37–55 (2015). doi: 10.1007/s12665­014­3677­8 burke, j.j. & moench, h.m. (2000): groundwater and society: resources, tensions and opportunities [special edition of desa and iset].– new york: un public. st/ esa/265 čenčur curk, b. (2014): cc­ware mitigating vulnerability of water resources under climate change, wp­3, annual report. chang, k.t. (2008): introduction to geographical information systems.– new york, mcgraw hill. custodio, e. (1992): hydrogeological and hydrochemical aspects of aquifer overexploitation. [selected papers of iah], vol. 3, verlag heinz heise, 3–27. cvijić, j. (1893): das karstphänomen. versuch einer morphologischen monographie.– geographischen abhandlung, wien, v(3), 218–329. daly, d., dassargues, a., drew, d., dunne, s., goldscheider, n., neale, s., popescu i. c. & zwahlen, f. (2002): main concepts of the “european approach” to karst­groundwater­vulnerability assessment and mapping.– hydrogeo­ logy journal, 10/2, 340–345. doi:10.1007/s10040­001­0185­1 dörfliger, n. (1996): advances in karst groundwater strategy using artificial tracer tests analysis and multiattribute vulnerability mapping (epik method).– unpubl. phd thesis, university of neuchatel, switzerland, 308 p. ec (2000): directive 2000/60/ec of the european parliament and of the council of 23 october 2000 establishing a framework for community action in the field of water policy.– off. j. eur. communities 2000, brussels. ec (2006): directive 2006/118/ec of the european parliament and of the council of 12 december 2006 on the protection of groundwater against pollution and deterioration.– off. j. eur. communities 2006, brussels. ec (2007): common implementation strategy for the water framework directive (2000/60/ec). guidance document no. 15, guidance on groundwater monitoring, brussels ec (2009) common implementation strategy for the water framework directive (2000/60/ec). guidance document no. 18, guidance on groundwater status and trend assessment, brussels. ec (2015): common implementation strategy for the water framework directive (2000/60/ec). guidance document no. 34, guidance document on the application of water balances for supporting the implementation of the wfd, brussels. eckstein, y. & eckstein, g.e. (2005): transboundary aquifers: conceptual models for development of international law.– ground water, 43/5, 679–690. doi: 10.1111/j.1745­6584.2005.00098.x eea & etcte (2018): corine land cover 2018. retrieved from https://land.copernicus.eu/pan­european/corine­land­cover/clc2018 esri (environmental systems research institute) (2003): spatial data standards and gis interoperability. esri white paper [online]. available at http://www.esri.com/library/whitepapers/pdfs/spatial­data­standards.pdf fao aquastat (2018): website, available at: www.fao.org/nr/aquastat/ ford, d. & williams, p. (2007): karst hydrogeology and geomorphology.– chiche ster: john wiley & sons ltd, the atrium, southern gate, 562 p. doi: 10.1002/9781118684986 gbd (2016): sava river basin management plan in brčko distrikt, draft version, brčko (available at: www.bdcentral.net) goldscheider, n. (2005): karst groundwater vulnerability mapping: application of a new method in the swabian alb, germany.– hydrogeology journal, 13/4, 555–565. doi: 10.1007/s10040­003­0291­3 gw wg (2003): wfd pressures and impacts assessment methodology: guidance on pressures and impacts methodology. paper by the working group on groundwater and working group on characterisation and reporting. guidance document no. gw4. wfd ireland. gwp / inbo (2012): the handbook for integrated water resources management in transboundary basins of rivers, lakes and aquifers. paris (https://www.inbo­news.org/ img/pdf/mgireb­uk­2012­2.pdf) herak, m. (1972): karst of yugoslavia.– in: herak, m. & springfield, v.t. (eds.): karst: important karst regions of the northern hemisphere. amsterdam: elsevier. 25–83. icpdr (2010): danube river basin management plan, vienna austria, www.icpdr.org isrbs (2014): sava river basin management plan, zagreb, croatia, www.savacommisison.org margat, j. (1968): vulnerabilité des nappes d’eau souterraine a la pollution [groundwater vulnerability to contamination ].– orleans: bases de la cartographie (doc.) 68 sgc 198hyd, brgm margat, j. (1992): the overexploitation of aquifers. [selected papers of iah], vol. 3, 29­40, verlag heinz heise. margat, j. & van der gun, j. (2013): groundwater around the world: a geographic synopsis. london: crc press. doi: 10.1201/b13977 meinzer, o.e. (1920): quantitative methods of estimating groundwater supplies.– bull. geological society of america, 31, 329–338. mijatović, b. (1984): hydrogeology of the dinaric karst. vol. 4. hannover: international association of hydrogeologists, heise. milanović, p. (2005): water potential in south­eastern dinarides.– in: stevanović, z. & milanović, p. (eds.): water resources and environmental problems in karst cvijić 2005, belgrade, faculty of mining and geology, 249–257. milanović, s., stevanović, z., đurić, d., petrović, t. & milovanović, m. (2010): regionalni pristup izradi karte ugroženosti podzemnih voda srbije – nova metoda “izdan” [regional approach in creating groundwater vulnerability map of serbia – а new „izdan“ method – in serbian].– in: proceedings of the xv serbian geological congress belgrade, 585–590. neukum, c. & hötzl, h. (2005): standardisation of vulnerability map.– in: stevanović, z. & milanović, p. (eds.): water resources and environmental problems in karst cvijić 2005, belgrade, faculty of mining and geology, 11–19. piws, (2016): sava river basin management plan in the republic of srpska, draft version, bijeljina (available at: www.voders.org) puri, s. & aureli, a. (2005): transboundary aquifers: a global program to asses, evalu ate, and develop policy.– ground water, 43/5, 661–668. doi: 10.1111/j.1745 ­ 6584.2005.00100.x puri, s. & struckmeier, w. (2010): aquifer resources in a transboundary context: a hidden resource? enabling the practitioner to ‘see it and bank it’ for good use.– in: earle, a. jägerskog, a. & öjendal, j. (eds.): transboundary water mana­ gement: principles and practice, 73–90. london: earthscan. radulović, m. (2000): hidrogeologija karsta crne gore [karst hydrogeology of montenegro].– podgorica: geological survey of montenegro. radulović, m.m. (2012): višeparametarska analiza prihranjivanja karstne izdani na primerima iz sliva skadarskog jezera [multi-parameter analysis of groundwater recharge in karstic aquifer – case examples from the skadar lake basin].– unpubl. phd thesis, university of belgrade, belgrade, serbia. sperling, m.v. & chernicharo, c. (2005): biological wastewater treatment in warm climate regions, vol. 1; iwa publishing, london, uk, isbn 978­1­84339­ 002­2. stevanović, z. (2015): characterization and engineering of karst aquifers.– switzerland: springer international publishing. stevanović, z. (2018): karst aquifers in the arid world of africa and middle east: sustainability or humanity?– in: younos, t., scheriber, m., kosič ficco, k. (eds.): karst water environment: advances in research, management and policy. the handbook of environmental chemistry, vol. 68, springer, cham, 1– 43. stevanović, z. (2019): karst waters in potable water supply: a global scale overview.– environmental earth science. springer, 78, 662. doi: 10.1007/s12665­019­8670­9 stevanović, z. & dokmanović, p. (2015): creation of new extended groundwater monitoring network of serbia.– unpublished manuscript, department of hydrogeology, faculty of mining and geology, university of belgrade, serbia. stevanović, z. & marinović, v. (2015): river basin management plan for sava river in federation of b & h, volume 4 groundwater. technical documentation of the ipa project “strengthening capacity in water sector of bosnia & herzegovina”.– sarajevo, bosnia & herzegovina. eptisa & hydroplan. stevanović, z., marinović, v., merdan, s., skopljak, f. & jolović, b. (2015): koncept izrade hidrogeoloških podloga za planove upravljanja rečnim slivovima [conception of creating basic documents in hydrogeology for river basin management plans].– in: proceedings of 1st geological congress of bosnia & herzegovina tuzla, bosnia & herzegovina: geological society of bosnia and herzegovina, tuzla, 150–151. stevanović, z. & marinović, v. (2016): the role and importance of hydrogeo­ logy in the creation of river basin management plans at a regional scale.– in: proceedings of the iwa specialist groundwater conference, belgrade: institute for the development of water resources “jaroslav cerni”, 180–186. stevanović, z., kukurić, n., pekaš, ž., jolović, b., pambuku, a., & radojević, d. (2016): dinaric karst aquifer – one of the world’s largest transboundary systems and an ideal location for applying innovative and integrated water management.– in: stevanović, z., krešić, n. & kukurić, n. (eds.): karst without boundaries. london: crc press/balkema, eh leiden; taylor & francis group, 3–25. unga and international law commission (2008): the law of transboundary aquifers. vías, j.m., andreo, b., perles, m.j., carrasco, f., vadillo, i. & jiménez, p. (2002): preliminary proposal for contamination vulnerability mapping in carbona­ te aquifers.– karst and environment, 75–83. wise gis (2016): guidance on the reporting of spatial data to wise. (http://cdr.eionet. europa.eu/help/wfd/wfd_521_2016/gisguidance/wise_gisguidance.pdf) wmo, commission for hydrology. (http://www.wmo.int/pages/prog/hwrp/chy/) worboys, m. & duckham, m. (2004): gis: a computing perspective. boca raton: crc press. world water council (2010): fact sheet: transboundary water security. marseille: 6th world water forum kick­off. zwahlen, f. (2004): vulnerability and risk mapping for the protection of carbonate (karst) aquifers.– luxembourg: cost action 620, office for official publications of the european communities. https://land.copernicus.eu/pan-european/corine-land-cover/clc2018 https://land.copernicus.eu/pan-european/corine-land-cover/clc2018 http://www.bdcentral.net https://www.inbo-news.org/img/pdf/mgireb-uk-2012-2.pdf https://www.inbo-news.org/img/pdf/mgireb-uk-2012-2.pdf http://www.icpdr.org http://www.savacommisison.org http://www.savacommisison.org http://www.voders.org http://cdr.eionet.europa.eu/help/wfd/wfd_521_2016/gisguidance/wise_gisguidance.pdf http://cdr.eionet.europa.eu/help/wfd/wfd_521_2016/gisguidance/wise_gisguidance.pdf http://www.wmo.int/pages/prog/hwrp/chy/ geologia croatica 45 5361 6 fig. 2 pl. l tab. zagreb 1992 udc 552.32:552.12 (497.13) scientific paper spilite from kamešnica, mt. kalnik, nw croatia maja vrkljan1 keywords: spilites, mt. kalnik, hydrothennal alteration, cretaceous volcanism the results of microscopic and chemical investigation of spilites from the upper coarse of the stream kamešnica and from iu tributary kalnički potok on mt.kalnik (north-western croatia) have been described. spilites arc a result of posr.rnagmatic hydrolhermal alteration of the basic effusive rocks. they are of upper cretaceous age. l. introduction the present study deals with a number of spilite outcrops found in the northern part of the kalnik range. these outcrops are located about 1.5 to 2 km north of kalnička greda in the upper coarse of the stream kamešnica and its right tributary kalnički potok. sampling locations of the ten selected and investigated samples are presented in fig. l. 7>ill'' [ o..__..;o-=s=~---1. 5. km \ \ vratno križevci fig. l . the position of kalnik and sampling locations. slika l. položaj kalnika i mjesta uzimanja uzoraka 2. previous investigations occurrence of exposed sections of diabase rock in the stream of kamešnica was first mentioned by wolf (1861-62). microscopic analyses of diabase occurrences from kamešnica were presented by kišpatić (1913). apart from the weathered diabase, in the stream he found oliv ine diabase and olivine gabbro pebbles. the position of weathcrcd dia base outcrops was confmned by pou ak (1914, 1942). he observed that the exposed diabase extruded on the contact between oligocene and cretaceous sediments. well exposed upper cretaceous ključne riječi: spili ti, kalnik, hidrotennalna izmjena, kredni vulkanizam opisani su rezultati mikroskopskog i kemijskog istraživanja spilita iz gornjeg toka kamešnice i iz kalničkog potoka na kalniku u sjeverozapadnoj hrvatskoj. spilili su nastali postmagmatskim hidrotermalnim izmjenama bazičnih efuzivnih stijena i g om jok redne su starosti. clastic sediments with diabase and spili te in kamešnica are adduced by šimunić & šimunić (1979). the area of kamešnica was mapped as a zone of basic effusive rocks comprising of diabase, spilitised diabase and spilite (šimunić et al., 1982). the results of detailed micro-scopic and chemical analyses of eruptive rocks from this area were presented by vrkljan (1989). 3. summary of geology and field relationship the sediments which host the spilites in the upper coarse of kamešnica are described (šimunić & šimunić, 1979, šimunić, 1983) as those ofhetero­ geneous petrographic composition, comprising of sandstone, shale, mari, chert, limestone, silificated limestone and tuff. the sequence hosts disparately arranged allochthonous blocks and fragments of dolomite, limestone and sandstone of triassic, jurrasic and cretaceous age. the sequence contains eruptive rocks, and the limestone fossil data indicate an albianupper cretaceous age of this complex. the spilite outcrops are mainly small, their size is up to a few meters. a site of a small quarry is the largest exposed outcrop of spili te, about 80 m wide and located upstream from the mouth of the drenovčak on the right bank of kamešnica (pl. i, fig. 1). the eruptives are intensely weathered, with altered and crumbly surfaces. the dense vegetation and the humus layer cover the edges· of the outcrops. 4. resu l ts and discussion the region of the upper coarse of kamešnica was sam pled with 30 samples out of which l o were analysed in detail both microscopically and chemically. the rocks are of green and gray nuance with uneven impregnations of a red-violet pigment, and have uneven, 'institute of mineralogy, petrology and economic geology, university of zagreb, pierottijeva 6. 41000 zagreb, croatia 54 step-like or weak shelly fracture. they are clearly aphanitic. irregular veinlets ranging from very thin to about 6 mm thick are common. 4.1. individual minerals the analysed rocks have quite uniform mineral composition with distinct differences in abundance, size, number and disposition of the constituents. all samples contain al bite, clinopyroxene, chlorite and the minerals of the zoisite-epidote group. a majority of the samples contain calcite, magneti te, hematite and titanite. minecals such as quartz, ilmenite, sericite (illite?), zeolite, prehnite, pyrite, pumpellyite and clay minerals occured only in a few samples. albite. only in several porphyritic rocks is albite present as phenocrysts and in the groundmass. sample 7 contains numerous albi te phenocrysts, mainly in clusters (pl. i, fig. 2), while some samples contain only rare phenocryst clusters. the phenocrysts are usually subhedral. the largest of these have dimensions of about 0.8 x 0.5 mm, and are commonly simple twins or polysynthetic twins. some grains show symmetrical extinction angles < 5°. the grains contain inclusions of chlorite, calcite, minerals of the zoisite-epidote group, and sporadically clay minerals. the main constituent of the porphyritic rock groundmass is also albite. the largest sections are 0.5 mm long and 0.06 mm wide. the polysynthetic twins are usually of the albite law. they are arranged like the plagioclases in the diabase (pl. l, fig. 3). lath-shaped and acicular sections aligned bundly and fan-like occur in some samples (pl. i, fig. 4). a subparallel arrangement in some samples indicates a trachytic texture. groundmass albites contain frequently inclusions of ch lori te, minerals of the zoisite-epidote group, calcite or still very small un determined colour less to greenish inclusion s. rarely, they contain inclusions of sericite (illite?) and prehnite. the inclusions sometimes cover the whole surface of the section, while elsewhere margins or central parts, and sometimes occur along cleavage fissures. the size of al bite crystals in rocks of aphyric texture varies in each individual sample. the dimensions of the largest sections are 1.45 x 0.97 mm. by means of theodolitic microscope measurements chemical compositions of three grains from one sample were determined. it varies from 5 to lo% an. the measured angle 2v is positive. al bites of aphyric rocks are very similar to those of porphyritic texture, but the former contain also inclusions of pumpellyite and titani te with leucoxene. all the sections of al bites at the contact with canada balsam have at least one refractive index less then that of the balsam. clinopyroxene. only two samples contain preserved phenocrysts of clinopyroxene mainly as rare four-sided sections of a light-skinpink colour. some samples sporadically contain only their small relict fragments, geologia croatica 45 while other samples retained only euhedral and subhedral con tours of either individual or clustered phenocrysts. various in size, the largest are 0.7 x 0.5 mm. the largest isometric sections are about 0.5 mm in diameter. their most common replacement products are ch lori te, zoisite­ epidote group of minerals, calcite and sporadically hematite. · groundmass pyroxenes in samples with porphyritic texture occur as fine isometric sections with diameters up to 0.06 mm or as short prismatic sections up to 0.56 x 0 .05 mm. in some samples relict fragments of clinopyroxenes are observed, and in sample l only their contours containing secondary minerals are preserved. a few samples contain skeletal clinopyroxenes with shapes that give the appearance of a spinifex texture. they have pink-brown colour with very weak pleochroism. the pyroxenes are cracked, and often have irre gular extinction, and in sample 6 they show "hourglass structure". ~eplacement products are: epidote-zoisite, chlorite, calc i te and hematite. some rims are opacitized. apart from the already mentioned alteration products, clinopyroxenes in aphyric rock samples contaip titanite, partly altered to leucoxene. hematitized magnetite and comby, poorly hematitized ilmenite were also observed. optical properties of clinopyroxenes in one sample were determined by means of theodolitic microscope. the measured extinction angle z:c which ranges from 45 to 52° and +2v from 50 to 53° and other observed properties imply that they are titanoaugites. chlorite. all samples contain chlorite, as an alteration product. greenish aggregates are arranged along the margins and in cleavage fissures of phenocrysts and groundmass minerals, or occupy, together with other alteration products, the con tours of primary clinopyroxene crystals. chlorite also occupies the interstices of al bite and pyroxene grains as yellowish green to green leptochlorite aggre gates with weak pleochroism. some samples contain kidney-shaped forms of handed chlorite which resemble colloidal products. the intensity of hematitization of such forms varies considerably (pl. i, fig. 5). chlorite sometimes replaces all of the rock constituents (pl. i, fig. 6). zoisite-epidote group of minerals. determination of epidote as a replacement product of clinopyroxene or as a mineral that occupies vesicles was possible only in some cases. most samples contain numerous fine­ grained aggregates of colour less to greenish minerals with high refraction indexes and low .to bright interference colours. these probably belong to zoisite-epidote group of minerals. calcite is present in almost all investigated rock samples. it is one of the alteration products of original minerals, and in places almost completely fills the contours of original clinopyroxenes. sporadically, just like chlorite, it replaces all of the rock constituents. magneti te. in most samples magnetite occurs either on rims and in fissures of altered and opacitized clinopyroxenes or as subhedral and anhedral grains of vrkljan : spilite from kamešnica ... various size unevenly dispersed over the whole sample section. it is abundant in sample 3. hematite. magnetite is commonly partly altered to hematite, and in most rock samples these minerals occur together. in some samples hematite is also an alteration product of comby ilmenite. sporadically uneven impregnations of hematite are present in spaces between albites and clinopyroxenes. titani te. a majority of samples contain titanite as an alteration product of clinopyroxene. sometimes it is partly altered to leucoxene. quartz. few samples contain quartz either in the groundmass of porphyritic rocks, or in interstices of albites and clinopyroxenes in aphyric rocks. ilmenite. com by and skeletal crystal shapes and only rarely irregular sections of ilmenite occur in a few samples mainly in contours ofprevious clinopyroxenes together with chlorite, magnetite and titanite. usually it is partly altered to leucoxene. sericite (illite?). some samples contain alteration products of original plagioclase which resemble sericite and illite. zeolite. a small quantity of zeolite occurs in one sample in the space between essential minerals. by means of optical investigation it was not possible to determine the type of zeolite and separation due to small quantities was also impracticable. pyrite is observed in two samples as rare, fine, wealdy hematitized grains. in sample 7 the larger impregnations are present on the margins of a thin fissure. prehnite, pumpellyite and clay minerals occur rare in company with other alteration products as inclusions in the albites. the numerous arnygdules and vein le ts are of various size, shape, number and composition. chlorite is their usual constituent. some contain only ch lori te while others in addition contain calcite, quartz, epidote and zeolite. in some arnygdules chlorite occurs on their margins (pl. ii, fig. 1), and in others in their central parts. the walls of the amygdules filled with epidote are surrounded by a narrower or wider zone consisting of an opacite aggregate (pl. ii, fig. 2). the similar zone about 0.5 mm wide surrounds some vesicles filled with calcite of irre gular extinction (pl. ii, fig. 3). this zone contains finely dispersed leucoxene, iron oxides and very fine vesicles about 1.3-0.4 mm in diameter filled with calcite, chlorite and ep i dote. quartz and zeolite fill scarce vesicles and veinlets. hematite occurs rarely in veinlets as impregnations together with colloidal chlorite. titanite occurs in veinlets also rarely. some samples contain, toge ther with the above mentioned minerals, numerous micro to cryptocrystalline colourless to green i sh arborescent aggregatcs and fan­ like and dendritic aggregates, whose determination was not possible (pl. il, fig. 4). 4.2. strucfural and 1extural varieties in the investigated area of a relatively small surface ss and short distance between outcrops a number of structural and textural varieties are observed. a smaller number of samples display an homogeneous structure. the amygdaloide structure prevails. the rocks ofhomogeneous structure are porphyritic and show a relict intergranular-intersertalto hyalophitic groundmass texture. the rocks of arnygdaloidal structure occur both as porphyritic and aphyric varieties. porphyritic rocks have various groundmass texture: relict intergranular-intersertalto hyalophitic, coarse arborescent with poorly expressed properties of a pilotaxitic, and a fme arborescent aphyric rocks have relict intergranular to intersertal texture with more or less expressed features of a hyalophitic texture. one sample has a relict hyalopilitic texture with barely noticeable characteristics of a relict intersertaltexture. in most porphyritic samples the texture is glomeroporphyritic. 4.3. chemical composition and classification bulk rock chemical composition of 10 spili te samples and the calculated cipw norms are presented in t a b l e l. the chemical composition is characterized by high abundances of na and al and low abundances or even absence of k. the high content of na in relation to prirnary basalt is related to secondary albite enrichment of all samples due to spilitization. high al is the result of its association with numerous secondary chlorites. according to merriman et al. (1986) k-feldspar o' 2 6 3 • 8 6 • .9 'l l! lal (ll b) 2 f' fig. 2. q'(f)-anor diagram after s1reckeisen & le maitre (1979). slika2. q'(f)-anordijagram (slreckeisen & lemaitre, 1979). s6 geologia croatica 4s l 2 3 4 5 6 7 8 9 lo si01 40.81 41.18 44.02 42.72 49.12 47.01 44.62 45.65 44.87 44.13 ti0 1 2.50 1.73 1.91 2.10 1.59 1.70 1.41 1.94 1.94 0.89 al10 3 17.82 18.42 15.66 18.92 18.21 15.59 16.43 14.28 18.09 15.05 fe 2 0 3 2.65 2.99 4.60 2.89 2.61 3.47 3.25 2.88 4.61 2.84 feo 5.79 4.63 2.51 5.31 6.32 7.23 7.94 4.57 3.52 5.53 mn o 0.18 0.16 0.10 0.18 0.12 0.12 0.16 0.08 0.16 0.13 mg o 12.70 9.76 4.29 9.99 5.33 5.94 6.57 5.06 9.96 8.77 cao 4.61 8.45 13.87 7.04 6.41 9.51 10.78 12.31 4.50 11.46 nap 4.58 4.56 4.33 4.07 6.17 5.25 4.30 4.40 6.20 4.38 ~o 0.00 0.00 0.82 0.36 0.00 0.00 0.00 0.22 0.24 0.00 p los 0.44 0.40 0.37 0.42 0.14 0.37 0.11 0.39 0.25 0.03 ~o· 4.81 4.50 4.53 4.73 3.80 2.89 3.21 4.06 4.40 3.71 ~o1.37 0.79 0.55 0.87 0.58 0.52 0.36 0.59 0.84 1.24 c02 2.54 3.11 2.87 0.79 0.00 0.18 0.95 4.16 1.14 2.19 :e 100.80 100.68 100.43 100.39 100.40 99.78 100.09 100.59 100.72 100.35 e 3.06 or 5.28 2.22 1.45 1.50 a b 29.87 19.39 16.87 25.68 43.65 31.75 21.17 25.62 35.79 16.14 an 22.24 32.25 22.52 34.36 • 22.05 22.94 22.85 19.68 26.66 20.18 ne 6.53 12.13 12.30 5.91 5.79 7.81 9.14 8.07 10.71 12.78 di 8.46 25 .06 0.13 7.61 21.98 23.29 34.87 0.11 30.27 wo 7.25 o l 28.03 18.59 22.04 12.70 9.35 11.74 0.33 18.45 11.58 mt 4.18 4.71 3.06 4.45 3.94 5.24 4.94 4.55 6.59 4.43 hm 2.86 0.35 il 5.17 3.56 3.94 4.24 3.13 3.36 2.81 4.12 3.92 1.81 a p 1.01 1.01 0.94 1.08 0.37 0.91 0.27 1.01 0.60 0.07 l norm. p lag. 43 52 57 60 34 38 56 44 38 59 l (%an) table l chemical analyses (in weight %) and cipw norms of spilites tablica l kemijski sastav (%)i cipw normativni sastav spilita (%) generally does not occur in metabasic rocks of the prehnite-pumpellyite facies. since the mineral composition of all tfc samples was not possible to determine completely, due to micro and cryptocristalline constituents, figurative points of analysed samples were plotted on a q'(f)-anor diagram (streckeisen & le maitre, 1979). the diagram contains norm data calculated by the niggli-barth system (barth, 1962). the plotted figurative points fall in fields of basanite and also alkali basalt and andesite respectively (fi g. 2). andesite and basalt are distinguished by the recommended (streckeisen, 1978) ratio of si0 2 wt% and the normative colour index from normative composition according to the niggli-barth system. according to this ratio the rock samples are basalts and leucobasalts (fig. 3). the analysed samples plotted on the t as diagram, which is also a recommended classification scheme for effusive rocks of incompletely determined modal composition (le bas et al., 1986), fall into the fields of basic rocks (fi g. 4 ). e. i. l basalt : i(j l • l 7 ' l ~ ----------t--------------------+--• • 1 . l eli ' jo lo u. • l ~ ~ l • l leukobasalt l6 48 so l l l fig. 3. c.i. si0 1 diagram after streckeisen (1978). slika 3. c.i. si0 1 dijagram (streckeisen, 1978.). on the basis of mineral constituents and their relationships, structure, texture, chemical composition and the presented diagrams, all the rocks can be classified as spilite. 4.4. genesis the present mineral composition and chemistry of the investigated rocks are a result of intensive vrkljan : spilite from kamešnica ... na.p•k,o (%) ll l6 ls so fig. 4. tas diagram after le bas et al. (1968). slika 4. t as dijagram (le bas et al., 1968). s2 si01 (%) postmagmatic hydrothermal alteration, notably spilitization. since alteration has affected all rocks the character of the initial magma cannot be determined. on the si01-(nap-kp) diagram (kuno, 1968) and the ne-ol-di-hy-q diagram (yoder & tilley, 1962) figurative points of the analysed samples plot in nn,o·k,o('io) • • ' • • & alkali • ' 2 basalts •• • lo • 7 • • tholentlc basal ts ~-··====~,----':-:=:--:-:--=--:-:-u w ~ n ~ ~ ~ ~ u s•o,!'io) fig. 5. si02 (na20 + k,o) diagram after kuno (1968). slika 5. si02 (na,o + k,o) dijagram (kuno, 1968). the fields of alkali basalt (fi g. 5) and alkali oliv ine basalt (fig. 6) respectively. this is due to the high na resulting from spilitization, intensive chloritization and removal of excess si. the prevailing amygdaloidal structure implies an expansion of gasses and vapour from lava extrusions on or near the surface. also rapid crystallization is imp lied by dominating relict microdiabase textures, sometimes with arborescent shapes, such as skeletal pyroxene of spinifex texture. this features suggest quick solidification of magma due to rapid cooling (wimmenauer, 1985). variation of textures on a relatively short distance infers to various positions of cooling inside the magmatic bodies. distinct pillow structures (pl. ii, fig. 5) imply submarine lava extrusions. during such extrusions sea water can penetrate into the contraction cracks and cause spilitization (wedepohl, 1988). however, some 51 ot fig. 6. ne-ol-di-hy-q diagram after yoder & tilley (1962). slika 6. ne-ol-di-hy-q dijagram (yoder & tilley, 1962). outcrops exhibit no pillow structures, no contraction cracks, suggesting an assumption that unconsolidated sediments, into which basalt intruded, contain seawater, a source of na for spilitization. iuvenile water could have also caused spilitization by imbuing the rocks and reacting with primary basalt minerals and engendering their alteration . beside spilitization, other hydrothermal alterations were observed, suggesting a variable composition of circulating solutions and migrability of individual elements. the alteration occurred in conditions of very low to low-grade metamorphism. depletion of k in submarine basalts is interpreted by wedepohl (1988) as an alteration of basalt in an open system at temperatures exceeding 150°. direct contact of eruptive with surrounding sedim en ts was not observed in the investigated area. sediments that embody the investigated spilites are upper cretaceous in age (šimunić & šimunić, 1979, šimunić, 1983). spilites from the area of the upper coarse of kamešnica are analogous in mineral composition, structure, texture and even chemical composition to spilites of other parts of kalnik (vrkljan, 1988, 1989, vrkljan & vragović, 1991), for which an upper cretaceous age is presumed. thus an extention of this age to the investigated spilites is possible. s. conclusion the spilites from the upper coarse of kamešnica, together with sediments of heterogeneous petrographic composition, compose a heterogeneous complex of upper cretaceous age. all the samples contain albite (5 10% an), clinopyroxene (titanoaugite), chlorite and minerals of the zoisite-epidote group. most samples include also calcite, magneti te, hematite and titani te. other minerals, present according to quantity, are quartz, ilmenite, sericite (illite?), zeolite, prehnite, pyrite, pumpellyite and clay 58 minerals. phenocrysts of albi te and clinopyroxene em body numerous inclusions. albite and clinopyroxenes are also groundmass minerals and main constituents of aphyric rocks. structural and textural varieties are relatively numerous. amygdaloidal structure prevails together with relict diabase and microdiabase texture. spilites of the investigated area are a result of intensive postmagmatic hydrothermal alteration, particularly spilitization. the lavas had extruded either into a submarine environment or into unconsolidated sediments containing seawater. there are some indications that juvenile water has also contributed to alteration of primary rocks. the alteration occurred in conditions of very low and low-grade metamorphism. it is most likely that the circulating fluids were of diverse composition and that individual elements were of various migrability. 6. references barth, t.f.w. (1962): theoretical petrology. john wiley and sons, 416 p., new york. kišpatić, m. (1913): kristalinsko kamenje kalnika. rad jazu, 200, 161-174, zagreb. kuno, h. (1968): differentiation of basalt magmas. -in: hess, h.h. & poldervaart, a. (eds.): basalts, vol. 2. intersci. publ., 623-688, new york. le bas, m.j., le maitre, r.w., streckeisen, a. & zanettin, b. (1986): a chemical classification of volcanic rocks based on the total alkalisilica diagrarn.jour. petrol., 27,3, 745-750. merriman, rj ., bevins, r.e. & ball, t.k. (1986): petrological and geochemical variations within the tal y fan intrusion: a study of element mobility during low-grade metamorphism with implications for pctrotectonic modelling.jour. petrol., 27, 6, 1409-1436. pou ak, j. (1914): iz geologije kalničke gore. vijesti geol. povj. za kralj. hrvatsku i slavoniju, 3-4, 93-100, zagreb. pou ak, j. (1942): prilog poznavanju geologije kalničke gore. v jestnik hrv. drž. g eo l. zavoda i hrv. drž. geol. muz., l, 1-43, zagreb. geologia croatica 45 streckeisen, a. (1978): classification and nomenclature of volcanic rocks, lamprophyres, carbonatites and melititic rocks.n. jb. miner. abh., 134, l, 1-14, stuttgart. streckeisen, a. & le maitre, r.w. (1979): a chemical approximation to the modal qapf classification of the igneous rocks. n. jb. miner. abh., 136, 2, 169-206, stuttgart. simunić, al. & simunić, an. (1979): litofacijelno r~članjivanje mezozojskih naslaga kalničkog gorja. zbornik radova iv god. znanstv. skupa sekcije za primjenu geol. geofiz. i geokem. znanstv. savjeta za naftu jazu, (a), 7, 125-137,zagreb. simunić, an. (1983): pregled geološke građe sjevero­ zapadne hrvatske."varaždinski zbornik" 11811981, 41-52, varaždin. simunić, an., pikija, m. & hećimović, i. (1982): osnovna geološka karta sfrj, 1:100.000, list varaždin, l 33-69. inst. geol. istraž. zagreb (1971-1978), sav. geol. zavod, beograd. vrkuan, m. (1988): eruptivne stijene iz pake (kalnik, sjeverozapadna hrvatska). geol. vjesnik, 41 , 133144, zagreb. vrkljan, m. (1989): eruptivne stijene kalnika.di­ sertacija, 94 p., zagreb. vrkljan, m. & vragović," m. (1991): spiliti iz gornjeg toka glogovnice i rakovog potoka (kalnik, sjeverozapadna hrvatska). geol. vjesnik, 44, 181193, zagreb . . wedepohl, k.h. (1988): spilitization in the ocean crust and seawater balances. fortschr. miner.,66, 2, 129-146, stuttgart. wimmenauer,w.(1985):petrographie qer mag.mati­ schen und metamorphen gesteine. ferdinand enke verlag, 382 p., stuttgart. wolf, h. (1861-62): die geologische verhaltni~se des kalnikgebirges und der u mgebung von w arasdin­ teplitz in croatien. verh. geol. reichsanst, xi, 229-230, wien. yoder, h.s. & tilley, c.e. (1962): origin of basalt magmas: an experimental study of natural and synthetic rock systems. jour. petrol., 3, 342-532. plate tabla l l. outcrop of spilite, kamešnica. izdanak spilita, kamešnica. 2. albite phenocrysts in clusters, n (sample 7). nakupine fenokristala albita, n (uzorak 7). 3. relict diabase texture, n (sample 3). reliktna dijab~zna struktura, n (uzorak 3). 4. bundly and fan-like albites, n. svežnjasti i lepezasti agregati albita, n. 5. chlorite of colloidal ~hape _impregnated with hematite, n. klorit koloidalnog oblika impregniran hematitom, n. 6. chlorite replaces all of the rock constituents, n+ (sample 3). klorit potiskuje sve sa~tojke. stijene, n+ (uzorak 3). vrkljan :spil ile from kamejnica ... platetabla i 59 2 3 0.2 mm 5 60 geologia croatica 45 spiliti iz gornjeg toka kamešnice, kalnik, sz hrvatska m. vrkljan s piliti iz gornjeg toka kamešnice na sjevernom dijelu kalničkog gorja bili su do sada relativno slabo istraženi. na sl. l. naznačena su mjesta uzimanja 10 detaljnije istraženih uzoraka. eruptivne stijene se nalaze u sedimentnim naslagama heterogenog petrografskog sastava starosti alb-gornja kreda. najveći izdanak je lokacija nekadašnjeg manjeg kamenoloma (tabla l, sl. 1). svi uzorci sadrže albit, klinopiroksen, kloriti minerale iz grupe co i si ta i ep i dota. v ećina uzoraka sadrži kalcit, magnetit, hematit i titanit. ostali minerali, po zastupljenosti, su kvarc, ilmenit, sericit (ilit?), zeolit, prehnit, pirit, pumpeliit i minerali glina. fenokristali su zastupljeni albitom (tabla i, sl. 2) i klinopiroksenom, a sadrže brojne uklopke. albit i klinopiroksen nalaze se i kao minerali osnove, a glavni su sastojci i afirnih stijena. teodolitnomikroskopski utvrđen je kemizam al bita (5 l 0% an), a klinopiroksen je determiniran kao slabotitanski augit. raspored albi ta u osnovi porfirnih stijena, kao i u afirnim stijenama ponegdje je karakterističan za dijabaze (tabla i, sl. 3), a u nekim uzorcima albiti tvore svežnjaste i lepezaste agregate (tabla i, sl. 4 ). albiti i klinopirokseni sadrže brojne uklopke sekundarnih minerala. klorit je zastupljen obilno i u različitim oblicima, od bubrežastih forma koje podsjećaju na koloidalne tvorevine (tabla i, sl. 5) do listićastih agregata koji potiskuju sve sastojke stijena (tabla i, sl. 6). mnogobrojne mandule i žilice različite su veličine, oblika, zastupljenosti i sastava, a oko nekih se zapaža uži ili širi rub koji sadrži opacitski agregat (tabla il, sl. 1-3). osim navedenih minerala u nekim se uzorcima zapažaju obilni mikro do kriptokristalasti bezbojni i zelenkasti arborescentni sastojci, te lepezaste i dentritične tvorevine, koje je teško prepoznati (tabla ii, sl. 4). teksturna-strukturni varijeteti su relativno brojni. prevladava amigdaloidna tekstura, te reliktne dijabazne i mikrodijabazne strukture. kemijski sastav istraženih uzoraka spilita i njihov normativni sastav po cipw sustavu navedeni su u tablici l. figurativne točke unijete su u q' (f')anor, si0 1 c.i. i tas dijagrame koji su prikazani na sl. 2-4. karakter ishodne magme ne može se utvrditi, a na dijagramima si0 1 -(nazd+kzd) i ne-ol-di-hy-q figurativne točke nalaze se u poljima alkalijskih bazalta (sl. 5) odnosno alkalijskih olivinskih bazalta (sl. 6). spilili istraženog područja rezultat su intenzivnih postmagmatskih hidrotermalnih izmjena, osobito spilitizacije. lave su se izlijevale submarinski, na što ukazuju mjestimice lijepo izražene pillow-strukture (tabla il, sl. 5), ili u nekonsolidirane sedim.ente koji su sadržavali morsku vodu. na izmjenu primarnih stijena utjecale su i juvenilne vode. stijene su izmijenjene u uvjetima od vrlo niskog do niskog stupnja metamorfoze, a može se pretpostaviti različiti sastav cirkulirajućih otopina i različita migrabilnost pojedinog elementa. nije zapažen neposredni kontakt spilita i okolnih sedimenata. na osnovi utvrđene gornjokredne starosti sedimenata u kojima se nalaze istraženi sp iliti, te sličnosti istraženih stijena sa spilitima ostalih područja kalnika, oni, uz sedimente heterogeno g petrografskog sastava, sačinjavaju heterogeni kompleks gornjokredne starosti. manuscript received march, 31. 1992. revised manuscript accepted june, 29. 1992. plate -tabla ii l. chlorite on the margin of an amygdule, n (sample 2). klorit na rubu mandule, n (uzorak 2). 2. an amygdule filled with epidote and surrounded by an opacite aggregate, n. mandula ispunjena epidotom i okružena opacitskim agregatom, n. 3. an opacite aggregate near the boundary of a vesicle filled with calcite, n. opacitski agregat uz rub mandule ispunjene kalcitom, n. 4. microlites of albi te and arborescent constituents of a rock, n (sample 5). mikroliti albita i arborescentni sastojci stijene, n (uzorak 5). 5. spilite of pillow structure, kamešnica. kuglasta lučenje spilita, kamešnica. vrkljan : spilite from kame~nica ... platetabla ii 61 2 3 0.2 mm .. .. ~ · . . • l. 10-kovacic.indd 121 � ab stra ct the petrographic composition and transport direction of medium and coarse-grained clastic material of dilj gora mt. which is located in the south pannonian basin, shows that this area experienced several changes in provenance of the detritus through the neogene. detritus for the oldest lower miocene (ravan unit) was generally transported from the south and most probably derived from clastic and carbonate sediments and metamorphic rocks of the internal dinarides. detritus of the lower–middle miocene (tuk unit) probably originated by weathering of acid magmatic and metamorphic rocks, with signifi cant input of materials from local sources, primarily from the internal dinarides and from požeška gora and dilj gora mts. during the entire middle miocene (zdenci, dubovik and glogovica units), and through the older part of the late miocene (croatica and pavlovci unit), the deposition of siliciclastic gravel and sandy detritus was less signifi cant. only the middle miocene deposits (kasonja unit) contain clastic detritus derived from granitoids, metamorphic and sedimentary rocks of the hinterland. the source area of this detritus was most probably in the slavonian mts. (papuk, psunj, požeška gora mt.) or the mountains of northern bosnia (motajica mt.). at late upper miocene times (andraševec and nova gradiška units), detritus was derived from different metamorphic and older sedimentary rocks. the structural and mineralogical maturity of these sediments, and their transport directions, indicates an alpine-carpathian provenance of the material. most of the detritus of the pliocene sediments (cernik unit) also belong to an alpine-carpathian provenance, however a small part of it is of local origin and came from uplifted and mainly sedimentary rocks. various textural characteristics and diverse modal compositions were determined, and the provenance of neogene clastic material of dilj gora mt. can be attributed to differing source rock compositions and locations of source areas. however, they are also the product of different controls on sedimentation, including different rates of subsidence and extension of the pannonian basin (pb) interrupted by compressional events, basin water-level fl uctuations connected with global sea-level changes and infi lling of pb by delta progradation. keywords: pannonian basin, dilj gora mt., neogene sediments, detritus composition, clastic material source composition and provenance of neogene sedimentary rocks of dilj gora mt. (south pannonian basin, croatia) � marijan kovačić1, marija horvat2, mato pikija3 and damir slovenec2 1department of geology, faculty of science, university of zagreb, horvatovac 95, 10000 zagreb, croatia; (mkovacic@geol.pmf.hr) 2department of geology, croatian geological survey, sachsova 2, 10000 zagreb, croatia; (mhorvat@hgi-cgs.hr; dslovenec@hgi-cgs.hr) 3gajnice 3, 10090 zagreb, croatia doi: 104154/gc.2011.10 geologia croatica 64/2 121–132 6 figs. 1 tab. zagreb 2011 geologia croaticageologia croatica crn ko, 1973; šparica et al., 1980a,b; 1987a,b, špa ri ca et al., 1988). the origin of neogene sediments of dilj gora mt. is related to the development of the pb and its surrounding uplifted areas. namely, the pb is a sedimentary area surrounded by the alps, carpathians and dinarides, and is composed of several smaller depressions separated by shallow 1. introduction dilj gora mt. is one of the slavonian mountains located in eastern croatia (fig. 1), belonging to the south pannonian basin (pb). it consists of neogene and quaternary sediments with rare occurrences of magmatic rocks (šparica & geologia croatica 64/2geologia croatica 122 lying basement rocks (fig. 1). since its formation in the ear ly miocene, a huge amount of clastic material has been transported with varying intensity into and within the pb (mattick et al., 1988; juhász, 1991; juhász & magyar, 1992; vakarcs et al., 1994; magyar et al., 1999; thamó-boszó & juhász, 2002; saftić et al., 2003; kova čić et al., 2004; thamóné boszó et al., 2006; tha mó boszó & kovács, 2007). deposition of this material in the pb formed a sequence of sediments reaching several thousand meters in thickness in some depressions (saftić et al., 2003). six boreholes from the nearby area drilled into quaternary and neogene sediments for about 2000 m depth. four of them reached the crystalline basement: tekić-i (northwest from dilj gora mt.) ended in gneiss phyllonite (najdenovski, 1988), visoka greda-1 in biotite-amphibole granite and visoka greda-2 in amphibole schist (amphibolite?) west of dilj gora mt. (pikija, 2004) and djakovačka breznica-1 (šparica, 1985) in mica schist to the northeast. another two boreholes nova kapela-1 and garčin-1 ended in lower miocene conglomerates (pikija, 2004). source areas for this huge amount of material in the pb were primarily related to the surrounding mountain chains of the dinarides, alps, and carpathians, which were uplifted before and during the formation of the pb. however, part of the material was also derived from locally uplifted mountains within the basin (kovačić & grizelj, 2006). dilj gora mt. is located in the southern pb near the northern margin of the dinarides but the dinaridic provenance has been determined only for the youngest quaternary sediments (mutić, 1993). previous investigations determined an origin of the material in the distant north alpine-carpathian sources for pleistocene loess sediments (mutić, 1990) and upper miocene sediments (kovačić et al., 2004; kovačić & grizelj, 2006). the origin of clastic material of lower and middle miocene deposits has not yet been studi ed in detail. the main goal of this study is to determine the composition of clastic sedimentary rocks and reconstruct the origin of clastic material supplying the sediments of dilj gora mt. during the neogene by integrating sedimentological and petrographic data. furthermore, data is used to reconstruct changes in transport directions or intensity of sedimentation in the study area during the miocene. 2. geological setting the pb is a back-arc type of basin (royden, 1988; kováč et al., 1998). its formation began in the early miocene due to the subduction and continental collision of the eurofigure 1: map of the neogene pannonian basin, showing depocentres of the sub-basins, with location of dilj gora mt. thickness of the neogene–quaternary sedimentary rocks in the pannonian basin, compiled by horváth in royden & horváth (1988). kovačić et al.: composition and provenance of neogene sedimentary rocks of dilj gora mt. (south pannonian basin, croatia) geologia croatica 123 pean plate under the apulian plate. the fi rst phase of basin development (until the middle badenian), was characterised by tectonic thinning of the crust and isostatic subsidence (syn -rift), while the second phase (from the middle badenian to the quaternary) was marked by cessation of rifting and subsidence caused by cooling of the lithosphere (postrift). the pb is surrounded by the alps, carpathians and dinarides, and palaeogeographically belongs to the area and bioprovince of central paratethys. during the miocene, sea level oscillations strongly controlled sedimentation because a connection of central paratethys with the mediterranean and indo-pacifi c ocean was established and closed several times (steininger et al., 1988, rögl, 1996). marine trans gressions did not fl ood the entire basin. therefore, the basement was disconformably covered by deposits ranging in age from early to late miocene, formed in marine, brackish and fresh-water environments, while some parts of basin were characterised by temporary emersions. the fi nal isolation of central paratethys began some 10.5 ma ago (steininger et al., 1988, rögl, 1996). the nature of the evolution of central paratethys and occurrences of endemic fau nas has necessitated the establishment of local miocene stages (fig. 2a). recent investigations of neogene sediments for the 1:50000 geological map of croatia revealed eleven informal lithostratigraphic units of dilj gora mt. the basic characteristics of these units and their vertical and lateral relationships are shown in a compiled geological column in figure 2b. these units constitute two transgressive − regressive cycles. the fi rst cycle consists of the ravan, tuk, zdenci, dubovik, figure 2a: chronostratigraphic correlation of the mediterranean and central paratethys (after rögl, 1996). figure 2b: compiled geological column of the neogene succession of dilj gora mt. after pikija et al. (2005) and kovačić et al. (2005). legend: 1 – limestone; 2 – clay; 3 – marl; 4 – silt; 5 – sand; 6 – gravel, conglomerates, sandstone; 7 – volcanic fragments. geologia croatica 64/2geologia croatica 124 kasonja and glogovica units which include ?lower–middle miocene sedimentary rocks (pikija et al., 2005), while the second cycle includes the upper miocene sediments of the croatica, pavlovci, andraševec, nova gradiška units as well as the cernik unit, of pliocene age (kovačić et al., 2005). these cycles generally correspond to the fi rst and second sedimentary megacycle described by saftić et al. (2003) in the southern pb. 3. materials and methods seventeen geological columns were investigated (fig. 3) in the fi eld: staro završje-i (stz-i), vučje jame-i (vjm-i), vu čje jame-ii (vjm-ii), pljuskara-i (plj-i), pljuskara-ii (plj-ii), križ-i (krž-i), završje-i (zav-i), završje-ii (zav-ii), tro međa-i (tro-i), kasonja-i (kas-i), bečic-i (beč-i), krajačići-i (kra-i), stari slatinik-i (sts-i), stari slatinik-ii (sts-ii), glogovica-i (glg-i), zdenci-i (zde-i) and zdenci-ii (zde-ii). at some localities, where it was possible, imbrications, cross bed d ing and cross lamination were measured in order to reconstruct sediment palaeotransport directions in the depositional basin. samples for petrographic analysis of clastic sedimentary rocks were collected in order to cover the entire study area, as well as, the entire time span of the neogene deposits. the composition of gravel, conglomerate and sandstones was determined by analyzing 50 thin sections using a polarizing microscope. compositional analysis of the unconsolidated sand-silt sediments was performed in the 0.09−0.16 mm calcite-free fraction. heavy and light mineral fractions (hmf and lmf, respectively), were separated by bromoform liquid (chbr3; δ=2.84 gcm–3). qualitative and quantitative analy sis of hmf and lmf for 32 samples were performed by identifying 300–400 grains per sample using the ribbon counting method (mange & maurer, 1992). 4. results 4.1. ravan unit siliciclastic sediments of the ravan unit are mostly compos ed of poorly sorted sandy silts, sands and gravels deposited in an alluvial-lacustrine environment (fig. 2b). they are the oldest deposits on the dilj gora mt. with a badenian age according to šparica et al. (1980a,b; 1987a,b) and a karpatian age according to pikija et al. (2005). sands, studied at the staro završje (stz-i) and vučje jame (vjm-i, ii) localities (fig. 3) are characterized by their mineralogical immaturity. forty fi ve percent or more, of their composition consists of rock fragments and feldspars (tab. 1). among the rock fragments, particles of unstable rocks such as quartz-sericite schist, quartz-chlorite schist, slate and phyl lite are most abundant. in addition, particles of quartzite, quartz schist and sandstone are ubiquitous. among the feldspars, the kaolinised alkali feldspars prevail, while acid plagioclase with polysynthetic lamellae is very rare. there is some difference in the composition of the hmf among the localities. sands at the stz-i locality contain more opaque minerals and chlorite than transparent heavy minerals (thm). at the vjm-i locality, they are also rich in opaque minerals, figure 3: geological sketch map of dilj gora mt. (simplifi ed from the basic geological map of croatia 1:300000; croatian geological survey, 2009) with locations of the studied sections. legend: 1 – magmatic rocks; 2 – badenian; 3 – sarmatian + pannonian; 4 – pontian; 5 – pliocene; 6 – pleistocene; 7 – holocene; 8 – normal boundary; 9 – transgressive boundary; 10 – fault; 11 – thrust. kovačić et al.: composition and provenance of neogene sedimentary rocks of dilj gora mt. (south pannonian basin, croatia) geologia croatica 125 table 1: modal composition of heavy and light mineral fractions of neogene sands from the dilj gora mt. abbreviations: op – opaque min., ch – chlorite, b – biotite, do – dolomite, thm – translucent heavy minerals, tu – tourmaline, zr – zircon, rt –routile, ap – apatite, am – amphibole, py – pyroxene, ep – epidote, g – garnet, ky – kyanite, st – staurolite, ti – titanite, csp – chromespinel, oth – other translucent heavy minerals, q – quartz, f – feldspar, l – lithic fragments, ms – muscovite, + – minerals with occurrence <1%. and* – andraševec unit, m3-karpatian, m4-badenian, m5-sarmatian, m7 2upper pontian, pl-pliocene sample unit age heavy minerals (%) translucent heavy minerals (thm) (%) light minerals (%) op ch b do thm tu zr rt ap am py ep g ky st ti csp oth q f l ms stz-i 1/1 ra va n m3 65 22 + 13 32 3 1 3 5 27 19 5 3 2 33 13 54 4/1 m3 73 4 2 21 13 10 11 10 34 20 1 1 37 14 49 8/1 m3 61 2 37 10 7 1 6 44 22 3 5 2 40 15 45 vjm-i 3 m3 90 + 10 9 14 8 17 26 24 + + 1 55 18 27 4 m3 87 + 13 10 11 5 16 27 28 1 2 51 19 30 vjm-ii 1/1 m3 23 + + 76 9 + 3 3 38 + 19 13 + 2 6 5 46 28 26 2/1 m3 33 + 66 4 3 1 1 42 + 25 16 2 2 3 49 20 31 7/2 m3 34 1 1 64 11 1 2 19 + 27 31 1 3 3 2 52 23 25 plj-ii 1/2 tu k m3 22 10 7 61 15 7 3 2 17 46 + 2 7 30 13 56 1 2/2 m3 38 16 46 16 7 5 2 11 53 2 4 26 13 58 3 3/3 m3 38 62 24 2 3 4 23 34 3 + 3 1 2 45 21 33 1 kas-i 1/1 ka so nj a m5 36 64 28 2 3 2 10 30 19 3 3 49 41 9 1 7/1 m5 46 54 39 5 + 5 20 11 13 6 52 41 7 15/1 m5 31 69 20 3 7 24 24 11 5 6 49 44 6 1 19/1 m5 56 1 43 20 2 4 2 26 18 11 13 4 57 38 5 beč-i 14/1 m5 28 1 1 70 33 5 22 16 16 3 5 32 53 15 17/2 m5 21 79 21 + 3 32 21 8 8 6 24 69 7 24/1 m5 24 1 75 25 1 3 32 16 11 7 5 43 43 13 1 kra-i 3/2 and* m7 2 5 13 38 38 4 3 4 + 16 + 17 37 6 5 + 6 49 11 10 30 kra-i 6/1 n ov a g ra di šk a m7 2 13 2 85 6 1 3 3 + 60 3 8 11 + 4 50 10 36 4 zav-i 1/1 m7 2 18 32 50 1 + 3 13 28 33 4 11 6 37 12 15 36 4/2 m7 2 11 4 + 85 4 1 2 + 12 20 44 3 10 1 3 50 17 29 4 4/2a m7 2 6 4 4 86 5 + + 2 24 22 22 7 13 + 4 54 18 20 8 5/2 m7 2 10 90 2 + 3 24 21 27 5 12 2 3 48 14 24 14 zav-ii 4/1 m7 2 10 2 5 83 2 1 1 19 24 36 5 9 + 2 67 17 14 2 7/1 m7 2 12 88 2 3 21 24 26 7 14 1 2 60 11 24 5 sts-i 1/1 ce rn ik pl 39 + + 28 32 12 3 19 1 24 18 10 9 4 55 4 41 5/1 pl 44 6 50 14 7 5 7 28 13 4 13 1 8 48 6 44 2 5/2 pl 37 3 60 10 3 4 + 9 1 26 25 7 9 5 58 5 37 sts-ii 1/1 pl 28 + 71 8 2 5 5 17 45 2 12 + 3 53 12 35 2/1 pl 53 47 3 2 2 10 59 12 3 7 2 18 10 72 5/2 pl 18 52 30 9 2 + 5 + 19 40 8 14 2 62 5 33 opposed to the vjm-ii sands, which are rich in thm. in the thm association, epidote, tourmaline, garnet and amphibole are most common. glaucophane is regularly present among the amphiboles. gravels, studied at staro završje (stz-i) and vučje jame (vjm-i) (fig. 3), have a polymictic composition with pebbles averaging 10 cm in size with blocks up to a maximum of 40 cm diameter. sandstone, siltstone, and limestone pebbles (figs. 4a,b) are most common. sandstone types are arkosic arenite, subarkose, sublitharenite and in the case where the intergranular carbonate content increases they belong to the greywackes. some of the sandstones can be described as me ta sandstones. siltstones also carry a signifi cant amount of caco3 and are classifi ed as calcitic siltstones. limestones are mainly represented by micritic facies, but with sandy and recrystallised limestone types, too. their cretaceous age has been proven by fuček (in pikija, 2004). polymictic clast-supported and matrix-supported breccias are rare, but fragments of anchimetamorphic rocks composed of slightly metamorphosed carbonate and marl laminae, and low grade me ta morphic rocks in the range of slate and phyllite, are com mon (fig. 4c). marble and amphibole schists are signifi cant, while granite and rhyolite pebbles are present in small amounts (fig. 4d). the direction of imbricated platy pebbles in column stz-i, measured in two horizons (figs. 5a, b, see page 128) clearly indicates transport of material from the south-southeast. measurements in section vjm-i (fig. 5c) show higher data scattering, but suggest that the material came from the south-southwest. geologia croatica 64/2geologia croatica 126 4.2. tuk unit siliciclastic sediments of the tuk unit are poorly sorted. they are deposited during the karpatian and the lower badenian in a marine environment (fig. 2b). in this unit, clayeysandy silts dominate, while sands, sandstones and gravels appear as lenses. sands studied at pljuskara (plj-ii, fig. 3) are composed of acid volcanic rock particles. besides them, particles of quartzite, chert, slate and phyllite are present. quartz grains are fresh with uniform extinction. some of the feldspar grains are kaolinised, but others are fresh. the composition of the hmf is similar to that of the ravan unit sands, apart from the presence here of fresh biotite (tab. 1). gravels at pljuskara (plj-i; fig. 3), are composed exclusively of pebbles of acid volcanic rocks; alkali feldspar rhyolites, and rhyolitic tuffs up to 3 cm in diameter. figure 4: photomicrographs of diff erent kinds of pebbles and fragments of coarse clastic sediments of dilj gora mt. (a-d) staro završje-i locality (ravan unit); (e) križ-i locality (dubovik unit) and (f) kasonja-i locality (kasonja unit). (a) limestone sample stz-i 1/3f (b) sandstone sample stz-i 1/3a (c) slate/ phyllite sample stz-i 9/1b (d) granite sample stz-i 9/1c (e) acid volcanic glass (perlite) sample krž-i 2/1 (f) garnet-muscovite gneiss sample kas-i 8/2c. kovačić et al.: composition and provenance of neogene sedimentary rocks of dilj gora mt. (south pannonian basin, croatia) geologia croatica 127 4.3. the zdenci, dubovik and glogovica units the basic feature of these units is the predominance of carbonate sediments in relation to siliciclastics. sediments of the zdenci and the lower part of the dubovik unit were deposited during the badenian in a marine environment, while sediments of the upper part of the dubovik unit and sediments of the glogovica unit were deposited during the sarmatian in a reduced marine environment (fig. 2b). in the zden ci and glogovica units (zde-i, glg-i; fig. 3), which are composed mainly of bioclastic limestone, the siliciclastic com ponent is almost completely absent. belak at al. (1991) described the appearance of badenian volcaniclastic sediments of rhyolitic composition at the zdenci locality. in the dubovik unit (tro-i, krž-i; fig. 3) silty marls, calcsiltstones, and calcarenites, apart from the resedimented fossiliferous carbonate material, contain very small amounts of siliciclastic detritus. this siliciclastic material is essentially composed of fresh quartz and feldspar grains. in addition, altered feldspars (alkali feldspar and plagioclase) and rock fragments including quartzite, quartz-sericite schist, chert, acid intrusive rocks, slates and phyllite are also present. furthermore, at the krž-i section, blocks and fragments of acid volcanic rocks: rhyolite, trachyrhyolite, perlite, and devitrifi cated volcanic glass were observed (fig. 4e). 4.4. kasonja unit clastic sediments of the kasonja unit (kas-i, beč-i; fig. 3) were deposited during the sarmatian in a reduced marine environment (fig. 2b). they are composed of siliciclastic and carbonate material. sandy, silty sediments prevail over gravels that only occur sporadically. sands and sandstones are poorly to very poorly sorted, composed of very poorly rounded siliciclastic and carbonate material. among the siliciclastic material fresh quartz and alkali feldspar grains are most abundant, while alterated feldspars, rock fragments (acid volcanic, chert and quartzite) and muscovite fl akes are rare. in the hmf, thm are more abundant than opaque minerals. tourmaline, epidote and garnet are the most abundant transparent phases, while staurolite and titanite are signifi cant (tab. 1). carbonate particles are represented by redeposited fossiliferous material. the gravel (kas-i; fig. 3) is composed of several types of rock fragments. the most common are represented by granite, garnet-muscovite gneiss (fig. 4f), quartzite and quartz sandstone pebbles. 4.5. croatica and pavlovci units the sediments of the croatica unit were deposited during the early pannonian in a littoral brackish lake environment, while sediments of the pavlovci unit were deposited during the late pannonian and early pontian in a brackish lake basin (fig. 2b) (zde-ii; fig. 3). they are built up of limestone and marl containing rare siliciclastic material with grains no larger than silt size. only within the croatica limestones centimetre thick layers of biocalcarenite composed of redeposited middle miocene fossil debris occur. 4.6. andraševec and nova gradiška units clastic material of the late pontian andraševec and nova gradiška units (kra-i, zav-i, zav-ii; figs. 2b and 3) is most ly composed of well sorted sand and silt deposited in prodelta and delta front environments. the main characteristic of the material is the predominance of siliciclastic detritus. quartz is most frequent, followed by rock fragments, feldspar and muscovite (tab. 1). quartz grains are subrounded, while well rounded and poorly rounded grains are very rare. among the rock fragments, quartzite is signifi cant, while chert fragments are notable as well. quartz-chlorite schist, quartz-sericite schist, slate, phyllite and quartz-feldspar bearing rock fragments are rare. feldspars are altered. the most abundant feldspar is orthoclase, while microcline and plagioclase with polysynthetic lamella occur very rarely. thm are dominant in the hmf. garnet and epidote are the most common. amphibole, staurolite, tourmaline, rutile and kyanite are also signifi cant (tab. 1). rutile and tourmaline are well rounded. in these units the amphibole is hornblende (kovačić, 2004). 4.7. cernik unit the clastic material of the cernik unit (sts-i, sts-ii; fig. 3) was deposited during the pliocene in a lacustrine-fl uvial environment (fig. 2b). it is mostly composed of sandy and silty material with a clay component and small gravel lenses. the sorting of the material varies from poor to very good. its modal composition is similar to the composition of the andraševec and nova gradiška units (tab. 1). however, there are some differences. sands of the cernik unit sporadically contain dolomite, and in most cases higher amounts of opaque minerals (predominantly limonite) tourmaline and rock fragments, and less feldspar than those of the andraševec and nova gradiška units. 5. discussion the poorly sorted sediments with gravel pebbles and blocks up to 40 cm in size in the ravan unit, indicate short transport distances of the clastic material. the dominance of unstable rock fragments in the sandy material also implies short transport distances. measurement of imbrication in gravels suggest a general palaeotransport direction for clastic material from the south (fig. 5, fig. 6a,b). the dominance of sandstones, siltstones, micritic and sparitic limestones among the pebbles and sand composition with lithoclasts of sandstones, partly abraded quartz grains and altered feldspars, point to the conclusion that the older sedimentary rocks had the most important role as a source for the clastic material. furthermore, pebbles of anchimetamorphic rocks, marble and amphibole schist, as well as lithoclasts of slate-phyllite, quartzsericite schist, quartz-chlorite schists, quartzite and epidote, garnet and amphibole in sands, show that part of the detritic material originated from weathering of different metamorphic rocks. the dominance of glaucophane in the sandy fraction is very interesting and suggests blue schists as the source rock for part of the material. granitic and rhyolitic pebbles as well as tourmaline, zircon and rutile also indicate an acid geologia croatica 64/2geologia croatica 128 unit) to marine (tuk unit) is an indicator that subsidence of the basin and an increase in accommodation space was faster than the rate of sediment supply. similarly, the reduction of grain size of detritus in the tuk unit in relation to the ravan unit probably was the result of the removal of source areas to the south. it was a consequence of normal faulting occurring along the active southern margin of the pb during that time (jamičić, 1995; pavelić & kovačić, 1999). fossil carbonate debris, which is dominant in the zdenci, dubovik and glogovica units, indicates the leading role of different marine organisms in the production of clastic material. the unaltered character of siliciclastic detritus from the insoluble residue of calcsiltites of the dubovik unit indicates short transport distances, while the mineral composition and rock fragments suggests its origin mainly from acid igneous rocks, and subordinately from metamorphic rocks. the absence of middle and coarse siliciclastic detritus within clastic detritus of these units indicates that during the middle miocene, most of the dilj gora mt. as opposed to other slavonian mts. including psunj, papuk and krndija (pavelić et al., 1998) was out of range of siliciclastic detritus input. at that time dilj gora mt. area belonged to the southern part of central paratethys. in the shallower parts of the sea during the badenian, fossil carbonate detritus was produced (zdenci unit). part of this detritus was resediment ed into deeper basinal areas (dubovik unit). the remainder, after falling sea level due to partial isolation of the basin in the early sarmatian (steininger et al., 1988, rögl, 1996), was eroded and resedimented in the glogovica unit. the origin of acid volcanic detritus of the dubovik unit may be linked to pre-badenian (pikija et al., 2005), and possible badenian (belak et. al., 1991) volcanism in dilj gora mt. area. the presence of gravel and siliciclastic material in the sands of the kasonja unit, beside fossil carbonate debris points to the fact that the western part of dilj gora mt. during the sarmatian, was strongly infl uenced by clastic sedimentation material delivery. textural immaturity of the sandy fraction as well as the signifi cant presence of fresh alkali feldspars, suggests short transport distances. the composition of the material indicates different rock types as sources. pebbles of granite, quartz grains with uniform extinction, particles of acid effusive rocks, alkali feldspars, tourmaline and titanite originated from acid magmatic rocks. garnet-muscovite gneiss, quartzite pebbles and muscovite, garnet, epidote and staurolite originated from metamorphic rocks, while quartz sandstone pebbles and chert particles originated from the same type of sedimentary rock. according to the results it can be presumed that the clastic material of the kasonja unit is of local origin, but it is not possible to determine the exact location of the source area. this detritus may have come from the south, from the mountains of northern bosnia, but could also have arrived from the nearby slavonian mts. (požeška gora mt., papuk or psunj mts.) (fig. 6a), which are also composed of the aforementioned rocks (jamičić & brkić, 1987; jamičić et al., 1987; korolija & jamičić, 1989; šparica et al., 1980a,b, 1987a,b). figure 5: rose diagrams of clast imbrication show palaeotransport of clastic materials in the ravan unit from the south – south-east at stz-i section (a, b) and from south – south-west at vjm-i column (c). magmatic source for the studied clastic deposits of the ravan unit. these results suggest the conclusion that the source area for the clastic material of the ravan unit was composed of various lithologies, mostly older sediments and metamorphic rocks, and was situated relatively close by, most probably south of dilj gora mt. (fig. 6a). pavelić & kovačić (1999) have reported on material transport from the south for the oldest miocene sediments of nearby požeška gora mt. south of the dilj gora and požeška gora mts. lie the mountains of northern bosnia. intensive erosion of these uplifted mountains could provide clastic material which was then transported short distances to the north. motajica, a mountain located 10 km south/southwest of dilj gora mt. in northern bosnia, is a possible source. namely, all rock types found among the gravels and sandy detrital material of the ravan unit can be found at present on motajica mt. at the surface (varićak, 1966; šparica et al., 1980a,b; mutić & dmitrović, 1991). the detritus of the tuk unit is similar to that of the ravan unit. however, the predominance of acid effusive rock fragments and fresh biotite in the sandy fraction, suggest that acid magmatic rocks had the leading role in material production. those rocks are also present at the surface of mt. motajica (varićak, 1966; šparica et al., 1980a,b) but also at the surface of požeška gora mt. and dilj gora mt. this indicates the conclusion that part of the detritus of the tuk unit could be local in origin like that of the overlying units (fig. 2b). the composition, transport directions and depositional environments of clastic detritus of the ravan and tuk units could be related to tectonic events in the southern part of the pb during the early miocene. prior to and during the older miocene, the internal dinarides were uplifted south of dilj gora mt. (pamić et al., 2002). simultaneously, along the southern margin of the pb, in the early syn-rift phase of its development, wnw-sse elongated depressions were form ed (pavelić, 2001; marton et al., 2002). intensive weathering and erosion of the uplifted blocks, primarily of the internal dinarides in the area of northern bosnia, and partly blocks within the pb, produced large amounts of clastic detritus which was deposited in these depressions. changes in the depositional environment from terrestrial-lake (ravan kovačić et al.: composition and provenance of neogene sedimentary rocks of dilj gora mt. (south pannonian basin, croatia) geologia croatica 129 the absence of siliciclastic material in the croatica and pavlovci units shows that during the early late miocene, the area of dilj gora mt. was not under the signifi cant infl uence of clastic material. the only evidence of clastic material input is centimetre thick biocalcarenite layers in the croatica unit composed of resedimented middle miocene fossil debris. poor sorting and low roundness of the detritus suggests short transport distances, most probably from small local uplifts within the southern part of the pannonian basin. these blocks are uplifted due to inversion of the basin and falling sea level at the end of the sarmatian (csontos, 1995; horváth, 1995). coarse and poorly sorted contemporaneous sediments from northern bosnia, south of dilj gora mt. (stevanović & eremija, 1977; šparica et al., 1980a,b), as well as thick sequences of clastic deposits in fresh-water basins within the dinarides (pavelić, 2002), show that during the late miocene, the dinarides produced huge amounts of clastic detritus which was deposited near the mountain chain or within the internal depression. alternatively, material carried by prograding clastic systems from the alps and carpathians were deposited northern of the studied area (mag yar et al., 1999; kovačić et al., 2004; kovačić & grizelj, 2006). the well sorted and relatively well rounded particles in the andraševec and nova gradiška units indicate its textural maturity, while the dominance of quartz and highly resistant rock particles prove their mineral maturity. such a mature material could have been produced by lengthy transport or by multiple recycling. measurements of cross stratifi cation and cross lamination (pavelić, 2001; kovačić & grizelj, 2006) in sandy sediments imply transport of material from the north. the roundness of the quartz, tourmaline and rutile grains, together with the altered feldspars and the dominance of resistant thm in the hmf suggest that part of the detritus came from older sediments. the particles of low metamorphic rocks, quartz with undulatory extinction, heavy minerals like chlorite, epidote, garnet, kyanite and staurolite indicate different metamorphic rocks as additional sources of material. the presence of hornblende suggests that part of the material could have magmatic origin. such composition of late miocene detritus was determined in the wider area of the south-western part of the pb (šimunić & šimunić, 1987; kovačić & grizelj, 2006). the modal composition, textural maturity and transport directions of the detritus of the upper miocene andraševec and nova gradiška units indicates that this material was derived from the weathering of different, predominantly sedimentary and metamorphic rocks, from sources situated relatively far to the north of dilj gora mt. (fig. 6b). these results are consistent with investigations of provenance of clastic detritus deposited during the late miocene in the south-western (kovačić & grizelj, 2006; kovačić et al., 2009) and central parts of the pb (thamóné boszó et al., 2006). their results suggested the conclusion that this material originated from the alps and the carpathians, and was delivered into the pb by prograding clastic systems. the progradation of clastic systems, shallowing and fi nal infi lling of the basin may be attributed to reduced subsidence rates in the latest part of post-rift phase of basin development (pavelić, 2001). beside the differences a notable similarity in modal composition among sands of the cernik unit and underlying andraševec and nova gradiška units indicates their common figure 6: sketch map of the pannonian basin system and its surroundings (b) simplifi ed after royden (1988). (a) enlarged part of the studied area and neighbouring mountains. transport directions and source areas for the clastic detritus of older miocene (a) and younger miocene and pliocene (b) sediments of dilj gora mt. geologia croatica 64/2geologia croatica 130 (alpine-carpathian) provenance. however, the presence of gravel, sporadic poorer sorting of detritus and occurrence of carbonate detritus (dolomite), suggests that part of the detritus did not undergo signifi cant transport, and is of local origin. namely, some blocks in the southwest part of the pb were uplifted as a result of compression at the end of the miocene, a process which intensifi ed later in the pliocene when the cernik unit was deposited (jamičić, 1995; tomljenović & csontos, 2001; márton et al., 2002). the erosion of these uplifted blocks, together with material arriving from the alps and carpathians, produced detritus for the cernik unit (fig. 6b). this is a prelude to the formation of new sources from the south at the end of the pliocene(?) and during the quaternary, evidenced by chert pebbles at the top of the završje-i and završje-ii sections. the investigation showed that the clastic material deposited during the neogene in the area of dilj gora mt. has various textural characteristics and diverse modal compositions and provenance. these differences can not only be attributed to differing source rock compositions and locations of source areas, but are also the product of different controls on sedimentation. the most important controls were varying rates of subsidence and extension of the pb interrupted by compressional events, water-level changes in the pb connected with global sea-level changes and infi lling by delta progradation. 6. conclusions the detritus of the oldest, lower miocene ravan unit is mineralogically and texturally immature, brought dominantly from the south, and derived by weathering of sedimentary and metamorphic rocks from the internal dinarides. motajica mt. located southwest of dilj gora mt. in northern bosnia, is the most logical source area since it is composed of all the rock varieties found in the clastic detritus of the ravan unit. detritus of the lower–middle miocene tuk unit is mineralogically and texturally immature and originated by the weathering of acid magmatic and metamorphic rocks. most probably it is a mixture of material from the internal dinarides, and material of local origin (požeška gora and dilj gora mts.). the origin of clastic material of the ravan and tuk units could be related to uplift of the internal dinarides before and during the early miocene, and to the formation of elongated depressions along the southern margin of the pb, in their early syn-rift phase. in most parts of dilj gora mt. during the middle miocene (zdenci, dubovik and glogovica units) carbonate clastic detritus was deposited. this detritus formed by the accumulation of the remains of fossil marine organisms in the southern, marginal parts of central paratethys. the appearance of acid volcanic detritus in the dubovik unit may be linked to the pre-badenian and badenian volcanism in dilj gora mt. area. only in the kasonja unit, in the western part of dilj gora mt., was deposition of clastic detritus signifi cant. this detritus was derived from granitoids, metamorphic and sedimentary rocks. the sources of this material were most probably the pb basement rocks of the neighbouring slavonian mts. (mts. papuk, krndija, psunj, požeška gora) or the internal dinarides of northern bosnia (motajica mt.). the older part of the late miocene area of dilj gora mt. (croatica and pavlovci units) composed of limestone and marl was not under the signifi cant infl uence of clastic material. rare carbonate clastic detritus most probably originated from the local hinterland, uplifted during compression at the end of the sarmatian in the post rift phase of basin development. the detritus of younger late miocene (the andraševec and nova gradiška units) is of uniform composition, and is mineralogically and texturally mature. it was derived by weat hering of different metamorphic rocks and older sedimentary rocks of the alps and carpathians. this material was transported into the southern part of the pb as a consequence of the progradation of clastic systems caused by reduction of subsidence rates of the pb in late post-rift phase of its development. most of the detritus of the pliocene cernik unit has the same alpine-carpathian provenance as the detritus of the andraševec and nova gradiška units. only a small part of the detritus was formed by weathering of sedimentary rocks from local blocks uplifted at the end of the miocene as a result of a new compression phase in the pb. acknowledgment this study was supported by the ministry of science, education and sports, project no. 181-1811096-1093 “basic geological map of republic croatia 1:50 000” and project no. 119-1191155-1159 “evolutionary changes of the dinarides from subduction to modern adriatic beaches”. we thank all members of the “pannonian team”, that worked on dilj gora mt. between 2004 and 2006. we are particularly grateful to ivo suša (croatian geological survey) for help with drawings and borna lužar-oberiter (fa culty of science, university of zagreb) for language editing. the authors acknowledge thamó-bozsó edit (geological institute of hungary, budapest) and to an anonymous review er for their useful comments and suggestions which substantially improved the submitted manuscript. references belak, m., sarkotić-šlat, m. & pavelić, d. (1991): an occurrence of badenian rhyolitic volcanoclastic rocks from middle parts of mt. dilj (eastern croatia).– geol. vjesnik, 44, 151–159. croatian geological survey (2009): geological map of croatia 1:300 000. csontos, l. (1995): tertiary tectonic evolution of the intra-carpathian area: a review.– acta vulcanol., 7, 1–13. horváth, f. (1995): phases of compression during the evolution of the pannonian basin and its bearing on hydrocarbon exploration.– mar. petrol. geol., 12, 147–154. jamičić, d. (1995): the role of sinistral strike-slip faults in the formation of the structural fabric of the slavonian mts. (eastern croatia). – geol. croat., 48, 155–160. kovačić et al.: composition and provenance of neogene sedimentary rocks of dilj gora mt. (south pannonian basin, croatia) geologia croatica 131 jamičić, d. & brkić, m. (1987): osnovna geološka karta sfrj 1:100000 list orahovica l33–96 [basic geological map of sfry 1:100000, orahovica sheet – in croatian].– inst. za geol. istraž., zagreb, sav. geol. zavod, beograd. jamičić, d., brkić, m., crnko, j. & vragović, m. (1987): osnovna geološka karta sfrj 1:100000. tumač za list orahovica l33–96 [basic geological map of sfry 1:100000, geology of the orahovica sheet – in croatian].– inst. za geol. istraž., zagreb, sav. geol. zavod, beograd, 1–72. juhász, g. (1991): lithostratigraphical and sedimentological framework of the pannonian (s.l.) sedimentary sequence in the hunga rian plain (alföld), eastern hungary.– acta geol. hung., 34/1–2, 53–72. juhász, g. & magyar, i. (1992): review and correlation of the late neogene (pannonian s.l.) lithofacies and mollusc biofacies in the great plain, eastern hungary.– földtani közlöny, 122/2–4, 167–194. korolija, b. & jamičić, d. (1989): osnovna geološka karta 1:100000. tumač za list našice l34–85 [basic geological map of sfry 1:100000, geology of the našice sheet – in croatian].– geol. zavod, zagreb, sav. geol. zavod, beograd, 1–40. kováč, m., nagymarosy, a., oszczypko, n., csontos, l., slaczka, a., marunteanu, m., matenco, l. & márton, e. (1998): palinspatic reconstraction of the carpathian-pannonian region during the miocene.– in: rakus, m. (ed.): de velop ment of the western carpathians. mineralia slov. monogr., 189–217. kovačić, m. (2004): sedimentologija gornjomiocenskih naslaga jugozapadnog dijela panonskog bazena [sedimentology of the upper miocene deposits from the southern part of the pannonian basin – in croatian with english summary].– unpubl. phd thesis, university of zagreb, 203 p. kovačić, m. & grizelj, a. (2006): provenance of the upper miocene clastic material in the southwestern part of the pannonian ba sin.– geol. carpath., 57, 495–510. kovačić, m., peh, z. & grizelj, a. (2009): discriminant function analysis of upper miocene and pliocene sands from the southwestern part of the pannonian basin system, croatia.– geol. croat., 62/3, 189–200. doi: 10.4154/gc.2009.12 kovačić, m., avanić, a., bakrač, k., hećimović, i., filjak, r. & morić, a. (2005): gornjomiocenski sedimenti dilj gore (late miocene sediments of dilj mt.).– proceedings of the 3rd croatian geological congress, abstracts book, 77–78. kovačić, m., zupanič, j., babić, lj., vrsaljko, d., miknić, m., bakrač, k., hećimović, i., avanić, r. & brkić, m. (2004): lacustrine basin to delta evolution in the zagorje basin, a pannonian sub-basin (late miocene: pontian, nw croatia).– facies, 50, 19–33. magyar, i., geary, d.h. & müller, p. (1999): palaeogeographic evolution of the late miocene lake pannon in central europe.– palaeogeogr., palaeoclimatol., palaeoecol., 147, 151–167. doi: 10.1016/s0031-0182(98)00155-2 márton, e., pavelić, d., tomljenović, b., avanić, r., pamić, j. & márton, p. (2002): in the wake of a counterclockwise rotating adriatic microplate: neogene paleomagnetic results from northern croatia.– int. j. earth sci., 91, 514–523. doi: 10.1007// s00531-001-0249-4 mattick, r.e., phillips, r.l. & rumpler, j. (1988): seismic stra tigraphy and depositional framework of sedimentary rocks in the pannonian basin in the southeastern hungary.– in: royden, l.h. & horváth, f. (eds.): the pannonian basin. a study in basin evolution. aapg memoir, 117−145. menge, m.a. & maurer, h.f.w. (1992): heavy minerals in colour.– chapman and hall, london, 1−151. mutić, r. (1990): korelacija kvartara istočne slavonije na osnovi podataka mineraloško–petrografskih analiza (istočna hrvatska, jugoslavija). dio ii: lesni ravnjak.– acta geol., 20, 29–80. mutić, r. (1993): korelacija kvartara istočne slavonije na osnovi podataka mineraloško–petrografskih analiza (istočna hrvatska). dio iii: slavonsko–srijemska potolina.– acta geol., 23, 89– 119. mutić, r. & dmitrović, r. (1991): akcesorni glaukofan u miocenskim naslagama hrvatskog zagorja, samoborske gore, medvednice i dilj gore (hrvatska).– geol. vjesnik, 44, 89–119. najdenovski, j. (1988): dubinski geološki odnosi i razvitak struktura u tercijarnim sedimentima požeške kotline [deep geological relations and development of structures in the tertiary sediments of the požega basin – in croatian].– unpubl. phd thesis, university of zagreb, 135 p. pamić, j., tomljenović, b. & balen, d. (2002): geodinamyc and petrogenetic evolution of alpine ophiolites from central and nw dinarides: an overview.– lithos, 65, 113−142. doi: 10.1016/ s0024-4937(02)00162-7 pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.– basin res., 13, 359–376. doi: 10.1046/j.0950-091x2001.00155.x pavelić, d. (2002): the south-western boundary of central paratethys.– geol. croat., 55/1, 83–92. pavelić, d. & kovačić, m. (1999): lower miocene alluvial deposits of the požeška mt. (pannonian basin, northern croatia): cycles, megacycles and tectonic implications.– geol. croat., 52, 67–76. pavelić, d., miknić, m., & sarkotić šlat, m. (1998): early to middle miocene facies succession in lacustrine and marine environments on the southwestern margine of the pannonian basin system.– geol. carpath., 49, 433–443. pikija, m. (2004): stratigrafska korelacija naslaga područja okučanipožega-slavonski brod [statigraphic correlation of sediments in the okučani-požega-slavonski brod area – in croatian].– unpubl. report, fond str. dok. br. 17/04. inst. za geol. itraž., zavod za geologiju, zagreb. pikija, m., vrsaljko, d., miknić, m., horvat, m., galović, i. & slovenec, d. (2005): sedimenti nižeg miocena dilj gore (lower part of miocene deposits of dilj mt.).– proceedings of the 3rd croatian geological congress, abstracts book, 113−114. royden, l.h. (1988): late cenozoic tectonics of the pannonian basin system.– in: royden, l.h. & horváth, f. (eds): the pannonian basin a study in basin evolution. the american association of petroleum geologists and the hungarian geological society. aapg memoir, 45, 27−48. royden, l.h. & horváth, f. (1988): the pannonian basin. a study in basin evolution. the american association of petroleum geologists and the hungarian geological society.– aapg memoir, 45, map 8. rögl, f. (1996): stratigraphic correlation of the paratethys oligocene and miocene.– mitt. gesell. geol. ber gbaust. österr., 41, 65–73. saftić, b., velić, j., szantó, o., juhász, gy. & ivković, ž. (2003): tertiary subsurface facies, source rocks, and hydrocarbon reservoirs in the sw part of the pannonian basin (northern croatia and south-western hungary).– geol. croat., 56, 101–122. steininger, f.f., müller, c. & rögl, f. (1998): correlation of central paratethys, eastern paratethys and mediterranean neogene stages.– in: royden, l.h. & horváth, f. (eds.): the pannonian basin a study in basin evolution. the american association of petroleum geologists and the hungarian geological society. aapg memoir, 45, 79−87. geologia croatica 64/2geologia croatica 132 stevanović, p.m. & eremija, m. (1977): geological characteristics of the pannonian and pontian of bosnia and herzegovina.– in: čičić, s. (ed.): geology of bosnia and herzegovina, book iii, periods of cenozoic. geoinženjering, sarajevo, 163–216. šimunić, an. & šimunić, al. (1987): the reconstruction of neotectonic occurrence in northwestern croatia based on analyses of pontian sediments.– jazu, zagreb, 431, 22, 155–177. šparica, m. (1985): geološki odnosi, izrada i ispitivanje istražne bušotine na termalnu vodu đakovačka breznica-1 [geological relations, development and testing of exploration well in the thermal water, đakovačka breznica-1 – in croatian].– unpubl. report, fond struč. dok. br. 353/85. inst. geol. istraž., zavod za geologiju, zagreb. šparica, m. & crnko, j. (1973): geologija zapadnog dijela dilj gore.– geol. vjesnik, 26, 83-92. šparica, m., juriša, m., crnko, j., šimunić, an., jovanović, č. & živanović, d. (1980a): osnovna geološka karta sfrj 1:100000, list nova kapela l33–108 [basic geological map of sfry 1:100000, nova kapela sheet – in croatian].– inst. za geol. istraž., zagreb & inst. za geol., sarajevo, sav. geol. zavod, beograd. šparica, m., juriša, m., crnko, j., šimunić, an., jovanović, č. & živanović, d. (1980b): osnovna geološka karta sfrj 1:100000. tumač za list nova kapela l33–108 [basic geological map of sfry 1:100 000, geology of the nova kapela sheet – in croatian].– inst. za geol. istraž., zagreb & inst. za geol., sarajevo, sav. geol. zavod, beograd, 1−55. šparica, m., buzaljko, r. & mojićević, m. (1987a): osnovna geološka karta sfrj 1:100000, list slavonski brod l34–97 [basic geological map of sfry 1:100000, slavonski brod sheet – in croatian].– geološki zavod, zagreb & geoinženjering, sarajevo. sav. geol. zavod, beograd. šparica, m., buzaljko, r. & pavelić, d. (1987b): osnovna geološka karta sfrj 1:100000, list slavonski brod l34–97 [basic geological map of sfry 1:100000, geology of the slavonski brod sheet – in croatian].– geološki zavod, zagreb & geoinženjering, sarajevo. sav. geol. zavod, beograd, 1−56. šparica, m., pavelić, d., miknić, m. & brkić, m. (1988): miocenski biolititi u području dilj gore (slavonija, istočna hrvatska) [miocene biolithites on dilj mountain (slavonia, north croatia) – in croatian].– geol. glasnik, posebna izdanja, 6, 243–251, titograd. thamó-boszó, e. & juhász, g. (2002): mineral composition of upper miocene-pliocene (pannonian s.l.) sands and sandstones in the different sedimentary subbasins in hungary. – geol. carpath., 53, spec. issue, cd with extended abstracts. thamóné bozsó, e., juhasz, gy. & kovacs lajos, ó. (2006): the mineral composition of the pannonian s.l. formations in the hungarian plain (i). the characteristics and origins of the pannonian s.l. sands and sandstones.– földtani közlöny, 136/3, 407–429. thamó bozsó, e. & kovács, ó. (2007): evolution of quaternary to modern fluvial network in the mid-hungarian plain, indicated by heavy mineral distributions and statistical analysis of heavy mineral data.– földtani közlöny, 136/3, 491–524. tomljenović, b. & csontos, l. (2001): neogene–quaternary struc tures in the border zone between alps, dinarides and pannonian basin (hrvatsko zagorje and karlovac basins, croatia).– int. j. earth sci. 90, 560–578. doi: 10.1007//s005310000176 vakarcs, g., vail, p.r., tari, g., pogácsás, gy., mattick, e.r. & szabó, a. (1994): third-order middle miocene-early plio cene depostional sequences in the prograding delta complex of the pannonian basin.– tectonophysics, 240, 81–106. varićak, d. (1966): pertrološka studija motajičkog granitnog masiva [petrological study of motajica’s mt. granitic massive].– posebno izdanje geološkog glasnika, sarajevo, 9, 1–170. manuscript received december 08, 2010 revised manuscript accepted march 24, 2011 available online june 09, 2011 www.geologia-croatica.hr abstract the sedimentary record is an inexhaustible repository of information on global climates. the study of documents of past climate change may help us to understand not only the causes and presumable effects of the current change, but also to reveal the often complex and subtle mechanisms regulating the system. ferrallitic soils and soil-derived sediments (=bauxites) are generally considered as best climate-indicators on dry-land. their frequency distribution through geologic time shows pronounced positive anomalies coincident with greenhouse periods of earths’ history. it is proposed that intense ferrallitic weathering instead of being simply the passive product of the greenhouse could be also one of the negative feedbacks of the system counteracting warming by contributing to the pump-down of greenhouse gases from the atmosphere. in this way it helped to decelerate both the carbon-cycle and the hydrological-cycle. the mass-transfer of oxygen from the atmosphere to the lithosphere is tentatively considered as an additional negative feedback acting to slow down oxidative weathering on land. it is suggested that the study of bauxites and correlative anoxic sediments in the oceans should be used to reveal details of the above complex regulation mechanism. keywords: ferrallitic weathering, bauxites, climate change, hydrological cycle, terrestrial carbon pump article history: received september 26, 2015 revised and accepted december 11, 2015 avaliable online february 29, 2016 79-87 8 figs. 1 tab. doi:10.4154/gc.2016.07 1. introduction more than 25 years ago, an igcp project no. 287 „tethyan bauxites” was initiated and enthusiastically joined by all the karst-bauxite geologists of the mediterranean and beyond. along with prof. goran durn (then a student), his supervisor prof. l. palinkaš and the late prof. šinkovec, prof. jurković was among the participants sharing his experience and ideas about the geology and the bauxite deposits of the dinarids. the main goal of that project was to summarize all published and unpublished data on mediterranean karst bauxites in order to improve our understanding of the controls of bauxite genesis. at that point, tectonics was in the focus of interest, climate was taken for granted, inasmuch as humid tropical to subtropical conditions were considered as causae sine qua non of bauxite formation, providing the necessary geochemical environment of intense weathering. the localization of the deposits within the favourable climatic zone was assigned to geotectonic, geomorphologic and hydrologic factors and to the lithology of the karstic host rocks. that greenhouse conditions were of crucial importance in bringing about the anomalous abundance of bauxites in cretaceous times was acknowledged by the community of igcp-287 and tentatively exposed at eug in strasbourg 1991, then reiterated by d’argenio & mindszenty in their review on bauxites and palaeokarst in 1995. major arguments for a causal relationship existing between the frequency distribution of bauxites and globally warm, humid climatic periods of the earth history had perviously been put forward in 1982 by bárdossy, bárdossy & aleva (1990), d’argenio & mindszenty (1992) and föllmi et al. (1993). though there are also some doubts regarding the simplistic climatic interpretation of palaeoclays (eg. singer 1980;1984), or thiry (2000), there is a general agreement about the anomalous abundance of bauxites in the stratigraphic record being the signs of long-lasting warm-humid conditions in subaerially exposed areas. the aim of the present paper is to show that instead of being passive products of the greenhouse, bauxites might have acted (though in a rather subtle way), as one of the feedbacks during the development and fading of the cretaceous greenhouse. 2. bauxites reliable climate indicators the sedimentary record is an inexhaustible repository of information on global climates (eg. erhart (1955, 1966, 1967), frakes (1979), parrish (1998) and many others). all the elementary processes of sedimentary rock formations, i.e. weathering, transportation, deposition even the early stages of diagenesis are, at least to some extent, climate-controlled. mineralogy, chemistry, texture, structure of sedi mentary rocks and their characteristic fossil assemblages being the direct or indirect results of climate-dependent elementary processes, may faithfully record past climatic parametres like temperature, humidity, evaporation, hydrogeochemistry etc. however, since climate is by far not the only factor determining the final appearance of a sedimentary rock, and since all postdepositional processes (including burial diagenesis) tend to conceal or at least to modify the original climate signal potentially preserved in sedimentary particles, there are but a few really reliable climate indicators. a literature review of past climate changes may help to understand not only the causes and presumable effects of the current change, but they may also help to reveal the often complex and subtle mechanisms regulating the system. to pursue this goal it is useful first to review available data on modern climate-specific sediments such as evaporites, aeolian deposits, coral reefs and bauxites. bauxites: feedbacks of system earth at greenhouse times andrea mindszenty eötvös l. university, department of physical and applied geology; 1117 budapest, pázmány p. sétány 1/c, hungary (andrea.mindszenty@gmail.com) 80 vol. 69/1 fig 1. shows the global distribution of modern climate indicators based on parrish et al. (1982), parrish (1998), bárdossy & aleva (1990) and scotese (2001). concise and also more sophisticated reviews are available in papers by price et al. (1997a,b,) sellwood & price (1994), allen et al. (1994). they all confirm that in one way or another, all sediments are indeed climate-sensitive. there are two of them that seem to be properly restricted to one particular climatic zone, as bauxites and coral reefs occur exclusively in the tropics. in other words, in modern times, the best tropical climate indicators are coral reefs in the oceans and ferrallitic soils (oxisols i.e. eqivalents of bauxites in the stratigraphic record) on dryland, and at least as far as ferrallitic soils are concerned, this must have been the situation throughout the phanerozoic. the role of bauxites as unequivocal climate indicators has been confirmed by price et al. (1997) and more recently by retallack (2010). it has to be noted, though, that most bauxites, occurring on tropical landmasses, having been exposed since mesozoic to early tertiary times, are not necessarily the products of the current climatic scenario (e.g, thiry (2000) and others). 3. bauxites and greenhouse periods it was first pointed out by bárdossy (1982), then by bárdossy & aleva (1990), d’argenio & mindszenty (1992) and more recently by retallack (2010) that the frequency distribution of bauxites through geological time shows pronounced positive anomalies coincident with the „greenhouse” periods of earth history (fig. 2). this trend is particularly well demonstrated by karst bauxites, the age of which is better constrained by the enclosing carbonates than that of those occurring in a lateritic association. when, as an example focussing on cretaceous karst bauxites and apparently contemporaneous global events, it is easy to see that even though the age-resolution of the studied phenomena is very different, bauxite-peaks are, indeed, coincident with globally high temperatures, concommittant eustatic sea-level highs, positive anomalies of world-wide igneous activity and figure 1. global distribution of climate-dependent sediments (data from bárdossy & aleva, 1990, parrish 1998, scotese, 2001). legend: b=bauxites, s=evaporites, e=aeolian sands, asterisks=coral reefs figure 2. relative abundance of bauxites in the stratigraphic record (after bárdossy & aleva 1990). (grey shading= warm wet periods) 81 mindszenty andrea: bauxites: feedbacks of system earth at greenhouse times abundant oceanic anoxia (fig. 3). the correlation of bauxitetype weathering with peak global temperatures and sea-level may arise simply from the fact that all are direct consequences of the cretaceous greenhouse. the correlation with the peak of igneous activity is certainly indirect, either because of the enhancement of atmospheric co2 and therefore a contribution to the greenhouse (larson (1991), larson & erba (1999), kuroda et al. (2007), which is also favourable for bauxites, or because of the release of large amounts of volcanic dust, providing the necessary source material for bauxites (marić, (1966); d’argenio (1970); bárdossy et al. (1977); d’argenio & mindszenty, (1991, 1992). it was this latter coincidence which at the time of igcp-287 directed our attention to the relationship of bauxites and geodynamics, extensively discussed by bárdossy (1973), bárdossy & dercourt (1990), combes & bárdossy (1994), d’argenio & mindszenty (1991, 1995), mindszenty et al. (1996). peak abundance of cretaceous bauxites in fact coincides with subduction and subsequent orogenic deformation all along the alp-himalayan orogenic belt. the obvious reason for the coincidence with orogenic deformation is the requirement of exposed land for continental weathering. at times of globally high sea-level as in cretaceous times, the only way to provide for subaerial weathering (sufficiently long-lasting for bauxites to form) is the tectonically controlled uplift of large previously submarine areas. in fact, cretaceous karst bauxites occur on tectonically affected shallow-water carbonate platform sectors all over the tethyan realm and beyond (figs. 3 and 4). the correlation of bauxites with oceanic anoxia deserves special attention, because it connects two obviously climatically controlled, but seemingly unrelated, if not antagonistic phenomena: products of strongly oxidizing chemical weathering on land (which efficiently destroys/removes organic matter in/ from the soil, (e.g patel-sorrentino et al. (2007) and oxygen-deficient, organic-rich sediments in the sea. anoxic sediments form in places where the sediment surface intersects the oxygen-minimum zone of the oceanic water-mass. at greenhouse-times, when organic productivity is particularly high in the surface water-layer this may also happen in shallow shelf regions or else in partially closed compartments of the deep sea, where ventilation is insufficient to replace dissolved oxygen consumed by organic decay (fig. 5) (e.g. schlanger & jenkyns (1976); weissert & mckenzie (1979); jenkyns (1980); and many others). figure 3. cretaceous bauxites, geotectonics and paleoenvironmental factors (basic data from scotese’s paleomap project (2002), larson, 1990 and d’argenio & mindszenty (1994)) (white asterisks: position of the cartoons showing the geodynamic settings where bauxites occur). 82 vol. 69/1 4. bauxites and oceanic anoxic events – the terrestrial and the oceanic carbon pump however unrelated those highly oxidized ferrallitic soils and anoxic sediments may seem to be, they may not only coincide in time but occur in close juxtaposition, as well. this is particularly well demonstrated by the dinaricadriatic-apenninic domain in cretaceous times (see fig. 6), where bauxites on the exposed sectors of the campanialucania, abruzzi and apulia carbonate platforms correlate very well with anoxic sediments in the umbria-marche basin and in certain adriatic shelf sectors (bárdossy et al. (1977); jenkyns (1980); and fig. 6). when looking into the details of the geochemistry of anoxia and ferrallitic weathering both the apparent coincidence and the above juxtaposition may be explained. 2kalsi3o8 + 2h2co3 + 9h2o → 2k+ + 2hco3 + al2si2o5 (oh)4 + 4h4sio4 (1) (felspar) (kaolinite) al2si2o5 (oh)4 + 5h2o → 2al(oh)3 + 2h4sio4 (2) (kaolinite) (gibbsite) anoxic sedimentation in the oceans is considered as the essential part of the “biological carbon-pump” (eg. volk & hoeffert (1985) in as much as co2 taken up from air/water by photosynthesizing organisms is efficiently transferred from the atmosphere to the lithosphere when dead phytoplankton reaches the ocean-bottom, becomes buried and thus withdrawn for a long time from the carbon cycle (cf. with jenkyns (1980); schlanger et al. (1987); and fig. 5). as pointed out by berner et al. (1983), berner (1991), amiotte suchet & probst (1994), velbel (1993); lasaga et al. (1994); and several others, chemical weathering also consumes co2 on land. so we may agree with berner et al. (1983), that in addition to the well-known carbon-pump, driven by anoxic sedimentation in the oceans, there is another, land-based (or terrestrial) carbon-pump, operated by chemical weathering likewise transferring carbon from the atmosphere into the lithosphere i.e. into soils and sediments. as shown by amiotte suchet & probst (1994), more intense chemical weathering on the continents results in higher co2 consumption so periods with abundant ferrallitic soils (bauxites) may be signs of particularly efficient performance of the terrestrial carbon-pump. the co-incidence of the anomalous abundance of anoxic sediments and bauxites in cretaceous times as pointed out by d’argenio & mindszenty (1992), foellmi et al. (1993), jenkyns (2003) suggests that the two carbon pumps may somehow be coupled and when that happens, their effects may be greatly enhanced (fig. 7). similar to foellmi’s suggestion who, when explaining the anomalies of the phosphorous-cycle, introduced the idea of the vitamin (volcanicaly induced transfer and accelerated mineralization of inhibiting nutrients) periods (foellmi et al. (1993) and in agreement with jenkyns (2003) who called attention to the increased amounts of continental runoff at times of peak greenhouse periods, we propose a cretaceous scenario where nutrients (i.e. k, p, ca, mg, na and also fe) liberated by chemical weathering on land, reaching the ocean in solution by groundwater flow, and also by surface runoff (as fine hydrated particles) or as airborn dust, would significantly contribute to the increase of organic production in the photic figure 4. areal disribution of cretaceous bauxites. base map from ziegler (1988). key: 1 continental crust, 2 carbonate platforms/open shelves, 3 pelagic/hemipelagic basins, 4 terrigeneous shelves, 5 deformed belts and ophiolites, 6 oceanic crust anjd sediments, 7 tethyan karst bauxites (insert: world bauxites karst+laterite), am armorican massif, mc -massif central, bm bohemian massif, ea eastern alps, tr transdanubian range, mp -moesia, he -hellenids, hk dinaric high karst, ap -apulia, la latium-abruzzi, lc campania-lucania, cs corsica-sardinia, py pyrenees, lp languedoc-provence, ibm iberian massif, 30o estimated paleolatitudes (based on parrish et al., 1982, márton & márton, 1985 and sclater et al., 1977). 83 mindszenty andrea: bauxites: feedbacks of system earth at greenhouse times zone (fig. 8). in this way they may „prepare the ground” for anoxic sedimentation and thus trigger the withdrawal of excess carbon from the atmospheric reservoir. calculations of liu et al. (2010) for the recent world seem to support this idea even though they emphasize the need for further more detailed studies. among the nutrients introduced into the ocean, iron seems to play a rather particular role. the idea that fe, being a limiting nutrient for organisms including eg. chrysophyta and bacillariophyta, is likely to be decisive from the point of view of the organic productivity of the oceans is more and more popular. as pointed out first by martin & gordon (1988) fe-deficiency might result in zero productivity, even if all other conditions were favourable for life (=high nutrient low chlorophyll areas). they suggested that in such lowproductivity sectors of the oceans “iron-fertilization” would dramatically increase chlorophyll production. the hypothesis was tested in the late ‘80’s in the pacific in the frames of the so called ironex experiment (martin & fitzwater (l988). that dust may be blown out from tropical areas and carried all across the atlantic by the trade winds as far as bermuda was previosuly detected by muhs et al. (1990), and that south african dust may reach the south indian ocean was shown by piketh et al. (2000). it was also shown that dust contains not only fine grained muscovite, felspar and quartz but also abundant iron-rich alteration products (herwitz & muhs (1995) or herwitz et al. (1996), etc.). that together with clay particles iron-rich particulate material may be introduced into the ocean by river runoff has also been known for a long time (e.g. carrol (1958); poulton & raiswell (2002). the possibility of natural iron-fertilization of the surface ocean by fine dust-related particulate fe-oxides converted into bio-available iron by photochemical reactions was put forward by joos et al. (1991), tortell et al. (1999), gnanadesikan et al. (2003), jickells et al. (2005), rijkenberg et al. (2005). we have good reason to think that after long periods of particularly intense ferrrallitic weathering on land (as at grenhouse times), when climate change begins and formerly humid areas gradually change for drier environments, rain forests give way at least partially to savannah type vegetation on the continents. as erosion is increased first by torrential figure 6. areal distribution of bauxites and anoxic sediments in the cretaceous of the dinaride and appenine sectors of the mediterranean (base map and anoxic sediments from jenkyns, 1980). figure 5. the oceanic carbon pump. figure 7. coupling the terrestrial and the oceanic carbon pump. figure 8. the cretaceous scenario with nutrients dissolved from the ferrallitic soil blanket and transported from the continent to the ocean as solutes by groundwater-flow and runoff and as particulate material – by runoff and by wind. 84 vol. 69/1 rains then by wind, the amount of river-born particulate iron and later on also of airborn ferrallitic dust may be increased and transported over the oceans, contributing to the increase in organic productivity of the surface waters. in this way, the performance of the marine carbon pump becomes greatly enhanced i.e. ferrallitic weathering on land helps to contribute to the slow-down of the carbon cycle. this „natural ironfertilization” mechanism as suggested also by mindszenty & bárdossy in 2008 would explain both the areal and temporal coincidence of bauxites and anoxic sediments at greenhouse times, i.e. also in the cretaceous as proposed above. 5. bauxites, the hydrological cycle and the composition of the atmosphere molecular ratios of co2 and h2o in the above simple equations (see (1) and (2) suggest that when the end-product of ferrallitic weathering is bauxite (rich in gibbsite and goethite), weathering means efficient transfer not only of co2 but also of the greenhouse-„accelerator” h2o from the atmosphere into the lithosphere. this is how it may contribute to the deceleration of not only the carbon cycle but also the water-cycle. at the same time ferrallitic weathering also consumes oxygen so in many ways it interferes with the composition of the atmosphere (cf with tardy et al. (1989), bergman et al. (2004), berner (2005). oxygen is used in the oxidation of primary silicate minerals, organic matter and eventually pyrite. according to the calculations of combes & bárdossy (1995), the oxygen content of any weathered rock in the ferrallitic suite is, on the average, 10 % higher than that of its fresh parent material. table 1. shows the relative amount of atmospheric oxygen fixed in cretaceous ferrallitic weathering products, as calculated by combes & bárdossy. as to the role of water-vapour in the atmosphere, there has been some debate among climatologists regarding its efficiency as a feedback mechanism amplifying/accelerating climate change when global warming has already begun sherwood & meyer (2006). though the magnitude is still difficult to estimate, nowadays there is a general agreement, as a result of model simulations and satellite observations, that it works as a strongly positive feedback indeed (dessler & sherwood, 2009). when focussing our attention on the relative proportions of water molecules participating in the afore-mentioned equations (1), (2), the amount of water fixed in the alteration products is apparent at first glance. interestingly enough, unlike the role of silicate weathering in regulating the carbon-cycle previosuly discussed by berner et al. (1983), the possibility of hydrolithic i.e. ferrallitic weathering regulating the water-cycle (particularly when reaching the bauxite stage) has not been discussed by either of the available moisture budgets (eg. tardy et al. (1989), trenberth et al. (2006), liu et al. (2010). a very simple minimum estimate of water chemically bound in cretaceous ferrallitic weathering products can be attempted when taking into account the extent of continental areas for a cretaceous palaeogeography (suggested as 20 502 x 103 km2 by tardy et al. (1989) and calculating with only 10 metres of weathered material accumulated between 0 to 10 degrees latitudes n & s. this is an obvious underestimation since we know very well that in recent tropical areas ferrallitic weathering profiles may be several tens of metres thick, however they are mineralogically heterogeneous, so for the sake of simplicity it is easier to calculate here with a reduced thickness and with a homogeneous mineralogy as shown below). the average bulk density of the weathering product is taken as 2.4 g/cm3 (based on posgay (1967), bárdossy & aleva (19909 and hill et al. (2006). the amount of water chemically bound in such a 10 m thick weathered mantle can be calculated on the basis of the water-content of a 50-50% mixture of the two most abundant alumina minerals (gibbsite and boehmite) while the water bound in goethite and kaolinite is ignored at this point. this is again an oversimplification which may, however, be compensated for by the reduced thickness introduced above. based on the data of hill et al. (2006), and brown et al. (1953) for the water content of the alumina minerals (34.65 % for gibbsite and 15.02 % for boehmite), when calculating with an average water content of 24.84 weight percent, the resulting total amount of water chemically bound in ferrallitic weathering products of the cretaceous world is 122.225x103 km3. it is almost equivalent to the amount of water estimated by trenberth et al. (2007) in their global water budget recently stored as 122x103 km3 „soil moisture” in the land reservoir and regarding its order of magnitude it is even comparable to the amount of water stored in lakes and rivers of the current land reservoir (178 x103 km3). therefore, even this rough estimate calls attention to the role of hydrolithic weathering in the global water cycle. continental runoff is, as a rule calculated by looking for the difference between the amounts of rainfall and evapotranspiration (eg. tardy et al. (1989), sometimes also taking into consideration changes of soil moisture and groundwater (trenberth et al., 2007). however it is generally ignored that the part of what is supposed intensity of weathering (m/myr) 2 m/myr 3 m/myr 4 m/myr 5 m/myr percent oxygen bound in bauxite (oxbx/oxatm x 0.1) (from albian to cenomanian, in 23 myrs) 4.40% 6.50% 8.70% 10.90% percent oxygen bound in bauxite (oxbx/oxatm x 0.1) (from turonian to senonian, in 26 myrs) 4.50% 6.70% 8.90% 11.20% table 1. combes & bárdossy (1995) 85 mindszenty andrea: bauxites: feedbacks of system earth at greenhouse times qualified as „runoff” is in fact transferred into the lithosphere and thus in the long run withdrawn from the water cycle. it is suggested that over geological time scales the latter helps to remove not only carbon but also substantial amounts of water from the atmosphere. in other words: intense chemical weathering may substantially contribute to the slow down not only of the accelerated carbon-cycle but also the accelerated hydrological cycle. in addition, ferrallitic weathering may counteract even one of the inherent positive feedbacks of greenhouse-warming, namely the production of co2 on oxidation of continental organic matter (peat). as pointed out above, combes & bárdossy (1995) suggested that the amount of oxygen bound in bauxites may be about 10 percent higher than in any of their fresh parent rocks. they calculated the quantity of oxygen bound in bauxites formed throughout cenomanian and turonian-senonian times and compared the data to the quantity of atmospheric oxygen of each of those periods (as given by budyko et al. (1987). they concluded that depending on the rate and the duration of the weathering process, about 4 to 11 pecent of atmospheric oxygen may have become chemically bound to the alteration product, i.e. transferred from the atmospheric to the lithospheric reservoir. this is how ferrallitic weathering could have contributed to the decrease of the amount of free oxygen available for the oxidation of more terrestrial organic matter. 6. bauxites: positive or negative feedbacks? conclusions even though their effect may be modest, it is suggested that in the long run, bauxites are undoubtedly one of the negative feedbacks: they release nutrients into the ocean (both via groundwater-flow and by air) and this way may help to intensify the oceanic carbon pump (i.e. contribute to the drawdown of co2 from the atmosphere). by chemically fixing part of the oxygen content of the atmosphere they may also help to decrease the rate of oxidation of terrestrial organic matter and thus slow down the rate of additional co2-release. by transferring h2o into the lithospheric reservoir they may also help to decelerate the hydrological cycle. to improve our understanding of system earth, its controlling mechanisms and its feedbacks it is inevitable to look into the past and search for the documents of even minor feedbacks in the stratigraphic record. as the oceanic carbonpump was recognized by looking into the details of anoxic sedimentation and its effects on the carbon-budget of the system (premoli-silva et al. (1999), erba (2004) and others), it is very likely that additional, more detailed and quantitative study of bauxites may contribute to an improved understanding of the operation of the land-based h2o (and carbon) pump as well. it is suggested that bauxites (palaeoferrallitic soils) were not only passive products of phanerozoic greenhouse-episodes but they were parts of the feed-back loops helping the system to return to equilibrium after each large-scale greenhouse episode. this complies very well with the ideas of berner et al. (1983), foellmi et al. (1992), yuan gao et al. (2003) and ridgewell et al. (2002) regarding the role of chemical weathering in controlling the carbon-budget of system earth. indeed, the comparative study of bauxites, coeval anoxic sediments and modelled palaeowind trajectories (as in linen & heath (1981), would certainly disclose hitherto unknown details of this complex interaction. closing remark: after having submitted this manuscript i received a copy of the paper of lechler et al. (2015) in which the authors present convincing isotope-geochemical evidence for the importance of silicate weathering in sequestering atmospheric co2 during one of the cretaceous oceanic anoxic events (oae 1a, selli), so at least part of the theory seems to work also in practice. acknowledgement the efforts of editor alisa martek, l. palinkaš and another anonymous reviewer to improve the paper are greatly appreciated. thanks are due to the community of the former igcp-287, particularly b. d’argenio and the late prof. bárdossy for thought provoking discussions on the subject and to o. piros for grooming the figures. references allen, j.r.l., hoskins, b.j., valdes, p.j., sellwood, b.w. & spicer, r. (1994): paleoclimates and their modelling with special reference to the mesozoic era.− springer, 140 p. amiotte suchet, p. & probst, j.l. (1995): a global model for presentday atmospheric/soil co2 consumption by chemical erosion of continental rocks (gem_co2).− tellus, 7b, 273−280. gnanadesikan, a., sarmiento, j.l. & slater, r.d. (2003): effects of patchy ocean fertilization on atmospheric carbon dioxide and biological production.− global biogeochemical cycles, 17/2, 1050. doi: 10.1029/2002gb001940 arthur, m.a., schlanger, s.o. & jenkyns, h.c. (1987): the cenomanian-turonian oceanic anoxic event,ii. palaeogegraphic controls on organic matter production and preservation.− geol. soc. london, spec. publ., 26, 401−420. bárdossy, gy. (1973): bauxite formation and plate tectonics.− acta geol. acad. sci. hung., 17/(1−3), 141−154. bárdossy, gy. & dercourt, j. (1990): les gisements des bauxites tethysiennes (mediterranée, proche et moyen orient): cadre paléogeographique et controls genetiques. bull. soc. geol. france, 8, 4/6, 869−888. bárdossy, gy. (1982). karst bauxites. bauxite deposits on carbonate rocks.− developments in economic geology, 14. elsevier, amsterdam, 441 p. bárdossy, gy., boni, m., dall’aglio, m., d’argenio, b. & pantó, gy. (1977): bauxites of peninsular italy. composition, origin and geotectonic significance. monogr, ser. on miner. deposits, gebr. borntraeger, berlin, 15, 61 p. bárdossy, gy. & aleva, g.j.j. (1990): lateritic bauxite. developments in economic geology, 27, elsevier, amsterdam 624 p. bergman, n.m., lenton, t.m. & watson, a.j. (2004): copse: a new model of biogeochemical cycling over phanerozoic time.− amer. journ. sci., 304, 397−437. doi: 10.2475/ajs.304.5.397 berner, r.a. (1991): a model for atmospheric co2 over phanerozoic time.− amer. journ. sci., 291, 339−376. berner, r.a. (2006): geocarbsulf: a combined model for phanerozoic atmospheric o2 and co2.− geochim. cosmochim. acta, 70, 5653−5664. doi: 10.1016/j.gca.2005.11.032 berner, r.a. (2005): the carbon and sulfur cycles and atmospheric oxygen from middle permian to middle triassic.− geochim. cosmochim. acta, 69, 3211−3217. doi: 10.1016/j.gca.2005.03.021 berner, r.a., lasaga, a.c. & garrels, r.m. (1983): the carbonatesilicate geochemical cycle and its effects on atmospheric carbon dioxide over the past 100 million years.− amer. journ. sci., 283, 641−683. doi: 10.2475/ajs.283.7.641 brown, j.f., clark, d. & elliott, w.w. (1953): the thermal decomposition of the alumina trihydrate, gibbsite.− j. chem. soc., 1953, 84−88. doi: 10.1039/jr9530000084 budyko, m.j., ronov, a.b. & yanshin, a.l.(1987): history of the erath’s atmosphere. springer, berlin, 138 p. 86 vol. 69/1 carroll, d.l. (1958): role of clay minerals in the transportation of iron.− geochim. et cosmochim. acta, 14, 1−27. coale, k., johnson, k. & 17 others (1996): a massive phytoplankton bloom induced by an ecosystem-scale iron fertilization experiment in the equatorial pacific.− nature, 383, (10 october 1996), 495−501. doi: 10.1038/383495a0 combes, j.p. & bardossy, gy. (1994):. typologie et controle geodynamique des bauxites tethysiennes.− comptes rend. acad. sci. paris, t. 318, ser., ii., 359−366.. combes j.p. & bárdossy, gy. (1995): controlling influence of bauxites and laterites on the earths atmosphere.− comptes.rendus de l’academie des sciences, ser.ii., 320/2, 109−116. d’argenio, b. (1970): central and southern italy cretaceous bauxites, stratigraphy and paleogeography.− ann. inst. geol. publ. hung., 56/3, 221−233. d’argenio, b. & mindszenty, a. (1991): karst bauxites at regional unconformities and geotectonic correlation in the cretaceous of the mediterranean.− boll. soc geol. ital., 110, 85−92. d’argenio, b. & mindszenty, a. (1992): tectonic and climatic control on paleokarst and bauxites.− giorn. geol., 54/1, 207−218. d’argenio, b. & mindszenty, a. (1995): bauxites and related paleokarst: tectonic and climatic event markers at regional unconformities.− eclogae geol. helv., 88, 453−499. dessler, a.e. & sherwood, c.s. (2009): a matter of humidity.− science, 323, 1020−1021. erba, e. (2004): calcareous nannofossils and mesozoic oceanic anoxic events.− marine micropaleontology, 52/1−4, 85−106, doi: 10.1016/j.marmicro.2004.04.007 erhart, h. (1955): „biostasie” et „rhexistasie”. esquisse d’un theorie sur le role de la pedogenese entant que phenomene geologique.− c. r. acad. sci., paris, t. 241, 1218−1220. erhart, h. (1966): bio-rhexistasie, biostasie evolutives, heterostasie. importance de ces notions en geologie miniere exogene.− c.r. acad. sci. paris, t. 263, 1049−1051. erhart, h. (1967): la genese des soils entant que phenomene geologique.− masson, paris, p. 88. föllmi, k.b., weisser, t.h. & lini, a. (1993): nonlinearities in phophogenesis and phosphate-carbon coupling and their implications for global climate change.− in: wollast, r., mackenzie, f.t. & chou, l. (eds.): interactions of c, n, p and s biogeochemical cycles and global change. nato asi series i. global environmental change, vol. 4, 447−474. frakes, l.a. (1979): climates throughout geologic time.− elsevier, 310 p. frakes, l.a., francies, j.e., syktus, j.i. (1992): climate modes of the phanerozoic.− cambridge univ. press, 286 p. doi: 10.1017/ cbo9780511628948 fritz, b. & tardy, y. (1973): etude thermodynamique du systeme gibbsite, quartz, kaolinite gaz carbonique: application a la genese des podzols et des bauxites.− sci. geol. bull., 26/4, 339−367. yuan gao, song-miao fan & sarmiento, j.l. (2003): aeolian input to the ocean through precipitation scavenging: a modeling perspective and its implication for natural iron fertilization in the ocean.− journ. geoph. res., 108 no d7, 4221. doi: 10.1029/2002jd002420 gnanadesikan, a., sarmiento, j.l., slater, r.d. 82003):effects of patchy ocean-fertilization on atmospheric carbon dioxide and biological production.− global biogeochemical cycles, 17, 1050. doi: 10.1029/2002gb001940 herwitz, s.r. & muhs, d.r. (1995): bermuda solution pipe soils. a geochemical evaluation of eolian parent materials.− spec. pap. geol. soc. amer., 300, 311−323. doi: 10.1130/0-8137-2300-0.311 herwitz, s.r., muhs, d.r., prospero, j.m., mahan, s. & vaughn, b. (1996): origin of bermuda’s clay-rich quaternary paleosols and their paleoclimatic significance.− j. geoph. res., 101, nod18, 23389−23400. hill, v.g. & sehnke, e.d. (2006): bauxite.− in: kogel, j.e., trivedi, n.c., barker, j.m. & krukowski, s.t. (eds.): industrial minerals and rocks (7th edition) commodities and markets, usgs. soc. mining, metallurgy and expl., inc. (dme), 1507 p. jenkyns, hc. (1980): cretaceous anoxic events: from continents to oceans.− journ. geol. soc., 137, 171−188. doi: 10.1144/gsjgs.137.2.0171 jenkyns, h.c. (2003): evidence for rapid climate change in the mesozoic paleogene greenhouse world. phil. transact. math. phys. and engineering sci., 361, no.1810, abrupt climate change. evidence, mechanism and implications, 1885−1916. jickells, t.d., an, z.s., andersen, k.k., baker, a.r., bergametti, g., brooks, n., cao, j.j., boyd, p.w., duce, r.a., hunter k.a., kawahata, h., kubilay, n., la roche, j., liss, p.s., mahowald, n.,pprospero, j.m., ridgwell, a.j., tegen, i. & torres, r. (2005): global iron connections between desert dust, ocean biogeochemistry and climate.− science, 306, 67−71. doi: 10.1126/ science.1105959 joos, f., sarmiento, j.l. & siegenthaler, u. (1991): estimates of the effect of southern ocean iron fertilization on atmospheric co2 concentrations.− nature, 349,772−775. doi: 10.1038/349772a0 kuroda, j., ogawa, n.o., fanimizu, m., coffin, m.f., tokuyama, h., kitazalo, h. & ohkouchi, n. (2007): contemporaneous massive subaerial volcanism and late cretaceous oceanic anoxic event 2.− earth and planetary science letters, 256, 211−223. doi: 10.1016/j. epsl.2007.01.027 larson, r.l. (1991): geological consequenes of superplumes.− geology, 19, 963−966. larson, r.l. & erba, e. (1999): onset of the mid-cretaceous greenhouse in the barremian-aptian: igneous events and the biological, sedimentary and geochemical responses.− paleoceanograhy 14, 663−678. doi: 10.1029/1999pa900040 lasaga, a.c., soler, j.m., ganor, j., burch, t.e. & nagy, k.l. (1994): chemical weathering rate laws and global geochemical cycles. geochim. cosmochim. acta, 58 , 2361−2386. doi: 10.1016/00167037(94)90016-7 lechler, m., philip, a.e., von strandmann, p., jenkyns, h., prosser, g. & parente, m. (2015): lithium-isotope evidence for enhanced silicate weathering during oae 1a (early aptian selli event).− earth and planetary science letters, 432, 210−222. doi: 10.1016/j. epsl.2015.09.052 linen, m. & heath, g.r. (1981): sedimentary indicators of atmospheric activity in the northern hemisphere during the cenozoic.− palaeogeography, palaeoclimatology, palaeoecology, 36, 1−21. liu, z., dreybrodt, w. & wang, h. (2010): a new direction in effective accounting for the atmospheric co2 budget: considering the combined action of carbonate dissolution, the gobal water cycle and photosynthetic uptake of dic by aquatic organisms.− earth sci. rev., 99, 162−172. doi: 10.1016/j.earscirev.2010.03.001 marić, l. (1966): untersuchungen zur genesis der karstbauxite in den dinariden jugoslaviens.− mitt. inst. lager. rohstoff. techn. univ. berlin, 2, 1−49. martin, j.h. & gordon, r.m. (1988): northern pacific iron distribution in relation to phytoplakton productivity.− deep sea research, 35, 177−196. martin, j.h.& fitzwater, s.e. (1988): iron deficiency limits phytoplankton growth in the north-east pacific subarctic.− nature, 331, 341−343. doi: 10.1038/331341a0 márton, e. & márton, p. (1985): tectonic and paleoclimatic aspects of paleomagnetism studies in the transdanubian central mountains.− acta geol. hung., 28/1−2, 59−70. mindszenty, a. & bárdossy, gy. (2008): bauxites as potential feedback mechanisms of system earth: an unconventional view of the relationship between bauxites and global change.− proc. xth congress icsoba, 28-30 november 2008, bhubaneswar, india, 15−23. mindszenty, a., d’argenio, b. & aiello, g. (1996): lithospheric bulges at regional unconformities. the case of mesozoic-tertiary apulia.− tectonophysics, 252, 137−161. doi: 10.1016/0040-1951(95)00091-7 mindszenty, a. & d’argenio, b. (1994): carbonate platform emergence and bauxite formation.− aapg annual convention 06.12.−06.15.1994., denver, us, p. 217. muhs, d.r., budahn, j.r., prospero, j.m., skipp, g. & herwitz, s.r. (2012): soil genesis on the island of bermuda in the quaternary. the importance of african dust transport and deposition.− j. geoph. res., earth surface, 117, f3. doi: 10.1029/2012jf002366 parrish, j.t.,ziegler, a.m. & scotese, c.r. (1982): rainfall patterns and the distribution of coals and evaporites in the mesozoic and cenozoic.− palaeogeogr. palaeoclim. palaeoecol., 40, 67−101. doi: 10.1016/00310182(82)90085-2 parrish, j.t. (1998): interpreting pre-quaternary climate from the geological record. (perspectives in paleobiology and earth history series).− columbia university press, 338 p. patel-sorrentino, n., lucas,y., eyrolle, f. & melfi, a.j. (2007): fe, al and si species and organic matter leached off a ferrallitic and podzolic soil system from central amazonia.− geoderma, 137, 444−454. doi: 10.1016/j.geoderma.2006.10.002 piketh, s.j., tyson, p.d. & steffen, w. (2000): aeolian transport from southern africa and iron fertilization of marine biota in the south indian ocean.− south afr. journ. sci., 96/5, 244−246. posgay, k. (1967): a bauxit térfogatsúlya (the bulk density of bauxite).− bull. geol. soc. hung., 97/4, 414−422. poulton, s.w. & raiswell, r. (2002): the low-temperature geochemical cycle of iron: from continental fluxes to marine sediment deposition.− amer. journ. sci., 302/9, 774−805. doi: 10.2475/ajs.302.9.774 premoli-silva, i., erba,.e., salvini, g.,verga, d. & locatelli, c. (1999): biotic changes in cretaeous anoxic events.− journ. foraminiferal res., 29, 352−370. 87 mindszenty andrea: bauxites: feedbacks of system earth at greenhouse times price, g.d. & valdes, p.j., & sellwood, b.w. (1997a): quantitative palaeoclimate gcm validation: late jurassic and mid cretaceous case studies.− journ. geol. soc., 154, 767−772. doi: 10.1144/gsjgs.154.5.0769 price, g.d.,valdes, p.j. & sellwood, b.w. (1997b): prediction of modern bauxite occurrence: implications for climate reconstruction.− palaeogeograhy, palaeoclimatology, palaeoecology, 131, 1−13. doi: 10.1016/s0031-0182(96)00145-9 retallack, g.j. (2010): lateritization and bauxitization events.− econ. geol., 105, 655−667. doi: 10.2113/gsecongeo.105.3.655 ridgwell, a.j. (2002): dust in the earth system: the biogeochemical linking of land, air and sea philosophical transactions: mathematical, physical and engineering sciences 360/1801, december 2002, 2950−2924. doi: 10.1098/rsta.2002.1096 rijkenberg, m.j.a., fischer, a.c., kroon, j.j., gerringa, g.j.a., timmermans, k.r.,wolterbeek, h.t. & de baar, h.j.w. (2005): the influence of uv irradiation on the photoreduction of iron in the southern ocean.− mar. chem., 93, 119−129. doi: 10.1016/j. marchem.2004.03.021 schlanger, s.o. & jenkyns, h.c. (1976): cretaceous oceanic anoxic events, causes and consequences.− geol. mijnb., 55, 179−184. schlanger, s.o., arthur, m.a., jenkyns, h.c. & scholle, p.a. (1987): the cenomanian-turonian oceanic anoxic event, iu. stratography and distribution of organic carbon-rich beds and the marine δ13c excursion.− goel. soc. london, spec. publ. no 26, 371−399. sclater, j.g., hellinger, s. & tapscott, h. (1977): t/he paleobathymetry of the atlantic ocean from the jurassic to the present.− j. geol., 85, 509−552. doi: 10.1086/628336 scotese, c.r. (2001): atlas of earth history, vol.1. paleogeography.− paleomap project, arlington, texas, 52 p. scotese, c.r. (2002): http://www.scotese.com (paleomap website) sellwood, b.w. & price, g.d. (1993): sedimentary facies as indicators of mesozoic paleoclimate.− phil. trans. r. soc. london, b 341, 225−233. sherwood, s.c. & meyer, c.l. (2006): the general circulation and robust relative humidity.− journ. climate, 19, 6278−6290. doi: 10.1175/ jcli3979.1 singer, a. (1980): the paleoclimatic interpretation of clay minerals in soils and weathering profiles.− earth sci. rev., 15, 303−327. doi: 10.1016/00128252(80)90113-0 singer, a. (1984): the paleoclimatic interpretation of clay minerals in sediments – a review. earth sci. rev., 21, 251−293. doi: 10.1016/00128252(84)90055-2 tardy,y., n’kounkou, r. & probst, j-l. (1989): the global water cycle and continental erosion during phanerozoic time (570 my). amer. journ. sci., 289, 455−483. doi: 10.2475/ajs.289.4.455 tortell, p.d., maldonado, m.t., granger, j. & price, n.m. (1999): marine bacteria and biogeochemical cycling of iron in the oceans.− fems microbiology ecology, 29/1, 1−11. doi: 10.1111/j.1574-6941.1999.tb00593.x thiry, m. (2000): palaeoclimatic interpretation of clay minerals in marine deposits: an outlook from the continental origin.− earth sci. rev., 49, 201−221. doi: 10.1016/s0012-8252(99)00054-9 trenberth, k.e., smith, l., qian, t., dai, a. & fasullo, j. (2007): estimates of the global water budget and its annual cycle using observational and model data.− journ. hydrometeorology – spec.section (amer.meteor.soc.), 8, 758−769. doi: 10.1175/jhm600.1 velbel, m.a. (1993): temperature dependence of silicate weathering in nature: how strong a negative feedback on long-term accumulation of atmospheric co2 and global warming?− geology, 21, 1059−1062. doi: 10.1130/0091-7613(1993)021%3c1059:tdoswi%3e2.3.co;2 weissert, h. & mckenzie, j. (1979): cyclic anoxic events in the early cretaceous tethys ocean.− geology, 7, 147−151. doi: 10.1130/0091-7613(1979)7%3c147:caeite%3e2.0.co;2 volk, t. & hoeffert, m.i. (1985): ocean carbon pumps: analysis of relative strengths and efficiencies in ocean-driven atmoapheric co2changes.− in: sundquist, e.t. & broecker, w.s. (eds.): the carbon cycle and atmospheric co2: natural variations archean to present. geoph. monograph series, vol. 32, 99−100. doi: 10.1029/gm032p0099 ziegler, p.a. (1988): evolution of the arctic north atlantic and the western tethys. − aapg mem., 43, p. 198. 2019 | 72/2 | 109–128 | 21 figs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction since the early pioneering work of e.g. royden et al. (1983) and horváth (1984), the following thirty years or so have seen publication of a lot of papers concerning the origin and evolution of the pannonian basin (pb) and its marginal parts e.g. tari & pamić (1998); bada et al. (1999); horváth et al. (2006); dombrádi (2012); kovács et al. (2015); balázs et al. (2017 and references therein). generally, in these papers a very complex interdisciplinary and multidisciplinary approach has been applied. although, some of the authors didn’t have similar views to the general model of the pb and mechanisms of its genesis, longterm investigations led to greater understanding of these processes. today, the general structural pattern concerning the evolution of the pb is accepted (e.g. matenco & radivojević, 2012; balázs et al., 2016, 2017 and references therein). it is evident that the early to middle miocene preand syn-rift deposits of the pb show a transition from continental alluvial-lacustrine to fully marine environments (pavelić & kovačić, 1999; harzhauser & piller, 2007; harzhauser & mandic, 2008; magyar et al., 2013; sant et al., 2017). the peak of extensional tectonics was reached during the badenian–sarmatian rifting phase (ca. 16–12 ma) (e.g. fodor et al., 2005; radivojević et al., 2010; matenco & radivojević, 2012; radivojević & rundić, 2016). the long-lived lake pannon was formed at the middle/late miocene boundary (ca. 11.6 ma) as a consequence of the tectonic uplift of the carpathians that separated the basin from marine influences (magyar et al., 1999; ter borgh et al., 2013, 2015; sztanó et al., stratigraphic implications of the mio-pliocene geodynamics in the area of mt. avala: new evidence from torlak hill and beli potok (belgrade, serbia) ljupko rundić*, meri ganić, slobodan knežević, dejan radivojević and miloš radonjić university of belgrade, faculty of mining and geology, department of regional geology, kamenička 6, 11000 belgrade, serbia; (corresponding author: ljupko.rundic@rgf.bg.ac.rs) doi: 10.4154/gc.2019.11 abstract mt. avala is located on the southern margin of the pannonian basin (spb), a border zone between the uplifted morphostructures of the dinarides and carpathian-balkanides. similar to the pannonian basin, tectonostratigraphic evolution of the mt. avala area during the last 23 ma has is characterized by synand post-rifting processes as well as tectonic inversion. here, we present the results of field investigations of the miocene‒pliocene dynamics that led to different spatial positions of the same stratigraphic units (e.g. badenian and pannonian) in a relatively small area. these spatial relationships are interpreted in the context of pronounced block structures (torlak, beli potok and avala). torlak hill represents a horst structure with a core composed of mesozoic rocks and hillsides composed of the middle miocene sediments, which are present at the surface at altitudes up to 336 metres. nearby, there is the beli potok asymmetrical trough that was infilled by the late miocene sediments. the torlak horst and the beli potok trough structures are separated by the rakovica normal fault. in some places along the fault line, several geological units are vertically displaced more than a hundred metres. for example, in borehole kgk-14, the upper miocene pannonian marls are observed at a depth of 100 metres below the surface. however, only a few hundred metres away to the northeast, similar pannonian marls are observed at the surface, at an altitude of about 210 metres. due to the mentioned observed vertical movements along the block structures, a composite hilly relief with dominant the torlak hill and the beli potok valley was formed. 2015). seven million years later, lake pannon was filled with lacustrine and fluvio-deltaic sediments derived from the surrounding orogenic belts (e.g. magyar et al., 2013; radivojević & rundić, 2016). at the beginning of the pliocene, the “caspibrackish” giant lake pannon was reduced to the much smaller freshwater paludina lake (magyar et al., 1999; sztanó et al., 2015; mandic et al., 2015; rundić et al., 2016). a similar scenario was demonstrated from the southern margin of the pannonian basin (rundić et al., 2011, 2015, 2017). at the beginning of the miocene, the studied area was represented by continental-lacustrine facies of different ages (dolić, 1997, 1998; krstić et al., 2012; rundić et al., 2013, 2015). during the middle miocene (badenian), a maximum extension led to paratethys marine flooding in serbia as well as in other countries at the southern margin of the pb (e.g. ćorić et al., 2009; kovačić et al., 2011; pavelić & kovačić, 2018; sant et al., 2018). the late middle miocene to pliocene postrift thermal stage of subsidence was weak but more extensive than during the badenian (marović et al., 1995; 2002; 2007; radivojević & rundić, 2016). at the end of the miocene, mt. avala was an elongate island, with lake-margin and swamp environments formed along its shoreline. later, the pliocene– quaternary tectonic compression reactivated some older faults and the lake pannon sediments were differentially displaced and lost their lateral continuity (e.g. marović & knežević, 1985; knežević, 1989; marović et al., 1995; 2002; 2007; toljić et al., 2014). consequently, the system of uplifted block structures article history: manuscript received february 22, 2018 revised manuscript accepted february 28, 2019 available online june 3, 2019 keywords: mio-pliocene geodynamics, southern pannonian basin, avala and torlak horsts, beli potok trough, serbia g eo lo gi a c ro at ic a geologia croatica 72/2110 with lake pannonian deposits were exposed to erosion and weathering processes. in this study, the research objective was to provide more insights about the evolution of this relatively small-scale area (fig. 1). starting from the distribution of miocene sediments in the field, their exposure in the relief and an interesting relationship between the geological units (normal or tectonic boundaries, erosional contact, unconformity, spatial position of same units, etc.) we collected principal biostratigraphic, structural and geomorphologic evidence to show the distinct effects of mio-pliocene tectonics especially its stratigraphic implications. 2. geological settings the studied area is located on the southern margin of the pb, a border zone between the uplifted morphostructures of the dinarides and the carpathian-balkanides (marović & knežević, 1985; andjelković & andjelković 1996). according to the regional tectonic setting of serbia, the older mesozoic units in this area belong to the tethys oceanic domain, i.e. the vardar zone in the wider sense (dimitrijević, 1997; toljić, 2006, 2016) and the sava zone (schmid et al., 2008). the study area represents a region with complex geological features and is composed of various igneous and sedimentary rocks formed during the mesozoic, tertiary and quaternary periods (marović et al., 1995, 2002, 2007; toljić, 1996; 2006, 2016; ganić et al., 2011).the oldest rocks belong to jurassic carbonates, ophiolitic mélange, serpentinized peridotites, lower and upper cretaceous carbonates and upper cretaceous turbiditic and flysch deposits (toljić, 2016; toljić et al., 2018). during the oligocene, magmatic bodies forming dykes and sills of different thickness were intruded into these rocks (vasković & matović, 1996; toljić et al., 2018). all these rocks represent the basement rocks in the area. much later, different miocene and quaternary sedimentary units unconformably overlie jurassic serpentinites or cretaceous sediments (fig. 2). older miocene units (?lower miocene continental-lacustrine formation, predominantly) have a relatively narrow distribution figure 1. location (a) and geological sketch map (b) of the studied area (modified and upgraded after ivković et al., 1966 and toljić, 2016). numbers mark the studied outcrops and figure numbers in the text. key: to – torlak fault; rf – rakovica fault; tr – topčiderska reka fault; bp – beli potok fault; zr – zavojnička reka fault; zu – zuce fault, ka – kaludjerica fault. note: traces of the aforementioned faults are taken from marović et al. 2007). g eologia c roatica rundić et al.: stratigraphic implications of the mio-pliocene geodynamics in the area of mt. avala: new evidence from torlak hill and beli potok 111 (dolić, 1997; rundić et al., 2013). middle miocene marine and marine-brackish sediments are well developed and have been extensively studied (e.g. luković, 1922; stevanović, 1951; eremija, 1977a, 1987; petrović, 1995; knežević & šumar, 1994; rundić & knežević, 2017). similarly, the late miocene „caspibrackish“ sediments of the lake pannon were the subject of various stratigraphic studies beginning with the well-known studies by pavlović (1931) and stevanović (1951), followed by the biostratigraphic articles of krstić (1972, 1973, 1985), stevanović (1985, 1990), eremija (1989) and knežević (1989). 3. materials and methods most of the rock samples have been collected from both banks of the rakovica stream valley (rakovički potok) located in the n-nw part of mt. avala. other samples have been taken more toward the north-northeast of mt. avala (torlak, beli potok, leštane, and vrčin – fig. 1). all the analyzed samples were collected from the twelve outcrops and sections and two shallow boreholes (fig. 1). primarily, they were used for palaeontological and biostratigraphic analyses. fossil macrofauna (mostly molluscs) as well as their biostratigraphic position has been used for determining the different miocene units. after cleaning and preparation with water and hydrogen-peroxide, some of the specimens were subsequently examined under reflected light by olympus bh2 microscope. foraminifers and ostracods were photographed by leica binocular microscope. some key microfossils were photographed using sem (jeol jsm6610lv) at the department of mineralogy and petrology, faculty of mining and geology, university of belgrade. however, detailed analyses of these taxa are the subject of further investigations. bearing in mind that the area is covered by vegetation, the lack of structural information in previous research, as well as our own very poor data, the measurements of structural elements were not collected systematically (e.g. dip angle and dip direction, fault traces, geometric and kinematic properties, etc.). scarce individual measurements of bedding plane or fault trace were performed and used to support the above-mentioned stratigraphic results with structural and geomorphologic observations in the relief. the scarce data was supplemented with the dem terrain model and these interpretations were further connected to the previously published results. in that sense, some of ideas and conclusions could be described as provisional and are not based on real measurements in the field. furthermore, the basic geomorphologic data (gps coordinates and altitude, topographic map, google earth map, etc.) was used in order to pinpoint the main landforms and their possible relationships towards the main linear structures of relief. 4. results 4.1. the studied outcrops and sections 4.1.1. ?lower miocene (continental-lacustrine) bučvar clastites in the upper portion of the bučvar stream (bučvar potok), the left tributary of the zavojnička reka river, i.e. bolečica river, a figure 2. schematic geological column of the pre-neogene basement rocks and neogene-quaternary succession with palaeoenvironments and tectonic stages of the studied area (modified after ivković et al., 1966 and ganić et al. 2016). g eo lo gi a c ro at ic a geologia croatica 72/2112 thick package of clastic deposits called the bučvar clastites transgressively overlies serpentinites (n 44°45′04″, e 20°31′57″ – no.3 in fig. 1). herein, the medium-grained conglomerates consist of serpentinite clasts, quartzites, cherts, fragments of sand, pinkish to greenish sandstones and reddish clays which together build a heterogeneous series (fig.3b-d). macroscopically, they are barren of fossils. stevanović (1970) believed that these conglomerates represent a special stratigraphic horizon at the transition from the “helvetian to tortonian stage”, i.e. from the karpatian to the badenian stage. according to the same author, they are in tectonic contact with gray, badenian marine clays characterized by an abundant microand macrofauna. stevanović (1970) equated those conglomerates with the youngest member of the vrdnik series (fruška gora), i.e. the budafa conglomerates of mecsek mountain in southern hungary. a similar interpretation was proposed by eremija (1987). however, dolić (1997, 1998) is confident that the bučvar conglomerates belong to the youngest member of the slanci series (?lower miocene, egenburgian) and they represent the regressive phase and termination of the lacustrine environment in this area. more recent research has determined the presence of these clastites in the vicinity of torlak hill and in the upper part of the rakovica stream and its tributary (n 44°44′01″, e 20°30′20″ – fig.3a). according to dolić (1997, 1998) and rundić et al. (2013) these clastites represent the final phase of pre-badenian lacustrine sedimentation (fig. 3c, d). at the same time, in this study, a similar unit was observed in boreholes bt1-2 and bt1-3 near leštane. during exploratory drilling for the construction of the “bubanj potok” railway tunnel, it was observed that the bučvar conglomerate (more than 7 m thick succession) transgressively overlies the serpentinite (bt1-2). they consist of reddish, brown and dark green coarser conglomerates in alternation with fineto coarse-grained sandstones and lenses of greenish silty clay. in the field, this represents a distinct lithological succession that has a large spatial distribution and underlies the younger miocene rocks. unlike the overlying marine badenian gravel, conglomerates and sands, this unit does not contain fossils and has a different colour and petrological content (dolić, 1997, 1998; rundić et al., 2013). 4.1.2. the middle miocene (marine badenian) rakovica deposits the basal part of the badenian marine deposits is exposed along the upper part of the rakovica stream section and its right tributary (n 44°43′59″, e 20°30′10″ – no.4 in fig. 1). nearby, the lower portion of the stream, an outcrop of coarse-grained clastic rocks composed of gravels and poorly cemented polymictic conglomerates up to 1.2 m high has been studied (fig. 4a, b). the rakovica stream deposits are composed of well-rounded and subrounded fragments of quartzites and sandstones, moderately to well-sorted essentially in the form of coarse and very coarse gravel (pebbles). abundant platy and discoid clasts indicate an imbricated gravel (fig. 4c) succession. however, larger clasts (cobbles) of quartzites (up to 7 cm) are dominant (fig. 4d). besides the different rock clasts, a few indistinct remains of fossil shell imprints could be recognized (? solecurtus sp.). above these gravels and conglomerates, a 0.70 m thick yellow-brown sandstone with no visible fauna, and rare occurrences of small pebbles up to 1 cm diameter were observed. stratigraphically, these rocks mark the basal part of the badenian marine transgression in this area and transgressively overlie the previous reddish and varicoloured continental-lacustrine ?lower miocene sediments (dolić, 1997; rundić et al., 2013). figure 3. the continental-lacustrine ?lower miocene in the area of torlak hill: panoramic view of the bučvar stream towards the ne (a), a view inside the stream valley (b), a detail of reddish conglomerates, light-brown coarse-grained sandstones in intercalation with green silt and clay (c, d). g eologia c roatica rundić et al.: stratigraphic implications of the mio-pliocene geodynamics in the area of mt. avala: new evidence from torlak hill and beli potok 113 above the previous outcrop, a hundred metres downstream, close to the top of the left rakovica stream bank (fig. 5), there is a well-known badenian sand section (n 44°43′46″, e 20°30′15″ – no. 5 in fig. 1) up to 10 m high. the first data concerning the “mediterranean fauna” of the rakovica stream (rakovički potok) were described by pavlović (1890, 1893) and until recently, detailed studies about the marine badenian shallow-water “seashore” sand were published (e.g. ganić et al., 2016 and references therein). the section contains a very rich and diverse macroand microfauna including more than 70 species of gastropods and bivalves, abundant foraminifers and ostracods, echinoids, fish otoliths, etc. that confirm the marine flooding in this area. in this study, the microfaunal association of foraminifers and ostracods (ammonia beccarii linné, elphidium crispum (linné), borelis melo fichtel et moll, cletocythereis haidingeri (reuss), cnestocythere truncata (reuss), costa edwardsii (roemer) was discovered, which further addresses the depositional environment and paleoecological characteristics of the study area. the last recent detailed studies of fossil gastropods and otoliths confirm the shallow-water character of the aforementioned sands (schwarzhans et al., 2015; ganić et al., 2016). a few metres higher in the succession, the ?upper badenian leitha limestone (wiedl et al., 2012) was developed as another facies (n 44°43′44″, e 20°30′09″ – no.6 in fig. 1). it is represented by hard, poorly bedded and massive fossiliferous limestone, fractured and partly karstified at the top of the section. it appears in the form of large blocks in the relief (fig. 6). the limestone is determined to represent a biocalcarenite. fossil detritus is mainly composed of calcareous algae, molluscs, echinoids, bryozoans, and large benthic foraminifers. rare detritus comprises mainly quartz clasts together with carbonates, quartzites, schists, and cherts. clasts are well rounded and range from 0.4–1 cm in size. frequent bivalve remnants (glycymeris pilosus (linné), flabel­ lipecten besseri (andrzejowski) and ostrea sp. are present. gastropod (turritella sp., hydrobia sp., etc.), foraminifer (am­ phistegina sp., ammonia sp., borelis sp., textularia sp. and others), and bryozoan fragments have also been identified (ganić et al., 2016). bryozoans are represented by branching forms. according to rundić et al. (2013) the leitha limestone in the study area, due to the predominant fossil composition could be categorized as an algal-foraminifer-bryozoan type of limestone. 4.1.3. middle miocene (marine-brackish sarmatian) rakovica deposits along the rakovica stream valley, some two hundred metres further to the south, two new sarmatian sections were discovered in both stream banks. the first is observed on the left bank, near to the stream floor (n 44°43′38″, e 20°30′04″ – no.7 in fig. 1). an outcrop more than 5 m high and up to 20 m long exposes grey to brownish laminated sand and poorly cemented sandstone in alternation with gray to greenish silty marl (fig. 7a). the gentle dip angle of these sediments is variable and at the south end of the section reaches up to 13 degrees dipping towards the ne (fig. 7b). there is no visible macrofauna. based on the observed foraminifera and ostracod association, this section corresponds to the lower sarmatian deposits (elphidium cf. reginum d’orbigny, el. macellum (fichtel et moll), el. aculeatum d’orbigny, quinqueloculina sp., ammonia ex. gr. beccarii (linné), aurila notata (reuss), xestoleberis sp., etc.). the second outcrop, is observed in a new large section (n 44°43′45″, e 20°29′54″ – no.8 in fig. 1) located on the opposite side figure 4. the badenian basal conglomerates: small outcrops at the upper part of the rakovica stream valley (a, b), a close up of the relatively well-sorted, imbricated conglomerates (c), semi-rounded pebbles of the quartzites and sandstones (d). g eo lo gi a c ro at ic a geologia croatica 72/2114 figure 5. the upper badenian sands: a well-known badenian sand section in the upper part of the rakovica stream (a, b), persistrombus coronatus (defrance) (c) and, typical microfossil assemblage of the upper badenian (ammonia ex gr. beccarri linne, elphidium crispum (linne), borelis melo fichtel & moll, etc. (d). figure 6. the upper badenian poorly-bedded limestone (leitha limestone) at the upper part of the rakovica stream valley (a, b). figure 7. the lower sarmatian section of grey to brownish laminated sand and poorly cemented sandstone (a) in alternation with gray to greenish silty marl (b). g eologia c roatica rundić et al.: stratigraphic implications of the mio-pliocene geodynamics in the area of mt. avala: new evidence from torlak hill and beli potok 115 of the rakovica stream valley. it exposes a section more than 80 m long and up to 12 m high of the light brown to yellowish sands and poorly cemented parallel to cross-laminated sandstones intercalated with thin interlayers of gray marls and platy limestones (fig. 8a-c). stratigraphically and structurally, it overlies the previous described sarmatian section in fig. 7. on the westernsouthwestern part, a small lens of coarse-grained clastics and pebbles is interbedded in the lower part of the section. the mean dip angle of the sediments reaches 15 degrees (dip direction is 40°). this measured section contains relatively poor fossil association of molluscs, foraminifers and ostracods. most of the fossils are poorly preserved and their shells are covered or partly filled by fine-grained sediments and quartz grains. among them, the following mollusc species could be identified: ervilia dissita eichwald (fig. 8d), cerastoderma ex gr. vindobonensis (partsch in laskarev), ?calliostoma sp., cerithium sp., pirenella sp. the following foraminifers were determined: elphidium aculeatum (d’orbigny), el. macellum (fichtel et moll), anomali­ noides cf. dividens luczkowska, ammonia ex gr. beccarii (linné). elphidiums are common within the fossil assemblage and represent the most abundant specimens. among the ostracodes, only a few species were recognized: heterocythereis mehesi (zalanyi), aurila notata (reuss), loxocorniculina sp. biostratigraphically, all of the aforementioned species correspond to the lower sarmatian in age. 4.1.4. late miocene, lower pannonian (= pannonian sensu stevanović, 1985) rakovica marls at the rakovica stream valley near to the avala road, and just 200 m downstream of the sarmatian section mentioned above figure 8. the lower sarmatian: a large section of gray, silty marl in alternation with grey to brown laminated sandstones (a, b), thin interbeds of platy limestone and marls (c) ervilia dissita eichwald (d). figure 9. the lower pannonian sandy marl (a), sandy marls steeply dipping towards the southeast (b). g eo lo gi a c ro at ic a geologia croatica 72/2116 (fig. 7), an outcrop of the lower pannonian sandy marls, several metres in height and length, was discovered (n 44°43′33″, e 20°29′55″ – no.9 in fig. 1; fig. 9). rare fragments of fossil molluscs were observed (orygoceras sp., lymnocardium sp., melanopsis sp.). a relatively numerous ostracod association and scarce recrystallized forms of the sarmatian foraminifers indicates an age close to the sarmatian/pannonian boundary. also, the steep dip angle of the marls (73–75°) and a dip direction to southeast suggest the deformation is related to the proximity of the rakovica fault which is responsible for this tilting (figs. 9b and 21). among the ostracodes, genera such as cyprideis, amp­ locypris and candona predominate. the following species were identified: cyprideis kollmanni krstić, c. cf. heterostigma (reuss), hemicytheria cf. folliculosa (reuss), h. ampullata (mehes), candona (propontoniella) candeo krstić, amplocypris cf. firmus krstić, a. cf. recta (reuss), a. perphoratus krstić, herpetocyprella auriculata (reuss), cypria siboviki krstić, loxoconcha granifera (reuss), l. mülleri (mehes), l. porosa (mehes), l. cf. rhombovalis pokorny, candona (thaminocypris) improbus krstić, candona (typhlocypris) lunata (mehes), c. (t.) trigonella hejjas, leptocythere(amnicythere) miscere krstić, l. (a) cf. servica krstić, loxocorniculina hodonica pokorny, xestolebris sp. 4.1.5. late miocene, upper pannonian (= pontian sensu stevanović, 1985) beli potok clastic deposits along the road to the konopljište stream, in the beli potok village, a section up to 2 m high and more than 5 m long, formed of conglomerates, semiconsolidated sandstones, gravels and coarse-grained sand can be observed (n 44°42′31″, e 20°31′42″ – no.10 in fig. 1). in the lower part of the section, coarse-grained poorly cemented sandstones and sands are predominant (fig. 10a, lower part), containing scarce molluscs such as melanopsis figure 10. the lower pontian (sensu stevanović) clastics, predominantly coarse-grained gravel and semiconsolidated conglomerates (a, b), recrystallized shells of mytilopsis sp. (c, d) and, a partly destroyed specimen of m. trnskii (brusina) (e). g eologia c roatica rundić et al.: stratigraphic implications of the mio-pliocene geodynamics in the area of mt. avala: new evidence from torlak hill and beli potok 117 rugosa handmann (= m. wolfgangfisheri neubauer, harzhauser, kroh, georgopoulou & mandic, 2014). sporadically within the sand, pisoliths with the nucleus of fossil fragments can be observed. above these, poorly cemented conglomerates and gravels occur with a large number of molluscs (fig. 10a, b). pebbles are well rounded and poorly sorted, but there is an internal layering and the appearance of cross stratification. recrystallized shells of molluscs, mostly congerians is of the main characteristic of the section ((fig.10c-e). among the molluscs, the following species were recognized: mytilopsis ungulacaprae (münster), m. trnskii (brusina), m. balatonica (partsch), limnocardium banaticum fuchs, didacna chyzeri brusina, melanopsis defensa fuchs, m. rugosa handmann (= m. wolfgangfisheri neubauer, harzhauser, kroh, georgopoulou & mandic, 2014). biostratigraphically, the section belongs to the “lower pontian”, sensu stevanović i.e. it corresponds to the upper pannonian congeria praerhomboidea zone i.e. a time interval between 8–9 ma (magyar & geary, 2012). nevertheless, the aforementioned outcrop belongs to the littoral facies of lake pannon. “upper pontian” outcrops up to 10 m thick have been discovered along the ring road near mt. avala. generally, they consist of gray silts and sandy marls (n 44°43′11″, e 20°32′15″ – no.11 in fig. 1). however, they exhibit a yellow-brown colour on the surface (fig. 11a, b). the lower, older part of the section with a height of 4 m, is composed of brownish to gray, sandy marl (fig. 11c, d) which contains rare molluscs such as lymno­ cardium cf. mayeri (m. hörnes), l. riegeli (m. hörnes), mytilopsis croatica (brusina), m. zagrabiensis (brusina). above these mentioned marls, ~1.5m thick gray silts contain a similar fossil association (large candonids prevailing among the ostracods – fig. 11e). they are intercalated with gray sandy silts (up to 1m thick) and a thin interlayer of silts (10–20cm) with lymnocardium zagrabiense (brusina). besides molluscs, a very abundant ostracod assemblage was also observed: cypri­ deis triangulata krstić, hemicytheria josephinae (zalanyi), h. dubokensis krstić, bakunella dorsoarcuata (zalanyi), figure 11. the upper pontian (sensu stevanović) light-brown, fine-grained laminated sandy marls (a, b) and gray silts with large molluscan remains (c, d). detail of the ostracod assemblage (e). g eo lo gi a c ro at ic a geologia croatica 72/2118 camptocypria zalanyi krstić, camptocypria flectimarginata sokač, amplocypris bacevicae krstić, cypria tocorjescui hanganu, loxoconcha cumsacui krstić, l. schweyeri suzin, thaminocypris sp., camptocypria sp., serbiella sp., pontoniella sp., lineocypris sp., etc. (fig. 11e). all determined fossils (ostracods especially) indicate an early “upper pontian” (sensu stevanović) age. it is the last level in the section where the fossil remains were found. above this, there is a light yellow layer of sandy silt (up to 2 m thick), which contains carbonate concretions of different sizes. finally, the quaternary yellowish to brown proluvial-deluvial deposits up to 1m thick covers the section. 4.1.6. quaternary deposits in the studied area, the quaternary sediments have a relatively small thickness, up to 15 m. they are widespread over the older stratigraphic units. mostly, they cover the various miocene as well as the pre-neogene sediments (n 44°43ʹ44ʹ ,́ e 20°33ʹ27ʹʹ – no.12 in fig. 1; fig. 12). they include the pleistocene proluvial/deluvial coarse to medium-grained clastics, slope loess sequences and, sporadically, old landslides and colluvial products (leštane, torlak, resnik, and vrčin) up to 12 m thick. holocene deposits are represented by thin alluvial sediments cropping out along the zavojnička reka valley and prolluvialdelluvial and colluvial sediments. above the right bank of the upper part of the rakovica stream, near the road for mt. avala and close to the previously described new section of the sarmatian sediments (see fig. 8), steeply inclined clastics were discovered (n 44°43ʹ44ʹ ,́ e 20°29ʹ28ʹʹ – no.13 in fig. 1). they consist of breccias as well as conglomerates with clasts of cretaceous sediments, quartzites, dacito-andesites. rock boulders and cobbles are sub-rounded and poorly sorted a maximum diameter of <40 cm (fig. 13a, b). abundant reworked badenian and sarmatian fragments are included in these deposits (fig. 13c). since these clasts are found in the vicinity of the rakovica fault, it can be assumed that their genesis is related to the tectonic movements of structural blocks around the rakovica fault, which resulted in a denivelation of terrain, formation of steep slopes and predominant gravitational processes (e.g. proluvial processes) with deposition of clastic bodies. these clastics were probably generated during the early pannonian. 4.2. the subsurface data as an exception to the collected surface data from the aforementioned outcrops and sections, an additional two shallow boreholes (bt1-2 and bt1-3) have been analyzed (see fig. 1). they were drilled at the top of the hill near leštane, close to the e75 highway, for the purpose of a future railway tunnel “bubanj potok”. 4.2.1. borehole bt1-2 (n 44°43′10″, e 20°34′01″) a few different stratigraphic units were recognized within the 90 m of core log (fig. 14). at the base of the well (depth interval 38–90 m), more than 50 m of dark to greenish serpentinized peridotites and serpentinites were discovered. in the upper part, the serpentinites are tectonized and contain a lot of reticulate fractures. these fractures are infilled with magnesite. the serpentinites are overlain by a package of hard serpentinized breccias (at the depth interval 27–38 m) more than 10 m thick, which contain serpentinite fragments of different size, representing the transition zone towards the overlying miocene and quaternary cover. transgressively on the serpentinized breccias, variegated coarse-grained sands and conglomerates of the bučvar member (the slanci fm.) are up to 7 m thick and represent the continental-lacustrine cycle of the early miocene (dolić, 1997, figure 12. the contact between the blueish-gray serpentinites in the basal part of the section (1) and the pleistocene delluvial-prolluvial clastites (2) and slope loess sediments (3), and the holocene delluvial-prolluvial clastites (4) and recent soil at the top of the section (5). g eologia c roatica rundić et al.: stratigraphic implications of the mio-pliocene geodynamics in the area of mt. avala: new evidence from torlak hill and beli potok 119 1998). there are no fossils identified within this unit which represents the lateral continuation of the previously mentioned similar sediments from the bučvar and rakovica streams (see fig. 3). at the same time, at 20.2 m below the surface, the middle miocene badenian basal clastites (5.2 m thick) indicate the marine transgression which occurred in this area. they consist of different clasts of gravel, sandstones and carbonate rocks. sporadically, only fragments of mollusc shells could be visible. typical the leitha limestone with lot of molluscs (chlamys sp., glycymeris sp.) and corallinacean alga (lithotamnion sp.) was found at the depth interval of 6.5–15.0 m. at the top of the limestone, a thin crust of limestone decomposition is visible. finally, at the at the top of core, up to 6.5 m of poorly cemented loess-like sediments constitute the last stratigraphic unit. 4.2.2. borehole bt1-3 (n 44°43′19″, e 20°34′36″) the second borehole, drilled in the vicinity of bt1-2 (fig. 1), reached the ?lower miocene reddish series at a depth of 47 m (the bučvar member of slanci fm.; dolić, 1997, 1998 – see fig. 15). stratigraphically, these two wells can be easily compared in their uppermost 30 metres. herein, only three units were recognized and, practically it represents the upper portions of well figure 13. coarse-grained breccias and conglomerates with clasts of cretaceous sediments, quartzites, dacito-andesites (a, b) and redeposited material from the badenian and sarmatian deposits (c). g eo lo gi a c ro at ic a geologia croatica 72/2120 bt1-2. however, the middle part of the core log (depth interval 4–43 m) is represented by the marine badenian unit (basal clastites, gravel and sandstones and the leitha sandy limestone). many fossil remains confirm the badenian age (chlamys sp., os­ trea sp., conus sp., red algae, bryozoans, corallinacean algae (lithotamnion sp.), etc. at the top of the drilled succession, the uppermost portion (c.4 m), of thick deluvial yellowish silts, gray silty clays and loess sediments comprise the limestone cover. figure 14. lithostratigraphic log of borehole bt1-2, in the vicinity of leštane. figure 15. lithostratigraphic log of borehole bt1-3, in the vicinity of leštane. g eologia c roatica rundić et al.: stratigraphic implications of the mio-pliocene geodynamics in the area of mt. avala: new evidence from torlak hill and beli potok 121 4.3. geomorphology and some structural properties of the study area and its vicinity the lack of quality information i.e. a small number of measured structural elements (no systematic measurements of the direction of inclination of layers, stress analysis, etc.) as well as the morphological diversity of the area were the main reasons for geomorphologic consideration in order to try to identify the position of neotectonic active structures. we tried to support and possibly connect the afore-mentioned stratigraphic results with geomorphologic observations of the relief. in addition, these observations are connected with an estimation of the structural elements based on a dem terrain model and general (not systematic) analysis of linear relief structures. in other words, this approach was forced due to circumstances but, in our mind, useful. the wider study area occupies approximately 140 km2. morphologically, it can be divided into two parts: a composite hilly landscape consisting of the torlak hill (310 m) and mt. avala (511 m) and surrounding low hilly area (200–250 m) that are both dissected by the nnw–sse striking topčiderska reka and zavojnička reka valleys (fig. 16). these valleys represent the principal drainage systems of the study area. at the same time, torlak hill and mt. avala represent a drainage divide because the topčiderska reka water course flows to the sava river whereas the zavojnička reka runs to the danube river. at many locations, secondary e–ne directed streams have figure 16. the digital elevation model (dem) of the studied area with the positions of the two main drainage systems (topčiderska reka and zavojnička reka) as well as the topographic cross-sections with locations of the main faults (1–4). for the legend, see fig. 1. the original elevation data provided by japan aerospace exploration agency (jaxa). g eo lo gi a c ro at ic a geologia croatica 72/2122 asymmetric valleys with gently dipping northern sides and steeper southern slopes (fig. 16, profiles 1–4). in some places, the lower parts of the streams are covered by recently formed colluvial sediments from currently active slope gravitational movements, i.e., landslides and/or slope creeping processes (fig. 12, northeastern slope of torlak hill). these sliding processes suggest instability of the steep geologically conditioned slopes in the study area affected by either geological heterogeneity or exhumation along the recent inactive faults (marović et al., 2007; kovacs et al., 2015 and references therein). based on these relief data as well as the observed topčiderska reka and zavojnička reka river flows that are obviously structurally controlled (see figs. 1, 17 and 21), it is reasonable to argue that drainage system and landscape evolution during pontian-quaternary are conditioned by uplift of the torlak block which has already been elevated since the early upper miocene (fig. 1). uplift of the torlak block was probably controlled by the ne– sw striking torlak fault as well as the e–w directed rakovica fault and its segments (figs.17 and 21). this structure defines the northern edge of the beli potok trough which represents the area of subsidence filled by the upper miocene sediments (figs. 17 and 20). except for some individual measurement of faults and strata orientation within the different miocene units, the analysis of the fault systems was performed by the interpretation of digitally generated terrain of the wider area of mt. avala (fig. 17a) which is supported by the known facts (e.g. marović & knežević, 1985; toljić, 1996; marović et al., 2007). the main assumption was the tectonic control of the orientation of river valleys and linear features that were recognized at the given map scale. in addition to the authors rare measurements, the fault kinematics and timing in the wider area were taken from the aforementioned references. recognized structures were measured as line segments of given length (~ 2km) and plotted on a rose diagram (fig. 17b). the statistical interpretation of the linear features (orientation of river valleys, changes of slope angles, and sharp turns of water flows, etc.) as well as the main fault categories separated in the wider area of mt. avala (marović & knežević, 1985; marović et al., 2007) indicates the two main trends of the fault network. first, the (f1) fault system is generally oriented in a nw – se direction (fig. 17a, b). in the study area, the topčiderska reka (tr), zavojnička reka (zf) and kaludjerica (kf) faults belong to this system. later, from the post-sarmatian time, some of them were reactivated in the compressional regime and show a reverse character (figs. 1, 16, 18 and 21). this system is mainly inherited from the collisional processes that happened during late cretaceous and paleogene times (marović et al., 2007). this collision is classically interpreted as post jurassic obduction, large scale faulting and thrusting within the innermost units of the dinarides and with a general nw – se strike (along the central part of the balkan peninsula) (toljić et al., 2018). structures related to these events are best documented in the pre-neogene formations in the study area (toljić, 2016). during the later tectonic events these faults were reactivated (marović et al., 2007; see fig. 18). the younger, second fault system (f2) is related to the formation and later evolution of the pannonian basin. the (f2) faults system orientation reflects a general enewsw direction with a pronounced ne-sw direction (fig.17a, b). these events were controlled by extensional regimes and subsequent tectonic inversion (marović et al., 2007). in the study area, the rakovica (rf), beli potok (bp) and torlak (to) faults are recognized within this system. they are responsible for the dissection of the older faults from the f1 system (fig. 17a) and along these ene – wsw oriented faults the block structures with pronounced vertical movements were developed (figs. 20 and 21). besides this orientation, faults which were reactivated in the late miocene or neotectonic stage (see fig. 18), exhibit a direction figure 17. a) map of the orientation of linear structures in the broader study area. main faults and neotectonic units separated according to marović & knežević (1985), toljić (1996) and marović et al. (2007); b) rose diagram plotted from the map of linear structures. measurements of the orientation of fault traces were based on linear lengths of approximately 2 km. g eologia c roatica rundić et al.: stratigraphic implications of the mio-pliocene geodynamics in the area of mt. avala: new evidence from torlak hill and beli potok 123 similar to the f1 structure and they outline block structures in the studied area (figs. 1, 17, 21). in the study area, there is no measured fault that follows the late miocene post-rifting subsidence and pliocene compressional tectonics. however, a nice example is found in boždarevac (n 44°32ʹ27ʹ ,́ e 20°22ʹ41ʹʹ – fig. 17a), 20 km southwest of mt. avala where there is pinpointed movement along a fault which resulted in vertical displacement (up to 2.5 metres) of the sarmatian fossiliferous sands and limestones (fig. 18). this structure with a measured dip direction and dip angle of the fault (214/48) is part of the reverse faults which were reactivated in the ne-sw oriented compressional stress-field. faults of this direction are statistically recognized as linear structures that belong the first fault system (f1). furthermore, this structure corresponds to the similar nw-se orientation of the large fault structures observed in the study area such as the topčiderska reka and zavojnička reka faults (figs. 20 and 21). also, this system of structures is kinematically and spatially correlative with those previously recognized within the pannonian basin and its southern margins (e.g. bada et al. 2007; matenco & radivojević, 2012; toljić, 2016; toljić et al., 2018). 5. discussion and interpretation the mio-pliocene tectonic framework of the study area is controlled by the processes at the southern margin of the pannonian basin (matenco & radivojević, 2012; balázs et al., 2016; sant et al., 2018). as these processes are well documented in the central part of the basin based on subsurface data (horváth et al., 2015, matenco et al., 2016, balázs et al., 2017, etc.) they could be inferred for the area of mt. avala. new research findings collected in this study have shown that the oldest continental-lacustrine sediments (e.g. bučvar clastites) are present over larger areas than previously known (clastites are found in the vicinity of leštane and resnik, see fig. 19). in this study, however, there is insufficient information about the sedimentary conditions in which they were formed, especially since these deposits are most often destroyed by subsequent erosion processes (dolić, 1997). during the wellknown badenian marine transgression, a paratethys bay was established in the wider area north of today’s mt. avala which includes torlak, leštane and its vicinity (fig. 17). mt. avala represents a unique horst including the block of present day kosmaj mountain (marović & knežević, 1985). its significant differentiation begins in the early sarmatian when, following the faults of ne-sw and e-w directions, the subsidence and formation of smaller bays and troughs flooded by the waters of paratethys were carried out. such characteristics are reflected in the local structural units in the eastern section of the studied area, i.e., the ripanj, ralja and sopot bays; see fig. 17 (marović & knežević, 1985). in that sense, our findings of new sarmatian sections and outcrops in the area of the rakovica stream valley are important to support analogous scenarios in the northwestern part of the study area. the beli potok trough is similar, which subsided later in the late pannonian and figure 18. the reverse fault within the sarmatian sediments as a consequence of late miocene-pliocene compressional tectonics (village boždarevac, southwest of mt. avala). figure 19. comparative lithostratigraphic columns of the boreholes around mt. avala. the data concerning the kgk boreholes are taken from knežević (1989, 1990). for the location of boreholes, see fig. 1. g eo lo gi a c ro at ic a geologia croatica 72/2124 figure 20. the generalized geological cross-section through the beli potok trough (modified and upgraded after stevanović, 1951). numbers indicate the studied outcrops that are located near the profile line. for the faults key, see fig. 1. note: scale is adapted to better illustrate the geological relationships. pontian (sensu stevanović) (figs. 17, 20). it was a consequence of the uplifted blocks located in the southwestern parts of the velika morava trough (marović & knežević, 1985; djoković & marović, 1990; marović et al., 2007 – see fig. 17). later, during the pontian, the beli potok trough was reduced and directed to the east, towards the grocka-smederevo area (marović & knežević, 1985; see fig. 17). from a geodynamic point of view, the beli potok trough is an interesting structure because within the avala structural unit there are differential movements of the faults separating the local blocks. in the previous studies (e.g. laskarev, 1931) the existence of a large linear structure, the so-called the rakovica fault was noticed which locally separates the torlak horst from the trough, which stevanović (1951) distinguishes as the beli potok trough (fig. 20). the beli potok trough (224 m a.s.l.) situated between mt. avala (511 m a.s.l.) and torlak hill (310 m a.s.l.) is a local tectonic structure filled with upper miocene sediments. according to stevanović (1951) and eremija (1977b), it is an asymmetric trough in which neogene deposits are slightly folded in a shallow syncline. along mt. avala itself, the sediments of the lower pontian discordantly overlie the mesozoic palaeorelief (fig. 20). in contrast, in the northern part, at the base of torlak hill, there are pannonian marls underlying the pontian deposits. the torlak hill (horst) is composed of cretaceous and middle miocene badenian and sarmatian sediments. our research has generally confirmed the view of the aforementioned authors, but new insights have emerged on the nature and characteristics of the beli potok trough. namely, on the left bank of the rakovica stream near the avala road, the transitional section between the slightly dipping sarmatian laminated marls and fine-grained sand and the lower pannonian steeply inclined sandy marls was discovered (fig. 20). some 300 m further to east (210 m.a.s.l.), the younger pannonian marls with well-known congeria czjzeki were discovered. these new findings confirm the previous investigations and indicate more than a hundred metres of vertical movement of the blocks in this area (e.g. marović & knežević, 1985). furthermore, these new findings are corroborated with the previously studied borehole kgk-14 (190.8 m a.s.l.) downstream from the rakovica fault line (fig.19). the drilling was carried out within the beli potok trough in which sediments of the upper and lower pontian (sensu stevanović) were determined down to a depth of 105 m and the upper pannonian in the lower portion of the drilled succession, at a depth of about 155 m (knežević, 1989 – see fig. 19). besides, it was discovered that similar pontian sediments were deposited over the palaeorelief of jurassic and cretaceous rocks in the area of pinosava, e.g. borehole kgk-15 (fig. 19). at borehole kgk-13 near resnik (187 m a.s.l) these pontian sediments overlie the pannonian marl, sarmatian limestone and the bučvar clastites of the ?lower miocene (fig. 19). the vertical displacement of the aforementioned sediments along the rakovica fault is more than 100 m. in addition, this movement was determined based on comparison of the absolute altitude of the layers of the upper pannonian marls on the surface and the marls of the same age in borehole kgk-14 (the difference is more than 110m – knežević, 1989; fig. 19). the collected data within this work have confirmed that the formation of the rakovica fault is related to the early pannonian and that sedimentation in the beli potok trough occurred between the late pannonian to the late “pontian” (sensu stevanović). palaeogeographically, during the late miocene, in the beli potok area there was a lake pannon bay which was connected to the northern one in the grocka-smederevo area (marović & knežević, 1985; marović et al., 2007). during the pliocene and quaternary, the southern margin of the pb and the peri-pannonian realm (the present day šumadija part of serbia) experienced a continental phase of development (marović et al., 2007; sušić et al., 2015). the contemporary spatial position and absolute altitude of the miocene deposits in the elevated and subsided blocks can be taken as evidence of the tectonic activity in the wider part of mt. avala. on torlak hill the badenian sediments are located at altitudes above 300m. rocks of the same age were drilled in the grocka depression (the local peripheral structure of the velika morava trough) at depths between 1000 and 1100 m, i.e. between 900 and 1000 m absolute altitude (knežević et al., 1994). this means that in the study area the significant vertical movements began in post-badenian time (the post-rift phase) which continued to the mio-pliocene boundary (marović & knežević, 1985; marović et al., 2007). due to differential rock uplift in the vicinity of the beli g eologia c roatica rundić et al.: stratigraphic implications of the mio-pliocene geodynamics in the area of mt. avala: new evidence from torlak hill and beli potok 125 potok trough, late miocene sediments located at higher altitudes were destroyed by erosion. the younger and softer sediments, less resistant to abrasion, were eroded (see fig. 12). as a consequence, the youngest neogene deposits created during the late pannonian (the latest miocene, pontian sensu stevanović) were preserved only at the peaks of the lower hills (knežević, 1990; borehole kgk-16, fig. 19). ongoing rock uplift is documented at the peaks around the zavojnička reka valley and leštane, where the mesozoic ultramafites were discovered (e.g. leštane and its vicinity – unpublished data). this is confirmed within this study, in the analyzed boreholes bt1-2 and bt1-3 where the bučvar clastites and the leitha limestone cover the serpentinites. based on these observations, it can be assumed that a significant part of the studied area was covered by different miocene and pliocene sediments. the neotectonic map of the study area constructed in this work comprises several blocks with different kinematics from the miocene to the present (fig. 21). the most prominent topographic feature of the studied area is the avala. the avala block is defined by the topčiderska reka (tr), beli potok (bp) and zuce faults (zu). the presence of the late miocene sediments on the mountain slopes suggests that this structural unit was uplifted during sarmatian times. this is based on the fact that the youngest sediments on the slopes of mt. avala are “pontian” clastics which directly overlie the mesozoic rocks (fig. 20). during the early middle miocene, together with the torlak block, it represents a horst structure that extended southwards to mt. kosmaj (marović et al., 2007). the torlak block, which is situated north of mt. avala, is covered with pre-badenian and badenian sediments at about 300m a.s.l. it indicates the upward relative movements of the block that started at the end of the sarmatian and continues to recent times (e.g. in a few boreholes near leštane) (marović & knežević, 1985; rundić et al., 2015, 2017). the presence of the pre-badenian clastics in a few boreholes in the area of resnik at depths below 100 m (the westernmost part of the beli potok trough) where they overlie the mesozoic rocks support this fact (e.g. knežević, 1989). the block is formed by movements along the rakovica fault system (rf) and the torlak fault (fig. 20). in respect of the geomorphologic properties of the unusual flow/geometry of the zavojnička reka near the torlak block, we don’t have documented data. but, based on some observations by marović & knežević (1985) and djoković & marović (1990), it could be potentially associated with rather fast uplift of the torlak block from the pliocene to recent time. according to djoković & marović (1990) and toljić (2006, 2016) and the documented structural measurements of different mesozoic units in the study area, the zavojnička reka is controlled by the local fault system with its n-nw to s-se direction. after the “pontian” cycle of sedimentation (late pannonian, latest miofigure 21. neotectonic sketch map of mt. avala and the surrounding area (modified after djoković & marović (1990), toljić (1996) and marović et al. (2007). abbreviations: rf – rakovica fault, bp – beli potok fault, tr – topčiderska reka fault, zr – zavojnička reka fault, to – torlak fault, ka – kaludjerica fault and zu – zuce fault. note: traces of the faults are taken from the mentioned references. topography was generated from data provided by the japanese aerospace exploration agency (jaxa). g eo lo gi a c ro at ic a geologia croatica 72/2126 cene) between the avala and torlak structural blocks, the fluvial phase of relief formation began (marović & knežević, 1985). during that time, as the uplift of torlak hill progressed, the zavojnička reka changes its flow from se-nw and turns towards the e-ne, away from torlak. this activity led to the formation of the new, local structure along which the new flow was established (fig. 21). the beli potok trough is situated between these two relatively uplifted blocks. it is formed by the rakovica and beli potok faults. morphologically it comprises several valleys of creeks flowing towards zavojnička and the topčiderska reka. superposition of the neogene formations within the trough and the neighbouring blocks indicates that the subsidence started late in pannonian time. this trough is kinematically and spatially correlative with similar structures observed south of fruška gora mt. (e.g. sava half-graben) (matenco & radivojević, 2012). unfortunately, there is no seismic section within the studied area that can further support these interpretations. from the structural point of view and according to the tectonic settings of šumadija and part of nw serbia, the area of the torlak hills and mt. avala belongs to the avala-orešac structural unit characterized by blocky structure (marović & knežević, 1985; marović et al., 2007). according to marović & knežević (1985), toljić (1996, 2016) and marović et al. (2007), the avala-orešac structural unit was dissected into smaller blocks by systems of ne-sw (partially e-w) striking mio-pliocene faults (or remobiled the older ones). the avala horst as the largest structure in the aforementioned zone extends from the sava and the danube rivers in the north to the sopot and stojnik in the south (marović & knežević, 1985; marović et al., 2007). the avala horst is oriented almost meridionally, and it is constrained on all sides by extensional faults related to the syn-rift phase of which the most striking are those towards the velika morava trough (marović et al., 2007, see figs. 17 and 21). it was built mostly from pre-neogene, jurassic–cretaceous sediments (sometimes broken up by upper cretaceous and tertiary volcanites), in the eastern belt of ultramafites (serpentinite, peridotite and dunites), and on the edge of miocene deposits. all through the neogene, the avala horst shows different activity. in the early miocene, it represented the unified horst structure including the torlak and kosmaj highs. it was an area of denudation, but in some parts, e.g. in the marginal horst zones and its local troughs–bays, deposition took place. during the late middle miocene (sarmatian) the avala horst separated from the torlak horst by an e-ne to w-sw fault system and their uplift started as individual blocks. generally, this trend of uplift has continued to recent time (marović et al., 2007). 6. conclusions based on all the obtained results as well as their interpretation, the following conclusions concerning the mio-pliocene geo dynamics and its consequences can be drawn. in the studied area of mt. avala, the torlak horst and beli potok trough are the most important geological block structures. they exhibit significant vertical displacements along the rakovica fault of up to 200m. for example, in the borehole kgk-14, below the “pontian” deposits there are pannonian marls at absolute altitudes below 100 metres. however, only a few hundred metres away towards the northeast, at the foot of torlak hill, the same pannonian marls are found at the surface at an altitude of about 210 metres. at the same time, at the top of torlak hill, badenian sediments are present on the surface at an altitude of around 336 metres. they documented a well-known paratethys marine transgression as one of the most important geological events during the middle miocene. the field observations have confirmed that the rakovica fault was tectonically active within the pannonian and that the sedimentation in the beli potok trough occurred between the late pannonian to the “late pontian” (sensu stevanović). besides, the occurrence of the large clastites and boulders near the rakovica fault is related to their formation during the late miocene and pliocene (and probably in the early pleistocene). as a result of vertical tectonic movements along the block structures, a complex hilly relief with torlak hill and a valley in the area of the beli potok was formed. acknowledgment the authors wish to thank the ministry of education and science, republic of serbia for supporting this study (project no. 176015). we express thanks to prof. m. toljić (belgrade university) for the helpful discussion regarding the structural features of the research area. special gratitude goes to the reviewers for their constructive comments and suggestions that greatly improved an earlier version of the manuscript. references andjelković, m. & andjelković, j. (1996): tektonsko – paleogeografsko – stratigrafski ciklusi u tercijaru srbije [tertiary tectonic­palaeogeographic­strati­ graphic cycles of serbia ‒ in serbian and english].– ann. geol. pennins. balk., 60/1, 1–21. bada, g., horvath, f., gerner, p. & fejes, i. (1999): review of the present-day geodynamics of the pannonian basin: progress and problems.‒ journal of geodynamics, 27, 501–527. doi: 10.1016/s0264-3707(98)00013-1 bada, g., horváth, f., dövényi, p., szafián, p., windhoffer, g. & cloetingh, s. (2007): present-day stress field and tectonic inversion in the pannonian basin.‒ global and planetary change, 58, 165–180. doi: 10.1016/j.gloplacha.2007.01.007 balázs, a., matenco, l., magyar, i., horváth, f. & cloetingh, s. (2016): the link between tectonics and sedimentation in back-arc basins: new genetic constraints from the analysis of the pannonian basin.‒ tectonics, 35, 1526–1559. doi: 10.1002/2015tc004109 balázs, a., burov, e., matenco, l., vogt, k., francois, t. & cloetingh, s. (2017): symmetry during the synand post-rift evolution of extensional back-arc basins: the role of inherited orogenic structures.‒ earth planet. sci. lett., 462, 86–98. doi: 10.1016/j.epsl.2017.01.015 ćorić, s., pavelić, d., rogl, f., mandic, o., vrabac, s., avanić, r., jerković, l. & vranjković, a. (2009): revised middle miocene datum for initial marine flooding of north croatian basins (pannonian basin system, central paratethys).‒ geologia croatica, 62/1, 31‒43. doi: 10.4154/gc.2009.03 dimitrijević, m.d. (1997): geology of yugoslavia, 2nd edition.‒ geoinstitute, belgrade, 250 p. djoković, i. & marović, m. (1990): rupturni sklop šireg područja avale i ljute strane (severna šumadija). [rupture setting of the broader area of the avala and ljuta strana (northern šumadija) – in serbian].– xii congress of geologists of yugoslavia, ohrid, vol. 5, 46–54. dolić, d. (1997): jezerski miocen kod beograda [lake miocene near belgrade ‒ in serbian and english].– ann. geol. pennins. balk., 61/2, 15–49. dolić, d. (1998): the relationship of paratethyan and miocene lake deposits of serbia. proceedings of xiii congress of geologists of yugoslavia, v. 2, p. 373–382. dombrádi, e. (2012): deformation of the pannonian lithosphere and related tectonic topography: a depth-to-surface analysis.‒ utrecht studies in earth sciences, 19, 1–176. eremija, m. (1977a): miocen u oblasti ekshumiranog mezozojsko-serpentinskog paleoreljefa, od rakovice do ripnja [miocene in the exhumed mesozoic­serpentine area of palaeorelief, from rakovica to ripanj – in serbian].– in: petković, k. (eds.): géologie de le serbie. stratigraphie, ii/3, 145–154. eremija, m. (1977b): pliocen belopotočke rov-sinklinale [pliocene of the beli potok trench­syncline – in serbian].– in: petković, k. (eds.): géologie de le serbie. stratigraphie, ii/3, 178–181. eremija, m. (1987): badenski kat [badenian – in serbian].– in: anđelković, m. (eds.): la géologie des environs de belgrade i, géologie et géodinamique, 151–172. g eologia c roatica rundić et al.: stratigraphic implications of the mio-pliocene geodynamics in the area of mt. avala: new evidence from torlak hill and beli potok 127 eremija, m. (1989): panonski kat [pannonian – in serbian, with an english summary].– in: anđelković, m. (eds.): geology of the general belgrade area. vol.iv, paleogeography. university of belgrade, belgrade, 244–259. fodor, l., bada, g., csillag, g., horváth, e., ruszkiczay-rüdiger, z., palotás, k., síkhegyi, f., timár, g., cloetingh, s. & horváth, f. (2005): an outline of neotectonic structures and morphotectonics of the western and central pannonian basin.‒ tectonophysics, 410, 15–41. doi: 10.1016/j.tecto.2005.06.008 ganić, m., knežević, s., rundić, lj., milutinović, a. & ganić, a. (2011): neogene geodynamics in the light of 3-d visualisation – an example along the sava river (belgrade).‒ in: banjac, n. (eds.): 17. maegs, book of proceed., 157–158. ganić, m., radović, p., rundić, lj., bradić, k. & knežević, s. (2016): traces of drilling predation in the upper badenian (middle miocene) molluscs from the rakovica stream (belgrade).‒ geologia croatica, 69/2, 173–180. doi: 10.4154/gc.2016.14 harzhauser, m. & piller, w.e. (2007): benchmark data of a changing sea – palaeogeography, palaeobiogeography and events in the central paratethys during the miocene.‒ palaeogeogr. palaeoclimatol. palaeoecol. 253, 8–31. doi: 10.1016/j.palaeo.2007.03.031 harzhauser, m. & mandic, o. (2008): neogene lake systems of central and south-eastern europe: faunal diversity, gradients and interrelations.‒ palaeogeogr. palaeoclimatol. palaeoecol., 260, 417–434. doi: 10.1016/j.palaeo.2007.12.013 horváth, f. (1984): neotectonics of the pannonian basin and the surrounding mountain belts: alps, carpathians and dinarides.‒ annal. geophys., 2, 147–154. horváth, f., bada, g., szafián, p., tari, g., ádám, a. & cloetingh, s. (2006): formation and deformation of the pannonian basin: constraints from observational data.– in: gee, d.g. & stephenson, r. (eds.): european lithosphere dynamics, geological society london memoir, 32, 191–206. doi: 10.1144/ gsl.mem.2006.032.01.11 horváth, f., musitz, b., balázs, a., végh, a., uhrin, a., nádor, a., koroknai, b., pap, n., tóth, t. & wórum, g. (2015): evolution of the pannonian basin and its geothermal resources.‒ geothermics, 53, 328–352. doi: 10.1016/j.geothermics.2014.07.009 ivković, a., vuković, a., nikolic, j., kovačević, d., palavestrić, lj., petrović, lj., jovanović, o., trifunović, i. & sebinović, lj. (1966): osnovna geološka karta sfrj 1:100000, list pančevo l34–114 [basic geological map of sfry 1:100000, pančevo sheet – in serbian].– geološki zavod, beograd, savezni geološki zavod, beograd. knežević, s. (1989): prinove iz ponta belopotočkog rova [new specimens from the pontian of beli potok trough – in serbian, with an english summary].– ann. geol. pennins. balk., 53, 373–384. knežević, s. (1990): prilog poznavanju neogenih sedimenata okoline beograda (stratigrafski prikaz bušotine kgk-16 kod vrčina [a contribution to the study of neogene sediments in beograd area (stratigraphic column of hole kgk-16 at vrčin) – in serbian, with an english summary].– ann. geol. pennins. balk., 54, 373–384. knežević, s. & šumar, m. (1994): prilog poznavanju geologije grada beograda [a contribution to the study of belgrade local geology – in serbian, with an english summary].– ann. geol. pennins. balk., 58/2, 73–81. knežević, s., spajić, o., pavlović, m., ercegovac, m. & petrović, m. (1994): stratigrafska proucavanja tercijarnih naslaga u busotini g-1 u grockoj [stratigraphy of tertiary deposits in hole g­1 at grocka – in serbian, with an english summary].– ann. geol. pennins. balk., 58/2, 39–49. kovács, g., fodor, l., kövér, s., molnár, g., raáb, d., telbisz, t. & timár, g. (2015): verification of late miocene to quaternary structural control on landforms: a case study with comprehensive methodology from a low hilly area (western pannonian basin).‒ austrian journal of earth sciences, 108/2, 82–104. doi: 10.17738/ajes.2015.0015 kovačić, m., horvat, m., pikija, m. & slovenec, da. (2011): composition and provenance of neogene sedimentary rocks of dilj gora mt. (south pannonian basin, croatia).‒ geologia croatica, 64/2, 121–132. doi: 10.4154/gc.2011.10 krstić, n. (1972): genus candona (ostracoda) from congeria beds of southern pannonian basin.‒ monographs, vol. cdl, 39, sanu, belgrade, 1–146. krstić, n. (1973): biostratigraphy of the congerian beds in the belgrade region on the basis of ostracoda.‒ monographs, vol. 4, inst. geol. min. expl. investig. nuclear miner. raw mater., belgrade, 1–158. krstić, n. (1985): ostracoden im pannonien der umbegung von belgrad.– in: papp, a. et al. (eds.): chronostratigraphie und neostratotypen, miozän m6, pannonien. akadémiai kiadó, 103–143. krstić, n., savić, lj. & jovanović, g. (2012): the neogene lakes on the balkan land.– ann. geol. pennins. balk., 73, 37–60. doi: 10.2298/gabp1273037k laskarev, v., petković, v. & luković, m. (1931): geološka karta okoline beograda, 1: 25,000 [geological map of the belgrade vicinity ‒ in serbian].– geol. inst. kralj. jugoslav., beograd. luković, m. (1922): facije drugog mediteranskog kata u okolini beograda [second mediterranean facies from the belgrade surroundings – in serbian].– ann. geol. pennins. balk., 7/1, 22–41. magyar, i. & geary, d.h. (2012): biostratigraphy in a late neogene caspian-type lacustrine basin: lake pannon, hungary.– aapg memoir, 95, 1–10. magyar, i., geary, d.h. & müller, p. (1999): palaeogeographic evolution of the late miocene lake pannon in central europe.– palaeogeogr. palaeoclimatol. palaeoecol, 147, 151–167. magyar, i., radivojević, d., sztano, o., synak, r., ujszaszi, k. & pocsik, m. (2013): progradation of the paleo-danube shelf margin across the pannonian basin during the late miocene and early pliocene.‒ global and planetary change, 103, 168–173. doi: 10.1016/j.gloplacha.2012.06.007 mandic, o., kurečić, t., neubauer, t. & harzhauser, m. (2015): stratigraphic and paleogeographic significance of lacustrine molluscs from the pliocene viviparus beds in central croatia.‒ geologia croatica, 68/3, 179‒207. doi: 10.4154/gc.2015.15 marović, m. & knežević, s. (1985): neotektonika jednog dela šumadije i severozapadne šumadije [neotectonics of a part of šumadija and northwestern serbia – in serbian, with an english summary].– ann. geol. pennins. balk., 49, 221–247. marović, m., djoković, i., knežević, s., rundić, lj., mitrović, s., šumar, m. & toljić, m. (1995): principal geodynamic stages and paleogeographic changes in southeastern peripannonian realm of neogene and quaternary.‒ proc. xv congress c.b.g.a., geol. soc. greece, athens, sp. publ., 4/1, 69‒73. marović, m., djoković, i., pešić, l., radovanović, s., toljić, m. & gerzina, n. (2002): neotectonics and seismicity of the southern margin of the pannonian basin in serbia.‒ egu special publication, 277–295. doi: 10.5194/ smsps-3-277-2002 marović, m., toljić, m., rundić, lj & milivojević, j. (2007): neoalpine tectonics of serbia.‒ ser. monographs, serbian geological society, belgrade, 87 p. matenco, l. & radivojević, d. (2012): on the formation and evolution of the pannonian basin: constraints derived from the structure of the junction area between the carpathians and dinarides.‒ tectonics, 31, tc6007, 18–49. doi: 10.1029/2012tc003206 matenco, l., munteanu, i., ter borgh, m., stanica, a., tilita, m., lericolais, g., dinu, c. & oaie, g. (2016): the interplay between tectonics, sediment dynamics and gateways evolution in the danube system from the pannonian basin to the western black sea.‒ sci. total environ., 543, 807–827. doi: 10.1016/j.scitotenv.2015.10.081. neubauer, t., harzhauser, m., kroh, a., georgopoulou, e. & mandic, o. (2014): replacement names and nomenclatural comments for problematic species-group names in europe’s neogene freshwater gastropoda. part 2.‒ zookeys, 429, 13‒46. doi: 10.3897/zookeys.429.7420 pavelić, d. & kovačić, m. (1999): lower miocene alluvial deposits of the požeška mt. (pannonian basin, northern croatia): cycles, megacycles and tectonic implications.‒ geologia croatica, 52/1, 67‒76. pavelić, d. & kovačić, m. (2018): sedimentology and stratigraphy of the neogene rift-type north croatian basin (pannonian basin system, croatia).‒ a review, marine and petroleum geology, 91, 455–469. doi: 10.1016/j.marp pavlović, p.s. (1890): mediteranska fauna u rakovici [mediterranean fauna of rako­ vica – in serbian].– ann. geol. pennins. balk., 2, 9–60. pavlović, p.s. (1893): prinove geološkog zavoda [noveltis from geological survey – in serbian].– ann. geol. pennins. balk., 5/1, 212–223. pavlović, p. (1931): prilozi poznavanju tercijara u srbiji (pontiska fauna iz obala potoka konopljište [contributions to the knowledge of tertiary in serbia (pontian fauna from the banks of the konopljište stream) – in serbian].– ann. geol. pennins. balk., 10/2, 104–113. petrović, m. (1995): novi prilog poznavanju zona ammonia beccarii i prosononion granosum beograda [a contribution to the study of ammonia beccarii and prosononion granosum zones in belgrade – in serbian, with an english summary].– ann. geol. pennins. balk., 59/2, 61–68. radivojević, d., rundić, lј. & knežević, s. (2010): geology of the čoka structure in northern banat (central paratethys, serbia).‒ geologica carpathica, 61/4, 341‒352. radivojević, d. & rundić, lj. (2016): synrift and postrift miocene sediments of northern banat, serbia [sinriftni i postriftni miocenski sedimenti severnog banata u srbiji ‒ in english with serbian abstract].‒ underground mining, 28, 39‒60. royden, l., horváth, f. & rumpler, j. (1983): evolution of the pannonian basin system. 1. tectonics.‒ tectonics, 2, 63‒90. doi: 10.1029/tc002i001p00063 rundić, lj. & knežević, s. (2017): the miocene fossiliferous sites of the avala mt. (belgrade area, serbia) and their importance.‒ bulletin of the natural history museum, 10, 29‒41. doi: 10.5937/bnhmb1710029r rundić, lj., ganić, m., knežević, s. & soliman, a. (2011): upper miocene pannonian sediments from belgrade (serbia): new evidence and paleoenvironmental g eo lo gi a c ro at ic a geologia croatica 72/2128 considerations.‒ geologica carpathica, 62/3, 267‒278. doi: 10.2478/v10096-0110021-z rundić, lj., knežević, s. & rakijaš, m. (2013): badenian marine transgression: new evidence from the vrdnik coal basin (northern serbia) [srednje miocenska badenska transgresija: novi dokazi sa prostora vrdničkog ugljenog basena (fruška gora, severna srbija) ‒ in english with an serbian summary].‒ ann. geol. pennins. balk., 74, 9–23. rundić, lj., knežević, s., ganić, m. & bradić, k. (2015): novi podaci o stratigrafiji i tektonici rakovičkog potoka (miocen okoline beograda). [new data on stratigraphy and tectonics of the rakovica stream, miocene of the belgrade vicinity – in serbian and english].‒ in: skopljak, f. (eds.): 1st congress of geologists of bosnia & herzegovina, tuzla october 21–23, 2015, book of abstracts, 48–49. rundić, lj., vasić, n., životić, d., bechtel, a., knežević, s. & cvetkov, v. (2016): the pliocene paludina lake of pannonian basin: new evidence from northern serbia.‒ annales societatis geologorum poloniae, 86/2, 185–209. doi: 10.14241/asgp.2016.003 rundić, lj., ganić, m., knežević, s. & radivojević, d. (2017): mio-pliocene geodynamics and its stratigraphic consequences in the area of avala mt. (belgrade, serbia).‒ in: horvat, m. & wacha, l. (eds.): 7th intern. workshop on neogene of central and se europe, abstracts book, velika, croatia, 57‒58. sant, k., palcu, d., mandic, o. & krijgsman, w. (2017): changing seas in the early–middle miocene of central europe: a mediterranean approach to paratethyan stratigraphy.‒ terra nova, 29, 273–281. doi: 10.1111/ter.12273 sant, k., mandic, o., rundić, lj., kuiper, k. & krijgsman, w. (2018): age and evolution of the serbian lake system: integrated results from middle miocene lake popovac.‒ newsletter on stratigraphy, 51/1, 117–143. doi: 10.1127/ nos/2016/0360 schmid, s., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpinecarpathian-dinaridic orogenic system: correlation and evolution of tectonic units.‒ swiss journal of geosciences, 101, 139–183. doi: 10.1007/s00015-008-1247-3 schwarzhans, w., bradić, k. & rundić, lj. (2015): fish-otoliths from the marine-brackish water transition from the middle miocene of the belgrade area, serbia.‒ paläontologische zeitschrift, 89/4, 815–837. doi: 10.1007/s12542-0150272-6 stevanović, p. (1951): donji pliocen srbije i susednih oblasti [pontische stufe im engeren sinne­obere congerienschichten serbiens und der angrenzenden gebiete – in serbian, with an german summary].‒ posebna izdanja sanu, clxxxvii, geol. inst., 2, 361 p. stevanović, p. (1970): paleogeografsko-ekoloske prinove iz tortona okoline beograda. [neue palaeogeographisch-őkologische beitrage zur kenntnis des tortons bei belgrade – in serbian, german summary].‒ glas sanu, cclxxviii, odelj. prir.mat. nauka, 33, 1–26. stevanović, p. (1985): diskussion der unterstufen slavonien und serbien.– in: papp, a., jámbor, a. & steininger, f.f. (eds.): chronostratigraphie und neostratotypen, miozän der zentralen paratethys 7, pannonien. akadémiai kiadó, budapest, 82–85. stevanović, p. (1990): die pontische halbbrackische molluscenfauna aus serbien und bosnien. ̶ in: stevanović, p., nevesskaja, l.a., marinescu, fl., sokač, a. & jámbor, á. (eds.): chronostratigraphie und neostratotypen: neogen der westlichen (“zentrale”) paratethys 8. pontien (1989). jazu‒sanu. zagreb‒beograd, 462–536. sušić, z., toljić, m., bulatović, v., ninkov, t. & stojadinović, u. (2015): present-day horizontal mobility in the serbian part of the pannonian basin; inferences from the geometric analysis of deformations.‒ acta geophysica, 64/5, 1626‒1654. sztanó, o., sebe, k., csillag, g. & magyar, i. (2015): turbidites as indicators of paleotopography, upper miocene lake pannon, western mecsek mountains (hungary).‒ geologica carpathica, 66/4, 331–344. doi: 10.1515/geoca-2015-0029 tari, v. & pamić, j. (1998): geodynamic evolution of the northern dinarides and the southern part of the pannonian basin.‒ tectonophysics, 297, 269‒281. ter borgh, m., vasiliev, i., stoica, m., knežević, s., matenco, l., krijgsman, w., rundić, lj. & cloething, s. (2013): the isolation of the pannonian basin (central paratethys): new constraints from magnetoand biostratigraphy.‒ global and planetary change, 103, 99‒118. doi: 10.1016/j. gloplacha.2012.10.001 ter borgh, m., radivojević, d. & matenco, l. (2015): constraining forcing factors and relative sea level fluctuations in semi-enclosed basins: the late neogene demise of lake pannon.‒ basin research, 6/27, 681–695. doi: 10.1111/bre.12094 toljić, m. (1996): neotektonski sklop avale (srbija). [the neotectonic pattern of mount avala (serbia) – in serbian and english].– ann. geol. pennins. balk., 60/1, 147‒157. toljić, m. (2006): geološka građa centralne vardarske zone između avale i kosmaja [geological setting of central vardar zone between avala and kosmaj ‒ in serbian, with an english abstract].‒ unpubl. phd thesis, faculty of mining and geology, university of belgrade, 162 p. toljić, m. (2016): tectonic evolution of the european margin and neotethys suture zone in the region of belgrade (northern šumadija-serbia).– wseas transactions on environment and development, 12, 268‒277. toljić, m., nenadić, d., stojadinović, u., gaudényi, t. & bogićević, k. (2014): quaternary tectonic and depositional evolution of eastern srem (northwest serbia) [kvartarna tektonska i depoziciona evolucija istočnog srema (severozapadna srbija) ‒ in english with an serbian summary].– ann. geol. pennins. balk., 75, 43‒57. toljić, m., matenco, l., stojadinovic, u., willingshofer, e. & ljubović-obradović, d. (2018): understanding fossil fore-arc basins: inferences from the cretaceous adria-europe convergence in the ne dinarides.‒ global and planetary change, 171, 167‒184. doi: 10.1016/j.gloplacha.2018.01.018 vasković, n. & matović, v. (1996): tercijarne vulkanske stene avale [the tertiary volcanic rocks from mt. avala ‒ in serbian and english].– ann. geol. pennins. balk, 60/1, 391‒414. wiedl, t., harzhauser, m. & piller, w.e. (2012): facies and synsedimentary tectonics on a badenian carbonate platform in the southern vienna basin (austria, central paratethys).– facies, 58, 523–548. doi: 10.1007/s10347-011-0290-0 geologia croaticageologia croatica evaluation of research in a bauxite-bearing area at the “crvene stijene” locality with emphasis on exploitation of the associated deposits  ivo galić1, dragan krasić2 & ivan dragičević3 1 department of mining engineering and geotechnics, faculty of mining, geology and petroleum engineering, pierottijeva 6, 10000 zagreb, croatia; (ivo.galic@rgn.hr) 2 ministry of economy, vukovarska 78, hr-10000 zagreb, croatia; (dragan.krasic@mingo.hr) 3 department of geology and geological engineering, faculty of mining, geology and petroleum engineering, pierottijeva 6, 10000 zagreb, croatia; (ivan.dragicevic@rgn.hr) doi: 10.4154/gc.2015.17 abstract in this paper we present and elaborate one research example when bauxite was the main target of the investigation. during reprocessing and reinterpretation of the original data from the “crvene stijene” locality near jajce in bosnia and herzegovina, it was established that bauxite hanging wall and footwall rocks in fact represent an even more valuable mineral resource, as “dimension stone”. the final goal of the research was to optimize the ratio between research and exploration costs and total profit by exploration of all available mineral resources in the area. for that purpose, a new research evaluation method encompassing both bauxite (primary resource) and associated deposits was developed and named the “integrated approach”. integrated, joint evaluation of bauxite and associated deposits (dimension stone), gives a far greater economic significance to whole area. finally, with this new method, the ratio between overall profit and cost will be optimized which results in significant increase in profit because all available deposits are considered for exploitation. also this method can be applied on abandoned mining sites if there is some secondary profitable mineral deposit in the mine area. keywords: bauxite deposits, dimension stone, associated deposits, integrated approach, jajce, crvene stijene 1. introduction due to its various applications, “dimension stone” is still very significant and indispensable in modern architecture. stone is one of the most durable materials in the form of protection and decorative panels of construction elements. from environmental protection aspects, its small greenhouse gas emission makes it a very applicable material in civil engineering. the dinarides are potentially a very rich area for exploration of many types of dimension stone with sedimentary origins. in this work we analyze the „crvene stijene“ locality near jajce in bosnia and herzegovina, which was studied for bauxite deposits throughout its long exploration history (fig. 1), while other associated deposits, (that can be a significant resource), were neglected. research without evaluation of every potentially profitable resource in the studied bauxite-bearing area can result with unnecessary costs and losses, which leads to significant uncertainty in terms of investment. therefore, the focus of this paper was to unify values of all profitable natural resources in the bauxite-bearing area of „crvene stijene“ with the new “integrated approach”. the primary difference between “the integrated approach” and previously utilized methods, is that the integrated approach, evaluates all associated resources in the area (in our case it is dimension stone in the footwall and hanging wall of bauxite deposits), beside the primary resource. it is even possible that associated resources have a higher market value than the primary resource. an example of such a case is the bauxite-bearing area of „crvene stijene“, where “the integrated geologia croatica 68/3 225–236 12 figs. 6 tabs. zagreb 2015 geologia croatica 68/3geologia croatica 226 approach” shows that dimension stone is much more profitable to exploit than bauxite. the expenses for additional research of the associated deposits are minor. with “the integrated approach” it is possible to determine the value of individual or overall deposits in the area and optimize the ratio between research and exploration cost and total profit. the primary goal of the investigation was to maximize the ratio between the total profit and research and exploration costs. finally, with the newly developed, integrated approach, we show that the overall expenses can be reduced and total profit can be significantly increased. 1.1. geological settings of the “crvene stijene” bauxite-bearing area fundamental lithostratigraphic features of cretaceous bauxites in the jajce area (localities: poljane, crvene stijene, bešpelj, liskovica) are defined on the basic geological map, sheet jajce, scale 1:100 000 (marinković & ahac, 1975) (fig. 2). the authors determined the stratigraphic age based on the biostratigraphic assemblage composition in the footwall and hanging wall strata. the footwall of bauxite deposits is always composed of shallow marine, red to white, figure 1: geographical location of the investigated site at “crvene stijene”. table 1: results of bauxite research in the „crvene stijene“ area. year number of boreholes the length of drilling reserve of bauxite research costs bauxite the total revenue from bauxite assessment profit from bauxite the share of research income n d qb cb tb vb pb pieces m’ t monetary u. monetary u. monetary u. % 1974 98 5 323 218 000 102 877 13 080 000 2 077 123 0,79% 1975 49 4 424 187 000 113 728 11 220 000 1 756 272 1,01% 1976 62 5 190 86 000 900 722 5 160 000 –40 722 17,46% 1977 60 6 622 92 870 588 893 5 572 200 339 807 10,57% 1978 67 6 298 146 430 414 494 8 785 800 1 049 806 4,72% 1979 48 6 315 164 760 661 787 9 885 600 985 813 6,69% 1980 35 6 169 61 824 441 777 3 709 440 176 463 11,91% 1981 27 4 747 2 000 407 252 120 000 –387 252 339,38% 1982 49 7 949 100 000 914 272 6 000 000 85 728 15,24% 1983 63 7 404 50 000 548 579 3 000 000 –48 579 18,29% 1984 81 10 968 2 000 623 728 120 000 –603 728 519,77% 1985 76 11 429 0 484 533 0 –484 533 – 1986 46 7 171 40 000 723 557 2 400 000 –323 557 30,15% 1987 10 2 194 20 740 130 869 1 244 400 76 531 10,52% 1988 11 3 189 10 000 135 731 600 000 –35 731 22,62% 1989 25 6 527 10 000 47 897 600 000 52 103 7,98% total 807 101 919 1 191 624 7 240 696 71 497 440 4 675 544 10,13% galić et al.: evaluation of research in a bauxite-bearing area at the “crvene stijene” locality with emphasis on exploitation of the associated deposits geologia croatica 227 well-layered limestones (fig. 2). the stratigraphic age is determined based on fossil remains (e.g. neoiraquia insolita, rudists; detail fossil determination in dragičević & velić, 2006) as albian-cenomanian (k1,2). hanging wall strata of the bauxite deposits are composed of carbonate clastic rocks (carbonate breccia, calcarenites and marls). their stratigraphic age is determined as senonian-campanian (2k2 3) (fig. 2). extensive and detailed research of the bauxite deposits (detailed geological mapping, geophysical, geochemical, palaeogeographic, investigations and especially drilling), that were undertaken after the basic geological map was produced, set the standard for determination of the footwall and hanging wall strata sedimentological characteristics of bauxite deposits. the footwall is always composed of limestones of albian-cenomanian age and the hanging wall is represented by carbonate-clastic rocks of senonian age. guided by these findings, numerous wells were drilled in other bauxite-bearing areas nearby, but bauxite deposits were, unfortunately, not found. a further step in defining the stratigraphic age of bauxite deposits in jajce was made by dragičević, 1987. detailed investigations of the microfossil content (fig. 5), defined the footwall rocks as albian in age and the hanging wall, carfigure 2: basic geological map of the investigated area (modified after marinković & ahac, 1975). geologia croatica 68/3geologia croatica 228 bonate-clastics, as being santonian-campanian in age (dragi čević, 1981, 1987 & 1997, dragičević & velić, 1994, 2006). 2. analysis of previous results of research on the foot wall and hanging wall deposits with empahssis on their valuation as a „dimension stone“ the “crvene stijene” area, near jajce was intensively studi ed from 1974 to 1989, with the focus on finding bauxite deposits and quantifying their reserves. more than 800 wells (with cores) and around 102 000 m’ of deposits were drilled (tab. 1). geological settings of the bauxite-bearing areas near jajce are shown on a detailed geological map (fig. 3) and structural settings of the “crvene stijene” locality are shown in a detailed geological section (figs. 4 & 5). 2.1. footwall deposits according to field observations, footwall carbonate deposits are classified as well-bedded, up to several meters thick and composed of light-grey and pink to white fossiliferous rudfigure 3: detail geological map of the bauxite-bearing area near jajce. galić et al.: evaluation of research in a bauxite-bearing area at the “crvene stijene” locality with emphasis on exploitation of the associated deposits geologia croatica 229 stone. dominating macrofossils are remains of gastropods and bivalves. the majority of the footwall layers are composed of shallow marine limestones with microfossil assemblages (fig. 5). dominating lithotypes are biomicrites, fossiliferous micrites, bioclastic-intraclastic-skeletal packstones and grainstones, occasionally wackestones with remains of molluscs and calcareous algae (fig. 5). rare, but very significant are sections with foraminifera, on which the detailed and precise stratigraphic determination of footwall deposits was made (dragičević, 1987). the microfossil population is exthe microfossil population is extremely low in the number of individual examples due to unfavourable palaeoenvironmental conditions during sedimentation. strong micritisation and partial recrystallization made it difficult to perform a palaeontological analysis. however, the existing fossil population was undoubtedly the key to determine the albian age of the footwall (dra gičević, 1987; dragičević & velić, 2006). data collected during later research in the karst dinarides indicates that the footwall carbonates with the bauxite deposits belong to the transition period from the lower to upper albian (dragičević, 1987; dragičević & velić, 1994). 2.2. bauxite in the “crvene stijene” area, bauxite deposits are the most significant mineral resource, which has been explored and exploited for more than fifty years (dragičević, 1987). complex, long-term and detailed research with a focus on bauxite deposits resulted in numerous valuable data about the geological settings, source of bauxite material, accumulation time, shape, size and spatial distribution of the deposits. all these data enabled the estimation of the exploration potential of the bauxite-bearing area in the jajce region. there are numerous deposits of high-quality red bauxite of various shapes and sizes. individual deposits reach up to 200 m in length, up to 100 m in width, and up to 40 m deep. the deposits are morphologically irregular in shape because some of them are elongated in the form of a channel, while others take the form of lenses. this morphological irregularity makes them difficult to research. the shape and size primarily depends on the palaeorelief depressions in the footwall carbonates which are primarily a result of chemical weathering during long-term emersions (approximately twenty million years) and the volume of transported bauxitesource material. based on data from numerous wells, individual palaeogeographic provinces (islands that were surrounded by sea), including the “crvene stijene” province, were determined. “crvene stijene”, just like other palaeogeographic provinces, is characterized by a number of bauxite deposits with significant volume of bauxite in a relatively small area. studies show that the palaeorelief wasn’t developed laterally from these provinces, so bauxite couldn’t be deposited there. the directly transgressive hanging wall also points to the same conclusion. in the bauxite-bearing area, the rocks of the hanging wall are usually coarse grained and composed of fragments of rudists, lithoclasts of basement limestones and fragments of bauxite. they are thick-layered, with variable thickness and composition of layers and laterally become fine grained with more stable thickness and petrographic composition in the flattened relief. paleorelief formation was strongly influfigure 4: detail geological section of the bauxite-bearing area of „crvene stijene“. geologia croatica 68/3geologia croatica 230 enced and controlled by tectonic fracturing of limestones in the basement. fracturing due to tectonics was the most intense in zones of the major faults, in which the biggest vertical movements occurred. intense tectonic activity also occurred on the margin of the carbonate shelf, where these rocks were exposed on the surface. tectonic activity created conditions for the formation of coarse-grained clastic sediments and regulated the growth of many rudist biohermas. clasts of rudist bioherms are often the constructive parts of the overlying carbonate breccias (dragičević, 1987; dragičević & velić, 1994). the described paleoambiental settings of the hanging wall can be used in bauxite deposit analysis, because potential areas can be distinguished by analyzing core data from wells. more than a thousand analyses were made from which the average composition of the basic components is presented (tab. 2) (dragičević, 1981) determined the chemical composition of the bauxite deposits. the mineral composition was also determined for several hundred analyses and is presented in table 3 (dragičević, 1981). the stratigraphic gap, or the terrestrial phase, during which conditions for bauxite sedimentation existed, lasted for about 23 million years. the phase started during the tranfigure 5: lithostratigraphic column of the bauxite-bearing area of „crvene stijene“. table 2: the average chemical composition of bauxite (in wt. %) (dra gičević, 1981). al2o3 sio2 fe2o3 tio2 cao lost of ignition 57.66 2.00 24.77 2.60 0.05 28,83 table 3: the average mineral composition of bauxite (in wt. %) (dra gičević, 1981). boehmite 64.1 kaolinite 3.9 hematite 28.4 anatase 0.7 calcite 1.5 other 1.4 sition from the lower to upper albian, during which the youngest footwall rocks were formed and lasted until the upper santonian-lower campanian age when the sedimengalić et al.: evaluation of research in a bauxite-bearing area at the “crvene stijene” locality with emphasis on exploitation of the associated deposits geologia croatica 231 tation of the oldest hanging wall began. according to the actual geological time-scales, this period lasted between 105 million and -83 million years. 2.3. hanging wall deposits hanging wall deposits to bauxites are calcareous breccia. layers are developed in the basal part of the hanging wall sequence. the layer thickness can exceed over ten meters but it is very variable both laterally and vertically. thickness variations are the result of sedimentation mechanisms and the shape of the basement of the accommodation space during deposition. breccia clasts are exclusively composed of footwall limestones (lower to upper albian age). fragments of rudists occur rarely and their size varies from the cm to m scale. they are usually angular or slightly rounded which indicates short or even practically no transport distances. the carbonate matrix varies in size from silt to sand sized particles subsequent processes of cementation and diagenesis resulted in the formation of a solid and homogenous rock with a massive habit. detailed documented structural settings for the “crvene stijene” area suggested a good structural condition and significant potential for obtaining blocks of dimension stone. layers are horizontal to slightly inclined (up to fifteen degrees), generally to the northeast, east and southeast (fig. 3). based on numerous fossil remains from the carbonate matrix in the breccia, hanging wall strata in the “crvene stijene” area are of upper santonian to lower campanian age (dragičević, 1987). 3. materials and methods from 2009 to present, new field and laboratory investigations were undertaken on rocks from the “crvene stijene” area. the focus was on the potential for exploiting the associated deposits in the footwall and the hanging wall of baufigure 6: hanging wall sequence of carbonate breccia in the „crvene stijene“ area. figure 7: a) mine gallery b) carbonate breccia in the walls of mining gallery. location of the mine gallery is in fig. 3. geologia croatica 68/3geologia croatica 232 xite deposits. both can be exploited as dimension stone. in the lower part of the productive hanging wall layer there is a mining tunnel, which represents an upper horizon for the “crvene stijene” pit, at an altitude of 900 m (fig. 6). in order to evaluate the quality of coarse grained breccia, a mine gallery was constructed about 200 meters to the north from the entrance to the mine, near the road to bešpelj (figs. 7a & b). a total volume of 110 m3 of coarse grained carbonate breccia was extracted from the mine gallery. 70 m3 of the extracted rocks could be used as a high quality dimension stone. 100 m to the south from the test gallery, a test cut for exploitation of the breccia dimension stone was made (fig. 8). from this location, blocks of breccia were also extracted for samples on which laboratory analysis were conducted. during 2015, five drill holes were made with a total core length of 520 m. the locations of all five wells are within 50-100 m from the mining gallery (fig. 7) and the test cut (fig. 8). samples from cores were analyzed in the commercial cemtra ltd laboratory in zagreb. the following physical and mechanical characteristics were determined: uniaxial compressive strength in the dry state and in water saturated conditions, uniaxial compressive strength, and flexural strength of the concentrated load, water absorption at atmospheric pressure, apparent density and density. furthermore, reinterpretation of the logs of earlier exploration drill holes (drilled from 1973 to 1989) was undertaken with the purpose of evaluating the associated deposits. 4. results results of the analyses are presented separately for bauxite and dimension stone, performed on an individual approach (i.e. each considered alone as a resource without reference to the other) and then according to the new, integrated method where both are considered together. 4.1. the results of bauxite analysis performed on an individual approach analysis of lithological columns from 807 well cores, resulting in the collection of detailed and precise data about the bauxite deposits (tab. 1). technical data about drilling, number of wells, drilling length and bauxite reserves were used for estimation of economic variables: research cost, profit from bauxite exploration and the significance of the conducted research in terms of the total profit. to obtain the total profit, the average production cost of bauxite, 20 €/ton (without drilling costs) with market cost of the mine, 30 €/ton were assumed. all economic categories are revalued at today’s value. prices are based on calculaprices are based on calcula-prices are based on calculations that were made for the main mining project of bauxite exploitation in bešpelj (galić et al., 2006). with such an individual approach to the bauxite research, the share of bauxite research costs in terms of total profit is 10,13 %, which is a very large amount. compared to the total profit, research costs are too high, which makes the exploitation economically unviable. 4.2. the results of analysis of dimension stone performed by an individual approach the research of dimension stone was based on prior interpretation of lithological columns from drill holes. the physical and mechanical characteristics of „dimension stone“ are presented in table 4. 4.3. valuation of reserves of dimension stone productive layers of dimension stone are up to 30 m thick but a thickness of 20 m was taken for further calculation to account for inconsistencies across the whole area. the area of investigation is 30 ha, but only 10 ha is considered in the figure 8: a) test cut b) carbonate breccia from the test cut. galić et al.: evaluation of research in a bauxite-bearing area at the “crvene stijene” locality with emphasis on exploitation of the associated deposits geologia croatica 233 research because of underground mining and protected zones in the potential underground mining area. estimation of the reserves of dimension stone was necessary in order to calculate other economic variables. the volume of dimension stone was estimated with the arithmetic mean value (popović, 1984): b av a d= ⋅ (1) v – volume of dimension stone (m3) ab – area of base (m2) da – average depth (thickness) of layers (m) 1 n ii a d d n == ∑ (2) di – depth of i layer (m) n – total number of wells total rock volume is calculated by applying the formulae (1) and (2) and reduced by a coefficient of efficiency which leads to dimension stone reserves. a coefficient of efficiency is the ratio of usable excavated rock to the total amount of excavated rock (galić et al., 2011; vidić et al., 2012). coefficients of efficiency in the mining gallery have reached a value of 0.60. a value of 0.15 was used for calculation since it is empirically determined for this type of deposit. the cause of such a low coefficient of efficiency are protective pillars and expected deposit countering losses. these losses are result of geological settings (faults, folds, fractures and fracture systems) in the deposit and exploitation losses. some economic variables like total cost, income, profit and research cost were calculated based on data about the market and production cost from previous research (dragičević et al., 2009). according to this, a production price of 500 units and market price of 700 monetary units was achieved. these values are listed in the research budget in the planned income. the fundamental expression for the net value of the reserves (galić, 2002) is: ( )t prvs qs c c= ⋅ (3) vs – net income of monetary units (m.u.) ct – market price (m.u./m3) cpr – production cost (m.u./m3) qs – the total amount of mineral resources, expressed in equivalent (eq), which will be exploited within the contours of the mine (for stone m3) based on input data, individual approach values for dimension stone in “crvene stijene” area were calculated (tab. 5). during the estimation of the proportion of research costs in total income, it was assumed that expenses will be identical to the expenses in previous analysis (analysis of bauxite deposits). results show that the market value of the dimension stone is multiples greater than the value of bauxite. also, the share of research costs in the total income is lower. this therefore emphasizes dimension stone as a more valuable mineral resource than bauxite and justifies the hypothesis that the overall, integrated evaluation of mineral resources facilitates the determination of their relative order of priority in exploitation. 5. discussion the results presented show that the final and decisive estimation of value of some mineral resource-bearing areas and share of research costs in total income value is only possible using table 4: physical and mechanical characteristics of dimension stone (breccia) determined from laboratory tests conducted on cores that were drilled in 2015 in the bauxite bearing area “crvene stijene”. type of test tested to results determination of uniaxial compressive strength in the dry state hrn en 1926 max.= 119.8 mpa (en 1926) min.= 98.3 mpa ave. = 104.2 mpa determination of uniaxial compressive strength in the water saturated condition hrn en 1926 max.= 109.1 mpa (en 1926) min.= 99.5 mpa ave. = 103.7 mpa determination of flexural strength of the concentrated load hrn en 12372 max.= 18.3 mpa (en 12372) min.= 12.3 mpa ave. = 13.7 mpa determination of water absorption at atmospheric pressure hrn en 13755 (en 13755) = 0.06 % (mas.) determination of apparent density hrn en 1936 = 2 675 kg/m3 (en 1936) determination of density hrn en 1936 = 2 680 kg/m3 (en 1936) geologia croatica 68/3geologia croatica 234 an integrated approach to their evaluation. the integrated approach analyses all mineral deposits in the chosen area, evaluates them and arranges them by economic priority. the fundamental equation for the calculation of total income of all mineral resources is: 1 m i i v v = = ∑ (4) vi – income of i-nd mineral resource where m is number of mineral resources partial values, presented in the previous chapter are summarized and shown in tab. 6. the second column shows the research costs that are nominally identical to the individual approach research costs. the third column shows the income and the fourth column shows total profit, which is significantly higher for the integrated than the individual approach. still, these data are indicative and should only be considered as orientation and not as exact values. it is important to remember the fact that the research cost for individual and all-inclusive deposits are almost the same. this is the main reason for the significant decrease in the share of research costs as a proportion of total income for both the individual and integrated approach methods. the final column, shows the conclusion of the analysis of the integrated approach. it presents the ratio between total profit and research cost. this parameter is the best indicator of the impact that research costs have on total profit. the indicator is named index of research flexibility and it can be evaluated by the following rankings: ir > 0 – profit is greater than the costs of research ir = 0 – neutral index, income is equal to the cost of research ir < 0 – no profit table 5: research results of the individual approach for assessment of dimension stone in “crvene stijene” area. average debth dimension stone area of base total volume coefficient of efficinecy reserve dimension stone research costs dimension stone the total revenue from dimension stone assessment profit from dimension stone the share of research income da ab v ce qs cds tds vds pds m’ ha m3 – m3 monetary u. monetary u. monetary u. % 20 10 2 000 000 0.15 300 000 7 240 696 210 000 000 60 000 000 3.45% table 6: relations of relevant variables in the integrated approach to the research of bauxite-bearing area “crvene stijene”. mineral resources research costs sales revenue profit the share of research income index of research flexibility   cr t v pr ir   monetary unit monetary unit monetary unit % ir = v : cr bauxite 7 240 696 71 497 440 4 675 544 10.13% 0.65 dimension stone 7 240 696 210 000 000 60 000 000 3.45% 8.29 total 7 240 696 281 497 440 64 675 544 2.57% 8.93 figure 9: relation between research cost and sales revenue (income). galić et al.: evaluation of research in a bauxite-bearing area at the “crvene stijene” locality with emphasis on exploitation of the associated deposits geologia croatica 235 figure 10: relation between research costs and total profit. figure 11: relation between income and share of research costs. by the proposed ranking, bauxite research (with individual approach) achieved positive results but on the edge of profitability, which makes the exploitation financially extremely risky. this confirms that the integrated approach to the exploration and exploitation of mineral resources is justified. further research of dimension stone, individually and integrated, with already existing input data from bauxite research, results in a very high index of flexibility. a high index of flexibility confirms the initial assumption that the integrated approach is justified and needed in the study of mineral resources in this particular area (figs. 9 & 10). these figures clearly show that research costs are constant. research costs can slightly increase if laboratory analyses are included but that is insignificant when considering the consequent increase in income. in figure 11, results of both the individual and integrated approach to analysis of research cost share in total income are shown. it is clear that individual costs share have a decreasing trend. the curve would be flatter if the analysis would include several mineral resources. figure 12. shows the relation between the index of flexibility and the border line in terms of profit, which clearly indicates the existence of the point of transition from positive to negative areas of viability. based on this, a deposit with overburden which has a negative index of flexibility was assumed. a negative index of flexibility means that there is no profit, only expenses. the diagram in figure 12 shows that the curve goes from a positive to a negative value which means that the research limits can be approximated. considering the location and the size of the bauxitebearing area (approximately 120 m below the surface, 75000 tons), the depth of the tectonic-erosional discordance and significant faults, drilling from the surface is uneconomical geologia croatica 68/3geologia croatica 236 for the existing conditions. therefore, new research and exploration methods should be developed and implemented in order to utilize these resources for exploitation. 6. conclusion research in the bauxite-bearing area of “crvene stijene” was extremely extensive and significant investment was made for finding bauxite and determining reserves. high quality limestones, dolomites and carbonate breccias compose the footwall and hanging wall of the bauxite deposits. high quality footwall and hanging wall rocks were never evaluated for any purpose. however, analyses of these footwall and hanging wall carbona te rocks show that these rocks can be very valuable dimension stones. with the proposal to evaluate these associated deposits, a new approach for evaluating resources for exploitation was developed. individual analysis of each of the deposits separately does not provide realistic results of the relationships between research costs, income and total profit. based on these drawbacks of the individual approach, a new, integrated method was developed which suggests the economic analysis of all primary and associated deposits altogether. bauxite deposits are located approximately 120 m below the surface, which increases the price of exploration and exploitation. reducing the price can be principally achieved by two methods: by introducing the integrated approach to research and by combining exploration methods. the integrated approach of research includes all the available resources in a particular area, which creates a synergic effect and reduces the overall share of costs in terms of total income. combined research methods can also increase efficiency by determining the depths of exploration wells. when the depth is known, exploration continues with underground mining techniques. references dragičević, i. (1981): geological settings in the bauxite-baering area jajce (in croatian).– master's thesis. faculty of mining, geology and petroleum engineering, university of zagreb, zagreb, 65 p. dragičević, i. (1987): palaeogeographic evolution of the edge of the mesozoic carbonate platform of dinarides between the vrbas and bosnia (in croatian).– phd thesis, faculty of mining, geology and petroleum engineering, university of zagreb, zagreb, 90 p. dragičević, i. & velić, i. (1994): stratigraphical position and significance of reef facies at the northern margin of the dinaric carbonate platform during the late jurassic and cretaceous in croatia and bosnia.– geologie mediterranee, tome xxi, no 3-4, 59–63, marseille. dragičević, i. (1997): the bauxites of the northern margin of the dinarides carbonate platform (area of jajce, bosnia). 8th internat. congress of icsoba, milan, april 16/18-1997, travaux, icsoba, vol. 24, 64–73, milan. dragičević, i. & velić, i. (2006): litostratigraphic settings of bauxite in the bešpelj area (in croatian).– geoeco.ing d.o.o. 30 p., zagreb. dragičević, i., galić, i., vranjković, a. & galić, m. (2009): elaborate of the reserves of dimension stone in exploitation field “kusačko brdo” in široki brijeg (in croatian).– proin 21 d.o.o., široki brijeg, 40 p. galić, i. (2002): mining design using specialized software, master’s thesis, faculty of mining, geology and petroleum engineering, zagreb, 95 p. galić, i., dragičević, i.i., živković, s.a., janković, b., radovac, t., kovacsics, á., hederics, j., podanyi, t. & hajsek, d. (2006): the main mining project of exploitation bauxite deposits on bešpelj (in croatian).– faculty of mining, geology and petroleum engineering, 495 p., zagreb. galić, i., vidić d. & jembrich, ž. (2011): the influence of the coefficient of utilization of reservoir feasibility of dimension stone production and improvement opportunities.– mining and geology bulletin, vol. 15, 117–130, mostar. galić, i. krasić, d. & knežiček, t. (2014): a defining the optimal point of opening and developing a surface pit mine.– acta montanistica slovaca, vol. 19, no 1, 47–59, košice. marinković, r. & ahac, a. (1981): basic geological map sfry, 1:100.000. sheet jajce, l33–131, “geoinženjering“ institute of geologysarajevo, federal geological institute, beograd. marinković, r. & ahac, a. (1981): explanatory notes for basic geological map sfry, 1:100.000. sheet jajce, l33–131, “geo inže njering“ institute of geology-sarajevo, federal geological institute, beograd. popović, n. (1984): the scientific basis of the design of open pit mines, ii. edition, veselin masleša, 971 p., sarajevo. vidić, d., galić, i. & farkaš, b. (2012): the profitability of dimension stone deposit exploitation in relation to the coefficient of utilization.– mining-geology-petroleum engineering bulletin, vol. 24, 123–130, zagreb. manuscript received april 15, 2015 revised manuscript accepted october 11, 2015 available online october 31, 2015 figure 12: relationship between the index of flexibility and the border line. vulama.indd 259 ivica vulama: source rock generative potential and volumetric characteristics of the kurrachine dolomite formation, hayan block, central syrian palmyrides � ab stra ct source rocks from the lower part of the triassic kurrachine dolomite formation were investigated in order to establish their role in the petroleum system of the hayan block. recent deep well discoveries accentuate the triassic kurrachine dolomite formation as a major play for hydrocarbon accumulations. the characteristic play defi nition is shown for the hayan block based on three defi ned elements: petroleum charge system, the source-reservoir formation characteristics and the trap-seal type. according to geochemical analyses, triassic source rocks are of good generative potential, but they are not abundant (only thin layers were estimated). it was presumed that hydrocarbon generation and migration occurred from deeper middle-lower palaeozoic formations. exploration results show that the generative potential of the triassic source rocks in the hayan block was underestimated. correlation and calibration of the petrophysical parameters from well logs and geochemical analyses show a much larger volume of mature source rocks than that predicted purely from geochemical analyses. the kurrachine dolomite formation resistivity of 20 ωm is typical of the area, and it represents the threshold value (net pay cutoff criteria) between immature and mature source rocks. net pay thickness (effective thickness), of mature and generative source rock intervals, exceeds more than 150 m in some wells. a calculated volumetric characteristic of source rocks indicates their high hydrocarbon generating capability. intensive tectonic activity formed fractured zones as favourable reservoir rocks, so in some areas, practically no or very short migration pathways exist. expelled hydrocarbons (within explored area) have not been accumulated into discrete reservoirs, thus the system is generating oil in situ. the results accentuate the existence of a key triassic petroleum system in the area of the hayan block. this petroleum system incorporates the triassic kurrachine dolomite, amanus shale formations and the permian amanus sand formation. keywords: source rock, triassic, kurrachine dolomite formation, amanus shale formation, amanus sand formation, volumetric characteristics, hydrocarbons generated, petroleum system, palmyrides, syria source rock generative potential and volumetric characteristics of the kurrachine dolomite formation, hayan block, central syrian palmyrides � ivica vulama 1exploration department, ina oil company, a. v. holjevca 10, 10 000 zagreb, croatia; (ivica.vulama@ina.hr) doi: 104154/gc.2011.22 geologia croatica 64/3 259–272 14 figs. 2 tabs. zagreb 2011 geologia croaticageologia croatica 1. introduction the characteristics of the triassic source rocks of the hayan block (ina oil company exploration concession) are illustrated. recent discoveries at the hayan block area indicate that the kurrachine dolomite formation is the most important source and reservoir rock formation. geochemical analyses estimated only thin layers and a small volume of source rocks, which is not commensurate with the amount of hydrocarbons discovered. calculated net pay value and volumetric characteristics of the explored source rocks suggest results different to those known previously. earlier work on this and the surrounding areas offer some interesting, but to some extent opposing conclusions about the potentiality of geologia croatica 64/3geologia croatica 260 the source rocks. leško et al. (2005) studied the source rocks of the hayan block in the central palmyrides. they concluded that the triassic sediments have good quality but a low quantity of source material, (only thin streaks of source rocks were estimated). abboud et al. (2005) correlated crude oils and source rocks from the mesopotamian foredeep, ne syria and the ne palmyrides. they defi ned the pre sence of two oil families generated by separate source rock types of different ages and concluded that the major source rocks for oils were the amanus shale and/or the kurrachine dolomite formations. vulama & špiljak vulama (2007) evaluated and correlated well-log data with geochemical analyses and seismic data. they found that the generative potential of the kurrachine dolomite formation of the hayan block was underestimated. according to well log data, mature generative intervals (net pay) of the lower part of the kurrachine dolomite formation exceeded 150 m. michels & malartre (2007) defi ned the existence of active source rocks in the triassic, with two oil types in the kurrachine dolomite formation. they recognized similarities in the content of biomarkers and maturity between the triassic rocks and oils. barić & smoljanović (2007) presumed that hydrocarbons within the reservoir rocks of the hayan block migrated from clastic rocks of carboniferous (markada) and silurian (tanf) ages. they supposed that middle triassic source rocks were of low volume, (thin strata of shale within the reservoir rocks of the kurrachine dolomite formation), with limited generative potential. hips & argyelan (2007) showed that the dark grey dolomite and mudstone of the kurrachine dolomite formation in a nearby area, contained an average corg of 2 %. the expelled hydrocarbons migrated within the kurrachine dolomite, or in some cases, to permian sandstone sequences. selective leaching, combined with tectonic activity (fractures), improved the reservoir potential of the kurrachine dolomite formation. vu lama (2009), completed the volumetric calculation of hydrocarbons generated from the lower part of the kurrachine dolomite formation. intensive tectonic activity, together with good generative potential, and the maturity of these rocks resulted in fracture zones acting as a favourable, in situ reservoir/source rock system. similar petrophysical characteristics were determined between the kurrachine dolomite and the amanus shale formation source rocks, and some geochemical correlations of source rock samples and crude oils indicate that the triassic petroleum system is a major play in the area of the hayan block. the main aim of this work is to show that source rocks of the triassic petroleum system have been underestimated in the sense of their generating capability, volume and areal extent. it is recognized that mature source rocks extend over a 220 m interval (vulama, 2009). estimated volumetric values show the high hydrocarbon generating capability of the source rocks. synthesis of all the evaluated data (well logging, geochemical analyses and 3d seismic), provides a new image and perspective on source rock distribution and hydrocarbon potential of the kurrachine dolomite formation. finally, the results presented here, suggest that this formation generates oil in situ, and represents favourable petroleum system in the area of the hayan block. 2. geologic setting the exploration area of the hayan block is situated in the central part of the syrian palmyrides, which represents a typi cal intracontinental convergent mountain belt. the palmyrides extend from the anti-lebanon mountain and dead sea fault system, in the southwest, towards the euphrates depression in the northeast, a distance of about 400 km over which they sink and disappear. they extend to about 100 km in width reaching heights of approximately 1400 m. to the north, the mountain belt borders the aleppo plateau, and the rutbah uplift to the south (fig. 1). structurally, the palmyride trough is composed of the alternation of highs where sediments of jurassic to neogene age outcrop, and depressions in which the sediments of neogene to recent age occur. two structural provinces exist. the southwest province includes the central palmyride ridge and folded zone of the southeastern palmyrides between which, the al-daww depression strikes ne–sw (fig. 1). the northeast province was separated by the jihar fault system, also striking in a ne–sw direction (mcbride et al., 1990; chaimov et al., 1990). exploration wells of the hayan block were drilled through deposits of mostly carboniferous to miocene age. an intensive tectonic history created complex and fractured structures (fig. 2). the sequence of sediments (source rocks) described (vulama, 2009) is most typical for the “b”, “j” and “m” fi elds (fig. 1). the most frequently drilled sequence starts with miocene sediments continuing with oligocene, eocene, palaeocene, upper and lower cretaceous sediments. next are lower-middle jurassic and upper triassic sediments, followed by the middle triassic (kurrachine dolomite formation), lower triassic (amanus shale formation), permian (amanus sand formation) and fi nally carboniferous (markada formation) sediments. the kurrachine dolomite formation is mainly compos ed of various carbonates. there is a rhythmic alternation of dolomite, limestone, evaporite and shale. the syrian general petroleum establishment divided this formation informally into several reservoirs: c2, d1, d2-1 and d2-2. of these, the c2 reservoir represents a series of rhythmically intercalated dolomite, limestone, claystone/shale, dolomitic shale and limy dolomite. the d1 reservoir is uniformly developed over the wider area. it comprises microcrystalline limestone, grading to dolomitic limestone and shale, while the d2-1 reservoir consists of limestone, dolomitic limestone, and dolomite intercalated with shale. a salt interval (d2) separates the d2-1 and d2-2 reservoirs, which have different hydrodynamic properties. the d2-2 reservoir consists of intercalations of silty shale and variations of limestone and dolomite sediments. the lower triassic (scythian) – amanus shale formation is composed of argillaceous shale, claystone, sandstone, siltstone, limestone and dolomite. sandstones/siltstones with intercalations of shale/claystone and dolomite, predominate in the permian – amanus sand formation. the carboniferous markada formation is a clastic sequence consisting mostly of shale interbedded with claystone. there are also sandstone, limestone, and dolomite beds which are up to se veral meters in thickness (fig. 3). geologia croatica 261 ivica vulama: source rock generative potential and volumetric characteristics of the kurrachine dolomite formation, hayan block, central syrian palmyrides 2.1. source rocks source rocks of the palmyride trough were classifi ed as proven and potential (metwalli et al., 1974; webb & thompson, 1994). proven source rocks occur at three levels in triassic strata and at two levels in rocks of cretaceous age. the amanus shale represents proven source rocks of triassic age. it is composed of black, calcareous marine mudstone and shale with a corg content of up to 20 % (average 8–9 %). the younger, kurrachine dolomite formation (figs. 2 & 3) is composed of interbedded dark grey dolomite, mudstone and limestone with a corg content averaging 2 %. the basal part of the butmah formation contains beds of anhydritic mudstone, several meters in thickness, with a corg content of up to 2 %. there are two proven cretaceous source rocks. in the euphrates trough, the soukhne formation (rmah chert and arak marl), is composed of black, bituminous, calcareous, cherty marine mudstones, with a corg content of up to 8.6 % and the shiranish formation with up to 14.3 % corg (metwalli et al., 1974; webb & thompson, 1994; hips & argyelan, 2007). the carboniferous source rocks of the markada formation were considered as having the most potential in the palmyride trough and they were proven in the euphrates trough. gas prone shales which passed through phases of the oil window and wet gas/condensate window in the early cretaceous occur in the markada formation. the source rocks of the markada formation (in the hayan block) contain shale and clayey shale of terrestrial/sapropelic origin (barić & smoljanović, 2007). the early silurian tanf formation is composed of dark partly silicifi ed marine mudstone. it can be correlated with known source rocks of similar age in oman, saudi arabia and south iran. by analogy, barić & smoljanović (2007) presumed that the tanf formation could also be the potential source rock in the hayan block area. the tanf formation is assumed to be overmaturing for oil throughout syria, except for the shallow parts beneath the aleppo platform (webb & thompson, 1994; michels & malartre, 2007). hydrocarbon occurrences in syria were proven in two petroleum systems – the triassic and cretaceous. the triassic oil system comprises source rocks of the amanus shale, kurrachine dolomite, mulussa and sergelu formations. triassic and cretaceous carbonates form the reservoirs. these systems actively generated oil in the late cretaceous, and wet gas and condensate during the neogene (webb & thompson, 1994). the authors together with michels & malartre (2007) considered the silurian oil system of the tanf formation and the carboniferous markada formation speculative, unproved systems. alsharhan & kendall (1986) pointed out that the small butmah oil fi eld in northern iraq, produces light oil from kurrachine limestone. this formation has both reservoir and source rock characteristics and it is composed of limestone with intercalations of thick-bedded dolomite and silty shale. source rocks of carboniferous, triassic, cretaceous and palaeogene age were determined on the hayan block (barić & smoljanović, 2007). palaeogene marl and limestone of the kermav formation were immature. cretaceous figure 1: index map of syria with the main tectonic units, dead sea fault sys tem (modifi ed after brew et al., 2001) and position of the hayan block in the palmyrides (with tectonic units and position of oil/gas fi elds: “a”, “b”, “j”, “m” & “p”; modifi ed after vulama, 2009). geologia croatica 64/3geologia croatica 262 deposits of the shiranish and soukhne formations were rich in organic matter, but mostly immature. occasionally they reached a maturity level of the early catagenetic phase. middle to late triassic source rocks of the kurrachine dolomite formation are rich in organic matter. they represent significant source rock in a regional sense (alsharhan & ken dall, 1986). carboniferous shales and clayey shales of the markada formation also indicate increased levels of organic matter of terrestrial/sapropelic origin. dark shales were classifi ed as medium to good gas prone and condensate source rocks (barić & smoljanović, 2007). 3. methods and samples hydrocarbon source rock parameters (geochemical analyses), including the type and amount of kerogene, and thermal maturity data, were assessed by the ina-naftaplin laboratory. net pay of source rock, volumetric characteristics, maturity and other source rocks characteristics have been determined through the correlation of well logs, 3d seismic and geochemical analyses. petrophysical (well log) characteristics of reservoir and source rock parameters have been interpreted on the basis of a broad-spectrum of well logs, which include: gr (natural gamma ray log), ngs (natural gamma ray spectrometry log), ac (acoustic-sonic transit time log), den (density log), cn (compensated neutron log), rt (true formation resistivity) & fmi (formation microscanner imager) logs. these well log data were used for various cross plots in statistical analysis and for correlation with geochemical and 3d seismic data. through statistical analyses discriminant function (d=0) was evaluated to divide source from non-source rocks. 3.1. geochemical characteristics of source rocks geochemical analyses of the triassic succession of “b”, “a” and “p” oil/gas fi elds of the hayan block show good generative potential and they are in a thermal oil generating phase. kerogene is of type ii and iii (tab. 1). 3.2. petrophysical characteristics of source and reservoir rocks petrophysical characteristics of source/reservoir rocks from the kurrachine dolomite formation (hayan block; d2-2 reservoir, respectively) were interpreted on the basis of numerous well-log derived parameters which include: gr, ngs, rt, ac, den, cn and fmi. (figs. 4–10). various crossplots (figs. 6–9) of ac/cn/den/rt/(ngs) logs were made to evaluate characteristic petrophysical parameters (figs. 4–6). evaluation of fmi logs indicates numerous conductive (open) fractures in the zone of source rocks. fmi logs of the kurrachine dolomite formation (also including the amanus shale formation) on “b” and “j” wells, shows typical fractable 1: geochemical parameters of kurrachine dolomite formation source rocks from “b”, “a” and “p2 oil/gas fi elds (see location on fig. 1). b a p triassic corg (%)= 0.48–5.32 corg = 0.46–1.80 corg = 0.32–4.72 s2 (mghc/gcorg)= 0.63–12.11 s2 = 0.49–2.96 s2 = 1.09–30.86 tai = 3–3+ tai = 3 tai = 2–3 (corg – total organic carbon content; s2 = pyrolisis content of hydrocarbons in kerogen; tai= thermal alternation index) figure 2: block diagram of the survey area showing the kurrachine dolomite formation and explored source rocks of “b” oil/gas fi eld area (see position of “b” on fig. 1). geologia croatica 263 ivica vulama: source rock generative potential and volumetric characteristics of the kurrachine dolomite formation, hayan block, central syrian palmyrides ture development in the carbonate zone and associated organic-rich layers – source rocks (high gr). additionally, the gr (ngs) of observed d2-2 reservoir shows a high uranium (238u) content ranging from 2–13 ppm (fig. 4). it is assumed that plankton and various organisms absorb uranium salts (ions) that are present in salt water, together with other rare elements. in this way the uranium is concentrated in the organic matter – source rocks (serra, 1979; schmocker, 1981). 4. results well log interpretation identifi ed the petrophysical properties of the reservoir and source rocks of the kurrachine dolomite formation. correlation and calibration of these petrophysical parameters and geochemical analyses was focused on the lower part of the kurrachine dolomite formation, which shows characteristics typical of mature source rock (figs. 2–4). maturity data were provided by geochemical analyses of the kurrachine dolomite formation from the hayan block area. as mature source rocks throughout the study area they have low to good generative capabilities, but according to geochemical interpretation they are low in quantity. the characteristic geological development of the hayan block area is expressed by thick salt layers (fig. 3) and signifi cantly fractured reservoirs (fig. 5). the consequence of these geological conditions was drilling with light oil based mud, blended with numerous organic additives. geochemical analyses were affected by contamination of cuttings and core samples. the sampling rate of the cuttings taken for geochemical analyses was usually every 20 m, which meant that some samples were not representative and non continuous for the purpose of characterization of source rock quality and quantity. figure 10 shows that samples taken for geochemical analyses have high variations in corg quantity rang ing from 0.56 to 5.32 %, with an average of 1.81 %. samples taken from low gr readings (assuming low gr = low organic c = poor source rock) shows low corg values and vice versa. average corg values calculated from well logs show a signifi cantly higher amount (2.22 %). corg was also measured from core samples taken from most favourable (limy, fractured) part of the reservoir, giving low readings of corg (0.08 to 0.30 %). this is also a non-representative, sporadic sample, for the purpose of evaluation of the source rocks. the core was cut from the most favourable zone (lowest gr reading, figs. 4 & 10) for reservoir parameter characterization (vulama, 2009). in addition, typical geophysical parameters were appraised by correlation of well-log (continuous) parameters with geochemical analyses and assorted samples of source rocks. 4.1. source rock data derived from crossplots the most common combinations used in this research were true resistivity (rt; ωm) vs. bulk density (den, ρb; g/cm3), and true resistivity vs. sonic transit time (ac, δt; μs/ft) crossplots (fig. 6). these combinations of two-component diagrams figure 3: schematic lithostratigraphic column of the hayan block with local lithology (after vulama, 2009) geologia croatica 64/3geologia croatica 264 proved to be useful for qualitative rock evaluation, especially when statistically estimated (figs. 6–9). when, crossplots were correlated with geochemical parameters, it was possible to determine the net pay of the mature source rocks by defi ning their typical resistivity values. the most often used crossplots include the following logs: true (formation) resistivity (rt) combined with volatile (free) hydrocarbons (s1), vitrinite refl ectance (ro) and tmax from "rock eval" analysis. crossplots were used to set the boundary value of formation resistivity at 20 ωm, thus separating mature from immature source rocks, and setting up the value of volatile hydrocarbons (s1) to be 0.20 mghc/g of rock, ro = 0.7 % and tmax = 436 °c (figs. 7, 8 & 9). 4.2. source rock data derived from statistical analysis and crossplots statistical analysis was applied in order to emphasize the simple classifi cation rules to distinguish source rocks from non-source rocks, based on quantitative well log parameters. these data which determined source rocks were fi ltered through several combinations of crossplots and then additionally checked through statistical analysis. the source rock well log parameters were recorded through organic rich deposits of the kurrachine dolomite formation. non-source rock parameters were logged at intervals above and below the source rocks (figs. 4 & 10). these parameters were divided into two classes, based on the geochemical analyses of rock samples: class 1 = source rock; class 2 = non-source rock. discriminant analysis (pseudoregression scheme, d=0) was performed in the statistical analysis (fig. 6). geophysical parameters (true resistivity, bulk density, sonic transit time, neutron porosity and natural radioactivity spectrum – uranium, respectively) were used as coordinates to locate the classifi ed rocks. figure 4: ac/cn/den/rt/ 238u logs of the kurrachine dolomite formation (“m-1” well). note 238u curve starting from 2 ppm and scale of neutron (nphi) curve starting from 0.02 (2 %). both are min. cut-off values for source and reservoir rock properties. figure 5: fmi logging of the kurrachine dolomite formation (“b-6” well), showing high fracture porosity of source rocks and adjacent zone. openconductive fractures are shown with sinusoids. geologia croatica 265 ivica vulama: source rock generative potential and volumetric characteristics of the kurrachine dolomite formation, hayan block, central syrian palmyrides figure 6: upper part of the fi gure shows a crossplot of resistivity (rt) and sonic interval transit time (ac, δt). d=0 (discriminant analysis). points above this line (d=positive) = source rock; points below line (d=negative) = non-source rock. lower part shows a crossplot of resistivity (rt) and bulk density (den, ρb). po ints above d=0 line (d=negative) = nonsource rock; points below line (d = po si tive) = source rock. figure 7: crossplot of resistivity (rt) and tmax showing 20 ωm and 436 °c as a min. values of mature oil-prone source rocks. geologia croatica 64/3geologia croatica 266 finally, according to the petrophysical interpretation, the kurrachine dolomite formation of the hayan block area is classifi ed as a signifi cant resource of source and reservoir rocks. well log analysis of reservoir properties (fmi; fig. 5) also proved that mature source rocks of the kurrachine dolomite and amanus shale formations are fractured, and they represent in situ source and reservoir rocks with no or short distance migration pathways. geochemical maturity parameters of source rocks were calibrated with electrical resistivity logs. a resistivity of 20 ωm represents the minimum cutoff value separating source rocks from none-source rocks figure 8: crossplot of resistivity (rt) and free (volatile) hydrocarbons (s1), showing 20 ωm and 0,2 mg hc/g as a min. values of mature oil-prone source rocks. figure 9: crossplot of resistivity (rt) and r0 showing 20 ωm and vitrinite refl ectance (r0= 0.7 %) as a min. values of mature oil-prone source rocks. table 2: geophysical and geochemical parameters of the kurrachine dolomite formation of the hayan block evaluated from the correlation of well logs and geochemical analyses. geophysical parameters geochemical parameters gr = 48–210 [api] corg = 0.48–5.32 [%] 238u = 2–13 [ppm] tmax = 436–448 (455) [oc] ac = 72–90 [μs/ft] s1 = 0.2–2.5 (5.18) [mg hc/g] den = 2.38–2.74 [g/cm3] s2 = 0.63–12.11(30,86) [mg hc/g] cn = 2–32 [%] ro = 0.7–1.25 [%] rt = 20–>350 [ωm] tai = 3–3+ geologia croatica 267 ivica vulama: source rock generative potential and volumetric characteristics of the kurrachine dolomite formation, hayan block, central syrian palmyrides (figs. 4, 7–9). a uranium content of 2 ppm (238u) was also statistically determined, together with 2 % neutron porosity (cn, nphi) as the lower (minimum) values for potentially good and mature source rocks and favourable producible reservoir parameters. these parameters were use for calculation of the net pay of mature source rocks (tab. 2). 4.3. volume of source rocks and generated hydrocarbons calculation of the volumetric characteristics of source rocks and hydrocarbons generated represents a step forward in the understanding and defi nition of the petroleum system. estimation of the amount of hydrocarbons generated from active source rocks, represents a basic element for evaluation of the expulsion, migration and accumulation processes affecting the effi ciency of the petroleum system. differences between the amount of hydrocarbons generated, compared to the amount in place, can be enormous. it is assumed that only a few percent of oil generated is recoverable oil for most basins, and up to 10 % of recoverable oil is generated in several sedimentary basins. this part of the article will deal with calculation of the mass of hydrocarbons generated in one part of triassic kurrachine dolomite formation, of the “b” wells fi eld (fig. 2, 11, 12 & 13). the schmoker (1994) method is the basis of calculations, which is, in this case, statistically controlled and improved in some parts by using 3d seismic data. the method is based on following elements (steps): 1. source rock identifi cation (wl, ga), defi nition of mapable boundaries and calculation of the volume of the homogeneous unit (wl, wl+3d). 2. calculation of the organic carbon mass in the source rock (wl, ga). 3. estimation of the mass of hydrocarbons generated per unit mass of organic carbon (wl, ga). 4. determination of the total mass of hydrocarbons through calculation. (wl=well log, ga= geochemical analyses, 3d= 3d seismic data) the volume, v (cm3), of the unit is calculated using 3d seismics calibrated with well logs in an effort to extract the unit from one particular part of the “b” wells of the hayan block (figs. 11–13). the calibration and correlation of the 3d seismic and well logs was undertaken after the well logs were correlated with geochemical analyses. therefore, we were able to calculate the net pay of the mature source rock with higher accuracy. for volumetric calculation of hydrocarbons generated, a potential source rock unit was bounded by physical fault boundaries to the south and west, but with a fi ctive ”contact” at –3 000 m to the north (fig. 11). the thickness of the unit was set at 70 m. following this setup parameters, the volume of the unit was calculated as (v) = 1.4x109 m3 (1.4x1015 cm3; fig. 12). the second step (fig. 12) is to calculate the mass of organic carbon m(gcorg), formula (1) m(gcorg) = [corg(wt%)/100] x [ρb(g/cm3) x v(cm3)] (1) the next step is to determine the mass of hydrocarbons generated per unit mass of organic carbon, r(mghc/gcorg) formula (2). the data needed to calculate r are the original hydrogen index hi0 (mghc/gcorg), prior to any hydrocarbon generation, and the present hydrogen index hip (mghc/ gcorg) of the source rock. the difference between these two indexes indices approximates the mass of hydrocarbons generated per gram corg. r(mghc/gcorg) = hi0 (mghc/gcorg) – hip (mghc/gcorg) (2) figure 10: sampled intervals (rectangles) for geochemical analyses from the b-5 well show high discrepancies in corg concentration. samples from the high gr zone show high concentration of organic matter and vice versa. the average value of 1.81 % is not a representative value for the lower part of the triassic kurrachine dolomite formation. calculated average corg concentration from well logs is 2.22 %. geologia croatica 64/3geologia croatica 268 the equation equates the decline in generation potential to hydrocarbons actually generated. the explored area of the hayan block has an initial index of 650 mghc/gcorg derived from immature source rocks of the kurrachine dolomite formation from “p” wells. the fi nal step is to compute the total mass of hydrocarbons generated hcg (kghc) computing the data from fi rst two steps: hcg (kghc) = r(mghc/gcorg) x m(gcorg) x 10–6 ( kg/mg) (3) following these equations, the volumetric calculation method was applied to one part (unit) of the kurrachine dolomite formation (figs. 10, 11 & 12). these parameters were calculated: – v = 1.4 x 1015 cm3 (1.4x109 m3), volume from 3d seismic) – corg = 1.84 mghc/gcorg (average data from ga – geochemical analysis), – ρb = 2.45g/cm3 (wl) according to equation (1) mass equals: – m = 6.32x1013 corg (1) for the second step present hip is 450 mghc/gcorg (ga), and initial hi0 is 650 mghc/gcorg, according to equation (2): – r = 200 mghc/gcorg (2) concluding with equation (3): – hcg = 1.27x 1010 kghc (3) converted to oil equivalent, using schmocker’s, (1994) graph, produces: 0.8 x 108 bbl or 12.7 x 106 m3 or 10.7 x 106 tons of oil equivalent. finally, taking into consideration evaluation of net pay of mature source rocks with discriminant factors rt= 20 ωm, 238u= 2 ppm and cn= 2 %, (vulama & špiljak vulama, 2007), the result must be reduced by approximately 20 % to hcg = 10.16 x 106 m3 or 8.6 x 106 (36 api) tons of oil equivalent. figure 12: seismic section through the “b” oil/gas fi eld with extracted source rock unit (yellow) and 3d shape (magenta) of the source rock body, 70 m thick (see location on fig. 1). figure 11: structure map on the top of the mature source rocks of the kurrachine dolomite formation of “b” oil/gas fi eld (see location on fig. 1). geologia croatica 269 ivica vulama: source rock generative potential and volumetric characteristics of the kurrachine dolomite formation, hayan block, central syrian palmyrides according to mcdowell (1975), recoverable oil is in the range of 10 % of the total oil generated, for only a few sedimentary basins, and is only a few percent for most basins. the difference between the amount of hydrocarbons generated, compared to the amount of oil in place can be enormous, due to the ineffi ciencies associated with the expulsion, migration, and trapping of hydrocarbons are often large. as schmocker (1994) pointed out, the parameters necessary to calculate the amount of hydrocarbons generated are poorly constrained, resulting in the calculation error. although disadvantageous, existing errors do not necessarily negate the value of volumetric hydrocarbon calculations because it is useful to know the range of the oil equivalent e.g. 1–10–100 millions tons of equivalent oil. 5. discussion recent hydrocarbon discoveries (“a”, “b”, “j”, “m” and “p“ oil/gas fi elds) in the hayan block showed that the triassic petroleum system is a major play in that area. the hydrocarbon potential of the kurrachine dolomite formation, (both reservoir and source rock properties as a system in situ) in previous explorations was not considered as signifi cant. herein, results and conclusions from previous work by authors from the ina oil company or their consultants are discussed. barić & smoljanović (2007) concluded that hydrocarbons of the kurrachine dolomite formation were probably of secondary origin (carboniferous and silurian ages). this secondary, migrated origin of hydrocarbons is not supported by the geochemical (“rock-eval”) analyzed data. these authors only presumed that the main regional source rocks were marine shale pellet deposits of the markada and tanf formations. data from geochemical analyses (with high hi content (450–620 mghc/g; in p-wells area even 555–650 for immature source rock in that area), and other geochemical parameters (tab. i) support a high generative potential for the kurrachine dolomite formation. following, in their conclusion, authors (barić & smoljanović, 2007) pointed out that middle triassic source rocks of the kurrachine dolomite formation were thin streaks of shale within the reservoir rocks of that formation, with limited generative possibility. this conclusion is also not acceptable as vulama & špiljak vulama (2007) confi rmed that more than 150 m of net pay of mature source rocks exists only in the lower part of the reservoir. these source rocks layers are not thin at all (figs. 4 & 10). barić & smoljanović (2007) emphasized that these source rock sequences (thin layers) are thermally mature, and that they reached the main oil window phase. the older sediments of the amanus shale and amanus sand formation, have restricted organic matter content (corg < 0.5 %). the conclusion of the existence of thin layers of source rocks was also addressed by previous work of vulama & špiljak vulama (2007) where it was shown that a lot of the geochemical tested samples were from non representative parts of reservoirs. this resulted in a much lower corg content and misleading conclusion about the low corg content, low capacity of source rocks and the conclusion of the existence of thin layers of source rocks throughout the entire kurrachine dolomite formation. the markada formation, in the area of the “b” wells, was only sampled by one deep well and both reservoir and source rock capacity, was low to medium and it has not been suffi ciently explored. michelis & malaltre (2007) confi rmed the existence of an active triassic source rock (with some reservations). strong similarities in geochemical characteristics between the oils from the kurrachine dolomite reservoirs and rock extracts from the triassic were determined. they proposed that oils from the kurrachine dolomite reservoirs were sourced from triassic source rocks. michelis & malaltre (2007) pointed out that they identify only oil prone source rock from the “rock-eval” data of the kurrachine dolomite formation from the “p” well. markada “rockeval” data indicate rather gas-prone immature to highly mature source rocks (ro= 1.31–1.54 %, tai = 3–3+, corg = 0.82– 1.07 %). concerning the tanf formation, they hypothesize that as it is deeply buried in the area, it must be over mature, (in addition – only one well drilled the tanf formation, some 45 km se from the “b” wells in the southern palmyrides). finally, in their conclusion they pointed out that they didn’t have enough good quality samples to analyze. the samples were either very altered by meteoric water input, i.e. water washing and biodegradation or contaminated by drilling fl uid. this conclusion can also be related to the evaluation of results from vulama & špiljak vulama (2007), who indicated the problems of contaminated samples which were mostly taken from non-representative parts of the kurrachine dolomite formation (non-source rocks zones) for geochemical analyses. this problem was solved after drilling the “m” well (fig. 4), where geochemical analyses were focused to selected zones with good source rock characteristics interfigure 13: interpreted detail of seismic profi le (see c-d, on fig. 11) of kurrachine dolomite formation (b-6 well). geologia croatica 64/3geologia croatica 270 preted from well logs (vulama, 2009). the samples were selected according to several criteria selected from correlation of well logs and geochemical analyses, in order to represent the most signifi cant parts of the reservoir with a special focus on formations bearing source rock potentiality. this means that the chosen rock samples have “rock-eval” characteristics of good to excellent source rocks, over an interval of 220 m, but only in the lower part of reservoir. selected representative samples helped to avoid the rock samples of equivalent facies but without proven oil potential (rock samples with unfavorable “rock-eval” characteristics). finally it can be concluded that geochemical analyses of the kurrachine dolomite formation from wells of the hayan block encountered contamination problems because of drilling with oil based mud and added organic additives. non-representative samples collected according to a program of ~20 m interval sampling were mostly out with the best concentrations of organic matter (source rocks, especially cores; fig. 4 & 10). this resulted in the conclusion of the existence of only thin layers of source rocks with low hydrocarbon generating capability. by interpreting continuous data from well logs, it was established that the entire kurrachine dolomite formation, especially the lower part, represents mature source rock with an effective net pay thickness of more than 150 m. this research defi ned marginal geophysical (well logging) parameters for mature source/reservoir rocks, the most important being the value of formation resistivity of 20 % ωm, and 238u content of 2 ppm and cn porosity of 2 %. favourable tectonic and sedimentation conditions (carbonates and shales sealed with thick salt-evaporite layers), signifi cantly affected and shaped this area. intensive tectonic activity played a double function – it shaped structures and traps, and formed fractured zones – reservoirs for hydrocarbon accumulation (fig. 13). mature and fractured source rocks, represent a signifi cant hydrocarbon generative and reservoir system in situ (oil in place), with no or minor migration path ways, as was regionally recognized in some surrounding areas. reservoir pressure measurements in the “b” fi eld well contributed to these results (fig. 14). the fi gure shows that three different, separated hydrodynamic units have various and mixed hydrocarbon saturation. if sources for these hydrocarbons were from silurian and carboniferous formations, deeply buried in this area (1000–1500 m deeper), it would be diffi cult to explain how the hydrocarbons migrated through these regional barriers in such amounts with such a high pressure difference and mixed composition. bearing in mind possible migrations through faults, we must take into consideration that deeper rocks are capable to generate only dry gas – as in the markada formation, or they can be overmature – as in the tanf formation. in the area of the hayan block, several major – regional barriers prevent migrations from deeper sediments, and they generate separated hydrodynamic units. the fi rst barrier is the regional shale layer of the amanus sand formation, which is up to 300 m thick. then there are two very thick salt/evaporite layers which may also exceed several hundred meters in thickness (figs. 13 & 14). figure 14: pressure gradients of kurrachine dolomite, amanus shale and amanus sand formations (“b” oil/gas fi eld). geologia croatica 271 ivica vulama: source rock generative potential and volumetric characteristics of the kurrachine dolomite formation, hayan block, central syrian palmyrides results presented here lead to the conclusion that an active triassic petroleum system exists in the area of the hayan block. hydrocarbon accumulations in syria were already proven in the triassic oil system which includes source rocks of the amanus shale, kurrachine dolomite, mulussa and sergelu formations and triassic and cretaceous carbonate reservoirs (metwalli et al., 1974, webb & thompson, 1994; abboud et al., 2005). in order to prove the triassic petroleum system as an important source and reservoir rock complex over the whole area, some additional work is necessary (i.e. the upper part of kurrachine dolomite formation also shows strong mature source rock characteristics). 6. conclusion investigation of the triassic kurrachine dolomite formation elements (source, reservoir, seal rock type and trap confi guration), was essential for petroleum system and play defi nition. it was found that according to geochemical analyses, the source rock potential was underestimated. geochemical analyses predicted only thin layers of source rocks which could not generate suffi cient amounts of hydrocarbons present in the triassic/permian reservoirs. moreover, it was presumed that hydrocarbons in triassic reservoirs were generated from deeper palaeozoic formations (barić & smoljanović, 2007). however, net pay of mature source rocks calculated from well logs showed much higher thicknesses of mature source rocks. a formation resistivity of 20 ωm is typical of the area and it represents the threshold value for mature source rocks and net pay calculating criteria. source rocks were also marked on 3d seismic sections. the calculated volume (from 3d seismic) and amount of generated hydrocarbons on the one part of the “b” wells fi eld highly supports the fi nal results and conclusions. triassic source rocks of the kurrachine dolomite formation in the area of the hayan block have signifi cant net pay of mature source rock, exceeding more than 150 m (through 220 m gross interval of source rock, which belongs only to the lower part of the reservoir). it was concluded that mature fractured source rock represents an in situ source and reservoir rock, and that either no hydrocarbon migration pathways exist or they were over very short distances. evaluated and compared well log petrophysical similarities between the kurrachine dolomite and amanus shale formations source rocks, supported with strong geochemical matching of source rock/oil samples, set the triassic petroleum system as a mayor play in the area of the hayan block. the triassic petroleum system is represented by the fractured source rock and reservoir system in situ – triassic kurrachine dolomite and amanus shale formations, respectively, and in some parts conventional permian amanus sand reservoirs. thick salt-evaporite layers represent the seals: d2 salt and salt on top of the kurrachine dolomite formation – bottom part of the kurrachine anhydrite formation. acknowledgement this paper represents one part of my phd thesis which was supported by ina oil company, with permission and thanks to josip križ, msc. željko ivković and msc. niko dalić. i am thankful to the reviewers prof. dr. josipa velić and dr. györgy pogácsás for their helpful guidance, supportive comments and suggestions that helped to improve this manuscript. special thanks go to vesna špiljak vulama for her technical support, maps and fi gures drawings and being co-author in previous research. i am also grateful to damir takač for 3d seismic interpretation, daniela križanić for fmi and marko živković for formation pressure data. i also thank prof. dr. mladen juračić for editor’s advice. references abboud, m., philip, p.r. & allen, j. (2005): geochemical correlations of oils and source rocks from central and ne syria.– journal of petrol. geol., 28/2, 203–218. alsharhan a.s. & kendall, c.g. (1986): precambrian to jurassic rocks of arabian gulf and adjacent areas: their facies, depositional setting, and hydrocarbon habitat.– amer. assoc. petrol. geol. bull., 70/8, 977–1002. barić, g & smoljanović, s. (2007): petroleum systems of the hayan block in the central part of syria.– nafta, 58/12, zagreb, 593–603. brew, g., barazangi, m., al maleh, a. & sawaf, t. (2001): tectonic and geological evolution of syria.– geoarabia, 6/4, 573–616. chaimov, t.a., barazangi, m., al-saad, d., sawaf, t. & gebran, a. (1990): crustal shortening in the palmyride fold belt, syria, and implications for movement along the dead sea fault system.– tectonics, 9/6, 1369–1386. hips, k. & argyelan, g.b. (2007): controls on diagenesis of the triassic kurrachine dolomite, syria.– geoarabia, 12/2, 41–64. leško, j., jasnić, l., krešić, a., tomašić, d., španić, d. & troskot-čorbić, t. (2005): basin modelling and hydrocarbon potential of northwestern part of the hayan block, syria.– proceedings 21/06, 3rd international oil and gas conference, zadar, naftaplin. mcbride, j.h., barazangi, m., best, j., al-saad, d., sawaf, t., al-otri, m. & gebran, a. (1990): seismic refl ection structure of intracratonic palmyride fold and thrust belt and surrounding arabian platform, syria.– amer. assoc. petrol. geol. bull., 74, 238–259. mcdowell, a.n. (1975): what are the problems in estimating the oil potential of a basin?– oil and gas journal, 73, 85–90. metwalli, m.h., philip, g. & moussly, m.m. (1974): petroleumbearing formations at northeastern syria and northern iraq.– amer. assoc. petrol. geol. bull., 58/9, 1718–1796. michels, r. & malartre, f. (2007) sequence stratigraphy and organic geochemistry of hayan block (syria).– unpubl. report, inanaftaplin, 133 p. serra, o. (1979): diagraphies differes-bases de l'interpretation. tome 1: acquisition des donnẻes diagraphiques.– bull. centre rech. expl.-prod. elf aquitaine, mem. 1 technip, paris, 328 p. schmoker, j.w. (1981): determination of organic matter content of appalachian devonian shales from gamma-ray logs.– aapg bulletin, 65, 1285–1298. schmoker, j.w. (1994): volumetric calculation of hydrocarbons generated.– in: magoon, l.b. & dow, w.g. (eds.): the petroleum system-from source to trap.– amer. assoc. petrol. geol. mem., 60, 323–329. geologia croatica 64/3geologia croatica 272 vulama, i. & špiljak vulama, v. (2007): source rock potential and maturity characteristics of kurrachine dolomite formation of central palmyrides in syria evaluated from correlation and calibration of well logs and geochemical analyses.– 4th international oil and gas conference, zadar, naftaplin, poster section, proceedings, zagreb, p. 127. vulama, i. (2009): geološke značajke i procjena naftnoplinskoga generativnog potencijala neogenskih i trijaskih matičnih stijena iz bušotina u hrvatskoj i siriji na temelju sinteze rezultata karotažnih, geokemijskih i seizmičkih mjerenja [geological characteristics and estimation of hydrocarbon potential of neogene and triassic source rocks from wells in croatia and syria based on the synthesis of the well log, geochemical and seismic data – in croatian, with an english abstract].– unpubl. phd thesis, faculty of mining, geology and petroleum engineering, university of zagreb, 205 p. webb, p. & thompson, s.j. (1994): country monitor syria, exploration monitor.– petroconsultants, syria, 218 p. manuscript received january 28, 2010 revised manuscript accepted july 21, 2011 available online october 26, 2011 geologia croatica 45 l 14 5 fig. 2 pl. 2 tab. zagreb 1992 udc 551.791:569.6 (497.13) scientific paper revision of the ungulate fauna and upper pleistocene stratigraphy of veternica cave (zagreb, croatia) l?reston miraclel and dejana brajkovjć2 key words: paleontolo gy, ungulates, upper pleistocene, paleolithic, croatia revision of the veternica ungulates removes dama dama (l.) (fallow deer) and megaceros giganteus (blumenbach) (giant deer) from the species list and adds bison priscus (boj anus) (bison) to it. the rhino remains do not allow a specific determination. a/ces a/ces (l.)(elk) and capreolus capreolus (l.) (roe deer) are rarer than previously thought. rupicapra rupicapra (l.) (chamois) re­ mains are particularly common in levels d and h. capra ibex (l.) (ibex) is limited to level d, while sus scrofa (l.)(pig) needs to be added to the faunallist of level e. cervus ela ph us (l. )(red deer) is the most common ungulate in all of the levels, with the exception of level d and perhaps level h. this revision remove s all of the so­ called warm period ungulates from the fauna and casts doubt on an interglacial date for level j. therefore, we suggest that level j at veternica does not date to the last interglacial maximum (oxygen isotope sub-stage se, e. 128-118,000 bp), but to a later and cooler time period with a more open environment. the sediments, how­ ever, do indicate relatively warm and wet conditions of deposition, at least with regards to the rest of the profile. we favor a date dur­ ing sub-stages sc or sa (e. 100,000 and 80,000 bp, respectively), but leave the question open for the time being. l. introduction veternica cave is a well-known site of paleontological, archaeological, and speleological interest. lt is particularly important for its abundant evidence of hominid and cave bear occupation during the upper pleistocene period. hominid occupation is shown by mousterian artifacts, probably manufactured by neandertals, and hearths, while cave bear use of the cave is inferred from the abun­ dance of th6r remains. the prehistoric significance of veternica was recognized by the late dr. mirko malez, wno comprehensively presented the results of his research in an admirable mono graph (malez, · 1963) and several articles (malez,1958/59, 1965). a paleontological revision of the veternica ungu­ lates was undertaken as part of a larger study by the senior author of the taphonomy of cave sites in croatia, and the evolution of hominid economies in this region during the upper pleistocene. in a recent publication, one of us (miracle, 1991) suggested that many of the cave faunas from middle and early upper paleolithic sites may bear a very weak inmrint of hominid activi­ ties. in particular, it was hypothesized, thatassemblages ključne riječi: paleontologija, ungulati, gornji pleistocen, paleolit, hrvatska revizija fosilne građe skupine ungulata veternice pokazala je odsutnost vrsta dama dama (l.) imegaceros gig ante us (blumenbach) i prisutnost vrste bison priscus (boj anus) . ostaci nosoroga nisu se pokazali dostatnim za odredbu vrste. u ukupnom fosilnom materijalu skupine ungulata, vrste a/ces a/ces (l.) i capreolus capreolus (l.) manje su zastupljene nego što se do sada mislilo dok je rupicapra rupica pra osobito prisutna u slojevima d i h. capra ibex (l. )ograničena je samo na sloj d, a faunskoj zajednici sloja e priključena je i vrsta sus scrofa (l) u svim slojevima, osim d i možda h, najbrojniji su ostaci vrste cervus elaphus l. učinjena revizija fosilne građe skupine ungulata vetemice ne potvrđuje svoju pripadnost toplodobnoj faunskoj zajednici kako se to do sada smatralo. mišljenja smo da se ni sloj j ne može datirati u posljednji interglacijalni maksimum (izotop kisika stadij se, cca 128-118.000 bp), već u kasniji i hladniji period s otvoreni jim biotopom. i u pogledu ostalih dijelova profila, sedimenti ukazuju na relativno tople i vlažne uvjete taloženja. prednost je dana datiranjima izotopom kisika, stadijima sc ili sa (cca 100 ili 80.000 bp), koji bi mogli odgovarati sloju j, no to pitanje ostaje otvoreno. dominated by cave bear and large carnivore remains were accumulated primarily through non-hominid processes. while the presence of many carnivores in cave faunas may appear to be explained by the activi­ ties of carnivores, the taphonomic status of ungulates in assemblages is impossible to untangle in the absence of detailed studies of the remains themselves (miracle, 1991). remains from veternica were originally examined as comparative material to aid the identification of remains from šandalja ii and other sites. when it became ap­ parent that there were a number of problematic iden­ tifications in the monograph (malez,1963), it was decided to review and revise the ungulate remains in earnest. 2. summary of the veternica sequence veternica is located about 9 km west of the center of zagreb, croatia, on the southwestern stope of medvednica (45°50'36" north, 13°32'24" east, 306 m above sea level, malez,1965, 176). the entrance to the cave faces south southeast and is about 8 m wide and 4 m high. the entrance chamber is about 15 ·m l museum of anthropology; university df michigan; ann arbor, mi 48109 usa 2zavod za paleontologiju i geologiju kvartara; a. kovačića s; 41000 zagreb croatia 2 long and 7 m wide (oriented east northeast-west south west with the entrance on the southeast corner) and receives direct sunlight for most of the day. beginning from the northwest corner of the entrance chamber, the "left hall" extends for 14 m and is j-7 m wide. leading off of the northeast corner of the entrance chamber is a narrow passageway that gives access to over lo km of pas­ sageways and canals. · quatemary sediments were excavated by malez (1965, 178; 1972) in the entrance chamber and left hall from 1951-1955, and in 1970, over an area of ap­ proximately 207 square meters (43 m2 in front of the entrance, 84 m2 in the entrance chamber, and 80 m2 in the left hall). in front of the cave, sediments were excavated to a depth of 8 m, while the entrance chamber and left hall were excavated to bedrock. in the most complete profiles, ll geological lay­ ers were identified. the first two layers, layers a and b, were black to brown in color, rich in organic material (particularly level a), and contained archaeological and faunal remains from the n eolithic to middle ages. these soils formed during the holocene and were found in front of the cave and in most parts of the entrance chamber and left hall. within the cave, but not in front of the entrance, these soils are underlain by dripstone, level e, which was barren of any remains except for a few floral remains of the following taxa: polypodium, pteridium, carex, and corylus (malez,l965, 202). carbonate samples from the upper and middle parts of level e gave mid-holocene c14 dates (5800±80 bp, z218/11; 5960±90 bp, z-194), while carbonate samples from the lower part of level e gave late pleistocene c14 dates (12,400±150 bp, z-218/1; 13,650±75 bp, grn4989; 13,660±180 bp, z-201) (malez,l979a, 218). beneath this dripstone cap, there were a series of lay­ ers deposited during the pleistocene. layers d, e, and f contain almost exclusively cave bear (ursus spelaeus ) remains. evidence of human occupation is very scan t; there are a few lithics and a "hearth" from level d (malez,l965, 203), and there are several non-diag­ nostic lithics from level/ (malez,l979b, 269). level g was found primarily in front of the cave and in the entrance chamber, and was sterile of archaeological or paleontological remains excepting a few cave bear bones near the contact with level h. level g consisted pri­ marily of rock rubble and probably marks a major roof collapse that closed the entrance to veternica (malez, 1965, 207). layers h, i, and j contain about 178lithics that have been attributed to human handicraft, of which at least 18 are mousterian "tools" (lithic totals calcu­ lated from malez,l958/59, 173, figure l; tool count from malez,l979b, plates xxix and xxx). a hominid calvarium from level h, considered by malez (1979b, 268) to be a neanthropic representative of "homo sa­ piens fossilis," has reen described by others as com­ pletely modem in ma:-phology and most likely redeposited from younger levels(smith,l982, 682). hearths were also found in all three levels, and charcoal from a hearth geologia croatica 45 in level i was radiocarbon dated at >43,200 bp (grn4984) (malez,l979a, 218). artifacts and ungulate remains were found piimarily in the entrance chamber. cave bear remains are still very common, and were found in the entrance chamber and left hall. hearths were found in both the entrance chamber and in front of the cave. o~ the basis of the sediments, associated fau­ nas and artifacts, layers h, i, and j were dated as wlirm l/ll interstadial, wlirm i stadial, and riss/wlirm in­ terglacial respectively (malez,l963, 153; 1965, 220222). the lowest level, k, was only found in front of the entrance and in the entrance, and did not contain any paleontological or archaeological remains. 3. paleontological revision perissodactyla dicerorhinus kirchbergensis (jaeger) four specimens were attributed to merck's rhino; a left m2 (vtr. 199), a first phalanx (vtr. 200), a third phalanx (vtr. 201) and a rib shaft fragment (vtr. 202), all from levelj (malez,l963, 108-112; plate xxii; plate xxiv, figure-:la-c). the relatively smooth enamel of the left second molar leaves little doubt that it is from the genus dieerorhinus. the remaining elements are very likely from the same genus, if not the same indi­ vidual as the mo lar. while metric comparisons (malez, 1963, 109-110) suggest that the molar and the phalanxes are too large to be from dieerorhinus etruscus, there is nothing to rule out the possibility that they are from dicerorhinus hemitoechus. as observed by several authors (loose,l975, 6; guerin,l980, 654) specific determination is extremely difficult on isolated teeth (particularly fower mo lars), let alone phalanxes and rib fragments. we suggest that a more prudent identifi­ cation of these remains is dicerorhinus sp. artiodactyla megaceros giganteus (blumenbach) malez (1963, 114-115, plate xxv, figure la-d), assigned three specimens to giant deer ( vtr. l, 2, 3). these are a navicular-cuboid and two third phalanxes. the navicular-cuboid (vtr. 3,levelj) is clearly bovid in morphology. in plate i it is compared to a navicular­ cuboid from a giant deer (see also malez,1963, plate xxv, figure la-d). in general shape, it is broader (medio­ laterally) and shorter (superior-inferiorly) than that expected from a cervid. the superior juncture between the facets with the calcaneus and astragalus is flat, as in bovids. similarly, the styloid on the plantar edge of the navicular is constricted medio-laterally, and in di stal view, the pos teri or articular facet with the metatarsal is ovoid in shape; both morphologies are characteris­ tic of bovids. this element is classified as bos!bison, since it does not show clear characteristics for specific determination. the third phalanxes (vtr. l and 2, both level i) both lack a large nutrient foramen immediately inferior and miracle & brajković : revision of the ungulate ... medial of the articular surface. a large foramen in this position is characteristic of giant deer and cervids in general. the phalanxes are also marked by well-de­ veloped articular facets for distal sesamoids on the posterior edge of the articular surface. such facets are typical of bovids, and rare or non-existent in cervids (plate i, figure 2a-b). therefore, these phalanxes are clearly from a large bovid, and are here only identified as bos!bison, since identification to species is very difficult (sala, 1986, 162). measurements made on these specimens did not differ significantly from those published by malez (1963, 114). dama cf. dama (l.) malez (1963, 115, plate xxvii, figure 3) from level j identified an upper right m3 as fal low deer (vtr. 41). close examination of the tooth shows a slight wear facet on its distal surface. in this case, the tooth can­ not be an m3, but rather must be either an m2, ml or dp4. measured at the base of the crown, its dimensions are: length (in mm) = 20.1 width (in mm) = 21.7 these dimensions are not significantly different from those published by malez (1963, 115). when com­ pared to the dimensions of upper molariform red deer teeth from upper pleistocene levels in sandalja ii, the specimen from veternica falls in the range of the ml (fig. 1). 28 i 26 :§. -5 24 "o l! ~ 22 20 18 16 o •• • upper teeth: length against breadth o " o o vtr.41 o 17 18 19 20 21 22 23 24 25 26 27 28 length (iit mm) o sa: upper ml o sa: upper m2 l> ša: upperm3 e sa: upperdp4 fi g. l. length against breadth al crown base of upper teeth in cervus elaphus from upper pleislocene levels from šandalja ii (miracle, un published) compared lo the molar identified as datnj dama from veternica (malez, 1963, 115, plate xxvii, figure 3). slika l. usporedba dužina i širina mjerenih na bazi kruna _gornjih zuba kod vrste cervus elaphus iz gomjopleistocenskih naslaga sandalje ii (miracle, rukopis) i molara iz veternice determiniranih kao vrsta datnj datnj (malez, 1963, 115, tabla xxvii, slika 3). given the morphology and dimensions of this tooth, it is most likely a right ml from cervus elaphus. one concludes that there are no identified remains of fal­ low deer from veternica. a/ces a/ces (l.) ~ /, malez (1963, 126-128; plate xxv, figure 2; plate xxviii, figures l, 7, 9; plate xxx, figure l; plate xxxv, figures l and 2) identified the following specimens as elk: an upper ml (vtr. 47, level h), a lower mt (vtr. 46, level h), a cervical vertebra (vtr. 3 48, level i ), an unfused distal epiphysis of a metacar­ pal (vtr. 45, level h or i), a calcaneus (vtr. 44, level i ), a navicular-cuboid (vtr. 4, level h ), a first pha­ lanx (vtr. 24, level i ), two second phalanxes (both level i), and a third phalanx (vtr. 5, level h). of these specimens, we are in agreement with the identifications of the teeth. the cervical vertebra (vtr. 48) is complete with a fusing caudal centrum and a fused cranial centrum. ·comparison with cervical vertebra of red deer, how­ ever, shows the specimen in question to be only slightly larger in size. the state of fusion of the centra makes it unlikely that the vertebra would have been much larger in an adult. if one considers that red deer during the pleistocene were· often larger than recent examples, then it appears quite likely that the specimen in question is from a red deer. in the absence of more complete comparative material, however, identification beyond the level of cervid is not warranted. the unfu~~d di­ stal epiphysis of a metacarpal (vtr. 45) is much closer in size to red deer than elk, and in fact, falls within the range of variation of other material identified as red deer from the site. the surface of the bone is compact and non-porous, suggesting that the epiphysis would not have grown much larger. therefore, we also identify this specimen as from red deer. the navicular-cuboid (vtr. 4) is extremely small for elk, and as shown in figure 2, better fits into the range of red deer; although the specimen is certainly from a very large individual. navlcular-cubold: gb against gd 60r-~~~--~~~~~--~~ 57.5 55 52.5 ~ 50 :§.47.5 o cl 45 42.5 40 :• 37.5 • o o ..• e\ • vtr.4 42.5 45 47.5 50 52.5 55 57.5 60 62.5 65 67.5 gb(inmm) o a/ces e cervus fig. 2. navicular-cuboid, greatest medio-lateral breadth (gb) against greatest dorsal-palmar depth (gd) in cervus and a/ces, compared lo the navicu1ar-cuboid identified as a/ces from veternica (malez, 1963, 127, plate xxv, figure 2). comparative data for red deer are from sandalj a ii (miracle, unpublished) and veternica. comparative data for elk are from pleistocene (malez, 1963, 127) and recent localities (malez, 1963; miracle, unpublished). slika 2. naviculare-cuboideum, odnos najveće širine (gb) i najveće udaljenosti (dorsalno-palmamo, gd) rodova cervus i a/ces u usporedbi s navikulamokuboidnom kosti roda a/ces iz v eternice (malez, 1963, 127, tabla xxv, slika 2). usporedni podaci za jelena su izšandalje ii (miracle, rukopis) i veternice. usporedni po.daci za losa su iz pleistocenskih (malez, 1963, 127) i recentnih lokaliteta (malez, 1963; miracle, rukopis). the calcaneus (vtr. 44) is in morphology from a red deer, although from a very large individual {fig­ ure 3). in red deer, the plantar edge ofthe articulation 4 with the navicular-cuboid is extended medially and fonns a right angle with the body of the sustentaculum tali. in elk, this articulation is not extended medially and f<x"rns an obtuse angle with the body of the sustentaculum tali. s6 54 s2 j so s48 e =46 o 44 42 40 • 38 • calcaneu: gd agalut gb • , • • • :' vfr44 o o o a/cu e cervus ~~~~~~~--~~--~~--~~-40 a 44 46 48 so ll 54 s6 ~ ro gd(inmm) flg. 3. cal cane us, greatest depth (dorsal-palmar) of the sustentaculum tali (gd) against greatest breadth (gb) in cervus and a/ces, compared to the calcaneus identified as a/ces from veternica (malez,l963, 127, plate xxx, figure la-b). comparative data for red deer are from šandalja n (miracle,unpublished) and veternica. comparative data for elk are from pleistocene (malez,l963, 127) and recent localities (malez,l963; miracle,unpublished). slika 3. calcaneus, najveća udaljenost (dorsalno-palmamo) sustentacula talusa (gd) u odnosu na najveću širinu (gb) rodova cervus i a/ces uspoređeno s kalkaneusom roda al ces iz vetemice (malez,l963, 127, tabla xxx, slika la-b). usporedni podaci za jelena su iz šandalje n (miracle,rukopis) i vetemice. usporedni podaci za losa su iz pleistocenskih (malez,l963, 127) i recentnih lokaliteta (malez, 1963; miracle,rukopis). the first phalanx (vtr. 24, see malez,l963, plate xxxv, figures l and 2) falls within the expected range of red deer, and well below the range for elk (figure 4). ~ phalanx 1: glpe against bp o o 32 o j 30 o g28 o a/cu ~26 e cervus • • • ., 24 • •• 22 • ••••• • vfr. 24 .,n • so ss ro 6s 70 7s 80 8s 90 glpe(inmm) fig. 4. phalanx 1: greatest length of the peripheral half (g lpe) against breadth of the proximal end (bp) in cervus and a/ces, compared to the ftrst phalanx identified as al ces from veternica (malez,l963, 127, plate xxxv, figures 1-2). comparative data for red deer are from š8ndalja n (miracle,unpublished) and veternica. comparative data for elk are from pleistocene (malez,l963, 127) and recent localities (malez,l963; miracle,unpublished). slika 4. phalanx i, najveća duljina periferne polovice (g4>e) u odnosu na širinu proksimalnog kraja (bp) rodova cervus i a/ces u odnosu na prvu falangu roda alas iz vetemice (malez,l963, 127, tabla xxxv, slike 1-2). usporedni podaci za jelena su iz šandalje il (miracle,rukopis) i vetemice. usporedni podaci za losa su iz pleistocenskih (malez,l963, 127) i-recentnih l~aliteta (malez, 1963; miracle,rukopis). . . our measurements differ somewhat from those published by malez (1963, 127). the measures are geologia croatica 45 as follows (in mm): glpe(greatest length of peripheral) = 65.9 bp (breadth of proximal) = 25.3 measures were not taken on the distal end due to a light abrasion of the distal condyles on their palmar surface. we also classify this specimen as red deer. all second phalanxes of cervids were locat~. but it was not possible to separate between those previously identified as red deer· and elk (the material was mixed during curation, and none of the measurements correspond to those published by malez [1963, 128] as elk). all of these specimens are well within the expected size range for red deer, and we have thus identified all of them as red deer. the third phalanx (vtr. 5) has been abraded on the anterior-medial surface. it lacks a large nutrient foramen imltlediately inferior and medial of the articular surface, has a well­ developed articular facet for a distal sesamoid, and the articular surface with the second phalanx ejs.tends supe­ rior-posteriorly in a manner characteristic of bovi ds. as discussed above for the giant deer, these are characteris­ tics of bovids, and we thus classify the specimen as b os/ bison. only two of the ten specimens originally identi­ fied as elk appear to be elk after further scrutiny. cervidae inc. sed. the right proximal metatarsal (vtr. 43, level b) is in morphology clearly from a bovid. its dimensions (in mm) are as follows: bp (breadth proximal) = 44.5 considering its small size it is identified as bos taurus. the vertebra (vtr. 118, level f) is a thoracic (not a cervical as previously identified), and is most probably from a red deer; its identification has not been changed. the mandible fragment without teeth (vtr. 125, level unknown) is from a bovid, and thus is classified as bosi bison. the left dp4 (vtr. 127, level i ) is in mor­ phology and size from a red deer. capreolus capreolus (l.) malez (1963, 129-130; plate xxxvi, figures l, 4-6; plate xl, figure 4) identified the following specimens as roe deer: a cast right antler (vtr. 148, level e), a fragment of right maxilla with dp3 and dp4 (vtr. 149, level d), a fragment of left mandible with p4, m1, mz (vtr. 150, level i ), a fragment of left mandible with dp4 and m1 (vtr. 151, level d), a right scapula (vtr. 152, level h), a left innominate (vtr. 153, level h), a left distal humerus (vtr. 154, level h), a right femur (vtr. 157, level d), a right dis tal tibia (vtr. 156, level j), a left calcaneus (vtr. 158, level e ), a right astragalus (vtr. 159, level e), a right 2nd-3rd carpal (vtr. 160), and a second phalanx (vtr. 155, level h). the right maxilla (malez,l963, plate xxxvi, fig­ ure 5) contains permanent teeth, a p3 and p4_ the right scapula is caprid in morphology; the glenoid fossa is sub-rectangular in shape and the supra-glenoid tubercle projects inferiorly of the articular plane. its dimensions miracle & brajković : revision of the ungulate ... are as follows (in mm): length (anterior-posterior) of proximal end = 32.6 length (anterior-posterior) of glenoid cavity = 25.2 breadth (medial-lateral) of glenoid cavity = 20.7 in morphology and size this scapula correspon~to that from the chamois. on the femur both proximal and distal epiphyses are unfused, making identification difficult nonetheless, the distal shaft has a lip on the an teri or edge that is characteristic of caprids, and thus we identify it as either chamois or ibex. the calcaneus (malez,1963, 130; plate xl, figure 4a-b) shows clear caprid morphology, especially in the extension of the astragalar facet inferiorly to the point that it contacts the articular facet for the navicular -cuboid. again, we identify it as chamois. finally, the second phalanx shows clear caprid morphology on both its proximal and distal articular surfaces. due to its relatively small size and gracile morphology, we identify it as chamois. these changes neither remove nor add roe deer to the faunallists from any of the levels. its remains, however, are much less common than previously thought, particularly in level h. bos primigenius (boj anus) malez (1963, 130-133; plate xxxvii, plate xxxviii; plate xxxix, figures 2, 3) identified the following specimens as aurochs: a left mt (vtr. 196, level j), a left mz (vtr. 197, level j), a left dp4 (vtr. 181, level j), a fragment of left dentary without teeth (vtr. 187, level j ), two thoracic vertebra (vtr. 182 and 198, both level h), a left dis tal humerus (vtr. 186, level j), a left diaphysis of a radius (vtr. 188, level ifj), three left metacarpal fragments (vtr. 183 and 184, level i; vtr. 185, level i/;), and one first phalanx (vtr. 187, level j). he specifically identified the humerus and metacarpal fragments as bos; the remainder of the material was assigned to bos on the basis of its asso­ ciation with these elements (malez,1963, 131). reconsideration of the humeral and metacarpal fragments suggests that they are either from bison or do not allow specific determination. to identify the distal humerus, one orients the bone so that the shaft is perpendicular to a horizontal plane. in this orienta­ tion, the medial epicot:~dyle (epitrochlea) of bos is extended distally so that it forms the most distal part of the humerus, while in bison, the trochlea and me­ dial epicondyle are on the same horizontal plane, i.e. the medial epicondyle does not extend distally below the tr~hlea (sala 1986, 138). the distal humerus (vtr. 186) is slightly damaged on the epitrochlea, making specific identification difficult. nonetheless, the damage is very superficial; it is unlikely that the medial epicondyle would have extended distally below the trochlea (see malez,1963, plate xxxviii, figure la­ b, plate xxxix, figure 3). this specimen is most likely from bison, probably bison priscus. its dimensions are as follows (in mm, the latter two measurements after lehmann, 1949): breadth of distal end = breadth of trochlea = depth of capitulum = depth of trochlea = 108.7 105.7 46.8 64.9 5 in identifying distal metacarpal fragments, among other criteria, in bos, the suture between the diaphysis and epiphysis is not evident in adults, while in biso n, the position of the s uture is visible and at this point the bone is widened (sala,1986, 143-144). one distal metacarpal fragment, vtr. 183, a lateral portion of a left metacarpal, shows a very distinct swelling of the bone at the position of the s uture (plate ii, figure la). also, comparison with bos material from sandalja ii (plate ii, figure lb), and biso n material from vindija shows similarities with biso n. therefore, this specimen is classified as bison. the other distal metacarpal fragment (vtr. 185) is a medial epicondyle of a left metacarpal. the bone is broken on or below the su­ ture, and it is impossible to identify it to species. it is classified as bos!bison. the remaining left proximal fragment (vtr. 184) includes the media! articular surface, which has a rounded dorso-medial angle and a slightly quadrangular or trapezoidal shape. on the basis of its morphology alone, one cannot specifically identify it. however, if it is part of the same metacarpal as vtr. 183, which seems likely, then it is of bison, and this is how we classify it. both molars, the deciduous premolar, and the dentary fragment are all part of the same left den tary. as malez (1963, 131) notes, it is difficult to specifically iden­ tify isolated teeth. nonetheless, both of the molars display features reminiscent of biso n. the left mt (vtr. 196) has a narrow ed neck and a pronounced swelling of the enamel at the base of the crown (plate ii, figure 2a-b). furthermore, it appears compressed mesio-distally (see malez,l963, plate xxxvii, figure 1). all.ofthese features are typical of bison (sala, 1986, 120). the left mz (vtr. 197, see malez,1963, plate xxxvii, figure 2) is broken at the base of the crown. never­ theless, there is a pronounced swelling of the enamel at the crown base. on the basis of the morphologies outlined above, both teeth are identified as b iso n priscus. the left dp4 (vtr. 181, see malez, 1963, plate xxviii, figure 2a-b) also shows an enamel swelling. at the base of the crown. this left den tary with three teeth is from a relatively young individual, probably between oneand two years of age since the mz is just coming into wear (eruption time pf the mz-in bison bison is about 18 months, prisan and reher 1970 cited in gifford.­ gonzalez, 1990, 58, eruption time in biso n bo nasus is between 12 and24 months, wegrzyn & serw atka, 1984, 118). specific identification based-oo-the material itself is very difficult. we place it in bison priscus because bison schoetensacki is found only in localities from the middle pleistocene (older than levels i and j in veternica), while bison bonasus is restricted to locali6 ties from the hol ocene (younger than levels i . and j in veternica). we further note that m bison bonasus, the breadth of the trochlea in the di stu humerus ranges from 74.5 mm 98.6 mm (lehmann,l949, table 181), considerably smaller than the specim~n from veternica (105.7 mm). we are most likely dealing with the "steppe" bison, bison priscus. the remaining elements lend themselves neither to generic nor specific identification. therefore, the thoracic vertebra {vtr. 182 and 198), a left diaphysis of a ra­ dius {vtr. 188), and the first phalanx {vtr. 187) are classified as from bos/bison. we note that the first phalanx is from the anterior limb. to them we can add the right patella already classified asbos!bison (malez, 1963, 133). rupicapra rupicapra (l.) we suggest only one change to the remains identi­ fied as chamois {malez, 1963, 133-134 ); the proximal tibia {vtr. 164) from level e is in morphology from a roe deer. capra ibex (l.) we have only one change for the ibex material (malez,1963, 134-136); the right innominate {vtr. 165, level e) identified as ibex (malez,1963, 135) is in morphology clearly from a pig. capra sp. all of the remains classified as from an undetermined caprid (malez,1963, 136-137) easily fall within the inventory geologia croatica 45 range of variation of chamois. this adds to the cham­ ois inventory from level h a radius (vtr. 169), metatarsal (vtr. 170), and lst phalanx (vtr. 171). ovis sp. the right humerus (vtr. 172, level d ) identified as an undetermined sheep (malez,l963, 137) is in morphology and by dimensions most probably cham­ ois. its dimensions (in mm) are: bd (breadth of distal end) = 32.8 the results of this revision are summarized in tables l and 2. fallow and giant deer have been removed from the species list, while bison has been added. elk and roe deer are rarer than previously thought, while ll specimens are now identif~ed as chamois. ch~mois remains are particularly common in levels d and h. lbex remains are found only in level d, while pig needs to be added to the faunallist of level e. on the other hand, red deer remains are slightly more common than pre­ viously thought, and include specimens from relatively large individuals. red deer remains the most common ungulate in all of the levels, with the ex~eption of level d and perhaps level h (if none of the h/il j material is from level h ). 4. discussion the implications of this revision for the paleoeco­ logical and stratigraphic interpretation of veternica, particularly level j, are significant. level j, the lowidentification numbers malez 1963 present study vtr. 1-3 megaceros giganteus bos/bison vtr. 5 a/ces a/ces bos/bison vtr. 4, 24, 44, 45 a/ces alces cervus elaphus vtr. 41 dama dama cervus elaphus vtr.43 · cervus sp. bos laurus vtr.48 a/ces a/ces cervidae vtr. 125 cervus sp. bos/bison vtr. 127 cervus sp. cervus elaphus vtr. 152, 155, 158 capreolus capreolus rupicapra rupicapra vtr. 157 capreolus capreolus rupicapra/capra vtr. 164 rupicapra rupicapra capreolus capreolus vtr. 165 capra ibex sus scrofa vtr. 169-171 capra sp. rupicapra rupicapra vtr. 172 ovis sp. rupicapra rupicapra vtr. 181, 183, 184, bos primigenius bison priscus 186, 187, 196, 197 vtr. 182, 185, 187 bos primigenius . bos/bison 188,189 vtr. !99-202 dicerorhinus kirchbergensis dicerorhinus sp. 2 phalanx ii a/ces a/ces cervus elaphus table l. summary of paleontological revisions to the identified veternica ungulate assemblage. tablica l. rezultati paleontololke revizije skupine ungulata iz spilje vetemice miracle & brajković : revision of the ungulate ... 7 nisp by level taxon d e f h l i/ p h i j total dicerorhinus sp . 4 4 sus scrofa 4 l l 6 a/ces a/ces 2 2 cervus elaphus 4 5 2 109 3 8 12 145 cervidae l l l 3 capreolus capreolus 2 3 l 2 l l lo bison priscus l 2 3 bos!bison l 3 3 2 l ll rupicapra rupicapra 5 l 5 ll capra ibex 3 3 total 19 lo 3 ll4 15 13 22 196 table 2. number of identified specimens (nisp) for ungulate taxa from the pleistocene levels of veternica. tablica 2. broj određenih uzoraka (nisp) pojedinih vrsta skupine ungulata iz pleistocenskih naslaga veternice. est level with paleontological or archaeological remains, has been dated as riss/wlirm interglacial on the basis of the characteristics of the sediments and the associ­ ated remains (malez,l 963, 152; malez,l965, 220221).2 malez (1965, 220) suggests that the near absence of a coarse fraction, the degraded state of the coarse fraction present, and the red color of the sedim en ts all indicate sedimentation during relatively warm climatic conditions. furthermore, he suggested (malez,l965 , 218) that calci um carbonate (cac03) is deposited in sediments under cold-humid conditions. as such, the low percentage of cac03 in level j (the lowest in the profile) is thought to indicate warm and dry conditions during the last (riss/wlirm) interglacial (malez,l965, 219). paleontologically, a warm climate was considered to be well-marked by the following species: dicerorhinus kirchbergensis (in particular) , dama dama, bos primigenius, s us scrofa , capreolus capreolus, hystrix cristata, and panthera pardus (malez,l963, 152154; malez,1965, 221 ). the mousterian artifacts are purported to be "primitive" and indicative of a riss/ wlirm date for level j (malez,1958/59, 182; malez, 1963, 154). "riss/wlirm," as used in the works cited above, clearly refers to full interglacial conditions. in terms of the oxygen isotope record (see shackleton, 1969; shackleton & opdyke, 1973), this refers to sub-stage se (e. 128-118,000 bp). the condition and composition of the sedim en ts from level j suggest deposition during relatively warm and humid conditions. the low frequency of the coarse fraction, the well"rounded character of the coarse fraction, and the high percentage of clays all suggest vigorous chemical weathering. while this is not the place for a detailed review of the pleistocene sediments of veternica, we would like to point out that the low percentage of cac03 in level j is more likely to be indicative ofhumid instead of dry depositional conditions. a relatively low value suggests that it was leached out of the sediments due to weathering. as iron oxide (fe203) is one of the residues of chemical weathering, one would expect higher percentages of it in levels that have witnessed relatively stronger chemical weathering. coilveniently, level j has the highest perce n tage of iron oxide in the veternica profile (malez,1965 , 218, table ii). furthermore, although external sources of clay cannot be ruled out (i.e. sediment brought in naturally or by human agents), it is commonly formed in place by the chemical weathering of sedi ments. it should thus indicate chemical weathering and relatively higher moisture. chemical weathering is dependent upon moisture to operate, and as a chemical process, will increase in rate with an increased temperature. therefore, increased chemical weathering should also indicate higher temperatures. relative to the rest of the profile, the climatic condi­ tions during the deposition of level j were probably both warmer and wetter. this interpretation is also suggested by ruka vina (1983, 210), who further notes evidence of a major cooling in the upper part of the level. if one turns to the associated fauna, this revision suggests considerable attrition to the "warm climate" assemblage of level j. fallow deer is not present, and the available rhinoceros material does not rule out the possibility that we are dealing with dicerorhinus hemitoechus instead of dicerorhinus kirchbergensis. dicerorhinus hemitoechus appears to have been a more obligate grazer, and its appearance in the place of or in addition to dicerorhinus kirchbergensis may in­ dicate the change from a temperate woody savanna to a cooler steppe environment (loose,1975, 23). in any case, dicerorhinus kirchbergensis is still present in europe l most of the red deer remains were not labelled by level and one cannot be sure of their exact stratigraphic provenience. however, malez (j 963, j j 6) notes that the majority of red deer bones were from levels h, i, and j, and that only a few bones were _f<;>und in the upper levels (d, e, and f ). following malez's observation, these unprovenienced bones are placed in the grouped level hill]. 2 in a later work (malez,j979b), he suggested that level j dates to the "upper part" of the riss/wiirm interglacial, although he neither gave a reason for modifiying this date nor elaborated on its chronostratigraphic implications. 8 during the early wiirm glaciation, including remains from hortus cave in southern france (guerin"l972, 207) and ćrni kal in slovenia (rakovec,19s8, 39s396). leopards have been found in a very wide range of pleistocene contexts and are poor indicators of environmental conditions (kurten,l968, 88). the crested porcupine is also found in a variety of inter­ glacial and glacial contexts (kurten,l968, 200) and does not necessarily indicate interglacial conditions. pig and roe deer may be more or less dependent on the presence of deciduous forest none of the taxa necessarily indicate an interglacial environment or date. previously, the presence of bison in assemblages has been considered indicative of cold and open environ­ mental conditions. research on fossil and recent mem­ bers of this genus, however, shows that they were adapted to a wide range of biomes and climatic conditions (bamforth,l988; sala,l986; vereshchagin & baryshnikov, 1984). the paleoecological signifi­ cance of biso n in veternica is difficult to evaluate due to the small number and poor condition of the remains. in passing, we note that the "primitive" aspect of the artifact assemblage is very much dependent on the raw material, in this case, volcanic tuffs, basalts, quartzites, andjasper (malez,l9s8/s9, 176). as malez (19s8/ s9, 176) notes, these materials are all available in grave! terraces from the nearby sava river and other locales years oxygen bp o isotope stage revised stratigraphy (this study) veternica levels l 20,000 2 d e 40,000 f 3 g 60,000 h 4 i 80,000 sa j sb v" sc l()() ,000 120,000 s d se 140,000 geologia croatica 45 in the immediate vicinity. furthermore, although the frequent use of quartzites in level j contrasts with raw material use at krapina (malez,l974, 16), close technological and typological similarities have been noted between the industry from level j at veternica and the middle paleolithic assemblages from the low­ est levels at erd in hungary (gabori-csank,1968, 2s8). the superposition of the erd artifact levels on a well-marked paleosol indicates a date young er than the last interglacial (gabori-csank,l968, los). the veternica artifacts from level j need not indicate an interglacial date. given the data presented above, we suggest that level j at veternica does not date to the last interglacial maximum (sub-stage se, e. 128-118,000 bp), but to a later and cooler time period with a more open envi­ ronment. in figure s we present our suggested revi­ sion of the stratigraphy and com pare it to the existing stratigraphic interpretation by using the oxygen isotope stratigraphy as a common measure.3 the sediments, however, do indicate relatively warm and wet conditions of deposition, at least with regards to the rest of the profile. the pollen spec tra for level j (malez,196s, 214) points to the presence of de­ ciduous species in the area, although such trees may have been restricted to fairly limited stands. in the absence of absolute dates, this leaves open a relatively wide time years oxygen bp o i s so tope l 20,000 2 40,000 3 60,000 4 80,000 sa sb 100,000 sc 120,000 s d 5e 140,000 tage original stratigraphy (malez,1963) veternica levels d post glacial e f wiirmill fl wiinnll/111 g wiirmll h wiinn l/ll i wiirml ~. j riss/wiirm ' flg. s. proposed revision of the veternica chronstratigraphy and the original stratigraphic interpretation (malez,1963, 153, figure 12), both compared to the oxygen isotope record (after gamble,l986, 76, figure 3.3). slika s. prikazi revidiranog i izvornog (malez,1963, 153, slika 12) kronostratigrafskog profila veternice uspoređeni s shemom izotopa kisika (usklađeno prema gamble,l986, 76, slika 3.3) 3 while malez never correlated the veternica profile with oxygen isotope stages, we note again that his emphasis on the "warm" and "interglacial" character of the fauna and sediments from level j suggests placement of this level in the warmest part of the riss/wiirm interglacial, sub-stage se. ;.. miracle & brajković : revision of the un gulate ... span in which to fit level j. we favor a date during sub­ stages sc or sa (e. 100,000 and 80,000 bp, respectively), but will leave the question open for the time being. our revision of the chronology of the veternica sequence is in close agreement with a little-known in­ terpretation given by s. brodar (1966) in a book review of malez's monographs. on primarily sedimentological and geomorphological grounds, brodar (1966, s19) suggested that level j dates to either a final phase of the riss/wlirm interglacial, or to an early wlirm in­ terstadial. in passing, he also noted that the "clacton" technique used in making the stone tools is found in many younger sites, and that the faunal remains, as published, do not indicate an interglacial date (brodar 1966, s19-s20). it is satisfying to find that our data provide such clear support for an interpretation now over 2s years old. support for the stratigraphic revision proposed above is provided by paunović (1991) in a study of changes in cave bear teeth from veternica. she observed that primitive tooth morphotypes characteristic ofriss glacial and riss/wlirm interglacial deposits are not represented in the veternica assemblages. the veternica cave bear teeth, in both their size and frequency of morphotypes, are most similar to more evolved wlirm populations of cave bears. therefore, working from several in­ dependent lines of evidence, we can conclude that the veternica sequence does not extend into the riss/wiirm interglacial. s. conclusion the net result of jhe paleontological revision is to squeeze the veternica pro file into a slightly tighter time frame. the earliest level with archaeological and pa­ leontological remains, level j, could have been de­ posited during a warmer phase towards the beginning of the wiirm glacial. level j is followed by two lev­ els, i and h, that also contained archaeological and paleontological materials. in terms of the associated faunas and material culture, these levels are very similar to j. by level h, the crested porcupine has gone and the elk appears. sedimentologically, these levels are very similar to each other, with the exception that the coarse fraction from h is more rounded and corroded (malez,1965, 209). these levels contain relatively less clay and iron oxide, and relatively more cac03 and rubble than level j, suggesting cooler and drier depositional conditions, perhaps during an early wiirm stadial. a single carbon14 date from level i, of> 43,200 bp (charcoal, grn-4984, malez,l979a) more or less confirms what we already know; levels i and j were deposited before e. 45·,000 bp. this revision also has implications for the recon­ struction of paleoenvironments in the area during the deposition of levels j to h. the un gulate assemblages from layers j h are very similar in composition. although the indeterminate rhino and pig are restricted to level j, and elk and chamois are found only in level 9 h, it is difficult to attach any importance to these changes due to the extremely small sample sizes for these taxa. in general, the faunal assemblages from levels j to h suggest a relatively temperate forest-steppe, perhaps with patches of deciduous woodland. together with the sites of krapina, vindija, and velika pećina, veternica provides a unique chance to moni­ tor the changing circumstances of hominid adaptation and evolution in southeastern europe (e.g. smith,1982). a first step to such a general study is an adequate identification, description and interpretation of the excavated data. we hope that the present study is successful on all three counts. our revision facilitates chronostratigraphic comparisons with other sites and adds to reconstructions of paleoenvironmental changes in the region. although we have not addressed the role of hominids in forming these assemblages, we have established a firmer contextual foundation from which to consider such questions in the future. 6. acknowledgments we would like to thank maja paunović for access to the veternica collections and for her support and good humor, and jakov radovčić for constructive com­ ments. responsibility for the final product, however, remains our own. we also thank slobodan olić for photographing the specimens. miracle's visit was made possible by a fulbright-hay s fellowship, irex, a nsf graduate fellowship, and a rackham disserta­ tion grant from the university of michigan. 7. references bamforth, d. (1988): ecology and human organiza­ tion on the great plains. plenum press, new y orle. brodar, s. (1966): knjižna poročila: malez, m. (1963):k vartarna fauna pećine veternice u medvednici. malez, m (1965): pećina veternica u medvednici. arheološki ves tnik xvii, 517522, ljubljana. gabori-csank, v. (1968): la station du paleo­ lithique moyen d'erd-hongrie. akademiai kaido, budapest. gamble, c. (1986): the palaeolithic settlement of europe. cambridge university press, cambridge. gifford-gonzalez, d. (1991): examining and refin­ ing thequooratic crown reight methxl of age estimation. -in: stiner, m.c. (ed): human predators andprey mortality.westview press, 41-78, boulder. guerin, c. (1972): le rhinoceros pleistocene de la grottede l'hortus (valflaunes, herault).in: de lumley, h. (ed.): la grotte mousrerienne de l'hortus.e tudes quaternaires, l, 207, marseille. guerin, c. (1980): les rhinoceros (mammalia, perissodoctyla) du miocene terminal au pleistocene supćrieur en europe occidentale. comparaison avec les especes actuelles. documents des laboratoires de geologie lyon, no. 79, lyon. kurten, b. (1968): pleistocene mammals of europe. lo weidenfeld and nicolson, london. lehmann, u. (1949): der ur im diluvium deutschlandsund seine verbreitung. -neues j ahrbuch fiir mineralogie, geologie und palliontologie abt. b, 90, 163-266, stuttgart. loose, h. (1975): pleistocene rhinocerotidae of w. europe with reference to the recent two-horned species of africa and s. e. asia.scripta geologica, 33,1-59, leiden. malez, m. (1958/59): das palliolithikum der veternica h~hle und der blirenkult quartlir l o/ll, 171-188, bonn. malez, m. (1963): kvartarna fauna pećine veternice u medvednici. palaeontologia jugosla vica, no. 5, zagreb. malez, m. (1965): pećina veternica u medvednici. l. opći speleološki pregled. n. stratigrafija kvartarnih taložina acta geologica, v, 175-237, zagreb. malez, m. (1972): kvartargeološka i speleološka istraživanja u 1971 godini.ljetopis jugoslavenske akademije znanosti i umjetnosti, 76, 215227, zagreb. malez, m. (1974): noviji rezultati istraživanja paleolitika u velikoj pećini, veternici i sandalji. -arheološki radovi i rasprave, jugoslavenske akademije znanosti i umjetnosti, 7, 7-44, zagreb. malez, m. (1979a): prirodni okviri. -in: basler, d. (ed.): praistorija jugoslavenskih zemalja i, paleolitsko i mezolitsko doba.svjetlost, 197219, sarajevo. malez, m. (1979b): nalazišta paleolitskog i mezolitskog doba u hrvatskoj. -in: basler, d. (ed.): praistorija jugoslavenskih zemalja i, paleolitsko i mezolitsko doba. svjetlost, 227-276, sarajevo. miracle, p. (1991): carnivore dens or carnivore hun ts? a review of upper pleistocene mammalian assemblages in croatia and slovenia. rad hrvatske akademije znanosti i umjetnosti, 458, 191-217, zagreb. geologia croatica 45 paunović, m. (1991): morphometrische und mor­ phogenetische untersuchungen der zlihne des ursus spelaeus rosenmiiller & heinroth aus der hohle veternica (nw kroatien). -rad hrvatske akademije znanosti i umjetnosti, 458, 1-19, zagreb. rakovec, i. (1958): pleistocenski sesalci iz jame pri črnem kalu. razprave iv razreda, slovenska akademija znanosti i umjetnosti, 4, 365-433, ljubljana. rukavina, d. (1983): o stratigrafiji gornjeg pleistocena s osvrtom na topla razdoblja i njihov odraz u naslagama na području jugoslavije. rad jugoslavenske akademije znanosti i umjetnosti, 404, 199-221, zagreb. sala, b. (1986): bison schoetensacki freud. from lsemia la pineta (early mid-pleistoceneitaly) and revision of the european species of bison. palaeontographia italica, 74, 113-170, pisa. shackleton, n. j. (1969): the last interglacial in the marine and terrestrial record. pr9ceedings of the royal society of london, b, 174, 135154, london. shackleton, n. j. & opdyke, n. d. (1973): oxygen isotope and palaeomagnetic stratigraphy of equatorial pacific core, v28-238.quaternary research, 3, 39-55, new york. smith, f. h. (1982): upper pleistocene hominid evolution in south-central europe: a review of the evidence and analysis of trends. current anthropology, 23, 667-703, chicago. vereshchagin, n. k & baryshnikov, g. f. (1984): quaternary mammalian extinctions in northern eurasia.in: martin, p.s. & klein, r.g. (eds.): quaternary extinctions. a prehistoric revolution. university of arizona press, pp. 483-516, tucson. wegrzyn, m. & serwatka, s. (1984): teeth eruption in the european bison.-acta therio­ logica, 29(9), 111-121, bialowieža. platetabla i la bos!bison, upper pleistocene, veternica level j (vtr. 3), navicular-cuboid, right, scale in cm; gornji pleistocen, veternica sloj j (vtr. 3), naviculare-cuboideum, desni, mjerilo u cm. l b megaceros giganteus (blumenbach), upper pleistocene, sandalja n level h (sa 1772), navicular-cuboid, left; gornji pleistocen, sandalja n sloj h (sa. 1772), naviculare-cuboideum, lijevi. 2a bos!bison, upper pleistocene, veternica level i (vtr. 2), phalanx ui, .scale in· cm; gornji pleistocen, veternica sloj i (vtr. 2), phalanx iii, mjerilo u cm. 2b megaceros giganteus (blumenbach), upper pleistocene, sandalja ii level i (sa. 472), phalanx iii; gornji pleistocen, sandalj a ii sloj i (sa. 4 72), phalanx iii. miracle & brajković : revision of the ungulate ... plate -tabla i ll 12 geologia croatica 45 revizija faune ungulata i stratigarafije gornjeg pleistocena spilje veternice (zagreb, hrvatska) p. miracle i d. brajković paleontološka revizija fosilne faune ungulata spilje veternice dio je opširne studije koju je započeo pres ton miracle s ciljem proučavanja tafonomija spilja hrvatske, uz razmatranja načina i uvjeta opstanka hominidnih zajednica tijekom pleistocena (miracle, 1991 ). preliminarnim pregledom fosilne građe veternice primjećena je određena nepodudarnost s do sada objavljenim rezultatima paleontološke obrade veternice (malez,1963), što je potaknulo potrebu za detaljnom revizijom. rezultati revizije (tablice l i 2) značajni su za paleoekološku i stratigrafsku interpretaciju veternice. taksonomskom obradom utvrđena je odsutnost vrsta dama dama i megaceros giganteus, ali i prisustvo vrste bison priscus. također je izmjenjeno kvalitativno i kvantitativno sudjelovanje vrsta a/ces a/ces i capreolus capreolus. rupicapra rupicapra je osobito zastupljena u slojevima d i h. capra ibex utvrđena je jedino u sloju d, dok je paleofauni sloja e pri dodana i vrsta s us sc roja. ostaci vrste cervus e/aphus ukazuju na pripadnost krupnim jedinkama, i ta je vrsta u cjelokupnoj fosilno j građi najviše zastupljena. od skupine ungulata jelen dominira u gotovo svim slojevima. do sada je sloj j, najstariji sloj koji sadrži paleonto­ loške i arheološke ostatke, po svojim sedimentološkim i faun ističkim karakteristikama bio datiran u interglacijal riss/wlirm (malez, 1963, 152; malez, 1965, 220221). malez (1965, 220-221) je tvrdio: "toplodobni karakter sloja j vrlo dobro markiraju neki predstavnici faune, i to u prvom redu nosorog vrste dicerorhinus kirchbergensis, zatim jelen lopatar (dama cf.dama), dikobraz (hystrix cristata minor), leopard (panthera pardus ), divlja svinja (sus scrofa), srna (capreo/us capreolus), divlje govedo (bos primigenius) i drugi". isti autor smatra da sakupljeni musterijenski artefakti iz sloja j pokazuju "primitivne" karakteristike te indiciraju datiranje sloja u riss/wlirm (malez,1958/59, 182; malez,1965, 221). sastav sedimenata sloja j sugerira taloženje u relativno toplim i vlažnim uvjetima, a revizija faunske asocijacije upućuje na određeno "osipanje" toplodobnih elemenata. tako je primjerice utvrđeno odsustvo vrste dama dama, a ostatke nosoroga nije moguće točno determinirati kao vrstu dicerorhinus kirchbergensis ili možda vrstu dicerorhinus hemitoechus. panthera pardus i hystrix cris tata bili su široko rasprostranjeni tijekom pleistocena čime gube vrijednost kao indikatori klimatski prilika (kurten, 1968, 88, 200). sus scrofa, i capreolus capreolus nisu karakteristične vrste za određenu ekološku nišu. biso n priscus nekad se smatrao predstavnikom isključivo hladnodobne faunske zajednice ali danas je to mišljenje izmjenjeno (bamforth,1988; sala, 1986; vereshchagin & baryshnikov,1984). uslijed malobrojnih ostataka bizona u naslagama veternice teško je govoriti o paleoekološkom značaju ove vrste. prije ustvrđena određena "primitivnost" izrade musterijenskih artefakata, zapravo veoma ovisi o vrsti materijala koji je bio upotrebljen. artefakti iz veternice izrađeni su od vulkanskih tufova, bazalta, kvarcita i jaspisa koji su se mogli prikupiti u šljunčanim nanosima save i u neposrednoj blizini spilje. no neophodno je napomenuti da navedeni paleolitski materijal ne mora indicirati starost sedimenta. po rezultatima dobivenim u ovom radu smatramo da se sloj j u veternici ne može datirati u posljednji interglacijalni maksimum (izotop kisika, stadij se, cca 128-118.000 bp, shackleton,1969; shackleton & opdyke,l973), već u kasniji i hladniji period s otvoren ijim biotopom. sastav faune ungulata sličan je u slojevima j h. općenito sastav fa unske zajednice u ovim slojevima upućuje na razmjerno umjerene klimatske uvjete i na šumsko-stepski okoliš s rijetkim bjelogoričnim šumarcima. i u pogledu ostalog dijela profila, sedimenti ukazuju na relativno tople i vlažne uvjete taloženja. metodom 14c datiranje sloj i na starost plate tabla ii la bison priscus (boj anus) upper pleist.ocene, veternica level j (vir. 183), metacarpal, right, scale in cm; gornji pleistocen, veternica sloj j (vir. 183), metacarpus, desni, mjerilo u cm. lb bos primigenius (bojanus) upper pleist.ocene, šandalja ii level gh (ša 1269, 1266), metacarpal, left; gornji pleistocen, šandalja ii sloj gh (ša 1269, 1266) metacarpus, lijevi. 2a bisonpriscus (bojanus) upper pleistocene, veternica level j (vtr. 196), mt. left, scale in cm; . gornji pleistocen, veternica sloj j (vtr. 196), m1, lijevi, mjerilo u cm. 2b bos primigenius (bojan us) upper pleistocene, š an dalja ii bic (š a. 7398),level bid, m1, left; gornji pleistocen , šandalja ii sloj bic (ša. 7398), m1, lijevi. ;.. :. miracle & brajković : revision of the ungulate ... • plate ·tabla ii 13 1 2 14 veću od 43.200 bp (ugljen, grn-4984, malez,l979a). period taloženja naslaga teško je odrediti bez apsolutnih datiran ja. prednost dajemo datiranjima s izotopom kisika, stadijima 5c ili 5a (cca 100 ili 80.000 bp), koji bi mogli odgovarati sloju j, no to pitanje ostaje otvoreno. veternica, uz ostale lokalitete, krapinu, vindiju i veliku pećinu, pruža jedinstvenu mogućnost promatranja svih okolnosti evolucije i adaptacije čovjeka u prostorima jugoistočne evrope. prvi korak prema širim znanstvenim geologia croatica 45 proučavanjima je odgovarajuća odredba, opis i tumačenje sakupljenog materijala. nadamo se daje ova rasprava ispunila sva tri uvjeta. cilj učinjene revizije je da olakša kronostratigrafske usporedbe s drugim nalazištima te da doprinese rekonstrukcijama paleoekoloških i paleo­ zooloških uvjeta tijekom gornjeg pleistocena u ovim prostorima. premda u oblikovanju faunskih zajednica uloga čovjeka nije određena, vjerujemo da ova rasprava pruža pouzdane osnove za otvaranje nekih novih pitanja. manuscript received march, 31. 1992. revised manuscript accepted may, 25.1992. 2018 | 71/2 | 47–53 | 7 figs. | 3 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction advances in medicine and the common use of pharmaceuticals have resulted in the presence of such compounds in both surface and groundwaters as well as in geological sediments (watkin­ son et al., 2009; zuccato et al., 2010; bu et al., 2013; wu et  al.,  2014; boroń & pawlas,  2015; yao  et  al.,  2017).  identification of a mathematical model and parameter estimation of erythromycin migration in two different porous media, based on column tests monika okońska and katarzyna pietrewicz adam mickiewicz university in poznań, institute of physical geography and environmental planning, krygowskiego 10, 61-680 poznań, poland; (okonska@amu.edu.pl) doi: 10.4154/gc.2018.05 abstract the amount of pharmaceuticals found in groundwater has risen over the last few years. erythromycin is an example of an antibiotic widely used in human health care and veterinary practice that can be transported into the subsurface. the aim of the presented research was to 1) determine the mathematical model of erythromycin migration in two different porous media, 2) estimate the model parameters and 3) compare the migration of the antibiotic in the investigated media. the research was conducted in a specially prepared laboratory stand where column tests were performed. one column was filled with glass granules (70% sio2, 600–800 µm in diameter) and the second column was filled with a natural sediment (sandur sand). the migration of a conservative tracer and erythromycin was examined in both columns. the experiments were performed in two separate steps. in the first step, a conservative tracer, subject to advection and dispersion processes, was injected into the coluand its transport was investigated. the second step involved investigating the migration of erythromycin. a conductivity meter was installed at the output of the column in order to determine tracer concentrations based on calibration curves. short-time pulse injections and continuous injection were applied during the experiments. an interpretation of the experiments results was conducted in the matlab environment. a mathematical model of erythromycin migration was determined from the shape of pulse breakthrough curves, which were characterized by a set of descriptors: the time of maximum tracer concentration at the output tmax, the spread of the breakthrough curve s, and relative tracer recovery e. this procedure involved implementing an identification algorithm developed by the authors. it was proved that the migration of erythromycin is best described by a hybrid model that assumes the coexistence of equilibrium and non-equilibrium sorption. in the next stage of the research, the transport and sorption parameters were estimated through numerical optimization procedures. the convergence between theoretical and experimental breakthrough curves was analysed qualitatively by calculating the root mean square error rmse and correlation coefficient r.  pharmaceuticals entered into the circulation of substances con­ nected with the hydrological cycle (fig. 1) (kümmerer, 2008;   mompelat et al., 2009; zając et al., 2013). the list of the  pharmaceuticals which need to be monitored includes erythro­ mycin – a macrolide antibiotic used in human health care and veterinary practice (de voogt et al., 2009; ma et al., 2015). article history: manuscript received june 16, 2017 revised manuscript accepted january 24, 2018 available online june 21, 2018 keywords: groundwater, erythromycin, sorption, optimization sewage treatment plant sewage surface waters landfill sites groundwater waste unused pharmaceuticals pharmaceuticals consumed by humans excretion soil manure excretion pharmaceuticals as feed additives leaky pipes surface runoff figure 1, okonska & pietrewicz figure 1. the migration of pharmaceuticals into groundwater (after zając et al., 2013). g eo lo gi a c ro at ic a geologia croatica 71/248 according to research findings, the effectiveness of removing  erythromycin from the contaminated water in the sewage treat­ ment process varies, and the percentage elimination of erythro­ mycin depends on the technologies applied, i.e. the conventional or advanced treatment (watkinson et al., 2007; boleda et  al., 2011; czech, 2012; al qarni et al., 2016). hence, there is  a possibility that the antibiotic reaches the subsurface environ­ ment. according to the literature, cases of erythromycin presence in groundwater have already been reported (peng et al., 2014;  ma et al., 2015; yao et al., 2017). therefore, it is very important  to investigate the conditions of erythromycin migration in natural porous media. bu et al. (2013), among others, pointed out the need  for better understanding of the transport and fate of pharmaceu­ ticals, including erythromycin in various media. such study was conducted to recognize the leaching of erythromycin through po­ rous media (siemens et al., 2010), erythromycin adsorption  (sun et al., 2009) and the kinetic interaction with bacterial ribo­ somes (lovmar et al., 2004). the need for and the advantages  of column experiments in the research of organic compounds transport were stressed by banzhaf & hebig (2016). the aim of this pilot study was to: 1) determine the mathe­ matical model of erythromycin migration by means of the deve­ loped algorithm of model selection; 2) estimate the model para­ meters and 3) compare conditions of erythromycin migration in  two different porous media. the authors used the matlab en­ vironment which enables a numerical solution of migration equa­ tions and an estimation of the parameters of the multiparameter models to be determined by means of numerical optimization procedures. the authors expect that the findings of the research  can be further applied to mathematical modelling of erythromy­ cin migration processes in the groundwater environment, inclu­ ding the construction of prognostic models. 2. materials and methods the test of erythromycin migration was conducted in a labora­ tory stand equipped with a filtration column 50 cm in length and  9 cm in diameter. column tests were conducted for two different  porous media. in the first test, the column was filled with spheri­ cal glass granules (70% sio2, 600–800 µm in diameter). the   porous medium was uniformly grained, with the coefficient of  uniformity being u=1.20. the coefficient u is defined as: 60 10 = du d [1] where d10 is the grain diameter [mm] corresponding to 10% of  the sample passing by weight (which means that 10% of the par­ ticles are smaller than the diameter d10) and d60 is the grain di­ ameter [mm] at 60% passing (holtz & kovacs, 1981).  the second experiment included a test using natural sedi­ ment, i.e. a sample of sandur sand from the area of sierosław in  the central wielkopolska region, poland. the investigated sand  (reference si­w1/1) was classified as medium quartz sand, with  a grain uniformity coefficient of u=4.13 (okońska, 2016). this  value means that the sandur sand is less uniform in terms of grain size, compared to the glass granules. the total organic carbon content in the sand determined by the elemental analysis method was 0.114%. the sand sample contained trace amounts of clay.  the clay minerals determined in the soil mineral composition by means of x­ray analysis were vermiculite, kaolinite and illite. distilled water was used to saturate the column with porous material and to prepare solutions containing tracers. during the column test, a sodium chloride solution was injected initially. this substance was  regarded as a conservative  tracer  (ctr)  (leibundgut et al., 2009), i.e. an ideal tracer that undergoes  the advection­dispersion processes. next, a solution containing erythromycin (ery), the migration of which was being investi­ gated, was injected. it was a pulse tracer injection of known con­ centration (fig. 2,a). in the next step – a continuous tracer injec­ tion was performed in accordance with heaviside’s step function  (fig. 2,b), (okońska, 2006). before the erythromycin injection,  the conservative tracer was fully removed from the porous mate­ rial. the concentration of the substance in the injected solution was c0=500 mg·dm­3 for sodium chloride and c0=1541 mg·dm­3 for erythromycin. the presence of erythromycin in the aquatic environment has been widely reported at lower concentrations. however, due to the methodology of the research and the size of  the filtration columns the authors decided to impact the investi­ gated medium with a strong identification signal so as to obtain  a noticeable reaction of the system to that signal (söderstöm  & stoica, 1988). electrolytic conductivity of water was investigated at the  output of the filtration column, using a portable meter hq40d  with a laboratory graphite conductivity electrode intellical.  the values recorded were then converted into tracer concentra­ tions using the previously devised calibration curves. during the tests, the total porosity coefficient n [­] was esti­ mated by means of the weight method and the effective porosity  coefficient ne [­] by means of the volumetric method. water flow  rate q [cm3·s­1] through a soil sample was also recorded. it al­ lowed determination of the hydraulic conductivity k [m·s­1]. the mathematical models describing tracer migration through porous materials neglected chemical and bio­chemical a c0 cin t c0 cout t b a’ b’   lxout tc    0xin tc figure 2, okonska & pietrewicz figure 2. schematic diagram of the column test. explanation: cin(t) injection curve, a pulse injection, b continuous injection, cout(t) breakthrough curve, a’ –  impulse breakthrough curve, b’ continuous breakthrough curve, c0 – tracer concentration in the solution, x – distance, l column length. g eologia c roatica okońska & pietrewicz: identification of a mathematical model and parameter estimation of erythromycin migration in two different porous media, ... 49 reactions, biodegradation, chemo­ and electro­osmotic and capi­ llary effects. moreover, it was assumed that the porous material  cannot be deformed and is fully saturated with liquid solution and all the material and geometrical parameters present in the model are constant. as for the conservative tracer, its transport through the ma­ terial was described with a one­dimensional equation that takes  account of the advection­dispersion processes (a­d model) (we­ ber et al., 1991): 2 2α  ∂ ∂ ∂ = − + + ∂ ∂ ∂  m e e c ki c ki cd t n x n x [2] where c is the tracer concentration in the liquid phase [mg·dm–3], k is the hydraulic conductivity [m·s–1], i is the hydraulic gradient [m·m–1], ne is the effective porosity [–], dm is the diffusion coef­ ficient [m2·s–1], a is the longitudinal dispersivity [m], t is time [s], and x is distance [m]. in the case of erythromycin, the migration mathematical model was identified with impulse breakthrough curve shape in­ dicators (the so­called descriptors) and the authors’ own model se­ lection algorithm. the analysis included the following descriptors: time of maximum tracer concentration at the output tmax [s]: = = max max c c t t [3] where cmax is the maximum tracer concentration at the output [mg·dm–3], spread of the breakthrough curve s [s]: ( ) ( ) ( ) 2 σ ∫ − = ∫ maxt t c t dt c t dt [4] relative tracer recovery e [%]:  ( ) 0 0 100ε = ∫ endt in c t dt c t    [5] where tin is time interval of the tracer injection, when c(t) = c0 at the input [s]. the model selection algorithm takes into account the per­ centage deviations of the descriptors that describe the erythro­ mycin breakthrough curve with respect to descriptors determined  for the conservative tracer breakthrough curve: 100δ − = ⋅ery ctr ctr d d d d    [6] where { }; ;σ ε∈ maxd t , dery is the descriptor value for the break­ through curve of erythromycin, and dctr is the descriptor value for the breakthrough curve of a conservative tracer. seven of the eleven considered sorption models were se­ lected for analysis: •  four simple models, taking account of equilibrium sorption  or non­equilibrium sorption, are described by the follo wing equation (weber et al., 1991): ( ) 2 2 1 ρα  ∂ ∂ ∂ ∂ = − + + − − ∂ ∂ ∂ ∂  s m e e e c ki c ki c sd n t n x n x n t   [7] where the variable s was substituted with an equation describing one of the following sorption models: the henry model (h model),  the freundlich model (f model), the langmuir model (l model),  or the reversible kinetic sorption model (r model);  • three hybrid models that assume the co­occurrence of equilibrium sorption (se) and non­equilibrium sorption  (sn), described by a system of equations (cameron &  klute, 1977): ( ) 2 2 1 ρα   ∂ ∂ ∂ ∂ = − + + − −  ∂ ∂ ∂ ∂    = + s m e e e e n c ki c ki c sd n t n x n x n t s s s   [8] where variables se i sn are substituted with equations describing one of the following models: the henry model with reversible sorption (h­r model) 2 3 =  ∂ = − ∂ e h n n s k c s k c k s t [9] the freundlich model with reversible sorption (f­r model) 2 3  =  ∂ = − ∂ fn e f n n s k c s k c k s t [10] the langmuir model with reversible sorption (l­r model) 2 3 1 α β α  = +  ∂ = − ∂ l l e l n n cs c s k c k s t [11] where rs is the density of the porous medium [kg·dm­3], n is total porosity [­], kh is the henry distribution coefficient [dm3·kg­1], k2 is the first reversible sorption rate coefficient [dm3·kg­1·s­1], k3 is the second reversible sorption rate coefficient [s­1], kf is the freundlich sorption coefficient [dm3·kg­1], nf is the freundlich sorption exponent [­], al is the langmuir constant [dm3·kg­1], and bl is the total sorption capacity of the solid phase [mg·kg­1]. the next stage of the research involved a value identification  (estimation) of transport and sorption parameters in the mat­ lab environment based on the recorded breakthrough curves.  the estimation procedure included: •  numerical  solutions  of  partial  differential  equations  of  transport and sorption assuming suitable boundary condi­ tions, • the application of the numerical optimization method cove­ ring both the global and local optimization procedure (marciniak et al., 2009).  the equations were solved by means of the pdepe solver which utilizes the numerical finite element method (fem). for  identification calculations,  the authors used the optimization toolbox and the in­built lsqcurvefit function for the non­linear solution of the optimization problem. this function, featuring the large-scale optimization option, utilizes the area­restricted search method (coleman & li, 1994). the model was entered into with initial values of the inves­ tigated parameters and with column test data. in the advection­ dispersion model the parameters investigated were the value of hydraulic coefficient k and the value of longitudinal dispersivity a. the subject of identification in sorption models was the sorp­ tion parameters. in those models, the value of the hydraulic coef­ ficient k and the value of longitudinal dispersivity a were substi­ tuted with parameter values determined from the conservative tracer tests. g eo lo gi a c ro at ic a geologia croatica 71/250 searching the point where the error function assumes the smallest value in the search range went on until the set optimiza­ tion criteria were met. while assessing the quality of the fitting  of the theoretical tracer breakthrough curve to the experimental  breakthrough curve the root mean square error rmse and cor­ relation coefficient r were used: ( ) ( ) 2 1 a, =  = − ∑ n m m t m k rmse c t c t [12] where a is the set of estimated parameters, cm is the concentra­ tion value [mg·dm­3] measured in time tm [s], ct is the concentra­ tion value obtained in the simulation [mg·dm­3]; ( )cov , = m t m t c c c c r sd sd [13] where cov signifies the covariance between the values observed  cm [mg·dm­3] and calculated ct [mg·dm­3], and sd is standard deviation. the applied procedure of parameter estimation in the mat­ lab environment was verified by determining the dispersion  parameters in the field programme that uses the analytical so­ lutions of the advection­dispersion model and the optimization method based on the least squares method (maloszewski,  1981; hendry et al., 1999; fohrmann et al., 2001). in this  programme the fitting of the theoretical curve to experimental  data is determined by a model efficiency indicator me [%], where  me = r·100. 3. results the breakthrough curves of the conservative tracer (ctr) and  erythromycin (ery) migration through glass granules are shown  in fig. 3a, and the breakthrough curves of the conservative tracer  and erythromycin migration through sand are shown in fig. 3b. in the second case, the continuous curve for the conservative tracer has not been registered due to the anticipated long time of the column test, which could cause clogging of the deposit. fi­ gure 3 shows erythromycin migration retardation compared to the conservative tracer. in the diagrams, time t of substance mi­ gration through the porous media refers to time t0 that corre­ sponds to distance x [m] and average water flow velocity v [m·s­1]. measured concentration c is presented relative to the injected concentration c0. the value of the hydraulic coefficient k, that was determined in the column test (table 1) and entered into the advection­dis­ persion model as the initial value, in the identification procedure  in the matlab environment changed only within the set meas­ urement error (± 10­15%). as a result of the interpretation of the  experimental breakthrough curve of the conservative tracer, the  following values of longitudinal dispersivity were obtained: a=0.0007 m for the glass medium and a=0.0096 m for sand (ta­ ble 2). figure 4. shows the theoretical conservative tracer break­ through curves calculated in the matlab environment against  the background of experimental points. a very good degree of  breakthrough curve fitting was obtained: the rmse ranging be­ tween 0.014­0.036 and the correlation coefficient r=1 (table 2).  the calculations made in the field programme for impulse  curves confirmed the determined values of the longitudinal dis­ persivity a (0.0009 m and 0.0088 m for glass granules and sand  respectively, for model efficiency 99.8% and 98.9%). figure 3, okonska & pietrewicz 0.0 0.2 0.4 0.6 0.8 1.0 0.0 1.0 2.0 3.0 4.0 c /c 0 [ -] t/t0 [-] ctr ery a 0.0 0.2 0.4 0.6 0.8 1.0 0.0 4.0 8.0 12.0 16.0 20.0 24.0 28.0 c /c 0 [ -] t/t0 [-] ctr ery b figure 3. experimental breakthrough curves of the substance migration through glass granules (a) and sand (b). table 1. a comparison of parameter values recorded in column tests. explanation: * – parameters registered for the conservative tracer impulse curve refer to all curves in this column test. parameter glass granules impulse [continuous] curve sand impulse [continuous*] curve symbol unit value value x m 0.470 0.472 i – 0.015 0.021 ne – 0.36 0.33 q m3·s–1 2.60e-07 [2.38e-07] 1.44e-08 k m·s–1 2.75e-03 [2.51e-03] 1.07e-04 table 2. a comparison of parameter values determined in the matlab environment for the advection-dispersion model. explanation: rmse – root mean square error, r – correlation coefficient, * estimated parameters of the a-d model for the conservative tracer impulse curve have been used as the a-d model parameters for modelling both impulse and continuous curves of erythromycin. model parameter glass granules impulse [continuous] curve sand impulse [continuous*] curve symbol unit value rmse r value rmse r a-d k m·s–1 2.45e-03 [2.31e-03] 0.014 [0.031] 0.999 [1.000] 9.03e-05 0.036 0.997 a m 0.0007 [0.0008] 0.0096 g eologia c roatica okońska & pietrewicz: identification of a mathematical model and parameter estimation of erythromycin migration in two different porous media, ... 51 results obtained for the two different porous media showed  that longitudinal dispersivity differed by an order of magnitude,  despite the same distance covered by the migration tracer. this would imply the dependence of parameter a on the degree of hete­ rogeneity of the porous media (fig. 5a). for the advection­dispersion model it was assumed that the share of molecular diffusion in the conservative tracer migration  through the media is negligible, for glass granules in particular. the parametric analysis of the impact of molecular diffusion co­ efficient dm [m2·s­1] on the result of the calculations of the advec­ figure 4, okonska&pietrewicz 0.0 0.2 0.4 0.6 0.8 1.0 0.0 1.0 2.0 3.0 4.0 c /c 0 [ -] t/t0 [-] data a-d model a 0.0 0.2 0.4 0.6 0.8 1.0 0.0 1.0 2.0 3.0 4.0 c /c 0 [ -] t/t0 [-] data a-d model b figure 4. the theoretical conservative tracer breakthrough curves calculated in the matlab environment, a-d model: glass granules (a) and sand (b). figure 5, okonska & pietrewicz 0.000 0.002 0.004 0.006 0.008 0.010 1.0 2.0 3.0 4.0 5.0 a [m ] u [-] a 0.000 0.002 0.004 0.006 0.008 0.010 0.0e+00 5.0e-09 1.0e-08 a [m ] dm [m2·s-1] glass balls sand b figure 5. the dependence of longitudinal dispersivity a on the uniformity coefficient u (a) and on the molecular diffusion coefficient dm (b). table 3. a comparison of parameter values determined for selected simple and hybrid sorption models depicting erythromycin migration. explanation: symbols are explained in the text; for each curve, the model with the lowest value of the root mean square error rmse and the highest value of correlation coefficient r is in bold. model parameter glass granules sand impulse curve continuous curve impulse curve continuous curve symbol unit value rmse r value rmse r value rmse r value rmse r h kh dm3·kg–1 2.24e-02 0.020 0.993 1.83e-02 0.019 0.999 9.73e-02 0.019 0.910 2.97e-01 0.050 0.930 f kf dm3·kg–1 2.24e-02 0.020 0.993 1.84e-02 0.019 0.999 9.73e-02 0.019 0.910 2.81e-02 0.030 0.974 nf – 1.00 1.00 1.00 2.00 l al dm3·mg–1 3.30e-02 0.019 0.993 2.99e-02 0.022 0.999 9.99e-01 0.007 0.971 9.79e-01 0.074 0.813 bl mg·kg–1 1.00 0.89 0.72 1.00 r k2 dm3·kg–1·s–1 5.22e-04 0.012 0.996 5.20e-04 0.021 0.997 7.35e-06 0.008 0.910 3.07e-06 0.015 0.988 k3 s–1 2.26e-02 2.81e-02 4.27e-05 5.85e-06 h-r kh dm3·kg–1 1.93e-02 0.008 0.998 1.77e-02 0.008 0.999 7.41e-02 0.002 0.992 1.06e-01 0.008 0.997k2 dm3·kg–1·s–1 1.76e-05 1.10e-06 2.24e-06 1.74e-06 k3 s–1 2.72e-03 4.83e-06 1.13e-05 3.70e-06 f-r kf dm3·kg–1 2.23e-02 0.015 0.993 1.77e-02 0.008 0.999 7.41e-02 0.002 0.992 2.00e-02 0.006 0.998 nf – 1.00 1.00 1.00 1.88 k2 dm3·kg–1·s–1 4.48e-06 1.10e-06 2.24e-06 1.00e-06 k3 s–1 1.00e-04 4.83e-06 1.13e-05 2.58e-06 l-r al dm3·mg–1 2.61e-02 0.009 0.998 2.80e-02 0.008 0.999 3.83e-01 0.003 0.988 2.15e-01 0.010 0.995 bl mg·kg–1 1.00 0.89 0.67 1.00 k2 dm3·kg–1·s–1 1.80e-05 1.39e-06 1.79e-06 2.30e-06 k3 s–1 3.12e-03 8.09e-06 7.32e-06 4.53e-06 g eo lo gi a c ro at ic a geologia croatica 71/252 tion­dispersion model showed no changes at the value of hydrau­ lic coefficient k, rmse and r. small changes in the value of the longitudinal dispersivity a were recorded for sand (fig. 5b). mass recovery of erythromycin was 99.1% (± 5%) for the  glass medium, and 96.4% (± 5%) for the sand. on the basis of  calculated deviations of descriptors, according to the identifica­ tion algorithm, three mathematical models were selected for erythromycin and the analysed glass medium for model tests: r, h­r and f­r, and two models were identified for erythromycin  and sand: l and l­r.  the estimation of migration parameters was carried out for the five indicated sorption models plus two simple models: h and  f (table 3). in the case of both porous media the best results were  obtained for hybrid models which combine equilibrium and non­ equilibrium sorption. in three cases, the best fit of theoretical  curves to experimental data was obtained for the henry model  with reversible sorption (h­r model). in the case of sand and the  continuous curve it was the freundlich model with reversible sorption (f­r model). in the process of optimization the exponent  nf=1 was often obtained for the freundlich model. therefore, this equation often became a linear isotherm equation. figure 6. and figure 7. show selected theoretical erythromy­ cin breakthrough curves calculated in the matlab environ­ ment. a very accurate fit of the theoretical curves with experi­ mental data was obtained. in the case of  the h­r model,  the  rmse falls within the range of 0.002­0.008, with a correlation  coefficient r=0.992­0.999 (table 3). it can be assumed that all of  the considered hybrid models characterise erythromycin migra­ tion through the investigated porous media types very well. the value of retardation r, estimated from the relationship t0ery to t0ctr for impulse breakthrough curves, is 1.1 for glass  medium and 1.4 for sand. it implies a low level of sorption inten­ sity of erythromycin (witczak et al., 2013). 4. conclusions the research conducted into erythromycin migration through the two types of porous material resulted in the identification of a  mathematical model for describing antibiotic migration and esti­ mation of the parameters present in the migration model. it can be stated that erythromycin migration is characterised accurately by hybrid models that assume both equilibrium sorption and non­ equilibrium sorption. best results were obtained for the henry  model with reversible sorption, while for the continuous break­ through curve of erythromycin migration through sand – for the freundlich model with reversible sorption. the descriptors and the identification procedure correctly  identified mathematical models for the glass medium. in the case  of natural soils and a higher value of uniformity coefficient, only  the type of sorption ­ reversible or irreversible – can be indicated. the identification algorithm was developed on the basis of sen­ sitivity studies conducted by one of the authors in the past (mar­ ciniak et al., 2013). these studies described the relationship  between the curve’s shape and the parameters of mathematical  models for column tests performed on a uniformly grained po­ rous material. the calculated values of henry distribution coefficients kh from the impulse curve are: 1.93e­02 dm3·kg­1 and 1.77e­02  dm3·kg­1 for the glass medium and 7.41e­02 dm3·kg­1 for the sand. the value of the freundlich sorption coefficient kf determined for sand and erythromycin from the continuous curve is 2.00e­ 02 dm3·kg­1. the freundlich sorption exponent nf equal 1.88 may  indicate, according appelo & postma (1999), “unfavorable  exchange” which means that the fraction in the solution is larger than the fraction adsorbed. the first reversible sorption rate co­ efficient k2 and the second reversible sorption rate coefficient k3 are within the range of 1.76e­05 to 2.24e­06 dm3·kg­1·s­1 and 2.72e­03 to 4.86e­06 s­1 for both porous media. the obtained re­ tardation r values imply a low level of intensity of erythromycin sorption in the case of the investigated porous media (slightly higher for sand). making a comparison of the obtained sorption parameter  values with the results of research conducted by other authors is difficult due to the variation in conditions under which such re­ search was performed. the predicted distribution coefficient  log­ koc for erythromycin is 2.53 dm3·kg­1 (from american chemical society after siemens et al., 2010). the authors received simi­ lar results for sand (logkoc=1.81 dm3·kg­1), converting the henry  figure 6, okonska & pietrewicz 0.0 0.2 0.4 0.6 0.8 1.0 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 c /c 0 [ -] t/t0 [-] data h model h-r model a 0.0 0.2 0.4 0.6 0.8 1.0 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 c /c 0 [ -] t/t0 [-] data h model h-r model b figure 7, okonska & pietrewicz 0.0 0.1 0.2 0.3 0.4 0.5 0.0 1.0 2.0 3.0 4.0 c /c 0 [ -] t/t0 [-] data h model h-r model a 0.0 0.2 0.4 0.6 0.8 1.0 0.0 2.0 4.0 6.0 8.0 c /c 0 [ -] t/t0 [-] data h model f model h-r model f-r model b figure 6. erythromycin theoretical breakthrough curves calculated in the matlab environment for glass granules. figure 7. erythromycin theoretical breakthrough curves calculated in the matlab environment for sand. g eologia c roatica okońska & pietrewicz: identification of a mathematical model and parameter estimation of erythromycin migration in two different porous media, ... 53 distribution coefficient kh from the impulse curve to the norma­ lized distribution coefficient koc with respect to the organic con­ tent  oc  [%]  of  the  solid  matrix:  100 =oc hk k oc [dm3·kg–1]  (appelo & postma, 1999). for glass granules the coefficient  estimated from the impulse curve was: logkoc=0.29 dm3·kg–1. the obtained results (i.e. the identified mathematical models)  confirm the findings made by banzaf & hebig (2016) who  claim that column tests are suitable for determining solute trans­ port as they allow the determination of sorption under dynamic conditions, and they can provide the resulting non­equilibrium reactions. the observed relationships between dispersivity a and the coefficient of uniformity u are consistent with the study of xu & eckstein (1997). the dispersivity value increases with the  heterogeneity of porous media. acknowledgement the results presented in this study were obtained as part of re­ search project no. dec­2011/01/b/st10/02063 financed by the  national science centre resources (poland). references al qarni, h., collier, p., o’keeffe, j. & akunna, j. (2016): investigating the  removal of some pharmaceutical compounds in hospital wastewater treatment plants operating in saudi arabia.- environ. sci. pollut. res., 23/13, 13003­13014.  doi: 10.1007/s11356­016­6389­7 american chemical society. scifinder.- https://scifinder.cas.org/scifinder/, 2009. appelo, c.a.j. & postma, d. (1999): geochemistry, groundwater and pollution. a.a.balkema, rottterdam, brookfield. banzhaf, s. & hebig, k.h. (2016): use of column experiments to investigate the  fate of organic micropollutants - a review.– hydrol. earth syst. sci., 20, 3719– 3737. doi:10.5194/hess­20­3719­2016 and doi:10.5194/hess­20­3719­2016­sup­ plement boleda, m.a., galceran, m.a. & ventura, f. (2011): behaviour of pharma­ ceuticals and drugs of abuse in a drinking water treatment plant (dwtp) using  combined conventional and ultrafiltration and reverse osmosis (uf/ro) treat­ ments.- environ. pollut., 159/6, 1584-1591. doi: 10.1016/j.envpol.2011.02.051 boroń, m. & pawlas, k.  (2015): pharmaceuticals  in aquatic environment –  literature review.- probl. hig. epidemiol., 96/2, 357-363 (in polish). bu, q., wang, b., huang, j., deng, s. & yu, g. (2013): pharmaceuticals and per­ sonal care products in the aquatic environment in china: a review.– j. hazard.  mater., 262, 189–211. doi: 10.1016/j.jhazmat.2013.08.040 cameron, d.r. & klute, a. (1977): convective­dispersive solute transport with a  combined equilibrium and kinetic adsorption model.water resour. res., 13, 183-188. doi: 10.1029/wr013i001p00183 coleman, t.f. & li, y. (1994): on the convergence of reflective newton methods for  large­scale nonlinear minimization subject to bounds.- math. program., 67/2,  189-224. doi: 10.1007/bf01582221 czech, b. (2012): removal of pharmaceuticals from water and sewage by applying  adsorption and photocatalytic methods.- in: ryczkowski, j. (ed.): adsorbents  and catalysts: the technology selected versus the environment. nauka dla gosp­ odarki, 2, 443-452 (in polish). de voogt, p., janex­habibi, m.­l., sacher, f., puijker, l. & mons, m.  (2009): development of a common priority list of pharmaceuticals relevant for the  water cycle.- water sci. technol., 59/1, 39–46. doi: 10.2166/wst.2009.764 fohrmann, g., małoszewski, p. & seiler, k.­p. (2001): experimental deter­ mination of the copper & antimony mobility in calcareous and none­calcareous  aquifer sediments in columns and 1­d reactive transport modeling.- in: seiler,  k.­p. & wohnlich, s. (eds.): new approaches characterizing groundwater  flow. a.a.balkema, lisse, 315-319. hendry, m.j., lawrence, j.r. & maloszewski, p. (1999): effects of velocity  on the transport of two bacteria through saturated sand.- ground water, 37/1,  103-112. doi: 10.1111/j.1745­6584.1999.tb00963.x holtz, r. & kovacs, w. (1981): an introduction to geotechnical engineering.– pren­ tice­hall, new jersey. kümmerer, k. (ed.) (2008): pharmaceuticals in the environment: sources, fate, ef­ fects and risks.– springer­verlag, berlin, heidelberg. leibundgut, c., maloszewski, p. & külls, c. (2009): tracers in hydrology.–  john wiley & sons ltd., chichester. doi: 10.1002/9780470747148 lovmar, m., tenson, t. & ehrenberg, m. (2004): kinetics of macrolide ac­ tion: the josamycin and erythromycin cases.- j. biol. chem., 279/51, 53506­ 53515. doi: 10.1074/jbc.m401625200 ma, y., li, m., wu, m., li, z. & liu, x. (2015): occurrences and regional distribu­ tions of 20 antibiotics in water bodies during groundwater recharge.– sci. total environ., 518–519, 498–506. doi: 10.1016/j.scitotenv.2015.02.100 maloszewski, p. (1981): computerprogramm field für die berechnung der disper­ sion und der effektiven porosität in geschichteten porösen medien.– gsf­bericht  r 269, gesellschaft für strahlen­ und umweltforschung, münchen­neuherberg  (in german). marciniak, m., kaczmarek, m., okońska, m. & kazimierska­drob­ ny, k. (2009): the identification of hydrogeological parameters on the basis of a  numerical simulation of a breakthrough curve and optimization methods.bogu­ cki wyd. nauk., poznań (in polish). marciniak, m., okońska, m., kaczmarek, m. & kazimierska­drob­ ny, k. (2013): the sensitivity test for a breakthrough curve recorded during trac­ er migration in a filtration column.- biuletyn pig, 456, 385-390 (in polish). mompelat, s., le bot, b. & thomas, o. (2009): occurrence and fate of pharma­ ceutical products and by­products, from resource to drinking water.– environ. int.,  35, 803–814. doi:10.1016/j.envint.2008.10.008 okońska, m. (2006): the  identification of pollutants migration parameters  in a  groundwater porous medium by the method of the column experiment modelling. geologos 9, bogucki wyd. nauk., poznań (in polish). okońska, m. (2016): catalog of hydrogeological parameters.– www.hydrometria. amu.edu.pl/badania­naukowe/badania­kolumnowe­migracji zanieczyszczen/, da­ tabase on the website of the department of hydrometry, adam mickiewicz uni­ versity in poznań (in polish). peng, x., ou, w., wang, c., wang, z., huang, q., jin, j. & tan, j. (2014): oc­ currence and ecological potential of pharmaceuticals and personal care products in groundwater and reservoirs in the vicinity of municipal landfills in china.– sci.  total environ., 490, 889-898. doi: 10.1016/j.scitotenv.2014.05.068 siemens, j., huschek, g., walshe, g., siebe, c., kasteel, r., wulf, s.,  clemens, j. & kaupenjohann, m. (2010): transport of pharmaceuticals  in columns of a wastewater­irrigated mexican clay soil.- j. environ. qual., 39/4,  1201–1210. doi: 10.2134/jeq2009.0105 söderström, t. & stoica, p. (1988): systems identification.- prentice­hall, new  jersey. sun, y., zhu, j.­w., chen, k. & xu, j. (2009): modeling erythromycin adsorption  to the macroporous resin sepabead sp825.- chem. eng. comm., 196/8, 906-916.  doi: 10.1080/00986440902743802 watkinson, a.j., murby, e.j. & costanzo, s.d. (2007): removal of antibiotics  in conventional and advanced wastewater treatment: implications for environmen­ tal discharge and wastewater recycling.- water res., 41/18, 4164-4176. doi:  10.1016/j.watres.2007.04.005 watkinson, a.j., murby, e.j., kolpin, d.w. & costanzo, s.d. (2009): the  occurrence of antibiotics in an urban watershed: from wastewater to drinking wa­ ter.- sci. total environ., 407/8, 2711-2723. doi: 10.1016/j.scitotenv.2008.11.059 weber, w.j. jr., mcginley, p.m. & katz, l.e. (1991): sorption phenomena in  subsurface systems: concepts, models and effects on contaminant fate and trans­ port. water res., 25, 499-528. doi:10.1016/0043­1354(91)90125­a witczak, s., kania, j. & kmiecik, e. (2013): catalog of selected physical and  chemical indicators of groundwater pollution and methods of their determination. inspekcja ochrony środowiska, warszawa (in polish). wu, c., huang, x., witter, j.d., spongberg, a.l., wang, k, wang, d. &  liu, j. (2014): occurrence of pharmaceuticals and personal care products and as­ sociated environmental risks in the central and lower yangtze river, china.– eco­ tox. environ. safe., 106, 19-26. doi: 10.1016/j.ecoenv.2014.04.029 xu, m. & eckstein, y. (1997): statistical analysis of the relationships between dis­ persivity and other physical properties of porous media.– hydrogeol. j., 5/4, 4–20.  doi:10.1007/s100400050254 yao, l., wang, y., tong, l., deng, y., li, y., gan, y., guo, w., dong, c.,  duan, y. & zhao, k. (2017): occurrence and risk assessment of antibiotics in  surface water and groundwater from different depths of aquifers: a case study at  jianghan plain,  central china.– ecotox. environ.  safe.,  135,  236–242.  doi:  10.1016/j.ecoenv.2016.10.006 zając, a., zembrzuska, j., budnik, i., kruszelnicka, i. & ginter­kra­ marczyk, d. (2013): pharmaceutical’s path in environment in the area of  wielkopolska - applications, the source of occurrence, threats.– in: production,  economy, management, marketing and environmental protection how it is done in wielkopolska – gniezno, poland, 2013, conference materials. hipolit cegiel­ ski state college of higher education in gniezno, gniezno, 190–205 (in polish). zuccato, e., castiglioni, s., bagnati, r., melis, m. & fanelli, r. (2010):  source, occurrence and fate of antibiotics in the italian aquatic environment.– j. hazard. mater., 179/1–3, 1042-1048. doi: 10.1016/j.jhazmat.2010.03.110 geologia croaticageologia croatica geologia croatica 66/3 191–203 6 figs. 3 tabs. zagreb 2013 the chronology of the šarengrad ii loess-palaeosol section (eastern croatia)  lara wacha*1, 2, lidija galović1, lászló koloszár3, árpád magyari3, 4, géza chikán3 and istván marsi3 1 department of geology, croatian geological survey, sachsova 2, hr-10000 zagreb, croatia; (*corresponding author: lwacha@hgi-cgs.hr) 2 s3 geochronology and isotope hydrology section, leibniz institute for applied geophysics (liag), stilleweg 2, d-30655 hannover, germany 3 geological and geophysical institute of hungary, stefániaút 14, hu-1143 budapest, hungary 4 mol plc, októberhuszonharmadika u. 18, hu-1117 budapest, hungary doi: 10.4154/gc.2013.18 ab stra ct a 23m thick succession of quaternary deposits was investigated at šarengrad, eastern croatia. a geochronological study was performed on loess samples using luminescence dating. an elevated temperature post-ir infrared stimulated luminescence (post-ir irsl) dating protocol was applied. performance tests showed that the protocol is suitable for the samples under study. the post-ir irsl based chronology implies that, contradictory to previous correlations, a middle pleistocene loess-palaeosol sequence is exposed at šarengrad ii and not the last glacial – interglacial cycle. based on ages, the lowermost loess is correlated to oxygen isotope stage (ois) 9-10 and the double palaeosol at the top of the section most likely correlates with ois7. the last glacial record is exposed at the nearby šaren grad i section. furthermore, a heavy and light mineral analysis was performed on the investigated section as well as on the previously investigated šarengrad i section, showing that the mineral association is typical for quaternary deposits of the pannonian basin. keywords: loess-palaeosol, šarengrad, geochronology, luminescence dating, middle pleistocene 1. introduction in croatia (fig. 1a) two major loess regions can be distinguished: the north adriatic loess region related to the river po in northern italy and its tributaries (wacha et al., 2011 a, b; mikulčić pavlaković et al., 2011), and the danube loess region in the eastern part of the country (fig. 1b) (galović et al., 2009, 2011; wacha & frechen, 2011). in eastern croatia, the sedimentary record is more or less continuous, from the neogene to the quaternary, and is related to the sedimentary evolution of the pannonian basin (pavelić, 2001) and influenced by active tectonics during the quaternary (prelogović et al., 1998). the pleistocene sediment succession is closely related to the major rivers of the area (the sava, danube and drava rivers) and their tributaries, and mainly consists of alluvial sediments and thick loess deposits along the danube river. the thickness of loess and loess-like sediments in eastern croatia ranges from 0.5 to 60 m (bognar, 1979). recently, several loesspalaeosol sequences were described and investigated in more detail along the danube river in croatia; the erdut, geologia croatica 66/3geologia croatica 192 (2011) provided a detailed geochronological framework for the gor janović loess section in vukovar, using a newly developed post-ir irsl dating protocol (buylaert et al., 2009, 2012; thiel et al., 2011a,b). in this study, luminescence dating results from the šarengrad ii loess-palaeosol section, (a newly exposed section at the town of šarengrad), are presented and a more robust geochronological framework of the exposed sequence is proposed. for this purpose, the elevated temperature post-ir infrared stimulated luminescence dating protocol, (post-ir irsl), was applied to loess samples (e.g. thiel et al., 2011a, b; wacha & frechen, 2011). furthermore, a com parison with the previously investigated šarengrad i section (galović et al., 2009, 2011) is presented, based on both the geochronological and mineralogical investigations. this study presents a contribution to the unravelling of the loess-palaeosol evolution in eastern croatia, and is also another step forward to establishing a more reliable stratigraphy of loess therein. these results present the first dating attempt of older loess-palaeosol sequences in croatia and therefore can be used to apply high-resolution proxy studies. 2. geological setting and the sediment successions eastern croatia (fig 1b, 2) is mostly covered by quaternary deposits, which were deposited on mesozoic, miocene and pliocene sediments, as well as magmatic and metamorphic rocks. pliocene clastites transgressively overlie middle triassic and miocene sediments. since the end of the miocene, the slow uplift continues in the central part of the fruška gora (gora = mountain). subsidence of its northern and southern slopes has resulted in increased sedimentation during the pliocene and the quaternary (fig. 2). lake and šarengrad and zmajevac sections (galović et al., 2009, 2011; hupuczi et al., 2010; molnár et al., 2010; ba­ nak et al., 2012) and the gorjanović loess section in vukovar (wacha & frechen, 2011). a detailed stratigraphy of the danube loess from the nearby area in vojvodina (serbia) was presented by marković et al. (2012, and references therein). this stratigraphy follows the chinese loess stratigraphic system (kukla, 1987) and is supported by detailed geochronological, palaeomagnetic and other data (marković et al., 2012; fitzsimmons et al., 2012). the first luminescence data for dating the investigated area were presented by singhvi et al. (1989). they applied thermoluminescence (tl) dating to several loess-palaeosol sequences in the carpathian basin, one of which was the erdut section in croatia. based on the ages, singhvi et al. (1989) provided a correlation of loess-palaeosol sequences in the pannonian basin following the pedostratigraphy provided by bronger (1975, 1976), and concluded that the mende-base (mb) soil from the hungarian loess stratigraphy (the f5 palaeosol after bronger, 1975, 1976, 2003), represents the last interglacial, since it is much older than previously assumed. galović et al. (2009), applied the infrared stimulated luminescence (irsl) dating on three loess-palaeosol sequences from eastern croatia; the zmajevac, erdut and šarengrad (referred to as šarengrad i in this study) sec-šarengrad i in this study) secin this study) sections. the age estimates presented in galović et al. (2009) from the loess above the uppermost palaeosol at zmajevac and erdut, are in good agreement with the tl results of singhvi et al. (1989), indicating that most of the investigated loess-palaeosol sections correlate to the last glacial period. galović et al. (2009) measured the feldspar signal from polymineral fine grains, usinga multiple aliquot additive dose (maad) protocol. recently, wacha & frechen figure 1: a, b and c: location maps of the investigated šarengrad ii loess-palaeosol section in eastern croatia and its relationship to the šarengrad i section referred to in this study (https://maps.google.hr/maps?hl=hr&tab=wl). wacha et al.: the chronology of the šarengrad ii loess-palaeosol section (eastern croatia) geologia croatica 193 marsh sediments were deposited during the lower and middle pleis tocene (čičulić-trifunović & galović, 1983, 1985). these sediments were covered by middle and upper pleistocene loess (bognar, 1979). the loess originates from the danube river and its tributaries; there it forms plateaus and covers the slopes of the fruška gora (fig. 2). the vukovar loess plateau continues to the fruška gora.they are separated by the n – s spreading mohovo – bapska – šid fault (čičulić-trifunović & galović, 1983, 1985). the danube river undercuts and erodes the northern slopes, creating steep loess exposures. numerous loess-palaeosol sections have been described in this area (marković et al., 2004, 2006, 2007, 2011; antoine at al., 2009; galović et al., 2009, 2011). the town of šarengrad is located on the danube river, between the towns of vukovar and ilok, in the easternmost part of croatia and the fruška gora to the southeast (fig. 1 a, b, c; 2). the šarengrad i section (45°13’21” n, 19°17’50” e) is situated in a road cut, about one kilometre east of the centre of šarengrad (fig. 1c). the elevation is about 110 m abo ve sea level (a.s.l.). the 16 m thick loess-palaeosol sequence has been described in detail by galović et al. (2009) including a geochronological framework. at the šarengrad i section (fig. 3) the oldest hydromorphic palaeosol contains fe/mnprecipitates. the lowermost loess horizon has a thickness of 140 cm and gave an irsl age estimate of 86.6 ± 8.6 ka (galović et al., 2009). this layer is truncated and covered by laminated sediment with wave-ripple marks in the lower part. the well-developed argillic dark brown palaeosol is characterised by rubification and illuviation processes. the loess on top of that palaeosol is covered by a brown palaeosol. the uppermost palaeosol is weakly developed and covered by loess which is influenced by recent pedogenesis. an irsl age of 55.3 ± 5.5 ka for the uppermost loess can be correlated to the oxygen isotope stage (ois) 3 – 4. however, due to the methodological limitations of the previous study, an older age estimate is not entirely excluded and the data as well as the interpretation should be revised. for a detailed litho stratigraphical subdivision of the profile see galović et al. (2009). the šarengrad ii section (45°13’54’’n, 19°17’50’’e) is located near the main road, at the eastern town exit and about 2 km away from the šarengrad i section. the elevation is about 115 m a.s.l (fig 1c). the base of the investigated šarengrad ii section consists of about 1 m of yellow to light-brown micaceous, finegrained sand, and weakly cemented sand of fluvial origin (figs. 3, 4). the sand fines upwards into a 3 m thick greyish sandy-silty clay, and clay with red hue due to dispersed limonite (fig. 3, 4). this clay is overlain by a greyish, variegated clay with red and brown stripes, and patches caused by enrichment in dispersed limonite and manganese precipitates. the lower part of this horizon is intercalated with a thin layer of carbonate precipitates. the clays represent marshy sediments (hupuczi et al., 2010) and are overlain by greyishyellow clayey silt containing calcareous nodules, which represents a transitional infusion loess layer between swamp deposits and loess. the transition between these two units is gradual. the homogenous, unstratified, slightly micaceous yellow silt, with numerous gastropod remains, covers the marshy sediments and represents the oldest loess, which is the parent material of the overlying 2 m thick palaeosol (figs. 3 and 4). the palaeosol consists of a transitional horizon on the top, an ab-horizon in the middle and a thin c-horizon at the bottom. the ab-horizon is composed of red-brown silty clay and becomes darker with depth. the fossil soil level is strongly compacted, homogenous and unstratified. below the ab-horizon, a 0.2 m thick horizon of carbonate accumufigure 2: geological map of the investigated area with the šarengrad i and ii sections indicated, (modified after čičulić-trifunović & galović,1983). geologia croatica 66/3geologia croatica 194 figure 3: the simplified sketch of the loess-palaeosol sequence of šarengrad i (galović et al., 2009) and the šarengrad ii section. legend: 1. modern soil; 2. loess; 3. transitional layer; 4. ab-horizon; 5. palaeosol; 6. horizontally laminated sediment; 7. wave-ripple marks; 8. silty clay; 9. clay; 10. sand; 11. erosional border; 12. sharp border; 13. transitional border; 14. carbonate concretions; 15. mineralogy sample location. on measuring the cumulative effect of natural radioactivity to which minerals in the sediment were exposed during burial. its basic principle is that the larger the number of trapped electrons or crystal damage in a grain, the longer the time of exposure to natural radiation, and hence the older the material being dated (aitken, 1998). luminescence dating determines the time since mineral grains in the sediment were last exposed to direct sunlight, which removes the latent luminescence signal in minerals (wintle & huntley, 1979). wind induced sediment transportation causes bleaching of the latent luminescence signal in the dosimeters. quartz and feldspar are the two most dominant constituents of loess and both are used as dosimeters for dating. feldspar has the advantage over quartz in that it saturates at higher doses (e.g. at ∼ 2000 gy; thiel et al., 2011c), and hence is more appropriate for dating older sediments. however, feldspar suffers from anomalous fading (wintle, 1973; spooner, 1994), an athermal loss of signal which can cause age underestimation; a major disadvantage when lation and cementation has been recorded. this palaeosol is a chernozem-brown forest type fossil soil, and is covered by a loess horizon about 7 m thick. the loess is well-sorted, homogenous, unstratified, and pale-yellow to greyish-yellow with dark brown manganese dots and white calcareous veins and flakes. it consists of slightlyto medium-micaceous silt. the calcareous nodules are dispersed throughout the entireloess layer, occasionally forming layer-like enrichments. the nodules range in size from 1 to 10 cm. above this thick loess horizon is a double fossil soil, containing two palaeosol subhorizons. it is overlain by a loess layer seen at the uppermost, inaccessible part of the section (figs. 3 and 4). 3. methods and sampling 3.1. luminescence dating luminescence dating is the method of choice for establishing a reliable geochronological framework for loess-palaeosol sequences. it is a radiation exposure dating method, based wacha et al.: the chronology of the šarengrad ii loess-palaeosol section (eastern croatia) geologia croatica 195 using feldspars as dosimeters. a common procedure for overcoming this problem is the application of fading corrections (huntley & lamothe, 2001), after performing fad ing tests (auclair et al., 2003), or measuring more stable luminescence signals (thomsen et al., 2008). hence, in recent years a lot of effort has been invested in studying the properties of more stable feldspar signals obtained at higher temperatures, and the fading properties of feldspar grains (thomsen et al., 2008; buylaert et al., 2009, 2011, 2012; reimann et al., 2011; thiel et al., 2011a, b, c, d; tsukamoto et al., 2012). thomsen et al. (2008) showed that stimulation at elevated temperatures (irsl at 110°c, 170°c and 225°c after an ir bleach at 50°c) reduces the fading rate and gives more stable signals. thiel et al. (2011c) applied a measurement protocol which involved even higher temperatures, (a preheat at 320°c, followed by an ir stimulation at 290°c after an ir bleach at 50°c), showing that there is negligible fading. hence, the elevated temperature post-ir irsl measuring approach is widely accepted as appropriate for the dating of middle pleistocene deposits. 3.1.1. sampling and sample preparation three loess samples were collected from the freshly cleaned loess-palaeosol section exposed in šarengrad ii for luminescence dating using metal cylinders. sample š1 was taken at a depth of 15m, š2 at 10m and š3 at 9m below present day surface. laboratory treatments were performed under subdued red light. the material was treated with hydrochloric acid to remove the carbonates, sodium oxalate against coagulation and hydrogen peroxide to remove organic material. the 4-11 μm fraction was separated from the treated material following frechen et al. (1996). the finegrained aliquots were prepared by dispensing and settling the material onto aluminium discs using acetone. 3.1.2. dose rate determination the u, th and k content were measured by high-resolution gamma spectrometry equipped with a high-purity germanium detector, in the laboratory at the leibniz institute for applied geophysics (liag) in hannover, germany. for the measurements, 700 g of dried and homogenised sample was placed in marinelli-type beakers, sealed and stored for at least four weeks to re-establish the equilibrium between radon and its daughter nuclides prior to measurement. radioactive equilibrium was assumed for the decay chain. cosmic dose rates were corrected for the altitude and sediment thickness following prescott & hutton (1994). the alpha efficiency was estimated to be a mean value of 0.08 ± 0.02 (rees-jones, 1995). the water content was assumed to be 15 ± 5% depending on depth (pécsi, 1990) to allow time dependant changes of the water content. an equipment dependant systematic error of 5% is included for the results of gamma counting.the conversion factors by guerin et al. (2011) were used for dose rate calculations. an error of 10%, which accounts for all uncertainties related to burial figure 4: the šarengrad ii loess-palaeosol section at the town of šarengred. geologia croatica 66/3geologia croatica 196 depth, is assumed for the cosmic dose. the uranium, thorium and potassium concentrations, as well as the cosmic doses and the calculated total dose rates, are given in table 1. 3.1.3. equivalent dose measurements and luminescence characteristics luminescence measurements were performed using an automated risø tl/osl-da15 reader (bøtter-jensen et al., 2000) equipped with a 90sr/90y β-source (delivering∼ 0.094 gy/s to fine-grain material on aluminium discs) at the liag in 2010. infrared light emitting diodes emitting at 875 nm were used for luminescence stimulation, and the luminescence signals were detected in the blue-violet wavelength region (320 – 460 nm) using the schott bg39/corning7-59 filter combination. the equivalent dose (de) is a measure of the past radiation and, when divided by the environmental dose rate, gives the age of the sediment.the de’s were determined using a modified elevated temperature post-ir irsl protocol as proposed by buylaert et al. (2009; coarse grains) and thiel et al. (2011a,b; polymineral fine grains). a similar protocol was applied on the gorjanović loess section in vukovar by wacha & frechen (2011). for the measurements a preheat of 250°c (10 s) was applied followed by ir stimulations at 50°c (ir50) and 225°c (pirir225). the response to the test dose (∼ 50gy) was measured in the same way. a high-temperature signal clean-out at the end of each cycle was not applied because it showed no significant difference during test measurements. the de’s were calculated using the middle part of the decay curve (5-20 s) because previous studies show (e.g. wacha & frechen, 2011; novothny et al., 2010; tsukamoto et al., 2006) that this part of the decay curve showed a lower fading rate than the initial part. the last 50 s of the decay curve were used for background subtraction for the ir50. for the pirir225 the middle 20 s of the curve were used for background subtraction. the intensity of this part of the pirir225 signal curve was similar to the background intensity of the ir50 signal and was therefore selected for subtraction. dose response and decay curves of sample 1662 are presented in figure 5. the signal intensity of the ir50 is significantly stronger than the pirir225 signal (fig. 5a). this could be the result of the dominance of na-feldspars in the polymineral fraction as proposed by tsukamoto et al. (2012). the same was also observed by wacha & frechen (2011) and thiel et al. (2011a). the protocol was tested by checking the recycling ratios, recuperation and by performing the dose recovery tests. the recycling ratios show that the measuring protocol can reproduce the response to a given laboratory dose after it has been repeatedly heated. recycling ratios are 0.99 ± 0.04 (n=3, 1661) and 0.98 ± 0.04 (n=3, 1662) for both the ir50 and the pirir225 signals. for the sample 1663 the recycling ratios are 0.95 ± 0.04 for the ir50 and 0.96 for the pirir225 signal (n=3). recuperation is below 1% for all samples and both signals showing that the signals were reset completely during measurement. the dose recovery test shows the quality of successfully recovering a known laboratory dose (wallinga et al., 2000). for the dose recovery test; six aliquots (sample 1663) were bleached for 4 h in a hönle sol 2 solar simulator. three aliquots were irradiated with a known dose similar to the natural dose, and then measured using the protocol described above. the remaining three aliquots were used to measure residual signals after bleaching. the dose recovery ratio for sample 1663 is 1.5 ± 0.2 and 1.2 ± 0.1 for the ir50 and the pirir225 respectively, showing overestimation especially for the ir50 signal. such poor dose recovery results have been reported in several studies (e.g. thiel et al., 2011d; buylaert et al., 2012), even though the results were in accordance with independent age control data. in the case of buy laert et al. (2012), the dose recoveries showed underestimation for the ir50 signal. furthermore, they compared the results of dose recoveries for the ir50 signals during a single ir stimulation sar protocol and during a post-ir irsl protocol. they concluded that the ir50 de values measured as part of the post-ir irsl protocol could underestimate the irsl signal of the single ir stimulation sar protocol which uses lower preheat conditions. furthermore, they concluded that a poor dose recovery ratio is not a good predictor of inaccurate de measurement and that the dose recovery should only be used as a qualitative indicator of the performance of sar (buylaert et al., 2012). for comparison, in this study, a dose recovery test was performed with a single ir stimulation sar protocol while using various preheat temperatures (sample 1661). the dose recovery ratios were all ∼ 1.0 which seems to be satisfactory (data not shown). another reason for poor dose recovery results could be the size of the test dose applied for the measurements (∼ 50 gy) which might be too small. qin & zhou (2012) showed that measured de-s decrease by ∼ 6% with the test dose increasing from 12 gy to 60 gy, while an increase is observed when the test dose is further increased (measured for the pirirsl295 signal). this could be the result of de overestimation due to a thermally transferred post-irirsl295 signal and hence poor dose recoveries (qin & zhou, 2012). table 1: dosimetry results. the total dose rate is the sum of alpha, beta, gamma and cosmic radiation. sample name sample id (lum no) depth below surface (m) u (ppm) th (ppm) k (%) cosmic dose rate (mgy/a) total doserate (mgy/a) š1 1661 15 2.79 ± 0.03 11.66 ± 0.07 1.34 ± 0.02 0.030 ± 0.003 3.18 ± 0.19 š2 1662 10 3.04 ± 0.04 12.44 ± 0.11 1.61 ± 0.02 0.049 ± 0.005 3.59 ± 0.21 š3 1663 9 2.94 ± 0.02 11.84 ± 0.06 1.53 ± 0.01 0.055 ± 0.006 3.43 ± 0.20 wacha et al.: the chronology of the šarengrad ii loess-palaeosol section (eastern croatia) geologia croatica 197 figure 5: luminescence characteristics of the measured irsl signals of sample 1662. a) signal intensity (decay curves) and b) dose response curves with indicated de values for both the ir50 and pirir225 signals. dose response curves were fitted using exponential and linear curve fitting. nevertheless, we acknowledge that we are unsure of the significance of our overestimated dose recovery results. sohbati et al. (2011) showed that residual doses appear to be dependant on the corresponding natural doses; the larger the natural dose, the larger the residual. they also showed that there may be a small, apparently unbleachable component present. our measured residual doses (∼ 2gy for ir50 and ∼ 6gy for pirir225) are negligible and do not influence the quality of the dose recoveries nor the de-s. 3.1.4. fading tests and fading corrections in this study fading tests and fading corrections were performed following auclair et al. (2003) and huntley & lamothe (2001), respectively. according to huntley & lamothe (2001), fading corrections are applicable only for the linear part of the growth curve i.e. for samples up to 50 ka. buylaert et al. (2011) applied fading corrections on k-feldspars from a mis5e site in denmark for which independent age control was available and concluded that fading corrected irsl ages using k-feldspar may be both precise and accurate over a greater age range than proposed by huntley & lamothe (2001). in this study fading tests were performed for both ir50 and pirir225 signals and fading corrections were applied for the ir50 signal. fading tests were performed on the same aliquots as for the de measurements. the aliquots were irradiated with a beta-dose similar to the natural de, and then measured using the above mentioned protocol, but with inserted different storage times, up to ∼10 hours, immediately after irradiation and preheat (auclair et al., 2003). the fading rates (g-values) were normalised to a measurement time delay of 2 days after irradiation. the mean g-values calculated from three aliquots per sample and their standard errors were used for fading corrections. the g-values are 5.0 ± 0.3, 3.9 ± 0.4 and 4.4 ± 0.3 for the ir50 and 1.4 ± 0.7, 0.3 ± 1.0 and 1.8 ± 0.7 for pirir225 signals, for samples š1, š2 and š3 respectively. the results of the fading tests are presented in table 2. 3.2. heavy and light mineral analysis of loess samples the samples for the modal analyses of loess were collected at the same depths as the samples for luminescence dating. for correlation and comparison between the sections, three samples were also analysed from the šarengrad i section. in addition to samples from the location for luminescence dating, one further sample was collected from the middle loess layer (fig. 3). to determine the qualitative and semi-quantitative mineral composition of heavy and light mineral associations, the samples were extracted after disaggregation in an ultrasound bath and sieved to the 0.09–0.16 mm size fraction, followed by dissolution of calcite with hydrochloric acid (5%). this fraction was selected for the analysis, because it includes all virtual mineral species in proportions representative of the bulk sample. the heavy mineral fraction (hmf) was separated from the light mineral fraction (lmf) using bromoform (chbr3) at a density of 2.85-2.88 gcm–3. canada balsam was used as the mounting medium, and the slides of heavy and light mineral fractions were examined in polarized light (mange & maurer, 1992). qualitative and semi-quantitative composition of each sample was established after the determination of 300–400 grains and the percentage of each mineral was calculated. the composition of transparent minerals was presented in ranges in the case of less than 1% of hmf per sample due to the lack of grains required for calculating the reliable semi-quantitative mineral composition. 4. results and discussion 4.1. the chronology of the middle pleistocene loess section šarengrad ii the dose rates are 3.18 ± 0.19, 3.59 ± 0.21 and 3.43 ± 0.20 mgy/a of samples š1, š2 and š3 (table 1), respectively, which is in accordance with other loess in croatia (wacha et al., 2011a, b; wacha & frechen, 2011; galović et al., 2009) and european loess (e.g. frechen et al., 1997; novothny et al., 2011; thiel et al., 2011c, in press). geologia croatica 66/3geologia croatica 198 the complete age dataset obtained is presented in table 2. the de values are in stratigraphic order. the measured residuals were ~ 2gy for the ir50 signal and ~ 6gy for the pirir225 signal which is negligible and was hence not subtracted from the de’s and did not play an important role in the results of the dose recovery test. the somewhat high dose recovery ratios were not considered to be inadequate; therefore the de results were not discarded. the ratio of the sensitivity-corrected natural signal to the laboratory saturation level was checked. according to wintle & murray (2006), reliable equivalent doses for quartz osl can be obtained up to a dose value of 2d0 which corresponds to 86% saturation. the same principle was applied to evaluate the d0 values of our dose response curves. the values of 0.79 ± 0.08, 0.76 ± 0.07 and 0.77 ± 0.10 for the ir50 signal curve and the values of 0.86 ± 0.04, 0.82 ± 0.05 and 0.81 ± 0.05 for the pirir225 signal for samples š1, š2 and š3, respectively, were calculated. our data show that the de values obtained for the ir50 are less than 2d0, while the de values for the pirir225 signal are a little higher than d0 for š1 sample, equal to the 2d0 for š2 sample and less than 2d0 for š3 sample indicating that the samples are very close to saturation, or in the case of sample š1 at saturation. the g-values are given in table 2 where it can be seen that the highest fading rate measured for the ir50 signal is 5.0 ± 0.3%/decade (sample š1). for the pirir225 signal the highest value calculated was 1.8 ± 0.7 %/decade (sample š3) showing that fading for the pirir225 signal indeed is significantly lower than from the ir50 signal. these values are similar to other data from the area e.g. from the gorjanović loess section in vukovar (e.g. wacha & frechen, 2011) where the same protocols and conditions were used for data calculations. furthermore, they calculated data using different integration limits to find the most stable part of the curve with the lowest fading. they noticed that the lowest fading can be seen in the middle part of the curve. their observations were applied in this study. fading corrections using the method by huntley & lamothe (2001) were applied for the ir50 signal. it has been shown that pirir225 signals show lower to negligible fading, and that measured g-values might not be representative for the fading rates over geological time (e.g. thiel et al., 2011b). even though we measured g-values of up to 2%/decade for our samples, we did not apply any fading correction, but acknowledge that this may result in an underestimate of the age. the results of the fading corrected ir50 and the pirir225 are in very good agreement within the uncertainties (table 2). the first detailed investigation of loess exposures at the town of šarengrad were presented by galović et al. (2009), where a geochronological framework of the šarengrad i section was presented based on luminescence dating. the ages were calculated using the maad protocol, which in a way, is an outdated protocol. the irsl ages of 55.3 ± 5.5 ka and 86.6 ± 8.6 ka can be correlated to the last glacial – last interglacial period, but it is probable that the ages show some underestimation due to the lack of fading corrections on the samples. more measurements using up-to-date measurement protocols are mandatory to re-evaluate the existing data. the presented chronology of the šarengrad ii section, which is in the vicinity of the šarengrad i section (fig 1c), is based on the pirir225 data (fig. 6) and is considered to represent minimum ages due to the measured g-values of around 2%/ decade (table 2) and the signal being close to saturation. furthermore, the results were correlated, (in addition to the older šarengrad i section), with other loess sections in the area (galović et al., 2009; wacha & frechen, 2011; thiel et al., in press), which has allowed compilation of a chronostratigraphy of the area based on numerical dating. at the bottom of the šarengrad ii section, sand and clay horizons are exposed (fig. 3, 4, 6). these deposits were already registered as being widespread in this area in the base of loess by gorjanović kramberger (1922), who conducted the first detailed investigation on loess deposits covering the sand. furthermore, he made a detailed investigation of the steep outcrop at the bank of the danube at šarengrad, where he described a 2.5 m thick loess package covering yellow and grey sands and sandstones. based on viviparidae remains observed in the sands, he assumed that the sediment was deposited as early as the late pliocene or later (gorjanović kramberger, 1922). poje (1986) produced a detailed palaeoclimatic reconstruction of the vukovar loess plateau based on detailed malacological investigations. in her study, among others, a loess section at šarengrad (the exact location was not indicated),was described consisting of three loess layers intercalated with two palaeosols. the mollusc assemblages investigated there indicated cold climatic conditions; comparison with mollusc data and radiocarbon ages from carbonate concretions found in loess at the section at vukovar (galović & mutić, 1984) led to correlation with the last glacial (poje, 1986). hupuczi et al. (2010) table 2: summary of the ir50 and pirir225 results (3 aliquots per sample). fading-corrected ages for the ir50 signal were calculated after huntley & lamothe (2001). sample depth below surface (m) de (gy) g-value (%/decade) uncorrected age (ka) fading corrected age (ka) ir50 pirir225 ir50 pirir225 ir50 pirir225 ir50 š1 (1661) 15 598.4 ± 48.8 946.5 ± 51.2 5.0 ± 0.3 1.4 ± 0.7 188 ± 19 298 ± 24 324 ± 36 š2 (1662) 10 548.7 ± 29.6 816.9 ± 49.5 3.9 ± 0.4 0.3 ± 1.0 153 ± 12 228 ± 19 228 ± 21 š3 (1663) 9 539.8 ± 42.3 788.6 ± 43.0 4.4 ± 0.3 1.8 ± 0.7 157 ± 15 230 ± 18 250 ± 26 wacha et al.: the chronology of the šarengrad ii loess-palaeosol section (eastern croatia) geologia croatica 199 performed malacological investigations at the šarengrad ii section, where they separated five malacological horizons. based on their results and the correlation with data from the šarengrad i section (galović et al., 2009), they assumed a last glacial-interglacial age for the section. they also provided palaeoenvironmental reconstructions based on their mollusc assemblages. for the sand and clay layers from the bottom of the šarengrad ii section, they recognized a freshwater environment with warm climatic conditions (hupuczi et al., 2010), which grades into a fluvial setting and was eventually covered by loess representing cold climatic conditions. based on the results of irsl dating applied in this study, the loess package covering the sand and clay gave a pirir225 age estimate of 298 ± 24 ka which (if the fading corrected ir50 age estimate of 324 ± 36 ka is considered), correlates well with the end of the oxygen isotope stage (ois) 10 and the beginning of ois9 (e.g. litt et al., 2008). the upper loess package showed pirir225 ages of 228 ± 19 ka and 230 ± 18 ka; this correlates with ois8. this loess package is covered by a double palaeosol and another loess layer. based on our results we conclude that the double palaeosol correlates to ois7, but more dating is necessary for providing further evidence for such a statement. similar double palaeosols were described in the vojvodina region and in hungary. thiel et al. (in press) applied the post-ir irsl to the paks loess section in hungary. in the upper part of the section, a soil complex is exposed, (the so called bd1-bd2 complex – see thiel et al., in press). the luminescence ages from above this soil complex pointed to ois6, and thus the bd soil complex correlates to ois7. the loess below the soil complex can be correlated to ois8 based on the data presented by thiel et al. (in press). the same interpretation, based on magnetic susceptibility measurements and a detailed lithostratigraphy, but unfortunately lacking numerical age estimates, from the udvari-2a borehole from hungary was presented by koloszar & marsi (2010) and koloszar (2010). marković et al. (2011) correlated the double soil complex (the v-s2 soil from the serbian stratigraphy; the bd1-bd2 soil complex from hungary), with the double peak of ois7. recently, dating of the middle pleistocene loess from stari slankamen was performed (murray et al., in press), using an elevated temperature post-ir irsl dating protocol. they suggested that the loess unit v-l2 accumulated during ois6 and that the v-s1 pedocomplex can be correlated with the complete ois5 stage. they also proposed minimum ages of ~230 ka for the loess unit v-l3 (ois8) and palaeosols v-s3, v-s4 and v-s5 exposed at stari slankamen. this interpretation is supported by magnetostratigraphic and aminostratigraphic evidence (marković et al., 2011). these observations are in very good agreement with our study; however, more sampling of the uppermost loess horizon is necessary to clarify whether both soils belong to ois 7. we conclude that ois7 is represented by a double palaeosol complex in the wider region (the pannonian basin). figure 6: luminescence dating results and interpretation of the data from the šarengrad ii section. fading corrected ir50 and pirir225 results are presented for comparison as well as the correlation to oxygen isotope stages (litt et al., 2008). the lowermost sample (š1) shows signals which are very close to saturation and should hence be considered as minimum age. geologia croatica 66/3geologia croatica 200 our results suggest the conclusion that loess accumulation in this area started during the antepenultimate glacial, or even earlier. based on the data from galović et al. (2009), it can be concluded that it was also deposited during the last glacial, although these data should be interpreted with caution. the data of the šarengrad i section should be re-evaluated using modern dating techniques to confirm such premises. in the investigated area, loess deposition was interrupted by pedogenesis at least six times. based on the development stages of the palaeosol types and their chronology, šarengrad i and ii cannot be correlated. nevertheless, the two lowermost palaeosols at šarengrad i (the hydromorphic and the well-developed argillic dark brown palaeosol with rubification – galović et al., 2009), indicate at least two intensive and relatively longer periods of warmer climate. various palaeosols exposed at the studied sections are related to interglacial and/or interstadial conditions and provide evidence of abrupt climate changes. 4.2. mineralogical data and the provenance of the material the bulk mineral composition of tmf of all investigated samples is typical for loess-palaeosol sequences of the area (mutić 1993; banak et al., 2012; thamó-bozsó et al., in press).there is a significant difference in the light mineral fraction between the studied sections. the dominant constituent of the light mineral fraction of the šarengrad ii sam-šarengrad ii samsamples is quartz (21 – 76%) while in the šarengrad i samples muscovite (2 72%) predominates; followed by feldspars (<18%). lithic fragments are present in all samples (< 7%). the amount of heavy minerals ranges from < 1% in sample š3 to 6% in sample š-22. among them the transparent heavy minerals predominate (23–67%) over opaque minerals (13– 51%). biotite and chlorite are present in all samples, but they are more abundant in the samples from the šarengrad i sec-šarengrad i secsection. the most abundant transparent heavy minerals are resistant garnet grains (32 – 44%) followed by epidote (18– 26%). less abundant are amphiboles (2 – 16%). pyroxenes, kyanite, staurolite, tourmaline, zircon, rutile and titanite occur regularly. chromite is present in all samples except š2 and š3 from the šarengrad ii section. the results of the mo-šarengrad ii section. the results of the mosection. the results of the modal analysis are presented in table 3. thamó-bozsó et al. (in press, fig. 4) showed that nnw winds could supply the wider transdanubian area, and hence eastern croatia, with aeolian material of such mineral composition. the chloriteand/or biotite-rich heavy mineral association of loess from south-transdanubia is similar to the composition of recent fluvial sediments of the danube and other transdanubian rivers (thamó-bozsó et al., in press), and they could also be the source area for (re)sedimentation. alternatively, the base of the šarengrad ii sec-šarengrad ii sec-sectionis composed of fine-grained micaceous fluvial sand (see section 4 above; figs. 3, 4), which probably extends over a wider area, and could also be the local source of the material. chlorite and biotite are flaky minerals, together with muscovite which is the dominant mineral in the samples from the šarengrad i section, and their behaviour is very similar during transport (alluvial or aeolian). due to the higher mobility of flaky minerals, (greater than that of the isometric or elongated ones), it is very likely that they were transported farther and from a more distal source (thamó-bozsó et al. (in press). domination of flaky minerals is observed in several horizons in the zmajevac, erdut and šarengrad i sec-šarengrad i secsections which correlate to the last glacial period (galović et al., 2009) and in fluvial micaceous fine grained sand in the base of loess in the area (macroscopically determined at šarengrad ii and the ilok sandpit). the predominance of garnet and epidote indicate the danube flood plain region to be the main source of the material (thamó-bozsó & kovács, 2007), and loess from hungary (thamó-bozsó et al., in press). the amphiboles, could also originate from the nearby slavonian mountains and/or from the dinaride ophiolite zone in bosnia in addition to the danube flood plain (pamić et al., 2002; robertson et al., 2009). chromite is present in all samtable 3: modal composition of the heavy and light mineral fractions (0.09–0.16 mm) of loess horizons from the šarengrad i and ii sections. lmf – light mineral fraction, q – quartz, m – muscovite, f – feldspar, lf – lithic fragments; hmf – heavy mineral fraction, op – opaque minerals, ch – chlorite; b – biotite, thm – transparent heavy minerals; ep-zt – epidote – zoisite, am – amphibole, py – pyroxene, g – garnet, ky – kyanite, st – staurolite, tu – tourmaline, zr – zircon, rt – rutile, ti – titanite, ap – apatite, chr – chromite. sample lmf % of hmf hmf transparent heavy minerals q m f lf op ch b thm ep am py g ky st tu zr rt ti ap chr zt šarengrad i š-1 21 72 2 4 5 13 43 16 28 26 16 5 34 1 2 2 3 3 5 1 1 š-12 35 61 2 1 3 15 35 15 35 25 9 2 33 5 4 2 3 6 5 0 6 š-22 47 40 11 2 6 51 24 3 23 18 14 3 33 3 5 3 2 1 7 3 7 šarengrad ii                                           š1 58 27 8 7 5 25 9 6 65 26 12 9 32 1 4 2 2 5 3 0 5 š2 52 30 14 4 5 17 7 2 67 22 2 6 43 2 3 7 2 9 2 3 0 š3 76 2 18 3 < 1 14 1 1 61 22 4 9 44 1 3 3 2 9 1 1 0 wacha et al.: the chronology of the šarengrad ii loess-palaeosol section (eastern croatia) geologia croatica 201 ples except š2 and š3 from the šarengrad ii section and in-šarengrad ii section and insection and indicates an ultramafic magmatic source, most probably the dinaride ophiolite zone, eroded and transported by the vrbas and bosnia rivers in the south to the pannonian basin in the north. this is supported by simulations of palaeowind patterns in the carpathian basin during the last glacial period proposed by újvári et al. (2010), showing west-southwesterly (wsw) wind directions. in general, such a heavy mineral association as presented here is similar to the danube flood plain sediments (thamó-bozsó & kovács, 2007) and loess from hungary (thamó-bozsó et al., in press), but the southern edge of the carpathian basin was probably influenced by the nearby dinaride ophiolite zone which makes a slight contribution to the difference in the mineral composition. 5. conclusion at the šarengrad ii section, an excellent transition from sediments deposited in a waterlain marshy environment, to sediments deposited under subaerial conditions is exposed. an elevated temperature post-ir irsl protocol was applied on polymineral fine-grains separated from loess from the šarengrad ii section for equivalent dose (de) estimation. this method proved to be applicable for our samples. our interpretation is based on the pirir225 signal, even though the doses were near saturation and fading around 2%/decade was measured for the samples.the dating results from the šarengrad ii section indicate ages much older than the last glacial-last interglacial cycle, discarding previous interpretations; clearly, the section is of middle pleistocene age. the lowermost loess can be correlated with oxygen isotope stage (ois) 9-10, and the lowermost palaeosol can be correlated to ois9. due to the measured fading of the pirir225 signal, an even older age cannot be entirely excluded. the middle loess section can be correlated to ois8 and the double palaeosol to ois7. similar penultimate interglacial double palaeosols have commonly been described in the european loess stratigraphy (the bd1-bd2 palaeosol from hungary and the v-s2 from serbia). the šarengrad ii succession, together with the nearby šarengrad i section, reflect environmental changes since at least ois 10 and can be correlated to the last three glacial-interglacial cycles. the penultimate and last glacial loess exposed at šarengrad is intercalated with at least six palaeosols. our study is the first to date older (antepenultimate glacial) loess in croatia. acknowledgement this work is a result of the bilateral croatian-hungarian project financed by the intergovernmental tét foundation (cro-16/2008), the croatian ministry of science, education and sports (project nr. 18118110961093) and the daad (german academic exchange service – a/07/90559). lw would like to thank prof. dr. manfred frechen and dr. sc. sumiko tsukamoto for help and advice. very special thanks to dr. sc. christine thiel and dr. sc. edit thamó-bozsó for their thorough reviews which significantly improved the manuscript. references aitken, m.j. (1998): an introduction to optical dating. the dating of quaternary sediments by the use of photon-stimulated luminescence.– oxford university press, 267 p. antoine, p., rousseau, d.d., fuchs, m., hatté, c., gauthier, c., marković, s.b., jovanović, m., gaudenyi, t., moine, o. & rossignol, j. (2009): high-resolution record of the last climatic cycle in the southern carpathian basin (surduk, vojvodina, serbia).– quatern. int., 198, 19–36. auclair, m., lamothe, m. & huot, s. (2003): measurement of anomalous fading for feldspar irsl using sar.– radiat. meas., 37, 487–492. banak, a., mandic, o., kovačić, m. & pavelić, d. (2012): late pleistocene climate history of the baranja loess plateau – evidence from the zmajevac loess-paleosol section (northeastern croatia).– geol. croat., 65/3, 411–422. bognar, a. (1979): distribution, properties and types of loess and loess-like sediments in croatia. – acta geol. acad. sci. hung., 22, 267–286. bøtter-jensen, l., bulur, e., duller, g.a.t. & murray, a.s. (2000): advances in luminescence instrument systems.– radiat.meas., 32, 523–528. bronger, a. (1975): paläeoböden als klimazeugen – dargestellt an löss-boden-abfolgen des karpatenbeckens.– quat. sci. journ (e & g), 26, 131–154. bronger, a. (1976): zur quartären klimaund landschaftsentwicklung des karpatenbeckens auf (palaeo)-pedologischer und bodengeographischer grundlage.– kieler geogr.schr., 45, p. 268. bronger, a. (2003): correlation of loess-paleosol sequences in east and central asia with se central europe: towards a continental quaternary pedostratigraphy and paleoclimatic history.– quatern. int., 106/107, 11–31. buylaert, j.p., murray, a.s., thomsen, k.j. & jain, m. (2009): testing the potential of an elevated temperature irsl signal from k-feldspar.– radiat. meas., 44, 560–565. buylaert, j.p., huot, s., murray, a.s. & van den haute, p. (2011): infrared stimulated luminescence dating of an eemian (mis 5e) site in denmark using k-feldspar.– boreas, 40/1, 45–56. buylaert, j.p., jain, m., murray, a.s., thomsen, k.j., thiel, c. & sohbati, r. (2012): a robust feldspar luminescence dating method for middle and late pleistocene sediments.– boreas, 41/3, 435–451. čičulić-trifunović, s. & galović, i. (1983): osnovna geološka karta sfrj 1:100.000 list bačka palanka l 34–99 [basic geological map of sfry 1:100000, bačka palanka sheet – in croatian]– geološki institut beograd i geološki zavod zagreb, savezni geološki zavod, beograd. čičulić-trifunović, s. &galović, i.(1985):tumač ogk 1:100.000 list bačka palanka l 34-99[basic geological map of sfry 1:100000, geology of the bačkapalanka sheet – in croatian].– geološki institut beograd i geološki zavod zagreb, savezni geološki zavod, beograd, 46p. fitzsimmons, k.e., marković, s.b. & hambach, u. (2012): pleistocene environmental dynamics recorded in the loess of the middle and lower danube basin.– quaternary sci. rev.,41, 104–118. frechen, m., schweitzer, u. & zander, a. (1996): improvements in sample preparation for the fine grain technique.– ancient tl, 14/2, 15–17. frechen, m., horváth, e. & gábris, g. (1997): geochronology of middle and upper pleistocene loess sections in hungary.– quaternary res., 48/3, 291–312. geologia croatica 66/3geologia croatica 202 galović, l., frechen, m., halamić, j., durn, g. & romić, m. (2009): loess chronostratigraphy in eastern croatia – a first luminescence dating approach.– quatern. int., 198, 85–97. galović, l., frechen, m., peh, z., durn, g. & halamić, j. (2011): loess/palaeosol section in šarengrad, croatia – a qualitative discussion on the correlation of the geochemical and magnetic susceptibility data.– quatern. int., 240, 22–34. galović, i. & mutić, r. (1984): gornjopleistocenski sediment istočne slavonije (hrvatska) [upper pleistocene sediments of eastern slavonia (croatia)].– rad jazu, 411, 299–356, zagreb. gorjanović kramberger, d. (1922): morfologijske i hidrografijske prilike prapornih predjela srijema, te pograničnih česti žu pani je virovitičke [morphologic and hydrographic conditions of loess areas in srijem].– glasnik hrvatskoga prirodoslovnog društva, xxxiv, 111–164, zagreb. guérin, g., mercier, n. & adamiec, g. (2011): dose-rate conversion factors: update.– ancient tl, 29/1, 5–8. huntley, d.j. & lamothe, m. (2001): ubiquity of anomalous fading in k-feldspars, and the measurement and correction for it in optical dating.– can. j. earth. sci., 38, 1093–1106. hupuczi, j., molnár, d., galović, l. & sümegi, p. (2010): preliminary malacological investigation of the loess profile at šarengrad, croatia.– centr. eur. j. geosci., 2/1, 57–63. koloszár, l. (2010): the thickest and the most complete loess sequence in the carpathian basin: the borehole udvari-2a.– centr. eur. j. geosci., 2/2, 165–174. koloszár l. & marsi i. (2010): a kárpát-medence legvastagab b és tegteljesebb löszrétegsora: az udvari–2a fúrás szelvénye és kvarter rétegtani jelentősége [the thickest and the most complete loess sequence in the carpathian basin: the section of the borehole udvari-2a and its significance in the quaternary stratigraphy].– földtani közlöny, 140/3, 251–262. kukla, g. (1987): loess stratigraphy in central china.– quaternary sci. rev., 6, 191–219. litt, t., schminke, h.-u., frechen, m., schlüchter, c. (2008): quaternary.– in: mccann, t. (ed.): the geology of central europe: mesozoic and cenozoic. geological society of london, 1287–1340. mange, m., a., & maurer, h. f. w., (1992): heavy minerals in colour.– chapman and hall, london, 147p. marković, s.b., kostić, n.s. & oches, e.a. (2004): palaeosols in the ruma loess section (vojvodina, serbia).– rev. mex. cienc. geol., 21, 79–87. marković, s.b., oches, e., sümegi, p., jovanović, m. & gaudenyi, t. (2006): an introduction to the middle and upper pleistocene loess-palaeosol sequence at ruma brickyard, vojvodina, serbia.– quatern. int., 149, 80–86. marković, s.b., oches, e.a., mccoy, w.d., frechen, m. & gaudenyi, t. (2007): malacological and sedimentological evidence for ‘‘warm’’ glacial climate from the irig loess sequence, vojvodina, serbia.– geochem. geophy.geosy., 8/9, q09008. marković, s.b., hambach, u., stevens, t., kukla, g.j., heller, f., mccoy, w.d., oches, e.a., buggle, b. & zöller, l. (2011): the last million years recorded at the stari slankamen (northern serbia) loess-palaeosol sequence: revised chronostratigraphy and long-term environmental trends.– quaternary sci. rev., 30, 1142–1154. marković, s.b., hambach, u., stevens, t., jovanović, m., o’hara-dhand, k., basarin, b., lu, h., smalley, i., buggle, b., zech, m., svirčev, z., sümegi, p., milojković, n. & zöller, l. (2012): loess in the vojvodina region (northern serbia): an essential link between european and asian pleistocene environments.– neth. j.geosci., 91, 1/2 173–188. mikulčić pavlaković, s., crnjaković, m., tibljaš, d., šoufek, m., wacha, l., frechen, m. & lacković, d. (2011): mineralogical and geochemical characteristics of quaternary sediments from the island of susak (northern adriatic, croatia).– quatern. int., 234, 32–49. molnár, d., hupuczi, j., galović, l. & sümegi, p. (2010): preliminary malacological investigation on the loess profile at zmajevac, croatia.– centr. eur. j. geosci., 2/1, 52–56. murray, a.s., schmidt, e.d., stevens, t., buylaert, j.p., marković, s.b., tsukamoto, s. & frechen, m. (in press): dating middle pleistocene loess from stari slankamen (vojvodina, serbia) – limitations imposed by the saturation behaviour of an elevated temperature irsl signal. – catena; http://dx.doi. org/10.1016/j.catena.2013.06.029 mutić, r. (1993): korelacija kvartara istočne slavonije na osnovi podataka mineraloško-petrografskih analiza (istočna hrvatska). dio iii: slavonsko-srijemska potolina [correlation of the eastern slavonian quaternary deposits based onthe mineralogical and petrological analyses (eastern croatia). part iii: the slavonija-srijem depression].– acta geologica, 23/1, 1–37. novothny, á., frechen, m., horváth, e., krbetschek, m. & tsukamoto, s. (2010): infrared stimulated luminescence and radiofluorescence dating of aeolian sediments from hungary.– quat. geochronol., 5, 114–119. novothny, á., frechen, m., horváth, e., wacha, l. & rolf, ch. (2011): investigating the penultimate and last glacial cycles of the süttő loess section (hungary) using luminescence dating, high resolution grain size, and magnetic susceptibility data.– quatern. int., 234/1–2, 75–85. pamić, j., tomljenović, b. & balen, d., (2002): geodynamic and petrogenetic evolution of alpine ophiolites from the central and nw dinarides: an overview.– lithos, 65, 113–142. pavelić, d. (2001): tectonostratigraphic model for the north bosnian sector of the miocene pannonian basin system – basin. res., 12, 359–376. pécsi, m. (1990): loess is not just the accumulation of dust.– quatern. int., 7/8, 1–21. poje, (1986): ekološke promjenena vukovarskom prapornom ravnjaku proteklih cca 500.000 godina [ecological changes on the vukovar loess plateau during the last 500 000 years – in croatian].– geol. vjesnik, 39, 19–42. prelogović, e., saftić, b., kuk, v., velić, j., dragaš, m. & lučić, d. (1998): tectonic activity in the croatian part of the pannonian basin.– tectonophysics, 297, 283–293. prescott, j.r. & hutton, j.t. (1994): cosmic ray contributions to dose rates for luminescence and esr dating: large depths and longterm time variations.– radiat. meas., 23, 497–500. qin, j.t & zhou, l.p. (2012): effects of thermally transferred signals in the post-ir irsl sar protocol.– radiat. meas., 47, 710–715. rees-jones, j. (1995): optical dating of young sediments using finegrain quartz.– ancient tl, 13, 9–14. reimann, t., tsukamoto, s., naumann, m., & frechen, m. (2011): the potential of using feldspars for optical dating of young coastal sediments – a test case from darss-zingst peninsula (southern baltic sea coast).– quat. geochronol., 6, 207–222. robertson, a., karamata, s. & šarić, k. (2009): overview of ophiolites and related units in the late palaeozoic-early cenozoic magmatic and tectonic development of tethys in the northern part of the balkan region.– lithos, 108/1–4, 1–36. singhvi, a.k., bronger, a., sauer, w. & pant, r.k. (1989): thermo luminescence dating of loess-paleosol sequences in the carpathian basin (east-central europe): a suggestion for a revised chronology.– chem. geol. (isotope science section), 73, 307–317. sohbati, r., murray, a.s., buylaert, j.p., ortuño, m., cunha, p.p. & masana, e. (2011): luminescence dating of pleistocene alluvial sediments affected by the alhama de murcia fault wacha et al.: the chronology of the šarengrad ii loess-palaeosol section (eastern croatia) geologia croatica 203 (eastern betics, spain) – a comparison between osl, irsl and post-ir irsl ages.– boreas, 41, 250–262. spooner, n.a. (1994): the anomalous fading of infrared-stimulated luminescence from feldspars.– radiat. meas., 23/2–3, 625–632. thamó-bozsó, e. & kovács, l. (2007): evolution of quaternary to modern fluvial network in the mid-hungarian plain, indicated by heavy mineral distributions and statistical analysis of heavy mineral data.– in: mange, m. &wright, d. (eds.): heavy minerals in use, developments in sedimentology, vol. 58. elsevier, amsterdam, 491–514. thamó-bozsó, e., kovács, l.o., magyari, á. & marsi, i. (in press): tracing the origin of loess in hungary with the help of heavy mineral composition data.– quatern. int, doi: 10.1016/j. quaint.2013.04.030 thiel, c., buylaert, j.p., murray, a.s., terhorst, b., tsukamoto, s., frechen, m. & spafke, t. (2011a): investigating the chronostratigraphy of prominent palaeosols in lower austria using post-ir irsl dating.– q. sci. journ. (e&g), 60/1, 137–152. thiel, c., terhorst, b., jaburová, i., buylaert, j.-p., murray, a.s., fladerer, f.a., damm, b., frechen, m. & ottner, f. (2011b): sedimentation and erosion processes to late pleistocene sequences exposed in the brickyard of langenlois/lower austria.– geomorphology, 135, 295–307. thiel, c., buylaert, j.-p., murray, a., terhorst, b., hofer, i., tsukamoto, s. & frechen, m. (2011c): luminescence dating of the stratzing loess profile (austria) – testing the potential of an elevated temperature post-ir irsl protocol.– quatern. int., 234/1–2, 23–31. thiel, c., buylaert, j.-p., murray, a.s. & tsukamoto, s.(2011d): on the applicability of post-ir irsl dating to japanese loess.– geochronometria, 38/4, 369–378. thiel, c., horváth, e. & frechen, m. (in press): revisiting the loess/palaeosol sequence in paks, hungary: a post-ir irsl based chronology for the “young loess series”.– quatern. int., http:// dx.doi.org/10.1016/j.quaint.2013.05.045 thomsen, k.j., murray, a.s., jain, m. & bøtter-jensen, l. (2008): laboratory fading rates of various luminescence signals from feldspar-rich sediment extracts.– radiat. meas., 43, 1474–1486. tsukamoto, s., denby, p.m., murray, a.s. & bøtterjensen, l. (2006): time-resolved luminescence from feldspar: new insight into fading.– radiat. meas., 41, 790–795. tsukamoto, s., jain, m., murray, a., thiel, c., schmidt, e., wacha, l., dohrmann, r. & frechen, m. (2012): a comparative study of the luminescence characteristics of polymineral fine grains and coarse-grained kand na-rich feldspars.– radiat. meas., 47/9, 903–908. újvári, g., kovács, j., varga, g., raucsik, b. & marković, s.b. (2010): dust flux estimates for the last glacial period in east central europe based on terrestrial records of loess deposits: a review.– quaternary science reviews, 29, 3157–3166. wacha, l., mikulčić pavlaković, s., novothny, á., crnjaković, m. & frechen, m. (2011a): luminescence dating of upper pleistocene loess from the island of susak in croatia.– quatern. int., 234/1–2, 50–61. wacha, l., mikulčić pavlaković, s., frechen, m. & crnjaković, m. (2011b): the loess chronology of the island of susak, croatia.– quat. sci.journ. (e&g), 60/1, 153–169. wacha, l. & frechen, m. (2011): the geochronology of the “gorjanović loess section” in vukovar, croatia.– quatern. int., 240, 87–99. wallinga, j., murray, a. & duller, g.(2000): underestimation of equivalent dose in single-aliquot optical dating of feldspars caused by preheating.– radiat. meas., 31, 691–695. wintle, a.g. (1973): anomalous fading of thermoluminescence in mineral samples.– nature, 245, 143–144. wintle, a.g. & huntley, d.j.(1979): thermoluminescence dating of a deep-sea sediment core.– nature, 279, 710–712. wintle, a.g. & murray, a.s.(2006): a review of quartz optically stimulated luminescence characteristics and their relevance in singlealiquot regeneration dating protocols.– radiat. meas., 41, 369–391. manuscript received may 23, 2013 revised manuscript accepted september 09, 2013 available online october 16, 2013 2019 | 72/3 | 205–213 | 8 figs. | 4 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction dissolution of soluble rocks such as limestone, dolostone and gypsum, forms a special type of hydrogeological system, which is often reflected at the surface by the distinctive landscape known as karst. karst aquifers are characterized by extremely heterogeneous hydraulic properties manifested by rapid groundwater flows concentrated in conduits and disolutionally widened fractures, usually sparsely distributed, while the storage of groundwater is mainly related to surrounding fractured rock matrix and surficial epikarst (or subcutaneous) zone (goldscheider et al., 2007). because of its complexity, karst aquifer research necessitates an interdisciplinary approach (dreybrodt, 1988; covington et al., 2011). in addition to conventional methods, the use of environmental stable isotope tracers supplemented by statistical analysis, contributes to a better understanding of karst hydrogeology (criss et al., 2007; palmer, 2010; grimmeisen et al., 2017). stable isotopes of water (2h and 18o) are analysed for several reasons, e.g. to explore recharge processes and reservoir mixing (long & putnam, 2004; maloszewski et al., 2002), to explore vadose water mixing, residence times and storage in non-conduit parts of karst systems (palmer, 2010; moerman et al., 2014; dóša et al., 2011), to estimate mean recharge area elevations (barbieri et al., 2005; charideh & rahman, 2007), etc. detailed knowledge of the various processes within a karst hydrological system is crucial for the sustainable management of water resources, their allocation, and protection against pollution (mance et al., 2018 a, b). the black-box approach is often used northern velebit (croatia) karst hydrological system: results of a preliminary 2h and 18o stable isotope study dalibor paar1, diana mance2*, andrej stroj3 and mirja pavić3 1 university of zagreb, faculty of science, department of physics, 10 000 zagreb, croatia 2 university of rijeka, department of physics, 51 000 rijeka, croatia; (*diana.mance@uniri.hr) 3 croatian geological survey, zagreb, croatia doi: 10.4154/gc.2019.15 abstract researching the hydrogeological properties of karst systems is very challenging due to their extreme heterogeneity. a grey-box approach in karst research combines the results from classical hydrogeological methods with direct observations within the karstic underground, i.e. in the caves. isotope research has become a widely used method in the investigation of karst systems. the results presented are of a preliminary 2h and 18o stable isotope study of the northern velebit karst system (croatia) employing the grey-box approach. groundwater samples were collected during two summer expeditions in deep caves within the karst massif. monthly precipitation samples were also collected (at three locations between approx. 900 m and 1600 m altitude), as well as water samples at some of the most significant springs, i.e. discharge outlets of the system. for a single expedition, the stable isotope composition is almost constant, i.e. the stable isotope measurements are within the measurement error across the complete cave profile. simi­ lar characteristics across different caves during the same year were also noted. samples of water from the springs were taken during base­flow conditions and they have similar isotopic contents to the cave water. the results obtained indicate that homogenization of the water already occurs within the subsurface epikarst zone above the sampling locations in the caves, but a future extended sampling campaign during variable hydrologic conditions is needed to confirm this. the final research goal is to establish a conceptual grey­box model for the functioning of this complex hydrogeological system. in karst hydrogeological research. it is based on rainfall – spring discharge modelling and water quality relationships, which are usually insufficient to reveal all the complexity of the various processes that control groundwater flow through the karst underground. the grey-box approach to karst systems research, besides the input-output relations, employs additional data acquired directly from underground i.e. in caves. therefore, grey-box models are often more realistic and should be able to determine in more detail the system’s flow paths, linkages, stores, capacities, and throughput volumes than the black-box model (ford & williams, 2007). the research area of interest, the area of northern velebit (croatia), has been the subject of earlier hydrogeological investigations (pavičić, 1997; stroj, 2010), but a number of parameters required to model the system’s behaviour are still unknown (maloszewski, 2000). during the last few decades, many deep caves were discovered in the northern velebit karstic massif (bakšić et al., 2013), providing an opportunity to gather some new and direct insights into its hydrogeology (stroj & paar, 2019). the aim of the present preliminary study was to gather new insights into water infiltration and vadose flow properties within the karst massif by determining the δ2h and δ18o of water in various compartments of the system. precipitation samples were collected from three locations situated on mt. velebit hilltops, while groundwater samples were collected in the caves and at the main discharge outlets of the system. the results presented provide guidelines for establishing a new research project supplemented article history: manuscript received march 01, 2019 revised manuscript accepted june 10, 2019 available online october 31, 2019 keywords: caves, hydrogeology, karst, northern velebit, stable isotopes g eo lo gi a c ro at ic a geologia croatica 72/3206 by systematic and more frequent data collection. this could ultimately contribute to the development of a comprehensive conceptual hydrogeological model of the northern velebit system. 2. study area the study area is located in the croatian part of the dinaric karst, specifically in the northern part of a 145 km long velebit coastal mountain range (fig. 1), which is part of the external dinaric mountains separating the adriatic sea coast from the large karst poljes of the lika, and gacka rivers that sink in its hinterland. the northern velebit area, designated a national park, covers an area of approximately 109 km2. it has a form of high karst plateau geological observations in caves revealed complex geological structures expressed by widespread occurrences of compact carbonate breccias down to depths of approx. 1000 m below surface, e.g. in the lukina jama – trojama and velebita cave system (stroj & velić, 2015). the breccias in the caves often irregularly intersect a normal succession of jurassic limestones which points to their tectonic origin. this is commensurate with the assumption that the origin of the breccias observed at the surface is related to strong tectonic movements during the upper paleogene and lower neogene (bahun, 1974). pronounced resistance to the mechanical erosion of massive carbonate breccia together with its solubility dominates the surface relief forming processes. this enhances the development of distinctive karst corrosion landscapes where the entrances of the most important caves are located. such landscapes, together with occurrences of extremely deep caves, are instrumental in the national park designation. discovery and research of deep caves also revealed a very deep vadose zone of more than 1000 m inside the carbonate massif, as well as some characteristics of epiphreatic zone dynamics at the bottom of the vadose zone (bakšić et al., 2013; stroj & paar, 2019). sinkholes of the lika and gacka rivers are located on the eastern foothills of the northern velebit massif (fig. 2). in the past, the rivers sank completely into the karst massif and reappeared at numerous coastal springs and vruljas (submarine figure 1. location of mt. velebit and the research area (national park northern velebit) in the croatian part of dinaric karst. np – national park figure 2. a simplified sketch of the northern velebit karst system. (1) traced sinkholes in the massif`s hinterland, (2) main coastal discharge zones, (3) regional faults, (4) underground water flow connections determined by tracing tests, (5) sampled caves, (6) precipitation sampling locations, (7) meteorological station, (8) hydrogeological barrier formed by clastic rock formations, the rest of the area is built of various carbonate rocks (adapted with permission from stroj, 2010). intersected by numerous karst depressions separated by peaks and ridges (the highest peaks are 1600 – 1700 m a.s.l.). the largest part of northern velebit is composed of jurassic carbonate rocks, mainly limestones, and massive calcareous (limestone) breccias of upper paleogene to lower neogene age (mamužić et al., 1969; velić et al., 1974; velić & velić, 2009). clastic rock formations of triassic and palaeozoic ages form a hydrogeological barrier in the middle-southern parts of the velebit mountain range. the deeper position of these rocks in the northern part enables deep karstification and underground water flow from the hinterland towards the adriatic sea (fig. 2). the geological structure of the velebit mountain range is the consequence of two principal periods of tectonic activity (blašković, 1998; korbar, 2009). the first was the main phase of the dinarides orogenesis (eocene – miocene) with compressive movements oriented ne – sw. as a result of the regional tangential stress, deep nappe structures, folds and regional faults of dinaric strike (nw – se) have been formed. the second, socalled neotectonic phase, started probably during the late miocene or early pliocene, when the main stress changed to ns, resulting in further uplifts and transpressive deformations of older structures. the later phase played a crucial role for the present mountain morphology. g eologia c roatica paar et al.: northern velebit (croatia) karst hydrological system: results of a preliminary 2h and 18o stable isotope study 207 springs) along the coast on the western side of the massif (fig. 2) (pavičić, 1997; stroj, 2010). the distance from the sinkholes to the adriatic sea is approx. 20 km. today, the water from the two rivers is used for electricity production and is routed via a tunnel to the power plant on the coast. only occasional water surpluses sink into sinkholes occurring on average only a few days per year. taking into account the present conditions, the precipitation in the massif area is assumed to be the main water input for the system. 3. sampling and data precipitation samples were collected on a monthly basis from may 2012 to september 2013 on velebit at three locations oltari, sića, and crikvena (fig. 2). geographical coordinates and altitudes of the precipitation sampling sites are provided in table 1. precipitation sampling was performed usingsamples with antievaporation system (gröning et al., 2012). a total of 35 monthly precipitation samples were analysed for their stable isotope content (table 2). some of the samples are missing due to table 1. basic information about sampling locations. sampling location coordinates (latitude; longitude)* altitude (m a.s.l.) sample type hilltops sića 44.83970;14.96629 940 precipitation oltari 44.87348;14.98443 1300 precipitation crikvena 44.75878;14.98957 1641 precipitation caves velebita cave system** 44.75755;14.98633 1550 groundwater sirena pit** 44.76797;14.98763 1500 groundwater lukina jama** 44.76693;15.02638 1450 groundwater springs jurjevska žrnovnica (jz) 44.90161;14.91036 0 springwater starigrad senj (ss) 44.79790;14.88182 0 springwater bačvica (bc) 44.64268;14.94525 0 springwater štirovača (st) 44.69803;15.04988 1100 springwater *degree; wgs84 system **entrance table 2. basic information about precipitation samples. sampling location sampling period d2h (‰) d2h st.dev. (‰) d18o (‰) d18o st.dev. (‰) d-excess (‰) d-excess st.dev. (‰) amount (mm) sića may 2012 -66.62 1.00 -9.90 0.00 12.58 1.00 123.2 jun 2012 -27.21 0.27 -4.79 0.02 11.11 0.28 42.2 jul 2012 -30.14 1.00 -4.62 0.00 6.82 1.00 29.6 sep 2012 -69.85 0.03 -10.52 0.00 14.31 0.04 292 oct 2012 -62.74 0.18 -9.57 0.02 13.82 0.19 250.4 dec 2012 -57.12 0.35 -9.33 0.01 17.52 0.36 220.5 jan 2013 -69.50 0.10 -10.30 0.01 12.90 0.10 212.3 apr 2013 -62.12 0.64 -9.48 0.02 13.72 0.64 219.9 may 2013 -60.88 0.49 -9.80 0.02 17.52 0.49 219.1 jun 2013 -58.04 0.51 -8.87 0.02 12.92 0.51 21.1 jul 2013 -39.46 0.01 -6.16 0.02 9.82 0.06 36.5 aug 2013 -36.77 0.43 -6.49 0.04 15.15 0.44 59.2 sep 2013 -48.25 0.10 -8.00 0.01 15.75 0.10 197.2 oltari may 2012 -67.96 0.57 -9.84 0.01 10.76 0.57 132.6 jun 2012 -22.19 0.02 -3.92 0.01 9.17 0.02 32.4 jul 2012 -33.65 0.13 -5.17 0.00 7.71 0.13 32.8 sep 2012 -63.54 0.21 -9.53 0.00 12.70 0.21 241.1 oct 2012 -71.59 0.85 -10.73 0.01 14.25 0.85 220.5 dec 2012 -60.14 0.43 -9.56 0.00 16.34 0.43 220.5 jan 2013 -60.15 0.20 -9.39 0.00 14.97 0.20 208.5 apr 2013 -59.93 0.58 -9.04 0.02 12.39 0.58 219.2 may 2013 -61.03 0.41 -9.50 0.04 14.97 0.43 220.4 jun 2013 -51.64 0.18 -7.76 0.01 10.44 0.18 27.8 jul 2013 -37.56 0.44 -6.00 0.03 10.44 0.45 37.1 aug 2013 -36.89 0.21 -6.50 0.03 15.11 0.22 53.6 sept 2013 -48.39 0.00 -7.95 0.00 15.21 0.01 195.3 crikvena may 2012 -67.12 0.16 -10.02 0.02 13.04 0.17 132 jun 2012 -32.32 0.22 -5.60 0.00 12.48 0.22 51.7 jul 2012 -40.91 0.86 -6.29 0.01 9.41 0.86 29.6 sep 2012 -41.34 0.13 -6.88 0.02 13.70 0.14 74.7 oct 2012 -70.81 0.40 -10.75 0.00 15.19 0.40 204.1 may 2013 -61.16 0.08 -9.50 0.03 14.84 0.12 218.4 jun 2013 -8.42 0.10 3.2 jul 2013 -5.64 0.01 3.1 sep 2013 -58.41 0.08 -9.43 0.00 17.03 0.08 197.2 g eo lo gi a c ro at ic a geologia croatica 72/3208 sampling locations inaccessible during severe winter weather conditions. also, some samples had to be discarded due to an overflow of collectors (november 2012), while others were not suitable for the analysis due to insufficient volume (august 2012, summer 2013). water samples in the velebita cave system (vcs, entrance approx. 1550 m a.s.l., fig. 2) were collected during summer 2012 and summer 2013 spelaeological expeditions. a total of 20 groundwater samples were collected in the caves. samples were collected during dry summer days as summer storms increase the probability of sudden, increased water flows through cave passages, which is dangerous for cavers. the vcs sampling in 2012 started at a depth of approx. 100 metres, and continued to 1026 metres depth (table 3). in 2013, two samples were collected in the vcs at a depth of approx. 600 m, and one sample was collected in the lukina jama cave (entrance at approx. 1450 m a.s.l., fig. 2) at a depth of 1000 m. the 2013 expedition also included the sirena pit (entrance approx. 1500 m a.s.l., fig. 2) where one sample was collected at 45 m depth. basic information about groundwater sampling in the caves is provided in tables 1 & 3. the main coastal springs along the western foothills of the massif: bačvica (bc), jurjevska žrnovnica (jz) and starigrad senj (ss), were sampled in the summer of 2012 (fig. 2). additionally, two samples were collected from štirovača spring (st), located in the central part of the velebit massif at 1100 m a.s.l. (fig. 2). a total of 9 spring water samples were collected (table 4). all collected samples (precipitation, groundwater collected in caves and spring water) were stored in 50 ml, double capped, polyethylene bottles until analysis. the meteorological and hydrological service provided meteorological data for the zavižan meteorological station (1600 m a.s.l.), the only permanent meteorological station on northern velebit. 4. measurement and analysis stable isotope measurements were performed using the water equilibration technique (horita & kendall, 2004) on a delta plusxp (thermo finnigan) isotope ratio mass spectrometer. an hdo eq48/24 (isocal) equilibration unit and a dual inlet table 3. basic information about groundwater samples collected in caves. sampling location altitude (m a.s.l.) cave depth (m) sampling date d2h (‰) d2h st.dev. (‰) d18o (‰) d18o st.dev. (‰) d-excess (‰) d-excess st.dev. (‰) vcs 1462 -95 31-jul-12 -63.05 0.73 -9.3 0.01 11.35 0.73 vcs 977 -580 31-jul-12 -61.49 0.72 -9.66 0.00 15.79 0.72 vcs 977 -580 31-jul-12 -60.66 0.28 -9.6 0.00 16.14 0.28 vcs 772 -785 1-aug-12 -60.92 0.03 -9.47 0.01 14.84 0.04 vcs 707 -850 1-aug-12 -62.17 0.11 -9.57 0.01 14.39 0.11 vcs 687 -870 1-aug-12 -62.17 0.09 -9.59 0.01 14.55 0.09 vcs 582 -975 1-aug-12 -62.39 0.02 -9.72 0.01 15.37 0.04 vcs 531 -1026 2-aug-12 -62.98 0.49 -9.78 0.00 15.26 0.49 vcs 777 -780 2-aug-12 -60.69 0.85 -9.47 0.00 15.07 0.85 vcs 597 -960 2-aug-12 -61.47 0.96 -9.7 0.01 16.13 0.96 vcs 531 -1026 2-aug-12 -62.17 0.68 -9.72 0.00 15.59 0.68 vcs 531 -1026 2-aug-12 -62.24 0.65 -9.56 0.01 14.24 0.65 vcs 531 -1026 2-aug-12 -61.84 0.83 -9.69 0.00 15.68 0.83 vcs 1457 -100 3-aug-12 -62.13 0.42 -9.39 0.02 12.99 0.42 vcs 707 -850 4-aug-12 -62.02 0.8 -9.6 0.01 14.78 0.8 vcs 531 -1026 4-aug-12 -61.34 0.11 -9.68 0.00 16.1 0.11 vcs 977 -580 1-aug-13 -66.29 0.11 -10.23 0.01 15.55 0.12 vcs 977 -580 1-aug-13 -65.86 0.2 -10.19 0.02 15.66 0.2 lukina jama 475 -1000 2-aug13 -68.11 0.14 -10.44 0.03 15.41 0.16 sirena pit 1453 -45 5-aug-13 -70.19 0.15 -10.85 0.04 16.61 0.18 vcs – velebita cave system table 4. basic information about spring water samples. sampling location sampling date d2h (‰) d2h st.dev. (‰) d18o (‰) d18o st.dev. (‰) d-excess (‰) d-excess st.dev. (‰) jz s1 31-jul-12 -54.59 0.55 -8.08 0.02 10.05 0.55 jz s2 31-jul-12 -54.17 0.59 -8.12 0.01 10.79 0.59 ss 31-jul-12 -47.29 0.13 -7.17 0.01 10.07 0.13 bc s1 31-jul-12 -52.35 0.01 -8.11 0.01 12.53 0.02 bc s2 31-jul-12 -52.11 0.82 -8.10 0.01 12.69 0.82 bc sv 06-aug-12 -51.9 0.34 -8.18 0.01 13.54 0.34 ss 06-aug-12 -48.19 0.44 -7.34 0.01 10.53 0.44 st s1 07-aug-12 -58.18 0.17 -9.18 0.01 15.26 0.17 st s2 07-aug-12 -57.64 0.58 -9.16 0.01 15.64 0.58 jz s1 – jurjevska žrnovnica sample 1; jz s2 – jurjevska žrnovnica sample 2; ss – starigrad senj; bc s1 – bačvica sample 1; bc s2 – bačvica sample 2; bc sv – bačvica spring vrulja; st s1 – štirovača sample 1; st s1 – štirovača sample 2 g eologia c roatica paar et al.: northern velebit (croatia) karst hydrological system: results of a preliminary 2h and 18o stable isotope study 209 system (thermo finnigan) were peripheral units. δ2h and δ18o values are expressed relative to the vienna standard mean ocean water (vsmow) standard. the measurement precision was better than 0.1 ‰ in case of δ18o, and better than 1 ‰ for δ2h. accordingly, the measurement error for d-excess is calculated to be 1.04 ‰ (criss et al., 2007). normalization and analyses of measurements were performed by the us geological survey laboratory information management system. statistical calculations were conducted in statistica 13.0 (statsoft inc., tulsa, ok, usa). the descriptive statistics for data that are normally distributed are presented with arithmetic mean and standard deviation, while data that do not follow a normal distribution are presented with the median and minimum and maximum values. to test whether a sample distribution matches the characteristics of a normal distribution we used the kolmogorov-smirnov test. a measure of the linear correlation between two variables is expressed with the pearson correlation coefficient (r). the relationship between two variables was determined by linear regression analysis. testing the differences between the continuous variables was accomplished by t-test (for normally distributed data) or mann-whitney test (for data that do not follow a normal distribution), and regarding the categorical variables by c2-test. the level of statistical significance was chosen at p < 0.05. 5. results and discussion 5.1. meteorological conditions in the hydrological years 2012 and 2013 daily air temperatures of the hydrological year 2012 (oct 2011 – sep 2012) and the hydrological year 2013 (oct 2012 – sep 2013) do not differ significantly (mann-whitney test, p = 0.43). the average monthly air temperatures for the period showed typical seasonal behaviour with the highest temperatures in summer and the lowest temperatures in the winter months (fig. 3a). monthly precipitation during the hydrological year 2013 (median 218.6 mm; minimum 45.1 mm; maximum 462.9 mm) was significantly higher compared to the hydrological year 2012 (median 86.2; minimum 0.8 mm; maximum 278.3 mm) (mann-whitney test, p = 0.04). as shown in fig. 3a, this is particularly evident during the period jan – mar 2012 (very low precipitation) and jan – mar 2013 (rainy period). during the hydrological year 2013 snow was present for longer in comparison to the previous hydrological year (c2-test, p = 0.003, fig. 3b). in the hydrological year 2013 the snow cover was continuously present for 164 days (melting in may 2013), while during the hydrological year 2012 the snow cover was present for 100 consecutive days (melting in march 2012; with fresh snow in april and may 2012). also, the snow layers were thicker in the winter season 2012–2013 in comparison to the same season in 2011–2012 (mann-whitney test, p = 0.001). the thickest snow layer of 2011–2012 was 120 cm (feb 2012), while in the winter season 2012-2013 the maximum snow thickness was 322 cm (march 2013, fig. 3b). 5.2. precipitation due to the small number of precipitation samples, we weren’t able to set up a local meteoric water line (lmwl) that would be relevant for a longer period. nevertheless, there is a statistically significant correlation between δ2h and δ18o precipitation values (r = 0.99; p < 0.001). a corresponding precipitation regression line: d2h = 7.15 ∙ d18o + 6.14 ‰ (r2= 0.98) plots close to the global meteoric water line (gmwl) that expresses the worldwide average (craig, 1961) (fig. 4). given the strong correlation between δ2h and δ18o precipitation values, only δ18o values are mentioned below. the time series of precipitation δ18o shows higher values in the summer months than during the rest of the year (fig. 5a). this is typical for low latitudes where ‘the amount effect’ accounts for δ variations: low isotopic signals in months with significant precipitation, and more positive isotopic signals in months with scarce rainfall (dansgaard, 1964). the average d-excess value of precipitation samples is (13.16 + 2.72) ‰. fig. 5b shows that precipitation d-excess values are lower during summer than during the rest of the year. this is comparable to previously reported results from the bordering region with similar climatic conditions (mance et al., 2014). therefore, we can conclude that the sources of the precipitation are comparable, i.e. that the dominant summer precipitation in the area of northern velebit originates in the atlantic ocean, while in winter there is the predominance of mediterranean-originated precipitation. figure 3. meteorological conditions at the zavižan station over the study period. time series of a) average monthly air temperatures and monthly precipitation amounts; b) number of days with the presence of a snow layer and maximum snow layer thicknesses. figure 4. δ2h – δ18o diagram of monthly precipitation samples (ot – oltari, sc – sića, cr – crikvena), groundwater samples collected in caves during expeditions 2012 & 2013 (sirena pit, lukina jama, vcs – velebita cave system), and groundwater samples collected at springs (jz – jurjevska žrnovnica, ss – starigrad senj, bc – bačvica, st – štirovača). gmwl – global meteoric water line. g eo lo gi a c ro at ic a geologia croatica 72/3210 5.3. groundwater the isotope measurements for samples collected in 2012 across the vcs profile (depths >1000 m) show a very small variation of δ18o values (figure 6, table 3). the average δ18o value of these samples is (-9.59 + 0.13) ‰. the values are within a narrow range (< 0.5 ‰) and without the presence of a uniform vertical gradient. stable isotope composition of the samples collected in caves corresponds to the lower part of the precipitation cluster (fig. 4), indicating that the groundwater flowing through the cave during low water conditions is dominantly fed by the september – may precipitation (fig. 5). the relatively constant isotopic composition of the samples suggests that groundwater homogenization already occurs within the epikarst zone. the epikarst zone comprises a relatively shallow, but most intensely fractured and karstified subsurface zone where precipitation quickly infiltrates and could be temporarily stored (mangin, 1974; williams, 1983). water stored in such epikarst storages during the wet season slowly drains into the underlying vadose zone during the dry summer season. therefore, we can conclude that consistent water characteristics across the vcs profile suggest that the cave streams are dominantly fed from the epikarst storages. the substantial inflow of water with different characteristics from deeper storages, i.e. from fractures in rock walls along the cave profile, would probably be reflected by more pronounced variations in the stable isotope composition with cave depth. it should be mentioned once again that all samples were taken during low water conditions. if samples were collected during summer storms, when fast infiltration can bypass epikarst storages through fractures widened by dissolution, δ18o would probably show different values, i.e. the isotopic composition would be more influenced by recent (summer) precipitation. cave samples collected during the 2013 expedition have lower δ18o values than those from the 2012 expedition (fig. 6, table 3). these observed differences are tentatively explained by the characteristics of the rainfall period that preceded the second expedition. namely, lower isotopic values could be associated with higher levels of snow and rainfall during the hydrological year 2013 in comparison with hydrological year 2012 (fig. 3). unfortunately, sampling along the complete vcs profile was not performed in 2013, and only samples at approx. 600 m depth were available. it is interesting that the sample taken in the lukina jama in the same year has a very similar isotopic value. this suggests similar recharge mechanisms for different caves in the area. it is generally considered that the preserved seasonal amplitude of the spring water isotopic signal indicates a mean residence time of < 1 year (trček & zojer, 2009, lauber & goldscheider, 2014). if lower isotopic values of the sampled groundwater in 2013 (fig. 6) are a consequence of the characteristics of the preceding wet season, this points to a relatively short mean residence time of groundwater in storages before draining to the cave conduits. nevertheless, this should be confirmed by longer and more extensive sampling of the precipitation, and groundwater in the caves. the sample collected at a depth of 45 m from the sirena pit in 2013 was depleted in comparison to other samples collected figure 5. a) δ18o series and the amount of monthly precipitation samples; b) d-excess series for the monthly precipitation samples. error bars represent a measurement error of 1.04 ‰. ot – oltari, sc – sića, cr – crikvena. figure 6. groundwater δ18o values at corresponding sampling altitudes. error bars represent a measurement error of 0.1 ‰. lower altitudes indicate greater cave depths. isotopic signals connected with a dashed line originate from samples collected in the velebita cave system in 2012. figure 7. groundwater d-excess values at corresponding sampling altitudes. error bars represent measurement errors of 1.04 ‰. lower altitudes indicate greater cave depths. isotopic signals connected with dashed line originate from samples collected in the velebita cave system in 2012. g eologia c roatica paar et al.: northern velebit (croatia) karst hydrological system: results of a preliminary 2h and 18o stable isotope study 211 that year (fig. 6). we may attribute the depletion of the sample to the probable origin of the water sampled from the snowmelt, as for snow lower isotopic values are expected (mance, 2014). also, perennial snow accumulation was reported by the cavers in a deep dolina where the cave entrance is located. for d-excess values of the samples collected in caves, we may also see that most of the data plots within the range of the measurement error (fig. 7). the average d-excess value of cave collected samples is (14.89 + 1.26) ‰. approximately constant d-excess values of cave water samples indicate the absence of significant evaporation before infiltration, i.e. fast infiltration of precipitation to the epikarst storage. similar d-excess values of cave samples collected in 2013 and 2012 indicate similar geographic origins of the precipitation recharging the system. the average d-excess value of samples collected in caves corresponds to the d-excess of precipitation collected in the period sep 2012 – may 2013 (14.61 + 1.57) ‰ (t-test, p = 0.28). this is an additional indicator of predominant groundwater recharge by the winter precipitation. the extreme d-excess values have samples collected at the highest altitudes i.e. the lowest cave depths. this may be explained by some contribution of newly infiltrated precipitation in the sampled water. fig. 4 shows that the samples from springs plot above the samples collected in caves. water from coastal springs was slightly brackish due to seawater intrusion into the karst aquifer, which was manifested by the elevated conductivity of the spring water. specific conductivity measured during sampling at the bc, jz and ss springs was 6.7-7.0 ms/cm, 7.9 ms/cm and 13.8-14.7 ms/cm, respectively. specific conductivity of the spring water during high flow conditions (when seawater intrusion doesn’t affect it) was approx. 0.3-0.4 ms/cm (stroj, 2010). we estimated the seawater proportion in the spring water samples by applying two-component mixing analysis (peterlla & celico, 2013) based on the sample conductivities, unaffected groundwater conductivity and seawater conductivity (55 ms/cm, measured during sampling). the calculated proportion of seawater in the spring water was approx. 12 % at bc, 14 % at jz and 25 % at ss springs. we further applied two-component mixing analysis for corrections of coastal springs’ isotopic compositions. corrections were based on the estimated proportion of seawater and presumed seawater isotopic composition of δ18o ≈ +1‰ (gat et al., 2003). after the correction, groundwater samples from the springs have similar values to water from the caves in the same year (tables 3 & 4), confirming the coastal springs are predominantly fed by the recharge from the massif. stable isotope compositions of groundwater collected in both, caves and springs, coincide with the precipitation regression line (fig. 4). this indicates the meteoric origin of the groundwater without significant influence of additional post-precipitation fractionation. the only sampled inland spring, located in the central, but somewhat lower part of the massif (1100-1300 m a.s.l.) is the štirovača (st) spring (fig. 2). both st samples have δ18o values which are comparable to, but slightly less depleted than those collected in caves (tables 3 & 4) suggesting it is fed from its immediate surroundings. this is consistent with the geological situation: the spring is located close to the geological boundary with the impermeable clastic rocks situated on the southern margin of the northern velebit. the δ18o values of samples collected in the caves and the st spring are comparable to values for some of the gacka river springs sampled during summer months of 2005 – 2011 (mandić et al., 2008; ozyurt et al., 2014). this indicates similar mechanisms of winter (wet) season recharge of water storages, which are slowly drained during the dry season. the st d-excess values are comparable to d-excess values of samples from the caves (tables 3 & 4). this is another indication of similar water feeding into the caves and the st spring. lower d-excess values of coastal springs are probably a consequence of mixing with seawater or/and a small contribution from recent summer precipitation. 5.4. preliminary conceptual model of the northern velebit hydrogeological system taking groundwater samples directly from the deep caves within the massif permitted the use of the grey-box model instead of the black-box model that takes into account only system’s input and output data. fig. 8 shows a conceptual model of the northern figure 8. conceptual model of northern velebit karst hydrological system. sampled caves are shown in black, other known caves are in grey, and the remaining conduits are schematic. g eo lo gi a c ro at ic a geologia croatica 72/3212 velebit hydrological system developed on the basis of the results presented here, including the results of previous spelaeological and hydrogeological research (paar et al., 2008; stroj, 2010; bakšić et al., 2013; stroj & paar, 2019). the proposed conceptual model includes provision of significant storage capacities within the epikarst zone, situated immediately below the surface, down to the depth of a few metres (or few tens of metres in case of massive and well lithified carbonate breccias). during the dry season, the flow in cave conduits is mostly fed by the water stored in the epikarst during the previous winter / wet season. across the vadose zone, the flow is fast and predominantly concentrated in conduits, which is expressed by constant isotope characteristics. the preliminary findings presented earlier suggest that the mean residence time of water stored in the system is relatively short, possibly less than a year. this is indicated by the cave water stable isotope composition influenced by characteristics of the preceding winter / wet season. coastal karst springs, that are the main discharge points of the system, are predominantly fed by the water of similar characteristics as that observed in the caves. the infrequent nature and short duration of concentrated inflows from sinkholes on the lika and gacka rivers under present conditions limits their significance. therefore, it may be concluded that epikarst storages on the massif are probably the main source of spring water during the base flow conditions. 6. conclusions the paper presents the results of a preliminary stable isotope study of the waters of the northern velebit karst hydrological system. the aim of the study was the application of a grey-box modelling approach to karst hydrogeological research. the approach combined the results from classical hydrogeological methods with the findings from the sampling of the water in the caves. the study used stable isotope analysis of water samples as a tool to investigate the functioning of the karst hydrogeological system. the results of this study, together with the results from previous research enabled us to develop a preliminary conceptual recharge and storage model of the northern velebit karst system. the main features incorporated in the model are: • groundwater storage is mainly related to the function of the epikarst zone; • recharge of the epikarst occurs mainly during the wet / winter season; • the mean residence time of epikarst storage is relatively short, probably within one year; • the deeper vadose zone has a low storage capacity and water flows within are concentrated in conduits; • system outflow via coastal springs and vruljas (submarine springs) in the base flow conditions is dominantly fed by epikarst storage of the massif. based on the obtained results, we conclude that the grey-box modelling approach is an improvement in the investigation of complex karst systems. in addition to classical hydrological methods, spelaeological investigations play an important role in this type of approach and give researchers the opportunity to study different hydrological processes in situ. although the number of analysed water samples is relatively low, limiting their interpretation, this study provides preliminary results, enabling the establishment of a recharge and storage model for the system that will serve as a basis for future research. establishing a future longer term monitoring programme for the northern velebit hydrogeological system would provide data required to further test and upgrade the presented model. this would provide a better and more detailed understanding of the functioning of the northern velebit karst system and enable efficient water management and nature conservation to be undertaken. references bahun, s. (1974): tectogenesis of the velebit and the formation of the jelar deposits.– geološki vjesnik, 27, 35–51. bakšić, d., paar, d., stroj, a. & lacković, d. (2013): northern velebit deep caves.– in: filippi, m. & bosak, p. (eds.): proceedings of the 16th international congress of speleology, brno, jul. 21–28, 2013. czech speleological society and uis, brno, 2013, 24–29. barbieri, m., boschetti, t., pettita, m. & tallini, m. (2005): stable isotope (2h, 18o and 87sr/86sr) and hydrochemistry monitoring for groundwater hydrodynamics analysis in a karst aquifer (gran sasso, central italy).– appl. geochem., 20, 2063–2081. doi: 10.1016/j.apgeochem.2005.07.008 blašković, i. (1998): the two stages of structural formation of the coastal belt of the external dinarides.– geol. croat., 51/1, 75–89. doi: 10.4154/gc.1998.09 charideh, a & rahman, a. (2007): environmental isotopic and hydrochemical study of water in the karst aquifer and submarine springs of the syrian coast.– hydrogeol. j., 15/2, 351–364. doi: 10.1007/s10040-006-0072-x covington, m.d., doctor, d.h., king, j.n. & wicks, c.m. (2011): research in karst: a model for future directions in hydrologic science? – agu hydrology section newsletter [internet, cited 2019 feb 14], 5 p. available from: https://hydrology.agu.org/wp-content/uploads/sites/19/2014/10/aguhydro-201107.pdf craig, h. (1961): isotopic variations in meteoric waters.– science, 133/3465, 1702–1703. doi: 10.1126/science.133.3465.1702 criss, r., davisson, l., surbeck, h. & winston, w. (2007): isotopic methods.– in: goldscheider, n. & drew, d. (eds.): methods in karst hydrogeology. taylor & francis, london, 123–146. dansgaard, w. (1964): stable isotopes in precipitation.– tellus, 16/4, 436–468. doi: 10.1111/j.2153-3490.1964.tb00181.x dóša, m., holko, l. & kostka, z. (2011): estimation of the mean transit times using isotopes and hydrograph recessions.– bodenkultur., 62/1–4, 47–52. dreybrodt, w. (1988): processes in karst systems.– springer-verlag, berlin. doi: 10.1007/978-3-642-83352-6 ford, d. & williams, p. (2007): karst hydrogeology and geomorphology.– wiley chichester. doi: 10.1002/9781118684986 gat, j.r., klein, b., kushnir, y., roether, w., wernli h., yam, r. & shemesh, a. (2003): isotope composition of air moisture over the mediterranean sea: an index of the air–sea interaction pattern.– tellus b, 55, 953–965. doi: 10.1034/j.1600-0889.2003.00081.x goldscheider, n., drew, d. & worthington, s. (2007): introduction.– in: goldscheider, n. & drew, d. (eds.): methods in karst hydrogeology. taylor & francis, london, 2–7 p. doi: 10.1201/9781482266023 grimmeisen, f., lehmann, m.f., liesch, t., goeppert, n., klinger, j., zopfi, j. & goldscheider, n. (2017): isotopic constraints on water source mixing, network leakage and contamination in an urban groundwater system.– sci. total environ., 583, 202–213. doi: 10.1016/j.scitotenv.2017.01.054 gröning, m., lutz, h.o., roller-lutz, z., kralik, m., gourcy, l. & pöltenstein, l. (2012): a simple rain collector preventing water re-evaporation dedicated for δ18o and δ2h analysis of cumulative precipitation samples.– j. hydrol., 448–449, 195–200. doi: 10.1016/j.jhydrol.2012.04.04 horita, j. & kendall, c. (2004): stable isotope analysis of water and aqueous solutions by conventional dual-inlet mass spectrometry.– in: de groot, p.a. (ed.): handbook of stable isotope analytical techniques. elsevier, 1–37. doi: 10.1016/b978-044451114-0/50003-x korbar, t. (2009): orogenic evolution of the external dinarides in the ne adriatic region: a model constrained by tectonostratigraphy of upper cretaceous to paleogene carbonates.– earth sci reviews., 96/4, 296–312. doi: 10.1016/j.earscirev.2009.07.004 lauber, u. & goldscheider, n. (2014): use of artificial and natural tracers to assess groundwater transit-time distribution and flow systems in a high-alpine karst system (wetterstein mountains, germany).– hydrogeol. j., 22, 1807–1824. doi: 10.1007/s10040-014-1173-6 long, a.j. & putnam, l.d. (2004): linear model describing three components of flow in karst aquifers using 18o data.– j. hydrol., 296, 254–270. doi: 10.1016/j. jhydrol.2004.03.023 maloszewski, p., stichler, w., zuber, a. & rank, d. (2002): identifying the flow systems in a karstic-fissured-porous aquifer, the schneealpe, austria, by g eologia c roatica paar et al.: northern velebit (croatia) karst hydrological system: results of a preliminary 2h and 18o stable isotope study 213 modeling of environmental 18o and 3h isotopes.– j. hydrol., 256, 48–59. doi: 10.1016/s0022-1694(01)00526-1 maloszewski, p. (2000): lumped-parameter models as a tool for determining the hydrological parameters of some groundwater systems based on isotope data.– in: dassargues, a. (ed.): tracers and modelling in hydrogeology, international conference, liège, 2000, iahs press, london, 271–276. mamužić, p., milan, a., korolija, b., borović, i. & majcen, ž. (1969): osnovna geološka karta sfrj 1:100000, list rab [basic geological map of sfry 1:100000, rab sheet − in croatian].– institute of geology, zagreb, federal geol. inst., belgrade. mance, d., hunjak, t., lenac, d., rubinić, j. & roller-lutz, z. (2014): stable isotope analysis of the karst hydrological systems in the bay of kvarner (croatia).– app. radiat. isotopes, 90, 23–34. doi:10.1016/j.apradiso.2014.03.001 mance, d. (2014): karakterizacija krškog vodonosnika temeljena na prostornim i vremenskim promjenama stabilnih izotopa vodika i kisika [characterization of a karst aquifer based on the spatial and temporal variations of hydrogen and oxygen stable isotopes – in croatian, with an english abstract].– unpubl. phd thesis, faculty of science, university of zagreb, 124 p. https://repozitorij.pmf.unizg.hr/islandora/object/pmf%3a1770 mance, d., mance, d. & vukić lušić, d. (2018a): environmental isotope 18o in coastal karst spring waters as a possible predictor of marine microbial pollution.– acta adriat., 59/1, 3–15. doi: 10.32582/aa.59.1.1 mance, d., mance, d. & vukić lušić, d. (2018b): marine pollution differentiation with stable isotopes of groundwater.– pomorstvo, 32/1, 80–87. doi: 10.31217/p.32.1.10 mandić, m., bojić, d., roller-lutz, z., lutz, h.o. & krajcar bronić, i. (2008): note on the spring region of gacka river (croatia).– isot. environ. healt. s. 44/2, 201–208. doi: 10.1080/10256010802066364 mangin, a. (1974): contribution à l’étude hydrodynamique des aquifères karstiques.– ann. spéléol. 29(3), 283-332; (4), 495-601. moerman, j.w., cobb, k.m., partin, j.w., meckler, a.n., carolin, s.a., adkins, j.f., lejau, s., malang, j., clark, b. & tuen, a.a. (2014): transformation of enso-related rainwater to drip water δ18o variability by vadose water mixing. geophys.– res. lett., 41, 1–9. doi: 10.1002/2014gl061696 ozyurt, n.n., lutz, h.o., hunjak, t., mance, d. & roller-lutz, z. (2014): characterization of the gacka river basin karst aquifer (croatia): hydrochemistry, stable isotopes and tritium-based mean residence times.– sci. total environ., 487, 245–254. doi: 10.1016/j.scitotenv.2014.04.018 paar, d., ujević, m., bakšić, d., lacković, d., čop, a. & radolić, v. (2008): physical and chemical research in velebita pit (croatia).– acta carsol., 37/2–3, 273–278. doi: 10.3986/ac.v37i2-3.151 palmer, a.n. (2010): understanding the hydrology of karst.– geol. croat., 63/2, 143–148. doi: 10.4154/gc.2010.11 pavičić, a. (1997): hydrogeological evaluation of water retaining properties of the kosinj reservoir (lika, croatia).– geol. croat., 50/2, 289–298. peterlla, e. & celico, f. (2013): mixing of water in a carbonate aquifer, southern italy, analysed through stable isotope investigations.– int. j. speleol., 42/1, 25–33. doi: 10.5038/1827-806x.42.1.4 stroj, a. (2010): podzemni tokovi u zaleđu krških priobalnih izvora na području velebitskog kanala [underground water flows in the hinterland of the velebit channel coastal karst springs – in croatian, with an english abstract].– phd thesis, faculty of mining, geology and petroleum engineering, university of zagreb, 259 p. stroj, a. & velić, i. (2015). geološki profil jamskog sustava lukina jama–trojama na sjevernom velebitu [geologic cross-section along the lukina jama –trojama cave system – in croatian].– presentation at: 5th croatian geological congress with international participation, sep 23–25, 2015; osijek, croatia. stroj, a. & paar, d. (2019): water and air dynamics within a deep vadose zone of a karst massif: observations from the lukina jama–trojama cave system (−1,431 m) in dinaric karst (croatia).– hydrol. process., 33/4, 551–561. doi: 10.1002/ hyp.13342 trček, b. & zojer, h. (2009): recharge of springs. in: kresić, n., stevanović, z. (eds.): groundwater hydrology of springs.– elsevier, amsterdam, 87–127. velić, i., bahun, s., sokač, b. & galović, i. (1974): osnovna geološka karta sfrj 1: 100 000, list otočac l 33-115. [basic geologic map of sfry 1:100000, geology of otočac sheet – in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd, 44 p. velić, i. & velić, j. (2009): od morskih plićaka do planine. geološki vodič kroz nacionalni park sjeverni velebit [from marine shallows to the mountain: geological guidebook through the northern velebit national park – in croatian].– np sjeverni velebit, krasno (croatia). williams, p.w. (1983): the role of the subcutaneous zone in karst hydrology.– j. hydrol., 61/1–3, 45–67. doi: 10.1016/0022-1694(83)90234-2 2016 | 69/2 | 187–194 | 4 figs. | 1 tab. | 1 pl. | www.geologia-croatica journal of the croatian geological survey and the croatian geological society 1. introduction the upper cretaceous shallow-water limestones of the periadriatic region (adriatic, apenninic, and apulian carbonate platforms) contain a rich fauna of large-sized benthic foraminifera, many of them with special biostratigraphic importance (e.g., torre, 1966; luperto sinni, 1976; de castro, 1974; cvetko tešović et al., 2001; korbar & husinec, 2003; velić, 2007; checconi et al., 2008; frijia et al., 2015). in the croatian part of the adriatic-dinaridic carbonate platform, a shallow-water facies rich in benthic foraminifera known as the pučišća formation was originally described from the island of brač (gušić & jelaska, 1990). the island of brač is situated along the central part of the adriatic-dinaridic carbonate platform (adcp; cf. jenkyns, 1991; gušić & jelaska, 1990; pamić et al., 1998; jelaska, 2002) or adriatic carbonate platform (adcp; cf. vlahović et al., 2005). during the mesozoic, several long-lived isolated carbonate platforms existed in the me cretaciclavulina gusici n. gen., n. sp. (?family valvulinidae berthelin, 1880), a new larger benthic foraminifer from the lower campanian of brač island, croatia felix schlagintweit1 and blanka cvetko tešović2 1lerchenauerstr. 167, d-80935 münchen, germany; (corresponding author: felix.schlagintweit@gmx.de) 2university of zagreb, faculty of science, department of geology, horvatovac 102a, zagreb, croatia; (bcvetko@geol.pmf.hr) doi: 10.4154/gc.2016.17 abstract the larger benthic foraminifera cretaciclavulina gusici n. gen., n. sp. is described from the lower campanian pučišća formation of the island of brač, croatia. with its elongate test, trochospiral to uniserial coiling, simple chambers, paraporous wall structure, and areal aperture provided with a cribrate apertural plate, cretaciclavulina is tentatively placed into the family valvulinidae berthelin, 1880. besides neobalkhania bignoti cherchi, radoičić & schroeder, 1991, fleuryana adriatica de castro, drobne & gušić, 1994, and reticulinella fleuryi cvetko, gušić & schroeder, 1997, cretaciclavulina gusici represents the fourth benthic foraminifera newly described from the upper cretaceous shallow-water carbonates of brač island. article history: manuscript received august 19, 2015 revised manuscript accepted march 30, 2016 available online june 1, 2016 keywords: benthic foraminifera, wall structure, valvulinidae, palaeotextulariidae, upper cretaceous, croatia diterranean region (the former central tethys; present-day periadriatic area). the adcp was the largest of these platforms with relatively well preserved, mainly shallow-marine successions occasionally interrupted by episodes of emersion or drowning. from the pučišća formation of brač island, three benthic for aminifera have already been introduced from thin-section mate rial: neobalkhania bignoti cherchi, radoičić & schroeder, 1991, fleuryana adriatica de castro, drobne & gušić, 1994, and reticulinella fleuryi cvetko, gušić & schroeder, 1997. another new taxon is reported here is cretaciclavulina gusici n. gen., n. sp. 2. geological setting 2.1. lithostratigraphy on the island of brač, situated along the central part of the croatian adriatic coast (fig. 1), an almost complete, relatively undisfigure 1. map showing the location and geology of brač island, and type locality of cretaciclavulina gusici n. gen., n. sp. (modified after gušić & jelaska, 1990, cvetko tešović et al., 2001 and steuber et al., 2005). g eo lo gi a c ro at ic a geologia croatica 69/2188 šić & jelaska, 1990), ranging in age from cenomanian to maastrichtian (fig. 2): – the milna formation (cenomanian) comprises bioclastic (including foraminifera, rudists and other mollusca) wackestones to grainstones alternate with microbial laminites, occasional slump features, and rare intraformational breccias (gušić & jelaska, 1990; korbar et al., 2012). – the sveti duh formation (uppermost cenomanian–lower turonian) comprises pelagic skeletal wackestones with planktonic foraminifera and calcispheres indicate drownturbed, and well-exposed upper cretaceous succession of the adcp is exposed. this succession has served as a representative example for the upper cretaceous shallow-water carbonate development of the adcp (figs. 1, 2). palaeogene deposits are also present along the northwestern and, as scattered outcrops, along the southeastern coast of the island (fig. 1). the upper cretaceous platform limestones represent a thick „layer-cake” sedimentary succession (up to 1500 m), consisting predominantly of small-scale shallowing-upward cycles (gušić & jelaska, 1990). the succession has been subdivided into six lithostratigraphic units (pejović & radoičić, 1987; gufigure 2. stratigraphic synthesis of the upper cretaceous deposits of brač island with detailed lithology and selected foraminiferal assemblage of pučišća formation (adapted from gušić & jelaska, 1990, cvetko tešović et al., 2001 and steuber et al., 2005). g eologia c roatica felix schlagintweit and blanka cvetko tešović: cretaciclavulina gusici n. gen., n. sp. (?family valvulinidae berthelin, 1880) ... 189 ing of the adcp (jenkyns, 1991; gušić & jelaska, 1990; davey & jenkyns, 1999; korbar et al., 2012). – the gornji humac formation (upper turonian–lower campanian) comprises oncoid-bearing beds in the lower part (e.g. the „gračišće oncolite” member) during the late turonian–early coniacian, which cap the underlying pelagic deposits and evidence a shallowing and reinstallation of carbonate platform environments, which were gradually less restrictive and more favourable for populations of shallow-water benthic organisms. – the dol formation (coniacian–lower campanian) comprises micrites with abundant calcispheres and planktonic foraminifera indicating a second late cretaceous pelagic episode. – the pučišća formation (santonian–middle campanian): platform sediments with rudists in parautochthonous position and shallow-water bioclastic limestones indicate the gradual infilling of the intraplatform trough, known as the brač „marble” member. with the progradation of the platform, the protected back-margin environments gradually occupied larger areas until they completely overlaid the brač „marble” member. these environments are represented by the two superpositional-lateral subunits of the rasotica member (rudist biostromes, bioclastic floatstones to rudstones and foraminiferal wackestones/packstones with rich and diverse assemblages of larger benthic imperforate foraminifera) and the lovrečina member (uppermost member characterized by regularly developed shallowingupward sequences with features indicating emergence conditions with subaerial erosion at the top, probably reflecting a global drop of sea level in the middle to late campanian). – the sumartin formation (upper campanian–maastrichtian) represents the regressive cycles of the maastrichtian, above the late campanian emersion, which were deposited in peritidal environments. the new benthic foraminifer described in the present paper was observed in the campanian deposits of the uppermost part of the gornji humac and are more frequent in the pučišća formation (rasotica and lovrečina members). 2.2. biostratigraphy pejović & radoičić (1987) subdivided the upper cretaceous deposits into six formations mainly based on benthic foraminifera and rudists. six formations were also recognized by gu šić & jelaska (1990), but their lithoand chronostratigraphic interpretation differs from that of pejović & radoičić (1987). they emphasized the diachronous character of some formation boundaries (fig. 2) and subdivided some of them into smaller units. rudist bivalves and benthic microfossils have been studied comprehensively as biostratigraphic markers for the upper cretaceous succession of brač (polšak et al., 1982; gušić & jelaska, 1990; cvetko tešović et al., 2001, korbar, 2003; steuber et al., 2005 and references therein) and the type localities of several taxa are located on the island. the pučišća formation contains especially rich assemblages of larger benthic foraminifera dominated by various imperforate taxa in the rasotica and lovrečina members and hyaline foraminifera in the brač „marble” member. these assemblages were used for the interpretation of stratigraphic and palaeoenvironmental features (gušić & jelaska, 1990; cvetko te šović et al., 2001). cvetko tešović et al. (2001) described these assemblages in detail including taxonomic, phylogenetic, stratigraphic and palaeoecologic aspects. the late (but not latest) campanian age of the pučišća formation is largely based on the age determination of the brač „marble” member. gušić & jelaska (1990) gave stratigraphic priority to the relevant and well-studied larger benthic foraminifera (orbitoidids and siderolitids). based on numeric ages derived from strontium-isotope stratigraphy (sis) of low-mg calcite of rudist shells, steuber et al. (2005) revised the chronostratigraphy of the coniacian– maastrichtian platform carbonates of the island of brač. according to the strontium-isotope stratigraphy, the pučišća formation is mid-santonian to late middle campanian in age. based on benthic foraminifera, especially calveziconus lecalvezae caus & cornella, the samples containing cretaciclavulina gusici n. gen. n. sp. can be assigned to the lower campanian (see revised ranges of frijia et al., 2015). 3. material and repository the micropalaeontological analysis of samples from the pučišća formation was performed on about 200 thin sections. sections of cretaciclavulina gusici n. gen, n. sp. were only observed in 15 of them. the investigated samples are the property of the croatian geological survey and their repository (inventory numbers: 10807−10815) is currently in the geological-palaeontological department of the croatian natural history museum, demetrova 1, zagreb, croatia. 4. micropalaeontology 4.1. description of the new taxon phylum: foraminifera d’orbigny, 1826 class: globothalamea pawlowski et al., 2013 order: ataxophragmiina fursenko, 1958 superfamily: textulariacea ehrenberg, 1838 family:?valvulinidae berthelin, 1880 remarks: with its elongate test, trochospiral later becoming uniserial, the simple chambers, a paraporous wall structure, and probable cribrate apertural plate, cretaciclavulina is tentatively placed into the family valvulinidae berthelin, 1880. according to loeblich & tappan (1987, p. 181), the valvulinidae range in age from the palaeocene to the holocene. cretaciclavulina n. gen. type species: cretaciclavulina gusici n. gen., n. sp. origin of the name: composite name referring to the cretaceous and the genus clavulina d’orbigny. diagnosis: test elongate, trochospiral (most likely triserial) to uniserial, with a short intermediate biserial stage between these. chambers simple, broad low, enlarging in the triserial stage and of nearly constant width in the uniserial stage. wall thick agglutinating, and canaliculate (paraporous), possibly with an inner calcareous (?aragonitic) layer. foramen single interiomarginal in the trochospiral and areal in the uniserial part. aperture areal, provided with a cribrate apertural plate. remarks: the wall structure combined with the elongate test and its trochospiral to uniserial chamber arrangement allow a comparison of cretaciclavulina with some representatives of the family palaeotextulariidae galloway, 1933, valvulinidae berthelin, 1880, and partly also the ataxophragmiidae schwager, 1877, verneuilinidae cushman, 1911 as well as pseudogaudryinidae loeblich & tappan, 1985 (fig. 3a). the wall of cretaciclavulina displays closely spaced, fine and more or less parallel, more rarely bifurcating canaliculi or parapores that are not open to the exterior, but end blindly shortly g eo lo gi a c ro at ic a geologia croatica 69/2190 before the outer test surface (see banner et al., 1991; hottinger et al., 1990; hottinger, 2006, for details) (fig. 3a). this thin outer „pavement” is commonly eroded. canaliculi appear scarcer to absent in the septa. the phylogentic relationship concerned with the appearance of such „false keriothecae” (vachard et al., 2004) is still poorly understood and requires further study (see also rigaud et al., 2015). in the adult chambers of some cretaciclavulina the outline of an inner calcareous layer, morphologically close to that of the palaeotextulariidae (fig. 3b), is preserved. in palaeotextulariidae, however, the inner layer is clearly yellowish and fibrous whereas that observed in cretaciclavulina is recrystallized into sparite (?originally aragonitic). it is worth mentioning here that a yellowish inner fibrous calcitic layer was reported recently from the upper cretaceous (coniacian) genus siphodinarella (schlagintweit et al., 2014). axial sections (that usually do not allow bi se rial to be distinguished from the triserial forms) of cretaci­ clavulina show morphological resemblance to large-sized palaeozoic palaeotextulariid genera such as climacammina brady (fig. 4a), deckerella cushman & waters (fig. 4b), and palaeobiginerina galloway. these taxa are biserial becoming uniserial in the adult part. the wall structure is originally described as „calcareous, microgranular, commonly with an inner radial fibrous layer” (loeblich & tappan, 1987, p. 218). this view was corrected by piller (1990) evidencing the agglutinating character of the outer layer. the uniserial stage in cretaciclavulina does not abruptly follow the trochospiral (triserial) stage, but with a mediating short biserial stage. examples of such triserial-biserial-uniserial tests are for example the agglutinated lower cretaceous spiroplecti­ nata cushman, 1927 of the verneuilinidae (tyszka & thies, 2001; kaminski et al., 2011) and gerochella neagu, 1997 (fig. 4c) of the ataxophragmiidae, the eocene to holocene goesella cushman, 1933 of the valvulinidae (fig. 4d), as well as the late cretaceous (campanian) rectogerochammina kaminski, cetean & neagu, 2010 of the family prolixoplectidae loeblich & tappan, 1985. the four mentioned genera exhibit a solid (non-canaliculate) wall different from that of cre­ ta ciclavulina. forms with a serial and later uniserial test as well as a canaliculate wall structure are reported from the various representatives of the family valvulinidae berthelin, with the genera clavulina d´orbigny, 1826, cribrogoesella cushman, 1935, and gyrovalvulina loeblich & tappan, 1985 as well as of the family pseudogaudryinidae loeblich & tappan, 1985, with the genera clavulinopsis banner & desai, 1985, and pseudoclavulina cushman, 1936. the differences between these genera and cretaciclavulina can be roughly summarized as follows (only the main differences are stressed; ages and generic features acc. to loeblich & tappan, 1987): – clavulina d’orbigny, 1826 (palaeocene to holocene) (fig. 4e): triangular early and uniserial adult stage (3-1 chamber arrangement opposed to 3-2-1 in cretaciclavu­ figure 3. details of the wall structure of cretaciclavulina gusici n. gen., n. sp. a) detail from pl. 1d showing rare distal pore bifurcations (arrows). thin-section s2n124. b) detail from the holotype specimen of pl. 1a showing the inner recrystallized calcareous layer. thin-section 514 k3v71/5. figure 4. foraminiferal genera that are compared with cretaciclavulina n. gen. a) climacammina antiqua (brady), early carboniferous of scotland (from loeblich & tappan, 1987, pl. 228, fig. 11). b) deckerella clavata cushman & waters, late carboniferous of texas (from loeblich & tappan, 1987, pl. 229, fig. 3). ) gerochella cylindrica neagu, valanginian of romania (from neagu, 1997, fig. 1/40–41). d) goesella rotundata (cushman), holocene of philippine islands (from loeblich & tappan, 1987, pl. 200, fig. 6). e) clavulina parisiensis d´orbigny, middle eocene of france (from loeblich & tappan, 1987, pl. 200, fig. 3). f) cribrogoesella robusta (brady), holocene of pernambuco, atlantic (from loeblich & tappan, 1987, pl. 201, fig. 3), g) clavulinopsis hofkeri banner & desai, upper cretaceous (campanian) of texas, usa (from loeblich & tappan, 1987, pl. 196, fig. 3). h) bigenerina nodosaria d´orbigny, holocene of france (from loeblich & tappan, 1987, pl. 191, fig. 1). scale bars = 0.3 mm. g eologia c roatica felix schlagintweit and blanka cvetko tešović: cretaciclavulina gusici n. gen., n. sp. (?family valvulinidae berthelin, 1880) ... 191 lina; see also the comparative table in weidich, 1988); finely bifurcating pores are sealed internally by an organic lining (that may simply not be preserved in cretacicla­ vulina?); aperture with an imperforate toothplate; toothplates of successive chambers oriented 120 degrees apart. – cribrogoesella cushman, 1935 (miocene to holocene) (fig. 4f): early trochospiral stage with up to five chambers; rapidly reducing to three, then biserial and finally uniserial; both lateral walls and septa strongly canaliculate; aperture cribrate in the uniserial stage (opposed to single, and areal in cretaciclavulina). – gyrovalvulina loeblich & tappan, 1985 (eocene): „triserial and triangular early stage and later chambers in a loose spiral, with progressively fewer chambers per whorl, until the final chamber nearly completely encircles the axis” (loeblich & tappan, 1985, p. 213). – clavulinopsis banner & desai, 1985 (campanian to maastrichtian) (fig. 4g): test triangular (throughout!); early stage triserial, later abruptly becoming uniserial (3-1 chamber arrangement opposed to 3-2-1 in cretaciclavulina). – pseudoclavulina cushman, 1936 (upper cretaceous to lower eocene): early stage triangular, then uniserial (3-1 chamber arrangement) thereby reducing abruptly test diameter; aperture terminal, but without a distinct tooth. last but not least, the genus bigenerina d’orbigny, 1826 (eocene to holocene acc. to loeblich & tappan; 1987) shows an early biserial stage, later becoming abruptly uniserial, and an agglutinating, canaliculate wall (fig. 4h). it is worth mentioning here that the mesozoic-cenozoic taxa that were compared with cretaciclavulina were all described from isolated specimens recovered from deeper water marly litho logies. cretaciclavulina instead is reported from typical shallow-water platform carbonates. cretaciclavulina gusici n. sp. fig. 3, pl. 1 1990 unidentified or unknown foraminifera – gušić & jelska, pl. 15, figs. 8, 9. origin of the name: dedicated to ivan gušić (zagreb) for his contributions to the taxonomy of benthic foraminifera. the new taxon was also illustrated for the first time by gušić & jelaska (1990) (see synonymy). holotype: subaxial section illustrated in pl. 1, fig. a, and details in pl. 1, fig. g, and fig. 3b, thin-section inv. no. 10807 (514 k3v71/5). paratypes: specimens illustrated in pl. 1, figs. b–f, h–o (inv. no. 10808–10815). type-locality: on the east side of the otočac cove (northeast coast of the brač island). approximate coordinates: 43.352294on, 16.796578o (fig. 1). type-level: lower campanian; the highest levels of the gornji humac formation, (upper turonian–lower campanian), and the rasotica and lovrečina members (lower–middle campanian) in the pučišća formation) (fig. 2). diagnosis: being monospecific see diagnosis of genus. description: test elongate, trochospiral to uniserial. the early stage, rounded triangular (with concave sides), is most likely triserial as visible in transverse sections (pl. 1b) becoming increasingly rounded. in the specimen shown in pl. 1a, this stage amounts about ~40 % of the total test. the rounded void at the table 1. benthic foraminifera (selection) co-occurring with cretaciclavulina gusici. taxa thin-sections ac or di el la co ni ca fa ri n ac ci an ta ly na ko ra yi fa ri n ac ci & k ö yl ü o g lu ca lv ez ico nu s l ec al ve za e ca u s & co rn el la ca lv ez ico nu s? sp . cu ne ol in a gr . p av on ia p ar va h en so n d ic yc lin a sp . d ic ty oc on us ? s p. li tu on el la ? s p. li tu ol ip or a? n . s p. m ili ol id s m in ou xi a sp . m on tc ha rm on tia a pe nn in ica (d e ca st ro ) m ur ge lla la ta lu pe rt o s in n i ne zz az at in el la cf . a dh am i d ar m o ia n re tic ul in el la fl eu ry i c ve tk o e t a l. ro ta lis pi ra sc ar se lla i ( to rr e) sc an do ne a m ed ite rra ne a d e ca st ro sc an do ne a sa m ni tic a d e ca st ro vo lo sh in ov el la ? s p. 514 k3v71/5 x x x x x 251 5184 x x x x x 208 18/1s4 x x x x x x x x x x x x 223 187/1 s4 x x x x x x 1kr11315 ? ? x x x s2n124 x ? x x 209 18/2s4 x x x x x 132 918 ku3 x x x ? 21 42 1315kr1 x x x x x 212 728 s4 x x x x x x x x 528 k213 4615 x x x x mu 3k 606/20 x x x x x x x x ? x x g eo lo gi a c ro at ic a geologia croatica 69/2192 plate 1. cretaciclavulina gusici from the early campanian of brač island. a subaxial section, holotype specimen. thin-section inv. no. 10807 (514 k3v71/5). b slightly oblique transverse section showing triangular outline with concave sides, lower part of the triserial stage. thin-section inv. no. 10808 (223 187/1 s4). c slightly oblique transverse section in the upper part of the trochospiral stage (see gušić & jelaska, 1990, pl. xv, fig. 9). thin-section inv. no. 10809 (213 7218/2 s4). d slightly oblique section of the biserial stage. thin-section inv. no. 10810 (s2n124). e oblique section of the triserial stage. thin-section inv. no. 10811 (132 9184 ku3). f oblique section of the trochospiral stage. thin-section inv. no. 10812 (209 18/2s4). g detail from a, showing the transition of the triserial to the uniserial stage. note the pseudo-keriothekal wall structure. thin-section inv. no. 10807 (514 k3v71/5). h slightly oblique transverse section of the uniserial stage. thin-section inv. no. 10807 (514 k3v71/5). i detail from o, showing the cribrate apertural plate. thin-section inv. no. 10813 (1315/1kr1). j oblique section of the uniserial stage cutting two chambers. thin-section inv. no 10808 (223 187/1 s4). k subaxial section of a broken specimen cutting 8 chambers of the uniserial stage. thin-section inv. no. 10808 (223 187/1 s4). l broken fragment consisting of two chambers of the uniserial stage, axial section. thin-section inv. no. 10814 (208 18/1s4). m oblique or tangential section of a broken specimen cutting 4 chambers of the uniserial stage. thin-section inv. no. 10813 (1315/1kr1). n oblique section. thin-section inv. no. 10815 (21 42 1315kr1). o longitudinal, non-centered section of the uniserial stage, notably 9 chambers, of a specimen. the apertural detail is shown in i. thin-section inv. no. 10813 (1315/1kr1). g eologia c roatica felix schlagintweit and blanka cvetko tešović: cretaciclavulina gusici n. gen., n. sp. (?family valvulinidae berthelin, 1880) ... 193 apex of the holotype specimen possibly refers to the proloculus (fig. pl. 1g). altogether, the information on the initial stage is poor as most random sections are beyond the uniserial stage. further towards the following uniserial stage, transverse sections of the test become more and more rounded in outline (pl. 1b–e, g). a short biserial part occurs between the triserial and uniserial stages (pl. 1d). the adult stage is represented by a series of at least six uniserial chambers. this stage is roughly cylindrical, rectilinear to slightly bent, with chambers that only slightly increase in breadth and height. this accounts for the slender, sometimes slightly bent cylindroconical test morphology. transverse sections are either circular or slightly elliptical in outline. the solid septa are almost planar (so that the chambers are not overlapping) and pierced by a single foramen in a central to slightly eccentric position. in axial sections, the appressed chambers have a low rectangular shape with rounded margins. wall agglutinating, with a large amount of microgranular or microagglutinated calcareous material, thick and canaliculate (or paraporous) with fine pores (or canaliculi) ending blindly shortly before the outer test surface (fig. 3a). this thin outer layer (or „pavement”, see hottinger, 2006) is most ly eroded. the pores are straight and more or less parallel (radial arrangement), but may branch in the outer part. in the adult uniserial chambers of the holotype specimen, remnants of an inner calcitic layer are discernible. the thickness of this layer is about 0.04 mm at the lateral walls and is decreasing/tapering upon the septa towards the foramina (fig. 3b). foramen single interiomarginal in the trochospiral and areal in the uniserial part. aperture (last chamber) areal, provided with a cribrate apertural plate (pl. 1i). dimensions: test length: up to 2 mm test diameter: up to 0.7 mm number of chambers last mm axial length: 5 adult chamber height: ~0.18 to ~0.2 mm wall thickness (without calcitic inner layer): ~0.065 to ~0.1 mm diameter caniculi: ~7 µm remarks: cretaciclavulina gusici has been illustrated by gušić & jelaska (1990, pl. 15, figs. 8, 9) as an „unidentified or unknown foraminifera”. the two illustrations presented are a longitudinal section of the uniserial final part cutting nine chambers (op. cit., pl. 15, fig. 8, refigured here on pl. 1a, and detail in g). the other one represents an oblique transverse section of the triserial early portion (op. cit. pl. 15, fig. 9, refigured here on pl. 1c). based on these sections gušić & jelaska (1990) summarized the characteristics of this taxon comprising „a well-developed keriothecal wall structure, in addition to a comparatively simple morphology and lack of endoskeleton”. in fact, this material was insufficient for recognizing the new character of the form based on the combination of the different coiling modes in the early and late test portions. transverse sections of the chrysalidinid praechrysalidina infracreatcea luperto sinni, 1979 (aptian of south italy) (e.g., luperto sinni, 1985, pl. 6, fig. 5–6) are very similar to those of cretaciclavulina gusici. p. infracretacea differs from the latter mostly by having a triserially coiled test throughout. moreover, the early part of the test with its foramina are said to be most likely simple with broad apertural flaps situated at the inner margin, later becoming pierced by numerous areal pores (cribrate) opposed to the single areal foramina in cretacicla­ vulina (see also banner et al., 1991). the species gerochella cylindrica neagu (lower valanginian of romania, fig. 4c) can be considered homeomorphic to cretaciclavulina gusici, but is more slender (test length up to 1.4 mm; width between 0.24 to 0.29 mm). as already remarked, the wall of g. cylindrical is compact, finely agglutinated, whereas in cretaciclavulina the wall is canaliculate (paraporous). microfacies: cretaciclavulina gusici has been observed in packstones and grainstones containing a diverse association of benthic foraminifera: cuneolinids, orbitolinids, soritids and other miliolids, nezzazatids, coxitids, spirocyclinids, nautiloculinids, textulariaceans, rare rotaliids and others (tab. 1). acknowledgment the authors appreciate the very helpful and constructive comments of the two reviewers sylvain rigaud (singapore) and mike simmons (oxford). this work has been supported by the croatian science foundation under the project number ip-201409-9541. last but not least, we thank julie robson for the english corrections. references banner, f.t. & desai, d. (1985): the genus clavulinoides cushman emended and the new cretaceous genus clavulinopsis.– journal of foraminiferal research, 15, 79–90. doi: 10.2113/gsjfr.15.2.79 banner, f.t., simmons, m.d. & whittaker, j.e. (1991): the mesozoic chrysalidinidae (foraminifera, textulariacea) of the middle east: the redmond (aramco) taxa and their relatives.– bulletin of the british museum (natural history) geology, 47/2, 101–152. berthelin, g. (1880): mémoire sur les foraminifères fossils de l´etage albien de moncley (doubs).– mémoires de la société géologique de france, ser. 3, 1 (5), 1–84. checconi, a., rettori, r. & spalluto, l. (2008): biostratigrapfia a foraminiferei del cretaceo superiore della succession di parco priore (calcare di altamura, piattaforma apula, italia meridionale).– annali dell’universita degli studi di ferrara museologia scientifica e naturalistica, 4, 1–9. doi: 10.15160/1824-2707/4/1 cherchi, a., radoičić, r., schroeder, r., 1991. neobalkhania bignoti n. gen., n. sp., grand foraminifère du maastrichtian supérieur du sud-est de l´europe.– comptes rendus de l´ academie des sciences, série ii, 313, 287–292. cushman, j.a. (1911): a monograph of the foraminifera of the north pacific ocean. part ii – textulariidae.− united states national museum bulletin, 71, 1−108. doi: 10.5479/si.03629236.71.2 cushman, j.a. (1927): an outline of a re-classification of the foraminifera.– contributions from the cushman laboratory for foraminiferal research, 3, 1–105. cushman, j.a. (1933): some new foraminiferal genera.– contributions from the cushman laboratory for foraminiferal research, 9, 32–38. cushman, j a. (1935): fourteen new species of foraminifera.– smithonian miscellaneous collections 91 (21), 181, 1–9. doi: 10088/23898/smc_91 cushman, j.a. (1936): new genera and species of the families verneuilinidae and valvulinidae and of the subfamily virgulininae.– special publications cushman laboratory for foraminiferal research, 6, 1–71. cvetko, b., gušić, i., schroeder, r. (1997): reticulinella fleuryi n. sp. (foraminiferida) from the upper cretaceous (upper santonian–middle campanian of the island of brač, croatia.– revue de micropaléontologie, 40/2, 131–139. doi:10.1016/s0035-1598(97)90530-4 cvetko tešović, b., gušić, b., jelaska, v., bucković, d. (2001): stratigraphy and microfacies of the upper cretaceous pučišća formation, island of brač, croatia.– cretaceous research, 22, 591–613. doi: 10.1006/cres.2001.0279 davey, s.d. & jenkyns, h.c. (1999): carbon-isotope stratigraphy of shallow-water limestones and implications for the timing of late cretaceous sea-level rise and anoxic events (cenomanian-turonian of the peri-adriatic carbonate platform, croa tia).– eclogae geologicae helvetiae, 92, 163–170. doi: org/10.5169/seals-168658 de castro, p. (1974): su alcune nuove miliolidi del senoniano del mediterraneo.– vi instituto di paleontologia dell´università di napoli pubblicazione, 54, 1–19. de castro, p., drobne, k. & gušić, i. (1994): fleuryana adriatica n. gen., n. sp. (foraminiferida) from the uppermost maastrichtian of the brač island (croatia) and some other localities on the adriatic carbonate platform.– razprave iv. razreda sazu, 35/8, 129–149. d’orbigny, a. (1826): tableau méthodique de la classe des céphalopodes.– annales des sciences naturelles, 7, 245–314. frijia, g., parente, m., di lucia, m. & mutti, m. (2015): carbon and strontium isotope stratigraphy of the late cretaceous (cenomanian-campanian) shallow-water carbonates of southern italy: chronostratigraphic calibration of larger g eo lo gi a c ro at ic a geologia croatica 69/2194 foraminifera biostratigraphy.– cretaceous research, 53, 110–139. doi: 10.1016/j. cretres.2014.11.002 galloway, j.j. (1933): a manual of foraminifera. bloomington, principia press. gušić, i. & jelaska, v. (1990): upper cretaceous stratigraphy of the island of brač.– djela jugoslavenska akademija znanosti i umjetnosti zagreb, 69, 1–160. hottinger, l. (2006): illustrated glossary of terms used in foraminiferal research. carnets de géologie.– notebooks on geology memoires 2006/02. doi: cg2006_m02 hottinger, l., halicz, e. & reiss, z. (1990): partitions and fistulose chambers in textulariina.– in: hemleben, c., kaminski, m.a., kuhnt, w. & scott, d.b. (eds.): paleoecology, biostratigraphy, paleoceanography and taxonomy of agglutinated foraminifera. dordrecht, kluwer academic publisher, 37–49. doi: 10.1007/978-94-011-3350-0 jelaska, v. (2002): carbonate platforms of the external dinarides.– in: vlahović, i. & tišljar, j. (eds.): evolution of depositional environments from the palaeozoic to the quaternary in the karst dinarides and pannonian basin.– 22nd ias meeting of sedimentology, opatija, field trip guidebook, 67–71. jenkyns, h.c. (1991): impact of cretaceous sea level rise and anoxic events on the mesozoic carbonate platform of yugoslavia.– american association of petroleum geologists, bulletin, 75/6, 1007–1017. kaminski, m.a., cetean, c.g. & tyszka, j. (2011): nomenclature to describe the transition from multiserial to uniserial chamber arrangement in benthic foraminifera.– journal of micropalaeontology, 30, 7–10. doi: 10.1144/0262-821x10-016 kaminski, m.a., cetean, c.g. & neagu, t. (2010): rectogerochammina eu­ gubina nov. gen., nov. sp., a new agglutinated foraminifer from the upper cretaceous of gubbio, italy.– revue de micropaléontologie, 53, 121–124. doi:10.1016/ jraminifera korbar, t. (2003): stratigrafija, taksonomija i paleoekologija radiolitida gornje krede jadranske karbonatne platforme (stratigraphy, taxonomy and palaeoecology of upper cretaceous radiolitidae of the adriatic carbonate platform).– phd thesis, university of zagreb, croatia, 242 p. (in croatian with english summary, unpublished). korbar, t., glumac, b., cvetko tešović, b., cadieux, s. b. (2012): response of a carbonate platform to the cenomanian–turonian drowning and oae 2: a case study from the adriatic platform (dalmatia, croatia).− journal of sedi-sedi-edimentary research, 82, 163−176. doi:10.2110/jsr.2012/17 korbar, t. & husinec, a. (2003): biostratigraphy of turonian to (?)coniacian platform carbonates: a case study from the island of cres (northern adriatic, croatia).– geologia croatica, 56, 173–185. doi: 10.4154/gc.2003.11 loeblich, a.r., jr. & tappan, h. (1985): some new and redefined genera and families of agglutinated foraminifera ii.– journal of foraminiferal research, 15/3, 175–217. doi: 10.2113/gsjfr.15.3.175 loeblich, a.r., jr. & tappan, h. (1987): foraminiferal genera and their classification. – 2 volumes, 1–970, (van nostrand reinhold) new york. doi: 10.1007/9781-4899-5760-3 luperto sinni, e. (1976): microfossili senoniani delle murge.– rivista italiana di paleontologia e stratigrafia, 82/2, 293–416. luperto sinni, e. (1979): praechrysalidina infracretacea n. gen., n. sp. (foraminiferida) del cretaceo inferiore delle murge baresi.– studi geologici e morfologici sulla regione pugliese, 5, 1–16. luperto sinni, e. (1985): praechrysalidina infracretacea luperto sinni, 1979. – in: schroeder, r. & neumann, m. (coords.), les grand foraminifères du crétacé moyen de la région méditerranénne.– géobios mémoire spécial, 7, 22. neagu, t. (1997): lower cretaceous agglutinated foraminifera from southern dobrogea, omania. part 1, verneuilinacea, ataxophragmiacea.– annales societatis geologorum poloniae, 67, 307–323. pamić, j., gušić, i. & jelaska, v. (1998): geodynamic evolution of the central dinarides.– tectonophysics, 297, 251–268. doi: 10.1016/s0040-1951(98)00171-1 pejović, d. & radoičić, r. (1987): contribution to the study of upper cretaceous stratigraphy of brač – adriatic carbonate platform.– geologija, 28/29, 121–150 (in serbian, english summary). piller, w.e. (1990): wall structures of palaeotextulariid foraminifers and discussion of microgranular test walls.– paleoecology, biostratigraphy and taxonomy of agglutinated foraminifera. nato asi series, 327, 25–35. doi: 10.1007/978-94-0113350-0_4 polšak, a., bauer, v. & slišković, t. (1982): stratigraphie du crétacé supérieur de la plate-forme carbonatée dans les dinarides externs.– cretaceous research, 3, 125–133. doi: 10.1016/0195-6671(82)90013-1 rigaud, s., vachard, d. & martini, r. (2015): agglutinated versus microgranular foraminifers: end of a paradigm?– journal of systematic palaeontology, 13/2, 75–95. doi:10.1080/14772019.2013.863232 schlagintweit, f., husinec, a. & jež, j. (2014): siphodinarella costata n. gen., n. sp., a new benthic foraminifer from the upper cretaceous (late turonian-santonian) of the karst dinarides (slovenia, croatia).– facies, 60, 133–145. doi: 10.1007/s10347-013-0365-1 schwager, c. (1877): quadro del proposto sistema di classificazione dei foraminiferi con guscio.– bolletino del r. comitato geologico d´italia, 8, 18–27. steuber, t., korbar, t., jelaska, v. & gušić, i. (2005): strontium-isotope stratigraphy of upper cretaceous platform carbonates of the island of brač (adriatic sea, croatia): implications for global correlation of platform evolution and biostratigraphy.– cretaceous research, 26, 741–756. doi: 10.1016/j.cretres.2005.04.004 torre, m. (1966): alcuni foraminiferi del cretacico superiore della penisola sorrentina.– bolletino della società dei naturalisti in napoli, 75, 409–431. tyszka, j. & thies, a. (2001): spiroplectinata, key benthic foraminifera genus for palaeoceanographic reconstructions of the albian lower saxony basin.– palaeogeography, palaeoclimatology, palaeoecolgy, 174, 199–220. doi: 10.1016/s00310182(01)00294-2 vachard, d., munnecke, a. & servais, t. (2004): new sem observations of keriothecal walls: implications for the evolution of the fusulinida.– journal of foraminiferal research, 34/3, 232–242. doi: 10.2113/34.3.232 velić, i., (2007): stratigraphy and palaeobiogeography of mesozoic benthic foraminifera of the karst dinarides (se europe).– geologia croatica, 60, 1–113. doi: 10.4154/gc.2007.01a vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeography, palaeoclimatology, palaeoecology, 220/3–4, 333–360. doi: 10.1016/j.palaeo.2005.01.011 weidich, k.-f. (1988): on the variability of some recent and fossil „clavulina” species (foraminifera). abhandlungen der geologischen bundesanstalt, 41, 337–354. 2017 | 70/2 | 79–85 | 7 figs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society possibilities for well log correlation using standard deviation trends in neogene-quaternary sediments, sava depression, pannonian basin marko cvetković university of zagreb, faculty of mining, geology and petroleum engineering, zagreb; (marko.cvetkovic@rgn.hr) doi: 10.4154/gc.2017.07 abstract the regular working method for well log correlation in the neogene-quaternary infill of the croatian pannonian basin is based on visual identification of specific motifs that can be observed regionally through the sub-basins or depressions. this method is proven successful through exploration for petroleum accumulations in the aforementioned area but its application is limited outside of the interval of the upper miocene sediments and has proven to be subjective. standard deviation values of well log data from conventional well logs (spontaneous potential, shallow and deep resistivity) were calculated and observed over the entire neogene-quaternary well interval for defining new correlation markers which correspond to the old well log marker horizons. traditionally determined marker horizons did not coincide with those defined by the standard deviation technique. however, new regional horizons were established in the youngest part of the infill, which made more detailed correlation now possible. be observed on well log curves, more specifically on the resisti­ vity curves in thick­bedded marls (vrbanac, 2002). this method is valid when the sedimentary environment is large enough to support the formation of such layers that can be distin­ guished regionally. in smaller and/or more dynamic environ­ ments, a different kind of approach has to be employed to be able 1. introduction subsurface settings and stratigraphic relations of the croatian part of the pannonian basin (cpbs) have traditionally been di­ vided into formations and members based on research that is on­ going from the 1950s. these strata are generally divided by well log marker horizons, which represent distinctive motifs that can article history: manuscript received january 31, 2017 revised manuscript accepted may 05, 2017 available online june 28, 2017 keywords: standard deviation trends, marker horizon, correlation, sava depression, pannonian basin figure 1. extent of the exploration area with indicated well locations (from cvetković, 2016). g eo lo gi a c ro at ic a geologia croatica 70/280 to regionally correlate deposits in the subsurface. for this pur­ pose, a mathematical approach using cumulative standard devia­ tion curves was tested on well data from the neogene – quater­ nary infill part of the sava depression, and pannonian basin (fig. 1). testing was performed initially on the entire neogene – qua­ ternary sediments and later focused on the youngest part – the pliocene, pleistocene and holocene. 2. general subsurface geological settings and previous research stratigraphic subdivision of the neogene­quaternary infill of the cpbs has been performed since the 1950s when the exploration for hydrocarbons began. this subdivision was based on a lithostratigraphical subdivision for each depression in the cpbs. the area of focus for this investigation is the sedimentary infill in the sava depression. the neogene­quaternary succession in the sava depression has been subdivided into six formations with their lithology described in detail in pletikapić (1969), šimon (1973, 1980), velić et al. (2002); saftić et al. (2003), velić (2007) and which can be generally observed in fig. 2. these formations (and members within) are separated by well log marker horizons that are traditionally treated as chrono­ horizons. a traditional approach for determining the position of the well log horizon is the selection of the distinctive motifs on well log curves, which could be tracked on adjacent wells. well log horizons can be conformable, unconformable or can have a dual character; e. g. conformable in the mid part of the depres­ sion while unconformable in the marginal areas. conformable horizons are located within the thick marl layers and it is pre­ sumed that these characteristic motifs are the results of minor granulometry changes in marls as a response to environmental influences (vrbanac, 2002). according to vrbanac (2002) they not only represent a border between lithostratigraphic units but could also serve as chronohorizons as vrbanac (2002) presumed that the environmental influences should be simulta­ neous depression/basin wide. these kind of well log horizons are regionally limited to late miocene intervals which had a large accommodation area and a dominant source of clastic ma­ terials (vrbanac, 2002, lučić et al., 2001, grizelj et al., 2017). generally, well log marker horizons should at least be rec­ ognizable over a localized area (e.g. the size of a hydrocarbon ac­ cumulation) but the most usable ones are those that can be tracked throughout the depression. various sets of well log curves can be suitable, but the most common that are used for this purpose are the resistivity curves. these form part of the set of conventional electric well log curves that are acquired over the entire well in­ terval unlike other more costly well logging applications that are acquired mostly in limited well intervals, and only in the sus­ pected zone of interest. as mentioned in the introduction, well log horizons in cpbs have been distinguished in the whole neogene sequence of sedi­ ments with an emphasis on the upper miocene clastic infill. tra­ ditionally used regional well log marker horizons that are valid for sava depression are: tg/pt (unconformity) – boundary between neogene infill and cenozoic sedimentary rocks (pt) or magmatic and metamor­ phic rocks of mesozoic or palaeozoic age (tg). rs7 (dual character) – approximate boundary between mid­ dle and upper miocene sediments or boundary between prečec and prkos formations. rs5 (dual character) – boundary between the lower and up­ per pannonian according to vrbanac (2002) or the boundary between the prkos and ivanić­grad formations. z’ (conformable) – boundary between the upper pannonian and lower pontian (sensu lato as the existence of the pontian as in eastern paratethys is questionable, ćorić et al., 2009) accor­ ding to vrbanac (2002) or between the ivanić­grad and kloštar ivanić and široko polje formations. rf (conformable) – boundary between the lower and upper pontian (sensu lato) sediments or the kloštar ivanić and široko polje formations. figure 2. chronostratigraphic and lithostratigraphic units valid for the sava depression (from podbojec & cvetković, 2016 based on šimon, 1980, rogl, 1996, velić, 2002, ćorić et al., 2009). g eologia c roatica cvetković m.: possibilities for well log correlation using standard deviation trends in neogene-quaternary sediments, sava depression, ... 81 a’ (dual character) – boundary between miocene and plio cene sediments according to šimon (1980), velić (2002), cvet ko­ vić (2013) or the boundary between the široko polje and lonja formations. a methodology for locating well horizons (visual determi­ nation) has been applied from the earliest exploration and has proven to be successful as a large number of hydrocarbon fields and accumulations have been discovered utilizing this approach. this principle is valid worldwide although there were some suc­ cessful approaches to using geomathematics to determine well log horizons (luthi & bryant, 1997; lapkovsky et al., 2015). a downside of the traditional approach is that the method itself is quite subjective and is applicable only in large sedimen­ tary environments where similar conditions existed depression wide. this is a problem observed in more dynamic environments (cvetković, 2013, mandic et al., 2015, grizelj, et al., 2017, which existed prior to, and after the late miocene). to overcome these issues, a relatively simple mathematical method was employed for establishing a working method to dis­ tinguish horizons in wells in the aforementioned problematic in­ tervals – analysis of trends in curves of standard deviation (cst­ dev). these have been successfully tested on a limited dataset and on a single horizon (cvetković & malvić, 2013). 3. methods standard deviation (s) is a measurement of the dispersion of data values in relation to the mean data value (eq. 1) n1 2(x )in i 1 = −∑ = s m (1) whereas: n – number of cases in the observed dataset m – mean value of dataset xi – ith member of the dataset the goal of calculating standard deviation is to determine the amount of change in the environment, which relates to the change in values that can be observed in well log curves. the value of standard deviation in this case is dependent on two factors. firstly, well log data dispersion, which directly re­ lates to the lithological composition of the rocks (spontaneous potential logs and resistivity logs) and fluid within the rocks (re­ sistivity logs). the second factor is the radius (or window) of the observed interval or resolution of standard deviation sampling. as the first factor is constant, the influence of the radius interval was tested for three cases – one metre, two metre, and four me­ tres. the centre point interval is the data point for observation of standard deviation (stdev, fig. 3). all conventional electric well log (e­log) curves were initially subjected to stdev analysis (normalized spontaneous potential, spn; shallow resistivity, r16 and deep resistivity, r64). resistivity curves, in general, did not prove to be appropriate for stdev analysis (cvetković & malvić, 2013); so the focus was on the spn values. numerically, when observing standard deviation, the values less than 1 represent homogenous impermeable intervals (eg. marls and shales) between 1 and 5 for dominantly sandstone intervals, and more than 4 for thin layered marl­sandstone successions. for further emphasizing the stdev values for differentiating mono­ tonous marl intervals from dynamic environments, the standard deviation value was squared. in this way, the numerical value of stdev for marls being less than 1 was squared (stdev_r2) and smaller in reference to stdev values that were initially greater than 1. results of plotting these stdev and stdev_r2 values over a well interval shows the distribution of the data dispersion. the peak values can be used for defining lithological boundaries as they fall on the mid­point of the curve of inflexion. in this way, defining lithological boundaries is a less subjective process and can serve as a benchmark for training purposes as the correct pro­ cedure requires the boundary to be put on the mid­point of the in­ flexion of the curve (bassiouni, 1994, baker et al., 2015). values of standard deviation on a specific point as shown in fig. 4 represent only the dynamics of the environment in a single point, plotted over an entire well interval, but little information is revealed about the general dynamics. cumulative value curves of selected data have been previously used to depict trends in the subsurface, e.g. cumulative dip values were plotted along the depth axis of a well from dipmeter values (bengston, 1981; hurley, 1994; velić et al., 2009). in those instances the cu­ mulative value curves show a general trend in change of dip in­ figure 3. representation of the interval used for calculated stdev values in the case of 1, 2 and 4 metres. g eo lo gi a c ro at ic a geologia croatica 70/282 clination which could be related to the prevailing tectonic regime. a similar approach was performed with stdev values when plotted as a cumulative standard deviation curve (cstdev). ini­ tial testing was performed for defining the optimal resolution of stdev value to be plotted on a cstdev curve. testing was performed for one, two and four metre windows. the applicabil­ ity of each resolution window was tested by comparing it with a well log horizon which should indicate a great change in the sedi­ mentary environment when the large lake system was signifi­ cantly reduced and marsh environments occurred on a larger scale, e.g. in the case of a’ (cvetković, 2013, mandic et al., 2015). although curves of all three windows showed a break pat­ tern, the one metre version was most precise when compared to the data acquired from the initial well log horizon database (cvetković & malvić, 2013). as defining trends based on cstdev curves relies on visual determination, a square value of standard deviation was also plot­ ted as a cumulative curve (cstdev_r2). in this way, curves represent the general environmental dynamics where low incre­ ments of cumulative data value increases represent a small change in the environment and a high increment suggests a dy­ namic environment. squared values emphasize the low and high changes in the environment to an even greater extent. as a final step curves have to be normalized for the purpose of easier visualization. in contrast to plotting the cstdev and cstdev_r2 values which can differ significantly from well to well, values were plotted as a percentage of the maximum value on the axis (fig. 5). in this way, cross­correlation should prove more reliable as values of spontaneous potential for lithology can differ from well to well based on well logging conditions. 4. results analysis of cstdev and cstdev_r2 curves was performed on 43 wells in the sava depression (fig. 1). the first part of the figure 4. stdev and stdev_r2 values plotted against a thin-layered section (left) and a thick-layered section (right). figure 5. results of plotting cumulative standard deviation value curves of normal (cstdevn) and squared (cstdevn_r2) values of sp for the entire interval of well 1. g eologia c roatica cvetković m.: possibilities for well log correlation using standard deviation trends in neogene-quaternary sediments, sava depression, ... 83 analysis concerned the entire neogene­quaternary infill where regional well log marker horizons were plotted against calculated curves. several breaks in curve trends were present, but two dis­ tinctive ones can be correlated throughout the depression. un­ fortunately, only one of these breaks can be related to existing well log horizons, namely marker horizon a’ (boundary of the 2nd and 3rd intervals, fig. 6). the 1st interval defined by this break generally represents the prečec and prkos formations but can extend to even the kloštar ivanić formation (fig. 6, well 6). in general, sandstone layers are either thicker in this interval or absent, thus resulting in low stdev values and a low increment cstdev trend. a 2nd interval relates to a clastic infill of the ivanić­grad, kloštar ivanić and široko polje formations. sandstone layers are generally thicker than 10 m. several trends can be observed within this interval but those do not follow any of the well log marker horizons that are traditionally in use. unfortunately, seis­ mic cross sections were not available for testing the possibility of correlation in this interval. the 3rd interval belongs to thin layered (<5 m) clays and sands which are poorly sorted. frequent lithology changes re­ sulted in steep gradients in the cstdev curves. the basal boundary of the interval is well defined and marked by a break in the cstdev curve which coincides with regional well log marker horizon a’. the second part of the analysis focused only on sediments of the lonja formation (3rd interval; approximate age interval – plio­ cene, pleistocene and holocene). three distinctive trends were observed on cstdev curves in a confined interval (fig. 7). these breaks could be tracked through the entire research area. the cstdev_r2 curve showed too much sensitivity to change in the spn values which resulted in many trends that could not be correlated on a larger scale. thus, for further re­ search, a less sensitive parameter for observation in the data trend could be employed such as the median absolute deviation (mad) as in fedor et al. (2002). these trend breaks served as boundaries that define mem­ bers in the lonja formation on which the infill of the youngest formation in the sava depression was subdivided and subse­ quently mapped (cvetković, 2013). furthermore, the position of a’ horizon was adjusted on several positions based on cst­ dev curves to reflect the change in lithology. 5. conclusions observation of standard deviation values and trends on a cumu­ lative curve plot has proven to be of significant value. plotting stdev values against e­log curves during the initial part of the lithological analysis can help the interpretation in positioning the boundaries between different lithologies as maximum values fall onto a mid­point of the curve inflexion. in this way, an objective figure 6. relation of well log horizons determined by traditional methods and general trends by cstdev curves. g eo lo gi a c ro at ic a geologia croatica 70/284 parameter can be introduced in well log analysis rather than put­ ting the approximate location based on experience or using cutoff values for lithology, which can differ due to the nature of acquir­ ing the well log (e.g. water composition and salinity of the forma­ tion waters in contrast to mud properties). observing trends and break points in cstdev and cst­ dev_r2 curves did not show relationships with existing well log marker horizons, which makes their applicability in the upper miocene sediments questionable. this should be further tested against seismic stratigraphy to be either dismissed or further in­ vestigated. a distinctive break is present at the base of the lonja forma­ tion on both cstdev curves, which can be related to the a’ well log marker horizon. furthermore, two distinctive breaks within the lonja formation can be located on the cstdev curve that can be tracked throughout the depression. the cstdev_r2 curve in this instance showed too many breaks in trends (aka noise) and as a result, the two well marker horizons, which could be clearly seen with the cstdev approach, were obscured. this additionally raises the question of testing statistical analysis which are less sensitive to extreme values in the dataset (e.g. mad analysis) as a path for further analysis. based on the presented data, the cstdev curves proved to be valuable for correlating the well logs in intervals within thin­ layered successions in which regional well log marker horizons are absent due to the more restricted depositional environments. acknowledgment the author would like to thank lloyd’s register for donating ac­ ademic licenses of interactive petrophysics and schlumberger for donating academic licenses of petrel to university of zagreb, faculty of mining, geology and petroleum engineering without which this material would not be possible to be produced in its full extent. the publication process is supported by the development fund of the faculty of mining, geology and petroleum engineer­ ing, university of zagreb. references baker, r.o., yarranton, h.w. & jensen, j.l. (2015): openhole well logs­log interpretation basics.– in: yarranton, h.w., baker, r.o. & jensen, j.l. (eds.): practical reservoir engineering and characterization, elsevier, 534, 297–343. doi: 10.1016/b978­0­12­801811­8.00009­2 bassiouni, z. (1994): theory, measurement, and interpretation of well logs.– soci­ ety of petroleum engineers, richardson, 372 p. bengtson, c.a. (1981): statistical curvature analysis techniques for structural in­ terpretation of dipmeter data.– aapg bull., 65/2, 312–332. cvetković, m. (2013): naftnogeološki potencijal i litostratigrafska razradba trećega neogensko­kvartarnoga megaciklusa u savskoj depresiji [lithostratigraphic units of the third neogene-quarternary megacycle in the sava depression and their petroleum potential – in croatian with an english abstract].– unpubl. phd thesis, university of zagreb, faculty of mining, geology and petroleum engineering, zagreb, 175 p. cvetković, m. (2016): modelling of maturation, expulsion and accumulation of bac­ terial methane within ravneš member (pliocene age), croatia onshore.– open geosci., 8, 5–13. doi: 10.1515/geo­2016­0002 cvetković, m. & malvić, t. (2013): defining electro­log markers in poorly con­ solidated, heterogeneous clastic sediments using standard deviation data trends – an example from the sava depression, pannonian basin system.– in: horváth, j., wágenhoffer, a., geiger, j., cvetković, m. & malvić, t. (eds.): 16th hungarian & 5th croatian and hungarian congress abstract and program book. hungarian geology society & ina oil industry plc., szeged. doi: 10.13140/2.1.3191.0409 ćorić, s., pavelić, d., rögl, f., mandic, o., vrabac, s., avanić, r., jerković, l., & vranjković, a. (2009): revised middle miocene datum for initial marine flooding of north croatian basins (pannonian basin system, central paratethys).– geol. croat., 62/1, 31–43. doi: 10.4154/gc.2009.03 figure 7. positioning well log horizons (j’ and k’) within the lonja formation and a’ based on trend line (green) intersections. g eologia c roatica cvetković m.: possibilities for well log correlation using standard deviation trends in neogene-quaternary sediments, sava depression, ... 85 grizelj, a., peh, z., tibljaš, d., kovačić, m. & kurečić, t. (2017): minera­ logical and geochemical characteristics of miocene politic sedimentary rocks from the south­western part of the pannonian basin system (croatia): implications for provenance studies.– geoscience frontiers, 8, 65–80. doi: 10.1016/j.gsf.2015.11.009 ferenc, f., fegycerneki, s., hámór­vido, m. & lövei, j. (2001): a possi­ ble way of statistical analysis at small sample size.– in: lakatos, i. (eds.): novelties in enhanced oil and gas recovery. akadémiai kiadó, budapest, 1–14. hernitz, z., velić, j., kranjec, v. & najdenovski, j. (1980): prikaz dife­ rencijalnih i maloamplitudnih struktura s primjerima iz savske potoline (panonski bazen) [diferential and small amplitude structures examples from sava depression (pannonian basin) – in croatian].– nafta, 7–8, 399–409. hurley, n.f. (1994): recognition of faults, unconformities and sequence boundaries using cumulative dip plots.– aapg bull., 78/8, 1173–1185. lapkovsky, v.v., istomin, a.v., kontorovich, v.a. & berdov, v.a. (2015): correlation of well logs as a multidimensional optimization problem.– russ. geol. geophys., 56/3, 489–492. doi: 10.1016/j.rgg.2015.02.009 luthi, s.m. & bryant, d. (1997): well­log correlation using a back­propagation neural network.– math. geol., 29/3, 413–425. doi: 10.1007/bf02769643 mandić, o., kurečić, t., neubauer, t.a. & harzhauser, m. (2015): strati­ graphic and palaeogeographic significance of lacustrine molluscs from the pliocene viviparus beds in central croatia.– geol. croat., 68/3, 179–207. doi:10.4154/ gc.2015.15 pletikapić, z. (1969): stratigrafija, paleogeografija i naftoplinonosnost ivanić­grad formacije na obodu moslavačkog masiva [stratigraphy, palaeogeography and petroleum geology of ivanić-grad formation on the edge of moslavačka gora mt. – in croatian].– unpubl. phd thesis, university of zagreb, faculty of mining, ge­ ology and petroleum engineering, zagreb, 71 p. podbojec, m. & cvetković, m. (2016): preliminary estimate of co2 storage ca­ pacity by petrophysical modelling in upper miocene poljana sandstones in the western part of the sava depression.– the mining­geology­petroleum engineer­ ing bulletin, 31/1, 31–44. doi: 10.17794/rgn.2016.1.3 rögl, f. (1996): stratigraphic correlation of the paratethys oligocene and miocene. – mitteilungen ges. geol. bergbaustudenten österreich, 41, 65–73. saftić, b., velić, j., sztanó, o., juhász, g. & ivković, ž. (2003): tertiary subsurface facies, source rocks and hydrocarbon reservoirs in the sw part of the pannonian basin (northern croatia and south–western hungary).– geol. croat., 56/1, 101–122. doi: 10.4154/232 šimon, j. (1973): o nekim rezultatima regionalne korelacije litostratigrafskih jedinica u jugozapadnom području panonskog bazena [results of regional well log correlation of lithostratigraphic units in southwestern part of pannonian basin – in croatian].– nafta, 24/12, 623–630. šimon, j. (1980): prilog stratigrafiji u taložnom sustavu pješčanih rezervoara sava­ grupe naslaga mlađeg tercijara u panonskom bazenu sjeverne hrvatske [an addition to the stratigraphy of the sedimentary system of sandstone reservoirs of sava group in younger tertiary in pannonian basin of the northern croatia area – in croatian].– unpubl. phd thesis, university of zagreb, faculty of mining, geol­ ogy and petroleum engineering, zagreb, 66 p. velić, j., weisser, m., saftić, b., vrbanac, b. & ivković, ž. (2002): pe­ troleum­geological characteristics and exploration level of the three neogene de­ positional megacycles in the croatian part of the pannonian basin.– nafta, 53/6–7, 239–249. velić, j., malvić, t., cvetković, m. & bošnjak, m. (2012): statistical analysis of dipmeter logs from exploration wells in the drava depression, northern croatia.– journal of petroleum geology, 35/4, 343–356. doi: 10.1111/j.1747­5457.2012.00534.x vrbanac, b. (2002). facies and facies architecture of the ivanić­grad formation (late pannonian)­sava depression, nw croatia.– geol. croat., 55/1, 57–77. doi: 10.4154/gc.2002.06 benac.indd 239 � ab stra ct results of landslide monitoring undertaken between 1998–2010 on the north-eastern slope of the central part of rječina valley in front of grohovo village (north-eastern coastal part of adriatic sea, croatia) are presented. this is the largest regional active landslide. the slopes around the rječina riverbed are formed in siliciclastic sedimentary rocks with fl ysch characteristics. the bedrock is mostly covered with unstable slope formations. a limestone rock mass is visible on the cliffs around the top of the river valley. the landslide is complex and retrogressive, with 13 slid ing bodies. it occurred in december 1996 by displacement of an initial landslide body where movement had been registered in the 19th century. the limestone mega-blocks and separated rocky towers on the top of the slope have also moved, which is an atypical phenomenon of the fl ysch slopes in the area of rijeka. after initial sliding ceased, and major movements subsided, monitoring of benchmark movements from 1998 until 2010 determined further maximum displacements on the upper part of the slope, and minimum movement in the lower part. the area of the rje čina valley from the valići dam to the pašac bridge was selected as a pilot area in the framework of the croatianja panese bilateral joint research project. monitoring results provided the basis of establishing an early warning system for possible landslide occurrence and estimating the degree of landslide risk. keywords: landslide, fl ysch, karst, displacement, monitoring a complex landslide in the rječina valley: results of monitoring from 1998–2010 � čedomir benac1, sanja dugonjić1, martina vivoda1, maja oštrić2 and željko arbanas1 1 faculty of civil engineering, university of rijeka, v. cara-emina-5, 51 000 rijeka, croatia 2disaster prevention research institute kyoto university, gokasho, uji, kyoto 611-0011 doi: 104154/gc.2011.20 geologia croatica 64/3 239–249 12 figs. zagreb 2011 geologia croaticageologia croatica 1. introduction the rječina river fl ows through three different geomorphological zones. the fi rst occupies the area from the river source at the foot of the gorski kotar mountains to the lukeži village. the second zone extends from lukeži village to the canyon entrance near the pašac bridge, while the third stretches from the entrance of the canyon and the alluvial plain near the river mouth in the centre of rijeka city. the part of the valley between valići reservoir and the pašac bridge (situated at the entrance to the canyon (fig. 1)), is the most unstable part of the broad rijeka region, with a high degree of geohazard risk (benac et al., 2005b). a few mass movement phenomena have been noted since the end of the 19th century (anon, 2011) (fig. 2). different types of mass movements can be distinguished including the slippage of slope deposits over the fl ysch bedrock, rockfalls from limestone cliffs and the slippage of rocky blocks larger than 200 m3. these phenomena prevail on the northeastern slopes, but are relatively rare on the southwestern slopes of the rječi na – sušačka draga and bakar bay – vinodol valleys morphostructural unit (benac et al., 2009). geologia croatica 64/3geologia croatica 240 figure 1: simplifi ed geological map of the rječina catchment area (according to velić & vlahović, 2009): 1 – karstic terrain, 2 – palaeogene siliciclastic sedimentary rocks. the slopes in the rječina valley between the valići reservoir and the pašac bridge are at the limit of a stable equilibrium state. the investigated landslide area is not a recent phenomenon. mass movements were recorded in 1885 after which the, initial landslide body probably moved several times (magaš & palinić, 1999). the investigated landslide is situated on the north-eastern slope of the rječina valley (fig. 3 and 6). the last mass movement was observed on december 5th 1996. damming of the rječina riverbed was a secondary effect of the movement. after the initial landslide displacement, there was a retrogressive development from toe to head, as well as the formation of smaller landslides. at the end of the process, isolated rocky blocks were moved, and fractures on the slope head opened (benac et al. 1999; 2005a). further slippage has taken place in stages ever since and has not yet ended, so small mass movements, together with the opening of new fractures in the talus material and rockfalls from limestone ridges have been observed. this is the biggest known active landslide in the adriatic coast and is located in the unstable zone with numerous signs of dormant landslides. the dynamics and complexity of the whole phenomena was determined by analysis of move ments that were monitored between 1998–2010. the area of the rječina valley described from the valići dam to the pašac bridge, was selected as one of the pilot areas in the croatian-japanese bilateral joint research project „risk identifi cation and land-use planning for disaster mitigation of landslides and floods in croatia” (mihalić et al., 2010). a major part of the monitoring equipment will be installed in the active landslide zone on the north-eastern figure 2: a view of investigated zone of the rječina valley (photo: arbanas, ž.) benac et al.: a complex landslide in the rječina valley: results of monitoring from 1998–2010 geologia croatica 241 slope of the rječina valley, and some on the opposite, southwestern slope. all equipment will have a continuous comprehensive monitoring capability, and the data will be exported to the central computer unit of the faculty of civil engineering at the university of rijeka. an early warning system for possible landslide occurrence and degree of landslide risk will be established based on the monitoring results. these continuous real-time monitoring results will be used to determine threshold values of triggering factors including rainfall intensity and seismic activity. 2. morphology, hydrology and geology of the studied area the tectonic structure that includes the studied part of the rječina valley is part of a dominant morphostructural unit which strikes in the direction of the rječina – sušačka draga – bakar bay – vinodol valleys (velić & vlahović, 2009) (fig. 1). this geologic structure could be considered as a fl ysch syncline limited by faults, analogous with the tectonic style of the vinodol valley (blašković, 1999). tectonic interpretation of the rječina valley has not yet been performed. given the different morphological characteristics and the intensity of the geomorphological processes operating in the area, there are probably signifi cant differences com pared to the vinodol valley. the rječina watercourse is 18.7 km long with the river mouth located in the centre of rijeka city (fig. 1). rječina is a typical karstic river, originating from a strong karstic spring located at the foot of the gorski kotar mountains. the annual average fl ow of the rječina spring is 7.76 m3s–1, with maximum fl ow rates ranging from 0–100 m3s–1 (kaleuša et al., 2003). the rječina river has few tributaries, the most important of which is the sušica river. the sušica river is a west? bank tributary with an annual average fl ow of 0.72 m3s–1. although dry for most of the year, the maximum fl ow rate of the sušica can reach 43.8 m3s–1. part of the water balance from the rječina spring is used for the water supply of rijeka, while part of the water from the valići reservoir is used for electric power production in the rijeka hydropower plant of rijeka. the aforementioned part of the rječina valley between the valići reservoir and the pašac bridge has an uneven morphology, about 3 km in length and from 0.8 to 1.5 km in width trending nw–se. the bottom of the valley is 150 to 200 m above sea level. the peaks reach the height of 432 m in the south-western and 412 m in the north-eastern part of the valley (fig 3). the kinematics of the structural elements of this part of the rječina valley, as in the morphostructural unit mentioned above, are based on the relationship between the relatively rigid carbonate rocks and relatively ductile siliciclastic rocks during simultaneous deformation. the cretaceous and the palaeogene limestones are situated on the top of the slopes, while the palaeogene siliciclastic rocks or fl ysch are located on the lower slopes, including the bottom of the valley (figs. 4 & 5). the flysch complex is a block squeezed between the limestone rock complex to the north-east and south-west. the effects of deformations are most distinctive on the contact between the two rock complexes. this explains why the relatively rigid limestone rock mass is pushed into a more ductile siliciclastic rock. in this way, a former straight line tectonic contact, could have taken on the present toothed appearance (blašković, 1999; benac et al., 2006). unlike limestone rocks on the top of the slope, the fl ysch rock mass is almost completely covered by weathered material, slope formation and talus deposits (fig. 5). sandstone layers, which are visible only on the outcrops of the rječina riverbed, have a dip of 10°–15° towards the northeast. figure 3: a map of rječina valley from 1894: l – position of investigated active landslide (anon, 2011). geologia croatica 64/3geologia croatica 242 the rock mass, as well as the accumulation of talus deposits at the foot of the rock cliffs (fig. 5). siliciclastic or fl ysch bedrock is characterized by great lithological heterogeneity, because of the frequent vertical and lateral alternation of different lithological sequences. microscopic petrological analysis of the bedrock has shown the presence of silty marl, laminated silt to silty shale, as well as fi ne grained sandstones (benac et al., 2005a). unlike the limestones, the fl ysch rock mass is more prone to weathering, resulting in a clayey weathering zone on the fl ysch bedrock. over time, coarse grained fragments originating from the rock falls were mixed with clay from the weathered fl ysch zone and slope deposits several metres thick were form ed (fig. 5). 3. landslide description field investigations were conducted in two phases. the fi rst phase included topographical (terrestrial photogrammetry) and geophysical (shallow seismic-refraction profi ling) surveying methods, as well as engineering-geological mapping of the slope. a second phase of investigation focused on the landslide body itself using fi ve supplementary seismic-refraction profi les, and seven investigation boreholes. inclinometers and deformeters were installed into two central boreholes and piezometers were built into the remaining fi ve. elec trical sounding in the mega-block movement zone ascertained the contact between the limestone mega block from the top of the slope and the fl ysch bedrock (benac et al., 1999; 2002). the results indicate the formation of a complex landslide with thirteen sliding bodies. boundaries between these bodies are mostly clearly visible and represent different types of mass movements (fig. 7). the thickness of the displaced material has been estimated from the geological mapping and geophysical surveys results, together with the position of the slip surfaces. the geometry of the total complex landslide is described according to the wp/wli suggested nomenclature for landslides (iaeg, 1990): – total length: l = 425 m; – length of the displaced mass: ld = 420 m; figure 4: simplifi ed geological map of the rječina valley: 1 – palaeogene limestone; 2 – palaeogene siliciclastic rock mass (fl ysch) mostly covered by slope deposits; 3 – rocky scarps; 4 – active investigated landslide; 5 – rječina river stream; 6 – geological cross-section (see fig. 5) neotectonic and recent tectonic movements, induced by subduction of the adriatic plate beneath the dinarides, caus ed irregular subsidence of the squeezed basal syncline and uplift of the surrounding terrain (korbar, 2009). during this process, the limestone rock mass was repeatedly fault ed and fractured. such tectonic movements and weathering processes enabled separation of the limestone blocks and their gravitational sliding on the fl ysch bedrock, disintegration of figure 5: geological cross-section of the rječina valley 1 – palaeogene foraminiferal limestone; 2 – palaeogene siliciclastics sedimentary rocks (fl ysch); 3 – slope deposits; 4 – alluvial sediments (assumed position); i – relatively stable rock mass; ii – separated megablock; iii – block slide; iv – dormant rock avalanche; v – active landslide benac et al.: a complex landslide in the rječina valley: results of monitoring from 1998–2010 geologia croatica 243 – length of the rupture surface: lr =405 m; – width of the displaced mass: wd = 200 m; – width of the rupture surface: wr = 200 m; – depth of the displaced mass: dd = 6–20 m; – depth of the rupture surface: dr = 6–9 (20) m; – total height (the height from the crown to the tip of the toe) dh = 165 m. the initial landslide body had been transported the furthest, observed from the range of displaced material in the rječina riverbed, and by the tilted trees. due to the magnitude of displacement (up to 20 m), the former relationship of deposits was completely disturbed. a failure surface was formed along the contact of the slope deposits and the fl ysch bedrock (fig. 8). landslides in talus deposits or colluvium extend to the foot of the limestone cliff near the top of the slope, and the material consists mostly of rocky fragments and blocks. there are visible scars in the head of some landslip bodies up to 10 m in height. lateral sliding bodies in soil-like materials were probably formed last. they are „typical” of landslides on fl ysch slopes. limestone mega-block movements, separated from the limestone rock mass, are special phenomena, atypical of the geodynamic processes on fl ysch slopes in the rijeka area. blocks are probably moving on the fl ysch bedrock (figs. 8 and 9). the contact with the rock mass beneath the cliff, as well as their boundaries is masked by talus deposits. there are many open fractures visible in the disintegrated mass of the limestone on the cliff. according to the accepted classifi cations, the investigated landslide is a complex composite and retrogressive landslide (skempton & hutchinson, 1969). movefigure 6: grohovo landslide on the north eastern slope of the rječina valley (photo: benac, č.). figure 7: engineering geological map of the landside 1 – carbonate bedrock (palaeogene foraminiferal limestone); 2 – slope deposits (silty clay and fragments, fragments and blocks) over palaeogene siliciclastic bedrock; 3 – recent alluvial sediments (pebbles and gravels); 4 – open fracture (scarp); 5 – shearing fracture; 6 – position of the toe of the landslide (december 1996); 7 – initial body of the landslide; 8 – assumed new body of the landslide; 9 – borehole (installed piezometer); 10 – borehole (installed inclinometer); 11 – trace of engineering geological crosssection (see fig. 8) geologia croatica 64/3geologia croatica 244 as well as the blocky slide type iiib (antoine & giraud, 1995). it could also be considered a reactivated landslide on unstable slope, type ib based on the sliding activity (crozier, 1984). the affected slope has distinctive fi ltration anisotropy. groundwater fl ow in cohesionless talus material is very rapid, in contrast to cohesive talus material, where infi ltration and water fl ow are very slow. subsurface groundwater can be accumulated locally in clayey to silty slope material and in the weathered bedrock zone. this water originates either from direct infi ltration of precipitation, or from the karst aquifer on the top and behind the slope. surface fl ow usually occurs in the cover overlying the contact with the impermeable fl ysch bedrock. groundwater discharges along the rječina channel (benac et al., 2005 a). the ground water level fl uctuates with rainfall. slope deposits could be totally saturated after a long rainy period and consequently, surface fl ow can appear. springs in the foot of the landslide are active even after longer dry periods. an ephemeral spring (active only in periods of intense precipitation) is located in the foot of the coarse-grained slope deposits (fig.7). 4. results of monitoring and the new monitoring system a monitoring system was set up for observation of further movements of the landslide body. after the 1st phase of investigation, sixteen benchmarks were placed on parts of the slope, around and on the landslide, and on the cliffs above. after the 2nd phase of investigation works, benchmarks were placed at all seven boreholes. combined casings for an inclinometer and a deformeter were installed in two boreholes (g-4 and g-6), in the central part of the landslide, piezometers were installed into another fi ve boreholes to facilitate observation of changes in groundwater levels (fig. 7). figure 8: engineering geological cross-section of the landslide. 1 – slope deposits; 2 – fl ysch (bedrock); 3 – limestone (bedrock); 4 – boundary of landslide; 5 – borehole; i – relatively stable rock mass; ii – separated mega block; iii – active landslide; iv – initial landslide note: the position of bedding in limestones is only symbolic figure 9: isolated rocky tower (photo: benac, č.) ments of mixed rock and soil material in the initial landslide body show characteristics of debris avalanches, according to their movement velocities (varnes, 1978; cruden, & varnes, 1996). block sliding of a rock mass is a special phenomenon. due to the fact that the position of the slip surface was predisposed by geological composition, the landslide can also be considered as a consequent translational, benac et al.: a complex landslide in the rječina valley: results of monitoring from 1998–2010 geologia croatica 245 observation of the benchmarks (r-1 to r-16) began in december 1998. benchmark r-14 was destroyed after installation. observation of the benchmarks at boreholes (g-1 to g-7) began in september 1999. topographic surveys were carried out from the base point on the opposite side of the rječina valley, from a distance of 1000 m. it was possible to measure horizontal displacement (x, y) with an accuracy of ± 1.0 cm, and vertical displacement (z) to ± 1.5 cm (benac et al., 2002; benac et al., 2005 a). measurements were conducted approximately every 2 to 3 months (4 to 6 times per year), shown as both trends, and total displacements (fig. 10). according to different rates of movement, the investigated slope could be subdivided into three zones, but without clearly visible boundaries. benchmarks (r-1 to r-5) located on the limestone mega-block, have a relative different horizontal downslope displacement (4 to 12 cm) and uniform subsidence (5 to 6 cm). benchmark r-1 is located on part of the mega-block separated by a tension crack, and it shows greater subsidence (10 cm) (fig. 9). benchmark r-10, located on the west isolated rocky block (tower), had the most rapid trend of horizontal downslope displacement, (8 cm), until it was destroyed. conversely, benchmark r-6, on the eastern rocky tower, had a relatively small horizontal displacement of 5 cm and a vertical one of 8 cm. benchmarks on the talus at the foot of the cliffs, and those on their eastern edge (r-7, r-8, r-9, r-11 and r-12) show the most distinctive trends of downslope displacement (25–32 cm), as well as subsidence (up from 8 to 19 cm). formation of a new slide body on this part of the slope is indicated by the presence of open fractures (figs. 10 and 11). benchmarks on the lower part of the slope (r-13, r-15 and r-16) as well as those at the boreholes (g-1–g-7), have relatively small horizontal displacements in different directions. however, higher benchmarks (g-5, g-6 & g-7), recorded relatively large vertical displacements (12–22 cm). the difference in subsidence of benchmarks (progress of vertical displacement on the z axis) is closely related to their location on the slope (fig. 12). an integrated geodetic and geotechnical monitoring system will be installed in the grohovo landslide as part of the research activities in the croatian-japanese bilateral project. geodetic monitoring will include observing geodetic benchmark (prism) displacements with a robotic total station, and displacements of gps points (rovers). in total, 25 geodetic prisms and 15 gps rovers are predicted. figure 10: map of total horizontal and vertical displacement of benchmark. 1 – position of toe of the landslide (december 1996); 2 – margin of landslide (open fractures); 3 – margin of landslide (shearing fractures); 4 – borehole with benchmark: 5 – benchmark; 6 – total horizontal displacement of benchmark (not at the scale of the map) figure 11: new open fracture on the higher eastern part of the slope (photo: benac, č.). geologia croatica 64/3geologia croatica 246 equipment for geotechnical monitoring will include vertical inclinometers and long span extensometers, pore pressure gauges, seismographs and rain gauges. this equipment will be installed in the area of the active landslide on the north-eastern slope of rječina valley. piezometers, inclinometers and vertical extensometers will be installed at three locations, two inside the central landslide body and one on the slope to the east. extensometers will be installed from the rječina riverbed all through the limestone blocks to the top of the slope. all monitoring equipment will be connected into a single unique comprehensive system with continuous real-time monitoring. this will enable real-time transmission to the control centre and provide a publicly available presentation of the measured data. such an early warning system based on real time transmission will enable landslide alerts to be issued if the measured values exceed defi ned limits of values at which possible hazards occur. the system can only be established through the local authority and related services which requires necessary cooperation between the researchers and local government. 5. discussion the rječina valley – sušačka draga valley – bakar bay – vinodol valley morphostructural unit has a consistent geological fabric (blašković, 1999),comprising a fl ysch sync line compressed between the limestone rocky blocks. mass movements are more frequent and more distinctive on the northeastern slopes in the unit. talus breccia and cohesive colluvium deposits, resulting from older morphogenetic phases, are also common in these zones (benac et al., 2009). in contrast, intensive mass movements are visible on both slo pes in the central area of the rječina valley (fig. 3 and 4). movement of carbonate blocks near the contact with the fl ysch zones is not a common phenomenon, but similar to phenomena observed in the alps (moser, 2002). for this reason, the investigated part of the rječina valley is probable young er than a large part of the aforementioned morphostructural unit. changes in topographic relief are due to neotectonic movements, as well as changes of the local base level, and the position of the rječina riverbed. this also explains differences in the degree of erosive capacity of the river. morphogenetic development mentioned above was probably not continuous, with periods of accumulation of deposits resulting in the formation of slopes varying from stable to potentially unstable (benac et al., 2002). for this reason, one of the possible causes of slope instabilities in the studied area of the rječina valley is probably the different geological setting of this part of the valley compared to most of the rest of the rječina valley – sušačka draga valley – bakar bay – vinodol valley unit. however, the tectonic features of this part of the rječina valley have not yet been explained in detail. secondly, recent intensive tectonic movements that caused the opening of the rječina canyon may also have resulted in slope instabilities. as a result of base level fall, the rječina river has been rejuvenated in its erosive capacity. talus breccias, indicative of older intensive morphogenetic phases during the pleistocene, are absent from the slopes of the study area, but occur more frequently in other parts of the morphostructural unit (blašković, 1999). therefore, it can be assumed that in the rječina valley, morphogenetic development is younger than in surrounding areas, resulting in intensive recent mass movements. lateral erosion of the riverbed, and simultaneous erosion of the foot of the slopes, are factors causing mass movements. historic data for the area of rijeka, record the occurrence of fl ood events, (some of which caused catastrophic damage), that are closely related to the timing of mass movements in the study area (anon, 2011). such catastrophic fl oods of the rječina river occurred 1849, 1852, 1853, 1883 and 1898 and 1899 (magaš & palinić, 1999). according to data from the croatian state archive in rijeka, the landslides appeared on the south-western slope in 1885 and 1898, and in 1893 on the north-eastern slope, at the location of the studied landslide. the area affected by mass movements is clearly visible on the map from 1894 (fig. 2). investigation of the whole area of the valley between valići reservoir and the downstream canyon entrance, reveals the presence of more dormant landslides, some of which were active during the 20th century (benac et al., 2005a; 2006). the infl uence of river erosion was reduced after completion of the rječina riverbed regulation in 1908. instability on the north-east slope is due to a reactivated figure 12: vertical displacement of benchmarks from december 1996 to june 2010 (positions of benchmarks as shown in fig. 10). benac et al.: a complex landslide in the rječina valley: results of monitoring from 1998–2010 geologia croatica 247 landslide, as shown by recorded historic activity. frequent rockfalls from the top of the limestone cliff accelerated the accumulation of potentially unstable deposits. topographic maps from 1981 and 1998 have shown chan ges in slope morphology (benac et al., 1999). observation of geodetic benchmarks from 1998–2010 highlighted displacements, not only in the part of the slope affected by slippage, but also the formation of a new landside body on the upper part of the slope, indicating further development of the landslide along the slope (fig. 6 and 8). the rječina valley is the epicentre of rijeka's seismic area, where earthquakes > m 6.0 have occurred during the last two millennia (herak et al., 1996; tomljenović et al., 2010). strong earthquakes could decrease the stability of the slopes, and may have caused mass movements, i.e. in slope deposits that are already unstable. this can be followed by separation and rockfalls from the scarp on the top of the slope. according to archive data, mass movements were registered on the slopes around the rječina river after the destructive earthquake of 1870 (epicentre near klana village), north-west of the rječina valley. since 1998, two relatively strong earthquakes occurred that could have been a major triggering factor: 2003, m 4.0, epicentre near viškovo; 2004, m 4.5 in the area of fužine (anon, 2010). however, the direct impact of earthquakes on slope movement cannot be established due to the relatively long period between the measurements. many researchers have found strong correlation between periods of intensive rainfall and landslide reactivation (hong et al., 2005; borgatti et al., 2006). there were very heavy periods of rainfall and extreme rainfall events (> 100 mm/day), during the 12 yr monitoring period. precipitation data was recorded at the meteorological station in rijeka, 3 km from the study location (rubinić et al., 2010). clay, with a relatively low permeability, underlies the coarse rocky talus in the cover. this is expressed by the low hydraulic conductivity, relatively low infi ltration of surface water, and a high run out coeffi cient. similarly infi ltration in the unsaturated part, together with water level rise, occurs relatively slowly, which infl uences the rate of increase in pore pressures and a decrease in strength from total to effective values. therefore, long rainy periods are crucial for landslide initiation, and all landslide appearances occurred after long periods of heavy rainfall. results analysis showed the variable velocity of the movement of benchmarks over time (fig. 12). the groundwater level in the piezometers, and displacements of benchmarks, were measured 4 to 6 times a year. although the measurements of groundwater level were adjusted for the rainy periods, it was still not possible to establish a correlation between rainfall amount and displacements. installation of mo nitoring equipment, (inclinometers, extensometers, pore pressure gauges, seismograph and rain gauges), and continuous monitoring will facilitate the measurement and establishment of any correlation between displacement triggers including earthquakes and rainfall events and any consequent movements initiated. an innovative technique for the remote assessment of ground displacements, based on radar interferometry, and implemented using ground-based instrumentation (gb-insar), has been tested in recent years on a number of selected case studies (antonello et al., 2004) especially with regard to its use for early warning (casagli et al., 2010). both gps and insar techniques provided complementary measurements, with the gps providing horizontal movement and insar providing vertical motion (yin et al., 2010). the system of integrated geodetic and geotechnical monitoring that will be installed in the wider landslide area should provide better quality of data. certainly, the continuous gathering of data should allow better correlation between the triggers and scale of new movements of the landslide body. 6. conclusions the grohovo landslide was formed in the rječina valley, with unstable slopes, and is the result of both complex geological composition and the dynamics of its morphological evolution. it is a complex thirteen individual landslide bodies, developed from the toe to the top of the slope. the initial landslide body moved fi rst and buried the rječina riverbed. sliding affected colluvial deposits from the sedimentary cover, and the slip surfaces were mostly predisposed by the morphology of the fl ysch bedrock. permanent rock fall from highly disintegrated scarps has played a role of adding to the colluvial deposits over time. this unstable phenomenon of the north eastern slope of the rječina valley is a reactivated landslide. various instabilities were registered in the 19th century in this part of the valley. frequent rockfalls from the top of the limestone cliff accelerated the accumulation of potentially unstable deposits. results of previous investigations and monitoring will determine remedial measures for unstable colluvial deposits above the fl ysch bedrock. according to slope stability analysis, sliding in the lower part of the slope could cause retrogressive development of the process upslope. therefore, it is necessary to make remedial measures for the lowest parts of the slope, which will increase the stability of the upper part. stabilization of rock toppling is practically impossible. some analyses indicate that remedial measures will be very expensive. it is necessary to prevent the infi lling (and therefore damming of the rječina river, because of the location of the city of rijeka 5 km downstream. this is the main risk of further sliding. accumulated water behind any such dam would be at risk of overfl ow, in the case of heavy rainfall resulting in rapid water level rise and/or subsequent overfl ow. after such a collapse, the water wave could cause fatalities and serious damage to infrastructure in the urban area of the city of rijeka at the mouth of the rječina river. in the upper part of the slope remedial measures could be applied at a later date, should further monitoring results indicate their necessity. according to different rates of movement, the investigated slope could be subdivided into three zones. benchmarks located on limestone mega-blocks, have a relatively different horizontal downslope displacement (4 to 12 cm) geologia croatica 64/3geologia croatica 248 and uniform subsidence (5 to 6 cm). benchmark r-1, located on the part of the mega-block split by a tension crack, has larger subsidence of 10 cm. benchmarks on the isolated rocky blocks (tower), have relatively small horizontal and vertical displacement. benchmarks on the talus at the foot of the cliffs and those on their eastern edge show the most distinctive trend of downslope displacements: 25 to 32 cm, as well as distinctive subsidence up from 8 to 19 cm. a new landslide body could be formed on this part of the slope. benchmarks on the lower part of the slope as well as those at the boreholes, have relatively small horizontal displacements in different directions. however, benchmarks placed at the higher borehole locations show relative large vertical displacements (12 to 22 cm). the difference in subsidence of the benchmarks (progress of vertical displacement on z axis) is evident. a system of integrated geodetic and geotechnical monitoring that will be established on the wider landslide area will provide better quality of data and enable the establishment of an early warning system. acknowledgment this paper is result of research activity under the projects 114-0822695-2568 of the ministry and science, education and sports, republic of croatia, and croatia-japan project „risk identifi cation and land-use planning for disaster mitigation of landslides and floods in croatia”. references anon (2010): earthquakes report, department for geophysics faculty of natural sciences and mathematics, zagreb, www.gfz.hr (in croatian). anon (2011): city of rijeka. technical department (1840–1918). state archive in rijeka (unpublished documents, in hungarian). antoine, p. & giraud, a. (1995), typologie des mouvements de versants dans un contexte.– bulletin iaeg, 51, 57–62. antonello, g., casagli, n., farina, p., leva, d., nico, g., sieber, a.j. & tarchi, d. (2004): ground-based sar interferometry for monitoring mass movements.– landslides, 1, 21–28. doi: 10.1007/s10346-003-0009-6. benac, č., arbanas, ž., jardas, b., kasapović, s. & jurak, v. (1999): complex landslide in the rječina river valley, faculty of mining-geology and petrology.– almanac, 11, 81–90. (in croatian). benac, č., arbanas, ž., jardas, b., jurak, v. & kovačević, s.m. (2002): complex landslide in the rječina river valley (croatia): results and monitoring.– in: ribar, j., stemberk, j. & wagner, p. (eds.): proceedings of the 1st european conference on landslides, prague, june 2002. a.a.balkema, lisse-abingdon-exton-tokyo, landslides, 487–492. benac, č., arbanas, ž., jurak, v., oštrić, m. & ožanić, n. (2005a): complex landslide in the rječina river valley (croatia): origin and sliding mechanism.– bulletin of engineering geology and the environment 64/4, 361–371. doi: 10.1007/s10064-0050002-5 benac, č., jurak, v. & oštrić, m. (2005b): qualitative assessment of geohazard in rječina valley, croatia.– geophysical research abstract, vol. 7, 08943, 1–6. benac, č., jurak, v. & oštrić, m. (2006): qualitative assessment of geohazard in the rječina valley, croatia. proceedings of the 10th iaeg international congress: iaeg engineering geology for tomorrow’s cities, 658 (1–7), the geological society of london. benac, č., dugonjić, s., arbanas, ž., oštrić, m. & jurak, v. (2009): the origin of instability phenomena along the karstflysch contacts.– in: vrkljan, i., (ed.): isrm international sym posium rock engineering in diffi cult ground conditions: soft rock and karst, october, 2009, cavtat. crc press, boca ratonlondon-new yorkleiden, 757–761. benac, č., dugonjić, s., oštrić, m., arbanas, ž. & đomlija, p. (2010): complex landslide in the rječina river valley: monitoring results.– in: horvat, m. (ed.): 4th croatian geological congress, šibenik 14.–15.2010. abstract book, croatian geological survey, zagreb, 157–158. blašković, i. (1999): tectonics of part of the vinodol valley within the model of the continental crust subduction.– geol. croat. 52/2, 153–189. borgatti, l., corsini, a., barbieri, m., sartini, g., truffelli, g., caputo, g. & puglisi, c. (2006): large reactivated landslides in weak rock masses: a case study from the northern apennines (italy).– landslides, 3, 115–124. doi: 10.1007/s10346005-0033-9. casagli, n., catani, f., del ventisette, c. & luzi, g. (2010): monitoring, prediction, and early warning using ground-based radar interferometry.– landslides, 7, 291–301. doi: 10.1007/s10346010-0215-y. cruden, d.m. & varnes, d.j. (1996): landslide type and processes.– in: turner, a.k. & schuster, r.l. (eds): landslides: investigation and mitigation. national academy press, washington, d.c. special report, 247, 36–75. crozier, m.j. (1984): field assessment of slope instability.– in: brunsen, d. & prior, db. (eds.): slope instability. john wiley & sons, new york, 103–142. herak, m., herak, d. & markušić, s. (1996): revision of the earthquake catalogue and seismicity of croatia, 1902–1992.– terra nova, 8, 86–94. hong, y., hiura, h., shino, k., sassa, k. & fukuoka, h. (2005): quantitative assessment on the infl uence of heavy rainfall on the crystalline schist landslide by monitoring system-case study on zentoku landslide, japan.– landslides, 2, 31–41. doi: 10.1007/ s10346-005-0044-6. iaeg (1990): suggested nomenclature for landslides.– bulletin iaeg, 41, 13–16. karleuša, b., oštrić, m. & rubinić, j. (2003): water management elements in regional planning in karst, rječina catchment area – case study.– in: proceedings: water in karst area of watersheds cetina, neretva and trebišnjica, university of mostar, mostar, 85– 94 (in croatian). korbar, t. (2009): orogenic evolution of the external dinarides in the ne adriatic region: a model constrained by tectonostratigraphy of upper cretaceous to paleogene carbonates.– earth-science reviews, 96, 296–312. doi: 10.1016/j.earscirew.2009.07.004. magaš, o. & palinić, n. (1999): rječina and zvir: regulation and revitalization, state archive in rijeka, 76 p., (in croatian). mihalić, s., arbanas, ž., krkač, m., dugonjić, s. & ferić, p. (2010): landslide hazard maps and early warning systems aimed at landslide risk mitigation, proceedings of croatian platform for risk and catastrophe reduction, zagreb, 18–22, (in croatian). moser, m. (2002): geotechnical aspects of landslides in the alps.– in: ribar, j. stemberk, j. & wagner, p. (eds.): landslides, proceedings of the 1st european conference on landslides, 24–26 june 2002, prague. a.a. balkema publishers, 23–43. benac et al.: a complex landslide in the rječina valley: results of monitoring from 1998–2010 geologia croatica 249 rubinić, j., rukavina, j., milković, j., pilko, j., zeko, j. & lukarić, s. (2010): heavy precipitation occurrence in rijeka – problems, measurements and analysis over time.– proceedings of 2nd regional rainfall conference of the balkans: regional rainfall and climate change, belgrade, (in press). skempoton, a.w. & hutchinson, j.n. (1969): stability of natural slopes and embankment foundations, state of the art report: 7th international conference on soil mechanics and foundation engineering, mexico city, 291–340. tomljenović, b., herak, m., herak, d., kralj, k. & matoš, b. (2010): new data on seismotectonic activity in croatia.– in: horvat, m. (ed.): 4th croatian geological congress, šibenik 14.–15.10. 2010. abstract book, croatian geological survey, zagreb, 404–405. varnes, d.j. (1978): slope movements, types and processes.– in:. schuster, r.l. & krizek, r.j. (eds.): landslides, analysis and controls, report, 176, 11–33, national academy of science, washington d.c. velić, i. & vlahović, i. (2009): geological map of the republic of croatia 1:300.000, croatian geological survey, zagreb. yin, y., zheng, w., liu, y., zhang, j. & li, x. (2010): integrati on of gps with insar to monitoring of the jiaju landslide in sichu an, china.– landslides, 7, 359–365. doi: 10.1007/s10346-010-0225-9. manuscript received june 01, 2011 revised manuscript accepted september 01, 2011 available online october 26, 2011 ab stra ct one of the current objectives of karst research is to understand the spatial dynamics of karstic processes that increase or decrease pore volume. although we can construct 3d numerical models, it is a complex, multi-step process. these modelling approaches combine a dissolution algorithm, a flow and/or transport model and an algorithm to reconstruct the spatial geometry of fracture networks. the paper focuses on the last task, and does not consider the first two problems. we applied the repsim code, a dfn (discrete fracture network) type fracture geometry modelling software that uses fractal behavior of fracture patterns, for simulations. this method simulates fracture systems at a reservoir scale. the input parameters (length distribution, aperture, orientation and fractal dimension of the fracture midpoints) were determined using field measurements and evaluation of digitized images. the primary images were of outcrops from the surface and from two caves. the examined area is the karstic block of the mecsek mountains in sw hungary, which is one of the most explored karstic regions in that country. there are seven small and one relatively large (vízfő) catchment areas in the mountains. the large catchment was used as the study area, which lithologically consists of sandstones and limestones, both intensely fractured by subsequent tectonic events. the spatial distribution of cave entrances and dolinas is uneven across the study area. this phenomenon has not yet been investigated. here, a relationship is inferred between the original (prekarstic) microfracture network geometry and the spatial distribution of the aforementioned karst forms. the results show that the region can be divided into two zones that fractured in distinctly different ways. their fracture network communication features, porosity and permeability differ. additionally, sub-regions could develop inside the catchment area where dissolution-cementation processes could have been differently effective, determining the spatial distribution of the dissolution governed karstic forms (e.g. caves, dolinas). keywords: fracture geometry, 3d modelling, vízfő spring, western mecsek mts., hungary  geologia croatica 68/1 11–23 9 figs. 4 tabs. zagreb 2015 geologia croaticageologia croatica modelling microfracture geometry to assess the function of a karst system (vízfő spring catchment area, western mecsek mountains, hungary)  márton bauer and tivadar m. tóth department of mineralogy, geochemistry and petrology, university of szeged h-6723 szeged, egyetem utca 2-4. hungary; (baumart87@gmail.com, mtoth@geo.u-szeged.hu) doi: 10.4154/gc.2015.02 1. introduction karsts are geologically significant for a number of reasons. caves have provided shelter, and karstic springs have offered good quality drinking water since the beginnings of mankind. approximately 25% of the people on earth use karst water daily or live in or near a karstic region (romanov et al., 2004). in addition to the hydrogeological and environmental aspects, karsts are also significant for hydrocarbon exploration. as conventional hydrocarbon deposits diminish geologia croatica 68/1geologia croatica 12 with the growing energy demand, the hydrocarbon industry is paying more attention to the exploration of fractured karstic reservoirs (lun et al., 2010; feng et al., 2013). karstic evolution is a complex process, and the development of these areas is influenced by many factors in both space and time, which may result in an extremely heterogeneous structure and morphology. the quantity and quality of precipitation, the ever-changing surface and the subsurface geomorphology and biological processes are equally important factors. lithological and structural parameters are important as they are more constant in space and time those biological or environmental factors. in numerous limestone bodies where the syngenetic primary porosity has drastically decreased during diagenesis, the main flow paths are fractured structures that developed through different deformation events. they are linked to other “inception” horizons, whose size, form and permeability can greatly change during karst formation. according to palmer (1991), 57% of karstic conduits are related to bedding planes, 42% to fractures and 1% to the rock matrix. one of the main objectives of karst research is to understand the spatial dynamics of karstic processes that increase or decrease pore volume. in the early 1990s, karst system modelling was mainly used to reconstruct individual fracture developments (e.g., palmer, 1991; dreybrodt & gabrovšek, 2000b; bauer et al., 2000). from the mid-1990s, technology enabled 2d models to also be used (kauf mann & braun, 1999, 2000; bauer et al., 2002, 2003; kaufmann, 2003a,b; dreybrodt et al., 2005). we can now construct 3d numeric models, even though this is a complex, multi-step process. three-dimensional numerical models are typically based on three key aspects: a dissolution algorithm, a flow and/or transport model, and an algorithm to reconstruct the spatial geometry of fracture networks. our paper focuses on the last task. the aforementioned studies, depending on their purpose, were interested in reconstructing initial fracture geometry (e.g., jacquet et al., 2004, kaufman et al., 2010; borghi et al., 2012; pardo-iqúzuiza et al., 2012). several papers discuss some regular structure or formula to which the spatial net is applied. the development of computer technology has made it possible to realistically reconstruct more complex geometries, such as karstic networks. the fundamental precondition of a near-reality reconstruction is that the input parameters of the model should be based on measurable factors from the known area. karstic objects are fractal-like objects (e.g., length distribution of caves, (curl, 1986)), so their geometric parameters given in a particular size range can be scaled to both smaller and larger size ranges. it is also notable that, because the quantity and quality of the perceptible factors are variable within a given range, very small and very large forms may not necessarily fit spatial reconstructions. it is best to sample the range of cores, hand specimens and cave passages, and the latter was where pardo-iqúzuiza et al. (2012) began. because more geometric information can be obtained by analyzing microfracture networks in less developed or speleologically less explored karsts (e.g., karstic hydrocarbon reservoirs), we surveyed the parameterizability of these fractures. individual fractures that co-occur, such as karstic forms, can appear in a wide range of scales from submicroscopic to hundreds of metres in diameter (allègre et al., 1982; ouillon et al., 1996; turcotte, 1997) and their features can be compared across different ranges. the structural data of the fractures and microfractures obtained in surface explorations, caves and boreholes can provide important information about large-scale structures, faults and fault-zones. the qualitative features and the values of the measurable parameters (size, spatial density) depend on the petrographic features of the given deformed rock type, e.g., its mineral composition, grain size distribution, structure and former orientation. the physical circumstances in which the deformation takes place also play a vital role; the primary significance of the stress field is substantially modified by the lithostatic pressure, temperature and the rock’s fluid content. the resulting fracture system, as a geometric object consisting of individual fractures, is created as the cumulative result of all these forces. although under the coulomb criterion it is possible to prove the genetic connection between the stress field and the geometry of the fracture system, the former still cannot be deduced from the latter (campos et al., 2005). therefore, the simulation algorithm (dealt with geometry), unlike several others (e.g., olsen, 1993; renshaw & pollard, 1994; riley, 2004), does not examine the evolutionary process of the fracture network in the given stress field, but aims to reconstruct the complex geometry. the karstic block of the mecsek mountains in sw hungary has been investigated for several decades. the purpose of our paper is to supplement the experimental (dye tracing, well data, speleological observations, etc.) modelling results of the fracture system to help understand how the main karst system of the mountains (vízfő) functions. 2. geological background the most important rock types for karstification in the western mecsek mountains are the diverse triassic formations, particularly the anisian lapis limestone. the oldest triassic formation in the area is the jakabhegy sandstone formation (barabás & barabásné, 2005), which is composed of variations of quartz-cemented, cross laminated polymicritic sandstones and conglomerates, followed by the hetvehely dolomite formation, with a total thickness of not more than approximately 40 metres (haas et. al., 2002) . next is the lapis limestone, a highly fractured rock, with relatively high clay and organic content; this formation is thinly layered, sometimes bedded and formed in an innerramp facies. because of the syn-sedimentary deformation events (syn-sedimentary faults) and post-sedimentary faults, the original stratification is highly disturbed and can only be traced in blocks of some tens of metres. because of alpine orogenic movements during the cretaceous, the whole sequence is strongly folded (benkovits et al., 1997; csontos et al., 2002). the study area is located on the northern limb of the main fold (fig. 1). the mecsek mts. were raised and thrust on the northern foreground and partially folded the young sediments (sebe et al., 2008). bauer and tóth: modelling microfracture geometry to assess the function of a karst system (vízfő spring catchment area ... geologia croatica 13 athough the present structure of the mountains was determined by these mesozoic movements, the karstic processes were more strongly influenced by younger tectonic events. the ne–sw structural lines, where fissure caves and karstic cavities formed, opened in the pleistocene in several stages (szabó, 1955). after this tectonic event, n–s and nw–se structural lines formed. in the early holocene, a general rise in the region occurred, which resulted in a significant increase in erosion (szabó, 1955). simultaneously, the karstic water level began to heavily fluctuate, which influenced the valley structure of the western mecsek mts. and strongly affected the formation of its caves (szabó, 1955; lovász, 1971; sebe et al., 2008). the present direction of the largest main stress is ne–sw, which opens parallel fractures and closes perpendicular ones (bada et al., 2007) and has a strong effect on the relationship of the fracture system. the karst-forming layers now typically dip 20° to the north and are heavily folded. no thorough survey has been prepared on the hydrogeological impacts of the structural elements. the neotectonic and geomorphological evolution resulted in eight catchment areas in the central karstic region in the western mecsek mts. (rónaki, 1970) (fig. 1), the largest of which is the catchment area of the vízfő spring. approximately 30% of the 16 km2 catchment area consists of non-karstic formations; the jakabhegy sandstone is the highest relief in the south, while the lapis limestone dominates in the north. our research area covers approximately 60% of the whole catchment, covering the territory between the szuadó-valley, the körtvélyesi-valley and the vízfő cave (fig. 2). data from the most important caves are summarized in table 1. according to szabó (1955), the karst phenomena in this catchment area formed in several individual stages and the valley formation and the subsurface karsts started to develop simultaneously. there are 73 discovered cave entrances in the 16 km2 drainage area. after several decades of speleological research, it is now clear that most of the caves and cave parts (passages, halls) are oriented to the northeast (fig. 3), and numerous caves have siphon endpoints. the figure 1: location of the study area and the karst aquifers of the western mecsek mts. (modified after rónaki, 1971). table 1: topographical data of the main caves in the study area. name length depth distance from vízfő spring entrance asl end point asl   [m] [m] [m] [m] [m] vízfő cave 330 –1 0 211 329 trió cave 255 –55 2550 297 242 gilisztás cave 133 –51 2650 301 250 szuadó cave 345 –52 2800 303 251 geologia croatica 68/1geologia croatica 14 spatial distribution of these caves, however, is uneven, similar to that of dolines. lipmann et al. (2008) found that dolines are concentrated in the central part of the area, defining ne–sw oriented chains for structural reasons. the shapes of individual dolines was not determined by structural effects, but rather by micromorphological and microclimatic circumstances. the average annual precipitation is approximately 600–650 mm, (higher than the hungarian average), which is the result of the strong mediterranean effect. the least precipitation occurs in january, and the most occurs in june, although there is a second peak in the autumn. there are two permanent surface water courses in the area: the orfű-creek in the szuadó-valley and the körtvélyes-creek in the körtvélyesi-valley. their average rate of flow is 52 m3/day and 17 m3/day, respectively. the water from both creeks is directed to the vízfő spring through sinkholes, but our experience shows that a large amount of water leaks underground through the fracture network from the creek beds. little information has been found on the path of the water through the sinkholes. the test results are shown in table 2. the average flow rate of the vízfő spring is 420 m3/day, but can exceed 100,000 m3/day during a flood. figure 2: a simplified geological map of the investigated area (modified konrád et al., 1983). table 2: results of the tracing works in the szuadó-valley. sinkhole date of tracing precipitation difference straigth distance to vízfő spring injected fluoressceine inflow rate average outflow rate first arrival transit time flow velocity     [mm] [m] [g] [l/m] [l/m] [hour] [hour] [m/day] szuadó-barlang 1960. aug. n.d 2800 700 350 2250 210 120 320 gilisztás-barlang 1996. march -13 2650 n.d 3500 n.d 24 12 2650 trió-barlang 1998. april -41 2550 100 250 4100 90 12 680 gilisztás-barlang 2000. jan. 46 2650 200 500 3600 65.6 28.5 970 szuadó-barlang 2001. jan. 46 2800 200 350 3600 82.5 31 815 gilisztás-barlang 2000. march -40 2650 n.d 700 3600 32.3 18.5 1969 asl: above baltic sea precipitation: difference of the previous three mounth precipitatin sum and the long term average precipitation az the same three mounth (1973–2013) n.d: no data available bauer and tóth: modelling microfracture geometry to assess the function of a karst system (vízfő spring catchment area ... geologia croatica 15 3. methods individual fractures can be interpreted as 2d surfaces of finite extension, usually bent in multiple and very complex ways, but can mostly be approached as planar (chiles & de marsily, 1993). in our case, we followed the circle representation in both the parameterization of fractures and further simulation. the geometric parameters clearly describe individual fractures as the spatial position of the circle’s center, the radius and orientation (dip, strike). for a fracture system, this can be interpreted as a function of the spatial density of the center points and a distribution function typical of the radius and dip-strike value-pairs. the hydraulic description of the fracture system needs the positive volume of the individual fractures; therefore, circle plates without thickness were replaced by flat disks with apertures (parallel plate model, witherspoon et al., 1980). discrete fracture network modelling requires characterizing the geometry of individual microfractures, which was completed using the methods described below. abbreviations used to describe the fracture network geometry are summarized in table 3. figure 3: orientation of the largest cave passages in the study area (n=55). table 3: abbreviation of the individual fractures and fracture network parameters. abbreviation meaning l length of a fracture in 2d a aperture of a fracture α dip of a fracture β strike of a fracture n number of fractures d fractal dimension in general e, f – n(l) = f*l-e parameters of the length distribution function a, b – a = a*l+b parameters of the aperture function k number of cases on the histogram 3.1. field work we first localized all outcrops on the surface and subsurface, recording their gps coordinates. the orientation (α, β) of each individual fracture was measured using a compass after the outcrops had been cleaned. next, 5 mp photos were collected from representative sections of the outcrops. in 9 cases, hand specimens were also collected to investigate their microfracture systems under laboratory conditions. using the photos, thousands of individual fractures were digitized from hand specimens using arcview software. digitized images were used to detect the length, distribution, aperture and the relative position of the fractures 3.2. data processing based on previous studies, the distribution of fracture lengths (measured on 2d surfaces) follows a power law distribution, which can be approximated by a straight line on a log(n(l)) – log(l) plot (e.g., yielding et al., 1992; nieto-samaniego et al., 2005). calculating the frequency distribution is the first step for the precise definition of the power law functions. because the number of cases on the histogram can have a great influence on its shape, this number was defined as k = 2 * int(log2(max(l)) (1) neither the shortest nor the longest fracture sets fit on the expected line. both biases come from representative problems at extreme sizes, so they were left out of the subsequent analysis. outlier data were selected using the grubbs test. measuring the fracture aperture is an uncertain task. although there are accurate and accepted methods in the literature (e.g., microct, mri), these techniques require special laboratory equipment. applying these approaches is impossible in the field. in many cases, the distance between the opposite fracture walls could not be measured correctly because of the irregular and rough walls. the aperture of the individual fractures was measured at least three times at three different points (typically four or five). to evaluate the data, the average values of the measured data were used. although there were many uncertainties, previous investigations suggest that the aperture follows a power law distribution similar to the length (de dreuzy et al., 2002; ortega et al., 2006). in addition, a linear correlation exists between the length and the aperture of the individual fractures (barton & larsen, 1985; vermilye & scholz, 1995; gudmundsson, 2000; gudmundsson et al., 2001). the aperture of a single fracture can be described by the following equation: a = a * l + b (2) the two parameters (a, b) can be determined by computing the linear regression between the measured length and the aperture data. the spatial distribution of fractures was analyzed using the fractal dimension of the midpoints of the digitized fractures. there are numerous methods to calculate the fractal digeologia croatica 68/1geologia croatica 16 figure 4: processing methods of a typical sample. a, b) result of the box-counting analysis of fracture midpoints. c, d) frequency distribution of the fracture length values and the corresponding linear regression function. e, f) relationship between the aperture and length values, and the same relationship without the extremely dissolved fractures (applied software: spss 20). 3.3. mapping fracture parameter maps were generated to spatially extend the data measured in discrete points to the whole study area. all maps were computed using surfer 8.0 using the linear kriging approach because there were not enough points to thoroughly fill variography calculations. the grid cells were 40x40 m. 3.4. modelling the repsim code was used many times for 3d fracture network simulations (m. tóth, t. et al., 2004, vass, i. et al., 2009). repsim code has been applied for building the dfn (discrete fracture network) model because it follows the mension, such as mass radius, cumulative intersections, vectorized intersections, convex hull intersections, convex hull, etc. we applied the box counting algorithm (mandelbrot, 1983; mandelbrot, 1985) to characterize the fracture network following the suggestions of barton & larsen (1985) and barton (1995). the benoit 1.0 software was used, which demands 1 bit (black and white) images of the fracture midpoints. two breakpoints typically appear on each point set generated using the box counting algorithm. points below the first one belong to very small box sizes, while those above the second one come from the largest boxes. the two point classes have no geological meaning and are only derived from the applied approach. a regression line was fit between the two breakpoints in each case. bauer and tóth: modelling microfracture geometry to assess the function of a karst system (vízfő spring catchment area ... geologia croatica 17 box-counting algorithm to locate fracture centres and uses the measured d, e and orientation data for simulation. this is a dfn modelling software that uses the fractal geometry behaviour of fracture patterns and is based on the previously mentioned parameters. although many papers suggest that the assumption of circular shaped fractures is more likely to validate in massive rocks, there is absolutely no data to use a polygonal or ellipse approach for the individual fractures. although the simulated system consists of a myriad of discrete flat cylinders, hydrodynamic parameters (porosity, intrinsic permeability tensor) are calculated for a given grid net for hydrodynamic modelling. the size of the grids is defined following the rev (representative elementary volume) concept of bear (1972); the volume, above what the calculated porosity does not change remarkably. following the approach of m. tóth & vass (2011), rev is defined at the grid size where the variation coefficient of porosity becomes stable. it is important to note that porosity, permeability and rev calculations relate only the fracture system and the model ignores the effect of the bedding planes. 4. data measured fracture length data follow the expected power law distribution in each studied locality, so the e and f parameters needed for modelling were derived. similarly, a box counting calculation was successful in each case, and the d parameter, representing the spatial distribution of fracture midpoints, was computed in all 11 study points. the results from the parameter calculations are in table 4, and the evaluated data of a typical sample are in figure 4. the results from the aperture measurements show some deviation from the assumed linear relationship, likely because of dissolution for a few microfractures. most fractures lie along the trend line (figs. 4e,f) if the strongly dissolved fractures were ignored during the linear regression calculations (c.f. equation 2). parameter maps calculated using normal krigings are illustrated in figure 5. 5. discussion 5.1. simulated fracture network at the beginning of modelling, we defined the primary cell edge as 10 m, which was halved during the iteration process until we reached a minimal cell length of 1 m. this method required four iteration steps, during which we generated approximately 113000 single fractures. for each midpoint, a sinfigure 5: spatial distributions of the measured parameters. a) map of the d parameter. b) map of the e parameter. c) map of the aperture. white circle = sampling locations; black circle = cave entrances. a) b) c) table 4: measured geometrical parameters of the fracture network. sample n d e f a b sárkányvölgy_1 198 1.45 –1.94 10.78 0.004 0.934 körtvélyesi_1 40 1.28 –1.28 5.71 0.002 0.436 körtvélyesi_2 109 1.84 –0.67 4.23 0.22 0.486 vízfő cave 59 1.35 –0.41 2.89 0.10 0.701 trió cave 861 1.69 –2.03 13.35 0.008 1.53 szuadó valley_1 107 1.84 –0.94 6.10 0.004 0.829 szuadó valley_2 85 1.37 –0.76 4.15 0.014 0.438 szuadó valley_3 40 1.33 –0.49 3.51 0.007 0.071 szaudó valley_4 87 1.35 –1.42 6.99 0.035 0.112 nagykaszáló_1 88 1.54 –1.82 3.65 0.032 0.034 nagykaszáló_3 53 1.45 –1.13 5.22 0.091 0.265 n = number of the digitalized fractures geologia croatica 68/1geologia croatica 18 gle fracture was chosen from the 1–50 m length interval using the calculated length distribution. altogether, 10 independent fracture network models were computed and evaluated. in each case, the generated model forecasted two fields of dramatically different behaviours: a highly fractured zone, which has at least one well-commutating fracture group (type 1) and a zone, which has no well-communicating fracture cluster at all (type 2) (fig. 6). the connectivity of a fracture group can be defined by the proportion of the interconnected fractures. it essentially depends on the d, e and orientation values of the fracture network (m. tóth & vass, 2011). in this paper a fracture group was considered well-communicating if it contains more than 5% of all simulated fractures from the modelled volume. two large, independent fracture groups were rendered probable in the area. one on the southeastern part contained approximately 10% of all of the fractures (type 1a), while another communicating system in the north contained approximately 5% (type 1b). both zones had relatively low d values (~1.26) and relatively low e values (<1.00), suggesting that the fractures were relatively long. in the type 2 zone, geographically surrounded by type 1a and type 1b areas, even the largest fracture networks consist of no more than approximately 0.1% of all fractures. this region is characterized by high d values (~1.6) and high e values, which suggests that, even if a dense fracture system was typical here because the network is dominated by short fractures, the number of communicating subsystems is subordinate (fig. 7). to test how well-connected the type 1 systems are, each fracture with a length below a certain threshold was diminished to model the possible role of vein cementation. as the simulation of cementation goes on, the size of the communicating clusters decreases evenly. even if fractures with apertures of 120 mm (l = 20 m) are closed, a remarkably large communicating fracture group can be rendered probable, suggesting a mature 3d fracture system is present both in the northern and southern part of the study area. the variation coefficient calculated from the average and standard deviation data of porosity for different grid sizes stabilizes at approximately 0.6, so we defined the rev typical of type 1 zones in the corresponding 50 m. the fractured porosity for fractures of at least 1 m (aperture 8 mm) for this rev is 6.8%, which is considered good porosity for triassic reservoirs. if we also include other possible porosity types (solution, along bedding, etc. (choquette & pray, 1970), however, this area seems to have outstanding porosity. the permeability tensor calculated for the representative volume shows significant ne-sw anisotropy of 1.37 with an average value of 8*10-11 m2. this direction does not depend on the orientation of the particular fractures but is closely connected to the anisotropy of the fracture density (fig. 6). in type 2 zones, the biggest connected fracture group in the models only generates 0.01% of the fractures, while plenty of small fracture groups are evenly distributed. rev is defined as 70 m for this area. the fractured porosity calculated for a volume above rev is < 0.001%, which means that this zone has neither storage nor conducting capacities. that is why we believe that the slight ne–sw permeability anisotropy typical of this area has no practical geological effect. the calculated average fractured permeability of 6*10-13 m2 must be even smaller because the fractures do not define a connected network. according to the previous statements, one can see that the fracture system of the examined area and its hydrodynamic features (porosity, permeability) are not uniform. the northern and southern parts of the area have outstanding effective fracture porosity, while in the middle, it is practically negligible. considering the hydrodynamics and karst formation of the area however, it is extremely important to know the joint features of the three different zones. the rev calculated for the whole area is approximately 90 m, which is rather high compared to other case studies (e.g., wu & kulatilake, 2012). this increase in size is because linking the two types of areas results in a substantial growth in the standard deviation of porosity. the fractured porosity above this rev is 2%, which is an average effective porosity value for the figure 6: calculated communicating fracture groups, and the horizontal segments of the permeability anisotropy ellipsoids in the three differently fractured domains. figure 7: typical horizontal sections of the different types of the simulated fracture networks (not to scale). bauer and tóth: modelling microfracture geometry to assess the function of a karst system (vízfő spring catchment area ... geologia croatica 19 whole of the studied karstic reservoir. using other methods, vass (2012) obtained similar results for the catchment of the nearby tettye spring, where the lithological and structural environment is the same. 5.2. geological and morphological consequences although the dominating lapis limestone has different varieties, there is no evidence for different dissolution abilities. additionally, current and palaeo-climatic parameters do not differ either; there are no places with local maximum and minimum values of precipitation. there are no substantial differences in the elevation of the study area, so we can assume that the main factors influencing epigenic karstic formation (soluble rock, precipitation of appropriate quality and quantity) affected the whole area to the same degree. there can be a crucial difference in the state of deformation of the rocks, which can affect the present surface and subsurface morphology as well. the modelling results suggest that the spatial distribution of the rate of brittle deformation is extremely heterogeneous in the area. the ne–sw orientation manifested in fracture density maps is also shown by structural geological surveys performed on a larger scale in the wider area of the mecsek mts. (csontos et al., 2002; lipmann et al., 2008; konrád & sebe, 2010). this renders the genetic link of microand macro-structures probable, so our observations are coherent with the statement that fracture patterns follow a scale-invariant pattern and can be modelled by fractal geometric approaches (yielding, 1992; korvin, 1992; nieto-samaniego et al., 2005; m. tóth, 2010). although this research did not target the analysis of the fracture-system genetics, the spatial distribution of the different fracture systems is still closely related to well-known tectonic events. we found that when the short fractures in the model were blocked (e.g., mimicking cementation), the size of the fracture system in the southern part of the area (system type 1a) decreased from south to north. our measurements showed that the basic difference between the northern and southern regions of the study area, compared to the central region, was the length distribution of the fractures. one reason for such a crucial spatial variability of fracture lengths may be the complex tectonic evolution of the region. the deformation response to the given stress field systematically changed when moving away from the anticline axis of the western mecsek mts. (fig. 1). relatively few, but larger fractures formed near the axis, while a denser fracture system of smaller fractures formed (type 1a) further away. the fracture system in the south seems to be fold related, but the northern region is related to the fault system that created the orfű basin (type 1b) (fig. 8). gabrovsek et al. (2004) and singurindy & berkovitz (2005) observed that the net efficiency of karstic processes is significantly higher in well-fractured zones where the permeability and flow velocity are much higher inside a given rock mass. in these regional processes doline formation, karren formation, or even cave formation may be enhanced. in the less fractured zones, fractures are cemented and karsts typically do not form. in intensely fractured zones, a positive feedback process occurs. during this process, the more opened fractures have larger soluble surfaces, which enhance solution processes, so the karst formation process speeds up (jakucs, 1971; m. tóth, 2003; filipponi et al., 2009). structural control like this is wellknown in several karstic areas (billi et al., 2007). the results suggest that the relationship between different karstic forms and the fracture systems should be independently studied for the three diverse fracture patterns. figure 8: cross-section along the a–a' line (see fig. 2) with the conceptual fracture systems. geologia croatica 68/1geologia croatica 20 type 1 these areas can be characterized by a communicating fracture system with high permeability and porosity values. we can expect significant solution forms in this type of area. there is no difference in the karstic phenomena between type 1a and type 1b and all known large caves are all type 1. these caves (e.g., trió cave, szuadó cave, gilisztás cave, vízfő cave, fig. 2) formed through solution along fractures and erosion. tectonic preformation substantially influenced and is influencing cave formation today. although the regional flow gradient follows to the north because of the position of the anticline, all of the aforementioned caves are oriented ne–sw, corresponding to the orientation of the permeability anisotropy previously calculated. dolines are relatively rare in these two zones (lipmann et al., 2008). type 2 singurindy & berkovitz (2005) discuss that in areas of low porosity and permeability, cementation processes dominate. in the central zone of the study area, this statement is supported by the lack of significant (longer than 50 m) caves. the orientations of all known small cave-entrances and immature vertical caves do not follow the permeability anisotropy. the very low rate of underground karstic processes is because the zone has little fractured porosity and no ability to conduct water. in this zone, the number of dolines is remarkably high (lipmann et al., 2008), but ne–sw orientations are atypical. as these dolines are neo-formations (lipmann et al., 2008), we think that the geometrical features of micro-fractures must have determined the initial stage of doline and doline-chain formation according to singurindy & berkovitz (2005). the relatively high number of individual fractures (d=~1.6) can be the main reason for the high doline number. although the there are many dolines in this area, these are very immature probably as a result of the low permeability of the fracture system, which is coherent with the conclusion of singurindy & berkovitz (2005). additionally, a significant number of the small caves in the area are linked to dolines from a solution origin. czigány and lovász (2006) emphasized the definite ne–sw orientation of the doline chains without any orientation of the particular dolines. this agrees with the orientation of the large structural elements throughout the study area, while the microfracture networks are immature. 5.3. theoretical model the two large fracture groups (type 1) found in the southwestern and northern part of the study area can be identified with the spatial location of the most important caves. the model predicts the largest interconnected fracture system near the szuadó valley caves, while the second largest interconneccted zone is predicted to be near the vízfő cave (fig. 9). in the case of the szuadó valley sinks, the fracture model assumes a connected fracture system exists, which suggests that the szuadó, gilisztás and trió caves are directly connected. this does not necessarily mean the connection can be passed through by people. radon gas exploration was used for the szuadó valley sinks (koltai et al., 2010) to explore the connection. the series of measurements was not successful, as it could not prove or exclude connections. this issue still requires more research as earlier explorations did not target the relationship of caves to each other. figure 9: effect of the fractures and bedding on the hydraulic behaviour of study area. the main conductive zones are fault related fractures (yellow), and according to the dfn m del, there is an unfractured, bedding only, hydrological connection between the inflow and outflow regions. bauer and tóth: modelling microfracture geometry to assess the function of a karst system (vízfő spring catchment area ... geologia croatica 21 there is a hydrological connection between the sinks and the spring areas (gila, 2000), although no passages have been found between the two highly fractured regions. only a certain amount of water leaking into the karst moves along the fracture planes. without these planes, a large volu me of water may move along bedding planes (kaufmann, 2003; kaufmann & romanov, 2008). a typical example is the initial section controlled by planes in the szuadó valley sink caves (e.g., trió cave), which can carry as much as several hundreds of litres of water per minute (unpublished). in these caves, these sections are typically oriented north south, so the strongly northerly average plane inclination on the northern wing of the anticline contributes to the northeast run of the caves. we observed that, after a short initial section of the sinks, the flow tracks connect to mature fractures. the flow rate does not grow along the planes during floods, but even small fractures have significant flow rates. although the karst and spelaeology literature provides information on a large number of caves with important galleries following the bedding planes, the cave evolution in the mecsek mts. depends mostly on the fracture network and fault system. the bedding is disrupted by synand post-sedimentary faults, fractures and folds, so the lateral spreading is smaller than a few tens of metres. although there are no flow-place measurements (in fractures, faults or on bedding planes) of karstic water, passage features in the vízfő spring between the sinks and the spring were examined by dye tracing tests (gila, 2000; szőke & ország, 2006; rónaki, 2007). although these surveys have shown a short time before appearance of the dye and thus a strong hydrological connection, because of the very high deviation of the first arrivals, these passage feature estimations are extremely uncertain (table 1). despite the rapid appearance, each dye tracing test experiment showed some slowing features in the hydrological system. gila (2000) and szőke and ország (2006) assumed that slowing by siphons or storage lakes occurs because the transition time is not stable; it can be short or long. the previously discussed model that predicts the coexistence of different fractured zones in the area implies that the slowing factor between the sinks and the springs should not be a series of siphons or storage lakes, but that the poorly connected fracture system is responsible for this phenomenon. the slowing rate of the middle zone must depend on the quantity of the received water. the extremely rainy period in 2010 is a good example of this. in 2010, there was a fluctuation of more than 50 m in the water level of the szuadó valley caves, while in the other part of the karst, around the spring, the water level did not even reach 5 m (unpublished). using the current fracture model, in the type 2 zone, the fracture network is unconnected and the bedding planes alone are responsible for water flow. as soon as they became saturated, further tapping was impossible along bedding planes where there is low permeability. the middle zone then slows and diverts the flow from a northern to a northeastern direction. the fact that the karstic water arriving at the southern border of the non-communicating zone has to turn to the northeast is a very important element in the hydrogeological system and the development of the cave orientations. to sum up, our model suggests that in the catchment of the vízfő cave between the szuadó valley caves and the vízfő spring, a zone should exist where cave maturity is significantly underdeveloped compared to its vicinity because of tectonic preformation. this zone plays an important role in the hydrology of the area as it greatly decreases the permeability between the sinks and the spring, and practically diverts flowing waters to a northeasterly direction. 6. conclusions • through the study and modelling of the microfracture network in the examined area, the vicinity previously considered homogeneous can be divided into three distinctly different zones which differ in fracture network connectivity, porosity, permeability and type of karst development. • in the study area, the rev calculated on fractured porosity is approximately 90 m, but for the well-fractured sub-areas, this volume is much smaller (50 m). • there are direct fracture geometric connections between the sinks of the szuadó valley (szuadó, gilisztás and trió caves), but they are not necessarily passable by people. • we have increased the knowledge of the karstic development in the area with new elements by studying the microfracture network and applying the previously discussed simulation method. this method makes it possible to simulate fractures on a reservoir scale using point-type data (even drills). this can be extremely important for exploration of hydrocarbon and geothermal reservoirs. acknowledgement the authors would like to thank jános ország (mecsekérc plc.) for providing useful hydrogeological information about the investigated area. spelling and grammar was corrected by american journal experts. references allègre, c.j., le mouel, j.l. & provost, a. (1982): scaling rules in rock fracture and possible implications for earthquake prediction.– nature, 297, 47–49. bada, g., horváth, f., dövényi, p., szaffián, p., windhoffer, g. & cloetingh, s. (2007): present-day stress field and tectonic inversion in the pannonian basin.– global and planetary change, 58, 165–180. barabás & barabás-stuhl, á. (2005): geology of the lower triassic jakabhegy sandstone formation, hungary, se transdanubia.– acta geologica hungaica, 48, 1–47. barton, c.c. & larsen, e. (1985): fractal geometry of two-dimensional fracture networks at yucca mountain, southwestern nevada.– fundamentals of rock joints: proceedings of the international symposium on fundamentals of rock joints, 77–84. geologia croatica 68/1geologia croatica 22 barton, c.c. (1995): fractal analysis of scaling and spatial clustering of fractures.– in: barton, c.c. & la pointe, p.r. (eds.): fractals in the earth sciences. plenum press, new york, 168 p. bauer, s.& liedl, r. (2000): modelling of karst development considering conduit-matrix exchange flow. calibration and reliability in groundwater modelling (proceedings of the modelcare 99 conference held at zurich, switzerland, september 1999).– iahs publ. no. 265, 2000. bauer s., liedl, r. & sauter, m. (2002): modelling of karst genesis at the catchment scale influence of spatially variable hydraulic conductivity.– acta geologica polonica, 52, 13–21. bauer, s., liedl, r. & sauter, m. (2003): modelling of karst aquifer genesis-influence of exchange flow.– water resources research, 39 p. benkovits, l., csontos, l., mansy, j.l. & bergerat, f. (1997): folding in the abaliget road cut.– acta geologica hungarica, 40/4, 425–440. billi, a., valle, a., brilli, m., facenna, c. & funiciello, r. (2007): fracture controlled fluid circulation and dissolutional weathering in sinkhole-prone carbonate rocks from central italy.– journal of structural geology, 29, 385–395. borghi, a., renard, p. & jenni, s. (2012): a pseudo-genetic stochastic model to generate karstic networks.– journal of hydrology, 414–415, 516–529. campos, i., balankin, a., bautista, o. & ramírez, g. (2005): self-affine cracks in a brittle porous material.– theoretical and applied fracture mechanics, 44/2, 187–191. chiles, j. & de marsily, g. (1993): stochastic models of fracture systems and their use in flow and transport modelling.– in: bear, j., tsang, c. f. & de marsily, g. (eds.): flow and contaminant transport in fractured rock. academic press, inc, 169–236. choquette, p.w. & pray l.c. (1970): geologic nomenclature and classification of porosity in sedimentary carbonates.– aapg. bulletin, 54, 207–250. curl, r.l. (1986): fractal dimensions and geometries of caves.– mathematical geology, 18/8, 765–783. czigány, sz. & lovász, gy. (2006): a mecseki karszt térképezésének újabb eredményei [new results of the mapping on the karstic area of mecsek mountain – in hungarian].– közlemények a pécsi tudományegyetem földrajzi intézetének természetföldrajzi tanszékéről, 28, 3–14. csontos, l., benkovits, l., bergerat, f., mansy, j.l. & wórum, g. (2002): tertriary deformation history from seismic section study and fault analysis in former european tethyan margin (the mecsek-villány mountains area, sw hungary).– tectonophysics, 357, 81–102. de dreuzy, j. r., davy, p. & bour, o. (2002): hydraulic properties of two-dimensional random fracture networks following power law distributions of length and aperture.– water resources research, 38/12, 121–129. dreybrodt, w. & gabrovsek, f. (2000): dynamics of the evolution of a single karst conduit.– in: klimchouk, a.b., ford, d.c., palmer, a.n. & dreybrodt, w. (eds.): speleogenesis: evolution of karst aquifers, national speleological society, usa: 184–193. dreybrodt, w., gabrovšek, f. & perne, m. (2005): condensation corrosion: a theoretical approach.– acta carsologica, 34/2, 317–348. feng, k., cao, j., hua, k., peng, x., chen, y., wang, y. & wang, m.: (2013): dissolution and its impacts on reservoir formation in moderately to deeply buried strata of mixed siliciclastic and carbonate sediments, northwestern qaidam basin, northwest china.– marine and petroleum geology, 39, 124–137. filipponi, m., jeannin, p. & tacher, l. (2009): evidence of inception horizons in karst conduit networks.– geomorphology, 106, 86–99. gabrovsek, f., romanov, d. & dreybrodt, w. (2004): early karstification in a dual-fracture aquifer: the role of exchange flow between prominent fractures and a dense net of fissures.– journal of hydrology, 299/1–2, 45–66. gila, cs. (2000): barlangjárat-jelleg vizsgálata vízfestéses eljárással a nyugat-mecseki karszton [characterization of the caves in the western mecsek by tracing methods – in hungarian].– unpubl. phd theses, university of szeged department of physical geography and geoinformatics, 1–26. gudmundsson, a. (2000): fracture dimensions, displacements and fluid transport.– journal of structural geology, 22/9, 1221–1231. gudmundsson, a., berg, s.s., lyslo, k.b. & skurtveit, e. (2001): fracture networks and fluid transport in active fault zones.– journal of structural geology, 23/2–3, 343–353. haas, j., budai, t., hips, k., konrád, gy., török, á. (2002): magyarországi triász fáciesterületek szekvencia-rétegtani elemzése. [sequence stratigraphy of triassic facies areas in hungary – in hungarian].– földtani közlöny, 132/1, 17–43. jacquet, o., siegel, p., klubertanz, g. & benabderrhamane, h. (2004): stochastic discrete model of karstic networks.– advances in water resources, 27/7, 751–760. jakucs, l. (1971): a karsztok morfogenetikája (morphogenetic of karst regions – in hungarian).– akadémiai kiadó, budapest, 46 p. kaufmann, g. & braun, j. (1999): karst aquifer evolution in fractured rocks.– water resources research, 35, 3223–3238. kaufmann, g. & braun, j. (2000): karst aquifer evolution in fractured, porous rocks.– water resources research, 36, 1381–1391. kaufmann, g. (2003a): a model comparison of karst aquifer evolution for different matrix-flow formulations.– journal of hydrology, 283/1–4, 281–289. kaufmann, g. (2003b): modelling unsaturated flow in an evolving karst aquifer.– journal of hydrology, 276/1–4, 53–70. kaufmann, g. & romanov, d. (2008): cave development in the swabian alb, south-west germany: a numerical perspective.– journal of hydrology, 349, 302–317. kaufmann, g., romanov, d. & hiller, t. (2010): modelling three-dimensional karst aquifer evolution using different matrix-flow contributions.– journal of hydrology, 388/3–4, 241–250. koltai, g., ország, j. & tegzes, z. (2010): radontransport mesaurments in mecsek mountains.– karst development, 1, 18–30. konrád, gy. & sebe, k. (2010): fiatal tektonikai jelenségek új észlelései a nyugat-mecsekben és környezetében [new details of young tectonic phenomena in the western mecsek mts. and their surroundings – in hungarian].– földtani közlöny, 140/2, 135–163. korvin, g. (1992): fractal models in the earth sciences.– elsevier, 396 p. lipmann, l., kiss, k. & móga, j. (2008): az abaliget-orfűi karszt karsztos felszínformáinak vizsgálata térinformatikai módszerekkel [investigation of the karstic phenomenon near orfű and abaliget by gis methods – in hungarian].– karsztfejlődés, 13, 151–166. lovász, gy. (1971): adatok az abaligetikarszt geomorfológiai és hidrológiai jellemzéséhez [data for the characterization of the hydrology and geomorphology of the abaliget karst – in hungarian].– földrajzi értesítő, 47/3, 283–296. lun, z., jianxin, l., kongchou, l., zifei, f., heng, s. & xubin, c. (2010): development and genetic mechanism of complex carbonate reservoir fractures: a case from the zanarol oilfield, kazakhstan.– petroleum exploration and development, 37/3, 304–309. mandelbrot, b.b. (1983): the fractal geometry of nature.– freeman, new york, 468 p. bauer and tóth: modelling microfracture geometry to assess the function of a karst system (vízfő spring catchment area ... geologia croatica 23 mandelbrot, b.b. (1985): self-affine fractal dimension.– physica scripta, 32, 257–260. tóth, t.m. (2003): mészkő területek repedésrendszerének modellezési lehetőségei [modelling possibilities of limestone areas – in hungarian].– in: ünnepi tanulmányok keveiné bárány ilona professzor asszony tiszteletére, szeged, 447–455. tóth, t.m., hollós, cs., szűcs, é. & schubert, f. (2004): conceptual fracture network model of the crystalline basement of the szeghalom dome (pannonian basin, se hungary).– acta geologica hungarica, 47/1, 19–34. tóth, t. m. (2010): determination of geometric parametres of fracture networks using 1d data.– journal of structural geology, 32/7, 878–885. tóth, t. m. & vass, i. (2011): relationship between the geometric parametres of rock fractures, the size of percolation clusters and rev.– mathematical geosciences, 43/1, 75–97. nieto-samaniego, a.f., alaniz-alvarez, s.a., tolson, g., olescho k., korvin, g., xu, s.s. & perez-venzor j.a. (2005): spatial distribution, scaling and self similar behavior of fracture arrays in the los planes fault baja, california sur, mexico.– pure and applied geophysics, 162, 805–826. olsen, j.e. (1993): joint pattern development: effects of subcritical crack growth and mechanical crack interaction.– journal of geophysical research, 98, 12251–12265. ortega, o. j., marrett, r. a. & laubach, s. e. (2006): a scaleindependent approach to fracture intensity and average spacing measurement.– aapg bulletin, 90/2, 193–208. ouillon, g., castaing, c. & sornette, d. (1996): hierarchical geometry of faulting.– journal of geophysical research, 101, 5477–5487. palmer, a.n. (1991): origin and morphology of limestone caves.– geological society of america bulletin, 103, 1–21. pardo-iqúzuiza e., dowd, p.a., xu, c. & durán-valsero, j.j. (2012): stochastic simulation of karst conduit networks.– advances in water resources, 35, 141–150. renshaw, c.e. & pollard, d.d. (1994): numerical simulation of fracture set formation: a fracture mechanics model consistent with experimental observations.– journal of geophysical research, 99, 9359–9372. riley, m.s. (2004): an algorithm for generating rock fracture patterns mathematical analysis.– mathematical geology, 36/4, 683–702. romanov, d., gabrovsek, f. & dreybrodt, w. (2004): modelling the evolution of karst aquifers and speleogenesis. the step from 1-dimensional to 2-dimensional modelling domains.– speleogenesis and evolution of karst aquifers, 2/1, 2–28. rónaki, l. (1970): vízfő forrás és barlangjának kutatása [researach of the vízfő spring and the cave behind the spring – in hungary].– karszt és barlang, 1, 25–30. rónaki, l. (2007): a mecseki karszton történt víznyomjelzések áttekintése [overview of the water tracing in the mecsek mountain – in hungarian].– karsztfejlődés, 13, 91–103. sebe, k., csillag, g. & konrád, gy. (2008): the role of neotectonics in fluvial landscape development in the western mecsek mountains and related foreland basins (se transdanubia, hungary).– geomorphology, 102, 55–67. singurindy, o. & berkowitz, b. (2005): the role of fractures on coupled dissolution and precipitation patterns in carbonate rocks.– advances in water resources, 28, 507–521. szabó, p. z. (1955): a fiatal kéregmozgások geomorfológiai és népgazdasági jelentősége a déldunántúlon [geomorphological and economic significance of the young structural deformations in sw hungaria – in hungarian].– dunántúli tudományos intézet gyűjteménye iv, 12–26. szőke, e. & ország, j. (2006): a mecseki rumba-barlang víznyomjelzéses vizsgálata [research the rumba cave by tracing methods in the western mecsek mts. – in hungarian].– karst development, 11, 275–286. turcotte, d.l. (1997): fractals and chaos in geology and geophysics.– cambridge university press, 412 p. vass, b. (2012): vízhozam és hézagtérfogat számítás magaskarszt forrásoknál a tettye példáján [well capacity and porosity calculating on the tettye spring catchment area – in hungarian].– in: barta, k. & tarnai, t. (eds.): a nyugatmecsek karsztja. geolitera: 69–75. vass, i., tóth t.m., szanyi, j. & kovács, b. (2009): az aljzati kristályos hátak szerepe az alföld fluidum áramlási és hőtranszport folyamataiban [the role of the crystallic domes of the basement in the fluid migration and thermotransport processes – in hungarian].– in: tóth, t.m. (eds): magmás és metamorf képződmények a tiszai egységben. geolitera, 325–341. vermilye, j.m. & scholz, c.h. (1995): relation between vein length and aperture.–journal of structural geology, 17/3, 423–434. witherspoon, p.a., wang, j.s.y., iwai, k. & gale, j.e. (1980): validity of cubic law for fluid flow in deformable rock fracture.– water resources research, 16/6, 1016–1024. wu, q. & kulatilake, p.h.s.w. (2012): rev and its properties on fracture system and mechanical properties and an orthotropic constitutive model for a jointed rock mass in a dam site in china.– computers and geotechnics, 43, 124–142. yielding, g., walsh, j.j. & watterson, j. (1992): the prediction of small scale faulting in reservoirs.– first break, 10, 449–460. manuscript received june 24, 2014 revised manuscript accepted november 06, 2015 available online february 27, 2015  geochemical implications for the magma origin of granitic rocks from the ditrău alkaline massif (eastern carpathians, romania)  elemér pál-molnár1,2, anikó batki1,2, ágnes ódri1, balázs kiss2 and enikő almási1 1 vulcano research group, department of mineralogy, geochemistry and petrology, university of szeged, egyetem street 2, h-6722 szeged, hungary 2 mta-elte volcanology research group, pázmány péter street 1/c, h-1117 budapest, hungary (corresponding author: batki@geo.u-szeged.hu) doi:10.4154/gc.2015.04 ab stra ct in addition to a series of ultramafic to mafic and alkaline igneous rocks, a granite body also occurs in the ditrău alkaline massif, eastern carpathians, romania. we present and discuss mineral chemical data, and major and trace element compositions of the granites in order to define their nature and origin and to determine the depth of the magma emplacement. the granites consist of k-feldspar, albite to oligoclase and quartz accompanied by ti-rich annite ± calcic amphiboles. depending on the amphibole content they are classified as less fractionated amphibole-bearing and amphibole-free varieties. accessories include zircon, apatite, magnetite, ilmenite, and allanite or monazite. high zr, nb, ga, ce and y content and ga/al and fe/mg ratios, together with low cao, sr and ba contents and y/nb ratios of 0.04-0.88 are consistent with a1-type granites and mantle differentiates correspond to an intra-plate environment. the ditrău alkaline massif granites were emplaced at middle – upper crustal levels between 14 and 4 km depth as indicated by the calculated crystallization pressure of 370 ± 40 mpa and the stability limit of calcic amphiboles. keywords: a-type granite; geochemistry; mantle differentiates; amphibole geobarometry; ditrău alkaline massif, eastern carpathians, romania a wide variety of igneous rocks have been described in the dam from ultramafic to mafic ones (tarniţa complex: peridotites, gabbros, diorites), felsic silica-saturated and oversaturated syenites and granites, as well as undersaturated alkaline rocks (nepheline syenites) (pál-molnár, 2000). the massif is the locus typicus of several magmatic rock types that were first identified here, e.g. ditróite, orotvite and ditróessexite. previously these names were widely accepted in the international petrographical literature, though by now the iugs does not recommend their use. numerous dykes, including lamprophyres, tinguaites and alkali feldspar syenites, cut across the whole complex (batki et al., 2014). geologia croaticageologia croatica geologia croatica 68/1 51–66 9 figs. 4 tabs. zagreb 2015 1. introduction since the nineteenth century many studies have examined the mineralogy, petrology and geochemistry of the ditrău alkaline massif (dam) (e.g. koch, 1879; ianovici, 1938; streckeisen, 1938, 1952, 1954; codarcea et al., 1957; streckeisen & hunziker, 1974; anastasiu & constantinescu, 1982; pál-molnár, 1992, 1994a, 2000; pál-molnár & árva-sós, 1995; dallmeyer et al., 1997; kräutner & bindea, 1998; jakab, 1998; morogan et al., 2000; fall et al., 2007; batki et al., 2014), however, there is still a great debate on the petrogenesis of the dam. geologia croatica 68/1geologia croatica 52 the structural system of the alpine-carpathian-dinaric region it belongs to the dacia mega-unit (median dacides; săndulescu, 1984) (fig. 1.a). the massif intruded the variscan metamorphic rocks of the eastern carpathians, later participating in the alpine tectonic events along with these metamorphic rocks (pál-molnár, 1994b). structurally, the dam is the part of the alpine bucovinian nappe system having direct contact with three of its pre-alpine (variscan) lithogroups: the bretila (rarău nappe), rebra (rodna nappe) and tulgheş lithogroups (putna nappe) (balintoni, 1997, 1981) (fig. 1b). the bucovinian nappe represents the upper unit of the central eastern carpathian nappes which were formed during the middle cretaceous (săndulescu, 1984). the dam is partly covered by neogenequaternary andesitic pyroclastics and lava flows of the călimani–gurghiu–harghita volcanic chain and by pliocene–pleistocene sediments and lignite-bearing lacustrine deposits of the gheorgeni and jolotca basins (codarcea et al., 1957). it is most likely that the intrusion was related to the opening events of the meliata–hallstatt ocean (hoeck et al., 2009), where main rifting began during the pelsonian substage (middle triassic) (kozur, 1991). the north-eastern part of the dam was previously considered to be a homogeneous granite body (jakab, 1998). however, kovács & pál-molnár (2005) and pálmolnár (2006) pointed out that there are various types of felsic granitic rocks in this area. currently, two main hypotheses have emerged concerning the origin of the granite: (1) granites have resulted from the differentiation of mantle-derived melts (morogan et al., 2000; pál-molnár, 2000) or (2) granites have been formed from silica-poor magmas contaminated by the felsic crust (streckeisen & hunziker, 1974; jakab, 1998), without mentioning any particular source of these magmas. in this paper we discuss new geochemical and petrological data on granites and draw conclusions on processes of magma evolution in order to provide further constraints on the formation of the ditrǎu alkaline massif. 2. geological setting the ditrǎu alkaline massif forms the southern and south western part of the giurgeu mountains (eastern carpathians, romania). it is 19 km long and 14 km wide and ca. 200 km2 in size on the surface (pál-molnár, 2000) (fig. 1). in figure 1: (a) location of the dam in the alpine-carpathian-dinaric region (after săndulescu et al., 1981, modified). (b) structural units of the easterncarpathians (pál-molnár, 2010). (c) sample locations in the northern part of the dam (pál-molnár, 2000). pál-molnár et al.: geochemical implications for the magma origin of granitic rocks from the ditrău alkaline massif (eastern carpathians, romania) geologia croatica 53 mineral phases of the studied granites were analyzed with a jeol jcxa-733 electron microprobe in wavelengthdispersive mode using a beam current of 15 na and an acceleration voltage of 20kv at the institute for geological and geochemical research, research centre for astronomy and earth sciences, hungarian academy of sciences, budapest, hungary. 4. petrography and mineral chemistry 4.1. petrography the studied granites are generally light grey with a light reddish tone. the rocks are inequigranular and exhibit a phaneritic texture. the main constituents are quartz (20–37%), kfeldspar (up to 50%), plagioclase (ca. 10–35%) and subordinate biotite ± amphibole (ca. 2–16%) (fig. 2). amphibole is frequently altered and occurs in half of the granite samples. the presence of amphibole in the granite does not depend on the location; amphibole-bearing granite occurs randomly throughout the granite body. chlorite, epidote, magnetite and titanite as alteration products commonly appear after amphibole (fig. 2a). quartz is observed in the rocks as a mediumto coarsegrained anhedral phase (250–1500 µm). plagioclase is usually direct contact of the massif with sedimentary rocks is not observed. the first k/ar ages were published by bagdasarian (1972) who determined a neocomian (125±10 ma) age of the dam granites. afterwards, pál-molnár & árva-soós (1995) using k/ar ages on amphibole and biotite separates, produced an average date of 206±7.8 ma for the granites and suggested a late triassic age for them. the largest granite body crops out in the north-eastern part of the dam, east of the turcului creek and north of the jolotca creek (fig. 1c). 3. samples and analytical methods samples of granites were collected from the right side of jolotca creek (creangă mare, laposbükk, turcului, holoşag and ţengheler mic creeks) (fig. 1c). whole-rock major element compositions were analyzed by icp mass spectrometer (finnigan mat element) and trace elements were determined by icp atomic emission spectrometry using a varian vista ax spectrometer at the department of geological sciences, university of stockholm. additional bulk rock analyses were carried out by icp ms at the acme analythical laboratory, vancouver, canada. figure 2: characteristic petrographic features of granites from the dam. (a) amphibole strongly replaced by titanite, epidote, chlorite and biotite, +n. (b) biotite with zircon inclusions, +n. (c) bse image of euhedral allanite crystal in k-feldspar. (d) monazite grains in k-feldspar and plagioclase, +n. mineral abbreviations are after kretz (1983). geologia croatica 68/1geologia croatica 54 ta bl e 1: r ep re se nt at iv e bi ot ite c om po si tio ns o f g ra ni te s f ro m th e d itr ău a lk al in e m as si f, ro m an ia . sa m pl e vr g 68 35 vr g 68 35 vr g 68 35 vr g 68 35 vr g 68 35 vr g 68 35 vr g 68 35 vr g 68 35 vr g 68 35 vr g 68 35 vr g 68 35 vr g 68 39 vr g 68 39 vr g 68 39 vr g 68 39   1 2 3 4 5 6 7 8 9 10 11 1 2 3 4 si o 2 35 .3 0 36 .6 0 35 .4 1 36 .3 2 36 .2 5 38 .1 4 36 .3 1 35 .2 1 36 .5 5 36 .7 7 36 .8 3 37 .4 0 37 .2 9 37 .3 6 35 .9 4 ti o 2 2. 66 1. 35 1. 99 2. 11 2. 53 2. 44 2. 59 3. 17 3. 00 3. 40 2. 99 3. 13 2. 74 3. 23 2. 96 al 2o 3 12 .9 5 13 .3 8 13 .5 5 12 .9 5 13 .8 4 13 .4 7 13 .2 1 13 .3 2 13 .5 9 13 .1 4 13 .5 9 13 .0 1 13 .3 4 12 .6 1 12 .1 8 fe o 22 .8 6 23 .0 6 23 .0 4 22 .9 4 22 .9 3 23 .2 0 24 .1 1 23 .2 9 23 .4 4 24 .8 8 24 .7 2 21 .5 1 21 .2 3 21 .8 7 20 .6 7 m no 0. 82 0. 78 0. 84 0. 84 0. 84 0. 46 0. 80 0. 84 0. 69 0. 82 0. 39 0. 54 0. 49 0. 44 0. 51 m go 8. 66 8. 80 8. 42 8. 26 8. 00 8. 71 8. 04 7. 22 7. 47 7. 31 7. 59 9. 63 9. 19 9. 24 9. 92 ca o 0. 02 0. 06 0. 12 0. 00 0. 03 0. 00 0. 02 0. 00 0. 00 0. 22 0. 14 0. 03 0. 00 0. 00 0. 10 n a 2 o 0. 53 0. 03 0. 18 0. 15 0. 03 0. 30 0. 34 0. 11 0. 21 0. 21 0. 07 0. 00 0. 33 0. 12 0. 40 k 2 o 9. 38 9. 94 9. 38 9. 34 9. 76 9. 95 10 .0 0 9. 60 9. 93 9. 61 9. 89 9. 62 9. 75 9. 79 9. 47 to ta l 93 .1 5 94 .0 0 92 .9 3 92 .6 7 94 .2 1 96 .6 6 95 .4 2 92 .7 6 94 .8 1 96 .3 5 86 .3 3 94 .8 7 94 .3 6 94 .6 6 92 .1 5 o xy ge ns 22 22 22 22 22 22 22 22 22 22 22 22 22 22 22 si 5. 67 5. 81 5. 70 5. 83 5. 74 5. 86 5. 72 5. 69 5. 76 5. 74 5. 74 5. 81 5. 83 5. 84 5. 77 al iv 2. 32 2. 18 2. 29 2. 16 2. 25 2. 13 2. 27 2. 30 2. 23 2. 25 2. 25 2. 18 2. 16 2. 15 2. 22 al vi 0. 13 0. 32 0. 27 0. 29 0. 32 0. 29 0. 18 0. 24 0. 28 0. 16 0. 24 0. 20 0. 28 0. 16 0. 08 ti 0. 32 0. 16 0. 24 0. 25 0. 30 0. 28 0. 30 0. 38 0. 35 0. 39 0. 35 0. 36 0. 32 0. 37 0. 35 fe 2+ 3. 07 3. 06 3. 10 3. 08 3. 03 2. 98 3. 18 3. 15 3. 08 3. 24 3. 22 2. 79 2. 77 2. 86 2. 77 m n 0. 11 0. 10 0. 11 0. 08 0. 11 0. 05 0. 10 0. 11 0. 09 0. 10 0. 05 0. 07 0. 06 0. 05 0. 06 m g 2. 07 2. 08 2. 02 1. 97 1. 88 1. 99 1. 89 1. 74 1. 75 1. 70 1. 76 2. 23 2. 14 2. 15 2. 37 ca 0. 00 0. 01 0. 02 0. 00 0. 00 0. 00 0. 00 0. 00 0. 01 0. 03 0. 02 0. 00 0. 00 0. 00 0. 01 n a 0. 17 0. 01 0. 05 0. 04 0. 01 0. 08 0. 10 0. 03 0. 06 0. 06 0. 00 0. 01 0. 10 0. 03 0. 12 k 1. 92 2. 01 1. 92 1. 91 1. 97 1. 95 2. 01 1. 98 1. 99 1. 91 1. 96 1. 90 1. 94 1. 95 1. 94 to ta l 15 .8 2 15 .7 7 15 .7 6 15 .1 6 15 .6 5 15 .6 5 15 .7 9 15 .6 5 15 .6 5 15 .6 3 15 .6 3 15 .5 7 15 .6 3 15 .6 0 15 .7 4 m g# 0. 40 0. 40 0. 39 0. 39 0. 38 0. 40 0. 37 0. 35 0. 36 0. 34 0. 35 0. 44 0. 43 0. 43 0. 46 fe /( fe +m g) 0. 60 0. 60 0. 61 0. 61 0. 62 0. 60 0. 63 0. 64 0. 64 0. 64 0. 65 0. 56 0. 56 0. 57 0. 54 m g/ fe 0. 67 0. 68 0. 65 0. 64 0. 62 0. 67 0. 59 0. 55 0. 57 0. 52 0. 55 0. 80 0. 77 0. 75 0. 86 pál-molnár et al.: geochemical implications for the magma origin of granitic rocks from the ditrău alkaline massif (eastern carpathians, romania) geologia croatica 55 euhedral to subhedral and is fineto coarse-grained (600–1000 µm). it shows albite twinning and often has a sericitized core. the mediumto very coarse-grained k-feldspar (500–4000 µm) is microcline occurring as tartan twins. exsolution textures are commonly represented by perthite and equilibrium quartz-feldspar intergrowth (i.e. myrmekite) occurring mainly in amphibole-bearing samples. myrmekite texture is developed at the margins of plagioclase and microcline. wormor finger-like droplets of quartz are enclosed in plagioclase. biotite appears as discrete subhedral to anhedral grains, as well as grain aggregates interstitial to feldspars and quartz (fig. 2b). it is often altered to chlorite, opaque minerals and hematite. accessory phases are apatite, zircon, monazite, ilmenite, magnetite and allanite. allanite generally occurs as euhedral to subhedral crystals interstitial to the major minerals (fig. 2c). it is strongly pleochroic (from red to brownish red). zircon (fig. 2b) and apatite are usually euhedral and are enclosed in biotite and feldspars. monazite is euhedral and incorporated in biotite or feldspars (fig. 2d). magnetite occurs as euhedral crystals and enclosed in amphiboles. allanite solely appears in granites which contain amphibole, whereas monazite appears only in amphibole-free varieties. 4.2. mineral chemistry 4.2.1. biotite representative microprobe analyses of biotites are given in table 1. they are annite according to deer et al. (1992). there are two types of biotites in the studied granites, one with higher mg# of 0.42–0.46 (mg/fe=0.75–0.86) and the other one with lower mg# of 0.34–0.40 (mg/fe=0.52–0.68). the high ti content (tio2=1.4–3.4 wt. %) is a characteristic features of biotites, and is similar to the biotites of other rocks from the ditrǎu alkaline massif (pál-molnár, 2000; morogan et al., 2000; batki et al., 2014). mg contents slightly decrease with increasing alvi (table 1). 4.2.2. amphibole representative chemical compositions of amphiboles are shown in table 2. according to leake et al. (1997) they are calcic amphiboles and compositionally vary between ferro-edenite and ferrohornblende (fig. 3). bca contents vary from 1.68 to 1.82, while bna content varies between 0.17–0.31. bna content shows positive correlation with mg#, while bca content increases with decreasing mg#. all amphiboles similar to biotites are iron rich. they have high fe/(fe+mg) ratios of 0.69–0.75. their aliv content ranges from 1.20 to 1.35 and the alvi values vary between 0.00–0.18. 4.2.3. feldspars representative analyses of feldspars are listed in table 3. feldspars represent both plagioclase and k-feldspar. plagioclase is mainly albite with composition of ab86an13or1 to ab98an1or1 (fig. 4). zoned plagioclase can not be observed. k-feldspar is orthoclase (or94-97). figure 3: compositional variations of amphiboles from the dam granites after leake et al. (1997). figure 4: plots of ab vs an vs or compositional diagram (fields from barker, 1979) for the dam granitic rocks. geologia croatica 68/1geologia croatica 56 5. major and trace element geochemistry geochemical data for the major element composition of the dam granites (two samples) were previously published by streckeisen (1954). morogan et al. (2000) also gave major, trace and ree data of three samples (table 4). in this study, new analyses for major, trace and rees include eleven granites. the dam granites are high in sio2, al2o3, feot (up to 3.1 wt. %) and alkalis (na2o+k2o=8.2–11.5 wt. %), and generally low in cao (table 4). the mgo content of amphibolebearing granites varies from 0.47 to 0.84. mg values are very low for all of the samples. the studied granites are mostly alkaline (fig. 5a) and strongly peraluminous in composition (asi>1; fig. 5b). feot, mgo, cao and tio2 decrease with increasing sio2 suggesting the fractionation of amphibole and ilmenite (not shown, table 4). they may also account for the high nb concentrations (up to 429 ppm). decreasing amounts of al2o3, p2o5 and zr with increasing sio2 could be controlled by the early extraction of allanite, apatite and zircon, respectively. k2o values are constant with increasing sio2 as a table 2: representative amphibole compositions of granites from the ditrău alkaline massif, romania. sample vrg6835 vrg6835 vrg6835 vrg6835 vrg6835 vrg6835 vrg6835 vrg6835 vrg6835 mineral fe2-ed fe2-ed fe2-hbl fe2-ed fe2-ed fe2-ed fe2-hbl fe2-ed fe2-ed sio2 42.50 43.09 43.39 42.65 43.34 41.88 42.94 43.38 41.66 tio2 1.70 1.36 1.64 1.30 1.06 1.36 1.74 1.50 1.26 al2o3 7.91 7.88 7.23 7.22 7.30 7.64 7.77 7.54 8.15 feot 24.70 25.74 25.24 24.98 24.21 24.27 24.76 24.79 25.40 feo 20.47 20.05 18.52 21.10 22.08 21.42 17.43 21.43 22.31 fe2o3 4.69 6.31 7.45 4.30 2.36 3.16 8.14 3.72 3.43 mno 1.02 1.12 1.20 1.18 1.17 1.24 1.10 0.80 1.17 mgo 5.70 5.64 6.40 5.96 5.66 5.30 5.99 5.49 4.71 cao 10.62 10.62 10.24 10.67 10.54 10.24 10.20 10.26 10.67 na2o 1.69 1.63 1.96 2.23 2.12 2.26 1.10 1.93 1.66 k2o 1.12 1.16 1.06 1.07 1.13 1.05 1.11 0.97 1.45 total 96.96 98.87 98.36 97.26 96.76 95.24 96.71 96.66 96.13 oxygens 23 23 23 23 23 23 23 23 23 tsi 6.64 6.64 6.65 6.68 6.76 6.70 6.64 6.79 6.64 ∑ al 1.46 1.44 1.30 1.33 1.34 1.44 1.41 1.38 1.53 tal 1.35 1.28 1.30 1.31 1.23 1.29 1.35 1.20 1.35 cal 0.11 0.16 0.00 0.02 0.11 0.15 0.06 0.18 0.18 cti 0.20 0.15 0.18 0.15 0.12 0.16 0.20 0.17 0.15 fetot 3.22 3.31 3.23 3.26 3.19 3.25 3.19 3.23 3.38 cfe3+ 0.55 0.73 0.86 0.50 0.28 0.38 0.94 0.43 0.41 cmg 1.32 1.31 1.46 1.39 1.31 1.26 1.38 1.28 1.12 cfe2+ 2.67 2.58 2.37 2.76 2.91 2.87 2.25 2.80 2.97 cmn 0.13 0.14 0.15 0.15 0.15 0.16 0.14 0.10 0.15 bca 1.78 1.77 1.68 1.79 1.76 1.75 1.69 1.72 1.82 ∑ na 0.51 0.49 0.57 0.67 0.63 0.69 0.32 0.58 0.50 bna 0.22 0.22 0.31 0.20 0.23 0.24 0.30 0.27 0.17 ana 0.29 0.27 0.26 0.47 0.40 0.45 0.02 0.31 0.33 ak 0.22 0.23 0.20 0.21 0.22 0.21 0.21 0.19 0.29 total cat 20.66 20.71 20.52 20.89 20.64 21.00 20.10 20.63 15.77 mg# 0.33 0.34 0.38 0.33 0.31 0.31 0.38 0.31 0.27 fe/(fe+mg) 0.71 0.72 0.69 0.70 0.71 0.72 0.70 0.72 0.75 fe2-ed: ferro-edenite; fe2-hbl: ferrohornblende; feotot: total iron; mg# (mg/(mg+fe2+) pál-molnár et al.: geochemical implications for the magma origin of granitic rocks from the ditrău alkaline massif (eastern carpathians, romania) geologia croatica 57 ta bl e 3: r ep re se nt at iv e fe ld sp ar c om po si tio ns o f g ra ni te s f ro m th e d itr ău a lk al in e m as si f, ro m an ia . sa m pl e vr g 68 35 vr g 68 35 vr g 68 35 vr g 68 35 vr g 68 35 vr g 68 35 vr g 68 35 vr g 68 35 vr g 68 35 vr g 68 39 vr g 68 39 vr g 68 39 vr g 68 39 vr g 68 39 vr g 68 39 vr g 68 39 vr g 68 39 m in er al pl 1 pl 2 pl 3 pl 4 pl 5 m c1 m c2 m c3 m c4 pl 1 pl 2 pl 3 pl 4 pl 5 pl 6 pl 7 pl 8 si o 2 68 .4 0 67 .0 8 65 .5 0 67 .4 8 65 .8 6 64 .6 2 64 .7 6 64 .1 8 64 .6 7 65 .7 2 64 .2 7 65 .4 2 65 .4 4 66 .1 2 66 .3 8 66 .7 1 65 .8 4 ti o 2 0. 05 0. 17 0. 16 0. 13 0. 01 0. 13 0. 01 0. 28 0. 12 — 0. 10 0. 10 0. 02 0. 02 — 0. 06 0. 01 al 2o 3 19 .3 9 20 .3 5 20 .9 0 20 .6 2 20 .2 6 16 .9 5 17 .6 7 18 .2 8 17 .3 6 21 .2 3 21 .3 4 21 .0 3 20 .6 8 20 .5 9 20 .9 0 20 .5 8 20 .8 2 fe o 0. 03 0. 11 0. 36 0. 29 0. 18 0. 28 0. 14 0. 23 0. 03 — 0. 28 — — 0. 13 0. 12 — — m no — 0. 28 0. 10 0. 12 0. 02 0. 04 0. 10 — 0. 18 0. 33 — 0. 18 — — 0. 08 — 0. 09 m go 0. 10 0. 08 0. 16 0. 07 0. 02 0. 17 0. 08 — 0. 01 0. 08 — — — — 0. 02 — 0. 04 ca o 0. 13 0. 98 2. 23 0. 98 1. 35 0. 05 0. 03 0. 32 0. 13 2. 45 2. 79 2. 39 2. 60 2. 33 1. 67 2. 02 2. 10 n a 2 o 11 .0 7 10 .9 2 10 .2 8 11 .3 0 9. 54 0. 27 0. 26 0. 47 0. 50 9. 84 9. 81 9. 93 9. 44 9. 76 10 .2 5 10 .6 4 9. 99 k 2 o 0. 13 0. 10 0. 15 0. 06 0. 04 16 .5 8 16 .5 2 17 .0 8 16 .8 2 0. 19 0. 15 0. 05 0. 21 0. 15 0. 18 0. 06 0. 15 to ta l 99 .3 0 99 .9 1 99 .8 4 10 0. 67 96 .8 2 99 .0 9 99 .2 1 10 0. 39 98 .9 1 99 .8 4 98 .6 5 99 .0 9 98 .4 2 99 .1 1 99 .6 1 10 0. 06 99 .0 3 o xy ge ns 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 si 3. 00 2. 94 2. 89 2. 93 2. 95 3. 02 3. 01 2. 97 3. 02 2. 89 2. 87 2. 90 2. 91 2. 92 2. 92 2. 92 2. 91 ti 0. 00 0. 01 0. 01 0. 00 0. 00 0. 01 0. 00 0. 01 0. 00 — 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 al 1. 00 1. 05 1. 08 1. 05 1. 07 0. 93 0. 97 0. 99 0. 95 1. 10 1. 12 1. 10 1. 08 1. 07 1. 08 1. 06 1. 08 fe 0. 00 0. 00 0. 01 0. 01 0. 01 0. 01 0. 01 0. 01 0. 00 — 0. 01 — — 0. 01 0. 00 0. 00 0. 00 m n 0. 00 0. 01 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 01 0. 01 0. 00 0. 01 0. 00 0. 00 0. 00 0. 00 0. 00 m g 0. 01 0. 01 0. 01 0. 01 0. 00 0. 01 0. 01 0. 00 0. 00 0. 01 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 ca 0. 01 0. 04 0. 10 0. 04 0. 06 0. 00 0. 00 0. 01 0. 01 0. 11 0. 13 0. 11 0. 12 0. 11 0. 07 0. 09 0. 09 n a 0. 94 0. 92 0. 87 0. 95 0. 82 0. 02 0. 02 0. 04 0. 04 0. 84 0. 85 0. 85 0. 81 0. 83 0. 87 0. 90 0. 85 k 0. 01 — 0. 01 — — 0. 99 0. 98 1. 01 1. 00 0. 01 0. 01 0. 00 0. 01 0. 01 0. 01 0. 01 to ta l 4. 96 4. 99 5. 00 5. 00 4. 92 5. 00 4. 99 5. 04 5. 02 4. 97 4. 99 4. 97 4. 95 4. 95 4. 97 4. 99 4. 97 m ol %                                   o r 0. 75 0. 56 0. 84 0. 32 0. 24 97 .3 4 97 .5 3 94 .5 7 95 .6 8 6. 54 0. 86 0. 28 1. 25 0. 89 1. 04 0. 32 0. 88 ab 98 .6 1 94 .7 4 88 .5 4 95 .1 1 92 .5 2 2. 40 2. 32 3. 94 4. 31 82 .1 6 85 .6 7 88 .0 1 85 .7 0 87 .5 6 90 .7 8 90 .2 1 88 .8 1 an 0. 63 4. 69 10 .6 1 4. 55 7. 22 0. 24 0. 13 1. 48 0. 00 11 .3 0 13 .4 6 11 .7 0 13 .0 4 11 .5 5 8. 16 9. 45 10 .3 2 pl : p la gi oc la se ; m c: m ic ro cl in e geologia croatica 68/1geologia croatica 58 ta bl e 4: w ho le -r oc k an al ys es o f g ra ni te s f ro m th e no rt he rn p ar t o f t he d itr ău a lk al in e m as si f, ro m an ia . lo ca tio n la po sbü kk cr ee k la po sbü kk cr ee k la po sb ük k cr ee k tu rc ul ui cr ee k tu rc ul ui cr ee k cr ea ng ă m ar e cr ee k cr ea ng ă m ar e cr ee k cr ea ng ă m ar e cr ee k ţe ng he le r m ic c re ek h ol oş ag cr ee k tu rc ul ui cr ee k h ol oş ag cr ee k m ag as bü kk cr ee k jo lo tc a cr ee k jo lo tc a cr ee k jo lo tc a cr ee k w h a le n et a l., 19 87 sa m pl e vr g 68 35 vr g 68 39 vr g 68 38 /a vr g 74 59 vr g 74 60 vr g 68 47 vr g 68 56 vr g 67 26 vr g 68 42 vr g 74 25 /a vr g 74 58 st re ck ei se n , 1 95 4 m o ro g a n e t a l., 2 00 0 av er ag e of 1 48 sa m pl es 1 2 d t 11 4 d t 11 2 d t 13 4 w t. % am ph ib ol ebe ar in g gr an ite s  am ph ib ol efre e gr an ite s  gr an ite s gr an ite s si o 2 71 .7 0 67 .4 67 .4 2 70 .1 2 65 .2 1 77 .1 70 .2 68 .7 3 74 .2 2 78 .4 4 76 .5 4 73 .4 5 71 .2 9 71 .4 7 71 .9 3 74 .2 7 73 .8 1 al 2o 3 14 .8 6 16 .5 0 16 .0 2 14 .9 9 16 .6 3 13 .3 4 14 .2 7 16 .2 9 14 .3 4 11 .4 4 12 .4 4 14 .0 1 15 .8 7 14 .6 9 14 .6 3 13 .6 5 12 .4 0 ti o 2 0. 40 0. 45 0. 50 0. 17 0. 55 0. 09 0. 16 0. 21 0. 12 0. 11 0. 05 0. 14 0. 60 0. 22 0. 16 0. 11 0. 26 fe o t 2. 00 3. 06 3. 10 2. 59 3. 48 1. 24 1. 84 2. 12 0. 61 0. 80 1. 20 2. 13 1. 35 1. 83 1. 98 1. 15 — fe 2o 3 0. 36 0. 53 0. 54 0. 40 0. 53 0. 20 0. 30 0. 35 0. 11 0. 14 0. 18 0. 32 0. 21 0. 31 0. 32 0. 19 1. 24 fe o 1. 48 2. 28 2. 30 1. 98 2. 65 0. 94 1. 39 1. 59 0. 45 0. 60 0. 92 1. 62 1. 03 1. 37 1. 49 0. 86 1. 58 m go 0. 47 0. 65 0. 84 0. 15 0. 63 0. 13 0. 27 0. 18 0. 17 0. 09 0. 07 0. 00 0. 18 0. 15 0. 17 0. 14 0. 20 m no 0. 06 0. 07 0. 09 0. 14 0. 09 0. 02 0. 08 0. 05 — 0. 02 0. 02 0. 02 0. 01 0. 06 0. 05 0. 03 0. 06 ca o 0. 77 0. 96 0. 76 0. 25 2. 01 0. 12 0. 29 0. 15 0. 59 0. 24 0. 15 0. 46 0. 10 0. 68 0. 32 0. 18 0. 75 n a 2 o 4. 59 5. 02 5. 94 6. 17 4. 74 4. 67 4. 41 5. 88 4. 30 2. 79 3. 75 5. 95 5. 05 4. 53 4. 68 4. 07 4. 07 k 2 o 4. 74 5. 28 3. 97 4. 48 5. 55 4. 59 5. 32 5. 58 4. 90 5. 42 5. 21 3. 67 4. 96 5. 17 5. 25 5. 51 4. 65 p 2 o 5 — — 0. 14 0. 02 0. 16 — — 0. 05 0. 07 0. 05 0. 01 0. 08 — 0. 04 0. 02 0. 09 0. 04 to ta l 10 1. 43 10 2. 20 10 1. 62 99 .9 2 99 .7 5 10 2. 44 98 .5 3 10 1. 18 99 .8 8 10 0. 14 99 .5 0 10 1. 85 10 0. 65 10 0. 52 10 1. 00 10 0. 25 99 .0 6 a /n k 1. 6 1. 6 1. 6 1. 4 1. 6 1. 4 1. 5 1. 4 1. 6 1. 4 1. 4 1. 5 1. 6 1. 5 1. 5 1. 4 1. 4 n k/ a 0. 6 0. 6 0. 6 0. 7 0. 6 0. 7 0. 7 0. 7 0. 6 0. 7 0. 7 0. 7 0. 6 0. 7 0. 7 0. 7 0. 7 a /c n k 1. 47 1. 47 1. 50 1. 38 1. 35 1. 42 1. 42 1. 40 1. 46 1. 35 1. 37 1. 39 1. 57 1. 42 1. 43 1. 40 1. 31 m g# 19 .0 17 .5 21 .3 5. 5 15 .3 9. 5 12 .8 7. 8 21 .8 10 .1 5. 5 0. 0 11 .8 7. 6 7. 9 10 .9 — m g# (1 00 (m go /m go +f eo )); a /n k: a l 2o 3/ (n a 2 o +k 2o ); n k/ a : ( n a 2 o +k 2o )/ al 2o 3; a /c n k: a l/( ca +n a+ k) pál-molnár et al.: geochemical implications for the magma origin of granitic rocks from the ditrău alkaline massif (eastern carpathians, romania) geologia croatica 59 ta bl e 4. (c on tin ue d) lo ca tio n la po sb ük k cr ee k la po sb ük k cr ee k la po sb ük k cr ee k tu rc ul ui cr ee k tu rc ul ui cr ee k cr ea ng ă m ar e cr ee k cr ea ng ă m ar e cr ee k cr ea ng ă m ar e cr ee k ţe ng he le r m ic c re ek h ol oş ag cr ee k tu rc ul ui cr ee k jo lo tc a cr ee k jo lo tc a cr ee k jo lo tc a cr ee k w h a le n e t al .,1 98 7 sa m pl e vr g 68 35 vr g 68 39 vr g 68 38 /a vr g 74 59 vr g 74 60 vr g 68 47 vr g 68 56 vr g 67 26 vr g 68 42 vr g 74 25 /a vr g 74 58 m o ro g a n e t a l., 2 00 0 av er ag e of 1 48 sa m pl es d t 11 4 d t 11 2 d t 13 4 pp m am ph ib ol ebe ar in g gr an ite s am ph ib ol efre e gr an ite s gr an ite s be 6. 45 2. 9 2 2. 00 6. 00 6. 1 4. 5 11 3 3 5. 00 — — — — sc 1. 8 3. 6 3 1. 00 2. 00 0. 4 1. 5 1 2 1 1. 00 0. 1 2. 3 7. 0 4 v 13 23 .5 29 12 .0 0 22 .0 0 2 5. 5 — — <8 8. 00 11 .0 7. 0 9. 0 6 cr 4. 14 13 — — — 4 17 — — — — 0. 0 0. 0 0. 0 — co 4. 17 5. 02 3 1. 10 3. 90 6. 2 7. 05 0. 8 1. 2 0. 9 0. 80 — — — — n i 4. 1 11 .9 2. 8 1. 90 2. 90 4. 7 9. 4 1. 3 3 0. 6 2. 80 2. 0 2. 0 3. 0 <1 cu 33 16 2. 7 3. 70 3. 80 15 20 3. 5 1. 7 3. 2 5. 10 2. 0 0. 0 0. 0 2 zn 34 2. 5 77 27 .0 0 48 .0 0 21 49 .5 5 92 10 17 11 .0 0 29 .0 42 .0 13 .0 12 0 sr 17 3 23 0 25 0 52 .7 0 54 4. 30 13 43 52 .9 95 .3 10 2. 8 32 .6 0 86 .0 42 .0 24 .0 48 ba 29 3 43 3 49 3 10 2. 00 81 6. 00 32 18 0 11 0 17 4 22 2 61 .0 0 15 4. 0 11 3. 0 13 3. 0 35 2 rb 44 4 31 8 87 .4 14 7. 80 17 8. 30 10 05 40 3 25 0. 6 17 0. 1 23 4. 9 25 6. 40 15 2. 0 15 4. 0 30 9. 0 16 9 zr 24 1 30 6 37 5. 1 28 2. 30 34 4. 30 14 0 69 0 51 0. 8 25 3. 1 12 4. 6 13 8. 90 34 8. 0 36 0. 0 13 9. 0 52 8 pb 7 10 .5 4. 1 2. 90 6. 30 17 .4 3. 9 6. 7 2. 6 6 6. 30 8. 7 14 .0 17 .0 24 th — — 28 .8 17 .1 0 22 .2 0 — — 28 .2 38 .8 26 .4 42 .9 0 28 .0 30 .0 15 .0 23 u — — 2. 4 3. 40 3. 60 — — 6 4. 8 2. 6 11 .1 0 — — — 5 n b 73 82 95 .2 10 9. 90 71 .9 0 42 9 14 7 10 3. 6 39 .2 53 .5 15 8. 90 97 .0 89 .0 50 .0 37 ta — — 5. 2 6. 00 5. 20 — — 4. 2 2. 6 3. 5 10 .6 0 5. 3 3. 9 2. 0 — y 13 .5 18 .5 24 .9 12 .5 0 22 .0 0 19 18 .5 13 .5 34 .5 11 .3 22 .6 0 17 .0 20 .0 25 .0 75 h f 1. 8 2. 6 9. 2 7. 50 7. 70 5. 8 19 11 .9 7. 5 3. 4 5. 80 — — — — m o — — 0. 1 0. 60 1. 60 5. 1 4. 2 0. 4 0. 3 0. 2 0. 50 — — — — la 37 .8 60 .2 89 .1 30 .8 0 41 .3 0 — 11 2. 5 78 .3 66 .8 49 .5 23 .7 0 71 .0 12 0. 0 25 .0 — ce 70 .6 12 1. 6 17 6. 5 94 .3 0 90 .2 0 38 .1 28 1. 4 17 1. 6 11 3. 9 83 .9 40 .4 0 13 2. 0 18 9. 0 43 .0 13 7 pr — — 14 .7 5 6. 00 7. 95 — — 12 .7 9 10 .8 7 8. 04 4. 40 — 21 .0 4. 3 — n d 14 .5 25 .5 46 .8 19 .3 0 28 .5 0 5. 5 38 .5 39 .9 34 .1 24 .3 15 .3 0 33 .0 61 .0 13 .0 — sm 5. 1 7. 6 7. 65 3. 50 5. 37 4. 8 11 .5 5. 84 6. 08 3. 86 3. 93 — 8. 6 3. 1 — eu 0. 6 1. 05 1. 4 0. 23 1. 49 0. 2 0. 6 0. 48 0. 79 0. 49 0. 19 — 0. 6 0. 3 — g a 20 .0 5 23 .1 21 .1 25 .1 0 22 .2 0 26 .5 29 .2 25 .3 18 .8 18 .4 22 .5 0 — — — 24 .6 g d 4. 6 7. 3 5. 53 2. 77 4. 50 3. 6 8. 9 4. 39 4. 96 2. 87 3. 70 — 5. 2 3. 3 — tb — — 0. 82 0. 43 0. 70 — — 0. 56 0. 88 0. 43 0. 71 — — h o — — 0. 85 0. 45 0. 70 — — 0. 49 1. 07 0. 37 0. 83 — 0. 7 0. 8 — er — — 2. 52 1. 33 1. 87 — — 1. 46 3. 3 0. 98 2. 26 — — — — tm — — 0. 38 0. 24 0. 30 — — 0. 24 0. 53 0. 15 0. 37 — — — — d y 2. 3 3. 5 4. 66 2. 49 3. 91 3. 5 3. 4 2. 91 4. 79 2. 17 4. 42 — 3. 6 3. 7 — yb 1. 3 1. 7 2. 2 1. 75 1. 94 2 2. 1 1. 61 3. 57 1. 07 2. 26 — 2. 0 2. 4 — lu — — 0. 35 0. 27 0. 30 — — 0. 28 0. 55 0. 14 0. 31 — — — — σr ee 15 6. 9 25 1. 6 37 4. 6 18 9. 0 21 1. 2 84 .2 48 8. 1 34 6. 2 27 1. 0 19 6. 7 12 5. 3 23 6. 0 41 1. 7 98 .9 — geologia croatica 68/1geologia croatica 60 result of continuous k-feldspar fractionation during differentiation, but na2o has a slight negative correlation with sio2 from 70 w. %,, consistent with the late stage of albite crystallization (not shown, table 4). ce increases up to an sio2 content of about 70 w. % and then decreases in the granites, suggesting later fractionation of monazite. v shows the same pattern as tio2 due to ilmenite fractionation (not shown, table 4). amphibole-bearing granites own higher sr (up to 544ppm) and ba (up to 816 ppm) contents than the amphibole-free varieties (sr < 103ppm, ba < 222ppm). primitive mantle-normalized granites display strong negative ba, sr and eu anomalies (eu/eu* = 0.15–0.66) (fig. 6a). the primitive mantle-normalized ree (fig. 6b) patterns show strong enrichment in lree and significant fractionation of hree with an (la/yb)n ratio of 13–38 (table 4). the (la/yb)n ratios are influenced by the enrichment of hree. the rocks have high mree content, especially sm and gd. ba, sr, zr, and sc decrease with increasing sio2 (not shown, table 4). the y/nb ratios are up to 0.88. 6. discussion 6.1. mantle source and geodynamic implications many types of granitoid classification have been proposed in the literature. these classifications divide granitoids mostly on the basis of their petrography (e.g. pupin, 1980; lameyre & bowden, 1982; nachit et al., 1985; tischendorf & palchen, 1985), geochemistry (chapell & white, 1974; pupin, 1980; collins et al., 1982; pearce et al., 1984; whalen et al., 1987) and tectonic environment (pitcher, 1983). essentially all of these classifications broadly correspond to the three possible sources of granitoids: crustal, mantle-derived and mixed (barbarin, 1990). the petrogenetic model developed for granitoid rocks by loiselle & wones (1979) and white & chapell (1983) contain four types of granitoids (s, i-, m-, and a-type) which also overlap with the crustal, mantle-derived and mixed origin of granitoids. the a-type granitoids occur along rift zones (loiselle & figure 5: standard discrimination diagrams showing that the dam granites are alkaline and strongly peraluminous. (a) a.r. vs sio2 diagram where a.r. (alkalinity ratio)=[al2o3+cao+(na2o+k2o)] /[al2o3+cao–(na2o+k2o)] (wt.% ratio). compositional fields are from wright (1969) and maniar & piccoli (1982). (b) a/nk vs a/cnk diagram for the dam granitic rocks. figure 6: plots of (a) trace element and (b) rare-earth element abundances normalised to primitive mantle (sun & mcdonough, 1989) for the dam granites. pál-molnár et al.: geochemical implications for the magma origin of granitic rocks from the ditrău alkaline massif (eastern carpathians, romania) geologia croatica 61 wones, 1979). according to whalen et al. (1987) atype granites can be separated from iand s-type granites based on their ga/al ratios and the fractionation of accessory phases. the average composition of a-type granites (whalen et al., 1987) is also presented in table 4. the dam granites exhibit high zr+nb+ce+y content (>350 ppm) and ga/al ratios indicating a-type characteristics of the rocks (fig. 7). furthermore, the dam granites fulfil the compositional criteria (loiselle & wones, 1979; whalen et al., 1987) for identifying them as a-type granites with high concentrations of sio2, na2o+k2o, zr, nb, ga, y, ce and fe/mg ratios, and low cao, sr and ba contents (table 4). as suggested by several authors a-type granites can be formed in different ways (collins et al., 1982; whalen et al., 1987; eby, 1990; frost & frost, 1997; bonin, 2007). generally, models for the petrogenesis of a-type magmas are as follows: (1) fractionation of mantle-derived basaltic magmas (eby, 1990; bonin, 2007); (2) mantle-derived magmas may assimilate crustal material during their ascent to produce a syenitic derivative that fractionates to a granitic composition (poitrasson et al., 1995; barth, 1945); (3) this syenitic magma can also form granite with a mixed source characteristic due to further assimilation (barker et al., 1975); (4) melting of crustal material, namely low degrees of partial melting of granulite that were depleted in incompatible elements by previous melt extraction (whalen et al., 1987; collins et al., 1982). eby (1992) subdivided anorogenic a-type granitoids into two groups: a1-type granites (y/nb<1.2) representing a mantle differentiate of continental rift-related and other intraplate environments, whilst a2-type granites (y/nb>1.2) derived from melting of underplated continental crust emplaced in a variety of tectonic environments (e.g. back-arcs, collision, post-collision and transcurrent faults etc.). the studied granites have low y/nb ratio of 0.04-0.88 suggesting within-plate a1-type characteristics (fig. 8a) and emplacement in an extensional environment (fig. 8b). this also implies that they are mantle differentiates with sources corresponding to oib (fig. 9). figure 7: discrimination diagrams (a) (k2o+na2o)/cao vs zr+nb+ce+y and (b) nb vs 10000*ga/al after whalen et al. (1987) for the dam granites. ofg: unfractionated s-, mand i-type granitoids; fg: fractionated s-, mand i-type granitoids. figure 8: plots of incompatible trace elements (a) nb vs y vs 3ga distribution for subdivision of a-type granites following eby (1992) for the dam granites. (b) rb vs y+nb diagram after pearce et al. (1984) for granites from the dam. geologia croatica 68/1geologia croatica 62 the studied rocks are predominantly ferroan granites (table 4). according to frost & lindsley (1991) reduced basaltic rocks from extensional environments could undergo fe-enrichment or reduction through differentiation, whereas the relatively oxidized arc basaltic rocks could not. this implies that the dam granites originated from a reduced basaltic compositional source. according to frost & frost (2011) ferroan granitoids are principally peralkaline and metaluminous, however there are also ferroan granites with a peraluminous nature. the ferroan alkali granitoids with a peraluminous component, like the studied rocks, can occur owing to the greater amount of felsic crust assimilation compared to metaluminous granitoids (frost & frost, 2011). 6.2. geobarometry amphibole composition in plutonic rocks is commonly applied to determine the pressure of the crystallization and solidification of the pluton that can be used to determine the depth of the magma emplacement (e.g. vyhnal & mcsween, 1990; zhang et al. 2006; stein & dietl, 2001; papoutsa & pe-piper, 2014). after empirical notification of the al in amphibole barometer by hammarstrom & zen (1986) and hollister et al. (1987), experimental studies (e.g. johnson & rutherford, 1989a, b; thomas & ernst, 1990; schmidt, 1992) also confirmed that the al content of the amphibole can indicate the pressure of its crystallization. these studies found that the al content of the amphibole increases with increasing pressure due to the tschermak substitution si + r2+ = aliv + alvi. however, it is important to note that the composition of amphibole is sensitive for several parameters including the intensive parameters (p, t, fo2, fh2o), the cocrystallizing phases and the equilibrium melt composition. thus, amphibole can be used as a barometer if the thermodynamic degrees of freedom can be reduced. several criteria have to be met for accurate barometric calculations. the empirical studies indicate that a requisite mineral assemblage is necessary for hornblende barometry including quartz, plagioclase, k-feldspar, biotite, hornblende, fe-ti oxide and titanite, to buffer the amphibole composition (hollister et al., 1987; hammarstrom & zen, 1986; anderson & smith, 1995). the barometer has been calibrated experimentally for the assemblage quartz + plagioclase + kfeldspar + biotite + hornblende + fe-ti oxide + titanite + melt + fluid (johnson & rutherford, 1989a, b; thomas & ernst, 1990; schmidt, 1992). excluding titanite, all of these minerals can be found in the studied granites. the role of titanite is unknown but the study of anderson & smith (1995) did not find any correlation between the presence or absence of this phase and the calculated pressure. they concluded that either the activity of titanite was at a level sufficiently close to saturation so as to buffer al content in hornblende or not significantly affect the equilibria. titanite is sensitive for the oxygen-fugacity and was stable in high fo2 experiments of johnson & rutherford (1989a). the high fe/(fe+mg) and low fe3+/ (fe3++fe2+) ratio of the studied amphiboles suggest an intermediate/low fo2 for the crystallization condition of their host granite using the criteria of anderson & smith (1995). maybe the oxygen-fugacity was too low to stabilize titanite during the crystallization of the studied granites. anderson & smith (1995) found that amphiboles with an fe/(fe+mg) ratio higher than 0.6 yield anomalously higher pressures for proterozoic anorogenic granites than the former barometric constraints when the al-in-amphibole barometry was applied. according to the experiments of schmidt (1993) tschermak substitution preferentially removes mg from the m2 site instead of fe. anderson & smith (1995) suggested that the low fo2 during crystallization of these anorogenic granite magmas lowered the mg content of the amphiboles relative to fe2+ and forced tschermak substitution. this also accompanied fe3+ alvi exchange due to the low fe3+ relative to total fe. thus the higher fe/mg and low fe3+/(fe3++fe2+) ratio of the amphiboles may be related to the low fo2 during crystallization of those anorogenic granites which resulted in the elevated al content and the overestimation of the crystallization pressure. the amphiboles of the present study are characterized typically by low fe3+/(fe3++fe2+) (0.17±0.07) and high fe/ (fe+mg) (0.71±0.02) suggesting that the pressure values obfigure 9: rare earth and incompatible trace element ratios for the dam granites: (a) yb/ta vs y/nb and (b) ce/nb vs y/nb . fields for a1, a2, oib and iab are after eby (1992). pál-molnár et al.: geochemical implications for the magma origin of granitic rocks from the ditrău alkaline massif (eastern carpathians, romania) geologia croatica 63 tained from al in amphibole barometry can be viewed as a maximum. temperature can also affect the calculated pressure value through the edenite exchange that also increases the al content of the amphibole. to eliminate the influence of temperature, the recalibration of anderson & smith (1995) has been used which enables pressure calculations for igneous amphiboles that have been affected by the edenite substitution. hollister et al. (1987) suggested that the composition of the coexisting plagioclase should be in the range of an25-35 because the tschermak substitution is governed by a reaction involving 2 quartz + 2 anorthite + biotit = tschermakite + orthoclase. according to this reaction hollister et al. (1987) suggested that low anorthite content of the plagioclase lowers the al content of the amphibole. on the other hand humphreys et al. (2006) suggested that the plagioclase composition has a reverse effect on the al content of amphibole due to the edenite + albite = richterite + anortite reaction (holland & blundy, 1994). thus, a higher an content of the plagioclase lowers the al content of amphibole. the effect of the plagioclase composition on the al content of amphibole is unclear, but it should be taken into account because in the studied samples it falls out of the optimal range (an = 11 mol%). for the pressure calculation we used the spreadsheet of anderson et al. (2008) (rim69_ch04_hbld_plag_ thermo-jla.xls). this spreadsheet calculates pressure based on the al in amphibole barometer using the anderson & smith (1995) equation and temperature based on the amphibole-plagioclase thermometer (holland & blundy, 1994; blundy & holland, 1990). we used the “preferred” pressure values based on thermometer b of holland & blundy (1994), taking into account the study of anderson (1996). the calculated pressure value is 370 ± 40 mpa that corresponds to 14.1 ± 1.5 km depth using 2700 g/cm3 value for crustal density. as previously mentioned, above this pressure and depth, values can be interpreted as a maximum due to the higher fe/mg ratio of the studied amphiboles, however papoutsa & pe-piper (2014) indicated that amphiboles that have a higher fe/mg ratio than the recommended value may also give reasonable pressure values. the other factor that may lower the accuracy of our result comes from the ab-rich composition of the plagioclase, but the effect of this is not easy to quantitatively determine because of the opposite view of the effect of plagioclase composition on the al content of amphibole. the calcic amphiboles are not stable below ~100 mpa pressure according to experimental studies (e.g. rutherford & devine, 2003, 2008). we conclude that the studied granites were emplaced at middle or upper crustal levels at ~14 km depth or shallower, but deeper than the ~4 km stability depth of calcic amphiboles. 6.3. fractional crystallization geochemical characteristics of the dam granites indicate that they have formed as a result of strong fractional crystallization. the distribution of whole-rock major and trace elements (fig. 6, table 4) together with the petrographic observations suggest the fractionation of calcic amphibole, ilmenite, allanite, apatite and zircon in the early stage of evolution of the studied granites. during this stage, ce increases and starts to decrease from sio2 70 w%, which indicates crystallization of monazite. while k-feldspar crystallized continuously during differentiation, albite is a late stage product of the evolution. the fact that lree are enriched compared to hree indicates a fractionation between these elements. the presence of concave-up curvature in the pattern of hree may reflect either hree-rich fluid interaction or accumulation of zircon crystals (eby et al., 1998). since the most common accessory constituent is zircon, the most likely explanation for the upward hree patterns is the zircon accumulation. the studied rocks show significant negative ba, sr and eu anomalies (fig. 6a). plagioclase and amphibole fractionation produce negative sr and eu anomalies, whereas k-feldspar precipitation is responsible for the negative ba anomaly (wu et al., 2002). according to arslan & aslan (2006) the negative ba anomaly may be considered as evidence of high temperature feldspar fractionation rather than biotite precipitation. figure 6 shows that amphibole-bearing granite is distinct for eu, ba, and sr due to its smaller negative anomaly. the high content of sm and gd may reflect the early precipitation of perthitic feldspar (bowden & whitely, 1974), or crystallization of hornblende (kochhar, 2000), while the th anomaly is due to the presence of monazite and allanite. 7. conclusions beside a series of alkaline igneous rocks, a granite body also crops out in the dam. new whole-rock and mineral chemical data on the granites, together with the petrographic observations suggest the following implications. (1) dam granites are mostly alkaline and strongly peraluminous in composition. they are a-type granites with intra-plate a1-type characteristics indicated by their high zr, nb, ga, ce and y content and ga/al and fe/mg ratios, and by their low cao, sr and ba contents and y/nb ratios. (2) the a1-type nature implies that the studied granites are mantle differentiates with sources corresponding to oib and extensional environment. (3) the studied granites were probably emplaced at middle or upper crustal levels at about 14 km depth or shallower, but deeper than the ~4 km stability depth of calcic amphiboles indicated by the calculated crystallization pressure of 370 ± 40 mpa. (4) magmatic evolution of granites was mainly controlled by fractionation of calcic amphibole, ilmenite, allanite, apatite and zircon in the early stage and monazite and albite in a later stage of evolution. k-feldspar crystallized continuously during differentiation. (5) amphibole-bearing granites differ from the amphibole-free varieties in their lower sr, eu and ba anomalies which suggests their less fractionated character. geologia croatica 68/1geologia croatica 64 these observations confirm the mantle origin of the dam granites from a parental mafic magma together with fractional crystallization processes as assumed previously by morogan et al. (2000) and pál-molnár (2000). however, the peraluminous nature of the studied granites suggests the possibility of further assimilation and crustal contamination. acknowledgement we are grateful to gábor dobosi at the institute for geological and geochemical research, research centre for astronomy and earth sciences, hungarian academy of sciences for his help with the microprobe analyses. we thank carl-magnus mörth, birgitta boström and klára hajnal at stockholm university for their technical support in icp-ms and icp-aes analyses. we also thank marija horvat and an anonymous reviewer for constructive suggestions, which helped to improve the quality of this paper. funding for latter analyses was provided by the swedish institute in stockholm and the hungarian national science foundation (grant no. t046736). references anastasiu, n. & constantinescu, e. (1982): tectostructural position of the foidic rocks in the romanian carpathians.– revue roumaine géologie, géophysique, géographie, série géologie, 26. anderson, j.l. (1996): status of thermobarometry in granitic batholiths.– transactions of the royal society of edinburgh, 87, 125–138. anderson, j.l., barth, a.p., wooden, j.l. & mazdab, f. (2008): thermometers and thermobarometers in granitic systems.– reviews in mineralogy and geochemistry, 69/1, 121–142. anderson, j.l. & smith, d.r. (1995): the effects of temperature and o2 on the al-in-hornblende barometer.– american mineralogist, 80, 549–559. arslan, m. & aslan, z. (2006): mineralogy, petrography and wholerock geochemistry of the tertiary granitic intrusions in the eastern pontides, turkey.– journal of asian earth sciences, 27, 177–193. bagdasarian, g.p. (1972) despre vîrsta absolută a unor roci eruptive și metamorfice din masivul ditrău și munții banatului din românia [absolute age of eruptive and metamorphic rocks from ditrău and banat mountains in romania – in romanian].– studii şi cercetări geologie, geofizică, geografie, seria geologie, 17/1, 13–21. balintoni, i. (1981): the importance of the ditrau alcaline massif emplacement moment for dating of the basement overthrusts in the eastern carpathians.– revue roumaine géologie, géophysique, géographie, série géologie, 25, 89–94. balintoni, i (1997): geotectonica terenurilor metamorfice din românia [geotectonics of metamorphic area from romania – in romanian].– editura carpatica, cluj-napoca, 176 p. barbarin, b. (1990): granitoids: main petrogenetic classifications in relation to origin and tectonic setting.– geological journal, 25, 227–238. barker, f. (1979). trondhjemites: definition, environment and hypotheses of origin. – in: barker, f. (ed.): trondhjemites, dacites and related rocks, elsevier, amsterdam, 1–12. barker, f., wones, d.r., sharp, w.n. & desborough, g.a. (1975): the pikes peak batholith, colorado front range and a model for the origin of the gabbro-anorthosite-syenite-potassic granite suite.– precambria research, 2, 97–160. barth, t.f.w. (1945): studies of the igneous rock complex of the oslo region ii. systematic petrography of the plutonic rocks.– skrifter ardet norske videnskaps-akademi, oslo i matematisk-naturvidenskapelig klasse, l–104. batki, a., pál-molnár, e., dobosi, g. & skelton, a. (2014): petrogenetic significance of ocellar camptonite dykes in the ditrău alkaline massif, romania.– lithos, 200–201, 181–196. blundy, j.d. & holland, t.j.b. (1990): calcic amphibole equilibria and a new amphibole-plagioclase geothermometer.– contributions to mineralogy and petrology, 104/2, 208–224. bonin, b. (2007): a-type granites and related rocks: evolution of a concept, problems and prospects.– lithos, 97, 1–29. bowden, p. & whitely, j.e. (1974): rare earth patterns in peralkaline and associated granites.– lithos, 7, 15–21. chappell, b.w. & white, a.j.r. (1974): two contrasting granite types.– pacific geology, 8, 173–174. codarcea, a., codarcea, d.m. & ianovici, v. (1957): structura geologică masivului de roci alcaline de la ditrău [geological structure of alkaline rocks from the ditrău massif – in romanian].– buletinul ştiinţific al academiei republicii populare române, secţia de geologie și geografie, ii/3–4, 385–446. collins, w.j., beams, s.d., white, a.j.r. & chappell, b.w. (1982): nature and origin of atype granites with particular reference to southeastern australia.– contributions to mineralogy and petrology, 80, 189–200. dallmeyer, d.r., kräutner, h-g. & neubauer, f. (1997): middle-late triassic 40ar/39ar hornblende ages for early intrusions within the ditrau alkaline massif, rumania: implications for alpine rifting in the carpathian orogen.– geologica carpathica, 48, 347–352. deer, w.a., howie, r.a. & zussman, j. (1992): an introduction to the rock-forming minerals, 2nd edition.– longman scientific and technical, 696 p. eby, g.n. (1990): the a-type granitoids: a review of their occurrence and chemical characteristics and speculations on their petrogenesis.– lithos, 26, 115–134. eby, g.n. (1992): chemical subdivision of the a-type granitoids: petrogenetic and tectonic implications.– geology, 20, 641–644. eby, g.n., woolley, a.r., din, v. & platt, g. (1998): geochemistry and petrogenesis of nepheline syenites: kasungu-chipala, ilomba, and ulindi nepheline syenite intrusions, north nyasa alkaline province, malawi.– journal of petrology, 39, 1405–1424. fall, a., bodnar, r.j., szabó, cs. & pál-molnár, e. (2007): fluid evolution in the nepheline syenites of the ditrău alkaline massif, transylvania, romania.– lithos, 95, 331–345. frost, b.r. & lindsley, d.h. (1991): the occurrence of fe–ti oxides in igneous rocks. – in: lindsley, d.h. (ed.): oxide minerals: petrologic and magmatic significances, 25. mineralogical society of america, reviews in mineralogy, 433–486. frost, c.d. & frost, b.r. (1997): high-k, iron-enriched rapakivitype granites: the tholeiite connection.– geology, 25, 647–650. frost, c.d. & frost, b.r. (2011): on ferroan (a-type) granites: their compositional variability and modes of origin.– journal of petrology, 52, 39–53. hammarstrom, j.m. & zen, e. (1986). aluminum in hornblende: an empirical igneous geobarometer.– american mineralogy, 71, 1297–1313. hoeck, v., ionescu, c., balintoni, i. & koller, f.(2009) the eastern carpathians “ophiolites” (romania): remnants of a triassic ocean.– lithos, 108, 151–171. holland, t. & blundy, j. (1994): non-ideal interactions in calcic amphiboles and their bearing on amphibole-plagioclase thermometry.– contributions to mineralogy and petrology, 116, 433–447. pál-molnár et al.: geochemical implications for the magma origin of granitic rocks from the ditrău alkaline massif (eastern carpathians, romania) geologia croatica 65 hollister, l.s., grissom, g.c., peters, e.k., stowell, h.h. & sisson, v.b. (1987): confirmation of the empirical calibration of al in hornblende with pressure of solidification of calc-alkaline plutons.– american mineralogist, 72, 231–239. humphreys, m.c.s., blundy, j.d. & sparks, r.s.j. (2006): magma evolution and open-system processes at shiveluch volcano: insights from phenocryst zoning.– journal of petrology, 47/12, 2303–2334. ianovici, v. (1938): considérations sur la consolidation du massif syénitique de ditrău, en relation avec la tectonique de la région.– c. r. acad. sci. roum., ii/6, 689–694. jakab, gy. (1998): geologia masivului alcalin de la ditrău [geology of alkaline massif from ditrău – in romanian].– pallas-akadémia, miercurea-ciuc, 298 p. johnson, m.c. & rutherford, m.j. (1989a): experimental calibration of the aluminum-in-hornblende geobarometer with application to long valley caldera (california) volcanic rocks.– geology, 17, 837–841. johnson, m.c. & rutherford, m.j. (1989b): experimentally determined conditions in the fish canyon tuff, colorado, magma chamber.– journal of petrology, 30/3, 711–737. koch, a. (1879): a ditrói syenittömzs kőzettani és hegyszerkezeti viszonyairól [petrographical and structural aspects of the ditrău syenite – in hungarian].– magyar tudományos akadémiai értekezések, ix/2. kochhar, n. (2000): attributes and significance of the a-type malani magmatism, northwestern peninsular india.– in: deb, m. (ed.): crustal evolution and metallogeny in the northwestern india shield. narosa publishers, new delhi, 158–188. kovács, g. & pál-molnár, e. (2005): a ditrói alkáli masszívum granitoid kőzeteinek petrogenezise [petrogenesis of granitoid rocks from the ditrău alkaline massif – in hungarian].– földtani közlöny, 135/1, 121–143. kozur, h. (1991): the evolution of the meliata-hallstatt ocean and its significance for the early evolution of the eastern alps and western carpathians.– palaeogeography, palaeoclimatology, palaeoecology, 87/1–4, 109–135. kretz, r. (1983): symbols for rock-forming minerals.– american mineralogist, 68, 277–279. kräutner, h.g. & bindea, g. (1998): timing of the ditrău alkaline intrusive complex (eastern carpathians, romania).– slovak geological magazine, 4, 213–221. lameyre, j. & bowden, p. (1982): plutonic rock types series: discrimination of various granitoid series and related rocks.– journal of volcanology and geothermal research, 14, 169–186. leake, b.e., woolley, a.r., birch, w.d., arps, c.e.s., gilbert, m.c., grice, j.d., hawthorne, f.c., kato, a., kisch, h.j., krivovichev, v.g., linthout, k., laird, j. & mandarino, j. (1997): nomenclature of amphiboles: report of the subcommittee on amphiboles of the international mineralogical association commission on new minerals and mineral names.– mineralogical magazin, 61, 295–321. loiselle, m.c. & wones, d.r. (1979): characteristics and origin of anorogenic granites.– annual meetings of the geological society of america and associated societies, san diego, ca 11, 468. maniar, p.d. & piccoli, p.m. (1989): tectonic discrimination of granitoids.– geological society of america bulletin, 101, 635–643. morogan, v., upton, b.g.j. & fitton j.g. (2000): the petrology of the ditrău alkaline complex, eastern carpathians.– mineralogy and petrology, 69, 227–265. nachit, h., razafimahefa, n., stussi, j.m. & carron, j.p. (1985): composition chimique des biotites et typologie magmatique des granitoids.– comtes rendus hebdomadaires de l’ academie des sciences, 301/11, 813–818. pál-molnár, e. (1992): petrographical characteristics of ditró (orotva) hornblendites, eastern charpatians, transylvania (romania): a preliminary description.– acta mineralogica-petrographica, 33, 67–80. pál-molnár, e. (1994a): petrographical characteristics of ditró (orotva) diorites, eastern charpathians, transylvania (romania).– acta mineralogica-petrographica, 34, 95–109. pál-molnár, e. (1994b): a ditrói szienitmasszívum kialakulása a földtani megismerés tükrében [formation of the ditrău syenite massif in view of geological aspects – in hungarian].– a magyar tudományos akadémia szegedi akadémiai bizottságának kiadványai, szeged, 85 p. pál-molnár, e. (2000): hornblendites and diorites of the ditrău syenite massif.– department of mineralogy, geochemistry and petrology, university of szeged, szeged, 172 p. pál-molnár, e. (2006): granitoids from the ditrău alkaline massif, transylvania, romania.– geolines, 20, 103–104. pál-molnár, e. (2010): geology of székelyland.– in: szakáll, s. & kristály, f. (eds.): mineralogy of székelyland, eastern transylvania, romania. csík county nature and conservation society, sfântu gheorghe, miercurea ciuc, târgu mureş, 33–43. pál-molnár, e. & árva-sós, e. (1995): k/ar radiometric dating on rocks from the northern part of the ditrău syenite massif and its petrogenetic implications.– acta mineralogica-petrographica, 36, 101–116. papoutsa, a. & pe-piper, g. (2014): geochemical variation of amphiboles in a-type granites as an indicator of complex magmatic systems: wentworth pluton, nova scotia, canada.– chemical geology, 384, 120–134. pearce, j.a., harris, n.b.w. & tindle, a.g. (1984): trace element discrimination diagrams for the tectonic interpretation of granitic rocks.– journal of petrology, 25, 956–983. pitcher, w.s. (1983): granite type and tectonic environment.– in: hsu, k. (ed.): mountain building processes. academic press, london, 19–40. poitrasson, f., duthou, j.l. & pin, c. (1995): the relationship between petrology and nd isotopes as evidence for contrasting anorogenic granites gneiss: example of the corsican province (se france).– journal of petrology, 36, 1251–1274. pupin, j.p. (1980): zircon and granite petrology.– contribution to mineralogy and petrology, 73, 207–220. rutherford, m.j. & devine, j.d. (2003): magmatic conditions and magma ascent as indicated by hornblende phase equilibria and reactions in the 1995–2002 soufrie`re hills magma.– journal of petrology, 44/8, 1433–1453. rutherford, m.j. & devine, j.d. (2008): magmatic conditions and processes in the storage zone of the 2004–2006 mount st. helens dacite.– in: sherrod, d.r., scott, w.e., stauffer, p.h. (eds.): a volcano rekindled: the renewed eruption of mount st. helens, 2004–2006, usgs professional paper, 1750, 703–725. săndulescu, m (1984): geotectonica româniei [geotectonics of romania – in romanian].– editura tehnică, bucureşti, 336 p. schmidt, m.w. (1992): amphibole composition in tonalite as a function of pressure: an experimental calibration of the al-in-hornblende barometer.– contribution to mineralogy and petrology, 110, 304–310. schmidt, m.w. (1993): phase relations and compositions in tonalite as a function of pressure: an experimental study at 650°c.– american journal of science, 293, 1011–1060. stein, e. & dietl, c. (2001): hornblende thermobarometry of granitoids from the central odenwald (germany) and their implications for the geotectonic development of the odenwald.– mineralogy and petrology, 72, 185–207. geologia croatica 68/1geologia croatica 66 streckeisen, a. (1938): das nephelinsyenit-massiv von ditro in rumänien als beispiel einer kombinierten differentation und assimilation. erh.– verhandlungen der schweizerischen naturforschenden gesellschaft, 159–161. streckeisen, a. (1952): das nephelinsyenit-massiv von ditro (siebenbürgen), i. teil.– schweizerische mineralogische und petrographische mitteilungen, 32, 251–308. streckeisen, a. (1954): das nephelinsyenit-massiv von ditro (siebenbürgen), ii. teil.– schweizerische mineralogische und petrographische mitteilungen, 34, 336–409. streckeisen, a. & hunziker, j.c. (1974): on the origin of the nephelinsyenit massif of ditró (transylvania, romania).– schweizerische mineralogische und petrographische mitteilungen, 54, 59–77. sun, s. & mcdonough, w.f. (1989): chemical and isotopic systematics of ocean basalts implications for mantle composition and process.– in: saunders, a.d. & norry, m.j. (eds.): magmatism in the ocean basins. geological society special publication, 42, 313–346. thomas, w.m. & ernst, w.g. (1990): the aluminium content of hornblende in calc-alkaline granitic rocks: a mineralogic barometer calibrated experimentally to 12 kbar.– in: spencer, r.j., chou, i.m. (eds.): fluid-mineral interactions: a tribute to hp eugster. the geochemical society special publication, 2, 59–63. tischendorf, g. & palchen, w. (1985): zur klassifikation von granitoiden.– zeitschrift für geologische wissenschaften, 13, 615–627. vyhnal, c.r. & mcsween, h.y. jr. (1990): constraints on alleghanian vertical displacements in the southern appalachian piedmont, based on aluminum-in-hornblende barometry.– geology, 18, 938–941. whalen, j.b., currie, k.l. & chappell, b.w. (1987): a-type granites: geochemical characteristics, discrimination and petrogenesis.– contributions to mineralogy and petrology, 95, 407–419. white, a.j.r. & chappell, b.w. (1983): granitoid types and their distribution in the lachlan fold belt, southeastern australia.– in: roddick, j.a. (ed.): circum-pacific plutonic terranes. geological society of america memoirs, 159, 21–34. wright, j.b. (1969): a simple alkalinity ratio and its applications to questions of non-orogenic granitic-gneisses.– geological magazin, 46, 1097–1111. wu, f.y., sun, d.y., li, h., jahn, b.m. & wilde, s. (2002): a-type granites in northeastern china: age and geochemical constraints on their petrogenesis.– chemical geology, 187, 143–173. zhang, s.h., y. zhao & song, b. (2006): hornblende thermobarometry of the carboniferous granitoids from the inner mongolia paleo-uplift: implications for the tectonic evolution of the northern margin of north china block.– mineralogy and petrology, 87/1–2, 123–141. manuscript received october 11, 2014 revised manuscript accepted january 12, 2015 available online february 27, 2015  abstract the basement of the pannonian basin contains several fractured metamorphic hydrocarbon reservoirs that typically form structural highs between the neogene sedimentary sub-basins. one of the largest reservoirs, the szeghalom dome, is located on the northern margin of the békés basin and is mainly composed of variscan gneisses and amphibolites with different metamorphic evolutions. these petrologically incompatible blocks were juxtaposed by post-metamorphic tectonic activity that was accompanied by the formation of brittle fault zones with higher transmissibilities. the aim of this study was to define the spatial arrangement of these fault zones and their internal architecture by integrated evaluations of borehole core and well-log data from a group of wells in the central part of the field. spatial correlations between the reconstructed 1d lithologic columns revealed the main structural elements of the szeghalom dome. the low-angle (<15°) thrust faults most likely developed due to north-northwest vergent cretaceous nappe tectonics, which were probably responsible for the juxtaposition of the different metamorphic blocks. a complex system of normal faults throughout the basement high provides evidence of intense miocene extensional tectonic activity. this phase of the geodynamic evolution of the basin is believed to be responsible for the horst-graben structure of the szeghalom dome. the integration of the structural results with datasets of the palaeo-fluid evolution, recent production and fracture network geometry, indicates the importance of these fault zones in both the migration of hydrocarbons from the adjacent sub-basins to the overlying sediments and the development of significant storage capacity within the strongly fractured rock masses, (mainly the amphibolite bodies). these observations of fluid flow also emphasized the impact of strong anisotropic permeability anisotropy of the faults throughout the fractured reservoir. keywords: fractured reservoir, variscan basement, fault zones, well-log interpretation, fault rock analysis 1. introduction brittle fault zones have a key role in the hydrodynamics of fractured reservoirs (nelson, 2001). they can behave as barriers, conduits or as a combination of both (caine et al., 1996), so understanding their internal structure is crucial. previous studies (caine et al., 1996; evans et al., 1997; molnár et al., 2014) on the make-up of fault zones defined two main structural elements: 1) the weakly disaggregated, densely fractured “damage zone”, which is generally associated with higher conductivity and permeability relative to the undeformed protolith; and 2) the intensively destructural controls on petroleum migration and entrapment within the faulted basement blocks of the szeghalom dome (pannonian basin, se hungary)  molnár, lászló, m. tóth, tivadar and schubert, félix department of mineralogy, geochemistry and petrology, university of szeged, egyetem u. 2., h-6722, szeged, hungary (molnar.laszlo@geo.u-szeged.hu) doi: 10.4154/gc.2015.19 geologia croaticageologia croatica geologia croatica 68/3 247–259 11 figs. 1 tab. zagreb 2015 geologia croatica 68/3geologia croatica 248 2. geological setting due to its complex multistage tectonic history, the pannonian basin is a complicated mosaic of structural blocks with different patterns of geological evolution. the crystalline basement of the pb is mainly composed of variscan metamorphic rocks with significantly different pressure-temperature-time histories (szederkényi et al., 1991). the szd is one of the best known units and has a heterogeneous lithological composition (m. tóth, 2008; fig. 1). the northern part of the szd and the neighbouring areas are mainly composed of orthogneiss that is derived from the medium-grade metamorphism of an igneous intrusion. in some borehole cores, undeformed microgranite dykes have no textural indications of metamorphism. these lithologies are jointly called the og group. in the central and southern parts of the szd, two other types of gneiss are dominant. the sg group is composed of high metamorphic grade sillimanite and garnet-bearing biotite gneiss that is often coupled with garnet-bearing amphibolite. in contrast, amphibolite and amphibole-biotite gneiss (ag group) with medium grade metamorphism is common at the uppermost structural level. these metamorphic blocks with distinct evolutions (m. tóth, 2008) were juxtaposed as a result of post-variscan structural movement. the most significant tectonic event after the variscan metamorphism was the eoalpine compressional tectonic phase (austrian, laramian time sequences), which formed complicated nappe systems throughout the basement of the pannonian basin. several studies have demonstrated the existence of nappe tectonics in the pb (posgay et al., 1995; tari et al., 1999), which resulted in the widespread formation of subhorizontal, north-northwest-directed thrusts throughout the basement. later back-arc type extension during the middle miocene resulted in the formation of metamorphic core complexes coinciding with the exhumation of a series of crystalline domes along low-angle normal faults (horváth et al., 2006). these structures were further complicated by sinistral strike-slip fault zones with significant horizontal displacements (albu & pápa, 1992). during the badenian, the intense extension formed horst-graben structures along north-south striking normal faults (m. tóth, 2008). as a result of the complex post-metamorphic evolution of the szd, a dense fracture network with significant fluid storage capacity developed (m. tóth, 2008). previous analyses of the fracture network (m. tóth et al., 2004) and fracture-filling mineral assemblages (juhász et al., 2002) demonstrated the significant difference in rheological behaviours of the amphibolite and gneiss bodies. this difference led to the development of a fracture network that is above the percolation threshold of the amphibolites; in contrast, the fracture network in the gneisses is usually below this limit and contains unconnected fracture systems (m. tóth et al., 2004). the higher storage capacity of amphibolites compared to the gneisses is also demonstrated by palaeo-fluid reconstructions of the szd (schubert, 2003; schubert et al., 2007), which reported hydrocarbon-bearing fluid incluformed and fragmented fault core, where the pre-existing rock fabrics have been destroyed by the development of the fault and have been replaced by fault rocks. several studies have revealed that the formation of the fault core is often coupled with a significant decrease in permeability (evans et al., 1997; wibberley & shimamoto, 2003; storti et al., 2007), which is mainly a result of cataclasis, clay smearing or clay gouge formation and cementation (moeller-pedersen & koestler, 1997; manzocchi et al., 2010). the geometry of the juxtaposed lithologies and their relative transmissibility are also important factors in the conduit/barrier behaviour of fault zones (allan, 1989). the hydraulic character of the deformed zones is further complicated by their strong anisotropic permeability (evans et al., 1997). the highest permeability evolves parallel to the fault plane and the slip vector. in contrast, the hydraulic conductivity is one to four orders of magnitude lower parallel to the fault plane and perpendicular to the slip vector. similar characteristics can be observed perpendicular to the fault plane and the slip vector. these can result in many types of hydraulic behaviour of faults depending on the widths of distinct structural elements (damage zone and the fault core) with respect to the total width of the fault zone: localized conduits, localized barriers, distributed conduits or combined conduits-barriers (caine et al., 1996). the large-scale spatial interpretation of fault zones in hydrodynamic systems can be problematic, especially with a lack of borehole cores, packer measurements or sophisticated modeling because the main structural elements are often below the limit of seismic resolution (ben-zion & sammis, 2003). this phenomenon increases the value of data available from cores and well-logs and suggests the importance of their integration and calibration. this study focuses on the pannonian basin (pb), which is part of the alpine-carpathian-dinaric orogenic belt. due to its complex mesozoic-neogene evolution (e.g., tari et al., 1992; csontos & nagymarosy, 1998), the southeastern part of the pb consists of deep sub-basins that are separated by metamorphic basement highs (e.g., tari et al., 1999; m. tóth et al., 2009). in many cases, these blocks act as fractured water and hydrocarbon (hc) reservoirs in which the brittle fault zones play an important role in fluid storage and migration. one of the best known basement highs is the szeghalom dome (szd), which is also one of the largest fractured basement hc reservoirs in the pb (nelson, 2001). according to unpublished industrial reports however, only a small portion of the accumulated hydrocarbons has been produced because of the complex structural and lithological architecture of the szd. here, we attempt to reconstruct the structural evolution of the study area and determine the role of the internal architecture of the fault zones in the local fluid flow regimes. moreover, correlation of the palaeo-fluid evolution with the recent hydraulic features of the szd was another aim of this work. in the recent case, well-test results and earlier fluid inclusion data were available to estimate both the past and current hydraulic characteristics of the analyzed fault zones. molnar et al.: structural controls on petroleum migration and entrapment within the faulted basement blocks of the szeghalom dome geologia croatica 249 sions exclusively from the amphibolite bodies and the dama ge zone of the faults. the wide fault zones that separate blocks of different metamorphic evolution patterns within the szd may have a key role in the communication between the crystalline basement and the neighboring sedimentary basins; because the flanks of the szd are surrounded by relatively deep sedimentary sub-basins with significant overpressures, the fractured basement can act as a migration pathway from the juxtaposed sediments to the overlying sediments (vass et al., 2009). these brittle fault structures can also link separated amphibolite bodies (m. tóth, 2008; vass et al., 2009). based on sedimentological and organic-geochemical evidence, the main sources of the hydrocarbons that are currently produced from the szeghalom dome basement reservoir are believed to be the middle to upper miocene shales (teleki et al., 1994). following the badenian exhumation, the szd formed an island in the late miocene pannonian lake. the basal conglomerate (békés formation) covered the coastal zones of the basement, while the local basinal clay marl aquitard (endrőd formation) either overlaid the conglomerate or rested directly on the metamorphic domes. this marl grades upwards into a thick succession of turbiditerich (szolnok formation) and slope (algyő formation) sediments, which are thinner but coarser grained above the basement highs (mátyás, 1994) and represent a possible pathway for vertical migration (juhász et al., 2002). during the “post-rift” phase of the basin evolution, the exposed metamorphic highs subsided (“thermal subsidence”; horváth et al., 1988; m. tóth, 2008) to a depth of approximately 3 kilometres and provided pathways for fluid migration and/or storage (juhász et al., 2002). according to teleki et al., 1994, the recently produced hydrocarbons of the szd most likely generated in the adjacent overpressured sub-basins located south of the szd, such as the békés basin and the vésztő graben (fig. 1). 3. samples the study area is located north of the highest part of the szd (fig.1/c), where the top of the basement is composed of rocks of the ag group. sg group rocks are located in the deeper parts of the basement and are separated from the ag group rocks by wide brittle fault zones. the borehole cores used for the petrographic analysis are from wells a-11, -20, -22, -180: the depth intervals of the samples are summarized in table 1. the most important well (a-180) is located north of the central, highest part of the szd and intersects a major fault zone. core recovery from the fault zone is nearly 100%. the fault zone separates the lithologic units of the ag group in the hanging wall and the sg group in the footwall. the examined section is approximately 20 metres wide and extends from a depth of 1913 metres to 1936 metres; it is primarily composed of britfigure 1: a) location of the szeghalom dome in the pannonian basin and its geological environment. b) szeghalom dome in the eastern part of the pannonian basin with the adjacent sub-basins and elevated basement highs. c) locations of the sampled wells in the central part of the szd. the contour map indicates the depth to the basement in metres. geologia croatica 68/3geologia croatica 250 tle fault rocks with different degrees of deformation (fig. 2). the cores were not oriented, so their proper structural interpretation was not available. nevertheless, the thin sections were made parallel with the lineations and perpendicular to the foliations, where it was possible. samples of both the undeformed footwall and the hanging wall were analyzed to define their well-log properties. well-log analysis was applied to the wells a-11, -20, -22, -36, -177, -178 and -180. the well-log data were provided by the mol hungarian oil and gas company. the well-log measurements were recorded every 20 cm for the following parameters: spontaneous potential (sp), caliper width (cal), resistivity (res), density (den), compensated neutron porosity (cn), acoustic velocity (ac) and natural gamma logs (gr). 4. methods the available borehole cores were analyzed petrographically at both mesoand micro-scales. the tectonites were classified according to their clast geometric parameters as described in molnár et al. (2014). the well-log data were calibrated on the depth intervals that overlapped with the petrographically analyzed cores. the data set was statistically evaluated using the ibm spss 20.0 statistics software. the discriminant function analysis method was used to separate the lithologic groups based on their well-log properties (the forward stepwise method using wilks’ lambda) (fig. 3/a). first, a discriminant function was computed to define the difference between the undeformed wall rock (ag and sg together) and the tectonized depth intervals by calculating the proper linear combination of the measured well-log data (fig. 3/b). discriminant functions were then calculated to define the different types of fault rocks (fault breccia, cataclasite, fault gouge) within the zones that were classified as tectonized in the previous step (fig. 3/b). both types of discriminant functions were cross-validated to test the efficiency of the prediction model. the computed functions were then applied to the depth intervals of the analyzed wells where the lithology was unknown. 5. results 5.1. petrography the internal structure of the shear zone in well a-180 reflects the diversity of the petrographic characteristics of the different types of tectonites (fault breccias, cataclasites and fault gouges) (fig. 2). samples from a-11, a-20 and a-22 composed of strongly fractured and partly brecciated gneisses from the ag lithologic group. intact borehole core from the sg group was available only from one well (a-11: 20072009 m) with sillimanite-bearing biotite gneissic composition. most of the analyzed samples in a-180 were composed of coarse fault breccia that contained weakly disaggregated structures and clast sizes that were typically greater than the cm-scale (fig. 2/a-b). the particles in these samples are only weakly rotated and often fit together along their sharp, angular dilatational edges, reflecting a typical jigsaw puzzle texture (mort & woodcock, 2006). these weakly disaggregated fault breccia particles usually have a chaotic structure and lack a clast shape preferred orientation. the particles are dominantly composed of rock fragments that are derived from the wall rock and have a recognizable gneiss precursor, while single mineral fragments are subordinate in the fault breccias. a few samples of the breccias have similar internal structures; those with smaller clasts are regarded as micro-breccias, and the coarse fault breccias are often embedded in greenish chlorite or brownish iron-oxide (hematite) cement. precipitation of fe phases is always visible on the margins of the angular clasts. several samples show characteristic features of cataclastic deformation that resulted in a decrease in clast size and an increase in the matrix ratio, while the preferred local orientation of the clasts is defined by their long axes (fig. 2/cd). the fractured grains are often accompanied by deformed phyllosilicate flakes, which implies locally brittle-ductile transitional deformation. the fragmentation in the cataclasite samples makes the protolith of the crushed particles difficult to define because they are often monomineralic (composed mainly of quartz or feldspar). iron-oxide cement is also often present, in contrast to the missing chlorite cement. a third type of samples, the incohesive fault gouges, is present in thin deformational bands (fig. 2/e-f). these bands are mainly composed of strongly comminuted mono-crystalline (mainly quartz) particles; only a few survivor rock fragments are observable. the isolated fragments are surrounded by the completely crushed parts of the protolith and the fabric of these samples also indicates a semi-brittle style deformation. these fault gouge zones are usually a few cm wide and presumably define the localized slip zones of the faults, which are probably the locations of the most intensive displacements. the kinematics of the observed slip surfaces and their structural interpretation were not possible to determine in the lack of oriented cores. nevertheless, in the micro-scale evaluations the reverse micro-faults and the manners of the compressional activity were predominant. the fault zone in well a-180 is mainly composed of weakly disaggregated, coarse fault breccias: the detailed lithologic composition of the interval is visible in figure 3/a. despite their fragmented texture, the fault breccia core samples reflect a hardened and mechanically intact structure (fig. 4/a-b). the cohesiveness of the samples was most likely retained due to the pervasive multistage cementation along the table 1: the available borehole cores with their intervals, in metres below sea level. well number depth intervals of the borecores (meters below sea level) a-11 1957–1968 2007–2009 a-20 1901–1903 1976–1979 a-22 2117–2119 a-180 1913–1936 molnar et al.: structural controls on petroleum migration and entrapment within the faulted basement blocks of the szeghalom dome geologia croatica 251 fault zone, which was also described by earlier works (juhász et al., 2002, schubert et al., 2007): these cement minerals are mainly chlorite, calcite, hematite and partly quartz. although the fault breccias have a hardened structure, often cm-scale open pore space could be preserved in these cores, which likely maintain the higher permeability of the samples. this intensely fractured host rock presumably forms the damage zone of the fault zone. in contrast, the zones of cataclasite and fault gouge are up to one meter wide and are considered as the fault cores; they are most clear at three distinct depth intervals (1917, 1922 and 1926 metres below sea level) (fig. 3/a). these samples dominantly have an incohesive structure: cores can be broken into components with fingers (fig. 4/c-d) and a weak drop was also observed figure 2: thin sections in the fault zones. a, b) coarse fault breccia with gneissic rock fragments (1n, +n) (well a-180). c, d) oriented, elongated clasts in cataclastic fabric (1n, +n) (well a-180). e, f) layers of comminuted gouge containing primarily crushed mono-crystals (1n, +n) (well a-180). the scale bars are 500 µm long. geologia croatica 68/3geologia croatica 252 in the core recovery ratio of these intervals (by unpublished industrial reports). increasing deformation is thus usually coupled with the significant weakening of the fault core. the cataclasite and fault gouge surfaces are structurally confined between horizons of coarse fault breccia. as in previous studies (e.g., evans et al., 1997), the fault cores are typically one meter thick; the fault cores imply the localization of strain within the fault zone and mark the locations of largest displacement. 5.2. well-log data to extend the lithologic data from the cores to the other intervals of wells, calibration with well-log data was necessary. the proper combination of well-log data was calculated by applying discriminant functions analysis to separate the distinct lithologies (fig.3/b). the undeformed host rock (fig. 3/c) and the tectonized samples (fig. 3/d) were separated using the following discriminant function: d(1-2) = 1.1 * natural gamma (gr) – 0.5 * resistivity (res) – 0.9 * density (den) the calculated function successfully discriminated the undeformed host rock and the tectonized intervals without any overlap (fig 5/a). to define the internal structure of the tectonized zones, the lithologically-known fault rocks (fault figure 3: details of the log-to-core calibration. a) lithological composition of the fault zone in well a-180 with the calculated d(1-2),(3) and (4) values. the fault gouge-bearing intervals at 1917, 1922 and 1926 metres indicate the locations of the largest displacements. b) theoretical workflow for the determination of the lithologic architecture in the analyzed wells. functions d(3) and d(4) are applied only when d(1-2) defines the sample as a tectonite. c,d) representative well-log sections for undeformed (c) and deformed (d) depth intervals, which are verified with core data. figure 4: characteristic core samples from the fault zone of a-180. a,b) cohesive, coarse grained fault breccia core. the structure of the sample is intact, despite the pervasive brittle deformation and fragmentation. c,d) incohesive fault rock samples from the presumed fault core of the shear zone. the most intense deformation is accompanied with the mechanical weakening of the tectonites. molnar et al.: structural controls on petroleum migration and entrapment within the faulted basement blocks of the szeghalom dome geologia croatica 253 breccia, cataclasite and fault gouge) were then separated using two discriminant functions: d3 = 0.7 * compensated neutron porosity (cn) – 0.5 * resistivity (res) d4 = 0.6 * density (den) – 0.9 * natural gamma (gr) these two discriminant functions clearly separated the different fault rocks, especially the clay-rich fault gouge samples (fig. 5/b). these functions were then applied to classify the lithologically-unknown depth intervals of wells a-11, -20, -22, -36, -177, -178 and -180 to determine their lithologic and structural compositions. 6. spatial extension of petrological and well-log data 6.1. well-log properties of the lithologies the weights of the parameters in discriminant function d(12) define the main geophysical differences between the undeformed protolith and the tectonized zones (fig. 5/a). the greatest factor in the difference is the high natural gamma ray values, which implies a raised amount of clay minerals that is presumably caused by the intensely weathered and altered host rock in the fault zone (fig. 6). the relatively lower electrical resistivity of the tectonites reflects their strongly fractured/fragmented characteristics, which results figure 5: a) separation of the deformed and undeformed depth intervals using the scores of the calculated d(1-2) function. the most important well-log parameters used to discriminate the intervals were the natural gamma, density and resistivity values. b) discrimination of different fault rock types with the calculated d3 – d4 functions, which are mainly based on the compensated neutron porosity, resistivity, density and natural gamma log values. figure 6: spatial variations of the most important well-log parameters for an idealized fault zone. the darker colours indicate greater parameter values. according to this interpretation, the deformation is often associated with decreasing density and resistivity towards the core zone. the most significant porosity enhancement develops in the weaker fragmented and brecciated zones. res: resistivity, den: density, cn: compensated neutron porosity gr: natural gamma. geologia croatica 68/3geologia croatica 254 in stronger fluid infiltration into these zones. the lower densities are probably related to the presence of the higher fracture density in the tectonized zones, which is often coupled with porosity enhancement (fig. 6). the petrographic and well-log properties of the diverse tectonite types are distinctly different (fig. 5/b), which reflect the internal structure of the fault zones. according to function d3, higher levels of deformation are manifested in increases of the compensated neutron porosity values and further decreases of the electric resistivity. in function d4, higher density and lower gamma-ray values are characteristic. these suggest that the intensely deformed parts of the fault zones (cataclasites and fault gouges) can be characteri zed by low densities and resistivities and that further elevated natural gamma activity and compensated neutron porosity values mark the fault core, which is consistent with the observations of hung et al. (2007) and jeppson et al. (2010). the density and resistivity logs imply intensive fracturing, fragmentation and comminution, while the natural gamma and neutron porosity values indicate strong weathe ring and clay mineral formation with significant porosity reduction (fig. 6). in contrast, the interpreted damage zone with coarse fault breccias has higher density and resistivity values and lower gamma and neutron porosity values (fig. 6). these suggest that the weaker disaggregated zones can maintain a significantly higher porosity than the comminuted fault core. 6.2. structural interpretation of the analyzed part of the szd the application of the discriminant functions described above to the well-log data from wells a-11, -20, -22, -36, -177, -178, and -180 provided an opportunity to determine the lithologies that were present in these wells and to understand the structural evolution of the szd (fig. 7). based on the available data, three groups of wells can be distinguished from the seven wells: two triplets (a-180, -11, -20 and a-36, -177, -178) and a block containing one well (a-22). the most important well was a-180 because the large number of core samples provided useful information about the architecture of the szd. the fault zone in well a-180 contains strong structural heterogeneities between the depths of ~1915 and 1935 metres, where the three main cataclasite and fault gouge-bearing zones are always embedded in coarse fault breccia members (fig 3/a). these comminuted planes – especially the clay-rich gouge zones – can act as the slip zones of the fault zones, and their presence indicates strain localization. an interpretation of the well-log from well a-20, (which is the closest well to a-180), indicates that it also contains a distributed fault zone with wide, gougebearing fault core between ~1990 and 2005 metres (fig. 7). although no core was collected across this interval, the welllog data indicate that the two wide tectonized intervals in the figure 7: the interpreted lithological compositions of the analyzed wells. the dashed line indicates the observed low-angle fault surfaces. the wells form two triplets, including a northern and a southern block. along with the lithological composition, the calculated d(1-2) values are also illustrated along the 1d section of the wells. molnar et al.: structural controls on petroleum migration and entrapment within the faulted basement blocks of the szeghalom dome geologia croatica 255 neighbouring wells are parts of the same fault zone. similar gouge-bearing, distributed fault zones with wide damage zones are present in well a-11 at approximately the same depth interval (≈1985–2000 m) as in a-20 (fig. 7). these three occurrences of the interpreted shear zone define a low angle (13°) fault plane that dips to the southeast. other more weakly fragmented and thinner fault planes are also observed in these wells but do not contain cataclasite gouge-bearing (slip) zones. these data suggest that the fault cores were the locations of the largest displacements and can be considered a major fault zone (fig. 7). wide tectonized zones that indicate relatively large displacements are present in well a-178 at depths of ≈19251945 metres. similar zones are also present at similar depths in wells a-177 and a-36; however, the interval is slightly thinner in a-36 (a-177: ≈1955-1970 m, a-36: ≈1960-1980) (fig. 7). these depth intervals also include the gouge-bearing slip zones, which imply that these intervals have a similar origin to the shear zone in wells a-11, -20, and -180. in this sense, the fault zone in the southern group of wells (a-36, -177, and -178) is the continuation of the zone found in the northern group with a slightly smaller dip angle (8°) but a similar south-southeast dip. although the small amount of available information only allows a rough estimate of the geometry of the fault planes, and there is a slight difference in the dip angles and directions, the faults in these groups of wells were likely affected by a similar deformational event. based on the interpretation of several analogous examples from the crystalline basement (e.g., pap, 1990; tari et al., 1999), these fault zones can be interpreted as a low-angle thrust with a northwest vergence. this explanation is consistent with the reinterpretation of 2d seismic profiles from the metamorphic basement (m. tóth et al., 2009). because these old seismic surveys mainly focused on the overlying clastic sediments, they provided only sporadic reflectors from the crystalline basement. using sophisticated seismic interpretation techniques, m. tóth et al. (2009) defined the largest structural elements and characterized most of them as low-angle thrust surfaces. earlier studies reported that the formation of these low angle (≈5-15°), northwest-vergent thrust sequences throughout the basement of the pannonian basin are related to eoalpine compressional activity during the late cretaceous nappe formation (teleki et al., 1994; tari et al., 1999, kovács et al., 2000). the ag and sg lithologic groups, with their distinct metamorphic pathways, were juxtaposed by this eoalpine nappe activity. this event is presumably also responsible for the formation of fault zones on the sgog contact, according to the results of unpublished industrial reports. the repeated presence of the thrust surfaces and their spatial arrangement indicate post-cretaceous tectonic activi ty between the northern and the southern groups of wells, which cross-cut the initially approximately uniform thrust surface (figs. 7 and 8). the dip of the thrust and the depth of the tectonized intervals indicate high angle extension with approximately 150 metres of vertical displacement combined with tilting of the northern hanging wall block (fig. 9). a similar tectonic style is indicated in well a-22, which reached the basement surface approximately 200 metres deeper than in the adjacent wells and penetrated only ~20 metres of basement rocks of the ag group (fig. 7). because the ag group is in the highest structural locations in the szd (m. tóth, 2008) (fig. 8) and always forms the top of the basement, the significant vertical difference between wells a-22 and a-180 is probably also the result of post-cretaceous motion (fig. 9). extensional tectonic activity has been widely reported in the szd and can be related to the formation of horst/graben structures during the syn-rift stage of the opening of the pannonian basin during the miocene (m. tóth, 2008). as a result of the complex evolution of the pb, this type of structure is most common in the central part of the basin; in contrast, the degree of extension at the basin margins was high enough to form metamorphic core complexes (horváth et al., 2006). this phase of basin evolution culminated in the uplift and the exhumation of the szd from a relatively shallow depth (<10 km) and the subsidence of nearby sub-basins (e.g., békés basin) (teleki et al., 1994; m. tóth, 2008). figure 8: basement map of the szeghalom high with the major interpreted structural elements. the contour map indicates depth to the basement in metres. the cretaceous nappe structures were overprinted by complex neogene normal faulting. note that members of the ag group dominate at the top of the basement. for details of transect a-a’, see figure 9. geologia croatica 68/3geologia croatica 256 6.3. discussion of palaeo-fluid regimes in the analyzed part of the szd in this section, the new structural data are integrated with the results of previous studies, particularly with respect to the hydrodynamic characteristics of the szd (fig. 9). m. tóth et al. (2004) found that the densely fractured amphibolite bodies in the ag group contain significant storage capacity in the metamorphic blocks of the szd. the previously reconstructed palaeo-fluid evolution was based on analyses of aqueous and petroleum inclusions in the fracture-filling quartz crystals, primarily from the amphibolites and subordinately from the damage zones of faults (schubert, 2003; schubert et al., 2007). the fact that most of the analyzed fluid inclusions are present in the amphibolite zones, while they are totally absent from the gneisses, strengthens the interpretation that the main storage capacity is related to the intensely fractured amphibolite bo dies. in this model, the damage zones of brittle faults served as migration pathways towards the amphibolites, the higher porosity of which was deduced from petrographic observations (coarse angular clasts with preserved pore space; c.f. fig. 2). the geochemical features and the degree of maturation indicate that the petroleum fluids from wells a-180 and a-20 have similar characteristics, in contrast to well a-11, which contains significantly different (less mature and/or more intensely degraded) hydrocarbon fluids trapped in petroleum inclusions. no fluid inclusion data are available from wells a-22, -36, -177, and -178. the fluid inclusion data suggest that the rocks encountered in wells a-20 and a-180 form a connected palaeo-hydrodynamic regime, while the rocks in well a-11 represent a separate fluid system, at least during the cementation of quartz in the fractures (fig. 9). these data clearly indicate that even though these three wells are close to each other and are aligned along the same wide brittle shear zone (see fig. 9), the rocks represent separate hydrodynamic regimes. several scenarios can explain the hydraulic compartmentalization of the szd. an unlikely but possible scenario is related to the significant temporal/spatial variability in the density and porosity/permeability of the fracture network, which is probably caused by the multistage cementation and reopening of fractures (juhász et al., 2002). in this scenario, the petroleum inclusions represent the stage of the evolution of the fracture network that was locally favourable for fluid inflow (after fracture opening/reopening), which was followed by cementation, fracture sealing and fluid inclusion entrapment. however, the spatial distribution of the open fractures at a particular time – and thus the favourable conditions for fluid inflow – was heterogeneous across the fracture network. this probably resulted in the local absence of entrapped hydrocarbon inclusions at a certain degree of maturity during the process of migration within the basement. as a result, this model implies the formation of temporarily separated hydraulic regimes, which provides a possible mechanism for the isolated fluid systems of the szd. however, the absence of pervasive fracture propagation in diverse stress fields does not favour this theory. figure 9: west-northwest – east-southeast cross section of the szeghalom dome. the dashed lines indicate the separate palaeo-fluid systems based on previous fluid inclusion results (schubert et al., 2007). the late cretaceous nappe surfaces were cut by high angle neogene normal faults. significant storage capacity in the basement is exclusively related to amphibolite bodies in the ag group. the composition of the basement is unknown below well a-22. the horizontal components of the cross section are not to scale. molnar et al.: structural controls on petroleum migration and entrapment within the faulted basement blocks of the szeghalom dome geologia croatica 257 the most likely scenario is compartmentalization due to the strong permeability anisotropy of the fault zones, which has been discussed by numerous authors (evans et al., 1997; zhang et al., 2001). permeability anisotropy can be controlled by the shear displacement, effective stress, claysmearing along the fault plane or anisotropic microstructure (géraud et al., 2006). these papers revealed distinct differences in permeability with anisotropy ratios as high as 104 (evans et al., 1997). the highest values are parallel to the fault plane and to the slip direction (k(par1)) (fig. 10). the lowest permeability values are perpendicular to both the fault plane and the slip direction (k(per)), while transitional values were reported parallel to the fault plane and perpendicular to the slip direction (k(par2)). this strong anisotropy can lead to hydraulic separation along the strike of the major fault zone in the szd, as is observed in the different palaeo-fluid characteristics in the neighboring a-11 and a-20 wells. moreover, the maximum permeability along the dip of the fault zone can explain the connected palaeohydraulic system encountered in wells a-20 and a-180 (fig. 9). the palaeo-fluid regimes within the szd could also have been fragmented due to the intense multistage tectonic activity in the neogene (lőrincz, 1996). the interpreted structural architecture of the szd supports this hypothesis. the normal faults probably disturbed the hydrocarbon migration in their vicinity (e.g., a-11, fig. 7) and could have played a key role in the entrapment of the fluid inclusions with diverse chemical features (a-11 vs. a-20 and -180). it is difficult to determine whether these normal faults behaved as sealing faults or provided conduits for hydrocarbon migration towards the overlying clastic sediments. nevertheless, the second hypothesis is supported by the results of juhász et al. (2002) on the hydraulic connection between the basement and the overlying sediments. it is unclear if the palaeo-fluid regime can be correlated with the recent hydrodynamic regimes. according to schubert (2003) and schubert et al. (2007), the palaeo-fluid migration recorded by the hc-bearing fluid inclusions occurred between the cretaceous and the middle miocene (badenian). the onset of migration into the basement has been determined by biological marker compounds in the analyzed hc, the source of which could not have been generated before the cretaceous (schubert, 2003). the data of juhász et al. (2002) and schubert et al. (2007) indicate that the palaeo-fluid migration ended before the badenian exhumation of the szd. in contrast, based on industry data (teleki et al., 1994), the currently produced hydrocarbons of the szd must be originated from the adjacent, deep subbasins, such as the békés basin or the vésztő graben. their source rocks were organic-rich shales with middle to upper miocene ages and must be generated following the subsidence of the sub-basins (fig. 11). these data suggest some dissimilarity between the palaeoand the recent petroleum systems based on the possible source rocks. nevertheless, the results of the well-test data indicate several similarities between the palaeoand recent fluid systems. in wells a-11 and a-36, the brecciated and intensely fractured damage zones of the thrust faults and the fracture system of the ag group have produced a significant amount of hydrocarbons (fig. 7). deeper water-producing intervals in a-180, a-20 and a-11 are also related to these permeable units but are below the oil-water contact. however, a welltest of well a-11 from the sg group did not show any inflow of fluid, indicating the impermeable nature of this lithological unit. this implies that the same structural elements participated both in the past and current migration and entrapment processes. because of the limited width and spatial distribution of the low-angle thrust faults, these zones of elevated transmissibility can only act as migration pathways within the reservoir. in contrast, the extensive amphibolite blocks of the ag group in the hanging wall presumably form the main reservoir rock of the basement petroleum system. according to the model for the mechanism of the recent flow systems of vass et al. (2009), the szd has a very strong hydraulic connection with the overlying and juxtaposed sediments because the elevated blocks of metamorphic basement can drain the adjacent overpressured basins below the local aquitard (endrőd formation) and have an important role in the compensation of their pressure conditions (fig. 11). due to its dense fracture network and numerous wide fault zones, the szd behaves as a migration pathway towards the overlying clastic sediments (szolnok and algyő formations); the relatively thin but rapid and notable fluid flux may have resulted in a so-called “chimney effect” in the internal parts of figure 10: the permeability architecture of a thrust fault zone according to evans et al. (1997). the highest permeability values occur parallel to the fault plane and parallel to the slip direction (k(par1)), and the lowest permeability values occur perpendicular to both the fault plane and the slip direction (k(per)). transitional permeability values occur parallel to the fault plane and perpendicular to the slip direction (k(par2)). these results indicate that the fault zone has a significant (104) anisotropic permeability ratio. geologia croatica 68/3geologia croatica 258 the crystalline rock body (vass et al., 2009). the evaluation of the diagenetic history (juhász et al., 2002) also demonstrated that the basement rocks and the overlying sediments must have been hydraulically connected since the middle miocene. this evidence underlines the importance of the intensely fractured parts of the ag group and the dama ge zones of the major fault zones in both the palaeo(based on fluid inclusion data) and recent (based on production data and modeling) hydrogeological systems of the szd despite the differences that were caused by the complex neogene evolution of the szd (juhász et al., 2002; m. tóth, 2008). 7. conclusions (1) in this study, we identified the master fault zones of the szeghalom dome, which is one of the largest fractured basement hydrocarbon reservoirs in the pannonian basin. according to previous investigations, these wide fault zones are mainly related to post-metamorphic tectonic events and possibly act as migration pathways because of their higher porosity and permeability. (2) based on integrated evaluations of core and well-log data, 1d lithostratigraphic columns of wells were defined and correlated spatially. the tectonized intervals were distinguished from the undeformed wallrock, and their internal lithological structures (fault breccias, cataclasites, fault gouges) were defined to determine the significant components of these zones (damage zone versus fault core). we characterized the master faults as intervals consisting of extensive fault gouge zones. (3) the spatial arrangement of the fault zones indicates the presence of low angle thrust faults; based on the evolution of the pannonian basin, these faults were interpreted as indications of cretaceous nappe activity. the structure of the szeghalom dome was further complicated by middle miocene extension, which formed blocks in a horstgraben geometry and culminated in the exhumation of the metamorphic high. (4) the data on the structural evolution of the szeghalom basement high were integrated with the results of previous investigations on the fracture network geometry, palaeo-fluid evolution and recent production data. the results suggest that the amphibolite bodies have the highest storage capacity in the basement reservoir; the amphibolites are located exclusively within the ag lithologic group in the structurally highest basement locations. (5) the strong chemical dissimilarities of the hydrocarbonbearing fluid inclusions that are trapped in fracture-filling quartz veins can be explained by several theories but probably developed due to the significant permeability anisotropy in the fault zones that was derived from their complex architecture coupled with the effect of the neogene structural evolution on the local flow systems. (6) a comparison of the palaeoand recent petroleum systems of the szeghalom dome revealed that the main difference was caused by the different source rocks of the hydrocarbons. the fault zones played a key role in the migration of the hydrocarbons from adjacent overpressured sub-basins to both the amphibolite bodies and, since at least the middle miocene, to the overlying clastic sediments. figure 11: schematic model of the geodynamic and hydrodynamic evolution of the szeghalom dome. 1: coastal conglomerate (békés formation), 2: basal clay marl, which forms a local aquitard (endrőd formation), 3: turbidite-rich sediments (szolnok formation), 4: delta slope sediments (algyő formation), 5: main brittle fault zones, 6: regional fluid flow system. a) simplified cross section of the variscan multistage metamorphism of the lithological groups at diverse pressure and temperature conditions. b) late cretaceous nappe tectonics along low-angle thrust faults, which juxtaposed the ag, sg and og lithological groups. deformation took place at shallow depths and with unknown overlying rocks. c) middle miocene (badenian) exhumation of the szd with the formation of a series of highangle normal faults and the deposition of pannonian clastic sediments. d) recent hydraulic system of the szd following late miocene subsidence of the area with significant overpressure under the local aquitard (endrőd formation) and the evolution of the “chimney structure”. the cross sections are not to scale. molnar et al.: structural controls on petroleum migration and entrapment within the faulted basement blocks of the szeghalom dome geologia croatica 259 acknowledgement we thank mol hungarian oil and gas company for providing the samples, datasets and the financial support of this research. balázs kiss (mol) is thanked for the fruitful discussions about the behaviour of the szeghalom reservoir. reviews by istván bérczi and gyula maros have significantly improved the manuscript, and are much appreciated. english was corrected by american journal experts. references albu, i. & pápa, a. (1992): application of high-resolution seismics in studying reservoir characteristics of hydrocarbon deposits in hungary.– geophysics, 57, 1068-1088. allan, u.s. (1989): model for hydrocarbon migration and entrapment within faulted structures.– aapg bulletin, 73, 803-811. ben-zion, y. & sammis, c.g. (2003): characterization of fault zones: pure and applied geophysics, 160, 677–715. caine, j.s., evans, j.p. & forster, c.b. (1996): fault zone architecture and permeability structure.– geology, 24, 1025–1028. csontos, l. & nagymarosy, a. (1998): the mid-hungarian line: a zone of repeated tectonic inversions.– tectonophysics, 297, 51–71. evans, j.p., forster, c.b. & goddard, j.v. (1997): permeabili ty of fault-related rocks and implications for fault-zone hydraulic structure.– journal of structural geology, 19, 1393–1404. géraud, y., diraison, m. & orellana, n. (2006): fault zone geometry of a mature active normal fault: a potential high permeability channel (pirgaki fault, corinth rift, greece).– tectonophysics, 426, 6176. horváth, f., dövényi, p., szalay, á. & royden, l.h. (1988): subsidence, thermal and maturation history of the great hungarian plain.– in: royden, l.h. & horváth, f. (eds.): the pannonian basin: a study in basin evolution.– aapg memoir, 43, 355-372. horváth f., bada g., szafián p., tari g., ádám, a. & cloetingh, s.(2006): formation and deformation of the pannonian basin: constraints from observational data.– in: gee, d.g. & stephenson, r.a. (eds.): european lithosphere dynamics, geological society, london.– memoirs, 32, 191–206. hung, j., wu, y., yeh, e. & wu, j. (2007): subsurface structure, physical properties, and fault zone characteristics in the scientific drill holes of taiwan chelungpu-fault drilling project– terrestrial atmospheric oceanic science, 18, 271-293. jeppson, t.n., bradbury, k.k. & evans, j.p. (2010): geophysical properties within the san andreas fault zone at the san andreas fault observatory at depth and their relationships to rock properties and fault zone structure.– journal of geophysical research, 115, b12423. juhász, a., m tóth, t., ramseyer, k. & matter, a. (2002): connected fluid evolution in fractured crystalline basement and overlying sediments, pannonian basin, se hungary.– chemical geology, 182, 91–120. kovács, s., szederkényi, t., haas, j., buda, gy., császár, g. & nagymarosy, a. (2000): tectonostratigraphic terranes in the preneogene basement of the hungarian part of the pannonian area.– acta geologica hungarica, 43, 225–328. lőrincz, k.d. (1996): determination of stress-field history on the basis of multiphase tectonism identified in the seismic profiles, in the western part of the szolnok flysch belt.– magyar geofizika, 37, 228–246 (in hungarian with english abstract). m. tóth, t., hollós, cs., szűcs, é. & schubert, f. (2004): conceptual fracture network model of the crystalline basement of the szeghalom dome (pannonian basin, se hungary).– acta geologica hungarica, 47, 19–34. m. tóth, t. (2008): repedezett, metamorf fluidumtárolók az alföld aljzatában.– academic doctoral thesis (in hungarian). m. tóth, t., redlerné tátrai, m. & kummer, i. (2009): structural evolution of the szeghalom metamorphic dome on the basis of petrological and seismic data magyar.– geofizika, 43, 143–151. (in hungarian with english abstract). manzocchi, t., childs, c. & walsh, j.j. (2010): faults and fault properties in hydrocarbon flow models.– geofluids, 10, 94–113. mátyás, j. (1994): diagenesis and porosity evolution of neogene reservoir sandstones in the pannonian basin (southeast hungary), phd thesis, university of bern, 196 p. moeller-pedersen, p. & koestler, a.g. (1997): hydrocarbon seals importance for exploration and production, norwegian petroleum society, special publications no. 7., elsevier science, singapore, 250 p. molnár, l., m. tóth, m. & schubert, f. (2014): statistical characterization of brittle and semi-brittle fault rocks: a clast geometry approach.– acta geodaetica et geophysica, (in press) doi number: 10.1007/s40438-014-0067-3 mort, k. & woodcock, n.h. (2008): quantifying fault breccia geometry: dent fault, nw england.journal of structural geology, 30, 701-709. nelson, r.a., 2001. geologic analysis of naturally fractured reservoirs. 2nd edition, gulf publishing company book division, houston, 322 p. pap, s. (1990): thrust-faulted sequences in transtisia.– special publications of the hungarian geological survey, budapest (in hungarian with english abstract). posgay, k., bodoky, t., hegedűs, e., kovácsvölgyi, s., lenkey, l., szafián, p., takács,e., timár, z. & varga,g. (1995): asthenospheric structure beneath a neogene basin in southeast hungary.in: cloetingh, s., d’argenio, b., catalano, r., horváth, f. & sassi, w. (eds): interplay of extension and compression in basin formation.tectonophysics, 252, 467-484. schubert, f. (2003): reconstruction of hydrocarbon-bearing fluid migration in the szeghalom dome (se hungary).– phd thesis, university of szeged, 158 p. (in hungarian). schubert, f., diamond, l.w. & m. tóth, t. (2007): fluid-inclusion evidence of petroleum migration through a buried metamorphic dome in the pannonian basin, hungary.chemical geology, 244, 357–381. storti, f., balsamo, f. & salvini, f. (2007): particle shape evolution in natural carbonate granular wear material.– terra nova, 19, 344-352. szederkényi, t., árkai, p. & lelkes-felvári, gy. (1991): crystalline groundfloor of the great hungarian plain and south transdanubia.in: karamata, s. (ed.): geodynamic evolution of the pannonian basin, beograd, 261-273. tari, g., horváth, f. & rumpler, j. (1992): styles of extension in the pannonian basin.– tectonophysics, 208, 203-219. tari, g., dövényi, p., dunkl, i., horváth, f., lenkey, l., stefanescu, m., szafián, p. & tóth, t. (1999): litho spheric structure of the pannonian basin derived from seismic, gravity and geothermal data.in: durand, b., jolivet, l., horváth, f. & séranne, m. (eds.): the mediterranean basins: tertiary extension within the alpine orogen. geological society, london, special publications, 156, 215-250. teleki, p.g., mattick, r.e. & kókai, j. (eds.) (1994): basin analysis in petroleum exploration. a case study from the békés basin, hungary. kluwer academic publishers. vass, i., m. tóth, t., szanyi, j. & kovács, b. (2009): water and heat flow through uplifted metamorphic highs in the basement of the pannonian basin.– in: m. tóth, t. (ed.): igneous and metamorphic rocks of the tisza unit. szeged, geolitera press, 325-339 p. (in hungarian with english abstract). wibberley, c.a.j. & shimamoto, t. (2003): internal structure and permeability of major strike-slip fault zones: the median tectonic line in mie prefecture, southwest japan.journal of structural geology, 25, 59–78. zhang, s., tullis, t. & scruggs, v. (2001): implication of permeability and its anisotropy in a mica gouge for pore pressure in fault zones.– tectonophysics, 335, 37-50. manuscript received september 11, 2014 revised manuscript accepted july 05, 2015 available online october 31, 2015 ab stra ct the görcsöny ridge is part of the complicated variscan metamorphic basement of the sw tisza plate. it was penetrated by several wells, one of which (baksa-2) has 1200 m of well core available for petrological examination. amphibolite samples of this core are of two different sorts: the fi rst group contains biot ite, rutile, and garnet, while the second group contains ilmenite and is free of garnet. the two rock types occur separately in the borehole, defi ning a lower and an upper unit (lu, uu). based on their major and trace element compositions, lu samples represent within-plate (wp) tholeiites which assimilated pelagic sediments, while those of the uu represent wp alkali basalts. thermobarometric calculations suggest that the difference in chemical composition itself does not explain the above differences in mineralogy, so the two units must also differ in their metamorphic histories. consequently, the crystalline basement of the görcsöny ridge possibly consists of amalgamated fragments of different origins which became juxtaposed during the variscan collisional orogeny. keywords: tisza plate, variscan orogeny, amphibolite geochemistry geochemistry of the görcsöny ridge amphibolites (tisza unit, sw hungary) and its geodynamic consequences  tivadar m. tóth department of mineralogy, geochemistry, and petrology, university of szeged h-6722 szeged, egyetem u. 2-6, hungary; (mtoth@geo.u-szeged.hu) doi: 10.4154/gc.2014.02 1. introduction the tisza unit (e.g. csontos et al., 1992) is a microcontinent which represents the european margin of tethys and reached its present location through horizontal microplate displacement during the alpine orogenic cycle. although palaeozoic and mesozoic sedimentary facies zones which cover the crystalline basement show a good correlation with those recognized in different tethian realms, (haas et al., 1995, and references therein), there are still many open questions concerning the relationships between the underlying crystalline rocks of the european variscan belt and those of the tisza plate. granitoid rocks of the sw part of the tisza unit (mórágy complex) were found to be similar to the rocks of the central bohemian massif, based on petrological and geochemical studies (buda, 1981) as well as age constraints (klötzli et al., 2004). according to szederkényi (1996), eclogite samples from the ne and sw part of the tisza unit represent a sw–ne trending sugeologia croaticageologia croatica ture zone of an ancient variscan ocean. szederkényi (1996) suggested a possible geological relationship between the low grade silurian black shales in the sw part of the tisza and those in the moravicum. if all these ideas fi t, the tisza unit should represent a composite segment of diverse tectonic realms of the european variscan belt. although at present correlating the evolution of the tisza basement with that of the european variscan belt is only a theoretical possibility, pamić et al. (2002) and balen et al. (2006) call attention to the close relationship between the basement of the görcsöny ridge inside the tisza plate and the slavonian mountains in croatia. they also offer a detailed evaluation of the geochemical and petrological data of diverse amphibolite types. the görcsöny ridge is located in the sw part of the tisza unit (fig. 1) bordered by tectonic lines in each direction. several boreholes penetrated the crystalline basement beneath the neogene clastic sediments, among which the geologia croatica 67/1 17–32 10 figs. 4 tabs. zagreb 2014 geologia croatica 67/1geologia croatica 18 isothermal decompression down to 4.4 ± 0.2 kbar at 650 ± 40 °c. this evolution seems to be typical for a significant part of the study area. the metamorphic history of the only known gyód serpentinite body is only partly similar, exhibiting a continuous retrograde pathway and hydration with significant recrystallization at ~650 °c and 4 kbar and serpentinization at ~250 °c (kovács et al., 2009). the appearance of post-kinematic antigorite and talc suggests a late reheating event, totally unknown from the surrounding gneiss terrain. as a consequence, serpentinite must represent a foreign tectonic regime inside the görcsöny complex. similarly, the only eclogite sample of the görcsöny-1 well suggests an exotic origin. recently, nagy & tóth (2009) called attention to the importance of textural relics in the lowermost section of the baksa-2 borehole, suggesting a significantly different metamorphic evolution in the upper and lower segments of the görcsöny ridge metamorphic block. all available data of the görcsöny complex represent variscan cooling ages (k/ar in amphibole and biotite, rb/sr in biotite, ar/ar in muscovite) for the amphibolite-facies metamorphic rocks (summarized in lelkes-felvári & frank, 2006 and references therein). to be able to correlate the görcsöny complex with other parts of the tisza unit and also with other segments of the european variscan belt, diverse geochemical, petrological and geochronological data must be considered. the aim of this study is to specify the chemical composition of the amphibolites in the görcsöny complex. in addition to the data deepest is the baksa-2 well, which has a total thickness of 1200 m and a core recovery close to 100%. the most common rock types throughout the görcsöny ridge are different kinds of gneiss and mica schist, marble, calc-silicate rocks, and amphibolite. additionally, one eclogite sample has been described by ravasz-baranyai (1969), while eclogite pebbles in the overlying miocene conglomerate were reported by horváth et al. (2003). among the many rock bodies, which show a significant positive magnetic anomaly, one has been exposed by a borehole and was proven to be a partially serpentinized ultramafic body (gyód serpentinite, balla, 1983; szederkényi, 1974; kovács et al., 2009). geochemical features of the amphibolite and eclogite samples throughout the görcsöny ridge were discussed by szederkényi (1983), who found them to be similar to mid-ocean ridge basalt (morb) tholeiites. the parent rock of gneiss and micaschist is thought to be a greywacke type sediment (szederkényi, 1977). geochemical and thermobarometric data prove that the protolith of the serpentinite body is of harzburgite composition, representing an oceanic upper mantle source (~1100 °c, 8.5 kbar, kovács et al., 2009). for the görcsöny complex gneiss and mica schist, szederkényi (1976) suggested a polyphase metamorphic evolution with five subsequent events, which was later simplified by árkai (1984) and árkai et al. (1985, 1999). for the earliest barrovian event they calculated a tmax of about 660 ± 25 °c at 7.5 ± 0.5 kbar pressure followed by an figure 1: tectonic sketch map of the tisza unit in the alpine-carpathian-pannonian framework. the arrow points to the study area. tivadar m. tóth: geochemistry of the görcsöny ridge amphibolites (tisza unit, sw hungary) and its geodynamic consequences geologia croatica 19 figure 2: a simplified tectonic map of the pre-neogene basement of southern transdanubia (after fülöp, 1994). a) görcsöny complex, b) gyód serpentinite, c) görgeteg complex, d) ófalu phyllite, e) mórágy granite, f ) carboniferous molasse, g) permian sandstone, h) triassic carbonates. inset: rock units of the baksa-2 well. um: upper marble; cg: chloritic gneiss; lm: lower marble; gg: garnetiferous gneiss; gs: garnetiferous mica schist. available so far (collected by szederkényi, 1983), the results of 34 new major and trace element measurements are included. as a result, the data of all known amphibolite bodies are included in the dataset even if some samples (no longer available) are represented only by their historical measurements. given the still obscure tectonic relationships, amphibolite data of the neighbouring units, mórágy granite complex (árkai & nagy, 1994) and ófalu phyllite zone, are disregarded in this study. 2. geological setting the crystalline basement of the sw part of the tisza unit is a complicated puzzle of blocks with incoherent metamorphic evolution histories (fig. 2). in the north, the görcsöny ridge is bordered by the ófalu phyllite zone, where various low grade rocks occur. to the east and northwest the görcsöny ridge is separated from the large anatectic granitoid body of the mórágy complex (balla & gyalog, 2009, and references therein). although there are essential petrological data that suggest a similar evolution (horváth et al., 2010), no direct information is available on the relationship between the görcsöny complex and the crystalline basement of northern croatia to the south because of the thick sedimentary cover. according to árkai (1984), the metamorphic evolution of the görgeteg-babócsa basement in the west is identical to that of the görcsöny complex, although their petrography differs slightly. based on the very sporadic information, the lithology of the western part is less complicated, consisting exclusively of gneiss and mica schist. the type locality of the study area is the baksa-2 well, which has been subdivided into five downward successions based on the dominant rock types. these are the “upper marble”, “chloritic two-mica gneiss”, “lower marble”, “garnetiferous two-mica gneiss”, and “garnetiferous two-mica schist” units (kovách et al., 1985, fig. 2 inset). in addition to marble, carbonate units also contain different calc-silicate rocks with tremolite, diopside, epidote, and garnet. in the gneiss and mica schist samples, garnet, staurolite, kyanite, and sillimanite are common; they usually contain a large amount of graphite (szederkényi, 1996). amphibolite bodies of different thicknesses appear concentrated in three sections along the well. numerous thin (up to about 50 cm) horizons appear between 830 and 870 m. at greater depths, within the lowermost units, two swarms of amphibolite occur in the 1020–1060 and 1130–1160 m intervals, respectively (fig. 2 inset). amphibole-plagioclase as well as amphibole-garnet thermobarometric calculations resulted in slightly different peak conditions for the different samples (550–690 °c at 4–5.5 kbar, árkai et al., 1999; 550–650 °c at 5–7 kbar, király, 1996). although only one eclogite sample has been reported from the crystalline basement itself (ravasz-baranyai, 1969), there are many eclogite pebbles in the overlying clastic sediments (horváth et al., 2003; lelkes-felvári gy. pers. comm.). the garnet amphibolite of the gy-3 well, like the eclogite, suggests a high dp/dt metamorphic peak: 7.5 kbar at 480 °c (király, 1996). textural relicts mostly appear as inclusions in large garnet grains of the garnetiferous two-mica gneiss and schist units, and were studied in detail by nagy & tóth (2009). among the common inclusions of quartz and ilmenite, kyanite as well as plagioclase, k-feldspar, apatite, and biotite grains of special appearance are observed. feldgeologia croatica 67/1geologia croatica 20 spar and apatite inclusions are usually faceted and have radial cracks around them, suggesting significant decompression during the metamorphic history (van der molen and van roermund, 1986). biotite exhibits symplectic intergrowth with worm-like quartz and rutile. thermobarometric calculations prove an early event of t ~ 680–720 °c and p ~ 8–9 kbar based on these inclusions. this metamorphic event is absolutely unknown from the upper units of the baksa-2 well. post-metamorphic palaeofluid evolution of the görcsöny complex was governed by two main subsequent events based on evaluation of the veins crosscutting the gneiss body (fintor et al., 2008, 2010, 2011). the early propylitic veins are characterized by the presence of diopside, epidote, and polymetallic ore minerals, pyrite, chalcopyrite, pyrrhotite, galena, and sphalerite (tarnai, 1997, 1998). this paragenesis formed in a wide temperature interval decreasing from 480 down to ~150 °c. late quartz-carbonate veins crystallized from a low temperature (130–60 °c) hypersaline fluid. although the presence of this second vein generation is common across the whole area, including the permo-carboniferous sedimentary cover formations (fintor et al., 2009), propylitic veins occur exclusively in the uppermost three units. all previous results considered, there are remarkable differences in the metamorphic and post-metamorphic evolution of the upper and lower segments of the studied well and probably also in different realms of the görcsöny complex. the two blocks are now referred to here as the upper unit (uu) and the lower unit (lu). 3. analytical methods whole rock compositions of 34 amphibolite samples were measured using an automated philips pw1453 x-ray fluorescence spectrometer with a sc-mo tube at the xrf laboratory of the university of fribourg (switzerland). major elements were determined from fusion discs fused in a pt crucible at 1000 ºc. the following trace elements were measured in pressed disks: v, cr, ni, ga, zr, y, nb, rb, sr, and ba. natural standards were used for the measurements. both major and trace element data have a relative precision better than 2%. historical geochemical data are collected in szederkényi (1983). electron microprobe measurements were performed at the montanuniversität, leoben, in austria using arl-semq 30 equipment with 15 kv accelerating voltage and 12 na figure 3: thin section photo micrographs of relic textures of the lu amphibolites. a) mica-rich band with symplectitic biotite grains (+n). b) fine-grained biotite+quartz symplectite of the lu amphibolite (+n). c) calcic myrmekite inclusions in amphibole (+n). d) plagioclase inclusions in garnet usually have faceted habit (+n). tivadar m. tóth: geochemistry of the görcsöny ridge amphibolites (tisza unit, sw hungary) and its geodynamic consequences geologia croatica 21 sample current. counting times of 20 s for si, al, mg, ca and k, and 30 s for fe, na, mn and ti were applied. for standardization, synthetic and natural mineral standards were used. the analytical error of the microprobe for the main elements (>10 m/m%) is less than 1%; for main and minor elements (2–10 m/m%) it is about 2%. 4. results 4.1. petrography 4.1.1. amphibolite at first sight, there are two distinct types of amphibole-bearing rocks in the baksa-2 borehole. in the upper marble unit, calc-silicate rock samples occur, which contain varying amounts of amphibole due to their different chemical bulk compositions as well as the p, t, and xco2 conditions during the metamorphic evolution. these samples have, without doubt, a sedimentary protolith, and have therefore been disregarded in the following study, which, instead, is focused on the rocks with magmatic origin. orthoamphibolite becomes an essential rock type below ~800 m in the baksa-2 borehole. the samples are massive, and in a few cases also foliated. they are dark green in colour and consist basically of hornblende with various amount of plagioclase. other constituents (quartz, garnet, biotite, and the ti-phases) occur in subordinate amounts. the mineralogical composition and textural features of the amphibolites change abruptly at the top of the garnetiferous two-mica gneiss unit (870 m, see inset of fig. 2). in the upper segment, medium grained, equilibrium texture amphibolite is common; relict mineral grains or textures are not observed. amphibole is normal hornblende; the prevailing ti-mineral is ilmenite, usually surrounded by titanite. the rock samples contain significantly more plagioclase than the samples of the lower segment of the well, while garnet, rutile, and biotite are entirely absent. in contrast, in amphibolite intercalations of the garnetiferous two-mica gneiss, relict mineral grains and textural domains have also been preserved. below about 1020 m the main ti-phase is rutile, usually mantled by ilmenite. within the 150 m interval between the two well-defined depths no amphibolite is present, making the exact specification of the border problematic. in the rutile-bearing part, garnet also appears in most samples, in general having a resorbed appearance and containing many rutile inclusions. garnet occasionally also occurs as an inclusion in the large amphibole grains. most amphibolite samples contain various amounts of biotite. in these mica-rich bands of the rock a fine-grained symplectite of biotite, quartz, and k-feldspar is common (fig. 3a, b). in addition to feldspar grains in textural equilibrium with amphibole, relict plagioclase occurs both as a matrix constituent and as an inclusion in amphibole and garnet. these sets of idioblastic plagioclase grains regularly form polygonal texture, and several crystals appear in vermicular intergrowth with quartz forming calcic myrmekite (fig. 3c) (dymek & schiffries, 1987). feldspar inclusions in garnet are usually faceted with common radial cracks at the crystal edges (fig. 3d). the abrupt change in amphibolite mineralogy and textures between the upper and lower units may be the result of a drastic change in either the bulk chemical composition or the metamorphic history of the two parts or both. 4.2. geochemistry although the chemical compositions of amphibolites may be significantly different from their parent igneous equivalents due to post-magmatic processes, these data sets are figure 4: amphibolite samples of the two units in the tas diagram (le maitre, 1989) suggest different compositions. inset: the alkaline-subalkaline discrimination after irvine & baragar, 1971. squares: uu; dots: lu. geologia croatica 67/1geologia croatica 22 table 1: chemical compositions of the amphibolite samples studied (oxides in m/m%, trace elements in ppm). unit uu uu uu uu uu uu uu uu uu uu uu uu sample b2-680 b2-681 b2-699 b2-701 b2-702 b2-703 b2-704 b2-706 b2-707 b2-708 b2-709 b2-711 depth 827 m 829 m 846 m 850 m 853 m 854 m 854 m 857 m 859 m 861 m 864 m 866 m sio2 49.09 48.88 47.22 46.24 47.13 47.49 50.43 48.15 46.67 47.49 46.48 44.73 tio2 3.17 3.29 2.62 2.75 3.81 4.26 2.92 3.01 3.14 2.86 3.34 3.76 al2o3 13.42 14.08 11.65 12.80 14.46 14.83 13.81 14.48 14.34 14.59 13.92 14.70 fe2o3 tot 11.78 11.65 13.49 14.33 12.14 14.19 13.69 13.47 13.84 12.74 13.22 15.85 mno 0.30 0.19 0.21 0.23 0.18 0.23 0.23 0.20 0.18 0.18 0.18 0.23 mgo 6.25 6.45 8.75 7.63 4.31 4.76 3.51 6.58 4.85 6.59 6.19 5.36 cao 10.36 9.67 11.27 10.64 11.01 8.61 8.72 8.32 10.94 9.51 10.67 8.67 na2o 3.10 3.18 2.51 2.61 4.13 4.15 5.20 3.69 3.25 3.55 3.07 3.34 k2o 1.15 1.32 0.82 0.99 0.57 0.87 0.50 1.17 1.24 0.85 1.21 0.43 p2o5 0.38 0.39 0.39 0.33 0.39 0.46 0.92 0.35 0.47 0.32 0.45 0.66 loi 1.22 1.32 1.19 1.06 1.68 0.62 0.36 0.89 1.02 1.01 1.17 2.68 total 100.21 100.40 100.12 99.61 99.81 100.45 100.29 100.32 99.93 99.72 99.89 100.41 cr 93 94 188 132 14 9 15 92 43 101 147 80 ni 79 62 97 89 15 11 1 65 30 66 65 31 v 398 428 342 396 403 421 174 372 397 378 409 381 rb 80 81 30 37 13 25 2 32 54 21 41 22 sr 433 492 235 305 450 511 416 553 429 430 426 491 ba 171 263 165 148 111 137 92 254 215 138 226 70 ga 18 21 15 19 26 25 24 22 22 21 21 33 nb 31 31 24 25 32 39 65 29 34 29 37 45 y 31 31 23 27 29 34 61 27 36 28 33 41 zr 186 190 148 141 184 223 400 193 213 174 206 238 unit lu lu lu lu lu lu lu lu lu lu lu lu sample b2-803 b2-804 b2-810 b2-811 b2-816 b2-828 b2-832 b2-833 b2-889 b2-907 b2-911 b2-913 depth 1020 m 1022 m 1035 m 1036 m 1044 m 1062 m 1066 m 1067 m 1128 m 1150 m 1152 m 1153 m sio2 55.59 50.07 49.95 49.84 43.65 50.06 47.87 50.43 48.98 49.74 47.45 48.78 tio2 1.40 2.10 3.83 0.86 3.62 2.94 2.68 2.72 2.11 2.82 3.07 3.75 al2o3 18.15 14.78 14.16 10.55 10.68 11.14 14.43 14.68 15.44 17.37 16.24 14.27 fe2o3 tot 8.27 11.69 14.21 12.25 14.74 13.22 12.03 12.59 12.99 11.75 12.24 13.75 mno 0.06 0.15 0.19 0.18 0.15 0.17 0.16 0.19 0.21 0.19 0.22 0.27 mgo 4.49 8.44 4.73 12.87 8.03 9.62 6.66 6.74 7.38 3.64 5.25 5.28 cao 3.89 7.55 8.31 10.04 14.10 9.08 8.12 8.27 9.02 10.87 11.23 10.08 na2o 3.20 0.68 1.31 0.83 0.89 0.88 2.23 2.27 1.39 0.99 1.09 1.94 k2o 1.74 2.39 1.59 0.97 0.78 1.29 1.80 0.97 1.02 0.88 1.45 1.04 p2o5 0.18 0.24 0.76 0.10 0.75 0.39 0.37 0.40 0.28 0.48 0.69 0.21 loi 3.05 2.26 1.25 1.86 2.27 1.65 3.45 1.07 1.62 1.29 1.33 0.77 total 100.01 100.35 100.28 100.36 99.65 100.44 99.82 100.34 100.44 100.01 100.25 100.13 cr 136 349 28 598 483 615 165 149 201 60 86 32 ni 44 84 25 477 417 188 93 90 74 33 47 6 v 257 298 455 141 283 366 372 328 357 316 382 378 rb 86 115 97 25 48 73 103 41 45 35 70 28 sr 269 115 132 35 129 34 173 152 131 282 233 262 ba 280 236 161 222 78 118 217 125 122 42 105 210 ga 20 21 29 17 25 18 19 18 24 35 34 24 nb 19 19 35 8 50 28 33 32 16 37 45 56 y 21 22 33 19 33 21 32 32 24 38 33 51 zr 177 130 200 82 308 154 196 192 122 244 219 360 tivadar m. tóth: geochemistry of the görcsöny ridge amphibolites (tisza unit, sw hungary) and its geodynamic consequences geologia croatica 23 unit lu lu lu lu lu lu lu lu lu lu lu lu sample b2-803 b2-804 b2-810 b2-811 b2-816 b2-828 b2-832 b2-833 b2-889 b2-907 b2-911 b2-913 depth 1020 m 1022 m 1035 m 1036 m 1044 m 1062 m 1066 m 1067 m 1128 m 1150 m 1152 m 1153 m sio2 55.59 50.07 49.95 49.84 43.65 50.06 47.87 50.43 48.98 49.74 47.45 48.78 tio2 1.40 2.10 3.83 0.86 3.62 2.94 2.68 2.72 2.11 2.82 3.07 3.75 al2o3 18.15 14.78 14.16 10.55 10.68 11.14 14.43 14.68 15.44 17.37 16.24 14.27 fe2o3 tot 8.27 11.69 14.21 12.25 14.74 13.22 12.03 12.59 12.99 11.75 12.24 13.75 mno 0.06 0.15 0.19 0.18 0.15 0.17 0.16 0.19 0.21 0.19 0.22 0.27 mgo 4.49 8.44 4.73 12.87 8.03 9.62 6.66 6.74 7.38 3.64 5.25 5.28 cao 3.89 7.55 8.31 10.04 14.10 9.08 8.12 8.27 9.02 10.87 11.23 10.08 na2o 3.20 0.68 1.31 0.83 0.89 0.88 2.23 2.27 1.39 0.99 1.09 1.94 k2o 1.74 2.39 1.59 0.97 0.78 1.29 1.80 0.97 1.02 0.88 1.45 1.04 p2o5 0.18 0.24 0.76 0.10 0.75 0.39 0.37 0.40 0.28 0.48 0.69 0.21 loi 3.05 2.26 1.25 1.86 2.27 1.65 3.45 1.07 1.62 1.29 1.33 0.77 total 100.01 100.35 100.28 100.36 99.65 100.44 99.82 100.34 100.44 100.01 100.25 100.13 cr 136 349 28 598 483 615 165 149 201 60 86 32 ni 44 84 25 477 417 188 93 90 74 33 47 6 v 257 298 455 141 283 366 372 328 357 316 382 378 rb 86 115 97 25 48 73 103 41 45 35 70 28 sr 269 115 132 35 129 34 173 152 131 282 233 262 ba 280 236 161 222 78 118 217 125 122 42 105 210 ga 20 21 29 17 25 18 19 18 24 35 34 24 nb 19 19 35 8 50 28 33 32 16 37 45 56 y 21 22 33 19 33 21 32 32 24 38 33 51 zr 177 130 200 82 308 154 196 192 122 244 219 360 unit lu lu lu sample b2-916 b2-917 b2-919 t-1/1 t-1/2 gy-3/1 gy-3/2 gy-4 o-1 g-1 depth 1156 m 1157 m 1158 m sio2 47.74 46.49 47.38 50.57 46.47 48.39 46.61 50.34 47.65 49.93 tio2 4.02 2.47 2.88 3.33 3.23 2.88 3.13 3.01 3.00 0.99 al2o3 14.48 15.14 15.06 15.14 14.57 13.98 14.23 14.42 14.45 18.37 fe2o3 tot 14.86 12.61 12.62 12.03 10.67 9.50 11.29 9.04 10.64 11.53 mno 0.22 0.18 0.20 0.16 0.21 0.21 0.26 0.16 0.18 0.18 mgo 5.26 5.23 5.26 4.20 7.42 6.53 7.36 7.10 7.54 7.32 cao 8.94 12.68 10.95 10.14 10.97 9.42 10.35 9.45 10.40 11.44 na2o 2.09 2.08 2.14 2.07 2.60 2.80 2.63 1.30 1.83 3.11 k2o 1.60 1.22 1.89 1.02 1.31 2.18 1.39 3.23 1.16 0.22 p2o5 0.45 0.37 0.31 0.27 1.16 1.02 1.13 0.89 1.05 0.05 loi 0.79 1.77 1.58 2.36 2.87 1.53 2.13 2.11 2.40 2.07 total 100.44 100.24 100.26 101.29 101.48 98.44 100.51 101.05 100.30 105.21 cr 14 79 109 n.d. n.d. n.d. n.d. n.d. n.d. n.d. ni 1 53 55 n.d. n.d. n.d. n.d. n.d. n.d. n.d. v 504 368 392 n.d. n.d. n.d. n.d. n.d. n.d. n.d. rb 57 52 98 n.d. n.d. n.d. n.d. n.d. n.d. n.d. sr 219 296 219 n.d. n.d. n.d. n.d. n.d. n.d. n.d. ba 378 122 235 n.d. n.d. n.d. n.d. n.d. n.d. n.d. ga 29 22 20 n.d. n.d. n.d. n.d. n.d. n.d. n.d. nb 41 28 36 n.d. n.d. n.d. n.d. n.d. n.d. n.d. y 32 30 28 n.d. n.d. n.d. n.d. n.d. n.d. n.d. zr 204 175 204 n.d. n.d. n.d. n.d. n.d. n.d. n.d. table 1: (continuation) geologia croatica 67/1geologia croatica 24 usually used for sketching the characteristics of the ancient igneous rocks. the major and trace element compositions of uu and lu amphibolites are evaluated below. 4.2.1. major elements the two petrographically different units show clear differences in their major element compositions (table 1). on the tas diagram (le maitre, 1989, fig. 4), rock samples of uu are plotted close to the alkali basalt field, while those belonging to lu are more differentiated and are subalkali in character (fig. 4 inset, irvine & baragar, 1971). using either zr or mg# (mg/(mg+fe)) as a differentiation index, the two sample groups exhibit different evolution trends for most elements on the series of harker diagrams (fig. 5). there are only a few outliers, probably affected by postmagmatic alteration processes. generally, the uu samples are characterized by lower si, k, and al and higher fe, ti, and na than those of the lu (table 1). co-variation of loi and mg# in both units suggests that, mainly because of the presence of amphibole and chlorite, samples with the most primitive composition are the most hydrated. for this reason, loi is insensitive to the effects of any post-magmatic processes and so the commonly used bivariate correlation between loi and na2o is not a suitable tool to test the origin of extra na in the uu. nevertheless, the low values (–0.14 for the uu, 0.10 for the lu) of the partial correlation coefficient between loi and na2o (controlling for mg#) suggest that na-concentration is independent of loi, and so the different na-content of the two units is probably a primary igneous feature. (the partial correlation coefficient is the correlation that remains between two variables after removing the relationship that is due to their mutual association with a third variable.) the same is true for k2o and al2o3, which exhibit even lower values than na2o in the analogous calculation for both units. weathering trends using major element diagrams of nesbitt & young (1989) indicate only a slight decrease in feo+mgo relative to the average basalt composition. nevertheless, in good agreement with the low partial correlation coefficients, no remarkable increase in either na2o or k2o is suggested. moreover, there is no difference in the weathering trends of the two groups on any of these plots, confirming that postmagmatic processes have only a subordinate role in the above chemical differences. figure 5: harker diagrams with mg# as a differentiation index. symbols as in fig. 4. tivadar m. tóth: geochemistry of the görcsöny ridge amphibolites (tisza unit, sw hungary) and its geodynamic consequences geologia croatica 25 the agpaitic coefficient ((na2o+k2o)/al2o3, molar proportions) in the uu is in the range typical for alkali basalts, varying between 0.43 and 0.52. for the lu, the agpaitic index varies around 0.21 for both the most and the least differentiated samples. even uu samples are, on the other hand, free of normative nepheline or acmite. mg# is below 60 for all but one sample and is therefore differentiated. some samples are even highly differentiated (mg# < 45). 4.2.2. trace elements the strong negative correlation between mg# and zr (–0.72) suggests that both variables are good indicators of igneous differentiation (fig. 5). ga, zr, nb, and y, elements which are usually immobile during the post-magmatic processes (e.g. wood et al., 1976; coish, 1977; morrison, 1978) increase with ongoing differentiation in both units, thus indicating incompatibility. cr and ni decrease during the fractionation, while the third transition metal (v) is slightly incompatible, similar to fe and mn. k, rb, ba, and nb slightly scatter in lu, while they exhibit a clear increasing trend in the case of the uu. sr shows a pattern similar to that of na2o. it is incompatible in both units, with remarkably, the highest concentrations in the uu. although n-morb normalized values for the two rock units show similar ranges for most elements, the typical spectra differ more in detail (table 2, figs. 6a and 6b). k, ba, and rb show significant gains in both cases, having larger concentrations in the lu. nb-enrichment up to 10*n-morb is typical for both sample groups. the uu samples are significantly higher in sr and ti than the lu ones. in the case of these two elements the lu is close to morb composition with element/morb ratios as low as 1–2. this also is typical for the y-content of both groups. uu samples are rather low in transition metals and exhibit a spectrum from the heaviest to the lightest elements with an approximately continuous slope, suggesting a pattern of pure igneous origin. also the very narrow range of element ratios, like rb/ nb (0.5–1.5) and k2o/nb (0.02–0.05), argues against any significant effect of post-magmatic enrichment processes. lu samples are similarly low in all elements relative to nmorb up to sr, while they show an abrupt enrichment for k, rb, ba, and nb, exhibiting a trend which suggests an average net gain. multi-element variation patterns in good agreement with the major elements show that uu samples are alkali basalts without any significant change of the original igneous composition. the lu elements, in contrast, represent subalkali basalts and basaltic andesites with enrichment of nb, k, rb, and ba, probably caused either by k-metasomatism or by assimilation of the upper continental crust or pelagic sediments (floyd et al., 1996). the positive nb anomaly, nevertheless, shows that assimilation of the lower crust is unlikely (thompson et al., 1982). 4.3. mineral chemistry a few amphibole and plagioclase compositions from both the upper and the lower amphibolites were presented previously by árkai et al. (1999) and used for thermobarometric calculations. in both units, amphibole exhibits a common hornblende composition, while matrix plagioclase varies around an33. as these results are confirmed by the new measurements, only the compositions of relict phases from the lu are given below (table 3.). garnet is not zoned; different grains in different samples have a constant composition table 2: average n-morb normalized compositions of the two units. n-morb composition is after sun & mcdonough (1989). element upper unit/ n-morb lower unit/ n-morb cr 0.25±0.15 0.60±0.60 ni 0.36±0.20 0.75±0.96 y 0.91±0.26 0.83±0.23 ti 1.97±0.29 1.70±0.55 zr 1.96±0.60 1.90±0.67 sr 4.26±1.35 1.58±0.74 nb 8.85±1.72 9.70±3.20 k 8.33±2.69 11.95±3.96 ba 11.9±4.20 12.7±6.33 rb 32.0±22 51.48±23 table 3: representative mineral compositions of relic phases from the lu amphibolites. grt pl inclusion in grt ilm inclusion in grt bt in bt-qz symplectite amp pl inclusion in amp sio2 38.18 54.80 0.00 39.22 43.11 46.94 tio2 0.18 0.00 51.35 2.66 0.48 0.00 al2o3 21.37 29.12 0.59 15.55 11.32 30.37 feo 29.16 0.16 47.05 16.49 16.47 1.18 mno 0.72 0.05 2.07 0.06 0.26 0.00 mgo 2.80 0.00 0.05 14.94 9.17 0.54 cao 7.87 9.93 0.12 0.00 10.49 19.20 na2o 0.00 4.60 0.00 0.00 0.90 0.74 k2o 0.01 0.10 0.00 8.98 0.44 0.07 total 100.34 98.77 101.23 98.11 92.69 99.04 no. o 12 8 3 22 24 8 si 3.01 2.48 0.00 5.69 7.04 2.20 ti 0.01 0.00 0.97 0.30 0.06 0.00 al 1.99 1.56 0.02 2.66 2.18 1.68 fe 1.92 0.01 0.99 2.00 2.25 0.05 mn 0.05 0.00 0.04 0.01 0.04 0.00 mg 0.33 0.00 0.00 3.23 2.23 0.04 ca 0.67 0.48 0.00 0.00 1.83 0.96 na 0.00 0.40 0.00 0.00 0.28 0.07 k 0.00 0.01 0.00 1.66 0.09 0.00 no. cation 7.98 4.94 2.02 15.54 16.00 5.00 geologia croatica 67/1geologia croatica 26 of alm61-63sps1-2prp10-12grs22-25. mn in ilmenite, surrounding rutile inclusions is as low as 0.04 p.f.u. symplectitic biotite is magnesian, having mg/(mg+fe) ~ 0.66 with ti ~ 0.33 and si ~ 6.00. the biotite of the matrix is much lower in ti, varying around 0.15 p.f.u. plagioclase in the qz-pl symplectite is ~ an90 both as amphibole inclusions and as a matrix constituent. plagioclase intergrown with biotite and quartz in the other symplectite type is a little more sodic, being an82ab15or3. for feldspar grains in the rutile-ilmeniteplagioclase inclusion assemblage in garnet (grips), an55 is typical. all these feldspar compositions differ significantly from those that characterize the matrix and represent the conditions of the amphibolite facies overprint. 5. discussion and conclusions 5.1. lu and uu discrimination 5.1.1. palaeotectonic setting of amphibolite formation the amphibolite samples of the baksa-2 borehole exhibit different chemical compositions as well as fractionation histories in the upper and the lower segments of the rock column. whether or not they formed in different palaeotectonic situations can be tested by a series of discrimination diagrams. several of these approaches (zr-ti-y, pearce & cann, 1973, fig. 6c; zr-nb-y, meschede, 1986; zrzr/y, pearce & norry, 1979, fig. 6d; ti/y-zr/y, pearce & gale, 1977; th-zr-nb, wood, 1979) give identical results; both the uu and the lu samples represent wp basalts. however, the two groups of samples define different clouds and trends on most of these plots due to the aforementioned differences in ti, zr, and nb. on the zr-zr/y plot, the uu samples define quite a flat trend, corresponding to an ol+cpx+pl-dominated fractional crystallization of an enriched mantle source. in contrast, lu samples define a steep line, suggesting a slight depletion relative to the primitive mantle (fig. 6d). this trend may be caused by fractional crystallization in which garnet is also involved. this also seems to be confirmed by the rapid decrease of cr along the differentiation path (from 607 down to 32 ppm), while zr increases from 83 to 362 ppm (pearce and norry, 1979). the incompatible behaviour of ga, however, disproves this idea as kd,ga gar/melt > 10. the rapid decrease of y shown in fig. 6d may be the result of amphibole crystallization as is also suggested by the flat curve of the v (zr:123 ® 362 ppm; v: 361 ® 380 ppm). considering all the diagrams discussed above, it is concluded that uu samples represent wp alkali basalt, while samples belonging to the lu are more differentiated wp andesites and basalts, which probably assimilated pelagic sediments. figure 6: geochemical data of the present study plotted on n-morb normalized spidergrams for a) uu and b) lu samples. data plotted on the c) zr-ti-y diagram (pearce & cann, 1973) (a, b: low-k tholeiites; b, c: calc-alkaline basalts; b: ocean floor basalts; d: within-plate basalts), d) zr-zr/y diagram (pearce & norry, 1979) (a: within-plate basalts; b: island arc basalts; c: mid-ocean ridge basalts; pm: primitive mantle; dm: depleted mantle; em: enriched mantle). symbols as in fig. 4. tivadar m. tóth: geochemistry of the görcsöny ridge amphibolites (tisza unit, sw hungary) and its geodynamic consequences geologia croatica 27 an alternative model would be the assumption of a similar alkali basalt protolith for both uu and lu. in this scenario the striking difference found in the chemical compositions would be the result of different post-magmatic alteration histories which caused net gains in k, rb, ba, and nb in the lu and relative increases in na and sr in the case of the uu. the total independence of the mobile components of loi, as well as clear co-variation of all these elements with zr, nevertheless, makes this model improbable. 5.1.2. discriminant function analysis the mineralogy and the major and trace element geochemistry shows that amphibolites of the baksa-2 well can clearly be divided into two distinct groups. whether the difference between the chemical compositions of the two sample groups is statistically significant or not can be checked using the independent samples t-test. comparing lu and uu samples element by element, at a significance level of 95% the difference becomes significant with regard to sio2, tio2, na2o, k2o, cr, sr, and rb. an initial attempt is made here to extend this division to all samples taken from the literature (szederkényi, 1983, and references therein) in order to be able to define subareas of the görcsöny ridge. discriminant function analysis (e.g. ragland et al., 1997, and references therein) based on the whole data set was applied for this purpose. this approach is suitable for calculating the optimal function of variables (the discriminant function), for distinguishing between two (or more) known sample groups (uu and lu amphibolites in the present case). in the calculations a stepwise method with wilks’ lambda minimization was used. it was found that the best function discriminating the two units is: d1 = 1.3 mgo + 1.1 na2o + 0.5 tio2 + 0.9 sr. using this linear combination of elements, the two groups can be clearly distinguished from each other (fig. 7a). this function confirms the previous observations that the uu samples are alkali basalts and hence are significantly higher in mg, na, ti, and sr than those of the lu. as there is a strong negative correlation between al and mg (r = –0.72), al does not appear in the above function. using only major elements for discriminating historical samples taken from the literature, the function has the form of d2 = 1.2 na2o – 0.6 al2o3 – 0.5 sio2. on the appropriate na2o – (al2o3+sio2) plot (fig. 7b), samples of the boreholes t-1 (one of the two), ok-1, and gy-4 undoubtedly belong to the lu, while the second sample of t-1, the g-1 eclogite, and both gy-3 samples lie at the border between lu and uu. each baksa-2 sample taken from the previous literature is plotted in the appropriate group defined by the whole database. 5.1.3. petrological modelling of the magmatic rock compositions although uu samples contain no normative nepheline, the other geochemical features discussed above undoubtedly prove that they represent alkali basalts. an independent way of performing cipw norm calculations is to reconstruct the primary mineral composition of the protolith by using thermodynamic calculations at the p-t conditions of crystallization. the domino/theriak code of de capitani (1994) is applied, which uses gibbs free energy minimization to compute the complete, stable assemblage at each p-t point. domino is particularly useful for analyzing relict parageneses because it computes the complete, stable assemblage at each stage of a given p-t evolution. provided the bulk composition of a rock is adequately estimated and the thermodynamic properties of all phases involved are sufficiently well known, then the computed phase diagram may be directly compared to the observed assemblages. given that each phase diagram is computed for a fixed bulk composition, the model must be sufficiently close to reality to represent all of the phases observed. the thermodynamic database used here is an extended version of berman (1988) with modifications from meyre et al. (1997). assuming a wide p-t window and constant fluid composition (t: 800–1300 °c, p: 3–8 kbar, feo/(feo+fe2o3) = 0.9, excess h2o) for the crystallization condition, lu samples contain ol, amp, cpx, pl, mag, kfs, bt, ilm, and qz  figure 7: a) plot of scores of the d1 discriminant function versus zr. b) na2o-(al2o3+sio2) plot for all görcsöny ridge amphibolites. borehole abbreviations are given in fig. 2. symbols as in fig. 4.; “+” denotes other wells; “x” stands for previous data for baksa-2 (szederkényi, 1983). geologia croatica 67/1geologia croatica 28 opx in different proportions (mineral abbreviations after whitney & evans, 2010). amphibole and biotite are missing above 900 °c. uu samples do not contain qz, and all but a few of them contain a significant amount of nepheline (up to 12 v/v%) in addition to the above phases. the amounts of pl (> 40 v/v%) as well as cpx (> 25 v/v%) significantly exceed the typical values of the lu (< 30 v/v% for pl, < 15 v/v% for cpx). the average modelled mineral compositions for both units are given as median values, interquartile ranges, and minimum and maximum values in table 4. given the significant bias from a normal distribution, mean and standard deviation values are not informative. gy-3, g-1, and t-1 samples, which are plotted at the border between uu and lu samples in fig. 7b, contain no nepheline based on the present calculation and are therefore more similar to lu. all things considered, the two exclusive model assemblages define quartz andesite (lu) and nepheline basalt or tephrite (uu) as the most likely protoliths. the two amphibolite types therefore represent different kinds of primary magmas and significantly different fractionation histories. 5.1.4. basic consequences for mineralogical composition the question of whether the above chemical differences can explain the observed differences in the mineral composition between uu and lu amphibolites should still be answered. the most striking difference is that uu rocks are free of rt, bt, and grt; moreover lu samples exhibit a wide spectrum of textural relics. garnet in the lu amphibolite cannot be an igneous relic phase because of the incompatible behaviour of ga (see above), and therefore must be metamorphic in origin. rutile, under identical physical conditions, can replace ilmenite in mg-rich rocks (raase, 1974); here however, rt appears exclusively in the lu samples which are lower in mg. so the stability field of this ti-phase must have been determined by a somewhat different p-t evolution for the lu samples. based on their common co-existence, the pre-kinematic, grtand rt-bearing paragenesis suggests an early higher pressure event for the lu section. although its amount is also hard to quantify, radial cracks around faceted plagioclase inclusions in garnet imply significant decompression (van der molen &van roermund, 1986) and thus suggest higher pressure metamorphism, too. as only a few garnet, plagioclase, and biotite grains with original composition have been preserved in the samples, there is only a very limited possibility to reconstruct the physical conditions of this early event. based on a domino/ theriak model using the measured biotite composition, the fine-grained bt+qz+kfs symplectite preserved suggests the presence of a previous orthopyroxene. the appearance of similar symplectites in mafic granulites was reported by ogilvie et al. (2004), barbosa et al. (2006), and dos santos et al. (2011), among several others, who explain opx breakdown due to the opx+kfs+liquid = bt+qz reaction, which is the same as the result of our model (fig. 8). others found this symplectite evidence for retrograde breakdown of garnet (prakash et al., 2012; grantham et al., 2013) or k-feldspar (waters, 2001; sajeev & osanai, 2004). there is, however no textural indication of garnet decomposition in the studied amphibolite samples. biotite has different compositions in diverse textural positions. matrix biotite is relatively low in ti and suggests a formation temperature of ~ 580 °c (fig. 9, henry et al., 2005) in accordance with the conditions previously calculated for the second metamorphic event. the fact that the ticontent of bt in opx replacing symplectite is twice as high, however, implies a formation temperature of 700–720 °c using the same approach (fig. 9). together with the above calculation, biotite appears around 710 °c at 7 kbar along a retrograde pathway. in a wide temperature range of 750–800 °c, the grips barometer (bohlen and liotta, 1986) table 4: model mineral compositions for uu and lu amphibolites under crystallization conditions. because of the significant bias from a normal distribution, the median and interquartile range (iqr) are used to characterize the data sets. phases uu lu median iqr min max median iqr min max cpx 27.0 7.9 4.5 49.1 13.4 9.3 4.0 39.0 ol 16.7 7.1 4.3 22.3 17.6 8.6 9.7 22.9 pl 40.2 8.1 21.9 53.8 30.1 8.1 17.8 41.1 kfs 4.8 1.9 2.1 18.6 4.9 2.8 3.1 9.4 qz 0 0 0 2.7 25.7 17.6 0.5 41.4 nph 1.8 4.7 0 11.3 0 0 0 0 mag 2.1 0.3 1.3 4.1 2.0 1.9 0.7 4.5 ilm 9.0 1.5 3.5 12.2 7.1 2.4 1.9 10.3 figure 8: summary of the thermobarometric data for the görcsöny complex. the solid line represents the results of previous calculations (király, 1996; árkai et al., 1999) for lu and uu samples, while the dashed line stands for the early evolution of lu amphibolites. ti-in-bt temperatures were calculated using henry et al. (2005); for grips paragenesis the barometer of bohlen & liotta (1986) was used. the opx breakdown reaction was computed with domino/theriak (de capitani, 1994) using the composition of symplectite biotite. tivadar m. tóth: geochemistry of the görcsöny ridge amphibolites (tisza unit, sw hungary) and its geodynamic consequences geologia croatica 29 shows 13–14 kbar for the rt+pl+ilm inclusion paragenesis in garnets of the lu amphibolites for five independent cases (fig. 8). although the presence of calcic myrmekite suggests ht metamorphic conditions (efimov et al., 2010), it is not suitable for estimating p-t conditions quantitatively. although there are only a few, uncertain thermobarometric data, the conflicting metamorphic evolutions for the lu and uu segments are proven, and an early hp metamorphic event followed by close to isothermal decompression for the lu amphibolites can be supposed. 5.1.5. geodynamic consequences in an opening continental rift region, igneous rocks of different compositions may form simultaneously, resulting in a significant overlap in both space and time. in the case of the görcsöny ridge, however, the diverse rock types occur separately, suggesting that the two segments may represent different realms of the same ocean. uu samples may have formed in the early phase of continental rifting and therefore represent a typical marginal sea, which is also confirmed by their metasedimentary rock surroundings (carbonates, graphite schist). lu, on the other hand, represents a sea mountain on a prior oceanic floor. the within plate geochemical character, (the trace element pattern that shows enrichment with respect to n-morb) is compatible with oib (ocean island basalt) origin. additionally, the appearance of ultramafic bodies in the görcsöny complex as well as the numerous reports of eclogite occurrences suggests that rocks of the görcsöny complex likely represent different segments of a juxtaposed consuming ocean, supporting a tentative threefold scenario sketched in fig. 10a–c. 1) the protoliths of the lu and uu amphibolites developed in various palaeotectonic settings (fig. 10a), resulting in different chemical compositions. 2) a subduction-related metamorphic evolution led to hp metamorphism of the lu, while the uu was affected exclusively by an mp event (fig. 10b). 3) probably due to reversal of the transport direction from subduction to uplift of the lu slice (e.g. following the model of chemenda et al., 1995), the two units became juxtaposed and exhibit identical metamorphic evolutions from this point on (fig. 10c). samples with geochemical characteristics similar to those of the uu of the baksa-2 well do not occur in the other wells studied, where lu rocks form the top of the basement. the spatial distribution of these wells (fig. 2) makes the spatial extension of the two distinct units approximately possible even in the absence of available petrological data in older wells. it is, nevertheless, worth mentioning that all known serpentinite bodies, eclogite, and garnetiferous amphibolite localities appear in the territory of the assumed extended realm of the lu, north of the baksa-2 well (fig. 10d). thermobarometric data calculated for lu amphibolites are consistent with the p-t evolution suggested by the relict assemblages of the host garnetiferous gneiss samples (nagy & figure 9: ti-in-biotite thermometric plots (henry et al., 2005) for bt+qz+kfs symplectite and matrix biotite. figure 10: a–c) a tentative threefold scheme for the geodynamic evolution of the görcsöny ridge (white square: uu; black square: lu). (d) theoretical n–s section across the görcsöny complex. for details see text. geologia croatica 67/1geologia croatica 30 tóth, 2009), implying that the early metamorphic phase can be extended for the whole lower segment of the baksa-2 well. furthermore, the results of the geochemical classification of the amphibolites suggest that this evolution may also be typical for a significant part of the görcsöny ridge. although the pre-metamorphic and early metamorphic histories of the two regimes differ significantly, the peak conditions of the last barrovian metamorphism in the two slices are identical (árkai et al., 1999). as the amphibole and biotite cooling ages are also the same in the two units (lelkes-felvári & frank, 2006), they probably became juxtaposed during the variscan orogeny and suffered the common retrograde evolution after nappe formation. this tectonometamorphic scheme is compatible with the slab break-off model developed by von blanckenburg & davies (1995) for the alpine evolution of the central alps. this process, nevertheless, was also found to be important for the exhumation of hp metamorphic rocks throughout the variscan orogeny (o’brien, 2000). published p-t paths for the hp granulites of the bohemian massif are rather similar to those reconstructed for lu rocks; these pathways are in general dominated by initial near-toisothermal decompression followed by a near-to-isobaric cooling stage (kotková, 2007). the resulting collisional orogen exhibits a rather complex structure in which the amalgamated continental and oceanic fragments are juxtaposed, being separated in large scale nappe systems (e.g. matte et al., 1990; oliver et al., 1993). the contrasting geochemical characters as well as metamorphic histories of the uu and lu blocks together with numerous previous results suggest that the görcsöny ridge is a tectonic assemblage of blocks of different metamorphic evolutions. blocks with different metamorphic evolutions were also inferred in the slavonian mountains, where, in addition to the common medium pressure varieties, amphibolites and host metapelitic rocks with peak conditions of 600–660 °c and 11–12 kbar also occur (balen et al., 2006; horváth et al., 2010). these observations further strengthen the genetic relationship between the two neighbouring areas inside the sw tisza. nevertheless, in order to specify similarities and differences between their evolution more accurately, further petrological studies must be performed. acknowledgement the project was financially supported by the otka foundation (grant no. f 017366). references árkai, p. (1984): polymetamorphism of the crystalline basement of the somogy-dráva basin (southwestern transdanubia, hungary).– acta mineralogica-petrographica, szeged xxvi, 129–153. árkai, p., nagy, g. & dobosi, g. (1985): polymetamorphic evolution of the south hungarian crystalline basement, pannonian basin: geothermometric and geobarometric data.– acta geologica hungarica, 28, 165–190. árkai, p., horváth, p. & nagy, g. (1999): a clockwise p-t path from the variscan basement of the tisza unit, pannonian basin, hungary.– geologica croatia, 52/2, 109–117. árkai, p. & nagy, g. (1994): tectonic and magmatic effects on amphibole chemistry in mylonitized amphibolites and amphibole-bearing enclaves associated with granitoid rocks, mecsek mountains, hungary.– acta geologica hungarica, 37/3–4, 235–268. balen, d., horváth, p., tomljenovic, b., finger, f., humer, b., pamić, j. & árkai, p. (2006): a record of pre-variscan barrovian regional metamorphism in the eastern part of the slavonian mountains (ne croatia).– mineralogy and petrology, 87, 143–162. balla, z. (1983): a dél-dunántúli ultrabázitok lemeztektonikai értelmezése. (plate tectonic interpretation of ultrabasites in southern transdanubia. in hungarian).– földtani közlöny, 113, 39–56. balla, z. & gyalog, l. (eds.) (2009): geology of the north-eastern part of the mórágy block: explanatory notes to the geological map-series of the north-eastern part of the mórágy block (1:10 000).– máfi, budapest,. 283 p. barbosa, j., nicollet, c., leite, c., kienast, j.r., fuck, r.a. & macedo, e.p. (2006): hercynite–quartz-bearing granulites from brejões domearea, jequié block, bahia, brazil: influence of charnockite intrusion on granulite facies metamorphism.– lithos, 92, 537–556. berman, r.g. (1988): internally-consistent thermodynamic database for stoichiometric minerals in the system na2o-k2o-cao-mgofeo-fe2o3-al2o3-sio2-tio2-h2o-co2.– journal of petrology, 29, 445–522. bohlen, s.r. & liotta, j.j. (1986): a barometer for garnet amphibolites and garnet granulites.– journal of petrology, 27, 1025–1034. buda, gy. (1981): genesis of the hungarian granitoid rocks.– acta geologica hungarica, 24, 309–318. chemenda, a.i., mattauer, m., malavieille, j. & bokun, a.n. (1995): a mechanism for syn-collisional rock exhumation and associated normal faulting: results from physical modelling.– earth and planetary science letters, 132, 225–232. coish, r.a. (1977): ocean floor metamorphism in the betts cove ophiolite, newfoundland.– contributions to mineralogy and petrology, 60, 255–270. csontos, l., nagymarosi, a., horváth, f. & kovać, m. (1992): tertiary evolution of the intra-carpathian area: a model.– tectonophysics, 208, 221–241. de capitani, c. (1994): gleichgewichts-phasendiagramme: theorie und software.– beihefte zum european journal of mineralogy, 72. jahrestagung der deutschen mineralogischen gesellschaft, 6, 48. dos santos, t.m.b., munhá, j.m., tassinari, c.c.g. & fonseca, p.e. (2011): the link between partial melting, granitization and granulite development in central ribeira fold belt, se brazil: new evidence from elemental and sr end isotopic geochemistry. – journal of south american earth sciences, 31, 262–278. dymek, r.f. & schiffries, c.m. (1987): calcic myrmekite: possible evidence for the involvement ofwater during the evolution of andesine anorthosite from st-urbain, quebec.– canadian mineralogist, 25, 291–319. efimov, a.a., flerova, k.v. & maegov, v.i. (2010): the first find of calcic myrmekite (quartz-plagioclase symplectites) in uralian gabbro.– geochemistry, 435/1, 1450–1455. fintor, k., schubert, f. & tóth t.m. (2008): hiperszalin paleofluidum-áramlás nyomai a baksai komplexum repedésrendszerében. (indication of hypersaline palaeofluid migration in the fracture system of the baksa complex. in hungarian).– földtani közlöny, 138/3, 257–278. fintor, k., tóth t.m. & schubert, f. (2009): a baksai komplexum posztmetamorf fluidum evolúciója. (post-metamorphic fluid tivadar m. tóth: geochemistry of the görcsöny ridge amphibolites (tisza unit, sw hungary) and its geodynamic consequences geologia croatica 31 evolution of the baksa complex in hungarian).– in: tóth, t.m. (ed.): magmás és metamorf képződmények a tiszai egységben. geolitera, 245–258. fintor, k., tóth t.m. & schubert, f. (2010): near vein metasomatism along propylitic veins in the baksa gneiss complex, pannonian basin, hungary.– geologia croatica, 63/1, 75–91. fintor, k., tóth t.m. & schubert, f. (2011): hydrothermal palaeofluid circulation in the fracture network of the baksa gneiss complex of sw pannonian basin, hungary.– geofluids, 11/2, 144–165. floyd, p.a., winchester, j.a., ciesielczuk, j., lewandowska, a., szczepanski, j. & turniak, k. (1996): geochemistry of early paleozoic amphibolites from the orlica-śnieżnik dome, bohemian massif: petrogenesis and palaeotectonic aspects.– geologische rundschau, 85, 225–238. fülöp, j. (1994): magyarország geológiája. paleozoikum ii. (geology of hungary. paleozoic ii. in hungarian).– akadémiai kiadó, 447 p. grantham, g.h., macey, p.h., horie, k., kawakami, t., ishikawa, m., satish-kumar, m., tsuchiya, n., graser, p. & azevedo, s. (2013): comparison of the metamorphic history of the monapo complex, northern mozambique and balchenfjella and austhameren areas, sør rondane, antarctica: implications for the kuunga orogeny and the amalgamation of n and s. gondwana.– precambrian research, 234, 85–135. haas, j., kovács, s., krystyn, l. & lein, r. (1995): significance of late permian-triassic facies zones in terrane reconstructions in the alpine-north pannonian domain.– tectonophysics, 242, 19–40. henry, d.j., guidotti, c.v. & thomson, j.a. (2005): the tisaturation surface for low-to-medium pressure metapelitic biotite: implications for geothermometry and ti-substitution mechanisms.– american mineralogist, 90, 316–328. horváth, p., kovács, g. & szakmány, gy. (2003): eclogite and garnetiferous amphibolite gravels from miocene conglomerates: new results for the variscan metamorphic evolution of the tisza unit (pannonian basin, hungary).– geologica carpathica, 54/6, 1–12. horváth, p., balen, d., finger, f., tomljenović, b. & krenn, e. (2010): contrasting p-t-t paths from the basement of the tisia unit (slavonian mts., ne croatia): application of quantitative phase diagrams and monazite age dating.– lithos, 117, 269–282. irvine, t.n. & baragar, w.a.r. (1971): a guide to the chemical classification of the common volcanic rocks.– canadian journal of earth sciences, 8, 523–548. király, e. (1996): adalékok a délkelet-dunántúli polimetamorf aljzat megismeréséhez. (contributions to the recognition of the polymetamorphic basement of se transdanubia. in hungarian).– földtani közlöny, 126/1, 1–23. klötzli, u., buda, gy. & skiöld, t. (2004): zircon typology, geochronology and whole rock sr-nd isotope systematics of the mecsek mountain granitoids in the tisia terrane (hungary).– mine ralogy and petrology, 81, 113–134. kotková, j. (2007): high-pressure granulites of the bohemian massif: recent advances and open questions.– journal of geosciences, 52, 45–71. kovách, á., svingor, é. & szederkényi, t. (1985): rb-sr dating of basement rocks from the southern foreland of the mecsek mountains, southern transdanubia, hungary.– acta mineralogicapetrographica, szeged xxvii, 51–56. kovács, g., tóth, t.m. & schubert, f. (2009): a gyódi szerpentinit metamorf fejlődése. [metamorphic evolution of the gyód serpentinite body – in hungarian].– in: tóth, t.m. (ed.): magmás és metamorf képződmények a tiszai egységben. geolitera, 81–100. lelkes-felvári, gy. & frank, w. (2006): geochronology of the metamorphic basement, transdanubian part of the tisza megaunit.– acta geologica hungarica, 49/3, 189–206. le maitre, r.w. (1989): a classification of igneous rocks and glossary of terms.– blackwell, oxford, 193 p. matte, p.h., maluski, h., rajlich, p. & franke, w. (1990): terrane boundaries in the bohemian massif: result of a large-scale variscan shearing.– tectonophysics, 177, 151–170. meschede, m. (1986): a method of discriminating between different types of mid-ocean ridge basalts and continental tholeiites with a nb-zr-y diagram.– chemical geology, 56, 207–218. meyre, c., de capitani, c. & partzsch, j.h. (1997): a ternary solid solution model for omphacite and its application to geothermobarometry of eclogites from the middle adula nappe (central alps, switzerland).– journal of metamorphic geology, 15, 687–700. morrison, m.a. (1978): the use of “immobile” trace element to distinguish the paleo tectonic affinities of metabasalts: applica tions to the paleo cene basalts of mull and skye, northwest scotland.– earth and planetary science letters, 39, 407–416. nagy, á. & tóth, t.m. (2009): relikt szöveti elemek a görcsönyi formáció óriásgránátos gneisz tagozat mintáiban [relict textures in the garnetiferous gneiss unit of the görcsöny formation – in hunga rian].– in: tóth, t.m. (ed.): magmás és metamorf képződmények a tiszai egységben. geolitera, 65–79. nesbitt, h.w. & young, g.m. (1989): formation and diagenesis of weathering profiles.– journal of geology, 97, 129–147. o’brien, p.j. (2000): the fundamental variscan problem: high-temperature metamorphism at different depths and high-pressure metamorphism at different temperatures.– in: franke, w., haak, v., oncken, o. & tanner, d. (eds.): orogenic processes: quantification and modelling in the variscan belt, 369–386. ogilvie, p., gibson, r.l., reimold, w.u. & deutsch, a. (2004): experimental investigation of schock effects in a metapelitic granulite.– 35th lunar and planetary science conference, march 15–19, 2004, league city, texas, abstract no. 1242. oliver, g.j.h., corfu, f. & krogh, t.e. (1993): u-pb ages from sw poland: evidence for a caledonian suture zone between baltica and gondwana.– journal of geological society, london, 150, 366–369. pamić, j., balen, d. & tibljaš, d. (2002): petrology and geochemistry of orthoamphibolites from the variscan metamorphic sequences of the south tisia in croatia – an overview with geodynamic implications.– international journal of earth sciences (geologische rundschau), 91, 787–798. pearce, j.a. & cann, j.r. (1973): tectonic setting of basic volcanic rocks determined using trace ele ment analyses.– earth and planetary science letters, 19, 290–300. pearce, j.a. & gale, g.h. (1977): identification of ore-deposition environment from trace ele ment geochemistry of associated igneous host rocks.– in: volcanic processes in ore genesis; geological society london publication, 7, 14–24. pearce, j.a. & norry, m.j. (1979): petrogenetic implications of ti, zr, y and nb variations in volcanic rocks.– contributions to mineralogy and petrology, 69, 33–47. prakash, d., singh, p.c., arima, m. & singh, t. (2012): p–t history and geochemical characteristics of mafic granulites and charnockites from west of periya, north kerala, southern india.– journal of asian earth sciences, 61, 102–115. raase, p. (1974): al and ti contents of hornblende, indications of pressure and temperature of regional metamorphism.– contributions to mineralogy and petrology, 45, 231–236. ragland, p.c., conley, j.f., parker, w.c. & van orman, j.a. (1997): use of principal components analysis in petrology: an geologia croatica 67/1geologia croatica 32 example from the martinsville igneous complex, virginia, u.s.a.– mineralogy and petrology, 60, 165–184. ravasz-baranyai, l. (1969): eclogite from the mecsek mountains, hungary.– acta geologica academiae scientiarum hungaricae, 13, 315–322. sajeev, k. & osanai, y. (2004): ultrahigh-temperature metamorphism (1150 °c, 12 kbar) and multistage evolution of mg-, al-rich granulites from the central highland complex, sri lanka.– journal of petrology, 45/9, 1821–1844. sun, s.s. & mcdonough, w.f. (1989): chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes.– in: saunders, a.d. & norry, m. (eds): magmatism in the ocean basins. geological society, london, special publications, 42, 313–345. szederkényi, t. (1974): paleozoic magmatism and tectogenesis in south-east transdanubia.– acta geologica academiae scientiarum hungaricae, 18, 305–313. szederkényi, t. (1976): barrow type metamorphism in the crystalline basement of southeast transdanubia.– acta geologica academiae scientiarum hungaricae, 20/1–2, 47–61. szederkényi, t. (1977): geological evolution of south transdanubia (hungary) in paleozoic time.– acta mineralogica-petrographica, szeged xxiii, 3–14. szederkényi, t. (1983): origin of amphibolites and metavolcanics of crystalline com plexes of south transdanubia, hungary.– acta geologica hungarica, 26/1–2, 103–136. szederkényi, t. (1996): metamorphic formations and their correlation in the hungarian part of the tisia megaunit (tisia megaunit terrane).– acta mineralogica-petrographica, szeged xxxvii, 143–160. tarnai, t. (1997): ore minerals from the key section of the baksa complex (w baranya hills, hungary).– acta mineralogica-petrographica, szeged xxxviii, supplementum, 119–133. tarnai, t. (1998): mineralogical-petrological study on ore vein penetrated by the key-borehole baksa no. 2, se transdanubia, hungary.– acta mineralogica-petrographica, szeged xxxix, 21–34. thompson, r.n., dickin, a.p., gibson, i.l. & morrison, m.a. (1982): elemental fingerprints of isotopic contamination of hebridean palaeocene mantle-derived magmas by archean sial.– contributions to mineralogy and petrology, 79, 159–168. van der molen, i. & van roermund, h.l.m. (1986): the pressure path of solid inclusions in minerals: the retention of coesite inclusion during uplift.– lithos, 19, 317–324. von blanckenburg, f. & davies, j.h. (1995): slab break-off: a model for syncollisional magmatism and tectonics in the alps.– tectonics, 14, 120–131. waters, d.j. (2001): the significance of prograde and retrograde quartz-bearing intergrowth microstructures in partially melted granulite-facies rocks.– lithos, 56, 97–110. whitney, d.l. & evans, b.w. (2010): abbreviations for names of rock-forming minerals. – american mineralogist, 95, 185–187. wood, d.a. (1979): a variably veined suboceanic upper mantle genetic significance for mid-ocean ridge basalts from geochemical evidence.– geology, 7, 499–503. wood, d.a., gibson, i.l. & thompson, r.n. (1976): elemental mobility during zeolite facies metamorphism of the tertiary basalts of eastern iceland.– contributions to mineralogy and petrology, 55, 241–254. manuscript received august 10, 2013 revised manuscript accepted february 13, 2014 available online march 21, 2014 2017 | 70/1 | 27–39 | 4 figs. | 6 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction diatomite is a porous, lightweight, siliceous sedimentary rock mainly composed of diatom skeletons formed in marine to freshwater environments of mid to high latitudes and contains >30% amorphous opaline silica (sio2·nh2o). commercial diatomite contains >60% of biogenic silica (bsi). mostly high-grade diatomite (>80% bsi) is used as diatomaceous earth (de), crushed and oven-dried inert dust with a minor content of calcium carbonate, volcanic glass and terrigenous particles (harwood, 2010). sediments that contains <30% of diatoms belongs to the tripolite. biogenic silica is non toxic to mammals and has been registered in many countries as a food additive. de is known as a potentially useful grain protectant because it is safe to use, does not affect grain end-use quality, provides long-term protection and is comparable in cost to other methods of grain protection (korunić, 2013). ideally, active de should have a high bsi content with a uniform particle size (less than 10 microns), a high oil sorption capacity, a large active surface, and very little clay and other impurities (korunić, 1998). lately, there are nume­ rous reports from around the world on the widespread resistance of several stored-product insects to grain protectants from the groups of synthetic pyrethroids, organophosphates, carbonates, croatian diatomites and their possible application as a natural insecticide ines galović1, josip halamić1, anita grizelj1, vlatka rozman2, anita liška2, zlatko korunić3, pavo lucić2 and renata baličević2 1 croatian geological survey, department of geology, sachsova 2, 10000 zagreb, croatia; (ingalovic@hgi-cgs.hr) 2 university of josip juraj strossmayer in osijek, faculty of agriculture in osijek, vladimira preloga 1, 31000 osijek, croatia 3 diatom research and consulting inc., 14 tidefal dr. toronto, on, mw 1j2, canada doi:10.4154/gc.2017.04 abstract in recent decades, there has been an increase in the use of diatomaceous earth (de) as a natural insecticide because of its low mammalian toxicity, worker safety, low risk of food residues and the occurrence of resistant insect populations associated with the use of chemical insecticides. therefore there is potential for research into known but previously undescribed croatian midmiocene marine diatomites from the perspective of their potential as proper de that could be mixed with plant extracts as a new formulation for grain storage protection. the marine diatomites belong to the paratethyan near shore environment, deposited in the upwelling zone during a mid-miocene temperate climate. palaeontological, mineral and geochemical analyses were done on ten promising marly sediments from 26 outcrops and one borehole from the north croatian basin. the most important ingredient of diatomaceous sediments is silica (biogenic opal-a and sio2 bound in other silicate minerals including quartz, clay minerals, micas, etc.). the amorphous silica content of the tested croatian diatomites is relatively low (� 50%) in comparison with the celatom® mn 51 standard (medium to high efficient de) (73.6%), nevertheless they show in some part even slightly better efficacy against insects. it seems that the enhanced content of smectite in diatomaceous sediments also influences increased absorption of de. based on palaeontological results, the most efficient diatomites from the podsusedsko dolje and markuševec (medvednica mt.) consist of the mid-sized planktonic coscinodiscus group of species where thalassionema nitzschioides dominate and is positively correlated with their absorption. the usage of boströms’ standard formula for getting opal-a from geochemical data was abandoned because of negative results and the modified murdmaas’ formula for hemipelagic sediments was applied. preliminary results on the aforementioned diatomite (as inert dusts) show good efficacy against tested insects sitophilus oryzae (linnaeus), tribolium castaneum (herbst) and rhyzopertha dominica (fabricius). article history: manuscript received november 17, 2016 revised manuscript accepted february 24, 2017 available online february 28, 2017 keywords: diatomite, palaeontology, mineralogy, geochemistry, natural insecticide, mid-miocene, croatia chlorinated hydrocarbons, bacilus thuringiensis, botanicals and chemicals (subramanyam & hagstrum, 1995; kljajić & perić, 2005). since only a physical method of controlling insects is involved in de, genetic resistance is generally unlikely according to ebeling (1971). however, a potential tolerance or even resistance should be considered when choosing de for replacing existing grain protectants (korunić, 1998; rigaux et al., 2001; fields, 2003; vayias et al., 2008). the efficacy of de against insects depends on the different properties of the diatom particles, including physical and morphological characteristics of diatoms, rather than on its origin. the physical property of diatomite is in its specific gravity (density) of diatom frustules (skeletons), which is about half that of water. the perforations (pores and striae) and open structure of diatom frustules renders diatomite a considerably lower density (0.12– 0.25 g/cm3) and high porosity (75–85%), able to absorb and hold up to 3.5 times its own weight in liquid i.e. in this case wax. well­ known diatoms with pores (areolas) have the physical ability to absorb wax (lipids) from the insects’ epicuticle, causing its dehydration and death (ebeling, 1971; korunić, 1998), according to high absorbency which speeds up the incorporation of oil. the earliest known croatian diatomites are from the podsusedsko dolje outcrops (medvednica mt.), and can be described as diatomaceous tripolite (outcrops j1­j4: pantocsek, 1903 g eo lo gi a c ro at ic a geologia croatica 70/128 system (pbs) (central paratethys) (pavelić, 2001; pave lić et. al., 2003) (fig. 1). this intracontinental region began to develop in the early miocene as a result of the african and european plate collision (horváth & royden, 1981). pbs is surrounded by the alps, dinarides and carpathian mountains. the evolution of the central paratethys was controlled by regional tectonic events, sea-level changes and connections with the mediterranean, boreal and indo­pacific oceans (steininger et al., 1988; rögl, 1996). these connections have been repeatedly disrupted and re-established until the end of the badenian when the sea level dropped, causing the beginning of the isolation and disintegration of the paratethys. at the beginning of the sarmatian, the connection with the other marine areas further weakened, and was followed by isolation; a stronger terrestrial influence favoured further decrease in salinity, resulting in changes to flora and fauna and their endemism. this was all more strongly influenced by climate changes. from the warmer period in the bade­ nian, the climate during the sarmatian becomes more moderate with seasonal oscillations (galović, 2001). in the sarmatian, the connections with the mediterranean and indo­pacific realms also existed, as shown by the last miocene transgression (rögl, 1998; kováč et al., 2001), and corroborated by investigations of siliceous microplankton (jurilj, 1957; hajós, 1986; galo vić & bajraktarević, 2006). the total thickness of the sarmatian deposits is relatively small (50 to 150 m), they predominantly consist of marly sediments of the tripolite type (bajrakta re­ vić et al., 1986) with rare limestones, clastic and volcanic fragments. such a small thickness is probably a consequence of the basin deepening (due to lithosphere cooling and compression at the end of the sarmatian) and less sediment input, which is characteristic of the early post­rifting phase (pavelić et al., 2003). and jurilj, 1957; outcrop b1: kochansky­devidé & baj­ raktarević, 1981; outcrops pd­ma: galović & baj­ rak tarević, 2006), and lopatice and gornja šemnica in hrvatsko zagorje (outcrops b2­b3: bajraktarević, 1984) (fig. 1). tripolite is a broad term, used in croatia for laminated marly sediments by many of the aforementioned authors. the first applied terminology of diatomite was used by gorjanović­ kramberger (1908) and jurilj (1957). during the investigations for the croatian basic geological map 1:50.000 from 2000 to 2004, a few more outcrops of diatomaceous tripolite (i.e. diatomite) were discovered in hrvatsko zagorje (cr), at medvednica, žumberak (jur­1 and jur­2) and požeška gora mts. seventy­ seven more diatom taxa were determined during those investigations on the podsusedsko dolje outcrops, where 23 were hitherto not known for the sarmatian (galović & bajraktarević, 2006). our investigations are part of the croatian science foundation (hrzz) project „development of new natural insecticide formulations based on inert dusts and botanicals to replace synthetic, conventional insecticides“ – diacromixpest conducted from 2014­2016 (rozman et al., 2015). throughout this research six more outcrops of diatomite have been discovered in the banovina region, two in slavonia and one at žumberak mt. (fig. 1). the palaeontological, mineralogical and geochemical results of croatian diatomites are presented here with their potential usage as de in agriculture for the protection of stored products. 2. geological setting the investigated mid-miocene (sarmatian) sediments of the north croatian basin (ncb) and hrvatsko zagorje basin (hzb), belong to the south-western marginal part of the pannonian basin figure 1. locations of investigated diatomites in croatia, pannonian basin system based on http://maps-for-free.com:  – j1-j4 (1903 to 1957) and b1-b3 (1981 to 1984);  – basic geological map of republic of croatia 1:50.000 from 2000 to 2009;  – this investigations with explanations in the text. g eologia c roatica i. galović et al.: croatian diatomites and their possible application as a natural insecticide 29 figure 2. the parts of the geological outcrops from medvednica mt. where the most effective croatian diatomite and tripolite were found. g eo lo gi a c ro at ic a geologia croatica 70/130 since the beginning of the miocene (23 ma; ogg et al., 2016), the most commercially exploited diatomaceous earth deposits are lacustrine in origin, although the largest producing deposit that outcrops near lompoc in california is a marine deposit of miocene age (dolley & moyle, 2003). nevertheless, other diatomites from paratethys are also marine deposits of miocene age from slovenia, austria, czech, slovakia, hungary and serbia (řeháková, 1977; hajós, 1986; horvat, 2004; roetzel et al., 2006; schütz et al., 2007; rojht et al., 2010). well known croatian diatomites from medvednica mt. belong to near shore mid-sarmatian marine sediments characteristic of the upwelling zone (galović & bajraktarević, 2006). individual parts of the ncb were uplifted and thus became source regions for clastic sarmatian deposits, accumulating in environments of reduced salinity (vrsaljko, 1999). through advanced ingression and deepening of the depositional environment, thin-bedded to laminated marls and sandstones accumulated (vrsaljko et al., 2005; vrsaljko, 1997). in the ncb sarmatian shallow-water gravels, biocalcarenites, and limestones were laid down, whereas later laminated marly deposits predominated, due to the deepening of the basin. for the region of the žumberak and samobor mts., sarmatian sediments consisting of calcite-rich marls and limestones with sandstone intercalations, crop out in a narrow zone along the badenian deposits, (vrsaljko, 2003). 3. materials and methods 3.1. field research with laboratory tests the representative sediments for diatom analyses belong to marl, tripolite, laminated marls, diatomite, varve, silt, clay and their varieties (fig. 2). the thicknesses of the sampled diatomites are small, approx. 48 cm. they are mostly laminated as a result of seasonality. among 26 well known sarmatian outcrops of diatomites in croatia, twelve were selected for further investigation: baničevac (bn) and opatovac (op) in slavonia, jurjevčani (ju) at žumberak mt., crkovec (cr) in hrvatsko zagorje, markuševec (ma) and podsusedsko dolje (pd) at medvednica mt. and bačuga (ba), martinovići (mr), prnjavor čuntički (pr), šušnjar (su), mali deanovići (md) and vukičevići (vu) in banovina. samples from the dolje borehole at podsusedsko dolje were also examined (d) (rozman et al., 2016) (fig.1). in total, 57 samples (each of ca. 10 kg) were taken for preliminary testing on their insecticidal efficacy by comparing them with standard medium to high effective celatom® mn 51. after testing, ten samples showed promising insecticidal efficacy and were selected for further analyses: ma­4, pd­1, pdk, d­01 and d­02b, ju­1, op­4 and op­4a (less laminated marls from the same horizont), mr10 (siltic marl) and mr-10b (mm laminated marl) and examined as natural pesticide (liška et al., 2015). sample pdk is mixture of all five pd samples, but milled to a diameter <45 μm for testing efficacy with smaller particles in the second year of the research project. based on their preliminary physico-chemical properties (palaeonto logical, mineral and geochemical analyses) only samples from medvednica mt. (fig. 2) were affirmed as diatomite. 3.2. palaeontology the standard preparation method used by the croatian geological survey is applied. approximately 1 cm3 of the sediment is placed in a beaker and treated with 30% concentrated hydrogen peroxide (h2o2) to oxidize organic matter for light microscope (lm) analyses. siliceous microfossil slides for sem preparations also include treatment with 20 % of concentrated hcl acid to remove carbonate and 10 % of sodium pyrophosphate to remove clay components. the sediments are then rinsed with distilled water. some of the samples were treated in an ultrasonic bath for approximately 15 seconds to improve disaggregation. standard smear slides and sem stub preparation techniques were used in slide preparation for both lm and sem analysis. the specimens were coated with gold and studied with a jeol jsm­35cf sem. smear slides were examined using a bh2 olympus lm. composition and diversity of diatom species together with their morphometric analyses are essential for the determination of de quality. quantitative methods were undertaken for 300 valves of diatom genera along transects under 500 x magnification (viličić, 2003; horvat, 2004). only whole diatom valves or their representative parts are counted according to schrader & gersonde (1978) and horvat (2004). diatom measurements were made using free imagej software (https://imagej.nih. gov/ij/). determined diatoms are traditionally divided into two orders: centrales (radial symmetry) and pennales (bilateral symmetry). 3.3. mineralogy x­ray powder diffraction (xrpd) was recorded on bulk samples, insoluble rock residue and the < 2 µm fraction of samples. some samples contained large amounts of carbonate minerals that had to be dissolved to eliminate overlapping diffraction peaks with other minerals. carbonate fractions were dissolved by acetic acid with an ammonium acetate (1 mol dm-3) buffer of ph 5 (jackson, 1956). clay minerals were determined on the < 2 µm fraction of samples on oriented mounts of air dried material, and after glycol treatment, heating to 400 ºc and 550 ºc (starkey et al., 1984). for quantitative analyses samples with 10% internal standard (zincite) were carefully weighed and ground with about 4 ml of methanol in a mccrone mill. for xrpd analysis a philips vertical x­ray goniometer (type x‘pert) equipped with a cu tube at the croatian geological survey (zagreb, croatia) was used. experimental conditions were: 45 kv, 40 ma, pw 3018/00 pixcel detector, primary beam divergence 1/4 º, and continuous scan (0.02 º2θ/s). quantitative analyses of the insoluble residue of samples were made using the rockjock® computer program (eberl, 2003). 3.4. geochemistry for better understanding of their mineralogical composition all selected samples were also analysed by xrf methods for the major oxides and some trace elements as ba, cu, ni, pb, sr, v2o5, zn, and zr in laboratories of the bureau veritas commodities ltd (vancouver, canada). a 5 g of sample was heated to determine the loss on ignition (loi). the treated sample was then fused in a platinum–gold crucible with a lithium tetraborate. the molten material is cast in a platinum mold. fused discs were analysed on panalytical axiosmax. the inductively coupled plasma atomic emission spectrometry/inductively coupled plasma emission mass spectrometry (icp­aes / icp­ms) methods for measuring trace elements were performed on 15 g samples. the 0.25 g split were heated in hno3-hclo4­hf to fuming and taken to dryness. the residue was dissolved in hcl. this preparation method is only partial for some cr and ba minerals and oxides of al, fe, hf, mn, sn, ta g eologia c roatica i. galović et al.: croatian diatomites and their possible application as a natural insecticide 31 table 1. diatom distribution with their morphometrics. legend: + scattered (< 5 %), rare (5–9 %), low abundance (10–15%), abundant (16–35%), high abundance (36–50%), dominant species (>50%) – species in fragments. diatom/sample pd-1 d-01 d-02b ma-4 ju-1 pdk size (μm) centrales               actinocyclus octanarius ehrenberg   + +     + 8–35 actinocyclus octanarius var. tenellus (breb.) hendey   +     + + 25–60 actinoptychus senarius (ehrenberg) ehrenberg   + +     + 20–62 anaulus minutus grunow +         + 10–16 anaulus simplex hajós +   +   + + 8–12 asteromphalus brunii pantocsek   +         32–44 coscinodiscus group (coscinodiscus, hyalodiscus, melosira, paralia, stephanopyxis, thalassiosira) + + 22 25 16 27   coscinodiscus apiculatus ehrenberg     +       – coscinodiscus curvatulus grunow + + 8 +   + 19– 37 coscinodiscus doljensis pantocsek   + + 17 + + 28–43 coscinodiscus miocaenicus krasske   +   +     18–21 coscinodiscus obscurus schmidt     +       38 coscinodiscus oculus iridis ehrenberg +   + + + + ≥40–75 coscinodiscus perforatus var. cellulosus grunow     +     + – coscinodiscus radiatus ehrenberg   + +       68–72 coscinodiscus rothii (ehrenberg) grunow   + + +     39–80 coscinodiscus rugulosus hajós   + +       14–30 coscinodiscus sarmaticus pantocsek     + + + + 12–31 hemiaulus cf. polymorphus           + 46 hyalodiscus laevis ehrenberg           + 20–50 hyalodiscus scoticus (kützing) grunow         + + 10–40 melosira dickiei var. fossilis pantocsek     +       12–20 melosira sp.         +   – paralia sulcata (ehrenberg) cleve + + + + + 7 12–40 perissonoë trigona (grunow) andrews & stoelzel           + – pseudopodosira westii (smith) sheshukova-poretzskaya & glezer     + +   + 12–29 rhizosolenia oligocaenica schrader   + + + + + – stellarima stellaris (roper) hasle & sims + + + + +   36 stephanopyxis turris (greville) ralfs +   +       63 thalassiosira leptopus (grunow) hasle & fryxell + + + + + + 34–65 resting spores and siliceous cysts (bacteriastrum spp., chaetoceros spp, liradiscus spp., xantiopyxis spp., periptera spp.) 6 59 + + 6 6 – triceratium balearicum cleve & grunow           + – t. laetum fa. quadrata hajós           + 28 pennales               achnanthes baldjiki (brightw.) grunow           + 32 achnanthes brevipes agardh   +         31 achnanthes rara jurilj   +       + 29–34 achnanthes saeptata var. sussedana jurilj         +   50 achnanthes spp.         +   – amphora binodis var. biggiba grunow +         + 28 amphora costata smith +         + 63 ardisonia fulgens (greville) grunow           + – biddulphia biddulphiana (boyer) smith     +   +   54–117 biddulphia sp.           + – caloneis boryana pantocsek           + 42 climacosphenia moniligera ehrenberg           + 16–18 cocconeis andesitica pantocsek           + 30 c. canaliculata jurilj           + 15 cocconeis conciata pantocsek +         + 26 c. disculus (schumann) cleve           + 14 c. distans gregory           + 40 c. evolvens jurilj           + 23 cocconeis fluminensis (grunow) peragallo +         + 28 c. quarnerensis var. lanceolata jurilj           + 20 cocconeis cf. sarmatica pantocsek +         + 11–28 cocconeis scutellum ehrenberg + + + + + 5 9–45 cymatosira lorenziana var. maior jurilj +         + 34–54 delphineis angustata (pantocsek) andrews   +         20–35 delphineis surirella (ehrenberg) andrews   + +       20 dimeregramma angustatum hajós         5   40 g eo lo gi a c ro at ic a geologia croatica 70/132 diatom/sample pd-1 d-01 d-02b ma-4 ju-1 pdk size (μm) centrales               dimerogramma boryanum pantocsek           + – dimeregramma distans gregory         +   39 di. minor (gregory) ralfs           + 12–17 di. minus var. neglectum jurilj           + – diploneis bombus ehrenberg         +   – diploneis coffaeiformis (schmidt) cleve           + – diploneis crabro (ehrenberg) ehrenberg     + +   + 22–45 diploneis fusca (gregory) cleve +         + 51 diploneis ovalis (brébisson) cleve + + + +   + 34 diploneis splendida var. porosa jurilj       +     – diploneis subovalis cleve     +     + 43–57 diploneis smithii (brébisson) cleve +       + + 30–50 diploneis sp.   +         – encyonema sp.           + – epithemia adnata (kützing) brébisson         +   46 epithemia zebra var. saxonica (kützing) grunow           + – eunotia cf. tenella (grunow) hustedt           + – fragilaria brevistriata grunow +     +   + 9–15 fragilaria construens (ehrenberg) grunow     +     + 8 grammatophora angulosa ehrenberg       +   + 28–32 grammatophora insignis grunow +       + + – grammatophora macilenta smith         +   25–80 grammatophora miocaenica hajós   +         28 grammatophora robusta ehrenberg       +     40–60 grammatophora oceanica ehrenberg   + +     + 37–93 g. oceanica var. macilenta (sm.) grunow           + do 172 g. oceanica var. oceanica ehrenberg           + – grammatophora stricta ehrenberg + +     + + 22–40 g. stricta var. biharensis ehrenberg           + – hantzschia virgata (roper) grunow         +   50–66 lyrella hennedyi (w.smith)stickle & mann + +       + 25–45 mastogloia binotata (grunow) cleve         +   40 mastogloia lacustris (grunow) grunow     +   +   38 mastogloia sarmatica jurilj +   +     + 69 m. splendida (gregory) cleve           + – mastogloia sp. + + +   9   – navicula latissima var. quadrata jurilj       +   + 64 navicula spp.   +     +   – nitzschia doljensis pantocsek   +         35 nitzschia frustulum (kützing) grunow     + +     18 nitzschia spp. +       +   – opephora gemmata fa. minor jurilj         +   40 opephora marina (gregory) petit           + 17 plagiogramma biharense pantocsek     +       15 plagiogramma bipunctatum hajós +           – plagiogramma staurophorum (gregory) heiberg +   +   + + 20–30 planothidium quarnerensis (grunow) witkowski,lange-bertalot & metzelin         + + 20 rhabdonema hamuliferum kitton         12   – rhaphoneis amphiceros ehrenberg         + + 17–32 rh. amphiceros var. rhombica grunow           + – rh. cocconeiformis (schmidt) hanna & grant           + – rh. nitida (gregory) grunow           + – rhaphoneis rhombica (grunow) andrews +         + 34 rhopalodia gibberula (ehrenberg) müller +       + + 34 staurosirella leptostauron (ehrenberg) williams & round         +   10–26 staurosirella pinnata (ehrenberg) williams & round   +         22 surirella subfastuosa pantocsek         +   – synedra crystallina var. fossilis pantocsek           + – synedra fulgens (greville) w.smith +   +   +   – synedra tabulata var. obtusa pantocsek         +   – thalassionema nitzschioides (grunow) grunow 69 32 74 60 30 8 33–139 thalassiotrix longissima cleve & grunow 8   + + + + 34 table 1. continued g eologia c roatica i. galović et al.: croatian diatomites and their possible application as a natural insecticide 33 and zr. additionally, volatization during fuming may result in some loss of as, s and sb. the analyses were done by spectro cirios vision icp­aes and perkin elmer elan 6000/9000 icp-ms. inorganic carbon was determined by directly measuring the co2 gas evolved into the leco cs230 analyzer when a prepared sample split is leached with perchloric acid. from the last century, the boströms’ standard formula (boström at al., 1972) for estimating biogenic silica from geochemi­ cal data was used: opal-a= sio2 (total) – 3·al2o3 we tested and abandoned this formula because of a negative result for sample mr­10b, (tab. 5). therefore murdmaas’ modi­ fied formula (murdmaa et al., 1980) for extracting opal­a from hemipelagic sediments was used: opal-a= sio2 (total) – 2.7∙al2o3 3.5. insecticidal efficacy in order to test insecticidal efficacy of inert dusts against rice weevil, s. oryzae, 100 grams of clean soft wheat of different varieties (approx. 13% m.c.) was mixed with a determined quantity of each dust in glass jars of 200 ml. fifty unsexed adults of s. oryzae, 7­21 days old were added into each jar. inert dusts were tested in 3 or 4 different doses, depending on inert dust, and all treatments were conducted in 4 repetitions. bioassay was kept under controlled conditions at 28±2 °c, 65 ±5 % rh and in dark. insecticidal efficacy was estimated as lethal doses required to kill 50% and 90% of the tested population (ld50 and ld90). the ld50 and ld90 values were calculated by probit analysis using ibm spss statistics (ibm corp. released, 2013). 4. results 4.1. palaeontology in total, in samples from medvednica and žumberak mts, 111 diatom species were determined with fourteen variants and two forms. among them, four species had not been previously discovered in podsusedsko dolje: chaetoceros didymus ehrenberg, dimerogramma minus (gregory) ralfs var. neglectum jurilj, rhaphoneis cocconeiformis (schmidt) hanna & grant and rh. nitida (gregory) grunow. approximately 90% of the diatom species are less than 50 μm in size, while larger specimens are mostly broken (galović et al., 2015). diatom distribution with their sizes is given in table 1. to emphasise the physical character of diatomite as a potential natural pesticide. the most abundant species in the samples belong to the coscinodiscus group, thalassionema nitzschoides and chaetoceros group with resting spores and siliceous cysts. based on palaeontological results, the most prospective diatomite (tripolite) for commercial use would be from medvednica mt. (ma­4, pdk, d­02b), fig. 3. the dominant species in sample ma­4 is figure 3. sem images of partially crushed diatom thalassionema nitzschioides on the left an coscinodiscus curvatulus on the right from the sample d-02b. table 2. quantitative mineral composition of samples (in wt. %) obtained by xrd analysis using rockjock® computer program (eberl, 2003). ** – abundant (20–40%), * – subordinate (1–20%), + – traces (<1%) minerals ma-4 pdk d-01 d-02b ju-1 op-4 op-4a mr-10 mr-10b quartz 5 3 5 4 2 2 1 2 2 opal-a 28 12 41 50 11 3 opal-c + + 1 1 calcite 19 30 10 11 28 7 6 69 64 aragonite 34 40 73 81 feldspar 1 2 1 1 1 1 pyrite 2 clay minerals 47 19 44 33 18 16 10 25 34 smectite ** * ** ** * * * * * illit/muscovite * * * * * * * * * chlorite * + kaolinite * + + + + g eo lo gi a c ro at ic a geologia croatica 70/134 4.3. geochemistry the results of geochemical analysis for major elements are shown in table 3. the concentration of total silica in samples varies from 3.96 to 61.91%. the measured content of sio2 in most samples is relatively small (< 47.71%) except for the samples from the borehole podsusedsko dolje (d­01 and d­02b; 55.58 % and 61.91% respectively). in comparison to the standard sample (celatom® mn 51) the majority of analysed samples have a high content of cao (> 35%) and relatively high content of mgo (tab. 3). the high content of carbonate component in the samples results in high values of loi (>18.60%). the measured content of trace elements of nine de samples is given in table 4. it is significant that the concentrations of mo and cu are higher in samples from medvednica mt. than form elsewhere. the highest concentration of pb (19.4 mg/kg), which exceed the recommended value of 15 mg/kg for diatomaceous earth of standard sample, is determined in sample ma­4 from medvednica mt. (tab. 4). the samples from medvednica mt. and samples mr-10 and mr-10b from banovina region also have increased concentrations of ni (>50 mg/kg). the elevated concentrations of uranium, especially in sample mr-10 from banovina, are connected to the higher content of organic matter. 4.4. insecticidal efficacy on common stored pests results among our samples of inert dust efficacy against rice weevil (rw), s. oryzae are shown in table 6., where the highest efficacy is seen in samples d­01, d­02b and ma­4. 5. discussion the results of xrpd analyses showed that all analysed samples contain greater or lesser amounts of opal-a and quartz (tab. 2). quantitative analyses of the mineralogical composition of samples obtained by xrpd analyses (tab. 2.) gave larger amounts of opal silica than results of calculations by boströms’ and murdmaas’ formulas (tab. 5). these types of calculations are based on the assumption that the sio2/al2o3 ratio in terrigenous clay and silty clay is almost constant, and varies from 3.5 to 2.7. according to grizelj et al. (2007; 2017) xrpd analyses of miocene pelitic sediments from the croatian part of the pbs revealed that most of the samples contain the same mineral phases, but they are present in different quantities in different samples. the ratio of sio2/al2o3 can vary within one clay mineral group and varies considerably within different clay mineral groups. clay minerals have a wide range of variations in chemical composition and the variation is a composite of all the errors inherent in any thalassionema nitzschioides in an assemblage with abundant smaller species of coscinodiscus curvatulus, c. doljensis and bigger but mostly fragmented thalassiosira leptopus. in the pdk dominant diatoms include coscinodiscus oculus iridis, thalassiosira leptopus, coscinodiscus stellatis and paralia sulcata. 4.2. mineralogy the mineralogical composition of the insoluble residues of the analysed rock samples is given in table 2. the main components of all samples are carbonate minerals (calcite and/or aragonite), clay minerals and opaline silica (biogenic opal-a with very small amounts of mineral opal-c in some samples). opal-a (highly disordered, near amorphous) produces a single broad peak centred at approximately 4 å (fig. 4) and opal­c (well­ordered α­cri sto­ balite) at 4.04­4.06 å (jones & segnit, 1971). all analysed samples contain quartz (sio2) ranging in content from 1­5%. some samples contain smaller amounts of feldspar and pyrite. table 3. major and trace elements content measured by xrf method (in %) in croatian diatomites and major elements in celatom® diatomaceous earth functional additive celatom® mn 51 standard. sample/ element sio2 al2o3 fe2o3 cao mgo na2o k2o mno tio2 p2o5 loi sum*** of trace elements sum tot/c ma-4 47.71* 8.81 3.85 9.63 0.92 0.37 1.43 0.07 0.41 0.10 23.44 2.218 98.96 9.65 pdk 21.26 4.51 1.98 36.29 0.67 0.47 0.59 0.03 0.25 0.11 33.33 0.002 99.51 – d-01 55.58 6.83 2.85 5.59 1.30 0.25 1.05 0.04 0.31 0.21 22.52 2.442 98.97 8.56 d-02b 61.91 5.31 2.20 6.13 1.13 0.19 0.82 0.02 0.27 0.06 18.60 2.326 98.97 5.83 ju-1 18.65 3.15 1.34 38.10 0.49 0.21 0.44 0.04 0.16 0.10 35.22 1.048 98.95 10.07 op-4 7.37 2.32 0.97 44.72 0.34 0.48 0.19 0.005 0.12 0.007 41.31 1.345 99.24 10.76 op-4a 3.96 1.31 0.40 49.26 0.24 0.39 0.09 0.02 0.07 0.11 42.78 1.105 99.74 11.61 mr-10 14.21 4.73 1.57 37.15 1.89 0.24 0.83 0.07 0.24 0.08 36.53 1.541 99.08 10.42 mr-10b 16.22 5.44 2.05 36.90 1.42 0.16 0.92 0.07 0.23 0.07 35.04 0.728 99.25 9.93 celatom® mn 51** 73.60 7.80 1.80 5.60 0.30 sum other oxides 2.30 – 5.50 – 96.90 – * in % ** standard de *** measured trace elements: ba, cu, ni, pb, so3, sr, v2o5, zn, and zr. table 4. trace element content in croatian diatomites (mg/kg). sample/ element ma-4 pdk d-01 d-02b ju-1 op-4 op-4a mr-10 mr-10b mo 24.4 17.4 20.2 14.4 2.2 2.3 0.8 98.7 8.0 cu 46.8 32.9 41.5 82.9 21.3 24.6 31.0 37.9 31.4 pb 19.4 6.9 14.7 11.8 5.6 10.8 4.3 10.4 12.9 zn 75 33 65 63 27 23 14 48 52 ni 113 81 89 81 31 35 13 133 62 co 21 6 16 8 5 5 2 11 5 as 15 7 7 5 10 5 0.05 5 6 u 8 10 6 4 5 8 6 36 8 th 8 3 6 4 2 2 1 3 3 sr 518 3405 427 549 3438 6405 5161 1745 1653 cd 0.8 6.2 0.8 4.5 0.8 1.1 0.3 2.9 1.6 sb 1.8 0.9 1.3 1.7 0.6 2.2 0.4 4.1 2.0 bi 0.5 <0.1 0.3 0.2 0.1 0.2 0.1 0.2 0.2 v 104 64 75 81 43 23 17 51 60 la 24 12 17 12 8 9 5 10 12 ba 275 340 183 168 336 176 170 632 679 w 1.4 <0.5 1.2 0.8 0.5 0.4 0.2 0.6 0.6 ce 54 21 35 23 15 17 9 20 24 sn 2.4 1.0 1.6 1.3 0.7 0.8 0.6 1.1 1.3 y 19 13 14 9 6 10 7 7 8 nb 6 4 5 4 2 2 1 3 4 ta 0.5 0.3 0.4 0.3 0.2 0.1 0.05 0.2 0.2 sc 12 5 8 7 3 3 2 6 7 li 40 23 35 29 14 12 9 25 30 se 5 3 4 3 2 3 3 11 4 zr 39 49 34 26 22 8 6 22 25 celatom® diatomaceous earth functional additive standard celatom® mn 51: pb = 15 mg/kg, as = 20 mg/kg. g eologia c roatica i. galović et al.: croatian diatomites and their possible application as a natural insecticide 35 analytic analysis: operator, instrument, method, beneficiation, sampling (weawer and pollard, 1973; weaver 1989). according to the geochemical analyses there is a significant variation in the total silica (sio2) content in samples collected on figure 4. xrpd pattern of bulk sample d-02b, and insoluble rock residue of sample ma-4. table 6. efficacy of 9 croatian inert dusts and standard celatom® mn 51 against sitophilus oryzae (l.) adults after 7 days of exposure with ld50/ld90 values (95% fiducial limits). inert dust lethal doses (ppm) ld50* ld90* d-01 156.5 (62.28-213.26) 447.2 (419.88-481.90) d-02b 300 ppm=82.5% 359.6 (240.55-422.56) ju-1 351.4 (324.22-373.43) 606.7 (575.90-648.08) ma-4 232.2 (183.05-266.05) 458.7 (436.21-487.52) mr-10 693.3 (646.91-778.77) 954.1 (847.50-1159.46) mr-10b 588.6 (564.40-623.79) 831.1 (763.36-944.09) op-4 421.5 (346.71-460.50) 867.7 (750.76-1161.96) op-4a 534.8 (517.44-555.17) 744.4 (699.14-813.40) pd-1 362.8 (314.80-391.50) 726.4 (668.39-816.94) celatom® mn 51 300 ppm=83.5% 334.1 (86.64-399.00) *lc50 and ld90 expressed as parts per million (ppm), confidence limits (cl) are given in parentheses table 5. content of opal-ab according to standard boströms’ formula (boström at al., 1972) and opal-am according to modified murdmaas’ formula (murdmaa et al., 1980). sio2 and al2o3 are from table 3. element/ mineral m a4 pd k d -0 1 d -0 2b ju -1 o p4 o p4a m r10 m r10 b sio2 47.71 21.26 55.58 61.91 18.65 7.37 3.96 14.21 16.22 al2o3 8.81 4.51 6.83 5.31 3.15 2.32 1.31 4.73 5.44 3∙al2o3 26.43 13.53 20.49 15.93 9.45 6.96 3.93 14.19 16.32 2.5∙al2o3 23.79 12.18 18.44 14.34 8.50 6.26 3.54 12.77 14.69 opal-ab 21.28 7.73 35.09 45.98 9.20 0.41 0.03 0.02 –0.10 opal-am 23.92 9.08 37.14 47.57 10.15 1.11 0.42 1.44 1.53 g eo lo gi a c ro at ic a geologia croatica 70/136 the medvednica mt. (21.26% sample pdk, 47.71%, sample ma­ 4, and 61.91% sample d­02b) (tab. 3). this is particularly evident at the podsusedsko dolje site, where the distance from the sample pdk and samples d­01 and d­02b is about a kilometre. late­ rally marked variations in the silica content of the investigated diatomites are most likely the result of the marine geomorphology of the depth and its variations during the mid-sarmatian, as well as diagenesis and tectonic processes that modify the composition and crystalline phase of the mineral. this also applies to the sio2 content at the jurjevčani (18.65%) site (žumberak mt.), which is significantly lower than the average silica content on the medvednica mt. (mean = 48.63%) considering that the direct distance from the podsusedsko dolje site is only 25 km today. this is in accordance with their origin where the most prospective diatomites from medvednica mt. belong to the upwelling zone of the temperate climate with seasonal blooming (galović & bajraktarević, 2006), while that from žumberak belongs to a more coastal marine area. the concentration of silica in the samples from banovina is lower than that registered in the samples from the medvednica and žumberak mts. (tab. 3). the lowest content of sio2 is found in the samples from slavonia (op: ≤7.37%) which is why we advocate tripolite instead of ordinary diatomite. the sio2 concentrations in those analysed samples are more depleted in comparison with the standard celatom® mn­51. the concentration ranges from 3.96 to 7.37% sio2 (tab. 3). the insecticidal effect of des against stored product insects greatly depends on the amount of biogenic silica (korunić, 2013). samples with the lowest concentration of silica have the highest carbonate component (cao) content. according to fields & muir (1995) calcium oxide also has some insecticidal activity. samples ju, op and mr have enhanced cao (36.90­49.26%) which could be a reason why they showed promising insecticidal efficacy in preliminary testing. all samples except d-01 and d-02b have much higher contents of cao compared to the standard sample (tab. 3). the mgo content is in most samples associated with the cao content which is probably due to the originally precipitated dolomite in association with calcite. the content of alumina depends on the amount of the clay component in the sample. in relation to celatom® mn 51 only one analysed sample, ma­4, has a slightly elevated content of alumina (al2o3), which is probably a part of the detected smectite which increased its adsorption (tab. 2 and 3). the fe2o3 content is slightly higher in all analysed samples from the medvednica mt. as well as in the sample mr-10b (banovi na) in comparison to celatom® mn 51. the highest concentration of iron registered in the sample ma­4 from the medvednica mt. probably originates from the chlorite mineral group occurring in the sample (tab. 2). the sum of all other oxides (na2o, k2o + mno + tio2 + p2o5) in the analysed samples of croatian diatomites is smaller than their content in celatom® mn 51 (tab. 3). among the trace elements, only the concentrations of potentially toxic lead (pb) and arsenic are of importance. the amount of pb exceeds the limit values relative to celatom® mn 51 (15 mg/kg) solely in the sample ma­4 (19.4 mg/kg) from medvednica mt., while the concentrations in all other samples are lower. enhanced lead might be a result of the weathering of the galenite ore deposit there. the content of arsenic (as) is significantly lower in all analysed samples compared to sample celatom® mn 51 (tab. 4). the highest efficacy against the rice weevil, s. oryzae show ed in samples d­01, d­02b and ma­4 (tab. 6). samples d­01 and d­02b have smaller amounts of quartz (4­5 %) and maximum amount of opal­a (41­50%), as bsi, which make them suitable for commercial usage as de (tab. 2, fig. 4). as a bsi component, thalassionema nitzschioides dominate in the assemblage with abundant, bigger species (65­80 μm) of coscinodiscus group (coscinodiscus oculus iridis, thalassiosira leptopus, coscinodiscus radiatus, coscinodiscus stellatis, coscinodiscus rothii, coscinodiscus perforatus var. cellulosus), which are mostly fragmented, and with their smaller representatives (coscinodiscus curvatulus, coscinodiscus doljensis, coscinodiscus sarmaticus, coscinodiscus rugulosus, paralia sulcata), giving better efficacy of d­02b sample as de like ma­4 (fig. 3, tab. 1). the relatively high content of opal­a (28%) and a small amount of quartz (5%) characterised sample ma­4 (tab. 2). in previous testing (liška et al., 2015) of samples (ma­4, mr­10, mr­10b, op­4, op­4a and pd­ 1) against tribolium castaneum (herbst) and rhyzopertha dominica (fab.) the highest efficacy (7 and 14 days after treatment) showed in sample ma­4, reaching t. castaneum mortality of 61.50% and 99%, respectively, and 25.50% and 34.0%, respectively against r. dominica. in addition, there were no statistical differences of mortality rates with the standard celatom® mn 51. according to ziaee et al. (2013) each diatom species could have its own mode of physical action, regarding the number and size of pores and distribution of striae and if it is greater, the insecticidal activity would be higher. the results on diatom morphometrics show that the most efficient diatomites consist of mid­ sized (<45 μm) coscinodiscus (coscinodiscus curvatulus and c. doljensis) with numerous smaller pores, and lancet shaped thalassionema nitzschioides that make up its active surface (fig. 3). this is in agreement with korunić (1998), that diatoms with discoid, flattened and linear body shapes better cover insect cuticle in relation to diatoms of cylindrical and round shapes. de particles can effectively adsorb epicuticular lipids from the cuticle surface of the treated insects (rohitha prasantha et al., 2015) and these phenomena may have a great effect on efficacy against insects. according to korunić et al. (2016), larger available active surfaces have a higher sorption capacity for the lipids and are more effective desiccants. in the experiment conducted by korunić & fields (2016) silica aerogel sipernat 50s with oil sorption of 3.23 ml/g dust was significantly more effective against sitophilus granarius (linnaeus) in comparison with other des with oil sorption from 1.13 to 1.96 ml/g dust. inert dusts ma­4 with oil sorption of 1.23 and celatom® mn 51 with oil sorption of 1.20 were equally effective against rice weevil sitophilus oryzae (linnaeus) and granary weevil, s. granarius. nevertheless, noticeable sponge spicules and silicoflagellates in samples may damage the digestive tract or breathing organ, also resulting in internal desiccation or suffocation of the insects (jackson & webley, 1994), which increases efficacy as well. sample mr-10 from banovina region has only 3 % opal-a, while sample mr-10b did not contain opaline silica. two samples from slavonia op­4 and op­4a contain small amounts of opal­c (tab. 2). based on the palaeontological results, the sporadic appearance of sponge spicules was noticed only in samples of op, which is in agreement with the results of murdmaas’ modified formula (tab. 5). these samples are partially modified by calcinations in the process of diagenesis. it is well known that during diagenesis siliceous deposits undergo mineralogical changes from non-crystalline biogenic silica (opal­a) to microcrystalline opal (opal­ct/c) to microcrystalline quartz (sio2) (williams et al., 1985; flörke et al., 1991; cady et al., 1996; lynne & campbell, 2004). micro­crystalline silica minerals (quartz) have been shown to be carcinogenic if inhaled. in addition, crystalline silica is classified as carcinogenic to humans by the international agency for research on cancer (iarc, 1997). des registered as g eologia c roatica i. galović et al.: croatian diatomites and their possible application as a natural insecticide 37 insecticides generally have less than 6% of quartz, like all analysed samples. however, the use of a proper dust mask, or the use of low crystalline silica de can protect against this health risk (desmarchelier & allen, 2000). very small amounts of opal-c were contained in samples pdk and d-01 (tab. 2). sample pdk appeared to have the best outcome on rw with inert dust less than 25 microns even after 5 days. this is in agreement with the fact that smaller particles of des (<45 µm) are significantly more effective than larger particles (korunić et al., 2011). species are mostly smaller than usual, but this is in accordance with their origin in the upwelling zone and with seasonal changes during the sarmatian, that limited their rapid growth in the blooming period (jurilj, 1957; galović & bajraktarević, 2006). nevertheless, sample pdk has a high content of carbonate minerals (calcite and aragonite), and a smaller amount of opal-a (12%), and quartz (3%) (tab. 2). despite lower concentrations of amorphous silica in samples ma­4 (28%) and pdk (12%), in combination with the increased content of smectite gives even better absorption properties. clays are also known as inert dusts like des (maceljski & korunić, 1972; banks & fields, 1995; subramanyam & roesli, 2000) that also influenced better adsorptions here. in almost all the analysed samples smectite is the dominant clay mineral. it has a 2:1 layer structure, with a large base exchange capacity (60–130 meq/100 g) and will readily adsorb cations such as h+, na+, ca2+, and mg2+ (weaver, 1989). interlayer cations are hydrated and replaceable, resulting in the swelling and dehydration characteristic for smectite (slovenec & bermanec, 2003). 6. conclusion sarmatian diatomites from medvednica mt. have different physical properties and efficacy on grain store insects. the analysed croatian diatomites have significantly lower concentration of sili ca in relation to the standard de. diatomites from borehole (d­01, d­02) have the highest amorphous silica component (41­ 50%) and small amounts of quartz (4­5%) which makes them suitable for commercial usage as de. they exhibit the highest efficacy on stored products insect rice weevil s. oryzae, together with inert dust from medvednica mt. (ma­4, pdk). based on palaeontolog­ ical results the most efficient analysed de consists of mid­sized planktonic coscinodiscus group of species where thalassionema nitzschioides dominate which is positively correlated with their absorption. even much smaller concentrations of amorphous sili ca in sample ma­4 (28%) and pdk (12%), but in combination with increased content of smectite gives even slightly better absorption property. the higher level of cao (9.63­36.29) in correlation with celatom® mn 51 (5.60) probably also increased efficacy. ca (ii) ions are known to improve flow rate in modified diatomite (bazhal et al., 1975). probably because of all mentioned para­ meters diatomite ma­4 and smaller fraction of pdk show no diffe­ rences of mortality rates with the standard celatom® mn 51. unfortunately, the small thicknesses of all prospective croatian diato mites (approx. 48 cm) and the slightly higher content of lead in ma­4 sample make them inadequate for classical usage as de (ma­4= 19.4. mg/kg, tab. 4). according to the standard sample celatom® mn 51 the allowed maximum pb concentration is 15 mg/kg. the content of quartz in the samples is 1­5 %. concerning insecticidal effects against the rice weevil, s. oryzae and taking into account the small thicknesses of all prospective croatian diatomite layers, there is the possibility of mixing these inert dusts with some other natural compounds, with other insecticide effects, to provide the same (or even higher) insecticidal level. acknowledgement financial support for this research was provided by the croatian science foundation (hrzz) through the scientific research project ip­11­2013­5570 (project leader prof. dr. sc. vlatka rozman): development of new natural insecticide formulations based on inert dusts and botanicals to replace synthetic, conventional insecticides, http://www.diacromixpest.eu/. the authors are grateful to snježana mihalić arbanas, faculty of mining, geology and petroleum engineering, for allowing using dolje borehole samples for the purpose of this research. we would like to thank to stjepan ćorić (gba, austria) and anonymous reviewer as well for their valuable comments and suggestions that improve the manuscript. references bajraktarević, z. (1984): the application of microforaminiferal association and nannofossils for biostratigraphic classification of the middle miocene of n. croatia.– acta geologica, 49/1, 1–34. bajraktarević, z., blašković, i. & polšak, a. (1986): tripoli­stratigrafski položaj, paleontološka i sedimentološka obilježja u području tethysa [tripolistratigraphic position, paleontologic and sedimentologic characteristics in tethys area – in croatian].– 11. kongr. geol. jugosl., 1986/2, 319–331, tara. banks, j. & fields, p. (1995): physical methods for insect control in stored grain ecosystems.– in: jayas, d.s., white, n.d.g. & muir, w.e. (eds.): stored grain ecosystems, marcel dekker, new york, 353–409. bazhal, i.g., vorona, l.g., leshchenko, a.v. & pereverzeva, i.n. (1975): effect of chemical modification of diatomite powder on their filtration qualities.– sov. prog. chem., 41, 91–92. boström, k., joensuu valdes, s. & riera, m. (1972): geochemical history of south atlantic ocean sediments since late cretaceous.– mar. geol. 12, 85–121. doi: 10.1016/0025­3227(72)90023­0 cady, s.l., wenk, h.r. & downing, k.h. (1996): hrtem of microcrystalline opal in chert and porcelanite from the monterey formation, california.– american mineralogist, 81, 1380–1395. doi: 10.2138/am­1996­11­1211 desmarchelier, k.m. & allen, s.e. (2000): diatomaceous earth: health, safety, environment, residues and regulatory issues.– in: jin, z., liang, q., liang, y., tan, x. & guan, l. (eds.): proceedings 7th international working conference on stored­product protection, beijing, pr china, 309–312. isbn 7536440987 dolley, t.p. & moyle, p.r. (2003): history and overview of the u.s. diatomite mining industry, with emphasis on the western united states.– us geological survey bulletin, 2209, e1­e8. ebeling, w. (1971): sorptive dusts for pest control.– annual review of entomology, 16(1), 123–158. doi: 10.1146/annurev.en.16.010171.001011 eberl, d.d. (2003): user’s guide to rockjock­a program for determination quantitative mineralogy from powder x­ray diffraction data.– u.s. geological survey, bulder, colorado, 46 p. fields, p. (2003): laboratory selection for resistance to diatomaceous earth.– in: credland, p.f. armitage, d.m., bell, c.h. cogan, p.m. & highley, e. (eds.): proceedings of the 8th international working conference on stored pro­ duct protection, york, uk, 776–778. fields, p.g. & muir, w.e. (1995): physical control.– in: subramanyam, b. & hagstrum, d.w (eds.): integrated pest management of insects in stored pro­ ducts, marcel­dekker inc., 195–222, new york. flörke, o.w., graetsch, h., martin, b., röller, k. & wirth, r. (1991): nomenclature of microcrystalline and non-crystalline silica minerals, based on structure and microstructure.– neues jahrbuch für mineralogie­abhandlungen, 163/1, 19–42. galović, i. (2001): silicous phytoplankton assemblage from sarmatian beds in the markuševec area (mt. medvednica, croatia).– acta botanica croatica, 60, 1–10. galović, i. & bajraktarević, z. (2006): sarmatian biostratigraphy of the mt. medvednica at zagreb based on siliceous microfossils (north croatia, central paratethys).– geologica carpathica, 57, 199–210. galović, i., halamić, j., rozman, v., korunić, z., liška, a., baličević, r. & lucić, p. (2015): dijatomiti u hrvatskoj: njihov potencijal kao prirodni insekticid. [diatomite in croatia: their potential as natural insecticide – in croatian].– in: horvat, m. & wacha, l. (eds.): 5th croatian geological congress, abstract book, 83–84. gorjanović­kramberger, d. (1908): geologijska pregledna karta kraljevine hrvatske – slavonije. tumač geologijskoj karti zagreb [geologic schematic map of the kingdom of croatia – slavonia. explanatory notes for the geologic map zagreb – in croatian].– nakl. kralj. zemalj. vlade, odjel za unutar. poslove, zagreb, 75 p. g eo lo gi a c ro at ic a geologia croatica 70/138 grizelj, a., peh, z., tibljaš, d., kovačić, m. & kurečić, t. (2017): mineralogical and geochemical characteristics of miocene pelitic sedimentary rocks from the south­western part of the pannonian basin system (croatia): implications for provenance studies.– geoscience frontiers, 8/1, 65–80. doi: org/10.1016/j. gsf.2015.11.009 grizelj, a., tibljaš, d. & kovačić, m. (2007): mineralogy and geochemistry of upper miocene pelitic sediments of zagorje basin (croatia): implication for evolution of pannonian basin.– geologica carpathica, 58/3, 263–276. hajós, m. (1986): stratigraphy of hungary’s miocene diatomaceous earth deposits.– geologica hungarica, series paleontologica, fasc., 49, 339 p. harwood, d.m. (2010): diatomite.– in: smol, j.p. & stoermer, e.f. (eds.): the diatoms: applications for the environmental and earth sciences, cambridge university press, 570–574. doi: 10.1017/cbo9780511763175.034 horvat, a. (2004): middle miocene siliceous algae of slovenia: paleontology, stratigraphy, paleoecology, paleobiogeography.– založba zrc, ljubljana, zrc sazu, 255 p. horváth, f. & royden, l.h. (1981): mechanism for the formation of the intra­ carpathian basins: a rewiev.– earth evolution sciences, 1, 307–316. iarc – international agency for research on cancer (1997): iarc monographs on the evaluation of carcinogenic risks to humans, silica, some silicates, coal dust and para­aramid fibrils, 68 iarc lyon. ibm corp. released (2013): ibm spss statistics for windows, version 22.0. armonk, ny: ibm corp. jackson, m.l. (1956): soil chemical analysis.– advanced course. medison. wisconsin, published by the author, 894 p. jackson, k. & webley, d. (1994): effects of dryacide on the physical properties of grains, pulses and oilseeds.– in: highley, e., wright, e.j., banks, h.j. & champ, b.r. (eds.): stored product protection, proceedings of the 6th international working conference on stored­product protection, 635–637. jones, j.b. & segnit, e.r. (1971): the nature of opal 1. nomenclature and constituent phases.– journal of the geological society of australia, 18, 1, 57–68. doi: 10.1080/00167617108728743 jurilj, a. (1957): dijatomeje sarmatskog mora okoline zagreba [diatoms from sarmatian sea in the surroundings of zagreb – in croatian].– in: ugrenović, a. (ed.): acta biologica i, jazu, 28, 5–134. kljajić, p. & perić, i. (2005). resistance of stored­product insects to insecticides.– pesticidi i fitomedicina, 20, 9–28. kochansky­devidé, v. & bajraktarević, z. (1981): miocen (baden i sarmat) najzapadnijeg ruba medvednice [miocene (badenian and sarmatian) of the westernmost margin of medvednica mt. – in croatian].– geološki vjesnik, 33, 43–48. zagreb. korunić, z. (1998): review diatomaceous earths, a group of natural insecticides.– journal of stored products research, 34/(2–3), 87–97. korunić, z. (2013): diatomaceous earths­natural insecticides.– pestic. phytomed., 28/2, 77–95. doi: 10.2298/pif1302077k korunić, z. & fields, p.g. (2016): relationship between insecticidal efficacy and oil absorption capacity of inert dusts against sitophilus spp.– indian journal of entomology, 78, 108–113. doi: 10.5958/0974­8172.2016.00031.6 korunić z., rozman, v., halamić, j., kalinović, i. & hamel, d. (2011): insecticide potential of diatomaceous earth from croatia.– integrated protection of stored products iobc/wprs bulletin, 69, 389–397. korunić, z., rozman, v., liška, a. & lucić, p. (2016): a review of natural insecticides based on diatomaceous earths.– agriculture, 22, 10–18. kováč, m., nagymarosy, a., holcova, k., hudáčková, n. & zlinska, a. (2001): paleogeography, paleoecology and eustacy: miocene 3rd order cycles of relative sea-level changes in the western carpathian-north pannonian basins.– acta geologica hungarica, 44, 1–45. liška, a., rozman, v., korunić, z., halamić, j., galović, i., lucić, p. & baličević, r. (2015): the potential of croatian diatomaceous earths as grain protectant against three stored-product insects.– integrated protection of stored products iobc­wprs bulletin, 111, 107–113. lynne, b.y. & campbell, k.a. (2004): morphologic and mineralogic transitions from opal-a to opal-ct in low-temperature siliceous sinter diagenesis, taupo volcanic zone, new zealand.– journal of sedimentary research, 74/4, 561–579. doi: 10.1306/011704740561 maceljski, m. & korunić, z. (1972): contribution to the knowledge of the mecha­ nism of acting of inert dusts against insects.– plant protection, 22, 117–118, 377–387. murdmaa, i., goedeev, v., kuzmina, t., turanskaya, n. & mikhailov, m. (1980): geochemistry of the japan trench sediments recovered on deep sea drilling project legs 56 and 57.– in: lee, m. & stout, l.n. (eds.): initial reports of the deep sea drilling project, 56–57, 1213–1232. doi:10.2973/dsdp. proc.5657.154.1980 pantocsek, j. (1903): beiträge zur kenntniss der fossilen bacillarien ungarns.– nagytapolcsany­pozsony, teil 1, 76 p., berlin. pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.– basin research, 13, 359–376. doi: 10.1046/j.0950­091x.2001.00155.x pavelić, d., avanić, r., kovačić, m., vrsaljko d. & miknić, m. (2003): an outline of the evolution of the croatian part of the pannonian basin system.– in: vlahović, i. & tišljar, j. (eds.): evolution of depositional environments from the paleozoic to the quaternary in the karst dinarides and the pannonian basin.– ias field trip guidebook, 155–161, zagreb. řeháková, z. (1977): marine planktonic diatom zones of the central paratethys mio­ cene and their correlation.– bull. geol. survey prague, 52, 147–157. rigaux, m., haubruge, e. & fields, p.g. (2001): mechanisms for tolerance to diatomaceous earth between strains of tribolium castaneum (coleoptera: tenebrionidae).– entomol. exp. appl., 101, 33–39. roetzel, r., ćorić, s., galović, i & rögl, f. (2006): early miocene (ottnanghian) coastal upwelling conditions along the southeastern scarp of the bohemian massif (parisdorf, lower austria, central paratethys).– beitr. paläont., 30, 387–413. rögl, f. (1996): stratigraphic correlation of the paratethys oligocene and miocene.– mitteilungen der gesellschaft der geologie und bergbaustudenten österreich, 41, 65–73. rögl, f. (1998): paleogeographic considerations for mediterranean and paratethys seaways (oligocene to miocene).– ann. naturhist. mus. wien, 99, ser. a, 279–310. rohitha prasantha, b.d., reichmuth, ch., adler c. & felgentreu, d. (2015): lipid adsorption of diatomaceous earths and increased water permeabi­ lity in the epicuticle layer of the cowpea weevil callosobruchus maculatus (f.) and the bean weevil acanthoscelides obtectus (say) (chrysomelidae).– journal of stored products research, 64, 36–41. doi: 10.1016/j.jspr.2015.08.003 rojht, h., horvat, a., athanassiou, c.g., vayias, b.j., tomanović, ž. & trdan, s. (2010): impact of geochemical composition of diatomaceous earth on its insecticidal activity against adults of sitophilus oryzae (l.) (coleoptera: curculionidae).– j. pest sci., 83, 429–436. doi: 10.1007/s10340­010­0313­6 rozman, v., korunić, z., halamić, j., liška, a., baličević, r., galović, i. & lucić, p. (2015): development of new natural insecticide formulations based on inert dusts and botanicals to replace synthetic, conventional insecticides-presentation of the research project of croatian science foundation.– in: korunić, j. (ed.): 27. seminar ddd i zupp, proccedings, 197–201, zagreb. rozman, v., korunić, z., halamić, j., liška, a., baličević, r., galović, i. & lucić, p. (2016): second year of research project of croatian science foundation on development of new formulations of natural insecticides – diacromixpest.– in: korunić, j. (ed.): 28. seminar ddd i zupp, proccedings, 265–269, zagreb. schrader h.j. & gersonde, r. (1978): diatoms and silicoflagellates.– in: za­in: zachariasse, w.j., riedel, w.r., sanfilippo, a., schmidt, r.r., brol­ sma, m.j., schrader, h.j., gersonde, r., drooger, m.m. & broekman, j.a. (eds.): micropaleontological counting methods and tehniques­an expercise on an eight metres section of the lower pliocene of capo rossello, si­ cily, utrecht micropaleontological bulletins, schotanus & jens, 17, 129–176. schütz, k., harzhauser, m., rögl, f., ćorić s. & galović, i. (2007): foraminiferen und phytoplankton aus dem unteren sarmatium des südlichen wiener beckens (petronell, niederösterreich).– jahrbuch der geologischen bundesanstalt wien, 147, 449–488. slovenec, d. & bermanec, v. (2003): sistematska minerlogija – mineralogija silikata [systematic mineralogy – mineralogy of silicates – in croatian].– udžbenici sveučilišta u zagrebu, 359 p., zagreb. starkey, h.c., blackmon, p.d. & hauff, p.l. (1984): the routine mineralogical analysis of clay­bearing samples.– u.s. geological survey bulletin, 1563, 31 p., washington. steininger, f.f., müller, c. & rögl, f. (1988): correlation of central parate­ thys, eastern paratethys, and mediterranean neogene stages.– in: royden, l.h. & horvath, i.f. (eds.) the pannonian basins. a study in basin evolution. aapg memoir, tulsa, 45, 79–87. subramanyam, b. & hagstrum, d.w. (1995). resistance measurement and management.– in: subramanyam, b. & hagstrum, d.w. (eds.): integrated management of insects in stored products, usa: marcel dekker inc., new york., 231–398. subramanyam, b. & roesli, r. (2000): inert dusts.– in: subramanyam, b. & hagstrum d.w. (eds): alternatives to pesticides in stored­product ipm, kluwer academic publishers, dordrecht, 321–373. doi: 10.1007/978­1­4615­ 4353­4_12 vayias, b.j., athanassiou, c.g., buchelos, c.t. (2008): evaluation of resistance development by tribolium confusum du val (coleoptera: tenebrionidae) to diatomaceous earth under laboratory selection.– j. stored prod res., 44, 162–168. doi: 10.1016/j.jspr.2007.09.001 viličić, d. (2003): fitoplankton u ekološkom sustavu mora [phytoplankton in marine ecological system – in croatian].– in: draganović, j.m. (ed): školska knjiga zagreb, 196 p., zagreb. vrsaljko, d. (1997): stratigrafija naslaga panona jugozapadnog dijela medvednice: [stratigraphy of panonian sediments of sw part of medvednica mt. – in croatian g eologia c roatica i. galović et al.: croatian diatomites and their possible application as a natural insecticide 39 with an english summary].– unpubl. master thesis, faculty of science, university of zagreb, 80 p. vrsaljko, d. (1999): the pannonian palaeoecology and biostratigraphy of mollusca from kostanjek­medvednica mt., croatia.– geologica croatica, 52, 9–27. doi: 10.4154/gc.1999.02 vrsaljko, d. (2003): biostratigrafija miocenskih naslaga žumberačkog i samoborskog gorja na temelju mekušaca [biostratigraphy of miocene deposits from žumberak and samobor mts. on the basis of molluscs – in croatian, with an english summary].– unpubl. phd thesis, faculty of science, university of zagreb, 147 p. vrsaljko, d., pavelić, d. & bajraktarević, z. (2005): stratigraphy and pa­ laeogeography of miocene deposits from the marginal area of žumberak mt. and samoborsko gorje mt. (northwestern croatia).– geologica croatica, 58, 133–150. doi: 10.4154/gc.2005.07 weaver, c.e. (1989): clays, muds, and shales.– elsevier amsterdam, 721 p. weaver, c.e. & pollard, l.d. (1973): the chemistry of clay minerals. developments in sedimentology 15. elsevier, amsterdam, 213 p. weiss, n.l. (1985): mineral processing handbook 3.– sme, new york, 9–29 p. williams, l.a., parks, g.a. & crerar, d.a. (1985): silica diagenesis, i. solubility controls.– journal of sedimentary petrology, 55/3, 301–311. ziaee, m., moharramipour, s. & dadkhahipour, k. (2013): effect of particle size of two iranian diatomaceous earth deposits and a commercial product on sitophilus granaries (col.: dryophthoridae).– journal of entomological society of iran, 33/2, 9–12. geologia croaticageologia croatica geologia croatica 67/2 137–143 2 figs. 4 tabs. zagreb 2014 ab stra ct as part of the project „geothermal map of the republic of croatia”, initiated in 2007, the broader regions of the cities of zagreb and karlovac were investigated (approx. 5500 km2) in order to determine information on the terrestrial heat flow density (thfd).the results presented here include computation of thfd at borehole locations and maps of thfd of the investigated area. it has been determined that thfd at the borehole locations varies over a wide range and values differ from those previously published. for most of the studied area, thfd is in accordance with the mean values for continental areas. two positive (zagreb and karlovac) and one negative (žumberak) geothermal value can be singled out. the map of thfd, as presented here, is different from the previously published maps and is considerably more precise. it is determined that hydrogeothermal sources in the investigated area are not associated with thfd in the above mentioned areas. keywords: geothermal map, heat flow density, heat conduction, croatia terrestrial heat flow density in the zagreb – karlovac area  miron kovačić croatian geological survey, sachsova 2, hr-10000 zagreb, croatia; (miron.kovacic@hgi-cgs.hr) doi: 10.4154/gc.2014.10 1. introduction in the last twenty years there has been increasing interest in the geothermal potential in croatia, as this has become an attractive energy resource. therefore the croatian geological survey (cgs) has been engaged over several years in research activities associated with these issues. within the project „geothermal map of the republic of croatia”, initiated in 2007, the area around the cities of zagreb and karlovac has been investigated (approx. 5500 km2) (fig. 1) in order to determine the geothermal characteristics. the heat conditions in the depths of our planet, in the earth crust and the upper mantle in particular, are manifested on the earth’s surface as the terrestrial heat flow density (thfd). thfd is the amount of heat energy per unit area rising from the earth’s interior towards its surface at a particular spot. computation of this parameter and its representation on a map is the usual approach to displaying the geothermal characteristics of a particular area. in order to compute thfd at a given location it is necessary to acquire more knowledge on the changes in heat transfer in a conductive regime through the geological formations – geothermal gradient (g), depth of formation at particular location, and coefficient of thermal conductivity of individual formations. this information is acquired by measurements, data processing and studying of materials from deep boreholes. laboratory studies were conducted in the laboratory of the cgs. results of thfd computations at the boreholes’ locations together with the map of thfd of the investigated area are presented here and compared with previously published data for this area. published data sources include: the heat flow map of europe (scale cca 1: 6,000,000) čermak and rybach (1979) which displays the territory of croatia; the geothermal atlas of europe (hurtig et al., 1992) shows a map of thfd (scale 1:2,500,000), including the territory of croatia; ravnik et al. (1995) presented the heat flow density map of slovenia of the area which partially includes the territory of croatia; the thfd map of croatia (scale geologia croatica 67/2geologia croatica 138 1:4,500,000) published that same year by jelić et al. (1995), while kovačić (1995) published his data concerning computations of thfd for locations of several boreholes in the investigated area. 2. methods methods applied in this research are briefly described separately for the individual geothermal parameters. geothermal gradient (g) temperatures in boreholes are determined by continuous tem perature well logging and measuring of „maximum temperature“ by maximum thermometer. data were used from the work of čubrić (1993) and from the ina-naftaplin database. where the conditions of temperature measurements are known, the temperature values are corrected. geothermal gradients (g) of lithostratigraphic units or their parts were calculated from the static temperatures in certain intervals using the following equation: 1 2 d −g = t t where t1–t2 is the temperature difference between the upper and lower interval limit while δ is the interval thickness in metres. thermal conductivity (k) thermal conductivity of sediments is determined according to the measurements of the rock samples from the boreholes and, less frequently, of the samples from the same stratigraphic units on the surface. measurements were carried out by a non-stationary method (quick thermal conductivity method) (sumikawa & arakawa, 1976; prelovšek & uran, 1984) in the laboratory of hgi-cgs. the instruments in use were mtp-4 (vtozd-fizika, university of ljublja na) and isomet 2104 (applied precision ltd, bratislava). according to the manufacturer’s data, the measurement accuracy is 10%. it is assumed that the rocks at depths are mostly figure 1: the geographic location of the investigated area. kovačić miron: terrestrial heat flow density in the zagreb – karlovac area geologia croatica 139 water saturated. to obtain the thermal characteristics of the samples similar to those of the in situ conditions, the samples were immersed in water for 20 days. according to the previously conducted measurements thermal conductivity is increased by up to 33 % when the porous rocks are saturated (kovačić, 2007). heat flow density for each interval with a linear increment of temperature (expressed geothermal gradient – g) and defined thermal conductivity (k) the interval heat flow density (qi) is calculated by the fourier equation (haenel et al., 1988): qi = k g terrestrial heat flow density (qt) is calculated by the interval method (powell et al., 1988) from the equation containing the intervals of heat flow density and the interval thickness (δ): q q t n n q n n n= = = = ∑ ∑ d d d d 1 1 1 , or, in a developed form: q q q q t n n n = + + + + ( ) ( ) ....( ) .... 1 1 2 2 1 2 d d d d d d a map of the terrestrial heat flow density is made by interpolation using the software package arcgis (esri). 3. geological setting the study area is located at the north-western margin of the extensional pannonian basin which evolved during the miotable 1: data of boreholes (drilled deposits: q – quaternary, pl – pliocene, m – miocene, k – cretaceous, t – triassic, pz – palaeozoic (uncertain age?); thfd – terrestrial heat flow density) boreholes designation on the map drilled deposits borehole depth (m) maximum temperature ( °c) thfd (mwm–2) dubranec 3 dub-3 q, pl, m 1603 67 54 dubravka-1 dka-1 q, pl, m 1090 64 79 jarun 1 jarun 1 q, pl, m 1635 63 61 karlovac 2 ka-2 q, pl, m, k, t 4145 152 74 karlovac 3 ka-3 q, pl, m, k, t 3523 139 104 klinička bolnica novi zagreb-1b kbnz-1b q, pl, m, t 1062 82 106 komarevo 1 kom 1 q, pl, m 917 44 54 lekenik-1 lek 1 q, pl, m 1820 78 56 lomnica 1 lom-1 q, pl, m, pz? 1936 95 67 lučanka-1 luč 1 q, pl, m 950 58 87 mladost-1 mla 1 q, pl, m 1057 77 94 nedjelja-1 n -1 q, pl, m, t 1311 64 75 odra 1 odra 1 q, pl, m 2503 102 55 podsused-2 pdte 2 q, m, t 530 30 88 petrinjka 1 petrinjka 1 q, pl, m 778 41 59 popović brdo popović brdo q, pl 144 19 52 precno 1 pč 1 q, pl, m, pz? 3430 122 56 resnik 1 re 1 q, pl, m 1836 76 56 resnik 2 re 2 q, pl, m 1752 83 57 samobor-2 sam 2 q, m, t 567 25 54 sava – 1 sava – 1 q, pl, m 1594 84 84 savica 1 sav 1 q, pl, m 2202 94 58 sisak 1 sisak 1 q, pl, m, pz? 2955 121 68 stupnik 1 stu 1 q, pl, m, t 832 61 96 sveta jana 1 sv. jana 1 q, pl, m, t 883 45 47 šalata termalna-1 šalt 1 q, pl, m 1038 52 69 zelina 1 ze 1 q, pl, m 1038 57 67 the thfd map of the investigated area is produced based on the aforementioned calculation (fig. 2). the thfd data from the territory of slovenia (rajver & ravnik, 2002) were taken into account for the purpose of drawing the map. geologia croatica 67/2geologia croatica 140 cene due to continental rifting processes (pavelić, 2001). the largest part of the terrain is a valley covered by quaternary deposits, in which the sava and kupa rivers flow (fig 1). between the river courses there is a minor hill – vukome ričke gorice – with outcrops of neogene sediments. mt. medvednica lies to the north. geologically, it is represented by a wide range of stratigraphic units dated from the palaeozoic to the quaternary. samoborsko gorje and the žum beračko gorje mts lie to the nw, where carbonate sediments of the middle and upper triassic age are predominant. these mountains take the form of hills on the west border of the investigated area where jurassic and cretaceous sedimentary rocks occur together with triassic rocks (basch, 1980; bu kovac et al., 1983; pikija, 1987; pleničar et al., 1976 and šikić et al., 1972). all boreholes mentioned in this work are located in the lowland part of the investigated area. they drilled through the following successions of sediments: 1. the pliocene and quaternary deposits which consist of various types of clastic sediments. the lower, pliocene part consists of predominantly lime-rich clays with intercalations of coal, sand and marl. in the quaternary part, the section is represented predominantly by alternations of gravel with sand and clay. the pliocene section of the deposits is devoid of any significant aquifer, while the quaternary part is characterized by high primary porosity and permeability, and contains significant quantities of fresh water. 2. tertiary – a) the lower and middle miocene deposits are represented by the following stratigraphic units: egerian, eggenburgian, ottnangian, karpatian, badenian and sarmatian. contact with the underlying rocks is unconformable. the lithology varies considerably and consists of marls, sandy marls, sandstone, breccia, breccia-conglomerates and lithothamnion limestone. these beds are characterized by primary and secondary porosity, and occasionally have very good permeability. also, sporadically they represent reservoirs for thermal water in the investigated area. b) pannonian the lower part of this unit consists of marl beds characterized by a high calcite content as well as clayey limestone. these deposits are impermeable. in the upper part, they are composed of marls which are sporadically silty, also impermeable and without primary porosity. c) pontian – in their lower part these deposits consist of calcare ous clays and marls with sporadic intercalations of sandsto ne. the upper part of these deposits is dominated by calcareous, somewhat sandy clays and marls with rare inter calations of fine-grained sandstone and coal. the deposits are impermefigure 2: terrestrial heat flow density map of investigated area. kovačić miron: terrestrial heat flow density in the zagreb – karlovac area geologia croatica 141 able, characterized by developed primary porosity and with no significant aquifers. 3. mesozoic – a) low permeability cretaceous carbonate rocks were drilled only in the boreholes ka-2 i ka-3. b) middle and upper triassic dolomite breccia, dolomites, and dolomite limestone, which were determined in the following boreholes: ka-2, ka-3, kbnz-1b, n -1, pdte – 2, stu – 1, st. jana – 1. the rocks are characterized by secondary porosity and high retention of thermal water. 4. metamorphic impermeable rocks drilled by the boreholes lom-1, pč – 1 and sisak – 1 are thought to be of palaeozic age (kovačić, 2010.) 4. results for the calculation of the thermal conductivity (tc) of the lithostratigraphic units previously published data were used (kovačić, 2007). these were updated by the numerous recent data necessary for correction of the tc of the lithostratigraphic units. measurements were completed on the rock samples from 11 boreholes and on the samples of equivalent stratigraphic units taken from the surface. in total, 1650 measurements on 155 samples were performed. multiple mea surements have been obtained by shifting the sensor and the subsequent statistical analysis has provided the mean tc values of individual samples. these were later used for the computation of the tc of lithostratigraphic units. calculation of thfd was performed for the locations of 27 boreholes in the investigated area. the calculation results and the boreholes’ attributes are displayed in table 1. 5. discussion thfd is very variable over the borehole locations in the area, ranging between 47 mwm-2 (sveta jana – 1) and 106 mwm-2 (kbnz-1b) (table 1). the mean value of thfd is 69.5 mwm-2. values above the average thfd were determined at 10 locations, and values below average at 17 locations. in the book heat flow map of europe (čermak and rybach, 1979) there is no data on thfd for a single location in the investigated area. this is also the case for the heat flow density map of slovenia (ravnik et al., 1995). in the geothermal atlas of europe, the thfd data can be observed for 4 boreholes (ravnik et al., 1992) (tab. 2). one of these is excluded from the calculation due to a lack of data. the thfd values for the boreholes dubranec – 3 table 2: comparison of calculated thfd boreholes designation on the map thfd mwm–2 ravnik, et al. (1992) kovačić (1995) new calculations dubranec-3 dub-3 67 – 54 karlovac-2 ka-2 60 ? – 74 karlovac-3 ka-3 60 ? – 104 klinička bolnica novi zagreb-1b kbnz-1b – 129 106 lučanka-1 luč-1 – 88 87 mladost-1 mla-1 – 115 94 nedjelja-1 n-1 – 68 75 resnik-1 re-1 – 58 56 samobor-2 sam-2 – 71 54 sava-1 sava-1 – – 84 stupnik-1 stu-1 97 119 96 table 3: global avarage terrestrial heat-flow density (after uyeda, 1988 and lowrie, 1997) continental mwm-2 oceanic mwm-2 global mwm-2 total heat output 1013 w authors 61 61 61 3.11 lee (1970) 53 62 59 3.01 chapman & pollack (1975) 61 87 77 3.96 langseth & anderson (1979) 53-61 100 81-84 4.15-4.30 davies (1980) 57 99 82 4.2 sclater et al. (1980) 65 101 87 4.42 lowrie (1997) table 4: springs of geothermal water in the investigated area (classification according to kovačić & perica, 1998) spring temperature °c classification aquifer mlakovac 17.5 subthermal triassic dolomite? sutinska vrela 20.0 sub thermal triassic dolomite toplica 18.8 sub thermal ? toplica (sveta jana) 24.1 hypothermal triassic dolomite topličica (stenjevec) 17.0 sub thermal ? topličica 14.3 sub thermal ? geologia croatica 67/2geologia croatica 142 and stupnik – 1 differ relatively slightly from the newly calculated data. for the borehole designated as karlovac the thfd is 60 mwm-2. in so far as the karlovac-2 borehole is in question the difference between the old and new computed values is relatively small, while for the karlovac-3 it is high and amounts to 44 mwm-2 (tab. 2). data acquired by continual temperature logging in ka-1 and ka-3 boreholes are indecisive. here, the most often used data are those obtained by maximum thermometer during the borehole testing, which may explain the variation in computation of the thfd. since the atlas is devoid of detailed information on calculations it is impossible to determine the causes for the aforementioned differences in calculation. jelić et al. (1995) do not present data for the thfd of the borehole locations. in the published work, the calculated values of thfd on the borehole locations are mostly somewhat higher than the newly calculated ones (tab. 2). the varied results are due to different mode of calculation. in kovačić (1995) the calculation is made only for sedimentary rocks older than pliocene and quaternary ages while the new calculation included all sediments from the bottom of the borehole to the surface. from this, correction of the tc of the stratigraphic unit has been calculated. over most of the investigated area the thfd values range from 50 to 70 mwm-2 (fig. 2), and two zones of increased values are clearly visible. one of these is in the southern part of zagreb extending northwest towards slovenia. here the thfd ranges from 70 to 106 mwm-2. another one, with thfd values ranging from 70 to 104 mwm-2 extends to the area northeast of karlovac. the thfd value and the extension of this zone are questionable due to both the aforementioned inconclusive data concerning the temperatures measured in ka-1 and ka-3 boreholes and the fact that only two boreholes exist in this area. in the area of samobor and the žumberak mts. there is a zone with thfd less than 50 mwm-2. when compared with data from all over the world, the thfd values from most of the investigated area show the average values for the continents (uyeda, 1988) (tab. 3). due to the close relations of the thfd in the investigated and surrounding areas (hurtig et al., 1992; rajver & ravnik, 2002), the zones of the increased thfd can be called the zagreb and karlovac positive geothermal anomaly. by the same token, the area with the smallest thfd can be called the žumberak negative anomaly. because both the karlovac and žumberak geothermal anomalies occupy relatively small areas we can call them local while the zagreb anomaly which extends towards slovenia (krško) can be defined as regional. comparison with hitherto published maps of the thfd comprising the investigated area is difficult because the latter are, represented on a much greater scale. on the heat flow map of europe (čermak & rybach, 1979) thfd in the investigated area ranges between 60 and 70 mwm-2. on another map of thfd by hurtig et al., (1992) the values range between 50 and 80 mwm-2. on the heat flow density map of slovenia (ravnik et al., 1995) the thfd values are in 40– 80 mwm-2 range, whereas on the one by jelić et al. (1995) they fall in the 50 – 85 mwm-2 range. on both maps the highest values of thfd are in the area of zagreb, while in the area of karlovac the thfd is considerably lower with regard to the value determined by this research. in the investigated area there are 6 springs of geothermal water (fig. 2, tab. 4). the water temperature at the springs is relatively low, being higher with regard to mean annual temperature characteristic of the spring areas by only 4 to 14 0c. two springs are located in the area of the zagreb positive anomaly and two in the area of the žumberak negative anomaly. therefore it can be concluded that the spring locations and thfd are not related at these locations. 6. conclusions thfd in the boreholes in the wider area of the cities of zagreb and karlovac (cca 5500 km2) is very variable ranging between 47 and 106 mwm-2. over most of the investigated area thfd ranges between 50 and 70 mwm-2 which is in accordance with the average values for the continental areas. two positive (zagreb and karlovac) geothermal anomalies and a single negative (žumberak) geothermal anomaly depart from the above values. according to their magnitude it can be said that the karlovac and žumberak anomalies are local whereas the zagreb anomaly is regional as it extends toward the slovenian territory. based on the magnitudes and spatial distribution of thfd in the investigated area it can be concluded that a considerable geothermal potential exists in the zone of the positive zagreb and karlovac geothermal anomalies. the map of thfd as represented here differs with regard to maps hitherto published and is considerably more precise due to the scale and much greater number of points used in calculation. the location and temperature of water in six geothermal springs in the investigated area are not associated with thfd in that area. acknowledgement many thanks to tonči grgasović, radovan avanić and davor vrsaljko for their help in sampling the characteristic portions of the lithostratigraphic units in the area of samobor and žumberak mts. as well as to staša borović for measurements of tc on the surface rock samples. the investigation was supported by the ministry of science, education and sports of the republic of croatia. references basch, o. (1980): osnovna geološka karta sfrj 1:100000, list ivanićgrad l33-81[basic geological map of sfry 1:100000, sheet iva­ nić-grad – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. bukovac, j., poljak, m., šušnjar, m. & čakalo, m. (1983): osnovna geološka karta sfrj 1:100000, list černomelj l33-91 [basic geological map of sfry 1:100000, černomelj sheet – in croatian].– geološki zavod, zagreb i geološki zavod, ljubljana, savezni geološki zavod, beograd. kovačić miron: terrestrial heat flow density in the zagreb – karlovac area geologia croatica 143 čermak, v. & rybach, l. (eds.) (1979): heat flow map of europe.– springer-verlag, berlin/heidelberg/new york, 328 pp. + 1 map. čubrić, s. (1993): power and energy of geothermal reservoirs in the republic of croatia.– nafta, 44, 459–470, zagreb. haenel, r., rybach, l. & stegena, l. (1998): fundamentals of geothermics.– in: haenel, r., rybach, l. & stegena, l. (eds.): handbook of terrestrial heat-flow density determination, kluwer academic publishers, dordrecht/boston/london, 9–57. hurtig, e., èermak, v., haenel, r. & zui, v. (1992): geothermal atlas of europe.– geoforschungszentrum potsdam. pub. no. 1., 156 pp. + 25 maps. jelić, k., kevrić, i. & krasić, o. (1995): temperature i toplinski tok u tlu hrvatske [temperature and heat flux in the croatian ter­ ritory – in croatian].– in: vlahović, i., velić, i. & šparica, m. (eds.): 1st croatian geological congress, opatija, october 18– 21, 1995., proceedings 1, zagreb, 245–249. kovačić, m. (1995): prilog poznavanju gustoće površinskog toplinskog toka u širem području zagreba [contribution to knowledge on terrestrial heat-flow density in the greater area of zagreb – in croatian].– in: vlahović, i., velić, i. & šparica, m. (eds.): 1st croatian geological congress, opatija, october 18–21, 1995., proceedings 1, zagreb, 303–306. kovačić m. & perica r. (1998): stupanj korištenja geotermalnih voda u republici hrvatskoj [the degree of geothermal water utilization in the republic of croatia].– hrvatske vode, 25, 355–361, zagreb. kovačić, m. (2007): odnosi toplinske provodljivosti stratigrafskih jedi nica iz šireg područja zagreba [relations between the thermal conductivity of the stratigraphic units in the wider area of zagreb – in croatian].– rudarsko-geološko-naftni zbornik, 19, 27–33. kovačić m. (2010): history of exploration and exploitation of geothermal energy in the zagreb geothermal area (croatia).– proceedings world geothermal congress 2010. bali, indonesi: iga, 2010, 1–5. lowrie, w., 1997: fundamentals of geophysics.– cambridge university press, 368 p. pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.– basin research, 13, 359–376. pleničar,m., premru, u. & herak, m. (1976): osnovna geo loška karta sfrj 1:100000, list novo mesto l33-79 [basic geologi­ cal map of sfry 1:100000, novo mesto sheet – in croatian].– geološki zavod, ljubljana, zvezni geološki zavod, beograd. powell, w.,g., chapman, d., s., balling, n. & beck, a.,e. (1998): continental heat-flow density.– in: haenel, r., rybach, l. & stegena, l. (eds.): handbook of terrestrial heat-flow den sity determination, kluwer academic publishers, dordrecht/ boston/london, 167–222. pikija, m. (1987): osnovna geološka karta sfrj 1:100000, list sisak l33-93 [basic geological map of sfry 1:100000, sisak sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. prelovšek, p. & uran, b. (1984): generalised hot wire method for thermal conductivity measurements.– j. phys. e. sci. instrum., 17, 674–677. rajver, d. & ravnik, d. (2002): geotermična slika slovenije-razširjena baza podatkov in izboljšane geotermalne karte [geothermal picture slovenia-extended database and improved geothermal maps – in slovenian].– geologija, 45, 519–524, ljubljana. ravnik, d., kolbah, s., jelić, k., milivojević, m., miošić, n, tonić, s. & rajver, d. (1992): yugoslavija.– in: hurtig, e., čermak, v., haenel, r. and zui, v. (eds.): geothermal atlas of europe. geoforschungszentrum postdam. pub., 1, 102– 104, 152–153. ravnik, d., rajver, d., poljak, m. & živčić, m. (1995): overview of the geothermal field of slovenia in the area between the alps, the dinarides and the pannonian basin.– tectonophysics, 250, 135–149. sumikawa, s. & arakawa, y. (1976): quick thermal conductivity meter.– instrumentation and automation (japan), 4, 60–68. šikić, k., basch, o. & šimunić, an. (1972): osnovna geološka karta sfrj 1:100000, list zagreb l33-80 [basic geological map of sfry 1:100000, zagreb sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. uyeda, s. (1988): geodynamics.– in: haenel, r., rybach, l. & stegena, l. (eds.): handbook of terrestrial heat-flow density determination, kluwer academic publishers, dordrecht/boston/ lon don, 317–351. manuscript received november 27, 2013 revised manuscript accepted april 11, 2014 available online june 17, 2014 2019 | 72/2 | 137–14 4 | 5 figs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the central part of the apulian foreland, including the murge sector and its adriatic offshore area (southern italy; fig. 1a), have been generally considered practically free from significant levels of seismicity (fig. 1b). however, this opinion is contradicted by several data, including historical documentation, instrumental observations (del gaudio et al., 2005; pierri et al., 2013; locati et al., 2016; rovida et al., 2016), seismically-induced soft-sediment deformation structures in quaternary sediments (moretti, 2000; moretti et al., 2002), and large boulder accumulations resulting from tsunami events (mastronuzzi & sansò, 2004; fig. 1a). such evidence of strong earthquakes suggest that the activity of local minor tectonic structures could have been “masked” by that of major seismogenic structures located in neighbouring regions (e.g., del gaudio et al., 2005, 2007). these include the apennine and dinarides-albanideshellenides orogens (figs. 1a-c), and the structures responsible for major historical earthquakes of the northern puglia region (e.g., mw 6.7 events of 1627 and 1646, and mw 6.3 of 1731; rovida et al., 2016), the exact location of which is still a matter for debate (e.g., del gaudio et al., 2007) and, in some studies, related to the mattinata-gondola fault system (e.g., patacca & scandone, 2004; tondi et al., 2005; figs. 1a,b). additional support for this conjecture derives from the recent march 23rd 2018 earthquake, which occurred in the southeast murge adriatic offshore, at the transition between the apulian foreland and the dinarides-albanides foredeep domains. according to the data reported for this event by ingv (istituto nazionale di geofisica e vulcanologia) on the italian national earthquake centre website (http://cnt.rm.ingv.it/), this event (see http://cnt.rm.ingv.it/event/18504011) occurred at the hypocentral depth of 26–30 km, was characterized by an estimated moment magnitude of mw 3.7, a scalar seismic moment mo of 4.74∙ 1014 n∙m and a fault plane solution with two nodal in search of the seismogenic source of the march 23rd 2018 earthquake (mw 3.7) near brindisi (puglia, southern italy) vincenzo festa1,*, francesco de giosa2, vincenzo del gaudio1, massimo moretti1 and pierpaolo pierri1 1 università degli studi di bari “aldo moro”, dipartimento di scienze della terra e geoambientali, via e. orabona, 4, i-70125 bari, italy; (*corresponding author: vincenzo.festa@uniba.it) 2 environmental surveys s.r.l. (ensu) – spin-off dell’università degli studi di bari “aldo moro”, via a. de gasperi, i-74123 taranto, italy doi: 10.4154/gc.2019.10 abstract the portion of the southern adriatic sea, adjacent to the murge area (apulian foreland, southern italy), is considered mainly aseismic. the recent march 23rd 2018 earthquake (mw 3.7), occurred near brindisi (puglia region), giving us occasion to reconsider data coming from different sources (instrumentally-recorded, historically-documented and palaeoseismologically-interpreted earthquakes), that suggest some moderate seismic shocks in this portion of the adriatic sea. the present study, based on the re-interpretation of public domain seismic profiles and exploration well logs available in the videpi project, has been focused on the recognition of faults with quaternary activity in the epicentral area. a s-dipping fault, with a main dip-slip component of movement, is suggested to be the seismogenic source. its geometry is consistent with the fault plane solution and the depth of the hypocenter calculated by the ingv (istituto nazionale di geofisica e vulcanologia). planes, one approximately e-w oriented, dipping towards the south (with strike, dip and rake of 81°, 87° and 124°, respectively) and the other approximately n-s oriented, dipping towards the west (with strike, dip and rake of 176°, 34° and 6°, respectively; fig. 1d). this was the strongest shock recorded in the central puglia region since 1980, when local seismicity started to be more accurately monitored thanks to the integration of the national seismic network, managed by the ingv, with the regional instrumental network, managed by the university of bari seismological observatory. in order to identify the seismogenic source and resolve the fault plane ambiguity, the present study investigates the quaternary activity of faults in the epicentral area (fig. 1d) by the interpretation of public domain seismic profiles and exploration well logs available in the videpi project (videpi, 2015). the main results are discussed with data coming from different sources (e.g., palaeoseismicity, historical documentation, instrumentally recorded earthquakes). therefore, the approach adopted in the present research study would be useful to analyze the seismicity of foreland/cratonic areas. although these are generally considered to be practically aseismic, several studies suggest that tectonic stress can be transmitted far from the active plate boundaries, causing rare, although sometimes strong, seismic events (e.g., johnston & kanter, 1990; calais et al., 2016, and references therein). 2. geological setting the apulian foreland, which practically corresponds to the puglia region (southern italy), represents the plio-pleistocene foreland of the apennine (westward) and the dinarides-albanideshellenide orogens (eastward); its adriatic offshore almost coincides to the dinarides-albanides foredeep domain (e.g., ricchetti et al., 1988; figs. 1a,c). the apulian foreland continenarticle history: manuscript received october 26, 2018 revised manuscript accepted february 21, 2019 available online june 3, 2019 keywords: earthquake, seismogenic fault, murge adriatic offshore, apulian foreland, palaeoseismicity g eo lo gi a c ro at ic a geologia croatica 72/2138 tal crust, showing a thickness of about 25–30 km (del gaudio et al., 2001; amato et al., 2014; de lorenzo et al., 2014), is characterized, in its uppermost part, by sedimentary cover about 7 km thick overlying a variscan basement (fig. 1c), the latter being exposed in the calabrian massifs (festa et al., 2010). the sedimentary cover basically consists, from the bottom, of permotriassic red beds (verrucano fm), a triassic anhydrite-dolomite succession (burano fm), and jurassic – cretaceous limestones belonging to the apulia platform (e.g., ricchetti et al., 1988; fig. 1c). the latter extensively crops out in the puglia region, where a middle jurassic – upper cretaceous inner platform carbonate succession shows a thickness of about 4 km (ciaranfi et al., 1988; spalluto et al., 2005). locally, in the eastern puglia region, outcropping marginal pelagic carbonate sediments figure 1. (a) sketch to show major tectonic boundaries and fault systems of the southern adriatic sea and its adjacent areas (modified after ricchetti et al., 1988). the main fault systems, traced for the apulian foreland and its adriatic offshore, are: mg – mattinata-gondola fault system (after de alteriis, 1995; chilovi et al., 2000); ms – monopoli system (after morelli, 2002). localities characterized by seismically-induced deformation structures in soft quaternary sediments, from moretti (2000) and moretti et al. (2002). coast line with local accumulations of large boulders, after mastronuzzi & sansò (2004). (b) geographical epicentral distribution of earthquakes of m≥3.0 located in the apulian foreland and surrounding regions, reported in castello et al. (2006), for the period 1981 – 2002, and in the italian national earthquake centre website (http://cnt.rm.ingv.it/), from 1981 to the date of the examined earthquake (2018.03.23); circle size is proportional to earthquake magnitude and colors indicate the hypocentral depths, according to the legend; the area of the panel is the same of that of figure 1a. (c) schematic geological cross section from the front of the apennines to the front of the albanides (redrawn and simplified after fantoni & franciosi, 2010). (d) map of the southeast murge adriatic offshore; the location of the rosaria mare exploration well and of the seismic profiles (from videpi, 2015) is indicated; bathimetry after emodnet (2017); coastline after puglia.con (2015). epicenter location and earthquake parameters at side of the fault plane solution of the march 23rd 2018 seismic event, after invg (http://cnt.rm.ingv.it/event/18504011). (e) map of the top of cretaceous-tertiary limestones in the southeast murge adriatic offshore; the upper cretaceous rosaria mare intra-platform basin, delimited by extensional faults, can be appreciated (modified after nicolai & gambini, 2007); the area of the panel is the same of that of figure 1d. g eologia c roatica festa et al.: in search of the seismogenic source of the march 23rd 2018 earthquake (mw 3.7) near brindisi (puglia, southern italy) 139 record the lateral transition to the basinal domain (e.g., borgomano, 2000; brandano et al., 2010; morsilli et al., 2017), i.e., the mesozoic – paleogene adriatic-ionian basin (fig. 1c), which roughly occupied the position of the present-day adriatic sea (zappaterra, 1994). the top of this basin is dominated by pelagic carbonates belonging to the cretaceous – paleogene scaglia-type deposits (nicolai & gambini, 2007; fantoni & franciosi, 2010); similar deposits, however, locally filled upper cretaceous intra-platform basins (de’ dominicis & mazzoldi, 1987; nicolai & gambini, 2007; mastrogiacomo et al., 2012; festa et al., 2018) bounded by normal faults (e.g., nicolai & gambini, 2007). in this regard, the margins of the rosaria mare intra-platform basin (located in the epicentral area) are geometrically controlled by upper cretaceous normal faults (nicolai & gambini, 2007; fig. 1e). neogene and quaternary carbonate – terrigenous deposits locally and discordantly overlie the mesozoic and paleogene sediments (ciaranfi et al., 1988; tropeano & sabato, 2000; tropeano et al., 2004). these deposits show an increasing thickness eastwards into the dinarides-albanides foredeep (fig. 1c); here, they include the miocene bisciaro fm, overlying the pelagic carbonates of the adriatic-ionian basin (i.e. the cretaceous – paleogene scaglia-type deposits; nicolai & gambini, 2007; fantoni & franciosi, 2010). the major seismogenic structure dissecting the apulian foreland, as well as its adjacent dinarides-albanides foredeep, is the w-e striking mattinata-gondola fault system (e.g., de alteriis, 1995; chilovi et al., 2000; kastelic et al., 2013; fig. 1a). it was able to produce seismic shocks larger than mw 5 (see the shallow gondola fault zone, in diss working group, 2018). south of this fault zone, the murge area (fig. 1a) is mainly affected by extensional faults striking nw-se to w-e, towards the adriatic coastline, and dipping from the ne to n, respectively (pieri et al., 1997; tropeano et al., 1997). the low energy seismicity of the murge area has been related to the activity of these faults (del gaudio et al., 2005), i.e., structures inherited since the cretaceous (festa, 2003). their possible continuation in the adriatic offshore have been considered by morelli (2002), especially concerning the monopoli system of faults, that were the origin of the monte giove structural high within the pre-quaternary bedrock (fig. 1a). 3. dataset and methods to reach the objective of the present research paper, in addition to parameters of the march 23rd 2018 earthquake available on the institutional website of the invg (http://cnt.rm.ingv.it/ event/18504011; figure 1d), the following public datasets, covering the epicentral area, were used: i) sea floor bathymetry (fig. 1d; emodnet, 2017); ii) adriatic coastline of the southeast murge (fig. 1d; puglia. con, 2015); iii) seismic profiles (stack version) d82-595, 81-cla-06, 81-cla-11, d461, d462, d463, d464, d465, d448, d449 and d450 (fig. 1d, for location; videpi, 2015); iv) rosaria mare 1 well (fig. 1d, for location; videpi, 2015). the georeferenced traces of the available seismic lines were uploaded in an esri arcgis software project, and were interpreted to identify georeferenced faults affecting the quaternary unit. the mean interval velocity of 1800 m/sec (p-wave) for the drilled quaternary deposits was used according to bally et al. (1986) and morelli (2002). xy geographic coordinates and the depth z, calculated in metres below sea level from two-waytime data, were obtained for a relevant number of points of the base of the quaternary unit reflection; therefore, a .shp file containing xyz values of each point was created in esri arcmap software. to fill the gap of data missing between seismic profiles, the .shp file data were interpolated by “kriging” (a geostatistical “gridding” method), using the default linear variogram and smoothing interpolator (e.g., sarma, 2009). thus, an esri grid file was created to construct the contour map of the base of the quaternary unit. 4. results according to the 1850 m deep stratigraphic log of the rosaria mare 1 well (fig. 2), the pre-quaternary bedrock of the investigated area consists, from the bottom, of thick cenomanian – lower senonian limestones, dolostones and marly limestones belonging to the apulia platform; they are topped by a thin lithostratigraphic unit represented by upper senonian – oligocene basinal marly limestones, marls and limestones belonging to the scaglia fm; aquitanian – tortonian marls and limestones, belonging to the bisciaro fm, follow toward the top. the quaternary unit, dominated by clays and also consisting of sandy gravels, is characterized by continuous reflections generally prograding toward the ne (fig. 2), namely into the deepest part of the southern adriatic sea basin. the base of this unit exhibits a continuous high amplitude reflection, that has been recognized and traced with gentle dip angles in the whole investigated area (figs. 2, 3a-d). however, in several seismic profiles, the base of the quaternary unit is locally deformed by high-angle generally southand north-dipping faults (dip-angle in the range of 60°–80°, obtained after time-to-depth conversion) having a normal component of movement (figs. 2, 3a-d). tips of these faults are mostly interpreted within the quaternary unit (left sector of fig. 2, and figs. 3a,c). besides, fault terminations have been locally observed within the bedrock of the quaternary unit, which is in this case gently folded due to the upward propagation of the underlying blind fault (right sector of fig. 2, and figs. 3b,d). unfortunately, due to the general low resolution of the available unmigrated seismic profiles, it was not always possible to recognize whether the quaternary unit succession is deformed by faulting also in its uppermost part, though locally it has been clearly observed that some faults deform the whole quaternary unit (fig. 3a). the interpolation of fault data interpreted from available seismic sections allowed us to trace and delineate two main faults about 40 km long in map view (fig. 4), which have been active during the quaternary. the fault occupying the northern sector of the study area shows a gentle arcuate shape, with convexity towards the south, and a general w-e strike (fig. 4). this highangle, and s-dipping fault (right sector of fig. 2, and figs. 3a,b, 4) is the southern boundary fault of the monte giove structural high (fig. 1a), i.e. the northern boundary fault of the upper cretaceous rosaria mare intra-platform basin (fig. 1e). southward, another high-angle fault generally strikes wnw-ese and dips to the nne (fig. 4), as an antithetic to the s-dipping fault (left sector of fig. 2, and figs. 3c,d, 4). the vertical offset of the base of the quaternary unit, estimated as 200 m maximum, is slightly greater along the s-dipping fault (figs. 2, 3a-d). as shown by the structure contour map of the base of the quaternary unit in figure 4, both faults give rise to a graben-type structure. within this quaternary graben-type structure, the highamplitude reflection at the base of the quaternary unit reaches a g eo lo gi a c ro at ic a geologia croatica 72/2140 maximum depth at about 0.8 sec (two way times – twt), or about 1000 m below sea level. on the graben shoulders, i.e. in the footwall of the two boundary faults, a minimum depth at about 0.3 sec (twt), namely 200 m below sea level, has been calculated (fig. 4). in the central part of the graben-type structure, the geometry of the base quaternary structure contours indicates the presence of a ne-sw striking intra-basin high, culminating at about 450 m below sea level. this high is also bounded by two roughly e-w striking antithetic faults (fig. 4) both showing a dip-slip displacement component, however, accommodating a minor offset of the base of the quaternary horizon (central sector of fig. 2). 5. discussion according to the results obtained from the interpretation of seismic profiles used in this study, the s-dipping fault, located at the northern margin of the rosaria mare basin, is found as the only one geometrically coherent with the steeply (87°) s-dipping nodal plane in the fault plane solution of the march 23rd 2018 earthquake (fig. 1d). the rupture size of the march 23rd 2018 earthquake source cannot be reliably estimated through empirical relationships taking only into account the mo of 4.74 ∙ 1014 n ∙ m of this event. in fact, such relations (e.g., wells & coppersmith, 1994; wang & ou, 1998; stock & smith, 2000) were calibrated for events with mo larger by orders of magnitude than the march 23rd 2018 earthquake, but it can be estimated that, in any case, the rupture of this earthquake source was sub-kilometric. although this fault clearly shows a dip-slip component of displacement of the base of the quaternary stratigraphic horizon (figs. 2, 3a-d), a combined reverse and dextral movement is indicated by the fault plane solution in figure 1d. a right transtensional kinematic during the quaternary, along the s-dipping fault may be invoked, suggested by the coeval prevailingly sw-ne to ssw-nne directed maximum horizontal extension both in the onshore vicinity of the fault (di bucci et al., 2011) and on the regional scale (di bucci et al., 2006; fracassi & valensise, 2007). since a relatively greater dip-slip component of quaternary displacement can be observed on this s-dipping fault than on the nnedipping one (e.g., figs. 2, 3a-d, 4), the graben-type structure bordered by these two faults (fig. 4) could also be interpreted as a negative flower structure (fig. 5), in which, according to the geometric features of flower structures (e.g., harding, 1985), the s-dipping fault would play the role of the main fault rooted at depth into a near-vertical fault plane, whereas the nne-dipping one would be a subsidiary and antithetic fault (fig. 5). regional geological literature revealed that the structural style of the apulia foreland and its adjacent foredeep domains is characterized by crustal-scale faults (e.g., doglioni et al., 1994; pieri et al., 1997; tropeano et al., 1997; merlini et al., 2000; argnani et al., 2001; finetti & del ben, 2005; butler, 2009; scisciani & calamita, 2009; fantoni & franciosi, 2010). therefore, in the block-diagram of figure 5. a deep geometric reconstruction of the s-dipping fault, as well as the nne-dipping fault, has been attempted to a depth of 25–30 km, namely the depth of the hypocenter (fig. 1d). coherently with the geometry of the s-dipping fault, this reconstruction shows that the hypocenter roughly lies on the fault plane, which makes the association fi gu re 2 . s ei sm ic li ne d 46 3 w ith in te rp re ta tio n of th e ba se o f q ua te rn ar y ho riz on a nd q ua te rn ar y ac tiv e fa ul ts (s ee f ig . 1 d fo r t he li ne lo ca tio n) . g eologia c roatica festa et al.: in search of the seismogenic source of the march 23rd 2018 earthquake (mw 3.7) near brindisi (puglia, southern italy) 141 of the earthquake to the activity of this fault plausible. in this regard, the reactivation at depth of a preexisting w-e striking fault, that geometrically controlled the northern margin of the upper cretaceous rosaria mare intra-platform basin (nicolai & gambini, 2007; fig. 1e), and was also active during the quaternary, can be considered to be in agreement with di bucci et al. (2006). these authors interpreted the e-w striking, right-lateral seismogenic faults in the apulian foreland as inherited and figure 3. (a) and (b) interpretation of the base of quaternary unit, and of the s-dipping quaternary fault on the seismic lines d450 and d464, respectively (legend as in fig. 2; see fig. 1d for their location). (c) and (d) interpretation of the base of quaternary unit, and of the nne-dipping quaternary fault on the seismic lines d462 and d465, respectively (legend as in fig. 2; see fig. 1d for their location). g eo lo gi a c ro at ic a geologia croatica 72/2142 reactivated discontinuities. as a result, the epicenter occurred at a minimum distance of about 15 km south of the trace of the s-dipping fault (figs. 1d, 4, 5). the hypocenter depth is comparable to that of both the moho beneath the apulian foreland (25–30 km; del gaudio et al., 2001; amato et al., 2014; de lorenzo et al., 2014) and the seismogenic layer locally identified below the northern apulian foreland (about 26 km; chiarabba et al., 2005). this indicates, for the study area, a relative high strength for the deeper lower crust, which is thus subject to brittle failure under tectonic stress. from a palaeo-seismic point of view, seismically-induced deformation structures of soft-sediment have been reported in the youngest deposits cropping out along the adriatic coastal sectors (late pleistocene marine terraced deposits). liquefaction and/or fluidization effects have been analyzed in the bari (moretti et al., 2002) and brindisi areas (moretti, 2000; fig. 1a). they involve deposits of back-shore and interdune environments containing sands with a high susceptibility to liquefaction (moretti et al., 2016). despite the limitations of the actual palaeoseismic significance of seismites (moretti & van loon, 2014), these traces of past earthquakes record seismic events with m > 5 that occurred within epicentral distances of about 100 km, as shown by empirical relationships for southern italy (galli, 2000) and in the adjacent greek seismic zones (papadopoulos & lefkopoulos, 1993). in other words, the known seismicallyinduced soft-sediment deformation structures in the late pleistocene deposits in the brindisi and bari areas, at 45 and 75 km from the epicenter, respectively (fig. 1a), imply that some faults of the central apulian foreland are able to produce seismic shocks with moderateto high-magnitude. finally, the boulder accumulations that are reported along the coastline in the neighbourhood of the epicenter and which are interpreted as formed by tsunami events (mastronuzzi & sansò, 2004; fig. 1a) may be also the result of seismicity in the adriatic offshore of the murge area. 6. concluding remarks in the epicentral area of the recent march 23rd 2018 earthquake (mw 3.7) which occurred near brindisi, in the adriatic offshore of the southeastern murge, interpretation of seismic profiles, available in the videpi project, supports the following conclusions: (i) two main high-angle faults, about 40 km in length, and active during the quaternary, have been recognized on the margins of a graben-like structure, that corresponds with the upper cretaceous rosaria mare intra-platform basin: the northern one is the e-w to nw-se striking and s-dipping fault; the southern one is a nw-se striking and nne-dipping fault; (ii) both faults mostly show dip-slip movement (even though a right transtensional kinematic cannot be excluded), and gave rise to a quaternary negative flower structure: the s-dipping fault (showing vertical offset of the base of the quaternary unit up to 200 m) and the nne-dipping one (showing slightly lower offset) represent the main and the subsidiary faults, respectively; figure 4. structure contour map of the base quaternary horizon of southeast murge adriatic offshore area (depth is expressed in metres below the sea level). g eologia c roatica festa et al.: in search of the seismogenic source of the march 23rd 2018 earthquake (mw 3.7) near brindisi (puglia, southern italy) 143 (iii) the geometric coherence between the plane solution of the earthquake and the s-dipping fault, suggests that this structure, likely inherited from the late cretaceous and active also during quaternary, may represent the seismogenic source. the deep geometric reconstruction of the fault shows that the hypocenter, at a depth of 25–30 km, roughly lies on the fault plane, thus determining the epicenter at about 15 km southwards of the surface fault trace; (iv) in the central apulian foreland, seismites in the late pleistocene deposits, and recent large boulder accumulations caused by tsunami(s), may be the result of near field seismic shocks and not only the far field effects of distant seismogenic structures. acknowledgment we are grateful to v. scisciani and to an anonymous reviewer, whose suggestions and comments helped us to improve the manuscript. we are grateful also to b. tomljenović, t. fluksi and a. martek for the editorial management of the manuscript. we thank p. dellino, who stimulated a proficuous discussion on the earthquake object of the present paper. “fondo per le attività base di ricerca – 2017”, granted to v. festa, financially supported the present research study. references amato, a., bianchi, i. & piana agostinetti, n. (2014): apulian crust: top to bottom.– j. geodyn., 82, 125–137. doi: 10.1016/j.jog.2014.09.007 argnani, a., frugoni, f., cosi, r., ligi, m. & favali, p. (2001): tectonics and seismicity of the apulian ridge south of the salento penisula (southern italy).– ann. geofis., 44/3, 527–540. bally, a.w., burbi, l., cooper, c. & gheraldoni, r. (1986): balanced sections and seismic reflection profiles across the central apennines.– mem. soc. geol. it., 35, 257–310. borgomano, j. (2000): the upper cretaceous carbonates of the gargano-murge region, southern italy: a model to platform-to-basin transition.– aapg bull., 84/10, 1561–1588. brandano, m., morsilli, m., vannucci, g., parente, m., bosellini, f. & mateu-vicens, g. (2010): rhodolith-rich lithofacies of the porto badisco calcarenites (upper chattian, salento, southern italy).– ital. j. geosci., 129/1, 119–131. doi: 10.3301/ijg.2009.10 butler, r.w.h. (2009): relationships between the apennine thrust belt, foredeep and foreland revealed by marine seismic data, offshore calabria.– ital. j. geosci., 128/2, 269–278. doi: 10.3301/ijg.2009.128.2.269 calais, e., camelbeeck, t., stein, s., liu, m. & craig, t.j. (2016): a new paradigm for large earthquakes in stable continental plate interiors.– geophys. res. lett., 43, 10,621–10,637. doi:10.1002/2016gl070815. castello, b., selvaggi, g., chiarabba, c. & amato, a. (2006): csi catalogo della sismicità italiana 1981–2002, versione 1.1.– ingv-cnt, roma. chiarabba, c., jovane, l. & di stefano, r. (2005): a new view of italian seismicity using 20 years of instrumental recordings.– tectonophysics, 395, 251–268. doi: 10.1016/j.tecto.2004.09.013 chilovi, c., de feyter, a.j. & pompucci, a. (2000): wrench zone reactivation in the adriatic block: the example of the mattinata fault system (se italy).– b. soc. geol. it., 119, 3–8. ciaranfi, n., pieri, p. & ricchetti, g. (1988): note alla carta geologica delle murge e del salento (puglia centromeridionale).– mem. soc. geol. it., 41, 449–460. de alteriis, g. (1995): different foreland basins in italy: examples from the central and southern adriatic sea.– tectonophysics, 252, 349–373. doi: 10.1016/00401951(95)00155-7 de’ dominicis, a. & mazzoldi, g. (1987): interpretazione geologico-strutturale del margine orientale della piattaforma apula.– mem. soc. geol. it., 38, 163–176. figure 5. block-diagram showing the deep geometric reconstruction of the faults detected in the study area (see fig. 4). the hypocenter of the march 23rd 2018 earthquake is approximately lying on the s-dipping fault plane, making plausible the association of this seismic event to the deepest segment of this fault. g eo lo gi a c ro at ic a geologia croatica 72/2144 del gaudio, v., festa, v., ripa, r.r., iurilli, v., pierri, p., calcagnile, g., moretti, m., pieri, p. & tropeano, m. (2001): evidence of apulian crustal structures related to low energy seismicity (murge – southern italy).– ann. geofis., 44(5/6), 1049–1066. del gaudio, v., pierri, p., calcagnile, g. & venisti, n. (2005): characteristics of the low energy seismicity of central apulia (southern italy) and hazard implications.– j. seismol., 9, 39–59. doi: 10.1007/s10950-005-1593-9 del gaudio, v., pierri, p., frepoli, a., calcagnile, g., venisti, n. & cimini, g.b. (2007): a critical revision of the seismicity of northern apulia (adriatic microplate – southern italy) and implications for the identification of seismogenic structures.– tectonophysics, 436, 9–35. doi: 10.1016/j.tecto.2007.02.013 de lorenzo, s., romeo, a., falco, l., michele, m. & tallarico, a. (2014): a first look at the gargano (southern italy) seismicity as seen by the local scale otrions seismic network.– ann. geophys. italy, 57/4, 1–14. doi: 10.4401/ ag-6594 di bucci, d., caputo, r., mastronuzzi, g., fracassi, u., selleri, g. & sansò, p. (2011): quantitative analysis of extensional joints in the southern adriatic foreland (italy), and the active tectonics of the apulia region.– j. geodyn., 51, 141–155. doi: 10.1016/j.jog.2010.01.012 di bucci, d., ravaglia, a., seno, s., toscani, g., fracassi, u. & valensise, g. (2006): seismotectonics of the southern apennines and adriatic foreland: insights on active regional e-w shear zones from analogue modeling.– tectonics, 25, tc4015. doi:10.1029/ 2005tc001898 diss working group (2018): database of individual seismogenic sources (diss), version 3.2.1: a compilation of potential sources for earthquakes larger than m 5.5 in italy and surrounding areas.– istituto nazionale di geofisica e vulcanologia. doi: 10.6092/ingv.it-diss3.2.1 doglioni, c., mongelli, f. & pieri, p. (1994): the puglia uplift (se italy): an anomaly in the foreland of the apenninic subduction due to buckling of a thick continental lithosphere.– tectonics, 13, 1039–1321. doi: 10.1029/94tc01501 emodnetnet (2017): european marine observation and data network, portal for bathymetry (last upgrade).– http://www.emodnet-bathymetry.eu fantoni, r. & franciosi, r. (2010): tectono-sedimentary setting of po plain and adriatic foreland.– rend. lincei-sci. fis., 21/1, 197–209. doi: 10.1007/s12210010-0102-4 festa, v. (2003): cretaceous structural features of the murge area (apulian foreland, southern italy).– eclogae geol. helv., 96, 11–22. doi: 10.5169/seals-169003 festa, v., langone, a., caggianelli, a. & rottura, a. (2010): dike magmatism in the sila grande (calabria, southern italy): evidence of pennsylvanian– early permian exhumation.– geosphere, 6/5, 549–566. doi: 10.1130/ges00578.1 festa, v., sabato, l. & tropeano, m. (2018): 1:5,000 geological map of the upper cretaceous intraplatform-basin succession in the “gravina di matera” canyon (apulia carbonate platform, basilicata, southern italy).– ital. j. geosci., 137/1, 3–15. doi: 10.3301/ijg.2017.12 finetti, i.r. & del ben, a. (2005): crustal tectono-stratigraphic setting of the adriatic sea from new crop seismic data.– in: finetti, i.r. (ed.): crop project: deep seismic exploration of the central mediterranean and italy. elsevier, amsterdam, 519–547. fracassi, u. & valensise, g. (2007): unveiling the sources of the catastrophic 1456 multiple earthquake: hints to an unexplored tectonic mechanism in southern italy.– b. seismol. soc. am., 97, 725–748. doi: 10.1785/0120050250 galli, p. (2000): new empirical relationships between magnitude and distance for liquefaction.– tectonophysics, 324, 169–187. doi: 10.1016/s0040-1951(00)00118-9 harding, t.p. (1985). seismic characteristics and identification of negative flower structures, positive flower structures, and positive structural inversion.– am. assoc. petr. geol. b., 69/4, 582–600. johnston, a.c. & kanter, l.r. (1990). earthquakes in stable continental crust.– scientific american, 262/3, 68–75. doi:10.1038/scientificamerican0390-68 kastelic, v., vannoli, p., burrato, p., fracassi, u., tiberti, m.m. & valensise, g. (2013): seismogenic sources in the adriatic domain.– mar. petrol. geol., 42, 191–213. doi: 10.1016/j.marpetgeo.2012.08.002 locati, m., camassi, r., rovida, a., ercolani, e., bernardini, f., castelli, v., caracciolo, c.h., tertulliani, a., rossi, a., azzaro, r., d’amico, s., conte, s. & rocchetti, e. (2016): dbmi15, the 2015 version of the italian macroseismic database.– istituto nazionale di geofisica e vulcanologia. doi: 10.6092/ingv.it‐dbmi15 mastrogiacomo, g., moretti, m., owen, g. & spalluto, l. (2012): tectonic triggering of slump sheets in the upper cretaceous carbonate succession of the porto selvaggio area (salento peninsula, southern italy): synsedimentary tectonics in the apulian carbonate platform.– sediment. geol., 269–270, 15–27. doi: 10.1016/j.sedgeo.2012.05.001 mastronuzzi, g. & sansò, p. (2004): large boulder accumulations by extreme waves along the adriatic coast of southern apulia (italy).– quatern int., 120, 173–184. doi: 10.1016/j.quaint.2004.01.016 merlini, s., cantarella, g. & doglioni, c. (2000): on the seismic profile crop m5 in the ionian sea.– b. soc. geol. it., 119, 227–236. morelli, d. (2002): evoluzione tettonico-stratigrafica del margine adriatico compreso tra il promontorio garganico e brindisi.– mem. soc. geol. it., 57, 343–353. moretti, m. (2000): soft-sediment deformation structures interpreted as seismites in middle-late pleistocene aeolian deposits.– sediment. geol., 135, 167–179. doi: 10.1016/s0037-0738(00)00070-1 moretti, m., alfaro, p. & owen, g. (2016): the environmental significance of soft-sediment deformation structures: key signatures for sedimentary and tectonic processes.– sediment. geol., 344, 1–4. doi: 10.1016/j.sedgeo.2016.10.002 moretti, m., pieri, p. & tropeano, m. (2002): late pleistocene soft-sediment deformation structures interpreted as seismites in paralic deposits in the city of bari (apulian foreland – southern italy).– geol. s. am. s., 359, 75–85. doi: 10.1130/0-8137-2359-0.75 moretti, m. & van loon (2014): restrictions to the application of ‘diagnostic’ criteria for recognizing ancient seismites.– journal of palaeogeography, 3, 162–173. doi: 10.3724/sp.j.1261.2014.00050 morsilli, m., hairabian, a., borgomano, j., nardon, s., adams, e. & gartner, g.b. (2017): the apulia carbonate platform-gargano promontory, italy (upper jurassic-eocene).– am. assoc. petr. geol. b., 101/4, 523–531. doi: 10.1306/011817dig17031 nicolai, c. & gambini, r. (2007): structural architecture of the adria platform-and-basin system.– b. soc. geol. it., special issue, 7, 21–37. papadopoulos, g.a. & lefkopoulos, g. (1993): magnitude-distance relations for liquefaction in soil from earthquakes.– b. seismol. soc. am., 83/3, 925–938. patacca, e. & scandone, p. (2004): the 1627 gargano earthquake (southern italy): identification and characterization of the causative fault.– j. seismol., 8, 259–273. doi: 10.1023/b:jose.0000021393.77543.1e pieri, p., festa, v., moretti, m. & tropeano, m. (1997): quaternary tectonic activity of the murge area (apulian foreland – southern italy).– ann. geofis., 40/5, 1395–1404. pierri, p., de lorenzo, s. & calcagnile, g. (2013): analysis of the low-energy seismic activity in the southern apulia (italy).– ojer, 2, 91–105. doi: 10.4236/ojer.2013.24010 puglia.con (2015): conoscenza condivisa per il governo del territorio (last upgrade).– http://www.sit.puglia.it ricchetti, g., ciaranfi, n., luperto sinni, e., mongelli, f. & pieri, p. (1988): geodinamica ed evoluzione sedimentaria e tettonica dell’avampaese apulo.– mem. soc. geol. it., 41, 57‒82. rovida, a., locati, m., camassi, r., lolli, b. & gasperini, p. (2016): cpti15, the 2015 version of the parametric catalogue of italian earthquakes.– istituto nazionale di geofisica e vulcanologia. doi: 10.6092/ingv.it‐cpti15 sarma, d.o. (2009): geostatistics with applications in earth sciences, 2nd ed.– springer netherlands – capital publishing company, new delhi, india, 206 p. isbn: 978-1-4020-9379-1 scisciani, v. & calamita, f. (2009): active intraplate deformation within adria: examples from the adriatic region.– tectonophysics, 476, 57–72. doi: 10.1016/j. tecto.2008.10.030 spalluto, l., pieri, p. & ricchetti, g. (2005): le facies carbonatiche di piattaforma interna del promontorio del gargano: implicazioni paleoambientali e correlazioni con la coeva successione delle murge.– b. soc. geol. it., 124, 675–690. stock, c. & smith, e.g.c. (2000): evidence for different scaling of earthquake source parameters for large earthquakes depending on faulting mechanism.– geophys. j. int., 143, 157–162. doi: 10.1046/j.1365-246x.2000.00225.x tondi, e., piccardi, l., cacon, s., kontny, b. & cello, g. (2005): structural and time constraints for dextral shear along the seismogenic mattinata fault (gargano, southern italy).– j. geodyn., 40, 134–152. doi: 10.1016/j.jog.2005.07.003 tropeano, m., pieri, p., moretti, m., festa, v., calcagnile, g., del gaudio, v. & pierri, p. (1997): quaternary tectonics and seismotectonic features of the murge area (apulian foreland, se italy).– il quaternario, 10/2, 543–548. tropeano, m. & sabato, l. (2000): response of plio-pleistocene mixed bioclastic-lithoclastic temperate-water carbonate systems to forced regressions: the calcarenite di gravina formation, puglia, se italy.– in: hunt, d. & gawthorpe, r.l. (eds.): sedimentary responses to forced regressions. geol. soc. spec. publ., 172, 217–243. doi: 10.1144/gsl.sp.2000.172.01.11 tropeano, m., spalluto, l., moretti, m., pieri, p. & sabato, l. (2004): depositi carbonatici infrapleistocenici di tipo foramol in sistemi di scarpata (salento – italia meridionale).– il quaternario, 17/2, 537–546. videpi (2015): progetto videpi, visibilità dei dati afferenti all’attività di esplorazione petrolifera in italia (last upgrade).– http://unmig.sviluppoeconomico.gov.it/videpi/ wang, j.h. & ou, s.s. (1998): on scaling of earthquake faults.– b. seismol. soc. am., 88, 758–766. wells, d.l. & coppersmith, k.j. (1994): new empirical relationships among magnitude, rupture length, rupture width, rupture area and surface displacement.– b. seismol. soc. am., 84, 974–1002. zappaterra, e. (1994): source-rock distribution model of the periadriatic region.– am. assoc. petr. geol. b., 78, 333–354. 2018 | 71/3 | 135 – 146 | 9 figs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the konkian is the middle miocene stage of the eastern paratethys that corresponds to the nn6-nn7 nannoplankton zone (nevesskaya et al., 2005), to the serravallian of the global time scale and to the upper badenian (kosovian) of the central paratethys (hilgen et al., 2012). the karaganian/konkian boundary is dated at 13.4 ma, and the konkian/sarmatian boundary is dated at 12.65 ma (palcu et al., 2017). the konkian (upper badenian) time is characterized by a marine transgression which reactivated connections between the central and eastern paratethys. the preceding karaganian time was characterized by euryhaline conditions which correspond to the badenian salinity crisis in the middle badenian of central paratethys (e.g. muratov & nevesskaya, eds., 1986; peryt, 2006). after the konkian (up per badenian), the sarmatian basin was characterized by palaeoenvironmen tal changes and the appearance of an endemic fauna in the eastern and central paratethys. (e.g. muratov & nevesska ya, eds., 1986; nevesskaya et al., 2005; hilgen et al., 2012). the aim of this study is to understand how the foraminiferal assemblages developed and to show the differences between the shallow-water and deeper water basins in the konkian. the results are discussed in the context of temporal and spatial changes of foraminiferal species diversity and presented together with the analysis of molluscs as an additional group in the various konkian facies of the southern ukraine. 2. the konkian regional stage of the eastern paratethys 2.1. peculiarities of the konkian stratigraphy of the eastern paratethys the first stratigraphic studies of the neogene of the eastern paratethys were based on identification of mollusc assemblages. if biostratigraphy of the konkian (middle miocene of the eastern paratethys) deposits of southern ukraine based on foraminifera yuliia vernyhorova national academy of sciences of ukraine, institute of geological sciences, department of stratigraphy and palaeontology of the cenozoic deposits, o. honchar str., 55 b, kyiv, 01601 ukraine; (july.vern@gmail.com) doi: 10.4154/gc.2018.18 abstract the konkian (middle miocene) foraminiferal assemblages and molluscs from five wells situated in southern ukraine were studied in order to correlate the palaeoecology and biostratigraphy of the coeval palaeobasins with different environmental conditions. the article contains comprehensive analysis of controversial issues of the konkian stratigraphy of the eastern paratethys and additional keys for determination of konkian development phases by foraminifera and molluscs. five stenohaline normal-marine, two euryhaline and one mixed foraminiferal assemblage were identified in different levels in the investigated wells with the analysis of their accordance to different molluscs assemblages. the study defines an isochronous foraminiferal assemblage for some wells, suggests a palaeoecological and stratigraphic reconstuction of the middle miocene sediments in the eastern black sea region and recognizes two models of development of the konkian foraminiferal assemblages. these models show the differences between environmental conditions in the shallow-water basin of the eastern black sea region and deeper water basin of the kerch peninsula at that time. while the eastern black sea region was influenced by frequent and abrupt changes in environmental conditions during almost all konkian time, a relatively deeper basin of the kerch peninsula had a successive phase. the late konkian time created similar depositional conditions for both basins. certain species of mollusсs were traced in sections, then these deposits were defined as the same age and such mollusc associations were identified as “beds with molluscs” (e.g. andrusov, 1917; arkhanguelsky, 1930). several “beds with molluscs” were determined in the konkian deposits: beds with ve­ nus konkensis in the northern black sea region of the southern ukraine (sokolow, 1899), were named later as the veselyanka beds by merklin (1953); the pholadidae beds on the kerch peninsula of the southern ukraine (andrusov, 1917); the kartvel beds in georgia (davitashvily, 1930); the sartagan beds in transcaspian (zhizhchenko, 1937a, b). the kartvel beds are characterized (fig. 1) by pholadidae (barnea pseu­ doustjurtensis bogatchev, b. ustjurtensis (eichwald), b. kubanica (zhizhchenko) b. scrinia (bogatschev) etc.); the sartagan beds are defined as deposits with a rich marine stenohaline konkian mollusc fauna; the veselyanka beds are defined as deposits with euryhaline konkian molluscs (merklin, 1953; vereshagin & mironova, 1982; muratov & nevesskaya, eds., 1986). later, such beds with molluscs were found in the konkian of other areas of the eastern paratethys (e.g. varentsov, 1950; merklin, 1953; muratov & nevesskaya, eds., 1986). shallow-water konkian deposits often comprise beds with ervilia trigonula sokolov or beds with e. trigonula and barnea pseudoustjurtensis, b. kubanica in the southern ukraine (molyavko, 1960; barg, 1969). therefore, they were called the “ervilia-pholadidae beds” and were also considered as kartvel beds (barg, 1969). the age of the kartvel beds has been under discussion. these beds were defined as belonging to both the karaganian and the konkian regiostages based on the mollusc species composition (pholadidae) (zhizhchenko, 1937a, 1937b; buriak, 1965). they were also considered as the final stage of the karaganian (sudo, 1961; nevesskaya et al., 2005) or were article history: manuscript received january 30, 2018 revised manuscript accepted september 18, 2018 available online october 24, 2018 keywords: foraminifera, mollusca, biostratigraphy, palaeocology, konkian, upper badenian, eastern paratethys, southern ukraine g eo lo gi a c ro at ic a geologia croatica 71/3136 determined as the individual kartvelian regiostage (zhgenti, 1976; ilyina, 2000; zhgenti & maissuradze, 2016). the presence of typical konkian species of foraminifera (varidentella reussi sartaganica krasheninnikov, nodo­ baculariella konkensis bogdanowicz, nonion tauricus krasheninnikov, reussella spinulosa (reuss), cassi­ dulina bulbiformis krasheninnikov, discorbis kartvelicus krasheninnikov, d. supinus krasheninnikov etc.) and ostracods (leptocythere distenta schneider, loxoconcha spongiosa ljuljev, trachyleberis lascarevi schneider etc.) in the kartvel beds is a sufficient basis to determine them as the konkian regiostage (fig. 1) (krasheninnikov, 1959; barg & ivanova, 2000; krasheninnikov et al., 2003; barg & stepaniak, 2003; bondar, 2004; prisyazhnyuk et al., 2007; golovina et al., 2009; vernigorova, 2009; ivanova, 2012; vernyhorova, 2014, 2015a, b, 2016). the konkian age of the sartagan beds, was confirmed not only on the basis of molluscs but also by normal-marine assemblages of konkian foraminifera (fig. 1) such as quinqueloculina minakovae ukrainica didkowski, varidentella reussi sartaga nica, nodobaculariella konkensis, n. didkowskii bogdanowicz, articulina vermicularis bogdanowicz, melonis soldanii (orbigny), borelis melo (fichtel & moll), cassidulina bulbiformis, discorbis kartvelicus, d. supinus, reussella spinu­ losa, etc. (krasheninnikov, 1959; didkovskiy, 1959; djanelidze, 1970) and the konkian ostracods such as trachyl­ eberis semiornara ljuljev, t. golubjatnikovi schneider, t. lascarevi, leptocythere distenta, loxoconcha spongiosa, aglaio­ cypris konkensis schneider, aurila similis (reuss) etc. (barg & stepaniak, 2003; bondar, 2004; prisyazhnyuk et al., 2007). the konkian age of the veselyanka beds, except for molluscs, is also confirmed by euryhaline assemblages of konkian foraminifera (fig. 1) such as nonion tauricus krasheninnikov, elphidium farsiensis krasheninnikov, e. horri­ dum bogdanowicz, etc. (krasheninnikov, 1959; didkovskiy, 1959; djanelidze, 1970) and the konkian ostracods (barg & stepaniak, 2003; bondar, 2004; prisyazhnyuk et al., 2007). according to the recent research on the konkian/sarmatian boundary in georgia, the sarmatian age was suggested for the veselianka beds. this conclusion was drawn from a comparison of foraminiferal assemblages from the veselianka beds with those from the sartagan beds and the lower sarmatian deposits (koiava et al., 2016). however, these foraminiferal data were not consistent with other palaeontological data (e.g. molluscs, ostracods) from the konkian deposits which suggested a konkian age for the veselianka beds (e.g. merklin, 1953; muratov & nevesskaya, eds., 1986). the konkian regiostage was subdivided into three substages: kartvel beds, sartagan beds and veselyanka beds by merklin (1953). however, there are researchers who do not support merklin’s point of view since the konkian sections in different areas of the eastern paratethys have different and irregular deposit patterns with various “beds with molluscs” (varentsov, 1950; buleishvili, 1960; nosovskiy, 1960; chikovani, 1964; barg, 1969; 2008; prisyazhnyuk et al., 2007; vernigorova, 2008, 2009, 2012). also, some sections may have several levels with the same type of fossiliferous beds, while in others some horizons of such beds are missing (review presented in vernigorova, 2009). in addition, the konkian deposits in southern ukraine comprise molluscs or foraminiferal assemblages with both normal-marine and euryhaline species (didkovskiy, 1959; molyavko, 1960; barg, 1969; vernigorova, 2012). as a result, researchers have two different opinions on the konkian stratigraphy (fig. 2). the first group considers that the kartvel beds, the sartagan beds and the veselyanka beds represent development phases in the konkian basin (merklin, 1953; barg, 1993; barg & stepaniak, 2003; ivanova, 2012; starin, 2012; koiava et al., 2016). they are therefore used in regional stratigraphy as the konkian substages. the second group thinks that these beds can be associated with different environmental conditions which could appear at different times during the konkian. so they are used as additional biostratigraphic subdivisions such as “beds with fauna” (according to zhamoida, ed., 1977; teslenko, ed., 1997; gozhyk, ed., 2012) in the local stratigraphy for the correlation of sections and palaeoenvironmental reconstructions of separate areas (varentsov, 1950; buleishvili, 1960; chikovani, 1964; buriak, 1965; prisyazhnyuk et al., 2007; vernyhorova, 2014, 2015a, b, 2016). thus, today the terms the kartvel beds, the sartagan beds and the veselyanka beds are not clearly defined, as they can refer to stratigraphic horizons or palaeoecological conditions. so, there are problems in the case of their use for the correlation when it is necessary to compare deposits with the same names but they can have different semantic meanings. therefore, it is possible to agree with the proposal of ilyina (2000) not to divide the konkian stage into several substages and not to call these units by their own names such as the kartvel beds, the sartagan beds and the veselyanka beds. however in the case when a researcher decides to divide the konkian into substages it is proposed to use the terms: lower, middle and upper konkian substages. if a rebarnea pseudoustjurtensis, b. ustjurtensis, b. kubanica, ervilia trigonula konkian characteristic species; but there aren't specific and characteristic species for identification just these beds. there are several assemblages with different paleoecological characteristics konkian characteristic species; predominance of stenohaline species of genera: lagena, nodobaculariella, spirolina, globulina, virgulina, reussella, pyrgo, etc. konkian characteristic species; predominance of stenohaline species of genera: chama, chlamys, anadara, turreitella, spiratella etc. konkian characteristic species; predominance of euryhaline species of genera: elphidium, nonion, ammonia. presence of a small number of normal-marine species of genera: bulimina, cassidulina, quinqueloculina etc. is possible konkian characteristic species; predominance of euryhaline species of genera: parvivenus, alvenius, parvicardium, sandbergeria etc. veselyanka bedskartvel beds mollusca foraminifera sartagan beds figure 1. typical species of molluscs and foraminifera from the konkian of the eastern parethetys (according to zhizhchenko, 1937a, b; merklin, 1953; krash­ eninnikov, 1959; barg, 1969; ivanova, 2012, etc.). g eologia c roatica vernyhorova yuliia: biostratigraphy of the konkian (middle miocene of the eastern paratethys) deposits of southern ukraine based on foraminifera 137 searcher still decides to use individual names for these substages then it is proposed not to call them as beds, but rather the kartvelian substage, the sartaganian substage and the veselyankian substage (e.g. maissuradze et al., 2014; palcu et al., 2017). in addition, since the initial criteria for recognition of the konkian substages were not universal, it is necessary to clarify the definitions for each of these substages by adding criteria to aid more accurate recognition of them in sections. at the same time, it is necessary to take into account the fact that the different facies of the konkian deposits in the eastern paratethys generally contain stable species assemblages of fauna with certain palaeoecological characteristics that are separate biostratigraphic subdivisions “beds with the fauna” (according to zhamoida, ed., 1977; teslenko, ed., 1997; gozhyk, ed., 2012). in this case, it has been proposed to not call these subdivisions names such as the kartvel beds, the sartagan beds, the veselianka beds, but to name them after the characteristic fossils (e.g. limestones with ervilia trigonula, barnea pseudoustjurtensis) (vernyhorova, 2014, 2015a,b, 2016). 2.2. criteria for determination of the initial (early) and final (late) development stages of the konkian basin by molluscs and foraminifera since the different beds with fauna may occur at different stratigraphic levels of the konkian of the eastern paratethys they are not unique for particular development phases of the konkian basin. therefore, additional criteria for determination of the development stages of the konkian basin are needed. experience in the study of foraminifera and molluscs in the konkian deposits from different areas of the southern ukraine, the ciscaucasus and the mangyshlak peninsula (vernigorova et al., 2006, 2009; vernigorova, 2008, 2009, 2012; golovina et al., 2009; bratishko et al., 2015) allows the definition of additional criteria for determination of the initial (early) and final (late) development stages of the konkian basin (vernyhorova, 2015a; popov et al., 2016). an initial stage of the konkian basin development may be recognized by a specific foraminiferal assemblage with a predominance of the genera cassidulina and discorbis (cassidulina bulbiformis, c. bogdanowiczi konenkova, discorbis kartve­ licus etc.) (fig. 3). this regular trend can be observed in some relatively deep konkian deposits (clays and marls) of the eastern part of the crimean peninsula, the kerch peninsula and the ciscaucasus (krasheninnikov, 1959; bogdanowicz, 1965; vernyhorova, 2015a; popov et al., 2016; palcu et al., 2017). this stage is clearly visible only in the most complete konkian sections. otherwise the stage is difficult to identify, because similar foraminiferal assemblages are present in different konkian stratigraphic horizons, especially in the shallow-water deposits (vernyhorova 2014, 2015a, b, 2016). criteria for determining of the initial (early) development phase of the konkian by molluscs are also not yet clearly defined. the early konkian may contain beds with ervilia and pholadidae. however, as has been indicated above, they are also present in other stratigraphic horizons. the final development phase of the konkian basin can be defined more precisely. these sediments comprise not only euryhaline species of molluscs and foraminifera which are typical for the konkian basin but also a small amount of early sarmatian species (e.g. molluscs – obsoletiforma lithopodolica ruthenica (hilber), ervilia dissita dissita (eichwald) small-sized tests; foraminifera – elphidium horridum, porosononion mart­ konkian veselyankian (veselyanka beds) sartaganian (sartagan beds) kartvelian (kartvel beds) beds with lutetia (spaniodontella) gentilis – research interval ? karaganian sarmatian sarmatian deposits sarmatian depositssarmatian se rra va llia n ba de ni an sy st em n e o g e n e m i o c e n e m i d d l e se rie s su bse rie s st ag e nothern black sea region crimea peninsula kerch peninsula eastern paratethys regional stage central paratethys stage veselyanka beds representations about the stratigraphic value of “beds with fauna”gts, 2004 "beds with molluscs" are reflection regional substages of the konkian "beds with molluscs" are biostratigraphic units that are traced on different levels in coeval facies sartagan beds west centre east kartvel beds veselyanka beds veselyanka beds sartagan beds kartvel beds kartvel beds beds with lutetia (spaniodontella) gentilis nothern black sea region crimea peninsula kerch peninsula "beds with molluscs" are not recognized in sections figure 2. the different understanding of stratigraphic value of the kartvel beds, sartagan beds and veselyanka beds in the southern ukraine deposits in strati­ graphic schemes of the konkian of the eastern paratethys. ? predominance of konkian euryhaline species and presence of a small number of the early sarmatian species (e.g. e. dissita dissita, obsoletiforma lithopodolica ruthenica; their shells have small sizes) a variety of molluscs and foraminiferal konkian assemblages that have different paleoecological characteristics. it is depend on environmental conditions in different areas of the konkian basin especially in shallow-water deposits. predominance of konkian euryhaline species and presence of a small number of the early sarmatian species (e.g. e. horridum, porosononion martkobi, nonion bogdanowichi ) konkian characteristic species; reduced species composition of assemblages; normal-marine species; predominance of the genera cassidulina and discorbis (e.g. c. bulbiformis, c. bogdanowiczi, d. kartvelicus) molluscsphase of development late middle early ko nk ia n r eg io st ag e foraminifera figure 3. characteristics of the konkian development phases based on foraminifera and molluscs (vernyhorova, 2015a). g eo lo gi a c ro at ic a geologia croatica 71/3138 kobi (bogdanowicz), nonion bogdanowiczi voloshinova). this regular trend can be observed in the konkian sediments of the northern black sea region (including the konkian stratotype), on the kerch peninsula, the ciscaucasus and the mangyshlak peninsula (sokolow, 1899; liverovskaya, 1935; 1960; bogdanowicz, 1965; vernigorova et al., 2009; vernyhorova, 2014; bratishko et al., 2015; palcu et al., 2017). 3. the konkian lithofacies of the southern ukraine the konkian deposits of different lithofacies features are widespread in the southern ukraine (figs. 4, 5). shallow-water deposits (3-25 m thick) have accumulated in the northern black sea region and in most parts of the crimean peninsula (e.g. molyavko, 1960; barg & stepaniak, 2003). different types of limestones (hladkivka formation, tarkhankut formation, mekenziev strata) prevail in the western part of the northern black sea region and in the western and southern parts of the crimean peninsula; sands and sandstones (novokakhovka formation) are more abundant in the south-east of the northern black sea region and in the northern and central parts of the crimean peninsula; laminated green-grey clays with varying sandy admixtures (tymoshivka formation) occur in the north-eastern part of the northern black sea region (vernyhorova, 2015b, 2016). the konkian deposits in these areas have sedimentation hiatuses and these strata are not stratigraphically complete (molyavko, 1960; didkovskiy & kulichenko, 1975, vernyhorova, 2015b, 2016). more deep-water deposits (36-155 m thickness) are monotonous dark gray clays, partially laminated with rare sandy admixtures that have accumulated in the kerch peninsula and in the south-eastern parts of the crimean peninsula. they differ from other konkian deposits of the southern ukraine by their lithological peculiarities and occurrence of more deep-water species of fauna (e.g. andrusov, 1917; osipov, 1927; arhanguelsky, 1930; arkhanguelsky, ed., 1940; molyavko, 1960; barg & stepaniak, 2003; vernyhorova, 2014). these konkian deposits represent a complete stratigraphic sequence and all of them are combined in the petrovske formation (vernigorova et al., 2012; vernyhorova, 2014). 4. materials and methods the konkian deposits were studied in five wells from several regions of the southern ukraine (figs. 4, 6). there are four wells from the eastern black sea region (upper part of the tymoshivka formation): well 8z (altitude – 69.5 m; thickness of the konkian deposits – 4.2 m; 26 samples selected); well 9 (altitude – 69.7 m; thickness of the konkian deposits – 1.7 m; 24 samples selected); well 6 (altitude – 30.5 m; thickness of the konkian deposits – 5.0 m; 33 samples selected); well 8m (altitude – 86,0 m; thickness of the konkian deposits – 10.0 m; 47 samples selected) and one well from the kerch peninsula (petrovske formation): well 20 (altitude – 17.0 m; thickness of the konkian deposits – 51.0 m; 82 samples selected). the stratigraphic sequence of these deposits was determined on the basis of foraminiferal and mollusc assemblages. mollusc data from well 8z were defined also by prisyazhnyuk et al., 2007 and were used in this research. during analysis, data on the konkian foraminiferal and molluscs assemblages and lithological features of the konkian deposits from other areas of the southern ukraine from published literature (e.g. didkovskiy, 1959; molyavko, 1960; barg, 1993; barg & ivanova, 2000) and industrial-geological reports (1947–2015) were also utilised. the selection and determination of all species of foraminifera was made from 300 g of sediment sample that was previously washed through a 76 μm sieve (e.g. vernigorova et al., 2006; vernigorova, 2008). descriptions and images of foraminitokmachka m ol oc hn a vovcha sam ar a d ni pr o inhul et s v ys un saksah an in hu l pivdennyi buh kropyvnytskyi kamianske pavlohrad kryvyi rih marhanetsnikopol melitopol berdiansk dzhankoi kerch feodosiia yalta sevastopol yevpatoriia dnipro zaporizhzhia kherson simferopol mykolaiv ii ii i i v v iii iii iv ivmekenziev strata hladkivka formation tymoshivka formation vi petrovske formationnovokakhovka formation tarkhankut formation vi ukraine – crimean peninsula – northern black sea region – kerch peninsula location of the study area 8z 9 6 8m 20 8z; 9; 6; 8m; 20 – investigated wells fig. 4 vernyhorova figure 4. location map of the studied wells in different facies of the eastern black sea region and the kerch peninsula. g eologia c roatica vernyhorova yuliia: biostratigraphy of the konkian (middle miocene of the eastern paratethys) deposits of southern ukraine based on foraminifera 139 fera from the neogene deposits of the eastern paratethys were used for their species determination (krasheninnikov, 1959; bogdanowicz, 1952; djanelidze, 1970; bugrova et al., 2005). molluscs were extracted first, both from the vicinity of the wells and then during sample processing in the laboratory. traditional conchological methods were used to identify molluscs (ilyina, 1993; nevesskaya et al., 1993). the number of tests of each foraminifera species was counted in each sample for each well. species were considered dominant when their percentage of tests was more than the percentage of tests of other species. the foraminiferal assemblages were compared based on the similarity of foraminifera species composition and the presence of the same dominant species. a definition of normal–marine, euryhaline, and mixed foraminiferal assemblages became possible after assessment of the palaeoecological characteristics of the foraminifera species composition of each assemblage. comprehensive analysis of the data obtained from the konkian stratigraphy of the southern ukraine is represented here. descriptions and graphic presentation of qualitative and quantitative analyses of foraminiferal assemblages in the konkian deposits from each of these wells is described in detail in: vernigorova, 2008, 2009, 2012; vernigorova et al., 2009. palaeoecological characteristics of foraminifera and molluscs (their classification as stenohaline, normal-marine and euryhaline species) is based on data from: arkhanguelsky, ed., 1940; merklin, 1953; didkovskiy & kulichenko, eds., 1975; muratov & nevesskaya, eds., 1986; didkovskiy, 1959; krasheninnikov, 1959; bogdanowicz, 1965; djanelidze, 1970; ilyina, 2000; maissuradze et al., 2014; zhgenti & maissuradze, 2016, etc. analysis of changes of foraminifera and molluscs species composition gave possibility to understand the peculiarities of the development of different regions of southern ukraine in konkian time. palaeoecological and stratigraphic reconstruction of the middle miocene deposits of the eastern black sea region was created using palaeoecological, bioand lithostratigraphic data that were obtained both from published literature and the author’s research (e.g. arkhanguelsky, ed., 1940; didkovskiy, 1959; molyavko, 1960; barg, 1969, 2008; prisyazhnyuk et al., 2007; vernigorova, 2008, 2009, 2012; vernigorova et al., 2009; vernyhorova, 2014, 2015b, 2016). 5. results and discussion 5.1. peculiarities of foraminifera and molluscs assemblages in the konkian deposits of the studied area five stenohaline normal-marine (nm1-nm5), two euryhaline (eh1, eh2) and one mixed (mx) foraminiferal assemblages were identified within the cores of the investigated wells at different levels (figs. 7, 8). they are characterized by the predominance of either normal-marine or euryhaline foraminiferal taxa (e.g. krasheninnikov, 1959; bogdanowicz, 1965; djanelidze, 1970; krasheninnikov et al., 2003) or an equal number of marine and euryhaline foraminiferal taxa (didkovskiy, 1959; vernigorova, 2012) accordingly. assemblage nm1 is characterized by dominant species: quinqueloculina minakovae ukrainica, q. pseudoangustissima krasheninnikov, q. ex gr. consobrina orbigny, variden­ tella reussi sartaganica, triloculina inflata orbigny, t. ebersini didkovskiy, globulina gibba orbigny and subdominant species: triloculina inornata orbigny, spiroloculina konkensis bogdanowicz, sigmoilina sp., florilus boueanus orbigny, nonion sp.1, elphidium joukovi serova, ammonia ex gr. bec­ carii (linné). it was determined in three wells in the eastern part figure 5. stratigraphic scheme of the konkian deposits of the southern ukraine (according to vernyhorova, 2014, 2015a, b, 2016). g eo lo gi a c ro at ic a geologia croatica 71/3140 -5 0,0 +5 -70 -65 -60 -55 -50 -45 -40 -35 -30 -25 -20 -15 -15 well 8z well 9 well 6 well 8m well 20 ab so lu te el ev at io n43,0 km west east 17,0 km west east 40,9 km north south 182 km north south 84,3 88,5 n1mc 82,2 84,0 n1chk 90,0 100,0 n1s2 85,0 90,0 16,2 67,2 n1s1 n1s1 n1s1 n1s1 n1krg tokmachka marhanets melitopol berdiansk dzhankoi kerch feodosiia zaporizhzhia 8z 9 6 8m 20 * – 8z; 9; 6; 8m; 20 – investigated wells * * * * * v vi iii i ii ii i v iii mekenziev strata tymoshivka formation vi petrovske formation the legend of wells see on fig. 8novokakhovka formation tarkhankut formation figure 6. location of the wells and schematic section of the konkian deposits from wells 8z, 9, 8m, and 20. g eologia c roatica vernyhorova yuliia: biostratigraphy of the konkian (middle miocene of the eastern paratethys) deposits of southern ukraine based on foraminifera 141 of the northen black sea region (figs. 6, 8). the well 8z (88.387.8 m) is characterized by the interbedding of light yellow-grey and green-grey loose or dense argillaceous limestones. well 9 (83.0-82.65 m) is characterized by light-gray with a greenish tinge, dense, laminated, carbonate clays with sandy grains on bedding planes. well 6 (87.15-87.0 m) is characterized by black with a greenish tinge argillite clays. different molluscs were found together with this foraminiferal assemblage (figs. 7, 8). namely, rare shells of mytilaster volhynicus (eichwald), ervilia pusilla tri­ gonula sokolov, gibbula aff. bajarunasi (kolesnikov), nassarius aff. karaganicus (zhizhchenko) were observed in well 8z; similar molluscs species composition and also many shells of ervilia pusilla trigonula were found in well 9; nassarius aff. karaganicus, ervilia pusilla trigonula and rare hydrobia sp., alvenius nitidus (reuss) were found in well 6. these are normal-marine mollusc assemblages (fig. 7) or sartagan beds (in the sense of merklin, 1953; muratov & nevesskaya, eds., 1986). also the numerous shells of ostracods, remnants of bryozoans and echinoid radiole were found together with this foraminiferal assemblage (figs. 7, 8). assemblage nm2 is characterized by a small number of specimens of: quinqueloculina gracilis karrer, q. aff. guri­ fo ra m in ife ra l a ss em bl ag es w el ls (in te rv al , m ) beds with predominance of normal-marine species beds with predominance of euryhaline species assemblage nm1 assemblage nm2 assemblage nm3 assemblage nm4 assemblage nm5 mixed assemblage mx assemblage eh1 assemblage eh2 dominant species: r. spinulosa, s. austriaca, s. aff. bidentata, d. cf. haueri, b. melo subdominant species: v. reussi sartaganica, nonionella ventragranossa, n. tauricus, el. antonina, elphidium sp. normal-marine: well 6 anadara turonica, v. (polititapes) vitaliana, p. praeplicata, e. pusilla trigonula, obsoletiforma lithopodolica ruthenica, retusa sp., n.millepunctata in upper parts of some konkian sections the same species compositions as eh1 assemblage and also admixture of shells of the early sarmatian species: e. reginum, e. horridum, q. consobrina sarmatica, articulina sp., entosolenia sp. euryhaline: well 8z rare shells of hydrobia sp., e. pusilla trigonula, alvenius nitidus and some terrestrial species shells detritus and rare small shells of cardium sp. well 20: 18,1-16,2 m different quantitaties of shells throughout the section: q. gracilis, q. guriana, b. floridana, b. dilatata, n. elongata, u. gracilissima, fursenkoina schreibersiana, g. aff. austriaca, d. kartvelicus, cassidulina sp. rare shells throughout the section well 20: 45,7-18,1 m s. konkensis, alvenius nitidus, mactra sp., and shells detritus beds with pholadidae well 20: 54,7-45,7 m many shells of barnea pseudoustjurtensis and shells detritus dominant species: p. subgranosus, el. macellum, a.ex gr. beccarii subdominant species: fl. boueanus, q. aff. guriana, v.reussi sartaganica, discorbis sp., n. tauricus, el.joukovi euryhaline: well 6: 88,5-87,5 m 87,35-87,3 m; 8m: 96,2-93,8 m 93,0-91,6 m 91,1-90,0 m a. nitidus, e. pusilla, venus sp. beds with pholadidae well 8m: 100,0-97,8 m 96,4-96,2 m beds with ervilia well 9: 84,0-83,93 m; well 6: 86,6-85,8 m many shells of e. pusilla trigonula equal quantities of shells: large shells of euryhaline species: porosononion subgranosus, e. aculeatum, a. ex gr. beccarii and small shells of stenohaline species: b. dilatata, n. elongata, u. gracilissima, fursenkoina schreibersiana, g. aff. austriaca, r. spinulosa, discorbis sp.1, cassidulina sp. euryhaline and spirialis: well 8m: 96,7; 93,5 m alvenius nitidus, e. pusilla trigonula, cardium sp., venus sp. and plus spiratella sp. shells detritus well 9: 83,7-83,5 m 83,3-85,8 m well 6: 88,0-87,5 m 87,0-86,6 m beds with pholadidae well 9: 83,50-83,32 m many shells of barnea pseudoustjurtensis and shell detritus small sizes, poor preservation, small number of shells: q. gracilis, q. minakovae ukrainica, q. ex gr. consobrina, q. aff. guriana, q. angustissima, v. reussi sartaganica, t. inflata, g.gibba, d. supinus, d. squamulus, spirolina sp., f. boueanus, nonion sp., a. ex gr. beccarii beds with pholadidae: well 8 many shells of barnea pseudoustjurtensis single shells of e. pusilla trigonula, hydrobia sp. equal quantities of shells: h. aff. podolica, hauerina sp. 1, hauerina sp. 2, discorbis sp. 1, discorbis? sp. 2 beds with ervilia and pholadidae: well 8z many shells of e. pusilla trigonula, barnea pseudoustjurtensis, hydrobia sp. and shells detritus dominant species: q. minakovae ukrainica, q. pseudoangustissima, q. ex gr. consobrina, v. reussi sartaganica, triloculina inflata, t. ebersini, globulina gibba subdominant species: t. inornata, s. konkensis, sigmoilina sp., f. boueanus, nonion sp.1, e. joukovi, a. ex gr. beccarii normal-marine: well 8z rare shells of m. volhynicus, e. pusilla trigonula, g. aff. bajarunasi, n.aff. karaganicus; bryozoans, echinoid radiole well 9 similar on well 8z but has also many shells of ervilia pusilla trigonula; bryozoans, echinoid radiole well 6 n. aff. karaganicus e.pusilla trigonula, rare:hydrobia sp., al.nitidus, bryozoans, echinoid radiole 8z (88,5-87,8m); 9 (83,0-82,65 m); 6 (87,15-87,0 m) 8z (87,8-87,0 m) 8z (86,9-86,3 m) 6 (87,3-87,2 m 85,8-85,0 m) 20 (67,2-18,1 m) kerch peninsula eastern part of the nothern black sea regioneastern part of the nothern black sea region kerch peninsula 9 (83,7-83,0 m); 6 (87,0-86,6 m); 8m (96,75-96,7 m 93,5-93,45 m) 9 (84,0-83,7m); 6 (88,5-87,5 m 87,35-87,3 m 86,6-85,8 m); 8m (100,0-96,5 m) 8z (86,3-84,3 m); 20 (18,1-16,2 m) m ol lu sc s as se m bl ag es figure 7. general characteristics of foraminiferal and mollusc assemblages in the studied wells (for detailed analyses of these assemblages in the konkian depo­ sits of each of these wells see also: prisyazhnyuk et al., 2007; vernigorova, 2008, 2009, 2012; vernigorova et al., 2009). g eo lo gi a c ro at ic a geologia croatica 71/3142 nm1 eh1 nm nm eh 16,2 18,0 20,0 22,0 24,0 26,0 28,0 30,0 32,0 34,0 36,0 38,0 40,0 42,0 44,0 46,0 48,0 50,0 52,0 54,0 56,0 58,0 60,0 62,0 64,0 66,0 67,2 k o n k ia n t h ic k n e s s 5 1 ,0 m lower sarmatian (volhynian) n1s1 lower sarmatian (volhynian) n1s1 middle sarmatian (bessarabian) n1s2 lower sarmatian (volhynian) n1s1 lower sarmatian (volhynian) n1s1 karaganian n1krg eh2 nm5 s he lls d et rit us a nd ra re s he lls o f s pi ra te lla k on ke ns is , a lv en iu s ni tid us , m ac tra s p. s he lls d et rit us sh el ls d et rit us an d ra re s m al l sh el ls o f c ar di um s p. – alvenius – ervilia – shells detritus– bivalvia– hydrobia– gastropoda– barnea be ds w ith p ho la di da e k o n k ia n t h ic k n e s s 4 ,2 m mayachka formation (n1mc)tarkhanian ? lamination clays aleurites sandstones cloddy clays sands limestones chemogenic limestones gravel and pebbles detritus break in sedimentation well 9 tymoshivka village well 6 soloviovka village well 20 leninske village well 8m melitopol town well 8z dohmarivka village 88,5 88,0 87,8 87,1 87,0 86,5 86,0 85,5 85,2 85,0 84,5 84,3 eh2 fo ra m in ife ra l as se m bl ag es m ol lu sc s as se m bl ag es sh el ls d et rit us ; r ar e h yd ro bi as p. a nd e . p us illa ; in te rla ye r o f s he lls o f t er re st ria l s pe si es (8 4, 784 ,3 m ) nm1 nm nm2 nm3 redeposited fauna e rv ili a p ho la di da e be ds w ith p ho la di da e 82,65 82,70 82,75 82,80 82,85 82,90 83,00 83,10 83,21 83,32 83,43 83,54 83,65 83,76 83,87 84,00 k o n k ia n t h ic k n e s s 1 ,7 8 m rumpled layer with redeposit fauna of chokrakian and karaganian ages nm1 nm mx eh1 fo ra m in ife ra l as se m bl ag es m ol lu sc s as se m bl ag es b ar ne a ervilia s he lls de tri tu s s he lls de tri tu s 85,0 86,0 88,0 89,0 90,0 87,0 k o n k ia n t h ic k n e s s 5 ,0 m the well was stopped nm4 eh1 eh1 nm eh1 nm4 mx fo ra m in ife ra l as se m bl ag es m ol lu sc s as se m bl ag es euryhaline sh el ls de tri tu s eh eh normal-marine molluscs assemblages nm s he lls de tri tu s be ds w ith er vi lia 90,0 91,0 93,0 94,0 95,0 92,0 96,0 97,0 99,0 100,0 98,0 k o n k ia n t h ic k n e s s 1 0 ,0 m fo ra m in ife ra l as se m bl ag es m ol lu sc s as se m bl ag es the well was stopped mx mx eh1 eh1 eh1 eh1 eh1 eh1 eh1 eh1 eh eh1 eh eh be ds w ith p ho la di da ebeds with ervilia and pholadidae beds with ervilia beds with pholadidae – sampling points the general (isohronous) foraminiferal assemblage for some wells foraminiferal assemblages with different paleoecological characteristic euryhaline assemblage and spirialis sp. eh spirialis eh spirialis mx eh spirialis ervilia barnea ervilia barnea ervilia barnea fo ra m in ife ra l as se m bl ag es m ol lu sc s as se m bl ag es eh2 nm3 nm1 nm4 figure 8. distribution of foraminiferal and molluscs assemblages in the konkian deposits of the studied wells. g eologia c roatica vernyhorova yuliia: biostratigraphy of the konkian (middle miocene of the eastern paratethys) deposits of southern ukraine based on foraminifera 143 ana djanelidze, q. minakovae ukrainica, q. ex gr. consob­ rina, q. pseudoangustissima, varidentella reussi sartaganica, triloculina inflata, globulina gibba, discorbis supinus, d. squa­ mulus (reuss), spirolina sp., florilus boueanus, nonion sp., ammonia ex gr. beccarii. it was determined in well 8z (87.8-87.0 m) in the eastern part of the northen black sea region (figs. 6, 8). this interval is characterized by dark grey viscous clays with aleurite powders grains on bedding planes. the numerous mollusc shells of barnea pseudoustjurtensis and fragments of ervilia pusilla trigonula and hydrobia sp. were found together with this foraminiferal assemblage (figs. 7, 8). these are beds with pholadidae (fig. 7) or kartvel beds (in the sense of merklin, 1953; muratov & nevesskaya, eds., 1986). assemblage nm3 is characterized by equal quantities of poorly preserved tests: hauerina podolica serova, hauerina sp. 1, hauerina sp. 2, discorbis sp. 1, discorbis? sp. 2. it was determined in well 8z (86.9-86.3 m) in the eastern part of the northern black sea region (figs. 6, 8). these deposits are characterized by interbeddings of greenish-light-grey aleurites and darker clays. the numerous mollusc shells of barnea pseudoustjurten­ sis, ervilia pusilla trigonula and single shells of hydrobia sp. were found together with this foraminiferal assemblage (figs. 7, 8). these are beds with ervilia and pholadidae (fig. 7) or the kartvel beds (in the sense of barg, 1969). assemblage nm4 is characterized by the dominant species: reussela spinulosa, spirolina austriaca orbigny, dendritina cf. haueri orbigny, borelis melo and subdominant species: varidentella reussi sartaganica, nonionella ventragranossa krasheninnikov, nonion tauricus, elphidium antonina krasheninnikov, elphidium sp. it was determined in two levels of well 6 (87.3-87.2 m; 85,8-85.0 m) in the eastern part of the northern black sea region (figs. 6, 8). these deposits are characterized by greenish-dark-grey dense clays. the numerous mollusc shells have been found together with this foraminiferal assemblage (figs. 7, 8). there are anadara turonica (dujardin), venerupis (polititapes) vitaliana (orbigny), plicati­ forma praeplicata (hilber), ervilia pusilla trigonula, obso­ letiforma lithopodolica ruthenica, retusa sp., natica millepunctata lamark. these are normal-marine molluscs assemblages (fig. 7) or sartagan beds (in the sense of merklin, 1953; muratov & nevesskaya, eds., 1986). assemblage nm5 is characterized by different abundances of foraminiferal tests in each sample without an obvious predomination of a particular species: quinqueloculina gracilis, q. guriana, bolivina floridana cushman, b. dilatata reuss, neobulimina elongata (orbigny), uvigerina gracilissima pobedina, fursenkoina schreibersiana (czjzek), guttulina aff. austriaca orbigny, discorbis kartvelicus, cassidulina sp. it was determined in well 20 (67.2-18.1 m) in the western part of the kerch peninsula (fig. 6, 8). these deposits are characterized by grey to light grey dense, thinly-laminated clays sometimes sandy, with aleurite powders on interbeddings. rare mollusc shells of limacina konkensis (zhizhchenko), alvenius nitidus, mactra sp., and shell detritus were found together with this foraminiferal assemblage (figs. 7, 8). in addition, many shells of barnea pseudoustjur­ tensis were found only in one part of the deposits (well 20: 54.745.7 m) and these are beds with pholadidae (fig. 7) or the kartvel beds (in the sense of merklin, 1953; muratov & nevesskaya, eds., 1986). assemblage eh1 is characterized by dominant species: po­ rosononion subgranosus (egger), elphidium macellum (fichtel & moll), ammonia ex gr. beccarii and subdominant species: florilus boueanus, q. aff. guriana, varidentella reussi sartaganica, discorbis sp., nonion tauricus, elphidium joukovi. it was determined in two wells: 9 (84.0-83.7 m); 8m (in several samples in interval 100.0-96.5 m) and on three levels of well 6 (88.5-87.5 m; 87.35-87.3 m; 86.6-85.8 m) in the eastern part of the northern black sea region (fig. 6, 8). these deposits are characterized by greenish-dark-grey clays (well 9); light-grey laminated clays with aleurite powders on interbeddings (well 8m: 96.5-98.8 m), light-grey with a greenish tinge fine-grained, sometimes clayey quartz sands (well 8m: 98.5-100.0 m ); interbeds of greenish-dark-grey dense clays and light-grey sandstones, with interbeds of light-grey quartz sands (well 6: 88.5-87.3 m, 87.35-87.3 m, 86.6-85, 8 m). different molluscs were found together with this assemblage (fig. 7, 8). rare mollusc shells of alvenius nitidus, er­ vilia pussila trigonula, venus sp. were found together with this foraminiferal assemblage in well 6 (88.5-87.3 m, 87.35-87.3 m) and in well 8 (96.2-93.8 m; 93.0-91.6 m; 91.1-90.0 m). these are euryhaline mollusc assemblages (fig. 7) or veselyanka beds (in the sense of merklin, 1953; muratov & nevesskaya, eds., 1986). also, many shells of barnea pseudoustjurtensis were found only in well 8 (100.0-97.8 m; 96.4-96.2 m). these are beds with pholadidae (fig. 7) or kartvel beds (in the sense of merklin, 1953; muratov & nevesskaya, eds., 1986). and also many shells of ervilia pussila trigonula and mollusc detritus were found in wells 9 and 6 (86.6-85.8 m). these are beds with ervilia and pholadidae (fig. 7) or kartvel beds (in the sense of barg, 1969). assemblage eh2 is characterized by the same species composition as assemblage eh1 but also comprises some tests of the early sarmatian species: elphidium reginum (orbigny), e. horridum, quinqueloculina consobrina sarmatica gerke, ar­ ticulina sp., entosolenia sp. this assemblage was determined in the upper part of the konkian deposits before the konkian/sarmatian boundary in well 8z (86.3-84.3 m) in the eastern part of the northern black sea region and well 20 (18.1-16.2 m) in the western part of the kerch peninsula (fig. 6, 8). it characterizes the final development stage of the konkian basin (vernyhorova, 2015a, b, 2016). these deposits are characterized by interbeds of greenish-light-grey aleurites and clays, bluish-lightgrey non-laminated carbonate clays at the top of the interval (well 8z); grey aleuritic, massive, thick-laminated clays with aleurite powders on interbeddings (well 20). rare mollusc shells of hydrobia sp., ervilia pusilla trigonula, avenius nitidus and some terrestrial species in well 8z and shells detritus with scarce small shells of cardium sp. (well 20) were found together with this assemblage (figs. 7, 8). the konkian age of deposits with this assemblage was confirmed in well 8z by molluscs and ostracods (prisyazhnyuk et al., 2007). assemblage mx is characterized by equal abundance of large tests of euryhaline species: porosononion subgranosus, el­ phidium aculeatum, ammonia ex gr. beccarii and small tests of stenohaline species: bolivina dilatata, neobulimina elongata, uvigerina gracilissima, fursenkoina schreibersiana, guttulina aff. austriaca, reussela spinulosa, discorbis sp.1, cassidulina sp. this assemblage was determined in different levels of three wells: 9 (83.7-83.0 m); 6 (87.0-86.6 m); 8m (96,75-96,7 m; 93,593,45 m) in the eastern part of the northern black sea region. these deposits are characterized by light-grey carbonate dense clays (well 9); black with a greenish tinge dense clays (well 6); light-grey laminated clays with aleurite grains on interbeddings (well 8m: 96.75-96.7 m) light-grey fine-grained, carbonate sandstones (well 8m: 93.5-93.45 m). different molluscs were found together with this assemblage (fig. 7, 8). namely, rare mollusc shells of alvenius nitidus, ervilia pusilla trigonula, cardium sp., venus sp. and limacina sp. (mixed mollusc assemblage) were g eo lo gi a c ro at ic a geologia croatica 71/3144 found in well 8m; the numerous molluscs shells of barnea pseu­ doustjurtensis (beds with pholadidae – in the sense of merklin, 1953; muratov & nevesskaya, eds., 1986) were found in a thin layer in well 9 (83.5-83.32 m); shells detritus were found in well 6 and well 9 (83.7-83.5; 83.32-83.0 m). 5.2. biostratigraphic reconstruction of the konkian deposits of the southern ukraine based on foraminifera shallow-water konkian deposits of the eastern black sea region (tymoshivka formation) contain several foraminiferal assemblages with different taxonomic composition and palaeoecological characteristics. they occur together with different mollusc assemblages (figs. 7, 8). normal-marine foraminiferal assemblages (nm1-nm4) are accompanied by adequate mollusc assemblages (single levels of wells 8z; 9; 6) and also by beds with pholadidae and by beds with ervilia and pholadidae (two levels of well 8z). the euryhaline foraminiferal assemblages (eh1; eh2) are accompanied by euryhaline mollusc assemblages (different levels of wells 6; 8m) and also by beds with pholadidae and by beds with ervilia (different levels of wells 9; 6; 8m). a mixed foraminiferal assemblage (mx) is accompanied by mixed mollusc assemblages (two levels of well 8m) and also by beds with pholadidae (single level of well 9). also, some levels with different foraminiferal assemblages are composed only of the detritus of mollusc shells (different levels of wells 8z; 9; 6). all these foraminiferal assemblages as well as mollusc assemblages have different and irregular positions in the konkian deposits of the various wells. a similar sequence of such assemblages was found in the konkian sections of shallow-water deposits in other areas of the northern black sea region (hladkivka formation, novokakhovka formation) and in the crimean peninsula (mekenziev strata, tarkhankut formation, novokakhovka formation) (e.g. didkovskiy, 1959; barg, 1969, 2008; ivanova, 2012; vernyhorova, 2015b, 2016, etc.). the distribution of konkian foraminiferal assemblages in more deep-water deposits of the kerch peninsula is significantly different from deposits of the coeval shallow-water sediments of the northern black sea region and the crimean peninsula. the lower and much thicker part of these deposits contains a normalmarine foraminiferal assemblage with a predominance of stenohaline species (figs. 7, 8). a significant rearrangement of the species composition is observed only in the upper part of the konkian deposits below the konkian/sarmatian boundary. these deposits contain a depleted foraminiferal assemblage with a predominance of euryhaline species and a minor admixture of the early sarmatian species. the kerch foraminiferal assemblages are similar to those from the relatively deep-water konkian sediments of the taman peninsula and the western ciscaucasus (e.g. bogdanowicz, 1965; golovina et al., 2009; vernigorova et al., 2006; popov et al., 2016; palcu et al., 2017). the analysis of foraminiferal assemblages with different species composition and palaeoecological characteristics revealed a common assemblage (nm1) in three wells (8z; 9; 6) of the eastern black sea region (figs.7; 8). marine molluscs, bryozoans and echinoid radiole were also found together with this assemblage. small distances between these wells (43 and 17 km accordingly – see fig. 6) allow consideration of these deposits with identical fauna as an isochronous level. this level was used as a benchmark for stratigraphic correlation, for identification of hiatuses and also for the reconstruction of palaeoenvironmental conditions during konkian time in the research area. namely, if we assume that the hm1 assemblage in different wells was formed west east h i a t u s h i a t u s h i a t u s h i a t u s h i a t u s k on ki an s ar m at ia n lo w er k ar ag an ia n m id d le m io c e n e c ho kr ak ia n ta rk ha ni an mayachka formation (age is under discussion because fauna is absent) mayachka formation (age is under discussion because fauna is absent) ? hryhoriivka formationkrasnoperekopsk formation t y m o s h i v k a f o r m a t i o n euryhalinenormal-marinefaunal assemblages: beds with ervilia and pholadidaemixed the legend of the rocks is shown at the fig. 8 figure 9. palaeoecological and stratigraphic reconstruction of the middle miocene deposits of the eastern black sea region. g eologia c roatica vernyhorova yuliia: biostratigraphy of the konkian (middle miocene of the eastern paratethys) deposits of southern ukraine based on foraminifera 145 contemporaneously then deposits with this assemblage represent a single biostratigraphic level and a marker for the stratigraphic evaluation of other horizons. the final phase of development of the konkian basin was determined in the upper part of well 8z (the eastern black sea region) and well 20 (the kerch peninsula) (figs. 7, 8) based on the presence of the special foraminiferal assemblage (eh2) in these deposits. combining the data on changes of foraminiferal and molluscs assemblages with other bioand lithostratigraphic data concerning the middle miocene sediments of the investigated area (e.g. arkhanguelsky, ed., 1940; didkovskiy, 1959; molyavko, 1960; barg, 1969, 2008; prisyazhnyuk et al., 2007; vernigorova, 2008, 2009, 2012; vernigorova et al., 2009; vernyhorova, 2015b; 2016) allowed the creation of palaeoecological and stratigraphic reconstruction of the middle miocene sediments in the eastern black sea region (fig. 9). 6. сonclusions the study of spatial and temporal changes of foraminiferal assemblages in the konkian deposits of southern ukraine indicate that the shallow-water basin of the eastern black sea region and the more deep-water basin of the kerch peninsula had different models of development during most of the konkian period. two foraminiferal assemblages with different palaeoecological characteristics in the studied deposits of the kerch peninsula indicate two successive development phases of the relatively deep-water konkian basin of this area. during the first, longer part of the konkian, relatively stable marine conditions predominated, while the late period of existence of this palaeobasin is characterized by a sharp change to euryhaline conditions. changes in foraminiferal assemblages in relatively deeper-water konkian deposits of the kerch peninsula and the ciscaucasus are similar. this indicates that basins with such types of sediments in the eastern paratethys had a similar pattern of development during the konkian. many irregular vertical and lateral changes of foraminiferal assemblages with different palaeoecological characteristics and hiatuses observed in the shallow-water konkian deposits of the eastern black sea region indicate that the palaeobasin in this area was influenced by frequent and abrupt changes in environmental conditions during most of the konkian. palaeoecological and lithological characteristics of the konkian deposits of the eastern black sea region are similar to those of other shallow-water coeval deposits of the southern ukraine, and it can be concluded that the development of the entire northern black sea region and most of the crimean peninsula were similar during this time period. the late development phase of the konkian was the same in both shallow-water deposits of the eastern black see region and more deep-water deposits of the kerch peninsula deposits. this phase was characterized by the presence of similar euryhaline assemblages of konkian foraminifera (and molluscs) with a small admixture of the early sarmatian species. acknowledgment many thanks to v.a. prysyajnyuk and o. anistratenko (igs nas of ukraine, kyiv, ukraine) for helping in the identification of species of some molluscs; i.l. knyazkova (geol ogist, volnovakha, ukraine), l.a. fikolina (geologist, si mferopol, ukraine), for helping with the lithological description of the wells; t. ryabokon (igs nas of ukraine, kyiv, ukraine) a. bratishko (luhansk taras shevchenko national university, starobelsk, ukraine) for discussion of some scientific issues. references andrusov, n.i. (1917): konskiy gorizont (foladovie plasty) [konkian horizon (pholada beds) – in russian].– proceedings of the geological and mineralogical museum, 2/ii, 167–261. arkhanguelsky, a.d., blohin, a.a., menner, v.v., osipov, s.s., sokolov, m.i. & chepikov, k.r. (1930): kratkiy ocherk geologicheskogo stroyeniya i neftyanykh mestorozhdeniy kerchenskogo poluostrova [brief sketch of the geological structure and oil fields of the kerch peninsula – in russian].– proceedings of the main of geological exploration, 13, 142 p. arkhanguelsky, a.d. (ed.) (1940): stratyhrafiya sssr. t. xii. neohen sssr [stra­ tigraphy of ussr. vol. 10. neogene of the ussr – in russian].– moskow, leningrad, 688 p. barg, i.m. (1969): ervilievye i foladovye kompleksy v sredne-miotsenovykh otlozheniyakh yuzhnoi ukrainy [ervilia and pholas assemblages in the middle miocene de­ posits of the southern ukraine – in russian].– bulletin of moscow society of naturalists. geological series, 4/23, 78–83. barg, i.m. (1993): biostratigrafiya verkhnego kaynozoya yuzhnoy ukrainy [biostratigraphy of the upper cenozoic of the southern ukraine – in russian].– dnepropetrovsk, edition by dgu, 196 p. barg i.m. (2008): o pravomochnosti ispolzovaniya stratigraficheskikh terminov ”varnenskiye“ i ”karvelskiye“ sloi v konkskom regioyaruse vostochnoho paratetisa [ap­ propriate use of the stratigraphical terms “varna beds” and “karvel beds” in the konkian regional stage of the eastern parathetys – in russian].– collection of the institute of geological sciences of nas of ukraine, kyiv, 437–442. barg, i.m. & ivanova, t.a. (2000): stratigrafiya i geologicheskoye razvitiye ravninnogo kryma v miotsene [stratigraphy and geological development of the crimea in the miocene – in russian].– stratigraphy. geological correlation, 8/3, 83–93. barg, i.m. & stepaniak, y.d. (2003): stratigrafiya i geologicheskoye razvitiye ravninnogo kryma i kerchenskogo poluostrova v miotsenovuyu epokhu [stratigraphy and geological development of the crimea and kerch peninsula in the miocene epoch – in russian].– dnepropetrovsk, 170 p. bogdanowicz, a.k. (1952): miliolody i peneroplidy [miliolidae and peneropliidae – in russian].– proceedings of vnigri, 64, 338 p. bogdanowicz, a.k. (1965): stratigraficheskoe i fatsialnoe raspredelenie foraminifer v miotsene zapadnoho predkavkaz’ya i voprosy ikh genezisa [stratigraphic and facies distribution of foraminifera in the miocene of western ciscaucasia and questions of their genesis – in russian]. – proceedings of the krasnodar branch of the all-union oil and gas research institute, 16, 300–350. bondar, o.v. (2004): stratyhrafyya konkskykh otlozhenyy yuzhnoy ukrayny po ostrakodam [stratigraphy the konkian deposits of southern ukraine according to ostra­ cods – in russian].– problems of phanerozoic stratigraphy of ukraine: scientific papers of the institute of geological sciences of ukraine, kyiv, 172–174. bratishko, a., schwarzhans, w., reichenbacher, b., vernyhorova, y. & corić, s. (2015): fish otoliths from the konkian (miocene, early serravallian) of mangyshlak (kazakhstan) – testimony of an early endemic evolution in the eastern paratethys.– palaontologische zeitschrift, 89/4, 839–889. doi: 10.1007/s12542-0150274-4 bugrova, e.m., gladkov, v.i., dmitrieva, t.v., nevzorova, l.s. & sokolov, b.c. (2005): prakticheskoe rukovodstvo po mikrofaune, tom 8: foraminifery kainozoya [guidebook of microfauna, volume 8: cenozoic foramini­ fera – in russian]. – proceedings of vsegei, 324 p. buleishvili, d.a. (1960): geologiya i neftegazonosnost mezhgornoy vpadiny vostochnoy gruzii [geology and petroleum the intermountain depressions in eastern geor­ gia – in russian].– gostoptehizdat, moskow, 240 p. buriak, v.n. (1965): o stratigraficheskom podrazdelenii neogenovykh otlozheniy zapadnogo predkavkaz’ya [about stratigraphic subdivisions of neogene sediments of the western ciscaucasia – in russian].– proceedings of kfvnii, 16, 300–350. chikovani, a.a. (1964): sredniy miotsen. geologiya sssr. gruzinskaya sssr. geologicheskoye opisaniye. tom 10 [middle miocene. geology of the ussr. georgian soviet union. geological description. volume 10 – in russian].– nedra, moskow, 1/10, 655 p. didkovskiy, v.ya. (1959): pro mikrofaunu vidkladiv konkskoho horyzontu ursr, [about microfauna from deposits of the konkian horizon of ukrssr – in ukrainian].– reports of the academy of sciences of the ussr, 4, 412–416. didkovskiy, v.y. & kulichenko, v.g. (eds.) (1975): stratyhrafiya ursr. t. 10. neohen [stratigraphy of ukrssr. vol. 10. neogene – in ukrainian].– naukova dumka, kyiv, 270 p. djanelidze, o.i. (1970): foraminifery nizhnego i srednego miotsena gruzii [foraminif­ era from the late and middle miocene of georgia – in russian].– metsniereba, tbilisi, 172 p. gozhyk, p.f. (ed.) (2012): stratyhrafichnyy kodeks ukrayiny [stratigraphic code of ukraine – in ukrainian].– kyiv, 66 p. golovina, l.a., vernigorova, yu.v. & beluzhenko, e.v. (2009): novyye dannyye po mikropaleontologii konkskikh otlozheniy zapadnogo predkavkazya [new data about micropaleontology from the konkian deposits of western ciscaucasia – in russian].– fossil flora and fauna of ukraine: paleontological and stratigraphic aspects: proceeding of the institute of geological sciences of the nas of ukraine, kyiv, 311–321. g eo lo gi a c ro at ic a geologia croatica 71/3146 hilgen, f.j., lourens, l.j., van dam, j.a., beu, a.g., boyes, a.f., cooper, r.a., krijgsman, w., ogg, j.g., piller, w.e. & wilson, d.s. (2012): the neogene period. the geologic time scale, 1–2, 923–978. doi: 10.1016/b978-0444-59425-9.00029-9 ilyina, l.b. (1993): opredelitel morskih srednemiotsenovih gastropod yugo-zapadnoy evrasii [handbook for identification of the marine middle miocene gastropods of southwestern eurasia – in russian].– proceedings of the paleontological institute, 255, 1–151. ilyina, l.b. (2000): on the regional konkian stage (middle miocene) in the eastern paratethys.– stratigraphy. geological correlation, 8/4, 59–64. ivanova, t.a. (2012): foraminifery konkskogo regioyarusa yuzhnoy ukrainy: etapnost razvitiya, stratigraficheskoye znacheniye [foraminifera from the konkian regional stage of southern ukraine: stages of evolution, stratigraphic significance – in russian].– proceedings of the 34th session of the paleontological society of nas of ukraine, kyiv, 95–96. koiava, k., mosar, j., kvaliashvili, l. & mauvilly, j. (2016): about konkian/ sarmatian boundary of georgia based on foraminifera.– swiss geoscience meeting: platform geosciences, swiss academy of science, scnat, 224–225. krasheninnikov, v.a. (1959): foraminifery. [foraminifera – in russian].– in: zhizhchenko, b.p. (ed.): atlas of the middle miocene fauna from north caucasus and crimea – gostoptehizdat, moskow, 15–103. krasheninnikov, v.a., basov, i.a. & golovina, l.a. (2003): vostochnyy paratetis: tarkhanskiy i konkskiy regioyarusy [the eastern paratethys: tarkhanian and konkian regional stages – in russian].– nauchnyy mir, moskow, 193 p. liverovskaya, e.v. (1935): fauna konkskogo gorizonta gory dubrovoy (severnyy kavkaz) [fauna of the konkian horizon of mountains dubrovaya (north caucasus) – in russian].– proceedings of petroleum geological prospecting institute, a/34, 35 p. liverovskaya, e.v. (1960): tretichnyye otlozheniya mangyshlaka [tertiary sediments of mangyshlak – in russian].– gostoptehizdat, moskow, 142 p. maissuradze, l., koiava, k., kvaliashvili, l. & spezzaferri, s. (2014): biodiversity, evolution and biostratigrafic significance of konkian foraminifers of euxine-caspian basin of eastern paratethys.– proceedings of the georgian national museum, natural sciences and prehistory section, 6, 9–22. merklin, r.l. (1953): etapy razvitia konkskogo basseina v miocene na uge sssr [the stages of konkian basin development in the miocene of the southern ussr – in russian].– bulletin of the moscow society for the sources of nature, department of geology, 28/3, 89–91. molyavko, g.i. (1960): neohen pivdnya ukrayiny [neogene of the south of ukraine – in ukrainian], edition of an ursr, kyiv, 208 p. muratov, m.v. & nevesskaya, l.a. (eds.) (1986): stratigrafia sssr. neogenovaya sistema. polutom 1 [stratigraphy of the ussr. neogene system. semivolume 1 – in russian].– nedra, moskva, 419 p. nevesskaya, l.a., goncharova, i.a., paramonova, n.p., popov, s.v., babak, e.v., bagdasaryan, k.g. & voronina, a.a. (1993): opredelitel miotsenovih dvustvorchatih molluskov yugo-zapadnoy evrazii [handbook for identifi­ cation of the bivalvia of southwestern eurasia – in russian].– proceedings of the paleontological institute, 247, 412 p. nevesskaya, l.a., kovalenko, e.i., beluzhenko, e.v. popov, s.v., goncharova, i.a., danukalova, g.a., zhidovinov, y.ya., zaitsev, a.v., zastrozhnov, a.c., pinchuk, t.n., illina, l.b., paramonova, n.p., pismennaya, n.s. & hondkarian, s.o. (2005): regionalnaya stratigraficheskaya skhema neogena yuga yevropeyskoy chasti rossii. [regional stratigraphic scheme of the neogene of the southern european part of russia – in russian].– stratigrafiya, regionalnaya geologiya i tektonika, moskow, 47–59. nosovskiy, m.f. (1960): stratigrafiya mezokaynozoyskikh otlozheniy belozerskogo zhelezorudnogo mestorozhdeniya (ussr) [stratigraphy of mesozoic­cenozoic sedi­ ments from belozersky iron ore deposits (ukraine) – in russian].– geology and mineralogy of sedimental formations of the ukrainian ssr. scientific notes of dnepropetrovsk university, 59, 73–90. osipov, s.s. (1927): o konkskom gorizonte severnogo kavkaza i kerchenskogo poluostrova [about the konkian horizon of the north caucasus and the kerch peninsula – in russian].– bulletin of the moscow society of naturalists. department of geology, 5/3–4. new series, 35, 371–376. palcu, d.v., golovina, l.a., vernyhorova, y.v., popov, s.v. & krijgsman, w. (2017): middle miocene paleoenvironmental crises in central eurasia caused by changes in marine gateway configuration.– global and planetary change, 158, 57–71. doi: 10.1016/j.gloplacha.2017.09.013 peryt, t.m. (2006): the beginning, development and termination of the middle miocene badenian salinity crisis in central paratethys.– sedimentary geology, 188, 379–396. doi:10.1016/j.sedgeo.2006.03.014 popov, s.v., rostovtseva, yu.v., fillippova, n.yu., golovina, l.a., radionova, e.p., goncharova, i.a., vernyhorova, yu.v., dykan, n.i., pinchuk, t.n., iljina, l.b., koromyslova, a.v., kozyrenko, t.m., nikolaeva, i.a. & viskova, l.a. (2016): paleontology and stratigraphy of the middle – upper miocene of taman peninsula. part 1. description of key-sections and benthic fossil groups.– paleontological journal, (supplement), 50/10, 168 p. doi: 10.1134/s0031030116100014 prisyazhnyuk, v.a., kovalenko, v.a.& lyuleva, s.a. (2007): o konkskykh otlozhenyyakh yuga ukrainy [about the konkian sediments of the southern ukraine – in russian].– paleontological research in ukraine: history, current state and perspectives, kyiv, 298–305. sokolow, n. (1899): sloi s venus konkensis na reke konke [venus konkensis beds at the konka river – in russian].– memores du comite geologique, 9/5, 1–96. starin, d.a. (2012): osobennosti stratigraficheskogo deleniya konkskogo regioyarusa borisfenskogo zaliva (yuzhnaya ukraina) po faune mollyuskov [features of stratig­ raphy the konkian regional stage of borysthenian bay (southern ukraine) according to fauna of molluscs – in russian].– proceedings of the 34th session of the paleontological society of nas of ukraine, kyiv, 99–100. sudo, m.m. (1961): ob etapakh razvitiya karaganskogo basseyna i obyeme karaganskogo gorizonta [about the stages of development of the karaganian basin and the volume of the karaganian horizon – in russian]. – reports of the academy of sciences of the ussr, 139/6, 1442–1444. teslenko, yu.v. (ed.) (1997): stratyhrafichnyy kodeks ukrayiny [stratigraphic code of ukraine – in ukrainian].– kyiv, 39 p. varentsov, m.i. (1950): geologicheskoe stroenie zapadnoi chasti kurinskoi depressii [geological structure of the western part of the kura depression – in russian].– akad. nauk sssr, moscow-leningrad, 258 p. vereshagin, v.n. & mironova, l.v. (1982): stratigraficheskiy slovar sssr. paleogen, neogen, chetvertichnaya sistema [stratigraphic dictionary of the ussr. paleo­ gene, neogene, quaternary – in russian].– nedra, leningrad, 616 p. vernigorova, yu.v. (2008): osobennosti raspredeleniya foraminifer i nekotoryye voprosy stratigrafii konkskikh otlozheniy severnogo prichernomor’ya [the distribution of foraminifers and some problems of stratigraphy the konkskian deposits of the northern black sea coast – in russian].– biostratigraphic fundamentals of creating the stratigraphic schemes of the fanerozoic of ukraine, kyiv, 212–219. vernigorova, j.v. (2009): karagansky i konksky regioyarusi vostochnogo paratetisa: voprosi ih obyoma i stratigraficheskoy samostoyatelnosti [the karaganian and konki­ an regional stages of the eastern paratethys: problems of their stratigraphic range and validity – in russian].– geologichniy zhurnal, 2, 34–47. vernigorova, yu.v. (2012): raspredeleniye foraminifer i mollyuskov v konkskikh otlozheniyakh vostochnogo prichernomoriya [distribution of foraminifera and molluscs in the konkian sediments of the eastern black sea region – in russian].– proceedings of the 34th session of the paleontological society of nas of ukraine, kyiv, 97–98. vernigorova, yu.v., golovina, l.a.& goncharova, i.a. (2006): k kharakteristike konkskykh otlozheniy tamanskoho poluostrova [the characterization of the konkian sediments of the taman peninsula – in russian].– problems of paleontology and biostratigraphy proterozoic and phanerozoic of ukraine: scientific papers of igs nas of ukraine, kyiv, 231–242. vernigorova, yu.v., knyazkova, i.l. & kovalenko, v.a. (2009): razrez miotsena severnogo borta prichernomorskoy vpadiny [the miocene section of the northern edge of the black sea depression – in russian].– geological journal, 3/328, 41–50. vernigorova, yu.v., fikolina l.a. & obsharskaya n.n. (2012): strukturnofatsialnoye rayonirovaniye neogenovykh otlozheniy kerchenskogo poluostrova [structural and facies zonation of the neogene sediments of the kerch peninsula – in russian].– geological journal, 3, 74–94. vernyhorova, yu.v. (2014): litoi biofatsialniye osoblyvosti neohenovykh vidkladiv kerchenskoho pivostrova [lytho­ and biofacies features of the neogene deposits of the kerch peninsula – in ukrainian].– collection of scientific work of the institute of geological sciences of nas of ukraine, 7, 126–171. vernyhorova, yu.v. (2015a): kriterii stratigraficheskogo raschleneniya konkskikh otlozheniy vostochnogo paratetisa po mollyuskam i foraminiferam [the criteria of the konkian deposits stratigraphy of the eastern paratethys based on molluscs and fo­ raminifera – in russian].– geological journal, 4, 77–86. vernyhorova, yu.v. (2015b): stratyhrafichna skhema neohenovykh vidkladiv prychornomoriya ta prylehloyi chastyny ukrayinskoho shchyta [stratigraphic scheme for the neogene deposits of the nothern black sea region and adjacent part of the ukrainian shield – in ukrainian].– geology and ore content of ukraine, 1/1, 81–124. doi: 10.15421/121510. vernyhorova, yu.v. (2016): stratyhrafichna skhema neohenovykh vidkladiv krymsʹkoho pivostrova [stratigraphic scheme for the neogene deposits of the crimea peninsula – in ukrainian].– geology and ore content of ukraine, 2/1, 59-106. doi: 10.15421/121606 zhamoida, a.i. (ed.), (1977): stratigraphicheskiy kodeks sssr [stratigraphic code of the ussr – in russian].– leningrad, 80 p. zhgenti, e.m. (1976): lyutetsiidy srednego miotsena, ikh evolyutsiya i stratigraficheskoye znacheniye [middle miocene luteciidae, their evolution and stratigraphic significance – in russian].– metsniereba, tbilisi, 177 p. zhgenti, e.m. & maissuradze, l.s. (2016): karaganskiy, kartvekmskiy i konkskiy regioyarusy gruzii. istoriya razvitiya molluskov i foraminifera i ikh stratigrafocheskoe znachenie [the karaganian, kartvelian and konkian deposits of georgia. the his­ tory of development and stratigraphical significans of molluscs and foraminifera – in russian].– tbilisi, 91 p. zhizhchenko, b.p. (1937a): o vozraste i faune foladovykh sloyev [about the age and fauna of folada bads – in russian].– materials of the miocene of the northern caucasus, 6/1, 81–117. zhizhchenko, b.p. (1937b): k izucheniyu fatsiy 2-go sredizemnomorskogo yarusa [to study the facies of the 2nd of the mediterranean stage – in russian].– materials of the miocene of the northern caucasus, 6/1, 133–200. 2018 | 71/2 | 97–104 | 5 figs. | 4 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction within the water resources, groundwater constitutes a strategic element that fulfills several functions: it contributes to the base flow of surface water streams, maintenance of groundwater de­ pendant ecosystems and is an important source to satisfy human, industrial and agricultural needs. for some time, fresh surface water has been a scarce resource, largely due to increasing popu­ lation in cities and rising living standards, agricultural and indus­ trial needs increasingly demand water, especially groundwater, since the surface water is susceptible to contamination and scarce in prolonged droughts. it is estimated that approximately half of the world population depends on groundwater for human con­ sumption (wwap, 2016), which leads to a greater interest in un­ derstanding the resource in order to facilitate its adequate ma­ nagement. knowledge of the underground water resource is based on the collection of information, with the purpose of schematizing a conceptual hydrogeological model for a study area that allows the geometry and the physical characteristics of the territory to be understood. this includes the identification and delimitation of surface and in­depth hydrogeological units, determination of sources, areas and calculation of recharge, definition of under­ ground flow trends, knowledge of hydraulic properties, quality assessment and knowledge of intrinsic vulnerability. however, physical, chemical and biological characterization as support for water governance in a hydrogeological system of colombia juliana valencia ossa1, teresita betancur1, jhon duque1, angel cardona1, laura pineda1, pedro villegas2, vanessa paredes2 and carlos molano3 1 universidad de antioquia, medellín, colombia; (juliana.ossav@udea.edu.co) 2 corporación para el desarrollo sostenible de urabá-corpouraba, apartadó, colombia 3 universidad de los andes, bogotá, colombia doi: 10.4154/gc.2018.10 abstract understanding the physical, chemical and biological system is an indispensable precondition to addressing groundwater management. this understanding is based on conceptual hydrogeological models, which contain different interpretations and their validity is checked through the application of specific research techniques (numerical modelling, hydrochemistry, isotope hydrology, process evaluation and biological functions). this paper describes the experience carried out by an academic team that, together with entities responsible for the protection of water resources, established strategic alliances to improve the knowledge of the hydrogeological system, providing new elements for governance. this study was carried out in the urabá antioqueño zone, located north-west of colombia. a complex aquifer system is located in the region, characterized by a series of permeable, semi-permeable and impermeable layers. in such a layered aquifer the determination of the physical, chemical and biological characteristics of the layers and their management are a challenge for researchers because groundwater represents a strategic resource for supplying the population and developing economic activities. starting from the conceptual hydrogeological model, multiscale numerical modelling exercises have been carried out, enabling the characterization of local, intermediate and regional flow systems. in addition, by determining the natural background level, the concentration ranges of chemical compounds from natural sources were obtained, in order to detect future changes in water quality. it was also possible to examine the stygofauna, which allowed the recognition of different types of organisms (stygobits, stygophiles and stygoxens) associated with underground ecosystems. these scientific elements serve as a support for the management instruments such as the groundwater management plan that is important for water governance, ensuring its future sustainability. all this knowledge and research progress should always seek to improve the management and generation of policies on the sus­ tainability of this resource, in order to move towards better water governance (ministerio de ambiente y desarrollo sostenible, 2014). this paper presents the hydrogeological advances, taking into account the physical, chemical and biological characteristics of the hydrogeological system of the gulf of urabá in colombia, which were carried out in the framework of 4 master’s studies. these studies aimed to determine and promote responsible col­ lective actions that would ensure the short, medium and long term socially sustainable use of the water resources for the benefit of the community and dependent ecosystems. the objective of this work is to promote the integration of different fields of research in hydrogeology, which support and complement the hydrogeological conceptual model of an aquifer system, taking into account the most relevant aspects, in terms of hydrodynamic behaviour, hydrogeochemical conditions and the natural chemical background and biological aspects through the identification of stygofauna. the importance of this work in this area of colombia is that the groundwater allows the production of bananas (irrigation and washing of the fruit, which represent about 75% of the total de­ mand for groundwater) in an area about 320 km2 that is the main article history: manuscript received january 16, 2018 revised manuscript accepted june 06, 2018 available online june 21, 2018 keywords: layered aquifer, groundwater management, conceptual hydrogeological models, sustainability g eo lo gi a c ro at ic a geologia croatica 71/298 source of employment and income of the region. groundwater is the main source of domestic water supply for 18 rural communi­ ties and two of the four urban headwaters (which represents about 15% of the total demand for groundwater), making it a strategic resource that must be protected to guarantee the future supply of water for both human supply and for the development of eco­ nomic activities in the region. 2. description of the study area this research was carried out in the urabá subregion of antio­ quia, located in the most northerly corner of south america that coincides with colombia, in the department of antioquia. it is located between coordinates 8°10’35 “n, 7°31’27”s, -76°49’26” w, and -76°33’13”e, with an approximate area of 1.206 km² (fig. 1). the average air temperature in the region is 28 °c and the relative humidity is of the order of 85.9%, it also presents an ave rage annual precipitation between 2.100 mm/year and 3.800 mm/year and is characterized by a rainy season from april to december and a dry period between january and march. the hydrogeological system corresponds to an aquifer with multilayer characteristics (figure 2 & table 1). this type of sys­ tem consists of an alternating series of permeable, semi-perme­ able and impermeable layers. this knowledge was obtained from a detailed hydro stratigraphic correlation exercise using 258 drill­ ing logs, 202 vertical electrical surveys and 107 well electrical records. the system was hydraulically characterized by 158 pumping tests and with information from a piezometric monito­ ring network with quarterly sampling regime since 1998 cor­ pouraba & universidad de antioquia (2014) & duque et al. (2016). figure 1. zone of study with description of the modelling scales, sampling points with stygofauna and points of hydrogeochemical assessment. g eologia c roatica ossa et al.: physical, chemical and biological characterization as support for water governance in a hydrogeological system of colombia 99 according to the results of the water balance obtained by corpouraba & universidad de antioquia (2014), the average recharge in the study area is 270.9 mm/year. 3. materials and methods this research started from the setup of the conceptual model and some physical aspects of the hydrogeological system. for the cal­ culation of the groundwater supply, favourable areas for recharge were taken into account in which the upper levels of the aquifer system are composed of sands and gravels. in addition, to four stations, the water balance was calculated, considering dry year scenarios. these stations record the evaporation data, or are close to the stations with data record of the evaporimeter tank and flow. in addition, the location of the space was taken into account, seeking a better representation of the entire study area, establishing areas of influence through the thiessen polygons. on the other hand, the demand for groundwater was calculated from the information collected from the databases existing at the environ­ mental authority of the zone (corpouraba). it took into ac­ count the groundwater points and the current concession volume for abstraction points that are legalized along with their pumping regime. the characterization of the terrestrial cover corresponded to level 2, according to the nomenclature exposed by the co­ rine land cover clc methodology. results come from the re­ port on the semi-detached survey of land cover for the depart­ ment of antioquia, carried out by igac & gobernación de antioquia (2007), at a scale of 1:25.000. the piezometric analysis was performed taking into account the modelling of pi­ ezometric surfaces for the average dry season and rainfall, in or­ der to visualize trends in the underground flow dynamics. in addition, in order to more accurately represent this dy­ namic in a better way, a multi-scale (regional, intermediate and local) numerical modelling exercise (joyce et al., 2014) was car­ ried out in permanent and transient state to identify the flow sys­ tems present in the aquifer using the modelling software ground­ water vistas ® (environmental simulations incorporated 2015). this is a graphical interface of the modflow model, and sim­ ulated the ground-water flow using a block-centered finite-differ­ ence approach harbaugh & mcdonald (1996), where the model at the regional level provides the boundary and initial con­ ditions of the intermediate model and these in turn the local model. for the three models, the following conditions have been established: i) for the regional model that completely covers the study area, 100m x 100m cells were defined and three layers were con­ structed for an area of 1,206 km2. ii) for the intermediate model, information was collected from 73 drilling registers, 42 vertical electrical drills and 1 well electrical log, 20m x 20m cells were defined in an area of 123 km2, and five layers were constructed to represent the heteroge­ neity of the geometry. iii) for the local model with an area of 25 km2, 10m x 10m cells were defined and seven layers were constructed, with infor­ mation from 22 drilling logs, 8 vertical electrical probes and 1 well log. in all cases the following boundaries were considered and incorporated in groundwater vistas ®: river, general head boundary, well and drain to represent the wetlands. in the re­ gional model the constant head border was additionally used to figure 2. the multi layered aquifer hydrogeological system of the gulf of urabá. table 1. multi layered aquifer properties. property min max mean hydraulic conductivity k (m/day) 0.2 28.3 6.10 transmissivity (m2/day) 1.0 1840.0 145.7 thickness (m) 3 300 147.9 depth to groundwater table (m) 0.3 42.0 5.1 specific discharge (l/s/m) 0.05 13.6 1.5 g eo lo gi a c ro at ic a geologia croatica 71/2100 represent the gulf. the hydraulic conductivity (k) was calibrated according to data of pumping tests performed in the study area. taking into account the hydroclimatological characteristics of urabá for the transient calibration, three periods of stress were defined: the first between december 2010 and march 2011, the second between april and september 2011 and the third between october and november of 2011. the initial conditions for the modelling in transient state were taken from the model in cali­ brated permanent state. the initial recharge values applied to the model were different depending on the textural characteristics of the first layer three recharge zones were defined (clays, sands and gravels). the calibration was performed using the pest auto­ matic calibration module incorporated into the groundwater vis­ tas software. in addition, sensitivity analyses were conducted to evaluate the response of the piezometric levels and the mass bal­ ance from the controlled modification of hydraulic properties and boundary conditions (general head boundary, rivers and drain). the knowledge of the chemical characteristics of the system was acquired through the determination of natural chemical background levels, which according to edmunds et al. (2003) and shand et al. (2007) correspond to the concentration of a particular element, species or chemical composition of ground­ water present in solution that is derived from natural sources: geological, biological or atmospheric. for application of this study, the shallow and deep water bodies were separated: the depth of shallow levels was less than 30m and the deep levels were greater than 30m, samples with a balance error higher than 15% were discarded, with 69 samples for shallow and 262 sam­ ples for the deep level. in addition the analytical quality of the chemical analysis data was verified with the ionic relations pro­ posed by hounslow (1995). the sampling protocol followed is described in greater detail in ossa & betancur (2018). furthermore, in order to determine higher concentrations of the natural chemical background, the 90 and 95 percentiles were used based on the amount of information on each parameter, (90 for less than 60 samples and 95 for more than 60 samples). sam­ ples with a concentration of no3 ­ above 10 mg/l were previously discarded. for the biological characterization the organisms be­ longing to the stygofauna were considered. for this, a biological monitoring network was formed with five wells that present an electrical conductivity gradient (ec) between 82.5 and 1,360 μs/ cm and depths ranging from 3.2 to 5.26 m. from the selected wells, samples were taken in both the dry and wet periods. the samples were taken with two meshes of 180 and 39 μm respec­ tively to obtain organisms. for sampling, the meshes are lowered to the bottom of the well where the sediments are shaken for a period of 20 seconds, after this step the meshes are collected and washed with distilled water, the contents are transferred to la­ belled containers for laboratory identification (malard et al., 2002); hahn & matzke (2005); boulton et al., 2008); & tione et al., 2014). all water samples with possible biological content were preserved with analytical grade alcohol and trans­ ported in iceboxes for laboratory analysis. the biological samples were analyzed by two qualitative procedures, which consist of counting the morphotypes using an optical microscope, in order to obtain the number of individuals per millilitre in the samples, and another quantitative analysis carried out by means of an in­ verted microscope which shows the morphotypes of the samples in order to identify them by taxonomic registration. these two procedures allow the determination of the type and quantity of microorganisms in the samples. 4. results for the groundwater supply, a weighted average recharge of 270.9 mm/year was calculated. this value, distributed between actual recharge surfaces for shallow levels (323.0 km2) and those in which infiltration is possible that later acts as recharge for the deep levels (137.4 km2) allows the estimation of an approximate value of the volume of annual water that would enter the system: 87.5 mm3 to the unconfined aquifer and 37.2 mm3 to the confined aquifer. the current demand for groundwater is 24 mm3/year. the utilization rate for each sector is as follows: households 15.9%, industry 7.9%, agriculture 75.8% and livestock produc­ tion 0.4%. in the study area, the most extensive land use is the permanent crops with 37.01% of the total area, which is linked to the agricultural activity of banana cultivation and a further 31.57% for grazing. the modelling of the average piezometric surface in the rainy season shows that the general tendency of the groundwater flow in the aquifer travels from the serranía de abibe to the chan­ nel of the lion river in the centre and south, and to the gulf of urabá, following a southeast-northwest direction to the north of the study area (figure 3). however, the average piezometric sur­ face for the dry season evidences alterations in the flow direction, presenting in some sections low piezometric heads, because the irrigation wells, used for agricultural activity of the banana, are only pumped during this period. regarding the modelling result both for the steady state and transient, this is considered satisfactory according to the litera­ ture as pearson correlation coefficients were between 77% and 95% in the three modelling scales. during the calibration exer­ cise, it was possible to detect that the model is more sensitive to recharge (the recharge values calibrated in the three periods de­ fined for the year 2011 are presented in table 2) and water level in the rivers, since these generate significant ascents or descents in the aquifer’s piezometric levels. finally, it was possible to iden­ tify following the direction of the east-west flow shown in the pi­ ezometric surface modelled (figure 3) that on a regional scale the equipotentials pseudo-parallel flow to the surface, even in the border neighbourhoods, river and drain. in the intermediate model these equipotentials show a tendency to interact with wet­ lands and rivers, then with the detail of the local model, the bet­ ter defined equipotentials show the relationship between ground­ water and surface waters (figure 4). it is clear that this is an effect of the refinement that can be achieved when there is a better res­ olution with more representative information, which at the same time allows the discretization of the data and more representative geometry of the hydrogeological system. the hydrogeochemistry, in terms of anion composition, shows that the groundwater of the evaluated system has a bicar­ bonate nature, with significant variations in the content of cations. the hydrochemical evolution of ca2+ hco3 ­ and ca2+ mg2+­ hco3 ­ facies, include silicate and carbonate weathering pro­ cesses, as well as ion exchange processes of mg and ca to na (ossa & betancur, 2016). the hydrogeochemical evolution table 2. calibrated recharge. period recharge (mm/day) zone 1 (clays) zone 2 (sands) zone 3 (gravels ) december (2010)-march(2011) 0.3 0.7 1 april-september (2011) 0.3 0.6 0.9 october-november (2011) 0.2 0.5 0.7 g eologia c roatica ossa et al.: physical, chemical and biological characterization as support for water governance in a hydrogeological system of colombia 101 of the groundwater shows regional differences related to various features, among which the following stand out: variability in the stratigraphic characteristics of the system, differences in the de­ grees of connection between permeable layers, changes in the conditions of hydraulic conductivity, variation in the depth of the captured layers of the aquifer, and differences in the distance to the zones of recharge (ossa & betancur, 2018). the greater confinement of the aquifer system is found to­ wards the center and north, with a recharge zone to the east in the foothills of the abibe mountains, showing greater mineralization figure 3. piezometric surface and cross section. g eo lo gi a c ro at ic a geologia croatica 71/2102 to this area. in the southern part of the study zone, the biggest connection between the multilayer aquifer system and meteoric conditions occur through the permeable layers, showing less evolved and mineralized waters towards this zone (ossa & betancur, 2018). in the shallow levels, in addition, there may be affectations to the chemistry of the groundwater by anthropo­ genic contamination from agricultural activities, livestock, poor management of solid waste, and the lack of sewer system. with regard to the levels and composition of the natural chemical background, table 3 summarizes the values for the lower and upper limits of each chemical parameter, considering the percentiles as mentioned above based on the number of sam­ ples belonging to each parameter. in addition, the median is pre­ sented, as a central value which is less sensitive to extremes. these concentrations are presented by differentiating the deep and shallow levels, since the chemical characteristics can vary significantly with depth. an outcome of the biological characterization, (from the ob­ servation of samples analyzed in the laboratory using the methodologies described above), stygofauna were detected in four of the five sampling points. the stygofauna belong to groups of or­ ganisms including: macroinvertebrate larvae, nematodes, vari­ ous metazoans, amoebas, copepods in different stages, ostra­ cods, cladocerans, and different types of algae that may be the result of the interaction between the superficial water and the aquifer (figure 5). table 4 shows the distribution of the organisms in each of the sampling periods (wet season: november or dry season: march). it has been observed that the copepod and nematode morphotypes disappeared in the dry season while a new morphotype appears in the dry season known as cladocerans. regarding the dominance of morphotype by sampling pe­ riods, copepods dominate in the wet season, while ostracods dominate in the dry season. 5. conclusions according to the conceptual hydrogeological model in the urabá region the aquifer has multilayer characteristics, with variations in the permeability of the layers, from the low permeability clayey aquitard layers located predominantly in the north, to the more permeable layers toward the central and southern areas. in addition, the permeable layers occur at times at the surface con­ stituting an unconfined system but in some areas these are sepa­ rated from the surface by thick clayey layers that characterise a confined or semi-confined aquifer. these elements make this sys­ regional scale subregional scale local scale figure 4. flow direction vs scale of modelling. g eologia c roatica ossa et al.: physical, chemical and biological characterization as support for water governance in a hydrogeological system of colombia 103 tem complex, both in the understanding of its physical and chemical characteristics, as well as in relation to its management. comparing demand versus supply, and taking into account the groundwater scarcity indicator in colombia, regulated by resolution 872 (2006) and considering that this multilayer aqui­ fer can obtain contributions from the shallow levels and by dis­ tant flows, it was concluded that the water scarcity index of the hydrogeological system is between medium high and high. the modelling is satisfactory; the pearson correlation coef­ ficients are between 77% and 95% for the three modelling scales, representing magnitudes that are in accordance with those rec­ ommended in the literature. with the multi­scale numerical mode­ lling, it was possible to nest a local model within an intermediate model and these within a regional model, allowing ­ to the extent that resolution and detail were gained ­ to transcend from the characterization of regional flows to the identification of interme­ diate and local flows, in which the interaction between ground­ water and surface water was evidenced, involving not only shal­ low levels of the multilayer aquifer system, but evidencing the occurrence of upward flows. the results of numerical modelling are consistent with the conceptual flow model and reproduce val­ idated trends using hydrogeochemical and isotopic techniques (ossa & betancur, 2018). table 3. natural chemical background levels for the hydrogeological system of the gulf of urabá. parameter deep aquifer (greater than 30 m) shallow aquifer (less than 30 m) lower value upper value median number of samples lower value upper value median number of samples ph 5.45 7.60 6.88 79 5.95 7.13 6.72 52 t (°c) 26.20 28.52 26.90 69 27.10 29.55 28.55 46 ec(µs/cm) 73.00 2455.15 642.50 88 36.55 960.00 411.10 59 tds (mg/l) 56.00 1499.80 423.00 68 20.00 624.80 228.00 59 na+ (mg/l) 0.35 346.64 74.00 89 1.00 82.02 26.20 59 k+ (mg/l) 0.10 12.65 1.92 83 0.10 7.53 2.03 59 mg2+ (mg/l) 0.71 116.21 18.50 89 1.97 33,66 11.41 59 ca2+ (mg/l) 3.67 140.60 33.00 89 7.70 80.94 34.60 59 mn2+ (mg/l) 0.08 1.60 0.83 61 0.04 3.00 0.98 59 nh4 + (mg/l) 0.07 2.94 1.02 24 0.03 0.81 0.28 22 fe3+ (mg/l) 0.02 8.48 1.72 85 0.05 7.02 2.09 58 cl(mg/l) 0.54 489.84 6.26 89 0.74 71.48 16.14 59 so4 2(mg/l) 0.42 36.70 4.57 84 1.50 56.38 18.00 58 hco3 (mg/l) 26.84 975.80 397.72 89 31.00 478.35 150.74 59 co3 (mg/l) 0.00 0.00 0.00 80 0.00 0.00 0.00 18 no3 (mg/l) 0.00 7.75 0.22 89 0.02 6.28 1.46 59 po4 3(mg/l) 0.01 5.29 1.99 33 0.00 1.03 0.15 28 si (mg/l) 6.72 44.88 34.80 22 4.85 13.95 10.44 6 table 4. density of stygofauna organisms occurring in samples. parameter november 2015 march 2016 ostracod density (organisms/ml) 7.464 8.362 copepod density (organisms/ml) 9.875 0 nematodes density (organisms/ml) 8.281 0 cladocerans density (organisms/ml) 0 472 total density organisms/ml) 21.273 8.834 average temperatura (c°) 28.3 28.7 average dissolved oxygen (mg/ml) 4.0 4.4 average electric conductivity (µs/cm) 358.4 524.2 figure 5. morphotypes of detected stygofauna in the hydrogeological system of the gulf of urabá. g eo lo gi a c ro at ic a geologia croatica 71/2104 natural background values are a starting point for the envi­ ronmental authority to issue regulatory standards to identify sub­ sequent changes in quality, recognizing abnormal concentrations beyond these concentration limits of upper values. the upper values in parameters such as electric conductivity, tds, fe, so4 are greater than the values required in colombian regulations, how­ ever, these parameters may be above those resulting from natural conditions such as permeability, stratigraphic conditions, system of flows. it should be borne in mind that these concentration ranges are applicable only to this aquifer, since the other systems may have different geological, chemical, atmospheric conditions, among others, that can considerably alter these ranges. however, the methodology used can be applied to all other systems. it was possible to verify the presence of stygofauna in the shallow levels of the urabá multilayer aquifer. previously and at present, it is not possible to establish a clear correlation between the density of morphotypes with some physicochemical charac­ teristics of the groundwater; therefore, future sampling is pro­ posed in order to obtain more data that allow the creation of a data matrix with enough elements to create a quality indicator. this work opens a new line of interdisciplinary research among hydrogeologists, ecologists and biologists, which is useful for gaining a better understanding of environmental systems and for the integrated adequate management of groundwater as an ecosystem. a significant contribution is that the present study is the first work carried out in colombia with the purpose of identifying the presence of stygofauna in an aquifer system and to seek relation­ ships between the detected species and the quality of the water. finally, all the improvement of hydrogeological knowledge in this colombian aquifer system generates the need to imple­ ment new policies, agreements and instruments that are consis­ tent with these new findings. this, complemented by the cultural and participative knowledge of the social actors who are part of the territory and who have some role in the groundwater, will help to improve the governance of the water resource in the region. acknowledgement this work was possible thanks to the financial aid from cor­ pouraba and colciencias “patrimonio autónomo fondo nacional de financiamiento para la ciencia, la tecnología y la innovación francisco josé de caldas”. references boulton, a.j., fenwick, g.d., hancock, p.j. & harvey, m.s. (2008): bio­ diversity, functional roles and ecosystem services of groundwater invertebrates.– invertebrate systematics, 22/2, 103–116. doi: 10.1071/is07024 corpouraba & universidad de antioquia (2014): actualización del modelo hidrogeológico conceptual del sistema acuífero del urabá antioqueño.– me­ dellín. duque, j., betancur, t., garcia, d., palacio, p., paredes, v. & ville­ gas, p. (2016): modelación de la geometría de un sistema acuífero complejo multicapa. caso de estudio: urabá antioqueño, colombia.– revista latino-americana de hidrogeología, 10/1, 7. edmunds, w.m., shand, p., hart, p. & ward, r.s. (2003): the natural (baseline) quality of groundwater: a uk pilot study.– the science of the total environment, 310/1–3, 25–35. environmental simulations incorporated (2015): groundwater vistas manual, from http://www.groundwatermodels.com/groundwater_vistas.php hahn, h.j. & matzke, d. (2005): a comparison of stygofauna communities inside and outside groundwater bores.– limnologica ecology and management of in­ land waters, 35/2, 31–44. doi: 10.1016/j.limno.2004.09.002 harbaugh, a. & mcdonald, m. (1996): user’s documentation for mod­ flow-96, an update to the u.s. geological survey modular finite-difference ground-water flow model. open-file report, us geological survey, 96–485. hounslow, a. (1995): water quality data: analysis and interpretation, 1st. ed. okla­ homa, usa: crc press, 1995, 397 p. igac & gobernación de antioquia (2007): levantamiento semidetallado de las coberturas terrestres, departamento de antioquia. bogotá. joyce, s., hartley, l., applegate, d., hoek, j. & jackson, p. (2014): mul­ ti-scale groundwater flow modelling during temperate climate conditions for the safety assessment of the proposed high-level nuclear waste repository site at fors­ mark, sweden.– hydrogeology journal, 22, 1233–1249. doi.org/10.1007/s10040014-1165-6. malard, f., dole-olivier, m.j., mathieu, j. & stoch, f. (2002): sampling manual for the assessment of regional groundwater biodiversity. protocols for the assessment and conservation of aquatic life in the subsurface (pascalis) 2001/1, 1–27. ministerio de ambiente y desarrollo sostenible (2014): guía para la formulación de planes de manejo ambiental de acuíferos, bogotá. ministerio de ambiente, vivienda y desarrollo territorial (2006): resolución 872 de 2006, metodología para el cálculo del índice de escasez para aguas subterráneas. bogota d.c. ossa, j. & betancur, t. (2018): hydrogeochemical characterization and identifica­ tion of a system of regional flow. case study: the aquifer on the gulf of urabá, colombia.– revista facultad de ingeniería, 89, 9–18. doi: 10.17533/udea.redin. n86a02 shand, p., edmunds, w.m., lawrence, a.r., smedley, p. & burke, s. (2007): the natural (baseline) quality of groundwater in england and wales, p. 72. tione, m.l. & blarasin, m. (2014): cuaderno de estudios de aguas subterraneas: el acuifero como ecosistema i. (eds.): comunidades de invertebrados en aguas subterráneas y su relación con variables ambientales. argentina, 2014/ 1, 1–21. wwap (united nations world water assessment programme) (2016): the united na­ tions world water development report 2016.– water and jobs, paris, p. 148. 2019 | 72/3 | 195–203 | 12 figs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction sea level is a global boundary with weathering and erosional pro­ cesses prevailing above it, whereas the accumulation of sediments occurs below it. in accordance with sea level changes during geo­ logical history, the intensity and location of erosion and accumu­ lation of sediments also changed (cowell & thom, 1997). remnants of the effects of sea level changes have been found on the coastal and submarine relief in the kvarner area in the north­ eastern part of the adriatic sea (benac & juračić, 1998). this paper analyses the origins of two tombolos (one recent and one submerged) and their conditional dependence on the ho­ locene sea level rise. both tombolos are located on the southwest­ ern coast of prvić island in the kvarner area, in the northeastern part of the adriatic sea (fig. 1a). a tombolo is a depositional geomorphological landform (sandbar, barrier or spit) that joins an island or a barrier with ei­ ther the mainland or another island, resulting from longshore drift or the migration of an offshore bar toward the coast (ward, 2004). although they are a relatively rare geomorphological phe­ nomenon, they have been studied all over the world, eg: finland (schwartz et al., 1989), australia (sanderson & eliot, 1996), japan (kan et al., 1997) and the united kingdom (flinn, 1997; hansom, 2003). there are also a number of tombolos in the mediterranean sea, eg: italy (gosseaume, 1973; aiello et al., 2007), france (vu et al., 2018, 2018b), le­ banon (marriner et al., 2007, 2008) turkey (ceylan, 2012) and egypt (torab, 2016). tombolos length varies from few tens of metres behind small obstacles, up to more than ten kilometers. single tombolos are on the origin of both a recent and submerged tombolo on prvić island in the kvarner area (adriatic sea, croatia) čedomir benac1, neven bočić2 and igor ružić1 1 university of rijeka, faculty of civil engineering, department of hydrotechnics and geotechnics, radmile matejčić 3, 51 000 rijeka, croatia; (cbenac@gradri.uniri.hr; iruzic@uniri.hr) 2 university of zagreb, faculty of science, department of geography, marulićev trg 19/ii, 10 000 zagreb, croatia; (nbocic@geog.pmf.hr) doi: 10.4154/gc.2019.14 abstract this paper analyzes the origins of two tombolos (one recent and another fossil/submerged) on the southwestern coast of prvić island, which is located in the kvarner area in the northeastern part of the adriatic sea. a recent tombolo on cape pipa was formed by the erosion of quaternary deposits and palaeogene siliciclastic rocks. the submerged tombolo is much bigger, clearly visible on the sea bed toward the southwest. the conditions for forming a submerged and recent tombolo have occurred during a slow rise and then stagnation of sea level of the adriatic sea in the holocene. the sea flooded the fossil tombolo probably in the final part of a period of rapid sea-level rise at the beginning of the holocene when a large proportion of the quaternary sediments were eroded. waves from the northwest (tramuntana) and southeast (jugo) refract and diffract around the tombolo. the nourishment of the beach body happens permanently on both sides of the cape. accumulated sediments are protected by resistant rocky blocks of breccia on the peak of cape pipa, acting as a natural tombolo. due to the fact that wave directions are perpendicular to the beach coastline, they do not generate longshore currents that would erode sediment in beach bodies around cape pipa. therefore, the recent tombolo is probably stable in the present climatic and oceanographic conditions in the kvarner area. the most common but there are also tombolo pairs and triplets (gosseaume, 1973; marriner et al., 2008; ceylan, 2012). the preconditions for tombolo formation are: (i) high se­ diment supply, (ii) a physical barrier against the swell and (iii) coastal processes conducive to the development of a sand bank, i.e., bidirectional currents converging towards this physical ba­ rrier (davies, 1980, according to marriner et al., 2008). geomorphological forms like tombolos are rare on the croatian coast of the adriatic sea and have not been studied in the scien­ tific literature so far. this is the first known scientific research of the morphogenesis of recent and submerged tombolos at nearby locations. 2. study area prvić island is elongated in the nw­se direction. the surface of the island is 12.76 km2, maximum length is 7.84 km, maximum width is 2.6 km and the total length of the coast is 23.12 km (duplančić­leder et al., 2004). the highest peak of the is­ land is 356 m above mean sea level (m.s.l), (fig. 1c). this island is mostly formed of carbonate rocks consisting of upper cretaceous limestone and dolomitic limestone, palaeogene foraminiferal limestone, and partially of palaeogene siliciclastic rocks i.e. marls and flysch (mamužić et al., 1969; benac et al., 2013). the bare karstic plateau in the central area of the island has an elevation of > 300 m above m.s.l. (fig. 1b, c). the northeastern slopes between cape stražica (nw) and cape šilo (se) are mostly very steep, with an average inclination > 70°, and many vertical scarps are located above the shore. the carbonate rock mass is partially covered by active talus. subma­ rine slopes are also very steep, resulting in the 50 m isobath being article history: manuscript received september 20, 2018 revised manuscript accepted june 21, 2019 available online october 31, 2019 keywords: tombolo, marine erosion, coastal geomorphology, sea-level rise, holocene g eo lo gi a c ro at ic a geologia croatica 72/3196 figure 1. a-location map; b-simplified geological map (according to mamužić et al., 1969): 1-neogene limestone breccia, 2-palaeogene foraminiferal limestone and flysch, 3-upper cretaceous limestone and dolomitic limestone, 4-reverse fault, 5-anticline axis, 6-proposed fault; c-basic relief characteristics of prvić island. figure 2. the southwestern coast of prvić island (photo: ž. gržančić): 1 – cape pipa, 2 – the njivice rock. g eologia c roatica benac et al.: on the origin of both a recent and submerged tombolo on prvić island in the kvarner area (adriatic sea, croatia) 197 mostly <100 m from the coastline. the slopes are more gently inclined in the western part of the island. a dry karstic valley, the smokova draga is a dominant exogenous geomorphological form (fig. 1c). cape pipa is located in the central part of the southwestern coast of prvić island where the coastal relief and geologic fabric are very different in relation to other coastal parts of this island. steep or vertical upper parts of the slopes are formed of carbo­ nate rocks, and the tectonic fabric is complex and not well known. the contact between these carbonate and siliciclastic rocks in the lower part of the slope is a nw­se trending reverse fault (mamužić et al., 1969), (fig. 1b). large blocks of limestone breccia form cape pipa itself and sandy and gravely beaches have formed along both sides of the cape (fig. 2). the sea bed is at a shallow depth around this cape. approximately 340 metres sse from cape pipa lies the nji­ vi ce rock (fig. 2). it is a small rock with a length of about 50 m striking w­e. its largest width is about 12 m, its height is 4 m and its surface is approximately 500 m2. the njivice rock is also built of carbonate breccia, probably of palaeogene age. the investi­ gated part of prvić island is exposed to waves from both the southeast and the northwest which are relatively low compared to waves in the open sea due to their small fetch (see below). 3. methods three different methods were used in this study. in the prepara­ tory phase, various maps were used to provide information on the geomorphological phenomena of the area: topographic map 1: 25,000, croatian base map (1:5000) and digital orthophoto map1. according to information from the visual interpretations of these maps, we found this specific location and recognized active and submerged tombolos at nearby locations. further, we used orthophoto map as a base for the field investigation. the second method was field investigation. the main pur­ pose of the field work was to collect data on landforms and their relationship with the geological structure of the terrain in the wider area of cape pipa. data were obtained by aerial photogra­ phy from an aircraft, geological and geomorphological mapping, and reconnaissance of the underwater part of the exploration area using scuba diving equipment. for geomorphological mapping, a customized methodology was used according to gams et al. (1985) and pavlopoulos et al. (2009). this methodology is based on the morphogenetic determination of observed geomor­ phological processes, forms and conditions which are related to the morphogenesis of tombolos. the geomorphological mapping involved recognizing, locating and drawing on the map the main forms and processes of the coastal and slope morphogenetic type of relief with the main purpose of determining their spatial rela­ tionships. in order to determine the influence of waves on the forma­ tion of the tombolos, numerical modeling was used. numerical simulation was performed using the simulating waves nearshore (swan) numeric model, which is the third generation model for application in coastal areas, based on euler’s equilibrium equa­ tion of spectral waveform (booij et al., 1999). a jonswap wave spectrum with parameter γ = 3.3 was used. numerical simu­ lation of waves was carried out in the wider area of the grgur channel for waves of northwestern (generated by tramuntana wind) and southeastern directions (generated by jugo). the nu­ merical simulation was done for the 50­year return period and for mean sea level. relevant wind strengths for numerical simulation (southeastern direction: 27.4 m/s, northwestern direction: 22.2 m/s) were taken from the wind climate study of the nearby vinodol channel2. based on the data collected from the maps and field work, geomorphological analysis and synthesis were carried out, focu­ sing on the geological and oceanographic conditions, forms and processes that created the recent features of the relief on cape pipa. 4. results cape pipa is formed by sea erosion of the palaeogene siliciclastic rocks (marls and flysch) which are partially covered with younger cohesive sediments, probably of quaternary age (fig. 3). this 1 https://geoportal.dgu.hr/geoportal, state geodetic administration, zagreb 2 croatian meteorological and hydrological service (2006): wind climate for the area at dubračina mouth in crikvenica. zagreb figure 3. cape pipa (photo: č. benac): a) carbonate rock mass, b) quaternary sediments, c) palaeogene flysch, d) gravely beach, e) collapsed blocks of limestone breccia an obstacle, f) tombolo. g eo lo gi a c ro at ic a geologia croatica 72/3198 quaternary sediment body has a form of an irregular triangle with a base length of around 50 m. the height of this quaternary deposit is 10 to 12 m, and outcrops of flysch bedrock are partially visible on its southeastern side. the stratification of the quater­ nary sediment body is clearly visible and bedding planes have a gentle inclination opposite to the coastal slope. according to pre­ liminary field observations, silty sand prevails in this sediment body. some layers contain angular fragments and blocks that originate from the carbonate rock mass. the coastal cliff is formed on both sides of this sediment body. cape vertex itself is formed on collapsed blocks of talus breccia and provides an obstacle to wave motion (fig. 3). behind this obstacle is the accumulation of beach sediments that connect cape vertex with the coast. cape pipa, according to geomorpho­ logical classification (ward, 2004), can be characterized as a tombolo. grains of gravel with an average diameter between 2 and 6 cm prevail in the beach body. coarse sand and subangular pebble grains are partially visible. a much bigger triangular tom­ bolo form is clearly visible on the sea bed southwest of cape pipa. the edges of this form are built of submerged beach sediments. so, we can consider it as a palaeo­coastline, approximately 300 m long. concave traces of ancient coast are clearly visible on the western side and less noticeable on the southeastern side (fig. 4). this submerged tombolo form was formed behind another ob­ stacle. the njivice rock is built of carbonate breccia, probably figure 4. ortho-photo image of cape pipa and the submerged tombolo (dark spots are meadows of posidonia oceanica) 1-submerged beaches, 2-supposed area of submerged tombolo, 3-location of fig. 5. figure 5. outcrops of subvertical layers (photo: č. benac) (precise location is visible in fig. 4). g eologia c roatica benac et al.: on the origin of both a recent and submerged tombolo on prvić island in the kvarner area (adriatic sea, croatia) 199 of palaeogene age. this submerged tombolo lies at an approxi­ mate depth of 10 metres below the recent sea level. unusual dark parallel lines are clearly visible on the ortho­ photo image where these submerged outcrops look like artifi­ cially built walls (fig. 4). exploration using scuba­diving equip­ ment has revealed that they are outcrops of vertical layers of rocks (fig. 5). at first glance, they seem to be carbonate members of a flysch rock mass (calc­arenite and calc­rudite). figure 6. a geomorphological map of cape pipa and the surrounding area. 1-quaternary sediments, 2-palaeogene flysch mostly covered by slope deposits, 3-carbonate rock mass (upper cretaceous limestone and dolomitic limestone and palaeogene foraminiferal limestone), 4-main ridges, 5-reverse fault, 6-fault escarpment, 7-gully, 8-assumed submerged prolluvium fan, 9-recent shoreline in carbonate rock mass, 10-beaches (coarse sand and gravel), 11-recent cliff, 12-recent tombolo, 13-submerged tombolo, 14-assumed position of the shoreline at the time of submerged tombolo genesis, 15-direction of major waves, 16-position of geological cross-sections (see fig. 7). figure 7. geological cross-sections of the submerged and recent tombolos. 1-recent collapsed blocks of breccia, 2-beach sediments (coarse sand and gravel), 3-quaternary sediments (carbonate blocks, fragments and silty sand), 4-palaeogene (?) limestone breccia, 5-palaeogene flysch, 6-more resistant layers in palaeogene flysch. g eo lo gi a c ro at ic a geologia croatica 72/3200 geomorphological and geological conditions in the sur­ rounding area are shown in figures 6. and 7. the recent coastline in the area around the tombolos was formed in palaeogene silici­ clastic rocks and limestone. a little further away, the coast was formed in cretaceous carbonate rocks. palaeogene (siliciclastic and carbonate) rocks are present only at lower elevations whereas cretaceous carbonate rocks are more distant from the beach, on higher elevations with steep slopes. the inland of the prvić island is predominantly formed of cretaceous carbonate rocks with a few deep gullies. these car­ bonate rocks are karstified, but on the steep slopes intensive line ar erosion is also present. according to the shape of the contours and isobaths on topographic maps, we can hypothesize that sedi­ ment eroded from the gullies formed some prolluvium fans, which are now submerged (fig. 6). geological cross­sections indicate several favourable factors that enabled the development of the investigated tombolos (fig. 7). in addition to the above mention obstacles of different geo­ logical origins, the source of beach accumulation material is im­ portant. these are most likely the quaternary sediment body from cape pipa and probably palaeogene flysch (fig. 6). it is pos­ sible that a source of material for the submerged tombolo was the supposed submerged prolluvium fans, but probably in small pro­ portions. the vertical position of the more resistant layers in fly­ sch rock mass (figs. 5, 7) was also likely to have helped protec­ tion against marine erosion of these sediments. the southeastern and northwestern wind directions generate the highest waves in the grgur channel. figure 8 shows signifi­ cant wave height and wave direction simulations using the swan model (booij et al., 1999), which assumes a uniform wind dis­ tribution. according to model results, wind waves coming from the southeast (hs 50=2.40 m) are higher than ones coming from the northwest (hs 50=2.00 m) in the grgur channel. the recent tombolo and the adjacent coast of prvić island are protected from waves from the southeast direction. waves from southeastern di­ rections break on the rock of njivice, and significant shoaling figure 8. significant wave height (in metres) and the main wave direction of 50 year return period in the grgur channel. figure 9. significant wave heights from southwest wave directions for a 50 year return period (in metres) at cape pipa and the njivice rock. g eologia c roatica benac et al.: on the origin of both a recent and submerged tombolo on prvić island in the kvarner area (adriatic sea, croatia) 201 occurs at the submerged tombolo (figs. 6, 9, 10). wind waves from northwestern directions have higher significant wave heights of the same return period than waves from southeastern directions on cape pipa (fig. 10). the effects of wave diffraction and shoaling are clearly mani­ fested around cape pipa. a majority of the incoming wave’s energy dissipates on cape pipa and the surrounding seabed. be­ hind this cape, there is a shadow zone with low wave energy which provides tombolo stability. 5. discussion geomorphologic forms like a tombolo are rare along the croatian coast of the adriatic sea, due to the prevalence of relative resis­ tant carbonate rocks in which processes of mechanical marine erosion are less well expressed (pikelj & juračić, 2013). the same situation occurs in the kvarner area, where a very slow pro­ cess of bioerosion prevails, while marine erosion is more strongly expressed in the less resistant siliciclastic rocks and quaternary deposits (juračić et al., 2009). the origin of the described de­ posits at cape pipa had not been investigated in detail. according to marjanac (2012) these deposits (fig. 3) can be considered as the remains of the glacial terrace. the question arises as to why recent and submerged tombo­ los were formed in nearby locations? the cause may be three geomorphological factors: (1) a specific geological fabric on the southwestern side of prvić island, (2) favourable oceanographic conditions in the grgur channel and (3) the sea level change dur­ ing the holocene. exogenous slope geomorphological processes are very in­ tense on the southwestern coast of prvić island, especially where active talus formation and rock sliding are visible (fig. 2). the erosion of the quaternary sediment body on cape pipa is perma­ nent. sheet wash and rilling types of erosion caused by surface water are visible and consequently, additional feeding of the beach sediment body is active on both sides of the cape (figs. 3, 6). behind barriers, a complicated mechanism of waves, cur­ rents, sediment transport, and morphology occurs. at cape pipa, wave energy will be reflected dissipated and transmitted by over­ topping, waves also diffract around the tombolo (fig. 10). as a result, they generate longshore currents of opposite directions and support erosion or accumulation of sediment in beach bodies around cape pipa. accumulated sediments are then protected by a resistant block of breccia on the peak of cape pipa, creating a natural tom­ bolo (fig. 11), as wave directions on the windward side are per­ pendicular to the beach coastline, and sediment longshore trans­ port on the tombolo is minimal (fig. 10). wave setup in the lee is a combination of diffraction, transmission and partly refraction. the wave direction and energy behind cape pipa seem favoura­ ble for sediment accumulation and retention due to reduced ero­ sion caused by longshore currents. the recent tombolo is in a state of equilibrium in the present climatic and oceanographic conditions in the kvarner area (pen­ zar et al., 2001). stagnation of sea level occurred in the last 7000 years, after the rapid late pleistocene–holocene rise in the adri­ atic sea (lambeck et al., 2004; surić, 2009; benjamin et al., 2017). erosion of an ancient large sediment body has been intensive during this period. namely, the described quaternary sediment body has features of a cohesive soil. therefore, me­ chanical weathering and erosion are intensive and permanent. this sediment body has lower resistance to destructive wave at­ tack in relation to the carbonate rocks. the coarse­grained sedi­ figure 10. significant wave heights (in metres) from the main wave direction for 50 – year return period at cape pipa. g eo lo gi a c ro at ic a geologia croatica 72/3202 ments found at the bottom of the southeastern part of the grgur chanel near šilo cape (pikelj et al., 2009) probably originated from these deposits. the conditions for forming a submerged tombolo occurred during the global sea level rise in the holocene (lambeck et al., 2004; benjamin et al., 2017). the relatively resistant car­ bonate breccia played an important role in the formation of the tombolo. these large rocky blocks provide an obstacle to waves in the shallow and flattened area. this has created conditions for forming beach sediment bodies between the njivice rock and prvić island. the top of the rock is today visible above the sea surface (fig. 2). the sea flooded the tombolo probably during the last phase of rapid sea level rise at the beginning of the holocene and a great proportion of the quaternary sediments was eroded and the coastal cliff was formed. however, the traces of ancient beaches are clearly visible: better on the western side, and less so on the southeastern side (fig. 4). based on the depth of the submerged tombolo of approxi­ mately 10 m, and according to holocene sea­level rise, it can be assumed that the fossil tombolo was formed approximately 7,000 years ago (fig. 12). local oceanographic conditions may have been responsible for formation of the tombolo, because the winds from southeastern directions (jugo) are more frequent and make higher waves than the winds from northwestern directions (tramuntana), driving the sediment behind the outcrop (figs. 8, 9, 10). sea level rise in the range of 2.0 ± 0.9 ­ 3.4 ± 1.1 mm/yr has been recorded from the beginning of instrumental measurements in the adriatic sea (tsimplis et al., 2009). according to new analyses, predicted sea level rise could be 62 ± 14 cm by the end of the 21st century (orlić & pasarić, 2013). possible indications of accelerated sea level rise include extremely high tides recorded in the mareo­ graph in bakar city: + 117 cm above msl from 1st december 2008, +122 cm above msl from 1st november 2012 and + 127 cm above msl from 29th october 20183. this indicates that the recent tom­ bolo is (under these given conditions) an unstable form and it could therefore be eroded and submerged in the future. these recorded extremely high tides are probably the start of a new sustained trend, which will have a negative impact on tombolo stability. ac­ figure 11. the recent tombolo protected by rocky blocks. figure 12. the position of the recent and submerged tombolos relative to holocene sea level rise (according to lambeck et al., 2004). a and b are cross-sections lines (see figs. 6, 7). 3 according to data provided by andrija mohorovičić geophysical institute, department of geophysics, faculty of science, university of zagreb g eologia c roatica benac et al.: on the origin of both a recent and submerged tombolo on prvić island in the kvarner area (adriatic sea, croatia) 203 cording to the expected sea­level rise and more frequent events of extremely high water levels (acqua alta) in the kvarner area, coastal processes might become more intensive. this could con­ tribute to the acceleration of marine erosion, cliff retreat and ex­ pressive changes of beach bodies including tombolos. 6. conclusions within this research, the existence of two (recent and fossil/sub­ merged) tombolos in neighbouring locations on prvić island in the northern adriatic sea has been reported. there are three geomorphological factors important for the emergence of these tombolos: (1) specific geological fabric, (2) oceanographic conditions and (3) sea level change during the holocene. the atypical appearance of palaeogene flysch, quaternary clastites, and submerged subrecent potential prolluvial fans, all in an area dominated by karstified carbonates, enabled the exis­ tence of obstacles as a prerequisite for the formation of tombolos. in addition, geological specificities have enabled the source of material to feed both (recent and submerged) tombolos. windy waves from the northwest (tramuntana) and southeast (jugo) to­ gether with generated longshore currents are responsible for coastal erosion and accumulation of sediment in the beach bo dies at cape pipa. sea level rise during the holocene allowed the emergence of two tombolos at different heights at different times. regarding the depth of approx. 10 m it is supposed that the fossil tombolo could have been submerged approximately 7,000 years ago. two generations of tombolos co­existing at close proximity is a unique phenomenon in the adriatic sea, and possibly in the mediterranean sea. acknowledgment this work has been supported in part by the university of rijeka under the projects uniri­tehnic­18­97 1232, uniri­tehnic­18­298 6805 and geosekva (hrzz ip­2016­06­1854). references aiello, g., barra, d., de pippo, t., donadio, c. & petrosino, c. (2007): geomorphological evolution of phlegrean volcanic islands near naples, southern italy.– zeitschrift für geomorphologie, 51/2, 165–190. doi: 10.1127/0372­ 8854/2007/0051­0165 benac, č. & juračić, m. (1998): geomorphological indicators of the sea level chang­ es during upper pleistocene (wuerm) and holocene in the kvarner region.– acta geographica croatica, 33, 27–45. benac, č., juračić, m., matičec, d., ružić, i. & pikelj, k. (2013): fluviokarst and classical karst: examples from the dinarics (krk island, northern adriatic, croatia). geomorphology, 184, 64–73. doi: 10.1016/j.geomorph.2012.11.01 benjamin, j., rovere, a., fontana, a., furlani, s., vacchi, m., inglis, r.h., galili, e., antonioli, f., sivan, d., miko, s., mourtzas, n., felja, i., meredith­williams, m., goodman­tchernov, b., ko­ laiti, e., anzidei, m. & gehrels, r. (2017): late quaternary sea­level changes and early human societies in the central and eastern mediterranean basin: an interdisciplinary review.– quaternary international, 449, 29–57. doi. org/10.1016/j.quaint.2017.06.025 booij, n., ris, r.c. & holthuijsen, l.h. (1999): a third­generation wave model for coastal regions, part i: model description and validation.– journal of geophysi­ cal research, 104 (c4), 7649–7666. ceylan, m.a. (2012): general overview of the tombolos on turkey’s coastlines. world applied sciences journal, 16/7, 907–914. cowell, p.j. & thom, b.g. (1997): morphodynamics of coastal evolution.– in: carter, r.w.g. & woodroofe, c.d. (eds.): coastal evolution. cambridge univ. press, cambridge, 33–86. davies, j.l. (1980): geographical variation in coastal development. longman, lon­ don­new york, 212 p. duplančić leder, t., ujević, t. & čala, m. (2004): coastline lengths and areas of islands in the croatian part of the adriatic sea determined from the topographic maps at the scale of 1:25 000.– geoadria, 9/1, 4–32. doi: 10.15291/geoadria.127 flinn, d. (1997): the role of wave diffraction in the formation of st. ninian’s ayre (tombolo) in shetland, scotland.– journal of coastal research, 13, 202–208. doi: 10.2112/jcoastres­d­12­00 gams, i., zeremski, m., marković, m., lisenko, s. & bognar, a. (1985): uputstvo za izradu detaljne geomorfološke karte 1: 100000 [a guide to making a detailed geomorphological map 1: 100000 – in croatian].– komisija za geomorfološko kartiranje sfrj, beograd, 80 p. gosseaume, e. (1973): le tombolo triple d’orbetello (toscane).– bulletin de la so­ ciété languedocienne de géographie, 7, 3–11. hansom, j.d. (2003): st ninian’s tombolo.– in: may, v.j. & hansom, j.d. (eds.): coastal geomorphology of great britain. geological conservation review, 28, 1–5. juračić, m., benac, č., pikelj, k. & ilić, s. (2009): comparison of the vulnera­ bility of limestone (karst) and siliciclastic coasts (example from the kvarner area, ne adriatic, croatia).– geomorphology, 107/1–2, 90–99. doi: 10.1016/j.geo­ morph.2007.05.020 kan, h., hori, n., kawana, t., kaigara, t. & ichikawa, k. (1997): the evo­ lution of a holocene fringing reef and island: reefal environmental sequence and sea level change in tonaki island, the central ryukyus.– atoll research bulletin, 443, 1–20. lambeck, k., antonioli, f., purcell, a. & silenzi, i.s. (2004): sea­level change along the italian coast for the past 10,000 yr.– quaternary science reviews, 24, 1567–1598. doi: 10.1016/j.quascirev.2004.02.009 mamužić, p., milan, a., korolija, b., borović, i. & majcen, ž. (1969): os­ novna geološka karta sfrj 1:100.000, list rab l 33­114 [basic geological map of sfry 1:100.00, rab sheet – in croatian].– institut za geološka istraživanja, zagreb. savezni geološki zavod, beograd. marriner, n., morhange, c. & meulé, s. (2007): holocene morphogenesis of alexander the great’s isthmus at tyre in lebanon.– pnas, 104/22, 9218–9223. doi.org/10.1073/pnas.0611325104 marriner, n., goiran, j.p. & morhange, c. (2008): alexander the great’s tom­ bolos at tyre and alexandria, eastern mediterranean.– geomorphology, 100/(3–4), 377–400. doi: 10.1016/j.geomorph.2008.01.013 marjanac, lj. (2012): pleistocene glacial and periglacial sediments of kvarner, north­ ern dalmatia and southern velebit mts. ­ evidence of dinaric glaciation.– unpubl. phd thesis, faculty of science, university of zagreb, 278 p. orlić, m. & pasarić, z. (2013): semi­empirical versus process­based sea­level pro­ jections for the twenty­first century.– nature climate change, 3, 735–738. doi: 10.1038/nclimate1877 pavlopoulos, k., evelpidou, n. & vassilopoulos, a. (2009): mapping geo­ morphological environments. springer, dordrecht­heidelberg­london­new york, 236 p. doi: 10.1007/978­3­642­01950­0 penzar, b., penzar, i. & orlić, m. (2001): vrijeme i klima hrvatskog jadrana, biblioteka geographia croatica, 16, hrvatski hidrografski institut, split, 258 p. pikelj, k., žigić, v. & juračić, m. (2009): origin and distribution of surface sedi­ ments in the grgur channel, adriatic sea, croatia.– geologia croatica, 62/2, 95–105. doi: 10.4154/gc.2009.08 pikelj, k. & juračić, m. (2013): eastern adriatic coast (eac): geomorphology and coastal vulnerability of a karstic coast.– journal of coastal research, 29/4, 944–957. doi: 10.2112/jcoastres­d­12­00136.1 sanderson, p.g. & eliot, i. (1996): shoreline salients, cuspate forelands and tombolos on the coast of western australia.– journal of coastal research, 12/3, 761–773. schwartz, m.l., grano, o. & pyokari, m. (1989): spits and tombolos in the southwest archipelago of finland.– journal of coastal research, 5, 443–451. surić, m. (2009): reconstructing sea­level changes on the eastern adriatic sea (croa­ tia) – an overview.– geoadria, 14/2, 181–199. doi: 10.15291/geoadria.550 tsimplis, m.n., raicich, f., fenoglio­marc, l., shaw, a.g.p., marcos, m., somot, s. & bergamasco, a. (2009): recent developments in under­ standing sea level rise at the adriatic coasts.– physics and chemistry of the earth. parts a/b/c, 59–71. doi: 10.1016/j.pce.2009.11.007 torab, m. (2016): geomorphological & geoarchaeological indicators of the holocene sea­level changes on ras el hekma area, nw coast of egypt.– journal of afri­ can earth sciences, 114, 85–95. doi: 10.1016/j.jafrearsci.2015.11.001 vu, m.t., lacroix, y. & nguyen, v.t. (2018a): investigating the effects of sea­level rise on morphodynamics in the western giens tombolo, france.– iop conference series: earth and environmental science (ees), 167, 1–8. doi: 10.1088/1755­ 1315/167/1/012027 vu, m.t., lacroix, y. & nguyen, v.t. (2018b): empirical equilibrium beach pro­ files along the eastern tombolo of giens.– journal of marine science and appli­ cation, 17/2, 241–253. doi: 10.1007/s11804­018­0027­3 ward, s. (2004): tombolo.– in: goudie, a.s. (ed.): encyclopedia of geomorphology. rutledge, iag, london­new york, 1054 p. geologia croaticageologia croatica ab stra ct this study represents a detailed micropalaeontological investigation of the composition and diversity of planktonic foraminiferal assemblages from the upper turonian to maastrichtian interval of two deep exploration wells (al mahr-1 and palmyra-1) in the palmyride area of syria. in combination with lithostratigraphic analysis, this detailed biostratigraphic study provided important new palaeoecological and palaeoclimatic interpretations and insights into the nature of deposition along the northern passive margin of gondwana during the late cretaceous. the investigated strata belong to three lithostratigraphic units (from base to top): the upper part of the judea formation (upper turonian–lowermost santonian), the soukhne formation (santonian–lower campanian), and the shiranish formation (upper campanian–maastrichtian). the results represent the fi rst detailed determination of planktonic foraminifera from the palmyride region. the presence of rich and diverse foraminiferal associations enabled the establishment of the following nine late turonian to maastrichtian biostratigraphic zones, based on documented indextaxa and/or the entire microfossil assemblages: i) biozone i; ii) biozone ii; iii) biozone iii; iv) contusotruncana plummerae zone; v) biozone v; vi) globotruncanella havanensis zone; vii) pseudoguembelina palpebra zone; viii) racemiguembelina fructicosa zone; and ix) abathomphalus mayaroensis zone. the late turonian to early campanian foraminiferal assemblages (biozones i–iv) are dominated by opportunistic taxa (r-strategists) and suggest a generally fl uctuating subtropical climate and deposition an outer shelf environments. the well­preserved and highly diversifi ed late campanian to maastrichtian foraminiferal assemblages (biozones v–ix) imply the presence of a well­stratifi ed water column, tropical to subtropical climate, and deposition in outer shelf to upper bathyal envi­ ronments. a decrease in the number of globotruncanid species during the late maastrichtian indicates a less stratifi ed water column and unfavourable environmental conditions for k-strategists. the common occurrence of phosphate grains in the soukhne formation (santonian–lower campanian) represents an important indicator of specifi c geological and palaeoenvironmental conditions, such as oxygen defi ciency, up­ welling and transgression. these conditions support the interpretation of the domination by opportunistic planktonic foraminiferal taxa (heterohelicids and muricohedbergellids) in biozone ii. keywords: planktonic foraminifera, biostratigraphy, phosphatic grains, upper turonian–maastrichtian, palmyride region, syria planktonic foraminiferal biostratigraphy and paleoecology of upper cretaceous deposits from the palmyride region, syria  gabrijela pecimotika1, blanka cvetko tešović2 and vlasta premec fućek1 1 e&p research laboratory department, field engineering and operations sector, ina-industrija nafte d.d., exploration and production bd, lovinčićeva bb, 10 002 zagreb, croatia; (gabrijela.pecimotika@ina.hr; vlasta.premec­fucek@ina.hr) 2 department of geology, faculty of science, university of zagreb, horvatovac 102a, 10 000 zagreb, croatia; (bcvetko@geol.pmf.hr) doi: 10.4154/gc.2014.07 geologia croatica 67/2 87–110 10 figs. zagreb 2014 1. introduction the palmyride area is part of the northern arabian platform (fig. 1). the arabian platform was located on the northern passive margin of gondwana bordering the tethys ocean for most of the phanerozoic. the palmyride fold belt was established at the site of an inverted mesozoic rift basin and geologia croatica 67/2geologia croatica 88 developed as a linear trough genetically related to the levantine margin rift system, which formed along a gondwana proterozoic suture zone (brew, 2001). ongoing extension produced a 6 km thick and 200 km laterally extensive palaeozioc and mesozoic sedimentary succession (brew, 2001). tectonic evolution of the area has been strongly influenced by geological activity along the arabian plate boun­ daries: the dead sea transform fault to the west, the bitlis suture and east anatolian fault to the north, and the zagros suture to the east (fig. 1). this study focuses on the upper cretaceous (upper turonian–maastrichtian) succession from two deep exploration wells al mahr-1 and palmyra-1, and was aimed at age determination and correlation (lithoand biostratigraphic) of strata based on their microfossil assemblages (mainly planktonic and some benthic foraminifera). planktonic foraminifera have been abundant in most oceanic environments since their appearance in the middle jurassic and are the most commonly used microfossil group for biostratigraphic zonation and reconstruction of past sea surface-water conditions and palaeoclimate (hemleben et al., 1989; murray, 1991). many studies have focused on biostratigraphic evolution of cretaceous planktonic foraminifera (e.g., robaszynski et al., 1984; 2000; caron, 1985; sliter, 1989; robaszynski & caron, 1995; petrizzo, 2003; pre­ mo li silva & verga, 2004; sari, 2006, 2009; baba zadeh et al., 2007; huber et al., 2008; petrizzo et al., 2011; gardin et al., 2012). previous biostratigraphic investigations of the upper cretaceous deposits in the palmy ride area were undertaken on material from deep exploration wells by lučić (2001), stanković et al. (2003; 2005), and dacer et al. (2007), but not in a great detail. the main purpose of this paper is to establish planktonic foraminiferal zonation of the upper turonian–maastrichtian succession of the palmyride area based on the microfossil assemblages and/or index taxa present in order to improve palaeoenvironmental interpretations of deposition in the palmyride basin during the late cretaceous. the biostratigraphic zonation is compared with the regional tethyan zofigure 1: map showing major tectonic zones in syria and the surrounding areas (modified from litak et al., 1998) and the study area in the palmyride region. a circle represents the approximate location of the hayan block with the al mahr-1 (1) and palmyra-1 (2) exploration wells; distance between the wells is about 50 km. pecimotika et al.: planktonic foraminiferal biostratigraphy and paleoecology of upper cretaceous deposits from the palmyride region, syria geologia croatica 89 nation. documenting variations in planktonic foraminiferal assemblages and any associated lithological changes are critical for making palaeoclimatic and palaeoceanographic interpretations. santonian to early campanian sediments rich in phosphate grains are examined here as an important indicator of specific geological and palaeoenvironmental conditions. the data obtained are compared to those from other coeval regional successions in order to establish the significance of the palmyride strata, as part of the arabian platform, for better understanding of the sedimentary evolution of the broader tethyan region and its response to global environmental changes. 2. geological setting regionally the investigated area is also known as the hayan exploration block (fig. 1), which is located in the palmyride area, an intracontinental transpressive mountain range (lučić, 2001). the palmyrides represent the most distinct tectonic and structural unit in central syria as a zone of subdued topography that extends from the dead sea fault zone to the west, and disappears to the east at the euphrates graben or depression (fig. 1). the palmyrides are 400 km long and 100 km wide, stretching southwest–northeast across syria with a maximum altitude of around 1300 m (lučić & foršek, 2000; brew, 2001; brew et al., 2001; hernitz kučenjak et al., 2006; wood, 2011). in the palmyride area, mesozoic deposits of early triassic to late cretaceous age were observed in all deep wells (lučić et al., 2002). unlike the upper triassic and jurassic deposits (maximum 700 m thick), which can either exhibit substantially reduced thickness (to 200 m minimum) or be absent in some places due to erosion or non-deposition, the cretaceous strata are present throughout the region (approx. 800 m thick). the oldest deposits exposed on the surface are upper triassic evaporites interbedded with shales. jurassic deposits are represented by different varieties of carbonate rocks, and lower cretaceous deposits consist of dolomites and limestones with rare interbeds of anhydrite and shale. in the late cretaceous there was a deepening of the depositional system, which resulted in the deposition of shales and marly limestones with a gradual increase in the amount of marl up­section (ponikarov, 1966a, b; lučić et al., 200. for the purpose of the syrian petroleum company (spc), the investigated upper cretaceous succession is subdivided into three lithostratigraphic units (figs. 2, 3): 1) the upper part of the judea formation (upper turonian–lowermost santonian); 2) the soukhne formation (santonian– lower campanian); and 3) the shiranish formation (upper campanian–maastrichtian); (mouty & al-maleh, 1983). the judea formation is represented by limestones and dolomitic limestones with thin intercalations of yellow to brownish yellow marl. the soukhne formation is characterized by calcareous horizons in the lower part, and by clayey limestones, marls and phosphatic deposits in the upper part. argillaceous limestones, marls, chert and ovoid calcareous concretions (10–30 cm in diameter) are present in the shiranish formation. 3. material and methods the foraminiferal study is based on analyses of 81 samples of upper cretaceous deposits obtained as drill cuttings from two deep exploration wells (al mahr-1 and palmyra-1) drilled in the hayan exploration block in the palmyride area. samples of drill cuttings from mud samples were collected every 5–10 metres. most of the analyzed samples contain very well preserved planktonic and benthic foraminifera. samples for micropalaeontological analyses were disaggregated in tap water and diluted with hydrogen peroxide, then washed through 63 mm, 125 mm, and 160 mm sieves, dried and examined on an olympus szx16 stereomicroscope. representative aliquots of approximately 300 planktonic foraminiferal specimens were counted for quantitative planktonic foraminiferal analyses. the term “„dominant” was used for species that constitute more than 10% of the planktonic foraminiferal assemblage, whereas the terms “„common”, “„fewand “„rare” refer to species comprising 3–10%, 1–3%, and <1% of the assemblage, respectively. plankton/benthic ratios were determined for each biozone on at least 300 specimens from the entire foraminiferal assemblages in >63 mm grain fraction and were used for palaeoecologic and palaeoenvironmental interpretations. petrographic thin­sections were made of 35 samples throughout the upper cretaceous interval for the purpose of lithological interpretation. prepared petrographic thin-sections were stained with alizarin red – s after the method of evamy & shearman (1962) in order to distinguish carbonate minerals. a detailed study of foraminiferal morphology was performed on a scanning electron microscope (sem). the overall preservation of foraminifera is good although their original calcite shells have been recrystallized. the micropalaeontological investigation was focused on the vertical distribution, diversity and composition of mainly planktonic and less abundant benthic foraminiferal assemblages (figs. 2–3) according to gawor­biedowa (1984), loeblich & tappan (1988), ismail (1992), bolli et al. (1994), ly & kuhnt (1994), kaiho (1998), premoli silva &verga (2004), ismail et al. (2007), hampton et al. (2007), and gasiński & uchman (2009). the presence of rich and diverse foraminiferal associations enabled biostratigraphic zonation of the upper turonian to maastrichtian deposits based on documented index-taxa and/or the entire microfossil assemblages. standard planktonic foraminiferal zonation after robaszynski et al. (1984), caron (1985), robaszynski & caron (1995), pre­ moli silva & sliter (1994), robaszynski et al. (2000), premoli silva &verga (2004), sari (2006, 2009), huber et al. (2008), ogg et al. (2008), petrizzo et al. (2011) and pérez­rodríguez et al. (2012) have been used. a zonal sheme which emphasizes the lowest (lo) and the highest occurrences (ho) of index taxa and/or selected species in microfossil associations has been applied. phosphatic grains of the soukhne formation deposits were also analyzed using sem back-scattered electron imaging (bse) and energy dispersive x-ray analysis (edx). the semi-quantitative x-ray elemental mapping of p, f, cl geologia croatica 67/2geologia croatica 90 figure 2: stratigraphic column of the al mahr-1 exploration well showing stratigraphic distribution of planktonic foraminifera (formation names after spc – syrian petroleum company). biozones i (late turonian–early santonian) ii (middle–late santonian) iii (early campanian) iv globotruncana plummerae zone (early–middle campanian) v (late campanian) vi globotruncanella havanensis zone (late campanian) vii pseudoguembellina palpebra zone (late campanian) viii racemiguembelina fructicosa zone (late campanian–early maastrichtian) ix abathomphalus mayaroensis zone (late maastrichtian) pecimotika et al.: planktonic foraminiferal biostratigraphy and paleoecology of upper cretaceous deposits from the palmyride region, syria geologia croatica 91 figure 3: stratigraphic column of the palmyra-1 exploration well showing stratigraphic distribution of planktonic foraminifera (formation names after spc – syrian petroleum company). biozones i (late turonian–early santonian) ii (middle–late santonian) iii (early campanian) iv globotruncana plummerae zone (early–middle campanian) v (late campanian) vi globotruncanella havanensis zone (late campanian) vii pseudoguembellina palpebra zone (late campanian) viii racemiguembelina fructicosa zone (late campanian–early maastrichtian) ix abathomphalus mayaroensis zone (late maastrichtian) geologia croatica 67/2geologia croatica 92 figure 4: correlation between the two exploration wells (al mahr-1, palmyra-1) showing planktonic biozones and lithology. pecimotika et al.: planktonic foraminiferal biostratigraphy and paleoecology of upper cretaceous deposits from the palmyride region, syria geologia croatica 93 and ca was performed using a fei quanta 450 sem with edax team eds at smith college (northampton, massachusetts, usa). 4. biostratigraphy biostratigraphic subdivision of the investigated upper cretaceous successions is based on planktonic foraminifera. stratigraphic ranges of the identified microfossil assemblages indicate a late turonian to maastrichtian age. stratigraphic relationships between the identified planktonic foraminiferal species are shown in figs. 2 and 3, whereas the lithostratigraphic and biostratigraphic biozonation correlation between al mahr­1 and palmyra­1 are presented in fig. 4. the upper turonian to lowermost santonian deposits contain planktonic and benthic foraminiferal assemblages characteristic of this stratigraphic range. these poorly diversified microfossil assemblages have equal proportions of small benthic and planktonic foraminifera. the santonian to lower campanian strata, on the other hand, are characterized by a moderately diversified microfossil assemblage with increased abundance and diversity of planktonic foraminifera, and the absence of nominal taxon/zonal markers. high diversity microfossil assemblages with a dominance of planktonic foraminifera and well-preserved index taxa are present in the upper campanian to upper maastrichtian deposits. previous studies of late cretaceous planktonic foraminifera from the palmyrides only generally indicated the age of the deposits (stanković et al., 2003, 2005; dacer et al., 2007). biostratigraphy of the upper turonian to maastrichtian successions from the al mahr-1 and palmyra-1 wells is correlated with the existing and well-established planktonic foraminiferal zonation for the tethyan realm (robaszynski & caron, 1995; robaszynski et al., 2000; premoli silva & verga, 2004), fig. 5. since the zonal markers are very rare or absent, alternative planktonic foraminiferal species as well as the whole planktonic fora miniferal association enable application of standard biozonation (robaszynski et al., 1984; caron, 1985; sliter, 1989; premoli silva & sliter, 1994; robaszynski & caron, 1995; robaszynski et al., 2000; pre­ moli silva & verga, 2004; chacon et al., 2004; huber et al., 2008; sari, 2009; petrizzo et al., 2011; pe rez­rodríguez et al., 2012). nine biozones have been identified in the upper turonian to maastrichtian succession: biozone i, biozone ii, biozone iii, iv contusotruncana plummerae zone, biozone v, vi globotruncanella havanensis zone, vii pseudoguembelina palpebra zone, viii raceemiguembelina fructicosa zone, and ix abathomphalus mayorensis zone. a list of taxa together with author names and year of publication are provided in the appendix. all of the diagnostic species and some additional taxa typical of the studied foraminiferal assemblages are illustrated in figs. 6–9. biozone i (figs. 6a–d) age. late turonian–early santonian interval. al mahr­1 (185–210 m, figs. 2 and 4), pal­ myra­1 (180–200 m, figs. 3, 4) assemblage characteristics. as index taxa were not observed, the lowest occurrence (lo) of contusotruncana fornicata and globigerinelloides bollii has been used to define the lower boundary of this zone. this biozone may correspond to the dicarinella concavata zone (premoli silva & sliter, 1994; robaszynski & caron, 1995; robaszynski et al., 2000; premoli silva & verga, 2004; sari, 2006, 2009). the foraminiferal assemblage of this interval is composed of rare non-keeled planktonic foraminifera with a wide stratigraphic range: archaeoglobigerina blowi, a. cretacea (figs. 6c, d), whiteinella balthica, whiteinella sp., dicarinella sp. (fig. 6a) and marginotruncana sp. (fig. 6b). in the middle of the biozone muricohedbergella holmdelensis and pseudotextularia nuttalli have their lowest occurrence. the most abundant species in the assemblage are heterohelix reussi, h. moremani, and h. globulosa, comprising 38% of the total planktonic association. biozone i is also characterized by very common pseudotextularia nuttalli, muricohedbergella holmdelensis, muricohedbergella flandrini, marginotruncanids and whiteinellids. in addition, the following small calcareous benthic foraminifera are present and account for up to 50% of the total foraminiferal association: bulimina ovulum, gyroidinoides globosus, bulimina sp., gavellinela sp. (figs. 9a, b), lenticulina sp., and nodosaria sp. lithology and palaeoenvironment. brownish grey to grey limestone (mudstone/wackestone to foraminiferal wacke stone), dolomitic limestone and marl with equal proportions of planktonic and calcareous benthic foraminifera indicate accumulation within outer shelf environments. biozone ii (figs. 6e–i) age. middle–late santonian interval. al mahr­1 (150–185 m, figs. 2 and 4), pal­ myra­1 (140–180 m, figs. 3, 4) assemblage characteristics. because of the absence of a zonal marker, the lower boundary of this zone is defined approximately by the lo of globotruncana linneiana, whereas the upper boundary coincides with the disappearance of all dicarinellids and whiteinellids. this biozone may correspond to the dicarinella asymetrica zone (premoli silva & sliter, 1994; robaszynski & caron, 1995; robaszynski et al., 2000; premoli silva & verga, 2004; sari, 2006, 29). the first half of biozone ii is characterized by the lo of several new taxa such as globotruncana bulloides, g. hilli, g. arca, hendersonites carinatus, heterohelix striata, h. punctulata, h. planata, globigerinelloides prairiehillensis and g. subcarinatus. dominant species in this zone are heterohelix globulosa and h. reussi (fig. 6i), while pseudotextularia nuttalli and heterohelix punctulata are very common. the following planktonic foraminifera continue from the underlying zone: archaeoglobigerina blowi (figs. 6e, f), a. cretacea, contusotruncana fornicata (figs. 6g, h), globigerinelloides bollii, muricohedbergella holmdelensis and marginotruncana sp. globotruncana arca, g. bulloides, and g. linneiana range throughout biozone ii but are geologia croatica 67/2geologia croatica 94 figure 5: proposed biozonation for the upper cretaceous succession and stratigraphic range of selected species of the palmyride region compared with the zonal schemes for tethys (robaszynski and caron, 1995; premoli silva & verga, 2004). timescale was adapted from ogg et al. (2008), and sealevel curve is from haq et al. (1987). grey area indycates the presence of phosphate grains. phate grains and foraminiferal assemblage of biozone ii indicate open marine, most probably outer shelf depositional environments. biozone iii (figs. 6j–n) age. early campanian interval. al mahr­1 (120–150 m, figs. 2 and 4), palmyra­1 (115–140 m, figs. 3, 4) assemblage characteristics. the main characteristic of the microfossil assemblage is the disappearance of marginotruncanids at the base of this biozone while pseudoguembelina costulata has its lowest occurrence. rugoglobigerina rugosa first occurs in the middle part of biozone iii, whereas heterohelix reussi has its highest occurrence (ho). this binot present in every sample. in the upper part of this biozone globotruncanita stuartiformis appears for the first time, while heterohelix moremani and muricohedbergella flandrini have their highest occurrence. the genus heterohelix is very abundant and diverse (6 species), and comprises a very high percentage (46%) of the planktonic association. among calcareous benthic foraminifera, common taxa with a wide stratigraphic range include: bulimina ovulum (fig. 9d), praebulimina reussi, p. kickapoensis, gyroidinoides globosus, bulimina sp., and lenticulina sp. small benthic foraminifera make up to 40% of the microfossil assemblage. lithology and palaeoenvironment. foraminiferal mudstone/wackestone, marl, dolomitic limestones with phospecimotika et al.: planktonic foraminiferal biostratigraphy and paleoecology of upper cretaceous deposits from the palmyride region, syria geologia croatica 95 figure 6: sem photomicrographs of selected planktonic foraminifera observed in biozone i (a–d), biozone ii (e–i), biozone iii, (j–n) and contusotruncana plummerae zone (biozone iv, o, p). a dicarinella sp., palmyra-1, interval 190–200 m. b marginotruncana sp., al mahr-1, interval 190–200 m. c, d archaeoglobigerina cretace (c), and detail of the wall texture (d), al mahr-1, interval 185–190 m. e, f archaeoglobigerina blowi (e), and detail of the wall texture (f), palmyra-1, interval 160–170 m. g, h contusotruncana fornicata, al mahr-1, interval 155–160 m. i heterohelix reussi, palmyra-1, interval 140–150 m. j heterohelix globulosa, palmyra-1, interval 130–140 m. k, l muricohedbergella holmdelensis, palmyra-1, interval 120–130 m. m, n heterohelix striata (m), and detail of the wall texture (n), al mahr-1, interval 120–130 m. o, p contusotruncana plummerae, palmyra-1, interval 100–110 m. geologia croatica 67/2geologia croatica 96 ozone may correspond to the globotruncanita elevata zone (caron, 1985; sliter, 1989; premoli silva & sli­ ter, 1994; robaszynski & caron, 1995; roba­ szyn ski et al., 2000; premoli silva & verga, 2004; chacon et al., 2004). dominant species in the planktonic foraminiferal assemblage are hendersonites carinatus, heterohelix striata, h. punctulata and pseudotextularia nuttalli, while globigerinelloides bollii is very common. in addition, the microfossil assemblage contains the following planktonic foraminifera that continue from biozone ii: archaeoglobigerina cre taca, a. blowi contusotruncana fornicata, globotruncana linnei ana, g. bulloides, g. hilli, g. arca, globotruncanita stu ar ti formis, heterohelix globulosa (fig. 6j), h. planata, globi gerinelloides prairiehillensis, g. subcarinatus, muricohedbergella holmdelensis, and muricohedbergella sp. spe cimens of the genus heterohelix remain diverse and constitute the most abundant group in the microfossil association with 47% of the planktonic foraminiferal assemblage. most of the calcareous benthic foraminifera that persisted from the underlying biozone ii, and comprise up to 35% of the microfossil assemblage, include bulimina ovulum, buli mina sp. (fig. 9e), gyroidinoides globosus, lenticulina rotulata, lenticulina sp., and oridosalis sp. lithology and palaeoenvironment. argillaceous limestone (mudstone/wackestone) and marl together with microfossils of biozone iii suggest an open marine, most probably outer shelf depositional environment. biozone iv: contusotruncana plummerae zone (figs. 6o, p, 7a, b) definition. stratigraphic interval from the lo of contusotruncana plummerae to the lo of radotruncana calcarata (petrizzo et al., 2011) age. early to middle campanian interval. al mahr­1 (85–120 m, figs. 2 and 4), palmyra­1 (80–115 m, figs. 3, 4) assemblage characteristics. beside the lo of the zonal marker contusotruncana plummerae (figs. 6o, p) the lower boundary of this biozone is also characterized by the lo of hendersonites carinatus and by the first occurrence of laeviheterohelix glabrans, muricohedbergella mounmouthensis and heterohelix navarroensis. the planktonic foraminiferal assemblage is similar to that in biozone iii. however, planktonic foraminifera are more abundant and the overall number of species increased. the dominant species include heterohelix striata, h. planata, pseudoguembelina costulata and pseudotextularia nuttalli. in addition, the assemblage is characterized by common muricohedbergella holmdelensis, m. monmouthensis, globigerinelloides bollii (fig. 7a), g. subcarinatus and heterohelix globulosa. other species in this zone include: archa eoglobigerina blowi (fig. 7b), a. cretacea, contu so truncana fornicata, globotruncana arca, g. bulloides, g. linneiana, g. hilli, globotruncanita stuartiformis, heterohelix punctulata, globigerinelloides prairiehillensis, muricohedbergella sp. and rugoglobigerina rugosa. representatives of the genus heterohelix decrease in abundance to 32%, whereas pseudoguembelinids increase in diversity as well as in abundance and can account for up to 10.5% of the total assemblage. the amount of calcareous benthic foraminifera decreases to 30% of the assemblage. the most common taxa include bulimina ovulum, gavelinella monterelensis (fig. 9c), gyroidinoides globosus, lenticulina rotulata, lenticulina sp. (fig. 9f), gavelinella sp., gyroidinoides sp., and cibicidoides sp. lithology and palaeoenvironment. argillaceous limestone (wackestone), marl, as well as calcareous marl with abundant planktonic foraminifera (70%) indicate outer shelf to upper bathyal depositional environments. biozone v (figs. 7c–g) age. late campanian interval. al mahr­1 (80–85 m, figs. 2 and 4), palmyra­1 (75–80 m, figs. 3, 4) assemblage characteristics. since the zonal marker is very rare and generally poorly preserved, the base of biozone v is marked by the lo of laeviheterohelix dentata, globotruncanella havanensis and globotruncanita stuarti. this biozone may correspond to the radotruncana calcarata zone (robaszynski & caron, 1995; premoli sil va & sliter, 1994; robaszynski et al., 2000; pre moli silva & verga, 2004; sari, 2006, 2009; huber et al., 2008). the species heterohelix labellosa appears in the middle part of biozone v. the planktonic foraminiferal assemblage of this biozone is abundant and highly diversified. most planktonic foraminifera persist from the underlying biozone iv, including archaeoglobigerina blowi, a. cretacea, contuso trunca na fornicata, globotruncana arca (figs. 7e, f), g. bulloides, g. linneinana, g. hilli, heterohelix globulosa, h. navarroensis, h. planata, h. punctulata, h. striata, globigerinelloides bollii, g. prairiehillensis (fig. 7g), g. subcarina tus, laeviheterohelix glabrans, muricohedbergella holm delensis, m. mounmouthensis, muricohedbergella sp., pseudo guem belina costu lata, pseudotextularia nuttalli (fig. 7c), and rugoglobigerina rugosa (fig. 7d). the genus heterohelix constitutes 38% of the assemblage and remains the most abun dant group in the planktonic association. in comparison with previous biozones, the diversity of biozone v increases and the total number of planktonic foraminifera reaches 27 species. small benthic foraminifera comprise less than 20% of the assemblage and include bolivina incrassatea, gavelinella monterelensis, gavelinella sp., gyroidinoides globosus, lenticulina rotulata, lenticulina sp., neoflabelina reticulata, serovaina complanata, and cibicidoides sp. lithology and palaeoenvironment. argillaceous limestone and calcareous marl with abundant planktonic foraminifera (80%) indicate outer shelf to upper bathyal depositional environments. biozone vi: globotruncanella havanensis zone (figs. 7h–j) definition. partial range zone from the lo of globotrunca nella havanensis to the lo of pseudoguembelina palpebra (huber et al., 2008) pecimotika et al.: planktonic foraminiferal biostratigraphy and paleoecology of upper cretaceous deposits from the palmyride region, syria geologia croatica 97 age. late campanian interval. al mahr­1 (70–80 m, figs. 2 and 4), palmyra­1 (65–75 m, figs. 3,4) assemblage characteristics. the zonal marker globotruncanella havanensis (fig. 7h) is relatively rare, while species pseudoguembelina excolata, planoglobulina carseyae and rugoglobigerina hexacamerata have their lowest occurrence at the base of the biozone iv. the following planktonic foraminifera continue from the underlying biozone v: archaeoglobigerina blowi, a. cretacea, contusotruncana fornicata, globotruncana arca, g. buloides, g. linneinana, g. hilli, globotruncanita stuartiformis, g. stuarti, heterohelix globulosa, h. navarroensis (figs. 7i, j), h. planata, h. punctulata, h. striata, globigerinelloides bollii, g. prairiehillensis, g. subcarinatus, laeviheterohelix glabrans, l. dentata, muricohedbergella holmdelensis, m. mounmouthensis, muricohedbergella sp., pse udo guembelina costulata, pseudotextularia nuttalli, and rugoglobigerina rugosa. in the middle of the biozone globotruncanella petaloidea, rugoglobigerina macrocephala and guembelitria turrita have their lo. species of genus heterohelix remain the most abundant group in the microfossil assemblage with 37.5% representation. globotruncanids increase in diversity (8 species) and abundance (13.5%), and become an important component of the planktonic assemblage. in addition, small benthic foraminifera comprise 15% of the total fauna and include bolivina incrassata, gaveli nella monterelensis, gavelinella sp., gyroidinoides globosus, lenticulina rotulata, lenticulina sp., neoflabelina reticulata, serovaina complanata, cibicidoides sp. (fig. 9h), and an agglutinated form spiroplectamina sp. (fig. 9g). lithology and palaeoenvironment. marl and argillaceous limestone (mudstone/wackestone) with abundant planktonic foraminifera (85%) suggest outer shelf to upper bathyal depositional environments. biozone vii: pseudoguembelina palpebra zone (figs. 7k–p, 8a) definition. partial range zone from the lo of pseudoguembelina palpebra to the lo of racemiguembelina fructicosa (huber et al., 2008) age. late campanian–early maastrichtian interval. al mahr­1 (35–70 m, figs. 2 and 4), palmyra­1 (30–65 m, figs. 3, 4) assemblage characteristics. pseudoguembelina palpebra (fig. 7n) is consistently present in this biozone. the first occurrence of globotruncanella pschadae, pseudoguembelina kempensis and racemiguembelina powelli is recorded in the lower part of this biozone. gansserina gansseri (figs. 7o, p) is present, but very rare, throughout this interval.very common species in the assemblage include heterohelix globulosa, pseudoguembelina costulata (fig. 7m), heterohelix striata, and h. navarroensis. common species include heterohelix labellosa, pseudoguembelina excolata, pseudotextularia nuttalli, and rugoglobigerina rugosa (figs. 7l, 8a). other representative species are archaeoglobigerina blowi, a. cretacea, contusotruncana fornicata, globotruncana arca,g. bulloides, g. linneiana, g. hili, globotruncanella havanensis, g. petaloidea, globotruncanita stuarti, g. stuartiformis, guembelitria turrita, g. cretacea, heterohelix planata, h. punctulata, globigerinelloides bollii, g. prairiehillensis, g. subcarinatus, laeviheterohelix dentata, l. glabrans, muricohedbergella holmdelensis, m. mounmothensis, muricohedbergella sp., planoglobulina carseyae, rugoglobigerina hexacamerata (fig. 7k), and r. macrocepha la. the middle part of biozone vii is characterized by the lowest occurrence of abathomphalus intermedius, globotruncanella minuta and globotruncanita pettersi, while globigerinelloides bollii become extinct. the upper part of this biozone is also characterized by the lowest occurrences of pseudotextularia intermedia and globotruncanita conica. in comparison with biozone vi, biodiversity significantly increases throughout biozone vii and reaches the maximum of 41 species. this increase is partly related to speciation of globotruncanids, (represented by 12 species). the genus heterohelix remains the dominant group with 34% abundance, whereas pseudoguembelinids remarkably increase up to 17%. globotruncanids, despite numerous species, represent 15% of the planktonic foraminiferal population. among calcareous benthic foraminifera the most common taxa are: bolivina incrassata, bolivinoides miliaris, gavelinella monterelensis, gavelinella sp., gyroidinoides globosus, lenticulina rotulata (fig. 9j), lenticulina sp., neoflabelina reticulata (fig. 9i), oridorsalis umbonatus, serovaina complanata, cibicidoides sp., nodosaria sp., and agglutinated spiroplectammina sp. the proportion of small benthic foraminifera significantly decreases and they make up only 10% of the microfossil assemblage. lithology and palaeoenvironment. marl and argillaceous limestone (mudstone/wackestone) with high proportions of planktonic species (up to 90%) imply continuous deepening of this marine realm and deposition in outer shelf to upper bathyal environments. biozone viii: racemiguembelina fructicosa zone (figs. 8b–e) definition. partial range zone from the lo of race miguembelina fructicosa to the lo of abathomphalus mayaroensis (huber et al., 2008; perez­rodríguez et al., 2012) age. early maastrichtian interval. al mahr­1 (30–35 m, figs. 2 and 4), palmyra­1 (25–30 m, figs. 3, 4) assemblage characteristics. beside the nominate species racemiguembelina fructicosa (fig. 8e), planoglobulina acervulinoides and pseudotextularia elegans are also recorded for the first time in the lower part of this biozone. in the same horizons contusotruncana fornicata and c. plummerae have their ho. dominant species in the assemblage are heterohelix globulosa, h. striata and h. navarroensis. common species include rugoglobigerina rugosa and r. macrocephala. the planktonic foraminiferal assemblage is similar to that in biozone vii (41 species) and consists of the following species: abathomphalus intermedius, archaegeologia croatica 67/2geologia croatica 98 figure 7: sem photomicrographs of selected planktonic foraminifera observed in contusotruncana plummerae zone (biozone iv, a, b), biozone v (c–g), globotruncanella havanensis zone (biozone vi, h–j) and pseudoguembelina palpebra (biozone vii, k–p). a globigerinelloides bollii, al mahr-1, interval 95– 100 m. b archaeoglobigerina blowi, al mahr-1, interval 85–90 m. c pseudotextularia nuttalli, al mahr-1, interval 80–85 m. d rugoglobigerina rugosa, al mahr-1, interval 80–85 m. e, f globotruncana arca (e), and detail of the wall texture (f), palmyra-1, interval 75–80 m. g globigerinelloides prairiehillensis, palmyra-1, interval 75–80 m. h globotruncanella havanensis, palmyra-1, interval 65–70 m. i, j heterohelix navarroensis (i), and detail of the wall texture (j), palmyra-1, interval 60–65 m. k rugoglobigerina hexacamerata, al mahr-1, interval 65–70 m. l rugoglobigerina rugosa, al mahr-1, interval 65–70 m. m pseudoguembelina costulata, al mahr-1, interval 60–65 m. n pseudoguembelina palpebra, palmyra-1, interval 50–60 m. o, p gansserina gansseri, al mahr-1, interval 45–50 m (o), and palmyra-1, interval 40–50 m (p). pecimotika et al.: planktonic foraminiferal biostratigraphy and paleoecology of upper cretaceous deposits from the palmyride region, syria geologia croatica 99 oglobigerina blowi, a. cretacea, contusotruncana fornicata, gansserina gansseri, globotruncana arca, g. bulloides, g. linneiana, g. hilli,globotruncanella havanensis, g. minuta, g. petaloidea (fig. 8b), globotruncanita conica, g. stuarti, g. stuartiformis (figs. 8c, d), g. pettersi, guembelitria turrita, g. cretacea, heterohelix labellosa, h. planata, h. punctulata, globigerinelloides bollii, g. prairiehillensis, g. subcarinatus, laeviheterohelix dentata, l. glabrans, mu ricohedbergella holmdelensis, m. mounmothensis, muricohedbergella sp., planoglobulina carseyae, pseudoguembelina costulata, p. excolata, p. kempensis,p. palpebra, pseudotextularia nuttalli, p. intermedia, rugoglobigerina hexacamerata, and racemiguembelina powelli. representatives of the genus heterohelix increase in abundance to 38%, and rugoglobigerinids are more common here than in the underlying biozones and make up to 14% of the planktonic foraminiferal association. pseudoguembelinids that reached a peak in the previous biozone drop in abundance to 8%, and globotruncanids also decrease in occurrence towards to the top of biozone vii. small benthic foraminifera comprise less than 10% of the assemblage and include bolivina incrassata, gavelinella monterelensis, gavelinella sp., gyroidinoides globosus, lenticulina rotulata, lenticulina sp., neoflabelina reticulata, stensioeina pommerana (figs. 9k, l), cibicidoides sp., and agglutinated species gaudryina laevigata. lithology and palaeoenvironment. marl and argillaceous limestone (mudstone/wackestone) contain a high proportion of rich and very well preserved planktonic foraminifera suggesting deposition in upper to middle bathyal environments. biozone ix: abathomphalus mayaroensis zone (figs. 9f–p) definition. interval zone from the lo of the nominal taxon to the extinction of most of the cretaceous planktonic foraminifera (premoli silva & sliter, 1994; robaszyn ski & caron, 1995; robaszynski et al., 2000; premoli silva & verga, 2004; chacon et al., 2004) age. late maastrichtian interval. al mahr­1 (10–30 m, figs. 2 and 4), palmyra­1 (5–25 m, figs. 3, 4) assemblage characteristics. the zonal marker abathomphalus mayaroensis (figs. 8f, m, n) is represented by a few specimens. very common species in the planktonic fora miniferal assemblages include heterohelix globulosa, h. striata, rugoglobigerina rugosa, heterohelix navarroensi, h. planata and muricohedbergella mounmouthensis, while common species include heterohelix labellosa, globotruncana arca, rugoglobigerina macrocephala and muricohedbergella holmdelensis. this very well preserved and highly diverse assemblage also contains other species such as globotruncana hilli, globotruncanella havanensis, g. minuta, g. petaloidea, g. pschade, globotruncanita conica (fig. 8p), g. stuarti, g. stuartiformis (figs. 8k, l), g. pettersi, guembelitria cretacea, heterohelix punctulata, pseudoguembelina excolata (figs. 8g, h), p. kempensis, p. palpebra, pseudotextularia elegans (figs. 8i, j), p. intermedia, p. nuttalli, planoglobulina carseyae, and rugoglobigerina hexacamerata. a large overturn in planktonic fauna occurred within bio zone ix due to the extinction and disappearance of many species at the base of the biozone, including: archaeoglobigerina blowi, a. cretacea, globotruncana bulloides and globigerinelloides prairiehillensi.furthermore, species such as abathom phalus intermedius (fig. 8o), gansserina gansseri, glo botruncana linneiana, pseudoguembelina costulata and racemiguembelina powelli become rare and then disappear in the middle part of biozone ix. species of the genus heterohelix remain the dominant group in the planktonic assemblage with the same abundance of 36%, whereas globotruncanids and rugoglobigerinids have almost the same abun dance as in the underlying biozone viii. the very high overall diversity (40 species) of biozone ix, although somewhat lower than in biozone viii, dramatically decreases at the end of the zone when most planktonic foraminiferal species become extinct. only a few species such as muricohedbergella holmdellensis, m. monmouthensis and guembelitria cretacea cross the cretaceous/palaeogene boundary. the calcareous benthic species bolivinoides draco (fig. 9p) is also characteristic of abathomphalus mayaroensis zone (gawor­biedowa, 1984). in addition to this species, many other small benthic foraminifera also occur: bolivina incrassata, gyroidinoides globosus (fig. 9n), lenticulina rotulata, l. münsteri, neoflabelina reticulata, stensioeina pommerana, cibicidoides sp. (fig. 9m) as well as agglutinated forms gaudryina laevigata (fig. 9o) and spiroplectammina sp. lithology and palaeoenvironment. marl, argillaceous limestone (mudstone/wackestone) and slightly dolomitized limestone (foraminiferal wackestone) contain rich and very well preserved foraminiferal assemblages (plankton/benthos ratio is 94:6), suggesting a permanent open­marine influence and deposition in upper to middle bathyal environments. 5. interpretation and discussion this detailed study of the late turonian–maastrichtian planktonic and benthic foraminiferal assemblages provides the ba sis for biostratigraphic and palaeoenvironmental interpretations of the successions examined. a total of 56 planktonic foraminiferal species belonging to 20 different genera have been identified. abundant and moderately to highly diverse and generally well preserved planktonic foraminiferal assemblages enabled biozonation and identification of the following biozones: biozone i, biozone ii, biozone i, iv contusotruncana plummerae zone, biozone v, vi globo truncanella ha va nensis zone, vii pseudoguembelina palpebra zone, viii racemiguembelina fructicosa zone and ix abathomphalus mayorensis zone. identification of possible stratigraphic gaps in the upper cretaceous successions examined here was very difficult because the drill cuttings were sampled every 5–10 metres. according to brew (2001), the upper cretaceous strata succession of the palmyride area is characterized by progressively deeper water environments. evidence for some minor compression and uplift has been documented for the latest cretaceous of this area, together with an associated minor sedimentary hiatus at the cretageologia croatica 67/2geologia croatica 100 figure 8: sem photomicrographs of selected planktonic foraminifera observed in the pseudoguembelina palpebra zone (biozone vii, a) racemiguembelina fructicosa zone (biozone viii, b–e) and abathomphalus mayaroensis zone (biozone ix, f–p). a rugoglobigerina rugosa, palmyra-1, interval 40–50 m. b globotruncanella petaloidea, al mahr-1, interval 30–35 m. c, d globotruncanita stuartiformis (c), and detail of the wall texture (d), al mahr-1, interval 30–35 m. e racemiguembelina fructicosa, palmyra-1, interval 25–30 m. f abathomphalus mayaroensis, al mahr-1, interval 30–35 m. g, h pseudoguembelina excolata (g), and detail showing wall texture (h), palmyra-1, interval 20–25 m. i, j pseudotextularia elegans (i), and detail showing wall texture (j), palmyra-1, interval 20–25 m. k, l globotruncanita stuartiformis, al mahar-1, interval 20–25 m. m, n abathomphalus mayaroensis, al mahr-1, interval 15–20 m (m), and palmyra-1, interval 10–20 m (n). o abathomphalus intermedius, palmyra-1, interval 10–20 m. p globotruncanita conica, palmyra-1, interval 10–20 m. pecimotika et al.: planktonic foraminiferal biostratigraphy and paleoecology of upper cretaceous deposits from the palmyride region, syria geologia croatica 101 figure 9: sem photomicrographs of selected benthic foraminifera observed in the upper turonian–maastrichtian sequence of the palmyride region. a, b gavelinella sp., al mahr-1, interval 185–190 m (a), and palmyra-1, interval 180–190 m. c gavelinella monterelensis, al mahr-1, interval 115–120 m. d bulimina ovulum, al mahr-1, interval 150–155 m. e bulimina sp., palmyra-1, interval 130–140 m. f lenticulina sp., palmyra-1, interval 90–100 m. g spiroplectammina sp., al mahr-1, interval 70–80 m. h cibicidoides sp., palmyra-1, interval 65–75 m. i neoflabelina reticulata, palmyra-1, interval 50–60 m. j lenticulina rotulata, al mahr-1, interval 45–50 m. k, l stensioeina pommerana, al mahr-1, interval 25–30 m. m cibicidoides sp., palmyra-1, interval 15–25 m. n gyroidinoides globosus, palmyra-1, interval 15–25 m. o gaudryna laevigata, al mahr-1, interval 15–20 m. p bolivinoides draco, palmyra-1, interval 10–20 m. geologia croatica 67/2geologia croatica 102 ceous/palaeogene boundary (brew, 2001). to the northeast of the palmyride area, however, a widespread unconformity has been documented for the turonian–coniacian. according to brew (2001), during the campanian and early maastrichtian in the palmyride area of syria, progressively deeper water carbonate facies and pelagic marly limestones of the shiranish formation were deposited. a significant period of late cretaceous deformation in northeastern syria began in the latest campanian or earliest maastrichtian (brew, 2001). the boundary between the soukhne (massive limestone) formation and the syn-extensional shiranish formation is unconformable, suggesting a major pre-extensional stratigraphic hiatus in that area. the foraminiferal assemblage of biozone i (late turonian–early santonian, upper part of the judea formation; figs. 2–5 and 10) is moderately preserved. this biozone may corespond to the dicarinella concavata zone, and is characterized by the lo of gobigerinelloides bollii and contusotruncana fornicata, as well as by abundant heterohelix reussi, h. globulosa and h. moremani. opportunistic (r-strategists) biserial taxa heterohelicids and globular archeoglobigerinids (premoli silva & sliter, 1999; petrizzo, 2002, 2003) are important components in this biozone. the dominant species heterohelix globulosa inhabits subsurface levels in the water column (abramovich et al., 2003). domination of opportunistic biserial heterohelicids and other genera with simple morphology (muricohedbergella, pseudotextularia, archeoglobigerina and whiteinella), which comprise up to 87 % of the total planktonic foraminiferal assemblage, indicate palaeoceanographic conditions favorable for opportunistic (r-strategist) organisms, such as a high productivity ocean with generally cooler but fluctuating climate, well developed oxygen minimum zone, common up-wellings and cyclic eutrophications of the surface water (boersma & premoli silva, 1989; nederbragt et al., 1998; petrizzo, 2002). on the other hand, the occurrence of k-strategists (dicarinella and marginotruncana), although present in a smaller percentage in the planktonic assemblage, indicates warm stable episodes with oligotrophic oceanic conditions and well developed water column stratification, which are favourable for these two groups with more complex test architecture (petrizzo, 2002). almost equal proportions of small benthic and planktonic foraminifera in limestones (mudstone/wackestone to foraminiferal wackestone) and marl suggest deposition in outer shelf environments (olsson & nyong, 1984; boersma, 1988; murray, 1991; gräfe, 2005 the most important characteristic of biozone ii (middle–late santonian, the soukhne formation; figs. 2–5 and 10) is the high level of speciation of planktonic foraminifera. this biozone is determined by the first appearance of several new taxa including globotruncana linneiana, g. arca, g. bulloides, g. hilli, hendersonites carinatus, heterohelix planata, h. punctulata, h. striata, globigerinelloides prairiehillensis, and globotruncanita stuartiformis, which may suggest the dicarinella asymetrica zone. the foraminiferal assemblage is moderately diverse and better preserved relative to biozone i. heterohelicids experienced speciation during this biozone; their abundance increased to 46.5%, and they remained a dominant group until the end of the cretaceous. as opportunistic planktonic foraminifera heterohelicids inhabit more nutrient-rich waters and are indicators of cooler and unstable environments (nederbragt, 1991; nederbragt et al., 1998; petrizzo, 2002). their speciation is most likely induced by a somewhat cooler but variable climate and anoxic events during the middle santonian. beside heterohelicids, other small-sized forms with simple test-morphology, such as muriciohedbergellids, archeoglobigerinids and globigerinelloids, are very common in the planktonic assemblage. all of these groups belong to opportunistic taxa that have a great reproductive potential in eutrophic and somewhat mesotrophic environments with a very well developed oxygen minimum layer (nederbragt, 1991). small-sized heterohelicids indicate expansion of the oxygen minimum zone (omz) due to increased surface water productivity and depletion of oxygen in subsurface waters by oxidation of organic carbon (leckie, 1987; leckie et al., 1998; keller & pardo, 2004; pardo & keller, 2008; ashckenazi­polivoda et al., 2011). heterohelicidae were found to be very common in most of the omz suggesting high productivity and/or some tolerance to subsurface oxygen depletion (ashckenazi-polivoda et al., 2011). in addition, abundant phosphate grains in the upper part of this zone, support the interpretation that biozone ii was characterized by high palaeoproductivity, relatively constant and high food supply and moderate increase in bottom water aeration. very high productivity during this biozone was supported by a fluctuating climate and up­welling cycles, which brought nutrient-rich water into the environments inhabited by heterohelicids and upper-middle bathyal benthic foraminifera. at the upper boundary of biozone ii all dicarinellids and whiteinellids became extinct. the proportion of planktonic species increased and reached up to 60% of the microfossil assemblage present in foraminiferal mudstone/wackestone, marl and dolomitic limestones that represent an open marine, most probably outer shelf environments (olsson & nyong, 1984; boersma, 1988; murray, 1991; gräfe, 2005). biozone iii (early campanian, the soukhne formation; figs. 2–5 and 10) is marked by the disappearance of marginotruncanids in its base and by the lo of pseudoguembelina costulata and rugloglobirerina rugosa. this planktonic assemblage may correspond to the globotruncanita elevata zone. planktonic and benthic foraminiferal assemblages are rich and moderately to well preserved. the proportion of planktonic species reaches up to 65% and indicates further deepening of this realm (boersma, 1988; murray, 1991; gräfe, 2005; darvishzad & abdolalipour, 2009). the most common species are opportunistic (r­strategists) taxa: hendersonites carinatus, heterohelix punctulata, h. striata and pseudotextularia nuttalli. although characterized by different deposits, i.e., limestone (foraminiferal mudstone/wackestone) and calcareous marl, relative to biozone ii, the deposition of these strata continued within the same open marine, probably outer shelf settings. pecimotika et al.: planktonic foraminiferal biostratigraphy and paleoecology of upper cretaceous deposits from the palmyride region, syria geologia croatica 103 phosphate grains are very common in dolomitic limestones from the upper part of biozone ii in al mahr-1 (figs. 2 and 4), and in the uppermost part of biozone ii and the lowermost part of biozone iii in palmyra­1 (figs. 3, 4). abundant phosphate grains generally indicate some very specific geological and palaeoenvironmental conditions, such as oxygen deficiency, upwelling conditions, and transgressive intervals (haq et al., 1987; reiss, 1988; almogi­labin et al., 1993; widmark & speijer, 1997; jarvis et al., 2002; pufhal et al., 2003; soudry et al., 2006; ashckenazi­polivoda et al., 2011). it is possible that such palaeoceanographic conditions, especially upwelling, increased food supply and primary production in the surface and subsurface marine environments, and thus also indirectly affected higher production and domination of oportunistic (r-strategists) planktonic foraminiferal species during biozones ii and iii. the lowest occurrence of laeviheterohelix glabrans and muricohedbergella mounmouthensis and rare contusotruncana plummerae in the planktonic foraminiferal assemblage of biozone iv (middle–late campanian, the shiranish formation; figs. 2–5 and 10) suggest the contusotruncana plummerae zone. this biozone has been appointed by petrizzo et al. (2011) for the lower–middle campanian of tropical and subtropical areas because of the difficulties in using the first occurrence datum of globotruncana ventricosa in low latitude successions from the tethyan realm. species of the genus heterohelix dominated in the previous biozone iii but decrease to 32.5% in biozone iv, whereas the abundance of two genera muricohedbergella and pseudoguembelina significantly increases up to 15% and 10.5%, respectively. although the opportunistic (r-strategists) species are still dominant, the specialized taxa (k-strategists) such as globotruncanids (premoli silva & sliter, 1999; petrizzo, 2002; dubicka & peryt, 2012) increase in the overall number of species and also slightly increase in abundance within this planktonic assemblage. this indicates mesotrophic to more oligotrophic environmental conditions that are favorable for keeled globotruncanids. the well-preserved foraminiferal assemblage and high proportion of planktonic foraminifera (70%) in the argillaceous limestones marl and calcareous marls of biozone iv suggest an open marine, probably outer shelf to upper bathyal environment (boersma, 1988; murray, 1991; gräfe, 2005). the lowest occurrence of planktonic foraminifera laeviheterohelix dentata, globotruncanella havanensis and globotruncanita stuarti in biozone v (late campanian, the shiranish formation; figs. 2–5 and 10) may suggest the radotruncana calcarata zone. the well-preserved foraminiferal assemblage is rich, diverse and has an increased number of k-strategists (keeled globotruncanids; premoli silva & sliter, 1999). globotruncanids have a complex test morphology and usually inhabit the subsubsurface water column (petrizzo, 2002; abramovich et al., 2003; dubicka & peryt, 2012), which implies good stratification of the water column and a tropical to subtropical climate during the late campanian (leckie, 1989; huber et al., 1995; darvishzad & abdolalipour, 2009). deposits and sedimentary settings remain the same as for biozone iv, i.e., deep-water marine environments. the zonal marker globotruncanella havanensis is relatively rare in biozone vi (late campanian, the shiranish formation; figs. 2–5 and 10), and the base of this biozone is indicated by the lo of pseudoguembelina excolata, planoglobulina carseyae and rugoglobigerina hexacamerata. the foraminiferal assemblage is rich and well preserved. although the opportunistic group heterohelicids stay dominant group in the planktonic assemblage with 37.5% abundance, k-strategists, such as keeled globotruncanids, become an important component in the planktonic foraminiferal assemblage with 9 species and 13.5% abundance. these point to stable environmental conditions, such as an oligotrophic ocean with a tropical to subtropical climate, well stratified water column, stable thermocline and other favourable palaeoceanographic parameters for r/k and k-selected group of planktonic foraminifera (leckie, 1989; murray, 1991; darvishzad & abdolalipour, 2009). abundance of species from the genus globigerinelloides and muricohedbergella (r-selected forms) show inverse trends in comparison with the previous biozones and decrease to 7.5% and 6%, respectively (fig. 10). the proportion of planktonic species increased and reached up to 85% of the microfossil assemblage present in marl and argillaceous limestone (mudstone/wackestone) that represent an open marine, outer shelf to upper bathyal environments (olsson & nyong, 1984; boersma, 1988; murray, 1991; gräfe, 2005). the pseudoguembelina palpebra zone (biozone vii, late campanian–early maastrichtian, the shiranish formation; figs. 2–5 and 10) is characterized by the lo of p. palpebra, which is consistently found throughout the interval in moderate abundance. also, the lowest occurrence of globotruncanella pschadae, pseudoguembelina kempensis and racemiguembelina powelli is recorded in the lower part of this biozone. gansserina gansseri is very rare and poorly preserved in the investigated samples, and therefore p. palpebra serves as a better zonal marker for the uppermost campanian, as also reported by huber at al. (2008) from subtropical north atlantic (blake nose). the planktonic foraminiferal assemblage of biozone vii is rich, very well preserved and in comparison with biozone vi, biodiversity throughout this interval significantly increases (to 41 species). opportunistic representatives of the genus heterohelix are still the dominant group in the planktonic assemblage with 34% abundance. also, the genus pseudoguembelina, known as a successful surface and subsurface dweller in tropical and subtropical open ocean (nederbragt, 1989; huber, 1992; abramovich et al., 2003), significantly increased in abundance up to17%. species of the genus pseudoguembelina are strongly photosymbiotic and their expansion is related to favourable palaeoecological conditions in the late cretaceous ocean, such as the presence of warm and oligotrophic surface ocean waters (d´hondt & zachos, 1998; abramovich et al., 2003). the proportion of planktonic foraminifera accounts for up to 90% of the microfossil assemblages found in marl and argillaceous limegeologia croatica 67/2geologia croatica 104 stone (mudstone/wackestone), which implies further deepening of this realm and deposition in outer shelf to upper bathyal environments (boersma, 1988; murray, 1991; gräfe, 2005; darvishzad & abdolalipour, 2009). the lowest occurrence of planktonic foraminifera planoglobulina acervulinoides and peudotextularia elegans in association with the rare zonal marker racemiguembelina fructicosa, is indicative of biozone viii (early–late maastrichtian, the shiranish formation; figs. 2–5 and 10). this biozone is characterised by a diverse and very well preserved planktonic foraminiferal assemblage with 41 species, similar to that from biozone vii. rugoglobigerinids increased in abundance and reached up to 14% of the assemblage, while representatives of the genus heterohelix still dominate the assemblage with 38%. species of the genus rugoglobigerina inhabit surface and subsurface habitats (abramovich et al., 2003), and are known as symbiotic organisms (d´hondt & zachos, 1998). speciation of planktonic foraminifera in this biozone is likely supported by good water column stratification and opening of new niches favourable for all groups of planktonic foraminifera. many subsurface dwellers, such as several species of the genus globotruncana, acquired adaptation to the thermocline habitat (abramovich et al., 2003). all of these changes correspond very well to the documented global sea level fluctuations and alternating cooler and warmer periods in the early to late maastrichtian (haq et al., 1987; fig. 5). during zone viii the sedimentary setting was a deep sea environment (upper bathyal), as a result of further deepening of this sedimentary realm. the planktonic foraminiferal assemblage of the latest cretaceous abathomphalus mayaroensis zone (biozone ix, late maastrichtian, the shiranish formation; figs. 2–5 and 10) is very similar to those in biozone viii and is rich in the overall number of species (39) as well as in the number of individuals. an important characteristic of this biozone is the increased number of k-strategist species of globotruncanids (15.5%), and planoglobulinids (4%), whereas rugoglobigerinids retained their abundance (14%). some opportunistic species of the genus muricohedbergella also show an increase and constitute 9% of the assemblage, while members of the genus globigerinelloides (2%) decrease in abundance (fig. 10). species of the genus heterohelix have an almost equal abundance (36%) compared to biozone viii. composition of the planktonic foraminiferal assemblage with a significantly higher percentage of k­strategist specialists, which inhabit subsurface and thermocline layers, indicates an oligotrophic ocean with a very well stratified water column supported by a stable thermocline (premoli silva & sliter, 1999; pearson et al., 2001; abramovich et al., 2003). on the other hand, the symbiont­bearing taxa rugoglobigerina, pseudoguembelina and heterohelix were very well adapted to surface and subsurface oligotrophic ocean water (d´hondt & zachos, 1998; pearson et al., 2001; abramovich et al., 2003). in the upper part of biozone ix, the decreased numbers of globotruncanid species indicate fluctuating climate, sea­level changes and up-welling cycles which could cause instability in the water column and unfavourable environmental conditions for k­strategists (abramovich & keller, 2002; haq et al., 1987). this high diversity abruptly decreases at the end of the biozone, when most planktonic foraminiferal species became extinct. marl, argillaceous limestone (mudstone/wackestone), and slightly dolomitized limestone (foraminiferal wackestone) contain rich and very well preserved foraminiferal assemblages, whereas planktonic foraminifera reach over 90% of the entire community suggesting deposition in upper bathyal environments (boersma, 1988; murray, 1991; gräfe, 2005; darvishzad & abdolalipour, 2009). all these facts indicate the late cretaceous as being a long, warm and relatively stable period with palaeoceanographic conditions favourable for all groups of planktonic foraminifera which inhabited different niches in a well stratified water column (leckie, 1989; huber et al., 1995; premoli silva & sliter, 1999; petrizzo, 2002, pearson et al., 2001; abramovich et al., 2003; dubicka & peryt, 2012). the soukhne formation (santonian–early campanian, biozones ii and iii, figs. 2–4) contains phosphate grains. similar phosphate deposits are widespread in many parts of the levantin region (i.e., israel, jordan, iraq, turkey and egypt; al maleh & mouty, 1994; pufhal et al., 2003; abed at al., 2005; baioumy & tada, 2005; soudry et al., 2006; ashckenazi­polivoda et al., 2011; schneider­mor et al., 2012). the phosphate deposits in syria formed in response to a high-productivity upwelling regime that persisted on the southern margins of the tethys during the late cretaceous (al maleh & mouty, 1994). the planktonic assemblages associated with phosphate grains in the palmyride strata are characterized by domination of opportunistic (r-strategists) taxa such as the genus heterohelix (biozone ii and iii, figs. 2, 3), which indicates a highly productive photic zone (reiss, 1988; almogi-labin et al., 1993; widmark & speijer, 1997; pufhal et al., 2003) and a low oxygen environment (ashckenazi-polivo da et al., 2011). the benthic assemblages found with phosphates have abundant specimens of the genus bulimina, which are commonly documented from highly productive, low-oxygen settings from around the world, including for example south america, morocco, egypt, jordan, iraq and israel (pufhal et al., 2003; ashckenazi­polivoda et al., 2011). an additional factor that contributed to the formation of phosphate was the enrichment in phosphorous from p-rich deep waters that upwelled in the palmyrida basin by currents flowing along the northern edge of the arabian platform (soudry et al., 2006). warming of the upwelled water and the abundance of nutrients caused the proliferation of plankton, which assimilated, stored and concentrated phosphate. after the deposition of plankton, a large amount of phosphate dissolved and became concentrated in the sea­floor sediments (al maleh & mouty, 1994). such high primary productivity and sea floor phosphogenesis prevailed mainly on the southeastern tethyan margins as a result of persistent upwelling circulation that recycled dissolved phosphorous from the intermediate-depth waters and distributed it to the photic zone (soudry et al., pecimotika et al.: planktonic foraminiferal biostratigraphy and paleoecology of upper cretaceous deposits from the palmyride region, syria geologia croatica 105 2006). the phosphates developed during transgressive periods that promoted carbonate sediment starvation. simple (internally homogenous) p2o5-enriched phosphate nodules probably replaced calcite nodule precursors in suboxic conditions as a result of processes that involved oceanic upwelling, exhumation and burial coupled with alternating oxic and suboxic conditions (marshall-neill & ruffell, 2004). the presence of phosphate is an important indicator of oxygen deficiency, upwelling conditions, transgressive intervals, and omission surfaces (trappe, 2001), and any future studies of this cretaceous stratigraphic interval should also include detailed analyses of the associated phosphate grains. 6. conclusions the stratigraphic analysis of the upper cretaceous strata from the palmyride area in syria included a detailed micropalaeontological investigation of foraminferal assemblages and rock types obtained from drill cuttings in two deep exploration wells (al mahr-1 and palmyra-1). nine biozones have been identified in the upper turonian to maastrichtian succession: biozone i, biozone ii, biozone iii, iv contusotruncana plummerae zone, biozone v, vi globotruncanella havanensis zone, vii pseudoguembelina palpebra zone, viii raceemiguembelina fructicosa zone, and ix abathomphalus mayorensis zone. during the late turonian to early campanian (biozone i to iii) in the investigated palmyride strata, domination of opportunistic taxa (heterohelix, globigerinelloides, archaeoglobigerina, and muricohedbergella) implies upwelling, low oxygen conditions and subtropical climate. on the other hand, the rich and highly diversified planktonic assemblages (biozone iv to ix) with many k-selected taxa (i.e., ornamented keeled globotruncanids, rugoglobigerinids, planoglobulinids, pseudoguembelinids) indicate a tropical to subtropical climate and well­stratified water column during the late campanian and into the maastrichtian. in the upper part of biozone ix, the decreased numbers of globotruncanid species indicate a less stratified water column and unfavourable environmental conditions for k-strategists. a dramatic faunal turnover at the end of this biozone is marked by the extinction of most planktonic foraminifera, with only a few species (e.g., muricohedbergella holmdelensis, m. montmouthensis and guembelitria cretacea) present across the cretaceous/palaeogene boundary. phosphate grains are very common in dolomitic limestone of the upper part of biozone ii in al mahr-1 and in the uppermost part of biozone ii and lowermost part of biozone iii in palmyra-1 (soukhne formation). the phosphate occurrence helps improve the late santonian–early campanian stratigraphic interpretation of this interval because similar deposits occur during this time period elsewhere along the southeastern margins of tethys (israel, jordan, iraq, turkey and egypt). the presence of phosphate in the study area indicates oceanic upwelling that caused increased food supply and influenced higher primary marine production, and thus indirectly affected higher production and domination of oportunistic planktonic foraminifera in biozones ii and iii. acknowledgment we thank bosiljka glumac (smith college) whose comments and suggestions improved this paper, morana hernitz­kučenjak (ina­industrija nafte d.d.) for discussion and tehnical support, robert košćal (university of zagreb) for technical assistance, renata slavković (ina-industrija nafte d.d.) for sem photomicrografs of foraminifera, vladimir veseli and ivan a. mesić (ina­industrija nafte d.d.) for sharing well report data. we are grateful to brian t. huber (smithsonian institution) and bilal sari (dokuz eylül university) for carefully reviewing the figure 10: percentage of late cretaceous genera in the planktonic foraminiferal assemblages from the study area in syria. geologia croatica 67/2geologia croatica 106 manuscript and enabling us to significantly improve it. this research was supported by ina-industrija nafte d.d. zagreb, who also provided samples from the syrian wells. references abed, a.m., arouri, k.r. & boreham, c.j. (2005): source rockpotentional of the phosphorite bituminous chalk-marlsequence in jordan.– marine and petroleum geology, 22, 413–425. abramovich, s. & keller, g. (2002): high stress late maastrichtian palaeoenvironment: inference from planktonic foraminifera in tunisia.– palaeogeography, palaeoclimatolology, palaeoecology, 178, 145–164. abramovich, s., keller, g., stüben, d. & berner, z. (2003): characterization of late campanian and maastrichtian plank tonic foraminiferal depth habitats and vital activities based on stable isotopes.– palaeogeography, palaeoclimatolology, palaeoecolo gy, 202, 1–29. al maleh, a.k.h. & mouty, m. (1994): lithostratigraphy of senonian phosphorite deposits in the palmyridean region and their general sedimentological and paleogeographic framework. –in: lijima, a., abed, a. m. & garrison, e. p. (eds.): siliceous, phosphatic and glauconitic sediments of the tertiary and mesozoic.– proceedings, part c, 29th international geological congress, tokyo, brill academic publishers, 225–232. almogi­labin, a., bein, a. & sass, e. (1993): late cretaceous upwelling system along the southern tethys (israel): interrelationship between productivity, bottom water environments, and organic matter preservation.– paleooceanography, 8, 671–690. ashckenazi-polivoda, s., abramovich, s., almogi-labin, a., schneider-mor, a., feinstein, s., püttmann, w. & berner, z. (2011): palaeoenvironments of the latest cretaceous oil shale sequence, sothern tethys, israel, as an integral part of the prevailing upwelling system.– palaeogeography, palaeoclimatolology, palaeoecology, 305, 93–108. babazadeh, s.a., robaszynski, f. & courme, m.d. (2007): new biostratigraphic data from cretaceous planktonic foraminifera in sahlabad, eastern iran.– geobios, 40, 445–454. baioumy, h. & tada, r. (2005): origin of late cretaceous phosphorites in egypt.– cretaceous research, 26, 261–275. boersma, a. (1988): foraminifera.– in: haq, b.u. & boersma, a. (eds.): introduction to marine micropaleontology.– elsevier science, singapore, 19–78. boersma, a. & premoli silva, i. (1989): atlantic paleogene biserial heterohelicid foraminifera and oxygen minima.– paleooceanography, 4/3, 271–286. bolli, h.m., beckmann, j.p. & saunders, j.b. (1994): benthic foraminifera biostratigraphy of the south caribbean region.– cambridge university press, cambridge, 408 p. brew, g.e. (2001): tectonic evolution of syria interpreted from integrated geophysical and geological analysis.– phd thesis, cornell university, ithaca, new york, 323 p. brew, g.e., barazangi, m., al-maleh, a.k. & sawaf, t. (2001): tectonic and geologic evolution of syria.– geoarabia, 6/4, 573–616. caron, m. (1985): cretaceous planktonic foraminifera.– in: bolli, h.m., saunders, j.b. & perch nielsen, k. (eds.): planktonic stratigraphy.– cambridge university press, cambridge, 17–86. chacón, b., martín­chivelet, j. & gräfe, k.u. (2004): latest santonian to latest maastrichtian planktonic foraminifera and biostratigraphy of the hemipelagic succession of the prebetic zone (murica and alicante provinces, south-east spain).– cretaceous research, 25, 585–601. dacer, g., stanković, d., mesić, i.a. & ivaniček, z. (2007): upper campanian to maastrichtian foraminiferal assemblages of the palmyra region, syria.– geophysical research abstracts, cd, european geosciences union, vienna. darvishzad, b. & abdolalipour, s. (2009): campanian and maastrichtian biostratigraphy and palaeoenvironment in jorband section, north of iran.– journal of sciences, islamic republic of iran, 20/1, 23–29. d´hondt, s. & zachos, j.c. (1998): cretaceous foraminifera and the evolutionary history of planktonic photosymbiosis.– paleobiology, 24/4, 512–523. dubicka, z. & peryt, d. (2012): latest campanian and maastrichtian palaeoenvironment changes: implications from an epicontinental sea (se poland and western ukraine).– cretaceous research, 37, 272–284. evamy, b. d. & shearman, d.j. (1962): the application of chemical staining techniques to the study of diagenesis of limestones.– proceedings of the geologycal society, london, 1599, 102 p. flügel, e. (2004): microfacies of carbonate rocks: anlysis, interpretation and application.– springer, berlin, 976 p. föllmi, k.b. (1996): the phosphorous cycle, phosphogenesis and marine phosphate­rich deposits.– earth science reviews, 40, 55–124. gardin, s., galbrun, b., thibault, n., coccioni, r. & premoli silva, i. (2012): bio­magnetochronology for the upper cam panian–maastrichtian from gubbio area, italy: new results from the contesa highway and bottacione sections.– newsletters on stratigraphy, 45/1, 75–103. gasiński, m.a. & uchman, a. (2009): latest maastrichtian fora­ mi niferal assemblages from the husów region (skole nappe, outer carpathians, poland).– geologia carpathica, 60/4, 283–294. gawor­biedowa, e. (1984): foraminiferal zonation of the upper cretaceous deposits in poland (except for the carpathians and sudeten).– second international symposium of benthic foraminifera, pau, 1983 (benthos′83), revue de paléobiologie, volume spécial, 1, 213–233. glenn, c.r., föllmi, k.b., riggs, s.r., baturin, g.n., grimm, k.a., trappe, j., abed, a.m., galli-olivier, c., garrison, r.e., ilyin, a.v., jehl, c., rohrlich, v., sadaqah, r.m., schidlowski, m., sheldon, r.e. & siegmun, h. (1994): phosphorous and phosphorites: sedimentology and environments of formation.– eclogae geologicae helvetiae, 87/3, 747–788. gräfe, k.u. (2005): late cretaceous benthic foraminifers from the basque-cantabrian basin, northern spain.– journal of iberian geology, 31/2, 277–298. hampton, m.j., bailey, h.w., gallagher, l.t., mortimore, r.n. & wood, c.j. (2007): the biostratigraphy of seaford head, sussex, southern england; an international reference section for the basal boundaries for the santonian and campanian stages in chalk facies.– cretaceous research, 28, 46–60. haq, b.u., hardenbol, j. & vail, p.r. (1987): chronology of fluc­ tua ting sea levels since triassic.– science, 235, 1156–1167. hemleben, c., spindler, m. & anderson, o.r. (1989): modern planktonic foraminifera.– springer­verlag, new york, 363 p. hernitz kučenjak, m., premec fućek, v., slavković, r. & mesić, i.a. (2006): planktonic foraminiferal biostratigraphy of the late eocene and oligocene in the palmyride area, syria.– geologia croatica, 59/1, 19–39. hillgartner, h. (1998): discontinuity surfaces on a shallowmarine carbonate platform (berriasian, valanginian, france and switzerland).– journal of sedimentary research, section b: stratigraphy and global studies, 68, 1093–1108. pecimotika et al.: planktonic foraminiferal biostratigraphy and paleoecology of upper cretaceous deposits from the palmyride region, syria geologia croatica 107 huber, b.t. (1992): paleobiogeography of campanian–maastrichtian foraminifera in the high southern latitudes.– palaeogeography, palaeoclimatolology, palaeoecology, 92, 325–360. huber, b.t., hodell, d.a. & hamilton, c.r. (1995): middle– late cretaceous of the southern high latitudes: stable isotopic evidence for minimal equator-to-pole thermal gradients.– geological society of america bulletin, 107, 1164–1191. huber, b.t., macleod, k. g. & tur, n. a. (2008): chronostratigraphic framework for upper campanian-maastrichtian sediments on the blake nose (subtropical north atlantic).– journal of foraminiferal research, 38, 162–182. inan, s., ugur, f.a., inan, t., yalcin, m.n. & mann, u. (2010): relationship between organic matter, sulphur and phosphate contents in upper cretaceous marine carbonates (karabogaz formation, se turkey): implication for early oil generation.– journal of petroleum geology, 34, 319–337. ismail, a.a. (1992): maastrichtian­early eocene benthonic foraminiferal biostratigraphy and palaeoecology of west central sinai, egypt.– m.e.r.c. ain shams university, earth science series, 6, 139–150. ismail, a.a., hussein-kamel, y., boukhary, m. & ghan dour, a.a.a. (2007): campanian­early eocene stratigraphy of the southern galala plateau, eastern desert, egypt.– geologia croatica, 60/2, 115–137. jarvis, i., mabrouk, a., moody, r. t. j. & cabrera, s. (2002): late cretaceous (campanian) carbon isotope events, sea-level change and correlation of the tethyan and boreal realms.– palaeogeography, palaeoclimatolology, palaeoecology, 188, 215–248. kaiho, k. (1998): phylogeny of deep-sea calcareous trochospiral benthic foraminifera: evolution and diversification.– micropaleontology, 44/3, 291–311. keller, g. & pardo, a. (2004): disaster opportunists guembelitrinidae: index for environmental catastrophes.– marine micropaleontology, 53, 83–116. leckie, r.m. (1987): paleoecology of mid­cretaceous planktonic foraminifera: a comparison of open ocean and epicontinental sea assemblages.– micropaleontology, 33, 164–176. leckie, r.m. (1989): a paleocenographic model for the early evolutionary history of planktonic foraminifera.– palaeogeography, palaeoclimatolology, palaeoecology, 73, 107–138. litak, r.k., barazangi, m., brew, g., sawaf, t. &alyoussef, w. (1998): structure and evolution of the petroliferous euphrates graben system, southeast syria.– american association of petroleum geologists bulletin, 82/6, 1173–1190. loeblich, a. r. & tappan, h. (1988): foraminiferal genera and their classification, treatise on invertebrate paleontology.– van nos trand reinhold, 970 p. lučić, d. & foršek, g. (2000): palmyride evolution: geologic, stratigraphic and structural overview (central syria).– in: vlahović, i. & biondić, r. (eds.): proceedings.– second croatian geological congress, cavtat, croatia, 311–316. lučić, d. (2001): litostratigraphical and petrographical guidebook of the typical facies in the wider area of hayan block (palmyrides, syria).– ina report, damascus, syria, 47 p. lučić, d., maretić, s., foršek, g., takač, d. & mesić, i. a. (2002): mesozoic carbonate facies and reservoirs in central palmyrides, syria.– abstract, cd, american association of petroleum geologists conference, cairo. ly, a. & kuhnt, w. (1994): late cretaceous benthic foraminiferal assemblages of the casamance shelf (senegal, nw africa): indication of a late cretaceous oxygen minimum zone.– revue de micropaléontologie, 37/1, 49–74. marshall­neill, g. & ruffell, a. (2004): authigenic phospha­ te nodules (late cretaceous, northern ireland) as condensed succession microarchives.– cretaceous research, 25, 439–452. mouty, m. & al­maleh, k. (1983): the geological study of the palmyridian chain using ideal geological sections for exploration purposes and geological survey.– general establishment of geology and mineral resources, ministry of petroleum and mineral re sour ces, damascus, syria, 950 p. murray, j.w. (1991): ecology and distribution of planktonic foraminifera.– in: lee, j.j. & anderson, o.r. (eds.): biology of foraminifera.– academic press, london, 255–285. nederbragt, a.j. (1989): maastrichtian heterohelicidae (planktonic foraminifera) from the north west atlantic.– journal of micropaleontology, 8, 183–206. nederbragt, a.j. (1991): late cretaceous biostratigraphy and development of heterohelicidae (planktonic foraminifera).– micropaleontology, 37/4, 329–372. nederbragt, a.j., erlich, r.n., fouke, b.w. & ganssen, g.m. (1998): palaeoecology of the biserial planktonic foraminifer heterohelix moremani (cushman) in the late albian to middle turonian circum-north atlantic.– palaeogeography, palaeoclimatolology, palaeoecology, 144, 115–133. ogg, j. g., ogg, g. & gradstein, f. m. (2008): the concise geologic time scale.– cambridge university press, new york, 185 p. olsson, r.k. & nyong, e.e. (1984): a paleoslope model for campanian-lower maastrichtian foraminifera of new jersey and delaware.– journal of foraminiferal research, 14, 50–69. olsson, r.k. & wise, s.w. (1987): upper maastrichtian to middle eocene stratigraphy of the new jersey slope and costal plain.– in: van hinte, j.e. & wise, s.w. (eds.): initial reports of the deep sea drilling project, 93, 1243–1365. pardo, a. & keller, g. (2008): biotic effects of environmental catastrophes at the end of the cretaceous and eary tertiary: guembelitria and heterohelix blooms.– cretaceous research, 29, 1058–1073. pérez­rodrígez, i., lees, j.a., larrasoana, j.c., arz, j.a. & arenillas, i. (2012): planktonic foraminiferal and calcareous nannofossil biostratigraphy and magnetostratigraphy of the uppermost campanian and maastrichtian at zumaia, northern spain.– cre taceous research, 37, 100–126. pearson, p.n., ditchfield, p.w., signano, j., harcourtbrown, k.g., nicholas, c.j., olsson, r.k., shackleton, n.j. & hall, m.a. (2001): warm tropical sea surface temperatures in the late cretaceous eocene epochs: nature, 413, 481–487. petrizzo, m.r. (2002): palaeoceanographic and palaeoclimatic inferences from late cretaceous planktonic foraminiferal assemblages from the exmouth plateau (odp sites 762 and 763, eastern indian ocean).– marine micropaleontology, 45, 117–150. petrizzo m. r. (2003): late cretaceous planktonic foraminiferal bioevents in the tethys and in the southern ocean record: an overview.– journal of foraminiferal research, 23, 330–337. petrizzo m. r., falzoni, f. & premoli silva, i. (2011): identification of the base of the lower­to­middle campanian globotruncana ventricosa zone: comments on reliability and global correlations.– cretaceous research, 32, 387–405. ponikarov, v.p. (1966a): the geological map of syria, scale 1:200 000, sheet i–37–xv (tudmor).– explanatory notes, syrian arab republic, ministry of industry. ponikarov, v.p. (1966b): the geological map of syria, scale 1:200 000, sheet i–37–xiv (al­quarentein).– explanatory notes, syrian arab republic, ministry of industry. premoli silva, i. & sliter, w. v. (1994): cretaceous planktonic foraminiferal biostratigraphy and evolutionary trends from the bottacioni section, gubbio, italy.– paleontographica italica, 82, 1–89. premoli silva, i. & sliter, w. v. (1999): cretaceous paleoceanography: evidence from planktonic foraminiferal evolution.– in: geologia croatica 67/2geologia croatica 108 barrera, e.& johnson, c.c. (eds.): the evolution of cretaceous ocean-climatic system.– geological society of america, special paper, 332, 301–328. premoli silva, i., and verga, d., 2004, practical manual of cretaceous planktonic foraminifera.– in: verga, d. & rettori, r. (eds.): international school on planktonic foraminifera, 3rd course: cretaceous. university of perugia and milano, tipografia pontfelecino, perugia, italy, 283 p. pufhal, p.k., grimm, k.a., abed, a.m. & sadaqah, r.m.y. (2003): upper cretaceous (campanian) phosphorites in jordan: implications for the formation of a south tethyan phosphorite giant.– sedimentary geology, 161, 175–205. reiss, z. (1988): assemblages from a senonian high-productivity sea.– revue de paléobiologie, volume spécial 2, 323–332. robaszynski, f. & caron, m. (1995): foraminifers planctoniques du crétacé: commentaire de la zonation europe­méditerrané.– bulletin de la société géologique de france, 6, 681–692. robaszynski, f., caron, m., gonzales, j.m. & wonders, a.h. (eds.) (1984): atlas of late cretaceous globotruncanids.– revue de micropaleontologie, 26, 145–305. robaszynski, f., gonzalez donoso, j.m., linares, d., amédro, f., caron, m., dupuis, c., dhondt, a.v. & gartner, s. (2000): le crétacé supérieur de la région de kalaat senan, tunisie centrale, litho­biostratigraphie intégrée: zones d’ammonites, de foraminifères planctoniques et de nannofossiles du turonien supérieur au maastrichtien.– bulletin des centres de recherche et d’exploration­production d’elf­aquitaine, 22, 359–490. sari, b. (2006): upper cretaceous planktonic foraminiferal biostratigraphy of the bey dağlari autochthon in the korkuteli area, western taurides, turkey.– journal of foraminiferal research, 36, 241–261. sari, b. (2009): planktonic foraminiferal biostratigraphy of the coniacian­maastrichtian sequences of the bey dağlari autochton, western taurides, turkey: thin-section zonation.– cretaceous research, 30, 1103–1132. schneider-mor, a., alsenz, h., aschenazi-polivoda, s., illner, p., abramovich, s., feinstein, s., almogilabin, a., berner, z. & püttmann, w. (2012): paleoceanographic reconstruction of the late creatceous oil shale of the negev, israel: integration of geochemical, and astable isotope records of the organic matter.– palaeogeography, palaeoclimatolology, palaeoecology, 319/320, 46–57. sliter, w.v. (1989): biostratigraphic zonation for cretaceous planktonic foraminifers examined in thin section.– journal of foraminiferal research, 19/1, 1–19. soudry, d., glenn, c.r., nathan, y., segal, i. & vonderhaar, d. (2006): evolution of tethyan phosphogenesis along the northern edges of the arabian–african shield during the cretaceous–eocene as deduced from temporal variations of ca and nd isotopes and rates of p accumulation.– earth­science reviews, 78, 27–57. stanković, d., premec fućek, v., hernitz kučenjak, m., marić đureković, ž., ivak, p., slavković, r. & barbić, z. (2003): biostratigraphy and sedimentology of the campanian and maastrichtian sediments in the palmyra-1 well, palmyrides, syria.– in: vlahović, i. (ed.): abstracts book.– 22nd ias meeting of sedimentology, opatija, croatia, 201. stanković, d., mesić, i.a., ivaniček, z., hernitz kučenjak, m. & premec fućek, v. (2005): upper campanian to maastrichtian foraminiferal assemblages of the palmyra region, syria.– in: velić, i., vlahović, i. & biondić, r. (eds.): proceedings.– third croatian geological congress, opatija, croatia, 127. trappe, j. (2001): a nomenclature system for granular phosphate rocks according to depositional texture.– sedimentary geology, 145, 135–150. widmark, j.g.v. & speijer, r.p. (1997): benthic foraminiferal faunas and trophic regimes at the terminal cretaceous tethyan seafloor.– palaios, 12, 354–371. wood, b. (2011): whole lithospheric folding as a mechanism of basin formation and tectonic implications for gondwana evolution: evidence from the palmyride trough, syria.– expanded abstract presentation at aapg annual convention and exhibition, houston, texas, usa, april 10–13, 2011. manuscript received december 06, 2013 revised manuscript accepted march 08, 2014 available online june17, 2014 pecimotika et al.: planktonic foraminiferal biostratigraphy and paleoecology of upper cretaceous deposits from the palmyride region, syria geologia croatica 109 appendix 1 list of taxa cited in the text and figure explanations, in alphabetical order according to genus planktonic foraminifera abathomphalus intermedius (bolli, 1951) abathomphalus mayaroensis (bolli, 1951) archaeoglobigerina blowi pessagno, 1967 archaeoglobigerina cretacea (d’orbigny, 1840) contusotruncana fornicata (plummer, 1931) contusotruncana plummerae (gandolfi, 1955) dicarinella sp. gansserina gansseri (bolli, 1951) gglobigerinelloides bollii (pessagno, 1967) gobigerinelloides prairiehillensis (pessagno, 1967) globigerinelloides subcarinatus (bröennimann, 1952) globotruncana arca (cushman, 1926) globotruncana bulloides vogler, 1941 globotruncana hilli pessagno, 1967 globotruncana linneiana (d’orbigny, 1839) globotruncanella havanensis (voorwijk, 1937) globotruncanella minuta caron & gonzalez donoso, 1984 globotruncanella petaloidea (gandolfi, 1955) globotruncanella pschadae (keller, 1946) globotruncanita conica (white, 1928) globotruncanita pettersi (gandolfi, 1955) globotruncanita stuarti (de lapparent, 1918) globotruncanita stuartiformis (dalbiez, 1955) guembelitria cretacea cushman, 1933 guembelitria turrita nederbragt, 1990 hendersonites carinatus (cushman, 1938) heterohelix globulosa (ehrenberg, 1840) heterohelix labellosa nederbragt, 1990 heterohelix navarroensis loeblich, 1951 heterohelix moremani (cushman, 1938) heterohelix planata (cushman, 1938) heterohelix punctulata (cushman, 1938) heterohelix reussi (cushman, 1938) heterohelix striata (ehrenberg, 1840) laeviheterohelix dentata (stenestad, 1968) laeviheterohelix glabrans (cushman, 1938) marginotruncana sp. muricohedbergella flandrini (porthault, 1970) muricohedbergeela holmdelensis (olsson, 1964) muricohedbergella mounmouthensis (olsson, 1960) muricohedbergella sp. planoglobulina carseyae (plummer, 1931) planoglobulina acervulinoides (egger, 1899) pseudoguembelina costulata (cushman, 1938) pseudoguembelina excolata (cushman, 1926) pseudoguembelina kempensis esker, 1968 pseudoguembelina palpebra bröennimann & brown, 1953 pseudotextularia elegans (rzehak, 1891) pseudotextularia intermedia de klasz, 1953 pseudotextularia nuttalli (vorwijk, 1937) racemiguembelina fructicosa (egger, 1902) racemiguembelina powelli smith & pessagno, 1973 rugoglobigerina macrocephala bröennimann, 1952 rugoglobigerina hexacamerata bröennimann, 1952 rugoglobigerina rugosa (plummer, 1926) whiteinella balthica douglas & rankin, 1969 whiteinella sp. benthic foraminifera bolivinoides draco (marsson, 1878) bolivinoides miliaris hiltermann & koch, 1950 bolivina incrassata reuss, 1851 bulimina ovulum reuss, 1844 bulimina sp. cibicidoides sp. gaudryina laevigata franke, 1914 gavelinella monterelensis (marie, 1941) gavelinella sp. gyroidinoides globosus hagenow, 1842 gyroidinoides sp. lenticulina rotulata (lamarck, 1804) lenticulina münsteri (roemer, 1839) lenticulina sp. neoflabelina reticulata (reuss, 1851) nodosaria sp. oridorsalis umbonatus (reuss, 1851) oridorsalis sp. praebulimina reussi (morrow, 1934) praebulimina kickapoensis (cole, 1938) serovaina complanata (cushman & stainforth, 1945) spiroplectammina sp. stensioeina pommerana brotzen, 1936 geologia croatica 67/2geologia croatica 110 appendix 2 distribution of late cretaceous genera of planktonic foraminiferal assemblage from al mahr-1 and palmyra-1 wells. depth (m) 180-185 145-150 125-130 90-95 80-85 65-70 40-45 25-30 20-25 biozone i ii iii iv v vi vii viii ix species ricness 14 22 22 24 27 32 41 41 40 abathomphalus intermedius 1 2 1 abathomphalus mayaroensis 1 archaeoglobigerina blowi 15 16 10 6 6 3 3 2 archaeoglobigerina cretacea 12 11 5 2 3 2 2 1 contusotruncana fornicata 17 14 5 6 7 4 2 contusotruncana plummerae 2 6 2 3 dicarinella sp. 9 5 gansserina gansseri 2 1 2 gglobigerinelloides bollii 11 17 27 19 15 8 gobigerinelloides prairiehillensis 11 15 9 13 7 12 9 globigerinelloides subcarinatus 9 8 14 9 9 8 6 7 globotruncana arca 4 4 5 4 9 6 8 14 globotruncana bulloides 3 3 3 4 2 2 1 globotruncana hilli 3 3 2 3 4 2 4 11 globotruncana linneiana 2 2 3 3 4 7 6 globotruncanella havanensis 10 6 5 7 globotruncanella minuta 1 1 3 globotruncanella petaloidea 5 3 3 3 globotruncanella pschadae 3 3 2 globotruncanita conica 1 2 1 globotruncanita pettersi 3 6 3 globotruncanita stuarti 3 4 2 6 2 globotruncanita stuartiformis 7 8 7 6 6 9 7 4 guembelitria cretacea 1 1 hendersonites carinatus 17 34 heterohelix globulosa 38 33 19 14 32 30 29 34 29 heterohelix labellosa 11 14 14 12 14 heterohelix moremani 31 heterohelix navarroensis 8 17 27 23 31 21 heterohelix planata 14 14 32 8 7 6 12 17 heterohelix punctulata 21 33 9 16 9 9 7 11 heterohelix reussi 35 31 18 heterohelix striata 19 35 34 29 32 25 32 27 laeviheterohelix dentata 5 6 10 4 6 laeviheterohelix glabrans 6 4 8 7 7 5 marginotruncana sp. 11 4 muricohedbergella flandrini 18 muricohedbergeela holmdelensis 25 19 9 21 18 8 13 7 12 m. mounmouthensis 17 15 7 4 11 17 muricohedbergella sp. 7 6 7 5 4 planoglobulina carseyae 7 6 5 8 pseudoguembelina costulata 15 31 26 23 26 7 4 pseudoguembelina excolata 6 9 8 7 pseudoguembelina kempensis 3 4 6 pseudoguembelina palpebra 13 7 7 pseudotextularia elegans 11 11 pseudotextularia intermedia 2 1 1 pseudotextularia nuttalli 30 23 33 30 16 21 14 6 4 racemiguembelina fructicosa 1 1 racemiguembelina powelli 2 2 1 rugoglobigerina hexacamerata 4 5 9 10 rugoglobigerina macrocephala 5 15 12 rugoglobigerina rugosa 16 11 17 21 12 24 26 whiteinella balthica 11 whiteinella sp. 9 (%) plankt. foram. 51.22 59.30 64.27 70.21 80.34 85.17 91.24 92.56 93.98 (%) bent. foram. 48.78 40.67 35.72 29.79 19.66 15.05 8.76 7.44 6.02 2016 | 69/2 | 231–243 | 12 figs. | www.geologia-croatica journal of the croatian geological survey and the croatian geological society 1. introduction a “landslide” is the movement of a mass of rock, debris, or earth down a slope under the influence of gravity (cruden & varnes, 1996). here, the terms “landslide”, “mass movement”, and “slope failure” are used as synonyms. mihalić arbanas & arbanas (2014) divided landslide research into five broad cate­ gories: landslide identification and mapping, landslide investigation, landslide monitoring, landslide hazard and risk assessment, and landslide stabilization and remediation measures. the application of advanced technologies for landslide identification, mapping and monitoring in the area of the city of zagreb in croatia began in 2010 in the framework of the bilateral scientific japanese­croatian satreps fy2008 project ‘risk iden tification and land­use planning for disaster mitigation of landslides and floods in croatia’ (mihalić & arbanas, 2012). the implementation of the project’s activities in the continental part of croatia encompassed (i) the identification and mapping of landslides in the southern and south­eastern hills of medvednica mt., which belongs to the city of zagreb; and (ii) monitoring of the deep­seated kostanjek landslide, located in the western part of the hilly area, in an urban part of the city of zagreb. figure 1. depicts the study area for the inventory mapping, with a total area of 180 km2 as indicated by the red line, and the location of the monitored kostanjek landslide, indicated by the red dot. because of its geomorphological and geostructural position, the area of the city of zagreb is located in the western mega­geo­ application of advanced technologies in landslide research in the area of the city of zagreb (croatia, europe) snježana mihalić arbanas, martin krkač and sanja bernat university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, zagreb, croatia; (corresponding author: smihalic@rgn.hr) doi: 10.4154/gc.2016.18 abstract this paper describes the application of advanced technologies for landslide detection, mapping and monitoring in the city of zagreb since 2010. airborne light detection and ranging (lidar) data are used to visually identify landslides in the podsljeme zone over an area of 180 km2 for the purpose of landslide inventory mapping. the total number of landslides in the analyzed area (approx. 1,600 landslides) is estimated based on the average landslide density (9 landslides per square km) from the most reliable geomorphological historical inventory produced in 1979. examples of the visual interpretation of very-high-resolution bare-earth dems (digital elevation model) are given to show the potential of these advanced techniques to identify the landslide contours of the very small, small and moderately small landslides that are characteristic of the study area, which is composed of engineering soils and/or soft rocks (marls). in the framework of the described landslide research, the biggest landslide in the podsljeme zone, the kostanjek landslide (landslide area of 1 km2), was also equipped with an automated near-real time monitoring system that encompassed approximately 40 sensors to monitor landslide movement and landslide causal factors. monitoring of this deep and large landslide during multiple extreme hydro-meteorological events from january 2013 to january 2015 enabled collection of data for the analysis of landslide movement both on and below the surface as well as analysis of the relationship between landslide reactivations and their triggers, i.e., changes in groundwater level and precipitation. the final aim of the described scientific research in terms of landslide mapping and monitoring is its practical application in land-use planning and civil protection systems in the city of zagreb. namely, the conclusions propose reliable and efficient methods for landslide identification and monitoring, which are necessary to provide data and solutions for hazard and risk reduction to local authorities that are managed by the city. morphological region of the european pannonian basin in nw croatia (pavelić et al., 2003). the city covers an area of 640 km2 and includes the urban area (zagreb city) and 69 settlements with approx. 800,000 residents (~18% of the population of croa tia). the urbanized area (220 km2) is located below the forest region of medvednica mt. to the north and extends to the flood plain of the sava river to the south (fig. 1). the climate is continental with a mild maritime influence and a mean annual precipitation (map) of 883.6 mm (bernat et al., 2014). the hills in the northern part of the county (known as the podsljeme zone) were chosen as the study area because 32% of zagreb city belongs to this area. moreover, this area is very attractive as a residential zone with a continuously increasing popu­ lation density and intensifying construction activities with the enlargement of the area of built­up land. one of the oldest prope­ rty damage records from a particular landslide in the podsljeme area dates from 1925 (fijember, 1942). although measures have been taken in the city of zagreb to promote land use, de­ velop ment and construction practices that do not exacerbate the landslide problem, the relative proportion of artificially caused landslides from urbanization of the hilly zone have been continu­ ously increasing over the last 90 years (polak et al., 1971; šikić et al., 1984; cesarec & polak, 1986; jurak et al., 1996, 1998; sokolić et al., 2006). the kostanjek landslide is one of numerous landslides within the borders of the study area but is specific according to its size, as interpreted by ortolan (1996) and stanić & article history: manuscript received october 21, 2015 revised manuscript accepted april 17, 2016 available online june 28, 2016 keywords: landslide identification, landslide mapping, landslide monitoring, kostanjek landslide, podsljeme zone, city of zagreb g eo lo gi a c ro at ic a geologia croatica 69/2232 by airborne lidar (light detection and ranging) in 2011 and 2013 (mihalić et al., 2013). examples from the literature reveal that previous investigators used 5­m resolution dem (van den eeckhaut et al., 2007), 2­m resolution dems (ardizzone et al., 2007), 1.8­m resolution dems (schulz, 2007), or 1­m resolution dems (mckean & roering, 2004; đomlija et al., 2014) for the purpose of landslide inventory mapping. an integrated automated monitoring system of the kostanjek landslide (the kostanjek landslide observatory) was established from 2011 to 2013 in the framework of the japanese­cro­ a tian project (krkač et al., 2013; 2014b). the objective of the monitoring system was to continuously observe the parameters of landslide movement in real­time and monitor the landslide’s causal factors, i.e., processes that trigger landslide reactivations, such as precipitation, groundwater changes and earthquakes (kr kač et al., 2014a). continuous data series that were collect ed by sensor networks enable the analysis of landslide movement and its causes and the analysis of the interrelations between the dynamics of landslide and causal processes. integrated monitoring systems are usually established at landslides for long­term landslide monitoring, which presents high risks for particular societies. examples of landslides that are equipped with integrated monitoring systems include ancona (cotecchia, 2006), corvara (corsini et al., 2005), tessina (petley et al., 2005) and valoria (castagnetti et al., 2013) in italy; gradenbach in austria (brückl et al., 2006); åknes in norway (blikra, 2012); turtle mountain in canada (froese et al., 2012); and grohovo in croatia (arbanas et al., 2012). the following sections briefly describe the study areas (the podsljeme zone and the kostanjek landslide) with summarized overviews of historical data related to landslide events. this section is followed by a short overview of applied advanced technologies, research methods and the main results. after discussing the potential advantages and the current limitations of these new methodologies, the conclusions present a perspective on the future production and use of landslide inventory maps of the entire podsljeme zone area and the future analysis and application of continuous observations of the kostanjek landslide to the prognosis of landslide hazard and risk. 2. landslide inventory mapping 2.1. study area the hilly area in the southern foothills of medvednica mt., which has an area of 180 km2, is highly urbanized and densely populated (belić et al., 2014). the elevations in this area range from 115 to 612 m a.s.l., the prevailing slope angles (59%) are from 6°–24° and 84% of the slopes have slope angles >3°, which are potentially prone to sliding. the dominant types of slope movements are small and shallow landslides that mostly endanger resi­ den tial structures and roads (mihalinec & ortolan, 2008), especially after intensive precipitation events, such as those that are analyzed in bernat et al. (2015) for the period 2010–2015. figure 2 shows typical damaged roads and houses in the winter of 2013 in zagreb. the study area is composed of upper miocene and quaternary sediments (šikić, 1995), as shown in fig. 3. the upper miocene deposits are stratified sands, silts and marls, with moderately to slightly inclined bedding and bedding slope angles that range from 10°–20° (avanić et al., 2003; vrsaljko et al., 2006). the upper parts of the miocene deposits are fine­grained soils, mostly silts. the quaternary deposits are heterogeneous nonveiller (1996): the landslide volume is 32.6 x 106 m3 and the depth of displaced mass is 90 m. the landslide activity over the last 50 years has completely stopped urban planning and development in the approximate 1 km2 area of the kostanjek landslide. construction of new apartment buildings in this residential area is forbidden, and existing houses and structures require repeated remediation. the local authorities from the city of zagreb must find cost­effective solutions for this human and environmental threat. potential hazards in the form of large movements of reactivated landslide can become disastrous because there are approximately 290 endangered buildings on the landslide surface. identifying and mapping landslides in the area of medvednica mt. included landslide inventory mapping based on remote sensing methodologies that were defined in guzzetti et al. (2012). one of the tasks was to find appropriate technologies to determine landslide boundaries of very small to moderately large landslides (primarily <10,000 m2) that are mostly covered by deciduous vegetation and partially masked by urbanization. part of the aforementioned project activities was also the identification and mapping of landslides using visual interpretation of historical stereoscopic aerial photographs. podolszki (2014) estimated the reliability of identified landslides in the study area in zagreb by this conventional technique, which ranged from 32% to 49% depending on the scale of the interpreted photographs. the advanced method that was applied in the study area was an analysis of the surface morphology of very­high­resolution (1­m resolution) digital elevation models (dems) that were captured figure 1. relief map of the city of zagreb with histograms that show the frequency of elevations and slope angles as computed from a 2-m resolution dem for the whole area. the urbanized area, i.e., zagreb city, the border of the croatian-japanese satreps fy2008 project’s pilot area and the location of the kostanjek landslide are also indicated. g eologia c roatica mihalić arbanas et al.: application of advanced technologies in landslide research in the area of the city of zagreb (croatia, europe) 233 mixtures of unfoliated, mostly impermeable clayey­silty soils that are prone to landslides (nonveiller, 1964, 1987; polak, 1978). the geological contact between the miocene sandy­silty soils and the miocene or quaternary clayey­silty soils is highly susceptible to sliding (ortolan et al., 2008). the most frequent aforementioned triggering factors are rainfall (guzzetti et al., 2007; jemec & komac, 2013) and man­made activities. figure 3. presents a precipitation­triggered seasonal landslide inventory with 55 landslides, which were compiled based on information that was collected from the city’s adfigure 2. examples of landslides endangering/damaging houses or public roads in the winter of 2013 in zagreb: (a) lazina landslide; (b) šestinski dol landslide; (c) dubravkin put landslide. figure 3. precipitation-triggered landslide inventory map for the period from 1st january to 7th april 2013. the pie chart shows the relative distribution of the main stratigraphic units; the histogram shows the number of (re)activated landslides per stratigraphic unit. figure 4. precipitation data, mean daily temperature and the number of landslide events per date triggered in the city of zagreb from january to april 2013. g eo lo gi a c ro at ic a geologia croatica 69/2234 ministration, online media and field checking by a professional engineering geologist in november 2013 (bernat et al., 2014). from 1st january to 7th april 2013, the city of zagreb experienced a period of intense rainfall and snowfall with cumulative values over the 97­day period that exceeded 400 mm, which represents 46% of the mean annual precipitation (map). the monthly precipitation during the same period in 2013 was two to three times higher than the average monthly values during the same period from 1862 to 2012 that were recorded at the zagreb­ grič meteorological station. an analysis of the 3­month period from january to march showed that the cumulative precipitation for the analyzed period in 2013 had the highest value (378.7 mm) that was measured over the last 150 years. figure 4. depicts the daily precipitation data (amount of rainfall and snow depth) from january to april 2013 and the number of landslide events per day. from the figure it can be seen that landslides occurred after periods of significant rainfall and snow melt. the largest number of landslides (a total of 41 landslide events) occurred during the period from 30th march until 3rd april 2013. according to an ana­ lysis of the estimated landslide dimensions, 49% of all landslides (re)activated in the season from 1st january to 7th april 2013 were superficial landslides (depth <1 m), which occurred in colluvial deposits and/or artificial deposits (fill) that overlaid engineering soil and soft rocks (bernat et al., 2014). moreover, a total of 28 shallow to moderately shallow landslides occurred, with estimated depth ranges of 3–12 m and maximum landslide areas of 14,000 m2. 2.2. historical landslide data jurak et al. (2008) and mihalić arbanas et al. (2012) described all the historical projects that were implemented in the area of the city of zagreb for landslide mapping, which started in 1967 (magdalenić, 1967). despite the long tradition of landslide mapping in the city, the main problem with the current landslide risk management practices in the city of zagreb is the lack of a suitable landslide inventory and landslide hazard and risk maps (mihalić, 1998; mihalić arbanas et al., 2013), which was defined in van westen et al. (2008) and fell et al. (2008). an analysis of the spatial distribution of landslides performed by podolszki (2014) shows that two geomorphological historical inventories from 1967 (šikić, 1967) and 2007 (miklin et al., 2007) contain inconsistent and unreliable landslide data because of an underestimated number of landslides and overestimated landslide areas. according to a geomorphological historical landslide inventory from 1979 at a scale of 1:10,000 (polak et al., 1979), which encompass 105 km2 of the same hilly zone, the total number of mapped landslides is 931, which implies a landslide frequency of ~9 landslides per square km (šagud, 2015). the total landslide area is 2.8 km2 and the resulting landslide density is 2.7% of the inventory area. the number of landslides is even higher because groups of very small landslides are drawn by single landslide contours, as stated in an accompanying report by polak et al. (1979). according to the same historical data, 90% of the landslides have a landslide area <10,000 m2 (1 ha). podolszki (2014) also performed conventional visual interpretations of stereoscopic aerial photographs from 1964 at a scale of 1:8,000. he also derived a landslide inventory map with an area of 54.14 km2 for 963 landslides, which gives an average landslide density of 17.8 landslides per square km, but reliable identification is estimated for only 50% of all the mapped landslides. stereoscopic analysis of historical aerial photographs from 1964 over a large scale enabled the identification of landslides over a range from 78 m2 to 281,886 m2. the landslide areas of most of the landslides (90.6%) range from 200–3,600 m2. ferić et al. (2012) performed a preliminary visual analysis of the surface morphology with a 1­m resolution bare­earth airborne lidar dem in 2011 in the test area of the podsljeme zone (total area is 24 km2). the result of the analysis was an inventory map with 176 landslides and an average landslide density of 7.3 landslides per square km. most of the mapped landslides are small in size; 60% of them are smaller than 1,000 m2 (0.1 ha). the smallest identified landslide is an unknown landslide with a landslide area of only 48 m2. the largest identified landslide is a known historical landslide: the grmošćica landslide, which has a total length of 300 m and a rupture surface width of 100 m. approximately 80% of identified landslides are in the area under forest (belić et al., 2014). mihalić et al. (2012) analyzed data for approximately 82 landslides from site investigation reports that were prepared from 1968 to 2008. based on available reports, the following information was extracted. the areas of 47 investigated landslides range from 4,000–180,000 m2, and the landslide depths for 15 landslides range from 2–10 m. the data about landslide occurrence time exists only for six landslides in terms of the year when they were activated or reactivated. reactivated landslides are very common. landslide causes are known only for 19 landslides (23% of 82 analyzed landslides), and all are of anthropogenic ori­ gin from construction activities, mostly the loading of slopes or their crests along the upper part of slopes and water leakage from services (water supplies, sewers, storm­water drains). the same historical data show that the investigation period of some landslides is extremely long. for example, the bijenik landslide had been investigated a few times between 1968–2004, before it was finally successfully stabilized. another example of a long investigation period and multiple stabilization works is the česmički landslide, with a period of geotechnical investigation and design from 1969–2004. jukić & sokolić (2013) listed approximately 60 landslides that were (re)activated between january to april 2013 and that require stabilization. an analysis of landslide contours, which are interpreted based on engineering geological field mapping during geotech­ nical investigations, also shows unreliable landslide contours despite the detailed scale of the topographic base maps that were derived from geodetic surveys (mihalić arbanas et al., 2014). a disadvantage of field mapping is a limited ability to accurately determine a landslide boundary in the field because of the reduced visibility of the slope failure (a consequence of the local perspective), the size of the landslide, and the fact that the landslide boundary is often indistinct or fuzzy (most often because of anthropogenic activities), as stated in santangelo et al. (2010). one example of an unsuccessful design of remedial measures because of the incorrect interpretation of landslide boundaries is the črešnjevec landslide, which is briefly described in mihalić et al. (2013). the high uncertainty in the identification of the črešnjevec landslide’s contours in 2001 occurred because of indistinct landslide boundaries, which were interpreted by field mapping approximately 20 years after the landslide occurred and in an environment with significantly modified natural morphology from urbanization between 1982–2001. mihalić et al. (2013) also showed that the historical landslide boundaries of other landslides in zagreb vary significantly in size and shape, not only because of the subjectivity of the investigators, but mainly because of the methodology of landslide mapping. g eologia c roatica mihalić arbanas et al.: application of advanced technologies in landslide research in the area of the city of zagreb (croatia, europe) 235 2.3. airborne laser scanning over the last few years, airborne laser scanning has been made available (jaboyedoff et al., 2010) and has been used to identify and map landslide morphology in areas that are partially or completely covered by dense vegetation (razak et al., 2011). a relatively new remote­sensing tool uses airborne­mounted lasers to obtain digital representations of the topographic surface for areas that range from a few hectares to thousands of square kilometres (shan & toth, 2009). airborne lidar is also known as airborne laser scanning (als) or airborne laser swath mapping (alsm). a laser sensor measures the distance from the instrument and multiple points on the topographic surface. although laser scanning measures the altitudes of all objects that are scanned, post­processing is necessary to create a bare­earth dem to remove the undesired returns from buildings and canopies via filtering the original data (reutebuch et al., 2003). the visual analysis and interpretation of the topographic surface remain the most common and most promising applications of a very­high­ resolution (metric to decimetric) dem from airborne lidar sensors to detect and map landslides over large areas (guzzetti et al., 2012). the required resolution of a bare­earth lidar dem to identify landslides primarily depends on the landslide size. recognizing small cracks and detailed geomorphological features might be one of the most important surface landslide characteri­ stics that can be interpreted from these images, which provides additional information compared to the interpretation of optical images, that is, aerial photos or satellite images. for the lidar data that are used in this study, a test flight (covering 24 km2) took place in april 2011 and a flight over the entire study area (180 km2) was undertaken in december 2013, which corresponds to periods after leaf fall in croatia. the airborne laser scanning system that was used for this research has a measurement rate of 266,000 hz at a 60° angle, with a surface point horizontal accuracy of eight centimetres and vertical accuracy of four centimetres. lidar ground­surface measurements were acquired at an average density of five points per square metre. the raw data were post­processed and a 1­m resolution bare earth dem was interpolated. slope maps, contour line maps and hillshade maps were created from the dem by using standard tools in the arcgis. a contour line map was created with one­ metre intervals, and we chose an altitude angle of 45° for the light source above the horizon and an azimuth angle of 315° for the illumination source for the hillshade map. landslide identification was performed by visual analysis and interpretation of the representation of the topographic surface on all the above­mentioned dem derivative maps. 2.4. results the visual identification of the landslides was based on the recognition of landslide features on three topographic derivative maps: figure 5. composite displays of three different topographic derivative maps of the vrhovec landslide, črešnjevec landslide and lazina landslide; the estimated extents of the landslide bodies have red and black contours. (a) hillshade map of the vrhovec landslide. (b) slope map of the vrhovec landslide. (c) contour map of the vrhovec landslide. (d) hillshade map of the črešnjevec landslide. (e) slope map of the črešnjevec landslide. (f) contour map of the črešnjevec landslide. (g) hillshade map of the lazina landslide. (h) slope map of the lazina landslide. (i) contour map of the lazina landslide. the hillshade maps were generated with an azimuth of 315° and a sun angle of 45° draped over a bare earth dem. the slope maps show high slope angles in warmer colours (red, orange, yellow) and low slope angles in cooler colours (green). the contour maps were generated with 1-m contour spacing. g eo lo gi a c ro at ic a geologia croatica 69/2236 a contour map with a one-metre contour span, a hillshade map and a slope map. the mapped landslides were characterized by visible main landslides features such as main scarps, landslide boundaries and toes, zones of depletion and zones of accumulation. the vrhovec landslide is readily visible on the hillshade map (fig. 5a), slope map (fig. 5b) and contour map (fig. 5c), although it is an approximately eight­year­old landslide and is currently completely covered by dense vegetation. the steepness of the main scarp is considerably higher than the slope itself. in the slope map, these appear as warmer colours (yellow, orange, red), while the scarp in the contour map is identified by a clustering of elevation contours. hummocky topography and the flanks and toe of the landslide are also clearly visible. the vrhovec landslide is a moderately small landslide with an area of 9,923 m2. it is a typical landslide in the investigated area that formed along the geological contact between pleistocene (q1) fine­grained soils and pontian (m7) sandy­silty soils and was caused by human activities, including uncontrolled disposal in the upper part of the slope. figure 5d­f presents the identification results of the previously known črešnjevec landslide, which is characterized by multiple reactivations of the upper part of the slope after unsuccessful remedial measures in 2004. the red and black lines in fig. 5d­f depict the contours of an active slow­moving retrogressive landslide. the reactivated landslide is a small, shallow landslide with an area of 3,181 m2. combining the hillshade, slope and contour maps from the airborne lidar data easily distinguishes only the lower part of the displaced mass, while the main scarp, which has a vertical displacement of approximately 10–30 cm, is not clearly expressed. the identification of the landslide contours in the built­up area of the črešnjevec landslide with airborne lidar data was followed by field checking and mapping because of deformations in the bare earth dem from buildings after post­processing the lidar data. figure 5g­i shows the clearly visible contour of the lazina landslide, which was caused by extreme precipitation on 3rd march 2013. this is also a small and shallow landslide, with an area of 2,842 m2. the lazina landslide had activated in landfill material, and its vegetation cover was completely removed by landslide events. figure 2. shows the main scarp of the lazina landslide photographed after landslide activation in 2013. 3. landslide monitoring 3.1. kostanjek landslide the kostanjek landslide is a reactivated deep­seated large translational landslide that formed in soft rock­hard soil, i.e., pannonian and sarmatian marls. its landslide velocities have been changing over the last 50 years from landslide activation until the present day, ranging from extremely slow to very slow according to the classification of cruden & varnes (1996). following the initial slow movements that caused settlement and fractures of industrial (cement factory) objects in 1963 and damaging numerous private houses within an area of approximately 1 km2 in a very short period, attention shifted to the unstable slopes above the cement factory, which is known as the kostanjek landslide (fig. 6). the initial landslide developed because of a loss in the global stability of gentle to steep slopes above an open pit mine of marls and the cement factory ‘sloboda’. slope movements were caused by mining activities, i.e., undercutting of the slope toe and uncontrolled massive blasting (stanić & nonveiller, 1996). according to the photo interpretation of aerial stereo pairs from 1963 to 1988, the horizontal displacements of the ground surface in the period 1963–1988 ranged from 3 to 6 m (average 12–24 cm per year; ortolan & pleško, 1992), as depicted in fig. 7. the monitoring results of recent movements from 2009– 2012 at 35 stable geodetic points show similar movement directions to historical data (fig. 7). figure 6. kostanjek landslide area as depicted by the red line, which represents the landslide contour. in the background is an orthophoto image from march 2012. devastated slopes of the abandoned open pit mine are expressed by rough relief forms in the middle of the kostanjek landslide. the former cement factory ‘sloboda’ was placed in the plain area in the bottom part of the landslide. figure 7. recent horizontal displacements at the kostanjek landslide area between 2009–2012 (yellow arrows) compared to historical horizontal displacements (white arrows) for 1963–1988. the red line depicts the kostanjek landslide contour. g eologia c roatica mihalić arbanas et al.: application of advanced technologies in landslide research in the area of the city of zagreb (croatia, europe) 237 although numerous surface exploration and visual studies were undertaken between 1966 and 2010 (briefly described in krkač et al., 2013), the rudimentary nature of the monitoring did not provide conclusive evidence regarding the rate and extent of the movement of the kostanjek landslide. a geotechnical report prepared by the croatian civil engineering institute (igh) in 2008 provided only a comprehensive review of all the historical investigations in the area of the kostanjek landslide, with a presentation of the historical landslide model and its geometry, mechanism and contributing factors interpreted by ortolan (1996). the subsurface conditions and contours of the landslide bodies that contribute to the movement must be better defined with respect to an interpreted historical movement of the kos­ tanjek landslide because the specific mechanism of recent movement is not known (krkač et al., 2013). the main objective of the joint research within the framework of the japanese­croatian project was to establish a landslide monitoring system for the purpose of an early warning system (ews). landslide monitoring project activities began in 2011. prior to the completion of the kostanjek landslide monitoring system, the government of the city of zagreb determined in january 2011 that the continuous long­term monitoring of the kos­ tanjek landslide is important for the public safety of the residents. the secondary priority of the monitoring system is to provide an opportunity for the research community to test and develop instrumentation and monitoring technologies and to better understand the mechanics of slow­moving masses. 3.2. monitoring system the sensor network that was installed in the kostanjek landslide area encompasses approximately 40 sensors for the monitoring of landslide movement and landslide causal factors. figure 8. provides the layout of the sensor network that is currently installed at the kostanjek landslide in the framework of the kostanjek landslide observatory. the monitoring system consists of multiple sensor networks for the measurement of (1) external triggers (a rain gauge, a meteorological station and 7 accelerometers), (2) displacement/deformation/activity (15 gnss sensors, 7 extensometers, 4 borehole extensometers and an inclinometer), and (3) hydrological properties (3 pore pressure gauges and 5 water level sensors in boreholes and domestic wells, and 2 water level sensors at outflow weirs). the general design of the monitoring system is described in krkač et al. (2014b). continuous monitoring of external triggers is of crucial importance because of their influence on the reactivation of landslides and the establishment of an ews. rainfall, which is one of the most important landslide triggers (mansour et al., 2010), has been monitored with a 0.5 mm tipping­bucket rain gauge, which is placed in the central part of the kostanjek landslide, since september 2011. the meteorological station was installed in 2014 because of the limitations of the rain gauge in terms of precipitation measurements during snowy periods (krkač et al., 2014a). seven continuously monitoring accelerometers, installed at five locations on the landslide surface and at different depths, record changes according to local ground conditions within the landslide body and in the rock mass below the sliding surface. these accelerometers were installed to record ground shaking (accelerations) in response to earthquakes (trigger) and in response to landslide movements (activity). slope movement monitoring provides data about the actual state of landslide activity through observations of slope movement parameters (displacement, velocity and acceleration) on the surface of a landslide. this process enables the recognition and quantification of reactivation phases and definition of threshold values approaching critical acceleration and, ideally, enables the forecasting of the catastrophic sliding phases (baroň et al., 2012). high­resolution temporal and spatial data at the kostanjek landslide were obtained from surface movement monitoring by the gnss (global navigation satellite system) sensor network (system of satellites and earth stations for precise positioning on earth’s surface) and a large number of wire extensometers (sensors that measure the relative displacement between two points). fifteen densely distributed gnss sensors (double­frequency netr9 ti­2 gnss reference station with zephyr geodetic 2 gnss antenna, trimble) provide highly accurate data, which depends on the post­processing time. for example, the temporal resolution of the data can be every second in the real­time kinematic mode. these near­real­time and real­time movement data satisfy the requirements for failure prediction by using, for example, fukuzono’s (1985) method. seven wire extensometers (netlg­501e, osasi technos inc.) provide data every hour. unreliability in the extensometer data can be caused by the influence of meteorological conditions, which must be considered during interpretation of the landslide movement parameters. subsurface movement at the kostanjek landslide, which was measured by inclinometer, provided reliable data regarding the sliding surface depth, mechanical behaviour and displacement from april 2012 to february 2013. after this period, the inclinometer casing became impassable because of a large displacement along the sliding surface. although the inclinometer data are of good quality, both the temporal (a few measurements in one year) and spatial resolution (only one borehole with inclinometer casing in the central part of the landslide) are very poor. higher spatial resolution is necessary to confirm the existing prognostic landslide model. monitoring the subsurface movement at the central location of the landslide was improved by installing four vertical wire extensometers at different depths in the borehole near the existing inclinometer casing. these devices will provide continuous displacement monitoring data even for larger displacements. the hydrological conditions have the most significant influence on landslide behaviour, e.g., changes in the pore water pressure and groundwater levels. continuous observations of pore water pressure and groundwater level at the kostanjek landslide provide good temporal data (every hour). the sensors were installed at a few locations in different parts of the landslide body, as depicted in fig. 8. three piezometers with pore pressure gauges were installed in the central part of the landslide body, one is in the zone of the sliding surface and two are in the landslide mass. two water level gauges were installed in the central part of the landslide, while three water level gauges were installed on the western, northwestern and northern landslide boundaries. although the water level sensors that were installed near the landslide boundary do not actually measure the water level in the sliding surface area, the data show good correlation with landslide movements. 3.3. monitoring results landslide movement sensors recorded multiple reactivations of the kostanjek landslide from external triggers in 2013 and 2014. krkač (2015) identified five periods of faster movement (landslide reactivations) based on analyses of observations from the gnss network. the cumulative horizontal displacements that were recorded by the gnss sensor network over these two years are shown in fig. 8. the maximal displacement of 426 mm was g eo lo gi a c ro at ic a geologia croatica 69/2238 measured in the lower central part of the landslide (gnss 9), while the minimal displacement of 38 mm (gnss 15) was measured along the southwestern landslide boundary. the amount of displacement in the central part of the landslide and in the foot part is approximately two to four times higher than the displacement near the landslide’s boundaries (fig. 8). figure 9. shows the evolution of the 2d surface displacement that was registered by four gnss sensors. during the monito ring period, the first and most intensive period of faster movement occurred from 22nd january to 24th may 2013 (fig. 9). during this period, the horizontal displacements ranged from 36.9 mm at the northwestern landslide boundary (gnss 13) to 168 mm in figure 8. locations of the monitoring sensors at the kostanjek landslide and the cumulative horizontal displacements that were recorded by the gnss sensor network from january 2013 to january 2015 (according to krkač, 2015). the red line depicts the kostanjek landslide contour. figure 9. cumulative horizontal displacements versus time for gnss 2 and 13 (near the landslide boundary), gnss 8 and gnss 9 (in the central part of the landslide). the gray area indicates the first period of faster movement. g eologia c roatica mihalić arbanas et al.: application of advanced technologies in landslide research in the area of the city of zagreb (croatia, europe) 239 the lower central part of the landslide (gnss 9). the maximum recorded velocities were from 1.8 mm/day (gnss 2, located at the northern boundary) to 4.8 mm/day (gnss 9). the maximum rates of displacement, with velocities of 2 to 4.8 mm/day, occurred during the first week of april. the first period of faster movement was caused by a total precipitation amount of 455.2 mm from december 2012 to march 2013. during the monitoring period, three of the seven installed extensometers showed significant displacement, namely, the long­span extensometer (ex 3) that crosses the main scarp, the short­span extensometer (ex 4) that crosses the fracture in the eastern part of the landslide and the short-span extensometer (ex 1) that crosses the sliding surface in the abandoned tunnel (figs. 8 & 10). the maximum recorded relative displacement was 142 mm, which was measured by the extensometer that crosses the main scarp (ex 3). during the first period of faster movement, all three extensometers displayed extension, but the amount of measured relative displacement varied from 40 mm along the fracture on the eastern side of the landslide body to 72.5 mm on the main scarp and 97 mm in the central part, where the sliding surface intersects the tunnel (fig. 10). an inclinometer tube was installed in march 2012 in a 100 m­deep borehole in the central part of the landslide. the inclinometric profile, which was obtained based on three measurements, indicates that the failure occurred in a thin basal shear zone at a depth of 62.5 m (fig. 11). deformation above 62.5 m can be considered negligible in terms of landslide mechanisms. deformation at depths of 15 to 30 m is probably a consequence of borehole casing deformation from improper inclinometer tube installation and voids between the inclinometer casing and the in­situ ground (krkač et al., 2014a). 3.4. preliminary application of monitoring results gradiški et al. (2013) presented slope stability analyses of the kostanjek landslide (fig. 12) with the ls­rapid software (integrated landslide simulation model) (sassa & he, 2013). an existing landslide model from ortolan (1996) was modified based on the monitoring results by creating an ellipsoidal sliding figure 10. relative displacements versus time for ex 1 (extensometer below ground installed across the sliding surface in the abandoned tunnel), ex 3 (extensometer at the surface installed across the main scarp) and ex 4 (extensometer at the surface installed across a fracture in the eastern part of the kostanjek landslide). the gray area indicates the first period of faster movement. figure 11. cumulative inclinometer displacements for the a and b axes (according to krkač et al., 2014a). g eo lo gi a c ro at ic a geologia croatica 69/2240 surface with a maximum depth of 65 m in the central part of the landslide body (according to the maximum displacements). the parameters that were used for these analyses were determined from drained test samples in a ring shear apparatus, which was performed in the framework of the japanese­croatian project. analyses were performed for the assumed pore pressure on the sliding surface. according to the results of the analyses, the most unstable part of the landslide is the central part of the landslide body, the slopes of the abandoned open marl pit. in the analyses, the movements started in the central part of the landslide body, and the failure area expanded around the initial failure zone. at the end of the simulation, the area of the entire landslide mass corresponded to the landslide contour from the historical landslide model according to ortolan (1996). this is also in accordance with the new surface deformations (cracks, bulging, and subsi­ dence) that developed during very recent landslide movement in 2013–2014, as shown by the arrows in fig. 8. more reliable analyses require defining the following factors more precisely: the sliding surface, with more correct positions along particular landslide cross sections; the groundwater table surface, which needs to be derived based on measured groundwater levels; and soil parameters, determined from additional undrained ring shear tests. additional subsurface investigations, necessary to interpret more reliably the sliding surface depths, include drilling of boreholes with depths of 10–95 m, followed by soil/rock determination and inclinometer monitoring. the groundwater table surface must be monitored and measured continuously by at least seven piezometers. 4. discussion this paper describes two groups of methodologies that were applied in the framework of the scientific japanese­croatian satreps fy2008 project (2009–2014) in the hilly area of medvednica mt. in the city of zagreb. both the methodology for landslide identification and mapping and the methodology for landslide monitoring are based on new advanced technologies, which enable the development of appropriate methods for the specific engineering geological conditions in the study area of the podsljeme zone. the general objective of the research was to discover methods to efficiently gather more reliable data regarding existing landslides in both detailed and large scales to satisfy the requirements of land use planning, construction and civil protection within the city. this discussion presents the main advantages and disadvantages of the tested methodologies. within the framework of the study that was described in the paper, we verified a visual analysis of airborne lidar dems with 1­m resolution for landslide identification and mapping. data captured at the end of 2013 enabled visual mapping of all the landslides that (re)activated during the extremely wet season in 2013, along with old landslides, with sizes greater than 50 m2. no limi­ tation exists in terms of the maximum landslide area. the vrhovec and lazina landslides illustrate the main advantages of landslide identification from very­high­resolution bare­earth dems: (i) readily visible landslide features (main scarp, landslide flanks and toes, the morphologies of depletion and accumulation zones) of the 8­year­old landslide that are completely covered by dense vegetation (scrub and forest) and new landslides that are partially covered by vegetation; and (ii) the ability to accurately determine a landslide boundary from completely visible slope failures (a consequence of the aerial perspective) and to determine the size of a landslide. the črešnjevec landslide illustrates the main disadvantage of landslide identification from very­high­resolution bare­earth dems. built­up zones prevent the identification of landslide features because of deformation that remains in the bare­earth dem after post­processing. consequently, the landslide boundary is often indistinct or fuzzy, as in the upper part of the črešnjevec landslides, where the main scarp and landslide flanks around the depletion zone in the landslide body were identified exclusively with field checking. in the podsljeme zone, the limitations of visual interpretations of dem­derivative maps in built­up areas can easily be overcome by field checking because only approximately 20% of the area is urbanized. these areas are easy to approach because of a dense network of roads, which will enable map validation and the verification of specific problematic areas. moreover, field checking areas of less than 15% is usual during landslide inventory mapping (galli et al., 2008). the kostanjek landslide presents a risk for approximately 290 buildings (mostly residential houses) in an area of one square kilo­ metre in the urban part of the city of zagreb. the automated continuous monitoring sensor network provided good quality data for the establishment of relationships between landslide movement parameters and the triggering causal factor parameters to predict faster movements, accelerated movement and/or large displacements. the monitoring sensors at the kostanjek landslide recorded multiple landslide reactivations from external triggers, such as during the winter of 2012/2013 and the spring of 2013. the advantages of the monitoring system at the kostanjek landslide observatory are as follows: (i) using multiple sensors for the purpose of movement monitoring at the same position in the central part of the landslide (consisting of a gnss station, extensometer, inclinometer and vertical extensometer), guarantees redundant measurements and can prevent data loss if one instrument fails; figure 12. slope stability analyses of the kostanjek landslide for ru=0.3, ru=0.5, and ru=0.8 (according to gradiški et al., 2013). g eologia c roatica mihalić arbanas et al.: application of advanced technologies in landslide research in the area of the city of zagreb (croatia, europe) 241 (ii) using the same position for different types of movement moni­ toring sensors in the central part of a landslide (consisting of the aforementioned sensors) also enables the spatial correlation of measurement data on the landslide surface and within the landslide profile; and (iii) using different geodetic and geotechnical sensors in combination with hydrological monitoring equipment (measuring precipitation and pore pressures in the landslide profile) allows a reconstruction of the relationships between rainfall, groundwater level, and consequent landslide behaviour as a basis for establishing an early warning system. however, the main disadvantages of the kostanjek monitoring system are related to missing sensors in all parts of this large and deep­seated landslide. additional inclinometers in different parts of the landslide are necessary to provide reliable data regarding the geometry of the entire sliding surface. additional piezometers are also necessary in different parts of the landslide to provide measurements of pore water pressure to better understand the landslide behaviour and correlation with causal factors. the greater displacements in the central part of the landslide compared to the displacement along the landslide boundaries implies the necessity of identifying zones within the landslide body with different hazard and risk levels. this can be achieved by combining the described series of monitoring data from the kostanjek landslide with other advanced remote sensing technologies. tofani et al. (2013) and komac et al. (2015) integrated persistent scatterer interferometry (psi) data with in situ monitoring instrumentation and showed that the joint use of satellite and ground­based data with the geological interpretation of a landslide allows a better understanding of landslide geometry and kinematics. the integration of ground­based moni­ toring data and psi data are potentially providing sound results for the characterization of the slow­moving kostanjek landslide. defining the state of activity of numerous very small to mode­ rately large landslides (primarily <10,000 m2), along with the large kostanjek landslide, would be useful when dealing with landslide identification, mapping, monitoring and hazard analysis in the city of zagreb. in particular, satellite sar (synthetic aperture radar) interferometry (tofani et al., 2013) has proven to be a sound tool to assess changes on the earth’s surface for landslide mapping and monitoring purposes. psi represents a powerful tool to measure landslide displacement because it offers a synoptic view that can be repeated at different time intervals and at various scales. 5. conclusions this study described landslides in the hilly area of the medvednica mt. in the city of zagreb as the main geological hazard, as proven in 2013 by the activation of new or reactivation of old landslides when approximately 60 slope movements endangered residential houses and roads, including the large, deep­seated 50­year­old kostanjek landslide. the overview of existing information and knowledge regarding landslides in the city of zagreb proves the need for the application of new advanced technologies, which will enable the fast and efficient gathering of data regarding landslide locations, exact landslide contours, the state of activity and the time of (re)activation. the landslide inventory map of the large hilly area in the city of zagreb (180 km2) can be derived from the visual interpretation of a very­high­resolution bare­earth dem that was captured by airborne lidar sensors. the 1­m resolution enables the identification of detailed geomorphological features and the precise interpretation of contours of very small to moderately small landslides (<10,000 km2), which are typical for the study area. by providing insight into landslides in highly vegetated areas, which are most often in the studied podsljeme zone (~70% covered by forest), this advanced method is proposed as the most appropriate for landslide identification compared to the interpretation of optical images, that is, aerial photos or satellite images. prospective uses of the visual interpretation of very­high­ resolution bare­earth dems from airborne lidar sensors in the podsljeme zone include landslide inventory mapping to produce reliable inventories of all landslide phenomena that are or have been active in an area, independent of its size or time of activation. reliable landslide inventory maps will enable further analy­ sis of existing landslides (in the form of landslide distribution maps), or the prognosis of landslide hazards (in the form of landslide susceptibility and hazard maps), which are necessary for the strategic planning of landslide management within the entire podsljeme zone. derived information regarding landslides will be used by the city administration to work with land use planning, construction and civil protection. in addition to the precise identification of landslide contours, the most dangerous landslides, which present high societal risks, should be continuously monitored by sensors for their movements and triggers (precipitation, groundwater level, earthquakes). analysis of continuous series of data from observations of the kostanjek landslide showed five periods of reactivation in 2013 and 2014 that were characterized by movement parameters (displacement, distance, velocity and acceleration) that enable the temporal and spatial interpretation of landslide reactivations. temporal information regarding faster sliding enabled correlations with triggering factors, i.e., the determination of particular periods of groundwater changes and periods of higher precipitation and the interpretation of the hydrological conditions that led to sliding. spatial information regarding the distribution of slope movement along displaced masses (on the surface and in the underground) of the kostanjek landslide enabled more reliable mode­ ling of future landslide movements in the entire landslide area. the perspective on the future analysis of continuous observations of the kostanjek landslide and its application to the prognosis of landslide hazard and risk includes the development of an early warning system in the area of the kostanjek landslide. reliable data series that were gathered by the monitoring sensor networks of the kostanjek landslide observatory include source data for modeling the relationships between landslide movement parameters and landslide causal factor parameters. empirical models will define the threshold values of landslide movement parameters and the triggers of sliding, which are necessary for the prognosis of possible movements within the kostanjek landslide, i.e., the evalua­ tion of landslide hazard. moreover, the same models will provide source data for the simulation of different scenarios through numerical modeling of landslide movements and the production of landslide hazard and risk maps for the kostanjek landslide. acknowledgment the results presented herein have been obtained with financial support from jst/jica’s satrep fy2008 program (science and technology research partnership for sustainable development). co­financing was ensured from the ministry of science, education and sports of the republic of croatia, the city office for physical planning, construction of the city, utility services and transport, city of zagreb and the emergency management office of the city of zagreb. these supports are gratefully acknow­ ledged. the authors would like to express our great appreciation to the company trimble and geomatika­smolčak ltd. for spong eo lo gi a c ro at ic a geologia croatica 69/2242 soring the kostanjek landslide observatory and to the city office for the strategic planning and development of the city, city of zagreb and the meteorological and hydrological service of the republic of croatia (dhmz) for allowing us to use digital data from their archives. the authors are grateful to anonymous reviewers for their invaluable advices. references arbanas, ž., sassa, k., marui, h. & mihalić, s. (2012): comprehensive monitoring system on the grohovo landslide, croatia.– in: eberhardt, e., froese, c., turner, k. & leroueil, s. (eds.): landslides and engineered slopes: protecting society through improved understanding, proceedings of the 11th international & 2nd north american symposium on landslides, banff, canada, june 3–8, 2012. taylor and francis group, london, 1441–1447. ardizzone, f., cardinali, m., galli, m., guzzetti, f. & reichenbach, p. (2007): identification and mapping of recent rainfall­induced landslides using elevation data collected by airborne lidar.– natural hazards and earth system sciences, 7/6, 637–650. avanić, r., kovačić, m., pavelić, d., miknić, m., vrsaljko, d., bakrač, k. & galović, i. (2003): the middle and upper miocene facies of mt. medvednica (northern croatia).– in: vlahović, i & tišljar, j. (eds.).: evolution of depositional environments from the palaeozoic to the quaternary in the karst dinarides and the pannonian basin, 22nd ias meeting of sedimentology, opatija, croatia, sept. 17–19, 2003. institute of geology, zagreb, 167–172. baroň, i., supper, r. & ottowitz, d. (2012): report on evaluation of mass movement indicators, safeland deliverable d4.6.– geological survey of austria, vienna, 382 p. belić, n., mihalić arbanas, s., šiško, d. & gajski, d. (2014): derivation of historical land cover map based on digital orthophoto images of the zagreb area.– in: mihalić arbanas, s. & arbanas, ž. (eds.): landslide and flood hazard assessment, proceedings of the 1st regional symposium on landslides in theadriatic­balkan region, zagreb, croatia, march 6–9, 2013. croatian landslide group, zagreb, 63–66. bernat, s., mihalić arbanas, s. & krkač, m. (2014): inventory of precipitation triggered landslides in the winter of 2013 in zagreb (croatia, europe).– in: sassa, k., canuti, p. & yin, y. (eds.): proceedings of the 3rd world landslide forum, landslide science for a safer geoenvironment, volume 2: methods of landslide studies, beijing, china, june 2–6, 2014. springer, cham, 829–836. bernat, s., mihalić arbanas, s. & krkač, m. (2015): catalog of precipitation events that triggered landslides in northwestern croatia.– in: proceedings of the 2nd regional symposium on landslides in the adriatic­balkan region, beo­ grad, serbia, march 6–9, 2013. in press. blikra, l.s. (2012): the åknes rockslide, norway.– in: clague, j.j., stead, d. (eds.): landslides – types, mechanisms and modeling. cambridge university press, cambridge, 323–334. brückl, e., brunner, f.k. & kraus, k. (2006): kinematics of a deep­seated landslide derived from photogrammetric, gps and geophysical data.– engineering geology, 88, 149–159. castagnetti, c., bertacchini, e., corsini, a. & capra, a. (2013): multi­ sensors integrated system for landslide monitoring: critical issues in system setup and data management.– european journal of remote sensing, 46, 104–124. cesarec, m. & polak, k. (1986): klizišta na području grada zagreba [landslides in the area of the zagreb city – in croatian].– in: proceedings of the xvi symp. yssmfe, aranđelovac, yugoslavia, nov. 5–8, 1986. 169–184. corsini, a., pasuto, a., soldati m. & zannoni, a. (2005): field monitoring of the corvara landslide (dolomites, italy) and its relevance for hazard assessment.– geomorphology, 66, 149–165. cotecchia, v. (2006): the second hans cloos lecture. experience drawn from the great ancona landslide of 1982.– bulletin of engineering geology and the environment, 65, 1–41. cruden, d.m. & varnes, d.j. (1996): landslide types and processes.– in: tur­ ner, a.k. & schuster, r.l. (eds.): landslides: investigation and mitigation, transportation. research board special report 247, national research council, washington, d.c., 36–75. đomlija, p., bernat, s., mihalić arbanas, s., & benac, č. (2014): landslide inventory in the area of dubračina river basin (croatia).– in: sassa, k., canuti, p. & yin, y. (eds.): proceedings of the 3rd world landslide forum, landslide science for a safer geoenvironment, volume 2: methods of landslide studies, beijing, china, june 2–6, 2014. springer, cham, 837–842. fell, r., corominas, j., bonnard, c., cascini, l., leroi, e. & savage w.z. (2008): guidelines for landslide susceptibility, hazard and risk zoning for land use planning.– engineering geology, 102, 85–98. ferić, p., mihalić, s. & krkač, m. (2012): visual mapping of landslides from lidar imagery, zagreb, croatia.– in: ožanić, n., arbanas, ž., mihalić, s., marui, h. & dragičević, n. (eds.): proceedings of the 2nd workshop of the croatian­japanese satreps fy2008 project, rijeka, croatia, dec. 15–17, 2011. university of rijeka, rijeka, 130–133. fijember, m. (1942): klizanje tla zagrebačkih obronaka [landslides in the hilly area of the city of zagreb – in croatian].– tehnički vjesnik, 59, 20–29. froese, c.r., charrière, m., humair, f., jaboyedoff, m. & pedrazzini, a. (2012): characterization and management of rockslide hazard at turtle mountain, alberta, canada.– in: clague, j.j. & stead, d. (eds.): landslides – types, mechanisms and modeling. cambridge university press, cambridge, 310–322. fukuzono, t. (1985): a new method for predicting the failure time of a slope.– in: proceedings of 4th international conference and field workshop on landslides. japan landslide society, tokyo, 145–150. gall, m., ardizzone, f., cardinali, m., guzzetti, f. & reichenbach, p. (2008): comparing landslide inventory maps.– geomorphology, 94, 268–289. gradiški, k., krkač, m., mihalić arbanas, s. & bernat, s. (2013): slope stability analyses of the kostanjek landslide for extreme rainfalls in the winter of 2013.– in: vlastelica, g., andrić, i. & salvezani, d. (eds.): book of abstracts, 4th workshop of the japanese­croatian project on risk identification and land­use planning for disaster mitigation of landslides and floods in croatia, split, croatia, dec. 12–14, 2010. university of split, faculty of civil engineering, architecture and geodesy, 15–16. guzzetti, f., mondini, a.c., cardinali, m., fiorucci, f., santangelo, m. & chang. k.t. (2012): landslide inventory maps: new tools for an old problem.– earth­science reviews, 112, 42–66. guzzetti, f., peruccacci, s., rossi, m. & stark, c. p. (2007): rainfall thresholds for the initiation of landslides in central and southern europe.– meteorology and atmospheric physics, 98, 239–267. jaboyedoff, m., oppikofer, t., abellan, a., derron, m.h., loye, a., metzger, r. & pedrazzini, a. (2010): use of lidar in landslide investigations: a review.– natural hazards, 61/1, 5–28. jemec, m. & komac, m. (2013): rainfall patterns for shallow landsliding in perialpine slovenia.– natural hazards, 67/3, 1011–1023. jukić, m. & sokolić, ž. (2013): tehničko promatranje sustava za prihvat i odvodnju voda kao jedan od osnovnih elemenata u strategiji zaštite od klizišta [technical survey of water recharge and drainage as one of the basic element in strategy of slope remediation – in croatian].– in: matešić, l. & sokolić, i. (eds.): 6. savjetovanje hrvatskog geotehničkog društva, sanacija, tehničko praćenje i održavanje u geotehnci, zadar, peruća, croatia, oct. 17–19, 2013. hrvatsko geotehničko društvo, 173–179. jurak, v., matković, i., miklin, ž. & mihalić, s. (1996): data analysis of the landslides in the republic of croatia: present state and perspectives.– in: senneset, k. (ed.): proceedings of the 7th international symposium on landslides, trondheim, norway, june 17–21, 1996. crc press, taylor & francis, london, 1923–1928. jurak, v., ortolan, ž., ivšić, t., herak, m., šumanovac, f., vukelić, i. & jukić, m. (2008): geotehničko i seizmičko mikrozoniranje grada zagreba – pokušaji i ostvarenje. [geotechnical and seismic microzonation of zagreb: attempts and realization – in croatian].– in: radić, j. (ed.): zbornik radova konferencije razvitak zagreba, zagreb, croatia, feb. 1–2, 2008. secon hdgk, zagreb, 99–108. komac, m., holley, r., mahapatra, p., van der marel, h. & bavec, m. (2015): coupling of gps/gnss and radar interferometric data for a 3d surface displacement monitoring of landslides.– landslides, 12/2, 241–257. krkač, m. (2015): fenomenološki model gibanja klizišta kostanjek na osnovi praćenja parametara klizanja [a phenomenological model of the kostanjek landslide movement based on the landslide monitoring parameters – in croatian].– unpubl. phd thesis, faculty of mining, geology and petroleum engineering, university of zagreb, 210 p. krkač, m., mihalić, s., ferić, p., podolszki, l., toševski, a. & arbanas, ž. (2013): japanese­croatian project: preliminary investigations of the kostanjek landslide.– in: margttini, c., canuti, p. & sassa, k. (eds.): proceedings of 2nd world landslide forum, ‘landslide science and practice’, vol. 6, rome, italy, oct. 3–9, 2011. springer, germany, 385–390. krkač, m., mihalić arbanas, s., arbanas, ž., bernat, s. & špehar, k. (2014a): the kostanjek landslide in the city of zagreb: forecasting and protective monitoring.– in: lollino, g., manconi, a., guzzetti, f., culshaw, m., bobrowsky, p. & luino, f. (eds.): proceedings of the xii iaeg congress, engineering geology for society and territory, vol. 5, urban geology, sustainable planning and landscape exploitation, torino, italy, sept. 15–19, 2014. springer, heidelberg, 715–719. krkač, m., mihalić arbanas, s., nagai, o. & arbanas, ž. (2014b): the kostanjek landslide – monitoring system development and sensor network.– in: mihalić arbanas, s. & arbanas, ž. (eds.): landslide and flood hazard assessment, proceedings of the 1st regional symposium on landslides in the adriatic­balkan region, zagreb, croatia, march 6–9, 2013. croatian landslide group, zagreb, 2014, 27–32. g eologia c roatica mihalić arbanas et al.: application of advanced technologies in landslide research in the area of the city of zagreb (croatia, europe) 243 magdalenić, a. (1967): klizišta u sjeverozapadnoj hrvatskoj [landslides in the north-west croatia – in croatian].– in: proceedings in road design and construction in sfr yugoslavia, 95–101. mansour, m.f., morgenstern, n.r. & martin, d. (2010): expected damage from displacement of slow­moving slides.– landslides, 8, 117–131. mckean, j. & roering, j. (2004): objective landslide detection and surface morphology mapping using high­resolution airborne laser altimetry.– geomorphology, 57/3–4, 331–351. mihalić, s. (1998): recommendations for landslide hazard and risk mapping in croatia.– geologia croatica, 51/2, 195–204. mihalić, s. & arbanas, ž. (2012): the croatian­japanese joint research project on landslides: activities and public benefits.– in: sassa, k., rouhban, b., briceño, s., mcsaveney, m., he, b. (eds.): landslides: global risk prepa­ redness. springer, heidelberg, 333–349. mihalić, s., bernat, s., hamasaki, e. & gerber, n. (2012): historical landslides in the city of zagreb: landslide distribution analysis and 3d modeling of typical landslides in adcalc3d.– in: ožanić, n., arbanas, ž., mihalić, s., marui, h. & dragičević, n. (eds.): proceedings of the 2nd workshop of the croatian­japanese satreps fy2008 project, rijeka, croatia, dec. 15–17, 2011. university of rijeka, rijeka, 2012, 122–125. mihalić, s., marui, h., nagai, o., yagi, h., miyagi, t. (2013): landslide inventory in the area of zagreb city: effectiveness of using lidar dem.– in:margttini, c., canuti, p. & sassa, k. (eds.): proceedings of 2nd world landslide forum, ‘landslide science and practice’, vol. 1, rome, italy, oct. 3–9, 2011. springer­verlag, germany, 155–162. mihalić arbanas, s. & arbanas, ž. (2014): landslides: a guide to researching landslide phenomena and processes.– in: gaurina međimurec, n. (ed.): handbook of research on advancements in environmental engineering. engineering science reference, hershey pa, usa, 474–508. mihalić arbanas, s., arbanas, ž., bernat, s., krkač, m., kalinić, p., martinović, k., fabris, n., sajko, j. & antolović, a., (2013): upravljanje kriznim situacijama uslijed pokretanja klizišta [crisis management in case of landslide activations – in croatian].– in: perinić, j. (ed.): zbornik radova v. konferencije hrvatske platforme za smanjenje rizika od katastrofa, valbadon, croatia, oct. 17, 2013. državna uprava za zaštitu i spašavanje, zagreb, 151–164. mihalić arbanas, s., bernat, s., fabijanović, s. & arbanas, ž. (2014): the analysis of historical landslide information from the area of the city of zagreb and primorsko­goranska county.– in: mihalić arbanas, s. & arbanas, ž. (eds.): landslide and flood hazard assessment, proceedings of the 1st regional symposium on landslides in the adriatic­balkan region, zagreb, croatia, march 6–9, 2013. croatian landslide group, zagreb, 91–96. mihalić arbanas, s., krkač, m., bernat, s. & arbanas, ž. (2012): use of existing data in the city of zagreb (croatia, europe) for the purpose of geo­ planning.– in: zhou, y., cai, j. & sterling, r. (eds.): proceedings ‘advances in underground space development’, singapore, november 7–9, 2012. research publishing, 465–477. mihalinec, z. & ortolan, ž. (2008): landslide ‘granice’ in zagreb (croatia).– in: chen, z., zhang, j.­m., ho, k., wu, f.­q. & li, z.­k. (eds.): proceedings of the 10th international symposium on landslides and engineered slopes, xi’an, china, 30 june­4 july, 2008. crc press, 1587–1593. miklin, ž., mlinar, ž., brkić, ž., hećimović, i. & dolić, m. (2007): detaljna inženjerskogeološka karta podsljemenske urbanizirane zone u mjerilu 1:5.000 (digk­faza i) [detailed engineering geological map of the podsljeme urbanized zone in a scale of 1:5,000 (digk-phase i) – in croatian].– croatian geological survey, zagreb, croatia. nonveiller, e. (1964): klizište u krutoj raspucaloj diluvijalnoj glini na prekrižju u zagrebu [landslide in stiff fractured diluvial clay at the prekrižje in zagreb – in croatian].– građevinar, 2, 58–64. nonveiller, e. (1987): kliženje i stabilizacija kosina [sliding and slope stabilization – in croatian].– školska knjiga, zagreb, croatia, 204 p. ortolan, ž. (1996): formiranje prostornog inženjerskogeološkog modela dubokog klizišta s više kliznih ploha (na primjeru klizišta podsused) [development of 3d engineering geological model of deep landslide with multiple sliding surffaces (example of the podsused landslide) – in croatian].– unpubl. phd thesis, fa­ culty of mining, geology and petroleum engineering, university of zagreb, 236 p. ortolan, ž. & pleško, j. (1992): repeated photogrammetric measurements at shaping geotechnical models of multi­layer.– rudarsko­geološko­naftni zbornik, 4, 51–58. ortolan, ž., jurak, v., ivšić, t., herak, m. & vukelić, i. (2008): geotehničke okolnosti – rubni uvjet održivog razvitka “podsljemenske urbanizirane zone [geotechnical circumstances – boundary conditions for sustainable development of the ‘podsljeme foothills urbanized zone’ – in croatian].– in: radić, j. (ed.): proceedings of the conference ‘development of the zagreb’, zagreb, croatia, feb. 1­2, 2008. secon hdgk, zagreb, 273–284. pavelić, d., avanić, r., kovačić, m., vrsaljko, d. & miknić, m. (2003): an outline of the evolution of the croatian part of the pannonian basin system.– in: vlahović, i. & tišljar, j. (eds.): 22nd ias meeting of sedimentology, opatija 2003 − field trip guidebook. institute of geology, zagreb, 155–161. petley, d.n., mantovani, f., bulmer, m.n. & zannoni, a. (2005): the use of surface monitoring data for the interpretation of landslide movement patterns.– geomorphology, 66/1–4, 133–147. podolszki, l. (2014): stereoskopska analiza klizišta i relativne opasnosti od kliza nja na južnim obroncima medvednice [stereoscopic analysis of landslides and landslide susceptibility on the southern slopes of medvednica mt. – in croatian].– unpbl. phd thesis, faculty of mining, geology and petroleum engineering, university of zagreb, 322 p. polak, k. (1978): neke značajke kvartarnih sedimenata istraživanih na primjeru klizišta jelenovac kraj zagreba [some of the properties of the quaternary deposits – case study of the jelenovac landslide near zagreb – in croatian]. – geološki vjesnik, 30/1, 151–165. polak, k., klemar, m., nejkova, m., radošević, n., stepan, z., miroslav, m. & križanić, z. (1979): litološka obrada i kategorizacija terena prema stabilnosti tla obronaka medvednice na području grada zagreba [lithological characterization and slope stability zonation of the hilly area of medvenica mt. at the area of the zagreb city – in croatian].– geotehnika­geoexpert, zagreb, croatia, 107 p. polak, k., nonveiller, e., klemenčić, b. & lorencin, lj. (1971): studija sanacije klizišta jelenovac u zagrebu [remediation study of the jelenovac landslide in zagreb – in croatian].– in: proceedings of the 1st yugoslav symposium on hydrogeology and engineering geology, hercegnovi, yugoslavia, may 4–8, 1971. 165–172. razak, k.a., straatsma, m.w., van westen, c.j., malet, j.­p. & de jong, s.m. (2011): airborne laser scanning of forested landslides characterization: terrain model quality and visualization.– geomorphology, 126, 186–200. reutebuch, s.e., mcgaughey, r.j., anderson, h.e. & carson, w.w. (2003): accuracy of a high­resolution lidar terrain model under a conifer forest canopy.– canadian journal of remote sensing, 29, 527–535. santangelo, m., cardinali, m., rossi, m., mondini, a.c. & guzzetti, f. (2010). remote landslide mapping using a laser rangefinder binocular and gps.– natural hazards and earth system sciences, 10/12, 2539–2546. sassa, k. & he, b. (2013): txt­tool 3.081­1.2 landslide dynamics.– in: sassa, k., he, b., mcsaveney, m. & osamu, n. (eds.): icl landslide teaching tools.– international consortium on landslides, kyoto, japan, 215–237. schulz, w.h. (2007): landslide susceptibility revealed by lidar imagery and historical records, seattle, washington.– engineering geology, 89, 67–87. shan, j. & toth, c.k. (2009): topographic laser ranging and scanning: principles and processing.– crc press, taylor and francis group, boca raton, florida, 590p. sokolić, ž., hršak, a. & vlaić lončar, a. (2006): negativni utjecaji nekontroliranog odlaganja otpada na području podsljemenske zone u zagrebu [negative influence of uncontrolled waste disposals in the area of hilly zone of the zagreb city – in croatian].– in: milanović, z. (ed.): proceedings of the 9th international symposia of the waste management, zagreb, croatia, nov. 15–18, 2006. 1–22. stanić, b. & nonveiller, e. (1996): the kostanjek landslide in zagreb. – engineering geology, 42, 269–283. šagud, d. (2015): statistička analiza inventara klizišta podsljemenske zone iz 1979. godine [statistical analysis of landslide inventory of the podsljeme area from 1979 – in croatian].– unpubl. ms thesis, faculty of mining, geology and petroleum engineering, university of zagreb, 47 p. šikić, v. (1967): inženjerska geologija zagreb – sjever i jug [engineering geology zagreb – north and south – in croatian] – croatian geological survey, zagreb, 152 p. šikić, k. (1995): geološki vodič medvednice [a geological guide to medvednica mt. – in croatian].– croatian geological survey and ina­industrija nafte, zagreb, 199 p. šikić, v., viljevac, ž. & bastalić, n. (1984): nastanak klizišta na kajfešovom bregu u zagrebu [origin of the landslides at the kajfeš hill in zagreb – in croatian].– in: proceedings of the 8th yugoslav. symposia on hydrogeology and engineering geology, budva, yugoslavia, september 18–22, 1984, 213–219. tofani, v., raspini, f., catani, f. &, casagli, n. (2013): persistent scatterer interferometry (psi) technique for landslide characterization and monitoring.– remote sensing, 5, 1045–1065. van den eeckhaut, m., poesen, j., verstraeten, g., vanacker, v., nyssen, j., moeyersons, j., van beek, l.p.h. & vandekerckhove, l. (2007): use of lidar­derived images for mapping old landslides under forest.– earth surface processes and landforms, 32, 754–769. van westen, c.j., castellanos abella, e.a. & sekhar, l.k. (2008): spatial data for landslide susceptibility, hazards and vulnerability assessment: an overview.– engineering geology, 102, 112–131. vrsaljko, d., pavelić, d., miknić, m., brkić, m., kovačić, k., hećimović, i., hajek­tadesse, v., avanić, r. & kurtanjek, n. (2006): middle miocene (upper badenian/sarmatian) palaeoecology and evolution of the environments in the area of medvednica mt. (north croatia).– geologia croatica, 59/1, 51–63. geol. c roat. 49/2 3 i i 3161 2 figs. 1 12 pis. zag reb 1996 1 sc;ellrific nore porosity, cementation, diagenesis and their influence on the productive capability of sandstone reservoirs in the sa va depression (croatia) proceedings .l asnh tade.j. zeljka maric-durekovic anci renala slavkovic key words: secondary porosity, cementati on, diage­ nes is, rese rvoir quality, petrography, sed imen to­ logy. abstract the sandstone rcsclvoirs in the sava depress ion lost their prima­ ry porosi ty through compaction and ccmci1f;:uion in the carly stage of diagenesis. disso lution events enlarged porosity and created reser­ voi rs ih:\( were composed mainly of secondary porosity. but some zones of these reservoirs were destroyed by prec ipitat ion of late fe­ ri ch c'l lc ilc and dolomite cement. three groups o f sandstones differ­ ing in reservoir quality arc ide ntified hi ghly poro us litharcnitcs, lilharc nil cs wi th int crmed iat e porosi ty, and wcakly poro ll s, hi ghl y ccmcntcd lit harcnitcs. the type of porosity depends on the clay con­ tent in sand stones, whi ch is the resu lt of water energy and deposilio­ llill ellv ironment. 1. i 'troduction regional influences on reservoir qua lity inc lude depos iti onal e nviron ment, initial composition o r ille sand and associated muds, texture, lime, subsidence rate, pressure, thermal gradient , pore fluid compositi on and diagenetic hi story (lo ucks et al.. 1985). 'file main purpose of this study is to investiga te dia­ genetic processes and their influence on reservoir prop­ erti es or o il-gas fi e ld s in the sava depression (fi g. 1). the similariti es in diagenetic and reservo ir properties characterizing these rocks permit the development or a diagenetic model that is of general applicability. in the cored intervals of all fields, oil -bearing sand­ stones and \ve ll cemented sandstone zones were noticed (fig. 2). these dirrerences were st udied in detail. 2. geological setting the sava depression is located some 40 km south­ east from zagreb (fi g. i) and consists of a few oil-gas field s where hydroca rbons accumulated lt1 upper miocene sandstonc-marlstone sequences. ina -nart'lpji n. laboratory research dept., lovinciceva i , hr 10000 zagrcb, cro;hia. kljucne rijeci: sckundarni porozitet, cemet1lacija, dija­ geneza, kvaliteta rezervoara, pelrogra fija , sedime­ ntologija. sazetak vcci na primarnog porozile ta pjescanih rc.lcrvoara savske <lepre­ s ijc ncs lal a je zbog kompakc ijc i ccmen l<lcijc ii ranom sladiju dija­ ge nc7.e. naknadni proccsi otapanja doveli sll do s ivaranja sekun ­ darnog porozilcla, ali nckc zone promatranih rczcrvoara su uni s tcnc prccipilacijom kasnodijagenclskog fcrokalcilnog i clolomitnog ce mcn ta. s obz irorn na svojstv a reze rvoara izdvojcnc sll tri grllpc pjcscenjaka jako porozn i litoareni ti , lit oareni ti sa srcdnjim vrijed­ nosti11la poroziteta i s!abo porozni , cv rsto ccrncnlirani lil 0arcnili. vri­ jednosli porozit cta ovi sne sll 0 sadrzaj u gjinc u pjesccnjaei11la, sto jc ii vc7.i s energijo11l vode i uvjctima talozcnja. the dis tribu tion and geomet ry or sandst one bodies were strongly in iluenced by depositional palaeoenviron­ ment , delt aic and shelf processes. depos ition o r iva­ sandstones from the ivan ic producti on field ocemed on a shallow indented shelf, where elonga te, lenticular, sheet-like and chanel-fill ed sa nd bodies, as well as intcrbar and shelf marl s have been developed (tadej & krizmanic, 1995 ). the poljana sandstones of the zu ti ca field are interpreted as a dendritic palaeod rainage pattern characterized by the three major channel sand­ stone bodies (safflc et a i. , 1995). thicknesses or the separate sand bodies in the sava depress ion vary from few melres lip to several hundred metres. 3. methodology sandstone samples from a few hundred metre cored intervals of different productive fonnations were chosen [or in tensive study. standard core descriptions of litho­ logy and structural characteristics were performed. sev­ eral hundred thin-sections were exam ined wi th optical microscopy to determine mineral compos ition and porosity. thin-sect ions were stained with both alizarin rcd-s and potassiulll fcrricyanide 1'01' the purpose or car­ bonate minera l identificati on . routine point counts were done to quantify mineral composition and thin-sec tion porosity. grain s ize and so rting were determined. ]12 osijeka vukovar dubrovnik fig. 1 the position or oil-gas liclds in sava depression. porosity and permeabili ty were measured on corc plugs. selected samples were analyzed with scanning electron microscope (sem) for mineral composition, microporosity and di agenetic products, and with x-ray diltractometar [or mineral composition. 4. petrography the sandstone reservoirs in the sava depression are fine to medium grained (0.08-0.4 mm), most ly well sorted. no major composit ional variations arc observed when two fields are compared . mineralogically, the sandstones arc relatively uniform, aside from various amounts of earbonatc cements and clays. sandstones mostly consist of quartz and dolomite rock fragments. less abundant arc micas, altered feldspars, chlorite, and chert, quartzite and mica-schist rock fragments. sandstones can be differentiated in their cement composition and proportion. early diagenetic calcite cement is rarely preserved. detrital grains appear to be "floating" in calcite (plate i, fig. 1). in highly porous sandstones (plate i, fig. 2) micropores are sporadically filled with fe-dolomite and fe-calcite, and some clay minerals. late carbonate cements (plate i, fig. 4) infill­ ing sccondary i11lergranular pores are commonly fe­ rich (pc-calcite, fe-dolom ite). unlike early poikilotopic fc-calcite, this late cement incilled residual pore spaces that remained after compaction . point count analyses indicate the typical major com­ ponents of sandstones arc quartz (40-50%), rock frag­ ments ( 15-25%). micas (10-15%), feldspars (5-10%) and cement (5-20%). x-ray diffraction gave semiquan­ titative analyses of sandstone comparable with petro­ graphic and point co unt data. sem analysis displayed variat ions of c lay mineral content in the productive geologia croatica 49/2 l1lholo{o' porosity p=""',"t~ ilthorades fig. 2 schematic column correlation of sedimentary, diagenetic and reservoi r properties or upper miocene litharcni[cs in sava depression. legend: t) lili1arcnilc with less than 5% cement and high permeability (30-380 x 10·\t1112 ); 2) lilharenite with 5-10% cement and intermed iat e permeability (7 -105 x 10 \un'); 3) lilharcilite, lightly cemented (up to 20% cement), with very low permeability (0.05-10 x 1o-3mm2 ). sandstones and well cemented sandstones. in porous oil saturated zones illite, in the form of coatings and pore fillings (plale ii , fig. i) , and pore filling kaolinite (plate ii, fig. 2) were determined. in strongly cemented sandstones clay minerals are sporadically present. s. porosity and diagenesis in the burial history of sands much of the porosity is lost through compaction and cementation processes. early carbonate cemellt, primarly calcite may be inter­ preted as pre-compaction, inasmuch as the detrita l sand grains appear to be "floating" in calcite. these ccments are rarely preserved. dissolution of early diagenetic calcite cement and unstable grains is the main secondary porosity forma­ tional event. it has been suggested (schmidt et ai., 1979) that the primary agent responsible for carbonate dissolution in the subsurface is carbonic acid formed by the generation of carbon dioxide durin g the thermal maturation of organic matter in sediments . shale com­ paction yields large volumes of water that may be avail ­ able for dissolution reactions in sandstones . it is proba­ ble that the more porous horizons were never comple­ tely cemented with calcite, and intergranular porosity has been enhanced there by dissolution of some calcite. in well cemented zones , late carbonate cements infilling secondary pores are commonly iron-rich. their occurrence is probably related to the release of iron and magnesium [rom the illitization processes in adjacent shales (boles & franks, 1979). carbonate cement distribution depends on the clay content in sandstones, as wei[ as to the proximity of the shales that presum­ ably sourced the material for cementation, both dcpend­ ing on depositional processes. tadcj, maric-durckovic & sjavkovic: porosity, cementation, diagenesis ,md their lnr1ucnce ... 313 other diagenetic processes such as quartz over­ growths, precipitation of kaolinite from pore fluids , alteration or feldspars, late chlorite and pyrite formation are volumetrically minor and/or locally significant. 6. reservoir quality variation in porosity and permeability at depth is a function of sedimentary conditions, cementation and dissolution. the relationship between sandstone body geomet ry and the distribution of diagenetic clements are critical aspects of reservoir heterogeneity. in all studied fields sandstones can be divided into three groups differing in cementation rate and porosity­ permeability patterns. in first group are sandstones with icss than 5% cement, and with high porosity (23-33%) and permeability (30-380 x !o.3~m2) values. micro­ porosity is high, and pore sizes of 50 ~lm 0.1 mm pre­ dominate. the sccond group arc sandstones with 5-10% cement and average porosity 19-30% and pcrmeability 7-105 x 1o-\lm2 . pore sizes vary from 10-50 p.m. high­ ly ccmented (up to 20 % cement) and fortu nately lcss abundant are sandstones of the third group. porosity and permeability values arc very low (porosi ty 2-3%, permeability 0.05-10 x [0-3p.m 2 ). microporosity is poor with pore dimensions of 0-1 0 ~lm. although there are no significant variations in detri ­ tal mineralogy of all three sandstone groups, some dif­ ferences can be highlighted. primarly, it is the clay con­ tent that mostly depends on water energy and deposi­ tional conditions. in general, the fairweather clay rich sediments are weakly cemented, and the clay poor storm deposits well cemented (kantorowicz et al. . 1987). carbonate cementcd layers can be recogn ized in logs becausc they generate very high resistivity peaks. definition of lateral extension of these cemented layers is important because thcy reprcsent barriers for oil dis­ placement. 7. conclusion using a combinalion of petrographical, petrophysi ­ ca l and sedim cntological techniques, diagenetic processes can be identified . the similarit ies in the geo­ logical evol ution of reservoirs resulted in recognizable and ubiqu itous diagenetic processes. definition of depositional environments, body geometry, lateral extension and diagenetic processes are leading to better understanding of reservoir properties, and have to be assesscd during the evaluat ion of new exploration prospccts . 8. references boles. j.r. & franks, s.g. (1979): clay diagenesis in wilcox sandstones of southwest texas: implica­ tions or smectite diagenesis on sandstone ccmenta­ tion. jour. sed. petrology, 49, 55-70. kantorowicz. j.d .. bryant, ld. & dawans. j.m. (1987): controls on the geometry and distribu­ tion of carbonate cements in jurassic sandstones: bridport sands, southern england and wiking group, troll field, norway.in: marshall. j.d. (cd.): diagenesis of sedimen tary sequences. 103118, blackwell scientific publications. oxford. loucks. r.g .. dodge. m.m. & galloway. \v.e. (1985): regional controls on diagenesi s and reservoir quality in lower tertiary sandstones along the texas gulf coast.in: mcdonald. d.a. & surdam, r.c. (cds.): clastic diagenesis. aa pg memoir. 37. 15-46. safflc. b., velic. j .. simon. j. & novak. j. (1995): high-resolution paleogeographic maps of sandstone reservoirs: gss poljana (pontian, miocene), zutica oil & gas field , sava depression.­ first croatian geological congress, proceedings, 2, 529-533. zagreb. sc hmidt. v .. mcdonald. d.a. & platt, r.l. (1979): the role of secondary porosity in the course of sandstone diagcnesis.in: sc holle. p.a. & sci-iluger. p.r. (cds.): aspects of ciiagenesis. society of econom ic paleontologist and mineralo­ gis t, special publications, 26, 185-207. tadej, j. & krizmanic. k. (1995): paleoecology and depositional environments of the upper miocene sediments in the nw part of sava dcpres­ sion. first croatian geological congrcss, proceed­ ings. 2, 605 -608. zagreb. ~14 geologia cro:liic:l 49n plate i fi g. i litharenite with early diagenet ic calcitc ccment (reel). some of the sand grains are nearly surrounded by, or appear to bc " floating" in thc calc itc cement. rig.2 lli ghly porous, oil -saturated (brown) litharenite. first group of sandstones with high reservoir quality. fi g. ::; litharen ite with moderate porosity and cementati on. second group of sandston es wit h medium reservoir quality. fi g.4 hi ghly cemented (fe-dolom ite, blue) weakly porous litha renites. third group of sandstones with [ow reser­ voir quali ty. plate ii fi g. i sem phololllie rograph of illi te in the ro rm or a grai n coating. pig. 2 sem photomicrograph of pore fillin g kaolinite. note abundant inlergranular porosity. t;lucj, maric-d urekovic & si;lvkovic plate l 315 0.5 mm 3 16 plate ii geologi:l cro:l ticn 49/2 2016 | 69/2 | 205–212 | 2 figs. | 5 tabs. | www.geologia-croatica journal of the croatian geological survey and the croatian geological society traces of drilling predation in the upper badenian (middle miocene) molluscs from the rakovica stream (belgrade) meri ganić1, predrag radović2, ljupko rundić1, katarina bradić2 and slobodan knežević1 1 university of belgrade, faculty of mining and geology, department of regional geology, belgrade, kamenička 6, serbia; (corresponding author: meri.ganic@rgf.bg.ac.rs, ljupko.rundic@rgf.bg.ac.rs, slobodan.knezevic@rgf.bg.ac.rs) 2 national museum kraljevo, trg svetog save 2, serbia; (pedja_radovic@yahoo.com) 3 university of belgrade, faculty of mining and geology, department of paleontology, belgrade, kamenička 6, serbia; (bradic.kaca@gmail.com) doi: 10.4154/gc.2016.14 abstract the palaeoecology of fossil molluscs of serbia is insufficiently studied. drilling predation indicates interactive relationships among middle miocene badenian molluscs from the rakovica sands. these sands are present in the rakovica stream valley (southern part of belgra de), and well-known data about the fauna has existed since the end of the xix century. the collected material (one bulk sample) from the sec tion was used for studies that included 2301 shells of molluscs (1617 of gastropods and 684 of bivalves). among them were specimens with predatory drill holes. determining the value of drilling frequency (df) and prey effectiveness (pe) facilitates identification of the rela tionship between shell-drilling predators and their prey. based on analysis of the overall association, carnivorous gastropods were do mi nant in the sample, comprising more than fifty percent (52.32%) of all gastropod specimens. in addition, they constitute a large percentage of the total sample (43.19%). the largest number of victims was observed among bivalves, which are indicated by a df of 16.96%. the results were compared with other localities of miocene age in paratethys and with studies on the miocene sediments from the boreal and the atlantic provinces. these comparisons show that pe and df are very similar to results from the central paratethys, but that they are significantly higher than in the other are as mentioned. 1. introduction traces of biotic drillings found on skeletons of marine invertebrates provide arguably the richest source of quantifiable data on prey-predator interactions available in the fossil record (ko walewski, 2002). indeed, many studies of biotic interactions in the geological past have focused on drilling predation (vermeij, 1982, 1987; vermeij & dudley, 1982; baumiller, 1996; hoffmeister & kowalewski, 2001; sawyer & zuschin, 2011; chattopadhyay & dutta, 2013). the overall patterns of drilling predation are well established on ce no zoic molluscs from the atlantic coast of north america (kelley & hansen, 1993, 1996, 2006), but there has been considerably less works conducted in europe. relevant studies of drilling predation on molluscs from the miocene of central paratethys (hoffmeister & kowalewski, 2001; sawyer & zuschin, 2011) did not include any data from serbia, so details of predator-prey interactions in the marine middle miocene from this part of the southeastern margin of the pannonian basin remained largely unknown. the rakovica stream („rakovički potok”) near belgrade re­ presents one of the richest middle miocene (badenian) fossiliferous sites in serbia and has been the subject of geological and palaeontological studies for more than a century. pavlović (1890, 1893, 1922, 1925) and pavlović & petković (1903) studied the fossil fauna itself, while luković (1922), ste va­ no vić & stepanović (1939), stevanović (1951) and e re mija (1977, 1987) focused mainly on the stratigraphy of the site in the regional comparative context. pavlović (1925) was the first to note traces of biotic drillings on fossil specimens from the rakovica stream. he discovered that drilled shells belonged to ten gastropod and four bivalve species, and he assumed that these biotic boreholes were produced by predatory snails (natica and conus) found among other taxa on the site. later study by kohn (1983) reported that drilling predation is characteristic for naticidae and muricidae. similar palaeoecological observations were discovered by stevanović (1970), who de scribed traces of predation on badenian shells collected in the vicinity of belgrade, and more recently by jovanović (2002), who examined a badenian fauna from golubac, north-eastern serbia. however, none of these studies focused on drilling predation and they were not carried out in a systematic manner. in order to fill this gap in knowledge, we present here the first detailed report of predatory behaviour within molluscs from the middle miocene of serbia, which includes the comparison with the available data for paratethys, and the boreal and north atlan tic provinces (hoffmeister & kowalewski, 2001, kelley & hansen, 2006, sawyer & zuschin, 2011). 2. geologic setting the fossil sample used for the study was collected from the rakovica stream section, („rakovički potok”) located on the left bank of rakovica creek in the southern part of belgrade (wgs 84, 44°43′58″, 20°30′27″). in serbia, the site represents a classic locality of the sandy facies of the badenian (middle miocene), the so-called rakovica sands which are rich in marine fossils. it is located on the basic geological map at scale 1:100000, sheet pančevo (ivković, 1966). this area, based on main stratigraphic and tectonic studies, is a composite geological setting represented by block (horst and graben) structures. in this relatively article history: manuscript received august 06, 2015 revised manuscript accepted january 27, 2016 available online may 16, 2016 keywords: gastropods, bivalves, statistical analysis, predator-prey interactions, palaeoecological relations g eo lo gi a c ro at ic a geologia croatica 69/2206 small area and during the younger phases of neoalpine tectonics there were significant different movements which formed a mo­ dern relief. the torlak hill is a horst structure with mesozoic rocks in its core part, while the slopes are composed of different badenian and sarmatian deposits (marović et al., 2007). further downstream from the avala road, in the middle part of rakovica stream, there is a small graben structure which is part of the beli potok graben, which is filled with the upper miocene sediments (pannonian and pontian) as well as those of middle miocene (sarmatian) age. the torlak horst and the beli potok graben are separated by the so-called rakovica fault. these geological structures are characterized by large differential movements along the fault with a vertical displacement of more than 200 m. for example, in borehole kgk-14 below the pontian sediments, at an altitude of 100 m, the pannonian marls were discovered (kneže vić, 1989). however, just a few hundred metres away to north-east, in the torlak foothill, the same pannonian marls occur on the surface near 210 m. similarly, at the top of torlak hill, badenian sediments are present at the surface at 336 m. all tectonic movements took place during the late miocene and pliocene as well as the early pleistocene. based on strong vertical displacement along the block structures (uplift/subsidence) a composite hilly relief of this area was created. the rakovica sands are composed of a single uniform deposit, with a maximum thick ness of 3 m at the studied exposure (fig. 1). the section has no visible layers. it is dominated by grayyellow quartz sands with unevenly distributed fossils, and poorlycement ed sands with hard sandstone lenses. the faunal assemblage of this locality is rich, both in terms of numbers and diver sity of taxa, consisting of gastropods, bivalves, foraminifers, corals, bryozoans, ostracods, annelids, crabs (fragments of pincers), scaphopods, sea urchins (spine fragments), fish otoliths and shark teeth. biostratigraphically, based on foraminifers, the sands from the rakovica stream belong to the elphidium crispum–ammonia viennensis ecozone, the upper badenian stage (petrović, 1985; petrović & šumar, 1990). the main taxa among forams includes: elphidium cris pum, el. fichtelianum, ammonia vien nensis, borelis melo, spiroli na austriaca, asterigerinata plan orbis, cibicidoides cf. lobatu lus, lenticulina sp., quinquelo­ culina sp., planostegina sp. more over, numerous ostracods including aurila punctata, a. cicatricosa, cle to cythereis haidin­ geri, falunia plicatula, cnestocythere trun cata, costa edwardsi, tenedocythere sulcatopunctata, pokor nyella deformis, bairdo­ pipilata subdeltoidea, loxoconcha has tata, callistocythere ca­ nalicullata, etc. were found. a similar exposure is located in the belgrade city centre, beneath the belgrade fortress, where the sands lie next to the miocene marine reef „kalemegdan” (a geoheritage site), mostly composed of coralline alga lithothamnium (eremija, 1977). although it forms a part of the same geological unit (the rakovica sands), the faunal assemblage from the belgrade fortress is not nearly as rich as in the rakovica stream. nevertheless, it would be interesting to sample this exposure too, but since it is located in the zone of the protected geoheritage site, this was impossible. since the exposure is relatively small and lithologically uniform, and because it will probably become a geoheritage site soon, we did not want to damage the site by taking multiple samfigure 1. a simplified geographic position and location of the studied area. figure 2. a general stratigraphic column of the miocene of belgrade area (modified after schwarzhans et al., 2015). a gray rectangle marks the stratigraphic position of the studied sediments. age of the badenian regional stage based on hohenegger et al., 2014. g eologia c roatica ganić et al.: traces of drilling predation in the upper badenian (middle miocene) molluscs from the rakovica stream (belgrade) 207 ples. therefore, after we conducted a detailed examination of the entire exposure, we decided to collect only a single sample from the small surface of the vertical profile, located between 0.5 and 1 m from the accessible foothill (fig. 2). 3. materials and methods the sample (bulk sediment) of about 10 kg was brought back to the laboratory for study. the sediment was processed using fine­ mesh screens (0.15 to 0.80 mm) with seven sieves. bivalves and gastropods were retained on screens 0.8; 0.7; and 0.6 mm. traces of drilling have been identified on shells larger than 0.7 mm. all mollusc specimens were counted and examined for evidence of drilling predation under a binocular magnifier (reichert), with 20 x magnification for small and 2 x for large specimens. initially, we counted the abundance at the different taxonomic levels (species, family, class and total). the frequencies of predator-prey interactions in the sample were analysed by calculating drilling frequency (df), measuring the rate of prey mortality due to drilling predation, by dividing the number of specimens that contain at least one successful predation trace (ds) by the total number of specimens in the sample (n). for bivalves, the total number of specimens had to be corrected by dividing it by 2, in order to understand disarticulation of the shells after death. df was calculated at family level (lower taxon frequency according to kowalewski, 2002), but also at class and total assemblage levels (assemblage frequency according to kowa lewski, 2002). escalation parameters, (estimates that provide some measure of the predator’s failure, or rather a prey’s ability to resist predators), were assessed by calculating a relative frequency of failed predator attacks. this frequency is often refer red to as prey effectiveness (pe), and is calculated by dividing the number of traces of unsuccessful attacks (id) (incomplete, repaired and healed drill holes) by the total number of drilling attempts (id plus number of complete drill holes, d) (kowa lewski, 2002; sawyer & zuschin, 2011). chi-squared tests were used to compare drilling frequencies (on total-assemblage, class and fami ly levels) and prey effectiveness (on total-assemblage and class levels) from the rakovica sample with those published for paratethys and other miocene basins (hoffmeister & kowa lew ski, 2001; kelley & hansen, 2006; sawyer & zuschin, 2011). at family level, only data for the central paratethys (sawyer & zuschin, 2011) were available. a 5% significance criterion (α = 0.05) was applied to our statistical analysis, and an online interactive calculation tool was used for the chi-square tests (preacher, 2001). 4. results a total of 2301 mollusc shells, consisting of 1617 gastropods and 684 bivalves, were recovered from the sample. 56 gastropod and 14 bivalve species (tables 1 and 2) were identified. evidently, gastropods dominated the sample both in terms of species richness and biomass. however, bivalves were more frequently attable 1. the list of species recovered from rakovica sample, with numbers of specimens/valves (n) in parantheses. class species (n) gastropoda acirsa drevermani (18), acteocina lajonkaireana (15), alaba costella anomala (127), alvania oceani (31), alvania productilis (1), ancilla glandiphormis (25), athleta ficulina (67), athleta pirulaeformis (5), athleta rarispina (10), bittium spina (95), buccinum limatum (11), calyptrea chinensis (7), cerithiopsis bilineata (1), cerithiopsis opaca (15), cerithium crenathum (17), cerithium procrenatum (6), clavatula capgrandi (10), clavatula asperulata (29), conus dujardini (21), conus fiscocingulathus (96), conus granularis (2), euthria intermedia (5), fusinus subrugosa (6), fusinus valenciensis (1), hydrobia hoernesi (116), mangelia perpulchra (25), marginella cratoformis (27), marginella haueri (7), marginella minuta (10), mitrella bitneri (32), mitrella fillisae (6), mitrella hilberi (53), murex granularis (3), nassa badensis (81), nassarius seraticosta (78), natica millepunctata (22), natica redempta (27), neritina picta (21), odontostoma plicatum (10), oxistella patula orientalis (96), piramidella plicosa (12), retusa truncatula (69), ringicula bucinae (6), rissoa turricula (42), rissoina pusilla (8), sandbergeria perpusila (125), scala tenuicosta (2), scaphander lignaris (1), strioterebrum basteroti (7), terebra fuscata (2), turicula miocenica (13),turris disjuncta (18), turritella badensis (6), turritella bicarinata (2), turritella subangulata (41), turritella subangulata pulchra (8) bivalvia glycymeris glycymeris (91), cardites partschi (35), euripicardium multicostatum (22), clausinella basteroti (22), loripes dentatus (158), anadara diluvii (62), nucula (nucula) nucleus (17), gouldia minima (168), tellina donacina (41), linga (linga) collumbela (14), corbula carinata (24), parvicardium papillosum (2),cubitostrea digitalina (9), glycymeris obtusata (19) table 2. taxonomic summary of drill hole data from mollusks from the rakovica site for the overall assemblage, classes and families. n = abundance (corrected to account for disarticulated bivalves), ds = number of shells with complete drill holes, d = number of complete drill holes, id = number of incomplete drill holes, df = drilling frequency, pe = prey effectiveness. n ds d id df (%) pe (%) total assemblage 1959 214 226 19 10.92 7.76 class gastropoda 1617 156 168 13 9.65 7.18 class bivalvia 342 58 58 6 16.96 9.38 gastropod families epitoniidae 18 1 1 0 5.55 0 cylichnidae 16 3 3 0 18.75 0 litiopidae 127 13 13 0 10.24 0 rissoidae 84 11 11 2 13.09 15.38 olividae 25 5 5 0 20 0 volutidae 82 0 0 0 0 – cerithiidae 118 17 17 2 14.41 10.53 buccinidae 16 2 2 0 12.5 0 calyptraeidea 7 2 2 1 28.57 33.33 cerithiopsidae 16 3 3 0 18.75 0 turridae 82 6 7 0 7.32 0 conidae 119 4 6 0 3.36 0 fasciolariidae 7 1 1 0 14.28 0 hydrobiidae 116 7 7 0 6.03 0 columbellidae 38 4 4 0 10.53 0 mitridae 53 7 7 0 13.21 0 muricidae 3 0 0 0 0 – nassaridae 159 8 8 0 5.03 0 naticidae 49 3 3 1 6.12 25 neritidae 21 0 0 0 0 – pyramidellidae 22 5 5 2 22.73 28.57 trochidae 96 2 2 1 2.08 33.33 retusidae 69 22 31 0 31.88 0 ringiculidae 6 0 0 0 0 – scaliolidae 127 16 16 2 12.6 11.11 terebridae 9 0 0 0 0 – turritellidae 75 13 13 1 17.33 7.14 marginellidae 44 1 1 1 2.27 50 clavatulidae 13 0 0 0 0 – bivalve families glycymerididae 55 3 3 1 5.45 25 carditidae 17.5 4 4 0 22.86 0 cardiidae 12 1 1 0 8.33 0 veneridae 95 11 11 1 11.58 8.33 lucinidae 86 31 31 2 36.05 6.06 arcidae 31 5 5 0 16.13 0 nuculidae 8.5 2 2 0 23.53 0 tellinidae 20.5 0 0 2 0 100 corbulidae 12 0 0 0 0 – ostreidae 4.5 1 1 0 22.22 0 g eo lo gi a c ro at ic a geologia croatica 69/2208 tacked than gastropods, since drilling frequency was higher in the former (16.96%) than the latter (9.65%). in terms of prey effectiveness, bivalves (9.38%) were able to resist predator attacks more successfuly than gastropods (7.18%). the most abundant gastropod families (table 2), with more than 115 specimens in the sample, were nassaridae (159), liti­ opidae (127), scaliolidae (127), conidae (119), cerithiidae (118) and hydrobiidae (116). with numbers between 96 and 44, the following families were also relatively numerous: trochidae (96), rissoidae (84), volutidae (82), turridae (82), turritellidae (75), mitridae(53), naticidae (49) and marginellidae (44). with abundances between 38 and 13, columbellidae (38), olividae (25), py ramidellidae (22), neritidae (21), epitoniidae (18), cylichnidae (16), buccinidae (16), cerithiopsidae (16), cylichnidae (16) and clavatulidae (13), were much less abundant. six families were represented by less than 10 shells – terebridae (9), calyptraeidea (7), fasciolariidae (7), ringiculidae (6) and muricidae (3). six of 29 gastropod families were never drilled, but only two of those had abundances greater than 20 (volutidae and neritidae). among the attacked families, the df ranged from 2.08% (tro­ chidae) to 31.88% (retusidae). incomplete drill holes were observed in nine families, with pe ranging from 7.14% (turritelli­ dae) to 50% (marginellidae); however, there were only one or two incomplete drillings per family. most families were attacked between one and 19 times (succesful plus unsuccesful attacks); the notable exception were retusidae, with 31 complete, but no incomplete drill holes. multiple drill holes were found in three families (turridae, conidae, retusidae). three bivalve families dominated the sample (table 2) – ve­ ne ridae (95), lucinidae (86) and glycymerididae (55). the arci­ dae were represented by 31 specimens, tellinidae with 20.5 and corbulidae had 12; nuculidae and ostreidae had less than 10 spe cimens (8.5 and 4.5, respectively). the abundance data was corrected to account for disarticulated bivalves. only one of 10 bivalve families was never drilled (corbulidae), while one family showed traces of only two failed drilling attempts (tellinidae). among those drilled, the df ranged from 5.45% (glycymeridi­ dae) to 36.05% (lucinidae). incomplete drill holes were pre sent in four families, with the pe ranging from 6.06% (lucinidae) to 100% (tellinidae); however, as in gastropods, there were no more than two ids per family. most families were attacked (succesful plus unsuccesful attacks) five times or less, except for the luci­ nidae and veneridae, with 33 and 13 attacks, respectively. no multiple drill holes were observed on bivalve shells. based on our analysis (table 3) the total (mollusc) assemblage-level drilling frequency for the rakovica sample (10.92%) is lower than the df reported for the paratethys province (15.2%) and significantly (two/three­fold) lower than those reported for the boreal (22.4%), southeastern north atlantic (23.5%) and us atlantic coast (34.4%). however, the total assemblage-level df for rakovica is higher than the value reported for central paratethys (7.5%). these differencies were all statistically significant, as showed by the chi-square tests. comparisons of the assemblage-level df for gastropods quite gave similar results and all differences were also statistically significant (table 3). alternatively, the assemblage-level df values for bivalves, showed that only two comparisons were statistically significant. the df for the rakovica sample (16.96%) is almost two times higher than the df reported for the lower/middle miocene of the central paratethys (8.6%). conversly, the df for bivalves is two-fold lower than the df reported for the us atlantic coast (34.1%). examination of the drilling frequencies for the rakovica and central paratethys samples at the family­level, statistically significant dif­ ferences only existed for three taxa (table 4). among the gastropods, the cerithiidae were drilled almost twice as frequently in the rakovica sample than in central paratethys (dfs are 14.41% and 7.6%, respectively). among bivalves, the veneridae show similar differences (df in rakovica sample is 11.58%, com pared to 7.6% in central paratethys). lucinidae were drilled five times more frequently in the rakovica sample than in the central paratethys province (dfs were 36.05% and 7.1%, respectively). table 3. statistical comparisons of total and phylum assemblage-level drill frequencies using chi-squared test. c2 = chi-square. bold p-values are statistically significant at α = 0.05. level sample drilled undrilled df (%) c2 p-value source total assemblage rakovica 214 1745 10.92 – – present study central paratethys 2324 28636 7.5 30.24 < 0.00001 sawyer & zuschin, 2011 boreal 386 1336 22.4 88.71 < 0.00001 hoffmeister & kowalewski, 2001 paratethys 156 868 15.2 11.5 0.000696 hoffmeister & kowalewski, 2001 southeastern north atlantic 27 88 23.5 16.67 0.000045 hoffmeister & kowalewski, 2001 us atlantic coast 11483 21945 34.4 458.99 < 0.00001 kelley & hansen, 2006 gastropoda rakovica 156 1461 9.65 – – present study central paratethys 1596 20698 7.2 13.75 0.000209 sawyer & zuschin, 2011 boreal 284 875 24.5 111.72 < 0.00001 hoffmeister & kowalewski, 2001 paratethys 84 515 14 8.66 0.003242 hoffmeister & kowalewski, 2001 southeastern north atlantic 22 45 32.8 36.59 < 0.00001 hoffmeister & kowalewski, 2001 us atlantic coast 4048 7573 34.8 415.48 < 0.00001 kelley & hansen, 2006 bivalvia rakovica 58 284 16.96 – – present study central paratethys 726 7747 8.6 28.562 < 0.00001 sawyer & zuschin, 2011 boreal 102 461 18.1 0.196 0.657969 hoffmeister & kowalewski, 2001 paratethys 72 353 16.9 0 1 hoffmeister & kowalewski, 2001 southeastern north atlantic 5 43 10.4 1.33 0.248805 hoffmeister & kowalewski, 2001 us atlantic coast 7435 14372 34.1 44.167 < 0.00001 kelley & hansen, 2006 ganić et al.: traces of drilling predation in the upper badenian (middle miocene) molluscs from the rakovica stream (belgrade) 209 g eologia c roatica due to the small number of unsuccessful drilling attempts (id) in our sample and the lack of the appropriate comparative data, prey effectiveness could only be studied and tested for statistical significance in a very limited manner (table 5). on the total assemblage-level, molluscs from rakovica were less able to resist predator attacks than those from the boreal and parathethys province in general. when compared to central paratethys, the frequency of failed predator attacks on gastropods alone show ed only a slightly lower value (pes for central paratethys and rakovica were 7.4% and 7.18%, respectively). compared to central paratethys (6.3%), bivalves from rakovica showed a high er pe value (9.38%). 5. discussion the study of predator-prey interactions by calculating and comparing drilling frequency and prey effectiveness data is a common and widely used approach in fossil and modern environments. although the drilling data for lower taxa (species, genus, family) probably provide the most biologically meaningful analysis of predator-prey interaction in the fossil record (kowa lewski, 2002), assemblage-level analysis is more useful in the pragmatic sense. this is because assemblage-le vel data can be computed for any fossil sample and thus can be used for analytical comparisons throughout the fossil record. however, assemblage-level analyses are quite problematic, since they often mix habitats, combine prey with different morphological and ecological characteristics and do not take into account other, fine­scale palaeoecological data. a detailed review of the advantages and disadvantages of this method is outwith the scope of this paper, but can be seen elsewhere (kowalewski, 2002; leighton, 2002; vermeij, 2002). in this paper, the assemblage-level, class-level and familylevel drilling data was calculated for the upper badenian strata at the rakovica stream in belgrade, and compared to available data for miocene provinces (central paratethys, paratethys in general, boreal, southeastern north atlantic and united states atlantic coast). this study is the first of this kind to be conduct ed on a sample originating from the southern part of the central paratethys province. as some of the published studies have already shown (hansen & kelley, 1995; hoffmeister & kowalewski, 2001; sawyer & zuschin, 2011), predation trace data from a single horizon, locality or province can vary significantly, due to the problem of spatial variation. this problem can possibly be solv ed by calculating average values derived from multiple samples (hoffmeister & kowalewski, 2001) and was used in this study. for the reasons briefly explained above, it was not possible to take multiple and spatially separated samples from the rakovica sands, therefore our sample may misrepresent the locality. however, the sample is relatively large (almost 2000 spe cimens) and there is a good chance that the sampling error is not high. based on the studies of lithological composition, presence of the diverse marine fauna (e.g. molluscs, foraminifers, and ostracods), and local palaeogeographical setting, it can be con clud ed with reasonable certainty that the rakovica sands represent ed a shallow marine (littoral) environment during late badenian time (maro vić et al., 2007). the waters in this part of central paratethys were warm, since they were positioned in the subtropical climatic zone (kovač et al., 2007). the presence of the warmloving benthic fish (family gobiidae) at the rakovica stream (nelson, 2006) supports this view. in this shallow water environment, the salinity was normal, with an occasional brackish influence, confirmed by discovery of the mixed assemblage of typi­ cal marine (corals, sea urchins) and euryhaline fau na (cerithidae, hydrobiidae and lucinidae). discovery of scarce fragments of corals and echinoderms also indicates more dynamic conditions, water fluctuations and higher energy of water than the salinity. some ostracods (callistocythere, aurila, loxoconcha) sug gest the upper part of the infralittoral zone (up to 40m, zorn, 2003). the rakovica ostracod fauna lived in shallow (about 50 m deep), warm, and clear waters, connected to a deeper sea, occasionally exposed to freshwater inflows. the finding of the foraminifer genus borelis indicates very warm water and implies tropical to subtropical water temperatures. a similar indication was given by szczechura & abd-elshafy (1988) and rundić (1992) from the badenian deposits of north africa and ne bosnia and herzegovina. somewhere, a very steep coast could be responsible for the extreme mixing of the marine fauna and also explains some brackish/terrestrial faunal elements at the sampling locality. table 4. statistical comparisons of family-level drill frequencies using chisquared test. bold p-values are statistically significant at α = 0.05. comparative data for the central paratethys comes from sawyer & zuschin (2011). family rakovica df (%) central para tethys df (%) c2 p-value rissoidae 13.09 10.9 0.398 0.53 cerithiidae 14.41 7.6 6.689 0.0097 turridae 7.32 8.6 0.119 0.730122 nassaridae 5.03 6.8 0.742 0.39 pyramidellidae 22.73 9.4 2.377 0.12 naticidae 6.12 12.9 1.88 0.17 veneridae 11.58 6 4.065 0.043781 lucinidae 36.05 7.1 58.459 < 0.00001 arcidae 16.13 4.7 3.776 0.051993 table 5. statistical comparisons of total assemblage and phylum-level prey effectiveness using chi-squared test. bold p-values are statistically significant at α = 0.05. level sample d id pe (%) c2 p-value source total assemblage rakovica 226 19 7.76 – – present study central paratethys 2324 165 6.6 0.45 0.502335 sawyer & zuschin, 2011 boreal 386 77 16.63 10.768 0.001033 hoffmeister & kowalewski, 2001 paratethys 156 3 18.87 6.449 0.011101 hoffmeister & kowalewski, 2001 gastropoda rakovica 168 13 7.18 – – present study central paratethys 1596 58 7.4 5.926 0.014919 sawyer & zuschin, 2011 bivalvia rakovica 58 16 9.38 – – present study central paratethys 726 107 6.3 4.466 0.034576 sawyer & zuschin, 2011 g eo lo gi a c ro at ic a geologia croatica 69/2210 most of the identified bivalve taxa lived as infauna, buried in soft substrate on the seabed. they were sustained by filtration of suspended food, such as plankton, algae and other water-borne nutrients and particles (cardiidae, veneridae, etc.), or by chemosynthetic bacteria (in the case of lucinidae). carnivorous gastropods dominated the sample, comprising more than fifty percent (52.32%) of all gastropod specimens, and also a large por tion of the total sample (43.19%). the most numerous of these were nas­ saridae, conidae, turridae and volutidae. two families of predators (naticidae and muricidae) that were most likely responsible for the drill holes were observed in our sample. these gas tropods gain access to the soft parts of the prey by the radula. our results on drilling intensity showed that bivalves from the rakovica sands were attacked almost twice as frequently as gastropods (table 2). this is probably related to the specific mode of life of these molluscs (infauna) and their enemies, naticids. alternatively, prey effectiveness data (table 2) indicates that the bivalves were more successful at resisting predator attacks. again, this may be because most bivalves from the sample lived as infauna, which is hard to reach for predators (barnes et al., 1988). in contrast, most of the identified gastropod prey lived as epifauna; and this makes them less accessible to infaunal predatory naticids, which constitute the majority of drilling predators in our study. most of the mollusc shells showed only traces of a single (successful) drilling attempt. multiple drill holes were found only in three gastropod families (turridae, conidae and retusidae) and only on a single specimen from each group. several scenarios could explain these cases of multiple drilling. we could imagine more than one predator attacking the prey at the same time, but it could also be the case that individual drillings were made at different times (kitschell, 1986), by the same or a different predator. also, a predator could have been attacking an empty shell (hoffman et al., 1974). unfortunately, experimen tal studies (hutchings & herbert, 2013) failed to solve this problem. six gastropod families (volutidae, muricidae, neritidae, ring i culidae, terebridae, clavattulidae) and one bivalve family (corbulidae) were never drilled; also, tellinidae showed only failed drilling attempts. this is probably because many of these lived buried deep in the sediment similar to the representatives of families tellinidae, corbulidae and volutidae and relatively thick shells (volutidae). the most numerous family (82 specimens) with no drillings on their shells were the volutidae; interestingly, one specimen that belonged to this family as reported by sawyer & zuschin (2011) also had no drill holes (although this could be just a coincidence, considering the small sample). here, naticids and muricids were considerably less abundant, forming 2.65% percent of the total sample. with just three specimens, the muricids were particularly rare. however, in the central paratethys sample published by sawyer & zuschin (2011), these two predator families together comprise only 1.6% of the total mollusc sample. a considerably higher percentage (4.2%) of these predators was observed by kelley & hansen (2006) in the u.s. atlantic costal plains. of course, we should keep in mind that these comparative figures were made on the basis of multiple samples from localities with different palaeoecological and stratigraphic settings. moreover, 49 naticid spe cimens were attacked; all of these drillings were probably made by the members of the same taxa, because naticids are known for cannibalism (chattopadhyay et al., 2014a).traces of predation muricids (a specific shape of drill hole; carriker, 1981) were only determined on four gastropod shells. for a more pre cise assessment, a more detailed analysis should be made (zło tnik, 2001, chattopadhyay et al., 2014a), but it seems highly unlikely that the lack of infaunal prey was the cause of cannibalism among the naticids. comparisons of total assemblage-level and class-level drilling frequencies (table 3) showed that the value for the rakovica stream was significantly lower than the data reported for the boreal, paratethys in general, southeastern north atlantic and us atlantic coast. however, the value reported for the central paratethys was lower than the value reported here. these differences could be due to the fact that samples come from different stratigraphic settings: the rakovica sands is upper badenian, the central paratethys sample comes from the karpatian – badenian, paratethys sample is from burdigalian – serravallian, and boreal, southeastern north atlantic and us atlantic coast are from middle – late miocene. other abiotic factors could also be responsible – differences in depth, seabed composition, salinity, temperature etc. alternatively, the central paratethys represent ed an epicontinental sea with specific evolution, which lasted for less time than the evolutions of other basins used in our comparative analysis (rögl, 1998); therefore, we can assume that fossil communities were also distinctive (harzhauser et al., 2003). this also means that communities of the central paratethys (sawyer & zuschin, 2011) and rakovica stream (which represents its southeastern part of central paratethys) are more similar to each other than to other basins; indeed, differences in df values seem to confirm this. also, we think that the higher df in this study, relative to the central paratethys, is in accordance with the littoral character of the locality, since there is a negative correlation between drilling frequency values and increasing depth (walker, 2001; tomašovych & zuschin, 2009). it is believed that drillings are more frequent in warm, tropical environments, where mollusc numbers and diversity are far greater than in cold waters (vermeij & roopnarine, 2001, chattopadhyay et al., 2014b). since there is actually a higher df in the relatively cold realms of the atlantic and boreal, temperature was not the main cause for the observed differences. in the case of the central paratethys (sawyer & zuschin, 2011) the low abundance of drilling predators may be a very good reason for low df. primarily, we must keep in mind that we are comparing a single locality with the cumulative data for entire marine realms, which included many datasets, from different types of sediments that were formed in different abiotic environments. this fact alone could be responsible for the large proportion of the differences observed. family-level df values in this study were compared with data from the central paratethys (table 4) and showed that ce­ rithidae, veneridae and lucinidae were drilled significantly more frequently in our sample; all of these taxa represent non-predatory (grazers, suspension feeders and chemosymbionts, respectively) and euryhaline taxa. their relatively high abundances and high dfs (especially for veneridae and lucinidae) could mean that they were preferred by predators; these taxa would have been more available in shallow waters with lowered salinity along the southeastern rim, than in the central paratethys in general. despite the methodological circumstances mentioned earlier, our comparisons of escalation data (table 5) showed that molluscs from the rakovica sands were possibly less successful in resisting predator attacks than those from boreal and paratethys provinces. this could be caused by biotic factors (such as a relatively higher number of predators etc.) or abiotic factors (such as a relative depth, seafloor composition etc.). when class­level esg eologia c roatica ganić et al.: traces of drilling predation in the upper badenian (middle miocene) molluscs from the rakovica stream (belgrade) 211 calation data from all parts of the central paratethys were compared with the se parts in belgrade, almost identical figures for gastropods were observed, while apparently bivalves from this study were more successful in resisting predator attacks. this too could be explained by the number of biotic and abiotic factors, or simply by a sampling artefact. 6. conclusion the analysis of predator-prey interactions in the southeastern part of central paratethys during the badenian was conducted on the sample from the rakovica stream locality (the rakovica sands) in belgrade. the fossiliferous sands were deposited in the littoral zone of a warm sea. the salinity in this part of the basin was normal, with an occasional brackish influence, as indicated by the mixing of typical marine and euryhaline faunas. from the biostratigraphic point of view, the rakovica sands belong to the el­ phidium crispum – ammonia viennensis ecozone (upper badenian). statistical analysis of the rich gastropod and bivalve communities showed that bivalves were more frequently attacked by drilling predators than gastropods. bivalves were also more successful in resisting predator attacks, probably due to the biotic factors, such as the dominant infaunal mode of life. predatory gastropods such as the naticidae and muricidae families were mostly responsible for the drill holes examined in our study, but muricids were particularly rare. in this study, comparisons with other miocene provinces showed that the details of predator-prey interactions, matched (with minor deviations) the central paratethys, which indicates relative uniform palaeoecological conditions in the basin. however, there are relatively small differences between our results and data from all the afore-mentioned parts of the central paratethys province. at the rakovica sands, there are higher df and pe values because we were dealing with a single sample (environment), with specific local conditions such as temperature, salinity, depth etc. in contrast, all the other data used for comparison were cumulative, based on samples from different en vironments – littoral versus sublittoral, and estuaries versus fully marine settings and different strata. other provinces mentioned here, show different results, both in terms of drilling intensities and escalation data. finally, we concluded that there is no general pattern for the interpretation of the palaeoecological conditions which have been responsible for the formation of different populations of fossil organisms and their predator – prey relationships. acknowledgment m. ganić, lj. rundić and s. knežević wish to thank the ministry of education and science, republic of serbia (project no. 176015) for supporting their contribution to this study. we also wish to express special gratitude to the reviewers for their constructive comments and suggestions that greatly improved an earlier version of the manuscript. references barnes, r.s.k., callow, p. & olive, p.j.w. (1988): the invertebrates: a new synthesis.– blackwell scientific publications, 118–133. baumiller, t.k. (1996): boreholes in the middle devonian blasoid heteroschisma and their implications for gastropod drillig.– palaeogeography, palaeoclimatology, palaeoecology, 123, 343–351. carriker, m.r. (1981): shell penetration and feeding by naticacean and muricacean predatory gastropods: a synthesis.– malacologia, 20/2, 403–422. chattopadhyay, d. & dutta, s. (2013): prey selection by drilling predators: a case study from miocene of kutch, india.– palaeogeography, palaeoclimatology, palaeoecology, 374, 187–196. doi: 10.1016/j.palaeo.2013.01.016 chattopadhyay, d., sarkar, d., dutta, s. & prasanjit, s.r. (2014a): what controls cannibalism in drilling gastropods? a case study on natica tigrina.– palaeogeography, palaeoclimatology, palaeoecology, 410, 126–133, doi: 10.1016/j. palaeo.2014.05.037 chattopadhyay, d., zuschin, m. & tomašovych, a. (2014b): effects of high risk environment on edge-drilling behavior: inference from recent bivalves from the red sea.– paleobiology, 40, 34–49, doi: 10.1666/13024 eremija, m. (1977): miocen u oblasti ekshumiranog mezozojsko-serpentinskog paleoreljefa, od rakovice do ripnja. [miocene in the exhumed mesozoic­serpentine area of palaeorelief, from rakovica to ripanj – in serbian].– in: petković, k. (eds.): géologie de le serbie. stratigraphie ii/3: 145–154. eremija, m. (1987): badenski kat [badenian – i serbian].– in: anđelković, m. (eds.): la géologie des environs de belgrade i, géologie et géodinamique, 151–172. hansen, t.a. & kelley, p.h. (1995): spatial variation of naticid gastropod predation in the eocene of north america.– palaios, 10, 268–278. doi: 10.2307/3515257 harzhauser, m., mandic, o. & zuschin, m. (2003): changes in paratethyan marine mollusks at the early/middle miocene transition: diversity, palaeogeography and palaeoclimate.– acta geologica polonica, 53, 323–339. hoffman, a., pisera, a. & ryszkiewicz, m. (1974): predation by muricid and naticid gastropods on the lower tortonian mollusks from the korytnica clays.– acta geologica polonica, 24, 249–260. hoffmeister, a.p. & kowalewski, m. (2001): spatial and environmental variation in the fossil record of drilling predation: a case study from the miocene of central europe.– palaios, 16, 566–579. doi: 10.1669/0883-1351(2001)016%3c0566: saevit%3e2.0.co;2 hohenegger, j., ćorić, s. & wagreich, m. (2014): timing of the middle mio cene badenian stage of the central paratethys.– geologica carpathica, 65/1, 55–66, doi: 10.2478/geoca-2014-0004 hutchings, j.a. & herbert, g.s. (2013): no honor among snails: conspecific competition leads to incomplete drill holes by a naticid gastropod.– palaeogeography, palaeoclimatology, palaeoecology, 379–380, 32–38, doi: 10.1016/j.palaeo. 2013.04.003 ivković, a., vuković, a., nikolic, j., kovačević, d., palavestrić, lj., petrović, lj., jovanović, o., trifunović, i. & sebinović, lj. (1966): osnovna geološka karta sfrj 1:100000, list pančevo l34­114 [basic geological map of sfry 1:100000, pančevo sheet – in serbian].– geološki zavod, beograd, savezni geološki zavod, beograd. jovanović, g. (2002): paleoecological and taphonomical features of badenian fauna of sladinci near golubac.– proceedings of geoinstitute, 37, 135–150. kelley, p.h. & hansen, t.a. (1993): evolution of the naticid gastropod predatorprey system: an evaluation of the hypothesis of escalation.– palaios, 8, 358–375. doi: 10.2307/3515266 kelley, p.h. & hansen, t.a. (1996): recovery or the naticid gastropod predatorprey system from the cretaceous-tertiary and eocene-oligocene extinctions.– geological society special publication, 102, 373–386. doi: 10.1144/gsl.sp.1996.001. 01.27 kelley, p.h. & hansen, t.a. (2006): comparisons of classand lower taxon-level patterns in naticid gastropod predation, cretaceous to pleistocene of the u.s. coastal plain.– palaeogeography, palaeoclimatology, palaeoecology, 236, 302– 320. doi: 10.1016/j.palaeo.2005.11.012 kitchell, j.a. (1986): the evolution of predator-prey behavior: naticid gastropods and their molluscan prey.– in: nitecki, m. & kitchell, j.a. (eds.): evolution of animal behavior: paleontological and field approaches oxford univerity press, oxford, 88–110. knežević, s. (1989): prinove iz ponta belopotočkog rova [new specimen from the pontian of beli potok trough – in serbian, summary in english].– ann. geol. pennins. balk., 53, 373–382. kohn, a.j. (1983): feeding biology of gastropods.– in: saleuddin, a.s.m. & wilbur, k.m. (eds.): the mollusca, edit. 5, physiology 2, 1–63. doi: 10.1016/b9780-12-751405-5.50009-9 kováč, m., andreyeva­grigorovich, a., barjaktarević, z., brzobohaty, r., filipescu, s., fodor, l., harzhauser, m., nagzmarosy, a., oszczypko, n., pavelić, d., rögl, f., saftić, b., silva, l. & studencka, b. (2007): badenian evolution of the central paratethys sea: paleogeography, climate and eustatic sea-level changes.– geologica carpathica, 58, 6, 579–606. kowalewski, m. (2002): the fossil record of predation: an overview of analytical methods.– in: kowalewski, m. & kelley, p.h. (eds.): the fossil record of predation. paleontological special papers, 8, yale university, new haven, 3–42. leighton, l.r. (2002): inferring predation intensity from the marine fossil record.– paleobiology, 28, 328–342. luković m. (1922): facije drugog mediteranskog kata u okolini beograda [second mediterranean facies from belgrade surroundings – in serbian].– ann. geol. pennins. balk., 7/1, 22–41. g eo lo gi a c ro at ic a geologia croatica 69/2212 marović, m., toljić, m., rundić, lj. & milivojević, j. (2007): neoalpine tectonics of serbia.– serbian geological society, ser. monographie, 87 p., isbn 978-86-86053-03-9 nelson, j.s. (2006): fishes of the world.– department of biological sciences, university of alberta, canada, 601 p. doi: 10.1002/9781119174844 pavlović, p.s. (1890): mediteranska fauna u rakovici [mediteranian fauna from the rakovica – in serbian].– ann. geol. pennins. balk., 2, 2, 9–60. pavlović, p.s. (1893): prinove geološkog zavoda [new specimen of geological sur­ vey – in serbian].– ann. geol. pennins. balk., 4, 186–191. pavlović, p.s. (1922): prilozi za poznavanje tercijara u srbij [contribution to the study tertiary in serbia – in serbian].– ann. geol. pennins. balk., 7/1 42–52. pavlović, p.s. (1925): o povredama na drugomediteranskim mekušcima iz srbije [breaches of the second mediteranian molluscs from serbia – in serbian].– ann. geol. pennins. balk. zapisnici srpskog geološkog društva, zbor 203, 18/1, 204–205. pavlović, p.s. & petković, k.v. (1903): prinove geološkog zavoda [new speci­ men of geological survey – in serbian].– ann. geol. pennins. balk., 6/1, 293–325. petrović, m. (1985): foraminiferske zone i loze badenskog kata okoline beograda [badenian foraminiferal zones and subzones in belgrade surroundings – in serbian, abstract in english].– ann. geol. pennins. balk., 49, 271–291. petrović, m. & šumar, m. (1990): biostratigrafski pregled sarmata okoline beograda [biostratigraphical overview of the sarmatian in belgrade surrounndings – in serbian].– 12th congress of the geol. of yugoslia, ohrid, 1, 162–173. preacher, k.j. (2001): april: calculation for the chi-square test: an interactive calculation tool for chi-square tests of goodness of fit and independence [computer software].– available from http://quantpsy.org. rőgl, f. (1998): palaeogeographic considerations for mediterranean and paratethys seaways (oligocene to miocene).– annalen des naturhistorischen museums in wien, 99a, 279–310. rundić, lj. (1992): badenian ostracodes from gornja trnava area, ne bosnia (in serbian and in english).– ann. geol. pennins. balk., 56/1, 251–262. sawyer, j.a. & zuschin, m. (2011): drilling predation in mollusks from the lower and middle miocene of the central paratethys.– palaios, 26, 284–297, doi: 10.2110/ palo.2009.p09-161r schwarzhans, w., bradić, k. & rundić, lj. (2015): fish-otoliths from the marine-brackish water transition of middle miocene strata of belgrade, serbia.– paläontologische zeitschrift, 272, doi: 10.1007/s12542-015-0272-6 stevanović, p. (1951): tragovi panonskog mora u našoj zemlji [traces of the pan­ nonian sea in our country – in serbian].– protection of nature, 2–3, 5–26. stevanović, p. (1970): paleogeografskoekološke prinove iz tortona okoline beograda [paleogeographic and ecological additions from tortonian near belgrade – in serbian].– glas sanu, 258, odelj. prir. mat. nauk., 33, 1–27. stevanović, p. & stepanović, b. (1939): prethodna beleška o drugomediteranskim slojevima na levoj obali topčiderske reke (rakovica) i njihove faune [previous record of the second mediteranian layers on the left bank of the topčider river (ra­ kovica) and their fauna – in serbian].– ann. geol. pennins. balk., 16, 134–136. szczechura, j. & abd-elshafy, e. (1988): ostracodes and foraminifera from? middle miocene of the western coast of the gulf of suez, egypt.– acta palaeontologica polonica, 33/4, 273–342. tomašovych, a. & zuschin, m. (2009): variation in brachiopod preservation along a carbonate shell-basin transact (red sea and gulf of aden): environmental sensitivity of taphofacies.– palaios, 24, 697–716, doi: 10.2110/palo.2009.p09018r vermeij, g.j. (1982): gastropod shell form, repair and breakage in relation to predation by the crap calappa.– malacologica, 23, 329–334. vermeij, g.j. (1987): evolution and escalation: an ecological history of life.– princeton university press, princeton, new jersey, 527 p. vermeij, g.j. (2002): evolution in the consumer age: predators in the history of life.– in: kowalewski, m. & kelley, p.h. (eds.): the fossil record of predation. paleontological special papers, 8, yale university, new haven, 375–394. vermeij, g.j. & dudley, e.c. (1982): shell repair and drilling in some gastropods from the ripley formation (upper cretaceous) of the u.s.a.– cretaceous research 3, 397–403. doi: 10.1016/0195-6671(82)90041-6 vermeij, g.j. & roopnarine, p.d. (2001): edge-drilling history and distribution of a novel method of predation.– paleobios, 21, supplement to number 2, 130. walker, s.e. (2001): paleoecology of gastropods preserved in turbiditic slope deposits from the upper pliocene of ecuador.– palaeogeography, palaeoclimatology, palaeocology, 166, 141–163. doi: 10.1016/s0031-0182(00)00206-6 złotnik, m. (2001): size-related changes in predatory behaviour of naticid gastropods from the middle miocene korytnica clays, poland.– acta palaeontologica polonica, 46, 87–97. zorn, i. (2003): ostracoda from the gaindorf formation (middle miocene, lower bade nian) of mühlbach (molasse basin, lower austria).– annalen des naturhistorischen museum in wien 104 a, 77–84. ab stra ct from palaeozoic (mainly devonian) shallow-water carbonates, spherical to irregular shaped microfossils with thin, apparently homogeneous or perforate micritic walls are widely reported. they are classically referred either to unilocular parathuramminid foraminifera, algae incertae sedis or calcispheres (e.g., bisphaera, cribrosphaeroides, uslo­ nia, vermiporella myna, irregularina). due to their morphology and microstructural features, they are interpreted here as possibly belonging to thaumatoporella pia, a widespread mesozoic-early cenozoic taxon of incertae sedis showing a remarkably high morphological variability. in analogy to mesozoic thaumatoporellaceans, bisphaera ma­ levkensis birina is interpreted as the cyst (i.e.= resting) stage of forms ascribed to different genera, i.e., cribro­ sphaeroides, uslonia and vermiporella (here: vermiporella myna wray). note that in the mesozoic many taxa were also synonymized with thaumatoporella: polygonella elliott, lithoporella elliotti (emberger), messopota­ mella dragastan et al., vermiporella crisiae dragastan et al., micritosphaera scott. this new interpretation, based on material from the devonian of w-germany and the czech republic, leads to taxonomic reassessment as thaumatoporella? malevkensis (birina) nov. comb. as a consequence of our interpretation, the rather long mesozoic to early cenozoic (anisian? to lutetian) record of thaumatoporellaceans is supposed to be significantly larger than formerly assumed. the possible gap of no records of thaumatoporellaceans between the middle carboniferous and the lower triassic cannot substantially be argued at the moment (lazarus effect of one taxon?; two homeomorphic but taxonomically different taxa). keywords: parathuramminida, calcareous algae, incertae sedis, thaumatoporella, bisphaera, cribrosphaeroides, irregularina, uslonia, vermiporella, devonian palaeozoic record of thaumatoporella pia, 1927 (incertae sedis)?  felix schlagintweit1, jindrich hladil2, martin nose3 and carlo salerno4 1 lerchenauerstr. 167, 80935 münchen, germany; (felix.schlagintweit@gmx.de) 2 institute of geology ascr, v. v. i., rozvojová 269, 16500 praha, czech republic; (hladil@gli.cas.cz) 3 snsb-bayerische staatssammlung für paläontologie und geologie, geobiocenterlmu, richard-wagner-str. 10, 80333 münchen, germany; (m.nose@lrz.uni-muenchen.de) 4 lenzhalde 70, 70192 stuttgart, germany; (carlo.salerno@gmx.net) doi: 10.4154/gc.2013.14 1. introduction representatives of the microproblematicum thaumatopo­ rella pia were successful inhabitants of different shallowmarine carbonate environments recorded so far over a very long period, from the middle triassic (ladinian) until the palaeocene (radoičić, 1960; flügel, 1983; de castro, 1990; schmid, 1996). the possible oldest mesozoic record is most likely that from the anisian by emmerich et al. (2005: fig. 14.3, “algal remains similar to thaumato­ porella cf. parvovesiculifera”). later, thaumatoporellaceans were illustrated by nicora et al. (1995: thaumatoporella) also from the lower eocene (illerdian) shallow water limestones drilled at the limalok guyot, southern marshall islands of the central pacific. at this site, they were also observed in younger sediments, up to the middle eocene (lutetian) in age. together with lutetian findings in southern italy (vecchio & barattolo, 2006; vecchio & hottinger, 2007), these represent the youngest records of thaumatoporellacean algae. from the published literature data, a final peak occurrence of thaumatoporellaceans in the lower-middle eocene can be assumed. more important proliferation periods (increased abundance, acme) are concentrated in the early/middle jurassic and late cretaceous time windows. while the jurassic-cretaceous occurrences derive almost exclusively from interto subtidal inner platform fageologia croatica 66/3 155–182 12 figs. 3 tabs. 8 pls. zagreb 2013 geologia croaticageologia croatica geologia croatica 66/3geologia croatica 156 cies, in triassic times, thaumatoporella is also found in re e­ fal carbonates (senowbari­daryan, 1984). however, there are also records of thaumatoporella from late juras­ sic reefal facies (e.g., leinfelder et al., 1993; senow­ bari­daryan et al., 1994; bucur et al., 2005). in the exhaustive work of de castro (1990), thaumatoporel­ laceans were compared with living volvocales and cladopho­ rales and tentatively assigned to the green algae. a possible faunal origin was put up for discussion by flügel (1983). the interpretation of some palaeozoic irregular­shaped to subsphaerical unilocular foraminifera (parathurammin­ ids), and/or algae incertae sedis as thaumatoporellacean al­ gae (in the sense of de castro, 1990) was proposed by vachard (1994) and vachard & clement (1994). these assumptions/interpretations are accepted here and are further corroborated with thin­section material of middle to late devonian shallow­water limestones of the czech re­ public and germany (fig. 1) in comparison to mesozoic ma­ terial. thereby further evidence for the possible presence of thaumatoporellaceans in palaeozoic times is presented. 2. geological setting and material 2.1. czech republic the levels and patches with thaumatoporella­like occurren­ ces were traced in many places across a 15 000 km2 large and, on average, 0.45 km thick segment of middle–upper devonian platform and reef limestones, in the middle and eastern parts of moravia, the se part of the czech republic. about 98 % of these limestones occur in subsurface struc­ tures but were densely drilled and documented during the oil survey works of the second half of the 20th century (e.g., zu­ ka lová, 1981; hladil, 1994; geršl & hladil, 2004; hladil, 2007a; bábek et al., 2007). the platform is dominated by shallow-water facies (reefs with flats and extensive lagoons dominated by amphipora), whilst the rim of slope facies is fragmentarily preserved (hladil, 2002; bosák et al., 2002). the basement compartments with deep ly dissected neoproterozoic and early cambrian rocks belong to a collage of southernmost brunovistulian terrane fragments (kalvoda et al., 2008). the occurrences of thaumatoporella­like fossil objects and related facies are notable features for the late givetian and middle frasnian (see material below). in this paper, we concentrate on the latter. in the devonian of moravia, the “bisphaera”­, “cri­ bro sphaeroides”­, “irregularina”­ and “vermiporella”­ shap ed forms occur together, often in gently inclined aprons around sediment­starved, variously deteriorated intertidal reef flats. they are typically embedded in poorly washed packstones­grainstones with microsparitic clusters, interbed­ ded micrite and occasionally co­occurring large parathuram­ mina. 2.2. germany samples from the middle devonian of germany with thaumatoporella­like microfossils were acquired from shal­ low water platform carbonate sections of various localities within the eifel hills. the limestone synclines of the eifel hills are part of the western rhenish slate mountains, within the rhenohercynian fold­thrust belt of the european varis­ cides. synclines are situated in a n­s trending, approx. 50 km wide, major depression of the eifel nappe, the so­called eifel north­south zone (oncken & weber, 1995; on­ cken et al., 2000; franke, 2000). the eifel north­south zone covers mainly the lower and middle parts of the devo­ nian sedimentary record of the ardennes­eifel shelf, devel­ oped at the southern margin of the old red continent. in this succession, the lower emsian siliciclastics are possibly the oldest known (belka & narkiewicz, 2008, p. 393). these molasse­like sediments are up to several kilometres thick and the transition to carbonate beds is in the upper emsian heisdorf formation. carbonates containing a diverse reef-building fauna first occurred during the early eifelian, followed by the widespread and intensive transgressive de­ velopment of shallow water reef­bearing carbonates of early to middle givetian ages. the late givetian to early fras­ nian platform is partly dolomitized. the middle frasnian has diverse facies, but argillaceous and black shales prevail in the youngest known parts of the succession (late frasnian and early famennian). general large scale palaeogeographical models for the devonian of the rhenohercynian belt in central europe as­ sume that shelf zonation parallels the sw­ne trending south­ ern margin of the old red continent (krebs, 1974; bur­ chette, 1981). the emsian–givetian shelf and platform configuration in the context of the eifel hills is still debated, but a ramp configuration with a southward deepening trend is most likely, based on detailed facies studies (e.g., ute­ scher, 1992; salerno, 2008), though different models exist with postulated structural highs controlling platform development and resulting in a e­w shelf zonation pattern (struve, 1963; faber et al., 1977). figure 1: map of germany and the czech republic with the sample loca­ lites: sötenich, hillesheim and ochoz (stars). schlagintweit et al.: palaeozoic record of thaumatoporella pia, 1927 (incertae sedis)? geologia croatica 157 in terms of environmental distribution, “cribrosphaer­ oides­”, “vermiporella­”, “bisphaera”-shaped forms occur in shallow marine, peritidal and shallow subtidal facies types including massive stromatoporoid, branching stromatoporoid (amphipora) and rugose/tabulate coral biostromes and meadows. the devonian examples studied herein point to an ecological preference of thaumatoporellid-like microfossils for fully marine environmental conditions, though they also occur in marginal marine euryhaline settings (e.g., flügel & hötzl, 1971; salerno, 1997; kaldun, 1998; willmer, 1998). 2.3. material czech republic. – based upon various studies during the last four decades from the moravian segment, we can infer that the thaumatoporella-like facies are not very common here, being found in less than 1 % of the cases. this ratio clearly indicates that the relevant occurrences correspond to specific rather than common environments. for this study, the main focus is on the material from the ochoz skalka quarry situated in the southern part of the moravian karst area (coordinates 49 15 56 n, 16 44 30 e). here, thin sections between 4 and 6 m of the measured section (nos. och 301 – 304, 250 – 254 and 223 – 227) represent rocks of the earliest middle frasnian and others, between 15 and 21 m (nos. och 221, 223, 230, 231, 234, 290, 292 and 293) represent the middle frasnian, around and above the ~pa. punctata / pa. hassi conodont zone boundary equivalent (hla dil et al., 2009). the comparative material referred to in the study is from several other sites, e.g., the youngest occurrences of middle/ upper frasnian age can be exemplified by those in the mokrá central quarry (49 13 46 n, 16 45 29 e; neptunian dykes; thin section nos. jh 1659 and 1660), or the oldest occurrence in the latest middle givetian has been recorded in the ostravice np-824 well (49 33 25 n, 18 22 44 e; depth 1890 m; no. jh 2236 / 31814–g) (zukalová, 2004). the latter paper indicates several levels with thaumatoporella-like fossils in the jablůnka-1 well (49 22 21 n, 17 57 03 e) showing that there is repeated onset and cessation of the related facies in the middle frasnian. germany. – samples studied herein stem from (a) the uppermost eifelian of the hillesheim syncline, (in an abandoned railway cut at nohn mill between the villages of üxheim and niederehe, the middle part of the section, in the so-called katzenley railway cut, lower ahbach-formation, sample numbers k 39, k 41b, k 42, k44b, k 56, cf. kaldun, 1998), (b) the lower givetian of the hillesheim syncline (“cisterziensis marble quarry”, located between the villages of kerpen and niederehe, rodert-formation, sample no. sh 2/2, cf. willmer, 1998); “meerbüsch quarry” between the villages kerpen and üxheim, dreimühlen-formation, sample number mp 2/3; cf. fischer, 1999), (c) the lower givetian of the sötenich syncline (“scheidberg quarry” south of sötenich village, urft river valley, rodert-formation, sample nos. sb 9, sb 15, sb 16; “winter & weiss quarry” south of the village sötenich, loogh-/cürten-formation, sample nos. b 14, 524, cf. salerno, 1997) and (d) the lower givetian of the dollendorf syncline (a quarry at the abandoned railway station of dollendorf, “klotzige bankkalke”, ?dreimühlen-formation, sample numbers kbk 68, kbk 68-1, kbk 69; cf. schröder & salerno, 2001). 3. micropaleontology 3.1. historical review and systematics of mesozoic to early cenozoic thaumatoporellaceans in 1922, raineri described the new species gyroporella parvovesiculifera from the upper cretaceous of southern italy and attributed it to dasycladalean algae. in 1927, pia recognized the differences between raineri´s taxon with gyroporella and introduced the new genus thaumatoporella with the new combination thaumatoporella parvovesicu­ lifera maintaining its assignment to the dasycladalean algae. for the genus diagnosis given by pia see table 1. in 1938, pia studied upper cretaceous material from naxos island, greece, and remarked that thaumatoporella parvovesicu­ lifera represents a “curious” (merkwürdiges) fossil and “that the morphology........is such a bizarre one that i became completely crazy about its interpretation as a dasycladale” (op. cit., p. 492-493, translated from german). as a peculiarity of the genus thaumatoporella, pia didn´t refer to the internal structure but to the general “thallus” morphology that is mostly not regular (e.g., cylindrical) but irregularly bent with branching and highly changing thickness. therefore, pia assumed that the thalli were not growing in an upright position as do dasycladalean algae but was creeping (“kriechend”) on the sea floor. it is also worth mentioning that pia stressed the high variability concerning both morphology and dimensions (e.g., width of “thallus”, pore diameter, wall thickness). identical microfossils were described several decades later from upper jurassic to upper cretaceous shallow-water limestones as polygonella incrustata (elliott, 1957: upper jurassic of the middle east; johnson, 1965: upper cretaceous of greece), lithoporella elliotti (ember ger, 1957: upper jurassic of algeria), polygonella shikoku en sis (imaizumi, 1965: upper jurassic of japan), thaumato­ porella (polygonella) occidentalis (johnson & kas ka, 1965: upper cretaceous of guatemala), messopotamella an­ gulata (dragastan et al., 1985: upper triassic of greece) and vermiporella crisiae (dragastan et al., 1989: upper aptian of romania). these forms were mainly interpreted as red algae (corallinaceae, solenoporaceae) or algae incertae sedis differing from t. parvovesiculifera by differences in “cell” (= pore) dimensions, e.g., “shor ter and wider cells” in t. occidentalis, morphology etc. there seems to be a general consensus in the literature, however, that these parameters are highly variable (following pia, 1938) and that therefore these forms should be included in the variability of thaumatoporella parvovesiculifera (raineri), thus representing junior synonyms (sartoni & crescenti, 1959; radoičić, 1960; fenninger & hötzl, 1967; flügel, 1983; de castro, 1990, 1991; düzbastilar, 1991; schlagintweit, 1992). this represents the widely accepted concept of polymorphic thaumatoporellaceans (fig. 2). one of the oldest detailed studies was conducted by sartoni & crescenti (1959) based on geologia croatica 66/3geologia croatica 158 liassic specimens. contrasting their material with that from the upper cretaceous type material, sartoni & crescenti (1959: p. 130) stated that it is impossible to distinguish between both, specifically due to intermediate gradations in dimensions, therefore indicating a rather long stratigraphic range for thaumatoporella parvovesiculifera. nevertheless, the authors mentioned a pure statistical difference, namely the occurrence of larger values (wall thickness, pore diameter) for the upper cretaceous forms. a detailed morphological description and analysis of thaumatoporellaceans was presented by de castro (1988, 1990, 1991). besides new interpretations on internal structures, the order thaumatoporellales and the family thaumatoporellaceae were introduced by de castro (1988) (tab. 1). however, an emendation of the genus diagnosis of pia (1927) was not presented. concerning the systematics of thaumatoporellaceans, de castro (1990, p. 204, translated from italian) concluded that it is “probable that within the middle triassic to palaeocene period more species and more genera of thaumatoporellaceans existed. however, the considerable intergradations of the morphological features, the great variability of the wall thickness in homeomorphic specimens.....make the distinction of different species very difficult at the present state of knowledge”. the high morphological (e.g., shape, dimensions) variability of thaumatoporella is here exemplified from late sinemurian specimens of albania (pl. 1). 3.2. morphology of mesozoic thaumatoporellaceans the general morphology of thaumatoporellaceans does not correspond to a fixed bauplan but is highly variable including completely different morphotypes: irregular lobate, globose, ovoid, and more or less cylindrical shapes. deeply constricted “thalli” (de castro, 1990: “deep invaginations”) may display a chambered appearance due to the outer wall protruding into the interior. according to de castro (1990, p. 186), it cannot be excluded that these structures are connected to “reproduction phenomena”. thaumatoporellaceans can be free-living, attached to hard substrates, dwell as cryptoendoliths inside hollow bioclasts (see schlagintweit & velić, 2012) or dwell within microbial crusts (schlagintweit, 2013) (pl. 1). some of these modes of life are controversial and not fully understood with respect to possible life cycles or adaptations to different environmental conditions. for irregular-shaped morphotypes with elongated protuberances, reported from liassic peritidal carbonates, a psammobiontic way of life was recently discussed (schlagintweit et al., 2013) in an analogy to the palaeozoic irregularina (vachard, 1994) (fig. 3). in this connection, it is noteworthy that vachard (1994, p. 31) argues that irregularina, due to its assumed psammobiontic way of life, may be the deformed stage of a microfossil whose free (= non-psammobiontic) stage is represented by bisphaera. thaumatoporellaceans consist of an outer perforated micritic wall enclosing an internal cavity preserved as sparry calcite. in fixed specimens, the base is mostly thinner (flü­ gel, 1983; de castro, 1990: “strato rudimentale”; schlagintweit, 2012). internal structures typically with thinner walls than the enclosing one were interpreted as daughtercolonies (de castro, 1988, 1990), thus implying an algal origin, or ontogenetic stages of an animal (flügel, 1983). in some specimens, there are several stacked structures like a nested russian doll (matryoshka) (see pl. 1a). leaving these interpretations open, they are neutrally referred to here as “internal bodies”. spheroidal morphotypes or morphotypes with a very thin wall seem to be non-perforate (or have pores that are not discernible?). as previously remarked by figure 2: a: cribrosphaeroides permirus (antropov), modified from chuvashov (1965: pl. 3, fig. 7 upper frasnian of russia). b: micritosphaera ovalis scott, modified from scott (1978: fig. 1g, albian of guatemala; no scale was indicated). both forms are interpreted here as thaumatoporellaceans. dc = structures called daughter-colonies by de castro (1990). table 1: diagnosis of thaumatoporella and suprageneric classification referring to an algal origin (pia, 1927; de castro, 1988). de castro (1988, p. 249) order thaumatoporellales benthic colonies, internally void, formed by a sheath layer at the periphery of the colonial cavity. each sheath contains a single cell or a succession of cells. the vegetative reproduction leads to the formation of autocolonies. de castro (1988, p. 249) family thaumatoporellaceae colonies, presenting a more or less regular form, constituted of cells or filaments of variable length inside of sheats laterally joined to form a well defined “sheat-layer”. the sheats, all perpendicular to the layer which they generate, are tightly joined among themselves and consequently form a polygonally shaped network in the belt sections of the layer. the sheats are simply or dichotomously branched. the sheat layer shows a various arrangement; in any case it delimits a colonial cavity completely occluded. it shows a variable number of openings, more or less pronounced and funnel shaped, with the wider part towards the internal cavity of the colony. a single colony may contain in its cavity one, two or three generations of daughter-colonies (autocolonies) of variable size, and of the same or different shape; the shape can be the same or different from the parent. within the colony we can find daughter-colonies lacking a cavity, with sheats distributed according to open surfaces of variable form. pia (1927, p. 69, translated from german) genus thaumatoporella in general, morphology and disposition of pores (“äste”) compares to triassic macroporellas. the shape of the thallus and the main axis though is very irregular, ramifying and bending. this recalls dasyporellas. however, a direct connection to these is unlikely. the genus may in fact go back to macroporella. schlagintweit et al.: palaeozoic record of thaumatoporella pia, 1927 (incertae sedis)? geologia croatica 159 plate i examples for the way of life of mesozoic thaumatoporellaceans (t). a specimens showing different life strategies: free in the micritic matrix (1), epilithic, attaching to microbial crusts that envelope a gastropod shell (2) and thus likely documenting a post-mortem colonization, and cryptoendolithically inside the inner whorls of the shell (3). pliensbachian of mount biokovo, croatia, thin-section ve 514-13 (see gusič, 1977). b specimens inside rudist shell of praeradiolites acutilamellosus. some are attached to the inner side of the rudist shell others are dispersed in the micritic filling. cenomanian of northern italy (modified from caffau et al. 1996: pl. 7, fig. 1). note the sponge borings (ichnogenus entobia) parallel to the shell surface (upper side). pia (1938), both the wall thickness and the dimensions of the pores (or alveoli) are highly variable (for details see section 3.4). in general, the polymorphism of thaumatoporella pia and the resulting taxonomic splitting in the past is widely accepted among (mesozoic) micropaleontologists (tab. 2). this concept is now applied here to a variety of problematic palaeozoic “foraminifera” and “algae” (figs. 2–3, tab. 2). 3.3. generic interpretation of the palaeozoic forms the priority concept of the linnean taxonomic system is it´s independence from the biological origin (plant or animal) of a taxon in question, and that it is mandatory for names below the rank of family (icbn art. 11). it refers to the oldest available name as the valid name of a taxon (iczm art. 23). in the present case study different taxa (in order of publication date) are considered: geologia croatica 66/3geologia croatica 160 • vermiporella stolley, 1893 (introduced as an alga) • thaumatoporella pia, 1927 (introduced as an alga) • bisphaera birina, 1948a (introduced as a foraminifer) • irregularina bykova, 1955 (introduced as a fora minifer) • uslonia antropov, 1959 (introduced as a foraminifer) • cribrosphaeroides reitlinger, 1959 (introduced as a foraminifer) vermiporella was described as a dasycladalean alga by stolley (1893) from ordovician-silurian erratic boulders of the baltic coast, as having bent and branching tubes with simple pores, either perpendicular or slightly inclined to the axis. based on silicified and three-dimensionally preserved thalli from ordovician boulders of the baltic coast, a revised diagnosis was given by kozlowski & kaźmierczak (1968), showing that the structure of vermiporella is “fundamentally different from that previously described by various authors” to this genus. the alga is characterized by dichotomously branching (in various planes), and anasto mosing tubes, giving rise to a three-dimensional bush-like thallus structure, “forming a sort of a tangled network or lattice” (kozlowski & kaźmierczak, 1968: p 331). inside the tubes, a central stem that occupies about 1/3 of the diameter occurs, displaying regular contractions. attached to the stem, three orders of lateral branches are present forming regular whorls. in addition, sporadic septae and spores of the type of oospores occur in the central stem. concerning the taxonomic position, kozlowski & kaźmierczak (1968) stress the mixed character, partly including features of dasycladalean (e.g., regular arranged branches) and ulotrichalean algae. concerning “vermiporella myna” (here considered a possible representative of the genus thaumat­ oporella), the light-sparitic thick-walled appearance of representatives of vermiporella, e.g., v. canadensis johnson, 1970 is striking. this difference in the wall microstructure (aragonitic in vermiporella) between both was previously stressed by vachard (1994, p. 37). in the decades following the introduction of some of the listed taxa, they were controversially discussed including the proposal of synonymies and new combinations, and some were renamed: • cribrosphaera was renamed as cribrosphaeroides by reitlinger (in rauzer-chernousova & fur senko, 1959). • chuvashov (1965) proposed the new combination cribrosphaeroides permirus (antropov) by assuming the synonymy of uslonia with cribrosphaeroides. figure 3: variability of mesozoic thaumatoporella pia (a-e) and application/transfer of this concept to a variety of palaeozoic (devonian) parathuramminid foraminifera-algae incertae sedis (f-j). without scales. mesozoic examples: liassic of albania (a, d-e) and italy (c); cenomanian of serbia (b). palaeozoic examples: devonian of germany (f-g, i), luxembourg (h, from bouckaert et al., 1977: pl. 3, fig. 57), and russia (from chuvashov, 1965: pl. 3, fig. 4). table 2: taxonomic concept of mesozoic to early cenozoic thaumatoporella (e.g., sartoni & crescenti, 1959; radoičić, 1960; flügel; 1983; de castro, 1990) confronted with possible palaeozoic representatives. mesozoic paleozoic polygonella elliott, 1957 lithoporella elliotti emberger, 1957 messopotamella dragastan et al., 1985 vermiporella crisiae dragastan et al., 1989 micritosphaera scott, 1978 bisphaera birina, 1948 ? irregularina bykova, 1959 cribrosphaeroides reitlinger, 1959 uslonia antropov, 1959 vermiporella myna wray, 1967 schlagintweit et al.: palaeozoic record of thaumatoporella pia, 1927 (incertae sedis)? geologia croatica 161 • bisphaera, irregularina, and cribrosphaeroides were included in the family irregularinidae by zadorozhnyy & yuferev (1984) (see also vachard, 1994) showing their inferred systematic relationships. • vachard (1994: p. 38) transfered vermiporella my­ na wray to the genus cribrosphaeroides, a view followed by mamet et al. (1999). other authors, however, did not adopt this proposal (feng et al., 2010). • uslonia permira was interpreted by vachard (1994: p. 29) as non-biogenic, corresponding to “large and irregular sparitic debris” namely cortoids. • vachard (1994: fig. 15) illustrated continuous morphological transitions between bisphaera birina, 1948 and irregularina vissarionova, 1950, however without treating the latter as a synonym of the former. • mamet & préat (2009) treated vermiporella myna as a synonym of uslonia permira antropov, thus rejecting the cortoid interpretation of vachard (1994). • afanasieva & amon (2011) considered bis pha­ era as representing a radiolarian assigned to the genus trochodiscus haeckel, 1887, thereby introducing the new combination trochodiscus malevkensis (birina, 1948). the aspect of a possible radiolarian nature of some parathuramminids (e.g., bisphaera) was also envisaged by vishnevskaya & sedaeva (2002). it is worth mentioning that bykova (1955: p. 15) also treated bisphaera as a pelagic form, due to its spheroidal shape and the primitiveness of its structure. further discussion of these issues is not necessary as they are not accepted here. the different taxonomic combinations (also introduced by outstanding experts in palaeozoic microfossils and to our knowledge without studying the russian type-material) clearly expressing the continuing uncertainty. this is also evident from the differing interpretations concerning the biogenic nature, from unilocular foraminifera, algae (algae in­ certae sedis, dasycladales, thaumatoporellaceans sensu de castro), microproblematicum, and non-biogenic in the case of uslonia (see tab. 3). here we pick up again the idea (or hypothesis) already expressed by vachard & clement (1993, p. 301, translated): “in conclusion it might therefore be appropriate to add false palaeozoic foraminifera, bisphaera and cribrosphaeroides, to the mesozoic thaumatoporellales” (although before, e.g., vachard, 1991 and later again, e.g., vachard et al., 2010, bisphaera was considered as representing a unilocular foraminifer). shortly afterwards, this view was further specified by vachard (1994, p. 34) as follows: “the genus cribrosphaeroides is morphologically closest to thaumatoporella, and daughter-colonies seem to be figured by chuvashov (1965)”. to comprehend this hypothesis, it is re-illustrated here and compared to similar internal structures observed from cretaceous “micritosphaera” (scott, 1978) (fig. 2). excluding the genus vermiporella, thaumatoporella represents thus the oldest available name for the group of bi­ sphaera-cribrosphaeroides-type microfossils that, due to their appearance as various morphotypes, were ascribed to different genera (see discussion) (see fig. 3). this conclusion follows the interpretation of bisphaera as a cyst stage of a possible thaumatoporella species (pl. 3). concerning the stratigraphy reported to date in the literature, only slightly diftable 3: different views of the nature (biogenic/abiogenic) of the group bisphaera-cribrosphaeroides-uslonia-vermiporella myna according to literature data supplemented by our new interpretation. bisphaera birina cribrosphaeroides reitlinger uslonia antropov vermiporella myna wray unilocular foraminifer (birina, 1948; flügel & hötzl, 1971; loeblich & tappan, 1987; vachard, 1991; edgell, 2004; vachard et al., 2010) incertae sedis (toomey & mamet, 1979) thaumatoporellacean alga (vachard & clement, 1993) free stage of a psammobiontic, deformed taxon, namely irregularina (vachard, 1994) radiolaria, namely trochodiscus haeckel (afanasieva & amon, 2011) unilocular foraminifer (reitlinger, 1959; flügel & hötzl, 1971; loeblich & tappan, 1987; vachard, 1991; may, 1994) alga (toomey & mamet,1979) thaumatoporellacean alga (vachard, 1994) unilocular foraminifer (antropov, 1959; loeblich & tappan, 1987) incertae sedis (toomey & mamet, 1979) non-biogenic, irregular sparitic debris (cortoids) (vachard, 1994) dasycladale alga (wray, 1967; flügel & hötzl, 1971) ulvophycean alga (feng et al., 2010) thaumatoporellacean alga (vachard, 1994: cribrosphaeroides myna) this work free cyst stage of a thaumatoporellacean (incertae sedis), possibly thaumatoporella pia thaumatoporellacean (incertae sedis), possibly thaumatoporella pia geologia croatica 66/3geologia croatica 162 plate ii morphological variability of thaumatoporella parvovesiculifera (raineri) from the liassic (late sinemurian) of albania (a-d, f, h), lower cretaceous (aptian) of italy (e), middle jurassic (late aalenian) (g) and the upper cretaceous (coniacian) of slovenia (i) and croatia (j). a thaumatoporellaceans as microfacies dominating biogens. note the nesting doll-like “bodies” placed one inside the others (daughter-colonies sensu de castro, 1988 or ontogenetic stages sensu flügel, 1983). rhapsha-tamara, nw-albania, thin-section a 3639. b tube-like morphotype with a handle (left) and constriction (right). note the thin-walled internal “body” (compare to a). rhapsha-tamara, nw-albania, thin-section a 3639. c irregular-shaped morphotype exhibiting thin walls, interpreted as psammobiontic forms winnowed from a packstone (see remains of original matrix around the two specimens in the centre). rhapsha-tamara, nw-albania, thin-section a 3644. d, f irregular rounded specimens exhibiting constrictions. this morphotype compares to specimens of the palaeozoic bisphaera. rhapsha-tamara, nwalbania, thin-section a 3639. e same as d and f. note the inner fibrous calcitic layer (arrows). aptian of sorrento peninsula, s-italy (see raspini, 2011). g spherical morphotype exhibiting a thin wall without detectable pores. this morphotype compares to specimens of the palaeozoic bisphaera. mount biokovo, croatia, thin-section bst 8-1. h specimens with internal “bodies” (compare to a). note that the latter display thinner walls and completely mimic the shape of the external wall (specimen above). rhapsha-tamara, nw-albania, thin-section a 3639. i grainstone with benthic foraminifera (mainly miliolids) and variously-shaped thaumatoporellaceans: cylindrical, lobate to bizarre-shaped (“irregularina”-type, circles) and globose (“bisphaera”-type, b). coniacian-santonian of sw slovenia (see jež et al., 2011: fig. 7d). j thick-walled specimens (thaumatoporella wackestone). coniacian of mljet island, croatia. thin-section mrs 3-1. scale bars 1 mm for a-d, h-i; 0.5 mm for e-g, j. schlagintweit et al.: palaeozoic record of thaumatoporella pia, 1927 (incertae sedis)? geologia croatica 163 plate iii spheroidal thaumatoporellaceans interpreted as cyst stages: thaumatoporella parvovesiculifera (rainer) (a-n) and thaumatoporella? malevkensis (birina) nov. comb. (m-q). a pliensbachian of croatia, thin-section ve 514-2 (leg. i. gusič). b pliensbachian of croatia, thin-section ve 514-3 (leg. i. gusič). c late aalenian-early bajocian of croatia, thin-section bst 8-1 (leg. i. velić). d-e note the slight constriction (arrow). compare with example (m). late aalenian-early bajocian of croatia, thin-section sl 4a (leg. i. velić). f late aalenian-early bajocian of croatia, thin-section sl 5b (leg. i. velić). g late aptian of italy. note the inner inner fibrous layer (arrow) (leg. a. raspini). h-i late cenomanian of serbia, thin-section rr 6145 (leg. r. radoičić). j-k modified from scott (1978: fig. 1a and 1d), figured as micritosphaera ovalis. note the wall interruption (interpreted as aperture in the original description) in (arrow in 10) and the outer cement fringe in (arrow in 11). thin-sections 9015-19 and 9019-19. l norian-rhaetian of austria, thin-section ok w 530-1 (leg. o. krische). m “bisphaera variabilis” conil & lys, modified from edgell (2004: pl. 1, fig. 1); devonian of australia. note the slight constriction (arrow). n devonian of czech republic, thin-section hl 234. o devonian of czech republic, thin-section hl 259. p devonian of germany, thin-section k 41. q devonian of germany, thin-section k 44. scale bars 0.3 mm. geologia croatica 66/3geologia croatica 164 fering ranges have been defined and these can therefore not be considered as a strong argument against this interpretation. bisphaera: early devonian (vachard, 1994) up to the upper part of the tournaisian (reitlinger et al., 1996; kulagina, 2013) [but with the possibility of emerging since the late ordovician (cf. the thin sectioned objects from uggwa limestone, carnic alps – kreutzer, 1992, pl. 3, fig. 4); or even early ordovician (sabirov & gushchin, 2006, tajikistan) though the latter was considered dubious by vachard et al., 2010, p. 220]. irregularina: givetian – tournaisian (vachard, 1994) [possibly from silurian–devonian (juyal et al., 2009, determined by i. premoli silva) and also ordovician (kreutzer, op. et loc. cit., figured)]. cribrosphaeroides: givetian (vachard, 1994) up to the upper part of the tournaisian (kulagina, 2013) [possib ly silurian–devonian (juyal et al., op. cit.), and, pos sib ly since the late ordovician (bykova, 1961, kazakhstan)]. however, one must be aware that shifts in these ranges are always possible bearing in mind the evolving knowledge base on the stratigraphic distribution of mesozoic thaumat­ oporella as indicated in the introduction of this paper. concerning the genus irregularina bykova, 1955, the possible transfer to thaumatoporellacens is problematic as no “internal bodies” (= daughter-colonies sensu de castro) or perforations in the wall were observed in our material (see schlagintweit et al., 2013, for details) (fig. 4a). the morphology, however, is well known from mesozoic thau­ matoporella (schlagintweit et al., 2013, for details) including forms with (fig. 4b) and without detectable pores (fig. 4c). it is worth mentioning that irregularina longa described by konoplina (1959) is said to possess a perforated wall. in fact, this form most likely corresponds to irregular tubiform morphotypes of the species described as vermiporella myna by wray (1967) (see details in the discussion) (e.g., pl. 4m). further remarks on all aspects and interpretations are given in “remarks and discussion” below the systematic description. 3.4. systematic micropaleontology the suprageneric taxonomy used here partly follows the suggestion of de castro (1988, 1990). while accepting the family name, however, we consider the algal nature as doubtful. incertae sedis family thaumatoporellaceae de castro, 1988 genus thaumatoporella pia, 1927 (assumed) synonyms: bisphaera birina, cribro­ spha e ro ides reitlinger, ? irregularina bykova, us­ lonia antropov. thaumatoporella? malevkensis (birina, 1948) nov. comb. (fig. 4a?, fig. 5, fig. 6a, figs. 7a–b, pl. 3m–q, pls. 4–8) *1948a. bisphaera malevkensis n. gen., n. sp.– birina, p. 159, pl. 2, fig. 9. 1954. cribrosphaera simplex n. gen., n. sp.– reitlinger, p. 65, pl. 18, fig. 7, pl. 19, figs. 9-10, ? pl. 21, fig. 1 (remark: possibly a fixed specimen). 1959. cribrosphaeroides simplex (reitlinger) – reitlinger in rauzer-chernousova & fursenko, p. 174, fig. 70. 1959. uslonia permira n. gen., n. sp.– antropov, p. 28, pl. 1, figs. 1–2. 1967. vermiporella myna n. sp.– wray, p. 31, text-fig. 12, pl. 6, figs. 6–8, pl. 7, figs. 1–2. description: the devonian specimens display a wide variability with respect to shape, biometric data (size, pore diameter, wall thickness) and wall preservation (figs. 8-9). the shape ranges from spherical, ovoid with or without constrictions, irregular to bent tubes displaying irregular constrictions and swellings. concerning the circular sections (pl. 4f), these may result either from spherical specimens, or represent the transverse sections of tubes. in tangential sections of the wall, a honey-comb-like pattern is discernible (pl. 4c). specimens with a round outline exhibiting more or less equal wall thickness throughout, and poorly detectable pores, can be assigned to spheroidal morphotypes (= bisphaera-type) (fig. 5b, pl. 5d, pl. 8h). such sections may be more or less completely round (pl. 5d), ovoid (pl. 8h), with one to several constrictions (e.g., = type “bisphaera elegans”, pl. 5h). one shallow constriction in a slightly elliptical form may result in a virtual “two-chambered” bipartition along a central symmetry plane (= type “bisphaera malevkensis”, pl. 7d). tubes may be more or less straight (pl. 8c) to slightly curved (pl. 4m, pl. 5b, pl. 7j, pl. 8c) or irregular serpentine to sigmoidally curved (pl. 4l, pl. 8b, d). more rarely specimens show irregular branching or bifurcation (fig. 6a). such figure 4: irregular shaped palaeozoic irregularina (a) and mesozoic thaumatoporellaceans (b-c) assumed to have a psammobiontic way of life (schlagintweit et al., 2013, for details). a irregularina without discernible pores. the laterally arising prolongations were described as “apertural nozzles” of irregularina karlensis vissarionova. givetian of germany, thin-section sb 16. b thaumatoporella exhibiting perforate wall. upper cretaceous (“senonian”) of albania, thin-section kru 1b. c specimen without discernible pores. liassic of albania, thin-section a 3642. schlagintweit et al.: palaeozoic record of thaumatoporella pia, 1927 (incertae sedis)? geologia croatica 165 shapes were illustrated for both “vermiporella myna” (wray, 1967: pl. 6, fig. 7) and “uslonia permira” (antropov, 1959: pl. 1, figs. 1-2). in rare cases, tubes exhibit irregular club-shaped swellings (pl. 7c). the interior of the polymorphic specimens is usually filled with sparry calcite. sometimes, partial damage may have resulted in the intrusion of sediment grains from the surrounding matrix (e.g., pl. 5b). rather common, various shaped “internal bodies” with thin micritic walls, with poorly preserved to non detectable pores, thus appearing imperforate, can be observed. these may be rather small compared to the outer enclosing tube or other morphology, thus seemingly floating in its interior (e.g., pl. 6a). more rarely these structures are comparatively large, almost entirely filling the interior and thus in part closely attached to the surrounding wall (pl. 6e). in execeptional cases, there are several “bodies” stacked one in another (pl. 8e). these structures were previously illustrated from “cribrosphaeroides permirus” by chuvashov (1965) or from “bisphaera sp.” by vachard & clement (1994). they are in our opinion slightly recognizable in the two specimens of “uslonia permira” illustrated in the work of antropov (1959: pl. 1, figs. 1-2). these two specimens resemble the one illustrated here on plate 5j. the wall of thaumatoporella? malevkensis (birina) is composed of dark micrite, appearing either homogeneous (without detectable pores) or transsected by close-set pores that in tangential sections appear as a typical honey-comb pattern (pl. 4c, pl. 7k, pl. 8j). it is common, for a hyaline fibrous outer zone to be present, mostly in bisphaera-type specimens with comparatively thin walls without detectable pores (e.g., pl. 5b, e, i) (compare liassic thaumatoporella specimens in pl. 2d, f-g). another type of preservation is represented by a less dense outer zone (microsparite?) that due to its poorly recognizable pores does not seem to represent a precipitated cement but likewise a part of the former organism wall. such an alteration phenomenon is also reported from mesozoic thaumatoporella (e.g., de castro, 1991, pl. 3, fig. 4). dimensions: (see also figs. 8-9) diameter of (subcircular) sections: 0.28 to 0.55 mm diameter of ovoid sections: up to 0.7 mm maximum length of tubiform morphotype: 2.25 mm thickness of tubiform morphotype: 0.25 to 0.4 mm thickness of wall: 15 to 50 µm diameter of pores: 8 to 31 µm figure 5: “two in one” aspect of specimens lacking visible pores in the lower part (genus “bisphaera”) and displaying a perforate wall in the upper part (genus “cribrosphaeroides”). the lobate outline may be present in both “bisphaera” (or deeply multilobate in irregularina) and “cribropshaeroides”. a) thinsection k 39 b) k 56. devonian (upper eifelian) of the hillesheim syncline, germany. scale bars 0.2 mm. figure 6: “branching” specimens of thaumatoporella. a) thaumatoporella? malevkensis (birina) nov. comb., middle-upper givetian of ostravice np-824 well, czech republic (see zukalova, 2004: vermiporella sp., pl. 13, fig. 3). b) thaumatoporella parvovesiculifera (raineri), upper cretaceous (coniaciancampanian interval) of south italy (see checconi et al., 2008: pl. 1, fig. 18). geologia croatica 66/3geologia croatica 166 remarks: from the pore diameters given in the literature, the range of “uslonia permira”-“cribrosphaeroides myna” is well present in thaumatoporella parvovesiculifera but the latter also comprises specimens with distinctly greater values (fig. 8). in contrast, also at the lower end of pore range, the devonian representatives often exhibit smaller diameters. an equivalent observation is obtained from the wall thickness comparing palaeozoic and mesozoic forms (fig. 9). again, the measurements of the palaeozoic forms correspond well with mesozoic thaumatoporella but the latter also exhibits distinctly thicker walls (or “cell length” in the older literature, e.g., johnson & kaska, 1965). the highly evolved late cretaceous representatives of thaumat­ oporella parvovesiculifera may reach wall thicknesses of up to 230 µm as measured from de castro (1990, pl. 4, fig. 3) (see pl. 2j). the wall thickness of the liassic assemblages figure 7: attaching specimens of thaumatoporella? malevkensis (birina) nov. comb. (a-b), devonian (famennian) of luxembourg (from conil in bouckaert et al., 1977: pl. 3, figs. 57-58) and thaumatoporella parvovesiculifera (raineri) (c), liassic of italy (modified from de castro, 1997: pl. 24, fig. 1). arrows in b indicate the attached side. the liassic specimen attaches to the main axis of the dasycladale palaeodasycladus mediterraneus pia (p). note the basal protrusion (arrow). morphologically, these palaeozoic and mesozoic forms cannot be distinguished from each other (details in the text). figure 8: pore diameter (in µm) of thaumatoporella? malevkensis (birina) nov. comb. (1-10) against thaumatoporella parvovesiculifera (pia) (11-16). 1-4 for cribrosphaeroides simplex, 5 for uslonia permira 6-9 for vermiporella myna. 1: reitlinger (1954) 2: chuvashov (1965) 3: poyarkov (1969) 4: vachard (1994) 5: antropov (1959) 6: flügel & hötzl (1971) 7: may (1994) 8: wray (1967) 9: toomey et al. (1970) 10: this work, givetian-frasnian of germany and czech republik 11: pia (1938, upper cretaceous of greece) 12: imaizumi (1965, upper jurassic of japan) 13: sartoni & crescenti (1959, liassic and upper cretaceous of italy) 14: flügel (1983, upper triassic of greece) 15: johnson & kaska (1965, upper cretaceous of guatemala) 16: this work, liassic (late sinemurian) of albania. schlagintweit et al.: palaeozoic record of thaumatoporella pia, 1927 (incertae sedis)? geologia croatica 167 plate iv thaumatoporella? malevkensis (birina) nov. comb. from the devonian (upper eifelian) of the hillesheim syncline, eifel hills, germany. a oblique section showing pores on the left side. thin-section k 39. b-c tangential sections showing honey-comb-like pore pattern. thin-section k 39. d-e slightly lobate thalli with barely visible pores, e.g., right below in e. thin-section k 39. f-g,i transverse sections of spherical or cylindrical thalli showing perforate wall. thin-section k 39. j-k lobate specimens with (j) and without visible pores (k). thin-sections k 39 and k 41b. l longitudinal section of an irregular bended tubiform thallus with well discernible pores. thin-section k 41b. m longitudinal section of a slightly bended tubiform thallus. note the yellowish calcitic inner and outer rim (arrows). thin-section k 39. scale bars 0.25 mm shown in plate 2a-h, ranges from ~15 to 160 µm, the pore diameters from ~8 to 40 µm. the extreme upper values of the mesozoic forms, never reached even roughly by the palaeozoic specimens, is here taken as evidence that we are dealing with two different taxa, interpreted as specific characteristics: thaumatoporella? malevkensis (birina) nov. comb. and thaumatoporella parvovesiculifera (raineri). the wide range of pore diameter on the other hand, cannot be taken as a clearly defined criterion to separate “coarsely perforate” forms like “cribrosphaeroides” from finely perforate forms such as some specimens of “bisphaera”. furthermore it can be stated that the overall morphological variability of the devonian specimens is slightly reduced compared to thaumatoporella parvovesiculifera (raineri), such as the lack of highly constricted, partitioned morphotypes in the latter. geologia croatica 66/3geologia croatica 168 plate v thaumatoporella? malevkensis (birina) nov. comb. from the upper eifelian to lower givetian of the hillesheim and sötenich synclines, eifel hills, germany. a irregular tubiform thallus. thin-section k 56. b ovoid-lobate specimen without discernible pores (typus “bisphaera grandis-elegans”, left above, see also fig. 4a) and irregular cylindrical specimen showing perforate wall. both exhibit a thin outer cement crust (white arrows). partial breakage of the wall (black arrow) may have resulted in the intrusion of sediment grains of the surrounding matrix.thin-section k41b. c ovoid specimen showing slightly lobate appearance (on the left, typus bisphaera) and partly with visible pores (arrows). thin-section k 56. d almost circular section with thin wall. pores are not visible. thin-section k 44b. e lobate specimen with visible pores (arrows). thin-section k 56. f circular sections with pores (arrow). thin-section k 44b. g-h lobate morphotypes (type “bisphaera malevkensis”), partly with visible pores (arrow in h). thin-sections k 56, k 41b. i lobate form with a deep-reaching constriction (above) and partly visible pores (arrow). note the rather thick outer rim of yellowish calcite. thin-section k44b. j irregular tubiform morphotype with “internal body” (ib). thin-section sb 15. k-l oblique sections. thin-section k 39 and mp 2/3. scale bars 0.2 mm for a, c-l, 0.5 mm for b schlagintweit et al.: palaeozoic record of thaumatoporella pia, 1927 (incertae sedis)? geologia croatica 169 plate vi thaumatoporella? malevkensis (birina) nov. comb. from the upper eifelian to givetian of the hillesheim and sötenich synclines, eifel hills, germany. a-g different sections of specimens exhibiting internal “bodies”. these may be of similar (e.g., a, f ) or different shape (e.g., c, e) than the external outline. thin-sections k 39 (a, e), k 42 (b), k 56 (c-d), sh2-2 (f ) and sb 16 (g). h irregular club-shaped specimen. thin-section sb 15. i-j irregular lobate specimen showing pores and outer calcitic rim in i. thin-sections sb 16 and sb 9. k multilobate specimen with obliterated and barely visible wall. thin-section sb 5. l multilobate specimen exhibiting pores. thin-section sb 15. scale bars 0.2 mm for a-f, h-j, l, 0.5 mm for g, k geologia croatica 66/3geologia croatica 170 plate vii thaumatoporella? malevkensis (birina) nov. comb. from the lower givetian of the dollendorf (b, d, e, h, i, k-m) and sötenich (a, c, f-g, j) synclines, germany. a specimen with internal “body” (arrow). thin-section 524. b transverse section of a “cribrosphaeroides”-type finely perforate cylindrical or spheroidal specimen. thin-section kbk 68. c club-shaped specimen (compare liassic specimen on pl. 1, fig. b). thin-section b 14. d kidney-shaped specimen of “bisphaera” type. thin-section kbk 68. e irregular lobate specimens. thin-section kbk 68. f-g lobate specimens exhibiting internal “bodies”. thin-sections b 14 and 524. h irregular lobate to subglobular (right above) specimens. the larger specimen (below) partially shows features of pressure solution (stylolites). thinsection kbk 68-1. i lobate thin-walled and finely perforate “bisphaera”-type specimen on the left side and thicker-walled perforate “cribrosphaeroides”-type specimen on the right. thin-section kbk 68. j irregular cylindrical specimen. thin-section b 14. k various sections of two specimens. thin-section kbk 68. l-m various sections of specimens exhibiting internal “bodies” (arrow). thin-sections kbk 68 and kbk 69. scale bars 0.5 mm, except b, d = 0.3 mm. schlagintweit et al.: palaeozoic record of thaumatoporella pia, 1927 (incertae sedis)? geologia croatica 171 plate viii thaumatoporella? malevkensis (birina) nov. comb. from the frasnian of the skalka quarry near ochoz, czech republic. a specimen showing two appendages. thin-section och 224. b, d, i-k irregular bent “vermiporella myna”-type specimens showing well discernible perforate character of wall. thin-section och 225 (b, d), och 223 (i-k). c cylindrical specimen, length 1.85 mm (compare upper cretaceous thaumatoporella shown in pl. 1, fig. i). note the zonation of the wall with a bright, less dense distal zone with poorly recognizable pores, a phenomen also reported from mesozoic thaumatoporella (e.g., de castro, 1990: pl. 3, fig. 4). thin-section och 234. e specimen showing telescope-like stacked “internal bodies”. compare liassic specimens shown in pl. 1, fig. a. thin-section och 227. f section showing longitudinal (left) and oblique sections of pores (compare text-figure 12 of “vermiporella myna” in wray, 1967). thin-section och 230. g specimen exhibiting semicircular outline and well discernible pores. morphologically it corresponds to “cribrosphaera pertusa” bykova (1961: pl. 22, fig. 10). thin-section och 253. h globular “bisphaera”-type specimen showing thin wall with fines pores only dimly recognizable in some parts. thin-section och 227. scale bars 0.5 mm, except e = 0.3 mm. geologia croatica 66/3geologia croatica 172 the assumed cyst stages of both thaumatoporella? ma­ levkensis (birina) nov. comb. and thaumatoporella par­ vovesiculifera (raineri) cannot be distinguished, neither on aspects of morphology, size, wall thickness nor preservational modes (pl. 3). referring to the middle devonian (eifelian) to early carboniferous (tournaisian) occurrences of thaumatopore­ lla? malevkensis (reitlinger), the huge gap of roughly more than 100 my until the appearance of thaumatoporella parvovesiculifera (pia) in the middle triassic can also be taken as evidence that these are different taxa. alternatively, our data are currently insufficient to provide a comprehensible explanation, whether we are dealing with a real reappearance of the same genus (lazarus taxon or effect; jablonski, 1986; wignall & benton, 1999; fara, 2001), a case of morphological convergence (e.g., ?functional convergence: psammobiontic irregularina-type forms) of two different genera, or incompleteness of the fossil record perhaps in a period of generally low proliferation of thaumatoporellacens. in the latter case, thaumatoporellacenas might have survived the end-permian mass-extinction (e.g., knoll et al., 2007; bottjer et al., 2008; sahney & benton, 2008) and could then be considered as a longterm refugia species (e.g., harries et al., 1996). maybe the upper carboniferous to early triassic gap of any thau­ matoporella (or microfossils that could possibly be synonymised with the latter) record is just an apparent one. for example, a lobed form was described recently as bisphaera? improvisa from the middle permian of texas by nestell et al. (2006). not mentioned by the authors, b.? improvisa can morphologically barely be distinguished from the devonian irregularina lobata reitlinger, 1954 or other “bisphaera” species (vachard, 1994: fig. 15.1). the generic uncertainty was only “because of the long stratigraphic gap” (nestell et al., 2006: p. 170). if “cribrosphaera pertusa” described by bykova (1961) from the late ordovician of kazakhstan or bisphaera eomalevkensis described recently by sabirov & gushchin (2006) from the early ordovician of tajikistan, are also included, the stratigraphic range of thaumatoporellaceans (as interpreted here) would enlarge even more. the latter age however was doubted by vachard et al. (2010, p. 220) who instead assumed a devonian age. discussion: as already repeatedly stated, the high morphological variability of mesozoic thaumatoporella reprefigure 9: wall thickness (in µm) of thaumatoporella? malevkensis (birina) nov. comb. (1-6) and thaumatoporella parvovesiculifera (raineri) (7-12). 1: antropov (1959: uslonia permira, upper frasnian of russia) 2: toomey et al. (1970: vermiporella sp., frasnian of canada) 3: wray (1967: frasnian of australia) 4: may (1994: vermiporella myna, givetian to frasnian of germany) 5: flügel & hötzl (1971: vermiporella cf. myna, givetian of germany) 6: this work. 7: flügel (1983, upper triassic of greece) figure 10: preservational aspects of upper cretaceous (“senonian”) thaumatoporella pia (a-d) compared to upper devonian eovolvox (from kaźmierczak, 1976: pl. 22, fig. 1, partly) (e) and middle devonian cribrauroria (from vachard, 1994: pl. 4, fig. 7) (f ). without scale. the intention of the example selection is only to show similar diagenetic phenomena without implication of any taxonomic connection. schlagintweit et al.: palaeozoic record of thaumatoporella pia, 1927 (incertae sedis)? geologia croatica 173 fossils, i.e. representatives of parathuramminid foraminifera and algae incertae sedis, possibly also to some unusual large calcisphaerids for instance. one common feature of these “foraminifera” in question is their single-chambered (monothalamous) test without internal partitions, combined with an obvious lack of any aperture. the aperture is the “ultimate opening of the last chamber cavity into the ambient environment” (hottinger, 2006) from “which protoplasma (pseudopodia) protrudes” to “assist in locomotion, capturing of food, and removal of waste products” (flügel, 2004, p. 453). it is also strange that the lack of this functional feature has not hindered these forms being assigned to foraminiferans and the establishment of a taxonomic concept including families and subfamilies that, though modified in some details, has also been adopted by loeblich & tappan (1987). some of these families were grouped together within the order parathuramminida mikhalevich by vachard (1994). for the taxa in question, it can be stated that most of them were established in times where it was the general consensus to describe new taxa with little illustrations (e.g., two in uslonia permira) insufficient to demonstrate the natural morphological variability. this was certainly one of the reasons that many different “species” have been established on the basis of morphology and size that should differ from already known taxa. for example, vachard (1994: fig. 15/1) nicely demonstrated that there are all types of gradual transitions from more or less spherical “tests” with one single slight constriction (e.g., bisphaera malevkensis) to highly constricted forms (e.g., bisphaera div. sp. and genus irregularina). so these morphological variations were used in the past as a stay of knowledge not only to delimit different “species” but also to differentiate independent genera. besides real morphological intergradations, the effect of different planes of cutting creates highly variable aspects in random thin-sections. this aspect of consideration was stressed by racki & sobón-podgórska (1993). another criterion of high taxonomic value in benthic foraminifera is the wall structure (loeblich & tappan, 1987; vachard et al., 2010) and without any doubt the presence or absence of pores in the wall and its microstructure are prime criteria of suprageneric importance (e.g., kaminski, 2004). in the devonian material there are not only specimens with and without detectable pores, but also ovoid to egg-shaped forms that display both within the same specimen. according to systematic consensus, those parts without apparent pores are referred to bisphaera birina, the perforate parts to cribrosphaeroides reitlinger (fig. 5). this “two in one” aspect, however, clearly evidences that in finely perforated walls this feature can be masked and be lost through diagenesis. let us remember that reitlinger (1954, p. 65, translated) in the diagnosis of cribrosphaera (later renamed as cribrosphaeroides) remarks that “the test has an irregular shape, similar in type to the irregulariinas and bisphaeras”. the diagnosis of bisphaera birina was given by loeblich & tappan (1987, p. 195) as follows: “test subglobular to pyriform, may have constriction suggesting a tendency to divide; wall single layered, of finely granular figure 11: hypothetical model of “cribrosphaeroides-bisphaera” life-cycle with interpretation as trophozoite and cyst stages respectively. examples from the (upper eifelian) of the hillesheim syncline, eifel hills, germany; thin-section k 39-9 (above) and k 44b (below). figure 12: cryptoendolithic specimen of thaumatoporella inside the test of a large-sized miliolid (modified from de castro, 1971, pl. 9, fig. 1). the stretching of the thaumatoporellacean body through the foraminiferan septal perforations (arrows) would not have been possible if the membrane was originally heavily calcified. here the impression of a tube under pressure that can be squeezed through small passages is evident (see schlagintweit & velić, 2012, for details). scale bars 1 mm. sentatives is considered to be the clue and the base for the interpretation of the palaeozoic material. in the liassic material from albania (e.g., pl. 2, fig. 1) there are transitional types of variously shaped and sized specimens with thick and thin walls, with pores and without detectable pores etc. apart from a narrower range of wall thickness, the same observations can be applied to the studied palaeozoic microgeologia croatica 66/3geologia croatica 174 calcite, perforate; no aperture observed”. an enlarged diagnosis is presented by vachard (1994, p. 34–35, translat ed): “test free (?), unilocular, sometimes slightly subdivided appearance by constrictions of the wall. dark, segregat ed wall, comparatively thin, finely perforate, sometimes double-layered with an internal fibrous layer”. as vachard correctly remarked, the inner fibrous layer may be present or absent as is also the case in mesozoic thaumatoporella (pl. 2d versus pl. 2e, pl. 3g). as the denoted bipartition of the “test” is not always visible in thin-section specimens (whether primary or due to the effect of sectioning) the genus name bisphaera might be misleading. the fibrous inner layer is in our opinion not recognizable in the original figurations of birina (1948a). the figures look like a filling of coarse-grained blocky calcite with crystals attached to the microcrystalline wall. as our examples shown in fig. 5 and pl. 5c, we also have the impression that the holotypes of both bisphaera malevkensis and b. irregularis exhibit tiny pores. furthermore, toomey et al. (1970, p. 972) reported the observation that “a few specimens (remark: of bisphaera) in which the test wall microstructure could be observed closely, showed slight indications of what may possibly be a perforated wall”. as has been shown by de castro (1990) for thau­ matoporella parvovesiculifera, the wall structure is controlled by diagenesis, leading to different preservational modes (fig. 10). similar preservational types (or preservational history) as observed in thaumatoporella were described in detail from devonian volvocacean algae (kaźmierczak, 1976) and acritarchs (kaźmierczak & kremer, 2005), e.g., post-mortem bacterial decomposition of a mucilaginous envelope and resulting cement precipitation. whether or not this observation is of taxonomic importance is unknown. although not diagnostic per se, it should be mentioned that a honey-comb pore pattern in tangential section of “us­ lonia” was indicated by antropov (1959) and has also been observed several times for thaumatoporella (e.g., radoičić, 1960: p. 137; imaizumi, 1965: p. 53). from mesozoic strata, (sub)spherical to ovoid shaped thaumatoporellaceans with or without one (rarely more than one) slight depression (constriction?) are well known (see for example isolated specimens in de castro (1990, pl. 6 therein, “forma globosa”) (pl. 3). in the literature they were also named thaumatoporella sp. (e.g., di stefano & ruberti, 2000: pl. 29, fig. 3; fabbi & santantonio, 2012: fig. 7f) or “primitive thaumatoporella sp.” (ruber ti et al., 2013: fig. 5c). the outer diameter of these spheroids ranges from about 0.25 mm up to 0.9 mm (often values between 0.4 and 0.6 mm). the micritic membrane is typically thin (~15 to ~18 µm) and appears mostly imperforate. occasionally, fine pores are dimly recognizable. the micritic membrane may be surrounded externally by a thin rim of slightly yellowish calcite (thickness ~30 to ~65 µm). the interior of the bodies is filled with sparry calcite or sometimes with an inner fibrous layer (pl. 3g), which sometimes is also observed in palaeozoic “bisphaera” specimens (vachard, 1994, p. 35, “...parfois double d´une couche interne fibreuse”). the spheroidal forms may co-occur with other thaumatoporellacean morphotypes or dominate the assemblage in micropaleontologically impoverished microbialitic layers. from cretaceous strata, scott (1978) described such forms (spheroidal incertae sedis) as micritosphaera ovalis (see pl. 3j-k), interpreted to represent a junior synonym of thaumatoporella pia recently by schlagintweit & velić (2012). the specimen showing an “interior ring” (scott, 1978, fig. 1g, refigured here in fig. 2b) and external wall “invaginations” was interpreted in this context as representing structures assigned to motherand daughtercolonies sensu de castro (1990). another specimen shown by scott (1978, fig. 1f) is fixed to a foraminiferan. interestingly, scott (1978) compared micritosphaera with the devonian bisphaera. both the mesozoic spheroids and their palaeozoic equivalents (pl. 3) are here interpreted as representing resting cyst stages as known for example from taxonomically different groups of protozoans (e.g., sleigh, 1989; prescott et al., 2002; funatani et al., 2010) or algae (e.g., moczydlowska, 2010). the function of a resting cysts (or dormant stage) in the life cycle may be the protection against unfavourable environmental conditions (e.g., verni & rosati, 2011; smirnov, 2008). the reversible process of encystation is called excystment taking place by a return to favourable conditions. the metabolically active protozoan growth (or feeding) stage is called trophozoite (e.g., khunkitti et al., 1998) (fig. 11). it is dominant in favorable environmental conditions. encystment goes along with the shape of the body morphology. generally, a spherical shape is approached by the cysts. as for the acritarchs (e.g., kaźmierczak & kremer, 2005), we believe that the wall of thaumatoporella? malevkensis (birina) nov. comb. was originally organic and flexible and became calcified early post-mortem. this assumption would also allow the transformation from variously shaped morphotypes to imotile sphaeroidal cysts. for micritosphaera, scott (1978, p. 509–510) remarked that “the variably shaped and arranged invaginations and protuberances in many specimens indicate that originally the wall was pliable; perhaps it was a combination of micritic and organic layers”. it is also worth mentioning that only recently irregularina, due to an assumed psammobiontic way of life and thereby the inferred possibility for movement and changeable morphology (requiring a flexible body wall), was compared to amoeboid protists (schlagintweit et al., 2013). cryptoendolithic thaumatoporellaceans often display body compression (as in a flexible tube) under pressure in order to squeeze into or through small openings of host skeletons (fig. 12). these body contractions would not be possible if thaumatoporellaceans possessed a rigid heavily calcified wall during their life-time. this observation was interpreted as an indication of a protozoan rather than algal nature for the thaumatoporellaceans (schlagintweit & velić, 2012; schlagintweit et al., 2013). it should be mentioned that de castro also discussed the adaptation of the globose morphotypes to environmental conditions such as hydrodynamic energy. it should then result from a rolling movement. in our material the spheroidal schlagintweit et al.: palaeozoic record of thaumatoporella pia, 1927 (incertae sedis)? geologia croatica 175 morphotype is always associated with other different morphotypes. this observation can either reflect mixing or an indication that the globose shape is not the result of hydrodynamism. but there are also examples illustrated in the literature of spheroidal morphotypes in paleoenvironments of reduced water energy. for example, graziano (2013: fig. 16) illustrated abundant thaumtoporellaceans in clotted microbial crusts from the early aptian of southern italy. spalluto (2011: fig. 5d) illustrated similar microfacies from the albian/cenomanian of apulia, s-italy. there are also further examples where these spheroidal thaumatoporellaceans occur associated with microbial laminites: gargasian (ruberti et al., 2013: fig. 5e) and upper cretaceous of s-italy (borgomano, 2000) or upper cretaceous of croatia (gušić & jelaska, 1990: pl. 6, fig. 3). these peculiarities could have been linked to the preponderance of special mesotrophic to oligotrophic (nutrient-deficient) conditions as discussed, e.g., for the early jurassic (fugagnoli, 2004), an acme period of thaumatoporellaceans (see sartoni & crescenti, 1959, 1963). the cyst interpretation model would fit the observed dominance of spheroidal thaumatoporellaceans in microbial intervals that reflect some kind of environmental changes or disturbances. romano & barattolo (2005) discussed the bioevents that followed the triassic-jurassic boundary mass extinction among the typical low-diversity lowermost liassic thaumatopore­ lla assemblage in terms of palaeoenvironmental conditions. considering thaumatoporella to be an r-strategy organism, they conclude that it represents a disaster taxon. generally, r-strategy organisms possess the ability for rapid reproduction and are thus predominat in times of unstable environments (e.g., reznick et al., 2002, for discussion). a cross-re ference to the dominance of a low diversity thaumatoporellacean assemblage in the aftermath of the triassic–jurassic boundary event might be the preponderance of bisphaera (over cri­ brosphaeroides and others) in the lower tournaisian (basalmost carboniferous), e.g., “bisphaera beds” (birina, 1948b; mamet & belford, 1968; sando et al., 1969; kalvoda, 1986, 1990, 2002; makhlina et al., 1993; reitlinger et al., 1996; in contemporary literature named as upper gumerovian and malevkian, cf. kulagina, 2013). this assemblage follows the terminal famennian mass-extinction (hangenberg event; e.g., walliser, 1984; kaiser, 2005). the occurrence of microbialites with abundant thaumatoporellacens (mostly spheroidal forms) during oceanic anoxic events (oaes) seems to be another interesting topic for further study (e.g., graziano, 2013: oae 1a, korbar et al., 2012: oae 2). a cross-reference is hereby given to the “out-of-balance” facies rich in microbial (“bacinellid”) crusts and other structures assumed to be coeval to the early aptian oae 1a (e.g., immenhauser et al., 2005; rameil et al., 2010). also the increased abundance of devonian thaumatoporallecean-like forms corresponds to dysoxic episodes and events, e.g., in the upper givetian, basal frasnian or with the middle frasnian, e.g., in the pa. punctata zone (hladil et al., 2009). it is very likely that both the major and medium-magnitude palaeozoic events which caused proliferation of microbially dominated benthic communities and organomineralization of sediment in the post-crisis period (bourque et al., 2004) led to the right setting for production and release of the cysts. this is particularly true for the early tournaisian times when plenty of them are locally preserved in the sedimentary rocks (see “bisphaera beds” above). an interesting observation, emphasized by d. vachard in his review to our paper, relates to the calcification of cysts and formation of carbonate cements: the palaeozoic forms frequently show an inner, isopachous, radial-fibrous to bladed ‘light’ layer that is often continued by centripetal growth of drusic cement, but is not so frequent in the mesozoic. however, there are many exceptions. for example, makhlina et al. (1993, pl. 1) or kulagina (2013, fig. 6a, d and e) show bisphaera sections where an inner ‘light’ layer is absent or very irregular, and hance et al. (2011, p. 243, pl. 2/6) illustrated a bisphaera where the ‘light’ layer is absent on the inner side, but is greatly developed on the outer side of the ‘dark’ calcified wall – just inside out; here, in addition, the inner drusic cement is only at the very base of a geopetal fill. according to comparison of the very tiny and coarsely porous honeycombed membranes, e.g., between the palaeozoic bisphaera and cribrosphaeroides, or palaeozoic vs. mesozoic forms, we have found that the formation of an inner vs. outer cement layers reflect mainly the early diagenetic permeability of the calcified and coated membrane. the fine porous fabrics of bisphaera type were rapidly quasi-hermetically sealed and crystallization proceeded in the same way as in any closed microcavities (e.g. ostracods with firmly closed valves). however, the coarsely porous structures exchanged fluids with ambient pore waters for longer periods of time, and the outer cement layers gradually came to be predominant in volume (as for any porous bioclasts covered by cements). the latter may, but not necessarily, also contain a thin fibrous layer. consequently, the problem of a bilayered “bisphaera wall” and the regular presence of its fibrous inner part is possibly more complex than previously thought (vachard et al., 2010; richardson, 2012). in addition, the extracellular precipitation on an organic template (in vivo) can also be mistaken for early diagenetic, microbially-mediated fibrous crusts, as the latter are particularly common in the periods coming after the carbonate productivity crises and/or major regressions; the indicators of this, although not directly connected to the thaumatoporella facies, are cements in microbialites (riding, 2005) or “stromatactis” (e.g., hladil et al., 2007, 2008; aubrecht et al., 2009). eventually, secular variations in overall marine cementation intensities and morphologies might also have played a role. according to kiessling (2002), the amount of reef cements vary through time with medium to high amounts in the palaeozoic and lower/middle triassic as compared to the usually low mean cement content in jurassic to cenozoic times (see also flügel, 2004). although thaumatoporella is not restricted to reef facies and also thrives in interto subtidal inner platform environments (often still peri-reefal), different conditions for marine cement geologia croatica 66/3geologia croatica 176 precipitation in the palaeozoic should be also taken into account. it is well known that protozoan cysts may be round or irregular shaped, displaying singleor double-layered, thin or thick walls with a structure being different from the noncyst stage (e.g., smirnov, 2008). within the protozoa, a considerable variation in the cyst wall microstructure is present (laybourn-parry, 1984, for details). sometimes, different cyst wall layers are named ectocyst (outermost layer) and endocyst (inner layer/s) (e.g., kida & matsuoka, 2006). this ectocyst is typically a dense layer. from the upper cretaceous isolated specimens de castro (1990) noted an external coating, (different to the dense microgranular membrane), assigned to the peripherical parts of the wall. it could represent the yellowish radial-fibrous calcitic outer rim observable in the thin-section specimens. an interpretation as a calcified mucilaginous substance known to envelop resting cysts (“mucoid layer”) as reported from other organisms (e.g., verni & rosati, 2011: fig. 1f) seems possible. in some forms (pl. 3a), this outer rim exhibits a finely jagged outline that could be compared to the finger-like protrusions covering the entire cyst surface and produced during the final step in cyst formation of some protozoans (e.g., verni & rosati, 2011, fig. 1e). the formation of a dense ectocyst layer could be a hypothesis for the thin and usually imperforate character of “bisphaera”, contrasting the perforate non-cyst stage inferred for “cribro­ sphaeroides”. the formation of the dense cyst wall layer during the encystment process might be evidenced by the specimens showing the “two in one aspect”, parts with discernible fine pores and others without (fig. 5). concerning the size, the cysts of the giant amoebozoa chaos linnaeus attain a medium size of 0.25 mm (good kov et al., 1999) but may be up to 0.6 mm. for givetian “bisphaera” specimens from w-germany, flügel & hötzl (1971: p. 365) indicate diameters from 0.1 to 0.525 mm exhibiting wall thicknesses of 0.01 to 0.03 mm. the cyst wall of modern protozoans is distinctly thinner, often less than 1 µm, up to some microns only (e.g., kida & matsuoka, 2006; verni & rosati, 2011). the holotype of the type-species bisphaera malevkensis birina has a diameter of 0.53 mm and other representatives of the genus range up to 0.65 mm. from tournaisian strata, bisphaera specimens of up to 1.1 mm are known (j. kalvoda, pers. comm.). in early jurassic to upper cretaceous spheroidal thaumatoporella, the outer diameter ranges from about 0.25 mm up to 0.9 mm (often values between 0.4 and 0.6 mm). for “micritisphaera” (that we interpret as a synonym of thaumatoporella), scott (1978) indicates diameters from 0.49 mm to 1.18 mm. a further cross-reference of the studied devonian specimens to mesozoic thaumatoporella is given also by forms that were likely attached to hard substrates. such specimens of “bisphaera” were illustrated by conil in bouckaert et al. (1977: figs. 57-58) (figs. 7a-b). they are characterized by thin walls without detectable pores. the part of the wall attached to the substrate closely follows its morphology, and may result in a wavy outline whereas the non-attached part displays a smooth convex outline. for the purpose of completeness, it must be mentioned that vachard (1994: p. 30) is not convinced that the mentioned bisphaera specimens were in fact attached forms. he favoured an interpretation as test deformations resulting from a possible psammobiontic way of life not from substrate irregularities. we do not follow this view and want to draw attention to fig. 58 of conil in bouckaert et al. (1977), refigured here in fig. 7a where in our opinion a basal substrate (concave upper side pelecypod shell?) is dimly recognizable. anyway, homeomorphic attaching specimens are well known from mesozoic thaumatoporellaceans (e.g., de castro, 1997: pl. 24, fig. 1) (fig. 7c). in the original description of “uslonia per­ mira”, antropov (1959) also indicated that the test was most likely attaching. in this respect it must be mentioned, that reitlinger (1954: pl. 21, fig. 1) illustrated an elongated specimen of cribrosphaera? sp. showing constrictions with a thin micritic perforated wall that we interpret to have been fixed to a bioclast. last but not least, both the palaeozoic and mesozoic specimens exhibit internal structures or bodies that were interpreted as thaumatoporella daughter-colonies by de castro (1990). for some palaeozoic “usloniidae”, vachard (1994: p. 37) and vachard & clement (1994: p. 300) already stated the resemblances to mesozoic thaumatoporellaceans. they compare internal bodies observed in bisphaera and cribrosphaeroides with the thaumatoporellacean daughter-colonies sensu de castro (1990). interestingly, mes­ sopotamella angulata described by dragas tan et al. (1985) from the upper triassic of greece was compared morphologically by the authors with uslonia antropov. mes­ sopotamella is considered a thaumatoporella with thin walls without detectable pores where some specimens may exhibit tapering (“angular”) ends (see also de castro, 1990). considering the two illustrations (though of not good quality) of uslonia permira presented by antropov (1959), we infer that both exhibit barely recognizable thin-walled “internal bodies”. such structural details inside the “test” of uslonia however were not mentioned in the original description. in this point, we disagree with the assumption of vachard (1994) of an abiogenic nature for uslonia representing “sparitic, large and irregular debris” or cortoids. due to our assumptions and interpretations, the foraminiferan family usloniidae in the sense of loeblich & tappan (1987) needs a taxonomic reconsideration. with the assumed synonymization of uslonia antropov, 1959 with thaumatoporella pia, 1927, the family-group name usloniidae loses the reference to a type genus (article 35, international code of zoological nomenclature iczn). normally, however, the “validity of family-group names” is “not affected”….”when the name of a type genus of a nominal family-group taxon is considered to be a junior synonym of the name of another nominal genus” and “the family-group name is not to be replaced on that account alone” (article 40 iczn). besides “uslonia”, the family usloniidae contains two other genera bisphaera birina and parphia miklukho-maklay. bisphaera is also considered here as representing a thaumatoporellacean-like microfossil and for schlagintweit et al.: palaeozoic record of thaumatoporella pia, 1927 (incertae sedis)? geologia croatica 177 the rather large spherical “bodies” of parphia with its finely perforated micritic wall a possible algal origin is more likely than representing a unilocular foraminifer. the situation becomes even more complex as the family thaumatoporellaceae was created in 1988 by de castro, the usloniidae by miklukho-maklay in 1963 and finally the irregularininae (as a subfamily of the parathuramminidae) by zadorozhnyy & yuferev in 1984. so just from the date of publication, the usloniidae would have priority. 4. conclusions the long-term practice of establishing different taxa of palaeozoic parathuramminids/incertae sedis on the basis of differences in morphology and size (mainly in random thinsections) is as equally problematic as taking into account the different aspects of the wall structures. these might represent either true original differences or just expressions of various preservational (e.g., alteration, recrystallization, cement fringes) or developmental stages (phases of life cycles). in mesozoic thaumatoporella, it is the consensus to accept comparable to equivalent taphonomic aspects, as preservational modes of a single taxon and not different genera. the widely accepted concept of polymorphism of mesozoic-early cenozoic thaumatoporella is discussed for some seemingly homeomorphic palaeozoic taxa leading in our interpretation to a rather radical synonymization. with thaumatoporella having priority, bisphaera birina, cri­ brosphaeroides reitlinger, uslonia antropov and vermiporella myna wray (not the genus vermiporella stolley) are here interpreted as possible junior synonyms. the aforementioned genera and their species were already treated as highly controversial among micropalaeontologists concerning both their possible synonymies and biogenic nature. also from the mesozoic, a lot of genera and species are considered to represent synonyms of a single taxon, thau­ matoporella pia (or species of it): polygonella elliott, micritosphaera scott, messopotamella dragastan et al., lithoporella elliotti (emberger) and vermiporella crisiae dragastan et al. irregularina bykova also might represent thaumatoporellaceans, respectively psammobiontic forms. in analogy to mesozoic homeomorphs, bisphaera is proposed as representing a possible thaumatoporella resting cyst stage. the interpretation of bisphaera-type spheroids is compatible with the lack of any aperture, an observation that always made the attribution of these forms to monothalamous foraminifera problematic. mesozoic equivalents were described as micritosphaera scott or “primitive thaumatoporellaceans”, “thaumatoporella sp.” in the literature. the assumed cyst stages of both thaumatoporella? malevkensis (birina) nov. comb. and thaumatoporella parvovesiculif­ era (raineri) are almost identical with respect to morphology, size, wall thickness, both exhibiting also various aspects of preservation. the possible palaeozoic record of thaumatoporellaceans would suggest that they represent long-living and morphologically rather conservative microorganisms. the assumed ability to change morphology during their life-time and motility, the optional occurrence in completely shaded habitats and the inferred formation of resting cysts challenges the attribution of thaumatoporelaceans to algae. these aspects instead are compatible with a protozoan nature. acknowledgement the second author appreciates the financial support provided by gli ascr (rvo67985831-9335). the third author is thankful for support by the german research foundation (dfg le580/10). the following persons (in alphabetical order) are thanked for providing thin-sections and/or photographs, or giving the permission for re-illustrations of photographs from their works (in alphabetical order): alessio checconi (perugia), hans-jürgen gawlick (leoben), ivan gušić (zagreb), boguslav kolodziej (kraków), oliver krische (leoben), richard lein (wien), arturo raspini (florence), rajka radoičić (belgrade), roberto rettori (perugia), daniel vachard (lille) and ivo velić (zagreb). marina afanasieva (moscow), elena kulagina (ufa), jiri kalvoda (brno), winfried werner (munich) and daniel vachard (lille) helped with the acquisition of literature. discussions on topics referred to taxonomic codes with bruno granier (brest) are kindly acknowledged. the reviewers ioan bucur (cluj-napoca) and daniel vachard (lille) are thanked for helpful and stimulating comments (even if we could not follow several remarks provided by the last reviewer). last but not least, we thank julie robson for the english corrections. references afanasieva, m.s. & amon, e.o. (2011): devonian radiolarians of russia.– paleontological journal, 45/11, 1313–1532. doi: 10.1134/ s0031030111110013. antropov, i.a. (1950): new foraminiferal species of the upper devonian of some areas of the eastern russian platform (in russian).– izvestiya kazanskogo filiala, akademiya nauk sssr, geologicheskiy institut, 1, 21–33. antropov, i.a. (1959): foraminifera from the devonian of tatar (in russian).– izvestiya kazanskogo filiala, akademiya nauk sssr, ser. geol. nauk, 7, 11–34. aubrecht, r., schlögl, j., krobicki, m., wierzbowski, h., matyja, b.a. & wierzbowski, a. (2009): middle juras sic stro matactis mud-mounds in the pieniny klippen belt (carpathians) – a possible clue to the origin of stromatactis.– sed. geol., 213/3–4, 97–112. doi:10.1016/j.sedgeo.2008.11.007. bábek, o., přikryl, t. & hladil, j. (2007): progressive drowning of carbonate platform in the moravo-silesian basin (czech republic) before the frasnian/famennian event: facies, compositional variations and gamma-ray spectrometry.– facies, 53/2, 293–316. doi: 10.1007/s10347-006-0095-8. barattolo, f. & romano, r. (2005): some bioevents at the triassic-liassic boundary in the shallow water environment.– bolle tino della societá geologica italiana, 124, 123–142. belka, z., narkiewicz, m. (2008): devonian.– in: mccann, t. (ed.): the geology of central europe, vol. 1, precambrian and palaeozoic. geological society london, 383–410. geologia croatica 66/3geologia croatica 178 birina, l.m. (1948a): new species of calcareous algae and foraminifera of the boundary strata of the devonian and carboniferous (in russian).– sovetskaya geologiya, 28, 154–159. birina, l.m. (1948b): a scheme of detailed stratigraphy and depositionary conditions of the devonian-carboniferous boundary beds in the southern part of the moscow region (in russian).– sovetskaya geologiya, 1948/28, 146–153. bosák, p., mylroie, j.e., hladil, j., carew, j.l. & slavik, l. (2002): blow hole cave: an unroofed cave on san salvador island, the bahamas, and its importance for detection of paleokarst caves on fossil carbonate platforms.– acta carsologica, 31, 51–74. bottjer, d.j., clapham, m.e., fraiser, m.l. & powers, c.m. (2008): understanding mechanisms for the end-permian mass extinction and the protracted early triassic aftermath and recovery.– gsa today, 18, 4–10. borgomano, j.r.f. (2000): the upper cretaceous carbonates of the gargano-murge region, southern italy: a model of platform-tobasin transition.– aapg bulletin, 84 (10): 1561–1588. doi: 10.1306/8626bf01-173b-11d7-8645000102c1865d. bouckaert, j., conil, r., dusar, m. & streel, m. (1977): stratigraphic interpretation of the tohogne borehole (province of luxembourg). devonian – carboniferous transition.– annales de la société géologique de belgique, 100, 87–101. bourque, p.a., neuweiler, f. & boulvain, f. (2004): the mudmound system: products and processes.– 32nd intl. geol. congr., florence, italy. cd-rom abstracts 2, 1079. bucur, i.i., hoffmann, m. & kolodziej, b. (2005): upper jurassic-lowermost cretaceous benthic algae from tethys and the european platform: a case study from poland.– revista espanola micropaleontología, 37/1, 105–129. burchette, t.p. (1981): european devonian reefs: a review of current concepts and models.– society of economic paleontolologists and mineralogists, special publication, 30, 85–142. bykova, e.v. (1955): foraminifers and radiolarians from the devonian of the volga-ural region and central devonian field and their significance for stratigraphy.–transactions of the all-union oil, scientific-research and geological-survey institute vnigri, new series, 87, 5–190. bykova, e.v. (1961): caradocian foraminifera of eastern kazakhstan (in russian).– izvestiia akademii nauk kazakhskoj ssr (inst. geol. nauk), 1–119. caffau, m., pugliese, n. & pleničar, m. (1996): the development of the mollusc fauna in the cenomanian of the stratigraphic sequence of visogliano (karst of trieste, italy).– geologija, 37/38 (1994-1995), 87–121. checconi, a., rettori, r. & spalluto, l. (2008): biostratigrafia a foraminiferi del cretaceo superiore della successione di parco priore (calcare di altamura, piattaforma apula, italia meridionale).– annali dell´ università degli studi di ferrara museologia scientifica e naturalistica, 4, 1–9. chuvashov, b.i. (1965): foraminifers and algae from the upper devonian sediments on the western slope of the central and southern urals. in: foraminifers of the devonian and permian of the urals (in russian).– sbornik po voprosam stratigrafii no 8, trudy instituta geologii, akademiya nauk sssr (sverdlovsk), 74, 3–153. conil, r. & lys, m. (1964): materiaux pour l’etude micropaleontologique du dinantien de la belgique et de la france (resnois). parts 1–2. algues et foraminifères.– mémoires de l´instiute géologique de l´université de louvain, 23, 1–296. de castro, p. (1967): su alcune tallofite del mesozoico in campania. stratigrafia e paleontologia.– bolletino della societá dei naturalisti in napoli, 78, 87–167. de castro, p. (1971): osservazioni su raadshoovenia van den bold et i suoi rapporti col nuovo genere scandonea (foraminiferida, mioliolacea).– bolletino della societá dei naturalisti in napoli, 80, 161–236. de castro, p. (1988): observations on thaumatoporellaceans.– atti del 74° congresso della societá geologica italiana, a245–a249. de castro, p. (1990): thaumatoporelle: conoscenze attuali e approcio all’interpretazione.– bolletino della societá paleontologica italiana, 29/2, 179–206. de castro, p. (1991): on the cortical layer of thaumatoporellaleans (green algae dasycladales).– abstracts 5th int. symp. fossil algae capri, 7–12 april 1991, 16–17. de castro, p. (1997): introduzione allo studio in sezione sottile delle dasicladali fossili (in italian and english).– quaderni della accademia pontaniana, 22, 1–126. di stefano, p. & ruberti, d. (2000): cenomanian rudist-dominated shelf-margin limestones from the panormide carbonate platform (sicily, italy): facies analysis and sequence stratigraphy.– facies, 42/1, 133–160. doi: 10.1007/bf02562570. dragastan, o., papanikos, d. & papanikos, p. (1985): foraminifères, algues et microproblematica du trias de messopotamos, épire (grèce continentale).– revue de micropaléontologie, 27/4, 244–248. düzbastilar, m.k. (1991): notes on the jurassic-tertiary calcareous algae of the izmir region (west anatolia) (solenoporaceae) (in turkish).– geological bulletin of turkey, 34, 59–72. edgell, h.s. (2004): upper devonian and lower carboniferous foraminifera from the canning basin, western australia.– micropaleontology, 50/1, 1–26. doi: 10.2113/50.1.1 elliott, g.f. (1957): new calcareous algae from the arabian peninsula.– micropaleontology, 3, 227–230. emberger, j. (1957): lithoporella elliotti nov. sp., mélobésiée nouvelle du jurassique supérieur des monts des oulad-nail, atlas saharien (algérie).– bulletin de la societé géologique de france, ser. 6/7, 625–629. emmerich, a., zamparelli, v., bechstädt, t. & zühlke, r. (2005) : the reefal margin and slope of a middle triassic carbonate platform: the latemar (dolomites, italy).– facies, 50/3–4, 573–614. doi: 10.1007/s10347-004-0033-6. fabbi, s. & santantonio, m. (2012): footwall progradation in synrift carbonate platform-slope systems (early jurassic, northern apennines, italy).– sedimentary geology, 281, 21–34. doi: 10.1016/j. sedgeo.2012.07.008. faber, p., vogel, k. & winter, j. (1977): beziehungen zwischen morphologischen merkmalen der brachiopoden und fazies, dargestellt an beispielen des mitteldevons der eifel und südmarokkos.– neues jahrbuch für geologie und paläontologie abhandlungen, 154, 21–60. fara, e. (2001): what are lazarus taxa?– geological journal, 36/3–4: 291–303. doi: 10.1002/gj.879. feng, q., gong, y.m. & riding, r. (2010): mid-late devonian calcified marine algae and cyanobacteria, south china.– journal of pa-journal of paleontolology, 84/4, 569–587. doi: 10.1666/09-108.1. fenninger, a. & hötzl, h. (1967): die mikrofauna und –flora des plassenund tressensteinkalkes der typlokalität (nördliche kalkalpen).– neues jahrbuch für geologie und paläontologie abhandlun-neues jahrbuch für geologie und paläontologie abhandlungen, 128, 1–37. fischer, u. (1999): paläoökologie einer korallenvergesellschaftung aus dem unteren givet der hillesheimer mulde bei kerpen, eifel.– institute of geology and palaeontology, university of stuttgart (unpublished diploma thesis), 98 p. flügel, e. (1983): mikrofazies der pantokrator-kalke (lias) von korfu, griechenland.– facies, 8/1, 263–300. doi: 10.1007/bf02536744. flügel, e. (2004): microfacies of carbonate rocks – analysis, interpretation and application. 2nd edition. springer verlag, berlin, hei-2nd edition. springer verlag, berlin, heidelberg, new york, pp. 1–984. doi:10.1007/978-3-642-03796-2_1. flügel, e. & hötzl, h. (1971): foraminiferen, calcisphaeren und kalkalgen aus dem schwelmer kalk (givet) von letmathe im sauerland.– neues jahrbuch geologie paläontologie abhandlungen, 137, 358–395. schlagintweit et al.: palaeozoic record of thaumatoporella pia, 1927 (incertae sedis)? geologia croatica 179 franke, w. (2000): the mid-european segment of the variscides: tectonostratigraphic units, terrane boundaries and plate tectonic evolution.– in: franke, w., haak, v., oncken, o. & tanner, d. (eds.), orogenic processes: quantification and modelling in the variscan belt. geological society london special publications, 179, 35–61. fugagnoli, a. (2004): trophic regimes of benthic foraminiferal assemblages in lower jurassic shallow water carbonates from northeastern italy (calcari grigi, trento platform, venetian prealps).– palaeogeogr., palaeoclimatol., palaeoecol., 205, 111–130. doi: 10.1016/j.palaeo.2003.12.004. funatani, r., kida, a., watoh, t. & matsuoka, t. (2010): morphological events during rest cyst formation in the ciliate colpoda cucullus.– protistology, 6/3, 204–217. geršl, m. & hladil, j. (2004): gamma-ray and magnetic susceptibility correlation across a frasnian carbonate platform and the search for “punctata” equivalents in stromatoporoid-coral limestone facies of moravia.– geological quarterly, 48/3, 283–292. goodkov, a.v., smirnov, a.v. & skovorodkin, i.n. (1999): study of a rediscovered large freshwater multinucleate amoeba cha­ os illinoisense (kudo, 1950).– protistology, 1/2, 55–61. graziano, r. (2013): sedimentology, biostratigraphy and event stratigraphy of the early aptian oceanic anoxic event (oae1a) in the apulia carbonate platform margin – ionian basin system (gargano promontory, southern italy).– cretaceous research, 39, 78–111. doi: 10.1016/j.cretres.2012.05.014. gušić, i. & jelaska, v. (1990): upper cretaceous stratigraphy of the island of brač.– djela jugosl. akad. znanosti umjetnosti zagreb, 69, 1–160. haeckel, e. (1887): report on the radiolaria collected by h.m.s. “challenger” during the years 1873–1876.– report on scientific results of the voyage h.m.s. challenger. zoology, edinburgh, 18, 1–1803. hance, l., hou, h., vachard, d., devuyst, f.x., kalvoda, j., poty, e. & wu, x. (2011): upper famennian to visean foraminifers and some carbonate microproblematica from south china – hunan, guangxi and guizhou.– beijing, beijing geol. publ. house, 359 p. harries, p.j., kauffman, e.g. & hansen, t.a. (1996): models for biotic survival following mass extinction.– in: hart, m.b. (ed.): biotic revovery from mass extinction events. geological society spe cial publication, 102, 41–60. hladil, j. (1994): moravian middle and late devonian buildups: evolution in time and space with respect to laurussian shelf.– courier forschungsinstitut senckenberg, 172, 111–125. hladil, j. (2002): geophysical records of dispersed weathering products on the frasnian carbonate platform and early famennian ramps in moravia, czech republic: proxies for eustasy and palaeoclimate.– palaeogeogr., palaeoclimatol., palaeoecol., 181/1–3, 213–250. doi: 10.1016/s0031-0182(01)00480-1. hladil, j. (2007): eifelian – frasnian amphipora limestones, biostromes and bioherms, moravian karst, czech republic.– in: vennin, e., aretz, m., boulvain, f. & munnecke, a. (eds.): facies from palaeozoic reefs and bioaccumulations.– memoires du museum national d´histoire naturelle, 195, 187–189. hladil, j., koptíková, l, galle, a., sedláček, v., pruner, p., schnabl, p., langrová, a., bábek, o., frána, j., hla díková, j., otava, j. & geršl, m. (2009): early middle frasnian platform reef strata in the moravian karst interpreted as recording the atmospheric dust changes: the key to understanding perturbations in the punctata conodont zone.– bull. geosci., 84/1, 75–106. doi: 10.3140/bull.geosci.1113. hladil, j., koptikova, l., lisa, l., cejchan, p., ruzicka, m., kulaviak, l., adamovic, j., janecka, j., vecer, m., dra hos, j. & havlica, j. (2008): stromatactis and stromatactum pattern formation in sediment: constraints from fluid mechanics and rheology and implications for environments, sedimentary architecture and cyclostratigraphy.– in: kim, a.i., salimova, f.a. & meshchankina, n.a. (eds.): global alignments of lower devonian carbonate and clastic sequences, contributions, tashkent, sealmag press, 36–40. hladil, j., koptikova, l., ruzicka, m. & kulaviak, l. (2007): experimental effects of surfactants on the production of stromatactis-shaped cavities in artificial carbonate sediments.– bull. geosci., 82/1, 37–50. doi: 10.3140/bull.geosci.2007.01.37. hottinger, l. (2006): illustrated glossary of terms used in foraminiferal research.– carnets de géologie – notebooks on geology, mem. 2006/02 (cg2006_m02). doi: 10.4267/2042/5832. imaizumi, r. (1965): late jurassic algae from honsu and shikoku, japan.– the science reports of the tohoku university, ser. 2 (geol), 37, 49–62. immenhauser, a., hillgärtner, h. & van bentum, e. (2005): microbial-foraminiferal episodes in the early aptian of the southern tethyan margin: ecological significance and possible relation to oceanic anoxic event 1a.– sedimentology, 52/1, 77–99. doi: 10.1111/j.1365-3091.2004.00683.x jablonski, d. (1986): causes and consequences of mass extinctions: a comparative approach.– in: elliott, d.k. (ed.): dynamics of extinctions, 183–229. wiley & sons, new york. jeź, j., otoničar, b., fuček, l., ogorolec, b. (2011): late cretaceous sedimentary evolution of a northern sector of the adriatic carbonate platform (matarsko podolje, sw slovenia).– facies, 57/3, 447–468. doi: 10.1007/s10347-010-0249-6. johnson, j.h. (1965): coralline algae from the cretaceous and early tertiary of greece.– journal of paleontology, 39, 802–814. johnson, j.h. (1970): ordovician algae from boulders of in silurian deposits of new world island, new foundland.– journal of paleontology, 44, 1055–1059. johnson, j.h. & kaska, h.v. (1965): fossil algae from guatemala.– professional contributions colorado school of mines, 1, 1–152. juyal, k.p., suttner, t.j. & hubmann, b. (2009): silurian to devonian microfossils from the saser brangsa and aq tash formations, eastern karakoram, india.– ber. inst. erdwiss. k.-f.-univ. graz, 14, 40. kaiser, s.i. (2005): mass extinctions, climatic and oceanographic changes at the devonian/carboniferous boundary.– phd thesis ruhr university bochum, 156 pp. http://www-brs.ub.ruhr-uni-bochum. de/netahtml/hss/diss/kaisersandraisabella/diss.pdf kaldun, a. (1998): faziesanalyse mitteldevonischer schichten im grenzbereich eifelium/givetium am bahneinschnitt nohn, eifel.– institute of geology and palaeontology, university of stuttgart (unpublished diploma thesis), 67 p. kalvoda, j. (1986): upper frasnian-lower tournaisian events and evolution of calcareous foraminifera, close links to climatic changes.– in: walliser, o.e. (ed.) global bio-events: a critical approach. lecture notes in earth sciences, 8, 225–236. doi: 10.1007/ bfb0010209. kalvoda, j. (1990): foraminiferal zonation of the upper devonian and lower carboniferous in moravia (czechoslovakia).– acta musei moraviae scientiae naturales, 75, 71–93. kalvoda, j. (2002): late devonian-early carboniferous foraminiferal fauna: zonations, evolutionary events, paleobiogeography and tectonic implications.– folia, geologia, brno, 39, 1–213. kalvoda, j., bábek, o., fatka, o., leichmann, j., melichar, r., nehyba, s. & špaček, p. (2008): brunovistulian terrane (bohemian massif, central europe) from late proterozoic to late paleozoic: a review.– international journal of earth sciences, 97/3, 497–518. doi: 10.1007/s00531-007-0183-1. kaminski, m.a. (2004): the year 200 classification of the agglutinated foraminifera.– in: bubík, m. & kaminski, m.a. (eds.): proceedings of the sixth international workshop on agglutinated foraminifera, grzybowski foundation special publication, 8, 237–255. geologia croatica 66/3geologia croatica 180 kaźmierczak, j. (1976): volvocacean nature of some palaeozoic non -radiosphaerid calcispheres and “parathuramminid” foraminifera.– acta palaeontologica polonica, 21/3, 245–258. kaźmierczak, j. & kremer, b. (2005): early post­mortem calcified devonian acritarchs as a source of calcispheric structures.– facies, 55, 554–565. doi: 10.1007/s10347-005-0071-8. kaźmierczak, j. & kremer, b. (2009): spore-like bodies in some early paleozoic acritarchs: clues to chlorococcalean affinities.– acta palaeontologica polonica, 54/3, 541–551. khunkitti, w., lloyd, d., furr, j.r. & russell, a.d. (1998): acanthamoeba castellani: growth, encystment, excystment and biocide susceptibility.– journal of infection, 36/1, 43–48. doi: org/ 10.1016/s0163-4453(98)93054-7. kida, a. & matsuoka, t. (2006): cyst wall formation in the ciliated protozoan colpoda cucullus: cyst wall is not originated from pellicle membranes.– invertebrate survival journal, 3, 77–83. kiessling, w. (2002): secular variations in the phanerozoic reef systems.– in: kiessling, w., flügel, e. & golonka, j. (eds.): phanerozoic reef patterns. sepm, spec. publ., 72, 625–690. knoll, a.h., bambach, r.k., payne, j.l., pruss, s. & fischer, w.w. (2007): paleophysiology and end-permian mass-extinction.– earth and planetary science letters, 256/3–4, 295–313. doi: 10.1016/j.epsl.2007.02.018. konoplina, o.r. (1959): foraminifers of the upper devonian sediments from the western part of ukraine (in ukrainian).– akademiya nauk ukrain. rsr, trudy institut geol. nauk, ser. stratigr. paleont., 26, 1–56. korbar, k., glumac, b., tesovič, b.c., cadieux, s.b. (2012): response of a carbonate platform to the cenomanian–turonian drowning and oae 2: a case study from the adriatic platform (dalmatia, croatia).– journal of sedimentary research, 82, 163–176. doi: 10.2110/jsr.2012/17. kozłowski, r. & kaźmiercak, j. (1968): on two ordovician calcareous algae.– acta palaeont. polonica, 8, 325–346. krebs, w. (1974): devonian carbonate complexes of central europe.– in: laporte, l.f. (ed.): reefs in time and space. society of economic paleontologists and mineralogists, special publication, 18, 155–208. kreutzer, l.h. (1992): photo-atlas of the variscan carbonate sequences in the carnic alps (austria/italy).– abh. geol. b.-a., 47, 1–129. kulagina, e.i. (2013): taxonomic diversity of foraminifers of the devoniancarboniferous boundary interval in the south urals.– bull. geosci., 88/2, 265–282. doi: 10.3140/bull.geosci.1347. laybourn-parry, j. (1984): a functional biology of free-living protozoa.– university of california press, berkley & los angeles, 230 p. leinfelder, r.r., nose, m., schmid, d.u. & werner, w. (1993): the importance of microbial crusts in upper jurassic reef formation.– facies, 29, 195–230. doi: 10.1007/bf02536929. loeblich, a.r. jr. & tappan, h. (1987): foraminiferal genera and their classification.– 2 volumes (van nostrand reinhold) new york, 970 p. makhlina, m.k., vdovenko, m.v., alekseev, a.s., byvsheva, t.v., donakova, l.m., zhulitova, v.e., konovova, l.i., umnova, n.i. & shik, e.m. (1993): the lower carboniferous of the moscow syneclise and voronezh anteclise.– moscow, nauka, 221 p. mamet, b. & belford, d.j. (1968): carboniferous foraminifera, bonaparte gulf basin, northwestern australia.– micropaleontology, 14/3, 339–347. mamet, b. & préat, a. (2009): algues et microfossiles problématiques du dévonien moyen du “fondry des chiens” (bord sud du synclinorium de dinant, belgique): implications paléobathymétriques.– revue de micropaléontologie, 52/3, 249–263. doi: 10.1016/j.revmic.2008.06.001. mamet, b., préat, a. & lehmami, m. (1999): algues calcaires marines du dévonien marocain (meseta).– revue de micropaléontologie, 42/4, 301–314. doi: 10.1016/s0035-1598(99)90049-1. may, a. (1994): foraminiferen, kalkalgen und andere mikrofossilien aus dem givetium und frasnium (devon) des sauerlandes (rheinisches schiefergebirge).– dortmunder beiträge zur landeskunde, naturwissenschaftliche mitteilungen, 28, 7–31. miklukho-maklay, a.d. (1963): upper paleozoic of central asia. leningrad, leningradskiy universitet. moczydlowska, m. (2010): life cycle of early cambrian microalgae from the skiagia­plexus acritarchs.– paleontological journal, 84/2, 216–230. doi: 10.1666/09-117r.1. nestell, m.k., nestell, g.p., wardlaw, b.r. & sweatt, m.j. (2006): integrated biostratigraphy of foraminifers, radiolarians and conodonts in shallow and deep water middle permian (capitanian) deposits of the “rader slide”, guadalupe mountains, west texas.– stratigraphy, 3/3, 161–194. nicora, a., premoli silva, i. & arnaud-vanneau, a. (1995): paleogene larger foraminifer biostratigraphy from limalok guyot, site 871.– in: haggerty, j.a., premoli silva, i., rack, f. & mcnutt, m.k. (eds.): proc. odp scientific results, 144, 127–139. oncken, o., plesch, a., weber, j., ricken, w., schrader, s. (2000): passive margin detachment during arc-continental collision (central european variscides).– in: francke w., haak, v., oncken, o. & tanner, d. (eds.): orogenic processes; quantification and modelling in the variscan belt. geological society special publications, 179, 199–216. oncken, o. & weber, k. (1995): structure of the rhenohercynian fold belt.– in: dallmeyer, r.d., franke, w. & weber, k. (eds.): pre-permian geology of central and eastern europe. berlin, heidelberg, springer, 50–58. pia, j. (1927): thallophyta.– in: hirmer, m. (ed.): handbuch der palä-in: hirmer, m. (ed.): handbuch der paläonbotanik. oldenbourg, 31–136. pia, j. (1938): über thaumatoporella parvovesiculifera rain. spec. und ihr auftreten auf der insel naxos.– praktika tès akadèmias athènon, 13, 491–495. poyarkov, b.v. (1969): stratigraphy and foraminifera of the devonian deposits of tyan-shan (in russian).– akad. nauk kirgizskoy ssr inst. geol. frunze, 185 p. prescott, l.m., harley, j., klein, d. (2002): microbiology (5th edition).– mcgraw hill science, 1147 p. racki, g. & soboń-podgòrska, j. (1993): givetian and frasnian calcareous microbiotas of holy cross mountains.– acta palaeontologica polonica, 37/2–4, 255–289. radoičić, r. (1960): on little known species thaumatoporella par­ vovesiculifera (rain.) (in serbian).– vesnik, ser. 18, 133–140. raineri, r. (1922): alghe sifonee fossili della libia. nota i.– atti della società italiana di scienze naturali e del museo civico di storia naturale di milano, 61, 72–86. rameil, n., immenhauser, a., warrlich, g., hillgärtner, h. & droste, h.j. (2010): morphological patterns of aptian lithocodium­bacinella geobodies – relation to environment and scale.– sedimentology, 57/3, 883–911. doi: 10.1111/j.1365-3091. 2009.01124.x. raspini, a. (2011): shallow water carbonate platforms (late aptian, southern apennines) in the context of supraregional to global changes.– solid earth discussions, 3, 901–942. doi: 10.5194/sed-3-9012011. rauzer-chernousova, d.m. & fursenko, a.v., eds. (1959): principles of paleontology, part 1, protozoa. moscow, akademiya nauk sssr, 1–482. reitlinger, e.a. (1954): devonian foraminifera of some sections in the eastern part of the russian platform (in russian).– trudy vsesoyuznogo nauchno-issledovatel’skogo geologo-razvedochnogo neftyanogo instituta, paleontologicheskiy sbornik, 1, 52–81. schlagintweit et al.: palaeozoic record of thaumatoporella pia, 1927 (incertae sedis)? geologia croatica 181 reitlinger, e.a., vdovenko, m.v., gubareva, v.s. & shcherbakov, o.a. (1996): lower carboniferous.– in: wagner, r.h. et al. (eds.): the carboniferous of the world. iii the former ussr, mongolia, middle eastern platform, afghanistan & iran. instituto tecnológico geominero de españa, 23–54. reznick, d., bryant, m.j. & bashey, f. (2002): rand k-selection revisited: the role of population regulation in life-history evolution.– ecology, 83/6, 1509–1520. richardson, s.l. (2012): a phylogenetic perspective on the evolution of biomineralization in foraminifera.– gsa abstracts with programs, 44/7, 527. https://gsa.confex.com/gsa/2012am/webprogram/ paper211110.html. riding, r. (2005): phanerozoic reefal microbial carbonate abundance: comparisons with metazoan diversity, mass extinction events, and sea water saturation state.– revista española de micropaleontología, 37/1, 23–39. ruberti, d., bravi, s., carannante, g., vigorito, m. & simone, l. (2013): decline and recovery of the aptian carbonate factory in the southern apennine carbonate shelves (southern italy): climatic/oceanaographic vs. local tectonic controls.– cretaceous research, 39, 112–132. doi: 10.1016/j.cretres.2012.05.012. sabirov, a.a. & gushchin, s.b. (2006): new early ordovician calcareous foraminifers of the middle tien shan.– paleontological journal, 40/1, 11–19. doi: 10.1134/s0031030106010023. sahney, s. & benton, m.j. (2008): recovery from the most profound mass extinction of all time.– proceedings of the royal so ciety series b, 275, 759–765. salerno, c. (1997): karbonatfazielle und sedimentologische untersuchungen im tiefen givetium (mitteldevon) der sötenicher mulde (eifel) beim ort rinnen.– 98 p, institute of geology and palaeontol-98 p, institute of geology and palaeontology, university of stuttgart (unpublished diploma thesis). salerno, c. (2008): stromatoporen-fauna, fazies und paläoökologie von plattformkarbonaten aus dem unter-givetium der eifel (devon, rheinisches schiefergebirge).– zitteliana, b27, 1–129. sando, w.j., mamet, b.l. & dutro, j.t., jr. (1969): carboniferous megafaunal and microfaunal zonation in the northern cordillera of the united states.– usgs professional paper, 613 e, 1–29. sartoni, s. & crescenti, u. (1959): la zona a palaeodasycladus mediterraneus (pia) nel lias dell´appennino-meridionale.– giornale di geologia, 27, 161–302. sartoni, s. & crescenti, u. (1963): ricerche biostratigrafiche nel mesozoico dell´appennino meridionale.– giornale di geologia, 29, 153–302. schlagintweit, f. (1992): further record of calcareous algae (dasycladaceae, udoteaceae, solenoporaceae) from the upper cretaceous of the northern calcareous alps.– rev paléobiol, 11, 1–12. schlagintweit, f. (2013): thaumatoporella ladders unraveled.– stu dia universitates babeş-bolyai geologia, 58/1, 5–9. doi.org/ 10.5038/1937-8602.58.1.1. schlagintweit, f., gawlick, h.j., missoni, s., lein, r., vukaj, r. & hoxha, l. (2006): the triassic to early jurassic shallow-water carbonates of the rrapsha-tamara section (nw albania) as a part of the adriatic-dinaride carbonate platform.– in: tessadri-wackerle, m. (ed.): pangeo austria 2006. innsbruck university press, 310–311. schlagintweit, f., hladil, j. & nose, m. (2013): new observations and interpretations of the enigmatic poorly known late paleozoic irregularina bykova, 1955.– acta paleontologica romaniae, 9/1, 3–22. schlagintweit, f. & velić, i. (2011): new and poorly known middle jurassic larger benthic foraminifera from the karst dinarides of croatia.– geol. croat., 64/2, 81–99. doi: 104154/gc.2011.08 schlagintweit, f. & velić, i. (2012): foraminiferan tests and dasycladalean thalli as cryptic microhabitats for thaumatoporellacean algae from mesozoic (early jurassiclate cretaceous) platform carbonates.– facies, 58/1, 79–94. doi: 10.1007/s10347010-0263-8. schmid, d.u. (1996): marine mikrobolithe und mikroinkrustierer aus dem oberjura.– profil, 9, 101–251. schröder, s. & salerno, c. (2001): korallenfauna und fazies givetischer kalksteinabfolgen (cürten-/dreimühlen-formation) der dollendorfer mulde (devon, rheinisches schiefergebirge/eifel).– senckenbergiana lethaea, 81, 111– 134. scott, r.w. (1978): micritosphaera, a new cretaceous microfossil.– journal of paleontology, 52/2, 508–511. senowbari-daryan, b. (1984): mikroproblematika aus den obertriadischen riffkalken von sizilien.– münstersche forschungen zur geologie und paläontologie, 61, 1–81. senowbari-daryan, b., bucur, i.i. & abate, b. (1994): upper jurassic calcareous algae from the madonie mountains, sicily.– beiträge zur paläontologie, 19, 227–259. sleigh, m.a. (1989): protozoa and other protists.– arnold hodder, london, 352 p. smirnov, a. (2008): amoebas, lobose.– in: schaechter, m. (ed.): encyclopedia of microbiology. oxford, elsevier, 558–577. spalluto, l. (2011): facies evolution and sequence chronostratigraphy of a “mid”-cretaceous shallow-water carbonate succession of the apulia carbonate platform from the northern murge area (apulia, southern italy).– facies, 58/1, 17-36. doi: 10.1007/s10347011-0266-0. stolley, e. (1893): ueber silurische siphoneen.– neues jahrbuch für mineralogie, geologie und paläontologie, 2, 135–146. struve, w. (1963): das korallenmeer der eifel vor 300 mio. jahren funde, deutungen, probleme.– natur und museum, 93, 237–276. tišlar, j., vlahović, i., velić, i. & sokač, b. (2002): carbonate platform megafacies of the jurassic and cretaceous deposits of the karst dinarides.– geol. croat., 55/2, 139–170. toomey, d.f. & mamet, b.l. (1979): devonian protozoa.– in: house, m.r., scrutton, c.t. & bassett, m.g. (eds.): the devonian system. spec. paps. palaeontology, 23, 189–192. toomey, d.f., mountjoy, e.w. & mckenzie, w.s. (1970): upper devonian (frasnian) algae and foraminifera from the ancient wall carbonate complex, jasper national park, alberta canada.– canadian journal of earth sciences, 7, 946–981. utescher, t. (1992): mikrofazielle untersuchungen im unter-/mitteldevon-grenzbereich des westlichen rheinischen schiefergebirges.– decheniana, 145, 204–301. vachard, d. (1991): parathuramminides et moravamminides (microproblematica) de l´ emsien supérieur de la foramation moniello (cordilleres cantabriques, espagne).– revue de paléobiologie, 10/2, 255–299. vachard, d. (1994): foraminifères et moravamminides du givetien et du frasnien du domaine ligerien (massif amoricain, france.– palaeontographica, a 231, 1–92. vachard, d. & clement, b. (1994): l´hastarien (ex-tournaisien inférieur et moyen) á algues et foraminifères de la zone pélagonienne (attique, greece).– revue de micropaléontologie, 37/4, 289–319. vachard, d., pille, l. & gaillot, j. (2010): palaeozoic fora minifera: systématique, paléoécologie et réponses aux changements globaux.– revue de micropaléontologie, 53/4, 209–254. doi: 10.1016/j.revmic.2010.10.001. vecchio, e. & barattolo, f. (2006): periloculina (?) decastroi n. sp., a new foraminifer from the eocene (uppermost ypresian – lowermost lutetian) trentinara formation (southern apennines, italy).– bolletino della societá paleontologica italiana, 45/1, 147–158. vecchio, e. & hottinger, l. (2007): agglutinated conical foraminifera from the lower-middle eocene of the trentinara formation (southern italy).– facies, 53/4, 509–533. doi: 10.1007/s10347007-0112-6. verni, f. & rosati, g. (2011): resting cysts: a survival strategy in protozoa ciliophora.– italian journal of zoology, 78/2, 134–145. doi: 10.1080/11250003.2011.560579. geologia croatica 66/3geologia croatica 182 vishnevskaya, v.s. & sedaeva, k.m. (2002): a revision of some foraminiferal taxa of the order parathuramminida and problems of foraminiferal and radiolarian evolution (in russian).– paleontologicheskiy zhurnal, 6 (2002), 15–24. vissarionova, a.y. (1950): foraminiferal fauna from devonian strata of bashkiri (in russian).– bashkirskaya neft. ufa, 1950/1, 33–36. walliser, o.h. (1984): pleading for a natural d/c boundary.– courier forschungsberichte senckenberg, 67, 241–246. wignall, p.b. & benton, m.j. (1999): lazarus taxa and fossil abundance at times of biotic crisis.– journal of the geological society london, 156, 453–456. doi: 10.1144/gsjgs.156.3.0453. willey, j., sherwood, l. & woolverton, c. (2002): microbiology. part vii the diversity of the microbial world. chapter 27: protozoa. new york, mcgraw hill higher education, 583–594. willmer, b. (1998): fazies und paläoökologie von stromatoporenkorallen-kalken aus dem höheren givetium (rodert-fm., cisterzienser-mb.) der hillesheimer mulde bei niederehe, eifel.– institute of geology and palaeontology, university of stuttgart (unpublished diploma thesis) 163 p. wray, j.l. (1967): upper devonian calacareous algae from the canning basin, western australia.– professional contributions colorado school of mines, 3, 1–76. zadorozhnyy, v.m. & yuferev, o.v. (1984): phylum protozoa, class sarcodina, subclass foraminifera (in russian).– trudy insti-trudy instituta geologii i geofiziki, akademiya nauk sssr, sibirskoe otdelenie, 568, 70–113. zukalová, v. (2004): devonian stromatoporoid fauna from deep boreholes in northeastern moravia (in czech).– přírodovědné studie muzea prostějovska, 7, 1–74. manuscript received april 15, 2013 revised manuscript accepted july 09, 2013 available online october 16, 2013 2018 | 71/3 | 185 – 197 | 7 figs. | 2 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction ophiolitic fragments of oceanic lithosphere represent an important source of information needed for a better understanding of the origin of ancient ocean crust thus shedding more light on the evolution of orogenic belts and ophiolitic complexes documented worldwide (coleman, 1977; parlak et al., 1996, 2002; huot & maury, 2002; dilek, 2003; bortolotti, et al., 2005, 2013; dilek & furnes, 2011, 2014; saccani, et al., 2017). in addition to mafic rocks, ultramafic cumulate rocks that form the deepest part of the oceanic crust (i.e. ophiolitic crustal sequence), play a pivotal role in revealing ophiolite petrogenesis and geodynamic evolution (e.g. moores & jackson, 1974; coleman, 1977, 1981; parlak et al., 1996; ilbely, 2008; bagci, 2013). those cumulates are formed in magma chambers at higher depths as a consequence of the infilling of mantle-derived magmas. their geotectonic origin is usually linked to midoceanic ridges (mor) and supra-subduction zones (ssz) (sun & nesbitt, 1978; saunders et al., 1980; serri, 1981; the first record of ultramafic cumulates from the mt. kalnik ophiolite mélange in the sw part of the zagorje-mid-transdanubian zone (nw croatia): mineralogy, petrology, geochemistry and tectono-magmatic affinity damir slovenec1 and branimir šegvić2 1 croatian geological survey, sachsova 2, 10000 zagreb, croatia (corresponding author; e-mail: damir.slovenec@hgi-cgs.hr) 2 texas tech university, department of geosciences, 1200 memorial circle, lubbock 79409 tx, usa (e-mail: branimir.segvic@ttu.edu) doi: 10.4154/gc.2018.17 abstract ultramafic cumulate rocks represent the rarest allochthonous fragments of the mesozoic oceanic lithosphere observed today in the upper jurassic to lower cretaceous mélange of mt. kalnik, located in the sw part of the zagorje‒mid-transdanubian zone (zmtdz). poikilitic heteroadcumulate ultramafic rocks of mt. kalnik are represented by amphibole lherzolites/harzburgites and plagioclase lherzolites. both were formed by in-situ processes within a magma chamber following the general crystallization sequence of: al-chromite → mg-rich olivine → enstatite ± augite → ca-amphibole (pargasite ± edenite ± magnesiohornblende) → ca-plagioclase (an82.6-87.4). cumulate minerals are spinel and olivine as well as orthopyroxene and clinopyroxene which are usually enclosed in intercumulate phases such as amphibole and/or plagioclase that render an interstitial mesostasis. rocks’ textural characteristics, mineral crystallization order and their phase chemistry are all suggestive of low-pressure sub-solidus crystallization in an open system. the low ti content in augite and scant hfse abundances suggest the studied rocks may have formed from a depleted mantle source. in addition to the medium to high degree of partial melting of the source, the parental process that gave rise to the mt. kalnik ultramafic cumulates also included a low degree of fractional crystallization. the segregation of oxidized al-chromite and oikocrysts of pargasite and edenite in an early crystallization stage illustrates the formation of a cumulate sequence from volatile-rich magmas. these magmas usually have a high oxidation potential and are exclusively found in intra-oceanic subduction zones, predominantly in island arcs. the overall whole-rock geochemistry [e.g. (nb/la)n = 0.25-0.34; (ti/gd)n = 0.49-0.89; (th/nb)n = 5.29-8.63; (la/lu)cn = 0.57-0.68] together with a record of ca-rich plagioclase (up to an87.4) and low ti clinopyroxene (≤0.54 wt%) corroborate the supra-subduction tholeiitic nature of the magma source. ultramafic cumulates from the ophiolitic mélange of mts. kalnik and medvednica show common genetic features and geotectonic provenance. comparison with analogous ultramafic lithotypes of the north-eastern segment of the zmtdz (the szarvaskö complex, hungary), the ultramafic cumulates of mts. kalnik and medvednica portray some subtle differences that may indicate their distinctive geotectonic provenance. mts. kalnik and medvednica ultramafic cumulates represent the vestiges of a single upper jurassic intra-oceanic arc system formed in the western branch of the meliata-maliak segment of the neotethyan oceanic realm. shervais, 2001; pearce et al., 2003; pearce, 2008; bortolotti et al., 2013; saccani & tassinari, 2015). ultramafic rocks affiliated to ophiolite are commonly found in the dinarides and carpathians as a component of ophiolite complexes (e.g. balla, 1984; hovorka et al., 1985; pamić & desmons, 1989; lugović et al., 1991; majer, 1993; ivan, 2002; hoeck et al., 2006). as integral parts of an ophiolite, ultramafic cumulates emerge as slices of oceanic plates that are now observed obducted and emplaced onto passive continental plate margins. more typically, these cumulates occur in the form of fragmented allochthonous bodies (olistoliths), embedded in the chaotic rock mixture usually referred to as an ophiolitic mélange (e.g. wakabayashi & dilek, 2003; festa et al., 2010). ophiolite mélange represents a disordered tectono-sedimentary complex initially formed by tectonically activated sedimentary processes in the deep oceanic trench (accretionary wedge) developed in a forearc region in front of the leading edge of the overriding plate (raymond, 1984; festa et al., 2010). article history: manuscript received june 19, 2018 revised manuscript accepted september 07, 2018 available online october 17, 2018 keywords: ultramafic cumulates, island arc, ophiolite mélange, zagorje-mid-transdanubian zone, mt. kalnik, croatia g eo lo gi a c ro at ic a geologia croatica 71/3186 in nw croatia the outcrops of ultramafite cumulate rocks are scarce and are limited to fragmented allochthonous blocks recovered from the mélange of mts. medvednica (slovenec & lugović, 2000; lugović et al., 2007) and kalnik (fig. 1a-b and 2). these blocks contribute to the commonly named “block-in-matrix” mélange fabric, which is characteristic for dismembered ophiolitic mélanges (lugović et al., 2007; slovenec et al., 2011). the mt. kalnik mélange defines a single tectonostratigraphic unit of the larger kalnik unit (haas et al., 2000; fig. 1b). the kalnik unit consists of the lithological remnants of a discrete mesozoic (triassic-jurassic) oceanic domain that connects the dinaric-vardar ophiolites (e.g. lugović et al., 1991; pamić, 1997; pamić et al., 2002, schmid et al., 2008 and references therein), located to the southwest, with ophiolites exposed to the northeast in ne hungary (e.g. balla et al., 1983, balla, 1984; downes et al., 1990; harangi et al., 1996; aigner-torres & koller, 1999; hass & kovács, 2001; kiss et al., 2012 and references therein; sd, bü – fig. 1a) and se slovakia (e.g. hovorka et al., 1985; ivan, 2002; faryad et al., 2005 and references therein; jk – fig. 1a). the mountains of kalnik and medvednica, along with ivanščica and samoborska gora, are located at the south-western tip of the sw-ne trending zagorje-mid-transdanubian shear zone (zmtdz; pamić & tomljenović, 1998), which represents a triple junction zone between the south-eastern alps, tiszia continental block and the internal dinarides. the zone lies in the southern part of the alcapa (alpine-carpathian-pannonian) block of the intra-carpathian area in the sense of harangi et al. (1996) (fig. 1a-b). all the aforementioned croatian inselbergs are composed of preneogene heterogeneous tectonostratigraphic and tectonometamorphic units of superimposed dinaric and alpine affiliations (e.g. pamić & tomljenović, 1998; tari & pamić, 1998; haas et al., 2000; haas & kovács, 2001; pamić, 2002). finally, based on the similar tectonostratigraphic evolution, the zmtdz has been considered (after schmid et al., 2008) as an integral part of the western vardar ophiolite unit where it defines its north-westernmost segment. the goal of this research is to present for the first time the mineralogical, petrological and geochemical characteristics of cumulate ultramafic rocks from the ophiolitic mélange of mt. kalnik and to infer their petrogenesis by discussing a plausible geotectonic setting of their formation. in the future, this study will add to the existing knowledge on the geodynamic evolution of the oceanic lithosphere of the dinaridic tethys during mesozoic time by correlating our findings with analogous rocks from the neighbouring ophiolitic complexes or mélanges from the zmtdz. 2. geology of mt. kalnik a simplified geological map and stratigraphic column of mt. kalnik is shown in figure 2. its surface geology comprises neogene clastic rocks and parts of the heterogeneous ophiolitic mélange. the northern part of the mt. kalnik ophiolite mélange is thrust onto the neogene-pleistocene sedimentary succession (šimunić et al., 1982). all other contacts of the ophiolite mélange exhibit a tectonic-erosional unconformity against the youngest neogene and pleistocene sedimentary rocks (fig. 2). the central ridge of mt. kalnik is composed of palaeocene carbonate breccia thrust over neogene sedimentary rocks (šimunić et al., 1981). the common constituents of the breccia are fragments of triassic algal and stromatolithic limestone and dolomite, as well as jurassic and upper cretaceous limestone. several individual tectonic slices of early cretaceous(?) highly serpentinized mantle peridotites of island arc (ia) affinity, several hundred metres in diameter were exhumed along the mountain ridge tectonic zone (poljak, 1942; šimunić et al., 1981), accompanied by a composite slice of serpentinized lherzolites (lugović et al., 2007) that are underlain by the mass of orthoamphibolites (šegvić et al., 2016). amphibolite occurs in the form of hectometre-sized blocks placed within the ophiolitic mélange that is tectonically inserted in the palaeogene sedimentary succession. geochemical and petrological characteristics of mantle peridotites and amphibolites indicate a common tectono-metamorphic history. the mélange is predominantly composed of homogenous metre-to-hectometre-kilometre-sized ophiolitic blocks (mafic extrusives, subordinate gabbros), showing various geochemical signatures (e-, t-, n-morb, ia) consistent with their distinct geotectonic formation setting during an age span from the ladinian to the bajocian (oceanic setting), and the bathonian to the late oxfordian (suprasubduction setting; crnković et al., 1974; vrkljan, 1989; pamić, 1997; vrkljan & garašić, 2004; slovenec et al., 2011; lugović et al., 2015). however, some gabbroic blocks that appear as fault-bounded tectonic inclusions that were embedded in the mélange during ophiolite emplacement have been proved to represent evidence of back-arc cretaceous magmatism (lugović et al., 2015). two allochthonous and homogenous metre-sized blocks of ultramafic cumulates, that outcrop only rarely, are investigated in detail in this study. they have been recovered in the se part of the mt. kalnik mélange in kamešnica creek, about 1 km north of the central ridge of mt. kalnik (fig. 2). in addition to ophiolitic blocks, mélange is also composed of the metre-to-hectometre-sized olistoliths of sedimentary rocks (greywackes, minor shales, middle triassic and jurassic cherts, and scarce triassic limestones), along with blocks of non-ophiolite (intracontinental rift) originated alkali basalts (e.g. šimunić et al., 1982; slovenec et al., 2011; fig. 2). the blocks of mesozoic rocks are embedded in a predominantly sheared continent-derived pelitic to silty matrix (fig. 2). based on matrix palynomorph assemblages, the accretionary age of the kalnik unit, i.e. ophiolite mélange is defined as early callovian to late valangian (babić et al., 2002). this time interval represents a period of accumulation of lithostratigraphically diverse material in an intra-oceanic trench (slovenec et al., 2011). following the accretion, these rocks underwent emplacement onto the eastern continental margins of the adria plate in aptian to post-palaeocene time (pamić & tomljenović, 1998; pamić, 2002). there are arguments suggesting that the zmtdz was displaced by translation and rotation along the zagreb-zemplin lineament in a ne direction, finally reaching its present position during the middle miocene (pamić, 1997; tomljenović et al., 2008; fig. 1a-b). 3. analytical techniques twenty thin-sections of representative rock samples were analysed using an olympus bh-2 polarization microscope installed at the croatian geological survey (zagreb, croatia). the chemical composition of mineral phases from three samples were analysed at the institute of geosciences (university of heidelberg, germany) using a cameca sx51 electron microprobe equipped with five wavelength-dispersive spectrometers. the operating parameters included 15 kv accelerating voltage, 20 na beam current, and ~ 1 μm beam size (~ 10 μm for feldspars). counting times of 20 s on peak and 10 s on background on both sides of the peak were used for all elements. limits of detection (lod) were g eologia c roatica slovenec and šegvić: the first record of ultramafic cumulates from the mt. kalnik ophiolite mélange in the sw part of the zagorje-mid-transdanubian ... 187 calculated as the minimum concentration required to produce count rates three times higher than the square root of the background (3s; 99 wt.% degree of confidence at the lowest detection limit). natural minerals, oxides (corundum, spinel, hematite, and rutile), and silicates (albite, orthoclase, anorthite, and wollastonite) were used for calibration. the measurements relative error was less than 1%. raw data were corrected for matrix effects using the pap algorithm (pouchou & pichoir, 1984, 1985) implemented by cameca. mineral phase formula calculations were done using a software package minpet designed by linda r. richard. bulk-rock powders for chemical analyses of four samples were obtained from rock chips free of veins. the samples were analysed by icp-oes for major elements and icp-ms for all trace elements at actlab laboratories in ancaster, canada. international mafic rocks were used as standards. major element and trace element concentrations were measured with accuracy better than 1% and 5%, respectively. 4. petrography and mineral chemistry the investigated rocks in hand specimen are characterised by their black to dark green colour. they are massive and dense while breaking unevenly. sporadically, the rocks may be mottled by the pale spots of plagioclase. the texture of the analysed cumulate ultramafic rocks is granular allotriomorphic to poikilitic, while the structure is homogenous (fig. 3), which is typical for the deepest part of an ophiolite sequence (e.g. menzies, 1973; england & davies, 1973). these rocks are characterised by a network of cumulate crystals found in an immediate contact. the intercumulus space is filled by interstitial melt that has continued to produce minerals long after the previously crystallized phases have settled. this led to the development of a reaction series between mineral phases which defines a heteroadcumulate texture (wager et al., 1960; wager & brown, 1968; irvine, 1982). cumulate phases are spinel and olivine that are normally enclosed in intercumulus amphibole and/or plagioclase. both intercumulus phases define an interstitial mesostasis (fig. 3a-b). spinel represents the earliest cumulate phase that is readily hemmed in by olivine (fig. 3b and 3d). alternatively, both phases are marked by a cotectic growth (fig. 3a and 3c). orthopyroxene and clinopyroxene are rarely reported as cumuli, while more commonly they emerge along with the coarse oikocrystals of brown amphibole filling the intercumulus space and enclosing spinel and olivine (fig. 3c-d). the last intercumulus crystallization phase is plagioclase that occurs as mesostasis in the interstitial space between clinopyroxene and orthopyroxene (fig. 3b). accessory phases are leucoxene and tiny apatite reported in intercumulus plagioclase. such textural charfigure 1. (a) geotectonic sketch map of the alps, dinarides and hellenides showing the position of the zagorje–mid-transdsnubian zone (after pamić, 2000). legend: 1–external units (external dinarides and alps); 2–internal units [passive continental margin, central dinaride ophiolite belt (cdob), mirdita zone]; 3–periadriatic-sava-vardar zone including the inner dinaric ophiolite belt (idob); 4–serbo-macedonian massif; 5–pelagonides; 6–golija zone; 7–zagorje–mid-transdanubian zone; 8–panonian basin. faults: bl–balaton; pl–periadriatic; sf–sava; spf–scutari-peć; sn–sava nape; vf–vardar; zzl–zagreb-zemplin. mountains: i–ivanščica; k–kalnik; ko–kopaonik; md–medvednica; sg–samoborska gora and mts. žumberak; sd–szarvaskö-darnó; bü–bükk; jk–jaklovce. the arrow indicates mt. kalnik (b) sketch map of the structural units and major lineaments (modified after haas et al., 2000). legend: 1– austroalpine units; 2–pelso unit; 3–south alpine units and julian-savinja and south karawanken units; 4–south zala unit; 5–central slovenian and bosnian units; 6–medvednica unit; 7–kalnik unit; 8–internal dinaridic unit (vardar unit); 9–external dinaridic unit; 10–tisza mega-unit; 11–black arrow indicates mt. kalnik study area; 12–box indicates the area shown on the figure 2; bl–balaton lineament; zzl–zagreb-zemplin lineament; pl–periadriatic lineament. g eo lo gi a c ro at ic a geologia croatica 71/3188 figure 2. simplified geological map and stratigraphic column of mt. kalnik (modified after šimunić et al., 1982 and halamić, 1998). legend: 1–neogene sedimentary rocks; 2–palaeogene sedimentary rocks; 3–jurassic/early cretaceous ophiolite mélange with blocks of: 3a–basalt, 3b–gabbro, 3c–tectonite peridotite/ amphibolite, 3d–ultramafic cumulates and triassic-jurassic radiolarites, sandstones and shales (not separated on the map); 4–reverse or thrust faults; 5–normal faults; 6–discordance line, tectonic-erosion discordance; 7–quarry; 8–black arrow indicates the blocks of ultramafic cumulates in the mt. kalnik ophiolite mélange. figure 3. photomicrographs of the mt. kalnik ultramafic cumulates thin sections obtained under polarized light: (a) olivine and spinel enclosed in intercumulus amphibole (amphibole lherzolite), (b) poikilitic plagioclase fill intercumulus space and cumulus olivine serpentinization in the mesh chrysotile (plagioclase lherzolite), (c) olivine enclosed in intercumulus orthopyroxene (amphibole harzburgite) and (d) spinel enclosed in olivine and as individual cumulii within the intercumulus clinopyroxene (amphibole lherzolite). legend: amp – amphibole, cpx – clinopyroxene, ctl – chrysotile, mag – magnetite, ol – olivine, opx – orthopyroxene, pl – plagioclase, sp – spinel. g eologia c roatica slovenec and šegvić: the first record of ultramafic cumulates from the mt. kalnik ophiolite mélange in the sw part of the zagorje-mid-transdanubian ... 189 ta bl e 1. r ep re se nt at iv e ch em ic al c om po sit io ns a nd c al cu la te d m in er al fo rm ul ae o f s pi ne l, o liv in e, o rt ho py ro xe ne , c lin op yr ox en e, a m hi bo le a nd fe ld sp ar fr om th e ul tr am afi c cu m ul at es in th e m t. ka ln ik o ph io lit e m él an ge m in er al sp in el o liv in e o rt ho py ro xe ne cl in op yr ox en e am ph ib ol e fe ld sp ar sa m pl e vs k21 9/ 1 vs k21 9/ 1 vs k21 9/ 2 vs k21 9/ 2 vs k21 9/ 2 vs k21 9/ 4 vs k21 9/ 1 vs k21 9/ 1 vs k21 9/ 1 vs k21 9/ 2 vs k21 9/ 2 vs k21 9/ 4 vs k21 9/ 1 vs k21 9/ 1 vs k21 9/ 2 vs k21 9/ 2 vs k21 9/ 4 vs k21 9/ 4 an al . n o. 14 26 12 1 3 16 8 19 33 6 15 25 35 5 8 4 19 21 ro ck ty pe ahz b ahz b alh z alh z alh z plh z ahz b ahz b ahz b alh z alh z plh z ahz b ahz b alh z alh z plh z plh z si o 2 0. 02 0. 01 0. 72 39 .1 8 39 .0 9 39 .0 5 54 .3 5 54 .6 9 54 .8 5 52 .4 7 52 .2 6 51 .7 0 49 .2 4 43 .5 0 46 .1 8 52 .4 4 46 .8 0 47 .1 9 ti o 2 1. 90 1. 55 2. 25 0. 01 0. 00 0. 00 0. 30 0. 34 0. 17 0. 49 0. 54 0. 41 0. 09 2. 91 0. 54 0. 29 0. 00 0. 00 al 2o 3 15 .9 5 16 .9 1 12 .7 9 0. 03 0. 00 0. 03 1. 44 1. 45 1. 61 2. 42 2. 54 2. 67 8. 29 11 .1 7 10 .0 9 4. 83 33 .1 0 32 .9 2 cr 2o 3 36 .0 1 30 .0 4 29 .2 0 0. 00 0. 02 0. 00 0. 25 0. 28 0. 42 0. 65 0. 64 0. 74 0. 27 0. 52 0. 56 0. 22 0. 00 0. 00 fe 2o 3 13 .9 5 18 .7 2 20 .7 7 0. 00 0. 00 0. 00 1. 41 0. 32 0. 00 0. 52 1. 25 2. 53 0. 00 0. 00 0. 00 0. 00 0. 47 0. 62 fe o 23 .3 6 24 .6 6 26 .7 5 16 .4 2 16 .6 2 17 .5 3 10 .6 3 11 .3 4 11 .7 5 4. 41 4. 46 3. 63 7. 43 8. 64 7. 54 7. 29 0. 00 0. 00 m no 0. 25 0. 23 0. 32 0. 23 0. 20 0. 21 0. 29 0. 28 0. 16 0. 18 0. 18 0. 17 0. 14 0. 11 0. 10 0. 15 0. 00 0. 00 n io 0. 00 0. 25 0. 22 0. 28 0. 29 0. 29 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 m go 8. 07 6. 85 5. 93 42 .9 4 43 .4 1 42 .8 1 29 .5 2 29 .2 4 28 .6 2 17 .0 8 16 .9 3 17 .5 5 18 .9 1 15 .9 2 17 .7 9 19 .4 8 0. 00 0. 00 ca o 0. 00 0. 01 0. 06 0. 06 0. 02 0. 07 1. 31 1. 45 1. 70 21 .1 9 20 .8 1 20 .2 3 10 .8 0 10 .8 2 11 .2 9 11 .9 3 16 .9 9 17 .8 3 n a 2 o 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 01 0. 02 0. 06 0. 21 0. 32 0. 26 1. 80 2. 79 2. 01 0. 91 1. 98 1. 42 k 2 o 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 02 0. 14 0. 23 0. 08 0. 02 0. 01 h 2o 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 2. 10 2. 05 2. 07 2. 13 0. 00 0. 00 to ta l 99 .5 1 99 .2 3 99 .0 0 99 .1 4 99 .6 7 99 .9 8 99 .5 1 99 .4 1 99 .3 3 99 .6 2 99 .9 3 99 .9 0 99 .1 0 98 .5 8 98 .3 9 99 .7 3 99 .3 4 99 .9 9 si 0. 00 0 0. 00 0 0. 02 5 1. 00 0 0. 99 4 0. 99 4 1. 93 9 1. 95 3 1. 96 1 1. 92 5 1. 91 5 1. 89 4 7. 01 5 6. 36 5 6. 69 0 7. 39 6 2. 16 7 2. 17 3 ti 0. 04 7 0. 03 9 0. 05 8 0. 00 0 0. 00 0 0. 00 0 0. 00 8 0. 00 9 0. 00 4 0. 01 4 0. 01 5 0. 01 1 0. 01 0 0. 32 0 0. 05 9 0. 03 1 0. 00 0 0. 00 0 al to t 0. 62 0 0. 66 3 0. 51 4 0. 00 1 0. 00 0 0. 00 1 0. 06 1 0. 06 1 0. 06 8 0. 10 5 0. 11 0 0. 11 5 1. 39 2 1. 92 7 1. 72 3 0. 80 2 1. 80 6 1. 78 5 al iv 0. 06 0 0. 05 3 0. 03 7 0. 07 5 0. 08 5 0. 10 5 1. 10 5 1. 69 2 1. 48 2 0. 61 2 al vi 0. 00 1 0. 00 8 0. 03 1 0. 03 0 0. 02 5 0. 01 0 0. 34 2 0. 23 5 0. 24 1 0. 19 0 cr 0. 93 9 0. 79 0 0. 78 8 0. 00 0 0. 00 0 0. 00 0 0. 00 7 0. 00 8 0. 01 2 0. 01 9 0. 01 9 0. 02 2 0. 03 0 0. 06 1 0. 06 4 0. 02 4 0. 00 0 0. 00 0 fe 3+ 0. 34 6 0. 46 9 0. 53 3 0. 00 0 0. 00 0 0. 00 0 0. 03 8 0. 00 9 0. 00 0 0. 01 4 0. 03 4 0. 07 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 01 6 0. 02 1 fe 2+ 0. 64 4 0. 68 6 0. 76 3 0. 35 1 0. 35 4 0. 37 3 0. 31 7 0. 33 9 0. 35 1 0. 13 5 0. 13 7 0. 11 1 0. 88 5 1. 05 7 0. 91 4 0. 86 0 0. 00 0 0. 00 0 m n 0. 00 7 0. 00 7 0. 00 9 0. 00 5 0. 00 4 0. 00 4 0. 00 9 0. 00 9 0. 00 5 0. 00 6 0. 00 6 0. 00 5 0. 01 7 0. 01 3 0. 01 2 0. 01 8 0. 00 0 0. 00 0 n i 0. 00 0 0. 00 7 0. 00 6 0. 00 6 0. 00 6 0. 00 6 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 m g 0. 39 6 0. 33 9 0. 30 1 1. 63 5 1. 64 6 1. 62 5 1. 57 0 1. 55 7 1. 52 6 0. 93 4 0. 92 5 0. 95 9 4. 01 6 3. 47 3 3. 84 2 4. 09 5 0. 00 0 0. 00 0 ca 0. 00 0 0. 00 0 0. 00 2 0. 00 2 0. 00 1 0. 00 2 0. 05 0 0. 05 5 0. 06 5 0. 83 3 0. 81 7 0. 79 4 1. 64 8 1. 69 7 1. 75 2 1. 80 2 0. 84 3 0. 87 9 n a 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 1 0. 00 1 0. 00 4 0. 01 5 0. 02 3 0. 01 8 0. 49 7 0. 79 1 0. 56 4 0. 24 8 0. 17 7 0. 12 7 k 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 3 0. 02 7 0. 04 2 0. 01 5 0. 00 1 0. 00 1 to ta l 3. 00 0 3. 00 0 3. 00 0 2. 99 9 3. 00 5 3. 00 5 4. 00 0 4. 00 0 4. 00 0 4. 00 0 4. 00 0 4. 00 0 15 .5 15 15 .7 30 15 .6 60 15 .2 91 5. 01 1 4. 98 5 m g# 38 .1 33 .1 28 .3 82 .3 82 .3 81 .3 83 .2 82 .1 81 .3 87 .3 87 .1 89 .6 81 .9 76 .7 80 .8 82 .6 cr # 60 .2 54 .4 60 .5 10 .6 11 .4 14 .9 15 .3 14 .5 15 .7 al vi /a liv 0. 02 0. 15 0. 84 0. 40 0. 29 0. 10 0. 31 0. 14 0. 16 0. 31 an 82 .6 87 .4 w o 2. 52 2. 82 3. 35 43 .3 3 42 .5 9 40 .9 5 en 78 .9 0 79 .1 1 78 .3 6 48 .6 0 48 .2 1 49 .4 4 fs 18 .5 8 18 .0 8 18 .2 9 8. 08 9. 21 9. 60 ch em ic al c om po sit io ns in w t.% , m in er al fo rm ul ae in a to m s p er fo rm ul a un it (a pf u) a nd m od al fr ac tio ns in m ol .% . lh z = lh er zo lit e, h zb = h ar zb ur gi te ; a -, p = a m ph ib ol e o r p la gi oc la se -b ea rin g as se m bl ag e. f or m ul ae c al cu la te d on th e ba sis o f 4 o xi ge ns a nd 3 c at io ns fo r sp in el ; 4 o xy ge ns a nd f e as f eo fo r o liv in e; 4 c at io ns a nd 6 o xy ge ns fo r o rt ho py ro xe ne a nd c lin op yr ox en e; 2 3 ox yg en s a nd 1 5 ca ts e xc lu di ng k a nd n a fo r a m ph ib ol e; 8 o xy ge ns a nd to ta l f e as d iv al en t. es tim at ed h 2o co rre sp on ds 2 (o h ) p er fo rm ul ar u ni t f or a m ph ib ol e. m g# = 1 00 *( m g/ (m g+ fe 2+ )); c r# = 1 00 *( cr /(c r+ al )); a n = 10 0* ca /(c a+ n + k) . w o = ca 2s i 2o 6; en = m g 2 si 2o 6; fs = f e 2 si 2o 6. g eo lo gi a c ro at ic a geologia croatica 71/3190 ene→1–36%, amphibole→10–33%, plagioclase→0–2% and spinel”0-0.6%. based on the abundances of identified mineral phases (streckeisen, 1974), the poikilitic heteroadcumulate ultramafites of mt. kalnik are classified as amphibole lherzolite/harzburgite and, to a lesser extent, plagioclase lherzolite. acteristics are commonly reported in ophiolites and may stand for the post-cumulus crystallization of an intercumulus melt (e.g. tribuzio et al., 1995, 1999; ross & elthon, 1997). the modal composition of analysed cumulate ultramafic rocks is as follows: olivine→40–70%, orthopyroxene→5–25%, clinopyroxfigure 4. (a) classification diagrams for (a) spinel (trivalent cr–al–fe3+ ternary cation plot; stevens, 1944), (b) olivine (fe2+/(fe2++mg)–mg/(fe2++mg)) cation plot; deer et al., 1997), (c-d) pyroxene (en–wo–fs (mg2si2o6–ca2si2o6–fe2si2o6) plot; morimoto, 1988), (e) amphibole (aliv–(na+k)a plot; adopted after leake et al., 1997 and hawthorne et al., 2012), (f ) feldspar (ab-an-or plot; deer et al., 1992) from the ultramafic cumulates from the mt. kalnik ophiolite mélange. field for mineral compositions from mesozoic ultramafic cumulates from medvednica mt. ophiolite mélange (lugović et al., 2007) plotted for correlation constraints. g eologia c roatica slovenec and šegvić: the first record of ultramafic cumulates from the mt. kalnik ophiolite mélange in the sw part of the zagorje-mid-transdanubian ... 191 primary mineral phases show different degrees of alterations. olivine is partly serpentinized into reticular chrysotile (fig. 3b). within the olivine cracks one may often notice dispersed agglomerations of magnetite, which is yet another serpentinization product (fig. 3a-c). pyroxene is, along the rims, frequently uralitized or altered to chlorite, whereas plagioclase may be altered to saussurite or prehnite. cumulate fine-grained spinel represents a cumulate phase representing virtually the only remaining fresh primary phase. phase chemistry of the analysed minerals is provided in table 1. spinel is subhedral (up to 0.3 mm in size) al-chromite (fig. 4a) of uniform chemical composition that features a somewhat elevated ti content (1.55-2.25 wt%), moderate range of fe2o3 (13.01-20.77 wt%), and relatively low mg# (28.3-38.1). the chromium number is relatively high (54.4-60.5) while fe3+# is elevated (18.1-29.1), which is a consequence of an oxidizing environment. subhedral to subrounded unzoned olivine (up to 1.5 mm in size) ranges in composition from fo81 to fo83 showing a chrysolite composition (fig. 4b) due to its high mg# (81.3-82.3) and low content of cao (<0.08 wt%), while the content of nio (0.28-0.29 wt%) is characteristic for olivine from crustal peridotite (leblanc et al., 1984). orthopyroxene (up to 3 mm in size) is enstatite (wo1.1-3.4en78.4-80.2fs18.1-18.8; fig. 4c) with mg# values between 81.3-83.2 whereas the content of al2o3 is relatively high (1.44-1.61 wt%). similar mg# of orthopyroxene and olivine reported in the portion of analysed rocks are presumably a result of their common formation as liquidus phases (table 1). clinopyroxene (up to 2.5 mm in size) has been classified as mg-rich augite (wo40.9-43.3en48.2-49.4fs8.1-9.6; fig. 4d). it has a relatively high mg# (87.1-89.6), moderately low content of al2o3 (<2.68 wt%), very low content of tio2 (<0.55 wt%) and low values of alvi/aliv ratio (0.10-0.40). pale brown and poorly pleochroic igneous amphibole (up to 6.5 mm in size) corresponds to pargasite and edenite with mg# between 76.7 and 80.8. compared to late magmatic magnesiohornblende and secondary actinolite and tremolite analysed amphibole has elevated values of tio2 (0.542.91 wt%), al2o3 (10.09-11.17 wt%), na2o (2.01-2.79 wt%) and k2o (0.14-0.23 wt%) (fig. 4e; table 1). relict plagioclase (up to 2 mm in size) in metastasis shows a homogenous composition an82.6-87.4 (fig. 4f; table 1). 5. bulk rock chemical composition chemical composition of the ultramafic cumulates from mt. kalnik is given in table 2. the analysed rocks underwent a deuteric and sea-floor hydrothermal alteration which led to an increase in the loss on ignition (loi £ 7.00 wt%). however, the preserved magmatic texture and only minor chemical disturbances of the major element content do not exhibit an appreciable impact on the original rocks’ chemistry. the ultramafic cumulate nature of the analysed rocks may be clearly inferred from the cao–mgo– al2o3 classification diagram (fig. 5a). they are characterised by low contents of mgo (£ 25.16 wt%) and tio2 (£ 0.31 wt%), which defines the analysed cumulates as low ti rocks (fig. 5b). the contents of fe2o3total and ni are elevated (13.86-15.96 wt% and 11211290 ppm, respectively), while the mg# is moderately high (75.378.4). a low content of sio2 (37.06-40.63 wt%) is a typical feature of analysed intrusives suggesting their cumulate origin. highfield strength elements (hfse; ti, p, ta, nb, y and th) as well as rare earth elements (ree) appeared to be relatively immobile during alteration. they maintained the typical igneous concentration levels and characteristic ratios (e.g. zr/hf = 41-44; ti/zr = 49-87; nb/y = 0.02-0.03; sm/nd = 0.3-0.4). conversely, the large ion lithophile elements (lile) showed a high degree of post-magmatic mobility and are therefore considered unsuitable for petrogenetic and geotectonic consideration. the multi-element abundance patterns normalised to nmorb are displayed in fig. 6a, while the chondrite-normalised ree patterns are given in fig. 6b. all rocks display a lile enrichment which is consistent with post-magmatic alterations. normalised patterns for a range from la to lu are flat being at 0.2 to 0.6 times relative to n-morb. a very low content of incompatible elements in cumulate ultramafites may actually reflect their cumulate origin (saunders et al., 1980; meyer et al., 1989). additionally, all analysed samples possess pronounced figure 5. discrimination diagrams for ultramafic cumulates from the mt. kalnik ophiolite mélange. (a) cao–mgo–al2o3 diagram (coleman, 1977); (b) tio2–feotot/ (feoto+mgo) diagram (serri, 1981). field for mesozoic ultramafic cumulates from medvednica mt. ophiolite mélange (lugović et al., 2007) plotted for correlation constraints. g eo lo gi a c ro at ic a geologia croatica 71/3192 negative anomalies of the nb-ta pair and ti [(nb/la)n = 0.250.34; (ti/gd)n = 0.49-0.89]. a positive anomaly of sr in plagioclase lherzolite may be indicative of plagioclase fractionation. all analysed cumulates show similar chondrite-normalised ree patterns at different relative concentration levels. the ree patterns are characterised by nearly flat heavy rare earth elements (hree) profiles [(tb/lu)cn = 0.81-1.09] at 2.1-6.3 times relative to chondrite, whereas the light rare earth elements (lree) are found to be slightly depleted compared to hree [(la/lu)cn = 0.57-0.68]. only plagioclase lherzolite shows a faint negative eu anomaly (eu/eu* = 0.92), which is typical for the minor accumulation of plagioclase. relative depletion of lree with regard to hree defines a tholeiitic affinity of cumulate ultramafites from the ophiolite mélange of mt. kalnik (fig. 6b). 6. discussion and conclusions fragments (i.e., blocks) of cumulate ultramafic rocks are the rarest member of the mesozoic oceanic lithosphere documented in the ophiolitic mélange of mt. kalinik (fig. 2). these metre-sized olistoliths originated from deep portions of oceanic crust and predominantly account for amphibole lherzolite and, to a lesser extent, amphibole harzburgite and plagioclase lherzolite. a lack of cumulate “layered” structures may suggest that the analysed rocks are not typical cumulates, and yet, the occurrence of heteroadcumulate texture visibly demonstrates the prevalence of cumulate processes at the time of formation of the mt. kalnik ophiolitic sequence. cumulate ultramafites of mt. kalnik were formed in situ via crystallization in the magma chamber (campbell, 1978, 1987). petrographic evidence suggests the following general crystallization order: al-chromite → mg-rich olivine (chrysolite) → enstatite ± augite → ca-amphibole (pargasite ± edenite ± magnesiohornblende) → ca-plagioclase (bytownite) (fig. 3). spinel and olivine are the most common cumulate phases while the post-cumulate minerals are pyroxene, amphibole and plagioclase. analysed rocks define a trend which is in accordance with the progressive removal of cumulate phases from the magma. coarse oikocrysts of amphibole were formed from a magma that represents an intercumulus magmatic residuum. amphibole frequently encloses other minerals. the crystallization of amphibole must have been sluggish thus enabling the development of several crystallization centres which ultimately gave rise to the formation of large poikilitic crystals of amphibole (fig. 3a; wager & brown, 1968). primary minerals’ phase chemistry devoid of cryptic zoning clearly indicates that the analysed cumulate ultramafites were formed in an open crystallization system of a shallow magma chamber (e.g. ariskin & yaroshevsky, 2006; holness & winnpeny, 2009; latypov, 2009). mineral crystallization order along with the low alvi/aliv (≤0.8) ratio in augite are typical characteristics of moderately low-pressure fractional crystallization (aoki & kushiro, 1968; wass, 1979; serri & saitta, 1980; shiffman & lofgren, 1982). crystallization at moderately low pressures promoted an early separation of ti oxides and hydrous silicates (i.e., chromite and pargasite/ edenite; python & ceuleneer, 2003; liu et al., 2010; krawczynski et al., 2012). this is in line with pressure values derived from augite composition (geobarometer after nimis & ulmer, 1998; nimis, 1999), suggesting crystallization pressures between 0.6 and 0.9 (±0.2) gpa. in the graphic geothermometer of lindsley (1983) analysed augite yielded maximum crystallization temperatures of between 950 and 1030 (±30) ºc, consistent with sub-solidus conditions. mineralogical and textural characteristics of mt. kalnik poikilitic and heteroadcumulate peridotites discussed herein permit the inference that their primary mineral assemblage was formed through relatively fast crystallization (except oikocrysts of amphibole) and accumulation at subsolidus temperatures. the chemistry of olivine (fo8279; cao ~ 0.07 wt% and ni ~ 2278 ppm) is indicative of fractional crystallization of relatively primitive melts (e.g. stormer, 1973; larrea et al., 2014). the degree of fractionation was, however, relatively low (la/yb = 0.9-1.0, mg# = 75.3-78.4) which suggests the process of partial melting as parental to the formation of a primitive melt that later yielded the magma to be fractionated and produce the mt. kalnik cumulates. jaques & green (1980) demonstrated that the first mineral phase formed after olivine in a cumulate sequence is determined by the degree of partial melting. in the investigated rocks the crystallization series olivine → orthopyroxene ± clinopyroxene was established figure 6. n-morb-normalised multielement patterns (sun & mcdonough, 1989); (b) ree-normalized patterns (taylor & mclennan, 1985) for ultramafic cumulates from the mt. kalnik ophiolite mélange. field for mesozoic ultramafic cumulates from medvednica mt. ophiolite mélange (lugović et al., 2007) and from szarvaskö complex (ne hungary) (downes et al., 1990; aigner-torres & koller, 1990) plotted for correlation constraints. g eologia c roatica slovenec and šegvić: the first record of ultramafic cumulates from the mt. kalnik ophiolite mélange in the sw part of the zagorje-mid-transdanubian ... 193 which according to jaques & green (1980) corresponds to medium to high degrees of partial melting of parental magma which leaves a mantle residue represented by harzburgite. a very low hfse content (0.2 to 0.6 times relative to n-morb) as well as a slight lree depletion relative to hree, along with a very low content of ti in clinopyroxene indicate the origin of cumulates from a depleted source (pearce & norry, 1979; beccaluva et al., 1989; fig. 5b and fig. 6). chemistry of amphibole reflects a relatively complex process of the formation of cumulate ultramafite from mt. kalnik. namely, the amphibole is characterised by a peculiar compositional trend (i.e. “pargasitic trend”, fig. 4e), indicative of a multifold formation sequence that firstly includes the crystallization of the primary pargasitic phase. further cooling under magmaticsubmagmatic conditions enhanced deuteric alteration of the primary cumulate assemblage giving rise to the appearance of magnesiohornblende. finally, post-magmatic processes related to sea-floor hydrothermal activity facilitated the formation of secondary actinolite/tremolite. the presence of hydrous primary amphibole (pargasite) in the studied rocks indicates crystallization of the ophiolite sequence from volatile-rich magmas characterised by a high oxidation potential. such magmas are exclusively found in the intra-oceanic subduction zones, predominantly in island arcs, where hydrous mantle melting was facilitated by the addition of volatiles from the subducting slab (conrad & kay, 1984; debari & coleman, 1989; tatsumi & eggins, 1995; koepke & seidel, 2004; kocak et al., 2005). formation of amphibole-rich ultramafic cumulates in arc settings has been studied well, both empirically and experimentally (e.g. larocque & canil, 2010; krawczynski et figure 7. discrimination diagrams for ultramafic cumulates from the mt. kalnik ophiolite mélange. (a) cr2o3–al2o3 diagram for spinels (franz & wirth, 2000). (b) 100*(mg/(mg+fe2+) (mg#) vs. 100*(cr/(cr+al) (cr#) diagram for spinels. (c) na2o+k2o–mgo–feotot diagram (bread, 1986). data for morb, fore-arc and arc related spinel fields are from kepezhinskas et al. (1993) and reference therein. field for mesozoic ultramafic cumulates from medvednica mt. ophiolite mélange (lugović et al., 2007) plotted for correlation constraints. g eo lo gi a c ro at ic a geologia croatica 71/3194 al., 2012). their occurrence is commonly linked to the middle to lower crust of volcanic arcs (davidson et al., 2007). low content of tio2 (≤0.54 wt%) in augite and the presence of ca-rich plagioclase is yet another characteristic of magmatic arc (e.g. beard, 1986; debari & coleman, 1989; parlak et al., 1996; ilbeyli, 2008) and forearc (ballantyne, 1992) settings in which analysed cumulates could have probably originated during the upper jurassic. however, chromite is still considered as a most reliable indicator of the geotectonic affiliation of intrusive parts of a cumulate sequence (e.g. kamenetsky et al., 2001). chemistry of al-chromite thus strongly suggests that analysed cumulates originated in an island-arc setting making a clear distinction from a possible forearc geotectonic setting (fig. 7a-b). this line of reasoning is further corroborated by cumulates’ major element content (na2o+k2o–mgo–feotot diagram; fig. 7c), along with the negative ta-nb pair and ti anomalies and relatively uniform depletion of hfse and ree in multi-elemental plots normalised to n-morb (fig. 6a). these features are typical for suprasubduction zone (ssz) magmas and therefore clearly indicate the influence of the subduction component. taking into account that mesozoic (probably upper jurassic) ultramafite cumulates are rarely encountered in the ophiolite complexes/mélanges of the zmtdz there is a paucity of correlative mineralogical, petrologic and geochemical data. in addition to ultramafic olistoliths from the ophiolitic mélange of mts. kalnik and medvednica (lugović et al., 2007), similar ultramafic lithotypes were reported at the north-easternmost part of the zmtdz in the szarvaskö magmatic complex (mts. bükk) in hungary (balla et al., 1983; balla, 1984; kubovics, 1984; kubovics & bilik, 1984; downes et al., 1990; harangi et al., 1996; józsa, 1999; aigner-torres & koller, 1999; fig. 1a-b). common characteristics of ultramafite cumulates from the three ophiolite complexes/mélanges is the presence of igneous intercumulus oikocrysts of amphibole, an early crystallization of ti rich non-silicate minerals, low-grade (prehnite-pumpellyite facies) alteration overprint that took place during the alpine orogeny and under a rather high oxidation state. the sequence of crystallization and mineral phase chemistry as well as rock bulk chemistry is very similar when comparing the cumulate lithotypes from the ophiolite mélange of mts. kalnik and medvednica (fig. 4). in general, ultramafic cumulates from all three localities within the zmtdz show similar normalised concentration patterns at different fractionation levels (fig. 6), which point to a common origin but different degrees of evolution of the parental magma. nonetheless, the absence of the negative ta-nb pair and ti anomalies in ultramafites from the szarvaskö complex and fractionation from an evolved basic melt distinguish these rocks (wherlite) from the cumulates of mts. kalnik and medvednica whose geochemical particularities clearly testify to their formation in a supra-subduction arc setting (fig. 6 and 7). considering the discussion presented herein and previous literature on the fragments of oceanic lithosphere from the ophiolite mélange of mts. kalnik and medvednica (lugović et al., 2007; slovenec & lugović, 2008; slovenec et al., 2011; lugović et al., 2015) we suggest that ultramafic cumulates of the sw segment of the zmtdz originated from a single mesozoic (most probably upper jurassic) oceanic domain. subsequently, these rocks formed part of an intra-oceanic arc system formed in the western branch of the meliata-maliak segment of the tethyan oceanic realm. such a geodynamic scenario conforms well to the geotectonic reconstruction suggested by stampfli & borel (2002, 2004). acknowledgement this work contributes to the scientific project “mesozoic magmatic, mantle and pyroclastic rocks of north-western croatia (grant no. 181-1951126-1141 to da. s.)” carried out under the support of the croatian ministry of science, education and sport. we thank b. lugović and h-p. meyer for microprobe facilities and i. fin for excellent polished thin sections. finally, the critical comments and constructive reviews by m. putiš and an anonymous reviewer contributed significantly to the quality of this paper. table 2. chemical compositions of ultramafic cumulates in the mt. kalnik ophiolite mélange. sample vsk-219/1 vsk-219/2 vsk-219/3 vsk-219/4 rock type a-hzb a-lhz a-lhz p-lhz sio2 40.64 40.15 38.43 37.06 tio2 0.31 0.20 0.29 0.22 al2o3 6.15 5.85 4.96 7.21 fe2o3total 13.86 14.28 15.82 15.96 mno 0.16 0.11 0.14 0.18 mgo 24.49 23.05 25.16 23.92 cao 6.26 10.61 9.79 11.51 na2o 0.90 0.28 0.46 0.33 k2o 0.01 0.02 0.01 0.03 p2o5 0.06 0.02 0.04 0.03 loi 7.00 5.36 4.89 3.42 total 99.84 99.93 99.99 99.87 mg# 78.4 77.3 76.2 75.3 cs 0.1 0.6 0.8 0.2 rb 1 2 1 3 ba 23 32 18 28 th 0.09 0.07 0.09 0.08 ta 0.02 0.01 0.02 0.01 nb 0.33 0.18 0.31 0.18 sr 45 22 33 35 zr 38 15 29 18 hf 0.92 0.34 0.69 0.43 y 15.1 5.2 8.9 6.3 sc 23 22 18 24 v 125 129 121 131 cr 1800 1821 1932 1754 co 89 68 72 76 ni 1290 1260 1210 1121 la 1.42 0.58 0.99 0.65 ce 4.05 1.63 2.71 1.79 pr 0.62 0.24 0.46 0.29 nd 3.74 1.38 2.41 1.65 sm 1.23 0.46 0.85 0.55 eu 0.521 0.172 0.311 0.188 gd 1.83 0.65 1.12 0.71 tb 0.38 0.13 0.24 0.15 dy 2.41 0.87 1.51 1.01 ho 0.53 0.21 0.36 0.23 er 1.62 0.68 1.10 0.79 tm 0.228 0.099 0.155 0.110 yb 1.52 0.64 0.99 0.76 lu 0.229 0.106 0.151 0.115 major elements in wt.%, trace elements in ppm. loi = loss on ignition at 1100 oc. lhz = lherzolite, hzb = harzburgite; a-, p= amphiboleor plagioclase-bearing assemblage. mg# = 100*molar (mgo/(mgo+feototal)). g eologia c roatica slovenec and šegvić: the first record of ultramafic cumulates from the mt. kalnik ophiolite mélange in the sw part of the zagorje-mid-transdanubian ... 195 references aigner-torres, m. & koller, f. (1999): nature of the magma source of the szarvaskö complex (ne hungary): petrological and geochemical constraints.– ofioliti, 24, 1–12. ariskin, a.a. & yaroshevsky, a.a. (2006): crystallization differentiation of intrusive magmatic melt: development of a convectionaccumulation model.– geochemistry international, 44, 72–93. doi: 10.1134/s0016702906010083 aoki, k. & kushiro, i. (1968): some clinopyroxenes from ultramafic inclusions in dreiser weiher, eifel.– contr. mineral. petrol., 21, 743–749. doi: 10.1007/ bf00399694 babić, lj., hochuli, p.a. & zupanič, j. (2002): the jurassic ophiolitic mélange in the ne dinarides: dating, internal structure and geotectonic implications.– eclogae geologicae helvetiae, 95, 263–257. bagci, u. (2013): the geochemistry and petrology of the ophiolitic rocks from the kahramanmaras region southern turkey.– turkish j. earth sci., 22, 536–562. doi: 10.3906/year-1203-1. balla, z. (1984): the north hungarian mesozoic mafics and ultramafics.– acta geol. hung., 27, 341–357. balla, z., hovorka, d., kuzmin, m. & vinogradov, v. (1983): mesozoic ophiolites of the bükk mountains (north hungary).– ofioliti, 8, 5–45. ballantyne, p. (1992): petrology and geochemistry of the plutonic rocks of the halmahera ophiolite, eastern indonesia, an analogue of modern oceanic forearcs.– in: l.m. parson, b.j. murton & p. browning (eds.): ophiolites and their modern oceanic analogues.– geol. soc. spec. publ., 60, 179–202. doi: 10.1144/ gsl.sp.1992.060.01.11 beccaluva, l., macciotta, g., piccardo, g.b. & zeda, o. (1989): clinopyroxene composition of ophiolite basalts as petrogenetic indicator.– chemical geology, 77, 165–182. doi: 10.1016/0009-2541(89)90073-9 bortolotti, v. & principi, g. (2005): tethyan ophiolites and pangea break-up.– island arc, 14, 442–470. doi: 10.1111/j.1440-1738.2005.00478.x bortolotti, v., chiari, m., marroni, m., pandolfi, l., principi, g., saccani, e. (2013): the geodynamic evolution of the ophiolites from albania and greece, dinaric-hellenic belt: one, two, or more oceanic basins?– int. j. earth sci., 102, 783–811. doi: 10.1007/s00531-012-0835-7. bread, j.s. (1986): characteristic mineralogy of arc-related cumulate gabbros: implications for the tectonic setting of gabbroic plutons and for andesite genesis.– geology, 14, 848–851. doi: 10.1130/0091-7613(1986)14%3c848:cmoacg%3e2. 0.co;2 campbell, i.h. (1978): some problems with the cumulus theory.– lithos, 11, 311– 323. doi: 10.1016/0024-4937(78)90038-5 campbell, i.h. (1987): distribution of orthocumulate textures in the imberlana intrusion.– j. geol., 95, 35–54. coleman, r.g. (1977): ophiolites. springer-verlag, berlin, 229 p. doi: 10.1007/9783-642-66673-5 coleman, r.g. (1981): tectonic setting for ophiolite obduction in oman.– j. geophys. res., 86, 2497–2508. doi: 10.1029/jb086ib04p02497 conrad, w.k. & kay, r.w. (1984): ultramafic and mafic inclusions from adak islands: crystallization history, and implications for the nature of primary magmas and crustal evolution in the aleutian arc.– j. petrol., 25, 88–125. doi: 10.1093/petrology/25.1.88 crnković, b., babić, v. & tomašić, i. (1974): the gabbro of hruškovec near ljubeščica on mount kalnik (northern croatia).– geološki vjesnik, 27, 153–171 (in croatian with english summary). davidson, j., turner, s., handley, h., macpherson, c. & dosseto, a., (2007): amphibole ‘‘sponge’’ in arc crust?– geology, 35, 787–790. debari, s.m. & coleman, r.g. (1989): examination of deep levels of an island arc: evidence from the tonsina ultramafic-mafic assemblage, tonsina, alaska.– j. geophys. res., 94, 4373–4391. doi: 10.1029/jb094ib04p04373 deer, w.a., howie, r.a. & zussman, j. (1992): an introduction to the rock forming minerals, 2nd ed., harlow, longman, 696 p. deer, w.a., howie, r.a. & zussman, j. (1997): rock-forming minerals; vol. 1b. alden press, osney, mead, oxford, 629 p. dilek, y. (2003): ophiolite pulses, mantle plumes and orog eny.– geol. soc. lond. spec. publ., 218, 9–19. doi: 10.1144/gsl.sp.2003.218.01.02. dilek, y. & furnes, h. (2011): ophiolite genesis and global tectonics: geochemical and tectonic fingerprinting of ancient oceanic lithosphere.– geol. soc. am. bull., 123, 387–411. dilek, y. & furnes, h. (2014): ophiolites and their origins.– elements, 10, 93–100. doi: 10.2113/gselements.10.2.93 downes, h., pantó, g.y., árkai, p. & thirlwall, m.f. (1990): petrology and geochemistry of mesozoic igneous rock, bükk mountains.– lithos, 24, 201–215. doi: 10.1016/0024-4937(90)90032-v england, r.n. & davies, h.l. (1973): mineralogy of ultramafic cumulates and tectonites from eastern papua.– earth planet. lett., 17, 416–425. doi: 10.1016/0012821x(73)90210-0 faryad, s.w., spišiak, j., horvát, p., hovorka, d., dianiška, i. & józsa, s. (2005): petrological and geochemical features of the meliata mafic rocks from the sutured triassic oceanic basin, western carpathians.– ofioliti, 30, 27–35. festa, a., pini, g.a., dilek, y. & codegone, j. (2010): mélanges and mélangeforming processes: a historical overview and new concepts.– in: dilek, y. (ed.): alpine concept in geology. international geology review, 52, 1040–1105. franz, l. & wirth, r. (2000): spinel inclusions in olivine of peridotite xenoliths from tubaf seamount (bismarck archipelago/papua new guinea): evidence for the thermal and tectonic evolution of the oceanic lithosphere.– contrib. mineral. petrol., 140, 283–295. doi: 10.1007/s004100000188 haas, j., mioč, p., pamić, j., tomljenović, b., árkai, p., bérczi-makk, a., koroknai, b., kovács, s. & r-felgenhauer, e. (2000): complex structural pattern of the alpine-dinaridic pannonian triple junction.– int. j. earth sci., 89, 377–389. doi: 10.1007/s005310000093 haas, j. & kovács, s. (2001): the dinaridic-alpine connection – as seen from hungary.– acta geol. hung., 44, 345–362. halamić, j. (1998): lithostratigraphy of jurassic and cretaceous sediments with ophiolites from the mts. medvednica, kalnik and ivanščica.– phd thesis, university of zagreb, zagreb, 188 p. (in croatian with english summary). harangi, sz., szabó, cs., józsa, s., szoldán, zs., árva-sós, e., balla, m. & kubovics, i. (1996): mesozoic igneous suites in hungary: implications for genesis and tectonic setting in the northwestern part of tethys.– int. geol. rev., 38, 336–360. doi: 10.1080/00206819709465339 hawthorne, f.c., oberti, r., harlow, g.e., maresch, w.v., martin, r.f., schumacher, j.c. & welch, m.d. (2012): nomenclature of the amphibole supergroup.– american mineralogist, 9, 2031–2048. doi: 10.2138/am.2012.4276 hoeck, v., ionescu, c. & koller, f. (2006): mesozoic ophiolites in the dinarides and the carpathians: a review.– acta mineralogica-petrographica, abstract series, 5, 39–41. holness, m.b. & winpenny, b. (2009): the unit 12 allivalite, eastern layered intrusion, isle of rum: a textural and geochemical study of an open-system magma chamber.– geol. mag., 146, 437–450. doi:10.1017/s0016756808005797. hovorka, d., jaroš, j., kratochvíl, m., reichwalder, p., rojkovič, i., spišiak, j. & turanová, l. (1985): ultramafic rocks of the western carpathians, czechoslovakia.– geol. inst. dionýz štúr, bratislava, 1–258. huot, f. & maury, r.c. (2002): the round mountain serpentinite mélange, northern coast ranges of california: an association of backarc and arc-related tectonic units.– gsa bull., 114, 109–123. ilbely, n. (2008): geochemical comparison of ultramafic-mafic cumulate rocks from the central anatolian ophiolites, turkey.– int. geol. rev., 50, 810–825. doi: 10.2747/0020-6814.50.9.810 irvine, t.n. (1982): terminology for layered intrusions.– j. petrol., 23, 127–162. doi: 10.1093/petrology/23.2.127-a ivan, p. (2002): relicts of the meliata ocean crust: geodynamic implications of mineralogical, petrological and geochemical proxies.– geol. carpathica, 53, 245–256. jaques, a. & green, d.h. (1980): anhydrous melting of peridotite at 0-15 kb pressure and the genesis of tholeiitic basalts.– contrib. mineral. petrol., 73, 287–310. doi: 10.1007/bf00381447 józsa, s. (1999): petrological and geochemical study of the darnó hill ocean floor magmatic rocks.– phd thesis, elte, budapest, 173 p. (in hungarian with english summary). kamenetsky, v.s., crawford, a.j. & meffre, s. (2001): factors controlling chemistry of magmatic spinel: an empirical study of associated olivine, cr-spinel and melt inclusions from primitive rocks.– j. petrology, 42, 655–671. doi: 10.1093/ petrology/42.4.655 kepezhinskas, p.k., taylor, r.n. & tanaka, h. (1993): geochemistry of plutonic spinels from the north kamchatka arc: comparison with spinels from other tectonic settings.– mineral. mag., 57, 575–589. doi: 10.1180/minmag.1993.057.389.02 kiss, g., molnár, f., palinkaš, l., kovács, s. & hrvatović, h. (2012): correlation of triassic advanced rifting-related neotethyan submarine basaltic volcanism of the darnó unit (ne-hungary) with some dinaridic and hellenidic occurrences on the basis of volcanological, fluid–rock interaction, and geochemical characteristics.– int. j. earth sci., 101, 1503–1521. kocak, k., isik, f., arslan, m. & zedef, v. (2005): petrological and source region characteristics of ophiolitic hornblende gabbros from the aksarav and kavseri regions, central anatolian crystalline complex, turkey.– j. asian earth sci., 25, 883–891. koepke, j. & seidel, e. (2004): hornblendites within ophiolites of crete, greece: evidence for amphibole-rich cumulates derived from an iron-rich tholeiitic melt.– ofioliti, 29, 159–175. krawczynski, m., grove, t. & behrens, h. (2012): amphibole stability in primitive arc magmas: effects of temperature, h2o content, and oxygen fugacity.– contrib. mineral. petrol., 164, 317–339. doi: 10.1007/s00410-012-0740-x kubovics, i. (1984): on the petrogenesis of the north hungarian basic-ultrabasic magmatic rocks.– acta geol. hung., 27, 163–189. g eo lo gi a c ro at ic a geologia croatica 71/3196 kubovics, i. & bilik, i. (1984): comparative investigation of the hungarian mesozoic basic-ultrabasic and some ophiolitic magmatic rocks in the alp-carpathian chain.– acta geol. hung., 27, 321–339. larocque, j. & canil, d. (2010): the role of amphibole in the evolution of arc magmas and crust: the case from the jurassic bonanza arc section, vancouver island, canada.– contrib. mineral. petrol., 159, 475–492. doi: 10.1007/s00410-0090436-z larrea, p., galé, c., ubide, t., widom, e., lago, m. & frança, z. (2014): magmatic evolution of graciosa (azores, portugal).– j. petrol., 55, 2125–2154. doi:10.1093/petrology/egu052. latypov, r. (2009): testing the validity of the petrological hypothesis “no phenocrysts, no post-emplacement differentiation”.– j. petrol., 50, 1047–1069. doi:10.1093/petrology/egp031. leake, b.e. et al. (1997): nomenclature of amphiboles: report of the subcommittee on amphiboles of the international mineralogical association, commission on new minerals and mineral names.– canadian mineralogist, 35, 219–246. leblanc, m., dupuy, c. & merlet, c. (1984): nickel content of olivine as a discriminatory factor between tectonite and cumulate peridotite in ophiolites.– sci. géol. bull., 37, 131–135. doi: 10.3406/sgeol.1984.1659 lindsley, d.h. (1983): pyroxene thermometry.– amer. mineralogist, 68, 477–493. liu, c.z., wu, f.y., wilde, s.a., yu, l.j. & li, j.l. (2010): anorthitic plagioclase and pargasitic amphibole in mantle peridotites from the yungbwa ophiolite (southwestern tibetan plateau) formed by hydrous melt metasomatism.– lithos, 114, 413–422. doi: 10.1016/j.lithos.2009.10.008 lugović, b., altherr, r., raczek, i., hofmann, a.w. & majer, v. (1991): geochemistry of peridotites and mafic igneous rocks from the central dinaric ophiolite belt, yugoslavia.– contrib. mineral. petrol., 106, 201–216. doi: 10.1007/ bf00306434 lugović, b., slovenec, da., halamić, j. & altherr, r. (2007): petrology, geochemistry and geotectonic affinity of the mesozoic ultramafic rocks from the southwesternmost mid-transdanubian zone in croatia.– geol. carpathica, 58, 511–530. lugović, b., slovenec, d., schuster, r., schwarz, w.h. & horvat, m. (2015): petrology, geochemistry and tectono-magmatic affinity of gabbroic olistoliths from the ophiolite mélange in the nw dinaric-vardar ophiolite zone (mts. kalnik and ivanščica, north croatia).– geol. croatica, 68/1, 25–49. doi. org/10.4154/gc.2015.03. majer, v. (1993): ophiolite complex of the banija and pokuplje region in croatia and mt. pastirevo in nortwestern bosnia.– acta geol. hazu, 23, 39–84 (in croatian with english summary). menzies, m. (1973): mineralogy and partial melt textures within an ultramafic-mafic body, greece.– contrib. mineral. petrol., 42, 273–285. doi: 10.1007/bf00372606 meyer, p.s., dick, j.b. & thompson, g. (1989): cumulate gabbros from the southwest indian ridge, 54os-7o16´ e: implications for magmatic processes at a slow spreading ridge.– contrib. mineral. petrol., 103, 44–63. moores, e.m. & jackson, e.d. (1974): ophiolites and oceanic crust.– nature, 250, 136–139. doi: 10.1038/250136a0 morimoto, n. (1988): nomenclature of pyroxenes.– schweiz. mineral. petrogr. mitteil., 68, 95–111. nimis, p. (1999): clinopyroxene geobarometry of magmatic rocks. part 2. structural geobarometers for basic to acid, tholeiitic and mildly alkaline magmatic systems.– contrib. mineral. petrol., 135, 62–74. doi: 10.1007/s004100050498 nimis, p. & ulmer, p. (1998): clinopyroxene geobarometry of magmatic rocks part 1: an expanded structural geobarometer for anhydrous and hydrous, basic and ultrabasic systems.– contrib. mineral. petrol., 133, 122–135. pamić, j. (1997): the northwesternmost outcrops of the dinaridic ophiolites: a case study of the mt. kalnik (north croatia).– acta geol. hung., 40, 37–56. pamić, j. (2000): the periadriatic-sava-vardar suture zone.– in: i. vlahović & r. biondić (eds.): 2nd croatian geological congress proceedings. institute of geology, zagreb, 333–337 (in croatian with english summary). pamić, j. (2002): the sava-vardar zone of the dinarides and hellenides versus the vardar ocean.– eclogae geologicae helvetiae, 95, 99–113. pamić, j. & desmons, j. (1989): a complete ophiolite sequence in rzav, area of zlatibor and varda ultramafic massifs, the dinaride ophiolite zone.– ofioliti, 14, 13–32. pamić, j. & tomljenović, b. (1998): basic geological data on the croatian part of the mid-transdanubian zone as exemplified by mt. medvednica located along the zagreb-zemplen fault zone.– acta geol. hung., 41, 389–400. pamić, j., tomljenović, b. & balen, d. (2002): geodynamic and petrogenetic evolution of alpine ophiolites from the central and nw dinarides: an overview.– lithos, 65, 113–142. parlak, o., delaloye, m. & bíngöl, e. (1996): mineral chemistry of ultramafic and mafic cumulates as an indicator of the arc-related origin of the mersín ophiolite (southern turkey).– geol. rundsch., 85, 647–661. parlak, o., höck, v. & delaloye, m. (2002): the suprasubduction zone poznatikersanti ophiolite, southern turkey: evidence for high-pressure crystal fractionation of ultramafic cumulates.– lithos, 65, 205–224. pearce, j.a. (2008): geochemical fingerprinting of oceanic basalts with applications to ophiolite classification and the search for archean oceanic crust.– lithos, 100, 14–48. doi:10.1016/j.lithos.2007.06.016. pearce, j.a. & norry, m.j. (1979): petrogenetic implications of ti, zr, y, and nb variations in volcanic rocks.– contrib. mineral. petrol., 69, 33–47. doi: 10.1007/ bf00375192 pearce, j.a. (2003): subduction zone ophiolites. in dilek, y., and newcomb, s., eds. ophiolite concept and the evolution of geological thought.– geol. soc. am. spec. pap., 373, 269–294. python, m. & ceuleneer, g. (2003): nature and distribution of dykes and related melt migration structures in the mantle section of the oman ophiolite.– geochem., geophys., geosyst., 4., 1–34. doi: 10.1029/2002gc000354 poljak, j. (1942): a contribution to the knowledge of geology of the mt. kalnik.– vjestnik hrvatskog državnog geoložkog zavoda i hrvatskog državnog geoložkog muzeja, 1, 53–92 (in croatian with german summary). pouchou, j.l. & pichoir, f. (1984): a new model for quantitative analyses. i. application to the analysis of homogeneous samples.– la recherche aérospatiale, 3, 13–38. pouchou, j.l. & pichoir, f. (1985): “pap” (φ-ρ-z) correction procedure for improved quantitative microanalysis.– in: armstrong, j.t. (ed.): microbeam analysis, san francisco, california, usa: san francisco press, 104–106. raymond, l.a. (1984): classification of melanges. in: l.a. raymond (ed.): mélanges: their nature, origin, and significance.– geol. soc. of amer. spec. paper, 198, 7–20. doi: 10.1130/spe198-p7 ross, k. & elthon, d. (1997): cumulus and postcumulus crystallization in the ocean crust: majorand trace-element geochemistry of leg 153 gabbroic rocks.– in: karson, j.a., cannat, m., millet, d.j. & elthon, d. (eds.): proceedings of the ocean drilling program, scientific results, vol. 153. ocean drilling program, college station, texas, 333–350. saccani, e. & tassinari, r. (2015): the role of morb and ssz magma-types in the formation of jurassic ultramafic cumulates in the mirdita ophiolites (albania) as deduced from chromian spinel and olivine chemistry.– ofioliti, 40, 37–56. saccani, e., dilek, y. & photiades, a. (2017): time-progressive mantle-melt evolution and magma production in a tethyan marginal sea: a case study of the albanide-hellenide ophiolites.– lithosphere. doi:10.1130/l602.1. saunders, a.d., tarney, j., marsh, n.g. & wood, d.a. (1980): ophiolites as ocean crust or marginal basin crust: a geochemical approach.– in: panayiotou, j. (ed.): ophiolites, proc. int. ophiolite conf. nicosia, cyprus, 193–204. schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., scheffer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpinecarpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss j. geosci., 101, 139–183. doi: 10.1007/s00015-008-1247-3 šegvić, b., lugović, b., slovenec, da. & meyer, h.-p. (2016): mineralogy, petrology and geochemistry of amphibolites from the kalnik mt. (sava unit, north croatia): implications for the evolution of north-westernmost part of the dinaricvardar branch of mesozoic tethys.– ofioliti, 41, 35–58. doi: 10.4454/ofioliti. v41i1.441. serri, g. & saitta, m. (1980): fractionation trends of gabbroic complexes from high-ti and low-ti ophiolites and from the crust of major oceanic basins: a comparison.– ofioliti, 5, 241–264. serri, s. (1981): the petrochemistry of ophiolitic gabbro-complexes: a key for classification of ophiolites to low-ti and high-ti types.– earth planet. sci. lett., 52, 203–212. shervais, j.w. (2001): birth, dead, and resurrection: the life cycle of supra-subduction zone ophiolites.– geochem. geophys. geosys. 2, 1010, 45 p. doi: 10.1029/2000gc000080. shiffman, p. & lofgren, g.e. (1982): dynamic crystallization studies on the grande ronde pillow basalts, central washington.– j. geol., 90, 49–78. doi: 10.1086/628651 šimunić, an., pikija, m., hećimović, i. & šimunić, al. (1981): osnovna geološka karta sfrj 1:100000. tumač za list varaždin l33-69 [basic geological map of sfry 1:100000, geology of the varaždin sheet – in croatian].– institut za geološka istraživanja zagreb, savezni geološki zavod beograd, 1–81. šimunić, an., pikija, m. & hećimović, i. (1982): osnovna geološka karta sfrj 1:100000, list varaždin l33-69 [basic geological map of sfry 1:100000. varaždin sheet – in croatian].– institut za geološka istraživanja zagreb, savezni geološki zavod beograd. slovenec, da. & lugović b. (2000): ultramafic cumulate rocks from the medvednica mts. ophiolite complex (northwestern croatia).– in: vlahović, i. & biondić, r. (eds.): proceedings of the 2nd croatian geological congress. institute of geology, zagreb, 379–385 (in croatian with english summary). g eologia c roatica slovenec and šegvić: the first record of ultramafic cumulates from the mt. kalnik ophiolite mélange in the sw part of the zagorje-mid-transdanubian ... 197 slovenec, da. & lugović, b. (2008): amphibole gabbroic rocks from the mt. medvednica ophiolite mélange (nw croatia): geochemistry and tectonic setting.– geol. carpathica, 59, 277–293. slovenec, da., lugović, b., meyer, h-p. & garapić-šiftar, g. (2011): a tectono-magmatic correlation of basaltic rocks from ophiolite mélanges at the north-eastern tip of the sava-vardar suture zone, northern croatia, constrained by geochemistry and petrology.– ofioliti, 36, 77–100. stampfli, g.m. & borel, g.d. (2002): a plate tectonic model for the paleozoic and mesozoic constrained by dynamic plate boundaries and restored synthetic ocean isochrons.– earth planet. sci. lett., 196, 17–33. stampfli, g.m. & borel, g.d. (2004): the transmed transects in space and time: constraints on the paleotectonic evolution of the mediterranean domain.– in: cavazza, w., roure, f., spakman, w., stampfli, g.m. & ziegler, p.a. (eds.): the transmed atlas: the mediterranean region from crust to mantle. heidelberg, germany: springer, 53–80. doi: 10.1007/978-3-642-18919-7_3 stevens, r.e. (1944): composition of some chromites of the 255. western hemisphere.– amer. mineralogist, 29, l–34. streckeisen, a.l. (1974): classification and nomenclature of plutonic rocks. recommendations of the iugs subcommission on the systematics of igneous rocks.– geol. rdsch., 63, 773–786. stormer, j.c. (1973): calcium zoning in olivine and its relationship to silica activity and pressure.– geochim. cosmochim. acta, 37, 1815–1821. doi: 10.1016/00167037(73)90144-0 sun, s.s. & mcdonough, w.f. (1989): chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes.– in: saunders, a.d. & norry, m.j. (eds.): magmatism in ocean basins.– geol. soc. london, spec. publ., 42, 313–345. doi: 10.1144/gsl.sp.1989.042.01.19 sun, s.s. & nesbitt, r.w. (1978): petrogenesis of archaean ultrabasic and basic volcanics: evidence from rare earth elements.– contrib. mineral. petrol., 65, 301–325. doi: 10.1007/bf00375516 tatsumi, y. & eggins, s. (1995): subduction zone magmatism.– cambridge, massachusetts, usa, blacwell, 221 p. taylor, s.r. & mclennan, s.m. (1985): the continental crust: its composition and evolution. blackwell, oxford, 312 p. tomljenović, b., csontos, l., márton, e. & márton, p. (2008): tectonic evolution of the northwestern internal dinarides as constrained by structures and rotation of medvednica mountains, north croatia.– geol. soc. london, spec. publ., 298, 145–167. doi: 10.1144/sp298.8 tribuzio, r., riccardi, m.p. & ottolini, l. (1995): trace element redistribution in high temperature deformed gabbros from east ligurian ophiolites (northern apennine, italy): constraints on the origin of syndeformation fluids.– j. metamorph. geol., 13, 367–377. doi: 10.1111/j.1525-1314.1995.tb00226.x tribuzio, r., tiepolo, m., vannucci, r. & bottazzi, p. (1999): trace element distribution within the olivine-bearing gabbros from the northern apennine ophiolites (italy): evidence for post-cumulus crystallization in mor-type gabbroic rocks.– contrib. mineral. petrol., 134, 123–133. doi: 10.1007/s004100050473 vrkljan, m. (1989): eruptive rocks from mt. kalnik.– phd thesis, university of zagreb, zagreb, 94 p. (in croatian with english summary). vrkljan, m. & garašić, v. (2004): different geochemical signatures developed in some basic magmatic rocks of mt. kalnik (north croatia).– rudarsko-geološkonaftni zbornik, 16, 65–73. wager, l.r., brown, g.m. & wadsworth w.j. (1960): types of igneous cumulate.– j. petrol., 1, 73–85. doi: 10.1093/petrology/1.1.73 wager, l.r. & brown, g.m. (1968): layered igneous rocks. oliver & boyd, edinburgh and london, 588 p. wakabayashi, j. & dilek, y. (2003): what constitutes “emplacement” of an ophiolite?: mechanisms relationship to subduction initiation and formation of metamorphic soles.– in: dilek, y. & robinson, p.t. (eds.): ophiolites in earth history.– geol. soc. london, spec. publ., 218, 427–447. wass, s.y. (1979): multiple origins of clinopyroxenes in alcalic basaltic rocks.– lithos, 12, 116–132. geologia croatica 45 87-93 3 fig. 2 pl. zagreb 1992 udc 551.763.31 (450) scientific paper open circulation facies in the cenomanian of the northeastern mar­ gin of the friuli platform: the !udrio valley case (ne italy) -dario sartori01, giorgio tunis2 and sandro venturinp key words: early-middle cenomanian, margin se­ quence, friuli platform, calcisphaerulidae, favusella, transgressive events the early·middle cenomanian margin sequence of val ludrio, connected with the northeastem margin of the friuli platform shows intercalated layers with pelagic organisms: calcisphaerulidae and plankton ic forams, among which is favwsella. these are interpreted as transgressive episodes recorded in a calbonate ramp sequence related to a tectonically subsiding margin. ln the dinaric and friuli plat· forms two distinct calcisphaerulidae and planktonic forams facies are distinguished for the cenomanian. the first one, of early-middle cenomanian age, which is also present in the ludrio sequence, de­ veloped in platform margin zones subjected to drawning. the sec­ ond one, of late cenomanian age, developed in more internal areas of the dinaric and friuli platforms, and can be related to the trans­ gression associated with the oae 2 event. l. introduction several margin sequences of the friuli platform, representing the north western extension of the dinaric platform (fig. l) during the latest albian and cenomanian, are characterized by pelagic influxes with planktonic organisms (cousin, 1981; ghetii, 1987; koch et al. , 1989; venturini & tunis, 1990). the sequence of the !udrio valley (fig. 2) consists of platform margin carbonates, the outcropping lower part of which is v alanginian, whereas the top is senonian. this paper takes into consideration the early-middle cenomanian limestones showing marked open facies as indicated by the presence of planktonic organisms, with the aim of explaining the significance of these facies. 2. the cenomanian of the iudrio valley the latest alb ian of the !udrio sequence marks a change of depositional pattern. in fact, latest albian facies, represented by bioclastic packstones and grainstones, can be referred to as a more open environment of deposition with respect to the underlying platform carbonates belmging to the cellina limestone unit the following early-middle cenomanian sequence consists of even more open facies, characterized by an increased energy of the system and very high organic productivity. the unit analyzed, about 250 m thick, outcropping in the southwestem sector of 1 agip s.p.a., 1-20097 s. d.onato milanese, milano the !udrio valley between albana and bodi goi, consists of a succession of bioclastic sands: alternating bioclastic packstones and grainstones and subordinate rudstones. mudstones seem to be lacking. most of the grains of these carbonate sands are frag­ ments of fossils (pl. l, l and 2 ; pl. il, l and 2) which are subjected to breakage, abrasion, and sometimes, round­ ing processes. fine to medium sized granular calcite ce­ ments fill intergranular porosity in packstones and grainstones. relict of marine phreatic cements can be also recognized. rare vadose crystal si lt possibly indicates the occurence of sporadic subaerial exposure episodes. many calcitic cemented fractures of tectonic origin are present. orbitolina (conicorbitolina) conica (d'archiac) (pl. l, 1,2,3,4) is the most common macroforaminifer observed in bioclastic sands from the bottom to the top of the studied sequence. some layexs contain praealveolina gr. cretacea (d'archiac) (pl. l, 4,5,6). other foraminifers such as trocholina sp., pseudorhapydionina sp., cuneo/ina pavonia d'orbigny, nezzazata simplex omara, nezzazatidae, miliolidae, ophthalminidae, textulariidae, valvulinidae, lituolidae, etc. have also been observed. macrofossils are represented by rudists (mostly radiolitidae and also caprinidae) and subordinate echi­ noids, corals, brachiopods, gastropods (among which are nerineids). however, most of these fossils have been broken into fragments and compose the bioclastic fraction of the carbonate sands. these facies developed in high energy ramp envi­ ronments in which bioclastic sediments were transported and accumulated by wave activity. these environments were also influenced by sea level fluctuations which led to sporadic subaerial exposures. wackestones and packstones with planktonic or­ ganisms, the most common of which are calcisphaerulidae (pl. ii, 1.2,3), alternate with the forementioned bioclastic packstones and grainstones. in these facies there are . also some planktonic foraminifers, among which are favuse/la washitensis (pl. il, 3, 5, 7), favusella sp. (pl. n. 4), hedberge/la sp. (pl. il, 6) and extremely rare rotalipora. the observed planktonic forms may also 1 istituto di geologia e paleontologia universit& degli studi di trieste, p. le europa t, 1-34127 trieste 3 agip-s.p.a .• v. c. menotti l, 1-48023 marina di ravenna, ravenna .,., ..,. .~ ~ u .:! cio' o g o = l. l 2 3 4 m~ d .. u---~-= : : : . -:-:-:.-: -. ---o l 2 3 km iuorio valley o 50 iookm ~ carbonatic ~platform ~basin [:).::::] seamount upper cretaceous fig. l ·location of the !udrio valley (left): l. mesozoic limestones, 2. maastrichtian flysch, 3. paleocene flysch, 4. lower eocene flysch. paleographic map of upper cretaceous of peri adriatic area (right), modified from cati et al (1987). the arrow shows the location of the examined area. sanorio, tunis & venturini : cenomanian open facies ... (/) :j o w u e: ..... w a: u a: w q. q. :j (/) :::> o w u e: ..... w a: u a: w ~ o ..j ~z o lli ..j(/) r--zq:uj ::>u z e: -z e: ~ o z w . u ~ ~ o ..j a: z w<l a.q.~ ::>e: 9z ~e: ~~ o a. ..j <l z <l ~ w a: o: e: m 0:: w ..... :::> e: i z <t ..j ~ 700 . ' '·l' , ~ ' , , ~ , , , .. , ~ ..... ~ 'l',', ....:: \ .. ',_l'" , .. , .... 't'''(" .... , , ' " , , ,, ' ~l .. ~ ', lo-o. ~ ~r-:: ,~ .. .0"1·-.''~ ' , . , ' , 600 ' , ' , ' , , ' , ' ••_!_' ,_ ' l, ' l ' , ' ' , , ' ~ ., ... ' .. ''"~l ' ' , , '"'''''' ... ''l··· ''.l'' "" .. .. ~~ -... ' ~ ' .. ,, ,,._lo.-500 ,.,.,',,1, ' l ... ... , ... 1--'• . , , ' , 1---' l .. \ .... , , , l" . , t-,,,,l l .... ,,,, ,', .. l ... .. ... ' , .. ( .. , l• ,,,,'1'''" .. ~ 400 ,,l , , , ,,,,, o .. ~9 "-~·<:) ... \ l, .. • 'l "' l , l· , . , ' ·_l' . ... .. .. -' 1·~.-o. ,_ '·l-:. ' ·.r-, .. .. , 300 ,, ,,,,,,, .. ,, l l 200 ''1''' ... l .... l l , ' t ;' l, l ',,., 100 .. , ... , ' , .. l ... ,, l l j -/,l 7" 'j , .. , , "' ' \ "' ' '/'l'',, , ' , \ ' ... \,,l ' , ' , l',\ mo .. l l ' , ... ' , 1°~/l~~: l 3 l markers keramos~haerina tergestina rotorbinella scarsellai no significant markers praeolveolino gr. cretoceo colcisphaerulidae, fovusello, rofolipora orbi totina conico proeolveolino gr. cretoceo fovusello, colcisphoerulidoe praealveolino gr. cretoceo colcisphoerulidoe fovusello, colcisphaerulidoe orbitolina cuvillieri neoiroqio insolito salpingorello dinorica polorbitolino lenticuloris 1\ bocinello /lithocodium j cyonobocterial mots no significant markers campanellula copuensis actinoporello podolico protopeneroplis trochonguloto 4 fi g. 2 • stratigraphic column of the cretaceous limestones outcropping in the l udrio valley. the arrow s show pelagic influxes. l. mudstone-wackestone, 2. packstone·grainstone, 3. intraformational breccias. 4. bacterial mats. 89 l 90 geologia croatica 45 nnw sse tolmin basin friuli platform adriatic platform l udrio ' latest cenomanian b earlymiddle cenomanian fig. 3 calcisphaerulidae facies in the cretac.epus sequence of northeastem edge of the friuli platform (!udrio valley). be scattered in the orbitolina bearing grainstones. as­ sociated with these planktonic organisms there are also benthic foraminifers typical of outer platform environ­ ment, such aslenticulina (pl. ii, 8, 9, 10) and gave/ine/la. these facies rich in calcisphaerulidae and plankton ic forams were deposited in more open and low energy environments probably during high sea level stands. the described sequence is overlain by bioclastic rudist limestones of possible late cenomanian age. 3. conclusion the studied sequence is very similar to the cenomanian section described by koch et al. (1989) outcropping in the area of trnovo, where there are the same facies bearing calcisphaerulidae and planktonic forams. these two sequences are the representatives of two sectors located along the same margin which were char­ acterized by the same sedimentary evolution. furthermore, sediments with favusella and calcisphaerulidae have been reported by šribar & plenlčar (1990) in the cenomanian of southwestern slovenia. identical facies to those of !udrio are present in the early-middle cenomanian sequence of mrežnica valley (fuček & glovacki-jernej, 1991), belonging to the northeastern margin of the dinaric platform. in analogy to the trnovo sequence, also in the cenomanian of l udrio there is a preci se depositional trend. the sequence mostly consists ofbioclastic facies lacking carbonate mud and deposited in high energy environment, with intercalated layers characterized by the presence of mud and planktonic foraminifers. in many zones of the friuli platform (cati et al., 1987) and in some areas of the apennine platforms (accord i et al., 1987), starting from the cenomanian or from the_ very late albian, bioclast­ dominated facies replace the inner platform faci es of early cretaceous. these facies almost always deposited on highly sub­ siding platform margins, often subjected to drowning. in fact, the following senonian and cenozoic facies o fl udrio record the subsequent drowning of the examined margin. cenomanian facies of the l udrio valley are charac­ terized by high sedimentation rates and bioclastic carbonates production. this possibly reflects the global increase of sea level rise occured throughout the cenomanian. calcisphaerulidae and planktonic foraminifers layers intercalated with the bioclastic facies of the i udrio valley mark transgressive episodes recorded in a carbonate ramp sequence related to the tectonically subsiding margin of the friuli platform. the presence of favusel/a is indicative of an envi­ ronment of deposition that was not very deep (koutsoukos et al ., 1989), sometimes subjected to subaerial exposure periods, as documented by vadose plate i l. grainstone with orbitolina (conicorbitolina) conica (d'archiac), aj 89, x 15 2. orbitolina (conicorbitolina) conica (d'archiac), aj 94 x 40 3. orbitolina (conicorbitolina) conica (d'archiac), gl 134, x 45 4. praea/veolina gr. cretd.:ea (d'archiac)·, and embryonic apparatus of orbitolina (conicorbitolina) conica (d'archiac), tj 16 x 30 5. praea/veolina gr. cretacea (d'archiac), aj 115, x 40 6. praealveolina gr. cretacea (d'archiac), tj 16, x 45 92 cements observed in some levels. in the dinaric and friuli platforms, two different transgressive facies, with calcisphaerulidae and planktonic foraminifers characterize the cenomanian sediments. the first one (early-middle cenomanian) is associated with the orbitolina (c.) conica bioclastic sands and is typical of platform margins sub­ jected to drowning (fig. 3a). this facies, which is present in the l udrio sequence, is charactmzed by calcisphaerulidae and f avusel/a. the second facies, ascribed to the cenomanian-turonian boundary, and more precisely to the latest cenomanian, if correlated with coeval faci es of the a penn ines (p arisi et al., 1989) and of south-east france (grosheny & 1ronchetti, 1991) is characterized by calcisphaerulidae and whiteinella (gušić & jelaska, 1990). this fa­ cies, almost always associated with anoxic or euxinic environments, is recorded in more internal areas of the platform (fig. 3b), and, as put to evidence by jenkyns (1991), can be ascribed to transgression associated with the oae 2 event. acknowledgement financial support from m.u.r.s.t. 60% "evoluzione dei bacini sedimentari terziari" (resp. g . catani) is gratefully acknowledged. 4. references accordi, g., carbone, f. & sirna, g. (1987): sedimentary events and rudist assemblages of maiella mt. (central italy): paleobiogeographic implications. geol. romana, 26, 135-147, roma. cati, a., sartorio, d. & venturini, s. (1987): carbonate platforms in the subsurfuce of the northern adriatic area.mem. soc. geol. lt, 40,295-308, roma. cousin, m. (1981): les rapport alpes-dinarides. les confins de l' ital i e et de la yugoslavie. -soc. g eo l. du nord, l , 1-521; ii, 1-521, villaneuve d'ascq. fucek, l. & glovacki-jernej, ž. (1991): the reflection of the global cenomanian(furonian transgression; the examples from brač island, dugi otok island and the mrežnica region.-abstr. of sec. int. symp. on the adriatic carb. plat., 101, zadar. ghetti, s. (1987): evoluzione cretacica del margine occidentale della piattaforma friulana.-tesi di douorato sc. della terra, 1-205, firenze. geologia croatica 45 grosheny, d. & tronchetti, g. (1991): les as­ sociations de foraminiferes du passage cenomanien turonien a vergons. in: crumiere, j.p., cotillon, p. & schaaf, a. (eds.): les evenement de la limite cenomanien turonien. -excursion post-colloque dans le sud-est de la france. livret-guide, 70-75, grenoble. gušić, i. & jelaska, v. (1990): upper cretaceous stratigraphy of the island of brač within the gea­ dynamic evolution of the adriatic carbonate plat­ form.-djela jugosl. akad. znanosti i umjetnosti, 69, 1-160, zagreb. jenkyns, h. (1991): impact of cretaceous sea level rise and anoxic events on the carbonate plat­ form of yugoslavia.-am. ass. petr. geol. bull., 75 (6), 1007-1017, tulsa. koch, r., ogorelec, b. & orehek, s. (1989) : microfacies and diagenesis of lower and middle cretaceous carbonate ltocks ofnw-yugoslavia. (slovenia, trnovo area).-facies, 21, 135-170, erlangen. koutsoukos, e.a.m., leary, p.n. & hart, m. b. (1989):favusella michael (1972): evidence of ecophenotypic adaption of a planktonic foraminifer to shallow-water carbonate environments during the mid-cretaceous. journal of foraminiferal research, 19 (4), 324-336, washington. parisi, g., coccioni, r., battistini, f., pier­ giovanni, f. & rossi,r. (1989): the "livello bonarelli" the marker bed one of the mid-cretaceous worldwidc anoxic events .-in : coccioni,r., monechi, s. & parisi,g. (eds): abstracts of the igcp project 262, working group 2 "pelagic facies". univ. urbino, 126-133, urbino. šribar, l. & plenicar, m. (1990): upper cretaceous assemblage zones in southwestern slove nia. -geologija, 33, 171-205, ljubljana. venturini, s. & tunis, g. (1989): nuovi dati ed interpretazioni sulla tettonica del settore meri­ dionale delle prealpi giulie e della regione al conflne tra italia e iugoslavia.gortania,io, 5-34. manuscript received march, 31.1992. revised manuscript accepted may, 18.1992. plate ii l. wackestone with calcisphaerulidea, tj 28, x 50 2. calcisphaerulidea, gl 141, x 120 3. favusella washitensis (carsey) and calcisphaerulidea, gl 141, x 100 4 favusella sp., gl 136 x 90 5. favusella washitensis (carsey), gl 139 x 90 6. hedbergella sp., gl 139 x 70 7. favuse/la washitensis (carsey) gl 139 x 70 8. lenticulina sp. and orbitolina sp, 136 x 50 9. lenticulina sp. , tj 28, x 50 lolenticulina sp. , gl 139, x 70 sartorio, tunis & venturini : cenomanian open facies ... plate ii 93 ab stra ct the south-western part of croatia, i.e. the area of central istria, comprises the research area, (approximately 500 km2). it is characterized by a fl ysch complex with a great number of isolated relief landforms, termed badlands. the im­ portance of badlands (areas with sparse or no vegetation) lies in the fact that sediment production from these areas is 8000 times higher than from areas with vegetation. here, the badland inventory presents 5568 distinguishable bad­ lands (polygons) with a total badland area of 10.7 km2. spatial analysis of the badland inventory showed that erosive channel fl ow at the steep slope foot is the most important factor in badland formation and development for the area of central istria. keywords: badland, inventory, spatial analysis, fl ysch complex, central istria  geologia croatica 67/1 1–15 17 figs. zagreb 2014 geologia croaticageologia croatica the analysis of the � ysch badlands inventory in central istria, croatia  vlatko gulam*, davor pollak* and lászló podolszki* * department of hydrogeology and engineering geology, croatian geological survey, sachsova 2, 10000 zagreb, croatia; (vlatko.gulam@hgi­cgs.hr, davor.pollak@hgi­cgs.hr, laszlo.podolszki@hgi­cgs.hr) doi: 10.4154/gc.2014.01 1. introduction the long period of time necessary for the majority of the earth’s relief formation presents a problem in measuring the processes which occur during that period (howard & kerby, 1983). on a smaller scale (in area and time), the badlands as landforms can be used as case studies for research and understanding the bigger systems (wainwright & brazier, 2011) because all the exogenetic processes: weathering, denudation and depo­ sition occur and interweave there. changes which occur on bad land relief are dynamic, and can be measured because they happen in a relatively short time span. badlands are also very common worldwide (mediterranean environment: tunisia, de ploey, 1974; morocco, imeson et al., 1982.; wain­ wright & thornes, 2003., drylands in africa: board­ man et al., 2003.; eriksson, et al., 2003.; feoli et al., 2002.; achten et al., 2008; chile: maerker et al., 2008; india: joshi et al., 2009; china: liu et al., 1985). these are the main reasons for the large number of scientifi c papers in which badland detection, description and measurements of dif ferent processes are presented. the term badland originates from the early french colo­ nists in northern america who encountered terrain that was bad, or diffi cult to cross (wainwright & brazier, 2011). there are many defi nitions of badlands in the litera­ ture but they all refer to the relief with or without sparse vegetation cover, steep slope inclination, a dense hydrographic network, with or without a thin regolith, and the materials are usually unconsolidated or weakly consolidated clay rich bedrock. marls and recent alluvium in particular can erode rapidly and they have a great denudation value. there are also some scientifi c papers in which the denudation values are smaller because some badlands or at least some parts of badlands can be stable for thousands of years (wise et al., 1982; wainwright, 1994; howard, 1997; díaz­ hernández & juliá, 2006). badlands can also be de­ fi ned as areas where intensive piping, erosion and mass wast­ ing processes combine with fl uvial processes to produce a rugged, hummocky, dissected and strongly gullied topogra­ phy (bryan & yair, 1982). a large number of factors and processes have an infl u­ ence on badland formation and maintaining it as a complex relief form. the analysis and research of badlands can be undertaken at a variety of different scales. although nume­ rous factors and processes infl uence badland development, most areas in which natural badland development is extensive share certain lithological and climatic characteristics (bryan & yair, 1982). also in badland defi nitions sparse or no vegetation at all is one of the most important factors for the persistence of badlands and not the cause of badland formation. in recent times the anthropogenic infl uence is im­ portant in badland development, as in many locations the vegetation cover is disappearing due to human activity. geologia croatica 67/1geologia croatica 2 badlands in central istria are isolated relief units (in the terms of area they are smaller than 1 km2), not like the globally known type and investigated localities (which can stretch over more than a dozen square kilometres): dinosaur provincial park, alberta, canada (bryan et al. 1987) or the henry mountains, utah, sad (gilbert, 1880; howard, 1994). the small areas of badlands in central istria (the biggest badland has an area of 0.08 km2) suggest that an unstable chain of exogenetic processes exist in that area which dictates badland formation, development and persistence in conditions (lithological, geomorphological and climatic ones) which are characteristic for the central istrian area. these are detailed in this paper. in the majority of the literature which refers to the investigation of erosion in the area of central istria, it is stressed that the aforementioned area is characterized by very intensive exogenetic processes (jurak et al., 2002; petraš et al., 2008; zorn, 2009a, 2009b). here, the badlands are marked as locations with excessive erosion (jurak & fabić, 2000), with sediment production up to 8000 times higher than in locations which have some kind of vegetation cover. high se­ diment production from bare flysch in combination with intensive surface flows (flysch is characterized by low infiltration values and rapid runoff formation) are very common causes of backfilling of artificial accumulations, retention dams and drainage canals in traffic infrastructure. the goal of this work is to present the badland inventory and results of spatial analysis which can help in understanding the conditions necessary for badland formation and development in the flysch area of central istria. 2. basic charateristics of the istrian peninsula geographical, geological and morphological characteristics of the istrian peninsula differ from the rest of croatia. this is the main reason why the istrian peninsula is usually regarded as a separate unit (vresk, 1987; vlahović et al., 2003.) in the scientific literature, and also why istria is treated as a separate administrative unit. 2.1. geographical characteristics of the istrian peninsula the administrative unit of istria is located in the southwestern part of croatia (fig. 1) with an area of 2820 km2. the climate of the istrian peninsula is also variable, particularly in big differences in arithmetic mean of annual va­ lues of precipitation. in the south-west and west these vary from 800–900 mm/year, in the middle part from 1200–1300 mm/year and in the north­east (mountainous area) from 2000–2500 mm/year (gajić­čapka et al., 2003). similar differences can also be noticed in the arithmetic mean of annual values of temperature: from 14°c in the south­west to 6°c in the north­east (zaninović et al., 2004). so, there are three types of climate on the istrian peninsula (ogrin, 2005): two types of submediterranean climate and a mediterranean one. according to köppen, these types are: cfb (in the central part), cfa (in the eastern and western coastal part) and cs (in southern coastal part). the istrian peninsula is mainly covered by forest (61.1 %). agricultural land 35.4 %, urban and artificial areas 3.3 % and water surfaces account for around 0.2 % of the land surface (azo, 2006). 2.2. geological characteristics of the istrian peninsula postsedimentation tertiary tectonics has influenced the complex structure of deposits of the adriatic carbonate platform, but the istrian peninsula is one of the „stratigraphic oases” where it is possible to study all major events from geological history (velić et al., 2003). from the geological aspect, the istrian peninsula can be divided into three major regions (which also correspond to the division into historical regions according to the local population): 1) red istria – jurassic­cretaceous­eocene plains (south­ ern and western part of the peninsula): the term originates from the thick quaternary deposits of terra rossa which overlie carbonate bedrock of mesozoic and tertiary age; 2) white istria – cretaceous­eocene carbonate platform and clastic zone (mainly the massifs of ćićarija and učka) with characteristically imbricated structure: the term originates from the white colour of cretaceous and eocene weathered limestones; 3) grey istria – eocene flysch basin (central istria): the term originates from the grey colour of the marls which are interbedded with sandstones which toge­ ther form the flysch complex. tectonic units of the istrian peninsula can generally be divided in the laramian tectonic unit (numbered 1 in fig. 2) and postlaramian tectonic units (2­5 in fig. 2; polšak & šikić, 1973). here, the most important unit is unit 3 (pazin synclinorium) and part of unit 4 (trieste synclinorium). the pazin synclinorium represents the tectonic unit formed from the eocene to the oligocene, during which time flysch sedimentation occurred in central istria (bergant et al., 2003). figure 1: research area in the central part of the istrian peninsula (marked by brown). gulam et al.: the analysis of the flysch badlands inventory in central istria, croatia geologia croatica 3 2.3. geological characteristics of the research area the research area includes almost the entire flysch complex on the istrian peninsula. only tectonic unit 5 is not included in the research area (the imbricated and overthrusted structure of the ćićarija, učka and labin basin), although it contains flysch deposits (fig. 2). the reason for the exclusion of this unit lies within the goal of this research: determination of the conditions necessary for badland formation and development (ie. which of the exogenetic processes is important). in unit 5, the tectonic movements are one of the main factors in relief formation and those movements are hard to measure and quantify (they appear in geological time), so unit 5 was not taken into consideration. the research area is in the central part of the istrian peninsula (approximately 487 km2, fig. 1). the research area mainly consists of deposits of globigerina marl and flysch which have low durability and high ero­ dibility, confirmed by jurak et al. (2002), petraš et al. (2008) and gulam (2012), and predetermined by the lithological, mineralogical, physical and mechanical properties of these materials. these properties of the globigerina marl and flysch develop under a special set of conditions. the stratigraphic setting of the marl and flysch deposits of middle istria is shown on a simplified geologic column in fig. 3, from which it can also be seen that the base of the flysch complex and globigerina sediments is composed of foraminiferal limestones with thin transitional sediments (marls with crabs). the term globigerina marl originates from the planktonic foraminifera globigerina and contains different ratios of carbonate and siliciclastic components. the carbonate component is mainly cryptoto microcrystalline calcite, while the siliciclastic components are mainly quartz and clay which originated from the mainland (bergant et al., 2003). globigerina marls are deposited in a deep sea environment as confirmed by their constituent microfauna (juračić, 1980). flysch of the central istria is superpositioned on the globigerina marl and can be divided into the upper and lower parts (bergant et al., 2003), with the complex thickness of about 90­100 m (fig. 3). the lower part of the flysch complex is composed of a rhythmical exchange of marl and carbonate sediments varying in thickness from 0.3 up to 7 m. carbonate deposits can be conglomerates, foraminiferal breccia, arenites and siltstones. within the lower part of the flysch complex, carbonate megalayers of various thicknesses are very common (up to couple of metres, bergant et al., 2003). in the upper part of the flysch complex there are deposits of carbonate-siliciclastic turbidite sediments which are thinly bedded and represent only the upper part of the bouma turbidite sequence (tb­e, tc­e and td­e, bergant et al., 2003), so called the undercut turbidite sequence (bergant et al., 2003). 3. results 3.1. relief dissection the relief dissection map generally indicates the areas of higher relief energy which equates to areas of potential higher figure 2: tectonic units of the istrian peninsula (according to polšak & šikić, 1973); 1. west istrian jurassic cretaceous anticline; 2. savudrija buzet anticline; 3. pazin synclinorium; 4. trst synclinorium; 5. imbricated and overthrusted structure of ćićarija, učka and labin basin; a – autochton; b transitiona structures; c – paraautochton. figure 3: a simplified geological column of kotli in central istria (accor ding to bergant et al., 2003). geologia croatica 67/1geologia croatica 4 values of denudation and vice versa (marković, 1983). for some areas the value of relief dissection is determined by lithology, type and thickness of the engineering soil, tectonic activity and the type of dominant exogenetic processes. the relief dissection map of istria was generated using a topographic map at 1:25.000 scale. categorization of the relief dissection was carried out according to gams et al. (1985) and is shown in fig. 4. it can be concluded that the map of the relief dissection (fig. 4) also corresponds to the potential zones of exogenetic processes intensity. the south­ western part of the istrian peninsula is mainly characterized by plains of low dissection (6.6 %) and the relief of low dissection (46.9 %). these attributes are predefined by: low erodible carbonate rocks of jurassic and cretaceous age and the „modest” tectonic activity in that area. the central part of istria, where the flysch complex deposits lie, is characterized by the relief of moderate dissection (100­300 m). although the tectonic activity is not emphasized in this area, the relief of moderate dissection is the consequence of high erodibility and low durability of these flysch sediments. because of these properties the central part of istria is characterized by intense exogenetic processes. all the canyons on the istrian peninsula (mirna, lim, raša) and the mountain massive of ćićarija occur in this category (moderate dissection). the mountain massif of učka, in the eastern part of istria is composed mainly of carbonates of cretaceous age and they are in the category of relief of extensive dissection (2.8 %) which reflects the effects of tectonics. 3.2. badlands inventory worldwide, there are many methods for the detection and for sorting out the areas with excessive erosion, but gene­ rally they can be divided into two main groups: • field mapping and • remote sensing. figure 4: map of the relief dissection of istria. figure 5: badland inventory of central istria; 1. badland boundary, 2. watershed boundary, 3. studied area boundary. gulam et al.: the analysis of the flysch badlands inventory in central istria, croatia geologia croatica 5 the research area (fig. 1) is almost 500 km2 with a relatively high percentage of badlands. for example, according to jurak & fabić (2000) badlands in the catchment of the krbunski stream constitute 6 % of the catchment area. field mapping was impractical and expensive for the research area due to terrain configuration and the large area of interest. therefore the logical, practical and adequate method for producing a badlands inventory in the research area, is the usage of remote sensing. the method used in this research, consisted of reviewing the orthophoto maps at 1:5.000 scale (digital orthophotos of croatia) and marking every single badland with the unique id and contour of badland border on the terrain surface on these photos. the badland inventory of the middle part of istria was used for: 1) determining the ratio of badlands in the research area, 2) determining the spatial distribution of badlands and determining the areas with the maximal and minimal ratios of badlands and 3) spatial analysis in order to determine the most important conditions/factors necessary for badland formation and development in the flysch area of central istria. the badland inventory (data base) contains: (i) unique id of each badland, (ii) contour of badland border on the terrain surface (polygon) and (iii) total area of each badland. in the research area, 5568 badlands were singled out, with the sum of the total areas of badlands of 10.7 km2, which is 2.2 % of the research area. the research area with contour of badland border on the terrain surface (polygons) is shown in fig. 5. also the larger detail with the orthophoto as the background is given in fig. 5. on that orthophoto the badlands are easily recognizable. in the upper left corner of fig. 5 the detail of the database (from the badland inventory) is shown. 4. discussion 4.1. chain of exogenetic processes at the badlands the combination of exogenetic processes which takes place in the badlands needs to be explained to clarify the conditions under which badlands develop. two very important factors for badland development in the central part of istria are (gulam, 2012): 1) low durability sediments – badlands develop on the terrains where the bedrock is characterized by a very high susceptibility to periodic cycles of drying and wetting. as a result strong physical weathering occurs and the bedrock is covered with a thin, highly erodible, eluvium (10­20 cm). 2) erosive stream – badlands in the central part of istria are attached to gullies and valleys with very erosive periodic channel flow. badland development in central istria in terms of the geological time scale is explained on the theoretical and simplified model of a flysch terrain shown in fig. 6. most of the flysch terrain is covered by regolith which is the consequence of chemical and physical weathering and very low bedrock durability (fig. 6a). periodic concentrated channel flows erode the regolith overlying the flysch sediments, since its erosivity easily surpasses the erodibility of the regolith (fig. 6b). this process leads to gully incision (fig. 6c). the formation of gullies redirects sheet surface waters into channel flow causing an increase in the flow rate of waters running through them. deepening of the gullies is facilitated by this increase in water quantity, and the flanks steepen until eventually the regolith layer is detached and fresh rock is exposed – which is considered here as a badland (fig. 6d). further processes which determine badland „life” are cyclical and interdependent. the main phases of this chain of exogenic processes can be schematically represented as shown in fig. 6, (i­iv) and below: i fresh rock. low durability intact rock material very prone to physical weathering is one of the basic prerequisites for badland formation. ii weathering. in reality, fresh rock is rarely exposed at the very surface. on the steep badland slopes, fresh rock is not protected by a thick regolith layer and is exposed to physical weathering. perpetual cyclical processes of drying and wetting of fresh rock material easily and rapidly degrades the mechanical cha­ racteristics of bedrock and form a thin layer of highly erodible material – eluvium. iii denudation deposition. it is important to differentiate the processes by which eluvium is transported into the bottom of the gullies (fig. 6, iii). these pro­ cesses interact with slope inclination: • denudation 1) sheet erosion – occurs if the slope inclination is less than the angle of internal friction of eluvium (usually less than 35°). 2) mass movements (usually rockfalls) – result when the slope inclination is higher than the angle of internal friction of eluvium (usually more than 45°). 3) a combination of sheet erosion and mass movements – occurs if the slope inclination is near the value of the angle of internal friction of eluvium (usually between 35° and 45°). • deposition. iv erosion. talus sediment accumulated in the central part of the gully is eroded by periodic channel flow. the relationships between the four aforementioned main phases of badland evolution over time will determine whether badlands will develop (fig. 6e) or die out (fig. 6f). in conditions favourable for badland progress, the deepening of the gullies takes place until the periodic channel flow reaches the erosion base. at this point, the rockwall retreat (curry & chris, 2004; seong et al., 2009; zorn, 2012) of the gullies takes place. the magnitude of badland rockwall retreat is also guided by relationships between the major processes (i to iv) described earlier. if badland slopes are in close contact with periodic channel flow, erosion will take place. but if the position of the periodic channel flow does not change over time, rockwall retreat will diminish geologia croatica 67/1geologia croatica 6 figure 6: badland development and the chain of exogenetic processes. gulam et al.: the analysis of the flysch badlands inventory in central istria, croatia geologia croatica 7 leading to badland extinction. the same will happen if the water energy drops. the cyclical process is mainly continuous and has three constants – the same intact rock material with the same weathering potential, and the same mechanical properties of the resulting eluvium. according to these parameters, the denudation rate should be constant, but it also depends on the only variable in this cycle – climate. climate change or climate extremes dictate both very important and periodic factors in this cycle: wetting and drying periods, and erosion of the talus sediment by periodic channel flow. it should also be noted that the equilibrium cycle can also be disturbed by a change of erosion base level (for example by endogenic movements – geological time) or by anthropogenic activity (for example in civil engineering by changing the position of the periodic channel flows caused by road buildings – engineering time). explanations given for fig. 6, suggest the conclusion that the last link in the chain of exogenetic processes is the weakest – erosion by periodic channel flow (fig. 6, iv). in middle istria there is a periodic (or constant) channel flow of high erosivity in almost every stream order, but it is not necessary that the channel flow is in close contact with the steep flanks of valley or sediment accumulation (formed by sheet erosion or mass movements). it is clear from the discussion that the contact is necessary for the badland formation, development and reactivation, i.e. the contact is necessary for erosion and redeposition of the accumulated mate rials at the slope foot. the next logical question is: which factors cause formation of this close contact? the answer is given by spatial analysis described below. 4.2. the importance of bedding inclination on badland development big badlands in central istria (for example badlands in the vicinity of st. donat or boljun, fig. 5 and fig. 8) are characterized by bedding inclination between 5° and 20°. bedding steeper than 5° influences the forming of channel flows at the badland foot, shown in theoretical model in fig. 7. the model presents the terrain with constant channel flow in a gully where bottom is being eroded with equal rate (fig. 7a, f). by gully deepening (in bedrock) badlands are being formed on the flanks of the gully (rockwall) and the chain of exogenetic processes commences (fig. 6). when the channel flow reaches resistant, none or low erodible components of the flysch deposits (for example calcarenite sediments, fig. 7b, g), widening of the gully takes place (rockwall retreat). if the bedding is horizontal (e.g in the south ­eastern part of the ričica catchment) the rockwall retreat of the gully is equal on both flanks. if the bedding is inclined (for example badlands in vicinity of st. donat and boljun) the rockwall retreat of the gully takes place in one direction – in the direction of bedding inclination. in figs. 7c and 7h continuation of rockwall retreat is shown, while in fig. 7c the retreat is slowing as the flow widens (a larger area of flow means lower energy of flow i.e. lower erosivity). in fig. 7h the retreat value remains the same (as the flow energy remains the same). in fig. 7e the end stage is presented – gully without rockwall retreat with wide flow with very low value of erosivity (or none). in fig. 7j, on the other hand, a gully with the same level of activity is shown. on the far side (opposite side) of the flow, sediment accumulation takes place and eventually that side of the gully/valley will become inactive. the rockwall retreat continues (on the active side) until the appearance of some hindering factors stop it. hindering factors can be: bedding inclination change to a smaller value, a greater sediment production value than flow erosivity, as a result of a larger badland area, etc. initial bedding inclination has a great influence on badland formation and development, i.e. on the flow concentration at the slope foot. the results of spatial analysis of slope figure 7: rockwall retreat influenced by bedding inclination. geologia croatica 67/1geologia croatica 8 aspects (in badland and non-badland areas) in the south-eastern part of the ričica catchment and in the vicinity of st. donat and boljun (fig. 8) provide confirmation of this. 4.2.1. st. donat badland catchment st. donat badland catchment is approximately 2.7 km south of buzet in the centre of grey istria (fig. 8). the term originates from the village of st. donat, which is west of the badlands. st. donat badland catchment area on which the analysis was undertaken is 0.46 km2. the badland area in the catchment is 0.05 km2, which is approximately 9.2 % of the catchment area. the main flow is the kameršiač stream (its spreading is 112­292°). according to the basic geological map (1:100.000 scale), (pleničar et al., 1969), the catchment consists of a flysch complex (intervals of marls and sandstones with centimetre thick beds) of middle eocene age (3e2). the average bedding values in the catchment is 179/13°. the diagram in fig. 9 clearly shows that the maximum development of the badlands aspects is almost directly opposite to the bedding azimuth in the analyzed catchment (in correspondence with discussion associated with fig. 7), while the actual situation on the analyzed catchment is similar to that presented in fig. 7j. the areas with vegetation approximately correspond to the bedding surfaces (fig. 10), i.e. the maximum aspects of the areas with vegetation (fig. 9) are in the same direction as the bedding azimuth. the areas of blue and grey polygons in fig. 9 are almost symmetrically divided by the arrow which represents the value of azimuth for the kameršiač stream. this type of „butterfly” distribution (in which the values of aspect for badland and non-badland areas of the catchment are shown), is very common for the catchment areas of central istria when the whole catchment is characterized by uniform bedding values. this conclusion is also confirmed by the example of the boljun badland catchment analysis which is in the south­eastern part of flysch basin in boljunščica catchment (fig. 8). 4.2.2. boljun badland catchment the boljun badland catchment is in the north­western part of boljunšćica catchment area (fig. 8). the name ori­ ginates from the village of boljun which is south­east of the badlands. boljun badland catchment area on which the analysis was undertaken is 1.33 km2. the badlands in the catchment cover 0.16 km2, which is approximately 12.0 % of the catchment area. the main flow is the western confluent of the boljunšćica stream with an approximate north – south direction of flow. according to the basic geological map (1:100.000 scale) (šikić et al., 1969) the catchment consists of flysch complex (intervals of marls and sandstones) of middle and upper eocene age (e2,3). average bedding value on catchment is 262/8°. figure 8: spatial distribution of the analyzed locations; 1. horizontal bedding, 2. inclined bedding. gulam et al.: the analysis of the flysch badlands inventory in central istria, croatia geologia croatica 9 the „butterfly” distribution in fig. 11 is very similar to fig. 9. the maximum of the badlands aspect is opposite to the bedding azimuth and to the maximum aspect of slo­ pes with vegetation (non­badland area). this also confirms the discussion concerning fig. 7, i.e. confirms the fact that badlands on the catchments with uniform bedding are developing on the flanks which are opposite to the bedding azimuth. boljun badland catchment in 3d is shown in fig. 12 and it clearly shows that non-badland areas correspond approximately to bedding planes and that most of those areas are on the left side of the main flow in the catchment. these slopes are characterized by lower slope inclination and a higher area of spreading. 4.2.3. south-eastern part of the ričica catchment area the ričica catchment area is part of the southern part of the botonega catchment (fig. 8) with an area of 1.75 km2. the badland area in the catchment is 0.13 km2, which is approximately 7.4 % of the catchment area. the main flow is the ričica stream (spreading is 130­310°). the ričica catchment is in the central part of the flysch synclinorium and it is characterized by horizontal bedding. this is also the reason for the somewhat different badland aspect distribution in relation to the non-badland area, shown in fig. 13 by the blue arrow (presenting the flow of the highest order in that catchment area) as a division of the grey polygon into two parts, almost equal in area. this means that badlands form equally on each slope which is confirmed by the high overlapping of non­badland area (areas with vegetation, blue polygon) and badland area (grey polygon). the south­eastern part of the ričica catchment in 3d is shown in fig. 14. it is clearly visible that badlands develop and form on both flanks of the main valleys. the terrain is figure 9: analysis of slope aspect and badlands and their connection with the average value of bedding in st. donat badland catchment. figure 10: st. donat badland catchment in 3d; 1. watershed boundary, 2. badland boundary, 3. main stream geologia croatica 67/1geologia croatica 10 figure 12: boljun badland catchment in 3d; 1. watershed boundary, 2. badland boundary, 3. main stream figure 11: analysis of slope aspect and badlands and their connection with the average value of bedding in the boljun badland catchment. similar to that presented in fig. 7a–7e, i.e. the horizontal bedding predefines approximately equal development of badlands on each slope of each valley. 4.3. the influence of the valley cross section morphology on badland development after the badland inventory was prepared and visually analyzed, some general conclusions were reached: there is regu­ larity in the ratio of badlands in some smaller catchments to periodic channel flows (also for some larger constant flows). the ratio of badlands in some areas is increasing as the distance from the mouth of the river is growing, i.e. as the erosion base is becoming more distant. this conclusion is confirmed by simple spatial analysis in which the connection between the badland ratios on some parts of the analyzed catchment (segment) and the distance of the centroid of that part of the analyzed catchment (segment) from the mouth of the catchment is observed. these segments are formed by the principle of concentric clips where the centre is the mouth of the catchment. the spatial analysis for the botonega catchment is shown below (fig. 15). 4.4. botonega catchment area the botonega catchment represents the left tributary of the mirna river and has an area of 104.6 km2 with the height difference of 485 m. the highest elevation in the catchment area is 500 m while the lowest is 15 m above sea level. the catchment is fan shaped with botonega as the main flow and also as the flow of the highest order (6th order defined by the contour lines at 1:25.000 scale according to the methodo logy suggested by strahler, 1957). the badland area in the catchment is 2.0 %. the central valley (the botonega river valley) corresponds with the axis of the flysch basin which is bath shaped gulam et al.: the analysis of the flysch badlands inventory in central istria, croatia geologia croatica 11 figure 13: analysis of slope aspect and badlands and their connection with the average value of bedding in the south-eastern part of the ričica catchment. figure 14: south-eastern part of the ričica catchment badlands in 3d presentation; 1. watershed boundary, 2. badland boundary, 3. main stream ment and the badland ratio of each segment. this correlation confirms the visual analysis and it can be described with a linear function (with a very high factor of determination – 0.85). graduation of the red colour (fig. 15) shows this line ar distribution, i.e. light red marks the segments with low badland ratios and vice versa (dark red marks the segments with high badland ratios). to clarify, the very high value of the factor of determination means it is necessary to take into consideration the described chain of exogenetic processes (fig. 6). the flow concentration at the steep slopes foot, as one of the most important links in the chain, can be predefined by the shape of the valley cross section. if the cross section is u shaped there is a very high probability that the channel flow in the centre of the valley will not be in close contact with flanks (rockwall). the situation is reversed if the cross section is v shaped, then there is a very high probability that the cannel flow is in a close contact with the steep flanks of the valley (rockwall). if the valley cross sections for each segment on the branch of the hydrographic network marked with thicker blue line (fig. 15) are analyzed there will be 12 profile positions and 12 values. this branch is approximately in the centre of the botonega catchment area and it stretches from the river mouth to the final segment. the cross sections for each profile position were made and analyzed (fig. 17a & 17b) and four characteristic cross sections are also shown in fig. 15. on the cross sections, the vertical scale is enlarged by x 20 to emphasise the shape of the cross section. and stretches from the north­west to south­east. according to the basic geological map (1:100.000 scale, (sheets: trieste, ple ni čar et al., 1969; ilirska bistrica, šikić et al., 1972; ro vinj, polšak & šikić, 1969; labin, šikić et al., 1969)), flysch deposits cover approximately 86 % of the catchment area and the rest is alluvium (11 %) and carbonate deposits (3 %). spatial analysis for the area of the botonega catchment were undertaken as described in section 4.3 (fig. 15). segments are defined at 1 km intervals. fig. 16 shows the correlation between the distance of the centroid of each segment from the mouth of the catchgeologia croatica 67/1geologia croatica 12 figure 15: spatial analysis for the area of the botonega catchment with 1 km segments and characteristic valley cross sections. figure 16: correlation between the distance of each segment centroid from the mouth of the catchment and the badland ratio on each segment. the total height of each cross section is 10 m. in these cases the values which can determine the cross section shape are their width and area. the width is expressed in km and represents the distance between the two highest points of each cross section. the area of exaggerated cross section is expressed in km2 and it is defined by a horizontal line which connects the two highest points of the cross section and the profile line, (the area defined in this way is shown on four examples of exaggerated cross sections by a green colour in fig. 15). from the values shown in fig. 17, it is clearly visible that the badland ratio in the segments is reducing as the width and the area of cross section increases. both correlations result in very high factors of determination, approximately 0.76. the logical conclusion is that the cross section shape of the valley is very important in badland formation gulam et al.: the analysis of the flysch badlands inventory in central istria, croatia geologia croatica 13 and development as it is in direct connection with the channel flow concentration at the foot of steep valley flanks (rockwall). 5. conclusion the area of central istria is characterized by low tectonic activity but the relief dissection is moderate i.e. relief energy values are also moderate. this is the result of very intense exogenetic processes which are predefined by the combination of existing specific lithology and climate. as the product of these specific set of conditions the badlands in central istria are very common isolated morphological landforms. a badland inventory of the research area, based on orthophoto pictures, contains 5568 identified badlands (poly­ gons). badlands in the research area are isolated landforms, and therefore very small, since the biggest has an area of 0.08 km2. badland area overall in the research area is 10.7 km2, which is 2.2 % of the total research area. badlands of central istria are also characterized by some sparse vegetation. generally, on all badlands of central istria there is strongly connected chain of exogenetic processes. in the chain of exogenetic processes most of exogenetic processes take place: weathering, denudation (erosion and mass movements on slopes), deposition or accumulation. the research results prove that the last link in the chain of exogenetic processes – erosion of the channel flow is the most important one, the link that defines the badland initiation, development and formation, i.e. close contact of the channel flow with the accumulated material at the badland slope foot is the most important factor in badland development and formation. as an argument for these statements, spatial analysis was undertaken on bedding orientation and cross section shape of the valley. analyses proved that both factors can influence the erosion by the channel flow, i.e. can dictate the concentration of channel flow at slope foot and conditions under which badlands can be formed. bedding orientation was analyzed at three locations: the south­eastern part or the ričica catchment area, st. donat badland catchment and boljun badland catchment. the analy­ sis showed that in the catchments with horizontal bedding (south­eastern part or the ričica catchment) badlands are equally developed on each slope, while on the catchments with inclined bedding (st. donat badland catchment and boljun badland catchment) badlands are developed on slopes which have the opposite aspect to bedding inclination. analyses of the cross section shape of the valley were undertaken on the botonega catchment where the ratio of badland increases from the mouth of the catchment towards the south-east border. the area of the cross section of the valley in that direction (north-west to south-east) is reduced, i.e. the valley width is smaller. this means that the cross section of the valley changes in shape from a u shape (higher order of valleys closer to the river mouth) to v shape (lower order of valleys more distant from the river mouth). the v shape of the valley influences the concentration of the channel flow at the slope foot which contributes to the badland formation and development. based on the present research, it can be concluded that close contact of the channel flow with the accumulated material at the badland slope foot is frequently the most important factor in maintaining an erosively active badland rockwall. therefore such situations, at locations of interest, should be artificially controlled or regulated if we wish to preserve fertile soil material and enable conservation of vege tation. references achten, w.m.j., dondeyne, s., samweli, m., elly, k., jean, p., jozef, d. & bart, m. (2008): gully erosion in south eastern tanzania: spatial distribution and topographic thresholds.– zeit­ schrift für geomorphologie, 52, 225–235. azo (2006): corine land cover.– baza podataka, agencija za zaštitu okoliša, zagreb. figure 17: analysis of 12 profile positions: a) correlation of the width of cross section and badland ratio for each segment b) correlation of the area of cross section and badland ratio for each segment. geologia croatica 67/1geologia croatica 14 bergant, s., tišljar, j. & šparica, m. (2003): eocen carbonates and flysch deposits of the pazin basin.– in: vlahović, i. & tiš­ ljar, j. (eds.): 22nd ias meeting of sedimentology – opatija. field trip guidebook, 57–63. boardman, j., parsons, a.j., hollandc, r., holmesc, p.j. & washingtond, r. (2003): development of badlands and gullies in the sneeuberg, great karoo, south africa.– catena, 50, 165–184. bryan, r.b., campbell, i.a. & yair, a. (1987): postglacial geomorphic development of the dinosaur provincial park badland, alberta.– canadian journal of earth science, 24, 135–146. bryan, r.b. & yair, a. (1982): perspectives on studies of badland geomorphology.– in: bryan, r.b. & yair, a. (eds.): badland geomorphology and piping. geobooks, norwich, 1–12. curry, a.m. & morris, c.j. (2004): lateglacial and holocene talus slope development and rockwall retreat on mynydd du, uk.– geo morphology, 58, 85–106. de ploey, j. (1974): mechanical properties of hillslopes and their relation to gullying in central semi­arid tunisia.– zeitschrift für geomorphologie supplementband, 21, 177–190. díaz­hernández, j.l. & juliá, r. (2006): geochronological position of badlands and geomorphological patterns in the guadix– baza basin (se spain).– quaternary research, 65, 467–477. eriksson, m., reuterswärd, k. & christiansson, c. (2003): changes in the fluvial system of the kondoa irangi hills, central tanzania, since 1960.– hydrological processes, 17, 3271–3285. feoli, e., gallizia vuerich, l. & woldu, z. (2002): pro cesses of environmental degradation and opportunities for rehabilitation in adwa, northern ethiopia.– landscape ecology, 17, 315–325. gajić­čapka, m., perčec tadić, m. & patarčić, m. (2003): digitalna godišnja oborinska karta hrvatske [digital annual map of precipitation of croatia – in croatian].– hrvatski meteorološki časopis, 38, 21–33. gams, i., zeremski, m., marković, m., lisenko, s. & bognar, a. (1985): uputstvo za izradu detaljne geomorfološke karte sfrj u razmeru 1:100.000 [manual for the production of detailed geomorphological map of sfry in scale of 1:100.000 – in serbian].– radna grupa naučnog veća međurepubličko­po krajin skog projekta za geomorfološko kartiranje, beograd, 80 p. gilbert, g.k. (1880): report on the geology of the henry mountains.– us geographical and geological survey of the rocky mountain region, 2nd editon, washington, dc, 170 p. gulam, v. (2012): erozija ogolina u flišu središnje istre [the erosion of flysch badlands in the central istria – in croatian].– doctoral thesis. faculty of mining geology and petroleum engineering, university of zagreb, 276 p. howard, a.d. (1994): badlands.– in: abrahams, a.d. & parsons, a.j. (eds.): geomorphology of desert environments. chapman &hall, london, 213–242. howard, a.d. (1997): badland morphology and evolution: interpreta­ tion using a simulation model.– earth surface processes and land­ forms, 22, 211–227. howard, a.d. & kerby, g. (1983): channel changes in badlands.– bulletin of the geological society of america, 94, 739–752. imeson, a.c., kwaad, f.j.p.m. & verstraten, j.m. (1982): the relationship of soil physical and chemical properties to the development of badlands in morocco.– in: bryan, r.b. & yair, a. (eds.): badland geomorphology and piping. geobooks, norwich, 47–70. joshi, v., tambe, d. & dhawade, g. (2009): geomorphometry and fractal dimension of a riverine badland in maharashtra.– journal of the geological society of india, 73, 355–370. juračić, m. (1980): dubina sedimentacije „lapora s rakovicama“ iz odnosa planktonskih i bentičkih foraminifera [depth of sedimenta­ tion of „marl with crabs“ estimated from the ratio between plank­ tonic and benthic foraminifera].– geološki vjesnik, 31, 61–67. jurak, v. & fabić, z. (2000): erozija kišom u slivu bujičnog vodotoka u središnjoj istri [torrential catchment raindrop erosion in the cetnral istria].– in: vlahović, i. & biondić, r. (eds.): zbornik radova 2. hrvatskog geološkog kongresa, cavtat – dubrov­ nik, 603–612. jurak, v., petraš, j. & gajski, d. (2002): istraživanje ekscesivne erozije na ogoljelim flišnim padinama u istri primjenom terestičke fotogrametrije [research into excessive erosion of bare flysch slopes in istria by use of terrestrial photogrammetry – in croatian].– hrvatske vode, 10/38, 49–58. liu, t., an, z., yuan, b. & han, j. (1985): the loess­palaeosol sequence in china and climatic historiy.– episodes, 8, 21–28. maerker, m., castro, c.p., pelacani, s. & baeurel, m.v.s. (2008): assessment of soil degradation susceptibility in the chaca­ buto province of central chile using a morphometry based response units approach.– geografia fisica e dinamica quaternaria, 31, 47–53. marković, m. (1983): osnove primenjene geomorfologije [basics of applied geomorphology – in serbian].– posebna izdanja, knjiga 8., geoinstitut, beograd, 174 p. ogrin, d. (2005): istarska enciklopedija [istrian encyclopedia – in croa tian].– in: bertoša, m. & matijašić, r. (eds.): leksikografski zavod miroslav krleža, zagreb, online edition (http://istra.lzmk. hr/clanak.aspx?id=1369). petraš, j., holjević, d. & patrčević, v. (2008): mjerenje produkcije erozijskog nanosa na istraživačkom poligonu „abrami“ u istri [measuring of the erosion sediment yield at the „abrami” re­ seach polygon in istria].– in: ožanić, n. (eds.): savjetovanje – hidrološka mjerenja i obrada podataka. nacionalni park plitvička jezera, 190–206. pleničar, m., polšak, a. & šikić, d. (1969): osnovna geološka karta sfrj, list trst u mjerilu 1:100 000 [basic geological map of sfry, sheet trieste in scale of 1:100.000 – in croatian and slovenian].– savezni geološki zavod, beograd. polšak, a & šikić, d. (1969): osnovna geološka karta sfrj, list rovinj u mjerilu 1:100.000 [basic geological map of sfry, sheet rovinj in scale of 1:100.000 – in croatian].– savezni geološki zavod, beograd. polšak, a. & šikić, d. (1973): osnovna geološka karta sfrj, tumač za list rovinj [basic geological map of sfry, guide for sheet rovinj – in croatian].– savezni geološki zavod, beograd. seong, y.b., owen, l.a., caffee, m.w., kamp, u., bishop, m.p., bush, a., copland, l. & shroder, j.f. (2009): rates of basin­wide rockwall retreat in the k2 region of the central karakoram defined by terrestrial cosmogenic nuclide 10be.– geomorphology, 107, 254–262. strahler, a.n. (1957): quantitative analysis of watershed geomorphology.– transactions of the american geophysical union, 38/6, 913–920. šikić, d., polšak, a. & magaš, n. (1969): osnovna geološka karta sfrj, list labin u mjerilu 1:100.000 [basic geological map of sfry, sheet labin in scale of 1:100.000 – in croatian].– sa vezni geološki zavod, beograd. šikić, d., pleničar, m. & šparica, m. (1972): osnovna geološka karta sfrj, list ilirska bistrica u mjerilu 1:100.000 [basic geolo­ gical map of sfry, sheet ilirska bistrica in scale of 1:100.000 – in croatian and slovenian].– savezni geološki zavod, beograd. velić, i., tišljar, j., vlahović, i., matičec, d. & bergant, s. (2003): evolution of the istrian part of the adriatic carbonate platform from middle jurassic to santonian and formation of the gulam et al.: the analysis of the flysch badlands inventory in central istria, croatia geologia croatica 15 flysch basin durnig the eocene: main components and regional com parison.– in: vlahović, i. & tišljar, j. (eds.): field trip guidebook, 22nd ias meeting of sedimentology, opatija. 3–17. vlahović, i., tišljar, j., velić, i., matičec, d., skelton, p. w., korbar, t. & fuček, l. (2003): main events receorded in the sedimentary succession of the adriatic carbonate platform from the oxfordian to the upper santonian in istria (croatia).– in: vla­ hović, i. & tišljar, j. (eds.): field trip guidebook, 22nd ias meeting of sedimentology, opatija. 19–56. vresk, m. (1987): polarizacijski efekti urbanizacije istre [polarization effects of the urbanization of istria – in croatian].– acta geogra­ phica croatica, 22, 43–53. wainwright, j. & brazier, r. (2011): slope systems.– in: thomas, d.s.g. (ed.): arid zone geomorphology. 3rd edition, 209–233. wainwright, j. (1994): anthropogenic factors in the degradation of semi­arid regions: a prehistoric case study in southern france.– in: millington, a.c. & pye, k.u (eds.): effects of environmental changes on drylands. john wiley & sons, ltd. chichester, 285–304. wainwright, j. & thornes, j.b. (2003): environmental issues in the mediterranean: processes and perspectives from the past and present.– routledge, london, 479 p. wise, s.m., thornes, j.b. & gilman, a. (1982): how old are the badlands? a case study from southeast spain.– in: bryan, r.b. & yair, a. (eds.): badland geomorphology and piping. geobooks, norwich, 259–277. zaninović, k., srnec, l. & perčec tadić, m. (2004): digitalna godišnja temperaturna karta hrvatske [a digital annual temper­ ature map of croatia – in croatian].– hrvatski meteorološki ča so­ pis, 39, 51–58. zorn, m. (2009a): erosion processes in slovene istria. part 1, soil erosion.– acta geographica slovenica, 49/1, 39–87. zorn, m. (2009b): erosion processes in slovene istria. part 2, badlands.– acta geographica slovenica, 49/2, 291–341. zorn, m. (2012): geomorphic activity in flysch badlands of the istria peninsula (sw slovenia).– zeitschrift für geomorphologie, suppl., 56/3, 53–79. manuscript received september 23, 2013 revised manuscript accepted december 18, 2013 available online march 21, 2014 gc_2-2013_kb.indd ab stra ct application of the sintacs method for assessment of the intrinsic vulnerability of an aquifer is demonstrated in the catchment areas of the jadro and žrnovnica springs. both springs provide drinking water, supplying the population of split and the surrounding settlements. rapid economic expansion in the catchment area, accompanied with an increasing trend in the quantity of a number of contaminants in the spring water, prompted comprehensive investigations in order to fi nalise the water management study of the jadro and žrnovnica springs. results of the study were analysed by gis tools and employed as input data for production of the groundwater vulnerability map of the jadro and žrnovnica catchment areas. in addition to the standard method of defi ning the c factor which, in this case, is represented by the values of c(a), a modifi cation is also introduced which takes into account analysis of sinkhole density. keywords: groundwater, intrinsic vulnerability, sintacs, karst, gis, jadro and žrnovnica  geologia croatica 66/2 119–128 7 figs. 2 tabs. zagreb 2013 geologia croaticageologia croatica assessment of aquifer intrinsic vulnerability by the sintacs method  sanja kapelj1, jelena loborec1 and janislav kapelj2 1 faculty of geotechnical engineering, university of zagreb, hallerova aleja 7, 42000 varaždin, croatia; (sanja.kapelj@zg.t-com.hr; jloborec@gfv.hr) 2 geo-rudus d.o.o., đ. popovića 13 – šimunčevec, 10360 sesvete, croatia; (janislav.kapelj@zg.t-com.hr) doi: 10.4154/gc.2013.09 1. introduction groundwater is the main source of potable water in many parts of the world including the republic of croatia, where approximately half of the country’s territory is covered by karstifi ed carbonate rocks, and the so-called dinaric type of karst. this is why the utmost caution must be paid explicitly to groundwater protection in karst aquifers. karstifi ed carbonate rocks are typically covered by a thin, irregularly distributed, soil layer, and are intersected by a multitude of interconnected fractures facilitating the rapid infi ltration of surface water. groundwater fl ows through the conduits and fi ssures with high velocity and with a relatively short retention time, allowing the quick and far-reaching spread of potential contamination from the surface. this is why karst aquifer systems are thought to be extremely vulnerable and easily threatened to various extents by each and every human activity. the concept of vulnerability is based on the premise that the physical properties of the environment offer a certain degree of protection to the groundwater with respect to human infl uence and ingress of contamination into the subsurface. vulnerability is a relative, unquantifi able, and non-dimensional property that may be either intrinsic or specifi c (vrba & zaporozec, 1994). intrinsic groundwater vulnerability takes into account the geologic, hydrologic and hydrogeologic properties of the area regardless of the characteristics of the pollutant, or the mode of contamination (zwahlen, 2004). one of the fi rst methods to assess the vulnerability of groundwater which is adjusted for the hydrogeologic, climatic, and social conditions of the mediterranean region was the sintacs method (civita & de maio, 2000). assessment of vulnerability using this method is based on the evaluation of seven key parameters vital for defi ning the pollution retention capacity, description of vertical fl ow to the water table and horizontal fl ow within the saturated zone which include: depth to groundwater, effective infi ltration, attenuation capacity in the unsaturated zone, attenuation capacity in the soil/sediment cover, hydrogeologic properties of the aquifer, hydraulic conductivity range of the aquifer and the hydrological role of the topographic slope. results of the vulnerability analysis are presented in the form of groundwater vulnerability maps. these maps are utilized prigeologia croatica 66/2geologia croatica 120 marily for groundwater management and protection in the particular area and as an irreplaceable background for decision making in management and land use. the area selected for assessment of intrinsic aquifer vulnerability by the sintacs method encompasses the catchment areas of the jadro and žrnovnica springs (fig. 1) located in the wider hinterland of the city of split. split is the largest city in dalmatia and the second largest in croatia with more than 180,000 people living in the town and its suburbs. it is also the second largest croatian port and the third largest in the mediterranean, based on passenger transport fi gures. the popularity of split as a tourist destination is constantly increasing (www.split.hr). based on the results of earlier investigations, the waters from the jadro and žrnovnica springs are perceived as being of great importance with regard to the water supply needs of the local population, as well as being increasingly vulnerable due to economic growth. the catchment area is mostly composed of permeable carbonate rocks which signifi cantly complicate protection of the water reserves. construction of business zones within the catchment, the absence of wastewater systems in the expanding settlements, and construction of roads adversely affect the active protection of groundwater, causing possible degradation. since the groundwater reserves in the catchment are of invaluable natural and economic worth for the city of split and its surrounding area, effi cient protection is a mandatory requirement given the simultaneous economic development of the entire region. the sintacs model of intrinsic vulnerability assessment has previously been tested throughout italy (civita & de maio, 2000); corniello et al., 2004; polemio et al., 2009), in selected parts of slovenia (janža & prestor, 2002; mali & janža, 2005; uhan et al., 2008) and spain (longo et al., 2001), regarding the aquifers with intergranular and karst and fi ssured porosity. 2. area of investigation the jadro and žrnovnica springs are located in the foothills of the mosor and kozjak mts. in the contact zone between the splitska zagora carbonate sedimentary rocks of good permeability and the coastal fl ysch belt. jadro is situated at an altitude of 35 m a.s.l., while žrnovnica lies at the altitude of 90 m a.s.l. according to the available hydrological data, the minimum discharge of the jadro spring ranges between 3.60 m3/s (august 1995) and 3.90 m3/s (september 1997, august and september 2003). it is at its lowest in the dry period, mostly in august and september, when the mean monthly discharge may decrease to only 4.0m3/s (august 1995, and september 2003). during the dry period water abstraction from the jadro spring often exceeds the permissible 2.0 m3/s, rising up to 2.9 m3/s, kapelj et al. (2006)1. figure 1: location of the catchment. 1 kapelj, s., kapelj, j., biondić, r., biondić, b., kovač, i., tušar, b., prelogović, e., marjanac, t., andrić, m., kovačić, d., strelec, s. & gazdek, m. (2006): studija upravljanja vodama sliva jadra i žrnovnice – prva faza studijsko istraživačkih radova [water management study of the jadro and žrnovnica springs recharge area, fi rst phase – in croatian].− evv: 1/2005. hrvatske vode, split, 147 p. kapelj s. et al.: assessment of aquifer intrinsic vulnerability by the sintacs method geologia croatica 121 žrnovnica joins several smaller springs upwelling in the broader area. the minimum measured discharge of this spring area is up to 250 l/s (september 9th 1993) while the maximum discharge is up to 19.1m3/s (december 18th 2004). the jadro spring is used for the water supply of split, surrounding settlements and the towns of solin, kaštela and trogir. žrnovnica is used for the water supply of the village of žrnovnica and irrigation of agricultural areas. according to the data available from the earlier hydrogeological research, the catchment area of the jadro and žrnovnica springs varied between 300 and 500 km2 depending on the authors (bonacci, 1978)2 and (fritz et al., 1988)3. this particularly relates to the defi nition of the eastern and western watersheds, since the northern and southern borders of the catchment are much easier to determine, being the contact with impermeable sediment functioning as a complete hydrogeological barrier. according to more recent research, (since 2000), and especially on the grounds of groundwater tracing tests results, the eastern and western watersheds have been redefi ned, since the infl uence of the contiguous catchments and signifi cant contribution of contiguous rivers (krka river from the west and cetina river from the east) have been determined. this is substantiated by the fact that the žrnovnica, in natural conditions, was an intermittent spring, which dried up in times of drought, but after construction of dams on the cetina river for he đale, has become a permanent spring. the catchment area is predominantly composed of carbonate rocks, limestone and dolomite, and fl ysch sediments, while other rocks occur more rarely. four main categories figure 2: hydrogeologic map of the study area. 2 bonacci, o. (1978): hidrogeološka studija žrnovnice.− [hydrogeological study of žrnovnica − in croatian]. – unpubl. report. arhiva građevinskog instituta, split. 3 fritz, f., pavličić, a., renić, a. & kapelj, j. (1988): izvori jadro i žrnovnica. dio hidrogeoloških istražnih radova potrebnih za prijedlog zona sanitarne zaštite [jadro and žrnovnica springs. part of the hydrogeological investigation works required for the proposal of sanitary protection zones – in croatian].− unpubl. report. arhiva hgi 140/88, zagreb. geologia croatica 66/2geologia croatica 122 of rocks are distinguished according to their permeability on the hydrogeological map of the catchment area (fig. 2): permeable rocks – includes permian, mesozoic and partly eocene carbonate rocks (dark green), moderately permeable rocks – this group includes dolomitic limestones and dolomites of cenomanian and platey limestones of turonian age (medium green), poorly permeable rocks – this group comprises permian argillaceous limestones, anisian dolomite, clastic rocks and breccia, marly limestones and calcareous marls of palaeocene age (light green), and impermeable rocks – the clastic deposits of the lower triassic and eocene fl ysch (brown). in addition, a subgroup of sedimentary rocks of alternating properties has also been identifi ed. these sediments originated by aerial weathering of the parent rocks or deluvial processes on the slope material. they contain siltyclayey materials with various limestone rock fragments. local cultivable areas contain a substantial amount of sand. the latter can be found in karst poljes, river valleys and in local depressions in general. in the interpretation of the basic hydrogeological map of the croatian republic (split and primošten sheets), fritz & kapelj (1998) provided a detailed description of the hydrogeological characteristics of the rocks observed in this area. a variety of different karst phenomena can be found in the catchment area. distinct terrain fracturing paved the way for the intense karstifi cation of carbonate rocks. no perennial fl ows are formed on the carbonate bedrock meaning all rainfall sinks underground over a short time interval. in parts of the catchment where clastic rocks are present, there are intermittent surface water fl ows which quickly converge on single sinkholes occurring in the karst poljes and therefore enter into the zones of horizontal circulation of groundwater kapelj et al. (2008)4. 3. sintacs method the sintacs method of vulnerability assessment is based on evaluation of the following parameters (civita & de maio, 2000): – depth to groundwater, – impact of effective infi ltration, – capacity of attenuation in the unsaturated zone, – capacity of attenuation in the soil/sediment cover, – hydrogeologic properties of the aquifer, – hydraulic conductivity range of the aquifer, – hydrological role of the terrain slope. parameters of the sintacs model are converted using the suggested diagrams, tables, ranges and computation into s, i, n, t, a, c and s parameters, each in the range of values between 1 and 10, where the higher value denotes greater aquifer vulnerability. a. parameter s – depth to groundwater depth to groundwater represents the distance from the surface to groundwater level or for a confi ned aquifer, the thickness of sediments overlying the aquifer. it is important for vulnerability assessment because it infl uences the fi ltration time of contaminated fl uid. according to the model assessment rating, a greater depth means a less vulnerable aquifer. b. parameter i – impact of eff ective infi ltration effective infi ltration represents the amount of water which reaches the aquifer from the surface. it is important for vulnerability assessment, due to its role in the infi ltration of pollution from the surface and dilution of contaminants during transport through the unsaturated and saturated zones. calculation of the parameter values is based on precipitation (p) and evapotranspiration (et) (a series of at least 20 mean annual precipitation and mean annual air temperature results) combined with surface hydrogeological conditions, as contained in the potential infi ltration index (χ – theta) (eq.1). i = (p – et) · χ (1) c. parameter n – attenuation capacity in the unsaturated zone the unsaturated zone is important for vulnerability assessment because it represents protection of the aquifer against the contaminated fl uid. physical and chemical processes operate within the unsaturated zone diluting the contamination. in as much as the unsaturated zone contains beds with different lithological and hydrogeological characteristics in vertical distribution; relating a value to the zone thickness is calculated as the sum of the products between depth and weight of each separate bed divided by the total thickness of the unsaturated zone. d. parameter t – attenuation capacity of the soil/sediment cover soil and sediment cover function very effi ciently in slowing or retaining the contaminated fl ow through the hydrogeologic system and thus assume a very important role in vulnerability assessment. soil is often represented as an environment suitable for the accumulation and transformation of matter. it is therefore necessary to study two groups of parameters: fi rst, those affecting the physical characteristics (grain size, texture, porosity, hydraulic conductivity…), and secondly the parameters that affect absorption ability (ph, cation exchange capacity (cec), organic matter content and amount of clay). since the data needed for assessment of parameter t are commonly unavailable and restricted to granu4 kapelj, s., kapelj, j., marjanac, t., prelogović, e., cvetko-tešović, b., biondić, b., ivanković, t., jukić, d. & denić-jukić, v. (2008): studija upravljanja vodama sliva jadra i žrnovnice – druga faza studijsko istraživačkih radova [water management study of the jadro and žrnovnica springs recharge area, second phase – in croatian].− evv:9/2007. hrvatske vode, split, 122 p. kapelj s. et al.: assessment of aquifer intrinsic vulnerability by the sintacs method geologia croatica 123 lometric composition and texture, rating diagrams refer particularly to these soil characteristics. e. parameter a – hydrogeologic properties of the aquifer for assessing groundwater vulnerability, hydrogeologic properties of the aquifer are related to the processes within the saturated zone. those processes are: molecular and kinematic dispersion, dilution, sorption, and chemical reactions between bedrock and contaminants. hydrogeologic investigations collate all the available information on lithology, structure, fracturing and karstifi cation of the saturated zone, offering a single database necessary to assess all facets of aquifer vulnerability. based on the available data, and using default ranges in the rating diagrams, the user may choose a satisfactory value for each cell within the aquifer. f. parameter c – hydraulic conductivity range of the aquifer hydraulic conductivity is defi ned as the ability of an aquifer to transmit the water inside the saturated medium, or from the viewpoint of vulnerability assessment, mobility of contamination the density and viscosity of which are equal to that of water. assessment and zoning of this parameter is extremely diffi cult, especially if there are no available data from fi eld research. assessment diagrams needed for allocation of parameter c values are related to the coeffi cient of conductivity (k). g. parameter s – hydrological role of the terrain slope terrain slope is a very important factor in vulnerability assessment because it defi nes the surface runoff as a part of precipitation, and thus determines the areas in which there is a greater possibility for contaminants to infi ltrate from the surface into the aquifer. greater values of the s parameter are allocated to gentler slopes or the fl attened parts of the terrain due to the reduced possibility for contamination spread (dissemination) due to gravity. besides, the terrain slope can be an indicator of the soil type and thus indirectly determines the capacity of the hydrogeologic system to retain contamination. 4. defining the sintacs parameters for the jadro and žrnovnica catchments data collected in the jadro and žrnovnica catchment basins were treated by gis using esri arcgis software. data were saved in the database from which the layers were generated in vector and raster form, (hydrogeologic units, digital elevation model, depth to groundwater, geomorphologic objects, precipitation). these were later processed separately and supplemented by a spatial overlay with the necessary attributes and fi nally classifi ed for each of the seven given parameters – s, i, n, t, a, c, s. according to numeric values of the individual parameters, the vector layers were converted into the raster grid format, with a cell resolution of 25 m for each separate parameter (fig. 4). the fi nal result was obtained by mapping algebra (raster calculator in extension of spatial analyst) using the combination of grids. this was the map of intrinsic aquifer vulnerability in the catchment area of jadro and žrnovica. parameter s – depths to groundwater for most of the jadro and žrnovica catchment areas were estimated at more than 100 m except for that measured at dugopolje (40 m), and assumed in the bisko polje (70 m). adequate values were added to the vectorized polygons in these poljes according to rating diagrams of the s factor of 2 and 1.3. for the remaining area extending to the border of the jadro-žrnovnica catchment, where the depth to groundwater exceeds 100 m, a value of 1 was assigned to the s parameter. parameter i – effective infi ltration in the catchment area is computed according to the precipitation and evapotranspiration data in zaninović et al. (2008) which combined with parameters for particular lithologic units yielded the specifi c values based on the rating diagrams of the i factor. the values of 4.5 have been assigned for permeable carbonate rocks; 3 for low permeable rocks (fl ysch), and 6.8 for quaternary cover sediments to the polygons defi ned on the hydrogeological map. parameter n – the attenuation capacity in the unsaturated zone is calculated for quaternary terrains covered with soil and for other areas without the soil cover. it is defi ned according to the rating diagram and added to the lithology, explicitly to the permeability value of the specifi c area. for those parts of the terrain covered with quaternary sediments, figure 3: the map of sinkhole density. nevertheless, the density of sinkholes is used as an additional indicator of groundwater transmission in this case. sinkholes are one of the key elements indicating the intensity of karstifi cation of carbonate sedimentary rocks. they were digitized as points from topographic maps m 1:25000 (10312 individual objects were singled out). after analyzing the density of sinkholes as the number of sinkholes in a 250x250 m area, the spatial distribution of sinkholes was calculated yielding the map of sinkhole density containing 5 density classes (fig. 3). geologia croatica 66/2geologia croatica 124 figure 4: layer display representing specifi c parameters. kapelj s. et al.: assessment of aquifer intrinsic vulnerability by the sintacs method geologia croatica 125 the following values were calculated: dugopolje – 7.7, bisko polje – 8.0, dicmo and konjsko– 9.0, blaca – 9.5, and muć 10.0. high values of parameter n on the karst poljes, where silty-clayey materials should provide better aquifer protection, can be interpreted as being due to thin surface sediments, beneath which very permeable and thicker carbonate rocks occur. permeable carbonate rocks are rated as 10.0, moderately permeable as 8.0, poorly permeable as 7.0, low permeable fl ysch areas as 2.0, and low permeable areas with igneous rock as 1.0. parameter t – the rates of soil and sediment cover capacities is rated for the quaternary sediments in the karst poljes as 1.5, while for the rest of the catchment area with almost no cover whatsoever as 10.0. parameter a – hydrogeologic features of the aquifer depend on the hydrogeologic properties of the related rocks by which they are represented. for quaternary areas and karst poljes the factors are assessed according to the bedrock. permeable rocks are ascribed the value of 10, moderately permeable as 8, poorly permeable 7, and those of low permeability as 2. polygons are converted into grids with cells assuming the values of parameter a. parameter c – hydraulic conductivity of the aquifer was rated using three methods. the default, according to the sintacs method is defi ned using the hydrogeological properties of the rocks with assigned c factor values scanned from the rating diagram. permeable rocks are rated 10, moderately permeable are rated 7, poorly permeable 5, and those of low permeability as 2. the value of 10 is given to the area covered with quaternary sediments, because they are relatively thin and very permeable carbonate rocks lie beneath them. according to the c factor values the polygons were converted into a c(a) grid with cells having the afore-mentioned values. in the second case, parallel to the default rating method of the c factor, which is hereby represented by a c(a) value, a modifi cation is introduced taking sinkhole density into account. spatial analysis of the sinkhole density in an area 250x250 m, resulted in the defi nition of 5 classes with assigned values of the c factor (fig. 3): a density of >10 sinkholes is rated 10, 6–10 sinkholes is 9, 3–6 sinkholes is 7, 1–3 sinkholes is 5, and 0 sinkholes is 2. the c(b) grid is then created with c factor values determined according to the sinkhole density. using spatial overlaying of the c(a) and c(b) layers, a new raster is generated applying the higher value of c(a) or c(b) for each grid cell as a fi nal value of the c parameter. here, the role of the c(b) parameter was to additionally increase the vulnerability of the investigated area on the account of high sinkhole density which, for the c(a) factor, is obtained solely on the grounds of the rock properties. in the third case, the c parameter value is obtained by a different combination of c(a) and c(b) factors. the values in the c(a) and c(b) raster cells are the same as in the previous cases, but in the fi nal version of the modifi ed sintacs r5 method for c grid, the raster used is calculated as (c(a) + c(b))/2. parameter s – terrain slope in the form of a grid and with cell values according to the slope percent (%) is created by the surface analysis based on the digital slope relief at 25m resolution. slopes are classifi ed in 10 groups with ranges of: 0–2, 2–4, 4–6, 6–9, 9–12, 12–15, 15–18, 18–21, 21–25 and >25 %. grid is reclassifi ed and dependent on slope assigned with values 10, 9, 8, 7, 6, 5, 4, 3, 2 and 1, the values of s parameter. the cell values 10 for the slope 0–2, 9 for the slope 2–4, 8 for 4–6, etc. 5. results the jadro and žrnovnica catchment areas belong to the typical karst of the outer dinarides (kapelj et al., 2009)5 and the sintacs method introduces for these areas the weighted factors for each of the component grids of a specifi c parameter. the result is the sum of grids enlarged by the weighted parameters. the weighted parameters applied in karst areas for the sintacs parameters are as follows: s -2; i-5; n-1; t-3; a-5; c-5 and s-5 (civita & de maio, 2000). based both on the grids of the sintacs method and the weighted parameters, the grids were created with indices of intrinsic vulnerability. the vulnerability index iv is classifi ed as ranges giving the degree of intrinsic vulnerability, as represented in table 1. three variations of the sintacs method were used in order to calculate the degree of aquifer vulnerability in the jadro and žrnovnica catchment areas. in the fi rst case, the default value from the diagram was used for the c parameter table 1: classes of intrinsic vulnerability. vulnerability index (iv) degree of intrinsic vulnerability 26–80 very low 80–105 low 105–140 medium 140–186 high 186–210 very high 210–260 extreme 5 kapelj, s., kapelj, j., dogančić, d., loborec, j., ivanković, t., cvetko-tešović, b. & milanović, d. (2009): studija upravljanja vodama sliva jadra i žrnovnice – treća faza studijsko istraživačkih radova [water management study of the jadro and žrnovnica springs recharge area, third phase – in croatian].− evv:21/2008. hrvatske vode, split, 59 p. geologia croatica 66/2geologia croatica 126 (eq.2). in the second case the c parameter was computed after the modifi ed method which includes the infl uence of sinkhole density. the higher value in combination c(a) or c(b) was then used as a fi nal result (eq.3). finally, in the third case the c factor was calculated according to the formula: (c(a)+c(b))/2 (eq.4). results of the computation were displayed in the form of vulnerability maps. calculation of the aquifer vulnerability indices by the standard sintacs method produced the weighted factors for karst: iv(sintacs r5) = s*2+i*5+n*1+t*3+a*5+c*5+s*5 (2) calculation of the aquifer vulnerability index according to the modifi ed sintacs method (including sinkhole density) and weighted factors for karst gives: iv(sintacs 1.modifi cation) = s*2+i*5+n*1+t*3+a*5+(ca or cb)*5+s*5 (3) calculation of the aquifer vulnerability index according to the modifi ed sintacs method (including sinkhole density) and weighted factors for karst equals: iv(sintacs 2.modifi cation) = s*2+i*5+n*1+t*3+a*5 +((ca+cb)/2)*5+s*5 (4) for each map, intrinsic vulnerability was calculated for the part of the catchment occupied by a specifi c class, and for the part of the total catchment area that it represents. results are displayed in table 2. from the above data it is obvious that sinkhole density affects the assessment of intrinsic aquifer vulnerability in the karst area. it is well known that areas with greater sinkhole density indicate a higher degree of karstifi cation. these areas represent the potential zones of more rapid underground infi ltration of water thus indicating greater aquifer vulnerability. for this particular reason, the new factor c(b) was introduced modifying parameter c. in the fi rst modifi cation, the idea was to enhance the c parameter value in those parts which, in accordance with the rock type, do not exhibit high values of the c parameter scanned from the rating diagram, but are characterized by a high number of sinkholes. however, results shown in table 2 indicate signifi cant overlap of these two conditions. namely, the maximum c parameter value is already present in the greater proportion of the catchment due to the presence of very permeable karstifi ed carbonate rocks. thus the lower contribution of the sinkhole density generates a trifl ing difference between the standard sintacs r5 and modifi ed sintacs methods. in the second modifi cation the c(a) and c(b) factors were combined in a different way. it is precisely because the major part of the catchment is composed of the very permeable limestones exhibiting the maximum value of the c parameter (10) that the idea originated to differentiate these large areas by introduction of the factor of the sinkhole density dependent on density classes. thus the maximum value of the c parameter is present only in those portions of the catchment where maximum values of c(a) and c(b) factors are overlapping, while elsewhere the value of the c parameter is represented by the arithmetic mean of the c(a) and c(b) parameters. therefore, in the second modifi cation of the sintacs method the area of classes of very high and extreme vulnerability decreased, while that of high and medium vulnerability increased (table 2). figure 5: map of intrinsic aquifer vulnerability according to the standard sintacs method and weighted factors for karst. figure 6: map of intrinsic aquifer vulnerability according to the modifi ed sintacs method (including sinkhole density) and weighted factors for karst (1. modifi cation). figure 7: map of intrinsic aquifer vulnerability according to the modifi ed sintacs method (including sinkhole density) and weighted factors for karst (2. modifi cation). kapelj s. et al.: assessment of aquifer intrinsic vulnerability by the sintacs method geologia croatica 127 table 2: the catchment area ratio.   sintacs r5 sintacs – 1.modification c=ca or cb sintacs –2.modification c=(ca+cb)/2 class area (km2) part of the catchment area (%) area (km2) part of the catchment area (%) area (km2) part of the catchment area (%) very low 8.38 1.48 8.59 1.52 8.61 1.52 low 7.55 1.33 7.41 1.31 7.42 1.31 medium 28.34 4.99 27.73 4.89 88.64 15.63 high 352.32 62.14 351.22 61.95 391.14 68.99 very high 149.20 26.32 150.69 26.58 70.43 12.42 extreme 21.18 3.74 21.28 3.75 0.74 0.13 6. conclusion application of the sintacs method in assessment of the intrinsic vulnerability of the aquifer system in the karst areas is presented here, using the example of the jadro and žrnovnica catchment. the sintacs method is based on evaluation of seven parameters describing the geologic, hydrogeologic and hydrologic conditions that directly affect aquifer sensitivity to the infl uence of human activity leading to contamination of groundwater. the sintacs method allows a large range of values for assessment of each parameter. also, it can be applied in every type of aquifer, due to the weighting strings which allow the model to adapt to different hydrogeological conditions. it is therefore extremely important to have good knowledge of the study area when determining the parameter values. this example is used in order to adjust the sintacs method to the conditions of the dinaric karst, typifi ed by its exceptional karstifi cation and it’s richness of landscape morphologies (sinkholes in particular). this is why certain modifi cations were introduced into the method itself with the purpose of suggesting an optimal approach to the assessment of vulnerability of the groundwater in the karst, based on comparison of the acquired results. based on the calculations (table 2) where the magnitudes of vulnerable areas are assessed by the standard sintacs method and by the modifi ed methods, taking into account the sinkhole density (fig. 6 and fig. 7), it is possible to draw several conclusions as follows: sinkhole density affects the intrinsic vulnerability of a karst aquifer. obviously, the sinkhole density increases the permeability of the lithologic members in certain parts of the terrain, and also affects the value of the vulnerability index. the combination of parameter c(a) (obtained using charts of the classical sintacs method and is dependent on the hydraulic conductivity of the aquifer) and parameter c(b) (obtained through an analysis of sinkhole density), in the expression of the mean (c(a)+c(b))/2, allows extraction of those parts of the catchment that are extremely vulnerable according to both indicators. as a result, those parts of a terrain assigned very high and extreme vulnerability indices, are reduced in area while those with high and medium vulnerability indices are increased. therefore, the isolated areas showing higher sinkhole density, (a very sensitive indicator of karstifi cation, or rock permeability), indicate the most vulnerable areas that need high protection. however this also raises the possibility of enlarging the exploitative areas in the karst that can be suitable for different uses to those areas having medium, low and very low vulnerability indices. acknowledgment the authors acknowledge the croatian waters and ministry of science, education and sport of the republic of croatia, who fi nancially supported the research through the projects “water management study of the jadro and žrnovnica springs recharge area”, 2005.–2012. and “sensitivity of the karst hydrogeological systems”, no. 160-0382709-1709, 2007-2009. we are also grateful to the journal’s associate editor and anonymous reviewers whose suggestions and comments improved the paper signifi cantly. references civita, m. & de maio, m. (2000): sintacs r5, a new parametric system for the assessment and automating mapping of groundwater vulnerability to contamination.– pitagora editor, bologna, 226 p. corniello, a., ducci, d. & monti, g.m. (2004): aquifer pollution vulnerability in the sorrento peninsula, southern italy, evaluated by sintacs method.− geofi s. int., 43/4, 575−581. fritz, f. & kapelj, j. (1998): osnovna hidrogeološka karta republike hrvatske 1:100 000, listovi split i primošten [basic hydrogeological map of the republic of croatia 1:100 000, sheets split and primošten – in croatian].− institut za geološka istraživanja, zagreb. janža, m. & prestor, j. (2002): ocena naravne ranjivosti vodonosnika v zaledju izvira rižane po metodi sintacs [intrinsic vulnerability assessment of the aquifer in the rižane spring chatchment by the method sintacs – in slovenian].− geologija, ljubljana, 45/2, 401−406. longo , a., andreo, b., carrasco, f., cucchi, f., vias, j. & jiménez, p. (2001): comparison of two contamination vulnerability maps obtained by the sintacs method in two carbonate aquifers (s spain).− 7th conference on limestone hydrology and fissured media. besançon, francia, 233−236. mali, n. & janža, m. (2005): ocena ranjivosti vodonosnika s sintacs modelom v gis okolju [a gis based sintacs model for assessing aquifer vulnerability – in slovenian].− geologija, 48/1, ljubljana, 127 140. polemio, m., casarano, d. & limoni, p.p. (2009): karstic aquifer vulnerability assessment methods and results at a test site (apulia, southern italy).− nat. hazard. earth. sys., 9, 1461−1470. uhan, j., pezdič, j. & civita, m. (2008): assessing groundwater vulnerability by sintacs method in the lower savinja valley, slovenia.− rmz-materials and geoenvironment, 55/3, 363−376. geologia croatica 66/2geologia croatica 128 vrba, j. & zaporozec, a. (1994) (eds): guidebook on mapping groundwater vulnerability. international contribution to hydrogeology.− (iah), hannover, 131 p. zaninović, k., gajić-čapka, m., perčec tadić, m., vučetić, m., milković, j., bajić, a., cindrić, k., cvitan, l., katušin, z., kaučić, d., likso, t., lončar, e., lončar, ž., mihajlović, d., pandžić, k., patarčić, m., srnec, l. & vučetić, v. (2008): klimatski atlas hrvatske, 1961.–1990.: 1971.–2000 [the climate atlas of croatia 1961.– 1990.: 1971.–2000.– in croatian].− dhmz, zagreb, 200 p. zwahlen, f. (2004) (ed.): vulnerability and risk mapping for the protection of carbonate (karst) aquifers. european commission, directorate – general for research, european research area: structural aspects – cost 620, 279 p. manuscript received july 31, 2012 revised manuscript accepted april 08, 2013 available online june 19, 2013 ab stra ct the mollusc fauna from the pliocene viviparus beds of vukomeričke gorice hills in central croatia was investigated at four sites in the region of kravarsko, s of zagreb. the region represents a pleistocene horst-anticline at the southern margin of the sava depression. sediments are dominated by clay, bearing some sand, gravel and lignite intercalations. the molluscs, comprising 11 gastropod and 2 bivalve species, seven of which (76.9%) are endemic to the region, prove that the studied deposits were derived from the ancient lake slavonia. the taxonomic revisions include the introductions of viviparus kochanskyae n. sp. for specimens from lake slavonia previously identified as v. fuch­ si neumayr, 1872 and prososthenia? praeslavonica n. nom. replacing the primary homonym hydrobia vitrella brusina, 1897 non stefanescu, 1896. recognized as an independent phase in the geodynamic evolution of the pannonian basin, the new regional stage cernikian is introduced for the succession, defined by the complete depositional sequence of the viviparus beds. two stratigraphic horizons detected in the studied sites are constrained by the lower cernikian viviparus kochanskyae and the upper cernikian viviparus hoernesi zones and remain in good agreement with previous regional data. the historical timeline for lake slavonia is enabled through several zonal markers calibrated to the geological time scale in the dacian basin. accordingly, the early cernikian transgression dates to c. 4.3 ma, the late cernikian transgression to c. 3.1 ma, indicating strong alteration of the lacustrine depositional settings during the pliocene, most likely related to changes in the regional climate. interestingly, the second transgression of lake slavonia is marked by the evolution of strongly sculptured viviparid shells and coincides with the pliocene climate optimum. keywords: lake slavonia, pliocene, paludina beds, mollusc taxonomy, stratigraphy  1. introduction the climatic and geodynamic settings during the pliocene provided conditions facilitating extended lacustrine environments in southeastern europe (neubauer et al., 2015a, c). the resulting long-lived palaeo-lakes such as lakes slavonia, metohia, transylvania and dacia were all characterized by explosive adaptive radiations of viviparid snails (harzhauser & mandic, 2008; neubauer et al., 2015a). this phenomenon allowed neumayr & paul (1875) in their famous, pioneering study on lake slavonian molluscs to establish a regional biostratigraphy, enabling an excellent stratigraphic control of those deposits stretching over more than 600 km along the southern margin of the pannonian basin. the present investigation deals with the corresponding mollusc record of lake slavonia (figure 1). the samples originate from the region of kravarsko, which is the type locality of several species described by brusina (1874a, b, geologia croatica 68/3 179–207 9 figs. 3 tabs. zagreb 2015 stratigraphic and palaeogeographic significance of lacustrine molluscs from the pliocene viviparus beds in central croatia  oleg mandic1*, tomislav kurečić2, thomas a. neubauer1 and mathias harzhauser1 1 geological-palaeontological department, natural history museum vienna, burgring 7, 1010 wien, austria; (corresponding author: oleg mandic (oleg.mandic@nhm-wien.ac.at)) 2 croatian geological survey, sachsova 2, hr-10000 zagreb, croatia doi:10.4154/gc.2015.15 geologia croaticageologia croatica geologia croatica 68/3geologia croatica 180 figure 1: map illustrating the recon­ structed extent of the pliocene lake slavonia (light blue) adapted from neubauer et al. (2015a); viviparus beds (dark blue) are redrawn from the geological map of the croatian geological survey m 1:300,000; pan­ nonian basin infill (gray) is redrawn from the previous map and from the yugoslavian geological map m 1:500,000; srtm topographic mo­ del is the arcgis world shaded relief map by esri. white dots indicate stu­ died localities and the type localities of the cernikian defined in the pre­ sent study. by the end of the middle miocene, the paratethys sea retreated and the remaining brackish lake pannon gave rise to spectacular endemic mollusc radiation in the late miocene (müller et al., 1999; harzhauser & mandic, 2008; neubauer et al., 2015a, c). isolation lasted up to 6.04 ma when the connection with the dacian basin becomes established during the early pontian (stoica et al., 2013), followed by the migration of the endemic fauna into the eastern paratethys (stevanović et al.,1990). with the onset of the pliocene, lake pannon was largely infilled by sediment due to the prograding river systems of the palaeo-danube and palaeo-tisza and became restricted in its ultimate phase to ne croatia and n serbia (magyar et al., 1999, 2013; uhrin & sztanó, 2012). during a new period of isolation from the dacian basin in the late dacian, it became replaced by the freshwater environment of lake slavonia (stevanović et al.,1990; marinescu & papaianopol, 1995). the initiation of lake slavonia is marked by a major extinction event of brackish water dwellers such as congeria rhomboidea hörnes, 1870, phyllocardium planum (deshayes, 1838) or prosodacnomya? vodopici (brusina, 1902) (neumayr & paul, 1875; stevanović et al., 1990). the succession documenting the rapid endemic radiation of viviparid snails is consequently termed the vivi­ parus beds. the lake slavonia deposits extend from the studied region to westernmost romania, infilling the sava, slavonian-syrmian, bačka and banat depressions of the southern pannonian basin (figure 1). the threefold stratigraphic classification into the lower, middle and upper vivi­ parus beds is well established throughout the region, supported by the biostratigraphic zonation of viviparus species (neumayr & paul, 1875; penecke,1884; jenko, 1944; ožegović, 1944; takšić, 1954; marinescu & papaianopol, 1995; lubenescu & lubenescu, 2008). the upper boundary is marked by the establishment of alluvial depositional settings marked by the pleistocene corbicula beds in the slavonian-syrmian, bačka and banat depressions, dated to ~2 ma (gaudenyi et al., 2013, 2015). the investigated region (figure 1) represents the southern margin of the sava depression, a nw-se striking extensional structure filled by more than 5 km of predominantly siliciclastic neogene deposits (troskot-čorbić et al., 2009). the sedimentary infill of the sava depression (figure 1897, 1902). situated in central croatia, in the close vicinity of zagreb, it represents the western most extent of the palaeo-lake. freshwater deposits alternate therein with alluvial series, providing an approximately 400 m thick plio cene continental succession (galović, 1952). the series is usually referred to in the literature as the “paludina beds” (krstić, 2003; popov et al., 2004). paludina férussac, 1812, however, is a junior synonym of viviparus mon tfort, 1810, which is why we use the term “viviparus beds” in the present study. note that this is only an informal lithostratigraphic unit according to the international stratigraphic code (salvador, 1994). the aim of the study is to investigate and document the taxonomic inventory of the region, to update the taxonomy of the identified species, and to evaluate the resulting biostratigraphic and palaeo biogeographic patterns for lake slavonia and the neighbouring palaeo-lakes. additionally, the outdated late miocene to pliocene stratigraphic nomenclature of the sava depression sedimentary series is revised and a new stage name is introduced, constrained by the depositional duration of the viviparus beds and lake slavonia, respectively. 2. southern pannonian basin and sava depression the pannonian back-arc basin is a large neogene extensional structure located between the alpine, dinaride and carpathian fold-and-thrust belts in central and se europe (schmid et al., 2008; ustaszewski et al., 2014). its formation is bound to the rapid miocene roll-back of the carpathian (and probably dinaride) slab attached to the european continent, and to the adriatic microplate, respectively (matenco & radivojević, 2013). the initiation of the synrift phase is marked by the first alluvial and lacustrine deposition in its southern domain dated to ~18 ma (early miocene). its marine ingression by the central paratethys clearly followed later at ~15 ma in the middle miocene (ćorić et al., 2009; mandic et al., 2012) (figure 2). in northeastern croatia, the post-rift deposition had already begun at ~13.8 ma in the late badenian and continued throughout the middle–late miocene (pavelić, 2001). the area of north croatia experienced strong compressional uplifting in the pliocene and pleistocene that caused erosion and reworking of the miocene deposits and exhumation of the pre-miocene basement (pavelić, 2001). mandic et al.: stratigraphic and palaeogeographic significance of lacustrine molluscs from the pliocene viviparus beds in central croatia geologia croatica 181 figure 2: chronostratigraphic cor­ re lation table for the late neogene indicating the stratigraphic posi­ tions of the units referred to in the present study. standard chronostra­ tigraphy derives from hilgen et al. (2012). compilation of paratethys re gional stages is adapted from neu bauer et al. (2015b). palaeoge­ ographic connection events are mark ed by arrows. the cernikian is a new pannonian basin stage defin­ ed in the present study. tion of lake slavonia. in the sava depression, the pannonian is four-fold, composed of the radix cro­ atica, congeria banatica, paradacna abichi and congeria rhomboidea beds (jenko, 1944; lučić et al., 2001). hitherto, the p. abichi and the c. rhom­ boidea beds were correlated with the pontian eastern paratethys stage (stevanović, 1951; steva no vić et al., 1990; lučić et al., 2001). however, such correlation is shown to be incorrect. in the pannonian basin, volcanic ash on top of the lower “pontian” deposits in the vicinity of tihany (central hungary), correlates with the top of the p. abichi beds, revealing an 40ar/39ar calibration point of 7.95 ma (wijbrans et al., 2007; magyar & geary, 2012; sztanó et al., 2013). such an age significantly predates the pontian interval, which is constrained in the northern black sea basin to 6.04– 5.60 ma (krijgsman et al., 2010). to avoid the pitfalls of erroneous correlations in the future and to stabilize the regional chronostratigraphic sche mes, the usage of units defined outside the respective geodynamic complex should be rejected. yet, the third depositional megacycle of the sava depression (figure 3), marked by the deposition of figure 3: revised regional stratigraphic scheme of the sava ba­ sin (modified after saftić et al., 2003). those authors place the synrift/postrift boundary at the transition of the middle to late miocene. yet, in the eastern sava depression this boundary cor­ relates with the middle badenian as documented by pavelić (2001). matencu & radivojević (2012) demonstrated that the synrift phase continues in some regions of the southern panno­ nian basin well into the pannonian, whereas the postift phase may start already in the early badenian. 3) shows three depositional megacycles separated by compressional phases dated to the late middle miocene, the miocene-pliocene transition and the early pleistocene (saftić et al., 2003). the first cycle comprises up to 2 km of middle miocene marine deposits of the central paratethys, the second cycle represents up to 2.5 km of upper miocene brackish water deposits of lake pannon, and the third cycle includes up to 0.9 m of freshwater deposits of the pliocene lake slavonia (ožegović, 1944; saftić et al., 2003). pleistocene to holocene alluvial, marsh and aeolian deposits seal the succession. 3. revision of the stratigraphic nomenclature and the new regional stage cernikian in terms of regional stratigraphic nomenclature, the complete second megacycle of the sava depression infill corresponds to the pannonian stage (figure 3). its lower boundary corresponds to the formation of lake pannon, coinciding with the major extinction of sarmatian marine species (sarmatian–pannonian extinction event of harzhauser & piller, 2007). its upper boundary is defined by the formageologia croatica 68/3geologia croatica 182 the viviparus beds during the pliocene and pleistocene, has also been correlated with the dacian and/or romanian regional stages of the dacian basin (jenko, 1944; lučić et al., 2001; popov et al., 2004; malvić, 2012). however, due to tectonic inversion, lake slavonia represents a fully independent palaeogeographic unit from the early pliocene, showing depositional dynamics different to those of the dacian basin (saftić et al., 2003; sztanó et al., 2013; stoica et al., 2013; van baak et al., 2015). considering the enormous thickness of the viviparus beds along with their well-established stratigraphic subdivision (e.g., penecke, 1884; jenko, 1944; ožegović, 1944; takšić, 1954), and following the example from the dacian basin (andreescu & papaianopol, 1975; andreescu, 1975; papaianopol et al., 2003), we recognize a practical need for the introduction of a new and independent chronostratigraphic unit. thus, we herewith introduce the cernikian new regional stage (figure 2). the stage name derives from the village of cernik near the boundary stratotype, as defined below (figure 1 and 3). the stratigraphic content of the new regional stage corresponds to the viviparus beds as defined by neumayr & paul (1875). its duration equals their maximum depositional extent, i.e., it corresponds to the duration of lake slavonia. the stage is threefold as defined by its fossil content. hence, the lower cernikian or lower viviparus beds include the v. neumayri and v. kochanskyae zones; the middle cernikian or middle viviparus beds comprise the v. bifarcinatus, v. stricturatus and v. nothus zones; and the upper cernikian or upper viviparus beds include the v. sturi, v. hoernesi, v. zelebori and v. vukotinovici zones. the section ne of cernik (figure 1) is composed of marly clay with lignite seams bearing v. neumayri. it is superposed on the topmost pannonian sand and is proposed as the boundary stratotype for the cernikian (neumayr & paul, 1875, p. 9, fig. 4). the most complete succession occurring in the valley n of malino (figure 1) including lower, middle and upper viviparus beds, described in detail in neumayr & paul (1875, p. 10-11, fig. 6), represents the type section (“holostratotype”). a highly instructive, artificially outcropped section, showing a complete development of the viviparus beds is described by ožegović (1944) from the gojlo anticline (figure 1) e of kutina in ne croatia (“faciostratotype”). there, the 900-m-thick cernikian interval is composed largely of greenish clay and fine-sand with abundant viviparids. the 200-m-thick lower cernikian and the 600-m-thick upper cernikian interval contain 0.1 to 2-m-thick coal seams. 4. vukomeričke gorice horst-anticline the investigated samples are from a 12 km² area large, 7.8 km long, and nw-se striking region around kravarsko. this village and municipality is located 30 km s of zagreb in croatia (figure 1). the region is located on the ne flank of slightly elevated, forested countryside termed vukomeričke gorice, representing a large-scale horst-anticline composed of several smaller anticlines, uplifted in the pleistocene along parallel longitudinal faults (pikija, 1987a). its surface is composed of the viviparus beds, which are partly overlain by periglacial deposits at the northeastern margin (pikija, 1987b). the basement, detected in wells at a depth of 863 m (well dubranec 2; galović, 1952), consists of palaeozoic green quartz-chlorite schists and belongs to the internal dinaride jadar-kopaonik thrust sheet (schmid et al., 2008). it is directly overlain by badenian biogene limestones. upwards, the succession comprises sarmatian marls and sandstones, pannonian marls and cernikian clays (figure 3). the cernikian interval attains thicknesses of 200 to 450 m with inclinations of 2° to 12°. in the kravarsko area, the middle cernikian was not discovered either by drilling or surface mapping (galović, 1952; gagić & sokač, 1970; jurković, 1993). the lower cernikian, is represented here only by the v. kochanskyae zone, and is dominated by plastic clay, bearing some sand packages and up to 3.8 m thick coal seams consisting of reedand wood-like plant material (stur, 1863; farkaš-vukotinović, 1863; jurković, 1993; šebečić, 2010). above an indistinct unconformity, the upper cernikian shows an erosional contact with some faunal reworking. sandy clays alternate and there are few lignite seams, and local coarse to fine grained gravel packages. the v. sturi, v. hoernesi and v. vukotinovici zones were detected in the upper cernikian. the initial work on the mollusc fauna of the vukomeričke gorice hills was carried out by pilar (1873) and brusina (1874a, b, 1884, 1885, 1896, 1897, 1902). koch (1917) provided the last census of the fauna recording 41 species altogether, although his list lacked the middle cernikian zonal markers. gagić & sokač (1970) studied the ostracods from the drill cores. the faunal composition suggested a vegetated lake bottom in shallow sublittoral water-depths of 10 m or less, and a pliocene to pleistocene age for the cernikian deposits. 5. localities and samples from each locality one sample was analyzed, coded as krai, vgk-39, vgk-38 and vgk-35 (figure 1). kra-i is located 1.73 km nw of the holy cross church in kravarsko, sw of the houses termed povoljnaki, at 192 m a.s.l., on the slope below the main road (45.595525°n 16.038053°e). the outcrop area is an active landslide laterally extending about 50 m. except for a 3.4 m thick interval exposed at the northern limit of the landslide area, the bedding is largely disturbed. the former outcrop is dominated by a structure-less, grayish to yellowish clayey silt, with scattered plant remains. a 1.15 m thick unit of gray homogenous clay is intercalated in the lower part of the interval. the topmost 25% of this package displays fine-scale banding due to the intercalation of fine and medium grained sand. the sampled mollusc concentration occurs in the land-slide area, laterally to the outcrop, being strongly deformed and disjointed. it acted apparently as an inhomogeneity surface with the original stratigraphic position on top of the undisturbed interval (figure 4). vgk-39 is located within kravarsko, 330 m nw of the holy cross church, at 215 m a.s.l. on the same slope as the mandic et al.: stratigraphic and palaeogeographic significance of lacustrine molluscs from the pliocene viviparus beds in central croatia geologia croatica 183 previous locality, 80 m w of the road junction (45.588015°n 16.044973°e). this locality has no exposed section. the sample was taken from a shell accumulation entirely disturbed by the land-slide very similar to kra-i. vgk-38 is located 3 km ne of donji hruševac, 7.3 km se of the previous sample point, in the veliki burdelj wood, 230 m nw of the path to brenčići, in the trench of the ne flowing ephemeral stream at 152 m a.s.l. (45.551984°n 16.084993°e). the collected gastropod shell originated from debris accumulated by the stream. the shells derive from an unknown position within the cernikian deposits exposed along the trench in upstream direction. the distance to the stream head of only 260 m makes longer transport improbable. vgk-35 is located 2.7 km wsw of vgk-39, beside the path in the wood sws of novo brdo at 165 m a.s.l. (45.582877°n 16.021478°e). the small outcrop exposes 1.6 m of yellowish macrofossil free sand in its lower part. a 0.8 m thick fining upward interval of sandy to clayey silt follows (with an erosive boundary) in the upper part of the section. the sample comes from the initial 10 cm of the latter interval bearing poorly preserved, non-oriented mollusc shells suspended in a sandy silt matrix (figure 4). 6. results and discussion 6.1. taxonomy, palaeoecology and stratigraphy the taxonomic revision provides several updates for the fauna (table 1). vi­ viparus kochanskyae is introduced as a new species for the zonal marker of the lower cernikian, a taxon formerly identified as viviparus fuchsi (neumayr, 1872), which, however, is restricted to the pannonian basin. three species, microcolpia friedeli, prosost­ henia? slavonica and potomida seljani are newly combined in agreement with modern systematics (see taxonomy below). the cross-checking of the literature allowed a precise stratigraphic and palaeo biogeographic evaluation of the record (tables 2 to 3). except for litho­ glyphus decipiens, bithynia vukoti­ novici and theodoxus semiplicatus, all other taxa are approved and appear to be restricted to lake slavonia (table 3). altogether, the samples contain 13 lacustrine species, comprising 2 bivalve and 11 gastropod species (table 1). as expected for the viviparus beds, viviparids are the most diverse (4 species), followed by melanopsids and hydrobiids (2 species each). further families (valvatids, nertable 1: species identified in the studied samples. the previously unknown species from central croatia are marked by asterisks. class family species kr a­ i vg k­ 39 vg k­ 38 vg k­ 35               gastropoda valvatidae valvata subcarinata x x neritidae theodoxus semiplicatus x x viviparidae viviparus kochanskyae n. sp. x x viviparus hoernesi x viviparus aulacophorus* x viviparus dezmanianus x melanopsidae melanopsis clavigera* x microcolpia friedeli x x bythiniidae bythinia vukotinovici x x hydrobiidae prososthenia? slavonica* x lithoglyphus decipiens* x x bivalvia sphaeridae pisidium solitarium* x   unionidae potomida seljani   x     figure 4: the studied sections. arrow marks the mollusc sample. geologia croatica 68/3geologia croatica 184 table 2: stratigraphic distribution of the identified taxa in the revised lake slavonia chrono­ and biostratigraphic scheme. integrating results by neu­ mayr & paul (1875) and penecke (1884), the lake slavonia viviparid gastropod zones are defined here by the first appearance of the name­giving tax­ on. except for v. neumayri and v. stricturatus, all are confined to their respective zones. horizons identified in the studied region are marked in bold. substage lineage zone viviparus va lv at a su bc ar in at a th eo do xu s s em ip lic at us vi vi pa ru s k oc ha ns ky ae n . s p. vi vi pa ru s h oe rn es i vi vi pa ru s a ul ac op ho ru s vi vi pa ru s d ez m an ia nu s m el an op sis cl av ig er a m ic ro co lp ia fr ie de li by th in ia v uk ot in ov ic i pr os os th en ia ? s la vo ni ca li th og ly ph us d ec ip ie ns pi sid iu m so lit ar iu m po to m id a se lja ni upper cernikian vukotinovici ? x   x x zelebori ? x x   x x i hoernesi ? x x (x) x   i x i sturi   ? x       x     ? x x   i middle cernikian notha ? x x ? x x i stricturatus ? x x x x x i bifarcinatus   ? x             ? x x   i lower cernikian kochanskyae x x x x x x x x x x neumayri           x       ?   x     x: present study x: literature data ?: literature data on valvata piscinalis and bythinia tentaculata i: interpolated table 3: stratigraphic (epoch) and geographic (palaeolake or region) distribution of the species identified in the studied samples; x ­ present, (­) ­ absent (previously misidentified), ? ­ identification uncertain. species miocene pliocene pleistocene   br es se fr an kf ur t d in ar id es m et oh ia la ke p an no n la ke d ac ia bl ac k se a   m et oh ia br as ov n e cr oa tia la ke d ac ia bl ac k se a ae ge an   br es se ro m e pa nn on . b . bl ac k se a ae ge an valvata subcarinata (­) (­) (­) x (­) theodoxus semiplicatus (­) x x x (­) (­) viviparus kochanskyae n. sp. (­) (­) (­) (­) (­) x (­) (­) (­) (­) viviparus hoernesi x (­) viviparus aulacophorus x viviparus dezmanianus x (­) ? melanopsis clavigera x (­) (­) microcolpia friedeli (­) x (­) bythinia vukotinovici x x x x prososthenia? slavonica (­) (­) (­) x (­) (­) (­) lithoglyphus decipiens x x x x (­) (­) x x x (­) pisidium solitarium x potomida seljani                                         itids, bithyniids, unionids and sphaeriids) are represented by only one species each. the highest number of species (10) is recorded from vgk-39, and they are also the best preserved. material from sample kra-i exhibits limonite colouring and partial leaching and contains a smaller number of species (6), all present in the previous sample. the difference in composition is probably only a taphonomic feature. this is supported by the presence of v. kochanskyae in both samples, which is a zonal marker restricted to the upper part of the lower cernikian. mandic et al.: stratigraphic and palaeogeographic significance of lacustrine molluscs from the pliocene viviparus beds in central croatia geologia croatica 185 in sample vgk-39, the melanopsid microcolpia friedeli is the most frequent species, followed by the hydrobiid prososthenia? slavonica. melanopsids are generalists occurring in lakes and rivers, tolerating even slightly brackish conditions (glaubrecht, 1996; bandel, 2000). hydrobiids are present in different types of environments, and are usually well adapted to littoral mud flat settings (glöer, 2002; neubauer et al., 2013a, b). valvata piscinalis, which may represent an ecological counterpart of v. subcarinata, prefers freshand hard-water lake settings with a rich vegetation cover (økland, 1990). theodoxus danubialis, as a potential counterpart of t. semiplica­ tus, is most abundant in fluvial environments but is also found in lakes (jurišićpolšak, 1979; welter-schultes, 2012). bythinia is a generalist, living in stagnant and moderately running waters on detritus-rich substrates (glöer, 2002). viviparids are pure freshwater dwellers (welter-schultes, 2012). some european species prefer rivers, others settle in lakes. in lake geneva, they are highly abundant in the shallow, littoral zone (glöer, 2002). with respect to the ecological requirements of the mollusc species, from the dominantly muddy sediment and the lignites, a calm, littoral setting of a freshwater lake can be inferred for the samples, which is in agreement with previous ostracod data (gagić & sokač, 1970). due to the generally poor preservation, the sample from novo brdo (vgk-35) revealed only two species (table 1), both of which are absent in kravarsko. viviparus hoernesi is a zonal marker of the upper cernikian, melan­ opsis clavigera is restricted to the v. hoernesi and v. zele­ bori zones (penecke, 1884). this suggests a stratigraphic position within the middle upper cernikian. v. dezmani­ anus, identified as a single species from the burdelj wood (vgk-38), could be of the same age. it has a long stratigraphic range (penecke, 1884), concurring among others also with v. hoernesi. this is in agreement with the results of previous investigators reporting both viviparid species as constituents of the upper cernikian fauna of the vukomeričke gorice hills (galović, 1952; gagić & sokač, 1970). 6.2. calibration of the cernikian to the gts and the pliocene climate optimum although representing an isolated lake, at least temporary southward outflow from the pannonian basin existed according to papaianopol & marinescu (1995), allowing some species to migrate to the dacian basin (figure 5 and 6). this facilitates a rough calibration of the cernikian biostratigraphy to the dacian and romanian substages based on shared viviparus zonal markers (figure 6). this allows an indirect correlation to the geological time scale (gts) based on the magnetostratigraphic age model for the pliocene of the dacian basin of van baak et al. (2015). this model calibrates the upper dacian (parscovian) base to 4.5 ma, the figure 5: stratigraphic correlation of the lake slavo­ nia stratigraphic units with the dacian basin chrono­ stratigraphy after van baak et al. (2015). calibration of viviparus biozones is based mainly on lubenescu & lubenescu (2008) and own data (see text). stand­ ard chronostratigraphy follows hilgen et al. (2012). note the indicated position of the two stratigraphic levels identified in the studied sites and the one mil­ lion year gap between them. this agrees with previ­ ously published results showing the absence of mid­ dle viviparus beds in western lake slavonia. this implies a 1 myr long retreat of the lake slavonia east­ wards with subsequent short­term flooding during the pliocene climate optimum. geologia croatica 68/3geologia croatica 186 lower romanian (sienisian) base to 4.2 ma, the middle romanian (pelendavian) base to 3.6 ma and the upper romanian (valachian) base to 3.1 ma. the calibration presented in figure 5 is based on a literature review: lubenescu & lubenescu (2008) showed v. stricturatus and v. sturi to be restricted to the pelendavian of the dacian basin. andreescu et al. (2013) presented v. bifarcinatus as a zonal marker of the same substage. van baak et al. (2015) used the first appearance of v. stricturatus as a marker of the base of the pelendavian. lubenescu & lubenescu (2008) reported v. pilari and v. rudis as being restricted to the valachian. the latter species are restricted in the pannonian basin to the v. hoer­ nesi zone (penecke, 1884). the correlation of the cernikian base with the base of the parscovian follows papaianopol et al. (2003). according to the presented correlation, the cernikian spans the interval from 4.5 ma to 2.0 ma. the lower boundary of the middle cernikian is correlated to 4.2 ma, the base of the upper cernikian corresponds to 3.3 ma, approximately coinciding with the start of the pliocene climate optimum (pco). the period between 4.3 and 2.7 ma represents a general warm phase during the pliocene, culminating between 3.3 and 2.9 ma. at that time, polar temperatures increased by up to 10°c, the ice caps melted rapidly and global sea level was about 25 m higher than today (folland et al., 1990; raymo et al., 1996; fedorov et al., 2013; willeit et al., 2013). interestingly, the increase of shell sculpture in lineages of the lake slavonia viviparids paralells the warming trend during the pco (figure 6). thereafter, generally weaker sculptured species of the v. vukoti­ novici zone followed (neumayr & paul, 1875). 6.3. implications for the history of lake slavonia the biostratigraphic framework described above allows correlation of the studied sites with the lower and upper cernikian (figure 5). this fully agrees with previous results by galović (1952) and gagić & sokač (1970) confirming that the middle cernikian is missing in the vukomeričke gorice hills. considering that the area represents the westernmost extent of lake slavonia and in respect to the general eastward fluvial flow direction in the pannonian basin, important implications for the history of lake slavonia can be drawn. in particular, the distribution pattern in the mollusc assemblages proved that two main flooding events of lake slavonia occurred in the investigated area, correlating with the viviparus kochansyki zone and the viviparus hoernesi zone. the first flooding coincided with the start of relatively warm climate conditions in the region (figure 6). lake slavonia had already at c. 4.3 ma a distinctly larger surface than lake pannon in its final phase in the early pliocene at c. 4.5 ma (magyar et al., 1999) (figure 1). in contrast, the middle cernikian seems to represent a generally arid climate phase in the region, resulting in the retreat of lake slavonia from the vukomeričke gorice hills. the second ingression at c. 3.1 ma coincided with the pco (fedorov et al., 2013; willeit et al., 2013), followed apparently by the reestablishment of humid conditions and a further increase in the size of lake slavonia (figure 5). marinescu & papaianopol (1995) reconstructed lake slavonia rather as a system of lakes connected by rivers. such a scenario was certainly possible for the time of the middle cernikian arid spell reflected by a more than 1 ma long interruption of lacustrine deposition in the vukomeričke gorice hills. the renewed rise of the lake indicates that lake slavonia was not simply filled from the west to the east like the miocene lake pannon (magyar et al., 2013). instead, active subsidence in the southern pannonian basin provided accommodation space for terrestrial input and allowed the persistent existence of lacustrine conditions throughout the pliocene and the earliest pleistocene (saftić et al., 2003). previous authors (galović, 1952; gagić & sokač, 1970) indicated the presence of the zonal marker v. vukotinovici in the vukomeričke gorice hills with fod at ~2.5 ma. therefore, the tectonic inversion could not have started prior to that time. a connection to the dacian basin as suggested by marinescu & papaianopol (1995) is corroborated by the high similarities between the mollusc faunas. following the figure 6: palaeogeographic map of the pliocene after neubauer et al. (2015a) indicating lakes from where the species observed at the vukomeričke gorice hills were previously reported. note that most of these occurrences are proven to be erroneous after the present revision (see table 3). mandic et al.: stratigraphic and palaeogeographic significance of lacustrine molluscs from the pliocene viviparus beds in central croatia geologia croatica 187 synopsis of neubauer et al. (2015a), 50 of the 163 species (30.7%) recorded for lake slavonia are also known from lake dacia (figure 6). it is therefore likely that temporary one-way connections existed through outflow from the pannonian basin (marinescu & papaianopol, 1995). 7. conclusion the pliocene viviparus beds of the vukomeričke gorice hills in central croatia represent the topmost sequence-stratigraphic megacycle of the sava depression sedimentary infill. this interval represents an independent phase of the geodynamic evolution of the pannonian basin. for that reason, a new regional stage termed the cernikian is introduced here, defined by the depositional cycle comprising the viviparus beds. the cycle is linked to the development of a freshwater lake termed lake slavonia. its deposits transgressively overlie pannonian brackish-water deposits of lake pannon, previously referred to the pontian. the pontian stage, however, is clearly older and was defined in a completely different geodynamic area. therefore, regional stages such as the pontian, dacian and romanian should only be used in the respective type areas and must not be applied to the southern pannonian basin. the investigated mollusc fauna from the region of kravarsko, including 13 freshwater lacustrine species, is dominated by gastropods (11 species). the taxonomic update of the fauna resulted in several revisions. the widely used name viviparus fuchsi neumayr, 1872 refers to a distinct species from lake pannon. therefore, we introduce the new species viviparus kochanskyae n. sp. for specimens from lake slavonia previously identified with v. fuchsi. the former “viviparus fuchsi zone” is consequently re-named to the “viviparus kochanskyae zone”. hydrobia slavonica vit­ rella brusina, 1897, from the pannonian of grgeteg in syrmia is preoccupied by the sarmatian species hydrobia vitrella stefanescu, 1896. therefore, we introduce prososthenia? praeslavonica n. nom. three species are newly combined: microcolpia friedeli (brusina, 1885), potomida seljani (brusina, 1902) and prososthenia? sla­ vonica (brusina, 1874). the fauna shows an excellent match with the viviparus beds of ne croatia proving it as a fully integrated constituent of the long-lived lake slavonia. the biostratigraphy of lake slavonia is well established, based on the rapid endemic evolution of viviparid gastropods. two stratigraphic horizons detected in the studied sites support previous regional subdivisons. these are the lower cernikian viviparus kochanskyae zone and the upper cernikian viviparus hoer­ nesi zone. the lack of the middle cernikian in the vukomeričke gorice hills indicates strong alteration of the lacustrine depositional settings in the pliocene of the southern pannonian basin. considering that the subsidence was constant within the respective megacycle, the inferred pattern is best explained by the middle cernikian arid spell reflected by back-stepping of the lake. the timing of the latter event is enabled through several zonal markers calibrated to the geological time scale in the dacian basin, indicating where some species of lake slavonia migrated via rivers. accordingly, the early cernikian lacustrine transgression dates to c. 4.3 ma and the base of the late cernikian to c. 3.1 ma, proving a more than 1 ma long depositional hiatus for the region. interestingly, the second lacustrine transgression of lake slavonia is marked by the evolution of strongly sculptured viviparid shells and coincides exactly with the pliocene climate optimum. 8. systematic palaeontology gastropod systematics follows bouchet & rocroi (2005) and the worms database. systematics of the bivalves follows bouchet & rocroi (2010) and graf & cumming (2007, 2014). abbreviations: lvb – lower viviparus beds mvb – middle viviparus beds uvb – upper viviparus beds nhm – natural history museum gba – geological survey vienna, austria class gastropoda cuvier, 1795 subclass heterobranchia gray, 1840 superfamily valvatoidea gray, 1840 family valvatidae gray, 1840 genus valvata o. f. müller, 1774 type species: valvata cristata o.f. müller, 1774; recent, europe; type by monotypy. valvata subcarinata brusina, 1878 figures 7.1-4 1869 valvata piscinalis lamarck – neumayr, p. 378, pl. 13, fig. 11 [pars; non nerita piscinalis o. f. müller, 1774; non vienna basin occurrences]. 1874a valvata piscinalis müller – brusina, p. 88-89 [pars; non nerita piscinalis o. f. müller, 1774; non vienna basin occurrences]. 1874b valvata piscinalis müller – brusina, p. 71 [pars; non nerita piscinalis o. f. müller, 1774; non vienna basin occurrences]. 1875 valvata piscinalis müller – neumayr & paul, p. 78, pl. 9, fig. 18 [pars; non nerita piscinalis o. f. müller, 1774; non vienna basin occurrences]. *1878 valvata subcarinata, brusina – brusina, p. 352353. 1884 valvata piscinalis müller – penecke, p. 36 [pars; non nerita piscinalis o. f. müller, 1774; non vienna basin occurrences]. 1884 valvata subcarinata brus. – penecke, p. 36. 1884 valvata hörnesi nov. form. – penecke, p. 38, pl. 10, fig. 3. 1897 valvata subcarinata brus. – brusina, p. 25, pl. 13, figs. 32-39. geologia croatica 68/3geologia croatica 188 figure 7: pliocene lacustrine gastropods (valvatidae, neritidae and viviparidae) from the pliocene of the kravarsko re­ gion.1-4 – valvata subcarinata brusina, 1878; 1­2 – vgk­39 sample no. 36; 3­4 – kra­i sample no. 26. 5-10 – theodoxus semiplicatus (neumayr in herbich & neumayr, 1875); 5­6 – vgk­39 sample no. 34; 7­8 – vgk­39 sample no. 34; 9­10 – kra­i sample no. 25. 11-12 – viviparus aulacophorus brusina, 1874; vgk­39 sample no. 31.13 – viviparus dezmanianus brusina, 1874; 13 – vgk­38 sample no. 19. 14-17 – viviparus kochanskyae n. sp.; 14­15 – vgk­39 sample no. 37; 16­17 – kra­i sample no. 27.18-19 – viviparus hoernesi neumayr, 1869; 18­19 – vgk­35 sample no. 29. 1928 valvata (cincinna) subcarinata brusina – wenz, p. 2450 [pars; regarding only slavonian occurrences]. non 1932 valvata (cincinna) piscinalis subcarinata brus. – jekelius, p. 64, pl. 5, figs. 25-27. 1974 valvata (cincinna) subcarinata brusina – milan et al., p. 145. 2014 valvata subcarinata brusina, 1878 – haszprunar, p. 100. material: vgk-39 (3 specimens from sample no. 16, 3 specimens from sample no. 36, and 11 specimens from sample no. 40), and kra-i (3 specimens from sample no. 5, and 2 specimens from sample no. 26). dimensions: height x width – 4.2 x 4.7 mm (figs. 5.12); 4.4 x 4.7 mm (figs. 5.3-4). description: glossy, trochiform shell, slightly wider than high (w/h=0.92), with 4.5 rounded whorls rapidly and continuously increasing in diameter, delineated by deep sutures. last whorl attains 87% of total shell height. aperture is subcircular,weakly oblique, slightly angulated adapically at the contact with the last whorl. peristome is sharply edged. umbilicus narrow and deep. shell covered with fine, nonprojecting growth lines and fine axial undulations marking the growth stops. protoconch low trochiform, attaining little more than one whorl, showing fine spiral microsculpture typical for valvatids. remarks: valvata subcarinata brusina, 1878 was introduced as a replacement name for valvata piscinalis neumayr, 1869 non müller, 1774 [although erroneously indicated as “non lamarck”] (haszprunar, 2014). the indication of a “holotype” of v. subcarinata by milan et al. (1974) for a specimen illustrated by brusina (1897, pl. 13, figs. 32-34; coll. nhm zagreb inv. no. 2117-763/1) from čaplja is incorrect. the eleven specimens from sv. linart (= st. leonhardt, church nw cernik) studied by neumayr (1869) are syntypes and no holotype or lectotype exists at present. to settle this issue, we herewith designate the specimen illustrated by neumayr (1869, pl. 13, fig. 11; coll. gba inv. no. 1869/001/0069) as the lectotype. neumayr & paul (1875) assigned the locality to the lvb v. fuchsi [= kochanskyae] zone. mandic et al.: stratigraphic and palaeogeographic significance of lacustrine molluscs from the pliocene viviparus beds in central croatia geologia croatica 189 for a long time, this species was considered conspecific with specimens from the pannonian of moosbrunn in the vienna basin identified by hörnes (1856) as valvata piscinalis müller, 1774 (neumayr, 1869; brusina, 1874a,b; neumayr & paul, 1875). even after bru sina (1878) introduced v. subcarinata as a new species restricted to lake slavonia sediments, this error was carried forward by wenz (1928). papp (1953, pl. 5, fig. 2) was the first to recognize this mistake and related the distinctly older austrian occurrence with the pannonian species valvata obtusaeformis lörenthey, 1906 stating its different outline due to a much slower increase of the spire’s diameter. after bandel (2010), the latter species might be related to the valvatoid hydrobiid genus jekeliella bandel, 2010. the recent valvata piscinalis müller, 1774 differs in its lower spire, the wider umbilicus and the missing posterior notch at the aperture, which is well-developed in specimens from the type locality and the present material from kravarsko. brusina (1874a, b) mentioned “two to three” specimens out of 35 from kravarsko that develop a sharp median spiral keel, restricted to the early whorls. this is not developed in our material. though brusina (1897) illustrated just those keeled specimens as representatives of v. subcarinata, he still considered the more frequent nonkeeled morphotype as conspecific. we follow this approach and treat both morphologies as belonging to the same species. penecke (1884), in contrast, used a different concept of v. subcarinata for his material. he restricted it to the keeled morphotype found in the lvb at malino and čaplja. for the keeled specimens from the uvb at repušnica and čaplja, he introduced v. hoernesi as new species, which later was considered a juvenile specimen of v. subcarinata by brusina (1897). consequently, he continued to identify the non-keeled morphologies with the recent valvata piscinalis, claiming its presence in all stratigraphic horizons of lake slavonia. he erroneously synonymized v. sulekiana brusina, 1874 with v. piscinalis, which differs clearly in its strongly flattened spire. the stratigraphically older specimens from the late miocene metohia basin in kosovo, erroneously identified as v. subcarinata by milošević (1984), differ in a narrower spire and smaller aperture. specimens from the dacian of the braşov basin, referred to v. subcarinata by jekelius (1932), expose several weak to prominent spiral keels and thus represent a different species. distribution: restricted to the viviparus beds of central croatia (prvonožina), ne croatia (ciglenik, gromačnik, ma lino, novska, repušnica, bečic, sv. linart, sibinj, čaplja). the occurrence of the present species in the pliocene (?) of the marija gorica hills in nw croatia is based on a record of valvata cf. piscinalis in gorjanović-kramberger (1892). this record was treated by brusina (1902, pl. 13, fig. 34) as valvata sp., which was apparently overlooked by wenz (1926) who considered it as synonym of v. subcarinata. subclass neritimorpha golikov & starobogatov, 1975 order cycloneritimorpha frýda, 1998 superfamily neritoidea rafinesque, 1815 family neritidae rafinesque, 1815 genus theodoxus montfort, 1810 type species: theodoxus lutetianus montfort, 1810 (currently considered as a synonym of theodoxus fluviatilis (linnaeus, 1758)); recent, europe; type by original designation. theodoxus semiplicatus (neumayr in herbich & neumayr, 1875) figures 7.5-10 ? 1873 n.[eritina] danubialis, pfr. – pilar p. 112, 132, 176. 1874a neritina danubialis var. sagittifera – brusina, p. 91 [nomen nudum]. 1874b neritina danubialis var. sagittifera – brusina, p. 73 [nomen nudum]. ? 1874a neritina danubialis c. pfeiffer – brusina, p. 90 [non c. pfeiffer, 1828]. ? 1874b neritina danubialis c. pfeiffer – brusina, p. 72 [non c. pfeiffer, 1828]. *1875 neritina semiplicata sandb. – herbich & neumayr, p. 412-413 [pars; excl. synonyms]. 1875 neritina danubialis var. sagitiffera brus. – neumayr & paul, p. 35 [nomen nudum]. 1884 neritina sagittifera brusina – brusina, p. 89-90. 1884 theodoxus semiplicatus neumayr – brusina, p. 101-102. 1884 neritina semiplicata sandberger – penecke, p. 17, pl. 10, figs. 30-35. ? 1884 theodoxus danubialis c. pfeiffer – brusina, p. 100-101. 1896 neritina (theodoxus) semiplicata neumayr – stefanescu, p. 115-116, pl. 10, figs. 70-72. 1897 neritodonta sagittifera brus. – brusina, p. 26, pl. 14, figs. 23-24. 1902 neritodonta sagittifera brus. – brusina, pl. 15, figs. 39-40. 1902 theodoxus semiplicatus (neum.) – brusina, pl. 15, figs. 65-71. 1902 neritodonta sp. – brusina, pl. 15, figs. 59-61. ? 1902 theodoxus danubialis? (c. pfeiff.) – brusina, p. 15, figs. 50-52. 1929b theodoxus (calvertia) sagittiferus (brusina) – wenz, p. 2976. 1929b theodoxus (theodoxus) semiplicatus (neumayr) – wenz, p. 3005-3006. ? 1929b theodoxus (theodoxus) cf. danubialis (c. pfeiffer) – wenz, p. 2993-2994. 1932 theodoxus semiplicatus (neumayr) – jekelius, p. 56-58, pl. 1, figs. 1-60, pl. 2, figs. 1-65, pl. 3, figs. 1-50, pl. 23, figs. 1-14. geologia croatica 68/3geologia croatica 190 plicatus neumayr in herbich & neumayr, 1875, t. transversalis pfeiffer, 1828 and t. militaris neumayr, 1869. while this was not followed by brusina (1897, 1902) and wenz (1928), jurišić-polšak (1979) confirmed penecke’s classification in her revision of the neogene croatian neritids, detecting again only three species, although splitting them into eight subspecies. these are t. transversalis (incl. t. t. transversalis, t. t. amethystinus, t. t. slavonicus), t. semiplicatus (incl. t. s. semiplicatus, t. s. capillaceous), and t. militaris (t. m. militaris, t. m. decosta­ tus, t. m. oblongus). in the corresponding deposits of vukomeričke gorice hills she detected only t. danubialis and t. transversalis. t. militaris clearly differs from the present species by its axial ribs. t. transversalis (sensu jurišić-polšak, 1979) is characterized by transverse colour-bands which are absent in our material. t. semiplicatus is characterized by fine denticles on the callus pad, distinguishing it clearly from t. danubialis. a tooth beneath the muscle insertion can be absent or present in t. semiplicatus (jurišić-polšak, 1979). in our specimens it is completely absent, making them similar in this respect to t. danubialis. the fact that a faint dentation of the columellar pad can easily remain undetected, the previous t. danubialis records from the vukomeričke gorice hills by pilar (1873), brusina (1874a, b) and jurišić-polšak (1979) require closer inspection. jekelius (1932) provided an excellent description and illustrations of numerous specimens of t. semiplicatus from several localities of the dacian of the braşov basin. in contrast, the record from the pleistocene of se hungary by halaváts (1888), later referred to by wenz (1929b), has been revised by krolopp (1976b) as t. prevostianus (pfeiffer, 1828). the much older records from the maeotian of sw ukraine, sw moldavia, and romania by roshka (1973), gozhik & prysjazhnjuk (1978), gozhik & datsenko (2007), and stoica et al. (2007) are possibly based on erroneous identifications. the alleged occurrence in the “pliocene” of bresnica in serbia mentioned by jurišić-polšak (1979) is most likely based on “neritodonta sp.” of brusina (1902, pl. 15, figs. 53-55). the latter species was collected from lacustrine deposits at the bresnica brook near kragujevac, considered as langhian (middle miocene) in age (pavlović, 1931; jovanović, 2012). the species actually represents theodoxus brusinai (pavlović, 1931), differing from the present species in its more rounded outline. “neritina semi­ plicata” sensu hoernes (1877) from the late messinian (�agatay et al., 2006) or early pliocene (melinte-do-�agatay et al., 2006) or early pliocene (melinte-do-et al., 2006) or early pliocene (melinte-dobrinescu et al., 2009) mactra beds of i̇ntepe in nw turkey is a misidentification. theodoxus sp. from the miocene lake rein in styria is similar but lacks the crenulation (harz hauser et al., 2014). distribution: lvb to uvb of lake slavonia in central croatia (kravarsko – the present study); norteastern croatia (čaplja, cernik, kindrovo, sibinj, malino, gromačnik, cigle nik, duboki dol, repušnica, kovačevac), nw serbia (čerević) and w romania (giulvaz); dacian of the braşov ba1944 theodoxus (calvertia) sagittiferus (brusina) – jenko, p. 114. 1974 theodoxus (calvertia) sagittiferus (brusina) – milan et al., p. 110. 1979 theodoxus (theodoxus) semiplicatus semiplicatus (penecke) [sic] – jurišić-polšak, p. 27, pl. 9, figs. 5-8. ? 1979 theodoxus (theodoxus) danubialis (pfeiffer) – jurišić-polšak, p. 29, pl. 9, figs. 3-4. 2008 theodoxus (theodoxus) semiplicatus neumayr – lubenescu & lubenescu, p. 81, fig. 1.7-9. material: vgk-39 (3 specimens from sample no. 14, 9 specimens from samples no. 34), and kra-i (3 specimen from sample no. 4, and 4 specimens from samples no. 25). dimensions: height x width – 5.8 (first whorl broken) x 5.6 mm (figs. 5.5-6), 6.2 x 5.4 mm (figs. 5.7-8), 6.6 x 7.3 mm (figs. 5.9-10). description: solid shell, consisting of 2.75 whorls. spire consists of two flattened whorls (always eroded in the present material). depending on the shell’s growth angle, the spire may be distinct or be fully covered by the last whorl. last whorl increases strongly in diameter, producing an oval shape in outline. aperture is semicircular, slightly inclined toward the columella, with sharp lateral margin. callus pad is well demarcated, slightly concave, smooth, bearing very fine denticles at its adapertural edge. colouring is dominantly expressed by black, axial zig-zag and wavy bands. in a few specimens the bands are fused, so that only a few lunate spots remain white. remarks: t. semiplicatus neumayr in herbich & neumayr, 1875 from vârghiş and araci (dacian, braşov basin, w romania) was made available through a lapsus calami for t. semidentatus sandberger, 1875 (see footnote in herbich & neumayr, 1875, p. 413). the latter species had been introduced for a misidentified species from the middle miocene of ribarić in the drniš basin, se croatia. not realizing that the middle miocene species is distinct from the pliocene one, herbich & neumayr (1875) mentioned “t. semiplicatus” (instead of t. semidenta­ tus) also from the dacian of the braşov basin. as they explicitly referred the misspelled species name to a different specimen, both names are valid. brusina (1884) was the first to recognize that these two names refer to different species. although citing 57 syntypes from čaplja near podvinje in slavonia (ne croatia), brusina (1874a) did not provide any description or illustration of his new subspecies t. danubialis sagittiferus. this species-group name is therefore a nomen nudum, a fact first recognized by jurišić-polšak (1979). nevertheless, neumayr & paul (1875) also foun d it at čaplja, in beds belonging to the v. hoernesi zone, and accepted it as an available name. brusina (1884) elevated the name to the species rank and provided a morphological description and therefore made it available. penecke (1884) revised the neritid record of the central lake slavonia accepting only three species, i.e., t. semi­ mandic et al.: stratigraphic and palaeogeographic significance of lacustrine molluscs from the pliocene viviparus beds in central croatia geologia croatica 191 sin in central romania (e.g., araci (=arpatac), vârghiş) and of lake dacia (e.g., breasta) (penecke, 1884; jekelius, 1932; jurišić-polšak, 1979). subclass caenogastropoda cox, 1959 order architaenioglossa haller, 1890 superfamily viviparoidea gray, 1847 family viviparidae gray, 1847 subfamily viviparinae gray, 1847 genus viviparus montfort, 1810 type species: viviparus fluviorum montfort, 1810 (currently considered as a synonym of viviparus viviparus (linnaeus, 1758)); recent, northern eurasia, europe, ana tolia and northern america; type by original designation. viviparus aulacophorus brusina, 1874 figures 7.11-12 *1874a vivipara aulacophora brusina – brusina, p. 88, pl. 2, figs. 14-15. 1874b vivipara aulacophora brusina – brusina, p. 70, pl. 2, figs. 14-15. 1875 vivipara aulacophora brus. – neumayr & paul, p. 66. 1884 vivipara rudolphi nov. form. – penecke, p. 29, pl. 9, fig. 14. 1897 vivipara aulacophora brus. – brusina, p. 24, pl. 12, figs. 23-24. 1902 vivipara aulacophora brus. – brusina, pl. 12, fig. 7. 1928 viviparus aulacophorus (brusina) – wenz, p. 2293 [pars; excluding records of vivipara anthracophila = v. leiostracus]. 1974 viviparus aulacophorus brusina – milan et al., p. 148. material: vgk-39 (3 specimens from sample no. 10, and 3 specimens from sample no. 31). dimensions: height x width – 16.4 x 9.8 mm (figs. 5.11-12), 34.2 x 22.9 mm (specimen illustrated by brusina, 1902). description: slender shell, consisting of 5 convex whorls. shell width attains about 60% of total height; suture not very deep but distinct. last whorl attains 70% of total shell height. the junction between the whorls is irregular, slightly gaping. protoconch is eroded, apex is blunt. whorls increase more strongly in height than diameter, resulting in a drop-shaped shell outline. aperture is oval to slightly dropshaped, with a weak posterior notch. peristome is sharp; umbilicus is narrow and slit-like. shell surface is glossy, bearing numerous fine, weakly but irregularly undulated spiral grooves; crossed by growth lines they partially produce a fine reticulate pattern. remarks: when describing the species, brusina (1874a) had only a single specimen from cernik (sv. linart) n of nova gradiška at hand. the specimen, with a height of 30 mm and a width of 20 mm, represents a holotype by monotypy (iczn art. 73.1.2) and is stored in the nhm zagreb (inv. no. 3215-861; milan et al., 1974). following the detailed geological description of the area by neumayr & paul (1875), the deposits at the type locality may be ascribed to the v. neumayri zone. viviparus rudolphi penecke, 1884 from the v. ko­ chanskyae zone of malino was previously recognized by bru sina (1897) as a synonym of v. aulacophorus. wenz (1926) erroneously synonymized the nomen nudum “v. anthra cophilus” as given in neumayr & paul (1875) with v. aulacophorus. he apparently overlooked the correction note in neumayr & paul (1875, p. 106), where they clearly indicate it as an error pro v. leiostracus. following iczn art. 32.4 and 32.5, the name anthracophilus clearly represents an inadvertent error and is thus unavailable. the specimen given as “viviparus neumayri trans v. suessi” in neumayr & paul (1875, pl. 4, fig. 4) from the uvb of novska seems to show a very fine spiral sculpture too, but has a much lower spire. viviparus pauli brusina, 1874 and v. dautzenbergi brusina, 1902 are both larger than the present species and develop a much more prominent spiral sculpture (see also brusina, 1897). viviparus pauli has been listed from kravarsko by brusina (1874a, b) but could not be detected in the course of our investigation. distribution: restricted to the lvb of lake slavonia from kravarsko in the west via nova gradiška (cernik/sv. linart, rešetari/jukićev jarak) up to malino in the east (brusina, 1874a, b; neumayr & paul, 1875; penecke, 1884). it was previously unknown from kravarsko (koch, 1917). viviparus dezmanianus brusina, 1874 figure 7.13 1869 vivipara rudis nov. sp. – neumayr, p. 375, pl. 14, fig. 11 [pars; non fig. 5]. *1874a vivipara dežmaniana brusina – brusina, p. 81-82, pl. 2, figs. 7. 1874a [vivipara dežmaniana] var. complanata brus. – brusina, p. 81-82, pl. 2, fig. 6. 1874b vivipara dežmaniana brusina – brusina, p. 6465, pl. 2, figs. 7. 1874b [vivipara dežmaniana] var. complanata brus. – brusina, p. 64-65, pl. 2, fig. 6. 1875 vivipara dežmaniana brus. – neumayr & paul, p. 67, pl. 6, figs. 9-10, 16-18. 1884 vivipara dežmanniana [sic] brus. – penecke, p. 30. 1928 viviparus dežmanianus dežmanianus (brusina) – wenz, p. 2312-2314. 1974 vivipara dezmanianus (brusina) – milan et al., p. 146, 148. material: vgk-38 (1 specimen from sample no. 19). dimensions: height x width – 29.6 x 18.5 mm (fig. 5.13). geologia croatica 68/3geologia croatica 192 descriptions: solid shell, large, broadly drop-shaped, comprising 5.25 whorls; width attains about 65% of height. protoconch is not preserved. first three whorls are weakly convex and separated by shallow sutures, producing a point ed, conical apex. thereafter whorls expand more strongly in height than width, resulting in an overall dropshaped outline. from the third whorl onwards, whorls expose markedly stepped outlines with flanks sub-parallel to the axis, a narrow sutural ramp and incised, slightly gaping sutures. angulation between ramp and flank starts rounded, but becomes progressively more strongly angled and sharper. ramps dip by 30° to 60°. flanks are initially slightly convex and then straight, up to slightly concave on the last whorl; a central spiral furrow emerges on the last two whorls. a second angulation is present at the transition between whorl flank and base; it becomes visible only on the last two whorls. base of the last whorl is weakly convex. last whorl attains about 80% of the total shell height. aperture is fragmented, but obviously broadly drop-shaped, posteriorly slightly narrowed. peristome is sharp in its preserved columellar part. umbilicus is closed. growth lines are distinct, opisthocline. remarks: brusina (1874a) introduced this species including a specimen of the syntype series of v. rudis neumayr, 1869. it is not clear from the discussion whether he considered v. dezmanianus as a replacement name of neumayr’s specimen or simply wanted to include it in the new species. therefore, all specimens studied by brusina (1874a) and the single specimen from neumayr (1869) are syntypes of v. dezmanianus. the specification of a “holotype” by milan et al. (1974), referring to the specimen from kovačevac (coll. nhm zagreb inv. no. 4272-1912/1) that was illustrated in brusina (1874a, b), is incorrect. to settle this issue we designate the same specimen herewith as a lectotype. we follow neumayr & paul (1875) and wenz (1926) and consider v. complanatus brusina, 1874 as conspecific with v. dezmanianus. its type series comprises 127 specimens from čaplja. it attains only 75% of the height of the typical morphotype and the keels are less pronounced, resulting in rather straight-sided whorl flanks (as in our specimens). these minor variations are considered to be within the range of intraspecific variability. in their revision of the viviparids from the pliocene of the dacian basin, lubenescu & zazuleac (1985) rejected the presence of v. dezmanianus in lake dacia. they treated the identifications of cobălcescu (1883) and wenz (1942) as v. pseudo dezmanianus lubenescu & zazuleac, 1985, whereas the specimens from the sienisian by porumbaru (1881), fontannes (1887) and stefanescu (1896) were referred to v. dezmanianus dac­ icus lubenescu & zazuleac, 1985. as noticed by neubauer et al. (2014a), the latter taxon is a junior synonym of v. dezmanianus turbureensis fontannes, 1887. whether or not v. dezmanianus turbureensis is really related to v. dezmanianus needs a more detailed assessment of the type material. according to taboyakova (1964), the record of v. dezmanianus from the late pliocene to pleistocene of the rioni bay in georgia (e.g., wenz, 1926) actually represents viviparus nataliae mikhaylovskiy, 1913. the species is, however, still listed from that region by anistratenko & gozhik (1995). a more thorough taxonomic revision of those records is required to confirm or reject this claim. distribution: restricted to the mvb and uvb of ne croatia. this is its first record from central croatia. neumayr & paul (1875) restrict the species at sibinj, slobodnica, gromačnik, ciglenik, podvinje-čaplja trench, repušnica and novska to the v. stricturatus and v. nothus zones (as applicable). penecke (1884) in turn listed the species from the v. stricturatus to v. hoernesi zone at ci glenik, malino, sibinj and podvinje-čaplja trench. viviparus hoernesi neumayr, 1869 figures 7.18-19 *1869 vivipara hörnesi nov. sp. – neumayr, p. 376, pl. 14, fig. 14 [pars; non fig. 13]. 1874a vivipara hörnesi neumayr – brusina, p. 84-85. 1874b vivipara hörnesi neumayr – brusina, p. 67-68. 1875 vivipara hörnesi neum. nov. form. – neumayr & paul, p. 56-57, pl. 4, fig. 21. 1884 vivipara hörnesi neum. – penecke, p. 28. 1896 vivipara hörnesi neum. – brusina, p. 135. 1917 vivipara hörnesi neum. – koch, p. 12. 1928 viviparus hörnesi (neumayr) – wenz, p. 23262328. material: vgk-35 (2 specimens from sample no. 9, 1 specimen from sample no. 18, and 2 specimens from sample no. 29). dimensions: height x width (of fragmented specimen) – 17.0 x 13.3 mm (figs. 5.18-19). description: solid, glossy shell, conical, with 5 whorls, with the last whorl attaining about 80% of the total height. protoconch is not preserved. apex is blunt. on the second whorl a prominent angulation emerges, forming a straight, near horizontal subsutural ramp. angulation successively passes into a marked, sharp keel. a second sharp keel bearing irregular, elongated nodes emerge at the transition between whorl flank and base and are visible only on the last whorl. whorl flank between keels is regularly concave. below the lower keel, 2 weak and thin keels cover the base of the last whorl. base is straight. aperture is not preserved but apparently sub-oval; umbilicus is completely covered. remarks: the type series includes a large number of specimens from the bukovica valley n of novska (as are all the illustrated specimens), repušnica and gradiška. we designate herewith the specimen illustrated in neumayr (1869, pl. 14, fig. 14), stored in the collection of the gba (inv. no. 1869/001/0055), as the lectotype. the type stratum in bukovica belongs to the v. hoernesi zone, which the species is restricted to. mandic et al.: stratigraphic and palaeogeographic significance of lacustrine molluscs from the pliocene viviparus beds in central croatia geologia croatica 193 neumayr in neumayr & paul (1875) separated the specimen of neumayr (1869) illustrated on pl. 14, fig. 13 as the new species v. ornata, based on the absence of nodes on the keels. penecke (1884) stated that these two species rather form a morphological continuum and a distinction is possible only between extreme morphotypes, which we do not follow. wenz (1928) also lists the species from craiova in the dacian basin, which needs a careful re-examination. lubenescu & lubenescu (2008) did not list this species in their comparison between dacian and pannonian basin molluscs. distribution: restricted to the uvb of lake slavonia – central croatia (farkašić, hrastovica near petrinja, kravarsko), northeastern croatia (bečic, brestača, čaplja bei podvinje, bukovica, giglenik, gradiška, gromačnik, malino, novska, repušnica, and sibinj), northwestern serbia (novi sad – petrovaradin) (neumayr & paul, 1875; brusina, 1874a, b; penecke, 1884; koch, 1917; wenz, 1928). viviparus kochanskyae n. sp. figures 7.14-17 1869 vivipara concinna sow. – neumayr, p. 373, pl. 14, fig. 4 [non paludina concinna sowerby, 1812; non paludina concinna sensu hörnes, 1856]. 1873 vivipara fuchsi, neumayr – pilar, p. 110 [non vivipara fuchsi neumayr, 1872]. 1874a vivipara fuchsi neumayr – brusina, p. 75 [non vivipara fuchsi neumayr, 1872]. 1874b vivipara fuchsi neumayr – brusina, p. 59 [non vivipara fuchsi neumayr, 1872]. 1875 paludina loxostoma sandberger – sandberger, p. 691-692. 1875 vivipara fuchsi neumayr – neumayr & paul, p. 58, pl. 5, fig. 5 [non vivipara fuchsi neumayr, 1872]. 1884 vivipara fuchsi neum. – penecke, p. 29 [non vi­ vipara fuchsi neumayr, 1872]. 1917 vivipara fuchsi neum. – koch, p. 12 [non vivipara fuchsi neumayr, 1872]. 1928 viviparus fuchsi (neumayr) – wenz, p. 2318-2321 [non vivipara fuchsi neumayr, 1872; pars; regarding only slavonian occurrences]. material:vgk-39 (2 specimens from sample no. 17, 1 specimen from sample no. 20, 1 specimen from sample no. 37) and kra-i (3 specimens from sample no. 6, and 1 specimen from sample no. 27). etymology: in honour of the croatian palaeontologist vanda kochansky-devidé (1915-1990) for her contribution to neogene malacology. diagnosis: broadly ovoid, solid shell of moderate size comprising 4-5 whorls, which expand more rapidly in height than diameter, with flanks initially convex, then flattened on the last two whorls. type specimen: we designate the specimen illustrated by neumayr (1869) as the holotype (coll. nhm vienna inv. no. 1855/0035/0052). type locality nova gradiška [=cernik] was referred to lvb by neumayr & paul (1875). dimensions: height x width – 28.3 x 19.3 mm (largest specimen, last quarter of the last whorl is missing, vgk39 sample no. 20), 23.2 x 15.8 mm (fragmented, figs. 5.1415), height x width – 16.5 x 13.3 mm (fragmented, figs. 5.16-17). description: smooth, solid shell, broadly ovoid, with 4.75 whorls and narrow umbilicus. shell width attains about 70% of its height. protoconch not preserved in the present material. whorls expand rapidly in height and diameter, with the last one attaining c. 75-80% of total height. early whorls slightly convex, not stepped, separated by distinct but shallow suture. flanks of the last two whorls flattened, passing into marked convexity below. base is straight, inclined by about 45°. the latter is not fully preserved in our material; appears to be drop-shaped. fine growth lines cover the shell. remarks: the alleged presence of “viviparus fuchsi” in the viviparus beds of croatia traces back to a series of misidentifications and nomenclatural mistakes. it started with a misidentification of neumayr (1869), who mentioned “vivipara concinna” from nova gradiška in ne croatia, apparently referring to the identification and illustrations from hörnes (1856, p. 581, pl. 47, fig. 17). that author, however, had described a much older species from the middle pannonian of moosbrunn in the vienna basin. despite superficial similarities, the single slavonian specimen differs in the less stepped spire and the characteristically flattened whorl flanks passing into the marked convexity towards the base. beyond that, neither of these species is viviparus concinnus (sowerby, 1812), which is yet another species from the paleogene of southern england. recognizing this, neumayr (1872) introduced the new name viviparus fuchsi in a short note on the viviparus beds, yet explicitly referring it to “v. concinna hörnes non sow.”. despite his clear intention to introduce the name for the slavonian species, v. fuchsi is still a replacement name for hörnes’ misidentified specimens from moosbrunn and not for the slavonian species. obviously unaware of neumayr’s (1872) new name, sandberger (1875) introduced “paludina loxostoma” as replacement name for the species described by hörnes (1856). although sandberger (1875) also gives neumayr’s record from the viviparus beds in the synonymy list and mentions its occurrence in nova gradiška, it is entirely clear from the discussion that p. loxostoma was intended solely as a replacement for hörnes’ material. he even listed the record of viviparus fuchsi by brusina (1874a, b) in the synonymy list, but, for whatever reason, did not consider it a valid geologia croatica 68/3geologia croatica 194 name. paludina loxostoma sandberger, 1875 is therefore an objective junior synonym of viviparus fuchsi neumayr, 1872. it was later also considered synonymous by neumayr & paul (1875) and wenz (1928). based on illustrations of neumayr & paul (1875), papp (1953) was the first to recognize the differences between the pannonian and slavonian species, but wrongly concluded that v. fuchsi is restricted to the viviparus beds and v. loxos­ tomus is the correct name of the pannonian species. therefore, v. fuchsi was not mentioned from the pannonian basin by later authors (e.g., strausz, 1942; bartha, 1977; stevanović et al., 1990; harzhauser & binder, 2004). in summary, v. fuchsi neumayr, 1872 and v. loxos­ tomus (sandberger, 1875) refer to the same species from the late miocene of the pannonian basin, whereas the slavonian species, usually referred to as “viviparus fuchsi”, actually has no name. therefore, we introduce viviparus ko­ chanskyae as a new species. consequently, also the former “viviparus fuchsi zone” has to be re-named the “viviparus kochanskyae zone”. “viviparus fuchsi” from the late miocene lake bressevalence in se france originates from a misidentification by delafond & depéret (1893). the french specimens have well-rounded, convex whorls and correspond well to viviparus dresseli (tournouër, 1875), described from the surroundings of lyon, a species they give in the synonymy list of v. fuchsi. specimens of “viviparus fuchsi” identified from the akchagylian (late pliocene) of the syzran region in western samara/russia by pavlov (1925) and from the pontian of the danube delta region in se ukraine by gozhik (2002) and gozhik & datsenko (2007) have convex whorls instead of the typically flattened ones and represent other, yet undetermined species. viviparus kochanskyae seems to be absent in the dacian basin. it is not listed (as v. fuchsi) in the monograph on its viviparid snails by lubenescu & zazuleac (1985). the pontian record at ploieşti by wenz (1928) dates back to a list of pilide (1877), reproduced also by stefanescu (1897, p. 61). viviparus fuchsi identified by beregov (1940) from the maeotian and dacian of bulgaria was shown by lubenescu & zazuleac (1985) to represent v. incertus sensu macarovici, 1940. the latter species name was recently recognized to be a primary homonym of v. incertus fuchs, 1877 by neubauer et al. (2014a), who introduced v. wesselinghi as a replacement name. jekelius (1932) reported v. fuchsi species from dacian deposits of the galat brook near aita seacă and ebhát határ near hăghig in the braşov basin, but without providing any illustrations or description. this record still needs to be verified. the alleged lineage leading from viviparus fuchsi to v. leiostracus in the pliocene of kos as described by neumayr (1880a) is based on misidentifications of v. calverti (willmann, 1981, p. 151). the record of v. fuchsi from the plio-pleistocene of patras, greece, by oppenheim (1894, p. 820), who did not provide description or illustrations, needs re-examination. distribution: restricted to the lvb (w to e) of vukomeričke gorice s of zagreb / central croatia (prvonožina, dubranec, kravarsko), slavonia / ne croatia (repušnica w kutina, novska, cernik n nova gradiška, bečic, malino, sibinj, podvinje – čaplja n slavonski brod) and syrmia / nw serbia (čerević e novi sad) (brusina, 1874a, b; neu mayr & paul, 1875; penecke, 1884; koch, 1917; wenz, 1928). order unassigned superfamily cerithioidea fleming, 1822 family melanopsidae adams & adams, 1854 genus melanopsis férussac in férussac & férussac, 1807 type species: melania costata olivier, 1804; recent, eastern mediterranean and middle east; type by subsequent designation by gray (1847). melanopsis clavigera neumayr in neumayr & paul, 1875 figures 8.9-10 *1875 melanopsis clavigera neum. nov. form – neumayr & paul, p. 41, pl. 7, figs. 13-14. 1884 melanopsis clavigera neum. – penecke, p. 22. non 1890 melanopsis clavigera neumayr – oppenheim, p. 591. non 1891 melanopsis clavigera neumayr – oppenheim, p. 466, pl. 26, fig. 4. 1897 melanopsis clavigera neum. – brusina, p. 7, pl. 5, fig. 19. ? 1897 melanopsis clavigera cesticillus brus.n. for. – brusina, p. 7, pl. 5, fig. 20. ? 1902 melanopsis clavigera cesticillus brus. – brusina, pl. 6, fig. 41. 1929a melanopsis clavigera clavigera neumayr – wenz, p. 2694-2695 [pars; regarding only slavonian records]. ? 1929a melanopsis clavigera cesticillus brusina – wenz, p. 2695-2696. ? 1974 melanopsis clavigera cesticillus brusina – milan et al., p. 88. material: vgk-35 (3 specimens from sample no. 8, and 2 specimens from sample no. 28). dimensions: height x width (of fragmented specimen) – 20.8 x 10.1 mm (figs. 6.9-10). descriptions: solid shell with slender to bulky conical, coeloconoid to ovoid outline and up to 9 whorls. shell width attains about 50% of height. whorls are separated by narrow, irregular sutures. protoconch unknown. sculpture starts on the second teleoconch whorl, comprising about 8 slightly prosocline axial ribs, extending across entire whorl height. number of ribs is roughly constant throughout ontogeny – ribs increase constantly in strength and are more or less continuous on successive whorls. on the last whorls, the ribs bear weak nodes near the upper suture. nodes become successively stronger, mandic et al.: stratigraphic and palaeogeographic significance of lacustrine molluscs from the pliocene viviparus beds in central croatia geologia croatica 195 producing a markedly stepped shell outline for the last 3 whorls. rib portions above and below nodes are concave. on the last 2-3 whorls, nodes are laterally connected via weak, concave keels. on the last whorl, ribs bear an additional elongate axial convexity marking the angulation between whorl flank and the straight base. in one specimen, each rib bears two nodes; in two other specimens, no nodes are developed at all. the last whorl attains about two thirds of the total shell height. the aperture is slender, elongated and has a thickened callus pad; it lacks a columellar fold. peristome and siphonal canal are not fully preserved. fine growth lines are visible at the exterior surface of the shell. remarks: brusina (1897) introduced the new subspecies melanopsis clavigera cesticillus for a specimen from kozarica near novska, but did not provide a description or discussion. from the illustrations he provided, it seems he based the distinction on the absence of ribs and nodes on the last two whorls. a specimen of m. clavigera cesticillus from the same locality illustrated in brusina (1902) shows a prominent keel, bearing irregular, bulbous knobs. as we are currently not aware of any morphotype representing a morphological transition to the typical m. clavigera, a taxonomic separation appears reasonable. the record of melanopsis clavigera by oppenheim (1891) from the early pliocene of megara in greece is clearly a misidentification. the greek species is much more gracile and bears finer and sharper ribs with three rows of small nodes. due to its weak spiral keel it does not show the stepped figure 8: pliocene lacustrine gastro­ pods (melanopsidae, bithyniidae, hy­ drobiidae and lithoglyphidae) from the pliocene of the kravarsko region. 1-8 – microcolpia friedeli (brusina, 1885); 1­2 – vgk­39 sample no. 33; 3­4 – kra­i sample no. 23; 5­6 – vgk­39 sample no. 33; 7­8 – kra­i sample no. 24. 9-10 – melanopsis clavigera neu­ mayr in neumayr & paul, 1875; vgk­ 35 sample no. 28. 11-14 – bithynia vukotinovici (brusina, 1874); 11­12 – kra­i sample no. 21; 13­14 – vgk­39 sample no. 30. 15-16 – pro sosthenia? slavonica (brusina, 1874); vgk­39 sample no. 38. 17-20 – lithoglyphus decipiens brusina, 1885; 17­18 – vgk­ 39 sample no. 32; 19­20 – kra­i sample no. 22. morphology typical of melan­ opsis clavigera. it is also very like ly that the pleistocene record from stamná in w greece by op penheim (1890), which lacks an illustration, can be ruled out as being conspecific with the present species. distribution: pliocene uvb in ciglenik, gromačnik, gro ma čnik-sibinj road, ko vačevac e nova gradiška, slavon ski brod (čaplja and čaplja-podvinje trench). this is its first record fro m central croatia. geologia croatica 68/3geologia croatica 196 genus microcolpia bourguignat, 1884 type species: melanopsis acicularis férussac, 1823; re cent, europe; type by subse quent designation by coss mann (1909) [misspelt as “microcalpia”]. microcolpia friedeli (brusina, 1885) n. comb. figures 8.1-8 1869 melanopsis acicularis ferussac – neumayr, p. 370, pl. 13, fig. 6 [non melanopsis acicularis férussac, 1823]. 1874a melanopsis acicularis férussac – brusina, p. 37 [pars; only regarding locality kravarsko]. 1874b melanopsis acicularis férussac – brusina, p. 24 [pars; only regarding locality kravarsko]. 1875 ?melanopsis acicularis fer. – neumayr& paul, p. 48-49 [non melanopsis acicularis férussac, 1823]. *1885 melanopsis friedeli brus. – brusina, p. 160. 1896 melanopsis friedeli brus. – brusina, p. 120. 1897 melanopsis friedeli brus. – brusina, p. 8, pl. 6, figs. 5-8. 1917 melanopsis friedeli brusina – koch, p. 11. 1929a melanopsis friedeli brusina – wenz, p. 2725-2726. 1974 melanopsis friedeli brusina – milan et al., p. 91. non 2003 melanopsis friedeli brusina, 1897 – pană, p. 319, pl. 9, figs. 14-16. material: vgk-39 (3 specimens from sample no. 12, and 4 specimens from sample no. 33) and kra-i (3 specimens from sample no. 3, 3 specimens from sample no. 23, and 5 specimens from sample no. 24). dimension: height x width – 16.8 x 5.8 mm (figs. 6.34), 17.4 x 6.7 mm (figs. 6.7-8). description: glossy, slender shell, elongate, with up to 9 whorls, and width attaining about 58% of height. whorls are weakly convex to straight in cross-section; sutures are shallow; the resulting outline is almost perfectly conical. shell base is slightly concave. last whorl attains 55-60% of the total shell height. some specimens with convex whorls develop weak, slender, irregularly spaced, opisthocyrt ribs on the last 3-4 whorls, with the point of maximum convexity in the middle. ribs on the last whorl are sigmoidal, parallel with the growth lines. aperture is oval, with moderately thickened callus. colouring occasionally present as yellow to orange quadratic spots, arranged in a loose chequer-board like pattern. remarks: as already stated in brusina (1885), this species might be closely related to microcolpia acicularis (férussac, 1823), which is the type species of microcol­ pia bourguignat, 1884. the original description by brusina (1885) was a rectification of erroneous identifications of specimens from kravarsko and podvornica with m. acicularis by brusina (1874a, b). brusina (1897) provided an excellent illustration of one complete specimen from the viviparus beds of podvornica, which was designated as a neotype by milan et al. (1974) (coll. nhm zagreb inv. no. 2998-664). however, this designation is insufficient according to iczn art. 75.3. it is entirely unclear whether the original type material of brusina (1885) has been lost or was later illustrated by brusina (1897). therefore, no type exists at present. the exact geographic position of the podvornica locality is uncertain. milan et al. (1974) indicated it to be ese of kutina, while jurišić-polšak (1979) positioned it n of kravarsko. its actual position could not be verified from additional literature. the partly enormous intraspecific variation of microcol­ pia species has recently been demonstrated by morphometric analysis for a late pleistocene to holocene microcolpia species flock from the peţea thermal spring in romania (neubauer et al., 2014b). melanopsis astathmeta brusina, 1897 from the lvb of novska (=m. decollata sensu penecke, 1884 non stoliczka, 1862) is very similar to the non-ribbed morphotype of m. friedeli. it is slightly broader, has a larger last whorl and a more expanded aperture (cf. brusina, 1897). nevertheless, it is clearly a specimen of microcolpia. melanopsis sandbergeri neumayr, 1869 from the lvb (?) of repušnica has a bulkier last whorl and a distinct fasciole on the neck. m. recurrens neumayr in neumayr & paul, 1875 (= m. decollata sensu neumayr, 1869 non stoliczka, 1862) from repušnica differs in its slightly stepped whorls with deeper sutures. the identification of melanopsis cf. friedeli from the portaferrian (latest pannonian) of beočin (n serbia) by koch (1902) has not recently been confirmed (ste va nović et al., 1990) and remains doubtful. the record by pană (2003) from the sienisian of valea fântânei in the dacian basin is a misidentification. the illustrated specimens are shorter, have higher apical angles and more convex outlines. distribution: lake slavonia deposits in central croatia at podvornica, kravarsko and prvonožina; occurrences in the lvb of northern serbia (krivci/sremski karlovci) could not been approved and need careful re-examination. order littorinimorpha golikov & starobogatov, 1975 superfamily truncatelloidea gray, 1840 family bithyniidae gray, 1857 genus bithynia leach in abel, 1818 type species: helix tentaculata linnaeus, 1758; recent, europe; type by subsequent designation by her rmann sen (1846). bithynia vukotinovici brusina, 1874 figures 8.11-14 1873 b.[ythinia] vukotinovići, brus. – pilar, p. 109, 176 [nomen nudum]. *1874a bythinia vukotinovići brusina – brusina, p. 69, pl. 5, figs. 13-14 [erroneously as “vukotiuovići” in plate captions]. 1874b bythinia vukotinovići brusina – brusina, p. 5152, pl. 5, figs. 13-14 [erroneously as “vukotiuovići” in plate captions]. mandic et al.: stratigraphic and palaeogeographic significance of lacustrine molluscs from the pliocene viviparus beds in central croatia geologia croatica 197 ? 1875 bythinia tentaculata l. – neumayr & paul, p. 73 [non helix tentaculata linnaeus, 1758]. 1875 bythinia vukotinovići brus. – neumayr & paul, p. 17, 74. ? 1881 bythinia rumana, porumbaru – porumbaru, p. 38, pl. 9, figs. 5-5a. ? 1881 bythinia vukotinovici (brus.) – porumbaru, p. 37, pl. 9, figs. 4-4a. 1883 bythinia tentaculata linné – cobălcescu, p. 140, pl. 13, figs. 14a-b [non helix tentaculata linnaeus, 1758]. 1885 bythinia vukotinovići brus. – brusina, p. 162. ? 1884 bythinia tentaculata linné – penecke, p. 33 [non helix tentaculata linnaeus, 1758]. 1896 bythinia vucotinovici [sic] stefanescu p. 108, pl. 10, figs. 22-27. 1917 bythinia vukotinovići brus. – koch, p. 15. 1928 bulimus vukotinovici vukotinovici (brusina) – wenz, p. 2258-2259. 1932 bulimus vukotinovici (brusina) – krejci-graf & wenz, p. 110. 1942 bulimus (bulimus) vukotinovici (brusina) – wenz, p. 52, pl. 16, figs. 243-248. 1961 bythinia vucotinovici [sic] brus. – bogachev, p. 304, pl. 49, pl. 16-19. 1972 n. [eumayria] vukotinovici (brusina) – girotti, p. 126-127, figs. 14-15. 1974 bulimus (bulimus) vukotinovici (brusina) – milan et al., p. 64. 1997 bulimus (bulimus) vukotinovici (brusina) – papaianopol & popescu, p. 200, 205, pl. 5, fig. 10. non 2003 bulimus (bulimus) vukotinovici (brusina) 1874 – pană, 312-313, pl. 8, fig. 1. 2003 bulimus (bulimus) vukotinovici (brusina, 1874) – papaianopol & marinescu, p. 270-271, pl. 7, fig. 5. 2006 bulimus (bulimus) vukotinovici (brusina) – papaianopol, p. 80, pl. 1, figs. 6-8. 2007 bithynia vucotinovici [sic] brusina – gozhik & datsenko, p. 83, pl. 75, figs. 2-5, pl. 76, figs. 1-2. material: vgk-39 (3 specimens from sample no. 30) and kra-i (2 specimens from sample no. 1, and 1 specimen from sample no. 21). dimensions: height x width – 12.6 x 8 mm (figs. 5.1112), 13.3 x 7.6 mm (figs. 6.13-14). description: glossy, solid shell, broad conical, with width attaining about 60% of height, consisting of 5 convex to near straight-sided whorls. protoconch is not preserved; early whorls convex to angulated, separated by shallow sutures. last whorl height attains about 75% of total shell height; grows more strongly in an anterior direction in adult specimens, the point of maximum convexity of the whorls shifting downwards and producing a deeper suture. base is weakly convex to straight. aperture is oblique, ovoid, rounded anteriorly, and more or less pointed posteriorly. peristome slightly thickened, adjoined interiorly by a shallow furrow for the operculum. in lateral view, aperture is inclined to the axis with about 10°. umbilicus covered or narrowed, slit-like. shell is covered by opisthocline to slightly opisthocyrt growth lines, which sometimes become stronger and form small riblets. additionally, shell surface occasionally bears irregular spiral wrinkles. remarks: the syntype series of brusina (1874a) comprises shells from the pliocene of kravarsko (church) in central croatia and from podvinje (čaplja) in northeastern croatia. additionally, he had a few opercula from bečic as well, which he assigned to the present species. milan et al. (1974) erroneously considered the syntype illustrated by brusina (coll. nhm zagreb inv. no. 3852-1492/1) as the holotype, which according to iczn art. 74.5 does not classify as a valid lectotype designation. therefore, following the iczn formal provisions of art. 74.7, we designate this specimen, illustrated in brusina (1874a, pl. 5, figs. 13-14), as the lectotype. type locality is the slope beneath the church in kravarsko; the type stratum belongs to the lvb v. kochanskyae zone. the differences to b. tentaculata are the larger size and the shape of the whorls with maximum convexity in a more abapical position. pilar (1873) discovered the present species in the wood between dubranec and dragonošci together with theodoxus sagittiferus [= t. semiplicatus], viviparus­ fuchsi [= v. kochanskyae], and microcolpia friedeli (among others), which could imply the same stratigraphic position as for kravarsko. neumayr & paul (1875) observed n. vu­ kotinovici in the v. stricturatus zone of gromačnik in ne croatia and detected b. tentaculata in lvb (cernik, čaplja, gornji raić) and mpb (gromačnik). penecke (1884) only distinguished b. tentaculata in the pliocene of northeastern croatia, particularly in the čaplja trench (lvb, uvb), malino (lvb-uvb) and sibinj (mvb). interestingly, brusina (1885) doubted the presence of b. tentaculata in slavonia, but (in contrast to wenz, 1928) did not synonymize the respective identifications with b. vukotinovici. this is probably because the latter identifications were never documented by an illustration. a reinvestigation of the material from the pliocene of northeastern croatia is necessary to solve the species-level content of the bithyniidae there. from central croatia, koch (1917) reported only the presence of b. vukotinovici (prvonožina, dubranjec, and kravarsko) and considered b. tentac­ ulata to be absent there. porumbaru (1881) was the first who identified b. vukotinovici from the pliocene of creţeşti and podari in the dacian basin. from creţeşti he also described the new species bithynia rumana. his illustrations show quite bulky specimens indicating that neither identification represents b. vukotinovici. cobălcescu (1883) only recognized b. ten­ taculata from the coeval deposits of cârlig representing a quite slender phenotype. stefanescu (1896) subsequently discovered b. vukotinovici in the pelendavian of breasta and bucovăţ, illustrating slender specimens clearly resembling the lectotype. he synonymized b. rumana with b. vukotinovici, but did not include b. tentaculata of cobălcescu (1883). wenz (1928) was the first to synonymize the latter identification with b. vukotinovici, but still considered b. rumana as separate species. note that gigeologia croatica 68/3geologia croatica 198 rotti (1972) again synonymized the latter species with b. vukotinovici, which is followed herein. distribution: lake slavonia deposits of central croatia (lvb of kravarsko, lvb? of dubranec and prvonožina) and northeastern croatia (lvb? of podvinje/čaplja, mvb of gromačnik and other questionable localities as listed below); pelendavian deposits of the dacian basin in romania, sienisian to pelendavian equivalents (late kimmerian) of sw moldavia and of sw ukraine. wenz (1942) discovered it was restricted to the romanian (“levantin”) of the dacian basin and illustrated specimens from bucovăţ, valea seacă and valea budurească. papaianopol & popescu (1997) and papaianopol et al. (2003) considered b. vukotinovici to be a biostratigraphic marker of the pelendavian. finally, papaianopol & macaleţ (2006) confirmed the former stratigraphic range and illustrated additional specimens from greaca, podari, and călugăreni. the record from the sienisian of carriere rosia by pană (2003) is based on a misidentification. except for romania, the presence of b. vukotinovici in the lake dacia deposits was also listed from the “levantin” of giurgiuleşti in sw moldavia by macarovici (1940). beyond that, gozhik & datzenko (2007) documented it from the adjacent sw ukraine ranging there from the late pliocene (uppermost kimmerian) to the early pleistocene. in the pleistocene, the species concurs with b. tentaculata. its presence in the kuyalnikian of odessa was documented by bogachev (1961). its record from the pleistocene of the taman peninsula in sw russia by vassoevich (1928) was not accompanied by an illustration and cannot be approved. family hydrobiidae stimpson, 1865 genus prososthenia neumayr, 1869 type species: prososthenia schwartzi neumayr, 1869; middle miocene, croatia; type by subsequent designation by clessin (1880). remark: the present species closely resembles species from the pliocene of italy, which were treated as prososthe­ nia by schlickum (1972) and esu & girotti (1975). most probably, these species do not represent prososthenia, considering the morphological differences from its type species, which is smaller, bulkier and strongly sculptured. a revision of this group, however, is beyond the scope of the present study. prososthenia? slavonica (brusina, 1874) n. comb. figure 8.15-16 *1874a hydrobia slavonica brusina – brusina, p. 65, pl. 4, figs. 13-14. 1874b hydrobia slavonica brusina – brusina, p. 48, pl. 4, figs. 13-14. 1875 hydrobia slavonica brus. – neumayr & paul, p. 77. 1884 hydrobia slavonica brus. – penecke, p. 35. 1884 hydrobia tenuis nov. form. – penecke, p. 35, pl. 10, figs. 4a-c. non 1888 hydrobia slavonica, brusina – halaváts, p. 177-178, pl. 31, fig. 8. non 1889 hydrobia slavonica brus. – tuccimei, p. 120, pl. 2, fig. 13. non 1893 hydrobia slavonica – delafond & depéret, p. 130, 154, pl. 7, fig. 35, pl. 9, figs. 33-35. 1897 hydrobia? slavonica brus. – brusina, p. 19, pl. 9, figs. 22-23, 26-27. 1902 hydrobia? slavonica – brusina, pl. 9, figs. 1-2. non 1914 hydrobia slavonica, brus. – halaváts, p. 219. non 1922 hydrobia cf. slavonica – wenz, p. 42-43, 64, pl. 3, fig. 24. non 1925 hydrobia slavonica brusina – fischer & wenz, p. 225-226, pl. 7, figs. 1-6. 1926 hydrobia slavonica brusina – wenz, p. 1935-1936 [pars; excl. hungarian, romanian, german and italian occurrences]. non 1977 hydrobia slavonica brusina – schlickum & puisségur, p. 275, pl. 24, fig. 6. non 1978 hydrobia slavonica brusina – schlickum & puisségur, p. 5, pl. 1, fig. 7. material: vgk-39 (22 specimens from sample no. 38, 23 specimens from sample no. 41, and >30 specimens from sample p1). dimensions: height x width – 5.5 x 2.0 mm (largest specimen of sample 38, figs. 6.15-16): 3.4 x 1.9 mm (largest specimen of sample 41). description: glossy, slender drop-shaped shell, comprising up to 7 low convex whorls, and width attaining about 35% of shell height. shell outline is variable in width, including wider and slender morphologies. apex is slightly inflated, blunt, with highly convex initial two whorls. the following three whorls are weakly convex and form a regular conical outline; they are separated by distinct, moderately deep to shallow sutures. shell height increases faster than the diameter, producing the typically drop-shaped appearance. in later ontogeny whorl flanks are sub-parallel to the axis, weakly convex, often centrally flattened, with slightly deeper sutures than before. the last whorl forms about 55% of the total shell height, is globose with a slightly convex shell base. umbilicus is covered or very narrow. aperture is ovate to drop-shaped, oblique. posterior shell portion of the aperture is thickened and attached to the base of the preceding whorl. shell is covered with orthocline growth lines. a weak subsutural band is present in a few specimens. remarks: brusina (1874a, b) based this species on specimens from the localities of bečic, podvinje (čaplja) and sibinj in slavonia (ne croatia). we designate herewith the specimen from čaplja illustrated by brusina (1874a, pl. 4, figs. 13-14) and stored at the nhm zagreb (inv. no. 3051-697) as the lectotype. its previous reference as “holotype” in milan et al. (1974) does not constitute a valid lectotype designation (iczn art. 74.5). mandic et al.: stratigraphic and palaeogeographic significance of lacustrine molluscs from the pliocene viviparus beds in central croatia geologia croatica 199 penecke (1884) stated that the typical h. slavonica is absent in his samples from slavonia and separated shells with flattened whorls as the new species hydrobia tenuis. this feature is quite variable in populations of h. slavonica, which is why h. tenuis was considered synonymous with h. slavonica by brusina (1897) and wenz (1922). the illustrated specimen derives from the viviparus stricturatus zone of sibinj. hydrobia cf. slavonica sensu wenz (1922) and hyd­ robia slavonica sensu fischer & wenz (1925) from the late burdigalian “prososthenia beds” (= praunheim formation; kümmerle & radtke, 2012) of frankfurt am main and bommersheim in germany (see also wenz, 1926) superficially resemble the largest specimens from lake slavonia, but their spire is broader, the aperture is larger, whorls are convex and sutures are deeper. hydrobia slavonica sensu tuccimei (1889) from the plio-pleistocene of roccantica ne of rome is a misidentification, being distinctly smaller with a height of only 2.3 mm and having a relatively larger last whorl. it was not mentioned in the census of the plio-pleistocene mollusc fauna from central italy by esu & girotti (1975). hydrobia slavonica reported from the pleistocene of lake bresse is also based on erroneous identifications. the specimen from the lower pleistocene (mn 17 according to esu, 1999) of montagny-lès-beaune illustrated by schlickum & puisségur (1978) has a similar size but more convex whorls and deeper sutures. the same is true for specimens from le villard near domsure and bligny-sur-ouche illustrated by delafond & deperét (1893) and the single specimen reported by schlickum & puisségur (1977) from the middle pleistocene of saint-bernard. the misidentifications from the dacian of the braşov basin locality vârghiş (herbich & neumayr, 1875) and bodoş (= budus) (roth, 1881) also reported in wenz (1926) were synonymized by jekelius (1932) with his new species hydrobia barzaviae. its presence in the pleistocene viviparus boeckhi zone of szentes in se hungary reported by halaváts (1888, 1914) was revised by krolopp (1976a, p. 201). after krolopp (1976a), the hydrobia species therein actually represents a new, as yet undescribed species. brusina (1897) introduced hydrobia slavonica vitrella for specimens from the late portaferrian (late pontian) of grgeteg in syrmia (nw serbia). this name is a primary homonym of h. vitrella stefanescu, 1896, a sarmatian species from the transylvanian basin. therefore, we propose prososthenia? praeslavonica n. nom. as a replacement name for the serbian species.the syntype from grgeteg illustrated by brusina is missing in the collection of the nhm zagreb (milan et al., 1974); it may be stored in the coll. ste vano vić at the nhm belgrade (pers. comm. zoran marković, nhm belgrade). h. vitrella stefanescu, 1896 differs from brusina’s species in its larger last whorl. with a height of 3.1 mm p. praeslavonicais distinctly smaller than p. slavonica. while wenz (1926) synonymized it with p. sla­ vonica, stevanović (1951) treated it as an independent subspecies, which he also reported from sremski karlovci. because of the morphological and stratigraphical differences, we consider both taxa as separate species. p. praeslavonica is perhaps the phylogenetic ancestor of p. slavonica. the systematic position of both species within prososthenia is still questionable, given the highly elongate shell and the thin peristome (cf. brusina, 1897). unfortunately, we lack material for p. praeslavonica and do not know about the more diagnostic features such as protoconch sculpture of either specices, which is why a systematic revision would be based on weak ground and is therefore avoided here. distribution: it is restricted to lake slavonia deposits from kravarsko in the west to slavonski brod (bečic-ciglenik [= cigelnik], malino, sibinj, slobodnica, and čaplja) in the east. its presence is ascertained for the mvb (sibinj, malino, slobodnica) and the uvb (bečic). the corresponding horizon at čaplja remains unknown at present. its occurrences further to the east at bačko novo selo (ne serbia; mvb and uvb) given by krstić & knežević (2003) are questionable. its presence at kravarsko was previously unknown (koch, 1917). the stratigraphic position of the type stratum at čaplja was not specified by brusina (1874a). according to neumayr & paul (1875), this locality covers the viviparus­ fuchsi [= kochanskyae], v. hoernesi and v. zelebori zones. additionally, these authors list h. slavonica from the v. stric­ turatus zones at slobodnica and the v. sturi zone at bečic. malino and sibinj belong to the v. bifarcinatus zone (penecke, 1884). family lithoglyphidae tryon, 1866 genus lithoglyphus menke, 1830 type species: paludina fusca pfeiffer, 1828; recent, europe; type by monotypy. lithoglyphus decipiens brusina, 1885 figures 8.17-20 1869 lithoglyphus naticoides ferussac sp. – neumayr, p. 378, pl. 13, fig. 10 [non paludina naticoides c. pfeiffer, 1828]. 1874a lithoglyphus fuscus ziegler – brusina, p. 67-68 [non paludina fusca c. pfeiffer, 1828]. 1874b lithoglyphus fuscus ziegler – brusina, p. 49-50 [non paludina fusca c. pfeiffer, 1828]. 1875 lithoglyphus fuscus ziegler – neumayr & paul, p. 74-75 [non paludina fusca c. pfeiffer, 1828]. 1881 lithoglyphus fuscus, ziegler – porumbaru, p. 39, pl. 9, figs. 9, 9a [non paludina fusca c. pfeiffer, 1828]. 1883 lithoglyphus fuscus ziegler – cobălcescu, p. 143-145, pl. 14, figs. 1-8 [non paludina fusca c. pfeiffer, 1828]. 1884 lithoglyphus fuscus ziegler – penecke, p. 34 [non paludina fusca c. pfeiffer, 1828]. *1885 l.[ithoglyphus] decipiens brus. – brusina, p. 162. 1894 lithoglyphus kinkelini – brusina in engelhardt, p. 171 [not seen]. geologia croatica 68/3geologia croatica 200 1896 lithoglyphus neumayri brusina – stefanescu, p. 111-112, pl. 10, figs. 52-53, 57. 1897 lithoglyphus decipiens brus. – brusina, p. 23, pl. 12, figs. 8-11. 1902 lithoglyphus kinkelini brus. – brusina, pl. 11, figs. 59-61. 1928 lithoglyphus decipiens brusina – wenz, p. 22722276. 1932 lithoglyphus acutus decipiens brusina – krejcigraf & wenz, p. 114. 1940 lithoglyphus decipiens brusina – macarovici, p. 325-326, pl. 5, figs. 91-93. 1942 lithoglyphus acutus decipiens brusina – wenz, p. 48, pl. 15, figs. 200-205. 1973 lithoglyphus acutus decipiens brusina – roshka, p. 190-191, pl. 30-31, figs. 442-447. 1974 lithoglyphus acutus decipiens brusina – milan et al., p. 79. 1995 lithoglyphus decipiens brusina – papaianopol & marinescu, pl. 46, figs. 5-7. 2003 lithoglyphus acutus decipiens (brusina) – pană, p. 310, pl. 6, figs. 5-6. material: vgk-39 (3 specimens from sample no. 11, 3 specimens from sample no. 32, and 17 specimens from sample no. 39), and kra-i (1 specimen from sample no. 1, 3 specimens from sample no. 2, and 4 specimens from sample no. 22). dimensions: height x width – 5.55 x 4.5 mm (figs. 6.17-18), 7.5 x 5.75 mm (figs. 6.19-20). descriptions: small, solid, bulky shell with up to 4 whorls, and width attaining about 80% of shell height. apex is blunt. spire trochiform, stepped, with deep sutures, flattened, subhorizontal ramps and slightly convex flanks. blunt angulation present between ramps and flanks. last whorl large, attaining 83% of shell height, showing straightened, oblique shell base. aperture is ovatesemicircular, inclined by 45° toward axis. peristome thickened, slightly protruding anteriorly and posteriorly, forming a continuum with the callus pad. umbilicus covered by the latter. apertural plane pos teriorly inclined. dense opisthocline growth lines present on glossy exterior shell. remarks: neumayr (1869) identified his specimen from the lvb of cernik (sv. linart church; stur, 1862; neumayr & paul, 1875) erroneously with the recent lithoglyphus naticoides (pfeiffer, 1828), which has a distinctly lower spire and a bulkier last whorl. the specimen he illustrated on pl. 13, fig. 10 (height x width = 8.0 x 5.3 mm) is stored in the collection of the gba (inv. no. 1869/001/ 0068). brusina’s (1874a) specimens derive from a number of localities from the central part of lake slavonia as well as from vlaško kostanjevlje (= kostanjevec) in kravarsko and farkašić donated to him by lj. v. farkaš-vu ko tinović. he claimed these are somewhat smaller in size than those from ne croatia and identified them as recent l. fus­ cus pfeiffer, 1828, which was followed by neumayr & paul (1875). the introduction of l. decipiens brusina, 1885 was a text-note referring to all specimens from slavonia previously misidentified with l. fuscus. later, brusina (1897) provided synonymy to his new species and illustrated specimens from kovačevac and malino. the specimen from kovačevac (nhm zagreb inv. no. 3090-736) was erroneously referred to as the “holotype” by milan et al. (1974). according to penecke (1884), the sediments at kovačevac belong to the uvb v. zelebori zone. from the lvb of malino, neumayr in neumayr & paul (1875) described the new species l. histrio which he presumed to be an aberrant variation from l. fuscus sensu brusina. it differs from the present species in its elongated, ovoid morphology. l. kinkelini brusina, 1894 from the portaferrian of kurd (se hungary) – illustrated for the first time in brusina (1902) – was synonymized by wenz (1928) with l. decipiens. wenz (1928) also listed bithynia brusinai halaváts, 1903 from the latest pannonian of kötcse se balaton (hungary) as well as l. naticoides sensu halaváts (1888) from the v. boeckhi zone (pleistocene) of szentes in se hungary as synonyms of the present species. however, krolopp (1976b) approved halaváts’ original identification, pointing out that l. decipiens is absent in the pleistocene of se hungary. the presence of l. decipiens at kötcse was confirmed by müller & magyar (1992). stefanescu (1896) erroneously introduced litho­ glyphus neumayri as a new name for the specimens from slavonia and romania identified previously with l. fuscus, apparently unware of l. decipiens. he referred the authorship to brusina, mentioning the corresponding collection label seen at the nhm zagreb. moreover, he was apparently unaware of introducing a primary homonym of lithoglyphus neumayri sinzov, 1877. anyway, l. neumayri is an objective junior synonym of l. decipiens. distribution: the species occurs in numerous localities of lake slavonia, ranging from the lvb to the uvb (penecke, 1884) and lake dacia (see below). the oldest records are listed from the portaferrian (late pontian sensu ste vanović et al., 1990) of hungary (e.g., kötcse) and the late maeotian of sw ukraine (roshka, 1973). particularly the ukrainian record extends the stratigraphic and geographic range of the species enormously, which is why a careful revision of roshka’s material is required. in addition to numerous central lake slavonian occurrences (lvb to uvb), neumayr & paul (1875) referred two specimens from the upper portaferrian lake pannon deposits at grgeteg and sremski karlovci (both nw serbia) to this species. wenz (1942) documented specimens from the pyrgula eugeniae beds (late dacian; andreescu et al., 2013) of the area around iordăcheanu/plavia/valea urloii and the late romanian of valea seacă. he listed this species in the dacian basin from the middle pontian to the late romanian. papaianopol & marinescu (1995) illustrated specimens from the getian of moreni in the dacian basin and parscovian of tudor vladimirescu well at the moesian platform (both romania). papaianopol et al. (1995) cited it from two additional – getian and parscovian – localities. fimandic et al.: stratigraphic and palaeogeographic significance of lacustrine molluscs from the pliocene viviparus beds in central croatia geologia croatica 201 nally, pană (2003) illustrated specimens from the pelendavian (middle romanian) of plopşoru (olari) in the dacian basin. additional localities in romania, where this species was cited from but not more recently documented from, go back to wenz (1928; dacian and romanian), krejcigraf & wenz (1932; upper pontian, dacian, upper romanian), and papaianopol et al. (2003; late dacian and parscovian). records by wenz (1928) that could not be confirmed are from (1) the dacian of araci (=arpatac) in the braşov basin, not confirmed by jekelius (1932), (2) the upper? miocene from sarajevo (lukavica) based on “lithoglyphus cf. fuscus” in neumayr (1880b), an identification automatically related to l. decipiens by wenz (1928), although it has never been recorded from the dinarides (e.g., har zhauser & mandic, 2008), and (3) the pliocene of the area around orahovac (kosovo) based on “lithoglyphus fus­ cus” in pavlović (1903). all these occurrences are high ly dubious and have never been described or illustrated. macarovici (1940) illustrated specimens from the dacian of dmytrivka in sw ukraine belonging palaeogeographically to the easternmost part of lake dacia. in addition, he recorded this species from numerous other dacian localities in moldova as well as in the sw ukraine. class bivalvia linnaeus, 1758 superorder palaeoheterodonta newell, 1965 superfamily unionoidea rafinesque, 1820 family unionidae rafinesque, 1820 subfamily unioninae rafinesque, 1820 tribe anodontini rafinesque, 1820 genus potomida swainson, 1840 type species: mysca (potomida) corrugata swainson, 1840 (currently considered a junior synonym of poto­ mida littoralis (cuvier, 1798)); recent, europe and middle east; type by original designation. potomida seljani (brusina, 1902) n. comb. figure 9.1-4 *1902 unio seljani brus. – brusina, p. 9, pl. 25, figs. 7-8. 1958 unio seljani brusina – modell, p. 224, pl. 4, fig. 3. 1974 unio seljani brusina – milan et al., p. 55. 1981 unio (wenziella) seljani brusina 1902 – žagarsakač, p. 18, pl. 2, figs. 5, 6, pl. 3, fig. 10. material: vgk-39 (3 specimens from sample no. 15 and 2 specimens from sample no. 35). dimensions: height x length (fragment of the anterior shell) – 30.7 x 28.4 mm (figs. 7.3-4; 32 x 50 mm reconstructed). descriptions: shell thick, moderate in size and convexity, elongated with height (reconstructed) attaining about 65% of length. outline is inequilateral with inflated, prosogyrate umbo shifted anteriorly and projecting over the hinge line. anterior and ventral margins are rounded; posterior margin is not preserved, possibly sub-rectangular. transverse keel is present posterioventrally. shell wall is nacreous, lamellate, maximum of 4 mm thick. exterior surface bears coarse, irregularly undulated to zigzag-patterned concentric lirae in the first 8 mm of ontogeny. afterwards, the shell exterior is smooth, apart from projecting growth constrictions and very fine growth lines. hinge comprises one massive, trigonal pseudocardinal on the right valve, subdivided by vertical grooves, adjoined by two elongated, pseudocardinals on the left valve. anterior adductor scar is deep and rugose. remarks: the holotype by monotypy is one fragmented left valve from kravarsko (burdelj wood) with a missing posterior shell portion and centrally fragmented hinge (nhm figure 9: pliocene lacustrine bivalves (unio­ nidae and sphaeridae) from the pliocene of the kravarsko region. 1-2 – potomida seljani (brusina, 1902); 1­2 – vgk­39 sample no. 35; 3­4 – vgk­39 sample no. 35. 5-6 – pisidium solitarium neumayr, 1875; 5­6 – vgk­39 sam ple no. 13. geologia croatica 68/3geologia croatica 202 zagreb inv. no. 2846/493; height of 28.5 mm, length of 36.0 mm, convexity of 10.5 mm). originally made available by illustration, žagar-sakač (1981) provided a detailed description, recombining the species with the genus wenziella modell, 1958. the latter is a junior synonym of potomida swainson, 1840 after graf & cummings (2014). distribution: known only from the pliocene of kravarsko in central croatia. superorder heterodonta neumayr, 1883 order venerida gray, 1854 superfamily sphaerioidea deshayes, 1855 family sphaeriidae deshayes, 1855 subfamily pisidiinae gray, 1857 genus pisidium pfeiffer, 1821 type species: tellina amnica müller, 1774; recent, northern hemisphere; type by subsequent designation by gray (1847). pisidium solitarium neumayr in neumayr & paul, 1875 figure 9.5-6 *1875 pisidium solitarium neum. nov. form. – neumayr & paul, p. 26, pl. 8, fig. 35. 1884 p[isidium]. solitarium neum. – penecke, p. 16. 1897 pisidium solitarium neum. – brusina, p. 35, pl. 21, figs. 11-14. material: vgk-39 (3 specimens from sample no. 13, and 1 specimen from sample p1). dimensions: height x length – 6.5 x 7.6 mm (figs. 7.5-6). descriptions: shell ovoid, fragile, inequilateral, posterioventrally elongated with length attaining 85% of height, with umbo shifted posteriorly, and the anterior part strongly protruded. moderately convex, with convexity attaining 32% of total height, and with dorsally shifted point of maximum convexity. opisthogyrate umbo is slightly projecting over the hinge line. anterior margin strongly convex, other margins are weakly convex. exterior shell surface bears regular, projecting sharp-topped commarginal lirae interrupted by concave growth constrictions (two in specimen on figures 9.5-6). adductor scars are of similar medium size but of different shapes. the posterior one is subcircular, anterior one narrowly ovate inclined toward the umbo. pallial line is integripalliate. right hinge has elongated lateral teeth, two massive anteriorly and two slender posteriorly. cardinal teeth are much smaller but distinct, elongated, inclined, joined beneath the umbo, the posterior one longer than the anterior. remarks: holotype by monotypy is a single left valve (height x length = 12.9 x 10.2 mm) from the v. vukotinovici zone of novska illustrated by neumayr & paul (1875) on pl. 8, fig. 35 and stored in the gba (inv. no. 1875/002/ 0028). brusina (1897) illustrated for the first time a right valve and additionally a hinge detail of the left valve of the species from the type locality. pisidium slavonicum neumayr in neumayr & paul, 1875 exhibits a similar shell sculpture but is larger, stronger postero-ventrally elongated, with a less robust and weaker arched hinge. likewise, p. clessini neumayr in neumayr & paul, 1875 (mvb-uvb) has a comparable sculpture, but its hinge is not that robust and arched (e.g., brusina, 1897, pl. 21, figs. 22-26). the record of p. solitarium by capellini (1880) from the late miocene of italy is a misidentification and does not even match at the genus level, showing a completely different hinge type. note that pisidium solitarium sensu prime (1870) is a nomen nudum introduced in a synonymy list of “pisidium henslowianum, jenyns” (=pisidium henslowanum (sheppard, 1825)) and therefore no senior homonym. distribution: pliocene viviparus beds of northeastern (uvb of novska; neumayr & paul, 1875) and central croatia (lvb of kravarsko; this study). acknowledgment our thanks go to d. pavelić and v. anistratenko for the thorough reviews of the manuscript. this study contributes to the project “freshwater systems in the neogene and quaternary of europe: gastropod biodiversity, provinciality, and faunal gradients” financed by the austrian science fund (fwf project no. p25365-b25) and to the project “basic geological map of republic of croatia 1:50 000” financed by the ministry of science, education and sports of the republic of croatia (project no. 181-1811096-1093). references abel, c. (1818): narrative of a journey in the interior of china, and of a voyage to and from that country, in the years 1816 and 1817; containing an account of the most interesting transactions of lord amherst’s embassy to the court of pekin, and observations on the countries which it visited. illustrated by maps and other engravings.– longman, hurst, rees, orme and brown, london, xvi + 420 p. adams, h. & adams, a. (1853–1858): the genera of recent mollusca arranged according to their organizations.– van voorst, london, 2 vol. of text (661 p.), 1 vol. of plates. andreescu, i. (1975): romanian.– in: steininger, f.f. & nevesskaya, l.a. (eds.): stratotypes of mediterranean neogene stages, vol. 2. committee on mediterranean neogene stratigraphy / veda, bratislava, 131–138. andreescu, i., codrea, v., lubenescu, v., munteanu, t., petculescu, a., stiuca, e. & terzea, e. (2013): new developments in the upper pliocene-pleistocene stratigraphic units of the dacian basin (eastern paratethys), romania.– quatern. int., 284, 15–29. doi: 10.1016/j.quaint.2012.02.009 andreescu, i. & papaianopol, i. (1975): dacian.– in: steininger, f.f. & nevesskaya, l.a. (eds.): stratotypes of mediterranean neogene stages, vol. 2. committee on mediterranean neogene stratigraphy / veda, bratislava, 57–70. anistratenko, v.v. & gozhik, p.f. (1995): mollyuski semeystv neritidae, viviparidae, lithoglyphidae i pyrgulidae (gastropoda, pectinibranchia) iz kimmeriyskikh otlozheniy abkhazii.– vestnik zoologii, 1, 3–13. bandel, k. (2000): speciation among the melanopsidae (caenogastropoda). special emphasis to the melanopsidae of the pannonian lake at mandic et al.: stratigraphic and palaeogeographic significance of lacustrine molluscs from the pliocene viviparus beds in central croatia geologia croatica 203 pontian time (late miocene) and the pleistocene and recent of jordan. – mitt. geol.-paläont. inst. univ. hamburg, 84, 131–208. bandel, k. (2010): valvatiform gastropoda (heterostropha and caenogastropoda) from the paratethys basin compared to living relatives, with description of several new genera and species.– freiberger forschungshefte, c 536/18, 91–155. bartha, f. (1977): a balatonszentgyörgyi téglagyári fejtö felsőpannóniai rétegeinek molluszka faunája.– földtani közlöny, 107, 130–149. beregov, r. (1940): le pliocène du district du lom (études stratigraphiques et paléontologiques) [in bulgarian].– revue de la société géologique bulgare, 11, 347–395. bogachev, v.v. (1961): materialy k istorii presnovodnoi fauny evrazii.– izdatel'stvo akademii nauk ukrainski ssr, kiev, 403 p. bouchet, p. & rocroi, j.-p. (2005): classification and nomenclator of gastropod families. malacologia, 47/1-2, 1–397. bouchet, p. & rocroi, j.-p. (2010): nomenclator of bivalve families; with a classification of bivalve families by r. bieler, j.g. carter & e.v. coan.– malacologia, 52, 1–184. bourguignat, j.r. (1884): histoire des mélaniens du système européen.– ann. malacol., 2, 1–168. brusina, s. (1874a): fossile binnen-mollusken aus dalmatien, kroatien und slavonien nebst einem anhange.– actienbuchdruckerei, agram, 138 p. brusina, s. (1874b): prilozi paleontologiji hrvatskoj ili kopnene i slatkovodne terciarne iskopine dalmacije, hrvatske i slavonije.– rad jugoslavenske akademije znanosti i umjetnosti, 28, 1–109. brusina, s. (1878): molluscorum fossilium species novae et emendatae, in tellure tertiaria dalmatiae, croatiae et slavoniae inventae.– j. conchyliol., 26, 347–356. brusina, s. (1884): die neritodonta dalmatiens und slavoniens nebst allerlei malakologischen bemerkungen.– jb. dtsch. malakozool. ges., 11, 17–120. brusina, s. (1885): bemerkungen über rumänische paludinenschichten mit bezug auf prof. cobalcescus werk ‘studii geologice si palaeontologice asupra unor teramuri tertiare din unile parti ale romaniei’.– verh. geol. r.-a., 6, 157–163. brusina, s. (1896): neogenska zbirka iz ugarske, hrvatske, slavonije i dalmacije na budimpestanskoj izlozbi.– hrvatsko naravoslovno društvo, 9, 98–150. brusina, s. (1897): gragja za neogensku malakološku faunu dalmacije, hrvatske i slavonije uz neke vrste iz bosne i hercegovine i srbije.– djela jugoslavenske akademije znanosti i umjetnosti, 18, 1–43. brusina, s. (1902): iconographia molluscorum fossilium in tellure tertiario hungariae, croatiae, slavoniae, dalmatiae, bosniae, hercegovinae, serbiae et bulgariae inventorum. atlas.– officina soc. typographicae, agram, 30 pls. �agatay, m.n., görür, n., flecker, r., sakin�, m., tünoglu, c., ellam, r.m., krijgsman, w., vincent, s.j. & dikbas, a. (2006): paratethyan mediterranean connectivity in the sea of marmara region (nw turkey) during the messinian.– sed. geol., 188–189, 171–187. capellini, g. (1880): gli strati a congerie e la formazione gessoso-solfifera nella provincia di pisa e nei dintorni di livorno.– atti della reale accademia dei lincei, ann. 277, memorie, ser. 3, 5, 375–427. clessin, s. (1880): studien über die familie der paludinen.– malakozool. bl., n. f., 2, 161–196. cobălcescu, g. (1883): studii geologice şi paleontologice asupra unor tărâmuri terţiare din unele părţi ale româniei.– memoriile geologice ale scólei militare din iaşi, 1, 1–161. ćorić, s., pavelić, d., rögl, f., mandic, o., vrabac, s., avanić, r., jerković, l. & vranjković, a. (2009): revised middle mi-(2009): revised middle mi-revised middle miocene datum for initial marine flooding of north croatian basins (pannonian basin system, central paratethys).– geol. croat., 62/1, 31–43. cossmann, m. (1909): essais de paléoconchologie comparée. huitième livraison.– privately published, paris, 248 p. cox, l.r. (1960): thoughts on the classification of the gastropoda.– proc. malacol. soc. london, 33, 239–261. cuvier, g. (1795): second mémoire sur l’organisation et les rapports des animaux à sang blanc, dans lequel on traite de la structure des mollusques et de leur division en ordre, lu à la société d’histoire naturelle de paris, le 11 prairial an troisième.– magazin encyclopédique, ou journal des sciences, des lettres et des arts, 2, 433–449. cuvier, g. (1798): tableau élémentaire de l’histoire naturelle des animaux.– baudoin, paris, 710 p. delafond, f. & depéret, c. (1893): études des gítes minéraux de la france. les terrains tertiaires de la bresse et leurs gîtes de lignite et de minerais de fer.– imprimerie nationale, paris, 332 p. deshayes, g.p. (1838): description des coquilles fossiles recueillies en crimée par m. de verneuil, et observations générales à leur sujet.– mém. soc. géol. france, sér. 1, 3, 37–69. deshayes, g.p. (1855): catalogue of the conchifera or bivalve shells in the collection of the british museum. part 2, petricoladae (concluded); corbiculadae.– british museum, london, 217–292 p. engelhardt, h. (1894): flora aus den unteren paludinenschichten des caplagrabens bei podvin in der nähe von brood (slavonien).–abh. senckenberg. naturforsch. ges., 18/2, 169–207. esu, d. (1999): contribution to the knowledge of neogene climatic changes in western and central europe by means of non-marine molluscs.– in: agustí, j., rook, l. & andrews, p. (eds.): hominoid evolution and climatic changes in europe, 1. cambridge univ. press, cambridge, 328–354. esu, d. & girotti, o. (1975): la malacofauna continentale del plio-pleistocene dell’italia centrale. i. paleontologia.– geol. rom., 13, 203–294. farkaš-vukotinović, l.v. (1863): ueber das vorkommen der kohle in croatien.– jb. k. k. geol. r.-a., 13/4, 530–532. fedorov, a.v., brierley, c.m., lawrence, k.t., liu, z., dekans, p.s. & ravelo, a.c. (2013): patterns and mechanisms of early pliocene warmth.– nature, 496, 44–49. férussac, a.e.j.p.j.f.d‘a.d. (1812): sur des terreins d‘eau douce observés en divers lieux, et sur les fossiles terrestres et fluviatiles.– annales du muséum national d‘histoire naturelle, 19, 242–256. férussac, a.e.j.p.j.f.d‘a.d. (1823): monographie des espèces vivantes et fossiles du genre mélanopside, melanopsis, et observations géologiques à leur sujet.– mémoires de la société d’histoire naturelle de paris, 1, 132–164. férussac, j.b.l.d'a.d. & férussac, a.e.j.p.j.f.d'a.d. (1807): essai d'une méthode conchyliologique appliquée aux mollusques fluviatiles et terrestres d'après la considération de l'animal et de son test. nouvelle édition augmentée d'une synonymie des espèces les plus remarquables, d'une table de concordance systématique de celles qui ont été décrites par géoffroy, poiret et draparnaud, avec müller et linné, et terminée par un catalogue d'espèces observées en divers lieux de la france.– de-delance, paris, xvi + 142 p. fischer, k. & wenz, w. (1925): die prososthenienschichten von frankfurt a. m.-praunheim und ihre fauna.– arch. molluskenkd., 57, 222– 233. fleming, j. (1822): the philosophy of zoology, a general view of the structure, functions and classification of animals, 2.– constable & co., edinburgh, 618 p. folland, c.k., karl, t.r. & vinnikov, k. ya. (1990): observed climate variations and change.– in: houghton, j.t., jenkins, g.j. & ephraums, j.j. (eds.): climate change: the ipcc scientific assessment, intergovernmental panel on climate change (ipcc). cambridge university press, cambridge, 195–238. fontannes, f. (1887): contribution a la faune malacologique des terrains néogènes de la roumanie.– archives du musèum d‘histoire naturelle de lyon, 4, 321–365. frýda, j. (1998): higher classification of the palaeozoic gastropods inferred from their early shell ontogeny.– in: bieler, r. & mikkelsen, p.m. (eds.): 13th international malacological congress, abstracts. washing-washington, d.c., 108. fuchs, t. (1877): studien über die jüngeren tertiärbildungen griechenlands.– denkschr. kaiserl. akad. wiss., math.-naturwiss. cl., 37/2, 1–42. gagić, n. & sokač, a. (1970): fauna ostracoda paludinskih naslaga vukomeričkih gorica.– vii kongres geologa jugoslavije, 1, 131–149. galović, s. (1952): o rezultatima dubokog istražnog bušenja na strukturi dubranec.– nafta, 11, 360–362. gaudenyi, t., nenadić, d. jovanović, m. & bogićević, k. (2013): the stratigraphical importance of the viviparus boeckhi horizon of serbia.– quatern. int., 292, 101–112. geologia croatica 68/3geologia croatica 204 gaudenyi, t., nenadić, d., stejić, p., jovanović, m. & bogičević, k. (2015): the stratigraphy of the serbian pleistocene corbicula beds.– quatern. int., 357, 4–21. girotti, o. (1972): il genere neumayria stefani 1877 (gastropoda, prosobranchia).– geol. rom., 11, 115–136. glaubrecht, m. (1996): evolutionsökologie und systematik am beispiel von süßund brackwasserschnecken (mollusca: caenogastropoda: cerithioidea): ontogenese-strategien, paläontologische befunde und zoogeographie.– backhuys, leiden, 499 p. glöer, p. (2002): süßwassergastropoden nordund mitteleuropas. 2. auflage.– conchbooks, hackenheim, 327 p. golikov, a.n. & starobogatov, ya. i. (1975): systematics of prosobranch gastropods.– malacologia, 15, 185–232. gorjanović-kramberger, k (1892): das vorkommen der paludinenschichten in den maria-goricaer hügeln in croatien.– verh. k. k. geol.r.-a., 1892, 108–110. gozhik, p.f. (2002): pontychni presnovodni molyusky pivdnya ukrainy i moldovy.– privately published, kiev, 96 p. gozhik, p.f. & datsenko, l.n. (2007): presnovodnyye mollyuski pozdnego kaynozoya yuga vostochnoy yevropy. chast’ ii.–natsional’naya akademiya nauk ukrainy, institut geologicheskikh nauk, kiev, 253 p. gozhik, p.f. & prysjazhnjuk, v.a. (1978): presnovodnye i nazemnye molliuski miotsena pravoberezhnoi ukrainy.– ed. an ukdr ssr (nau-ed. an ukdr ssr (naukova dumka), kiev, 173 p. graf, d.l. & cummings, k.s. (2007): review of the systematics and global diversity of freshwater mussel species (bivalvia: unionoida).– j. moll. stud., 73, 291–314. graf, d.l. & cummings, k.s. (2014): the freshwater mussels (unionoida) of the world (and other less consequential bivalves), updated 15 november 2014. mussel project web site, http://www.musselproject.net/. gray, j.e. (1840): shells of molluscous animals.– in: anonymous (ed.): synopsis of the contents of the british museum. g. woodfall, london, 105–152. gray, j.e. (1847): a list of the genera of recent mollusca, their synonyms and types.– proc. zool. soc. london, 5, 129–219. gray, j.e. (1854): a revision of the arrangement of the families of bivalve shells (conchifera).– annals and magazine of natural history (series 2), 13/77, 408–418. gray, j.e. (1857): a manual of the land and fresh-water shells of the british islands, ed. w. turton.– longman, brown, green, longmans, and robert, london, i–xvi + 335 p. halaváts, g.v. (1903): die fauna der pontischen schichten in der umgebung des balatonsees.– resultate der wissenschaftlichen erforschung des balatonsees, 1/1, 1–80. halaváts, g.v. (1914): die bohrung in nagybecskerek.– mitt. jb. kgl. ung. geol. r.-a., 22/2, 187–222. halaváts, j. (1888): der artesische brunnen von szentes.– mitt. jb. kgl. ung. geol. r.-a, 8/6, 165–194. haller, b. (1892): die morphologie der prosobranchier.– morphologisches jahrbuch, 18/3, 451–543. harzhauser, m. & binder, h.(2004): pannonian molluscs from the classical sections richardhof and eichkogel in the vienna basin (austria, late miocene).– arch. molluskenkd., 133, 1–57. harzhauser, m. & mandic, o. (2008): neogene lake systems of central and south-eastern europe: faunal diversity, gradients and interrelations.– palaeogeogr. palaeoclimatol.palaeoecol., 260, 417–434. doi: 10.1016/j.palaeo.2007.12.013 harzhauser, m., neubauer, t.a., gross, m.& binder, h. (2014): the early middle miocene mollusc fauna of lake rein (eastern alps, austria).– palaeontogr. abt. a, 302/1-6, 1–71. harzhauser, m. & piller, w.e. (2007): benchmark data of a changing sea. – palaeogeography, palaeobiogeography and events in the central paratethys during the miocene.– palaeogeogr. palaeoclimatol. palaeoecol., 253, 8–31. haszprunar, g. (2014): a nomenclator of extant and fossil taxa of the valvatidae (gastropoda, ectobranchia).– zoo keys, 377, 1–172. doi: 10.3897/zookeys.377.6032 herbich, f. & neumayr, m. (1875): beiträge zur kenntnis fossiler binnenfaunen. vii. die süsswasserablagerungen im südöstlichen siebenbürgen.– jb. k. k. geol. r.-a., 25, 401–431. herrmannsen, a.n. (1846): indicis generum malacozoorum primordia. nomina subgenerum, generum, familiarum, tribuum, ordinum, classium; adjectis auctoribus, temporibus, locis systematicis atque literariis, etymis, synonymis. praetermittuntur cirripedia, tunicata et rhizopoda. vol. i.– fischer, cassellis, xxvii + 637 p. hilgen, f.j., lourens, l.j. & van dam, j.a. (2012): the neogene period.– in: gradstein, f.m., ogg, j.g., schmitz, m. & ogg, g. (eds.): a geologic time scale 2012. elsevier, amsterdam, 923–978. hoernes, r. (1877): ein beitrag zur kenntniss fossiler binnenfaunen. (süsswasserschichten unter den sarmatischen ablagerungen am marmarameere.).– sitzber. akad. wiss., math.-naturwiss. cl., 74, 7–34. hörnes, m. (1851-1856): die fossilen mollusken des tertiär-beckens von wien. i. univalven.– abh. k. k. geol. r.-a., 3, 1–736. hörnes, m. (1870): die fossilen mollusken des tertiär-beckens von wien. ii. bivalven.– abh. k. k. geol.r.-a., 4, 1–479. jekelius, e. (1932): die molluskenfauna der dazischen stufe des beckens von brasov.– memorille institutului geologic al romaniei, 2, 1–118. jenko, k. (1944): stratigrafski i tektonski snošaj pliocena južnog pobočja požeške gore i kasonje brda.– vjestnik hrvatskog državnog geoložkog zavoda i hrvatskog državnog geoložkog muzeja, 2/3, 89–159. jovanović, g. (2012): srpsko jezero.– narodni muzej kruševac / prirodnjački muzej beograd, kruševac, 59 p. jurišić-polšak, z. (1979): miocenske i pliocenske neritide u hrvatskoj.– palaeontologia jugoslavica, 22, 1–50. jurković, i. (1993): mineraline sirovine sisačkog područja.– rudarskogeološko-naftni zbornik, 5, 39–58. koch, a. (1902): neuere beiträge zu den geo.oaläontologischen verhältnissen de beocsiner cementmergels.– földtani közlöny, 32, 271–280, 167–322. koch, f. (1917): levantinska fauna vukomeričkih gorica.– glasnik hrvatskoga prirodoslovnoga društva, 29, 7–17. krejci-graf, k. & wenz, w. (1932): stratigraphie und paläontologie des obermiozäns und pliozäns der muntenia (rumänien).– z. dtsch. geol. ges., 83, 65–163. krijgsman, w., stoica, m., vasiliev, i. & popov, v.v. (2010): rise and fall of the paratethys sea during the messinian salinity crisis.– earth planet. sci. lett., 290, 183–191. krolopp, e. (1976a): alföldi fúrások zsigmondy-halaváts-féle mollusca anyagának revíziója. i. aszentesi artézikút-fúrás.– magyar állami földtani intézet évi jelentése, 1973, 195–218. krolopp, e. (1976b): alföldi mélyfúrások zsigmondy-halaváts-féle mollusca anyagának revíziója. ii. a hódmezővásárhelyi, szegedi, szarvasi és kecskeméti artézikút-fúrások.– magyar állami földtani intézet évi jelentése, 1974, 133–156. krstić, n. (2003): paludinian beds of voivodina.– in: papaianopol, i., marinescu, f., krstić, n. & macaleţ, r. (eds.): chronostratigraphie und neostratotypen. neogen der zentrale paratethys, bd. x, pl2. romanien. editura academiei române, bucuresti, 77–81. krstić, n. & knežević, s. (2003): succession of the fauna of the paludinian beds.– in: papaianopol, i., marinescu, f., krstić, n. & macaleţ, r. (eds.): chronostratigraphie und neostratotypen, bd. x, pl2. romanien. editura academiei române, bucuresti, 83–92. kümmerle, e. & radtke, g. (2012): die fossilien des tertiärmeeres im hanauer becken.– jahresberichte der wetterauischen gesellschaft für die gesamte naturkunde zu hanau, 162, 59–77. linnaeus, c. (1758): systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. editio decima, reformata. tomus 1.– laurentius salvius, holmiae, 824 p. lörenthey, i. (1906): beitrage zur fauna und stratigraphischen lage der pannonischen schichten in der umgebung des balatonsees.– resultate der wissenschaftlichen erforschung des balatonsees, bd. 1, teil 1. anhang 4, 1–216. lubenescu, v. & lubenescu, d. (2008): neogenul superior strate cu paludine din romania.– studii si cercetari de geologie, 51–53, 77–88. mandic et al.: stratigraphic and palaeogeographic significance of lacustrine molluscs from the pliocene viviparus beds in central croatia geologia croatica 205 lubenescu, v.& zazuleac, d. (1985): les viviparidés du néogène supérieur du bassin dacique.– mémoires l‘institut de géologie et de géophysique, 32, 77–136. lučić, d., saftić, b., krizmanić, k., prelogović, e., britvić, v., mesić, i. & tadej, j. (2001): the neogene evolution and hydrocarbon potential of the pannonian basin in croatia.– mar. petrol. geol., 18, 133–147. macarovici, n. (1940): recherches géologiques et paléontologiques dans la bessarabie méridionale (roumanie).– annales scientifiques de l‘université de jassy, 36/1, 177–422. magyar, i., geary, d.h. & müller, p. (1999): paleogeographic evolution of the late miocene lake pannon in central europe.– palaeogeogr. palaeoclimatol. palaeoecol., 147, 151–167. magyar, i. & geary, d.h. (2012): biostratigraphy in a late neogene caspian-type lacustrine basin: lake pannon, hungary.– in: baganz, o.w., bartov, y., bohacs, k. & nummedal, d. (eds): lacustrine sandstone reservoirs and hydrocarbon systems. aapg memoir, 95, 255–264. magyar, i., radivojevic, d., sztanó, o., synak, r., ujszászi, k. & pócsik, m. (2013): progradation of the paleo-danube shelf margin across the pannonian basin during the late miocene and early pliocene.– global planet. change, 103, 168–173. doi: 10.1016/j.glo-– global planet. change, 103, 168–173. doi: 10.1016/j.gloplacha.2012.06.007 malvić, t. (2012): review of miocene shallow marine and lacustrine depositional environments in northern croatia.– geol. quarterly, 56/3, 493– 504. mandic, o., de leeuw, a., bulić, j., kuiper, k., krijgsman, w. & jurišić-polšak, z. (2012): paleogeographic evolution of the southern pannonian basin: 40ar/ 39ar age constraints on the miocene continental series of northern croatia.– int. j. earth sci., 101/4, 1033– 1046. marinescu, f. & papaianopol, i. (eds)(1995): chronostratigraphie und neostratotypen, bd. ix, pl1. dacien.– editura academiei române, bucuresti, 530 p. matenco, l. & radivojević, d. (2013): on the formation and evolution of the pannonian basin: constraints derived from the structure of the junction area between the carpathians and dinarides.– tectonics, 31, 1944–9194. melinte-dobrinescu, m.c, suc, j.-p., clauzon, g., popescu, s.m., meyer, b., armijo, r., biltekin, d., �ağatay, n., ucarkus, g., jouannic, g., fauquette, s. & �akir, z. (2009): the messinian salinity crisis in the dardanelles region: chronostratigraphic constraints.– palaeogeogr. palaeoclimatol. palaeoecol., 278, 24–39. menke, c.t. (1828): synopsis methodica molluscorum generum omnium et specierum earum, quae in museo menkeano adservantur; cum synonymia critica et novarum specierum diagnosibus.– gelpke, pyrmonti, xii + 91 p. mikhaylovskiy, g.p. (1913): istoricheskaya geologiya: kurs, chitannyy studentam imperatorskogo yur’yevskogo universiteta. vyp.1.– tipografiya trenke i fyusno, st. petersburg, 356 p. milan, a., sakač, k. & žagar-sakač, a. (1974): katalog originala tipova vrsta pohranjenih u geološko-paleontološkom muzeju u zagrebu.– geološko-paleontološki muzej u zagrebu, zagreb, 186 p. milošević, v.m. (1984): prilog poznavanju fosilnih gastropoda iz familije valvatidae iz slatkovodnih sedimenata metohijske kotline (neogen).– glasnik prirodnjačkog muzeja, ser. a, 39, 167–184. modell, h. (1958): die tertiären najaden des ungarischen beckens.– ge-geol. jb., 75, 197–250. montfort, p.d.d. (1810): conchyliologie systématique et classification méthodique de coquilles; offrant leurs figures, leur arrangement générique, leurs descriptions caractéristiques, leurs noms; ainsi que leur synonymie en plusieurs langues. ouvrage destiné ŕ faciliter l‘étude des coquilles, ainsi que leur disposition dans les cabinets d‘histoire naturelle. coquilles univalves, non cloisonnées.2.– schoell, paris, 676 p. müller, o.f. (1773–1774): vermium terrestrium et fluviatilium historia, seu animalium infusoriorum, helminthicorum et testaceorum non marinorum succincta historia.– heineck & faber, havniae et lipsiae, xxxiii + 135, xxxvi + 214 p. müller, p., geary, d.h. & magyar, i. (1999): the endemic molluscs of the late miocene lake pannon: their origin, evolution, and familylevel taxonomy.– lethaia, 32, 47–60. müller, p. & magyar, i. (1992): a prosodacnomyák rétegtani jelentősége a kötcse környéki pannóniai s.l. üledékekben.– földtani közlöny, 122/1, 1–38. neubauer, t.a., georgopoulou, e., kroh, a., harzhauser, m., mandic, o. & esu, d. (2015b): synopsis of european neogene freshwater gastropod localities: updated stratigraphy and geography.– palaeontol. electron., 18.1.3t: 1–7. neubauer, t.a., harzhauser, m., georgopoulou, e., kroh, a. & mandic, o. (2015c): tectonics, climate, and the rise and demise of continental aquatic species richness hotspots.– proc. natl. acad. sci. usa, 112/37, 11478–11483. doi: 10.1073/pnas.1503992112 neubauer, t.a., harzhauser, m., georgopoulou, e., mandic, o. & kroh, a. (2014a): replacement names and nomenclatural comments for problematic species-group names in europe‘s neogene freshwater gastropoda.– zootaxa, 3785/3, 453–468. doi: 10.11646/ zootaxa.3785.3.7 neubauer, t.a., harzhauser, m., georgopoulou, e. & wrozyna, c. (2014b): population bottleneck triggering millennial-scale morphospace shifts in endemic thermal-spring melanopsids.– palaeogeogr. palaeoclimatol. palaeoecol., 414, 116–128. doi: 10.1016/j.palaeo.2014.08.015 neubauer, t.a., harzhauser, m., kroh, a., georgopoulou, e. & mandic, o. (2015a): a gastropod-based biogeographic scheme for the european neogene freshwater systems.– earth-sci. rev., 143, 98–116. doi:10.1016/j.earscirev.2015.01.010 neubauer, t.a., mandic, o. & harzhauser, m. (2013a): the middle miocene freshwater mollusk fauna of lake gacko (se bosnia and herzegovina): taxonomic revision and paleoenvironmental analysis.– fossil record, 16, 77–96. doi: 10.1002/mmng.201300003 neubauer, t.a., mandic, o., harzhauser, m. hrvatović, h. (2013b): a new miocene lacustrine mollusc fauna of the dinaride lake system and its palaeobiogeographic, palaeoecologic, and taxonomic implications.– palaeontology, 56/1, 129–156. doi: 10.1111/ j.14754983.2012.01171.x neumayr, m. (1869): ii. beiträge zur kenntniss fossiler binnenfaunen.– jb. k. k. geol. r.-a., 19, 355-382, wien. neumayr, m. (1872): die geologische stellung der slavonischen paludinenthone.– verh. k. k. geol. r.-a., 1872/4, 69. neumayr, m. (1880a): über den geologischen bau der insel kos und über die gliederung der jungtertiären binnenablagerungen des archipels.– denkschr. kaiserl. akad. wiss., math.-naturwiss. cl., 40/1, 213–314. neumayr, m. (1880b): v. tertiäre binnenmollusken aus bosnien und der hercegovina.– jb. k. k. geol. r.-a., 30/2, 463–486. neumayr, m. (1883): zur morphologie des bivalvenschlosses.– sitzber. akad. wiss. wien, 88, 385–419. neumayr, m. & paul, c. m. (1875): congerienund paludienschichten slavoniens und deren faunen. ein beitrag zur descendenz-theorie.– abh. k. k. geol. r.-a., 7/3, 1–106. newell, n.d. (1965): classification of the bivalvia.– american museum novitates, 2206, 1–25. økland, j. (1990): lakes and snails. environment and gastropoda in 1,500 norwegian lakes, ponds and rivers.– backhuys, oegstgeest, 516 p. olivier, g.a. (1804): voyage dans l'empire othoman, l'égypte et la perse, fait par ordre du gouvernement, pendant les six premières années de la république. tome second.– agasse, paris, 466 p. oppenheim, p. (1890): neue oder wenig gekannte binnenschnecken des neogen im peloponnes und im südlichen mittel-griechenland.– z. dtsch. geol. ges., 42/3, 588–592. oppenheim, p. (1891): beiträge zur kenntniss des neogen in griechenland.– z. dtsch. geol. ges., 43, 421–487. oppenheim, p. (1894): ii. tertiäre fossilien.– in: philippson, a. & op-– in: philippson, a. & opin: philippson, a. & oppenheim, p. tertiär und tertiärfossilien in nord-griechenland, sowie in albanien und bei patras im peloponnes.– z. dtsch. geol. ges., 46, 806–822. ožegović, f. (1944): prilog geologiji mladeg terciara na temelju podataka iz novijih dubokih bušotina u hrvatskoj.– vjestnik hrvatskog državnog geologia croatica 68/3geologia croatica 206 geoložkog zavoda i hrvatskog državnog geoložkog muzeja, 2/3, 391– 491. pană, i. (2003): les nannogastropodes.– in: papaianopol, i., mari-– in: papaianopol, i., mariin: papaianopol, i., marinescu, f., krstić, n.& macaleţ, r. (eds.): chronostratigraphie und neostratotypen. neogen der zentrale paratethys, bd. x, pl2. rom-x, pl2. romanien. editura academiei române, bucuresti, 296–349. papaianopol, i. & popescu, d.c. (1997): la faune des mollusques du romanien de greaca (plate-forme moesienne, bassin dacique, roumanie).– acta palaeontologica romaniae, 1, 197–210. papaianopol, i. & macaleţ, r. (2006): les espèces du genre bulimus (gastropoda, mesogastropoda) du néogène supérieur (l’interval pontien-romanien) du bassin dacique.– acta palaeontologica romaniae, 78a, 77–110. papaianopol, i. & marinescu, f. (1995): faune de mollusques daciens du bassin dacique.– in: marinescu, f. & papaianopol, i. (eds.): chronostratigraphie und neostratotypen, bd. ix, pl1. dacien. editura academiei române, bucuresti, 130–267. papaianopol, i. & marinescu, f. (2003): les gastropodes.– in: papaianopol, i., marinescu, f., krstić, n. & macaleţ, r. (eds.): chronostratigraphie und neostratotypen, bd. x, pl2. romanien. editura academiei române, bucuresti, 262–295. papaianopol, i., marinescu, f., krstić, n. & macaleţ, r. (eds) (2003): chronostratigraphie und neostratotypen, bd. x, pl2. romanien.– editura academiei române, bucuresti, 527 p. papaianopol, i., marinescu, f. &macaleţ, r. (1995): stratotypes, faciostratotypes, stratotypes de limite.– in: marinescu, f. & papaianopol, i. (eds.): chronostratigraphie und neostratotypen, bd. ix, pl1. dacien. editura academiei române, bucuresti, 101–125. papp, a. (1953): die molluskenfauna des pannon des wiener beckens.– mitt. geol. ges. wien, 44/1951, 85–222. pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.– basin res., 13, 359–376. pavlov, a.p. (1925): dép�ts néogènes et quaternaires de l'europe mérididép�ts néogènes et quaternaires de l'europe méridi-néogènes et quaternaires de l'europe méridionale et orientale. stratigraphie comparée des couches d'eau douce.– mémoires de la section géologique de la société des amis des sciences naturelles, d’anthopologie et d’ethnographie, 5, 1–215. pavlović, p.s. (1903): građa za poznavanje tercijara u staroj srbiji.–ann. geol. penins. balk., 6/1, 155–189. pavlović, p.s. (1931): o fosilnoj fauni mekušaca iz skopske kotline.– glasnik skopskog naučnog društva, odeljenje prirodnih nauka, 9/3, 1–28. penecke, k.a. (1884): beiträge zur kenntniss der fauna der slavonischen paludienschichten ii. congeria, pisidium, cardium und die gasteropoden.– beitr. paläont. österreich-ungarns, 4/1, 15–44. pfeiffer, c. (1821): naturgeschichte deutscher landund süsswassermollusken. erste abtheilung.– landes-industrie-comptoir, weimar, x + 134 p. pfeiffer, c. (1828): naturgeschichte deutscher landund süsswassermollusken. dritte abtheilung.– landes-industrie-comptoir, weimar, vi + 84 p. pikija, m. (1987a): osnovna geološka karta sfrj 1:100000, list sisak 3393 [basic geological map of sfry 1:100000, sisak sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. pikija, m. (1987b): osnovna geološka karta sfrj 1:100000. tumač za list sisak l33 -93 [basic geological map of sfry 1:100000, geology of the sisak sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd, 55 p. pilar, d. (1873): trečegorje i podloga mu u glinskom pokuplju.– rad jugoslavenske akademije znanosti i umjetnosti, 25, 53–179. pilide, c.d. (1877): über das neogen-becken nördlich von ploesci (walachei).– jb. k.k. geol. r.-a., 27, 131–142. popov, s.v., rögl, f., rozanov, a.y., steininger, f.f., shcherba, i.g. & kovác, m. (2004): lithological-paleogeographic maps of paratethys. 10 maps late eocene to pliocene.– cour. forsch.-inst. senckenb., 250, 1–46. porumbaru, r.c. (1881): étude géologique des environs de craiova, parcours bucovatzu-cretzesci. première partie.– gauthier-villars, imprimeur-libraire, paris, 42 p. prime, t.(1870): catalogue of the recent species of the family corbiculadae.– am. j. conchol., 5, 127–187. rafinesque, c.s. (1815): analyse de la nature ou tableau de l‘univers et des corps organisés.– privately published, palerme, 223 p. rafinesque, c.s. (1820): monographie des coquilles bivalves fluviatiles de la riviere ohio, contenant douze géneres et soixante-huit espèces.– annales générales des sciences physiques, a bruxelles, 5, 287–322. raymo, m.e., grant, b., horowitz, m. & rau, g.h. (1996): midpliocene warmth: stronger greenhouse and stronger conveyor.– marine micropaleont., 27, 313–326. roshka, v.kh. (1973): mollyuski meotica severo-zapadnogo prichernomor'ya.– shtiintsa, kishinev, 284 p. roth, l.v. (1881): beitrag zur kenntniss der fauna der neogenen süsswasser-ablagerungen im széklerlande.– földtani közlöny, 11, 13-24, 64– 76. saftić, b., velić, j., sztanó, o., juhász, g. & ivković, ž. (2003): tertiary subsurface facies, source rocks and hydrocarbon reservoirs in the sw part of the pannonian basin (northern croatia and southwestern hungary).– geol. croat., 56/1, 101–122. salvador, a. (1994): international stratigraphic guide. a guide to stratigraphic classification, terminology, and procedure.– geological soci-geological society of america, boulder, 214 p. sandberger, c.l.f. (1870-1875): die landund süßwasser-conchylien der vorwelt.– c. w. kreidel, wiesbaden. livr. 11, 353-1000 p. (1875). schlickum, w.r. (1972): zur systematik fossiler hydrobiiden 2.– arch. molluskenkd., 102, 93–95. schlickum, w.r. & puisségur, j.-j. (1977): die molluskenfauna des altpleistozäns von st. bernard (département c�te-d’or).– arch. molluskenkd., 107/4/6, 273–283. schlickum, w.r. & puisségur, j.-j. (1978): die molluskenfauna der schichten mit viviparus burgundinus und pyrgula nodotiana von montagny-les-beaune (dép. c�te-d‘or).– arch. molluskenkd., 109/1/3, 1–26. schmid, s. m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine-carpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss j. geosci., 101/1, 139–183. šebečić, b. (2010): o povijesti istraživanja i eksploatacije vuko me ri čkih lignita.– rudarsko-geološko-naftni zbornik, 22, 81–90. sheppard, r. (1825): description of seven new british land and freshwater shells, with observations upon many other species, oncliding a list of such as have been found in the county of suffolk.– trans. linn. soc. london, 14/1, 148–170. sinzov, i. (1877): opisaniye novykh i maloissledovannykh form rakovin iz tretichnykh obrazovaniy novorossii.– zapiski novorossiiskoe obshchestvo estestvoispytatelei, 4, 61–83. sowerby, j. (1812-1815): the mineral conchology of great britain; or coloured figures and descriptions of those remains of testaceous animals or shells, which have been preserved at various times and depths in the earth.– privately published, london, 251 p. stefanescu, s. (1896): études sur les terrains tertiaires de roumanie. contributrons à l étude des faunes sarmatiques, pontiques et levantines.– mém. soc. géol. france. paléont., 4, 1–147. stefanescu, s. (1897): contribution à l'étude des faunes eogène et néogène de roumanie.– bull. soc. géol.france, sér. 3, 25, 310–314. stevanović, p., nevesskaya, l.a., marinescu, f., sokač, a. & jámbor, á. (1990): chronostratigraphie und neostratotypen. neogen der westlichen (“zentrale”) paratethys, bd. viii, pl1. pontien.– verlag der jugoslawischen akademie der wissenschaften und künste und der serbischen akademie der wissenschaften und künste, zagreb, beograd, 952 p. stevanović, p.m. (1951): pontische stufe im engeren sinne – obere congerienschichten serbiens und der angrenzenden gebiete.– srpska akademija nauka, posebna izdanja, 187 (geološki institut 2), 1–361. stimpson, w. (1865): researches upon the hydrobiinae and allied forms: chiefly made from materials in the museum of the smithsonian institution.– smithsonian misc. coll., 7, 1–59. stoica, m., lazǎr, i., krijgsman, w., vasiliev, i., jipa, d. & floroiu, a. (2013): paleoenvironmental evolution of the east carmandic et al.: stratigraphic and palaeogeographic significance of lacustrine molluscs from the pliocene viviparus beds in central croatia geologia croatica 207 pathian foredeep during the late miocene-early pliocene (dacian basin; romania).– global planet. change, 103, 135–148. stoica, m., lazǎr, i., vasiliev, i. & krijgsman, w. (2007): mollusc assemblages of the pontian and dacian deposits from the topologarges area (southern carpathian foredeep romania).– geobios, 40, 391–405. stoliczka, f. (1862): beitrag zur kenntnis der molluskenfauna der cerithienund inzersdorfer schichten des ungarischen tertiärbeckens.– verh.k.k. zool.-bot. ges. wien, 12, 529–538. strausz, l. (1942): viviparen aus dem pannon mittel-transdanubiens.– a magyar királyi földtani intézet évkönyve, 36/1, 1–63. stur, d. (1862): die neogen-tertiären ablagerungen von west-slavonien.– jb. k.k. geol. r.-a., 12, 285–299. stur, d. (1863): bericht über die geologische uebersichts-aufnahme im mittleren theile croatiens.– jb. k.k. geol. r.-a., 13/4, 485–523. swainson, w. (1840): a treatise on malacology or the natural classification of shell sand shell-fish.– in: lardner, d. (ed.): the cabinet cyclopaedia, 122. longman, etc., london, 419 p. sztanó, o., szafián, p., magyar, i., horányi, a., bada, g., hughes, d.w., hoyer, d.l. & wallis, r.j. (2013): aggradation and progradation controlled clinothems and deep-water sand delivery model in the neogene lake pannon, makó trough, pannonian basin, se hungary.– global planet. change, 103, 149–167. taboyakova, v.ya. (1964): opyt biometricheskogo izucheniya pliotsenovykh viviparusov yuga sssr.– trudy paleontologicheskogo instituta, 99, 1–88. takšić, a. (1954): pliocenske naslage okolice novske i nove gra di ške.– geol. vjesnik, 5–7, 149–184. tournouër, r. (1875): note sur quelques fossiles d‘eau douce recueillis dans le forage d‘un puits au fort de vancia, près lyon.– bull. soc. géol. france, 3e série, 3, 741–748. troskot-čorbić, t., velić, j. & malvić, t. (2009): comparison of the middle miocene and the upper miocene source rock formations in the sava depression pannonian basin, croatia).– geol. croat., 62/2, 123–133. tryon, g.w. (1866):[book review of] researches upon the hydrobiinae and allied forms by dr. wm. stimpson, 8 vol. smithsonian institution, washington dc, august 1865, 58 p.– am. j. conchol., 2/2, 152–158. tuccimei, g. (1889): il villafranchiano nelle valli sabine e i suoi fossili caratteristici.– boll. soc. geol. ital., 8, 95–131. uhrin, a. & sztanó, o. (2012): water-level changes and their effect on deepwater sand accumulation in a lacustrine system: a case study from the late miocene of western pannonian basin, hungary.– int. j. earth sci., 101/5, 1427–1440 ustaszewski, k., herak, m., tomljenović, b., herak, d. & matej, s. (2014): neotectonics of the dinarides-pannonian basin transition and possible earthquake sources in the banja luka epicentral area.– j. geodyn., 82, 52–68. van baak, c.g.c., mandic, o., lazar, i., stoica, m. & krijgsman, w. (2015): the slanicul de buzau section, a unit stratotype for the romanian stage of the dacian basin (plio-pleistocene, eastern paratethys).– palaeogeogr. palaeoclimatol. palaeoecol, 440, 594-613. vassoevich, n.b. (1928): notes paléontologiques sur les dép�ts pliocènes et post-tertiares de la presqu‘île de taman.– bulletins du comité géologique leningrad, 47/6, 711–732. welter-schultes, f.w.(2012): european non-marine molluscs, a guide for species identification.– planet poster editions, göttingen, 674 p. wenz, w. (1922): das tertiär im vogelsberg und seine beziehungen zu dem der wetterau und zu anderen tertiärablagerungen.– jahresberichte der wetterauischen gesellschaft für die gesamte naturkunde zu hanau, 1909-1922, 1–82. wenz, w. (1923-1930): fossilium catalogus i: animalia. gastropoda extramarina tertiaria.– w. junk, berlin. volumes vii: 1863-2230 p. (1926), viii: 2231–2502 p. (1928), ix: 2503-2886 p. (1929a), x: 2887-3014 p. (1929b). wenz, w. (1942): die mollusken des pliozäns der rumänischen erdöl-gebiete als leitversteinerungen für die aufschluß-arbeiten.– sen ckenbergiana, 24, 1–293. wijbrans, j., németh, k., martin, u. & balogh, k. (2007): 40ar/ 39ar geochronology of neogene phreatomagmatic volcanism in the western pannonian basin, hungary.– j. volcanol. geoth. res., 164, 193–204. willeit, m., ganopolski, a. & feulner, g. (2013): on the effect of orbital forcing on mid-pliocene climate, vegetation and ice sheets.– clim. past discuss., 9, 1703–1734. willmann, r. (1981): evolution, systematik und stratigraphische bedeutung der neogenen süßwassergastropoden von rhodos und kos/ ägäis.– palaeontogr. abt. a, 174, 10–235. žagar-sakač, a. (1981): über die neogenen unionazeen-arten s. brusina's.– palaeontologia jugoslavica, 27, 1–26. manuscript received july 06, 2015 revised manuscript accepted september 30, 2015 available online october 31, 2015 1. introduction surface geochemical techniques have been used to explore for hy drocarbons ever since the late 1920s. these techniques look for the presence and effects of minute levels of hydrocarbons that migrate through the imperfect seals that cover every reservoir and migrate either as macroseepage via faults or as microseepage vertically through the reservoir overburden (coleman et al., 1977, klusman, 1993, wrigley et al., 2012). direct and in­ direct hydrocarbon indicators can be measured using these me­ thods. hydrocarbons measured on the surface are regarded as direct indicators, meanwhile the results of alternations induced by presence of hydrocarbons can be considered as indirect indi­ cators. soil gases pertain to direct indicators, and radon measure­ ments, which show anomalously high values at the surface due to enrichment in uranium induced by the presence of migrating hydrocarbons, belong to indirect indicators. radiometric mapping, as a petroleum exploration tool, began at the end of 1920s (morse et al., 1982; morse & zinke, 1995). pirson found „halos” of high radiation in a petroleum basin in texas, noting that each halo countered definable regions of lower gamma flux (pirson, 1969). since then, several papers have reported on successful hc exploration strategies using ra­ diometric mapping. palacios et al. (2013) demonstrated posi­ tive radon anomalies around abandoned gas wells, li et al. (2006), dyck & jonasson (2000), ghagremani (1985) used rn­anomalies as one of the indicators of hydrocarbon leaks from the subsoil. landrum et al. (1989) and patrick et al. (2011) highlighted more emissive zones that could be related either to main faults or to secondary fractures acting as migration pathways. statistical and geostatistical study of rn and hydrocarbon components of a soil gas monitoring system: an application to surface hydrocarbon exploration janos geiger1, noémi jakab1, bálint csökmei1, zsolt horváth2 and balázs gellért2 1 university of szeged, department of geology and paleontology; (corresponding author: matska@geo.u-szeged.hu, j.noemi@geo.u-szeged.hu, balint.cs@gmail.com) 2 mol hungary; (zsohorvath@mol.hu, bgellert@mol.hu) doi: 10.4154/gc.2016.20 abstract this work addresses three topics: (1) the study of the joint areal distribution of the rn and hydrocarbon components of soil gases over a large region overlying some known hydrocarbon reservoirs in the southern part of hungary; (2) the relationships between the positive anomalies of rn and hydrocarbon components of soil gases to the existing reservoirs; (3) suggestions for new targets for surface hydrocarbon exploration based on the results. given the very low correlation coefficients between the rn and hydrocarbon components of the soil gases, factor analysis was used to reveal a background process controlling the common migration of hydrocarbon and rn components. the lateral distribution of the factor scores were studied using sequential gaussian distribution. the e-type grid generated from 100 realizations indicated several positive anomalies at the surface. indications with a larger than 0.7 probability were kept for further analysis. seismic sections of a 3d survey support the comparison of the surface locations of these anomalies and the surface projections of the known reservoirs. the results proved the connection between the known reservoirs and the rn and hc components of soil gases. from the positive verification, regions with a high probability positive anomaly of factor scores, but without any reservoir counterparts may be suggested as targets for further surface hydrocarbon exploration. however, most of the existing applications rely only on de­ tecting either direct or indirect indicators. on the ground, not sur prisingly, the geostatistical analysis deals with these sources of information separately. ciotoli et al. (2007) studied the spa­ tial character of a soil gas monitoring system; olivier & kharyat (1999), buttafuoco et al. (2007) dealt with the geostatistics of rn­monitoring systems; maldonato & campbell (1992) or, recently, castillo et al. (2015) used geostatistical tools in the spatial analysis of the hydrocarbon com­ ponents of soil gases. only a few papers have dealt with a geosta­ tistically supported integrated interpretation of the rn and hy­ drocarbon components of soil gases. the aims of this study were to (1) determine the common areal distribution of the rn and hydrocarbon components of soil gases in a large region above some known hydrocarbon reservoirs in the southern part of hungary (fig.1); (2) relate positive anom­ alies of rn and hydrocarbon components of soil gases to the ex­ isting reservoirs, and (3) to suggest new targets for the surface hydrocarbon exploration on the basis of the results. the studied area is located in the southwestern part of hun­ gary, close to the croatian border. in this region, six known hy­ drocarbon reservoirs occur, including from north to south: berzence, somogyudvarhely, vízvár­nord, vízvár, heresznye and görgeteg­babócsa (fig. 1). they were developed in the szol­ nok, algyő and újfalu formations of the miocene sequences. the studied area was also surveyed by 3d seismic survey, the results of which were used in the latter part of this paper to compare and validate the findings of the geostatistical analyses. article history: manuscript received october 31, 2015 revised manuscript accepted april 17, 2016 available online june 28, 2016 keywords: rn monitoring, hydrocarbon reservoirs, factor analysis, sequential gaussian simulation 2016 | 69/2 | 255–268 | 15 figs. | 3 tabs. | www.geologia-croatica journal of the croatian geological survey and the croatian geological society g eo lo gi a c ro at ic a geologia croatica 69/2256 the basic geochemical theory the parent­elements of radon are supposed to migrate from the subsurface hc­reservoir. essentially, they are 238u, 230th and 226ra. radon (rn) can appear in two different decay series: (1) 238u ® 226ra ® 222rn (2) 232th ® 224ra ® 220rn although radium (ra) appears in both decay series, the two isotopes (222ra and 220ra) are not identical: their difference lies in their half­lives. the half live of 222ra (from 238u) is 38 days, while it is only 55 seconds for 220ra (from 232th). when equal quantities of each isotope are available under the same physical environment, the average travel distance of 222ra is around 100 cm, whereas that of 220ra is only 1 cm. that is why 222ra is ex­ pected to make much more of a contribution to the gamma flux. the literature explains that the geochemical background of radiometric signals measured above hydrocarbon reservoirs is very wide. some authors (e.g. armstrong & heemstra, 1973, saunders et al., 1993) proposed that deep seated hydro­ carbon pools provided the sources of radionuclides and their pro­ geny. they thought that radionuclides were transported by forma­ tion fluids from the deep pool, along some hypothetical pathways, up to the surface. in their view, relatively high gamma emissions form the „halo”, while low emissions exist within the boundary of the halo. morse & zinke (1995) provided an elegant interpretation for the formation of the radiological „halo”. their theory was bas ed on laubmeyer’s concept of vertical gas migration. in this process, with the passage of time, low molecular weight hydro­ carbons migrating upward induce a chemically reducing environ­ ment in zones overlying the hydrocarbon (hc) accumulations. when oxidized uranium enters into this zone, its upward move­ ment stops. consequently, the uranium concentration becomes lower than it would have been with no hydrocarbon present. the uranium attempting to transit into the reducing zone will preci­ pitate at the zone boundary. this precipitation appears as a halo as reported by pirson (1969). the theories say that the radiation anomalies are not directly connected to the deep hc reservoirs. rather, “geochemical cells”, developed above the hc reservoirs, initialize such geochemical changes which cause the adsorption of the uranium content of the formation fluids. radon, as the most mobile member of uraniumdecay, can give effective information about these anomalies. kristiansson & malmqvist (1982) explained the non ­diffusive transport of rn by carrier­gas transport. one of the most complete theories for the relationship between the subsur­ face reservoirs and the surface radiological measurements are given by tedesco (1995). in tedesco’s theory, a geochemical cell with the cloud of inverse electric charge develops between the (subsurface) reservoir and the surface. it initializes the migra­ tion of ionic geochemical constituents. it is very important to note that only the long­lived parent elements of rn take part in this process. radon is only a tracing element of this process, which can migrate via microseepage in a water­saturated permeable agent. várhegyi et al. (2008) supposed that vertical migrations of formation fluid and gas can be connected to the subsurface hc accumulations which carry radionuclides from the formations be tween the reservoirs and the surface. in this case the source of radioactive elements is not the hc reservoir, but the rock bodies lying above the hc layers. the reservoir only initializes the fol­ lowing simplified transport mechanism: hc reservoir ® geo­ chemical cell ® change of redox conditions near the surface ® selective adsorption of the dissolved uranium at the redox­fronts ® uranium­radium and radium­radon transformation ® upward migration of radon. figure 2. shows this combination of the hy­ pothesized geochemical cell and the microseepage transport model of rn migration (várhegyi et al., 2008). in this imple­ mentation the geochemical cell and the connected microseepage transport model of rn assume high water saturation. the migra­ tion processes slows down above the surface of underground water. there is no chance of detecting rn indication if the water surface is below 10 m (várhegyi et al., 2008). in summary, it can be concluded that the radiation anomalies are not directly connected to the deep hc reservoirs. rather, “geo chemical cells” developed above the hc reservoirs initialize such geochemical changes which cause the adsorption of the ura­ nium content onto the formation fluids. radon, as the most mo­ bile member of uranium­decay, can give effective information about these anomalies. figure 1. study area. g eologia c roatica geiger et al.: statistical and geostatistical study of rn and hydrocarbon components of a soil gas monitoring system ... 257 the critical point in the applicability of the research­method based on radon detection is the differentiation of the deep origin and the background radiation. várhegyi et al. (2008) have de­ veloped a method for measuring this. 2. soil gas and radiological measurements 2.1. soil gas measurements during the radon-monitoring field measurements, a specified mass (12 g on average) of soil was taken for the headspace gas method of soil gas analysis. the samples were placed into a glass container of 20 ml volume, and sealed by a rubber membrane. this glassware was then heated at 85 °c for 20 minutes prior to gas­chromatographic measurement. the headspace of the glass container was sampled by syringe through the membrane and the gas sample in the syringe was injected into a gas-chromatograph with an fid detector. with this apparatus, simple hydrocarbons c1, c2, c3, nc4, ic4, nc5 and ic5 (methane, ethane, propane, normal butane and isobutane, normal pentane and isopentane) were measured. to assess the reliability of the measurements, how the concentrations of hydrocarbon components decreased in “natural” and “artificial” soil samples were analyzed in the labo­ ratory. from the measured hydrocarbon components (hc), only c2, c3, nc4 and nc5 are involved in the further statistical and geostatistical analysis. 2.2. analysis of the 222rn concentration of soil gas the samples were taken in a regular surface grid where the nodes were 250 m apart. the change of background ra radiation was followed by the so called basic registrations process. in the moni­ toring locations, three other properties were measured and cal­ culated besides the 222rn concentration. they were the uranium equivalent of the 222rn concentration (uern), the difference be­ tween 222rn and 226ra (rn­ra), and the so called soil­corrected 222rn (rn­ai) content. the uranium equivalent of the measured rn concentration (uern) was defined as the concentration of the parent element of rn in the soil. it was directly measured using gamma­spectro­ metry. under general conditions, the 226ra concentration of the soil environment is the origin of the 222rn concentration. how­ ever, migration processes can increase or decrease this “regular” 222rn concentration. when the migration adds rn to the “regu­ lar” concentration, this rn­ra difference is positive, otherwise it is zero or negative. the local characteristics of soil geochemistry and its physical properties can significantly affect the rn concen­ tration. the effects of these features on the local rn concentra­ tion can even be much larger than those of the migration proce­ sses. that is why correction of the measured concentrations to the soil­variability was of primary importance. the samples were grouped in k sets with homogeneous soil characteristics, , 1,2, ,= …ks k k . then everages and variances were calculated for each set, , 1,2, ,= …ks k k . finally, ( ) − k jrn ai was determined for each sample as a “standardized” value: ( ) ( ) ( ) ( )s − − = k k jk j k rn mean rn ai (1) where k jrn is the rn content of the sample, ( ) 1,2, ,= …thj j j in group ( ) 1,2 ,= …thk k k , ( )kmean is the average, and ( )s k is the variance of the rn content in ( ) 1,2 , group= …thk k k . note that ( )− k jrn ai can have positive and negative values. 3. field data collection and its descriptive statistics the geochemistry suggested that only the c2 (ethane), c3 (pro­ pane), nc4 (normal butane) and nc5 (normal pentane) compo­ nents of the hc gases were worth keeping in the statistical­geo­ statistical modeling, since they could be expected to be of deep origin. all these components were expressed in ppb. in contrast, all the parameters measured or calculated in the radiological mo­ nitoring were involved in the analyses. they were as follows: rn (radon content of soil gas, in kbq/m3), uern (uranium equivalent figure 2. a geochemical model of the radiation anomaly above hydrocarbon reservoirs várhegyi et al., 2008. g eo lo gi a c ro at ic a geologia croatica 69/2258 of the rn content, in ppm), rn­ra (the difference between rn and ra components, in kbq/m3), and rn­ai (rn measurements corrected by the soil environments, dimensionless). in the sampling process of soil gas and radon­monitoring, 2441 samples altogether were analyzed. however, among them there were only 538 in which all the parameters could have been measured (fig. 1). they were the target of the geomathematical analyses. table 1. shows their general statistical characteristics. since the hydrocarbon components had very skewed probability distributions, their original values were transformed by a log10 function before calculation of the statistics in table 1. the minimum value of rn­ra, in table 1, has a negative sign indicating that there were sampling locations from where the rn migrated into the surroundings. however, the high positive value of the maximum rn­ra property indicated that there were sam­ pling sites where the migrated rn content were added to those generated “in situ” (table 1). the correlation coefficients between the radon and hydro­ carbon components in table 2 (coloured light grey) were signifi­ cant, but the deterministic coefficients (r2) of the highest correla­ tions between the rn and hc components were, at best, 0.04. simulation in the analysis of the spatial distribution. this ap­ proach does give the best estimation, but tends to honour the sta­ tistical characteristics while emphasizing the small scale hetero­ geneities (mucsi et al., 2013). 3.1. methods used in the statistical and geostatistical modeling the workflow of statistical and geostatistical analysis shows the steps in which field and surface seismic data are integrated and their spatial connections revealed (fig. 3). the statistical and geostatistical analyses were based on three principles. (1) the factors were regarded as compact sum­ marizations of the background processes affecting the rn­and hc­components. because factors represented continuous spatial processes in the joint migration of rn and hydrocarbon gases, they could be regarded as continuous spatial variables and ana­ lyzed by geostatistical tools. (2) because of the scattered sam­ pling, the spatial uncertainty of the geostatistical model was also important to study. (3) the final goal was to indicate the proba­ bility of those regions where the co­variability of rn­and hc components could suggest hc structures at depth. 3.2. factor analysis factor analyses are very effective tools of linear data integration. the main applications of factor analytical techniques are to re­ duce the number of variables and to detect structure in the rela­ tionships between variables, that is, to reduce data dimensiona­ lity. here, we used this technique in the latter sense, as a structure detection method. in this so called exploratory factor analysis (efa) we tried to uncover complex patterns by exploring the da­ table 1. descriptive statistics of the variables analyzed. variables valid n mean median minimum maximum standard deviation rn (kbq/m3) 538 35.39 30.38 1.00 176.50 24.95 rn-ra (kbq/m3) 538 –0.88 –5.34 –81.76 145.30 23.13 rn-ai (dimensionless) 538 0.02 0.11 –3.86 2.89 1.00 log(c2) (ppb) 538 0.90 0.90 –0.67 2.68 0.41 log(c3) (ppb) 538 0.26 0.24 –0.74 2.56 0.35 log(nc4) (ppb) 538 –0.21 –0.24 –1.04 2.78 0.31 log(nc5) (ppb) 538 0.07 –0.15 –0.95 1.98 0.37 table 2. correlation coefficients between the variables. variables correlations (n=538) rn rn-ra rn-ai log(c2) log(c3) log(nc4) log(nc5) rn 1.00 0.77 0.78 –0.17 –0.12 0.02 –0.01 rn-ra 1.00 0.73 –0.01 –0.03 0.04 0.02 rn-ai 1.00 –0.02 –0.06 0.01 0.05 log(c2) 1.00 0.75 0.47 0.46 log(c3) 1.00 0.63 0.55 log(nc4) 1.00 0.49 log(nc5) 1.00 these results were the consequences of very heterogeneous soil types, and the temperature and humidity differences between the sampling periods. this fact (among others) had three important consequences: (1) it was not possible to make a direct comparison of rn and hc components; (2) instead of forcing the analysis of their pairwise relations, the pattern of their inter­correlations was targeted in the analysis; (3) quite high uncertainty could be ex­ pected in the measured data. point (2) meant that a factor analysis as a data integration tool could be expected to reveal the connections between the hc and rn components (jöreskog et al., 1976; olivier & kharyat, 1999). point (3) suggested the use of a stochastic figure 3. workflow of analysis strategy. g eologia c roatica geiger et al.: statistical and geostatistical study of rn and hydrocarbon components of a soil gas monitoring system ... 259 taset and testing predictions (child, 2006). efa is used when the aim is to discover the number of factors influencing variables and to analyze which variables ‘go together’. a basic hypothesis of efa is that there are m common ‘latent’ factors ( 1 2, , , … mf f f ) to be discovered in the dataset, and the goal is to find the small­ est number of common factors, p , that will account for the cor­ relations of the variables, 1 2, , , … px x x (mcdonald, 1985). the model assumes that each observed variable is a linear function of these factors together with a residual variance. this model intends to reproduce the maximum correlations. 1= = ⋅ +∑ m j ji i j i x a f e (2) where ( ) 1, 2, , = …jia i m are the factor loadings, and je is the specific or unique factor. generally, a factor analysis decomposes the modified corre­ lation matrix. the modification is that the original diagonal ele­ ments (they equal to 1) of the correlation matrix are replaced by the prior communality estimates. it means that this technique does not decompose the whole variance of each variable since it may also have error variance. the estimated proportion of vari­ ance of the variable (communality) is assumed to be free of error variance and is shared with other variables in the matrix. it is the variance of a variable in common with all others together (com­ munalities are smaller than 1). in this way factor analysis gives enough room to take measurement error and measuring uncer­ tainty into consideration. one of the most convenient ways to interpret the results of factor analysis is the interpretation of factor loadings. the factor loadings are the correlation coefficients between the variables and factors. they represent to what extent a variable is explained by a factor. analogous to pearson’s r , the squared factor loading is the percent of variance in the particular indicator variable explained by the factor. loadings can range from (­1) to 1. loadings close to (­1) or 1 indicate that the factor strongly affects the variable. in the interpretation of factor loadings the first important decision is to identify the high loadings. there is a rule of thumb saying that loadings should be 0.7 or higher. the rationale of this statement is that the 0.7 level corresponds to about one half ( 20.7 0.49)= of the variance in the indicator being explained by the factor. how­ ever, some researchers, particularly for exploratory purposes, use a lower level such as 0.4 for the central factor and 0.25 for other factors. in any event, factor loadings must be interpreted in the light of theory, not by arbitrary cutoff levels (stevens, 2002). factor analysis can also be viewed as a transformation of the original sample space (defined by the original variables) into an orthogonal space defined by the factors. the coordinates of this factor space are called factor scores. computing factor scores fa­ cilitates the search for factor outliers. also, factor scores may be used as variables in subsequent modeling. here the main goal was to reveal such a factor in which both the rn and all the hydrocarbon components appear with high positive factor loadings. after several trials a special factoring algorithm was discovered in which these requirements have been realized. in this algorithm the communality was approached by the multiple correlation coefficients, and we used the centroid method (thurstone, 1931) to extract the factors. the eigen values of the extracted factors were larger than 1. the rationale of this criterion was that the variance of the defined factor should be at least as large as that of each standardized variable. the cut­ off for the definition of a high factor score was 0.5. for each sam­ ple the factor scores were also calculated. factor scores represent the amount of the effect of the actual factor exercised in each ob­ ject (sample). consequently, the areal distribution of factor scores could be expected to show the areal variability of the ‘hidden’ process controlling the joint migration of rn and the hydrocarbon components of soil gases. 3.3. geostatistical tools 3.3.1. variography in the geostatistical literature, spatial patterns are usually de­ scrib ed in terms of the dissimilarity (instead of similarity) be­ tween observations as a function of the separation distance. the average dissimilarity between data separated by a vector h is measured by the experimental semivariogram ( )g h , which is computed as half the average of the squared difference between the components of every data pair: ( ) ( ) ( ) ( ) ( ) 2 1 1 2 g =  = − + ∑ n h i i i h z u z u h n h (3) where ( )n h is the number of data pairs for a given distance. the main purpose of the variogram calculation is partly to analyze the directional heterogeneity, and partly to transfer this information to kriging or simulation procedures. therefore, a continuous function must be fitted to the values of the experimen­ tal variograms so as to deduce semivariogram values for any pos­ sible lag h required by prediction algorithms and also to smooth out sample fluctuations. the difficulty is that only conditionally negative definite functions can be considered as semivariogram models, in order to ensure the non­negativity of the variance of the prediction error. in practice, only a few models are known to be permissible (e.g. deutsch & journel, 1998, deutsch 2002 or goovaerts, 1997). typically, two or more permissible models must be combined to fit the shape of the experimental semivariogram. combinations of permissible models are permissible as long as the contribution of each basic model is positive, that is the nested model is writ­ ten as: ( ) ( ) 0 0g = = ≥∑ l i i i i h b g h with b (4) where ib is the positive sill or slope of the corresponding basic semivariogram model ( )ig h . the variogram map (sometimes called variogram surface) takes the idea of calculating the variogram in a number of direc­ tions. it can be created by posting the variogram values on a map, where the center of the map is the lag distance of zero (e.g. isaaks & srivastava, 1989 or deutsch, 2002). the way in which the permissible models are chosen and their parameters (range, sill) are estimated is still controversial (mcbratney & webster, 1986; goovaerts, 1997). there are several ways to check the goodness-of-fit of the per­ missible model. it can be done per view, or using some criteria based on minimizing the least square differences between the experimental and fitted model. however, the tool of variogram map can also be applied for this purpose. by comparison of the variogram map coming from original data and that of variogram models, the goodness of the variogram models can be evaluated. 3.3.2. cell declustering the sample points in this study show neither regular nor random spatial distribution over the region (fig. 1). this kind of ‘sam­ pling’ is said to be preferential. this situation means that the available samples are quite far from statistical representativity. consequently, neither the summary statistics of the data set nor g eo lo gi a c ro at ic a geologia croatica 69/2260 the shape of the histograms of the measured attributes may be representative for the entire volume of interest. although most contouring or mapping algorithms adjust this preferential clustering by default, simulation algorithms fail in the process. these methods rely on the “intrinsic” assumption of the sample distribution being representative of the entire volume of interest (deutsch, 2002). since the “very­leaky” spatial ar­ rangements needed the application of stochastic simulations, the situation amounts for data­“declustering”. there are two com­ monly used solutions: the polygonal method (isaaks & srivastava, 1989; goovaerts, 1997; geiger, 2012) and the so called cell­declustering approach (journel, 1983; deutsch, 1989; goovaerts, 1997; geiger, 2012). in this study we used the latter method. the cell-declustering approach calls for definition of a grid system over the a area of interest and counting the number b of cells that contain at least one datum and the number bn of data falling within each cell b. then the weights are defined as: 1 , 1,2, , = = ⋅ j b w j n b n (5) these weights are inversely proportional to the number of data in each cell. hence, these weights give more importance to isolated locations. a weight greater than 1 implies that the sam­ ple space is being over weighted, and a weight less than 1 shows that the corresponding location is being under weighted. in the latter case it is clustered with other locations. in the implementations the “best” cell size for declustering the sample points can be recognized by plotting the declustered mean versus cell size for a range of cell sizes. from this plot the size with the lowest declustered mean should be chosen when data are clustered in high­valued areas or the size with largest declustered mean in the inverse situation (deutsch, 1989). 3.3.3. sequential gaussian simulation consider the simulation of the continuous attribute z at n grid nodes , iu conditional to the data set ( ){ }, 1, 2, , = …iz u i n . sequential simulations (journel & alabert 1988; isaaks, 1990; gómez­hernández & srivastava, 1990; malvic, 2008) amount to modeling the conditional cu­ mulative distribution function (ccdf): ( )( ) ( ) ( ){ }, ,; | |= ≤i i i if u z n u prob z u z n u , (6) then sampling it at each of the grid nodes visited along a random sequence. to ensure reproduction of the z ­semivariogram mo­ del, each ccdf is made conditional not only to the original n data but also to all values simulated at previously visited locations. other realizations are obtained by repeating the entire sequential drawing process. sequential gaussian simulation (sgs) typically involves a prior transform of the z ­data into normal score data. the simulation is then performed in the normal space and the simulated normal scores are back­transformed in order to iden­ tify the original z ­histogram. 3.3.4. goodness of the probabilistic model (simulation) the goodness of a probabilistic model may be checked by its ac­ curacy and precision. in general, accuracy refers to the ultimate excellence of the data or computed results, e.g. conformity to truth or to the standard. precision refers to the repeatability or refine­ ment (significant figures) of a measurement or computed result. deutsch (1997) proposed specific definitions for these terms. in his view accuracy and precision were based on the ac­ tual fraction of true values falling within symmetric probability intervals of varying with p. a probability distribution is accurate if the fraction of true values falling in the p interval exceeds p for all p in [0,1]. the precision of an accurate probability distri­ bution is measured by the closeness of the fraction of true values to p for all p in [ ]0,1 . stochastic simulation leads to l stochastic realizations at each data location. these realizations provide a model for the conditional cumulative distribution function (ccdf): ( )( ) ( ) ( ){ }; | |= ≤i i i if u z n u prob z u z n u (7) where ( )in u is the set of n data at location iu . these local models may be derived from a set of l realizations, calculated from in­ dicator kriging or defined by the gaussian mean, variance and transformation. the probabilities associated with the true values ( ), 1, 2, , = …iz u i n ( ), 1, 2, , = …iz u i n are calculated from the previous ccdf as ( )( ); | .i if u z n u consider a range of symmetric p ­probability intervals (pis). the symmetric −p pi is defined by the corresponding lower and upper probability values: 1 1 2 2 − += =low upp p pp and p (8). next, define an indicator function ( );x iu p at each location iu as: ( ) ( )( ) ( )1, ; | , ; 0, x  ∈=   i i low up i if f u z n u p p u p otherwise . (9) the average of ( );x iu p over the n location iu : ( ) ( ) 1 1 ;x x = = ∑ n i i p u p n (10) is the proportion of locations where the true value falls within the symmetric −p pi . according to the earlier definition of accuracy, the simula­ tion algorithm used to generate the ccdfs is accurate when ( ) , x ≥ ∀p p p. a grapcal way to check the assessment of accu­ racy is to plot ( )x p versus p and to see if all of points fall above or on the 45° line. this plot is referred to as an accuracy plot (deutsch, 1997). 3.3.5. analyses of uncertainty the advantage of stochastic simulation over interpolation (kri­ ging) is that it allows the reproduction of statistics (histogram, semivariogram, scattergram) inferred from the data, hence the model or realization looks more “realistic” than a smooth esti­ mated map. also, one can generate multiple realizations that all reasonably match the same sample statistics and exactly identify the conditioning data. the set of alternative realizations provides a visual and quantitative measure (actually a model) of spatial uncertainty. spatial features are deemed certain if seen on most of the simulated maps. conversely, a feature is deemed uncertain if seen only on a few simulated maps. simulation can be accom­ plished using a growing variety of techniques, which differ in the underlying random function model (multigaussian or nonpara­ metric), the amount and type of information that can be accounted for, and the computer requirements (gotway & ruther­ ford, 1994; srivastava, 1996; deutsch & journel, 1998). according to srivastava (1996), geostatistical realiza­ tions can be used for three main purposes: (1) assessing the im­ g eologia c roatica geiger et al.: statistical and geostatistical study of rn and hydrocarbon components of a soil gas monitoring system ... 261 pact of uncertainty; (2) reproducing the spatial variation; (3) per­ forming monte­carlo risk analysis. the concept of space of uncertainty, and the associated issue of equiprobability of reali­ zation were discussed in detail in the 1990s (e.g. journel, 1994; srivastava, 1994). some authors believed that the space of uncertainty must have been theoretically defined outside the use of a particular algorithm. others stated that the space of un­ certainty could only be defined through the algorithm and con­ sists of all possible realizations that could be generated by the algorithm. there is currently no theory that allows us to determine the set of all possible outcomes if fairly sampled. the characteriza­ tion of the space of uncertainty is rendered difficult by the fact that only a limited number of realizations is usually generated. the uncertainty can be quantified by measures such as en­ tropy, interquartile range, or variance. in this paper, the variance was preferred because of its simplicity and wide acceptance as a measure of spread. the uncertainty of a probabilistic model was defined as the average conditional variance of all locations in the area of interest: ( )2 1 1 s = = ∑ n i i u u n (11) where there are n locations of interest , 1, 2, , = …iu i n with each variance ( )2s iu calculated from the local ccdf ( )( ); |i if u z n u . 3.3.6. probability maps sgs results in the generation of conditional cumulative probabi­ lity distributions (ccdf) at each grid node via the calculation of stochastic realizations. hence, calculation of any probability in the sense of (7) is quite straightforward at grid nodes if we have large enough number of realizations. the 100 equally probable values simulated in grid nodes provided the possibility of this derivation. the accepted geochemical model said that the migra­ tion process of interest could be made probable in the region of “high” factor scores. if the cut­off of these high factor scores were known, the probability belonging to this cut­off in each grid node would characterize the possibility of the migration process in grid nodes. this thought needed two practical steps: (1) finding a cutoff to define “high” scores of the factor describing the migration process; (2) contouring the probability of this cut­off. for the definition of cut-off of “high” scores, −cut offscore , two approaches were considered. the first was the box and whisker plot technique (tukey, 1977), the second being the ( )s+mean approach, where s was the standard deviation. the latter pro­ vides an inflection point of the normal distribution. from these two definitions the latter was used in further analysis, since this gave a larger number of regions on the map to be compared with the seismic data. after choosing the proper cut­off, we calculated the ( ) cut off iprob score scores of factor− ≤ (12) probabilities in each grid node from the 100 simulated values. in this probability map, regions outlined by high probabilities were expected to show the surface projections of the subsurface. 3.3.7. comparing geostatistical results and 3d seismic the 3d seismic covers almost the whole sampling area. in the seismic data sets, analysis of average amplitude and the interpre­ tation of some seismic attributes have occurred. as a result, all the known subsurface reservoirs and the most important faults have been identified. three sections were cut from the 3d seis­ mic data set. their traces are shown in fig. 4. along these poly­ lines three transects were created from the probability map. these transects were compared with the corresponding seismic sections. this facilitated the checking of whether the structures appearing in the probability map coincided with the subsurface reservoirs or that such a fault system could be a potential pathway for the common geochemical migration of hydrocarbon and pa­ rent elements of rn. 4. results the result of factor analysis showed only two factors meeting the initial criterion (let the eigenvalue be larger than 1). the two (un­ rotated) factors shown in table 3. described 65% of the total vari­ ance. they defined almost equal proportions of the total variance: 31.5% and 34.1% respectively. the first factor positively correlated all the other variables (table 3, factor 1). therefore we supposed it reflected a complex process increasing both the hc and the rn components of soil gases. consequently this factor was called a “factor of migra­ tion”, which was exactly what we were looking for. its low con­ tribution to the total variance could be explained by the high de­ pendence of rn components on the very variable physical en vironment: humidity, soil type, season of measurements, etc. on the basis of the applied geochemical model this factor was expected to outline regions, surrounding the surface projections figure 4. the five traces of seismic sections. table 3. the result of factor analysis (high factor loadings are colored by light grey). variables unrotated factor loadings extraction: principal factors (centroid) factor 1 factor 2 rn 0.536540 –0.736023 rn-ra 0.570151 –0.623170 rn-ai 0.571089 –0.643253 log(c2) 0.526628 0.540717 log(c3) 0.659843 0.652462 log(nc4) 0.545612 0.420220 log(nc5) 0.501242 0.389047 proportion of total variance 0.314396 0.341410 g eo lo gi a c ro at ic a geologia croatica 69/2262 figure 5. lateral distribution of factor 1 scores (a), frequency distribution of declustered factor 1 scores (b), normal scores of declustered factor 1 scores (c). figure 6. empirical variogram map of the normal scores of factor 1 scores (a), variogram models of the normal scores of factor 1 (b), variogram map of the variogram model of (c). g eologia c roatica geiger et al.: statistical and geostatistical study of rn and hydrocarbon components of a soil gas monitoring system ... 263 of the existing subsurface reservoirs (“positive radon anomaly” in fig. 2). the second factor showed a high positive correlation with all the rn and high negative correlations with hydrocarbon compo­ nents, which was inconsistent with the assumed geochemical process. even the information content of this factor was very low: it was able to explain only 3% of the total variability by itself (ta­ ble 3, lowermost row) and is why factor 2 was ignored at the next stage of modelling. the lateral distribution of factor 1 scores appeared with high positive values in the southern part of the studied area (fig. 5, a). the clustered appearance of the sample locations required a cell declustering approach to get more representative descriptive sta­ tistics of the frequency distribution. the frequency distribution derived from the declustered data is skewed toward the high pos­ itive figures (fig. 5, b). the normal score transformation of original declustered factor 1 scores is shown in fig. 5, c. the variogram maps calculated for the normal score trans­ formations of the factor 1 scores showed a definite ne-sw con­ tinuity direction (fig. 6 a). the empirical continuity expressed by the variogram map was modeled by a nested theoretical vario­ gram model: ( ) ( ) ( ) ( )0.63 0.26 .2000 0.14 .1400 0.03 .2400h exp h gauss h gauss hg = + ⋅ + ⋅ + ⋅ ( ) ( ) ( ) ( )0.63 0.26 .2000 0.14 .1400 0.03 .2400h exp h gauss h gauss hg = + ⋅ + ⋅ + ⋅ (13) where the directions and the anisotropy ratios were 118°, 40°, 35°, and 0.76, 40 and 50, respectively. in this model, the short small scale heterogeneity had 1400 m of range, while 2400 m of range belonged to the large scale hete­ rogeneity. the nugget effect was very large (0.63 in (13)) expressing that about 60% of the total spatial variability cannot be characterized by any linear geostatistical model. variogram maps calculated from the models honoured the main anisotropic-characters of factor 1 (fig. 6, c). it can also be seen that the models did not cover the whole of the initial hetero­ geneity. however, the comparison of model and empirical vari­ ograms proved that this loss of information was beyond the range (fig. 6 a, c). using the variogram model and declustering weights, 200 equally probable stochastic realizations were generated by se­ quential gaussian simulation. the simulated normal scores were back­transformed to the original scale of the factor 1 score. we checked the simulation results by the accuracy plot (fig. 7) and a visual comparison of the distributions of original and simulated scores (fig. 8). since points in the accuracy plot of the simulation results lie above the 45° line, the result of the simulation was ac­ curate, but not exact (fig. 7). figure 8. shows both the original and simulated factor 1 scores. the spatial dependence of the factor 1 scores did not al­ low the use of any statistical test. by visual examination we could say that the simulation decreased the minimum of the input data set. fortunately, this did not affect the acceptance of the simula­ tion, since we were looking for the high positive and not for the low negative factor scores. in grid nodes, the e­type estimation for factor 1, was calcu­ lated from the backtransformed normal scores (fig. 9). the grid­average of the factor 1 scores and their variance were –0.072 and 0.192, respectively. the ‘high’ scores were de­ fined as those being larger than the expected value plus variance. in fact, this definition produced a larger set than that of the boxplot (fig. 10). consequently it resulted in higher possibilities in the lateral outlining of the area with high factor 1 scores. these laterally continuous regions of high factor 1 scores were the targets which we were looking for. figure 7. accuracy plot of the simulation. figure 8. comparisons of original (a) and simulated (b) factor 1 scores. g eo lo gi a c ro at ic a geologia croatica 69/2264 the map of conditional variance was used to characterize the uncertainty of the stochastic model from which the e­type esti­ mation was derived (fig. 11, a). this map suggested that although the general uncertainty was low in most of the area, there was a very definite subregion with high uncertainty. fig. 11b shows the stack map of the e­type estimation (3d surface in fig. 11b) and the contours of conditional variance (contour map above the 3d surface in fig. 11b). this processing clearly shows that the high­ est uncertainty coincided with a subregion of high factor 1 scores. the probability map showing the probability of locations where factor 1 scores were larger than the lower boundary of the high scores, 0.120 (mean+variance) was derived from the stochas­ tic realizations (fig. 12, a). on this map, at least six larger conti­ nuous subregions of high probabilities could be easily recognized. these were expected to reflect the subsurface hydrocarbon reser­ voirs. three transects were cut out from the probability grid along the surface projections of the seismic sections (fig. 12, b,c and d). along the first transect (i-ii in fig. 13) we identified an al­ most typical halo geometry of high factor 1 scores (fig. 13, i). figure 12, ii demonstrates the seismic section along this transect. the lateral extension of vízvár and vízvár-north fields could be identified in the probability transect. the southern anomaly of factor 1 scores (heresznye­anomaly in fig. 13) appeared with more than 0.7 probability and matched with the subsurface posi­ tion of the vízvár field. the northern anomaly was a typical halo­ anomaly corresponding to the subsurface location of the vízvár­ north field. the second transect (iii to iv in fig. 12) went through three characteristic anomalies of factor 1 scores appearing with more than 0.7 probability. they were, from nw to se, the berzence, somogyudvarhely and heresznye anomalies (fig. 14). among them somogyudvarhely and heresznye developed above the víz­ vár hydrocarbon field, but there was no known equivalent hydro­ carbon accumulation below the berzence anomaly (fig. 14). the third transect also crossed three spots of high factor 1 scores: somogyudvarhely, vízvár­north and the komlósd anoma­ lies. the probability of their appearance was more than 0.7 (fig. 15). the subsurface counterparts of vízvár­north and komlósd were figure 9. e-type estimation of factor 1 scores from 200 stochastic realizations. figure 10. comparison of the sets of “high factor 1 scores defined by the boxplot and (e + s) techniques. e is the expected value of the distribution; s is the standard deviation of the distribution. g eologia c roatica geiger et al.: statistical and geostatistical study of rn and hydrocarbon components of a soil gas monitoring system ... 265 the vízvár­north and görgeteg­babócsa fields. the miocene fault appearing below the somogyudvarhely anomaly was re­ garded as being the genetic background of this anomaly. 5. discussion and conclusion the presented statistical and geostatistical analysis of the rn and hc components of soil gas samples was based on two expecta­ tions. firstly, that the process controlling the common migration of these components could be recognized by a particular factor in the factor matrix of the studied components. the consequence of this hypothesis was that the strength of this process could be characterized by the scores of this factor. secondly, that the regional appearance of this migration process could be analysed by the tools of stochastic simulations. the choice of stochastic simulation was supported by two facts: (1) after filtering out some ‘uncertain’ results of the hc gas analyses, the remaining samples showed a very scattered pattern; (2) the factor scores were not direct measurements of the migration process, consequently we had to use probabilistic approaches. the basis of the factor analysis approach was the lack of any strong correlation between the hc and rn components. in fact, the application of factor analysis did not follow the traditional way, in which the first few factors are used in the interpretation. in this study we searched for “the” factor correlating with both the rn and ch components. in this strategy we accept, that the radiological and hc properties of soil gases could be affected by several processes. it was also admitted that the targeted phenom­ enon (factor expressing the joint migration of rn and hc gases) figure 11. a: the uncertainty of the stochastic model by which the e-type estimation was derived (a); b: stacked map of the e-type estimation (3d surface) and the conditional variance (contour map above the 3d surface). figure 12. map showing the lateral distribution of prob(factor 1 > 0.120). a: probability contours with the surface projections of seismic sections (i to vi). b, c and d are the transects created along the surface polygons of the seismic sections. g eo lo gi a c ro at ic a geologia croatica 69/2266 figure 13. correlation of the probability map of high factor 1 scores and the subsurface hydrocarbon fields along the first transect. figure 14. correlation of the probability map of high factor 1 scores and the subsurface hydrocarbon fields along the second transect. g eologia c roatica geiger et al.: statistical and geostatistical study of rn and hydrocarbon components of a soil gas monitoring system ... 267 might be not necessarily the dominant process. for the purpose of this study, the only important thing was the existence of such a factor. this was the main reason for (1) the application of only the unrotated factor matrix and (2) the spatial analysis of factor 1 even if it did not have high communality. the loadings in factor 1 showed exactly what we were look­ ing for: the higher the rn content, the higher the ch content is (table 3). this result was in absolute harmony with the basic ge­ ochemical theory (fig. 2). in factor 2, the signs of factor loadings belonging to the rn and hc component were contradictory. this process could be characteristic above such regions, where the vertical migration of hc gases slowed down while the migration of the rn components did not change significantly. these phe­ nomena may be characteristic above the water phase of the rese­ rvoirs. unfortunately this situation could not be checked on the basis of the available seismic survey. the spatial analysis of the factor scores highlighted some spatial outliers. for example, in figure 5a, a high score appeared (red dot on the map) among average scores (green and blue dots). under regular circumstances, these outliers should be filtered out. we did not follow this rule, since the factor scores were regarded as measures of the strength of the background process. also, the existence of such outliers calls for the application of a non­para­ metric simulation approach. fortunately, in this case the spatial outliers did not form any chain­like pattern which would have necessitated an indicator approach. the 200 equally probable stochastic realizations honoured well the statistical characters of the input set (figs. 7 and 8). the simulation result was accurate, although the simulated set showed slightly larger variability than that of the input. since a gaussian algorithm resulted in a unimodal distribution, the e­type grid could be accepted to show the average or general lateral distribu­ tion of the results of the migration process. the areal distributions of regions with high factor 1 scores of the e­type estimation roughly matched the surface projections of the known fields (figs. 1 and 9). the uncertainty of this rough matching was char­ acterized by the conditional variance of the probability distribu­ tions generated at the grid nodes. unfortunately, the highest un­ certainty values are concentrated in the larger area of the high factor 1 scores (fig. 11b). perhaps the heterogeneity of factor 1 scores in this area and its surrounding were the reason for the less accurate estimation results. the probability maps showed the possibility of locating such regions, where factor 1 scores are large in the sense of the defi­ nition given above. the results showed that the regions where this event had a large probability (in general the probability was > 0.7) could be clearly correlated with the subsurface hydrocarbon res­ ervoirs identified in seismic profiles (figs. 13–15). this correla­ tion produced a positive result even in the region where the un­ certainty was very high (heresznye anomaly in fig. 1, fig. 13 and fig. 14). the probability counterparts of the other known reser­ voirs on the map of the e­type estimation of factor 1 scores could be outlined with a significantly smaller uncertainty (fig. 9, fig. 11 and fig. 15). these results suggested that the research achieved its origi­ nal purpose: the connection between the known reservoirs and the rn and hc components of soil gases have been proven in the studied area. this verification seems to be more precise than those of the relevant literature, since it used not only the rn com­ ponents alone, but also the c2–c5 hydrocarbon components of soil gases. because of the positive verification, regions with a figure 15. correlation of the probability map of high factor 1 scores and the subsurface hydrocarbon fields along the third transect. g eo lo gi a c ro at ic a geologia croatica 69/2268 high probability of a positive anomaly of factor 1 scores, but without any reservoir counterparts, may be suggested as targets for surface hydrocarbon exploration. however, it can also be said that the presented modelling strategy demonstrated a correlation of the measured signal to re­ servoirs rather than more widespread petroleum system sources. acknowledgement this research was sponsored by the mol group (hungarian oil and gas company) in the frame of an r&d project. the authors would like to express their acknowledgement for permission to publish these results. also, many thanks for the reviewers for their valuable suggestions and comments. references armstrong, f.e. & heemstra, r.j. (1973): radiation halos and hydrocarbon reservoirs: a review. u.s. department of the interior, bureau of mines, 52 p. buttafuoco, g., tullarico, a. & falcone, g. (2007): mapping soil gas radon concentration: a comparative study of geostatistical methods. environ­ mental monitoring assesssment, 131, 135–151. doi: 10.1007/s10661-006-9463-7. castillo, p.i.c, townley, b.k., emery, x.f., puig, á.f. & deckart, k. (2015): soil gas geochemical exploration in covered terrains of northern chile: data processing techniques and interpretation of contrast anomalies.– geochemis­ try: exploration, environment, analysis, may 2015, v. 15, 222–233. doi: 10.1144/ geochem2014­283 child, d. (2006): the essentials of factor analysis. (3rd ed.). new york. continuum international publishing group. ciotoli, g., lombardi, s. & annunziatellis, a. (2007): geostatistical analy­ sis of soil gas data in a high seismic intermontane basin: fucino plain, central italy.– journal of geophysical research, vol. 112, b05407, doi:10.1029/ 2005jb004044, 2007 coleman, d.d., meents, w.f., liu, c.­l. & keogh, r.a. (1977): isotopic iden­ tification of leakage gas from underground storage reservoirsa progress report.– report 111, illinois state geological survey. 10 p. deutsch, c.v. (1989): declus: a fortran 77 program for determining optimum spatial declustering weights, computers & geosciences, 15/3, 325–332. doi: 10.1016/0098-3004(89)90043-5. deutsch, c.v. (1997): direct assessment of local accuracy and precision.– in: baafi, e.y. & schofield, n.a. (eds.): geostatistics wollongong. kluwer academic publishers, 115–125. deutsch, c.v. (2002): geostatistical reservoir modeling.– new york: oxford univer­ sity press, 376 p. deutsch, c.v. & journel, a.g. (1992) gslib: geostatistical software library and user’s guide.– new york: oxford university press, 340 p. dyck, w. & jonasson, i.r. (2000): in hale, m. (ed.): geochamical remote sens­ ing of the sub­surface. chapter 11. elsevier. geiger, j. (2012): some thoughts on the pre­and post­processing in sequential gaus­ sian simulation and their effects on reservoir characterization.– in: geiger, j., pál-molnár, e. & malvić, t. (eds.): new horizons in central european geomathematics, geostatistics and geoinformatics: selected studies of the 2011 croatian­hungarian geomathematical convent, mórahalom. szeged: geolitera, 17–35. ghagremani, d.t. (1985): radon prospecting for hydrocarbon: potential strategy for devonian shale gas in n.e. ohio; phd thesis, department of geological sci­ ences, case western reserve university, 259 p. gómez­hernández, j. & mohan srivastava, r. (1990): isim3d: an ansi­ c three­dimensional multiple indicator conditional simulation program, comput­ ers & geosciences, 16/4, 395–440. doi: 10.1016/0098-3004(90)90010-q. goovaerts, p. (1997): geostatistics for natural resources evaluation.– new york: oxford university press. 483 p. gotway, c.a. & rutherford, b.m. (1994): stochastic simulation for imaging spatial uncertainty: comparison and evaluation of available methods.– in: arm­ strong, m. & dowd, p.a. (eds.): geostatistical simulations proceedings of the geostatistical simulation workshop, fontainebleau, france, 27–28 may 1993. dordrecht: springer, 1–21. isaaks, e.h. (1990): the application of monte carlo methods to the analysis of spa­ tially correlated data.– phd thesis. stanford university, 213 p. isaaks, e.h. & srivastava, m.r. (1989): an introduction to applied geostatistics.– new york: oxford university press. 561 p. journel, a.g. (1983): nonparametric estimation of spatial distributions.– journal of the international association for mathematical geology, 15/3, 445–468. doi: 10.1007/bf01031292. journel, a.g. (1988): focusing on spatial connectivity of extreme­valued attributes: stochastic indicator models of reservoir heterogeneities.– society of petroleum engineers annual technical conference and exhibition: spe paper 1832. journel, a.g. (1994): modeling uncertainty: some conceptual thoughts.– in: dim­ itrakopoulous, r. (ed.): geostatistics for the next century. kluwer aca­ demic publishers, 30–43. doi: 10.1007/978­94­011­0824­9_5 jöreskog, k.g., klovan, j.e. & reyment, r.a. (1976): geological factor analysis.– methods in geomathematics 1, 180 p. elsevier scientific publishing co. isbn 0 444 41367 7 klusman, r.w. (1993): soil gas and related methods for natural resource explo­ ration. – john wiley, new york, 483 p. kristiansson. k. & malmqvist, l. (1982): evidence for nondiffusive transport of rn in the ground and a new physical model for the transport.– geophysics, 47, 1444–1452. landrum, j.h., ricers, d.m., maxwell, l.e. & fallgatter, w. (1989): a comparative hydrocarbon soil­gas study of the flathead valley and townsend val­ ley areas, montana.– journal of geochemical exploration, 34/3, 303–335. doi: 10.1016/0375-6742(89)90119-2li, y.l., yuan, g.j. & peng, d. (2006): discussion on geochemical exploration pre­ dicts the depth of oil reservoir (chinese).– wutan huatan jisuan jushu, 28/4, 367–371. maldonato, t.j. & campbell, g.e. (1992): an evaluation of total petroleum hydrocarbon data.– proceedings of the focus conference on eastern regional ground water issues. october 13­15, 1992. boston marriott newtown. newtown, massachusetts. http://info.ngwa.org/gwol/pdf/920157297.pdf malvic, t. (2008): kriging, cokriging or stochastical simulations, and the choice be­ tween deterministic or sequential approaches.– geologia croatia, 61/1, 37–47. doi: 10.4154/gc.2008.06 mcbratney, a.b. & webster, r. (1986): choosing functions for semi-variograms of soil properties and fitting them to sampling estimates.– journal of soil science, 37/4, 617–639. doi: 10.1111/j.1365-2389.1986.tb00392.x. mcdonald, r.p. (1985): factor analysis and related methods.– hillside, n. lawrence erlbaum associates, inc. 259 p. morse, j.g., rana, m.h. & morse, l. (1982): radon mapping as indicators of subsurface oil and gas.– oil gas j., 80, 227–246. morse, j.g. & zinke, r. (1995): the origin of radiometric anomalies in petroleum basins-a proposed mechanism.– oil and gas journal, 36–38., june 5, 1995. mucsi, l., geiger, j. & malvic, t. (2013): the advantages of using sequential stochastic simulations when mapping small­scale heterogeneities of the ground­ water level.– journal of environmental geography, 6/3–4, 39–47. doi: 10.2478/ jengeo-2013-0005 olivier, m.a. & kharyat, a.l. (1999): investigating the spatial variation of radon in soil geostatistically.– in: diaz, j, tynes, r., calcwell, d & ehlen, j. (eds): geocomputation cd­rom. isbn 0­9533477­1­0. http://www.geocompu­ tation.org/1999/095/gc_095.htm. palacios, d., fusella, e., avila y., salas, j., teixeira, d., fernández, g., salas, a., sajo­bohus, l., greaves, e., barros, h., bolívar, m. & regalado, j. (2013): radon measurements over a natural­gas contami­ nated aquifer. radiation measurements, vol. 50, 116–120. doi: 10.1016/j.rad­ meas.2012.10.016. patrick, r., frédéric, p., bharat, p.k., frédéric, g., mukunda, b. & soma, n.s. (2011): temporal signatures of advective versus diffusive radon transport at a geothermal zone in central nepal.– journal of environmental ra­ dioactivity, 102, 88–102. pirson, s.j. (1969): geological, geophysical, and geochemical modifications of sedi­ ments in the environment of oilfields.– smu symposium 1 on unconventional methods in exploration for petroleum and natural gas. 1969, dallas. saunders, d.f., burson, k.r., brown, j.j., & thompson, c.k. (1993): com­ bined geological and surface geochemical methods discovered agaritta and brady creek fields, concho county, tex.– aapg bull., vol. 77 no. 7 july 1993, 1221–1239. srivastava, m. (1994): the visualization of spatial uncertainty.– in: yarus, j. & chambers, r. (eds.): stochastic modeling and geostatistics.– aapg compu­ ter applications in geology, volume 3, 339–345. stevens, j.p. (2002): applied multivariate statistics for the social sciences (4th ed.).– hillsdale, ns: erlbaum, 641 p. tedesco, s.a. (1995): surface geochemistry in petroleum exploration.– springer, 206 p. doi: 10.1007/978-1-615-2660-5. isbn 9781-4613-6142-8. thurstone, l.l. (1931): the measurement of social attitudes.– journal of abnor­ mal and social psychology, 27, 249–269. doi: 10.1037/h0070363 várhegyi, a., gorjánácz, z. & horváth, zs. (2008): komplex radiometriai módszer alkalmazása a hazai szénhidrogén­kutatásban (application of a complex readimetriy method in hydrocarbon exploration, in hungarian).– bányászati és kohászati lapok, 141/3, 64–70. wrigley, m.j., stolpmann, h., al­jenaibi, m. & van laer, p. (2012): a direct hydrocarbon indicator method and results of a demonstration of capa­ bilities in abu dhabi.– aapg search and discovery article #40895 (2012). pos­ ted march 31, 2012. tukey, j.w. (1977): exploratory data analysis (addison­wesley series in behavioral science ­ quantitative methods).– 17th edn. reading, addison­wesley. www.geologia-croatica.hr abstract the triassic carbonate-hosted stratiform-stratabound base-metal deposits in the western balkan, nw bulgaria, have well defined regional geological and tectonic settings, style of mineralisation, mineralogical, geochemical and isotopic data. their genesis, however, remains controversial in the framework of plate tectonic models, and is not supported by comparative analysis of possible counterpart candidates within the nw tethyan domain. besides, the crucial missing information is the geochronology of ore mineralisation relative to the triassic carbonate host rocks. the article stresses the ambiguities due to the lack of mineralisation age dating, and emphasises the necessity for building a convincing plate tectonic model based on the relevant geodynamic setting. a prospective direction of research is the critical comparison with equivalent sediment-hosted base-metal deposits within the continental margin environments such as those in the alps and dinarides as well as others in the alpine-himalayan orogen and worldwide. keywords: siderite-base metal deposits, kremikovtsi-vratsa ore district, triassic metallogeny, moesian carbonate platform article history: received november 06, 2015 revised and accepted december 09, 2015 avaliable online february 29, 2016 1. introduction the triassic carbonate-hosted stratiform-stratabound basemetal deposits in the western balkan, nw bulgaria are mediumto small-sized deposits of lead, zinc, copper and silver located to the south of vratsa town. they also include the large iron-manganese-barium (+subeconomic lead-zinc) kremikovtsi deposit situated to the north of sofia, together comprising the kremikovtsi-vratsa ore district (popov, 1985) (fig. 1). these deposits share many similarities with the sedimenthosted base-metal deposits in the alps and dinarides (palinkaš et al., 2014 and references herein), the cracowsilesian district in poland (banks et al., 2003), iran (rajabi et al., 2013), and ireland (hnatyshin et al., 2015), etc. the triassic sediment-hosted base-metal deposits in the alps and dinarides formed within the adriatic-dinaridic carbonate platform – a passive continental margin of gondwana (palinkaš et al., 2014). the triassic carbonate-hosted base-metal deposits in the western balkan (bulgaria) formed within the balkan terrain – a precambriancambrian ophiolite-island arc assemblage, unconformably overlain by a palaeozoic sedimentary sequence. this terrain was accreted to the palaeozoic basement of the moesian platform (located to the northward) in upper carboniferous time. basements of the balkan and the moesian terrains are of gondwana origin (haydoutov & yanev, 1997). thus, the hercynian orogonesis resulted in closure of the palaeo-tethys and accretion of gondwana and the eurasian plate (dabovski & zagorchev, 2009). the location of ancient and old mine workings are known for almost all deposits in the western balkan. it is believed that the thracians were the first to start mining, followed by the romans and then the saxons. during the ottoman rule, min65-73 4 figs. 2 pls. doi: 10.4154/gc.2016.05 figure 1. location of the kremikovtsi-vratsa ore district in the bulgarian early mesozoic tectonic setting (a) from damyanov (1995) and distribution of the carbonate triassic formation in the nw bulgaria (b) from zagorchev & budurov (2009). plate tectonic aspects of the triassic carbonate-hosted stratiform-stratabound base-metal deposits in the western balkan, nw bulgaria irina marinova* and zhelyazko damyanov bulgarian academy of sciences, institute of mineralogy and crystallography, acad. g. bonchev str., block 107, 1113 sofia, bulgaria (*corresponding author: irimari@gmail.com) vol. 69/1 66 ers hired by the republik of dubrovnik, after primitive melting, carried the metal to dubrovnik proper. in 1902, the modern mining industry in the vratsa ore district started with the opening of the plakalnitsa mine. the mine had been operating for around 90 years until 1998, when the last mines were closed (petrov et al., 2011). unlike the kremikovtsi depo sit which has been known since the end of the 19th century. smallscale production began in 1913. the modern production started in 1963 and continued until the early 21st century. the deposits in the kremikovtsi-vratsa ore district were intensively explored and studied over a long time with the onset in the 1960-1990s of the 20th century. comprehensive researchers of the vratsa ore region and the biggest sedmochislenitsi deposit are atanasov (1972) and minchevastefanova (1988) with their comprehensive reviews concerning the deposit mineralogy and geochemistry. tectonics of the ore deposits were studied by kalaydziev (1977, 1982), kalaydziev & popova (1981) and by chernev (1993). the kremikovtsi deposit was studied by many researchers (review in kanourkov, 1988) among whom the studies of ratiev (1977), kalaydziev et al. (1982), kanourkov (1988), popov (1989), bakardziev & popov (1995), and damyanov (1993) are more comprehensive. past research constrained the general features of the deposits including the geological setting, tectonics, style of mineralisation, ore and gang mineralisation and geochemistry. some issues, however, have remained unresolved. the dating of ores is based only on pb isotope data, which remains controversial. the sources of metals and fluids are poorly defined, and the data on the geodynamic setting of the deposits needs updating. hence, the genetic models created are very different and often contradictory. the paper reviews the published data on the triassic carbonate-hosted stratiform-stratabound base-metal deposits in the western balkan, nw bulgaria concerning their geology and mineralogy. it illustrates the principal ore textures, briefing the main ideas on their origin, and outlines directions for future research. the primary goal is to clarify and confirm the relevant geodynamic setting in relation to the other triassic sediment-hosted base-metal deposits within the continental margin environment, likewise equivalent deposits in alps and dinarides as well as the other similar deposits in the alpinehimalayan orogen and worldwide. 2. geological framework the western balkan is part of the balkan orogenic zone. to the east the balkan zone comprises the central balkan and eastern balkan units. the western balkan is composed of neoproterozoic-cambrian basement, poorly preserved palaeozoic mantle (mainly permian variegated sediments) and mesozoic cover of triassic clastic and platform carbonate rocks, lower to middle jurassic continental and shallow marine sediments overlain by upper jurassic – lower cretaceous sediments. in the late cretaceous the western balkan fall in compression mode as in the middle eocene it was thrust over the edge of the moessian platform. during thrusting, the northern periphery of the western balkan was the primary zone of tectonic deformation (dabovski & zagorchev, 2009). the deposits in the kremikovtsi-vratsa ore district are mainly hosted by the lower to middle triassic limestones, dolomitized limestones and dolostones in areas of their synclinal foldings. base-metal mineralisations are also known in the lower and middle jurassic carbonate-terrigenous rocks (e.g. the breze iron deposit in the western balkan, kanourkov, 1988) and in the basement rocks (vratsa ore district, kanourkov, 1988; kremikovtsi deposit, damyanov, 1996, 1998) but of smaller extent. the base-metal mineralisations in the western balkan crop out largely along the iskar river where deeply incised valley display the thick triassic sequence. the iskar riverbed is at 300-400 m above sea level; the peaks in the vratsa balkan are high, at about 1300-1600 m a.s.l., and the relief is strongly incised. in the western balkan the triassic carbonate rocks do not occupy a large area because denudation after the triassic eroded most of the formation exposed in positive elevation structures (fig. 1). the triassic section in boreholes in the moesian platform exceeds 1 km (vaptsarova et al., 1979). the area in the western balkan which hosts stratiformstratabound base-metal mineralisations is a part of the large berkovitsa anticline which includes wide and flat second-order synclines and anticlines. it developed between the triassicjurassic and the upper cretaceous (yovchev, 1961). its palaeozoic core crops out along the iskar river and comprises hercynian intrusive rocks (granodiorites and granites). the latter are overlain discordantly by upper carboniferous quartzites, sandstones and coal-bearing argillites. passing upwards, permian terrigenous-volcanogenic rocks crop out. the triassic sequence begins with a regional discordance – the lower triassic monogenic conglomerates and monomictic (quartz) to oligomictic sandstones overlie a variegated basement of precambrian rocks, palaeozoic low-grade metamorphic and magmatic rocks or permian red beds (fig. 2). the exact age of the triassic transgression is not known. the triassic system in bulgaria lacks discordances or discontinuities. a regional unconformity at the end of the triassic and the beginning of the jurassic is very well recorded as most tectonic units are related to the early cimmerian orogenic phase (bonchev, 1940). the triassic formations developed after the hercynian orogeny, following denudation of the expressive topography, deposition of the lower permian molasse type sediments and the late permian. differential subsidence, accompanied by embryonic rifting (the chiren rift in the west balkan terrain) led to a marine transgression at the end of the early triassic and a marine regime in the middle triassic time with the foundation of the carbonate platform. at the end of the triassic, activation of the late cimmerian orogenic phase began, followed by compression and weak folding which resulted in a gradual regression, leading to massive drainage over the entire bulgarian territory. this regression was in contrast to development in the dinarides, albanides and helenides where mesozoic marine sedimentation was continued without interruption into the neozoic (zagorchev & dabovski, 2009). triassic carbonate sedimentation was accompanied by magmatism, established to the north of the vratsa ore district and marinova & damyanov: plate tectonic aspects of the triassic carbonate-hosted stratiform-stratabound base-metal deposits... 67 within the kremikovtsi region (chemberski & vapcarova, 1979; damyanov, 1993, 1996). in the vratsa district, boreholes intersected lava flows of massive or amygdaloidal basalts, trachybasalts, and trachytes up to 40 m thick. the lava flows alternate with tuffs and epiclastites, while the volcaniclastic products in addition alternate with limestones and dolostones. this volcano-sedimentary alternation has a maximum thickness up to 160-200 m. the volcanic activity began in the olenekian (t1) and continued to the lower-middle? carnian (t3 1) with the most pronounced intensity in the middle triassic. the volcanism was high-potassium alkaline to transitional intraplate, related to rifting (cortesogno et al., 2004). the triassic magmatism in the kremikovtsi district is represented by tuffs but it has been poorly studied. the ore deposits and occurrences in the vratsa ore district are arranged along three regional, steep, normal faults of predominant nw to e-w and wsw strike and length up to 700800 m, which are in order from the north to the south the: plakalnitsa, pop-sokoletski and izdremets faults (fig. 2). yovchev (1961) thought these faults were conduits for fluids from the palaeozoic to the oligocene and were responsible for the formation of the stratiform-stratabound base-metal deposits. mincheva-stefanova (1988), popov (1989) and chernev (1993), considered that the locus of the basemetal mineralisation is placed at the intersections of these faults with other, less-pronounced ones, of northeastern strike. these tectonic relationships derived bias which attributed the stratiform-stratabound base-metal deposits in the western balkan to the post lower cretaceous by the latter authors. the kremikovtsi deposit is located within the western balkan zone next to the srednogorie zone, located to the south. figure 2. geological map of the vratsa ore district (after tronkov & mincheva-stefanova, from mincheva-stefanova, 1988, with simplification): 1 – palaeozoic rocks, 2, 3, 4 – lower, middle and upper triassic sediments, respectively, 5 – jurassic sediments, 6a – cretaceous sediments, 6b – quaternary sediments, 7 – fault, certain by continuous line, uncertain by dashed line, 8 – thrust or klippe, 9 – flexure, 10 – line of cross-section, 11 – base-metal deposit, in bold major one, numbered, 12 – barite vein deposits, 13 – number of ore zone (i – vratsa, ii – pop-sokolets, iii – izdremets), 14 – number of deposit: in the vratsa ore zone – 1sedmochislenitsi; 2 – plakalnitsa; in the popsokolets ore zone – 3 – majo, 4 – balichin preslap, 5 – gerana; in the izdremets ore zone – 6 – venetsa, 7 – lakatnik, 8 – hristo botev, 9 – bakara, 10 – zapachitsa, 11 – rakov dol, 12 – perovo. vol. 69/1 68 the ore bodies are hosted by the allochthone of the kremikovtsi thrust within the triassic dolomitized limestones (fig. 3). the allochthone base facies are palaeozoic phyllites, while upper cretaceous sediments succeed in the uppermost section. sediments of lower and upper triassic, jurassic and lower cretaceous age are placed along the thrust plane. these facts determine the age of thrusting as illyrian (kanourkov, 1988), and imply that the main stratiform ore bodies were already formed during the triassic, contemporaneously with the triassic host carbonate rocks (damyanov, 1996). then, the deposit was translated to the nw over a 1.5 km distance during the thrust. 3. mineral composition of the base-metal mineralisations in the vratsa ore district, mincheva-stefanova (1988) distinguished two base-metal ore types: (1) the lead-zinc and (2) the lead-copper (pb-cu-ag ± bi). based on their relationships, the author considered the two types as having been formed in the same temporal order. (1) the lead-zinc type comprises the following mineral parageneses: (i) pre-ore dolomitization; (ii) pyrite; (iii) dolomite-sphalerite; (iv) galena-sphalerite; (v) galena; (vi) calcite; (vii) dolomite, and (viii) barite-dolomite. (2) the lead-copper (pb-cu-ag±bi) type bears (i) barite; (ii) tenantitebornite-chalcopyrite; (iii) galena; (iv, v) two silver parageneses, and (vi) late calcite paragenesis. the (iv,v) silver-rich parageneses contain various silver sulfosalts which predominate as well as silver sulfide, rare native silver, cinnabar and balkanite (cu9ag5hgs8). mineral balkanite was found for the first time in the sedmochislenitsi deposit and was named after the balkan mt., the place of recognition, by atanasov (1972). the formation of pre-ore dolomitization occurred at 140120°c, tenantite-bornite-chalcopyrite mineralisation around 200°c, and the rest of parageneses formed at lower temperature (100-70°c) (mincheva-stefanova, 1988). the great number of parageneses suggests a prolonged time of mineralisation formation. chernev (1993) came to the same conclusion implying tectonic data. the kremikovtsi deposit contains the following primary ore types with the respective economic commodities: siderite, haematite, barite and galena. the gangue minerals in the siderite ore are microquartz, berthierine, chamosite, ferroan dolomite and ankerite. the principal gangue minerals in the haematite ore are microquartz and calcite (damyanov, 1996, 1998). the barite ore contains quartz, calcite, ferroan dolomite and ankerite, while the lead ore comprises dolomite in addition. the siderite and haematite ore bodies are mainly massive and finely banded. the barite bodies have both a massive and vein appearance. the galena ore displays disseminated and replacement textures. 4. styles of base-metal mineralization and ore textures 4.1. vratsa ore district the base-metal mineralisation in the vratsa ore district is mainly stratiform and lens-shaped with a length commonly of 400500 m and thickness about 10 m (fig. 4). impregnations of the host rocks are very common and stockwork bodies also occur (yovchev, 1961; kalaydziev et al., 1982; mincheva-stefanova, 1988). the dip of stratiform ore bodies is consistent with the host sediments (fig. 4). vein morphology is very rare. kalaydziev (1982) estimated that in the sedmochislenitsi deposit around 80% of the ore bodies are hosted by dolostones and around 20% in dolomitized limestones. he related this fact to the increased fracturing of the dolomitic rocks. the triassic limestones are micritic (pl. 1a) and the dolostones are formed by the diagenetic dolomitization of limestones, and both appear dark grey to black. the diagenetic dolomitization of limestones was even determined in the earliest studies (references in mincheva-stefanova, 1988). the figure 3. geological map of the kremikovtsi deposit and cross-section (without pliocene and quaternary sedimentary cover) (from kanourkov, 1988): 1 – upper cretaceous?: basaltic trachyandesites and trachyandesites; 2 – senonian: marls and marly limestones; 3 – tithonian-berriasian flysch: sandstones, siltstones, marls and marly limestones; 4 – hettangian-kimmeridgian: sandstones, sandy and marly limestones, marls, and limestones; 5 – early-middle triassic: limestones and dolomitized limestones; 6 – early triassic: sandstones; 7 permian: volcanogenic and terrigenous rocks; 8 – early carboniferous: alkaline syenites; 9 – ordovician and silurian: limestones and phyllites; 10 – rocks of uncertain age; 11 – fault; 12 – thrust; 13 contour of the open pit in 1984; 14 ore body; 15 – faults: 1 – golyama rakovitsa, 2 – negushevo, 3 – bukovokremikovtsi, 4 – kremikovtsi thrust, 5 – ludokamenski, 6 – uitimarski, 7 – potopski, 8 – bratinski, 9 – proboinishki. marinova & damyanov: plate tectonic aspects of the triassic carbonate-hosted stratiform-stratabound base-metal deposits... 69 triassic carbonate rocks are dense, of massive texture. sulfides occur as replacements, open-space fillings (crack and vug fillings), colloform masses, and disseminations (pl. 1). in the vratsa ore district, chernev (1993) defined three types of ore bodies in mesozoic carbonate rocks disregarding the ore composition: (i) ore bodies in the lithology favourable for ore precipitation, (ii) ore bodies in the intersections of folds of different strikes, and (iii) ore bodies with upper or lower boundaries unconformable to the bedding. the first type is predominant in the vratsa district. the author underlined that this type does not display a relationship to faults and looks like a syngenetic one. the formation of the second type is favoured by the high degree of fracturing due to interference of cleavages in the intersections of folds of different strikes, and to the development of extensional fracturing along the bedding. in other cases, the fold cleavage does not display a relationship with the sulfide mineralisation. the third type is a result of the combination of favourable lithology and brecciation/or fracturing. popov et al. (1989) counted the density of fractures in the host dolostones in the plakalnitsa deposit and yielded 200-300 per m3, while in the host limestones their number was 20-30 per m3, evidencing the importance of fracturing for ore deposition. several authors (atanasov, 1973; kalaydziev & popova, 1981; mincheva-stefanova, 1988; chernev, 1993) paid attention to the relationship of some deposits to local deflexion of the regional plakalnitsa and pop-sokolets faults. such deflexions form extensional jogs and contain ores. atanasov (1973) pointed out that the thickness of ore bodies increases when approaching some steep faults forming stocklike thickening of highly brecciated and mineralised host rocks. kalaydziev (1982) demonstrated by geological cross-sections that steep normal faults either transposed stratiform bodies or have no effect on their spatial position. the afore-mentioned authors agree that openings along the bedding were favourable for ore deposition. marl intercalations and thin-bedded dolostone packets were considered to be a screen for the ore fluids (kalaydziev, 1982), while organic matter was a chemical reducer (mincheva-stefanova, 1988). another structural factor is the intense fracturing of sediments near the regional faults. these areas contain sulfide mineralisation (chernev, 1993). the micritic texture predetermines the main fine-grained massive texture of the ores. the replacement origin of the massive texture is evidenced by relics of the host carbonate grains inside the sulfide (pl. 1a–c). a second distribution type has the colloform texture of sphalerite and pyrite (pl. 1e–f). the individual crystals are very fine – commonly several microns. usually, the individual minerals are ultimately mutually intergrown. the presence of both sparry dolomite and sulfides in dolomitized micritic limestone indicates the simultaneous deposition of sparry dolomite and sulfides (pl. 1d). in places, colloform pyrite consists of minute globular grains suggesting aggregation of colloidal particles (pl. 1g). later carbonates have corroded the base-metal mineralisation (pl. 1h). 4.2. kremikovtsi deposit in the kremikovtsi deposit the siderite, haematite and barite bodies in the triassic carbonate rocks are presented in lenses and beds, while the lead-rich bodies have pipe-like and lens morphologies. thus, the ore bodies are stratiform and bound to the triassic carbonates. the mineralisation in the palaeozoic basement is cross-cutting, hosted by faults of the feeder zone (damyanov, 1996, 1998). the siderite ore is mainly composed of fine-grained mgmn siderite with massive texture rarely intercalated by fine clayey bands enriched in organic matter (pl. 2a). siderite is associated with microquartz cementing the carbonate aggregates (pl. 2b) and fineto medium-grained barite with sulfides and authigenic phyllosilicates forming veinlets, nests and impregnations (pl. 2 c–f). the barite mineralisation is widespread in the iron formations of the kremikovtsi deposit (pl. 2 c–g) and is one of the world’s largest hosts of barite concentrations and reserves. coarse-grained tabular barite crystals form the main lenticular or subvertical veined barite ore bodies. haematite ore is composed of fine-grained or tabular to flaky haematite (specularite) with a massive texture associated occasionally with barite veinlets and nests and ca-mg siderite cement (pl. 2 g, h). although significant quantities of pb and ag (+ cu, zn, hg, sb) have accumulated in the kremikovtsi deposit the sulfide mineralisation is disseminated, low-grade and still uneconomic. figure 4. cross-section the sedmochislenitsi syncline and deposit (from mincheva-stefanova, 1988): 1 – carboniferous sediments, 2 – lower triassic sediments, 3 – anisian limestones, 4 – anisian dolostones, 5 – ladinian sediments, 6 – upper triassic sediments, 7 – mylonite, 8 – faults, 9 – ore bodies. vol. 69/1 70 plate 1 photomicrographs of base-metal mineralisation from the sedmochislenitsi deposit, the biggest deposit in the vratsa ore district (a-d – in transmitted light, e-h – in reflected light): a – micritic dolomitized limestone with sulfides along micro-cracks and as vug filling, xpl; b – replacement of micritic dolomitized limestone by sulfide with inclusions of re-crystallized carbonate within the sulfide, ppl; c – rhythmic replacement of dolomite by sulfide in micritic limestone, xpl; d – sparry dolomite in micritic limestone. the interstices of dolomite crystals are filled with sulfides (black), xpl; e-f – colloform sphalerite, pyrite and carbonate in micritic dolomitized limestone (e in xpl, f – in ppl); g – colloform pyrite aggregate built up of minute globular grains in micritic limestone, xpl; h – bornite-chalcopyrite-galena assemblage corroded by late sparry carbonate, xpl; inset in ppl. scale bar: in a, b, c, g, h – 1 mm; in d, e, f – 0.5 mm. abbr.: ppl plane polarized light, xpl – cross polarized light, micr – micritic, sp – sphalerite, dol – dolomite, cb – carbonate mineral, py – pyrite, bn – bornite, gn – galena, ccp – chalcopyrite. marinova & damyanov: plate tectonic aspects of the triassic carbonate-hosted stratiform-stratabound base-metal deposits... 71 plate 2 photomicrographs of primary ore types in the kremikovtsi carbonate-hosted iron-barite-sulfide deposit (b, d, g, h – sem; c, f – reflected light): a – massive siderite intercalated with fine clayey bands enriched in organic matter, outcrop; b – massive siderite with microquartz cement in interstices and framboidal pyrite; c – massive medium-grained siderite associated with barite, quartz, framboidal pyrite and chalcopyrite; d – barite nest in massive siderite with microquartz cementing carbonate grains; e – veinlets and nests of coarse-grained barite associated with base-metal sulfides in hydrothermally re-crystallized sparry siderite; f – massive medium-grained siderite associated with tabular barite impregnations and quartz; g – barite veinlet in massive flaky hematite (specularite); h – massive fine-grained and tabular hematite with siderite cement. scale bar: b30 µm; d – 50 µm; c, f – 250 µm; g-h – 10 µm. abbr.: sid – siderite, bar – barite, q – quartz, pyr – pyrite, chp – chalcopyrite, sulf – sulfides. vol. 69/1 72 5. age of mineralisation and sulfur isotopes attempts to date the base-metal mineralisations in the vratsa ore district were made using the u/pb geochronology of galena. the results fell into two groups: the first with a model age of 240-270 ma (permian-triassic), older than the host triassic carbonates; the second with the late lower cretaceous model age of 120 ma (review in mincheva-stefanova, 1988). lead isotopes of the main ore stage in the kremikovtsi deposit gave a palaeozoic model age (~310 ma, middle/upper carboniferous; amov et al., 1977) with grouping into two subsets: “younger pb” in lower beds and “older pb” in upper beds. this fact was explained by damyanov (1995) applying intense mixing of ore fluids in a two-stage hydrothermal system: the earlier one, related to hydrothermal sedimentation on the sea floor followed by diagenesis, and a later one of epigenetic origin, when boiled fluid in feeder zones deposited stockwork and vein barite/base-metal mineralisations in the host triassic carbonate rocks and the palaeozoic basement as well. the isotopic composition of sulfide (pyrite, galena, and sphalerite) from the vratsa ore district (dimitrov et al., 1986) is similar to that from the mississippi valley stratiform deposits (ohmoto & rye, 1979). the range of δ34s, ‰ for pyrite is from -27 to +15, for galena from -24 to +14, and for sphalerite from -15 to -4.5, as the average δ34s, ‰ for each sulfide has a negative value. the high scattering of δ34s values was explained with different sulfur sources, leaching of sulfur from host rocks and biogenic reduction of the sulfate anion (dimitrov et al., 1986). these authors established the lowermost radiogenic lead as galena in the vratsa ore district compared to other lead-zinc and copper deposits in bulgaria. 6. genetic models styles of mineralisation, stratiform and stratabound, and those cross-cutting the triassic strata, as well as three consequent tectonic phases, and the controversial u/pb ages of galena, have led to a great variety of genetic models: telethermal, synsedimentary, epigenetic hydrothermal, hydrothermal-metasomatic, sedimentary-hydrothermal, sedimentaryexhalative (review in mincheva-stefanova, 1988; damyanov, 1995). in addition, the late cretaceous magmatism, (the only evidence of igneous activity in the area till recently), linked the formation of the deposits with the magmatism as both the driving force and source of fluids. more recently, the finding of triassic magmatic rocks in boreholes to the north of the kremikovtsi-vratsa ore district has changed the views of researchers. taking into account the presence of triassic basaltic magmatism in the area, damyanov (1995) presented the concept about the triassic rift origin of the stratiform-stratabound deposits in the west balkan. the triassic rift in bulgaria is an embryonic one because of the very constrained spatial distribution of the basaltic magmatism. on the other hand, palinkaš et al. (2014) consider the triassic sedex and mississippi valley type (mvt) deposits in the alps and dinarides as a result of advanced rifting. as a corollary, the triassic deposits in the alps and dinarides, and those in the western balkan, display a common geodynamic setting – triassic rifting. these fruitful ideas need further confirmation through the united efforts of geologists from different countries. 7. concluding remarks in conclusion, it should be stressed that the timing of the triassic carbonate-hosted base-metal mineralisations in the western balkan is unknown. we have to expect ages ranging from the triassic to post-early cretaceous bearing in mind the presence of different mineralisation styles and the protracted tectonic reworking of the triassic host rocks, including the early and late cimmerian tectonic phases and the austrian phase. the recent advantages of isotopic methods for dating of sulfides like the os/re, rb/sr, and sm/nd geochronology would be very useful for solving the existing problems. the experience with os/re dating of pyrite from the irish pb-zn sediment-hosted deposits (hnatyshin et al., 2015), rb/sr dating of sphalerite from australian mvt deposits (christensen et al., 1995), and sm/nd dating of pb-zn ore (jiang et al., 2000) are successful examples suggesting one direction for future research. another isotopic ratio, e.g. of o, h and c would elucidate the poorly constrained sources of metals and fluids. acknowledgment the national museum “earth and man”, sofia is greatly acknowledged for the hand specimens from the sedmocislenitsi deposit. the authors express their gratitude to the reviewers l. palinkaš and s. palinkaš for the manuscript improvements and language handling. references amov, b., bogdanov, b. & baldzieva, c. (1977): lead isotope composition and some questions about the origin and age of mineralizations in southern bulgari.– in: problems of ore deposits formation, vth symposium, varna, 2, 13−25. atanasov, v. (1972): mineralogy of the copper-lead-zinc stratiform sedmochislenitsi deposit, bulgaria.– phd thesis, institute of geology and geophysics, siberian branch of the russian academy of sciences, novosibirsk, 398 p. (in russian). atanasov, v. (1973): on the structure and natural boundaries of the sedmochislenitsi copper-lead-zinc deposit, western stara planina mt.– annual higher inst. min. geol., sofia, 19/2, 1−17 (in bulgarian, with english summary). atanasov, v. & kirov, g. (1973): balkanite, cu9ag5hgs8, a new mineral from the sedmochislenitsi mine, bulgaria.– am. mineralogist, 58, 11−15. bakardziev, s. & popov, p. (1995): geological-structural features of the deposit.− in: the kremikovtsi barite-iron deposit and the jurassic system in the region, guidebook, mining and geol. univ., sofia, 2−4, 10−15 (in bulgarian). banks, d., schnider, j., kucha, h. & keppens, e. (2003): carbonatehosted zn-pb deposits in upper silesia, poland: origin and evolution of mineralizing fluids and constraints on genetic models.− econ. geol., 98/5, 911−932. bonchev, e. (1940): alpine tectonic manifestations in bulgaria.− rev. bulgarian geol. soc., 12/3, 155−227 (in bulgarian). chemberski, h. & vapcarova, a. (1979): the triassic system in north bulgaria. i. stratigraphic principles.– geologica balcanica, 9/1, 67−108 (in russian, abstract in english). chernev, e. (1993): formation conditions of the alpine base-metal ore fields in the vratsa ore unit.− ph.d. thesis, sofia (in bulgarian). christensen, j., halliday, a., vearncombe, j. & kesler, s. (1995): testing models of large-scale fluid flow using direct dating of sulfides; rb-sr evidence for early dewatering and formation of mississippi marinova & damyanov: plate tectonic aspects of the triassic carbonate-hosted stratiform-stratabound base-metal deposits... 73 valley-type deposits, canning basin, australia.¬ econ. geol., 90/4, 877−884. doi: 10.2113/gsecongeo.90.4.877 cortesogno, l., gaggero, l. & yanev, s. (2007): anorogenic volcanism in the triassic sequences at the boundary of the moesian plate.− geodin. acta, 17/1, 55−69. doi: 10.3166/ga.17.55-69 dabovski, c. & zagorchev, i. (2009): alpine tectonic division of bulgaria.− in: zagorchev, i., dabovski, c. & nikolov, t. (eds): geology of bulgaria, vol. ii., part 5. mesozoic geology, sofia, prof. marin drinov publ. house, 30−37 (in bulgarian). damyanov, z. (1993): mineralogical features and genesis of the sideritebearing ores from the kremikovtsi deposit.− unpubl. ph.d. thesis, sofia. damyanov, z. (1995): triassic metallogenesis in the west balkan.− compt. rend. acad. bulg. sci., 48/11−12, 75−78. damyanov, z. (1996): genesis of the kremikovtsi deposit and metallogenic perspectives of the sredec iron ore region.− geologica balc., 26/4, 3−24. damyanov, z. (1998): ore petrology, whole-rock chemistry and zoning of the kremikovtsi carbonate-hosted sedimentary exhalative iron(+mn)-barite-sulfide deposit, western balkan, bulgaria.− n. jb. miner. abh., 174/1, 1−42. dimitrov, r., bogdanov, k., breskovska, v., mankov, s., arevadze, d. & jaroshevich, v. (1986): isotopic composition of sulfur from lead-zinc and copper ore deposits in bulgaria.− ore-form. processes and mineral dep., 25, 3−21 (in bulgarian, with english summary). haydoutov, i. & yanev, s. (1997): the protomoesian microcontinent of the balkan peninsula – a peri-gondwanaland piece.− tectonophysics, 272, 303−313. hnatyshin, d., wilkinson, j. & gleeson, s. (2015): re-os dating of pyrite confirms on early diagenetic onset and extended duration of mineralization in the irish zn-pb ore field.− geology, 43/2, 143−146. jiang, s., slack, j. & palmer, m. (2000): sm-nd dating of the giant sullivan pb-zn-ag deposit, british colombia.− geology, 28/8, 751−754. kalaydziev, s. (1977): new data on the structural and lithological factors influenced the location of base-metal mineralisations in the izdremets deposit, western stara planina.− ore-form. processes and mineral dep., 6, 3−16 (in bulgarian, with english summary). kalaydziev, s. (1982): new data on the structural peculiarities of the kremikovtsi ore field.− rev. bulgarian geol. soc., 43/2, 159−171 (in bulgarian). kalaydziev, s. & popova, p. (1981): structural features of the stratiform plakalnitsa deposit, western stara planina.− rev. bulgarian geol. soc., 42,/1, 17−29 (in bulgarian, with english summary). kalaydziev, s., lilov, c., valchev, v. & toshkov, a. (1982): new data on the morphological peculiarities of ore bodies in the sedmochislenitsi polymetallic deposit.− ore-form. processes and mineral dep., 17, 34−49 (in bulgarian, with english summary). kanourkov, g. (1988): the iron deposits in bulgaria.− technika, sofia, 282 (in bulgarian, with english summary). mincheva-stefanova, y. (1988): sediment-hosted polymetallic deposits in the western stara planina mt.− in: dimitrov, r. (ed.): the lead-zinc deposits in bulgaria, technika, sofia, 175-192 (in bulgarian). ohmoto, h. & rye, o. (1979): isotopes of sulfur and carbon.− in: barnes, h. (ed.): geochemistry of hydrothermal ore deposits, wiley, new york, 509−567. palinkaš, l., damyanov, z., borojević, s., strimic, s. & marinova, i. (2014): divergent rifting separation of adriatic-dinaric and moesian carbonate platforms witnessed by triassic mvt and sedex deposits, metallogenic approach.− proc. xx cbga congress, tirana, 24-26 sept. 2014, 2, 428−431. petrov, p., atanasova, s., nesheva, l. & kunov, a. (2011): preserved mineral diversity of stratabound deposits, western stara planina mt., bulgaria.− proc. vith intern. symp. “mineral diversity. research and preservation”, 7−10 oct. 2011, sofia, 223−232. popov, p. (1985): geological-tectonic and structural conditions of the formation of stratiform deposits in the western balkan metallogenic zone.− geol. ore dep., 27/6, 26−34 (in russian). popov, p. (1989): tectonic setting and structure of the upper cretaceous mineralisations in the banat-srednogorie and the west balkan metallogenic zones (bulgaria).− d.sc. thesis, sofia (in bulgarian). popov, p., chernev, e. & antonov, m. (1989): on the structure of plakalnitsa ore field.− annual higher inst. min. geol., sofia, 25/2, 43−60 (in bulgarian, with english summary). rajabi, a., rastad, e. & canet, c. (2013): metallogeny of permian-triassic carbonate-hosted zn-pb and f deposits of iran. a review for future mineral exploration.− australian j. earth sci., 60/2, 197−216. ratiev, l. (1977): on the pipe-like depositions of lead in the kremikovtsi iron deposit.− in: problems of ore formation, bas publ. house, sofia, 541−546 (in bulgarian). vaptsarova, a., chemberski, h. & nikolova, l. (1979): le trias dans la bulgarie du nord. iv. les sediments carbonates de la formation de dojrenci dans la partie central de la bulgarie du nord.− geologica balc., 13/2, 75−88. yovchev, y. (1961): mineral resources of bulgaria. base metals. sofia, tehnika, 132 p. zagorchev, i. & budurov, k. (2009): triassic geology.− in: zagorchev, i., dabovski, c. & nikolov, t. (eds.): geology of bulgaria, vol. ii., part 5. mesozoic geology, sofia. prof. marin drinov publ. house, 40−102 (in bulgarian). zagorchev, i. & dabovski, c. (2009): mesozoic evolution.− in: zagorchev, i., dabovski, c. & nikolov, t. (eds.): geology of bulgaria, vol. ii., part 5. mesozoic geology, sofia, prof. marin drinov publ. house, 21−29 (in bulgarian). 2016 | 69/3 | 325–336 | 9 figs. | www.geologia-croatica journal of the croatian geological survey and the croatian geological society 1. introduction the greatest proportion of the literature dealing with the assessment (qualitative and quantitative) of geodiversity refer to rural and mountainous areas that are uninhabited or sparsely populated and where the human impact on geological diversity is weaker (stepišnik & repe, 2015; manosso & nóbrega, 2015; silva et al., 2013, 2014; pereira et al., 2013; pellitero et al., 2011; hjort & lout, 2010; benito-calvo et al., 2009; serrano & ruiz-flaño, 2007; serrano & ruizflaño, 2009; serrano et al., 2009; kozlowski, 2004; alexandrowicz & kozlowski, 1999, etc). in contrast, urban areas are often densely populated and the pressure on geodiversity is extremely high. urbanization and the influx of population to the cities cause territorial expansion and greater use of georesources. geodiversity in unpopulated areas is considered in the context of its impact on other natural components while in urban conditions its effect is more considered in the context of the urban development. in rural areas, it is a prerequisite for the development of biodiversity and it affects the variety of landscape diversity. alternatively, in urban areas, its significance is mainly to meet the needs of man, while other values are of less importance. for the evaluation of geodiversity of urban areas it is important to study the characteristics resulting from natural processes without human impacts, and also to determine the relation of geodiversity with the development of the city. natural characteristics (geological, geomorphological, hydrological and pedological) affect the physical development and the distribution of the city area, but they also affect its economic, cultural and social development. unlike the uninhabited areas, prominent constituents of geodiversity of urban areas also include anthropogenic application of the geodiversity index for the assessment of geodiversity in urban areas: an example of the belgrade city area, serbia marina m. ilić1,*, sanja stojković2, ljupko rundić3, jelena ćalić4 and dejan sandić2 1 phd student,university of belgrade, studenski trg 1, belgrade, serbia; (corresponding author: mrnilic@yahoo.com) 2 university of belgrade, faculty of geography, studenski trg 3/3, belgrade, serbia 3 university of belgrade, faculty of mining and geology, đušina 7, belgrade, serbia 4 geographical institute „jovan cvijić” of the serbian academy of sciences and arts, đure jakšića 9, belgrade, serbia doi: 10.4154/gc.2016.27 abstract considering the fact that urbanization is one of the most serious threats to geodiversity, it is important that this issue is taken into account in spatial development plans and georesource management strategies in urban areas. this paper presents the application of a geodiversity evaluation method by using the geodiversity index, based on the quantity of abiotic elements and relief roughness within a spatial unit. geodiversity assessment, usually used for remote, protected and sparsely populated natural areas, is now carried out in an urban environment – the city of belgrade, capital of serbia, with a population of about 1.7 million inhabitants and very strong urbanization in the last few decades. the area of 3227 km2 is processed with the spatial resolution of 1 x 1 km. the acquired results from the geodiversity index are analyzed in the context of sustainable use of georesources and the threats to which geodiversity is exposed due to the territorial expansion of the city. the mapping of specific categories of geodiversity on the basis of quantitative assessment with the use of geographic information systems can help decision makers and managers to take further steps that would reduce threats and protect the natural value of belgrade. article history: manuscript received february 05, 2016 revised manuscript accepted august 03, 2016 available online october 07, 2016 keywords: geodiversity index, geodiversity mapping, evaluation, gis, belgrade city area elements, such as anthropogenic soils, ditches, underground facilities, etc., as well as archaeological sites, collections of minerals and rocks, and stones used for the construction of buildings and monuments. according to gray (2004), geodiversity is particularly threatened by the development of urbanization that does not take into account the natural characteristics of the area. the largest threats are construction works which include the removal of surface layers and mixing them with construction material. the removal of surface soil disrupts the natural spatial forms and their characteristics, revealing barren bedrock. sediments, fossils and rocks may be lost; water quality is reduced. urbanization causes anthropogenization (even total destruction) of individual elements of geological diversity and at the same time it leads to the formation of new anthropogenic elements of space that can be numerous and occupy a larger area than the natural ones. for example, changes in soil usage lead to changes in soil quality (physical, biological and nutritional changes in value), the loss of organic matter and a general reduction of pedodiversity. anthropogenized soils disrupt the natural system through changes of erosion, biodiversity, pollution, and environmental sustainability (fanning & fanning, 1989). another great threat is the permanent covering of geodiversity elements with asphalt and concrete for construction purposes. apart from the protection of an object itself, the management needs to protect specific aspects, which are of geological interest. preserved geodiversity is a foundation of a healthy environment because it is a part of the natural mechanisms, representing the basis for a better quality of life. the evaluation of geodiversity, its spatial distribution and threats, to which it is exposed, contribute to the sustainable manag eo lo gi a c ro at ic a geologia croatica 69/3326 resources (natural and social) in a sustainable manner. one of the prerequisites of the appropriate planning and management is a scientifically based assessment of the value of geodiversity and its spatial distribution. the mapping of geodiversity ensures that the protective measures focus on the entire area and not just on the individual objects (pellitero et al., 2011). according to these authors, maps of geodiversity assessment would be used in spatial planning where the primary objective is the establishment of territorial zones, which should be managed based on their capacity. ruban (2010) considers that the descriptive version of geodiversity, which is often applied in assessing objects of geoheritage, is important for geoconservation, while for all levels of gement of georesources. this means finding a balance between the exploitation of these resources and their protection from overuse and improper use. it implies the development of plans and strategies to protect georesources from negative anthropogenic influences, while also making plans to protect the population and material goods from the negative effects and consequences of various geological and other natural geohazards (earthquakes, landslides, floods, weather, etc.). a richer geodiversity contri­ butes to more complex processes of cities development. if the geo diversity is in accordance with human needs, the development of the cities will be facilitated. to avoid conflicts, it is important to plan the development (spatial, economic, cultural...) and mana ge figure 1. (a) shaded hypsometric map (scilands, 2015) and the position of belgrade city area; (b) a satellite map of the studied area (google earth, 2009); (c) morphological and spatial (low land and hilly) map of the studied area (military geographical institute, 1989); (d) the administrative division of the territory of the city of belgrade. g eologia c roatica ilić et al.: application of the geodiversity index for the assessment of geodiversity in urban areas: an example of the belgrade city area, serbia 327 governance, a quantitative geodiversity assessment needs to be carried out. this paper presents one of the ways of quantifying the elements of geological diversity in an urban area, using the example of the belgrade city area. 2. study area belgrade, the capital of serbia, is located in southeast europe, on the balkan peninsula, at the confluence of the sava and the danube rivers (fig. 1a, b). it covers an area of 3227 km² of which almost 276.6 km² includes rivers and riparian land. according to the 2011 census (vukmirović, 2014), 1.639.121 inhabitants live in the territory of the city of belgrade, giving a population density of 508 inhabitants per km². belgrade accounts for over 3.6% of the territory of the republic of serbia, and is home to over 20% of the total serbian population. the territory is administratively divided into 17 municipalities (fig. 1d). from a geotectonic point of view, the belgrade city area includes the southern margin of the pannonian basin, northern parts of the vardar zone and the serbo-macedonian massif (maro vić et al., 2007). morphologically, two distinct units are clearly recognized: a) the southern part of the pannonian plain that represents vast plain and low land area located north of the sava and danube rivers, and b) a mountainous/hilly area (mts. šumadija, avala and kosmaj) located south of the sava and danube rivers (fig.1c). the primary morphological relief of the belgrade city area results from the tectonic movements that occurred during the palaeogene and early neogene. during the oligocenemiocene, a few horsts (mt. avala, mt. kosmaj) and a large-scale tectonic basin (pannonian basin) were created, as well as small tectonic depressions south of the pannonian basin (menković et al., 2013; marović et al., 2007). the turbulent tectonic activity was accompanied by volcanism, which lasted until the end of the miocene. volcanic landforms created during this period are not preserved in the territory of belgrade, instead igneous rocks from that period (mt. avala, mt. kosmaj) and pyroclastic material can be observed. the traces of the complex and turbulent geological history can be analyzed based on various indicators. the oldest known rocks in the territory of belgrade belong to the devonian-carboniferous age (dimitrijević et al., 1985a,b; filipović et al., 1980; pavlović et al., 1980; filipović et al., 1978; dimi­ trijević et al., 1975a,b). however, the geological structure of the hilly-mountainous area south of the sava and the danube rivers is much older and more complex than the structure of lowland terrain north of them. aquatic and terrestrial phases alternated several times, leaving behind the traces that, depending on the age and later geomorphological processes, are more or less preserved. the first determined marine phase began in the upper jurassic, about 150 million years ago and lasted throughout the cretaceous until about 65 million years ago (andjelković, 1989; dimitrijević et al., 1985a,b; filipović et al., 1980; pavlović et al., 1980; dimitrijević et al., 1975a,b). during that time, the wider territory of the present belgrade was completely covered by the tethys ocean. based on poor geological evidence, throughout the palaeogene, the belgrade area was not covered by the sea, due to erosion or masking by subsequent transgressions. at the beginning of the middle miocene, about 15 million years ago, the belgrade area was flooded by the central paratethys sea (rundić et al., 2013; rundić, 2010). this palaeogeographic regime lasted more than 3 million years and occasionally there were a few connections to the world ocean. however, at the middle/upper miocene boundary (ca.11.6 ma), due to tectonic uplift of the carpathian mountains, the aforementioned seaways were broken. thus, the isolated marine ecosystem, under the increasing influence and influx of freshwaters from the adjacent land, slowly turned into a large, long-lived lake – lake pannon (ter borgh et al., 2013; rundić et al., 2011). this was the largest aquatic system in central europe, characterized by an endemic fauna. during the upper miocene-pliocene, progradation processes and the considerable input of terrigenous materials led to successive infilling of this lake (radivojević et al., 2014). in place of the large lake, only smaller lakes and marshes remained. this area then finally dried out about 3.5 million years ago, when the continental phase started and which has continued to the present, (andjelković, 1989; dimitrijević et al., 1985a,b; filipović et al., 1980; pavlović et al., 1980; dimitrijević et al., 1975a,b). some authors consider that presently there are particular remnants of the marine-limnic morphology, although fluvial and hillslope relief dominates (men ković et al., 2013). the remaining ponds and lakes after the loss of the lake pannon became part of the danube river network. during the pleistocene ice ages, the present belgrade area was not glaciated, but the interchange of dry and wet periods affected the intensity of erosion. the most intense processes were fluvial, aeolian, hill-slope and karstic. during the quaternary, neotectonic activity took place influencing the intensity of particularly the fluvial and hill­slope erosional processes. unlike the sediments from older geological periods deposited in marine conditions, quaternary sediments (fluvial, lacustrine, aeolian, etc.) were deposited on land. the early and middle pleistocene is represented by river and lake gravels and sands with the presence of corbicula bivalve shells (rundić, 2010). loess formations, occurring in the form of loess plateaus (north of the sava and danube) and slope loess (south of the sava and danube) are characteristic of the upper pleistocene. loess sediments were formed throughout the pleistocene, in continental conditions, by sand and dust blown from the north over the existing geological units and landforms (rundić, 2010; antono­ vić et al., 1978). during the holocene, the youngest sediments of belgrade are being formed, represented by alluvial deposits of the sava and the danube rivers, soils, hillslope sediments, etc. in hydrogeological terms, the territory of belgrade is extremely com plex (vranješ, 2012; filipović, 2003, 2005; miloje­ vić et al., 1971, 1975) and is divided into ten zones with corresponding sub-zones (vranješ, 2012). in a pedogeographical sense, the territory of belgrade includes two regions. the first pedogeographical area, north of the sava and the danube, is the steppe and forest-steppe region of the pannonian plain. the second pedogeographical area extends south of the sava and the danube rivers. in the pannonian plain, the alluvial deposits on river terraces host fluvisols, gleysol, chernozems, and solonchaks (iuss working group wrb, 2006). there are also loess plateaus with chernozems and salt marshes soils. south of the sava and the danube, neogene sediments prevail. overlying the sediments, eutric cambiosols developed, which dominate in the sequence: regosol – leptosol (rendzinas) – eutric cambisol – luvisol while the heavy sediments predominately contain clays (vertisol). in the areas of significant soil erosion there are many colluvial soils, and on the lower river ter races there are fluvisols, fluvic cambiosols and gleysols. within belgrade specifically in the urban area, technosols are common, especially in the area north of the sava and the danube rivers, where intensive backfilling started after world war ii. novi beograd was built on this terrain, and the low­intensity fillg eo lo gi a c ro at ic a geologia croatica 69/3328 ing continues today during almost all construction and infrastructure works. soil fill is most often composed of a mixture of natural materials and construction waste. numerous occurrences of surface and groundwater that modify the relief of belgrade are significant for geodiversity. given that fluvial erosion has the greatest influence on the formation of relief in belgrade, it is important to preserve and maintain the drainage network and watercourses. the hydrographic network of belgrade consists of permanent and seasonal smaller river and stream flows that belong to the basins of the sava, the danube and the velika morava rivers. it is estimated that there are over 300 watercourses in the belgrade area (dedić & inđić, 1990). in addition to surface waters, the belgrade area is characterized by a variety of groundwaters that occur at different depths depending on the geological composition, relief, sources, feedsand anthropogenic influences. the most abundant are the hills south of the sava and danube where groundwater sources of different yield, chemical composition and temperature occur. there are also occurrences of mineral and thermal waters (filipović, 2003; filipović et al., 1978; komatina, 1976; milojević et al., 1975; milojević et al., 1971). geodiversity is greatly influenced by contemporary climatic conditions that affect the intensity and scale of erosion, but also those that prevailed in the geological past, especially during the quaternary. at the beginning of the quaternary (i.e. pleistocene) cooling and the beginning of the ice age occurred, during which climatic conditions drastically changed. pleistocene cooling on the territory of belgrade was reflected through the shift between colder and drier with warmer and wetter phases. during the cold phases, there were intensive aeolian processes, while the fluvial processes subsided due to smaller amounts of surface water. in the warmer phases, aeolian processes were weaker, while the fluvial and karstic ones were more intense. the blowing of loess sediments during the pleistocene was particularly intense in the pannonian basin and somewhat weaker in the peripheral parts. during the holocene, when it comes to warming and changes in climate conditions which existed in the pleistocene, the climate was not stable, but there were fluctuations and changes. today, belgrade has a moderate continental climate (popović, 1990). as a result of urbanization due to the construction of settlements with high, densely packed buildings, street paving and the use of large amounts of concrete, the emergence of new sources of heat, and reduced vegetation cover, there is now the „town climate“ (popović, 1990). 3. methodology for the evaluation of geological diversity in this work the equation for the geodiversity index (gd) evaluation (1), proposed by serrano & ruiz-flaño (2007) was used: gd = eg r / ln s (1) where gd – geodiversity index; eg – number of different abiotic elements in the spatial unit; r – coefficient of roughness of the spatial unit; s – surface of the spatial unit (m2); ln – natural logarithm. in references that dealt with the quantitative assessment of geodiversity (melelli, 2014; sil va et al., 2013, 2014; pellitero et al., 2011; hjort & louto, 2010; serrano et al., 2009; serrano & ruiz-flaño, 2007), the spatial units in respect of which the assessment of geodiversity elements was made, were different forms of landscape or geomorphological units, types of habitat or the pixels of different sizes (grid model). due to terrain complexity, the uneven distribution of abiotic elements and a strong process of urbanization, the gd in this paper were not done for natural units, but for the entire administrative territory of the city of belgrade. it was divided into pixels sized 200x200 m and 1000x1000 m. pixel sizes were determined based figure 2. map of relief roughness of belgrade city area. g eologia c roatica ilić et al.: application of the geodiversity index for the assessment of geodiversity in urban areas: an example of the belgrade city area, serbia 329 on the size of the territory and the scale of input data (hjort & louto, 2010; hengl, 2006). after the analysis and calculations for both networks, it was found that the network 1000x1000 m is more suitable for the mapping and assessment of geodiversity for the whole territory of the city. for data analysis and the clearer presentation of the obtained spatial results, a geographic information system (gis) was used. this involved creation of the geodatabase from which records provided the information necessary for the assessment of geodiversity and its spatial distribution. in this study, we used an entity model that assumes that the phenomena in the real world can be clearly identified in the form of their attributes and spatial position. the main sources of geographical data were geological, geomorphological, pedological and hydrological maps of the territory of belgrade (scale 1:50k, 1:100k and 1:300k), data from the available published literature and data collected in the field. for entering, editing, analysis and creation of vector spatial data gis software package geomedia professional 6.3 by the intergraph corporation was used. to process rasters, the software package idrisi andes ™ was used. in order to obtain the coefficient of relief roughness of the spatial unit, the calculation represented in ćalić et al. (2012a, 2012b) was used. the authors obtained the roughness coefficients for northern serbia using the geomorphometrical analysis in idrisi andes ™ software package. the input data for the digital terrain model were taken from the srtm database, with 90 m resolution (usgs, 2011). this resolution was subsequently resampled from 90 m to 200 m. the grid cells were grouped into 5x5 moving windows in order to obtain the average elevation within each window. each cell was first assigned a value representing its ele­ vation difference from the average elevation within a window. the standard deviation of all differences within a moving window was assigned to the central cell, and this standard deviation value was treated as a roughness coefficient of the central cell. in this way, the standard deviation (i.e. roughness coefficient) illustrates the cell’s relation to its immediate surroundings. for the purposes of the present study of geodiversity index, the 200x200 m resolution was resampled to 1000x1000 m resolution (fig. 2). due to the size of the territory and the scale of the input data, the assessment of geodiversity was made at the level of elements: geological (lithological-stratigraphic), geomorphological (morphogenetic), pedological (basic soil types) and hydrological (rivers, springs). the assessment did not include the level of regions (rifts, neotectonic depressions) and micro level (minerals, fossils). also, the assessment did not include petrographic elements that are used for the construction of buildings and monuments as well as geoarchaeological elements. 4. results and discussion from various input data for the purposes of calculating the number of different abiotic elements, new maps were formed: a simplified geological map (fig. 3), morphogenetic map (fig. 4), map of soil types (fig. 5) and map of rivers and springs (fig. 6). in creating the geological-stratigraphic map, the basic geological map of serbia 1:100000 – sheets beograd (dimitrijević et al., 1985a,b), pančevo (dimitrijević et al., 1975a,b), smede­ re vo (pavlović et al., 1980), obrenovac (filipović et al., 1980), gornji milanovac (filipović et al., 1978; vladimirci (filipović et al., 1967) and data from both the literature and from the field were used. the data were simplified and grouped in different stratigraphic units (fig. 3). the rocks that are particularly specific and that further affect the variety of geodiversity (phonolite and serpentinized peridotites) were placed in a separate category. to create a morphogenetic map (fig. 4), the data from the geomorphological map of serbia 1:300000 (menković et al., 2013) as well asfield observations were used. due to the map scale, individual terrain elements and features were not plotted. instead, areas with predominant morphological procesfigure 3. a simplified geological map of belgrade city area. g eo lo gi a c ro at ic a geologia croatica 69/3330 ses and typical landforms were shown. the basis for creating the map of soil types (fig. 5) was the analogous basic pedological map of serbia 1:50000sheets beograd 1,2,3,4; arandjelovac 1,2; obrenovac 2,4; zrenjanin 3,4; požarevac 3 (institute of soil research, 1963). data were digitized and types of soilare harmonized with the fao classification (iuss working group wrb, 2006). to calculate hydrographic elements, the map of rivers and springs was created (fig. 6). the sources were the analogue map of water objects 1:50000 – sheets beograd 1,2,3,4; kragujevac 1,2; lazarevac 1,2; smederevo 1,3,4 and zrenjanin 4 (federal secretariat for national defence & the federal committee for agriculture, 1988) and the analogue topographic map 1: 300000 – sheets beograd and kragujevac (military geographical institute, 1988). geological, geomorphological, pedological and hydrological elements of geodiversity were quantified (fig. 7) in order to obtain a gd value for each pixel (size 1000x1000 m). the final refigure 5. the map of soil types in the studied area. figure 4. the morphogenetic map of belgrade city area. g eologia c roatica ilić et al.: application of the geodiversity index for the assessment of geodiversity in urban areas: an example of the belgrade city area, serbia 331 sults were classified into five categories (<5 very low, 5­10 low, 10-20 medium, 20-30 high, >30 very high (fig. 8). the results showed that „greater rugosity implies greater geodiversity“ (pellitero et al., 2011; serrano & ruizflaño 2009), which in the case of belgrade means that the gd is low in the pannonian plain area (ćalić et al., 2012a, 2012b) and increases with the increase of roughness coefficient. the reason for the very low gd value in the pannonian plain is primarily low altitude but also the homogeneity of rocks and soil in which ag gradation is dominant fluvial process. thanks to the climatic cha racteristics in these areas, the gd value is slightly higher in places showing development of aeolian relief forms and areas of major watercourses. low gd is characteristic of areas where the coefficient of roughness (r) is between 10­20, forest soil and pseudo-gley dominate, and the rocks of different ages are present. the mean value of gd includes more than 1/4 of the studied area and it is represented in the territory where r is greater than 20, and geological and soil composition are more heterogeneous. increased relief roughness intensified geomorphological processes, which led to the creation of diverse landforms. high and very high gd covers 2.6% of the territory of belgrade, and is represented not only in the areas with the highest coefficient of terrain roughness (the mountains avala and kosmaj), but also in the areas where specific geological structure and intensive geomorphological processes (the valley of the topčider river, the valley of vrčin river) occur. very high gd is present in areas of serpentinized peridotites and the rocks of the upper jurassic and upper cretaceous and high gd is encountered in areas of rocks of different geological age (upper jurassic, badenian, sarmatian, pontian, pleistocene, and holocene). of the geomorphological processes present in the areas with the highest gd, the most intense are hillslope and marine-limnic, while fluvial, colluvial and karst are of lower intensity. soils with very high gd are the rendzina, acidic brown soil, chernozem, brown forest soil, while gd of the alluvial land is relatively small. from the geoconservation point of view, it is very important that high gd is found in the populated areas, which facilitates geoconservation activities. the great advantage is that a part of the areas where gd is very high or high is already protected by the state as the landscape of outstanding features (avala, kosmaj). in the valley of the vrčin river, and leštane where gd is very high as well as in other areas with high gd, geoconservation activities have not yet been undertaken (in the areas of the municipality of novi beograd, grocka, lazarevac, sopot, obrenovac, barajevo). the significant drawback is that the process of urbanization (the river is partly channeled and passes through the industrial zone) affects the valley of the topčiderska reka river. curiously, the areas with very high as well as areas with very low gd are less populated to uninhabited (fig. 9). population is the most intense in the areas with small and medium values of gd. varied geodiversity is good in the context of geoconservation, preventing degradation, biodiversity protection, etc. however, in a functional sense, low gd does not necessarily mean that these areas are „less important“. if we observe the example of belgrade, the best land for agricultural production is represented in the areas with very low gd. thus, calculated geodiversity is most useful in the context of protecting the diversity of natural values and the development of commercial sectors that rely on this diversity. however, for industries such as agriculture or construction the social and economic value of geological diversity must also be taken into consideration. geodiversity has different levels of importance and value de pending on whether it is represented in the town centre itself or in the wider environment, including the surrounding municipalities. in the very urban centre, its importance is related to the construction of buildings for housing and overhead and underground infrastructure facilities (water supply, rain and sewage systems, telecommunications and electrical installations, heating and gas pipelines, etc.), as well as for the disposal of municipal and industrial waste (nazzal et al., 2015, davidson et al., figure 6. the map of rivers and springs in the studied area. g eo lo gi a c ro at ic a geologia croatica 69/3332 figure 7. number of different abiotic elements (eg): a) soil b) deluvio-proluvial relief c) eluvial relief d) eolian relief e) fluvial relief f) fluvio-swamp relief g) colluvial relief h) karstic relief i) marine-lacustrine relief j) geology k) rivers l) springs. g eologia c roatica ilić et al.: application of the geodiversity index for the assessment of geodiversity in urban areas: an example of the belgrade city area, serbia 333 2006). in suburban areas, which are partly urbanized, its significance is in the use of minerals (stone, clay, gravel, sand and other non-metals) and energy resources (lignite), food production (land), water supply (groundwater sources, geothermal sources), etc. in urban areas, geomorphological objects are evaluated main ly based on the value they have for man. according to erhartič & zorn (2012) the relief forms become natural value only if they also contain a social component. relief forms, particularly in urban areas, are the source of ecosystem services (geosystem services) that are fundamental for an environmentally sustainable economy and social development, through supplying the population with economic, scientific, cultural or other goods (kiernan, 2013). however, although they have great significance for the development of cities, during construction each shape that deviates from a flat one is considered unfavourable and its modification is planned. jarman (1994) notes: „wherever the development starts there is a tendency to eliminate the characteristics of relief rather than incorporate it into local development plans“. also, in addition to destroying the existing relief, the evolution of new forms of anthropogenic (technogenic) relief is created. in spatial planning, the elements of the relief should be taken into account and the threats that can jeopardize its diversity and values must be reduced. gray (1997) notes that the intensity of factors that cause adverse effects depends on the ability of the landscape to absorb morphological changes. when belgrade was planned, little attention was paid to the relief, and most attention was paid to fit in and adapt the buildings to the kalemegdan ridge and few thoughts were given to the territorial expansion of the city. interestingly, the intense urbanization of belgrade demanded adjusting and modifying the properties of the relief because of its inadequacy for the construction of housing infrastructure. the permanent loss of geodiversity is particularly evident in the exploitation of mineral resources in the active quarries and open pit mines of the kolubara basin. lignite mining has led to the destruction of fertile lands in the alluvial plain of the kolubara river and its tributaries, and in their place barren soil of different materials has been piled up (cvetković et al., 2013; pruvot et al., 2006). in addition to the destruction of arable land, there was the destruction of the geological, geomorphological and hydrological elements of geodiversity as well figure 8. the geodiversity index map of the studied area. g eo lo gi a c ro at ic a geologia croatica 69/3334 as environmental changes and the disruption of the entire landscape. as a result of the plant’s operation, ash deposits were produced at the thermal power plant „nikola tesla“ a and b in obrenovac, which occupy an area of approximately 800 ha. they have negative effects on human health and degrade the overall geological diversity and the entire ecosystem of belgrade (gallagher et al., 2008; de kimpe & morel, 2000; ivanović et al., 1997). in belgrade, there are no raw metal mines and the older mines in the avala and kosmaj mountains are no longer active. the number of excavations of non-metallic materials, and to a lesser extent, excavations of sand and gravel in the alluvial plains of major rivers, quarries, excavation of clay have been reduced. other threats to the geodiversity of belgrade are: torrential flows, flooding the bottom of the riverbed, water erosion, landslides, river channeling, traffic which causes pollution of the air, water and land, construction of buildings and infrastructure systems, industry, changing land use, formation of ash deposits from thermal power plants, ore exploitation, quarries, gravel, compaction, acidification and salinization of soil, reduction of organic matter, climate change and loss of organic matter in soils, disposal of communal and industrial waste. the vulnerability is increased as elements are older or if they are built in softer rocks, or if they are vulnerable to natural and anthropogenic processes. 5. conclusion it is not possible to provide most of the data and information on geodiversity using only the basic geological, geomorphological, hydrological and soil maps. it is necessary to make a geodiversity map, which would serve as a basis for creating strategies for planning and management. the results showed that the quantitative evaluation of geodiversity provides essential data relating to the natural values of an area. choosing an aspect in which the work assessment and detail of spatial information depends on the size of the territory and purposes. the paper applied the grid-based system (pixel size is 1000x1000 m) using a data scale of 1:50.000 to 1:300.000. making assessments at this scale allowed illustration of the areas of the richest geodiversity. it also serves as a guide line for the direction of the future spatial development of the city, primarily in order to protect the natural values of the city of belgrade. the highest index values of geodiversity can be an indicator of which areas should be protected (i.e. the valley of the topčider river and the valley of vrčin river). assessment at this scale is not suitable for the protection of individual phenomena. it can be an indicator of where the significant objects of geoheritage are, but to study individual geosites it is necessary to conduct an analysis of large­scale data with a sufficient degree of detail. the assessment of geodiversity is essential in geoconservation activities. also, the results showed that the areas with the highest values of gd have the potential for geoconservation, but that these are not the areas that are densely populated (i.e. the mountains of avala and kosmaj). the highest population density is in the areas where the values of gd are medium and low. it is interesting that the areas with small gd have great significance for the development of the city (i.e. the pannonian basin domain). although these areas are less populated and with less variety of geodiversity, they are the most important agricultural areas. there fore, the sustainable use of geodiversity should be approached from the aspect of importance for the development of the city in both economic and social terms. acknowledgement some parts of this study are supported by the ministry of education, science and technological development of the republic of serbia (projects no. 176008, 47007 and 176015). figure 9. two of the largest protected areas (avala and kosmaj mts.) with a high gd index. on the map smaller protected areas as well as protected sites are not displayed. g eologia c roatica ilić et al.: application of the geodiversity index for the assessment of geodiversity in urban areas: an example of the belgrade city area, serbia 335 references alexandrowicz, z. & kozlowski, k. (1999): from selected geosites to geodiversity conservation: polish example of modern framework.– in: barettino, d., vallejo, m. & gallego, e. (eds): towards the balanced management and conservation of the geological heritage in the new milenium, sociedad geológica de españa, madrid 52–54. andjelković, m. (1989): geologija šire okoline beograda 4–paleogeografija [geo­ logy ofwider belgrade area 4 – paleogeography – in serbian)].– zavod za re gionalnu geologiju i paleontologiju, beograd. antonović, t., bogdanović, m., živković, ž., ćorović, r. & trifuno­ & trifunović, m. (1978). zemljište područja beograda južno od save i dunava [the soil of the belgrade territory, south of the sava and danube – in serbian].– gradski geodetski zavod, beograd. benito-calvo, a., pérez-gonzález, a., magri, o. & meza, p (2009): assessing regional geodiversity: the iberian peninsula.– eart surf process landf, 34/10, 1433–1445. cvetković, ž., logar, m. & rosić, a. (2013): mineralogy and characterization of sedimentary particles of the aero sediments collected in the vicinity of power plants and the open pit of coal mine: kolubara (serbia).– environmental science and pollution research, 20/5, 3034–3049. ćalić, j., gaudenyi, t., milošević, m.v., štrbac, d. & milivojević, m. (2012a): geomorphometrical method for delineation of plains – case study of the south-eastern (serbian) segment of the pannonian plain.– carpathian journal of earth and environmental sciences, 7/2, 239–248. ćalić, j., milošević, m.v., gaudenyi, t., štrbac, d. & milivojević, m. (2012b): panonska nizija kao morfostrukturna jedinica srbije [the pannonian plain as morphostructural unit of serbia– in serbian].– glasnik srpskog geografskog društva, sveska xcii/1, 47–62. davidson, c.m., urquhart, g.j., biasioli, m., duarte, a.d., diaz-barrientos, e., grcman, h., hossack, l., hursthouse, a.s., madrid, l.s. rodrigues, s. & zupan, m. (2006): fractionation of potentially toxic elements in urban soils from five european cities by means of a harmonised sequential extraction procedure.– analytica chimica acta, 565, 63–72. de kimpe, c.r. & morel, j.l. (2000): urban soil management, a growing concern.– soil science, 165, 31–40. dedić, m. & inđić, d. (1990): akumulacije u službi rešavanja ekoloških problema područja beograda [accumulation in the service of solving the environmental prob­ lems of the belgrade – in serbian].– in: ekološki problemi beograda, savez društva inžinjera i tehničara beograda, beograd, 2, 227–239. dimitrijević, m., karamata, s., sikošek, b. & veselinović, d. (1975a): osnovna geološka karta sfrj 1:100000, list pančevo l 34­114 [basic geological map of sfry 1:100000, pančevo sheet – in serbian].– savezni geološki zavod, beograd. dimitrijević, m., karamata, s., sikošek, b. & veselinović, d. (1975b): osnovna geološka karta sfrj 1:100000. tumač za list pančevo l 34­114 [basic geological map of sfry 1:100000, geology of the pančevo sheet – in serbian].– savezni geološki zavod, beograd. dimitrijević, m., dragić, d., karamata, s., petrović, b., sikošek, b., šuvački, v. & veselinović, d. (1985a):osnovna geološka karta 1:100000, list beograd l 34­113 [basic geological map of sfry 1:100000, geology of the beograd sheet – in serbian].– savezni geološki zavod, beograd. dimitrijević, m., dragić, d., karamata, s., petrović, b., sikošek, b., šuvački, v. & veselinović, d. (1985b): osnovna geološka karta 1:100 000. tumač za list beograd l 34­113 [basic geological map of sfry 1:100000, geo­ logy of the beograd sheet – in serbian].– savezni geološki zavod, beograd. erhartič, b. & zorn, m. (2012): geodiversity and geomorphosite research in slo­ venia. – geografski vestnik, 84/1, 51–63. fanning d, s. & fanning, m.c.b. (1989): soil morphology, genesis and clas sifi cation.– wiley, new york, 395 p. federal secretariat for national defence & the federal committee for agriculture (1988): karta vodnih objekata 1:50000 listovi beo grad 1,2,3,4; kragujevac 1,2; lazarevac 1,2; smederevo 1,3,4; zrenjanin 4 [map of water objects 1:50000 – sheets beograd 1,2,3,4; kragujevac 1,2; laza­ revac 1,2; smederevo 1,3,4 and zrenjanin 4 – in serbian].– savezni sekretarijat za narodnu odbranu & federalni komitet za poljopriverdu, beograd. filipović, i., veselinović, m., rajčević, d., bodić, d., petronijević, s., rakić, m., gagić, n. & milićević, m. (1967): osnovna geološka karta 1:100000 vladimirci l 34–124 [basic geological map of sfry 1:100000, geo­ logy of the vladimircisheet – in serbian].– zavod za geološka i geofizička istra ži­ vanja, beograd. filipović, i., marković, b., pavlović, z., rodin, v. & marković, o. (1978): osnovna geološka karta 1:100000. tumačza list gornji milanovac l34­137 [basic geological map of sfry 1:100000, geology of the gornji milanovac sheet – in serbian].– zavod za geološka i geofizička istraživanja, beograd. filipović, i., rodin, v., pavlović, z., marković, b., milićević, m. & atin, b. (1980): osnovna geološka karta 1:100000, list obrenovac l 34­125 [ba­ sic geological map of sfry 1:100000, geology of the obrenovac sheet – in serbian].– zavod za geološka, hidrogeološka, geofizička i geotehnička istraživanja „geozavod“, beograd. filipović, b. (2003): mineralne, termalne i termomineralne vode srbije [mineral, thermal and thermo­mineral waters of serbia – in serbian].– institut za hidrogeologiju rudarsko­geološkog fakulteta, beograd. filipović, b., krunić, o. & lazić, m. (2005):regionalna hidrogeologija [regio­ nal hydrogeology – in serbian].– univerzitet u beogradu, rudarsko­geološki fa­ kultet, beograd. gallagher, f.j., pechmann, i., bogden, j.d., grabosky, j. & weis, p. (2008): soil metal concentration and vegetative assemblage structure in an urban brownfield.– environmental pollution, 153, 351–361. google earth 5.0. (2009): belgrade, serbia. 34t 465986.61me, 4942464.02mn, eye alt 145.98km. landsat 2013. http://www.google.com/earth/index.html gray, m. (1997): planning and landform: geomorphological authenticity or incongruity in the countryside?– area, 29/4, 312–324. gray, j.m.(2004): geodiversity. valuing and conserving abiotic nature.– john wiley & sons ltd, chichester. hengl, t. (2006): finding the right pixel size.– computers and geosciences, 32, 1283–1298. hjort, j. & louto, m. (2010): geodiversity of high latitude landscapes in northern finland.– geomorphol, 115, 109–116. institute of soil research (1963): osnovna pedološka karta srbije listovi beograd 1,2,3,4; arandjelovac 1,2; obrenovac 2,4; zrenjanin 3,4; požarevac 3 [basic pedological map of serbia 1:50000 – sheets beograd 1,2,3,4; arandjelovac 1,2; obrenovac 2,4; zrenjanin 3,4; požarevac 3 – in serbian].– institut za proučavanje zemljišta, beograd. iuss working group wrb (2006): world reference base for soil resources 2006.– world soil resources reports, 103, fao, rome. ivanović, m., ivanović, v. & stajević, d. (1997): aerozagađenje prašinom u naseljima ugljenih rudarskih basena [air pollution by dust in coal mining basein settlements – in serbian].– xxv savetovanje sa međunarodnim učešćem ˝zaštita vazduha 97˝, 249–255. jarman, d. (1994): geomorphological authenticity: the planning contribution.– in stevens, c., gordon, j.e., green, c.p. & macklin, m.g. (eds): conservingour landscape.– english nature, peterborough, 41–45. kiernan, k. (2013): nature, severity and persistence of geomorphological damage caused by armed conflict.– land degradation & development. doi: 10.1002/ldr.2216 kozlowski, s. (2004): geodiversity: the concept and scope of geodiversity.– przeglad geologiczny, 52, 8/2, 833–837. manosso, f.c. & nóbrega, m.t. (2015): calculation of geodiversity from landscape units of the cadeado range region in paraná, brazil.– geoheritage. doi: 10.1007/s12371-015-0152-1 marović, m., toljić, m., rundić, lj. & milivojević, j. (2007): neoalpine tectonics of serbia.− serbian geological society, belgrade. melelli, l. (2014): geodiversity: a new quantitative index for natural protected areas enhancement.– geojournal of tourism and geosites, vii, 1, 13, 13103-142, 27–37. menković, lj., košćal, m., mijatović, m. &, živković, m. (2013): geo­ morfološka karta srbije 1:300000 s tumačem [geomorphological map of serbia 1: 300000 with an interpreter – in serbian].– ministarstvo rudarstva, prirodnih resursa i prostornog planiranja, beograd. military geographical institute (1988): topografska karta 1: 300000 listovi beograd, kragujevac [topographic map 1: 300000 – sheets beograd and kragujevac – in serbian].– vojnogeografski institut, beograd. military geographical institute (1989): topografska karta 1:1000000 [to­ po graphic map 1:1000000 – in serbian].– vojnogeograsfki institut, beograd. milojević, n., filipović, b. & dimitrijević, n. (1971). hidrogeološka rejo ni­ zacija teritorije beograda [hydrogeological zoning of territory of belgrade – in serbian].– zbornik radova rudarsko­geološkog fakulteta, 13, beograd. milojević, n., filipović, b. & dimitrijević, n. (1975): hidrogeologija teritorije grada beograda sa hidrogeološkom kartom razmere 1:100000 [hydrogeol­ ogy of the belgrade city area with hydrogeological map 1:100000 – in serbian].– belgrade. nazzal, y.h., al-arifi, n.s.n., jafri, m.k., kishawy, h.a., ghrefat, h., el-waheidi, m.m., batayneh, a. & zumlot, t. (2015): multivariate statistical analysis of urban soil contamination by heavy metals at selected industrial locations in the greater toronto area, canada.– geologia croatica, 68/2, 147–159. pavlović, z., marković, b., atin, b., dolić, d., gagić, n., marković, o., dimitrijević, m. &, vuković, m. (1980): osnovna geološka karta 1:100000, list smederevo l 34­126 [basic geological map of sfry 1:100000, geology of the smederevo sheet – in serbian].– zavod za geološka, hidrogeološka, geofizička i geotehnička istraživanja „geozavod“, beograd. pellitero, r., gonzález-amuchastegui, m.j., ruiz-flaño,p. & serrano, e. (2011): geodiversity and geomorphosite assessment applied to a natural protected area: the ebro and rudron gorges natural park (spain).– geoheritage, 3, 163–174. g eo lo gi a c ro at ic a geologia croatica 69/3336 pereira, d.i., pereira, p., brilha, j. & santos, l. (2013): geodiversity assessment of parana state (brazil): an innovative approach.– environmental management, 52, 541–552. pruvot, c., douay, f., herve, f. & waterlot, c. (2006): heavy metals in soil, crops and grass as a source of human exposure in the former mining areas.– journal of soils and sediments, 6, 215–220. popović, z. (1990): odlike gradske klime beograda [characteristics of urban climate in belgarde.– in serbian].– in: ekološki problemi beograda, savez društva in ži­ njera i tehničara beograda, beograd, 2, 307–317. radivojević, d., magyar, i., ter borgh, m. & rundić, lj. (2014): lake pannon – serbian side of the story.– proceed. of the xvi serbian geological congress, 54–60, donji milanovac, serbia. ruban, d.(2010): quantification of geodiversity and its loss.– proc. geol. assoc., 121, 326–333. rundić, lj. (2010): geološki objekti i prirodni fenomeni kao integralni elementi geodiverziteta grada beograda [the geological structures and natural phenomena as integral elements of geodiversity of the city of belgrade – in serbian].–rudarskogeološki fakultet univerziteta u beogradu, beograd. rundić, lj., ganić, m., knežević, s. & soliman, a. (2011): upper miocene pannonian sediments from belgrade (serbia): new evidence and paleoenvironmental considerations.– geologica carpathica, 62/3, 267–278. rundić, lj., knežević, s. & rakijaš, m. (2013): badenian marine transgression: new evidence from the vrdnik coal basin (northern serbia).– ann. geol. pennins. balk, pol. 74, 9–23. scilands (2015): the shaded hypsometric maps of hungary, slovakia, slovenia, croa tia, serbia, bosnia-herzegovina, montenegro.– available online at: http:// www.scilands.de/ serrano, e. & ruiz-flano, p. (2007):geodiversity: concept, assessment and territorial aplication. the case of tiermes-caracena (soria).– boletín de la a.g.e. n.º 45–2007, 389–393. serrano, e. & ruiz-flaño, p. (2007): geodiversity. a theoretical and applied concept.– geogr. helv., 62, 3, 140–147. serrano, e. & ruiz-flaño, p. (2009): geomorphosites and geodiversity.– in: rey nard, e., coratza, p. & regolini-bissig, g. (eds.): geomorphosites, 49–61. serrano, e., ruiz-flaño, p. & arroyo, p. (2009): geodiversity assessment in a rural landscape: tiermes-caracena area (soria, spain).– mem. descr.carta. geol. ital., 86, 171–178. silva, j.p., pereira, d.i., aguiar, a.m. & rodrigues, c. (2013): geodiversity assessment of the xingu drainage basin.– journal of maps. doi: 10.1080/ 17445647.2013.775085 silva, j.p., rodrigues, c. & pereira, d.i. (2014): mapping and analysis of geodiversity indices in the xingu river basin, amazonia, brazil.– geoheritage. doi: 10.1007/s12371-014-0134-8 stepišnik, u. & repe, b. (2015). identifikacija vročih točk geodiverzitete na primeru krajinskega parka rakov škocjan.– dela, 44, 45–62. retrieved from http://revije. ff.uni-lj.si/dela/article/view/dela.44.1.45-62/5460 ter borgh, m., vasiliev, i., stoica, m., knežević, s., matenco, l., krijgsman, w., rundić, lj. & cloething, s. (2013): the isolation of the pannonian basin (central paratethys): new constraints from magnetoand biostratigraphy.– global and planetary change, 103, 99–118. usgs (2011): shuttle radar topography mission (srtm) 90m digital elevation data, available online at: http://srtm.csi.cgiar.org/ vranješ, a. (2012): hidrogeotermalni resursi teritorije grada beograda [geothermal resources of the city of belgrade – in serbian with an english abstract].– phd thesis (in serbian), faculty of mining and geology, university of belgrade. vukmirović, d. (2014): 2011 census of population, households and dwellings in the republic of serbia – population.– statistical office of the republic of serbia, belgrade. 2016 | 69/3 | 317–324 | 6 figs. | 4 tabs. | www.geologia-croatica journal of the croatian geological survey and the croatian geological society 1. introduction fly ash is the product of burning coal and arises from inorganic substances melting in the thermal power plants. the fly ash particles have a spherical shape, dimensions of 0.074-0.005mm, are of low density, very mobile and can cause a number of problems in the environment. slag is a mineral mixture that consists of material melted in the combustion process and other parts of noncombustible material. it falls through the latticed stokehole and is rapidly cooled and extinguished in water. the fly ash and slag landfills in serbia occupy an area of 1639 ha and if they are under constant control and monitoring, significantly influence the disruption of the environment, which is reflected in the pollution of: air, soil, surface water and groundwater, vegetation cover, as well as in the steady ecosystems disruption that affects human health (miletić & ilić, 2007). all the negative environmental indicators caused by fly ash and slag can be eliminated or reduced if they are used as building material for road construction and other trafficked areas. the using of fly ash and slag as secondary materials for road constructions, saves huge amounts of standard building materials (stone, gravel, sand), which are non-renewable. most of the research is based on an examination of the chemical composition of the ash (thomas, 2007; kim et al., 2005), the mineral ash composition (životić et al., 2015), the mineral ash and coal composition (ward & french, 2005) and chemical-mineral ash composition (vassilev et al., 2013; vassilev et al., 2014; vassilev et al., 2003; vassilev et al., 2004a; vassilev et al., 2004b; vassilev & menendez, 2005). there are many papers of narrower scope that establish correlations between the chemical, mineral and physical properties of fly ash (vassilev & vassileva, 2007). based on the most common characteristics (chemical and mineral composition) of ash and slag from the kolubara and kostolac coal basins, the research objectives presented in this paper are the laboratory testing and research of the physi properties of fly ash and slag from the power plants miloš šešlija1, aleksandra rosić2, nebojša radović1, milinko vasić1, mitar đogo1 and milovan jotić3 1 university of novi sad, faculty of technical sciences, department of civil engineering and geodesy, trg dositeja obradovića 6, 21000 novi sad, republic of serbia; (slavijasrb@gmail.com) 2 university of belgrade, faculty of mining and geology, đušina 7, 11000 belgrade, republic of serbia 3 highway institute a.d., kumodraška 257, 11000 belgrade, republic of serbia doi: 10.4154/gc.2016.26 abstract this paper describes the physical, chemical and mineral properties of ash and slag, which were taken from thermal power plants nikola tesla a, nikola tesla b, kostolac a and kostolac b. the knowledge of the mineralogical material composition is important because the type of minerals directly determines the properties of the fly ash and slag and their possible application. laboratory tests showed that ash and slag samples consist of the following minerals: amorphous materials, quartz, feldspar, mullite, melilite, cristobalite, haematite and calcite. the fly ash and slag chemical properties are the most important indicators in the evaluation of their suitability as a building material. the ash and slag chemical composition is composed of the following chemical components: sio2, al2o3, fe2o3, cao, mgo, so3, s, na2o and k2o. results of laboratory tests show that fly ash and slag have variable chemical, mineralogical and physical properties that are dependent on the natural composition, quality of coal from basin, the manner of combustion and place of ash deposition. article history: manuscript received march 24, 2016 revised manuscript accepted july 19, 2016 available online october 20, 2016 keywords: fly ash, slag, physical composition, chemical composition, mineral composition, x-ray diffraction method cal properties, chemical and mineral compositions of the fly ash from thermal power plants (pp) „nikola tesla a” (nt a), „nikola tesla b” (nt b), „kostolac „a” (ko a) and „kostolac b” (ko b). the physical properties of the ash and slag facilitate their use as building materials for transport infrastructure, reducing the use of natural resources inroad building projects. the chemical properties of fly ash and slag are the most important indicator in the evaluation of their suitability as a building material. knowledge of the material mineralogical composition is significant because the type of minerals directly determines the properties of fly ash and slag and their applications. the aim of this paper is based on establishing a correlation between the physical properties, chemical and mineral composition of the ash and slag. established correlations are indicators for defining the origin, properties, as well as the possibility of fly ash and slag application as a construction substitute thus preservinglimited reserves of natural building materials. 2. study area ppnt a is the most important producer of electricity in serbia and is built on the bank of the river sava. ppnt a is 4 km from obrenovac, ppnt b is located 16 km upstream from ppnt a (fig. 1). both ppnt use coal from the kolubara basin. the kolubara lignite basin is economically one of the most important coal basins in serbia. it is located about 60km ssw of belgrade, and covers an area of almost 600km2, extending in an e-w direction for up to 55km, and in the n-s direction up to 15km. this basin is divided into several fields („a”, „b”, „c”, „d”, „e”, „f”, „g”, „veliki crljeni”, „šopić-lazarevac”, „tamnava istok”, „tamnava zapad”, „radljevo”, „zvizdar” and „ruklade”; fig. 2). lignite is exploited in fields „c”, „d” and „tamnava zapad”. the d field which is the focus of this study is situated in the eastern part of the kolubara basin. when exploitation began it extended over an area of almost 20km2, now the g eo lo gi a c ro at ic a geologia croatica 69/3318 remaining surface with mineable coal seams is about 6km2. the northern border is represented by outcropping and erosion of the main coal seam. the western border of the deposit is a natural extension to the g field and the southern boundary to the e field. the eastern border is also marked by outcropping of the main coal seam (životić et al., 2013). since 1896, about 883.2mt of lignite in total, has been produced from the kolubara basin, of which 866.8mt was form open pit mines and 16.3mt from underground mines (active until 1974). annually, the kolubara basin produces about 30mt lignite, which amounts to 70% of the total coal production in serbia. according to the geological survey of the kolubara basin, the lignite resources and reserves are currently estimated at 2811mt. most of the lignite produced (90%) is used for electricity generation in thermal power plants „nikola tesla a” (nt a) and „nikola tesla b” (nt b). about 17 billion kwh is produced annually from kolubara coal, which represents 52% of serbia’s total electricity generation (životić et al., 2013). in the kostolac coal basin two thermal power plants were built. ppko a is located on the right bank of the river danube, figure 2. geological map of the kolubara basin (from životić et al., 2013). figure 1. map of the study area (www.maps.google.com). g eologia c roatica šešlija et al.: properties of fly ash and slag from the power plants 319 on the edge of place kostolac, while ppko b is located on the northeastern part of the kostolac coal basin near the village of drmno (fig. 1). the kostolac coal basin, covering an area of 145km2, is located about 90km east of belgrade. it is divided into three coal fields: the drmno field in the eastern, the ćirikovac field in the central and the smederevsko podunavlje field in the western parts of the basin (fig. 3). the drmno and ćirikovac fields are exploited, while the smederevsko podunavlje field is still under preliminary exploration (stojanović et al., 2012). 3. geology the area of the kolubara basin consists of palaeozoic, mesozoic, tertiary and quaternary rocks (fig. 4) (životić et al., 2015). the basement of this basin consists of devonian and carboniferous schists, gneisses, slates and sandstones, mesozoic mica-rich sandstones, shales, dolomitic limestones, limestones and flysch (alternation of limestones, marlstones, sandstones and siltstones), and tertiary phenoandesites, phenodacites, quartz-latite, ignimbrites and quartz-latite tuffs. the pontian (upper miocene) fresh water clastic sediments host three coal seams (kezović, 2011): seam iii or lower coal seam, seam ii or main coal seam and seam i or upper coal seam, having average thicknesses of 7m, 25m and 11m, respectively. the total thickness of the pontian series is between 250 and 320m. the basement of the kostolac basin consists of devonian crystalline rocks overlain by neogene sediments (stojanović et al., 2012) (fig. 3). the fresh water clastic coal-bearing series of the kostolac basin is also of upper miocene (pontian) age and hosts five coal seams, namely seam iii (the oldest and deepest) and seams ii-a, ii, i-a and i. only coal seams iii, ii and i are (or have been) explored in the drmno, ćirikovac and klenovnik open pits. the average thickness of coal seam iii throughout the whole basin is 19.38m, while it is 1.43m for iia, 4.14m for ii, 1.53m for ia and 13.90m for i coal seam (životić et al., 2015). 4. materials and methods the ash sampling was carried out nearthe electric filter in the cooling phase, before it came into contact with water. for technological reasons, the slag was sampled in the wet state. the necessary quantity of samples for the ash laboratory tests were provided on two occasions, in may and june, and the slag laboratory tests were conducted in may. after the sample collection, the required amounts of material were separated for the following tests: • physical examination of the ash and slag; • chemical analyzes of the ash and slag; • mineralogical tests of the ash and slag. the humidity samples, density of solid particles, grain size composition and ph value tests were done to determine the phy sifigure 3. location and coal fields of the kostolac basin (stojanović et al., 2012). g eo lo gi a c ro at ic a geologia croatica 69/3320 cal properties of the ash and slag. sample humidity was examined according to the standard en 1328-1, the solid particles volume weight test followed the standard en 1097-7, grain size composition was tested according to en 933-1, en 451-2 and srps u. b1.018., and the ph value test was done according to srps h. c8.209. all the chemical tests on the fly ash and slag were done according to standards srps b.h8.359-369 and srps b.h8.327. mineralogical sample properties of the fly ash and slag from ppnt a, ppnt b, ppko a and ppko b were determined by x-ray examinations. x-ray diffraction is a non-destructive experimental method based on the diffraction of x-rays withcrystal lattice sized wavelengths. this method is primarily used for quality analysis, due to the fact that it enables the crystal components to be identified, the type of crystal lattice to be determined, as well as the presence of certain phases in the system, the deformation of the crystal lattice, and the size of crystals. it can also be used for quantity analysis, or more precisely, for an estimation of the proportions of the different components in the sample (đorđe vić, 2012). all samples were tested using the powder diffractometer philips pw 1710. the diffraction patterns (diagrams) were obtained with cukα radiation (λ=1.54178x10–10 m), created in the x-ray tube at 30ma and a voltage of 40kv. sample recording was performed in the range of 2θ from 5 to 50° with a step of 0.02° and a retention time of 0.5s at each step. the data position of the diffraction peaks 2θ (°), the value of the flange distance d (m), and the corresponding intensities (i) use impulse unite (imp). 5. results and discussion the test results of the physical properties are shown in table 1. the mean values, as well as the minimum and maximum values of ash and slag samples, are shown. for each power plant, six samples of fly ash in may were selected and one sample of slag. in june, three samples of fly ash were selected, with a total of 36 samples of fly ash and four slag samples (table 1). the chemcial composition results of the fly ash and slag from the thermal power plant (pp) samples tested are shown in table 2. based on the analysis, the fly ash and slag from all four power plants have variable chemical composition. the chemical composition of samples consist mostly of silica (sio2), then alumina (al2o3), iron trioxide (fe2o3), calcium oxide (cao) and magnesium oxide (mgo), while the chemical elements of sulfur trioxide (so3), sulfur (s), sodium oxide (na2o) and calfigure 4. lithostratigraphic cross section column of the neogene from the kolubara and kostolac (životić et al., 2015). g eologia c roatica šešlija et al.: properties of fly ash and slag from the power plants 321 cium oxide (cao) are only present in very small quantities. the main reason for the variability of the chemical composition is the waste-rock presence of inorganic composition. based on the chemical composition the module r is determined, and is shown in fig. 5. the r module is used for determination of ash and slag classification according to the chemical composition. the formula for determining the r module is: 2 3 2 3 ( ) ( ) sio alor cao mgo fe o += + + (1) according to the size of the module r, the fly ash can be classified as silica-calcium (r<2), silicate (r = 2–6) or aluminumsilicate (r>6). table 1. physical properties of fly ash and slag. no. humidity of the sample (w) [%] fraction <63µm (<63 µm) [%] density <2.9 (<2.9) [g/cm3] ph values mena range mena range mena range nt a – m 0.43 0.30-0.57 40.67 16.0-68.0 2.11 2.05-2.15 11.88 nt a – j 0.29 0.22-0.38 22.67 16.0-30.0 2.09 2.08-2.10 12.76 nt b – m 0.26 0.08-0.71 44.67 35.0-51.0 2.13 2.08-2.20 11.53 nt b – j 0.20 0.15-0.28 51.33 46.0-57.0 2.10 2.05-2.16 13.15 ko a – m 0.17 0.10-0.23 17.33 15.0-19.0 2.08 2.04-2.11 11.02 ko a – j 0.41 0.37-0.47 65.00 48.0-81.0 2.13 2.02-2.33 12.79 ko b – m 0.31 0.13-0.49 18.00 10.0-25.0 2.11 2.08-2.15 11.30 ko b – j 0.27 0.23-0.30 65.33 61.0-69.0 2.32 2.30-2.34 12.00 nt a (s) 51.21 – 1.00 – 2.15 – 10.04 nt b (s) 19.31 – 1.00 – 2.17 – 9.36 ko a (s) 28.56 – 2.00 – 2.04 – 7.77 ko b (s) 42.55 – 1.00 – 2.16 – 8.57 m – fly ash for month may; j – fly ash for month june; (s) – slag; w – humidity of the sample; <63μm – fraction of less than 63μm; <2.9 – density of less than 2.9g/cm3; ph – ph values; nt – nikola tesla; ko – kostolac table 2. results of chemical analyses of fly and slag taken from the power plants. no. loi 1000 sio2 al2o3 fe2o3 cao mgo so3 s na2o k2o mass (%) nt a – m 6.43 51.64 21.87 5.54 1.05 3.01 0.85 0.33 0.57 1.05 nt a – j 7.2 51.43 22.01 6.03 1.16 2.83 0.54 0.21 0.43 1.16 nt b – m 2.58 55.38 22.57 5.46 8.30 2.87 0.45 0.18 0.45 1.12 nt b – j 2.11 51.88 22.49 6.61 10.44 3.28 0.66 0.26 0.58 1.23 ko a – m 2.21 51.96 23.22 9.82 7.80 2.62 0.33 0.13 0.44 0.77 ko a – j 4.18 44.55 20.80 11.23 11.71 2.73 2.45 0.98 0.50 0.69 ko b – m 3.37 51.41 22.13 9.98 8.05 2.50 0.53 0.21 0.48 0.76 ko b – j 1.98 46.04 21.67 11.44 11.10 2.64 2.27 0.88 0.51 0.67 nt a (s) 9.88 51.06 20.50 6.14 7.27 2.70 0.12 0.05 0.53 1.23 nt b (s) 10.5 52.12 20.97 6.30 5.51 2.30 0.16 0.06 0.51 1.02 ko a (s) 36.02 32.98 12.24 7.56 5.53 1.83 1.96 0.78 0.48 0.69 ko b (s) 4.47 48.91 21.54 11.32 8.87 2.43 0.23 0.40 0.49 0.74 loi 1000 – loss on ignition 1000°c; m – fly ash for month may; j – fly ash for month june; (s) – slag; nt – nikola tesla; ko – kostolac figure 5. the r module according to pp (m – fly ash for month may; j – fly ash for month june; (s) – slag; nt – nikola tesla; ko – kostolac). g eo lo gi a c ro at ic a geologia croatica 69/3322 according to this classification, fly ash from ppnt a for may and june belongs to the aluminum-silicate group, and slag belongs to a silicate group, because the module is in the range of 2 to 6. fly ash from ppnt b, ppko a and ppko b belongs to a silicate group, and slag from all three of these power plants also belongs to a silicate group. percentage compositionof minerals in the samples of the fly ash and slag are shown in table 3. comparing the results of test samples (table 3) by the x-ray diffraction method it can be observed that: • all samples of ash contain a significant amount of amorphous material (am); • samples of ash from obrenovac include quartz (q) and feldspar (f) as the most common minerals, while the other identified minerals are represented in subordinate amounts. samples of ash from kostolac contain significantly higher amounts of haematite (he) and anhydrite (an); • samples of slag from obrenovac are similar to each other compared to the samples of slag from kostolac which show a greater difference with each other. 5.1. relationships between physical, chemical and mineral composition the reserach studied the dependence between the physical, chemical and mineral compositionafter which certain correlation coefficients were determined and compared between the ash and slag. dependence for all the samples was done using polynomial functions, because only this function gave the best correlation results. results of the correlation coefficient, as a relationship and a correlation sign, are shown in table 4. based on analysis of the table 3. the percentage composition by mass of minerals in the samples of the fly ash and slag. no. the amorphous material q f m ml an cr he cao total mass (%) nt a – m 58 16 10 5 5 3 3 – – 100 nt a – j 66 17 9 3 2 2 – – – 99 nt b – m 50 17 12 6 4 7 4 – – 100 nt b – j 50 10 14 8 6 7 3 – 2 100 ko a – m 55 7 23 7 – – 4 4 – 100 ko a – j 55 10 12 3 2 10 1 7 – 100 ko b – m 55 19 13 5 – – 5 3 – 100 ko b – j 50 6 15 2 2 10 5 10 – 100 nt a (s) 56 21 11 3 – – 4 – 5 100 nt b (s) 58 31 5 3 – – 3 – – 100 ko a (s) 63 26 8 – – – – – 3 100 ko b (s) 45 5 25 10 2 – 10 3 – 100 m – fly ash for month may; j – fly ash for month june; (s) – slag; am – the amorphous material; q – quartz; f – feldspar; m – mullite; ml – melilite; an – anhydrite; cr – cristobalite; he – hematite; cao – calcite; nt – nikola tesla; ko – kostolac table 4. correlation between physical, chemical and mineral composition of fly ash and slag used from the power plants. symbol significant correlation coefficient values with: fly ash slag chemical composition loi sio2(0.24) al2o3(0.46) cr(0.72) sio2(0.99) al2o3(0.99) cr(0.99) sio2 q(0.53) k2o(0.83) cao(0.85) so3(0.93) mgo(0.97) he(0.82) r(0.48) w(0.42) am(0.21) q(0.31) k2o(0.83) cao(0.48) so3(0.99) mgo(0.30) he(0.20) r(0.74) w(0.75) am(0.97) al2o3 so3(0.86) cao(0.83) fe2o3(0.71) mgo(0.29) m(0.76) ml(0.59) he(0.49) r(0.84) w(0.83) <2.9(0.64) am(0.18) so3(0,99) cao(0.58) fe2o3(0.98) mgo(0.99) m(0.99) ml(0.41) he(0.41) r(0.57) w(0.61) <2.9(0.99) am(0.97) fe2o3 q(0.74) sio2(0.76) al2o3(0.60) r(0.90) q(0.95) sio2(0.92) al2o3(0.92) r(0.73) cao so3(0.66) mgo(0.47) sio2(0.59) q(0.59) k2o(0.79) al2o3(0.45) na2o(0.60) r(0.97) w(0.30) <2.9(0.48) am(0.80) so3(0.73) mgo(0.61) sio2(0.99) q(0.96) k2o(0.24) al2o3(0.70) na2o(0.07) r(0.59) w(0.80) <2.9(0.71) am(0.93) so3 cao(0.91) mgo(0.26) sio2(0.96) al2o3(0.86) q(0.52) cao(0.56) mgo(0.99) sio2(0.99) al2o3(1.00) q(0.36) mgo cao(0.34) so3(0.59) sio2(0.30) al2o3(0.28) r(0.37) cao(0.84) so3(0.92) sio2(0.89) al2o3(0.93) r(0.82) na2o cao(0.47) he(0.34) ph(0.43) f(0.49) cao(0.82) he(0.38) ph(0.99) f(0.45) k2o q(0.69) sio2(0.68) cao(0.49) he(0.90) r(0.77) w(0.16) <2.9(0.47) am(0.57) q(0.48) sio2(0.82) cao(0.84) he(0.53) r(0.99) w(0.99) <2.9(0.68) am(0.98) r he(0.75) sio2(0.56) al2o3(0.50) k2o(0.84) am(0.72) w(0.31) fe2o3(0.79) <2.9(0.42) mgo(0.61) ph(0.32) cao(0.98) q(0.64) cr(0.43) he(0.53) sio2(0.99) al2o3(0.81) k2o(0.98) am(0.92) w(0.99) fe2o3(0.92) <2.9(0.66) mgo(0.52) ph(0.81) cao(0.54) q(0.63) cr(0.93) mineral composition am sio2(0.40) k2o(0.40) al2o3(0.18) cao(0.82) cr(0.78) he(0.36) ml(0.24) <63(0.53) r(0.76) sio2(0.98) k2o(0.16) al2o3(0.91) cao(0.96) cr(0.99) he(0.92) ml(0.92) <63(0.66) r(0.28) q sio2(0.53) k2o(0.70) cao(0.65) so3(0.58) fe2o3(0.58) ml(0.09) <63(0.67) r(0.67) sio2(0.99) k2o(0.41) cao(0.98) so3(0.75) fe2o3(0.94) ml(0.93) <63(0.31) r(0.66) f na2o(0.21) na2o(0.27) m al2o3(0.78) <2.9(0.61) <63(0.59) al2o3(0.94) <2.9(0.63) <63(0.63) ml ph(0.56) q(0.69) am(0.40) al2o3(0.37) fe2o3(0.74) ph(0.68) q(0.99) am(0.99) al2o3(0.92) fe2o3(0.99) cr loi(0.71) am(0.73) ph(0.69) r(0.56) loi(0.99) am(0.99) ph(0.68) r(0.26) he fe2o3(0.98) w(0.10) na2o(0.80) am(0.37) k2o(0.96) sio2(0.82) al2o3(0.89) ph(0.24) r(0.90) fe2o3(0.99) w(0.65) na2o(0.50) am(0.99) k2o(0.48) sio2(0.94) al2o3(0.92) ph(0.68) r(0.53) physical composition ph na2o(0.47) fe2o3(0.24) kr(0.70) he(0.41) ml(0.58) r(0.40) na2o(0.99) fe2o3(0.99) kr(0.99) he(0.25) ml(0.25) r(0.97) w cao(0.65) k2o(0.33) al2o3(0.80) sio2(0.44) he(0.08) r(0.74) cao(0.97) k2o(0.78) al2o3(0.36) sio2(0.65) he(0.34) r(0.96) <2.9 w(0.39) cao(0.55) k2o(0.63) al2o3(0.43) m(0.75) r(0.58) w(0.63) cao(0.47) k2o(0.77) al2o3(0.99) m(0.99) r(0.63) <63 m(0.60) am(0.56) q(0.59) m(1.00) am(0.98) q(0.41) loi 1000 – loss on ignition 1000 °c; r – module r; am – the amorphous material; q – quartz; f – feldspar; m – mullite; ml – melilite; cr – cristobalite; he – hematite; ph – ph values; w – humidity of the sample; <2.9 – density of less than 2.9g/cm3; <63μm – fraction of less than 63μm g eologia c roatica šešlija et al.: properties of fly ash and slag from the power plants 323 results, a total of 266 correlations were made (133 for fly ash and 133 for slag), wherein the positive correlations are shown in bold and negative correlations are italic. positive and negative correlation coefficients for all the tested dependencies are equally represented. during the analysis of the results, absolute values of the correlation coefficients are observed in order to achieve easier comparative analysis of the test samples. a significantly large number of dependencies has been achieved with chemical properties, and then with mineral and finally with physical properties. the research results are compared with each other and shown in the histogram (fig. 6), from which the frequency of correlation coefficients, the mean value of the analyzed results, standard deviation and the number of tested samples can be observed. from the histogram for fly ash, it can be seen that in the range of 0.20 to 0.90 there is approximately an equal number of correlation coefficients except for the coefficient of 0.60, where there is a higher amount of correlation coefficients. the histogram of slag results shows a small representation of the correlation coefficients untill 0.60, then small jumps appear with approximate values, while a large dispersion of correlation coefficients is observed from 0.9 to 1.0. 6. conclusion based on the obtained research results it is evident that the sepower plants use two different coal basins, ie. a different type of combustion coal, and based on that different values of the chemical, mineral and physical compositions are obtained. from the entire study the following conclusions can be drawn: – fly ash and slag have variable chemical, mineralogical and physical properties, and depend on the natural composition and quality of coal for each specific coal basin, – dependencies between the chemical, mineral and physical properties make a good basis for predicting and solvingspecific technological and ecological problems related to the use of ash and slag, – using different types of coal from kolubara and kostolac basins, fairly good correlation coefficients for test samples of fly ash and slag were obtained, – from the analyzed dependencies and presented results of the correlation coefficients, it can be concluded that slag has much better values between the achieved dependencies (physical properties, chemical and mineral composition), except for the case of sio2 where it is noticeable that fly ash has a higher values of the correlation coefficients. references đorđević, m. (2012): geohemijska analiza tragova metala riblje gline s lokaliteta kirkevig (stevns klint, danska) [geochemical analysis of trace metals of fish clay from locality kirkevig (stevns klint, denmark) – in serbian, with an english abstract].– unpubl. phd thesis, faculty of sciences, university of niš, 38 p. en 451-2 (1994): method of testing fly ash – part 2: determination of fineness by wet sieving. en 933-1 (1997): tests for geometrical properties of aggregates – part 1: determination of particle size distribution – sieving method. en 1097-7 (1999): tests for mechanical and physical properties of aggregates – part 7: determination of the particle density of filler – pyknometer metod. en 1328-1 (2003): unbound and hydraulically bound mixtures – part 1: test methods for laboratory reference density and water content – introduction, general requirements and sampling. kezović, m. (2011): coal bearing in kolubara basin.– the journal of the public enterprise electric power industry of serbia, 64, 154–163. (in serbian with english abstract) kim, b., prezzi, m. & salgado, r. (2005): geotechnical properties of fly and bottom ash mixtures for use in highway embankments.– journal of geotechnical and geoenvironmental engineering, 131/7, 914–924. miletić, s. & ilić m. (2007): korišćenje elektrofilterskog pepela u građenju i građevinskim materijalima.– association of civil engineers and technicians of serbia, belgrade. srps b.h8.359 (1973): methods of analysis of coal and coke – determination of chemical composition of fuel ash – general requirements. srps b.h8.360 (1973): methods of analysis of coal and coke – determination of silica (sio2) in ash from solid fuels. srps b.h8.361 (1973): methods of analysis of coal and coke – determination of barium oxide (bao) in ash from solid fuels. srps b.h8.362 (1973): methods of analysis of coal and coke – determination of ferric oxide (fe2o3) in ash from solid fuels. srps b.h8.363 (1973): methods of analysis of coal and coke – determination of titanium oxide (tio2) in ash from solid fuels. srps b.h8.364 (1973): methods of analysis of coal and cokedetermination of aluminum oxide (al2o3) in ash from solid fuels. srps b.h8.365 (1973): methods of analysis of coal and coke – determination of calcium oxide (cao) in ash from solid fuels. srps b.h8.366 (1973): methods of analysis of coal and coke – determination of magnesium oxide (mgo) in ash from solid fuels. srps b.h8.367 (1973): methods of analysis of coal and coke – determination of manganese oxide (mn3o4) in ash from fuels. srps b.h8.368 (1973): methods of analysis of coal and coke – determination of sodium and potassium oxide (na2o2 and k2o) in ash from solid fuels. srps b.h8.369 (1973): methods of analysis of coal and coke – determination of sulfur trioxide (so3) in ash from solid fuels. srps b.h8.327 (1989): solid mineral fuels – determination of phosphorus content – reduced molybdophosphate photometric method. srps u.b1.018 (2005): testig soils – determination of particle size distribution. sprs h.c8.209 (1989): pigments and extenders – determination of ph – value of an aqueous suspension. stojanović, k., životić, d., šajnović, a., cvetković, o., nytoft, h.p. & scheeder, g. (2012): drmno lignite field (kostolac basin, serbia): origin and palaeoenvironmental implications from petrological and organic geochemical studies.– journal of the serbian chemical society, 77/8, 1109–1127. figure 6. histogram of fly ash and slag results (stdev – standard deviation; n – number of samples). g eo lo gi a c ro at ic a geologia croatica 69/3324 thomas, m. (2007): optimizing the use of fly ash in concrete, portland cement association, 1–24. vassilev, s., baxter, d., anderson, l. & vassilev, c. (2013): an overview of the composition and application of biomass ash. part 1. phase-mineral and chemical composition and classification.– fuel, 105, 40–76. vassilev, s., baxter, d. & vassilev, c. (2014): an overview of the behaviour of biomass during combustion: part ii. ash fusion and ash formation mechanisms of biomass types.– fuel, 117, 152–183. vassilev, s., menendez, r., alvarez, d., diaz-somoano, m. & martinez-tarazona, r. (2003): phase-mineral and chemical composition of coal fly ashes as a basis for their multicomponent utilization. 1. characterization of feed coals and fly ashes.– fuel, 82, 1793–1811. vassilev, s., menendez, r., alvarez, d., diaz-somoano, m. & martinez-tarazona, r. (2004a): phase-mineral and chemical composition of coal fly ashes as a basis for their multicomponent utilization. 2. characterization of ceramic cenosphere and salt concentrates.– fuel, 83, 585–603. vassilev, s., menendez, r., borrego, a., diaz-somoano, m. & martinez-tarazona, r. (2004b): phase-mineral and chemical composition of coal fly ashes as a basis for their multicomponent utilization. 3. characterization of magnetic and char concentrates.– fuel, 83, 1563–1583. vassilev, s. & menendez, r. (2005): phase-mineral and chemical composition of coal fly ashes as a basis for their multicomponent utilization. 4. characterization of heavy concentrates and improved fly ash residues.– fuel, 84, 973–991. vassilev, s. & vassileva, c. (2007): a new approach for the classification of coal fly ashes based on their origin, composition, properties, and behavior.– fuel, 86, 1490–1512. ward, c. & french, d. (2005): relation between coal and fly ash mineralogy, based on quantitative x-ray diffraction methodos. 2005 world of coal ash, international symposium, april 11–15, 2005, 1–14. životić, d., bechtel, a., sachsenhofer, r., gratzer, r., radić, d., obradović, m. & stojanović, k. (2015): reprint of „petrological and organic geochemical properties of lignite from the kolubara and kostolac basins, serbia: implication on grindability index”.– international journal of coal geology, 157, 165–183. životić, d., stojanović, k., gržetić, i., jovančićević, b., cvetković, o., šajnović, a., simić, v., stojaković, r. & scheeder, g. (2013): petrological and geochemical composition of lignite from the d field, kolubara basin (serbia).– international journal of coal geology, 111, 5–22.  distribution of chemical elements in soil samples from the pelagonia region, republic of macedonia  ana puteska1, bojana dimovska1, robert šajn2* and trajče stafilov1 1 institute of chemistry, faculty of natural sciences and mathematics, ss cyril and methodius university in skopje, pob 162, 1000 skopje, republic of macedonia 2 geological survey of slovenia, ljubljana, slovenia; (robert.sajn@geo-zs.si) doi: 10.4154/gc.2015.20 abstract this study represents the first systematic investigation of the spatial distribution of different chemical elements in the soil cover of the pelagonia region, republic of macedonia. for this purpose, 262 soil samples (from 131 locations) were analyzed to determine the content of 17 major and trace elements in the soil from this region and to assess the size of the area eventually affected by heavy metal pollution. all samples were analyzed by atomic emission spectroscopy with inductively coupled plasma (icp-aes). cluster and factor analysis (r-mode) were applied in order to show the associations of chemical elements. three factors were obtained. factor 1 (al, ba, mg, mn, fe, ni, p and v), factor 2 (cr, cu, pb and zn) and factor 3 (ca and sr). it was established that the distribution of these associations are mostly as a result of the complex geology and lithology of the region. keywords: soil, pelagonia region, republic of macedonia, multivariate statistics, geochemical mapping 1. introduction urban pollution with heavy metals is a global problem initiated by the world’s technological progress and human exploitation of natural resources, and as such has become the subject of many studies. the regional contamination of soil occurs mainly in industrial areas and within centres of large settlements, where factories, motor vehicles and municipal wastes are the most important sources of trace metals (kabata-pendias & pendias, 2001). the level of environmental pollution will depend on the proper control of anthropogenic activities such as well extraction, the concentration and separation of waste (qin et al., 2012). the major causes of emissions are anthropogenic sources specifically mining operations (hutton and symon, 1986; battarbee et al., 1988; nriagu, 1989). in some cases, even long after mining activities have ceased, the emitted metals continue to persist in the environment (peplow, 1999). the potential for contamination is increased when mining exposes metal-bearing ores rather than the natural exposure of ore bodies through erosion (garbarino et al., 1995). heavy metals occur as natural constituents of the earth’s crust, and are persistent environmental contaminants since they cannot be degraded or destroyed. some heavy metals have bio-importance as trace elements but, the biotoxic effects of many of them in human biochemistry are of great concern. hence, there is the need for proper understanding of the conditions, such as the concentrations and oxidation states, which make them harmful, and how biotoxicity occurs (duruibe et al., 2007). the republic of macedonia has the same problem with global pollution by heavy metals (stafilov et al., 2009; stafilov, 2014). recent results obtained from previous studies, suggest that the most important emission sources are mines and drainage systems and smelters near the towns of veles, tetovo, kavadarci and radoviš, in addition to some geologia croatica 68/3 261–272 7 figs. 6 tabs. zagreb 2015 geologia croaticageologia croatica geologia croatica 68/3geologia croatica 262 2. study area the pelagonia valley is located in the south-southwest of the republic of macedonia, meeting the border with the republic of greece at its southern part. geographically, pelagonia lies between the following coordinates: north-south: 41° 30' – 40° 50'; east-west: 21° 50' – 20° 50' (fig. 1). pelagonia is the largest macedonian valley, and includes the environs of bitola, prilep and demi hisar. the pelagonia region lies between 550 and 900 m above sea level in the low areas, up to 2601 m a.s.l. at pelister, on mount baba, the highest peak in the region. kruševo and the area around the city are at an altitude of 1,200 m. the climate in the region is a modified continental or moderate continental one, with hot and dry summers, and cold and wet winters in some micro-regions and a mediterranean climate elsewhere. the annual amount of precipitation ranges from 570 mm in the region of prilep to 915 mm per year in the district of kruševo. the temperature range is large and large temperature fluctuations are persistent throughout the year. maximum summer temperature reach 40 °c, and the minimum winter temperatures drop to -30 °c, while the average annual temperature is slightly above +10 °c. these climatic conditions are typical for aridic and semiaridic areas (lazarevski, 1993). the region is the most important agricultural region in the country as it produces 50% of the total tobacco producuranium deposition patterns which were described by the activity of power plants using lignite coal as fuel (stafilov et al., 2010a, 2010b; barandovski et al., 2012; balabanova et al., 2010, 2011; bačeva et al., 2012). the soil cover of the republic of macedonia is very heterogeneous, with great changes over small distances. almost all relief forms, geological formations, climatic influences, plant associations and soils that appear in europe (with the exception of podzols) are represented. more than thirty soil types are found in macedonia (mitkova & mitrikeski, 2005). degradation of soils in macedonia began a long time ago (filipovski, 2003). some hotspots are enriched in soil pollution with heavy metals (stafilov et al., 2009; stafilov, 2014). plants near the hotspots accumulate heavy metals directly from the soil or from the air, which are passed through them to man and animals (filipovski, 2003). disposal of fly ash and slag from thermoelectric power plants using coal also degrades the environment, especially soils. the purpose of this research was to determine the level of soil contamination with heavy metals in the pelagonia valley, republic of macedonia, mostly as a result of the impact of the thermoelectric power plant “bitola” situated near the city of bitola, as well as from traffic and industrial activities in the cities in the valley (bitola, prilep, demir hisar and kruševo) and their environs. figre 1: study area. puteska et al.: distribution of chemical elements in soil samples from the pelagonia region, republic of macedonia geologia croatica 263 tion in macedonia and 30% of the wheat production. other important agricultural products grown in this region include vegetables, corn, sugar beet, grapes and oilseed crops such as sunflower. in this context it should be emphasized that there is a relatively well developed livestock industry. most of the industries are located in major cities such as bitola and prilep. this sector is in development, with a particular rise in industries centred around architectural building stone, food, alcoholic and non-alcoholic beverages, processing, and printing. in addition, the thermoelectricpower plant near bitola produces about 70% of the total electricity production in macedonia. this power plant constantly creates large amounts of waste in the form of ash and slag, explained by the fact that in one year the mining and energy combine (cem) “bitola” consumes 6.5 million tons of lignite. lignite is low quality: it contains relatively few calories and produces much ash: from 13.4 to 16.3% (trajkovska & vrencovski, 2001). the fly ash and slag are present and include heavy metals: mn, cr, ni and pb (biljanovska et.al., 1996). 3. geologic description the pelagonia valley, according to the geology, belongs to two tectonic units: the pelagonian massif and the west macedonian zone, each of which is characterized by its tectonic history. tectonic processes at different stages exhibited different intensities, which is the main feature of each tectonic unit. in the western part of macedonia, the dinarides (helenites) were defined on these principles (arsovski, 1997). within the dinarides, the following separate tectonic zones are defined from w-e: the vardar zone, pelagonian horst-anticlinorium, westernmacedonian (šara-pelister) zone and cukali-crasta zone (see fig. 2 for the geology). pelagonia massif or pelagonian horst-anticline. the pelagonia horst–anticline represents a relict of the precambrian and prebaikal earth’s crust in this part of helenitedinaridеs. pelagonia as a horst, is characterized by separation from the neighboring tectonic units on all sides by regional faults and depth. the geological structure of the pelagonian massif is divided into two parts: north and south. the ridge line pletvar-sivec-debrešte is a natural border between the northern and southern parts of pelagonia, well expressed at the contact between the marble and gneisses in the area of pletvar and the marble and micashists in the area of sivec. towards the west it is covered with neogene quaternary sediments. in the southern part of pelagonia, the prilep granite massif includes highly metamorphic rocks, gneiss, micashists, marble etc. a large amount of magmatic rocks are represented with granites (arsovski, 1997). a series of marbles is very well preserved and expressed. the lower horizon is dominated by dolomite and dolomitic marble but the upper layer is represented by calcite marble (boev, 2006). the coal layers are well developed in the eastern part of the gravel, and thin in the west and north (andreevski, 1990). the upper unit, consisting of diatomite, siltstone, and claystone, has been well studied in the southern part of the graben from outcrops and in the suvodol coal mine. in the bitola area, there is a 70 m continuous section (dumurdzanov, 1997). during the neogene, pliocene lake sediments accumulated, represented by sandy, marled and carbonized clays, marls and fine grained sandstone with the total thickness exceeding 100 m (stojanović, 1989). granitoid rocks and their core differentials represent an important part of the pelagonia horstanticlinorium in the south (gapkovki & jovanovski, 2007). prilep granodiorite-adamelite is a massive, light gray, coarse, felsic rock (stojanov, 1974). quaternary sediments are present over the entire pelagonian graben. they consist of alluvial and proluvial sediments (dumurdzanov et al., 2004). the pelagonian formation consists of ~600 m of terrigenous coal-bearing strata that can be divided into three superposed lithological units. the basal unit consists of gravel, sandstone and silty claystone. the middle coal-bearing unit consists of interbedded siltstone, silty claystone and a few coal-bearing layers. the coal layers are well developed in the eastern part but much less at the west and north (andreevski, 1990). the upper unit consisting of diatomite, siltstone, and claystone (dumurdzanov, 1997). figure 2: geological map of pelagonia valley. geologia croatica 68/3geologia croatica 264 the west-macedonian zone was defined by arsovski (1960). according to the magmatic characteristics, the westmacedonian zone can be divided into two subzones: an eastern dominated acidic granite magmatic province and a western zone dominated by alkaline and ultra-alkaline rocks (arsovski, 1997; dumurdzanov, 1997). the west– macedonian zone represents an inner massif in the northeastern part of the hellenides, mostly built of old palaeozoic formations, which is intensively dislocated together with the formation of the early alpine roof. the area of the west-macedonian zone is divided into five segments (arsovski, 1990). the west macedonian zone (zm) is represented by several lithostratigraphic formations. the oldest vulcanogenic formation is represented by palaeozoic spilites and keratophyres. elsewhere there is a series of phyllites and marble. the lower caledonian complex in the west-macedonian zone is represented by green schists. on the eastern slopes of mount buševa, lower caledonian formations at the base are represented by quartz-sericite schists, as well as above the green schist formation. granites are also prevalent in the caledonian complex (dumurdzhanov et. al., 2004). 4. material and methods 4.1. sampling samples of natural surface soils in the pelagonia valley were collected according to the european guidelines for soil pollution studies (theocharopoulos et. al. 2001), and also according to our experience (šajn, 2003, 2005, 2006; stafilov et al., 2008a; 2008b). the study area (3100 km2) is covered by a sampling grid of 5×5 km2 (fig. 3). at 131 sampling sites 262 soil samples were collected attwo soil horizons, topsoil (0-5) and subsoil (20-30 cm), respectively. any possible organic horizon was excluded. one sample represents a composite sample collected at the central sample point itself, and with materials from at least four points within a 10 m radius towards the north, east, south and west. the mass of the composite sample was about 1 kg. at each location where soil samples were collected, location characteristics (geographic coordinates and altitude) were recorded using a global positioning system. such positioning, i.e. determining of the position of sample locations is necessary in order to construct the distribution of each metal in the study area. figure 3: soil samples locations in pelagonia valley. puteska et al.: distribution of chemical elements in soil samples from the pelagonia region, republic of macedonia geologia croatica 265 4.2. sample preparation the soil samples were air dried indoors at room temperature for about two weeks. then they were gently crushed, cleaned of extraneous material and passed through a plastic sieve with 2 mm mesh (salminen et al., 2005). the sifted mass was quartered and milled in an agate mill for an analytical grain size below 0.125 mm. for the digestion of soil samples, open wet digestion with a mixture of acids was applied. a 0.25 g ( +/0,0001g) sample was placed in a teflon vessel. 5 ml of concentrated nitric acid (hno3) was added, until the brown vapours were released indicating oxidation of organic matter in the samples. for total digestion of the inorganic components, 5–10 ml hydrofluoric acid (hf) was added. when the digestion became a clear solution, 2 ml of hclo4 was added. perchloric acid was used for total digestion of organic matter. after cooling the vessels for 15 min, 2 ml of hcl and 5 ml of h2o were added to aid the total dissolution of the metal ions. finally, the vessels were cooled and the digestions quantitatively transferred to 50 ml calibrated flasks (stafilov et al., 2008a; 2010b; balabanova et al., 2011). 4.3. instrumentation analysis of the digested samples was performed using atomic emission spectrometry with inductively coupled plasma (icp-aes). optimization of the instrumental conditions for each element was published in balabanova et al., (2010). in total, 17 elements were analyzed from the collected samples: al, ba, ca, cr, cu, fe, k, li, mg, mn, na, ni, p, pb, sr, v and zn. the quality control/quality assurance (qa/qc) of the three applied techniques was performed by standard addition method, and it was found that the recovery for the investigated elements ranges from 98.2 % – 100.8 %. 4.4. data processing data analysis and the production of maps were performed on a pc using the paradox (ver. 9), statistica (ver. 6.1), autodesk. (ver. 2008) and surfer (ver. 8.09) software. all field observations, analytical data and measurements were introduced into the data matrix. for each observation there are 45 variables: sample identification number, sampling material type, geographic coordinates (x, y, z), type of analysis, land use, basic lithological units, level of soil pollution and the determination of the 17 analyzed elements (al, ba, ca, cr, cu, fe, k, li, mg, mn, na, ni, p, pb, sr, v and zn) with the icp-aes method (n = 262). parametric and nonparametric statistical tests were performed on the data (snedecor, 1976; davis, 1986). on the basis of the results of the normality tests and visual inspection of the distribution histograms, logarithms of the element content were used for all elements. the basic statistical data for the 17 selected chemical elements (al, ba, ca, cr, cu, fe, k, li, mg, mn, na, ni, р, pb, sr, v and zn) and the average of elements with regards to the basic lithological units in the topsoil are shown in tables 1 and 2. multivariate r-mode factor analysis (snedecor & cochran, 1967; davis, 1986) was used to reveal the associations of the chemical elements. from numerous variables, the factor analysis (fa) derives a smaller number of new, synthetic variables. the factors contain significant information about the original variables, and they may have particular meaning. factor analysis was performed on variables standardized to zero mean and unit of standard deviation (reimann et al., 2002). as a measure of the similarity between variables, the product-moment correlation coefficient (r) was applied. for orthogonal rotation, the varimax method was used. the universal kriging method with linear variogram interpolation (snedecor, 1976) was applied for construction of the areal distribution maps of the 17 selected elements and the factor scores (f1–f3) in topsoil (0–5 cm) and subsoil (20-30 cm) samples. the basic grid cell size for interpolation was 20×20 m. for class limits the percentile values of the factor scores distribution of the interpolated values were chosen. seven classes of the following percentile values were selected: 0–10, 10–25, 25–40, 40–60, 60–75, 75–90 and 90– 100. 5. results and discussion the distributions of elements that reflect natural processes are indicated by elements that are rarely or never included in industrial processes. their contents usually change gradually across the landscape and depend on the geological background. data from the descriptive statistics of measurements for topsoil and subsoil samples from 131 locations (in total 262 soil samples) are presented in tables 3 and 4. values of al, ca, fe, k, mg and na are in %, and remaining elements in mg/kg. an analysis of the soil samples gives data for the content of 17 elements (al, ba, ca, cr, cu, fe, k, li, mg, mn, na, ni, p, pb, sr, v, zn). in tables 1 and 2 the following statistical parameters are given: x – arithmetic average x(bc) – arithmetic average after box-cox method, md median, min – minimum, max maximum, p10 10 percentile, p90 90 percentile, p25 25 percentile, p75 75 percentil, ѕ – standard deviation, ѕx – standard error, cv – coefficient of variation, a –skewness; е – kurtosis, вс – вох-сох transformed values. the box-cox transformation has proved their superiority compared to normal values (untransformed data) or logarithmic transformation because the skewness and kurtosis are significantly improved. the criteria of normal distribution that might be used later in multivariate statistical methods are better satisfied by using boc-cox transformations. in order to determine the dependence of the average contents (box cox) of the analyzed elements between the topsoil and the subsoil, the ratio of the contents was calculated (table 3). the elements distribution should not vary significantly between the topsoil (0–5 cm) and the subsoil (20–30 cm), except if certain destructive anthropogenic or natural processes contribute to the variation of the concentration (dudka & adriano, 1997). for almost all elements, non-significant differences were received for their content geologia croatica 68/3geologia croatica 266 table 1: descriptive statistics of measurements for topsoil samples (n = 131). values of al, ca, fe, k, mg and na are in %, remaining elements in mg/kg. element material unit x x (bc) md min max p10 p90 p25 p75 s cv a e a (bc) e (bc) al topsoil % 2.1 2.0 1.9 0.46 6.2 0.96 3.3 1.3 2.8 1.1 50.3 1.06 1.46 0.22 –0.25 ba topsoil mg/kg 560 510 470 72 1700 280 1000 350 680 290 52.8 1.31 1.79 0.31 0.24 ca topsoil % 1.6 0.76 0.78 0.091 32 0.26 2.0 0.44 1.3 3.6 230.7 6.33 45.05 0.08 0.99 cr topsoil mg/kg 100 74 74 16 650 33 200 49 120 98 94.7 2.92 10.75 0.01 –0.06 cu topsoil mg/kg 20 16 17 0.30 120 3.4 37 9.0 29 17 82.8 2.45 10.15 –0.04 0.62 fe topsoil % 2.7 2.4 2.4 0.79 16 1.3 4.2 1.6 3.4 1.7 61.7 4.33 32.73 0.28 1.07 k topsoil % 1.7 1.7 1.8 0.22 3.1 1.0 2.4 1.3 2.1 0.57 32.8 –0.04 –0.08 –0.06 –0.07 li topsoil mg/kg 18 16 15 3.7 93 6.8 33 10 23 13 69.1 2.51 10.02 0.35 0.26 mg topsoil % 0.53 0.50 0.50 0.074 1.6 0.23 0.89 0.32 0.69 0.27 50.8 0.86 0.92 0.10 –0.17 mn topsoil mg/kg 640 590 580 170 2200 320 1000 440 790 310 48.4 1.80 5.60 0.28 0.73 na topsoil % 1.3 1.2 1.2 0.056 3.7 0.39 2.1 0.69 1.8 0.71 55.5 0.50 0.18 –0.05 –0.44 ni topsoil mg/kg 30 27 27 3.2 76 9.1 53 16 42 17 56.8 0.65 –0.10 0.04 –0.62 p topsoil mg/kg 530 430 440 59 3500 190 870 250 670 430 81.1 3.86 22.09 0.06 0.79 pb topsoil mg/kg 60 19 22 2.5 2300 5.0 55 10 31 240 396.8 7.92 66.16 0.34 0.97 sr topsoil mg/kg 110 91 95 14 420 38 190 56 140 75 67.9 1.95 4.87 –0.03 0.06 v topsoil mg/kg 80 74 73 17 260 34 130 51 100 42 51.8 1.27 2.88 0.22 0.16 zn topsoil mg/kg 160 56 53 1.4 4700 13 230 25 120 530 320.9 7.18 55.52 0.33 1.68 n – number of samples; x – mean; х(вс) – mean of вох-сох transformed values; mеd – median; min – minimum; max – maximum; p25 – 25th percentile; p75 – 75th percentile; ѕ – standard deviation; ѕх – standard deviation of transformed values; cv – coefficient of variation, а – skewness; е – kurtosis; вс – вох-сох transformed values table 2: descriptive statistics of measurements for subsoil samples (n = 131). values of al, ca, fe, k, mg and na are in %, remaining elements in mg/kg. element material unit x x (bc) md min max p10 p90 p25 p75 s cv a e a (bc) e (bc) al subsoil % 2.1 2.0 2.1 0.14 4.9 0.99 3.4 1.3 2.7 0.96 45.8 0.58 –0.03 –0.25 0.13 ba subsoil mg/kg 570 520 470 15 1500 290 1000 360 740 310 53.2 1.05 0.65 –0.14 1.34 ca subsoil % 1.3 0.71 0.76 0.067 22 0.26 1.9 0.44 1.2 2.6 200.2 6.31 44.09 –0.22 1.33 cr subsoil mg/kg 98 73 74 16 540 33 180 49 110 87 89.1 2.96 10.45 –0.03 0.38 cu subsoil mg/kg 20 16 16 1.3 110 4.6 35 9.0 28 15 76.8 2.33 10.81 0.09 0.26 fe subsoil % 2.7 2.4 2.5 0.32 15 1.3 4.0 1.8 3.3 1.5 55.2 3.99 30.11 –0.26 2.25 k subsoil % 1.8 1.8 1.8 0.041 3.4 1.1 2.5 1.4 2.1 0.56 31.5 0.07 0.18 0.04 0.20 li subsoil mg/kg 19 16 16 0.66 94 8.2 33 11 23 13 68.0 2.57 10.39 –0.26 2.54 mg subsoil % 0.53 0.49 0.49 0.049 1.4 0.22 0.84 0.33 0.67 0.26 50.1 0.84 1.10 –0.10 0.26 mn subsoil mg/kg 630 580 570 54 2000 340 1000 460 740 290 45.6 1.52 3.88 –0.19 2.23 na subsoil % 1.3 1.2 1.3 0.007 3.7 0.37 2.2 0.73 1.7 0.70 54.6 0.44 0.24 –0.16 –0.28 ni subsoil mg/kg 31 28 29 0.094 93 10 54 17 43 18 57.9 0.76 0.66 –0.12 –0.03 p subsoil mg/kg 500 400 430 46 3500 170 870 250 630 420 82.9 3.90 23.53 –0.03 0.78 pb subsoil mg/kg 29 19 24 2.5 210 5.0 49 12 34 28 99.3 3.48 17.16 –0.54 –0.30 sr subsoil mg/kg 110 90 93 15 370 43 170 62 130 71 65.6 1.87 3.91 0.03 0.26 v subsoil mg/kg 81 75 75 3.4 260 41 130 54 99 38 47.0 1.26 3.72 –0.15 1.42 zn subsoil mg/kg 92 51 55 0.87 780 12 200 26 110 120 134.4 3.66 16.55 –0.46 0.89 n – number of samples; x – mean; х(вс) – mean of вох-сох transformed values; mеd – median; min – minimum; max – maximum; p25 – 25th percentile; p75 – 75th percentile; ѕ – standard deviation; ѕх – standard deviation of transformed values; cv – coefficient of variation, а – skewness; е – kurtosis; вс – вох-сох transformed values thropogenic activities. this is also confirmed by great similarity in the spatial distribution of the investigated elements in the topsoil and subsoil samples. in the topsoil versus subsoil. thus, this relationship varies from 0.97 for ni to 1.10 for zn which shows the absence of the significant influence of possible soil pollution from anputeska et al.: distribution of chemical elements in soil samples from the pelagonia region, republic of macedonia geologia croatica 267 the order of the distribution of the concentration data of major elements al, ca, fe, k, mg, na, ti are in the following ranges: 0.14–6.2% al; 0.07–32% ca; 0.32–16% fe; 0.04–3.4 k; 0.05–1.6% mg and 0.01–3.7% na. the con tents of major elements are most frequently a result of the dominant geological formations of the area: quaternary sediments, precambrian and palaeozoic schists and gneisses, volcanic rocks and palaeozoic and mesozoic carbonates. a comparative analysis (table 4) was conducted based on the data of the contents of different chemical elements in the soils in europe, provided by salminen et al. (2005). for the comparative analysis, the values of the medians were used as they are a more stable parameter. the al and na contents are lower in relation to the data published by salminen et al. (2005), while for the other macro-elements, including phosphorus and manganese, the values did not show any significant variations. the distribution of the remaining chemical elements characteristically corresponds to the lithogenic origin of the rocks in the separate subregions of the area (fig. 2). the only big difference is in the content of lead, which is two times greater in the topsoil and 1.5 times larger in subsoil samples than the european values. the values of the medians of the investigated elements in soil from the pelagonia region were found to be similar to those of soil samples collected from the whole of the territory of macedonia (mihajlov et al., 2013; mihajlov, 2014), table 4. there are slightly higher contents of cr, k, na and sr in the pelagonian soils than those for macedonian soil and lower content for mg, mn and ni which is a result of the variation in the geology in some parts of macedonia (jovanovski et al., 2012). table 3: average of the elements contents in topsoil and subsoil and their ratio. вох-сох transformed values used. element unit topsoil subsoil topsoil/subsoil al % 2.0 2.0 1.00 ba mg/kg 510 520 0.98 ca % 0.76 0.71 1.07 cr mg/kg 74 73 1.01 cu mg/kg 16 16 1.01 fe % 2.4 2.4 0.98 k % 1.7 1.8 0.98 li mg/kg 16 16 0.98 mg % 0.50 0.49 1.01 mn mg/kg 590 580 1.01 na % 1.2 1.2 1.00 ni mg/kg 27 28 0.97 p mg/kg 430 400 1.07 pb mg/kg 19 19 1.00 sr mg/kg 91 90 1.01 v mg/kg 74 75 0.98 zn mg/kg 56 51 1.10 ta bl e 4: c om pa ris on o f t he m ed ia n va lu es fo r t op a nd su bs oi l s am pl es in p el ag on ia v al le y, m ac ed on ia n an d eu ro pe an v al ue s ( in m g/ kg ). pe la go ni a, 2 01 4 (p re se nt w or k) eu ro pe (s a lm in en e t a l., 2 00 5) m ac ed on ia , 2 01 4 (m ih a jl o v et a l., 2 01 4) el em en t to ps oi l su bs oi l to ps oi l su bs oi l to ps oi l su bs oi l m d m in m ax m d m in m ax m d m in m ax m d m in m ax m d m in m ax m d m in m ax al 19 00 0 46 00 -6 20 00 21 00 0 14 00 4 90 00 58 00 20 00 -1 40 00 62 00 11 00 -1 40 00 2 20 00 79 00 -4 30 00 23 00 0 77 00 -5 10 00 ba 47 0 72 -1 70 0 47 0 15 -1 50 0 38 0 30 -1 90 0 39 0 13 -2 10 0 42 0 41 -1 60 0 44 0 66 -1 70 0 ca 78 00 91 032 00 00 76 00 67 022 00 0 66 00 19 034 00 00 81 00 17 037 00 00 79 00 92 021 00 00 78 00 10 00 -2 10 00 0 cr 74 16 -6 50 74 16 -5 40 60 <3 .0 -6 20 0 62 <3 .0 -2 10 0 54 11 -6 00 63 11 -6 00 cu 17 0. 30 -1 20 16 1. 311 0 13 0. 81 -2 60 14 0. 86 -1 30 16 1. 773 16 3. 278 fe 24 00 0 79 00 -1 60 00 0 25 00 0 32 00 -1 50 00 0 25 00 0 11 00 –1 50 00 0 26 00 0 77 011 00 00 25 00 0 63 00 -6 70 00 27 00 0 77 00 -8 00 00 k 18 00 0 22 00 -3 10 00 18 00 0 41 034 00 0 16 00 0 22 0– 51 00 0 17 00 0 <8 350 00 0 14 00 0 26 00 -3 20 00 15 00 0 52 00 -3 30 00 m g 50 00 74 016 00 0 49 00 49 014 00 0 47 00 <6 1– 15 00 00 60 00 <6 111 00 00 66 00 11 00 -2 90 00 73 00 15 00 -3 10 00 m n 58 0 17 022 00 57 0 54 -2 00 0 51 0 31 -6 10 00 47 0 23 -4 70 0 62 0 16 032 00 64 0 99 -4 30 0 n a 12 00 0 56 037 00 0 13 00 0 70 -3 70 00 60 00 30 033 00 0 65 00 23 036 00 0 85 00 33 023 00 0 94 00 78 024 00 0 n i 27 3. 276 29 0. 09 493 18 <2 .0 -2 70 0 22 <2 .0 -2 40 0 3 5 2. 553 0 37 5. 253 0 p 44 0 59 -3 50 0 43 0 46 -3 50 0 96 0 83 -9 90 0 72 0 53 -1 20 00 45 0 12 014 00 43 0 74 -1 30 0 pb 22 2. 523 00 24 2. 521 0 10 5. 397 0 17 <3 .0 -9 40 17 2. 570 0 14 0. 80 -6 60 sr 95 14 -4 20 93 15 -3 70 89 8. 031 00 95 6. 020 00 71 9. 454 0 68 9. 958 0 v 73 17 -2 60 75 3. 426 0 60 2. 754 0 63 1. 333 0 67 14 -3 00 71 19 -3 70 zn 53 1. 447 00 55 0. 87 -7 80 52 <3 -2 90 0 47 <3 -3 10 0 39 3. 144 0 38 4. 449 0 geologia croatica 68/3geologia croatica 268 because of the great number of variables, that is, different chemical elements whose distribution in the area of the pelagonia region is monitored, data reduction was performed based on the application of a factor analysis. a matrix of correlation coefficients was produced based on previously standardized and box-cox transformed values for the element contents in the samples of topsoil and subsoil (table 5). in the factor analysis, 131 samples of the topsoil (0–5 cm), 131 samples of the subsoil (20–30 cm) and the analysis of 17 chemical elements were considered. from the r-mode factor analysis, 5 chemical elements (ba, k, li and na) were eliminated from further analysis because they have low proportions of communality or a tendency to form independent factors. the geochemical associations of variables were processed based on the basic matrix of correlation coefficients. table 6 shows the loadings of values for each individual element on each factor, showing three geochemical associations. the total communality of the factors amounts to 78.3% (таble 6). in the factor extraction, significantly pronounced associations of elements were taken into consideration only those having an е-value (eingene value) higher than 1 (kaiser’s rule). the e-value, correspondingly for each factor, is presented in table 6. following the results of factor analysis (table 6) and the trends shown on the geochemical maps, three natural geochemical associations in soil have been defined: factor 1 (al, fe, mg, mn, ni, p and v), factor 2 (cr, cu, pb and zn) and factor 3 (cа and sr). identical results were achieved as in the case of application of cluster analysis (the graphical representation is shown in fig. 4). namely, factor 1 (al, fe, mg, mn, ni, p and v) correspond to cluster 1 and cluster 2. the similarity of only 47% between cluster 1 and cluster 2 support the dual origin of the elements of cluster 2 (cr, fe, v and ni), geogenic and lithogenic origin; the classification of cluster 3 (cu, pb and zn) is the same of the results of factor 2 (cr, cu, pb and zn), and cluster 4 is the same as factor 3 (cа and sr). table 5: matrix of correlation coefficients (n = 262, 17 elements). al 1.00 ba –0.24 1.00 ca 0.22 –0.10 1.00 cr 0.29 –0.14 –0.02 1.00 cu 0.26 0.07 0.00 0.43 1.00 fe 0.35 0.19 –0.02 0.32 0.57 1.00 k 0.13 –0.20 –0.33 –0.03 –0.13 –0.22 1.00 li 0.21 –0.08 –0.12 –0.07 0.20 0.19 0.19 1.00 mg 0.66 –0.04 0.09 0.14 0.48 0.43 0.11 0.24 1.00 mn 0.47 –0.08 –0.05 0.18 0.51 0.51 0.09 0.28 0.50 1.00 na –0.15 –0.13 –0.21 –0.31 –0.58 –0.53 0.29 –0.25 –0.30 –0.35 1.00 ni 0.42 0.15 –0.01 0.34 0.65 0.65 –0.05 0.38 0.61 0.61 –0.64 1.00 p 0.39 0.18 0.15 0.15 0.40 0.69 0.00 0.16 0.43 0.41 –0.34 0.44 1.00 pb 0.01 0.01 –0.01 0.36 0.41 0.08 –0.01 –0.05 –0.03 0.07 –0.09 0.05 0.04 1.00 sr 0.44 0.09 0.10 –0.05 –0.18 –0.05 0.04 –0.09 0.39 0.04 0.34 –0.03 0.18 0.02 1.00 v 0.41 0.18 –0.08 0.33 0.57 0.84 –0.15 0.24 0.58 0.56 –0.52 0.74 0.55 0.07 0.08 1.00 zn 0.06 –0.03 0.02 0.45 0.48 0.12 –0.02 –0.06 0.00 0.10 –0.17 0.11 0.06 0.98 –0.02 0.10 1.00 al ba ca cr cu fe k li mg mn na ni p pb sr v zn table 6: matrix of dominant rotated factor loadings (n = 262, 13 selected elements). element f1 f2 f3 com al 0.74 –0.14 0.40 72.5 fe 0.72 0.56 –0.07 83.4 mg 0.86 0.01 0.24 79.2 mn 0.84 –0.03 –0.03 70.3 ni 0.81 0.39 –0.09 81.5 p 0.83 0.17 0.24 77.5 v 0.82 0.37 –0.10 81.9 cr 0.50 0.60 –0.07 62.2 cu 0.43 0.79 –0.08 80.8 pb –0.11 0.90 –0.02 82.5 zn 0.12 0.93 0.00 87.1 ca 0.00 0.13 0.92 86.5 sr 0.22 –0.45 0.69 73.0 eigen val 6.05 2.87 1.26 expl. var 5.02 3.52 1.64 prp. totl 38.6 27.1 12.6 78.3 f1 … f3 – factor loadings; com – communality (%); var – variance (%) puteska et al.: distribution of chemical elements in soil samples from the pelagonia region, republic of macedonia geologia croatica 269 factor 1 (al, fe, mg, mn, ni, p and v) is a lithogenic and geogenic association. the spatial distribution of the elements of this factor is given in fig. 5, both for topand subsoil samples. in the pelagonia valley the maximum content of these elements are in areas with pertinent bedrock geology (fig. 3), occupied by the precambrian and palaeozoic schists and volcanic and magmatic rocks. in demir hisar, these elements are found in a nearby iron mine at the plakenska mountain and continue south to mount baba (fig. 5). the highest iron content occurs in the demir hisar area, where there are abundant iron mines (sopotnica, žvan). a similar behaviour is shown for nickel where the maximum content is observed in the areas of precambrian and palaeozoic schists in the demir hisar area. magnesium is found in the soil on mount baba, and originates from the granite formation where dolomite and amphibole minerals prevail. manganese is mostly distributed in the precambrian and palaeozoic schists of the eastern slopes of the plakenska mountain, around cer where it is assumed that there are deposits of manganese. vanadium is an integral part of the volcanic and magmatic rocks, south of kruševo to demir hisar. figure 4: dendrogram of cluster analysis. figure 5: spatial distribution of factor 1 scores: al, fe, mg, mn, ni, p, v in topsoil (left) and subsoil (right). geologia croatica 68/3geologia croatica 270 figure 7: spatial distribution of factor 3 scores: ca, sr in topsoil (left) and subsoil (right). figure 6: spatial distribution of factor 2 scores: cr, cu, pb, zn in topsoil (left) and subsoil (right). puteska et al.: distribution of chemical elements in soil samples from the pelagonia region, republic of macedonia geologia croatica 271 factor 2 (cr, cu, pb and zn) represents the geogenic association and spatial distribution of the factor scores of this factor for topand subsoil as shown in fig. 6. the origin of these elements belongs to the palaeozoic and mesozoic carbonates and the precambrian and palaeozoic schists. the demir hisar area, where the highest concentrations of lead are present, is geologically composed of acidic volcanic rocks and palaeozoic and precambrian rocks, near the village of strugovo, and in the cer field, which is the only karst field in the study area. the content of zinc is the highest in the area of palaeozoic granitoids and is always in good correlation with the distribution of lead. granite associated zinc deposits are found in limestone rocks known as skarn deposits (dawson, 1996). chromium has lithological nature and is associated with alkaline and ultraalkaline rocks. it was found in the karst field of the village of cer. factor 3 (ca and sr) is a natural factor that depends on the underlying lithology and the spatial distribution of the factor scores of topand subsoil are almost identical (fig. 7). sources of these elements are mainly natural phenomena such as the erosion of rocks, and soil chemical processes. higher contents of these elements are located in areas of quaternary and tertiary sediments and volcanic and magmatic rocks in bitola and demir hisar, and in the prilep region in areas of precambrian gneisses and old granites. 6. conclusion the aim of this study is the systematic investigation of the spatial distribution of various chemical elements in surface soil over the pelagonia region, republic of macedonia. in total 262 soil samples (from 131 locations) were collected and analyzed for 17 major and trace elements. factor analysis with multivariance r-method was applied in order to show the associations of chemical elements and three factors were obtained: factor 1 (al, ba, mg, mn, fe, ni, p and v), factor 2 (cr, cu, pb and zn) and factor 3 (ca and sr). it was established that the distribution of these associations are mostly as a result of the complex geology and lithology of the region. the none obtained factor has not confirmed the correlation to anthropogenic influence, especially with rek bitola. this also happened with soil sampling around rek oslomej – kičevo (stafilov, et al., 2014). it seems that the lignite from this area is clean, with only a very small amount of trace elements which are consequently not recorded in the soil. alternatively, the pollution halos have been determined in moss samples (dimovska, et al, 2014). it seems that the moss is much better sampling material in determination this type of pollution. references andreevski, b. (1990): the qualitative parameters of the coal in sr macedonia as a basis for their classification.– xii kongres geologa jugoslavije, ohrid, vol. iii, 371–382. arsovski, m. (1960): some features of the tectonic structure of the central part of the pelagonia horst-anticline and its relationship with vardar zone.– papers of geological institute of srm, volume 7, skopje (in macedonian). arsovski, m. (1990): some features of the tectonic structure of the central part of the pelagonia horst-anticline and its relationship with vardar zone.– papers of geological institute of srm, volume 7, skopje (in macedonian). arsovski, m. (1997): tectonics of macedonia. faculty of mining and geology, štip, 1–306. (in macedonian). bačeva, k., stafilov, t., šajn, r. & tănăselia, c. (2012): moss biomonitoring of air pollution with heavy metals in the vicinity of a ferronickel smelter plant.– journal of environmental science and health, part a, 47/4, 645–656. balabanova, b., stafilov, t., šajn, r. & bačeva, k., (2011): distribution of chemical elements in attic dust as reflection of lithology and anthropogenic influence in the vicinity of copper mine and flotation.– archives of environmental contamination and toxicology, 61/2, 173–184. balabanova, b., stafilov, t., bačeva k. & šajn, r. (2010): biomonitoring of atmospheric pollution with heavy metals in the copper mine vicinity located near radoviš, republic of macedonia.– journal of environmental science and health, part a, 45, 1504–1518. barandovski, l., frontasyeva, m.v., stafilov, t., šajn r., pavlov, s. & enimiteva, v. (2012): trends of atmospheric deposition of trace elements in macedonia studied by the moss biomonitoring technique.– journal of environmental science and health, part a, 47/13, 2000–2015. battarbee, r., anderson, n., appleby, p., flower, r.j., fritz, s., haworth, e., higgit, s., jones, v., kreiser, a., munro, m.a., natkanski, j., oldfield, f., patrick, s.t., richardson, n., rippey, b. & stevenson, a.c. (1988): lake acidification in the united kingdom. ensis, london. biljanovska, m., gjorčev, s., taneski, j. & efremov, a. (1996): management with soild waste and hazardous waste.– neap, ministry of urban planning, construction and environment, skopje (in macedonian). boev, b. (2006): pelagonia marble valley. preda – agency for development of the enterprises from prilep region, prilep. davis, j.c. (1986): statistic and data analysis in geo logy.– willey in sons, new york, 651 p. dawson, k.m. (1996): skarn zinc-lead-silver. in geology of canadian mineral deposit types. edited by eckstrand, o.r., sinclair, w.d., thorpe, r.i. geological survey of canada, geology of canada no. 8, 448–459. dimovska, b., šajn, r., stafilov, t., bačeva, k. & tanaselia, c. (2014): determination of atmospheric pollution around the thermoelectric power plant using a moss biomonitoring.– air quality, atmosphere & health, 7/4, 541–557. dudka, s. & adriano, c.d. (1997): environmental impacts of metal ore mining and processing: a review.– journal of environmental quality, 26, 590–602. dumurdzanov, n. (1997): lacustrine neogene and pleistocene in macedonia: proceedings of the field meeting held in yugoslavia in 1995– 1996, international geological correlation program project 329, “neogene of the paratethys”: belgrade, special publication, geoinstitute, no. 21, 31–36. dumurdzanov, n., serafimovski, t. & burchfiel, b.c. (2004): evolution of the neogene-pleistocene basins of macedonia.– geological society of america digital map and chart series 1 (accompanying notes), boulder, colorado, 20 p. duruibe, j.o., ogwuegbu, m.o.c. & egwurugwu, j.n., (2007): heavy metal pollution and human biotoxic effects.– international journal of physical sciences, 2/5, 112–118. filipovski, gj. (2003): soils degradation as a component of the environment in the republic of macedonia, macedonian academy of sciences and arts, skopje. gapkovski, n. & jovanovski, m. (2007): general geology.– faculty of civil engineering, skopje. garbarino, j.r., hayes, h., roth, d., antweider, r., brinton, t.i. & taylor, h. (1995): contaminants in the mississippi river, u. s. geological survey circular 1133, virginia, u.s.a. hutton, m & symon, c. (1986): the quantities of cadmium, lead, mercury and arsenic entering the u.k. environment from human activities.– science of the total environment, 57, 129–150. geologia croatica 68/3geologia croatica 272 stafilov, t., šajn, r., boev, b., cvetković, j., muka etov, d. & andreevski, m. (2008b): geochemical atlas of kavadarci and the environs, faculty of natural sciences and mathematics, skopje. stafilov, t., peeva, l., nikov, b. & de koning, a. (2009): industrial hazardous waste in the republic of macedonia. applied environmental geochemistry – anthropogenic i̇mpact on human environment in the se europe, ljubljana, proceedings book (šajn, r., ži̇bert, g. & ali̇jagi̇ć, j., (eds.)), isbn 978-961-6498-18-0, 108-112. stafilov, t., šajn, r., pančevski, z., boev, b., frontasyeva, m.v. & strelkova, l.p. (2010a): heavy me tal contamination of surface soils around a lead and zinc smelter in the republic of macedonia.– journal of hazardous mate ri als, 175, 896–914. stafilov, t., šajn, r., boev, b., cvetković, j., mukaetov, d., andreevski, m. & lepitkova, s. (2010b): distribution of some elements in surface soil over the kavadarci region, republic of macedonia.– environmental earth sciences, 61/7, 1515–1530. stafilov, t. (2014): environmental pollution with heavy metals in the republic of macedonia.– contribution, section of natural, mathematical and biotechnical sciences, masa, 35/2, 81–119. stafilov, t., šajn, r., sulejmani, f. & bačeva, k. (2014). geochemical properties of topsoil around the open coal mine and oslomej thermoelectric power plant, r. macedonia.– geologia croatica, 67/1, 33–44. stojanov, r. (1974): petrological features of magmatic and metamorphic rocks of the wider environment of prilep.– transactions of the geological institute, phd thesis, skopje. stojanović, m. (1989): historical geology, faculty of natural sciences and mathematics, skopje (in macedonian). šajn r. (2003): distribution of chemical elements in attic dust and soil as reflection of lithology and anthropogenic influence in slovenia.– journal de physique, 107, 1173–1176. šajn r. (2005): using attic dust and soil for the separation of anthropogenic and geogenic elemental distributions in an old metallurgic area (celje, slovenia).– geochemistry: exploration, environment, analysis, 5, 59–67. šajn r. (2006): factor analysis of soil and attic-dust to separate mining and metallurgy influence, meza valley, slovenia.– mathematical geology, 38, 735–747. theocharopoulos, s.p., wagner, g., sprengart, j., mohr, m-e., desaules, a., muntau, h., christou, m. & quevauviller, p. (2001): european soil sampling guidelines for soil pollution studies.– the science of the total environment, 264, 51–62. trajkovska, m. & vrencovski, a. (2001): impact of emissions of pollutants from the air by thermal power plants in the republic macedonia on environmental pollution. collection of papers from the meeting “coals in the republic of macedonia”, mining institute, skopje. manuscript received july 23, 2015 revised manuscript accepted september 29, 2015 available online october 31, 2015 jovanovski, g., boev, b. & makreski, p. (2012): minerals from the republic of macedonia with an introduction to mineralogy, macedonian academy of sciences and arts, skopje. kabata-pendias, a. & pendias, h. (2001): trace elements in soil and plants, third ed., crc press, boca raton. lazarevski a. (1993): climate in macedonia, kultura (in macedonian). mihajlov, m., barandovski, l., šajn, r. & stafilov, t. (2013): spatial distribution of heavy metals in soils from the republic of macedonia, 10th congress of pure and applied chemistry for the students of macedonia with international participation, 17-19 october 2013, skopje, book of abstracts, z. noneska, d. stanoeva-gogovska (eds.), p. 24. mihajlov, m. (2014): distribution of heavy metals in soils in republic of macedonia. msc thesis, faculty of natural sciences and mathematics, ss cyril and methodius university, skopje. mitkova, т. & mitrikeski, ј. (2005): soils of the republic of macedonia: present situation and future prospects. european soil bureau, research report no. 9. nriagu, j.o. (1989): a global assessment of natural sources of atmospheric trace metals.– nature, 338, 47–49. peplow, d. (1999): environmental impacts of mining in eastern washington, center for water and watershed studies fact sheet, university of washington, seattle. qin, c., luo, c., chen, y. & shen, z. (2012): spatial-based assessment of metal contamination in agricultural soils near an abandoned copper mine of eastern china.– bulletin of environmental contamination and toxicology, 89/1, 113–118. reimann, c., filzmoser, p. & garrett, r.g. (2002): factor analysis applied to regional geochemical data: problems and possibilities.– applied geochemistry, 17, 185–206. salminen, r., batista, m.j., bidovec, m., demetriades, a., de vivo, b., de vos, w., duris, m., gilucis, a., gregorauskiene, v., halamic, j., heitzmann, p., jordan, g., klaver, g., klein, p., lis, j., locutura, j., marsina, k., mazreku, a., o’connor, p.j., olsson, s.å., ottesen, r.t., petersell, v., plant, j.a., reeder, s., salpeteur, i., sandström, h., siewers, u., steenfelt, a. & tarvainen, t. (2005): geochemical atlas of europe, part 1, background information, methodology and maps, geological survey of finland, espoo, 526 p. snedecor, g.w. & cochran, w.g. (1967): statistical methods, the iowa state university press, ames, iowa, 575 p. stafilov, t., šajn, r., pančevski, z., boev, b., frontasyeva, m.v. & strelkova, l.p. (2008a): geochemical atlas of veles and the environs, faculty of natural sciences and mathematics, skopje. 2021 | 74/2 | 177–187 | 2 figs. | 3 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the advancement of geochemical techniques, in particular the development of advanced mass spectrometry techniques, has allowed us to more accurately determine a number of stable isotope ratios and broaden the set of proxies for many geological and environmental processes. in addition to traditional stable isotopes, such as c, o, and h, the discussion on isotopic signatures of different geological settings has thus extended to new ones, called non-traditional isotopes (e.g., li, mg, ca, cr, mn, fe, cu, zn, se, cl, etc.), which, unlike the traditional ones, cannot be analyzed by gas-source mass spectrometry (teng et al., 2017). although the idea of using an isotope signature in geological studies is not new (nägler et al., 2000; böhm et al., 2006; chan et al., 2006; hippler et al., 2006; fantle & tipper, 2014; etc.), as our knowledge of isotope fractionation in different environmental compartments grows, our ability to use them significantly increases. in this regard, sediments, as archives of environmental changes and conditions, play a crucial role. as major reservoirs of trace metals in the aquatic environment, their total content and isotopic fractionation have the potential to distinguish between the contributions of different phases to the sediment content, e.g. biogenic, authigenic, and lithogenic, as well as to provide information on redox conditions and diagenetic and weathering processes (chan et al., 2006; little et al., 2014; blättler et al., 2015; little et al., 2017; ahm et al., 2018; ciscato et al., 2018; bruggmann et al., 2019; hu et el., 2019). this review summarizes recent findings on the application of non-traditional stable isotopes of: the alkali metal (li), alkaline earth metals (ca, mg, and sr) and the transition metals (ni, cr, and cu) group in the interpretation of post-depositional processes and environmental conditions (i.e. redox conditions and non-traditional stable isotope signatures in geological matrices as a tool for interpreting environmental changes – a review željka fiket*, martina furdek turk, maja ivanić and goran kniewald ruđer bošković institute, division for marine and environmental research, bijenička cesta 54, 10000 zagreb, croatia; (*correspondence: zeljka.fiket@irb.hr) doi: 10.4154/gc.2021.12 abstract the development of new analytical techniques enabled the precise determination of the expanded set of stable isotopes and provided new insight into existing geological issues. this review outlines recent studies of non-traditional isotope signatures in geological matrices, summarizing in one place, new data for the stable isotopes of ca, mg, sr, li, ni, cr, and cu and their application in the interpretation of environmental processes. although some, such as δ44ca and δ26mg, have previously been used to track changes in seawater chemistry throughout geological history, recent studies report their application as geochemical proxies of post-depositional processes. similarly, isotopic signatures of strontium, previously used in radioactive isotope chronology, and δ7li, used in tracing plate subduction and crust/mantle material cycling, found a new application in studies of weathering patterns. the use of δ53cr and δ 65cu isotope signatures, on the other hand, reflects their fractionation under different redox conditions, whereas δ60ni, due to its adsorption and co-precipitation with sulfide species and fe-mn phases, is used in interpreting the contributions of different material sources. and while the isotopic signatures of all these elements indicate certain environmental conditions and processes (e.g. post-depositional processes, redox conditions, organic matter input, the contribution of sources, etc.), by combining them a more comprehensive insight into the investigated environment can be achieved. biological activity), as well as in deciphering the contributions of different sources. while the isotopic signatures of li, sr, ca, and mg in sediments as indicators of subduction and continental crust formation or as age and temperature palaeo-proxies have been widely discussed in the literature (nägler et al., 2000; böhm et al., 2006; chan et al., 2006; hippler et al., 2006; fantle & tipper, 2014; saenger & wang, 2014; teng, 2017; guo et al., 2019), their use in the interpretation of postdepositional processes has only recently been more extensively investigated (fantle & higgins, 2014; chanda & fantle, 2017; teng et al., 2017; bradbury & turchyn, 2018; hu et al., 2019; li et al., 2019). the same applies to the application of isotopic variability of the transition metals as a tool for solving specific problems in palaeoand recent environmental settings (gueguen et al., 2016; baconnais et al., 2018; little et al., 2018; bruggmann et al., 2019). to date, research on the latter is extremely scarce and additional efforts need to be made to produce a more comprehensive database on the isotope variability of these elements in different matrices. although the existing literature provides a valuable overview of the current knowledge on non-traditional isotopes, it most often relates to only one, rarely several, isotopes together (chan et al., 2006; fantle & higgins, 2014; little et al., 2014; blättler et al., 2015; chanda & fantle, 2017; little et al., 2017; baconnais et al., 2018; bradbury & turchyn, 2018; ciscato et al., 2018; bruggmann et al., 2019; hu et el., 2019; li et al., 2019). however, the intertwining of different processes occurring simultaneously in an environment necessitates the use of larger data sets that include more stable isotopes as well as their total element concentrations. the review presented here thus provides an overview of the latest research on the subject, summarizing in one place new data on nonarticle history: manuscript received november 11, 2020 revised manuscript accepted march 29, 2021 available online june 30, 2021 keywords: non-traditional isotopes; ca and mg; sr and li; transition metals; geological matrices g eo lo gi a c ro at ic a 178 geologia croatica 74/2 traditional isotopes (ca, mg, sr, li, ni, cr, and cu) in different geological environments and highlighting the need for a comprehensive database that would allow us to properly argue their use in interpreting environmental changes through earth’s history. the listed elements were selected as those that have found new applications with the development of spectrometry techniques or as representatives of a group of transition metals the isotopic composition of which is nowadays used in the interpretation of numerous processes in palaeoand recent environments. 2. stable isotopes and notation nowadays, stable isotope determinations are generally performed on multi-collector inductively coupled plasma mass spectrometry instruments (mc-icp-ms; e.g. nu instruments, uk or neptune, thermo-fisher, bremen, germany) (e.g. blättler et al., 2015; little et al., 2014; little et al., 2017; ciscato et al., 2018; hu et al., 2019; etc.). detailed guidelines and recommended terms for expressing stable isotope ratios, as well as a description of the assessment of international reference materials for isotope-ratio analysis, can be found elsewhere (coplen, 2011; brand et al., 2014). the following are the elements described in this review paper, their isotopes, and an explanation of associate isotope composition records. magnesium has three stable isotopes, 24mg, 25mg and 26mg, with the relative abundances of 78.99%, 10.00% and 11.01%, respectively, whereas there are six naturally occurring calcium isotopes: 40ca, 42ca, 43ca, 44ca, 46ca and 48ca, with abundances of 96.941%, 0.647%, 0.135%, 2.086%, 0.004% and 0.187%, respectively. magnesium stable isotope data are reported using the standard per mil (‰) notation of δ26mg, i.e., the per mil deviation of the measured 26mg/24mg ratios of the unknowns relative to those of the international δ‐zero reference material dsm3. although the dsm3 reference material is no longer available and has now been replaced by the erm-ae143, calibrated to the dsm3, results are still reported vs. dsm3: δ26mg = [(26mg/24mg)sample / (26mg/24mg)dsm3 – 1] x 1000 (1) for ca, the isotopic composition is expressed in ‰ relative to the international standard reference material nist srm 915a or b, as δ44/40ca or δ44ca. δ44ca = [(44ca/40ca)sample / (44ca/40ca)nist srm 915a/b – 1] x 1000 (2) strontium is an alkali-earth metal with four stable naturally occurring isotopes; 84sr, 86sr, 87sr, and 88sr, whereby 87sr is also partly radiogenic, being produced by beta-decay of the radionuclide 87rb with a half-life of 48.8 x109 years (semenishchev et al., 2020). contrary to the 87sr/86sr ratio that gradually increases over time, the proportion between 84sr, 86sr, and 88sr is constant in nature, but can change in processes where natural fractionation of isotopes occurs (semenishchev et al., 2020). for sr, the stable isotopic composition is expressed in ‰ relative to the international standard reference material srm987 (nist): δ88sr = [(88sr/86srsample) / (88sr/86srsrm987) − 1] x 1000 (3) unlike the δ88sr ratio, expressed in per mil, the relative proportion of radiogenic to stable sr isotopes, i.e. 87sr/86sr isotopic ratio, has commonly been reported in terms of a fourto six-place decimal notation instead of δ-notation. lithium was one of the few elements produced during the big bang nucleosynthesis. it is composed of two stable isotopes 6li and 7li, with the heavier one being far more abundant (92.41%). its isotopic composition is expressed in ‰ relative to the international standard reference material nist l-svec or irmm-016 (li et al., 2010) as δ7li values: δ7li = [(7li/6li)sample / (7li/6li)standard – 1] x 1000 (4) naturally occurring nickel is composed of five stable isotopes: 58ni, 60ni, 61ni, 62ni, and 64ni, with 58ni being the most abundant (68.077% natural abundance), and 26 radioisotopes. its isotopic composition is expressed in ‰ relative to the international standard reference material nist srm 986 as δ60ni values: δ60ni = [(60ni/58ni)sample / (60ni/58ni)srm 986 – 1] x 1000 (5) naturally occurring chromium is composed of four stable isotopes: 50cr, 52cr, 53cr, and 54cr, with 52cr being the most abundant (83.789% natural abundance). its isotopic composition is expressed in ‰ relative to the international standard reference material nist srm 979 as δ53cr values: δ53cr = [(53cr/52cr)sample / (53cr/52cr)srm 979 – 1] x 1000 (6) copper has two stable isotopes, 63cu (69.17%) and 65cu (30.83%), along with 27 radioisotopes. natural mass-dependent variations in 65cu/63cu span 15‰, and are expressed relative to the nist srm 976 standard as δ65cu values: δ65cu = [(65cu/63cu)sample / (65cu/63cu)srm 976 – 1] x 1000 (7) 3. non-traditional isotopes as geochemical proxies of post-depositional processes 3.1. weathering the radiogenic sr isotope ratio (87sr/86sr) has long been known as a reliable tool in geochronological studies as well as in provenance investigation. namely, the radiogenic 87sr/86sr ratio generally varies with age and rb/sr ratios result in the 87sr/86sr ratio being an excellent tracer for the source(s) of sr (andrews et al., 2016; semenishchev et al., 2020) (table 1). however, with recent advances in mass-spectrometry, small variations in stable sr isotope abundances (reported as δ88sr) can be accurately quantified (fietzke & eisenhauer, 2006; ohno & hirata, 2007) and are increasingly used to gain further insight into the sr cycle and its primary controls (andrews et al., 2016). so far, the fractionation of the stable isotopes of sr has been documented in terrestrial, marine, and biological processes; wherein the lighter δ86sr isotopes are preferentially incorporated into biogenic carbonates (+0.14‰ to +0.27‰, krabbenhöf et al., 2010), while inorganic ca-carbonates and seawater are enriched in the heavy sr isotope and therefore display more positive δ88sr values (+0.25‰ to +0.37‰ in carbonates (halicz et al., 2008); 0.310(8)‰ as an average value for seawater (krabbenhöf et al., 2010); 0.407 ± 0.012‰ in seawater from the pacific and atlantic oceans (wakaki et al., 2017); or 0.35 ± 0.06‰ for g eologia c roatica 179fiket et al.: non-traditional stable isotope signatures in geological matrices as a tool for interpreting environmental changes – a review the mediterranean sea (halicz et al., 2008; table 1), analogous to ca isotopes. still, the sr isotopic fractionation in terrestrial and marine systems is relatively small, with δ88sr values varying by ∼2.5‰ (fietzke & eisenhauer, 2006; ohno & hirata, 2007; krabbenhöf et al., 2010; andrews et al., 2016; wakaki et al., 2017; semenishchev et al., 2020). compared to other elements and isotopes, sr is unique in that its isotopic records contain information on both the source of sr (87sr/86sr) and the mass-fractionating processes that it has witnessed (δ88sr). the combined application of these data can thus lead to a more comprehensive understanding of the weathering cycle of sr. the latter was also suggested by míková (2012) in table 1. strontium and lithium isotope composition in different types of samples. isotope δ sample type reference δ88sr +0.310(8)‰ seawater, average krabbenhöf et al., 2010 +0.407‰ ± 0.012‰ pacific and atlantic seawater wakaki et al., 2017 +0.39‰ ± 0.02‰ deep pacific seawater scher et al., 2013 +0.14‰ to +0.27‰ marine biogenic carbonates krabbenhöf et al., 2010 +0.27‰ to +0.37‰ marine inorganic carbonates halicz et al., 2008 +0.35‰ ± 0.06‰ mediterranean sea halicz et al., 2008 −0.17‰ ± 0.06‰ terra rossa soil and speleothem calcite halicz et al., 2008 +0.26‰ ± 0.1‰ aragonite halicz et al., 2008 +0.22‰ ± 0.07‰ corals halicz et al., 2008 +0.35‰ ± 0.06‰ seawater halicz et al., 2008 -0.14‰ to -0.20‰ terrestrial carbonates halicz et al., 2008 +0.253‰ to 0.361‰ hydrothermal fluids krabbenhöf et al., 2010 +0.28‰ ± 0.09‰ gneiss de souza et al., 2010 +0.15‰ to +0.31‰ granite de souza et al., 2010 +0.29‰ to +0.31‰ soil de souza et al., 2010 +0.24‰ to +0.42‰ rivers krabbenhöf et al., 2010 +0.27‰ to +0.33‰ river sediments andrews et al., 2016 ~0.267‰ carbonate fraction of soils and sediments andrews et al., 2016 ~0.263‰ silicate fraction of soils and sediments andrews et al., 2016 +0.223‰ to +0.369‰ soil exchangeable fraction andrews et al., 2016 -0.11‰ to +0.42‰ plants oeser & blanckenburg, 2020 δ7li +31‰ ocean seawater penniston-dorland et al., 2017 +1‰ to +44‰ river water penniston-dorland et al., 2017 +17‰ to +35‰ lake water penniston-dorland et al., 2017 +6‰ to +29‰ groundwater penniston-dorland et al., 2017 +5‰ to +11‰ hydrothermal fluids penniston-dorland et al., 2017 -3‰ to +26‰ geothermal waters penniston-dorland et al., 2017 31‰ seawater chan et al., 2006 -2‰ to 5‰ clays chan et al., 2006 -4.3‰ to +14.5‰ marine sediments chan et al., 2006 -1.5‰ to +5% clay rich detrital sediments chan et al., 2006 +0.5‰ to +3.6‰ laki basalts (hawaii) pistiner & henderson, 2003 +2.2‰ to +4.7‰ hawaii soil pistiner & henderson, 2003 +9.8‰ rainwater (unfiltered) pistiner & henderson, 2003 +18.1‰ rainwater (filtered) pistiner & henderson, 2003 +2.4‰ to +4.6‰ basalt pistiner & henderson, 2003 +8.8‰ to +9.1‰ granite pistiner & henderson, 2003 +3.1‰ to +12.0‰ sao miguel rivers bedload pogge von strandmann et al., 2010 +3.5‰ to +9.5‰ sao miguel rivers suspended load pogge von strandmann et al., 2010 +18.2‰ to +36.2‰ sao miguel rivers dissolved load pogge von strandmann et al., 2010 +5.9‰ to +9.8‰ sao miguel rivers dissolved load in rivers influenced by hydrothermal input pogge von strandmann et al., 2010 +6.9‰ sao miguel hot spring pogge von strandmann et al., 2010 +32.8‰ sao miguel rivers rainwater pogge von strandmann et al., 2010 +2.8‰ to +8.9‰ iceland rivers bedload pogge von strandmann et al., 2006 −1.3‰ to 7.5‰ iceland rivers suspended load pogge von strandmann et al., 2006 +17.0‰ to +43.7‰ iceland rivers dissolved load pogge von strandmann et al., 2006 +10.9‰ iceland hot spring pogge von strandmann et al., 2006 +22.8‰ hraunfossar, iceland groundwater pogge von strandmann et al., 2006 +33.3‰ ice (iceland) pogge von strandmann et al., 2006 + 0.6‰ ± 0.6‰ continental crust sauzéat et al., 2015 0‰ ± 2‰ continental crust teng et al., 2004 +6‰ to +32‰ carbonates pogge von strandmann et al., 2019 6.1‰ ± 1.3‰ seawater calcite pogge von strandmann et al., 2019 9.6‰ ± 0.6‰ seawater aragonite pogge von strandmann et al., 2019 g eo lo gi a c ro at ic a 180 geologia croatica 74/2 her review on tracing weathering processes and flow pathways in surface and ground waters in antarctica and terrains with a retreating glacier using strontium isotopic composition. a similar approach was also adopted by andrews et al. (2016) using radiogenic sr isotope ratios (87sr/86sr), stable sr isotope ratios (δ88sr), and major ion data to identify river cation sources and their biogeochemical cycling within the cleddau and hollyford river catchments in the milford sound region of fiordland, new zealand. their results suggested that the soil water δ88sr values are ∼0.30‰ higher than the bedrock δ88sr values, while mixing calculations showed that the plant-fractionated soil water pool contributes ∼27% of the riverine sr. also, by combining the δ88sr values and ca/sr and 87sr/86sr ratios, three major contributions to the sr riverine budget in the milford sound region were identified; i) silicate (with δ88sr amounting to ~0.263 ‰); ii) carbona te weathering (with δ88sr amounting to ~0.264‰); iii) soil water input (with δ88sr between 0.223‰ and 0.369‰). similarly, continental waters were found to be enriched with 88sr compared to the rocks in their drainage basins (e.g. krabbenhöf et al., 2010; moynier et al., 2010). to explain this phenomenon, shalev et al. (2017) suggested that during precipitation of continental carbonates (i.e. carbonates precipitated from the surface, pedogenic, or groundwater) a fractionation of strontium isotopes occurs that contributes to the enrichment of 88sr in rivers. however, this would also require that a surprisingly large proportion (∼40%) of the originally weathered sr to co-precipitate with continental carbonates, suggesting that some other mechanisms, such as sr uptake in plants and/or incongruent weathering of silicates, play a significant role in the sr cycle (shalev et al., 2017). oeser & blackenburg (2020) concluded that the release of sr during weathering is isotopically congruent and that, despite a strong biological fractionation (-0.40‰ to +0.34‰), the plant production – degradation cycle is isotopically neutral. the potential fractionation in the bioavailable sr pool was explained by the loss of sr from the system by organic solids enriched in the light 86sr isotope. the understanding of stable sr isotope fractionation during weathering is however, still very limited (halicz et al., 2008; de souza et al., 2010; shalev et al., 2017) (table 1), and necessitates further investigation. in addition to sr, li isotopes have also been reported as contributing to a better understanding of weathering processes ( fig. 1). namely, the significant fractionation of li isotopes occurs during silicate weathering, from over 26‰ and up to 35‰ in river and surface environments (pistiner & henderson, 2003), with the preferential incorporation of 6li in neo-formed clay minerals (e.g. pistiner & henderson, 2003; pogge von strandmann et al., 2010; sauzéat et al., 2015), and the mobilization of heavier 7li into solution. on continents, the δ7li value is thus controlled by the leaching rates of silicate source rocks and the amounts of neo-formed clays. consequently, areas with weathering-limited regimes (e.g. mountainous or glaciated regions), as well as those with transport-limited regimes (e.g. areas with thick soil sequences), are usually characterized by high δ7li signatures, except when underlain by shales. in rivers, the δ7li isotopic signature is driven by the lithology of the drainage area, where the primary lithology determines the secondary mineralogy (e.g. pogge von strandmann et al., 2006; 2010; sauzéat et al., 2015), the corresponding weathering intensity, the concentration of river suspended load (pogge von strandmann et al., 2006;), as well as the subsurface residence time of infiltrating meteoric waters (pistiner & henderson, 2003; sauzéat et al., 2015) (table 1). all the latter conditions show significantly greater variability of δ7li in rivers. for example, in river waters the δ7li is +1‰ to +44‰ (penniston-dorland et al., 2017), -1.3‰ to +9.5‰ in the suspended load (pogge von strandmann et al., 2006; 2010), and 17.0‰ to 43.7‰ in the dissolved load (pogge von strandmann et al., 2006; 2010), while in silicate rocks the values are ~0‰ in the continental crust (teng et al., 2004; sauzéat et al., 2015) and ~3–5‰ in basalts (pistiner & henderson, 2003; sauzéat et al., 2015). marine sediments are, on the other hand, enriched in heavier 7li, with δ7li values ranging from 4.3‰ to +14.5‰ (chan et al., 2006), while carbonates display an even broader range and generally correspond to δ7li values between +6‰ and +32‰ (pogge von strandmann et figure 1. schematic representation of the distribution of δ88sr and δ7li in different environmental compartments. g eologia c roatica 181fiket et al.: non-traditional stable isotope signatures in geological matrices as a tool for interpreting environmental changes – a review al., 2019). in the ocean, lithium acts as a conservative element with a residence time of about one million years and a δ7li isotopic signature of +31‰ (penniston-dorland et al., 2017). the steady-state is maintained by river inputs during continental weathering (+23‰), inputs by groundwater (+15‰) and hydrothermal fluids (+7‰), and the preferential removal of 6li from seawater by clay minerals (penniston-dorland et al., 2017; and references therein); the combination of which also explains the heavier δ7li signature compared to its inputs. the prevalent incorporation of li into silicate minerals compared to other mineral phases results in the li isotopic signature being a promising proxy for evaluating changes related to the continental silicate weathering patterns (pistiner & henderson, 2003; chan et al., 2006). in contrast to radiogenic isotopic ratios used to monitor chemical weathering, such as 87sr/86sr, the li isotopic composition of river water is not highly sensitive to those of the bedrock, as it mainly reflects the weathering intensity and formation of clay minerals. thus, by combining the li and sr isotopic signatures of different geological environments (fig. 1) with mineralogical data, a more complete insight into the weathering processes as well as into the cycling of these elements in the environment can be achieved. 3.2. diagenesis after deposition, sediments are subjected to diagenetic alteration, which can affect their geochemical fingerprint. the extent to which the primary sediment was altered can provide crucial information needed for the reconstruction of environmental conditions under which it was deposited (blättler et al., 2015; chanda & fantle, 2017; higgins et al., 2018). to successfully tackle this topic, the following authors used a multi-parameter concept. fantle & higgins (2014) combined the traditional approach, using elemental ratios and stable isotopes of c and o, with the non-traditional, i.e. isotopic composition of ca and mg, to assess the extent of diagenetic alteration of geochemical proxies in shallow marine carbonates from odp (ocean drilling program) site 1196a. the results of their study suggest that the variability in δ44ca (from 0.60‰ to 1.131‰) and δ26mg (from -3.91‰ to -2.59‰) values, along with the variations in other geochemical proxies (c and o isotopes), can be used to elucidate diagenetic alterations, namely limestone diagenesis, and dolomitization. these authors also highlighted the importance of using several parameters when deciphering diagenetic changes in the sedimentary record. a similar multi-proxy approach has been implemented by higgins et al. (2018) in their study of early-marine diagenetic alterations and their effect on the geochemical proxies of shallowwater carbonate sediments. the authors combined measurements of the isotopic composition of ca and mg with other geochemical proxies (δ13c, δ18o, sr/ca, mg/ca) and the mineralogical composition in sediments and pore fluids at ten sites in the bahamas and the eucla shelf. their study showed that variations in the isotopic composition of ca (-1.56‰ to -0.35‰) and mg (-3.46‰ to -2.19‰) in the stratigraphic record were influenced by changes in the carbonate mineralogy and the type of diagenetic alteration, fluidbuffered vs. sediment-buffered diagenesis (table 2). in the majori ty of the bahamian sediments, fluid-buffered diagenetic processes combined with the transformation of aragonite and high-mg calcite to low-mg calcite and dolomite resulted in the coherent stratigraphic variability of δ44ca values and carbonatespecific geochemical proxies, such as δ13c, δ18o, and sr/ca as well as in the trace element records. based on previous findings (blättler et al., 2015; chanda & fantle, 2017), ahm et al. (2018) presented a numerical model that estimated the extent and type (fluidvs. sediment-buffered) of early-diagenetic processes in carbonate sediments and their influence on other carbonate-specific geochemical proxies. through tracking the elemental and isotopic composition of carbonate-bound geochemical proxies (ca, mg, c, o, sr/ca), the model proposed by these authors was able to estimate the extent of diagenetic alteration, describe the diagenetic fluid and provide more insight into the variation of geochemical proxies in ancient carbonate deposits. recently, li et al. (2019) combined the δ26mg isotopic signature of dolomite (ranging from -2.28‰ to -1.78‰), with trace element analysis, the isotopic composition of c, and o, and mineralogical analysis to determine the dolomite formation depth in massive cretaceous dolostones. the authors highlighted the importance of the dolomitization depth and mechanism on the mg-c isotope response in the sedimentary record. studies of modern dolomitization processes (fantle & higgins, 2014; blättler et al., 2015; chanda & fantle, 2017) show that during early diagenesis δ26mg values in dolomites are controlled by porewater chemistry. thereby, the evolutionary patterns of porewater chemistry differ in different types of early diagenetic systems due to changes in the hydrological conditions and result in stratigraphic variations in the composition of the mg isotope in carbonates (ahm et al., 2018; higgins et al., 2018). on the other hand, mesozoic-palaeozoic dolostones formed by massive dolomitization have been reported as potential archives of coeval seawater mg isotope signals (hu et al., 2019). hu et al. (2019) studied the relationships between post-depositional processes and mg isotope variabilities in massive dolomites by complementing magnesium isotope analyses with the analysis of c-o isotopic composition, rare earth element (ree) concentrations and the petrographic features of dolo stones. their results indicated that different types of syndiagenetic dolomites deposited in different sedimentary settings have uniform δ26mg values of -2.06‰ ± 0.20‰, implying that the chemistry of the porewater was buffered by coeval seawater during dolomitization, irrespective of sedimentary settings. furthermore, their results suggested that post-depositional processes, including diagenetic and hydrothermal alterations, did not induce notable changes in the mg isotope signals in the dolomite. 3.3. authigenic mineral formation authigenic formation of clay minerals is another sedimentary component that significantly affects the isotope fractionation in the pore fluids. bradbury & turchyn (2018) used calcium isotopes to evaluate the influence of sediment type on carbonate precipitation, dissolution, and recrystallization. the analysis was performed on sediments from odp sites 1081 and 1086, off the coast of west africa, two geographically close sites with a different share of carbonates and organic matter. the authors combined ca isotope composition of sediments (δ44ca = –0.42‰ – –0.21‰, reported relative to bulk silicate earth) with sr and ca concentrations in pore fluids (δ44ca = –0.08 – +1.04‰) to model the rates of carbonate dissolution and precipitation. their results suggested the occurrence of ca isotope fractionation during precipitation of carbonate. g eo lo gi a c ro at ic a 182 geologia croatica 74/2 blättler et al. (2015) on the other hand, used mg and ca isotopes as geochemical tracers for authigenic carbonate formation in marine sediments of miocene age. similarly to fantle & higgins (2014), the authors combined measurements of δ26mg and δ44ca (delta values of ca are reported relative to modern seawater), with those of δ13c and δ18o, performing a multiisotope study on authigenic dolomites occurring as beds and nodules within the stratigraphic sequence of the monterey formation, offshore california. their data suggested that the obtained isotopic signature of mg and ca point to dolomite precipitation and carbonate recrystallization, respectively. there, the variability of δ26mg (from -2.86‰ to -0.52‰) and δ44ca values (from -1.10‰ to -0.35‰) with stratigraphic depth, and anti-correlation of mg and ca isotopes, was related to early-diagenetic processes in the sedimentary pore fluid. the large variation of δ13c values in dolomite on the other hand, was attributed to its formation in zones of bacterial sulfate reduction or methanogenesis. kimmig & holmden (2017) investigated the potential of mg isotopes, combined with other geochemical proxies (sr/ca and ca/mg ratios, δ 13c, mineralogy) to identify changes in carbonate polymorph mineralogy in a carbonate mud deposit marked by the hirnatian glaciation. their results showed that in the investigated section, during the glaciation event, a 2–3‰ increase in sedimentary δ26mg values occurred. the changes in the abundance of dolomite in the host limestone were considered responsible for the observed shifts in δ26mg, which was also in agreement with other geochemical proxies and indicators of sea-level changes. according to the trends observed for the δ26mg and ca/mg ratios, changes in carbonate mineralogy (e.g. variations in the abundance of aragonite) induced the following changes in the δ26mg isotopic composition of limestone: -4.45 ± 0.82‰ before glaciation, -2.54 ± 0.23‰ during glaciation and -3.05 ± 0.27‰ after glaciation. this exemplifies the potential of a multi-proxy approach in the identification of changes in carbonate polymorphs in sedimentary records. 3.4. adsorption-desorption processes while carbonates preferentially incorporate light mg and ca isotopes (fantle & higgins, 2014; blättler et al., 2015; kimmig & holmden, 2017; higgins et al., 2018), limestone diagenesis and dolomitization cause their shift towards lower or higher values, respectively (table 2). in contrast to carbonates, clay minerals display heavier δ26mg values (-1.82‰ to +0.18‰; wimpenny et al., 2014), but also to some extent variable ones, depending on the share of the exchangeable and the structurally incorporated mg. similar to magnesium, the calcium isotope composition of pore waters was also found to be influenced by the adsorption/desorption processes of ca2+ from the surfaces of clay minerals (ockert et al., 2013). ockert et al. (2013) investigated the influence of cation exchange between different clay minerals (montmorillonite, illite, and kaolinite) and marine sediment, with ca in artificial seawater. the authors found that in the marine porewater environment the light ca preferentially adsorbs onto clay minerals with the fractionation between the adsorbed and the dissolved ca2+ and δ44ca varying between +0.09‰ and -2.76‰. their results also suggested a mineral specific fractionation of ca, where kaolinite (-1.2‰ and -2.76‰ during adsorption and desorption, respectively) and illite (-0.82‰ and -1.2‰ during adsorption and desorption, respectively), showed more significant fractionation compared to montmorillonite. also, the presence of ammonium, originating from organic matter decomposition, was considered to cause desorption of ca2+ from the clay mineral surfaces into the pore water. this topic was further studied by brazier et al. (2019) who experimentally showed that the intensity of ca isotopic fractionation during adsorption onto clay minerals is controlled by their structural characteristics, including layer charge, specific surface area, and interlayer space. the results obtained by these authors highlighted the importance of adsorption-desorption processes involving mineral particles in the assessment of ca isotopic signatures in natural environments. the more so as, in addition to carbonates, silicate minerals are the second dominant source of ca and mg in rivers, and therefore seawater, and discerning the key controls of ca and mg isotopic composition during the alteration of primary silicates and formation of alteration phases such as clay minerals can help in understanding how these elements behave during weathering. 4. non-traditional isotopes as indicators of environmental conditions 4.1. redox conditions the chromium isotope system functions as an atmospheric redox proxy because oxidative weathering of crustal cr(iii)-bearing minerals results in the release of 53cr-enriched mobile cr(vi) to the solution (gilleaudeau et al., 2016). cr(vi) is then carried to the oceans via rivers, thus imparting a positively fractionated δ53cr signal to modern seawater (~0.5 ± 0.1‰) (bonnand et al., 2013) compared to crustal values (–0.123 ± 0.102 ‰) (schoenberg et al., 2008). in marine environments, chromium has a tendency to co-precipitate with different mineral phases and readily accumulates in sediments in reducing conditions (e.g. gilleaudeau et al., 2016; fig. 2), which makes δ53cr a valuable redox proxy not only in palaeo-environmental studi es but also in recent marine settings (bonnand et al., 2013; scheiderich et al., 2015; gilleaudeau et al., 2016). according to scheiderich et al. (2015), modern surface seawater is heterogeneous in δ53cr, with isotopic heterogeneity confined to the surface water (from 0.41‰ to 1.51‰ in the atlantic ocean, and from 0.91‰ to 1.43‰ in the pacific ocean; scheiderich et al., 2015), while the deep-water masses in the atlantic and pacific displayed similar δ53cr values (~0.5‰, scheiderich et al., 2015); table 3). in contrast, the study of bruggmann et al. (2019) on chromium isotope cycling in the water column and sediments of the peruvian continental margin, a modern oxygen minimum zone (omz) in an open marine setting, yielded somewhat different values. their results show δ53cr ranging from 0.02 ± 0.16‰ to 0.59 ± 0.11‰ and from 0.31 ± 0.07‰ to 0.92 ± 0.12‰ in seawater and sediments, respectively. the sediments deposited in permanently anoxic waters showed δ53cr at 0.77 ± 0.19‰, while those deposited in oxic bottom waters were characterized by δ53cr at 0.46 ± 0.19‰, suggesting that sediment cr concentrations and δ53cr values are influenced by water column redox (e.g. reductive dissolution and transport of fe-oxides) and/or early diagenetic processes (e.g. redistribution of cr during phosphogenesis). although both mentioned studies emphasize the importance of redox conditions for cr fractionation in marine environments, little is known about redox cycling of cr within the water column, changes across the sediment water interface, and the exact mechanisms by which cr is incorporated into marine sediments, which remain poorly constrained ( scheiderich et al., 2015; bruggmann et al., 2019). all of this is important as most of the studies conducted have neglected the internal fractionation processes in the marine cr cycle, such g eologia c roatica 183fiket et al.: non-traditional stable isotope signatures in geological matrices as a tool for interpreting environmental changes – a review as the export of lighter cr(iii) with organic matter into the sediment (semeniuk et al., 2016). the isotopic composition of ni can also be used (fig. 2) in elucidating the redox processes in sediments. namely, its co-precipitation with fe–mn oxides represents an important output from the dissolved pool in an oxygenated environment (e.g., gall et al., 2013; cameron & vance, 2014; teng et al., 2017; table 3). in reducing conditions, however, ni shows a prefefigure 2. schematic representation of the distribution of δ53cr, δ60ni and δ65cu in different environmental compartments. table 2. magnesium and calcium isotope composition in different types of samples. isotope δ sample type reference δ26mg -2.86‰ to -0.52‰ bulk dolomite blättler et al., 2015 –2.54‰ ± 0.23‰ calcite kimmig & holmden, 2017 +0.18‰ illite wimpenny et al., 2014 -0.30‰ montmorillonite wimpenny et al., 2014 -1.82‰ kaolinite wimpenny et al., 2014 -3.46‰ to -2.19‰ great bahama bank higgins et al., 2018 -3.02‰ to -2.64‰ little bahama bank higgins et al., 2018 -3.13‰ to -3.07‰ bank-top sediment higgins et al., 2018 -3.26‰ to -2.62‰ eucla shelf higgins et al., 2018 -0.72‰ to -0.39‰ pore water chanda & fantle, 2017 -5.00‰ to -2.23‰ bulk carbonates chanda & fantle, 2017 -3.91‰ to -2.59‰ bulk carbonate fantle & higgins, 2014 -3.60‰ ± 0.25‰ limestone, average fantle & higgins, 2014 -2.68‰ ± 0.07‰ dolostone, average fantle & higgins, 2014 -2.28‰ to -1.78‰ dolostone li et al., 2019 -2.29‰ ± 0.10‰ dolostone galy et al., 2002 -2.06‰ ± 0.20‰ syndiagenetic dolomite hu et al., 2019 -0.22‰ ± 0.10‰ ucc li et al., 2010 -0.63‰ to 0.64‰ iceland rivers pogge von strandmann et al., 2008 0.85‰ hydrothermal springs pogge von strandmann et al., 2008 -0.83‰ ice pogge von strandmann et al., 2008 δ44ca -1.10‰ to -0.35‰ bulk dolomite blättler et al., 2015 -1.56‰ to -0.40‰ great bahama bank higgins et al., 2018 -0.68‰ to -0.35‰ little bahama bank higgins et al., 2018 -1.49‰ to -1.20‰ bank-top sediment higgins et al., 2018 -1.24‰ to -0.88‰ eucla shelf higgins et al., 2018 0.60‰ to 1.131‰ bulk carbonate fantle & higgins, 2014 0.97‰ ± 0.24‰ limestone, average fantle & higgins, 2014 1.03‰ ± 0.15‰ dolostone, average fantle & higgins, 2014 -0.08‰ to 1.04‰ pore fluid site 1081 bradbury & turchyn, 2018 -0.42‰ to -0.21‰ sediment site 1081 bradbury & turchyn, 2018 0.11‰ to 0.78‰ pore fluid site 1086 bradbury & turchyn, 2018 -0.42‰ to -0.25‰ sediment site 1086 bradbury & turchyn, 2018 g eo lo gi a c ro at ic a 184 geologia croatica 74/2 rence towards dissolved sulfide (e.g., ciscato et al., 2018) and is either scavenged by reactive sulfide species or sulfide precipitation. while the fe-mn oxides show preference to isotopically heavier isotopes (+0.9‰ to +2.5‰, gall et al., 2013), sulfide phases prefer the isotopically lighter ni (+1.3 ± 0.4‰, ciscato et al., 2018). 4.2. organic matter in addition to co-precipitation with fe-mn-oxyhydroxides or sulfide phases, depending on the redox state, two other important processes control the marine geochemistry of ni and its isotope fractionation; biological cycling via cell uptake and the burial of organics (cameron et al., 2009; cameron & vance, 2014). however, sedimentary outputs that control the heavy δ60ni content of the ocean are at odds with the lighter ni stable isotope composition of the inputs, by 1.3‰ to 1.7‰ (ciscato et al., 2018), a feature common to many other transition metals (e.g. little et al., 2014) (fig. 2). to find a possible explanation for this imbalance, ciscato et al. (2018) investigated upwelling margin sediments and found that the organic-rich sediments beneath upwelling zones are also an important output flux of ni from the oceans. however, they found that the δ60ni in sediments (+0.94‰ to +1.33‰) was almost identical to the δ60ni of modern seawater (+1.19‰ to +1.47‰) (cameron & vance, 2014). despite this similarity, the approach they adopted, by analyzing the ni isotopic signature of both fractions, the organic-sulfides (with δ60ni from +0.86‰ to +1.83‰) and the hf-digestible fraction (with δ60ni from +0.86‰ and +1.37‰), has the potential to quantify isotope fractionations associated with biological uptake as well as to record the δ60ni of the contemporary seawater. even though cr is not considered bio-essential, organic matter can also significantly influence the cr cycle (e.g. semeniuk table 3. chromium, nickel and copper isotope composition in different types of samples. isotope δ sample type reference δ53cr −0.26‰ to −0.04‰ continental crust schoenberg et al., 2008 ~0.5 ± 0.1‰ modern seawater bonnand et al., 2013 +0.412‰ to +0.664‰ argentine seawater bonnand et al., 2013 +0.65‰ to +0.76‰ bahamian and yucatan ooid bonnand et al., 2013 +0.41‰ to +1.51‰ atlantic ocean water scheiderich et al., 2015 +0.61‰ to +1.43‰ pacific ocean water scheiderich et al., 2015 +0.99‰ to +1.55‰ arctic seawater scheiderich et al., 2015 +0.02‰ to +0.59‰ seawater bruggmann et al., 2019 +0.31‰ to +0.92‰ recent sediments bruggmann et al., 2019 0.46 ± 0.19‰ sediments deposited in oxic conditions bruggmann et al., 2019 0.77 ± 0.19‰ sediments deposited in anoxic conditions bruggmann et al., 2019 δ60ni +0.9‰ to +2.5‰ fe–mn crusts gall et al., 2013 +1.79‰ ± 0.21‰ north pacific fe-mn crust li et al., 2019 +1.73‰ ± 0.21‰ south pacific fe-mn crust li et al., 2019 +1.3‰ ± 0.7 ‰ atlantic ocean fe-mn crust gall et al., 2013 +1.7‰ ± 0.8‰ pacific ocean fe-mn crust gall et al., 2013 +1.6‰ ± 0.3‰ indian ocean fe-mn crust gall et al., 2013 +0.94‰ to +1.33‰ sediment ciscato et al., 2018 +0.86‰ to +1.83‰ organic matter and associated pyrite fraction ciscato et al., 2018 +0.86‰ and +1.37‰ hf-dissolvable sediment fraction ciscato et al., 2018 +1.3 ± 0.4‰ sulfide phases ciscato et al., 2018 +0.15‰ ± 0.24‰ terrestrial samples (mantle and crust) cameron et al., 2009 + 1.19‰ to 1.47‰ deep ocean water cameron and vance, 2014 +1.44‰ ± 0.15‰ seawater cameron and vance, 2014 +0.29‰ to +1.34‰ river water cameron and vance, 2014 +0.14‰ ± 0.23‰ river sediments cameron and vance, 2014 δ65cu +0.66‰ ± 0.07‰ south atlantic deep water little et al., 2018 +0.65‰ ± 0.07‰ north atlantic deep water boyle et al., 2012 +0.65‰ ± 0.08‰ indian and pacific ocean deep water takano et al., 2014 +0.70‰ ± 0.11‰ tasman sea deep water thompson et al., 2014 +0.51‰ ± 0.20‰ mediterranean sea baconnais et al., 2018 +0.08‰ ± 0.17‰ lithogenic fraction moynier et al., 2017 +0.31‰ ± 0.11‰ bioauthigenic fraction little et al., 2017 +0.44‰ ± 0.23‰ fe-mn crusts and nodules little et al., 2014 +0.68‰ river water little et al., 2018 +0.11‰ ± 0.09‰ lithogenic part of particulate phase little et al., 2018 +0.40‰ ± 0.10‰ labile fraction of particulate phase little et al., 2018 +0.10‰ to +0.35‰ marine particles maréchal et al., 1999 +0.03‰ to +0.52‰ marine particles thompson et al., 2014 +0.08‰ ± 0.17‰ lithogenic fraction, average moynier et al., 2017 g eologia c roatica 185fiket et al.: non-traditional stable isotope signatures in geological matrices as a tool for interpreting environmental changes – a review et al., 2016) and cr(iii) can be removed from seawater by phytoplankton via adsorption or incorporation, both of which may cause isotope fractionations induced by the initial reduction of cr(vi) to cr(iii) (semeniuk et al., 2016). the stable isotopic signature of copper also has the potential to provide significant information on the biogeochemical cycling of this element in the environment (moynier et al., 2017). similar to chromium, redox transformations between cu(i) and cu(ii) species are the main processes in natural systems resulting in cu isotope fractionation (little et al., 2014; 2017), e.g., reduced and precipitated cu(i) species are known to be lighter by 2‰ to 5‰ relative to dissolved cu(ii) species (ryan et al., 2014). the fractionation between organically complexed and free inorganic species, ranging from +0.1‰ and +0.8‰ (ryan et al., 2014), suggests that complexation by soluble ligands in natural waters further induces significant isotope fractionation of cu. in seawater, 99.9% of dissolved cu is organically complexed, whereby complexation of cu with om favours retention of the heavy isotope in solution (vance et al., 2008). the organic matter (om) is thus considered to be a key variable controlling cu speciation in both terrestrial and aquatic environments. 5. non-traditional isotopes as a tool for deciphering multiple sources contribution by combining data on partitioning and the isotopic fractionation of transition metals between different phases in both terrestrial and aquatic systems, (e.g. between oxides, sulfides or organic matter, or dissolved vs. particulate; table 3; fig. 2), the contribution of the different sources can be differentiated. little et al. (2018) studied cu isotope distributions in the dissolved and particulate phase in the south atlantic. their observations point to the existence of two pools of cu isotopes in the particulate phase, a refractory pool with a lithogenic δ65cu signature (at about 0‰) and a labile pool, associated with organic matter, at about +0.4‰ (table 3). according to their data, the labile pool is isotopically lighter compared to the homogeneous deep ocean dissolved pool at about +0.7‰ (vance et al., 2008; ryan et al., 2014). although the ocean interior is considered to have a very homogeneous cu isotope composition at about +0.65‰ (+0.66 ± 0.07‰ at depths >200 m in the south atlantic; little et al., 2018); +0.65 ± 0.07‰, >200 m in the north atlantic (boyle et al., 2012); +0.65 ± 0.08‰, >200 m in the indian and pacific oceans (takano et al., 2014); +0.70 ± 0.11‰, >200 m in the tasman sea (thompson et al., 2014); and +0.51‰ ± 0.20‰, in the mediterranean sea (baconnais et al., 2018), deviations towards lower δ65cu values have been reported for the upper water column (between +0.41‰ and 0.49‰), and towards higher δ65cu values in the deeper parts of the water column (between +0.75‰ and 0.84‰) (moynier et al., 2017) and reference therein). this variation in isotopic composition along the depth profiles can be attributed to biological activity, aerosol depo sition, and local supply (little et al., 2018). despite this variability, the cu isotope composition of seawater is similar to the riverine input value of +0.68‰ and to the calculated combined riverine and atmospheric cu source of +0.63‰, which is substantially higher compared to the upper continental crust (ucc) at +0.08 ± 0.17‰ (moynier et al., 2017). similar to ni, only two major sinks have been identified so far for cu, fe-mn crusts and nodules and organic-rich sediments, and both of them display a preference for lighter cu isotopes, at +0.44‰ (little et al., 2014) and +0.28‰ (little et al., 2017), respectively. the discrepancy between the light isotope signature of sinks and the heavy isotope signature of the major inputs by rivers requires identification of the additional light source(s) or heavy sink(s). the role of ferromanganese crusts as archives for deep-water ni isotope compositions was studied by gueguen et al. (2016) and gall et al. (2013). gueguen et al. (2016) showed that despite different growth rates, textures and geochemical patterns, fe-mn crusts from both the north and south pacific oceans have had homogenous ni isotope compositions over the last ∼17 ma, yielding average δ60ni values of 1.79 ± 0.21 ‰ and 1.73 ±0.21 ‰, respectively. results of gall et al. (2013) suggested that the heavy ni isotopic signature of crusts (+0.9‰ to +2.5‰) reflects the input to the ocean from continental weathering and possibly also from hydrothermal fluids. despite significant variation in the ni isotopic composition of surface scrapings of fe-mn crusts, they observed low δ60ni variability in different layers of crust from the central pacific ocean that started growing over 70 ma, suggesting that oceanic sources and sinks largely remained in steady-state over the cenozoic. still, the δ60ni values reported by gall et al. (2013) are both heavier and lighter than the modern seawater value determined by cameron & vance (2014), at 1.44 ± 0.15‰. moreover, nickel isotope depth profile s in water columns of the pacific, atlantic, and southern oceans studied by cameron & vance (2014) showed no variations, suggesting that ni isotopes are homogenous in deep waters. at steady-state, the ni isotope composition of seawater is thus controlled by the relative fluxes of ni inputs to the ocean (e.g. rivers, atmospheric deposits, hydrothermal sources) and ni uptake (e.g. authigenic sinks, organic matter burial) (gueguen et al., 2016). since the riverine flux and the scavenging of ni by fe-mn oxides are, respectively, the main input and output fluxes for this element in the ocean (gall et al., 2013; cameron & vance, 2014), gueguen et al. (2016) proposed that the modern marine ni isotope mass balance is controlled by the isotopic composition of these fluxes. although the mechanisms that control the cu and ni isotope fractionation in seawater are still not well understood, their δ65cu and δ60ni isotopic signatures have the potential to distinguish the contribution of different phases to the sediments and when combined with seawater records could provide some new insights into their cycling in both modern and ancient environments. however, to further understand these processes it is necessary to gather a larger dataset of δ65cu and δ60ni encompassing several sources and sinks, as well as different oceanic water masses and contrasting biogeochemical domains. 6. conclusion from the above, it is evident that the development of new techniques not only provided answers to existing questions but also opened new topics and created new challenges. however, it is also increasingly clear that a complete and proper interpretation of the various processes during the geological past requires a multiproxy approach. the above-listed elements and their isotope signatures have the potential to explain a number of processes in both recent and palaeo-environments (e.g. redox conditions, the influence of organic matter, recrystallization, diagenesis, weathering, contribution of sources, etc.). combining such information with additional geochemical and mineralogical data will certainly ensure their more complete and correct interpretation. the lack of data is currently a limiting factor and calls for new studies that will expand our knowledge on non-traditional isotope signatures and provide new insights into many yet-unresolved geological problems. g eo lo gi a c ro at ic a 186 geologia croatica 74/2 acknowledgement the authors would like to acknowledge the valuable contributions of the anonymous reviewers and editors. funding: this research received no external funding. conflicts of interest: the authors declare no conflict of interest. references ahm, a.s.c., bjerrum, c.j., blättler, c.l., swart, p.k. & higgins, j.a. (2018): quantifying early marine diagenesis in shallow-water carbonate sediments.– geochim. cosmochim. acta, 236, 140–159. doi: 10.1016/j. gca.2018.02.042 andrews, m.g., jacobson, a.d., leh, g.o., horton, t.w. & craw, d. (2016): radiogenic and stable sr isotope ratios (87sr/86sr, δ88/86sr) as tracers of riverine cation sources and biogeochemical cycling in the milford sound region of fiordland new zealand. isotopes as palaeoceanographic tracers.– geochim. cosmochim. acta, 173, 284–303. doi: 10.1016/j.gca.2015.10.005 baconnais, i., rouxel, o., dulaquais, g. & boye, m. (2018): determination of the copper isotope composition of seawater revisited: a case study from the mediterranean sea.– chem. geol., 511, 465–480. doi: 10.1016/j. chemgeo.2018.09.009 blättler, c.l., miller, n.r. & higgins, j.a. (2015): mg and ca isotope signatures of authigenic dolomite in siliceous deep-sea sediments.– earth planet. sc. lett., 419, 32–42. doi: 10.1016/j.epsl.2015.03.006 böhm, f., gussone, n., eisenhauer, a., dullo, w.c., reynaud, s. & paytan, a. (2006): calcium isotope fractionation in modern scleractinian corals.– geochim. cosmochim. acta, 70/17, 4452–4462. doi: 10.1016/j. gca.2006.06.1546 bonnand, p., james, r.h., parkinson, i.j., connelly, d.p. & fairchild, i.j. (2013). the chromium isotopic composition of seawater and marine carbonates.– earth planet sc. lett., 382, 10–20. doi: 10.1016/j.epsl.2013.09.001 boyle, e.a., john, s., abouchami, w., adkins, j.f., echegoyen-sanz, y. et al. (2012): geotraces ic1 (bats) contamination-prone trace element isotopes cd fe pb zn cu and mo intercalibration.– limnol. oceanogr. meth., 10, 653–665. doi: 10.4319/lom.2012.10.653 bradbury, h.j. & turchyn, a.v. (2018): calcium isotope fractionation in sedimentary pore fluids from odp leg 175: resolving carbonate recrystallization.– geochim. cosmochim. acta, 236, 121–139. doi: 10.1016/j.gca.2018.01.040 brand, w.a., coplen, t.b., vogl, j., rosner, m. & prohaska, t. (2014): assessment of international reference materials for isotope-ratio analysis (iupac technical report).– pure appl. chem., 86/3, 425–467. doi: 10.1515/pac-20131023 coplen, t.b. (2011): guidelines and recommended terms for expression of stable‐isotope‐ratio and gas‐ratio measurement results.– rapid commun. mass spectrom., 25, 2538–2560. doi: 10.1002/rcm.5129 brazier, j.-m., schmitt, a.-d., gangloff, s., pelt, e., chabaux, f. & tertre, e. (2019): calcium isotopic fractionation during adsorption onto and desorption from soil phyllosilicates (kaolinite montmorillonite and muscovite).– geochim. cosmochim. acta, 250, 324–347. doi: 10.1016/j.gca.2019.02.017 bruggmann, s., scholz, f., klaebe, r.m., canfield, d.e. & frei, r. (2019): chromium isotope cycling in the water column and sediments of the peruvian continental margin.– geochim. cosmochim. acta, 257, 224–242. doi: 10.1016/j.gca.2019.05.001 cameron, v. & vance, d. (2014): heavy nickel isotope compositions in rivers and the oceans.– geochim. cosmochim. acta., 128, 195–211. doi: 10.1016/j. gca.2013.12.007 cameron, v., vance, d., archer, c. & house, c.h. (2009). a biomarker based on the stable isotopes of nickel.– p. natl. acad. sci. usa, 106/27, 10944–10948. doi: 10.1073/pnas.0900726106 chan, l.h., leeman, w.p. & plank, t. (2006): lithium isotopic composition of marine sediments.– geochem. geophys. geosy., 7/6, 1–25. doi: 10.1029/ 2005gc001202 chanda, p. & fantle, m.s. (2017): quantifying the effect of diagenetic recrystallization on the mg isotopic composition of marine carbonates.– geochim. cosmochim. acta, 204, 219–239. doi: 10.1016/j.gca.2017.01.010 ciscato, e.r., bontognali, t.r.r. & vance, d. (2018): nickel and its isotopes in organic-rich sediments: implications for oceanic budgets and a potential record of ancient seawater.– earth planet. sc. lett., 494, 239–250. doi: 10.1016/j. epsl.2018.04.061 coplen, t.b. (2011): guidelines and recommended terms for expression of stable‐isotope‐ratio and gas‐ratio measurement results.– rapid commun. mass spectrom., 25, 2538–2560. doi: 10.1002/rcm.5129 de souza, g.f., reynolds, b.c., kiczka, m. & bourdon, b. (2010): evidence for mass dependent isotopic fractionation of strontium in a glaciated granitic watershed.– geochim. cosmochim. acta, 74/9, 2596–2614. doi: 10.1016/j. gca.2010.02.012 fantle, m.s. & higgins, j. (2014): the effects of diagenesis and dolomitization on ca and mg isotopes in marine platform carbonates: implications for the geochemical cycles of ca and mg.– geochim. cosmochim. acta, 142, 458–481. doi: 10.1016/j.gca.2014.07.025 fantle, m.s., & tipper, e.t. (2014): calcium isotopes in the global biogeochemical ca cycle: implications for development of a ca isotope proxy.– earth-sci. rev., 129, 148–177. doi: 10.1016/j.earscirev.2013.10.004 fietzke, j. & eisenhauer, a. (2006): determination of temperature-dependent stable strontium isotope (88sr/86sr) fractionation via bracketing standard mc-icpms.– geochem. geophys. geosy., 7/8, q08009. doi: 10.1029/2006gc001243 gall, l., williams, h., siebert, c., halliday, a., herrington, r. & hein, j. (2013). nickel isotopic compositions of ferromanganese crusts and the constancy of deep ocean inputs and continental weathering effects over the cenozoic.– earth planet sc. lett., 375, 148–155. doi: 10.1016/j.epsl.2013.05.019 galy, a., bar-matthews, m., halicz, l., & o’nions, r.k. (2002). mg isotopic composition of carbonate: insight from speleothem formation.– earth planet sc. lett., 201/1, 105–115. doi: 10.1016/s0012-821x(02)00675-1 gilleaudeau, g.j., frei, r., kaufman, a.j., kah, l.c., azmy, k., bartley, j.k., chernyavskiy, p. & knoll, a.h. (2016): oxygenation of the mid-proterozoic atmosphere: clues from chromium isotopes in carbonates.– geochem. perspec. lett., 2, 178–187. doi: 10.7185/geochemlet.1618 gueguen, b., rouxel, o., rouget, m.-l., bollinger, c., ponzevera, e., germain, y. & fouquet, y. (2016): comparative geochemistry of four ferromanganese crusts from the pacific ocean and significance for the use of ni isotopes as palaeoceanographic tracers.– geochim. cosmochim. acta, 189, 214–235. doi: 10.1016/j.gca.2016.06.005 guo, b., zhu, x., dong, a., yan, b., shi, g. & zhao, z. (2019): mg isotopic systematic and geochemical applications: a critical review.– j. asian earth sci., 176, 368-385. doi: 10.1016/j.jseaes.2019.03.001 halicz, l., segal, i., fruchter, n., stein, m. & lazar, b. (2008): strontium stable isotopes fractionate in the soil environments?– earth planet sc. lett., 272/1–2, 406–411. doi: 10.1016/j.epsl.2008.05.005 higgins, j.a., blättler, c.l., lundstrom, e.a., santiago-ramos, d.p., akhtar, a.a., crüger, ahm, a.-s., bialik, o., holmden, c., bradbury, h., murray, s.t. & swart, p.k. (2018): mineralogy, early marine diagenesis, and the chemistry of shallow-water carbonate sediments.– geochim. cosmochim. acta, 220, 512–534. doi: 10.1016/j.gca.2017.09.046 hippler, d., eisenhauer, a. & nägle, t.f. (2006): tropical atlantic sst history inferred from ca isotope thermometry over the last 140 ka.– geochim. cosmochim. acta, 70, 90–100. doi: 10.1016/j.gca.2005.07.022. hu, z., hu, w., liu, c., sun, f., liu, y. & li, w. (2019): conservative behavior of mg isotopes in massive dolostones: from diagenesis to hydrothermal reworking.– sediment geol., 381, 65–75. doi: 10.1016/j.sedgeo.2018.12.007 kimmig, s.r. & holmden, c. (2017): multi-proxy geochemical evidence for primary aragonite precipitation in a tropical-shelf ‘calcite sea’ during the hirnantian glaciation.– geochim. cosmochim. acta, 206, 254–272. doi: 10.1016/j. gca.2017.03.010 krabbenhöf, a., eisenhauer, a., böhma, f., vollstaedt, h., fietzke, j., liebetrau, v., augustin, n., peucker-ehrenbrink, b., müller, m.n., horn, c., hansen, b.t., nolte, n. & wallmann, k. (2010): constraining the marine strontium budget with natural strontium isotope fractionations (87sr/86sr* δ88/86sr) of carbonates hydrothermal solutions and river waters.– geochim. cosmochim. acta, 74, 4097–4109. doi: 10.1016/j. gca.2010.04.009 li, w., bialik, o.m., wang, x., yang, t., hu, z., huang, q., zhao, s. & waldmann, n.d. (2019): effects of early diagenesis on mg isotopes in dolomite: the roles of mn(iv)-reduction and recrystallization.– geochim. cosmochim. acta, 250, 1–17. doi: 10.1016/j.gca.2019.01.029 li, w.-y., teng, f.-z., ke, s., rudnick, r.l., gao, s., wu, f.-y. & chappell, b.w. (2010): heterogeneous magnesium isotopic composition of the upper continental crust.– geochim. cosmochim. acta., 74/23, 6867–6884. doi: 10.1016/j. gca.2010.08.030 little, s.h., archer, c., milne, a., schlosser, c., achterberg, e.p., lohan, m.c. & vance, d. (2018): paired dissolved and particulate phase cu isotope distributions in the south atlantic.– chem. geol., 502, 29–43. doi: 10.1016/j.chemgeo.2018.07.022 little, s.h., vance, d., mcmanus, j., severmann, s. & lyons, t.w. (2017): copper isotope signatures in modern marine sediments.– geochim. cosmochim. acta, 212, 253–273. doi: 10.1016/j.gca.2017.06.019 little, s.h., vance, d., walker-brown, c. & landing, w. (2014): the oceanic mass balance of copper and zinc isotopes investigated by analysis of their inputs and outputs to ferromanganese oxide sediments.– geochim. cosmochim. acta, 125, 673–693. doi: 10.1016/j.gca.2013.07.046 g eologia c roatica 187fiket et al.: non-traditional stable isotope signatures in geological matrices as a tool for interpreting environmental changes – a review maréchal, c.n., télouk, p. & albarède, f. (1999): precise analysis of copper and zinc isotopic compositions by plasma-source mass spectrometry.– chem. geol., 156, 251–273. doi: 10.1016/s0009-2541(98)00191-0 míková, j. (2012): strontium isotopic composition as tracer of weathering processes, a review with respect to james ross island, antarctica.– czech polar rep., 2/1, 20–30. doi: 10.5817/cpr2012-1-3 moynier, f., agranier, a., hezel, d.c. & bouvier, a. (2010): sr stable isotope composition of earth, the moon, mars, vesta and meteorites.– earth planet. sci. lett., 300/3–4, 359–366. doi: 10.1016/j.epsl.2010.10.017 moynier, f., vance, d., fujii, t. & savage, p. (2017): the isotope geochemistry of zinc and copper.– rev. mineral. geochemistry, 82/1, 543–600. doi: 10.2138/rmg.2017.82.13 nägler, t., eisenhauer, a., muller, a., hemleben, c. & kramers, j. (2000): the δ44ca temperature calibration on fossil and cultured globigerinoides sacculifer: new tool for reconstruction of past sea surface temperatures.– geochem. geophys. geosy., 1, 2000gc000091. doi: 10.1029/2000gc000091 ockert, c., gussone, n., kaufhold, s. & teichert, b.m.a. (2013): isotope fractionation during ca exchange on clay minerals in a marine environment.– geochim. cosmochim. acta, 112, 374–388. doi: 10.1016/j.gca.2012.09.041 oeser, r.a. & von blanckenburg, f. (2020): strontium isotopes trace biological activity in the critical zone along a climate and vegetation gradient.– chem. geol., 119861. doi: 10.1016/j.chemgeo.2020.119861 ohno, t. & hirata, t. (2007): simultaneous determination of mass-dependent isotopic fractionation and radiogenic isotope variation of strontium in geochemical samples by multiple collector-icp-mass spectrometry.– anal. sci., 23/11, 1275–1280. doi: 10.2116/analsci.23.1275 penniston-dorland, s., liu, x.-m. & rudnick, r.l. (2017): lithium isotope geochemistry.– rev. mineral geochem., 82/1, 165–217. doi: 10.2138/ rmg.2017.82.6 pistiner, j.s. & henderson, g.m. (2003): lithium-isotope fractionation during continental weathering processes.– earth planet sc. lett., 214, 327–339. doi: 10.1016/s0012-821x(03)00348-0 pogge von strandmann, p.a.e., burton, k.w., james, r.h., van calsteren, p. & gislason, s.r. (2010): assessing the role of climate on uranium and lithium isotope behavior in rivers draining a basaltic terrain.– chem. geol., 270/1–4, 227–239. doi: 10.1016/j.chemgeo.2009.12.002 pogge von strandmann, p.a.e., burton, k.w., james, r.h., van calsteren, p., gislason, s.r. & mokadem, f. (2006): riverine behaviour of uranium and lithium isotopes in an actively glaciated basaltic terrain.– earth planet sc. lett., 251/1–2, 134–147. doi: 10.1016/j.epsl.2006.09.001 pogge von strandmann, p.a.e., burton, k.w., james, r.h., van calsteren, p., gislason, s.r. & sigfússon, b. (2008): the influence of weathering processes on riverine magnesium isotopes in a basaltic terrain.– earth planet sc. lett., 276/1–2, 187–197. doi: 10.1016/j.epsl.2008.09.020 pogge von strandmann, p.a.e., schmidt, d.n., planavsky, n.j., wei, g., todd, c.l. & baumann, k.-h. (2019). assessing bulk carbonates as archives for seawater li isotope ratios.– chem. geol., 530, 119338. doi: 10.1016/j.chemgeo.2019.119338 ryan, b.m., kirby, j.k., degryse, f., scheiderich, k. & mclaughlin, m.j. (2014): copper isotope fractionation during equilibration with natural and synthetic ligands.– environ. sci. technol., 48/15, 8620-8626. doi: 10.1021/ es500764x saenger, c. & wang, z. (2014): magnesium isotope fractionation in biogenic and abiogenic carbonates: implications for palaeoenvironmental proxies.– quat. sci. rev., 90, 1–21. doi: 10.1016/j.quascirev.2014.01.014 sauzéat, l., rudnick, r.l., chauvel, c., garcon, m. & tang, m. (2015): new perspectives on the li isotopic composition of the upper continental crust and its weathering signature.– earth planet sc. lett., 428, 181–192.82. doi: 10.1016/j.epsl.2015.07.032 scheiderich, k., amini, m., holmden, c. & francois, r. (2015): glo bal variability of chromium isotopes in seawater demonstrated by pacific atlantic and arctic ocean samples.– earth planet sc. lett., 423, 87–97. doi: 10.1016/j.epsl.2015.04.030 scher, h.d., griffith, e.m. & buckley, w.p.jr (2013): accuracy and precision of 88sr/86sr and 87sr/86sr measurements by mc-icpms compromised by high barium concentrations.– geochem. geophys. geosy., 15, 499–508. doi: 10.1002/2013gc005134 schoenberg, s., zink, m., staubwasser, m. & von blanckenburg, f. (2008): the stable cr isotope inventory of solid earth reservoirs determine by double spike mc-icp-ms.– chem. geol., 249/3–4, 294–306. doi: 10.1016/j. chemgeo.2008.01.009 semenishchev, v.s. & voronina, a.v. (2020): isotopes of strontium: properties and applications.– in: pathak, p. & gupta, d.k. (eds.): strontium contamination in the environment, springer international publishing. semeniuk, d., maldonado, m.t. & jaccard, s.l. (2016): chromium uptake and adsorption in marine phytoplankton – implications for the marine chromium cycle.– geochim. cosmochim. acta, 184, 41–54. doi: 10.1016/j. gca.2016.04.021 shalev, n., gavrieli, i., halicz, l., sandler, a., stein, m. & lazar, b. (2017): enrichment of 88 sr in continental waters due to calcium carbonate precipitation.– earth planet. sci. lett., 459, 381–393. doi: 10.1016/j.epsl.2016.11.042 takano, s., tanimizu, m., hirata, t. & sohrin, y. (2014): isotopic constraints on biogeochemical cycling of copper in the ocean.– nat. commun., 5, 5663. doi: 10.1038/ncomms6663 teng, f.z. (2017): magnesium isotope geochemistry.– rev. mineral. geochem., 82/1, 219–287. doi: 10.2138/rmg.2017.82.7 teng, f.-z., dauphas, n. & watkins, j.m. (2017): non-traditional stable isotopes: retrospective and prospective.– rev. mineral. geochem., 82/1, 1–26. doi: 10.2138/rmg.2017.82.1 teng, f.-z., mcdonough, w.f., rudnick, r.l., dalpé, c., tomascak, p.b., chappell, b.w. & gao, s. (2004): lithium isotopic composition and concentration of the upper continental crust.– geochim. cosmochim. acta, 68/20, 4167–4178. doi: 10.1016/j.gca.2004.03.031 thompson, c.m. & ellwood, m.j. (2014): dissolved copper isotope biogeochemistry in the tasman sea, sw pacific ocean.– mar. chem., 165, 1–9. doi: 10.1016/j.marchem.2014.06.009 vance, d., archer, c., bermin, j., perkins, j., statham, p.j., lohan, m.c., ellwood, m.j. & mills, r.a. (2008). the copper isotope geochemistry of rivers and the oceans.– earth planet sc. lett., 274/1–2, 204–213. doi: 10.1016/j.epsl.2008.07.026 vollstaedt, h., eisenhauer, a., wallmann, k., böhm, f., fietzke, j., liebetrau, v., krabbenhöft, a., farkaš, j., tomašových, a., raddatz, j. & veizer, j. (2014): the phanerozoic δ88/86sr record of seawater: new constraints on past changes in oceanic carbonate fluxes.– geochim. cosmochim. acta, 128, 249–265. doi: 10.1016/j.gca.2013.10.006 wakaki, s., obata, h., tazoe, h. & ishikawa, t. (2017): precise and accurate analysis of deep and surface seawater sr stable isotopic composition by double-spike thermal ionization mass spectrometry.– geochem. j., 51/3, 227–239. doi: 10.2343/geochemj.2.0461 wimpenny, j., colla, c.a., yin, q.-z., rustad, j.r. & casey, w.h. (2014): investigating the behaviour of mg isotopes during the formation of clay minerals.– geochim. cosmochim. acta, 128, 178–194. doi: 10.1016/j.gca.2013.12.012 www.geologia-croatica.hr abstract a consanguineous origin of the sparry siderite and magnesite mineralizations of the eastern alps has been repeatedly discussed in the past, often without the back-up of sound scientific arguments. here, it is shown that the characteristics of these mineralizations including structures, fluid parameters, timing etc. are amazingly similar suggesting in fact the genetic linkage of these deposits. the siderite as well as the magnesite mineralizations of the eastern alps exhibit metasomatic-epigenetic structures of lens-shaped orebodies with dolomitic alteration rims as dominant features. the basic chemical characteristics of the ore forming fluids in these mineralizations are those of highly fractionated hypersaline fluids exhibiting all the features of residual bittern brines. fluid invasion and mineralization structures strictly depend on the original lithology of the host rocks, mainly carbonatic sedimentary rocks. in late triassic times, these buried evaporitic brines were mobilized either by magmatic/metamorphic processes in the underlying crystalline units or by the superimposed sedimentary upload of the triassic platform carbonates thus leading to magnesite formation. initially these residual, bittern brines were completely free of fe and rich in mg suitable for the formation of magnesite. deeper and more extensive circulation of these fluids and their interaction with the host-rock, resulted in the uptake of fe and the formation of siderite. keywords: siderite, magnesite, mineralizing fluids article history: received october 15, 2015 revised and accepted january 21, 2016 avaliable online february 29, 2016 1. introduction numerous magnesite and siderite mineralizations of various sizes can be observed in the eastern alps of austria (fig. 1), some of them were of considerable economic importance and were exploited. the minerogenetic map of austria exhibits their locations. today, only one siderite mine, the erzberg siderite deposit, situated in the province of styria, is in operation. the present austrian iron production is about 750.000 tpa (fe-content) and is exclusively produced from this mine. the well-developed austrian magnesite industry is of worldwide importance, and is to a large extent still based on the austrian mines. magnesite production in austria is approximately 750.000 tpa (ranked 5th worldwide) and is mined from 10 different deposits. similar mineralizations occur in upper carboniferous strata of the gemeric units of slovakia, which can be directly compared to the greywacke zone. the discussion about the genesis of these magnesite and siderite mineralizations throughout previous decades is very similar to the controversial views of the austrian examples and reflects the changing opinions concerning these mineralizations throughout the history of their investigation. it is beyond the scope here to give a complete review of the innumerable publications on the siderite and magnesite deposits of the eastern alps, so only a brief summary is given. however, 31-38 9 figs. doi: 10.4154/gc.2016.03 figure 1. part of the minerogenetic map of austria showing the feand magnesite mineralizations of the greywacke zone (weber, 1997). genetic concepts on the formation of the austrian magnesite and siderite mineralizations in the eastern alps of austria walter prochaska university of leoben, department of geological sciences, a-8700 leoben, austria 32 vol. 69/1 during recent decades some considerable progress was made in the understanding of these mineralizations using modern scientific methods. therefore the main focus of this paper is to discuss the results obtained by the investigation and characterization of the chemistry of the fluid inclusions forming these mineralizations. furthermore, direct radiometric age determination of the carbonate minerals of the hydrothermal events during recent years contributed substantially to the revised models of oreformation. finally, on the basis of these new results, an attempt is made to demonstrate that there is a genetic link between the carbonate-hosted sparry magnesite and the siderite mineralizations of the eastern alps. the arguments are mainly based on the investigations of the fluid chemistry from inclusions that allow characterization of the ore forming fluids showing an overall evaporitic signature of the hydrothermal fluids responsible for these mineralizations. another crucial aspect for the genesis of both siderite and magnesite deposits is the timing of the mineralizing event. the focus of this paper is on the magnesite and siderite mineralizations of the palaeozoic series of the eastern alps. the important siderite/haematite iron-ore province of hüttenbergwaldenstein in the austroalpine crystalline complex is not discussed in this paper. this iron-ore province is related to hydrothermal processes in connection to young tectonic activity without any relation to the mineralizations in the palaeozoic series discussed here. 2. genetic models proposed in the past it is far beyond the scope of this chapter even to list the enormous amount of papers, published on the austrian siderite and magnesite mineralizations since the start of modern geoscientific investigation in approximately 1850. therefore only the general trend in the genetic opinion is referred to and discussed. opinions concerning the genesis of the siderite mineralizations of the greywacke zone are inconsistent (cum. cit. tollmann, 1977), and discussion about this topic is a longstanding tradition. different genetic models, including a synsedimentary origin or an eoalpine vein-type and a metasomatic mineralization type have been proposed in the past. early workers (e.g. schouppe, 1854; vacek, 1903) on this topic favoured syngenetic models, and at the turn of the century epigenetic models for the erzberg type mineralization were proposed. more recent research concentrated on the investigation of structural and geochemical features and also on comparative studies (e.g. pohl, 1986) of the siderite mineralizations. in the 1970s, syngenetic models were favoured for the erzberg mineraliza tions mainly because of the findings of minor banded ore structures that were interpreted as primary sedimentary ore bands (beran, 1973, 1975, 1977, 1979a, 1979b; beran & thalmann, 1977, 1978). following these arguments schulz et al. (1997) described ore textures of the erzberg deposit and postulated a marine-synsedimentary origin for the mineralization. recently an epigenetic genesis for siderite mineralization in the greywacke zone was reintroduced on the basis of microthermometric, geochemical, and isotope data (frimmel, 1988; prochaska, 1991; spindler, 1992; belocky, 1992; pohl & belocky, 1994; laube et al., 1995; prochaska, 1997). these authors generally postulate an epigenetic origin, nevertheless there is no unanimous opinion concerning the most important metallogenetic features, the timing of the hydrothermal event, and the origin of the hydrothermal fluids. similarly, there is no consensus on the genetic model and not even about the principal mechanisms for magnesite mineralization. starting soon after the discovery of the world´s first magnesite deposits in the eastern alps after 1850, syngenetic models (e.g. rumpf, 1873; leitmeier, 1917) and epigenetic models (e.g. koch, 1893; vacek, 1903; redlich, 1907) were published. starting in the 1950s, a general trend towards syngenetic and early diagenetic models can be observed (de llarena, 1953; leitmeier & siegl, 1954). niedermayr (1989) argued for synsedimentary or early diagenetic genesis for magnesite mineralization in the permian series of the eastern alps and extended this model to the alpine sparry magnesites. pohl & siegl presented an extensive overview of the magnesite mineralizations of the eastern alps in 1986. möller (1989) edited a monograph on magnesite summarizing the recent geochemical and mineralogical facts on the “magnesite problem”. during more recent years, new fluid inclusion and isotope data for the sparry magnesite deposit of the eastern greywacke zone provide strong evidence for formation of the magnesite deposits by metasomatic replacement due to infiltrating salinar residual brines which originated in the upper permian/lower triassic (e.g. prochaska, 2000; prochaska, 2001; prochaska & henjes-kunst, 2007). these observations are considered to be of fundamental importance not only for the genetic aspects of carbonate-hosted sparry magnesite deposits but also hinting towards a consanguineous origin of the magnesite and siderite deposits of the eastern alps in general. very recent results obtained by radiometric age dating of the carbonate formation provide proof for triassic ore formation (henjes-kunst et al., 2014; prochaska & henjeskunst, 2009). earlier workers, especially petrascheck (1926, 1932) in his classic work on the metallogenetic zonation in the eastern alps, already mentioned a consanguineous origin of the alpine sparry magnesite mineralizations and the siderite deposits as proposed here. also other early investigators (redlich, 1907, 1909; clar, 1956; friedrich, 1959, etc.) generally argued for hydrothermal fluids of different origin like magmatic or meta morphic fluids of alpine (neogene) age. nevertheless these concepts never gained general acceptance at that time. 3. geologic position and structural features of the magnesite and siderite mineralizations the magnesite and siderite mineralizations occur in the greywacke zone, which is the palaeozoic basement of the mesozoic platform carbonates of the upper austroalpine nappe. fundamental overviews of the geology and tectonostratigraphy of the greywacke zone were given by schönlaub (1982), neubauer (1994) and neubauer et al. (1994). the rock series of the greywacke zone range from the ordovician to the carboniferous and com33 prochaska walter: genetic concepts on the formation of the austrian magnesite and siderite mineralizations in the eastern alps of austria prise carbonates, metapelites, and metamorphosed acid volcanics. the grade of metamorphism is generally lower greenschist facies both in the variscan and in the eoalpine tectonometamorphic event. the tectonically lower veitsch nappe is affected only by the alpine metamorphism of greenschist facies grade. generally, magnesite mineralizations tend to form irregular lenses and stocks whereas no veins are known. the siderite deposits occur as stocks in the carbonate environment and as veins in different host-rock lithologies (see below). 3.1. magnesite mineralizations in the eastern greywacke zone, carbonate-hosted sparry magnesite mineralization occurs mainly in lower carboniferous strata of the veitsch nappe. a set of lens-shaped magnesite bodies of various sizes can be observed in a sequence of sericite schists, greywackes, conglomerates and metatuffs. carbonate series hosting the magnesite bodies are of upper tournéan/viséan age and characterise shallow water, marine environments. an exception is the breitenau mine, which is located in a palaeozoic series of deep-water environments of probably silurian to lower devonian age. one of the most prominent examples of sparry magnesite deposits in the eastern alps is the abandoned veitsch mine, which is the type locality of carbonate hosted sparry magnesite deposits. in the western greywacke zone, magnesite can be seen in palaeozoic strata of a remarkable age spread from upper silurian to middle devonian series. the most abundant host-rocks of magnesite mineralization in this area are dolomites of the lower to middle devonian, but also black dolomite of silurian age hosts magnesite occurrences (e.g. entachen alm). siegl (1969) reported magnesite components in the permian basal breccia of the alpidic orogenic cycle. the position of the highly metamorphosed radenthein deposit is unclear. some authors (angel et al., 1953) consider it to be a tectonic wedge of upper austroalpine palaeozoic rocks thrust into the tectonically deeper austroalpine crystalline units during the alpine tectonic event while others (tufar et al., 1989) regard it as an original member of the rock sequence. the most obvious and striking textural feature of these mineralizations is the coarse-grained, sparry structure of the magnesites. these “pinolitic” structures are defined by coarse-grained magnesite crystals which occur in a dark/black fine-grained matrix. these structures are especially developed when the hostrocks are grey to black marbles. it is obvious that this structure is due to the hydrothermal growth of coarse-grained, white magnesite crystals, while the organic pigment is concentrated in the fine-grained matrix. the hydrothermal-epigenetic nature of the magnesite mineralizations is reflected by the fact that the orebodies are enveloped by alteration zones of variable width. hydrothermal, mottled dolomite, often exhibiting banding and zebra structures of several metres thickness, prevails in these zones. these reaction fronts can sometimes be reduced to a few cm as demonstrated in fig. 3. the first signs of hydrothermal substitution forming sparry dolomite and magnesite on account of the hostrock calcite are small specs of pyrite formed in the host-rock in the immediate vicinity of the reaction front testifying to the reducing nature of the hydrothermal fluid (fig. 4). figure 2. pinolitic sparry magnesite with late quartz-veins of eoalpine age from the veitsch deposit. figure 4. the reducing nature of the ore forming fluid causes a pyrite halo in the host-rock carbonate before the „metasomatic front“ while pyrite is usually lacking in these host-rocks. figure 3. „metasomatic front“ between the fine-grained host-rock marble and the sparry magnesite. an intermediate reaction product between the magnesite and the host-rock is sparry dolomite. 34 vol. 69/1 3.2. siderite mineralizations the siderite mineralizations of the eastern alps are concentrated in two different metallogenetic provinces, the hüttenbergwaldenstein fe-ore province and the erzberg-type mineralizations of the greywacke zone (fig. 1). this paper refers only to the latter fe-ore province. many abandoned deposits and the erzberg mine belong to this metallogenetic province. the fact that these mineralizations do not occur in deeper tectonic units of the greywacke zone supports a timing of mineralization before the stacking of the austroalpine nappes. another significant feature is that this type of mineralization shows indications of a continuation into deeper parts of the overlying lower triassic carbonates of the northern calcareous alps of the upper austroalpine units, however, the thick units of platform carbonates of the northern calcareous alps were not affected by the mineralizing events. the other set of siderite/haematite mineralizations is concentrated in the amphibolite facies metamorphic complexes of the austroalpine crystalline units to the south. the most important mineralization of this group is the former siderite mine of „hüttenberg“ which was abandoned in the 1970`s. this tertiary siderite province is of different origin to the greywacke zone deposits and is not covered further in this paper. the siderite occurrences in the greywacke zone are neither stratabound nor stratiform and exhibit different modes of occurrence. host-rock lithology strongly influences the structure of the mineralizations. vein type mineralizations usually occur in competent host-rocks such as ordovician quartz porphyries or palaeozoic metapelites and sandstones, while more reactive host-rocks including the devonian carbonates and permoscythian carbonate conglomerates host metasomatic bodies, lenses and stocks of siderite. 3.2.1. siderite veins in ordovician quartz porphyries underground exposures of this ore type are best exposed in the abandoned schendleck siderite mine (fig. 1.). the structure of this mineralization is that of a typical vein type deposit with siderite-quartz veins cross-cutting ordovician quartz porphyries exhibiting prominent alteration zones with intense sericitization. these structures were previously interpreted (baumgartner, 1976) as tuff layers, and accordingly a synsedimentary formation was deducted. the abandoned hirschwang, altenberg and grillenberg siderite mines are in close vicinity of this mineralization, but hosted by permoskythian siliciclastic series. in the area of the erzberg siderite mine, which is generally hosted by devonian limestones (see below) many smaller siderite veins are located in altered quartz porphyry host-rock. 3.2.2. metasomatic siderite bodies in devonian limestones and upper permian carbonate conglomerates the most prominent example of this type of siderite mineralization is the erzberg siderite mine in the province of styria. the siderite orebodies are generally hosted by fine-grained limestones of devonian age. metasomatic-epigenentic structures are dominant and usually coarse-grained siderite ore exhibits discordant contacts with the unmineralized limestones. the only ore mineral is siderite, but frequently ankerite haloes around the siderite orebodies can be observed. fig. 5 shows the metasomatic front between the carbonatic breccia and the orebody cutting single components of the breccia, demonstrating clearly the metasomatic-hydrothermal nature of the mineralization. furthermore, no single siderite components in the calcite breccia are known as should be the case with a pre-permian siderite mineralization. eoalpine tectonic structures and weak metamorphic overprints are described from the erzberg deposit. 3.2.3. vein type mineralizations in permoskythian siliciclastic host-rocks different occurrences of this type of mineralization were investigated within the course of this work (gollrad, grillenberg, sohlenalm, altenberg). the mineralizations are usually hosted by permoskythian quartz-conglomerates (präbichel series), and sandstones (werfen formation) forming the base of the upper austroalpine northern calcareous alps. the usual structure is that of siderite veins cross-cutting permoskythian sandstones and conglomerates, but in some cases haematite is the dominant ore mineral. the former gollrad siderite/haematite mine was recently reinvestigated for its economic potential of specular haematite. 4. chemical characteristics of inclusion fluids of the siderite and magnesite mineralizations because of the conformable chemical characteristics of the mine ralizing fluids the results concerning the magnesite as well as the siderite mineralizations are presented and discussed together in this chapter. in order to characterize the nature of the ore-forming fluids the chemistry of the inclusion fluids of the siderite and magnesite deposits was investigated by mechanical extraction and subsequent analysis (polgari et al., 2010; prochaska, 2012). the method applied here is based on the “crush-leach” extraction of the inclusion fluids and chemical analyses by ion chromatography of the most diagnostic components. the methodological approach used is modified after bottrell et al. (1988) and is explained in detail in prochaska (2000). the characterization of the total dissolved solutes chemistry of inclusion fluids was first and most widely applied to the study figure 5. the metasomatic siderite front in the mineralized “basisbrekzie” cuts the single carbonate components thus proving the hydrothermal metasomatic nature of the mineralization. 35 prochaska walter: genetic concepts on the formation of the austrian magnesite and siderite mineralizations in the eastern alps of austria of mississippi valley type pb-zn mineralization in order to obtain information on the sources of solutes in ore-forming brines and to explore genetic linkages among deposits (e.g. hall & friedman, 1963; viets & leach, 1990; böhlke et al., 1992; kesler et al., 1996). despite the similar ionic radii of chlorine (1.81 å) and bromine (1.96 å) the fractionation of these elements in evaporitic processes is quite different. in an initial stage of evaporation na, cl, and br are concentrated in a hypersaline environment, and their ratios do not change. at an evaporation index of > 10, halite is precipitated. br has a very conservative behaviour and is not incorporated into the halite lattice. at an evaporation index of approx. 70, mg-salts start to precipitate and br is still concentrated in the residual brines. the cation systematics changed from an original na preponderance to mg and k dominated systems (mccafferey et al., 1987). on the cl/br and na/br molar ratio diagrams for magnesite (fig. 6) and siderite (fig. 7) the evolution of the fluids by fractionation of halite from seawater is demonstrated. according to the fractionation behaviour of the na-cl-br system explained earlier, the composition of an evaporating brine shifts along the “evaporation trend“ when halite starts to precipitate at an evaporation index of about 10. in contrast, fluids percolating through the crust acquiring salinity by dissolution of halite, plot towards higher cl/br and na/br molar ratios above the seawater composition, and their composition is close to the „halite dissolution trend“. in the cl/br and na/br molar ratio diagrams for magnesite as well as siderite (figs. 6, 7) the inclusion chemistry of the investigated samples clearly plot on the seawater evaporation trend, thus indicating an origin of the fluids from subaerial evapo-concentration of seawater. in general the magnesite fluids show a stronger fractionation and the composition of the fluids plot on the very end of the evaporation trend. the plots of the dolomites of the alteration zone exhibit a transitional position between the magnesite composition and that of seawater. despite the general similarity and the overall evaporitic nature of the fluids, the siderite fluid composition shows in some cases an intermediate position between extreme fractionation and seawater composition. in general the erzberg-fluids are highly fractionated and plot at the end of the evaporation trend (fig. 7) while the projection points of smaller, vein-type systems (e.g. altenberg, sohlenalm…) are not as br-rich as the big and voluminous erzberg siderites. the reasons for these fluid characteristics may be the result of the differences in the degree of the fluid-rock interaction where in the smaller systems the composition of the fluid is altered while in the bigger systems the original fluid characteristics prevail. a prerequisite for the formation of hydrothermal-metasomatic deposits described here is a highly saline fluid capable of leaching fe from the host-rocks while percolating through the crust. in the case of the austroalpine sparry carbonate deposits the ore-forming fluids originally were bittern brines. however, the siderite deposits in tunesia and algeria/north africa, investigated by pohl et al. (1986) exhibit highly saline fluids, which were generated by partial dissolution of salt diapirs. accordingly these fluids are characterized by extremely high cl/br and na/br ratios (prochaska unpublished) and plot on the halite dissolution trend. 5. timing of the mineralizing event timing of the mineralization is one of the most important pieces of information needed to establish a genetic model within the geodynamic frame of the alpine or prealpine orogenic cycles, and therefore detailed investigations on radiometric dating were carried out during recent years. the fact that the mineralized structures and the mineralizations cut permo-mesozoic strata exclude a syngenetic devonian formation for these deposits. however, the eoalpine metamorphic event is considered by some authors to be responsible for modification and remobilization of early syngenetic mineralizations finally producing epigentic vein type deposits. in this study no indication of two fundamentally different sets of fluid compositions (e.g. marinesedimentary and alpine hydrothermal) in the ore minerals (siderite and magnesite) were discovered. there are some localities where the mineralized devonian limestones can be found in close proximity to totally unmineralized carboniferous limestones of the tectonically deeper veitsch nappe. in the case of an figure 6. na-cl-br ratios of the magnesite mineralizations of the eastern alps. the fluid composition clearly plots on the very end of the seawater evaporation trend proving the evaporitic origin of the fluids. host-rock limestones are relatively close to seawater composition as well as the fluid composition of the eoalpine quartz-veins (see also fig. 3). figure 7. na-cl-br ratios of the erzberg type siderite mineralizations. the fluid composition plots on the seawater evaporation trend. 36 vol. 69/1 extensive cretaceous metamorphic mobilization, the mineralized structures should also cut the tectonic units. however, all observations support the formation of the siderites before the alpine stacking of the nappes. some attempts have been made to obtain radiometric ages from sericites from the alteration zones of a siderite mineralization in the quartz porphyries (prochaska et al., 1996). a plateau age (ar-ar) of approximately 160 ma for the schendleck deposit was calculated. this age seems to be of some regional importance at the eastern margin of the eastern alps and is probably not the age of the hydrothermal ore-forming event. it coincides with an extensional phase in the austroalpine area due to the opening of the south penninic ocean. furthermore, a prominent rejuvenation due to the cretaceous metamorphic event (~90 ma) can be observed from the ar-ar investigations. consequently, from a geological point of view and from ar-ar data, the siderite-forming hydrothermal activity is not older than permoskythian and predates the eoalpine tectono-metamorphic event. essential progress on the age determination of the hydrothermal event responsible for the formation of the siderite and magnesite deposits of the eastern alps was the direct age dating of the carbonate minerals using the sm-nd radiometric system. during recent years radiometric information of some magnesite and siderite mineralizations were obtained and the formation ages cluster in the middle to upper triassic (figs. 8, 9). the method is explained comprehensively in henjeskunst et al. (2014) where a detailed investigation and a sound model for the formation of the breitenau magnesite deposit is presented. the sm-nd isochron age for this deposit is 222.5 ± 9.8 ma (fig. 8), which coincides very well with the unpublished isochron age for the wald/schober magnesite deposit of the greywacke zone with an age of approx. 220 ma. prochaska & henjes-kunst (2009) published an isochron age of 208 ± 22 ma (fig. 9) for the erzberg siderite deposit, which is in the range of the above mentioned magnesite deposits. 6. genetic model the genetic model presented here is based on the following observations: 1. the mineralizing event is post-variscan and pre-eoalpine because of the lack of siderite components in upper permian variscan basal conglomerates and the termination of hydrothermal features at alpine nappe boundaries. 2. in general the magnesite as well as the siderite mineralizations are neither stratabound nor stratiform. 3. the high salinity of the fluids and especially the fractionated, br-rich composition indicate that the mineralizing fluids were originally oxidized evaporitic, bittern brines which, while percolating through the crust became modified and reduced by water-rock reactions thus facilitating the capability to take up fe by leaching the host-rocks. 4. the sharp transition in the fluid composition (evapo-concentrations of seawater) between marine host-rock carbonates and the mineralizations is not compatible with a simple marine-sedimentary model. 5. the structure of the mineralizations is hydrothermalmetasomatic. no indications of a synsedimentary concentration of mg or fe can be observed. 6. radiometric dating provides proof for the formation of these mineralizations in the upper triassic. only in one case so far (hohentauern) has a late carboniferous to early permian age been reported by azim zadeh et al. (2015). in permian (to lower triassic) times evaporitic basins are ubiquitous in the austroalpine realm. deposition of thick series of evaporites is widespread in the permoscythian strata of the upper austroalpine unit. high degrees of evaporation (evaporation index 20 to 90) produced residual „bitterns“ with high salinities and high concentrations of br, mg, k, and so4 in the fluids. the peculiar fluid composition of the siderite and magnesite mineralizations can only be achieved in the wide evaporitic areas during the permo-mesozoic of the eastern alps. figure 8. sm-nd isochron of the breitenau magnesite deposit (henjes-kunst et al., 2014). for explanation see text. figure 9. sm-nd isochron of the siderites from the erzberg deposit (prochaska & henjes-kunst, 2009). for explanation see text. 37 prochaska walter: genetic concepts on the formation of the austrian magnesite and siderite mineralizations in the eastern alps of austria for the earlier magnesites (e.g. hohentauern), azim zadeh et al. (2015) propose an intraformational circulation of carboniferous evaporitic fluids causing metasomatic replacement of the host-rocks. however, extensive evaporitic systems which could produce brines with the corresponding high evaporation index, are not known so far in the carboniferous. for the siderite and magnesite deposits of middle to upper triassic age, two genetic models are plausible: high heat flow in the rift-environment induced hydrothermal convection systems mobilizing the residual evaporitic brines. lithospheric extension and long-lasting thermal activity related to igneous and metamorphic activities are documented in the basement rocks of the adriatic plate (thöni, 2002). mineral assemblages are reported in rocks ranging from 285 to 225 ma in age. generally this process can be responsible for the formation of the siderite and magnesite mineralizations in the upper triassic. another possibility for mobilizing the palaeobrines of upper permian to lower triassic age in the upper triassic is the dewatering of the sedimentary basins by the increasing load caused by the sedimentation of the platform carbonates of several km in thickness, triggering the upward movement of the fluids. of course these two mechanisms could have operated in concert. initially these fluids are ± free of fe and rich in mg with the capacity to transform the carbonatic host-rocks into magnesite. when these fluids travel longer distances through the crust, diagenetic reactions and host-rock alterations changed these brines into acidic and reducing fluids with the capacity of leaching fe from the country rocks, with the corresponding metasomatic product being siderite. this is compatible with the generally higher formation temperatures of siderite showing the formation of the fe-carbonates in deeper levels where higher temperatures prevail. vein-type siderite-haematite-sulfide mineralizations were formed in the metapelitic and metavolcanic host-rocks. within the devonian platform carbonates metasomatic siderite bodies were formed. metasomatism and mimetic crystallization of the marine host-rock carbonates often preserved primary sedimentary textures very well, which led earlier researchers to postulate syngenetic models. however, the proposed hydrothermal-metasomatic model of permoscythian evolved evaporitic brines being mobilized in the upper triassic can explain all the observed features of the siderite and magnesite mineralizations of the greywacke zone regardless of their stratigraphic and tectonic position. this model is consistent with features such as the overall high salinity of the fluids, the uniform and special fluid chemi stry and the published srand stable isotope ratios which cannot be explained by either sedimentary scenarios or by alpine remobilization models. a phenomenon that cannot be explained satisfactorily so far is the observation that the magnesite deposits exclusively occur in the lower tectonic unit of the greywacke zone (carboniferous veitsch nappe) while the siderite mineralizations are strictly bound to the higher unit (paleozoic noric nappe). a more detailed knowledge of the palaeogeography of the upper triassic is needed to elucidate this problem. references angel, f., awerzger, a., kuschinsky, a. & meixner, h. (1953): die magnesitlagerstätte milstätter alpe bei radenthein.– carinthia ii, 143, 98–118. azim zadeh, a.m., ebner, f. & jiang, s. (2015): mineralogical, geochemical, fluid inclusion and isotope study of hohentauern/sunk sparry magnesite deposit (eastern alps/austria): implications for a metasomatic genetic model.– mineralogy and petrology, 109/5, 555–575. baumgartner, w. (1976): zur genese der erzlagerstätten der östlichen grauwackenzone und der kalkalpenbasis etc.– bhm, 121, 51–54. belocky, r. (1992): regional vergleichende untersuchung lagerstättenbildender fluide in den ostalpen als hinweis auf eine mögliche metamorphe ableitung.– unpubl. thesis, univ. braunschweig, 103 p. beran, a. (1973): vorläufige mitteilung über mikrosondenuntersuchungen an einigen ankeriten und sideriten vom steirischen erzberg.– österr. akad. wiss., math.-naturwiss. kl., 3, 19–20. beran, a. (1975): mikrosondenuntersuchungen von ankeriten und sideriten des steirischen erzberges.– tmpm, 22, 250–265. doi: 10.1007/bf01087844 beran, a. (1977): die kluftankerite des steirischen erzberges und ihre mögliche verwendung als geothermometer.– mineral. deposita, 12, 90–95. beran, a. (1979 a): die stellung der ankeritgesteine im rahmen der genese von sideritlagerstätten der östlichen grauwackenzone.– tmpm, 26, 217–233. beran, a. (1979b): die mineralogie von ankeriten und sideriten des steirischen erzberges und der radmer.– verh. geol. b.-a., 3, 237–239. beran, a. & thalmann, f. (1977): feinkörnige gebänderte siderite im spateisensteinbergbau radmer-buchegg.– österr. akad. wiss., math.-naturwiss. kl., 4, 57–62. beran, a. & thalmann, f. (1978): der bergbau radmer-buchegg – ein beitrag zur genese alpiner sideritlagerstätten.– tmpm, 25, 287–303. böhlke, j.k. & irwin, j.j. (1992): laser microprobe analyses of cl, br, i, and k in fluid inclusions: implications for sources of salinity in some ancient hydrothermal fluids.– geochimica et cosmochimica acta, 56, 203–255. doi: 10.1016/0016-7037(92)90127-5 bottrell, s.h., yardley, b.w.d. & buckley, f. (1988): a modified crush-leach method for the analysis of fluid inclusion electrolytes.– bull. mineral., 111, 279–290. clar, e. (1956): zur entstehungsfrage der ostalpinen spatmagnesite.– carinthia ii, 60, 22–31. de llarena, j.g. (1953): über die sedimentäre entstehung des ostalpinen magnesits „typus veitsch“.– montan-zeitung, 69, 55–62. friedrich, o. (1959): zur genesis der ostalpinen spatmagnesit-lagerstätten.– radex rundschau, 393–420. frimmel, h. (1988): strontium isotopic evidence for the origin of siderite, ankerite and magnesite mineralizations in the eastern alps.– mineralium deposita, 23, 268–275. doi: 10.1007/bf00206407 hall, w.e. & friedman, i. (1963): composition of fluid inclusions, cave-inrock fluorite district, illinois, and upper mississippi valley zinc-lead district.– economic geology, 58, 886–911. doi: 10.2113/gsecongeo.58.6.886 henjes-kunst, f., prochaska, w., niedermayr, a., sullivan, n. & baxter, e. (2014): sm-nd dating of hydrothermal carbonate formation: an example from the breitenau magnesite deposit (styria, austria).– chem. geol., 387, 184–201. kesler, s.e., martini a.m., appold m.s., walter, l.m., huston t.j. & furman, f.c. (1996): na-cl-br systematics of fluid inclusions from mississippi valley-type deposits, appalachian basin: constraints on solute origin and migration paths.– geochimica et cosmochimica acta, 60/2, 225–233. doi: 10.1016/0016-7037(95)00390-8 koch, m. (1893): mittheilung über einen fundpunkt von untercarbon-fauna in der grauwackenzone der nordalpen.– z. dtsch. geol. ges., 45, 294–298. laube, n., frimmel, h.e. & hoernes, s. (1995): oxygen and carbon isotopic study on the genesis of the steirischer erzberg siderite deposit (austria).– mineral. deposita, 30, 285–293. doi: 10.1007/bf00196364 leitmeier, h. (1917): einige bemerkungen über die entstehung von magnesitund sideritlagerstätten.– mitt. geol. ges. wien, 9, 159–166. leitmeier, h. & siegl, w. (1954): untersuchungen an magnesiten am nordrande der grauwackenzone salzburgs und ihre bedeutung für die entstehung der spatmagnesite der ostalpen.– bhm, 99, 201–208 and 221–235. mccaffrey, m.a., lazar, b. & holland, h.d. (1987): the evaporation path of seawater and coprecipitation of brand k+ with halite.– j. sediment. petrol., 57, 928–937. möller, p. (1989): magnesite – geology, mineralogy, geochemistry, formation of mg-carbonates.– mongraph series on mineral deposits, borntraeger, berlin, 300 p. neubauer, f., handler, r., hermann, s. & paulus, g. (1994): revised lithostratigraphy and structure of the eastern graywacke zone (eastern alps).– mitt. österr. geol. ges., 86, 61–74. neubauer, f. (1994): kontinentkollision in den ostalpen.– geowissenschaften, 12, 136–140. 38 vol. 69/1 niedermayr, g. (1989): die magnesite im perm und skyth des drauzuges.– carinthia ii, 179/99, 391–399. petrascheck, w. (1926): metallogenetische zonen in den ostalpen.– c.r. xiv, congr. geol. intern., madrid 1926, 1243–1253. petrascheck, w. (1932): die magnesite und siderite der alpen. vergleichende lagerstättenstudien.– anz. österr. akad. wiss., math.nat. kl., 141, 195–242. pohl, w. (1986): comparative metallogeny of siderite deposits.– österreichische akademie der wissenschaften, schriftenreihe der erdwissenschaften komm., 8, 271–282. doi: 10.1007/978-3-7091-5822-7_22 pohl, w. & belocky, r. (1994): alpidic metamorphic fluids and metallogenesis in the eastern alps.– mitt. österr. geol. ges., 86, 141–152. pohl, w., amouri, m., kolli, o., scheffer, r. & zachmann, d. (1986): a new genetic model for the north african metasomatic siderite deposits.– mineral. deposita, 21, 228–233. doi: 10.1007/bf00199805 polgári, m., prochaska, w. & beran, a. (2010): alpine carbonate minig sites: aspects of carbonate mineralizations related to the manganese mine of úrkút, hungary, the magnesite deposit of veitsch and the siderite mine «steirischer erzberg», austria.– acta mineralogica petrographica, field guide series, 4, 1–16. prochaska, w. (1991): beispiele für alpidisch-hydrothermale lagerstättenbildung in den ostalpen.– mitt. naturwiss. ver. steiermark, 121, 129–148. prochaska, w. (1997): formation of different siderite provinces during the alpine tectono-metamorphic event in the eastern alps of austria.– in: mineral deposits research and exploration. where do they meet? proceedings of the 4th biennial sga meeting turku 1997, balkema, rotterdam, 1997, 845–848. prochaska, w. (2000): magnesite and talc deposits in austria.– mineralia slovaca, 32, 543–548. prochaska, w. (2001): magnesite mineralizations of the eastern alps and the carpathians.– in: piestrzynski et al. (eds.): mineral deposits at the begining of the 21 st century, swets & zeitlinger publishers lisse, 2001, 1017–1019. prochaska, w. (2012): siderite and magnesite mineralizations in palaeozoic strata of the eastern alps (austria).– field trip guide, 29th ias meeting of sedimentology, schladming, austria, journal of alpine geology, 54, 309–322. prochaska, w., frank, w. & bechtel, a. (1996): pretertiary siderite minerali-zation in the greywacke zone of the eastern alps.– mineralia slovaca-monography, bratislava, 165–174. prochaska, w. & henjes-kunst, f. (2007): the origin of sparry magnesite in the eastern alps (austria): evidence from inclusion fluid and sr-nd isotope chemistry.– in: proceedings of the 9th biennial meeting of the society for geology applied to mineral deposits dublin, iaeg, 2007, 2, 823–826. prochaska, w. & henjes-kunst, f. (2009): genese der siderit-vererzungen der östlichen grauwackenzone aktueller stand der forschung.– arbeitstagung geol. b.-a., 2009, blatt 101 eisenerz, 153–169. redlich, k.a. (1907): die genesis der pinolitmagnesite, siderite und ankerite der ostalpen.– tmpm, 26, 499–505. redlich, k.a. (1909): die typen der magnesitlagerstätten.– z. prakt. geologie, 17, 300–310. rumpf, j. (1873): über krystallisierte magnesite aus den nordöstlichen alpen.– min. petr. mitt., 263–272. schönlaub, h.p. (1982): die grauwackenzone in den eisenerzer alpen (österreich).– jahrb. geol. b.-a., 124, 361–423. schouppe, a. (1854): geognostische bemerkungen über den erzberg bei eisenerz.– jahrb. geol. reichsanstalt, 5, 396–405. schulz, o., vavtar, f. & dieber, k. (1997): die siderit-erzlagerstätte steirischer erzberg: eine geowissenschaftliche studie, mit wirtschaftlicher und geschichtlicher betrachtung.– arch. f. lagerst.forsch. geol. b.-a., 20, 65–178. siegl, w. (1969): entwurf zu einer salinar-sedimentären entstehung der magnesite vom typ entachen (salzbrg).– mineralium deposita, 4, 225–233. spindler, p. (1992): neue untersuchungen zur mineralogie und geochemie der basisbreccie des steirischen erzberges, österreich.– österr. akad. wiss., math.-naturwiss. kl., 1–25. thalmann, f. (1979): zur eisenspatvererzung in der nördlichen grauwackenzone am beispiel des erzberges bei eisenerz und radmer/bucheck.– verh. geol. b.-a., 479–489. thöni, m. (2002): sm-nd isotope systematics in garnet from different lithologies (eastern alps): age results, and an evaluation of potential problems for garnet sm–nd chronometry.– chem. geol., 185, 255–281. doi: 10.1016/ s0009-2541(01)00410-7 tollmann, a. (1977): geologie von österreich. band i die zentralalpen. franz deuticke, wien, 766 p. tufar, w., gieb, j., schmidt, r., möller, p., pohl, w., riedler, h. & olsacher, a. (1989): formation of magnesite in the radenthein type locality (carinthia, austria).– in: möller, p. (ed.): magnesite – geology, mineralogy, geochemistry, formation of mg-carbonates.– monograph series on mineral deposits, berlin, 28, 135–171. vacek, m. (1903): der steirische erzberg.– exk. führer 9. int. geol. kongreß, 27, wien, 27 p. viets, j.g. & leach, d.l. (1990): genetic implications of regional and temporal trends in ore fluid geochemistry of mississippi valley-type deposits in the ozark region.– economic geology, 85, 842–861. doi: 10.2113/gsecongeo.85.4.842 weber, l. (1997): metallogenetische karte von österreich (1: 500.000) und handbuch der lagerstätten der erze, industrieminerale und energierohstoffe österreichs.– arch. lagerst.forsch. geol. b.-a., 19, 1–607. 2016 | 69/3 | 295–305 | 12 figs. | www.geologia-croatica journal of the croatian geological survey and the croatian geological society 1. introduction and geological setting the research area is located in the nw external dinarides of slovenia. this part of the dinarides formed during the cenozoic convergence of the adria and eurasia plates (ustaszewski et al., 2010; handy et al., 2015), which resulted in the formation of different tectonic units in the alps-dinarides-carpathian orogenic system (e.g. schmid et al., 2008). in the n and nw part the study area borders the southern alps, while in the e part, the dinaric and south-alpine units are overlaid by paratethyan sediments of the pannonian basin system (placer, 2008). two main thrust phases are characteristic for this area. the first phase was the la­ test cretaceous to eocene top-to-sw dinaric thrusting on nw-se striking fault planes. based on the biostratigraphic age of flysch sediments in istria, the dinaric thrusting in this area lasted until the late eocene (babić et al., 2007). the second phase is oligocene to early miocene top-to-s south-alpine thrusting on e-w striking fault planes (e.g. placer, 1982; doglioni & bosellini, 1987; castellarin et al., 1992; placer & čar, 1997; placer, 1999; schmid et al., 2004, 2008; van gelder et al., 2015). after the middle-late eocene, the northward directed motion of the adria microplate caused the formation of a few kilometres wide imbricate belt, with steep reverse fault planes in front of the external dinarides along the eastern adriatic coast (placer et al., 2001, 2010; tari 2002; vrabec & fodor, 2006). according to map-view reconstructions, the northward motion of the adria microplate in the neogene resulted in appro palaeostress and kinematic evolution of the orogen-parallel nw-se striking faults in the nw external dinarides of slovenia unraveled by mesoscale fault-slip data analysis lea žibret1,2 and marko vrabec1 1 university of ljubljana, faculty of natural sciences and engineering, department of geology, privoz 11, si-1000 ljubljana, slovenia 2 research and development in the field of natural sciences, černetova ulica 3a, si-1000 ljubljana, slovenia; (corresponding author: zibret.lea@gmail.com) doi: 10.4154/gc.2016.30 abstract the late eocene to recent dynamics of the nw external dinarides in slovenia are described. the study is focused on the orogen-parallel nw-se striking family of faults, which represent the main source of seismic hazard in the nw external dinarides today. approximately 1700 faultslip datasets were collected at 70 locations and used for palaeostress analysis. structural relationships observed in the field, allowed the construction of a relative chronology between the documented fault and shear joint sets, facilitating the reconstruction of their kinematic evolution and the chronology of palaeostress phases. four post-palaeocene stress tensor groups are documented corresponding to four distinct tectonic phases. the first phase is marked by ne-sw directed compression attributed to late eocene top-to-sw thrusting of external dinarides. the second phase is characterized by ne-sw oriented tension, documented by normal slips recorded on nw-se striking faults. this tension is interpreted as an expression of the early to middle miocene back-arc extension in the pannonian basin system that also affected the studied part of the external dinarides. the third phase is manifested by approximately e-w oriented compression with approximately n-s oriented tension in a strike-slip stress regime, causing sinistral reactivation of nw-se trending faults. geodynamically, this phase can be correlated with the late miocene short pulse of e-w directed compression, documented in parts of the pannonian basin system. the youngest phase is characterized by approximately n-s oriented compression and approximately e-w oriented tension in a strike-slip stress regime, which caused dextral reactivation of nw-se striking faults. this phase correlates with the recent inversive/transpressive phase, well-established from seismological data. ximately 190 km total n-s shortening (ustaszewski et al., 2008). in the kinematic reconstruction of placer (1981, 1998) the total sw-ne directed shortening across the slovenian external dinarides is around 50 km. in the nw external dinarides the major structures which accommodate recent crustal stresses are steep to subvertical nw­se striking faults with a significant linear topographic expression, evident on a regional scale. they cut and displace dinaric and south-alpine thrust-related structures and are therefore commonly interpreted as reflecting the final stage of the tectonic evolution of the dinarides (picha, 2002; vrabec & fodor, 2006). their neotectonic importance is supported by earthquake focal mechanisms, which predominantly illustrate a strike-slip stress regime with a nnw-sse directed s1 axis (poljak et al., 2000; kastelic et al., 2008; herak et al., 2009; kastelic et al., 2013). recent nnw-sse oriented contraction is also evident from regional gps data analysis (weber et al., 2006; weber et al., 2010), analysis of geomorphic markers (jamšek rupnik et al., 2014; moulin et al., 2014; žibret & žibret, 2014), and geophysical investigations (gosar, 1998; bavec et al., 2012; zajc et al., 2015). spatial analysis of earthquake events demonstrates complex interactions in the fault zones, likely controlled by their complex geometry originating in their polyphase tectonic evolution (e.g. kastelic et al., 2008). to date, only a few studies have investigated late-orogenic structural and geodynamic evolution of the dinarides, mostly in the central internal dinarides of croatia, bosnia and herzegovina, and albania article history: manuscript received february 27, 2016 revised manuscript accepted september 16, 2016 available online october 07, 2016 keywords: fault-slip analysis, palaeostress reconstruction, tectonic phases, nw external dinarides g eo lo gi a c ro at ic a geologia croatica 69/3296 (pamić et al., 1998; tomljenović & csontos, 2001; picha, 2002; tari, 2002; ilić & neubauer, 2005, tom­ ljenović et al., 2008; ustaszewski et al., 2010), while there is no integrated study concerning the neogene tectonic evolution of the nw external dinarides of slovenia. the aim of this study is to reconstruct the palaeostress evolution in the nw external dinarides and to examine the kinematic history of the nw-se striking orogen parallel faults. in the central part of the dinarides, the oldest cenozoic tectonic phase is characterized by generally ne-sw to e-w oriented compression, related to palaeogene thrusting of the dinarides towards the w­sw onto an undeformed adria microplate (ilić & neubauer, 2005). there, the oligocene to early miocene transition was characterized by post collisional volcanism, probably partly controlled by e-w oriented tension, since the magmatic processes during the aforementioned period were much more complex (mladenović et al., 2015). the early and middle miocene is marked by ne-sw oriented tension, perpendicular to the strike of the dinaric orogen. according to interpretations by tomljenović & csontos (2001), ilić & neubauer (2005) and ustaszewski et al. (2010) the early and middle miocene orogen-perpendicular tensional phase was related to syn-rift extension in the pannonian basin system. in the central part of the dinarides of eastern bosnia the middle miocene tensional phase becomes orogen­parallel (ilić & neubauer, 2005). between the late miocene and pliocene, subduction in the carpathians terminated (horváth & cloetingh, 1996), causing a regional change in the stress regime. in the dinarides this episode is reflected by generally n­s oriented compression in the strike­slip tectonic regime (ilić & neubauer, 2005, mladenović et al., 2015). the ongoing north directed push of the adria microplate and termination of subduction in the carpathian arc, which facilitated free movements of continental blocks towards the east during the late oligocene – miocene, induced a counter-clockwise rotation of the adria microplate during the pliocene and quaternary (márton et al., 2002). today this is evident in decreased rates of slip along active faults from the se to the nw external dinarides (weber et al., 2010; kastelic & carafa, 2012). 2. data collection and processing approximately 1700 fault­slip measurements acquired at 70 localities in the nw external dinarides were analysed. fault­slip data was collected at 51 localities in mesozoic sediments derived from the dinaric carbonate platform and in miocene sediments of the central paratethyan area of slovenia. measurements were supplemented by data from gregorič (2005) collected at 19 localities in palaeogene sediments of dinaric foreland basins (fig. 1). analysis included orientation of fault­plane and fault­slip lineation with the sense of slip determined using different types of kinematic indicators (e.g. petit, 1987; doblas, 1998; sperner & zweigel, 2010). stress tensors were calculated by inversion of measured fault-slip data. these methods are based on the assumption that the direction of movement and the shear stress along the fault are parallel (wallace, 1951; bott, 1959). the mean stress tensor was determined, knowing the orientations and senses of slip on numerous faults, assuming that each observed fault-slip (indicated by a slickenside lineation) has the direction and sense of shear stress that corresponds to a single common stress tensor (angelier, 1994). a fault­slip dataset may involve errors caused by dispersion in local stress patterns as well as fault segfigure 1. fault-slip data measurement locations in the nw external dinarides of slovenia. traces of major thrusts and strike-slip faults are compiled from vrabec & fodor (2006), kastelic et al. (2008), tomljenović et al. (2008) and busetti et al. (2010). stratigraphic units are simplified after budkovič et al. (2003). g eologia c roatica žibret and vrabec: palaeostress and kinematic evolution of the orogen-parallel nw-se striking faults in the nw external dinarides of slovenia ... 297 ment interplay and for other reasons. therefore, the aim is to look for the best fit between measured fault­slip data and a theoretical common stress tensor. the misfit between these is described by the angle between the actual slip and the theoretical shear stress on a fault plane (angelier, 1994), the so called „misfit criteria”. stress tensors are generally described by six independent variables in matrix form (equation (1); angelier, 1994): a d e d b f e f c (1) in the co­ordinate system defined by the principal stress axes (equation (2); angelier, 1994): 1 0 0 0 2 0 0 0 3 s s s (2) three components of the stress tensor (eigenvalues) describe the orientation of the principal stress axes s1, s2, s3, where: s1 (maximum stress), s2 (intermediate stress) and s3 (minimum stress), and where s1 ³ s2 ³ s3. a fourth value is the ratio between the eigenvalues of a stress tensor (bishop ś (1966) stress parameter) which describes the relative magnitude of the eigenvalues: f = (s2 – s3) / (s1 – s3). the last two variables describe the frictional and brittle characteristics of a rock mass (angelier, 1994). however, it is not possible to estimate frictional and brittle characteristics directly from fault-slip data. therefore only reduced stress tensors with four variables (eigenvalues and ϕ) can be determined. for palaeostress analysis the gauss method (žalohar & vrabec, 2007) and the multiple­slip method (žalohar & vrabec, 2008) were used. in the gauss method, the distribution of the misfit angle between the measured direction of slip and shear stress is approximated with the gaussian distribution and an optimal stress tensor is determined by maximizing the gaussian function (žalohar & vrabec, 2007). the multiple-slip method combines kinematic and dynamic approaches (žalohar & vrabec, 2008). a fault plane is activated only when the applied shear stress exceeds the frictional shear strength. in both methods mechanical compatibility of solutions for individual stress tensors is controlled by the three-dimensional mohr diagram. since most of the study region comprises highly deformed rocks and the orientation of the sedimentary beds changes very rapidly (in some cases every few metres), palaeostress inversion has been undertaken separately for each measurement location (outcrop). where the orientation of sedimentary beds changes within the individual outcrop, the location was divided into an appropriate number of sub-locations with constant bed orientation, and each sub-location was then analysed separately. because the measured fault-slip data were highly heterogeneous, each dataset (each locality/sub-locality) has been manually separated into homogeneous data subsets using a maximum misfit criteria of 30°. in strike-slip fault zones internal block rotations are common (e.g. nozaem et al., 2013), and regional block rotations were also inferred in the study area (vrabec & fodor, 2006). therefore some allowance was made in the analyses for variations in the orientation of principal stress axes, and stress fields close in axis orientation were assumed to have originated in the same general regional stress fields. a detailed description of the data separation procedure and of calculated palaeostress parameters for individual fault subsets is documented in the first author̀ s phd thesis (žibret, 2015). regional relevance of the determined stress fields is supported by their consistent occurrence throughout the study area. a first­order timing constraint for palaeostress phases is given by the stratigraphic ages of rocks in which the respective fault-slip data occur. however, this only gives a very rough time bracket since the majority of investigated rocks are mesozoic in age. a relative chronology of documented palaeostress phases was derived from the following field criteria: – overprinting relationships between different families of fault striations on the same fault plane, – cross­cutting relationships between outcrop­scale and regional-scale faults, and – ductile/brittle character of deformation, assuming ductile phases preceded brittle deformations. 3. regional palaeostress phases 3.1. documented palaeostress tensors ne-sw compression (phase 1) the first phase (phase 1, fig. 2) is characterized by a ne­sw directed maximum palaeostress axis s1, and approximately vertical s3 axis. this phase is manifested on reverse nw-se striking faults and thrusts, which dip from 30° to 75° towards the sw and ne. it was reconstructed by fault-slip data recorded at only about 15 % of the measured sites and thus it seems that they are not well preserved, probably because of overprinting by younger movements. nevertheless, in some places mesoscopic-scale duplex structures indicating ne-sw directed compression have been observed. figure 2. a) examples of fault-slip data and derived stress tensors for phase 1. b) regional stress field of phase 1 (in present-day reference frame, not accounting for any vertical-axis rotations). g eo lo gi a c ro at ic a geologia croatica 69/3298 figure 3. a) examples of fault-slip data and derived stress tensors for phase 2. b) regional stress field of phase 2 (in present-day reference frame, not accounting for any vertical-axis rotations). ne-sw tension (phase 2) the second phase (phase 2, fig. 3) is marked by a ne­sw oriented minimum palaeostress axis σ3 and an approximately vertical σ1 axis. fault­slip data that document this phase are very ubiqu­ itous. at almost 40 % of the measured locations, normal to oblique-normal slips on steep to moderately dipping fault planes (dipping 60° to 85° towards ne or sw) have been recorded indicating a ne-sw directed tensional phase. structures originating from this palaeostress phase are noticeably present in both mesoscopic and map scales of observa-of observation. nw-se striking faults with a normal sense of slip, dipping around 60° towards the ne or sw, often exhibiting conjugate geometry typical for neo-formed normal faults, were observed in many outcrops. at the map scale, normal offsets on nw-se striking faults have also been recorded in several places. one example is presented in figure 4., where consistent dipping of beds towards the faults suggests that normal faulting was accompanied by domino-style rotations of their hanging wall blocks. e-w compression in a strike-slip regime (phase 3) the third phase (phase 3, fig. 5) is characterized by a palaeostress tensor with approximately e­w trending σ1 and n-s oriented σ3 axes in the strike-slip stress regime. this phase is typically represented by sinistral reactivations of nw-se striking fault planes. it was recognized at approximately 20% of sites and is apparently a rather weak phase, since (except for collected fault-slip data) neither outcrop-scale nor map-scale structures were discovered that could be reliably related to this phase. n-s compression in strike-slip regime (phase 4) the fourth phase (phase 4, fig. 6) is characterised by an approximately n-s oriented maximum palaeostress axis s1 with approximately e-w trending s3 axis in the strike-slip stress regime. besides, it is presumed to be contemporaneous with nnw-sse oriented maximum palaeostress axis s1 in compressional stress regime. locally, the trend of s1 is nne­ssw (fig. 6b) and close to regional strike-slip faults, which could be explained as local vertical-axis block rotations. this stress-strain relationship is very common throughout the study area and was documented at more than 70% of the analysed locations. the main manifestation of this phase is a dextral reactivation of nw-se-trending fault planes. 3.2. relative chronology of documented palaeostress phases the first­order constraint on the time­span of documented pa­ laeostress phases is given by the biostratigraphic age of sedimentary rocks in which the data were acquired. most of the studied rocks in the nw external dinarides in slovenia (fig. 1) originated from the mesozoic-palaeogene adriatic carbonate platform (turnšek et al., 1982; črne & goričan, 2008; jež et al., 2011), overlain in the w and sw part by a roughly nw-se-trending belt of palaeocene to eocene dinaric foreland flysch basin sediments (debeljak et al., 2002; otoničar, 2007; drobne et al., 2011; pavlovec, 2012). besides, in the ne part of the study area, the youngest analysed sediments belong to central figure 4. examples of normal faulting in ne-sw tension (phase 2). a) outcropscale normal faults in triassic dolomite at location 6 (x = 72804, y = 475508). b) map-scale normal faults south of ljubljana (for location see in fig. 1), indicating domino-style rotations of hanging wall blocks (adapted from buser et al., 1963). g eologia c roatica žibret and vrabec: palaeostress and kinematic evolution of the orogen-parallel nw-se striking faults in the nw external dinarides of slovenia ... 299 paratethyan formations dating from the palaeocene to late middle miocene (fodor et al., 1998; jelen & rifelj, 2002; fodor et al., 2002; mikuž et al., 2012; bartol et al., 2014). as previously described in section 2, the relative chronology of palaeostress phases (phase 1 – phase 4) is based on direct field observations of fault-slip data, their cross cutting relationships and the deformation style. each of the three criteria is described below with representative examples. 3.3. the overprinting relationship of different generations of fault striations on the same fault plane at location 1 (fig. 1) multiple generations of fault striations were documented on a single steep sw­dipping fault plane. on this plane slickenlines attributed to phase 3 crosscut the dip-slip normal ones attributed to phase 2 (fig. 7 a). this structural relationship suggests that ne-sw oriented tension (phase 2) is older than e-w oriented compression in the strike-slip palaeofigure 5. a) examples of fault-slip data and derived stress tensors for phase 3. b) regional stress field of phase 3 (in present-day reference frame, not accounting for any vertical-axis rotations). figure 6. a) examples of fault-slip data and derived stress tensors for phase 4. b) regional stress field of phase 4 (in present-day reference frame, not accounting for any vertical-axis rotations). figure 7. examples of slickenlines overprinting criteria described in the text documented at location 1 as indicated in fig. 1 (location 1; x = 90946, y = 453387). g eo lo gi a c ro at ic a geologia croatica 69/3300 stress regime (phase 3). besides, on the same fault plane, slickenlines that indicate dextral slip overprint the dip-slip normal ones (fig. 7 b), which again clearly indicates that ne­sw oriented tension (phase 2) predates strike-slip reactivation of this fault, this time however, in a nnw-sse oriented compression in the strike­slip palaeostress regime attributed to phase 4. whereas the overprinting cri teria of striae on fault planes are occasionally strongly influenced by the viewpoint of the observer and are therefore rarely unambiguous (sperner & zweigel, 2010), the calcite accretionary steps that have grown inside sub-vertical grooves on this fault plane clearly indicate that the dextral sense of slip attributed to phase 4 postdates the normal­slip episode of phase 2 (fig. 7 c). 3.4. cross-cutting relationships between a regional thrust plane and normal faults in central slovenia the outcropping plane of the regional-scale hrušica thrust (outcrop location p on fig. 1 – in the central part of the idrija fault zone south from the main fault trace, marked by red cross; also shown on fig. 8) belonging to the dinaric thrust system (placer, 1981) was examined. here, the principal thrust plane, dipping 10° towards the nne to ne (fig. 8 a, c), is offset by small-scale ne-dipping normal faults, which exhibit dip-slip striae and calcite steps indicating normal slip (fig 8 b, d). again, this relationship suggests that the ne-sw tension (phase 2) postdates dinaric thrusting (phase 1). the ductile/brittle character of deformation the bevk tectonic window mapped at location of x = 95048, y = 422800 exposes highly­deformed eocene flysch deposits below the trnovo thrust (outcrop location 40 on fig. 1, also shown on fig. 9). this is the highest major thrust of the dinaric thrust system of slovenia (placer, 1981; mlakar & čar, 2010). an approximately ne-sw-striking fault, which delimits the window to the east, rotated this structure so that here the trnovo thrust plane dips slightly to the s(sw) instead of to the ne, which is typical elsewhere in the surrounding area. eocene mudstones are strongly foliated (fig. 9 a), with foliation intensity increasing towards the thrust contact. micro folds and shear-bands in the folia tion indicate top­to­the­s(se) thrusting (fig. 9 b). this foliation was cut under (semi)brittle conditions by wswene-striking shear zone with a clear sinistral sense of displacement, which pro duced decimetre-scale drag folds in the foliation and veins (fig. 9 c). the shear zone was formed in ne­sw­oriented compression presumably during or immediately following the dinaric thrusting, which we attributed to the palaeostress phase 1. moreover, this shear zone is cut by perpendicular dipslip-normal faults with cm-scale displacements, which originated in ne­sw­directed ten sion attributed to phase 2 (fig. 9 d). finally, brittle kinematic indicators on wsw­ene­striking fault planes suggest late n(nne)-s(ssw) directed compression with perpendicular tension in the strike-slip regime attributed to phase 4. based on the described examples and criteria used for the relative chronology of the documented fault-slip datasets, we distinguished five groups of faults attributed to four palaeostress phases shown in figure 10. the results of palaeostress calculations based on fault-slip data obtained in rocks of different ages are summarized in figure 11. 4. geodynamic interpretation the palaeostress phase 1, which is characterized by ne-sw directed compression, is documented by slickenside lineation and indicators for the sense of slip that are scarcely and poorly preserved and documented in the study area. moreover, the overprinting and cross-cutting relationships of faults attributed to this phase with younger faults indicate that phase 1 is the oldest documented phase in the study area. as this phase was documented in eocene flysch deposits, it is certainly of eocene or post eocene age. the same stress calculation was obtained from fault-slip data collected in neogene rocks (fig. 11), but only at four distinct locations with a wide span of calculated compression orientation. since no mesoscale structures that could be related to ne-sw oriented compression were observed in neogene rocks, these results are considered to be unreliable. therefore, we constrained the age of palaeostress phase 1 as eocene or post-eocene to preneogene. in a regional tectonic framework it fits well with the middle-late eocene thrusting of the external dinarides towards the sw onto the undeformed adria microplate (e.g. ilić & neubauer, 2005; schmid et al., 2008; placer et al., 2010; van gelder et al., 2015; fig. 12). phase 2 is characterized by ne-sw oriented tension in the extensional tectonic regime (fig. 12). based on the relative chronology of slicken-side lineation and kinematic indicators, phase 2 is older than phases 3 and 4. with the assumption that phase 1 is the oldest palaeostress phase of post-eocene to pre-neogene age, the activity of phase 2 can be presumed to have occurred during the neogene. based on the presumed time of activity and calculated ne-sw directed tension perpendicular to the strike of the dinaric orogen, phase 2 correlates well with the early and figure 8. mesoscopic scale cross-cutting relationships where the thrust plane of the regional-scale hrušica thrust is offset by small-scale normal faults (for out(for outcrop location see fig. 1; x = 76192, y = 441388). see in text for details. g eologia c roatica žibret and vrabec: palaeostress and kinematic evolution of the orogen-parallel nw-se striking faults in the nw external dinarides of slovenia ... 301 figure 9. ductile/brittle style of deformation (for location see fig. 1). a) foliated eocene mudstone (dotted line on stereogram) below the thrust plane (continuous line on stereogram). b) micro folds (indicated in red) in foliation. c) drag folds in foliation and veins (dotted line on stereogram) along sinistral wsw-ene-striking shear zone (continuous line on stereogram). d) the same shear zone cut by perpendicular dip-slip-normal faults (continuous line on stereogram). figure 10. relative chronology of documented palaeostress phases and description of related fault-slip datasets. g eo lo gi a c ro at ic a geologia croatica 69/3302 middle miocene ne-sw oriented tension previously document ed in the sw margin of the pannonian basin (e.g. tomljenović & csontos, 2001), in the internal dinarides (e.g. ilić & neu­), in the internal dinarides (e.g. ilić & neubauer, 2005) and in the internal dinarides – pannonian basin transitional area (ustaszewski et al., 2010). all the aforemenall the aforementioned studies assume that the lower and middle miocene orogen perpendicular extensional phase is geodynamically related to the back arc extension in the pannonian basin system. figure 11. comparison of determined palaeostress phases by age of rocks in which the fault-slip data was obtained. each palaeostress tensor is represented by σ1 orientation (red axis on stereograms) and σ3 orientation (blue axis on stereograms). in the lower part of the figure, mean palaeostress axis orientation and corresponding mohr circle is shown for each phase. g eologia c roatica žibret and vrabec: palaeostress and kinematic evolution of the orogen-parallel nw-se striking faults in the nw external dinarides of slovenia ... 303 phase 3 is marked by approximately e-w oriented compression with approximately n-s oriented tension in a strike-slip stress regime (fig. 12). the relative chronology of slicken-side lineation and kinematic indicators show that phase 3 is younger than phase 2 and precedes phase 4 which was presumably active since the pliocene (see below). therefore, the remaining time bracket for phase 3 activity is the late miocene. in the dinaricalpine-carpathian-pannonian region, the late miocene e-w oriented compression, which inverted previously sinistral nesw striking faults (formed during lateral extrusion in early and middle miocene) into late miocene reverse faults was first described in the vienna basin by peresson & decker (1997). later, corresponding faults were detected in different parts of the pannonian basin system (e.g. fodor et al., 1999). according to pe resson & decker (1997) this late miocene change of pa laeo stress reflects the cessation of subduction in the eastern carpathians which in turn disabled further eastward extrusion in the eastern alps. therefore, the final pulse of subduction in the eastern carpathians may have established an e-w directed compressive regional stress field, that could have been transmitted through the crust of the pannonian basin into the eastern alps (peresson & decker, 1997), and possibly even further south-westwards into the nw external dinarides, thus causing inversion of the steep nw-se striking normal faults in the nw external dinarides into faults with a sinistral sense of slip (fig. 12). palaeostress tensors attributed to phase 4 that is characterized by approximately n-s oriented compression and approximately e-w oriented tension in a strike-slip stress regime is the most ubiquitous phase in the study area, coinciding with the recent stress tensors of the wider south alpine-dinarides transitio nal area (e.g. caporali et al., 2013). thus, it is probably representative of the well known inversive/transpressive regional phase in the nw external dinarides and the sw margin of the pannonian basin (e.g. tomljenović & csontos, 2001; ustaszewski et al., 2010; fig. 12). in this area, nw-se striking steep to subvertical dextral faults are known as active during the pliocene and quaternary time (e.g. kastelic et al., 2008; herak et al., 2009; moulin et al., 2014), and their origin is explained by ccw rotation of the adria microplate (to mlje nović & csontos, 2001; márton et al., 2002; vrabec & fodor, 2006; weber et al., 2010). figure 12. geodynamic interpretation of the documented tectonic phases in the nw external dinarides of slovenia. g eo lo gi a c ro at ic a geologia croatica 69/3304 bishop, a.w. (1966): the strength of soils as engineering materials.– geotechnique, 16, 91–130. bott, m.h.p. (1959): the mechanisms of oblique slip faulting.– geol. mag., 96, 109–117. budkovič, t., šajn, r. & gosar, m. (2003): environmental impact of active and abandoned mines and metal smelters in slovenia.– geologija, 46/1, 135–140. doi: 10.5474/geologija.2003.014 buser, s., ferjančič, l., grad, d., kerčmar­turnšek, d., mencej, s., orehek, s., pavlovec, r., pleničar., m., prestor, l., rijavec, l. & šribar, l. (1963): osnovna geološka karta sfrj 1 : 100 000, list postojna.– sav. geol. zavod, beograd. busetti, m., volpi, v., nicolich, r., barison, e., romeo, r., baradello, l., brancatelli, g., giustiniani, m., marchi, m., zanolla, c., wardell, n., nieto, d. & ramella, r. (2010): dinaric tectonic features in the gulf of trieste (northern adriatic sea).– b. geofis. teor. appl., 51/2–3, 117–128. caporali, a., neubauer, f., ostini, l., stangl, g. & zuliani, d. (2013): modeling surface gps velocities in the southern and eastern alps by finite dislocations at crustal depths.– tectonophysics, 590, 136–150. doi: 10.1016/j.tec­10.1016/j.tecto.2013.01.016 castellarin, a., cantelli, l., fesce, a.m., mercier, j.l., picotti, v., pini, g.a., prosser, g. & selli, l. (1992): alpine compressional tectonics in the southern alps. relationships with the n-apennines.– annales tectonicae, 4, 62–94. črne, a.e. & goričan, š. (2008): the dinaric carbonate platform margin in the early jurassic: a comparison between succession in slovenia and montenegro.– boll. soc. geol. ital., 127/2, 389–405. debeljak, i., košir, a., buffetaut, e. & otoničar, b. (2002): the late cteraceous dinosaurs and crocodiles of kozina (sw slovenia): a preliminary study.– memorie – società geologica italiana, 57, 193–201. doblas, m. (1998): slickenside kinematic indicators.– tectonophysics, 295, 187–197. doglioni, c. & bosellini, a. (1987): eoalpine and mesoalpine tectonics in the southern alps.– int. j. earth sci., 76, 735–754. drobne, k., ćosović, v., moro, a. & bucković, d. (2011): the role of the paleogene adriatic carbonate platform in the spatial distribution of alveolinids.– turk. j. earth sci., 20, 721–751. doi: 10.3906/yer­0911­76 fodor, l., jelen, b., márton, e., skaberne, d., čar, j. & vrabec, m. (1998): miocene­pliocene tectonic evolution of the slovenian periadriatic fault: implications for alpine­carpathian extrusion models.– tectonics, 17, 690–709. fodor, l., csontos, l., bada, g., györfi, i. & benkovics, l. (1999): tertiary tectonic evolution of the pannonian basin system and neighbouring orogens: a new synthesis of palaeostress data.– in: durand, b., jolivet, l., horváth, f. & séranne, m. (eds.): the mediterranean basins: tertiary extension within the alpine orogen. geological society, london, special publications, 156, 295–334. fodor, l., jelen, b., márton, e., rifelj, h., kraljić, m., kevrić, r., marton, p., koroknai, b. & baldi­beke, m. (2002): miocene to quaternary deformation, stratigraphy and paleogeography in northeastern slovenia and southwestern hungary.– geologija, 45, 103–114. doi:10.5474/geologija.2002.009 van gelder, i., matenco, l., willingshofer, e., tomljenović, b., andriessen, p.a.m., ducea, m.n., beniest, a. & gruić, a. (2015): the tectonic evolution of a critical segment of the dinarides­alps connection: kinematic and geochronological inferences from the medvednica mountains, ne croatia.– tectonics, 34, 1952–1978. doi: 10.1002/2015tc003937 gosar, a. (1998): seismic reflection surveys of the krško basin structure: implications for earthquake hazard at the krško nuclear power plant, southeast slovenia.– j. appl. geophys., 39, 131–153. gregorič, a. (2005): analiza razvoja paleonapetosti v dinarskem narivnem sistemu zahodne slovenije (okolica nove gorice).– unpubl. diploma thesis, faculty of natural sciences and engineering, university of ljubljana, 84 p. handy, r.m., ustaszewski, k. & kissling, e. (2015): reconstructing the alps­ carpathians-dinarides as a key to understanding switches in subduction polarity, slab gaps and surface motion.– int. j. earth sci., 104, 1–26. doi: 10.1007/s00531­ 014­1060­3 herak, d., herak., m. & tomljenović, b. (2009): seismicity and earthquake focal mechanisms in north­western croatia.– tectonophysics, 465, 121–220. doi: 10.1016/j.tecto.2008.12.005 horváth, f. & royden, l. (1981): mechanism for the formation of the intra­carpathian basins: a review.– earth evolution science, 3, 307–316. horváth, f. & cloetingh, s. (1996): stress­induced late­stage subsidence ano­ malies in the pannonian basin.– tectonophysics, 266, 287–300. ilić, a. & neubauer, f. (2005): tertiary to recent oblique convergence and wrenching of the central dinarides: constraints from palaeostress study.– tectonophy sics, 410, 465–484. doi: 10.1016/j.tecto.2005.02.019 jamšek rupnik, p., benedetti, l., preusser, f., bavec, m. & vrabec, m. (2014): geomorphic evidence of recent activity along the vodice thrust fault 5. conclusions according to the results of palaeostress analysis it was possible to separate (at least) four different stress tensor groups that have affected the nw external dinarides in slovenia from the late eocene to the recent. during the neogene, the majority of the stress was accumulated and released along generally nw-se striking faults (and to those fault related structures). the current study demonstrates that these faults have a complex polyphase kinematic history. the oldest palaeostress tensor group (phase 1) is characterized by ne-sw directed compression, manifested by reverse slips along generally nw-se striking faults. regionally this phase can be correlated with the main eocene top-to-the-sw thrusting phase of the external dinarides. the second palaeostress tensor group (phase 2) is marked by ne-sw directed tension. this phase normally inverted older reverse and thrust faults connected to dinaric thrusting (phase 1). normal inversion of nw-se striking earlier reverse faults is obviously an important tectonic phase, evident not only in outcrop but also in map-scale structures. regionally this phase coincides with back arc, syn-rift extension in the pannonian basin system. the time bracket for this phase is lower to middle miocene. the third palaeostress tensor group (phase 3) is characterised by approximately e-w oriented compression with approximately n-s oriented tension in the strike­slip stress regime. generally, e­w directed compression probably induced sinistral inversion of earlier nw-se striking normal faults. regionally this phase can be correlated with the late miocene short pulse of e-w directed compression, documented in the vienna basin and also in different parts of the pannonian basin system. the youngest palaeostress tensor group (phase 4) is characterized by approximately n­s oriented compression and perpendicular approximately e-w oriented tension in the strike-slip stress regime, but also by generally n-s oriented compression in a pure compressional stress regime. this phase is partly accommodated by generally e-w striking reverse faults that overprinted older structures and partly by dextral inversion of previously formed faults with dinaric strike. regionally, this phase correlates well with the recent inversive/transpressive tectonic phase in the wider south alpine – nw dinarides area. acknowledgement this research was funded by the slovenian research agency (young researcher grant­contract number 1000­09­310070 and program group p1­0195 geochemical and structural processes). authors are grateful to asta gregorič for fault­slip data from her diploma thesis. we would like to thank to bruno tom lje­ no vić for editorial handling and his careful review that signi­ ficantly improved the manuscript. we would also like to thank to another anonymous reviewer for many constructive comments. references angelier, j. (1994): fault slip analysis and palaeostress reconstruction.– in: hancock, p.l. (eds.): continental deformation. pergamon press, oxford, 53–99. babić, l., hernitz kučenjak, m., ćorić, s. & zupanič j. (2007): the middle eocene age of the supposed late oligocene sediments in the flysch of the pazin basin (istria, outer dinarides).– natura croatica, 16, 83–103. bartol, m., mikuž, v. & horvat, a. (2014): palaeontological evidence of communication between the central paratethys and the mediterranean in the late badenian/early serravalian.– palaeogeogr. palaeocl., 394, 144–157. doi: 10.1016/j. palaeo.2013.12.009 bavec, m., car, m., stopar, r., jamšek rupnik, p. & gosar, a. (2012): geo physical evidence of recent activity of the idrija fault, kanomlja, nw slovenia.– materials and geoenvironment, 59, 247–256. g eologia c roatica žibret and vrabec: palaeostress and kinematic evolution of the orogen-parallel nw-se striking faults in the nw external dinarides of slovenia ... 305 in the ljubljana basin (slovenia) a preliminary study.– ann. geophys. italy, 56, 1–8. doi: 10.4401/ag­6252 jelen, b. & rifelj, h. (2002): stratigraphic structure of the b1 tertiary tectonostratigraphic unit in eastern slovenia.– geologija, 45/1, 115–138. jež, j., otoničar, b., fuček, l. & ogorelec, b. (2011): late cretaceous se­ dimentary evolution of a northern sector of the adriatic carbonate platform (matarsko podolje, sw slovenia).– facies, 57/3, 447–468. doi: 10.1007/s10347­010­ 0249­6 kastelic, v., vrabec, m., cunningham, d. & gosar, a. (2008): neo­alpine structural evolution and present­day tectonic activity of the eastern southern alps: the case of the ravne fault, nw slovenia.– j. struct. geol., 30, 963–975. doi: 10.1016/j.jsg.2008.03.009 kastelic, v. & carafa, m. (2012): fault slip rates for active exterlam dinarides thrust­and­fold belt.– tectonics, 31, 1–18. doi: 10.1029/2011tc003022 kastelic, v., vannoli, p., burrato, p., fracassi, u., tiberti, m.m. & valensise, g. (2013): seismogenic sources in the adriatic domain.– mar. petrol. geol., 42, 191–213. doi: 10.1016/j.marpetgeo.2012.08.002 márton, e., fodor, l., jelen, b., márton, p., rifelj, h. & kevrić, r. (2002): miocene to quaternary deformation in ne slovenia: complex paleomagnetic and structural study.– j. geodyn., 34, 627–651. mikuž, v., bartol, m. & ulaga, š. (2012): the brachiopod lingula from the middle miocene – badenian beds of slovenia.– geologija, 55/2, 271–274. doi: 10.5474/geologija.2012.017 mladenović, a., trivić, b. & cvetković, v. (2015): how tectonics controlled post­collisional magmatism within the dinarides: inferences based on study of tectono­magmatic events in the kopaonik mts. (southern serbia).– tectonophy­ sics, 646, 36–49. doi: 10.1016/j.tecto.2015.02.001 mlakar, i. & čar, j. (2010): geological map of the idrija – cerkljansko hills between stropnik and rovte 1 : 25.000.– geological survey of slovenia, ljubljana. moulin, a., benedetti, l., gosar, a., jamšek rupnik, p., rizza, m., bourlès, d. & ritz, j.f. (2014): determining the present­day kinematics of the idrija fault (slovenia) from airborne lidar topography.– tectonophysics, 628, 188–205. doi: 10.1016/j.tecto.2014.04.043 nozaem, r., mohajjel, m., rossetti, f., della seta, m., vignaroli, g., yassaghi, a., salvini, f. & eliassi, m. (2013): post­neogene right­lateral strike-slip tectonics at the north-western edge of the lut block (kuh-e-sarhangi fault), central iran.– tectonophysics, 589, 220–233. doi: 10.1016/j.tecto.2013.01.001 otoničar, b. (2007): upper cretaceous to paleogene forbulge unconformity associated with foreland basin evolution (kras, matarsko podolje and istria; sw slovenia and nw croatia).– acta carsol., 36, 101–120. pamić, j., gušić, i. & jelaska, v. (1998): geodynamic evolution of the central dinarides.– tectonophysics, 297, 251–268. doi: 10.1016/s0040­1951(98)00171­1 pamić, j., tomljenović, b. & balen, d. (2002): geodynamic and petrogenetic evolution of alpine ophiolites from the central and nw dinarides: an overview.– lithos, 65, 113–142. doi: 10.1016/s0024­4937(02)00162­7 pavlovec, r. (2012): numulitine iz zunanjih dinaridov.– folia biologica et geolo­ gica, 53/3, 85–109. peresson, h. & decker, k. (1997): far­field effects of late miocene subduction in the eastern carpathians: e­w compression and inversion of structures in the alpine­carpathian­pannonian region.– tectonics, 16/1, 38–56. petit, j.p. (1987): criteria for the sense of movement on fault surfaces in brittle rocks.– j. struct. geol., 9, 597–608. picha, f.j. (2002): late orogenic strike­slip faulting and escape tectonics in frontal dinarides­hellenides, croatia, yugoslavia, albania, and greece.– aapg bull., 86/9, 1659–1671. placer, l. (1981): geologic structure of southwestern slovenia.– geologija, 24, 27–60. placer, l. (1982): structural history of the idrija mercury deposit.– geologija, 25, 7–94. placer, l. & čar, j. (1997): structure of mt. blegoš between the inner and outer dinarides.– geologija, 40, 305–323. doi: 10.5474/geologija.1997.016 placer, l. (1998): contribution to macrotectonic subdivision of the border region between southern alps and external dinarides.– geologija, 41, 223–255. doi: 10.5474/geologija.1998.013 placer, l., živčić, m. & vrabec, m. (2001): recent deformation and seismic activity at the adria microplate boundary in western slovenia and croatia.– in: bada, g. (eds.): quantitative neotectonics and seismic hazard assessment: new integrated approaches for environmental management. malév air tours, 74–75. placer, l. (2008): principles of the tectonic subdivision of slovenia.– geologija, 51, 205–217. doi: 10.5474/geologija.2008.021 placer, l., vrabec, m. & celarc, b. (2010): the bases for understanding of the nw dinarides and istria peninsula tectonics.– geologija, 53, 55–86. doi: 10.5474/ geologija.2010.005 poljak, m., živčić, m. & zupančič, p. (2000): the seismotectonic characteristics of slovenia.– pure appl. geophys., 157, 37–55. schmid, s.m., fügenschuh, b., kissling, e. & schuster, r. (2004): tectonic map and overall architecture of the alpine orogen – eclogae geol. helv., 97, 93–117. doi: 10.1007/s00015­004­1113­x schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine­ carpathian­dinaridic orogenic system: correlation and evolution of tectonic units.– swiss j. geosci., 101, 139–183. doi: 10.1007/s00015­008­1247­3 sperner, b. & zweigel, p. (2010): a plea for more caution in fault­slip analysis.– tectonophysics, 482/1–4, 29–41. doi: 10.1016/j.tecto.2009.07.019 tari, v. (2002): evolution of the northern and western dinarides: a tectonostratigra phic approach.– in: bertotti, g., schulmann, k. & cloetinghh, s.a.p.l. (eds.): continental collision and the tectono – sedimentary evolution of the forelands. egu stephan mueller special publication series, 1, 223–236. tomljenović, b. & csontos, l. (2001): neogene­quaternary structures in the border zone between alps, dinarides and pannonian basin (hrvatsko zagorje and karlovac basins, croatia).– int. j. earth sci., 90, 560–578. doi: 10.1007/ s005310000176 tomljenović, b., csontos, l., márton, e. & márton, p. (2008): tectonic evolution of the northwestern internal dinarides as constrained by structures and rotation of medvednica mountains, north croatia.– in: siegesmund, s., fügenschuh, b. & froitzheim, n. (eds.): tectonic aspects of the alpine­ dinaride­carpathian system. geological society, london, special publications, 298, 145–167. doi: 10.1144/sp298.8 turnšek, d., buser, s. & ramovš, a. (1982): triassic reefs in slovenia.– facies, 6, 15–24. ustaszewski, k., schmid, s.m., fügenschuh, b., tischler, m., kissling, e. & spakman, w. (2008): a map­view restoration of the alpine­ carpathian­dinaridic system for the early miocene.– swiss j. geosci., 101/1, 273–294. doi: 10.1007/s00015­008­1288­7 ustaszewski, k., kounov, a., schmid, s.m., schaltegger, u., krenn, e., frank, w. & fügeschuh, b. (2010): evolution of the adria­europe plate boundary in the northern dinarides: from continent­continent collision to back­ arc extension.– tectonics, 29, 1–34. doi:10.1029/2010tc002668 vrabec, m. & fodor, l. (2006): late cenozoic tectonics of slovenia: structural styles at the northeastern corner of the adriatic microplate.– in: pinter, n., grenerczy, g., weber, j., stein, s. & medak, d. (eds.): the adria microplate: gps geodesy, tectonics and hazards. nato science series, iv, earth and environmental sciences, 61, 151–168. wallace, r.e. (1951): geometry of shearing stress and relation to faulting.– j. geol., 59, 118–130. weber, j., vrabec, m., stopar, b., pavlovič­prešeren, p. & dixon, t. (2006): the pivo­2003 experiment: a gps study of istria peninsula and adria microplate motion, and active tectonics in slovenia.– in: pinter, n., grenerczy, g., weber, j., stein, s. & medak, d. (eds.): the adria microplate: gps geodesy, tectonics and hazards. nato science series, iv, earth and environmental sciences, 61, 305–320. weber, j., vrabec, m., pavlovič­prešeren, p., dixon, t., jiang, y. & stopar, b. (2010): gps­derived motion of the adriatic microplate from istria peninsula and po plain sites, and geodynamic implications.– tectonophysics, 483, 214–222. doi: 10.1016/j.tecto.2009.09.001 zajc, m., celarc, b. & gosar, a. (2015): structural­geological and karst feature investigations of the limestone­flysch thrust­fault contact using low­frequency ground penetrating radar (adria­dinarides thrust zone, sw slovenia).– environmental earth sciences, 73, 8237–8249. doi: 10.1007/s12665­014­3987­x žalohar, j. & vrabec, m. (2007): paleostress analysis of heterogeneous fault­slip data: the gauss method.– j. struct. geol., 29, 1798–1810. doi: 10.1016/j. jsg.2007.06.009 žalohar, j. & vrabec, m. (2008): combined kinematic and paleostress analysis of fault­slip data: the multiple­slip method.– j. struct. geol., 30, 1603–1613. doi: 10.1016/j.jsg.2008.09.004 žibret, l. & žibret, g. (2014): use of geomorphological indicators for the detection of active faults in southern part of ljubljana moor, slovenia.– acta geogr. slov., 54, 271–291. doi: 10.3986/ags54203 žibret, l. (2015): kinematic and paleostress evolution of the nw­se trending dina­ ric faults in the northwestern external dinarides.– unpubl. phd thesis, faculty of natural sciences and engineering, university of ljubljana, 84 p. 2016 | 69/3 | 337–345 | 7 figs. | 3 tabs. | www.geologia-croatica journal of the croatian geological survey and the croatian geological society upper cretaceous geosites on golija mountain – objects of geoheritage ljiljana grujičić-tešić1, dragoman rabrenović1, jovan kovačević2, nataša gerzina1 and nevenka đerić1 1 university of belgrade, faculty of mining and geology, đušina 7, 11000 belgrade, serbia; (natasa.gerzina@rgf.bg.ac.rs) 2 geological survey of serbia, rovinjska 12, 11000 belgrade, serbia doi: 10.4154/gc.2016.28 abstract the upper cretaceous rudist limestones are well-known from several localities in serbia. three of these localities (svilanovo, bele vode and kulizino selo) are located in sw serbia, on golija mt. these localities are crucial for understanding the development of the upper cretaceous shallow-water environments, thus this is an area of great scientific and educational value, particularly considering palaeontology, stratigraphy, palaeoecology and palaeogeography. one of the aims of this paper is to evaluate these geosites and their geotouristic potential, using geosite assessment model (gam), which is important for their geoconservation as well as for the sustainable development of the area. 1. introduction the systematic study of the geological heritage and geodiversity in serbia started relatively recently (maran, 2008, 2010; run­ dić & knežević, 2005; mijović et al., 2005; karamata & mijović 2005; stojanović & mijović, 2008; vujičić et al., 2011; jovanović et al., 2012; rabrenović et al., 2014; maran stevanović, 2015). an inventory of serbian geo­ heritage sites includes approximately 650 geological, palaeonto­ logical, geomorphological, spelaeological and neotectonic sites (đurović & mijović, 2006). this study focuses on the upper cretaceous limestone with rudist fauna in the area between sjenica and raška (fig. 1). here, there are several outcrops of major importance for scientific know ledge and study of upper cretaceous fossiliferous sedi­ ments. however, considering their geological and palaeontologi­ cal characteristics, only three of these localities (svilanovo, kuli­ zino selo and bele vode) seem to be interesting from the aspect of geological heritage. these localities are very important from the geological point of view, thus the aim of this paper is to pre­ sent the main scientific arguments for considering these localities to be a part of serbian geoheritage. remains of rudist limestones are scattered on the slopes of mt. golija which is the highest mountain in sw serbia. mt. golija has been under state protection as the golija nature park, since 2001. the golija nature park was placed in cat­ egory i as a natural resource of exceptional importance. be­ cause of the exceptionally well­preserved natural environment, but also because of its cultural resources, the committee of the unesco’s man and the biosphere programme (mab) set up the golija­studenica biosphere reserve within the golija nature park. besides their scientific significance, the beautiful landscape and cultural heritage reveal the high tou ristic poten­ tial of these localities, thus making them quite important from educational, touristic and cultural points of view. all the three localities are easily accessible, since they are situated along as­ phalt roads. the main purpose of this paper is to evaluate different ge­ osites using the preliminary geosite assessment model (gam) proposed by vujičić et al. (2011) in order to determine whether this area has the potential for geotourism development. 2. geological setting and geosites selection the region of western and southwestern serbia is characterized by an extremely complex geological setting, as a result of col­ lisional processes between the adria microplate and the euro­ pean plate. the area is composed of the continental drina­ivan­ jica, jadar­kopaonik and east­bosnian­durmitor units, as well as two ophiolite belts, which are remnants of oceanic crust that are derived from the neotethys (dimitrijević & dimi­ trije vić, 1973; robertson & karamata, 1994; dimi­ trije vić, 2001; karamata, 2006). recent investigations show ed that the double belt appearance (western vardar zone and dinaridic ophiolite belt) and complicated present day geo­ logical relationships between the continental and oceanic units are the results of late jurassic obduction, followed by strong folding and out of sequence thrusting (pamić et al., 1998; hrvatović & pa mić, 2005; csontos et al., 2003; schmid et al., 2008). the late jurassic to early cretaceous transgressive phase, characterized predominantly by alluvial to neritic sedimentation, started after obduction and subsequent erosion in the dinaridic­ hellenic belt (pamić et al., 1998; pamić & hrvatović, 2000; schmid et al., 2008). in western and southwestern ser­ bia, however, these sediments are absent, possibly due to early to mid­cretaceous collisional processes (schmid et al., 2008). in this region, both palaeozoic and mesozoic sediments of the drina­ivanjica and jadar­kopaonik units, which derived from the passive margin of adria, and jurassic rocks of oceanic origin that belong to the vardar zone, are unconformably overlain by upper cretaceous transgressive clastic sediments containing re­ deposited ophiolite fragments. carbonate and terrigenous­carbo­ nate sedimentation followed through the upper cretaceous until article history: manuscript received march 25, 2016 revised manuscript accepted august 16, 2016 available online october 25, 2016 keywords: geoheritage, geosite, geoconservation, geotourism, rudists, upper cretaceous, mt. golija, sw serbia g eo lo gi a c ro at ic a geologia croatica 69/3338 in the area between čačak and novi pazar, outcrops of the upper cretaceous rudist limestone occur in the form of a narrow strip along the rim of the overlying flysch deposits. there are also several small lenslike bodies of rudist limestone on the northern slopes of golija mountain. with an abundance of exceptionally large and well­preserved fossils, three localities at which the up­ per cretaceous limestone are exposed, svilanovo, kulizino selo and bele vode, should be considered as potentially important for serbian geoheritage (fig. 1). svilanovo village is located on the southern slopes of mt. go­ li ja, about seven kilometres from the mountain peak odvra će nica (n 43º14’40” e 20º19’54”). direct access to the locality is along a good asphalt road that branches from the novi pazar­golija road. lying over low­grade metamorphosed schists of carboniferous age, upper cretaceous rudist limestone makes a conspicuous, more than 500 m long scarp along a relatively steep slope (fig. 2). the massive biomicritic limestone was deposited under shal­ low­water conditions. a heterogeneous fossil association com­ prises foraminifers, detritus of bivalves, gastropods, echinoids, corals, etc. (fig. 3). the dominant macrofossils are rudist bivalves (fig. 4) from the genera radiolites, lapeirouseia, pironea, hippurites, etc. (ćirić, 1996). in the nearby vicinity, another profile of upper cretaceous rudist limestone is exposed in the village of bele vode, on the northern slopes of golija mountain, along the ivanjica­golija road the maastrichtian when flysch sedimentation began (mojsilović et al., 1980; filipović et al., 1978). the wider investigated area belongs to the cretaceous cover of palaeozoic rocks on the eastern rim of the drina­ivanjica unit, i.e. to a belt of cretaceous sediments, known as „novi pazar cre­ taceous„ (rampnoux, 1970) that can be traced from kosovo towards the north and northwest to the area of dragačevo. the complete cretaceous stratigraphic sequence can be traced only in the western part of this belt. in this area, the cretaceous sedimentary succession begins with a 30 m thick basal conglomerate and conglomeratic lime­ stone succession, which is overlain by a shallow­water limestone with santonian­campanian fauna represented by hippuritids, ra­ diolitids, globotruncanids, gastropods and echinoids which is about 50 m thick. rudist limestones are generally considered as products of typical reefal sedimentation (e.g. milovanović, 1960; ross, 1992; koch et al., 2002). however, there are other opinions (e.g. gili et al., 1995; sanders, 1998) suggesting that cretaceous rudists were unable to build bioherms similar to holo­ cene coral reefs, but were gregarious sediment­dwelling aclonal suspension feeders. cretaceous sedimentation ends with a thick sequence of preflysch and flysch sediments of campanian and maastrichtian age (rampnoux, 1964, petrović & janki­ če vić, 1988), i.e. the so­called kosovska mitrovica flysch (di­ mi trijević & dimitrijević, 1987; dimitrijević, 1997). figure 1. a simplified and modified geological map of the wider surroundings of the investigated area, based on the geological map of sfry 1:500000 (savezni geološki zavod, 1970). g eologia c roatica grujičić-tešić et al.: upper cretaceous geosites on golija mountain – objects of geoheritage 339 (n 43º24’09” e 20º17’50”). at this locality, upper cretaceous sediments transgressively overlie carboniferous schists. the up­ per cretaceous sequence starts with clastic sediments which are overlain by light gray biomicritic limestone with abundant ru­ dists, corals and echinoids. the sedimentation regime was occa­ sionally interrupted by the inflow of clayey­silty material, which resulted in the occurrence of several metres of bedded marly limestone. the succession ends with a massive limestone that contains rudists from the genera lapeirouseia, hippurites, radiolites, pironea, etc. (fig. 5). the third locality is situated in the village of kulizino selo, south of bele vode (n 43º22’55” e 20º17’32”). at this locality, cre­ taceous rudist limestone lies above a relatively thin sequence com­ posed of clastic sediments. a horizon of yellowish clayey limestone with densely packed small rudists, other bivalves and gastropods occurs within the massive limestone with large rudists (fig. 6). ru­ dists at this locality mostly belong to the following genera: lapeirouseia, vaccinites, hippurites, radiolites and pironea. the most important rudist specimen belongs to the species lapeirouseia crateriformis. with a diameter of the upper valve of more than 60 cm, it is the largest rudist ever found in the dinarides (ćirić, 1996). these geosites are important for understanding the evolution of the wider region of golija mountain, making this area of great scientific value, particularly considering palaeontology, stratig­ raphy, palaeoecology and palaeogeography. eastern and central mediterranean rudist species vaccinites atheniensis ktenas (younger synonym of v. chaperi; steuber, 1999), occurring at all these localities (milovanović, 1975), figure 2. scarp composed of upper cretaceous rudist limestone, svilanovo village. figure 4. a rudist bivalve in growth position. figure 3. abundant fossils in upper cretaceous limestone, locality svilanovo. figure 6. a large rudist specimen, kulizino selo locality. figure 5. limestone with rudist bivalves at the locality of bele vode. g eo lo gi a c ro at ic a geologia croatica 69/3340 can be used for correlation with sedimentary rocks from distant regions. according to milovanović (1934), in the terrains of serbia (vicinity of kosovska mitrovica, novi pazar, raška, go­ lija) this species belongs to the same association as in the gossau cretaceous sediments of the eastern alps, thus it should have the same stratigraphic position as in the eastern alps, i.e. late santonian – early campanian. recent chemostratigraphic ages reported from the surrounding regions (swinburne at al., 1992) indicate the campanian age of similar rudist­bearing lime­ stones. besides, these sediments show strong similarities to the limestone of the pučišća fm. in the eastern part of brač (vicinity of povlja) in croatia, which are assigned an early campanian age (steuber et el., 2005). therefore, considering the absence of micropalaeontological data from our localities and the recently revised ages of similar rudist associations in the wider region, the general age of the rudist limestone on golija mt. is probably cam­ panian (?early campanian). 3. methods there are numerous papers on the evaluation of geosites world­ wide (e.g. henriques et al., 2011; tomić, 2011; vujičić et al., 2011; moufti et al., 2013; petrović et al., 2013; vasi­ lje vić et al., 2014; gnezdilova et al., 2015; boškov et al., 2015; began & višnić, 2015). different methods have been proposed for geoheritage assessment (e.g. pralong, 2005; pereira et al., 2007; reynard et al., 2007; vujičić et al., 2011; fassoulas et al., 2012; tomić & božić, 2014; ma­ ran stevanović, 2015) based on quantification of different characteristics of geosites. in this paper, evaluation of the chosen localities is based on the preliminary geosite assessment model (gam), created by vujičić et al. (2011). this method involves the quantification of two groups of indicators. the first group (main values) comprises scientific/educational (vse), scenic/aesthetical (vsa) and pro­ tection (vpr) values. these values are crucial for geoheritage as­ sessment. however, the other group of indicators (additional va­ lues), which includes functional (vfn) and touristic values (vtr), is important for considering the geotouristic potential of a site. all indicators are assigned values grading from 0 to 1. after evaluating each element in both groups of indicators, the total value was calculated for each group. the results obtained are presented in a discrimination diagram, where the main and additional values for each site are plotted against each other along the x and y axes, respectively. the matrix is divided into nine fields and the position of each geosite within one of these fields shows its importance as an object of geoheritage and sug­ gests plans of action for protection and sustainable management of the geosite. 4. results and discussion with the aim of evaluating the geosites on golija mt., three lo­ calities have been studied as potentially interesting sites of geo­ heritage significance. main and additional values for each sub­ indicator are given in tables 1 and 2, respectively. according to moufti et al. (2013), short explanations for the assigned values are given in tables 1 and 2. the total scores of the main indica­ tors were plotted against the values of the additional indicators (fig. 7). the svilanovo locality has a high value of main (8.75) and medium value of additional (7.75) indicators. the overall grade puts the svilanovo locality (gs1) in the z32 cell (fig. 7). the value of the main indicators (table 1) is relatively high, considering the fact that there is no formal protection whatsoever. additional va­ lues (table 2) are at a moderate­to­high level due to a poorly de­ veloped touristic sector (no promotion, interpretative panels or tour guide service). the bele vode locality (gs2) is in the z22 field (fig. 7). the main indicator value (7.75) for this locality is somewhat lower due to the fact that there was short­lived limestone exploitation at this locality (table 1). additional indicators value (7.25) is also slightly lower than in the previous locality (table 2). the third locality, kulizino selo (gs3) falls on the boundary between z22 and z32 (fig. 7). the overall main indicators value (8.00) is quite similar to that of the previous two localities (table 1), but the final grade is lower due to the much lower values of the additional indicators (6.50; table 2). finally, we compared our results with other geological and geomorphological sites evaluated using the same method, i.e. the localities on fruška gora mt. (vujičić et al., 2011; petrović et al., 2013) and papuk mt. (petrović et al., 2013), as well as in bela crkva municipality (boškov et al., 2015) and other evaluated geomorphological geosites in se serbia (began & višnić, 2015) (table 3). it is evident from fig. 7 that, according to the mean main indicator values, the analyzed geosites on golija mt., as all other geosites in the region that were previously evaluated by gam method, fall in the fields z2y and z3y (y=1,2,3). this indicates their scientific significance and potential for geotourism and ge­ oconservation. the obtained data show that the mean value for the group of indicators of main values for the studied geosites on golija mt. (8.16) is slightly higher than for most of the other evaluated sites in the region. analysis of different subindicators of main values shows that although vse and vpr are balanced and relatively figure 7. location of the assessed geosites (gs 1 – svilanovo, gs 2 – bele vode, gs 3 – kulizino selo) in gam matrix, together with other previously evaluated geosites in the region. legend: – geosites on fruška gora mt. (vujičić et al., 2011); – geosites on papuk mt. (petrović et al., 2013); – geosites in bela crkva municipality (boškov et al., 2015); – geosites in se serbia (began & višnić, 2015). mean values for each group of geosites is presented by large symbols. g eologia c roatica grujičić-tešić et al.: upper cretaceous geosites on golija mountain – objects of geoheritage 341 table 1. main values (according to the gam method proposed by vujičić et al., 2011) of geosites of golija mt. geosites/geotopes svilanovo bele vode kulizino selo i scientific/educational values (vse) 1. rarity common=0 regional=0.25 national=0.5 0.5 – upper cretaceous limestone with rudist fauna, rare in the serbian part of the dinarides, probably not so unique globally 0.5 – upper cretaceous limestone with rudist fauna, rare in the serbian part of the dinarides, probably not so unique globally 0.5 – upper cretaceous limestone with rudist fauna, rare in the serbian part of the dinarides, probably not so unique globally international=0.75 the only occurrence=1 2. representativeness none=0 low=0.25 moderate=0.5 0.5 – fairly representative for upper cretaceous rudist-bearing carbonate platform environment 0.5 – fairly representative for upper cretaceous rudist-bearing carbonate platform environment high=0.75 0.75 – representative for upper cretaceous rudist-bearing carbonate platform environment in western serbia, similar outcrops are known elsewhere utmost=1 3. knowledge on geo-scientific issues none=0 local publications=0.25 regional publications=0.5 national publications=0.75 0.75 – locality known from national geological literature 0.75 – locality known from national geological literature 0.75 – locality known from national geological literature international publications=1 4. level of interpretation none=0 moderate level of processes but hard to explain to non experts=0.25 0.25 – relatively good example of upper cretaceous reef-like bioconstructions; basic geological knowledge necessary to understand the palaeoenvironment 0.25 – relatively good example of upper cretaceous reef-like bioconstructions; basic geological knowledge necessary to understand the palaeoenvironment good example of processes but hard to explain to non experts=0.5 0.5 – perfect example of cretaceous reef-like bioconstructions, but basic geological knowledge necessary to understand the palaeoenvironment moderate level of processes but easy to explain to common visitor=0.75 good example of processes and easy to explain to common visitor=1 ii scenic/aesthetic values (vsa) 1. viewpoints (each must present a particular angle of view and be situated less than 1 km from the site) none=0 one=0.25 2 to 3=0.5 0.5 – transgressive boundary between the late palaeozoic metamorphics and the upper cretaceous limestone; a miocene volcanic neck with columnar jointing in the vicinity 0.5 – upper cretaceous rudist limestone; late palaeozoic metamorphics nearby 0.5 – upper cretaceous rudist limestone; late palaeozoic metamorphics nearby 4 to 6=0.75 more than 6=1 2. surface (each considered in quantitative relation to other) small=0 sm=0.25 medium=0.5 ml=0.75 large=1 1-the area is several 100s of metres in size 1-the area is several 100s of metres in size 1-the area is several 100s of metres in size 3. surrounding landscape and nature minimum = 0 low=0.25 medium-0.5 high=0.75 0.75 – situated in a beautiful valley. the locality is surrounded by sparsely wooded topography with meadows and pastures utmost=1 1 – from the top of golija mt., adorable view of the pešter plateau (sjeničko polje and novopazarsko polje). the locality is surrounded by sparsely wooded topography with meadows and pastures 1 – situated on a slope with beautiful view of the top of the golija mt and the kopaonik mt. the locality is surrounded by sparsely wooded topography with meadows and pastures 4. environmental fitting of sites unfitting=0 un=0.25 neutral=0.5 nf=0.75 0.75 – limestone exploitation started at this locality, but it was shortlived fitting=1 1 – perfect representation of the location 1 – perfect representation of the location g eo lo gi a c ro at ic a geologia croatica 69/3342 iii protection (vpr) 1. current condition totally damaged (as a result of human activities)=0 highly damaged (as a result of natural processes)=0.25 medium damaged (with essential geomorphologic features preserved) = 0.5 slightly damaged=0.75 0.75 – effects of previous exploitation still visible on the site no damage=1 1 – completely preserved site 1 – completely preserved site 2. protection level none=0 0-no formal protection 0-no formal protection 0-no formal protection local=0.25 reginal=0.5 national=0.75 international=1 3. vulnerability irreversible (with possibility of total loss)=0 high (could be easily damaged)=0.25 medium (could be damaged by natural processes or human activities)=0.5 low (could be damaged only by human activities)=0.75 0.75 – potential collectors of rudists could damage the outcrop faces 0.75 – potential collectors of rudists could damage the outcrop faces 0.75 – potential collectors of rudists could damage the outcrop faces none=1 4. suitable number of visitors zero=0 0 to 10=0.25 10 to 20=0.5 20 to 50=0.75 more than 50=1 1 – the open places can hold more than 50 visitors at any one time 1 – the open places can hold more than 50 visitors at any one time 1 – the open places can hold more than 50 visitors at any one time total (vse+vsa+vpr) 8.75 7.75 8.00 table 2. additional values (according to the gam method proposed by vujičić et al., 2011) of geosites of golija mt. geosites/geotopes svilanovo bele vode kulizino selo i functional values (vfn) 1. accessibility inaccessible=0 low (on foot with special equipment and expert guide tours)=0.25 medium (by bicycle and other means of man-powered transport)=0.5 high (by car)=0.75 0.75 – the site is along the road, easily accessible by car utmost (by bus)=1 1 – the site is along the road, easily accessible by bus 1 – the site is along the road, easily accessible by bus 2. additional natural values none=0 one=0.25 0.25 – a site of pyramidal fir (abies alba var. pyramidalis) 2 to 3=0.5 0.5 – a site of pyramidal fir (abies alba var. pyramidalis); a lot of springs in the vicinity 0.5 – a site of pyramidal fir (abies alba var. pyramidalis); a lot of springs in the vicinity 4 to 6=0.75 more than 6=1 3. additional anthropogenic values none=0 one=0.25 2 to 3=0.5 4 to 6=0.75 0.75 – plantations of raspberries; orthodox medieval monasteries of studenica, gradac, đurđevi stupovi and sopoćani; saint apostles peter and paul church, the oldest in the balkans. more than 6=1 1 – seasonal mountain settlements („katuni„); plantations of raspberries; orthodox medieval monasteries of studenica, gradac, đurđevi stupovi and sopoćani; saint apostles peter and paul church, the oldest in the balkans. 1 – several sculpture fountains; plantations of raspberries; orthodox medieval monasteries of studenica, gradac, đurđevi stupovi and sopoćani; saint apostles peter and paul church, the oldest in the balkans. g eologia c roatica grujičić-tešić et al.: upper cretaceous geosites on golija mountain – objects of geoheritage 343 4. vicinity of emissive centres more than 100 km=0 100 to 50 km=0.25 50 to 25 km=0.5 0.5 – 30km from ivanjica 0.5 – 35km from ivanjica 25 to 5 km=0.75 0.75 – 20km from novi pazar less than 5 km=1 5. vicinity of important road network none=0 local=0.25 0.25 – the asphalt road novi pazar-golija 0.25 – the local asphalt road 0.25 the local asphalt road regional=0.5 national=0.75 international=1 6. additional functional values none=0 low=0.25 medium=0.5 high=0.75 utmost=1 1 – along the asphalt road to novi pazar-golija and sjenica-golija 1 – along the asphalt road to the village of bele vode 1 – along the asphalt road to the village of kulizino selo ii touristic values (vtr) 1. promotion none=0 0 0 0 local=0.25 regional=0.5 national=0.75 international=1 2. annual number of organized visits none =0 less than 12 per year=0.25 0.25 – geologists, geology students 0.25 – geologists, geology students 0.25 – geologists, geology students 12 to 24 per year=0.5 24 to 48 per year=0.75 more than 48 per year=1 3. vicinity of visitors centre more than 50 km=0 50 to 20 km=0.25 20 to 5 km=0.5 0.5 – rural tourism 0.5 – rural tourism 5 to 1 km=0.75 0.75 – in the golija nature park less than 1 km=1 4. interpretative panels (characteristics of text and graphics, material quality, size, fitting to surroundings, etc.) none=0 0 0 0 low quality=0.25 medium quality=0.5 high quality=0.75 utmost quality=1 5. annual number of visitors none =0 low (less than 5000)=0.25 0.25 0.25 0.25 medium (5001 to 10.000)=0.5 high (10.001 to 100.000)=0.75 utmost (more than 100.000)=1 6. tourism infrastructure (pedestrian pathways, resting places, garbage cans, toilets, wellsprings etc.) none=0 low=0.25 medium=0.5 0.5 – pedestrian paths in the vicinity, wellsprings 0.5 – pedestrian paths in the vicinity, wellsprings 0.5 – pedestrian paths in the vicinity, wellsprings high=0.75 utmost=1 7. tour guide service (expertise level, knowledge of foreign language(s), interpretative skills, etc) none=0 0 0 0 low=0.25 medium=0.5 high=0.75 utmost=1 8. hostelry service more than 50 km=0 25-50 km=0.25 10-25 km = 0.5 0.5 – on golija mt 0.5 – on golija mt 5-10 km=0.75 less than 5 km=1 1 – on golija mt 9. restaurant service more than 25 km=0 10-25 km=0.25 10-5 km=0.5 5-1 km=0.75 0.75 – on golija mt 0.75 – village tavern nearby less than 1 km=1 1 – village tavern nearby total (vfn + vtr) 7.75 7.25 6.50 g eo lo gi a c ro at ic a geologia croatica 69/3344 high, the differences in main values mostly depend on vsa. the highest vsa for the studied geosites on golija mt. (3.33) are due to the large surface areas of the outcrops, the beautiful landscape and their untouched nature. most of the subindicators represent­ ing protection (vpr) are very high for geosites on golija mt., but they are significantly lowered due to the lack of any kind of for­ mal protection. although vse for sites on golija mt. are quite satisfactory (2.16), low values of level of interpretation show that these geosites might be interesting in the first instance for people with a geoscience background. the calculated mean additional values of different groups of geosites greatly differ (from zx1 to zx3, x=1,2,3), depending on the overall development of an area, the number of potential visi­ tors, touristic infrastructure, management and planning, vicinity of emissive centres, etc. mean values for the group of indicators of additional values for the studied localities are much lower than for geosites on papuk mt. and in se serbia, but much higher than for those on fruška gora mt. and in bela crkva municipality. despite rather similar functional values (vfn) to geosites is se serbia and generally higher than those on papuk mt., geosites on golija mt. have much lower touristic values (vtr). the main reason for this is insufficient development of tourism in this area. such low vtr obtained for the studied geosites are compensated for by relatively high vfn, which results in generally high addi­ tional values. 5. conclusions the obtained results show that the main indicators values of the analyzed geosites are high and that these localities are important from a scientific and educational point of view, which leads to the conclusion that golija mountain has sufficient levels of natural resources for geotourism development. the additional indicators values are at a medium level in all three geosites. this is not surprising, considering the fact that this is a problem for many potential sites of geoheritage signifi­ cance in serbia, because of the lack of organized visits, tour guide service, interpretative panels, etc. this implies that there is an urgent need for more rapid, though sustainable, development of the tourism infrastructure. in order to maintain the original characteristics of these ge­ osites, it would be necessary to protect them from negative influ­ ences that might result in degradation or complete devastation. the final aim is geoconservation of the geosites in their original, undisturbed condition, in order to preserve it for future genera­ tions. the most effective way of protection of objects of geoheritage significance is to raise the awareness of their scientific, educational, aesthetic and touristic importance, as well as to forbid their commercial exploitation. this paper shows that all the studied localities fully deserve such treatment. acknowledgment the work was supported by the ministry of education, science and technological development of the republic of serbia (pro­ ject no. 176015). we also thank the editor and two anonymous reviewers for their constructive comments, which helped us to improve the manuscript. references began, m. & višnić, t. (2015): comparative analysis of gorges and canyons in southeastern serbia as potential geotouristic destinations by using gam model.– asian journal of multidisciplinary studies, 3/11, 4–11. boškov, j., kotria, s., jovanović, m., tomić, n., lukić, t. & rvović, i. (2015): аpplication of the preliminary geosite assessment model (gam): the case of the bela crkva municipality (vojvodina, north serbia).– geographica pannonica, 19/3, 146–152. csontos, l., gerzina, n., hrvatović, h., schmid, s. & tomljenović, b. (2003): structure of the dinarides: a working model.– ann. univ. sci. budapest., sect. geol., 35, 143–144. ćirić, b. (1996): geologija srbije [geology of serbia – in serbian].– geokarta, be­ ograd, 273 p. dimitrijević, m.d. (1997): geology of yugoslavia.– geol. inst. gemini spec. pu­ bl., belgrade, 187 p. dimitrijević, m.d. (2001): dinarides and the vardar zone: a short review of the ge­ ology.– acta vulcanol., 13, 1–8. dimitrijević, m.n. & dimitrijević, m.d. (1973): olistostrome mélange in the yugoslavian dinarides and late mesozoic plate tectonics.– j. geol., 81/3, 328–340. dimitrijević, m.n. & dimitrijević, m.d. (1987): the titova mitrovica flysch.– in: dimitrijević, m.n. & dimitrijević, m.d. (eds.): the trubiditic basins of serbia. serbian academy of sciences and arts department of natural & mathe­ matical sciences, 61, 25–64. đurović, p. & mijović, d. (2006): geonasleđe srbije – reprezent njenog ukupnog geodiverziteta [geoheritage of serbia-representative of its total geodiversity – in serbian].– zbornik radova geografskog fakulteta u beogradu, 54, 5–18. fassoulas, c., mouriki, d., dimitriou-nikolakis, p. & iliopoulos, g. (2012): quantitative assessment of geotopes as an effective tool for geoheritage management.– geoheritage, 4, 177–193. filipović, i., marković, b., pavlović, z., rodin, v. & marković, o. (1978): osnovna geološka karta sfrj 1: 100000. tumač za list gornji milanovac l34-137 [basic geologic map of sfry 1: 100.000. explanatory booklet for the sheet gornji milanovac – in serbian].– savezni geološki zavod, beograd. gili, e., masse, j-p. & skelton. p.w. (1995): rudists as gregarious sediment dwell­ ers, not reef-builders, on cretaceous carbonate platforms.– palaeogeography, palaeoclimatology, palaeoecology, 118, 245–267. gnezdilova, v., ruban, d., bruno, d., perrotta, p., crowley, b., ohe­ im, k. & zayats, p. (2015): geoheritage sites with palaeogeographical value: some geotourism perspectives with examples from mountainous adygeja (rus­ sia).– geološki anali balkanskoga poluostrva, 76, 93–104. henriques, m., brilha, j., mota, t. & pena dos reis, r. (2011): geocon­ servation as an emerging geoscience.– geoheritage, 3/2, 117–128. hrvatović, h. & pamić., j. (2005): principal thrust­nappe structures of the dina­ rides. – acta geologica hungarica, 48/2, 133–151. jovanović, v., carević, i., vušković, d. & khalil abad, t.m. (2012): re­ view and protection possibilities of some trans-border (east serbia – west bul­ garia) stratigraphic/palaeontological geosites.– bulletin of the serbian geographical society, 92/1, 171–184. karamata, s. (2006): the geological development of the balkan peninsula related to the approach, collision and compression of gondwana and eurasian units.– in: robertson, a.h.f. & mountrakis, d. (eds.): tectonic development of the eastern mediterranean region.– geol. soc. london, spec. publ.,260, 155–178. table 3. mean main and additional values for different geosites in croatia and serbia, according to the gam method proposed by vujičić et al., 2011. geosites papuk mt. (according to petrović et al., 2013) fruška gora mt. (according to vujičić et al., 2011) bela crkva municipality (according to boškov et al., 2015) se serbia (according to began & višnić, 2015) golija mt. (this publication) mean main values 7.57 7.02 7.70 8.55 8.15 vse 2.43 2.46 2.00 3.30 2.16 vsa 2.71 2.43 2.83 2.56 3.33 vpr 2.43 2.13 2.87 2.69 2.66 mean additional values 10.25 4.29 4.00 8.90 7.16 vfn 3.61 2.94 2.37 4.50 4.08 vtr 6.64 1.35 1.63 4.40 3.08 g eologia c roatica grujičić-tešić et al.: upper cretaceous geosites on golija mountain – objects of geoheritage 345 karamata, s. & mijović, d. (2005): inventar objekata geonasleđa srbije [inventory of the geological heritage sites of serbia – in serbian, english abstract].– in: mijović, d. (ed.): ii intern. symp. on geoheritage of serbia. bull. inst. of nature conserv., sp. issue, 20, 1–36. koch, r., moussavian, e., ogorelec, b., skaberne, d. & bucur, i. (2002): development of a lithocodium (syn. bacinella irregularis)­reef­mound­ a patch reef within middle aptian lagoonal limestone sequence near nova gorica (sabotin mountain, w­slovenia).– geologija, 45/1, 71–90. maran, a. (2008): geoconservation in the balkan region – practices and legal instru­ ments.– bulletin of the natural history museum, belgrade, 1, 41–63. maran, a. (2010): valuing the geological heritage of serbia.– bulletin of the natural history museum, belgrade, 3, 47–66. maran stevanović, a. (2015): methodological guidelines for geoheritage site assessment: a proposal for serbia.– geološki anali balkanskoga poluostrva, 76, 105–113. mijović, d., rundić, lj. & milovanović, d. (2005): zaštita geonasleđa u srbiji i pravci razvoja [protection of geoheritage of serbia and future development – in serbian, english abstract].– in: mijović, d. (ed.): ii intern. symp. on geo­ heritage of serbia. bull. inst. of nature conserv., sp. issue, 20, 17–21. milovanović, b. (1934): rudisna fauna jugoslavije, istočna srbija, zapadna srbija, stara raška [rudist fauna of yugoslavia, eastern serbia, western serbia, stara raška – in serbian].– geološki anali balkanskoga poluostrva, 12/1, 186–213. milovanović, b. (1960): stratigraphie du sénonien dans les dinarides yougoslaves d’après les rudistes.– bull. soc. géol. france, 7/2, 366–375. milovanović, b. (1975): jugozapadna srbija.[southwestern serbia].– in: petko­ vic, k. (ed.): geologija srbije, ii­2, stratigrafija, mezozoik. zavod za regionalnu geologiju i paleontologiju rudarsko­geološkog fakulteta, univerzitet u beogradu, 327–331. mojsilović, s., baklajić, d. & đoković, i., (1980): osnovna geološka karta sfrj 1: 100000. tumač za list sjenica [basic geologic map of sfry 1: 100.000. explanatory booklet for the sheet sjenica – in serbian].– savezni geološki zavod, beograd, 46 p. moufti, m.r., németh, k., el­masry, n. & qaddah, a. (2013): geoheritage values of one of the largest maar craters in the arabian peninsula: the al wahbah crater and other volcanoes (harrat kishb, saudi arabia).– central european jour­ nal of geosciences, 5/2, 254–271. pamić, j., gušić, i. & jelaska, v. (1998): geodynamic evolution of the central dinarides.– tectonophysics, 297, 251–268. pamić, j. & hrvatović, h. (2000): dinaride ophiolite zone (doz).– in: pamić, j. & tomljenović, b. (eds.): pancardi 2000 fieldtrip guidebook.– vijesti, 37/2, 60–68. pereira, p., pereira, d. & caetano alves, m.i. (2007): geomorphosite assess­ ment in montesinho natural park (portugal).– geographica helvetica, 62, 159–168. petrović, m. & jankičević, j. (1988): stratigraphic column of the upper creta­ ceous near novi pazar.– geološki anali balkanskoga poluostrva, 52, 107–113. petrović, m.d., vasiljević, dj.a., vujičić, m.d., hose, t.a., marković, s. b. & lukić, t. (2013): global geopark and candidate – comparative analysis of papuk mountain geopark (croatia) and fruška gora mountain (serbia) by us­ ing gam model.– carpathian journal of earth and environmental sciences, 8/1, 105–116. pralong, j.p. (2005): a method for assessing the tourist potential and use of geomor­ phological sites. – géomorphologie: relief, processus, environnement, 3, 189–196. rabrenović, d., belij, s., mojsić, i. & mladenović, m. (2014): main va­ lues of the đerdap area, potential geopark.– in: cvetković, v. (ed.): proceedings of the xvi serbian geological congress, donji milanovac, may 22­25, 866–871. rampnoux, j.­p. (1964): sur le cretace du versant ouest du kopaonik région de novi pazar (stara raška) yugoslavia.– bull. soc. géol. france, 7, vi/2, 219–224. rampnoux, j.­p. (1970): regards sur les dinarides internes yougoslaves (serbie mon­ ténégro oriental): stratigraphie, évolution paléogéographique, magmatisme.– bull. soc. géol. france, 12/6, 948–966. reynard, e., fontana, g., kozlik, l. & scapozza, c. (2007): a method for assessing „scientific” and „additional values” of geomorphosites.– geographica helvetica, 62/3, 148–158. robertson, a.h.f. & karamata, s. (1994): the role of subduction­accretion processes in the tectonic evolution of the mesozoic tethys in serbia.– tectono­ physics, 234, 73–94. ross, d.j. (1992): sedimentology and depositional profile of a mid­cretaceous shelf edge rudist reef complex, nahal ha’mearot, nw israel.– sedimentary geology, 79, 161–172. rundić, lj. & knežević, s. (2005): stratigrafsko­paleontološki objekti kao in­ tegralni deo geonasledja srbije [stratigraphical and palaeontological objects as an integral part of serbian geoheritage – in serbian, english abstract].– in: mijović, d. (ed.): ii intern. symp. on geoheritage of serbia., bull. inst. of nature conserv., sp. issue, 20, 109–114. sanders, d. (1998): upper cretaceous „rudist formations„.– geol. palëont. mitt. innsbruck., 23, 37–59. savezni geološki zavod (federal geological survey) (1970): geološka karta sfr jugoslavije, 1:500000 [geologic map of sfry, 1:500.000], beograd. schmid, m.s., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine­ carpathian­dinaridic orogenic system: correlation and evolution of tectonic units.– swiss j. geosci., 101/1, 139–183. steuber, t. (1999): cretaceous rudists of boeotia, central greece.– spec. papers in paleontology, 61, 229 p. steuber, t., korbar, t., jelaska, v. & gušić, i. (2005): strontium­isotope stratigraphy of upper cretaceous platform carbonates of the island of brač (adri­ atic sea, croatia): implications for global correlation of platform evolution and biostratigraphy.– cretaceous research, 26/5, 741–756. stojanović, v. & mijović, d. (2008): evaluation of geodiversity of the wes­ tern bačka danube region in the planning documents and opportunities for improvement.– collection of papers geographical institute „jovan cvijić„, 58, 5–16. swinburne, n.h.m., bilotte, m. & pamouktchiev, a. (1992): the stratig­ raphy of the campanian­maastrichtian rudist beds of bulgaria and reassessment of the range of the genus pironea.– cretaceous res., 13, 191–205. tomić, n. (2011): the potential of lazar canyon (serbia) as a geotourism destination: inventory and evaluation.– geographica pannonica, 15/3, 103–112. tomić, n. & božić, s. (2014): a modified geosite assessment model (m­gam) and its application on the lazar canyon area (serbia).– int. j. environ. res., 8/4, 1041–1052. vasiljević, dj.a., marković, s.b., hose, t.a., ding, z., guo, z., liu, x., smalley, i., lukić, t. & vujičić, m.d. (2014): loess–palaeosoil sequenc­ es in china and europe: common values and geoconservation issues.– catena, 117, 108–118. vujičić, m.d., vasiljević, dj.a., marković, s.b., hose, t.a., lukić, t. & hadžić, o. (2011): preliminary geosite assessment model (gam) and its ap­ plication on fruška gora mountain, potential geotourism destination of serbia.– acta geographica slovenica, 51/2, 361–377. 2020 | 73/3 | 143–151 | 6 figs. | 1 tab. | 2 pls. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction various mesozoic radiolarite deposits are common and wide­ spread in the territory of western and southwestern serbia. meso­ zoic radiolaria are found in pelagic and hemipelagic sediments deposited on the neo-tethys ocean floor, intercalated between triassic shallow-water carbonate ramp and platform sediments, and are widespread in jurassic times on the adriatic margin. their age determination, stratigraphy, and facies are important for the reconstruction of tectonic motion and the arrangement of palaeo­oceanic basins and continental blocks. due to the highly complicated structure of this territory, each palaeontological da­ tum from radiolarite deposits and from carbonate clasts of the intercalated turbidites is highly important. radiolarians are the most often utilized fossils in such bi­ ostratigraphic studies, due to their common presence in the mesozoic radiolarites. mesozoic radiolarian biochronology is essential for the understanding of the palaeogeography and overall tectonic structure of the dinarides. there are numerous data on siliceous sedimentary rocks associated with the ophiolite belts in the dina­ rides, albanides and hellenides which are often middle to late triassic, middle jurassic, or late middle jurassic to late jurassic in age (obradović & goričan, 1988; djerić et al., 2007; chiari et al., 2011; ferrière et al., 2015; gawlick et al., 2017; bragin et al., 2019b). it is very rarely possible to obtain early jurassic ages, and radiolarites of early jurassic age were only discovered in two sections, at angelokastron and vothiki (argolis), (chiari et al., 2013). numerous radiolarian studies have been carried out in ser­ bia during the last two decades (e.g. goričan et al., 1999; djerić et al., 2007, 2012; gawlick et al., 2009, 2016, 2018; vishnevskaya et al., 2009; chiari et al., 2011; bragin et al., 2011, 2019a, b) but a lot of the biostratigraphic age dating has still to be undertaken to solve the remaining open questions. the difficult reconstruction of the geodynamic history of the adriatic passive margin and the ophiolite belts in the dinarides age of the jurassic hemipelagic sediments from the ljubiš area (zlatibor mt., sw serbia) nikita bragin1* and nevenka djerić2 1 geological institute ras, pyzhevsky 7, 119017 moscow, russia; (*corresponding author: bragin.n@mail.ru) 2 university of belgrade, faculty of mining and geology, kamenička 6, 11 000 belgrade, serbia; (nevenka.djeric@rgf.bg.ac.rs) doi: 10.4154/gc.2020.11 abstract the type section of the ljubiš formation, (djokov potok, zlatibor area, western serbia) is characterized by abundant poorly-to-moderately preserved radiolarians. the lower part of the type section is characterized by middle jurassic (?bajocian to bathonian) radiolarian assemblages with japonocapsa fusiformis (yao), takemuraella weghae (grill & kozur), eoxitus hungaricus kozur, e. baloghi kozur, helvetocapsa matsuokai (sashida), quarkus japonicus (yao), hexasaturnalis suboblongus (yao), h. tetraspinus (yao). taking into account previous data from the upper part of the ljubiš formation, the age of the formation can be estimated to be in the interval from the ?bajocian to bathonian-oxfordian. the new biostratigraphic data clearly show the onset of tectonic motion in the middle jurassic, documented by the presence of mass transport deposits intercalated in the radiolarite successions. this suggests a middle jurassic onset of ophiolite obduction which triggered the rapid deepening of the adria margin, documented by the abrupt change from carbonate to radiolarite deposition. needs careful analysis of all sedimentary deposits, including their biostratigraphy, facies, history of deposition, and tectonic events. in recent work gawlick et al. (2017), sudar & gaw­ lick (2018) and gawlick & missoni (2019) propose a new stratigraphic scheme for the triassic and jurassic of the inner di­ narides. numerous stratigraphic series (formations) were ana­ lyzed: some of them were revised, others were established for the first time. radiolarite formations in this scheme are most com­ mon in the middle and upper jurassic deposits. biostratigraphic data of these numerous formations are variable. in some instances they are very comprehensive, while in the other cases they are scarce or rare. some formations still have only limited biostrati­ graphic control and their stratigraphic positions were determined by indirect methods. gawlick et al. (2017) recently proposed a late middle jurassic to late jurassic age for the ljubiš forma­ tion, but the dating was not precise due to poor preservation of the radiolarians. during the 2015 field season, we studied the reference sec­ tion of the ljubiš formation (sensu gawlick et al., 2017) in djokov potok, and present here the first biostratigraphic data from these sedimentary rocks based on radiolarians. 2. geological overview the research area is situated in sw serbia, in ljubiš village on the eastern flanks of mt. zlatibor. the wider area is characterized by a rather complicated structure. according to schmid et al. (2008), it comprises the adria-derived drina-ivanjica (diu) and east bosnian-durmitor units (ebdu), with the west vardar ophiolites superimposed on top, i.e. presently located between the diu to the northeast and the edbu to the southwest (fig.1). both adria-derived units (drina-ivanjica and east bosnian-dur­ mitor) being thrust by the ophiolitic mélange during the late ju­ rassic (schmid et al., 2008). the present-day position of the drina-ivanjica above the east bosnian-durmitor unit is a result of out-of-sequence thrusting during the cretaceous (schmid et article history: manuscript received january 24, 2020 revised manuscript accepted july 29, 2020 available online october 22, 2020 keywords: radiolaria, dinarides, jurassic, stratigraphy, serbia g eo lo gi a c ro at ic a geologia croatica 73/3144 figure 1. the main tectonic units of serbia and adjacent territories (modified after schmid et al., 2008). figure 2. a simplified geologic map of the zlatibor-zlatar area with the position of the djokov potok section (modified after djerić et al., 2012). g eologia c roatica bragin and djerić: age of the jurassic hemipelagic sediments from the ljubiš area (zlatibor mt., sw serbia) 145 al., 2008) or late jurassic (tithonian; gawlick & missoni, 2019). gawlick et al. (2017) note that in triassic-jurassic times these two units (drina–ivanjica and east-bosnian durmitor) were part of the same shelf – the drina–ivanjica unit (slightly metamorphosed) represents a more distal shelf area than the east bosnian-durmitor unit (unmetamorphosed). according to djerić et al. (2007), radiolarites of the djokov potok section, as a part of the triassic-jurassic sedimentary suc­ cession formed along the adriatic passive margin, belong to the east bosnian-durmitor unit (fig. 2). the east bosnian-durmitor unit was defined by dimitrijević (1974) and corresponds to the “zone serbe” of rampnoux (1970) and aubouin et al. (1970). according to schmid et al. (2008) the east bosnian durmitor unit comprises two sub-units, the more external durmitor sub-unit (monte negro) and the more internal lim sub-unit (sw serbia). the triassic of the durmitor sub­unit is characterized by thick carbonate plat­ form sediments (rampnoux, 1970; pantić & rampnoux, 1972), while the more internal lim sub-unit is characteri zed by a more distal slope or basinal facies represented by cherty lime­ stones (the “grivska formation”, dimitrijević & dimitrijević, 1991) and a late triassic reefal and slope facies (dimitrijević, 1997). recently, all grivska formation occur­ rences are attributed to the allochthonous and far­travelled nappe with a palaeogeographic derivation far to the east (gawlick et al., 2017). at the beginning of the jurassic, the carbonate plat­ forms in the inner dinarides were drowned and a relatively sud­ den deepening of the adriatic shelf in the middle jurassic re­ sulted in widespread deposition of radiolarites (djerić et al., 2012; vishnevskaya et al., 2009). all these sediments were overthrust by the ophiolitic mélange and overlying ophiolites in the late jurassic (fig. 2). in contrast to these interpretations gawlick et al. (2017) excluded the late triassic reefal and slope facies as remnants of an overthrust nappe. during the last few years investigations car­ ried on in sw serbia (gawlick et al., 2017 and references therein) have been focused on the lithoand microfacies analysis, and biostratigraphic analysis of the components of the mélanges. based on the data obtained, gawlick et al. (2017, p. 4) con­ cluded: “the ophiolite and distal continental margin nappes including different mélanges rest today as polyphase far travelled transported nappe stack on an parautochthonous triassic-jurassic sedimentary sequence that was palaeogeographically situated between the east bosnian durmitor unit and drina–ivanjica unit”. in the inner dinarides, besides the sub-ophiolitic mélange, these authors also distinguish different parautochthonous se­ quences below the overthrust units. according to gawlick & missoni (2019 and references therein) sedimentary mélanges derived from sedimentation processes in deep­water trench­like foreland basins in front of the propagating nappes triggered by ophiolite obduction. these deep­water basins were supplied by the erosional products of the advancing nappe stack and embed­ ded in a radiolarite bearing argillaceous matrix. according to these authors, the djokov potok locality in the ljubiš village is the type section of the newly established ljubiš formation (fig. 3). these jurassic radiolarites intercalated with calciturbidites deposited in a trench-like basin (ljubiš basin) outcrop in a tec­ tonic window below the overthrust allochthonous units (ophiolitic mélange and sirogojno mélange), and belong to the parautoch­ thonous sequences between the drina–ivanjica unit to the east and the east bosnian durmitor unit to the west (gawlick et al., 2017). 3. section description and biostratigraphy the studied section is located in donji ljubiš village and starts from the lower flow of djokov potok creek to the west and uphill. the coordinates of the starting point of the section are n 43˚ 37’ 14.0” e 19˚ 50’ 56.1”. we studied and sampled the lower part of this section up to the point n 43˚ 37’ 16.0” e 19˚ 50’ 54.5”. the underlying formation is not visible at the surface. a geological column of the section is shown in fig. 4. the section begins with a two­metre thick unit consisting of calcareous mass transport deposits and turbidites intercalated with dark­grey radiolarites (gawlick et al., 2017) (unit 1). five metres of dark greenishgrey thin­bedded radiolarites intercalated with greenish­grey cherty claystone follow (unit 2) (fig. 5a, b). the next unit in the column is a 0.5 m thick grey massive calcarenite (unit 3). further up in the column, there are dark greenish-grey thin-bedded ra­ diolarites intercalated with greenish­grey cherty mudstone. thin calcarenite beds appear 3 m above the base of this unit. the whole unit (unit 4) is 8 m thick. unit 5 comprises 1 m of a grey massive calcarenite (fig. 5c). the section ends with 12 m of dark green­ ish­grey thin­bedded radiolarites intercalated with greenish­grey cherty mudstones (unit 6) (fig. 5d). radiolarites of this formation are characterized by an abun­ dance of radiolarian tests, but they are generally strongly recrys­ tallized and very poorly preserved. sometimes the radiolarians cannot be extracted from the rock: they become partly or com­ pletely dissolved during the maceration process. radiolarites were sampled and processed by the traditional method. small (100 g) pieces of rocks were etched by diluted (5-10%) hydrofluo­ ric acid (hf) for 12 hours. then the residue was washed with wa­ ter and dried. figure 3. the main jurassic lithostratigraphic units of the inner dinarides (gawlick et al., 2017). g eo lo gi a c ro at ic a geologia croatica 73/3146 unit 4 is characterized by poorly preserved specimens. some of them can be identified to generic level or in open nomenclature (table 1, fig. 6, plate 1, figs. a-c, e-k). the fourth unit, consist­ ing of dark greenish-grey, thin-bedded radiolarite, contains the next datable samples: sample 15-10-7 contains the following radiolarian assem­ blage: japonocapsa fusiformis (yao) (= tricolocapsa fusiformis, in baumgartner et al., 1995a), eoxitus hungaricus kozur, helvetocapsa matsuokai (sashida), quarkus japonicus (yao) (= stichocapsa japonica, in baumgartner et al., 1995a), eucyrtidiellum sp. cf. e. unumaense s.l. (yao), quarticella sp., hsuum sp., parahsuum sp., parvimitrella sp. (plate 1, table 1). on the basis of the presence of japonocapsa fusiformis (yao), an early-middle bajocian to late bajocian-early bathonian (uazs 3-5; baumgartner et al., 1995b) age can be inferred. how­ ever, suzuki & gawlick (2009) found this species also in association with younger radiolarians in several samples indicat­ ing that this species may also be present in younger deposits – callovian and even in the lower oxfordian (gawlick, pers. comm.). other taxa have broad stratigraphic ranges: helvetocapsa matsuokai was found in the middle-late callovian (su­ zuki & gawlick, 2009), and quarticella sp. is present in the callovian (gawlick et al., 2009). therefore, we have to esti­ mate a wide stratigraphic range for this sample – bajocian to callovian. sample 15-10-8 is characterized by a poor and badly pre­ served radiolarian assemblage. the age could not be determined because it contains only campanomitra? sp. a sensu o’dogherty, goričan & gawlick, 2017 and praewilliriedellum sp. radiolarites from unit 6 are characterized by better preser­ vation of the radiolarians (table 1, fig. 6, plate 1, figs. d, l-p, plate 2). samples 15-10-10 and 15-10-11 were taken from the sixth unit (made up of dark greenish-grey thin-bedded radiolarites, with interlayers of greenish-grey cherty mudstones). sample 15-10-10 yields several radiolarian species with con­ current stratigraphic ranges that allow us to date them. the most important feature of sample 15-10-10 is the co-occurrence of hexa saturnalis suboblongus (yao) (= acanthocircus suboblongus, in baumgartner et al., 1995a) and h. tetraspinus (yao) which suggests the interval from uaz 3 to uaz 6 (early-middle bajocian to middle bathonian) (baumgartner et al., 1995b). additionally, the presence of takemuraella weghae (grill & kozur) and hsuum sp. cf. h. baloghi grill & kozur con­ firms the bajocian-bathonian age determination (grill & ko­ zur, 1986; o’dogherty et al., 2006; 2017). considering the stratigraphic position of sample 15-10-10 within the entire section (see fig. 4) and the age of sample 15-10-11 table 1. species occurrence list of radiolarians from the middle jurassic djokov potok section. samples radiolarian taxa 15-10-7 15-10-8 15-10-10 15-10-11 japonocapsa fusiformis (yao) r r eoxitus hungaricus kozur c parahsuum sp. r quarkus japonicus (yao) c helvetocapsa matsuokai (sashida) c eucyrtidiellum sp. cf. e. unumaense s.l. (yao) r quarticella sp. c parvimitrella sp. r campanomitra? sp. a sensu o’dogherty, goričan & gawlick, 2017 r praewilliriedellum sp. c c hsuum sp. cf. h. matsuokai isozaki & matsuda r praewilliriedellum convexum (yao) c parahsuum sp. cf. p. izeense (pessagno & whalen) c parahsuum sp. r takemuraella veghae (grill & kozur) r r hsuum sp. cf. h. baloghi grill & kozur c quarticella sp. d sensu o’dogherty, goričan & gawlick, 2017 r hexasaturnalis suboblongus (yao) r hexasaturnalis tetraspinus (yao) r transhsuum sp. r r c eoxitus baloghi kozur c parahsuum sp. cf. p. indomitum (pessagno & whalen) r mizukidella sp. r hsuum sp. r theocapsomella sp. r figure 4. a lithological column of the lower part of the djokov potok section (ljubiš formation). the numbers of units are shown to the left of the column. positions of samples with radiolarians are indicated on the right of the column by arrows. 1 – radiolarites and mudstones; 2 – limestones and calcarenites. g eologia c roatica bragin and djerić: age of the jurassic hemipelagic sediments from the ljubiš area (zlatibor mt., sw serbia) 147 discussed below, the age of this sample ranges from the bajocian to the bathonian (uazs 3-6). the bathonian age seems to be more likely due to previous studies (gawlick et al., 2017). sample 15-10-11 was taken from the uppermost layers of this unit. the following species were identified from the radiolarian association: takemuraella weghae (grill & kozur), eoxitus baloghi kozur, japonocapsa fusiformis (yao), pseudoristola sp. cf. p. durisaeptum (aita) (= amphipyndax durisaeptum, in baumgartner et al., 1995a), parahsuum sp. cf. p. indomitum (pessagno & whalen), mizukidella sp., hsuum sp., transhsuum sp., theocapsomella sp. due to the presence of takemuraella weghae the assemblage is compatible with uazs 3 to 6, covering the time span from the bajocian to the bathonian. as some taxa were determined in open nomenclature and their data adequacy is relatively low, we can conclude that the lower part of the ljubiš formation has a middle jurassic, ?bajo­ cian to bathonian age. 4. discussion the ljubiš formation was proposed by gawlick et al. (2017) as a possible age equivalent of the middle to upper jurassic (ba­ thonian-tithonian) gonje formation (vishnevskaya et al., 2009) developed in the western part of the dinaridic ophiolite belt (fig. 3). the gonje formation is represented by various co­ loured radiolarites with intercalated mass transport deposits and turbidites in the upper part and dated by radiolarians and fora­ minifers (radoićić et al., 2009). according to gawlick et al. (2017) the mass transport deposits in the upper part of the gonje formation (kimmeridgian-tithonian age) have a com­ pletely different component spectrum to that of the ljubiš forma­ tion. in contrast to the gonje formation the ljubis fm. contains late triassic lagoonal and back-reefal dachstein limestone and some condensed early and middle jurassic components from the overlying of the dachstein limestone in the lower part, and in the upper part additional late jurassic shallow-water compo­ nents; the gonje fm. contains various clasts, e.g. late jurassic shallow-water clasts; open-marine late triassic limestone clasts, various heavy minerals and others (gawlick et al., 2017). the ljubiš formation was dated at the type-locality only by the pres­ ence of the radiolarian specimen eucyrtidiellum sp. cf. e. unumaense (gawlick et al., 2017). also, bedded greenish-grey radiolarites with intercalated turbidites of the ljubiš formation are preserved below the overthrust ophiolitic mélange in the dou­ ble road curve south of ljubiš (between ljubiš and jasenovo). these radiolarites from the ophiolitic mélange, gawlick et al. (2016), were dated by a better preserved radiolarian assemblage (callovian to middle oxfordian age). gawlick et al. (2017) re­ ported a latest bajocian to middle oxfordian age from the ljubiš figure 5. outcrops of the ljubiš formation in djokov potok. a – grey bedded radiolarites intercalated with grey cherty mudstones, unit 2; b – detail of radiolaritemudstone intercalation, unit 2; c – grey massive calcarenite, unit 5, below are radiolarites of unit 4; d – bedded radiolarites of unit 6. g eo lo gi a c ro at ic a geologia croatica 73/3148 formation on the western slope of vis mountain. according to gawlick et al. (2017) the preserved part of the ljubiš basin represents a more proximal part of the basin and the thickness of this basin fill is at least 400 m. in the currently uninvestigated most proximal parts of this basin the authors expected a much thicker sequence (up to 1000m). it should be mentioned that in the type area, the underlying bositra limestones do not outcrop. also, it is important to note that turbiditic layers, common in the ljubiš formation, yield upper triassic to middle jurassic com­ ponents (gawlick et al., 2017): the triassic components were derived from the lagoonal dachstein carbonate platform, while the lower and middle jurassic clasts are represented by red nodular limestone and bositra-limestone. gawlick et al. (2017) supposed that this turbidite material was derived from the upper triassic-middle jurassic sedimentary succession of the diu, however, the krš gradac quarry contains only late triassic clasts from the fore­reef. on the basis of our new data the analyzed radiolarites (the lower part of ljubiš formation) were deposited in the time period of the bajocian to the bathonian. the ljubiš formation above our samples contains reworked middle jurassic bositra limestone clasts (gawlick et al., 2017), known mainly from the bajocianbathonian, so these radiolarites should be younger than the re­ worked clasts. anyway, the deposition of the ljubiš formation could have started earlier than previously thought – in the early bathonian or even in the late bajocian. further study of the biostratigraphy and detailed analysis of the sections would be needed to achieve a better understanding of the composition and nature of the ljubiš formation. 5. conclusions middle jurassic (bajocian-bathonian) radiolarian assemblages were discovered in radiolarites of the lower part of the ljubiš for­ mation in the type section in djokov potok (ljubiš village, sw serbia). the age of the samples cannot be assigned very precisely due to the poor preservation of the radiolarians. the whole strati­ graphic range of the ljubiš formation could range from the lower-middle bajocian to the oxfordian if we take into account previous bathonian-oxfordian radiolarian data from the upper part of the formation (gawlick et al., 2017). the newly deter­ mined biostratigraphic ages based on radiolarian faunas clearly show the onset of tectonic motion in the middle jurassic, docu­ mented by the deposition of mass transport deposits intercalated in thick radiolarite successions. this suggests the middle juras­ sic onset of ophiolite obduction which triggered the drag down of the adria margin documented by the abrupt change from car­ bonate to radiolarite deposition. acknowledgement this research was supported by the ministry of education sci­ ence and technological development of the republic of serbia, project no. 176015 and by the russian governmental program no 0135-2018-0033. the authors greatly appreciate the valuable comments given by hans-jürgen gawlick, renata jach and an anonymous reviewer and the help of john rogers who im­ proved the english language of the manuscript. lastly, we would like to pay our gratitude and our respects to our friend and col­ league, nataša gerzina. after many joint fieldtrips, nataša gerzina passed away in june 2019. the study would not have been possible without the extraordinary knowledge and collabo­ ration of the esteemed nataša gerzina. references aubouin, j., bonneau, m., celet, p., charvet, j., clement, b., degar­ din, j.m., dercourt, j., ferrière, j., fleury, j.j., guernet, c., mail­ lot, h., mania, j.h., mansy, j.l., terry, j., thiebault, p., tsoflias, p. & verrieuz, j.j. (1970): contribution à la géologie des hellénides: le gav­ rovo, le pinde et la zone ophiolitique subpélagonienne.– ann. soc. géol. nord, 90, 277–306. baumgartner, p.o., o’dogherty, l., goričan, š., dumitrica-jud, r., dumitrica, p., pillevuit, a., urquhart, e., matsuoka, a., danelian, t., bartolini, a., carter, e.s., de wever, p., kito, n., marcucci, m. & steiger, t.a. (1995a) radiolarian catalogue and systematics of middle jurassic to early cretaceous tethyan genera and species.– in: baumgartner, p.o., o’dogherty, l., goričan, š., urquhart, e., pillevuit, a. & de wever, p. (eds.): middle jurassic to lower cretaceous radiolaria of tethys: occurrences, systematics, biochronology. mémories de géolo gie, 23, 37–685. baumgartner, p.o., bartolini, a., carter, e.s., conti, m., cortese, g., danelian, t., de wever, p., dumitrica, p., dumitrica-jud, r., goričan, š., guex, j., hull, d., kito, n., marcucci, m., matsuoka, a., murchey, b., o’dogherty, l., savary, j., vishnevskaya, v., widz, d. & yao, a. (1995b): middle jurassic to early cretaceous radiolarian biochronology of tethys based on unitary associations.– in: baumgartner, figure 6. the stratigraphic ranges of selected radiolarian taxa and the stratigraphic position of the studied samples. dotted lines show the stratigraphic ranges of taxa determined in open nomenclature and taxa for which the stratigraphic range needs more detailed study. stratigraphic ranges were attributed according to baumgartner et al. (1995b) with additional data from suzuki & gawlick (2009) and gawlick et al. (2009). g eologia c roatica bragin and djerić: age of the jurassic hemipelagic sediments from the ljubiš area (zlatibor mt., sw serbia) 149 p.o., o’dogherty, l., goričan, š., urquhart, e., pillevuit, a. & de wever, p. (eds.): middle jurassic to lower cretaceous radiolaria of tethys: occurrences, systematics, biochronology.– mémories de géologie, 23, 1013–1048. bragin, n.y., bragina, l.g., djerić, n. & toljić, m. (2011): triassic and ju­ rassic radiolarians from sedimentary blocks of ophiolite mélange in the avala go­ ra area (belgrade surroundings, serbia).– stratigraphy and geological correlation, 19/6, 631–640. doi: 10.1134/s0869593811050030 bragin, n.y., bragina, l.g., djerić, n. & gerzina spajić, n. (2019a): late triassic radiolarians from the grivska formation.– geološki anali balkanskoga poluostrva, 80/1, 17–27. bragin, n.y., bragina, l.g., gerzina spajić, n., djerić, n. & schmid, s. (2019b): new radiolarian data from the jurassic ophiolitic mélange of avala moun­ tain (serbia, belgrade region).– swiss journal of geosciences, 112/1, 235–249. doi: 10.1007/s00015-018-0313-8 chiari, m., baumgartner, p., bernoulli, d., bortolotti, v., marcuc­ ci, m., photiades, a. & principi, g. (2013): late triassic, early and middle jurassic radiolaria from ferromanganese-chert “nodules” (angelokastron, argo­ lis, greece): evidence for prolonged radiolarite sedimentation in the maliac–vardar ocean.– facies, 59, 391–424. doi: 10.1007/s10347-012-0314-4 chiari, m., djerić, n., garfagnoli, f., hrvatović, h., krstić, m., levi, n., malasoma, a., marroni, m., menna, f., nirta, g., pandolfi, l., principi, g., saccani, e., stojadinović, u. & trivić, b. (2011): the geology of the zlatibor-maljen area (western serbia): a geotraverse across the ophiolites of the dinaric-hellenic collisional belt.– ofioliti, 36/2, 139–166. dimitrijević, m.d. (1974): the dinarides: a model based on “now global tecton­ ics”.– in: metallogeny and concepts of the geotectonic development of yugosla­ via, symposium, rgf, 141–178, beograd. dimitrijević, m.d. (1997): geology of yugoslavia.– geological institute gemini, belgrade, 187 p. dimitrijević, m.n. & dimitrijević, m.d. (1991): triassic carbonate platform of the drina-ivanjica element (dinarides).– acta geol. hung., 34, 15–44. djerić, n., gerzina, n. & schmid, m.s. (2007): age of the jurassic radiolarian chert formation from the zlatar mountain (sw serbia).– ofioliti, 32/2, 101–108. djerić, n., gerzina, n. & schmid, m.s. (2012): middle jurassic radiolarian as­ semblages from the sedimentary cover of the adriatic margin (zlatibor mountain, sw serbia).– bulletin de la société géologique de france, 183/4, 359–368. ferrière, j., chanier, f., baumgartner, p.o., dumitrica, p., caridroit, m., bout-roumazeilles, v., graveleau, f., danelian, t. & ven­ talon, s. (2015): the evolution of the triassic-jurassic maliac oceanic litho­ sphere: insidhts from the supra-ophiolitic series of othris (continental greece).– bulletin de la société géologique de france, 186/6, 399–411. doi: 10.2113/ gssgfbull.186.6.399 gawlick, h.-j., missoni, s., sudar, m.n., suzuki, h., mères, s., lein, r. & jovanović, d. (2018): the jurassic hallstatt mѐlange of the inner dinarides (sw serbia): implications for triassic-jurassic geodynamic and palaeogeograph­ ic reconstructions of the western tethyan realm.– neues jahrbuch für geologie und paläontologie abhandlungen, 288/1, 1–47. gawlick, h.-j., sudar, m.n., missoni, s., suzuki, h., lein, r. & jovanović, d. (2017): jurassic geodynamic history of the dinaridic ophiolote belt (innere dinarides, sw serbia).– journal of alpine geology, 55, 1–167. gawlick, h.-j., sudar, m., suzuki, h., djerić, n., missoni, s., lein, r. & jovanović, d. (2009): upper triassic and middle jurassic radiolarians from the ophiolitic melange of the dinaridic ophiolite belt, sw serbia.– neues jahr­ buch für geologie und paläontologie, 253/2–3, 293–311. doi: 10.1127/00777749/2009/0253-0293 gawlick, h.-j., missoni, s., suzuki, h., sudar, m., lein, r. & jovanović, d. (2016): triassic radiolarite and carbonate components from the jurassic ophi­ olitic mélange (dinaridic ophiolite belt).– swiss journal of geosciences, 109/3, 473–494. doi: 10.1007/s00015-016-0232-5 gawlick, h.-j. & missoni, s. (2019): middle-late jurassic sedimentary mélange formation related to ophiolite obduction in the alpine­carpathian­dinaridic moun­ tain range.– gondwana research, 74, 144–172. doi: 10.1016/j.gr.2019.03.003 goričan, š., karamata, s. & batoćanin-srećković, d. (1999): upper triassic (carnian–norian) radiolarians in cherts of sjenica (sw serbia) and the time span of the oceanic realm ancestor of the dinaridic ophiolite belt.– bulletin classe des sciences mathѐmatiques et naturelles sciences naturelles academie serbe des sciences et des arts, 39, 141–149. grill, j. & kozur, h. (1986): first evidence on the unuma echinatus radiolarian zone in the rudabánya mts (northern hungary).– geol. paläont. mitt. innsbruck, 13/11, 239–275. karamata, s. (2006): the geological development of the balkan peninsula related to the approach, collision and compression of gondwanan and eurasian units.– in: robertson, a. h.f. & mountrakis, d. (eds.): tectonic development of the eastern mediterranean region. the geological society, london, special publi­ cations, 155–178. doi: 10.1144/gsl.sp.2006.260.01.07 missoni, s., gawlick, h.-j., sudar, m.n., jovanović, d. & lein, r. (2012): onset and demise of the wetterstein carbonate platform in the mélange areas of the zlatibor mountain (sirogojno, sw serbia).– facies, 58, 95–111. doi: 10.1007/ s10347-011-0274-0 o’dogherty, l., bill, m., goričan, š., dumitrica, p. & masson, h. (2006): bathonian radiolarians from an ophiolitic mélange of the alpine tethys (gets nappe, swiss-french alps).– micropaleontology, 51, 425–485. doi: 10.2113/ gsmicropal.51.6.425 o’dogherty, l., goričan, š. & gawlick, h.-j. (2017): middle and late juras­ sic radiolarians from the neotethys suture in the eastern alps.– journal of paleon­ tology, 91/1, 25–72. doi: 10.1017/jpa.2016.96 obradović, j. & goričan, š. (1988): siliceous deposits in yugoslavia: occur­ rences, types, and ages.– in: hein, j.r. & obradović, j. (eds.): siliceous deposits of the tethys and pacific regions. springer, 51–64. doi: 10.1007/978-14612-3494-4_4 pantić, s. & ramphoux, j.-p. (1972): concerning the triassic in the yugoslavian inner dinarids (southern serbia, eastern montenegro): microfacies, microfaunas, an attempt to give a paleogeographic reconstitution.– mitt. ges. geol. bergbaust., 21, 311–326. radoičić, r., jovanović, d. & sudar, m. (2009): stratigraphy of the krš gra­ dac section (sw serbia).– geološki anali balkanskoga poluostrva, 70, 23–41. doi: 10.2298/gabp0970023r rampnoux, j.-p. (1970): regards sur les dinarides internes yougoslaves (serbiemonténégro oriental): stratigraphie, évolution paléogéographique, magmatisme.– bull. soc. géol. fr., 7, 12, 6, 948–966. doi: 10.2113/gssgfbull.s7-xii.6.948 schmid, s., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpinecarpathian­dinaridic orogenic system: correlation and evolution of tectonic units.– swiss journal of geosciences, 101, 139–183. doi: 10.1007/s00015-008-1247-3 sudar, m. & gawlick, h.-j. (2018): emendation of the grivska formation in their type area (dinaridic ophiolite belt, sw serbia).– geološki anali balkanskoga po­ luostrva, 79/1, 1–19. doi: 10.2298/gabp1879001s sudar, m., gawlick, h.-j., lein, r., missoni, s., kovács, s. & jovanović, d. (2013): depositional environment, age and facies of the middle triassic bulog and rid formations in the inner dinarides (zlatibor mountain, sw serbia): evi­ dence for the anisian break-up of the neotethys ocean.– neues jahrb. geol. paläontol. abh., 269, 291–320. doi: 10.1127/0077-7749/2013/0352 suzuki, h. & gawlick, h.-j. (2009): jurassic radiolarians from cherty limestones below the hallstatt salt mine (northern calcareous alps, austria).– neues jahrb. geol. paläontol. abh., 251, 155–197. doi: 10.1127/0077-7749/2009/0251-0155 vishnevskaya, v., djerić, n. & zakariadze, g.s. (2009): new data on mesozoic radiolaria of serbia and bosnia, and implications for the age and evolution of oceanic volcanic rocks in the central and northern balkans.– lithos, 108/1–4, 72–105. doi: 10.1016/j.lithos.2008.10.015 g eo lo gi a c ro at ic a geologia croatica 73/3150 plate 1. middle jurassic (bajocian to bathonian) radiolarians from the djokov potok section (samples 15-10-7, 15-10-8 and 15-10-10). a – japonocapsa fusiformis (yao); b – eoxitus hungaricus kozur; c – parahsuum sp.; d – parahsuum sp.; e – quarkus japonicus (yao); f – helvetocapsa matsuokai (sashida); g – eucyrtidiellum sp. cf. e. unumaense s.l. (yao); h – quarticella sp.; i – parvimitrella sp.; j – campanomitra? sp. a sensu o’dogherty, goričan & gawlick, 2017; k – praewilliriedellum sp.; l – hsuum sp. cf. h. matsuokai isozaki & matsuda; m – praewilliriedellum convexum (yao); n – parahsuum sp. cf. p. izeense (pessagno & whalen); o – takemuraella veghae (grill & kozur); p – praewilliriedellum convexum (yao). figs. a-c, e-i – sample 15-10-7; figs. j, k – sample 15-10-8; figs. d, l-p – sample 15-10-10. scale bar – 80 μm for figs. c, n and p; 50 μm for figs. a, b, d-m, o. g eologia c roatica bragin and djerić: age of the jurassic hemipelagic sediments from the ljubiš area (zlatibor mt., sw serbia) 151 plate 2. middle jurassic (bajocian to bathonian) radiolarians from the djokov potok section (samples 15-10-10 and 15-10-11). a – praewilliriedellum convexum (yao); b – parahsuum sp.; c – hsuum sp. cf. h. baloghi grill & kozur; d – quarticella sp. d sensu o’dogherty, goričan & gawlick, 2017: e – hexasaturnalis suboblongus (yao); f – hexasaturnalis tetraspinus (yao); g – transhsuum sp.; h – eoxitus baloghi kozur; i – takemuraella veghae (grill & kozur); j – pseudoristola sp. cf. p. durisaeptum (aita); k – parahsuum sp. cf. p. indomitum (pessagno & whalen); l – mizukidella sp.; m – hsuum sp.; n – theocapsomella sp.; o – japonocapsa fusiformis (yao). figs. a-f – sample 15-10-10: figs. g-o – sample 15-10-11. scale bar – f – 100 μm, other figures – 50 μm. 2019 | 72/1 | 19–42 | 12 figs. | 7 tabs. | 2 pls. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction sediments deposited in marginal marine environments, such as salt-marshes, lagoons, estuaries, deltas and coastal lakes exhibit distinctive micropalaeontological, geochemical and mineralogical compositions due to the variability of physical and chemical conditions (mackenzie et al., 1995; sen gupta, 1999; alve & murray, 1999; dix et al., 1999; taher, 2001; anadón et al., 2002; frontalini et al., 2011a). variability occurs as a consequence of the position of these environments at the land-sea transition. studies of marginal marine environments are necessary in palaeoenvironmental research, especially with regard to sea level changes (gehrels, 1994; edwards et al., 2004; marriner et al., 2014; müller-navara et al., 2017; benjamin et al., 2017; emmanouilidis et al., 2018). the specific geomorphological setting of the karstified eastern adriatic coast (pikelj & juračić, 2013), enabled development of unique marginal marine environments. veliko and malo jezero on mljet island are examples of submerged karst holocene foraminiferal and geochemical records in the coastal karst dolines of cres island, croatia dea brunović1, slobodan miko1, nikolina ilijanić1, zoran peh1, ozren hasan1, tena kolar2, martina šparica miko1 and ivan razum3 1 croatian geological survey, sachsova 2, 10000 zagreb, croatia; (dea.brunovic@hgi-cgs.hr) 2 university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, 10000 zagreb, croatia 3 croatian natural history museum, demetrova 1, 10000 zagreb, croatia doi: 10.4154/gc.2019.02 abstract numerous karst dolines have been formed along the croatian coast and many have been submerged during the late glacial and holocene sea level rise. the coastal area of cres island in the northern adriatic is a typical example of this geomorphological setting, where transitional forms from subaerial to submerged dolines are present. once dolines are formed they can accumulate soil, water and sediments due to their morphology. sediments are an especially valuable source of environmental data. this paper presents the results of the study of foraminiferal assemblages and sediment geochemistry, supplemented with grain-size and mineralogical data, from the marine ponds developed in the karst dolines on cres island. obtained data is correlated with the sediment core record from submerged dolines in the present-day embayments along the coastal zone of cres island. in total, 3 sediment cores were collected in the marine ponds marinska, arcij and podbrajde, while 2 longer sediment cores have been extracted from the jaz and sonte embayments. the marinska, arcij and podbrajde marine ponds have distinct geochemical and mineralogical sediment compositions, with monospecific foraminiferal assemblages and generally differ from each other. the common characteristics are their high n and p concentrations and the algal origin of organic matter. agglutinated foraminiferal taxa (haplophragmoides canariensis and trochammina inflata), typical for intertidal environments, are abundant in the brackish-water marinska pond, while stress-tolerant species ammonia tepida has been identified in the arcij marine pond. environmental conditions in the podbrajde marine pond did not facilitate the development of a rich foraminiferal fauna. results from the present-day marine ponds enabled recognition of similar environments in the sediment cores collected in the jaz and sonte embayments that were progressively inundated during the holocene sea level rise. a palaeo-marine pond existed in the sonte embayment until 6610 cal bp, when the sea flooded the investigated area. a marine pond in the jaz embayment was formed at 711 cal bp. low-diversity foraminiferal assemblages in these palaeo-ponds are similar to those recognized in the present-day arcij marine pond on cres island. however, differences in the geochemical composition of palaeo-marine ponds, in comparison to the present-day ponds, exist. they might be attributed to climate variability over time and variations in the geological setting of each environment. high mo concentrations and abundant organic matter content are the main sediment characteristics of the recognized palaeo-marine ponds in the jaz and sonte embayments. dolines with surface connection to the sea. in the literature, this type of environment is termed a marine lake (juračić et al., 1995; govorčin et al., 2001; vaniček et al., 2000; surić, 2002; surić, 2005; sondi & juračić, 2010; pikelj & juračić, 2013). marine lakes can also be found on other parts of the eastern adriatic coast, such as zmajevo oko near rogoznica and mir on dugi otok island. these shallow water environments have a subsurface connection to the sea allowing seepage through karstified bedrock (surić, 2002; surić, 2005; pikelj & juračić, 2013). since marine lakes are located in the coastal karst zone and the marine influence on their development is substantial, these environments can be considered as marginal marine types and they can preserve a record of the holocene sea level rise (wunsam et al., 1999; govorčin et al., 2001). other types of marginal marine environments (lagoons, estuaries and salt-marshes) have also been developed along the croatian coastline (pandža et al., 2007; pikelj & juračić, 2013). however, considerable work has yet to be conducted in terms of the description and characterization of the different types of tranarticle history: manuscript received july 04, 2018 revised manuscript accepted october 25, 2018 available online february 15, 2019 keywords: karst dolines, sediment cores, holocene, marginal marine environments, sea level change, foraminifera, organic carbon, trace elements, adriatic sea g eo lo gi a c ro at ic a geologia croatica 72/120 sitional environments present along the karstified eastern adriatic coast. the focus of many foraminiferal studies worldwide is the determination of species and their dependence on sea level and other environmental conditions in the salt-marshes (e.g., gehrels, 1994; hayward et al., 1999; edwards et al., 2004; serandrei barbero et al., 2004; kemp et al., 2013; stéphan et al., 2014; milker et al., 2015; müller-navara et al., 2017), estuaries and coastal lagoons (e.g., serandrei barbero et al., 1999; debenay et al., 2001; debenay & guillou, 2002; takata et al., 2006; jayalakshmy & rao, 2006; frontalini et al., 2011a; frontalini et al., 2011b; frontalini et al., 2013) and brackish-water coastal lakes (e.g., carboni et al., 2009). evidence for the survival of these typically marine organisms in inland saline lakes and freshwater lakes has also been postulated (boltovskoy & lena, 1971; cann & de dekker, 1981). physical and chemical water properties, sediment type, sediment geochemistry, tides, storms, winds, evaporation and distance from a direct marine influence are some of the main environmental parameters that have a crucial impact on the foraminiferal assemblages in the marginal marine environments (debenay et al., 2001; debenay & guillou, 2002; frontalini et al., 2011a). in general, it is considered that the fauna in these environments is less diverse and dominated by agglutinated species (debenay & guillou, 2002). recent foraminiferal studies along the eastern adriatic coast have been mostly restricted to investigation of species distribution (vidović, 2010; ćosović et al., 2011) and to the possible application of foraminifera as indicators of anthropogenic pollution (vidović et al., 2009; popadić et al., 2013; vidović et al., 2014). only a few studies have focused on the determination of fauna inhabiting marginal marine environments and their dependence on environmental conditions, as well as their application in palaeoenvironmental reconstructions. however, foraminiferal assemblages in marine lakes on the mljet island have been described in detail (vaniček et al., 2000; ćosović et al., 2016), while shaw et al. (2016) conducted a study of assemblages present in the jadrtovac and blace salt-marshes. results have produced valuable data about sea level variations in the investigated area and proven the utility of salt-marsh foraminifera in transfer functions. felja et al. (2015) determined a foraminiferal fauna in sediment cores from the mirna river valley in istria in order to decipher the palaeoenvironmental development of the valley. the geochemical composition of sediments reveals important environmental data. for example, the c/n ratio can be useful in the determination of organic matter provenance (meyers, 1994; meyers, 2003; lamb et al., 2006). nitrogen (n) and phosphorus (p) concentrations coupled with total organic carbon (toc) content are frequently used as indicators of nutrient availability and primary productivity (meyers, 1997; delaney, 1998; di et al., 2015). application of molybdenium (mo) as a proxy for redox conditions is also common (pedersen, 1989; crusius et al., 1996; calvert & pedersen, 1993; algeo & lyons, 2006; scholz et al., 2017). lead (pb) can be indicative of pollution (loring, 1978; helali et al., 2013) by industries and transport or its origin could be pb pellets shot during hunting practices in marsh environments (bianchi et al., 2011; migani et al., 2015; borghesi, 2016). examples of the previously conducted research of sediment geochemistry in the marginal marine environments along the croatian coast of the adriatic sea include studies of the veliko and malo jezero (cuculić et al., 2009; sondi et al., 2017), mir (mlakar et al., 2015) and zmajevo oko (mihelčić et al., 1996) marine lakes. furthermore, the geochemical composition of sediments from the shallow marine environments in bakar bay (cukrov et al., 2014) and makirina cove (šparica at al., 2005; miko et al., 2008; komar et al., 2015) was studied extensively. most of these studies focused on deciphering natural and anthropogenic metal enrichment and geochemistry was not used in order to reconstruct palaeoenvironments. our study offers a new insight into foraminiferal assemblages and sediment geochemistry in the marine ponds along the coastline of cres island. these environments have been formed in the karst dolines and should be considered as marginal marine environments due to their proximity to the sea and marine influence through karst. the main aim was to document typical foraminiferal species and their distribution in these unique water bodies since such studies are lacking along the eastern adriatic coast. special emphasis was on the determination of the linkages between foraminiferal assemblages and established environmental conditions manifested in the physical and chemical water properties and geochemical, mineralogical and sedimentological properties of the sediment. a further aim was to characterize environments in the jaz and sonte embayments, similar to those in the present-day marine ponds on cres island, using extracted sediment cores. obtained results would be indicative of the timing of the existence of holocene palaeo-marine ponds in these presently submerged karst dolines. we hypothesize that presentday marine ponds on cres island represent modern analogs of submerged holocene palaeo-marine ponds in the jaz and sonte embayments. 2. study area the investigated environments are located along the southwestern coastline of cres island, in the northern part of the adriatic sea in the kvarner region (fig. 1). this region is characterized by nw-se elongated islands (cres, lošinj, krk, rab, pag), with bays and channels (rijeka bay, kvarnerić bay, kvarner bay, vinodol-velebit channel, lošinj channel) located between the vinodol-velebit coastline and the istrian peninsula. final formation of the steep and rocky eastern adriatic coast occurred during the late glacial and holocene periods when sea flooded preexisting folded, faulted and karstified relief. anticlines became island chains while synclines became bays and channels (benac & juračić, 1998; juračić et al., 1999; kelletat, 2005; pikelj & juračić, 2013). the mesozoic carbonate rocks and their geological setting on cres island have been a target of many detailed studies (mamužić, 1968; magaš, 1968; husinec et al., 2000; korbar et al., 2001; korbar & husinec, 2003; fuček et al., 2012; fuček et al., 2014). limestones and dolomites of cretaceous age are predominant sedimentary rock formations. the oldest deposits have been formed during the lower cretaceous. younger palaeogene strata (foraminiferal limestones and flysch) are sporadically present in the northern part of cres island (fuček et al., 2014). quaternary sediments are rather scarce and present in the form of terra rossa outcrops, alluvial deposits and colluvial deposits on the slopes (magaš, 1968; benac & durn, 1997). subaerial exposure of cretaceous deposits enabled the formation of numerous karst dolines on cres island, especially in its southwestern part. dolines are enclosed karst depressions with variable depth and dimensions (ford & williams, 1989). it g eologia c roatica brunović et al.: holocene foraminiferal and geochemical records in the coastal karst dolines of cres island, croatia 21 is considered that post-miocene karstification in the mediterranean occurred in tectonically susceptible areas during periods of sea level lowstands. the most prominent and best preserved evidence of karstification developed during the most recent sea level lowstand (surić, 2005; mocochain et al., 2009; pikelj & juračić, 2013). the marinska, arcij and podbrajde marine ponds investigated in this study have variable depths, sill elevations separating the pond from the direct marine influence, distances to the sea and size (tab. 1). they have been developed in the karst dolines within two lithostratigraphic units (fig. 1), which are composed of alternations of dolomites and shallow marine limestones assigned to the upper albian-lower cenomanian boundary (sis unit) and cenomanian pelagic limestones (belej unit) (fuček et al., 2014). the karstic nature of cres island enables sea-water seepage through the karstified sill separating the ponds from the sea. dip directions trend towards the northeast (fuček et al., 2014) which possibly additionally facilitates this seepage through developed layering, underground fissures and conduits. the study area is microtidal, as recorded on the nearby tide gauge on lošinj island (http://tides.mobilegeographics.com/locations/3554.html). the present-day climate on cres island is considered to be temperate and humid with hot summers, while at the highest elevations summers are warm (šegota & filipčić, 2003). meteorological measurements between 1971-2000 at the nearby mefigure 1. map of the investigated area. a) overview, b) kvarner region and istrian peninsula, c) geological map of cres island and lošinj island (modified from fuček et al., 2014) and a bathymetry map of the lošinj channel with core locations. lithostratigraphic units shown on the map: cr-upper hauterivian to barremian cres limestones, dolomites, stromatolites, breccias and emerged surface alterations; kaaptian kanfanar limestones; poupper aptianlower albian porozina breccia and limestones; cnalbian crna limestones with emersion breccias; hrupper albian hrasta dolomites; sisupper albian-lower cenomanian alteration of sis dolomites and limestones with relict stromatolites, breccia and bauxite infillings; vrlower cenomanian vrana limestones; belower to middle cenomanian belej pelagic limestones; nicenomanian niska limestones; sdupper cenomanian to turonian sveti duh pelagic limestones; ghturonian to coniacian gornji humac limestones (fuček et al., 2014). table 1. main characteristics of the investigated environments and collected sediment cores. core location environment core core length (cm) depth at the coring location (m) the lowest sill elevation (m) distance to the sea (m) area (km2) jaz embayment lk-2 150 0.29 -0.5 — 0.029 sonte embayment lk-3 371 5 -3 — 0.23 marinska marine pond lk-5 35.5 0.15 1.1 50 0.005 arcij marine pond lk-6 46.5 0.3 0.3 92 0.018 podbrajde marine pond lk-7 34 0.15 0.7 136 0.03 g eo lo gi a c ro at ic a geologia croatica 72/122 teorological station in mali lošinj on the lošinj island indicate a mean summer air temperature of 23.1⁰c, with a maximum of 37.4⁰c occurring in august. during the winter, the temperature decreases significantly and mean air temperature reaches 8.3⁰c. the lowest measured air temperature in mali lošinj was –4.4⁰c (zaninović, 2008). relatively high amounts of rainfall have been recorded in the area, with mean annual precipitation of approximately 930.5 mm and the highest precipitation rates in the autumn (gajić-čapka et al., 2008). the human presence on cres island is documented by numerous archaeological sites (regan & nadilo, 2010; doneus et al., 2017). the channel that separates islands of cres and lošinj in the osor village has been dug artificially and today has a strong impact on water circulation in the lošinj channel, with currents causing deepening of the area south of osor (doneus et al., 2017). 3. materials and methods short sediment cores (up to 45.5 cm long) were collected in the marinska, arcij and podbrajde shallow marine ponds, by inserting a plastic pipe by hand into the sediment. sampling was conducted in september 2015. in total, 3 cores were extracted (lk-5, lk-6 and lk-7) and subsampled in 1 cm sections in the field using the core extruder (tab. 1). longer sediment cores (up to 371 cm long) from the jaz and sonte embayments were collected using a piston corer and coring platform in april 2014 (tab. 1). detailed subsampling of piston cores lk-2 and lk-3 was conducted after splitting the cores lengthwise. additionally, physical and chemical water parameters such as conductivity, temperature, ph and dissolved oxygen content were determined at each coring location using a portable multiparameter multi 3430 wtw probe. five mollusc samples from sediment cores lk-2 and lk-3 were dated by radiocarbon dating method (ams 14c) in order to establish core chronology and to determine the timing of palaeoenvironmental changes in the present-day jaz and sonte embayments. analyses have been conducted at beta analytics laboratory in usa. the radiocarbon data was corrected for the marine reservoir effect determined for the adriatic sea (faivre et al., 2015). grain-size was measured using a laser diffractometer shimadzu sald-2300. selected samples were treated with 30% hydrogen peroxide (h2o2) in order to remove organic matter. afterwards, samples were centrifuged, decanted and resuspended in distilled water prior to the analysis. in total, grain-size was determined on 6 samples from sediment cores lk-5 and lk-7, 4 samples from core lk-6, while 25 and 73 samples were analysed from sediment cores lk-2 and lk-3, respectively. statistical analysis of the grain-size results was conducted using the gradistat software (blott & pye, 2001) and sediments were classified according to folk & ward (1957). the bulk mineralogical composition of selected samples, as well as their clay mineralogy, was determined using a panalytical x’pert powder x-ray diffractometer. for the measurements, the diffractometer was set at 45 kv and 40 ma, with a step size of 0.02⁰ 2ө. different phases present in the samples were identified following moore & reynolds (1997). the clay fraction was analysed by mounting oriented aggregates on glass slides, after the removal of carbonates (where needed), using a buffered sodium acetate (naoac) solution. oriented samples were scanned, air-dried, ethylene-glycolated and analysed after being heated to 400°c and 550°c. core tops (1 cm thick) of the short sediment cores from marine ponds (lk-5, lk-6 and lk-7) were used for micropalaeontological analysis. samples were treated with rose bengal stain and 70% ethanol in the field and left for 14 days before being washed, following the procedure described by the fobimo group (schönfeld et al., 2012). piston cores lk-2 and lk-3 from the jaz and sonte embayments were analysed in more detail. foraminiferal analysis on these cores focused on the first cm of each core and intervals where geochemical, sedimentological and mineralogical data indicated significant shifts. these samples were not treated with rose bengal stain. for determination of the total foraminiferal assemblages (stained+empty tests) selected sediment samples were washed over a 63 µm sieve in the laboratory in order to remove silt and clay particles. according to schönfeld et al. (2012) >63 µm fraction is appropriate for foraminiferal analyses in palaeoenvironmental studies. each sample was divided by microsplitter and approximately 300 specimens were picked. in the samples where the total number of foraminifera specimens was less than 300, the whole sample was examined and counted. genera and species were recognized following the available literature and classifications by cimerman & langer (1991), sgarrella & moncharmont zei (1993) and loeblich & tappan (1987). calculation of the species richness, shannon-wiener index, fisher α index, dominance, evenness and equitability was conducted using the past software (hammer et al., 2001). cluster analysis of the total foraminiferal assemblages was performed using statistica 10 software with ward’s method and euclidean distances (statsoft, 2011). scanning electron microscope (sem) images of the common agglutinated and calcareous taxa observed in the samples were obtained using the jeol 35 cf scanning electron microscope, while the chemical composition of their tests was determined using the energy dispersive spectroscopy (eds-oxford x-act) and inca detection unit. analyses of the total organic (toc) and inorganic carbon (tic) and total nitrogen (n) were performed on 134 samples on a thermo fisher scientific flash 2000 nc analyzer. before analysis, the samples were freeze-dried, finely ground and treated with hydrochloric acid (hcl) for toc measurements (tung & tanner, 2003). calculation of tic is based on the difference between total carbon (tc) (untreated samples) and toc (samples treated with hcl). c/n ratio was calculated from toc and n measurements. elemental analysis was carried out on ground samples using inductively coupled plasma-mass spectrometry (icp-ms) in the acme laboratory, canada. geochemical data was analysed using multivariate statistical techniques. discriminant function analysis (dfa) included a selection of geochemical compositions (toc, tic, n, ca, mg, fe, k, al, p, s, cu, pb and mo) and a single ratio (c/n). results of the geochemical analysis represent a typical example of compositional data (coda) where correlations between relative elemental abundances may not be unequivocal in the absence of any other information or assumptions (lovell et al., 2015). a detailed description of coda analysis is reported elsewhere (peh & kovačević galović, 2014; peh & kovačević galović, 2016; galović & peh, 2016; šorša et al., 2018), with sample references to the original explanations from the research group on coda analysis (girona). discriminant function analysis (dfa) is a traditional multivariate statistical technique which is particularly useful in building the predictive model for the twoor multiple-group discrimination based on the suite of independent (predictor) variables. it g eologia c roatica brunović et al.: holocene foraminiferal and geochemical records in the coastal karst dolines of cres island, croatia 23 is commonly exercised in geoand environmental sciences when geological logic calls for the use of some autonomous criterion with regards to the variables in the analysed dataset, such as, in this case, the multi-proxy sediment core data analysis. objectives and principles of dfa are described comprehensively in many statistical textbooks (e.g., davis, 1973; davis, 1986; dillon & goldstein, 1984; rock, 1988; reimann et al., 2008). geochemical data were processed using the statistical software package of statistica 10 (statsoft, 2011) in the spirit of the coda analysis. 4. results 4.1. physical and chemical water parameters the investigated environments showed variability of the measured physical and chemical water parameters. table 2. shows conductivity (ec), ph, temperature (t) and dissolved oxygen (o2) concentrations. the ec measurements reveal significant differences, with the lowest ec values in the marinska marine pond (11.1 ms/cm) and the highest in the podbrajde marine pond (56.8 ms/ cm). the ph ranged from 8.24 (sonte embayment) to 9.07 (podbrajde marine pond). measured o2 concentrations varied from 9.11 mg/l in the sonte embayment up to 15.22 mg/l in the arcij marine pond. the highest temperature of 28.1⁰c was determined in the marinska pond. 4.2. sediment core analysis since the cores from marine ponds (lk-5, lk-6 and lk-7) are short (up to 45.5 cm) and analysis of the foraminiferal assemblages focused only on the core tops, we did not section them into distinct units (figs. 2 to 4). based on the sediment characteristics such as grain-size, toc, tic and n content, and the geochemistry of selected major and trace elements several units were diftable 2. measured water parameters in the investigated environments. core location core date of measurement ec (ms/cm) ph o2 (mg/l) temperature (⁰c) jaz lk-2 09/09/2015 56 8.39 13.33 23 sonte lk-3 09/09/2015 55.5 8.24 9.11 21.9 marinska lk-5 10/09/2015 11.1 8.36 15.12 28.1 arcij lk-6 10/09/2015 49.1 8.75 15.22 22.7 podbrajde lk-7 09/09/2015 56.8 9.07 14.73 23.9 figure 2. downcore variations of sedimentological and geochemical parameters in the sediment core lk-5 collected in the marinska marine pond. figure 3. downcore variations of sedimentological and geochemical parameters in the sediment core lk-6 collected in the arcij marine pond. g eo lo gi a c ro at ic a geologia croatica 72/124 ferentiated in the longer sediment cores lk-2 and lk-3 from the jaz and sonte embayments, respectively (figs. 5 and 6). in the lk-2 core two different units were recognized: 1. unit lk-2-1: 150–60 cm 2. unit lk-2-2: 60–0 cm the lk-3 core can be divided into four distinct units: 1. unit lk-3-1: 371–330 cm 2. unit lk-3-2: 330–260 cm 3. unit lk-3-3: 260–50 cm 4. unit lk-3-4: 50–0 cm the main features of the differentiated units are emphasized below. 4.2.1. core chronology the radiocarbon data obtained from the macrofossils of the piston cores lk-2 and lk-3 is shown in table 3. the sediment sequence in both cores is of holocene age and spans >6610 years in core lk-3 and >711 years in core lk-2. age reversal has been found in sediment core lk-3, with the result at the core depth of 354 cm being younger than the samples at 252 cm and 217 cm. due to the fact that results at 252 and 217 cm have been obtained on single mollusc shells each and the result at 354 cm has been obtained on mixed shells of gastropods and bivalves, the former are thought to be more reliable. therefore, the result at 354 cm has been discarded (tab. 3). 4.2.2. grain size analysis grain-size analysis on 110 samples from all sediment cores revealed variations in the grain-size both between cores and within particular cores (figs. 2 to 6, tab. 4). core tops are predominantly composed of coarse silt to medium sand. in most cores grain-size slightly decreases downwards with the general predominance of silty material (figs. 2 to 6). the highest sand abundance has been measured in the core lk-5 (<75%). generally, a significant amount of silty material (25-85%) has also been deposited, while the clay fraction (0-9%) is subordinate. core lk-6 is predominantly composed of silt (8088%). core lk-7 also shows a predominance of silty material (70-78%), while the sand (8-20%) and clay (11-14%) fractions are less abundant. samples from the sediment cores lk-2 and lk-3 have the highest silt content, 41-88% and 40-91%, respectively. figure 4. downcore variations of sedimentological and geochemical parameters in the sediment core lk-7 collected in the podbrajde marine pond. figure 5. downcore variations of sedimentological and geochemical parameters in the sediment core lk-2 collected in the jaz embayment. g eologia c roatica brunović et al.: holocene foraminiferal and geochemical records in the coastal karst dolines of cres island, croatia 25 4.2.3. mineralogical analysis bulk mineralogical analysis of sediment core lk-5 indicates the predominance of calcite and quartz, while aragonite is also abundant. halite, mg calcite, aragonite, gypsum, quartz, muscovite/ illite and pyrite are present in sediment core lk-6. sediment core lk-7 is characterized by the occurrence of halite, quartz, muscovite/illite and calcite. in the sediment cores lk-2 and lk3, quartz is the dominant mineral phase, while the calcite presence is variable downcore. in the basal part of the lk-2 core quartz, muscovite/illite and kaolinite are abundant (unit lk-2-1). the upper part of the lk-2 core (unit lk-2-2) is characterized by calcite, mg-calcite, aragonite and halite. muscovite/illite and plagioclase are present throughout the lk-2 core. the lowermost part of the core lk-3 (unit lk-3-1) shows the presence of quartz, muscovite/illite, chlorite and kaolinite. calcite and mg-calcite predominate in the upper part of the core (units lk-3-2, lk-3-3 and lk-3-4). aragonite, dolomite, halite, plagioclase, muscovite/ illite and kaolinite are less abundant. the presence of halite in all samples is a consequence of its crystallization from the pore water after sediment drying. the same clay minerals (chlorite, illite and kaolinite) characterize all the analysed cores. the only exception is the presence of mg clay mineral sepiolite in the sediment core lk-5. 4.2.4. foraminiferal analysis overall, 87 different species were identified in the total foraminiferal assemblages (all cores). samples from cores lk-5, lk-6 and lk-7 were less diverse and encompass 13 species. in the samples from the sediment cores lk-2 and lk-3, 81 foraminiferal species were determined. one sample (lk-2-1, 67-68 cm) did not contain foraminifera, while in the samples from the basal part of lk-3 core (unit lk-3-1) and from lk-7 core foraminifera specimens were scarce and poorly preserved. the first cm of sediment core lk-5 includes only agglutinated taxa. no live specimens were recognized. dominant species are haplophragmoides canariensis (48%) and trochammina inflata (41%), while miliammina fusca and entzia macrescens are significantly less abundant (tab. 5; plate 1). in the lk-6 core top sample ammonia tepida specimens predominate (97%) (tab. 5; plate 1). in total, 37 stained specimens were recognized in this sample, while 6 stained specimens showed morphological abnormalities, including enlarged chambers and twisted coiling (plate 1). only 7 foraminifera specimens were discovered in the first cm of core lk-7 collected in the podbrajde marine pond (tab. 5). the lower part of the lk-2 core was barren of foraminifera (unit lk-2-1), while the gradual occurrence of foraminifera specimens was observed at core depth of 62–63 cm. foraminifera figure 6. downcore variations of sedimentological and geochemical parameters in the sediment core lk-3 collected in the sonte embayment. table 3. ams 14c dating results of mollusc shells in sediment cores lk-2 and lk-3. the last result (marked with asterisk) has been discarded. core depth (cm) sample id material dated conventional radiocarbon age (14c bp) probability (%) calibrated age (cal bp) lk-2 42 beta – 387747 bivalve shell 1000 ± 30 50 506–571 44.7 580–651 lk-2 58 beta – 387748 bivalve shell 1200 ± 30 88 641–782 6.9 564–590 lk-3 94 beta – 387749 gastropod shell 2510 ± 30 95 1892–2148 lk-3 217 beta – 387750 bivalve shell 5550 ± 30 95 5713–5940 lk-3 252 beta – 387751 bivalve shell 6260 ± 30 95 6483–6737 lk-3* 354 beta – 387752 bivalve and gastropod shell 4000 ± 30 95 3693–3976 g eo lo gi a c ro at ic a geologia croatica 72/126 table 4. statistical parameters for the physicochemical characterisation of sediment cores. lk-5 lk-6 lk-7 lk-2-1 lk-2-2 lk-3-1 lk-3-2 lk-3-3 lk-3-4 ca (%) mean 23.27 12.52 4.72 1.33 8.82 6.19 7.65 19.54 23.73 sd 6.85 6.65 2.39 3.03 2.27 1.90 2.02 2.26 2.36 min 10.53 5.83 0.56 0.31 3.55 4.85 5.35 11.97 21.46 max 29.77 21.38 7.88 10.93 11.12 7.53 9.15 22.40 28.67 mg (%) mean 0.91 1.28 1.06 0.64 0.78 0.91 1.20 1.08 1.05 sd 0.06 0.19 0.29 0.09 0.16 0.08 0.05 0.09 0.07 min 0.81 1.09 0.68 0.46 0.63 0.85 1.17 0.92 0.92 max 1.02 1.68 1.50 0.82 1.05 0.97 1.26 1.26 1.18 fe (%) mean 0.93 1.67 2.77 3.65 2.63 2.48 1.83 1.65 1.20 sd 0.31 0.87 1.09 0.73 0.74 0.05 0.10 0.39 0.21 min 0.63 0.66 1.38 2.28 1.92 2.44 1.73 1.24 0.79 max 1.52 3.25 4.57 5.22 3.89 2.51 1.92 2.89 1.43 k (%) mean 0.51 0.59 1.24 1.57 0.99 1.37 0.91 0.65 0.50 sd 0.17 0.24 0.35 0.26 0.27 0.12 0.06 0.16 0.10 min 0.22 0.33 0.60 0.93 0.71 1.28 0.86 0.51 0.31 max 0.75 1.02 1.58 1.96 1.48 1.45 0.98 1.12 0.62 al (%) mean 2.05 2.21 4.97 6.84 4.27 6.21 4.14 2.86 2.03 sd 0.69 1.05 1.79 1.29 1.24 0.12 0.44 0.84 0.44 min 0.80 0.98 1.83 4.21 3.03 6.12 3.73 2.05 1.19 max 3.07 4.13 7.26 9.25 6.27 6.29 4.61 5.21 2.59 p (%) mean 0.06 0.04 0.07 0.03 0.02 0.03 0.03 0.01 0.01 sd 0.03 0.01 0.01 0.00 0.00 0.01 0.00 0.00 0.00 min 0.04 0.02 0.06 0.02 0.01 0.02 0.02 0.01 0.01 max 0.11 0.05 0.09 0.04 0.03 0.04 0.03 0.02 0.01 s (%) mean 0.70 2.87 1.06 0.32 1.69 1.85 2.20 1.36 0.85 sd 0.63 1.10 0.82 0.36 0.63 0.78 0.20 0.45 0.25 min 0.20 1.40 0.10 0.10 1.00 1.30 2.00 0.90 0.30 max 1.80 4.30 2.40 1.40 3.00 2.40 2.40 2.50 1.10 cu (mg/kg) mean 11.15 14.53 22.37 25.41 14.22 24.25 17.43 9.73 7.78 sd 2.44 6.42 2.74 4.65 3.37 2.33 1.85 3.30 1.35 min 8.70 5.70 17.90 16.10 9.90 22.60 15.60 6.00 5.30 max 15.80 22.30 26.60 33.20 20.80 25.90 19.30 19.40 9.60 pb (mg/kg) mean 22.61 23.41 57.36 28.66 25.63 24.90 16.00 10.81 10.98 sd 8.82 15.15 21.71 4.18 6.53 2.69 1.06 2.60 0.46 min 13.60 5.80 30.40 19.10 16.10 23.00 15.20 7.90 10.20 max 39.10 52.10 86.80 35.00 42.00 26.80 17.20 19.20 11.60 mo (mg/kg) mean 0.60 11.05 1.76 1.43 16.48 20.85 42.67 23.15 16.12 sd 0.66 4.74 1.18 0.76 7.13 8.27 2.20 4.98 8.62 min 0.10 4.60 0.60 0.60 7.10 15.00 41.30 15.30 0.70 max 1.90 18.60 4.70 3.60 33.10 26.70 45.20 38.60 26.60 toc (%) mean 5.40 9.58 6.24 0.50 2.14 6.00 13.34 2.51 1.38 sd 7.78 5.49 6.22 0.25 0.59 3.54 3.62 1.26 0.41 min 0.65 2.76 0.31 0.20 1.17 2.26 8.44 1.18 0.61 max 22.38 17.72 15.42 1.06 3.28 11.35 21.42 5.22 1.81 tic (%) mean 8.24 7.30 2.19 0.36 2.77 1.54 2.48 5.62 7.42 sd 2.02 3.79 1.08 1.01 0.58 0.85 2.12 1.02 0.64 min 3.07 3.03 0.74 bdl 1.30 0.55 0.05 3.23 6.76 max 10.34 11.80 4.16 3.56 3.30 2.81 8.52 7.00 8.57 n (%) mean 0.77 1.39 0.97 0.04 0.16 0.32 0.62 0.18 0.14 sd 0.96 0.49 1.02 0.01 0.06 0.18 0.14 0.06 0.04 min 0.12 0.90 0.07 0.02 0.08 0.13 0.41 0.10 0.07 max 2.57 2.13 2.60 0.06 0.29 0.61 0.92 0.30 0.18 c/n mean 6.22 6.49 6.93 12.77 13.20 18.70 21.50 13.74 9.86 sd 2.01 2.07 1.64 2.67 0.85 1.23 2.97 2.48 1.41 min 3.49 3.04 4.14 9.46 11.30 17.35 14.74 10.66 7.65 max 8.78 9.38 9.04 17.25 14.28 20.36 26.17 21.69 13.41 sand (%) mean 39.26 9.00 12.14 16.25 22.95 11.82 30.92 28.68 40.75 sd 27.53 6.63 4.41 14.41 17.57 12.96 15.78 12.53 9.89 min 15.16 0.06 8.25 0.00 3.25 0.02 5.94 2.18 25.53 max 74.67 14.77 19.53 30.22 55.76 29.91 56.13 50.35 59.45 silt (%) mean 56.74 83.82 75.07 70.43 70.67 77.12 63.52 65.87 55.92 sd 25.05 3.59 3.21 10.53 15.63 8.26 13.54 10.93 8.75 min 25.33 80.18 69.78 61.12 40.81 64.42 42.71 46.76 39.70 max 84.84 88.37 78.35 86.62 88.23 84.25 84.10 90.81 69.93 clay (%) mean 4.00 7.18 12.79 13.32 6.39 11.07 5.56 5.45 3.33 sd 4.40 3.11 1.28 8.10 2.87 5.28 2.75 2.22 1.47 min 0.00 4.90 10.68 7.37 3.20 5.67 1.17 1.94 0.85 max 8.70 11.57 14.17 36.46 12.27 16.79 10.80 11.55 5.40 g eologia c roatica brunović et al.: holocene foraminiferal and geochemical records in the coastal karst dolines of cres island, croatia 27 abundances significantly increased at 58–59 cm (unit lk-2-2), with the predominance of a. tepida (39%) (tab. 5). in the surface sample from this core different ammonia species predominate (up to 51%), while elphidium margaritaceum, bolivina striatula, haynesina depressula and elphidium translucens are less abundant (tab. 5, plate 2). samples from sediment core lk-3 also indicate the transition from intervals barren of foraminifera (unit lk-3-1) to their significant diversification (unit lk-3-4) (tab. 5). the predominance of a. tepida (6–46%) and cribroelphidium gerthi (0–21%) has been observed in all samples from the basal part of the core (unit lk-3-2) (tab. 5). miliolids (quinqueloculina parvula and figure 7. cluster dendrogram developed based on the foraminiferal analysis results using ward’s method and euclidean distances. table 5. the relative abundances of the foraminiferal species in sediment cores lk-5, lk-6, lk-7, lk-2 and lk-3. sample from the lk-2 core interval 62–63 cm corresponds to unit lk-2-1, while samples 0–1 cm and 58–59 cm correspond to unit lk-2-2. the lk-3 core samples belong to the following units: 349–350 cm, 340–342 cm – unit lk-3-1; 275–277 cm – unit lk-3-2; 243–245 cm and 230–232 cm – unit lk-3-3; 0–1 cm – unit lk-3-4. foraminifera (species) lk-5 lk-6 lk-7 lk-2 lk-3 0–1 0–1 0–1 0–1 58–59 62–63 0–1 230–232 243–245 275–277 340–342 349–350 adelosina carinata-striata 0.0 0.0 0.0 0.4 0.0 0.0 0.4 1.2 2.5 0.3 0.0 0.0 adelosina cliarensis 0.0 0.0 0.0 0.0 0.0 0.0 0.4 1.8 0.0 0.0 0.0 0.0 adelosina elegans 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.4 0.0 adelosina mediterranensis 0.0 0.0 0.0 0.0 0.0 0.0 0.7 0.0 0.0 0.0 0.0 0.0 ammonia sp. 0.0 0.0 14.3 12.4 1.0 4.0 0.0 0.6 8.8 1.2 0.0 0.0 ammonia beccarii 0.0 0.3 0.0 0.0 0.0 0.0 0.0 3.9 0.4 6.7 6.1 6.3 ammonia parkinsoniana 0.0 1.7 0.0 15.7 8.2 4.0 0.7 0.3 3.2 3.9 0.0 12.5 ammonia tepida 0.0 96.6 14.3 22.6 61.6 68.0 4.7 28.4 27.4 46.4 23.1 43.8 asterigerinata adriatica 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.5 4.4 12.5 asterigerinata mamilla 0.0 0.0 0.0 2.2 0.3 0.0 9.4 2.1 1.1 0.0 0.0 0.0 aubignyna perlucida 0.0 0.0 0.0 0.4 2.0 0.0 0.7 0.3 0.4 0.3 0.4 0.0 bolivina sp.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.9 0.0 0.0 0.0 0.0 bolivina sp.2 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.0 0.0 bolivina difformis 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.4 0.0 bolivina pseudoplicata 0.0 0.0 0.0 0.7 0.0 0.0 5.4 0.3 0.0 0.6 0.0 0.0 bolivina spathulata 0.0 0.0 0.0 0.0 0.0 0.0 1.4 0.0 0.0 0.0 0.0 0.0 bolivina striatula 0.0 0.0 0.0 4.0 3.3 0.0 0.7 0.0 0.0 0.0 0.0 0.0 bolivina variabilis 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 1.4 0.0 0.0 0.0 buccella sp.2 0.0 0.0 0.0 1.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 cibicides advenum 0.0 0.0 0.0 1.5 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 cibicides refulgens 0.0 0.0 0.0 0.4 0.0 0.0 1.1 0.0 0.4 0.0 0.9 0.0 cibicidoides variabilis 0.0 0.0 0.0 0.4 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 cornuspira involvens 0.0 0.0 0.0 0.0 0.0 0.0 2.5 0.0 0.0 0.0 0.0 0.0 cribroelphidium excavatum 0.0 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 cribroelphidium gerthi 0.0 0.0 0.0 1.8 0.3 0.0 1.8 21.3 8.1 7.6 21.0 6.3 g eo lo gi a c ro at ic a geologia croatica 72/128 foraminifera (species) lk-5 lk-6 lk-7 lk-2 lk-3 0–1 0–1 0–1 0–1 58–59 62–63 0–1 230–232 243–245 275–277 340–342 349–350 cribromiliolinella sp.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.4 0.0 0.0 0.0 cribrostomoides subglobosus 0.0 0.0 0.0 0.4 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 cycloforina sp. 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.4 0.0 0.0 0.0 cycloforina contorta 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.6 0.0 0.0 0.0 0.0 discorbinella sp. 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.0 0.0 elphidium sp. 0.0 0.0 0.0 0.0 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 elphidium sp.1 0.0 0.0 0.0 0.0 0.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 elphidium sp.2 0.0 0.0 0.0 0.0 0.3 0.0 0.0 0.0 0.0 0.3 0.0 0.0 elphidium sp.6 0.0 0.0 0.0 0.0 0.0 0.0 0.4 0.0 0.0 0.3 0.4 0.0 elphidium sp.7 0.0 0.0 0.0 0.0 1.3 4.0 0.0 0.0 0.0 0.0 0.0 0.0 elphidium aculeatum 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.8 0.0 0.4 0.0 elphidium advenum subsp. limbatum 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.4 0.0 elphidium cf. advenum 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.4 0.9 0.4 0.0 elphidium crispum 0.0 0.0 0.0 0.4 0.0 0.0 0.0 0.0 0.7 0.9 0.0 0.0 elphidium fichtelianum 0.0 0.0 0.0 0.0 1.0 0.0 0.4 6.9 1.1 7.0 5.7 0.0 elphidium macellum 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.3 0.0 elphidium maioricensis 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.4 0.0 0.0 0.0 elphidium margaritaceum 0.0 0.0 0.0 9.5 0.3 8.0 0.7 0.0 0.4 0.3 0.0 0.0 elphidium translucens 0.0 0.0 0.0 6.6 1.6 4.0 2.5 2.4 11.6 5.5 3.5 0.0 entzia macrescens 2.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 fissurina lucida 0.0 0.0 0.0 1.1 0.0 0.0 2.2 0.0 0.0 0.0 0.0 0.0 fursenkoina subacuta 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.0 0.0 0.0 0.0 gavelinopsis praegeri 0.0 0.0 0.0 0.7 0.0 0.0 10.5 0.0 0.0 0.0 0.0 0.0 haplophragmoides sp. 1 6.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 haplophragmoides sp. 2 1.2 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 haplophragmoides canariensis 48.8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 haynesina sp.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.7 0.0 haynesina depressula 0.0 0.0 0.0 8.4 5.9 0.0 11.9 2.4 0.7 2.4 19.7 18.8 haynesina germanica 0.0 0.0 0.0 3.6 0.0 0.0 23.1 0.6 0.7 3.3 0.0 0.0 miliammina fusca 0.3 0.0 0.0 0.4 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 miliolinella sp. 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.7 0.0 0.0 0.0 miliolinella elongata 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.8 0.3 0.0 0.0 miliolinella subrotunda 0.0 0.0 0.0 0.0 0.0 0.0 1.8 2.1 1.1 0.0 0.0 0.0 neoconorbina terquemi 0.0 0.0 0.0 0.4 0.0 0.0 0.4 0.0 0.0 0.0 0.0 0.0 peneroplis pertusus 0.0 0.0 0.0 0.0 0.0 0.0 0.7 0.3 0.0 0.3 0.0 0.0 peneroplis planatus 0.0 0.0 0.0 0.0 0.0 0.0 0.4 0.3 0.0 0.0 0.0 0.0 porosononion sp.1 0.0 0.0 0.0 0.7 0.0 0.0 0.0 5.1 0.0 2.1 0.0 0.0 porosononion sp.2 0.0 0.0 0.0 0.0 0.0 0.0 0.7 3.0 0.0 0.3 7.0 0.0 pseudotriloculina lecalvezae 0.0 0.0 0.0 0.4 0.0 0.0 0.0 0.0 0.4 0.0 0.0 0.0 quinqueloculina bosciana 0.0 0.0 0.0 0.4 0.3 0.0 0.7 0.9 0.0 0.3 0.0 0.0 quinqueloculina irregularis 0.0 0.0 0.0 0.0 0.0 0.0 0.4 0.0 0.0 0.0 0.0 0.0 quinqueloculina jugosa 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.5 1.1 0.0 0.0 0.0 quinqueloculina laevigata 0.0 0.0 0.0 0.0 0.0 0.0 0.7 3.0 1.1 0.0 0.0 0.0 quinqueloculina parvula 0.0 0.0 0.0 0.0 0.0 4.0 0.0 0.3 7.4 0.0 0.0 0.0 quinqueloculina schlumbergeri 0.0 0.0 0.0 0.0 0.0 0.0 1.4 0.0 0.7 0.0 0.0 0.0 quinqueloculina seminula 0.0 0.3 0.0 0.0 2.3 4.0 3.6 0.3 6.0 0.9 0.0 0.0 reussella spinulosa 0.0 0.0 0.0 0.0 0.0 0.0 0.4 0.0 0.0 0.0 0.0 0.0 rosalina bradyi 0.0 0.0 0.0 0.7 0.7 0.0 0.0 2.4 1.1 1.8 1.7 0.0 rosalina floridensis 0.0 0.9 14.3 0.7 0.0 0.0 1.8 1.2 0.0 0.0 0.0 0.0 rosalina macropora 0.0 0.0 0.0 0.4 0.3 0.0 1.1 1.2 0.0 0.0 0.0 0.0 sejunctella sp. 0.0 0.0 0.0 0.4 0.0 0.0 0.0 0.3 0.4 0.0 0.0 0.0 sigmavirgulina sp.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.0 0.0 sigmoilina costata 0.0 0.0 0.0 1.1 0.0 0.0 1.1 0.3 1.8 1.2 0.0 0.0 siphonoaperta sp. 0.0 0.0 0.0 0.0 0.0 0.0 0.4 0.0 0.0 0.0 0.0 0.0 siphonaperta aspera 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.4 0.3 0.0 0.0 spiroloculina sp. 0.0 0.0 0.0 0.0 0.0 0.0 0.4 1.2 0.0 0.0 0.0 0.0 spiroloculina cymbium 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.0 0.0 triloculina adriatica 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.2 0.0 0.6 0.0 0.0 table 5. continued. g eologia c roatica brunović et al.: holocene foraminiferal and geochemical records in the coastal karst dolines of cres island, croatia 29 quinqueloculina seminula) become especially abundant at core depths of 243–245 cm (unit lk-3-3). the sample from the first cm of the core is characterized by the highest abundance of haynesina germanica (23%), h. depressula (12%) and gavelinopsis praegeri (10%) (unit lk-3-4) (tab. 5, plate 2). calculation of the relative species abundances (tab. 5) revealed that 49 species were abundant at more than 1% in at least one analysed sample, with only 9 species abundant >1% in the lk-5, lk-6 and lk-7 core top samples. different locations and core depths yielded variablity in the number of species in the samples, from 7 (lk-6 core top) to 41 (lk-3 core top). samples from cores lk-5, lk-6 and lk-7 were generally less diverse in comparison to samples from cores lk-2 and lk-3. species richness decreased downcore in the sediment cores lk-2 and lk-3. the same trend was observed in the fisher α index and shannon-wiener index, while dominance shows the opposite trend. all calculated diversity indices and their variability is shown in table 5. cluster analysis indicated the existence of two clusters (fig. 7). cluster 1 encompasses two subclusters (1.1 and 1.2). subcluster 1.1 includes lk-2 and lk-3 core top samples, and several samples from the middle part of lk-3 core (230–232 cm, 243–245 cm and 340–342 cm). samples from cores lk-5 and lk-7 were grouped together in subcluster 1.2. cluster 2 consists of samples from lk-2 core (62–63 cm and 58–59 cm), basal part of lk-3 core (349–350 cm and 275–277 cm) and lk-6 core top sample. altogether, 52 sem-eds analysis were conducted on selected grains of agglutinated taxa from the lk-5 core, while several analysis were performed on calcareous taxa from the first cm of lk-5 and lk-6 sediment cores. the mineralogical composition of agglutinated taxa is variable. quartz, amphibole, mica (biotite and muscovite) and feldspars (plagioclase and potassium feldspars) are common mineral phases found in agglutinated foraminiferal tests (fig. 8). 4.2.5. geochemical analysis the result of the geochemical analyses is summarized in table 4. and figures 2 to 6. the highest toc content has been measured in the cores lk-5 (22.38%), lk-6 (17.72%) and lk-7 (15.42%) and samples from the basal part of the sediment core lk-3 (units lk-3-2 and lk-3-1; 21.42% and 11.35%, respectively) (fig. 9i). the highest tic content has been determined in cores lk-5 (10.34%) and lk-6 (11.8%) and in the samples from the topmost part of the core lk-3 (unit lk-3-4; 8.57%) (fig. 9h). the n was most abundant in the cores lk-5 (2.57%), lk-6 (2.13%) and lk-7 (2.6%), with somewhat lower abundances in the basal part of the lk-3 core (units lk-3-2 and lk-3-1; 0.92% and 0.61%, respectively) (fig.9g). most of the samples from cores lk-5, lk-6 and lk-7 were characterized by very low c/n ratios (<<12), while the highest values of c/n ratio (>12) were observed in the samples from the basal part of lk-3 (units lk-3-2 and lk-3-1) (tab. 4). the highest calcium (ca) concentrations were measured in lk-5 core (29.77%), while the lowest concentrations were observed in lk-2 core (unit lk-2-1; 7.88%). magnesium (mg) has the highest concentrations in core lk-6 (1.68%), while terrigenous elements (fe, k, al) are the most abundant in the topmost part of the lk-2 core (unit lk-2-1; e.g., fe up to 5.22%) (fig. 9b). samples from the lk-5 core have the highest p concentrations (0.11%). furthermore, the highest pb concentrations were measured in core lk-7 from podbrajde pond (86.8 mg/kg). molybdenum (mo) proved to be abundant in most cores (0.1–45.2 mg/kg), with the highest concentrations measured in the lk-3 core (unit lk-3-2) (fig. 9d). sulfur (s) concentrations vary between 0.1% and 4.3%. the highest s concentrations were found in core lk-6 (4.3%) (tab. 4; fig. 9e). 4.2.6. discriminant function analysis (dfa) of the geochemical data discriminant function analysis (dfa) of geochemical data is summarized in the composite table 6., describing the geochemical exploratory model for the sediment cores. the table comprises both the multivariate test for the overall significance of discrimination and the test of residual roots (discriminant functions). the wilks’ k statistical test is commonly used with the purpose of validating the probability level (p < 0.05) required to proceed safely with computing discriminant functions (dfs). it is used to select both the statistically significant functions as well as explaining the maximum of the within-group variation. the scatterplots of variable loadings and group centroids are constructed for the first three dfs that explain the greatest proportion of the between-group variance, almost 92% (fig. 10). in the computed model the first discriminant function df1 plays by far the greatest role in discrimination between the groups, accounting for more than 60% of the total variance (tab. 6). in the context of the environmental conditions studied, this multivariate method is particularly helpful in chasing the major sources of between-group differences originating from dissemination of the chemical elements in the sediment cores. in combining the cores from marine ponds (lk-5, lk-6 and lk-7) and foraminifera (species) lk-5 lk-6 lk-7 lk-2 lk-3 0–1 0–1 0–1 0–1 58–59 62–63 0–1 230–232 243–245 275–277 340–342 349–350 triloculina marioni 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.4 0.0 0.0 0.0 triloculina oblonga 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 2.8 0.3 0.0 0.0 trochammina inflata 41.3 0.0 42.9 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 unidentified 0.3 0.0 14.3 0.4 8.2 0.0 2.5 0.3 1.8 0.6 0.9 0.0 number of specimens (n) 334 352 7 274 305 25 277 334 285 330 229 16 number of live specimens (nl) 37 number of species (s) 7 6 32 21 39 38 38 35 20 dominance (d) 0.413 0.933 0.116 0.400 0.098 0.141 0.116 0.238 0.152 simpson (1-d) 0.587 0.067 0.884 0.601 0.902 0.859 0.884 0.762 0.848 shannon-wiener (h) 1.053 0.194 2.559 1.573 2.849 2.609 2.734 2.235 2.207 evenness (e^h/s) 0.409 0.202 0.404 0.230 0.443 0.358 0.405 0.267 0.454 equitability (j) 0.541 0.108 0.738 0.517 0.778 0.717 0.752 0.629 0.737 fisher α 1.252 1.027 9.393 5.116 12.4 11.04 11.78 9.90 5.27 table 5. continued. g eo lo gi a c ro at ic a geologia croatica 72/130 table 6. multivariate test for the overall significance of discrimination and tests of residual roots. no. of variables 14 wilks’ lambda 0.00001 approximate f ratio 24,968 degrees of freedom [112; 642] p-level <0.0000 df eigen eigen (%) canon. wilks’ chi2 df pvalue r l level 1 42,984 60.43 0.989 0.000 1170.3 112 0.000 2 17,966 25.26 0.973 0.000 793.8 91 0.000 3 4,388 6.17 0.902 0.007 501.0 72 0.000 4 2,359 3.32 0.838 0.035 333.4 55 0.000 5 1,988 2.80 0.816 0.118 212.9 40 0.000 6 1,131 1.59 0.729 0.352 103.9 27 0.000 7 0.211 0.30 0.418 0.750 28.7 16 0.026 8 0.101 0.14 0.303 0.908 9.6 7 0.214 figure 8. 1-3 potassium feldspar mineral grain recognized in haplophragmoides canariensis specimen using the sem-eds method; 4-6 plagioclase mineral grain recognized in trochammina inflata specimen using the sem-eds method. g eologia c roatica brunović et al.: holocene foraminiferal and geochemical records in the coastal karst dolines of cres island, croatia 31 distinguished sediment core units from lk-2 and lk-3 cores, nine groups of cored sediments were created to provide the most effective rapport between their geochemical signature and immediate sedimentary environment. as seen from the scatterplot of variable loadings (fig. 10), df1 is highly bipolar separating principally the lk-5 and lk-7 groups from most of the lk-3 sediment core groups (lk-3-2, lk3-3 and lk-3-4) while other groups remain to a great extent poorly differentiated sticking closer to the point of the axis intersection. the rationale for this separation is founded primarily in the negative association between p and mo. geochemically it can be understood as the lk-5 and lk-7 cores are relatively enriched in p and depleted in mo in comparison to the upper three lk-3 units. the groups positioned in the middle reflect the average composition of all the investigated core units – a “mixed” geochemical signature. df2, comprising over 25% of the total variance of geochemical data is also bipolar and can be interpreted as reflecting a negative correlation between the element suite including cu, pb, k, al, fe against another set of elements led by tic, ca, n. this pattern is a geochemical signature dividing the lk-2-1 from lk-6 groups on the basis of the clay/carbonate (inorganic carbon) background. despite making only a minor contribution to the overall model significance (6%), df3 as a monopolar function clearly highlights the lk-3-1 and lk-3-2 groups based on their affinity with c/n with a slight toc association (fig. 10). 5. discussion 5.1. foraminiferal assemblages and geochemical characterization of the surface sediments from the marine ponds on cres island studies of the foraminiferal assemblages or sediment geochemistry in the marginal marine environments along the eastern adriatic coast have been relatively scarce (mihelčić et al., 1996; vaniček et al., 2000; cuculić et al., 2009; mlakar et al., 2015; felja et al., 2015; shaw et al., 2016; sondi et al., 2017). the focus of many studies worldwide, including the western coast of the adriatic sea, has been determination of the foraminiferal fauna inhabiting these transitional environments (e.g., serandrei-barbero et al., 1999; carboni et al., 2009; kemp et al., 2013; stéphan et al., 2014; milker et al., 2015). different environmental parameters and sediment geochemistry are considered to be important for foraminiferal distribution (debenay et al., 2001; debenay & guillou, 2002; frontalini et al., 2011a; frontalini et al., 2013). the main sediment and water characteristics of the marinska, arcij and podbrajde marine ponds investigated here are shown in table 7. at the sampling time, water in the marinska pond was brackish with a temperature above 28⁰c and oxygen saturation of 15.12 mg/l. sediments in this marine pond are characterized by their high n and p contents (figs. 9f and 9g). a high p concentration in the surface sediments probably occurs due to delay in mineralisation of recently settled organic material (holtan figure 9. box and whisker plots of sediment core data. the squares in the each box represent median values. the 25th and 75th percentile are the bottom and the top of the each box, respectively. whisker ends are the non-outlier minimum and maximum values. g eo lo gi a c ro at ic a geologia croatica 72/132 et al., 1988). a source of these elements could also be input of bird faeces (guano) into the ponds (batanero et al., 2017), considering that the investigated areas are habitats for migratory marsh birds (most commonly mallardanas platyrhynchos), as well as woodcock (scolopax rusticiola) and seagulls (kralj, pers.comm.). the mallard and woodcock are also frequently hunted in the area. high nutrient concentrations enabled the development of environmental conditions that facilitated accumulation of organic matter in the sediments (figs. 9f and 9g). a low c/n ratio implies an algal origin of the preserved organic matter (meyers, 1994; meyers, 2003; lamb et al., 2006). the tic also proved to be an important sediment component (tab. 5, fig. 9h). the mo and s concentrations in the marinska pond sediments are low (figs. 9d and 10e; fig. 11a). preserved mo is not an indicator of anoxic environmental conditions and can be linked to the input of terrestrial soil material based on the high correlation of mo with al (fig. 11c) (goldberg et al., 1996). terra rossa topsoils from sites in dalmatia have a mean concentration of 3 mg/kg mo (miko et al., 2007). only agglutinated taxa typical of intertidal environments are present in the marinska marine pond. the species h. canariensis and t. inflata predominate, while e. macrescens and m. fusca are significantly less abundant. different species of the genus haplophragmoides have already been recognized in the adriatic sea (cimerman & langer, 1991; serandrei barbero et al., 2004; shaw et al., 2016), while t. inflata appears to be frequent in the marginal marine environments along the croatian coast of the adriatic sea (felja et al., 2015; shaw et al., 2016). generally, this species has been reported from many restricted, brackish water environments in the mediterranean region (serandrei barbero et al., 1999; serandrei barbero et al., 2004; debenay & guillou, 2002; frontalini et table 7. the main sediment and water characteristics of the marinska, arcij and podbrajde marine ponds. marine pond water water column depth nutrients amount organic matter mo main foraminiferal assemblages marinska marine deeper (no drying out) high high terrestrial ammonia tepida arcij brackish very shallow high high redox conditions haplophragmoides canariensis podbrajde marine shallow (drying out phases possible only at the margins of the pond) high high terrestrial scarce but present figure 10. comparison between variables and groups in the clr-transformed data discriminant function model (dfm): the scatterplots of variable loadings and discriminant scores (samples) in the reduced discriminant space of the first three discriminant functions (df1–df2 and df1–df3). g eologia c roatica brunović et al.: holocene foraminiferal and geochemical records in the coastal karst dolines of cres island, croatia 33 al., 2011a) and elsewhere (lidz & rose, 1989; sen gupta et al., 2009). recognized agglutinated foraminiferal fauna typically occur in the zone between mean sea level and mean high water level in salt-marsh areas of the adriatic sea (serandrei barbero et al., 1999; shaw et al., 2016), indicating that in the investigated environment tidal influence is important. the marinska marine pond is located 50 m from the sea and the possible tidal influence could be through karst features. although foraminiferal species richness in the marinska pond is low, recognized species seem to be well adapted to the restricted environmental conditions due to their abundance. however, a significant number of damaged tests were also observed, possibly indicating conditions unsuitable for their preservation (plate 1). debenay (2001) observed the presence of t. inflata in marshes with variable salinity and toc content, while debenay & guillou (2002) reported the preference of this species for muddy sediments in microtidal mediterranean environments. however, our results proved that although toc content was high, this species occurred in the brackish water environment with high percentages of sand (up to 75%). grain-size distribution, as well as the mineralogical composition of the sediment, has important implications for agglutinated taxa (allen et al., 1999; armynot du châtelet et al., 2008; armynot du châtelet et al., 2013). sem-eds analysis showed that identified agglutinated foraminifera from the marinska pond used variable mineral grains for building their tests (quartz, amphibole, mica and feldspars) (fig. 8). some mineral grains were not recognized in the bulk mineralogical composition of the sediment, probably due to their low abundances. this indicates the preference of agglutinated taxa for specific mineral grains. allen et al. (1999), armynot du châtelet et al. (2008), makled & langer (2010) and armynot du châtelet et al. (2013) in their studies have determined that some species preferentially select certain mineral grains from their surroundings, while significant differences among species also exist. mineral analysis also revealed the presence of the clay mineral sepiolite, usually found in restricted environments, ponds or shallow brackish lakes with high evaporation rates (ordóñez et al., 1991; velde, 1995; meunier, 2003; bustillo & alonso-zarza, 2007). direct precipitation of sepiolite occurs from solutions with abundant mg and si (mayayo et al., 1998) in the high ph environments (starkey & blackmon, 1984). bustillo & alonso-zarza (2007) indicate that sepiolite can be formed by the transformation of illites or smectites in a vadose alkaline environment with mg rich groundwater originating from dolomitic aquifers. the presence of sepiolite implies the significant impact of climate conditions (precipitation, evaporation) on the water level in the marinska pond that has been developed in a generally dolomitic lithological setting. seasonal climatic variability with periods of high evaporation from the marine pond, could have enabled the development of environmental conditions that favoured the precipitation of sepiolite in the marinska pond. conductivity (ec) and o2 measurements in the water in the arcij marine pond indicate the existence of an oxygenated enfigure 11. scatterplots of a) mo (mg/kg) against s (%) b) n (%) against p (%), c) mo (mg/kg) against al (%), d) toc (%) against c/n. g eo lo gi a c ro at ic a geologia croatica 72/134 closed marine environment. regardless of the larger distance of this marine pond from the sea (92 m), a stronger seepage of sea water probably occurs due to the well-developed karstification and fissures system of the ridge separating the pond from the sea. a silty surface sediment is enriched with toc (7.58%) and tic (8.29%), while the organic matter is predominantly of algal origin (c/n<12; meyers, 1994; meyers, 2003; lamb et al., 2006). similarly to the marinska marine pond, the primary productivity indicators (n and p) are abundant. the mo and s concentrations in the sediment are higher in comparison to the other marine ponds, causing reducing sediment conditions and thus further facilitating the preservation of organic matter. in the arcij pond, the source of mo could be different to that of the marinska pond (fig. 11c). in many papers (pedersen, 1989; crusius et al., 1996; calvert & pedersen, 1993; algeo & lyons, 2006; scholz et al., 2017) the application of mo as an indicator of redox conditions was emphasized. it is considered that mo precipitation often occurs in anoxic and organic matterrich silled basins (algeo & lyons, 2006). we suggest enrichment with mo in the arcij pond is a consequence of stagnant bottom water and reducing conditions. the s concentrations are also high (fig. 9e). the presence of hydrogen sulfide (h2s) seems to be important for the uptake of mo, especially in shallow water environments and non-silled basins (pedersen, 1989; algeo & lyons, 2006; scholz et al., 2017). this can be applicable to the arcij pond (fig. 11a), where pyrite is formed. established environmental conditions do not seem to be a limiting factor for the presence of foraminifera. the most common species occurring in the arcij pond is a. tepida, with a relative abundance of almost 97% (tab. 5). this species has been identified in numerous shallow water marine environments, restricted marginal marine environments (lagoons, estuaries, salt-marshes) and inland saline pools due to its tolerance to normal, brackish and hypersaline water conditions (jorissen, 1988; debenay, 1990; almogi-labin et al., 1992; debenay et al., 2001; debenay & guillou, 2002; debenay & guiral, 2006; murray, 2006; vidović, 2010; frontalini et al., 2011a). in previously conducted research, the ability of a. tepida to tolerate environmental stress has been emphasized (almogi-labin et al., 1992; debenay et al., 2001; debenay & guillou, 2002). abundance of this species in the organic matter-rich arcij marine pond further supports this. a significant number of living specimens was observed, implying their adaptation to the environmental conditions in the investigated marine pond. ammonia specimens with abnormal test morphology have also been recognized, further indicating the existence of environmental stress or possibly genetic or mechanical influences (almogi-labin et al., 1992). a relatively small number of living deformed specimens (6 specimens; tab. 4) was observed in the analysed sample, which does not facilitate explanation of the dominant factor causing the stress in the arcij pond. oxygen deficiency and nutrient abundance in the sediment could be possible factors. in the podbrajde marine pond, located 136 m from the sea, only 7 foraminifera specimens have been found in the analysed core top (tab. 5). this general absence of abundant foraminiferal assemblages, in comparison to the other marine ponds, could be explained by the greater distance of this environment from the sea and a more prominent disconnection from a direct marine influence. however, measured ec values indicate the existence of normal marine conditions which makes it difficult to explain the lack of rich foraminiferal assemblages. geochemical sediment analysis revealed similar conditions to those in the previously described marine ponds, especially the marinska pond, with nutrient enrichment and an algal source of organic matter (meyers, 1994; meyers, 2003; lamb et al., 2006) (tab. 4). the mo in the podbrajde marine pond also seems to be of terrestrial origin (fig. 11c) (goldberg et al., 1996). the only notable difference in the geochemical record, in comparison to the previously described ponds, is the high pb concentration (fig. 9c). generally, it is considered that elevated concentrations of cd, pb, cu and zn are a consequence of anthropogenic activities (clark, 2001). sediment enrichment with pb could also occur due to the spent shot during hunting (mateo, 2009; migani et al., 2015). the results from romano et al. (2016) imply that metallic pb from spent shot during hunting is oxidized and dissolved in wetlands leading to its mobilization and redistribution in wetland sediments. migani et al. (2015) came to similar conclusions for lagoons on the northern adriatic coast. suokhrie et al. (2017) provided an overview of studies related to foraminifera exposed to different pollutants including heavy metals. most studies indicate that high pb concentrations in marine sediments result in low diversity of fauna and the predominance of opportunistic species, as well as an increase in the abnormalities of foraminiferal tests. frontalini et al. (2015) exposed ammonia parkinsoniana specimens, cultured in mesocosms, to various concentrations of pb in sediments. specimens showed cytological modifications that might be related to pollutant-induced stress. the elevated concentrations of pb could possibly inhibit the development of abundant foraminiferal assemblages within the studied coastal marine pond. if the concentrations of pb in the studied marine pond have a major influence on the lack of an abundant foraminiferal fauna, then correlation of modern environments with those of the past (pre-flooding) could be somewhat limited. the presence of foraminifera in environments isolated from a direct marine influence has been attributed to transport by birds (debenay, 1990; almogi-labin et al., 1992). the same transport mechanism can explain the foraminiferal presence in the investigated marine ponds. however, seepage through the karstified underground is probably the dominant factor contributing to the foraminiferal dispersal. sirocco and bora winds, that are common along the eastern adriatic coast (pandžić & likso, 2005; signell et al., 2010), could also introduce marine fauna into the ponds. 5.2. palaeo-marine ponds and the palaeoenvironmental evolution of the jaz and sonte embayments differentiated units from sediment cores collected in the submerged dolines in the jaz and sonte embayments, correspond to different holocene palaeoenvironments. foraminiferal analysis was conducted only in intervals were the existence of a transitional terrestrial to marine environment was assumed. furthermore, recognized foraminiferal fauna and geochemical data were compared to the data from the marinska, podbrajde and arcij marine ponds in order to possibly detect holocene analogs of the marginal marine environments that nowadays exist in the coastal zone of cres island. foraminiferal assemblages from the core tops collected in the embayments were also investigated in order to compare typical shallow marine assemblages in the area with the taxa present downcore and in the marine ponds. a similar type of research has already been conducted in the adriatic sea in the venice lagoon (serandrei barbero et al., 2004). two distinct intervals were recognized in the sediment core lk-2 collected in the jaz embayment. the first interval (unit g eologia c roatica brunović et al.: holocene foraminiferal and geochemical records in the coastal karst dolines of cres island, croatia 35 lk-2-1), comprising the basal part of the core, implies soil accumulation with high metal concentrations (al, fe, k, cu, pb) (fig. 10) in the karst depression. the geochemical and mineralogical signature is typical for terra rossa soils developed in carbonate terrains (durn et al., 1999; miko et al., 2001). foraminiferal absence is a prominent characteristic of this environment, which further supports the palaeoenvironmental interpretation (figs. 12a and 12b). the abrupt change in the core data (unit lk-2-2) (fig. 5) was observed at approximately 711 cal bp evidencing an important environmental transition. a significant rise in the mo and s concentrations (fig. 5) probably indicates establishment of an oxygen depleted restricted water body (pedersen, 1989; crusius et al., 1996; calvert & pedersen, 1993; algeo & lyons, 2006; scholz et al., 2017). the high toc content supports this, while also implying increased primary productivity (fig. 5). however, it seems that this environment was not as productive as the present-day marine ponds on cres island or these differences could be a consequence of diagenesis (figs. 9f figure 12. schematic drawing of the palaeoenvironmental development of the marinska, arcij and podbrajde marine ponds and the jaz and sonte embayments at a) approximately 7000 cal bp, b) approximately 6610 cal bp, c) approximately 711 cal bp, d) present. g eo lo gi a c ro at ic a geologia croatica 72/136 and 9g; fig. 11b). the c/n ratio is indicative of a mixed terrestrial and algal organic matter provenance, which also differs in comparison to the present-day marine ponds (fig. 11d) (meyers, 1994; meyers, 2003; lamb et al., 2006). at this transition in core lk-2, a more detailed analysis of foraminiferal assemblages was conducted (fig. 3). the presence of foraminifera proved that the marine influence in the jaz embayment begun at approximately 711 cal bp. a poorly diversified assemblage was determined, predominantly composed of numerous specimens of foraminifera typical of the brackish or shallow marine conditions usually established in the marginal marine environments (a. tepida, a. parkinsoniana and h. depressula) (murray, 2006; vaniček et al., 2000). differentiated species seem to be well adapted to the reduced oxygen availability in the sediment. the susceptibility of a. tepida and the genus haynesina to environmental stress has been previously determined (almogi-labin et al., 1992; debenay et al., 2000; debenay et al., 2001; debenay & guillou, 2002; vidović et al., 2009). however, a. parkinsoniana is not considered to be a stress-tolerant species (vidović et al., 2014). cluster analysis enabled the identification of different core intervals characterized by similar assemblages (fig. 7). we consider the similarity of samples from the transitional zone of the jaz core and samples from the arcij marine pond as evidence of the establishment of similar environments. therefore, a palaeo-marine pond with a strong marine influence, analogous to the present-day arcij marine pond, developed at approximately 711 cal bp when the sea-water level approached the depth of the sill at –0.5 m (fig. 12c). however, statistical analysis of geochemical data does not fully support this interpretation (fig. 10), possibly due to differences in the geological setting of the arcij marine pond and the jaz embayment where siliciclastic input is more prominent (fig. 10). it is probable that this environment existed for a very short time before it was flooded with sea-water and the jaz embayment was formed. the lk-2 core top analysis implies the existence of an oxygen depleted sedimentary environment in the present-day jaz embayment (fig. 12d). geochemical analysis of the surface sediment revealed high mo concentrations (8.2 mg/kg) and lower toc and tic contents in comparison to the investigated inland marine ponds. a significant difference is in the nutrient availability and source of organic matter, with a high c/n ratio indicating mixed algal and terrestrial organic matter origin (meyers, 1994; meyers, 2003; lamb et al., 2006). the core top sample proved to contain a highly diversified foraminiferal assemblage in comparison to present-day marine ponds, with 32 recognized species. the most common species a. tepida, a. parkinsoniana, ammonia sp., b. striatula, e. margaritaceum, e. translucens and h. depressula are typical for organic matter enriched marine environments along the eastern adriatic coast (vidović, 2010). palaeoenvironmental development of the sonte embayment encompasses a longer time span (figs. 12a and 12d). the present-day sonte embayment has a maximum depth of 5 m, while the sill depth is 3 m. accumulation of the sediment sequence was possible due to the morphology of this depression. analysed samples from the lowermost part of the core exhibit similarity in geochemical and mineralogical composition to the basal part of the lk-2 core (fig. 10) and indicate terrestrial soil (durn et al., 1999; miko et al., 2001). within this interval (unit lk-3-1) poorly preserved specimens of foraminifera occur in low numbers, making it difficult to interpret an established environment. the rare specimens were probably deposited due to transport by waves and/or winds as a consequence of the gradual mid-holocene sea level rise on the seaward side of the karstified sill/barrier. further up-core (unit lk-3-2), a significant rise in the toc content was observed (fig. 9i). we suggest development of a stagnant water body at approximately 8000 cal bp (according to the age-depth model) on previously formed soil. increased nutrient availability could facilitate organic matter production, similar to the marinska, podbrajde and arcij marine ponds (fig. 11b). however, most of the organic matter has a terrestrial source possibly indicating input from the land under a different climatic setting or the enhanced growth of terrestrial plants (fig. 11d). this interval could be correlated with the holocene pluvial period recognized in the adriatic sea (wunsam et al., 1999; schmidt et al., 2001) and in the lacustrine sediments from karst poljes and lakes located along the eastern adriatic coast (schmidt et al., 2000; balbo et al., 2006; ilijanić et al., 2018). the established environment was probably poorly oxygenated, which enabled the preservation of organic matter. relatively high values and covariation of mo and toc corroborates this conclusion (crusius et al., 1996; calvert & pedersen, 1993; algeo & lyons, 2006; scholz et al., 2017). the mo concentrations are significantly higher in comparison to the present-day concentrations in the marine ponds (fig. 9d), indicating low oxygen abundance due to the development of a restricted environment with water stratification. the s concentrations are high and similar to those in the marinska, arcij and podbrajde marine ponds on cres island, further supporting the development of a restricted and oxygen poor water body (fig. 9e, fig. 11a). dominant taxa, a. tepida, ammonia beccarii, h. depressula, asterigerinata mamilla, porosononion sp., elphidium fichtelianum and c. gerthi imply the existence of shallow marine to possibly slightly brackish water environmental conditions (murray, 2006). a. tepida and a. beccarii have been frequently observed in the sediments along the eastern coast of the adriatic sea with high p and toc content (vidović et al., 2014). the presence of the genus haynesina can also be correlated with the enrichment of toc in sediment (debenay et al., 2001; vidović et al., 2009; vidović et al., 2014). statistical analysis demonstrated the highest similarity of the foraminiferal assemblages from this unit with the present-day arcij marine pond and previously described transitional zone in the core from the jaz embayment. this suggests development of a palaeo-marine pond with normal marine water (fig. 12a). however, such similarity was not observed in the statistically analysed geochemical data, where this unit correlates well with the topmost part of the jaz embayment core therefore implying similarity of these environments (fig. 10). micropalaeontological data and geochemistry therefore suggest different palaeoenvironments, but generally provide evidence of a significant marine influence during the deposition of sediments from unit lk-3-2. at 6610 cal bp (unit lk-3-3) a decrease in toc content and mo concentrations, followed by an increase in tic indicate major environmental change in comparison to the previously described unit (fig. 6). carbonates become a more important sediment component (fig. 9h, fig. 10). surface sediments deposited along the present-day eastern adriatic coast are also enriched in carbonates (pikelj et al., 2009; pikelj, 2010). the newly formed environment was nutrient-deprived, which prevented organic matter accumulation (fig. 11b). however, preserved organic matter has mixed algal-terrestrial origin (tab. 4, fig. 6) (meyers, 1994; meyers, 2003; lamb et al., 2006). foraminiferal assemblages became highly diversified and dominated by a. tepg eologia c roatica brunović et al.: holocene foraminiferal and geochemical records in the coastal karst dolines of cres island, croatia 37 ida, e. translucens, a. beccarii, ammonia sp., c. gerthi, e. fichtelianum, porosononion sp.1, q. parvula and q. seminula specimens. dominant species are similar to the previously described interval. however, species richness and diversity increased significantly. increases in the relative abundance of miliolids were also observed. this can suggest the existence of an enclosed environment (debenay & guillou, 2002; lidz & rose, 1989) or hypersaline lagoon (debenay et al., 2001). genus quinqueloculina is abundant in the mljet lakes (ćoso-vić et al., 2016), while debenay & guillou (2002) reported the association of a. tepida and q. seminula in the subtidal areas, marshes and mudflats with developed seaweeds. according to vidović (2010) miliolids are common in marine environments along the croatian coast of the adriatic sea. the determined assemblage, predominantly comprising the genera ammonia, elphidium, haynesina and quinqeloculina, can be compared to the previously recognized haynesina-ammonia assemblage from the shallow marine environments in the soline embayment and nin bay (vidović, 2010). cluster analysis grouped samples from this unit into the same subcluster as the surface sample from the jaz embayment where shallow marine environmental conditions prevail today. statistical analysis of the geochemical data also indicated this similarity. it is our interpretation that at 6610 cal bp a marine influence became more prominent in the sonte embayment, possibly with the sea water spilling over the sill (fig. 12b). this is in general agreement with the published global and regional sea level curves (correggiari et al., 1996; waelbroek et al., 2002; lambeck et al., 2014; vacchi et al., 2016). the topmost part of the core (unit lk-3-4) can be geochemically distinguished from the previously described core intervals (fig. 6). this is probably indicative of the establishment of a more permanent, fully marine environment (fig. 12d). a highly diversified foraminiferal assemblage consisting of 41 recognized species was determined in the lk-3 core top. the dominant sonte embayment foraminiferal fauna (g. praegeri, h. depressula, h. germanica, a. tepida, a. mamilla and bolivina pseudoplicata) is typical for littoral environments in the adriatic sea (jorissen, 1988; vidović, 2010). in the investigated embayment, the determined surface assemblage is present in the sand dominated sediment, with low mo and s concentrations, low toc content and high tic values (fig. 6). however, although the sediment is oxygenated, measured oxygen concentrations in the water were the lowest among all the investigated environments (tab. 2), probably due to the greater depth of this environment. primary productivity in the sonte embayment is limited due to the nutrient deficiency (fig. 11b) and therefore organic matter content is low (fig. 9i). cluster analysis grouped foraminifera from this sample into the same subcluster as the previously described marine samples (fig. 7). statistical analysis of the geochemical data indicated a similarity to other marine units from the lk-3 and lk-2 cores (fig. 10). 6. conclusions marine ponds have been developed in the coastal karst dolines along cres island. sediments preserved in the marinska, arcij and podbrajde marine ponds revealed important micropalaeontological and geochemical data that was used to characterize these marginal marine environments. detailed analysis of sediment cores from the jaz and sonte embayments, developed in now submerged dolines, revealed the complex palaeoenvironmental evolution of the investigated area. the downcore micropalaeontological and geochemical data enabled detection of the holocene palaeo-marine ponds. we suggest the development of a palaeo-marine pond, similar to the present-day arcij pond, at approximately 711 cal bp in the jaz embayment. a palaeo-marine pond in the sonte embayment existed up to 6610 cal bp. these palaeo-marine ponds were flooded during the holocene sea level rise, when the marine environment was established. therefore, recognition of different environments developed in the karst dolines, located in the coastal zone of cres island, was possible. the research of the present-day marginal marine environments along the eastern adriatic coast could prove to be valuable for palaeoenvironmental studies and especially holocene sea level change research. acknowledgement this research was funded by the croatian science foundation (hrzz) through the interdisciplinary project „lost lake landscapes of the eastern adriatic shelf“ (loladria; project no. 9419). the authors would like to thank hrvoje burić and edin badnjević for their help during the fieldwork campaign and ana-maria heski and helena ćućuzović for performing grain-size analysis. we would also like to thank editor mladen juračić and two anonymous reviewers whose comments significantly improved the manuscript. furthermore, we thank the „mopp-medflood“ community and inqua for financing attendances on their workshops and field excursions where some results of this study were presented and discussed. references algeo, t.j. & lyons, t.w. (2006): mo-total organic carbon covariation in modern anoxic marine environments: implications for analysis of paleoredox and paleohydrographic conditions.– paleoceanography, 21/1, pa1016. doi:10.1029/ 2004pa001112 allen, k., roberts, s. & murray, j.w. (1999): marginal marine agglutinated foraminifera: affinities for mineral phases.– j. micropalaeontology, 18/2, 183–191. doi: 10.1144/jm.18.2.183 almogi-labin, a., perelis-grossovicz, l. & raab, m. (1992): living ammonia from a hypersaline inland pool, dead sea area, israel.– j. foraminifer. res., 22/3, 257–266. doi: 10.2113/gsjfr.22.3.257 alve, e. & murray, j.w. (1999): marginal marine environments of the skagerrak and kattegat: a baseline study of living (stained) benthic foraminiferal ecology.– palaeogeogr. palaeoclimatol. palaeoecol., 146, 171–193. doi: 10.1016/s0031-0182 (98)00131-x anadón, p., gliozzi, e. & mazzini, i. (2002): paleoenvironmental reconstruction of marginal marine environments from combined paleoecological and geochemical analyses on ostracods.– geophys. monogr. ser., 131, 227–247. doi: 10.1029/ 131gm12 armynot du châtelet, e., recourt, p. & chopin, v. (2008): mineralogy of agglutinated benthic foraminifera; implications for paleo-environmental reconstructions.– bull. la soc. geol. fr., 179/6, 583–592. doi: 10.2113/gssgfbull.179.6.583 armynot du châtelet, e., bout-roumazeilles, v., coccioni, r., frontalini, f., guillot, f., kaminski, m.a., recourt, p., riboulleau, a., trentsaux, a., tribovillard, n. & ventalon, s. (2013): environmental control on shell structure and composition of agglutinated foraminifera along a proximal-distal transect in the marmara sea.– mar. geol., 335, 114– 128. doi: 10.1016/j.margeo.2012.10.013 balbo, a.l., andrič, m., rubinić, j., moscariello, a. & miracle, p.t. (2006): palaeoenvironmental and archaeological implications of a sediment core from polje čepić, istria, croatia.– geol. croat., 59/2, 109–124. batanero, g.l., león-palmero, e., li, l., green, a.j., rendón-martos, m., suttle, c.a. & reche, i. (2017): flamingos and drought as drivers of nutrients and microbial dynamics in a saline lake.– scientific rep., 7/1, 1–13. doi: 10.1038/s41598-017-12462-9 benac, č. & durn, g. (1997): terra rossa in the kvarner area: geomorphological conditions of formation.– acta geographica croatica, 32/1, 7–19. benac, č. & juračić, m. (1998): geomorphological indicators of sea level changes during upper pleistocene (würm) and holocene in the kvarner region (ne adriatic sea).– acta geographica croatica, 33, 27–45. g eo lo gi a c ro at ic a geologia croatica 72/138 bianchi, n., fortino, s., leonzio, c. & ancora, s (2011): ecotoxicological study on lead shot from hunting in the padule di fucecchio marsh (tuscany, italy).– chem. ecol., 27, 153–166. doi: 10.1080/02757540.2011.625941 benjamin, j., rovere, a., fontana, a., furlani, s., vacchi, m., inglis, r.h., galili, e., antonioli, f., sivan, d., miko, s., mourtzas, n., felja, i., meredith-williams, m., goodman-tchernov, b., kolaiti, e., anzidei, m. & gehrels, r. (2017): late quaternary sea level changes and early human societies in the central and eastern mediterranean basin: an interdisciplinary review.– quat. int., 449, 29–57. doi: 10.1016/j.quaint.2017.06.025 blott, s.j. & pye, k. (2001): gradistat: a grain size distribution and statistics package for the analysis of unconsolidated sediments.– earth surf. process landforms, 26, 1237–1248. doi: 10.1002/esp.261 boltovskoy, e. & lena, h. (1971): the foraminifera (except family allogromiidae) which dwell in fresh water.– j. foraminifer res., 1, 71–76. doi: 10.2113/gsjfr.1.2.71 borghesi, f. (2016): environmental pollution and hunting: exposure of birds to metals in their trophic areas, and of humans to lead in game birds.– phd thesis, university of bologna, 217 p. bustillo, m.a. & alonso-zarza, a.m. (2007): overlapping of pedogenesis and meteoric diagenesis in distal alluvial and shallow lacustrine deposits in the madrid miocene basin, spain.– sedimentary geology, 198/3–4, 255–271. doi: 10.1016/j. sedgeo.2006.12.006 calvert, s.e. & pedersen, t.f. (1993): geochemistry of recent oxic and anoxic marine sediments: implications for the geological record.– mar geol., 113, 67–88. doi: 10.1016/0025-3227(93)90150-t cann, j.h. & de dekker, p. (1981): fossil quaternary and living foraminifera from athalassic (non-marine) saline lakes, southern.– journal of paleontology, 55/3, 660– 670. carboni, m.g., succi, m.c., bergamin, l., di bella, l., frezza, v. & landini, b. (2009): benthic foraminifera from two coastal lakes of southern latium (italy). preliminary evaluation of environmental quality.– mar. pollut. bull., 59, 268–280. doi: 10.1016/j.marpolbul.2009.08.010 cimerman, f. & langer, m.r. (1991): mediterranean foraminifera.– razred za naravoslovne vede, classis iv: historia naturalis, opera 30. slovenska akademija, ljubljana, str. 118 +93 pls. clark, r.b. (2001): marine pollution, 5th edition.– oxford univ. press, oxford, uk, 248 p. correggiari, a., roveri, m. & trincardi, f. (1996): late pleistocene and holocene evolution of the north adriatic sea.– ii quaternario, italian journal of quaternary sciences, 9, 697–704. crusius, j., calvert, s., pedersen, t. & sage, d. (1996): rhenium and molybdenum enrichments in sediments as indicators of oxic, suboxic and sulfidic conditions of deposition.– earth planet sci. lett., 145, 65–78. doi: 10.1016/s0012821x(96)00204-x cuculić, v., cukrov, n., kwokal, ž. & mlakar, m. (2009): natural and anthropogenic sources of hg, cd, pb, cu and zn in seawater and sediment of mljet national park, croatia. estuar.– coast. shelf sci., 81, 311–320. doi: 10.1016/j.ecss.2008.11.006 cukrov, n., frančišković-bilinski, s. & bogner, d. (2014): metal contamination recorded in the sediment of the semi-closed bakar bay (croatia).– environ. geochem. health, 36/2, 195–208. doi: 10.1007/s10653-013-9558-3 ćosović, v., zavodnik, d., borčić, a., vidović, j., deak, s. & moro, a. (2011): a checklist of foraminifera of the eastern shelf of the adriatic sea.– zootaxa, 3035, 1–56. ćosović, v., gajski, n., ptčiek, a., vidović, j., & kružić, p. (2016): the distribution of benthic foraminifera in cladocora caespitosa coral banks of the veliko jezero sediments (mljet national park, eastern adriatic sea).– neues jahrbuch für geologie und paläontologie abhandlungen, 279/3, 323–340. doi: 10.1127/ njgpa/2016/0559 davis, j.c. (1973): statistics and data analysis in geology.– john wiley & sons, new york, 550 p. davis, j.c. (1986): statistics and data analysis in geology.– john wiley & sons, new york, 646 p. debenay, j.p. & guillou, j.j. (2002): ecological transitions indicated by foraminiferal assemblages in paralic environments.– estuaries, 25, 1107–1120. doi: 10.1007/ bf02692208 debenay, j.p. & guiral, d. (2006): mangrove swamp foraminifera, indicators of sea level or paleoclimate?– rev. paleobiol., 25/2, 567–574. debenay, j.p. (1990): recent foraminiferal assemblages and their distribution relative to environmental stress in the paralic environments of west africa (cape timiris to ebrie lagoon).– j. foraminifer. res., 20/3, 267–282. doi: 10.2113/gsjfr.20.3.267 debenay, j.p., gesilin, e., eichler, b.b., duleba, w., sylvestre, f. & eichler, p. (2001): foraminiferal assemblages in a hypersaline lagoon, araruama (r.j.) brazil.– j. foraminifer. res., 31/2, 133–151. doi: 10.2113/0310133 delaney, m.l. (1998): phosphorus accumulation in marine sediments and the oceanic phosphorus cycle.– global biogeochem cycles, 12/4, 563–572. doi: 10.1029/ 98gb02263 di, z., zhang, h. & shan, b. (2015): using sedimentary phosphorus/nitrogen as indicators of shallow lake eutrophication: concentrations or accumulation fluxes.– environ. earth. sci., 74/5, 3935–3944. doi: 10.1007/s12665-015-4465-9 dillon, w.r. & goldstein, m. (1984): multivariate analysis: methods and applications.– john wiley & sons, new york, 587 p. dix, g.r., patterson, r.t. & park, l.e. (1999): marine saline ponds as sedimentary archives of late holocene climate and sea level variation along a carbonate platform margin: lee stocking island, bahamas.– palaeogeogr. palaeoclimatol. palaeoecol., 150/3–4, 223–246. doi: 10.1016/s0031-0182(98)00184-9 doneus, n., doneus, m. & ettinger-starčić, z. (2017): the ancient city of osor, northern adriatic, in integrated archaeological prospection.– hortus artium mediev., 23/2, 761–775. doi: 10.1484/j.ham.5.113761 durn, g., ottner, f. & slovenec, d. (1999): mineralogical and geochemical indicators of the polygenetic nature of terra rossa in istria, croatia.– geoderma, 91/1– 2, 125–150. doi: 10.1016/s0016-7061(98)00130-x edwards, r.j., wright, a.j. & van de plassche, o. (2004): surface distributions of salt-marsh foraminifera from connecticut, usa: modern analogues for high-resolution sea level studies.– mar. micropaleontol., 51/1–2, 1–21. doi: 10. 1016/j.marmicro.2003.08.002 emmanouilidis, a., katrantsiotis, c., norström, e., risberg, j., kylander, m., sheik, t.a., iliopoulos, g. & avramidis, p. (2018): middle to late holocene palaeoenvironmental study of gialova lagoon, sw peloponnese, greece.– quat. int., 476, 46–62. doi: 10.1016/j.quaint.2018.03.005 faivre, s., bakran-petricioli, t., barešić, j. & horvatinčić, n. (2015): new data on marine radiocarbon reservoir effect in the eastern adriatic based on pre-bomb marine organisms from the intertidal zone and shallow sea.– radiocarbon, 57/4, 527–538. doi: 10.2458/azu_rc.57.18452 felja, i., fontana, a., furlani, s., bajraktarević, z., paradžik, a., topalović, e., rossato, s., ćosović, v. & juračić, m. (2015): environmental changes in the lower mirna river valley (istria, croatia) during the middle and late holocene.– geol croat., 68/3, 209–224. doi: 10.4154/gc.2015.16 folk, r.l. & ward, w.c. (1957): brazos river bar: a study in the significance of grain size parameters.– journal of sedimentary petrology, 27, 3–26. doi: 10.1306/ 74d70646-2b21-11d7-8648000102c1865d ford, d.c. & williams, p. (1989): karst geomorphology and hydrology.– chapman & hall, london, 601 p. doi: 10.1007/978-94-011-7778-8 frontalini, f., armnynot du châtelet, e., debenay, j.p., coccioni, r. & bancalà, g. (2011a): benthic foraminifera in coastal lagoons: distributional patterns and biomonitoring implications.– in: friedman, a.g. (eds.): lagoons: biology, management and environmental impact. nova science publishers, inc., 39–72. frontalini, f., semprucci, f., coccioni, r., balsamo, m., bittoni, p. & covazzi-harriague, a. (2011b): on the quantitative distribution and community structure of the meio and macrofaunal communities in the coastal area of the central adriatic sea (italy).– environ. monit. assess, 180, 325–344. doi: 10. 1007/s10661-010-1791-y frontalini, f., margaritelli, g., francescangeli, f., rettori, r., armnynot du châtelet, e., coccioni, r. (2013): benthic foraminiferal assemblages and biotopes in a coastal lake: the case study of lake varano (southern italy).– acta protozool., 52/3, 147–160. frontalini, f., curzi, d., giordano, f.m., bernhard, j.m., falcieri, e. & coccioni, r. (2015): effects of lead pollution on ammonia parkinsoniana (foraminifera): ultrastructural and microanalytical approaches.– european journal of histochemistry, 59/1, 2460. doi: 10.4081/ejh.2015.2460 fuček, l., matičec, d., vlahović, i., oštrić, n., prtoljan, b., korbar, t. & husinec, a. (2012): osnovna geološka karta republike hrvatske mjerila 1:50 000 – list cres 2 [basic geological map of republic of croatia 1:50 000, cres 2 sheet – in croatian].– hrvatski geološki institut, zagreb. fuček, l., matičec, d., vlahović, i., oštrić, n., prtoljan, b., korbar, t., husinec, a. & palenik, d. (2014): osnovna geološka karta republike hrvatske mjerila 1:50 000 – list cres 4. [basic geological map of republic of croatia 1:50 000, cres 4 sheet – in croatian].– hrvatski geološki institut, zagreb. gajić-čapka, m., cindrić, k. & mihajlović, d. (2008): oborina/precipitation.– in: zaninović, k. (eds.): klimatski atlas hrvatske / climate atlas of croatia 1961–1990., 1971–2000. državni hidrometeorološki zavod, zagreb, 34–50. galović, l. & peh, z. (2016): mineralogical discrimination of the pleistocene loess/ paleosol sections in srijem and baranja, croatia.– aeolian res., 21, 151–162. doi: 10.1016/j.aeolia.2016.04.006. gehrels, w.r. (1994): determining relative sea-level change from salt-marsh foraminifera and plant zones on the coast of maine, u.s.a.– j coast res., 10/4, 990–1009. goldberg, s., forster, h.s. & godfrey, c.l. (1996): molybdenum adsorption on oxides, clay minerals, and soils.– soil sci. soc. am. j., 60/2, 425–432. doi: 10.2136/sssaj1996.03615995006000020013x govorčin, d.p., juračić, m., horvatinčić, n. & onofri, v. (2001): holocene sedimentation in the soline channel (mljet lakes, adriatic sea).– natura croatica, 10/4, 247–258. g eologia c roatica brunović et al.: holocene foraminiferal and geochemical records in the coastal karst dolines of cres island, croatia 39 hammer, ø., harper, d.a.t. & ryan, p.d. (2001): past: paleontological statistics software package for education and data analysis.– palaeontologia electronica 4, 9. http://palaeo-electronica.org/2001_1/past/issue1_01.htm hayward, b.w., grenfell, h.r. & scott, d.b. (1999): tidal range of marsh foraminifera for determining former sea level heights in new zealand.– new zeal. j. geol. geophys., 42/3, 395–413. doi: 10.1080/00288306.1999.9514853 helali, m.a., oueslati, w., zaaboub, n., added, a. & abdeljaouad, s. (2013): geochemistry of marine sediments in the mejerda river delta, tunisia.– chem. speciat. bioavailab., 25/4, 247–257. doi: 10.3184/095422913x138400981 60825 holtan, h., kamp-nielsen, l. & stuanes, a.o. (1988): phosphorus in soil, water and sediment: an overview.– hydrobiologia, 170, 19–34. doi: 10.1007/ bf00024896 husinec, a., velić, i., fuček, l., vlahović, i., matičec, d., oštrić, n. & korbar, t. (2000): mid cretaceous orbitolinid (foraminiferida) record from the islands of cres and losinj (croatia) and its regional stratigraphic correlation.– cretac. res., 21/1, 155–171. doi: 10.1006/cres.2000.0203 ilijanić, n., miko, s., hasan, o. & bakrač, k. (2018): holocene environmental record from lake sediments in the bokanjačko blato karst polje (dalmatia, croatia).– quat int. (in press). https://doi.org/10.1016/j.quaint.2018.01.037 jayalakshmy, k.v. & rao, k.k. (2006): aspects of the biodiversity of brackish water foraminifera.– environ. forensics., 7/4, 353–367. doi: 10.1080/ 15275920600996370 jorissen, f.j. (1988): benthic foraminifera from the adriatic sea; principles of phenotypic variation.– utrecht micropaleontological bulletins, 37, 174 p. juračić, m., sondi, i., barišić, d. & pravdić, v. (1995): sedimenti i sedimentacija u mljetskim jezerima (hrvatska). prirodne značajke i društvena valorizacija otoka mljeta.– in: durbešić, p. & benović, a. (eds.): ekološke monografije 6. hrvatsko ekološko društvo, pomena, otok mljet, 107–116. juračić, m., benac, č., & crmarić, r. (1999): seabed and surface sediment map of the kvarner region, adriatic sea, croatia (lithological map, m 1:500,000).– geol. croat., 52, 131–140. kelletat, d.h. (2005): dalmatian coasts.– in: schwartz, m.l. (eds.): encyclopedia of coastal science.– encyclopedia of earth sciences series. dordrecht, the netherlands, springer, 456–462. doi: 10.1007/1-4020-3880-1_107 kemp, a.c., telford, r.j., horton, b.p., anisfeld, s.c. & sommerfield, c.k. (2013): reconstructing holocene sea level using salt-marsh foraminifera and transfer functions: lessons from new jersey, usa.– j. quat. sci., 28/6, 617–629. doi: 10.1002/jqs.2657 komar, d., dolenec, m., lambaša belak, ž., matešić, s.s., lojen, s., kniewald, g., vrhovnik, p., dolenec, t. & rogan šmuc, n. (2015): geochemical characterization and environmental status of makirina bay sediments (northern dalmatia, republic of croatia).– geol. croat., 68/1, 79–92. doi: 10.4154/ gc.2015.06 korbar, t. & husinec, a. (2003): biostratigraphy of turonian to (?) coniacian platform carbonates: a case study from the cres island (northern adriatic, croatia).– geol. croat., 56/2, 173–185. korbar, t., fuček, l., husinec, a., vlahović, i., oštrić, n., matičec, d. & jelaska, v. (2001): cenomanian carbonate facies and rudists along shallow intraplatform basin margin-the island of cres (adriatic sea, croatia).– facies, 45, 39–58. doi: 10.1007/bf02668104 lamb, a.l., wilson, g.p. & leng, m.j. (2006): a review of coastal palaeoclimate and relative sea level reconstructions using δ13c and c/n ratios in organic material.– earth-science rev., 75/1–4, 29–57. lambeck, k., rouby, h., purcell, a., sun, y. & sambridge, m. (2014): sea level and global ice volumes from the last glacial maximum to the holocene.– proc. natl. acad. sci., 111/43, 15296–15303. doi: 10.1073/pnas.1411762111 lidz, b.h. & rose, p. (1989): diagnostic foraminiferal assemblages of florida bay and adjacent shallow waters: a comparison.– bulletin of marine science, 44/1, 399–418. loeblich, jr., a.r. & tappan, h. (1987): foraminiferal genera and their classification.– van nostrand reinhold, new york, 970 p. doi: 10.1007/978-1-4899-5760-3 loring, d.h. (1978): geochemistry of zinc, copper and lead in the sediments of the estuary and gulf of st lawrence.– can. j. earth. sci., 15, 757–772. doi: 10.1139/ e78-082 lovell, d., pawlowsky-glahn, v., egozcue, j.j., marguerat, s. & bähler, j. (2015): proportionality: a valid alternative to correlation for relative data.– plos comput. biol., 11/3, 1–12. doi: 10.1371/journal.pcbi.1004075. mackenzie, f.t., vink, s., wollast, r. & chou, l. (1995): comparative geochemistry of marine saline lakes.– in: lerman, a., imboden, d.m. & gat, j.r. (eds.): physics and chemistry of lakes. springer verlag, berlin, 265–278. doi: 10.1007/978-3-642-85132-2_9 magaš, n. (1968): osnovna geološka karta sfrj, list cres, 1:100 000, l33-113 [basic geological map of sfrj: cres sheet l33-113 – in croatian].– institut za geološka istraživanja, zagreb. savezni geološki zavod, beograd. makled, w.a. & langer, m.r. (2010): preferential selection of titanium-bearing minerals in agglutinated foraminifera: ilmenite (fetio3) in textularia hauerii d’orbigny from the bazaruto archipelago, mozambique.– rev. micropaleontol., 53, 163–173. doi: 10.1016/j.revmic.2009.11.001 mamužić, p. (1968): osnovna geološka karta sfrj, list lošinj, 1:100 000, l33-125 [basic geological map of sfrj: cres sheet l33-125 – in croatian].– institut za geološka istraživanja, zagreb. savezni geološki zavod, beograd. marriner, n., morhange, c., faivre, s., flaux, c., vacchi, m., miko, s., dumas, v., boetto, g. & radic rossi, i. (2014): post-roman sea level changes on pag island (adriatic sea): dating croatia’s “enigmatic” coastal notch?– geomorphology, 221, 83–94. doi: 10.1016/j.geomorph.2014.06.002 mateo, r. (2009): lead poisoning in wild birds in europe and the regulations adopted by different countries.– in: watson, r.t., fuller, m., pokras, m. & hunt, w.g. (eds.): ingestion of lead from spent ammunition: implications for wildlife and humans. the peregrine fund, boise, idaho, usa. doi: 10.4080/ilsa.2009.0107 mayayo, m.j., torres-ruiz, j., gonzalez-lopez, j.m., lopez-galindo, a. & bauluz, b. (1998): mineralogical and chemical characterization of the sepiolite mg-smectite deposit at mara (calatayud basin, spain).– eur. j. mineral., 10/2, 367–383. doi: 10.1127/ejm/10/2/0367 meunier, a. (2003): clays.– springer verlag, berlin, heidelberg, 476 p. meyers, p.a. (1994): preservation of elemental and isotopic source identification of sediemntary organic matter.– chem. geol., 114, 289–302. meyers, p.a. (2003): application of organic geochemistry to paleolimnological reconstruction: a summary of examples from the laurention great lakes.– org. geochem., 34, 261–289. doi: 10.1016/s0146-6380(02)00168-7 migani, f., borghesi, f. & dinelli, e. (2015): geochemical characterization of surface sediments from the northern adriatic wetlands around the po river delta. part i: bulk composition and relation to local background.– journal of geochemical exploration, 156, 72–88. mihelčić, g., šurija, b., juračić, m., barišić, d. & branica, m. (1996): history of the accumulation of trace metals in sediments of the saline rogoznica lake (croatia).– sci. total environ., 182/1–3, 105–15. miko, s., halamić, j., peh, z. & galović, l. (2001): geochemical baseline mapping of soils developed on diverse bedrock from two regions in croatia.– geol. croat., 54/1, 53–118. miko, s., koch, g., mesič, s., šparica-miko, m., šparica, m., čepelak, r., bačani, a., vreča, p., dolenec, t. & bergant, s. (2008): anthropogenic influence on trace element geochemistry of healing mud (peloid) from makirina cove (croatia).– environ. geol., 55, 517–537. doi: 10.1007/s00254-0070997-y miko, s., koch, g., mesić, s., šparica-miko, m., šparica, m., vreča, p. & dolenec, t. (2007): influence of land use in small karst watersheds on the chemical status of peloid sediments on the eastern adriatic coast.– j. soils sediments, 7/5, 303–312. doi: 10.1065/jss2007.10.25 milker, y., horton, b.p., nelson, a.r., engelhart, s.e. & witter, r.c. (2015): variability of intertidal foraminiferal assemblages in a salt marsh, oregon, usa.– mar micropaleontol, 118, 1–16. doi: 10.1016/j.marmicro.2015.04.004 mlakar, m., fiket, ž., geček, s., cukrov, n. & cuculić, v. (2015): marine lake as in situ laboratory for studies of organic matter influence on speciation and distribution of trace metals.– shelf research, 103, 1–11. doi: 10.1016/j.csr.2015. 04.024 mocochain, l., audra, p., clauzon, g., bellier, o., bigot, j.y., parize, o. & monteil, p. (2009): the effect of river dynamics induced by the messinian salinity crisis on karst landscape and caves: example of the lower ardèche river (mid rhône valley).– geomorphology, 106/1–2, 46–61. doi: 10.1016/j.geomorph. 2008.09.021 moore, d.m. & reynolds, r.c. (1997): x-ray diffraction and the identification and analysis of clay minerals.– second edition. oxford univ. press, oxford, 378 p. müller-navara, k., milker, y. & schmiedl, g. (2017): applicability of transfer functions for relative sea level reconstructions in the southern north sea coastal region based on salt-marsh foraminifera.– marine micropaleontology, 135, 15– 31. doi: 10.1016/j.marmicro.2017.06.003 murray, j.w. (2006): ecology and applications of benthic foraminifera.– cambridge university press, cambridge, new york, 426 p. doi: 10.1017/cbo9780511535529 ordóñez, s., calvo, j.p., garcía-del-cura, m.a., alonso-zarza, a.m. & hoyos, m. (1991): sedimentology of sodium sulphate deposits and special clays from the tertiary madrid basin (spain).– spec. publs int. ass. sediment., 13, 39–55. doi: 10.1002/9781444303919.ch2 pandža, m., franjić, j. & škvorc, ž. (2007): the salt marsh vegetation on the east adriatic coast.– biologia, 62, 24–31. doi: 10.2478/s11756-007-0003-x pandžić, k. & likso, t. (2005): eastern adriatic typical wind field patterns and largescale atmospheric conditions.– int. j. climatol., 25, 81–98. doi: 10.1002/joc.1085 pedersen, t.f., waters, r.d. & macdonald, r.w. (1989): on the natural enrichment of cadmium and molybdenum in the sediments of ucluelet inlet, british columbia.– sci. total environ., 79/2, 125–139. doi: 10.1016/0048-9697(89)90357-4 g eo lo gi a c ro at ic a geologia croatica 72/140 peh, z. & kovačević galović, e. (2014): geochemistry of istrian lower palaeogene bauxites — is it relevant to the extent of subaerial exposure during cretaceous times?– ore geol. rev., 63, 296–306. doi: 10.1016/j.oregeorev.2014.05.020 peh, z. & kovačević galović, e. (2016): geochemistry of lower palaeogene bauxites – a unique signature for the tectonostratigraphic evolution of part of the croatian karst.– geol. croat., 69/2, 269–279. doi: 10.4154/gc.2016.24 pikelj, k., žigić, v. & juračić, m. (2009): origin and distribution of surface sediments in the grgur channel, adriatic sea, croatia.– geol. croat., 62, 95–105. doi: 10.4154/gc.2009.08 pikelj, k. (2010): sastav i porijeklo sedimenata dna istočne strane jadranskog mora.– unpubl. phd thesis, faculty of science, university of zagreb, 247 p. pikelj, k. & juračić, m. (2013): eastern adriatic coast (eac): geomorphology and coastal vulnerability of a karstic coast.– j. coast. res., 289, 944–957. doi: 10. 2112/jcoastres-d-12-00136.1 popadić, a., vidović, j., ćosović, v., medaković, d., dolenec, m. & felja, i. (2013): impact evaluation of the industrial activities in the bay of bakar (adriatic sea, croatia): recent benthic foraminifera and heavy metals.– mar. pollut. bull., 76/1–2, 333–248. doi: 10.1016/j.marpolbul.2013.09.039 regan, k & nadilo, b. (2010): crkveno graditeljstvo, stare crkve na cresu i lošinju te okolnim otocima.– građevinar, 62/2, 151–161. reimann, c., filzmoser, p., garrett, r.g. & dutter, r. (2008): statistical data analysis explained: applied environmental statistics with r.– john wiley & sons, ltd., 343 p. doi: 10.1002/9780470987605 rock, n.m.s. (1988): lecture notes in earth sciences, 18: numerical geology.– springer verlag, berlin, 427 p. romano, m., ferreyra, h., ferreyroa, g., molina, f. v., caselli, a., barberis, i., beldoménico, p. & uhart, m. (2016): lead pollution from waterfowl hunting in wetlands and rice fields in argentina.– sci. total. environ., 545–546, 104–13. doi: 10.1016/j.scitotenv.2015.12.075 schmidt, r., müller, j., drscher-schneider, r., krisai, r., szeroczynska, k. & barić, a. (2000): changes in lake level and trophy at lake vrana, a large karstic lake on the cres island (croatia).– j. limnol., 59/2, 113–130. schmidt, r., pugliese, n., müller, j., szeroczyńska, k., bogner, d., melis, r., kamenik, c., barič, a. & danielopol, d.l. (2001): palaeoclimate, vegetation and coastal lake development, from upper pleniglacial until early holocene, in the northern adriatic valun bay (isle of cres, croatia).– il quaternario, 14/1, 61–78. scholz, f., siebert, c., dale, a.w. & frank, m. (2017): intense molybdenum accumulation in sediments underneath a nitrogenous water column and implications for the reconstruction of paleo-redox conditions based on molybdenum isotopes.– geochim. cosmochim. acta, 213, 400–417. doi: 10.1016/j.gca.2017.06.048 schönfeld, j., alve, e., geslin, e., jorissen, f., korsun, s., spezzaferri, s. & members of the fobimo group (2012): the fobimo (foraminiferal bio-monitoring) initiative–towards a standardised protocol for softbottom benthic foraminiferal monitoring studies.– marine micropaleontology, 94–95, 1–13. sen gupta, b.k., smith, l.e. & machain-castillo, m.l. (2009): foraminifera of the gulf of mexico.– in: felder, d.l. & camp, d.k. (eds.): gulf of mexico-origins, waters, and biota. texas a&m university press, college station, texas, 87–129. sen gupta, b.k. (1999): foraminifera in marginal marine environments.– in: sen gupta, b.k. (eds.): modern foraminifera. kluwer academic publishers, dordrecht, boston, 141–159. doi: 10.1007/0-306-48104-9_9 serandrei barbero, r., carbognin, l., taroni, g. & cova, e. (1999): distribution of recent benthic foraminifera in the southern basin of the venice lagoon (italy): statistical evaluation of taxa significance.– micropaleontology, 45/1, 99–111. doi: 10.2307/1486205 serandrei barbero, r., albani, a.d. & bonardi, m. (2004): ancient and modern salt marshes in the lagoon of venice.– palaeogeogr. palaeoclimatol. palaeoecol., 202/3–4, 229–244. doi: 10.1016/s0031-0182(03)00636-9 sgarrella, f. & moncharmont zei, m. (1993): benthic foraminifera of the gulf of naples (italy): systematics and autoecology.– bollettino della societá paleontologica italiana, 32/2, 145–264. shaw, t.a., kirby, j.r., holgate, s., tutman, p. & plater, a.j. (2016): contemporary salt-marsh foraminiferal distribution from the adriatic coast of croatia and its potential for sea level studies.– j foraminifer res, 46/3, 314–332. doi: 10.2113/gsjfr.46.3.314 signell, r.p., chiggiato, j., horstmann, j., doyle, j.d., pullen, j. & askari, f. (2010): high-resolution mapping of bora winds in the northern adriatic sea using synthetic aperture radar.– j. geophys. res. ocean., 115, 1–20. doi: 10.1029/2009jc005524 sondi, i. & juračić, m. (2010): whiting events and the formation of aragonite in mediterranean karstic marine lakes: new evidence on its biologically induced inorganic origin.– sedimentology, 57/1, 85–95. doi: 10.1111/j.1365-3091.2009.01090.x sondi, i., mikac, n., vdović, n., ivanić, m., furdek, m. & škapin, s.d. (2017): geochemistry of recent aragonite-rich sediments in mediterranean karstic marine lakes: trace elements as pollution and palaeoredox proxies and indicators of authigenic mineral formation.– chemosphere, 168, 786–797. doi: 10.1016/j.chemosphere.2016.10.134 starkey, h.c. & blackmon, p.d. (1984): sepiolite in pleistocene lake tecopa, inyo county, california.– developments in sedimentology, 37, 137–147. stéphan, p., goslin, j., pailler, y., manceau, r., suanez, s., van vlietlanoë, b., hénaff, a. & delacourt, c. (2015): holocene salt-marsh sedimentary infilling and relative sea level changes in west brittany (france) using foraminifera-based transfer functions.– boreas, 44/1, 153–177. doi: 10.1111/bor. 12092 suokhrie, t., saraswat, r. & nigam, r. (2017): foraminifera as bio-indicators of pollution: a review of research over the last decade.– in: kathal, p.k., nigam, r. & talib, a. (eds.): micropaleontology and its applications.-scientific publishers (india), 265–284. surić, m. (2002): submarine karst of croatia evidence of former lower sea levels podmorski kras na hrvaškem dokaz o nekdanji nižji morski gladini.– acta carsologica, 31/3, 89–98. surić, m. (2005): submerged karst – dead or alive? examples from the eastern adriatic coast (croatia).– geoadria, 10/1, 5–19. statsoft, inc. (2011). statistica (data analysis software system), version 10. www. statsoft.com. šegota, t. & filipčić, a. (2003): köppenova podjela klima i hrvatsko nazivlje.– geoadria, 8/1, 17–37. šorša, a., peh, z. & halamić, j. (2018): geochemical mapping the urban and industrial legacy of sisak, croatia, using discriminant function analysis of topsoil chemical data.– j. geochem. explor., 187, 155–167. doi: 10.1016/j.gexplo.2017. 07.014 šparica, m., koch, g., belak, m., miko, s., šparica miko, m., viličić, d., dolenec, t., bergant, s., lojen, s., vreča, p., dolenec, m., ogrinc, n. & ibrahimpašić, h. (2005): recent sediments of makirina bay (northern dalmatia, croatia): their origin viewed through a multidisciplinary approach.– geol. croat., 58/1, 21–71. taher, a.g. (2001): geochemistry of recent marine sediments in the bardawil lagoon, northern sinai, egypt.– hydrobiologia, 457, 5–16. takata, h. (2006): foraminifera in an organic-rich, brackish-water lagoon, lake saroma, hokkaido, japan.– j. foraminifer. res., 36/1, 44–60. doi: 10.2113/36.1.44 tung, j.w.t. & tanner, p.a. (2003): instrumental determination of organic carbon in marine sediments.– marine chemistry, 80, 161–170. doi: 10.1016/s0304-4203 (02)00116-0 vaniček, v., juračić, m., bajrakterević, z. & ćosović, v. (2000): benthic foraminiferal assemblages in a restricted environment-an example from the mljet lakes (adriatic sea, croatia).– geol croat., 53/2, 269–280. vacchi, m., marriner, n., morhange, c., spada, g., fontana, a. & rovere, a. (2016): multiproxy assessment of holocene relative sea level changes in the western mediterranean: sea-level variability and improvements in the definition of the isostatic signal.– earth-science rev., 155, 172–197. doi: 10.1016/j. earscirev.2016.02.002 velde, b. (1995): composition and mineralogy of clay minerals.– in: velde, b. (eds.): origin and mineralogy of clays. springer verlag, berlin, heidelberg, new york, 8–42. vidović, j. (2010): analiza utjecaja prirodnih promjena i antropogenog djelovanja na zajednice foraminifera u sedimentima istočne obale jadranskog mora.– unpubl. phd thesis, faculty of science, university of zagreb, 218 p. vidović, j., ćosović, v., juračić, m. & petricioli, d. (2009): impact of fish farming on foraminiferal community, drvenik veliki island, adriatic sea, croatia.– mar pollut bull., 58/9, 1297–1309. doi: 10.1016/j.marpolbul.2009.04.031 vidović, j., dolenec, m., dolenec, t., karamarko, v. & žvab rožič, p. (2014): benthic foraminifera assemblages as elemental pollution bioindicator in marine sediments around fish farm (vrgada island, central adriatic, croatia).– mar pollut bull., 83/1, 198–213. doi: 10.1016/j.marpolbul.2014.03.051 waelbroek, c., labeyrie, l., michel, e., duplessy, j.c., mcmanus, j.f., lambeck, k., balbon, e. & labracherie, m. (2002): sea level and deep water temperature changes derived from benthic foraminifera isotopic records.– quaternary science reviews, 21, 295–305. doi: 10.1016/s0277-3791(01)00101-9 wunsam, s., schmidt, r. & muller, j. (1999): holocene lake development on two dalmatian lagoons (malo and veliko jezero, isle of mljet) in respect to changes in adriatic sea level and climate.– palaeogeography, palaeoclimatology, palaeoecology, 146, 251–281. doi: 10.1016/s0031-0182(98)00147-3 zaninović, k., gajić-čapka, m., perčec tadić, m., vučetić, m., milković, j., bajić, a., cindrić, k., cvitan, l., katušin, z., kaučić, d., likso, t., lončar, e., lončar, ž., mihajlović, d., pandžić, k., patarčić, m., srnec, l. & vučetić, v. (2008): klimatski atlas hrvatske / climate atlas of croatia 1961–1990., 1971–2000.– državni hidrometeorološki zavod, zagreb, 200 p. g eologia c roatica brunović et al.: holocene foraminiferal and geochemical records in the coastal karst dolines of cres island, croatia 41 plate 1. foraminifera specimens from marine ponds: 1-3 trochammina inflata (montagu), 1 spiral side, 2 umbilical side, 3 spiral side with deflated chambers; 4-6 haplophragmoides canariensis (d’orbigny), 4 side view, 5 face view, 6 side view; 7 side view; 7-11 ammonia tepida (cushman), 7 deformed specimen, 8 umbilical view, 9 enlargement of the test surface with diatoms, 10 enlargement of the test surface. g eo lo gi a c ro at ic a geologia croatica 72/142 plate 2. foraminifera specimens from the jaz and sonte embayments: 1 peneroplis planatus (fichtel & moll) side view; 2 elphidium aculeatum (d’orbigny) side view; 3 cribroelphidium gerthi (van voorthuysen) side view; 4 buccella sp.2 umbilical side; 5 rosalina macropora (hofker) spiral side; asterigerinata mamilla (williamson) spiral side; 7 haynesina depressula (walker & jacob) side view; 8 bolivina striatula (cushman) side view; 9 bolivina pseudoplicata (heron-allen & earland) side view. errata corrige volume 65, issue 3 article adriano banak, oleg mandic, marijan kovačić and davor pavelić: “late pleistocene climate history of the baranja loess plateau – evidence from the zmajevac loess – paleosol section (northeastern croatia)” needs corrections as follow: pg. 416, the explanation of figure 4 needs correction to: figure 4: 1. helicopsis striata, not helicopsis hungarica 2. discus ruderatus, not vallonia tenuilabris 3. bradybaena fruticum, not vitrea contracta 4. chondrula tridens, not helicopsis striata 7. mastus bielzi, not chondrula tridens new figure 4 is included: pg. 417, left column, sixteenth line: the sentence needs correction: “helicopsis striata and arianta arbustorum are present in all horizons (fig. 5 except for l4 and l5).” pg. 417, the explanation of table 2 needs correction: second line in table regarding helicopsis hungarica should be erased. instead, mastus bielzi should be put discus ruderatus instead vallonia tenuilabris in fourth line. bradybaena fruticum instead vitrea contracta in twelfth line. mastus bielzi (kimakowicz, 1890) m sh w central and se european discus ruderatus (hartmann, 1821) cr d w eurosiberian bradybaena fruticum (müller, 1774) t h o european pg. 418, figure 5 needs correction: vertical names of species should be corrected. mastus bielzi instead of helicopsis hungarica; discus ruderatus instead of vallonia tenuilabris; bradybaena fruticum instead of vitrea contracta. new figure 5 is included: pg. 418, left column, eight line: the sentence needs correction: “thermophilous and mesophilous species are dominant in terms of paleotemperature (74–55% abundance, fig. 5), although warm-climate representatives, typical for interglacial periods, such as helicigona banatica or discus perspectivus have bee observed.” additional sentence is needed and follows previous: “only mastus bielzi was determined.” pg. 418, right column, fifth line: the sentence needs correction: insert after ….ložek (1964).: “in zmajevac profile some differences are present in form of mixed helicopsis striata/arianta arbustorum and helicopsis striata/pupilla loessica faunas. “also in contrast to irig, two lowermost samples in zmajevac bear cooler climate representatives in form of columella columella fauna reflecting the middle pleistocene penultimate glacial (mis6) conditions.” pg. 418, right column, twenty third line: sentence needs to be inserted: “negligible percentage of bradybaena fruticum species is present in samples from zmajevac profile, so homonymous assemblage type could not be determined.” pg. 420, left column, second line: sentence needs correction: “the middle part of the horizon produced a helicopsis striata assemblage with common discus ruderatus (6.59%).” pg. 420, left colum, twelfth line: sentence needs correction: “along with pupilla sp., discus ruderatus is also abundand (11%).” 2018 | 71/3 | 173 – 184 | 6 figs. | 2 tabs. | 3 app. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction an important task in groundwater studies is the estimation of ground­water­mixing­ratios­and­identification­of­the­associated­ processes­in­order­to­effectively­protect­the­groundwater­from­the­ negative­impact­of­mixing­processes.­furthermore,­there­is­an­ urgent­need­to­study­the­spatial­distribution­of­mixing­processes­ and­it­is­sensible­to­reveal­the­admixture­of­groundwater,­both­in­ terms­of­quantity­and­quality­of­these­resources.­these­processes­ can­include­groundwater­and­river­interaction­(beyerle­et­al.,­ 1999),­submarine­discharge­or­the­formation­of­brines­(burnett­et­al.,­2010),­geothermal­activity­(han­et­al.,­2010),­and­ interactions­between­aquifers­(rueedi­et­al.,­2005).­the­mixing­ ratio­from­different­groundwater­parameters­can­be­estimated­if­ the­mixed­waters­have­distinct­chemical­and/or­isotopic­composition­signatures­and­also­using­hydrogeochemical­models­(mass­ balance­and­reaction-path­models).­ the­above­studies­of­mixing­ratios­were­calculated­mainly­ based­on­the­usefulness­of­only­one­or­two­parameters.­the­use­ of­only­a­couple­of­parameters­produces­reliable­results­which­ can­be­applied­when­the­a­priori­information­about­the­groundwater­system­is­readily­known.­actually,­there­are­several­conditions­that­can­result­in­inaccurate­estimation­of­the­mixing­ratio­ i.e.,­sparse­information­about­the­groundwater­system,­a­heterogeneous­database­of­chemical­and­isotopic­data­and­high­spatial­ estimating groundwater mixing ratios from vertical flux processes due to excessive groundwater pumping using hydrogeochemical parameters and nitrate concentrations in the bandung basin, indonesia ahmad taufiq1,2, takahiro hosono1,5, irwan iskandar3, agus j. effendi4 and lambok m. hutasoit2 1kumamoto university, graduate school of science and technology, kumamoto, japan; (correspondence author email address: ahmad.taufiq@pu.go.id) 2faculty of earth science and technology, bandung institute of technology, bandung, indonesia 3faculty of mining and petroleum engineering, bandung institute of technology, bandung, indonesia 4faculty of civil and environmental engineering, bandung institute of technology, bandung, indonesia 5priority organization for innovation and excellence, kumamoto university, kumamoto, japan doi: 10.4154/gc.2018.19 abstract one crucial task in groundwater research and management is the estimation of groundwater mixing ratios. here, estimations of mixing ratios are presented systematically and spatially for shallow and deep groundwater in some areas of excessive groundwater pumping with different magnitudes of groundwater drawdown. the mixing ratios are estimated using two methods: (1) the total mixing ratio using all parameters, and (2) the mixing ratio using nitrate concentrations. the values for the total mixing ratio indicate that mixing between the shallow and the deep groundwater clearly occurs in all three depression areas, but with different ratios. the spatial distribution map of the total mixing ratio clearly shows that the largest mixing ratio occurs near the center of the cone of depression, and that the ratio decreases gradually away from the center of the depression area. there is a positive correlation among total mixing ratios, cfc-12 concentrations, and modeled vertical flux. remarkably, the highest correlation is found between the correlation of the total mixing ratio and magnitude of vertical flux in the largest drawdown area. meanwhile, comparison of the mixing ratio calculations by the different methods showed insignificant correlation which means nitrate is ineffective as the prevailing contaminant tracer for deep groundwater in this basin. overall, this study concludes that the method of total mixing ratio using all chemical parameters is the most effective and consistent with previous methods. this study provides further proof that groundwater mixing between the shallow and deep groundwater systems has clearly occurred in the bandung basin as an impact of excessive groundwater pumping. variations­of­the­end-members.­under­these­conditions,­it­would­ be­worth­basing­the­calculation­of­total­mixing­ratios­on­all­the­ available­parameters­measured­because­the­uncertainty­of­estimation­can­be­reduced­(rueedi­et­al.,­2005).­­ nowadays,­industrialization,­urbanization,­and­population­ growth­has­created­a­host­of­environmental­hazards,­reflected­in­ subsurface­environmental­problems­(foster­&­chilton,­ 2003).­moreover,­in­asian­cities­as­very­rapidly­developing­areas,­ subsurface­environmental­problems­are­mostly­caused­by­excessive­groundwater­pumping,­groundwater­drawdown­and­groundwater­contamination­(taniguchi­et­al.,­2008;­jago-on­et­al.,­ 2009;­hosono­et­al.,­2011).­specifically,­in­indonesia,­a­significant­groundwater­drawdown­has­been­reported­throughout­big­ cities­such­as­jakarta,­bandung,­and­semarang,­starting­from­increasing­of­water­demand­ leading­ to­ excessive­groundwater­ pumping­(wirakusumah­&­danaryanto,­2004).­this­ excessive­groundwater­pumping­could­result­in­mixing­processes­ between­groundwaters­from­different­systems­or­aquifers.­ ­it­ might­cause­dilution­of­the­groundwater,­with­the­potential­to­ cause­the­degradation­of­groundwater­quality.­­ in­the­bandung­basin,­human­and­industrial­activities­have­ influenced­the­groundwater­condition.­since­the­early­1970s,­ many­textile­industrial­activities­have­taken­place­in­the­bandung­ basin.­industrialization,­along­with­urbanization­has­caused­a­ article history: manuscript received june 30, 2017 revised manuscript accepted september 28, 2018 available online october 24, 2018 keywords: excessive pumping; groundwater mixing; mixing ratio; nitrate isotopes; bandung basin, indonesia g eo lo gi a c ro at ic a geologia croatica 71/3174 significant­increase­in­water­demand­in­the­bandung­basin­with­ the­biggest­groundwater­consumer­being­the­textile­industries.­ consequently,­there­are­three­large­groundwater­depression­areas­ within­these­industrial­and­urban­areas,­which­have­different­ magnitudes­of­groundwater­drawdown.­in­the­study­area,­excessive­groundwater­pumping­has­created­a­vertical­downward­flux­ from­the­shallow­to­deeper­aquifers,­which­has­caused­groundwater­mixing­in­those­areas.­mixing­was­indicated­by­observed­ high­cfc-12­concentrations­in­deep­groundwater­and­the­vertical­ flux­was­confirmed­by­modeling­(taufiq­et­al.,­2017).­ to­further­evaluate­mixing­in­the­groundwater,­it­is­necessary­to­calculate­mixing­ratios­that­can­be­achieved­using­hydrogeochemical­parameters.­furthermore,­it­is­also­necessary­to­increase­our­understanding­of­the­mixing­process,­and­to­further­ prove­that­there­was­groundwater­mixing­due­to­excessive­pumping­in­the­bandung­basin.­in­this­paper,­the­calculation­of­mixing­ ratios­between­shallow­and­deep­groundwater­will­be­presented­ systematically­and­spatially.­in­the­first­part­of­this­paper,­the­total­mixing­ratio­will­be­determined­by­involving­all­measured­ parameters­to­eliminate­possible­observer­bias­and­reduce­estimation­uncertainty.­meanwhile,­in­the­second­part,­the­mixing­ ratio­will­be­calculated­by­involving­only­one­parameter,­nitrate,­ as­a­contaminant­tracer.­for­further­evaluation­of­groundwater­ mixing,­the­estimated­mixing­ratios­will­be­compared­for­three­ depression­areas.­the­results­are­also­compared­with­results­from­ previous­investigations.­finally,­the­two­methods­of­calculating­ mixing­ratios­will­be­evaluated­both­scientifically­and­practically.­ 2. study area bandung­basin­is­located­in­the­centre­of­west­java,­indonesia­ and­is­one­of­the­most­developed­basins­in­indonesia.­bandung­ is­the­capital­of­west­java­province,­the­most­densely­populated­ province­in­indonesia,­and­the­centre­of­its­textile­industry.­the­ bandung­basin­has­an­area­of­about­2300­km2,­includes­five­administrative­regions,­and­currently­has­a­population­of­more­than­ 7­million­people.­the­basin­is­surrounded­by­mountains­up­to­ 2400­m­high,­consisting­of­late­tertiary­and­quaternary­volcanic­deposits,­forming­an­intramontane­basin.­the­geology­of­this­ basin­is­classified­into­the­following­three­formations,­oldest­first­ (hutasoit,­2009):­cikapundung­formation,­cibereum­formation­and­kosambi­formation­(figure­1).­the­oldest­cikapundung­formation­is­composed­of­conglomerates,­and­compacted­ breccia,­tuff,­and­andesite­lava­and­forms­the­basement­of­the­ groundwater­basin.­the­overlying­cibeureum­formation­is­a­ fan-shaped­distribution­of­volcanic­deposit­of­late­pleistocene– holocene­age.­the­youngest­kosambi­formation­is­distributed­ in­the­centre­of­this­basin,­as­a­lake­deposit,­and­its­lithology­ consists­of­unconsolidated­claystone,­siltstone,­and­sandstone­of­ holocene­age. hydrogeologically,­the­bandung­basin­can­be­divided­into­ two­groundwater­systems:­a­shallow­one­and­a­deep­groundwater­ system.­the­shallow­groundwater­is­found­in­the­kosambi­formation­or­the­unconfined­aquifer­with­a­local­flow­that­is­accessed­ from­dug­wells­with­depths­much­less­than­20­m.­meanwhile,­the­ deep­groundwater­is­allied­with­the­cibeureum­formation­as­a­ semiconfined­and­confined­aquifer­with­an­intermediate­and­regional­flow.­it­is­accessed­via­drilled­wells­mainly­in­­the­industrial­area­with­well­depths­exceeding­40­m.­to­calculate­mixing­ amounts,­it­is­assumed­that­there­is­a­mixture­of­water­from­the­ two­aquifer­systems:­shallow­and­deep­groundwaters­in­the­depression­areas­due­to­excessive­pumping­of­this­basin.­there­are­ three­large­groundwater­depression­areas­in­the­industrial­­complex:­ cimahi­area­(cmhi),­rancaekek­area­(rck),­and­dayeuhkolot­ area­(dhyk)­(figure­1b),­that­are­well-known­by­their­codes­as­ the­investigation­areas.­monitoring­of­the­deep­groundwater­levels­ was­accomplished­by­the­basin­authority:­the­office­of­energy­ and­mineral­resources,­west­java­province.­the­results­show­ that­for­the­deep­groundwater­potential­over­the­past­twenty­years­ the­cmhi­area­has­the­largest­rate­of­groundwater­drawdown­decline:­1–2­m/year,­the­rck­area­is­declining­at­a­rate­of­0–1­m/ year,­and­the­dhyk­area­is­declining­at­a­slightly­lower­rate­stil.­ according­ to­taufiq­et­al.­ (2017),­ the­groundwaters­ in­ the­ bandung­basin­could­be­determined­based­on­their­hydrogeochemical­types,­which­are:­a­ca-hco3­type­for­the­shallow­aquifer­ and­a­na-hco3­type­for­the­deep­groundwater.­but­there­were­ some­seemingly­random­occurrences­of­the­ca-hco3­type­in­the­ deep­groundwater­at­three­depression­areas­that­were­identified­ as­the­result­of­groundwater­mixing.­ figure 1. location map of the sampling points plotted on a geological map (hutasoit, 2009): a) for shallow groundwater, b) for deep groundwater. the points with potential contours (taufiq et al., 2017) and the locations of their end-members. the shallow groundwater flows from the periphery to the centre of the basin meanwhile, the deep groundwater was identified where there were three depression areas: cmhi area, rck area and dhyk area. g eologia c roatica taufiq et al.: estimating groundwater mixing ratios from vertical flux processes due to excessive groundwater pumping ... 175 3. methodology 3.1. sampling and methods in­this­study,­all­the­hydrogeochemical­data­were­used­for­the­ shallow­and­deep­groundwater­that­have­been­obtained­for­determining­water­composition­in­the­bandung­basin­(taufiq­et­al.,­ 2017)­(appendix­1).­a­total­of­40­shallow­and­65­deep­groundwater­samples­were­collected­between­may­to­july­2015.­­some­ in-situ­tests,­such­as­temperature,­ph,­dissolved­oxygen­(do),­ electrical­conductivity­(ec),­and­oxidation–reduction­potential­ (orp)­of­the­water­samples­were­measured­in­the­field­with­d­ quality­minimal­atmospheric­contact,­using­a­portable­meter­of­ wm-32ep­(toa-dkk­co,­tokyo­japan).­water­samples­were­ collected­separately­for­each­analytical­procedure­(methods­detailed­in­taufiq­et­al.,­2017):­major­ions­(na+,­k+,­ca2+,­mg2+,­ cl-,­so4 2-­and­hco3 -)­and­stable­isotopes­(δ18o­and­δ2h).­for­ some­trace­element­concentrations,­fe2+­and­mn2+­concentrations­ were­analyzed­using­an­inductively­coupled­plasma­mass­spectrometer­(icp-ms)­(nexion300d,­perkinelmer,­usa)­and­using­ standard­mode­and­kinetic­energy­discrimination­(ked)­mode.­ replicate­analyses­were­carried­out­to­check­the­precision­and­ accuracy­of­the­results.­precision­was­better­than­±10­%,­evaluated­from­the­repeated­measurement­of­standard­reference­solutions­with­certified­concentrations. for­analysis­of­nitrate­concentrations­and­nitrate­isotope­ratios,­water­samples­were­also­collected­separately­(methods­detailed­in­hosono­et­al.,­2013;­2014):­nitrate­concentration­was­ measured­by­ion­chromatography­(dionex­ics­1600,­thermo­ fisher­scientific­inc.,­usa);­and­the­nitrate­isotope­compositions­ were­determined­following­the­denitrifier­method­of­sigman­et­ al.­(2001)­and­casciotti­et­al.­(2002).­using­this­method,­a­ sample­containing­nitrate­was­converted­to­nitrous­oxide­(n2o)­ by­denitrifying­bacteria­that­lack­n2o-reductase­activity.­this­ was­then­stripped­from­the­sample­vial­using­helium­carrier­gas,­ purified­using­cryogenic­trapping­(thermo­fisher­precon­system),­chromatographically­separated­(thermo­fisher­gas­bench),­ and­analyzed­using­mass­spectrometry­(thermo­fisher­delta­v­ advantage).­ isotope­values­were­calibrated­using­ the­united­ states­geological­society­(usgs)­and­international­atomic­energy­agency­(iaea)­nitrate­standards:­usgs-34,­usgs-35,­and­ iaea-n3.­based­on­replicate­measurements­of­standards­and­ samples­(n­¼­288),­the­analytical­precisions­for­δ15n-no3 and δ18o-no3 -­were­better­than­±0.2­0/00­and­±0.3­0/00,­respectively.­ the­nitrogen­isotope­ratio­for­powdered­samples­was­determined­ by­mass­spectrometry­interfaced­with­a­cns­elemental­analyzer­ (thermo­fisher­flash­2000).­the­analytical­precision­of­the­analysis­was­better­than­±­0.15­0/00. 3.2. calculation method of the mixing ratio nomenclature c­­concentration­­ m­­mixing­ratio­of­a­parameter­i p­­groundwater­parameter­­ n­­ total­number­of­parameters­ s­­sample­ w­­weight­of­parameter­ σ­ standard­deviation­ the­calculation­of­mixing­ratios­in­this­study­was­applied­using­ some­equations­from­the­following­procedures­(rueedi­et­al.,­ 2005;­han­et­al.,­2010).­firstly,­the­calculation­used­all­the­parameters­(s)­for­two­end-members:­end-member­1­for­shallow­ groundwater­(c1)­and­end-member­2­for­deep­groundwater­(c2).­ the­end­members­were­the­most­representative­samples­which­ had­natural­groundwater­quality.­­the­two­previous­studies­were­ considered­that­had­characterized­natural­groundwater­in­the­ bandung­basin.­as­mentioned­by­wagner­&­sukrisno­ (1998)­and­taufiq­et­al.­(2017),the­shallow­groundwater­was­ characterized­generally­as­an­ca-hco3-type,­generally­low­oxygen­levels,­elevated­fe2+­concentration,­elevated­mn2+­concentrations,­ ­ and­high­cfc-12­concentration,­meanwhile­ the­deep­ groundwater­was­characterized­generally­by­the­na-hco3-type,­ with­elevated­cl–­concentrations­and­no­cfc-12­concentration. the­estimation­began­by­calculating­the­mixing­ratio­(mp) for­every­concentration­(c)­of­each­parameter­(p)­using­an­equation­ (1).­ the­ equations­ (1)­ –­ (4)­were­ applied­ by­ following­ rueedi­et­al.­(2005); m c c c c p s p p p p = , , , , 2 1 2 (1)­ at­every­parameter,­its­standard­deviation­(σp) was estimated using­equation­(2); s s s sp p p s p p p p s p p p c c c c c c c= -( ) -( ) + -( ) +1 1 2 2 2 1 2 2 1 2 2 2 2 2 , , , , , , , , , ss p pc, , -( )1 2 ­(2) the­total­mixing­ratio­(m m w w p n p p p n p = = = å å 1 1 )­was­calculated­by­averaging­the­ ratios­of­all­parameters­(n)­using­equation­(3),­and­the­usefulness­ of­each­parameter­or­the­weight­(wp)­using­equation­(4); m m w w p n p p p n p = = = å å 1 1 (3) w p p = 1 2s (4) next,­the­mixing­ratio­was­estimated­using­only­one­parameter­and­only­using­equation­(1).­the­parameter­was­nitrate­concentration,­selected­considering­its­nitrate­isotopes,­the­stable­ isotope­ratios­of­nitrogen­and­oxygen.­it­was­selected­because­the­ nitrate­concentration­is­an­ongoing­contaminant­in­this­basin.­ moreover,­since­the­1970s,­nitrate­isotopes­are­a­powerful­tracer­ for­revealing­concealed­contaminant­sources­(i.e.­kreitler,­ 1979;­kaplan­&­magaritz,­1986;­hosono­et­al.,­2013).­­ the­possible­source­of­nitrate­could­be­identified­from­groups­of­ isotope­composition­ranges,­using­the­approach­of­kendall,­ (1998)­and­singleton­et­al.­(2007):­group­a­(the­nitrification­ of­nh4 +­in­fertilizer;­−8­to­+5­‰,­−5­to­+15­‰,­for­δ15n-no3 and δ18o-no3 -,­respectively);­group­b­(soil­nitrogen;­+3­to­+8­‰,­−5­ to­+15­‰);­group­c­(manure­and­sewage-derived­no3 -:­0­to­+25­ ‰,­−5­to­+15­‰);­group­d­(fertilizer­;­−5­to­+8­‰,­+15­to­+25­ ‰),­group­e­(precipitation­;­−5­to­+10­‰­and­+18­to­+70­‰),­respectively­(figure­5a). results 4.1. selection of end members firstly,­two­end-members­were­selected,­one­for­shallow­groundwater­and­one­for­deep­groundwater,­based­on­assumptions­of­ their­major­differences­in­terms­of­hydrogeochemical­signatures­ and­based­on­the­groundwater­system­of­the­study­area.­the­two­ end-members­for­the­dual­groundwater­system­in­the­bandung­ basin­were:­ end-member­1­–­shallow­groundwater.­this­groundwater­ was­characterized­by­elevated­ca2+­concentrations­of­approximately­50­mg/l,­elevated­hco3 –­concentrations­of­approximately­ 200­mg/l,­low­na+ concentrations­around­35­mg/l,­k+­concentrations­around­10­mg/l,­mg2+­concentrations­round­15­mg/l,­low­ cl–­and­ low­concentrations­of­around­40­mg/l­ (wagner­&­ sukrisno,­1998).­the­ca2+­concentration­and­cfc-12­conceng eo lo gi a c ro at ic a geologia croatica 71/3176 trations­in­shallow­groundwater­were­higher­than­in­the­deep­ groundwater­(taufiq­et­al.,­2017).­ end-member­2­–­deep­groundwater.­this­groundwater­was­ characterized­by­elevated­na+ concentrations­of­approximately­ 50­mg/l,­elevated­mg2+­concentrations­around­20­mg/l,­elevated­ cl–­concentrations­of­around­45­mg/l,­and­hco3 –­concentrations­ of­about­250­mg/l,­low­ca2+­concentrations­around­40­mg/l,­low­ k+­concentrations­around­10­mg/l­(wagner­&­sukrisno,­ 1998).­low­or­negative­values­for­orp­(oxidation-reduction­ ­potential)­and­no­cfc-12­concentrations­(taufiq­et­al.,­2017)­ mean­that­this­groundwater­is­characterized­by­either­reducing­ conditions­of­the­confined­aquifer­or­that­the­water­is­old­and­uncontaminated.­ notably,­persistent­contaminants­or­‘unnatural’­substances­ that­affect­the­major­chemistry­or­isotopic­groundwater­signature­ were­excluded­from­the­definition­of­the­natural­parameters.­according­to­wagner­&­sukrisno­(1998):­the­shallow­groundwater­had­elevated­fe2+concentration­if­it’s­values­exceed­1­mg/l­ (defined­as­elevated­substance­1)­and­mn2+­concentration­if­it’s­ values­exceed­0.5­mg/l­(defined­as­elevated­substance­2).­meanwhile,­according­to­taufiq­et­al.­(2017):­the­shallow­groundwater­had­elevated­levels­of­cfc-12­concentration­if­this­exceeds­ >576­pptv­(defined­as­elevated­substance­3)­and­for­ the­deep­ groundwater,­it­had­elevated­substances­if­cfc-12­concentrations­ were­observed,­as­a­young­(modern)­tracer.­in­addition,­nitrate­ concentration­was­also­identified­as­elevated­substance­4.­since­ there­was­a­study­about­its­natural­background­values,­the­cut-off­ level­of­3­mg/l­was­chosen­based­on­the­observations­in­the­bandung­basin­(taufiq­et­al.,­2018). the­selection­of­end­members­was­undertaken­by­taking­ samples­that­had­no­unnatural­substances­and­were­located­at­the­ furthest­point­possible­from­a­potential­contaminant­source­for­ every­depression­areas.­­the­shallow­groundwater­sample­was­ the­closest­location­to­the­recharge­area­or­the­periphery­of­this­ basin­and­the­deep­groundwater­was­the­furthest­location­from­ the­depression­area­or­industrial­area.­­a­sample­number­s7­was­ chosen­as­end-member­1­(from­4­samples)­because­its­location­ was­the­closest­to­the­northern­area;­and­d46­for­end-member­2­ figure 2. the spatial distribution map of the total mixing ratios for all samples of deep groundwater in the depression areas: cmhi area (a), rck area (b), and dhyk area (c). the points with potential contours from observation wells (taufiq et al., 2017). g eologia c roatica taufiq et al.: estimating groundwater mixing ratios from vertical flux processes due to excessive groundwater pumping ... 177 (from­15­samples)­because­it­was­located­furthest­away­from­the­ depression­area.­selection­of­end­members­in­the­cmhi­area­is­ presented­in­table­1,­and­plotted­in­figure­1.­using­the­same­approach­for­the­rck­and­dhyk­areas,­s12­and­s11­were­selected­ as­end-members­of­the­shallow­and­groundwater­samples­respectively;­and­d27­and­d30a­as­end­members­of­deep­groundwater­ samples.­the­selection­of­ the­end­members­for­ the­rck­and­ dhyk­area­is­presented­in­appendix­1.­ 4.2. calculation of the total mixing ratio to­calculate­the­total­mixing­ratio,­all­the­above­equations­were­ applied.­the­calculation­was­ideal­for­estimating­the­total­mixing­ ratio­because­it­used­all­the­important­parameters,­7­major­ions,­ and­2­stable­isotopes.­the­calculated­total­mixing­ratios­vary­ from­0.01­to­0.69.­these­results­indicate­that­there­was­mixing­in­ deep­groundwater­due­to­a­recharging­vertical­flux­from­the­shallower­to­the­deeper­waters.­in­the­cmhi­area,­the­mean­of­the­ total­mixing­ratio­was­0.43­which­is­larger­than­the­other­areas.­ the­results­are­presented­in­appendix­2,­plotted­in­figure­3a­and­ summarized­in­table­2. the­spatial­distribution­pattern­of­mixing­ratios­shows­a­clear­ relationship­to­the­contour­pattern­of­the­depression­areas­(as­presented­in­figure­2).­the­spatial­distribution­map­of­the­total­mixing­ratio­in­the­cmhi­area­clearly­shows­that­a­larger­mixing­ratio­was­found­close­to­the­center­of­the­depression­cone,­and­the­ mixing­ratio­gradually­decreases­towards­the­edges­of­the­cone.­ this­pattern­was­also­observed­in­the­rck­and­dhyk­areas,­but­ is­less­pronounced.­­it­is­due­to­the­biggest­vertical­flux­of­water­ occurring­at­the­centre­of­the­cone,­meaning­that­the­deepest­­ drawdown­causes­subsequent­groundwater­mixing­between­shallow­and­deep­aquifers.­thus,­the­gradual­decrease­to­the­edge­of­ the­depression­zone­is­also­spatially­controlled­by­the­depth­of­ drawdown.­the­mixing­pattern­ in­ the­cmhi­area­where­ the­ greatest­drawdown­occurred­is­more­spatially­related­to­the­cone­ of­depression­than­for­the­other­areas. 4.3. calculation of the nitrate mixing ratio the­range­of­nitrate­concentrations­is­between­0.20­and­20.69­ mg/l;­none­of­the­analyzed­samples­(n­=­93)­exceeded­the­world­ health­organization­limit­of­50­mg/l­for­both­the­shallow­and­ deep­groundwaters­in­this­basin,­but­some­of­the­shallow­groundwaters­exceeded­indonesia’s­standard­of­10­mg/l.­notably,­in­the­ bandung­basin,­the­shallow­groundwater­tended­to­be­more­nitrate­enriched­than­the­deep­one,­as­depicted­in­figure­4.­this­ enriched­trend­of­both­groundwaters­will­be­compared­in­detail­ in­a­future­paper­(taufiq­et­al.,­2018­in­press).­ figure 3. correlation between (a) magnitude of cfc-12 concentrations and the total mixing ratio, (b) magnitude of the vertical flux and the total mixing ratio. the variously colored dashed lines indicate the regression line of each correlation for each area. figure 4. distribution maps of nitrate concentrations for (a) shallow groundwater and (b) deep groundwater plotted on a land use map (bakorsortanal, 2009). g eo lo gi a c ro at ic a geologia croatica 71/3178 ta bl e 1. h yd ro ge oc he m ic al d at a in cl ud in g th ei r e nd m em be rs (c m h i a re a) . a) s ha llo w g ro un dw at er                                 sa m pl in g n o (s x) 7 m aj or io ns 2 st ab le is ot op es in sit u te st n itr at e iso to pe s id en tifi ed c on ta m in an ts n ot e ca 2+ m g2 + n a+ k+ h co 3cl so 4δ1 8o δ2 h d o o rp δ1 8o n o 3 δ1 5n n o 3(1 ) f e (2 ) m n (3 ) cf c12 (4 ) n o 3 m g/ l m g/ l m g/ l m g/ l m g/ l m g/ l m g/ l (0 /0 0) (0 /0 0)   m v (0 /0 0) (0 /0 0) pp b pp b pp tv m g/ l 7 75 .5 0 9. 10 16 .7 0 8. 15 27 6. 67 5. 80 90 .1 5 -5 .2 6 -4 3. 97 4. 28 85 .0 0 5. 7 10 .2 0. 99 0. 19 50 2 3. 99 en d m em be r 1 1 38 .2 2 11 .0 5 42 .2 6 10 .6 3 27 7. 38 20 .2 4 9. 00 -5 .1 6 -4 2. 97 4. 86 90 .0 0 2. 0 21 .6 7. 29 0. 23 24 9 5. 04   2 38 .1 0 11 .0 0 42 .4 4 10 .6 7 27 8. 66 20 .4 4 8. 70 -5 .1 6 -4 2. 97 3. 73 90 .0 0 9. 7 22 .8 10 .8 5 17 .4 9 43 7 5. 04   3 38 .8 9 12 .2 4 46 .7 8 6. 54 22 7. 16 13 .4 9 41 .7 7 -5 .3 1 -4 3. 51 4. 11 95 .7 5 -1 2. 2 15 .8 6. 92 11 .4 0 23 0 12 .0 9 co nt am in at ed (4 ) 31 55 .1 1 15 .4 5 28 .2 2 11 .6 6 17 6. 23 77 .4 5 10 3. 60 -5 .4 6 -4 4. 89 5. 66 10 0. 00 19 .9 14 .3 1. 41 0. 37 16 4 4. 00   9 51 .1 3 18 .0 9 23 .8 7 9. 44 12 1. 08 44 .0 8 87 .2 1 -6 .9 1 -4 2. 83 5. 01 84 .0 0 -1 .5 9. 6 2. 30 0. 59 76 8 10 .4 3 co nt am in at ed (3 .4 ) 28 42 .0 0 16 .7 3 60 .2 1 9. 87 17 6. 23 47 .2 2 1. 39 -4 .2 0 -3 8. 43 1. 92 26 .4 0 3. 4 9. 0           4 51 .0 0 18 .1 2 23 .9 8 9. 50 12 1. 1 44 .3 5 87 .2 0 -6 .9 1 -4 2. 83 5. 77 19 1. 00 -1 .5 9. 6 2. 62 19 .3 2 76 9 2. 28 co nt am in at ed (3 .4 ) 5 65 .1 0 25 .4 5 27 .5 3 11 .4 5 17 6. 35 77 .5 7 10 4. 71 -5 .4 0 -3 5. 00 6. 67 10 2. 00 2. 4 11 .0 1. 43 0. 33 57 9 9. 97 co nt am in at ed (3 ) 27 61 .1 0 25 .4 5 37 .4 4 11 .4 0 17 6. 33 77 .1 2 10 4. 23 -5 .4 0 -3 5. 00 4. 72 20 7. 00 1. 3 7. 1 0. 97 3. 91 59 5 3. 95 co nt am in at ed (3 ) 13 56 .6 0 18 .5 4 76 .0 8 34 .4 3 37 1. 45 91 .0 6 32 .5 1 -5 .3 5 -4 5. 00 2. 08 11 6. 00 3. 1 9. 3 2. 54 6. 48 40 4. 78   b) d ee p gr ou nd w at er                                 sa m pl in g n o (d x) 7 m aj or io ns 2 st ab le is ot op es in sit u te st n itr at e iso to pe s id en tifi ed c on ta m in an ts n ot e ca 2+ m g2 + n a+ k+ h co 3cl so 4δ1 8o δ2 h d o o rp δ1 8o n o 3 δ1 5n n o 3(1 ) f e (2 ) m n (3 ) cf c12 (4 ) n o 3 m g/ l m g/ l m g/ l m g/ l m g/ l m g/ l m g/ l (0 /0 0) (0 /0 0)   m v (0 /0 0) (0 /0 0) pp b pp b pp tv m g/ l 10 60 .2 23 .2 33 .5 8. 7 28 0. 9 21 .2 13 .8 -6 .2 -4 6. 8 4. 1 79 .0 20 .7 16 .5 na na 40 5. 2 1. 3   1 23 .8 10 .7 16 .9 7. 8 18 4. 7 4. 0 8. 6 -5 .5 -4 4. 2 3. 8 92 .0 38 .0 28 .7 na na 0. 0 1. 6   9 59 .9 22 .9 32 .6 7. 5 27 5. 2 20 .8 12 .7 -5 .4 -3 8. 3 2. 1 51 .2 20 .7 16 .5 na na 0. 0 1. 4   2 28 .0 13 .0 24 .0 9. 3 21 9. 2 9. 8 14 .5 -6 .2 -4 6. 6 5. 2 25 .5     na na 32 1. 6 1. 1 co nt am in at ed (3 ) 5a 28 .8 12 .8 23 .8 9. 3 21 7. 4 8. 8 14 .5 -6 .2 -4 5. 6 2. 5 48 .1 15 .6 18 .4 na na 0. 0 3. 0 co nt am in at ed (4 ) 3 27 .9 13 .9 23 .9 9. 2 21 7. 9 9. 8 15 .2 -5 .6 -4 4. 8 2. 1 66 .9     na na 12 9. 5 1. 1 co nt am in at ed (3 ) 5 68 .1 26 .7 86 .3 14 .9 29 5. 7 10 4. 6 54 .0 -5 .9 -4 5. 5 4. 3 39 .3 15 .4 18 .0 na na 31 4. 7 1. 9 co nt am in at ed (3 ) 8 59 .9 23 .1 32 .5 7. 4 27 9. 5 20 .9 13 .4 -5 .5 -4 4. 2 2. 1 96 .0 38 .0 28 .7 na na 0. 0 4. 0 co nt am in at ed (4 ) 6c 43 .9 18 .9 30 .9 9. 9 28 8. 4 21 .7 21 .9 -5 .7 -4 4. 7 2. 3 75 .7     na na 18 6. 3 1. 2 co nt am in at ed (3 ) 6 57 .0 24 .1 63 .1 11 .5 20 6. 7 45 .2 25 .2 -4 .7 -3 9. 9 2. 1 -1 0. 8 13 .6 19 .8 na na 29 2. 7 3. 2 co nt am in at ed (1 , 4 ) 4 29 .0 13 .2 24 .9 9. 5 21 9. 4 10 .0 15 .5 -6 .1 -4 6. 5 3. 4 31 .2 21 .2 16 .5 na na 24 3. 0 1. 1 co nt am in at ed (3 ) 4a 55 .8 23 .8 62 .5 10 .9 20 5. 4 44 .2 24 .1 -6 .1 -4 6. 5 3. 0 -6 8. 5 21 .4 16 .1 na na 0. 0 1. 1   6b 45 .2 19 .3 32 .6 10 .5 29 0. 5 21 .9 22 .4 -5 .6 -4 4. 6 5. 8 61 .3     na na 11 7. 9 1. 2 co nt am in at ed (3 ) 6a 44 .9 19 .2 31 .9 10 .2 28 9. 8 20 .7 21 .9 -5 .6 -4 4. 6 1. 9 71 .9     na na 80 .0 0. 2 co nt am in at ed (3 ) g eologia c roatica taufiq et al.: estimating groundwater mixing ratios from vertical flux processes due to excessive groundwater pumping ... 179 7c 45 .2 18 .8 32 .6 10 .5 29 0. 5 21 .9 22 .4 -6 .1 -4 6. 3 2. 7 17 .0 -4 .8 -2 .7 na na 16 9. 2 5. 3 co nt am in at ed (3 , 4 ) 7 60 .8 21 .0 73 .6 11 .2 38 6. 9 31 .8 98 .1 -5 .9 -4 0. 7 3. 0 -6 0. 4 20 .0 13 .0 na na 14 3. 1 4. 1 co nt am in at ed (3 , 4 ) 7b 60 .1 24 .0 33 .7 9. 9 28 5. 8 21 .9 13 .8 -6 .0 -4 0. 8 2. 7 14 .0 11 .9 16 .5 na na 12 6. 6 3. 6 co nt am in at ed (3 , 4 ) 7a 60 .6 20 .8 72 .9 11 .1 38 5. 1 30 .4 97 .9 -5 .9 -4 0. 8 6. 3 -4 4. 1 20 .7 18 .0 na na 86 .7 3. 6 co nt am in at ed (3 , 4 ) 47 25 .1 11 .1 31 .6 8. 9 25 3. 5 4. 0 4. 0 -6 .5 -4 5. 5 2. 8 12 4. 6 6. 6 8. 9 na na 23 .2 0. 4 co nt am in at ed (3 ) 46 24 .8 11 .1 31 .2 8. 9 25 0. 8 3. 9 5. 9 -6 .0 -4 5. 5 3. 2 11 0. 0 20 .1 12 .6 na na 0. 0 0. 3 en d m em be r 2 45 60 .8 13 .0 73 .7 10 .9 38 8. 5 32 .0 90 .8 -6 .2 -4 5. 6 2. 8 -3 0. 3 21 .2 19 .1 na na 0. 0 1. 7   12 37 .9 19 .7 22 .0 10 .5 30 5. 2 7. 8 9. 1 -6 .0 -4 6. 7 3. 1 38 .7 8. 9 18 .0 na na   2. 8   12 d 39 .0 18 .7 23 .1 11 .8 28 0. 7 8. 6 9. 3 -4 .6 -3 8. 3 2. 0 -3 2. 0     na na 0. 0 3. 0 co nt am in at ed (4 ) 12 f 38 .9 19 .9 22 .9 12 .0 29 9. 9 8. 1 9. 2 -5 .4 -4 2. 5 2. 3 -6 0. 4 33 .7 38 .3 na na 0. 0 3. 0 co nt am in at ed (4 ) 1 37 .2 15 .7 25 .0 8. 9 26 7. 8 2. 0 4. 6 -5 .4 -4 2. 5 4. 3 64 .4     na na 0. 0 3. 0 co nt am in at ed (4 ) 15 79 .3 34 .6 18 8. 3 18 .6 58 3. 3 14 1. 3 1. 6 -5 .5 -4 4. 9 3. 5 -1 4. 0 -1 .5 6. 0 na na 25 5. 3 0. 2 co nt am in at ed (3 ) 15 a 23 .8 8. 9 78 .7 9. 1 30 2. 8 43 .8 2. 7 -6 .8 -4 4. 0 2. 4 31 .2     na na 11 6. 6 2. 6 co nt am in at ed (3 ) 34 23 .3 8. 6 75 .5 9. 1 30 0. 7 42 .6 2. 6 -6 .0 -4 2. 6 2. 3 -6 0. 4 18 .9 12 .4 na na 0. 0 0. 4   39 b 24 .2 9. 6 78 .5 8. 8 30 2. 7 43 .4 2. 5 -6 .5 -4 2. 2 3. 2 50 .6 8. 5 25 .8 na na 0. 0 2. 5   so ur ce d at a: m aj or io ns , s ta bl e iso to pe s i ns itu te st (t au fi q e t a l., 20 18 a) ; f e2 +, m n2 + an d n itr at e iso to pe s ( th is st ud y)               table 2. summary of the statistical analysis from the calculated mixing ratios. a) cmhi area         descriptive statistic cfc-12 concentration*) vertical flux*) total mixing ratio nitrate mixing ratio mean 188.24 169,544 0.43 0.29 standard error 26.48 20,299 0.05 0.10 median 156.17 178,186 0.49 0.26 standard deviation 105.91 81,195 0.19 0.26 range 382.04 296,752 0.68 0.78 minimum 23.20 4,008 0.01 0.00 maximum 405.24 300,760 0.69 0.78 n 16 16 16 7 b) rck area         mean 114.80 201,819 0.15 0.29 standard error 25.72 41,518 0.03 0.11 median 100.34 235,762 0.12 0.13 standard deviation 92.72 155,347 0.10 0.30 range 290.34 464,918 0.27 0.77 minimum 11.72 11,262 0.00 0.02 maximum 302.06 476,180 0.27 0.79 n 13 15 15 7 c) dhyk area         mean 211.29 161,058 0.12 0.29 standard error 41.63 91,076 0.04 0.12 median 247.21 29,543 0.04 0.19 standard deviation 117.74 340,774 0.16 0.29 range 346.06 1,303,381 0.46 0.70 minimum 17.73 101 0.00 0.00 maximum 363.78 1,303,482 0.46 0.70 n 8 14 14 6 *) data from taufiq et al. (2017) the­nitrogen­isotope­ratios­of­the­possible­source­materials­ revealed­unique­signatures­with­some­compositional­variations.­ the­δ15nno3­of­groundwater­samples­ranged­from­−1.2­‰­to­ 47‰,­and­δ18ono3­ranged­from­−12.2­‰­to­33.7­‰.­differences­ in­isotopic­composition­between­the­shallow­and­deep­groundwater­were­not­discovered,­possibly­due­to­the­most­likely­and­ predominant­source­of­nitrate­contamination­in­the­investigated­ areas­being­septic­waste­leakage­(group­c)­from­the­urban­area.­ for­the­purpose­of­this­research­to­investigate­groundwater­ mixing­in­the­study­areas,­only­nitrate­concentrations­in­the­three­ cone-of-depression­areas­were­focused­on.­notably,­only­deep­ groundwater­containing­cfc-12­concentrations­were­selected­ which­implies­either­that­it­was­recharged­from­shallow­(younger)­ groundwater­(taufiq­et­al.,­2017)­or­that­the­nitrate­was­also­ possibly­recharged­from­the­shallow­groundwater.­according­to­ kendall­(1998)­and­singleton­et­al.­(2007)­the­nitrate­in­ these­areas­can­be­identified­from­the­following­potential­source­ groups:­a­(3­samples),­b­(13­samples),­c­(34­samples),­and­d­(5­ samples),­presented­in­appendix­3­and­figure­5.­in­addition,­deep­ groundwater­samples­with­low­do­values­(<­2­mg/l)­were­omitted­because­of­the­significant­denitrification­that­preferentially­ occurs­(böhlke­et­al.,­2002).­the­deep­groundwater­samples­ in­the­depression­cone­areas­appeared­to­have­been­recharged­ from­shallow­groundwater­that­contained­septic­tank­waste­and/ or­manure­waste­(group­c,­as­mentioned­in­section­3.2),­so­only­ these­samples­in­group­c­were­used­to­determine­the­nitrate­mixing­ratios.­ g eo lo gi a c ro at ic a geologia croatica 71/3180 the­nitrate­mixing­ratios­were­calculated­using­only­equation­(1)­with­the­same­end-members­as­the­total­mixing­ratio­calculation­(section­4.2).­the­calculated­nitrate­mixing­ratios­were­ between­0.01­and­0.78.­the­calculated­mixing­ratios­for­nitrate­ indicate­ that­ the­mixing­ between­ the­ shallow­ and­ the­ deep­ groundwater­clearly­occurs­in­all­three­depression­areas,­but­with­ different­ratios.­both­the­differences­in­nitrate­mixing­ratios­and­ total­mixing­ratios­reflect­the­variation­in­magnitude­of­the­flux­ from­shallower­to­deeper­groundwaters­and­are­controlled­by­the­ degree­of­drawdown­from­pumping.­the­results­are­presented­in­ appendix­3.,­plotted­in­figure­3b.­and­summarized­in­table­2. 5. discussion for­further­evaluation­of­groundwater­mixing­between­the­shallow­and­deep­groundwaters­caused­by­excessive­pumping,­the­ calculated­total­mixing­ratios­were­compared­with­other­earlier­ results­of­taufiq­et­al.­(2018a).­the­first­discussion­involves­the­ relationship­between­the­total­mixing­ratio­with­2­previous­methods:­between­the­magnitude­of­cfc-12­concentrations,­when­ it­is­used­as­a­hydrogeochemical­tracer­and­the­magnitude­of­vertical­flux­as­determined­by­modeling­(table­2;­taufiq­et­al.,­ 2017).­the­last­discussion­involves­a­comparison­of­calculation­ of­mixing­ratios­using­all­the­parameters­against­using­only­one­ parameter. the­total­mixing­ratios­had­a­positive­significant­correlation­ (p­<­0.05,­n­=­14)­with­the­magnitude­of­vertical­flux­(figure­3a)­ as­determined­by­modeling­in­all­of­the­three­depression­areas,­ but­there­was­a­lower­positive­significant­correlation­with­the­ magnitude­of­cfc-12­concentrations­(p­>­0.05,­n­=­14)­(figure­ 3b).­they­had­different­coefficients­of­correlation­for­each­depression­area.­remarkably,­the­highest­significant­correlation­was­ found­between­the­correlation­of­the­total­mixing­ratio­and­magnitude­of­vertical­flux­in­the­cmhi­area­(r­=­0.81,­p­<­0.01,­n­=­16).­ the­cmhi­area,­with­the­largest­groundwater­drawdown,­had­ the­highest­mean­total­mixing­ratio,­cfc-12­concentrations­and­ vertical­flux.­the­other­two­areas­followed­a­similar­pattern­but­ with­a­lower­mean­value.­this­indicates­that­the­method­of­the­ total­mixing­ratio­is­as­effective­as­the­two­other­methods,­the­ hydrogeochemical­tracer­and­the­modeling,­in­revealing­groundwater­mixing.­ the­two­methods­of­calculating­mixing­ratio­were­compared­ to­show­the­relationship­between­using­all­parameters­with­using­ only­one­selected­parameter.­the­comparison­of­calculating­mixing­ratio­by­using­all­parameters­and­by­using­only­nitrate­(figure­ 6)­shows­a­positive­correlation­(p­>­0.05,­n­=­6).­the­cmhi­area­ had­the­largest­total­mixing­ratio­and­also­the­largest­nitrate­ mixing­ratio­with­the­highest­coefficient­of­correlation­(r­=­0.36,­ figure 5. nitrate isotope comparison with possible source groups according to (a) the method of kendall (1998) for groundwater samples of (b) the cmhi, (c) the rck and (d) the dhyk areas. figure 6. correlation between the total mixing ratio and the nitrate mixing ratio for the three depression areas. varicolored dashed lines indicate the regression line of each correlation for each area. g eologia c roatica taufiq et al.: estimating groundwater mixing ratios from vertical flux processes due to excessive groundwater pumping ... 181 p­>­0.05,­n­=­7).­­the­same­positive­correlation­was­found­in­all­ other­areas,­the­rck­and­the­dhyk­areas,­but­with­lower­correlation­coefficients.­nitrate­mixing­ratios­had­a­larger­standard­ error­(se­=­0.10-0.12)­than­the­total­mixing­ratios­(se­=­0.03-0.05)­ for­all­depression­areas­(table­2).­the­total­mixing­ratio­shows­a­ better­fit­in­correlation­with­physical­parameters­than­the­nitrate­ mixing­ratio­does,­suggesting­that­nitrate­is­ineffective­as­a­prevailing­contaminant­tracer­in­this­basin.­it­might­be­because­ nitrate­in­deep­groundwater­were­controlled­by­many­factors.­ therefore,­these­results­corroborate­the­findings­of­previous­work­ (rueedi­et­al.,­2005)­which­shows­that­estimations­using­all­ ­parameters­could­reduce­the­uncertainty.­ 6. conclusions the­two­methods­for­calculating­mixing­ratios­were:­(1)­using­all­ the­parameters­and­(2)­using­only­nitrate,­presented­for­three­depression­areas­in­the­bandung­basin­which­have­different­magnitudes­of­groundwater­drawdown­(the­cmhi,­rck,­and­dhyk­ areas).­the­values­for­total­mixing­ratios­indicate­that­mixing­between­the­shallow­and­deep­groundwaters­clearly­occurs­in­all­ three­depression­areas,­but­with­different­ratios.­this­means­that­ the­mixing­processes­from­shallower­to­deeper­groundwater­occurred­in­areas­with­different­ratios­according­to­the­major­compositions.­the­area­with­the­largest­drawdown­had­the­biggest­ value­of­the­total­mixing­ratio.­in­addition,­the­spatial­distribution­ map­of­total­mixing­ratios­clearly­shows­that­the­largest­ratio­occurs­near­the­centre­of­the­cone­of­depression,­and­decreases­ gradually­outwards­away­from­the­centre. a­positive­correlation­was­found­between­total­mixing­ratios,­ cfc-12­concentrations,­and­the­magnitude­of­vertical­flux.­this­ correlation­indicates­that­estimating­the­total­mixing­ratio­is­as­ effective­as­using­cfc-12­concentrations­and­vertical­flux­modeling­for­revealing­groundwater­mixing­caused­by­the­shallow­ groundwater­that­recharges­the­deep­groundwater.­remarkably,­ the­highest­significant­correlation­is­found­between­the­correlation­of­the­total­mixing­ratio­and­magnitude­of­vertical­flux­in­the­ cmhi­area.­a­comparison­of­calculating­the­mixing­ratio­using­ all­the­parameters­and­using­nitrate­only­showed­a­less­positive­ correlation­thus­nitrate­is­an­ineffective­tracer­for­prevailing­contaminants­for­deep­groundwaters­in­this­basin.­the­nitrate­mixing­ratio­also­has­a­larger­standard­error­than­the­result­of­total­ mixing­ratio,­therefore­these­results­show­that­estimations­using­ all­parameters­could­reduce­the­uncertainty.­overall,­this­study­ concludes­that­the­method­of­total­mixing­ratio­using­all­chemical­parameters­is­the­most­effective,­can­reduce­the­uncertainty­ and­is­consistent­with­the­method­using­physical­parameters. acknowledgement we­would­like­to­express­gratitude­to­emeritus­professor­dr.­jun­ shimada­(kumamoto­university)­for­valuable­suggestions­and­ discussion.­ references bakorsotanal­(2009):­land­use­map,­sub­bandung­region,­scale­1:­50.000.­agency­of­geospatial­information:­republic­of­indonesia. beyerle,­u.,­aeschba,­c.h.,­hertig,­w.,­hofer,­m.,­ imboden,­d.m.,­ baur,­h.­&­kipfer,­r.­(1999):­infiltration­of­river­water­to­a­shallow­aquifer­ investigated­with­3h/3he,­noble­gases­and­cfcs.–­journal­of­hydrology,­220,­ 169–185. böhlke,­j.k.,­wanty,­r.,­tuttle,­m.,­delin,­g.­&­landon,­m.­(2002):­ denitrification­in­the­recharge­area­and­discharge­area­of­a­transient­agricultural­ nitrate­plume­in­a­glacial­outwash­sand­aquifer,­minnesota.–­water­resource­research,­38,­10–26. burnett,­w.c,­peterson,­r.n,­santos,­i.r.­&­hicks,­r.w.­(2010):­use­of­automated­radon­measurements­for­rapid­assessment­of­groundwater­flow­into­florida­streams.–­journal­of­hydrology,­380,­issues­3–4,­298–304.­doi:­10.1016/j. jhydrol.2009.11.005 casciotti,­k.l.,­sigman,­d.m.,­galanter­h.m.,­böhlke,­j.k.­&­hilkert,­ a.­(2002):­measurement­of­the­oxygen­isotopic­composition­of­nitrate­in­seawater­ and­freshwater­using­the­denitrifier­method.–­analytical­chemistry,­74,­4905–4912. foster,­s.s.d.­&­chilton,­p.j.­ (2003):­groundwater:­ the­process­ and­global­ significance­of­aquifer­degradation.­philosophical­transactions­of­the­royal­society­of­london.–­biological­sciences,­358,­1957–1972. han,­d.h.,­liang,­x.,­jin,­m.g.,­currell,­m.j.,­song,­x.f.­&­liu,­c.m­(2010):­ evaluation­of­groundwater­hydrochemical­characteristics­and­mixing­behavior­in­ the­daying­and­qicun­geothermal­systems,­xinzhou­basin.–­journal­of­volcanology­and­geothermal­research,­189,­92–104.­doi:­10.1016/j.jvolgeores.2009.10.011 hosono,­t.,­delinom,­r.,­nakano,­t.,­kagabu,­m.,­&­shimada,­j.­(2011):­ evolution­model­of­δ34s­and­δ18o­in­dissolved­sulfate­in­volcanic­fan­aquifers­from­ recharge­to­coastal­zone­and­through­the­jakarta­urban­area,­indonesia.–­science­ of­the­total­environment,­409,­2541–2554. hosono,­t.,­tokunaga,­t.,­kagabu,­m.,­nakata,­h.,­orishikida,­t.,­lin,­ i.­&­shimada,­j­(2013):­the­use­of­δ15n­and­δ18o­tracers­with­an­understanding­ of­groundwater­flow­dynamics­for­evaluating­the­origins­and­attenuation­mechanisms­of­nitrate­pollution.–­water­research,­47,­2661–2675. hosono,­t.,­tokunaga,­t.,­tsushimaa,­a.­&­shimada,­j.­(2014):­combined­ use­of­δ13c,­δ15n,­and­δ34s­tracers­to­study­anaerobic­bacterial­processes­in­groundwater­flow­systems.–­water­research,­­54,­284–296. hutasoit,­l.m.­(2009):­groundwater­condition­of­bandung­area,­with­and­without­ artificial­recharge:­numerical­simulation­results.–­indonesian­journal­on­geoscience,­4,­1777–188­(in­indonesian).­ jago-on,­k.a.b.,­kaneko,­s.,­fujikura,­r.,­fujiwara,­a.,­imai,­t.,­matsumoto,­t.,­zhang,­j.,­tanikawa,­h.,­tanaka,­k,,­lee,­b.,­&­taniguchi­m.­(2009):­urbanization­and­subsurface­environmental­issues:­an­attempt­ at­dpsir­model­application­in­asian­cities.–­science­of­the­total­environment,­ 407,­308–310.­doi:­10.1016/j.scitotenv.2008.08.004 kaplan,­n.­&­magaritz,­m.­(1986):­a­nitrogen-isotope­study­of­the­sources­of­ nitrate­contamination­in­groundwater­of­the­pleistocene­coastal­plain­aquifer,­israel.–­water­research,­20,­131–135.­doi:­10.1016/0043-1354(86)90002-3 kendall,­c.­(1998):­tracing­nitrogen­sources­and­cycling­in­catchments.–­in:­kendall,­c.­&­mcdonnell,­j.j.­(eds.):­isotope­tracers­in­catchment­hydrology.­ elsevier.­science­b.v.,­amsterdam,­519–576.­doi:­10.1016/b978-0-444-815460.50023-9 kreitler,­c.w.­(1979):­nitrogen-isotope­ratio­studies­of­soils­and­groundwater­nitrate­ from­alluvial­fan­aquifers­in­texas.–­journal­of­hydrology,­42,­147–170. rueedi,­j.,­purtschert,­r.,­beyerle,­u.,­alberich,­c.­&­kipfer,­r.­(2005):­ estimating­groundwater­mixing­ratios­and­their­uncertainties­using­a­statistical­ multi­parameter­approach.–­journal­of­hydrology,­305,­1–14.­doi:­10.1016/j.jhydrol.2004.06.044 sigman,­d.m.,­casciotti,­k.l.,­andreani,­m.,­barford,­c.,­galanter,­ m.­&­böhlke,­j.k.­(2001):­a­bacterial­method­for­the­nitrogen­isotopic­analysis­ of­nitrate­in­seawater­and­freshwater.–­analytical­chemistry,­73,­145–153.­doi:­ 10.1021/ac010088e singleton,­m.j.,­esser,­b.k.,­moran,­j.e.,­hudson,­g.b.,­mcnab,­w.w.­&­ harter,­t.­(2007):­saturated­zone­denitrification:­potential­for­natural­attenuation­of­nitrate­contamination­in­shallow­groundwater­under­dairy­operations.–­environmental­science­and­technology,­41,­759–765.­doi:­10.1021/es061253g taniguchi,­m.,­shimada,­j.,­fukuda,­y.,­yamano,­m.,­onodera,­s.,­ kaneko,­s.­&­yoshikoshi,­a.­(2009):­anthropogenic­effects­on­the­subsurface­thermal­and­groundwater­environments­in­osaka,­japan­and­bangkok,­thailand.–­science­of­the­total­environment,­407,­3153–3164.­doi:­10.1016/j.scitotenv.2008.06.064 taufiq,­a.,­hosono,­t.,­ide,­k.,­kagabu­m.,­iskandar,­i.,­effendi a.j.,­ hutasoit, l.m.­&­shimada,­j.­(2017):­impact­of­excessive­groundwater­ pumping­on­rejuvenation­age­processes­in­the­bandung­basin,­indonesia­as­determined­by­hydrogeochemistry­and­modeling.–­hydrogeology­journal,­26,­1263– 1279.­doi:­10.1007/s10040-017-1696-8 taufiq,­­a.,­ ­effendi,­­a.j.,­ ­iskandar,­­i.,­­hosono,­­t.­­&­­hutasoit,­ ­l.m.­ (2018):­­controlling­factors­­and­­driving­mechanisms­nitrate­­contamination­­in­ groundwater­­system­of­­bandung­­basin­,­indonesia,­deduced­by­combined­use­of­ stable­isotope­ratios,­cfc­age­dating,­and­socioeconomic­parameters.–­water­ ­research­­journal.­https://doi.org/10.1016/j.watres.2018.10.049­(article­in­press). wagner,­w.­&­sukrisno,­x.­(1998):­natural­groundwater­quality­and­groundwater­ contamination­in­the­bandung­basin,­indonesia.–­indonesia­bulletin­of­environmental­geology,­23. wirakusumah,­a.d.­&­danaryanto,­h.­(2004):­groundwater­management­in­ indonesia­case­study:­groundwater­conservation­in­jakarta,­bandung­and­semarang.­41st­coordinating­committee­for­geoscience­programmes­in­east­and­southeast­asia­(ccop)­(tsukuba,­japan). g eo lo gi a c ro at ic a geologia croatica 71/3182 a)­shallow­groundwater­ 1.1­cmhi­area ca2+ mg2+ na+ k+ hco3 clso4 δ18o δ2h do orp δ18ono3 δ15nno3 (1)­fe (2)­mn (3)­cfc-12 (4)­no3 mg/l mg/l mg/l mg/l mg/l mg/l mg/l (0/00) (0/00) mv (0/00) (0/00) ppb ppb pptv mg/l 7 75.50 9.10 16.70 8.15 276.67 5.80 90.15 -5.26 -43.97 4.28 85.00 5.7 10.2 0.99 0.19 502 3.99 end­member­1 1 38.22 11.05 42.26 10.63 277.38 20.24 9.00 -5.16 -42.97 4.86 90.00 2.0 21.6 7.29 0.23 249 5.04 contaminated­(4) 2 38.10 11.00 42.44 10.67 278.66 20.44 8.70 -5.16 -42.97 3.73 90.00 9.7 22.8 10.85 17.49 437 5.04 contaminated­(4) 3 38.89 12.24 46.78 6.54 227.16 13.49 41.77 -5.31 -43.51 4.11 95.75 -12.2 15.8 6.92 11.40 230 12.09 contaminated­(4) 31 55.11 15.45 28.22 11.66 176.23 77.45 103.60 -5.46 -44.89 5.66 100.00 19.9 14.3 1.41 0.37 164 4.00 contaminated­(4) 9 51.13 18.09 23.87 9.44 121.08 44.08 87.21 -6.91 -42.83 5.01 84.00 -1.5 9.6 2.30 0.59 768 10.43 contaminated­(3.4) 28 42.00 16.73 60.21 9.87 176.23 47.22 1.39 -4.20 -38.43 1.92 26.40 3.4 9.0 4 51.00 18.12 23.98 9.50 121.1 44.35 87.20 -6.91 -42.83 5.77 191.00 -1.5 9.6 2.62 19.32 769 2.28 contaminated­(3) 5 65.10 25.45 27.53 11.45 176.35 77.57 104.71 -5.40 -35.00 6.67 102.00 2.4 11.0 1.43 0.33 579 9.97 contaminated­(3) 27 61.10 25.45 37.44 11.40 176.33 77.12 104.23 -5.40 -35.00 4.72 207.00 1.3 7.1 0.97 3.91 595 3.95 contaminated­(3) 13 56.60 18.54 76.08 34.43 371.45 91.06 32.51 -5.35 -45.00 2.08 116.00 3.1 9.3 2.54 6.48 40 4.78 contaminated­(4) 1.2­rck­area ca2+ mg2+ na+ k+ hco3 clso4 δ18o δ2h do orp δ18ono3 δ15nno3 (1)­fe (2)­mn (3)­cfc-12 (4)­no3 mg/l mg/l mg/l mg/l mg/l mg/l mg/l (0/00) (0/00) mv (0/00) (0/00) ppb ppb pptv mg/l 30a 55.52 14.47 48.05 13.50 310.20 16.80 29.21 -6.23 -48.49 4.70 99.51 8.1 14.4 63.60 1.49 21 1.08 12 53.82 17.82 61.17 8.96 283.58 33.46 34.28 -4.87 -41.83 3.90 130.00 33.1 12.0 4.16 5.60 12 2.97 end­member­1 30 55.57 14.85 48.38 13.63 310.86 16.75 29.16 -6.22 -48.47 3.97 147.79 3.37 1.69 20.69 contaminated­(4) 29 53.43 17.59 61.67 8.93 283.96 33.79 34.60 -5.01 -43.21 3.21 132.74 17.9 39.1 1.15 1.68 7.62 contaminated­(4) 26 53.99 17.60 58.06 8.80 283.76 33.50 34.66 -4.88 -41.84 0.00 3.6 7.3 0.40 0.23 1.06 20 55.52 14.47 48.05 13.50 310.20 16.80 29.21 -6.22 -48.47 3.71 173.00 8.1 14.4 3.65 26.37 21 1.08 24 53.90 17.60 61.06 8.90 283.80 33.42 34.45 -5.53 -47.98 4.24 174.00 5.2 19.5 0.00 0.09 12 1.97 21a 19.60 10.98 60.10 5.75 251.89 52.30 1.84 -4.87 -41.83 6.61 90.00 15.0 12.1 6.79 58 1.25 23 58.20 22.80 69.70 16.40 385.80 91.20 18.90 -3.94 -41.48 2.47 87.00 18.2 47.0 1.04 4.67 56 1.65 16 61.20 19.71 89.39 27.20 423.13 111.29 24.52 -4.92 -41.46 4.16 107.00 15.4 21.0 70.79 9.52 85 5.75 contaminated­(4) 13 56.60 18.54 76.08 34.43 371.45 91.06 32.51 -5.35 -45.00 2.08 116.00 3.1 9.3 2.54 6.48 40 4.78 contaminated­(4) 1.3­dhyk­area ca2+ mg2+ na+ k+ hco3 clso4 δ18o δ2h do orp δ18ono3 δ15nno3 (1)­fe (2)­mn (3)­cfc-12 (4)­no3 mg/l mg/l mg/l mg/l mg/l mg/l mg/l (0/00) (0/00) mv (0/00) (0/00) ppb ppb pptv mg/l 15d 45.17 18.75 31.91 10.21 290.50 20.90 21.80 115 5.0 10.8 0.54 0.23 692.75 2.25 contaminated­(3) 6 55.10 15.45 28.31 11.66 176.23 77.45 104.90 -6.30 -44.07 3.7 124 5.5 12.9 0.00 1.06 327.29 3.87 contaminated­(4) 6a 62.04 23.14 31.05 6.35 168.44 86.60 43.31 -5.53 -39.00 5.2 192 4.5 16.9 45.73 1.99 9.06 3.42 contaminated­(4) 9 51.13 18.09 23.87 9.44 121.08 44.08 87.21 -5.91 -42.83 5.0 84 -1.5 9.6 2.30 0.59 767.92 10.43 contaminated­(3.4) 19 62.40 23.10 30.30 6.50 168.33 86.50 43.30 -4.49 -29.75 3.5 90 1.4 -1.2 0.21 0.10 250.33 3.33 contaminated­(4) 28 42.00 16.73 60.21 9.87 176.23 47.22 1.39 -4.20 -38.43 1.9 26 3.4 9.0 699.41 532.13 1.30 contaminated­(2) 18 55.01 15.34 29.11 11.41 176.98 77.30 104.60 -5.30 -44.07 3.5 125 5.5 12.9 0.01 0.64 1132.00 3.87 contaminated­(3,4) 31 17.65 6.55 11.70 3.52 130.20 4.10 9.60 -5.60 -35.61 4.6 125 0.67 0.14 1276.19 3.00 contaminated­(3,4) 10 76.64 9.17 16.99 8.18 280.69 6.00 90.10 -6.17 -46.77 4.0 68 25.2 30.5 0.72 1.62 646.69 1.67 contaminated­(3) 11 52.40 15.48 27.39 10.31 248.09 12.00 49.65 -5.19 -42.70 2.9 82 1.0 10.5 2.52 6.28 192.67 2.99 end­member­1 11a 52.50 15.45 27.10 10.31 247.89 11.00 49.50 -5.19 -42.70 1.8 162 6.4 18.7 18.36 144.18 646.69 9.02 contaminated­(3) elevated­substances note sampling­no­ (sx) 7­major­ions note sampling­no­ (sx) 7­major­ions 2­stable­isotopes insitu­test nitrate isotopes elevated­substances sampling­no­ (sx) 7­major­ions 2­stable­isotopes insitu­test nitrate isotopes 2­stable­isotopes insitu­test nitrate isotopes elevated­substances note b)­deep­groundwater ca2+ mg2+ na+ k+ hco3 clso4 δ18o δ2h do orp δ18ono3 δ15nno3 (3)­cfc-12 (4)­no3 mg/l mg/l mg/l mg/l mg/l mg/l mg/l (0/00) (0/00) mv (0/00) (0/00) pptv mg/l 10 60.2 23.2 33.5 8.7 280.9 21.2 13.8 -6.2 -46.8 4.1 79.0 20.7 16.5 405.2 1.3 1 23.8 10.7 16.9 7.8 184.7 4.0 8.6 -5.5 -44.2 3.8 92.0 38.0 28.7 0.0 1.6 9 59.9 22.9 32.6 7.5 275.2 20.8 12.7 -5.4 -38.3 2.1 51.2 20.7 16.5 0.0 1.4 2 28.0 13.0 24.0 9.3 219.2 9.8 14.5 -6.2 -46.6 5.2 25.5 321.6 1.1 contaminated­(1) 5a 28.8 12.8 23.8 9.3 217.4 8.8 14.5 -6.2 -45.6 2.5 48.1 15.6 18.4 0.0 3.0 contaminated­(4) 3 27.9 13.9 23.9 9.2 217.9 9.8 15.2 -5.6 -44.8 2.1 66.9 129.5 1.1 contaminated­(1) 5 68.1 26.7 86.3 14.9 295.7 104.6 54.0 -5.9 -45.5 4.3 39.3 15.4 18.0 314.7 1.9 contaminated­(1) 8 59.9 23.1 32.5 7.4 279.5 20.9 13.4 -5.5 -44.2 2.1 96.0 38.0 28.7 0.0 4.0 contaminated­(4) 6c 43.9 18.9 30.9 9.9 288.4 21.7 21.9 -5.7 -44.7 2.3 75.7 186.3 1.2 contaminated­(1) 6 57.0 24.1 63.1 11.5 206.7 45.2 25.2 -4.7 -39.9 2.1 -10.8 13.6 19.8 292.7 3.2 contaminated­(1,­4) 4 29.0 13.2 24.9 9.5 219.4 10.0 15.5 -6.1 -46.5 3.4 31.2 21.2 16.5 243.0 1.1 contaminated­(1) 4a 55.8 23.8 62.5 10.9 205.4 44.2 24.1 -6.1 -46.5 3.0 -68.5 21.4 16.1 0.0 1.1 6b 45.2 19.3 32.6 10.5 290.5 21.9 22.4 -5.6 -44.6 5.8 61.3 117.9 1.2 contaminated­(1) 6a 44.9 19.2 31.9 10.2 289.8 20.7 21.9 -5.6 -44.6 1.9 71.9 80.0 0.2 contaminated­(1) 7c 45.2 18.8 32.6 10.5 290.5 21.9 22.4 -6.1 -46.3 2.7 17.0 -4.8 -2.7 169.2 5.3 contaminated­(1,­4) 7 60.8 21.0 73.6 11.2 386.9 31.8 98.1 -5.9 -40.7 3.0 -60.4 20.0 13.0 143.1 4.1 contaminated­(1,­4) 7b 60.1 24.0 33.7 9.9 285.8 21.9 13.8 -6.0 -40.8 2.7 14.0 11.9 16.5 126.6 3.6 contaminated­(1,­4) 7a 60.6 20.8 72.9 11.1 385.1 30.4 97.9 -5.9 -40.8 6.3 -44.1 20.7 18.0 86.7 3.6 contaminated­(1,­4) 47 25.1 11.1 31.6 8.9 253.5 4.0 4.0 -6.5 -45.5 2.8 124.6 6.6 8.9 23.2 0.4 contaminated­(1) 46 24.8 11.1 31.2 8.9 250.8 3.9 5.9 -6.0 -45.5 3.2 110.0 20.1 12.6 0.0 0.2 end­member­2 45 60.8 13.0 73.7 10.9 388.5 32.0 90.8 -6.2 -45.6 2.8 -30.3 21.2 19.1 0.0 1.7 12 37.9 19.7 22.0 10.5 305.2 7.8 9.1 -6.0 -46.7 3.1 38.7 8.9 18.0 2.8 12d 39.0 18.7 23.1 11.8 280.7 8.6 9.3 -4.6 -38.3 2.0 -32.0 0.0 3.0 contaminated­(4) 12f 38.9 19.9 22.9 12.0 299.9 8.1 9.2 -5.4 -42.5 2.3 -60.4 33.7 38.3 0.0 3.0 contaminated­(4) 1 37.2 15.7 25.0 8.9 267.8 2.0 4.6 -5.4 -42.5 4.3 64.4 0.0 3.0 contaminated­(4) 15 79.3 34.6 188.3 18.6 583.3 141.3 1.6 -5.5 -44.9 3.5 -14.0 -1.5 6.0 255.3 0.2 contaminated­(1) 15a 23.8 8.9 78.7 9.1 302.8 43.8 2.7 -6.8 -44.0 2.4 31.2 116.6 2.6 contaminated­(1) 34 23.3 8.6 75.5 9.1 300.7 42.6 2.6 -6.0 -42.6 2.3 -60.4 18.9 12.4 0.0 0.4 39b 24.2 9.6 78.5 8.8 302.7 43.4 2.5 -6.5 -42.2 3.2 50.6 8.5 25.8 0.0 2.5 data­sources:­­major­ion,­stable­isotopes­and­insitu­test­data­(taufiq­et.­al.,­2017);­fe2+,­mn2+­and­nitrate­isotopes­(this­study).­ 2.1­cmhi­area sampling­no­ (dx) 7­major­ions 2­stable­isotopes insitu­test nitrate isotopes elevated­contaminants note appendix 1. data of all parameters for shallow and deep groundwater with their identified elevated substances g eologia c roatica taufiq et al.: estimating groundwater mixing ratios from vertical flux processes due to excessive groundwater pumping ... 183 ca2+ mg2+ na+ k+ hco3 clso4 δ18o δ2h do orp δ18ono3 δ15nno3 (3)­cfc-12 (4)­no3 mg/l mg/l mg/l mg/l mg/l mg/l mg/l (0/00) (0/00) mv (0/00) (0/00) pptv mg/l 23 21.5 8.3 10.5 2.3 157.2 2.0 3.2 -6.2 -51.5 4.3 147.2 6.4 12.9 3.2 contaminated­(4) 22a 39.2 9.2 13.5 5.0 160.8 0.6 1.1 -6.1 -41.0 5.3 130.9 34.6 40.8 120.7 2.0 contaminated­(1) 22 39.9 7.4 6.9 3.0 110.6 2.7 0.5 -6.3 -50.8 5.6 124.0 5.4 12.2 302.1 4.0 contaminated­(1,­4) 21 39.2 9.3 13.6 5.0 170.4 0.7 1.2 -6.3 -51.1 5.3 171.0 3.6 8.2 100.3 2.1 contaminated­(1) 33a 36.1 15.5 48.9 6.3 275.9 44.2 8.1 -5.8 -48.4 3.7 18.0 19.7 15.2 234.8 0.4 contaminated­(1) 25 36.3 14.9 48.2 6.5 280.1 44.1 8.7 -6.0 -48.9 5.5 134.6 3.8 5.7 238.4 0.5 contaminated­(1) 20 33.2 25.0 55.6 13.6 375.4 42.6 0.8 -5.4 -45.8 4.0 99.5 5.2 11.4 48.3 2.0 contaminated­(1) 24 25.2 14.1 16.8 7.1 233.1 1.3 6.4 -6.1 -48.8 3.2 132.7 4.7 8.7 11.7 0.5 contaminated­(1) 24b 25.2 14.1 16.1 7.1 230.2 1.2 6.3 -5.4 -45.8 4.0 159.0 5.2 11.4 105.7 0.2 contaminated­(1) 19c 38.0 18.1 50.8 7.8 298.3 60.7 0.6 -5.5 -47.0 2.2 5.0 18.6 14.6 68.1 0.3 contaminated­(1) 18a 46.5 19.2 110.5 9.1 375.4 121.7 2.7 -4.5 -42.8 4.4 -6.0 19.8 16.2 27.9 0.2 contaminated­(1) 20a 36.1 16.3 49.8 6.5 278.0 44.9 8.3 -5.8 -48.4 3.2 45.6 6.8 10.4 38.6 0.6 contaminated­(1) 19 27.1 11.5 63.6 9.3 321.6 23.5 0.3 -6.0 -41.7 3.3 8.0 18.6 14.6 156.8 0.3 contaminated­(1) 33 36.2 15.7 47.4 6.2 270.5 40.3 8.3 -5.8 -48.4 3.7 105.0 15.8 5.1 39.1 0.1 contaminated­(1) 27 42.4 19.9 30.2 5.7 323.4 26.0 2.0 -4.5 -42.8 7.0 -30.0 18.6 12.5 0.0 0.1 end­member­2 18 47.3 19.4 111.5 9.2 379.0 123.8 2.8 -5.1 -45.4 5.6 -15.2 10.4 16.5 0.0 0.2 19b 36.3 20.5 57.1 19.8 612.6 94.4 1.6 -6.1 -41.0 2.5 2.0 23.2 16.7 1.6 ca2+ mg2+ na+ k+ hco3 clso4 δ18o δ2h do orp δ18ono3 δ15nno3 (3)­cfc-12 (4)­no3 mg/l mg/l mg/l mg/l mg/l mg/l mg/l (0/00) (0/00) mv (0/00) (0/00) pptv mg/l 11 27.5 13.2 18.2 8.4 126.7 40.5 14.0 -6.1 -46.6 3.0 100.0 18.5 13.4 0.0 2.0 12 37.9 19.7 22.0 10.5 305.2 7.8 9.1 -6.0 -46.7 3.1 72.0 8.9 18.0 2.8 12a 38.8 19.9 22.3 11.9 305.5 8.0 9.1 -4.6 -38.3 3.1 38.7 3.0 contaminated­(4) 12d 39.0 18.7 23.1 11.8 280.7 8.6 9.3 -4.6 -38.3 2.0 -32.0 0.0 3.0 contaminated­(4) 12f 38.9 19.9 22.9 12.0 299.9 8.1 9.2 -5.4 -42.5 2.3 -60.4 33.7 38.3 0.0 3.0 contaminated­(4) 17 24.4 9.6 79.5 9.2 304.9 43.8 2.7 -5.5 -49.0 2.0 -32.0 20.1 17.8 46.0 2.6 contaminated­(1) 13 79.1 34.5 187.1 18.5 580.1 140.5 1.5 -5.8 -44.7 2.9 -5.2 0.0 3.8 contaminated­(4) 29a 16.2 7.4 162.7 22.6 395.7 40.5 6.4 -5.6 -43.8 2.0 0.0 19.4 21.3 1.3 29 16.2 7.5 162.6 22.6 395.0 40.2 6.2 -5.6 -43.8 5.0 -19.6 285.1 1.1 contaminated­(1) 30a 30.6 11.6 35.3 7.0 295.9 2.0 4.8 -5.7 -44.0 3.0 -42.2 20.1 13.4 0.0 0.9 end­member­2 43 38.2 15.2 99.8 11.3 324.3 74.4 1.8 -5.8 -40.7 3.9 -38.7 19.4 21.7 0.0 6.6 contaminated­(4) 28 33.2 13.5 53.1 10.3 308.5 27.0 6.4 -5.5 -42.9 3.5 -39.7 0.0 6.6 contaminated­(4) 28a 32.9 13.4 52.8 10.1 304.6 24.6 6.0 -4.6 -42.9 2.8 -13.0 14.2 20.2 0.0 5.7 contaminated­(4) 41 26.8 15.1 88.8 11.3 320.2 73.8 1.8 -6.0 -40.6 3.3 64.4 15.2 20.8 0.0 2.4 42 29.1 16.8 95.9 11.6 330.5 74.7 1.8 -5.5 -42.5 4.0 -42.2 -8.2 5.8 130.5 2.4 contaminated­(1) 32 30.2 15.2 89.9 11.5 324.4 74.2 1.9 -5.0 -42.9 3.0 -42.2 16.4 21.4 98.2 7.8 contaminated­(1,­4) 30 30.1 15.1 89.8 11.4 324.3 73.8 2.0 -5.7 -44.0 4.9 -5.2 16.1 20.1 269.5 7.4 contaminated­(1,­4) 31a 28.2 17.9 54.0 10.7 268.4 18.5 9.3 -5.4 -43.3 4.7 -5.2 16.4 21.4 225.0 2.4 contaminated­(1) 40 31.2 15.2 97.9 12.4 326.8 75.2 1.8 -5.3 -40.7 2.9 -13.0 16.8 8.0 17.7 5.7 contaminated­(1,­4) 31 44.4 18.7 31.8 10.2 288.9 20.7 21.7 -5.9 -42.9 3.1 150.0 -8.4 7.2 363.8 1.1 contaminated­(1) 44 44.1 18.6 31.9 10.1 289.5 18.9 20.9 -6.1 -46.5 3.0 188.0 -6.2 9.2 300.6 1.1 contaminated­(1) data­sources:­­major­ion,­stable­isotopes­and­insitu­test­data­(taufiq­et.­al.,­2017);­fe2+,­mn2+­and­nitrate­isotopes­(this­study).­ 2.2­rck­area sampling­no­ (dx) 7­major­ions 2­stable­isotopes insitu­test nitrate isotopes elevated­contaminants note 2.3­dhyk­area sampling­no­ (dx) 7­major­ions 2­stable­isotopes insitu­test nitrate isotopes elevated­contaminants note a)­cmhi­area total­ mixing ratio mg/l mp mg/l mp mg/l mp mg/l mp mg/l mp mg/l mp mg/l mp (0/00) mp (0/00) mp m 10 60.2 -0.04 23.2 -2.62 33.5 0.71 8.7 0.81 280.9 0.96 21.2 0.41 13.8 0.13 -6.2 -0.03 -46.8 -0.69 0.69 1 23.8 -2.52 10.7 0.59 16.9 1.00 7.8 1.13 184.7 1.82 4.0 1.06 8.6 0.07 -5.5 0.78 -44.2 0.86 0.37 9 59.9 -0.06 22.9 -2.54 32.6 0.72 7.5 1.24 275.2 1.01 20.8 0.42 12.7 0.12 -5.4 0.84 -38.3 4.41 0.69 2 28.0 -2.23 13.0 0.01 24.0 0.87 9.3 0.58 219.2 1.51 9.8 0.84 14.5 0.14 -6.2 0.01 -46.6 -0.56 0.37 5a 28.8 -2.18 12.8 0.05 23.8 0.88 9.3 0.57 217.4 1.53 8.8 0.88 14.5 0.14 -6.2 0.01 -45.6 0.00 0.39 3 27.9 -2.24 13.9 -0.22 23.9 0.87 9.2 0.63 217.9 1.53 9.8 0.84 15.2 0.14 -5.6 0.61 -44.8 0.49 0.37 5 68.1 0.49 26.7 -3.51 86.3 -0.22 14.9 -1.44 295.7 0.83 104.6 -2.75 54.0 0.59 -5.9 0.33 -45.5 0.11 0.30 8 59.9 -0.06 23.1 -2.59 32.5 0.72 7.4 1.26 279.5 0.98 20.9 0.42 13.4 0.12 -5.5 0.78 -44.2 0.86 0.69 6c 43.9 -1.15 18.9 -1.51 30.9 0.75 9.9 0.36 288.4 0.90 21.7 0.39 21.9 0.22 -5.7 0.53 -44.7 0.58 0.49 6 57.0 -0.26 24.1 -2.84 63.1 0.19 11.5 -0.20 206.7 1.63 45.2 -0.50 25.2 0.26 -4.7 1.60 -39.9 3.45 0.48 4 29.0 -2.17 13.2 -0.05 24.9 0.86 9.5 0.53 219.4 1.51 10.0 0.83 15.5 0.15 -6.1 0.05 -46.5 -0.52 0.38 4a 55.8 -0.34 23.8 -2.77 62.5 0.20 10.9 0.01 205.4 1.64 44.2 -0.46 24.1 0.25 -6.1 0.03 -46.5 -0.53 0.47 6b 45.2 -1.06 19.3 -1.60 32.6 0.72 10.5 0.14 290.5 0.88 21.9 0.38 22.4 0.23 -5.6 0.62 -44.6 0.60 0.50 6a 44.9 -1.08 19.2 -1.59 31.9 0.73 10.2 0.25 289.8 0.88 20.7 0.43 21.9 0.22 -5.6 0.59 -44.6 0.60 0.50 7c 45.2 -1.06 18.8 -1.49 32.6 0.72 10.5 0.14 290.5 0.88 21.9 0.38 22.4 0.23 -6.1 0.03 -46.3 -0.41 0.50 7 60.8 0.00 21.0 -2.04 73.6 0.00 11.2 -0.11 386.9 0.01 31.8 0.01 98.1 1.09 -5.9 0.26 -40.7 2.96 0.58 7b 60.1 -0.05 24.0 -2.82 33.7 0.70 9.9 0.36 285.8 0.92 21.9 0.38 13.8 0.13 -6.0 0.24 -40.8 2.92 0.68 7a 60.6 -0.02 20.8 -2.00 72.9 0.01 11.1 -0.07 385.1 0.03 30.4 0.06 97.9 1.09 -5.9 0.28 -40.8 2.92 0.59 47 25.1 -2.43 11.1 0.48 31.6 0.74 8.9 0.72 253.5 1.21 4.0 1.06 4.0 0.02 -6.5 -0.38 -45.5 0.11 0.33 46 24.8 -2.45 11.1 0.49 31.2 0.75 8.9 0.73 250.8 1.23 3.9 1.06 5.9 0.04 -6.0 0.17 -45.5 0.07 0.32 45 60.8 0.00 13.0 0.00 73.7 0.00 10.9 0.00 388.5 0.00 32.0 0.00 90.8 1.01 -6.2 0.01 -45.6 0.00 0.57 12 37.9 -1.56 19.7 -1.72 22.0 0.91 10.5 0.15 305.2 0.74 7.8 0.92 9.1 0.07 -6.0 0.14 -46.7 -0.63 0.49 12d 39.0 -1.48 18.7 -1.45 23.1 0.89 11.8 -0.33 280.7 0.96 8.6 0.89 9.3 0.08 -4.6 1.72 -38.3 4.39 0.50 12f 38.9 -1.49 19.9 -1.77 22.9 0.89 12.0 -0.40 299.9 0.79 8.1 0.91 9.2 0.07 -5.4 0.85 -42.5 1.87 0.50 1 37.2 -1.61 15.7 -0.70 25.0 0.85 8.9 0.73 267.8 1.08 2.0 1.14 4.6 0.02 -5.4 0.85 -42.5 1.87 0.51 15 79.3 1.26 34.6 -5.53 188.3 -2.01 18.6 -2.80 583.3 -1.74 141.3 -4.14 1.6 -0.01 -5.5 0.78 -44.9 0.45 0.10 15a 23.8 -2.52 8.9 1.05 78.7 -0.09 9.1 0.66 302.8 0.77 43.8 -0.45 2.7 0.00 -6.8 -0.74 -44.0 1.01 0.01 34 23.3 -2.55 8.6 1.12 75.5 -0.03 9.1 0.65 300.7 0.79 42.6 -0.40 2.6 0.00 -6.0 0.22 -42.6 1.81 0.00 39b 24.2 -2.49 9.6 0.87 78.5 -0.08 8.8 0.76 302.7 0.77 43.4 -0.43 2.5 0.00 -6.5 -0.42 -42.2 2.04 0.00 sampling­ no ca2+ mg2+ na+ k+ clso4 δ18o δ2hhco3 appendix 2. calculation results of total mixing ratio. appendix 1. continuation. g eo lo gi a c ro at ic a geologia croatica 71/3184 b)­rck­area total­ mixing ratio mg/l mp mg/l mp mg/l mp mg/l mp mg/l mp mg/l mp mg/l mp (0/00) mp (0/00) mp m 23 21.5 -1.86 8.3 5.68 10.5 3.66 2.3 -1.06 157.2 4.17 2.0 -3.23 3.2 0.04 -6.2 4.44 -51.5 -9.33 0.17 22a 39.2 -0.29 9.2 5.25 13.5 3.51 5.0 -0.22 160.8 4.08 0.6 -3.43 1.1 -0.03 -6.1 4.18 -41.0 1.87 0.12 22 39.9 -0.22 7.4 6.12 6.9 3.85 3.0 -0.85 110.6 5.34 2.7 -3.14 0.5 -0.05 -6.3 4.53 -50.8 -8.49 0.10 21 39.2 -0.29 9.3 5.18 13.6 3.50 5.0 -0.22 170.4 3.84 0.7 -3.41 1.2 -0.02 -6.3 4.55 -51.1 -8.81 0.12 33a 36.1 -0.56 15.5 2.14 48.9 1.64 6.3 0.18 275.9 1.19 44.2 2.45 8.1 0.19 -5.8 3.34 -48.4 -5.97 0.25 25 36.3 -0.54 14.9 2.44 48.2 1.68 6.5 0.23 280.1 1.09 44.1 2.43 8.7 0.21 -6.0 3.80 -48.9 -6.50 0.27 20 33.2 -0.82 25.0 -2.53 55.6 1.29 13.6 2.44 375.4 -1.31 42.6 2.23 0.8 -0.04 -5.4 2.36 -45.8 -3.20 0.03 24 25.2 -1.52 14.1 2.86 16.8 3.33 7.1 0.43 233.1 2.27 1.3 -3.33 6.4 0.14 -6.1 4.01 -48.8 -6.39 0.25 24b 25.2 -1.53 14.1 2.83 16.1 3.37 7.1 0.43 230.2 2.34 1.2 -3.34 6.3 0.13 -5.4 2.36 -45.8 -3.20 0.25 19c 38.0 -0.40 18.1 0.87 50.8 1.55 7.8 0.63 298.3 0.63 60.7 4.67 0.6 -0.04 -5.5 2.63 -47.0 -4.48 0.02 18a 46.5 0.36 19.2 0.32 110.5 -1.59 9.1 1.05 375.4 -1.31 121.7 12.87 2.7 0.02 -4.5 0.00 -42.8 0.00 0.00 20a 36.1 -0.56 16.3 1.74 49.8 1.60 6.5 0.23 278.0 1.14 44.9 2.55 8.3 0.19 -5.8 3.29 -48.4 -5.97 0.25 19 27.1 -1.36 11.5 4.10 63.6 0.87 9.3 1.11 321.6 0.04 23.5 -0.35 0.3 -0.05 -6.0 3.72 -41.7 1.12 0.03 33 36.2 -0.55 15.7 2.04 47.4 1.72 6.2 0.15 270.5 1.33 40.3 1.92 8.3 0.20 -5.8 3.25 -48.4 -5.98 0.26 27 42.43 0.00 19.85 0.00 80.24 0.00 5.72 0.00 323.41 0.00 26.03 0.00 2.00 0.00 -4.47 0.00 -42.77 0.00 0.10 18 47.3 0.43 19.4 0.23 111.5 -1.65 9.2 1.07 379.0 -1.40 123.8 13.16 2.8 0.02 -5.1 1.50 -45.4 -2.84 0.00 19b 36.3 -0.55 20.5 -0.32 57.1 1.22 19.8 4.36 612.6 -7.26 94.4 9.21 1.6 -0.01 -6.1 4.18 -41.0 1.87 0.00 c)­dhyk­area total­ mixing ratio mg/l mp mg/l mp mg/l mp mg/l mp mg/l mp mg/l mp mg/l mp (0/00) mp (0/00) mp m 11 27.5 -0.75 13.2 -5.97 18.2 1.13 8.4 2.90 126.7 2.59 40.5 0.50 14.0 0.25 -6.1 -0.47 -46.6 2.97 0.31 12 37.9 -0.02 19.7 13.79 22.0 1.07 10.5 0.81 305.2 0.25 7.8 0.97 9.1 0.15 -6.0 -0.33 -46.7 3.00 0.23 12a 38.8 0.04 19.9 14.36 22.3 1.07 11.9 -0.61 305.5 0.25 8.0 0.97 9.1 0.15 -4.6 1.97 -38.3 -1.20 0.23 12d 39.0 0.06 18.7 10.67 23.1 1.06 11.8 -0.51 280.7 0.57 8.6 0.96 9.3 0.16 -4.6 1.97 -38.3 -1.20 0.24 12f 38.9 0.05 19.9 14.39 22.9 1.06 12.0 -0.70 299.9 0.32 8.1 0.97 9.2 0.15 -5.4 0.66 -42.5 0.91 0.23 17 24.4 -0.97 9.6 -16.73 79.5 0.28 9.2 2.11 304.9 0.25 43.8 0.45 2.7 0.02 -5.5 0.45 -49.0 4.14 0.04 13 79.1 2.88 34.5 58.48 187.1 -1.21 18.5 -7.22 580.1 -3.36 140.5 -0.97 1.5 -0.01 -5.8 0.05 -44.7 2.01 0.10 29a 16.2 -1.55 7.4 -23.39 162.7 -0.87 22.6 -11.45 395.7 -0.94 40.5 0.50 6.4 0.10 -5.6 0.37 -43.8 1.54 0.05 29 16.2 -1.55 7.5 -23.33 162.6 -0.87 22.6 -11.41 395.0 -0.93 40.2 0.50 6.2 0.09 -5.6 0.36 -43.8 1.55 0.04 30a 30.6 -0.54 11.6 -10.64 35.3 0.89 7.0 4.32 295.9 0.37 2.0 1.06 4.8 0.06 -5.7 0.12 -44.0 1.64 0.14 43 38.2 0.00 15.2 0.00 99.8 0.00 11.3 0.00 324.3 0.00 74.4 0.00 1.8 0.00 -5.8 0.01 -40.7 0.00 0.00 28 33.2 -0.35 13.5 -4.97 53.1 0.65 10.3 1.02 308.5 0.21 27.0 0.69 6.4 0.10 -5.5 0.45 -42.9 1.09 0.14 28a 32.9 -0.37 13.4 -5.30 52.8 0.65 10.1 1.21 304.6 0.26 24.6 0.73 6.0 0.09 -4.6 2.00 -42.9 1.09 0.14 41 26.8 -0.80 15.1 -0.15 88.8 0.15 11.3 0.00 320.2 0.05 73.8 0.01 1.8 0.00 -6.0 -0.25 -40.6 -0.08 0.01 42 29.1 -0.64 16.8 5.00 95.9 0.05 11.6 -0.30 330.5 -0.08 74.7 0.00 1.8 0.00 -5.5 0.45 -42.5 0.91 0.01 32 30.2 -0.56 15.2 0.00 89.9 0.14 11.5 -0.16 324.4 0.00 74.2 0.00 1.9 0.00 -5.0 1.25 -42.9 1.09 0.00 30 30.1 -0.57 15.1 -0.15 89.8 0.14 11.4 -0.10 324.3 0.00 73.8 0.01 2.0 0.00 -5.7 0.10 -44.0 1.64 0.00 31a 28.2 -0.71 17.9 8.27 54.0 0.63 10.7 0.63 268.4 0.73 18.5 0.82 9.3 0.16 -5.4 0.66 -43.3 1.32 0.20 40 31.2 -0.49 15.2 0.00 97.9 0.03 12.4 -1.12 326.8 -0.03 75.2 -0.01 1.8 0.00 -5.3 0.77 -40.7 0.00 0.01 31 44.4 0.44 18.7 10.79 31.8 0.94 10.2 1.10 288.9 0.46 20.7 0.79 21.7 0.42 -5.9 -0.19 -42.9 1.09 0.46 44 44.1 0.42 18.6 10.45 31.9 0.94 10.1 1.21 289.5 0.46 18.9 0.81 20.9 0.40 -6.1 -0.57 -46.5 2.92 0.44 *) sampling no 11 13 were displayed in figure 3a) sampling­ no ca2+ mg2+ na+ k+ hco3 hco3 clso4 δ18o δ2h clso4 δ18o δ2h sampling­ no*) ca2+ mg2+ na+ k+ δ18ono3 δ15nno3 δ18ono3 δ15nno3 δ18ono3 δ15nno3 mg/l mp (0/00) (0/00) mg/l mp (0/00) (0/00) mg/l mp (0/00) (0/00) 10 1.31 0.29 4.1 20.7 16.5 c 23 3.2 0.79 4.3 6.4 12.9 c 11 2.00 0.14 3.0 18.5 13.4 c 1 1.59 3.8 38.0 28.7 d 22a 2.0 5.3 34.6 40.8 d 12 2.80 0.24 3.1 8.9 18.0 c 9 1.44 2.1 20.7 16.5 d 22 4.0 1.01 5.6 5.4 12.2 c 12a 2.99 3.1 2 1.05 0.22 5.2 21 2.1 5.3 3.6 8.2 b 12d 2.95 2.0 5a 3.00 0.74 2.5 15.6 18.4 c 33a 0.4 0.08 3.7 19.7 15.2 c 12f 2.99 2.3 33.7 38.3 b 3 1.06 2.1 25 0.5 5.5 3.8 5.7 b 17 2.58 0.21 2.0 20.1 17.8 c 5 1.89 0.45 4.3 15.4 18.0 c 20 2.0 0.50 4.0 5.2 11.4 c 13 3.80 0.36 2.9 8 3.97 2.1 38.0 28.7 d 24 0.5 3.2 4.7 8.7 b 29a 1.33 0.06 2.0 19.4 21.3 c 6c 1.20 2.3 24b 0.2 0.02 4.0 5.2 11.4 c 29 1.13 5.0 6 3.16 0.78 2.1 13.6 19.8 c 19c 0.3 0.06 2.2 18.6 14.6 c 30a 0.86 0.00 3.0 20.1 13.4 c 4 1.07 0.23 3.4 21.2 16.5 c 18a 0.2 0.01 4.4 19.8 16.2 c 43 6.59 0.70 3.9 19.4 21.7 c 4a 1.07 0.23 3.0 21.4 16.1 c 20a 0.6 0.13 3.2 6.8 10.4 c 28 6.59 3.5 6b 1.21 5.8 19 0.3 0.04 3.3 18.6 14.6 c 28a 5.70 0.59 2.8 14.2 20.2 c 6a 0.17 1.9 33 0.1 3.7 15.8 5.1 b 41 2.39 0.19 3.3 15.2 20.8 c 7c 5.34 2.7 -4.8 -2.7 a 27 0.3 0.04 7.0 18.6 12.5 c 42 2.39 4.0 -8.2 5.8 b 7 4.07 3.0 20.0 13.0 b 18 0.2 0.03 5.6 10.4 16.5 c 32 7.83 0.85 3.0 16.4 21.4 c 7b 3.63 2.7 11.9 16.5 a 19b 1.6 0.38 2.5 23.2 16.7 c 30 7.44 0.81 4.9 16.1 20.1 c 7a 3.63 6.3 20.7 18.0 a 31a 2.39 0.19 4.7 16.4 21.4 c 47 0.35 2.8 6.6 8.9 b 40 5.65 2.9 16.8 8.0 b 46 0.20 3.2 20.1 12.6 b 31 1.10 3.1 -8.4 7.2 b 45 1.71 0.40 2.8 21.2 19.1 c 44 1.05 3.0 -6.2 9.2 b 12 2.8 0.69 3.1 8.9 18.0 c *) sampling no 11 13 were displayed in figure 3a) 12d 3.0 2.0 12f 3.0 2.3 33.7 38.3 d 1 3.0 4.3 15 0.2 3.5 -1.5 6.0 b 15a 2.6 2.4 34 0.4 0.05 2.3 18.9 12.4 c 39b 2.5 3.2 8.5 25.8 a)­cmhi­area b)­rck­area c)­dhyk­area sampling­ no­(dx) nitrate composito nal­range nitrate isotopes sampling­ no­(dx) nitrate do nitrate isotopes no3 compositonal­ range no3 composito nal­range no3 do nitrate isotopes sampling­ no­(dx) nitrate do appendix 3. calculation results of mixing ratio of nitrate concentration and their nitrate isotopes. appendix 2. continuation.  upper turonian–santonian slope limestones of the islands of premuda, ist and silba (adriatic coast, croatia)  alan moro and vlasta ćosović department of geology and paleontology, faculty of science, university of zagreb, horvatovac 102a, 10000 zagreb, croatia; (amoro@geol.pmf.hr, vcosovic@geol.pmf.hr) doi: 10.4154/gc.2013.01 geologia croatica 66/1 1–13 3 figs. 4 pls. zagreb 2013 geologia croaticageologia croatica ab stra ct upper turonian–santonian limestones at three island locations (ist, silba and premuda) in the southwestern part of the adriatic carbonate platform, record slope deposition based on their sedimentological and palaeontological characteristics. these upper cretaceous successions consist of three vertically superimposed lithotypes: (1) pelagic mudstonespackstones, (2) laminated pelagic wackestones-packstones, and (3) bioclastic floatstones-rudstones to packstonesgrainstones with fossils of shallow marine organisms. according to the proximity of the shallow water carbonate platform interior the depositional setting of the slope deposits could be identified as relatively more proximal or distal. the proximal part is characterized by non laminated pelagic limestones with resedimented bioclastic limestones, while the more distal parts have both laminated and nonlaminated pelagic limestones with rare resedimented bioclastic limestones. the resedimented bioclastic limestones represent slope apron deposits. locally, at premuda island, the slope apron includes blocks of laminated pelagic limestones. the depositional environments of the ist and premuda profiles could be interpreted as of more distal origin, while those of the silba profile represents a more proximal part of the slope. keywords: pelagic, resedimented, limestones, slope apron, slump, rudists, planktonic foraminifera, upper turonian-santonian, adriatic carbonate platform water sedimentation was re-established. interestingly, on the southwestern part of the adriatic carbonate platform deep water sedimentation lasted from the early turonian to the end of cretaceous (kapović & bauer, 1970; fuček et al., 1991). generally, deep water carbonates are divided into two major sedimentary facies differing in depositional criteria and diagenetic development: (1) pelagic carbonates composed of fine grained sediments with pelagic organisms and (2) resedimented allochthonous carbonates with constituents exported from the platform and slope settings farther into the basins (flügel, 2004). this division is used in this paper as the basis for interpretation of the depositional environments of the investigated localities. 1. introduction the adriatic carbonate platform (adcp) was one of the largest mesozoic carbonate platforms of the perimediterranean region (herak, 1986, 1990; tari 2002; vlahović et al., 2005). today the upper cretaceous limestones that originated on this platform crop out along the eastern adriatic coast in a more or less continuous nw-se trending belt. a shallow water regime persisted throughout the late cretaceous, with just two episodes of drowning, first during the early turonian and secondly during the santonian (gušić & je laska, 1990; moro et al., 2002; vlahović et al., 2005; korbar, 2009). following both drowning events shallow geologia croatica 66/1geologia croatica 2 the aims of this paper are (a) to determine the age attribution based on planktonic foraminifera and (b) to describe the depositional environments of the platform-to-basin transition. particular emphasis is placed on the description of the lithofacies characteristics and possible palaeoenvironmental conditions involved in their formation. 2. geological setting the upper cretaceous sedimentary rocks from three sections on the islands of ist, silba and premuda were sampled and studied (fig. 1). the sections belong to the external dinarides (herak, 1986; 1990) or dinaridic sw unit or high karst (korbar, 2009) region, comprising the geotectonic unit of folded and faulted upper cretaceous and palaeogene strata (mamužić, 1970; mamužić et al., 1970; ma mužić & sokač, 1973; moro & jelaska, 1994; ćosović et al., 1994; márton & moro, 2009; márton et al., 2010). the transition from the cretaceous to the palaeogene was marked by emersion, and occasionally with bauxite deposits (kovačević galović et al., 2012). bedding dips from 20 to 87 degrees (fig. 1). the investigated profiles comprise tectonically uninterrupted successions of upper cretaceous strata. 3. methods the structural characteristics of the rocks, bed thicknesses, potential cyclicity, and macrofossils were studied in the field. samples from the massive limestones were collected for thin -section analysis to investigate the microfacies (including textures and skeletal components) and biostratigraphic characteristics. visual percentage charts were used to estimate the relative abundance of grains (baccelle & bosellini, 1965; in flügel, 2004). the taxonomic study of planktonic foraminifera is based on randomly oriented sec tions through the test with observable morphological characteristics such as test shape and peripheral thickenings or keels (premoli silva & sliter, 2002; sari, 2009). the taxonomic framework used to identify species is based on the practical manual of cretaceous planktonic foraminifera (premoli silva & sliter, 2002; premoli sil va figure 1: simplified geological map (after mamužić, 1970 and mamužić et al., 1970) showing the location of the investigated profiles. a– silba profile, b–premuda profile, c–ist profile. arrows indicate the younging direction of the successions. 1– cenomanian –turonian 2– turonian-senonian, 3– senonian, 4– paleogene. alan moro & vlasta ćosović: upper turonian–santonian slope limestones of the islands of premuda, ist and silba (adriatic coast, croatia) geologia croatica 3 & verga, 2004) and publications by sari (2006, 2009). the biostratigraphic scheme is according to premoli sil va & sliter (2002). 4. lithofacies and biostratigraphy of the investigated profiles lithofacies analysis is based on the study of rock specimens in thin-sections, supplemented by features observed in the field such as bedding, sedimentary structures and macrofossil content. three different lithofacies types have been distinguish ed: (a) laminated pelagic limestones (lf 1), (b) pelagic limestones (lf 2) and (c) bioclastic limestones (lf 3). texturally, both pelagic limestones are mud-supported mudstonespackstones, and bioclastic limestones are mudand grain-supported floatstones-rudstones and packstones-grainstones. 4.1. the silba profile the maximum total thickness of the studied profile at silba is 47 m (fig. 2). bed thickness ranges from 40–120 cm. the succession consists of lf 2 and lf 3 lithofacies; lf 2 comprises pelagic wackestones-packstones with bed thickness from 40–120 cm and lf 3 consists of bioclastic grainstonesrudstones-floatstones with beds 40–60 cm thick. in vertical succession, lf 2 beds are present throughout the section. lf figure 2: schematic vertical succession of the investigated profiles. thickness of the beds is not to scale. 1a– pelagic limestones (lf 2), b– laminated pelagic limestones (lf 1), c– intercalations of bioclastic limestones within laminated pelagic limestones (lf 3), 2– bioclastic limestones with bioclasts (a– fragments, b– rudist shells) and lithoclasts (c) (lf 3), 3– slump forms, 4 – slope apron facies with blocks of laminated pelagic limestones, 5–structural type: wackestone, packstone, grainstone, floatstone, rudstone. x, o and ◊ in black – cf. probable identification. geologia croatica 66/1geologia croatica 4 3 appears as bioclastic grainstones-rudstones in the lower part, and floatstone intercalations and lenses with pelagic limestones in the upper part of the section. macrofossils are whole shells and fragments of radiolitid and hippuritid rudist bivalves (pl. 1, fig. 6). the lf 2 ranges from pure pelagic packstones with densely packed pelagic particles (pl. 2, fig. 1) (estimated percentage of pelagic particles is up to 50%), predominantly made of calcispheres with rare planktonic foraminifera (1– 2.5%), to wackestones-packstones with pelagic particles (20–25%) and fragments of bioclasts of shallow marine origin (5–10 %) and lithoclasts (3–7.5%). rarely, these limestones are slightly laminated, where rare shallow water bioclasts are horizontally orientated. bioclastic rudstones con sist of poorly sorted coarse fragments of rudists, which make up to 40–50% of a thin section (pl. 3, fig. 7). grainstones are dominated by shallow water macrofossil fragments (40–50%) and lithoclasts (7.5–15%) (pl. 3, fig. 5). in mud supported packstones-floatstones the estimated percentage range of pelagic particles is 7.5–20%, shallow water bioclasts 20–25% and lithoclasts 7.5–10% (pl. 3, figs. 4, 6 & 12). some lithoclasts contain rare small miliolid foraminifera and pelagic particles (pl. 2, fig. 3). the microfossil assemblages are composed of planktonic foraminifera: marginotruncana marginata (reuss), m. renzi (gandolfi), m. cf. paraconcavata porthault, m. schneegansi (sigal), archaeoglobigerina sp., dica rine­ lla sp., globigerinoides sp., hedbergella sp., heterohelix sp. (pl. 4, figs. 34–47) and calcispheres. the most common shallow water fossil is the cyanobacterium decastronema kotori (radoičić) (golubić et al., 2006) (pl. 3. fig. 13);less common are the calcareous alga thaumatoporella parvove­ siculifera (raineri), milolids and shells of hippuritids and radiolitids. the assemblage of planktonic foraminifera listed above is dominated by species having double-keels and a low trochospiral test, which correspond to the h. helvetica, m. si­ gali-d. primitiva, d. concavata and d. asymetrica planktonic foraminiferal zones, biostratigraphically characteristic of the late turonian – santonian interval (premoli silva & sliter, 2002). 4.2. ist profile the ist profile is a 74 metre-thick succession (fig. 2). all three (lf 1, lf2 and lf 3) lithofacies types are present. lf 1 occurs in thin to thick beds (5–60 cm) as laminated pelagic wackestones-packstones, lf2 as pelagic wackestones in beds of variable thickness (20–180 cm), and lf 3 as bioclastic grainstones-packstones-rudstones-floatstones with 15 to 60 cm thick intercalations. in vertical succession lf 1 appears as individual beds associated with one or more beds of lf2, ranging in thickness from 0.7 to 16. 4 m. lf 3 appears in lf 1 and lf 2. lf 3 appears within lf2 randomly as intercalations contains fragments of, and whole radiolitid and hippuritid shells (pl. 1, fig. 10). the intercalations have sharp bases and tops, or undulating, uneven, rough contacts (pl. 1, fig 10). patches of lf 2 pelagic limestone are rarely present within lf 3 floatstones-rudstones, (pl. 1, fig. 2). bioclastic limestones appear as 1–2 cm thick intercalations within lf 1 lithofacies. thin-sections of lf 1 reveal laminated pelagic particles making up to 3–15% of total sediment, while the frequency of planktonic foraminifera is estimated to be 1–2.5% (pl. 2, fig. 7). they may also contain intercalated bioclastic packstones–grainstones with shallow water macrofossil fragments and lithoclasts making up 20–50% of a thin–section (pl. 2, figs. 2 & 11). lf 2 is characterized by pelagic skeletal grains (3–12.5%), with the frequency of planktonic fora minifera varying from 1–3%. within lf 2 lithofacies, the estimated frequency of shallow-water fossil fragments is 2.5– 5%, and lithoclasts 1–3% (pl. 2, figs. 5 & 13). intercalations of lf3 consist of pelagic (1–7.5%), and shallowwater derived bioclasts with a frequency of 20–50% (pl. 3, figs 1 & 2). lithoclasts (7.5–20%) containing shallow water foraminifera are also present (pl. 3, figs. 2 & 11). these resedimented bioclastic and lithoclastic grains of lf 3 (pl. 2, figs 2 & 4; pl. 3. figs. 1 & 2), with partial to complete grain support, show evidence of slightly normal grading (pl. 2, figs. 4, 9 & 11) when they appear as intercalations within lf 1. the tops and bottoms of intercalations within lf1 are flat, locally with flute marks at the base (pl. 2, fig. 9). the upper part of the profile consists of slump deposits (0.80 m thick and 4.80 m long), deformed limestones belonging to the lf2 lithofacies (pl. 1, fig. 8). the fossil assemblage comprises the following foraminiferal species and organisms: marginotruncana cf. coronata (bolli), m. pseudo­ linneiana pessagno, m. cf. renzi (gandolfi), m. sinu­ osa porthault, m. cf. paraconcavata porthault, m. schnee gansi (sigal), globigerinoides sp., hedbergella sp., heterohelix sp. (pl. 4, figs. 1–15) and calcispheres. scando­ nea samnitica (de castro) (pl. 3, fig. 11), decastronema kotori (radoičić), thaumatoporella parvovesiculifera (rai neri), shell fragments of hippuritids and radiolitids, and rare occurrences of red algae (pl. 3, fig 10) are observed within resedimented shallow-water particles and lithoclasts. the planktonic foraminifera determined in the ist succession indicate the h. helvetica, m. sigali-d. primitiva, d. concavata and d. asymetrica planktonic foraminiferal zones, which suggest the late turonian – santonian interval (premoli silva & sliter, 2002). 4.3. premuda profile the premuda succession (figs. 1 & 2, pl. 1, fig. 7) is 149 m thick and consists of three lithofacies: lf 1 laminated pelagic wackestone-packstones (2 to 120 cm thick beds), lf 2 pelagic wackestones-packstones (as 20 to 120 cm thick beds), and lf 3 bioclastic packstones-grainstones-floatstones-rudstones. lf 2 and lf 1lithofacies are cyclically organized, with one or several beds of lithofacies lf 2 separated by an individual bed of lf 1 lithofacies in 0.26 to 4.4 m thick packages (pl. 1, fig. 7). the lf 3 lithofacies when present (rarely) is intercalated within lf 1 as packstones-grainstones, while within lf2 beds it appears as rare intercalations at the base, alan moro & vlasta ćosović: upper turonian–santonian slope limestones of the islands of premuda, ist and silba (adriatic coast, croatia) geologia croatica 5 or as lenses within the bed, with fragments and whole shells of radiolitids. the thickness of lf 3 intercalations within host lf 2 beds ranges between 10–20 cm. some beds of lf 2 have a wavy to lenticular or ellipsoidal appearance (pl. 1, figs. 9 & 11), and occur within both lf1 and lf 2 limestones. thin-sections of lf 1 contain planktonic foraminifera and calcispheres with an estimated frequency of 5–25% and 1–2.5% for planktonic foraminifera (pl. 2, fig. 6). lithoclasts and shallow water bioclasts are rare. interbedded within the lf1 type, bioclastic packstones-grainstones consist of shallow water bioclasts (25–50%) and lithoclasts (7.5%). within the lf 2 lithofacies, the estimated frequency of pelagic skeletal grains ranges from 1 to 2.5% (pl. 2, fig 12), while shallow-water macrofossil fragments and occasional lithoclasts are rare (pl. 2, fig 8). packstone variants of this lithofacies with calcispheres (20–40%) are rare and appear in the lower part of the succession. floatstones-rudstones-packstonesgrainstones of lf 3 contain lithoclasts (10–30%) and shallow water bioclasts with an estimated frequency of 20–25% (pl. 3, fig. 3). pelagic bioclasts are present in mud supported floatstones-packstones with an estimated percentage of 2.5– 7.5%. the 20 m thick sequence in the middle part of the profile represents dissected blocks of strata (pl. 1, fig. 5) of pelagic laminated limestones (pl. 1, fig. 3). these blocks occur within bioclastic floatstones-rudstones (pl. 1, figs. 1 & 4; pl. 2, fig. 10), packstones-grainstones and pelagic mudstoneswackestones, and show no evidence of bedding. bioclastic floatstones-rudstones and packstones-grainstones contain pel lets, peloids, and shallow water bioclasts (12.5–40%), while pelagic bioclasts occur sporadically (pl. 3, fig. 8 & 9). pelagic mudstones-wackestones contain pelagic microfossils (3–7.5%). the upper part of the profile is composed of 3.50 m thick slump sediments within pelagic limestones of lf 2 (fig. 2). the microfossil assemblage comprises the following plank tonic foraminiferal species: marginotruncana margi­ nata (reuss), m. cf. coronata (bolli), m. pseudolinneana pessagno, m. cf. sinuosa porthault, m. paraconca­ vata porthault, m. tarfayaensis (lehmann), globi­ gerinoides sp., hedbergella sp. and heterohelix sp. (pl. 4, figs. 16–33). calcispheres are also present. within the premuda succession, the determined macrofossils include vaccinites cornuvaccinum (bronn) (pl. 1, fig. 1) and shells of hippuritids and radiolitids. remnants of green algae thaumatoporella parvovesiculifera (raineri) also occur. the biostratigraphic age of the premuda succession is late turonian – santonian based on the range of low-trochospiral marginotruncanids which comprise the h. helvet­ ica, m. sigali-d. primitiva, d. concavata and d. asymetrica planktonic foraminiferal zones (premoli silva & sliter, 2002). also, the chronostratigraphic age interval for v. cornuvaccinum is uppermost turonian to middle coniacian (steuber, 1999; steuber & schlüter, 2012), which is consistent with microfossil dating, though implying the older part of the interval for this species. 5. lithofacies analysis the limestones described above constitute different lateral parts of slope deposits. the shallowest, proximal, upper part of the slope is represented by the silba succession, and the more distal, deeper, lower part of the slope is represented by the ist and premuda successions. an ideal vertical sequence consists of all the aforementioned limestones, starting from pelagic limestones in the proximal part of the slope to pelagic and laminated pelagic limestones in the more distal parts. the laminated pelagic limestones are developed from the premuda profile, diminishing towards the silba profile, where this lithofacies becomes completely absent (figs. 2 & 3) implying the more proximal position of the latter. a similar pattern of appearance is shown by the shallow water bioclastic limestones, which are considered to be debris to grain-flow deposits resedimented on a slope apron (tucker & wright, 1990, flügel, 2004). in the more distal part (premuda succession) they are present as intercalations and lenses within pelagic limestones, and almost com pletely absent from the laminated pelagic limestones. towards the proximal part of the slope (ist succession) (pl. 2, figs. 4 & 9; pl. 3, figs1, 2, 10 & 11) they appear commonly as intercalations within pelagic limestones and locally within laminated pelagic limestones. in the most proximal part (silba succession) bioclastic limestones form lenses and intercalations in pelagic limestones or individual beds (pl. 3, figs. 4, 5, 6 & 7). a resedimented sequence, present only in the premuda succession, consists of shallow-water and pelagic deposits that are part of the slope apron with large blocks of laminated pelagic limestone transported in a disaggregated matrix of shallower slope facies (fig. 3; pl. 1, figs. 3 & 5). such resedimented limestones could be considered as megabreccias, presumably the result of seismic shocks and gravity collapses (spence & tucker, 1997; flügel, 2004). here they are present in the distal part of the slope (fig. 3) and most probably resulted from sediment overloading in the upper part of the slope. within the shallow water bioclastic limestones, the major constituents are two types of grains: bioclasts of shallow marine origin and lithoclasts. the bioclasts are mainly whole shells and angular fragments of rudists, benthic miliolid foraminifera as well as the green algae thaumatoporella and cyanobacterium decastronema. the lithoclasts are dark fragments of mud-supported limestones originating from the shallow water part of the platform or upper part of the slope. this type of lithoclast indicates the absence of typical platform margin-derived material (e.g. ooids, reef fragments). most probably, as in the western dolomites (brandner et al., 1991), they were eroded from various parts of shallowwater platform environments where the mud-supported limestones originated, from peritidal (with shallowing upward cycles) to relatively deeper subtidal settings (gušić & jelaska, 1990; moro et al., 2002; vlahović et al., 2005). at the nearby shallow water part of the platform (moro & jelaska, 1994) the difference in relative depth of shallowwater subtidal and intertidal sediments could be small. therefore it seems that the appearance of lithoclasts is the result geologia croatica 66/1geologia croatica 6 of more or less laterally pronounced shallow water submarine topographic relief, which, as a result of resedimentation processes, produced lithoclasts as well as bioclasts. another possible explanation is that the appearance of lithoclasts implies higher values of slope angle (kenter, 1990) together with a relatively prolonged lack of shallow-water subtidal accommodation space. lenticular and wavy structures within the pelagic and laminated pelagic limestones of the premuda succession presumably represent the distal part of the slope apron where the major constituents are mud and pelagic particles. these bed-forms probably resulted from lateral differentiation in the mechanical strength of the apron deposits, leading to distal creep and fringing forms. another possible explanation is that the bed-forms are slumps originating from the slide and creep of semi-consolidated, internally undeformed sediments, probably due to sediment overloading (flügel, 2004). pronounced bedding-planes along these structures make the latter possibility more likely (pl. 1, figs. 9 and 11). slope strata that include debris to grain-flow deposits and slumps could be formed on a wide range of slope angles (kenter, 1990; flügel, 2004). grain supported fabrics with minor or no matrix, build up on the upper parts of the slopes with higher angles (up to 40 degrees), and those with mud matrix form the lower parts of the slope with low slope angles (up to 15 degrees). mixtures of grain to mud support ed fabrics appear in all three successions, most commonly in the proximal parts of the slope (silba profile), while towards the distal part (premuda profile) there is a decrease in their frequency of occurrence. this kind of muddy and granular fabric mixture is typical of slopes with angles between 5–25 degrees (flügel, 2004), implying that the investigated lime stones were deposited on a relatively low angle slope. also, the majority of ancient slope apron resedimented carbonates are developed along rather gentle (less than 4 degrees), shallow platform to basin slopes (tucker & wright, 1990). nevertheless, the slope apron sediments with blocks of laminated pelagic limestones in the premuda figure 3: a block diagram showing the reconstructed depositional environments of the study area. 1– bioclastic limestones of the slope apron, 2– pelagic limestones with slump features, 3– shallow-water subtidal deposits, 4– slope apron with blocks of laminated pelagic limestones, 5– laminated pelagic limestones, 6– intertidal laminites. not to scale. plate 1 1 – vaccinites cornuvaccinum in slope apron sediments, premuda profile; 2 – shallow water bioclastic floatstone-rudstone with patches of pelagic limestone (arrows), ist profile; 3 – block of laminated pelagic wackestone-packstone within slope apron (arrows), premuda profile; 4 – shallow water bioclastic floatstone with radiolitid shells within slope apron, premuda profile; 5 – slope apron, premuda profile; 6 – lenses of shallow water floatstone with rudists shells and shallow water bioclasts within pelagic wackestone-packstone, silba profile; 7 – vertical succession of pelagic mudstones-wackestones and laminated pelagic wackestones-packstones, premuda profile; 8 – slump within vertically dipping beds, ist profile; 9 – frontal part of slump with sliding and creeping pelagic wackestone, premuda profile; 10 – intercalation of the shallow water bioclastic floatstone-rudstone with uneven, sharp contact with pelagic wackestones (arrows), ist profile; 11 – lens of sliding and creeping pelagic wackestone within frontal part of slump (arrows), premuda profile. alan moro & vlasta ćosović: upper turonian–santonian slope limestones of the islands of premuda, ist and silba (adriatic coast, croatia) geologia croatica 7 geologia croatica 66/1geologia croatica 8 succession (fig. 3) are predominantly mud-supported limestones, implying very low-angle, low-relief carbonate slopes with deposits consisting of broad sheets of debris (tucker & wright, 1990). 6. shallow platform to basin transect although the detailed lateral transition of the shallow platform to basin transect in the investigated area is obscured by the insular restriction of the outcrops (fig. 1), it is possible to reconstruct a general model for the distribution of the shallow platform-to-basin depositional environments during the late cretaceous for this part of the adriatic carbonate platform. this model includes vertical variation of depositional environments on the adriatic carbonate platform during flooding of the platform and re-establishment of the shallowwater sedimentation (moro et al., 2002; vlahović et al., 2005). there are several possibilities for the origin of the enormous amount of carbonate mud, most probably including disintegration or compaction of soft peloids and faecal pellets, together with bioerosion of the hard parts of shallow water organisms (fürsich et al., 2003). this amount of carbonate mud, together with oscillations of accommodation space provided for their deposition, resulted in the mosaic of slope deposits visible in the vertical appearance of pelagic and resedimented allochthonous carbonates. the vertical alternation of laminated and non-laminated pelagic limestones within the distal part of the slope is probably a reflection of the shallowing upward cycles within the shallow water part of the platform. the pelagic limestones with a lower frequency of pelagic particles in comparison with the laminated pelagic limestones, were probably deposited while intertidal conditions with low accommodation space prevailed at the shallow-water part of the platform, thus more mud was delivered to the deeper water environments. in contrast, the laminated pelagic limestones would have been deposited when more accommodating subtidal conditions prevailed at the shallow part of the platform, with the lamination reflecting oscillations in the amount of platform mud that settled from suspension. the late cretaceous adriatic carbonate platform was vast (dercourt et al., 1993) and is generally represented by low energy limestones with biostromes of elevator rudists that lived as mud-supported dwellers within different parts of the subtidal environments (skelton & gili, 1991; ross & skelton, 1993; gili et al., 1995; moro & ćosović, 2000; 2002; simone et al., 2003). during the flooding as well as renewed shallowing following deeper marine deposition, there is no evidence in the vertical succession of the adriatic carbonate platform deposits of movement of a possible barrier, with or without rudists, towards the proximal or distal part of the platform (moro et al., 2002, 2008; vlahović et al., 2005). presumably the shallow water deposits were protected by the gradual deepening of the carbonate platform (gušić & jelaska, 1990; moro & ćosović, 2002; moro et al., 2008; korbar et al., 2010), which ended with foundered platform deposits (moro et al., 2002; vlahović et al., 2005). the same pattern of absence of a barrier could be presumed for this part of the gently inclined late cretaceous adriatic carbonate platform as has been postulated for the slope sediments of the catalan basin (calvet & tucker, 1988). 7. conclusion according to the sedimentological and palaeontological analyses of the upper cretaceous limestones of the premuda, silba and ist islands, it is possible to conclude the following: 1) on the basis of the planktonic foraminifera, as well as rare benthic micro and macrofossils, the studied sediments are assigned to the upper turonian-santonian. 2) a platform to basin depositional transect of slope deposits is reconstructed, which can be divided into proximal and distal parts. proximal slope sediments comprise nonlaminated pelagic limestones with resedimented bioclastic limestones, while more distal slope sediments are characterized by both laminated and non-laminated pelagic limestones with rare resedimented bioclastic limestones. 3) resedimented bioclastic limestones appear as slope apron deposits. locally, on premuda island, the slope apron includes blocks of distal laminated pelagic limestones. slumps within the pelagic limestones are present on the premuda and ist islands. 4) the platform margin was characterized by a gradually deepening subtidal environment, lacking any kind of barrier. acknowledgement the authors would like to thank robert w. scott, bilal sari and guest editor p.w. skelton for providing valuplate 2 1 – pelagic packstone, silba profile; 2 – laminated pelagic limestone with intercalation of shallow water packstone-grainstone with shallow water bioclasts and lithoclasts, ist profile; 3 – pelagic wackestone with lithoclast of pelagic packstone, silba profile; 4 – lower (left) and upper (right) part of the intercalation of the shallow water material within laminated pelagic limestone, ist profile; 5 – pelagic wackestone-packstone with shallow water bioclasts and lithoclasts, ist profile; 6 and 7 – pelagic laminated limestones, premuda (6) and ist (7) profile; 8 – lithoclast with thaumatoporella within pelagic wackestone, premuda profile, 9 – resedimented shallow water packstone-grainstone with flute marks (arrows) within laminated pelagic wackestonepackstone, ist profile; 10 – floatstone with fragments of rudists (arrows) within slope apron, premuda profile; 11 – laminated pelagic wackestone-packstone with intrusion of shallow water packstone, ist profile; 12 and 13 – pelagic wackestones, premuda (12) and ist (13) profile. alan moro & vlasta ćosović: upper turonian–santonian slope limestones of the islands of premuda, ist and silba (adriatic coast, croatia) geologia croatica 9 geologia croatica 66/1geologia croatica 10 able advices, suggestions and exact notations which improved the manuscript. the authors also thank r. košćal for computer preparation of figures and s. deroko for boat transportation. this work was supported by a grant from the ministry of science, education and sport of the republic of croatia, projects 0019-1101152-1167 and 0019-11011521169. references baccelle, l. & bosellini, a. (1965): diagrammi per la stima visiva della composizione precentuale nelle rocce sedimentarie.– annali della universitá di ferrara, sezione ix, science geologiche e paleontologiche, 1, 59–62. brandner, r., flügel, e. & senowbari-daryan, b. (1991): microfacies of carbonate slope boulders: indicator of the source area (middle triassic: mahlknecht cliff, western dolomites).– facies, 25, 279–296. calvet, f. & tucker, m. (1988): outer ramp cycles in the upper muschelkalk of the catalan basin, northern spain.– sedimentary geology, 57, 185–198. doi: 10.1016/0037-0738(88)90026-7 ćosović, v., balončić, d., koić, m., marjanac, t., moro, a., gušić, i. & jelaska, v. (1994): palaeontological evidence of paleogene transgression on adriatic carbonate platform.– géologie méditerranéenne, 21/3–4, 49–53. dercourt j., ricou l.e. & vrielynck b. (1993): atlas tethys palaeoenvironmental maps.– gauthier villars, paris. flügel, e. (2004): microfacies of carbonate rocks – analysis, interpretation and application. – springer, berlin. 976 p. fuček, l., jelaska, v., gušić, i., prtoljan, b. & oštrić, n. (1991): padinski sedimenti uvale brbišnica na dugom otoku (turonian slope deposits in the brbišnica cove, dugi otok island, croat ia).– geološki vjesnik, 44, 55–67. fürsich, f.t., wilmsen, m., seyed-emami, k., schairer, g. & majidifard, m.r. (2003): platform-basin transect of a middle to late jurassic large-scale carbonate platform system (shotori mountiains, tabas area, east-central iran).– facies, 48, 171– 198. doi: 10.1007/bf02667538 gili, e., masse, j-p & skelton, p.w. (1995): rudists as gregarious sediment dwellers, not reef-builders, on cretaceous carbonate platforms.– palaeogeography, palaeoclimatology, palaeoecology, 118, 245–267. doi: 10.1016/0031-0182(95)00006-x golubić, s., radoičić, r. & seong-joo, l. (2006): decastrone­ ma kotori gen. nov., comb. nov.: a mat-forming cyanobacterium on cretaceous carbonate platforms and its modern counterparts.– carnets de géologie/notebooks on geology, cg2006_a02, 1–17. gušić, i. & jelaska, v. (1990): stratigrafija gornjokrednih naslaga otoka brača u okviru geodinamske evolucije jadranske karbonatne platforme [upper cretaceous stratigraphy of the island of brač within the geodynamic evolution of the adriatic carbonate platform – in croatian].– djela jugoslavenske akademije znanosti i umjetnosti, 69, jazu-igi, zagreb, 160 p. herak, m. (1986): a new concept of geotectonics of the dinarides (no va koncepcija geotektonike dinarida).– acta geologica, zagreb, 16, 1–42. herak, m. (1990): dinaridi-mobilistički osvrt na genezu i strukturu (dinarides-mobilistic view of the genesis and structure.– acta geologica, zagreb, 21, 35–117. kapović, b. & bauer, v. (1970): sedimentološke, biofacijalne i ambijentalne karakteristike gornjokrednih naslaga otoka premuda i du gog otoka [sedimentary, biofacies and environmental charac­ teristics of the upper cretaceous sediments of the premuda island and dugi otok – in croatian].– nafta, 22, 12, 561–572. kenter, j.a.m. (1990): carbonate platform flanks: slope angle and sediment fabric.–sedimentology, 37, 777–794. doi: 10.1111/j.1365 -3091.1990.tb01825.x korbar, t. (2009): orogenic evolution of the external dinarides in the ne adriatic region: a model constrained by tectonostratigraphy of upper cretaceous to paleogene carbonates.– earth-science reviews, 96/4, 296–312. doi: 10.1016/j.earscirev.2009.07.004 korbar, t.; cvetko tešović, b.; radovanović, i., krizmanić, k., steuber, t. & skelton, p.w. (2010): campanian pseudosabinia from the pučišća formation on the island of hvar (adriatic sea, croatia).– turkish journal of earth sciences, 19/6, 721–731. doi: 10.3906/yer-0901-9 kovačević galović e., ilijanić, n., peh, m., miko, s. & hasan o. (2012): geochemical discrimination of early palaeogene bauxites in croatia.– geol. croat., 65/1, 53–65. mamužić, p. (1970): osnovna geološka karta sfrj: 100 000, list molat l 33–138 [basic geological map sfry, sheet molat – in croatian].– savezni geološki zavod beograd. mamužić, p., sokač, a. & velić, i. (1970): osnovna geološka karta sfrj 1:100 000, list silba l 33–126 [basic geological map of sfry, sheet silba – in croatian].– savezni geološki zavod beograd. mamužić, p. & sokač, b. (1973): tumač za listove silba i molat l 33–126, l 33 138 [basic geological map of sfry 1:100 000, ge­ ology for sheets silba and molat – in croa tian].– savezni geološki zavod beograd, 45 p. márton, e. & moro, a. (2009): new palaeomagnetic results from imbricated adria: ist island and related areas.– geol. croat., 62/2, 107–114. doi: 10.4154/gc.2009.09 márton, e., ćosović, v., bucković, d. & moro, a. (2010): the tectonic development of the northern adriatic region constrained by jurassic and cretaceous paleomagnetic results.– tectonophysics, 490/1–2, 93–102. doi: 10.1016/j.tecto.2010.04.032 moro, a. & jelaska, v. (1994): upper cretaceous peritidal deposits of olib and ist islands (adriatic sea, croatia).– geol. croat., 47/1, 53–65. moro, a. & ćosović, v. (2000): the rudists of southern istria – an example of environmentally induced succession within santonian limestones.– rivista italiana di paleontologia e stratigrafia, 106/1, 59–71. moro, a. & ćosović, v. (2002): rudists and larger benthic fora minifera as relative indicators of water depth – an example from the istrian (upper cretaceous and eocene) part of the adriatic carbonplate 3 1 – grainstone with shallow water bioclasts and lithoclasts, ist profile; 2 – floatstone with shallow water bioclasts and lithoclasts, ist profile; 3 – floatstone, premuda profile; 4 – packstone with shallow water bioclasts and lithoclasts, silba profile; 5 – grainstone, silba profile; 6 – rudist floatstone, silba profile; 7 – rudist rudstone, silba profile; 8 and 9 – slope apron. wackestone-packstone with miliolids (8) and packstone-grainstone with shallow water bioclasts and lithoclasts (9), premuda profile; 10 – fragment of red algae within floatstone-rudstone, ist profile; 11 – floatstone matrix with pelagic bioclasts and lithoclast with scandonea samnitica, ist profile; 12 – packstone with calcispheres, shallow water bioclasts, silba profile; 13 – pelagic packstone with decastronema kotori (arrow), silba profile. alan moro & vlasta ćosović: upper turonian–santonian slope limestones of the islands of premuda, ist and silba (adriatic coast, croatia) geologia croatica 11 geologia croatica 66/1geologia croatica 12 ate platform.– memorie della società geologica italiana, 57, 203– 208. moro, a., skelton, p.w. & ćosović, v. (2002): palaeoenvironmental setting of rudists in the upper cretaceous (turonian-maastrichtian) adriatic carbonate platform (croatia), based on sequence stratigraphy.– cretaceous research, 23, 489–508. doi: 10.1006/cres. 2002.1017 moro, a., mezga, a., ćosović, v., tunis, g. & tarlao, a. (2008): rudists and dinosaur footprints – mutual relationship within mud-supported upper cenomanian peritidal limestones of istria, croatia.– bollettino della societa geologica italiana, 127/2, 423– 428. premoli silva, i. & sliter, w.v. (2002): practical manual of cretaceous planktonic foraminifera. international school on planktonic foraminifera 10 course: cretaceous (ed: premoli silva, i. & rettori, r.).– dipartimento di scienze della terra, university of perugia (italy), 462 p. premoli silva, i. & verga, d. (2004): practical manual of cretaceous planktonic foraminifera, 3rd course: cretaceous.– universities of perugia and milan, tipografia pontefelcino, perugia (italy), 283 p. ross, d.j. & skelton, p.w. (1993): rudist formations of the cretaceous: a palaeoecological, sedimentological and stratigraphical review.– sedimentology review, 1, 73–91. sari, b. (2006): upper cretaceous planktonic foraminiferal biostratigraphy of the bey daglari autochthon in the korkuteli area, western taurides, turkey.– journal of foraminiferal research, 36/3, 241– 261. doi: 10.2113/gsjfr.36.3.241 sari, b. (2009): planktonic foraminiferal biostratigraphy of the coniacian-maastrichtian sequences of the bey daglari autochthon, western taurides, turkey: thin-section zonation.– cretaceous research, 30, 1103–1132. doi: 10.1016/j.cretres.2009.03.007 simone, l., carannante, g., ruberti, d., sirna, m., sirna, g., laviano, a. & tropeano, m. (2003): development of rudist lithosomes in the coniacian-lower campanian carbonate shelves of central-southern italy: high energy vs low-energy settings – palaeogeography, palaeoclimatology, palaeoecology, 200, 5–29. doi: 10.1016/s0031-0182(03)00442-5 skelton, p.w. & gili, e. (1991): paleoecological classification of rudist morphotypes.– in: sladic-trifunovic, m. (ed.): first international conference on rudists, proccedings, serbian geological society, belgrade, 71–86. spence, g.h. & tucker, m.e. (1997): genesis of limestone megabreccias and their significance in carbonate sequence stratigraphic mo dels: a review.– sedimentary geology, 112, 163–193. doi: 10.1016/ s0037-0738(97)00036-5 steuber, t. (1999): cretaceous rudists of beotia, central greece.– special papers in paleontology, 61, 229 p. steuber, t. & schüter, m. (2012): strontium-isotope stratigraphy of upper cretaceous rudist bivalves: biozones, evolutionary patterns and sea-level change calibrated to numerical ages.– earthscience reviews, 114, 42–60. doi: 10.1016/j.earscirev.2012.04.004 tari, v. (2002): evolution of the northern and western dinarides: a tectonostratigraphic approach.– egs stephan mueller publication series, european geophysical society, 1, 1–21. tucker, m. & wright, v.p. (1990): carbonate sedimentology.– black well scientific publications, oxford, 482 p. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeography, palaeoclimatology, palaeoecology, 220, 333–360. doi: 10.1016/j.palaeo.2005.01.001 manuscript received july 12, 2012 revised manuscript accepted december 12, 2012 available online february 28, 2013 plate 4 planktonic foraminifera ist profile: 1. marginotruncana cf. pseudolinneiana, 2. hedbergella sp., 3. globigerinoides sp., 4. marginotruncana cf. renzi, 5. m. cf. coronata, 6. hedbergella sp., 7. marginotruncana pseudolinneiana, 8. m. schneegansi, 9. m. cf. pseudolinneiana, 10. m. pseudolinneiana, 11. heterohelix sp., 12. marginotruncana cf. paraconcavata, 13. m. sinuosa, 14. m. pseudolinneiana, 15. m. pseudolinneiana premuda profile: 16. heterohelix sp., 17. marginotruncana cf. tarfayaensis, 18. m. marginata, 19. marginotruncana sp., 20. m. paraconcavata, 21. m. pseudolinneiana, 22. m. cf. sinuosa, 23. hedbergella sp., 24. marginotruncana pseudolinneiana, 25. marginotruncana sp., 26. m. paraconcavata, 27. m. tarfayaensis, 28. marginotruncana sp., 29. m. pseudolinneiana, 30. marginotruncana sp., 31. marginotruncana sp., 32. m. cf. coronata, 33. m. pseudolinneiana silba profile: 34. marginotruncana cf. schneegansi, 35. m. schneegansi, 36. m. marginata, 37. m. schneegansi, 38. m. cf. paraconcavata, 39. marginotruncana sp., 40–41. archaeoglobigerina sp., 42. marginotruncana renzi, 43. dicarinella sp., 44–46. marginotruncana sp., 47. m. cf. marginata alan moro & vlasta ćosović: upper turonian–santonian slope limestones of the islands of premuda, ist and silba (adriatic coast, croatia) geologia croatica 13 geologia croatica 66/1geologia croatica 14 2016 | 69/2 | 269–279 | 5 figs. | 3 tabs. | www.geologia-croatica journal of the croatian geological survey and the croatian geological society geochemistry of lower palaeogene bauxites – a unique signature for the tectonostratigraphic evolution of part of the croatian karst zoran peh and erli kovačević galović croatian geological survey, sachsova 2, p.o. box 268, hr-10000 zagreb, croatia; (corresponding author: zpeh@hgi-cgs.hr) doi: 10.4154/gc.2016.24 abstract the origin and emplacement of lower paleogene bauxites discussed here relies on recent perceptions concerning the development of the collision-induced diachronous discontinuity surfaces in certain parts of the adriatic-dinaric carbonate platform (adcp), and in the istrian peninsula in particular. this process, related to forebulge uplift during the initial stages of the orogeny, is amply recorded in the geochemical signature of related istrian lower paleogene bauxites (ilpb) as was shown in previous investigations. as their self-evident extension, due attention is paid here to the effects of a flexural bulge in another part of the platform with its own suite of lower paleogene bauxite deposits (lpb), notably in its dinaridic unit. explication of the typical patterns of bauxite formation is grounded in the development of discriminant function models based on the compositional data (coda) analysis of geochemical data. this method provides the solid ground for separation of the various a priori defined bauxite groups deposited in the different subaerially exposed platform palaeoenvironments. in the final analysis, the discriminant model characteristic for the westernmost compartment of the adriatic sw unit (istrian karst) is cross-compared with the analogous model of the entire adcp taken from earlier investigation but reconsidered within the coda framework. it is done with the purpose of assessing the geochemical correspondence between the two event-markers (ilpb and lpb) and clarifying the nature of the pertinent tectonostratigraphic constraints. the computer models show that the forebulge unconformity is not a widespread phenomenon, being distinctly recognized only in the istrian part of the adcp. the most recent investigations of bauxites in croatia had addressed the root causes of geochemical variations observed in the bauxite deposits of lower palaeogene age (lpb) from the croatian karst (kovačević galović et al., 2012) (fig. 1), focusing especially on the istrian peninsula due to its specific geodynamic evolution through cretaceous to palaeogene times (peh & kovačević galović, 2014). these studies attempted to explain regular variations in bauxite geochemistry both within regional (adcp) and subregional (istrian peninsula) contexts highlighting changes of depositional and diagenetic characteristics during subaerial exposure of the platform. although istrian lower palaeogene bauxites (ilpb) accommodate the overall geochemical trend (marked primarily by the southeastward increase in chromium content), their stratigraphic position at the regional k–pg unconformity occurring in the adriatic part of the platform (adriatic domain, sensu korbar, 2009) must be treated with due caution because of the implicit possibility of a unique geochemical signature resulting from tectonostratigraphic constraints. essentially, the implied peculiarity of the ilpb revolves around the major hiatus between the cretaceous and palaeogene carbonate successions, which unlike the more south-eastern portions of the adcp, lasted seemingly longer in istria (e.g. velić et al., 1995; matičec et al., 1996; tišljar et al., 1998; vlahović et al., 2005; otoničar, 2007, 2008; korbar, 2009; cvetko tešović et al., 2011). as a result, the ilpb are underlain by carbonate rocks characterized by a wide age interval (from albian to santonian-coniacian) suggesting the predominance of tectonic over eustatic controls due to differential 1. introduction in spite of extensive bauxite research and mining activities in croatia which provided abundant mineralogical and chemical archives, bauxite genesis, particularly in relation to the palaeokarst and its tectonostratigraphic constraints, has been underrated. most certainly, this unfavourable situation can be ascribed to earlier prevailing perspectives on bauxites predominantly as an aluminum ore, with all research efforts concentrated on the assessment of conditions of their detection, exploitation and refinement. occasionally, they were treated in the broader context of palaeoclimaterelated geochemical and mineralogical processes (e.g. šinkovec, 1973, šinkovec & sakač, 1982, 1991; sakač & šinkovec, 1991) and of local tectonics (blašković et al., 1989). however, their tectonically induced origin was considered more seriously only after the models of orogenic evolution of the adriatic (adriatic/dinaric) carbonate platform (adcp) had been constructed with special reference to the external dinarides of the ne adriatic region, e.g. by vlahović et al., 2005; korbar, 2009; brlek et al., 2014. this approach, drawing also from „recognition of forebulge related unconformities associated with early stages of foreland basin development” (crampton & allen, 1995), stressed the significance of a number of stratigraphic gaps occurring in the mesozoic-tertiary successions of the croatian dinarides. considered from this perspective, the complex investigation of bauxites as „tectonic and climatic event markers at regional unconformities” (d’argenio & mindszenty, 1995) stimulated a search for a new lithostratigraphic scheme setting the background for regional correlation studies over the entire platform. article history: manuscript received december 01, 2015 revised manuscript accepted may 11, 2016 available online june 28, 2016 keywords: bauxite geochemistry, compositional data, discriminant function model, forebulge unconformity, adriatic-dinaric carbonate platform, croatia g eo lo gi a c ro at ic a geologia croatica 69/2270 erosion caused by uplift (mindszenty et al., 1995), and also a prolonged period of terrestrial conditions necessary for the accumulation and diagenesis of the protobauxitic material. presumably, the geochemical signal of the ilpb has responded to the coeval tectonostratigraphic constraints in a somewhat different way with respect to other lpb groups marked by different stratigraphic positions within the adcp (dinaric domain, sensu korbar, 2009; kovačević galović et al., 2012). this premise infers a tacit antagonism between the ilpb and the other lpb groups, concerning their geotectonic setting – adriatic vs. dinaric domains of the adcp – whereby the latter are associated with an unconformity formed during the supposedly shorter late cretaceous (santonian-early campanian) to palaeogene (earlymiddle eocene) hiatus and, as a result, are underlain by carbonate bedrock of approximately the same age. the idea underlying this study was to assess the analogy between the temporal sequences of the four ilpb groups (adriatic) (peh & kovačević galović, 2014) and the spatial emplacements of other, presumably single-sequence „non-istrian” lpb groups (dinaric) (kovačević galović et al., 2012), based on their corresponding geochemical signatures. it is conceivable to elucidate the behaviour of the pb geochemical signal in different tectonostratigraphic settings, particularly with respect to development of a forebulge. this line of reasoning, in which time series (ilpb overlying a discontinuity surface at various stages of development) are substituted for spatially sampled data from a sufficiently large spatial domain (lpb from istria to dalmatia), is commonly termed „ergodic” (implying space-for-time substitution). in pursuit of an ergodic solution, the integrated analysis of spatial and temporal domains generally requires comparison of appropriate models. for this purpose, a multivariate statistical assessment of a primary geochemical pattern distinguishing between the four groups of ilpb, (a priori separated according to bauxites overlying carbonate formations of different cretaceous ages), was carried out using multiple discriminant analysis (mda) as the most suitable mathematical technique. mda is employed as a method of data reduction and organization providing an efficient means of geochemical partitioning between several bauxite groups defined by an independent criterion, in this case the stratigraphic formations, or lithostratigraphic units. the developed discriminant function model (dfm) is designed to account for the geochemical changes in time reflected in the ilpb due to the existent (presumably long-lived) subaerial exposure of the istrian part of the adriatic platform. the other model describing the variety of forms (bauxites) „frozen” in a distinct timeframe related to the regional (apparently shorter) hiatus over a large proportion of a platform (dinaric), is taken from earlier research (kovačević galović et al., 2012) and redefined in the spirit of the coda analysis for comparison purposes. the aforementioned spatial-temporal correspondence (if present) is expected to be substantiated by analysis and reflected in the matching geochemical signal from both models. since the whole rock geochemical data analyzed here are of a compositional nature (represented in wt% and mg/kg), providing information about relative magnitudes (as proportions of a whole), their statistical treatment is necessarily focused on the log-ratio approach introduced by aitchison (1982; 1986) and disseminated by contemporary proponents of compositional data analysis (e.g., tolosana-delgado et al., 2005; aitchison & egozcue; 2005; buccianti et al., 2006; reimann et al., 2012; buccianti, 2013). 2. geological setting the croatian dinaric karst (ne adriatic region) is an area of thick carbonate successions deposited from the middle permian to the eocene on carbonate platforms of different ages, type and geotectonic settings. some unresolved issues concerning its orogenic evolution in the later stages of development, particularly the relationship between the end-member palaeogeographic and geodynamic models is still subject to differing interpretations (vlahović et al., 2005, and references therein; korbar, 2009, and references therein). these models postulate the existence of a single (e.g. vlahović et al., 2005) as opposed to two carbonate platforms (e.g. korbar, 2009), usually with adriatic-dinaric designation (adcp), developed as a result of fragmentation of the adriatic microplate (adria) during the upper triassic and the lower jurassic, and subsequent events at its plate boundaries (e.g. vlahović et al., 2005; schmid et al., 2008; korbar, 2009; sisciani & calamita, 2009; ustaszewski et al., 2010 and references therein; márton, et al., 2010; šumanovac, 2010; márton, et al., 2011; nocquet, 2012; hinsbergen et al., 2014). one of the themes highly relevant to the genesis of bauxites is associated with different tectonostratigraphic constraints characterizing the two contrasting platform domains, namely dinaric and adriatic, both with their pertinent tectonostratigraphic units, proposed in spite of the still uncertain nw extension of the budva basin and time of opening of the ne adriatic trough (korbar, 2009) (fig. 2). the first refers to the recent external dinarides, a highly deformed fold-and-thrust belt of alpine origins formed by the collision of adria with the austroalpine and tisia domains. the other is the adriatic foreland, a more stable part of adria characterized by normal faulting and gentle compressional late-orogenic deformations, which are tectonic features typical for istria (matičec, 1994; matičec et al., 1996). although the dynamic interplay of synsedimentary tectonic activity and eustatic changes had continually modified the adcp figure 1. topographic sketch map showing areas included in the two bauxiteresearch campaigns relevant for this study: 1 – geochemical investigation of lower palaeogene bauxites (lpb) from the croatian part of the adriatic-dinaric carbonate platform (adcp) (kovačević galović et al., 2012); 2 – geochemical investigation of lower palaeogene bauxites from the istrian peninsula (ilpb) (peh & kovačević galović, 2014). g eologia c roatica zoran peh and erli kovačević galović: geochemistry of lower palaeogene bauxites – a unique signature for the tectonostratigraphic evolution ... 271 until the final uplift of the karst dinarides reaching its maximum extent during the oligocene-miocene period, from the perspective of bauxite formation only the period between the end of the lower cretaceous and the beginning of the palaeogene is of interest for the scope of this investigation. this period is highlighted by a major discrepancy in the nature of a regional unconformity developed on the carbonate platform, marked by recognition of the strong forebulge effect in the adriatic domain, istria in particular, a feature only hinted at previously in the southeastern part of dinaric high karst. as one of the five tectonostratigraphic units in the stratigraphic scheme of the entire adcp, the istrian peninsula is recognized as the adriatic sw unit (aswu) or istrian karst (korbar, 2009) (fig. 3), sometimes called stable istria (e.g. márton et al., 2003; márton et al., 2010). most of it is distinguished by a prolonged emersion phase at the cretaceous–palaeogene (k–pg) boundary which caused a major hiatus between the two carbonate platform depositional systems – the cretaceous passive margin shallow-marine carbonate sequence of the adriatic carbonate platform and the upper cretaceous and/or palaeogene shallow-marine sequences of the synorogenic carbonate platform, resulting from the specific evolution of the adriatic foreland basin complex (aswu). a major regional subaerial unconformity resulting from flexural deformation (uplifting forebulge) in front of the approaching dinaric orogen is locally denoted by prono-pronounced palaeokarstic features (durn et al., 2003; otoničar, 2007; korbar, 2009; brlek et al., 2013). these clues firmly support the idea that a large part of present day istria probably formed land until the onset of the palaeogene transgression (matičec et al., 1996). however, no direct relationship with bauxite formation can be established in the area since the oldest bauxite-hosting rocks are represented by limestones of albian age while the scattered outliers of the eocene carbonate rocks overlie still older lower cretaceous formations (of valangian to barremian age), indicating erosional vacuity devoid of bauxites (peh & kovačević galović, 2014). the complete stratigraphy of the adcp carbonates from the istrian karst was described at length with reference to the typical lower and upper cretaceous successions in vlahović (1999) as well as in gušić & jelaska (1990) and cvetko tešović et al. (2001), respectively. albian to campanian lithostratigraphic units relevant to this investigation include the following in ascending chronostratigraphic succession: 1) pula formation (pu – albian), 2) rušnjak formation (ru – cenomanian), 3) sveti duh formation (sd – upper cenomanian-lower turonian) and 4) gornji humac formation (gh – upper turonian-upper santonian/campanian) (matičec et al., 2013). the latter three formations have been derived after the similar succession reported from the island of brač (gušić & jelaska, 1990; steuber et al., 2005), with modifications. in contrast to the istrian peninsula, the south-eastward portion of the dinaric high karst (dinaridic sw unit, or dswu, sensu korbar, 2009) is characterized by a santonian (early campanian) to late palaeocene hiatus encompassing the coniacian to santonian interval (earlier determined as turonian to „lower senonian”), narrowing considerably the approximate age interval of the associated bauxites. the absence of an obvious tectonically induced bulging effect (diachronous uplift), ruled out differential erosion that would have occurred during the subaerial exposure of the platform interior, introducing an entirely different kind of unconformity in this area. accordingly, the k–pg boundary over the entire dswu is marked by the underlying cretaceous bedrocks having similar ages, such that the upper cretaceous strata underlying the bauxites generally shows bioand lithofacies characteristics of the gornji humac (gh) formation figure 2. simplified tectonic map of the adriatic-dinaric carbonate platform (adcp), modified from korbar (2009): 1) aswu (istrian karst); 2) aneu (dalmatian karst); 3) dswu (high karst); 4) dneu (inner karst); 5) thrust front of the external dinarides; 6) thrusts of adriatic and dinaridic units; 7) other major faults; 8) investigated groups of lower palaeogene bauxites (lpb) from different quarters of the adcp (after kovačević galović et al., 2012): ist – istria, nai – northadriatic islands, nda – north dalmatia, cda – central dalmatia. figure 3. simplified geological map of the istrian peninsula (compiled from the geological map of the republic of croatia, 1:300,000, croatian geological survey, 2009) showing locations of the sampled istrian lower palaeogene bauxites (ilpb): 1) upper jurassic formations; 2) lower cretaceous formations (including pu); 3) upper cretaceous formations (ru–gh); 4) palaeocene–middle eocene formations; 5) middle eocene–upper eocene formations (flysch); 6) thrust faults; 7) investigated istrian lower palaeogene bauxites (ilpb) grouped in accordance to underlying cretaceous formations (after peh & kovačević galović, 2014). g eo lo gi a c ro at ic a geologia croatica 69/2272 (korbar, 2009; korbar et al., 2012). this is strong evidence in support of a major discrepancy between the bauxite depositional environments concerning the two tectonostratigraphic units (aswu vs. dswu) in the croatian karst. although both are related to plate-interior settings (mindszenty et al., 1995; d’argeno & mindszenty, 1995), they differ according to the longevity of the hiatus and consequences of the arching effect which is typical only for istria. 3. materials and methods 3.1. sampling, sample preparation and geochemical analysis sampling was carried out on several occasions so that 50 lpb bauxite samples were collected from various sites all over the adcp (including 21 early samples from istria) (kovačević galović et al., 2012) and 45 new istrian samples added in a later campaign to complete the sampling scheme for the separate investigation of the ilpb (peh & kovačević galović, 2014) (fig. 1). samples from all locations were collected in a random fashion following the idea that bauxites from a single regional unconformity (k–pg transition) should represent a bulk geochemical composition regardless of their particular horizons within the ore body (e.g. at the contact with the related palaeokarst or immediate cover), particularly in the case of small deposits (100-300 m2) or occurrences typical for lpb in croatia (fig. 4). it is tacitly accepted in this work that multivariate analysis carried out on the bulk geochemistry of a number of cases is capable of identifying the most important geochemical processes by reducing all details along the vertical profile to a few mathematical functions. bauxite samples weighing about 3 kg in total were crushed by hand, split into fractions by quartering, and finally ground in a tungsten carbide pestle mortar mill (retsch lab equipment) and sieved to 0.063 mm in preparation for the analytical work. chemical analysis was performed at the acme labs (acme analytical laboratories ltd.) in vancouver, canada, applying the lithogeochemical whole rock major and trace element analytical method. total abundances of the major oxides and a few minor elements were reported on a 0.2 g sample analyzed by icpemission spectrometry following a lithium metaborate/tetraborate fusion and dilute nitric digestion. total trace elements were analyzed by icp mass spectrometry – refractory elements went through the same decomposition as the major elements (additional 0.2 g sample) while the rest were digested in hot aqua regia and analyzed by icp ms (0.5 g sample). analytical work was subjected to the strictest quality control in the acme labs, with blanks, duplicates and standard reference materials (std so-18) included in the cq report, together with a certificate of analysis, as a measure of background noise, accuracy and precision. for the purpose of this work, the procedure for handling the data below the analytical detection limit (left-censored data) was accepted from tarvainen et al. (2005) as the substitution method of assigning one-half the detection limit value to censored data. this method is predominantly in use in geochemical and environmental studies (as per antweiler & taylor, 2008) developed from earlier works on analytical chemistry (e.g., analytical methods committee, 1987). 3.2. statistical considerations 3.2.1. compositional data and log-ratio analysis statistical analysis employed a selection of 32 elements including 10 major elements (represented as total abundances of major oxides) and 22 trace elements (cr represented as cr2o3) performing as predictor variables in mda. data from earlier research work embracing lpb from all over the adcp had to be recalculated into log ratios in order to be compatible with the recent discriminant function model (dfm) of istrian bauxites. the strategy of analysis was adjusted to the objectives of this research so that ilpb data were installed as a foundation for the reference model against which lpb data were weighed (including identical procedures described in chapter 3.1). this arrangement meant that the tables in most cases combined the results of analysis of both data sets albeit separately and lpb is discussed later in the text (denoted as a, and b). the analyzed dataset consists of 66 bauxite samples collected from ilpb deposits and occurrences, a priori separated into the four groups in accordance with rock formations (informal lithostratigraphic units from aswu) as their immediate bedrock. the four groups include the pula formation (pu), rušnjak formation (ru), sveti duh formation (sd) and gornji humac formation (gh) in upward succession. in contrast, the associated lpb database contains a total of 50 samples previously collected from different quarters of the adcp (including istria) and categorized in the four groups with a geographic designation: istria (ist), north adriatic islands (nai), north dalmatia (nda), and central dalmatia (cda) (kovačević galović et al., 2012); approximately in a nw-sw direction. the summary statistics for the whole dataset prior to data transformation and subsequent multivariate statistical procedure are displayed in table 1 (minimum, maximum, median, and geometric mean). however, this information is relevant only if one is interested in relative rather than absolute values such as, for example, in the case of comparison with other similar investigations, because the whole rock composition of bauxite samples represents the classical example of compositional data (coda) in geochemistry. although the basic principles of coda are thoroughly explained in the previous work on bauxites (peh & kovačević galović, 2014) it is deemed necessary to reiterate this issue again to some extent due to its relative novelty in the croatian scientific literature, especially among geologists. the nature of coda implies a mathematical property that all variables (compositions) in the analyzed sample must sum to a unit value (100% or 1.0). as a result, all geochemical, mineralogical, and other datasets in the geoscience world are heavily plagued by the constant-sum constraint (csc). this problem interferes with procedures of traditional statistics since individual variables figure 4. outcrop of a small-scale lower palaeogene bauxite deposit (lpb) on pag island (metajna-zubovići) g eologia c roatica zoran peh and erli kovačević galović: geochemistry of lower palaeogene bauxites – a unique signature for the tectonostratigraphic evolution ... 273 are represented only as parts of some whole (or fractions of a constant sum) and, prevented from fluctuating independently (closed data), they are involved in spurious correlations. formally, coda cannot be represented in their raw form as points in the open, euclidean space, where the scale is absolute, not relative. they refer to a restricted sample space known as simplex (simplicial complex) consisting of d parts or compositions (e.g. geochemical variables). thus a d-part composition (sd) is really a subset of d-dimensional real space (rd) (pawlowsky-glahn & egozcue, 2006) which can assume the euclidean vector space structure only after the proper transformation of its components. from an array of transformations introduced in the literature, the centered log-ratio transformation (clr) of raw (compositional) data, originally proposed by aitchison (1986) is used here. the application of the centered log-ratio is deemed essential for processing coda in the multivariate statistical methods such as mda since it preserves original distances between corresponding compositions allowing them to be handled in a straightforward way (egozcue & pawlowsky-glahn, 2006; tolosana-delgado, 2012). the singularity problem inherent to a clr-transformed covariance matrix could be circumvented if mda operates on its reduced form, which is not relying on a full rank of covariance (daunis-i-estadela et al., 2011). since clr-transformed data represent unbounded real vectors in real space, in this case mahalanobis distances (md) stay invariant regardless of which component may be removed from the analysis (barceló-vidal & pawlowsky-glahn, 1999). nonessential clr-transformed variables may be amalgamated („other”) and removed from further analysis. clr-coefficients are computed from the following expression: clr(x) = ( )  xg x1log , log ( )xg x2 , log ( )xg x3 , …., log ( )  xg xd : where x1, x2, x3,…xd represent parts (compositions), and g(x) represents the geometric mean of the parts. as the compositional nature of geochemical data is expressed either in wt %, or in mg/kg, affecting the scale, all measurements are converted into mg/kg before transformation by multiplying wt% by 104. 3.2.2. building a predictive discriminant model (dfm) multiple discrimination analysis (mda) is one of the most exploited traditional multivariate statistical techniques particularly effective in building the predictive models of a multi-group discrimination established on the array of independent, or predictor variables. this method is amply described in earlier papers with similar targets and subjects of investigations (e.g. peh & halamić, 2010; peh & kovačević galović; 2014; galović & peh, 2016) and will not be thoroughly discussed table 1. descriptive statistics of raw (compositional) geochemical data for a) ilpb, and b) lpb datasets. a) ilpb b) lpb element min med max g min med max g sio2 (%) 0.91 4.58 21.72 4.31 1.02 3.415 9.1 3.41 al2o3 (%) 33.02 48.75 57.20 47.54 34.5 50.415 58.58 49.82 fe2o3 (%) 4.13 24.58 42.21 25.02 14.76 25.955 45.96 25.62 mgo (%) 0.04 0.13 0.49 0.13 0.06 0.11 0.49 0.12 cao (%) 0.03 0.08 7.80 0.10 0.04 0.115 0.64 0.10 na2o (%) 0.005 0.01 0.33 0.01 0.005 0.01 0.33 0.01 k2o (%) 0.005 0.06 0.24 0.05 0.005 0.03 0.2 0.03 tio2 (%) 1.30 2.90 3.67 2.76 1.6 2.955 3.88 2.84 p2o5 (%) 0.005 0.06 1.84 0.05 0.00 0.053 0.113 0.05 mno (%) 0.005 0.05 0.12 0.05 0.02 0.05 0.46 0.06 cr2o3 (%) 0.047 0.07 0.252 0.08 0.053 0.085 0.208 0.10 ni (mg/kg) 52 200.00 524 186.31 88.0 224.5 1092.0 222.43 sc (mg/kg) 30 47.50 123 47.43 35.0 54.0 91.0 56.07 ba (mg/kg) 6 25.00 66 23.88 6.0 24.0 73.0 23.63 co (mg/kg) 12 33.85 81 31.87 14.2 38.2 91.9 38.29 ga (mg/kg) 25.3 49.85 66.4 48.54 33.6 53.55 65.1 52.49 nb (mg/kg) 23.8 54.95 70.9 53.22 30.7 59.4 75.4 56.47 sr (mg/kg) 27.6 96.95 992.7 96.56 27.6 74.7 220.4 74.59 th (mg/kg) 24.8 43.50 71.1 42.69 28.5 45.25 60.7 45.25 u (mg/kg) 4.6 10.60 29.4 11.05 4.6 8.7 26.9 8.58 v (mg/kg) 202 425.50 1341 444.38 286.0 539.0 1876.0 565.45 zr (mg/kg) 246.6 517.20 667.9 497.95 312.3 532.55 721.2 523.30 y (mg/kg) 31.4 64.65 111.0 61.44 31.4 69.7 255.9 77.00 la (mg/kg) 40.7 87.75 146.0 87.11 40.70 93.8 179.3 94.00 ce (mg/kg) 64.6 178.35 1096.9 172.74 64.6 193.8 645.3 203.49 mo (mg/kg) 0.9 6.65 44.8 6.43 0.9 7.55 33.0 6.95 cu (mg/kg) 14.5 95.35 247.6 87.75 21.9 82.3 250.5 87.40 pb (mg/kg) 21.4 74.15 119.7 72.40 44.2 97.6 196.6 97.80 zn (mg/kg) 10 74.00 633 78.65 12.0 90.0 422. 93.01 as (mg/kg) 0.25 51.15 269.60 45.18 1.7 36.15 154.9 28.57 cd (mg/kg) 0.05 0.85 4.40 0.79 0.1 1.2 11.0 1.19 hg (mg/kg) 0.03 0.29 2.23 0.29 0.03 0.225 1.02 0.22 note: min = minimum; med = median; max = maximum; g = geometric mean g eo lo gi a c ro at ic a geologia croatica 69/2274 here. this also relates to the process of model building – from the structural to the functional, by assigning the geological meaning to discriminant functions (labeling) – which is the stepping stone of each mda. it suffices to say that here, the scope of this study is focused on building the two predictive discriminant models with maximum classification efficiency, based on the two sets of bauxite groups defined earlier as: a) ilpb (containing pu, ru, sd and gh groups) and b) lpb (containing ist, nai, nda and cda groups); and the 32 log-ratio transformed coda chemical variables (whole rock chemical analysis). the latter set (b) includes the log ratio adjusted lpb model already defined in the earlier project (kovačević galović et al., 2012) and added to this investigation for comparison purposes and discussion on tectonostratigraphic constraints with possible ergodic implications. to this end, a discriminant analysis from the statistical software package of statistica, release 7.1 (statsoft, inc., 2006) was used in order to achieve the best separation between the groups. 4. results and discussion results of the mda are briefly recapitulated in table 2. containing: a) the multivariate test for the overall significance of discrimination and; b) the tests of residual roots (discriminant functions). the wilks’ l statistical test, employed routinely in the analysis, shows the vanishingly low probability (p<0.000) confirming that all bauxite groups have the same multivariate mean, which is compulsory in order to safely proceed with computing discriminant functions (dfs). since the number of groups in the studied cases is only four (k=4) the between-group variation is completely explained by the three discriminant functions (k–1). however, examination of table 2. reveals that only the first two discriminate functions justify closer inspection. df1 and df2 together account for more than 94% and almost 93% of the total between-group difference in ilpb and lpb models, respectively, allowing the third one to be easily disregarded. for the sake of convenience and prevention of possible confusion, the interpretation of the two models will proceed separately allowing, as it were, the lpb model to be „integrated” with the already built tectonographic scheme of the istrian karst (peh & kovačević galović, 2014). 4.1. labeling the functions the function labeling for the ilpb dataset has been presented in peh & kovačević galović, 2014, so that the pertinent discriminant model of the istrian karst will only be briefly revisited since the comparison of the two models (ilpb+lpb) is indispensable for their integration into the greater adcp scheme. it suffices to say that in the computed mathematical model of the ilpb (tab. 2a; fig. 5a-b), the first discriminant function df1 highlights the simple enrichment/depletion master relationship while df2 provides additional insight both into the process of ferralization experiencing manganese enrichment in the final stages, and into various anaerobic processes affecting organic-rich argillaceous sediments in the poorly drained protobauxitic material. for the lpb model previously constructed by classical statistical techniques all mda paraphernalia had to be recomputed in the coda spirit (tab. 2b; fig. 5c-d). 4.2. lpb model revisited – the coda approach previous investigation of lower palaeogene bauxites revealed an exceptional role for cr in their disposition over the dinaric karst (kovačević galović et al., 2012). however, from the standpoint of statistical modeling, the lpb model discussed in earlier work suffered from a variety of problems arising from the traditional raw data approach. one of the greatest shortcomings was the separate analysis of major and trace elements resulting in two different dfms, each encumbered by the problem of sub-compositional incoherence (incoherence of the correlation between the two raw components as a measure of dependence) (e.g. pawlowsky-glahn & egozcue, 2006; aitchison, 2008). here, this issue is resolved by the compositional data approach which allows working on the full set of geochemical data in terms of ratios (such as clr coefficients) always preserving sub-compositional coherence. also, one of the major fallacies related to „classical” statistical methods is exposed by the coda analysis. specifically, in some cases, including the previously established lpb model (kovačević galović et al., 2012), it may turn out that the new methodology validates what is already known through the use of traditional methods with raw compositional data. however, the straightforward answer to this dilemma is that more often than not „either the researcher was lucky using his traditional methods or at least the new methodology must be correct in that case” (aitchison, 2008). the coda dfm is strikingly similar to its classical counterpart particularly in the portion applying to the group arrangement based on the latter’s trace element dataset (kovačević galović et al., 2012). however, correspondence also exists for the major-element suite so that the new model integrates the whole set of transformed compositional data in euclidean space allowing for more coherent interpretation of geochemical data in the bauxite-forming environment. this is to say that specific performance of cr is reinstated by its complementary positioning with regard to bauxitic/clay components (primarily k2o, followed by al2o3, tio2 and others). as a strongly bipolar function, df1 clearly separates the north adriatic ist and nai groups against the dalmatian nda and cda groups (fig. 5c-d), showtable 2. multivariate test for overall significance of discrimination, and tests of residual roots for a) ilpb discriminant function model, and b) lpb discriminant function model. a) no. of variables 32 no. of samples 66 wilks’ lambda 0.015 approximate f ratio 2.972 degrees of freedom [96; 93] p-level p < 0.0000 df eigen value eigen (%) canon. r wilks’ l chi2 df plevel 1 10.339 77.23 0.955 0.015 196.6 96 0.000 2 2.289 17.10 0.834 0.173 82.5 62 0.042 3 0.759 5.67 0.657 0.568 26,6 30 0.647 b) no. of variables 32 no. of samples 50 wilks’ lambda 0.00036 approximate f ratio 6.2687 degrees of freedom [96; 45] p-level p < 0.0000 df eigen value eigen (%) canon. r wilks’ l chi2 df plevel 1 54.510 81.51 0.991 0.000 245.8 96 0.000 2 7.417 11.09 0.939 0.020 121.3 62 0.000 3 4.948 7.40 0.912 0.168 55.3 30 0.003 note: lpb data clr-transformed from kovačević galović et al., 2012. g eologia c roatica zoran peh and erli kovačević galović: geochemistry of lower palaeogene bauxites – a unique signature for the tectonostratigraphic evolution ... 275 ing the latter as a repository for the ingress of cr from some external source – most probably the dinaridic ophiolite belt with ultramafic massifs and genetically related sedimentary formations (pamić et al., 2002) in the internal dinarides. this input is so strong that, in all probability, the lpb deposited further to the nw simply reflects the sharp decline in cr content putting to the forefront other bauxite components mentioned above. with the introduction of df2 (only 11.1% of total variability) the overall picture is only embellished by separating the nai and nda groups as more enriched in aluminum and related components (al2o3, tio2, ga, nb) as well as rare earths and associated elements (ce, la, p2o5, sc, y). this leaves the ist group as generally the most kaolinitic (k2o) among the investigated bauxites (upper left quadrant of fig. 5c-d). 4.3. a geochemical signal – setting the limits of the bauxite age? as suggested before, the specific tectonostratigraphic constraints characterizing different adcp units imply the possibility of a hidden coherence underlying the unique geochemical signatures of both the ilpb and lpb in general. this particular line of correspondence can be scanned from analogous discriminant models developed for both instances. in this regard the mahalanobis distances (md) computed for the ilpb model can be compared with the rebuilt model from the earlier geochemical investigations of the lpb over the entire adcp (kovačević galović et al., 2012) as illustrated in table 3. in the former case the multivariate distances increase successively from the pu upward, putting the sd at the upper end of the sequence indicating the greatest md values, more than twice those of the youngest, gh group (tab. 3a). ru is also closer, that is, more similar by its geochemical signature, to the gh than to the sd. in the latter however, a somewhat different response is observed, in this instance with regard to the spatial rather than temporal relationships – four lpb groups distributed along the nw-se directed k–pg regional unconformity, from istria (ist) to central dalmatia (cda) (spatially „ascending”, or easting), showed a regular tendency to increase the cr-signal towards the se with a characteristic acme at the central dalmatian (cda) group, the last in the sequence (ist ® nai ® nda ® cda) (tab. 3b). hence, spatial and temporal arrows have characteristic peaks that correlate the chronological position of the bauxite-hosting sd formation in istria (relatable to the supposed cr–event) with the spatial position of the cda group of the lpb along the same discontinuity surface at the k-pg boundary. the rapport between the two models provides a rationale for comparing the controls of subaerial exposure (tectonic uplift in the plate-interior settings during collision along the distant plate margins, according to figure 5. comparison between variables and groups in the ilpb and lpb discriminant function model (clr transformed data): scatterplots of variable loadings (a,c), and individual objects (samples) (b,d) in reduced discriminant space of the first two discriminant functions (df1-df2). table 3. mahalanobis distances (md) for a) ilpb discriminant function model, and b) lpb discriminant function model. a) ilpb b) lpb group pu ru sd gh group ist nai nda cda gh up w ar d su cc es sio n à 0.00 cda n w à s e 0.00 sd 0.00 31.49 nda 0.00 83.16 ru 0.00 70.32 28.52 nai 0.00 161.64 274.32 pu 0.00 26.49 149.98 71.52 ist 0.00 40.68 202.30 309.22 à upward succession nw à se note: lpb data clr-transformed from kovačević galović et al., 2012. g eo lo gi a c ro at ic a geologia croatica 69/2276 d’argenio & mindszenty, 1995), invoking an ergodic hypothesis as a working tool. although some authors hold it inappropriate to swap spatial for temporal variability in ergodic approaches to climate-tectonics-erosion studies (balco & stone, 2005) it can, in truth, be the only way to model stochastic processes in case if no sample helps meaningfully to predict values that are very far away in time of that sample. this line of reasoning assumes that spatially sampled data can be substituted for time series (paine, 1985) which is particularly useful in contrasting the two discussed dfm. a singular, (probably the same) event (cr–increase) can be expressed in two models: a) in the temporal model where the ilpb deposited on the sd formation (upper cenomanian-lower turonian) indicates a specific temporal point during the major hiatus associated with subaerial exposure of the istrian karst (aswu), and; b) in the spatial model where the lpb (ist excluded), are related to a major unconformity between the uppermost cretaceous and the early palaeogene strata developed under distinctly different tectonostratigraphic constraints prevailing over the high karst area (dswu, sensu korbar, 2009). in the latter case, the rocks underlying the erosional surface show characteristics of the gh formation originally described on the island of brač (gušić & jelaska, 1990). however, tectonic deformation over the dswu are more intricate with respect to the istrian karst (aswu), except for the učka mt which was strongly affected by the latest orogenic wrench-fault tectonics (prelogović et al., 1995; prelogović et al., 2003), representing an area struck by both strike-slip and compressive tectonics (scisciani & calamita, 2009). in this regard it is worth mentioning that subaerially exposed ilpb deposits are preserved even on the učka mt about 800 m above the istrian mainland, suggesting that their immediate cover (middle eocene foraminiferal limestones; ćosović et al., 2004) has been stripped off much later prohibiting the complete removal of the ilpb by advancing denudation of the underlying cretaceous bedrock in spite of the vigorous uplift. this, together with the fact that brač island (a model for upper cretaceous formations division; gušić & jelaska, 1990) pertains to the dalmatian karst tectonostratigraphic unit (adriatic ne, or aneu, sensu korbar, 2009) (fig. 2), showing a somewhat different tectonic pattern, further complicates the clear-cut comparison of the bauxite-hosting lithologic units along the entire k–pg boundary within the adcp domain. provided that the cr–event which filtered through both the ilpb and the lpb was more or less synchronous over the entire karst dinarides during the k–pg interval, it would demonstrate different responses of the particular fragments from the adriatic and dinaric domains in croatia to the tectonic deformations caused by the differential spatial influence of the advancing dinaridic thrust front (korbar, 2009; brlek et al., 2013). 4.4. the ilpb model of the istrian karst (aswu) as mentioned earlier, results from the previous investigations concerning the bauxites on the istrian karst (aswu) (peh & kovačević galović, 2014) ought to be briefly reiterated in order to present the link to the rest of the carbonate platform more clearly. the istrian karst seems to be of particular importance since the hiatus in that part of adcp is associated with a prominent forebulge zone induced by the approaching dinaridic thrust front, bringing into direct focus the significance of the erosional vacuity. the pu-gh depositional sequences are clearly truncated forming an unconformity which is directly overlain by eocene foraminiferal limestones and occasionally by the liburnian formation, (but only in the farthest se part of the istrian peninsula). according to otoničar (2007) the initial uplift of the forebulge occurred at the end of the campanian, which resulted in differential erosion of the subaerially exposed cretaceous carbonate successions. controlled by topography, uplift, relief, rate of erosion, vacuity and total stratigraphic gap are all mutually and positively correlated (mindszenty et al., 1995) – the youngest deposits were first to emerge at the crest of a subaerially exposed forebulge and they were also the first to experience erosion. in this process, after complete destruction of the assumed campanian strata, erosional truncation advanced deeper, affecting the successively older formations. as a result of the migration of the forebulge and the progradation of the associated foreland basin system through time, away from the approaching dinaric thrust front (in conformity with the model promoted by crampton & allen, 1995, and decelles & gilles, 1996), both the age of the bedrock immediately underlying the evolved unconformity and the spread of the stratigraphic gap expanded steadily in sw direction (otoničar, 2007). in other words, the k-pg unconformity in istria is formed as a „diachronous erosion surface” (sensu yang, 2011) with the youngest bedrock formation (gh) closer to the orogenic wedge and the older formations successively further away. naturally, the development of the palaeokarst and the accumulation of the protobauxitic material began with the exhumation of the gh and were brought to an end with the pu, in reverse order with respect to their deposition. with this in mind, the aftermath of the cr–event as reflected in the df1 of the ilpb model, can be dated as postcampanian, subsequent to the erosional truncation which cut sufficiently deep to exhume the sd formation. the structure of the df1 can be attributed to the uplift-related change from phreatic to vadose conditions during karstification of the emerging forebulge similar to that reported by mindszenty et al. (2000) from the cretaceous of the transdanubian range, hungary. the originally high content of both cr and ni changes gradually in favour of cr due to the loss of ni through the process of leaching which intensified towards the crest of the forebulge during uplift. in the incipient stages of evolution of the forebulge the depositional/diagenetic environment probably favoured the settling of phreatic conditions since the newly formed low-level karst planes did not support formation of a deep unsaturated zone with unimpeded drainage. a vadose environment would have been established later when the region of the uplifting forebulge became sufficiently high (generally less than 200 m, according to crampton & allen, 1995) to permit free downward circulation of water and the appearance of streams draining the exposed highlands. that period is coeval with exhumation of the sd formation at the crest of the forebulge and subsequent redistribution of the df1 suite of elements (cr and ni in particular) in the proto-bauxite material in accordance with eh/ph conditions controlled by the position of the groundwater table (d’argenio & mindszenty, 1995). simultaneously, the diminishing trace element signal in the bauxites towards the pu and ru formations with reemerging significance of ni relative to cr may indicate a decrease in amplitude of the relief and also of the rate of erosion on the distal slope of the forebulge towards the back-bulge basin (sw istria) (otoničar, 2007) which restored phreatic conditions. also, the diagenetic environment was likely to change during the early phase of burial, turning the initially vadose conditions into phreatic ones (d’argenio & mindszenty, 1995). the fact that cretaceous formations older than late albian (pu), extending to the valanginian, are devoid of ilpb deposits, is indicative of intermittent episodes of subaerial exposure in the cretaceous. they affected relatively thin carbonate succes sions in sw istria due to recurrent brief emersions during the early creg eologia c roatica zoran peh and erli kovačević galović: geochemistry of lower palaeogene bauxites – a unique signature for the tectonostratigraphic evolution ... 277 taceous (matičec et al., 1996), which prevented the formation of bauxite deposits. it is obvious that the cr-ni polarity relationship described above represents the keynote striking the answering chord in the whole set of processes related to bauxitization in the forebulge zone during its development. in this regard, another set of geochemical processes defined by the df2 may elucidate the progressive changes and maturation of the proto-bauxitic material during the movement of the forebulge and the progressive formation of the unconformity. it is functional within the same matrix of tectonostratigraphic constraints explained by the df1, exhibiting, however, a slight shift in time. due to the reducing environment established in the early stages of the forebulge uplift (swampy lowlands across the emerged gh formation), the process of lateritization (ferralitization) of the proto-bauxitic material could not have progressed very far while chalcophile elements were coprecipitated with fe-sulfides or, as suggested from fig. 5a-b (fe2o3 opposing chalcophiles), occurring in the form of discrete metal sulfide phases (koretsky et al., 2006), with both potentially being adsorbed on clay minerals. following exhumation of the sd formation, vadose conditions were established, which reinforced the process of karstification and chemical reworking of the proto-bauxite. however, only with the emergence of the ru formation did the protobauxitic material achieve its full maturity with the removal of all mobile elements (ni was removed earlier during the sd phase) and accumulation of al, fe, and mn oxyhydroxides. finally, due to flexural subsidence in the distal parts of the forebulge, similar conditions were restored in regard to the pu formation. it was characterized by the reinstatement of the reducing environment, accommodating the same suite of components as in the initial stage of the uplift (fig. 5a-b). 4.5. integrating the models into the broader tectonostratigraphic scheme subaerial exposure of the istrian part of the aswu and associated bauxitization probably lasted until the early eocene when platform conditions were restored burying the previously formed unconformity under foraminiferal limestones (ćosović et al., 2004). a similar forebulge effect in approximately the same period was also hypothesized in the central part of the high karst (dswu) where the underlying carbonate bedrock mostly refers to the gh formation (coniacian to santonian) (korbar, 2009). however, in this area the discontinuity surface may not exhibit clear diachronism which in istria is plainly indicated by the contrasting position of cr and ni in the bauxite geochemical signature. in this sense the lpb lithofacies in a spatially confined geotectonic setting of the external dinarides (nai–cda groups) cannot be squarely associated with a specific age interval between emersion and final drowning of both the aswu and dswu. it is particularly evident in the case of lpb groups outside istria where bauxite deposits are regularly „sandwiched” between santonian (early campanian) footwall and early eocene hanging wall carbonate rocks betraying the apparent synchronicity along the entire k-pg boundary in this part of the investigated area. the proposed models demonstrate that the prominent position of the sd bauxites in istria is brought about by the bulging effect manifested in the inverse cr/ni relationship (fig. 5a-b) in a fashion previously described. however, a similar cr/ni status is missing in the lpb model where ni stands relatively close to cr (positive association) for both dalmatian groups (nda and cda) (fig. 5c-d) indicating the absence of apparent bulging in the ne part of the dswu. in all probability, the close cr/ni relationship in the easternmost portion of the dswu has been developed as a net feedback from slow uplift prohibiting effective draining and elimination of phreatic conditions which resulted in the distinctly gibbsitic character of the cda proto-bauxite material during the entire emergent stage (kovačević galović et al., 2012). both rich in cr, the aforementioned groups are, nonetheless, not quite close together with regard to their general geochemical signal, as is clearly demonstrated by mahalanobis distances (md) calculated for both models. md values locate the cda group to the far end of the lpb spatial sequence (tab. 3) while the sd group is placed somewhere in the „middle” of the ilpb temporal succession. model comparisons based on md values demonstrate that both prominent groups (sd and cda) are located farthest from their respective „reference points”, that is, the pu and ist groups, suggesting thereby the period of most intense cr-enrichment as the correlating event. when established, the general statistical reciprocity between the two bauxite lithofacies reveals (in light of the ergodic assumption), the space-time symmetry in the process of the profound geochemical change and reworking of the initial geochemical signal (input of cr/ni-rich material) across the entire adcp, that is, both its adriatic and dinaric domains (cf. fig. 5). it implies that the sd is closest in time while the cda is closest in space to the supposed cr-event (input of source material). however, it is essential that the supposed event cannot be decoupled from geochemical processes affecting the cr/ni partition in protobauxites during subaerial exposure of the karst environment. this means that the major contrast between the bauxite lithofacies from two adcp domains, exposed through divergent geochemical fates of the two dominant element pair, is defined primarily by the presence/absence of the forebulge dynamics and ensuing environmental control over the carbonate platform. last but not least, the geochemical signature of both bauxite domains (ilpb and lpb), as communicated through the all-important df1 in both coda dfms, most probably indicates the temporal inequality between the duration of subaerial exposure of istrian gh and its high karst platform-interior counterpart. 5. conclusion the origin and emplacement of lower palaeogene bauxites on the adriatic-dinaric carbonate platform was explored in light of the recent advancements in the modeling of the foreland basin systems. in the istrian part of the platform (aswu) bauxitization was coeval with expansion of the collision-induced diachronous discontinuity surface, a process assumed to have been developed under strong tectonic control (uplift of a flexural bulge) during the initial stages of orogeny. to this purpose, a discriminant function model of the ilpb compositional data (whole rock geochemical data) was constructed beforehand, providing the solid ground for the separation of bauxite samples (based on lithostratigraphic units or formations) derived from the developing subaerial exposure of the istrian cretaceous/palaeogene palaeoenvironment. attention was then paid towards finding distinctive geochemical signatures in the bauxites (lpb) from the neighbouring tectonostratigraphic unit (dswu) in order to recognize the possible development of forebulge unconformities elsewhere across the platform. a similar model of the entire adcp (based on geo graphical deployment of the bauxite groups) was adopted from earlier investigations and restructured after the principles of compositional data analysis, in order to assess the geochemical correspondence between the two event-markers (ilpb and lpb) at the same regional unconformity. the need for clarification of the nature of tectonostratigraphic constraints, especially those involved in forebulge dynamics, has occurred as a logical net effect associat ed g eo lo gi a c ro at ic a geologia croatica 69/2278 g eo lo gi a c ro at ic a with the proposed modeling of the bauxite lithofacies in terms of the spatial/temporal relationships. the most important results of these investigations can be summarized as follows: a) both models heavily rely on the importance of the first discriminant function which comprises 77.2 and 81.5% of the total variability in the ilpb and lpb models, respectively, albeit with different implications in terms of geochemical processes. in the ilpb model df1, it is interpreted as reflecting the intricate environmentally-controlled ni/cr enrichment-depletion relationship whereas in the df2 it is a supplementary process (17.1%) explained as manifesting the interchange between vadose and phreatic bauxite-forming environments due to changing redox conditions. both functions, however, appeal to the effects of intraplatform tectonic activity with the purpose of clarifying the specified geochemical controls. in the lpb model df1 the specific performance of cr is established by its complementary positioning with regards to bauxitic/clay components (primarily k2o) while the df2 (11.1%) reflects enrichment (or reduction) in al2o3 and related components typical for bauxites. b) the discontinuity surface underlying the ilpb is characterized by diachronism caused by the development of a flexural forebulge on the istrian part of the aswu. forebulge evolution is recorded in the ilpb geochemical signature by assigning to the sd bauxite group a pivotal position in the significant geochemical (cr/ni) partitioning after the initial input of source material. bauxite-hosting sd and ru formations mark the maximum possible cumulative uplift and erosion, facilitating maturation of the proto-bauxitic material under oxidizing, vadose conditions. in contrast, the pu group, formed on the distal flank of the forebulge (away from the orogenic wedge), shows evidence of the geochemical signal characteristic of reducing conditions. in the case of the lpb, the north adriatic ist and nai groups are clearly separated from the dalmatian nda and cda groups in such a manner that the latter participate as a repository for the chromium ingress from some extraneous source – most probably the dinaridic ophiolite belt). c) comparison of the ilpb and lpb models via an ergodic approach brings into the foreground the pivotal status of the sd (aswu) and cda (dswu) bauxite groups dictated by existing adcp tectonostratigraphic constraints. in light of a supposed cr–event it indicates both divergent geochemical fates of the most important descriptor variables (cr and ni) with respect to development of a flexural bulge, and the temporal inequality of the istrian gh formation (aswu) and its high karst counterpart (dswu). acknowledgment this study was supported by the ministry of science, education and sports, republic of croatia (mzos) via the former scientific project (zproject): the geological maps of the republic of croatia. their support is greatly appreciated. the authors wish to express their gratitude to the reviewers for their thoughtful suggestions and comments. thanks are also due to all who have contributed to the execution of this research. references aitchison, j. (1982): the statistical analysis of compositional data (with discussion).– j. roy. stat. soc. series b, 44, 139–177. aitchison, j. (1986): the statistical analysis of compositional data.– chapman and hall, london-new york, 416 p. doi:10.1002/bimj.4710300705 aitchison, j. (2008): the single principle of compositional data analysis, continuing fallacies, confusions and misunderstandings and some suggested remedies.– in: daunis-i-estadella, j. & martín-fernández, j.a. (eds.): proceedings of codawork’08, the 3rd compositional data analysis workshop, may 27–30, university of girona, girona (spain), 1–28. aitchison, j. & egozcue, j.j. (2005): compositional data analysis: where are we and where should we be heading?– math. geol., 37, 829–850. doi:10.1007/s11004005-7383-7 analytical methods committee (1987): recommendations for the definition, estimation and use of the detection limit.– analyst, 112, 199–204. doi:10.1039/ an9871200199 antweiler, r.c. & taylor, h.e. (2008): evaluation of statistical treatments of left-censored environmental data using coincident uncensored data sets: i. summary statistics.– environ. sci. technol., 42, 3732–3738. doi:10.1021/es071301c. balco, g. & stone, o.h.j. (2005): measuring pleistocene erosion rates with cosmogenic nuclides in buried alluvial sediment, fisher valley, southeastern utah.– earth surf. proc. land., 30, 1051–1067. doi: 10.1002/esp.1262. barceló-vidal, c., & pawlowsky-glahn, v. (1999): letter to the editor: comment on „singularity and nonnormality in the classification of compositional data“ by bohling, g.c., davis, j.c., olea, r.a. & harff, j.– math. geol., 31, 581–585. blašković, i., dragičević, i. & pokrajčić, i. (1989): tectonic control of the origin of the paleorelief of bauxite deposits in the western herzegovina, yugoslavia.– travaux icsoba, 19/22, 231–238. brlek, m., korbar, t., cvetko tešović, b., glumac, b. & fuček, l. (2013): stratigraphic framework, discontinuity surfaces and regional significance of campanian slope to ramp carbonates from central dalmatia, croatia.– facies, 59, 779–801. doi: 10.1007/s10347-012-0342-0 brlek, m., korbar, t., košir, a., glumac, b., grizelj, a. & otoničar, b. (2014): discontinuity surfaces in upper cretaceous to paleogene carbonates of central dalmatia (croatia): glossifungites ichnofacies, biogenic calcretes, and stratigraphic implications.– facies, 60, 467–487. doi:10.1007/s10347-013-0378-9. buccianti, a. (2013): is compositional data analysis a way to see beyond the illusion?– comp. geosci., 50, 165–173. doi:10.1016/j.cageo.2012.06.012. buccianti, a., mateu-figueras, g. & pawlowsky-glahn, v. (eds.) (2006): compositional data analysis in the geosciences: from theory to practice.– geol. soc. spec. publ., the geological society london, 264, 224 p. crampton, s.l. & allen, p.a. (1995): recognition of forebulge unconformities associated with early stage foreland basin development; example from the north alpine foreland basin.– aapg bull., 79, 1495–1514. cvetko tešović. b., gušić, i., jelaska, v. & bucković, d. (2001): stratigraphy and microfacies of the upper cretaceous pućišća formation, island of brač, croatia. cretaceous res., 22, 591–613. doi: 10.1006/cres.2001.0279. cvetko tešović, b., glumac, b. & bucković, d. (2011): integrated biostratigraphy and carbon isotope stratigraphy of the lower cretaceous (barremian to albian) adriatic-dinaridic carbonate platform deposits in istria, croatia.– cretaceous res., 32, 301–324. doi:10.1016/j.cretres.2010.12.011. ćosović, v., drobne, k. & moro, a. (2004): paleoenvironmental model for eocene foraminiferal limestones of the adriatic carbonate platform (istrian peninsula).– facies, 50, 61–75. doi:10.1007/s10347-004-0006-9. d’argenio, b. & mindszenty, a. (1995): bauxites and related palaeokarst: tectonic and climatic event markers at regional unconformities.– eclogae geol. helv., 88, 453–499. daunis-i-estadella, j., thió-henestrosa, s. & mateu-figueras, g. (2011): two more things about compositional biplots: quality of projection and inclusion of supplementary elements.– in: egozcue, j.j., tolosana-delgado, r. & ortego, m.i. (eds.): proceedings of the 4th international workshop on compositional data analysis (codawork’11), girona, 1–14. decelles, p.g. & giles, k.a. (1996): foreland basin systems.– basin res., 8, 105– 123. durn, g., ottner, f., tišljar, j., mindszenty, a. & barudžija, u (2003): regional subaerial unconformities in shallow-marine carbonate sequences of istria: sedimentology, mineralogy, geochemistry and micromorphoplogy of associated bauxites, paleosols and pedo-sedimentary complexes. field trip p8, 209-254.– in: vlahović, i. & tišljar, j. (eds): field trip guidebook of 22nd ias meeting of sedimentology, opatija, 256 p. egozcue, j.j. & pawlowsky-glahn, v. (2006): simplicial geometry for compositional data.– in: buccianti, a., mateu-figueras, g. & pawlowsky-glahn, v. (eds): compositional data analysis in the geosciences: from theory to practice. london: geol. soc. spec. publ., 264, 145–158. galović, l. & peh, z. (2016): mineralogical discrimination of the pleistocene loess/ paleosol sections in srijem and baranja, croatia.– aeolian res., in press. doi: 10.1016/j.aeolia.2016.04.006 gušić, i. & jelaska, v. (1990): stratigrafija gornjokrednih naslaga otoka brača u okviru geodinamske evolucije jadranske karbonatne platforme (upper cretaceous stratigraphy of the island of brač within the geodynamic evolution of the adriatic carbonate platform).– djela jugoslavenske akademije znanosti i umjetnosti, 69, institut za geološka istraživanja, zagreb, 160 p. g eologia c roatica zoran peh and erli kovačević galović: geochemistry of lower palaeogene bauxites – a unique signature for the tectonostratigraphic evolution ... 279 hinsbergen, d.j.j., mensink, m., langereis, c.g., maffione, m., spalluto, l., tropeano, m. & sabato, l. (2014): did adria rotate relative to africa?– solid earth, 5, 611–629. doi:10.5194/se-5-611-2014 hrvatski geološki institut (croatian geological survey) (2009): geološka karta republike hrvatske 1:300000 (geological map of the republic of croatia 1:300000), zagreb. korbar, t. (2009): orogenic evolution of the external dinarides in the ne adriatic region; a model constrained by tectonostratigraphy of upper cretaceous to paleogene carbonates.– earth-sci. rev., 96, 296–312. doi: 10.1016/j.earscirev.2009.07.004. korbar, t., glumac, b., cvetko tešović, b. & cadieux, s.b. (2012): response of a carbonate platform to the cenomanian–turonian drowning and oae 2: a case study from the adriatic platform (dalmatia, croatia).– j. sediment. res., 82, 163–176. doi: 10.2110/jsr.2012/17 koretsky, c.m., haas, j.r., miller, d, & ndenga, n.t. (2006): seasonal variations in pore water and sediment geochemistry of littoral lake sediments (asylum lake, mi, usa).– geochemical t., 7/11, 1–26. doi:10.1186/1467-4866-7-11 kovačević galović, e., ilijanić, n., peh, z., miko, s. & hasan, o. (2012): geochemical discrimination of early palaeogene bauxites in croatia.– geol. croat, 65, 53–65. doi: 104154/gc.2012.04 márton, e., drobne, k., ćosović, v. & moro, a. (2003): palaeomagnetic evidence for tertiary counterclockwise rotation of adria.– tectonophysics, 377, 143–156. doi:10.1016/j.tecto.2003.08.022 márton, e., zampieri, d., grandesso, p., ćosović, v. & moro, a. (2010): new cretaceous paleomagnetic results from the foreland of the southern alps and the refined apparent polar wander path for stable adria.– tectonophysics, 480, 57–72. doi:10.1016/j.tecto.2009.09.003 márton, e., zampieri, d., kázmér, m., dunkl, i. & frisch, w. (2011): new paleocene–eocene paleomagnetic results from the foreland of the southern alps confirm decoupling of stable adria from the african plate.– tectonophysics, 504, 89–99. doi:10.1016/j.tecto.2011.03.006. matičec, d. (1994): neotectonic deformations in western istria, croatia.– geol. croat., 47/2, 199–204. matičec, d., vlahović, i., velić, i. & tišljar, j. (1996): eocene limestones overlying lower cretaceous deposits of western istria (croatia): did some parts of present istria form land during the cretaceous?– geol. croat., 49, 117–127. matičec, d., fuček, l., palenik, d. & oštrić, n. (2013): geological setting of the istrian county.– in: miko, s., kruk, b., dedić, ž., kruk, lj., peh, z., kovačević galović, e. & gabrić, a. (eds.): mining-geological study of potentiality and mineral resources management in the area of istrian county.– croatian geological survey, zagreb, croatia, 19–48. (in croatian). mindszenty, a., d’argenio, b. & aiello, g. (1995): lithospheric bulges recorded by regional unconformities. the case of mesozoic – tertiaty apulia.– tectonophysics, 252, 137–161. mindszenty, a., csoma, a., török, á., hips, k. & hertelendi, e. (2000): flexura jellegű előtéri deformációhoz köthető karsztbauxitszintek a dunántúliközéphegységben (rudistid limestones, bauxites, paleokarst and geodynamics. the case of the cretaceous of the transdanubian range).– bull. geol. soc. hung., 131/1–2, 107–152 (in hungarian with ext. english abstract). nocquet, j.-m. (2012): present-day kinematics of the mediterranean: a comprehensive overview of gps results.– tectonophysics, 579, 220–242. doi: 10.1016/j. tecto.2012.03.037. otoničar, b. (2007): upper cretaceous to paleogene forbulge unconformity associated with foreland basin evolution (kras, matarsko podolje and istria; sw slovenia and nw croatia).– acta carsologica, 36/1, 101–120. otoničar, b. (2008): evolution of paleokarst related to a forebulge unconformity; an example from the late cretaceous and paleogene of kras, matarsko podolje and istria, southwest slovenia and northwest croatia.– in: sasowsky, i.d., feazel, c.t., mylroie, j.e., palmer, a.n. & palmer, m.v (eds): karst from recent to reservoirs, karst waters institute special publication 14, leesburg, virginia, 221 p. paine, a.d.m. (1985): ‘ergodic’ reasoning in geomorphology: time for a review of the term? – prog. phys. geog., 9, 1–15. doi: 10.1177/030913338500900101. pamić, j, balen, d. & herak, m. (2002): origin and geodynamic evolution of late paleogene magmatic associations along the periadriatic–sava–vardar magmatic belt.– geodin. acta, 15, 209–231. pawlowsky-glahn, v. & egozcue, j.j. (2006): compositional data and their analysis: an introduction.– in: buccianti a, mateu-figueras, g. & pawlowsky-glahn, v. (eds): compositional data analysis in the geosciences: from theory to practice. geol. soc. spec. publ., 264, 1–10. doi: 10.1144/gsl. sp.2006.264.01.01 peh, z. & halamić, j. (2010): discriminant function model as a tool for classification of stratigraphically undefined radiolarian cherts in ophiolite zones.– journal. geochem. explor., 107, 30–38. doi: 10.1016/j.gexplo.2010.06.003. peh, z. & kovačević galović, e. (2014): geochemistry of istrian lower palaeogene bauxites – is it relevant to the extent of subaerial exposure during cretaceous times?– ore geol rev., 63, 296–306. prelogović, e., kuk, v., jamičić, d., aljinović, b. & marić, k. (1995): seizmotectonic activity of the kvarner area (in croatian).– in: vlahović, i., velić, i. & šparica, m. (eds.): proceedings of the first croatian geological congress, vol. 2., croatian geological society and institute of geology, zagreb, 487–490. prelogović, e., pribičević, b., ivković, ž., dragičević, i., buljan, r. & tomljenović, b. (2003): recent structural fabric of the dinarides and tectonically active zones important for petroleum-geological exploration in croatia.– nafta, 55, 155–161. reimann, c., filzmoser, p., fabian, k., hron, k., birke, m., demetriades, a., dinelli, e. & ladenberger, a. & the gemas project team (2012): the concept of compositional data analysis in practice – total major element concentrations in agricultural and grazing land soils of europe.– sci total. environ., 426, 196–210. doi: 10.1016/j.scitotenv.2012.02.032. sakač, k. & šinkovec, b. (1991): the bauxites of the dinarides. travaux icsoba, 20–21, 1–11. schmid, s. m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpinecarpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss j geosci, 101, 139–183. scisciani, v. & calamita, f. (2009): active intraplate deformation within adria: examples from the adriatic region.– tectonophysics, 476, 57–72. doi: 10.1016/j. tecto.2008.10.030. statsoft, inc. (2006): statistica (data analysis software system), releaase 7.1; www.statsoft.com2006 steuber, t., korbar, t., jelaska, v. & gušić, i. (2005): strontium-isotope stratigraphy of upper cretaceous platform carbonates of the island of brač (adriatic sea, croatia): implications for global correlation of platform evolution and biostratigraphy.– cretaceous res., 26/5, 741–756. šinkovec, b. (1973): the origin of early palaeogene bauxites of istria, yugoslavia.– travaux icsoba, 3, 151–164. šinkovec, b. & sakač, k. (1982): the paleogene bauxites of dalmatia.– travaux icsoba, 12, 293–331. šinkovec, b. & sakač, k. (1991): bauxite deposits of yugoslavia – the state of the art.– acta geol. hung., 34/4, 307–315. šumanovac, f. (2010): lithosphere structure at the contact of the adriatic microplate and the pannonian segment based on the gravity modelling.– tectonophysics, 485, 94–106. doi:10.1016/j.tecto.2009.12.005 tarvainen, t., reeder, s. & albanese, s. (2005): database management and map production.– in: salminen, r., batista, m.j., bidovec, m., demetriades, a., de vivo, b., de vos, w., duris, m., gilucis, a., gregorauskiene, v., halamić, j., heitzmann, p., jordan, g., klaver, g., klein, p., lis, j., locutura, j., marsina, k., mazreku, a., o’connor, p.j., olsson, s.å., ottesen, r.-t., petersell, v., plant, j,a,, reeder, s,, salpeteur, i,, sandström, h., siewers, u., steenfelt, a. & tarvainen, t. (eds): geochemical atlas of europe, part 1, background information, methodology and maps. espoo: geological survey of finland, 1–4. tišljar, j., vlahović, i., velić, i., matičec, d. & robson, j. (1998): carbonate facies evolution from the late albian to middle cenomanian in southern istria (croatia): influence of synsedimentary tectonics and extensive organic carbonate production.– facies, 38, 37–151. tolosana-delgado, r., otero, n. & pawlowsky-glahn, v. (2005): some basic concepts of compositional geometry.– math. geol., 37, 673–680. doi: 10.1007/s11004-005-7374-8. tolosana-delgado, r. (2012): uses and misuses of compositional data in sedimentology.– sediment. geol., 280, 60–79. doi: 10.1016/j.sedgeo.2012.05.005. ustaszewski, k., kounov, a., schmid, s.m., schaltegger, u., krenn, e., frank, w. & fügenschuh, b. (2010): evolution of the adria-europe plate boundary in the northern dinarides: from continent-continent collision to back-arc extension, tectonics, 29, tc6017. doi:10.1029/2010tc002668 velić, i., tišljar, j., matičec, d. & vlahović, i. (1995): a review of the geology of istria.– in: vlahović, i. & velić, i. (eds): excursion guidebook, first croatian geological congress, croatian geological society and institute of geology, 21–30. vlahović, i. (1999): carbonate facies of shallow water depositional systems from kimmeridgian to late albian in western istria:– unpubl. phd thesis (in croatian with english summary).– university of zagreb, 327 p. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeogr. palaeocl., 220, 333–360. doi: 10.1016/j.palaeo.2005.01.011. yang, y. (2011): tectonically-driven underfilled–overfilled cycles, the middle cretaceous in the northern cordilleran foreland basin.– sediment. geol., 233, 15–27. doi: 10.1016/j.sedgeo.2010.10.002.  geochemical characterization and environmental status of makirina bay sediments (northern dalmatia, republic of croatia)  komar darja1*, dolenec matej1, lambaša belak živana2, matešić sanja slavica2, lojen sonja3, kniewald goran4, vrhovnik petra1, dolenec tadej1 and rogan šmuc nastja1 1 department of geology, faculty of natural sciences and engineering, university of ljubljana, aškerčeva 12, 1000 ljubljana, slovenia (corresponding author: komar.darja@gmail.com; darja.komar@ntf.uni-lj.si) 2 department of environment and municipal affairs, trg pavla šubica i no. 2, 22000 šibenik, croatia 3 department of environmental sciences, jožef stefan institute, jamova cesta 39, 1000 ljubljana, slovenia 4 ruđer bošković institute, bijenička 54, 10000 zagreb, croatia doi: 10.4154/gc.2015.06 abstract this research focuses on determination of the mineralogical composition, geochemical characteristics and evaluation of pollution status of the makirina bay sediments. calculated enrichment factor (ef) values show no enrichment (< 1) for cd, ni, and zn, minor enrichment (< 3) for as, cu, and pb, and minor to moderate enrichment for mo. the results of the sequential leaching procedure for the aforementioned potentially toxic elements (pte) indicates that the mobility and bioavailability characteristics of the pte studied declined in the following order: mo > cd > pb > ni > zn > cu > as. principal component analysis (pca) and correlation analysis confirmed the pte distribution depends mainly on the geogenic mineral components and anthropogenic activities in the areas surrounding the bay. calculated transfer factor (tf) values from sediment to seagrass cymodocea nodosa (c. nodosa) were < 1, showing that despite the results of the sequential extraction procedure, pte transfer from sediment to roots was not effective. keywords: makirina bay sediments (republic of croatia), potentially toxic elements (pte), enrichment factor (ef), sequential extraction procedure, transfer factor (tf), seagrass cymodocea nodosa geologia croaticageologia croatica geologia croatica 68/1 79–92 7 figs. 4 tabs. zagreb 2015 1. introduction sediments in aquatic ecosystems serve as one of the major reservoirs for various pollutants including essential and nonessential trace elements (ebrahimpour & mushrifah, 2008, ahmed et al., 2010, gao et al., 2010, liu et al., 2011, satpathy et al., 2012, zhang et al., 2012). trace elements are among the most persistent contaminants in sediments and potentially toxic elements (pte), in particular, have the potential to be toxic to biota (ebrahimpour & mushrifah, 2008, ahmed et al., 2010). pte can bioaccumulate in living tissue and might pose a risk to organisms in higher concentrations. pte such as cu, mo, ni, and zn are considered to be essential for the growth of organisms, but can produce a toxic effect when their intake is excessive, whereas as, cd, and pb are pte with no biological function and are toxic even in trace amounts (öztürk et al., 2009, qui et al., 2011, pereira majer et al., 2014). geochemical studies of marine sediments are therefore necessary to determine the extent of pte contamination and to estimate the quality of the entire aquatic environment. geologia croatica 68/1geologia croatica 80 the physical and chemical behaviour of pte in the environment strongly depends on their chemical forms or binding type (tessier et al., 1979, li et al., 2000, yu et al., 2001, yuan et al., 2004, ebrahimpour & mushrifah, 2008, yan et al., 2010) and can be determined by various sequential extraction procedures (tessier et al., 1979, filgueiras et al., 2002, sahuquillo et al., 2003, dean, 2007, rao et al., 2008). the results obtained from the sequential leaching procedure provide important information about the mobility of pte in sediments (li et al., 2001). several geochemical studies of makirina bay (republic of croatia) sediments have been undertaken in previous years (šparica et al., 1989, vreča, 1998, dolenec et al., 2002, lojen et al., 2004, vreča & dolenec, 2005, šparica et al., 2005, miko et al., 2007, miko et al., 2008). according to their organoleptic properties these sediments are treated as peloid or healing mud and could be used as a virgin material for various therapeutic purposes (šparica et al., 1989). the previous researches were mainly focused on measurements of the total element concentrations in surface (0–5 cm) sediments.unfortunately, determination of the total element content in sediments cannot provide sufficient information about pte mobility, bioavailability, and consequently the assessment of the environmental risk to the marine ecosystem (li et al., 2001, ebrahimpour & mushrifah, 2008, gao et al., 2010, zhang et al., 2012). figure 1: location map of makirina bay with sampling sites (dof 1:5000, dgu croatia). komar et al.: geochemical characterization and environmental status of makirina bay sediments (northern dalmatia, republic of croatia) geologia croatica 81 therefore the main aims of our research were (1) to determine the basic physico-chemical characteristics of the makirina bay sediments, (2) to determine the total major and trace element concentrations in sediment cores (0–25 cm), (3) to analyse pte chemical speciation, (4) to calculate pte enrichment factors (ef), and (5) to define the pte transfer factor (tf) from sediment to seagrass c. nodosa. 2. material and methods 2.1. study area makirina bay is located in n dalmatia (republic of croatia), 18 km nw of šibenik city (fig. 1). it is a relatively small bay, approximately 1250 m in length and 300 m in width. the depth of the sea rarely exceeds 0.5 m in the southern part of the bay and increases in the seaward direction to a depth of 4.5 m. the surroundings of the bay are cultivated (olives, gardens, vineyards) and sparsely populated. the only larger settlement near makirina bay is pirovac city, with approximately 2000 inhabitants, located on the e side of pirovac bay. along the s coast of the bay, the road connects the main land and murter island. the wider area of makirina is mostly composed of early and late cretaceous carbonate rocks and quaternary sediments (šparica et al., 1989). 2.2. sampling sediment core samples were taken in summer 2010 from 10 different sites in the central part of the bay (fig. 1). samples were collected with hand-driven plexiglass core samplers (50 cm long, 5 cm inner diameter) and were immediately frozen until further analysis was possible. in the laboratory, cores were divided into 5-cm-long sections and air-dried. before the mineralogical and geochemical analyses, nonrepresentative debris (large rocks and organic debris) was removed by wet sieving. samples were homogenized to a fine powder (<63 μm) in an agate mortar. samples of seagrass c. nodosa were handpicked in the central part of the bay in the same location as the sediment cores (fig. 1) at a depth of about 0.5 m and transferred to polyethylene bags. in the laboratory, seagrass samples were washed in distilled water. sediments and epiphytes were carefully removed from the samples with a nylon brush. seagrass individuals were dissected into two different compartments: belowground (roots and rhizomes) and above ground bio mass (leaves). plant samples were dried to a constant weight and then ground and homogenized to a fine powder in an agate mill. 2.3. analysis 2.3.1. grain size analysis the granulometric composition of the sediment was determined by a combination of wet sieving and laser diffractometry with a malvern mastersizer s (fraction<125 µm) at salonit anhovo d.d., slovenia. grain size boundaries were calculated using the gradistat 8.0 program developed by blott & pye (2001, 2012). 2.3.2. ph, eh,and elemental (tc, corg, ts) analysis ph and redox potential (eh) were measured in a separate core immediately after coring. a combined glass electrode connected to a ph-eh meter (mettler toledo, ph ±0.01) was used for ph measurements and an inlab redox micro-electrode for eh measurements. total carbon (tc), sulfur (ts), and organic carbon (corg) contents were analysed by a leco carbon-sulfur analyser in a certified commercial canadian laboratory (acme analytical laboratories). loss on ignition (loi) is by weight difference after ignition at 1000°c. 2.3.3. mineralogical analysis the mineralogical composition of sediments was carried out at the faculty of natural sciences and engineering, department of geology, ljubljana (slovenia) via x-ray powder diffraction (xrd) using a philips pw3710 x-ray diffractometer. diffraction patterns were identified with the x‘pert highscore plus program and rietveld method. 2.3.4. major and trace element concentrations in sediment and seagrass geochemical analysis of sediments was carried out in a certified commercial canadian laboratory (acme analytical laboratories) by extraction for 1 h with 2-2-2-hcl-hno3h2o at 95°c by inductively coupled plasma mass spectrometry (icp-ms). the analytical precision and accuracy were better than ±5% for the investigated elements. this was assessed with in-house reference materials (std so-18) and by the results of the duplicate measurements of six sediment samples as well as duplicate measurements of reference material samples. the geochemical composition of seagrass samples was determined in the certified commercial laboratory actlabs (activation laboratories, canada) by high resolution icpms and microwave digestion. dry, ashed samples were dissolved in acid (aqua regia solution). the quality of the analysis was assessed using standard materials nist 1575a. measurements of samples were also duplicated. the results indicated that the analytical precision and accuracy were within ±10% for the analysed elements. 2.3.5. assessment of sediment pollution the extent of sediment contamination with pte was assessed by the enrichment factor (ef) calculation (birth, 2003, chen et al., 2007, varol, 2011, ghrefat et al., 2011). ef is defined as follows: ef=(pte/al)sample/(pte/al)background. ef values were interpreted as suggested by birth (2003) and chen et al. (2007) (table 1). in this study aluminium (al) was used as the reference element for geochemical normalization. pte to al ratios are widely adopted, presumably because the concentrations of al in weathering products and their parent material are generally com pa rable (zhang & liu, 2002). for background values, mean concentrations of pte in the surficial sediment of the central adriatic were applied (dolenec et al., 1998, žvab rožič et al., 2012). geologia croatica 68/1geologia croatica 82 2.3.6. sequential extraction procedure one sediment core was selected for the chemical partitioning analysis of as, cd, cu, pb, mo, ni, and zn by employing an sequential extraction procedure in acme analytical laboratories, canada. the sediment samples, weighing 1 g, were placed in screw-top test tubes. to each sample, 10 ml of leaching solution was added. afterwards, the caps were screwed on and the tubes were subjected to the appropriate extraction procedure, depending on the stage of the leaching. within this procedure the sequential extraction scheme included a water soluble fraction (f1), an exchangeable and carbonate bound fraction (f2), an organic (oxidizable) fraction (f3), a reducible fraction (f4) and a reducible + residual fraction (f5). reagents used per one gram of sample were f1 – demineralized water, f2 – 1m ammonium acetate, f3 – 0.1m sodium pyrophosphate, f4 – 0.1m (cold) hydroxylamine hydrochloride and f5 – 0.25m (hot) hydroxylamine hydrochloride. after the sequential extraction procedure, the concentration of the analysed elements in the solutions was measured by perkin elan 6000 icp-ms for the determination of 60 or more elements. a qa/qc protocol incorporated a sample duplicate to monitor the analytical precision, a reagent blank was used to measure the background, and an aliquot of inhouse reference material to monitor appropriate accuracy. for sketching the graphs we replaced the values below the detection limit (lod) with lod/ 2 (verbovšek, 2011). 2.3.7. transfer factor (tf) calculation to evaluate the transfer of pte from sediment to seagrass c. nodosa, the transfer factor (tf) was calculated as follows: tf=cplant/csediment or water (dean, 2007). the higher the tf value, the more mobile and available the pte (dean, 2007). according to kalfakakou & akrida-demertzi (2000), tf >1 indicates pte bioaccumulation. 2.3.8. statistical test pearson r correlation analyses were applied to ascertain any associations between elements determined in the makirina bay sediments. basic statistical analyses, box plots, and statistical calculations mentioned above were performed using the statistica 10 software program. a principal component analysis (pca) was conducted in order to group major and trace elements. aitchison table 1: enrichment categories. ef value extent of enrichment according to calculated ef ef < 1 no enrichment ef< 3 minor enrichment 3 < ef < 5 moderate enrichment 5 < ef < 10 moderately severe enrichment 10 < ef < 25 severe enrichment 25 < ef < 50 very severe enrichment ef > 50 extremely severe enrichment (1981, 1986) showed that the effects of the constant-sum constrain (csc) on covariance and correlation matrices disappear if the raw percentage data are expressed as logarithms of ratios. consequently we used centred log-ratio transformation. 3. results and discussion 3.1. basic sediment characteristics 3.1.1. corg, tc, ts, ph and eh the corg content in the makirina bay sediments varies from 4.08 to 5.53%. in the surface sediment of the central adriatic, the value of corg is estimated to be 0.95% (dolenec et al., 1998). relatively high corg concentrations in the makirina bay sediments are related to the accumulation of organic material associated with the decomposition of aquatic plants abundant in the makirina bay (vreča et al., 1998). corg does not show any specific trend with depth in sediment cores, while tc concentrations (5.47 to 12.32%) show a general decrease (fig. 2) associated with higher quantities of the detrital fraction in the upper part of sediment cores. ts concentrations are also very high (1.22–2.59%), indicating a general increase with depth (fig. 3), similar to the presence of the mineral pyrite in sediments. results of eh measurement showed a highly reductive sedimentary environment even at the sediment/water interference (eh= –430 mv). negative eh values and slightly decreasing ph (ranging from 7.95 to 6.94), are attributed to processes accompanying the decomposition of sedimentary organic matter (lojen et al., 2004). in recent anoxic marine sediment, ph is also controlled by the precipitation of metal sulfides (ben-yaakov, 1973), pyrite in the case of the makirina bay sediments. 3.1.2. grain size distribution the granulometric analysis of the makirina bay sediments showed that they are mostly represented by very poorly sorted figure 2: vertical distribution of tc concentrations. komar et al.: geochemical characterization and environmental status of makirina bay sediments (northern dalmatia, republic of croatia) geologia croatica 83 figure 3: vertical distribution of ts concentrations. sandy silt (fig. 4). in all sediment samples, mud (silt+clay) dominates over sand, indicating a relatively calm depositional environment (šparica et al., 1989, šparica et al., 2005). the average sand content is 27% with the major proportion (41%) in the top 5 cm of sediment cores while the average content of mud is 73% with the minor proportion (59%) in the top 5 cm of sediment cores. mean values of grain sizes ranged from 40 µm (top 5 cm of sediment cores) to 20 µm (bottom 5 cm of sediment cores). 3.1.3. mineralogy according to xrd analysis, the mineral composition of the makirina bay sediments is characterized by high quantities of dolomite and quartz, followed by illite/muscovite, aragonite, halite, calcite, and pyrite. in some sediment samples, magnesium calcite, plagioclase, gypsum, and clinochlore were also determined. carbonate minerals predominate among the established mineral assemblage, which is in accordance with the catchment geology of the study area, where ivinj dolomites, makirina limestones and dolomites, kamena rudist limestones and ivinj draga deluvial deposits lithostratigraphic units may be discerned (šparica et al., 1989, šparica et al., 2005). 4. core sediment geochemistry 4.1. major elements mean concentrations of major elements are presented in table 2. the concentration of si in the makirina bay sediments ranges from 9.34 to 21.84% and indicates a slightly increasing trend with depth in the sediment cores, visible mostly in figure 4: granulometric composition of the makirina bay sediments, diagram developed by blott & pye (2001, 2012). geologia croatica 68/1geologia croatica 84 ta bl e 2: m ea n co nc en tr at io ns o f m aj or a nd tr ac e el em en ts in m ak iri na b ay se di m en ts . c on ce nt ra tio ns in it al ic le tt er s r ep re se nt m in im um v al ue s, co nc en tr at io ns in b ol d le tt er s r ep re se nt m ax im um v al ue s ( *d o le n ec e t al ., 1 99 8, * * žv a b ro ži č et a l., 2 01 2) . d ep th [c m ] si [% ] a l [ % ] k [% ] ca [% ] m g [% ] fe [% ] n a [% ] m n [% ] p [% ] ti [% ] 0– 5 12 .6 5 4. 33 1. 23 11 .3 2 3. 11 2. 26 2. 45 0. 02 0. 03 0. 26 5– 10 14 .6 6 5. 32 1. 38 9. 11 3. 30 2. 80 2. 46 0. 02 0. 03 0. 32 10 –1 5 15 .6 5 5. 92 1. 49 8. 25 3. 20 3. 11 2. 07 0. 03 0. 03 0. 35 15 –2 0 15 .5 4 5. 93 1. 50 8. 57 2. 95 3. 15 1. 91 0. 03 0. 03 0. 35 20 –2 5 15 .9 8 5. 80 1. 46 9. 29 2. 97 3. 08 1. 90 0. 03 0. 03 0. 35 m ea n 14 .9 5. 46 1. 41 9. 31 3. 11 2. 88 2. 16 0. 03 0. 03 0. 33 ce nt ra l ad ria tic * m ea n va lu e 4. 35 1. 41 12 .5 6 2. 32 2. 62 0. 12 0. 05 0. 2 ce nt ra l ad ria tic ** m ea n va lu e 3. 73 0. 77 1. 23 d ep th a g [p pm ] a s [ pp m ] a u [p pb ] ba [p pm ] be [p pm ] bi [p pm ] cd [p pm ] co [p pm ] cr [p pm ] cu [p pm ] cs [p pm ] g a [p pm ] h f [ pp m ] h g [p pm ] m o [p pm ] n i [ pp m ] 0– 5 0. 08 14 .4 7 1. 62 14 2. 94 1. 60 0. 19 0. 27 7. 05 82 .1 0 27 .6 4 4. 87 8. 32 3. 38 0. 07 13 .8 2 26 .5 1 5– 10 0. 09 15 .5 9 1. 47 16 8. 31 1. 48 0. 26 0. 25 8. 79 96 .6 4 30 .7 4 5. 51 10 .0 9 4. 23 0. 07 22 .5 6 31 .8 6 10 –1 5 0. 09 16 .4 5 2. 18 18 5. 63 2. 14 0. 31 0. 31 9. 95 10 5. 19 34 .1 0 6. 20 11 .3 8 4. 33 0. 07 25 .1 4 34 .9 3 15 –2 0 0. 08 17 .4 1 1. 86 18 9. 00 3. 00 0. 33 0. 33 10 .7 8 11 9. 73 31 .2 9 6. 38 11 .8 3 4. 31 0. 07 31 .5 4 37 .8 6 20 –2 5 0. 08 17 .3 7 3. 47 18 4. 43 2. 10 0. 26 0. 27 10 .0 4 11 3. 38 23 .0 6 6. 13 10 .9 3 4. 43 0. 07 32 .6 9 35 .2 7 m ea n 0. 08 16 .2 6 2. 12 17 4. 06 2. 06 0. 27 0. 28 9. 32 10 3. 41 29 .3 6 5. 82 10 .5 1 4. 14 0. 07 25 .1 5 33 .2 9 ce nt ra l ad ria tic * m ea n va lu e 0. 8 10 .5 19 0 1. 9 16 11 5 24 .7 0. 11 3 11 1 ce nt ra l ad ria tic ** m ea n va lu e 0. 07 1. 06 d ep th pb [p pm ] rb [p pm ] sb [p pb ] sc [p pm ] se [p pm ] sn [p pm ] sr [p pm ] ta [p pm ] th [p pm ] tl [p pm ] u [p pm ] v [p pm ] w [p pm ] y [p pm ] zn [p pm ] zr [p pm ] 0– 5 23 .7 4 68 .8 8 0. 28 7. 23 1. 18 2. 36 49 6. 44 0. 72 8. 60 0. 45 6. 16 80 .2 3 1. 01 17 .2 0 47 .6 7 12 0. 29 5– 10 27 .0 1 84 .7 9 0. 34 8. 94 1. 14 2. 75 33 5. 28 0. 89 10 .8 6 0. 58 9. 01 10 3. 38 1. 53 21 .3 3 48 .5 0 15 0. 02 10 –1 5 27 .2 9 93 .4 4 0. 34 10 .0 0 1. 16 2. 63 30 0. 15 0. 94 11 .8 3 0. 63 9. 70 11 1. 13 1. 56 23 .5 8 50 .6 3 16 0. 58 15 –2 0 27 .3 5 96 .6 9 0. 39 9. 88 1. 04 2. 75 32 8. 95 0. 94 12 .0 9 0. 66 10 .8 0 11 3. 88 1. 56 23 .8 8 50 .6 3 16 1. 01 20 –2 5 25 .3 1 92 .0 6 0. 43 10 .0 0 0. 91 3. 71 36 8. 86 0. 87 11 .7 7 0. 65 10 .8 9 11 0. 00 1. 51 24 .3 7 46 .5 7 16 6. 89 m ea n 26 .1 4 87 .1 7 0. 35 9. 21 1. 09 2. 84 36 5. 94 0. 87 11 .0 3 0. 60 9. 31 10 3. 72 1. 43 22 .0 7 48 .8 0 15 1. 76 ce nt ra l ad ria tic * m ea n va lu e 11 9. 6 58 4 6. 4 2. 1 89 73 38 .9 komar et al.: geochemical characterization and environmental status of makirina bay sediments (northern dalmatia, republic of croatia) geologia croatica 85 the upper 15 cm. si levels in the sediment are higher than si concentrations in the surface sediments of the central adriatic (žvab rožič et al., 2012). relatively high concentrations of sio2 are related to the presence of quartz originating from the eocene flysch located approximately 6 km ne of makirina (šparica et al., 2005). this is supported by a positive correlation of si, zr, and cr (table 3), showing their common source. si in the sediment could also originate from ”terra rossa”, a typical mediterranean red soil developed in the surroundings of the bay (vreča, 1998). al and k concentrations in the makirina bay sediments range from 2.99 to 8.31% and from 0.99 to 2.11%, respectively. concentrations of al and k in the makirina bay sediments are higher than their respective concentrations in the surface sediments of the central adriatic (dolenec et al., 1998). the distribution of al and k and a strong positive correlation between the al and k concentrations (table 3) suggest that these two elements have similar origins and depositional characteristics. concentrations of both elements indicate a slightly increasing trend with depth of the sediment cores, visible mostly in the upper 15 cm, confirming the presence and distribution of clay minerals (illite/muscovite and clinochlore) in these cores. the concentration of ca and mg in the makirina bay sediments varies from 3.67 to 14.84% and from 2.07 to 3.90%, respectively. concentrations are more or less the same as the concentration of ca and mg in the surface sediments of the central adriatic (dolenec et al., 1998). relatively high concentrations of ca and mg in the sediments of the central adriatic probably suggest the enrichment of sediments with predominantly detrital calcite and dolomite, carried into the basin from the land (dolenec et al., 1998). ca has a strong positive correlation with sr (table 3) which is related to their similar geochemical behaviour. sr is often a substitute for ca because their ionic radii are fairly similar. a negative correlation or lack of correlation between ca, mg, and the majority of the trace elements (table 3) confirms the important role of other minerals (for example silicates) as the geochemical carrier phase of trace elements. fe concentrationsin the makirina bay sediments varied from 1.59 to 4.35%. the fe content in sediments is higher than that in the surface sediment of the central adriatic (dolenec et al., 1998).the vertical profiles of fe in the sediments show exactly the same pattern as al. a strong positive correlation between fe, al, and k (table 3) suggests that fe is principally associated with the clay minerals. iron is also present in sulfide form as authigenic pyrite, which is also supported by the positive correlation between fe and ts (table 3). na concentrations in the makirina bay sediments range between 0.78 and 3.78%. na content in the sediments is related to the presence of the halite mineral. concentrations of na in the makirina bay sediments are higher than the na content in surface sediments of the central adriatic (žvab rožič et al., 2012) because of the semi-enclosed character and evaporitic environment of the study area (dolenec et al., 2002). the concentrations of mn range between 0.02 and 0.04%. concentrations obtained in this study are lower than those in the surface sediments of the central adriatic (dolenec et al., 1998). its concentrations reflect redox conditions. in oxygen rich sediments, manganese is accumulated as oxides, whereas in oxygen depleted sediment the reduction and solubilization of these oxides can release mn to pore waters (monteiro et al., 2012). the concentrations of total p varied from 0.02 to 0.05%. these concentrations are more or less the same as the concentrations of p in the surface sediment of the central adriatic (dolenec et al., 1998). there is no significant correlation between p and other elements present (table 3). p enrichment in the top 5 cm of sediment cores could be related to the phosphorus fertilizers applied in the surroundings of the bay. p may be present in marine sediments either as a detrital inorganic phosphate mineral or as phosphate ions in association with various sediment compounds. concentrations of p could also be related to the presence of the mineral apatite in the makirina bay sediments (šparica et al., 2005). the content of ti in the makirina bay sediments varied from 0.17 to 0.47%. the concentrations are higher than their respective concentrations in the surface sediments from the central adriatic (dolenec et al., 1998). the high positive correlation with al and k (table 3) indicates its relationship with clay minerals. ti concentrations indicate a downcore increase that coincides with the vertical profile of the clay minerals. concentrations of ti in the sediments could also be related to the presence of the mineral rutile (šparica et al., 2005). 4.2. trace elements the mean concentrations of trace elements in sediment profiles are presented in table 2. concentrations of most trace elements are generally higher in the bottom (20–25 cm) than in the top (0–5 cm) of the sediment cores. mean concentrations of ag, co, cr, hg, ni, sc, sr, and zn in the makirina bay sediments do not exceed their respective concentrations in the surface sediments of the central adriatic, while the mean values of as, be, cu, pb, th, u, v, and zr do exceed them (dolenec et al., 1998). this is related to the different source materials of the sediments (be, th, zr), anoxic conditions in makirina bay sediments (v, u), agricultural activity surrounding the makirina bay (as, cu), and the vicinity of the main road (pb). higher values of trace elements in the makirina bay sediments in comparison to the surface sediment of the central adriatic (dolenec et al., 1998, žvab rožič et al., 2012) could also be attributed to the calm depositional environment in makirina bay. downcore concentrations of the majority of trace elements, including ba, co, ni, v, and zr (table 2), indicate a similar distribution to al, k, and fe, suggesting their associations with clay minerals. this is supported by the strong positive correlation noted between al, k, fe, and the trace elements mentioned above. geologia croatica 68/1geologia croatica 86 ta bl e 3: t he p ea rs on c or re la tio n m at rix a na ly si s b et w ee n m aj or a nd tr ac e el em en ts (m ar ke d co rr el at io ns a re si gn ifi ca nt a t p < 0 .0 5) .   si al fe m g ca n a k ti p m n cr lo i ba co sr u v zr to t/ c to t/ s m o cu pb zn n i as cd si 1. 00                                                     al 0. 95 1. 00                                                   fe 0. 94 0. 99 1. 00                                                 m g –0 .0 9 –0 .1 7 –0 .2 1 1. 00                                               ca –0 .8 4 –0 .8 8 –0 .8 3 0. 09 1. 00                                             n a –0 .5 5 –0 .4 8 –0 .5 0 –0 .0 8 0. 12 1. 00                                           k 0. 94 0. 98 0. 96 –0 .2 4 –0 .9 0 –0 .4 3 1. 00                                         ti 0. 98 0. 99 0. 98 –0 .1 1 –0 .8 6 –0 .5 2 0. 96 1. 00                                       p 0. 07 0. 16 0. 10 0. 02 –0 .3 7 0. 22 0. 17 0. 09 1. 00                                     m n 0. 72 0. 81 0. 80 –0 .3 3 –0 .7 6 –0 .2 4 0. 81 0. 78 0. 38 1. 00                                   cr 0. 75 0. 72 0. 75 –0 .2 2 –0 .5 5 –0 .4 9 0. 73 0. 74 –0 .1 7 0. 52 1. 00                                 lo i –0 .9 5 –0 .9 1 –0 .9 3 0. 07 0. 68 0. 68 –0 .8 6 –0 .9 5 0. 13 –0 .6 6 –0 .7 7 1. 00                               ba 0. 95 0. 98 0. 98 –0 .2 0 –0 .8 8 –0 .4 9 0. 96 0. 98 0. 15 0. 81 0. 72 –0 .9 2 1. 00                             co 0. 88 0. 93 0. 94 –0 .3 3 –0 .8 4 –0 .3 6 0. 91 0. 92 0. 22 0. 84 0. 70 –0 .8 3 0. 94 1. 00                           sr –0 .8 0 –0 .8 3 –0 .7 8 –0 .2 0 0. 93 0. 16 –0 .8 1 –0 .8 3 –0 .3 1 –0 .6 6 –0 .5 0 0. 68 –0 .8 0 –0 .7 4 1. 00                         u 0. 72 0. 72 0. 77 –0 .3 9 –0 .5 1 –0 .4 8 0. 70 0. 73 –0 .2 8 0. 43 0. 76 –0 .7 7 0. 72 0. 70 –0 .4 4 1. 00                       v 0. 82 0. 88 0. 90 –0 .3 2 –0 .7 3 –0 .4 3 0. 84 0. 87 –0 .0 6 0. 67 0. 63 –0 .8 4 0. 90 0. 87 –0 .6 3 0. 83 1. 00                     zr 0. 95 0. 90 0. 90 –0 .0 4 –0 .7 5 –0 .5 8 0. 87 0. 94 –0 .1 2 0. 62 0. 76 –0 .9 7 0. 92 0. 82 –0 .7 4 0. 76 0. 84 1. 00                   to t/ c –0 .9 1 –0 .9 0 –0 .9 1 0. 00 0. 73 0. 49 –0 .8 3 –0 .9 3 0. 02 –0 .6 9 –0 .6 8 0. 94 –0 .8 9 –0 .8 5 0. 76 –0 .6 4 –0 .7 8 –0 .9 2 1. 00                 to t/ s 0. 85 0. 93 0. 95 –0 .4 0 –0 .8 1 –0 .3 2 0. 91 0. 90 0. 10 0. 80 0. 66 –0 .8 2 0. 92 0. 94 –0 .7 1 0. 77 0. 92 0. 81 –0 .8 1 1. 00               m o 0. 48 0. 50 0. 57 –0 .6 0 –0 .2 8 –0 .3 0 0. 49 0. 50 –0 .3 8 0. 27 0. 62 –0 .5 6 0. 50 0. 55 –0 .1 6 0. 90 0. 69 0. 53 –0 .4 3 0. 67 1. 00             cu 0. 18 0. 29 0. 24 0. 39 –0 .3 4 –0 .0 5 0. 20 0. 26 0. 45 0. 32 –0 .0 5 –0 .1 4 0. 26 0. 31 –0 .4 5 –0 .0 9 0. 17 0. 16 –0 .3 0 0. 16 –0 .3 5 1. 00           pb 0. 79 0. 81 0. 76 0. 07 –0 .7 4 –0 .5 7 0. 81 0. 80 0. 16 0. 58 0. 58 –0 .7 4 0. 80 0. 68 –0 .7 1 0. 55 0. 71 0. 75 –0 .6 5 0. 64 0. 25 0. 40 1. 00         zn 0. 74 0. 74 0. 69 –0 .0 5 –0 .6 8 –0 .5 7 0. 78 0. 72 0. 26 0. 57 0. 59 –0 .6 5 0. 73 0. 63 –0 .5 9 0. 50 0. 57 0. 65 –0 .5 3 0. 56 0. 21 0. 30 0. 93 1. 00       n i 0. 90 0. 94 0. 94 –0 .2 9 –0 .7 6 –0 .6 0 0. 94 0. 93 0. 05 0. 75 0. 81 –0 .9 0 0. 94 0. 88 –0 .6 7 0. 79 0. 85 0. 88 –0 .8 1 0. 87 0. 60 0. 14 0. 84 0. 83 1. 00     as 0. 71 0. 69 0. 73 –0 .3 6 –0 .4 6 –0 .6 3 0. 71 0. 70 –0 .0 7 0. 47 0. 73 –0 .7 5 0. 70 0. 68 –0 .3 3 0. 75 0. 69 0. 71 –0 .5 7 0. 68 0. 68 –0 .1 5 0. 63 0. 66 0. 83 1. 00   cd 0. 50 0. 55 0. 49 –0 .1 3 –0 .6 4 –0 .1 4 0. 53 0. 53 0. 37 0. 66 0. 14 –0 .4 1 0. 59 0. 60 –0 .5 5 0. 26 0. 54 0. 47 –0 .4 5 0. 54 0. 06 0. 51 0. 53 0. 50 0. 48 0. 18 1. 00 komar et al.: geochemical characterization and environmental status of makirina bay sediments (northern dalmatia, republic of croatia) geologia croatica 87 the results of pca are reported in fig. 5. the first two principal components (pcs) accounted for 64.22% of the total variance in the dataset. the first component explains 48.02% of the total variance and exhibits one group with negative loadings and one with positive loadings. highly negative loadings reveal an association of major (si, fe, ti, k) and trace elements (ba, co, ni, v, zr) related to al, suggesting their common origin (terrigenous aluminosilicates). another group of trace elements (cr, u, mo, pb, zn, as, cd) also has negative but not high loadings, meaning that those elements are partly associated with terrigenous aluminosilicates and also with other sources. in the first component, ca, sr, mg, loss of ignition (loi), and tc are positively loaded due to their inverse geochemical behaviour with respect to aluminosilicates. loi, tc, ca, and sr represent the autochthonous biogenic fraction of the sediment. mg corresponds with terrigenous carbonates (dolomite), but could also be related to the autochthonous fraction (aragonite and mg calcite). negatively loaded cu and p are probably anthropogenic sources linked to the use of fertilizers and blue vitriol (cuso4x5h2o) in the surroundings of makirina bay. the second pc represents 16.2% of the total variance. cd, pb, and zn have similar positive loadings, highlighting their common origin. as, cr, mo, u, and v show associations with ts. these trace elements are redox-sensitive elements, known to become highly enriched in anoxic sediments (legeleux et al., 1994). 4.3. assessment of sediment pollution for pte (as, cd, cu, pb, mo, ni, zn), ef were calculated (table 4). as natural background values, the concentrations of pte in surface sediments of the central adriatic were used (table 2). calculated ef values for cd, ni, and zn are < 1 and show no enrichment. ef values for as, cu, and pb are < 3, indicate minor enrichment, while ef values for mo indicate minor to moderate enrichment. ef values for as, cu, and pb are higher in the top 5 cm of sediment cores, which could be a result of recent anthropogenic enrichment with the aforementioned pte. enrichment of sediments with as and cu is probably due to anthropogenic activities in the surroundings of the bay, including figure 5: pca diagram result for overall dataset. table 4: calculated ef and tf for selected pte and their concentrations in seagrass c. nodosa. as cd cu pb mo ni zn ef ef ef ef ef ef ef 0–5 cm 1.4 0.7 1.1 2.2 2.4 0.2 0.7 5–10 cm 1.2 0.5 1 2.0 3.1 0.2 0.5 10–15 cm 1.2 0.6 1 1.8 3.1 0.2 0.5 15–20 cm 1.2 0.6 0.9 1.8 3.9 0.2 0.5 20–25 cm 1.2 0.5 0.7 1.7 4.2 0.2 0.5 pte concentration in c. nodosa 1.26 0.13 6.12 1.4 3.1 1.28 17.8 tf range 0.06–0.11 0.36–1.33 0.14–0.32 0.08–0.13 0.09–0.16 0.04–0.07 0.27–0.48 mean tf 0.09 0.58 0.24 0.1 0.12 0.06 0.38 the use of pesticides and fertilizers in agriculture. pb-enrichment is most likely a consequence of runoff from the kapela–tisno road located in the southern part of the bay. mo ef values increase with depth of sediment core. molybdenum is an element that is strongly enriched in highly reducing conditions accompanied by accumulation of organic matter and precipitation of iron sulfide (wedepohl, 1978) and shows the greatest degree of enrichment in reducing sediments relative to crustal values (crusius et al., 1996). 4.4. sequential extraction results in the applied sequential leaching procedure, the labile/residual fractions considered were: water soluble fraction (1), exchangeable fraction (2), oxidizable fraction (3), (easily) reducible fraction (4), and reducible+residual fraction (5). geologia croatica 68/1geologia croatica 88 pte extracted in the first fraction by h2o, are relatively labile and thus may be potentially bioavailable to the surrounding ecosystem. this phase contains the water soluble species made up of free ions and ions complexed with soluble organic matter and other constituents (filgueiras et al., 2002). the next phase was the exchangeable fraction (2), which includes weakly adsorbed pte retained on the solid surface by relatively weak electrostatic interaction, pte that can be released by ion-exchange processes, and pte that can be coprecipitated with carbonates present in many types of sediments. changes in the ionic composition which influence adsorption–desorption reactions or lower the ph could cause remobilization of pte from this fraction (filgueiras et al., 2002). the oxidizable fraction (3) corresponds to trace elements bound to organic matter and sulfides. pte associated with oxidizable phases are assumed to remain in sediments for longer periods, but may be mobilized by decomposition processes. degradation of organic matter under oxidizing conditions can lead to a release of soluble pte bound to this component (filgueiras et al., 2002). the last two fractions, considered in the applied sequential leaching procedure were reducible (4) and reducible + residual fractions (5). the (easily) reducible fraction (4) is linked to amorphous manganese hydroxides, which are thermodynamically unstable under anoxic conditions. the reducible + residual fraction (5) is linked to amorphous fe hydroxides (moderately reducible part). the residual fraction includes naturally occurring crystalline mn hydroxide minerals. pte in this fraction are retained within their crystal lattices, and thus pte bound to this component are regarded as stable and are not susceptible to remobilization under normal environmental conditions (filgueiras et al., 2002, forghani et al., 2009). arsenic (as) is mainly bound to the oxidizable (3) and reducible fraction (4) (fig. 6a). the least mobile was arsenic in the water soluble and exchangeable phase. it has already been reported that in reduced sediments the distribution of arsenic is controlled mainly by sulphides (price & pichler, 2005). arsenic mobility in an anaerobic, sulfur-rich environment is very low and can also be limited by its coprecipitation with secondary sulfide minerals and more generally by clays (reimann & de caritat, 1998, plant et al., 2003). the dominant proportion of cadmium (cd) was found to be associated with the exchangeable fraction (2) (fig. 6b), meaning that most of the cd present in the sediments is exchangeable and bound to carbonates. this observation is in agreement with some other studies (billon et al., 2002, ghrefat & yusuf, 2006, li et al., 2007, gao et al., 2010, liu et al., 2011, zhang et al., 2012, liu et al., 2013). the high content of cd in the exchangeable fraction could result from the high concentration of clin coastal sediments and the formation of soluble cd-cl complexes. this might induce cd desorption from the sediments (liu et al., 2011, li et al., 2007). cd has no essential biological function and is highly toxic to plants and animals (ghrefat & yusuf, 2006). although a high mobility and bioavailability of cd was observed, it could hardly cause a harmful effect on the local environment owing to its low total concentration detected in these sediments. a significant amount of copper (cu) is bound to the oxidizable fraction (3) (fig. 6c). the tendency of cu to be associated with the oxidizable fraction has been reported in several other studies (li et al., 2001, ngiam & lim, 2001, morillo et al., 2004, burton et al., 2005). cu could easily form complexes with organic matter due to the high stability of organic-cu complexes (jones & turki, 1997, li et al., 2001, morillo et al., 2004, burton et al., 2005). cu is essential for all organisms, but can be toxic at high doses (reimann & de caritat, 1998). under reducing conditions, cu has very low mobility (reimann & de caritat, 1998), but it can be released into the environment under oxidizing conditions. the highest content of molybdenum (mo) (fig. 6d) is associated with the water soluble fraction (1). molybdenum is essential for all organisms except some bacteria, but is considered toxic in large amounts, causing secondary cu deficiency (reimann & de caritat, 1998, yu et al., 2011). the water soluble form of mo includes readily soluble molybdates and water soluble organic complexes. the bioavailability of mo to plants is largely dependent on the sediment ph and is greater under neutral and alkaline conditions than under acidic ones (reimann & de caritat, 1998, adriano, 2001).the ready mobility and bioavailability of mo could be related to neutral–alkaline conditions in the makirina bay sediments. the maximum values of nickel (ni) (fig. 6e) were found in the oxidizable (3) fraction. this is in agreement with the results of some other studies (kiratli & ergin, 1996, purushothaman et al., 2012). ni is often bound to organic matter (sakan et al., 2011) due to the adsorption of ni by the formation of ligands in the presence of high organic content (purushothaman et al., 2012). ni is toxic to organisms at elevated levels, but trace amounts of this element are required for several biological processes (adriano, 2001). a large proportion of lead (pb) was mainly bound to the reducible + residual fraction (5) (fig. 6f). similar results were also found in other studies (morillo et al., 2004, li et al., 2007). fe and mn hydrous oxides are important scavengers of pb in sediments (morillo et al., 2004, wang et al., 2010). the proportion of pb in the last fraction (5) was much higher than that of other pte in this fraction. the presence of pb in the exchangeable phase suggest coprecipitation with, or adsorption onto caco3 (kiratli & ergin, 1996). pb is considered a non-essential and toxic element (adriano, 2001). its distribution shows an affinity with the oxidizable and exchangeable fraction, but it is also strongly bound to the reducible + residual fraction (5), which reduces its total mobility. the most abundant fraction for zinc (zn) is the oxidizable fraction (3) (fig. 6g). zinc is a micronutrient and chalkomar et al.: geochemical characterization and environmental status of makirina bay sediments (northern dalmatia, republic of croatia) geologia croatica 89 figure 6: vertical profiles of pte partitioning. a b c d e f g geologia croatica 68/1geologia croatica 90 cophilic in nature. in highly anoxic conditions it is associated with carbonate, sulfides, and organic matter and is not affected by the redox conditions (yu et al., 2001, purushothaman et al., 2012). organic matter, s, and zn are closely related in many anoxic sediments (kiratli & ergin, 1996). in general, the mobility of pte in the makirina bay sediments decreased in the order mo > cd > pb > ni > zn > cu > as. the results of the sequential leaching procedure reveal that, except for cd and mo, pte in makirina bay sediments are not readily mobile or bioavailable since only a small percentage of pte is extracted in the first two steps. the variation of the speciation of the pte with depth could provide information about recent enrichment if the concentrations of pte associated with the more mobile fractions are higher in the upper part of the sediment core (riba et al., 2002, forghani et al., 2009). similarly to ef values (table 4), the sum of concentrations of as, cu, and pb in the first two fractions (fig. 7) decreases with increasing depth of sediment core, reflecting the fact that the aforementioned pte have been mainly added to sediments in recent years. 4.5. transfer factor concentrations of as, cd, cu, mo, ni, pb, and zn in the belowground biomass of c. nodosa, (the most abundant aquatic plant in the bay), are presented in table 4. calculated tf values (table 4) for selected pte were in the descending order cd > zn > cu > ni > mo >as > pb. all tf were less than 1, indicating that c. nodosa did not effectively transfer selected pte from the sediment to the root.the tf results more or less confirmed the sequential extraction procedure results, the only exceptions being cd and mo, probably as a consequence of the generally low total cd concentrations in the makirina bay sediments and high anoxic conditions at the sediment–water interface. mo is predicted to be in the iv oxidation state under anoxic conditions, whereas only the soluble mo(vi) forms are available for plants (zimmer & mendel, 1999). 5. conclusion this paper has examined the basic characteristics (ph, eh, grain size) of the makirina bay sediments, their mineralogical and geochemical composition. the novel contribution of present research is the determination of chemical speciation of several pte (as, cd, cu, mo, ni, pb, zn) in the makirina bay sediments, the determination of the pte content in seagrass (c. nodosa) and their tf calculation. the geochemical composition of the makirina bay sediments is defined by the mineralogical and granulometric composition of the sediments. the results of the ef and sequential leaching procedure indicate an anthropogenic contribution of as, cu, and pb to the sediment due to agricultural activity in the area surrounding the bay (as, cu) and the vicinity of the main road (pb). despite the ready mobility and bioavailability of cd and mo, their transfers from sediment to seagrass roots are not effective. acknowledgement this research was financially supported by the slovenian research agency (arrs) (contract number 1000-11310206) and geoexp, d.o.o., tržič, slovenia. special thanks go to mr boris paškvalin, director of btp, d.d., betina (croatia). references adriano, d.c. (2001): trace elements in terrestrial environments: biogeochemistry, bioavailability, and risks of metals, second edition. springer verlag, new york, 871 p. ahmed, f., hawa bibi, m., seto, k., ishiga, h., fukushima, t. & roser, b.p. (2010): abundances, distribution, and sources of trace metals in nakaumi-honjo coastal lagoon sediments, japan.– environ. monit. assess.,167, 473–491. aitchison, j. (1981): a new approach to null correlations of proportions.– j. int. ass. math. geol., 13, 175–189. aitchison, j. (1986): statistical analysis of compositional data.– chapman & hall, new york, 416 p. ben-yaakov, s. (1973): ph buffering of pore water of recent anoxic marine sediments.– limnol. oceanogr., 18/1, 86–94. blott, s.j. & pye, k. (2001): gradistat: a grain size distribution and statistics package for the analysis of unconsolidated sediments.– earth surf. proc. land., 26, 1237–1248. blott, s.j. & pye, k.(2012): particle size scales and classification of sediment types based on particle size distributions: review and recommended procedures.– sedimentology, 59, 2071–2096. billon, g., ouddane, b., recourt, p. & boughriet, a. (2002): depth variability and some geochemical characteristics of fe, mn, ca, mg, sr, s, p, cd and zn in anoxic sediments from authie bay (northern france).– estuar. coast. shelf s., 55, 167–181. figure 7: the variation of ptes concentrations in the most mobile fraction (f1 and f2) with depth. komar et al.: geochemical characterization and environmental status of makirina bay sediments (northern dalmatia, republic of croatia) geologia croatica 91 birth, g.a. (2003): a scheme for assessing human impacts on coastal aquatic environments using sediments.– in: woodcoffe, c.d.& furness, r.a. (eds.): coastal gis 2003, university of wollongong, australia. burton, e.d., phillips, i.r. & hawker, d.w. (2005): geochemical partitioning of copper, lead and zinc in benthic, estuarine sediment profiles.– j. environ. qual., 34/1, 263–273. chen, c.w., kao, c.m., chen, c.f. & dong, c.d. (2007): distribution and accumulation of heavy metals in the sediments of kaohsiung harbor, taiwan.– chemosphere, 66, 1431–1440. crusius, j., calvert, s., pedersen, t. & sage, d. (1996): rhenium and molybdenum enrichments in sediments as indicators of oxic, suboxic and sulfidic conditions of deposition.– earth planet. sc. lett., 145, 65–78. dean, j.r. (2007): bioavailability, bioaccessibility and mobility of environmental contaminants.– wiley, london, 316 p. dolenec, m., lojen, s., ogrinc, n. & lambaša, ž. (2002): environmentally controlled variations of δ18o and δ13c in mollusc shells from makirina bay, the murter sea and pirovac bay (central adriatic).– rmz-m&g, 49/1, 85–99. dolenec, t., faganeli, j. & pirc, s. (1998): major, minor and trace elements in surficial sediments from the open adriatic sea: a regional geochemical study.– geol. croat., 51/1, 59–73. ebrahimpour, m. & mushrifah, i. (2008): heavy metal concentrations in water and sediments in tasik chini, a freshwater lake, malaysia.– environ. monit. assess., 141, 297–307. filgueiras, a.v., lavilla, i. & bendicho, c. (2002): chemical sequential extraction for metal partitioning in environmental solid samples.– j. environ. monitor., 4, 823–857. forghani, g., moore, f., lee, s. & qishlaqi, a. (2009): geochemistry and speciation of metals in sediments of the maharlu saline lake.– environ. earth sci., 59, 173–184. gao, x., chen, c.a., wang, g., xue, q., tang, c. & chen, s. (2010): environmental status of daya bay surface sediments inferred from a sequential extraction technique.– estuar. coast. shelf s., 86, 369–378. ghrefat, h. & yusuf, n. (2006): assessing mn, fe, cu, zn, and cd pollution in bottom sediments of wadi al-arab dam, jordan.– chemosphere, 65, 2114–2121. ghrefat, h.a., abu-rukah, y. & rosen, m.a. (2011): application of geoaccumulation index and enrichment factor for assessing metal contamination in the sediments of kafrain dam, jordan.– environ. monit. assess., 178, 95–109. jones, b. & turki, a. (1997): distribution and speciation of heavy metals in surficial sediments from the tees estuary, north-east england.– mar. pollut. bull., 34/10, 768–779. kalfakakou, v. & akrida-demertzi, k. (2000): transfer factors of heavy metals in aquatic organisms of different trophic levels.– html publication, 1, url: http://biopolitics.gr/biowp/wpcontent/uploads/2013/04/kalfakakou.pdf (8.10.2013), 768–786. kiratli, n. & ergin, m. (1996): partitioning of heavy metals in surface black sea sediments.– appl. geochem., 11, 775–788. legeleux, f., reyss, j.l., bonte, p. & organo, c. (1994): concomitant enrichments of uranium, molybdenum and arsenic in suboxic continental margin sediments.– oceanol. acta, 17/4, 417–429. li, q., wu, z., chu, b., zhang, n., cai, s. & fang, j. (2007): heavy metals in coastal wetland sediments of the pearl river estuary, china.– environ. pollut., 149, 158–164. li, x., shen, z., wai, o.w.h. & li, y. (2000): chemical partitioning of heavy metal contaminants in sediments of the pearl river estuary.– chem. spec. bioavailab., 12/1, 17–25. li, x., shen, z., wai, o.w.h. & li, y. (2001): chemical forms of pb, zn and cu in the sediment profiles of the pearl river estuary.– mar. pollut. bull., 42/3, 215–232. liu, b., hu, k., jiang, z., yang, j., luo, x. & liu, a. (2011): distribution and enrichment of heavy metals in a sediment core from the pearl river estuary.– environ. earth sci., 62, 265–275. liu, h.c., you, c.f., huang, b.j. & huh, c.a. (2013): distribution and accumulation of heavy metals in carbonate and reducible fractions of marine sediment from offshore mid-western taiwan.– mar. pollut. bull., 73, 37–46. lojen, s., ogrinc, n., dolenec, t., vokal, b., szaran, j., mihelčić, g. & branica, m. (2004): nutrient fluxes and sulfur cycling in the organic-rich sediment of makirina bay (central dalmatia, croatia).– sci. total environ., 327, 265–284. miko, s., koch, g., mesić, s., šparica-miko, m., šparica, m., vreča, p. & dolenec, t. (2007): influence of land use in small karst watersheds on the chemical status of peloid sediments on the eastern adriatic coast.– j. soil. sediment., 7/5, 303–312. miko, s., koch, g., mesič, s., šparica-miko, m., šparica, m., čepelak, r., bačani, a., vreča, p., dolenec, t. & bergant, s. (2008): anthropogenic influence on trace element geochemistry of healing mud (peloid) from makirina cove (croatia).– environ. geol., 55, 517–537. monteiro, f.f., cordeiro, r.c., santelli, r.e., machado, w., evangelista, h., villar, l.s., viana, l.c.a. & bidone, e.d. (2012): sedimentary geochemical record of historical anthropogenic activities affecting guanabara bay (brazil) environmental quality.– environ. earth sci., 65, 1661–1669. morillo, j., usero, j. & gracia, i. (2004): heavy metal distribution in marine sediments from the southwest coast of spain.– chemosphere, 55, 431–442. ngiam, l.s. & lim, p.e. (2001): speciation patterns of heavy metals in tropical estuarine anoxic and oxidized sediments by different sequential extraction schemes.– sci. total environ., 275, 53–61. öztürk, m., özözen, g., minareci, o. & minareci, e. (2009): determination of heavy metals in fish, water and sediments of avsar dam lake in turkey, iran.– j. environ. health sci. eng., 6/2, 73–80. pereira majer, a., varella petti, m.a., navajas corbisier, t., portella ribeiro, a., sawamura theophilo, c.y., alves de lima ferreira, p. & lopes figueira, r.c. (2014): bioaccumulation of potentially toxic trace elements in benthic organisms of admiralty bay (king george island, antarctica).– mar. pollut. bull., 79, 321–325. price, r.e. & pichler, t. (2005): distribution, speciation and bioavailability of arsenic in a shallow-water submarine hydrothermal system, tutum bay, ambitle island, png.– chem. geol., 224, 122–135. plant, j.a., kinniburgh, d.g., smedley, p.l., fordyce, f.m. & klinck, b.a. (2003): arsenic and selenium.– in: sherwood lollar, b., holland, h.d. & turekian, k.k. (eds.): environmental geochemistry, elsevier ltd., amsterdam, 17–65. purushothaman, p., mishra, s., das, a. & chakrapani, g.j. (2012): sediment and hydro biogeochemistry of lake nainital, kumaun himalaya, india.– environ. earth sci., 65, 775–788. qui, y.w., yu, k.f., zhang, g. & wang, w.x. (2011): accumulation and partitioning of seven trace metals in mangroves and sediment cores from three estuarine wetlands of hainan island, china.– j. hazard. mater., 190, 631–638. rao, c.r.m., sahuquillo, a. & lopez sanches, j.f. (2008): a review of the different methods applied in environmental geochemistry for single and sequential extraction of trace elements in soil and related materials.– water air soil poll., 189, 291–333. geologia croatica 68/1geologia croatica 92 reimann, c. & de caritat, p. (1998): chemical elements in the environment, factsheets for the geochemist and environmental scientist.– springer verlag, berlin, 398 p. riba, i., delvalls, t.a., forja, j.m. & gómez-parra, a. (2002): influence of the aznalcóllar mining spill on the vertical distribution of heavy metals in sediments from the guadalquivir estuary (sw spain).– mar. pollut. bull., 44, 39–47. sahuquillo, a., rigol, a. & rauret, g. (2003): overview of the use of leaching/extraction tests for risk assessment of trace metals in contaminated soils and sediments.– trend. anal. chem., 22/3, 152–159. sakan, s.m., đorđević, d.s. & trifunović, s.s. (2011): geochemical and statistical methods in the evaluation of trace elements contamination: an application on canal sediments.– pol. j. environ. stud., 20/1, 187–199. satpathy, k.k., mohanty, a.k., prasad, m.v.r, natesan, u. & sarkar, s.k. (2012): studies on the variations of heavy metals in the marine sediments off kalpakkam, east coast of india.– environ. earth sci., 65, 89–101. šparica, m., crnko, j. & belak, m. (1989): peloid uvale makirina (pirovački zaljev) – elaborat, br. 28/89. institut za geološka istraživanja, oour za geologiju, zagreb. šparica, m., koch, g., belak, m., miko, s., šparica-miko, m., viličić, d., dolenec, t., bergant, s., lojen, s., vreča, p., dolenec, m., ogrinc, n. & ibrahimpašić, h. (2005): recent sediments of makirina cove (northern dalmatia, croatia): their origin viewed through a multidisciplinary approach.– geol. croat., 58/1, 21–72. tessier, a., campbell, p.g.c. & bisson, m. (1979): sequential extraction procedure for the speciation of particulate trace metals.– anal. chem., 51/7, 844–851. varol, m. (2011): assessment of heavy metal contamination in sediments of the tigris river (turkey) using pollution indices and multivariate statistical techniques.– j. hazard. mater., 195, 355–364. verbovšek, t. (2011): a comparison of parameters below the limit of detection in geochemical analyses by substitution methods.– rmz-m&g, 58/4, 393–404. vreča, p. & dolenec, t. (2005): geochemical estimation of copper contamination in the healing mud from makirina bay, central adriatic.– environ. int., 31, 53–61. vreča, p., dolenec, t., šparica, m., pandža, m., lojen, s. & ogrinc, n. (1998): origin of sedimentary organic matter in the surficial sediment of the bay of makirina.– rmz-m&g, 45/1-2, 202–206. vreča, p. (1998): izotopske in geokemične značilnosti recentnega sedimenta iz zaliva makirina, otok murter (srednji jadran) [isotopic and geochemical characteristics of the recent sediment of makirina bay (central adriatic) – in slovenian with an english abstract].– unpubl. msc thesis. university of ljubljana, faculty of natural sciences and engineering, department of geology, ljubljana, 84 p. wang, s., jia, y., wang, s., wang, x., wang, h., zhao, z. & liu, b. (2010): fractionation of heavy metals in shallow marine sediments from jinzhou bay, china.– j. environ. sci., 22/1, 23–31. wedepohl, k.h. (1978): handbook of geochemistry: elements si (14) to v (23), vol. ii/2. springer, berlin. yan, c., li, q., zhang, x. & li, g. (2010): mobility and ecological risk assessment of heavy metals in surface sediments of xiamen bay and its adjacent areas, china.– environ. earth sci., 60, 1469–1479. yu, c., xu, s., gang, m., zhou, l. & chen, g. (2011): molybdenum pollution and speciation in nver river sediments impacted with mo mining activities in western liaoning, northeast china. – int. j. environ. res, 5/1, 205–212. yu, k.c., tsai, l.j., chen, s.h. & ho, s.t. (2001): chemical binding of heavy metals in anoxic river sediments.– water res., 35/17, 4086–4094. yuan, c., shi, j., he, b., liu, j., liang, l. & jiang, g. (2004): speciation of heavy metals in marine sediments from the east china sea by icp-ms with sequential extraction.– environ. int., 30, 769–783. zhang, j. & liu, c.l. (2002): riverine composition and estuarine geochemistry of particulate metals in china – weathering features, anthropogenic impact and chemical fluxes.– estuar. coast. shelf s., 54, 1051–1070. zhang, w., liu, x., cheng, h., zeng, e.y. & hu, y. (2012): heavy metal pollution in sediments of a typical mariculture zone in south china.– mar. pollut. bull., 64, 712–720. zimmer, w. & mendel, r. (1999):molybdenum metabolism in plants.– plant biol., 1, 160–168. žvab rožič, p., dolenec, t., baždarić, b., karamarko, v., kniewald, g. & dolenec, m. (2012): major, minor and trace element content derived from aquacultural activity of marine sediments (central adriatic, croatia).– environ. sci. pollut. r., 19, 2708–2721. manuscript received october 12, 2014 revised manuscript accepted january12, 2015 available online february 27, 2015 2019 | 72/2 | 129–135 | 10 figs. | 2 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction earthquake induced liquefaction is the phenomenon in which loose saturated granular soil loses shear strength due to pore pres­ sure increase, to the point where it is unable to support structures and to remain stable. its devastating effects came to the attention of geotechnical engineers in 1964 when the good friday earth­ quake (magnitude, m = 9.2) in alaska was followed by the ni­ igata earthquake (m = 7.5) in japan (kramer, 1996). the phe­ nomenon of liquefaction (including sand volcanoes) was observed also in close surroundings of the krško-brežice field, in compa­ rable geological conditions, during the zagreb earthquake of 1880, in the villages located in the valley of the sava river, and during the kupa valley earthquake of 1909 (veinović et al., 2007, herak et al., 2009; herak & herak, 2010). re­ cently, the liquefaction in christchurch, new zealand (2011) and in indonesia (2018) reminded other professionals and scientists of its devastating effects. until the haicheng (1975) and tangshan (1976) earth­ quakes it was believed that only clean sands were prone to lique­ faction (shengcong & tatsuoka, 1984). recent investi­ gations have highlighted that earthquakes can trigger shear strength loss in a broad range of types of saturated soils, from sand to low plasticity clays (bray et al., 2004, chu et al., 2004, boulanger & idriss, 2006), although earthquake­induced ground failure is observed less frequently in clays than in sands. cubrinovski et al. (2018) reported liquefaction in well­ graded gravel with at least 30% of sands and silts during the kaikoura (new zealand) earthquake (2016). factors governing liquefaction may be grouped into a geo­ logical profile, consisting of seismicity at the location (e.g. peak liquefaction potential of sands at the krško-brežice field, slovenia jasna smolar*, matej maček and ana petkovšek university of ljubljana, faculty of civil and geodetic engineering, jamova cesta 2, 1000 ljubljana, slovenia; (*corresponding author: jasna.smolar@fgg.uni-lj.si*; matej.macek@fgg.uni-lj.si; ana.petkovsek@fgg.uni-lj.si) doi: 10.4154/gc.2019.12 abstract the krško-brežice field is one of the most seismically active areas in slovenia. the most damaging recorded earthquake with an intensity of viii (ems) occurred on 29th january 1917. it caused damage and claimed two lives. in the last 100 years, 9 earthquakes with intensity higher than vi (ems) have been recorded. at the investigated area, a top layer up to 5 m thick, consisting of recent deposit of very loose silts and sands (ml, sm, sp), covers the medium dense to dense quaternary gravel, beneath which there are over-consolidated, uncemented miocene silts and marls. the top layer could be prone to liquefaction, as reported for the close surroundings of brežice, where the liquefaction phenomenon was observed during the zagreb earthquake in 1880 and during the kupa valley earthquake in 1909. the paper presents the results of laboratory index tests, cyclic simple shear tests and field investigations (spt, cpt, (s)dmt, vs measurements), which were carried out to assess the liquefaction potential of the top layer at the location of the brežice hydroelectric power plant (hpp). all results show that the top layer is prone to liquefaction for an earthquake with a 475 year return period. cyclic simple shear test results show that the liquefaction potential of horizontal ground for an earthquake with a 475 year return period can be reduced by the densification of the top layer to at least 95% of maximum proctor density. ground acceleration, amax, magnitude, m) and soil properties (e.g. liquid limit, wl, plasticity index, ip, density, r, grain size distribution, number of cycles to liquefaction, n, cyclic resistance ratio, crr). the liquefaction potential of soils can be assessed from different laboratory and field investigations by several liq­ uefaction susceptibility criteria, mostly developed for sands (po­ lito & martin, 2001, youd et al., 2001, andrus et al., 2004, boulanger & idriss, 2016, 2006, idriss & bou­ langer, 2006, marchetti & marchetti, 2016, among others). this paper presents the assessment of liquefaction potential of the top layer at the location of the brežice hpp, based on labo­ ratory index and cyclic simple shear tests, as well as field cone penetration tests (cpt/cptu), standard penetration tests (spt), flat (seismic) dilatometer tests ((s)dmt) and shear wave velocity measurements (vs). 2. study area 2.1. geological and hydrological setting the top layer at the location (fig. 1) is up to 5 m thick and con­ sists of loose alluvial silty sands and contains fine coal particles that originate from the flotation processes from the area around 60 km upstream, where the coal mines have operated for the last 300 years. poplar tree roots appear up to 4 m depth and prove the development of the “palaeo” ground during large flood events (petkovšek et al., 2017). beneath the top layer, the medium dense to dense quater­ nary gravels classified as silty sandy gravel (gm) to poorly graded gravel (gp) are deposited in thicknesses of between article history: manuscript received december 02, 2018 revised manuscript accepted march 07, 2019 available online may 31, 2019 keywords: earthquake, csr, liquefaction potential, silty sand, laboratory investigations, field tests g eo lo gi a c ro at ic a geologia croatica 72/2130 8 and 12 m. the bedrock consists of over­consolidated, unce­ mented miocene silt and marl, with some inclusions of weak, soft limestone. the ground water level ranges from 4 ­ 6 m below the ground surface and follows the water level fluctuation in the sava river, which frequently floods the area. during floods, the water level figure 1. location of the brežice hpp – the investigated area in the chain of the lower sava river hydroelectric power plants and the krško nuclear power plant (npp). different colours represent design ground accelerations in rock or firm soil (arso, 2001). figure 2. epicentres of earthquakes at the krško-brežice field and in its close surroundings from 567 to 2007 ad, and the locations where liquefaction-related effects were observed during the zagreb (blue dots) and kupa valley (yellow dots) earthquakes (veinović et al., 2007, herak et al., 2009, herak & herak, 2010). g eologia c roatica smolar et al.: liquefaction potential of sands at the krško-brežice field, slovenia 131 rises above the ground surface and may remain for days (petkovšek et al., 2017). inside the influential area of the brežice hpp, the groundwater regime has been changed due to the operation of the hpp brežice. 2.2. seismicity figure 2 shows the epicentres and magnitudes of earthquakes at the krško-brežice field and in its close surroundings from 567 to 2007 ad. blue and yellow symbols represent locations in croatia where liquefaction was observed during the zagreb (1880) and kupa valley (1909) earthquakes (after veinović et al., 2007 and herak & herak, 2010). the design ground acceleration at the location (table 1) was predicted based on three different methodologies: (1) currently valid slovenian national probabilistic seismic hazard analysis (fig. 1) (arso, 2001), (2) detailed probabilistic seismic hazard analysis at the location of the hpp brežice (aleksovski et al., 2008) and (3) recent seismic hazard harmonization in europe ­ share model (lai et al., 2017). 2.3. earthquake induced cyclic stress ratio (csr) csr can be estimated using eq. 1, developed as part of the sim­ plified liquefaction procedure (boulanger & idriss, 2014): (1) where amax is the peak ground surface acceleration, g the accele­ ration of gravity, sv the total vertical stress at depth z, sv′ the ef­ fective vertical stress at depth z and rd shear stress reduction fac­ tor that accounts for the dynamic response of the soil profile. based on idriss (1999), parameter rd could be calculated using eq. 2. (2) (3) (4) where z (m) is the depth below the ground surface, m moment magnitude and the arguments inside the sin terms are in radians. the case history csr values adjusted to a reference magni­ tude m = 7.5 and sv′ = 1 atm = 101 kpa could be calculated using eq. 5 and eq. 6 (boulanger & idriss, 2014). (5) (6) where ks ≈ 1. csrm=7.5,sv=1 varies with depth. in this study it is evaluated for depths between 0.5 m and 4.0 m, for an earthquake with a 475 year return period, design ground acceleration of 0.350 g (table 1, loose silt, sand) and gw level of 0.1 m. using parameters listed above, csrm=7.5,sv′=1 is between 0.30 and 0.35. 3. experimental methods preliminary assessment of the top layer liquefaction potential was carried out based on its grain size distribution (sist­ts cen table 1. design ground accelerations at the location of the brežice hpp. method return period magnitude design ground acceleration rock or firm soil loose silt, sand slovenian national probabilistic seismic hazard analysis (arso, 2001) 475 0.225 g 1000 0.250 g detailed probabilistic seismic hazard analysis (aleksovski et al., 2008) 200 5.6 0.230 g 0.290 g 475 5.8 0.280 g 0.350 g 1000 6.25 0.295 g 0.370 g share model (lai et al., 2017) 475 0.320 g figure 3. cyclic simple shear apparatus (left) and schematic illustration of the investigation (right). g eo lo gi a c ro at ic a geologia croatica 72/2132 iso/ts 17892­4) and atterberg limits (sist­ts cen iso/ts 17892­12). the laboratory cyclic simple shear apparatus (fig. 3, left), de­ veloped by seiken inc., was used to study the liquefaction poten­ tial of the top layer at natural void ratio and to evaluate the densi­ fication impact on the liquefaction potential mitigation. a procedure similar to that described by das (1992) was used. tests were performed on top layer specimens statically compacted at their optimal water content into a mould with a diameter of 70 mm and height of 30 mm to the desired density (void ratio), and on in­ tact specimens from top layer. the specimens were sheathed in a protective latex membrane without reinforcement. saturation was achieved by using the co2, water, and axis translation technique. the saturation was successfully completed when the skempton parameter b was higher than 0.95. after satu­ ration, the specimens were isotropically consolidated at 75 kpa of effective stress. the specimens were loaded with horizontal sinusoidal load at 0.5 hz at desired cyclic stress ratio in undrained conditions (fig. 3, right). the beginning of liquefaction was de­ fined when the increase of pore water pressure was equal to 95% of effective vertical stress before cyclic loading. liquefaction potential of the top layer was evaluated also based on the results of in­situ standard penetration tests (spt) (sist en iso 22476­3), cone penetration tests (cpt/cptu) (sist en iso 22476­1), flat dilatometer tests (dmt) (sist­ts cen iso/ts 22476­11) and shear wave velocity measurements (vs). spt and cpt are generally preferred for the evaluation of liquefaction potential because of the more extensive database and experience (youd et al., 2001). while the preferred spt and cpt are recommended only for non­gravel soils, vs measure­ ments are appropriate for all soil types (andrus et al., 2004). 4. results and discussion 4.1. index properties – preliminary assessment of liquefaction potential table 2 presents the index geotechnical properties of representa­ tive top layer specimens, and fig. 4 (grey curves) shows the grain size distribution curves of all the investigated specimens. the grain size distribution of the top layer is not uniform and may vary from sandy silt to poorly graded sand. after ishihara et al. (1980), the top layer belongs to the group of potentially liq­ uefiable to most liquefiable soils. in comparison with the inves­ tigated samples, poorly graded sands from nova loza and moj dvor, where liquefaction appeared in 1880, belong to the group of most liquefiable soils (veinović et al., 2007). the toyoura table 2. index properties of three samples from the top layer (adapted after petkovšek et al., 2017). parameter test method sample 1 sample 2 sample 3 uscs classification astm d2487-10 ml/cl sc sm natural water content, w0 (%) sist-ts cen iso/ts 17892-1 5.06 16.3 21.5 natural density, r (t/m3) sist-ts cen iso/ts 17892-2 1.30 1.28 1.23 dry density, rd (t/m3) sist-ts cen iso/ts 17892-2 1.23 1.10 1.01 void ratio, natural state, e0 (-) – 1.15 1.53 1.61 particle density, rs (t/m3) sist-ts cen iso/ts 17892-3 2.64 2.78 2.64 fines content, < 0.063 mm (%) sist-ts cen iso/ts 17892-4 54 38 19 liquid limit, wl (%) sist-ts cen iso/ts 17892-12 30 24–26 39 plasticity index, ip (%) sist-ts cen iso/ts 17892-12 9 6–7 – optimum water content, spct*, wopt (%) din 18127 17.4 15.0 27.5 maximum dry density, spct*, rdmax (t/m3) din 18127 1.65 1.77 1.34 *spct – standard proctor compaction test figure 4. grain size distribution of the top layer from the test site (grey curves). grain size distribution curves for toyoura sand, nova loza and moj dvor are reproduced from hosono & yoshimine (2004) and veinović et al. (2007), while boundaries for potentially liquefiable and most liquefiable soils are reproduced from ishihara et al. (1980). g eologia c roatica smolar et al.: liquefaction potential of sands at the krško-brežice field, slovenia 133 sand also belongs to the same group, and was in the past widely used as reference material for the study of liquefaction. using plasticity liquefaction criteria proposed by polito (2001), the top layer also belongs to the group of potentially liquefiable to liquefiable soils (fig. 5). 4.2. laboratory cyclic simple shear tests figure 6 shows the results of cyclic simple shear tests as a link between the induced cyclic stress ratio (csr) and measured num­ ber of cycles to liquefaction. the tests were carried out on intact specimens and specimens prepared at different degrees of com­ paction (dpr), expressed as the ratio between achieved dry density and maximum spct dry density given in table 2. csrm=7.5,sv′=1 at the investigated area is about 0.30 (fig. 6, horizontal solid grey line), while the corresponding equivalent number of stress cycles to liquefaction (n), determined after kramer (1996), for an earthquake with a magnitude of 7.5 is about 15 (fig. 6, vertical solid grey line). results of the laboratory cyclic simple shear tests confirm that the intact top layer is prone to liquefaction for an earthquake with a 475 year return period. results obtained on intact top layer specimens are comparable with those for the toyoura sand (ho­ sono & yoshimine, 2004). mechanically improved speci­ mens compacted to at least 95% of maximum proctor dry density (table 2) will very probably resist the 475 year return period earthquake, although high excess pore pressure would be gene­ rated. these findings are valid for the horizontal ground without surface loading and with the gw level at the foundation ground (e.g. 0.1 m below ground surface). 4.3. standard penetration tests (spt) figure 7 (red symbols) shows (n1)60 values calculated from spt measurements in the top layer at the location of the brežice hpp, in comparison with spt based liquefaction case history data, including soils with different contents of fines (idriss & boulanger, 2010). recommended deterministic spt based triggering correlations (boundary curves) for cohesionless soils having various amounts of fines (fc), presented in fig. 7, are summarized after idriss & boulanger (2006). results of spt confirm that the top layer is prone to lique­ faction for an earthquake with a 475 year return period. 4.4. cone penetration tests (cpt/cptu) figure 8 shows the qc1n values calculated from cpt measure­ ments in the top layer at the location of the brežice hpp in com­ parison with cpt based liquefaction case history data, including soils with different contents of fines (boulanger & idriss, 2014). recommended deterministic cpt based triggering corre­ lations (boundary curves) for clean sands and for cohesionless soils with various amounts of fines (fc) presented in fig. 8 are summarized after boulanger & idriss (2014). results of cpt also confirm that the top layer is prone to liquefaction for an earthquake with a 475 year return period. 4.5. flat dilatometer tests (dmt) figure 5. assessment of the liquefaction potential based on plasticity liquefaction criteria proposed by polito (2001). figure 6. results of cyclic simple shear tests. data for the toyoura sand were summarized after hosono & yoshimine (2004). key: s1, s2, s3 – sample 1, sample 2 and sample 3, e_i – initial void ratio (at preparation of the specimen), e_s – void ratio prior to cyclic loading (after consolidation), d_pr;s – the ratio between specimens’ dry density prior to cyclic loading and maximum spct dry density, red curve – assessed boundary between conditions where liquefaction is expected (below curve) and where resistant to liquefaction is sufficient (above curve). figure 7. spt – based soil liquefaction potential assessment with the case history data and recommended boundary curves for soils with different fines contents (fc). (n1)60 – corrected spt n value for 60% energy efficiency and overburden pressure of 1 atm. figure 8. cpt – based soil liquefaction potential assessment with the case history data and recommended boundary curves for soils with different fines content (fc). qc1n – normalized cone tip resistance. g eo lo gi a c ro at ic a geologia croatica 72/2134 figure 9 shows the kd measured values using dmt in the top layer at the location of the hpp brežice in comparison with dmt-kd based liquefaction case history data for silty sand and sandy silt, regardless of the fines content (marchetti & marchetti, 2016, rollins & remund, 2016). recommended determin­ istic dmt based triggering correlation (boundary curve) for clean sand presented in fig. 9 is summarized after robertson (2012). results of dmt also show that the top layer is prone to liq­ uefaction for an earthquake with a 475 year return period. 4.6. shear wave velocity measurements (vs) figure 10 shows the vs1 values calculated from shear wave veloc­ ity measurements in the top layer at the location of the brežice hpp in comparison with liquefaction resistance curves proposed by andrus & stokoe (2000) and case history data (an­ drus et al., 2004). shear wave velocity measurements also confirm that the top layer is prone to liquefaction for an earthquake with a 475 year return period. 5. conclusions the liquefaction potential of the top layer at the krško-brežice field was assessed using laboratory and field tests. results were compared with case history data and recommended boundary liquefaction curves and were evaluated using liquefaction sus­ ceptibility criteria proposed by different authors. it was observed that there are no significant differences in the evaluation of liquefaction potential based on the various test methods. the analyses indicate that there is a clear threat of liqu­ efaction in the top layer, assuming a water table 0.1 m below the ground surface for an earthquake with a 475 year return period. thus, for liquefaction potential mitigation, the sites require ground improvement (densification). the efficiency of in-situ mechanical improvement for the liquefaction potential mitigation of the top layer was investigated in the scope of the design of the brežice hpp, using three different techniques: vibratory roller compaction, rapid impact compac­ tion (ric) and soil mixing. the efficiency of each technique was analysed in petkovšek et al. (2017) and vukadin (2013). acknowledgement this work was funded by the hess and european union’s hori­ zon 2020 research and innovation programme under grant agree­ ment no. 700748 and realised in close cooperation with irgo ljubljana and slp ljubljana. the authors would like to express special thanks to mr. b.sc. andrej unetič (hse invest) for his help at realising the investigation program and to many engineers and technicians for their vital field work and data collection. references aleksovski, d., mirakovski, g., dojčinovski, d., šešov, v., edip, k., zafirova i., gadja, v. & gjorgjeska, i. (2008): he brežice geofizikalne raziskave in seizmična mikrorajonizacija.– iziis univerze sv. kiril i metodij, skopje. andrus, r.d. & stokoe, k.h. (2000): liquefaction resistance of soils from shear-wave velocity.– journal of geotechnical and geoenvironmental engineer­ ing, 126, 1015–1025. doi: 10.1061/(asce)1090-0241(2000)126:11(1015) andrus, r.d., stokoe, k.h. & hsein juang, c. (2004): guide for shearwave-based liquefaction potential evaluation. earthq.– spectra 20, 285–308. doi: 10.1193/1.1715106 arso (2001): slovenian environment agency. http://www.arso.gov.si/potresi/podatki/ projektni _pospesek_ tal.html (accessed: 29.11.2018). astm d2487-10 (2010): standard practice for classification of soils for engineering purposes (unified soil classification system).– astm international, west con­ shohocken, pa, 2010. boulanger, r. & idriss, i. (2014): cpt and spt based liquefaction triggering procedures.– rep no ucdcgm-14 1. boulanger, r.w. & idriss, i.m. (2016): cpt-based liquefaction triggering procedure.– j. geotech. geoenvironmental eng., 142. doi: 10.1061/(asce) gt.1943­5606.0001388 boulanger, r.w. & idriss, i.m. (2006): liquefaction susceptibility criteria for silts and clays.– j. geotech. geoenvironmental eng., 132, 1413–1426. doi: 10.1061/(asce)1090-0241(2006)132:11(1413) bray, j.d., sancio, r.b., durgunoglu, t., onalp, a., youd, t.l., stew­ art, j.p., seed, r.b., cetin, o.k., bol, e., baturay, m.b., chris­ tensen, c. & karadayilar, t. (2004): subsurface characterization at ground failure sites in adapazari, turkey.– j. geotech. geoenvironmental eng., 130, 673–685. doi: 10.1061/(asce)1090-0241(2004)130:7(673) chu, d.b., stewart, j.p., lee, s., tsai, j.s., lin, p.s., chu, b.l., seed, r.b., hsu, s.c., yu, m.s. & wang, m.c.h. (2004): documentation of soil condi­ tions at liquefaction and non-liquefaction sites from 1999 chi–chi (taiwan) earth­ quake.– soil dyn. earthq. eng., 24, 647–657. doi: 10.1016/j.soildyn.2004.06.005 cubrinovski, m., rhodes, a., de la torre, c., bray, j. & ntritsos, n. (2018): liquefaction hazards from “inherited vulnerabilities.”– ce/papers 2, 39–54. doi: 10.1002/cepa.661 das, b.m. (1992): principles of soil dynamics, 1st edition.– thomson-engineering. din 18127 (2012): soil, investigation and testing proctor-test. herak, d., herak, m. & tomljenović, b. (2009): seismicity and earthquake focal mechanisms in north-western croatia.– tectonophysics, 465, 212–220. doi: 10.1016/j.tecto.2008.12.005 herak, d. & herak, m. (2010) the kupa valley (croatia) earthquake of 8 october 1909–100 years later.– seismol. res. lett., 81, 30. doi: 10.1785/gssrl.81.1.30 hosono, y. & yoshimine, m. (2004): liquefaction of sand in simple shear con­ dition. in proceedings of the international conference on cyclic behaviour of soils and liquefaction phenomena, bochum, germany, 31 march – 02 april 2004. a.a. balkema, rotterdam: 129–136 doi: 10.1201/9781439833452.ch16 figure 9. dmt – based soil liquefaction potential assessment with the case history data and recommended boundary curve for clean sand. kd horizontal stress index. figure 10. liquefaction resistance curves proposed by andrus & stokoe (2000) with case history data and calculated values for the top layer at the location of the hpp brežice. vs1 stress-corrected shear-wave velocity. g eologia c roatica smolar et al.: liquefaction potential of sands at the krško-brežice field, slovenia 135 idriss, i.m. (1999): an update to the seed-idriss simplified procedure for evaluating liquefaction potential, in proceedings, trb workshop on new approaches to liqu­ efaction, publication no. fhward­99­165, federal highway administration. idriss, i.m. & boulanger, r.w. (2006): semi-empirical procedures for evaluating liquefaction potential during earthquakes.– soil dyn. earthq. eng., 26, 115–130. doi: 10.1016/j.soildyn.2004.11.023 idriss, i.m. & boulanger, r.w. (2010): spt based liquefaction triggering pro­ cedures. report no. ucd/cgm­10­02. center for geotechnical modeling, de­ partment of civil and environmental engineering, university of california. davis, california. ishihara, k., troncoso, j., kawase, y. & takahashi, y. (1980): cyclic strength characteristics of tailings materials.– soils and foundations, 20/4, 127–142. doi: 10.3208/sandf1972.20.4_127 kramer, s.l. (1996): geotechnical earthquake engineering. prentice hall. lai, c.g., meisina, c., cosentini r. m., bozzoni, f., persichillo, p., bordoni, m., tumiati, m., viana da fonseca, a., ferreira, c., ramos, c., petkovšek, a., smolar, j., oblak, a., maček, m., kosič, m., kuder, s., petrovič, d., dolšek, m., lesjak, m., zakonjšek, d., lesjak, i., strniša, g., padovan, b., logar, j., ozcep, f., oztoprak, s., bozbey, i., aysal, n., oser, c., sargin, s., tezel, o., cinku, m. & ozdemir, k. (2017): report on ground characterization of the four areas selected as testing sites by using novel technique and advances metodologies to perform in situ and laboratory tests. deliverable d2.1. v 1.0. project liquefact, h2020­dra­2015, ga no. 700748. marchetti, d. & marchetti, s. (2016): flat dilatometer (dmt). some recent advances.– procedia eng., 158, 428–433. doi: 10.1016/j.proeng.2016.08.467 petkovšek, a., maček, m. & smolar, j. (2017): testing methods for me­ chanically improved soils: reliability and validity.– acta polytech. ctu proc. 10, 16–33. doi: 10.14311/app.2017.10.0016 polito, c.p. & martin, j.r. (2001): effects of nonplastic fines on the liquefac­ tion resistance of sands.– j. geotech. geoenvironmental eng., 127, 408–415. doi: 10.1061/(asce)1090-0241(2001)127:5(408) robertson, p.k. (2012): interpretation of in-situ tests – some insights.– in: proc. 4 int. conf. on site characterization. presented at the isc’4, brazil. rollins, k.m. & remund, t.k. (2016): evaluation of dmt liquefaction trigger­ ing curves based on field case histories.– in: geotechnical and geophysical site characterization 5. sydney. shengcong, f. & tatsuoka, f. (1984): soil liquefaction during haicheng and tangshan earthquake in china.– a review. soils found. 24, 11–29. doi: 10.3208/ sandf1972.24.4_11. sist en iso 22476-3 (2005): geotechnical investigation and testing field testing part 3: standard penetration test (iso 22476-3:2005). sist en iso 22476-1 (2013): geotechnical investigation and testing field testing part 1: electrical cone and piezocone penetration test (iso 22476-1:2012). sist-ts cen iso/ts 17892-1 (2004): geotechnical investigation and testing labora­ tory testing of soil part 1: determination of water content (iso 17892-1:2014). sist-ts cen iso/ts 17892-2 (2004): geotechnical investigation and testing labora­ tory testing of soil part 2: determination of bulk density (iso/ts 17892-2:2004). sist-ts cen iso/ts 17892-3 (2004): geotechnical investigation and testing labora­ tory testing of soil part 3: determination of particle density pycnometer me thod (iso/ts 17892-3:2004). sist-ts cen iso/ts 17892-4 (2004): geotechnical investigation and testing labora­ tory testing of soil part 4: determination of particle size distribution (iso/ts 17892-4:2004). sist-ts cen iso/ts 17892-12 (2004): geotechnical investigation and testing labo­ ratory testing of soil part 12: determination of atterberg limits (iso/ts 1789212:2004). sist-ts cen iso/ts 22476-11 (2008): geotechnical investigation and testing field testing part 11: flat dilatometer test (iso 22476-11:2005). veinović, ž., domitrović, d. & lovrić, t. (2007): pojava likvefakcije na području zagreba u prošlosti i procjena mogićnosti ponovne pojave tjekom jačeg potresa.– rud.-geol.-naft. zb., 19, 111–120. vukadin, v. (2013): the improvement of the loosely deposited sands and silts with the rapid impact compaction technique on brežice test sites.– engineering geology, 160, 69–80. doi: 10.1016/j.enggeo.2013.03.025 youd, t.l., idriss, i.m., andrus, r.d., arango, i., castro, g., chris­ tian, j.t., dobry, r., finn, w.d.l., harder, l.f., hynes, m.e., ishi­ hara, k., koester, j.p., liao, s.s.c., marcuson, w.f., martin, g.r., mitchell, j.k., moriwaki, y., power, m.s., robertson, p.k., seed, r.b. & stokoe, k.h. (2001): liquefaction resistance of soils: sum­ mary report from the 1996 nceer and 1998 nceer/nsf workshops on eva­ luation of liquefaction resistance of soils.– j. geotech. geoenvironmental eng., 127, 817–833. doi: 10.1061/(asce)1090-0241(2001)127:10(817) 2018 | 71/1 | 41–43 | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society in memoriam professor josip benić (“doktor jozo”, co-founder of the study of nannofosils in this region) (03.05.1939-26.07.2016) doi: 10.4154/gc.2018.03 a long time teacher of geology, professor josip benić passed away on july 26, 2016. his colleagues, friends, and students will remember a researcher with a profound knowledge of the mesozoic and cenozoic geology of croatia and its adjacent regions. during his professional career, josip benić proved to be a responsible and precise teacher who was always open to co-operation and constructive dialogue and who never hesitated to offer help and advice to his younger colleagues. josip benić was born in osijek on may 3rd, 1939. he graduated and received his phd degree from the faculty of science, university of zagreb (title of phd thesis was “calcareous nannoplankton and its application on biostratigraphy of cretaceous and palaeogene sediments of croatia”). in 1969, josip benić joined the faculty of science and, in 1976 became a full-time assistant professor at the department of geology (institute of geology and palaeontology). he served (1985 – 1989) as head of the institute of geology and palaeontology, and in 1996 he accepted the chairmanship in the department of mineral resources at the croatian geological survey, where he remained until he retired in 2004. josip benić remained a faculty member and part-time associate professor, teaching the geology of croatia and adjacent regions, and whenever it was necessary he joined a mapping course (both theoretical and field based). his studies of cretaceous – eocene calcareous nannofossils and their biostratigraphic and palaeoecological application began following the advice of professors vanda kochansky-devidé and milan herak. calcareous nannofossils are considered to be one of the most powerful biostratigraphic tools for marine carbonate sediments, especially in open ocean settings. the beginning of his research coincided with an intensive investigation into this group all over the world (by researchers including k. perchnielsen, e. martini, d. burky, w.w. hay, b.u. haq). it was a time when standardized quantitative counting methods were “discovered”, and when unambiguous taxonomy and highly resolved data sets provided high-quality biostratigraphic data. the first papers on nannofossil physiology and ecology and the parameters that controlled their distribution appeared, illustrating their application in facies reconstruction and palaeoclimatology and palaeoceanography reconstructions, for which they are still used today. however, the most time-consuming part of his research was gaining knowledge about nannofossil taxonomy. he overcame several major obstacles, the most important of which was that no local specialists were on hand to teach him and help with ambiguous specimens as well as his limited access to literature. however, it was worth the hard work. years of field sampling and hours and days studying the nannofossils under a light microscope resulted in the broadly accepted nannofossil biozonation for the late cretaceous and paleogene strata in the dinarides. he recognized and determined the age of two flysch belts in the dinarides. quite diverse sedimentation characterizes the northern flysch basin. in some areas sedimentation was continuous from the upper campanian to the middle eocene, while in others emersion took place across the k/pc boundary and the re-establishment of sedimentary environments suitable for flysch deposition varied from the middle to upper palaeocene. in the southern belt, flysch deposition followed shallow-water platform sedimentation, and corresponds to the middle and upper eocene in one zone and to the upper eocene in another. moreover, his conclusions about the variable duration of tectonic changes in the studied belts contrasted with the traditional view about the origin, age, and distribution of flysch. not to mention that subsequent studies have proved that he was right. his last work published in 2014 with another nannologist is homage to his work, in which he discussed and concluded about the age of the bosnian flysch, an enigma which he began to study in his thesis and in this work was finally completed. nowadays when quantitative studies present a very important tool in scientific ranking, his thesis is one of the most cited works from this area of study. after josip benić obtained his phd degree, he continued to investigate the calcareous nannofossils from different areas within the dinarides, and his results were published in several articles and chapters in books (see appendix). what made him unusual is the fact that he generously shared his knowledge and therefore he is acknowledged in many studies and papers. his palaeoecological interpretations of assemblages have yielded improved inter pretation and reconstruction of the evolution of the dinaric foreland basin, when shallow-water carbonate environments temporarily were suspended and when they again emerged. g eo lo gi a c ro at ic a geologia croatica 71/142 his pioneering work is seen through his publications. they are not numerous when counting the number of papers themselves, but they are very important. in his work the cretaceous and paleogene sediments within the dinarides are age interpreted by calcareous nannofossils, in some places in more detail, in others less, forming an excellent base for future studies on the dinarides. but these facts do not come close to capturing the wonderful essence of professor josip benić who was an individual of great intellectuality, humor, and generosity. he had a modest, honest, earnest, and very human personality as a professor, colleague, and friend. his generosity was, amongst other ways, reflected in sharing his time, advice, and especially helping with analysis necessary for the age attribution of deposits. his students are indebted to him for his generous guidance, the humor he knew to share with them, and his friendship and help. “caring mentor” is the best expression for him. if we want to summarize his professional work then we have to stress that he co-founded the study of calcareous nannofossils in croatia by classifying them and applying them to biostratigraphy. he was the pioneer in applying academic knowledge in petroleum geology and an expert in the geology of the dinarides. his work advanced the understanding of these fossils and more importantly, their role in applied geology. he enjoyed photography and was fascinated by the second world war (especially by the lives of some of the well-known soldiers and leaders, he liked the exposure of “secrets” behind the war scene). he indulged in spending time at and taking care of summerhouses (one on the lowest island in croatia and another one close to zagreb) and being with his family. he touched the lives of many students and colleagues in and out of the scientific world and has left a great legacy, personal and professional. we are going to miss him greatly! vlasta ćosović and matija panić bibliography chapters in books dragičević, i., tišljar, j., blašković, i. & benić, j. (1986): mehanizam taloženja krovinskih naslaga ležišta boksita kao odraz paleoreljefa podine (primjer boksitonosnog lokaliteta studena vrila, zapadna hercegovina) [depositional mo­ del for overlaying sediments of bauxite deposits as related to the paleokarst relief (as examplified by the bauxite-bearing area of studena vrila in western hercego­ vina) – in croatian].– in: trubelja, f. (ed.): naučne komunikacije 1.; odjeljenje tehničkih nauka 1. akad. nauka i umjetn. bih, sarajevo, 3–38. marinčić, s., šparica, m., pavelić, d. & benić, j. (1995): sedimenti gornjeg senona u dolini potoka vrapčaka [sediments of the upper senonian in the valley of the vrapčak creek – in croatian].– in: šikić, k. (ed.): geološki vodič medvednice. institut za geološka istraživanja; ina-industrija nafte d.d., zagreb, 51–52. original scientific papers in cc and other journals benić, j. (1975): vapnenački nanoplankton eocenskog fliša otoka paga [calcarous nannoplankton from eocene flysch on the island of pag, croatia – in croatian].– geol. vjesnik, 28, 19–23. jelaska, v., bulić, j., velimirović, z., bauer, v. & benić, j. (1976): prilog potpunijem poznavanju stratigrafije vučjaka i trebovca (sjeverna bosna) [some observations on the stratigraphy of the vučjak and trebovac area (north bosnia) – in croatian].– geol. vjesnik, 29, 389–395. polšak, a., devidé-nedêla, d., turnšek, d., gušić, i. & benić, j. (1978): biostratigrafski odnosi grebenskih, prigrebenskih i bazenskih naslaga gornje krede u području donjeg orešja, si medvednica [biostratigraphy of upper creta­ ceous reef, forereef and basin deposits at donje orešje (mt. medvednica, north croatia) – in croatian].– geol. vjesnik, 30/1, 189–197. benić, j. & bukovac, j. (1983): paleocensko-donjoeocenski fliš i vapnenački nanoplankton zapadno od duga resa (hrvatska) [paleocene-lower eocene flysch and calcareous nannoplankton from the area west of duga resa, croatia – in croatian].– geol. vjesnik, 36, 13–20. benić, j., benček, đ. & magdalenić, z. (1983): paleocenski fliš i vapnenački nanoplankton u području sjeverno od vrginmosta (hrvatska) [palaeocene flysch and calcareous nannoplankton in the area north of vrginmost, croatia – in croatian].– geol. vjesnik, 36, 21–51. dragičević, i., benić, j. & blašković, i. (1985): novi stratigrafski podaci o paleogenskim klastitima studenih vrila – zapadna hercegovina [new stratigraph­ ica data on the paleogene clastics at studena vrila, western hercegovina – in croatian].– geol. vjesnik, 38, 31–34. dragičević, i., blašković, i., tišljar, j. & benić, j. (1992): stratigraphy of paleogene strata within the mesihovina-rakitno area (western herzegovina).– geol. croat., 45, 25–52. lučić, d., benić, j., stanković, d. & miletić, d. (1993): cretaceous/tertiary boundary from the koraljka-1 off-shore well (sw of zadar, adriatic sea).– geol. croat., 46/1, 41–61. sakač, k., benić, j., bahun, s. & pecinger, v. (1993): stratigraphic and tectonic position of paleogene jelar beds in the outer dinarides.– natura croatica, 2/1, 55–72. sakač, k., šinkovec, b., durn, g. & benić, j. (1993): boksiti i jelar-naslage [the bauxite and jelar-beds – in croatian].– rud. geol. naft. zbornik, 5, 59–64. benić, j., blašković, i. & tomić, v. (1997): professor herak’s contribution to regional geology and geotectonics.– geol. croat., 50/2, 157–160. benić, j., blašković, i. & tomić, v. (1997): regional geology and geotectonic.– geol. croat., 50, 101–110. tari-kovačić, v., kalac, k., lučić, d. & benić, j. (1998): stratigraphic analysis of paleogene beds in some off-shore wells (central adriatic area, croatia).– dela-opera: sazu, 34/2, 203–242. marjanac, t., babac, d., benić, j., ćosović, v., drobne, k., marjanac, lj., pavlovec, r. & velimirović, z. (1998): eocene carbonate sediments and sea-level changes on the ne part of adriatic carbonate platform (island of hvar and pelješac peninsula, croatia).– dela-opera: sazu, 34/2, 243–254. moro, a., ćosović,v., benić, j. & dokmanović, j. (2010): taxonomy of rudists from the campanian transgressive sediments of brašljevica, donje orešje and sv. martin, northern croatia. – turkish j. earth sci., 19/5, 613–633. ćorić, s. & benić, j. (2014): first evidence of the palaeogene age of the bosnian flysch unit (dinarides, bosnia and herzegovina).– rendiconti online della società geologica italiana, 31, 46–47. proceedings of conferences drobne, k., pavlovec, r., šikić, l. & benić, j. (1979): excursion f, pićan, istria-cuisian, lutetian.– in: guidebook 16th european micropal. colloquium yugosl., ljubljana, f177–f182. polšak, a., dragičević, i., tomić, v., devidé-nedêla, d. & benić, j. (1982): tektonska i paleogeografska dinamika u rubnoj zoni jadranske ploče: primjer kredno-paleogenskog kompleksa jajce [tectonic and paleogeographic dynam­ ics in the marginal zone of the adriatic plate: an example of cretaceous-paleogene bauxite-bearing area of jajce – in croatian].– in: 10th jub. kongr. geol. jugosl., budva, 1, 605–623. pavlovec, r., drobne, k., ćosović, v., šikić, l. & benić, j. (1991): the pićan profile, middle and upper cuisian, lower and middle lutetian.– in: drobne, k. & pavlovec, r. (eds.): 2nd meeting igcp project 286, early paleogene benthos. introduction to the paleogene sw slovenia and istria, field-trip guidebook, (postojna), ljubljana, 73–79. abstracts mihelčić, g., juračić, m., kniewald, g. & benić, j. (1990): geološki i geotektonski preduvjeti stvaranja estuarija rijeke krke [geological and geotectonic preconditions for the development of the river krka estuary – in croatian].– in: 12th kongr. geol. jugosl., ohrid (1990), 4, p. 354. benić, j. (1991): the age of the istria flysch deposits based on calcareous nannofossils.– in: 2nd meeting igcp project 286: early paleogene benthos: introduction to the paleogene sw slovenia and istria, field-trip guidebook, (postojna), ljubljana, p. 25. lučić, d., benić, j., stanković, d. & miletić, d. (1991): biostratigraphy of carbonate deposits of upper cretaceous and paleogene in off-shore well koraljka-1, southwest of zadar (croatia, adriatic sea).– in: 2nd intern. symp. on the adriatic carbonate platform, zadar (1991), poster presentation. zagreb, p. 108 marjanac, t., benić, j., ćosović, v., drobne, k., marjanac, lj. & velimirović, z. (1991): sea-level changes and eocene sequence in central dalmatia, croatia.– in: 2nd intern. symp. on the adriatic carbonate platform, zadar (1991), abstracts. zagreb, p. 59. galović, i., koch, g. & benić, j. (2000): middle miocene phytoplankton zones in markuševec area (mt. medvednica, croatia).– in: burnett, j.l. (ed.): j. of nannoplankton research. courier forschungsinstitut senckenberg, bremen, p. 98. galović, i., miknić, m., vrsaljko, d. & benić, j. (2000): stratigraphy of the markuševec column (mt. medvednica, croatia). pancardi 2000: pannonian basin, carpathian and dinaride sytem: geological meeting on dynamics of ongoing orogeny: abstracts.– in: tomljenović, b., balen, d. & saftić, b. (eds.): vijesti hrv. geol. društva 37/3, 1–154. hrv. geol. društvo, zagreb, 44–45. g eologia c roatica 43ćosović and panić: in memoriam professor josip benić hernitz kučenjak, m., premec fuček, v., stanković, d., mesić, i.a. & benić, j. (2003): biostratigraphical, lithological and paleoecological aspects of the late cretaceous (maastrichtian) and paleogene sediments in the jihar-1 well (palmyra region, syria).– in: vlahović, i. (ed.): 22nd ias meeting of sedimentology – opatija: abstracts book. institute of geology, zagreb, p. 79. moro, a., ćosović, v., benić, j. & dokmanović, j. (2008): taxonomy of rudists from the campanian transgressive sediments of brašljevica, orešje and kalnik mt., northern croatia. eighth international congress on rudists: abstracts.– dokuz eylul university, izmir, p. 56. moro, a., horvat, a., ćosović, v., benić, j., sremac, j., bermanec, v. (2011): campanian rudist-bearing shallow-water deposits of northern croatia and slovenia.– in: mitchell, s.f. (ed.): the ninth international congress on rudist bivalves : abstracts, articles and field guides. uwi geology museum, kingston (jamaica), p. 25. thesis and reports benić, j. (1975): paleogenski nanofosili hrvatskog primorja (od istre do ravnih kotara) [paleogene nannofosils of the croatian littoral (from istria to ravni kotari) – in croatian, with an english abstract].– unpubl. master’s thesis, faculty of science, university of zagreb, 82 p, 20 pls. benić, j. (1983): vapnenački nanoplankton i njegova primjena u biostratigrafiji krednih i paleogenskih naslaga hrvatske [calcarous nannoplankton and its applica­ tion in the biostratigraphy of cretaceous and paleogeneous deposits of croatia – in croatian, with english abstract].– unpubl. doctoral thesis, faculty of science, university of zagreb, 159 p. benić, j. (1992): biostratigrafija tercijara jadranskog podmorja na osnovi vapnenačkih nanofosila [biostratigraphy of tertiary of the adriatic sea based on calcarous nannofosils – in croatian].– unpubl. report, ina-naftaplin, služba za istraživanje; hrvatski prirodoslovni muzej, zagreb, 104 p, 14 pls. ab stra ct upper westphalian coals are usually rich in organic-matter of different plant taxa, including gymnosperms. the assemblage from kalinovo (eastern ukraine) is exceptional in being dominated by sphenophyllum, both cuticles and conducting tissues. sphenophyllum cuticles are easily distinguished by their parallel oriented cells with sinuous anticlinal walls, and paracytic stomata on the abaxial cuticle. tracheids with multiseriate bordered pits that occur in sphenophyllum can be also found in the calamitaceae and some pteridosperms. however, rectangular shaped remains of parenchyma cell strips along the radial wall of tracheids are only known in sphenophyllum. keywords: sphenophyllum, dispersed cuticles, carboniferous – westphalian, donets basin dispersed cuticles and conducting tissue of sphenophyllum brongniart from the westphalian d of kalinovo, donets basin, ukraine  zbyněk šimůnek1 and jan bureš2 1 czech geological survey, klárov 131/3, 118 21 praha 1, czech republic; (zbynek.simunek@geology.cz) 2 west bohemian muzeum plzeň, kopeckého sady 2, 30100 plzeň, czech republic; (rallus@seznam.cz) doi: 10.4154/gc.2015.01 lar conditions in a peat-swamp, however, they come from different geographical regions and stratigraphical horizons. sphenophyllum priveticense is known from the lower bolsovian (middle westphalian) of central bohemia, whereas the sphenophyllum sp. studied in this paper occurs in the uppermost asturian (uppermost westphalian) of the kalinovo locality, donets basin, ukraine. 2. geological setting the carboniferous sequence in the research area transgressively overlies marine and younger terrestrial devonian deposits. carboniferous and permian deposits in the southeastern part of the donets basin achieve a thickness of 12 km. coal-bearing cyclothems consist of basinal marine to shallow marine claystones and limestones with marine fauna; and terrestrial sandstones, siltstones, claystones with roots, and coal (havlena, 1965). lithostratigraphic units are marked with letters and their subunits by letters with numbers; limestones with capital letters and coal seams above the limestone with corresponding small letters (fig. 1). geologia croaticageologia croatica 1. introduction the genus sphenophyllum brongniart belongs to the sphenopsids and is characterized by linear, spatulate or fanshaped leaves that extend up to several cm in length. the leaves are arranged along the axis in nodal whorls of six or nine. the name sphenophyllum is used for both impressioncompression and petrified permo-carboniferous samples. although more than 100 compression-impression and petrified sphenophyllum species have been described in the world, cuticles are known only from 15 of those species. the cuticles known so far, have been prepared by maceration of coalified sphenophyllum leaves; studied directly on fossils by means of optical techniques (barthel, 1997); or studied in sections of coal balls (good, 1973). this paper brings unique information on sphenophyllalean cuticles and conducting tissue obtained directly from the coal. unfortunately, taxonomic affiliation was not possible because the leaf outline is not preserved. similar cuticles have only been previously observed in sphenophyllum priveticense libertín et al., 2014. we presume that both species lived under simigeologia croatica 68/1 1–9 3 figs. 1 tab. 3 pls. zagreb 2015 geologia croatica 68/1geologia croatica 2 sandstones (aizenverg et al. 1975). mudstones with roots and coal seam no. n3 (0.3 m thick) are located above the sandstone. a sample from this coal seam from the kalinovo locality, which is situated about 55 km w. from luhansk in the donets basin (fig. 2) was macerated for dispersed cuticles (sample position: n = 48° 35.355’; e = 38° 31,956’; h = 123 m). above the coal seam, there are mudstones and claystones of lacustrine origin. stigmaria occurs in the rooted horizon, while linopteris obliqua (bunbury) zeiller, neuropteris ovata hoffmann, laveineopteris rarinervis (bunbury) cleal et al., alethopteris sp., annularia sphenophylloides (zenker) gutbier and pecopteris sp. have been determined above the coal seam (aizenverg et al. 1975). this flora is of asturian (westphalian d) age and is the youngest westphalian flora found in the donets basin. 3. material and methods in order to obtain cuticles authors applied a new method. a 2.5 g sample of coal was macerated in schulze’s reagent: 35 ml concentrated (65%) nitric acid (hno3) and 1.5 g of potassium chlorate (kclo3) for 2 days and 18 hours. the black residue was fully washed under running water in a sieve and then treated with 10% potassium hydroxide (koh) for up to one hour. during this process, the “coal matter” was completely dissolved and only the cuticles and vascular tissue remained. the cuticles were stained in safranin, bismarck brown, malachite green or neutral red, and mounted in glycerine jelly, or were attached to an sem stub for observation under a scanning electron microscope (sem). about 30 foliar fragments of cuticles and a similar number of conducting tissue fragments were mounted on six slides. about ten cuticular fragments are longer than 1 mm (up to 1.3 mm), and represent both the adaxial and abaxial leaf surfaces. some fragments of conducting tissue were up to 3 (4) mm long. the dispersed cuticles are stored in slides no. 595/1–6. figure 1: stratigraphy of the pennsylvanian of the donets basin. the coal sample was taken from the upper part of the section. adapted from privalov et al. (2005). limestone n3 in the isayevskaya suite (formation) is overlain by a 7 m thick sequence of unfossiliferous bluishgrey claystones and siltstones and about 30 m of fine-grained figure 2: map of ukraine with kalinovo locality highlighted. šimůnek and bureš: dispersed cuticles and conducting tissue of sphenophyllum brongniart from the westphalian d of kalinovo, donets basin, ukraine geologia croatica 3 4. systematics systematics performed according to cleal & thomas (1995) class equisetopsida (‘horsetails’) order bowmanitales (‘sphenophylls’) meyen, 1978 family bowmanitaceae meyen, 1987 genus sphenophyllum brongniart, 1828 sphenophyllum sp. (fig. 3, pls. 1, 2, 3) description: adaxial cuticle: the cells are elongate, more or less fusiform or elongate tetragonal in shape with coarsely sinuous anticlinal walls that affect the original cell shape. the cells are oriented parallel to the veins, and are 150–300 μm long and 25–50 μm wide. the costal (vein) areas are usually prominent with original black vascular tissue (pl. 1, fig. 2), which is about 100 μm wide. when this tissue is not preserved (pl. 1, fig. 1), the costal area is about 50 μm wide and shows narrow cells only 15–20 μm wide. abaxial cuticle: the cells have essentially the same shape and dimensions as the cells of the adaxial cuticle. the difference is in the presence of stomata (pl. 1, figs. 3–4). the stomata tend to be concentrated in “bands” along the veins and they are oriented parallel to the veins. the guard cell pairs are fusiform or elliptical, 26–32 μm long and 10–14 μm wide (pl. 1, figs. 4, 6, pl. 2, fig. 4). each stoma has two lateral subsidiary cells (paracytic stomatal type), one of which is shorter – 78–90 μm long; and the longer is 176–192 μm long. both cells have approximately the same width – 20–35 μm. the cuticles in scanning electron microscope have very fine striated periclinal walls in outer view (pl. 2, fig. 1) and the anticlinal walls are prominent in the inner view (pl. 2, figs. 2–4b). using the same approach as described by poole & kürschner (1999) stomatal density and stomatal index were counted from several cuticle fragments; the area of each fragment was 0.1–0.15 mm2. the stomatal density of sphenophyllum sp. is 83–90 stomata per mm2 and the stomatal index is 20.5–23. conducting tissue: fourteen tracheids from slides 595/1, 2, 3 and 5 were studied. fragments of tracheids have walls perforated mainly by multiseriate bordered pits (pl. 3, figs. 1, 3), which locally become in reticulate cell wall thickening (pl. 3, fig. 4). bordered pits are free, and according to the number of their rows and tight configuration they belong to the alternate pitting surface type . the number of bordered pit rows on the tracheid wall is (2)–4–6. bordered pits have a circular to elliptical shape and approximately the same dimension. the tracheids are 60–100–(125) mm wide. the thickening on some tracheids is interrupted by the walls of parenchyma cells that form a rectangular outline on the tracheid (pl. 3, fig. 2). due to the fragmentary size of the preserved tracheids, it was not possible to determine their original total length. 5. remarks fragments of the xylem – tracheids were found in association with the sphenophyllum cuticles. according to taylor et al. (2009, p. 206), annular or helical thickenings of tracheids are most often found in the earliest matured primary xylem. secondary xylem is made up predominantly of pitted tracheids, although some plant groups also have secondary xylem tracheids. bordered pits in tracheal elements are according to němejc (1963, p.76) very rare in many pteridophylls (pteridophyta). it is common in equisetopsids (equisetopsida) and in many pteridosperms and gymnosperms. 6. sphenophyllum cuticles and their comparison most species of sphenophyllum brongniart have irregu larly isodiametric to elongate epidermal cells that usually posses sinuous anticlinal walls. stomatal complexes occur on the abaxial surface of the leaf and consist of two guard cells with polar and circumpolar thickenings, and two paracytic lateral subsidiary cells. subsidiary cells may have the same shape and size as normal epidermal cells, or they can differ. one subsidiary cell is usually distinctly larger than the other (taylor et al. 2009). these characteristics fit very well with the cuticles described above. individual species differ in the distribution of the stomata, the orientation and size of the guard cells, and the shape, arrangement and size of the intercostal cells (table 1). barthel (1997) distinguished two groups among the sphenophyllum species. group 1 consists of sphenophyllum cuneifolium, s. emarginatum, s. majus abbot (=s. geinitzii storch), s. thonii, s. speciosum. s. longifolium and s. saxonicum. this group is hypostomatic, with sinuous anticlinal walls and larger cells. group 2 consists of sphenophyllum oblongifolium and the anatomically preserved species s. quadrifidum renault and s. reedae good. in this group, the epidermis has rectangular cells with straight anticlinal walls. figure 3: a paracytic stoma of sphenophyllum sp. from kalinovo locality. note the uneven lateral subsidiary cells, ls = lateral subsidiary cells, g = guard cells. scale bar = 50 μm. geologia croatica 68/1geologia croatica 4 plate 1 sphenophyllum sp., locality kalinovo, donets basin, coal seam n3, upper asturian (moscovian, pennsylvanian) 1 and 2 – adaxial cuticle, slide 595/3, scale bar = 100 μm; 2 – note black costal area. 3–6 – abaxial cuticle; fig. 3 – cuticle with black costal area and holes where guard cells, have fallen out, slide 595/3, scale bar = 100 μm; 4 – detail of a stomatal complex with guard cells, scale bar = 20 μm; 5 – cuticle with 5 stomatal complexes, slide 595/5, scale bar = 50 μm; 6 – close up to two stomatal complexes from fig. 5 scale bar = 20 μm šimůnek and bureš: dispersed cuticles and conducting tissue of sphenophyllum brongniart from the westphalian d of kalinovo, donets basin, ukraine geologia croatica 5 plate 2 sphenophyllum sp., loc. kalinovo, donets basin, coal seam n3, upper asturian (moscovian, pennsylvanian) cuticles in scanning electron microscope. sem stub no. 84. 1 – adaxial or abaxial cuticle in outer view. note the periclinal walls with very fine longitudinal striations and sinuous anticlinal walls, scale bar = 50 μm. 2 – adaxial or abaxial cuticle in inner view. note prominent sinuous anticlinal walls, scale bar = 50 μm. 3 – abaxial cuticle with a stoma (s) in inner view, scale bar = 50 μm. 4 – close up of the stomatal complex from fig. 3, scale bar = 20 μm. geologia croatica 68/1geologia croatica 6 plate 3 typical structure of secondary xylem tracheids in the studied specimens resembling the tracheid structure of sphenophyllum sp. 1 – secondary xylem tracheids with multiseriate bordered pits, the shape of the bordered pits is circular – elliptical, slide 595/3. scale bar = 100 µm. 2 – view of the tracheid walls in places where strips of parenchyma cells were attached. p – tracheid surface (? wall) in the place where parenchyma cells were attached. c – contiguous tracheid wall is demarcated and perforated. the tracheid has reticulate cell wall thickening. slide 595/3, scale bar = 100 µm. 3 – a close up of tracheidal wall with pentastichous pitting of a circular shape. sem stub 84. scale bar = 20 µm. 4 – a close up of a tracheidal wall, a – circular bordered pits, b – elliptical bordered pits, c – reticulate cell wall thickening, the tracheid wall is partly sagging. sem stub 84, scale bar = 20 µm. šimůnek and bureš: dispersed cuticles and conducting tissue of sphenophyllum brongniart from the westphalian d of kalinovo, donets basin, ukraine geologia croatica 7 the sphenophyllum sp. described in the present paper belongs to group 1. the elongate cells with coarsely sinuous anticlinal walls occur in many species: e.g. sphenophyllum emarginatum, s. cuneifolium, s. thonii, s. majus abbot (non bronn) (=s. geinitzii), s. kobatake and s. zwickawense. however, the cell size in the present species (150–300 μm) is rather large compared to all the species mentioned above, where it is usually only up to 200 μm. the exception is the newly described sphenophyllum priveticense libertín, bek et drábková, 2014, in which the cells are 125–350 μm long and so more comparable to our samples of sphenophyllum sp. however, they differ in other characteristics (see tab. 1) and it is unlikely that they belong to the same species, especially as sphenophyllum priveticense is of early bolsovian age whereas the present sphenophyllum sp. is of latest asturian age. sphenophyllum guard cells are usually reniform and the outline of the pair is elliptical. their size differs according to species, however some overlap exists. our sphenophyllum sp. has medium sized guard cells among the sphenophylls, 28–32 μm in length. the smallest ones are known from permineralised s. multirame (only 15 μm long) and the largest ones are known in four species s. emarginatum (31– 57 μm), s. apiciseratum (34–54 μm), s. koboense (27–54 μm) and s. priveticense (45 μm). an important feature is also the shape of the subsidiary cells. many species have two lateral subsidiary cells per stoma (usually one of them is larger than the other); they are of the same shape as normal epidermal cells in sphenophyllum sp., s. emarginatum, s. thonii, s. speciosum, s. longifolium, s. apiciseratum, s. koboense and s. priveticense. according to libertin et al. (2014), the stomatal complex of s. priveticense is anomocytic, but it seems that all those mentioned above have paracytic stomata. in other species, the subsidiary cells differ significantly from the ordinary epidermal cells: sphenophyllum cuneifolium, s. thonii, s. geinitzii (s. majus abbot), s. saxonicum, s. multirame and s. reedae. some species have trichomes and papillae on the adaxial surface of the leaves: sphenophyllum majus, s. speciosum, s. saarensis, s. trichomatosum stur and probably also s. sewardii batenburg (libertín et al. 2014). no trichomes or emergences have been observed on cuticles from sphenophyllum sp. from kalinovo. 7. comparison of conducting elements the characteristic pitting of the tracheid walls in the studied samples corresponds to the description of secondary xylem anatomy of the sphenophyllum plant as mentioned in table 1: epidermal structures of sphenophyllum species. species (c-compression; p-petrification) distribution of stomata orientation of guard cells guard cell size [mm] subsidiary cells no./specialised in shape and size shape and arrangement of intercostal cells intercostal cell size [mm] shape of anticlinal walls references s. emarginatum brongniart [c] random usually parallel to veins 31-57x5-18 2/no long, irregular 79-179x26-50 coarsely sinuous batenburg (1977), (1981) s. cuneifolium (sternberg) zeiller [c] random parallel to veins 25x15 2/few long, irregular 80-200x30-60 coarsely sinuous barthel (1997) s. thonii mahr [c] random to stripped parallel to veins 30x20 2/yes long, irregular 100-200x20-30 coarsely sinuous meyen (1970) s. majus abbot non bronn (=s. geinitzii storch) [c] random random 30x20 5-6/few long, irregular 40-60-10-15 coarsely sinuous abbot (1958) s. speciosum (royle) zeiller [c] random random 25x15 2/no long, irregular 100-200x30-70 sinuous pant & mehra (1963) s. longifolium (germar) gutbier[c] random parallel to veins 20-28x12-15 2/no longitudinal rows 140-200x40-55 finely sinuous barthel (1997) s. saxonicum remy & remy [c] random parallel to veins 25x15 2/few longitudinal rows 100-200x35-40 finely sinuous barthel (1997) s. oblongifolium (germar & kaulfuss) unger [c] ? ? ? ? rectangular in rows 100-180x15-25 straight barthel (1997) s. multirame darrah (p) in 2 sunken rows or furrows random 15x10 2-4/yes long, irregular 100-150x15-25 finely sinuous good (1973) s. reedae good (p) random parallel to veins 25x18 3-5/few rectangular in rows 70-150x20-30 straight good (1973) s. apiciseratum yao et al. [c] random random 34-54x14-24 2/no irregular 65-147x 41-112 coarsely sinuous yao et al. (2000) s. koboense kobatake [c] random (near veins) random 27-54x10-24 2/no long, irregular 81-189x20-41 finely to coarsely sinuous yao et al. (2000) s. zwickauvense storch [c] ? ? ? ? longitudinal rows 60-177x14-52 sinuous batenburg (1981) s. priveticense libertín, bek & drábková [c] in rows parallel to veins 45x15 2/few longitudinal rows 125-350x50-60 sinuous libertín et al. (2014) s. sp. [dispersed] near veins parallel to veins 26-32x10-14 2/no longitudinal rows 150-300x25-50 coarsely sinuous present study only well preserved compression [c] species, and petrifaction (p) species whose foliar grooss morphology is known, have been included. other compression species are known only by fragments without stomata (see baten burg, 1981). geologia croatica 68/1geologia croatica 8 boureau (1964, p. 98, 99), who figured sphenophyllum with multiseriate bordered pits. he also figured the distribution of parenchyma cell strips along the radial walls of a tracheid. it has been shown that strips of parenchyma cells created a rectangular contour on the radial wall of the tracheids. these contours are the only remnants of parenchyma cells. taylor et al. (2009) also described tracheids of secondary xylem with circular–eliptical bordered pits on the lateral walls in sphenophyllum plurifoliatum williamson et scott. similarly, bureš et al. (2013) described tracheids with circular–elliptical bordered pits in sphenophyllum cf. myriophyllum crépin. batenburg (1982) described xylem with scalariform thickenings and elements with uni or multiseriate bordered pits in sphenophylllum speciosum zeiller (pant & mehra). rössler & noll (2007 p. 174) described a similar structure in the secondary xylem of calamitea striata cotta (calamitaceae). cell walls show simple to bifurcate scalariform to reticulate thickening with elongate oval pits in radial and tangential sections. multiseriated bordered pits of tracheids are common in pteridosperms as noted by andrews (1940), němejc (1968), and taylor et al. (2009). 8. conclusion cuticles and conducting tissue of sphenophyllum brongniart have for the first time been identified in the dispersed cuticle spectrum. many sphenophyllum species have the same cuticular pattern, so it is difficult to identify sphenophyllum species only using cuticles, as noted by barthel (1997). nevertheless, as it has paracytic stomata and elongate cells with sinuous anticlinal walls, the sphenophyllum from kalinovo clearly belongs to group 1 (sensu barthel 1997) together with sphenophyllum cuneifolium, s. emarginatum, s. thonii, s. speciosum. s. longifolium, s. saxonicum and s. priveticense. although the kalinovo species has medium-sized guard cells that fit with several species, together with sphenophyllum priveticense libertín, bek et drábková, 2014, it has the longest cells that have been reported so far in a sphenophyllum species, 300 – 350 μm long, in contrast to usually no more than 200 μm long seen in other species. despite the similarity of their cuticles, the sphenophyllum sp. from kalinovo and sphenophyllum priveticense cannot be regarded as conspecific as the former is stratigraphically much younger. sphenophyllum sp. was discovered in kalinovo coal, and s. priveticense was found in a tuff that buried the peat-swamp “in situ” and also contained many peat-forming floral elements. it is likely, therefore, that both sphenophyllum sp. and s. priveticense lived in similar habitats. libertín et al. (2014) supposed that sphenophyllum priveticense lived in peat-swamps with a high water table and also in slightly drier habitats with a transition to an omphalophloios-phase. maybe the larger cell dimension is caused by living in such an environment. it is not possible to systematically classify the studied tracheid fragments of the genus sphenophyllum sp. based on tracheid thickening. a similar structure of tracheids is also common in the other plant groups from the pennsylvanian (calamitaceae, pteridosperms). any palaeoecological interpretation based on the tracheids is not possible, as their width depends on vegetation conditions, and we are not sure if all the studied tracheids in fact belong to this sphenophyllum. acknowledgement this study was part of the international geoscience programme (igcp project 575) and the gacr project p210/10/0232. the authors are obliged to v. i. poletaev, n. boyarina and a. schegolev (kiev, ukraine) for guiding in the field and to c.j. cleal (cardiff, uk) for checking of the text. references abbot, m.l. (1958): the american species of asterophyllites, annularia and sphenophyllum.– bulletins of american palaeontology, 38, 289–390. aizenverg, d.e., lagutina, v.v., levenshtein, m.l., popov, v.s. (eds.). (1975): viii international congress on carboniferous stratigraphy and geology.– field excursion guidebook for the donets basin, moscow 1975, 360 p. andrews, h.n. (1940): on the stelar anatomy of the pteridosperms with particular reference to the secondary wood.– annals of the missouri botanical garden, 27, 51–118. barthel, m. (1997): epidermal structures of sphenophylls.– review of palaeobotany and palynology, 95, 115–127. batenburg, l.h. (1977): the sphenophyllum species in the carboniferous flora of holz (westphalian d, saar basin, germany).– review of palaeobotany and palynology, 24, 69–99. batenburg, l.h. (1981): vegetative anatomy and ecology of sphenophyllum zwickaviense: s. emerginatum and other compression species of sphenophyllum.– review of palaeobotany and palynology, 32, 275–313. batenburg, l.h. (1982): “compression species” and “petrifaction species” of sphenophyllum compared.– review of palaeobotany and palynology, 36/3–4, 335–359. boureau, e. (1964): traité de paléobotanique iii. sphenophyta, noeggerathiophyta.– masson et cie, éditeurs, paris, 544 p. bureš, j., opluštil, s, pšenička, j. & tichávek, f. (2013): brouskový obzor (bolsov) na lokalitě kamenný újezd u nýřan (plzeňská pánev) – the whetstone horizon (bolsovian) in the locality kamenný újezd near nýřany (pilsen basin).– zprávy o geologických výzkumech v roce 2012, 12–19. cleal, c.j. & thomas, b.a. (1995): palaeozoic palaeobotany of great britain.– chapman & hall, london, 295 p. good, c. w. (1973): studies of sphenophyllum shoots. species delimitation within the taxon sphenophyllum.– american journal of botany, 60, 929–939. havlena, v. (1965): geologie uhelných ložisek iii.– nakladatelství čsav, praha, 382 p. libertín, m., bek, j. & drábková, j. (2014): new sphenophyllaleans from the pennsylvanian of the czech republic.– review of palaeobotany and palynology, 200, 196–210. meyen, s.v. (1970): epidermisuntersuchungen an permischen landpflanzen des angaragebietes.– paläontologische abhandlungen, b, 3/3–4, 523–552. šimůnek and bureš: dispersed cuticles and conducting tissue of sphenophyllum brongniart from the westphalian d of kalinovo, donets basin, ukraine geologia croatica 9 meyen, s.v. (1987): osnovy paleobotaniki. spravočnoe posobie.– m. nedra, moskva, 403 p. němejc, f. (1963): paleobotanika ii.– nakladatelství čsav, praha, 523 p. němejc, f. (1968): paleobotanika iii.– nakladatelství čsav, praha, 480 p. pant, d.d. & mehra, b. (1963): on the epidermal structure of sphenophyllum speciosum (royle) zeiller.– palaeontographica, b, 112, 51–57. poole, l. & kürschner, w.m. (1999): stomatal density and index: the practice.– in: jones, t.p. & rowe, n.p. (eds.): fossil plants and spores. modern techniques.– geological society, london, 257–260. privalov, v.a., izart a., sachsenhofer, r.f., antsiferov, v.a. & panova, e.a. (2005): pennsylvanian source rocks from the donets basin (ukraine).– extended abstracts of eage 67th conference & exhibition, madrid, spain, 13–16 june 2005. rössler, r. & noll, r. (2007): calamitea cotta, the correct name for calamitean sphenopsids currently classified as calamodendron brongniart.– review of palaeobotany and palynology, 144/3–4, 157–180. taylor, t., taylor, e.l. & krings, m. (2009): paleobotany. the biology and evolution of fossil plants.– elsevier inc., 1252 p. yao, z.-q., liu, l.-j., mapes, g. & rothwell, g.w. (2000): leaf morphology and cuticular features of sphenophyllum in the gigantopteris flora from the south china.– review of palaeobotany and palynology, 110, 67–92. manuscript received october 10, 2014 revised manuscript accepted january 24, 2015 available online february 27, 2015 2020 | 73/1 | 59–67 | 8 figs. | 1 tab. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society sedimentary and structural setting of the aptian reservoir deposits in the kasserine area, west-central tunisia khaled lazzez1, marzouk lazzez2, moez ben fadhel3, ramla ben rabah2 and taher zouaghi4,5 1 université tunis el manar, département de géologie, faculté des sciences de tunis, 2092 tunis, tunisia; (lazzezkhaled@yahoo.com) 2 entreprise tunisienne d’activités pétrolières (etap), 54 avenue mohamed v, 1002 tunis, tunisia; (marzouk.lazzez@etap.com.tn) 3 institut supérieur des sciences et technologies de l’environnement, département de biotechnologie, borj cédria, tunisia; (moez.benfadhel@yahoo.fr) 4 king abdulaziz university, faculty of earth sciences, department of geoexploration, 21589 jeddah, saudi arabia; (taher.zouaghi2018@gmail.com; tzouaghi@kau.edu.sa) 5 certe, pôle technologique de borj cédria, laboratoire de géoressources, 8020 soliman, tunisia doi: 10.4154/gc.2020.06 abstract the aptian hydrocarbon-producing reservoirs, in the onshore semmama and douleb oil fields of west-central tunisia are characterized by a heterogeneous flow with continuous decline. petroleum exploration in this area requires detailed knowledge of the structural development of the basin and its relationship to the reservoir sequence and the source rock distribution. the structural configuration of west-central tunisia is characterized by ne-sw, nw-se and n-s deepseated faults, which outline tectonic structures and it is influenced by triassic salt intrusions. during the aptian period, the basin was extensive and shallow at the center, though moderately deep to the north. the northeast-southwest dominated synsedimentary extensional tectonics induced high and subsiding zones and thus controlled sedimentary deposition. the aptian reservoir is characterized by the lateral variation of sedimentary facies. the first zone, dominated by dolomitic lithofacies has been proven as a petroleum reservoir. the second zone corresponds to carbonate reef and para-reef facies. the third zone, trending north-south is characterized by shallow marine sedimentation, punctuated by episodes of detrital influx. the early aptian is outlined by the emergence of kairouan island that took place in central tunisia. this study facilitated mapping of the areas exhibiting hydrocarbon reservoir potential which resulted from the conjunction of extensional tectonics and salt ascension. article history: manuscript received may 13, 2019 revised manuscript accepted february 18, 2020 available online february 29, 2020 keywords: aptian, west-central tunisia, sedimentary facies, depositional environment, reservoirs structuring well and seismic data. a comparison with the surface data was conducted to better understand the dynamics of sedimentation within this region. well log analysis of the aptian layers was undertaken to verify the petrophysical characteristics of the reservoir. a geometric and structural model that shows the spatial distribution and evolution of the reservoir units, between the high platform and subsiding basin, is a potential exploration objective in west-central tunisia. 2. geological setting the west-central tunisia outcrops, belonging to the eastern atlasic domain, are mainly composed of mesozoic and cenozoic layers deposited in several synclines, tilted blocks, and half graben basins (e.g. chihi & ben ayed, 1991; saïdi & belayouni, 1994; chihi, 1995; zouaghi et al., 2011, 2013). the structural framework (fig. 1) is characterized by major ne-sw reverse faults, that outline major atlasic folds, and by other regional nw-se and e-w strike-slip faults that outline grabens and subsiding troughs. other n-s transcurrent lineaments have dissected the pre-existing structures (e.g. martinez et al., 1990; chihi, 1995; zouaghi et al., 2011, 2013). tectonic movements have controlled deformation within the atlasic domain and, therefore, influenced sedimentary infilling and evolution of the basin and the platform structures (figs. 2 and 3). aptian structuring and sedimentary distribution seem to be generated by regional nnw–sse aptian extensional and/or transtensional tectonic deformation that changed to a ne–sw direction at the end of the aptian (zouaghi et al., 2011, 2013). 1. introduction the area of central tunisia hosts several productive petroleum systems including the douleb, semmama, and tamesmida oil fields (figs. 1 and 2). for many years, aptian reservoir layers have been unexplored and untested in central tunisia. recently, wells have been drilled to investigate the serdj formation in the study area. oil-producing wells, developed in the douleb and semmama area, penetrate the aptian dolomitic reservoir. the exploration challenge was to identify the characteristics of the traps, related to the structural framework of the area. west-central tunisia has been studied by many authors who discussed the tectonic settings and geodynamic evolution of the different structures related to north africa tectonics (e.g. burollet, 1956; dlala, 1984; zargouni, 1985; martinez et al., 1990; ben ayed, 1993; el euchi, 1993, boukadi, 1994, chihi, 1995; rigane et al., 2010; zouaghi et al., 2011, 2013; harzali et al., 2019). previous stratigraphic and sedimentological studies have contributed to interpretations of cretaceous palaeogeography in west-central tunisia (fig. 3), which is considered to represent a large transitional zone between the platform to the south, and a deep trough to the north (e.g. bismuth et al., 1981, marie et al., 1984, zghal, 1994; benzarti, 2002; lazzez et al., 2008; ben fadhel et al., 2011; zouaghi et al., 2011). the main aim of this study is to characterize the reservoir properties of the aptian series in west-central tunisia, specifically the facies evolution from the southern to northern areas, based on the interpretation of the sedimentary succession from g eo lo gi a c ro at ic a geologia croatica 73/160 the aptian extensional tectonic phase has been coupled with the rising of triassic evaporites such as salt domes, salt rollers, and salt walls (zouaghi et al., 2011, 2013). this halokinetic rise is mostly highlighted at the intersection of two or more master faults, and is related to tectonic reactivation associated with stress changes (zouaghi et al., 2011). the aptian tectonic movements in west-central tunisia were controlled by the tethyan tectonic evolution (e.g. dercourt et al., 1985; soyer, & tricart, 1987; zouaghi et al., 2013). these regional extensional events, fossilized in the north african plate, seem to be related to the south atlantic opening (e.g. maritinez et al., 1991; barrier et al., 1993; piqué et al., 1998; bédir et al., 2001; bouaziz et al., 2002; zouaghi et al., 2005, 2011; jaillard et al., 2013). figure 1. a structural map of tunisia (etap, 2000) showing the main geological features, with the location of the study area in west-central tunisia. figure 2. a palaeogeographic map of the tunisian aptian showing the main depositional domain from the saharan platform in the south to the subsiding trough to the north (zghal & arnaud-vanneau, 2005). figure 3. a lithostratigraphic chart of the tunisian early cretaceous simplified from various previous studies (e.g. m’rabet et al., 1995; ben youssef, 1999). g eologia c roatica lazzez et al.: csedimentary and structural setting of the aptian reservoir deposits in the kasserine area, west-central tunisia 61 3. aptian palaeogeography in west-central tunisia the outcropping aptian lithofacies covering wide areas of the tunisian realm, reflect distinct depositional settings (fig. 2), ranging from continental deposits in the south to marine facies northward (e.g. bismuth, 1973; tlatli, 1980; boltenhagen, 1981; m’rabet, 1981; marie et al., 1984; zghal, 1994; benzarti, 2002; lehmann et al., 2009). these successions are essentially controlled, in addition to sea-level changes, by the geodynamics of the western tethys realm (e.g. dercourt et al., 1985; ricou, 1994; bouaziz et al., 2002; lazzez et al., 2008; zouaghi et al., 2011, 2013). during the aptian, the tunisian realm was subdivided into three distinct provinces, respectively named southern, central and northern palaeogeographic domains (fig. 2). southern continental to lagoonal environments prevail over large areas of the saharan platform. farther north, these environments transition into a shallow marine platform, extending over a larger area in both onshore and offshore domains. it is characterized by mixed inner shelf facies which consist mainly of carbonate deposits with sandstone and shale intercalations (figs. 2 and 3). this facies indicates open marine conditions, marked by bioclastic limestones with marl intercalations and reef deposits. a high block named kairouan island, located in the eastern part is characterized by post aptian erosion (fig. 2). the northern part of tunisia was dominated by subsiding zones with predominantly pelagic deposition marked by claystones and marlstones with intercalated turbidites (e.g. zghal, 1994; zghal & arnaudvanneau, 2005). 4. stratigraphy the aptian serdj formation was described in the stratotype section at the serdj anticline (burollet, 1956). several biostratigraphic frameworks dealing with the age of serdj formation have been established and widely discussed (e.g. bismuth, 1973; tlatli, 1980; m’rabet, 1981; zghal, 1994). in west-central tunisia, the aptian successions display lateral thickness and facies variation, and are associated with major unconformities of erosional or non-depositional events. previous hydrocarbon exploration on the serdj formation have proven it to be productive as demonstrated by numerous oil and gas discoveries that have been made in the douleb, semmama, and tamesmida fields. in central tunisia, the serdj formation, which overlies sands of the barremian sidi aich formation, consists mainly of carbonates including some sandstone and shale beds (fig. 3). the limestone beds are oolitic and/or bioclastic. they display mudstone, wackstone and packstone textures and contain orbitolinids, crinoids, bryozoans, gastropods, cephalopods, pelecypods, green and red algae with locally abundant rudists and corals (e.g. bismuth, 1973; m’rabet et al., 1979; burollet et al., 1983; zghal, 1994; benzarti, 2002; ben ferjani et al., 2006; zouaghi, 2008; lehmann et al., 2009; heldt et al., 2010; figure 4. e-w lithostratigraphic correlation of the aptian reservoir formation from outcrops and wells. g eo lo gi a c ro at ic a geologia croatica 73/162 zouaghi et al., 2011). locally, to the north of the study area, rudist and coral carbonate reefs are found in the serdj anticline of central tunisia (tlatli, 1980). the dolomite beds are generally massive and contain bioclastic debris including recrystallized or dissolved orbitolinids and rudists (e.g. bismuth et al., 1981, m’rabet et al., 1979; zouaghi, 2011). the serdj formation was subdivided into three different members (figs. 4 and 5); the lower bioclastic-oolitic limestones and dolomites, partly with sand and clay layers, mark (bedoulian-early gargasian). the middle member (gargasian-early clansayesi an) consists mainly of dolomite beds, associated with limestone and clastic intercalations. the upper member (clansayesian) is represented by bioclastic limestone and dolomite. the serdj formation is overlain unconformably, across almost the entire region, by deposits of the upper albian fahdene formation. the transitional horizon between the two formations is either missing, indicated by hardground surfaces, or consists of conglomeratic beds, which likely suggest sedimentary hiatuses (ghanmi et al., 2017; harzali et al., 2019). in the far northwestern tunisia, green marls alternating with limestone and sandstone beds attributed to the hamaima formation (e.g. chihaoui et al., 2010; jaillard et al., 2013) outline the transition. 5. basin deposition during aptian time, relatively varied and continuous sedimentation occurred throughout central tunisia. the tunisian trough and the gafsa basin were subsiding domains, separated by the central tunisian platform. this high zone is marked by the kairouan island, characterized by unconformities in aptian strata on structures outcropping around the north part of the north– south lineament (zouaghi et al., 2011). aptian sedimentation was controlled by extensional and/or transtensional deformation leading to multiscale fracturing in structural blocks associated with salt movements (zouaghi et al., 2005; rigane et al., 2010). 5.1. sedimentary evolution the aptian serdj formation is considered to be the main target of exploration in west-central tunisia. this interval, containing several reservoir layers, shows lateral variation in thickness and facies. the stratigraphic correlation of the serdj formation, including data from deep wells and outcrops of the el hamra, mrhi la and hallouf structures, provided important details about the platform structure and allowed interpretation of the reservoir stratigraphic framework. three members were characterized, demonstrating facies evolution from the inner shelf to open marine depositional environments (fig. 4). 5.1.1. lower member the lower member, consisting of oolitic limestone beds and sandstone intercalations, is about 130 m thick in the el hamra anticline and the w1 well. the member thickness increases progressively eastwards reaching 180 m in the mrhila outcrops, 105 m in w2 well and 200 m in the hallouf anticline outcrops. the latefigure 5. n-s subsurface lithostratigraphic correlation of the aptian deposits (inner platform depositsbasin facies). lazzez et al.: csedimentary and structural setting of the aptian reservoir deposits in the kasserine area, west-central tunisia 63 g eologia c roatica ral stratigraphic equivalent of this member shows significant detrital intercalations to the east. 5.1.2. middle member the middle member is about 100 m thick in the el hamra, mrhi la and hallouf anticline outcrops. it consists mostly of dolomite beds, including limestone and shale intercalations in the el hamra anticline and the w1 well, located in the western part of the study area. to the east, the middle member shows thick detrital intercalations that can be recognized in the mrhila, halouf anticlines and the w2 well. 5.1.3. upper member the upper member is composed of oolitic and bioclastic carbona te layers outcropping in the el hamra anticline and the w1 well. this member is missing in the eastern part of the study area. 5.2. depositional environment the serdj formation facies indicates shallow depositional marine conditions and characterized by a wide spatial extent in central tunisia. the depositional environment grades laterally southwards to inner shelf deposition characterized by mixed carbonate, evaporite and some siliciclastic intercalations of the orbata formation. to the north and the northeast, the aptian successions correspond to an open marine carbonate shelf depositional environment that passes laterally into deep marine shale basin, the m’cherga formation. the facies evolution of the aptian reservoir indicates the presence of subsiding structures westward of the study area with thick deposition, and high zones eastward represented by kairouan island. to the north, the aptian successions reflect a deep basin depositional environment (fig. 5), represented by alternating limestone and marl layers (m’cherga formation) and some figure 6. lithofacies and sedimentary environments of aptian deposits in the study area. g eo lo gi a c ro at ic a geologia croatica 73/164 sandstone beds (the hamaima formation). the zone, separating the deep basin from the platform, displays horst and graben architecture linked to extensional tectonics, halokinesis and associated sea-level fall (zouaghi et al., 2011). it displays a transitional depositional system characterized by carbonate sedimentation coeval with increased detrital influx (heldt et al., 2010). the aptian basin configuration inherited from extensional phases and halokinesis dictated the sedimentary pattern, diagenetic processes, facies distribution and sequence geometries in west central tunisia, and as a consequence, controlled the mechanisms of trap development. we distinguish three areas that reveal proven reservoirs (fig. 6): the first area, marked by dolomite reservoir facies, is considered to be the most productive domain. the second area is characterized by carbonate reef and para-reef facies. detrital deposits characterize the third zone located in the north-south axis. the aptian serdj formation consists of bioclastic and oolitic carbonates that are affected by diagenetic processes that are active in the eogenetic zone and associated with phreatic, meteoric and vadose waters, resulting in local karstification and dolomitization (e.g. tlatli, 1980; heldt et al., 2010). the associated textures mostly composed of mudstone, wackstone and packstone mainly containing foraminifera, and cephalopods, indicate prevailing mid and outer ramp depositional environments in westcentral tunisia (fig. 7). 6. reservoir aspects tunisia has several proven and potential reservoirs and source rocks. in central tunisia, the reservoirs are highly heterogeneous, mainly carbonate and secondary sandstone of jurassic and cretaceous age. the formation of an aptian reservoir is associated with the uplift of reef carbonates of a barrier reef platform. the reservoir rocks are characterized by secondary porosity resulting from dissolution and karstification associated with emersion. 6.1. reservoir structures the aptian serdj carbonates are proven oil-producing reservoirs in central tunisia, with an effective porosity ranging from 7 to 25% in the dolomite and around 16% in the limestone beds. permeability ranges from 30 to 1000 millidarcy (md). the presence of fractures locally enlarged by karstification also enhances both porosity and permeability (e.g. ouahchi et al., 1998; zouaghi, 2008; ben brahim et al., 2012). this carbonate reservoir is regionally well sealed by the albian fahdene shales, which contain mature source rocks (e.g. saidi & belayouni, table 1. petrophysical parameters (vsh, sw and ø) in wells w4 and w6 showing levels of oil interest. (vshgr volume of shale by gr; phid porosity by density; sw water saturation; sh hydrocarbon saturation. the sh and sw identified by archie). well total depth (m) net pay (m) vshgr (%) phid (%) sw (%) sh (%) w4 278 10.5 25.11 10.2 20.32 79.68 w6 304 12 8.15 7.63 29.95 70.05 figure 7. 3-d block diagram showing the lateral evolution of aptian deposits from southern to northern tunisia. g eologia c roatica lazzez et al.: csedimentary and structural setting of the aptian reservoir deposits in the kasserine area, west-central tunisia 65 1994; ben ferjani et al., 2006; ben fadhel et al., 2011, 2014). the reservoir drainage is facilitated by the thickening and collapse of the albian source rock. in this case, hydrocarbons have lateral trending migration related to tectonic events that caused formation of nw-trending grabens and horsts. 6.2. well log study analysis of log data from two wells (w4 and w6, fig. 8) has yielded petro-physical characteristics summarized in table 1. it was postulated that the w6 well reservoir has a larger effective thickness with good porosity, while the effective thickness and porosity are reduced in the w4 well reservoir. northward of the study area, the w5 well reservoir has yielded poor petro-physical properties, showing low matrix porosity (less than 4%) and a high gamma ray shale volume (90%). these reservoir parameters indicate a deep depositional environment that prevailed during the aptian (zghal & arnaud, 2005). these results mean that the petro-physical properties increase when approaching the dolo mitic zone where the petroleum system is proven. the low porosity and permeability, the limited and non-homogeneous fracture distribution, and the complex storage space, together result in uncertainties around the effectiveness of evaluating tight carbonate reservoirs. the well tests produced only water, a failure that was probably related to late tectonic deformations. regarding the difference between the test result and hydrocarbon saturation provided by petrophysical evaluation, the archie equation seems to be inadequate for the tight dolomite in relation to with unavailable result agreed by low water saturation (sh up to 70% in w6, table 1). 7. conclusions in west-central tunisia, aptian sedimentary evolution is largely controlled by structures inherited from extensional halokinesis phases associated with the opening of the tethys ocean. during the aptian, west-central tunisia was demarcated to the north by a deep basin, the carbonate platform and an uplifted area, (the so called “kairouan island”) in the center, and the saharian platform to the south. in fact, the subsurface cuttings from wells, situated to the north of the study area, reveal a marine depositional environment that prevailed during the aptian. the subsurface study is in harmony with the palaeogeographic interpretations mentioned in previous studies in this area, indicating that during the aptian, open marine sedimentation was restricted to the northern part of the study area (nw of tunisia) where its lateral equivalent is represented by the upper part of the m’cherga formation together with the base of the fahdene formation. in west-central tunisia, the aptian serdj formation, which is a proven productive reservoir in the douleb, semmama and tamesmida fields, consists mostly of carbonates including oolitic and/or bioclastic limestone and dolomite beds, associated with some sandstone and shale intercalations. the carbonate textures vary from mudstone, wackstone to packstone, containing foraminifera, and cephalopods indicating midand outer-ramp depositional environments. we conclude that tectonic phases and salt movement closely control the distribution of the studied aptian serdj formation reservoir. extensional phases have induced the development of figure 8. seismic sections showing the anticline structure through the w4 well. g eo lo gi a c ro at ic a geologia croatica 73/166 the horst-and-graben architecture. the high-energy oolitic carbonate platform was developed on the horst blocks. the latter are bounded by faults providing dolomitization and improving the porosity in carbonate beds. an ascending salt episode has been influential in the reservoir distribution and therefore, providing locally siliciclastic sediments. the well log analysis of the aptian reservoir using data from two wells, shows that the petrophysical qualities increase when approaching the main productive dolomite facies zone. the failure of these wells is probably related to a timing problem (young or late structuring). this work provides a systematic approach to evaluate exploration opportunities in lateral facies distributions according to basin layout, as well as raising new important questions and/or suspicions for directing further research for deeper targets around salt domes for other areas in the northern onshore and offshore parts of tunisia. acknowledgement the authors are appreciative to the etap, fst, and certe for their scientific cooperation and help. references barrier, e., bouaziz, s., angelier, j., creuzot, g., ouali, j. & tricart, p. (1993): mesozoic paleostress evolution in the saharian platform (southern tunisia).– geodinamica acta, 6, 39–57. doi: 10.1080/09853111.1993.11105238 bédir, m., boukadi, n., tlig, s., ben timzal, f., zitouni, l., alouani, r., slimane, f., bobier, c. & zargouni, f. (2001): subsurface mesozoic basins in the central atlas of tunisia, tectonics, sequence deposit distribution and hydrocarbon potential.– american association of petroleum geologists bulletin, 85, 885–907. ben ayed, n. (1993): evolution tectonique de l’avant-pays de la chaîne alpine de tunisie du début du mésozoïque à l’actuel.– annales des mines et de la géologie, tunisie, 32, 296 p. ben brahim, g., brahim, n. & turki, f. (2012) : tectonic evolution and hydrocarbon potential of the aptian series in the mahdia offshore area, tunisia.– journal of petroleum science and engineering, 90, 175–190. doi: 10.1016/j.petrol.2012.04.013 ben fadhel, m.., layeb, m., hedfi, a. & youssef, m.b. (2011): albian oceanic anoxic events in northern tunisia: biostratigraphic and geochemical insights.– cretaceous research, 32/6, 685–699. doi: 10.1016/j.cretres.2011.04.004 ben ferjani, a., burollet, p.f. & mejri, f. (2006): petroleum geology of tunisia. mémoire etap n°22, tunis, 233 p. ben youssef, m. (1999): stratigraphie génétique du crétacé de tunisie: micropaléontologie, stratigraphie séquentielle et géodynamique des bassins de la marge sud et péri-téthysienne.– thesis, doctorat d’etat, université tunis ii, tunisia, 402 p. benzarti, r. (2002): synthèse biostratigraphique du permis jelma.– rapport inédit, serept (société de recherche et d’exploitation des petroles en tunisie), tunisia, gn3833, 37 p. bismuth, h. (1973): réflexions stratigraphiques sur l’albo-aptien dans la région des djebels douleb et semmama et son environnement (tunisie centre-nord).– in: solignac m. (editor). livre jubilaire, annales des mines et de géologie, tunisie, n°26, 179–212. bismuth, h., boltenhagen, c., donze, p., lefèvre, j. & saint marc, p. (1981): le crétacé moyen et supérieur du jebel semmama (tunisie du centrenord), évolution sédimentologique et microstratigraphique.– cretaceous research, 3, 171–186. boltenhagen, c. (1981): les séquences de sédimentation du crétacé moyen en tunisie centrale.– actes du premier congrès des sciences de la terre, tunis, 55–71. bouaziz, s., barrier, e., soussi, m., turki, m.m. & zouari, h. (2002): tectonic evolution of the northern african margin in tunisia from paleostress data and sedimentary record.– tectonophysics, 357, 227–253. doi: 10.1016/s00401951(02)00370-0 boukadi, n. (1994): structuration de l’atlas de tunisie: signification géométrique et cinématique des noeuds et des zones d’interférences structurales au contact de grands couloirs tectoniques.– thesis, doctorat d’etat, fst, université de tunis ii, tunisia, 249 p. burollet, p.f. (1956): contribution à l’étude stratigraphique de la tunisie centrale.– annales des mines et de la géologie, tunisie, n°18, 342 p. burollet, p.f., memmi, l. & m’rabet, a. (1983): le crétacé inférieur de tunisie. aperçu stratigraphique et sédimentologique.– zitteliana, 10, munchen, 255–264. chihaoui, a., jaillard, e., latil, j.l., zghal, i., susperregui, a.s., touir, j. & ouali, j. (2010): stratigraphy of the hameima and lower fahdene formations in the tadjerouine area (northern tunisia).– journal of african earth sciences, 58/2, 387–399. doi: 10.1016/j.jafrearsci.2010.02.008 chihi, l. (1995): les fossés néogènes à quaternaires de la tunisie et de la mer pélagienne: leur signification dans le cadre géodynamique de la méditerranée centrale.– thesis, doctorat d’etat, fst, université de tunis ii, tunisia, 324 p. chihi, l. & ben ayed, n. (1991): le rôle de la fracturation précoce sur la distribution des structures récentes le long du décrochement de kasserine.– annales tectonicae, 5/1. 64–73. dercourt, j., zonenshain, l.p., ricou, l.e., kazmin, v.g., le pichon, x., knipper, a.l., grandjacquet, c., sborshchikov, i.m., buillin, j., sorokhtin, o., geyssant, j., lepvrier, m., biju duval, b., sibuet, j.c., savostin, j.c., westphal, m. & lauer, j.p. (1985): présentation de neuf cartes paléogéographiques au 1/20.000.000 s’étendant de l’atlantique au pamir pour la période du lias à l’actuel.– bulletin de la société géologique de france 8, 637–652. dlala, m. (1984): étude tectonique et microtectonique de la région de kasserine (tunisie centrale).– thesis, doctorat 3ème cycle, cnrs, université montpellier, france, 138 p. el euchi, h. (1993): la tunisie du centre-ouest de l’aptien à l’actuel: tectonique coulissante, dynamique sédimentaire associée et essai de caractérisation des séquences de dépôt.– thesis, doctorat 3ème cycle, université tunis ii, tunisia, 263 p. etap-entreprise tunisienne d’activités pétrolières (2000): tunisia open acreage, tunis, tunisia.– imprimeries réunies groupe cérès conseil ddb, 77 p. ghanmi, m. a., barhoumi, a., ghanmi, m., & zargouni, f. (2017): aptianalbian boundary in central southern atlas of tunisia: new tectono-sedimentary facts. journal of african earth sciences, 132, 27–36. doi: 10.1016/j. jafrearsci.2017.04.030 harzali, m., troudi, h., godet, a. & ouali, j. (2019): seismic stratigraphy and hydrocarbon prospectivity of the aptian–albian succession along the oued bahloul basin, central ouest tunisia.– journal of iberian geology. doi: 10.1007/ s41513-019-00100-4 heldt, m., lehmann, j., bachmann, m., negra, h. & kuss, j. (2010): increased terrigenous influx but no drowning: palaeoenvironmental evolution of the tunisian carbonate platform margin during the late aptian.– sedimentology, 57/2, 695–719. doi: 10.1111/j.1365-3091.2009.01115.x jaillard, e., dumont, t., ouali, j., bouillin, j.p., chihaoui, a., latil, j.l., arnaud, h., arnaud-vanneau, a. & zghal, i. (2013): the albian tectonic “crisis” in central tunisia: nature and chronology of the deformations.– journal of african earth sciences, 85, 75–86. doi: 10.1016/j. jafrearsci.2013.04.008 lazzez, m., zouaghi, t. & ben youssef, m. (2008): austrian phase on the northern african margin inferred from sequence stratigraphy and sedimentary records in southern tunisia (chotts and djeffara areas).– comptes rendus geoscience, 340, 543–552. doi: 10.1016/j.crte.2008.05.005 lehmann, j., heldt, m., bachmann, m. & negra, m.e.h. (2009): aptian (lower cretaceous) biostratigraphy and cephalopods from north central tunisia.– cretaceous research 30/4, 895–910. doi: 10.1016/j.cretres.2009.02.002 marie, j., trouvé, p., desforges, g. & dufaure, p. (1984): nouveaux éléments de paléogéographie du crétacé de tunisie.– compagnie française de pétroles, mémoire, 19, 7–37. martinez, c., turki, m.m. & truillet, r. (1990): la signification des plis d’orientation méridienne dans l’atlas tunisien centro-méridional.– bulletin de la société géologique de france, 8, 843–852. masse, j.p. (1984): données nouvelles sur la stratigraphie de l’aptien carbonaté de tunisie centrale, conséquences paléogéographiques.– bulletin de la société géologique de france, 6, 1077–1086. m’rabet, a. (1981): stratigraphie, sédimentation et diagenèse carbonatée des séries du crétacé inférieur de tunisie centrale.– thesis, doctorat d’etat, université paris-sud, centre d’orsay, france, 540 p. m’rabet, a., dufaure, p. & burollet, p.f. (1979): nouvelles données biostratigraphiques, sédimentologiques et paléogéographiques sur l’aptien de tunisie central.– geobios, mémoire spécial, 3, 213–229. m’rabet, a., mejri, f., burollet, p.f., memmi, l. & chandoul, h. (1995): recueil des coupes types de tunisie.– entreprise tunisienne d’activités pétrolières (etap), mémoire 8b, 123 p. ouahchi, a., m’rabet, a., lazreg, j., messaoudi, f. & ouazaa, s. (1998): early structuring, paleo-emersion and porosity development: a key for exploration g eologia c roatica lazzez et al.: csedimentary and structural setting of the aptian reservoir deposits in the kasserine area, west-central tunisia 67 of the aptian serdj carbonate reservoir in tunisia.– proceedings of the 6th tunisian petroleum exploration and production conference, tunis, tunisia, 267–284. piqué, a., brahim, l.a., ouali, r.a., amrhar, m., charroud, m., gourmelen, c., laville, e., rekhiss, f. & tircart, p. (1998): evolution structurale des domaines atlasique du maghreb au méso-cénozoïque; le rôle des structures héritées dans la déformation du domaine atlasique de l’afrique du nord.– bulletin de la société géologique de france, 169, 797–810. ricou, l.e. (1994): tethys reconstructed: plates continental fragments and their boundaries since 260 ma from central america to south-eastern asia.– geodinamica acta, 7, 169–218. doi: 10.1080/09853111.1994.11105266 rigane, a., feki, m., gourmelen, c. & montacer, m. (2010): the « aptian crisis » of the south-tethyan margin: new tectonic data in tunisia.– journal of african earth sciences, 57, 360–366. doi: 10.1016/j.jafrearsci.2009.11.005 saïdi, m. & belayouni, h. (1994): etude géologique et géochimique des roches mères albo-vraconienne dans le domaine de la tunisie centro-septentrional. in: proceeding of the 4th petroleum exploration conference.– mémoire etap, 7, 91–116 soyer, c. & tricart, p. (1987): la crise aptienne en tunisie centrale, approche paléostructurale aux confins de l’atlas et de l’axe nord-sud.– comptes rendus de l’académie des sciences, tome 305, série ii, 301–305. tlatli, m. (1980): etude des calcaires de l’albo-aptien des jebels serdj et bellouta (tunisie centrale).– thesis, doctorat 3ème cycle, université d’aixen-provence, marseille, france, 917 p. zargouni, f. (1985): tectonique de l’atlas méridional de tunisie. evolution géométrique et cinématique des structures en zones de cisaillement.– thesis, doctorat d’etat, université louis pasteur, strasbourg, france, 296 p. zghal, i. (1994): etude microbiostratigraphique du crétacé inférieur de la tunisie du centre ouest.– thesis, doctorat 3ème cycle, université tunis ii, tunisia, 393 p. zghal, i. & arnaud-vanneau, a. (2005): the hameima formation. aptian– turonian events in central tunisia. field trip guidebook.– géologie alpine, sér. spéc., 5, 101–104. zouaghi, t. (2008): distribution des séquences de dépôt du crétacé (aptien-maastrichtien) en subsurface: déformation tectonique, halocinèse, évolution géodynamique (atlas central de tunisie).– ph.d. thesis, université tunis el manar, tunisia, 367 p. zouaghi, t., bédir, m., ayed-khaled, a., lazzez, m., soua, m., amri, a. & inoubli, m.h. (2013): autochthonous versus allochthonous upper triassic evaporates in the sbiba graben, central tunisia.– journal of structural geology, 52, 163–183. zouaghi, t., bédir, m. & inoubli, m.h. (2005): 2d seismic interpretation of strike-slip faulting, salt tectonics, and cretaceous unconformities, atlas mountains, central tunisia.– journal of african earth sciences, 43, 464–486. doi: 10.1016/j. jafrearsci.2005.09.010 zouaghi, t., ben youssef, m., ferhi, i., inoubli, m.h., gasmi, m. & bédir, m. (2011): analysis of cretaceous (aptian) strata in central tunisia, using 2d seismic data and well logs.– journal of african earth sciences, 61, 38–61. doi: 10.1016/j.jafrearsci.2011.05.002 2019 | 72 / special issue | 47–56 | 18 figs. | 2 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction in recent years, a large number of high dams, large reservoirs and pumped storage power stations, usually accompanied by underground powerhouses and other caverns, have been (and are) under construction in china. in these construction projects, extremely complex seepage fields develop, especially when complex geological conditions are encountered and/or drainage galleries with arrays of densely-spaced drainage holes are arranged. in general, the seepage flow in the vicinity of a high dam and an underground powerhouse are analyzed separately. however, after construction of a high dam and impoundment of the reservoir, a three-dimensional monolithic seepage field is formed in the dam, in the vicinity of the underground powerhouse and in the surrounding rock mass. this monolithic seepage field may be approximately regarded as the combination of free surface seepage flow, mainly in the dam body and the surrounding rock mass and seepage flow in the vicinity of galleries with arrays of densely-spaced drainage holes. the behaviour of the monolithic seepage field is directly related to the safe operation of the power station. hence, the accurate numerical analysis of the complex monolithic seepage field, e.g. by means of the finite element method (fem), is of great importance. seepage flow with a free surface is usually analyzed on the basis of a fixed finite element mesh as originally proposed by neuman (neuman, 1973), because in contrast to adaptive mesh methods, unfavourable distortions of finite elements are avoided. on the basis of the fixed mesh method, different numeric techniques have been proposed, such as the variable permeability method (bathe et al., 1979), the residual flow method (desai & li, 1983), the initial flow method (zhang et al., 1988), the virtual flux method (vfm) (zhu & su, 1991; zhu, 1997), the variational inequality method (jansen et al., 1988), the refined a new numerical method for the analysis of monolithic seepage problems with complex drainage systems in a groundwater recharge area for a hydropower station in china yan jun1, liu si-hong2,*,wei ying-qi1, jin song-li1, cai hong1 and xiao jian-zhang1 1 china institute of water resources and hydropower research, department of geotechnical engineering, state key laboratory of simulation and regulation of water cycle in river basin, no.20 chegongzhuang west rd, haidian, beijing 100048, china; (yanjunwuhan@163.com) 2 hohai university, college of water conservancy and hydropower engineering, nanjing 210098, china; (sihongliu@hhu.edu.cn) doi: 10.4154/gc.2019.24 abstract after construction of a dam impounding water in a reservoir, a monolithic seepage field develops in the surrounding rock mass. here, a new finite element method is proposed for determining the shape and characteristics of the 3d monolithic seepage field including the free surface, considering complex drainage systems consisting of densely-spaced drainage holes and drainage galleries. to this end, the previously proposed virtual flux method is improved by a refined numerical integration scheme and a regularized heaviside function for distinguishing the subregions below and above the free surface within a particular finite element. leakage and overflow drainage holes are modeled as internal boundaries. the proposed numerical method is verified by an academic example, for which the analytical solution is available. finally, the numerical simulation of the seepage field developing in the vicinity of a high dam and underground power house, constructed in the context of a hydropower plant project in china is used to show its application to a problem in engineering practice. gauss point method (wang & huang, 1997), the variational inequality method (zheng et al., 2005b) and related methods (shu et al., 2007; alt, 1980; wang, 1998; zheng et al., 2005a; borja & kishnani, 1991; gabriella et al., 2016; azusa et al., 2018). however, for determining the free surface with higher accuracy, most of the aforementioned numerical methods require a very fine discretization, especially in the vicinity of the free surface, which is computationally expensive for 3d problems in engineering practice. the fe analysis of seepage flow considering galleries with arrays of densely-spaced drainage holes involves two difficulties: one is the fe mesh generation of arrays of drainage holes with small diameters and dense spacing and the other is the determination of the free surface in the vicinity of the complex drainage system. to overcome these difficulties, either the equivalent permeability method or the direct method can be employed. in the equivalent permeability method, the drainage holes and the surrounding rock mass are homogenized as a complex medium with an equivalent anisotropic permeability (chen et al., 2004; jing et al., 2005; chen et al., 2010). an advantage of this method is the simple generation of the fe mesh. however, it is not easy to determine the equivalent permeability tensor for the finite elements affected by drainage holes, and thus the drainage facilities cannot be described precisely. in the direct method, the drainage holes are regarded as internal drainage boundaries of the seepage field, which are modeled by a semi-analytical approach (fipps et al., 1986) or a substructure technique (zhu & zhang, 1997; chen et al., 2008). the direct method allows considering drainage holes with a relatively high precision, but generation of the fe mesh is difficult and it is also computationally expensive. in this study, an improved virtual flux method (ivfm) for seepage flow with a free surface and a direct method for modeling article history: manuscript received april 11, 2019 revised manuscript accepted august 28, 2019 available online december 20, 2019 keywords: monolithic seepage problem, drainage system, free surface, finite element method g eo lo gi a c ro at ic a geologia croatica 72 / special issue48 seepage flow in regions with densely-spaced drainage holes is proposed. after validation of the method by a academic example, it was employed for determining the monolithic seepage field formed in the vicinity of a high dam and underground powerhouse, constructed in the context of a hydropower plant project in china. 2 methods 2.1. description of the free surface seepage problem figure 1. shows the free surface seepage flow through a dam body. the dam is characterized by the domain w = w1  w2, however, seepage flow is actually restricted to the domain w1 thus, the domain w1 can be referred to as the actual domain while the domain w2 can be denoted as the virtual domain. no seepage flow occurs through the free surface g3, which is the common boundary of domains w1 and w2. the total waterhead at a point in the domain w1 is defined as: h = x3 + hc (1) where x3 denotes the vertical coordinate, hc = p/gw the pressure water head, p the pore water pressure, and gw the unit weight of water. the seepage velocity in the domain w1 can be calculated by darcy’s law: v = –kh (2) where k is the permeability tensor and  represents the gradient operator. the seepage flow satisfies the continuity equation: v = 0 (3) according to figure 1. the following boundary conditions are prescribed: (1) the dirichlet type boundary condition i.e. the waterhead boundary condition h = h with h = h1 on g1 = bg and h = h2 on g1 = cd, (4) where g1 is the part of the boundary with the prescribed waterhead h. (2) the neumann type boundary condition i.e. the flux boundary condition qn = –nt v = q on g2 = ag+af+ef+bc (5) where n and qn are the outward unit normal vector to the corresponding part of the boundary and the respective prescribed flux in the direction normal to the boundary, respectively, and g2 is the part of the boundary with the prescribed flux. (3) the cauchy type boundary conditions qn = 0 and h = x3 (6) on the free surface g3 = eg. (4) the composite boundary conditions on the seepage surface g4 qn ≥ 0 and h = x3 on g4 = de (7) 2.2. fe formulation of free surface seepage problems 2.2.1. fe discretization of free surface seepage problems for the free surface seepage problem shown in fig. 1, the domain w = w1  w2 is divided into n finite elements. within a particular finite element e, the total water head h is approximated by the vector of nodal water head values he and a vector of shape functions ne as h = (ne)t he (mao et al., 1999). the corresponding pressure water head hc is then computed from eq. (1). hc is positive within w1 and negative within w2. hence, w1 is denoted as the actual domain of seepage flow, whereas w2 is denoted as the virtual domain. accordingly, finite elements in the domain w1 are denoted as actual finite elements, whereas finite elements in the domain w2 are denoted as virtual elements. finite elements passed through by the free surface, which are characterized partly by hc > 0 and partly by hc < 0, are referred to as transition elements. substituting eq. (2) into eq. (3), gives the governing differential equation. discretization of the weak form of the governing differential equation yields the fe balance equation in the seepage domain w1 k1h = q1 (8) in (8) k1 denotes the global permeability matrix for the domain w1, obtained by assembling the element permeability matrices ke located in domain w1, h denotes the vector of the unknown nodal values of the total waterhead, and q1 represents the vector of nodal fluxes in w1 computed from prescribed values of the waterhead on g1 and g1. as the domain w1 and the seepage surface g4 are unknown in advance, the solution of the free surface seepage problem cannot be obtained directly from eq.(8). hence, an iterative solution scheme is proposed. it is characterized by improving the virtual flux method (vfm) (zhu & su, 1991; zhu, 1997) by a refined gauss point method combined with a regularized heaviside function (chen et al., 2008) for determining the free surface. 2.2.2. improved virtual flux method (ivfm) as the domain w1 is unknown in advance, eq. (8) is replaced by the respective fe balance equation for domain w kh = q (9) where k represents the global permeability matrix for domain w and q the corresponding flux vector computed from the prescribed values of the waterhead. the basic idea of the vfm is to determine the virtual domain w2 in an iterative manner and to gradually deduct the virtual flux contribution of the nodes in domain w2 until there is no flux across the interface between w1 and w2. the boundary conditions on the free surface g3 in eq. (6) are then met automatically and the free surface can be identified by interpolating the water head according to the requirement of h = x3 within the transition elements. figure 1. illustration of unconfined seepage through a dam body. g eologia c roatica yan jun et al.: a new numerical method for the analysis of monolithic seepage problems with complex drainage systems in a groundwater recharge area ... 49 similarly, in eq. (8), the fe balance equation for the virtual domain w2 is given as: k2h = q2 (10) where k2 is the global permeability matrix for the domain w2 and q2 denotes the corresponding nodal flux vector. from eq. (8), eq. (9) and eq. (10) it then follows that k1 = k – k2, q1 = q – q2 (11) substituting eq. (11) into eq. (8) yields the fe balance equation within the framework of the ivfm: kh = q – q2 + k2h (12) making use of eq. (9) and eq. (12), the iterative form of the ivfm can be written as 1 0 1−  =  ≥ i i i i i i i for i for i2 2 kh = q kh = q q + k h (13) with i denoting the iteration step; hi and qi are the nodal waterhead and the nodal flux vectors for the domain w at iteration step i, whereas k2 and q2 denote the permeability matrix and the flux vector for the virtual domain w2 at the respective iteration step. in the ivfm, the solution of the free surface seepage problem is obtained by gradually modifying domain w2 and, hence, q2 and k2 in each iteration step. based on the first estimate of the waterhead, computed from h0 in the first part of the eq. (13), an initial estimate of the virtual domain w2 and, hence initial estimates of k2 and q2, denoted as k2 and q2 in the second part of eq. (13), is determined. subsequently, the second part of eq. (13) is solved for hi, yielding an improved estimate of the waterhead and, consequently, an improved estimate of the domain w2. the iteration is continued until the convergence criterion for the nodal waterhead vector 1 1 1 1 ε − − − < i i ri h h h (14) is met, where er denotes an error threshold value. q2 represents the nodal flux vector in domain w2, which is contributed by the prescribed boundary values of the waterhead as well as by the prescribed boundary values of the flux. hence, in general, non-zero items in q2 are only computed for transition elements with prescribed waterheads on g1 and g4. since the contribution from the latter is small compared to qi, qi 2 could be neglected. since the virtual domain consists of virtual elements and fractions of transition elements, k2 is obtained by assembling the permeability matrices ke of both the virtual elements and the respective virtual fractions of the transition elements. whereas calculating ke for the virtual elements is straightforward, it is not for the virtual fractions of the transition elements. 2.2.3 permeability matrix ke of a transition element the permeability matrix ke of a particular finite element e is obtained by gauss-legendre integration, yielding for a three-dimensional iso-parametric finite element ( , , )ξ η ζ= ∑ ∑ ∑e e n n ng g g i j m i j m i j m ww wk f (15) where ng is the number of integration points in each direction and wi, wj and wm and wm are the respective integration weights; ( , , ) [( ) det ]ξ η ζ =e e t e e e i j mf b k b j is the integrand, evaluated at the integration point ( , , )i j mξ η ζ , with be as the geometric matrix, containing the derivatives of the shape functions and detje as the determinant of the jacobian matrix. to compute the permeability matrix ke for a transition element, a refined gauss point method (wang & huang, 1997) combined with a regularized heaviside function (chen et al., 2008) is implemented in the framework of the ivfm. (1) the refined gauss point method a gauss quadrature point in a transition element is either assigned to the virtual domain if its waterhead hc is negative or to the actual domain if hc is positive. for determining the contribution of the element permeability matrix ke to the global permeability matrix k2 for a transition element, the integration of ke is then carried out only for the gauss points within the virtual domain. the accuracy of calculating ke can be improved by increasing the number of gauss points (shu et al., 2007), as shown in fig. 2. in the developed code, up to 7 gauss points in each direction may be used for a 3d iso-parametric finite element. the increase of the number of gauss points has an effect similar to refining the mesh in the vicinity of the free surface. however, depending on the computed value of the waterhead hc at a particular gauss point, the subregion of a finite element associated with this gauss point is still entirely assigned to either the actual domain or the virtual domain. this shortcoming is shown for example in fig. 3. if, for example, the free surface passes through the region between gauss point i and node 1, the actual domain in the shaded part 1 would be wrongly treated as a virtual domain due to negative values of hc at all gauss points of this element. similarly, the virtual domain in the shaded part 2 would be wrongly treated as an actual domain due to positive values of hc at all gauss points of this element. (2) the regularized heaviside function to overcome the aforementioned shortcoming, a regularized heaviside function (su et al., 1999; zhang & wu, 2005) figure 2. illustration of the refined gaussian points method in a 2d isoparametric element. figure 3. illustration of the defects of the refined gaussian points method. g eo lo gi a c ro at ic a geologia croatica 72 / special issue50 2 1 1 2 2 1 1 1 if ( ) if 0 if c c c c c h hh h h h ε ε ε ε ε ε ε ε  ≥  −= ≤ < −  < (16) is introduced with the parameters e1 < 0 and e2 > 0 (fig. 4(a)). for a 2d finite element fig.4(b) illustrates the application of the regularized heaviside function for the two cases shown in fig. 3 and the definition of the regularization parameters e1 and e2. by implementing the above regularized heaviside function, the permeability matrix ek of the virtual domain in a transition element is computed as (1 ( ( , , ))) ( , , )ε ξ η ζ ξ η ζ= −∑ ∑ ∑e e e c n n ng g g i j m i j m i j m i j m ww w h hk f (17) where ( , , )e c i j mh ξ η ζ is the water head at the gauss point ( , , )i j mξ η ζ . 2.2.4. determination of the seepage surface as expressed by eq. (7), on the seepage surface g4 the flux is non-negative and the waterhead is equal to the vertical coordinate x3 of the respective point on the boundary. according to the equivalent nodal flux method proposed (zhu & zhang, 1997), the total flux on the seepage surface is equivalent to the sum of the nodal values of the flux on the respective surface. thus, the boundary condition for the seepage surface qn ≥ 0 is replaced by the condition qn ≥ 0 for the node i, located on the seepage surface. since the seepage surface g4 = de in fig. 1 is unknown in advance, it is determined in an iterative manner. in the first iteration step, it is assumed that all nodes on the possible seepage surface df in fig. 1 satisfy the water head requirement h = x3. then the fluxes at the nodes along df are calculated. if, for a particular node qn ≥ 0 holds, then the respective node is considered to belong to the seepage surface g4 in the next iteration step. 2.3. consideration of densely spaced drainage holes drainage holes in hydraulic or geotechnical engineering are commonly classified into leakage drainage holes and overflow drainage holes according to the respective seepage behaviour. figure 5. shows the drainage galleries and arrays of drainage holes arranged at the upstream side of an underground powerhouse. drainage holes of array 1 are drilled in upward direction from the roof of drainage gallery 1, while drainage holes of array 2 and array 3 are drilled between the upper gallery and the lower gallery. in these drainage holes, shown in fig. 6(a), the water leakage from the hole walls is discharged into the lower galleries. in this study, they are classified as leakage drainage holes satisfying the boundary conditions qn = 0 and h < x3 on g = ab + a'b' (18) qn ≥ 0 and h < x3 on g = bc + b'c' (19) a leakage drainage hole is inactive if it is entirely located above the free seepage surface. in this study, drainage galleries are also treated as leakage drainage holes. in fig. 5, the drainage holes of array 4 are drilled in a downward direction from the bottom of the lowest gallery and they are classified as overflow drainage holes since water flows freely from the top of these holes when the holes are filled with water. in this case, shown in fig.6(b), the waterhead for nodes located on the hole wall is equal to that of the nodes at the orifice of the hole, i.e. h = h' on g = ab + a'b' + b'b' (20) where h' represents the waterhead at node a or a'. the power of the modern computer allows the direct modelling of densely-spaced drainage holes of small diameter. in this study, the wall of each drainage hole is considered as an internal drainage boundary and is integrated into the overall numerical model for determining the free seepage surface. in the numerical simulation procedure, all the drainage holes are treated as bounfigure 4. the continuous penalized heaviside function and the two penalty parameters. figure 5. drainage galleries and holes arranged in the upstream area of an underground powerhouse under construction in china. figure 6. seepage behaviours in two kinds of drainage holes (a) leakage drainage hole (b) overflow drainage hole. g eologia c roatica yan jun et al.: a new numerical method for the analysis of monolithic seepage problems with complex drainage systems in a groundwater recharge area ... 51 dary conditions. hence, the related iteration is the same as the seepage surface by the ivfm. as a result, the overall seepage field and the seepage field in the vicinity of densely-spaced drainage holes are computed simultaneously. for reasonable representation of well drainage holes with small diameters in a numerical model, a fine discretization is required in the vicinity of such drainage holes, whereas for the overall seepage field a considerably coarser discretization is employed. hence, special attention has to be paid to the smooth transition between domains with fine and coarse meshing. in the present context, as shown in fig. 7, a substructure technique is implemented for generating fe meshes with densely-spaced drainage holes. the basic idea is to discretize the domain under consideration disregarding the drainage holes. finite elements containing drainage holes serve as super-elements, which are subdivided further radially in the direction of the drainage holes into two or more layers of sub elements. the substructure technique allows eliminating nodal unknowns in the interior of the super-elements. the number of the drainage holes embedded in a super-element is determined from the size of the super-element and the spacing between two drainage holes. figure 8. shows the planar graphs of various subdivisions in one super-element and fig. 8 (a), (b), (c), (d), and (e) shows one hole two layers of subelements, one hole three layers, one hole four layers, two holes four layers, and three holes four layers respectively. in this direct simulation method, the operation of each drainage hole is controlled as follows. assume that qt and qb denote the flux at the top and the bottom nodes of a drainage hole, respectively. a leakage drainage hole is inactive, if qb is negative, i.e. the drainage hole is located in the virtual domain above the free surface. otherwise, the leakage drainage hole is active. an overflow drainage hole is only active if it is located entirely in the actual domain below the free surface, characterized by a positive value of qt. the surface of an active leakage drainage hole satisfies the boundary conditions prescribed by eq. (18) and eq. (19), and the seepage surface is determined using the method presented in section 3.3. inactive leakage drainage holes are ignored. generally, the boundary conditions of drainage galleries or tunnels are similar to those of leakage drainage holes. thus, drainage galleries or tunnels are treated like leakage drainage holes. the surface of an active overflow drainage hole satisfies the boundary condition prescribed by eq. (20). the waterhead at the nodes of the surface is usually equal to the vertical coordinate of the top node of the hole. if the overflow drainage hole is inactive, then the whole boundary is assumed to be impermeable. whether a drainage hole is active or inactive is determined in the course of the iterative solution procedure for the seepage surface, described in section 3.2. at the beginning of the first iteration step all drainage holes are assumed to be in the active state. based on the results of the current iteration step, the fluxes qb for leakage drainage holes and the fluxes qt for overflow drainage holes are computed, then the states of the drainage holes are updated accordingly. subsequently, the boundary conditions of the drainage holes are adapted appropriately for the next iteration step. the iteration will be terminated, if the states of all drainage holes do not change in two adjacent iteration steps and if the convergence criterion (14) for the nodal waterhead vector is met. 3. results 3.1. verification the analytical solution for the free seepage surface in a homogeneous dam of rectangular shape is selected for verifying the ivfm. as shown in fig. 9, the width and height of the dam were figure 7. construction of a drainage substructure. figure 8. planar graphs of various subdivisions in one super-element (a) one hole two layers of sub-elements (b) one hole three layers (c) one hole four layers (d) two holes four layers and (e) three holes four layers. figure 9. a homogeneous dam of rectangular shape with drainage gallery and holes. g eo lo gi a c ro at ic a geologia croatica 72 / special issue52 chosen as 10.0m and 12.0m, respectively. the prescribed waterheads at the upstream and downstream face are 10.0m and 2.0m, respectively. the foundation of the dam is considered as an impermeable boundary. the analytical solution of the free seepage surface is given (zhou et al., 1996) as: 1 1/2(100 8 )h x= − (21) a regular fe-mesh, consisting of quadrilateral finite elements with dimensions of 0.5m×0.5m, is used for discretizing the dam body. figure 10. shows the computed location of the seepage point at the downstream face, employing an increasing number of gauss points for the numerical integration for consistently refined fe-meshes. it confirms that the numerical solution gradually approaches the analytical solution with an increasing number of gauss points. figure 11. contains a comparison of the analytical solution for the free surface, obtained from eq. (21), with numerical solutions computed on the basis of the virtual flux method (vfm) (zhu, 1991) and the present ivfm. the numerical solution by means of the vfm agrees well with the analytical solution, the ivfm allows even better reproduction of the analytical solution. hence, the proposed ivfm can be employed for analyzing free surface seepage problems with a greater accuracy. in a further step, a drainage gallery, characterized by a cross section of 1.0m×1.0m, a leakage drainage hole of 6.5 m height and a width of 0.05m and an overflow drainage hole with the size of 1.5m length and 0.05 m width are considered in the above homogenous rectangular dam. the computed free seepage surface and the waterhead contours are shown in fig. 12. it can be seen that the free surface depresses rapidly through the leakage drainage hole and towards the downstream water level when it passes through the drainage gallery and the overflow drainage hole is filled with water. 3.2. large-scale application in engineering practice in this section, the ivfm, extended by considering densely spaced drainage holes as internal boundaries according to section 4, is applied for determining the monolithic seepage field in the vicinity of a hydropower station currently under construction in china. 3.2.1. hydrogeological features the water conservancy project is located in an l-shaped bay area where the river is deeply-incised in a v-shaped valley. the river is always in a turbulent state and the altitude, depth and width of the river are about 676~678 m, 7~11 m and 60~80 m respectively. the right bank is the concave bank of the river while the left bank is the convex bank. the thick river bed cover of the dam foundation consisted of a floating pebble layer, pebble layer, sand lens layer with a drifting pebble layer and an erratic boulder layer. in general, the thickness is about 40.0~60.0 m and can reach to 75.36 m in the deeplyincised channel area. i) the floating pebble layer is mainly distributed in a grade ii terrace of the left bank upstream of the dam axis with a thickness of 40~50 m. the front borehole of the figure 10. the locations of the seepage points from ivfm with a different number of gaussian points. figure 11. the locations of the free surface using the different methods. figure 12. the calculated waterhead distribution in the homogenous rectangular dam. g eologia c roatica yan jun et al.: a new numerical method for the analysis of monolithic seepage problems with complex drainage systems in a groundwater recharge area ... 53 figure 13. plan view of the distribution of the hydropower station. figure 14. typical section of the earth core rockfill dam in the hydropower station. figure 15. three dimensional fe mesh. g eo lo gi a c ro at ic a geologia croatica 72 / special issue54 terrace shows that the maximum thickness is about 70.72 m and the altitude of the top surface of the layer is about 730.0~734.0 m. the basal layer directly overlies the bedrock at an altitude of about 620.0~660.0 m. ii) this pebble layer is distributed in both a i grade terrace and the bottom of riverbed. the residual thickness at the base of the riverbed is about 22.0~32.0 m. the altitudes of table 1. permeability coefficients used in the calculation. material permeability coefficient (cm/s) rockfill 1.00×10-1 transition layer 3.00×10-2 filter layer 5.00×10-3 earth core 1.00×10-5 high-plastic clay 1.00×10-6 rock 1 (weakly weathered) 1.70×10-4 concrete cut-off wall 1.00×10-7 rock 2 3.00×10-5 overburden layer 8.15×10-2 grouting curtain 5.00×10-6 construction spoil 1.00×10-1 table 2. computation parameters of the direct method and the substructure method. methods degrees of freedom prescribed relative error computing time cpu utilization rate (%) number of iteration steps direct method 74592 10-5 3196.52 50 16 substructure method 4200.35 65 18 figure 16. plan view of the distribution of the free surface in the monolithic seepage field. figure 17. the distribution of the waterhead contours at the typical cross-section of dam. g eologia c roatica yan jun et al.: a new numerical method for the analysis of monolithic seepage problems with complex drainage systems in a groundwater recharge area ... 55 the upper and lower surfaces are about 635.0~640.0 m and 597.0~620.0 m, respectively. iii) the distribution of the drifting pebble layer is mainly on the surface of the current riverbed and the floodplains, overlapping the sand-lens layer with a drifting pebble layer with a thickness of 10.0~25.0 m. the project area is mainly composed of pre-sinian epimetamorphic basalt, tuff and rhyolite porphyry of the suxiong formation of the lower sinian, with the chengjiang granite and a quaternary loose accumulation layer. i) the bed rock of presinian hypometamorphic basalts is mainly exposed in the right bank valley slope and buried in the bottom of the river bed. ii) the lower sinian suxiong formation rocks exhibit well developed columnar joints with columnar diameters ranging from 0.3 m to 0.8 m and the distribution area is large, mainly exposed on both sides downstream of the junction area. iii) the chengjiang period granite intrusions are widely exposed in the left bank upstream and downstream of the junction area. the right bank represents only a small amount of the distribution in the niri estuary. the rock mass is hard, complete and of good quality which is the main engineering utilization rock mass within the scope of the project. 3.2.2. dam structure and power station as shown in fig. 13, the underground powerhouse is located on the left bank of the dam. at the upstream side of the underground powerhouse, three drainage galleries and four arrays of drainage holes, the latter with a diameter of 76.0mm each are equally spaced at 4.0m, are provided, as shown in fig. 5. figure 14. shows the cross section of the rock-filled dam with a maximum height of 186m. it is built on a deep overburden layer with a maximum thickness of 75m. the anti-seepage system of the dam and the foundation includes the earth core, two concrete cut-off walls and the grouting curtains. the normal water level of the reservoir and the tailwater level are 850.0m and 670.0m, respectively. 3.2.3. numerical simulation figure 15. shows the three-dimensional fe mesh for this hydropower station, consisting of 74592 nodes and 67748 linear 3d finite elements. it consists of the dam body, the underground powerhouse, (approximated by a cuboid), the surrounding rock mass and 147 leakage drainage holes and 49 overflow drainage holes. because of the large number of drainage holes, the method for considering densely spaced drainage holes in section 4 serves as an essential means for the efficient modeling of drainage holes at a similar accuracy by means of the substructure technique, however, at reduced computing time. because of the underground powerhouse, a larger domain of the rock mass is discretized on the left bank of the dam. the permeability coefficients of the different materials are summarized in table 1. setting er = 10 in the convergence criterion of eq. (14), requires 16 iteration steps to compute the free seepage surface. the computing time on a pc amd athlon (tm) 64 x2 dual core processor 4000+, 2.11ghz, memory 2.00g ram, is about 3200 seconds. compared with the direct method employed, considering drainage holes as internal boundaries, means that the substructure method is somewhat slower (table 2). figure 16. shows the plan view of the distribution of the free surface in the monolithic seepage field. it nearly matches the topography and is characterized by steep gradients in the vicinity of the dam body and the underground power house, reflecting the complex boundary conditions and the effects of the seepage-control and drainage measures. the waterhead isolines, displayed in figure 16. show a significant drop of the water head in the vicinity of the underground powerhouse. the water level of 650m at the upstream side of the powerhouse is almost equal to the bottom elevation of the lowest drainage gallery. thus, the drainage galleries and densely-spaced drainage holes at the upstream face of the powerhouse significantly reduce the water pressure acting on the powerhouse. the waterhead isolines for the vertical typical sections of dam and powerhouse are displayed in figs. 17 and 18, respectively. fig. 17 shows that: (i) the upstream water level in the rock mass is higher than the water level of the reservoir, (ii) the downstream water level in the rock mass is higher than the tailwater level, (iii) the free seepage surface drops from 850m to 675m inside the earth core, accounting for 97% of the water level differfigure 18. the distribution of the waterhead contours at the typical cross-section of the powerhouse. g eo lo gi a c ro at ic a geologia croatica 72 / special issue56 ence between the upstream and the downstream side of the dam, (iv) a large reduction of the waterhead is caused by the concrete walls and the grouting curtains, effectively cutting off the seepage passing through the overburden foundation, whereas smooth changes of the waterhead occur in the deep overburden. the waterhead isolines, displayed in fig. 18, show a significant drop of the free surface in the vicinity of the underground powerhouse. the water level of 650m at the upstream side of the powerhouse is almost equal to the bottom elevation of the lowest drainage gallery. thus, the drainage galleries and densely-spaced drainage holes at the upstream face of the powerhouse significantly reduce the water pressure acting on the powerhouse. 4. conclusions monolithic seepage problems with complex drainage systems are commonly faced in hydraulic engineering, slope engineering and underground engineering. typically, they are non-linear problems. in this study, a new fe method was presented for monolithic seepage problems, which is characterized by analyzing the overall unconfined seepage flow by the proposed improved virtual flux method (ivfm) simultaneously with the local seepage field in the vicinity of the complex drainage system. the latter usually consists of leakage drainage holes and overflow drainage holes, which are modeled as internal boundaries. compared to the previously proposed virtual flux method, in the ivfm the accuracy of the computed conductivity matrices in transition elements, i.e., the finite elements which contain the free surface, is improved by increasing the number of gauss points for the numerical integration and by introducing a regularized heaviside function for distinguishing between the domain below and above the free surface of a particular transition element in the integration procedure. these improvements allow the use of coarser fe-meshes and in addition, adaptive remeshing can be avoided. these features are especially important for the analysis of large-scale 3d seepage problems in engineering practice. the proposed method was verified by comparing numerical and analytical results for an academic seepage problem, for which the analytical solution is available. subsequently, the effectiveness and robustness of the proposed method was demonstrated by the large-scale 3d numerical simulation of the mono lithic seepage field in the vicinity of a hydropower station with a complex drainage system, currently under construction in china. acknowledgement this research was financially supported by the national key technologies research & development program (2017yfc0804600) and national natural science foundation of china (grant no. 51379220). references alt, h.w. (1980): numerical solution of steady state porous flow free boundary problems.– numerische mathematik, 36/1, 73–96. doi:10.1007/bf01395990. azusa, o., takahiro, h., dennis, b. & jun, s. (2018): evaluations of the downward velocity of soil water movement in the unsaturated zone in a groundwater recharge area using δ18o tracer: the kumamoto region, southern japan.– geologia croatica, 71/2, 65–81. doi: 10.4154/gc.2018.09. bathe, k.j, khoshgofta, a.r. & mohammad, r. (1979): finite element free surface seepage analysis without mesh iteration.– international journal for numerical & analytical methods in geomechanics, 3/1, 13–22. doi:10.1002/ nag.1610030103. borja, r.i. & kishnani, s.s. (1991): on the solution of elliptic free boundary problems via newton’s method.– computer methods in applied mechanics & engineering, 88/3, 341–361. doi:10.1016/0045-7825(91)90094-m. chen, s.h., xu, q. & hu, j. (2004): composite element method for seepage analysis of geo-technical structures with drainage hole array.– journal of hydrodynamics, 16/3, 260–266. doi:10.1016/j.jfluidstructs.2003.09.001. chen, s.h., xue, l.l. & xu, g.s. (2010): composite element method for the seepage analysis of rock masses containing fractures and drainage holes.– international journal of rock mechanics and mining sciences, 47/5, 762–770. doi:10.1016/j. ijrmms.2010.03.011. chen, y.f., zhou, c.b., & zheng, h. (2008): a numerical solution to seepage problems with complex drainage systems.– computers and geotechnics, 35/3, 383–393. doi: 10.1016/j.compgeo.2007.08.005. desai, c.s. & li, g.c. (1983): a residual flow procedure and application for free surface in porous media.– advances in water resources, 6/1, 27–35. doi: 10.1016/0309-1708(83) 90076-3. fipps, g., skaggs, r.w. & nieber, j.l. (1986): drains as a boundary condition in finite elements.– water resources, 22/11, 1613–1621. doi: 10.1029/ wr022i011p01613. gabriella, b., kiss, f.m. & ladislav, a.p. (2016): hydrothermal processes related to some triassic and jurassic submarine basaltic complexes in northeastern hungary, the dinarides and hellenides.– geologia croatica, 69/1, 39–64. doi:10.4154/gc.2016.04. jansen, r.b., kramer, r.w., iii, j.l. & poulos, s.j. (1988): earthfill dam design and analysis.– advanced dam engineering for design, construction, and rehabilitation, 32/1, 305–308. doi: 10.1007/978-1-4613-0857-7_9. jing, h.u., qu, w.l. & jiang, y.m. (2005): study on parameter of composite element method for modeling drain hole in seepage analysis.– water resources & hydropower engineering, 6/1, 56–57. mao, c.x., duan, x.b. & li, z.y. (1999): numerical computation in seepage flow and programs application.– hohai university press, nanjing, 3–40. neuman, s.p. (1973): saturated-unsaturated seepage by finite elements.– journal of the hydraulics division asce, 99/2, 2233–2250. shu, z.y., deng, j.x. & li, l.g. (2007): application of element conduct matrix regulative method by encrypting gauss point in seepage analysis with free surface.– journal of sichuan university, 6/1, 48–52. doi:10.3969/j. issn.1009-3087.2007.01.010. su, b.y., guo, h.x. & zhan, m.l. (1999): research on the calculation of unsteady seepage by cut-off negative pressure method.– chinese jounal of geotechnical engineering, 5/2, 711–714. doi:10.1016/j.jfluidstructs.2004.09.004. wang, x.n. & huang r.q. (1997): gauss point method for seepage analysis with free surface.– hydrogeology and engineering geology, 6/3, 1–4. doi:10.16030/j. cnki.issn.1000-3665. 1997.06.001. wang, y. (1998): the modified initial flow method for 3-d unconfined seepage computation.– journal of hydraulic engineering, 29/3, 68–73. doi: 10.3321/j. issn:0559-9350.1998.03.015 zhang, y.t., chen, p. & wang, l. (1988): using initial flow method to analyze the unconfined seepage surface.– journal of hydraulic engineering, 29/2, 18–26. zhang, q.f. & wu, z.r. (2005): the improved cut-off negative pressure method for unsteady seepage flow with free surface.– journal of geotechnical engineering, 27/1, 48–53. doi:10.3321/j.issn:1000-4548.2005.01.007. zheng, h., dai, h.c. & liu, d.f. (2005): improved bathe’s algorithm for seepage problems with free surfaces.– rock and soil mechanics, 26/4, 505–512. doi:10.3969/j.issn.1000-7598.2005.04.001. zheng, h., liu, d.f., lee, c.f. & tham, l.g. (2005): a new formulation of signorini’s type for seepage problems with free surfaces.– international journal for numerical methods in engineering, 64/1, 1–16. doi: 10.1002/nme.1345. zhou, c.b., xiong, w.l. & liang, y.g. (1996): a new method for the solution unconfined seepage field.– journal of hydrodynamics, 10/1, 528–534. zhu, y.m. (1997): the equivalent nodal flux method for the calculation of darcy flow.– journal of hohai university, 7/1, 105–108. zhu, y.m. & su, b.y. (1991): procedure of virtual flux for seepage free surface with fixed mesh.– journal of hohai university, 5/2, 113–117. zhu, y.m. & zhang, l.j. (1997): solution to seepage field problem with the technique of improved drainage substructure.– journal of geotechnical engineering, 19/1, 69–76. gc_2-2013_kb.indd 1. introduction much of the sedimentary fi ll of the neogene pannonian basin system was deposited in the late miocene – early pliocene lake pannon, a large, long-lived, brackish lake populated by a highly endemic “ponto-caspian-type” biota. in particular, cardiid bivalves refl ect the extraordinary diversity with more than 200 species in the lake (müller et al., 1999; geary et al., 2000). whereas high diversity in some other groups, such as the gastropods, was achieved by a combined effect of in situ evolution and inheritance from early – middle miocene lakes (harzhauser & mandic, 2008), lake pannon cardiids probably all originated from ancestors living in the restricted marine environment of the middle miocene sarmatian sea (e.g. vrsaljko, 1999). historically, the fi rst signifi cant endemic cockle assemblage from the lake was described by hörnes (1862) from the village of árpád (today part of pécs), southern hungary. later these cardiids played an outstanding role in the classifi cation of miocene and pliocene brackish cockles of the entire paratethyan region. although similar faunas are well-known from the southern regions of the pannonian basin, especially in croatia (e.g. brusina, 1884; basch, 1990), some of the árpád species are very rare elsewhere. for example, the type species of the genus lymnocardium, l. haueri, has not been known to occur in any other locality (reports on l. haueri from serbia (stevanovic, 1951) and croatia (basch, 1990) refer to a morphologically clearly distinct form, probably another species). ab stra ct a classic but very rare “árpád-type”mollusc assemblage, representing the endemic fauna of the late miocene–early pliocene lake pannon, was discovered in kozármisleny (near pécs, southern hungary). the fossils were collected from silt layers deposited in the shallow sublittoral zone of lake pannon, exposed in an 8–10 m high road cut. the assemblage contained some very rare species, including the type species of the genus lymnocardium, l. haueri (m. hörnes). palynological investigations from the same layers failed to yield age-diagnostic dinofl agellates, and pointed to a brackish – freshwater depositional environment and warm temperate climate. keywords: pannonian basin, lake pannon, molluscs, palynomorphs, granulometry  geologia croaticageologia croatica a new occurrence of a classic “árpád-type” mollusc fauna from the upper miocene of kozármisleny, southern hungary  lajos tamás katona1, jános kovács2, imre magyar3, mária sütő-szentai4 and tibor berta5 1 natural history museum of bakony mountains, h-8420 zirc, rákóczi tér 3-5. hungary; (fi nci99@freemail.hu) 2 department of geology, university of pécs, h-7624 pécs, ifjúság str. 6, hungary; environmental analytical & geoanalytical research group, szentágothai research centre, university of pécs, h-7624 pécs, ifjúság str. 20, hungary; (jones@gamma.ttk.pte.hu) 3 research group for paleontology, hungarian academy of sciences-hungarian natural history museumeötvös university, pob 137, h-1431 budapest, hungary; (immagyar@mol.hu) 4 h-7300 komló, május 1. u. 7, hungary; (szentai.maria@gmail.com) 5 h-8200 veszprém, sólyi u. 2, hungary doi: 10.4154/gc.2013.08 geologia croatica 66/2 111–118 5 figs. zagreb 2013 geologia croatica 66/2geologia croatica 112 the original descriptions by hörnes (1862) were based on donated specimens, and the exact locality where the shells had been collected remained unknown. recently szónoky et al., (1999) measured a fossiliferous outcrop located immediately south of árpád. some 2.5 km ne of their locality, in the area of the village of kozármisleny, a road cut was deepened in 2008 as part of the construction of the m6 highway system, exposing fossiliferous silt layers deposited in lake pannon. when visiting the outcrop, we were allowed only a restricted time for scanning the sequence and collecting samples. the mollusc fauna of the outcrop, however, proved to be very remarkable. the 10 bivalve (including 8 cardiid) and 4 gastropod species correspond to the classic árpád fauna, containing the same morphological types and including some of the rarities (l. haueri, l. hungaricum, l. arpadense, pteradacna pterophora). this paper gives a brief account of the outcrop and its mollusc fauna, complete with the results of palynological investigations. 2. the kozármisleny outcrop the excavation site (46°05’n and 18°27’e) is located in the pécs basin, between the villages of kozármisleny and árpád (nagyárpád, today part of pécs) in southern hungary (fig. 1), at an elevation of 160 m above sea level. the pécs basin is fi lled with lacustrine, fl uvio-lacustrine, and aeolian deposits of miocene to pleistocene age. in the southern margin of the basin, the layers dip approximately 1–3° to the southsoutheast (sebe et al., 2008). the north to south oriented road cut exposed the deposits of lake pannon in an 8–10 m thick sequence below a thin pleistocene loess cover. the section is composed primarily of yellowish-gray, mediumto coarse-grained silt, with 20–30 cm thick intercalations of fi ne-grained silt. layers of both the eastern (a) and western (b) walls were numbered from bottom to top. layers of wall a (fig. 2) were continuously sampled at 10–20 cm intervals for laser diffraction grain-size analysis (fritsch analysette 22), following the approach of konert & vandenberghe (1997) and kovács (2008). the gray-coloured, fi ne silt layers were laminated. between the lamina, magnesium-oxide fi lms occurred. the yellowishgray, mediumto coarse-grained silt layers showed cross to wavy lamination. the mediumand fi ne-grained silts were very poorly-sorted, strongly positively skewed, and extremely leptokurtic (fig. 2, a2, 3, 5, 7, 9). their grain-size frequency curves were unimodal (fig. 3.). the coarse silts were also very poorly-sorted, strongly positively skewed, and extremely leptokurtic, but the grain-size frequency distributions tended to exhibit a weakly-developed bimodality (fig. 2., a1, 4, 6, 8, 10 and fig. 3.). the grain size parameters and the bimodality of the central parts of the frequency distributions (fig. 3.) indicate a shallow sublittoral depositional environment with occasionally signifi cant effects of wave action, characteristic of both marine (goldbery, 1980; tamura, 2004; barusseau, 2011) and lacustrine (xiao et al., 2012) environments. most of the layers seemed to be barren of molluscan fossils or contained only shell fragments, but silt layers a1 to a3 and a very-fi ne, yellow sand layer at the bottom of wall b (b1) contained abundant and well-preserved shells. figure 1: geographic position of the kozármisleny profi le. katona et al.: a new occurrence of a classic "árpád-type" mollusc fauna from the upper miocene of kozármisleny, southern hungary geologia croatica 113 3. molluscs apart from the fossiliferous layers a1 to a3 and b1, mollusc shells were also collected from debris at the foot of the walls. the following forms were identifi ed: congeria rhomboidea rhomboidea hörnes, 1862 (fig. 4d). well-preserved specimens, 5–7 cm in length and 4–5 cm wide, occurred in layers a1 to a3. several dozen specimens were collected, some with articulated valves, some as single valves. dreissenomya unionides fuchs, 1870 (fig. 4h). a single specimen was discovered, 4 cm long and 2.5 cm wide. lymnocardium arpadense (hörnes, 1862) (fig. 4j). a mass occurrence of single and articulated valves, ca. 3 cm in length and 2 cm in width, occurred in layer b1. lymnocardium haueri (hörnes, 1862) (fig. 4i). 3 specimens (length 4–4.5 cm, width 4 cm) were collected from layer b1. lymnocardium hungaricum (hörnes, 1862) (fig. 4e). three almost intact specimens and several broken ones and fragments were observed, mostly in layer a3. the valves are 7–9 cm long and 6–7 cm wide. lymnocardium majeri (hörnes, 1862) (fig. 4k). a large number of excellently preserved specimens were collected from layers a2 and b1, with an average size of 3 cm length and 2.5 cm width. lymnocardium rogenhoferi (brusina, 1884) (fig. 4m). four specimens, all belonging to the árpád morphotype, were recovered from layer a2. none of the valves exceeded 2 cm in length. lymnocardium schmidti (hörnes, 1862) (fig. 4f). three specimens, 3–7 cm in length and 3–6 cm in width, were discovered in layer a3. caladacna steindachneri (brusina, 1884) (fig. 4n). two internal moulds (steinkern) were collected from layer a2. pteradacna pterophora (brusina, 1884) (fig. 4g). three partial specimens were collected from debris. radix kobelti (brusina, 1884) (fig. 4a). one specimen was observed in layer a1. radix lytostomopsis (brusina, 1902) (fig. 4b). one specimen occurred in layer a1. zagrabica cyclostomopsis brusina, 1884 (fig. 4c). 3 specimens were discovered, with an average size of 0.9 cm height and 0.6 cm width, in layer a1. figure 2: the kozármisleny road cut (wall a) with grain-size distribution curves of the upper miocene layers. figure 3: grain-size spectra of samples from diff erent layers in wall a. geologia croatica 66/2geologia croatica 114 figure 4: molluscs from the kozármisleny profi le. a: radix kobelti, b: radix lytostomopsis, c: zagrabica cyclostomopsis, d: congeria rhomboidea rhomboidea, e: lymnocardium hungaricum, f: lymnocardium schmidti, g: pteradacna pterophora, h: dreissenomya unionides, i: lymnocardium haueri, j: lymnocardium arpadense, k: lymnocardium majeri, l: valenciennius reussi, m: lymnocardium rogenhoferi, n: caladacna steindachneri. scale bar: 2 cm for a–c, 1 cm for d–n. katona et al.: a new occurrence of a classic "árpád-type" mollusc fauna from the upper miocene of kozármisleny, southern hungary geologia croatica 115 valenciennius reussi (neumayr, 1875) (fig. 4l). two specimens were collected from layer a1. 4. palynological investigations three samples from layer a1 were collected for palynological analysis. the objective was to better assess the biodiversity in this environment, and to provide data for biostratigraphic and environmental interpretation. palynological samples were prepared using standard processing techniques at the laboratory of the hungarian geological institute. the samples were treated with hcl (36%) and hf (40%) to remove the mineral fraction, and a heavy liquid (zncl2, density 2.2 g/cm3) was used to separate the organic matter from the undissolved inorganic components. the organic residue was not sieved, and additional oxidation was unnecessary. organic residue was mounted in glycerine jelly and three slides were investigated. two dinocyst taxa, three fresh water algae and 18 sporomorph taxa were identifi ed. 4.1. dinofl agellates the dinofl agellate assemblage consisted of two forms: cf. batiacasphaera sp. drugg 1970, 12 specimens (fig. 5, 4), and gonyaulacaceae sp. indet. lindemann 1928, only one specimen (fig. 5, 7). the batiacasphaera-like dinocyst of layer a1 is poorly preserved. it is similar to those forms that occur elsewhere in the galeacysta etrusca zone, (younger than 8 ma) in having an intercalary archeopyle and punctated ornamentation, but differs from them in its habit and glassy appearance. gonyaulacaceae sp. indet. is well-preserved. a reworked origin for this specimen can be excluded. it resembles some wellknown dinofl agellates from the galeacysta etrusca zone (gonyaulax spinifera – g. digitalis), but its tabulation is not identical with them. neither form is suitable for a more precise biostratigraphic evaluation. their presence indicates a probable brackish environment. 4.2. chlorophyta the samples contained botryococcus braunii kützing 1849, a green alga common in both brackish and freshwater ecosystems worldwide. mougeotia laetevirens (a. braun) wittrock 1877 and a freshwater spirogyra sp. indicate the presence or proximity of a freshwater environment. 4.3. sporomorphs the following forms were identifi ed: abiespollenites latisaccatus (trevisan 1967) krutzsch 1971 (fig.5, 6) abiespollenites maximus (krutzsch 1971) nagy, 1985 abiespollenites sivaki nagy, 1985 (fig.5, 8) abietinaepollenites microalatus (r. potonié, 1932) r. potonié, 1951 alnipollenites verus r. potonié, 1934 betulaepollenites betuloides (pflug, 1953) nagy, 1969 cedripites crassiundulicristatus (trevisan, 1967) krutzsch, 1971 (fig.5, 1–3) cedripites dacrydioides krutzsch, 1971 chenopodipollenites multiplex (weyland & pflug, 1957) krutzsch, 1960 ericipites callidus (r. potonié, 1931) krutzsch, 1970 hydrosporis levis krutzsch, 1962 nymphaeaepollenites pannonicus nagy, 1969 piceapollenites neogenicus (nagy, 1969) krutzsch, 1971 pinuspollenites labdacus (r. potonié, 1932) r. potonié, 1958 plantaginacearumpollenites miocaenicus nagy, 1963 polypodiisporites favus (r. potonié, 1931) r. potonié, 1933 tsugaepollenites verrucatus (krutzsch, 1971) nagy, 1985 (fig. 5, 5) ulmipollenites undulosus wolff, 1934 the coniferous species with abundant fi r (abiespollenites), pine (pinuspollenites), cedar (cedripites) and less spruce (piceapollenites) refl ect the composition of a distant mountainous vegetation. the broad-leaved forms are represented by birch (betulapollenites) and elm (ulmipollenites), the ferns are represented by polypodiisporites and laevigatosporites. alder (alnipollenites) probably occurred at the lake shore and in marshes. grasses barely appeared in the samples. the aquatic vegetation is represented by fl oating ferns (hydro sporis) and water lilies (nymphaeaepollenites). this pollen spectrum can be readily compared to those of other late miocene and early pliocene samples from the transdanubian region of hungary, such as those in drill cores from lake balaton (nagy-bodor, 1988) and from the borehole pula-3 (nagy, 2005), respectively. in spite of all the similarities, the kozármisleny samples contain less broadleaved species and fewer grasses than the two other spectra, and indicate a relatively humid, warm temperate climate. 5. discussion and conclusions as indicated by grain size and sedimentary structures, the silt layers of the kozármisleny outcrop were deposited in the shallow sublittoral zone of lake pannon. the ecological demand of molluscs supports this interpretation. l. majeri, l. rogenhoferi, pteradacna pterophora, and valenciennius are known to have been sublittoral dwellers. l. arpadense, similarly to its ancestor l. diprosopum, however, usually occurs in littoral sands (geary et al., 2010). at the time of deposition, the lake shore was situated a couple of kilometres to the northwest, possibly in the mecsek mountains. recently sebe et al., (2013) described the occurrence of a wave-cut geologia croatica 66/2geologia croatica 116 platform, together with the mollusc dreissenomya unioides, a burrowing dreissenid (also present in the kozármisleny fauna), from the southern slope of the mecsek mountains, at 380 m above sea level. the diverse cardiid assemblage seems to indicate brackish water, whereas the algae and sporomorphs argue for a brackish to freshwater environment. spores and pollen indicate a warm temperate climate. the palynological investigations failed to identify agediagnostic dinofl agellates. the great similarity of the mollusc fauna to the classic árpád one however, allows inference of the prosodacnomya vutskitsi zone (7–5 ma). although the árpád outcrop displays more sand layers, the close proximity and identical fauna suggests that the two outcrops, árpád and kozármisleny, expose the same sedimentary rock body. figure 5: pollen and algae from layer a1. 1–3: cedripites crassiundulicristatus (trevisan, 1967) krutzsch, 1971 (55–56 μm); 4: cf. batiacasphaera sp. (drugg, 1970) (56 μm); 5: tsugaepollenites verrucatus (krutzsch, 1971) nagy, 1985 (54 μm); 6: abiespollenites latisaccatus (trevisan, 1967) krutzsch, 1971 (133 μm); 7: gonyaula caceae sp. lindemann, 1928 (46×39 μm); 8: abiespollenites sivaki nagy, 1985 (94 μm). katona et al.: a new occurrence of a classic "árpád-type" mollusc fauna from the upper miocene of kozármisleny, southern hungary geologia croatica 117 acknowledgment the authors thank krisztina sebe, viktória baranyi, and two anonymous reviewers for their comments on the earlier version of the manuscript. the geological institute of hungary, and personally director lászló kordos, is thanked for having the palynological preparations processed. the authors thank the department of physical and applied geology, eötvös university, budapest and the natural history museum of bakony mountains, zirc, for their support. sedimentological analyses were carried out in the department of geology, university of pécs. this contribution was made possible through fi nancial support by the miksa hantken foundation, and developing competitiveness of universities in the south transdanubian region (srop-4.2.1.b-10/2/ konv -2010-0002). this is mta-mtm-elte paleo contribution no. 180. references barusseau, j.p. (2011): infl uence of mixtures of grain-size populations on the parametric and modal characteristics of coastal sands (hérault, mediterranean sea, france).– j. sediment. res., 81, 611–629. doi: 10.2110/jsr.2011.46 basch, o. (1990): cardiidae (mollusca, lamellibranchiata) pontskog kata u hrvatskoj.– palaeontol. jugoslavica, 39, 1–158. brusina, s. (1884): die fauna der congerienschichten von agram in kroatien.– beiträge zur geologie und paläontologie österreichungarns und orients, 3, 125–187. drugg, w.s. (1970): some new genera, species and combinations of phytoplankton from the lower tertiary of the gulf coast, u.s.a.– proc. north am. paleont. convention, part g, 809–843. fuchs, t. (1870): beiträge zur kenntnis fossiler binnenfaunen iii. die fauna der congerienschichten von radmanest im banate.– jahrbuch der k.k. geologischen reichsanstalt, 20, 343–364. geary, d.h., hunt, g., magyar, i. & schreiber, h. (2010): the paradox of gradualism: phyletic evolution in two lineages of lymnocardiid bivalves (lake pannon, central europe).– paleobiology, 36, 592–614. doi: 10.1666/08065.1 geary, d.h., magyar, i. & müller, p. (2000): ancient lake pannon and its endemic molluscan fauna (central europe; mio-pliocene).– in: rossiter, a. & kawanabe, h. (eds.): ancient lakes: biodiversity, ecology, and evolution. advances in ecological research, 3, 463–482. goldbery, r. (1980): use of grain-size frequency data to interpret the depositional environment of the pliocene pleshet formation, beer sheva, israel.– j. sediment. res., 50, 843–856. doi:10.1306/212 f7b08-2b24-11d7-8648000102c1865d harzhauser, m. & mandic, o. (2008) neogene lake systems of central and south-eastern europe: faunal diversity, gradients and interrelations.– palaeogeography, palaeoclimatology, palaeoecology, 260, 417–434. hörnes, m. (1862): die fossilen mollusken des tertiaer-beckens von wien.– conchifera (acephala), 2, 1–479. konert, m. & vandenberghe, j. (1997): comparison of laser grain-size analysis with pipette and sieve analysis, a solution for the underestimation of the clay fraction.– sedimentology, 44, 523–535. doi: 10.1046/j.1365-3091.1997.d01-38.x kovács, j. (2008): grain-size analysis of the neogene red clay formation in the pannonian basin.– int. j. earth sci., 97, 171–178. doi: 10.1007/s00531-006-0150-2 krutzsch, w. (1962): atlas der mittelund jungtertiären dispersen sporenund pollensowie der mikroplanktonformen des nördlichen mitteleuropas lieferung i.–veb deutscher verlag der wissenschaften, berlin, 108 p. krutzsch, w. (1970): atlas der mittelund jungtertiären dispersen sporenund pollensowie der mikroplanktonformen des nördlichen mitteleuropas lieferung vii.– veb gustav fischer verlag, jena, 175 p. krutzsch, w. (1971): atlas der mittelund jungtertiären dispersen sporenund pollensowie der mikroplanktonformen des nördlichen mitteleuropas lieferung vi.– veb gustav fischer verlag, jena, 234 p. kützing, f.t. (1849): species algarum.– f.a. brockhaus, lipsiae, 922 p. lindemann, e. (1928): abteilung peridineae (dinofl agellatae).– in: engler, a. & prantl, k. (eds.): die natürlichen pfl anzenfamilien nebst ihren gattungen und wichtigeren arten insbesondere den nutzpfl anzen. zweite stark vermehrte und verbesserte aufl age herausgegeben von a. engler, 2 band, 3–104. müller, p., geary, d.h. & magyar, i. (1999): the endemic molluscs of the late miocene lake pannon: their origin, evolution, and family-level taxonomy.– lethaia, 32, 47–60. doi: 10.1111/j.1502 3931.1999.tb00580.x nagy, e. (1963): some new spore and pollen species from the neogene of the mecsek mountains.– acta botanica, 34, 387–407. nagy, e. (1969): palynological elaborations the miocene layers of the mecsek mountains.– annales instituti geologici publici hungarici, 52, 237–649. nagy, e. (1985): sporomorphs of the neogene in hungary.– geol. hungarica ser. palaeontol., 47, 1–235. nagy, e. (2005): palynological evidence for neogene climatic change in hungary. – occasional papers of the geological institute of hungary, 205, 1–120. nagy-bodor, e. (1988): palynological study of pannonian and holocene deposits from lake balaton.– annual report of the hungarian geological institute of 1988, 535–568. neumayr, m. & paul, c.m. (1875): congerienund paludinenschichten slavoniens und deren faunen. ein beitrag zur descendenz-theorie.– abhandlungen der kaiserlich-königlichen geologischen reichsanstalt, 7, 1–111. pflug, h.d. (1953): zur entstehung und entwicklung des angiospermiden pollens in der erdgeschichte.– palaeontographica b, 95, 60–171. potonié, r. (1931): pollenformen der miozänen braunkohlen.– sitzber. geselsch. nat. freunde berlin, 13, 24–26. potonié, r. (1932): pollenformen aus tertiären braunkohlen.–jahrbuch preuss. geol. l. a., vol. 52, 1–7. potonié, r. (1933): über die morphologie der fossilen pollen.– sitzber. ges. naturf. fr., berlin, 516 p. potonié, r. (1958): synopsis der gattungen der sporae dispersae i– vi. sinopsis ii teil: sporites (nachträge), saccites, aletes, praecolpates, polyplicates, monocolpates.– beich. geol. jb., 31, 1–114. sebe, k., csillag, g. & konrád, g. (2008): the role of neotectonics in fl uvial landscape development in the western mecsek mountains and related foreland basins (se transdanubia, hungary).– geomorphology, 102, 55–67. doi: 10.1016/j.geomorph.2007.05.018 sebe, k., konrád, g. & magyar, i. (2013): on the position and age of the highest-lying lake pannon deposits in the mecsek mts. (sw hungary).– földt. közl., 143, 445–468. stevanović, p.m. (1951): pontische stufe im engeren sinne – obere congerienschichten serbiens und der angrenzenden gebiete. serbische akademie der wissenschaften, sonderausgabe 187, mathematisch-naturwissenschaftliche klasse no. 2, beograd. 361 p. szónoky, m., dobos-hortobágyi, e., gulyás, s., müller, p., szuromi-korecz, a., geary, d.h. & magyar, i. (1999): árpád, a classic locality of lake pannon bivalves.– acta geol. hung., 42, 89–108. geologia croatica 66/2geologia croatica 118 tamura, t. (2004): preservation and grain-size trends of holocene wave-dominated facies successions in eastern japan: implications for high-resolution sequence stratigraphic analysis.– j. sediment. res., 74, 718–729. doi: 10.1306/021304740718 trevisan, l. (1967): pollini fossili del miocene superiore nei tripoli del gabbro (toscana).– palaeontographica ital., 32, 1–78. vrsaljko, d. (1999): the pannonian palaeoecology and biostratigraphy of mollusks from kostanjek – medvednica mt., croatia.– geol. croat., 52, 9–27. weyland, h. & pflug, h.d. (1957): die pfl anzenreste der pliozänen braunkohle von ptolemais in nordgriechenland i.– palaeontographica b, 102, 96–109. wittrock, v.b. (1877): on the development and systematic arrangement of the pithophoraceae, a new order of algae.– nova acta regiae societatis scientiarum upsaliensis, ser. 3, 1–80. wolff, h. 1934: mikrofossilien des pliozänen humodils der grube freigericht bei dettingen a. m. und vergleich mit älteren schichten des tertiärs sowie posttertiären ablagerungen.– arb. inst. paläobot. und petr. d. brenn., 5, 55–86. xiao, j., chang, z., fan, j., zhou, l., zhai, d., wen, r. & qin, x. (2012): the link between grain-size components and depositional processes in a modern clastic lake.– sedimentology, 59, 1050–1062. doi: 10.1111/j.1365-3091.2011.01294. manuscript received april 16, 2013 revised manuscript accepted may 07, 2013 available online june 19, 2013 2017 | 70/2 | 105–114 | 13 figs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction application of mathematics in geology is relatively new approach in the interpretation of subsurface geology. geostatistics, as a part of geomathematics began its development in the second half of the last century. two great scientists are the founders of the kriging method: prof. dr. daniel krige and prof. dr. george matheron. the kriging method is a mathematically advanced interpolation method, which estimates the value of the variable in the grid. this method is very well described in krige (1951) and matheron (1965). common application, as well as the intensive development geostatistical methods paralleled the software development and the appropriate it infrastructure altogether. geostatistical methods can be divided into deterministic and stochastic methods. in deterministic methods, all the conditions which can influence the estimation have to be completely known. deterministic results can be unambiguously described by the completely known finite conditions, so deterministic ana­ lysis can only offer one solution. it is clear that the true geological model in the subsurface is singular, but since the description of the subsurface is based on well data (point data), it is not possible to be certain that the solution obtained with geostatistical methods is the correct one. this is why all geostatistical methods contain some uncertainty; they are a way of estimating the subsurface conditions and they can provide only the most probable solution, in other words the model which is the closest to the real conditions. in reservoir characterization, petrophysical modelling, especially the porosity modelling is important for getting insight into the spatial variability of different properties. in the case that porosity is mostly connected with the depositional environment of the reservoir rocks in the study area, this may pave the way for application of deterministic and stochastic geostatistical methods in petrophysical modelling – a case study of upper pannonian reservoir in sava depression kristina novak zelenika1, renata vidaček1, tomislav ilijaš1 and petar pavić1 1 inaoil industry plc. exploration and production of oil and gas, sector for geology and reservoir management, avenija većeslava holjevca 10, 10020 zagreb, e-mails: kristina.novakzelenika@ina.hr; renata.vidacek@ina.hr; petar.pavic@ina.hr doi: 10.4154/gc.2017.10 abstract deterministic methods are still widely used for reservoir characterization and modelling. the result of such methods is only one solution. it is clear that our knowledge about the subsurface is uncertain. since stochastic methods include uncertainty in their calculations and offer more than one solution sometimes they are the best method to use. this paper shows testing of the deterministic (ordinary kriging) and stochastic (sequential gaussian simulations) methods of reservoir properties distribution in the lower pontian hydrocarbon reservoirs of the sava depression. reservoirs are gasand oil-prone sandstones. ten realizations were obtained by sequential gaussian simulation, which are sufficient for defining locations with the highest uncertainties of distributed geological variables. the results obtained were acceptable and areas with the highest uncertainties were clearly observed on the maps. however, high differences of reservoir property values in neighbouring cells caused the numerical simulation duration to be too long. for this reason, ordinary kriging as a deterministic method was used for modelling the same reservoirs. smooth transitions between neighbouring cells eliminated the simulation duration problems and ordinary kriging maps showed channel sandstone with transitional lithofacies in some reservoirs. interpretation of sedimentary environments and depositional mechanisms. within the present study, new porosity modelling has been performed with the aim of introducing and analysing the uncertainty of reservoir properties. different deterministic and stochastic distribution methods were tested and analysed to choose the most acceptable one. 2. geological description of the study area within the sava depression generally, during the late pannonian and early pontian, many subsided structural units in the entire pannonian basin system were reactivated due to the thermal subsidence (malvić & velić, 2011). accommodation space for a huge volume of sedi­ ments was created. during these periods, the main regional sandstone hydrocarbon reservoirs were deposited in the sw part of pbs (velić, 2007). turbidites were the dominant clastic transport mechanism in the croatian part of the pannonian basin system during the late pannonian and early pontian (e.g. rögl, 1996, 1998; vrbanac, 1996). although there are some theories about the local material source, it was proven that most of material originates from the eastern alps. due to lengthy transport distances, only the medium and fine grained sands and silts reached the sava depression. in the calm period, when turbiditic currents were not active, typical calm hemi-pelagic marls were deposited. the study area is located in the north-western part of the sava depression. the location itself is a hydrocarbon field with a structure of an asymmetrical brachianticline, with a somewhat longer axis of northwest-southeast strike, and with a slightly pronounced peak in the southern part. a fault system of nw-se strike extends along the western part of the field. article history: manuscript received january 31, 2017 revised manuscript accepted june 14, 2017 available online june 28, 2017 keywords: geostatistics, ordinary kriging, sequential gaussian simulations, hydrocarbon reservoirs, sava depression g eo lo gi a c ro at ic a geologia croatica 70/2106 the lithological composition of the reservoirs is fairly simple – medium and fine­grained sandstones (lithoarenites) in continuous alternation with marls. marls are compact, dense brown-grey rocks. both sandstone and marl layers are not always continuous; there are frequent pinch-outs and sections where different sandstone layers are in direct contact. the whole series was divided into 11 sandstone intervals, referred to here as s1 to s11. s1 to s4 are saturated with gas (in the gas cap) and oil rim, and they represent one hydrodynamic unit. s5 to s10 are saturated with oil, representing a second hydrodynamic unit, while s11 is watersaturated. all of the reservoirs in the series (s1-s11) were classified as representing the upper pannonian. some of the reservoirs (s2, s3, s5, s7 and s10) are elongated in the nw­se direction and they have the geometry of channel sediments. according to porosity and net pay distribution in the model it could be assumed that those reservoirs have the coarsest material deposited in the channel centre, which laterally, toward channel borders changes into basinal marls through transitional lithofacies (sandy marls and marly sandstones). other reservoirs (s1, s4, s6, s8, s9 and s11) have greater areal extents and minor thickness variability representing rather sand lobes or similar type of deposits. 3. applied geostatistical methods some methods give only one solution, i.e. for the same input data and by applying the same method, the result is always going to be the same, i.e. the same map is constructed. these are the deterministic methods, although it is correct to call them deterministic interpolation methods. such methods are still commonly used for reservoir characterization and modelling, despite the fact that our knowledge about geological processes is far from complete. still, we are aware that such deterministic interpretation cannot be unambiguous and certain, but it is often described as the most probable. since a completely deterministic system is almost impossible by nature, it might be better to use stochastics wherever possible. stochastic methods are a standard part of mathematical geology and are increasingly being used as an integral part of the tools for hydrocarbon reservoir characterizations worldwide. alternatively, stochastic realizations provide a different number of solutions for the same input data set. those solutions can be very similar but never identical which is why all obtained solutions or results are equally probable. in stochastic processes the number of realizations can be any number we desire. the more realizations there are, the lower the uncertainty, i.e. there is a higher certainty that a number of realizations are close to the real geological situation. 100 realizations is the most common number in practice because it gives a level of certainty that is high enough for reservoir characterizations. there are conditional and unconditional simulations. in conditional simulations, the well data are considered as hard data, unlike in unconditional simulations where these data are not constant. the explanation for this approach is that well data is just point data extrapolated to the whole cell in the 3d reservoir model. cell dimensions in the model generally are 50 x 50 or 100 x 100 m and the point data again give some uncertainty. if the well had been positioned slightly differently, the cell in the 3d model would probably have different property values. this is why the point data in unconditional simulations is „surrounded” with measured data variance and the cell value will be chosen within this interval. generally, conditional simulations are more often used. 3.1. basics about ordinary kriging method the kriging method is one of the mathematically advanced deterministic interpolation methods. it is used for variable value estimation at the grid points. the result is a continuous surface created from a set of input points (figure 1). this method was named by a mining engineer and professor at the johannesburg university, d.g. krige, who developed this to estimate the gold concentration of a mine (krige, 1951). other scientists including de wijs, (1951), matheron, (1965), hohn, (1988), isaaks & srivastava, (1989), and dubruble, (1998) continued to develop the method. the goal of the method is to determine spatial relationships between real, measured data and the location where the value should be estimated. as a first step of kriging mapping, variogram analysis must be performed. therefore, except for the distance between a measured and estimated location, the local or kriging variance was taken into account. this means that the difference between the expected and estimated values is minimal. during kriging estimation each data item is weighted by the weighting coefficient (λ). kriging estimation is given by the simple equation (1): ∑ = ⋅= n i iik zz 1 l (1) where: zk – estimated value λi – weighting coefficient at the „i“ location zi – real, measured data at the „i“ location the most often used kriging technique is ordinary kriging, where the sum of all weighting coefficients must be 1. an expression for the ordinary kriging estimation technique is given by the matrix equation (2): figure 1. the process of ordinary kriging (http://www.bisolutions.us/a-brief-introduction-to-spatial-interpolation.php) g eologia c roatica novak zelenika et al.: application of deterministic and stochastic geostatistical methods in petrophysical modelling – a case study of upper ... 107 1 1 1 2 1 1 1 2 1 2 2 2 2 2 1 2 1 1 1 1 1 1 0 1 n n n n n n n n (z z ) ( z z ) ... ( z z ) ( x x) (z z ) ( z z ) ... ( z z ) ( x x) (z z ) ( z z ) ... ( z z ) ( x x) ... g g g l g g g g l g g g g l g m      − − − −      − − − −           ⋅ =       − − − −                  (2) where: γ – variogram value; z1....zn – real, measured value at the locations 1 to n; x – location where new value should be estimated; μ – lagrange multiplicator. 3.2. basics about sequential gaussian simulations sequential gaussian simulations are very well described in geiger (2006) and malvić (2008). basically, they are not an interpolation method, but after normal transformation, the data are most often defined by the properties of a normal distribution and estimation is performed in cells without well data to produce simulations. a random choice of location is used to estimate one cell (the first introduction of randomness, i.e., stochastic). the value of the selected cell is estimated mostly by kriging from other points in a spatial model. it is important to note that these points can be hard data or previously simulated points. after a cell is estimated deterministically, a new value is „surrounded” by the interval ±3s (using the variance of the „zero” solution). using a random choice (the second introduction of randomness), any value from this interval can be accepted as simulated for the cell. the procedure is repeated until estimates of all cells have been made (figure 2). it is important to emphasize that all realiza­ tions are equally probable. it is quite clear that the more realizations there are the lower the uncertainty is. 10 realizations, which are performed in the first phase of this study could just provide a rough insight into the area of the highest uncertainty in the analysed reservoirs, which later was actually the area with few or even without any well data. although all realizations are equally probable, it is impossible and meaningless to show them all. realizations p5, p25, p50, p75 and p95 or just p5, p50 and p95 are most often presented. realization p5 shows a solution where 5% of all solutions have lower values and realization p95 shows solution where 5% of all solutions have higher values. such interpretation is valid for all other p realizations. following this pattern, realization p50 should represent a mean value because 50% of all realizations have higher, and 50% have lower values than the selected one. the main advantage of sgs is the possibility for estimating values in all cells of a model through a set of realizations. there is however a disadvantage, e.g., simulated values can be significantly different in neighbouring cells, which can cause many problems in numerical simulation as proven by sensitivity performed on required simulation time. although this may not be a problem in cases with large cells which may better describe the subsurface than interpolation. 4. input data and modelling process input data set used for geological model construction comprised well log data (from 86 wells), quantitative log analysis, core data (from 28 wells) and previously constructed 3d structural models. all these data have been integrated and analysed. a new geolo gical model was built in petreltm, with cell dimensions of 50 x 50 m. the vertical resolution of the cells is 2.5 m. 4.1. structural modelling a reliable structural model is a precondition for performing petrophysical modelling. the tops and bottoms of the 11 sandstone reservoirs (22 horizons) together with interlayered marls determined 21 zones. two types of reservoirs were recognised: reservoirs with relatively uniform gross reservoir thickness in the field area and those with great lateral thickness variability. the latter have been identified as channel bodies. according to these observations, a layering method within the individual zones in the model was adopted. it was concluded that a better layering method in the case of channel bodies with great lateral variability of thickness was layering with constant layer thickness and following the top of reservoir, while in the other cases proportional layering was chosen. so, layering with constant layer thickness (2 m) was performed by „follow top” method for the s2, s3, s5, s7 and s10 „channel” reservoirs, and „proportional“ type of layering was performed for s1, s4, s6, s8, s9 and s11 sandstones. differences between „follow top“ and „proportional“ types of layering are shown in figure 3. figure 2. the process of sequential gaussian simulations. g eo lo gi a c ro at ic a geologia croatica 70/2108 4.2 petrophysical modelling (porosity distribution) analysis of petrophysical parameters was performed using: (1) the old deterministic petrophysical log analyses of effective porosity and; (2) porosity measured on core samples. cored wells and intervals, as well as wells with petrophysical log analysis are evenly distributed all over the field and are representative of the lithological and petrophysical parameters of the analysed lower pontian sandstone series. after correction of core porosity for overburden pressure, depth correlation of log analyses and coring data was performed. in most cases smaller corrections were necessary (up to 5 m) during correlation of depth intervals (figure 4). input data for porosity modelling included porosity measured on core samples as well as porosity resulting from deterministic petrophysical log analyses. a significant porosity mismatch has been observed (especially for porosity values from 0 to 15%) when comparing core porosity data (corrected for overburden pressure and adjusted by depth) and the data obtained by petrophysical log analyses. the relationship between well log and core data is given by equation 3 and figure 5: y = 0.545x + 12.71 (3) where: y = overburden corrected core porosity x = porosity from petrophysical log analysis generally, porosity obtained by the petrophysical log analysis was significantly underestimated (especially for the interval from 0 to 15%) compared to porosity measured on core samples under reservoir conditions. quality control of acquired well log data and performed analysis showed that the available data set consisted mainly of old, low resolution spontaneous potential, gamma ray and resistivity data but lacked in measured porosity figure 3. two types of layering method; „follow top” used for channel bodies, and „proportional”, used for reservoirs with relatively uniform gross reservoir thickness (novak zelenika et al., 2016). g eologia c roatica novak zelenika et al.: application of deterministic and stochastic geostatistical methods in petrophysical modelling – a case study of upper ... 109 logs. the measured spontaneous potential represented the main input for deterministic calculation of effective porosity. porosity measured on core samples obviously was not taken into account in the process of petrophysical log analysis. however, since the main scope of the case study presented here was the analysis of different methods of petrophysical modelling and their influence on reservoir simulation results, no new petrophysical analyses were performed. therefore, the mathematical relationship (eq.3) has been applied on porosity coming from petrophysical log analysis in order to obtain more reliable porosity data. the results are figure 4. depth shifting between the core and log effective porosities (novak zelenika et al., 2016). figure 5. cross plot diagram of porosity (core) vs. porosity (petrophysical analysis of well logs). linear correlation was established. g eo lo gi a c ro at ic a geologia croatica 70/2110 corrected porosity logs for all wells having porosity logs from quantitative log analysis. corrected porosity logs were then upscaled in the model representing the input for porosity modelling. upscaling is a process of averaging input data in the model cells containing well data. in this way just one value is assigned to a cell. there are different upscaling methods, i.e. logs can be upscaled as minimum, maximum or arithmetic mean, and other properties can be also used to bias the estimated value. in the upscaling process of the study, the scale-up method was the arithmetic average. original and upscaled corrected porosity were analysed using histogram plots for each reservoir separately as illustrated on figure 6. for reservoirs s6 and s5. quality control of corrected log porosity values showed that the whole range of data between 0 and 12% porosity is missing as a consequence of the unique mathematical relationship applied. moreover, there is an evident mismatch between the input data and upscaled data as a result of averaging in upscaling. for that reason, a new relationship between the log and core data using simple linear regression was established by two equations; one for the lower (eq. 4) and another one (eq. 3) for the higher porosity values (figure 7.): y = 1.6x (4) after applying the two different equations for the high and low porosity values, a quality check using histograms (figure 8) showed that porosity values in the range from 0 to 12% were refigure 6. original and upscaled porosity histograms, observe that the whole range of data between 0 and 12% porosity is missing in the input data as a consequence of the applied single linear mathematical relationship. figure 7. cross plot diagram porosity (core) vs. porosity (petrophysical analysis) with linear relationships established separately for low and high porosity value intervals (novak zelenika et al., 2016). g eologia c roatica novak zelenika et al.: application of deterministic and stochastic geostatistical methods in petrophysical modelling – a case study of upper ... 111 covered. also, the match between the input corrected log porosity and upscaled values was considered satisfactory. modelled, ordinary kriging distributed values showed lower values than the original data (figure 8) because the mean and the variance of the kriging estimates are considerably less than the true values. the mean values are lower because kriging performs declustering of the original data and the variance is lower because of the smoothing effect of kriging. the general trends are reproduced quite well (deutsch & journel, 1997). before porosity distribution, data analysis was performed and variograms for each reservoir were calculated (figure 9). different stochastic and deterministic methods of porosity distribution were examined. in the first phase, 10 realizations of sequential gaussian simulations (sgs) of porosity distribution were performed. figure 10 shows two different realizations for the s6 and s5 reservoirs. maps clearly show some areas with huge differences between estimated cell values in different realizations, for example the northern and north-western parts of the s6 reservoir and the eastern part of the s5 reservoir. these parts are areas with the highest uncertainty caused by a lack of well data. large differences between the neighbouring cell values can be also very clearly observed in all realizations (figure 10). due to the simulated values which were significantly diffe­ rent in neighbouring cells, problems occurred in fluid flow simulation during dynamic modelling as proved by the sensitivity performed on required simulation time (figure 11). implementation of sgs modelled porosity resulted in unacceptable simulation durations of 12–16 hours for approximately 20 years of production history. finally, to avoid problems in numerical modelling, porosity has been distributed using the ordinary kriging method (figure 12). a synthetic lithofacies log had been created based on poro­ sity (if the porosity was higher than 11% the lithofacies log represents sandstones, otherwise it represents marls), and it had been used as a bias for porosity upscaling. the value of 11% of porosity was chosen based on correlation between porosity and permeability. 11% porosity matches a permeability of 1*10­3µm2, which was proved as the lowest permeability for oil production in the studied reservoirs. in this way input porosity data are weighted according to prevailing lithofacies. porosity logs had been upscaled using arithmetic average methods for each reservoir. a channel sandstone body (s5 reservoir) is clearly observed in the central part of the ordinary kriging map (figure 12 right). it is clearly seen that the higher porosities are in the channel centre, while toward its borders porosity decreases. this could point to the existence of transitional lithofacies including sandy silts and silty sandstones. a smooth transition between neighbouring cells makes an ordinary kriging solution more acceptable in numerical modelling (figure 13). figure 8. histograms of porosity after applying the two equations. figure 9. variograms of porosity for the s6 and s5 reservoirs. g eo lo gi a c ro at ic a geologia croatica 70/2112 figure 11. illustration of simulation duration for different property model realizations (sgs realizations 1-5). figure 12. porosity distribution obtained by ordinary kriging in s6 (widely distributed over the area) and s5 (channels) reservoirs. g eologia c roatica novak zelenika et al.: application of deterministic and stochastic geostatistical methods in petrophysical modelling – a case study of upper ... 113 5. conclusion the analysed reservoirs, recently defined as lower pontian, consist of medium and fine­grained lithoarenites in continuous alternation with marls. marl layers are not always continuous and in some parts of the reservoirs sandstone layers are in direct contact with each other. the input data set used for geological model construction comprised well log data, quantitative log analysis (vintage data), core data and previous geological model. all these data have been integrated and analysed. a structural model was defined with 21 zones (11 sandstone reservoirs and 10 intercalated marl layers). two different layering methods were applied; „follow top“ for the reservoirs recognized as channel bodies with great lateral variability of thickness and „proportional“ for all others that did not show the geometry of channel sandstones but rather laterally extensive layers over the study area. corrections for overburden pressure and depth correlation of log analyses and coring data were performed. relationships between log and core data were established by two equations; one for the low and the other for the high porosity values. after variogram analysis for each reservoir was undertaken, different stochastic and deterministic methods of porosity distribution were examined. 10 realizations of sequential gaussian simulations were performed which enabled a clear insight into the reservoirs uncertainty. areas with the highest uncertainty were caused by a lack of data. realizations obtained by sequential gaussian simulations had significant differences between neighbouring cell values. consequences of such differences were many problems that occurred in numerical simulation, e.g. simulation time drastically increased. it can be concluded that well data alone are insufficient as an input for sequential gaussian simulations as a reservoir property distribution method. implementation of continuous data derived from 3d seismic volume as an additional input would certainly improve the results. porosity distribution obtained by ordinary kriging was more acceptable in numerical modelling, since the transition between neighbouring cells was very smooth and most probably better reflects the real geological picture. in the reservoirs recognized as channel bodies, higher porosities are located in the channel centre, while toward the channel margins porosities decrease. higher porosity values could represent pure sandstones. porosity decreasing towards the channel margins indicates sandstones with a more silty and marly component, i.e. to silty sandstones and sandy silts. dynamic simulation must match former production history as well as future production prediction. taking into account that the geological model represents the main input for numerical simulation of fluid flow, it is important that it fulfils the requirements of dynamic modelling process. one of these requirements is a reasonable simulation time. the study showed that selection of the reservoir property distribution methods have a significant influence on the applicability of the geological model in dynamic modelling. references deutsch, c.v. & journel, a.g. (1997): gslib: geostatistical software library and user’s guide.– 2nd edition, oxford university press, new york, 369 p. de wijs, h.j. (1951): statistics of ore distribution. part i: frequency distribution of assay values.– journal of the royal netherlands geological and mining society, 13, 365–375. dubruble, o. (1998): geostatistics in petroleum geology.– aapg education course note, series #38, aapg and geological society publishing house, tulsa, 210 p. geiger, j. (2006): the behavior of sequential gaussian simulation in the limits.– xth congress of hungarian geomathematics, may 18–20 2006, morahalom. hohn, m.e. (1988): geostatistics and petroleum geology.– van nostrand reinhold, new york, 264 p. isaaks, e. & srivastava, r. (1989): an introduction to applied geostatistics.– oxford university press inc., new york, 580 p. figure 13. simulation time (sgs realizations 1-5 and kriging) (novak zelenika et al., 2016). g eo lo gi a c ro at ic a geologia croatica 70/2114 krige, d.g. (1951): a statistical approach to some basic mine valuation problems on the witwatersrand.– journal of the chemical, metallurgical and mining society of south africa, 52, 119–139. malvić, t. (2008): primjena geostatistike u analizi geoloških podataka.– ina­industrija nafte, zagreb, 103 p. malvić, t. & velić, j. (2011): neogene tectonics in croatian part of the pannonian basin and reflectance in hydrocarbon accumulations.– in: new frontiers in tectonic research: at the midst of plate convergence (ed. schattner, u.), intech, rijeka, 215–238. matheron, g. (1965): les variables regionalisees et leur estimation:une application de la theorie des functions aleatoires aux sciences de la mature.– masson, paris, 306 p. novak zelenika, k., vidaček, r., ilijaš, t. & pavić, p. (2016): petrophysical modelling of the upper pannonian reservoirs in sava depression.– in: cvetković, m., novak zelenika, k., horváth, j. & hatvani, i.g (eds.): geomathematics – present and future of geological modelling, 8th hr­hu and 19th hu geomathematical congress, croatian geological society, zagreb, 105–112. rögl, f. (1996): stratigraphic correlation of the paratethys oligocene and miocene. mitteilungen ges. geol. bergbaustudenten österreich, 41, 65–73. rögl, f. (1998): palaeographic consideration for mediterranean and paratethys seaways (oligocene to miocene).– ann. naturhist. mus. wien, 99a, 279–310. velić, j. (2007): geologija ležišta nafte i plina.– faculty of mining, geology and petroleum engineering, university of zagreb, zagreb, 342 p. vrbanac, b. (1996): paleostrukturne i sedimentološke analize gornjopanonskih naslaga formacije ivanić grad u savskoj depresiji [palaeostructural and sedimentological analyses of late pannonian sediments of ivanić grad formation in the sava depression – in croatian].– unpub. phd thesis, faculty of natural sciences, university of zagreb, 121 p. 2019 | 72 / special issue | 71–80 | 5 figs. | 1 tab. | 2 app. tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society article history: manuscript received april 11, 2019 revised manuscript accepted july 08, 2019 available online december 20, 2019 keywords: rock slopes, hydropower engineering region, slope stability probability classification system, modification, hoek-brown strength criterion, csmr system 1. introduction slope rock mass is a type of very complex material with timespace variability. under the natural state, the rock mass not only has a long and complicated deformation history, but also includes many crisscrossed discontinuous planes such as joints and fractures after experiencing many orogenetic and tectonic movements. it has also usually been affected over a long period by many kinds of natural factors such as weathering and rainfall, as well as construction and other man-made factors. under complex geological conditions, it is difficult to accurately determine the spatial and temporal distribution of rock mass properties except through careful investigation and testing. therefore, it is difficult for any kind of mechanical model to describe its mechanical behaviour in an all-round and accurate way. pure theoretical calculation and experimental analysis often fail to solve practical problems. the problems often need geological engineers to make decisions on the base of their experience. because slope rock and soil mass is extremely complex, we are still far from a full and perfect understanding of its geological characteristics, deformation, strength and mechanical properties (chen, 2005). therefore, the study of rock slopes is still in the process of continuous exploration and improvement based on experience. the stability assessment of rock slopes in a hydropower engineering region is especially a very important and complicated issue. at present, rock mass classification systems provide a good approach and have been widely applied in the stability assessment of rock slopes by many researchers because they can consider many geological factors that affect slope stabi­ modification of slope stability probability classification and its application to rock slopes in hydropower engineering regions li xiu-zhena,b*, tan rong-zhia,b* and gao yanc a chinese academy of sciences, key laboratory of mountain hazards and earth surface process, 610041, chengdu, china; (lxzljt@imde.ac.cn) b chinese academy of sciences, institute of mountain hazards and environment, 610041, chengdu, china; (corresponding author: tanrz@imde.ac.cn / lxzljt@imde.ac.cn) c guizhou university, college of resources and environment engineering, 550025, guiyang, china doi: 10.4154/gc.2019.20 abstract stability assessment of rock slopes in hydropower engineering regions is an important and complex issue. rock mass classification systems are a good approach because they can thoroughly consider many factors influencing rock slope stability. the slope stability probability classification (sspc) system is a novel method. however, it has two limitations when applied to rock slopes: 1) it is only suitable for slopes less than 45 m in height, and 2) there is great subjectivity and randomness in the estimation of intact rock strength. therefore, this study presents two modifications of the sspc system by adopting the hoek-brown strength criterion and an empirical formula for maximum slope height. evaluation of results from of 34 typical rock slopes of the major hydropower engineering regions in china indicated that the accuracy rate of the modified sspc for stability evaluation of these slopes was 61.8%, and the accuracy for stability evaluation of 10 slopes with non-structural control failure was 80%. the stability values of stable and unstable slopes obtained using the modified sspc were different to those obtained using the chinese slope mass rating (csmr) and modified csmr systems. in addition, the identification accuracy rate of the modified sspc was significantly higher than that of the csmr and modified csmr. therefore, the modified sspc can be applied to hydropower engineering regions, providing a new means of rapidly evaluating the slope stability of high rock slopes (slopes > 45 m in height) in these regions. lity and obtain a quantitative empirical formula. since the 1870s, many scholars have put forward various rock mass classification systems for rock slope stability evaluation (pantelidis, 2009; russell et al., 2009; xiao, 2007; zheng et al., 2016), such as rock mass rating (rmr) by bieniawski (1974), slope mass rating (smr) by roman (1985), rock mass strength (rms) by selby (1980), slope rock mass rating (srmr) by robertson (1988), geological strength index (gsi) by hoek et al. (1988, 2002) and csmr for slopes in hydropower engineering region by chen et al. (1997). shi et al. (2005) proposed the highway slope mass rating (hsmr) system for rock slopes of mountain highways based on the smr. wu et al. (2005) proposed a general slope mass rating (gsmr) system applicable to the evaluation of rock slope stability based on a large number of practical engineering research projects. li et al. (2010) proposed a modified csmr using a continuous function to modify the systematically modify quantitative parameters in csmr. daftaribesheli et al (2011) applied fuzzy set theory to the rmr system and presented a fuzzy slope mass rating (fsmr) system. all of these classification systems provide an important means for the rapid evaluation of rock slope stabi lity (francioni et al., 2018; morales et al., 2019). however, most of the aforementioned systems for rock slope stability classification are based on a single weight value to evalu­ ate slope stability, and the failure mechanisms and modes of rock slopes are not strictly considered. for example, the slope stability of structural control failure is mainly affected by the structural plane condition and the relationship between the structural plane g eo lo gi a c ro at ic a geologia croatica 72 / special issue72 and slope orientation. however, the slope stability of non-structural control failure is mainly affected by the shear strength of the slope rock mass and height. in addition, the existing classification systems do not clearly distinguish an exposure rock mass and a slope rock mass, the characteristics of which may be quite different due to the influences of weathering and excavation (hack, 2002). hack put forward the slope stability probability classification (sspc) system in 1998 based on the aforementioned issues and the shortcomings of the existing slope stability classification systems (hack, 2002; hack et al., 2003). the sspc system resulted in great progress in the evaluation of the stability of rock slopes. for example, the adoption of a continuous formula during the calculation process ensures non­step classification results. the stability evaluation of rock slopes has been divided into orientation-dependent stability and orientation-independent stabi lity according to slope failure types. the evaluation result depends on the probability of slope failure in different modes, but not on a single weight value. the sspc system has been applied and developed in the study of highway slopes in spain for four years, and has also been applied in austria, south africa, new zealand, china, and the netherlands and has achieved good results (das et al., 2010; hack et al., 2003; li and xu, 2016; lindsay et al., 2000; lindsay et al., 2001; canal et al., 2016). the empirical formula of the sspc system is mainly based on the statistical analysis of 184 highway slopes with a slope height less than or equal to 45 m (hack et al., 2003), therefore, this system may be more suitable to the stability evaluation of rock slopes with a slope height less than 45 m. in addition, sspc emphasizes the influence of weathering and excavation on slope stability and pays relatively little attention to the intact rock strength compared to previous slope stability classification systems. in the sspc system, the parameter of intact rock strength is mainly estimated by field observation and a simple hammer test, which increases its subjectivity and randomness. lindsay et al. (2000) also noted that this estimating method of intact rock strength is the major shortcoming of the sspc system. the sspc system cannot be directly used to evaluate the stability of rock slopes in a hydropower engineering region as slope heights are generally greater than 45 m. a modified method of shear strength and maximum slope height of a rock slope in the sspc system was proposed in this study adopting the hoekbrown strength criterion and an empirical formula of maximum slope height, based on the limitations of slope stability evaluation in the sspc. an analysis of some case studies showed that the modified sspc can be used for probability evaluation of rock slope stability in a hydropower engineering region and can provide a new means for rapid evaluation of rock slope stability. 2. the sspc classification 2.1. overview the method considers three kinds of rock mass including exposure rock mass (erm), reference rock mass (rrm) and the slope rock mass (srm), obtains rock mass parameters based on investigation and testing on the slopes in the field, and identifies the possible failure mode and instability probability according to failure modes and mechanisms of the rock slopes. the erm is the rock mass in the exposure; the rrm is the rock mass in an imaginary, unweathered, and undisturbed condition prior to excavation; and the srm is the rock mass in which the existing or new slope is to be situated. compared to the smr classification systems, the sspc method has made great progress in the stability identification of rock slopes. the main advantages of the method include: (1) it has strong operability, and its evaluation parameters are easy to obtain in the field; (2) the continuous formulae are adopted in the calculation process, which guarantees the non-step property of the graded results; (3) evaluating orientation-independent slope stability is based on the classical slope stability analysis method, evaluating orientation-dependent slope stability embodies the controlling effect of structural surface condition and features values on the slope stability; (4) evaluation result depend on the probability valu es that the slope may occur in different failure modes, and does not only depend on a rating weight value such as the smr classification systems. 2.2. basic theory the concept of the sspc system is based on the following three aspects (hack, 2002). (1) a three­step classification system is introduced to describe the exposure rock mass, the reference rock mass, and the slope rock mass (fig. 1). (2) the slope stability is determined by the probable occurrence of different failure mechanisms instead of a single weight value. (3) unambiguous and simple procedures for data collection in the field. the assessment procedure of the method can be seen in figure 2. 2.3. evaluation indexes the evaluation indexes used in the sspc system mainly include intact rock strength, orientation, spacing and the number of discontinuity sets, shear strength characteristics of the discontinuities. the acquisition and quantification of intact rock strength in this classification system are mainly estimated by field observation and a simple hammer test. the relationship between the orientation of discontinuity and the orientation of slope determines the failure mechanism and failure mode of the rock slope. in the sspc system, the influence of the discontinuity orientation on the slope stability is mainly reflected in the change in the apparent dip (ap) of the structural surface. ap can be calculated using the following formula: arctan(cos( ) tan )s j jap α α β= − ⋅ (1) figure 1 sketch of exposures in rock masses of various degrees of weathering and different types of excavation indicating the concept of the ‘reference rock mass’ (hack, 2003). g eologia c roatica xiu-zhen et al.: modification of slope stability probability classification and its application to rock slopes in hydropower engineering regions 73 in this formula, αs is the slope direction, αj is the discontinuity dip direction, and βj is the discontinuity dip angle. in the sspc system, the combination of the spacing and the number of discontinuities is mainly quantified by three groups of discontinuities with the smallest spacing, according to the diagrammatic method proposed by taylor (1980). the conditions of the discontinuities determine their shear strength. the characteristics of the discontinuities are determined by four main factors: large-scale roughness (rl), small-scale roughness (rs), infill material (im), and karst (ka). a discontinuity condition factor (tc) can be determined by a multiplication of the four factors as follows: * *im*tc rl rs ka= (2) 2.4. evaluation rules the slope stability of the sspc system is determined using two analyses according to the failure mechanism and main control factors of the rock slopes: one is related to the orientation of the discontinuities and the slope (orientation-dependent stability), and the other is unrelated to the orientation of the discontinuities and the slope (orientation-independent stability). the former is for stability analysis of rock slopes of structural control failure, while the latter is for stability analysis of rock slopes of non-structural control failure. 1. orientation-dependent stability assessment this type of slope stability analysis mainly considers the condition of discontinuity planes, the relationship between dip direction and angle of discontinuity planes and dip direction and angle of slopes. according to the failure criteria of sliding and dumping, the failure probability of the rock slope in different modes is analysed, and the maximum probability is determined as the possible failure probability and the corresponding failure mode is taken as the possible failure mode of the rock slope. for sliding failure, the sspc system built a graph between the condition parameters of discontinuous plane and the apparent dip angle of discontinuous plane as a criterion to evaluate the stability probability of the slopes. for toppling failure, the relationship between the condition parameters of discontinuous plane and the apparent dip angle of discontinuous plane and slope angle is established as a criterion to evaluate the stability probability of slopes. 2. orientation-independent stability assessment this type of slope stability analysis adopts a linear shear plane model which follows the mohr-coulomb failure criterion. firstly, by determining the cohesion and internal friction angle of the slope rock mass, the maximum stability slope height is calculated. secondly, the ratio of the maximum stable slope height to the actual slope height and the ratio of the internal friction angle of the rock mass to the actual slope angle are calculated. finally, according to the linear shear plane failure model, the possible failure probability of rock slopes can be obtained by means of the related figures published in hack et al. (2003). detailed descriptions and related figures regarding the sspc method are available in hack (2002) and hack et al. (2003). 3. modification of the sspc for rock slopes in hydropower engineering regions 3.1. limitations of the sspc as previously mentioned, the empirical formula in the sspc system (such as the calculation formula of shear strength and the maximum slope height of a rock mass) is mainly based on the analysis of highway slopes in spain; thus, it is more suitable in the stability evaluation of slopes below 45 m in height. in addition, compared to previous slope stability probability classificafigure 2. flow diagram of the three-step concept of the sspc system (hack, 2003). g eo lo gi a c ro at ic a geologia croatica 72 / special issue74 tion systems, the sspc system emphasizes the influence of weathering and excavation on slope stability, while the intact rock strength is estimated via field observation and a simple hammer test. the estimation of the strength is strongly subjective in the sspc system (lindsay et al., 2001). in 2016, application of the sspc method in the stability assessment of highway slopes in china obtained good results (li & xu, 2016). the original plan was to use the sspc method to assess the stability of hydropower engineering slopes. however, it was discovered that the sspc system isn’t very suitable for the slopes in hydropower regions, due to the greater height of these slopes (generally more than 45 m). based on the limitations of slope stability evaluation in the sspc system, a modification method of shear strength and maximum slope height of rock slopes of non-structural control failure was proposed adopting the hoek-brown strength criterion and an empirical formula of maximum slope height, while the sspc system was still used to evaluate the stability of the rock slope of structural control failure. the specific modification methods are described below. 3.2. modification of srm strength in the sspc the modification of the shear strength of the srm of non­structural control failure is mainly based on the relatively perfect hoek-brown empirical strength criterion (hoek & brown, 1980, 1988; hoek, 1990; hoek et al., 2002). the calculation formula of parameters c′ and φ′ of the equivalent mohr­coulomb rock mass strength in a different range of slope height stress can be derived from the linear mohr-coulomb failure criterion and related rock mass parameters, including the geological strength index (gsi), lithological coefficient (mi), and the uniaxial compressive strength (σci) (hoek et al., 2002) as follows: ' ' 3 ' 1 3 ' 1 3 [(1 2 ) (1 ) ] (1 )(2 ) ( ) 1 (6 ( ) ) / ((1 )(2 )) ci b n a b n a b b n a s a m c a a s m am s m a a σ σ σ σ − − + + − = × + + + + + + + (3) ' 1 ' 1 3 ' 1 3 6 ( ) sin [ ] 2(1 )(2 ) 6 ( ) a b b n a b b n am s m a a am s m σ ϕ σ − − − + = + + + + (4) where ' 3 3max /n ciσ σ σ= , ciσ is the uniaxial compressive strength of the rock. ' 3maxσ is the upper limit of the stress range calculated using the bishop method under a different slope height, and it can be obtained using the following formulas: 0.91' ' 3max ' 0.72 cm cm h σ σ γσ −   =      (5) 1 ' ( 4 ( 8 ))( / 4 ) 2(1 )(2 ) a b b b cm ci m s a m s m s a a σ σ −+ − − + = ⋅ + + (6) where γ is the bulk density of the rock mass, mb is the material parameter of the rock mass, and a and s are parameters of the rock mass that can be obtained using the following formulas: 100exp 28 14b i gsim m d − = ⋅  −  (7) ( )/15 20/31 1 2 6 gsia e e− −= + − (8) 100exp 9 3 gsis d − =  −  (9) the three indexes of the rock mass; disturbance coefficient d, geological strength index gsi and lithological coefficient mi in formulae (7)–(9) can be determined based on the corresponding charts in marinos & hoek (2000) and chen et al. (2005) which provide further detail. 3.3 modification of slope height in sspc for a slope of non-structural control failure, huang (1994) calculated the critical slope of a homogeneous limited rock slope with different slope heights when the safety factor was 1, using the equilibrium limit analysis method. the empirical formula of maximum slope height was obtained based on the known lithology, the rock mass structure, rock strength, and rock weight using a regression and nonlinear method according to the analysis results (huang, 1994) as follows: i( 0.0003 m 0.0483)1.5 max (0.00651 0.00037 ) ( ) gsici ih m e σ γ − × += + × × × (10) where maxh is the critical height (m) representing the slope height when the tangent value of the slope angle is closer to infinity (the slope angle is near 90°), and the safety factor is equal to 1. the result of formula (10) better represents the real conditions of the slope (huang, 1994) and has been verified by engineering examples. therefore, this formula was used to calculate the maximum slope height of the slopes in this study. 4. preliminary application of the modified sspc to a rock slope in a hydropower engineering region 4.1. data source since the 1980s, numerous high and steep slope problems have occurred in china with the construction of many important hydropower projects. chen (2004) took part in many scientific research projects and advisory work regarding high and steep slope problems of the projects at a national and ministerial level. chen and his team (2004) established a database including 115 slopes in hydropower engineering regions during his implementation of the research projects. most of the slopes in the database have been subject to special investigation and research studies, and there are clear conclusions regarding their geometric characteristics, engitable 1. comparison of the accuracy of the stability identification systems applied to the 34 rock slopes. correct number and accuracy rate of evaluation csmr system modified csmr system modified sspc system 34 slopes correct number 14 15 21 accuracy 41.18% 44.12% 61.76% 10 slopes of non-structural control failure correct number 5 7 8 accuracy 50% 70% 80% g eologia c roatica xiu-zhen et al.: modification of slope stability probability classification and its application to rock slopes in hydropower engineering regions 75 neering geological characteristics, slope structure, discontinuity conditions, and stability conditions. in particular, for some of the rock slopes, there are complete and detailed stability classification indexes, such as uniaxial compressive strength, excavation methods, weathering strength, etc. therefore, 34 slopes in hydropower engineering regions with detailed evaluation indexes in the database were used to create case studies here (appendix tables, table a1). 4.2. process and steps the detailed analysis and calculation steps of the modified sspc system are as follows: (1) first, the lithology coefficient mi is determined according to the type of rock slope; the value of geological strength index gsi is comprehensively determined according to the rock type, weathering degree, rock mass structure and the conditions of discontinuities; the value of d is determined by interpolation in the range of 0 to 1 according to the slope excavation method; and the weight γ of different rocks is determined by referring to the rele­ vant manual of rock mechanics and the results of laboratory tests in chen’s database previously mentioned. (2) second, the value of the cohesive force c′ and internal friction angle φ′ of the rock mass of different slopes is calculated using the free roclab software (http://roclab.software.informer. com/), according to the hoek–brown strength criterion, and based on the known intact rock strength σc, geological strength index gsi, lithology coefficient mi, and disturbance coefficient d. then the ratio of internal friction angle and actual slope φ′/βs is calculated (appendix tables, table a2). (3) third, the maximum slope height hmax of different slopes can be obtained according to formula (10), and the ratio of the maximum slope height of the stable slope to the real slope height is calculated (appendix tables, table a2). (4) finally, the stability probability of the rock slope is obtained according to the value of φ′/βs and hmax/h, and referring to the original sspc system; then, the slope stability is evaluated according to the following criteria: when the slope stability probability sp ≤ 40%, the slope is unstable; when 40% < sp ≤ 70%, the slope is partially unstable; and when sp ≥ 70%, the slope is stable. 4.3. results characteristic information of 34 rock slopes was extracted from the slope engineering database of china’s key hydropower engineering region, which was created by chen (2004), such as lithology, slope structure, conditions of discontinuities, excavation method, and slope types (appendix tables, table a1). the stabili ty of the rock slopes was evaluated using the aforementioned modified sspc system, and the evaluation results are shown in table a2 of appendix tables. table a2 and fig. 3 show that the evaluation accuracy rate of the 34 slopes using the modified sspc system is 61.76% (21 are correct and 13 are incorrect). the slopes with the corresponding stability level have the largest proportion in each stability class (fig. 4). the evaluation accuracy rate of the 10 slopes of non­structural control failure reaches 80%. only the evaluations of the no. 2 and no. 17 slopes are incorrect, and the evaluation results of the other 8 slopes are consistent with the actual stability (table a2). 5. conclusion and discussion the sspc system was a slope stability probability classification system proposed by hack in 1998. via a three-step analysis method, it considered three types of rock mass, erm, rrm, and srm, and analysed the failure probability in different failure modes via field investigation, calculating various parameters of rock mass, and combined with the failure mode and failure mechanism of the rock slope, evaluated the potential failure mode and failure probability. the sspc system has resulted in great progress in the evaluation of rock slope stability compared to other classification systems. however, there are two limitations of this system: 1) it is more suitable for stability evaluation of slopes less than 45 m in height, and 2) there is a subjectivity in its compression strength estimation of intact rock. therefore, the sspc system may not be very suitable to the evaluation of rock slopes in hydropower engineering regions considering that most of the slope heights in such areas exceed 45 m. based on this, a modified method of shear strength and maxi­ mum slope height of a rock slope in the sspc system was proposed here adopting the hoek-brown strength criterion and an empirical formula of maximum slope height. the stability of 34 typical rock slopes in hydropower engineering regions in china was evaluated using the modified sspc system. the evaluation results indicated that the accuracy of the modified sspc system figure 3. distribution of 34 slopes on the probability map of orientation-independent stability using the modified sspc system. figure 4. percentage of slopes of different stability classes in each stability class g eo lo gi a c ro at ic a geologia croatica 72 / special issue76 for stability evaluation of these slopes was 61.76% and the accuracy for stability evaluation of 10 slopes of non-structural control failure was 80% (table 1). to further compare the application effectiveness of the modi­ fied sspc system, the stability of the aforementioned 34 rock slopes was completed grading the evaluation based on the csmr system put forward by chen et al. (1997) and the modified csmr system put forward by li et al. (2010). more details on these two methods are available in chen et al. (1997) and li et al. (2010). the evaluation results are shown in fig. 5 and table 1. table 1. shows that the value differences of slope stability eva­ luation obtained using the csmr and modified csmr systems are not significant, while the probability values of slope stability obtained using the modified sspc system are significantly different. slopes with different degrees of slope stability degree can be better separated (hack et al., 2002). moreover, the identification accuracy rate of the modified sspc system is obviously higher than that of the csmr and modified csmr systems (table 1). therefore, the modified sspc system can be applied to stability probability classification of rock slopes in a hydropower engineering region. it can provide a new effective means for the rapid stability evaluation of rock slopes in a hydropower engineering region with heights exceeding 45 m. however, it should be noted that the stability evaluation of structural control slopes in this study cannot further calculate and validate analysis since the field investigation data of the 34 slopes in the database are neither very detailed nor complete, particularly the occurrence, number and spacing of discontinuities. in practice, according to the sspc system, the analysis of orientation-dependent and orientation-independent stability should both be conducted and the lesser probability be taken as the final assessment result for a rock slope. acknowledgment this research was supported by the national key basic research program of china (no. 2015cb452704), natural science foundation of china (no.y8k1200200), and the open foundation of the state key laboratory of geohazard prevention and geoenvironment protection (sklgp2013k023). in particular, i would like to thank academician chen zuyu and professor wang yujie of the china water resources & hydropower science research institute for providing the slope database for the water conservancy and hydropower projects used in this study. references bieniawski, z.t. (1973): engineering classification of jointed rock masses.– the ci vil engineer in south africa, 15/12, 343–353. canal, a. & akin, m. (2016): assessment of rock slope stability by probabilistic-based slope stability probability classification method along highway cut slopes in adilcevaz-bitlis (turkey).– journal of mountain science, 13/11, 1893–1909. doi: 10.1007/s11629-016-3954-y chen, z.y., wang, x.g., yang. j., jia, z.x. & wang, y.j. (2005): rock slope stability analysis: principle, method, and procedure.– beijing: china water power press (in chinese). daftaribesheli, a., ataei, m. & sereshki, f. (2011): assessment of rock slope stability using the fuzzy slope mass rating (fsmr) system.– applied soft computing, 11/8, 4465–4473. doi: 10.1016/j.asoc.2011.08.032 das, i., sahoo, s., westen, c.v., stein, a. & hack, r. (2010): landslide susceptibility assessment using logistic regression and its comparison with a rock mass classification system, along a road section in the northern himalayas (india).– geo­ morphology, 114/4, 627–637. doi: 10.1016/j.geomorph.2009.09.023 francioni, m., stead, d., sciarra, n. & calamita, f. (2018): a new approach for defining slope mass rating in heterogeneous sedimentary rocks using a combined remote sensing gis approach.– bulletin of engineering geology and the environment, 1–22. doi: 10.1007/s10064-018-1396-1 hack, r. (2002): an evaluation of slope stability classification.– in: proceedings of the eurock, portugal, 3–22. hack, r. & price, d. (1993): a rock mass classification system for the design and safety analysis of slopes.– eurock, 803–810. hack, r., price, d. & rengers, n. (2003): a new approach to rock slope stability – a probability classification (sspc).– bulletin of engineering geology and the environment, 62, 167–184. hoek, e. (1990): estimating mohr-coulomb friction and cohesion values from the hoek– brown failure criterion.– international journal of rock mechanics & mining sciences & geomechanics, 27/3, 227–229. hoek, e. & brown, e.t. (1980): empirical strength criterion for rock masses.– journal of geotechnical and geoenvironmental engineering, 106/15715, 1013–1035. hoek, e. & brown, e.t. (1988): the hoek–brown failure criterion – a 1988 update.– journal of heuristics, 16/2, 167–188. hoek, e., carranza-torres, c. & corkum, b. (2002): hoek–brown failure criterion-2002 edition.– in: proceedings of the fifth north american rock mechanics symposium, toronto, 1–6. (c) modified sspc system figure 5. comparison of the different stability identification systems (a–c) applied to the 34 rock slopes. (b) modified csmr system (a) csmr system g eologia c roatica xiu-zhen et al.: modification of slope stability probability classification and its application to rock slopes in hydropower engineering regions 77 huang, g.x. (1994) a proposed susceptibility­index and influence zone of rock avalanche.– dissertation, national central university (in chinese). li, x.z., kong, j.m. & wang, c. (2010): modification of rock slope stability classification systems by continuous functions and its application.– chinese journal of rock mechanics and engineering, 29/supp.1, 3439–3446 (in chinese). li, x.z. & xu, q. (2016): application of the sspc method in the stability assessment of highway rock slopes in the yunnan province of china.– bulletin of engineering geology and the environment, 75/2, 551–562. lindsay, p., anderson, j., bourke, f., campbell, r.n. & clarke, l. (2000): predicting slope stability in open pit gold and coal mines.– in: new zealand minerals and mining conference proceedings, new zealand, 29–31. lindsay, p., campbell, r.n., fergusson, d.a., gillard, g.r. & moore, t.a. (2001): slope stability probability classification, waikato coal measures, new zealand.– international journal of coal geology, 45/2, 127–145. doi: 10.1016/s0166-5162(00)00028-8 lysandros, p. (2009): rock slope stability assessment through rock mass classification systems.– international journal of rock mechanics and mining sciences, 46, 315–325. marinos, p. & hoek, e. (2000): a geologically friendly tool for rock mass strength estimation. in: proceeding on geotechnical and geological engineering (geoeng2000, melbourne, australian). morales, m., panthi, k.k. & botsialas, k. (2019): slope stability assessment of an open pit mine using three-dimensional rock mass modelling.– bulletin of engineering geology and the environment, 78/2, 1249–1264. robertson, a.m. (1988): estimating weak rock strength.– in: proceedings of the sme annual meeting, phoenix, arizona, 1–5. roclab software (http://roclab.software.informer.com/) roman, m. (1985): new adjustment ratings for application of bieniawski classification to slopes.– in: proceedings of the international symposium on role of rock mechanics, zacatecas, mexico, 49–53. russell, c.p., santi, p.m. & humphrey, j.d. (2009): modification and statistical analysis of the colorado rockfall hazard rating system.– engineering geology, 104/1, 55–65. selby, m.j. (1980): a rock mass strength classification for geomorphic purposes: with tests from antarctica and new zealand.– zeitschrift für geomorphologie, 24, 31–51. shi, y.c., wang, z.w., wan, g.r., wang, z.y., chen, q.y. & tang, s.c. (2005): study of mountain highway slope mass rating.– chinese journal of rock mechanics engineering, 24/6, 939–944. taylor, h.w. (1980): a geomechanics classification applied to mining problems in the shabanie and king mines, zimbabwe.– dissertation, university of rhodesia. wu, d.b. & xu, w.y. (2005): gsmr method for determining rock slope mechanical parameters.– rock and soil mechanics, 26/9, 1421–1426. xiao, g.f. (2007): study on classification method of rock slope stability in highway construction in mountainous region.– dissertation, institute of rock and soil mechanical, the chinese academy of sciences (in chinese). zheng, j., zhao, y., lü, q., deng, j., pan, x. & li, y. (2016): a discussion on the adjustment parameters of the slope mass rating (smr) system for rock slopes. – engineering geology, 206, 42–49. doi: 10.1016/j.enggeo.2016.03.007 g eo lo gi a c ro at ic a geologia croatica 72 / special issue78 ta bl e a1 . b as ic c ha ra ct er is tic s a nd d at a of th e 34 sl op es in h yd ro po w er e ng in ee rin g re gi on . n um be r sl op e na m e li th ol og y ro ck m as s st ru ct ur e di sc on tin ui ty co nd iti on ex ca va tio n m et ho d sl op e ty pe σ c (m pa ) g si m i d γ （ m n /m 3 ） 1 ta ng y an gu an g la nd sl id e at th e zh ex i h yd ro po w er s ta tio n st ro ng ly w ea th er ed fi ne sa nd st on e in fil l s an dy sl at e bl oc ky po or na tu ra l s lo pe no nst ru ct ur al co nt ro l 35 45 7 0. 00 0. 02 8 2 1# la nd sl id e at th e li jia xi a d am st ro ng ly w ea th er ed c ho ris m ite a nd sc hi st lo os e po or na tu ra l s lo pe no nst ru ct ur al co nt ro l 45 20 29 0. 00 0. 02 7 3 2# la nd sl id e at th e li jia xi a d am st ro ng ly w ea th er ed c ho ris m ite a nd sc hi st lo os e po or na tu ra l s lo pe no nst ru ct ur al co nt ro l 48 20 29 0. 00 0. 02 7 4 th e w es t s lo pe a t t he t ia ns he ng qi ao h yd ro po w er st at io n bu ild in g w ea kl y w ea th er ed sa nd -s ha le m os ai c po or pr es pl itt in g sl op e st ru ct ur al c on tr ol 16 .1 35 6. 5 0. 25 0. 02 7 5 th e w at er -in ta ke sl op e of th e d on g fe ng h yd ro po w er s ta tio n w ea kl y w ea th er ed li m es to ne in fil l w ea k in te rc al at ed la ye r m os ai c po or pr es pl itt in g sl op e st ru ct ur al c on tr ol 60 45 9 0. 25 0. 02 5 6 th e cr ee p de fo rm at io n bo dy a t t he m id dl e da m si te of th e m ia o jia ba h yd ro po w er s ta tio n w ea kl y w ea th er ed m et a tu ff an d tu ffa ce ou s s la te ca ta cl as tic po or na tu ra l s lo pe no nst ru ct ur al co nt ro l 11 8 45 7 0. 00 0. 02 6 7 th e sl op e at th e sh i m ol in g re se rv oi r a re a w ea kl y w ea th er ed sa nd st on e, sh al e m os ai c sa tis fa ct or y na tu ra l s lo pe st ru ct ur al c on tr ol 11 5 30 6. 5 0. 00 0. 02 7 8 th e w at er -in ta ke sl op e of th e d a ch ao sh an h yd ro po w er s ta tio n st ro ng ly w ea th er in g ba sa lt in fil l r hy ol ite a nd py ro cl as tic ro ck ca ta cl as tic po or na tu ra l s lo pe st ru ct ur al c on tr ol 71 25 25 0. 00 0. 02 8 9 th e ab ut m en t s lo pe o n th e le ft b an k of th e la x iw a h yd ro po w er s ta tio n st ro ng ly w ea kl y w ea th er in g gr an ite ca ta cl as tic po or na tu ra l s lo pe st ru ct ur al c on tr ol 80 25 32 0. 00 0. 02 5 10 th e sl op e at th e n an y i h yd ro po w er s ta tio n bu ild in g w ea kl y w ea th er in g po rp hy rit ic g ra ni te bl oc ky sa tis fa ct or y pr es pl itt in g sl op e st ru ct ur al c on tr ol 10 5 35 25 0. 25 0. 02 5 11 th e sl op e at th e w o h us ha n h yd ro po w er s ta tio n sp ill w ay th ic k lim es to ne in fil l m ud st on e m os ai c po or pr es pl itt in g sl op e st ru ct ur al c on tr ol 43 45 9 0. 25 0. 02 6 12 th e sl op e at th e re se rv oi r a re a of s an b an xi h yd ro po w er s ta tio n st ro ng ly w ea th er ed tu ffa ce ou s s ilt st on e m os ai c po or na tu ra l s lo pe no nst ru ct ur al co nt ro l 50 45 7 0. 00 0. 02 5 13 th e sl op e at th e in le t o f t he d iv er si on tu nn el a t ta i p in gy i h yd ro po w er s ta tio n w ea kl y w ea th er ed g ra ni te bl oc ky po or co nv en tio na l bl as tin g st ru ct ur al c on tr ol 11 0 40 25 0. 50 0. 02 5 14 th e sl op e at th e in le t o f t he d iv er si on tu nn el a t th e li ji ax ia h yd ro po w er s ta tio n st ro ng ly w ea th er ed m ig m at ite in fil l s ch is t ca ta cl as tic po or sm oo th b la st in g st ru ct ur al c on tr ol 63 35 21 0. 50 0. 02 7 15 th e sl op e at ta i p in gy i h yd ro po w er s ta tio n ta ilr ac e st ro ng ly w ea th er ed g ra ni te m os ai c po or co nv en tio na l bl as tin g st ru ct ur al c on tr ol 11 0 35 25 0. 75 0. 02 5 16 th e sl op e at ta i p in gy i h yd ro po w er s ta tio n in ta ke w ea kl y w ea th er ed g ra ni te m os ai c sa tis fa ct or y co nv en tio na l bl as tin g st ru ct ur al c on tr ol 11 0 40 25 0. 75 0. 02 5 17 th e sl op e at th e ex it of 3 # c av e of m an w an h yd ro po w er s ta tio n co m pl et el y st ro ng ly w ea th er ed rh yo lit e ca ta cl as tic sa tis fa ct or y co nv en tio na l bl as tin g no nst ru ct ur al co nt ro l 90 30 25 0. 75 0. 02 6 18 th e sl op e at th e er ta n h yd ro po w er s ta tio n 2# ta ilr ac e w ea kl y w ea th er ed b as al t bl oc ky po or co nv en tio na l bl as tin g st ru ct ur al c on tr ol 12 0 45 16 0. 75 0. 02 8 g eologia c roatica xiu-zhen et al.: modification of slope stability probability classification and its application to rock slopes in hydropower engineering regions 79 n um be r sl op e na m e li th ol og y ro ck m as s st ru ct ur e di sc on tin ui ty co nd iti on ex ca va tio n m et ho d sl op e ty pe σ c (m pa ) g si m i d γ （ m n /m 3 ） 19 th e sl op e at th e er ta n h yd ro po w er s ta tio n sp ill w ay in le t w ea kl y w ea th er ed b as al t bl oc ky sa tis fa ct or y co nv en tio na l bl as tin g st ru ct ur al c on tr ol 15 0 45 16 0. 75 0. 02 8 20 h e jia la nd sl id e at th e m ia o jia ba h yd ro po w er s ta tio n w ea kl y w ea th er ed m et a tu ff ca ta cl as tic po or na tu ra l s lo pe st ru ct ur al c on tr ol 11 8 30 8 0. 00 0. 02 4 21 d a h ua ng ya sl op e at th e w u jia ng du h yd ro po w er s ta tio n st ro ng ly w ea th er ed th ic k lim es to ne in fil l m ud st on e bl oc ky po or na tu ra l s lo pe st ru ct ur al c on tr ol 75 40 9 0. 00 0. 02 5 22 g u sh iq un la nd sl id e at th e g on g bo xi a h yd ro po w er s ta tio n w ea kl y w ea th er ed g ne is s lo os e po or na tu ra l s lo pe no nst ru ct ur al co nt ro l 72 .9 25 28 0. 00 0. 02 7 23 th e sl op e on th e m ou nt ai n be hi nd th e ti an sh en gq ia o i h yd ro po w er s ta tio n bu ild in g sl ig ht ly -n ew ly m ed iu m th ic k m ud st on e in fil l s an ds to ne m os ai c sa tis fa ct or y un co nt ro lle d bl as tin g st ru ct ur al c on tr ol 36 50 11 0. 50 0. 02 5 24 th e sl op e at th e ti an sh en gq ia o i h yd ro po w er s ta tio n sp ill w ay sl ig ht ly w ea th er ed th ic k lim es to ne bl oc ky sa tis fa ct or y un co nt ro lle d bl as tin g st ru ct ur al c on tr ol 67 .5 55 10 0. 50 0. 02 5 25 sh i p in gt ai la nd sl id e at th e xi ao x ia sh i h yd ro po w er s ta tio n w ea kl y w ea th er ed m ig m at ite a nd m et as an ds to ne lo os e po or na tu ra l s lo pe st ru ct ur al c on tr ol 50 25 25 0. 00 0. 02 5 26 6# la nd sl id e at th e ji sh ix ia h yd ro po w er s ta tio n st ro ng ly w ea th er ed sa nd st on e an d co ng lo m er at e ca ta cl as tic po or na tu ra l s lo pe no nst ru ct ur al co nt ro l 68 .4 35 17 0. 00 0. 02 6 27 th e sl op e at th e m an w an h yd ro po w er s ta tio n st on e pi t w ea kl ysl ig ht ly w ea th er ed rh yo lit e bl oc ky go od pr es pl itt in g sl op e st ru ct ur al c on tr ol 85 50 25 0. 25 0. 02 6 28 1# la nd sl id e at th e ji sh ix ia h yd ro po w er s ta tio n st ro ng ly w ea th er ed sa nd st on e an d co ng lo m er at e lo os e po or na tu ra l s lo pe no nst ru ct ur al co nt ro l 67 20 17 0. 00 0. 02 6 29 th e sl op e at th e ti an sh en gq ia o ii h yd ro po w er s ta tio n su rg e ta nk st ro ng ly w ea th er ed sa nd -s ha le a nd c ru sh ed st on e m os ai c go od pr es pl itt in g sl op e st ru ct ur al c on tr ol 32 .2 45 11 0. 25 0. 02 7 30 th e st ee p cl iff sl op e on th e w es t s lo pe o f t he t ia ns he ng qi ao ii h yd ro po w er s ta tio n st ro ng ly w ea th er ed sa nd st on e an d sh al e bl oc ky go od co nv en tio na l bl as tin g st ru ct ur al c on tr ol 32 .2 45 11 0. 75 0. 02 7 31 th e w ed ge sl op e on th e rig ht b an k of th e m ia o jia ba h yd ro po w er s ta tio n w ea kl y w ea th er ed m et as an ds to ne a nd tu ff bl oc ky po or na tu ra l s lo pe st ru ct ur al c on tr ol 11 8. 5 45 13 0. 00 0. 02 5 32 h ua ng l as hi la nd sl id e at th e th re e g or ge s w ea kl ysl ig ht ly w ea th er ed li m es to ne a nd c la ys to ne m os ai c po or na tu ra l s lo pe no nst ru ct ur al co nt ro l 23 .6 9 45 8 0. 00 0. 02 6 33 th e sl op e in fr on t o f t he p u bu go u h yd ro po w er s ta tio n da m w ea kl y w ea th er ed b as al t bl oc ky sa tis fa ct or y na tu ra l s lo pe st ru ct ur al c on tr ol 90 50 25 0. 00 0. 02 8 34 th e sl op e at th e ti an sh en gq ia o ii h yd ro po w er s ta tio n so ut h fa ct or y bu ild in g st ro ng ly w ea th er ed sa nd -s ha le bl oc ky po or pr es pl itt in g sl op e st ru ct ur al c on tr ol 11 .5 45 12 0. 25 0. 02 8 ta bl e a1 . c on tin ue d. g eo lo gi a c ro at ic a geologia croatica 72 / special issue80 ta bl e a2 . t he a na ly si s r es ul ts o f t he m od ifi ed s sp c sy st em fo r t he 3 4 ro ck sl op es . n um be r sl op e he ig ht h (m ) sl op e an gl e β s (° ) c′ (m pａ ) φ ′( °) h m ax (m ) h m ax /h φ ′/ β s st ab ili ty p ro ba bi lit y sp ac tu al st ab ili ty 1＊ 20 0 35 0. 71 17 .2 0 13 3. 57 0. 67 0. 49 5% un st ab le 2＊ 25 5 32 1. 86 30 .5 2 23 6. 58 0. 93 0. 95 35 % un st ab le 3＊ 21 0 32 1. 86 30 .5 2 25 2. 35 1. 20 0. 95 57 % un st ab le 4 12 4 42 0. 42 18 .7 1 38 .1 8 0. 31 0. 45 3% pa rt ia lly u ns ta bl e 5 15 6 49 2. 40 25 .9 1 30 8. 22 1. 98 0. 53 85 % pa rt ia lly u ns ta bl e 6＊ 35 0 39 4. 80 26 .0 0 48 4. 95 1. 39 0. 67 92 % un st ab le 7 22 0 50 4. 61 25 .5 0 21 6. 28 0. 98 0. 51 39 % un st ab le 8 85 40 3. 12 30 .8 0 37 1. 01 4. 36 0. 77 97 % pa rt ia lly u ns ta bl e 9 25 0 50 3. 98 33 .6 2 61 8. 79 2. 48 0. 67 97 % un st ab le 10 15 0 73 6. 84 37 .9 7 92 4. 12 6. 16 0. 52 98 % st ab le 11 13 2 42 1. 72 25 .9 0 21 2. 40 1. 61 0. 62 96 % pa rt ia lly u ns ta bl e 12 ＊ 38 0 40 2. 05 26 .1 1 21 3. 71 0. 56 0. 65 4% un st ab le 13 12 0 70 6. 99 37 .4 7 11 87 .2 1 9. 89 0. 54 99 % pa rt ia lly u ns ta bl e 14 13 5 43 2. 39 25 .8 5 42 7. 41 3. 17 0. 60 97 % pa rt ia lly u ns ta bl e 15 11 0 35 4. 93 28 .9 6 96 8. 12 8. 80 0. 83 97 % pa rt ia lly u ns ta bl e 16 82 70 4. 93 28 .9 6 11 87 .2 1 14 .4 8 0. 41 10 0% st ab le 17 ＊ 17 0 45 2. 52 20 .1 7 62 1. 08 3. 65 0. 45 98 % un st ab le 18 11 0 52 4. 22 23 .4 2 91 6. 26 8. 33 0. 45 99 % pa rt ia lly u ns ta bl e 19 90 64 .5 4. 22 23 .4 2 11 45 .3 2 12 .7 3 0. 36 10 0% pa rt ia lly u ns ta bl e 20 88 0 43 3. 83 22 .8 4 28 9. 97 0. 33 0. 53 3% un st ab le 21 30 0 60 3. 06 26 .7 0 30 6. 73 1. 02 0. 45 45 % pa rt ia lly u ns ta bl e 22 ＊ 44 5 23 3. 33 31 .8 0 44 9. 00 1. 01 1. 38 70 % st ab le 23 14 0 45 1. 49 26 .4 4 27 3. 37 1. 95 0. 59 98 % st ab le 24 13 0 63 2. 99 27 .5 7 59 3. 92 4. 57 0. 44 96 % st ab le 25 11 9 35 2. 20 30 .8 0 29 2. 63 2. 46 0. 88 94 % st ab le 26 ＊ 33 0 45 2. 62 27 .4 4 38 7. 15 1. 17 0. 61 85 % st ab le 27 19 3 73 5. 97 39 .7 0 13 26 .5 1 6. 87 0. 54 98 % st ab le 28 21 8 31 2. 56 27 .4 4 19 8. 37 0. 91 0. 89 40 % un st ab le 29 12 0 43 1. 38 27 .5 3 18 0. 78 1. 51 0. 64 94 % st ab le 30 11 0 63 .4 0. 98 20 .6 7 18 0. 78 1. 64 0. 33 96 % pa rt ia lly u ns ta bl e 31 25 0 42 5. 92 31 .2 6 83 3. 75 3. 34 0. 74 97 % st ab le 32 ＊ 80 0 30 1. 01 27 .2 0 10 6. 98 0. 13 0. 91 2% un st ab le 33 30 0 37 5. 91 38 .4 5 13 04 .2 2 4. 35 1. 04 80 % st ab le 34 70 51 0. 51 28 .2 5 67 .2 0 0. 96 0. 55 35 % pa rt ia lly u ns ta bl e n ot e: “* ” i s t he sl op e of n on -s tr uc tu ra l c on tr ol fa ilu re . ab stra ct the grohovo landslide is the largest active slope movement along the croatian coast, situated on the north-eastern slope in the central part of the rječina river valley (north­eastern coastal part of adriatic sea, croatia). slopes in this valley are formed of siliciclastic rocks (i.e., fl ysch), while the limestone rock mass is visible on the cliffs around the top of the river valley. the slopes are at the limit of a stable equilibrium state, and slope movement phenomena have been recorded since the 19th century. samples for laboratory testing were taken from the fl ysch bedrock, weathered zone and slope deposits to provide specimens for determination of their mineralogical, physical and geotechnical properties. correlation between mine­ ralogical and geotechnical properties and their infl uence on sliding processes are presented here. the clay fraction in samples ranges from 17 % to 38 %. clay activity of the tested samples is from 0.45 to 0.89, and the residual friction angle varies from 13.0° to 17.7°. these results correspond to the presence of kaolinite and illite groups of clay min­ eral. both the mineral composition and decrease in strength of fi ne­grained soil materials, due to the increase of pore water pressures, contributes to slope movements. keywords: grohovo landslide, fl ysch, clay, geotechnical properties, mineral composition, grain size geologia croatica 67/2 127–136 9 figs. 1 tab. zagreb 2014 geotechnical properties in relation to grain-size and mineral composition: the grohovo landslide case study (croatia)  čedomir benac1, maja oštrić2 and sanja dugonjić jovančević1 1 university of rijeka, faculty of civil engineering, radmile matejčić 3, rijeka, croatia 2 croatian waters, department of rijeka, đure šporera 3, rijeka, croatia doi: 10.4154/gc.2014.09 the infi ltration of vadose water and increase of inter­particle and inter­aggregate pore water causes swelling of the mont­ mo rillonite and illite groups of clay minerals. these proces­ ses cause the fl ysch rock massto gradually increase in volume and soften while the clay content as well as the clay fraction increases. the mineral composition is a key factor control­ ling the value of residual friction angle fr for soils (skemp­ ton, 1985).the shear strength of soil greatly depends on the type of clay minerals present and the quantity of inter­ particle and inter­aggregate pore water (selby, 2005). the palaeogene fl ysch of the adriatic part of croatia is characterized by the alternation of fi ne­grained sedimentary rocks including shale, marl, silt and sandstone (marinčić, 1981).the ratio of each of these fi ne grained rocks within 1. introduction due to their geological complexity, fl ysch formations are dif fi cult to characterize from a geotechnical behaviour point of view. some attempts at applying rock mass classifi cation systems to these complex rock masses have been carried out (hoek & marinos, 2001). weathering processes signifi cantly infl uence changes of strength properties of the fl ysch rock mass. in the fi rst stage of weathering, characteristic grey­bluishcolour changes to yellow­brownish. the cause of this change is the oxidation of dispersed pyrite that expands in volume and destructs the original structure of the bedrock. the content of the clay frac­ tion in the weathered zone is increased by the alteration of silicate minerals in clay (attewell & farmer, 1979). geologia croaticageologia croatica geologia croatica 67/2geologia croatica 128 this rocky complex, varies greatly even in nearby locations. the flysch rock complex in the adriatic part has in the past been exposed to stresses of different intensity and direction (korbar, 2009). the investigated area is situated on the north-eastern slo pe of the rječina valley. this valley is a part of a dominant morphostructural unit which strikes in the direction of the klana – rječina river valley – sušačka draga valley – bakar bay – vinodol valley (fig. 1). the geological structure could be considered to be a palaeogene flysch syncline limited by faults, analogous with the tectonic style of the vinodol valley (blašković, 1999; benac et al., 2009). the unstable phenomenon studied here known as the grohovo landslide, is the biggest known active landslide on the adriatic coast and is located in the wider unstable zone with numerous features of dormant historical landslides. the slopes are at the limit of a stable equilibrium state, and several slope movement phenomena have been recorded since the end of the 19th century (vivoda et al., 2012). the dynamics and complexity of the whole phenomenon was presented in several papers (benac et al., 1999; benac et al., 2002; benac et al., 2005; benac et al., 2006). remediation works on landslide locations were never performed due to the huge displacement mass and relatively stable equilibrium state of the lower parts of the grohovo landslide body. measurements of benchmark movements and changes of groundwater level were provided periodically, every two to three months from 1998 until 2010. maximum displacements were determined in the upper part of the slope (benac et al., 2011). an advanced comprehensive monitoring system was installed on the grohovo landslide in 2011. it includes geodetic monitoring with an automatic total station measuring 25 geo­ detic benchmarks, a gps master unit and nine gps re ce i vers, as well as geotechnical monitoring equipment including vertical inclinometers, long-span extensometers, pore pressure gauges, seismographs and rain gauges (arbanas et al., 2012). yet, earlier papers do not contain analyses of the relationships between the mineral composition and geotechnical properties of silty clay from colluvial and weathering zone materials. due to the low strength parameters, a major part of the sliding surface was formed in these materials (be­ nac et al., 2005). the aim of this paper is to analyse the relationship between the geotechnical properties of the finegrained materials taken from the grohovo landslide location, with the grain size distribution and mineral composition. laboratory investigations performed in 2000 and considered in this research (igh, 2000), were supplemented with new specific mineralogical and geotechnical analyses to obtain more reliable results. consequently there are no uniform analyses performed on all 22 samples, which has aggravated interpretation of the results. 2. geological setting of the study area the unstable phenomenon on the north­eastern slope of the rječina valley is situated between the valići reservoir and the pašac bridge. the bottom of the valley is 150 to 200 m above sea level, and the peaks in the north­eastern side reach figure 1: a simplified geological map of the investigated area according to benac et al. (2009): 1 – upper cretaceous and palaeogene carbonate rocks, 2 – palaeogene siliciclastic rocks-flysch. figure 2: geological map of the grohovo landslide area: 1-palaeogene limestones, 2-palaeogene flysch rock mass mostly covered by colluvium, 3-alluvial sediments, 4-position of boreholes. benac et al.: geotechnical properties in relation to grain-size and mineral composition: the grohovo landslide case study (croatia) geologia croatica 129 a height of 412 m.the cretaceous and palaeogene limesto­ nes are situated on the top of the slopes, while the palaeogene siliciclastic rocks or flysch are located on the lower slo pes, including the bottom of the valley (fig. 2). during neo-tectonic and recent tectonic movements the limestone rock mass was repeatedly faulted and fractured. such tectonic movements and weathering processes enabled the separation of limestone blocks and their gravitational slid­ ing over the flysch bedrock, disintegration of the rock mass, as well as accumulation of talus deposits at the foot of the rock cliffs (benac et al., 2006). siliciclastic or flysch bedrock is characterized by great lithological heterogeneity, because of the frequent vertical and lateral alternation of different lithological sequences. microscopic petrological analysis of the bedrock has shown the presence of silty marl, laminated silt to silty shale, as well as fine­grained sandstones. unlike the limestones, the flysch rock mass is more prone to weathering, which results in a clayey weathering zone on the flysch bedrock. over time, coarse grained fragments of limestone, originating from the rock falls were mixed with clay from the weathered flysch zone forming several metre thick slope deposits (benac et al., 2005) (fig. 3). the grohovo landslide has the form of a complex landslide with 13 landslide bodies. according to the wp/wli suggested nomenclature for landslides (iaeg, 1990), the length of the displaced mass is ld = 420 m, width is wd = 200 m, and depth is dd = 6–20 m. the estimated total volume of the displaced mass is 850.000 m3. the total displacement of the landslide to eis more than 20 m in the initial state of slope movement (benac et al., 1999). the affected slope has distinctive filtration anisotropy. groundwater flow in cohesionless talus material is very ra­ pid, in contrast to cohesive talus material, where infiltration and water flow are very slow. subsurface groundwater can be accumulated locally in clayey to silty slope material and in the weathered bedrock zone. this water originates either from direct infiltration of precipitation, or from the karst aquifer on the top and behind the slope. the groundwater level changed less than 10 cm in the upper boreholes (g­5 and g­7), but varied up to several metres in the lower boreholes (g­1, g­2 and g­3) (fig. 2) (benac et al., 2005). 3. methods material samples have been recovered to provide specimens for laboratory testing to obtain data on their mineralogical, physical and geotechnical properties.the 22 representative samples were selected and taken from the flysch bedrock, weathering zone and from slope deposits­ colluvium. from a total of 22 samples, 18 were taken from borehole cores (fig. 3). the boreholes were drilled during the second phase of field investigation in 1999 (igh, 2000). the other 4 samples were taken from the surface during 2006 (fig. 2, 3 and 4, table 1). table 1 summarizes the results of all the performed tests. on 12 samples selected from borehole cores, quantitative and semi­quantitative mineralogical analyses were performed (no. 1­4, no. 6­9 and no. 13­16). for the purpose of mineralogical analysis, grain size distribution of the fine­ grained fraction (up to 1 mm) was also determined. this ana­ ly sis will be referred to as sedimentological methods of grain size analysis in the following text. in this way, the finer fraction percentage is additionally increased. one additional mineralogical analysis was performed on sample from the surface (no. 22). figure 3: photo of the core from borehole g-2: boring interval 0.0-4.0 m (photo: č. benac, 1999). borehole location is shown in fig. 2. geologia croatica 67/2geologia croatica 130 standard geotechnical laboratory tests were performed on 13 borehole samples (no. 2­5, 7, 10­12, 14­22) and on 4 surface samples (no. 19­22 in table 1). grain size analysis (sieving and hydrometry) were performed on all samples, according to astm standard (igh, 2000). on some of those samples, atterberg limits, plasticity index and water content were determined. results of sedimentological and geotechnical methods grain size distribution analysis are shown in fig. 5. the clay fraction (cf) refers to the percentage of particles <0.002 mm, as determined by geotechnical grain size analysis. most of the authors recognized that the use of cf as an indicator of platy shaped particles did not give real insight into the soil composition. measurement of the clay content (cc) proportion in total clay minerals indicates soil cha rac teristics more comprehensively than cf (tiwari & marui, 2005). however, for practical reasons, the use of cf for the description of soil behaviour is still more widely used (lupini et al., 1981; skempton, 1985). the cf in fig. 5b ranges from 17 % (no. 15) to 38 % (no. 14) (table 1). the sample (no. 20) has been analysed using a scanning electron microscope (philips xl­30). the minerals were iden­ tified by the habitus of crystallographic shapes and identification picks in the energy spectrum of x­rays (edax). shear strength tests were also performed on samples from borehole cores: three direct shear tests (no. 10­12) and one ring shear test (no. 3). additional ring shear tests were performed on surface samples (no. 19­22). direct shear tests were performed for normal stress of 50, 100 and 200 kpa to determine peak shear strength and ring shear tests for normal stress of 100, 200 and 300 kpa to determine residual shear strength (table 1). a remoulded specimen was used in ring shear tests in which the first shear surface was formed after consolidation and before shearing. 4. results both methods of grain size analysis, (sedimentological (fig. 5a) and geotechnical (fig. 5b)) show that the silt and clay fractions prevail in all samples. consequently, material can table 1: summarized results of analyzed samples. sample no. borehole /depth (m) grain size analysis cf w0 (%) wl (%) wp (%) ip (%) a= ip/cf im ring shear direct shear c (kpa) f (°)sediment. geotech. 1 g-1/ 5.0 m +               1.09         2 g-2/ 1.0 m + + 19           1.30         3 g-2/ 2.5 m + + 27 19.41 42.6 20.53 22.07 0.82 1.23 +   16.67 16.1 4 g-2/ 4.5 m + + 37           1.37         5 g-3/ 2.0 m   + 23                   6 g-3/ 3.0 m +               1.31         7 g-3/ 3.4 m + + 33           1.38         8 g-3/ 7.0 m +               1.02         9 g-3/ 10.3 m +               0.23         10 g-4/ 2.5 m   + 20 14.19 32.22 18 14.22 0.71   + 9.5 23.7 11 g-4/ 4.3 m   + 36 19.2 33.97 17.73 16.24 0.45   + 1.0 26.1 12 g-4/ 5.5 m   + 35 16.32 33.01 17.28 15.73 0.45   + 7.5 25.1 13 g-4/ 14.0 m +               0.68         14 g-5/ 1.0 m + + 31           1.54         15 g-5/ 4.5 m + + 17           0.68         16 g-5/ 8.5 m + + 26           1.14         17 g-6/ 11.0 m   + 32                   18 g-7/ 20.0 m   + 18                   19 g-1/ 0 m   + 28   41.14 23.75 17.4 0.62 +   0 13.0 20 g-2/ 0 m   + 27   37.41 21.72 15.69 0.58 +   0 14.5 21 g-3/ 0 m   + 27   37.38 22.5 14.88 0.55 +   0 17.7 22 g-4/ 0 m + + 19       16.99 0.89 2.14 +   0 15.0 benac et al.: geotechnical properties in relation to grain-size and mineral composition: the grohovo landslide case study (croatia) geologia croatica 131 be considered clayey silt or silty clay. fig. 5b shows that the average particle size (d50) according to geotechnical me­ thods of analysis ranges from 0.004 to 0.042 mm. fig. 5a shows a much wider range of d50 according to sedimentological methods analysis from 0.0028 to 0.056 mm. results of atterberg limit testing and plasticity indices are given in table 1 and are presented in fig. 6. besides showing consistency limits (liquid limit and index of plasticity) in fig. 6, areas of the main clay minerals: kaolinite and illite groups are also shown. the tested materials have low to medium plasticity according to the plasticity index (ip = 14–22 %), and liquid limit (wl = 32–43 %) respectively. clay activity is defined as the ratio of plasticity index (ip) and clay fraction (cf). this simple index gives the infigure 4: schematic borehole cross-sections with locations of the analyzed samples. figure 5: results of grain-size analysis: a-sedimentological method, b-geotechnical method. geologia croatica 67/2geologia croatica 132 sight into the mineral composition of materials (fig. 6 and 7). water quantity that can be absorbed within soil particles depends on the quantity and type of clay minerals. the highest clay activity occurs in the montmorillonite group, then illite and the lowest in the kaolinite group. active clays provide the most potential for expansion. activity of the tested samples ranges from a = 0.45 (no. 12) to a = 0.89 (no. 22). accordingly, samples for non­active clays (a < 0.75), include samples no. 10­12 and no. 19­21, and normally active clays (a = 0.75–1.25), for samples no. 3 and no. 22 (table 1). x­ray diffraction analysis was performed and the following minerals were identified: quartz, calcite, plagioclase, k­feldspar and phyllosilicates (fig. 8). quantitative mineralogical analysis detected the presence of the following clay figure 6: diagram of atterberg limits and plasticity indexes (according to grim, 1968). numbers refer to analyzed samples (table 1). figure 7: estimation of expansiveness of clay in analyzed samples (according: bell, 1993): numbers refer to analyzed samples (table 1). benac et al.: geotechnical properties in relation to grain-size and mineral composition: the grohovo landslide case study (croatia) geologia croatica 133 minerals: kaolinite, illite, chlorite, mixed­layer clay minerals, and in some samples vermiculite (not detected in sample no. 9) and smectite (not detected in sample no. 5­9 and no. 14­16) (igh, 2000). phyllosilicates in tested samples are prevalent and are re presented by micaceous minerals, kaolinite, vermiculite, smec tite and chlorite groups, and mixed­layer clay minerals. from the mineral composition of the fractions <4 μm, it is clear that the main clay minerals are illite and kaolinite and spo radic ones are vermiculite, smectite and mixed­layer clay mi nerals. sample no. 22 consists of illite­smectite minerals (fig. 8). quartz, calcite and phyllosilicates constitute 86–96 % of the mineral composition (fig. 8). quartz, calcite, and feldspar are the commonly observed massive minerals, while the most common types of clay minerals include: kao linite, illite, smectite, halloysite, chlorite and micaceous minerals. grains of partially dolomitized calcite are observed in sample no. 20 using the scanning electron microscope. clay minerals from chlorite or chlorite-illite groups have dimensions between 5–15 mm. the particles of albite (plagioclase group) have dimensions around 40 mm. micaceous minerals are visible only sporadically. individual crystals of quartz have dimensions between 5–10 mm. skeletal principal microstructural types prevail in analyzed material (fig. 9). the index parameter im (mineralogical index) was introduced in table 1. it is defined as a ratio of the mass fraction of phyllosilicates and the sum of quartz and calcite. from among the different indices and parameters, im was used to define the proportion of platy (clay) to rotund (massive) particles. the value of im ranges from 0.23 (no. 9) to 2.14 (no. 22). the lowest im is the result of the smallest fracfigure 8: mineral composition of samples (table 1): a-content of minerals, bcontent of massive and fine-grained particles. figure 9: electron micrographs of sample no. 20 (position of sample is presented in fig. 4). geologia croatica 67/2geologia croatica 134 tion of phyllosilicates (16 %). in contrast, sample no. 22 has the highest value of im due to the highest fraction of phyllosilicates (60 %). results of eight shear strength analyses are given in table 1. peak values determined by direct shear are in the range of 23.7°<f<26.1° for peak friction angle and 1<c<9.5 kpa for cohesion. samples were sheared until shear displacement reached 8 mm at each normal stress of 50, 100 and 150 kpa. for the ring shear test, one borehole sample was used and sheared up to 150–200 mm of shear displacement for each normal stress applied (100, 200 and 200 kpa). parameters of residual strength obtained at a cumulative displacement of 450 mm were cr = 16.7 kpa and fr = 16.1°. additional ring shear tests performed on surface samples (no. 19­22) had the following residual strength parameters: cr = 0 kpa and fr = 13.0° – 17.7°. 5. discussion the content of the fine grained fraction increases during rock mass weathering processes. the content of the clay fraction (cf) in the weathered zone also increases by alteration of silicate minerals to clay (selby, 2005).the increase of the cf is clearly visible in samples from colluvium and the weather ing zone, where the clay fraction prevails, while in the flysch bedrock, the silt fraction prevails (table 1). the oxidation of dispersed pyrite that expands in volume and destructs the original structure of the bedrock is usual during weathering processes in rock mass like flysch (attewell & farmer, 1979). furthermore, the palaeogene flysch rock mass in the croatian coast contains a high proportion of the caco3 component. this component is dissolved during weathering processes and the matrix is destroyed which probably causes an increase in the fine grained fractions. in the neighbouring area of the sušačka draga valley, siltstonefrom the flysch bedrock has up to 25 % caco3, while in the weathering zone, the caco3 component decreases to 10–15 % (benac, 1994). results of both methods of grain­size analysis showed that in all the tested samples, fine grained materials prevail, and the cf index ranges between 17–38 %. direct comparison of grain­size fractions is not possible, due to the different methods of analysis. in the sedimentological method of analysis, particles <1 mm are used, and then caco3 is dissolved. therefore, the proportion of the fine fraction (clay and silt) is much higher than in the geotechnical method of analysis (fig. 5). according to the unified soil classification system (uscs), materials are low plasticity clays (cl). results of analysis categorize samples in the zone between kaolinite and illite, which is in accordance with their mineral composition (fig. 6). the uniform relationships between the atterberg limits (which represent the total quantity of pore water and the adsorbed water onto the external and internal surfaces of clay minerals) and other physical properties does not exist in many cases (dolinar & škrabl, 2013). tested samples fall into the area of low (no. 11, 12 and 21) and medium expansion (no. 3, 10, 19, 20 and 22). all of the tested samples have a cf in the range between 17–40% with most of them having clay activity in the range a = 0.5–1 (medium expansion) and some a < 0.5 (low expansion). active clays provide the most potential for expansion. typical values of activities for the three principal clay mineral groups are as follows: a = 0.4 for kaolinite, a = 0.9 for illite and a>1.25 for montmorillonite groups (bell, 1993). therefore, according to activity, the tested samples are in the group of illite and kaolinite (fig. 7).the quantity of adsorbed water on the external surfaces of the clay minerals greatly depends on their size and clay fraction content. the interlayer water quantity depends mostly on the quantity and the type of the swelling clay minerals in the soil composition and their exchangeable cations (grim, 1968). the prevailing gravitational type of sediment transport, which is usual during the sliding process, has a strong influence on the orientation of fine grained particles (lambe & whitman, 1979). according to morphogenesis of slope deposits (benac et al., 2005) the preferred orientation of platy particles and laminar microstructural type could not be expected. the results of analysis using scanning electron microscope illustrate the chaotic texture of particles (fig. 9). grain­size and mineral composition were correlated to geotechnical properties. geotechnical properties of fine­ grained materials which prevail in the lower part of the landslide are mostly unfavourable and often determined by clay minerals (fig. 8).the values of the peak and residual friction angles fr obtained from direct shear apparatus (average 25°) and ring shear apparatus (average 15°) show a difference of 10°. parameters of residual strength obtained for borehole sample (no. 3) and surface samples (no. 19­22) were in the same range regarding the residual friction angle (13.0°< fr <17.7°), but they differed greatly with regard to the value of cohesion. the cohesion determined in ring shear testson samples taken from the surface (for a cumulative displacement of 300–350 mm) was c = 0 kpa, while the borehole sample (no. 3) had an unusually high value of cr = 16.7 kpa (fig. 4, table 1). residual cohesion is often assumed to be cr = 0 kpa, especially after the sample is sheared at large displacements (skempton, 1985). there has been some discussion on the accuracy of this assumption, as cohesion values as large as 9.2 kpa have been observed for residual strength envelopes for some soils (tiwari et al., 2005). most previous studies indicated a reduction in the residual friction angle (fr) with an increase in the clay fraction (cf) (lupini, 1981; tiwari & marui, 2005). many of these studies tried to correlate the residual friction angle of soils with their index parameters. the effect of particle reorientation has an influence only in soils having cf values exceeding 20–25% (skempton, 1985). according to lupini et al. (1981) three modes of shearing have been identified: turbulent (cf < 25 %), sliding (cf > 50%) and one that is transitional between these two. the mineral composition is a key factor controlling the magnitude of fr for soils that exhibit the sliding shear mode. the angles of residual shearbenac et al.: geotechnical properties in relation to grain-size and mineral composition: the grohovo landslide case study (croatia) geologia croatica 135 ing resistance of the three most commonly occurring clay mineral groups are approximately equal to 15° for kaolinite, 10° for illite and 5° for montmorillonite (skempton, 1985). electrostatic bonding has been reported as contributing about 80 % of shear strength for the montmorillonite group, 40–50 % for the illite group and <20 % for the kaolinite group (selby, 2005). the obtained residual friction angles (fr) are in the range of the illite and kaolinite groups, but values disperse due to the wide range in clay fraction (cf) composition of samples. regarding the influence of cf on fr, the data did not show similar trends to those widely reported. samples with the highest cf (no. 21, cf = 37) had the highest residual friction angle (fr = 17.7°). sample no. 22 has the lowest cf value (cf = 19) but the highest fraction of phyllosilicates (table 1; fig. 8). this can be explained by the existence of micritic material and aggregated particles in soils originating from flysch rock mass, which makes it difficult to give any precise relationship between fr and cf (kalteziotis, 1993). soils derived from a rock mass like flysch (marls, mudstones and shales) may generate platy particles by degrading during shearing (lupini et al., 1981). similarly, bonded cohesive soils might exhibit higher residual friction angles than those in the laboratory due to bonding and particle aggregation, which are destroyed when tested in a remoulded state in the laboratory. decalcification during weathering, reduces the calcite content due to the elimination of medium and coarse silt particles and the increase in clay fraction and plasticity index (hawkins & mc donald, 1992). as a result, lower internal friction angle values were obtained in weathered samples compared to the corresponding values in non­weathered samples. the last large landslide occurred after a longer rainy period (benac et al., 1999), and according to historical notes, sliding in the rječina valley often appears after heavy rainfall (vivoda et al., 2012). the stability analyses have indicated that the high water level influences landslide instability (benac et al., 2005). accordingly there are indications that increased saturation of the fine grained particles influences the strength properties on the potential sliding surface. similar conclusions have been drawn for other terrains form ed in a palaeogene flysch rock mass (fifer bizjak & zupančič, 2009; dugonjić jovančević & arbanas, 2012). based on past periodic groundwater measurements and benchmark movements, it was not possible to establish any clear correlation between these two parameters (benac et al., 2005; benac et al., 2011). the establishment of a new monitoring system could provide continuous measurement data (arbanas et al., 2012; mihalić & arbanas, 2013; arbanas et al., 2014). more precise data could be taken from installed vertical inclinometers, long-span extensometers, pore pressure gauges and rain gauges. therefore it will be possible to investigate the influence of water on the strength parameters of fine grained sediments in the investigated slope in the future. 6. conclusions the investigated landside is the biggest known active mass movement in the adriatic coast and is located in the wider unstable zone with numerous traces of dormant landslides. the slopes are at the limit of a stable equilibrium state, and mass movement phenomena have been recorded since the 19th century. quartz, calcite, feldspars and phyllosilicates including micaceous and clay minerals, comprise 86 to 96 % of the mineral composition of the analyzed samples taken from flysch bedrock, the weathering zone and colluvium. the clay fraction ranges from 17 % to 38 % in samples. the most common groups of clay minerals are: kaolinite, illite and chlorite. smectite and vermiculite were found in some samples. clay activity of the tested samples is from 0.45 to 0.89. this is in the range of low to normally active clays and corresponds to kaolinite and illite groups. the results of analysis using scanning electron microscope presented the chaotic microstucture of particles that corresponds to the morphogenesis of the investigated slope. the residual friction angle is in the range 13.0°<fr<17.7° and corresponds to kaolinite and illite groups. preformed stability analyses have shown that slope move­ ments were caused by an increase in groundwater level and thereby unfavourable water flow. according to the described laboratory analyses, silty­clayey sediments prevail in the lower part of the colluvium materials in the landside body. mineral composition and decrease in strength of fine grained soil materials due to increase of pore water quantity, contributes to the slope movements. aknowledgment the authors would like to express their sincere gratitude for scientific contribution of professor vladimir jurak (decreased), who provided the initiative for this investigation, and to acknowledge support of the university of rijeka in two research projects: “geological hazard in the kvarner area”and “development of the landslide monitoring and early warning system for the purpose of landslide hazard mitigation”. references arbanas, ž., jagodnik, v., ljutić, k., dugonjić jovan če­ vić, s. & vivoda, m. (2012): establishment of the grohovo land slide monitoring system.– proceedings of the 2nd project work shop: monitoring and analyses for disaster mitigation of landslides, debris flow and floods. book of proceedings, građevinski fakultet u rijeci, rijeka, 29–32. arbanas, ž., kyoji, s., jagodnik, v., vivoda, m., dugonjić jo vančević, s. & peranić, j. (2014): landslide monitoring and early warning system using integration of gps, tps and conventional geotechnical monitoring methods.– proceedings of the 3rd world landslides forum, beijing, june 2014 (in press). attewell, p.b. & farmer, i.w. (1979): principles of engineering geology.– chapman and hall, london, 1045 p. bell, f.g. (1993): engineering geology.– blackwell science, cambridge, 358 p. geologia croatica 67/2geologia croatica 136 benac, č. (1994): engineering geologic characteristic of the coastal ad submarine zone of rijeka bay (in croatian).– unpublished phd thesis, rudarsko­geološko­naftni fakultet, zagreb. benac, č., arbanas, ž., jardas, b., kasapović, s. & jurak, v. (1999): složeno klizište u dolini rječine (complex landside in the rječina river valley – in croatian).– rudarsko­geološko­naftni zbornik, 11, 81–90. benac, č., arbanas, ž., jardas, b., jurak, v & kovačević, s.m. (2002): complex landslide in the rječina river valley (croa­ tia): results and monitoring.– in: ribar, i, stemberk, j. & wag ner, p. (eds.): landslides. proceedings of the 1st european conference on landslides, prague, june 2002. a.a.balkema, lisse­abingdon­exton­tokyo, 487–492. benac, č., jurak, v., arbanas, ž., oštrić, m. & ožanić, n. (2005): complex landslide in the rječina river valley (croatia): origin and sliding mechanism.– bulletin of engineering geology and the environment 64/4, 361–371. benac, č., jurak, v., oštrić, m. & ožanić, n. (2006): qualitative assessment of geohazard in therječina valley, croatia.– proceedingsof the 10th iaeg international congress: iaeg engineering geology for tomorrow’s cities, the geological society of lon don, 658 (1–7). benac, č., dugonjić, s., arbanas ž., oštrić, m. & jurak, v. (2009): the origin of instability phenomena along the karst­ flysch contacts.– in: vrkljan, i. (ed.): isrm international symposium rock engineering in difficult ground conditions: soft rock and karst, cavtat, october 2009. crc press, boca raton­london­ new york­leiden, 757–761. benac, č., dugonjić, s., vivoda, m., oštrić, m. & arbanas, ž. (2011): a complex landslide in the rječina valley: results of monitoring 1998–2010.– geologia croatica, 64/3, 239–249. doi: 104154/gc.2011.20 blašković, i. (1999): tectonics of part of the vinodol valley within the model of the continental crust subduction.– geologia croatica, 52/2, 153–189. dolinar, b. & škrabl, s. (2013): atterberg limits in relation to other properties of fine­grained soils.– acta geotechnica slovenica, 2013/2, 1–13. dugonjić jovančević, s. & arbanas, ž. (2012): recent landslides on the istrian peninsula, croatia.– natural hazards, 62/3, 1323–1338. doi 10.1007/s11069­012­0150­4 fifer bizjak, k. & zupančič, a. (2009): site and laboratory inve­ stigation of the slanoblato landslide.– engineering geology, 105, 171–185. doi:10.1016/j.enggeo.2009.01.006 grim, r.e. (1968): clay mineralogy.– mcgraw­hill book, new york, 370 p. hawkins, a.b. & mcdonald, c. (1992): decalcification and residual shear strength reduction in fuller’s earth clay.– géotechnique, 42/3, 453–464. hoek, e. & marinos, p. (2001): estimating the geotechnical properties of heterogeneous rock masses such as flysch.– bulletin of engineering geology and the environment, 60/2, 85–92. iaeg (1990): suggested nomenclature for landslides.– bulletin of engineering geology and the environment, 41, 13–1. igh (2000): sanacija klizišta uz korito rječine (ii faza istraživačkih radova).– izvještaj o inženjerskogeološkim i geomehaničkim istraži­ va njima, rijeka. kalteziotis, n. (1993): the residual shear strength of some helle­ nic clayey soils.– geotechnical & geological engineering, 11/2, 125–145. korbar, t. (2009): orogenic evolution of the external dinarides in the ne adriatic region: a model constrained by tectonostratigraphy of upper cretaceous to paleogene carbonates.– earth­science reviews, 96, 296–312. doi: 10.1016/j.earscirew.2009.07.004 lambe, w.t. & whitman, r.v. (1979): soil mechanics, si version.– yohn wiley & sons, new york­chichester­brisbane­toronto, 553 p. lupini, j.f., skinner, a.e. & vaughan, p.r. (1981): the drained residual strength of cohesive soils.– géotechnique, 31/2, 181–213. marinčić, s. (1981): eocenski fliš jadranskog pojasa [eocene flysch of adriatic belt – in croatian].– geološki vjesnik, 34, 27–38. mihalić, s. & arbanas, ž. (2013): the croatian­japanese joint research project on landslides: activities and public benefits.– in: sassa, k. (ed.): landslides: global risk preparedness. heidelberg, springer, 345–361. selby, m.j. (2005): hillslope materials and processes (2.ed).– oxford university press, oxford, 451 p. skempton, a.w. (1985): residual strength of clays in landslides, folded strata and the laboratory.– géotechnique, 35/1, 3–18. tiwari, b. & marui, h. (2005): a new method for the correlation of residual shear strength of the soil with mineralogical composition.– journal of geotechnical and geoenvironmental engineering, 131/9, 1139–1150. tiwari, b., brandon, t.l., marui, h. & tuladhar, g.r. (2005): comparison of residual shear strengths from back analy­ sis and ring shear tests on undisturbed and remolded specimens.– journal of geotechnical and geoenvironmental engineering, 131/9, 1071–1079. tziallas, g.p., saroglou, h. & tsiambaos, h. (2013): determination of mechanical properties of flysch using laboratory methods.– engineering geology, 166, 81–89. doi: org/10.1016/j.enggeo. 2013.09.002 vivoda, m., benac, č., žic, e., đomlija, p. & dugonjić­jo­ van čević, s. (2012): geohazard u dolini rječine u prošlosti i sadašnjosti [geohazard in rječina river valley in past and present – in croatian].– hrvatske vode, 20, 105–116. manuscript received february18, 2014 revised manuscript accepted april 15, 2014 available online june17, 2014 www.geologia-croatica.hr abstract the bor metallogenic zone is one of the most important metallogenic units in the republic of serbia. volcanic processes in this unit are characterized by the domination of extrusive volcanic activity, and the change of depositional environment during the numerous volcanic cycles, as well as facial transitions and huge deposition of synand post eruptive resedimented volcanoclastics. the predominant metals in the bor metallogenic zone are copper and gold, accompanied by iron, base-metals, silver, molybdenum, and minor platinumgroup elements. the most prominent morphogenetic types of deposit comprise porphyry copper-gold, cupriferous pyrite, massive base-metal sulphides and hydrothermal veins, iron oxides skarns, carbonate replacement polymetallic deposits, volcanogenic epithermal gold mineralization of the high sulphidation type, and exceptionally rare clasts of copper sulphide ore mechanically accumulated in small sedimentary basins filled by pyroclastics. the total production of the bor metallogenic zone since 1902 has been near 652 mt of ore with 4.93 mt of copper and 280 tons of gold. mineral resources of the bor metallogenic zone are estimated at over 20 millions of tons of copper and 1,000 tons of gold. the main geological characteristics of selected metallic mineral deposits in this area are described in this paper. keywords: bor ore deposits, bor-srednogorie metallogenic zone, porphyries and related mineralizations, copper, gold, resources, reserves article history: received december 09, 2015 revised and accepted january 22, 2016 avaliable online february 29, 2016 1. introduction the bor metallogenic zone senso stricto belongs to the borsrednogorie metallogenic zone which is a part of the tethyan eurasian metallogenic belt (temb) (janković, 1976). this the alpine-balkan-carpathian-dinaride geodynamic province (abcd) is a part of the alpine-himalayan orogenic system that extends from western europe to south east asia (heinrich & neubauer, 2002; schmid et al., 2008). the orogen resulted from the convergence and collision of the indian, arabian, and african plates with the eurasian craton, initiated in the middle jurassic, through the cretaceous time, and continuing until the present (borojević šoštarić et al., 2014; palinkaš et al., 2008). the structural setting of the region reflects large-scale oroclinal bending during post-collision tectonics throughout the tertiary including major transcurrent fault systems with an overall dextral displacement in excess of 100 km (kräutner & krstić, 2002). the most significant segment of the temb economically comprises the upper cretaceous subduction related magmatic rocks and mineral deposits, referred to as the banatitic magmatic and metallogenic belt (bmmb) (berza et al., 1998) or the apuseni-banat-timok-srednogorie belt (zimmerman et al., 2008). the bmmb intrusives and dominant extrusive rocks were emplaced during a 30-million-year period from ~90 ma to 60 ma and may have been the result of complex tectonic and magmatic emplacement melting. the bor-srednegorie metallogenic zone as a part of the carpatho-balkan metallogenic province extends from lilieci linbcova and bozovici in the north, over bor to burgas, proceeding into the black sea and tracia in turkey (janković, 1980, 1990, 1997). it is over 600 km long and up to 20 km wide (janković et al., 2003). the easternmost magmatic complex in the serbian part of the belt is the timok magmatic complex (tmc) (banješević, 2006). volcanic processes in the tmc are characterized by the predominance of extrusive volcanic facies, and the change of depositional environment during the volcanic cycle, as well as facial transitions and heavy deposition of synand post eruptive resedimented volcanoclastics. magmatic activity generally progresses from east to west. magmatism lasted continuously for 10 ma starting in the upper turonian (the oldest andesitic rock is 89 ma) till upper campanian (clark & ullrich, 2004). the age of the valja strž plutonites is 78 ma (banješević, 2006). copper and gold/silver, accompanied by iron (sulphide, oxide) and base-metals, molybdenum, sporadically pge, are the predominant metals in the bor metallogenic zone. the most prominent morphogenetic types of deposits are porphyry copper / gold, cupiferous pyrite, massive base-metal sulphides, and hydrothermal veins, skarns of iron oxides, skarns of leadzinc sulphides, volcanogenic epithermal gold mineralization of high sulphidation type, and exceptionally clasts of copper sulphide ore mechanically accumulated in the small sedimentary basin infilled with pyroclastics. the ore deposits are grouped into several ore fields and districts, each characterized by some specific genetic features. 143-155 14 figs. 2 tabs. doi: 10.4154/gc.2016.11 the mineral resources of the bor metallogenic zone: a review rade jelenković1, dragan milovanović2, dejan koželj3 and miodrag banješević4 1belgrade university, faculty of mining and geology, đušina 7, belgrade, serbia (rade.jelenkovic@rgf.bg.ac.rs) 2belgrade university, faculty of mining and geology, đušina 7, belgrade, serbia (milovdr@beotel.net) 3rakita exploration d.o.o. bor, cara lazara bb, 19210 bor, serbia (dejan_kozelj@fmi.com) 4balkan exploration and mining d.o.o. 11000 belgrade, serbia (miodrag@reservoirminerals.com) 144 vol. 69/1 2. upper cretaceous magmatic suites of the timok magmatic complex in the bor metallogenic zone the volcano-intrusive complexes are represented by volcanic, volcano-sedimentary and plutonic rocks (fig. 1). they derived from subcrustal, contaminated magma(s), as have been suggested by karamata & djordjević (1980). the 87sr/86sr ratio ranges from 0.707 to 0.712. the calc-alkaline series is prevalent with respect to tholeiite rocks. volcanic rocks formed within three stages during the upper cretaceous. they are of andesitic composition, while dacite occurs sporadically. the plutonic granitoids correspond to composite complexes (from gabbro to diorite, monzonite and granodiorite). in this zone we can recognize: timok andesite (at) the timok andesites, predominantly amphibole andesite and high potassium trachyandesites, occur in the eastern parts of the tmc, where they overlie cenomanian and turonian sediments (drovenik, 1959; đorđević & banješević, 1997; ljubovićobradović et al., 2011, banješević, 2015). they are covered by senonian sediments (oštrelj sediments and bor clastites) and the metovnica epiclastite (banješević, 2015). amphibole andesites and trachyandesites characterized by high potassium predominate. according to their lithological, volcanological and petrographic characteristics (banješević, 2010), the andesites are distinguished into the following facies: lava flows (coherent and autoclastic), shallow intrusions (lava domes, dykes and sills) and various volcaniclastic rocks. volcanic activity was predominantly subterrestrial in an earlier volcanic phase and subaerial to submarine in a later volcanic phase. high precision u/pb zircon and 40ar/39ar dating, confirms ages from 89.0±0.6 to 84.26±0.67 ma (upper turonian to upper santonian). metovnica epiclastite (em) the metovnica epiclastite developed in the eastern part of the tmc in a shallow marine environment, infilling rough volcanic bedrock topography (đorđević & banješević, 1997, đorđević, 2005). the rocks are coarseto fine-grained, massive, coarsely banded, sometimes even laminated. they are composed of texturally and structurally different fragments deriving from different volcanic facies of the timok andesite. the dominant type of transport processes are debris to grain flows. the em are often interbedded with the oštrelj sediments. sometimes, the rocks contain a very well preserved coniacian– campanian microfauna (đorđević & banješević, 1997; đorđević, 2005). osnić basaltic andesite (ao) and ježevica andesite (aj) the rock suite corresponding to andesite – basaltic andesite of calc-alkaline to tholeiitic character can be distinguished among the senonian volcanic rocks of the tmc. the first group includes pyroxene basaltic andesite (ao), while the second group comprises amphibole andesite (aj). both rock suites are located in the central and western parts of the tmc and are sometimes closely associated. these volcanic rocks are both underlain and overlain by oštrelj sediments or the vrbovac reef, respectively (banješević, 2015). the amphibole andesites are most frequently massive rocks. the chemical composition of the minerals is very simi lar to the pyroxene-bearing varieties, except that the plagioclases are more basic in the latter. the volcanic rocks predominantly occur as lava flow facies (autobreccias and hyaloclastic breccias) and resedimented volcaniclastic deposits. lava flow facies are up to several metres thick, while their length reaches several hundred metres. the resedimented volcanoclastites are mostly stratified volcaniclastic rocks, psammitic to psephitic, of different origins and types of transport. volcanic activity is predominantly effusive, rarely explosive. eruptions are linear and mostly, randomly distributed, initiating the formation of volcanic islands. volcanism took place terrestrially as well as in a submarine environment. the u/pb zircon dating of ao and aj suggests ages ranging between 80.8 to 82.27±0.35 ma confirming a santonian– lower campanian age (banješević et al., 2006; kolb et al., 2013). valja strž plutonite (pvs) the plutonite occur at the western margin of the tmc. the rocks are grey to dark-grey in colour, of hypidiomorphic granular texture and massive structure, sometimes showing rectangular jointing (majer, 1953). they range in composition from monzodiorite and monzonite to diorite, q-diorite, granodiorite, syenite and rare gabbro. this hypabyssal rock intruded into ao and aj. figure 1. a simplified geological map of the timok magmatic complex. legend: 1. bor clastites, 2. vrbovac reef, 3. boljevac latite, 4. valja strž plutonite, 5. osnić basaltic andesite and ježevica andesite, 6. metovnica epiclastite, 7. oštrelj sediments, 8. timok andesite, 9. lenovac clastites, 10. tmc basement rock, 11. neogene and quaternary sediments. 145 jelenković et al.: the mineral resources of the bor metallogenic zone: a review fi gu re 2 . m et al lo ge ni c un its , o re d ep os its a nd s ig ni fic an t m et al lic m in er al o cc ur re nc es o f t he b or m et al lo ge ni c zo ne : ( i) m aj da np ek o re d is tri ct : i -1 t ilv a to m a or e fie ld : o cc ur re nc es 1 . is en ja , 2 . s re dn ji b ig er p ot ok , 3 . v el ik i u je va cb ig er , 4 . b ig er p ot ok , 5 . p ot oj č uk ab ig er po to k de po si t, 6. m al i u je va c1, 7 . m al i u je va c 2, 8 . p oj av a 1. i2 m aj da np ek o re fi el d: 9 . m aj da np ek -t en ka d ep os it, 1 0. š va jc , 1 1. v al ja f un da ta , 1 2. š aš ka re ka , 1 3. m al a r av na re ka , 14 . v al ja m as ta ka , 15 . v al ja l om it, 1 6. v al ja p re ra st , 1 7. v el ik i v al ja p re ra st . i -3 v la ol eja si ko vo o re fi el d: 1 8. o ga šu š uć ur e, 1 9. d ur la n po to k de po si t, 20 . č ok a m ar in d ep os it, 2 1. c ig an sk i p ot ok -l ak z on e (o cc ur re nc es : 1 , 2 , 3 ), 22 . c ig an sk i p ot ok , 2 3. m al i k ur tu ra z, 2 4. k or ne t, 25 . o ga šu p eš te ri, 2 6. p og ar u o gr ad a. (i i) b or o re d is tri ct : i i1 m al i k riv el j-c er ov o or e fi el d: 2 7. f ra nk ul ja c, 2 8. s trn ja k, 2 9. k ut i, 30 . c er ov o de po si t ( c er ov opr im ar no an d c er ovo -c em en ta ci ja ), 31 . k ra ku b ug ar es ku – c em en ta ci ja d ep os it (c em en ta ci ja : c 1, c 2, c 3 an d c 4) , 3 2. b ig er p ot ok , 3 3. m al i k riv el j d ep os it, 3 4. k iri dž ijs ki p ot ok , 3 5. č ok a č ur ili , 3 6. u jo va re ka . i i2 ve lik i k riv el j o re fi el d: 3 7. v el ik i k riv el j d ep os it. ii -3 b or o re fi el d: 3 8. b or d ep os it, 39 . r uk ja vi ca . i i4 b re st ov ac o re fi el d: 4 0. b re st ov ac , 4 1. č uk ar u pe ki d ep os it. ii -5 m et ov ni ca gr ou p of o cc ur re nc es : 4 2. m ar ko v po to k, 4 3. jo va no vo b rd o, 4 4. s uv a re ka , 4 5. k am en i p ot ok , 46 . d os ul m ar e, 4 7. d ra gi na č uk a, 4 8. p ap ar ko v po to k, 4 9. m iš lje no va c, 5 0. g os ko vo p ot ok . in di vi du al o cc ur re nc es 5 1. r av na re ka , 5 2. o ga šu re u, 5 3. c rn a re ka . ( ii i) c rn i v rh o re d is tri ct : i nd iv id ua l o cc ur re nc es : 5 4. v el ik i p ot ok , 5 5. o ga šu p iš to lj, 5 6. ja si ko vo , 5 7. ja gn jil o, 5 8. m us ta c rn a re ka , 5 9. o ga šu š uj ku , 6 0. č ok a r eu , 6 1. o m an ilo r, 62 . č ok a šk ro lo pu j, 63 . č ok a žu m er i, 64 . l ip uc a. i ii -1 c rn i v rh o re fi el d: 6 5. č ok a b ač ilo , 6 6. o m an , 6 7. v al ja s ak a de po si t, 68 . č ok a fr as en , 6 9. d um itr u po to k de po si t, 70 . č ok a r ak ita , 7 1. č ok a b ar be š – o ga šu k un uk u – o ga šu r eš , 7 2. v ro ko lu ce , 7 3. k ra ku p et ru nj – k ra ku l un g, 7 4. v al ja s trž d ep os it, 75 . l ip a de po si t, 76 . k up in ov o, 7 7. č ok a k up ja tra , 7 8. p ja tra r oš , 7 9. c rv en a re ka , 8 0. v al ja k rž an , 8 1. c rn a re ka , 8 2. s us ul a. ii i2 ti lv a n ja gr a or e fie ld : 8 3. t ilv a k um us ta ka , 8 4. b el je vi na d ep os it, 8 5. z la će d ep os it, 8 6. t ilv a n ja gr a, 8 7. g al on ja p ot ok . i ii -3 z lo t g ro up o f o cc ur re nc es : 8 8. u go sk ur p ot ok , 8 9. k rli na c, 9 0. v al ja k u fr as ej , 9 1. z lo t. in di vi du al o cc ur re nc es : 92 . t ilv a k ud ru m u, 9 3. p un đi lo v po to k, 9 4. p at ra no v po to k, 9 5. a nđ an ov p ot ok . ( iv ) m ar ko v ka m en – g ra di št e or e di st ric t: iv -1 m ar ko v ka m en – s av in ac o re fi el d: 9 6. s av in ac d ep os it, 97 . v el ik o bl at o, 9 8. m ar ko v ka m en . i v2 g ra di št e gr ou p of o cc ur re nc es : 9 9. j ež ev ic a, 1 00 . d ub ok i p ot ok , 1 01 . g ol em a re ka , 1 02 . g ra ni če , 1 03 . m eč ji vi s – o rlo vo b rd o 1, 1 04 . m eč ji vi s – o rlo vo b rd o 2, 1 05 . m eč ji vi s – o rlo vo b rd o 3, 1 06 . m eč ji vi s – o rlo vo b rd o 4, 1 07 . a rš ic a, 10 8. m eč ji vi s, 10 9. š iro ko p ol je , 1 10 . n av od na s tra na , 1 11 . b uk ov a gl av a. in di vi du al o cc ur re nc es : 1 12 . l as ov o, 1 13 . š um la tic a, 1 15 . c ep e. ( v ) po ta j č uk a – ti sn ic a or e di st ric t: 11 5. k or ka n de po si t, 11 6. b ig ar h ill d ep os it, 1 17 . k ra ku p eš te r d ep os it, 1 18 . k or ka n ea st d ep os it. 146 vol. 69/1 according to u/pb zircon analysis, the age of the valja strž plutonite is 78.62±0.44 ma, (upper campanian), determined by von quadt et al. (2002). boljevac latite (lb) numerous latitic dykes occur along the western border of the tmc. these rocks cross-cut the ao and the aj. they appear in the form of shallow intrusions (dykes, sills and veins), seldom as lava flows. they are usually small masses, up to several tens of metres long and 3 to 4 metres thick. the rocks are dark-grey, showing very distinctive textures characterized by large, elongated phenocrysts of plagioclase and potassium feldspar, which sometimes exhibit fluid orientations. the texture is fine-grained, very fine-grained or hypocrystalline porphyrithic with a microcrystalline, intersertal and pilotaxitic groundmass. the latites consist of plagioclase, potassium feldspar, clinopyroxene and various accessory minerals (milovanović et al., 2005). the latite cross-cut the ao and aj, however their age is poorly constrained. hydrothermal alteration zones are significant characteristics of the timok magmatic complex. they occupy an area of about 164 km2 and represent one of the most important geological criteria in prospecting and exploration of copper and gold mineralization (fig. 2). very frequently hydrothermal alterations (potassic – quartz, potassium feldspar, biotite, anhydrite; phyllic – quartz, sericite, pyrite; argillic – quartz, kaolinite, alunite, zunite, neobiotite; propylitic – chlorite, epidote, carbonate) show zonality, the intensity of which weakens with distance from the porphyry intrusions. argillic and propylitic alterations are located in the peripheral part of hydrothermally altered and mineralized zones. predominant hydrothermal alterations are silicification and pyritization, accompanied by chloritization and less frequently argillization. they are not always ore-bearing and their formation is related partly to the action of volcanic vapours and gases and is not accompanied by hydrothermal solutions. hydrothermally altered rocks, containing mineralization, are usually of small dimensions and show an increased content of the main (cu, au) and accompanying (ag, mo) elements. 3. metallic mineral resources of the bor metallogenic zone there are 22 registered metallic mineral deposits and 96 significant mineral occurrences within the bor metallogenic zone. all of them are located in 5 ore districts including 10 ore fields and 3 separate groups of mineral occurrences (fig. 2). base metals (cu, pb-zn), precious metals (au, ag) and some other metals (fe), have been more thoroughly explored and their resources have been augmented, so that they still represent, in spite of numerous problems attending their exploitation, the potential for development for serbia. the metallic mineral resources of the bor metallogenic zone are grouped as follows: a) metallic mineral resources with economically significant reserves, which are currently being exploited, are already provided with processing capacities, and which continue to be the basis of the industrial development of the country. the basic characteristics of these deposits are predominantly low metal content and substantial ore potential. currently 4 cu deposits are in operation: majdanpek, veliki krivelj, bor system and cerovo. b) identified mineral resources, which are beings exploited, or mineral resources occurring in minor quantities, sufficient for short periods of production (e.g. čoka marin etc). c) potentially significant, partially defined metallic mineral resources, the value of which depends on technical-economic parameters (au mineral deposits: korkan, bigar hill and others; cu deposits: mali krivelj and others). d) mineral resources likely to be found in the bor metallogenic zone. the metallogenic analyses and up-to-date geological exploration undertaken show that new resources of copper and gold are located in serbia (porphyry copper-gold and related epithermal cu-au deposits /čukaru peki deposit, and sediment-hosted gold deposits). 4. styles of ore mineralization, associations of minerals and elements the bor metallogenic zone and adjacent segments host a range of endogene mineral deposits. the most significant are: figure 3. schematic cross section through the timok magmatic complex showing the location of different types of metallic mineral deposits. 147 jelenković et al.: the mineral resources of the bor metallogenic zone: a review commodity genetic type morphology structuraltextural variety mineral paragenesis cu (%) au (g/t) examples cu-au porphyry copper deposits s, iel, vez s-d py, cpy, mg, mo 0.1–0.7 0.07–0.25 majdanpek locally 1 g/t hydrothermal volcanogenic deposits s, l, i m-s, v-i py, en, chl, co, bo, cpy, sph, ga 1.0–7.0 0.8–3.0 bor, lipa v m-s, i-c, i py, en, te, bo, cpy 0.1–0.64 0.1–0.7 kraku bugaresku ore clasts l m-s py, co, en, chl, bo, cpy 3.5 5.4 novo okno au high sulphidation l d el, nau, au-tl, en, lu, chl, co, sph, ga 0.84 hydroquartzite s, c m-s, d 2.1–3.3 2 tilva mika, m, n s, c v, v-i 0.66–1.0 kamenjar v, l m-s 0.1–3.4 čoka kupjatra vez m-s, v-i 0.1-2 root parts of tilva roš low sulphidation v, i m-s el, nau, py, sph, cpy 3–23 zlaće sedimenthosted i, l, v i, v py 0.8–1.3 bigar hill pb-zn, ag skarn i, l m-s, s-d ga, sph 0.21 valja saka cu, au skarn i, l m-s, s-d cpy, py 0.21 beljevina fe skarn i, l m-s, s-d mg 0.21 potoj čuka table 1. the main groups of metallic mineral deposits in the bor metallogenic zone senso stricto. porphyry cu-au deposits and related high sulphidation cuau mineralization, skarn and contact-replacement deposits (fe, pb-zn, cu-au etc), vein deposits (cu, cu-au), mechanically redeposited cu-au deposits and sediment-hosted deposits (fig. 3). according to morphogenetic types and mineral paragenesis, one can differentiate the following groups of deposits (table 1). the associations of elements concentrated in the previously mentioned ore deposits include: a) major elements: cu, au, mo, fe (py) ± pb-zn; b) trace elements, recoverable: se, pge, ag, cd and c) trace elements, unrecoverable: w, sn, bi, sb, as, (ba). the principal associations of elements are classified as follows: a) cu, au, mo ± ag, pge (porphyry copper); b) cu, pb/zn, fe (py), au/ag ± se, bi, sb (massive sulphide); c) cu, au, fe (py), as ± w, sn, se, sb (cupriferous massive sulphide/replacement); d) fe-s (massive pyrite); e) cu, fe (py) ± mo, bi, w and pb-zn-ag ± cu-au (skarn); f) sediment-hosted: au, fe. 5. the present state of the selected metallic mineral resources the most significant metallic mineral resources of the bor metallogenic zone are copper, gold, lead-zinc and iron. 5.1. copper mineral resources copper mineral resources of the bor metallogenic zone are classified as follows: a) porphyry cu and cu-au, b) hydrothermal volcanic mineral resources of copper-bearing pyrites, c) volcanogenic polymetallic hydrothermal mineral resources of cu-pb-zn massive sulphides, d) polymetallic cu-pb-zn mineral resources with a high contribution of gold, e) skarn mineralization and f) mechanically redeposited cu-au mineral resources. porphyry copper deposits (pcd) contain the highest concentrations of copper and gold and show common characteristics corresponding to a general model of porphyry copper systems. the differences and unique features exhibited by individual deposits reflect local variability. ore mineralization is confined to shallow emplacement of porphyritic dykes (quartz diorite, granodiorite and/or monzonite porphyritic). the spatial relationship of the plutonic intrusion and porphyry copper mineralization is either evident (crni vrh) or assumed on the grounds of the development of porphyry dyke suites (majdanpek, borska reka, veliki krivelj). porphyry copper deposits are classified as follows: a) pcd related to diorite porphyry cluster (valja strž); b) pcd related to high-level dyke swarms above the plutonic body (veliki krivelj), c) pcd associated with high sulphidation massive sulphides (subvolcanic type, bor–borska reka) and d) pcd abbreviations: 1) morphology: c: column, i: irregular, iel: irregularly elongated lenses, l: lense, s: stock, v: vein, vez: very elongated zones. 2) structural-textural variety: i: impregnations, i-c: irregular clusters, m-s: massive sulphides, o-v: ore veins, s-d: stockwork–disseminate, v-i: veinlets-impregnation. 3) minerals: au-tl: au-telluride, bo: bornite, chl: chalcocite, co: covellite, cpy: chalcopyrite, el: electrum, en: enargite, ga: galena, lu: luzonite, mg: magnetite, mo: molybdenite, nau: native gold, py: pyrite, sph: sphalerite, te: tetrahedrite. 148 vol. 69/1 controlled by fault structures with subvolcanic intrusions of upper cretaceous andesites and hypabisal intrusions of granodiorite porphyrites, diorite porphyrites and, locally, granodiorites. pcds related to diorite porphyry cluster are located in the western part of the tmc. ore mineralization is hosted by andesites and the valja strž granitoid complex which composition changes from monzonite granitoids up to diorites. hydrothermal alteration of andesites and granitoids are characterized by biotitization, silicification and pyritization, partly by kaolinization and epidotization. porphyry copper mineralization has been formed most probably in one stage and it corresponds to the ortogenetic model of porphyry copper mineralization. valja strž, dumitru potok, dumitru potok east and čoka rakita porphyry au-cu deposit belong to this group of porphyry copper deposits and mineral occurrences (fig. 4). pcd formed in the domain of dyke systems above magmatic complexes are localized in hydrothermally altered upper cretaceous andesites and pyroclastites as well as in volcano-sedimentary rocks, which were penetrated by numerous quartz-diorite porphyry (veliki krivelj deposit) (fig. 5). the copper-bearing mineralization also comprises previously formed skarns and quartz-diorite-porphyry and andesite dykes. facies of hydrothermal alterations comprise biotitization which laterally changes into seritization, silicification and pyritization in the rim parts of the ore bodies. in the deeper parts of deposits, there is also a local distribution of intensive sulphatization. mineral associations comprise chalcopyrite, pyrite, scarcely molybdenite (50-150 ppm), pyrrhotite, magnetite, haematite, traces of enargite, galena and sphalerite. gangue minerals are quartz and less often calcite, barite, siderite, while fluorite may be observed only in exceptional cases. a specific subtype of the previously described mineralization is located in the cerovo – mali krivelj ore field (fig. 6). the clearly expressed relationship of the ore mineralizations with quartzdiorite porphyry dykes in the veliki krivelj deposit is not confirmed in this case. the geological setting of the ore zone is a complex one. it is composed of lower cretaceous sediments, hydrothermally altered intrusive rocks and a volcano-sedimentary series. intensive kaolinization and pyritization are frequently accompanied by silicification. the majority of deposits show mutually separated characteristic zones: a) oxidation zone, and b) secondary sulphide enrichment zone. dominant minerals are chalcocite and covellite. chalcocite formed from chalcopyrite and pyrite, then covellite which frequently occurs with chalcocite but is less distributed and mainly formed by pseudomorphosis after chalcopyrite, pyrite and magnetite. molybdenite, sphalerite and galena are rare. pcd associated with high sulphidation system of massive sulphide mineralization is recognized in the bor copper-gold deposits (i.e. bor system). along a subvertical volcanic structure, the length of which exceeds 2 km, porphyry copper mineralization is localized at depth (i.e. the borska reka deposit), and above is well-developed high sulphidation system involving cupriferous pyrite ore (fig. 7). porphyry copper mineralization is related to hydrothermally altered hornblende-biotite andesite and their pyroclastites intruded by quartz diorite porphyry dykes. mineralization is associated with potassium silicate alteration, neobiotite, diaspore, gypsum, anhydrite, alunite and to a propylitic assemblage with widespread illite and chlorite. in the uppermost parts of the borska reka deposit, advanced argillic alteration coupled with intense pervasive silicification, marks upwards grading into a transition zone of previously developed high sulphidation mineralization. fault structures in the borska reka deposit are the most prominent structural forms. the extensive dislocation of a nw-se strike, known as the bor fault, have brought the volcanoclastites into contact with the bor conglomerates. the e-w figure 4. cross-section through the valja strž porphyry copper deposit showing alteration and mineralization (2010)1. figure 5. cross-section through the veliki krivelj porphyry copper deposit (janković et al., 2003) 1) ore mineralization, 2) limestones, skarns, 3) andesites, 4) quartzdiorite porphyry dykes, 5) hydrothermally altered andesites, 6) fault, 7) drill-holes. 1dundee precious metals (2010): timok project, serbia national instrument 43-101 technical report prepared by coffey mining pty ltd on behalf of: rodeo capital corp. 2010, 255 p. retrieved from: http://www.avalaresources.com/i/pdf/technical-report-timok-project-serbia.pdf. 149 jelenković et al.: the mineral resources of the bor metallogenic zone: a review striking faults that cross-cut the bor fault have also been recorded. fractures and fissures, mainly filled with alteration products and sulphide minerals, are widespread within the deposit. the mineral composition of porphyry copper mineralization is complex: the main components are magnetite (1%), haematite, rutile, pyrite, chalcopyrite, bornite, molybdenite, covellite, chalcocite and digenite. the most extensive are pyrite and chalcopyrite, subsidiary bornite, chalcocite and covellite, while other minerals occur included in pyrite. oxides of titanium and iron are accessory components of the host rocks. the gold content in the shallow parts of the deposit is higher (0.7 – 1.0 g/t) than in the deeper parts (~0.25 g/t). pcd related to fault structures together with massive pyrite, and pb-zn sulphides are rare in the bor metallogenic zone (majdanpek deposit, fig. 8). it is formed along a very narrow (only 300 m wide) and elongated 5 km long fault zone in which andesites and dykes of quartzdiorite porphyry are wedged at the contact of the jurassic and cretaceous limestones and cambrian gneisses and amphibolites. the majdanpek deposit consists of several types of mineralization formed in multistage processes: dominant porphyry copper-gold mineralization with molybdenite, massive sulphide, pyrite bodies, skarn magnetite and hydrothermal pb-zn sulphides in the form of massive-metasomatic bodies and ore veins. hydrothermal volcanic deposits of copper bearing pyrite (or, volcanogenic cupriferous pyrite deposits) are localized in andesites. the advanced argillite alteration prevails, and the mineralization suggests ore deposition under a high sulphur fugacity. the predominant metals and metalloids are cu, au, fe and as. the w, sn and se mineralizations have also been recorded. ore bodies of massive sulphides and stockworkdisseminated type of mineralization in the bor deposit, and in the brestovac ore field (čukaru peki cu-au deposit) belong to this type of ore deposit (fig. 9). the genetic model of mineralization in both deposits is very similar. it includes different styles of porphyry cu-au and high epithermal mineralization (fig. 10). the mineralization identified at the čukaru peki deposit belongs to the epithermal and porphyry copper-gold types (banješević & large, 2014). it occurs at depths between 400 m below the surface to greater than 2 km. the host rocks are upper cretaceous hornblende and hornblende biotite andesites, andesite breccias, hydrothermal breccia, and relatively rare diorite porphyry. three styles of mineralization are defined at čukaru peki: 1) high sulphidation type, comprising cu-au massive-sulphide, veins, stockwork and hydrothermal breccia matrix sulphide. this type of mineralization forms a single zone at depths ranging from 400 to over 1000 m below the surface. the predominant sulphides are covellite with bornite, enargite and chalcocite. dominant alteration mineralogy is typical advanced argillic, including quartz, alunite, dickite and kaolinite. 2) porphyry type of mineralization in the deeper parts of the čukaru peki deposit, at depths greater than about 1000 m. figure 6. cross-section through the cerovo copper deposit (janković, 1990). figure 7. cross-section through the borska reka porphyry copper deposit (simić & mihajlović, 2006)2. 1) pelite, 2) hornblendeaugite andesite, 3) hornblende-augite andesite pyroclasts, 4) hornblende-biotite andesite, 5) hydrothermally altered hornblende-biotite andesite, 6) augite-hornblende andesite pyroclasts, 7) quartz diorite porphyry, 8) outline of the borska reka mineral deposit, 9) bor conglomerates, 10) underground workings. 2simić, d. & mihajlović, b. (2006): elaborat o rezervama bakra i pratećih elemenata u ležištu borska reka [elaborate of reserves of copper and accompanied elements in borska reka deposit – in serbian].– ministry of mines and energy, serbia, found of geological documentation, 147 p. 150 vol. 69/1 it consists of chalcopyrite and pyrite, with rare molybdenite. anhydrite veins are commonly associated with this type of mineralization. locally-developed argillic alteration (dominated by kaolinite and/or montmorillonite) variably overprints both high-sulphidation and porphyry-style alteration. 3) transitional epithermal zone located between the high sulphidation and porphyry cu-au mineralization. it comprises covellite and enargite replacing the primary sulphide (chalcopyrite) in porphyry cu-au mineralization, and is associated with gypsum, anhydrite, calcite that is typical of the high sulphidation zone. based on preliminary observations, it is believed that the massive sulphide type of mineralization contains > 10 mt of ore with > 5% cu, which corresponds to the amount of ore and copper content exploited from bor deposits in the period 19021941 (čoka dulkan ore body 12 million tonnes of ore with 5.6% cu and 2.6 g/t au). preliminarily estimation of mineral resources in the massive-sulphide type mineralization amounts to approximately 45 million tonnes of ore with 3% cu and about 1.4 mt of copper metal. total mineral resources of copper could amount to between 500 and 1000 million tonnes. in this way, the newly-found copper and gold deposits čukaru peki, can be compared with the bor cu-au complex, ranking highly on the world’s deposit scale (reservoir minerals, 2014)3. volcanogenic polymetallic hydrothermal deposits of massive sulphides (cu-pb-zn) with high gold content is formed in upper cretaceous volcanites under conditions of highly sulphidizing systems (čoka marin deposit, živković, 1987). it is located in a volcano-sedimentary series between pelites with disseminated haematite and with the intercalation of tuffs and volcanic breccia in the hanging wall and hydrothermally altered andesites and andesite breccia in the footwall. ore bodies are in a form of elongated lenses which by its morphology are reminiscent of a stratiform type of deposit (fig. 11). the mineral association consists of pyrite, gel-pyrite, limited pyrrhotite, marcasite, enargite, luzonite, chalcopyrite, scarcely bornite, sphalerite, galena and pb-zn sulphosalts. gold is a very significant component of this ore mineralization, in the form of native gold or bound to sulphides. stannine, cassiterite and bravoite occur locally as a component part of the mineral paragenesis. a significant part of the mineral paragenesis originates from colloid solutions. gangue minerals are quartz, a limited quantity of barite, anhydrites, siderite, calcite and in exceptional cases fluorite. figure 8. cross-section through the majdanpek porphyry copper deposit (vujić et al., 2005). figure 9. cross-section through the bor copper-gold deposit and the čukaru peki deposit. 3reservoir minerals (2014): ni 43-101 technical report on a mineral resource estimate on the čukaru peki deposit, brestovac-metovnica exploration permit, serbia. retrieved from: http://www.reservoirminerals.com 151 jelenković et al.: the mineral resources of the bor metallogenic zone: a review country rock alterations are characterized by advanced argillite alterations (alunite, diaspore, sericite) and widespread silicification, pyritization and chloritization (živković, 1987). the ore mineralization contains 1-3% cu, 5-8% zn and up to 1% pb, while the au content is 5-10 g/t, locally over 20 g/t. copper skarn (contact replacement) ore-bearing zones include: 1) veliki krš zone and 2) beljevina zone. veliki krš, 750 m long ore-bearing zone, includes several small ore bodies (1-8 m in width). dominant minerals are pyrrhotite, chalcopyrite, bornite, sphalerite, molybdenite, pyrite, chalcocite, galena etc. beljavina is a zone 600 m long and 20-12 m in width and includes the beljanica deposit and several small mineral occurrences with the same mineral composition. the copper content varies from 0.44-0.94%. mechanically redeposited cu-au mineral resources. the novo okno ore deposit belongs to this type of mineralization; its ore reserves are 2 250 000 tons, average copper concentration 4.85% (janković et al., 2003). ore-clasts are formed by the explosive destruction of the primary massive copper sulphide deposits of the bor deposits, their ejection onto the surface and gravity slides down the volcanic land-slopes into a marine basin (antonijević, 2011). there are also some occurrences of ore-clasts near metovnica and north of bor town (čoka bare, ujova). 5.2. gold mineral resources gold mineral resources of the bor metallogenic zone are widely distributed. gold is present as an accompanying component in porphyry copper deposits and as an epithermal, high-sulphidization type, low sulphidization type and sediment-hosted gold mineralization type (koželj, 2002). high-sulphidation epithermal gold mineralization comprises deposits and occurrences in which gold is a leading constituent of the mineralization (čoka kupijatra and tilva njagra) as well as deposits in which gold is an accompanying, but very significant mineralization component (hydrothermal volcanic copper deposits – ore bodies of massive sulphides in the upper part of bor deposit, then čoka kuruga, lipa, as well as polymetallic deposits cu, pb, zn of the type čoka marin type). low sulphidization epithermal gold mineralization is known in the area of zlaće-crvena reka as an independent mineralization system, accompanying porphyry copper deposits which are localized in high-plutonic levels where numerous dykes occur (deposit veliki krivelj, cerova) and as the youngest mineralization stage in porphyry copper deposits (e.g., the majdanpek deposit). sediment-hosted gold mineralization is located along the western margin of the tmc (the potaj čuka – tisnica ore district, i.e. bigar hill, kraku pešter and korkan deposits). the district, as currently defined, is at least 25 km in length and up to 10 km wide. gold mineralization is associated with a complex geological and structural sequence of limestone/ marble, calc-silicate hornfels, biotite-magnetite hornfels, monzonite, diorite dykes, andesitic volcanic and volcaniclastic rocks, schists and tuffaceous sedimentary rocks. the mine ralized area is extensively faulted and intruded by numerous diorite and monzonite complexes with associated thermally metamorphosed aureoles, indicating the potential for sufficient permeability and the rheologic contrast for fluid figure 10. general genetic model of the bor system. figure 11. cross-section through the čoka marin pb-zn-cu-au-ag deposit (živković, 1987). 4avala resources (2014). timok gold project ni 43-101 technical report and mineral resource estimates. retrieved from: http://www.avalaresources.com. 152 vol. 69/1 movement and hydrothermal deposition (avala resources, 2014)4. the gold mineralization appears to be associated with fine-grained pyrite (sulphidation reaction) and with alteration zones including kaolinitization, decarbonatization of calcareous sedimentary rock and occasionally silicification. the gold mineralization is mostly hosted within a favourable sedimentary package which is underlain by jurassic and lower cretaceous limestones (kls limestone) and consists predominantly of calcareous sandstones and conglomerates which include an interbedded fine-grained sandstone and clay-rich siltstone unit. the upper portion of the target stratigraphy consists of ‘red’ sandstones and volcanic-lithic clastics (s2 red sandstones) which are in turn overlain by calcareous marls, andesitic volcanics and derivative clastic rocks, which represent the youngest portion of the stratigraphy. 5.3. lead-zinc mineral resources according to mineral associations and conditions of formation, lead-zinc mineral resources of the bor metallogenic zone can be classified as follows: a) skarn / carbonate replacement type (pb, zn, ag sulphide) mineral resources, b) mineral resources of vein pb-zn sulphide type and c) mineral resources of massive pb-zn sulphides, of volcanic origin. all of them are mainly of small dimensions, but locally may be of economic interest. skarn pb-zn and carbonate replacement polymetallic (au, ag, pb, zn, as) deposits rarely occur. the valja saka skarn deposit formed in a small limestone block close to the valja strž granitoide complex. the mineral paragenesis includes galena and sphalerite as the dominant minerals. estimated ore reserves are 500 000 tons with 2.1% pb, 1.85% zn and 0.21% cu. korkan east occurrences are located in the deeper part of the korkan au deposit, in the contact zone between the limestones and andesites of the tmc. the gold and base metal mineralized rocks at korkan east show characteristic features of carbonate replacement deposits. it comprises a polymetallic style of mineralization, containing elevated levels of gold, silver, lead, zinc, and arsenic. hydrothermal vein deposits of lead-zinc sulphides are relatively frequent in the bor metallogenic zone senso stricto, but are not economically viable. thickness of ore veins is most frequently between 0.2-1 m. along the strike they quickly narrow. ore viens are localized usually in andesites, as independent ore bodies, or they are formed in certain copper deposits usually in the last stage of mineralization. the latter is the case with the porphyry copper deposits of majdanpek and borski potok, where copper-bearing mineralization is cross-cut by hydrothermal veins of lead-zinc sulphides. ore deposits of massive lead-zinc sulphides are rare in the bor metallogenic zone. it is located on the rim of porphyry cu-au mineralization in north district of majdanpek deposit (type: tenka, fig. 13). tenka deposit is formed at the contact of jurassic limestones and upper cretaceous subvolcanic intrusions of andesites. these are typical metasomatic bodies that occurred along the steep breaking zone so that ore bodies are in the form of steep columns and morphologically complex ore veins, with additional local lenses and isometric ore bodies. dimensions of the ore bodies are variable; thicknesses vary from several to 20 m, locally up to 30 m; with a length of up to 450 m. the vertical interval of mineralization does not exceed 150 m. figure 12. cross-section through the bigar hill gold deposit (van der toorn et al., 2013). figure 13: cross-section through the tenka cu-pb-zn deposit (vujić et al., 2005). 153 jelenković et al.: the mineral resources of the bor metallogenic zone: a review the mineral paragenesis comprises pyrite as the most dominant mineral, then sphalerite, galena, chalcopyrite, scarcely enargite and luzonite, pyrrhotite, tetrahedrite, rarely bornite. gold occurs as its native form but also bound to sulphides. copper, lead and zinc are irregularly distributed in the ore bodies. the mineral potential of the tenka deposit has been estimated as 4 million tons of ore with 0.5 % cu, 1.1 % pb, 4.4% zn, 1.3 g/t au and 28 g/t ag. besides the tenka deposit, polymetallic mineralization (cu, zn, pb with gold), closely related to pyrite ore bodies, is also known in the dolovi locality in the southern district of the majdanpek deposit. table 2. mineral resources and ore reserves of copper, gold and silver in the selected mineral deposits of the bor metallogenic zone senso stricto (explanation: m-measured mineral resources, i-indicated mineral resources, ifinferred mineral resources /perc, 2008/5. balance a+b+c1 balance (economic) reserves /according to the book of regulations on classification and categorization of reserves of solid mineral raw materials and keeping a file on them, 1979/6. ore reserves – proven and probable reserves, according to perc, 2008. data source: (1) ministry of mines and energy, serbia. (2) found of geological documentation rtb, (3) reservoir minerals, (4) avala resources). 5pan-european code for reporting of exploration results, mineral resources and reserves (the perc reporting code), 2008. 6pravilnik o klasifikaciji i kategorizaciji rezervi čvrstih mineralnih sirovina i vođenju evidenciije o njima, službeni list sfr jugoslavije broj 53/1979 [the book of regulations on classification and categorization of reserves of solid mineral raw materials and keeping a file on them].– unpubl. report, službeni list sfr jugoslavije broj 53/1979. beograd. deposit mineral resources (cut-off 0.2% cu) ore, t cu, % au, g/t ag, g/t cu, t au, t ag, t 1majdanpek nr m+i 228 085 000 0.3 0.256 1.94 684 255 58.39 442.48 balance, a+b+c1 228 085 000 0.3 0.256 1.94 684 255 58.39 442.48 ore reserves 46 200 132 0.362 0.37 1.39 167 244 17.094 64.22 1majdanpek sr m+i 409 171 000 0.328 0.06 0.54 1 342 080 24.55 221 balance, a+b+c1 246 082 000 0.36 0.19 1.44 885 895 46.76 354.36 ore reserves 98 257 000 0.398 0.23 1.49 391 062 22.6 146.4 1čoka marin m+i 270 800 2.16 5.35 37 5 849 1.45 10.02 balance, a+b+c1 220 700 2.08 5.92 40.53 4 600 1.31 8.94 ore reserves 110 600 3.64 15.87 152.49 4 025 1.76 16.87 1valja strž i+if (0,3% cu) 108 200 000 0.26 0.19 0.79 281 320 20.56 85.48 balance, a+b+c1 47 299 000 0.31 0.27 0.9 146 627 12.77 42.57 ore reserves 36 977 000 0.281 0.227 0.865 103 905 8.394 31.985 1kraku bugaresku – cementacija m+i 70 092 715 0.3 0.09 1.21 210 278 6.31 84.81 balance, a+b+c1 45 800 000 0.31 0.09 1.2 141 980 4.12 54.96 ore reserves 24 991 000 0.34 0.09 1.2 84 969 2.25 29.99 1cerovo m+i 319 377 890 0.31 0.14 0.86 990 071 44.71 274.66 balance, a+b+c1 150 138 000 0.33 0.14 0.94 495 455 21.02 141.13 ore reserves 88 750 000 0.36 0.17 1.06 319 500 15.09 94.08 1veliki krivelj m+i 506 460 237 0.367 0.07 0.4 1 858 709 35.45 202.58 balance, a+b+c1 465 150 000 0.34 0.07 0.4 1 581 510 32.56 186.06 ore reserves 152 739 000 0.337 0.07 0.39 514 730 10.69 59.57 1bor – mine m+i 18 310 000 0.8 0.2 1.5 146 480 3.66 27.47 balance, a+b+c1 16 338 000 0.86 0.21 1.6 140 507 3.43 26.14 ore reserves 7 263 000 1.02 0.24 1.7 74 083 1.74 12.35 1borska reka if 450 922 103 0.49 0.109 1.72 2 209 518 49.15 776 m+i 556 911 000 0.57 0.206 1.67 3 174 393 114.72 930.041 balance, a+b+c1 319 969 000 0.5 0.2 1.62 1 599 845 63.99 518.35 ore reserves 130 463 000 0.56 0.24 1.66 730 593 31.31 216.57 2mali krivelj if+i 353 329 000 0.29 1 024 654 3čukaru peki if 65 300 000 2.6 1.5 1 697 800 97.95 4potoj čuka – tisnica if 4 300 000 1 4.3 i 67 420 000 1.14 76.86 4korkan east if 1 370 000 3.4 4.66 resources m+i 2 108 678 642 8 571 369 386.66 2 211.33 resources if 520 522 103 3 920 764 172.5 794.27 balance, a+b+c1 1 519 081 700 5 680 674 244.35 1 774.99 ore reserves 585 750 732 2 390 111 110.93 672.04 154 vol. 69/1 5.4. iron mineral resources iron mineral resources belong to groups of: a) skarn mineralization and b) limonite ore bodies in relation to porphyry copper deposits. skarn iron (magnetite) mineralization is located in two main zones: 1) žagubica zone and 2) majdanpek zone. in the žagubica ore-bearing zone (i.e. frasen-biger potokumka zone) where small occurrences potaj čuka and umka are located, the ca-skarn mineralized zone covers 5 km2 (15 km x 0.5-3 km). ore bodies are in the form of nests and lenses composed of compact magnetite ores. magnetite ore from potoj čuka contains 59.2% fe, 4.1% sio2, 0.05% p and 0.06% s. magnetite ore from the umka zone (cover 2 km2), contains 64.6% fe, 4.5% sio2, 0.06% p and 0.05% s. the majdanpek ore-bearing zone contains several small compact magnetite ore bodies in the form of nests and lenses with 58.7% fe, 4.0% sio2, 0.07% p and 0.05% s. limonite ore bodies are located in the majdanpek ore deposit. they were formed as a result of the oxidation of pyrite ore bodies. the biggest one is the blašard ore body. indicated mineral resources of limonite are 2 mt with 45% fe, 0.4% cu, 0.1-1.3% zn and 0.1-0.5% pb. 6. mineral resources and mineral reserves mine production from copper-gold mineral deposits of the tmc from 1902 to the present day was 652 mt of ore with 4.93 mt of cu and 280 tons of gold. today, officially confirmed, measured and indicated copper and gold resources in the identified ore bodies are 8.57 mt of cu and 310 tons of gold. inferred copper resources are 3.92 mt of cu and 156 t of gold (table 2). in this way, the bor metallogenic zone according to copper and gold resources represents one of the most important metallogenic units in serbia. prognostic mineral resources of the bor metallogenic zone are estimated at over 20 millions of tons of copper and 1,000 tons of gold in currently identified ore bodies. 7. conclusion during more than 100 years of exploration it was established that cooper and gold mineralization are not uniformly distributed in the tmc. the most significant deposits are located in its northern part, between majdanpek and bučje. in the northern extension of the tmc, where the trough structure continues into a fault to the danube and romania, and in the southern extension in the nevlje-borov dol area (serbianbulgarian border), copper-gold mineralization was identified but not systematically explored. the probability for new copper and gold deposit discoveries in these areas is considerably lower when compared to the bor metallogenic zone senso stricto. judging by the vertical interval of copper-gold mineralization observed in the of existing mineral deposits in the bor metallogenic zone the possibilities for discovering new copper and gold mineral resources, are at depth (fig. 14). this supports the earlier mentioned discovery of copper-gold mine ralization in the brestovac ore field and in the deeper part of the borska reka porphyry copper deposit in the bor system. it is important to say that in the past the largest number of copper and gold deposits was investigated in detail only to the level of -100 m. on the other hand, there is recently defined, previously unrecognized sediment-hosted type of gold mineralizations located along the western margin of the timok magmatic complex. they share many common geological characteristics with the carlin-type gold deposits in nevada, usa, including the characteristics of the sedimentary host and the metal association (au, as, hg, tl, sb, and base metals). the fine-grained nature of the gold, the high gold to silver ratio and alteration types, including argillization, decarbonization and locally additions of quartz, speaks in favour of the necessity for new investments in geological exploration of this type of mineralization. the presently identified resources of gold in this type of mineralization represent more than 30% of the previously known quantities of gold in porphyry and other cu-au deposits in the timok magmatic complex. according to the presented results of geological exploration, an additional significant gold mineralization is associated with carbonate replacement deposits composed of arsenopyrite, sphalerite and galena (korkan east). the link between the replacement deposit at korkan east and the nearby lower temperature sediment-hosted gold is unclear. the authors of this paper their knowledge, ideas and research methods were given of the best known geology of mine­ral­ deposits­ in­ this­ area,­ acad.­ ivan­ jurković­ and­ professor­slobodan­janković.­continue­their­work.­thank­ them. figure 14. vertical interval of copper-mineralization in selected copper-gold deposits. 155 jelenković et al.: the mineral resources of the bor metallogenic zone: a review abbreviations abcd; alpine-balkan-carpathian-dinaride geodynamic province. aj; ježevica andesite. ao; osnić basaltic andesite. at; timok andesite. bmmb; banatitic magmatic and metallogenic belt. em; metovnica epiclastite. lb; boljevac latite. mt; million tonnes. pdc; porphyry copper deposits. pge; platinum group elements. pvs; valja strž plutonite. temb, tethyan eurasian metallogenic belt. tmc; timok magmatic complex. references antonijević, i. (2011): the novo okno copper deposit of olistostrome origin (bor, eastern serbia).– annales géologiques de la peninsule balkanique, 72, 101–109. doi: 10.2298/gabp1172101a banješević, m. (2006): gornjokredni magmatizam timočkog magmatskog kompleksa [upper cretaceous magmatism of the timok magmatic complex – in serbian, with an english abstract].– phd thesis, faculty of mining and geology, belgrade university, belgrade, 184 p. banješević, m. (2010): upper cretaceous magmatic suites of the timok magmatic complex. annales géologiques de la peninsule balkanique, 71, 13–22. doi: 10.2298/gabp1071013b banješević, m. (2015): geološka karta republike srbije (kartografska građa) [geological map of the republic serbia (cartographic composition, zaječar 1 – 1:50000)], zaječar 1 – 1:50000.– geološki zavod srbije, beograd. banješević, m., cvetković, v., von quadt, a., peytcheva, i. & cocić, s. (2006): geodynamic reconstructions based on the magmatism in the timok magmatic complex (east serbia) – part of the carpathian-balkan belt.– 18th congress of carpathian-balkan geological association, belgrade, 27–29. banješević, m. & large, d. (2014): geology and mineralization of the new copper and gold discovery south of bor timok magmatic complex.– proceedings of the xvi serbian geological congress, serbian geological society, donji milanovac, 2014, 739–741. berza, t., constantinescu, e. & vlad, s.n. (1998): upper cretaceous magmatic series and associated mineralization in the carpathian-balkan orogen.– resource geology, tokyo, 48/4, 281–306. borojević šoštarić, s., palinkaš, l., neubauer, f., cvetković, v., bernroider, m. & genser, j. (2014): the origin and age of the metamorphic sole from the rogozna mts., western vardar belt: new evidence for the one-ocean model for the balkan ophiolites.– lithos, 192– 195 (2014), 39–55. doi:10.1016/j.lithos.2014.01.011 clark, h.a. & ullrich, d.t. (2004): 40ar/39ar age data for andesitic magmatism and hydrothermal activity in the timok massif, eastern serbia: implications for metallogenetic relationships in the bor copper-gold subprovince.– mineralium deposita, 39, 256–262. doi: 10.1007/s00126-003-0370-3 đorđević, m. & banješević, m. (1997). geologija južnog depa timočkog magmatskog kompleksa, tumač geološke karte 1:50000 [geology of the southern part of the timok magmatic complex, booklet and geological map 1:50000 – in serbian].– federal ministry of economy fr yugoslavia, belgrade, 171 p. đorđević, m. (2005): volcanogenic turonian and epiclastics of the senonian in the timok magmatic complex between bor and the tupižnica mountain, eastern serbia.– annales géologiques de la peninsule balkanique (for 2004 – 2005), 66, 63–71. doi: 10.2298/gabp0566063d drovenik, m. (1959): complement to understanding the timok eruptive massive rocks.– rasprave in poročila, geologija, 5, 11–21 (in slovenian). heinrich, c.a. & neubauer, f. (2002): cu-au-pb-zn-ag metallogeny of the alpine-balkan-carpathian-dinaride geodynamic province.– mineralium deposita, 37, 533–540. doi: 10.1007/s00126-002-0271-x janković, s. (1976): the copper deposits and geotectonic setting of the tethyan eurasian metallogenic belt. 25th intern. geol. congr. sydney.– mineral deposits, 12, 37–47, (1977). doi: 10.1007/bf00204503 janković, s. (1980): metallogenic features of copper deposits in the volcanointrusive complexes of the bor district, yugoslavia.– monograph european copper deposits. janković, s. & sillitoe, r.h. (eds.): sga – spec. publ. no 1, copper mining, smelting and refining corporation, bor and department for economic geology, faculty of mining and geology, belgrade university, belgrade, 42–49. janković, s. (1990): rudna ležišta srbije: regionalni metalogenetski položaj, sredine stvaranja, i tipovi ležišta [the ore deposits of serbia: regional metallogenic settings, environments of deposition, and types – in serbian, with an english abstract].– faculty of mining and geology, belgrade, 760 p. janković, s. (1997): the carpatho-balkanides and adjacent area: a sector of the tethyan eurasian metallogenic belt.– mineralium deposita, vol. 32, no. 5, 426–433. doi: 10.1007/s001260050110 janković, s., jelenković, r. & vujić, s. (2003): mineralni resursi i prognoza potencijalnosti metaličnih i nemetaličnih mineralnih sirovina srbije i crne gore na kraju 20. veka [mineral resources and prognosis of potential of metallic and non-metallic mineral raw materials in serbia and montenegro at the end of the 20th century – in serbian, with an english abstract].– engineering academy of serbia and montenegro. belgrade, 875 p. karamata, s. & djordjević, p. (1980): origin of the upper cretaceous and tertiary magmas in the eastern part of yugoslavia.– bulletin academie des serbe des sciences et des arts, classe des sciences mathematiques et sciences naturalles, v. 32, 1–p. karamata, s., knežević-djordjević, v. & milovanović, d. (2002): a review of the evolution of upper cretaceous–paleogene magmatism in the timok magmatic complex and the associated mineralization.– in: koželj, d. & jelenković, r. (eds.): geology and metallogeny of the copper and gold deposits in the bor metallogenic zone, qwerty, bor, 15–28. kolb, m., von quadt, a., peytcheva, i., heinrich, c.a., fowler, s.j. & cvetković, v. (2013): adakite-like and normal arc magmas: distinct fractionation paths in the east serbian segment of the balkan-carpathian. arc journal of petrology, 54/3, 421–451. doi: 10.1093/petrology/egs072 koželj, d. (2002): epitermalna mineralizacija zlata borske metalogenetske zone: morfogenetski tipovi, strukturno-teksturni varijeteti i potencijalnost [epithermal gold mineralization in the bor metallogenic zone: morphogenetic types, structural-texture varieties and potentiality – in serbian, with and english abstract].– grafomed, bor, 216 p. kräutner, h.g. & krstić, b. (2002): alpine and pre-alpine structural units within the southern carpathians and the eastern balkanides.– proceedings of xvii. congress of carpathianbalkan geological association bratislava, september 1 – 4, 2002, geologica carpathica, 53, special issue, 7 p. ljubović-obradović, d., carevac, i., mirković, m. & protić, n. (2011): upper cretaceous volcanoclastic-sedimentary formations in the timok eruptive area (eastern serbia): new biostratigraphic data from planktonic foraminifera.– geologica carphatica, 62/5, 435–446. doi: 10.2478/ v10096-011-0031-x majer, v. (1953): prilog razumevanju monconitskih stena u istočnoj srbiji [complement to the understanding of monzonitic type rocks in eastern serbia – in serbian, with an english abstract].– vesnik geozavoda, 10, 135–147. milovanović, d., karamata, s. & banješević, m. (2005): petrology of the alkali basalts of zlot, timok magmatic complex (eastern serbia).– tectonophysics, 410/1–4, 501–509. doi:10.1016/j.tecto.2005.06.012 palinkaš, l., borojević šoštarić, s. & strmić palinkaš, s. (2008): metallogeny of the northwestern and central dinarides and southern tisia.– ore geology reviews, 34/3, 501–520. doi: 10.1016/j.oregeorev.2008.05.006 schmid, s.m., bernoulli, d., fugenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine–carpathian–dinaridic orogenic system: correlation and evolution of tectonic units.– swiss j geosci, 101, 139–183. doi: 10.1007/ s00015-008-1247-3 van der toorn, j., davidovic, d, hadjieva, n., strmbanovic, i., márton, i., knaak, m., tosdal, r., davis, b. & hasson, s. (2013): a new sedimentary rock-hosted gold belt in eastern serbia.– mineral deposit research for a high-tech world, 1–4, (2013), 691–694. von quadt, a., peytcheva, i., cvetković, v., banješević, m. & koželj, d. (2002): geochronology, geochemistry and isotope tracing of the cretaceous magmatism of east serbia as part of the apuseni-timoksrednogorie metallogenic belt. 17th congress of carpathian-balkan geological association.– geologica carpathica, special issue, 175–177. vujić, s., grujić, m., salatić, d., radivojević, s. & jelenković, r. (2005): rudnik bakra majdanpek: razvoj, stanje, budućnost [copper mine majdanpek: development, state, future – in serbian, with and english abstract].– planeta print, beograd, 171 p. zimmerman, a., holly, j., stein & judith l. hannah, koželj, d. bogdanov, k. & berza, t. (2008): tectonic configuration of the apuseni-banat-timok-srednogorie belt, balkans-south carpathians, constrained by high precision re-os molybdenite ages.– mineralium deposita (2008), 43, 1–21. doi: 10.1007/s00126-007-0149-z živković, p. (1987): petrologija i alteracije ležišta čoka marin 1 [petrology and­alterations­of­čoka­marin­1­ore­deposit – in serbian].– msc thesis, faculty of mining and geology, belgrade, 46 p. 2022 | 75/2 | 269–287 | 4 figs. | 1 tab. | 2 appx. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction since 2011, one of the major concerns of the european commission has been a sustainable supply of the critical materials to maintain and develop the european industries (european commission, 2011). the european commission communication listed 27 critical raw materials in 2017 (european commission, 2017). the adria region hosts significant primary geological potential for six of these critical materials, namely antimony, barite, bauxite, borate, lithium and mg (magnesite). with the exception of borates and lithium, these primary commodities were exploited prior to the conflicts in the region during the 1990s when the adria region generated 11% of the world’s magnesite, 5% of the bauxite, 5% of the antimony, and 3% of world’s barite production (reichl & schatz, 2021). due to a complex geopolitical situation, geological data from the adria region are outdated, segmented, and limited, and largely not included in the pan-european mineral deposits databases: minerals4eu and promine. the eu commission review of the list of critical raw materials (european commission, 2017) has not taken into consideration the crm potential of the adria region, even though non-eu adria countries, including bosnia and herzegovina, are following the european path of slovenia and croatia, and initiating access negotiations with significant funding the geological potential of antimony, bauxite, fluorite, and magnesite of the central dinarides (bosnia and herzegovina): an exploration and exploitation perspective sibila borojević šoštarić1, anže markelj2, eldar jašarević3 and angelika haindl4 1 faculty of mining, geology and petroleum engineering, department of mineralogy, petrology and mineral resources, pierottijeva 6, hr-10000 zagreb, croatia; (sibila.borojevic-sostaric@rgn.unizg.hr) 2 geology survey of slovenia, department for regional geology, dimičeva ulica 14, 1000 ljubljana, slovenia; (anze.markelj@geo-zs.si) 3 mining institute tuzla, scientific research center for geology, geotechnics and civil engineering, rudarska 72, 75000 tuzla, bosnia & herzegovina; (eldar.jasarevic@rudarskiinstituttuzla.ba) 4 chair of mining engineering and mineral economics, department mineral resources engineering, montanuniversität leoben, franz-josef-straße 18, 8700 leoben, austria; (angelika.haindl@unileoben.ac.at) doi: 10.4154/gc.2022.16 abstract this paper presents the critical raw materials (crm) potential of antimony, bauxite, fluorite, and magnesite deposits in bosnia and herzegovina, discusses their metallogeny and joint geological features, and explains the methodology of the investrm application and evaluation criteria for the selected commodities in the following steps: (1) preparation of the geological data templates, (2) evaluation and verification of the geological data, (3) ranking of deposits according to the geological data relating to quality and quantity, and (4) identification of the 10+ perspective deposits. existing geological datasets show the existence of significant potential in primary crm such as bauxite (56 mt), magnesite (4 mt), and antimony (0.2 mt) in bosnia and herzegovina (bih). the geological settings of bih provide favourable metallogenetic conditions primarily for bauxite and magnesite deposits but also for antimony within polymetallic deposits, while fluorspar is rather rare. our methodology described herein led to the selection of the following fourteen deposits for further geological prospection and investment: the polymetallic antimony deposits čemernica and podhrusanj, antimony fields srebrenica and rupice; magnesite fields kladanj, banja luka, teslić and novi šeher and bauxite regions vlasenica-srebrenica, grmeč mountain deposits in una-sana region and south bosnia regions from posušje to trebinje. a basic economic calculation based on the world producer ranking and a self-sustainability and economic contribution assessment shows that further investments in geological exploration and mining of antimony, magnesite, and bauxite crm could place bih on the list of important producers of these commodities in europe. through the mechanism of pre-structural aid, and will join the european family in the future. currently, china is the leading supplier of several important raw materials, including antimony (87%), magnesium (87%), and rare earth elements commonly present in some bauxites (95%) (european commission 2017). the dependence on china increases the risk of supply shortages and supply vulnerability along the value chain. bosnia and herzegovina still have significant potential in primary critical raw materials (antimony, bauxite, magnesite), while the current production is negligible even though operating quarries, open pits, and mines represent important and strategic assets. many large deposits, such as the vareš, srebrenica area, west herzegovina, and the jajce bauxite deposits, are known to european investors from past exploitation. a long mining tradition, existing geological potential, and the strategic position of the country close to the production centers of the major european industries still hasn’t resulted in a significant rate of investment in the mining of the critical raw materials in bosnia and herzegovina. some of the main issues preventing investments are the complexity of the internal organizational structure covering exploitation and exploration licensing in bosnia and herzegovina and the fragmentation, quality, and quantity of existing geological datasets. article history: manuscript received november 18, 2021 revised manuscript accepted february 23, 2022 available online june 23, 2022 keywords: crm exploration, mining potential, bosnia and herzegovina, central dinarides, antimony, bauxite, fluorite, magnesite g eo lo gi a c ro at ic a geologia croatica 75/2270 in response to the aforementioned shortcomings, the aim of this paper is to: 1. present the metallogeny and joint geological features of the selected 120+ antimony, bauxite, fluorite, and magnesite deposits in bosnia and herzegovina, 2. present the developed investrm application and evaluation criteria for the deposits in bosnia and herzegovina (https://investrm.eu/app-tb/), 3. implement evaluation criteria for the 120+ antimony, bauxite, fluorite, and magnesite deposits, and select the 10 highest-ranking deposits, and 4. investigate and discuss the exploration and mining potential of the selected deposits. 2. geological setting the dinarides are a folded, thrusted, and imbricated belt located between the southern alps in the northwest and the hellenides in the south and southeast (pamić et al., 1998). the territory of bih encompasses part of the dinarides, consisting of several detachments of tectonostratigraphic and lithostratigraphic units of different origin and stratigraphic sequences related to the alpinecarpathian orogenic process of the palaeozoic to neogene age (pamić et al., 1998; schmid et al., 2008). the predominant structures are several thrusts with sw vergence, which, at a regional scale, resulted in knappes and local klippes thrust on top of one another in today’s position. the dinarides are divided into several tectonic units, which include external and internal sectors from the adriatic sea units towards the ne up to the adjoining tisia mega-tectonic unit (zonation follows those reviews by pamić et al. (1998) and dimitrijević (1982, 1997); fig. 1): 1) the adriatic carbonate platform hosting bauxite occurrences and deposits, 2) palaeozoic basement units with surrounding bosnian flysch, hosting antimony, fluorspar, and bauxite deposits, 3) dinaric ophiolitic zone hosting magnesite deposits, and 4) sava-vardar zone hosting antimony deposits. the adriatic carbonate platform and its correlatives, together with the east bosnian-durmitor zone, constitute the external dinarides, while the dinaric ophiolite zone and the sava – vardar zone represents units of the internal dinarides. the adriatic carbonate platform comprises an upper palaeozoic basement, overlain by upper permian to norian clastic sediments and platform carbonates with penecontemporaneous rift-related igneous rocks, the norian-lutethian carbonate platform, and eocene overstep flysch sequences. the internal and external units of the dinarides both contain exposed palaeozoic basement units that have undergone various degrees of metamorphism (mainly up to greenschist, in some cases up to epidote-amphibolite facies conditions). the palaeozoic basement units are composed of ordovician to carboniferous (permian) metasediments (dominantly carboniferous flysch and permian molasse-type deposits) and metavolcanics mainly overlain by a triassic carbonate-clastic cover. the degree of metamorphism increases from the northwest towards the southeast, whereas the age of metamorphism ranges from variscan to alpine. the bosnian flysch is a 4000-5000 m thick passive continental margin carbonate-clastic tectonostratigraphic unit of jurassic to late cretaceous age. the dinaric ophiolite zone consists of mesozoic radiolarite sequences with basalt, greywacke, and shale and an ophiolite mélange, ultramafic thrust sheets, and late jurassic–early cretaceous and late cretaceous overstep sequences. the sava-vardar zone contains late cretaceous to palaeogene flysch sequences with volcanics, tectonized ophiolite mélange, regionally metamorphosed sequences originating from the surrounding late cretaceous–palaeogene rocks and synkinematic granitoids. the geodynamic evolution of the dinarides began with the early permian rifting of the palaeozoic basement rocks (borojević šoštarić et al., 2009; borojević šoštarić et al., 2012), followed by the opening of the tethyan ocean in the late triassic and the late jurassic–early cretaceous subduction and emplacement of the dinaric ophiolites (pamić et al., 1998). parts of the sava-vardar zone remained open until the early palaeogene (schmid et al., 2008). 3. geology and metallogeny of the crm deposits 3.1. antimony (a) palaeozoic, continental rift-related polymetallic hydrothermal deposits a. the quartz-sb-polymetallic (zn, hg, as, ag) hydrothermal deposits of the mid-bosnian schists mts. form a mineralizing zone of 3×0,3 km around fojnička banja, gradina and čemernica with numerous veins and tabularore bodies with a maximum thickness of 1,2 metres. the largest deposit in this ore field is čemernica, hosted within carboniferous-permian quartz-muscovite schists, sandstones, and carbonates. čemernica is a hydrothermal vein-type to tabular type of deposit containing, stibnite, stibarsene, cinabarite, sphalerite, tetrahedrite, boulan gerite, arsenopyrite, pyrite, and marcasite within a quartz matrix. the metal content is highly variable ( sb= 0,2-15%; zn = 2-10%; ag=50-200ppm; hg=0,01-0,1%; (jurković et al., 1999). b. the barite-pb-zn-sb vein-type hydrothermal mineralization with 0,1-0,4% of sb (totinovac-viduša) located near jajce, is hosted within a carboniferous-permian rift-related sequence in the vicinity of a palaeozoic quartz-porphyry. irregular veins, 0,1 – 0,5 m thick, and metasomatic bodies are composed of barite, galena, sphalerite, luzonite, stibnite, stibarsen and cinnabarite (ramović et al., 1979). c. the quartz-sb vein-type hydrothermal deposit podhrusanj is hosted within palaeozoic schists, sandstones, and carbonate rocks of the southeastern bosnia drina-ivanjica unit and is considered to be related to the granitic and syenite intrusion near čajniče (pamić, 1982; kubat, 1982; 1995). the mineralization is located at the contact zone between the impermeable schists and permeable limestones. average amounts of antimony in the mineralized carbonates vary from 1,1% to 3,4% of sb ( kubat 1982; 1995). d. the small-scale polymetallic (pb, zn, sb) vein and metasomatic replacement type deposit of podkozara belongs to a similar setting as the podhrusanj deposit (drina-ivanjica unit; (ramović et al., 1979)). (b) triassic advanced rift-related hydrothermal antimony deposits a. the barite-polymetallic (pb, zn, hg, sb) hydrothermal vein-type and metasomatic deposits at the rupice field (rupice, rid, veliki do, križ, veovača) are located within upper palaeozoic to middle triassic continental rift-related sandstone, limestone, and dolostone. the deposits are primarily mined for barite and pb-zn mineralization (pb+zn) = 2,3 – 6,5%, whereas the antimony-bearing minerals stibg eologia c roatica borojević šoštarić et al.: the geological potential of antimony, bauxite, fluorite, and magnesite of the central dinarides (bosnia and herzegovina) ... 271 nite, tetrahedrite, and boulangerite on average contain sb between 0,05 and 4,9%. the ore also contains ag of 65 g/t; au of 0,3 g/t; cu of 0,1%, and hg of 0,02% (operta & hyseni, 2016). based on the superposition and sedimentary evidence, these deposits are considered to be related to a middle – upper triassic advanced rift setting. (c) oligocene post-collisional deposits of the sava-vardar zone the polymetallic (pb, zn, sb, ag) vein and metasomatic type hydrothermal deposits of the srebrenice field (lisac, vitlovac, čumavić) are related to the oligocene dacite, andesite, and associated volcanoclastic formations that intruded into palaeozoic schists. the typical mineralogy of galena, sphalerite, siderite, chalcopyrite, stibnite, and pyrrhotite is accompanied by various sulfosalts containing pb, sb, cu, bi, ag (zarić et al., 2000). small-scale greisen-type sn-bearing mineralization developed at the magmatic-schists contact zone. 3.2. bauxite (a) external dinaride bauxites a. the south bosnia region (herzegovina; (burić & živaljević, 1979)) i. around 80 upper jurassic deposits (viduša) are embedded within the upper jurassic limestone and dolostone near viduša mt. in a 25 km long zone. the deposits are saddle-shape, of boehmite to gibbsite type, and contain 44-62% of al2o3, 2-10% of sio2, and 11-19% of fe2o3. ii. the most productive deposits are upper cretaceous – palaeogene in age, embedded between upper cretaceous to palaeogene carbonate rocks, with overlying liburinan beds, alevoline-numulite limestones, flysch sediments or promina beds (čitluk region: blatnica-lokvice, mamići-rasno-hamzići, ošljarifigure 1. a. geological scheme of studied area modified after pamić (1998), tomljenović (2008) and palinkaš (2008) with distribution of deposits and occurrences and corresponding keys-numbers linked to appendix 2, tables 1-4; b. regional geological setting according to pamić (1998) with emplacement (red bounded) of studied area. g eo lo gi a c ro at ic a geologia croatica 75/2272 krivodol, služanj, vitina-lipno; lištica region: crne lokve-kidačke njive, resnica-grabova draga, uzarici-knežpolje, varda planina; mostar region: žovnica, krstače-cerovi doci; posušje region: mratnjača-medine stanine, podzavelin-vinica, studena vrela, trebistovo-sobač, vinjani, volujakkadim, vučipolje, zagorje; stolac region: dabrica, gornji brštanik, hrgud). the boehmite-type deposits occur as lensoid layers/pockets within palaeokarst depressions with a maximum thickness of 15 metres. in the majority of the deposits, the amount of al2o3 is high (47-56%), with proportionally low sio2 (<10%). with an increase in sio2 of up to 18%, the amount of al2o3 decreases to 42%. some stratigraphically slightly higher horizons, overlying alevoline-numulite limestones (čitluk region: krehin gradac-blizanci, stolac region: bivolje brdo-domanovići, poplat) are smaller in size and of lower economic interest, containing 45-49% al2o3 and variable amounts of sio2 (0,1-14%). iii. the upper cretaceous – neogene deposits (lištica region: trn-sliškovića lokve) overlie upper cretaceous rudist limestones and are overlain by neogene clayey marls. these deposits are of bauxite clay type, containing high sio2 (14-33%) and low variable amounts of al2o3 (30-42%). b. the northwestern bosnia region (bosanska krajina; (burić & živaljević 1979)) i. the middle triassic deposits (bjelaj, veliki skočaj) occur within palaeokarst surfaces of the middle triassic limestones as irregular layer-like lenses and pockets covered with raibl beds and upper triassic dolostone. the deposit thickness varies between 2 and 12 metres. ooid to pisoid structures are common. the amount of al2o3 (boehmite, rarely gibbsite) varies between 29 and 69%, whereas fe2o3 varies between 2 and 20%, which affects the colour (white, pink, red bauxites). these deposits contain an avera ge of 3% tio2, whereas the amount of sio2 is variable and high (2 – 40%). ii. the upper jurassic deposits (krnjeuša-bravski vrhcrni vrh) occur as irregular lenses and nests within the lower jurassic limestones and are covered with upper jurassic to lower cretaceous limestones. bauxites are boehmite in origin, with high al2o3 (58-69%), low sio2 (3-8%), and an average of 3% tio2. iii. the upper cretaceous deposits (pritoka-tihotinatrovrh, suvaja-šolaja) are embedded within rudist limestone of upper cretaceous age. these deposits are layered to lensoidal, boehmite-type, with an ooid to pisoid structure, containing the highest quality al2o3-ore (55-75%), with very low sio2 (0-5%), and an average of 3% tio2. (b) internal dinarides cretaceous bauxites a. central bosnia region (jajce) the largest cretaceous karst bauxite deposits are located in the jajce region (bešpelj-crvene stijene, poljana, liskovica) and cover an area of nearly 350 km2. the formation of these deposits occurred during the 20 million-year terrestrial phase in the stratigraphic range from the upper albian to the santonian-campanian that resulted in tectonic-erosional discordance. the jajce bauxite deposits are of boehmite-type and differ in shape and geometry: lenticular, canyon-like, graben type, sinkhole type, and tetanized. the hanging wall of the bauxites is rudist-coral-bryozoan limestones or carbonate breccias of santonian-campanian age (dragičević et al., 2019). b. vlasenica-srebrenica region the cretaceous karst bauxite deposits of the vlasenica-srebrenica region (palež, podbraćan, šumarnica, štedra, crvene stijene, kosturi, gerovi, dragošnica, žedanjsko, pribojevići, kutuzero) are similar to the other internal dinaride deposits of the zlatibor and poćuta area in serbia and the grebnik area in kosovo. the bauxite deposits of the vlasenica-srebrenica region are located in a 30 × 4 km nwse trending zone in karst depressions in the middle triassic limestones and are covered by upper cretaceous limestones and/or a series of neogene conglomerates, sands, and clays (dangić, 2015). the bauxites are brown-red, hard boehmite-haematite in composition (+anatas, brucite) with oolitic-pisolitic structure and appear in beds, lenses, and pocket fillings, sometimes over 40 m thick. the deposits vary in size from a few tens of thousands to over 10 million tons of bauxite (braćan). secondary kaolinitization is common, as well as the formation of diaspore. 3.3. fluorite (a) early palaeozoic continental rift-related deposits i. as-polymetallic deposits with fluorite the arsenic-polymetallic (as, sb, hg, ba, f) hydrothermal deposit hrmza is located near kreševo in the midbosnian schist mts. the ore-bearing rocks are permocarboniferous phyllites, sandstones, and breccias. the mineralized zone is 0,5 to 3,0 m wide and consists of veins, impregnations, and nests. the main minerals are realgar and orpiment, followed by accessory fluorite, pyrite, bravoite, barite, muscovite, sphalerite, tourmaline, rutile, and antimonite. the fluorite has a dark purple color, and forms hexahedron crystals up to 1 cm in size. the tourmaline occurs regularly in veins alongside rutile and less commonly with fluorite. the quartz is mostly idiomorphically developed. the mineralogy points to a transition from a pneumatolytic to a hydrothermal phase, with fluorite precipitating late (jelić, 1979). ii. carbonate-hosted barite-fluorite deposits the mineralized zone containing the barite-fluorite deposits of mt. meovršje is about 22 km long and 2 to 4 km wide and represents part of the mid-bosnian schist mountains (jelić, 1979). the meovršje mt. encompasses a 300 m thick devonian carbonate complex, containing predominantly light-gray dolostone, followed by limestone and marble limestone. the underlying metamorphic complex contains chlorite and muscovite schists, phyllite, quartzite, and lydite. the carbonate complex hosts most of the barite deposits, which occur as impregnations, variously sized veins, or irregular bodies. the barite deposits appear as almost monomineralic bari te bodies, barite-quartz veins, barite-fluorite veins (meovršje), and barite-tetrahedrite veins. in the baritefluorite veins, the fluorite has an octahedral habit, and is colourless, violet, or transparent. the octahedral habit g eologia c roatica borojević šoštarić et al.: the geological potential of antimony, bauxite, fluorite, and magnesite of the central dinarides (bosnia and herzegovina) ... 273 indicates that the formation of fluorite took place under temperatures >200°c. the meovršje deposit contains predominantly barite (90 99 % wt. baso4 and about 6 % wt. srso4), ferroan dolomite, calcite, hg-sb tetrahedrite, quartz, pyrite, fluorite, and enargite. the accessory minerals are chalcopyrite, sphalerite, antimonite, sericite, tourmaline, and rutile (jelić, 1979). the barite-fluorite deposit žune in nw bosnia lies within the upper palaeozoic dolostone close to the contact with lower triassic schists and sandstones. the structure and texture of the vein show some evidence of hydraulic fracturing, an important indicator of boiling of hydrothermal fluid, as recognized in the fluid inclusion studies (palinkaš et al., 2016). the barite-fluorite vein is 3 to 9 m thick and vertically cuts the upper palaeozoic dolomites in an e–w direction. the contact zone consists of metasomatically recrystallized host dolomite with strings of tiny barite veins and impregnations. the central part of the vein consists of pure barite and some fluorite. the fluorite is mostly violet but can be blue to yellowish and has an octahedral habit. the accessories are calcite, quartz, sulfides and sulfosalts (tetrahedrite, cinnabarite, pyrite, realgar), and au (jeremić, 1958). iii. carbonate-hosted barite-siderite-fluorite deposits the vidrenjak-ljubija deposit in nw bosnia has a simi lar setting within the upper palaeozoic carbonate complex. however, the mineralization is discordant and irregular and contains siderite, limonite, sandy barite, and fluorite. (b) oligocene post-collisional occurrences rare occurrences of fluorite are found within pneumatolytic-hydrothermal alterations of s-type granitoids in the motajica mts. 3.4. magnesite deposits of the central dinaride ophiolitic zone the bosnian magnesite deposits and occurrences are genetically linked with serpentinized peridotite and dunite rocks of the central dinaric ophiolite zone of jurassic age (appendix 2, table 4). the quality and quantity of the magnesite increase from the northwestern kozara-pastirevo region towards the southeastern krivaja-konjuh region and the zlatibor region. the bosnian deposits are of the kraubath-type and appear as several hundredmetre long veins, veinlets, and impregnations of various thicknesses, containing micro-crystalline magnesite with variable primary carbonates (dolomite, calcite), and quartz (ilić & jelić, 1979; jurković et al., 2012). the vein-type ore varies between massive, banded, and brecciate and is up to 7-8 metres thick. about 25% of the reviewed magnesite deposits contain more than 40% mgo (appendix 2, table 4). the previous exploitation was mainly underground. brecciated fine-grained magnesite deposits are often cemented with coarse-grained neomagnesite or silica (quartz, opal, chalcedony), and contain remnants of the host-serpentinite, magnetite, or chromite. in the upper part of the deposits, silica veins and veinlets are very abundant, crosscutting and prevailing over primary magnesite. fe-hydroxide and mn-oxide occur as a weak coating over the magnesite. as a rule, the orientation of the majority of the micro-crystalline bosnian magnesite veins follows the major alpine tectonic structure oriented in a nw-se direction. the oldest veins are of early cretaceous age, coeval with the onset of lateritization in the dinarides. their vicinity close to the oligocene-miocene volcanic/plutonic rocks (moševac, and vlasenica-srebrenica fields), as well as the observed tectonic setting and textural sub-types (breccia-type) lead to the conclusion that their origin lies near the surface epithermal processes related to post-collisional magmatism in the dinarides (ilić & jelić, 1979). 4. methodology 4.1. investrm methodology the development of the methodology within the investrm project is divided into several complementary phases (fig. 2). through constant feedback from project partners and from public presentations at project info days, the methodology was continuously improved, resulting in the selection of high-potential deposits for exploration or reinstating abandoned or ongoing mining activities. 1st phase: geological data template geological templates gather available non-confidential geological data and tailor them to be aligned with: – transferability to existing comparable international raw materials databases (egdi-european geological data infrastructure: http://www.europe-geology.eu/) figure 2. invest rm methodology divided into complementing phases. g eo lo gi a c ro at ic a geologia croatica 75/2274 – investrm standardization for antimony, bauxite, fluorite, and magnesite occurrence types in the dinarides – terminology aligned with inspire – presenting essential data for evaluation of exploration and mining potential the geological template contains information on the geological characteristics of each of the 126 deposits (basic deposit information, deposit characteristics), supplemented with information on raw materials, reserve, processing, waste/environmental characteristics, additional info and references, thus enabling data harvesting and linking to the existing international raw materials deposits databases such as egdi (eurogeosurveys’ european geological data infrastructure; http://www.europe-geology.eu), and comparison with deposits worldwide. this is essential considering that the addressed critical raw materials in bosnia and herzegovina are currently only partly presented in worldwide databases. geological datasets have been extracted from available elaborates, technical documentation, reports, scientific papers, and geological maps. between the 1960s and the late 1980s, a mapping campaign supported by the government of the former yugoslavia responsible for the economic growth and planning resulted in geological maps at a scale of 1:100.000 for the entire territory of the former state. following the mapping campaign, čičić and co-authors (1979) provided a comprehensive overview of the targeted raw materials in a book covering ferrous, non-ferrous, and industrial commodities, as well as the energy generating materials in bosnia and herzegovina, which was used as a starting point for geological data extraction and supplemented with recent publications on the selected deposits. 2nd phase: evaluation and verification of geological data. for each of the 126 deposits/occurrences, the investment potential was estimated. the selection criteria were extracted from the world risk report (2017), whereas setting and adjusting the specific parameters for the selection criteria was done by the investrm consortia and consists of: (a) geological criteria (a level of current geological knowledge, i.e., data quality and quantity), and (b) non-geological criteria (social licensing, environmental management, project permits, skills availability). specific parameters for the geological criteria were set up separately for individual raw materials and are described in appendix 1. these include quality and quantity criteria summarizing reserves, exploration level, and favourable geological characteristics. reserves are aligned with the law governing geological exploration (official gazette of the fbih no. 9/10) and the rulebook on classification, categorization, and calculation of solid mineral raw material reserves and keeping records on them (official gazette of the fbih no. 36/12). reserves encompass a, b and c₁ categories (proven and measured), whereas resources are used for c₂, d₁ and d₂ categories (indicated and inferred) in line with the official gazette of the fbih no. 36/12. used literature sources for appendix 2 do not contain subdivided economical and non-economical reserves. 3rd phase: deposit ranking the principal parameters influencing ranking are the geological data quality (complete and relevant datasets from the geological data template) and data quantity (reserves, available past exploration data), as well as social licensing, environmental management, and project permits. parameters were weighed and assigned to ranks a, b or c, respectively, whereby a denoted excellent data with defined and up to date characteristics, b encompasses good-sufficient geological data, and c means no or minimal geological data with poorly estimated reserves and resources. the deposits considered to be the most potentially viable among the a rank deposits, namely those meeting all established criteria, were defined as a+ deposits with highly lucrative investment opportunities. the evaluated deposits were ranked and presented in detail in appendix 2 (tables 1-4). 4th phase: recognized 10+ perspective deposits deposits ranked a+ were described as highly lucrative investment opportunities, while a ranked deposits also present investment opportunities but do not meet all the predefined criteria. a number of a ranked deposits could be upgraded to a+ deposits by providing additional datasets as part of the geological prospection. 4.2. indicators to evaluate exploration and mining potential the exploration potential was estimated based on the geological setting of the wider area around an occurrence and the available data from previous exploration campaigns regarding the level of figure 3. data sources and processes used to calculate indicators of mining potential (copyright of original data used from world integrated trade solutions (wits) belong to the world trade organization (wto). conclusions and analyzes based on this data are the responsibility of the authors and do not necessarily represent the opinion of the wto. lom = life of mine) g eologia c roatica borojević šoštarić et al.: the geological potential of antimony, bauxite, fluorite, and magnesite of the central dinarides (bosnia and herzegovina) ... 275 uncertainty. the type of exploration method and targeted raw material (in polymetallic deposits) was also important in defining the exploration potential. reserves are a further important indicator (aligned with a valid classification and categorization method – appendix 2 (tables 1-4). to calculate the mining potential based on the geological data and economic information using the investrm tool, three indicators world producer ranking, self-sustainability, and economic contribution are introduced (fig. 3). the first indicator, ‘world producer ranking’, compares the theoretically mineable tons to the world production and helps to position bosnia-herzegovina on the global ranking list. the second indicator, ‘self-sustainability’, relates produced and imported tons, thus showing the ratio of materials derived from within bih and is thus an indicator of self-sustainability. the last indicator, ‘economic contribution’, evaluates the contribution of the country’s mines to bosnia-herzegovina’s economy in terms of taxed profits. a very simplified dynamic calculation method is applied to determine this value, as the input factors are based on assumptions. the calculation results based on current reserve tonnages are compared to numbers gained after upgrading c1 and c2 resources to a or b reserves. 5. results and discussion 5.1. exploration potential the exploration potential of a specific mineral commodity depends on the geological potential, the number and distribution of occurrences and deposits in an area. out of the total of 126 deposits of antimony, bauxite, fluorite, and magnesite in bosnia and herzegovina, 106 (or 84% of the investigated sites) are magnesite and bauxite deposits containing millions of tons of reserves and resources and showing high exploration potential (table 1). when comparing all the reserves and resources, bauxites have the greatest exploration potential, followed by magnesite, antimony, and fluorspar (table 1). the following results were obtained by applying the investrm methodology to the 126 investigated deposits: 1. three out of five fluorspar deposits were evaluated as a+ deposits. a field reconnaissance investigating the three deposits indicated that only the žune locality met each of the predefined criteria for the a+ rank. 2. four of thirteen antimony deposits were evaluated as a+ deposits. the čemernica and podhrusanj deposits are abandoned deposits, while the rupice and veovača deposits are currently under development with an exploration license. 3. six of fifty-seven magnesite deposits were evaluated as a+ deposits, including the magnesite field kladanj with the most prospective operating deposit miljevica and the poorly explored occurrences at zeničica and drinjača, all part of the kladanj magnesite region. furthermore, the abandoned deposit of ošve, which is part of the novi šeher magnesite field, was recognized as a highly prospective deposit. the magnesite regions of teslić, with several abandoned deposits, and snjegotina, with nine deposits currently not operating, were also highly ranked (a+). 4. fourteen out of fifty-one bauxite deposits were evaluated as a+ deposits. of these, we highlight three perspective regions, namely the krnjeuša-bravski vrh-crni vrh and pritoka-tihotina-trovrh fields, with exploration licenses, and vlasenica-srebrenica, with several operational deposits. in the areas listed above, the geological potential indicates highly lucrative investment opportunities with some additional exploration required to prove the reserves and resources estimated during previous campaigns. the magnesite and bauxite areas show a high prospectivity for exploration – with regions evaluated as a+ or a representing several deposits/regions controlled by the regional geological setting. in cases of positively evaluated magnesite, only the operational deposits were studied in detail. the areas surrounding existing deposits can hold additional reserves and resources, but this study included only operational or abandoned sites. abandoned deposits were categorized into the group of prospective sites when exploitation (or exploration) activities were undertaken there in the past, and the deposit was later abandoned for various reasons, such as feasibility, legislation, or environmental hazards resulting from inappropriate exploitation and processing techniques. larger areas present huge investment opportunities especially for long-term projects. magnesite and bauxite occurrences are generally ranked based on the amount of available data on reserves and resources and the quality of the data because these two crm represent the primary or sole rm mined in the chosen deposits. antimony and fluorite usually occur as secondary minerals in economically more interesting, predominantly pb-zn-fe, or barite deposits. therefore, reserves and resources are usually estimated, and the geological settings of studied areas were used as a key criterion. prospective fluorspar and antimony occurrences were studied in the investrm consortium to provide the possible geological potential for further exploration and feasibility studies. 5.1.1. bauxite bauxite deposits and occurrences are related to the adriatic carbonate platform and the internal dinaride cretaceous karst units. several promising bauxite-bearing areas have a high exploration potential (table 1): (1) the internal dinarides cretaceous karst deposit of the vlasenicasrebrenica region in eastern bosnia hosts 12.950.000 t (mitrović, 2011) of reserves, representing 25% of the total bauxite reserves in bih. active exploitation is operated by the company bauxite a.d. from milići. (2) grmeč mountain in the una-sana region has potential reserves (resources), with the bauxite-bearing potential estimated to be about 20.000.000 t (čičić, 1979), and has no active exploitation. (3) the external dinarides bauxite of the south bosnia region (posušje to trebinje), based on the number of registered bauxite deposits and occurrences, is an area with table 1. reserve, resources and exploration potential of flourspar, antimony, magnesite and bauxite in bih (data compiled after references used in verification and evaluation process: bodulić et al., (2018); burić et al., (1979); cvijić et. al., (1979); cvijić (2004); čičić (1979); dangić (1978, 1988, 2015); grubić (1975); grubić et al., (2016); jašarević et al., (2013); jejina et. al., (1977); jurić (1973); jurković (1961); kubat et. al. (1973); kubat (1995), mitrović (2011); operta et al., (2018), pavičić et al., (2018); ramović (1963) ramović et al. (1979); sunarić-pamić et al. (1988); todorović (2016). raw material no. of deposits/ occurrences total reserves (a+b+c1) total resources (c2+d1+d2) exploration potential fluorspar 5 low high antimony 13 100.000 t 115.000 t magnesite 57 537.784 t 3.414.700 t bauxite 51 35.067.305 t 20.852.000 t g eo lo gi a c ro at ic a geologia croatica 75/2276 potential for further bauxite exploration (burić & živaljević, 1979). active exploitation is operated by the company bauxite mines d.o.o. from posušje. 5.1.2. magnesite magnesite deposits and occurrences in bih are spatially and genetically related to the ophiolite zone of the dinarides. according to the degree of exploration, the most economically interesting magnesite regions are (as shown in table 1): (1) the magnesite field of kladanj which is a highly explored area with proven reserves of 193.484 t and a potential of 67.100 t (hodžić & djedović, 2014). active exploitation is operated by the company rudar d.o.o. from tuzla. (2) the banja luka magnesite field, with a low level of exploration and high-potential reserves exceeding 1.400.000 tons. it mainly belongs to the snjegotina magnesite field (jelovac = 420.000 t; pločni = 437.757 t; (ilić & jelić, 1979). the snjegotina field contains 25 magnesite occurrences investigated in detail, and more than 40 were partially investigated. previous research (ilić & jelić, 1979) yielded a promising geological and economic assessment. further research would likely result in additional discoveries. (3) the magnesite field of teslić, has three promising sites, namely blatnica (260.000 t), bukovački jarak (120.000 t) and milošev jarak (377.000 t) (ilić & jelić, 1979). magnesite bearing rocks include hornfels, amphibolite, and pyroxenite together with predominant serpentinized peridotite, whereby the magnesites have a high sio2 and cao contents. semi-industrial-scale tests were conducted to explore the possibility of magnesite enrichment by vari ous methods, with two-stage flotation giving optimal results (čičić, 1979). further industrial-scale testing is necessary to determine the techno-economic factors and classify proven reserves. (4) the magnesite field of novi šeher contains the ošve deposit with 215.000 t of resources (150.000 t c1 + 65.000 t c2). chemical analysis (čičić, 1979) has shown that the raw material is largely suitable for the production of metallurgical sinter, but not for the production of high-refractory bricks due to the elevated sio2 and cao contents. semi-industrial f lotation experiments (čičić, 1979) yielded promising results, similar to those for teslić, and should be complemented with industrial-scale testing. 5.1.3. antimony economically interesting concentrations of antimony in bih are spatially distributed across several areas, regions, or zones: (1) palaeozoic, continental rift-related polymetallic hydrothermal deposits a. the central bosnian ore mountains area (čemernica and fojnica deposits) contains ag, hg and zn. the mineralized zone of čemernica is about 4.5 km long and about 120 m wide. several ore veins were detected there, and the main ore vein was mined to the level of the čemernica stream. analyses show that the čemernica ore is an sb, hg, zn and ag ore enriched in w and au. antimony ore reserves of the a + b + c1 categories contain 299,235 t with contents of 3.3% sb, 5.7% zn, and 96 ppm ag (jurković et al., 2012). further exploration is needed to investigate the extent of mineralization and devise an extraction methodology. b. the southeastern bosnia (podhrusanj) deposit was exploited for antimony ore from 1965 to 1975, during which time only high-grade ore with an antimony content of 4-5% was extracted. reports from 1977 state that the a + b + c1 reserves contain 74,651 t of ore with an average sb content of 3.2% (kubat, 1982; 1995). potential reserves of the c2 category containing about 115,000 t with 1.1% of sb were also reported. based on the metallogenetic analysis, kubat (kubat, 1982; 1995) reported that the podhrusanj region is very interesting for further exploration. the podhrusanj deposit has only been partially explored. mineralized limestones of 0.5 1.5 m thickness appear in the wider area of the deposit containing 410,500 t of a + b + c1 reserves with 3.4% sb. chemical analysis has shown that the ore does not contain as or pb concentrations in heavy liquid analysis (classes -20 +2 mm), and the concentration by flow tables (classes -2 +0 mm) yielded a valuable antimony concentrate with a weight content of 13.9% and an sb content of 43%, with a utilization degree of 81%. (2) oligocene post-collisional deposits of the sava-vardar zone a. the srebrenica field in eastern bosnia (čumavići) consists of a 1m thick and several hundred-metre long main vein containing 7% sb, 2.8% zn, 0.3% pb, 0.05% cu, 0.1% wo3, and 80 g/t ag. preliminary flotation extraction analyses have shown the possibility for concentrating sb, zn and ag, while the pb content is inadequate for economical extraction. the čumavići deposit is only partially explored, showing d2 reserves of 500,000 t (kubat, 1982; 1995). about 100 ha of terrain around the village of čumavići is considered promising due to the identified outcrops of antimony ore. (3) triassic advanced rift-related hydrothermal antimony deposits a. the borovica-vareš-čevljanovići-srednje ore zone (the rupice, and veovača deposits) consists of a complex polymetallic deposit of ba-zn-pb ore with sb and hg. significant geological research in combination with exploration drilling on the rupice deposit was carried out in the second half of the 20th century. exploration results summarized by kurtanović (kurtanović, 1990) revealed reserves of 1,498,011 t with 3% pb and 3,5% zn. kubat (1982; 1995) estimated reserves of sb in the host dolostone of up to tens of thousands of tons with an average antimony content of 4,8%. the veovača deposit, in comparison with the rupice deposit, is characterized by a lower sb content and a slightly higher hg content. ore reserves and resources of all categories are over 6.000.000 t with an average baso4 content of 16,3%, zn of 1,6%, pb of 0,8%, hg of 0,1%, and sb of 0,1% (kubat, 1982; 1995), and there is the possibility of discovering new ore resources in the northeast near the localities of prijeljev and orti. although the veovača location contains primarily ba-zn-pb deposits, relatively low contents of sb and hg should g eologia c roatica borojević šoštarić et al.: the geological potential of antimony, bauxite, fluorite, and magnesite of the central dinarides (bosnia and herzegovina) ... 277 not be neglected in the extraction of useful components from ore. within the borovica-vareščevljanovići-srednje ore zone, the rupice and veovača deposits are classified as prospective deposits containing economic ore reserves (kubat, 1982; 1995). geological exploration is currently ongoing. 5.1.4. fluorites the occurrence of fluorite in bih is small compared with the products of barite or arsenic mineralization. according to the scarce data, only five fluorite deposits were registered: žune and vidrenjak near ljubija, hrmza and meovršje near kreševo, and pećine near gornji vakuf. based on the results of previous research (palinkaš et al., 2016), as well as the conducted field research, the žune deposit in the ljubija ore area in the republic of srpska is the most promising. this deposit is palaeozoic in age and hydrothermal in origin. it is represented by a single subvertical and partially depleted barite-fluorite vein that is several hundred metres long and has a maximum thickness of 10 m. the barite-fluorite vein is hosted by the palaeozoic dolomites, near the contact with the verfen shales and sandstones. the proportion of fluorite is usually about 20%, but it increases with depth, which presents an opportunity for further exploration. the inferred fluorite reserves in this deposit are estimated to be 1.500 t. 5.2. mining potential according to the world mining data (reichl & schatz, 2021), the contribution from bosnia-herzegovina to the mining of antimony, bauxite, fluorspar, and magnesite is comparatively low. between 2015 and 2019, only bauxite (crude ore) and magnesite are listed, ranking bosnia-herzegovina in 18th place out of the 28 bauxite producers and in 22nd place of the 23 magnesite producers (reichl & schatz, 2021). based on the geological potential identified for the four selected commodities, bosniaherzegovina is capable of contributing much more. following the methodology described in section 4.2, the three indicators for mining potential are discussed below, grouped by commodity. 5.2.1. indicator 1: world producer ranking antimony the world production of antimony was 125,478 metric tons in 2019, and at the same time, there was no production at the eu level. looking at the two abandoned mines čemernica and podhursanj, a total of about 374 kt of reserves is estimated (a+b+c1 reserves). assuming a mining loss of 20% and a mine lifetime of 30 years, bih could produce about 350 tons of sb per year. this would make the country europe’s only producer of antimony and place it in 8th position in the world rankings (fig. 4a). magnesite a similar approach for magnesite shows a slightly different picture. the world production of magnesite in 2019 was 27 million metric tons, with about 11% being mined in europe (ec) and bosnia-herzegovina contributing with 1400 tons. looking at the deposits that have been identified as highly graded investment opportunities and only focusing on the abandoned and closed mines, bosnia-herzegovina is capable of producing an additional 36 kt of magnesite1. this would improve the country’s position from 22nd to 16th in the rankings (fig. 4b). similar thoughts would be applicable for the bauxite and fluorite deposits and occurrences, but these are not emphasized here as bosnia-herzegovina already mines more than 1 million metric tons of bauxite per year, and fluorite occurrences will not play a major role based on the currently available data. 5.2.2. indicator 2: self-sustainability a vital topic is the importing of necessary commodities. currently, bosnia-herzegovina does not import any antimony ores and concentrates but imports about 2 to 3 tons of antimony oxides per year. assuming a working processing technique, the stibnite deposits could provide around 2 tons of antimony per year. depending on the field of application, bosnia-herzegovina may reduce the required imports and could even start exporting antimony ores. the european union imports roughly 4 kt of antimony ores and would benefit from a local provider (world trade organization, 2021). imports of magnesite vary, whereby it was 105 tons of sintered magnesite in 2019 (world trade organization, 2021). with the additional tonnage from the mines currently not operating, the magnesite mined in bosnia-herzegovina could reach selfsustainability and bih could become an exporter. numbers on bauxite imports as crude ore are difficult to identify. aluminum ore and concentrate imports amounted to 210 1 taking the available resources upgraded to reserves (amount reduced by 25%) and assuming again a lifetime of 30 years for the underground mine operation, the deposits at blatnica, bukovični jarak and milošev jarak from the teslić and jelovac fields and pločni (from the snjegotina banja luka field) could provide 29 kt. with the open pit mine in ošve reopened, there is a total amount of 36 kt. figure 4a (left). utilizing bosnia-herzegovina's potential for antimony production; b (right). utilizing bosnia-herzegovina's potential for magnesite. g eo lo gi a c ro at ic a geologia croatica 75/2278 kt in 2019, whereas exports were in the range of 32 kt (world trade organization 2021). both values have increased in recent years. it seems unlikely that additional bauxite deposits can dramatically change the import to export ratio but might be able to help maintain the balance. fluorspar imports into bosnia-herzegovina were in the range of 1.4 kt in 2019. the assigned value for this import is about 550.000 usd. utilizing the country’s own fluorite reserves would help to reduce these imports. 5.2.3. indicator 3: economic contribution this potential can also be expressed in monetary units. while the exact prices that could be obtained by selling the products cannot be forecast without proper feasibility studies, including market studies, the potential may be highlighted by simply assuming a perfect market and ideal conditions. prices for antimony and raw magnesite are currently listed at 6586 usd/t and 89 usd/t, respectively (bundesanstalt für geowissenschaften und rohstoffe (bgr) 2021). all deposits examined here are underground mines, except the one in ošve. to estimate the operating costs and capital costs for the mines, figures from an estimator’s guide (infomine usa, inc. 2016) are extrapolated to account for the estimated production tonnage and updated to current values by assuming an inflation factor of 8.5%. for all subsurface mines, a mechanized cut and fill operation with adit access is assumed. this seems feasible, as all deposits in question are irregular veins or of vein-type. the open pit mine is assumed to have a waste to ore stripping ratio of 8:1. when combining these estimates with the production tonnages from the previous paragraph, the theoretically achievable prices and the estimated costs and, thus, a potential net profit value can be calculated (table 2). the calculation is based on currently stated reserves and compared to a theoretical tonnage after additional exploration. the reserves and resources upgraded to reserves are taken from the investrm reports are adjusted to account for mining losses. costs are based on figures from infomine but adjusted to the production rates for an estimated lifetime of 30 years per deposit. together with prices for antimony and magnesite, a simple npv calculation is performed. further assumptions: 12% discount rate and a lom of 30 years, no price or cost increases over the years; re-occurring capital costs every 10 years (50%, 25%, 25%). for čemernica, a positive value can be achieved if additional metals (zn and ag) are mined and sold. the focus should be on processing to ensure the inclusion of zn and ag in the product portfolio. looking at the overall economy of bosnia and herzegovina, mines could contribute ten percent of the profit as corporate income tax. in podhrusanj, the loss can be halved if additional exploration can prove 410 kt. further engineering to reduce the capital costs and a market study on price development may produce a positive npv. the open pit mine in ošve can achieve a significant improvement (factor 10) in the mineability if reserves can be upgraded from the c1 and c2 to the a and b categories. additional improvements in mine design can reduce operating and capital costs. for the telić and banja luka fields, the calculation shows that currently calculated losses can be halved if the deposits per field could be combined. using these synergies together with a reserve re-classification and a proper mine design, the operations may become very profitable. additionally, attention should be paid to the inclusion of a refinement step to improve the final product and increase the achievable prices. comparing average prices for antimony and magnesite between 2016 to 2020 with values from june 2020 to may 2021, an increase of 2% (antimony) and 1.8% (magnesite) can be seen (bundesanstalt für geowissenschaften und rohstoffe (bgr) 2021). as described, antimony deposits also host zn, ag or, in the case of rupice, baso4. a closer analysis of the processability of the extracted ore could enhance the product portfolio of the mining sites in rupice, čemernica, and srebenica and thus boost their profitability. fluorspar deposits currently do not provide enough data for a similar calculation, and most bauxite mines highlighted in the fipa brochure are already operational. therefore, both commodities are not included in this subsection. all costs and price figures in this chapter are based on profound assumptions but would require further market studies (true prices, real demand) and costs (re-opening the abandoned mines, processing, employees, and energy). furthermore, more detailed mine plans are necessary to estimate mining losses and production figures. in some cases, e.g. podhrusanj, additional exploration could improve the inferred reserves (see section 5.1 for comparison) but will generate some costs. for all mines, feasibility studies would deliver more realistic estimations about the profitability and might provide better profit values. for all deposits described here, two different courses of action can be taken: starting exploitation or continuing extraction by renewing existing mining permits. either way, a more profound financial calculation on a micro-economic level is necessary, as the most critical parameter for the exploitation is the financial feasibility of a mining project. a major decision driver for a company to start or continue mining of a particular deposit is the ability of the mine to create a profit. it is no easy task to answer the question about the true mineability of a mine or deposit. the general process of evaluating mine investment opportunities usually includes the assessment of four main, interrelated factors: the ore reserves, the cut-off grade (or quality), the mine size, and the production costs (gentry & o’neil, 1984). for mining financial calculations, investors require a sound and reliable data base. this data needs to cover all the main factors of production, including the deposit and relevant geological data. especially for foreign investors, it can be a very time consuming and exhausting task to find consistent data on economic and social figures or deal with information about concessions or local political strategies. the investrm decision making tool offers a quick, user-friendly, and easy way to access and gather all the necessary information in a comprehensive report (haindl, 2020). 6. conclusion a total of 126 deposits and occurrences of antimony, bauxite, fluorspar, and magnesite occurrences in bosnia and herzegovina have been validated using the developed investrm methodology to determine their exploration and exploitation potential. the developed investrm methodology consists of the following steps: (1) preparation of the geological data templates in line with international raw materials datasets (m4eu, egdi) for 126 deposits/occurrences; (2) evaluation and verification of the geological data in order to estimate the investment potential using criteria extracted from the world risk report (2017) and specific investrm parameters; g eologia c roatica borojević šoštarić et al.: the geological potential of antimony, bauxite, fluorite, and magnesite of the central dinarides (bosnia and herzegovina) ... 279 (3) ranking deposits according to the quality of the geological data (complete and relevant datasets from a geological data template) and data quantity (reserves, available past exploration data), as well as social licensing, environmental management, and project permitting, into ranks a, b or c, and (4) identification of the 10+ perspective deposits (barite-fluorite vein-type deposit žune; polymetallic antimony deposits čemernica and podhrusanj, antimony fields srebrenica and rupice; magnesite fields kladanj, banja luka, teslić and novi šeher and bauxite regions vlasenica-srebrenica, grmeč mountain deposits in una-sana region and south bosnia regions from posušje to trebinje; appendix 3, table 1-4) meeting all predefined criteria and parameters. analysis shows that a significant potential in primary critical raw materials such as bauxite (56 mt), magnesite (4 mt), and antimony (0.2 mt) exists in bosnia and hercegovina. however, current production places bih in 18th position in the world for bauxite and 22nd for magnesite, with no production in antimony or fluorspar. metallogenically, these commodities are associated with several large and distinctive tectonostratigraphic units within the dinarides: (i) karst bauxites, predominantly hosted by the external dinarides (adriatic carbonate platform) and the bosnian flysch of the internal dinarides; (ii) magnesite deposits of kraubath-type exclusively hosted by the dinaric ophiolitic zone, and (iii) antimony within polymetallic deposits associated with palaeozoic continental rifting, triassic advanced rifting and oligocene post-collisional events of the sava-vardar zone. three indicators: the world producer ranking, self-sustainability, and economic contribution, are included in the analysis of the country’s mining potential. bosnia-herzegovina could play a major role in europe’s strategy to become self-sustaining in the supply of critical raw materials. the brief economic discussion shows that there is a need for investments in geological prospection and engineering to transform the abandoned mines into operational sites and prepare feasibility studies. antimony and fluorspar occurrences are part of the polymetallic deposits and can add value to low-feasibilty deposits. large magnesite and bauxite regions provide opportunities for additional exploration and improvements in the exploitation process. considering all the facts, investments in exploration and mining could boost bih’s economy and create value not only for the country itself, as it could be self-sustaining in antimony and magnesite, but also as a supplier for europe. acknowledgement this work has been financially supported by eit rawmaterials project no. 17051 invest rm: multifactor model for investments in the raw material sector, a part of the horizon 2020 program. we would like to thank the invest rm team https://investrm.eu/ for continuous fieldwork support, helpful advice, and discussion. proof reading by native english speaker, isabella merschdorf is highly appreciated. references anton a., burić, p., dangić, a., ilić, m., jelić, m., jovanović, č., jovanović, p., kapeler, i., karamata, s., kubat, i., miladinović, d., olujić, j., pamić, j., podubsky, v., ramović, m., sunarić-pamić, o., vakanjac, b., varićak, d., vasiljević, r., vujović, m. & živanović, d. (1979): ležišta nemetala [non-metallic deposits in bosnian]. – in: čičić, s. (ed.): mineralne sirovine bosne i hercegovine: ležišta nemetala [mineral raw materials of bosnia and herzegovina], vol. 1/2, 2 volumes, 236–447. bodulić, g., jovanović, r., jovanović, p., jurić, m., đurić, s., kubat, i. & kulenović, e. (1979): ležišta crnih metala [ferrous metal deposits – in bosnian].– in: čičić, s. (ed.): mineralne sirovine bosne i hercegovine: ležišta nemetala [mineral raw materials of bosnia and herzegovina: non-metallic deposits – in bosnian], vol. 2/4. 2 volumes, 215–414. borojević šoštarić, s., neubauer, f., handler, r. & palinkaš, l.a. (2012): tectonothermal history of the basement rocks within the nw dinarides: new40 ar/39 ar ages and synthesis.– geologica carpathica, 63/6, 441–452. doi: 10.2478/v10096-012-0034-2 borojević šoštarić, s., palinkaš, l.a., strmić palinkaš, s., bermanec, v., neubauer, f., spangenberg, j. & prochaska, w. (2009): origin of siderite mineralisation in petrova and trgovska gora mts., nw dinarides.– miner. petrol., 97/1–2, 111–128. doi: 10.1007/s00710-009-0065-2 budeš, i., galić, i. & dragičević, i. (2018): research of bauxite deposits from underground mining works.– mgpb, 33/3, 95–110. doi: 10.17794/rgn.2018.3.10 bundesanstalt für geowissenschaften und rohstoffe (2021): preismonitor. rohstoff-preismonitor.– edited by deutsche rohstoffagentur (dera) in der bgr. available online at https://www.deutsche-rohstoffagentur.de/dera/de/produkte/rohstoffpreise/preismonitor/preismonitor_node.html, (checked on 8/27/2021) burić, p. & živaljević, t. (1979): ležišta boksita [bauxite deposits – in bosnian].– in: čičić, s. (ed.): mineralne sirovine bosne i hercegovine: ležišta obojenih metala [mineral raw materials of bosnia and herzegovina: non-ferrous metals – in bosnian]. geoinženjering, sarajevo, vol 2/3, 123–214. čičić, s. (ed.) (1979): mineralne sirovine bosne i hercegovine: ležišta nemetala [mineral raw materials of bosnia and herzegovina: non-metallic deposits – in bosnian].– geoinženjering sarajevo. 2 volumes. čičić, s. (ed.) (1979): mineralne sirovine bosne i hercegovine: ležišta obojenih metala [mineral raw materials of bosnia and herzegovina: non-ferrous metals – in bosnian].– geoinženjering sarajevo. 2 volumes. sarajevo. cvijić, r. (2004): geomenadžment u funkciji korišćenja i razvoja mineralnih resursa ljubijske metalogenetske oblasti [geo-management as production and development tool of mineral raw materials in ljubija metallogeny area – in bosnian].– rudarski institut, prijedor, 348 p. dangić, a. (1978): model evolucije hidrotermalne aktivnosti u rudonosnom području srebrenice [model of evolution of hydrothermal activity in the ore – bearing area of srebrenica – in bosnian].– in: ix. kongres geologa jugoslavije. sarajevo, 565–571. dangić, a. (1988): kaolinization of bauxite: a study of the vlasenica bauxite area, yugoslavia. ii. alteration of oolites.– clays and clay minerals, 36/5, 439–447. doi: 10.1346/ccmn.1988.0360509 dangić, a. (2015): mineralogy, geochemistry and epigenesis of bauxites in inner dinarides.– herald geological, 361–30. dimitrijević, m.d. (1982): dinarides: an outline of the tectonics.– earth evol. sci., 2/1, 4–23. dimitrijević, m.d. (1997): geology of yugoslavia.– geol. survey gemini special publication, belgrade, 187 p. dragičević, i., papešt, j. & pavičić, i. (2019): geological settings of the jajce bauxite bearing-area (bosnia and herzegovina).– journal of maps, 15/2, 744–750. doi: 10.1080/17445647.2019.1664652 european commission (2011): tackling the challenges in commodity markets and on raw materials. communication from the commission to the european parliament, the council, the european economic and social committee and the committee of the regions. 25.– european commission, brussels. european commission (2017): on the 2017 list of critical raw materials for the eu. communication from the commission to the european parliament, the council, the european economic and social committee and the committee of the regions. 490.– european commission, brussels. european commission (2020): study on the eu’s list of critical raw materials – final report.– publications office of the european union, luxembourg. doi: 10.2873/11619 gentry, d.w. & o’neil, t.j. (1984): mine investment analysis.– society of mining engineers of american institute of mining, metallurgical, and petroleum engineers inc, new york. grubić, a. (1975): geology of yugoslavian bauxite.– in: serbian academy of sciences and arts. special edition, book cdlxxxiii. belgrade, 60–65. grubić, a., cvijić, r., milošević, a. & čeleić, m. (2016): interpreters of the metalogenetic map of the ljubjian ore region acelor mittal prijedor.– fund of technical documentation mining institute prijedor and arcelormittal prijedor, 91 p. haindl, a. (2020): investrm – investieren in rohstoffe am balkan.– berg huettenmaenn. monatsh., 165/4, 211–215. doi: 10.1007/s00501-020-00959-2. hodžić, n. & djedović, m. (2014): elaborat o klasifikaciji, kategorizaciji i proračunu rezervi magnezita ležišta “konjuh” sa stanjem [study on the classification, categorization and calculation of magnesite reserves of the “konjuh” deposit – in bosnian].– fund of the technical documentation, rudar d.o.o. tuzla. ilić, m. & jelić, m. (1979): magneziti [magnesites– in bosnian– in: čičić, s. (ed.): mineralne sirovine bosne i hercegovine: ležišta nemetala [mineral raw materials of bosnia and herzegovina: non-metallic deposits – in bosnian]. geoinženjering, sarajevo, vol. 1/2, 273–309. g eo lo gi a c ro at ic a geologia croatica 75/2280 infomine usa, inc. (2016): mine and milll equipment costs: an estimator’s guide.– infomine usa, inc. costmine division. investrm-team (2020): investment opportunities in raw materials in bosnia and herzegovina. results of the project invest rawmaterials – multifactor model for investments in the raw material sector, case study bosnia and herzegovina. with assistance of fipa, eit raw materials. council of ministers of bosnia and herzegovina foreign investment promotion agency of bih. -available online at: http:// www.fipa.gov.ba/publikacije_materijali/brosure/fipa%20brochure%20 23.11.2020.pdf (checked on 9/29/2021) janisch, a. (2014): ressourcenverfügbarkeit, bergtechnische charakterisierung und bergbauplanungskonzepte ausgewählter vorkommen eu-kritischer rohstoffe in österreich. masterarbeit. lehrstuhl für bergbaukunde, bergtechnik und bergwirtschaft. montanuniversität leoben, leoben. jašarević, e., džindo, m., šabović, a. & taletović, n. (2013): projekat detaljnih geoloških istraživanja ležišta olova, cinka i barita u istražnom polju, rupice-juraševac-brestić [design on detailed geological explorations of lead, zinc and barite deposits in the ‚‘rupice-juraševac-brestić‘‘ exploration field – in bosnian].– institute, tuzla. jejina, t. & cvijić, r. (1977): preliminary design of mine and iron ore separation vidernjak, mine ljubija: book i, geological part.– fund of technical documentation, ržr ljubija prijedor. jelić, m. (1979): florit [fluorite – in bosnian].– in čičić, s. (ed.): mineralne sirovine bosne i hercegovine: ležišta nemetala [mineral raw materials of bosnia and herzegovina: non-metallic deposits – in bosnian], vol. 1/2. 2 volumes, 243–244. jeremić, m. (1958): baritno-fluoritno ležište žune kod ljubije [barite-fluorite deposit žune-dolinac near ljubija – in serbian].– rudarsko-metalurški zbornik, 4. jovanović, r. (1979): ležišta željezne rude centralne bosne i hercegovine, mineralne sirovine bosne i hercegovine [iron ore deposits of central bosnia and herzegovina, mineral raw materials of bosnia and herzegovina – in bosnian].– geoengineering sarajevo. jurić m. (1973): sanski paleozoik sinteza poznavanja rudnih pojava [sana region palaeozoicsynthesis of knowledge about ore phenomena – in bosnian].– book i, ii, iii.fund of professional documentation, arcelormittal, prijedor. jurković, i. (1961): zavod za geološka istraživanja i ispitivanja građevinskog materiala i tla [institute for geological research and testing of construction materials and soils – in bosnian].– gelogical herald, 5, 199–241. jurković, i., palinkaš, l.a., garašić, v. & strmić palinkaš, s. (2012): genesis of vein-stockwork cryptocrystalline magensite from the dinaride ophiolites.– ofioliti, 37/1, 13–26. doi: 10.4454/ofioliti.v37i1.403. jurković, i., ramović, m. & zec, f. (1999): chemical and geochemical characteristics of the čemernica antimonite deposit in the mid-bosnian schist mountains.– in: rudarsko-geološko-naftni zbornik, 11/1, 1–16. kubat, i. (1982): metalogenija i prognoza čvrstih mineralnih sirovina u trijasu bosne i hercegovine [metallogeny and prognoses of the mineral raw minerals in triassic of the bosnia and herzegovina – in bosnian].– in: spec. publ. geol. glasnik, 11, sarajevo, 1–149. kubat, i. (1995): metalogenija antimona i žive u bih i mogućnost proizvodnje i prerade [metallogeny of antimony and mercury in bih and the possibility of production and processing – in bosnian].– zavod za geologiju, sarajevo. kubat, i. & đorđević, d. (1973): mineralizacija kalaja u okviru ležišta olova i cinka “srebrenica” u istočnoj bosni [tin mineralization within the “srebrenica” lead and zinc deposits in eastern bosnia – in bosnian].– gelogical herald, 17, 325–336. kurtanović, r. (1990): godišnji izvještaj o regionalnim geološkim istraživanjima kompleksnih zn i baso4 mineralizacija na lokalitetu rupice kod vareša za 1989 godinu [annual report on regional geological research of complex zn and baso4 mineralizations at the rupica site near vareš for 1989 – in bosnian].– fund of technical documentation, federal geological survey, sarajevo. marjoribanks, r.w. (1997): geological methods in mineral exploration and mining.– chapman & hall, london. minerals4eu http://minerals4eu.brgm-rec.fr/minerals4eu/ (checked on 8/27/2021) mitrović, d. (ed.) (2011): mineralne sirovine republike srpske [mineral raw materials of the republic of srpska – in bosnian].– ministry of industry, energy and mining; republic geological survey, zvornik. neukirchen, f. & ries, g. (2014): die welt der rohstoffe. [world of raw materials – in german].– springer spektrum, berlin [u.a.]. operta, m. & bušatlić, n. (2018): contribution to the knowlede of the magnesite deposits in bosnia and herzegovina.– geografski pregled, 39, 107–122. operta, m. & hyseni, s. (2016): mineral raw materials metallogenic zone borovica-vares-cevljanovici (bih).– international journal of technology enhancements and emerging engineering research, 4/2, 16–20. palinkaš, l., borojević šoštarić, s., strmić palinkaš, s., prochaska, w., pécskay, z., neubauer, f. & spangenberg, j.e. (2016): the ljubija geothermal field: a herald of the pangea break-up (nw bosnia and herzegovina).– geologia croatica, 69/1, 3–30. doi: 10.4154/gc.2016.02 palinkaš, l. & jurković, i. (1994): lanthanide geochemistry and fluid inclusion peculiarities of the fluorite from the barite deposits south of kreševo.– geologia croatica, 47/1, 103–115. strmić palinkaš, s., spangenberg, j.e. & palinkaš, l.a. (2009): organic and inorganic geochemistry of ljubija siderite deposits, nw bosnia and herzegovina.– miner. deposita, 44/8, 893–913. doi: 10.1007/s00126-009-0249-z pamić, j. (1982): some geological problems of the dinaridic ophiolites and their associations.– earth evol. sci., 2, 30–35. pamić, j., gušić, i. & jelaska, v. (1998): geodynamic evolution of the central dinarides.– tectonophysics, 297, 251–268. pavičić, i., dragičević, i. & ivkić, i. (2018): high-resolution 3d geological model of the bauxite-bearing area crvene stijene (jajce, bosnia and herzegovina) and its application in ongoing research and mining.– geological quarterly, 62/1, doi: 10.7306/gq.1396 promine http://www.europe-geology.eu/promine/ (checked on 8/27/2021) ramović, m. (1963): rudne parageneze u oblasti srebrenice (istočna bosna) [ore paragenesis in the srebrenica area (eastern bosnia) – in bosnian].– spec. publ. geol. glasnik, 1, 1–96. ramović, m., kubat, i., veljković, d., kulenović, e. & đurić, s. (1979): cink, olovo i srebro [zinc, lead and silver – in bosian].– in: čičić, s. (ed.): mineralne sirovine bosne i hercegovine: ležišta obojenih metala [mineral raw materials of bosnia and herzegovina: non-ferrous metals – in bosnian].– geoinženjering, sarajevo, vol 2/3, 9–97. reichl, c. & schatz, m. (2021): world mining data 2021. iron and ferro-alloy metals, non-ferrous metals, precious metals, industrial minerals, mineral fuels. – federal ministry of agriculture, regions and tourism, republic of austria, vienna. minerals production, 36, checked on 5/25/2021. rulebook on classification, categorization, and calculation of solid mineral raw material reserves and keeping records on them (official gazette of the fbih no. 36/12). schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s. & schuster, r. (2008): the alpine-carpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss j. geosci., 101/1, 139–183. doi: 10.1007/s00015-008-1247-3. sunarić-pamić, o. & pamić, j. (1988): žični magneziti ofiolitske zone dinarida u bosni i njihova geneza [magnesites from the dinaride ophiolite zone in bosnia and their genesis – in bosnian].– spec. publ. geol. glasnik, 22, 1–173. tomljenović, b., csontos, l., márton, e. & márton, p. (2008): tectonic evolution of the northwestern internal dinarides as constrained by structures and rotation of medvednica mountains, north croatia.– geological society special publications, 298, 145–167. todorović, m. (2016): geološko petrološke i mineraloške karakteristike rudnog polja srebrenica-milići [geological-petrological and mineralogical characteristics of the srebrenica-milići ore field – in bosnian].– fund of technical documentation, boksit milići d.o.o. wahl, s. von (1990-1991): bergwirtschaft. [mining economics – in german].– verl. glückauf, essen. world trade organization (2021): world integrated trade solution (wits). available online at https://wits.worldbank.org/default.aspx?lang=en (checked on 8/27/2021) zarić, p., janković, s., radosavljević, s. & đorċević, d. (2000): tin minerals and tin mineralization of the pb-zn-sb-ag ore deposits of the srebrenica orefield.– in: proc. of the international symposium geology and metallogeny of the dinarides and the vardar zone, vol. 1. banja luka, 425–434. g eologia c roatica borojević šoštarić et al.: the geological potential of antimony, bauxite, fluorite, and magnesite of the central dinarides (bosnia and herzegovina) ... 281 appendix 1 table 1. selection criteria parameters – geological criteria. table 2. selection criteria parameters – social licencing, environmental management, project permitting, skills availability. g eo lo gi a c ro at ic a geologia croatica 75/2282 ap pe nd ix 2 . c rm d ep os its in b os ni a an d he rz eg ov in a ta bl e 1. a nt im on y de po si ts in b os ni a an d h er ze go vi na (d at a co m pl ie d af te r r ef er en ce s us ed in v er ifi ca tio n an d ev al ua tio n ph as e: c vi jić (2 00 4) ; č ič ić (1 97 9) ; d a n g ić (1 97 8) ; g ru bi ć et a l., (2 01 6) ; j a ša re vi ć et a l., (2 01 3) ; j u ri ć (1 97 3) ; ku ba t et a l. (1 97 3) ; k u ba t (1 99 5) ; m it ro vi ć (2 01 1) ; p a li n ka š et a l., (2 00 9; 2 01 6) ; r a m o vi ć (1 96 3) ; t o d o ro vi ć (2 01 6) . a re a d ep os it ke y to fi gu re 1 ag e sh ap e m in er al co m m od ity sb (% ) pb +z n (% ) re se rv es (t )r es ou rs es (t ) re se rv es + re so ur se s (a +b +c ₁+ c₂ +d ) d at a le ve l q ua nt ity pe rs pe ctiv ity so ci al lic en ci ng en vi ro nm en ta l m an ag em en t pr oj ec t pe rm itt in g (a +b +c ₁) (c ₂+ d ) internal dinarides ce nt ra l b os ni a ca nt on če m er ni ca 1 ca rb on ife ro us , pe rm ia n irr eg ul ar , v ei n a nt im on yst ib ni te sb -z nh ga sag 4. 0 11 ,9 35 29 9, 23 4 a a + b b b to tin ov ac -v id uš a 2 pa le oz oi c sb -z nh ga s b c b c c re pu bl ic o f sr pa sk a (f ie ld lj ub ija ) fi el d lj ub ija 3 pa le oz oi c+ tr ia ss ic irr eg ul ar , v ei n a nt im on yst ib ni te pb -z nsb -h g 1, 10 0, 00 0 2, 00 0, 00 0 3, 10 0, 00 0 b b po dh ru sa nj 4 pa le oz oi cm id dl e tr ia ss ic sb 1. 1– 3. 2 74 ,6 51 11 5, 00 0 a a + b c c ze ni ca -d ob oj ca nt on fi el d ru pi ce 5 pa le oz oi cm id dl e tr ia ss ic la ye r, ve in a nt im on yst ib ni te ba -p bzn -a gau sb -h g >1 0, 00 0 3, 00 0, 00 0 a ru pi ce 6 m id dl e tr ia ss ic irr eg ul ar , v ei n 4. 8 >1 0, 00 0 a a + a a a ri d 7 la ye r 7 1, 00 0, 00 0 a b a b b ve lik i d o 8 la ye r, ve in 4. 5– 7 50 0, 00 0 a b a b b kr iž 9 la ye r, irr eg ul ar 4. 0– 8 1, 50 0, 00 0 a b a b b ve ov ač a 10 v ei n ba -p bzn -s bh g 0. 1 2. 3 6, 00 0, 00 0 a a a a a re pu bl ic o f sr ps ka po dk oz ar a 11 m id dl e tr ia ss ic irr eg ul ar , v ei n a nt im on yst ib ni te sb -p bzn -a sau -h g b b a a a fi el d sr eb re ni ca 12 o lig oc en e irr eg ul ar , v ei n a nt im on yst ib ni te pb -z nsb -a gau 23 ,0 00 ,0 00 a /b li sa c 13 20 ,0 00 ,0 00 a /b b a a a vi tlo va c 14 pb -z nsb -a gau -a s 2, 00 0, 00 0 a /b b a a a ču m av ić 15 1, 00 0, 00 0 a /b b a a a g eologia c roatica borojević šoštarić et al.: the geological potential of antimony, bauxite, fluorite, and magnesite of the central dinarides (bosnia and herzegovina) ... 283 ta bl e 2. b au xi te d ep os its in b os ni a an d h er ze go vi na (d at a co m pl ie d af te r r ef er en ce s u se d in v er ifi ca tio n an d ev al ua tio n ph as e: b u d eš e t a l., (2 01 8) ; č ič ić (1 97 9) ; d a n g ić (1 98 8) ; d a n g ić (2 01 5) ; g ru bi ć, a ., ( 19 75 ); m it ro vi ć (2 01 1) ; p av ič ić et a l., (2 01 8) ). a re a d ep os it ke y to fi gu re 1 en be de d be tw ee n sh ap e m in er al ch em ic al c om po si tio n re se rv es re so ur se s d at a le ve l q ua nt ity pe rs pe ct iv ity so ci al lic en ci ng en vi ro n m en ta l m an ag em en t pr oj ec t pe rm ittin g external dinaride bauxites a l 2o 3 ( % ) si o 2 ( % ) fe 2o 3 ( % ) ti o 2 ( % ) a +b +c ₁ c₂ so ut h bo sn ia re gi on (h er ce go vi na ) h er ze go vi na -n er et va ca nt on (č itl uk re gi on ) bl at ni ca -l ok vi ce 1 u pp er c re ta ce ou spa le oge ne le ns oi da l, la ye r bo eh m ite 53 .4 5. 4 1, 07 0, 95 8 a a + b c c kr eh in g ra da cbl iz an ci 2 49 .2 6. 0 15 9, 65 3 a b b c c m am ić i-r as no -h am zi ći 3 50 .2 9. 7 4, 76 5 a c b c c o šl ja rikr iv od ol 4 46 .3 11 .3 94 ,6 30 a b b c c sl už an j 5 no d at a c c b c c vi tin ali pn o 6 u pp er c re ta ce ou s le ns oi da l 41 .7 18 .3 42 7, 27 5 a b b c c w es t h er ze go vi na ca nt on (l iš tic a re gi on ) cr ne lo kv eki da čk e nj iv e 7 u pp er c re ta ce ou spa le oge ne le ns oi da l, la ye r bo eh m ite 51 .0 5. 3 1, 54 5, 32 2 a a + b c c re sn ic ag ra bo va d ra ga 8 55 .5 8. 1 25 ,1 80 a b b c c u za ric i-k ne žp ol je 9 56 .3 3. 8 15 7, 02 0 a b b c c va rd a pl an in a 10 54 .4 3. 4 81 6, 30 1 a a b c c tr nsl iš ko vi ća lo kv e 11 u pp er c re ta ce ou sn eo ge ne 30 -4 5 14 -3 3 19 7, 00 0 a b b c c h er ze go vi na -n er et va ca nt on (m os ta r r eg io n) žo vn ic a 12 u pp er c re ta ce ou s le ns oi da l, la ye r bo eh m ite 41 .7 18 .1 no d at a c c b c c ja se nj an i 13 u pp er c re ta ce ou seo ce ne g ib bs ite , bo eh m ite 46 .5 4. 2 35 ,7 00 a b b c c w es t h er ze go vi na ca nt on (p os uš je re gi on ) kr st ač ece ro vi d oc i 14 u pp er c re ta ce ou spa le oge ne le ns oi da l, la ye r bo eh m ite 55 .6 3. 7 1, 45 9, 50 7 a a + b c c m ra tn ja ča -m ed in e st an in e 15 56 .5 3. 5 1, 64 8, 42 7 a a + b c c po dz av el in -v in ic a 16 51 .4 7. 5 23 ,1 50 a b b c c st ud en a vr ila 17 11 1, 13 0 a a + a b b tr eb is to vo -s ob ač 18 52 .0 5. 7 90 1, 88 0 a a b c c vi nj an i 19 52 .0 5. 7 55 8, 67 9 a a b c c vo lu ja kka di m 20 43 .0 13 .1 48 7, 26 0 a a b c c vu či po lje 21 53 .8 1. 7 25 2, 74 0 a b b c c fi el d st ud en a vr ila -z ag or je 22 50 .2 6. 5 11 1, 13 0 a a + a b b h er ze go vi na -n er et va ca nt on (s to la c re gi on ) bi vo lje b rd od om an ov ić i 23 u pp er c re ta ce ou spa le oge ne le ns oi da l, la ye r bo eh m ite 45 .1 13 .7 62 ,6 00 a b b c c d ab ric a 24 47 .7 13 .1 1, 06 5, 69 5 a a + b c c g or nj i b rš ta ni k 25 47 .6 10 .9 28 6, 44 3 a b b c c h rg ud 26 39 –4 5 6– 37 20 ,0 00 a b b c c po pl at 27 49 .4 0. 1 25 ,4 20 a b b c c h od ov o 28 u pp er c re ta ce ou seo ce ne 50 .1 2. 2 42 ,5 00 a b b c c re pu bl ic o f s rp sk a u dr ež nj e 29 u pp er c re ta ce ou seo ce ne le ns oi da l, la ye r g ib bs ite , bo eh m ite 47 .7 13 .3 42 1, 00 0 a b a a a vi du ša 30 u pp er ju ra ss ic sa dd le -s ha pe d 44 –6 2 2– 10 11 -1 9 16 5, 06 2 a b a a a n or th w es te rn b os ni a re gi on (b os an sk a kr aj in a) u na -s an a ca nt on bj el aj 31 m id dl e tr ia ss ic le ns oi da l, la ye r g ib bs ite , bo eh m ite 29 .4 –5 7. 2 7. 5– 40 .2 7. 3– 15 .5 2. 6– 3. 0 60 ,0 00 a b b c c ve lik i s ko ča j 32 bo eh m ite 45 .3 –6 9. 2 7. 6– 24 .0 2. 3– 19 .5 0 .4 –2 .9 no d at a b c b c c kr nj eu ša -b ra vs ki v rh -c rn i v rh 33 u pp er ju ra ss ic irr eg ul ar le ns es , irr eg ul ar n es ts 57 .7 5– 68 .8 2. 9– 7. 7 9. 9– 11 .6 2. 8– 3. 2 10 ,5 00 ,0 00 a a + b c a pr ito ka -t ih ot in atr ov rh 34 u pp er c re ta ce ou s le ns oi da l, la ye r 62 –7 4. 5 1– 5 6. 9– 15 .8 3. 0 10 ,0 00 ,0 00 a a + b c c su va ja -š ol aj a 35 g ib bs ite , bo eh m ite 55 –6 0 0– 5 27 5, 00 0 1, 49 9, 10 0 a b b c c ce nt ra l b os ni a re gi on (j aj ce ) g eo lo gi a c ro at ic a geologia croatica 75/2284 internal dinaride bauxite ce nt ra l b os ni a ca nt on be šp el j-c rv en e st ije ne 36 u pp er lo w er cr et ac eo us sa dd le -s ha pe d bo eh m ite 55 .0 –6 0. 0 1. 0– 4. 0 <2 1. 0 3. 0 11 6, 37 5 30 5, 00 0 a a a a a po lja na 37 u pp er lo w er cr et ac eo us irr eg ul ar a nd le ns oi da l 53 .0 –6 2. 0 0. 5– 4. 0 <2 1. 0– 30 .0 2– 3 30 0, 00 0 a a a a a ea st b os ni a re gi on (v la se ni ca -s re br en ic a) (3 849 ) re pu bl ic o f s rp sk a pa le ž 38 m id dl e tr ia ss ic ta bu la r bo eh m ite 42 .0 –5 5. 0 1. 0– 20 .0 17 .0 –3 0. 0 2. 0– 3. 5 no d at a b c a a a št ed ra 39 irr eg ul ar 41 –5 5 5– 20 20 –3 4 no d at a b c a c a že da nj sk o 40 m id dl e tr ia ss ic u pp er cr et ac eo us irr eg ul ar 34 –5 3 2– 37 60 ,0 00 b b a c a ku tu ze ro 41 44 –5 6 2– 12 no d at a c c a c a pr ib oj ev ić i 42 37 .8 –6 4. 6 25 0, 00 0 b b a c a cr ve ne st ije ne -v la se ni ca 43 50 .0 28 .0 8. 0 4, 82 7, 80 9 a a + a a a d ra go šn ic a 44 52 .1 7. 0 26 .0 12 2, 68 0 b b a c a g er ov i 45 n. a. no d at a c c a c a ko st ur i 46 53 .1 6. 3 26 .3 2. 6 5, 81 3, 64 4 a a + a a a po db ra ća n 47 ta bu la r/ le ns oi da l n. a. 2, 30 0, 00 0 50 0, 00 0 a a + a a a šu m ar ni ca 48 m id dl e tr ia ss ic n eo ge ne ta bu la r/ le ns oi da l 50 .9 6. 3 29 .0 2. 8 5, 00 0, 00 0 a a + a a a pa le ž iibr ać an 49 lo w er c re ta ce ou sn eo ge ne le ns es 51 .8 10 .3 20 -3 4 41 5, 33 0 a a + a a a ta bl e 2. c on tin ue d. g eologia c roatica borojević šoštarić et al.: the geological potential of antimony, bauxite, fluorite, and magnesite of the central dinarides (bosnia and herzegovina) ... 285 ta bl e 3. fl uo rit e de po si ts in b os ni a an d h er ze go vi na (d at a co m pl ie d af te r r ef er en ce s u se d in v er ifi ca tio n an d ev al ua tio n ph as e: c vi jić (2 00 4) ; č ič ić (1 97 9) ; g ru bi ć et a l., (2 01 6) ; j ej in a e t a l., (1 97 7) ; j u ri ć (1 97 3) ; j u rk o vi ć (1 96 1) ; k u ba t (1 99 5) ; m it ro vi ć (2 01 1) ; p a li n ka š et a l., (2 00 9; 2 01 6) ). ita lli c st an ds fo r c 1+ c 2 re so ur se s. a re a d ep os it ke y to fi gu re 1 ag e sh ap e m in er al ch em ic al c om po si tio n re se rv es re so ur se s d at a le ve l q ua nt ity pe rs pe ct iv ity so ci al lic en ci ng en vi ro nm en ta l m an ag em en t pr oj ec t pe rm ittin g m go (% ) si o 2 ( % ) ca o (% ) r 2 o 3( % ) a +b +c ₁ c₂ o r c 1+ c 2 internal dinaridestu zl a ca nt on (f ie ld k la da nj ) m ag ne si te f ie ld k la da nj 1 pa le oc en e irr eg ul ar , v ei nty pe m ag ne si te 19 3, 48 4 a 20 0, 78 4 59 ,8 00 a m ilj ev ic a 2 a + a a a ze ni či ca 3 pa le oc en e 19 .8 –4 7. 8 0. 4– 3. 56 0. 3– 2. 4 7, 30 0 55 ,0 00 a b a b b d rin ja ča 4 19 .8 –4 7. 8 1. 81 –4 .0 1 1. 3– 5. 3 4, 80 0 a c a b b ze ni ca -d ob oj ca nt on (f ie ld m oš ev ac ) m ag ne si te f ie ld m oš ev ac 5 pa le oc en e irr eg ul ar , v ei nty pe m ag ne si te 28 .5 –4 5. 1 0. 4– 36 .9 0. 4– 11 .6 0. 6– 3. 3 11 6, 00 0 2, 90 0 43 ,0 00 45 ,0 00 24 ,0 00 10 ,0 00 10 ,0 00 20 ,0 00 46 4, 90 0 a /b bo rik 6 12 .5 19 4, 00 0 b a b c c m oš ev ac 7 3. 11 –2 7. 0 b a b c c pa kl en ic a 8 36 .9 b c b c c ša hm an sk a ba šć a 9 10 .1 b b b c c d iv an 1 10 13 .2 b b b c c d iv an 2 11 b b b c c d as ka 12 0. 4 b b/ c b c c be ša p ot ok 13 0. 8 b b/ c b c c d ru m 14 b b b c c ze ni ca -d ob oj ca nt on (f ie ld n ov i š eh er ) m ag ne si te f ie ld n ov i š eh er 15 pa le oc en eeo ce ne irr eg ul ar , v ei nty pe m ag ne si te 15 0, 00 0 10 5, 00 0 a o šv e 16 eo ce ne 40 .5 2. 5 3. 8 15 0, 00 0 65 ,0 00 a a + b c c bi je li kl an ci 17 34 .5 0. 4 3, 00 0 50 0 10 ,0 00 a b b c c sa m ar 18 36 .4 –4 5. 4 0. 2– 13 .5 0. 2– 9. 4 0. 1– 11 .1 6, 50 0 a c b c c ve lik i k riž 19 36 .6 2. 4 20 ,0 00 a b b c c sa č 20 30 .4 2. 2 a c b c c m ur at ov ac 21 45 .6 1. 9 a c b c c ze ni ca -d ob oj ca nt on (f ie ld že pč e) m ag ne si te f ie ld ž ep če 22 pa le oc en e irr eg ul ar , v ei nty pe m ag ne si te 21 .2 –4 5. 0 0. 3– 23 .6 0. 7– 25 .6 0. 5– 6. 4 87 ,0 00 11 9, 00 0 28 2, 00 0 a lo zn ik ov ac 23 32 .9 9 10 .3 76 ,0 00 a b b c c se liš te 24 eo ce ne 34 .1 5. 3 a b b c c ču br in o br do 25 41 .9 1. 6– 19 .7 a a b c c ze ni ca -d ob oj ca nt on (f ie ld ba jv at ) m ag ne si te f ie ld b aj va t 26 irr eg ul ar , v ei nty pe m ag ne si te 29 .0 –5 1. 7 0. 1– 21 .7 1. 3– 40 .2 0. 7– 7. 7 43 ,5 00 22 ,0 00 25 6, 50 0 a /b po lić a nj iv e 27 1. 3– 13 .9 19 1, 00 0 b a b c c ve lik e ra vn i 28 0. 1– 9. 5 b b b c c kr če vi na 29 0. 2– 21 .7 b b b c c ze ni ca -d ob oj ca nt on (f ie ld d iš tic a) m ag ne si te re gi on d iš tic a 30 pa le oc en e irr eg ul ar , v ei nty pe m ag ne si te 39 .5 –4 6. 2 0. 9– 6. 9 1. 6– 4. 6 0. 7– 1. 6 32 ,0 00 b m ao ča 31 7, 00 0 b c b c c d iš tic a 32 7. 0 25 ,0 00 b b b c c ze ni ca -d ob oj ca nt on (f ie ld o lo vo ) m ag ne si te f ie ld o lo vo 33 pa le oc en e irr eg ul ar , v ei nty pe m ag ne si te 45 .1 –4 6. 5 0. 1– 0. 8 1. 1– 3. 0 0. 4– 0. 7 8, 50 0 b d on je l an iš te 34 0. 5 6, 00 0 b c b c c m la do še va c 35 50 0 b c b c c to va rn ic a 36 1, 00 0 b c b c c be rin a 37 1, 00 0 b c b c c g eo lo gi a c ro at ic a geologia croatica 75/2286 r ep ub lic o f sr ps ka (f ie ld ba nj a lu ka -s nj eg ot ina ) m ag ne si te f ie ld b an ja lu ka -s nj eg ot in a 38 ju ra ss ic irr eg ul ar , v ei nty pe m ag ne si te 1, 23 1, 90 0 a je lo va c 39 41 .3 –4 5. 0 1. 2– 4. 1 1. 5– 4. 6 41 9, 99 2 a a + a c c m ed nj ak 40 11 3, 10 0 a a a c pl oč ni 41 44 .5 –4 5. 0 3. 0– 4. 3 1. 3– 1. 7 43 7, 75 7 a a + a c c sn je go tin a 42 42 ,0 50 a b a c c če tn ja 43 16 4, 93 7 a a a c c st an ik ov a 2 44 39 ,5 84 a b a c c ča đa vi ca 2 45 14 ,5 00 a b a c c re pu bl ic o f sr ps ka (f ie ld ba nj a lu ka -v rb an ja ) m ag ne si te f ie ld b an ja lu ka -v rb an ja 46 ju ra ss ic irr eg ul ar , v ei nty pe m ag ne si te 9, 49 7 14 ,5 00 a ja za vi či 1 47 44 .3 1. 4 1. 0 9, 49 7 a c a c c re pi št e 48 45 .7 1. 3 1. 3 14 ,5 00 a b a c c re pu bl ic o f sr ps ka (f ie ld pr nj av or ) m ag ne si te f ie ld p rn ja vo r 49 ju ra ss ic irr eg ul ar , v ei nty pe m ag ne si te 17 6, 92 6 a ra ul ić a po to k 50 45 .1 1. 6 1. 0 39 ,9 26 a b a c c si go va c 51 45 .4 1. 8 2. 3 7, 00 0 a c a c c ta na si ća p ot ok 52 45 .9 1. 4 1. 7 10 ,0 00 a c a c c br ez na 53 40 .1 3. 7 3. 3 43 ,0 00 a b a c c st ra žb en ic a 54 4. 4 4. 2 35 ,0 00 a b a c c ra vn o br do 55 46 .1 1. 4 1. 1 12 ,0 00 a b a c c d om ać ev ac 56 46 .1 0. 4 1. 2 20 ,0 00 a b a c c d ug ov ac 57 46 .4 0. 3 1. 2 10 ,0 00 a c a c c m al a u kr in a 58 18 .3 –3 3. 8 6. 0– 27 .4 0. 4– 26 .4 c c a c c re pu bl ic o f sr ps ka (f ie ld te sl ić ) m ag ne si te f ie ld te sl ić 59 ju ra ss ic irr eg ul ar , v ei nty pe m ag ne si te 88 1, 00 0 a bl at ni ca 60 32 .7 5. 8 7. 1 26 1, 47 5 a a + a c c bu ko vi čk i j ar ak 61 40 .8 5. 6 3. 7 11 9, 99 0 a a a c c m ilo še v ja ra k 62 41 .0 8. 6 1. 5 37 7, 45 6 a a + a c c pr ol et er ov d o 63 42 .6 2. 1 3. 3 69 ,0 65 a b a c c sk ok 64 29 .7 5. 5 14 .1 25 ,0 00 a b a c c vr an ilo vi ći 65 41 .6 3. 8 2. 2 9, 00 0 a c a c c m ak si m ov a ko sa 66 27 .3 18 .5 10 .0 10 ,0 00 a b a c c pa ra dn ja k 67 42 .5 5. 0 1. 6 c c a c c g ov eđ a lu ka 68 29 .2 1. 0 10 ,0 00 a b a c c ta bl e 3. c on tin ue d. g eologia c roatica borojević šoštarić et al.: the geological potential of antimony, bauxite, fluorite, and magnesite of the central dinarides (bosnia and herzegovina) ... 287 ta bl e 4. m ag ne si te d ep os its in b os ni a an d h er ze go vi na (d at a co m pl ie d af te r r ef er en ce s u se d in v er ifi ca tio n an d ev al ua tio n ph as e: č ič ić (1 97 9) ; h o d ži ć et a l., (2 01 4) ; o pe rt a e t a l., (2 01 8) ; m it ro vi ć (2 01 1) ; s u n a ri ćpa m ić e t a l. (1 98 8) ). a re a d ep os it ke y to fi gu re 1 ag e sh ap e m in er al co m m od ity fl ou rs pa r (% ) re se rv es (a +b +c ₁) re se rv es + re so ur se s (a +b +c ₁+ c₂ +d ) q ua nt ity -p er sp ec tiv ity d at a le ve l so ci al li ce nc in g en vi ro nm en ta l m an ag em en t pr oj ec t pe rm itt in g fl ou rs pa r ( t) a ll rm (t ) internal dinarides ce nt ra b os ni a ca nt on m eo vr šj e 1 pa le oz oi ctr ia ss ic ve in , i rr eg ul ar fl uo rs pa r ba -f a /b a /b b c c h rm za 2 a ssb -h gba -f a /b a /b b c c pe ći ne 3 tr ia ss ic fe -m nf 51 4, 00 0 b b b c c re pu bl ic o f sr ps ka ž un elj ub ija 4 pa le oz oi ctr ia ss ic ve in , i rr eg ul ar fl uo rs pa r ba -f 20 1, 50 0 1, 10 0, 00 0 3, 10 0, 00 0 a + a b c c vi dr en ja klj ub ija 5 1, 10 0, 00 0 2, 10 0, 00 0 b b b c c  petrology, geochemistry and tectono-magmatic affinity of gabbroic olistoliths from the ophiolite mélange in the nw dinaric-vardar ophiolite zone (mts. kalnik and ivanščica, north croatia)  †boško lugović1, damir slovenec2, ralf schuster3, winfried h. schwarz4 and marija horvat2 1 university of zagreb, faculty of mining, geology and petroleum engineering, department of mineralogy, petrology and mineral resources, pierottijeva 6, 10000 zagreb, croatia 2 croatian geological survey, sachsova 2, 10000 zagreb, croatia; (corresponding author e-mail: damir.slovenec@hgi-cgs.hr) 3 geological survey of austria, neulinggasse 38, 1030 wienna, austria 4 institute of earth sciences, im neuenheimer feld 234-236, 69120 heidelberg, germany doi: 10.4154/gc.2015.03 ab stra ct mafic intrusive rocks are subordinately represented fragments of the oceanic crust in the ophiolite mélange exposed at mts. kalnik and ivanščica located in the nw dinaric-vardar ophiolite zone. this ophiolite mélange occurs in the northern area of the kalnik unit and represents the sw surface boundary of the zagorje-mid-transdanubian shear zone. the mélange, except for mafic intrusive rocks, consists of a chaotic mixture of various extrusive rocks formed in different tectonic settings of the repno oceanic domain (rod). the rod was the segment of neo-tethys that connects the meliata-maliak and dinaric-vardar oceanic systems. previous study of mafic extrusive sequences suggested an 80 ma period of tectono-magmatic evolution of the rod from intra-continental rifting during the anisian, to the formation of proto-arc crust during the callovian-oxfordian. the domain exposes ophiolitic rocks in four mélange areas. isotropic gabbroic rocks that are abundant in two northern areas (mts. kalnik and ivanščica), can be discriminated into three distinct geochemical groups: (a) n-morb-type gabbro [(th/nb)n = 0.99–1.10; (nb/la)n = 0.95–0.99], (b) iat-type amphibole gabbro with clear supra-subduction characteristics [(th/nb)n = 6.04–8.16; (nb/ la)n = 0.32–0.42] and (c) babb-type amphibole-bearing gabbro [(th/nb)n = 2.88–4.02; (nb/la)n = 0.58–0.69]. representative gabbro samples of each geochemical group were dated by the ar-ar and/or the k-ar dating method. the early jurassic n-morb-type gabbros (geochemical group a), ~185 ma old, signifies a peculiar stage of palaeotethyan slab break-off. the late jurassic iat-type gabbros (geochemical group b), ~147 ma old, is the vestige of a nascent intra-oceanic arc, whilst the early cretaceous babb-type gabbros (geochemical group c), ~100 ma old, provides evidence of magmatism in the back-arc marginal basin. the analyzed gabbroic rocks enable refinement and completion of the geodynamic evolution of the rod, from the opening of an ensialic back-arc basin during the ladinian and a continuous spreading event until the bajocian. intra-oceanic convergence was initiated in the bathonian, with the formation of a nascent island-arc during the tithonian, leading to formation of a cretaceous ensimatic backarc marginal basin. there are many lines of evidence that correlate the geodynamic evolution of the rod with the albanide-hellenide neo-tethyan oceanic segment. keywords: petrology and geochemistry, n-morb, iat, babb, gabbro, ophiolite mélange, dinaric-vardar ophiolite zone, mts. kalnik and ivanščica, croatia geologia croatica 68/1 25–49 13 figs. 6 tabs. zagreb 2015 geologia croaticageologia croatica geologia croatica 68/1geologia croatica 26 1. introduction the oceanic lithosphere may be preserved as large thrust sheets of a relatively undisturbed coherent lithostratigraphic pile (ophiolite complex) thrust onto a tectono-sedimentary unit which represents a chaotic mixture of various (in terms of age and lithology), ophiolitic rock fragments, embedded in a matrix during accretion, obduction and emplacement onto the continental margin (ophiolite mélange). ophiolite mélanges are by consensus understood as chaotic tectono-sedimentary complexes initially deposited by tectonically induced sedimentary processes in the deep ocean trench (accretionary wedge) from a fore-arc region over the subducting plate in front of the leading edge of the overriding plate (festa et al., 2010). consequently, the mélange mostly incorporates very heterogeneous magmatic material, derived from both interfaced oceanic sides of the accretionary wedge, representing remnants of different tectonostratigraphic units formed during the lengthy evolution of an oceanic system. many mélanges are overlain by slices of coherent fragments of the genetically related oceanic lithosphere (ophiolites) which may include lithologies not found in the associated mélange and vice versa (eg.wakabayashi & dilek, 2003). only the systematic petrological and geochemical analyses of ophiolite thrust sheets and magmatic rock fragments archived in the associated mélanges provide the opportunity to study the history of an oceanic system in order to understand the complete geodynamic evolution of an ancient oceanic domain; from intracontinental rifting, onset of oceanization and formation of oceanic lithosphere, through spreading and convergence until the closure and final ophiolite emplacement. such systematic studies are particularly useful when regional field relationships fail in areas of poorly exposed ophiolitic rocks such as the sava zone or the pannonian basin. in the sw segment of the zagorje-mid-transdanubian shear zone (zmtdz), i.e. in the northeasternmost border of the sava-vardar zone (svz) a tectono-sedimentary ophiolite mélange is observed in the form of separate areas outcropping and forming the slopes of mts. kalnik, ivanščica, medvednica & samoborska gora (e.g. pamić & tom lje nović, 1998; with references; fig. 1a). all these mélange areas are integrated as a single tectonostratigraphic unit named by haas et al. (2000) as the kalnik unit (fig. 1b). on account of similar textural features, all the mélange areas of the kalnik unit provide strong evidence for a discrete mesozoic oceanic domain called the repno oceanic domain (rod sensu babić et al., 2002). the rod was a part of the neo-tehtys oceanic realm and links the meliata-maliak and dinaricvardar oceanic domains (babić et al., 2002; fig. 1c). this may be understood to represent the key oceanic domain connecting the central dinaridic ophiolites located to the sw, with meliata-maliak ophiolites to the ne and the alpine ophiolites to the nw (slovenec & lugović 2008, 2009; slovenec et al., 2010, 2011). the rod is documented mainly by isolated bodies of extrusive rocks, whereas coherent fragments of oceanic lithosphere (ophiolite complexes) are lacking. it contains four separate ophiolite mélange areas in two southern (mts. medvednica and samoborska gora), and two northern parts (mts. ivanščica and kalnik) (fig. 1ab). extensive studies of extrusive rocks, particularly the pillow-basalts associated with radiolarian cherts from all four mélange areas (slovenec & lugović, 2009, 2012; slovenec et al., 2010, 2011; kiss et al., 2012), and intrusive gabbroic rocks from the mt. medvednica ophiolite mélange (slovenec & lugović, 2008), provided a highresolution view of the geodynamic evolution of the rod that commenced with intra-continental rifting during anisian time. this was followed by the formation of the proto-oceanic crust, followed by the onset of spreading and maximum widening of the oceanic domain in the bajocian, until the formation of an infant proto-arc crust in the callovian-oxfordian. in many mélange portions, extrusive rock sequences are generally the most abundant fragments. however, subordinate blocks of intrusive gabbroic rocks can also be an excellent magmatic indicator of a geotectonic setting. although the hectometre-scale gabbroic blocks are relatively abundant in the kalnik and ivanščica mts. mélange areas of the rod (fig. 2a-b), they have not been previously investigated in detail. the gabbroic rocks from the kalnik and ivanščica mts. mélange are dated here by ar-ar and/or k-ar dating methods and can be geochemically and petrologically categorized into three distinct groups. therefore, they can represent different geotectonic formational settings that were not recognized in previous research. the aim of this work is to provide an overall petrological and geochemical characterization of the mt. kalnik and ivanščica gabbroic rocks to determine their petrogenesis and to propose a likely geotectonic setting for their formation, with the purpose of improving and completing our knowledge of the geodynamic evolution of the rod as a discrete mesozoic domain that was the corner-stone between the meliata-maliak and dinaric-vardar oceanic systems. the kalnik and ivanščica mts. gabbroic rocks are correlated with equivalent rocks from the nearby mt. medvednica highlighting their potential geotectonic link. with reference to the chronology of particular tectonomagmatic episodes, the inferred geodynamic model for the rod in many respects correlates with the model for the albanide-hellenide neo-tethyan ocean segment, as deduced from the study of ophiolites and ophiolite mélanges in the latter area (saccani et al., 2011). 2. regional geological setting geographically the study area is located in the northernmost part of the dinarides, located between the adriatic sea and the southern alps in the southwest and west and the pannonian basin with some inselbergs in the north and east (fig. 1a-b). the dinarides represent an alpine fold-thrust belt, bordered to the southwest by the adriatic (apulian) microplate, the southalpine and austroalpine unit to the north and by the tisza mega-unit to the east (haas et al., 2000; fig. 1b). they are subdivided into the external dinarides, mainly consisting of mesozoic carbonate platforms (vlahović et al., 2005), and the internal dinarides which comprise several zones: the bosnian flysch zone is overlain by a zone composed of upper jurassic to cretaceous mixed carbonate and siliciclastic sedimentary units, derived from a distal † lugović et al.: petrology, geochemistry and tectono-magmatic affinity of gabbroic olistoliths from the ophiolite mélange in the nw dinaric-vardar ... geologia croatica 27 adriatic plate margin, which was involved in the late jurassic ophiolite obduction. most internal units comprise the central dinaridic ophiolite zone (cdoz) and finally the sava-vardar suture zone (svsz) sensu pamić (2002). the dinarides characteristically stretch northwest-southeast and were traditionally understood to be bracketed between the zagreb-zemplin lineament and the skutari-peć transform fault (eg. pamić, 2002; fig. 1a). figure 1: (a) geotectonic sketch map of the alps, dinarides and hellenides showing the position of the periadriatic-sava-vardar suture zone (after pamić, 2000). legend: 1 – external units (external dinarides and alps); 2 – internal units [passive continental margin, central dinaride ophiolite belt (cdob), mirdita zone]; 3 – periadriatic-sava-vardar zone; 4 – serbo-macedonian massif; 5 – pelagonides; 6 – golija zone; 7 – zagorje-mid-transdanubian zone; 8 – pannonian basin. faults: bl – balaton; df – drava; pl – periadriatic lineament; sf – sava fault; sp – scutari-peć; sn – sava nape; vf – vardar; zz – zagrebzemplin. mountains: i – ivanščica; k – kalnik; ko – kopaonik; kz – kozara; md – medvednica; sg – samoborska gora; sd – szarvaskö-darnó; bü – bükk. b – bódva valley; jk – jaklovce. (b) sketch map of the structural units and major lineaments (modified after haas et al., 2000). insert map: geographic setting of the area presented in the sketch map. legend: bl – balaton lineament; zzl – zagreb-zemplin lineament; pl – periadriatic lineament. (c) sketch map of hypothetical reconstruction of the oceanic belt consisting of meliata, repno and central dinaric ophiolite zone segments (after babić et al., 2002). geologia croatica 68/1geologia croatica 28 the study area comprises the southwestern part of a larger zone, about 100 km wide and 400 km long, sheared between two regional fault systems, the zagreb-zemplin lineament to the south and the periadriatic-balaton lineament to the north, which was (after pamić & tomljenović, 1998), recognized as the zmtdz (fig. 1a-b). this area forms a junction between the southalpine and austroalpine unit, the tisza mega-unit and the internal dinarides. it is also known as the sava unit (haas et al., 2000; fig. 1b). the zmtdz includes triangular shaped intra-pannonian inselbergs: mts. kalnik, ivanščica, medvednica and samoborska gora. the inselbergs are composed of pre-neogene heterogeneous and superimposed dinaric and alpine tectonostratigraphic and tectonometamorphic units, (see for example: pamić & tomljenović, 1998; tari & pamić, 1998; haas et al., 2000; haas & kovács, 2001; pamić, 2002). however, the origin of these units is still debated. structural and palaeomagnetic data indicate that the pre-neogene basement of mts. ivanščica, kalnik and medvednica experienced large, regional-scale tectonic transport from the northwest, and an approximately 130° clockwise rotation during the oligocene to the earliest miocene (tomljenović et al., 2008), that aligned them almost perpendicular to the overall northwest – southeast dinaric structural trend. when reconstructed for this clock-wise rotation, these three mountains continue the main dinaric trend to the northwest. on the basis of their similar tectonostratigraphic evolution, schmid et al. (2008) considered the zmtdz to be part of the western vardar ophiolite unit. the kalnik and ivanščica mts. ophiolite mélange (figs. 2a and b) form the two separate northern mélange areas of the kalnik unit (fig. 1b). the kalnik unit consists of the lithological remnants of a discrete oceanic domain that connects the dinaric-vardar ophiolites, located to the southwest, with the meliata-maliak ophiolites exposed to the northeast. based on matrix palynomorph assemblages, the accretionary age of the kalnik unit, i.e. ophiolite mélange is inferred to be middle jurassic to hauterivian (babić et al., 2002). this time interval represents a period of accumulation of lithostratigraphically diverse material in the intra-oceanic trench (slovenec et al., 2011). the kalnik unit was involved in aptian to post-palaeocene emplacement onto the eastern continental margin of the adria plate (pamić & tomljenović, 1998; pamić, 2002). however, the basement rocks of the kalnik unit in the ivanščica and kalnik mts. are not known. in mt. medvednica, the kalnik unit is thrust onto aptian low-grade metamorphic complexes (medvednica unit, haas et al., 2000; fig. 1b), generated during the emplacement of the late jurassic island-arc onto the adria continental margin (lugović et al., 2006). however, the pelitic to silty matrix of the kalnik unit does not show a metamorphic overprint from burial diagenesis (judik et al., 2008). 3. local geology and description of the study area a simplified geological map of the kalnik and ivanščica mts. is shown in figures 2a and 2b, respectively. the oldest rocks in the area are middle-upper triassic limestones and dolomites derived from the adriatic passive continental margin (šimunić et al., 1982; halamić, 1998). at mt. ivanščica, this carbonate succession is intersected by calcalkaline extrusives and interlayered with distal pyroclastics, interpreted as remnants of a late anisian-ladinian andeantype volcanic arc, located at the european continental margin (goričan et al., 2005). late jurassic to early cretaceous limestones unconformably overlie this middle triassic volcano-sedimentary formation. both units are in turn overthrust onto an ophiolite mélange. these mesozoic rock successions have not been encountered at mt. kalnik. the central ridge of mt. kalnik consists of palaeocene carbonate breccias thrust over neogene sedimentary rocks (šimunić et al., 1981). the common constituents of these breccias are fragments of triassic algal and stromatolitic limestones and dolomites, as well as jurassic and upper cretaceous limestones. similar breccias are also found in nearby mt. medvednica (šimunić et al., 1993), and were encountered during drilling in the drava depression (šimunić & pamić, 1989) suggesting a wide areal extent. several individual fragments of highly serpentinized mantle peridotites (lherzolites) were exhumed at the mountain ridge tectonic zone (poljak, 1942), together with a composite block of serpentinized lherzolite underlain by metamorphic sole amphibolites (lugović et al., 2007). the amphibolites were dated by k-ar on amphibole separates which yielded an age of 118 ± 8 ma (ignjatić, 2007). the northern part of the mt. kalnik ophiolite mélange is thrust onto the neogene-pleistocene sedimentary succession (šimunić et al., 1982). all other contacts of the ophiolite mélange areas of mts. kalnik and ivanščica exhibit a tectonic-erosional unconformity against the youngest neogene and pleistocene sedimentary rocks (fig. 2a-b). the ophiolite mélange areas of mts. kalnik and ivanščica show similar structural features characterized by a “blockin-matrix” fabric, typical of chaotic complexes from subduction-related tectonic mélanges (festa et al., 2010). they are dominated by magmatic rocks and contain lithostratigraphically heterogeneous fragments of sedimentary rocks including greywacke, minor shale, red and grey cherts, and scarce limestones (šimunić et al., 1982). the fragments range in size from pebbles to hectometre-kilometre sized blocks embedded in a predominantly sheared continent-derived pelitic to silty matrix (figs. 2a-b). fragments of mafic extrusive rocks are the prevailing magmatic lithologies in both ophiolite mélange areas. they show various geochemical signatures consistent with their different geotectonic formational settings during an age span from the illyrian to the late oxfordian (slovenec et al., 2011). gabbroic rocks are relatively abundant in the mélange areas of mts. kalnik and ivanščica and occur as hectometre-sized homogeneous blocks (crnković et al., 1974; vrkljan, 1989; pamić, 1997; vrkljan & garašić, 2004; fig. 2a-b). however, an exceptional composite gabbro block, intersected by a metre-wide dacitic dyke was observed in gotalovec quarry at mt. ivanščica. in the field, part of these cretaceous blocks † lugović et al.: petrology, geochemistry and tectono-magmatic affinity of gabbroic olistoliths from the ophiolite mélange in the nw dinaric-vardar ... geologia croatica 29 (fig. 2a, location 3 and fig. 2b, location 3) appear as faultbounded tectonic inclusions subsequently embedded in the mélange during the ophiolite emplacement. the locations of the all analysed blocks are indicated in figure 2a for mt. kalnik and figure 2b for mt. ivanščica. 4. analytical techniques the mineral compositions of ten samples were analysed at the mineralogisches institut der universität heidelberg, germany, using a cameca sx51 electron microprobe equipped with five wavelength-dispersive spectrometers. measurements were performed using an accelerating voltage of 15 kv, a beam current of 20 na, beam size of ~1 µm (for feldspars 10 µm) and 10s counting time for all elements. natural oxides and silicates were used as standards and for calibration. raw data were corrected for matrix effects with the pap algorithm (pouchou & pichoir, 1984, 1985) implemented by cameca. calculations of the structural chemical formulae were undertaken using a software package written by hans-peter meyer (mineralogisches institut, heidelberg). bulk-rock powders for chemical analyses of 21 samples were obtained from vein-free rock chips. the samples were analysed by icp-oes for major elements and icp-ms for figure 2: (a) simplified geological map of mt. kalnik and (b) of mt. ivanščica (modified after šimunić et al., 1982 and halamić, 1998). legend: 1 – neogene and pleistocene sedimentary rocks; 2 – jurassic-cretaceous limestones; 3 – ophiolite mélange with blocks of: 3a basalt, 3b gabbro, 3c tectonite peridotite and triassic-jurassic radiolarites, sandstones and shales (not separated on the maps); 4 – triassic limestones and dolomites; 5 – reverse or thrust faults; 6 – normal faults; 7 – discordance line, tectonic-erosion discordance; 8 – sample location (mt. kalnik: 1 = vsk-242/2, vsk-242/4, vsk-242/6; 2 = vsk204; 3 = vsk-229/1, vsk-229/7, vsk-229/12; 4 = vsk-228, vsk-228/2, vsk-228/5; 5 = vsk-217/1; mt. ivanščica: 1 = be-3; 2 = vsi-5; 3 = vsi-8/1, vsi-8/2; 4 = vsi-7/1; 5 = gi-2, gi-5, gtc-3, gtc-4, gtc-6); 9–picture break; 10 – quarry. geologia croatica 68/1geologia croatica 30 all trace elements, utilizing the 4lithoresearch analytical protocol at activation laboratories in ancaster, canada. major element and trace element concentrations were measured with accuracy better than 1% and 5%, respectively. isotopic compositions of six bulk rock samples were measured in the centre de recherches pétrographiques et géochimiques in vandoeuvre, france on a triton plus mass spectrometer. normalizing ratios of 86sr/88sr = 0.1194 and 146nd/144nd = 0.7219 were used. the 87sr/86sr ratio for the nbs 987 sr standard based on n = 92 for the period of measurement was 0.710242 ± 0.000030 (2σ). the 143nd/144nd ratio for the la jolla standard was 0.511845 ± 0.000010 (2σ) (n = 22). total procedural blanks were ~500 pg and ~ 150 pg for sr and nd, respectively. 40ar/39ar analysis was performed at the institut für geowissenschaften der universität heidelberg, germany. the amphibole separate from the gabbro sample vsk-228 was prepared by crushing and sieving the 200-400 μm fraction followed by magnetic separation and finally by handpicking under a stereomicroscope. for irradiation, the samples were wrapped in al-foil and packed into an evacuated and cdshielded quartz tube. they were irradiated for 15 days with 2*1018 fast neutrons/cm2. the irradiation was performed in the frg-1 reactor of the kernforschungszentrum geesthacht, germany. an apparent age and the flux gradients of the reactor were determined by an in-house muscovite standard; muscovite bmus/2, 328.5 ± 1.1 ma, 1s (schwarz & trieloff, 2007). ar was extracted in a resistance-heated ta furnace in a double-vacuum system up to 1400°c. the gas was cleaned using zr-al getters and a cooling trap. ar isotope compositions were measured in a mat gd-150 gas mass spectrometer with no detectable argon background. constants used for age calculations are those recommended by steiger & jäger (1977) note that suggestions for a revised decay constant for ar-ar dating (renne et al., 2010, 2011; schwarz et al., 2011) would increase the apparent age by 1% in this age range. the argon amounts were corrected for blanks, decay and irradiation interference reactions. 40ar/39ar age uncertainties comprise the errors of the 40ar/39ar ratios of the irradiation monitors and age errors of the monitor. when two age uncertainties are given, the first error is without, while the error in parentheses is with monitor errors. all error assignments of argon isotopic ratios and ages given within this paper are within ± 1σ, unless otherwise stated. the k-ar age data are measured on plagioclase separated from three gabbros (sample vsk-228/5, vsk-229/7 and vsi-8/1). plagioclase was separated by an electromagnetic separator and standard heavy liquid techniques and finally was purified by hand picking under a stereomicroscope. the k concentration and ar analysis were determined by icpoes and an isotope dilution procedure on noble gas mass spectrometry, respectively. the analyses were performed at the activation laboratories in ancaster (canada). the ar analysis: aliquot of the sample is weighted into an al container, loaded into the sample system of the extraction unit, degassed at ~ 100°c over 2 days to remove the surface gases. argon is extracted from the sample in a double vacuum furnace at 1700°c. the argon concentration is determined using isotope dilution with 38ar spike, which is introduced to the sample system prior to each extraction. the extracted gases are cleaned up in a two-step purification system. then pure ar is introduced into the custom built magnetic sector mass spectrometer (reinolds type ) with varian ch5 magnet. the ion source has an axial design (baur-signer source), which provides more than 90% transmission and extremely small isotopic mass-discrimination. measurement of ar isotope ratios is corrected for mass-discrimination and then atmospheric argon is removed, assuming that 36ar is only from the air. the concentration of 40ar radiogenic is calculated using the 38ar spike concentration. after each analysis the extraction temperature is elevated to 1800°c for few minutes and the furnace is prepared for the next analysis. k-analysis: aliquot of the sample is weighted into a graphite crucible with lithium metaborate/tetraborate flux and fussed using a leco induction furnace. the fusion bead is dissolved with acid. standards, blanks and sample are analysed by an icp spectrometer. 5. petrography and mineral chemistry the studied gabbroic rocks are isotropic with preserved igneous fabric and show a non-cumulus anhedral granular texture with grain sizes of 1-3 mm and homogene structure. they were subdivided on the basis of their petrographic characteristics into three groups. the gabbros of group a are composed of plagioclase and augite, the gabbros of group b additionally contain variable edenitic amphibole, whilst edenite represents a minor phase in group c samples (figs. 3a, b, c). ilmenite and apatite occur as accessory minerals in all groups. due to the textural relationships of edenite and its high content of tio2, al2o3 and na2o (up to 2.5, 8.3 and 2.7 wt%, respectively; table 1) it is interpreted as an igneous mineral (compare with coogan, 2003), cotectic with augite (table 2). these amphiboles have slightly different compositions compared to their mt. medvednica analogues which are classified as magnesiohornblende (fig. 4). some of the primary amphibole grains are partly altered to actinolite, ferroactinolite or ferro-anthophyllite (table 1; fig. 4). however, magnesiohornblende in the analysed gabbroic rocks may have formed during late crystallization of an evolved hydrous magma and may reflect the influence of a deep oceanic crustal hydrothermal system. the gotalovec quarry gabbroic rocks (fig. 2b, location 5; which are included in group c based on their geochemical similarities) are characterised by coarse grained intergranular textures and form a texturally unique group. they contain discrete domains of parallel oriented ilmenite plates (up to 35 µm wide) exsolved from completely decomposed mineral. a significant chemical difference with respect to the mn-content of ilmenite was measured between rocks of groups b and c, (7.82-7.96 wt% vs. 3.28-4.67 wt% mno), respectively. the representative gabbro (sample vsk-242/2) from group a contains low-mn ilmenite (< 1.5 wt% mno) typical of ocean ridge gabbros (hébert et al., 1991). plagioclase in gabbro samples of group a shows a nearly homogenous composition (an~50-45). however, magmatic plagioclase preserved † lugović et al.: petrology, geochemistry and tectono-magmatic affinity of gabbroic olistoliths from the ophiolite mélange in the nw dinaric-vardar ... geologia croatica 31 figure 3: microphotography of the kalnik and ivanščica mts. non-cumulus gabbroic rocks subdivided on the basis of petrographic characteristics into three groups: (a) group a – composed of plagioclase and augite (sample vsk-242/2). n+, (b) group b – composed of plagioclase, augite and variable edenitic amphibole (sample vsk-228). n– and (c) group c – composed of plagioclase and augite while edenite represents a minor phase (sample vsk-229/12). n+. legend: pl = plagioclase, cpx = clinopyroxene, amp = amphibole, ilm = ilmenite. in rocks of groups b and c shows continuous normal zoning patterns with the widest core to rim compositional range of an64.3 to an33.7 measured in samples vsk-228 and vsk-228/5 and an56.2 to an36.8 measured in samples vsk-229/7 and vsi8/2. a smaller portion of the measured feldspar shows an albite (an0.3-2.9) to peristerite (an~6) composition. the dacite dyke intersecting gabbroic rocks in the gotalovec quarry (fig. 2b, location 5) shows a dense aphyric finegrained pilotaxitic to intergranular texture. close to the contact with the gabbro it may contain scarce clinopyroxene and albite phenocrysts. clinopyroxene microphenocrysts are only partly replaced or pseudomorphed by ferroedenite/ferrohornblende corresponding to high temperature deuteric alteration, whereas chlorite, pumpellyite and titanite probably reflect hydrothermal alteration. the groundmass consists of albite laths, acicular clinopyroxene, interstitial quartz, ilmenite, chlorite and accessory pumpellyite, zircon, apatite and tourmaline. clinopyroxene composition is repeatedly used as an indicator of petrogenesis and geotectonic setting, particularly in ophiolites and other ocean-related rocks (beccaluva et al., 1989). selected clinopyroxene compositions from the analysed rocks are shown in table 2, plotted in the classification diagram in figure 5, and displayed in geochemical geotectonic discrimination diagrams in figure 6. the clinopyroxene from the gabbroic rocks of all groups is augite (wo36.5-44.7en29.8-47.7fs11.0-29.7). in some samples augite is partly altered to trioctahedral (type “i” of zane & weiss, 1998) chlorite and belongs to the clinochlorechamosite series. in all analysed samples clinopyroxenes show normal zoning patterns with continuously decreasing mg# towards the rim of the crystal, the widest range of 85.4 to 65.7 was measured in the gotalovec quarry sample gtc-4. this type and intensity of zoning is typical for slow cooling in a closed magmatic system (stern, 1979). dacite clinopyroxene has a low-al ferroaugite composition (wo39.7-42.9en16.8-26.9 fs31.4-41.9). both populations show a significant fe-enrichment trend (fig. 5; table 2). the dacite clinopyroxene composition is typical for a highly evolved acidic magma as seen in figure 6 where it occupies a position with the lowest ti and highest na-abundance. geologia croatica 68/1geologia croatica 32 ta bl e 1: s el ec te d m ic ro pr ob e an al ys es a nd fo rm ul ae o f a m ph ib ol e fro m th e ga bb ro ic ro ck s a nd d ac ite in th e ka ln ik (k a) a nd iv an šč ic a (iv ) m ts . o ph io lit e m él an ge . g ro up b g ro up c sa m pl e vs k22 8 vs k22 8 vs k22 8 vs k22 8 vs k22 9/ 1 vs k22 9/ 7 be -3 vs i-5 +g tc -3 +g tc -3 +g tc -3 +g tc -3 +g tc -3 *g tc -6 an al . n r. 1 2 26 27 1 12 13 3 3 17 34 40 57 19 si te c r c r c r c c r c c c c c m in er al ed ed ed ed ed m hb l fa th m hb l fe d fa ct ed fh bl fa th fe d lo ca lit y / s am pl e lo c. ka /4 ka /4 ka /4 ka /4 ka /3 ka /3 iv /1 iv /2 iv /5 iv /5 iv /5 iv /5 iv /5 iv /5 si o 2 43 .8 0 46 .3 0 44 .9 9 47 .4 7 45 .6 8 49 .5 2 49 .2 48 .9 1 48 .1 1 47 .8 1 47 .1 8 47 .5 8 49 .9 7 47 .7 0 ti o 2 3. 01 2. 15 2. 44 1. 73 2. 25 1. 07 0. 62 0. 70 0. 97 1. 09 1. 28 0. 98 0. 72 0. 17 al 2o 3 9. 54 7. 42 8. 28 5. 50 7. 29 3. 26 1. 63 5. 24 3. 20 2. 98 5. 33 3. 32 1. 07 2. 92 cr 2o 3 0. 02 0. 06 0. 04 0. 05 0. 01 0. 10 0. 03 0. 00 0. 00 0. 00 0. 00 0. 03 0. 02 0. 00 fe o 16 .1 2 16 .8 1 17 .4 8 19 .4 7 18 .9 2 20 .9 0 33 .1 9 14 .1 4 26 .3 7 28 .6 5 18 .8 7 28 .9 4 33 .6 8 29 .9 4 m no 0. 34 0. 27 0. 29 0. 05 0. 33 0. 28 0. 37 0. 34 0. 44 0. 46 0. 43 0. 38 0. 56 1. 03 m go 11 .5 6 12 .3 5 11 .4 6 11 .1 0 10 .7 3 10 .2 6 17 .2 9 14 .4 2 8. 23 6. 97 11 .9 5 6. 70 8. 52 5. 08 ca o 10 .2 4 10 .3 1 10 .0 7 9. 98 9. 81 9. 80 4. 17 11 .5 5 8. 54 8. 15 9. 60 8. 00 2. 65 7. 78 n a 2 o 2. 90 2. 24 2. 66 2. 08 2. 53 1. 45 0. 59 0. 89 1. 53 1. 26 2. 04 1. 14 0. 47 1. 87 k 2 o 0. 16 0. 21 0. 19 0. 15 0. 16 0. 30 0. 05 0. 03 0. 35 0. 24 0. 15 0. 25 0. 02 0. 25 h 2o 2. 01 2. 02 2. 01 2. 00 1. 99 1. 98 1. 91 2. 02 1. 94 1. 92 1. 98 1. 91 1. 92 1. 89 to ta l 99 .7 0 10 0. 14 99 .9 1 99 .7 7 99 .7 0 99 .9 8 99 .0 2 98 .2 4 99 .6 8 99 .5 3 98 .8 1 99 .2 0 99 .5 8 98 .6 3 si 6. 61 7 6. 91 4 6. 79 3 7. 18 8 6. 95 1 7. 59 9 7. 76 7 7. 22 1 7. 48 2 7. 50 1 7. 17 3 7. 48 6 7. 81 0 7. 68 6 ti 0. 34 2 0. 24 2 0. 27 7 0. 19 7 0. 25 8 0. 12 4 0. 07 4 0. 07 8 0. 11 3 0. 12 9 0. 14 6 0. 11 6 0. 08 5 0. 02 1 al 1. 69 7 1. 30 5 1. 47 2 0. 98 1 1. 30 6 0. 58 9 0. 30 3 0. 91 2 0. 58 6 0. 55 0 0. 95 4 0. 61 5 0. 19 7 0. 55 5 cr 0. 00 2 0. 00 7 0. 00 5 0. 00 6 0. 00 1 0. 01 2 0. 00 4 0. 00 0 0. 00 0 0. 00 0 0. 00 4 0. 00 4 0. 00 2 0. 00 0 fe 3+ 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 23 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 fe 2+ 2. 03 7 2. 09 9 2. 20 7 0. 46 6 2. 40 8 2. 68 2 4. 38 2 1. 51 6 3. 43 0 3. 75 9 2. 39 9 3. 80 8 4. 40 2 4. 03 5 m n 0. 04 4 0. 03 4 0. 03 7 0. 03 7 0. 04 3 0. 03 6 0. 04 9 0. 04 3 0. 05 8 0. 06 1 0. 05 5 0. 05 1 0. 07 4 0. 14 1 m g 2. 60 4 2. 74 9 2. 58 0 2. 50 6 2. 43 4 2. 34 7 1. 71 6 3. 17 4 1. 90 8 1. 63 0 2. 70 8 1. 57 2 1. 98 5 1. 22 0 ca 1. 65 7 1. 65 0 1. 62 9 1. 61 9 1. 59 9 1. 61 1 0. 70 5 1. 87 2 1. 42 3 1. 37 0 1. 56 4 1. 34 9 0. 44 4 1. 34 3 n a 0. 85 0 0. 64 9 0. 77 9 0. 61 1 0. 74 6 0. 43 1 0. 18 1 0. 25 5 0. 46 1 0. 38 3 0. 60 1 0. 34 8 0. 14 2 0. 58 4 k 0. 03 1 0. 04 0 0. 03 7 0. 02 9 0. 03 1 0. 06 5 0. 01 0 0. 00 6 0. 06 9 0. 04 8 0. 02 9 0. 05 0 0. 00 4 0. 05 1 to ta l 15 .8 81 15 .6 89 15 .8 15 15 .6 40 15 .7 78 15 .4 96 15 .1 91 15 .2 60 15 .5 31 15 .4 31 15 .6 30 15 .3 98 15 .1 46 15 .6 36 m g# 56 .1 56 .7 53 .9 50 .4 50 .3 46 .7 28 .1 64 .5 35 .7 30 .3 53 .0 29 .2 31 .1 23 .2 fo rm ul ae c al cu la te d on th e ba si s o f 2 3 ox yg en s a nd fi xe d nu m be r o f 1 5 ca tio ns e xc lu di ng n a an d k. e st im at ed h 2o c or re sp on ds 2 (o h ) p er fo rm ul ar u ni t. c = co re , r = ri m . e d = ed en ite , f ed = fe rr oed en ite , f hb l = fe rr oho rn bl en de , m hb l = m ag ne si oho rn bl en de , f ac t = fe rr oac tin ol ite , f at h = fe rr oan th op hy lli te . m g# = 1 00 *( m g/ (m g + fe 2+ )). + = d io rit e, * = d ac ite . s am pl e lo ca tio n nu m be r c or re sp on ds to th e lo ca tio ns in f ig ur e 2a -b . † lugović et al.: petrology, geochemistry and tectono-magmatic affinity of gabbroic olistoliths from the ophiolite mélange in the nw dinaric-vardar ... geologia croatica 33 ta bl e 2: s el ec te d m ic ro pr ob e an al ys es a nd fo rm ul ae o f c lin op yr ox en e fro m th e ga bb ro ic ro ck s a nd d ac ite in th e ka ln ik (k a) a nd iv an šč ic a (iv ) m ts . o ph io lit e m él an ge . g ro up a g ro up b g ro up c sa m pl e vs k24 2/ 2 vs k24 2/ 2 vs k22 8 vs k22 8 vs k22 8 vs k21 7/ 1 vs k21 7/ 1 vs k22 9/ 1 vs k22 9/ 1 vs k22 9/ 7 vs k22 9/ 7 be -3 vs i-5 vs i-8 /1 gt c4 gt c4 gt c5 *g tc -6 an al . n r. 2 5 13 14 17 19 20 37 38 14 15 3 19 4 3 4 9 9 si te c c r c c c r c r c r r c c r c c c lo ca lit y / s am pl e lo c. ka /1 ka /1 ka /4 ka /4 ka /4 ka /5 ka /5 ka /3 ka /3 ka /3 ka /3 iv /1 iv /2 iv /3 iv /5 iv /5 iv /5 iv /5 si o 2 50 .7 6 50 .9 2 51 .0 0 51 .9 7 51 .9 8 51 .9 3 51 .3 9 51 .7 5 51 .4 7 50 .9 1 50 .8 4 51 .0 4 50 .6 8 52 .6 7 50 .2 3 50 .1 3 50 .7 3 49 .7 3 ti o 2 1. 13 0. 97 0. 93 0. 79 0. 62 0. 65 0. 67 0. 63 0. 88 0. 86 0. 81 0. 50 0. 80 0. 46 1. 07 1. 01 0. 32 0. 19 al 2o 3 2. 91 2. 95 2. 77 2. 76 2. 84 2. 15 1. 55 2. 74 2. 26 3. 13 2. 31 1. 38 1. 88 1. 22 2. 86 3. 25 0. 64 0. 42 cr 2o 3 0. 01 0. 00 0. 04 0. 03 0. 31 0. 07 0. 00 0. 62 0. 00 0. 08 0. 00 0. 00 0. 00 0. 06 0. 04 0. 06 0. 03 0. 00 fe o 12 .1 9 10 .6 3 9. 76 8. 20 6. 87 8. 43 11 .6 7 7. 28 10 .9 2 8. 04 11 .4 4 15 .4 5 11 .1 9 11 .5 5 9. 69 7. 98 19 .0 1 22 .7 8 m no 0. 34 0. 28 0. 28 0. 25 0. 22 0. 27 0. 38 0. 29 0. 43 0. 23 0. 37 0. 57 0. 33 0. 34 0. 23 0. 12 0. 63 0. 71 m go 15 .0 3 15 .7 8 14 .5 8 15 .3 6 15 .9 4 15 .8 3 14 .4 4 15 .2 5 13 .5 6 15 .4 5 13 .7 5 11 .6 8 13 .7 8 13 .8 4 14 .0 0 14 .4 8 8. 75 6. 21 ca o 17 .2 9 17 .7 3 19 .5 4 20 .3 0 20 .6 8 19 .9 7 18 .5 3 20 .9 4 20 .0 3 20 .3 3 19 .6 6 18 .1 3 19 .7 4 19 .7 3 20 .9 6 21 .3 8 19 .4 0 18 .9 6 n a 2 o 0. 30 0. 30 0. 40 0. 31 0. 30 0. 28 0. 25 0. 25 0. 31 0. 38 0. 29 0. 24 0. 24 0. 30 0. 30 0. 32 0. 25 0. 31 to ta l 99 .9 5 99 .5 6 99 .3 0 99 .9 7 99 .7 6 99 .5 8 98 .8 8 99 .7 5 99 .8 6 99 .4 1 99 .4 7 98 .9 9 98 .6 4 99 .4 2 99 .3 8 98 .7 3 99 .7 6 99 .3 1 si 1. 89 7 1. 89 7 1. 90 9 1. 92 2 1. 91 7 1. 92 6 1. 94 5 1. 91 7 1. 93 2 1. 88 9 1. 91 5 1. 96 8 1. 92 5 1. 95 8 1. 88 4 1. 88 0 1. 98 0 1. 98 5 ti 0. 03 2 0. 02 7 0. 02 6 0. 02 2 0. 01 7 0. 01 8 0. 01 9 0. 01 8 0. 02 5 0. 02 4 0. 02 5 0. 01 5 0. 02 3 0. 01 3 0. 03 0 0. 02 8 0. 00 9 0. 00 6 al iv 0. 10 3 0. 10 3 0. 09 1 0. 07 8 0. 08 3 0. 07 4 0. 05 5 0. 08 3 0. 06 8 0. 11 1 0. 08 5 0. 03 2 0. 07 5 0. 04 2 0. 11 6 0. 12 0 0. 02 0 0. 01 5 al vi 0. 02 5 0. 02 7 0. 03 2 0. 04 2 0. 04 0 0. 02 0 0. 01 4 0. 03 7 0. 03 2 0. 02 6 0. 01 8 0. 03 1 0. 00 9 0. 01 3 0. 01 0 0. 02 4 0. 00 9 0. 00 5 cr 0. 00 0 0. 00 0 0. 00 1 0. 00 1 0. 00 9 0. 00 2 0. 00 0 0. 01 8 0. 00 0 0. 00 2 0. 00 0 0. 00 0 0. 00 0 0. 00 2 0. 00 1 0. 00 2 0. 00 1 0. 00 0 fe 3+ 0. 03 7 0. 04 3 0. 03 4 0. 01 3 0. 02 1 0. 03 6 0. 02 0 0. 01 1 0. 00 9 0. 06 3 0. 04 2 0. 00 3 0. 03 7 0. 02 3 0. 06 5 0. 06 0 0. 01 0 0. 02 2 fe 2+ 0. 34 4 0. 28 9 0. 27 1 0. 24 1 0. 19 2 0. 22 6 0. 34 9 0. 21 5 0. 33 4 0. 18 7 0. 31 8 0. 49 6 0. 31 8 0. 34 1 0. 23 9 0. 19 0 0. 61 0 0. 73 9 m n 0. 01 1 0. 00 9 0. 00 9 0. 00 8 0. 00 7 0. 00 8 0. 01 2 0. 00 9 0. 01 4 0. 00 7 0. 01 0 0. 01 9 0. 01 1 0. 01 1 0. 00 7 0. 00 4 0. 02 1 0. 02 4 m g 0. 83 7 0. 87 7 0. 81 4 0. 84 7 0. 87 6 0. 87 5 0. 81 5 0. 84 2 0. 75 9 0. 85 5 0. 77 2 0. 67 1 0. 78 0 0. 77 8 0. 78 3 0. 81 0 0. 50 9 0. 37 0 ca 0. 69 2 0. 70 8 0. 78 4 0. 80 4 0. 81 7 0. 79 4 0. 75 2 0. 83 1 0. 80 6 0. 80 8 0. 79 4 0. 74 9 0. 80 3 0. 79 7 0. 84 2 0. 85 9 0. 81 1 0. 81 1 n a 0. 02 2 0. 02 2 0. 02 9 0. 02 2 0. 02 1 0. 02 0 0. 01 8 0. 01 8 0. 02 3 0. 02 7 0. 02 1 0. 01 8 0. 01 8 0. 02 2 0. 02 2 0. 02 3 0. 01 9 0. 02 4 m g# 70 .9 75 .2 75 .0 77 .9 82 .0 2 79 .5 70 .0 79 .7 69 .4 82 .1 70 .8 75 .7 71 .0 69 .5 76 .6 81 .0 45 .5 33 .4 al vi /a liv 0. 24 0. 26 0. 36 0. 54 0. 48 0. 27 0. 25 0. 46 0. 45 0. 23 0. 21 0. 97 0. 12 0. 31 0. 09 0. 20 0. 45 0. 33 w o 36 .0 36 .8 41 .0 42 .1 42 .7 40 .9 38 .6 43 .6 41 .9 42 .1 40 .9 38 .7 41 .2 41 .3 43 .5 44 .7 41 .4 41 .3 en 43 .6 45 .6 42 .6 44 .3 45 .8 45 .2 41 .8 44 .1 39 .5 44 .5 39 .8 34 .7 40 .0 47 .7 40 .4 42 .1 25 .9 18 .8 fs 20 .4 17 .7 16 .5 13 .7 11 .4 13 .9 19 .6 12 .3 18 .6 13 .4 19 .2 26 .7 18 .8 11 .0 16 .1 13 .2 32 .7 39 .9 fo rm ul ae c al cu la te d on th e ba si s o f 4 c at io ns a nd 6 o xy ge ns . c = c or e, r = rim . m g# = 1 00 *( m g/ (m g + fe 2+ )). * = d ac ite . s am pl e lo ca tio n nu m be r c or re sp on ds to th e lo ca tio ns in f ig ur e 2a -b . geologia croatica 68/1geologia croatica 34 figure 4: aliv – (na + k)a plot of amphiboles from the kalnik and ivanščica mts. gabbroic rocks with the nomenclature fields of leake et al. (1997). fields of amphiboles from the mt. medvednica middleto late jurassic gabbros and ultramafic cumulates (lugović et al., 2007; slovenec & lugović, 2008) are shown for comparison. figure 5: plot of clinopyroxene compositions in the en – wo – fs (mg2si2o6 – ca2si2o6 – fe2si2o6) diagram with the nomenclature fields of morimoto (1988) for gabbroic rocks and dacite from the kalnik and ivanščica mts. ophiolite mélange. field for clinopyroxene compositions from middleto late jurassic isotropic gabbros in the mt. medvednica ophiolite mélange (slovenec & lugović, 2008) are plotted for correlation constraints. clinopyroxenes from the gabbroic group a, show the lowest woand higher fs-content (fig. 5) and have significantly higher ti-abundance than clinopyroxene populations hosted in the gabbroic rocks of groups b and c (fig. 6; table 2). the clinopyroxenes from group b show compositions similar to clinopyroxenes hosted in amphibole gabbros from nearby mt. medvednica (fig. 5) that are related to late middle jurassic intra-oceanic subduction in the rod (slovenec & lugović, 2008). in the same figure, the clinopyroxene populations from group a show a wide span of fs-content and overlap with clinopyroxene compositions from rocks of group c. 6. bulk rock chemical composition table 3 displays the results of 20 analyses of gabbroic rocks and 1 dacite from the ivanščica and kalnik mts. tectonosedimentary ophiolite mélange. nd and sr isotopic composition of 6 gabbroic samples are shown in table 4. the analysed gabbroic rocks were subdivided on the basis of geochemical criteria into three geochemical groups (see section 6 below) which were isotopically dated to three distinct geological times (see section 7 below). the geochemical group a is represented by the early jurassic sample vsk-242/2 (fig. 2a, location 1), group b by the late jurassic samples vsk-228 and 228/5 (fig. 2a, location 4) and geochemical group c by early cretaceous samples vsk-229/7 (fig. 2a, location 3) and sample vsi-8/1 (fig. 2b, location 3). the analysed gabbroic rocks partly underwent deuteric and sea-floor hydrothermal alteration which resulted in a minor increase in the loss on ignition (loi £ 3.08 wt%) and minor chemical modification of the major elements. in addition, the tio2 vs. al2o3 diagram (colombi, 1989) clearly shows that all analysed gabbros reflect basaltic liquid composition (fig. 7a). this indicates that our gabbroic rocks may be considered to reflect original magmatic composition. † lugović et al.: petrology, geochemistry and tectono-magmatic affinity of gabbroic olistoliths from the ophiolite mélange in the nw dinaric-vardar ... geologia croatica 35 figure 6: (a) ti – aliv and (b) sio2/100 – na2o – tio2 discriminant diagram (simplified after beccaluva et al., 1989) for clinopyroxene from gabbroic rocks and dacite of the kalnik and ivanščica mts. ophiolite mélange. iat = island-arc tholeiites, morb = mid-ocean ridge basalts, babb = back-arc basin basalts. fields for clinopyroxene compositions from middleto late jurassic isotropic gabbros in the mt. medvednica ophiolite mélange (slovenec & lugović, 2008) are plotted for correlation constraints. figure 7: (a) al2o3 – tio2 discrimination diagram (adopted from colombi, 1989) and (b) tas classification diagram with the nomenclature fields of intrusive rocks after cox et al. (1979) for the gabbroic rocks from the kalnik and ivanščica mts. ophiolite mélange. in the (na2o + k2o) vs. sio2 classification diagram for intrusive rocks (cox et al., 1979), all rocks plot in the subalkaline field (fig. 7b). the majority of the mafic samples plot in the gabbro field and only sample gtc-3 from gotalovec quarry represents a true diorite composition, pointing to the relative immobility of na and k. in the same type of diagram for volcanic rocks, the felsic dyke (sample gtc-6) intersecting the gotalovec quarry intrusives, plots in the dacite field (not shown). samples from gotalovec quarry represent the fractionated rocks, whereby sample gtc-4 is the least fractionated specimen. on the basis of co-variation of tio2 and mg# following the classification scheme for ophiolitic gabgeologia croatica 68/1geologia croatica 36 ta bl e 3: c he m ic al a na ly se s o f g ab br oi c ro ck s a nd d ac ite in th e ka ln ik (k a) a nd iv an šč ic a (iv ) m ts . o ph io lit e m él an ge . g ro up a g ro up b g ro up c sa m pl e vs k24 2/ 2 vs k24 2/ 4 vs k24 2/ 6 vs k20 4 vs k22 8 vs k22 8/ 2 vs k22 8/ 5 vs k21 7/ 1 vs k22 9/ 1 vs k22 9/ 7 vs k22 9/ 12 be -3 vs i-5 vs i-7 /1 vs i-8 /1 vs i-8 /2 gi -2 gi -5 +g tc -3 gt c4 *g tc -6 lo ca lit y / sa m pl e lo c. ka /1 ka /1 ka /1 ka /2 ka /4 ka /4 ka /4 ka /5 ka /3 ka /3 ka /3 iv /1 iv /2 iv /4 iv /3 iv /3 iv /5 iv /5 iv /5 iv /5 iv /5 si o 2 49 .1 0 48 .5 3 49 .8 4 51 .9 1 50 .4 9 49 .9 9 49 .4 2 49 .6 5 49 .0 3 49 .7 6 49 .2 2 50 .9 9 50 .8 5 48 .9 3 49 .4 8 49 .6 7 51 .4 5 51 .2 6 55 .9 9 50 .7 0 64 .5 8 ti o 2 2. 06 2. 25 2. 14 1. 03 0. 97 0. 99 0. 91 1. 35 1. 66 1. 74 1. 50 2. 13 2. 29 2. 19 1. 36 1. 35 1. 64 1. 55 2. 04 1. 74 0. 51 al 2o 3 14 .6 8 14 .2 8 14 .3 0 13 .0 1 15 .0 1 15 .0 5 15 .9 5 14 .1 0 14 .3 7 14 .2 1 14 .3 2 14 .6 2 12 .6 3 11 .8 9 13 .2 7 13 .3 3 15 .9 0 16 .9 6 14 .6 1 16 .4 9 16 .1 3 fe 2o 3t ot al 10 .0 2 10 .5 4 10 .5 3 9. 84 9. 81 8. 58 9. 12 8. 89 10 .2 4 10 .3 0 9. 69 9. 81 12 .4 2 14 .0 5 10 .2 7 9. 92 10 .1 6 9. 14 10 .7 8 10 .0 8 6. 38 m no 0. 67 0. 17 0. 19 0. 18 0. 33 0. 25 0. 29 0. 17 0. 19 0. 20 0. 17 0. 24 0. 25 0. 27 0. 18 0. 18 0. 17 0. 17 0. 23 0. 19 0. 13 m go 5. 75 6. 45 6. 93 8. 30 9. 99 9. 76 9. 37 7. 61 8. 33 8. 36 7. 84 6. 25 6. 37 8. 19 9. 14 9. 50 5. 99 5. 52 3. 42 5. 73 0. 84 ca o 10 .4 4 10 .0 6 9. 09 7. 97 6. 70 8. 02 8. 32 10 .1 5 8. 62 6. 95 9. 10 7. 72 6. 52 6. 83 7. 85 8. 61 6. 45 6. 62 4. 47 7. 21 1. 74 n a 2 o 3. 28 3. 78 3. 72 4. 46 3. 90 3. 15 3. 43 4. 30 3. 97 4. 31 3. 93 4. 01 4. 75 4. 26 4. 11 3. 76 5. 30 5. 52 5. 04 5. 37 8. 49 k 2 o 0. 04 0. 08 0. 05 0. 73 0. 49 0. 19 0. 47 0. 03 0. 18 0. 80 0. 37 0. 19 0. 16 0. 08 0. 24 0. 01 0. 07 0. 01 0. 47 0. 02 0. 23 p 2 o 5 0. 22 0. 23 0. 20 0. 10 0. 08 0. 09 0. 07 0. 17 0. 16 0. 18 0. 15 0. 28 0. 21 0. 23 0. 15 0. 12 0. 18 0. 23 0. 36 0. 17 0. 10 lo i 3. 05 2. 95 3. 05 2. 31 2. 62 3. 03 2. 26 3. 08 3. 06 2. 75 2. 93 3. 05 3. 04 2. 07 3. 01 3. 03 2. 99 2. 92 3. 04 0. 24 1. 61 to ta l 99 .3 1 10 0. 32 10 0. 04 99 .8 4 10 0. 39 99 .1 0 99 .6 1 99 .5 0 99 .8 1 99 .8 4 99 .2 2 99 .2 9 99 .4 9 99 .9 9 99 .0 6 99 .4 8 10 0. 30 99 .9 0 10 0. 45 10 0. 90 10 0. 74 m g# 53 .2 4 56 .0 8 57 .8 4 64 .9 0 68 .9 9 71 .3 0 67 .6 1 62 .9 0 62 .2 5 62 .3 4 63 .5 9 58 .2 0 50 .7 9 54 .8 8 64 .4 1 67 .9 1 54 .2 5 55 .1 5 40 .3 8 56 .0 7 23 .0 4 cs 0. 2 0. 1 0. 1 2. 9 1. 2 1. 4 0. 8 1. 0 2. 6 3. 8 2. 3 1. 6 1. 0 0. 2 0. 3 0. 6 2. 0 0. 2 1. 2 1. 3 0. 8 rb 1 1 2 10 15 8 16 1 8 7 11 8 13 3 2 3 1 1 11 1 5 ba 54 79 67 33 0 31 4 20 8 35 5 78 16 4 34 1 17 2 60 8 65 7 74 18 8 17 4 11 4 75 23 7 47 12 5 th 0. 50 0. 32 0. 28 0. 28 0. 25 0. 29 0. 21 0. 43 0. 43 0. 50 0. 43 1. 27 0. 92 0. 78 0. 42 0. 35 0. 44 0. 56 1. 28 0. 43 1. 81 ta 0. 31 0. 36 0. 34 0. 05 0. 04 0. 04 0. 03 0. 14 0. 17 0. 19 0. 16 0. 38 0. 33 0. 25 0. 13 0. 12 0. 15 0. 22 0. 43 0. 18 0. 47 n b 4. 9 5. 8 5. 3 0. 9 0. 7 0. 7 0. 5 2. 3 2. 8 3. 1 2. 6 6. 1 5. 5 4. 1 2. 1 2. 0 2. 5 3. 6 6. 9 2. 9 7. 6 sr 89 72 11 5 28 9 23 3 13 5 20 2 17 5 30 3 34 0 26 4 18 7 24 6 91 16 6 15 7 14 1 87 21 0 78 13 8 zr 11 7 12 9 12 4 70 57 63 49 11 1 11 3 12 9 11 6 18 7 18 0 16 5 93 85 87 12 3 22 4 10 3 35 0 h f 3. 4 3. 8 3. 6 2. 0 1. 7 1. 8 1. 4 2. 8 3. 1 3. 8 3. 0 5. 9 5. 5 4. 8 2. 7 2. 4 2. 6 3. 6 6. 9 3. 1 9. 1 y 39 .7 42 .5 43 .1 27 .6 25 .0 27 .2 21 .8 34 .2 33 .4 35 .8 33 .7 58 .7 58 .5 51 .4 32 .4 29 .8 30 .3 45 75 .9 35 .4 90 .7 sc 41 40 37 42 38 36 36 37 40 37 38 27 37 38 40 42 35 28 22 35 11 v 33 3 38 0 34 6 34 4 33 8 35 7 32 1 28 9 31 8 31 8 30 0 32 8 41 1 37 5 27 9 27 9 31 9 28 5 32 2 30 5 27 3 cr 11 0 12 5 13 0 23 0 26 0 25 2 24 4 20 0 29 0 25 0 16 0 19 19 20 40 0 45 0 40 30 18 34 20 n i 40 39 41 40 <2 0 <2 0 <2 0 <2 0 <2 0 <2 0 <2 0 <2 0 <2 0 <2 0 60 40 40 30 30 31 <2 0 la 5. 97 6. 57 6. 25 2. 31 1. 81 2. 06 1. 69 3. 98 4. 58 5. 33 4. 37 9. 43 8. 62 7. 59 3. 76 3. 40 3. 95 5. 66 12 .1 0 4. 77 15 .0 0 ce 16 .7 9 18 .6 4 17 .8 5 7. 28 5. 55 6. 25 5. 01 12 .6 0 13 .7 3 15 .8 0 13 .1 1 28 .7 1 24 .9 3 22 .0 1 11 .7 0 10 .4 0 12 .3 16 .8 0 34 .3 13 .7 0 44 .3 0 pr 2. 71 2. 92 2. 80 1. 30 1. 07 1. 27 0. 86 1. 97 2. 14 2. 45 2. 06 4. 29 3. 82 3. 36 1. 83 1. 68 1. 92 2. 59 5. 36 2. 24 6. 53 n d 14 .1 0 15 .1 4 14 .7 0 7. 07 6. 41 6. 34 5. 16 11 .1 0 11 .8 5 13 .3 0 11 .4 0 22 .3 0 20 .2 0 18 .0 0 10 .3 0 9. 38 10 .3 0 14 .1 0 27 .4 0 11 .8 0 32 .3 0 sm 4. 74 5. 18 4. 94 2. 63 2. 34 2. 59 2. 16 3. 38 3. 65 4. 33 3. 53 6. 53 5. 95 5. 32 3. 23 2. 90 3. 29 4. 34 8. 58 3. 67 9. 91 eu 1. 55 1. 86 1. 71 0. 93 0. 81 0. 97 0. 65 1. 25 1. 45 1. 50 1. 34 2. 28 2. 25 1. 86 1. 17 1. 12 1. 36 1. 60 2. 77 1. 44 3. 11 g d 6. 05 6. 59 6. 45 3. 57 3. 27 3. 68 3. 09 4. 70 5. 11 5. 46 4. 90 8. 32 8. 07 7. 24 4. 49 4. 11 4. 45 5. 95 10 .9 0 5. 09 12 .0 0 tb 1. 17 1. 29 1. 21 0. 63 0. 58 0. 65 0. 52 0. 86 0. 94 1. 00 0. 89 1. 56 1. 51 1. 31 0. 84 0. 74 0. 85 1. 12 2. 08 0. 98 2. 44 d y 7. 12 7. 58 7. 42 4. 04 3. 83 4. 36 3. 34 5. 49 5. 97 6. 37 5. 69 10 .4 0 9. 77 8. 53 5. 49 4. 91 5. 45 7. 10 12 .9 0 6. 20 15 .2 0 h o 1. 56 1. 71 1. 61 0. 87 0. 84 1. 01 0. 74 1. 19 1. 30 1. 38 1. 23 2. 29 2. 11 1. 83 1. 18 1. 06 1. 09 1. 43 2. 75 1. 33 3. 36 er 4. 59 4. 81 4. 09 2. 78 2. 69 2. 85 2. 37 3. 63 3. 95 4. 23 3. 69 6. 99 6. 40 5. 60 3. 58 3. 24 3. 27 4. 31 8. 03 3. 82 10 .1 0 tm 0. 67 2 0. 70 1 0. 68 3 0. 43 3 0. 39 6 0. 44 5 0. 35 3 0. 51 4 0. 55 8 0. 59 8 0. 52 5 1. 00 1 0. 90 5 0. 79 6 0. 50 4 0. 44 8 0. 47 8 0. 62 6 1. 19 1 0. 55 7 1. 61 0 yb 4. 48 4. 74 4. 54 3. 08 2. 92 3. 11 2. 37 3. 31 3. 51 3. 84 3. 42 6. 46 5. 90 5. 20 3. 18 2. 92 3. 13 4. 13 7. 71 3. 62 10 .1 0 lu 0. 68 2 0. 71 8 0. 70 1 0. 44 2 0. 40 2 0. 45 5 0. 33 4 0. 48 3 0. 50 9 0. 57 0 0. 49 3 0. 92 6 0. 88 4 0. 76 0 0. 46 8 0. 43 0 0. 46 3 0. 63 2 1. 25 0 0. 57 3 1. 62 0 m aj or e le m en ts in w t.% , t ra ce e le m en ts in p pm . l o i = lo ss o n ig ni tio n at 1 10 0o c. m g# = 1 00 *m ol ar (m go /( m go +f eo to ta l)) . + = d io rit e, * = d ac ite . s am pl e lo ca tio n nu m be r c or re sp on ds to th e lo ca tio ns in f ig ur e 2a -b . † lugović et al.: petrology, geochemistry and tectono-magmatic affinity of gabbroic olistoliths from the ophiolite mélange in the nw dinaric-vardar ... geologia croatica 37 ta bl e 4: n d an d sr is ot op ic d at a of g ab br os fr om th e ka ln ik (k a) a nd iv an šč ic a (iv ) m ts . o ph io lit e m él an ge . sa m pl e l oc al ity / g ro up 14 7 sm /14 4 n d 14 3 n d/ 14 4 n da 87 rb /86 sr a 87 sr /86 sr a s m n d r b s r e n d( t)b 87 sr /86 sr (t) c a ge (t )* s am pl e lo c. vs k24 2/ 2 ka /1 a 0. 20 32 5 0. 51 29 23 ( 9 ) 0. 03 25 06 0. 70 32 08 (1 0) 4. 74 14 .1 0 1 89 +5 .4 1 0. 70 31 22 18 5 m a vs k22 8 ka /4 b 0. 22 07 2 0. 51 29 42 ( 8 ) 0. 15 89 75 0. 70 43 16 ( 9) 2. 34 6. 41 15 27 3 +5 .4 7 0. 70 39 77 14 7 m a vs k22 9/ 7 ka /3 c 0. 19 68 4 0. 51 29 23 ( 7 ) 0. 05 95 65 0. 70 37 62 ( 5) 4. 33 13 .3 0 7 34 0 +5 .5 6 0. 70 36 73 10 5 m a vs k22 9/ 12 ka /3 c 0. 19 54 9 0. 51 29 55 ( 3 ) 0. 12 05 51 0. 70 38 58 ( 4) 3. 88 12 .0 0 11 26 4 +6 .2 0 0. 70 36 87 10 5 m a gi -2 iv /5 c 0. 19 31 3 0. 51 29 64 (1 5) 0. 02 05 18 0. 70 34 33 (1 4) 3. 29 10 .3 0 1 14 1 +6 .4 3 0. 70 34 04 10 5 m a vs i-8 /1 iv /2 c 0. 18 96 0 0. 51 29 50 (1 2) 0. 03 48 57 0. 70 35 64 (1 3) 3. 23 10 .3 0 2 16 6 +6 .2 3 0. 70 35 14 10 5 m a sa m pl e lo ca tio n nu m be r c or re sp on ds to th e lo ca tio ns in f ig ur e 2a -b . a er ro rs in b ra ck et s f or n d an d sr is ot op ic ra tio s a re g iv en a t t he 2 sle ve l. t he 14 7 sm /14 4 n d ra tio s c al cu la te d fro m s m a nd n d ic pm s co nc en tr at io ns (d is pl ay ed in pp m ) f ol lo w in g th e eq ua tio n: 14 7 sm /14 4 n d = (s m /n d) * [0 .5 31 51 + 0 .1 42 52 * 14 3 sm /14 4 n d] . t he 87 rb /86 sr ra tio s c al cu la te d fro m r b an d sr ic pm s co nc en tr at io ns (d is pl ay ed in p pm ) f ol lo w in g th e eq ua tio n: 87 rb /86 sr = (r b/ sr ) * [2 .6 93 9 + 0. 28 32 * 87 sr /86 sr ]. b in iti al e n d( t) ca lc ul at ed a ss um in g io ch u r = 0 .5 12 63 8, (14 7 sm /14 4 n d) o ch u r = 0 .1 96 6, a nd l sm = 6 .5 4 * 10 -1 2 a -1 . c in iti al 87 sr /86 sr (t) c al cu la te d as su m in g l r b = 1 .4 2 * 10 -1 1 a -1 . * co re sp on di ng a rb itr ar y ag e fo r t he in iti al e n d an d in iti al s r i so to pi c ra tio s. ta bl e 5: k –a r a ge s o f g ab br oi c ro ck s i n th e ka ln ik (k a) a nd iv an šč ic a (iv ) m ts . o ph io lit e m él an ge . sa m pl e lo ca lit y/ g ro up an al is ed k [% ] 40 ar (r ad ) 40 ar (a ir) ag e sa m pl e lo c. m at er ia l nl /g [% ] m a ± 1s vs k22 8/ 5 ka /4 b pl ag io cl as e 0. 39 5 1. 11 6 55 .6 0 14 6. 4 ± 3. 4 vs k22 9/ 7 ka /3 c pl ag io cl as e 0. 70 9 3. 06 7 68 .4 1 10 7. 6 ± 4. 2 vs i-8 /1 iv /2 c pl ag io cl as e 0. 12 9 4. 50 1 41 .5 0 10 3. 4 ± 3. 6 sa m pl e lo ca tio n nu m be r c or re sp on ds to th e lo ca tio ns in f ig ur e 2a -b . ta bl e 6: 40 ar /39 ar d at a of a m ph ib ol e fro m g ab br o sa m pl e vs k22 8 (g eo ch em ic al g ro up b ) f ro m th e m t. ka ln ik o ph io lit e m él an ge . st ep t em p. t im e 40 ar */ 39 ar 38 ar /39 ar 37 ar /39 ar 36 ar /39 ar cu m . r ad . a pp ar en t a ge x 1 0–2 39 ar 40 ar ± 1 s s.d . ( o c) ( m in .) (% ) (% ) ( m a) 1 60 0 10 5 ± 18 .0 0. 68 ± 0 .0 9 19 .9 ± 1 .7 0 25 2 ± 23 1. 59 0. 67 58 ± 2 04 2 70 0 10 30 ± 6 .0 0. 41 ± 0 .0 7 12 .2 ± 0 .5 0 18 8 ± 8 4. 48 5. 50 31 6 ± 65 3 80 0 10 –1 0 ± 17 .0 0. 42 ± 0 .0 3 50 .7 ± 2 .4 0 20 9 ± 10 3. 25 –1 .6 7 –1 25 ± 2 12 4 88 0 10 13 .3 ± 4 .5 0. 14 ± 0 .0 5 15 .9 ± 0 .4 0 37 ± 2 6. 45 9. 17 14 6 ± 18 5 96 0 10 8. 8 ± 4. 2 0. 08 ± 0 .0 2 11 .4 4 ± 0. 30 5 ± 1 10 .4 8 19 .2 2 98 ± 1 5 6 10 40 10 14 .0 ± 2 .0 0. 15 ± 0 .1 1 17 .2 7 ± 0. 35 2 ± 1 18 .5 8 37 .6 9 15 3 ± 11 7 11 20 10 14 .4 ± 0 .9 0. 31 ± 0 .0 1 30 .3 ± 0 .6 0 3 ± 1 35 .9 1 37 .7 6 15 7 ± 9 8 12 00 10 22 .4 ± 1 .2 0. 21 ± 0 .0 1 30 .1 ± 0 .6 0 23 ± 1 19 .2 6 17 .4 4 23 9 ± 12 m as s d is cr im in at io n (m ea su re d 40 ar /36 ar = 2 79 .9 ± 0 .2 ), ar go n is ot op ic a bu nd an ce s c or re ct ed fo r l in e an d fu rn ac e bl an k an d nu cl og en ic in te rf er en ce s 40 ar /39 ar k = 0 .0 15 ± 0 .0 04 ; 38 ar /39 ar k = 0 .0 18 ± 0 .0 02 ; 36 ar /37 ar ca = 0 .0 00 43 ± 0. 00 00 2; 39 ar /37 ar ca = 0 .0 00 98 ± 0 .0 00 03 ). jfa ct or = 0 .0 06 32 1 ± 0. 00 00 61 (± 0 .0 00 06 5) (b m us /2 : t = 3 28 .5 ± 1 .1 m a, s ch w a rz & t ri el o ff , 2 00 7) . geologia croatica 68/1geologia croatica 38 broic rocks (serri, 1981), the analysed samples of groups a and c correspond to a high-ti gabbro (typical for a morb/ babb setting) and samples of group b match to the low-ti suite (typical for a ssz setting). successive alteration may also mobilize trace elements that are very important indicators of petrogenetic processes and for the geotectonic formational setting of the rock. a test of trace element mobility in our samples was applied by plotting their concentration against zr (not shown). high-field strength elements ti, p, ta, nb, y and th (hfse) as well as all rare earth elements (ree) appeared to be relatively immobile during alteration. in contrast, almost all large ion lithophile elements (lile) showed selective, but generally high intensities of mobility and consequently will not be utilized for petrogenetic and geotectonic constraints. on multielement abundance patterns normalized to n-type morb, the analysed gabbros reveal a broad variety of compositions (fig. 8a,b), suggesting different sources and/or fractional spans. neglecting the lile, which are selectively enriched due to alterations, the relative concentration profile is characterized by smooth patterns at 0.6 to 9.8 times relative to n-morb. however, all samples of geochemical groups b and c display a negative anomaly for nb, ta and ti, which is atypical for n-morb, and indicates an input of a subduction component. these compositional patterns designated as n-morb-type with arc signatures (shervais, 2001) are very common in mafic rocks of the dinaric ophiolites (lugović et al., 1991; trubelja et al., 1995). the absence of a subduction component input [(nb/la)n = 0.950.99; (ti/gd)n = 0.97-1.00] is only observed in the gabbro samples of the group a that are generated during the early jurassic (fig. 8a1). the highest input of subduction related components [(nb/la)n = 0.32-0.42; (ti/gd)n = 0.78-0.85] is recorded in the late jurassic edenite gabbro samples of group b and suggests generation in an upper plate during intra-oceanic convergence. in these respects, they are very similar to the amphibole gabbros from the nearby mt. medvednica ophiolite mélange (fig. 8a1). however, the early cretaceous gabbros of group c, show intermediate values [(nb/la)n = 0.58-0.69; (ti/gd)n = 0.74-1.07; fig. 8a2] between the gabbros of the former groups. the analysed gabbros display similar chondrite normalized ree profiles at very different relative concentration levels which are characterized by flat patterns with a slight depletion in the lree (figs. 8b1 and 8b2). the intensity of lree depletion expressed as (la/sm)cn increases from the representative early jurassic (group a) via the early cretaceous (group c) to the late jurassic (group b) gabbroic rocks figure 8: (a1, a2) n-morb normalised multi-element diagram and (b1, b2) ree patterns for the kalnik and ivanščica mts. gabbroic rocks and dacite. normalisation values are from sun and mcdonough (1989). patterns for middleto late jurassic isotropic gabbros in the mt. medvednica ophiolite mélange (slovenec & lugović, 2008) are plotted for correlation constraints. † lugović et al.: petrology, geochemistry and tectono-magmatic affinity of gabbroic olistoliths from the ophiolite mélange in the nw dinaric-vardar ... geologia croatica 39 (0.79, 0.73-0.77 and 0.48-0.49, respectively). this is consistent with overall depletion of the samples shown by the concentration levels of their ree patterns (figs. 8b1 and 8b2). the dacite dyke and host diorite from the gotalovec quarry show mree to hree profiles 40-46 times relative to chondrite and represent highly fractionated compositions. the calculated range of eu anomalies (0.77-1.09) is typical for fractionation and minor accumulation of plagioclase in the individual samples, respectively. the measured 143nd/144nd ratios of gabbroic rocks are similar and vary from 0.512923 to 0.512964 which corresponds to respective initial εnd(t) values ranging from +5.41 to +6.43 (table 4). the 87sr/86sr ratios range from 0.703208 to 0.704316 and correspond to respective initial ratios of 0.703122 to 0.703977. the initial εnd and 87sr/86sr ratios of the representative early jurassic (group a) gabbroic rock plot in the morb field, while the all other representative late jurassic (group b) and early cretaceous (group c) gabbro samples plot in the field of recent island-arc and backarc analogues (fig. 9). 7. prevously published and new isotopic dating 7.1. k-ar dating previously published k-ar dating of the morb-type gabbro south from of the hruškovec quarry revealed an early jurassic (pliensbachian) age of 185 ± 6 ma (pamić, 1997). here, a gabbro from the same block [sample vsk-242/2 (fig. 2a, location 1)] is geochemically characterized and used as a representative for geochemical rock group a. new k-ar age data, presented here, are measured on plagioclase separated from gabbro [sample vsk-228/5 (fig. 2a, location 4)] of geochemical rock group b, and two gabbros [sample vsk-229/7 (fig. 2a, location 3) and vsi-8/1 (fig. 2b, location 3)] of geochemical rock group c. the results are presented in table 5. we interpreted the ages as the ages of rock consolidation. the time of rock consolidation (146.4 ± 3.4 ma) for gabbro which is used as a representative for geochemical rock group b in geological terms matches the late jurassic (tithonian). however, the other two ages (107.6 ± 4.2 ma and 103.4 ± 3.6 ma) obtained for babb-type gabbros which are used as representatives for geochemical rock group c in geological terms correspond to the latest early cretaceous (albian). 7.2. 40ar-39ar dating the results of the 40ar-39ar measurements on a magmatic amphibole (edenite table 1, fig. 4) separate of sample vsk228 (fig. 2a, location 4) are displayed in table 6 and figure 10. the initial heating steps indicate variable ages, steps 4-7 (with 70% of the released gas) suggest an apparent age of 147 ± 7 ma. the last step of the spectrum is higher than the mean age, indicating inherited argon (e.g. from high-temperature minerals like apatite). the ca/k spectrum (fig. 10b) is increasing, suggesting some contamination of the measured sample by a mineral degassing at lower temperatures than amphibole and containing more potassium rather than calcium. the plateau age of 147 ± 7 ma from sample vsk-228 seems to be geologically significant, especially considering the similar age (146.4 ± 3.4 ma) of sample vsk-228/5 from the same block obtained using k-ar dating. we interpreted this plateau age as the age of gabbro crystallisation. furthermore, it is (significantly) different in age from the gabbro south of the hruškovec quarry of 185 ± 6 ma. therefore, this late jurassic gabbro is also used as a representative for geochemical rock group b. 8. discussion and conclusions besides the dominant extrusive oceanic rock fragments, the kalnik unit also contains blocks of deep crustal sequences represented by ultramafic cumulates (lugović et al., 2007), as well as mafic cumulate and isotropic plutonic rocks (slovenec & lugović, 2008). the latter sequence, which was studied at the nearby mt. medvednica ophiolite mélange, comprises gabbro and predominant amphibole gabbro compositions, including a gabbro-pegmatite dated to 161.1 ± 2.1 ma (callovian-oxfordian) (slovenec & lugović, 2008). it was suggested that the mt. medvednica mafic-ultramafic crustal sequence represents remnants of a proto-arc–forearc system that was initiated in the rod in bathonian times (slovenec et al., 2011). isotropic gabbroic fragments are more abundant in the northern areas of the kalnik unit, in the kalnik and ivanščica mts. ophiolite mélange. in this work, the analysed gabbroic rocks are subdivided on the basis of petrographic and geochemical criteria into three groups (group a, b and c) which were isotopically dated to three distinct geological times. these gabbroic rocks show a similar overall bulk rock chemistry (fig. 8), isotopic compositions (fig. 9) and clinopyroxene compositions (fig. 5), that compare well with the analogues from the morb, iat and babb geotectonic environments, respectively. this particularly holds true for the early jurassic and early cretaceous representative gabbros, whereas the late jurassic gabbros, follow an iat trend also inferred for the middle-late jurassic isotropic gabbros from the nearby mt. medvednica ophiolite mélange, as analysed by slovenec & lugović (2008). 8.1. tectonomagmatic and petrogenetic significance a) geochemical group a – early jurassic gabbroic suite the amphibole-free gabbroic block [sample vsk-242/2 (fig. 2a, location 1)], from mt. kalnik, dated by pamić (1997) to 185 ± 6 (pliensbachian) has been assigned as the representative of the early jurassic geochemical group of rocks. its geochemical characteristics are the most akin to slightly evolved n-morb of all the analysed gabbro samples. this is evident from the normalized bulk rock chemistry (eg. multi-element abundance patterns normalized to n-type morb; fig. 8a1), initial nd-sr isotopic composition (fig. 9) as well as the highest clinopyroxene ti-abundances (fig. 6) and position of the rocks in the selected geotectonic discrimination diagrams geologia croatica 68/1geologia croatica 40 (fig. 11). the absence of the subduction component input expressed by the ratio (nb/la)n of 0.95-0.99, strongly suggests formation of the gabbroic rocks of group a at a ridge, spreading over a subducting slab at the terminal stage of the palaeotethyan slab break-off, which was previously dated to the bajocian (slovenec et al., 2011). the amphibole-free gabbro represents a plutonic sequence of crust formed during the early jurassic onset of ocean-floor spreading in the rod. the residual mantle where these early jurassic gabbros were fractionated from should have extracted around 5% of partial melt (fig. 12). however, a very high fertile mantle residuum (lherzolite) that is abundant in the cdob ophiolite complexes (lugović et al., 1991; bazylev et al., 2008) has not been previously observed in the rod mélanges. b) geochemical group b – late jurassic gabbroic suite a gabbroic crystallization sequence with magmatic amphibole, in this case edenite (table 1, fig. 4) represented in late jurassic samples vsk-228 and vsk-228/5 (fig. 2a, location 4), in the context of ophiolites, is typical for the fractionation of tholeiitic basalts, under low to medium pressures in suprasubduction settings (serri & saitta, 1980). it is atypical for mafic rocks from an ocean ridge (pearce et al., 1984). however, accessory amphibole may crystallize at the ocean floor near to transform faults (constantin, 1999) and mid-ocean ridges, where formation of ti-pargasite-tschermakite is confined to the late-magmatic evolution of an intrusive sequence as an interstitial phase with low abundance (tribuzio et al., 2000; coogan et al., 2001). figure 9: initial 143nd/144nd – 87sr/86sr isotope ratios diagram for the kalnik and ivanščica mts. gabbroic rocks showing the main oceanic mantle reservoirs of zindler & hart (1986). fields for middleto late jurassic isotropic gabbros in the mt. medvednica ophiolite mélange (slovenec & lugović, 2008) are plotted for correlation constraints. dm – depleted mantle, bse – bulk silicate earth, emi and emi ii – enriched mantle, himu – mantle with high u/pb ratio, prema – prevalent mantle composition. the mantle array is defined by many oceanic basalts and a bulk earth value for 87sr/86sr can be obtained from this trend. data for back-arc basin basalts babb (shaded field) compiled from wilson (1989) and references therein, cousens et al. (1994) and references therein, pearce et al. (1995), gribble et al. (1998) and ewart et al. (1998). data for mid-ocean ridge basalts morb (solid line) compiled from wilson (1989) and references therein and cousens et al. (1994), references therein and peate et al. (1997). data for oceanic island arcs and active continental margins iab (broken line) compiled from wilson (1989) and references therein, cousens et al. (1994) and references therein, pearce et al. (1995) and peate et al. (1997). the field for 87sr/86sr values affected by synor post-magmatic alteration in contact with seawater (light-grey shading) is from ustaszewski et al. (2009). figure 10: (a) 40ar/39ar step heating diagram of late jurassic gabbro amphibole (sample vsk-228) from the mt. kalnik ophiolite mélange. (b) ca/k spectrum. † lugović et al.: petrology, geochemistry and tectono-magmatic affinity of gabbroic olistoliths from the ophiolite mélange in the nw dinaric-vardar ... geologia croatica 41 in contrast, abundant magmatic amphibole is typical for rocks related to true subduction magmatism, sensu stern (2004) that is, for the rocks crystallized from melt derived from the mantle wedge, metasomatized by a flux of fluids released from the subducting slab. these volatile-rich magmas produced by hydrous melting of the mantle wedge (tatsumi figure 11: discrimination diagrams for the gabbroic rocks from the kalnik and ivanščica mts. ophiolite mélange. (a) v – ti/1000 diagram (shervais, 1982). iat = island-arc tholeiites, morb = mid-ocean ridge basalts, babb = back-arc basin basalts, cab = calc-alkaline basalts, cfb = continental flood basalts, oib = ocean-island basalts and ab = alkali basalts. (b) th – hf/3 – nb/16 diagram (wood, 1980). n-morb = normal mid-ocean ridge basalts, e-morb = enriched morb, wpt = within plate tholeiites, wpb = alkaline within plate basalts, cab = calc-alkaline basalts and iat = island-arc tholeiites. 1 crustal contamination; 2 ssz ophiolites trend; 3 morb ophiolites trend. (c) ta/yb – th/yb diagram (pearce, 1983). s subduction zone enrichment; c crustal contamination; w within-plate enrichment. n-morb, e-morb and oib are from sun & mcdonough (1989). t-morb is from geshi et al. (2007). data for back-arc basin basalts (babb) fields are from pearce et al. (1984), ewart et al. (1994) and leat et al. (2000). (d) nbn – thn diagram. seven marked fields of different basaltic rock-type of albanide-hellenide ophiolites are from saccani et al. (2011). n-morb, e-morb and oib are from sun and mcdonough (1989). t-morb is from geshi et al. (2007). fields for middleto late jurassic isotropic gabbros in the mt. medvednica ophiolite mélange (slovenec & lugović, 2008) are plotted for correlation constraints. geologia croatica 68/1geologia croatica 42 figure 12: petrogenic model for gabbroic rocks from the kalnik and ivanščica mts. ophiolite mélange. highly differentiated rock samples vsi-5 and vsi7/1 from mt. ivanščica are omitted. partial melting lines: dm – depleted mantle source, pm – primitive mantle source (kostopoulos & james, 1992), oib – enriched mantle source (clague & frey, 1982). model parameters = spinel-lherzolite source (ol57-opx25.5-cpx15-sp2.5), melting proportion = ol1.21-opx8.06cpx76.37-sp14.36, distribution coefficients are from kostopoulos & james (1992). fractional crystallization lines: initial magma = 10% melting of dm and pm mantle source, respectively, fractionated mineral assemblage = ol30-cpx40-pl30, distribution coefficients are from chen et al. (1990). data for n-morb, e-morb are from sun & mcdonough (1989). field for middleto late jurassic isotropic gabbros in the mt. medvednica ophiolite mélange (slovenec & lugović, 2008) are plotted for correlation constraints. larly in la (lugović et al., 1991; bazylev et al., 2008). subsequent subduction related enrichment of these peridotites in the mantle wedge will never increase la (as well as other lree) concentration to an extent capable of producing a typical iat ree pattern of partial melts (slovenec & lugović, 2009). the late jurassic iat-type amphibole gabbro is derived from the plutonic sequences of crust formed in the upper plate during initial subduction in the rod. according to the la/yb vs. la diagram (fig. 12), the analyzed late jurassic gabbros from mt. kalnik, represent crust derived from a depleted mantle wedge that suffered around 13-17% partial melting. amphibole-bearing transitional harzburgites inserted within the campanian-maastrichtian rudist limestones from gornje orešje in nearby mt. medvednica (lugović et al., 2007) with u-shaped ree patterns and slightly depleted spinel compositions (mg# ~ 0.67; cr# ~ 0.41) consistent with ~ 15% partial melting, perfectly matches the residual mantle after extraction of the parental melt. another transitional harzburgite slice from gornje orešje showing a more depleted spinel composition (mg# ~ 0.56; cr# ~ 0.45) which is consistent with ~ 20% partial melting, may represent vestiges of the residual mantle from where the mt. medvednica gabbros were derived. the geochemical signatures of the gabbro samples vsk228 and vsk-228/5 indicate magmatism at around ~ 147 ma (tithonian) related to a nascent island-arc setting. since this age is younger than those obtained on island-arc basalt from & eggins, 1995) crystallize amphibole-bearing mafic-ultramafic rock associations, either in island-arcs or continental margins (conrad & kay, 1984; debari & coleman, 1989; claeson & meurer, 2004; kocak et. al., 2005). based on their strong mineralogical and geochemical similarities with recent or ancient lithological analogues, most of the blocks representing the oceanic plutonic succession archived in the kalnik and medvednica mts. ophiolite mélange, must have formed in a supra-subduction setting. samples vsk204, vsk-228, vsk-228/2 and vsk-228/5 from mt kalnik (fig. 2a, location 2 and 5), systematically plot in the field of islandarc tholeiites (fig. 6 and 11). they show a strong subductionrelated signature expressed as negative hfse anomalies (fig. 8a1). initial εnd and 87sr/86sr ratio (fig. 9) also indicates their supra-subduction origin. at the same time, the sample shows significant depletion of lree (fig. 8b1), which is a peculiar geochemical feature of late middleto late jurassic suprasubduction magmatism, recorded by the extrusive blocks in the kalnik and ivanščica mts. ophiolite mélange (slovenec et al., 2011). the amphibole gabbros from the nearby mt. medvednica ophiolite mélange (fig. 1a-b), although apparently older (~ 161 ma; slovenec & lugović, 2008), are more influenced by subduction related components (fig. 6, 8 and 11). this suggests that the mantle wedge had been previously depleted in lree by very small increments of melt removal, possibly similar to that for the mantle lherzolites in the cdob, which are extremely depleted in lree, particu† lugović et al.: petrology, geochemistry and tectono-magmatic affinity of gabbroic olistoliths from the ophiolite mélange in the nw dinaric-vardar ... geologia croatica 43 ivanščica mt. (154 ± 8.7 ma; see slovenec et al., 2011), this is the youngest measured age concerning the late jurassic intra-oceanic subduction related crust in the rod. c) geochemical group c – early cretaceous gabbroic suite the gabbroic blocks represented by samples vsk-229/7 from mt. kalnik and vsi-8/1 from mt. ivanščica, dated to the latest early cretaceous (albian) have been adopted as the representative samples of group c. this group also includes undated isotropic gabbro samples with the same or very similar geochemical and mineralogical compositions and characteristics (table 1-3, fig. 4-9 and 11). gabbros from this block contain minor amounts of edenite (table 1; fig. 4), suggesting crystallization from a volatile-bearing magma. given the bulk rock chemistry, (table 3; fig. 8) and host clinopyroxene composition (table 2; fig. 6), the gabbros show transitional geochemical signatures between the early jurassic n-morbtype gabbros of group a and the late jurassic iat-type gabbros of group b. geochemical features compiled from selected discrimination diagrams (fig. 11) as well as initial εnd and 87sr/86sr ratios (fig. 9) indicate the babb-type affinity of this gabbroic group that clearly forms a discrete trend (fig. 11b and 11d). this suggests that the rock suite of group c may represent cogenetic crustal fragments derived from a similar mantle source. these early cretaceous gabbros are formed in an ensimatic back-arc marginal basin of the rod. since those gabbros reflect basaltic liquids (fig. 7a), their compositions may be used for petrogenetic modelling. the representative gabbro samples and other members of the group, except gotalovec quarry samples, show ~ 7-9% total partial melting (fig. 12). however, the gotalovec quarry sample gtc-4, albeit being slightly fractionated, may reflect melts derived from a comparatively slightly more depleted mantle source. the other three gotalovec quarry gabbros are moderately fractionated (fig. 12). the highly serpentinized lherzolite from the mt. kalnik metamorphic sole, that has undergone 7% of partial melting (lugović et al., 2007), perhaps could be compositionally reminiscent of the mantle residue of these representative gabbros. the kalnik lherzolite is lree depleted due to very small increments of melt removal and in this respect closely resembles jurassic mantle lherzolites from the cdob ophiolite complexes (lugović et al., 1991; bazylev et al., 2008). the existence of early cretaceous oceanic crust in the rod may be inferred from protoliths of the almandine amphibolite facies metamorphic sole, welded beneath the mt. kalnik lherzolite (lugović et al., 2007). the metamorphic sole includes babb-type protoliths from plutonic and extrusive sequences that were metamorphosed at 118 ± 8 ma (ignjatić, 2007). the formation of a metamorphic sole bears witness to the termination of spreading and indicates the initial stages of convergence in an oceanic basin, wherein the youngest oceanic crust and parental mantle are involved in a contact dynamo-thermal interaction (e.g. insergueixfilippi et al., 2000; wakabayashi & dilek, 2000, 2003). the amphibolite-lherzolite composite slice from mt. kalnik is tectonically emplaced into palaeocene carbonate breccias and represents the remnant that provides the crucial key to understanding the tectonomagmatic evolution in the final oceanic stage of the rod. unfractionated and least fractionated samples of group c from figure 12 resemble the geochemical characteristics of the aptian metamorphic sole protoliths (fig. 11b and 11d), and may be interpreted as crust formed in an early cretaceous back-arc basin. alternatively, a similar rock suite may have formed during the subduction of an active ridge (e.g. bortollotti et al., 2002), when an enormous volume of magma generated in a relatively short period of time, creates incipient crust in the leading edge of the upper (overriding) plate (e.g. stern & bloomer, 1992). from this standpoint, the same rock suite should be relatively younger than in the model that assumes its formation at a back arc basin spreading ridge. however, a full time range of crust formation in the cretaceous back-arc basin of the rod requires extensive dating. the composite gabbroic megablock from the gotalovec quarry (fig. 2b, location 5) shows a high level of magma fractionation resulting in minor diorite, and finally in the intersecting tholeiitic dacite. these petrogenetic characteristics of the rocks reflect pressure release melting, fractionation and formation of felsic compositions which is analogous with crust formation during the early stage of widening in the modern back-arc basin (sinton et al., 2003). continuous normal zoning observed in edenite suggests fractional crystallization in a closed, deep-seated magma system (stern, 1979). the edenite aland ti-content thermobarometer (ernst & liu, 1998) suggests the crystallization pressures and temperatures for the gotalovec megablock were 0.6 gpa at 860 °c. their petrological characteristics suggest formation at a slow-rate spreading ridge of a marginal basin. however, the alteration pattern of the gotalovec quarry gabbroic plutonic rocks is, according to the evidence, in many ways similar to that of accreted island-arc terrains reported by mahlburg & kay (1983), particularly concerning exsolved mn-rich ilmenite. assuming the type of alterations atypical for ridge crust, gotalovec quarry deep crustal rocks must have acted as the leading edge of a back-arc upper plate. the cretaceous back-arc basin mantle from the rod is comparable in most mineralogical and geochemical features to mantle peridotites from the early jurassic cdob ophiolites. this may suggest that it was not affected by the subduction that commenced in the rod in the middle jurassic (bathonian). if these assumptions concerning gabbroic rocks are generally correct, then rifting and formation of the backarc spreading centre must have initiated in the early jurassic (or older ?) lithosphere behind the island-arc. the mode of back-arc opening in the rod is apparently different to that proposed for most modern back-arc basins (see martinez et al., 2007). 8.2. improved geodynamic model for the rod in geotectonic modelling of the neo-tethyan realm, the rod ophiolites belong to its easternmost segment (bortolotti & principi, 2005). disagreement exists as to whether the fragmented rod oceanic lithosphere, including lithosphere related to the advanced stage rifting has a digeologia croatica 68/1geologia croatica 44 figure 13: improved schematic geodynamic model for the evolution the repno oceanic domain as a corner domain connecting the meliata-maliak and dinaric-vardar oceanic systems. (a) the first spreading stage and formation of ensialic back-arc basin. (b) the early stage of the first subduction in the rod with formation of an infant proto-arc. (c) the evolved subduction stage with initiation of an island arc and formation of the subsequent ensimatic marginal (back-arc) basin. (d) ongoing spreading in the back-arc basin – the second spreading stage in the rod. (e) subduction in the back-arc basin – the second subduction stage in the rod with the formation of a proto-arc (?) in the overriding plate. (f) the closure stage of the rod. 1 – mantle diapir, 2 – oceanic crust with radiolarian cherts, 3 – raising of the mantle diapir, 4 – melting zone; ap = accretionary prism bab = back-arc basin, pa = cretaceous proto-arc. 2005; slovenec & lugović, 2008, 2009; slovenec et al., 2010, 2011). however, the rod indeed represents a corner stone domain between these two oceanic systems naric-vardar oceanic provenance (e.g. pamić, 1997; haas & kovács, 2001; kiss et al., 2012), or is a segment of the meliata-maliak oceanic system (e.g.goričan et al., † lugović et al.: petrology, geochemistry and tectono-magmatic affinity of gabbroic olistoliths from the ophiolite mélange in the nw dinaric-vardar ... geologia croatica 45 (fig. 1c), which for example after babić et al., (2002) and schmid et al. (2008), are assumed to be integral parts of one and the same ocean basin. in general, all parts of the oceanic domain shared a common tectonomagmatic evolution throughout the mesozoic, although some events might be locally specific and diachronous. the data presented here chronologically defines the late stage of early jurassic spreading, a nascent stage of island-arc formation in the late jurassic, and may suggest the existence of a cretaceous back-arc marginal basin from the sava-vardar suture zone (pamić, 2002) or, in other words, from the inner part of the western vardar ophiolite unit (schmid et al., 2008). therefore, the results presented in this work only complement the previously proposed segmental model of the geodynamic evolution of the rod. the proposed model of the geodynamic evolution of the rod presented in this paper represents a comprehensive model based on all the up to date published research results (see slovenec & lugović 2009, 2012; slovenec et al., 2010, 2011). in the framework of the dinaric-vardar oceanic provenance, the rod probably commenced its geodynamic evolution as an ensialic back-arc basin formed behind a peri-continental volcanic arc, related to andean-type subduction of the palaeo-tethyan lithosphere beneath the european continental margin (stampfli & borel, 2002, 2004; goričan et al., 2005). alternatively, it may have formed as a westward prograding embayment of the neo-tethys ocean (see discussion in pamić et al., 2002; robertson et al., 2009). the oldest record of rifting of the intra-continental lithosphere behind the peri-continental volcanic arc was dated as late anisian, specifically as illyrian (slovenec et al., 2010). the advanced stage rifting is characterized by pelagic carbonate peperites (halamić et al., 1998; palinkaš et al., 2000, 2008). the onset of rifting created a rift basin with pelagic sediments and within plate alkali basalt type crust (slovenec et al., 2010, 2011; kiss et al., 2012). this basin was located between the future adriatic microplate and the continental edge of south laurussia (represented by pieces of the recent alcapa, dacia and tisza mega-unit; fig. 1a-b), at least in the early ladinian. the oldest spreading ridge oceanic crust related to the proto-oceanic stage (first spreading stage in the rod) is represented by enriched e-morb-type extrusive rocks formed in the early ladinian, particularly the late fassanian, and was followed by depleted e-morb-type crust in the late ladinian, t-morb-type crust in the middle carnian and the first appearance of nmorb-type crust in the late carnian (slovenec et al., 2011; fig. 13a). such a regular chemostratigraphic succession of ridge crust formation through the opening of an ocean reflects a slow spreading rate (eg. wilson, 1989). the t-morb-type and n-morb-type crust formed during spreading from the middle to late carnian, displays slight supra-subduction characteristics inherited from the middle triassic subduction of the palaeo-tethys (or an earlier subduction?). the inherited ssz characteristics systematically diminished through the onset of spreading after the late carnian and completely disappeared until the bajocian oceanic crust due to the subducting slab-break-off (slovenec & lugović, 2009). therefore the bajocian crust is assumed to represent the maximum evolved stage of spreading in the rod (slovenec & lugović, 2012). however, this work suggests that the sinking slab should have already broken-off in the pliensbachian (fig. 13a). intra-oceanic convergence (the first stage of subduction in the rod) commenced in the late middle jurassic (late bathonian) as recorded by subduction of an active oceanic ridge and production of “n-morb with arc signature” crust in the overriding plate (slovenec & lugović, 2009; fig. 13b). at this stage magmatism was not related to a significantly metasomatized mantle wedge (sensu stern (2004) and whatam & stern (2011)), and does not represent true subduction derived igneous activity. due to the onset of spreading accompanied by progressive metasomatism of the mantle wedge during the callovian-oxfordian, the iat-type crust was produced in an infant proto-arc extensional setting (slovenec et al., 2011; fig. 13b). the youngest iat-type edenite gabbro dated here as tithonian represents the youngest crust related to the first subduction event in the rod that reflects the nascent stage of formation of an intra-oceanic volcanic arc. although the amphibolebearing gabbroic rocks from the nearby mt. medvednica ophiolite mélange (slovenec & lugović, 2008) are more influenced by subduction related components, they show older formational ages (~ 161 ma vs. ~ 147 ma). this inverse chemostratigraphic evolution suggests that true ssz magmatism might have been delayed and/or was diachronous during the onset of the first subduction event in the rod. moreover, it indicates specific metasomatically induced thermal regimes of hydrous partial melting along the subduction front (fig. 13c). a modern fore-arc progressed over a period of about 15 ma to a mature island arc, accompanied by a coeval and cognate back-arc basin (stern et al., 1996; bloomer et al., 1995). rocks typical for a mature island-arc, such as calcalkaline extrusives, have not yet been reported for the rod and represent a missing link needed to complete the geodynamic model. the back-arc marginal basin in the rod must have formed during the early cretaceous, but it is not clear when the spreading (second spreading stage in the rod) commenced (fig. 13d). the early cretaceous babb-type lower crust and related mantle peridotites from the rod show evidence against island-arc involvement in the rifting. therefore the rifting must have initiated behind the island-arc and led to formation of the extensional back-arc basin. the metamorphic sole derived from babb-type crust dated to 118 ± 8 ma (ignjatić, 2007) indicates termination of back-arc spreading in the basin during the aptian. simultaneously, a thick island-arc crust was emplaced onto the continental margin of the adriatic plate, forming the mt. medvednica lower greenschist facies metamorphic complex, and consists of rocks of both pericontinental and oceanic provenance (lugović et al., 2006, with references). since the greenschists derived from iat-protoliths dated to 119 ± 5 ma (belak et al., 1995), the formation of the metamorphic sole in geologia croatica 68/1geologia croatica 46 the back-arc basin, and the emplacement of the island-arc onto the adriatic continental margin, did not appear as sequential events. formation of oceanic crust in the rod must have continued after the aptian, and obviously in the upper plate (second subduction stage in the rod; fig. 13e). this is indicated by the youngest early cretaceous (albian) ophiolites back-arc affinity of rock group c. the back-arc basins or marginal basins located in front of the tisza-dacia megaunits, where the oceanic crust was formed during the latest early cretaceous to early campanian (e.g.ustaszewski et al., 2009 with references therein), (referred to as ophiolites of rock group c), are included in the sava-vardar zone (pamić, 2002; fig. 1a), or simply the sava zone (schmid et al., 2008). this sava-vardar zone is thought to be a suture zone between the dinarides and fragments of the european continental margin (fig. 1a). following this model, the rod back-arc basin from the aptian (formation of metamorphic sole) onwards, may be interpreted as one of several discrete marginal basins stretching along the sava-vardar-izmir-ankara-erzinam suture zone. the next cretaceous marginal basin domain of this suture zone may be envisaged in north kozara in the southeast (fig. 1a) where campanian bimodal magmatic succession reflects its stage of closure (ustaszewski et al., 2009; model b2). the rod back-arc basin closed to a great extent during the latest late cretaceous (fig. 13f) as deduced from peridotite clasts in campanian basal conglomerates (halamić, 1998), subaerial weathering of peridotites into ni-lateritic crust (palinkaš et al., 2006) and composite peridotiteamphibolite slices tectonically emplaced into palaeocene breccias (lugović et al. 2007). acknowledgement this work is the contribution to the scientific projects: mesozoic magmatic, mantle and pyroclastic rocks of northwestern croatia (grant no. 181-1951126-1141 to da. s.) and tectonomagmatic correlation of fragmented oceanic lithosphere in the dinarides (grant no. 195-1951126-3205 to b. l.), carried out under the support of the croatian ministry of science, education and sport. critical comments by vesnica garašić and an anonymous reviewer greatly helped to achieve final version of the manuscript. references babić, lj., hochuli, p.a. & zupanič, j. (2002): the jurassic ophiolitic mélange in the ne dinarides: dating, internal structure and geotectonic implications.– eclogae geologicae helvetiae, 95, 263–257. balen, d., schuster, r. & garašić, v. (2003): the kamenjača olivine gabbro from moslavačka gora (south tisia, croatia).– rad hrvatske akademije znanosti i umjetnosti, 486, 57-76. bazylev, b.a., popević, a., karamata, s., kononkova, n.n., simakin, s.g., olujić, j., vujnović, l. & memović, e. (2008): mantle peridotites from the dinaridic ophiolite belt and the vardar zone western belt, central balkan: a petrological comparison.– lithos, 108, 37–71. beccaluva, l., macciotta, g., piccardo, g.b. & zeda, o. (1989): clinopyroxene composition of ophiolite basalts as petrogenetic indicator.– chemical geology, 77, 165–182. belak, m., pamić, j., kolar-jurkovšek, t., pecskay, z. & karan, d. (1995): alpine low-grade regional metamorphic complex of mt. medvednica (northwest croatia).– in: i. vlahović, i. velić & m. šparica (eds.): 1st croatian geological congress proceedings. institute of geology, zagreb, 67–70 (in croation with english summary). bloomer, s.h., taylor, b., macleod, c.j., stern, r.j., fryer, p., hawkins, j.w. & johnson, l. (1995): early arc volcanism and the ophiolite problem; a perspective from drilling in the western pacific.– in: b. taylor & j. natland (eds.): active margins and marginal basins of the western pacfic. geophysical monograph, american geophys union, 88, 1–30. bortolotti, v., marroni, m., pandolfi, l., principi, g. & saccani, e. (2002): interaction between mid-ocean ridge and subduction magmatism in albanian ophiolites.– journal of geology, 110, 561–576. bortolotti, v. & principi, g. (2005): tethyan ophiolites and pangea break-up.– island arc, 14, 442–470. chen, c.y., frey, f.a. & garcia, m.o. (1990): evolution of alkalic lavas at haleakala volcano, east maui, hawaii.– contributions to mineralogy and petrology, 105, 197–218. claeson, d.t. & meurer, w.p. (2004): fractional crystallization of hydrous basaltic ‘arc-type’ magmas and the formation of amphibole-bearing gabbroic cumulates.– contributions to mineralogy and petrology, 147, 288–304. clague, d.a. & frey, f.a. (1982): petrology and trace element geochemistry of the honolulu volcanism, oahu: implications for the oceanic mantle below hawaii.– journal of petrology, 23, 447–504. colombi, a. (1989): métamorphism et geochemie des roches mafiques des alpes ouest-centrales (géoprofil viěge-domodos-solalocerano).– mémories de géologie (lausanne), 4, 1–216. conrad, w.k. & kay, r.w. (1984): ultramafic and mafic inclusions from adak islands: crystalization history, and implications for the nature of primary magmas and crustal evolution in the aleutian arc.– journal of petrology, 25, 88–125. constantin, m. (1999): gabbroic intrusion and magmatic metasomatism in harzburgites from the garrett transform fault: implication for the nature of the mantle-crust transitional fast-spreading ridges.– contributions to mineralogy and petrology, 136, 111–130. coogan, l.a. (2003): contamination of the lower oceanic crust in the oman ophiolite.– geology, 3, 1065–1068. coogan, l.a., wilson, r.n., gillis, k.m. & macleod, c.j. (2001): near-solidus evolution of oceanic gabbros: insights from amphibole geochemistry.– geochimica et cosmochimica acta, 65, 4339–4357. cousens, b.l., allan, j.f. & gorton, m.p. (1994): subductionmodified pelagic sediments as the enriched component in back-arc basalts from the japan sea: ocean drilling program sites 797 and 794.– contributions to mineralogy and petrology, 117, 421–434. cox, k.g., bell, j.d. & pankhust, r.j. (1979): the interpretation of igneous rocks.– london, uk: george allen and unwin, 450 p. crnković, b., babić, v. & tomašić, i. (1974): the gabbro of hruškovec near ljubeščica on mount kalnik (northern croatia).– geološki vjesnik, 27, 153–171 (in croatian with english summary). debari, s.m. & coleman, r.g. (1989): examination of deep levels of an island arc: evidence from the tonsina ultramafic-mafic assemblage, tonsina, alaska.– journal of geophysical research, 94, 4373–4391. ernst, w.g. & liu, j. (1998): experimental phase-equilibrium study of aland ti-contents of calcic amphibole in morb – a semiquantitative thermobarometer.– american mineralogist, 83, 952–969. † lugović et al.: petrology, geochemistry and tectono-magmatic affinity of gabbroic olistoliths from the ophiolite mélange in the nw dinaric-vardar ... geologia croatica 47 ewart, a., bryan, w.b., chappell, b.w. & rudnick, r.l. (1994): 24. regional geochemistry of the lau-tonga arc and back arc system.– in: j. hawkins, l. parson & j. allan (eds.): the ocean drilling program proceedings, scientific results, 135, 385–425. ewart, a., collerson, k.d., regelous, m., wendt, j.i. & niu, y. (1998): geochemical evolution within the tonga-kermadec-lau arc-back-arc system: the role of varying mantle wedge composition in space and time.– journal of petrology, 39, 331–368. festa, a., pini, g.a., dilek, y. & codegone, j. (2010): mélanges and mélange-forming processes: a historical overview and new concepts.– in: y. dilek (ed.): alpine concept in geology. international geology review, 52, 1040–1105. geshi, n., umino, s., kumagai, h., sinton, j.m., white, s.m., kisimoto, k. & hilde, t.w. (2007): discrete plumbing systems and heterogeneous magma sources of a 24 km3 off-axis lava field on the western flank of east pacific rise, 14° s.– earth and planetary science letters, 258, 61–72. goričan, š., halamić, j., grgasović, t. & kolarjurkovšek, t. (2005): stratigraphic evolution of triassic arcbackarc system in northwestern croatia.– bulletin de la societe géologique de france, 176, 3–22. gribble, r.f., stern, r.j., newman, s., bloomer, s.h. & o`hearn, t. (1998): chemical and isotopic composition of lavas from the northern mariana trough: implications for magmagenesis in back-arc basins.– journal of petrology, 39, 125–154. haas, j., mioč, p., pamić, j., tomljenović, b., árkai, p., bérczi-makk, a., koroknai, b., kovács, s. & r-felgenhauer, e. (2000): complex structural pattern of the alpinedinaridic pannonian triple junction.– international journal of earth sciences, 89, 377–389. haas, j. & kovács, s. (2001): the dinaridic-alpine connection – as seen from hungary.– acta geologica hungarica, 44, 345–362. halamić, j. (1998): lithostratigraphy of jurassic and cretaceous sediments with ophiolites from the mts. medvednica, kalnik and ivanščica. phd thesis, university of zagreb, zagreb, 188 p. (in croatian with english summary). halamić j., slovenec, da. & kolar-jurkovšek, t. (1998): triassic pelagic limestones in pillow lavas in the orešje quarry near gornja bistra, medvednica mt. (northwest croatia).– geol. croatica, 51, 33–45. hébert, r.m., constantin, m. & robinson, p.t. (1991): primary mineralogy of leg 118 gabbroic rocks and their place in the spectrum of oceanic mafic igneous rocks.– in: r.p. von herzen, p.t. robinson et al. (eds.): the ocean drilling program proceedings, scientific results, 118, 3–20. ignjatić, s. (2007): upper cretaceous amphibolites from lherzolite metamorphic sole (kalnik mt., croatia).– unpubl. b.sc thesis, university of zagreb, zagreb, 61 p. (in croatian with english summary). insergueix-filippi, d., dupeyrat, l., dimo-lahitte, a., vergély, p. & bébien, j. (2000): albanian ophiolites. ii – model of subduction zone infancy at a mid-ocean ridge.– ofioliti, 25, 47–53. judik, k., rantitsch, g., rainer, t.m., arkai, p. & tomljenović, b. (2008): alpine metamorphism of organic matter in metasedimentary rocks from mt. medvednica (croatia).– swiss journal of geosciences, 101, 605–616. kiss, g., molnár, f., palinkaš, l., kovács, s. & horvatović, h. (2012): correlation of triassic advanced riftingrelated neotethyan submarine basaltic volcanism of the darnó unit (ne-hungary) with some dinaridic and hellenidic occurrences on the basis of volcanological, fluid–rock interaction, and geochemical characteristics.– int. j. earth sci., 101, 1503–1521. kocak, k., isik, f., arslan, m. & zedef, v. (2005): petrological and source region characteristics of ophiolitic hornblende gabbros from the aksarav and kavseri regions, central anatolian crystalline complex, turkey.– journal of asian earth sciences, 25, 883–891. kostopoulos, d.k. & james, s.d. (1992): parameterization of the melting regime of the shallow upper mantle and the effects of variable lithospheric stretching on mantle modal stratification and trace element concentrations in magmas.– journal of petrology, 33, 665–691. leake, b.e. et al. (1997): nomenclature of amphiboles: report of the subcommittee on amphiboles of the international mineralogical association, commission on new minerals and mineral names.– canadian mineralogist, 35, 219–246. leat, p.t., livermore, r.a., millar, i.l. & pearce, j.a. (2000): magma supply in back-arc spreading centre segment e2, east scotia ridge.– journal of petrology, 41, 845–866. ludwig, k. (2005): isoplot/ex v.3, usgs open file report. lugović, b., altherr, r., raczek, i., hofmann, a.w. & majer, v. (1991): geochemistry of peridotites and mafic igneous rocks from the central dinaric ophiolite belt, yugoslavia.– contributions to mineralogy and petrology, 106, 201–216. lugović, b., šegvić, b. & altherr, r. (2006): petrology and tectonic significance of greenschists from the medvednica mts. (sava unit, nw croatia).– ofioliti, 31, 39–50. lugović, b., slovenec, da., halamić, j. & altherr, r. (2007): petrology, geochemistry and geotectonic affinity of the mesozoic ultramafic rocks from the southwesternmost mid-transdanubian zone in croatia.– geologica carpathica, 58, 511–530. mahlburg, v. & kay, s. (1983): metamorphism in the aleutian arc: the finger bay pluton, adak, alaska.– canadian mineralogist, 2l, 665–681. martinez, f., okino, k., ohara, y., reysenbach, a-m. & goffredi, s.k. (2007): back-arc basins.– oceanography, 20, 117–127. meli, s., montanini, a., thöni, m. & frank, w. (1996): age of granulite blocks from the external linguride units (northern apennines, italy).– memorie di scienze geologiche, padova, 48, 65–72. mcculloch, m.t., gregory, r.t., wasserburg, g.j. & taylor jr., h.p. (1981): sm-nd, rb-sr, and 18o/16o isotopic systematics in an oceanic crustal section: evidence from the samail ophiolite.– journal of geophysical research, 86, 2721–2735. miller, ch. & thöni, m. (1997): eo-alpine eclogitisation of permian morb-type gabbros in the koralpe (eastern alps, austria): new geochronological, geochemical and petrological data.– chemical geology, 137, 283–310. morimoto, n. (1988): nomenclature of pyroxenes.– schweizeriche mineralogische und petrogrographische mitteilungen, 68, 95–111. palinkaš, l.a., kolar-jurkovšek, t., borojević, s. & bermanec, v. (2000): triassic rifting magmatism within zagorje-mid-transdanubian zone, exampflied by pillow lavas of hruškovec, mt. kalnik, n. croatia, pancardi 2000 meeting.– geološke vijesti, 37, 98–99. palinkaš, l.a., bermanec, v., moro, a., dogančić, d. & strmić-palinkaš, s. (2006): the northernmost ni-lateritic weathering crust in the tethyan domain, gornje orešje, medvednica mt., mesozoic ophiolite belts of northern part of the balkan.– balkan peninsula proceedings, 97–101. palinkaš, l.a., bermanec, v., borojević-šoštarić, s., kolar-jurkovšek, t., strmić-palinkaš, s., molnár, f. & kniewald, g. (2008): volcanic facies analysis of a subaqueous basalt lava-flow complex at hruškovec, nw croatia – evidence of advanced rifting in the tethyan domain.– j. volc. geotherm. res. 178, 644–656. geologia croatica 68/1geologia croatica 48 pamić, j. (1997): the northwesternmost outcrops of the dinaridic ophiolites: a case study of the mt. kalnik (north croatia).– acta geologica hungarica, 40, 37–56. pamić, j. (2000): the periadriatic-sava-vardar suture zone.– in: i. vlahović & r. biondić (eds.): 2nd croatian geological congress proceedings. institute of geology, zagreb, 333–337 (in croatian with english summary). pamić, j. (2002): the sava-vardar zone of the dinarides and hellenides versus the vardar ocean.– eclogae geologicae helvetiae, 95, 99–113. pamić, j. & tomljenović, b. (1998): basic geological data on the croatian part of the mid-transdanubian zone as exemplified by mt. medvednica located along the zagreb-zemplen fault zone.– acta geologica hungarica, 41, 389–400. pamić, j., tomljenović, b. & balen, d. (2002): geodynamic and petrogenetic evolution of alpine ophiolites from the central and nw dinarides: an overview.– lithos, 65, 113–142. pearce, j.a. (1983): role of the sub-continental lithosphere in magma genesis at active continental margins.– in: c.j. hawkesworth & m.j. norry (eds.): continental basalts and mantle xenoliths. nantwich, uk: shiva, 230–249. pearce, j.a., lippard, s.j. & roberts, s. (1984): characteristics and tectonic significance of supra-subduction zone ophiolites.– in: b.p. kokelaar & m.f. howells (eds.): marginal basin geology, geol soc london, special publications, 16, 17–94. pearce, j.a., baker, p.e., harvey, p.k. & luff, i.w. (1995): geochemical evidence for subduction fluxes, mantle melting for fractional crystallization beneath the south sandwich island arc.– journal of petrology, 36, 1073–1109. peate, d.w., pearce, j.a., hawkesworth, c.j., colley, h., edwards, m.h. & hirose, k. (1997): geochemical variations in vanuatu arc lavas: the role of subducted material and a variable mantle wedge composition.– journal of petrology, 38, 1331–1358. poljak, j. (1942): a contribution to the knowledge of geology of the mt. kalnik.– vjestnik hrvatskog državnog geoložkog zavoda i hrvatskog državnog geoložkog muzeja, 1, 53–92 (in croatian with german summary). pouchou, j.l. & pichoir, f. (1984): a new model for quantitative analyses. i. application to the analysis of homogeneous samples.– la recherche aérospatiale, 3, 13-38. pouchou, j.l. & pichoir, f. (1985): “pap” (φ-ρ-z) correction procedure for improved quantitative microanalysis.– in: j.t. armstrong (ed.): microbeam analysis, san francisco, california, usa: san francisco press, 104–106. renne, p.r., mundil, r., balco, g., min, k. & ludwig, k.r. (2010): joint determination of 40k decay constants and 40ar*/40k for the fish canyon sanidine standard, and improved accuracy for 40ar/39ar geochronology.– geochimica et cosmochimica acta, 74, 5349–5367. renne, p.r., mundil, r., balco, g., min, k. & ludwig, k.r. (2011): response to the comment by w. h. schwarz et al. on “joint determination of 40k decay constants and 40ar/40k for the fish canyon sanidine standard, and improved accuracy for 40ar/39ar geochronology” by p.r. renne et al. (2010).– geochimica et cosmochimica acta, 75, 5097–5100. robertson, a., karamata, s. & šarić, k. (2009): overwiew of ophiolites and related units in the late palaeozoic-early cenozoic magmatic and tectonic development of tethys in the northern part of the balkan region.– lithos, 108, 1–36. saccani, e., beccaluva, l., photiades, a. & zeda, o. (2011): petrogenesis and tectono-magmatic significance of basalts and mantle peridotites from the albanian-greek ophiolites and sub-ophiolitic mélanges. new constraints for the triassic-jurassic evolution of the neo-tethys in the dinaride sector.– lithos, 124, 227–242. schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., scheffer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine-carpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss journal of geoscience, 101, 139–183. schwarz, w.h., kossert, k., trieloff, m. & hopp, j. (2011): comment on the “joint determination of 40k decay constants and 40ar*/40k for the fish canyon sanidine standard, and improved accuracy for 40ar/39ar geochronology” by paul r. renne et al. (2010).– geochimica et cosmochimica acta, 75, 5094–5096. schwarz, w.h. & trieloff, m. (2007): intercalibration of 40ar-39ar age standards nl-25, hb3gr hornblende, ga1550, sb-3hd-b1 biotite and bmus/2 muscovite.– chemical geology, 242, 218–231. serri, g. & saitta, m. (1980): fractionation trends of gabbroic complexes from high-ti and low-ti ophiolites and from the crust of major oceanic basins: a comparison.– ofioliti, 5, 241–264. serri, s. (1981): the petrochemistry of ophiolitic gabbro-complexes: a key for classification of ophiolites to low-ti and high-ti types.– earth and planetary science letters, 52, 203–212. shervais, j.w. (1982): ti-v plots and petrogenesis of modern and ophiolitic lavas.– earth and planetary science letters, 59, 101–118. shervais, j.w. (2001): birth, dead, and resurrection: the life cycle of supra-subduction zone ophiolites.– geochemistry, geophysics, geosystems, 2, 1010, 45 p. [doi: 10 1029/2000gc000080]. sinton, j.m., ford, l., chappell, b. & mcculloch, m. (2003): magma genesis and mantle heterogeneity in the manus back-arc basin, papua new guinea.– journal of petrology, 44, 159–195. slovenec, da. & lugović, b. (2008): amphibole gabbroic rocks from the mt. medvednica ophiolite mélange (nw croatia): geochemistry and tectonic setting.– geologica carpathica, 59, 277–293. slovenec, da. & lugović, b. (2009): geochemistry and tectonomagmatic affinity of extrusive and dyke rocks from the ophiolite mélange in the sw zagorje-mid-transdanubian zone (mt. medvednica, croatia).– ofioliti, 34, 63–80. slovenec, da. & lugović, b. (2012): evidence of the spreading culmination in the eastern tethyan repno oceanic domain assessed by the petrology and geochemistry of n-morb extrusive rocks from the mt. medvednica ophiolite mélange (nw croatia).– geologia croatica, 65, 435–446. slovenec, da., lugović, b. & vlahović, i. (2010): geochemistry, petrology and tectonomagmatic significance of basaltic rocks from the ophiolite mélange at the nw external-internal dinarides junction (croatia).– geologica carpathica, 61, 273–294. slovenec, da., lugović, b., meyer, h-p. & garapićšiftar, g. (2011): a tectono-magmatic correlation of basaltic rocks from ophiolite mélanges at the north-eastern tip of the savavardar suture zone, northern croatia, constrained by geochemistry and petrology.– ofioliti, 36, 77–100. sölva, h., grasemann, b., thöni, m., thiede, r. & habler, g. (2005): the schneeberg normal fault zone: normal faulting associated with cretaceous se-directed extrusion in the eastern alps (italy/austria).– tectonophysics, 401, 143–166. stampfli, g.m. & borel, g.d. (2002): a plate tectonic model for the paleozoic and mesozoic constrained by dinamic plate boundaries and restored synthetic ocean isochrons.– earth and planetary science letters, 196, 17–33. stampfli, g.m. & borel, g.d. (2004): the transmed transects in space and time: constraints on the paleotectonic evolution of the mediterranean domain.– in: w. cavazza, f. roure, w. spakman, g.m. stampfli & p.a. ziegler (eds.): the transmed atlas: the mediterranean region from crust to mantle. heidelberg, germany, springer, 53–80. † lugović et al.: petrology, geochemistry and tectono-magmatic affinity of gabbroic olistoliths from the ophiolite mélange in the nw dinaric-vardar ... geologia croatica 49 steiger, r.h. & jäger, e. (1977): subcommission on geochronology: convention on the use of decay constants in geoand cosmochronology.– earth and planetary science letters, 36, 359–362. stern, c. (1979): open and closed system igneous fractionation within two chilean ophiolites and tectonic implication.– contributions to mineralogy and petrology, 68, 243–258. stern, c. (2004): subduction initiation: spontaneous and induced.– earth and planetary science letters, 226, 275–292. stern, r.j. & bloomer, s.h. (1992): subduction zone infancy: examples from the eocene izu-bonin-mariana and jurassic california arcs.– geological society of america bulletin, 104, 1621–1636. stern, r.j., bloomer, s.h., martinez, f., yamazaki, t. & harrison, t.m. (1996): the composition of back-arc basin lower crust and upper mantle in the mariana trough: a first report.– island arc, 5, 354–372. sun, s.s. & mcdonough, w.f. (1989): chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes.– in: a.d. saunders & m.j. norry (eds.): magmatism in ocean basins. geological society of london, special publications, 42, 313–345. šimunić, an. & pamić, j. (1989): ultramafic rocks from the neighbourhood of gornje orešje on the northwestern flanks of mt. medvednica (northern croatia).– geološki vjesnik, 42, 93–101. šimunić, an., pikija, m., hećimović, i. & šimunić, al. (1981): osnovna geološka karta sfrj 1:100000. tumač za list varaždin [basic geological map of sfry 1:100000, geology of the varaždin sheet – in croatian].– institut za geološka istraživanja zagreb, savezni geološki zavod beograd, 1–81. šimunić, an., pikija, m. & hećimović, i. (1982): osnovna geološka karta sfrj 1:100000, list varaždin [basic geological map of sfry 1:100000. varaždin sheet – in croatian]– institut za geološka istraživanja zagreb, savezni geološki zavod beograd. šimunić, an., najdenovski, j. & pamić, j. (1993): chaotic rock complexes – possible hydrocarbon accumulations in south-western parts of the pannonian basin (republic of croatia).– nafta, 44, 609–616. tari, v. & pamić, j. (1998): geodynamic evolution of the northern dinarides and the southern parts of the pannonian basin.– tectonophysics, 297, 296–281. tatsumi, y. & eggins, s. (1995): subduction zone magmatism.– cambridge, massachusetts, usa, blacwell, 221 p. tomljenović, b., csontos, l., márton, e. & márton, p. (2008): tectonic evolution of the northwestern internal dinarides as constrained by structures and rotation of medvednica mountains, north croatia.– geological society london, special publications, 298, 145–167. tribuzio, r., tiepolo, m. & thirlwall, m.f. (2000): origin of titanian pargasite in gabbroic rocks from the northern apennine ophiolites (italy): insights into the late-magmatic evolution of a mor-type intrusive sequence.– earth and planetary science letters, 176, 281–293. trubelja, f., marching, v., burgath, k-p. & vujović, ž. (1995): origin of the jurassic tethyan ophiolites in bosnia: a geochemical approach to tectonic setting.– geologia croatica, 48, 49–66. ustaszewski, k., schmid, s.m., lugović, b., schuster, r., schaltegger, u., bernoulli, d., hottinger, l., kounov, a., fügenschuh, b. & schefer, s. (2009): late cretaceous intra-oceanic magmatism in the internal dinarides (northern bosnia and herzegovina): implications for the collision of the adriatic and european plates.– lithos, 108, 106–125. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeography, palaeoclimatology palaeoecology, 220, 333–360. vrkljan, m. (1989): eruptive rocks from mt. kalnik.– unpubl. phd thesis, university of zagreb, zagreb, 94 p. (in croatian with english summary). vrkljan, m. & garašić, v. (2004): different geochemical signatures developed in some basic magmatic rocks of mt. kalnik (north croatia).– rudarsko-geološko-naftni zbornik, 16, 65–73. wakabayashi, j. & dilek, y. (2000): spatial and temporal relationships between ophiolites and their metamorphic soles: a test of model of forearc ophiolite genesis.– in: y. dilek, e.m. moore, d. elthon & a. nicolas (eds.): ophiolites and oceanic crust: new insights from field studies and the ocean drilling program: boulder, colorado. the geological society of america, special paper, 349, 53–64. wakabayashi, j. & dilek, y. (2003): what constitutes “emplacement” of an ophiolite?: mechanisms relationship to subduction initiation and formation of metamorphic soles.– in: y. dilek & p.t. robinson (eds.): ophiolites in earth history. geological society london, special publication, 218, 427–447. whatam, s.a. & stern, r.j. (2011): the ‘subduction initiation rule’: a key for linking ophiolites, intra-oceanic forearcs, and subduction initiation.– contributions to mineralogy and petrology, 162, 1031–1045. wilson, m. (1989): igneous petrogenesis.– london, uk, unwin hyman ltd., 466 p. wood, d.a. (1980): the application of a th-hf-ta diagram to problems of tectonomagmatic classification and establishing the nature of crustal contamination of basaltic lavas of the british tertiary volcanic province.– earth and planetary science letters, 50, 11–30. zane, a. & weiss, z. (1998): a procedure for classifying rock-forming chlorites based on microprobe data.– rendiconti lincei scienye fisiche e naturali, 9, 51–56. zindler, a. & hart, s.r. (1986): chemical geodynamics.– annual review of earth and planetary sciences, 14, 439–571. manuscript received july 24, 2014 revised manuscript accepted january 23, 2015 available online february 27, 2015  contribution to the knowledge of cordaites species from the kladno-rakovník basin, middle pennsylvanian (bolsovian), czech republic  zbyněk šimůnek1* and jan haldovský2 1 czech geological survey, klárov 3/131, 118 21 praha 1, czech republic; (zbynek.simunek@geology.cz) 2 modřínová 259, 273 08 pchery – theodor, czech republic doi:10.4154/gc.2015.11 abstract new collections from the spoil piles of the theodor mine in pchery and the schoeller mine in libušín (kladno-rakovník basin, czech republic) yielded a new cordaites species and improved knowledge of the extent of the cuticular variability of the species cordaites wartmannii šimůnek. based on the cuticles, it has been proven that the species cordaites polynervus šimůnek is conspecific with cordaites kladnoensis šimůnek. the new species, cordaites theodorii šimůnek & haldovský sp. nov., established on strongly papillate cuticles, is characterized by the presence of small teeth on the leaf margin. this feature is new for the genus cordaites. the palaeoecological significance of papillae on cordaites cuticles is discussed and is probably an adaptation to living on a peat substrate. comparison of the species cordaites wartmannii šimůnek and cordaites barthelii šimůnek is made. adaxial cuticles of cordaites kladnoensis and cordaites wartmannii are so similar that it is difficult to distinguish these species by means of the adaxial cuticle alone. keywords: cordaites, cuticular analysis, central bohemian basins, carboniferous, bolsovian 1. introduction cordaitaleans are an extinct group of gymnosperm trees and shrubs characterized by large strap-shaped leaves, and woody stems (raymond et al., 2010). their closest living relatives are the modern conifers (rothwell, 1988). the group is divided into families cordaitanthaceae, rufloriaceae and vojnovskyaceae (cleal & thomas, 1995). only the family cordaitanthaceae is widespread in the pennsylvanian and permian of the euramerican realm (jongmans & dijkstra, 1968 and dijkstra & van amerom, 1998). their representatives lived in different habitats from coastal and lowland peat-swamps to intramountain peat swamps (dimichele & phillips, 1994, šimůnek et al., 2009, raymond et al., 2010), to clastic and mineral soils of seasonally dry and dry habitats (falcon-lang, 2003a,b, falcon-lang & bashforth, 2004, dimichele et al., 2010, falcon-lang et al., 2006, 2011, bashforth et al., 2014). the first reference to cordaitaleans from the kladnorakovník basin is by feistmantel (1876). he mentioned cordaites borassifolius (sternberg) unger from the kladno “opuka” locality. however, he understood this species in a very broad sense and identified it from all geologia croaticageologia croatica geologia croatica 68/2 93–111 2 figs. 1 tab. 9 pls. zagreb 2015 geologia croatica 68/2geologia croatica 94 the basins of the bohemian massif with age ranges from the beginning of the westphalian (bashkirian) to the permian. the oldest mining area in the kladno region was in the vrapice surroundings in the 18th and 19th century. maybe, feistmantel (1876) sourced his material from these mine workings, because coal mines, from which the cordaitalean specimens used in this paper originated were in operation much later (pchery, theodor mine – 1900-1935; libušín, schoeller mine – 1902-2002; tuchlovice, nosek mine – 1942-2002). cordaitaleans were neglected in the czech literature for a long time as stratigraphically uninteresting plants. for instance, němejc (1936a, 1940, 1947) published monographs of different plant groups (alethopterids, pecopterids, lepidodendrids), where the libušín, schoeller mine locality is mentioned, but he was never interested in cordaitaleans. for all that, florin (1931) published a drawing of the abaxial cuticle of cordaites sp. 1 from the rakovník locality in the kladno-rakovník basin, and it seems figure 1: a – map of the czech republic showing the permocarboniferous basins. b – kladno-rakovník basin with localities. c – stratigraphy of the central bohemian permo-carboniferous fill and detail of the radnice member showing the stratigraphic position of the localities (arrow). (modified from opluštil et al., 2007 and 2014). šimůnek and haldovský: contribution to the knowledge of cordaites species from the kladno-rakovník basin, middle pennsylvanian, czech republic geologia croatica 95 that this species is different to all 30 later described cordaitalean species (šimůnek, 2007), classified by means of their cuticles. five of those species occur in the kladno region. their leaves were collected by the first author (zš) from the tuchlovice and libušín localities from the 1980s until the closure of the mines. the second author (jh) put together a large collection from the spoil pile of the theodor mine, at the pchery locality during recent years. maceration of the new samples provided new data which required a subsequent revision of cordaitalean cuticles. the biostratigraphy of the radnice member has been known since the beginning of the 20th century, when němejc (1932) placed the radnice member in the upper westphalian c (bolsovian). the radnice member is assigned to the paripteris linguaefolia zone of wagner (1984). 2. geological setting the kladno-rakovník basin is a part of the central and western bohemian complex, which is characterised by a stratigraphic range from the middle westphalian (bolsovian) to the end of the stephanian (pešek 1994) and the lower part of the permian (zajíc, 2012). sedimentary fill in this complex is subdivided into four formations (fig. 1) based on alternating red (coal-barren) and grey (coal-bearing) strata (weithofer, 1902). the radnice member (bolsovian) comprises the most important coal-bearing strata of the basins in central and western bohemia. sediments of this unit are interpreted as the fill of river valleys that either were incised into the basement or with tectonically driven valley margins (opluštil 2005a). in the kladno-rakovník basin, coal seams are represented by the lower and upper radnice coals, which together comprise the radnice group of seams. the lower radnice coal is usually up to 1 m thick. the upper radnice coal is the most important seam of the basin being locally up to 8 m thick. both coal seams are separated by the volcanic whetstone horizon, which tends to be a few metres thick. this horizon consists of an approximately 60 cm thick pale yellow fossiliferous tuff bed (the “bělka”), followed by poorlyto well-laminated tuffitic claystone and mudstone (the “whetstone”). 3. material and methods the majority of flora collected in the libušín, pchery and tuchlovice localities comes from the tuffaceous partings called “opuka”. the cordaitalean remains were collected predominantly in the 20 cm thick parting called “velká opuka” that occurs in the lower third from the footwall of the upper radnice (main kladno) coal seam (opluštil, 2005a,b and opluštil et al., 2007). the material used in this study is stored in the czech geological survey, prague and comes from the following localities: tuchlovice, nosek mine (holotype of cordaites polynervus šimůnek, no. zš 247), libušín, schoeller mine (holotype of cordaites wartmannii, no. zš 246 and additional specimens zš 302–306), pchery, theodor mine (holotype of cordaites theodorii šimůnek & haldovský sp. nov., and specimens of cordaites wartmannii šimůnek, zš 350; and cordaites kladnoensis, zš 358a,b). from these samples, cuticular slides no. 113/1-2, 182/1-3, 395/1-8, 518/1-13 and 543/1-4 were prepared by the method described by kerp (1990), krings & kerp (1997) and kerp & krings (1999). coalified fragments of leaves were separated from the rock by means of a needle or hydrofluoric acid (hf). these fragments were bleached in schulze’s reagent (40% hno3 with crystals of kclo3) for 3–18 hours (depending on preservation). after treatment in schulze’s reagent, cuticles were washed in water, subsequently immersed in 2% or 10% potassium hydroxide (koh) and finally rinsed in distilled water. some cuticles were stained with safranin, bismarck brown, malachite green or neutral red (krings, 2000) for 1 to 2 hours to accentuate the anticlinal walls and stomata. before embedding in glycerine-gelatine slides, the cuticles were dehydrated in pure glycerine. the remaining cuticular fragments were affixed to metal stubs for observation under a cam scan cs 3200 scanning electron microscope at the czech geological survey, prague. stomatal index (si) is calculated for specimens analysed here. it was first employed by salisbury (1927) and describes the number of stomata expressed as a percentage of the total number of cells per unit area: si = 100 × total number of stomata / (total number of stomata + total number of epidermal cells). stomatal density represents the number of stomata per unit area, usually the number of stomata per 1 mm2. the minimum area for calculation of stomatal density is 0.3 mm2 (poole & kürschner, 1999). 4. systematic palaeobotany order cordaitanthales meyen, 1984 family cordaitanthaceae meyen, 1984 genus cordaites unger, 1850 4.1. cordaites wartmannii šimůnek emend. nov. (fig. 2a, b, g–h, pl. 1a–d, pl. 2, 3, 4, 5, pl. 7g–h) 2007 cordaites wartmannii šimůnek, p. 147–148, text-fig. 38, pl. 3, fig. 15, pl. 41, figs 5, 6, pls 42, 43, figs 1–2. emended diagnosis (šimůnek, 2007, p. 147): leaves revolute, adaxial cuticle composed of oblong cells, cells of dark stomatal band tetragonal to pentagonal shape, subsidiary cells oval, lateral subsidiary cells semicircular. abaxial cuticle papillate with oblong to trapezoidal cells, stomata in stomatiferous bands, polar subsidiary cells circular to oval, lateral subsidiary cells elongated, tetragonal to oval. description: the holotype is the narrowest leaf fragment of this species – 18 mm wide (pl. 1a). the largest leaf fragments are up to 190 mm long and the widest 45 mm wide. the leaf margins are nearly parallel or somewhat divergent (narrow leaves) and revolute (inrolled toward the lower surface) in some cases. such leaves may seem to be as little as only 20 mm wide. the veins have a small furrow geologia croatica 68/2geologia croatica 96 in the middle, so they look like double veins. the vein density is low – 10 to 16 prominent veins per cm. exceptionally one, but usually 2–3 narrow strips of sclerotic strands alternate with each vein. the leaves have stomata on both sides (amphistomatic). cuticular characteristics: it is not necessary to repeat the whole description from šimůnek (2007, p. 147). only new observations based on new material from the libušín and pchery localities will be mentioned. the comparison of cuticular characteristics is in table 1. adaxial cuticle (figs 2a–b, pls 2a–c, 3a–d, 4g–l): dark stomatal bands, 60–120 μm wide, are formed by one or two incomplete stomatal rows. non-stomatiferous (costal) bands are formed by ordinary cells, they are usually of uneven width and can be 50–200 μm wide (depending on the specimen). the costal cells (in non-stomatiferous bands) are tetragonal, mostly oblong, 40–100 μm long and 16–30 μm wide. the cells of the dark (stomatiferous) bands are usually smaller. the stomata in dark stomatiferous (intercostal) bands are unevenly spaced. they can be up to 150 μm apart but sometimes touch. the stomatal complex is formed by two guard cells and two lateral and two polar subsidiary cells. on better preserved cuticles, it is evident that only polar subsidiary cells are circular or oval, whereas lateral subsidiary cells tend to be more reniform. specimens from the pchery, theodor mine show prominent proximal papillae growing from the lateral subsidiary cells towards the stoma (pl. 4k, l). the stomatal density is 54–68 stomata per mm2 and the stomatal index varies between 5 and 7. abaxial cuticle (figs. 2e–h, pls. 2d–f, 3e–g, 4a–f, 5, 7g–h): the stomata are arranged into stomatiferous and non-stomatiferous bands. depending on specimens, their width is very variable, from 150 μm to 450 μm (pl. 3e, f) in the stomatiferous bands, and 100–350 μm in the non-stomatiferous bands. because all the stomatiferous bands almost entirely comprise stomatal complexes, they markedly differ from the non-stomatiferous bands. in certain planes of focus, small flat papillae are visible on cells of the stomatiferous and non-stomatiferous bands (pls. 2d-f, 3e, f). the stomatal rows are more or less regular within the stomatal band, but a lateral subsidiary cell is usually shared by two stomatal complexes, so the course of the stomatal rows is not as regular as in the species forming regular rows. the cells of the non-stomatiferous bands are tetragonal, oblong to trapezoidal, 45–95 μm long and 12–25 μm wide. in the holotype, lateral and polar subsidiary cells are elongated and of the same dimensions (pl. 2g, f). however, cuticles from another specimen (pl. 3f, g) show that polar subsidiary cells can be very short, circular or oval, 15–30 μm long and 10–25 μm wide. sometimes polar cells are elongate as lateral cells 30–60 μm long. the anticlinal walls of these cells are convex, so they differ from the cells of the non-stomatiferous band. a lateral subsidiary cell is usually shared by two stomatal complexes. the stomatal density is 400 to 600 stomata. per mm2 depending, on how wide the stomatiferous and non-stomatiferous bands are. this factor also influences the stomatal index (si) with ranges from 12 to 23. in the non-stomatiferous bands, circular, strongly cutinised structures occur on periclinal cell walls (pls. 3e, f, 6i). their function is not known. another cuticle assigned to this species (fig. 2h, pl. 7g, h) displays oval polar subsidiary cells, whereas the stomatal slit and the lateral subsidiary cells are not prominent. it is probably a more disorganized cuticle of cordaites wartmannii where even papillae are not preserved. remarks: cordaites wartmannii was compared with cordaites sp. of wartmann (1969) from the bolsovian figure 2: comparison of the described cordaitalean stomatal types from the kladno-rakovník basin. scale bar = 50 mm . a–d. adaxial cuticles that have similar pattern; stomata in dark stomatiferous bands; a–b. cordaites wartmannii šimůnek, libušín locality, a – holotype, slide 113/1 (pl. 2c), b – type with circular to oval polar subsidiary cells, slide 395/5 (pl. 3b); c–d. cordaites kladnoensis šimůnek, c – tuchlovice locality, holotype of “cordaites polynervus”, slide 182/1, (pl. 8d), d – pchery locality, slide 543/4 (pl. 9c), small rounded objects are damage to cuticles due to bacterial or fungal infection (maybe post mortum). e–j. abaxial cuticles; e–h. cordaites wartmannii šimůnek; e–f. libušín locality, e – holotype, slide 113/1, with elongated polar subsidiary cells and many flat papillae, f – a specimen with more or less circular polar subsidiary cells, resembling the stephanian cordaites barthelii šimůnek. slide 395/5 (pl. 3a); g–h. pchery locality, cuticles with rounded polar subsidiary cells as in fig. 2f, g – slide 518/6 (pl. 5g), h – this cuticle is a somewhat disorganized. slide 518/2 (fig. 9h); i – cordaites theodorii haldovský & šimůnek sp. nov. pchery locality. cuticle with many dark, prominent papillae. slide 518/2 (pl. 7c); j – cordaites kladnoensis šimůnek, holotype of “cordaites polynervus” tuchlovice locality, slide 182/1 (pl. 8e). guard cells are sunken below strongly cutinised crypt. triangular cutin thickenings and projections are in the cell corners. šimůnek and haldovský: contribution to the knowledge of cordaites species from the kladno-rakovník basin, middle pennsylvanian, czech republic geologia croatica 97 ta bl e 1: c om pa ris on o f c or da ite s s pe ci es fr om th e ra dn ic e m em be r o f t he k la dn ora ko vn ík b as in a nd c or da ite s b ar th el ii fro m th e st ep ha ni an o f t he k rk on oš e pi ed m on t b as in . re fe re nc e ši m ů n ek (2 00 7) ši m ů n ek (2 00 7) ši m ů n ek (2 00 7) , t hi s p ap er th is p ap er ši m ů n ek (2 01 4) sp ec ie s co rd ai te s k la dn oe ns is co rd ai te s p ol yn er vu s* co rd ai te s w ar tm an ni i co rd ai te s t he od or ii co rd ai te s b ar th el ii lo ca lit y tu ch lo vi ce , p ch er y tu ch lo vi ce li bu ší n, p ch er y pc he ry sy ře no v le af le ng th (m m ) >2 30 >1 30 >1 50 ? >9 0 le af w id th (m m ) 30 –9 0 25 18 –4 5 ? 21 –2 9 n o. o f t ru e ve in s p er 1 m m 10 –2 2 10 –1 2 10 –6 ? 25 n o. o f s cl er ot ic st ra nd s b et w ee n ve in s (4 –7 )(2 –3 ) d ep en ce o n po si tio n an d si de o f t he le af 4– 6 (1 ) 2 –3 ? ? ( ve ry fi ne ) le af m ar gi n sm oo th sm oo th sm oo th d en ta te sm oo th le av es am ph is to m at ic am ph is to m at ic am ph is to m at ic h yp os to m at ic am ph is to m at ic adaxial cuticle ce ll sh ap e of st om at al ro w s o bl on g te tr ag on al to o va l te tr a to p en ta go na l, ne ar ly is od ia m et ric – o bl on g or e lo ng at ed h ex ag on al si ze o f s to m at ife ro us c el ls (µ m ) (4 0– 70 ) x (1 0– 25 ) (2 5– 50 ) x (1 0– 30 ) (2 5– 60 ) x (1 0– 22 )   (4 5– 80 x (2 0– 30 ) ce ll sh ap e of n on -s to m at ife ro us b an ds sq ua re to o bl on g re ct an gu la r – o bl on g te tr ag on al – o bl on g st ro ng ly p ap ila te , l on gi tu di na lly te tr ag on al o bl on g or e lo ng at ed h ex ag on al si ze o f n on -s to m at ife ro us c el ls (µ m ) (3 0– 60 ) x (1 0– 20 ) (3 0– 70 ) x (2 5– 35 ) (4 0– 10 0) x (1 6– 30 ) (4 0– 15 0) x (8 –1 2) (4 5– 80 x (2 0– 30 ) st om at a in d ar k ba nd s in d ar k ba nd s in d ar k ba nd s – in st om at al ro w s st om at al d en si ty o n 1 m m 2 30 –4 5 40 –4 5 54 –6 8 – 40 st om at al in de x 3– 3. 5 (in cl ud in g no nst om at ife ro us ba nd ) ab ou t 1 0 in d ar k ba nd 5– 7 – 3. 8 si ze o f 2 g ua rd c el ls (µ m )   (2 5– 30 ) x (1 5– 20 ) (1 8– 22 ) x (1 0– 13 ) – (1 2– 20 ) x (7 –1 0) si ze o f s to m at al c om pl ex (µ m )   (6 0– 75 ) x (9 0– 12 5) (4 5– 55 ) x (6 0– 80 ) – (7 5– 95 ) x (3 5– 45 ) po la r s ub si di ar y ce lls – n um be r 2– 3 2 2 (3 ) – 2 sh ap e o va l o bl on g to o va l tr ap ez oi da l t o ov al – po ly go na l ( el on ga te d) si ze in µ m 10 –1 5 in d ia m et er (3 5– 52 ) x (2 5– 30 ) 20 –3 2 (in d ia m et er ) – (1 5– 45 ) x (1 0– 18 ) la te ra l s ub si di ar y ce lls – n um be r 2– 3 2– 4 2 (3 ) – 2 sh ap e o rb ic ul at e o bl on g to o va l tr ap ez oi da l t o ov al – po ly go na l ( ob lo ng to h ex ag on al ) si ze v µ m 11 –1 5 in th e di am et er (2 5– 60 ) x (2 5– 30 ) 20 –3 2 (v p rů m ěr u) – (3 8– 55 ) x (1 0– 25 ) abaxial cuticle d iff er en tia tio n of c el ls st om at ife ro us b an d (1 50 –2 50 µ m ); no nst om at ife ro us b an d (1 50 –2 50 µ m ) po or ly p re se rv ed st om at ife ro us b an d (1 50 –4 50 µ m ); no nst om at ife ro us b an d (1 00 –3 50 µ m ) st om at a in st om at al ro w s st om at ife ro us b an d (4 50 –5 50 µ m ); no nst om at ife ro us b an d (1 00 –1 50 µ m ) ce ll sh ap e of st om at fif er ou s b an d o va l t o irr eg ul ar ly p en ta go na l ? te tr ag on al , o bl on g to tr ap ez oi da l te tr ag on al pe nt ag on al to h ep ta go na l ( m os tly he xa go na l) ce ll si ze o f s to m at ife ro us b an d (µ m ) (2 5– 50 ) x (1 2– 25 ) ? (3 0– 60 ) x (8 –1 8)   (3 0– 70 ) x (1 0– 18 ) an tic lin al w al ls ro un de d ? st ra ig ht to b en t   st ra ig ht to b en t ce ll or ie nt at io n of st om at ife ro us b an d ra nd om ? pa ra lle l t o ve in s   pa ra lle l t o ve in s ce ll sh ap e of n on -s to m at ife ro us b an d lo ng itu di na lly te tr ag on al re ct an gu la r – o bl on g o bl on g to tr ap ez oi da l, ci rc ul ar to o va l lo ng itu di na lly te tr ag on al o bl on g ce ll si ze o f n on -s to m at ife ro us b an d (µ m ) (3 0– 80 ) x (1 0– 25 ) (3 0– 75 ) x (2 0– 30 ) (4 5– 95 ) x (1 2– 25 ) (3 5– 13 0) x (8 –2 0) (5 0– 11 0) x (1 0– 22 ) st om at a in th e st om at ife ro us b an ds           – d is tr ib ut io n in st om at ife ro us b an ds in st om at ife ro us b an ds in st om at ife ro us b an ds in st om at al ro w s in st om at ife ro us b an ds st om at al d en si ty o n 1 m m 2 35 0– 40 0 (in st om at ife ro us b an d) ? 40 0 (5 30 –6 00 in st om at ife ro us b an d) 18 0– 24 0 60 0 (7 75 in st om at ife ro us b an d) st om at al in de x 13 –1 5 (in st om at ife ro us b an d) ? 12 (1 5– 23 in st om at ife ro us b an d) 11 –1 3 20 (2 2 in st om at ife ro us b an d) g ua rd c el l p ai r s ha pe el lip tic al ? el lip tic al el lip tic al el lip tic al g ua rd c el l p ai r s iz e (µ m ) (2 0– 30 ) x (1 0– 15 ) ? (2 5– 30 ) x (8 –1 4) (2 5– 30 ) x (8 –1 4) (1 6– 25 ) x (8 –1 4) st om at al c om pl ex si ze (µ m ) (5 0– 65 ) x (4 0– 50 ) ? (5 2– 65 ) x (3 2– 40 ) (6 0– 75 ) x (3 2– 42 ) (5 5– 70 ) x (3 2– 40 ) po la r s ub si di ar y ce lls nu m be r 2 ? 2 2 2 sh ap e sa m e as o rd in ar y ce lls ? o bl on g, o va l, ci rc ul ar o bl on g tr ig on al , r ho m bo id al , o va l. si ze in µ m – ? [1 5– 30 (6 0) ] x (1 0– 25 ) (3 0– 45 ) x (8 –1 2) (2 0– 30 ) x (1 0– 20 ) la te ra l s ub si di ar y ce lls – n um be r 2– 3 ? 2– 3 2 2 sh ap e sa m e as o rd in ar y ce lls ? u su al ly o bl on g, ra re ly re ni fo rm o bl on g pe nt ag on al to h ep ta go na l ( m os tly he xa go na l) si ze in µ m – ? (3 0– 60 ) x (1 0– 25 ) (3 0– 60 ) x (1 0– 25 ) (3 0– 70 ) x (1 0– 18 ) o ut er st om at al c av ity st ro ng ly c ut in iz ed a bo ve su nk en g ua rd ce lls ? st ro ng er c ut in iz at io n or p re se nc e of pr ox im al p ap ill ae fr om la te ra l su bs id ia ry c el ls st ro ng ly c ut in is ed p op ill ae to w ar ds th e st om a st ro ng er c ut in iz at io n or p re se nc e of pr ox im al p ap ill ae fr om la te ra l su bs id ia ry c el ls * o rig in al d es cr ip tio n (š im ů n ek , 2 00 7) , h er e as si gn ed to c or da ite s k la dn oe ns is geologia croatica 68/2geologia croatica 98 of the saar region (germany) by šimůnek (2007) based on the presence of papillae in both species. however, cordaites sp. of wartmann (1969) has much larger and more prominent papillae than cordaites wartmannii šimůnek. in this feature, cordaites sp. of wartmann (1969) bears more resemblance to cordaites theodorii šimůnek & haldovský sp. nov., which also has many strongly cutinised papillae. because papillae occur in several species, to date it has been difficult to decide to which species wartmann’s cordaites sp. belongs. the most similar species to cordaites wartmannii šimůnek is cordaites barthelii šimůnek, 2014 from the stephanian b of the krkonoše piedmont basin. the abaxial cuticles in particular of both species are very similar. stomata of both species form wide stomatiferous bands, up to 550 mm wide, and are arranged in a stomatal row. cordaites barthelii has polar subsidiary cells common to two stomatal complexes, whereas cordaites wartmannii has polar and usually also lateral cells common to two stomatal complexes. cordaites wartmannii differs from cordaites barthelii by the presence of small papillae, visible in certain planes of focus on the light microscope. small “holes” in the centre of certain cells of the non-stomatiferous bands occur in both cordaites barthelii and c. wartmannii. the function of these holes is unknown. it is possible that these holes were the result of distortion of the cuticle but, as they also occur in cordaites wartmannii, it is evident that they are not an artificial feature and the cracks may be related to differential cutinisation of certain cells and their subsequent torsion. the similarities provide further evidence that cordaites barthelii and cordaites wartmannii are related species. the adaxial cuticle of cordaites barthelii and cordaites wartmannii have stomata in rare stomatiferous bands. the stomatiferous bands of cordaites barthelii are not as dark coloured as in cordaites wartmannii. also, the shape of the subsidiary cells of both species differs. polar subsidiary cells of cordaites wartmannii are circular to oval, whereas those of cordaites barthelii are elongated and usually oblong; lateral subsidiary cells of cordaites wartmannii are broad reniform, whereas those of cordaites barthelii are narrow and oblong. furthermore, the venation density of both species differs. cordaites wartmannii has 10–16 veins per 1 cm of the leaf, whereas cordaites barthelii has about 25 veins per 1 cm of the leaf. cordaites kladnoensis šimunek (2007) is another species similar to cordaites wartmannii. both have stomata of the adaxial cuticle arranged in dark stomatiferous bands. in the case of cordaites kladnoensis, the distances between stomatiferous bands are more regular than in cordaites wartmannii. both species have similar vein densities: cordaites kladnoensis has 10–22 veins per 1cm, and cordaites wartmannii has 10–16 veins per 1 cm of the leaf. however, the abaxial cuticles of these species are quite different. guard cells of cordaites kladnoensis are sunken and covered by a strongly cutinised crypt. subsidiary cells are oval with strongly cutinised corners; in contrast, cordaites wartmannii does not have such a crypt, but has at most two proximal papillae from the lateral subsidiary cells. the subsidiary cells are narrower and longer than in cordaites kladnoensis, and only the polar subsidiary cells can be rounded in cordaites wartmannii. 4.2. cordaites theodorii šimůnek & haldovský sp. nov. (fig. 2i, pls. 6. and 7a–f) derivation of name: after the theodor mine, which is the type locality of this species. holotype: designated here on pl. 1e, is stored in the czech geological survey under the no. zš 350, slides no. 518/1–13 type locality: pchery, theodor mine, kladno-rakovník basin, czech republic. type horizon: tuffaceous parting (opuka) of the upper radnice coal seam, radnice group of coals, radnice member, kladno formation, bolsovian, middle pennsylvanian. material: only one sample (holotype). diagnosis: very small and rare teeth on the leaf border, hypostomatic leaves, strongly papillate cells on abaxial and adaxial epidermis. adaxial epidermis: parallel oriented, elongate tetragonal cells. abaxial epidermis: elongated cells, stomata in rows. description: much of the macromorphology and venation of the leaves is uncertain, because cuticles of cordaites wartmannii were also obtained from the same sample, and because the adpressions on pl. 1e, f, g resemble other cordaites wartmannii leaves. we know for certain that the leaf margin was dentate. the distances between the teeth were 0.3–0.5 mm (pl. 6a), and teeth were acroscopically oriented and 30–40 μm long (pl. 6b). we can speculate, however, that the leaf surface had little relief, because the cuticular structure is uniformly flat. adaxial cuticle (pl. 6c-f): it is not possible to differentiate costal and intercostal bands. the cells are tetragonal, elongated, very narrow and oriented parallel to veins. they are 40–150 μm long and 8–12 μm wide. each cell bears many small, strongly cutinised papillae, 3–5 μm in diameter and visible as black spots. abaxial cuticle (figs. 2i, pl. 7a–f): the cells of the abaxial cuticle resemble the cells of the adaxial cuticle. they are strongly papillate, with an elongated tetragonal shape, 35–130 μm long and 8–20 μm wide (pl. 7e). stomata are arranged into stomatal rows. polar and lateral subsidiary cells are oblong, similar to normal epidermal cells. a row of papillae runs from one end to another in the middle of the cell. in addition, proximal papillae point into the stoma centre, above the sunken guard cells. the stomatal complex (including 4 subsidiary cells) is 60–75 μm long and 32–42 μm wide. stomatal density and stomatal index were calculated from 3 measurements. stomatal density varies from 180 to 240 stomata per mm2; stomatal index varies from 11.1 to 12.9. some inaccuracy could have been caused by the small area used for these calculations. remarks: this species is strongly papillate and differs from all other known species of cordaites in being hypostomatic and in having a dentate margin. it is also a distinct species based on the cuticular micromorphology. šimůnek and haldovský: contribution to the knowledge of cordaites species from the kladno-rakovník basin, middle pennsylvanian, czech republic geologia croatica 99 4.3. cordaites kladnoensis šimůnek emend nov. (figs. 2c, d, j; pl. 8a–i; pl. 8j-l; pl. 9) 2007 cordaites kladnoensis šimůnek, p. 143–144, text-figs. 36a–i, pl. 3, fig. 14, pl. 38, figs. 2–6, pls. 39, 40, figs. 1–3. 2007 cordaites polynervus šimůnek, p. 148–149, text-figs. 39a–f, pl. 43, figs. 3–7, pl. 44, figs. 1–3 emended diagnosis (šimůnek, 2007, p. 143): amphistomatic, large leaves with sparse venation, 2–7 thin sclerenchymatous bands alternate with each thick vein. cells of adaxial cuticle oblong, stomata in infrequent stomatal rows, subsidiary cells circular to oval. proximal papillae on lateral subsidiary cells. cells of abaxial cuticle oval or irregularly pentagonal, stomata in stomatiferous bands without discernible stomatal rows. material: tuchlovice, nosek mine, pchery, theodor mine, kladno-rakovník basin. czech geological survey, prague, inv. no. zš 247, coll. z. šimůnek. radnice member, bolsovian. description: here we redescribe the specimen selected as a holotype of cordaites polynervus and the specimen from pchery, theodor mine. the holotype from tuchlovice is a leaf fragment 25 mm wide and about 130 mm long with nearly parallel margins. the leaf surface relief is flat. there are 10–12 veins per 1 cm of the leaf surface. on the impression (pl. 8i, right), positive and negative relief of vascular and sclerotic bundles are visible. usually one to two sclerotic bundles alternate with one true vein. on the phytoleim (thin carbon layer on a plant compression) (pl. 8i, left), 4–6 very fine strips occur between two veins, probably representing stomatiferous bands (or non-stomatiferous bands?). a similar pattern is found on the specimen from pchery (pl. 1h, inv. no. zš 358a). the leaf fragment is 160 mm long and 23 mm wide with non-parallel margins, but, as the leaf margins are revolute, the true leaf width was probably 33 mm. 4–6 very fine sclerotic bundles alternate with each true vein (pl. 1i), and the same pattern is seen on the on the imprint (pl. 1j, right). the imprint itself (pl. 1j, left) shows more prominent true veins separated by one or two sclerotic strips. the leaves are amphistomatic. adaxial cuticle of the tuchlovice specimen (figs. 2c, pl. 8a–d): the dark stomatiferous (intercostal) bands are 80–140 μm wide, whereas non-stomatiferous (costal) bands are 120– 200 μm wide. the ordinary cells are tetragonal to oval, 25–50 μm long and 10–30 μm wide. the costal cells are larger than the intercostal cells; they are rectangular, usually oblong, 30– 70 μm long and 25–35 μm wide. the stomatal complexes are in irregular distances from each other within dark stomatiferous bands that are formed by single or double stomatal rows oriented parallel to the veins. sunken guard cells are usually surrounded by 4 subsidiary cells that slightly differ from the ordinary epidermal cells of the dark bands – polar cells are square to oblong; lateral cells are oblong to reniform. the stomatal complexes (including subsidiary cells) are 90–125 μm long and 60–75 μm wide. the stomatal density is about 40–45 stomata per 1 mm2 on the leaf blade. the stomatal index is 4.2 and for the dark bands about 10. adaxial cuticle of the theodor mine specimen (figs. 2d, pls. 8j–l, 9): the cells are differentiated into dark stomatiferous bands and non-stomatiferous bands (pls. 8j–l, 9). the stomata are relatively sparse in the dark bands. the cells are usually of oblong shape. the cells of the non-stomatiferous bands are longer, 30–70 μm long and 12–18 μm wide, whereas those of the dark stomatiferous bands are only 25–35 μm long and 15–20 μm wide. the stomata are relatively rare and are dispersed within the dark bands. the stomatal complexes are formed by 6 cells: two guard cells, two lateral and two polar subsidiary cells. lateral subsidiary cells are usually oblong or reniform and polar subsidiary cells are oblong to oval. guard cells are sunken and partly covered by proximal papillae growing from lateral subsidiary cells (figs. 2d, pl. 9c). the stomatal density is 45 stomata per mm2 (95 in the stomatal band) and the stomatal index is 3.2 (6 in the stomatal band). abaxial cuticle of the tuchlovice specimen (fig. 2j, pl. 8e–h): šimůnek (2007, p. 149) considered a poorly preserved cuticle as an abaxial one and described it as cordaites polynervus (šimůnek, 2007, pl. 43, figs. 3–6 and pl. 44 figs. 1–2). in slide 182/1, the holotype of cordaites polynervus, a cuticular fragment of known abaxial cuticle has been discovered that proves the identity of cordaites polynervus as cordaites kladnoensis, thus allowing these synonymy of these two species to be recognised. the cells are differentiated into stomatiferous (intercostal) and non-stomatiferous (costal) bands, both of which vary in width between 150–200 μm (pl. 8f). the cells of the stomatiferous bands are oval to irregularly pentagonal, 25–50 μm long and 12–25 μm wide. the anticlinal walls are rounded. the costal (non-stomatiferous) cells are elongated and tetragonal, 30–80 μm long and 10–25 μm wide. the stomata are not prominent and they occur in stomatiferous bands with poorly defined stomatal rows. the sunken guard cells are dark, convex and oblong (figs. 2j, pl. 8e, h). the corners and anticlinal walls of cells are strongly cutinised, so it is sometimes difficult to distinguish cutinisation from stomata. the stomatal complexes (including subsidiary cells) are 50–65 μm long and 40–50 μm wide. the subsidiary cells, 4–5 per stoma, are of the same shape as the ordinary epidermal cells, usually oblong to oval with convex anticlinal walls. the stomatal density is about 280 stomata per mm2, and about 570 stomata per mm2 in the stomatiferous band, which, is more than for cordaites kladnoensis as described by šimůnek (2007). stomatal index is 15 for the whole leaf surface and 17 for the stomatiferous band. the abaxial cuticle of this species from the theodor mine was not preserved. remarks: comparison of cordaites kladnoensis with cordaites wartmanniï was mentioned in the description of the latter species. the abaxial cuticle of two other species is similar to cordaites kladnoensis. adaxial and abaxial cuticles of cordaites principalis (germar) geinitz morphotype 5 of zodrow et al. (2000) are very similar to the abaxial cuticle of cordaites kladnoensis. the cell corners geologia croatica 68/2geologia croatica 100 are strongly cutinised in the stomatiferous band and a strongly cutinised crypt is present above the guard cells in cordaites kladnoensis abaxial cuticle. essentially, the same pattern as in cordaites kladnoensis occurs in cordaites radcicensis šimůnek (2008), which also has sunken stomata on the abaxial cuticle that are covered by a strongly cutinised crypt. the cell corners are strongly cutinised with projections that fill the intercellular space. the adaxial cuticles of cordaites radcicensis and cordaites kladnoensis both have stomata in dark stomatiferous bands. cordaites radcicensis has a lower stomatal density (only 8–11 stomata per 1 mm2) than cordaites kladnoensis, which has 30–45 stomata per 1 mm2 in the adaxial cuticle. cordaites principalis (germar) geinitz morphotype 5 of zodrow et al. (2000) occurs in the bolsovian of the maritimes basin, canada, whereas cordaites radcicensis occurs in the asturian of the plzeň basin, czech republic. 5. discussion the flora of the radnice member in the studied localities includes about 90 species that represent 50 to 60 “natural” species of lycopsids, sphenopsids, ferns, progymnosperms, pteridosperms and cordaitaleans that are represented mostly by trees, bushes, lianas and creeping forms. the diversity of flora indicates a wet tropical forest. practically all cordaitalean remains come from tuffaceous partings (“opuky”) of the upper radnice coal seam, and in particular from the velká opuka (fig. 1). the topography of the coal-bearing strata was formed by wide valleys up to 2 km wide and up to 10 km long (opluštil, 2005a,b). the altitude is estimated to be 900– 1200 m (opluštil, 2005b). plant assemblages of the tuffaceous partings (“opuky”) comprise both peat-forming plants that were buried in place (opluštil et al., 2007), and partly also non-peat-forming plants that were transported to the place of deposition from non-peat accumulating areas and also from valley slopes. the marginal parts of these coal deposits are enriched by non-peat-forming flora (progymnosperms, some cordaitaleans and pteridosperms). these elements disappear towards the valley centre. cordaitaleans were very common in the tuchlovice, nosek mine locality. as they were commonly found together with a primitive lycopsid omphalophloios feistmantelii (feistmantel) bek et al. (2015), it is supposed that these cordaitaleans belonged to peat-forming plants. omphalophloios feistmantelii (feitmantel) bek et al. is a major producer of densosporites and it grew in the “densospore phase”, which probably represents wet conditions in the peat swamp, when domed peat suffered nutrient deficiency and only well adapted plants could grow there (dimichele, pers. com.). cordaitalean remains were locally common, up to 10 to 20 % of the assemblage in the velká opuka parting in both the tuchlovice and theodor mines. this is in concordance with the observation of raymond et al. (2010), where they found a coal plant assemblage comprising 29–81 % cordaitaleans in lowland and coastal peat-swamp settings in iowa, usa. a similar situation occurs in kentucky and tennessee, where cordaitaleans form 33–40 % of a plant assemblage of the same or slightly younger age – middle to upper bolsovian. american cordaitalean-dominated assemblages are accompanied by a primitive lycopsid chaloneria pigg & rothwell (raymond et al., 2010), whereas it seems that omphalophloios white prevails with cordaitaleans in the czech assemblages. the libušín, schoeller mine locality is an exception. cordaitaleans, represented by only one species, cordaites wartmannii, were very rare here; extrabasinal and other “exotic” elements are also rare or absent. the cuticles of cordaites wartmannii were newly discovered (not published) in the dispersed cuticular spectrum from coal from the wanieck coal mine, srby locality (near tuchlovice). the study of dispersed cordaitalean cuticles from the coal (šimůnek & florjan, 2013) revealed that cuticles bear considerably more papillae than do cuticles prepared from compression/impression specimens. papillae have been described on cordaitalean cuticles by many authors: cordaites sp types 2 and 3 (barthel, 1962), cordaites sp. types 6 and 7 from the permian schweinsdorf coal seam in the döhlen basin, germany (barthel, 1964); cordaites sp. from the bolsovian of the saar region of germany (wartmann, 1969); and cordaites neimengensis from the lower permian of inner mongolia, china (liu et al., 1998). this could be further evidence that papillate cordaites wartmannii is a peat-forming plant. the reasonable interpretation of the presence of the papillae on plants growing in tropical rain forest was given by cleal and shute (2012). they argue that papillae in medullosan pteridosperms could protect the stomata from water ingress into the stomatal pore. the papillae in the cordaitaleans could have a similar function. cordaites theodorii from the pchery locality is also supposed to be a peat-forming plant because its cuticles are strongly papillate and it was found on the same specimen together with the previously mentioned cordaites wartmannii. seven of the nine abaxial cuticular species of the genus cordaabaxicutis šimůnek & florjan, 2013 were papillate. these species came from different strata and localities of the upper silesia basin (poland). in contrast, only a few of the c. 30 species from the bohemian massif that were prepared from compressions bear papillae on the abaxial cuticle (šimůnek, 2007). the evidence thus suggests that cordaitaleans living in saturated peat substrates tended to have more papillate epidermal surfaces. however, the function of these papillae remains unknown (šimunek & florjan, 2013). a different situation occurs in cordaites kladnoensis. it is not papillate and resembles cordaites radcicensis, which comes from mudstones of the cantabrian plzeň basin, czech republic, where coal was not developed. if we suppose a similar habitat, it maybe grew in the marginal parts of the swamp. we can deduce the original habitat of cordaitaleans from the facies in which they are preserved. bashforth et al. (2014) described a flora from different rocks of a mega fan structure of langsettian age in new brunswick, canada. the predominance of cordaitalean, mostly in coarse deposits, suggested to these authors that these plants lived in better-drain ed substrates and also on river banks. the rooting system of these huge trees enabled them to live in “dry” soils, where the wašimůnek and haldovský: contribution to the knowledge of cordaites species from the kladno-rakovník basin, middle pennsylvanian, czech republic geologia croatica 101 ter table was low. alternatively, smaller cordaitalean forms were able to grow directly in the peat swamps (costanza, 1985). wetland and dryland floras with cordaitaleans were discussed by dimichele (2014) using as an example the pennsylvanian floras from north america. the study of dispersed cuticles from the central bohemian region is in its infancy, so it is not possible to produce a list of peat-forming cordaitaleans from this region. the clear evidence for the radnice member is that cordaites borassifolius (sternberg) unger (šimůnek et al., 2009) and possibly also c. wartmannii šimůnek and c. theodorii šimůnek & haldovský sp. nov. lived in coal swamps. dimichele & phillips (1994) demonstrated the greatest abundance of cordaitaleans in the duckmantian, bolsovian and early asturian peat swamps in america. in comparison with the bohemian massif, the greatest diversity of cordaitaleans occurs in the lower bolsovian radnice member (šimůnek, 2007), however, these cuticles were isolated from specimens from roof shales or clastic and tuffitic partings, and therefore mostly from species that predominantly lived in clastic-swamp wetlands, but not directly in the peat swamps (gastaldo et al., 1995). the relatively high diversity of cordaitaleans in the bohemian massif is also seen in the middle asturian nýřany member in central bohemia, (the zircon dating revealed an older age for these srtrata that was previously supposed; opluštil, pers. com.). the asturian records fit with the observations by dimichele & phillips (1994) based on peat substrate floras. a relatively rich and diversified cordaitalean assemblage is known from roof-shales (clastic deposits) from the upper asturian of bohemia (šimůnek, 2007). this provides further evidence that the peat substrate wetland flora might differ from the clastic substrate flora. 6. conclusion a new species cordaites theodorii šimůnek & haldovský sp. nov. from the bolsovian of the kladno-rakovník basin is erected. this species is remarkable in having dentate leaf margins, not known from other cordaitaleans; both of its cuticles are strongly papillate. great variability has been observed on additional cuticles of cordaites wartmannii šimůnek from the libušín and pchery localities. in contrast to the holotype, new samples of cordaites wartmannii have much wider stomatiferous bands on the abaxial cuticle (up to 450 mm) and thus they resemble the stephanian cordaites barthelii šimůnek. they also have smaller polar subsidiary cells than the holotype. cordaites polynervus šimůnek has been shown to be conspecific with cordaites kladnoensis šimůnek, based on the similarity of their abaxial cuticles. the species cordaites kladnoensis (abaxial cuticle) resembles cordaites principalis morphotype 5 of zodrow et al. (2000) from canada and cordaites radcicensis šimůnek from the asturian of the plzeň basin. the later was found in mudstone, thus the habitat of cordaites kladnoensis is considered to be non-peat-forming. cuticles of peat-forming cordaitaleans are often strongly papillate, and cordaites wartmannii and cordaites theodorii have such characteristics. acknowledgement this research was conducted by the support of the grant agency of the czech republic, grant no. p210/10/0232. the authors thank to dr. c. j. cleal (cardiff, uk) for checking the english in the text, two anonymous reviewers of geobios and an anonymous reviewer of geologia croatica and dr. w. a. dimichele (washington d.c., usa) for their comments that improved the manuscript. references barthel, m. (1962):. mikropaläobotanische untersuchungen im rotliegenden des döhlener beckens. teil i.– jahrbuch des staatlichen museums für mineralogie und geologie zu dresden. 1962, 157–175. barthel, m. (1964): coniferen und cordaiten-reste aus dem rotliegenden des döhlener beckens.– geologie, 13, 1, 60–89. bashforth a.r., cleal, c.j., gibling, m.r., falcon-lang, h.j. & miller, r.f. (2014): paleoecology of early pennsylvanian vegetation on a seasonally dry tropical landscape (tynemouth creek formation, new brunswick, canada).– review of palaeobotany and palynology, 200, 229–263. bek, j., opluštil, s., drábková, j. & pšenička, j. (2015): the sub-arborescent lycopsid omphalophloios feistmantelii (o. feistmantel) comb. nov. emend. from the middle pennsylvanian of the czech republic.– bulletin of geosciences, 90/2. cleal, c.j. & shute, c.h. (2012): the systematic and palaeoecological value of foliage anatomy in late palaeozoic medullosalean seedplants.– journal of systematic palaeontology, 10/4, 1–36. doi: 10.1080/14772019.2011.634442. cleal, c.j. & thomas, b.a. (1995): palaeozoic palaeobotany of great britain.– chapman & hall. london, 295 p. costanza, s.h. (1985): pennsylvanioxylon of middle and upper pennsylvanian coals from the illinois basin and its comparison with mesoxylon.– palaeontographica, abt. b, 197, 81–121. dijkstra, s.j. & van amerom, h.w.j. (1998): fossilium catalogus ii: plantae. pars 99 – backhuys publishers, leiden, 1–195. dimichele, w.a. (2014): wetland-dryland vegetational dynamics in the pennsylvanian ice age tropics.– international journal of plant sciences, 175/2, special issue, 123–164. dimichele, w.a. & phillips, t.l. (1994): paleobotanical and paleoecological constraints on models of peat formation in the late carboniferous of euramerica.– palaeogeography, palaeoclimatology, palaeoecology, 106, 39–90. dimichele, w.a., cecil, c.b., montañez, i.p. & falconlang, h.j. (2010): cyclic changes in pennsylvanian paleoclimate and effects on floristic dynamics in tropical pangaea.– international journal of coal geology, 83/2–3, 329–344. falcon-lang, h.j. (2003a): late carboniferous tropical dryland vegetation in an alluvial plain setting, joggins, nova scotia, canada.– palaios, 18/3, 197–211. falcon-lang, h.j. (2003b): anatomically preserved cordaitalean trees from a dryland alluvial plain setting, joggins, nova scotia.– atl. geol., 39/3, 259–265. falcon-lang, h.j. & bashforth, a.r. (2004): pennsylvanian uplands were forested by giant cordaitalean trees.– geology, 32/5, 417–420. geologia croatica 68/2geologia croatica 102 falcon-lang, h.j., benton, m.j., braddy, s.j. & davies, s.j. (2006): the pennsylvanian tropical biome reconstructed from the joggins formation of nova scotia, canada.– journal of the geological society of london, 163, 561–576. falcon-lang, h.j., jud, n.a., nelson, w.j., dimichele, w.a., chaney, d.s. & lucas, s.g. (2011): pennsylvanian coniferopsid forests in sabkha facies reveal the nature of seasonal tropical biomes.– geology, 39/4, 371–374. feistmantel, o. (1876): die versteinerungen der bőhmischen kohlenablagerungen. iii. abteilung.– palaeontographica, 23, 223–316. florin, r. (1931): untersuchungen zur stammesgeschichte der coniferales und cordaitales.– kunglige svenska vetenskapsakedemiens handlingar, tredje serien, 10/1, 1–588. gastaldo, r.a., pfefferkorn, h.w. & dimichele, w.a. (1995): taphonomic and sedimentologic characterization of roofshale floras.– in. lyons, p.c. & morey, e.d., wagner r.h. (eds.): historical perspective of early twentieth century carboniferous papeobotany in north america (w.c. darrah volume), boulder, colorado.– geological society of america memoir, 185, 341–352. jongmans, w.j. & dijkstra, s.j. (1968): fossilium catalogus, ii: plantae – pars 70. cordaitales 1, 1–112. kerp, h. (1990): the study of fossil gymnosperms by means of cuticular analysis.– palaios, 5, 548–549. kerp, h. & krings, m. (1999): light microscopy of fossil cuticles.– in: jones, t.p. & rowe, n.p. (eds.): fossil plants and spores. modern techniques. geological society, london, 52–56. krings, m. (2000): the use of biological stains in the analysis of the late palaeozoic pteridosperm cuticles.– review of palaebotany and palynology, 108, 143–150. krings, m. & kerp, h. (1997): an improved method for obtaining large pteridosperm cuticles.– review of palaebotany and palynology, 96, 453–456. liu, z.-h., geng, b.-y., wang, s.-j. & li, c.-s. (1998): on cordaites neimengensis sp. nov from lower permian of zhungeerqi, inner mongolia, china.– acta botanica sinica, 40, 4, 383–388. meyen, s.v. (1984): basic features of gymnosperm systematics and phylogeny as evidenced by the fossil record.– the botanical review, 50, 1, 1–112. němejc, f. (1932): stratigraphické výzkumy, konané s hlediska paleobotanického v uhelných revírech jižní části plzeňské kamenouhelné pánve v letech 1928–1932.– hornický věstník, 14/33, 241–245, 268–273, 295–300, 320–333, 345–350. němejc, f. (1936): studies on the alethopterids of the permocarboniferous of central bohemia (with remarks on forms collected in other bohemian coal districts).– vestník královské české společnosti nauk, tř. ii, 1–18. němejc, f. (1940): the pecopterides of the coal districts of bohemia.– sborník národního muzea (praha), ř. b, 1, 1–28. němejc, f. (1947): the lepidodendraceae of the coaldistricts of central bohemia (a preliminary study).– sborník národního muzea (praha), ř. b, 3 (2), 1–28. opluštil, s. (2005a): evolution of the middlewestphalian river valley drainage system in central bohemia (czech republic) and its palaeogeographic implication.– palaeogeography, palaeoclimatology, palaeoecology, 222, 223–258. opluštil, s. (2005b): the effect of paleontography, tectonics and sediment suply on quality of coal seams in continental basins of central and western bohemia (westphalian), czech republic.– international journal of coal geology, 64, 173– 203. doi:10.1016/j.coal.2005.03.022 opluštil, s., pšenička, j., libertín, m. & šimůnek, z. (2007): vegetation paterns of westphalian and lower stephanian mire assemblages preserved in tuff beds of the continental basins of czech republic.– review of palaeobotany and palynology, 143, 107–154. doi 10.1016/j.revpalbo.2006.06.004 opluštil, s., pšenička, j., bek, j. wang, j., feng, z., libertin, m., šimůnek, z., bureš, j. & drábková j. (2014): t0 peat-forming plant assemblage preserved in growth position by volcanic ash-fall: a case study from the middle pennsylvanian of the czech republic.– bulletin of geosciences, 89/4, 773–818. doi 10.3140/bull.geosci.1499 pešek, j. (1994):. carboniferous of central and western bohemia (czech republic).– czech geological survey, prague. 61 p. poole, i. & kürschner, w.m. (1999): stomatal density and index: the practice.– in: jones, t.p. & rowe, n.p. (eds.) fossil plants and spores. modern techniques. geological society, london. 257–260. raymond, a., lambert, l., costanza, s., slone, e.j. & cutlip, p.c. (2010): cordaiteans in paleotropical wetlands: an ecological re-evaluation.– international journal of coal geology, 83/2–3, 248–265. rothwell, g.w. (1988): cordaitales– in: beck, c.b. (ed.): origin and evolution of gymnosperms. columbia university press, new york, 273–297. salisbury, e.j. (1927): on the causes and ecological significance of stomatal frequency with special reference to the woodland flora.– philosophical transactions of the royal society (london) b, 216, 1–65. šimůnek, z. (2007): new classification of the genus cordaites from the carboniferous and permian of the bohemian massif, based on cuticle micromorphology.– acta musei nationalis. pragae, series b., historia naturalis, 62/3–4, 97–210. šimůnek, z. (2008): the asturian and cantabrian floral assemblages with cordaites from the plzeň basin (czech republic).– studia geologica polonica, 129, 51–80. šimůnek, z. (2014): first cuticles of cordaites unger from the stephanian b of the krkonoše piedmont basin (czech republic).– palaeontographica abt. b, 290/4–6, 127–139. šimůnek, z. & florjan, s. (2013): the pennsylvanian cordaitalean dispersed cuticles from the upper silesian basin (poland).– review of palaeobotany and palynology, 197, 26–49. šimůnek, z., opluštil, s. & drábková, j. (2009): cordaites borassifolius (sternberg) unger (cordaitales) from the radnice basin (bolsovian, czech republic).– bulletin of geosciences, 84/2, 301–336. unger, f. (1850): genera et species plantarum fossilium.– wilhelmum braumüller, vienna, 627 p. wagner, r.h. (1984): megafloral zones of the carboniferous.– compte rendu 9e congrès international de stratigraphie et de géologie du carbonifère (washington, 1979), 2, 109–134. wartmann, r. (1969): studie über die papillen-förmigen verdickungen auf der kutikule bei cordaites an material aus dem westphal c des saar-karbons.– argumenta palaeobotanica, 3, 199–207. weithofer, k.a. (1902): geologische skizze des kladno-rakonitzer kohlenbeckens.– verhandlungen k. k. geologischen reichsanstalt, 399–420. zajíc, j. (2012): otázka stáří nejvyšší části líňského souvrství (mšenskoroudnická pánev, český masiv) – nové indicie z vrtu be-1 bechlín [contribution to the question of age of the uppermost part of the líně formation (mšeno-roudnice basin, bohemian massif)].– zprávy o geologických výzkumech v roce 2011, 59–62. zodrow, e.l., šimůnek, z. & bashforth, a.r. (2000): new cuticular morphotypes of „cordaites principalis (germar) geinitz“ from the canadian carboniferous maritimes basin.– canadian journal of botany, 78/2, 135–148. manuscript received january 19, 2015 revised manuscript accepted may 29, 2015 available online june 19, 2015 šimůnek and haldovský: contribution to the knowledge of cordaites species from the kladno-rakovník basin, middle pennsylvanian, czech republic geologia croatica 103 plate 1 a–d cordaites wartmannii šimůnek, libušín, schoeller mine, kladno-rakovník basin, radnice member, bolsovian (coll. cgs, zš 246). a – a leaf with venation (holotype), material of slides 113/1–2. scale bar = 1 cm; b – detail of the venation from fig. a, veins visible as doubled and alternating with sclerenchymatous strands. scale bar = 1 mm; c – a wide leaf fragment from which slides 395/1–8 have been prepared (coll. cgs, zš 303). scale bar = 1 cm; d – detail of the venation from fig c. it has the same pattern as fig. b; e–g fragments of leaves of cordaites wartmannii šimůnek, and cordaites theodorii šimůnek et haldovský sp. nov. (holotype), pchery, theodor mine, kladno-rakovník basin, radnice member, bolsovian (coll. cgs, zš 350). scale bar = 1 cm; f and h – details of venation; f – from the large left leaf; g – from the small right leaf from the fig. e. both venations exhibit “doubled” veins and probably belong to cordaites wartmannii. scale bar = 1 mm; h–j cordaites kladnoensis šimůnek, pchery, theodor mine, kladno-rakovník basin, radnice member, bolsovian; h – leaf fragment, scale bar = 1 cm; i – detail of venation from the leaf impression with fine veins. scale bar = 1 mm; j – detail of venation from the opposite side of phytoleim (coll. cgs, zš 358a). scale bar = 1 mm. geologia croatica 68/2geologia croatica 104 plate 2 cuticles from cordaites wartmannii šimůnek (holotype, slide 113/1), libušín, schoeller mine. a–c adaxial cuticle. a – adaxial cuticle with dark somatal rows. scale bar = 100 mm; b – details of dark stomatiferous bands. scale bar = 50 mm; c – detail of two stomatal complexes. scale bar = 25 mm; d–f abaxial cuticle; d – cuticle with three stomatiferous bands. scale bar = 100 mm; e–f detail with a stomatiferous band and stomata and small papillae on epidermal cells; e – scale bar = 50 mm; f – scale bar = 25 mm; g – detail of two stomatal complexes and epidermal cells. scale bar = 25 mm. šimůnek and haldovský: contribution to the knowledge of cordaites species from the kladno-rakovník basin, middle pennsylvanian, czech republic geologia croatica 105 plate 3 cuticles from cordaites wartmannii šimůnek, libušín, schoeller mine, slide no. 395/5; a adaxial cuticle with dark somatal rows. scale bar = 50 mm; b detail of dark stomatal row with a stomatal complex. scale bar = 25 mm; c–d outer view of adaxial cuticle with openings above guard cells, sem stub no. 25; c – scale bar = 50 mm; d – scale bar = 10 mm; e–g abaxial cuticle with stomatiferous and non-stomatiferous bands; e – note relatively wide stomatiferous bands and some strongly cutinised cells in non-stomatiferous bands. scale bar = 100 mm; f – abaxial cuticle with relatively narrow stomatal bands and small papillae on epidermal cells. scale bar = 50 mm; g – detail of some stomatal complexes within stomatiferous band. note small polar subsidiary cells. scale bar = 25 mm. geologia croatica 68/2geologia croatica 106 plate 4 cuticles from cordaites wartmannii šimůnek a–f libušín, schoeller mine locality; a – detail of stomatal complexes from pl. 3f. scale bar = 10 mm; b–f abaxial cuticle in sem, stub 25, outer view; b – low magnification with stomatal bands and stomatal openings. scale bar = 100 mm; c – stomatiferous band with guard cells visible. scale bar = 50 mm; d and e – inner view of stomatal complexes with very visible guard cells. scale bar = 10 mm; f – outer view on the abaxial cuticle. scale bar = 100 mm; g–l adaxial cuticle, pchery, theodor mine locaitty g–h alternating non-stomatiferous and dark stomatiferous bands. slide 518/8. scale bars = 100 (g) and 50 (h) mm; i – detail of cells of non-stomatiferous band with burst papillae-like objects, slide 518/13. scale bar = 25 mm; j–k adaxial cuticle with dark stomatiferous bands, slide 518/13; j – scale bar = 100 mm; k – scale bar = 50 mm; l – detail of the dark stomatiferous band from pl. 4k with stomata. note proximal papillae on lateral subsidiary cells. scale bar = 25 mm. šimůnek and haldovský: contribution to the knowledge of cordaites species from the kladno-rakovník basin, middle pennsylvanian, czech republic geologia croatica 107 plate 5 cuticles from cordaites wartmannii šimůnek pchery, theodor mine locality a–d sem images from inner side of the adaxial cuticle, sem stub 56; a – general view of abaxial cuticle. scale bar = 100 mm; b – view to stomatal complex. scale bar = 20 mm; c – another view of adaxial cuticle. scale bar = 100 mm; d – adaxial cuticle with stomata – detail from pl. 5c. scale bar = 25 mm; e–g abaxial cuticles, slide 518/6; e – abaxial cuticle with stomatiferous and non-stomatiferous bands. scale bar = 100 mm; f – detail of the stomatiferous band with stomatal complexes from pl. 5e. scale bar = 50 mm; g – detail of stomatal complexes from fig. f. scale bar = 25 mm; h–k sem images of abaxial cuticle. sem stub 56; h – outer view of abaxial cuticle with stomatal openings above guard cells and papillae on the surface. scale bar = 25 mm; i – inner view of the abaxial cuticle with prominent anticlinal walls, guard cells are not very discernible. scale bar = 50 mm; j – abaxial cuticle with indiscernible guard cells, but with very prominent anticlinal walls of polar subsidiary cells. scale bar = 20 mm; k – inner view of the abaxial cuticle. cells of stomatiferous and non-stomatiferous bands are clearly distinguishable. scale bar = 50 mm. geologia croatica 68/2geologia croatica 108 plate 6 cordaites theodorii šimůnek & haldovský sp. nov., pchery, theodor mine locality. a leaf margin with teeth. slide 518/1. scale bar = 250 mm; b detail of a tooth from pl. 6a. scale bar = 25 mm; c surface of the adaxial cuticle with elongated cells and many papillae. slide 518/8, scale bar = 100 mm; d detail of adaxial cuticle from pl. 6c. scale bar = 50 mm; e detail of strongly papillate cells of the adaxial cuticle from pl. 6d. scale bar = 25 mm; f papillate cells of adaxial cuticle, slide 518/13. scale bar = 25 mm. šimůnek and haldovský: contribution to the knowledge of cordaites species from the kladno-rakovník basin, middle pennsylvanian, czech republic geologia croatica 109 plate 7 a–f cordaites theodorii šimůnek & haldovský sp. nov., pchery, theodor mine locality; a – strongly papillate abaxial cuticle. slide 518/1. scale bar = 50 mm; b – detail of abaxial cuticle from pl. 7a with stomata. scale bar = 25 mm; c–d strongly papillate cells of abaxial cuticles. note proximal papillae on subsidiary cells pointing to the center of the stoma. slide 518/2. scale bar = 25 mm; e – stomata arranged in rows, slide 518/2. scale bar = 25 mm; f – detail of two stomata. note many papillae. slide 518/2. scale bar = 25 mm; g–h cordaites wartmanni šimůnek. pchery, theodor mine locality. poorly preserved cuticles with prominent polar subsidiary cells. the other cells, including the guard cells are poorly discernible. g – scale bar = 50 mm; h – scale bar = 25 mm. geologia croatica 68/2geologia croatica 110 plate 8 a–d cordaites kladnoensis šimůnek (holotype of cordaites polynervus šimůnek, slide 182/1) tuchlovice, nosek mine locality; a–d adaxial cuticles; a – daxial cuticle with more or less regular dark stomatal rows. scale bar = 250 mm; b – detail from fig. a. scale bar = 100 mm; c – detail of a dark stomatiferous band with stomatal complexes from pl. 8b. scale bar = 50 mm; d – detail of three stomatal complexes from pl. 8c. scale bar = 25 mm; e–h abaxial cuticle; e – a stomatal complex with strongly cutinised crypt above guard cells, detail from fig. h. scale bar = 25 mm; f – view of an abaxial cuticle with three stomatifereous bands. scale bar = 100 mm; g – detail of a stomatiferous band from fig. f. with strongly cutinised crypts above guard cells and anticlinal walls in the corners of cells. scale bar = 50 mm; h – close up of a stomatiferous band from pl. 8g to see in more detail strongly cutinised crypts and anticlinal walls. scale bar = 25 mm; i venation pattern of cordaites kladnoensis šimůnek (holotype of cordaites polynervus šimůnek) inv. no. zš 247, scale bar = 1 mm; j–l adaxial cuticle of cordaites kladnoensis šimůnek, pchery, theodor mine locality, j – dark stomatiferous band with stomata. slide 543/1. scale bar = 50 mm; k – close up of stomatal complexes from fig. j. scale bar = 25 mm; l – adaxial cuticle with a dark stomatiferous band. slide 543/3 scale bar = 50 mm. šimůnek and haldovský: contribution to the knowledge of cordaites species from the kladno-rakovník basin, middle pennsylvanian, czech republic geologia croatica 111 plate 9 adaxial cuticle of cordaites kladnoensis šimůnek, pchery, theodor mine locality. slide 543/4; a adaxial cuticle with two dark stomatiferous bands. scale bar = 50 mm; b close up of dark stomatiferous band from pl. 9a. scale bar = 25 mm; c close up of two stomata from the stomatiferous band on pl. 9b. scale bar = 25 mm. 2016 | 69/3 | 307–316 | 10 figs. | 1 tab. | www.geologia-croatica journal of the croatian geological survey and the croatian geological society a cave response to environmental changes in the late pleistocene: a study of budimirica cave sediments, macedonia marjan temovski1*, petr pruner2,3, helena hercman4 and pavel bosák2,3 1 institute for nuclear research of the hungarian academy of sciences, hertelendi laboratory of environmental studies, bem tér 18/c, h-4026 debrecen, hungary; (temovski.marjan@atomki.mta.hu) 2 czech academy of sciences, institute of geology v. v. i., rozvojová 269, 165 00 praha 6, czech republic; (pruner@gli.cas.cz; bosak@gli.cas.cz) 3 slovenian academy of sciences and arts, scientific research centre, institute of karst research, titov trg 2, 6230 postojna, slovenia 4 polish academy of sciences, institute of geological sciences, twarda 51/55, 00-818 warszawa, poland; (hhercman@twarda.pan.pl) doi: 10.4154/gc.2016.29 abstract budimirica cave is a small cave located in the southern part of the republic of macedonia, in the kamenica valley, a tributary to the crna reka and part of the vardar river drainage network. the response of the cave to late pleistocene environmental changes is interpreted based on a detailed study of cave sediments, with previous data being supplemented, reinterpreted and compared to the ohrid lake palaeoclimate record. the oldest exposed speleothems in the budimirica sediment profile were deposited during the mis 5a (radiometric age of ca 83 ka). sands to clays in the overburden are characterized by cycles separated by short-lived interruptions in deposition. they were deposited from a number of repeated flood events likely during the mis 4 stage, the weichselian (wurmian) glaciation, correlating to aggradation in the kamenica valley. the top flowstone is correlated with a warmer climate excursion at 45–50 ka (mis 3) recor­ ded from the ohrid lake deposits. the whole section was extensively eroded during the mis 2 stage, due to strong incision in the kamenica valley, indicated by knickpoint retreat. the erosion surface is overlain by a fossil-bearing breccia (with ursus spelaeus) derived from frost shattering of the cave walls close to the entrance due to climate deterioration and enlargement of the entrance by slope retreat during the mis 2 stage. budimirica cave sediments reflect changes in the kamenica valley, as well as the environmental changes during the last glacial­interglacial cycle, with clastic cave sediments deposited during glacial stadials, and erosion and flowstone deposition characteristic of the interstadials. they also allow reconstruction of the evolution of the kamenica valley during the late pleistocene, with a general trend of valley incision hindered by climate influenced river aggradation, but reinforced by river knickpoint retreat. 1. introduction caves serve as especially good archives of past environmental information due to both the sensitivity of karst systems to a wide range of environmental changes (i.e. change of recharge dyna­ mics, increase/decrease and character of sediment supply, change of dissolved co2 content etc.), and great capability to protect the record from erosion as compared with the surface (e. g., häusel­ mann et al., 2008, 2015). most of the recent studies have con­ centrated on analysis of palaeoenvironmental records from spe­ leothems (e. g., lascu & feinberg, 2011; or summary in fairchild & baker, 2012). there exist only rare examples, when speleothems record longer time­span than relatively short climatic optima (like in pleistocene), but such profiles are mostly pre­pleistocene in age (bosák et al., 2002; häuselmann et al., 2015). clastic cave fill preserves the palaeoenvironmental re­ cord and evidence of its changes in similar detail (see summaries a. o. in sasowsky & mylroie, 2004; ford & williams, 2007, or zupan hajna et al., 2008) but usually over much longer time­spans than speleothems. the disadvantage of such a record results from complications by the number of post­deposi­ tional changes (bull, 1981) and hiatuses of variable lengths, sediment reworking and redepositon (bosák et. al., 2000; zu­ pan hajna et al., 2008, 2010). moreover, most caves preserve results of only the last depositional cycle, as deposits of previous cycles were usually exhumed due to the general function of cave systems. this can lead to the absence of cave sediments from certain time­periods in whole regions, e.g. middle pleistocene sediments are missing in caves of the bohemian karst (central czech republic; horáček & ložek, 1988). we present an example of palaeoenvironmental analysis of clastic cave sediments belonging to the last depositional cycle of a small cave in the southern parts of the republic of macedonia. the interpretation is based on detailed research on the stratigra­ phy, composition and age of cave sediments. previous data (te­ movski, 2016) is supplemented, reinterpreted and compared to the palaeoclimate record from the ohrid lake sediments. the results provide insight into the effect of late pleistocene environ­ mental changes on landscape evolution in the area. 2. cave and sediments the budimirica cave (400 m a. s. l.) is located in the right slope of the lower part of the kamenica valley (figs. 1 and 2). the ka­ menica river is a tributary to the crna reka, the second longest tributary of the vardar river, the main drainage system of the republic of macedonia, draining towards the aegean sea. the area is a part of the vitačevo plateau (800–1.000 m a.s.l.), com­ posed mostly of pliocene and early pleistocene pyroclastic sedi­ ments. they were deposited in lacustrine to fluvial environments of the tikveš basin, as part of the pliocene­pleistocene central macedonian lake. in places they cover palaeogene conglome­ rates (tertiary tikveš basin), and rocks of the vardar zone pre­ cenozoic basement: cretaceous limestones and flysch (figs. 1 article history: manuscript received january 25, 2016 revised manuscript accepted july 30, 2016 available online october 07, 2016 keywords: cave sediments, palaeoenvironmental changes, late pleistocene, budimirica cave, macedonia g eo lo gi a c ro at ic a geologia croatica 69/3308 figure 1. location of the studi­ ed site within the regional geo­ logical structure of the republic of macedonia. major geo tec­ tonic units are after arsovski (1997). figure 2. a geological map of the western part of the vitačevo plateau showing the location of budimirica cave (compiled from dumurdžanov et al., 1976; hristov et al., 1965; rakićević et al., 1965; and rakićević & pendžerkov ski, 1970). g eologia c roatica temovski et al.: a cave response to environmental changes in the late pleistocene: a study of budimirica cave sediments, macedonia 309 and 2; dumurdžanov et al., 1976, 2004). the central mace­ donian lake was drained probably no later than during the mid­ dle pleistocene (dumurdžanov et al., 2005) as a result of uplift in the central parts of the balkan peninsula and subsidence in the area of aegean sea (dumurdžanov et al., 2004). the kamenica river cut its valley through the pyroclastic deposits down to the pre­cenozoic basement, uncovering upper creta­ ceous (turonian) limestones and exposing them to weathering and karstification (temovski, 2016). the budimirica cave is 105 m long and consists of two branching passages with northeastern general direction (mana­ kovik, 1971). the cave passages formed along the strike direc­ tion of turonian limestones and contain speleogens indicating spe­ leogenesis in phreatic to epiphreatic conditions (temovski, 2016). a paragenetic morphology (ceiling channels, pendants) is developed especially above still preserved cave sediments (fig. 4). a large excavated pit in yellow­ to orange­coloured cave sediments (5 m long, 1.5 m wide, and 1–1.5 m deep) is situated in figure 3. view of the studied sediments in budimirica cave: a – the whole profile below the collapsed flowstone block with major unconformities indicated; b – close­view of the upper part with positions of palaeomagnetic sampling boxes and examples of neptunian dykes (n) along the plane at 25.5 cm; c – relation­ ship of yellow sediments to the brown breccia deposit, with the black ellipse showing the location of collected fossil samples and close­view photo showing frag­ ments of an ursus spelaeus molar. photos by m. temovski. figure 4. detail of the left passage with cave morphology, sediment relationships and location of the sampling profile. modified from temovski (2016). g eo lo gi a c ro at ic a geologia croatica 69/3310 the middle part of the left passage (figs. 3 and 4). in the ne part of the pit, the sediment profile starts with flowstone at the bottom, which is followed by ca 1.5 m thick deposits of silt, clay and sand, covered by a 30 cm thick collapsed flowstone block (figs. 4 and 5). above (and beside) this flowstone block, in one part, the clas­ tic sequence continues with yellowish gravel, sand and silt up to 1 m thick, covered by flowstone (figs. 5). this whole section is eroded and covered with brown fossil­bearing breccia in the sw part of the pit (figs. 3c and 5). the breccia deposits are covered with a 10–15 cm thick organic deposit close to the cave entrance. the clastic sequence below the collapsed flowstone block (0 cm), down to the bottom flowstone (155 cm) was studied in detail (temovski, 2016). the sequence contains some principle un­ conformities expressed by dark films (mn and/or fe compounds) and desiccation cracks filled by overlying sediments, together with smaller neptunian dykes (fig.3b). palaeomagnetic param­ eters of 56 samples collected from the middle part (between 25.5 and 155 cm) showed normal polarized magnetization with a mean palaeomagnetic declination of 2.6° (temovski, 2016). 3. methods and results 3.1. palaeomagnetic analysis samples were analyzed at the institute of geology of the czech academy of sciences. in total 20 oriented samples from previ­ ously non analyzed upper (clastic) and lower (flowstone) parts of the profile (figs. 4 and 6) were collected for palaeomagnetic dat­ ing using the high­resolution sampling methodology described by zupan hajna et al. (2008). palaeomagnetic data for the middle part of the profile was previously published, with 56 mea­ sured samples (temovski, 2016). unconsolidated sediments (13 samples) from the upper part of the profile (0-25.5 cm) were collected in small plastic cubes from individual horizons. two solid hand samples from the speleothem in the lower part of the profile (168-181 cm) were cut into 7 cubes 20 x 20 x 20 mm. in the laboratory, they were measured on the jr­6a spinner mag­ netometer (jelínek, 1966) and/or 2g superconducting rock magnetometer with incorporated af unit. 17 specimens were demagnetized by the alternating field (af) procedures, up to the field of 100 mt in 10 to 13 steps and 3 specimens were demag­ netized thermally (td) using the mavacs apparatus (příhoda et al., 1989). the af demagnetization by lda–3a or srm de­ magnetizer including td demagnetization gave considerably good results. the remanent magnetization (rm) of specimens in their natural state (nrm) is identified by the symbol m. graphs of normalized values of m/mo= f(h) were constructed for each analyzed specimen. volume magnetic susceptibility (ms) was measured on a kly­4 kappa­bridge (jelínek, 1973). separa­ tion of the respective remanent magnetization components was carried out by multi­component kirschvink analysis (kirsch­ vink, 1980). the statistics of fisher (1953) were employed for calculation of mean directions of the pertinent remanence com­ ponents derived by the multi­component analysis. both previ­ ously published (56 samples) and new data (20 samples) were used for the statistical analyses, with data from four samples ex­ cluded where the maximum angular deviation (mad) was higher than 10 for the multi­component analysis, leaving a total of 72 analyzed samples. examples of the td and af demagnetization of samples (position 168 and 181 cm) with normal (n) palaeomagnetic po­ larity are presented in fig. 6. directions of c­components of re­ manence with normal palaeomagnetic polarity for the whole pro­ file are given on fig. 7. recalculated mean palaeomagnetic directions of n polarized c-components for the whole profile are d = 359.0° and i = 46.5°. the sediments from the profile showed only normal polarized magnetization. mean values of palaeomagnetic directions of the whole profile are documented in table 1. the values of palaeomagnetic directions in different segments document palaeo­ secular variation. the distribution of the nrm and ms in the pa laeomagnetic profile (fig. 8) can indicate changes in deposi­ tion as well as the change of external climatic conditions. figure 5. relationship of sampled sediments to other cave fills and the position of major unconformities (dotted line) in the pit of the left passage. upper illustra­ tion (a) shows a frontal view of the lower part of the sampled profile with locations of the flowstone samples. modified from temovski (2016). temovski et al.: a cave response to environmental changes in the late pleistocene: a study of budimirica cave sediments, macedonia 311 g eologia c roatica 3.2. radiometric dating (u-series) the th/u (u­series) dating was performed in the geochrono­ logy laboratory, institute of geological sciences, polish acade my of sciences in warsaw (analysts helena hercman). standard chemical procedures for uranium and thorium separation from carbonate samples were used (ivanovich & harmon, 1992). the activity was measured by α-spectrometry, using an ortec octete pc. spectral analyses and age calculations were made with uranothor 2.5 software, which is the standard software in the geochronology laboratory in warsaw (gorka & hercman, 2002). the quoted errors are one standard deviation. the bottom flowstone deposit (sample bud_00) was dated to 83 (+16/­14) ka (fig. 5, tab. 2). dating of sample bud_02 (which belongs to a stratigraphically older layer) was not successful due to strong detrital th contami­ nation. 3.3. geomorphological analyses of the kamenica valley a longitudinal profile of the kamenica river was constructed from 1:25000 topographic maps (vojnogeografski insti­ tut, 1973) using the global mapper v.16 and grapher v.11, and was analyzed to identify changes in channel slope, with geologi­ cal information along the profile obtained from 1:25000 geological maps (geološki zavod – skopje, unpublished). field observations in the kamenica valley near budimirica cave registered the remnant of a river terrace opposite the cave at 80 m relative elevation. combined field and topographic map observations registered three river terraces in the middle part of the kamenica valley, nearby temna peštera – dragožel, with relative elevations of 30 m, 60 m, and 80 m above the kamenica river. their position shows their relationship to caves in both lo­ calities (temovski, 2016). figure 6. example (a) of the af demagnetization (position 181 cm) and (b) the td demagnetization (position 168 cm) of samples with normal palaeomagnetic po­ larity from the budimirica cave. upper left – a stereographic projection of the natural remanent magnetization of a sample in the natural state (cross section) and after progressive af and/or td demagnetization; upper right – the zijderveld diagram: solid circles represent projection on the horizontal plane (xy), open circles represent projections on the north–south vertical plane (xz); lower left – a graph of normalized values of the remanent magnetic moments versus demagnetizing fields: m – modulus of the remanent magnetic moment of a sample subjected to af and/or td demagnetization. lower right – a graph of the normalized values of volume magnetic susceptibility versus thermal demagnetizing fields: k – value of volume magnetic susceptibility of a sample subjected to td demagnetization. figure 7. directions of c­components of remanence with normal palaeomag­ netic polarity for the whole profile in budimirica cave. stereographic projection, full (open) small circles represent projection onto the lower (upper) hemisphere. the mean directions calculated according to fisher (1953) are marked by a small cross across a circle, the confidence circle at the 95% probability le vel is circumscribed about the mean direction. table 1. mean palaeomagnetic directions for the whole profile in budimirica cave, recalculated using data from this study and temovski (2016). budimirica cave polarity mean palaeomagnetic directions α95 [o] k n d [o] i [o] n 359.0 46.51 2.42 51.12 72 explanations: d, i – declination and inclination of the nrm; α95 – semi­vertical angle of the cone of confidence calculated according to fischer (1953) at the 95% probability level; k – precision parameter; n – number of analysed samples. table 2. u­series dating results. sample lab. no. 238u [ppm] 234u/238u 230th/234u 230th/232th age [ka] bud_00 w 3152 0.0331±0.003 1.09±0.13 0.54±0.07 43 +16 83 –14 g eo lo gi a c ro at ic a geologia croatica 69/3312 figure 8. basic magnetic properties for the whole profile in the budimirica cave. data in red is from this study, others after temovski (2016). note that flowstone samples bu01 (a­d) are younger than samples bu2 (a­c), and are found at lower position as a results of the slope of the flowstone deposit (see fig. 5 for clear view of relationship). g eologia c roatica temovski et al.: a cave response to environmental changes in the late pleistocene: a study of budimirica cave sediments, macedonia 313 3.4. ohrid lake palaeoenvironmental record detailed studies of sediments from ohrid lake (fig. 1), from seve­ ral cores at different locations, have been undertaken recently, with published data providing palaeoenvironmental information dating back to the middle pleistocene (lacey et al., 2016 and references therein). to compare with the environmental changes registered within the budimirica cave sediments we used late pleistocene palaeoclimate data derived from a study of a multi­proxy record from the sediments of jo2004­1 core, from the southwestern part of ohrid lake (belmecheri et al., 2010; lezine et al., 2010). 4. discussion 4.1. cave response to late pleistocene environmental changes passages of the budimirica cave formed along the strike direc­of the budimirica cave formed along the strike direc­the strike direc­ tion of the turonian limestones in phreatic to epiphreatic environ­of the turonian limestones in phreatic to epiphreatic environ­ ments (fig. 9a). the age of speleogenesis cannot be precisely stated, but it is possible that it was connected with the period be­ fore the incision of the kamenica river valley, indicated by small cave remnant on the opposite side of the valley (the karši budi­ mirica cave; temovski, 2016). paragenetic speleogens (ceiling channels, pendants) are developed in many places, especially above the preserved cave sediments, indicating the upward de­ velopment of passages after sediment aggradation in the vadose evolution stages of the cave (temovski, 2016). the flowstones on the passage floor were deposited in va­ dose conditions (fig. 9b). a radiometric age of ca 83 ka suggests an origin during the interstadial of the marine isotopic stage (mis) 5a. this period was characterized by a warm and wet cli­ mate, supporting an increase in vegetation cover and carbon di­ oxide production according to the ohrid lake record (bel­ mecheri et al., 2010; lezine et al., 2010), although having less favourable conditions compared to the last (eemian) inter­ glacial (mis 5e). the dated flowstone layer (sample bud_00) represents the upper layer below the clastic deposits, and it is covering an older layer of flowstone separated with a thin clay layer. although the dating of the older layer was unsuccessful, the stratigraphy (fig. 5) indicates that the lower layer (bud_02) was likely deposited in older interstadials during mis 5, with clay deposits deposited during the stadial period. the basal flowstone is covered with clastic deposits (up to the collapsed flowstone block) composed of two different lithos­ tratigraphic segments divided by a distinct unconformity at 123 cm: a sandy one in the lower part and a generally fine-grained one above (temovski, 2016). the sandy character of the lower segment indicates the higher energy of the flowing water than in later overlying cycles. upper segment sediments are composed of well-sorted fine-grained sediments, and are a typical example of internal cave facies lithology (sensu kukla & ložek, 1958). sediments were sorted when transported through the shal­ low phreatic/epiphreatic siphonal cave system, where the coarser­grained components were deposited closer to ponor(s). the cave fill represents the results of repeating floods in a rela­ tively calm but not completely stagnant sedimentary environ­ ment (slackwater deposits sensu bosch &white, 2004), i. e. originating from waning floodwaters or other pulsed flow (cf. ford & williams, 2007). such a sedimentary environment has been known from number of caves in the north dinaric classical karst and adjacent areas (e.g., zupan hajna et al., 2008, 2010). the profile consists only of a few single flood events (cycles) limited by unconformities with short­lasting hiatuses (compac­ tion and dewatering, desiccation, small erosions). each flood partly eroded older sediments and deposited its load. the depo­ sitional and post­depositional textures (e.g. water­escape struc­ tures) indicate the very rapid depositional rates, which is sup­ ported by uncentered secular variation detected from the calculation of mean values of palaeomagnetic directions in the upper profile segment. the cyclic character resulted from a fluc­ tuating hydrological regime in the cave and reflected environ­ mental changes influencing the recharge regime and base level position in the kamenica valley. individual layers, which also differ in their magnetic properties (ms and nrm values), reacted to changes in the catchment area (change of source rocks, con­ tinuing erosion of weathering profiles) and external climatic changes (cf. e. g., sroubek et al., 2001). figure 9. schematic illustration of the evolution of budimirica cave deposits and their relationship to the changes in the kamenica valley with their interpreted ages. see text for explanation. red line represents changes in elevation of kamenica river talweg. g eo lo gi a c ro at ic a geologia croatica 69/3314 the studied sediments contain minerals that are also typical for the volcanic and volcaniclastic source rocks and their weathe­ ring products – especially sanidine, smectite (motmorillonite) and kaolinite (temovski, 2016). according to the kaolinite content and absence of macroscopically visible sedimentary particles de­ rived from volcanic and volcaniclastic rocks, the source material was composed of re­deposited materials derived from well­de­ veloped weathering profile(s). only normal polarized magnetization is typical for the stud­ ied sediments. mean values of palaeomagnetic directions calcu­ lated from the whole profile are close to the present magnetic field – the value of mean palaeomagnetic declination of 359° is close to the present magnetic declination for macedonia with a value of 2.7°. sediments are not older than 780 ka (brunhes chron) as also indicated by the radiometric age of the underlying flowstone. the distribution of the ms on the studied profile can indicate changes in deposition as well as the change of external climatic conditions. considering that the clastic sequence follows the mis 5a flowstone, it is assumed to be deposited during the mis 4 stadial (fig. 9c). lacustrine deposits of that age from the ohrid lake (belmecheri et al., 2010; lezine et al., 2010) record a gene­ rally cold and dry climate. the budimirica fill indicates chang­ ing climatic conditions with several relatively short­lasting but quite massive floods reflecting most probably highly fluctuating periodic precipitation rates. the deposits are eroded below the paragenetic ceiling and covered with the top flowstone, indicating another change of the depositional environment, towards a rather slower low­volume water flow (fig. 9d). the top flowstone was likely deposited dur­ ing the mis 3 interstadial, as it follows the mis 4 clastic se­ quence and is followed by strong erosion overlain with mis 2 deposits. the ohrid lake sediments (belmecheri et al., 2009, 2010) registered the mis 3 warmer and wetter climate ex­ cursion at 45–50 ka. the whole flowstone-clastic sediments-flowstone sequence was then deeply eroded and the cave fill was exhumed extensively (fig. 9e), likely by the invasion(s) of allogenic waters triggered by the strong incision of the kamenica valley, continuing water table fall, and change of environmental conditions during the mis 2 stage. the deep erosion of both clastic sediments and the topmost flowstone was followed by the deposition of fossil-bearing brec­ cia close to the cave entrance (fig. 9f). angular limestone frag­ ments in the breccia deposit represent the products of frost shat­ tering of cave walls especially at and near the cave entrance. this can be a result of both climate deterioration and enlargement of the cave entrance due to slope retreat in the valley, which corre­ lates well with the strong incision of the kamenica valley indi­ cated by the previous erosion of cave sediments. among several other bones, two teeth belong to ursus spelaeus (r. garevski, pers. comm., 2012; j. wagner, pers. comm., 2013), which can be compared with late weichselian (wurmian 2/3 and wurmian 3) bear remains from the makarovec cave located in the babuna valley in a neighbouring basin to the north of the studied cave (fig. 1); garevski (1969) and garevski & malez (1984). therefore the breccia can be attributed to the latest cold period of the weichselian glaciation (mis 2). ohrid lake sediments in­ dicate unstable environmental conditions during this period with a fluctuation of precipitation and temperature (lezine et al., 2010). the top organogenic deposits are likely due to recent (holocene) pasturage and represent sheep and/or cow coprolites (fig. 9g). 4.2. valley incision and aggradation the clastic deposition (as well as associated paragenetic morpho­ logy) in budimirica cave correlates with the remnant of a river terrace located in the gorge­like kamenica valley opposite the cave (fig. 10), at an elevation of 395 m (80 m above the present kamenica river) indicating river aggradation. it was previously considered (temovski, 2016) to belong to the same aggrada­ tion registered further upstream by a terrace in the middle part of the kamenica valley (and the clastic sediments in the temna peštera – dragožel cave), with the terrace (and the cave) located at the same relative elevation (figs. 2 and 10), 80 m above the present kamenica river. preliminary u-series dating of the flow­ stone covering the clastic sequence in temna peštera – dragožel gave an age older than 350 ka (h. hercman, per comm., 2015), dating the terrace as much older than the one at budimirica cave, thus indicating stronger erosion and/or uplift in the lower part of the kamenica valley. the river aggradation corresponding to the terrace at bu­ dimirica cave is attributed to the mis 4 glacial stadial, with a cold climate affecting vegetation cover and soil activity, which figure 10. longitudinal profile along the lower and middle part of the kamenica valley, showing locations of caves, river terraces, knickpoint positions and inferred valley incision rates. g eologia c roatica temovski et al.: a cave response to environmental changes in the late pleistocene: a study of budimirica cave sediments, macedonia 315 increases the erosion potential in the basin. this was likely rein­ forced by the seasonality of precipitation and runoff, thus increas­ ing sediment productivity and forcing aggradation of the river valley. such conditions (enhanced erosion) were also registered in the drainage basin of the ohrid lake during the late pleis­ tocene cold stadials (lezine et al., 2010). the longitudinal profile along the kamenica valley shows several knickpoints (sharp changes in channel slope; fig. 10). one is located a little upstream from temna peštera – dragožel, at the contact of the limestone and flysch, and is fixed (structurally and hydrologically), with the upstream karst system discharging along the contact and providing an increase in river potential for erosion. another (fixed) one is downstream from the budimirica cave, along the fault at the contact of the flysch and limestone, and may also indicate uplift of the limestone block. a third knick­ point can be noticed a little upstream from the limestone block where the budimirica cave is developed. the location of this knickpoint (not at the contact of limestone and flysch, but further upstream, in the flysch) and the higher river gradient in the lime­ stone block indicates headward retreat of the knickpoint, and thus stronger downstream erosion, which could be responsible for the strong erosion registered in the budimirica cave during the mis 2. such strong erosion is also indicated by the average incision rate of the kamenica valley based on the radiometric ages of the flowstone deposits in the budimirica cave and temna peštera – dragožel (fig. 10). the bottom flowstone in the budimirica cave sediment profile (dated at ca 83 ka) was deposited when the water table was a few metres lower than the cave (~395 m), and thus with relative elevation of 80 m above the kamenica river, this gives an average incision rate of ~0.96 mm.y­1 for the last 83 ka. in the middle part of the kamenica valley, at temna peštera – dragožel, the upper flowstone (covering the clastic deposits), which is at least 350 ka old (and follows previous aggradation), points to (a maximum) average incision rate of 0.23 mm.y­1. this value is almost five times smaller than that below the budimirica cave, although it represents a longer period (which could also in­ clude longer periods of incision paucity and/or aggradations). however, the incision in the lower part is still quite high, and cor­ relates well with the strong erosion registered in the budimirica cave sediments. 5. conclusion cave deposits preserved in the budimirica cave reflect the re­ sponse of the cave system to the environmental changes in the drainage basin. the budimirica cave is part of a contact karst system receiving both allogenic and autogenic recharge. incision of the kamenica valley lowered the water table and allowed de­ position of flowstone under vadose conditions during the mis 5a. flowstone deposits were covered by allogenic clastic sediments, originating from the weathered profiles of pyroclastic sediments of the plio-pleistocene vitačevo and mariovo formations. they were deposited in the cave in several floods as a result of the in­ crease of sediment supply and a base level rise due to aggradation in the kamenica valley in the mis 4, which also forced upward paragenetic development of the cave. continuing incision of the kamenica valley allowed erosion of the upper part of the clastic sequence and deposition of the upper flowstone deposits during the mis 3, followed by strong erosion during mis 2 as a result of fast incision triggered by river knickpoint retreat. this influenced enlargement of the entrance by slope retreat and deposition of fossil bearing breccia due to frost shattering during the cold sta­ dial. recent holocene input is restricted to human pasturage in­ fluence with deposition of organogenic deposits. the interpreted evolution of the cave deposits indicates that flowstone deposition corresponds to glacial interstadials (mis 5a and mis 3), and clastic sediment deposition corresponds to gla­ cial stadials (mis 4 and mis 2). cold periods affect vegetation cover and soil activity, which together with the seasonality of pre­ cipitation increases erosion in the basin, and the increase of sedi­ ment productivity forces aggradation in the valley, which also affected the cave development. the warm and wet climate of the interstadials, supports vegetation productivity and soil develop­ ment, which reduces erosion and sediment supply, and allows speleothem deposition in the cave. the general trend of incision in the kamenica valley was hindered due to climate induced aggradation during the mis 4, but continued during mis 3 and was reinforced by knickpoint retreat during mis 2. this change also affected the cave, with incision lowering the water table and influencing erosion of the cave sediments. dating of the changes in the kamenica valley registered in cave sediments from the budimirica cave gives information about valley incision rates along the kamenica valley, with high incision rates in the lower part of the kamenica valley being in agreement with the inferred incision rates of quaternary valleys in the mountainous areas of macedonia (milevski & kolča-kolča­ kovski, 2012). acknowledgement we would like to thank darko nedanoski for helping with the sampling. the palaeomagnetic analysis (jiří petráček and kristýna čížková), evaluation and preparation of the paper were carried out in the institute of geology of the cas, v. v. i. and supported by the plan of the institutional financing no. rvo67985831 (2012–2017). part of the preparation of the paper was carried out at the hertelendi laboratory of environmental studies (mta atomki), supported by mta postdoctoral fellow­ ship programme, no. pp-030/2015 (2015–2017). we also wish to thank the reviewers for their constructive comments. references arsovski, m. (1997): tektonika na makedonija.– rudarsko­geološki fakultet, štip, 360 p. belmecheri, s., namiotko, t., robert, c., von grafenstein, u. & dani­ elopol, d.l. (2009): climate controlled ostracods preservation in lake ohrid (albania, macedonia).– palaeogeography, palaeoclimatology, palaeoecology, 277, 236–245. doi:10.1016/j.palaeo.2009.04.013 belmecheri, s., von grafenstein, u., andersen, n., eymard­bor­ s., von grafenstein, u., andersen, n., eymard­bor­s., von grafenstein, u., andersen, n., eymard­bor­ u., andersen, n., eymard­bor­u., andersen, n., eymard­bor­ n., eymard­bor­n., eymard­bor­ don, a., régnier, d., grenier, ch. & lézine, a.­m. (2010): ostracod­ based isotope record from lake ohrid (balkan peninsula) over the last 140 ka.– quaternary science reviews, 29, 3894–3904. doi:10.1016/j.quascirev.2010.09.011 bosák, p., hercman, h., mihevc, a. & pruner, p. (2002): high resolution magnetostratigraphy of speleothems from snežna jama, kamniške-savinja alps, slovenia.– acta carsologica, 31/3, 15–32. bosák, p., pruner, p., mihevc, a. & zupan hajna, n. (2000): magnetostrati­ graphy and unconformities in cave sediments: case study from the classical karst, sw slovenia.– geologos, 5, 13–30. bosch, r.f. & white, w.b. (2004): lithofacies and transport of clastic sediments in karstic aquifer.– in: sasowski, i.d. & mylroie, j. (eds.): studies of cave sediments. physical and chemical records of paleoclimate. kluwer academic/ plenum publishers, 1–22. bull, p.a. (1981): some fine-grained sedimentation phenomena in caves.– earth sur­ face processes and landforms, 6/1, 11–22. dumurdžanov, n., hristov, s., pavlovski, b. & ivanova, v. (1976): ex­ planatory notes for the general geological map of vitolište and kajmakčalan, 1:100000 (in macedonian).– federal geological survey, belgrade, 61 p. g eo lo gi a c ro at ic a geologia croatica 69/3316 dumurdžanov, n., serafimovski, t. & burchfiel, b.c. (2004): evolution of the neogene-pleistocene basins of macedonia.– geological society of ameri­ ca. digital map and chart series, 1, 1–20. dumurdžanov, n., serafimovski, t. & burchfiel, b.c. (2005): cenozoic tectonics of macedonia and its relation to the south balkan extensional regime.– geosphere, 1, 1–22. fairchild, i.j. & baker, a. (2012): speleothem science. from process to past en­ vironments.– wiley­blackwell, chichester, 432 p. fisher, r. (1953): dispersion on a sphere.– proceedings of the royal society, a 217, 295–305. ford, d.c. & williams, p.w. (2007): karst hydrology and geomorphology.– wi­ ley, chichester, 562 p. garevski, r. (1969): stratigrafsko i paleontološko značenje na pleistocenskata fauna od pešterata makarovec vo klisurata na rekata babuna vo okolinata na titov ve­ les.– prirodonaučen muzej skopje, 6, 1–70. garevski, r. & malez, m. (1984): kvartarna fauna vertebrate iz spiljskih naslaga makedonije.– deveti jugoslovenski speleološki kongres, zagreb, 667–680. geološki zavod­skopje: geological map 1:25000, sheets: begnište, bošava, po­ loško, šeškovo (unpublished). gorka, p. & hercman, h. (2002): uranothor v. 2.5. delphi code of calcula­ tion program and user guide: ms.– archive of quaternary geology department, institute of geological sciences, pas, warsaw, 65 p. häuselmann, ph., lauritzen, s­e., jeannin, p­y & monbaron, m. (2008): glacier advances during the last 400 ka as evidenced in st. beatus caves (be, switzerland).– quaternary international, 189, 173–189. häuselmann, ph., mihevc, a., pruner, p., horáček, i., čermák, s., hercman, h., sahy, d., fiebig, m., zupan hajna, n. & bosák, p. (2015): snežna jama (slovenia): interdisciplinary dating of cave sediments and implication for landscape evolution.– geomorphology, 247, 10–24. doi: 10.1016/ j.geomorph. 2014.12.034 horáček, i. & ložek, v. (1988): palaeozoology and the mid-european quaternary past: scope of the approach and selected results.– rozpravy československé akademie věd, řada matematických a přírodních věd, 98/4, 1–102. hristov, s., karajovanović, m. & stračkov, m. (1965): explanatory notes for the general geological map of kavadarci, 1:100000.– federal geological sur­ vey, belgrade, 62 p. (in macedonian) ivanovich, m. & harmon, r.s. (1992): uranium series disequilibrium. applica­ tions to environmental problems. 2nd ed.– clarendon, oxford, 910 p. jelínek, v. (1966): a high sensitivity spinner magnetometer.– studia geophysica et geodaetica, 10, 58–78. jelínek, v. (1973): precision a.c. bridge set for measuring magnetic susceptibility and its anisotropy.– studia geophysica et geodaetica, 17, 36–48. kirschvink, j.l. (1980): the least­squares line and plane and the analysis of palaeo­ magnetic data.– geophysical journal of the royal astronomical society, 62, 699–718. kukla, j. & ložek, v. (1958): k problematice výzkumu jeskynních výplní.– česko& ložek, v. (1958): k problematice výzkumu jeskynních výplní.– česko­ slovenský kras, 11, 19–59. lacey, j.h., leng, m.j., francke, a., sloane, h.k., milodowski, a., vogel, h., baumgarten, h., zanchetta, g. & wagner, b. (2016): northern mediterranean climate since the middle pleistocene: a 637 ka stable isotope record from lake ohrid (albania/macedonia).– biogeosciences, 13, 1801–1820. doi:10.5194/bg-13-1801-2016 lascu, i. & feinberg, j.m. (2011): speleothem magnetism.– quaternary science reviews, 30/23–24, 3306–3320. lézine, a.­m., von grafenstein, u., andersen, n., belmecheri, s., bordon, a., caron, b., cazet, j.­p., erlenkeuser, h., fouache, e., grenier, c., huntsman­mapila, p., hureau­mazaudier, d., manelli, d., mazaud, a., robert, c., sulpizio, r., tiercelin, j.­j., zanchetta, g. & zeqollari, z. (2010): lake ohrid, albania, provides an exceptional multi-proxy record of environmental changes during the last glacial– interglacial cycle.– palaeogeography, palaeoclimatology, palaeoecology, 287, 116–127. doi: 10.1016/j.palaeo.2010.01.016 manakovik, d. (1971): podzemni karstni oblici vo porečieto na kamenica so kars­ na hidrografija.– godišen zbornik, geografski institut, skopje, 19, 41–59. (in ma-godišen zbornik, geografski institut, skopje, 19, 41–59. (in ma-in ma­ cedonian) milevski, i. & kolčakovski, d. (2012): recent landform evolution in macedo-kolčakovski, d. (2012): recent landform evolution in macedo-012): recent landform evolution in macedo­ nia.– in: loczy, d., stankoviansky, m. & kotarba, a. (eds.): recent landform evolution. the carpatho-balkan-dinaric region.– springer, 413–442. příhoda, k., krs, m., pešina, b. & bláha, j. (1989): mavacs – a new system creating a nonmagnetic environment for palaeomagnetic studies.– cuadernos de geologica ibérica, 12, 223–250. rakićević, t. & pendžerkovski, j. (1970): explanatory notes for the general geological map of kožuf, 1:100000.– federal geological survey, belgrade, 47 p. (in macedonian) rakićević, t., stojanov, r. & arsovski, m. (1965): explanatory notes for the general geological map of prilep 1:100000.– federal geological survey, bel­ grade, 65 p. (in macedonian) sasowski, i.d. & mylroie, j. (2004): studies of cave sediments. physical and chemical records of paleoclimate.– kluwer academic / plenum publishers, 329 p. sroubek, p., diehl, j.f., kadlec, j. & valoch, k. (2001): a late pleistocene palaeoclimate record based on mineral magnetic properties of the entrance facies sediments of kulna cave, czech republic.– geophysical journal international, 147, 247–262. temovski, m. (2016): evolution of karst in the lower part of crna reka river basin.– springer, 265 p. vojnogeografski institut (1973): topographic maps 1:25000, sheets prilep and demir kapija, beograd. zupan hajna, n., mihevc, a., pruner, p. & bosák, p. (2008): palaeomagne­ tism and magnetostratigraphy of karst sediments in slovenia.– založba zrc sa­ zu, postojna–ljubljana, carsologica, 8, 266 p. zupan hajna, n., mihevc, a., pruner, p. & bosák, p. (2010): palaeomagne­ tic research on karst sediments in slovenia.– international journal of speleology, 39/2, 47–60. geologia croaticageologia croatica application of groundwater modeling for designing a dewatering system: case study of the buvač open cast mine, bosnia and herzegovina  dušan polomčić and dragoljub bajić department of hydrogeology, faculty of mining and geology, university of belgrade, belgrade, djusina 7, serbia; (osljane@orion.rs) doi:10.4154/gc.2015.07 abstract this paper presents groundwater management based on the results of groundwater modeling. model used to simulate the effects of the operation of three dewatering system scenarios of the buvač open cast mine. several aquifers exist within the region of the buvač limonite ore deposit, which puts ore exploitation at risk due to water ingress. groundwater modeling was used to understand the groundwater regime within these aquifers. a previous numerical model (2007) was completed for the state of the groundwater regime prior to the opening of the open-cast mine. in the last five years, development of the open cast mine and associated activities have drastically modified the flow field. the model was modified for the altered conditions on site, and with new data from monitoring both the ground and surface water regimes. the existing system of protection of the cast mine from groundwater encompasses drainage of both the alluvial and ore body aquifers. this paper analyzes three scenarios for protecting the opencast mine from groundwater between 2013 – 2024. the new model was used to simulate the effects of operating the three proposed dewatering systems. differences in the operating effects of the scenarios were quantified through the conditions of groundwater levels and water budget. recommendations have also been given for performing prediction calculations in the case of the existence of drainage wells, with the most effective dewatering system determined from a hydrodynamic aspect. the results presented may be used for developing an effective dewatering system. keywords: numerical modeling, groundwater management, mine dewatering, bosnia and herzegovina 2000; li et al., 2014). these solutions were often developed based on simplified assumptions and boundary conditions that restrict their applicability in real world mining situations. numerical modeling codes such as modflow (harbaugh et al., 2000) enable finding solutions to significant regional groundwater problems and are very important for the design of dewatering systems for open cast mines. numerical models do not have the limitations of analytical solutions and are suitable for the simulation of all aquifer conditions (rapantova et al., 2007; polomčić et al., 2013b). for example, boskidisa et al. (2012) describe the use of modflow to examine several alternative scenarios for 1. introduction groundwater ingress into a mine during its operative life is one of the most important mining concerns. it is therefore necessary to quantify groundwater inflow into the mine and the effectiveness of the dewatering system in operation. prior to the development of computational numerical modeling methods, groundwater impacts were predicted by analytical and empirical methods, or hard-won experience. many analytical solutions for predicting water inflow into mine excavations can be found in the literature (hanna et al., 1994; marinelli & niccoli, 2000; shevenell, geologia croatica 68/2 123–137 11 figs. 2 tabs. zagreb 2015 mailto:osljane@orion.rs geologia croatica 68/2geologia croatica 124 the study area encompasses the wider region of the buvač open cast mine. in order to design a dewatering system, a numerical model of the open cast mine (polomčić et al., 2013a) was constructed when the mine was opened in 2007, with input data from the period 1971-1973. the use of data available from the beginning of the 1970s decreased the model’s reliability; however, these were the only data available at the time of model construction. from october 2010 to october 2012, new hydrogeological research and groundwater monitoring was conducted. in the meantime, from 2008, ore exploitation commenced at the open cast mine. as one of the measures of protection of the open cast mine from groundwater and surface water, the rivers gomjenica and bistrica were diverted into the new river bed of the river gomjenica, to the north of the mine (figure 1). the first numerical model was corrected and adjusted to the new conditions in the study area. new data regarding the site have enabled certain improvements to be made in assigning boundary conditions in the model. the model was supplemented with a set of the new registered data on the groundwater and surface water regimes. a new recalibrated model was used to simulate the operational effects of the dewatering systems from 2013 2024, i.e. until the end of ore exploitation. in total, three scenarios operating different dewatering systems were analyzed. the most efficient system, from a hydrodynamic perspective, was chosen by comparing the predicted operational effects. groundwater extraction from two aquifers, and describe how the calibrated model allowed for better management of groundwater resources. mylopoulosa et al. (2007) described an integrated water resources management plan wherein a numerical groundwater model of a deep aquifer system was used to develop alternative exploitation plans for the deeper aquifer. dewatering systems should also be designed and constructed to fully protect groundwater and surface water from mining impacts, to enable the sustainable extraction of ore. the new age of numerical analysis has enabled modeling of increasingly complex hydrogeological regimes and inclusion of components such as dewatering systems, drainage wells, and cut-off walls (strzodka & fischer, 1988; šubaranović et al., 2013). numerical models are most often used for open cast mines in order to determine the inflow of water into the mine workings (brawner, 1982), for assistance in designing dewatering systems (struzina et al., 2011; bahrami et al., 2014) or in order to analyze the effects and optimization of operating several possible dewatering systems (wu et al., 2010; jiang et al., 2013). they are also used to analyze the environmental impact of mining activities (wu et al. 2000, qiao et al., 2011; marandi et al., 2013) or to predict groundwater mounding after ore exploitation and dewatering system operation ends (banks et al., 2010; gödeke, 2011). figure 1: location and test borehole map of the study area. polomčić and bajić: application of groundwater modeling for designing a dewatering system: case study of the buvač open cast mine, bosnia and herzegovina geologia croatica 125 due to the changed conditions in exploration area, because of the mine dewatering and the beginning of mining, recalibrating of the first model was done (polomčić et al., 2013). additional advantages of the recalibrated model, compared to the first model, arise from the following facts: • more recent detailed exploration, which included expansion of the observation network of piezometers, resulted in a better understanding of the groundwater regime • the model was calibrated both manually and automatically, using pest (doherty & hunt, 2010) software, and the hydraulic properties which constituted model inputs were thus optimized. this contributed to a more efficient and more reliable approach to groundwater modeling and, as a result, recalibration of the new model was implemented at a higher level than that of the first model (polomčić et al., 2013a). 2. the hydrogeological setting of the study area the buvač limonite ore deposit (figure 1) is located in bosnia and herzegovina. it belongs to the northeastern part of figure 2: a) hydrogeological cross-section a-a’ (profile line in fig. 1) and b) 3d aquifer model in the study area. geologia croatica 68/2geologia croatica 126 the ljubija metallogenic province and occupies the southeastern peripheral area of the omarska mineral ore deposits which, in addition to the buvač mine, comprise the open cast mines of jezero and mamuze, (separated by about 500 m). the omarska ore deposits lie in a morphological depression of the omarska-prijedor field, which trends se-nw and is about 5 10 km wide and bout 20 km long. the slopes of mt. kozara, which separates the prijedor gorge from the sava valley and the lower end of the pannonian basin, constitute the northern boundary of the omarska-prijedor field. along the southern, southwestern and northern perimeters, the terrain continuously rises gradually to mt. grmeč, on the left bank of the sana river, and mt. menjača on the right bank of the sana river. the terrain is open to the north. the deposit is of carboniferous age and extends over an area of about 3000 m2 with an average thickness of about 20 m. the ore body is oriented northeast-southwest with a dip towards the northeast. it lies very close to the surface on the southwest side, while on the northeast side it is located at a depth of about 170 m (figure 2a). the lithological characteristics were determined based on core logging in more than 550 boreholes (figure 1). from a hydrogeological perspective, the basic characteristic of the study area is the variability of hydraulic conductivity with depth. within the study area, there are four types of aquifers: a quaternary alluvial aquifer, another in pliocene sands, an aquifer within the limonite ore body, and a confined karst aquifer located at the bottom of the ore body. the interrelationship between these aquifers is shown in the hydrogeological cross-section a-a’ (figure 2a) and in the 3d aquifer model (figure 2b). the alluvial aquifer is formed in alluvial sediments (quaternary gravels) of the river gomjenica and its tributaries. this aquifer is unconfined, and there is good evidence that it is connected hydraulically with the river, as shown in fluctuations in the gomjenica stages and the water table of the alluvial aquifer (polomčić et al., 2013a, fig. 6). groundwater recharge of the alluvial aquifer takes place through infiltration of precipitation and river water. the pliocene sands aquifer is mostly confined and receives recharge from outside of the boundaries of the ore body, on the northern edge of the study area. the ore body aquifer was formed in limonites which are characterized by significant porosity and water content. besides the alluvial aquifer, this is the most significant aquifer in the study area in terms of dewatering. the hydraulic link between the ore body aquifer and the river gomjenica was shown by polomčić et al., (2013a, fig. 7). groundwater in the limonite ore body is indirectly recharged by groundwater from the alluvial deposits, where they come into contact, and also from the karst aquifer at the bottom of the ore body. the hydraulic link between the ore body aquifer and the alluvial aquifer is shown in figure 3. the correlation coefficients between groundwater levels of alluvial aquifer and ore body aquifer indicate a very strong link (r2=0.95). the karst aquifer is a confined aquifer (polomčić et al., 2013a) and formed in carboniferous limestones and dolomites. it is not significantly water bearing and discharges directly into the limonite ore body in places where these two aquifers are in direct hydraulic contact (bajić & polomčić, 2008). based on the above, it can be concluded that there is a hydraulic link between all the aquifers. additionally, the objective of chemical analyses (bajić & polomčić, 2008) was to provide evidence of such a link between all aquifers in the buvač mine area. these analyses also indicated that the groundwater in the study area belongs to the hydrocarbonate class, ca type. the aquitards are dominated by quaternary sandy clays, pliocene clays and carboniferous altered siltstone, sandstone and compact calcite. sandy clays make up the northern periphery of the omarska-prijedor field, above an altitude of 160 m. they constitute the first and second palaeoterraces of the gomjenica river and overlie pliocene strata. the pliocene clays along the southern and northern edges of the field are extensive and lie directly on top of palaeozoic sediments. the thickness of these clays range from 10 60 m. pliocene clays also constitute a large proportion of the mining field, apart from the dominant carboniferous altered siltstone. these impermeable layers are lateral barriers to the groundwater in limestones. the floor of the ore body is also made up of impermeable rocks – carboniferous altered siltstone, sandstone and compact calcite (figure 2a). the beginning of ore exploitation in the buvač mine in 2008 had permanently and irreversibly altered the original hydrogeological and hydrological conditions in the study area. between 2008–2012 the dewatering system for protection of the open cast mine from groundwater inflow consisted of 8 wells in the alluvial aquifer and 7 wells in the ore body aquifer. there is also a significant number of piezometers – more than 20 which provide data on the groundwater heads. in 2009, the river beds of the river gomjenica and river bistrica were diverted into a new river bed with a length of 2,919 m, a width of 20 m with a bank inclination of 1:2. the figure 3: correlation dependence between groundwater levels of alluvial aquifer (a) and ore body aquifer (b) polomčić and bajić: application of groundwater modeling for designing a dewatering system: case study of the buvač open cast mine, bosnia and herzegovina geologia croatica 127 river bed elevations range from 156.3 to 153.63 m.a.s.l., and the general river bed slope is i=0.0011 %. the diverted river bed is designed for 100 year maximum water levels, and a protective levee was constructed on the left bank which is 1 m higher than the 100 year water level. the new river bed and the natural river beds of the river gomjenica and river bistrica are shown in figure 1. 3. numerical model (methodology) the conceptual model is based on the geological information obtained from boreholes (figure 1) and water-level data from observation wells. the model schematization includes a surface clay layer and a basal argillic siltstone of low permeability and an interbedded sequence of aquitards and four aquifers (polomčić et al. 2013a). the system is modeled using eight layers. the model layer characteristics are given in table 1. except for the overlying clays and alluvial gravels and sands, there is no lithological unit with continuous distribution in one model layer. table 1 shows lithological units which are present in each of the model layers. the hydraulic characteristics shown were derived from numerous research works and used in designing the first model (polomčić et al. 2013a). the three-dimensional finite-difference numerical model for this study was developed using modflow (harbaugh, 2000) with groundwater vistas as a graphical user interface (rumbaugh & rumbaugh, 2011). the model domain is 2260 × 2040, and 175 m in depth. the domain is oriented north-south and discretized into 102 rows, 113 columns, and 8 layers, with 85.425 active cells. the cell size of the flow field discretization in plan is 20 m × 20 m this was deemed a reasonable size given the number and quality of available data. the hydraulic characteristics of the model layers were assigned based on the hydraulic conductivity and specific storage values (table 1) that were previously determined during well testing in the open cast mine (polomčić et al., 2013a). the previous numerical model of the buvač open cast mine was updated to reflect the current condition of the mining works and the diversion of the river gomjenica, and supplemented with new data of the groundwater regime from october 2010 – october 2012. 3.1. boundary and initial conditions a head-dependent flux boundary condition (cauchy’s or mixed boundary condition) and a boundary of prescribed flux (neumann boundary condition) were used in the model. the effect of the diverted course of the river was simulated with the head-dependent flux boundary. in the modflow code, this simulation was performed using the river boundary condition and it was assigned in the first and second model layer (figure 4a) with water level values for the period from 1 october 2010 to 15 october 2012 (figure 5a). all geometric characteristics of the new river bed of the river gomjenica were incorporated into this type of boundary condition. the initial thickness of the sediment on the river bed bottom was assigned a value of 0.1 m, with an initial value of the hydraulic coefficient of the river sediment table 1: model layers and initial values of hydraulic parameters. model layer lithostratigraphic unit hydraulic conductivity (at x,y-axis) (m/s) hydraulic conductivity (at z-axis) (m/s) specific storage (1/m) specific yield 1 clay overburden 8.50x10–7–1.00x10–6 1.00x10–6 0.001 0.037 2 alluvial gravel and sandy gravel 1.40x10–4–3.80x10–4 1.00x10–4 2.25x10–5 0.225 3 clay and sandy clay 6.20x10–6–2.00x10–5 1.00x10–6 5.00x10–5 0.06 part of ore body 2.30x10–4 – 6.00x10–5 0.06 4 clay and sandy clay 5.00x10–6 1.00x10–6 5.00x10–5 0.06 sand and gravel 1.00x10–4–1.40x10–4 1.00x10–4 2.25x10–5 0.23 part of ore body 2.3x10–4 1.00x10–4 6.00x10–5 0.06 5 clay and sandy clay 4.0x10–6 1.00x10–6 5.00x10–5 0.06 part of ore body 2.3x10–4 1.00x10–4 6.00x10–5 0.06 6 argillic siltstone and sandstone 1.00x10–6 1.00x10–6 6.30x10–5 0.06 part of ore body 2.3x10–4 1.00x10–4 6.00x10–5 0.06 7 limonite and fine limonite 5.0x10–5–2.40x10–4 1.00x10–6 5.00x10–5 0.06 argillic siltstone and sandstone 1.5x10–5 1.00x10–6 6.30x10–5 0.06 limonite ore body 2.3x10–4 1.00x10–4 6.00x10–5 0.06 8 limestone and dolomitic limestone, siderite and ankerite in argillic siltstone and siltstone 3.52x10–4–4.70x10–4 2.50x10–4 6.30x10–5 0.06 argillically altered silstone and sandstone and compact calcite 1.00x10–7 1.00x10–7 6.30x10–5 0.06 geologia croatica 68/2geologia croatica 128 of 1x10-6 m/s. by assigning head-dependent flux boundary conditions, the model simulates groundwater inflow and outflow into the model. in the modflow code, this was represented with a general head boundary (ghb). in the alluvial aquifer to the east and west, this boundary condition simulates the outflow or inflow into the model which also generally follows the river gomjenica outside of the study area (figures 4 and 6). the ore body during the development of the mine had the role of a local base level of erosion towards which the surrounding groundwater gravitates. based on earlier research, and as a result of the first model (polomčić et al., 2013a), the existence of impermeable rocks in the south was determined, and the absence of significant inflow into the study area from the north. in the seventh model layer with the largest distribution of the ore body in the east and west, a general head boundary was assigned (figure 4b and figure 6). according to the layers shown in figure 2, in the karst aquifer (7) and the pliocene aquifer (4), the inflow into the model was assigned only in the northern contour of the study area. also, the ghb hydraulic conditions were taken from the first model (figure 6). the pliocene aquifer is much larger north of the model domain. the effect of that aquifer on the edges of the pliocene sands included in the model was specified via the ghb boundary condition, simulating inflow while keeping in mind the hypsometric positions of the recharge zone of this aquifer along the southern slopes of mt. kozara (north of the model domain). the karst aquifer was handled in a similar manner in the 8th model layer (table 1), which is represented in the central part of the model domain, while in the northernmost part it extends beyond the model domain. it was also assumed that it was part of a larger aquifer to the west, as it was detected in open cast mines west of study area. an additional problem was a lack of data as there are no piezometers in the pliocene and karst aquifers. figure 4: distribution map of piezometric levels (15 oct. 2012) in the alluvial aquifer (a) and levels in the ore body (b) and the boundary conditions in the open cast mine “buvač”. figure 5: an overview of groundwater levels: a) in the alluvial aquifer and b) in the limonite ore body in the period 1 october 2010 – 15 october 2012. polomčić and bajić: application of groundwater modeling for designing a dewatering system: case study of the buvač open cast mine, bosnia and herzegovina geologia croatica 129 figure 6: column (south-north) and row (west-east) cross section. the outer contours of the impermeable units (layers 3 – 8) are represented by a no-flow boundary condition (figure 6). initial heads for the karst aquifer and the pliocene aquifer, as there is no exact data, were based on the results of calibration of the first model (polomčić et al., 2013a). unpublished data were used for the initial heads of these aquifers in the first model, which were collected during the course of designing urban and rural water supply systems, at 10 km and 18 km northwest of the study area, respectively. based on the regional extent of the pliocene and karst aquifers, their hypsometric positions and the activities relating to the nearby water supply projects, the conclusion was that these aquifers are slightly pressurized. a total of 8 drainage wells were in operation in the buvač open cast mine from 1 october 2010 – 15 october 2012. the individual capacities of the wells ranged from 1-50 l/s, with a total capacity of 158 l/s. the locations of the wells in the area included in the model are shown in figure 4. the wells only drain the alluvial aquifer and the ore body aquifer. the wells were assigned a “prescribed flux” boundary condition. with this type of boundary condition, the case of no flow is also assigned (q=0), i.e. selected cells can be designated “no-flow” cells in the modflow code. these no flow cells represented zones where material has been excavated as a consequence of mining (figures 4). in nature, these zones are practically impermeable. the exception is a part of the excavated ore body the active surface of which is relatively small and continually changes with the dynamics of ore exploitation. along the working benches of the mine there are drainage canals that direct precipitation to a water collector and from there transfer the water by pumps into the river gomjenica, so the working area for ore exploitation is not at risk from run off. recharge is simulated by selecting the prescribed flux boundary condition in the first model layer only. this creates an influx as the difference between the total recharge and evapotranspiration. according to the 2007 model (polomčić et al., 2013a), the average infiltration was 15% of total precipitation; this value was used as an initial condition applied to precipitation for the period 1 october 2010 – 15 october 2012. the existing cut-off wall on the south and east side of the ore body (figure 4), and a new one, which was modeled in a number of the predictive option models as discussed later, is assumed to be composed of a cement-bentonite fill with a thickness of 1 m and hydraulic conductivity of 1 x 10-8 m/s. this feature was simulated with a prescribed flux boundary condition (neumann boundary condition), i.e. “wall” (flow barrier) in the modflow code. the proposed cut-off wall (figure 4), will extend through the entire alluvium layer down to 1 metre in clayey sediments, its geometric characteristics, as well as the characteristics of the infilling were assigned in the first and second model layer. 3.2. model recalibration the model was recalibrated under transient flow conditions, with a time step of one day (a total of 654 steps) for the period 1 october 2010 – 15 october 2012, which in the lower level of iteration was divided into 10 parts, of unequal duration (factor 1.2). measured piezometric levels in the alluvial aquifer (figure 5a) and in the limonite ore body aquifer (figure 5b) were used as calibration targets. figure 4 shows the plan location of the measuring points and the distribution of the piezometric levels in the alluvial aquifer and in the ore body as of 15 october 2012. gradually, over time, a certain geologia croatica 68/2geologia croatica 130 number of piezometers and wells (figure 5) were unusable due to the lowering of groundwater levels below their maximum depth. as a confirmation of the quality of the performed recalibration of the model, figure 7 shows the time series and calibration graph. results of the mathematical simulation of the groundwater regime, in relation to the registered groundwater levels, are in good agreement. the statistical indicators of the quality of model recalibration are: residual mean: -0.03, residual standard deviation: 0.09, absolute residual mean: 0.08; residual sum of squares: 0.15; rms error: 0.10; normalized rms 5.84 %; minimum residual: -0.22; maximum residual: 0.12. under the operating conditions of the dewatering wells system in the mine, a change in the flow conditions occurred i.e. intensified three-dimensional groundwater flow as a result of the diversion of the river gomjenica into a new river bed and the development of the mine. table 2 gives an overview of the basic elements of the groundwater water balance after model recalibration. in the alluvial aquifer, the predominant mode of recharge is water infiltration from the river gomjenica (78.17%). in relation to the first model (polomčić et al., 2013a) which was calibrated to conditions prevailing in 1973, river water recharge to the alluvial aquifer has increased due to the operation of drainage wells which have a total discharge of 158 l/s. the flow between the existing aquifers in the mine has also changed since 1973. model predicted inflows to the ore body from the alluvial aquifer and from the karst aquifer are 26.8 l/s and 8.3 l/s respectively. inflow to the ore body is greatest from the east, with less from the west. the total inflow into the ore body decreased by 40.1 l/s in relation to the quantities of water captured by wells, which confirms the successful drainage of the ore body up to this point (figure 5b). the balance of the pliocene aquifer is not significant for the total groundwater balance in the study area. inflow from the karst aquifer to the ore body aquifer is partially replenished by groundwater inflow from the north. 3.3 management scenarios the recalibrated groundwater model was used to evaluate options for water management for 2013–2024. calculations were based on sequential time steps; the result at the end of table 2: groundwater balance (15 october 2012). aquifer boundary condition inflow to model (l/s) outflow from model (l/s) alluvial aquifer and aquifer in pliocene sands effective infiltration 15.2 gomjenica river 97.4 ghb – east 2.3 ghb – west 9.7 drainage wells 22 migration into the ore body aquifer 26.8 the limonite ore body aquifer ghb – east 36.7 ghb – west 24.1 drainage wells 136 karst aquifer ghb – east 8.3 ghb – north 7.9 sum 193.3 193.1 figure 7: time series and calibration graph for the analyzed period (1 october 2010 – 15 october 2012): a) alluvial aquifer b) ore body aquifer. polomčić and bajić: application of groundwater modeling for designing a dewatering system: case study of the buvač open cast mine, bosnia and herzegovina geologia croatica 131 one time interval representing the initial condition for calculation in the next. the calculations were performed in a transient flow regime, using a month as the basic time interval for the calculation within one year. at the end of each year, in prognostic calculations, there has been increase in area of “no flow” cells as a result of the yearly advancement of the mining works – excavating the spoil and extracting the ore, and the development of analyzed dewatering systems. three groundwater management scenarios were modeled, as described later, and figure 8 shows the elements of the dewatering system in the „buvač“ open cast mine: on the day of recalibration of the hydrodynamic model (a), the dewatering system according to variant 1 (b), variant 2 (c), and variant 3 (d). all three scenarios were identical during 2013 and 2014, while for 2015 scenarios 2 and 3 are identical. from 2016, all scenarios are different and develop independently. for all three scenarios, the open cast development follows the planned mining activities until the end of 2024. all three management scenarios included the following features: • 8 existing drainage wells in the west that drain the alluvial aquifer, • the existing drainage channel du-4 in the alluvial aquifer; • starting from 01.01.2015 the gomjenica river is partly relocated to the new riverbed north of the mine; • the river gomjenica diversion; • the locations, initial capacities, and length of operation of drainage wells that primarily drain the ore body, and • the main mining criterion is that the groundwater level should be at least 15 metres below the working bench in the ore body. the drainage channel du-4 is assumed to be excavated to the bottom of the alluvial sands and gravels in the northern part of the mine, ahead of the mining. the channel will intercept groundwater which is not extracted by the wells. the water from the drainage channel flows to the water collector and is then returned to the river gomjenica. at the beginning of prognostic calculations, seven drainage wells are assumed in the ore body each with a capacity of 8-50 l/s, for a total capacity of 126 l/s. scenario 1 according to scenario 1, 33 additional wells in the alluvial aquifer to the north of the open cast will start on 1 january 2015, will increase the protection from river water seepage based on the 8 exisiting wells. the initial well capacities range from 2 l/s to 7 l/s (with a sum of 107 l/s) and are assumed to operate continually during the entire life of the mine, i.e. until the end of 2024. figure 8b shows the dewatering system according to variant 1. scenario 2 in scenario 2, instead of the 33 drainage wells, a dewatering system in the alluvial aquifer comprises a cut-off wall, almost 2000 m long and extending 1m into the clayey silty sediments below the alluvial sediments. the cut-off wall is assumed to be completed on 1 january 2016. figure 8c shows the dewatering system according to variant 2. scenario 3 scenario 3 represents a combination of the previous two scenarios. in the northwest part of the mine, where the open cast is closest to the river, a 1000 m long cut-off wall is assumed, similar to that described in scenario 2. the cut off starts near the existing well eb-8, and is assumed to be complete on 1 january 2016. continuing from the wall, 13 drainage wells are assumed to be constructed with the same characteristics and initial capacities as in scenario 1, for a total capacity of 65 l/s. the wells begin operation on 1 january 2017, and operate until the end of mining (2024). figure 8d illustrate this scenario. 4. results and discussion before analyzing the results of the simulation of different variants of the dewatering system, it should be noted that in bosnia and herzegovina, it is usual for projected mining works to be presented on a yearly state (31 december) during the first five years, and subsequently on a 5-year level with a projected final contour of the mine at the end of ore exploitation. the most significant change in the flow pattern in the wider area of the mine depends on the construction dynamics of the advancing excavation contour, given in 1-year time steps (at the end of the calendar year, 31 december). it is realistic for the mine advancement to be a linear continuous process. this applies especially to the overview of derived results per time interval viewed in 2022 (a fiveyear step of 2017-2022) and 2024 (a two-year step: 20222024). it is also necessary to provide an explanation, regarding the correct interpretation of the calculated results, which relates to the operation of drainage wells. the wells were assigned in the model using their discharge, for which the initial values represent one of the results of the prognostic calculations. the results of the calculations proved to be very sensitive to changes in initial well capacities, which must gradually decrease over time. otherwise, there is an excessive decrease in the piezometric head in the wells. if too large initial capacity were given, this would result in shutting down of the well. these facts primarily apply to the hydraulic characteristics of porous media. in the other hand, these are the consequences of the limits of the modflow finite difference model. first is, that it is a quasy 3d flow model. second, the hydraulic conductivity tensor is represented only with three principal components kxx, kyy and kzz perpendicular to the faces of the finite difference cells (horizontally rectangular). all of this is not representing in the best possible way 3d problems which occur in the vicinity of the pumping wells. the piezometric heads in the alluvial aquifer obtained for each scenario are shown in figures 9 (a, b) and 10 (a, b, c) and the piezometric heads in the ore body are shown in figures 9c and 10d, at the end of 2015 and 2024. over time, the operation of the drainage system, excavation of overburden and of the ore body, will lead to a geologia croatica 68/2geologia croatica 132 gradual lowering of the regional piezometric heads. during one years simulated operation of the drainage system, besides the “no flow” cells, (which are primarily a consequence of mining), “dry cells” appear in the model and expand in time due to the operation of the system. the protective influence of the system on groundwater ingress to the open cast mine is manifested by different gradients of hydraulic head both within and outwith the outer contours of the drainage system. in relation to 2013 and 2014, when the system in the alluvial aquifer consists only of the du-4 drainage channel (figures 9 and 10), there begins in 2015 or 2016, a significant change in the flow pattern for each of the three simulated dewatering systems. according to the first simulated scenario (figures 9a and 10a) for protection of the open cast mine, a total of 41 fully penetrating wells together with with the drainage channel du-4, compose the drainage system. the first scenario is the least effective, and results in the smallest decrease in groundwater levels ahead of mining. the second scenario (figures 9b and 10b) with a cut-off wall which prevents groundwater inflow through the alluvial sediments from the direction of the river gomjenica, very quickly results in dewatering of the alluvial deposits ahead of mine development, and causes the du-4 drainage channel to cease surface flow relatively quickly. over time, the “dried” surface spreads, while in the north-east of the mine a narrow zone remains along which there is inflow into the open cast mine, as the result of the flow of uncaptured groundwater between wells eb-1 to eb8. according to the achieved protective effects, this variant represents the most efficient defense from the inflow of groundwater into the open cast mine through the alluvial deposits. the third scenario (figures 9b and 10c) simulates the operation of the open cast mine protection system which is composed of the existing drainage wells eb-1 to eb-8 in the west, a cut-off wall in front of the open cast mine where the river bed of the river gomjenica is closest, the drainage wells eb-29 to eb-41 continuing after the wall in the north, as well as the du-4 drainage channel. the third scenario is a combination of the first and second scenarios and the impact on groundwater flow is intermediate between scenarios 1 and 2. figure 8: elements of the dewatering system in open pit mine „buvač“: on the day of re-calibration of the hydrodynamic model (a), the dewatering system according to variant 1 (b), variant 2 (c), and variant 3 (d). polomčić and bajić: application of groundwater modeling for designing a dewatering system: case study of the buvač open cast mine, bosnia and herzegovina geologia croatica 133 in terms of drainage of the ore body, an almost identical decrease in groundwater levels is predicted for all three of the analyzed scenarios (figures 9c and 10d), due to the identical drainage system in the ore body for each scenario. the obtained differences per scenario are only related to the capacities of the individual wells (figure 11). the decrease of groundwater levels in the ore body is, for all variants and for each analyzed year, below the working bench levels in the assigned values (a minimum of 15 metres below). the effects of the three scenarios are analyzed for the alluvial aquifer and for the ore body (figure 11) through comparisons of the predicted flow of the drainage wells. all three analyzed scenarios include a line of wells (eb-1 do eb8) in the west. in the first scenario, these wells have greater predicted flow than in scenarios 2 and 3, due to the absence of the cut-off wall. the maximum well capacity will be reached at the beginning of 2015 (158 l/s) and towards the end of the simulated period will decrease by 14%. in scenarios 2 and 3, the greatest differences in well flow occur in those wells closest to the cut-off wall, due to the restricted inflow of water to the wells. in scenarios 2 and 3, the predicted flows from wells in the west are 40% less at the end of the calculation period, in comparison to scenario 1. there is a similar occurrence in other wells close to the cut-off wall in scenario 3 (wells eb-29 and eb-30). in wells eb-38 to eb41 in variant 3, the proximity of the cut-off wall does not affect a significant decrease in the capacity of these wells, due to the proximity of the diverted river bed of the river gomjenica, and the small initial capacities of the wells. drainage channel du-4 is likely to be most effective in the first operational years of the model with an inflow of 38 l/s, where, apart from the drainage channel and drainage wells, there are no other facilities to protect the mine from groundwater inflow through the alluvium. the inflow into the channel varies between scenarios with the smallest flow predicted for scenario 2 (no inflow until january 2016) and the largest flow for scenario 1 (16 l/s in january 2016 to 5 l/s in september 2017). figure 9: the distribution of piezometric levels: a) in the alluvial aquifer at the end of 2015 (scenario 1), b) in the alluvial aquifer at the end of 2015 (scenario 2 and 3) and c) in the ore body at the end of 2015. geologia croatica 68/2geologia croatica 134 the differences between the scenarios in terms of water balance in the ore body are practically negligible and a single conclusion may be drawn for all three. a number of “bu wells”, even after a periodic reduction, are withdrawn from operation, due to the overall decrease in groundwater levels (figure 11). from the beginning of 2013 to the end of 2015, the total capacity of the wells in the ore body (bu wells) decreased by 13% (from 121 l/s to 105 l/s). a certain increase in the predicted flow (figure 11) of the wells in the ore body is due to the introduction of new wells (january 2016). from 2016 when the dewatering system in the ore body reaches the maximum capacity of 124 l/s, to the end of the prognostic period, there is a continual decline in well capacity as well as in mining activities, and the deactivation of a number of wells. at the end of 2024, the total well capacity is decreased by 68%. in the first three years the model predicts similar groundwater discharge into the pit of about 10–14 l/s with all scenarios showing similar inflow. the inflow reduces over the modeled period to about 6 10 l/s for scenario 1 and 3 6 l/s for scenario 2 with scenario 3 inflows being intermediate between the scenario 1 and scenario 2 inflows. 5. conclusion the exploitation of the limonite ore in the open cast mine buvač began at the end of 2008. new hydrogeological research and monitoring of the groundwater regime were performed to assist in the selection of groundwater management schemes for protection of the buvač open cast mine from groundwater inflow until the end of ore exploitation (2024). the numerical model provides a tool for predictive calculafigure 10: the distribution of piezometric levels: a) in the alluvial aquifer at the end of 2024 (scenario 1), b) in the alluvial aquifer at the end of 2024 (scenario 2), c) in the alluvial aquifer at the end of 2024 (scenario 3) and d) in the ore body at the end of 2024. polomčić and bajić: application of groundwater modeling for designing a dewatering system: case study of the buvač open cast mine, bosnia and herzegovina geologia croatica 135 tions to compare options for protection of the open cast mine from groundwater inflow. three groundwater management scenarios were modeled for the period from 2013 to 2024. the scenarios mainly differ in the methods of management of groundwater flow in the alluvial aquifer. in all of the analyzed scenarios of the dewatering system, the required drop of groundwater levels to more than 15 metres below the working bench in the ore body, has been achieved for every year in the prognostic calculations,. all the facilities protecting the open cast mine from water ingress via the diverted river bed of the river gomjenica are positioned parallel to the river course, north of the mine. scenario 1 models management of the alluvial flows by the use of a line of wells, while scenarios 2 and 3 include different numbers of wells and variable lengths of cut-off wall. the design and sequence of construction of the drainage wells in the ore body is the same for all options. all options show that groundwater inflow to the pit, and flow through the alluvial aquifer decreases as a consequence of the dewatering systems. the projected open cast mine contours are the primary basis for the analysis of the different dewatering systems. in bosnia and herzegovina, and in some of the former yugoslav states, it is usual to present projected mining works on a yearly state (year end) for the first five-year period, and then on a 5-year interval level, with a projected final open cast mine contour at the end of ore exploitation. likewise, after each five-year period of ore exploitation, the prognoses of the dewatering system operation are verified or corrected. the most significant change in the flow pattern in the wider area of the mine is influenced by the construction dynamics of the excavation contour advancement, which is presented with a time step of a minimum of one year, which differs from the real conditions when advancement of the mine is linear in process. as a reference position, the prognostic calculations adopted the condition of the mine contour at the end of the year (31 december) which is kept during the entire following year of calculations. more significant differences appear in 2022 (after five years) and in 2024 (after two years). besides this, in all the analyzed dewatering systems, the drainage wells have a significant role. during the calculations, the results proved to be very sensitive to changes in the initial values of well capacities, which must decrease gradually over time. otherwise, there is an excessive decrease in piezometric heads in the wells which results in wells either being shut down or showing an insufficient level of reduction in the wider area of the wells. therefore an especially sensitive task during prognostic calculations was assigning the discharge of the drainage wells, where several criteria and limits had to be kept in mind: • the initial well capacities should not be too large, as the dewatering effect which is aimed at will not be achieved – even with a steep decrease in the groundwater levels in a well, a corresponding drawdown does not form in the surrounding area. this is a not only a result of the hydraulic characteristics of the media (alluvial sediments and the limonite ore body), but also their variable thickness. • the life span of the wells which are located in the course of the mine advancement front, depends on the dynamics of the advancement of spoil excavation. over time, with the advancement of the spoil benches, the well gradually shortens and its capacity decreases, until the final shut down, i.e. destruction of the well. • the well discharge decreases correspondingly and simultaneously with the gradual drainage and decreasing groundwater levels. it is necessary to create a balance between the well discharge and level reduction, in the well itself and its immediate surroundings, as well as in the wider zone of the well. figure 11: a comparative diagram of the predicted total flow of drainage wells and in the du-4 channel (january 2013 – december 2024) for all scenarios where eb wells are in the alluvial aquifer and bu wells are in the ore body. geologia croatica 68/2geologia croatica 136 • a proportion of the wells in the ore body are not destroyed, remaining permanently in operation, and their capacities decrease over time. • a number of wells are removed from operation over time due to the decrease in groundwater levels below the elevation of the well screen construction. from a hydrodynamic aspect, scenario 2 which includes a cut-off wall ahead of mining of the north wall of the open cast mine provides the best protection from the inflow of groundwater from the alluvial aquifer from the direction of the diverted river bed of the river gomjenica. scenario 3 is a combination of the first and second scenarios, with a dewatering system composed of a shorter cut-off wall and drainage wells, and this is the second most effective option. a techno-economic analysis is required to select the best of the analyzed scenarios for protection of the open cast mine “buvač” from groundwater inflow. finally, it is concluded that the application of groundwater modeling has proven very useful in comparing methods for protection of the open cast mine from groundwater inflow. the hydrodynamic model of the aquifer regime and management scenarios for protection from groundwater inflow in the open cast mine “buvač” opens the way toward system optimization and sustainable economic development. acknowledgment our gratitude goes to the ministry of education, science and technological development of the republic of serbia for financing projects “oi176022“, „tr33039” and „iii43004“. two reviews, by kristijan posavec (zagreb, croatia) and an anonymous reviewer, are also acknowledged for their contribution and effort in providing constructive criticism and improving the manuscript. references bajić, d. & polomčić, d. (2008): 3d hydrogeological model of the limonite ore body “buvač” (republika srpska, bosnia and herzegovina). in proceedings of the iv international conference “coal 2008” held at belgrade, serbia, october 2008) – yugoslav opencast mining committee, 2008. bahrami, s., ardejani, f.d., aslani, s. & baafi, e. (2014): numerical modelling of the groundwater inflow to an advancing open pit mine: kolahdarvazeh pit, central iran.– environmental monitoring and assessment, doi: 10.1007/s10661-014-4025-x banks, d., frolik, a., gzyl, g. & rogoż, m. (2010): modeling and monitoring of mine water rebound in an abandoned coal mine complex: siersza mine, upper silesian coal basin, poland.– hydrogeology journal, 18/2, 519–534. doi: 10.1007/s10040-009-0534-z boskidisa, i., pisinarasa, v., petalasa, c. & tsihrintzisa, v.a. (2012): monitoring and modeling of two alluvial aquifers in lower nestos river basin, northern greece.– journal of environmental science and health, part a: toxic/hazardous substances and environmental engineering, 47/12, 1849–1868. doi: 10.1080/ 10934529.2012.689552 brawner, c.o. (1982): control of groundwater in surface mining.– mine water and the environment, 1/1, 1–16. doi: 10.1007/ bf02504603 doherty, e.j. & hunt, j.r. (2010): approaches to highly parameterized inversion: a guide to using pest for groundwater-model calibration.– u.s. geological survey scientific investigations report 2010-5169: reston, va, usa, 59 pp. gödeke, s. (2011): simulation of groundwater mounding at a west australian mine site.– environmental earth science, 64/5, 1363– 1373. doi: 10.1007/s12665-011-0961-8 hanna, t.m., azrag, e.a. & atkinson, l.c. (1994): use of an analytical solution for preliminary estimates of groundwater inflow to a pit.– mining engineering, 46/2, 149–152. harbaugh, a.w., banta, e.r., hill, m.c. & mcdonald, m.g. (2000): modflow-2000, the u.s. geological survey modular ground-water model: user guide to modularization concepts and the ground-water flow process.– u.s. geological survey openfile report 00-92: reston, va, usa, 121 p. jiang, s., kong, x., ye, h. & zhou, n. (2013): groundwater dewatering optimization in the shengli no. 1 open-pit coalmine, inner mongolia, china.– environmental earth science, 69, 187–196. doi: 10.1007/s12665-012-1946-y li, t., song, h., huang, g., bi, y. & li, h. (2014): assessment of groundwater changing trends through the generalized large well method with confined-unconfined flow model in open-pit mine area.– environmental earth science, doi: 10.1007/s12665-014-3357-8 marandi, a., karro, e., polikarpus, m., jõeleht, a., kohv, m., hang, t. & hiiemaa, h. (2013): simulation of the hydrogeologic effects of oil-shale mining on the neighbouring wetland water balance: case study in north-eastern estonia.– hydrogeology journal, 21/7, 1581–1591. doi: 10.1007/s10040-013-1032-x marinelli, f. & niccoli, w.l. (2000): simple analytical equations for estimating ground water inflow to a mine pit.– ground water, 38/2, 311–314. doi: 10.1111/j.1745-6584.2000.tb00342.x mylopoulosa, n., mylopoulosb, y., kolokythab, e. & tolikas, d. (2007): integrated water management plans for the restoration of lake koronia, greece.– water international, 32/1, 720–738. doi: 10.1080/02508060.2007.9671993 polomčić, d., bajić, d., papić, p. & stojković, j. (2013a): hydrodynamic model of the open-pit mine “buvač” (republic of srpska).– journal of sustainable development of energy, water and environment systems 1/3, 260–271. doi: 10.13044/j.sdewes.2013. 01.0019 polomčić, d., hajdin, b., stevanović, z., bajić, d. & hajdin, k. (2013b): groundwater management by riverbank filtration and an infiltration channel: the case of obrenovac, serbia.– hydrogeology journal, 21/7, 1519–1530. doi: 10.1007/s10040-0131025-9 qiao, x., li, g., li, m., zhou, j., du, j., du, c. & sun, z. (2011): influence of coal mining on regional karst groundwater system: a case study in west mountain area of taiyuan city, northern china.– environmental earth science, 64, 1525–1535. doi: 10.1007/s12665010-0586-3 rumbaugh, j.o. & rumbaugh, d.b. (2011): guide to using groundwater vistas: version 6. environmental simulations, new york. rapantova, n., grmela, a., vojtek, a., halir, j. & michalek, b. (2007): ground water flow modelling applications in mining hydrogeology.– mine water and the environment, 26/4, 264–270. doi: 10.1007/s10230-007-0017-1 shevenell, l. (2000): analytical method for predicting filling rates of mining pit lakes: example from the getchell mine, nevada.– mining engineering, 52/3, 53–60. struzina, m., mueller, m., drebenstedt, c., mansel, h. & jolas, p. (2011): dewatering of multi-aquifer unconsolidated polomčić and bajić: application of groundwater modeling for designing a dewatering system: case study of the buvač open cast mine, bosnia and herzegovina geologia croatica 137 rock opencast mines: alternative solutions with horizontal wells.– mine water and the environment, 30, 90–104. doi: 10.1007/ s10230-011-0149-1 strzodkaa, k. & fischera, m. (1988): dewatering wells and sealing walls for water control in lignite mines.– international journal of surface mining, reclamation and environment, 2/2, 105– 107, doi 10.1080/09208118808944143 šubaranović, t., pavlović, v., polomčić, d. (2013): influence on environment of sealing screen at lignite opencast mines.– metalurgia international, 18/5, 169–176. warner, j.w., khazaeib, w., warnerc, j., manghid, f., phranere, r.w., mortazavie, b. & namvarf, r. (2009): flow and transport modelling of a highly stressed aquifer to refine management strategies.– water international, 34/2, 264–279. doi: 10.1080/02508060902894622 wu, q., dong, d.l., shi, z.h., wu, x., sun, w.d., ye, g.j., li, s.w. & liu, j.t. (2000): optimum combination of water drainage, water supply and eco-environment protection in coal-accumulated basin of north china.– science in china series d: earth sciences, 43/2, 122–133, doi 10.1007/bf02878141 wu, q., hu, b.x., wan, l. & zheng, c. (2010): coal mine water management: optimization models and field application in north china. hydrological sciences journal, 55/4, 609–623. doi: 10.1080/02626661003798310 manuscript received december 08, 2014 revised manuscript accepted april 01, 2015 available online june 16, 2015 2019 | 72/2 | 145–162 | 10 figs. | 4 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction in serbia to date, encrustations have frequently been noted on the technical elements of mineral water wells (wellheads, screens, pumps, discharge pipes, and the like) (lazić, 2004), as well as within zones of emergence (protić, 1995; šaraba et al., 2017). encrustations are typical only of the upper part of the well casing, caused by a higher flow velocity in that region (houben & weihe, 2010). encrustations are precipitates of salts and alkalis, which most frequently takes place in mineral waters from aquifers with dis­ solved calcium, magnesium and iron. precipitation is the result of a change in ambient conditions (ph, temperature, pressure, solute concentration) due to mineral water pumping, which causes super­ macroscopic, optical and diffraction assessment of encrustations and sem analyses of phototrophic microbial mats from wellheads and select zones of emergence of mineral water in serbia vladimir šaraba1*, slađana popović2, vesna obradović3, jana štrbački1, violeta gajić4, predrag vulić4, gordana subakov simić5 and olivera krunić1 1 university of belgrade, faculty of mining and geology, department of hydrogeology, đušina 7, 11000 belgrade, serbia; (*corresponding author: vladimirsarabaa@gmail.com) 2 university of belgrade, institute of chemistry, technology and metallurgy, national institute, department of ecology and technoeconomics, njegoševa 12, 11000 belgrade, serbia 3 jaroslav černi water institute, jaroslava černog 80, 11000 belgrade, serbia 4 university of belgrade, faculty of mining and geology, department of mineralogy, crystallography, petrology and geochemistry, đušina 7, 11000 belgrade, serbia 5 university of belgrade, faculty of biology, department of algology, mycology and lichology, studentski trg 16, 11000 belgrade, serbia doi: 10.4154/gc.2019.09 abstract investigations focusing on wellhead encrustations within select zones of emergence of mineral water, in different hydrogeological provinces, were conducted from 2014 to 2017 in serbia. they included: well bb-1 in bogatić (inner dinaric alps of western serbia), wells lb-4 and lb-5 in lukovska banja (šumadija-kopaonik-kosovo province), and wells vg-2 and vg-3 in vranjska banja (serbian crystalline core). the studied occurrences belong to the group of hot mineral waters, with temperatures ranging from 62°c to 93.9°c, and total dissolved solids (tds) from 600 to 1267 mg/l. they are mildly acidic to mildly alkaline (ph 6.6 – 8.0) and their genetic types are hco3 --na++k+ (bogatić and lukovska banja) and so4 2-, hco3 --na++k+ (vranjska banja). macroscopic, optical and diffraction assessment revealed that the encrustations comprised calcite and aragonite minerals, along with some local quartz, muscovite, albite and clinochlore. the conclusion was that there was a predominant presence of calcium carbonate in all the occurrences, represented by crystalline calcite grains, characteristically birefractive, and dark, semitranslucent grains in the form of microcrystalline calcite highly stained by iron hydroxides (bogatić), as well as crystalline calcite with radially developed carbonate aragonite (lukovska banja) and rod-like and filamentous aggregates of aragonite and calcite, highly translucent in places (vranjska banja).the texture of the samples exhibits alternating horizontal or wavy carbonate laminae. in vranjska banja, they include thin micritic to medium crystalline laminae and laminae composed of aggregates of aragonite needles in the form of bunch. in bogatić and lukovska banja, there are thick micritic and highly porous laminae, 0.025 to 1 mm thick, or interlayers of a coarser crystalline structure. apart from encrustations, all the occurrences exhibit phototrophic microbial mats, which were analyzed by scanning electron microscopy. the onset and progress of encrustation are primarily influenced by the physical and chemical composition of the mineral water (t, ph, tds, hco3 -, ca2+, co2, etc.), as corroborated by hydrogeochemical modeling software phreeqc 3.4.0. in addition, phototrophic biofilms might be contributing to the creation and accumulation of minerals in the encrustations. saturation of the solution and the formation of encrustations (papić, 1999; houben, 2000; houben, 2001; garcia et al., 2005; de zwart, 2007; dragišić & polomčić, 2009). encrustation of the technical components of wells is non-uniform (houben, 2006), with more intensive precipitation on smooth than rough surfaces (driscoll, 1986; houben & treskatis, 2007). the main drivers of encrustation formation (papić, 1999; van beek, 2011): (i) dissolution, creating suspended substances, (ii) transport of dissolved substances, and (iii) precipitation of dissolved substances. the hydrodynamic parameters of mineral water, which faci­ li tate encrustation, include changes from laminar to turbulent flow and discharge via an overflow or groove (papić, 1999; houben & treskatis, 2007). article history: manuscript received october 26, 2018 revised manuscript accepted february 15, 2019 available online june 4, 2019 keywords: mineral water, encrustations, phototrophic microbial mats, macroscopic and optical assessment, sem analyses, x-ray powder diffraction, hydrogeochemical modeling g eo lo gi a c ro at ic a geologia croatica 72/2146 encrustations often comprise chemical compounds of cal­ cium, silicon, manganese, iron and phosphorus (houben, 2000; houben, 2001; houben & treskatis, 2007; woyessa, 2012). calcium carbonate encrustations are the most frequent type encountered in mineral water extraction (brown, 2013). protić (1995) reported similar findings, pointing out that cal­ cium carbonate encrustations in the form of calcite veins, traver­ tine, and calcite interactions in the soil and sedimentary rocks are often found in places of emergence of mineral waters in serbia, corroborated by examples of select mineral water occurrences in serbia where calcium carbonate encrustations have been de­ tected. figure 1. schematic representation of the studied mineral water sites on the hydrogeological map of serbia, including geologic columns (filipović et al., 2005; modified). geological legend: 1 – medium-grain gravel, gravelly clays, sand, sandstones, conglomerates, debris, tuffs, marls and neogene limestones; 2 – tertiary limestones; 3 – compact and fractured granodiorites; 4 – sandstones and marls, alternating marls, marly limestones and sandstones; 5 – sandstones, limestones and marls; 6 – carbonate rocks with chert, pyrite and quartz; 7 – limestones, limestones with quartz; 8 – diabases and spilites; 9 – carbonate rocks with chert and pyrite; 10 – serpentinites; 11 – hydrothermally altered rocks; 12 – heterogeneous agglomeratic material; 13 – agglomeratic, unconsolidated material; 14 – peridotbreccias; 15 – chloritic rocks; 16 – marls, occasional limestones; 17 – schistose metamorphic rocks; 18 – muscovite-biotite gneisses; 19 – silicate-amphibole schists, with quartzite interbeds; 20 – fault. hydrogeological legend: hydrogeological provinces: i – pannonian plain; ii – inner dinarides of western serbia; iii – šumadija-kopaonik-kosovo province; iv – serbian crystalline core; v – carpathian-balkanide province; vi – dacian basin; 1 – intergranular porosity (high conductivity); 2 – intergranular porosity (medium conductivity); 3 – intergranular porosity (low conductivity); 4 – hydrogeologic complex: subartesian and artesian aquifers of the neogene pannonian basin; 5 – hydrogeologic complex: subartesian and artesian aquifers of smaller neogene basins; 6 – karst and karst-fractured porosity of high conductivity; 7 – fractured porosity of low and medium conductivity (including parts of the terrain conditionally devoid of water); 8 – occurences of mineral water; 9 – hydrogeological boundary. g eologia c roatica šaraba et al.: macroscopic, optical and diffraction assessment of encrustations and sem analyses of phototrophic microbial mats ... 147 the main feature of calcium carbonate is that in the presence of carbon dioxide it becomes a readily soluble compound. the solubility of calcium hydrogencarbonate is about 160 g/l. in the absence of carbon dioxide, the solubility of calcium carbonate decreases to only about 13 mg/l. in addition, calcium carbonate exhibits retrograde solubility – as the temperature increases, the solubility decreases and vice-versa (plummer & busen­ berg, 1982; ogino et al., 1987; apello & postma, 2004). encrustations are almost always accompanied by various microbial processes (buik & wiilemsen, 2006; deed & preene, 2015), represented by prototrophic biofilms in the se­ lected occurrences of mineral water in serbia. this was the main reason why they were analyzed. microbial activity in phototrophic mats can intensify encrus­ tation, in which case the initial stage is small­scale encrustation, dominated by the biological component. over time, minerals take over and become most of the encrusted mass (schnieders, 2003; šaraba et al., 2017). phototrophic biofilms are considered to be the the earliest communities on planet earth (tice & lowe, 2006; noffke et al., 2006). the life of microorganisms in phototrophic biofilms is limited by numerous ecological factors. light is the basic fac­ tor for their growth (jemcev & đukić, 2000), but also, among others, ph value, ionic activity and temperature are unavoidable (donlan, 2002; li & logan, 2004). in most cases, micro­ organisms survive as long as they have sufficient resources for development and reproduction (lawrence & caldwell, 1987; szewzyk & schink, 1988; šaraba et al., 2017). the study of encrustations at the selected mineral water oc­ currences in serbia began with analysis of mineral deposits on the wellhead of well bb-1 at bogatić, where the scale of encrus­ tation was such that the discharge capacity of the well decreased from 60 l/s, measured in 1986 when the well was installed, to only 37.5 l/s, determined by pumping tests in 2014. conse­ quently, the well needed to be rehabilitated. the study was then extended to include a number of other wells. the objective was to detect and analyze encrustations and show that well bb-1 at bogatić was not a solitary serbian case. additional sites included lukovska banja and vranjska banja which, like the mineral wa­ ter occurrence at bogatić, featured extremely high temperatures (above 60°c) and hco3 ­ – na+ + k+ as the basic ionic composi­ tion, along with some so4 2at vranjska banja. apart from en­ crustations, phototrophic biofilms were detected in all the occur­ rences. to date, encrustations of wellheads and zones of emergence of mineral water have not been the object of hydrogeological re­ search in serbia. the study focused on determining the mineral composition of encrustations by microscopic and optical assess­ ment and x-ray powder diffraction. another objective was to es­ tablish a correlation between the chemical composition of the mineral waters and the mineral composition of the encrustations through hydrogeochemical modeling, and to assess the propen­ sity for encrustation by prognostic analyses. 2. study areas the studied occurrences are characterized by different structuralgeologic, historic­geologic, petrographic­mineralogic, hydrogeo­ logical and other properties. they are located in the hydrogeo­ logical provinces of the inner dinarides of western serbia (the occurrence in bogatić: well bb-1), the šumadija-kopaonikkosovo zone (the occurrence in lukovska banja: wells lb-4 and lb-5), and the serbian crystalline core (the occurrence in vran­ jska banja: wells vg-2 and vg-3) (fig. 1). the hydrogeological provinces of serbia have been deline­ ated based on tectonic, lithofacies, geomorphological, hydrogeo­ logical, physico-geographic and other characteristics. they coin­ cide with geotectonic units, albeit with differing boundaries, to greater or lesser extents (filipović et al., 2005; krunić, 2012) (fig. 1). the characteristics of the studied mineral waters are shown in table 1. 3. materials and methods investigations that focused on the encrustation of wellheads and selected zones of occurrence of mineral water were conducted from 2014 to 2017 in serbia, at bogatić (well bb-1), lukovska banja (wells lb-4 and lb-5) and vranjska banja (wells vg-2 and vg-3). sem analyses of phototrophic biofilms were also performed. consistent with the set requirements and objectives of the study, the materials used and methods applied corresponded to the scope and sequence of the investigations as shown in figure 2. 3.1. sampling of mineral waters samples of mineral water for physical and chemical analyses were collected in plastic bottles. the bottles were sterile and the caps complied with international standards iso 9001, iso 14001 and ohsas 18001. prior to use, the bottles were rinsed and cleaned with a 1% hcl solution, then flushed with distilled water. upon sampling of mineral water, the bottles were capped to pre­ vent leakage and then sealed with a nut. the bottles were labeled, indicating serial numbers and other important information, in­ table 1. characteristics of the studied mineral water wells (milivojević, 1989; martinović & milivojević, 1998; krunić, 1999; filipović, 2003; filipović et al., 2005; krunić, 2012; martinović, 2012). locality well designation type of well depth of well (m) function lithology type of aquifer and hydrodynamic characteristic yield (l/s) bogatić bb-1 drilled 470 heating of residential buildings and hot houses triassic limestone karst, confined 37.5 lukovska banja lb-4 401 health-and-recreation, heating of buildings; cretaceous limestone karst-fractured, confined 4.7 lb-5 870 health-and-recreation, heating of buildings; cretaceous limestone karst-fractured, confined 4.6 vranjska banja vg-2 1064 health-and-recreation, heating of buildings; petrified granodiorite and gneiss -granite, amphibole-biotite schist fractured, confined 26 vg-3 1470 health-and-recreation, heating of buildings; petrified quartz-diorite, grandiorite, with schist intercalations fractured, confined 21 g eo lo gi a c ro at ic a geologia croatica 72/2148 cluding the name of the sampling site, water temperature (t), ph and conductivity (ec). 3.2. sampling of encrustations well ageing and the sampling points within the studied zones of emergence of mineral water are illustrated in figure 3. encrusta­ tions (fig. 3) were sampled at bogatić (the well bb-1), lukovska banja (wells lb-4 and lb-5) and vranjska banja (wells vg-2 and vg-3), and labeled after wells: bb-1, vg-2, vg-2* and vg3. sample vg-2* was part of the sample vg-2. samples from wells lb-4 and lb-5 at lukovska banja were pulverized at the same time for the x-ray powder diffraction assay and labeled lb. hence, a total of five samples were tested (fig. 4). 3.3. sampling of phototrophic microbial mats mat samples were collected near the points of emergence of mine ral water and at wellheads in bogatić, lukovska banja and vranj ska banja (fig. 3). sampling sites with notable highly-de­ veloped and variously coloured biofilm were chosen for analysis by scanning electron microscopy. the samples were collected using a sterilized scalpel, placed in sterile plastic bottles and fixed with a 1.5% formaldehyde solution. 3.4. physical and chemical analyses of mineral waters the mineral water samples were delivered to the laboratory at the public health institute of belgrade, within the prescribed time­ frame, for all the required physical and chemical analyses (tab. 2). the temperature (t), ph and conductivity (ec) of the mineral waters were determined in situ. cyberscan con 510 ph me­ ter was used to determine ph levels and temperatures. this in­ strument could also be used to measure total dissolved solids (tds). conductometer hi98192 was used to measure conductivity. this instrument is equipped with a four-ring hi763133 con­ ductivity electrode. figure 2. algorithm of the applied methodology. g eologia c roatica šaraba et al.: macroscopic, optical and diffraction assessment of encrustations and sem analyses of phototrophic microbial mats ... 149 the colour of the mineral water samples was determined colorimetrically (pt-co scale), gravimetry was used to determine tds and volumetry to test the kmno4 demand. with regard to macrocomponents, na+, k+,ca2+, mg2+ were determined by aas (atomic adsorption spectrometry), hco3 ­, cl­ by the volumetric method, and so4 2by the turbidimetric method. the concentra­ tions of nh4 +, no3 ­ and no2 ­ were established by means of uvvis spectrophotometry, and silica concentrations by icpoes spectrometry. the concentrations of metals and metalloids (pb total, al total, fe3+, ni total, ag total, cd total, hg total, as total, zn total) were determined by aas. gas analyses were performed to determine the concentrations of free co2, free h2s and dis­ solved o2. the volumetric method was used for dissolved o2 and free co2, while h2s was determined by aas. 3.5. petrographic-mineralogic testing of the encrustations petrographic­mineralogic testing was undertaken at the labora­ tory of the university of belgrade/faculty of mining and geology, to define the structural and textural properties of the encrus­ tations, by means of macroscopic, optical and diffraction techniques. 3.5.1. macroscopic assessment of the encrustations the samples were tested with diluted hydrochloric acid (hcl) in a glass, by adding 10 ml of the acid. the samples were observed by the naked eye and through a 20x magnifying glass. 3.5.2. optical assessment of the encrustations three thin sections of the encrustations were prepared and viewed on a polarization microscope. a complex configuration of several software­interfaced devices was used, which included a leica polarization microscope (model dmlsp) and leica dig­ ital camera (model dc300). 3.5.3. x-ray powder diffraction of the encrustations the encrustation samples (fig. 4) were analyzed on an automatic powder diffractometer, rigaku smart lab, under the following conditions: radiation from a copper anticathode – wavelength figure 3. condition of wells and points of sampling of phototrophic microbial mats and encrustations in the studied zones of occurrence of mineral water (photo: m. lazić, 2014-2017; v. šaraba, 2017). legend: a, b. bogatić; c, d. lukovska banja; e, f. vranjska banja. g eo lo gi a c ro at ic a geologia croatica 72/2150 cukα = 1.54178 å, tube voltage u = 40 kv, and current i = 30 ma. the samples were analyzed in the 3 – 70º 2q range, with a 0.01º degree step and a data acquisition rate of 5.0º/min. the re­ sulting diffraction maxima 2q(º) and corresponding intensities (i) of each identified mineral were graphically represented. the crystalline phases (minerals) were identified based on intensities (i/imax) and interplanar spacing (di), which were compared with data from the literature and icdd pdf-2 (2016) standards. 3.6. hydrogeochemical modeling hydrogeochemical modeling, using phreeqc 3.4.0. (u.s. geo­ logical survey) and database phreeqc.dat (parkhurst & ap­ pelo, 1999), and the results of chemical analyses of five mineral water samples, was undertaken to determine the saturation index (si) of the primary minerals from the carbonate group (calcite, dolomite, aragonite), the oxide and hydroxide group (gibbsite, goethite, haematite), and the silicate group (quartz, clay mine rals, micas, etc.). 3.7. prognostic analyses prognostic analyses included mathematical calculations of the langelier saturation index (silang) and ryznar stability index (siryz), based on the chemical parameters of the mineral waters, which were used to approximate the propensity of the mineral waters for encrustation. 3.8. sem analyses of phototrophic microbial mats phototrophic microbial mats and microorganisms were analyzed in detail using a jeol jsm-6610lv scanning electron micro­ scope in the laboratory of the faculty of mining and geology at the university of belgrade. the samples were coated with gold using a baltecscd-005 sputter coating device and re­ corded under high vacuum conditions, after which a high­reso­ lution scanning electron image was obtained. 4. results and discussion the chemical composition of mineral water is a key driver of the onset and progress of encrustation, given that the process is pri­ marily steered by dissolved salts. the results of physical and chemical analyses showed that the mineral waters at bogatić and lukovska banja are of the hco3 ­-na++k+ type, and at vranjska banja of the so4 2-, hco3 ­ -na++k+ type. elevated concentrations of hco3 ­ and ca2+ ions are a mine­ ral water parameter that causes carbonate precipitation (woy­ essa, 2012), as was found to be the case with the studied mineral water occurrences, at least with respect to the hco3 ­ ion (hco3 ­ : bb-1 – 361.6 mg/l; lb-4: 961.0 mg/l; lb-5: 961.0 mg/l; vg-2: 589.0 mg/l; vg-3: 598.0 mg/l) (tab. 2), given that the proportion of the ca2+ ion is smaller than of na+ + k+ (ca2+ : bb-1 – 33.5 mg/l; lb-4 – 41.6 mg/l; lb-5 – 83.2 mg/l; vg-2 – 12.8 mg/l; vg-3 – 16.0 mg/l) (tab. 2). waters with a ph of 7.5 and above and a hco3 ­ concentra­ tion of 120 mg/l and above are more likely to precipitate carbonates and form encrustations, if such waters also contain the ca2+ ion (schwankl et al., 2008), as in the case of the studied mineral waters. the chemical composition of mineral waters is a result of the geologic framework. the geologic columns at bogatić and lu­ kovska banja include limestones, whereas those at vranjska banja comprise rocks of igneous/metamorphic origin (fig. 1). the geologic framework has an indirect effect on encrustation. according to majkić (2013), carbonate encrustations can be formed not only in limestone environments, but also at wells that tap mineral waters from other lithologic settings, with carbonate concentrations greater than several mass percent, as in the case of the wells at vranjska banja, where all the occurrences exhib­ ited encrustations of carbonate origin. van beek et al. (2010), report similar findings, pointing out the dominant presence of carbonate encrustations in limestone environments. encrusta­ tions of various origins, including carbonate, can be found in metamorphic settings and those with intercalations of igneous rocks. all the tested occurrences belong to the group of hot mineral waters, with a temperature range of 62 – 93.9°c and a ph range of 6.6 – 8.0: mildly acidic (well lb-5) to mildly alkaline (wells bb-1, lb-4, vg-2 and vg-3) mineral waters. according to jones & renaut (2010), high temperatures and elevated ph of mineral waters are conducive to, inter alia, carbonate encrus­ tation. woyessa (2012) and demir et al. (2014) also point out that carbonate encrustations on mineral water wells, especially where mineral waters are hot (>60°c). richards (2016) dis­ cusses the importance of temperature from the carbonate encrus­ tations perspective and shows that waters of moderate hardness and alkalinity tend to be devoid of carbonate encrustations at figure 4. samples of encrustations: a. bogatić (sample bb-1); b. lukovska banja (sample lb); and c. vranjska banja (samples vg-2, vg-2* and vg-3) (photo: o. krunić & v. šaraba, 2017). g eologia c roatica šaraba et al.: macroscopic, optical and diffraction assessment of encrustations and sem analyses of phototrophic microbial mats ... 151 lower temperatures. a temperature increase leads to encrusta­ tion, if all other conditions remain constant. the following types of encrustations are mostly observed in mineral waters with elevated temperature: (i) carbonates, such as calcium and strontium carbonates, (ii) silicates, (iii) heavy metal sulfides, and (iv) various types of chloride compounds (ju­ ránek et al., 1987; arnórsson, 1989; gill, 1998; po­ tapov et al., 2001; gallup, 2002; demir et al., 2014). in ad­ dition, waters of high temperature are saturated with silicon dioxide and nearly saturated with calcite, calcium sulfate, calcium fluoride, magnesium silicates, aluminum, iron, and metal sulfides (ölçenoğlu, 1986; gunnlaugsson & einarsson, 1989; kristmannsdóttir, 1989; honegger et al., 1989; pátzay et al., 2003; demir et al., 2014). woyessa (2012) reports data on carbonate encrustation from mineral waters with ph levels lower than 8.3, which is the case in the present study (ph: bb-1– 6.9; lb-4 – 7.5; lb-5 – 6.6; vg-2 – 7.9; vg-3 – 8.0) (tab. 2), and appelo & postma (2004) state that carbonate encrustations are dominant at ph˂8.3. conductivity, a property of mineral water determined in situ, which depends on the concentration of dissolved salts, measured higher values in lukovska banja and vranjska banja (wells: lb-4 – 1513 μs/cm; lb-5 – 1588 μs/cm; vg-2 – 1584 μs/cm; vg-3 1707 μs/cm). this was an indicator of a higher tds level com­ pared to the mineral water at bogatić (well bb-1 800 μs/cm). following accurate determination of tds, the occurrences in lukovska banja and vranjska banja were classified as mineral waters where total dissolved salts were greater than 1 g/l (wells: lb-4 – 1267 mg/l; lb-5 – 1058 mg/l; vg-2 – 1213 mg/l; vg-3 1145 mg/l). the occurrence at bogatić belongs to the group of mineral waters with concentrations of dissolved salts less than 1 g/l (well bb-1 600 mg/l) (tab. 2). tds directly affects encrustation; the higher the tds level, the more probable the creation of encrustations (papić, 1999). gas analyses included carbon dioxide (co2), oxygen (o2) and hydrogen sulfide (h2s). the concentration of co2 was sig­ nificant from a carbonate encrustations perspective. according to houben (2001) and deed & preene (2015), carbonate encrustations, contrary to iron encrustations, occur when the par­ tial pressure of co2 is lower than the atmospheric pressure, es­ pecially under high water temperature conditions as in the study cases. co2 is released from the water and disturbs the carbonate equilibrium of the solution, leading to carbonate encrustation. table 2. results of physical and chemical analyses of the studied occurrences of mineral water (šaraba et al., 2017). parameter bogatić lukovska banja vranjska banja bb-1 lb-4 lb-5 vg-2 vg-3 t (°c) 65.9 68.1 62.0 93.9 91.2 tds (mg/l) 600 1267 1058 1213 1145 ph 6.9 7.5 6.6 7.9 8.0 t (ntu) / / 14.9 0.6 0.8 kmno4 demand (mg/l) 6.9 2.2 3.2 5.5 4.2 color (pt-co scale) / / 25 <5 <5 ec (µs/cm) 800 1513 1588 1584 1707 macrocomponents (mg/l) na+ 144.0 309.6 166 358.0 346.4 k+ 13.0 23.6 18.6 19.4 18.4 ca2+ 33.5 41.6 83.2 12.8 16.0 mg2+ 6.6 17.1 32 <1.0 <1.0 hco3 361.6 961.0 961.0 589.0 598.0 so4 27.5 91.3 50.3 548.7 487.0 cl103.4 82.0 46.0 64.0 60.0 microcomponents (mg/l) pb <0.003 / 0.04 <0.01 <0.01 fe3+ 0.17 0.23 0.07 0.20 <0.10 al <0.04 <0.04 <0.04 5.04 5.04 ni / / 0.11 <0.01 <0.01 ag / / <0.013 / / cd / / / <0.02 <0.02 hg / / / <0.001 <0.001 as 0.002 / 0.689 <0.01 <0.01 zn 0.002 / <0.014 <0.02 <0.02 no3 0.3 0.7 0.5 2.3 5.3 no2 0.002 0.005 <0.005 <0.02 <0.02 nh4 + 1.80 1.05 0.75 0.31 0.32 sio2 64 50 50 90 90 gases (mg/l) free co2 50.5 140.0 150.0 184.6 194.2 dissolved o2 0.5 / / 4.5 3.7 free h2s 2.5 / <0.06 0.008 0.006 legend: forward slash (/) = not analyzed. g eo lo gi a c ro at ic a geologia croatica 72/2152 co2 release from the water increases the ph level, which contributes to carbonate precipitation (appelo & postma, 2004). in addition, gas solubility decreases with increasing water temperature, which leads to the release of co2. the solubility of carbonates in water depends on the amount of dissolved co2. as this amount decreases, so does the solubility of carbonate mine­ rals, resulting in a higher rate of carbonate encrustation of the well. this reaction is rapid, such that carbonate encrustations are formed almost instantly (appelo & postma, 2004; houben & treskatis, 2007; brown, 2013). in such a setting, carbonate encrustation can be expressed by a reverse reaction (1), where there is an equilibrium between calcium hydrogencarbonates, calcium and hydrogencarbonate ions, solid calcium carbonate, and carbon dioxide in the mineral water solution (appelo & postma, 2004): ca (hco3)2 ↔ ca2+ + 2hco3 – ↔ caco3↓ + co2 + h2o, (1) the highest concentrations of this gas were recorded at vranjska banja (well vg-2 – 184.6 mg/l free co2; well vg-3 – 194.2 mg/l free co2) and lukovska banja (welllb-4 – 140.0 mg/l free co2; welllb-5 – 150.0 mg/l free co2). those at bogatić were lower (well bb-1 – 50.5 mg/l free co2) (tab. 2). the chemical compositions of the examined occurrences were illustrated in hydrochemical diagrams, which clearly indi­ cate the hydrochemical types of mineral water at each location. figure 5 shows the basic ionic compositions, which are in­ directly indicative of the tds levels. it is apparent that the hco3 ­ and na+ + k+ ions were dominant in the mineral waters at bogatić and lukovska banja, while at vranjska banja there were also elevated concentrations of the so4 2ion. figure 5 also shows that at bogatić the highest proportion is of the hco3 ­ion, followed by the cl­ ion. the waters at lukovska banja and vranjska banja measured the lowest cl­ ion concentrations. with regard to all the mineral water occurrences, the decreasing order was na+ + k+, ca2+ and mg2+. it is apparent that the mineral water from bogatić measured the lowest concentration of dissolved salts and that tds was less than 1 g/l, compared to the other occurrences where tds was greater than 1 g/l. figure 6 is a hydrochemical cl– – so4 2– – hco3 – ternary graph, which shows that all the tested mineral water samples were in the high bicarbonate ion concentration range and that the mine­ ral waters could be classified as peripheral waters that may have mixed with cold groundwater. the mineral water at well bb-1 (bogatić) was near the cl­ range but still in the hco3 ­ range, which is indicative of cl­ being the second prevalent ion, after bicarbonate. the position on the graph also suggests very low concentrations of the so4 2ion. closely positioned mineral wa­ ters from wells lb-4 and lb-5 (lukovska banja), and wells vg-2 and vg-3 (vranjska banja), are a result of the same geologic set­ ting from which the mineral waters are extracted. this has led to similar concentrations of the hco3 ­, so4 2and cl­ anions. in the case of the mineral waters from wells lb-4 and lb-5 (lukovska figure 5. diagram of radial coordinates of the tested mineral waters. legend: bb-1 – well in bogatić; lb-4, lb-5 – wells in lukovska banja; vg-2, vg-3 – wells in vranjska banja. g eologia c roatica šaraba et al.: macroscopic, optical and diffraction assessment of encrustations and sem analyses of phototrophic microbial mats ... 153 banja), the points are close to the corner of hco3 ­, such that these waters have high bicarbonate concentrations. the mineral waters from wells vg-2 and vg-3 are near the steam heated waters, but still in the peripheral range. in such cases bicarbonate and sulfate ions are predominant. according to dolgorjav (2009), closely positioned mineral waters on the cl­ – so4 2– hco3 ­ graph (fig. 6), such as those from wells vg-2 and vg-3 (vranjska banja), originate from high­temperature systems and can be associated with deep geo­ logic structures. encrustation samples (fig. 4) were tested by various methods, in order to conduct a detailed analysis. macroscopic assessment of the samples (fig. 4) revealed their colour, structure and texture: grain size, type and shape; lamination; and traces of damage/abrasion. optical assessment and the increased contrast offered by this type of microscopy, provided a sample image with a high level of sensitivity for quan­ titative and qualitative determinations (fig. 4). the x-ray powder diffraction technique was used to determine the phase composi­ tion of the samples (fig. 4), or, in other words, to conduct quali­ tative analyses. the advantage compared to other methods is that it is possible to determine which mineral is present in the samples even where the total chemical composition has been determined. macroscopic tests of all samples (wells bb-1, lb-4, lb-5, vg-2, vg-3) with diluted hydrochloric acid (hcl) resulted in strong reactions, which indicated a significant presence of calcite (caco3). the colour of the post-test solutions was dark, a poten­ tial indicator of iron oxides and hydroxides in the samples. gunnlaugsson et al. (2014) report data on encrustations of carbonate origin (calcite and aragonite) in hot mineral water wells, which are exceptionally white in color and devoid of im­ purities. this was not the case in the present study. the carbonate encrustations, along with iron and manganese oxides and hydroxides, were of the standard type found in and around wells, as corroborated by the examples of select occur­ rences of mineral waters, where as carbonate encrustations in combination with sulfates, sulfides and aluminum hydroxides are much less frequent (houben, 2000; houben, 2001). macroscopic assessment of the samples from wells bb-1 (bogatić), lb-4 and lb-5 (lukovska banja) revealed a micro/ coarse crystalline structure and a relatively well­preserved texture. multiphasic development was noted, which lent a certain laminarity to the samples. the colours of the laminae varied, from brown/ochre at well bb-1 (bogatić) to light brown, dark brown or dark gray at wells lb-4 and lb-5 (lukovska banja). the samples also exhibited thin and irregular lamination. structurally, there were thick micritic and highly porous laminae or coarse crystalline interlayers. the two alternating types of laminae could be a result of cal­ cite precipitation from warm and cold water, and the growth of cyanobacteria driven by seasonal changes (tišljar, 2001). pedley (1992), perry (1999) and riding (2000) point out frequent examples of the influence of phototrophic microbial mats on the formation of sediment textures, such as laminations and stromatolites. the samples were relatively hard and could not be crushed between fingers when dry. optical assessment corroborated a distinct laminar texture of the samples from wells bb-1 (bogatić), lb-4 and lb-5 (lukovska banja), where the laminae were very thin, from 0.025 to 1 mm. their colour differed. all the laminae, regardless of thickness, ware more or less wavy, at times leading to a deformed texture – microconvolutions. optical assessment of the sample from well bb-1 (bogatić) led to the conclusion that the predominant component was calcite. it was present in crystalline grains of various sizes – from mi­ crons (greater than 10 microns) to parts of a millimetre. the sizes of the largest monocrystals or monocrystal aggregates were up to 0.5 mm. the crystalline calcite grains were clear and birefrac­ tive. such calcite was associated with light, predominantly calcite laminae (fig. 7a). de zwart (2007) reports similar calcite crystal sizes in car­ bonate encrustations around wells, indicative of irregular calcite crystal shapes in the size range of 3–5 μm. dark, semi-transparent grains were the second largest con­ stituent of samples from well bb-1 (bogatić). these grains were aggregates of microcrystalline calcite, heavily stained by iron hydroxides (probably amorphous). they originated from thin, dark brown laminae (fig. 7a). the non-carbonate part of a sample from well bb-1 (bogatić) was a terrigenous component of pelitic size (clay minerals), inti­ mately mixed with microcrystalline calcite, including a very small quantity of quartz grains and phyllosilicate flakes (sericite/ fine flaky muscovite) of silt size. organic matter was finely dis­ persed in the sample. according to optical indicators, its concen­ tration was less than 2%. the sample from well bb-1 (bogatić) was identified as a wavy laminated calcite deposit. x-ray powder diffraction on a sample from well bb-1 (bogatić) corroborated that the primary constituent was calcite, accompanied by a much smaller quantity of quartz (fig. 8a). optical assessment of samples from wells lb-4 and lb-5 (lukovska banja) led to the conclusion that the predominant con­ stituent was crystalline calcite. there were also aggregates of microcrystalline calcite, intimately mixed with iron hydroxides. the sample contained distinct grains with radially developed car­ bonate (fig. 7b). this carbonate – aragonite generally crystallizes in high-temperature waters. at lukovska banja (wells lb-4 and lb-5), measured water temperatures ranged from 62°c to 68°c (tab. 2). in addition, aragonite aggregate needles can host microor­ ganisms which, inter alia, cause aragonite precipitation (guo & riding, 1992). as already mentioned, microbial growth in pho­ totrophic mats was noted in the studied occurrences. plummer et al. (1978), buhmann & dreybrodt (1987), chafetz figure 6. ternary clso4 2– hco3 graph of the tested mineral waters. g eo lo gi a c ro at ic a geologia croatica 72/2154 (1994) and flügel (2004) state that carbonates are the most frequent types of encrustations and those microorganisms are mediators of their creation, while flügel (2013) claims that carbonates are very often formed by freshwater microorganisms. the studied occurrences of mineral water belong to this category. samples from wells lb-4 and lb-5 (lukovska banja) also included terrigenous components (fine-grained sand fraction), but their concentrations were low. it is possible that fine quartz grains were a result of contamination during sampling or that they be­ came attached during carbonate incrustation. based on optical indicators, samples from wells lb-4 and lb-5 (lukovska banja) were identified as a laminar calcite deposit. the predominant calcite mineral in samples from wells lb-4 and lb-5 (lukovska banja) was corroborated by x-ray powder diffraction. aragonite was next, but its concentration was much lower (fig. 8b). macroscopic assessment of samples vg-2, vg-2*and vg-3 from wells vg-2 and vg-3 (vranjska banja) led to the conclu­ sion that their texture was disturbed during sampling. the sam­ ples were loose, comprised of particles, grains and fragments of sub-millimetre to centimetre size. the coarse, centimetre frag­ ments were in shades of light gray and light brown. based on sample vg-2* from well vg-2 (vranjska banja), it was assumed that the texture of the other two samples (vg-2 and vg-3) from wells vg-2 and vg-3 (vranjska banja) was the same. they ex­ hibited irregular lamination, with thin micritic to semi­crystal­ line laminae and laminae comprised of aggregates of clustered aragonite needles (fig. 7c). figure 7. microscopic view of the samples collected from: a. well bb-1 (bogatić), b. wells lb-4 and lb-5 (lukovska banja), c. well vg-2 (vranjska banja). legend: a. fine crystalline calcite base. dark lamellae comprised of grains, aggregates of micritic calcite stained by fe hydroxides; b. fine crystalline calcite base. dark grains/lamellae are micritic calcite stained by fe hydroxides; c. fine crystalline calcite base, interspersed with aragonite filaments. darker grains are aggregates of calcite and aragonite stained by fe hydroxides. figure 8. results of x-ray powder diffraction of the samples: a. bb-1 from well bb-1 (bogatić); b. lb from wells lb-4 and lb-5 (lukovska banja). g eologia c roatica šaraba et al.: macroscopic, optical and diffraction assessment of encrustations and sem analyses of phototrophic microbial mats ... 155 sample vg-2 from well vg-2 (vranjska banja) was tested by optical microscopy and samples vg-2, vg-2* and vg-3 from wells vg-2 and vg-3 (vranjska banja) were analyzed in detail by x-ray powder diffraction. optical assessment of sample vg-2 from well vg-2 (vranjska banja) led to the conclusion that the sample comprised calcite and aragonite aggregate rods and filaments. breakage of the fila­ ments was not readily visible. the structure was micro to coarse crystalline. the coarse calcite monocrystals were highly translucent. the other parts of the sample were difficult to determine optically but they included clay minerals and fe oxides and hydroxides, which had stained the sample in shades of brown (fig. 7c). based on optical indicators, sample vg-2 from well vg-2 (vranjska banja) was identified as a calcite-aragonite deposit. x-ray powder diffraction revealed that in sample vg-2 from well vg-2 (vranjska banja) the prevalent mineral was calcite, fol­ lowed by aragonite. there were no other mineral phases (fig. 9a). sample vg-2* from well vg-2 (vranjska banja) contained only calcite (fig. 9b). the primary constituent of sample vg-3 from well vg-3 (vranjska banja) was quartz, followed by calcite and a mineral from the mica group (muscovite). minerals from the pla­ gioclase and chlorite groups were less represented (fig. 9c). the results of petrographic­mineralic testing showed that the mineral and chemical compositions of the encrustations were practically the same. their common features included the pre­ dominance of calcium carbonate, a thickness of only several cen­ timetres, and a high porosity of the samples.the texture was chara cterized by alternating horizontal or wavy carbonate lami­ nae, comprised of micrites in shades of brown, stained by iron figure 9. results of x-ray powder diffraction of the samples: a. vg-2 from well vg-2 (vranjska banja); b. vg-2* from well vg-2 (vranjska banja); c. vg-3 from well vg-3 (vranjska banja). g eo lo gi a c ro at ic a geologia croatica 72/2156 oxides and hydroxides or organic substances, and those comprised of radial or medium-to-coarse crystalline calcite and aragonite. de zwart (2007) describes encrustations around wells and points out the carbonate composition and iron oxides in the min­ eral matrix, along with organic components originating from the aquifer. sedimentation is governed by changes in hydrochemical and flow conditions, with other potential additional factors. apart from calcite, the precipitation of minerals such as chlo­ rite, mica, etc. is also possible (de zwart, 2007). this is true of the mineral water in vranjska banja, where quartz, albite, mus­ covite and clinochlore were detected. demir et al. (2014) also provide data on carbonate encrus­ tations in hot mineral water wells and on water pipes, represented by calcite and aragonite, along with lead sulfide. given that aragonite is not thermodynamically stable under ambient conditions, but stable at elevated temperatures and pressures, there was a gradual transition from calcite to aragonite at increasing depths in the well, as the temperature and pressure gradually increased with depth (demir et al., 2014). mitić et al. (2014) report com­ parable findings, indicative of the carbonate composition of en­ crustations in hco3 ­ – na+ + k+ mineral waters, at a temperature of 75°c, primarily composed of aragonite, along with calcite and vaterite, as well as small amounts of anhydrite, in a 1232 m-deep well. similar temperatures characterized the selected occur­ rences of mineral waters in serbia, as well as an identical basic ionic composition. the presence of aragonite, detected in luko­ vska banja (wells lb-4 and lb-5) and vranjska banja (well vg-2), keeping in mind the reports by demir et al. (2014) and mitić et al. (2014), might be indicative of a temperature gradi­ ent in the zone of discharge and at the wellheads, as well as that calcite, dominant in the composition of the encrustations, could be a result of aragonite inversion, due to decreasing temperatures and pressures in discharge zones and on wellheads, relative to the increase in these parameters with depth. in addition, perdik­ ouri et al. (2011) claim that the creation of calcite need not be a result of aragonite inversion. such encrustations are created through precipitation from mineral waters and can be interpreted as deposition of terrestrial freshwater carbonates (calc tufa, travertine, etc.) (guo & riding, 1992; chafetz & folk, 1984; perdikouri et al., 2011). driscoll (1986) and houben & treskatis (2007) state that the main types of encrustations are chemical com­ pounds generated through the precipitation of calcium and mag­ nesium carbonates and sulfates, and iron and manganese com­ pounds – primarily hydroxides and oxides, but that there are also encrustations created by mechanical or chemical action of vari­ ous microbial species, which are the most frequently encountered encrustations in serbia (šaraba et al., 2017). carbonate encrustations favour other conditions as well, such as (schwankl et al., 2008): (i) groundwater extraction leading to changes in pressure at the point of entry into the well, which promotes carbonate encrustation, (ii) mixing of waters from different geological formations, increasing the probability of carbonate encrustation given that the studied mineral water occurrences are characterized by a complex geological frame­ work (fig. 1), (iii) evaporation of drops of mineral water, which increases the concentration of dissolved salts in the groundwater, thus contributing to precipitation. based on the mechanical characteristics of the macroscopi­ cally assessed encrustations, they can be classified keeping in mind gavrilko & alekseev (1985), who identified four types, disregarding the mineral composition of the encrustations: (i) very hard conglomeratic type, (ii) loosely stratified type, rep­ resented by cemented fine-grained material, (iii) unconsolidated porous type, characterized by high porosity of the deposited mass, and (iv) soft, pasty or jelly like deposits that contain a sig­ nificant amount of organic matter. in this regard, the encrusta­ tions from bogatić and lukovska banja belong to the first type and those from vranjska banja to the third type of encrustations. in addition, very hard carbonate encrustations are generally associated with rhombohedral calcite, whereas soft and soluble carbonate encrustations are mostly built up of orthorhombic cal­ cite and are easier to remove from different surfaces (stojiljković et al., 2015). the hydrogeochemical modeling program phreeqc 3.4.0. (u.s. geological survey) and database phreeqc.dat (parkhurst & appelo, 1999) were used to process the set of hydrochemical data, shown in table 2, and to calculate the saturation index (si) of all minerals that can hypothetically be formed from the mine­ ral water of a given chemical composition. the focus was on the primary minerals of the carbonate group (calcite, dolomite and aragonite), the oxide and hydroxide group (gibbsite, goethite and haematite), and the silicate group (quartz, clay minerals, micas, etc.), as the most probable constituents of the studied encrusta­ tions. only positive values of the saturation index (si>0) were interpreted, given that they suggested supersaturation of the water with a given mineral and, consequently, the possibility of its pre­ cipitation (appelo & postma, 1994). the results of modeling are shown in table 3. given that the presence or absence of a certain mineral in encrustations depends, inter alia, on the precipitation rate under given conditions (i.e. si>0 does not necessarily mean that the mineral is in fact present in the encrustations), the results of hy­ drogeochemical modeling of si were interpreted in accordance with those of the macroscopic and optical assessments and x­ray powder diffraction. the saturation index of the sample of mineral water from bogatić (well bb-1) was indicative of only a slight calcite super­ saturation, which suggested the possibility of small carbonate deposits through encrustation. this was corroborated by miner­ alogic analyses of the sample from that location. mild supersatu­ ration of the mineral water with quartz (si = 0.15) was insufficient to create silicate encrustations (brown, 2013). the other posi­ tive si values were associated with iron oxides and hydroxides, as well as muscovite and kaolinite, which comprised the non­ carbonate part of the examined encrustations. a comparison of the hydrogeochemical model of the mineral water sample from well bb-1 with the results of optical and x-ray assessments of the encrustations from well bb-1 revealed that all of the minerals identified in the encrustations were indeed precipitated from the mineral water, with the exception of quartz grains, which were likely a result of contamination during sampling. hydrogeochemical modeling of the mineral water samples from lukovska banja (wells lb-4 and lb-5) indicated possible precipitation of calcite and aragonite, as well as iron oxides and hydroxides. the presence of these minerals was corroborated by mineralogic and x-ray analyses of the encrustation samples. the model also suggested the possibility of precipitation of magne­ sium and potassium silicates, as well as kaolinite and dolomite, but they were not detected in the sample. quartz was virtually in a state of chemical equilibrium with water (positive si, but close to zero), so the assumption was that its presence in the encrusta­ tions was a result of contamination during sampling. g eologia c roatica šaraba et al.: macroscopic, optical and diffraction assessment of encrustations and sem analyses of phototrophic microbial mats ... 157 positive si were calculated for the following minerals from the mineral water samples from vranjska banja (wells vg-2 and vg-3): calcite and aragonite; iron oxides and hydroxides; and kaolinite. these minerals were also identified by optical assess­ ment of the encrustation samples. the hydrogeochemical model suggested the possibility of precipitation of muscovite and chlo­ rite from the water, the presence of which in the encrustations was corroborated by x-ray testing of the sample from well vg-3. however, it should be noted that the petrographic-mineralogic analysis revealed that this sample also contained part of the pa­ rent rock. mild supersaturation with dolomite and gibbsite was not confirmed. quartz was virtually in a state of equilibrium with water in this case as well (negative si, but close to zero). based on macroscopic and optical assessments of the encrus­ tations from the threelocations, the conclusion was that the en­ crustations originated from the water solution, through precipita­ tion of calcite, laminar development, and varying degrees of staining with iron hydroxides. the silicate minerals could have been attached in the development process, particularly phyllo­ silicates (sericite and clay minerals), but the possibility of con­ tamination during sampling should not be excluded. however, the positive si of the silicate minerals in the mineral water sam­ ples from all three locations tend to suggest that they were at­ tached during the precipitation of encrustations. according to mullin (2001), brezonik & arnold (2011) and richards (2016), carbonate precipitation begins with nucleation in the mineral water solution. colliding ions, ori­ ented in a certain way, initiate the creation of a crystalline struc­ ture, forming carbonate encrustations that gradually become a continuous layer. the nucleation process can be primary or sec­ ondary. primary nucleation refers to original carbonate precipi­ tates, which did not pre-exist in the solution. secondary nuclea­ tion is the growth of existing carbonate encrustations. the langelier saturation index (silang) (2) and ryznar stability index (siryz) (4) were used to test the stability of the mine ral waters at bogatić, lukovska banja and vranjska banja (tab. 4). silang = ph – phs, (2) phs = 9.92 – t 40 – log[ca2+] – log[hco3 –] + 0.2log[s.o.], (3) siryz = 2phs – ph, (4) where: silang – langelier stability index, siryz – ryznar stability index, ph – measure of hydrogen ion (h+) activity in solution, phs – ph at which the water is saturated with calcium carbonate, t – groundwater temperature (°c), ca2+ – calcium concentration (mg/l), hco3 – – bicarbonate concentration (mg/l), s.o. – dry residue (mg/l). these two indices consider water solely from the standpoint of the balance between concentrations of the following compo­ nents: carbonates and bicarbonates, on one hand, and carbonic acid on the other (deberry, 1982). table 4. langelier saturation index (silang) and ryznar stability index (siryz) (šaraba et al., 2017). well ph phs silang siryz bb-1 6.9 6.2 0.7 5.5 lb-4 7.5 6.6 0.9 5.7 lb-5 6.6 6.4 0.2 6.2 vg-2 7.9 6.2 1.7 4.5 vg-3 8.0 6.1 1.9 4.2 legend: bb-1 – well in bogatić; lb-4, lb-5 – wells in lukovska banja; vg-2, vg-3 – wells in vranjska banja. table 3. saturation indices (si) of the primary minerals from the carbonate group (calcite, dolomite and aragonite), the oxide and hydroxide group (gibbsite, goethite and haematite), and the silicate group (quartz, clay minerals, micas, etc.). locality/well mineral phase si formula bogatić (bb-1) calcite 0.08 caco3 goethite 7.03 feooh haematite 16.24 fe2o3 k-mica 3.67 kal3si3o10(oh)2 kaolinite 0.86 al2si2o5(oh)4 quartz 0.15 sio2 lukovska banja (lb-4) aragonite 0.93 caco3 calcite 1.04 caco3 chlorite(14a) 2.92 mg5al2si3o10(oh)8 chrysotile 0.05 mg3si2o5(oh)4 dolomite 2.19 camg(co3)2 goethite 7.14 feooh haematite 16.46 fe2o3 k-mica 2.09 kal3si3o10(oh)2 quartz 0.01 sio2 lukovska banja (lb-5) aragonite 0.31 caco3 calcite 0.43 caco3 dolomite 0.96 camg(co3)2 goethite 6.63 feooh haematite 15.43 fe2o3 k-mica 4.49 kal3si3o10(oh)2 kaolinite 1.54 al2si2o5(oh)4 quartz 0.09 sio2 vranjska banja (vg-2) anorthite 0.12 caal2si2o8 aragonite 0.72 caco3 ca-montmorillonite 0.00 ca0.165al2.33si3.67o10(oh)2 calcite 0.83 caco3 chlorite(14a) 5.55 mg5al2si3o10(oh)8 dolomite 0.34 camg(co3)2 gibbsite 0.30 al(oh)3 goethite 6.44 feooh haematite 15.14 fe2o3 illite 0.00 k0.6mg0.25al2.3si3.5o10(oh)2 k-mica 6.25 kal3si3o10(oh)2 kaolinite 1.61 al2si2o5(oh)4 quartz -0.02 sio2 vranjska banja (vg-3) anorthite 0.26 caal2si2o8 aragonite 0.89 caco3 ca-montmorillonite 0.06 ca0.165al2.33si3.67o10(oh)2 calcite 0.99 caco3 chlorite(14a) 6.19 mg5al2si3o10(oh)8 chrysotile 0.14 mg3si2o5(oh)4 dolomite 0.65 camg(co3)2 gibbsite 0.28 al(oh)3 goethite 5.85 feooh haematite 13.96 fe2o3 illite 0.11 k0.6mg0.25al2.3si3.5o10(oh)2 k-mica 6.29 kal3si3o10(oh)2 kaolinite 1.60 al2si2o5(oh)4 quartz 0.00 sio2 g eo lo gi a c ro at ic a geologia croatica 72/2158 silang can only be used to predict the ability of water to precipitate dissolved calcium carbonate, not calcium sulfate or calcium phosphate (majkić-dursun et al., 2016). siryz is suitable for moderately hard to hard waters, but not soft or brack­ ish waters. even though the use of these indices is widespread, they can only approximate the stability of mineral waters (de­ berry, 1982). siryz˂7 indicates precipitation of encrustations, siryz>9 that the predominant process is corrosion, and 7˂siryz˂9 that both, precipitation of encrustations and corrosion, are possible (ryznar, 1994). all of the studied occurrences of mineral wa­ ter are characterized by siryz˂7 (tab. 4), which indicates that the precipitation of encrustations is the predominant process on wellheads and within the zones of emergence. silang values greater than zero in the case of the three stu­ died mineral water occurrences (tab. 4) indicate calcium carbonate precipitation on all the wells. based on siryz values (tab. 4), the mineral waters of wells bb-1, lb-4 and lb-5 tend to precip­ itate calcium carbonate because siryz≥5.5, while siryz˂5.5 (wells vg-2 and vg-3) suggests that the mineral water at vranjska banja has an exceptional propensity for calcium carbonate precipitation. silang can also be used to determine the rate of encrusta­ tion. if silang ˂ 0.5, then the rate of encrustation is up to 0.2 g/ m2 h; if 0.5˂silang˂1, then 0.2 to 0.5 g/m2 h; and if silang>1, then it is greater than 0.5 g/m2 h (langelier, 1936; vuković & soro, 1992). according to the values of silang in tab. 3, the mineral wa­ ter from well lb-5 belongs to the first category (encrustation rate 0.2 g/m2h, silang˂0.5), the mineral water from wells bb-1 and lb-4 to the second category (rate from 0.2 to 0.5 g/m2 h, 0.5˂si­ lang˂1), and the mineral water from wells vg-2 and vg-3 to the third category (rate higher than 0.5 g/m2h, silang˂0.5). according to morozov & mershchii (1979), mineral waters characterized by siryz˂9, silang>0 and fe3+˂0.3 mg/l will likely precipitate calcium and magnesium compounds, with caco3 being predominant. all the studied occurrences measured fe3+ less than 0.3 mg/l (wells: bb-1 – 0.17 mg/l; lb-4 – 0.23 mg/l; lb-5 – 0.07 mg/l; vg-2 – 0.20 mg/l; vg-3 ˂ 0.10 mg/l) (tab. 2), and silang>0 and siryz˂9 (tab. 4), which corroborated the predominant carbonate composition of the analyzed encrus­ tations. 4.1. phototrophic microbial mats it is well known that many microorganisms, including phototro­ phic ones, can contribute to the precipitation of minerals on some surfaces. thus, the encrustations can be affected by the formation of phototrophic biofilms, which can lead to the creation and ac­ cumulation of minerals in several ways. cyanobacteria, for ex­ ample, can incorporate different particles into their sheaths, among which carbonate minerals are the most common (whit­ ton, 2012). sheaths are mostly composed of extracellular poly­ meric substances (eps), highly organized polymers that accu­ mulate outside the cell forming a matrix with multiple roles (seckbach & oren, 2010). the most common role is the pro­ tection of the microorganism’s cell from various harsh conditions. harsh conditions are mostly high or low temperatures, uv ra­ diation, changes in environmental chemistry, desiccation, preda­ tors, etc. according to many researchers, the most important role of eps is its water retention capability and protection from de­ siccation. the binding ability of eps is certainly very useful and an in­ teresting feature (whitton, 2012). eps is capable of binding different particles, but also nutrients that can be of importance for biofilm functioning. mineral precipitation often occurs within the eps, rather than on the surface of cyanobacterial sheaths (seck­ bach & oren, 2010). uronic acids play the main role in eps. these charged groups are capable of interacting with sediment particles and it is believed that they can be involved in the regula­ tion of the calcification process. extracellular layers are particu­ larly favourable sites for nucleation, and cyanobacterial species that produce sheaths or eps generally precipitate more calcium carbonate than species without sheaths (whitton, 2012). the analysis of phototrophic biofilms in this study was per­ formed using scanning electron microscopy. light microscopy in šaraba et al. (2017) provided an insight into the diversity of phototrophic microorganisms but scanning electron microscopy enabled more detailed analysis and allowed that the sample sur­ face and morphology, the shape and size of different biofilm con­ stituents, and their orientation, distribution and the way of attach­ ment to be explored. by using this technique, we wanted to highlight the samples where eps was present or dominant or where some mineral particles were visible and attached to eps. the presence of the three dominant algal divisions in the phototrophic biofilms was recorded, including chlorophyta, cyanobacteria and bacillariophyta (šaraba et al., 2017) (fig. 10), where cyanobacteria, especially non-heterocytous trichal forms, were dominant in biofilm samples from all the localities. the sem micrographsof phototrophic biofilms (figs. 10a, b, d, e below) show the developed layer of extracellular polymeric substances (eps). in general, mineral deposits attached to eps are visible in the form of small particles, but also large particles (e.g. fig. 10a). sem analysis of biofilm samples from bogatić mainly revealed the domination of trichal cyanobacteria that were densely entangled and embedded in the extracellular matrix cove­ red with different mineral particles (figs. 10c and 10d). trichal cyanobacteria were also visible in the sample from lukovska banja (fig. 10c), but representatives of bacillariophyta were also present. in this sample, eps was not as developed as in the sam­ ples from bogatić. particles of different origin were noted in eps from vranjska banja (fig. 10e), along with bacillariophyta repre­ sentatives. according to the micrographs, biofilm was highly de­ veloped and cyanobacteria abundant in samples from bogatic and lukovska banja (less abundant in vranjska banja). cyanobacteria (when phototrophic microorganisms are con­ sidered) can play an important role in the formation of encrustra­ tions. for example, according to pedley (1992), perry (1999) and riding (2000), laminar carbonate encrustations, generally wavy, in combination with phototrophic biofilm, are a result of carbonate silt and fine sediment trapped by the microbial popula­ tions. recent encrustations, such as those sampled in this re­ search, generally contained alternating organic and inorganic laminae. while the organic laminae were composed of different species of cyanobacteria, inorganic laminae comprised carbonate silt, which cyanobacteria had captured from the water. besides the capability of eps to attach different particles, the microorganisms themselves can induce mineral precipitation. phototrophic microbial matsare characterized by temporal and spatial dynamics and highly diverse metabolic pathways in the creation of minerals. during the day, photosynthesis and its or­ ganic products in the surface layer of the biofilm are the main factors of the origin of mineral precursors (metabolic fixation of inorganic carbon tends to increase the ph of the solution and lead g eologia c roatica šaraba et al.: macroscopic, optical and diffraction assessment of encrustations and sem analyses of phototrophic microbial mats ... 159 to a state of carbonate supersaturation). on the other hand, at night, during respiration, totally different micro conditions are created (lower ph, o2, higher co2, and the like), where products of respiration can dissolve minerals. in addition, the stratification of phototrophic microbial mats that is common in biofilms near thermal springs and the coexistence and cooperative metabolism of a large number of microorganisms can lead to the creation of diverse minerals in a small space, depending on the hydrochemi­ cal characteristics of the mineral water and environmental con­ ditions. due to their anoxygenic photosynthetic ability in the presence of h2s, cyanobacteria can survive in extreme environ­ ments where many algae cannot live. the product of this process, elemental sulphur, can be deposited in the form of fine granules on the filament surface, which is no longer oxidized except in the presence sulfur oxidizing bacteria. therefore, if calcium is present in high concentrations, they can facilitate the formation of various morphotypes of gypsum minerals (edinger, 1973; tang et al., 2014; kaźmierczak et al., 2015). 4.2. implications the studied occurrences of mineral water definitely deserve spe­ cial attention in the future, including the establishment of perma­ nent monitoring, which would, inter alia, track the condition of steel wellheads and zones of emergence of mineral water, which are ideal substrates for encrustation and biofouling. the life manifestations of phototrophic mats come with different well ageing symptoms and they contribute to encrustation, among other things. preemptive action indicated by monitoring would help avoid the need for well rehabilitation, which is costly. the wells would thus be maintained in a state of maximum productivity. spending would be minimized, mineral water would be used for heating and health­and­recreation purposes without interruption, and the quality of the mineral water would be sustained, with no adverse effect on its organoleptic properties. in addition, many of the identified phototrophic microorgan­ isms are able to generate medicinal and economically-significant products and can be used by the biotechnological industry as a figure 10. sem micrographs of cyanobacteria and phototrophic biofilm algae. legend: a, b. bogatić (trichal cyanobacteria embedded in eps covered with particles of different origin); c, d. lukovska banja (trichal cyanobacteria and bacillariophyta); e, f. vranjska banja (bacillariophyta representatives visible on both micrographs). g eo lo gi a c ro at ic a geologia croatica 72/2160 source of vitamins, enzymes, lactic acid and other substances of relevance to agriculture and medicine (šaraba et al., 2017). the present study shows that the examined mineral waters, regardless of their extremely high temperatures and specific physical and chemical compositions, support the development of various microbial communities and constitute a starting point for studying thermal habitats, which to the present day remain unin­ vestigated biotopes, at least in serbia. there is also the need to protect the environment and the genetic diversity of such habitats. moreover, encrustations are significant because they have a serious impact on the life cycle of a well, as it reduces the well’s capacity, threatens the integrity of its structural components (fig. 3), and changes the organoleptic properties of the mineral water, causing foul odour, unpleasant taste, turbidity etc., (houben & treskatis, 2007). the research conducted in lukovska banja and vranjska banja corroborated that the well in bogatić is not a solitary case of encrustation coupled with biofouling. a large number of wells have encrustation issues. the water industry has been aware of the problem for more than 100 years (howsam et al., 1995; de zwart, 2007; sterrett et al., 2008; deed & preene, 2015). preventative measures require an in­depth understanding of the processes, which the present research attempted to explain using examples of carbonate en­ crustations. 5. conclusion the study conducted from 2014 to 2017 revealed that in serbia there are sources of mineral water that exhibit numerous specific features with regard to their basic ionic composition, tempera­ ture, total dissolved solids, ph, and the like. encrustations were noted at all study locations (bogatić, lu­ kovska banja and vranjska banja), on wellheads and within zones of mineral water emergence. the results of macroscopic and optical assessments, as well as x-ray powder diffraction, in­ dicated a predominantly calcium carbonate composition of the encrustations, with calcite and aragonite detected at all the loca­ tions. quartz, albite, muscovite and clinochlore were also de­ tected at some of the locations. the study concluded that the physico­chemical composition of the mineral waters was a key driver of the onset and progress of encrustation. high water temperatures (> 60°c), ph levels from 6.6 to 8.0, elevated tds – from 600 to 1267 mg/l, and the dominance of the hco3 ­ ion (361.6 – 598.0 mg/l), along with a certain proportion of the ca2+ ion (12.8 – 83.2 mg/l), favour the formation of carbonate encrustations. in addition, the concentra­ tion of co2 in the mineral waters (50.5 – 194.2 mg/l free co2) is also important, as it contributes to carbonate precipitation by disturbing the carbonate balance in the mineral water solution. in addition, hydrogeochemical modeling confirmed that there was a correlation between the chemical composition of the mineral waters and the mineral composition of the encrustations or, in other words, that the minerals detected in the encrustations likely originated from the mineral waters. prognostic analyses corroborated a propensity for encrusta­ tion at all locations, given that all the studied occurrences of mi­ neral water were characterized by siryz˂7 and silang>0, indi­ cating carbonate encrustations. apart from encrustations, phototrophic microbial mats were found at all the sites, represented by cyanobacteria, chlorophyta and bacillariophyta, which, inter alia, can facilitate the creation, accumulation of minerals in encrustations, indirectly affecting the rate of carbonate precipitation. acknowledgement the serbian ministry of science has financially supported this research under contracts tr33053, oi176020 and oi176018. references appelo, c.a.j. & postma, d. (1994): geochemistry, groundwater and pollution (2nded.).– balkema publishers, rotterdam, 635 p. appelo, c.a.j. & postma, d. (2004): geochemistry, groundwater and pollution.– crc press, london, 683 p. arnórsson, e. (1989): deposition of calcium carbonate minerals from geothermal waters. theoretical considerations.– geothermics, 18/1–2, 33–39. doi: 10.1016/ 03756505(89)90007-2 brezonik, p. & arnold, w. (2011): water chemistry: an introduction to the chemistry of natural and engineered aquatic systems.– oxford university pres, usa, 765 p. brown, k.l. (2013): mineral scaling in geothermal power production.– united na­ tions university. buhmann, d. & dreybrodt, w. (1987): calcite dissolution kinetics in the system h2o – co2 – caco3 with the participation of foreign ions.– chemical geology, 64/1−2, 89–102. doi: 10.1016/00092541(87)90154−9. buik, n.a. & willemsen, g. (2006): clogging rate of recharge wells in porous me­ dia.– proceedings megastock, pomona, nj, usa. chafetz, h.s. & folk, l. (1984): travertines: depositional morphology and the bacterially constructed constituents.– j. sediment. res., 54, 289–316. chafetz, h.s. (1994): bacterially induced precipitates of calcium carbonate and lithification of microbial mats.– biostabilization of sediments, 149–163. de zwart, a.h. (2007): investigation of clogging processes in unconsolidated aquifers near water supply wells.– ponaen & looyen bv, delft. deberry, d.w. (1982): corrosion in potable water systems.– us environmental pro­ tection agency, office of drinking water, final report, austin, texas, usa. deed, m.e.r. & preene, m. (2015): managing the clogging of groundwater wells.– proceedings of the xvi ecsmge, geotechnical engineering for infrastructure and development, 2787–2792. doi:10.1680/ecsmge.60678 demir, m., baba, a., atilla v. & inanli, m. (2014): types of the scaling in hy­ per saline geothermal system in northwest turkey.– geothermics, 50, 1–9. doi: 10.1016/j.geothermics.2013.08.003 dolgorjav, o. (2009): geochemical characterization of thermal fluids from the khan­ gay area, central mongolia.– geothermal training programme reports, orkustofnun, grensásvegur, p. 9. donlan, r.m. (2002): biofilms: microbial life on surfaces.– emerging infectious diseases, 8/9, 881–890. doi: 10.3201%2feid0809.020063 dragišić, v. & polomčić, d. (2009): hidrogeološki rečnik.– university in bel­ grade, faculty of mining and geology, serbia. driscoll, f.g. (1986): groundwater and wells (2nded.).– johnson filtration systems inc., st. paul. edinger, s.e. (1973): an investigation of the factors which effect the size and growth rates of the habit faces of gypsum.– journal of crystal growth, 18/3, 217–224. doi: 10.1016/0022-0248(73)90164-4 filipović, b. (2003): mineralne, termalne i termomineralne vode srbije.– university in belgrade, faculty of mining and geology, serbia, 1–278. filipović, b., krunić, o. & lazić, m. (2005): regionalna hidrogeologija srbije.– university in belgrade, faculty of mining and geology, serbia, 401 p. flügel, e. (2004): microfacies of carbonate rocks.– springer berlin heidelberg, new york, 117–242. doi: 10.1007/978-3-662-08726-8_5 flügel, e. (2013): microfacies of carbonate rocks: analysis, interpretation and appli­ cation. – springer science & business media, 1–976. garcia, a.v., thomsen, k. & stenby, e.h. (2005): prediction of mineral scale formation in geothermal and oilfield operations using the extended uniquac model: part i. sulfate scaling minerals.– geothermics, 34/1, 61–97. doi: 10.1016/j. geothermics.2004.11.002 gallup, d.l. (2002): investigation on of organic inhibitors for silica scale control in geothermal brines.– geothermics, 31/4, 415–430. doi: 10.1016/s0375-6505(02) 00004-4 gavrilko, v.m. & alekseev, v.s.s. (1985): water wells screen.– publishing house nedra, moscow, 300–304. gill, j.s. (1998): silica scale control.– chem. treatment, 41–45. gunnlaugsson, e. & einarsson, j. (1989): magnesium-silicate scaling in mix­ ture of geothermal water and deaerated fresh water in a district heating system.– geothermics, 18/1–2, 113–120. doi: 10.1016/0375-6505(89)90017-5 gunnlaugsson, e., ármannsson, h., thorhalsson, s. & stein­ rímsson, b. (2014): problems in geothermal operation – scaling and corrosion.– goethermal training program, united nations university, 1–18. g eologia c roatica šaraba et al.: macroscopic, optical and diffraction assessment of encrustations and sem analyses of phototrophic microbial mats ... 161 guo, l. & riding, r. (1992): aragonite laminae in hot water travertine crusts, rapo­ lano terme, italy.– sedimentology, 39/6, 1067–1079. doi: 10.1111/j.1365-3091.1992. tb01997.x honegger, j.l., czernichowski-lauriol, i., criaud, a., menjoz, a., sainson, s. & guezennec, j. (1989): detailed study of sulfide scaling at la courneuuenord, a geothermal exploitation of the paris basin, france.– geother­ mics, 18/1–2, 137–144. doi: 10.1016/0375-6505(89)90020-5 houben, g. (2000): genesis, aging and chemical removal of well incrustations.– ap­ plied mineralogy in research, economy, technology, ecology and culture, 2, 803–806. houben, g. (2001): well ageing and its implications for well and piezometer perfor­ mance.– iahs publication, 297–302. houben, g.j. (2006): the influence of well hydraulics on the spatial distribution of wel l inc rus ta t ions .– groundwater, 44 /5 , 668–675 . do i : 10.1111/j.1745-6584.2006.00216.x houben, g. & treskatis, c. (2007): water well rehabilitation and reconstruction.– mcgraw-hill. houben, g.j. & weihe, u. (2010): spatial distribution of incrustations around a wa­ ter well after 38 years of use.– groundwater, 48/1, 53–58. doi: 10.1111/j.1745-6584.2009.00641.x howsam, p., misstear, b. & jones, c. (1995): monitoring, maintenance and re­ habilitation of water supply boreholes.– construction industry research and in­ formation association. jemcev, v. & đukić, d. (2000): mikrobiologija.– vojnoizdavački zavod, belgrade, 759 p. jones, b. & renaut, r.w. (2010): calcareous spring deposits in continental set­ tings.– development in sedimentology, 61/4, 177–224. doi: 10.1016/s00704571(09)06104-4 juránek, j., škollova, z. & harnová, j. (1987): “minequa” part i. a pro­ gram for computing the chemistry of calcium carbonate in mineralized and thermal waters.– geothermics, 16/3, 263–270. doi: 10.1016/0375-6505(87)90005-8 kaźmierczak, j., fenchel, t., kuhl, m., kempe, s., kremer, b., lacka, b. & malkowski, k. (2015): caco3 precipitation in multilayered cyanobacte­ rial mats: clues to explain the alternation of micrite and sparite layers in calcareous stromatolites.– life, 5/1, 744–769. doi: 10.3390/life5010744 kristmannsdóttir, h. (1989): types of scaling occurring by geothermal utiliza­ tion in iceland.– geothermics, 18/1–2, 183–190. doi: 10.1016/03756505(89)90026-6 krunić, o. (1999): termomineralne vode srbije – osnovni tipovi i karakteristike.– phd thesis, university in belgrade, faculty of mining and geology, serbia. krunić, o. (2012): mineralnevode.– university in belgrade, faculty of mining and geology, serbia, 1–384. langelier, w.f. (1936): the analytical control of anti-corrosion water treatment.– journal of american water works association, 28/10, 1500–1521. doi: 10.1002/ j.1551-8833.1936.tb13785.x lawrence, j.r. & caldwell, d.e. (1987): behavior of bacterial stream popula­ tions within the hydrodynamic boundary layers of surface microenvironments.– microbial ecology, 14/1, 15–27. doi: 10.1007/bf02011567 lazić, m. (2004): metode razrade i regeneracije bunara.– university in belgrade, faculty of mining and geology, serbia, 1–236. li, b. & logan, b.e. (2004): bacterial adhesion to glass and metal-oxide surfaces.– colloids and surfaces b: biointerfaces, 36/2, 81–90. doi: 10.1016/j.col­ surfb.2004.05.006 majkić, b. (2013): starenje bunara u aluvijalnim sredinama različitog stepena oksičnosti.– phd thesis, university in belgrade, faculty of mining and geology, serbia. majkić-dursun, b., petković, a. & zdravković-boreli, đ. (2016): po­ tencijal korozivnosti aluvijalnih podzemnih voda u slivu velike morave.– zaštita materijala, 57/3, 404–411. doi: 10.5937/zasmat1603404m martinović, m. & milivojević, m. (1998): the hydrogeothermal system of mačva and semberija.– in: geothermie: forshung entwicklung markt (tagungs­ band). geothermische fachtagung, straubing, 5, 133–141. martinović, m. (2012): mogućnost proizvodnje električne energije iz hidrogeoter­ malnih resursa na području surduličkog granitoidnog masiva.– in: xiv serbian symposium of hydrogeology with international participation, may 17-20, zlati­ bor. university in belgrade, faculty of mining and geology, belgrade, 203–209. milivojević, m. (1989): evaluation of geothermomineral resources of serbia terri­ tory-excluding autonomous provinces.– phd thesis, university of belgrade, faculty of mining and geology, serbia. mitić, n., stojiljković, d., todorović, ž., nikolić, lj., stojiljković, s. & cakić, s. (2014): physicochemical and geochemical characterization of geothermal waters sedimentation tendency at sijarinska spa and vranjska spa (ser­ bia).– hem. ind. 68 /1, 63–67. doi: 10.2298/hemind121002026m morozov, e.a. & mershchii, v.a. (1979): соодужение и эксплуатация водозаборныx скважин.– budivelnyk, kijev. mullin, j.w. (2001): crystallization.– elsevier, 587 p. noffke, n., eriksson, k.a., hazen, r.m. & simpson, e.l. (2006): a new win­ dow into early archean life: microbial mats in earth’s oldest siliciclastic tidal de­ posits (3.2 ga moodies group, south africa).– geology, 34/4, 253–256. doi: 10.1130/g22246.1 ogino, t., suzuki, t. & sawada, k. (1987): the formation and transformation mechanism of calcium carbonate in water.– geochemica et cosmochimica acta, 51/10, 2757–2767. doi: 10.1016/0016-7037(87)90155-4 ölçenoğlu, k. (1986): scaling in the reservoir in kizildere geothermal field, tur­ key.– geothermics, 15/5-6, 731–734. doi: 10.1016/0375-6505(86)90085-4 papić, p. (1999): inkrustacione i agresivne osobine mineralnih voda srbije.– phd the­ sis, university of belgrade, faculty of mining and geology, serbia. parkhurst, d.l. & appelo, c.a.j. (1999): user’s guide to phreeqc (version 2): a computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations.– denver, colorado: u. s. geological sur­ vey. pátzay, g., kármán, h.f. & póta, g. (2003): preliminary investigations of scal­ ing and corrosion in high enthalpy geothermal wells in hungary.– geothermics, 32/4–6, 627–638. doi: 10.1016/s0375-6505(03)00068-3 pedley, m. (1992): freshwater (phytoherm) reefs: the role of biofilms and their bear­ ing on marine reef cementation.– sedimentary geology, 79/1–4, 255–274. doi: 10.1016/0037-0738(92)90014-i perdikouri, c., kasioptas, a., geisler, t., schmidt, b.c. & putnis, a. (2011): experimental study of the aragonite to calcite transition in aqueous solu­ tion.– geochemica et cosmochimica acta, 75/20, 6211–6224. doi: 10.1016/j. gca.2011.07.045 perry, c.t. (1999): biofilm-related calcification, sediment trapping and constructive micrite envelopes: a criterion for the recognition of ancient grass-bed environ­ ments?– sedimentology, 46/1, 33–45. doi: 10.1046/j.1365-3091.1999.00201.x plummer, l.n., wigley, t.m.l. & parkhurst, d.l. (1978): the kinetics of cal­ cite dissolution in co2 water systems at 5 degrees to 60 degrees c and 0.0 to 1.0 atm co2.– american journal of science, 278/2, 179–216. doi: 10.2475/ ajs.278.2.179 plummer, l.n. & busenberg, e. (1982): the solubilitites of calcite, aragonite and vaterite in co2-h2o solutions between 0 and 90°c, and an evaluation of the aque­ ous model for the system caco3-co2-h2o.– geohemica cosmochimica acta, 46/6, 1011–1040. doi: 10.1016/0016-7037(82)90056-4 potapov, v.v., kashpura, v.n. & alekseev, v.i. (2001): a study of the growth of deposits in geothermal power systems.– therm. eng., 48/5, 395–400. protić, d. (1995): mineralne i termalne vode srbije.– geoinstitute, belgrade, serbia, 1–269. richards, c.s. (2016): calcium carbonate formation in water distribution systems and autogenous repair of leaks by inert particle clogging.– phd thesis, virginia tech. riding, r. (2000): microbial carbonates: the geological record of calcified bacterial – algal mats and biofilms.– sedimentology, 47, 179–214. doi: 10.1046/j.1365-3091.2000.00003.x ryznar, j.w. (1994): a new index for determining amount of calcium carbonate scale formed by a water.– j. am. water works assoc., 36/4, 472–486. schnieders, j.h. (2003): chemical cleaning, disinfection and decontamination of water wells.– johnson screens, 227 p. schwankl, l., hanson, b. & prichard, t. (2008): maintaining microirrigation systems.– ucanr publications (vol. 216137). seckbach, j. & oren, a. (2010): microbial mats: modern and ancient microorganisms in stratified systems.– springer science and business media, vol. 14. doi: 10.1007/978-90-481-3799-2 sterrett, r., mehmert, m. & hanna (2008): twenty years in the water well industry: where are we? – groundwater, 46/5, 659–659. doi: 10.1111/j.1745-6584.2008.00460.x stojiljković, d., cakić, s. & mitić, n. (2015): stvaranje depozita u instalaci­ jama sa geotermalnom vodom, tretman geotermalne vode elektromagnetskim poljem promenljive učestanosti u cilju sprečavanja stvaranja depozita.– faculty of technology, university in niš. szewzyk, u. & schink, b. (1988): degradation of hydroquinone gentisate and ben­ zoate by a fermenting bacterium in pure or defined mixed culture.– journal of arch. microbiol., 151/6, 541–545. šaraba, v., popović, s., krunić, o., subakov simić, g., kljajić, ž. & lazić, m. (2017): mineral waters of serbia and development of phototrophic microbial communities near points of emergence and on wellheads.– acta carso­ logica, 46/2–3, 295–316. doi: 10.3986/ac.v46i2-3.4961 tang, m., ehrresier, a. & li, y. (2014): gypsum in modern kamchatka volcanic hot springs and the lower cambrian black shale: applied to the microbial-medi­ ated precipitation of sulfates on mars.– american mineralogist, 99/10, 2126–2137. doi: 10.2138/am-2014-4754 tice, m.m. & lowe, d.r. (2006): hydrogen-based carbon fixation in the earliest known photosynthetic organisms.– geology, 34/1, 37–40. doi: 10.1130/g22012.1 g eo lo gi a c ro at ic a geologia croatica 72/2162 tišljar, j. (2001): sedimentologija karbonata i evaporita.– institut za geološka istraži vanja, zagreb, 375 p. van beek, k., breedveld, r., tas, m. & kollen, r. (2010): prevention of wellbore clogging by intermittent abstraction.– groundwater monitoring and remediation, 30/4, 81–89. doi: 10.1111/j.1745-6592.2010.01307.x van beek, c.k. (2011): cause and prevention of clogging of wells abstracting ground­ water from unconsolidated aquifers.– iwa publishing, 1–143. vuković, m. & soro, a. (1992): hydraulics of water wells: theory and application.– water resources pubblications. whitton, b.a. (2012): ecology of cyanobacteria ii: their diversity in space and time.– springer science and business media. woyessa, a.o. (2012): identification of hydrochemical processes in the screen en­ vironment in shallow geothermal wells from gardermoen.– unpubl. master the­ sis, university of oslo, faculty of mathematics and natural sciences. www.geologia-croatica.hr abstract the trepča pb-zn-ag skarn deposit in kosovo is spatially and temporarily related to the phreatomagmatic breccia of oligocene age (~23ma). the deposit shows features typical for skarn deposits worldwide, including a stage of isochemical metamorphism, a prograde stage of an anhydrous, low oxygen and low sulfur fugacity character, and a retrograde stage characterized by an increase in the water activity as well as by an increase in oxygen and sulfur fugacities. the mineralization is hosted by the recrystallized upper triassic limestone. the prograde mineralization consists mainly of ca-fe-mn±mg pyroxenes. the host recrystallized limestone at the contact with the prograde (skarn) mineralization has an increased content of fe, mn, mo, as, au, cs, ga, ree and y suggesting their transport by infiltrating magmatic fluids. the decreased d13c and d18o values reflect the contribution of magmatic co2. the retrograde mineral assemblage comprises ilvaite, magnetite, arsenopyrite, pyrrhotite, marcasite, pyrite, ca-fe-mn±mg carbonates and quartz. hydrothermal ore minerals, mostly galena, sphalerite and pyrite, were deposited contemporaneously with the retrograde stage of the skarn development. syn-ore and post-ore carbonates reflect the diminishing influence of magmatic co2. syn-ore carbonates are enriched in fe, mg, mn, many chalcophile elements, including ag, as, bi, cd, cu, pb, sb and zn, as well as in au, y and ree. the post-ore stage accompanied the precipitation of a significant amount of ca-rich carbonates including travertine deposits at the deposit surface. the phreatomagmatic breccia was developed along a nw dipping contact between the ore bearing recrystallized limestone and the overlying schist. it has an inverted cone shape with vertical extension up to 800 m and a diameter of up to 150 m. the upper part of the diatreme (an underground segment of the phreatomagmatic breccia) is characterized by the presence of a hydrothermally altered rootless quartz-latite dyke surrounded by an unsorted polymict breccia mantle. despite the alteration processes, the dyke has a preserved porphyritic texture. partly preserved sanidine, accompanied with a mixture of muscovite and quartz, reflects a near-neutral to weakly acidic environment. the clasts of country rocks and skarn mineralization underwent intense milling and mixing due to repeated magmatic penetrations. sericitization of the breccia matrix, locally accompanied with minor kaolinitization, point to an increased water activity under near-neutral to weakly acidic conditions. large fragments originally composed of anhydrous skarn minerals (pyroxenes) are usually completely altered to a mixture of fibroradial magnetite, quartz and various amounts of carbonates suggesting an increase in oxygen fugacity. their pyrite rims reflect that the increase in oxygen fugacity was followed by an increase in sulfur fugacity. the clast predominantly composed of fe-sulfides and minor bi-sulfides suggest that the increase in sulfur fugacity was locally sufficient to complete sulfidation of hedenbergite to pyrrhotite and/or pyrite. although the phreatomagmatic breccia at the trepča pb-zn-ag skarn deposit does not carry significant amounts of ore mineralization, its formation was crucial for ore deposition. phreatomagmatic explosions and formation of the breccia turned the system from the lithostatic to hydrostatic regime and triggered the retrograde stage increasing the water activity and oxygen fugacity in the system. in addition, cooling and decompression of the system contributed to more effective degassing of magmatic sulfur and increased the sulfur fugacity. doi:10.4154/gc.2016.10 keywords: phreatomagmatic breccia, pb-znag skarn deposit, transition from lithostatic to hydrostatic regime, fluid inclusions, stable isotopes, k/ar dating article history: received september 24, 2015 revised and accepted january 05, 2016 avaliable online february 29, 2016 121-142 12 figs. 4 tabs. origin and k-ar age of the phreatomagmatic breccia at the trepča pb-zn-ag skarn deposit, kosovo: implications for ore-forming processes sabina strmić palinkaš1,*, ladislav palinkaš2, magda mandić3, zvjezdana roller-lutz4, zoltan pécskay5, gani maliqi6 and vladimir bermanec2 1university of tromsø, faculty of science and technology, department of geology, dramsvegen 201, n-9037 tromsø, norway (*corresponding author, email: sabina.s.palinkas@uit.no) 2university of zagreb, faculty of science, geological department, horvatovac 95, hr-10000 zagreb, croatia 3thermo fisher scientific, hanna-kunath-straße 11, d-28199 bremen, germany 4university of rijeka, medical faculty, department of physics, braće branchetta 20, hr-51 000 rijeka, croatia 5institute of nuclear research, hungarian academy of sciences, bemtér 18/c, h-4001 debrecen, hungary 6prishtina university, faculty of mines and metallurgy, mitrovica, kosovo 122 vol. 69/1 1. introduction breccia pipes have been recognized in different types of ore deposits, from porphyry to epithermal in their origin (e.g. the acupan au-ag-te epithermal deposit, philippines (cooke & bloom, 1990); the roşia montană au-ag epithermal deposit, romania (wallier et al., 2006); the cerro de pasco epithermal polymetallic deposit, peru (baumgartner et al., 2008); the el teniente cu-mo porphyry deposit, chile (cannell et al., 2005; vry et al., 2010)). at some localities a genetic link between the breccia formation and ore mineralization is evident (e.g. the wau au deposit, papua new guinea (sillitoe et al., 1984); the kelian au deposit, indonesia (davies et al., 2008); the galore creek cu-au deposit, british columbia, canada (byrne & tosdal, 2014)), while at others it is more obscure. also, at some localities breccia pipes host significant amounts of ore (e.g. the aubearing breccia pipe at kidston, queensland, australia (baker & andrew, 1991); the cu-bearing donoso breccia pipe, chile (skewes et al., 2003); the base metal-bearing breccia pipe at the cerro de pasco deposit, peru (baumgartner et al., 2008)) whereas elsewhere they are mostly barren (the aguablanca ni-cu magmatic deposit, spain (tornos et al., 2001); the copper creek mining district, arizona, usa (anderson et al., 2009); the blackbird co-cu-au-bi-y-ree district, idaho, usa (trumbull et al., 2011)). the trepča deposit in kosovo (fig. 1) is an example of the pb-zn-ag skarn deposit spatially and temporarily related to the phreatomagmatic breccia (strmić palinkaš et al., 2007; féraud et al., 2007; strmić palinkaš et al, 2013). the deposit, with current reserves of 31 mt of ore at 4.2 % of pb, 3 % of zn and 86 g/t of ag, together with the past production of approximately 34 mt of ore, represents an important source of metals in the se part of europe. a nearly circular breccia pipe occurs at the contact between the mineralized recrystallized limestone of upper triassic age and the barren schist (fig. 2). although the breccia does not host an economically significant amount of ore, we argue that the mechanism of its formation is a key factor for understanding ore forming processes in the trepča deposit. the abandoned open pit and the active underground mine expose the breccia over a vertical interval of 800 m and allow access to various breccia lithofacies. the major aim of this study is to understand the origin of the phreatomagmatic breccia and its role in the ore-deposition processes at the trepča pb-zn-ag skarn deposit. the study combines descriptive features, mineralogy, stable isotope and fluid inclusion data obtained from the breccia and wall rocks. the k/ar data gained on whole rock and single grain separates revealed the age of the brecciation event. figure 1. geological setting of the pb-zn mineral deposits, including the trepča pb-zn-ag skarn deposit, within the vardar zone, se europe (simplified after karamata et al. (2000) and dimitrijević (2001)). external vardar zone: jb – jadar block and kb kopaonik block; cvz central vardar zone; ivz internal vardar zone; dob – dinaride ophiolite belt; dit – drina-ivanjica terrain; pz pelagonian zone; smm serbo-macedonian massif. figure 2. a. cross section through the trepča pb-zn-ag skarn deposit; b. local geological map of the trepča pb-zn-ag skarn deposit (after schumacher, 1950). 123 strmić palinkaš et al.: origin and k-ar age of the phreatomagmatic breccia at the trepča pb-zn-ag skarn deposit, kosovo: implications... 2. geological setting the trepča pb-zn-ag skarn deposit is situated in the western part of the nw-se trending vardar zone that extends throughout the western part of the balkan peninsula between the dinarides, the drina-ivanjica terrain and the pelagonian zone to the west and the serbo-macedonian massif to the east (fig. 1). the vardar zone represents the main suture zone along the contact between the adriatic and the euroasian plate with elements of both continental and oceanic lithologies (dimitrijević, 2001; karamata et al., 2000; zelić et al., 2010; robertson et al., 2013). during the late permian to middle triassic the incipient rifting process affected metamorphosed precambrian-palaeozoic terrains separating the pelagonian zone and the serbo-macedonian massif. rifting was followed by the development of a subsiding carbonate platform and formation of an oceanic crust during late triassic-early jurassic time (sharp & robertson, 2006; dilek et al., 2007; robertson et al., 2013). the western (external) vardar zone represents a complex zone that comprises ophiolites and ophiolitic mélange (karamata et al., 1980). at several localities ophiolitic masses, composed of spinel lherzolite, harzburgite and dunite, have preserved evidence for metamorphic soles at their bases. the k/ar age between 160 and 123 ma (karamata et al., 2000; milovanović et al., 1995) and ar/ar age between 175 and 170 ma (borojević šoštarić et al., 2014) obtained from the metamorphic soles suggest emplacement of ophiolites from the middle jurassic to the early cretaceous. the jurassic-cretaceous mélange of the western vardar zone comprises mostly large blocks and fragments of middle to upper triassic and upper jurassic limestones, terrigenous sediments (sandstone, greywacke), basalts, and figure 3. a. upper palaeozoic schist intercalated with quartzite layers; b. recrystallized upper triassic limestone with developed karst phenomena; c. prograde skarn mineralization consisting mainly of pyroxenes; d. retrograde skarn mineralization comprising a mixture of ilvaite, magnetite, quartz and ca-fe-mn-mg carbonates; e. hydrothermal mineralization comprising ore (galena, sphalerite, pyrite) and gangue (carbonate, quartz) minerals; f. the principal ore minerals, galena and sphalerite, are accompanied by various amounts of pyrite; g. travertine deposits at the surface of the trepča pb-zn-ag skarn deposit (835 m above mean sea level); h. close view of the travertine deposit; i. photomicrographs of trachyte with typical porphyritic texture and altered sanidine phenocrysts (under crossed polarizers); j. photomicrographs of quartz-latite with altered sanidine, plagioclases, amphiboles and quartz as principal phenocrysts (under crossed polarizers); k. photomicrographs of andesite composed of plagioclase, amphiboles and quartz phenocrysts embedded within a carbonized and silificated aphanitic groundmass. mineral abbreviations: hd – hedenbergite; mt – magnetite, ilv – ilvaite; carb – ca-fe-mn-mg carbonates; qtz – quartz; sph – sphalerite; gn – galena; py – pyrite. 124 vol. 69/1 cherts with carnian to norian and upper jurassic radiolarians emplaced within an argillaceous to silty matrix (sudar & kovacs, 2006; vasković & matović, 2010). in contrast, the eastern (internal) vardar zone comprises the weakly metamorphosed mélange of jurassic age with predominantly basaltic fragments (sudar & kovacs, 2006, and references therein). the postcollisional magmatism of oligocene to miocene age (cvetković et al., 2004) was accompanied by widespread hydrothermal activity in the western vardar zone, producing numerous skarn, hydrothermal replacement and vein type pb-zn-ag deposits (fig. 1; janković, 1995; veselinovićwilliams, 2011; borojević šoštarić et al., 2013; strmić palinkaš et al., 2013). the oligocene to miocene magmatic rocks is represented mostly by trachytes, quartz-latites, andesites and pyroclastic deposits (cvetković et al., 2004; borojević šoštarić et al., 2012). 2.1. geology of the deposit the basement of the trepča pb-zn-ag skarn deposit comprises a metamorphosed and folded upper palaeozoic to triassic sedimentary complex composed predominantly of schist and recrystallized limestone. the dark coloured schist occasionally is intercalated with compact dense to coarse-grained quartzite layers (fig. 3a). at the contact with the mineralization the schist is enriched in quartz and micas. the recrystallized limestone frequently exhibits developed karst phenomena (fig. 3b). the size of calcite grains varies from several millimetres at places spatially distal to the mineralization up to several centimeters along the contact with the ore bodies and the breccia pipe. according to the data obtained from conodont remains the limestone has been assigned to the upper figure 4. a. pyroclastic rocks enclose euhedral calcite crystals, fragments of the country rocks and spheroid pumice lapillus. the leaves and plant root traces are also visible; b. lateral dykelike branches of the main breccia pipe sporadically intrude the recrystallized upper triassic limestone; c. a gradual transition from the main breccia pipe into the brecciated schist; d. hydrothermally altered quartz-latite from the core of the main breccia pipe. white fine-grained matrix incorporates yellowish to greenish remains of sanidine phenocrysts, quartz phenocrysts and fragments of country rocks, predominantly the schist; e. randomly oriented fragments of schist (s), recrystallized limestone (l) and magnetite and pyrite-bearing clasts (m-p), the main breccia pipe, surface (835 m above mean sea level); f. close view of the clast composed of a magnetite core and pyritic rim; g. photomicrographs of the clast composed of a fibroradial magnetite core and pyritic rim (plane-polarized light); h. scanning electron photomicrograph of the clast composed of a magnetite core and pyritic rim reveals the presence of bi-telluride and bisulfide; i. recrystallized limestone (l) fragment partly replaced with fibroradial arsenopyrite and magnetite (75 m above mean sea level); j. the clast composed of pyrite, pyrrhotite and minor bi-sulfides. mineral abbreviations: mt – magnetite; py – pyrite; po – pyrrhotite, apy – arsenopyrite; carb – ca-fe-mn-mg carbonates; qtz – quartz. 125 strmić palinkaš et al.: origin and k-ar age of the phreatomagmatic breccia at the trepča pb-zn-ag skarn deposit, kosovo: implications... triassic (sudar, 1986). the limestone-schist contact is marked by the presence of the breccia pipe (schumacher, 1950, 1954; féraud et al., 2007; strmić palinkaš et al., 2013). the mineralization of the trepča pb-zn-ag skarn deposit is exclusively hosted by the recrystallized limestone (fig. 2). the principal skarn minerals in the trepča deposit are ca-femn±mg silicates including pyroxenes, ilvaite and minor garnets. accessory minerals are ca-fe-mn±mg carbonates and quartz. paragenetic studies based on macroand microtextures show that the skarn assemblage from the trepča deposit was formed in several stages, similar to other skarns (meinert, 1992; malo et al., 2000; meinert et al., 2005; canet et al, 2011). the prograde stage has an anhydrous character with ca-fe-mn±mg pyroxenes as the major minerals (fig. 3c). cafe garnets (andradite) occur rarely, exclusively in the uppermost levels of the deposit. the retrograde stage has a predominantly hydrous character with ilvaite, magnetite, carbonate and quartz as important products (fig. 3d). the hydrothermal ore minerals commonly overprint the pyroxene-rich calcic skarn, although skarn mineralization free of the ore assemblage as well as the ore mineralization without skarn precursor has been found (fig. 3e). black coloured sphalerite, galena and pyrite are the most abundant sulfide minerals (fig. 3f). the deposit contains volumetrically minor, but mineralogically diverse bi-bearing minerals, including native bi, bismuthinite (bi2s3), cosalite (pb2bi2s5), cannizzarite (pb4bi6s13), lillianite (pb3bi2s6), ikunolite (bi4(s,se)3), babkinite (pb2bi2(s,se)3), joseite (bi4(s,te)3), heyrovskyite (pb10agbi5s18) andizoklakeite (pb27(cu,fe)2(sb,bi)19s57) (terzić et al., 1974; kołodziejczyk et al., 2015). travertine deposits locally occur as a top layer capping the deposit and marking the preserved palaeosurface (figs. 3g, h). during the oligocene-miocene, the trepča area was a location of considerable volcanicactivity characterized by numerous lava flows and large masses of volcanoclastic rocks. the volcanic rocks are represented mostly by trachytes, quartzlatites and andesites. trachytes are composed of a light gray matrix and sanidine phenocrysts (fig. 3i). quartz-latites are exposed at the zvečan hill and occur as the core of the breccia pipe within the deposit. beside sanidine they comprise significant amounts of quartz grains (fig. 3j). the ar/ar age of the zvečan hill quartz-latite spans between 24.8±0.2 ma for kfeldspar and 25.8±0.3 ma for amphibole (borojević šoštarić et al., 2012). andesites are mainly light to medium gray in colour and porphyritic in texture. they are composed of plagioclase, hornblende, biotite, augite and bronzite (fig. 3k). 2.2 the breccia geometry, composition and internal organization the breccia pipe exposed at the trepča pb-zn-ag skarn has an inverted cone shape characteristic for phreatomagmatic breccias elsewhere (e.g. sillitoe, 1985; tamas & milesi, 2002; landtwing et al., 2002; davies et al., 2008). the diatreme (an underground segment of the phreatomagmatic breccia; lorenz, 1973) extends vertically up to 800 m below the surface and has a diameter of approximately 150 m (fig. 2). the partly preserved maar structure (a surface expression of phreatomagmatic breccia; lorenz, 1973) comprises tuffaceous (fig. 2; schumacher, 1950) and pyroclastic deposits with common remnants of plant leaves and roots (fig. 4a). the breccia pipe was emplaced along a nw dipping contact between the ore bearing recrystallized limestone and the overlying schist (fig. 2). contacts between the breccia and the recrystallized limestone are mostly sharp but locally cut by lateral dyke-like branches (fig. 4b) infilled with rock flour (“milled matrix fluidized breccia”) or with angular fragments (“jigsaw-puzzle breccia”). in contrast, the contacts with the overlying schist are unclear, with a gradual transition from the breccia pipe into the brecciated schist (fig. 4c). the upper part of the diatreme hosts a hydrothermally altered quartz-latite dyke with the preserved porphyritic texture (fig. 4d). the white fine-grained matrix comprises muscovite, quartz, and k-feldspars (fig. 5). the sanidine phenocrysts are partly altered to a yellowish to greenish fine-grained mixture of muscovite and quartz (fig. 5). the quartz phenocrysts are well preserved. fragments of county rocks, especially schist, are embedded within the matrix too. the dyke occupies the pipe core and is surrounded by the unsorted polymict breccia mantle (figs. 2, 4e). figure 5. x-ray diffraction patterns reveal that a. hydrothermally altered quartz-latite matrix consists of k-feldspar, quartz and muscovite; b. altered phenocrysts comprise sanidine remains as well as various micas and quartz. 126 vol. 69/1 sample level depth (m a.m.s.l.*) description km-10 surface 835 host limestone, barren, recrystallized p1 surface 835 pyroclastic deposit p2 surface 835 pyroclastic deposit p4 surface 835 travertine deposit tr-6 surface 835 quartz-latite tr-108 surface 835 hydrothermally altered quartz-latite core of the main breccia pipe km7-1 surface 835 fragment composed of a magnetite core and a pyrite rim, the main breccia pipe km8 surface 835 fragment composed of a magnetite core and a pyrite rim, the main breccia pipe km9 surface 835 fragment composed of fractured pyrite, pyrrhotite and minor bi-sulfides, the main breccia pipe tr-v-1 v 375 hydrothermal paragenesis tr-vii-7 vii 255 hydrothermal paragenesis tr-viii-2 viii 195 hydrothermal paragenesis tr-viii-4 viii 195 hydrothermal paragenesis t8 ix 135 hydrothermal paragenesis t8a ix 135 hydrothermal paragenesis t8-2 ix 135 hydrothermal paragenesis sts-0 x 75 host limestone, barren, recrystallized sts-1 x 75 hydrothermal paragenesis sts-2 x 75 hydrothermal paragenesis sts-3 x 75 hydrothermal paragenesis t1 x 75 clast composed of siderite, quartz and dickite, the main breccia pipe t2 x 75 recrystallized limestone fragment, the main breccia pipe sample level depth (m a.m.s.l.*) description t2 x 75 recrystallized limestone fragment partly replaced by magnetite and aresenopyrite, the main breccia pipe t3 x 75 the recrystallized limestone in contact with the main breccia pipe t3a x 75 the recrystallized limestone in contact with the main breccia pipe t4 x 75 recrystallized limestone at the contact with lateral breccia branches t4a x 75 lateral breccia branch t5 x 75 hydrothermal paragenesis t6a x 75 skarn paragenesis t6b x 75 skarn paragenesis t6c x 75 skarn paragenesis t6d x 75 skarn paragenesis t6e x 75 skarn paragenesis t6f x 75 host limestone, barren, recrystallized t7-2 x 75 hydrothermal paragenesis t7-3a x 75 hydrothermal paragenesis t7-4 x 75 recrystallized limestone at the contact with lateral breccia branches t7-4a x 75 lateral breccia branch t7-5 x 75 hydrothermal paragenesis t9-1 x 75 skarn paragenesis t9-3 x 75 skarn paragenesis t9-4 x 75 skarn paragenesis t9-5 x 75 hydrothermal paragenesis t9-6 x 75 skarn paragenesis 148a x 75 hydrothermal paragenesis tr-xi-2 xi 15 hydrothermal paragenesis tr-xi-3 xi 15 hydrothermal paragenesis tr-xi-4 xi 15 hydrothermal paragenesis tr-xi-5 xi 15 hydrothermal paragenesis tr-xi-6 xi 15 hydrothermal paragenesis table 1. analyzed samples from the trepča pb-zn-ag skarn deposit. * a.m.s.l. – above mean sea level * a.m.s.l. – above mean sea level 127 strmić palinkaš et al.: origin and k-ar age of the phreatomagmatic breccia at the trepča pb-zn-ag skarn deposit, kosovo: implications... clasts are angular to well-rounded ranging in size from less than a millimetre to several metres with no systematic distribution in fragment size and roundness. they occupy up to 90 vol.% of the breccia. fragments of the country rocks, limestones and schists, together with ca-fe-mn±mg silicate-, magnetiteand sulfide-bearing fragments represent the principal types of clasts. the upper portion of the diatreme is characterized by the extreme mixing of the rock fragments of various origin but besides the country rock fragments, the fragments composed of the magnetite core and pyrite-enriched rim are the most frequent. magnetite occurs in the form of fibroradial to spherulitic aggregates (fig. 4f) with minor masses of pyrite, bi-sulfides, bi-tellurides, carbonates and quartz emplaced between magnetite grains (figs. 4g, h). the rim comprises fresh pyrite accompanied by carbonates and quartz (figs. 4f, g). fragments of pyroclastic rocks and fragments with lacustrine plant remains have been found at various depths suggesting collapse events (mccallum, 1985; baker et al., 1986). in the deeper part of the breccia pipe, magnetite and overprinting fibroradial arsenopyrite are found to be embedded within recrystallized limestone fragments (fig. 4i). the clasts composed of fractured pyrite, pyrrhotite and minor bi-sulfides are common at various depths of the breccia pipe. the space between sulfide grains is filled with a fine-grained mixture of carbonates and quartz (fig. 4j). quartz-latite (juvenile) fragments occur as well. the breccia matrix comprises a finegrained rock flour that has been affected by various types of hydrothermal alterations, including sericitization, kaolinitization, pyritization and carbonatization. 3. samples and methods a total of forty-nine hand-picked rock samples were collected from existing underground works and from the surface of the trepča pb-zn-ag skarn deposit. we sampled various types of breccia fragments, wall rocks as well as mineral parageneses (table 1). paragenetic relationships were studied in thin sections by transmitted polarized light microscopy. ore minerals were examined in polished thick sections by reflected light microscopy. x-ray powder diffraction (xrd) analysis was conducted at the university of zagreb on a philips pw 3040/60 x’pert pro powder diffractometer (45 kv, 40 μa), with cukαmonochromatized radiation (λ = 1.54056 å) and θ-θ geometry. the area between 4 and 63° 2θ, with 0.02° steps, was measured with a 0.5° primary beam divergence. compound identifications were based on a computer program x’pert high score 1.0b and literature data. the textural features and semiquantitative analyses of breccia fragments were examined by a tescan scanning electron microscope (sem) equipped with an inca 250 analyzing system and oxford detectors at the university of zagreb. the analyses were performed on carbon-coated polished thin sections using the following operating conditions: 3-40 mm beam, accelerating voltage 20 kv, current 10 na and counting time of 200 seconds. bulk chemical compositions of 14 selected samples were prepared in an agate ball mill and analyzed at acme analytical laboratories (vancouver, canada) after lithium metaborate or tetraborate fusion using inductively coupled plasma (icp) for major elements and inductively coupled plasma-mass spectrometry (icp-ms) for trace elements. microthermometric measurements of fluid inclusions within transparent minerals (calcite, quartz) were performed at the university of zagreb. double polished, ~0.5-mm-thick, transparent mineral wafers were used. measurements were carried out on a linkam thms 600 stage mounted on an olympus bx 51 microscope using 10× and 50× olympus long-working distance objectives for visible light. two synthetic fluid inclusion standards (syn flinc; pure h2o and mixed h2o-co2) were used to calibrate the equipment. the precision of the system was ±2.0°c for homogenization temperatures, and ±0.2°c in the temperature range between –60° and +10°c. microthermometric measurements were made on carefully defined fluid inclusion assemblages, representing groups of inclusions that were trapped simultaneously. the fluid inclusion assemblages were identified based on petrography prior to heating and freezing. if all of the fluid inclusions within the assemblage showed similar homogenization temperatures, the inclusions were assumed to have trapped the same fluid and to have not been modified by leakage or necking; these fluid inclusions thus record the original trapping conditions (goldstein & reynolds, 1994; goldstein, 2001; bodnar, 2003). carbon and oxygen isotope analyses of carbonates from the wall rocks and breccia fragments as well as analyses of carbonates associated with the ore mineralization were performed at the university of rijeka. carbonate powder was extracted from hand-picked samples using a dentist’s drill. a mass of 250 μg of powder has been loaded in sealed reaction vessels, then flushed with helium gas and reacted at 72°c with phosphoric acid. the evolved carbon dioxide was sampled using a thermo finnigan gas-bench and isotope ratios were measured in continuous flow mode using a thermo finnigan deltaplus xpmass spectrometer. the data was extracted into an excel file by using the isodat nt excel export utility and further calculation steps were carried out using a predefined excel worksheet. linearity corrections were apfigure 6. the post-archean australian shale (paas) normalized plots of the recrystallized limestone at the contact with the main breccia pipe and the recrystallized limestone clast from the main breccia pipe (75 m above mean sea level). the data for the schist and barren limestone are adopted from strmić palinkaš et al. (2013). 128 vol. 69/1 table 2. chemical composition of carbonates from the trepča pb-zn-ag skarn deposit. sio2 al2o3 fe2o3 mgo cao na2o k2o tio2 p2o5 mno cr2o3 % ppm barren recrystallized limestone sts-0* recrystallized limestone 0.22 0.07 0.07 0.41 55.69 0.01 0.04 0.01 0.01 0.01 0.001 km10* recrystallized limestone 0.13 0.03 0.07 0.08 56.77 0.01 0.04 0.01 0.01 0.03 0.001 t6f* recrystallized limestone 0.06 0.03 0.09 0.11 56.24 0.01 0.04 0.01 0.01 0.10 0.001 recrystallized limestone at contact with the breccia t7-4* contact with the milled matrix breccia 0.14 0.03 0.09 0.15 55.91 0.01 0.04 0.01 0.01 0.09 0.001 t-3a contact with the main breccia pipe 0.35 0.03 0.54 0.3 54.37 0.01 0.04 0.01 0.03 0.92 0.001 recrystallized limestone clast from the breccia t-2 recrystallized limestone clast 0.23 0.08 0.31 0.34 55.18 0.01 0.04 0.01 0.01 0.27 0.001 recrystallized limestone at contact with the mineralization t6e* recrystallized limestone at contact with skarn mineral assemblage 0.16 0.03 0.74 0.11 52.92 0.01 0.04 0.01 0.01 3.67 0.001 t9-5* recrystallized limestone at contact with hydrothermal mineral assemblage 0.08 0.03 0.16 0.23 55.75 0.01 0.04 0.01 0.01 0.47 0.001 syn-ore carbonates t6a-1* syn-ore carbonates, skarn mineral assemblage 0.04 0.03 13.69 4.54 35.03 0.01 0.04 0.01 0.01 5.72 0.001 t9-5 (4)-1* syn-ore carbonates, hydrothermal mineral assemblage 0.09 0.03 9.45 5.79 34.14 0.01 0.04 0.01 0.01 10.32 0.001 post-ore carbonates t6a-2* post-ore carbonates, skarn mineral assemblage 0.04 0.03 0.85 0.23 53.66 0.01 0.04 0.01 0.01 2.46 0.001 t7-2* post-ore carbonates, hydrothermal mineral assemblage 0.05 0.03 0.16 0.22 54.04 0.01 0.04 0.01 0.01 2.88 0.001 t8a* post-ore carbonates, hydrothermal mineral assemblage 0.04 0.03 0.74 0.25 53.29 0.01 0.04 0.01 0.01 3.19 0.001 t9-5 (4)-2* post-ore carbonates, hydrothermal mineral assemblage 0.10 0.03 0.36 0.30 54.54 0.01 0.04 0.01 0.01 2.77 0.001 mo cu pb zn ni as cd sb bi ag hg % ppm barren recrystallized limestone sts-0* recrystallized limestone <d.l. 0.9 5.1 7 1.3 0.9 0.2 0.1 <d.l. <d.l. <d.l. km10* recrystallized limestone <d.l. 0.3 6.1 16 2.1 1.2 0.2 0.1 <d.l. <d.l. 0.01 t6f* recrystallized limestone 0.1 0.3 6.8 6 1.7 <d.l. 0.1 0.2 <d.l. <d.l. 0.02 recrystallized limestone at contact with the breccia t7-4* contact with the milled matrix breccia <d.l. 0.4 30.6 12 2.4 1.5 0.3 0.6 <d.l. <d.l. 0.01 t-3a contact with the main breccia pipe 0.1 0.9 12.2 10 0.2 31.1 0.1 0.5 0.1 <d.l. <d.l. recrystallized limestone clast from the breccia t-2 recrystallized limestone clast 0.1 0.2 25.9 8 1.3 40.9 0.1 0.4 1.0 0.2 0.01 recrystallized limestone at contact with the mineralization t6e* recrystallized limestone at contact with skarn mineral assemblage 0.3 0.2 6.7 3 1.0 2.2 <d.l. 0.1 <d.l. <d.l. <d.l. t9-5* recrystallized limestone at contact with hydrothermal mineral assemblage 0.1 0.4 7.2 10 3.4 <d.l. 0.2 0.3 <d.l. <d.l. 0.01 syn-ore carbonates t6a-1* syn-ore carbonates, skarn mineral assemblage 0.4 0.4 26.3 49 0.1 62.9 0.3 1.3 0.1 <d.l. 0.01 t9-5 (4)-1* syn-ore carbonates, hydrothermal mineral assemblage 0.9 79.5 399.9 238 <d.l. 727.0 1.6 7.9 0.1 0.8 0.01 post-ore carbonates t6a-2* post-ore carbonates, skarn mineral assemblage 0.2 0.1 15.0 11 0.4 6.2 0.1 0.5 0.1 <d.l. 0.02 t7-2* post-ore carbonates, hydrothermal mineral assemblage 0.3 1.9 600.5 111 1.2 14.8 0.9 2.1 <d.l. 1.1 <d.l. t8a* post-ore carbonates, hydrothermal mineral assemblage 0.3 0.2 8.8 26 0.4 6.3 0.2 0.9 <d.l. <d.l. <d.l. t9-5 (4)-2* post-ore carbonates, hydrothermal mineral assemblage 0.2 0.2 53.3 60 0.1 1.2 0.5 0.2 <d.l. <d.l. 0.01 <d.l. below detection llimit * major element and ree content adopted from strmić palinkaš et al. (2013) 129 strmić palinkaš et al.: origin and k-ar age of the phreatomagmatic breccia at the trepča pb-zn-ag skarn deposit, kosovo: implications... table 2. chemical composition of carbonates from the trepča pb-zn-ag skarn deposit. ba cs ga rb sr th u w zr y la % ppm barren recrystallized limestone sts-0* recrystallized limestone 7.0 <d.l. <d.l. 0.7 243 0.2 <d.l. <d.l. 1.6 2.6 1.3 km10* recrystallized limestone 3.3 <d.l. 0.8 0.6 153.1 <d.l. <d.l. <d.l. 0.7 0.8 0.8 t6f* recrystallized limestone 6.0 <d.l. 1.7 0 210 <d.l. 0.3 <d.l. 0.8 0.8 0.8 recrystallized limestone at contact with the breccia t7-4* contact with the milled matrix breccia 2.3 <d.l. 0.6 0.7 332.4 <d.l. 0.2 <d.l. 0.5 0.6 <d.l. t-3a contact with the main breccia pipe 4.7 <d.l. <d.l. 1.3 164.4 <d.l. 0.1 0.2 1.0 4.1 2.1 recrystallized limestone clast from the breccia t-2 recrystallized limestone clast 7.4 <d.l. <d.l. 0.8 200.8 <d.l. <d.l. 0.3 1.3 1.2 0.9 recrystallized limestone at contact with the mineralization t6e* recrystallized limestone at contact with skarn mineral assemblage 5.1 0.3 2.6 <d.l. 64.1 <d.l. <d.l. <d.l. <d.l. 36.9 28.6 t9-5* recrystallized limestone at contact with hydrothermal mineral assemblage 6.1 0.1 <d.l. 0.8 108.2 <d.l. 0.2 <d.l. 1.2 3.0 1.4 syn-ore carbonates t6a-1* syn-ore carbonates, skarn mineral assemblage 3.9 0.5 1.6 <d.l. 104 <d.l. 0.1 0.9 <d.l. 27.4 17.0 t9-5 (4)-1* syn-ore carbonates, hydrothermal mineral assemblage 14.1 0.1 1.2 <d.l. 120.1 <d.l. <d.l. 0.2 <d.l. 9.5 4.4 post-ore carbonates t6a-2* post-ore carbonates, skarn mineral assemblage 9.4 <d.l. <d.l. <d.l. 328.3 0 0.8 <d.l. <d.l. 4.5 0.9 t7-2* post-ore carbonates, hydrothermal mineral assemblage 5.2 <d.l. <d.l. <d.l. 229.7 0 0.2 0.2 <d.l. 2.9 0.8 t8a* post-ore carbonates, hydrothermal mineral assemblage 4.3 <d.l. 0.6 <d.l. 181.2 0 0.5 <d.l. 0.5 5.7 2.1 t9-5 (4)-2* post-ore carbonates, hydrothermal mineral assemblage 2.9 <d.l. 1.2 <d.l. 316.3 0 0.3 <d.l. <d.l. 8.3 2.1 ce pr nd sm eu gd tb dy ho er tm % ppm barren recrystallized limestone sts-0* recrystallized limestone 1.2 0.24 0.9 0.2 <d.l. 0.39 0.05 0.18 0.05 0.16 <d.l. km10* recrystallized limestone 0.6 0.08 <d.l. <d.l. <d.l. 0.07 0.01 0.06 <d.l. <d.l. <d.l. t6f* recrystallized limestone <d.l. 0.06 <d.l. <d.l. <d.l. 0.06 0.02 0.05 <d.l. 0.05 <d.l. recrystallized limestone at contact with the breccia t7-4* contact with the milled matrix breccia <d.l. 0.05 <d.l. <d.l. <d.l. <d.l. <d.l. 0.06 <d.l. <d.l. <d.l. t-3a contact with the main breccia pipe 4.2 0.51 2.1 0.5 0.48 0.63 0.10 0.51 0.10 0.32 <d.l. recrystallized limestone clast from the breccia t-2 recrystallized limestone clast 0.9 0.12 0.6 <d.l. 0.08 0.10 0.01 0.08 <d.l. 0.09 <d.l. recrystallized limestone at contact with the mineralization t6e* recrystallized limestone at contact with skarn mineral assemblage 67.7 8.41 37.0 8.9 6.50 8.67 1.24 7.13 1.19 3.00 0.35 t9-5* recrystallized limestone at contact with hydrothermal mineral assemblage 0.5 0.23 0.9 0.2 0.14 0.25 0.05 0.26 0.08 0.20 <d.l. syn-ore carbonates t6a-1* syn-ore carbonates, skarn mineral assemblage 26.4 2.92 11.2 3.0 6.46 3.52 0.68 4.36 0.84 2.48 0.31 t9-5 (4)-1* syn-ore carbonates, hydrothermal mineral assemblage 7.6 0.92 3.8 1.3 3.35 1.70 0.24 1.41 0.24 0.59 0.08 post-ore carbonates t6a-2* post-ore carbonates, skarn mineral assemblage 1.7 0.20 1.4 0.3 0.52 0.54 0.08 0.50 0.11 0.41 0.05 t7-2* post-ore carbonates, hydrothermal mineral assemblage 1.2 0.13 0.8 0.1 0.26 0.39 0.05 0.35 0.08 0.21 <d.l. t8a* post-ore carbonates, hydrothermal mineral assemblage 3.1 0.42 1.8 0.4 0.50 0.88 0.11 0.66 0.14 0.38 0.06 t9-5 (4)-2* post-ore carbonates, hydrothermal mineral assemblage 3.2 0.46 1.9 0.6 1.25 1.07 0.18 1.03 0.24 0.66 0.08 <d.l. below detection llimit * major element and ree content adopted from strmić palinkaš et al. (2013) 130 vol. 69/1 plied based on the relationships between the intensity of the first sample peak (m/z = 44) and δ18o values of the standards. due to calibration based directly on the carrara marble standard, which were part of each run, correction for calcite runs was unnecessary. the stable carbon and oxygen isotope ratios are reported in the delta (d) notation as per mil (‰) deviation relative to the vienna standard mean ocean water (v-smow) for oxygen and vienna pee dee belemnite (v-pdb) for carbon. the analytical precision was better than ±0.05‰ for δ13c and ±0.1‰ for δ18o. k/ar dating was undertaken at the institute of nuclear research of the hungarian academy of science (atomki), debrecen. the whole rock samples were crushed to 0.063-0.315 mm size. sanidine phenocrysts were hand-picked. one aliquot of samples (100 mg) was pulverized for potassium determination. powders were digested in hf with the addition of some sulfuric and perchloric acids. the digested samples were dissolved in 100 ml 0.25 mol/1 hcl and diluted fivefold. na and li (100 ppm) were added as buffer and internal standard. the potassium concentration was measured with a digitalized flame photometer. another aliquot of samples (500 mg) was used for ar analyses. the samples were degassed by highfrequency induction heating, and the conventional getter materials were used for cleaning ar. the 38ar spike was introduced to the system from a gas pipette before degassing. the cleaned ar was directly introduced into the mass spectrometer, operated in the static mode. recording and evolution of ar spectra was controlled by a microcomputer. details of the instruments, the applied methods and results of calibration have been described by balogh (1985). 4 results 4.1. geochemistry of carbonates the major element and ree contents of carbonates from the trepča deposit are given in strmić palinkaš et al. (2013). in this publication we refer to those data and present new unpublished trace element data obtained on the same set of samples (table 2). in addition, the recrystallized limestone from the contact with the breccia pipe and a fragment of recrystallized limestone hosted by the breccia has been analyzed (table 2). the barren recrystallized upper triassic limestone (samples sts-0, km10 and t6f) is characterized by a high cao content (~56 wt. %) and a low content of aluminosilicate impurities (sio2< 0.22 wt. %, al2o3< 0.07 wt. %). large-ionlithophile elements display low concentrations with an expected exception of sr (210-332 ppm). the ree concentrations are mostly below their detection limits, precluding estimation of complete ree patterns for this group of carbonates. the recrystallized limestone in contact with the breccia pipe (t3a) shows an increase in mno (0.9 wt. %), fe2o3 (0.5 wt. %), sio2 (0.35 wt. %), as (31.1 ppm), pb (12.2 ppm), y (4.1 ppm), sb (0.5 ppm), w (0.2 ppm) and ree content (sree = 11.8 ppm). it exhibits the roof-shaped paas-normalized ree concentration pattern with a very negative cen and a strong positive eun anomaly (fig. 6). the chemical composition of the recrystallized limestone in contact with the lateral branches of the main breccia pipe (t7-4) shows overlapping with the values obtained for the barren recrystallized limestone. however, some trace elements, including pb (30.6 ppm), ni (2.4 ppm), as (1.5 ppm), cd (0.3 ppm), and sb (0.6 ppm) are more abundant than in the barren limestone. whereas the majority of ree have concentrations below their detection limits, the ree pattern cannot be plotted. the fragments of recrystallized limestone hosted by the breccia (t2) are slightly enriched in mno (0.3 wt. %), fe2o3 (0.3 wt. %), pb (25.9 ppm), as (40.9 ppm), sb (0.4 ppm), ag (0.2 ppm), au (1 ppb), tl (0.1 ppm), and w content (0.3 ppm) comparing to the barren recrystallized upper triassic limestone. the complete ree pattern cannot be estimated due to concentrations of sm, dy, tm and lu below their detection limits, the obyb lu sum ree au % ppm ppb barren recrystallized limestone sts-0* recrystallized limestone 0.13 0.03 4.83 0.5 km10* recrystallized limestone <d.l. <d.l. 1.62 <d.l. t6f* recrystallized limestone 0.05 0.01 1.1 0.5 recrystallized limestone at contact with the breccia t7-4* contact with the milled matrix breccia <d.l. <d.l. 0.11 <d.l. t-3a contact with the main breccia pipe 0.25 0.03 11.83 <d.l. recrystallized limestone clast from the breccia t-2 recrystallized limestone clast 0.11 <d.l. 2.99 1.0 recrystallized limestone at contact with the mineralization t6e* recrystallized limestone at contact with skarn mineral assemblage 1.69 0.25 180.63 1.1 t9-5* recrystallized limestone at contact with hydrothermal mineral assemblage 0.13 0.03 4.37 <d.l. syn-ore carbonates t6a-1* syn-ore carbonates, skarn mineral assemblage 2.03 0.23 81.43 3.9 t9-5 (4)-1* syn-ore carbonates, hydrothermal mineral assemblage 0.51 0.06 26.2 16.6 post-ore carbonates t6a-2* post-ore carbonates, skarn mineral assemblage 0.28 0.03 7.02 1.1 t7-2* post-ore carbonates, hydrothermal mineral assemblage 0.15 0.03 4.55 <d.l. t8a* post-ore carbonates, hydrothermal mineral assemblage 0.30 0.05 10.9 <d.l. t9-5 (4)-2* post-ore carbonates, hydrothermal mineral assemblage 0.53 0.08 13.38 1.1 table 2. chemical composition of carbonates from the trepča pb-zn-ag skarn deposit. <d.l. below detection llimit * major element and ree content adopted from strmić palinkaš et al. (2013) 131 strmić palinkaš et al.: origin and k-ar age of the phreatomagmatic breccia at the trepča pb-zn-ag skarn deposit, kosovo: implications... tained data suggest an enrichment in lree over hree, a week negative cenand a prominent positive eun anomaly (fig. 6). the recrystallized limestone in contact with the skarn mineralization (t6e) is enriched in mno (3.7 wt. %), fe2o3 (0.7 wt. %), y (36.9 ppm), ree (sree = 180.6 ppm), au (1.1 ppb) and mo (0.3 ppm). concentrations of chalcophile elements are mostly within the same ranges as those obtained for the barren recrystallized limestone. exceptions are as and ga that show a slight increase. a decrease in sr concentration positively correlates with a decrease in ca content. the recrystallized limestone in contact with the hydrothermal mineralization (t9-6) is negligibly enriched in mn and fe comparedto the barren recrystallized upper triassic limestone (table 2). syn-ore carbonates (t6a-1, t9-5(4)-1) are significantly enriched in fe (9.5-13.7 wt. % fe2o3), mg (4.5-5.8 wt. % mgo) and mn (5.7-10.3 wt. % mno). large-ion-lithophile elements display low concentrations with the expected exception for sr (104-120 ppm). caesium is slightly increased in syn-ore carbonates associated with the skarn mineral assemblage. in contrast, syn-ore carbonates from the hydrothermal mineral assemblage are enriched in ba (table 2). concentrations of high field strength elements are mostly below their detection limits, with an exception for y and ree that are significantly increased compared to the barren recrystallized upper triassic limestone (table 2). syn-ore carbonates are enriched in chalcophile elements, including ag (up to 0.8 ppm), as (62.9-727 ppm), bi (0.1 ppm), cd (0.3-1.6 ppm), cu (0.4-79.5 ppm), pb (26.3-400 ppm), sb (1.3-7.9 ppm) and zn (49-238 ppm), as well as in au (3.9-16.6 ppb). post-ore carbonates (t6a-2, t7-2, t8a, t9-5(4)-2) are depleted in fe (0.20.9 wt. % fe2o3), mg (0.2-0.3 wt. % mgo), mn (2.4-3.2 wt. % mno) and the majority of chalcophile elements compared to syn-ore carbonates (table 2). however, some post-ore carbonates may have increased concentrations of pb (~600 ppm), zn (~110 ppm) and ag (~1 ppm). 4.2. stable isotope composition of carbonates the δ18o and δ13c data obtained on the 68 carbonates from 34 hand specimens are listed in table 3 and shown in figure 7. the barren limestones have average δ13c and δ18o values of 2.9 ± 1.1 ‰ v-pdb and 21.9 ± 2.5 ‰ v-smow, respectively. the limestones in contact with the breccia together with the limestone fragments from the breccia are shifted toward significantly lower δ18o values. recrystallized limestones in contact with the skarn (δ13c = -4.0 ± 0.1 ‰, δ18o = 14.0 ± 1.5 ‰) and hydrothermal mineralization (δ13c = 0.8 ± 2.8 ‰, δ18o = 18.5 ± 4.2 ‰) differ in both their carbon and oxygen, isotopic composition. syn-ore and post-ore carbonates exhibit depletion in 13c and 18o compared to the barren recrystallized limestone. carbonates separated from the pyroclastic rocks of the caldera display variable δ13c and δ18o composition with values between -10 and -1 ‰ and 15.5 to -21 ‰, respectively. travertine deposits have uniform isotopic composition with average δ13c and δ18o values of -1.2 ± 0.2 ‰ and 20.0 ± 0.3 ‰, respectively. 4.3. fluid inclusion data fluid inclusions have been studied in transparent minerals, calcite and quartz, hosted by different types of breccia fragments and in the recrystallized limestone at its contacts with the breccia (fig. 8). the data are summarized in figure 9. calcite grains selected from the recrystallized limestone at the contact with the main breccia pipe (t3a, 75 m above mean sea level) host fluid inclusions of pseudosecondary and secondary origin. according to their petrographic features, three types of fluid inclusion assemblages have been distinguished: type 1) assemblages composed of two phase, l-rich inclusions (fig. 8a); type 2) assemblages that contain coexisting l-rich and v-rich inclusions (fig. 8b); and type 3) assemblages of two phase, v-rich inclusions (fig. 8c). liquid-rich figure 7. δ13c vs. δ18o plot of various carbonates from the trepča pb-zn-ag skarn deposit. 132 vol. 69/1 fluid inclusion assemblages (type 1) can be subdivided into two subtypes according to their microthermometric data. subtype 1a comprises l-rich inclusions with the degree of fill around 0.7 and homogenization temperatures (th) between 343 and 370°c (fig. 9). they have a eutectic temperature (te) near -50°c suggesting cacl2, nacl and kcl as the principal salts dissolved in the aqueous solution (borisenko, 1977; samson & walker, 2000). the salinity in the range between 19.8 to 20.6 wt.% nacl equ. (fig. 9) is estimated from the final ice melting temperature (tm ice) recorded in the interval between -16.5 and -17.5°c (bodnar, 1993). subtype 1b comprises l-rich inclusions with the degree of fill around 0.8 and th recorded between 275 and 290°c (fig. 9). eutectic temperatureswere recorded around -50°c as well, but salinities in the range between 2.6 and 4.2 wt.% nacl equ. (tm ice = -1.5 to -2.5°c) are significantly lower than the values obtained for the former subtype of l-rich inclusions (fig. 9). fluid inclusion assemblages comprising coexisting l-rich and v-rich inclusions (type 2) suggest an entrapment of boiling fluids (bodnar et al., 1985). liquid-rich inclusions have a variable degree of fill, varying between 0.6 up to 0.8. the te near -50°c was recorded in several fluid inclusions revealing cacl2, nacl and kcl as the principal dissolved salts. whereas this type of fluid inclusion has a salinity greater than 23 wt. % nacl equ., the ice dissolution precedes the hydrohalite dissolution. in some inclusions hydrohalite melts as the final solid phase. the final melting temperature in the interval between -3.2 and 0°c suggests salinities between 25.8 and 26.2 wt.% nacl equ. (fig. 9; sterner et al., 1988). in other inclusions of this type, hydrohalite was transformed into halite at temperatures around 0°c. halite dissolves at temperatures up to 7°c pointing to the maximum salinity of 26.3 wt.% nacl equ. (sterener et al., 1988). total homogenization occurs by vapour phase disappearance in the temperature range between 285 and 305°c (fig. 9). phase transitions in v-rich inclusions have not been recorded. fluid inclusion assemblages that contain only v-rich inclusions (type 3) have been recorded as well but the ambiguous phase transitions preclude their interpretation. the recrystallized limestone at the contact with lateral branches filled with the milled matrix fluidized breccia (t4, t7-4) hosts visible fluid inclusions only in calcite grains very close to the breccia-limestone contact. already at 5 cm from the contact inclusions become too small for reliable measurements (<5 μm). at a distance of 10 cm from the contact fluid inclusions have not been detected. measurable fluid inclusions are l-rich, with the degree of fill around 0.7 to 0.8 (fig. 8d). homogenization into the liquid phase was recorded in the temperature interval from 360 to 375°c (fig. 9). ice melting occurred between -7.4 and -9°c corresponding to the salinity of 11.0 to 12.9 wt.% nacl equ. (fig. 9). the clasts that comprise a magnetite core and a pyrite rim (km7-1, km8) were sampled from the surface (835 m above figure 8. a. pseudosecondary l-rich fluid inclusion assemblages from the recrystallized limestone at the contact with the main breccia pipe; b. pseudosecondary coexisting land v-rich fluid inclusions from the recrystallized limestone at the contact with the main breccia pipe; c. pseudosecondary v-rich fluid inclusion assemblages from the recrystallized limestone at the contact with the main breccia pipe; d. pseudosecondary l-rich fluid inclusion assembla ges from the recrystallized limestone at the contact with the lateral breccia branches; e. pseudose condary l-rich fluid inclusion assemblages from calcite grains in clasts composed of a magnetite core and a pyrite rim; f. boiling effect within calcite grains separated from clasts composed of a magnetite core and a pyrite rim; g. vapour-rich inclusions in calcite grains selected from pyroclastic deposits; h. two-phase aqueous fluid inclusions in calcite grains selected from pyroclastic deposits. 133 strmić palinkaš et al.: origin and k-ar age of the phreatomagmatic breccia at the trepča pb-zn-ag skarn deposit, kosovo: implications... figure 9. correlation of homogenization temperature (th) and salinity for fluid inclusions hosted at contacts of the phreatomagmatic breccia and its host rocks as well as within different types of clasts and pyroclastic rocks. mean sea level). over 80% of the primary and pseudosecondary fluid inclusions within calcite crystals belong to the two-phase, l-rich, type. they vary in size up to 25 mm (fig. 8e). primary fluid inclusion assemblages homogenized into the liquid phase in the interval between 315 and 335°c (fig. 9). the first melting (near-eutectic) temperature around -52 ºc suggests that cacl2, nacl and kcl are the principal dissolved salts (borisenko, 1977; samson & walker, 2000). the tm hyd value recorded in the range between -27.7 and -29.1°c coincides with the nacl/(nacl+cacl2) mass ratio between 34 and 41 %. the tm ice in the range between -2.7 and -4.1°c corresponds to an apparent salinity of4.5 to 6.6 wt.% nacl equ. (fig. 9). locally, the boiling effect is perceived. it is characterized by fluid inclusion assemblages comprising coexisting liquidand vapour-rich fluid inclusions (fig. 8f) with overlapping values of homogenization temperatures between 310 and 325°c (fig. 9). liquid-rich inclusions have relatively high salinities (tm ice = -19.1 to -21.0°c; salinity = 21.7 to 23.1 wt.% nacl equ.; fig. 9). pseudosecondary fluid inclusion assemblages mostly comprise liquid-rich fluid inclusions with homogenization temperatures between 265 and 285°c (fig. 9). their apparent salinity ranges between 2.2 and 4.8 wt.% nacl equ. (fig. 9; tm ice = -1.3 to -2.9°c). in addition, several fluid inclusion assemblages composed of coexisting liquidand vapour-rich inclusions have been recorded. their homogenization temperatures mostly overlap with those obtained for the liquidrich pseudosecondary fluid inclusion assemblages, but they have slightly greater salinities (fig. 9; tm ice = -1.5 to -3.2°c; salinity = 2.6 to 5.1 wt.% nacl equ.). in the deeper part of the breccia, at horizon x (75 m above mean sea level), several different types of fragments were studied. microthermometry on the majority of barren recrystallized limestone fragments (t2) was hampered, due to the presence of only monophase fluid inclusions. in contrast, recrystallized limestone fragments accompanied with fibroradial arsenopyrite and magnetite (t2a) have been eligible for microthermometric studies. pseudosecondary fluid inclusion assemblages are overprinted by secondary fluids. both fluid inclusion generations are characterized by te around -50°c (cacl2-nacl±kcl-h2o system). pseudosecondary fluid inclusions show tm hyd in the range between -27.0 and -28.5°c indicating the nacl/(nacl+cacl2) mass ratio between 37 and 45 %. the majority of fluid inclusions have moderate salinities in the range between 12.9 and 14.0 wt.% nacl equ. (fig. 9; tm ice = -9.0 to -10.0°c) and homogenize into liquid phase in the temperature interval from 330 to 340°c (fig. 9). several inclusions with higher salinity (tm ice = -20.5 to -21.0°c; salinity = 22.8 to 23.1 wt.% nacl equ.) have also been recorded (fig. 9). due todecrepitation before homogenization, usually between 320 and 340°c, only a few total homogenizations into the liquid phase were obtained in the range from 360 to 380°c (fig. 9). secondary inclusions have tm hyd in the interval from -22.1 to -26.0°c (the nacl/ (nacl+cacl2)mass ratio = 52-89 %), tm ice between -2.0 and -4.5°c (salinity = 3.4-7.1 wt.% nacl equ.) and th from 295 to 310°c (fig. 9). quartz separated from the carbonate fragments within the main breccia (t1) was suitable for microthermometric investigations. quartz is represented by euhedral crystals accompanied bydickite aggregates. primary l-rich fluid inclusions homogenize to a liquid phase at temperature between 285 and 320°c (fig. 9). their salinities range from 6.0 to 8.5 wt.% nacl equ. (fig. 9). secondary inclusions have not been observed probably due to their small size. 134 vol. 69/1 sample level type of mineralization description δ13c (‰, vpdb) δ18o (‰, vsmow) barren limestone t6f x host limestone, barren, recrystallized white recrystallized carbonate 1.9 21.5 km-10 surface host limestone, barren, recrystallized greyish calcite crystals 2.8 24.6 sts-0 x host limestone, barren, recrystallized greyish recrystallized carbonate 4 19.6 carbonate from pyroclastic rocks p1-1 surface caldera matrix, grey calcite -10.1 17.1 p1-2 surface caldera white calcite grain -3.7 15.6 p1-3 surface caldera matrix -3.9 16 p2-1 surface caldera matrix -7.2 16.6 p2-2 surface caldera white calcite grain 2.4 21 travertine deposit p4-1 surface travertine deposit grayish to dark purple travertine -1.1 19.6 p4-2 surface travertine deposit grayish to dark purple travertine -1.1 20 p4-3 surface travertine deposit grayish to dark purple travertine -1.2 20.1 p4-4 surface travertine deposit grayish to dark purple travertine -1.6 20.2 carbonate from breccia t2-1 x recrystallized limestone fragment grey massive carbonate -4.3 13.3 t2-2 x recrystallized limestone fragment white massive carbonate -4.4 12.6 t2a-1 x recrystallized limestone fragment with magnetite and arsenopyrite white calcite grain (rhombohedral) -4.5 13.5 carbonate at contact with breccia t3-1 x late phase calcite white calcite crystals (elongated, scalenohedral) 0.4 13.5 t3-2 x recrystallized limestone, barren white massive carbonate -2.8 12.5 t7-4-1 x recrystallized limestone, barren greyish calcite crystals 2.2 17.9 hydrothermal parageneses, pre-ore tr-vii-7 vii recrystallized carbonate grey calcite crystals 2.9 22.8 tr-xi-2-1 xi recrystallized carbonate grey calcite crystals 2.8 22.2 tr-xi-2-2 xi recrystallized carbonate yellowish calcite crystals -3.8 14.2 tr-xi-5-1 xi recrystallized carbonate yellowish calcite crystals 0.9 15.5 tr-xi-6-1 xi recrystallized carbonate white calcite grain (rhombohedral) -2.2 12.9 tr-xi-3-1 xi recrystallized carbonate grey calcite crystals 3 21 t9-5-a-1 x recrystallized carbonate grey calcite grain 2.3 20.9 skarn parageneses, pre-ore t6e x crystallized carbonate white calcite crystals -4.1 15.1 t9-6-1 x massive carbonate yellow-pinkish massive carbonate -3.9 12.9 hydrothermal parageneses, syn-ore trviii-2-1 viii carbonate impregnated with galena white massive carbonate -1.1 9.7 trviii-4-1 viii carbonate impregnated with galena yellow massive carbonate -3.8 15.5 tr-xi-4-2 xi carbonate co-existing with quartz white calcite grain 1.2 11.5 sts-1 x massive carbonate with mineralization yellow-pinkish massive carbonate (light) -3.7 15.4 sts-3 x massive carbonate grey massive carbonate -0.8 18.4 t7-2-2 x calcite cogenetic with sph mineralization white calcite veins 5.6 15 148a-1 x calcite cogenetic with py mineralization white calcite veins 0.9 14 t8-2-2 ix calcite cogenetic with sph mineralization white calcite veins 1.3 10.8 t9-5-4 x carbonate impregnated with sph and py white massive carbonate -3.8 13.2 table 3. carbon and oxygen isotope composition of carbonates from the trepča pb-zn-ag skarn deposit. 135 strmić palinkaš et al.: origin and k-ar age of the phreatomagmatic breccia at the trepča pb-zn-ag skarn deposit, kosovo: implications... sample level type of mineralization description δ13c (‰, vpdb) δ18o (‰, vsmow) skarn parageneses, syn-ore t6-w x white carbonate associated with quartz alteration of hedenbergite white carbonate, fine-grained 0.1 14.1 t6-y x yellow carbonate associated with quartz alteration of hedenbergite yellow carbonate, fine-grained 1.3 15.8 t6-g x grey carbonate associated with quartz alteration of hedenbergite grey carbonate, fine-grained -2.5 11.8 t6a-1 x 1st carbonate after sph mineralization pink -4.6 14.4 t6a-2 x 2nd carbonate after sph mineralization yellow massive carbonate -0.1 11.2 t6a-3 x 3rd carbonate after sph mineralization white massive carbonate 1 14 t6b-1 x 1st carbonate after sph mineralization pink -4 14.1 t6b-2 x 2nd carbonate after sph mineralization yellow massive carbonate -0.2 9.9 t9-1-2 x carbonate in conntact with quartz yellow massive carbonate 0.9 9 t9-3-1 x carbonate in conntact with quartz white massive carbonate 1.3 8.9 t9-4-2 x carbonate cogenetic with py mineralization yellow massive carbonate -1.7 11.2 hydrothermal parageneses, post-ore tr-v-1 v last phase calcite grey calcite crystals (elongated, scalenohedral) 2.3 15.9 trviii-2-2 viii last phase calcite white calcite crystals (elongated, scalenohedral) 0.9 11.7 trviii-4-2 viii last phase calcite white calcite crystals (elongated, scalenohedral) 0.1 12.7 sts-2 x massive carbonate, late phase yellow-pinkish massive carbonate (dark) -3.8 15.4 t5-1 x last phase calcite white calcite crystals (rhombohedral, vertical) 1.8 15.5 t7-2-1 x last phase calcite white calcite crystals (rhombohedral, vertical) 3.2 14.6 t7-2-3 x last phase calcite white calcite crystals (rhombohedral, vertical) 2.3 14.5 t7-3a-1 x last phase calcite white calcite crystals (rhombohedral) 2.1 15.1 t7-5-1 x last phase calcite white calcite crystals (rhombohedral) 0.8 16.1 t8a-1 ix last phase calcite white calcite crystals (rhombohedral) 1.2 15.9 t8-2-1 ix last phase calcite white calcite crystals (rhombohedral) 0.9 16.3 t9-5-1 x last phase calcite (5mm to sph min) white calcite crystals (rhombohedral) 0, 5 10.2 t9-5-2 x last phase calcite (10mm to sph min) white calcite crystals (rhombohedral) 1 13.9 t9-5-a-4 x last phase calcite white calcite crystals (rhombohedral) 1.3 15.7 t9-5-a-5 x phase before the last white calcite crystals (rhombohedral) -2.1 10.9 skarn parageneses, post-ore t6-1 x last phase calcite white calcite crystals (rhombohedral) 0.6 16.7 t9-1-1 x last phase calcite white calcite crystals (rhombohedral, vertical) -0.7 13.1 t9-4-1 x last phase calcite white calcite crystals (rhombohedral, isometric) 3 16.1 t9-4-3 x last phase calcite white calcite crystals (rhombohedral, isometric) -0.2 12.7 t9-6-2 x last phase calcite white calcite crystals (rhombohedral) -0.7 16 t9-6-(4)-1 x last phase calcite white calcite crystals (rhombohedral, vertical) -2.7 14.2 t9-6-(4)-2 x phase before the last white calcite crystals (rhombohedral) 1.6 9.1 two types of fluid inclusions were recognized in calcite grains hosted by pyroclastic material of the caldera (p1, p2): 1) vapour-rich inclusions represent the majority of the inclusion population (fig. 8g). this type of fis are resistant to developing phases during extreme cooling to the temperature of liquid nitrogen and heating up to 400°c, and 2) two-phase aqueous fluid inclusions consist of vapour and liquid water at room temperature (fig. 8h). two-phase inclusions can be subdivided into liquid-rich and vapour-rich subtypes according to their vapour to liquid ratio. coexistence of inclusions table 3. continuated 136 vol. 69/1 with miscellaneous degrees of filling suggests inhomogeneous trapping from boiling fluid (fig. 7). the near-eutectic temperature observed within liquid-rich inclusions around -50°c reflects the cacl2-nacl-±kcl-h2o compositional model. tm ice in the range between -4.2 and -4.6°c corresponds to a salinity of between 6.7 and 7.3 wt.% nacl equ. (fig. 9). homogenizations recorded in the same temperature interval for liquid-rich and vapour-rich inclusions (320340°c; fig. 9) suggest formation under boiling conditions. 4.4. k/ar data k-ar ages obtained on samples from the phreatomagmatic breccia at the trepča pb-zn-ag skarn deposit are reported in table 4. sanidine and whole rock analysis of hydrothermally altered quartz-latite gave two almost concordant ages of 24.0 ± 0.7 and 25.1 ± 0.9 ma, respectively. dating of the milled breccia reveals ages of 20.9 ± 1.7 and 23.2 ± 0.7 ma. the younger age is unreliable due to a low amount of radiogenic ar and a large uncertainty. 5. discussion this paper focuses on the breccia pipe and its role in ore-forming processes at the trepča pb-zn-ag skarn deposit. the p-t-x conditions during breccia emplacement were estimated from descriptive features, mineralogy, stable isotope and fluid inclusion data obtained from the breccia fragments and wall rocks. the trepča deposit was formed during three distinctive stages that are common for all types of skarn deposits elsewhere: (1) the stage of isochemical contact metamorphism during igneous rock emplacement, (2) the prograde stage characterized by metasomatic replacement of carbonate rocks with anhydrous silicate minerals, and (3) the retrograde hydrous stage that resulted in the alteration of earlier-formed mineral assemblages. deposition of ore minerals accompanies stages 2 and 3 (e.g. meinert et al., 2005). 5.1. the stage of isochemical contact metamorphism the isochemical contact metamorphism stage resulted in recrystallization of the country rocks (upper triassic limestone and schist, fig. 2). the size of calcite grains in the recrystallized limestone varies from several millimetres, at places spatially distal to the mineralization and the breccia pipe, up to several centimetres near the contact with the ore bodies and the breccia. the absence of fluid inclusions from the barren recrystallization limestone suggests recrystallization without involvement of either h2o or co2. the barren recrystallized limestone is characterized by a high cao content and ree patterns with the negative cen anomaly that are typical for marine carbonates (elderfield & greaves, 1982; hu et al., 1988). furthermore, the average δ13c value of the barren recrystallized limestone corresponds well to the worldwide phanerozoic marine carbonate values (veizer & hoefs, 1976) and δ18o values are consistent with the triassic marine carbonate values (claypool et al., 1980). obviously, the chemical and isotope composition of the limestone were not significantly disturbed by the recrystallization processes. 5.2. the prograde anhydrous stage the host recrystallized limestone at the contact with the prograde (skarn) mineralization is depleted in 13c and 18o, reflecting the contribution of magmatic co2 (zheng & hoefs, 1993; rosatelli et al., 2010). the increased content of fe, mn, mo, as, au, cs, ga, ree and y suggests that the listed elements were transported by infiltrating magmatic fluids. 5.3. the main breccia limestone contact fluid inclusions are abundant in calcite crystals of the recrystallized limestone near contacts with the main breccia pipe and its lateral branches suggesting that aqueous fluids, channeled by the breccia, were involved in the recrystallization processes. multiple generations of fluid inclusions that have been found at the contact with the main breccia pipe give an insight into the p-t-x characteristics of fluids involved in breccia formation processes. the high-temperature (th=343370°c) and high salinity (19.8-20.6 wt.% nacl equ.) l-rich fluid inclusion assemblages (subtype 1a, fig. 8a) represent the earliest among all recorded fluid inclusion generations. to keep fluids in the liquid phase at temperatures above 343°c the pressure should exceed 18 mpa (fig. 10). the high pressure possibly reflects lithostatic conditions that preceded breccia formation. the travertine deposits found at the trepča deposit surface (approximately 850 m above mean sea level) mark the preserved palaeosurface and allow estimation of the palaeodepth. the analyzed recrystallized limestone-breccia contact (sample t3a, 75 m above mean sea level) occurs around 775 m below the palaeosurface implying the lithostatic pressure of 21 mpa. the pressure correction applied to the representative isochores (fig. 10) suggests the formation temperature between 350 and 370°c. the fluid inclusion assemblages that comprise coexisting l-rich and v-rich inclusions (type 2, fig. 8b) reflect boiling conditions probably related to decompression of the system from a lithostatic to hydrostatic regime due to the brecciation (strmić palinkaš et al., 2014). assuming the fluid salinity around 20 wt. % nacl, the homogenization temperature between 285 and 305°c corresponds to adepth between 600 and 800 m below the former water table (fig. 11). boiling resulted in the separation of high salinity l-rich and low salinity v-rich inclusions. the fluid temperature drop from 350-370°c to 285-305°c suggests an adiabatic process and allows the calculation of the steam loss (e.g., simpson et al., 2015): hl,tf(subtype 1a) = (1-y)×hl,th(l-rich, type 2) + y×hv,th(l-rich, type 2) (1) in this equation, hl,tf(subtype 1a) represents an average specific enthalpy of the fluid before boiling at the temperature estimated from the pressure corrected representative isochores for subtype 1a fluid inclusions (fig. 10), hl,th(l-rich, type 2) and hv,th(l-rich, type 2) are average specific enthalpies of liquid and vapor phases separated during boiling at temperature equal to the homogenization temperature of l-rich inclusions coexisting with v-rich inclusions, and y is the steam (vapour) fraction. the specific enthalpies for liquid and vapour phases (assuming pure h2o) were adopted from keenan et al. (1969). the calculated steam loss ranges around 30%. the fluid inclusion assemblages composed 137 strmić palinkaš et al.: origin and k-ar age of the phreatomagmatic breccia at the trepča pb-zn-ag skarn deposit, kosovo: implications... only of v-rich inclusions (type 3) reveal that fluids periodically were completely converted to vapour, probably due to episodic fluxes of hot magmatic fluids. assuming the palaeodepth of around 775 m, the pressure correction applied to the representative isochores for the moderate-temperature (th=275-290°c) and low salinity (2.6-4.2 wt.% nacl equ.) l-rich fluid inclusion assemblages (subtype 1b, fig. x1) reveals their entrapment temperature between 275 and 290°c. cooling and dilution of the fluids may reflect a contribution of descending groundwaters in the later stages of breccia formation. the recrystallized limestone at the contact with the main breccia pipe (t3a) shows an increase in sio2, fe2o3, and mno content accompanied with the depletion in the cao content comparing to the composition of the barren recrystallized limestone placed distally from the breccia. some trace elements, including pb, as, sb, w, y and ree are also enriched. the ree pattern possesses a weak negative cen anomaly and a prominent positive eunanomaly. furthermore, the recrystallized limestone at the contact with the breccia is depleted in 13c and 18o indicating the contribution of isotopically light co2 (fig. 7) probably of a magmatic origin (zheng & hoefs, 1993; rosatelli et al., 2010). 5.4. lateral breccia branches limestone contact the lateral dyke-like branches infilled with the milled matrix represent non-venting branches of the main phreatomagmatic breccia (corbett & leach, 1998). the hydraulic fracturing of country rocks requires a fluid pressure equal to the minimum principal stress plus the tensile strength of the rocks (jaeger & cook, 1979). the lrich fluid inclusions found in the recrystallized limestone at contacts with the fissures indicate that recrystallization processes occurred in the presence of moderate salinity single phase (liquid) fluids that were channeled through the fissures. the minimum entrapment pressure was around 20 mpa (fig. 10) suggesting that the pressure was controlled by lithostatic conditions. the pressure correction applied to the representative isochores, assuming the lithostatic conditions (fig. 10), suggests the entrapment temperature was between 365 and 375°c. the abundant rock flour that was injected into such a type of fissures reflects transport by fluidization (mccallum, 1985; branquet et al., 1999; clark & james, 2003). the various types of hydrothermal alterations, including sericitization, kaolinitization, pyritization and carbonatization, that affected the rock flour suggest an intensive hydrothermal circulation. the major element composition and the ree content of the recrystallized limestone at this type of contacts (samples t4 and t74, 75 m above mean sea level) overlap with the values obtained for the barren recrystallized limestone placed distally from the breccia. however, some trace elements, including pb, ni, as, cd and sb are more abundant than in the barren limestone suggesting their transport by aqueous fluids. the δ13c values overlap with values recorded for the barren recrystallized limestone revealing the negligible contribution of magmatic co2. in contrast, the decreased δ18o values may be attributed to the involvement of aqueous fluids. according to the fractionation equation for a calcite-water pair (zhang, 1999), the fluid in the isotopic equilibrium with the analyzed calcite (δ18o=17.9‰) at temperatures around 370°c should have and 18o value of +13.7‰. figure 10. pressure-temperature diagram showing the ranges of isochores for l-rich fluid inclusions hosted within the recrystallized limestone at its contact with the main breccia pipe (sample t3a, 75 m above mean sea level) and its contact with the lateral breccia branches (sample t4, 75 m above mean sea level). the boiling conditions obtained from the fluid inclusion assemblage composed of coexisting l-rich and v-rich inclusions are plotted too (type 2, sample t3a, 75 m above mean sea level). the liquid-vapour curve for h2o-nacl fluids with 5, 10 and 20 wt % nacl is adopted from bodnar & vityk (1994). table 4. the k/ar data obtained at the trepča pb-zn-ag skarn deposit. sample sample description dated fraction k % 40ar* cm3/g 40ar* % k/ar age (ma) tr-6 surface, hydrothermaly altered quartz-latite sanidine 8.54 8.035×10-6 86.7 24.0 ± 0.7 whole rock 2.77 2.787×10-6 55.1 25.1 ± 0.9 t7-4a level x., milled breccia whole rock 2.43 1.985×10-6 16.7 20.9 ± 1.7 t4a level x., milled breccia whole rock 8.01 7.277×10-6 82.7 23.2 ± 0.7 138 vol. 69/1 5.5. the main breccia clasts the clasts of country rocks and skarn mineralization that preceded the breccia formation underwent intense milling, mixing and hydrothermal alterations depending on their lithological characteristics and spatial position within the breccia. they show mutual differences in shape, dimension, composition, alteration, direction and distance of transport typical for phreatomagmatic breccias (e.g. sillitoe, 1985; baker et al., 1986; tamas & milesi, 2002). sericitization of the breccia matrix, locally accompanied by minor kaolinitization, indicate increased water activity under near-neutral to weakly acidic conditions. the fragments composed of a magnetite core and a pyrite rim (samples km7-1, km8; 835 m above mean sea level) suggest an increase in oxygen and sulfur fugacities over time (fig. 12). textural features suggest that the fibroradial magnetite core, accompanied by a mixture of quartz and carbonates, was formed by retrograde alteration of hedenbergite under increased oxygen fugacity: 3 cafe2+si2o6 + 3 co2 + ½ o2 → fe2+fe3+ 2o4 + 3 caco3 + 6 sio2 (2) hedenbergite magnetite calcite quartz the fo2 vs. fs2 diagram constructed for the pre-breccia stage (lithostatic regime; p ≈ 20 mpa; t ≈ 400°c) and the main stage of the breccia formation (hydrostatic regime; p ≈ 7.5 mpa; t ≈ 300°c) reveals that hedenbergite stability strongly depends on temperature and pressure, favouring the prograde stage conditions (fig. 12). the increased water activity and oxygen fugacity as well as the decreased temperature are direct consequences of the breccia pipe formation that enhanced the permeability along the recrystallized limestone-schist contact and enabled incursions of cold oxygenated groundwater in the system. the presence of bi-sulfides speaks in favour of the skarn precursor for these types of fragments. namely, according to fluid inclusion data published by strmić palinkaš et al. (2013), the prograde skarn mineralization was formed at temperatures between 390 and 475°c. in contrast, the main ore deposition stage appears to have been largely contemporaneous with the retrograde stage of skarn development at temperatures below 350°c. in weakly acidic to near-neutral aqueous solutions bi is predominantly transported as the bi(oh)3 0 complex (skirrow & walshe, 2002) and its mobility is negligible at temperatures below 400°c (tooth et al., 2013). the pyrite rim reflects sulfidation of magnetite into pyrite under the increased sulfur fugacity: fe2+fe3+ 2o4+ 3 s2 + 8 h+ → 3 fes2 + 4 h2o (3) magnetite pyrite the isotope composition of sulfides from the trepča pb-znag skarn deposit suggest a magmatic origin of sulfur (strmić palinkaš et al., 2013). the solubility of sulfur in silicate magma is a function of temperature, pressure, feo and sio2 content and oxygen fugacity (carroll & webster, 1994; o’neill & mavrogenes, 2002; de moor et al., 2013). under reducing conditions, the sulfur solubility decreases with decreasing temperature, and cooling of magma plays an important role in sulfur degassing. furthermore, at the trepča pb-znag skarn deposit, phreatomagmatic explosions and formation of diatreme unsealed the system, decreased the pressure and additionally favouring sulfur release. p-t-x characteristics of fluids involved in retrograde alteration processes are evidenced by multiple generations of fluid inclusions. primary liquid-rich fluid inclusion assemblages in calcite grains entrap moderate salinity high temperature fluids. a significant increase in salinity recorded by the coexisting primary liquidand vapour-rich inclusions may have been caused by boiling within an open system (e.g. simmons & browne, 1997; baumgartner, 2008) and may not represent a fluid that originally had higher salinities. alternatively, as reported by simmons (1991) and albinson et al. (2001) at the fresnillo pb-zn-ag deposit, zacatecas, mexico, the variation in salinity may have been caused by discrete pulses of saline fluids. the presence of numerous vapour-rich inclusions favours a boiling scenario that would also be consistent with the observed salinity variations without temperature change. assuming hydrostatic conditions, boiling occurred at depths between 600 and 800 m (fig. 11). the pseudosecondary liquid-rich fluid in clusion assemblages suggest dilution and cooling over time. sporadic boiling episodes increased the salinity up to 0.3 wt.% nacl (from 2.2-4.8 wt.% nacl equ. up to 2.6-5.1 wt.% nacl equ.) suggesting steam loss of between 6 and 15%. the decreased δ13c and δ18o values obtained for calcite grains suggest an involvement of magmatic co2 (table 3, fig. 7). similar δ13c and δ18o values have been recorded for the recrystallized limestone fragments as well as for the recrystallized limestone that hosts the skarn mineralization (table 3, fig. 7). the fragments composed of pyrite, pyrrhotite and minor bisulfides reflect that locally increases in sulfur fugacity were sufficient to complete sulfidation of hedenbergite to pyrrhotite and/ or pyrite. bismuth, a trace element in the skarn paragenesis, behaves in an immobile manner during the retrograde alteration processes accumulating in forms of various bi-sulfides. figure 11. fluid inclusion homogenization temperatures for coexistent liquid-rich and vapour-rich inclusions fitted on the boiling pointdepth curves for fluids of different salinities (after haas, 1971) estimate the formation depths assuming the hydrostatic regime. 139 strmić palinkaš et al.: origin and k-ar age of the phreatomagmatic breccia at the trepča pb-zn-ag skarn deposit, kosovo: implications... the limestone fragments found in the deeper portion of the breccia pipe are commonly replaced by siderite and occasionally impregnated by pyrite and microcrystalline quartz. dickite aggregates and euhedral quartz occupy cavities. the fluid inclusion data obtained from quartz suggest a formation temperature of between 290 and 330ºc, from a fluid with salinity in the range of 6-8.5 wt% nacl equ. and a ph below 5.5 (strmić palinkaš et al., 2009). the δ34s value of pyrite suggests a magmatic source of sulfur (strmić palinkaš, 2009). two distinctive generations of fluid inclusions in recrystallized limestone fragments accompanied with fibroradial arsenopyrite and magnetite suggest the dilution and cooling of hydrothermal fluids over time. the δ13c and δ18o values overlap with data obtained for calcite hosted by fragments composed of a magnetite core and pyrite rim, the recrystallized limestone fragments and the recrystallized limestone that hosts the skarn mineralization (table 3, fig. 7). 5.6. hydrothermal carbonates the recrystallized limestone that hosts the hydrothermal mineralization shows a weak contribution of magmatic co2 and slight enrichment in mn and fe. concentration of other elements overlap with values obtained for the barren recrystallized upper triassic limestone. syn-ore and post-ore carbonates associated with both skarn and hydrothermal parageneses point to the diminishing influence of magmatic co2 during the main-ore and post-ore stages (table 3, fig. 7). syn-ore carbonates are enriched in fe, mg, mn, many chalcophile elements, including ag, as, bi, cd, cu, pb, sb and zn, as well as in au, y and ree. post-ore carbonates are depleted in fe, mg, mn and the majority of chalcophile elements comparing to syn-ore carbonates, reflecting declining hydrothermal activity. traveritine, with traces of carbonates enriched in zn and grains of galena, barite and gypsum, was precipitated during the late stage of hydrothermal activity. according to pentecost (2005), travertines are chemically-precipitated continental limestones where precipitation is mainly driven by co2 degassing from a groundwater source leading to calcium carbonate supersaturation. based on the origin of the co2 interacting with the groundwater pentecost (2005) subdivided travertines into meteogene and thermogene deposits. soil-zone and atmospheric co2 may be characterized as meteoric in origin, since the terrestrial vegetation and associated soil contains carbon fixed from the atmosphere. travertines formed from groundwaters charged with a meteoric carrier are termed meteogene whereas thermogene travertines are formed as a massive deposit from fluids carrying co2 originating from thermal processes. waters related to meteogene travertines have a lower temperature (gene rally ambient), a lower dissolved inorganic carbon content (dic < 10 mmol/l), a lower co2 partial pressure (pco2< 0.01 mpa) and ph values between 7 and 8. furthermore, while meteogene travertines generally display a negative carbon isotope composition (δ13c between -12 and 0‰), thermogene travertines, in contrast, show δ13c values in the range of -1 to 10‰ (pentecost, 2005). on the basis of the geochemical characteristics the trepča travertine should have been considered as thermogene in its origin although a contribution of organic-derived carbon cannot be excluded. particularly, signs of rapid co2 degassing during deposition such as bubbles and radial calcite crystals are typical ofthermogene travertine. the δ13c data mostly overlap with δ13c values previously published for thermogene travertines with a magmatic origin of co2 (e.g. pentecost, 2005; d’alessandro et al., 2007). in addition, dissolution of the host recrystallized limestone during the main ore stage enriched hydrothermal fluids on hco3 -. furthermore, decreased δ13c values reflect the influence of organic carbon (e.g. lazareva et al., 2008). the δ18o value is predominantly affected by a significant contribution of circulating groundwaters at elevated temperatures. 5.7. pyroclastic deposits according to their isotope composition, calcite grains hosted by pyroclastic material of the caldera represent minute fragments of the recrystallized triassic limestone. in contrast, the carbonate matrix is significantly depleted in 13c reflecting the contribution of organic carbon. textural characteristics of pyroclastic material with fossil imprints of leaves and plant roots evidence precipitation within a lacustrine environment enriched in organic matter remains. however, a contribution of magmatic co2 should not be ignored. fluid inclusions hosted by calcite grains suggest their formation under boiling conditions. homogenization temperatures between 320 and 340°c for fluid inclusions with salinities around 7 wt.% nacl equ. indicate the formation depth of approximately 500 650 m and 1300 1750 m assuming lithostatic and hydrostatic conditions (fig. 11), respectively. younger v-rich inclusions reflect a sudden pressure drop probably related to phreatomagmatic explosions. 5.8. the k/ar age the presence of the hydrothermally altered quartz-latite dyke within the main breccia core and overlapping k/ar ages of hydrothermally altered quartz-latite (24.0 ± 0.7 ma and 25.1 ± 0.9 ma) and the milled matix breccia (23.2 ± 0.7 ma) suggest that magmatic activity coincided with the mineralizing events. the volcanic rocks in the area, produced by the late oligocene postfigure 12. log f o2 vs. log f s2 diagram of the ca-fe-si-s-oh system constructed for the pre-breccia stage (lithostatic regime; p ≈ 20 mpa; t ≈ 400°c) and the main stage of the breccia formation (hydrostatic regime; p ≈ 7.5 mpa; t ≈ 300°c). the x(co2) value is set at 0.05. 140 vol. 69/1 collisional magmatic activity (cvetković et al., 2004), display mostly overlapping k/ar (this study) and ar/ar ages (borojević šoštarić et al., 2012). 6. conclusions according to the mineralogical, geochemical and isotope data we can distinguish several stages that directed formation of the phreatomagmatic breccia pipe at the trepča pb-zn-ag skarn deposit: 1) the stage of isochemical contact metamorphism resul ted from emplacement of a magmatic chamber during the late oligocene postcollisional magmatic activity. this stage preceded the mineralization and the breccia formation and resulted in the recrystallization of country rocks without significant changes in their chemical and isotope composition. 2) the stage of prograde (skarn) mineralization preceded the breccia formation. the prograde (skarn) mineralization resulted from the interaction of magmatic fluids with the recrystallized upper triassic limestone. the magmatic fluids were derived from a cooling magmatic body below the ore deposit. the host recrystallized limestone at the contact with the prograde (skarn) mineralization has an increased fe, mn, mo, as, au, cs, ga, ree and y content suggesting their transport by infiltrating magmatic fluids. the decreased δ13c and δ18o values reflect the contribution of magmatic co2. in addition, the pyroxene predominant mineralogy reflects a low oxygen fugacity and a low water activity. 3) emplacement of the quartz-latite dyke along the contact between the recrystallized limestone and the overlying schist. an interaction of the hot magmatic body with cold ground water resulted in phreatomagmatic explosions and formation of the phreatomagmatic breccia. the pyroclastic deposits found at the surface of the trepča pb-zn-ag skarn deposit confirm subaqueous explosive volcanic activity. the contact between the main breccia pipe and the host recrystallized limestone has preserved geochemical and isotope evidence of variable p-t-x conditions during the phreatomagmatic brecciation. the early generations of fluid inclusions precede the brecciation and reflect the recrystallization under lithostatic conditions at temperatures between 350 and 370°c. the phreatomagmatic brecciation turned the system from the lithostatic to hydrostatic regime, decreasing the pressure and triggering the fluid boiling. assuming an adiabatic process, the temperature drop from 350-370°c to 285-305°c resulted with a steam loss of approximately 30%. the later generations of fluid inclusions point to cooling and dilution of the fluids due to an enhanced contribution of descending groundwaters in late stages of the breccia formation. the host recrystallized limestone at the contact with the main breccia pipe is enriched in si, fe, mn, pb, as, sb, w, ree and y and depleted in 13c and 18o. the lateral dyke-like branches infilled with the milled matrix represent non-venting branches of the main phreatomagmatic breccia. the fluid inclusions founded in the recrystallized limestone at contacts with the fissures indicate that hot (365-375°c) and moderate salinity single phase aqueous (liquid) fluids enriched in pb, ni, as, cd and sb were channeled through the fissures under lithostatic conditions. 4) the hydrothermally altered quartz-latite dyke points to an increase in water activity over time. partly preserved sanidine accompanied with the mixture of muscovite and quartz reflects a near-neutral to weakly acidic environment. 5) the clasts of country rocks and skarn mineralization underwent intense milling and mixing due to repeated magmatic penetrations. sericitization of the breccia matrix, locally accompanied with minor kaolinitization, point to an increased water activity under near-neutral to weakly acidic conditions. large fragments originally composed of anhydrous skarn minerals (pyroxenes) are usually completely altered to a mixture of fibroradial magnetite, quartz and various amount of carbonates suggesting an increase in oxygen fugacity. their py rite rims reflect that the increase in the oxygen fugacity was fo llowed by an increase in sulfur fugacity. the fragments predominantly composed of fe-sulfides and minor bi-sulfides indicate that locally increases in sulfur fugacity were sufficient to complete sulfidation of hedenbergite to pyrrhotite and/or pyrite. the increase in water activity and oxygen fugacity are associated with the breccia pipe formation that enhanced the permeability along the recrystallized limestone-schist contact and enabled groundwater incursions in the system. at the same time, cooling and decompression of the system intensified the magmatic sulfur degassing. 7) syn-ore and post-ore carbonates associated with both skarn and hydrothermal parageneses reflect the diminishing influence of magmatic co2 during the main-ore and post-ore stages. syn-ore carbonates are enriched in fe, mg, mn, many chalcophile elements, including ag, as, bi, cd, cu, pb, sb and zn, as well as in au, y and ree. in contrast, post-ore carbonates reflect a declining hydrothermal activity and the depletion in fe, mg, mn and the majority of chalcophile elements. 8) travertine deposits were precipitated in the late stage of hydrothermal activity at the trepča pb-zn-ag skarn deposit. their isotope signature suggests that carbon originates predominantly from the dissolute host recrystallized limestone influenced by significant amounts of magmatic and organic carbon. in contrast, δ18o values are strongly affected by the contribution of circulating groundwaters at elevated temperatures. although the phreatomagmatic breccia at the trepča pbzn-ag skarn deposit does not carry significant amounts of the ore mineralization, its formation was crucial for ore deposition. phreatomagmatic explosions and formation of the breccia triggered the retrograde stage increasing the water activity and oxygen fugacity in the system. in addition, cooling and decompression of the system contributed to more effective degassing of magmatic sulfur increasing the sulfur fugacity. acknowledgement this study was supported by the croatian ministry of sciences, technology and sports (projects 119-0982709-1175). we are grateful to the geological teams of the trepča deposit, in particular to m. diehl for help and constructive discussions during fieldwork. we would especially like to thank reviewers, vasilios melfos and irina marinova, whose comments improved the paper. 141 strmić palinkaš et al.: origin and k-ar age of the phreatomagmatic breccia at the trepča pb-zn-ag skarn deposit, kosovo: implications... references albinson, t., norman, d.i., cole, d. & chomiak, b. (2001): controls on formation of low-sulfidation epithermal deposits in mexico: constraints from fluid inclusion and stable isotope data.– society of economic geologist special publication, 8, 1–32. anderson, e.d., atkinson jr, w.w., marsh, t. & iriondo, a. (2009): geology and geochemistry of the mammoth breccia pipe, copper creek mining district, southeastern arizona: evidence for a magmatic–hydrothermal origin.– miner. deposita, 44/2, 151–170. doi: 10.1007/ s00126-008-0206-2 baker, e.m., kirwin, d.j. & taylor, r.g. (1986): hydrothermal breccia pipes.– egru contribution 12, james cook university of north queensland, australia, 45p. baker, e.m. & andrew, a.s. (1991): geologic, fluid inclusion and stable isotope studies of the gold-bearing breccia pipe at kidston, queensland, australia.– econ. geol., 86/4, 810-830. doi: 10.2113/gsecongeo.86.4.810 balogh, k. (1985): k/ar dating of neogene volcanic activity in hungary: experimental technique, experiences and methods of chronological studies.– atomki report, debrecen, d/1, 277–288. baumgartner, r., fontboté, l. & vennemann, t. (2008): mineral zoning and geochemistry of epithermal polymetallic zn-pb-ag-cu-bi mineralization at cerro de pasco, peru.− econ. geol., 103/3, 493-537. doi: 10.2113/gsecongeo.103.3.493 bodnar, r.j. (2003): introduction to fluid inclusions.− min assoc can short course series, 32, 1–8. bodnar, r.j. & vityk, m.o. (1994): interpretation of microthermometric data for h2o-nacl fluid inclusions.– in: de vivo, b. & frezzotti, m.l. (eds.): fluid inclusions in minerals: methods and applications. short course of the working group (ima) inclusions in minerals, virginia polytechnic institute and state university, blacksburg, virginia, 117–130. bodnar, r.j., reynolds, t.j. & kuehn, c.a. (1985): fluid inclusion systematics in epithermal systems.– rev. econ. geol., 2, 73–98. borisenko, a.s. (1977): study of the salt composition of solutions of gas– liquid inclusions in minerals by the cryometric method.– geol.geofiz., 18, 16–27. borojević šoštarić, s., cvetković, v., neubauer, f., palinkaš, l.a., bernroider, m. & genser, j. (2012) oligocene shoshonitic rocks of the rogoznamts.(central balkan peninsula): evidence of petrogenetic links to the formation of pb–zn–ag ore deposits.– lithos, 148/1, 176–195. borojević šoštarić, s., palinkaš, l.a., neubauer, f., hurai, v., cvetković, v., roller-lutz, z., mandić, m. & genser, j. (2013): silver-base metal epithermal vein and listwanite hosted deposit crnac, rogozna mts., kosovo, part ii: a link between magmatic rocks and epithermal mineralization.– ore geol. rev., 50/1, 98–117. borojević šoštarić, s., palinkaš, a.l., neubauer, f., cvetković, v., bernroider, m. & genser, j. (2014): the origin and age of the metamorphic sole from the rogozna mts., western vardar belt: new evidence for the one-ocean model for the balkan ophiolites.– lithos, 192/1, 39–55. branquet, y., cheilletz, a., giuliani, g., laumonier, b. & blanco, o. (1999): fluidized hydrothermal breccia in dilatant faults during thrusting: the colombian emerald deposits.– geological society, london, special publications, 155, 183–195. doi: 10.1144/gsl. sp.1999.155.01.14 byrne, k. & tosdal, r.m. (2014): genesis of the late triassic southwest zone breccia-hosted alkalic porphyry cu-au deposit, galore creek, british columbia, canada.– econ. geol., 109/4, 915-938. doi: 10.2113/econgeo.109.4.915 canet, c., gonzález-partida, e., camprubí, a., castro-mora, j., romero, f.m., prol-ledesma, r.m., linares, c., romero-guadarrama, j.a. & sánchez-vargas, l.i. (2011): the zn–pb–ag skarns of zacatepec, northeastern oaxaca, mexico: a study of mineral assemblages and ore-forming fluids.– ore geol. rev., 39/4, 277–290. cannell, j., cooke, d.r., walshe, j.l. & stein, h. (2005): geology, mineralization, alteration, and structural evolution of the el teniente porphyry cu-mo deposit.– econ. geol., 100/5, 979-1003. doi: 10.2113/gsecongeo.100.5.979 carroll, m.r. & webster, j.d. (1994): solubilities of sulfur, noble gases, nitrogen, chlorine, and fluorine in magmas.– rev. miner. geochem., 30, 231–279. clark, c. & james, p. (2003): hydrothermal brecciation due to fluid pressure fluctuations: examples from the olary domain, south australia.– tectonophysics, 366/3, 187–206. doi: 10.1016/s0040-1951(03)00095-7 claypool, g.e., holser, w.t., kaplan, i.r., sakai, h. & zak, i. (1980): the age curves of sulfur and oxygen isotopes in marine sulfate, and their mutual interpretation.– chem geol, 28/1, 199–259. doi: 10.1016/0009-2541(80)90047-9 cooke, d.r. & bloom, m.s. (1990): epithermal and subjacent porphyry mineralization, acupan, baguio district, philippines: a fluid-inclusion and paragenetic study.– j. geochem.explor., 35/1, 297–340. doi: 10.1016/0375-6742(90)90042-9 corbett, g.j. & leach, t.m. (1998): southwest pacific rim gold-copper systems: structure, alteration, and mineralization.– society of economic geologists special publication, 6, 234. cvetković, v., karamata, s. & knežević, v. (1995): volcanic rocks of the kopaonik district.– geology and metallogeny of the kopaonik mt. symposium, belgrade, 185–194. cvetković, v., prelević, d., downes, h., jovanović, m., vaselli, o. & pecskay, z. (2004): origin and geodynamic significance of tertiary postcollisional basaltic magmatism in serbia (central balkan peninsula).– lithos, 73/3–4, 161−186. doi: 10.1016/j.lithos.2003.12.004 d’alessandro, w., giammanco, s., bellomo, s. & parello, f. (2007): geochemistry and mineralogy of travertine deposits of the sw flank of mt. etna (italy): relationships with past volcanic and degassing activity.– j. volcanol. geoth. res., 165/1-2, 64-70. doi: 10.1016/j.jvolgeores.2007.04.011 davies, a.g., cooke, d.r., gemmell, j.b. & simpson, k.a. (2008): diatreme breccias at the kelian gold mine, kalimantan, indonesia: precursors to epithermal gold mineralization.– econ. geol., 103/4, 689-716. doi: 10.2113/gsecongeo.103.4.689 de moor, j.m., fischer, t.p., sharp, z.d., king, p.l., wilke, m., botcharnikov, r.e., cottrell, e., zelenski, m., marty, b., klimm, k., rivard, c., ayalew, d., ramirez, c. & kelley, k.a. (2013): sulfur degassing at erta ale (ethiopia) and masaya (nicaragua) volcanoes: implications for degassing processes and oxygen fugacities of basaltic systems.– geochem. geophy. geosy., 14/10, 4076-4108. doi: 10.1002/ggge.20255 dilek, y., furnes, h. & shallo, m. (2007): suprasubduction zone ophiolite formation along the periphery of mesozoic gondwana.– gondwana res., 11/4, 453–475. doi: 10.1016/j.gr.2007.01.005 dimitrijević, m.d. (2001): the dinarides and the vardar zone: a short review of the geology.– acta vulcanol., 13/1, 1–8. elderfield, h. & greaves, m.j. (1982): the rare earth elements in seawater.– nature 296, 214–219. doi: 10.1038/296214a0 féraud, j., maliqi, g. & meha, v. (2007): famous mineral localities: the trepca mine, stari trg, kosovo.– mineral. rec., 38/4, 267-298. goldstein, r.h. (2001): fluid inclusions in sedimentary and diagenetic systems.– lithos, 55/1, 159–193. doi: 10.1016/s0024-4937(00)00044-x goldstein, r.h. & reynolds, t.j. (1994): systematics of fluid inclusions in diagenetic minerals.– society for sedimentary geology, short course, 31, 199 p. doi: 10.2110/scn.94.31 haas, j.l. (1971): the effect of salinity on the maximum thermal gradient of a hydrothermal system at hydrostatic pressure.– econ. geol., 66/6, 940– 946. doi: 10.2113/gsecongeo.66.6.940 henley, r.w. (1984): chemical structure of geothermal systems.– rev. econ. geol., 1, 73–98. hu, x., wang, y.l. & schmitt, r.a. (1988): geochemistry of sediments on the rio grande rise and the redox evolution of the south atlantic ocean.– geochim. cosmochim. acta, 52, 201–207. doi: 10.1016/00167037(88)90068-3 jaeger, j.c. & cook, n.g.w. (1979): fundamentals of rock mechanics.– chapman and hall, london, 593 p. janković, s. (1997): the carpatho-balkanides and adjacent area: a sector of the tethyan eurasian metallogenic belt.– miner. deposita, 32/5, 426–433. karamata, s., majer, v. & pamić, j. (1980): ophiolites of yugoslavia.– ofioliti, 1/1, 105–125. karamata, s., olujić, j., protić, lj., milovanović, d., vujnović, l., popević, a., memović, e., radovanović, z. & resimić-šarić, k.(2000): the western belt of the vardar zone the remnant of a marginal sea.– in: karamata, s. & janković, s. (eds.): geology and metallogeny of the dinarides and the vardar zone: zvornik, academy of science and arts of republika srpska, 131–135. keenan, j.h., keyes, f.g., hill, p.g. & moore, j.g. (1969): steam tables.– john wiley, new york, 1962 p. kołodziejczyk, j., pršek, j., melfos, v., voudouris, p.c., maliqi, f. & kozub-budzyń, g. (2015): bismuth minerals from the stanterg deposit (trepça, kosovo).– neues jb. miner. abh., 192/3, 317-333. landtwing, m.r., dillenbeck, e.d., leake, m.h. & heinrich, c.a. (2002): evolution of the breccia-hosted porphyry cu-mo-au deposit at agua rica, argentina: progressive unroofing of a magmatic hydrothermal system.– econ. geol., 97/6, 1273-1292. doi: 10.2113/gsecongeo.97.6.1273 lazareva, e.v., bryanskaya, a.v., zhmodik, s.m., ponomarchuk, v.a., barkhutova, d.d. & semionova, d.v. (2008): carbon isotope composition in microbial mats and travertine of brz.– geochim.cosmochim.acta, 72/12, a521. 142 vol. 69/1 lorenz, v. (1973): on the formation of maars.– bull.volcanol., 37/2, 183–204. doi: 10.1007/bf02597130 malo, m., moritz, r., dube, b., chagnon, a., roy, f. & pelchat, c. (2000): base metal skarns and au occurrences in the southern gaspé appalachians: distal products of a faulted and displaced magmatic-hydrothermal system along the grand pabos-restigouche fault system.– econ. geol., 95/6, 1297–1318. mccallum, m.e. (1985): experimental evidence for fluidization processes in breccia pipe formation.– econ. geol., 80/6, 1523-1543. doi: 10.2113/ gsecongeo.80.6.1523 meinert, l.d. (1992): skarns and skarn deposits.– geosci. can., 19/4, 145–162. meinert, l.d., dipple, g.m. & nicolescu, s. (2005): world skarn deposits.– econ. geol. 100th anniversary volume, 299–336. milovanović, d., marchig, v. & karamata, s. (1995): petrology of the crossite schist from fruška gora mts. (yugoslavia), relic of a subducted slab of the tethyan oceanic crust.– j. geodyn., 20/3, 289–304. nance, w.b. & taylor, s.r. (1976): rare earth element patterns and crustal evolution: i. australian post-archean rocks.– geochim. cosmochim. acta, 40/12, 1539−1551. doi: 10.1016/0016-7037(76)90093-4 pentecost, a. (2005): travertine.– springer-verlag, berlin heidelberg, 445 p. robertson, a.h., trivić, b., đerić, n. & bucur, i.i. (2013): tectonic development of the vardar ocean and its margins: evidence from the republic of macedonia and greek macedonia.– tectonophysics, 595/1, 25–54. doi: 10.1016/j.tecto.2012.07.022 rosatelli, g., wall, f., stoppa, f. & brilli, m. (2010): geochemical distinctions between igneous carbonate, calcite cements, and limestone xenoliths (polino carbonatite, italy): spatially resolved laicpms analyses.– contrib. mineral. petr., 160/5, 645-661. doi: 10.1007/s00410-0100499-x samson, i.m. & walker, r.t. (2000): cryogenic raman spectroscopic studies in the system nacl–cacl2–h2o and implications for low-temperature phase behaviour in aqueous fluid inclusions.– can. mineral., 38/1, 35–43. schumacher, f. (1950): die lagerstätte der trepča und ihre umgebung. izdavačko preduzeće saveta za energetiku i ekstraktivnu industriju vlade fnrj, beograd, 65 p. schumacher, f. (1954): the ore deposits of yugoslavia and the development of its mining industry.– econ. geol., 49/5, 451–492. sharp, i.r. & robertson, a.h. (2006): tectonic-sedimentary evolution of the western margin of the mesozoic vardar ocean: evidence from the pelagonian and almopias zones, northern greece.– geological society, london, special publications, 260/1, 373–412. doi: 10.1144/gsl. sp.2006.260.01.16 sillitoe, r.h. (1985): ore-related breccias in volcanoplutonic arcs.– econ. geol., 80/6, 1467–1514. doi: 10.2113/gsecongeo.80.6.1467 sillitoe, r.h., baker, e.m. & brook, w.a. (1984): gold deposits and hydrothermal eruption breccias associated with a maar volcano at wau, papua new guinea.– econ. geol., 79/4, 638-655. doi: 10.2113/gsecongeo.79.4.638 simmons, s.f. (1991): hydrologic implications of alteration and fluid inclusion studies in the fresnillo district, mexico: evidence for a brine reservoir and a descending water table during the formation of hydrothermal ag-pb-zn orebodies.– econ. geol., 86/8, 1579–1601. doi: 10.2113/gsecongeo.86.8.1579 simmons, s.f. & browne, p.r.l. (1997): saline fluid inclusions in sphalerite from the broadlands-ohaaki geothermal system: a coincidental trapping of fluids being boiled toward dryness.– econ. geol., 92/4, 485–489. doi: 10.2113/gsecongeo.92.4.485 simpson m.p., strmić palinkaš s., mauk j.l., bodnar r.j. (2015): fluid inclusion chemistry of adularia-sericite epithermal au-ag deposits of the southern hauraki goldfield, new zealand.– econ. geol., 110/3, 763–786. skewes, m.a., holmgren, c. & stern, c.r. (2003): the donoso copper-rich, tourmaline-bearing breccia pipe in central chile: petrologic, fluid inclusion and stable isotope evidence for an origin from magmatic fluids.– miner. deposita, 38/1, 2–21. doi: 10.1007/s00126-002-0264-9 skirrow, r.g. & walshe, j.l. (2002): reduced and oxidized au-cu-bi iron oxide deposits of the tennant creek inlier, australia: an integrated geologic and chemical model.– econ. geol., 97/6, 1167-1202. doi: 10.2113/gsecongeo.97.6.1167 sterner, s.m., hall, d.l. & bodnar, r.j. (1988): synthetic fluid inclusions. v. solubility relations in the system nacl-kcl-h2o under vapor-saturated conditions.– geochim. cosmochim. acta, 52/5, 989–1005. doi: 10.1016/0016-7037(88)90254-2 strmić palinkaš, s. (2009): genesis of hydrothermal and skarn paragenesis in the pb-zn-ag mineral deposit trepča (staritrg), kosovo.– unpublished phd thesis, university of zagreb, zagreb, 143 p. strmić palinkaš, s., palinkaš, l.a., molnar, f. & diehl, m. (2007): basic research in service of successful exploitation in pb-zn-ag stari trg mine, trepča, kosovo.– in: andrew, c.j. (ed.): digging deeper: navan, ireland, irish association for economic geology, 165–167. strmić palinkaš, s., borojević šoštarić, s., bermanec, v., palinkaš, l., prochaska, w., furić, k. & smajlović, j. (2009): dickite and kaolinite in the pb-zn-ag sulphide deposits of northern kosovo (trepča and crnac).– clay miner., 44/1, 67–79. strmić palinkaš, s., palinkaš, l.a., renac, c., spangenberg, j.e., lüders, v., molnar, f. & maliqi, g. (2013): metallogenic model of the trepča pb-zn-ag skarn deposit, kosovo: evidence from fluid inclusions, rare earth elements, and stable isotope data.– econ. geol., 108/1, 135–162. strmić palinkaš, s., wegner, r., čobić, a., palinkaš, l.a., de brito barreto, s., váczi, t. & bermanec, v. (2014): the role of magmatic and hydrothermal processes in the evolution of be-bearing pegmatites: evidence from beryl and its breakdown products.– am. mineral., 99/2-3, 424–432. sudar, m. (1986):mikrofosili i biostratigrafija trijasaunutrašnjih dinarida između gučeva i ljubišnje (triassic microfossils and biostratigraphy of the inner dinarides between gučevo and ljubišnja mts., yugoslavia; in serbian with english summary).– geol. an. balk.poluos., 50, 151–394. sudar, m. & kovacs, s. (2006): metamorphosed and ductilely deformed conodonts from triassic limestones situated beneath ophiolite complexes: kopaonik mountain (serbia) and bükk mountains (ne hungary)-a preliminary comparison.– geol.carpath., 57/3, 157−176. tamas, c.g. & milesi, j.-p. (2002): hydrovolcanic breccia pipe structures-general features and genetic criteria. i. phreatomagmatic breccias.– studia ubb geologia, 47/1, 127–147. terzić, s.b., sommerauer, j. &harnik, a.b. (1974): macroscopic cosalite crystals from the pb-zn ore deposit trepča (yugoslavia).– schweiz. mineral. petrogr. mitt., 54/1, 209–211. tooth, b., etschmann, b., pokrovski, g.s., testemale, d., hazemann, j.-l., grundler, p.v. & brugger, j. (2013): bismuth speciation in hydrothermal fluids: an x-ray absorption spectroscopy and solubility study.– geochim. cosmochim. acta, 101/1, 156–172. doi: 10.1016/j.gca.2012.10.020 tornos, f., casquet, c., galindo, c., velasco, f. & canales, a. (2001): a new style of ni-cu mineralization related to magmatic breccia pipes in a transpressional magmatic arc, aguablanca, spain.– miner. deposita, 36/7, 700–706. doi: 10.1007/s001260100204 trumbull, r.b., slack, j.f., krienitz, m.s., belkin, h.e. & wiedenbeck, m. (2011): fluid sources and metallogenesis in the blackbird co–cu–au–bi–y–ree district, idaho, usa: insights from major-element and boron isotopic compositions of tourmaline.– can. mineral., 49/1, 225-244. vasković, n. & matović, v. (2010): ophiolites of the vardar zone and the dinarides: central and west serbia.– ima 2010 field trip guide rs1. department of mineralogy, geochemistry and petrology, university of szeged, 55 p. veizer, j.d. & hoefs, j. (1976): the nature of 18o/16o and 13c/12c secular trends in sedimentary carbonate rocks.– geochim. cosmochim. acta, 40/11, 1387–1395. veselinovic-williams, m. (2011): characteristics and origin of polymetallic mineralisation in the kopaonik region of serbia and kosovo, with particular reference to the belo brdo pb-zn (ag) deposit.– unpublished phd thesis, kingston university, london, 150 p. vry, v.h., wilkinson, j.j., seguel, j. & millán, j. (2010): multistage intrusion, brecciation, and veining at el teniente, chile: evolution of a nested porphyry system.– econ. geol., 105/1, 119–153. doi: 10.2113/ gsecongeo.105.1.119 wallier s, rey r, kouzmanov k, pettke t, heinrich ca, leary s, o’connor g, tămaş cg, vennemann t, ullrich t (2006): magmatic fluids in the breccia-hosted epithermal au-ag deposit of roşia montană, romania.– econ. geol., 101/5, 923–954. yang, k.& bodnar, r.j. (1994): why is economic porphyry copper mineralization absent from the granitoids of the gyeongsang basin, south korea? evidence from silicate melt and aqueous fluid inclusions.– int. geol. rev., 36/7, 608–628. zelić, m., agostini, s., marroni, m., pandolfi, l. & tonarini, s. (2010): geological and geochemical features of the kopaonik intrusive complex (vardar zone, serbia).– ofioliti, 35/1, 33–47. zheng, y.f. (1999): oxygen isotope fractionation in carbonate and sulfate minerals.– geochem. j., 33, 109–126. doi: 10.2343/geochemj.33.109 zheng, y.f. & hoefs, j. (1993): carbon and oxygen isotopic covariations in hydrothermal calcites.– miner. deposita, 28/2, 79–89. doi: 10.1007/ bf00196332 les algues dasycladales du permien et du trias nouvelle tentative d’inventaire bibliographique, géographique et stratigraphique bruno r.c. granier 1 and tonêi grgasovi∆ 2 g eol. croat. 53/1 1 197 27 figs. 1 tab. zagreb 2000 key words: algae, dasycladales, permian, triassic, synonymy list, bibliography. mots-clés: algues, dasycladales, permien, trias, liste synonymique, bibliographie. 1 adresse actuelle: pdd/zakum, adma-opco, p.o.box303, abu dhabi, unitedarab emirates (bgranier@adma.co.ae); adresse permanente: le clair côteau, 14-a rue de la guaize, 28130 maintenon, france. 2 institute of geology, sachsova 2, p.o.box 268, hr-10000 zagreb, croatia. abstract the present work enlists as comprehensively as possible the permian and triassic dasyclad algae. for each species, localities and stratigraphic positions attached to the quoted specimens are detailed within the synonymy list. résumé la présente étude tente de dresser un inventaire exhaustif des algues dasycladales du permien et du trias. à la liste bibliographique de chaque espèce viennent s’adjoindre l’indication de la localité et de la position stratigraphique des spécimens référencés. 1. introduction cette étude constitue une extension de la publication de granier & deloffre (1995), troisième volet d’un “inventaire critique des algues dasycladales fossiles” consacré aux formes du permien et du trias. les diverses espèces d’algues dasycladales alors décrites y étaient énumérées; les principaux problèmes nomenclaturaux y étaient évoqués et pour certains résolus; enfin, la répartition stratigraphique des formes valides y était esquissée. il s’agissait là d’une étude préliminaire faisant partie d’un projet plus ambitieux, le projet petralga (“permian and triassic algae”), dont le but est d’établir une synthèse portant sur l’ensemble des algues du permien et du trias (granier, 1993). il fallait aller au-delà de ce document: pour ce faire, nous nous sommes livrés à un examen rigoureux de l’ensemble des données disponibles. nous nous sommes appuyés sur les deux “essais d’inventaires” publiés par emberger, il y a une vingtaine d’années déjà, le premier sur les algues du carbonifère et du permien (emberger, 1976) et le second sur celles du trias (emberger, 1979). toutefois, à la différence de leur auteur, nous n’avons pas voulu retenir les citations non accompagnées d’une figuration (et donc non vérifiables), sauf si ces citations concernaient un problème nomenclatural. ce sont ainsi plus de 600 publications (dont plus de la moitié non référencées par notre honorable prédécesseur) qui ont été analysées. nous avons porté une attention particulière aux points suivants: citation exacte des références bibliographiques, validité des taxons, identification du 1. introduction................................................ revue historique teintée de statistiques.............. nouvelles remarques taxonomiques................... distributions géographique et stratigraphique.... conclusion.......................................................... 2. liste synonymique.................................... 3. bibliographie............................................... permian and triassic dasyclad algae: bibliographic, geographic, and stratigraphic reappraisal.................................... table des matières 1 2 3 5 6 7 164 195 2 geologia croatica 53/1 matériel-type, distributions stratigraphiques et géographiques précises avec une utilisation d’appelations standardisées tout au long de la liste synonymique, ainsi que les éventuelles divergences entre le corps du texte et les légendes des illustrations. dans de nombreux cas, nous avons également pondéré la validité de certaines déterminations dans la liste synonymique: une interrogation “?” correspond à une attribution incertaine et une négation “non” à une erreur de détermination. revue historique teintée de statistiques l’analyse des données réunies à l’occasion de cette publication nous permet de souligner quelques aspects sous-jacents concernant notamment l’évolution de la recherche sur les dasycladales du permien et du trias. la figure 1 présente sous la forme d’un graphique un bilan de cette recherche depuis ses origines, au xixème siècle, jusqu’à nos jours. trois étapes principales ont été identifiées: − la première période correspond à une étape de “balbutiements”, avec les premières publications sur les dasycladales triasiques dès les années 1850 et celles sur les dasycladales permiennes à partir des années 1900 seulement. cette étape s’est poursuivie pendant la première moitié du xixème siècle. parmi les premiers paléontologues à étudier les dasycladales du permien et du trias, notons une prédominance “géographique” des auteurs germanophones ou italophones avec notamment schafhäutl (18531867), schauroth (1855-1859), stoppani (1857-1865), gümbel (1872-1874), benecke (1876-1898), salomon (1895), schubert (1907-1909), ou encore karpinsky (1909a, b). à cette première étape, est rattaché le nom de julius von pia (1912-1943), indubitablement le spécialiste le plus renommé pour ses travaux sur les algues fossiles, en général, et sur les formes de cet intervalle stratigraphique, en particulier; − la seconde période correspond à une étape d’expansion et d’internationalisation, postérieure à la deuxième guerre mondiale, qui a largement bénéficié des jalons posés par julius von pia. parmi cette nouvelle génération de chercheurs, nous relevons, entre autres, les noms de johnson (1942-1969), herak (1950-1967), kordé (1950-1965), endo (19511969), konishi (1952-1959), kochansky-devidé (1955-1984), elliott (1956-1982), kulik (1956-1978), bystrický (1957-1986), horiguchi (1957-1961), panti∆ (1959-1997), milanovi∆ (1962-1986), flügel (1963-1999), ott (1963-1975), soka» (1964-1998), et güvenç (1965-1979); − la troisième période, qui débute vers le milieu des années 70, correspond à une étape où le nombre de publication reste élevé (bien que décroissant), mais dont la caractéristique principale est surtout une décroissance drastique du nombre de création de nouveaux taxons. concommitamment, le renouvellement des chercheurs est faible; parmi ces derniers, nous retiendrons les noms de zorn (1971-1978), mamet (1973-1996), chuvashov (1974-1993), mu xi-nan (1974-1984), vachard (1974-1997), roux (1975-1989), senowbari-daryan fig. 1 évolution de la recherche sur les dasycladales du permien et du trias de l’origine à l’aube du nouveau millénaire. ce diagramme a été établi à partir des publications référencées dans notre liste bibliographique: le nombre de publications (représenté par des colonnes) ainsi que le nombre d’espèces nouvelles (représenté par des points et des lignes) sont reportés en ordonnées et les décennies sur l’axe des abcisses. seules les nouvelles espèces valides (y compris les synonymes) et celles qui sont susceptibles d’être validées ultérieurement (voir le texte) ont été répertoriées. fig. 1 development of the research on permian and triassic dasycladales. the source are papers cited in the bibliography.the numbers on the vertical axis present the number of papers (columns) and a number of a new species (points and lines) in a decade. only valid new species (synonyms included), and those that can be easily validated (see the text) are included. 3granier & grgasoviê: les algues dasycladales du permien et du trias... (1978-1993), de castro (1979-1997), et di stefano (1981-1991), entre autres. il y a probablement deux causes principales pour justifier cette tendance. on peut considérer que les espèces les plus communes du permien et du trias ont déjà été découvertes; pour cette raison, les publications récentes ne font que recenser les occurrences ou apporter quelques informations complémentaires sur la morphologie. d’autre part, le fort développement de disciplines en partie concurrentes, telles que la “sédimentologie” ou la “stratigraphie séquentielle”, a relégué la micropaléontologie au second plan; les algues n’y sont utilisées que très occasionellement, comme indicateur de faciès par exemple. enfin, accessoirement, il semblerait que parmi les phycologistes les séries du permien et du trias aient perdu en popularité dans les dernières décennies et ce au bénéfice des séries plus jeunes; − si maintenant nous considérons l’avenir de la recherche sur les dasycladales du permien et du trias, il est plutôt sombre et incertain: à terme, le nombre de création d’espèces nouvelles doit tendre vers zéro! nous espérons que de nouveaux chercheurs vont venir à notre discipline et que nos collègues et nous-même poursuivrons notre effort afin d’interrompre cette “dégrinolade” et entrer dans une “période florissante” à l’occasion du nouveau millénaire. au permien, 39 genres valides sont présents, si on rajoute 6 nomina nuda (homonymes ou fondés sur une espèce-type pour laquelle le type n’a pas été clairement identifié “syntypes”), c’est-à-dire 6 genres qui pourraient aisément être validés, celà ferait un total de 45 genres permiens, parmi lesquels 21 (47%) sont monospécifiques. au trias, 20 genres valides sont présents, parmi lesquels 4 (20%) sont monospécifiques. il faut aussi mentionner que 6 genres valides (4 au permien, 2 au trias) sont considérés comme des synonymes juniors. les genres permiens regroupent 155 espèces valides ainsi que 58 susceptibles de l’être (formes rapportées par erreur à un genre non valide, formes pour lesquelles le type n’a pas été clairement identifié, et homonymes). les genres triasiques regroupent 93 espèces valides ainsi que 7 susceptibles de l’être. il y a enfin 32 espèces (8 au permien, 24 au trias) qui sont considérées comme des synonymes juniors. au niveau des variétés, il y en existe 2 seulement pour le permien alors qu’il y en a 23 pour le trias; de plus, la plupart sont regroupées dans les genres oligoporella et physoporella . il est aussi intéressant de relever que les 9 genres qui ont des représentants à la fois au permien et au trias regroupent quelques 144 espèces, c’est-à-dire 46% du nombre total des espèces présentes sur l’ensemble de l’intervalle. toutefois aucune de ces espèces n’a passé la limite permien-trias. de plus, à ce jour, aucune algue n’a été découverte dans les couches du trias inférieur (barattolo, 1991; flügel, 1991; berger & kaever, 1992; granier & deloffre, 1994; bucur, 1999). l’analyse des données bibliographiques permet d’esquisser plusieurs hypothèses de travail concernant l’évolution de ce groupe d’algues. ainsi, par exemple, on remarque que le nombre d’espèces par intervalle temps est bien plus élevé pour le permien qu’il ne l’est pour le trias; par contre le nombre d’espèces par genre est beaucoup plus faible. quelques statistiques complémentaires suggèrent toutefois de considérer avec prudence ces conclusions. en effet, parmi les 213 espèces permiennes valides ou susceptibles d’être validées, 111 d’entre elles (52%) ont été décrites dans une seule localité (82 dans le permien du japon et de la thaïlande); parmi les 100 espèces triasiques, 30 d’entre elles (30%) ont été également décrites dans une seule localité. en outre, quelques différences ont été relevées entre les auteurs dans l’application des critères taxonomiques ainsi que dans leur façon d’interpréter des différences morphologiques entre différents spécimens d’algues. par exemple, un auteur a 17 publications référencées dans notre liste alors qu’il n’a décrit qu’une seule espèce; à l’opposé, un autre auteur a décrit 18 espèces nouvelles dans une seule publication. il existe encore de bien nombreux exemples. toujours dans le but de comprendre l’évolution de ce groupe d’algues, il est également nécessaire de vérifier si l’établissement de nouveaux taxons se justifiait d’un point de vue taxonomique ou si on n’est pas en présence de possible synonymes; c’est l’une des tâches que s’est fixé le projet petralga. nouvelles remarques taxonomiques à l’instar de granier & deloffre (1995), nous désirions reporter les informations taxonomiques, notamment en ce qui concerne les types, seuls éléments auxquels les noms d’espèce sont attachés de manière permanente. nous avons également étendu cette information aux paratypes et si possible à la localisation du matériel. en ce qui concerne les synonymies, nous nous sommes basés sur les listes proposées par pia pour la plupart des références antérieures à 1912. en effet, il est souvent délicat de se forger une opinion à partir de la plupart des publications anciennes: ces dernières comportent des descriptions incomplètes, souvent basées sur des détails anodins, accompagnées de figurations souvent schématiques ou de qualité médiocre, rendant difficile l’utilisation à des fins de taxonomie des formes qui y sont décrites ou figurées. de plus, nombre de collections de la fin du xixéme ou du début du xxème siècles sont soit considérées comme définitivement perdues, soit temporairement (?) inaccessibles. ainsi, dès 1912, pia n’avait pu accéder à la collection de gümbel. le cas le plus évident est illustré par l’exemple de gyroporella ampleforata gümbel 1874: cette espèce n’est connue que par une description succincte de son auteur et ce n’est que très tardivement que pia (1912) 4 geologia croatica 53/1 5granier & grgasoviê: les algues dasycladales du permien et du trias... en a donné les premières figurations. nous sommes donc amenés à nous interroger sur l’identité de ces formes que près de 40 ans de paléontologie séparent et, dans le doute, peut-être serait-il plus opportun de dénommer cette espèce gyroporella ampleforata gümbel ex pia 1912. ensuite, il existait une série d’incertitudes quant aux concepts de genre, d’espèce, de sous-espèce ou de variété dans le groupe des diplopora annulata et “consorts”. le tableau 1 illustre ici l’évolution de ces acceptions de pia (1912, puis 1920) à güvenç (1979), en passant par herak (1957). à la faveur de cette nouvelle synthèse, nous confirmons que d i p l o p o r a s e p t e m t r i o n a l i s (pia 1920) güvenç 1979 doit être considéré comme un nomen nudum car il fait double emploi avec diplopora annulata ( s c h a f h ä u t l , 1853) 1863. le tableau 1 montre également que pia (1920) avait choisi de modifier le statut de deux espèces de sa création, diplopora debilis (gümbel 1872) pia 1912 et kantia dolomitica pia 1912, en celui de variétés de l’espèce diplopora annulata ( s c h a f h ä u t l , 1853) 1863. pour la variété-type, il introduisit le nouveau nom diplopora annulata var. s e p t e m t r i o n a l i s, qui est un nomen nudum puisque le nom de tout taxon infraspécifique qui inclut le type de l’espèce laquelle il est rattaché doit répéter l’epithète spécifique (autonymie, art. 26.1. cibn). ce fait a été précédemment relevé par bystrický (1964) qui, tout en retenant une division de cette espèce en trois variétés, a corrigé le nom de diplopora annulata var. septemtrion a l i s en d. annulata var. a n n u l a t a . au sein de chacune des trois variétés mentionnées, pia (1920) distinguait 2 morphotypes sur la base de la morphologie des rameaux (pores): une “forma trichophora” et une “forma vesiculifera”. pour sa part, herak (1957) concluait que les différences morphologiques relevées au niveau des rameaux constituent le caractère le plus constant et par là-même le plus évident; en lieu et place des formes, il choisit d’établir deux sous-espèces et de renoncer aux variétés. en accord avec cibn, il dénomma diplopora annulata subsp. a n n u l a t a la sous-espèce qui inclut le type de l’espèce à laquelle elle est rattachée. enfin, dans sa révision des dasycladales métaspondyles, güvenç (1979) considéra que les différentes morphologies de rameaux devaient constituer le principal critère de différenciation des genres d i p l o p o r a et k a n t i a. notons cependant que, dans la liste des espèce du genre d i p l o p o r a , il mentionne à la fois diplopora annulata et diplopora septemtrionalis ( à l’évidence, cette dernière a été élevée du statut de variété à celui d’espèce); il s’agit là cependant d’une erreur flagrante puisque ces deux noms recouvrent la même définition et, qui plus est, si le premier nom est valide, le second quand à lui ne l’est pas. l’objet de cette étude n’étant pas de réaliser des modifications nomenclaturales majeures (nouvelles combinaisons, etc.), nous préférons reléguer cette tâche à une étape ultérieure du projet petralga. par conséquent quelques anomalies ont perduré dans la liste synonymique, notamment en ce qui concerne l’attribution générique de quelques espèces. par exemple, plusieurs espèces présentant un arrangement métaspondyle des rameaux ne figurent pas dans la révision de güvenç (1979), il s’agit de: kantia monregalensis baretti 1919, diplopora proba pia 1935, d i p l o p o ra permica kordé 1965, diplopora cellulata h u rka 1967 nom. nud., diplopora borzai b y s t r i c ký 1978, etc., et par conséquent ont probablement une attribution générique inexacte. d’autres auteurs qui ont créé de nouveaux genres ont tout simplement négligé d’y inclure les espèces précédemment établies (en dehors de l’espèce-type) et qui répondent aux critères diagnostiques du genre, c’est par exemple le cas des genres anisoporella botteron 1962 et e u t e u t l o porella de castro 1993. distributions géographique et stratigraphique nous avons suivi l’un des grands principes des “essais d’inventaires” d’emberger, à savoir que les localités et positions stratigraphiques sont indiquées permettant ainsi de mieux cerner distribution géographique et extension stratigraphique de ces algues. dans certains cas, il a été nécessaire de réactualiser les noms et appartenances géopolitiques des localités: par exemple, pontafel et neumarktl, autrichiennes du temps de gümbel, s’appellent aujourd’hui respectivement pontebba et træië, la première est située dans la province du friuli-venezia giulia en italie et la seconde en slovénie. plusieurs types de subdivision se sont succédés ou coexistent pour le permien, en fonction des provinces faunistiques (fusulinidés) ou encore selon les auteurs. nous avons retenu une division tripartite du système: permien inférieur (étages assélien, sakmarien, yahtashien et bolorien en téthys / assélien, sakmarien, artinskien et kungurien en oural), permien moyen (étages kubergandien, murghabien et midien en téthys / ufimien et kazanien en oural), permien supérieur (étages djulfien et dorashamien en téthys / tatarien en oural). les acceptions variant tableau 1 modifications successives des acceptions au sein du groupe informel constitué par diplopora annulata et par les formes affines. le tableau comporte deux parties qui correspondent à deux représentations différentes d’une même histoire. (*) nombre de sections rapportées au taxon illustrées dans la publication. table 1 changes in acceptance within the diplopora annulata group. two parts of the table are two ways to illustrate the nomenclatural changes. (*) number of specimens reffered to the taxa which are figured in the paper. 6 geologia croatica 53/1 avec les auteurs, les qualificatifs des sous-systèmes pourront être indiqués entre guillemets: par exemple, le permien “supérieur” des etats-unis d’amérique, qui correspond probablement dans la plupart des cas au seul guadalupien, est susceptible de représenter des niveaux du permien moyen au permien supérieur basal. le trias, par contre, est classiquement subdivisé en trois sous-systèmes: trias inférieur (étage scythien), trias moyen (étages anisien et ladinien), trias supérieur (étages carnien, norien et rhétien). conclusion en dehors du fait que notre contribution constituera probablement un ouvrage de référence, pratique et d’accès aisé, peut-être incontournable lorsqu’il s’agira de retrouver des articles “rares” ou dits “introuvables” (articles anciens, articles issus de publications “exotiques”, etc.), nous espérons surtout qu’elle va favoriser un regain d’intêret pour l’étude de ces algues, des problèmes liés à leur taxonomie, de leur extension stratigraphique, de leur distribution géographique ou encore de leur évolution. nous souhaitons également que ce travail soit utile non seulement aux chercheurs s’intéressant aux dasycladales fossiles, mais également à tout autre chercheur (paléontologue, sédimentologue, stratigraphe, etc.) travaillant sur les séries du permien et/ou celles du trias. ce travail est la “première pierre” d’un édifice actuellement en cours de construction sur un site internet à accès libre (référence: http://www.angelfire.com/ fl3/alga2000/). nous proposons d’y développer un catalogue du type de celui réalisé par bassoullet et al. (1978) pour les “algues dasycladales du jurassique et du crétacé”, comportant toutes les informations disponibles sur ces formes: éléments diagnostiques (éventuellement révisions), photographies des types, distributions géographique et stratigraphique, etc. afin de disposer d’un outil performant pour leur identification et leur utilisation biostratigraphique ou paléo-environnementale. remerciements nous ne saurions terminer cette introduction sans adresser nos plus sincères remerciements à ceux, nombreux, qui nous ont encouragé et qui ont facilité la réalisation de cet inventaire. nous citerons plus particulièrement: j.c. b r a g a (univ. grenade, espagne), i.i. b u c u r (univ. cluj-napoca, roumanie), r. d e l o ff r e (pau, france), b. ferré (saint étienne du rouvray, france), p. génot (univ. nantes, france), t. h o f m a n n (geologische bundesanstalt, vienne, autriche), z. kotański (panstwowy instytut geologiczny, varsovie, pologne), m.-a. lançon (univ. paris vi, france), j.-p. m a s s e (elf, pau, france), feu m. milanovi∆ (zagreb, croatie), b. soka» (institute of geology, zagreb, croatie), d. vachard (univ. villeneuve d’ascq, france), et nos autres collègues du groupe petralga. nous sommes reconnaissants à i. veli∆, directeur de geologia croatica, pour nous avoir fourni l’opportunité d’éditer cette volumineuse contribution, ainsi qu’à i. vlahovi∆, son rédacteur en chef, pour le soin apporté à la mise en forme et à l’édition finale de ce travail. 7granier & grgasoviê: les algues dasycladales du permien et du trias... 2. liste synonymique acicularia archiac 1843 acicularia boniae iannace, radoi»i∆ et zamparelli 1998 1998 acicularia boniae n. sp.iannace, radoiëiê & zamparelli, pl. 12, fig. 1-5; pl. 13, fig. 1-4 & 5 pars.la calvia, sw cozzo del pellegrino, n s. donato di ninea, e verbicaro, calabria (italie): trias moyen, ? ladinien (piano del minatore fm) .holotype: pl. 12, fig. 1, lame mince n° sd 359/1; isotypes: pl. 12, fig. 2 & pl. 13, fig. 4, lame mince n° sd 359/1; pl. 12, fig. 3-5 & pl. 13, fig. 3 & 5 pars, lame mince n° sd 359/2; pl. 13, fig. 2, lame mince n° sd 359/3, dipartimento di scienze della terra, università di napoli “federico ii” (italie) aciculella pia 1930, non in hirmer 1927 *aciculella bacillum pia 1930, emend. bystricky´ 1975 aciculella bacillum var . bacillum bystrický 1975 1927 (nom. nud.) aciculella bacillum n. gen. n. sp.pia in hirmer, p. 86, non figurée 1930 aciculella bacillum n. gen. n. sp.pia, pl. 4, fig. 7-9.vagluha, ivanovec mts (slovaquie): ladinien ( c h o ë d o l o m i t ).types: pl. 4, fig. 7 & 9, lame mince n° ung i.11 (mfi.11); pl. 4, fig. 8, lame mince n° ung i.11 (a), collection j. von pia, naturhistorisches museum, wien (autriche) 1961a aciculella bacillum.endo, pl. 7, fig. 6, extrait de pia (1930: pl. 4, fig. 7-9) 1974 aciculella bacillum.gaździcki & kowalski, pl. i, fig. 1-8.zaja̧czków, w kielce, holy cross mts. / gory swietokryskie (pologne): anisien, pelsonien (l⁄ ukowa beds) 1975 a c i c u l e l l a b a c i l l u m var. b a c i l l u m n. var.bystrický, pl. iii, fig. 1-3.(slovaquie): ladinien (wettersteinkalk à diplopora annulata ); pl. iii, fig. 4-5.(slovaquie): ladinien (wettersteinkalk à teutloporella h e r c u l e a).typification de l’espèce; lectotype: pl. 4, fig. 8, lame mince n° ung i.11 (a), collection j. von pia, naturhistorisches museum, wien (autriche) 1975 (?) a c i c u l e l l a cf. b a c i l l u m.bystrický, pl. iii, fig. 13-14.(slovaquie): anisien (zone à paraceratites trino dosus) 1975 aciculella bacilum [sic].gaździcki et al., pl. 11, fig. 9.góraz°dz°e, sse opole, haute silésie (pologne): anisien, pelsonien (góraz°dz°e beds) 1975 (?) a c i c u l a r i a sp.pantiê-prodanoviê, pl. xxx, fig. 1.brajovica-ponikvica, nw monténégro (yougoslavie): anisien; pl. xlii, fig. 1-2.©ljivovica, tara mt, w serbie (yougoslavie): ladinien 1980 aciculella bacillum.dragastan, pl. vii, fig. 11.glimeia, pǎdurea craiului, apuseni mts, bihor (roumanie): ladinien 1986 aciculella bacillum.kotański, pl. cv, fig. 26, extrait de gaździcki & kowalski (1974: pl. i, fig. 1); pl. cv, fig. 27, extrait de gaździcki & kowalski (1974: pl. i, fig. 6) 1988 holosporella .deloffre, pl. 4, fig. 8, extrait de pia (1930: pl. 4, fig. 9) 1988 (?) aciculella cf. bacillum.vachard in fontaine & suteethorn, pl. 19, fig. 5.ban chake, kanchanaburi, w krung thep / bangkok (thaïlande): trias supérieur 1993 (?) aciculella cf. a c i c u l e l l a b a c i l l i c u m [s i c].senowbari-daryan et al., pl. 60, fig. 15.flatschkofel, e s. vigilio di marebbe / st. vigil, s valdáora / olang, trentino alto adige (italie): anisien 1994 aciculella bacillum.bucur et al., pl. 12, fig. 13; pl. 13, fig. 2.sasca zone, caraş-severin (roumanie): anisien, pelsonien-illyrien inférieur (sasca fm, valea susara limestone member) 1995 aciculella bacillum.pantiê-prodanoviê, pl. vi, fig. 1-3.podravno, w srebrenica (bosnie-herzégovine): ladinien * l’espèce-type. 8 geologia croatica 53/1 aciculella bacillum var . perforata bystrický 1975 1975 a c i c u l e l l a b a c i l l u m var. p e r f o r a t a n. var.bystrický, pl. iii, fig. 6-9.brnava, muráňska planina (slovaquie): ladinien (wettersteinkalk à teutloporella herculea ).holotype: pl. iii, fig. 6, lame mince n° 1541, collection j. bystricky´, geological institute, slovak academy of sciences, bratislava (slovaquie) 1995 aciculella bacillum var. perforata .iannace, boni & zamparelli, fig. 13.a pars.cozzo del pellegrino, e verbicaro, calabria (italie): ladinien (“calcari” fm) aciculella lemoinei gaździcki et kowalski 1975, nom. nud. 1 9 7 5 (nom. nud.) aciculella lemoinei n. sp.gaździcki & kowalski, p. 12, non figurée.w carpathes (pologne): norien-rhétien.type non figuré aciculella nikleri bystrický 1975 1975 aciculella nikleri n. sp.bystrický, pl. ii, fig. 1-3.carrière dolka, n stratená, n dobπiná, stratenská hornatina mts (slovaquie): norien (furmaneckalk).holotype: pl. ii, fig. 1, lame mince n° 4135, col lection j. bystricky´, geological institute, slovak academy of sciences, bratislava (slovaquie) aciculella ogilvie-gordonae elliott 1971 [synonyme postérieur de aciculella preromangica (praturlon 1963) ott 1974, d’après ott, 1974 ] aciculella pantici bystrický 1975 1975 aciculella pantici n. sp.bystrický, pl. iii, fig. 10-12.n sadok, murá ňska planina (slovaquie): ladinien (wettersteinkalk à diplopora annulata ).holotype: pl. iii, fig. 10, lame mince n° ? 633, collection j. bystrický , geological institute, slovak academy of sciences, bratislava (slovaquie) aciculella preromangica (praturlon 1963) ott 1974 [= macroporella preromangica praturlon 1963 ] 1963 macroporella preromangica n. sp.praturlon, pl. iii, fig. 1-8.preromang, val badia / gadertal, trentino alto adige (italie): permien supérieur (bellerophon fm / “b e l l e r o p h o n-zone” / partie terminale). holotype: pl. iii, fig. 3, lame mince n° f53, collection a. praturlon, micropalaeontological collec tion, institute of geology and palaeontology, roma (italie) 1967 macroporella preromangica .accordi & broglio loriga, pl. xv, fig. 2, extrait de praturlon (1963: pl. iii, fig. 3) 1971 aciculella ogilvie-gordonae n. sp.elliott, pl. 118, fig. 1; pl. 119, fig. 1-2 & 5.plesch d’inaz, val gardena / grödnertal, trentino alto adige (italie): permien supérieur (bellerophon limestone).holotype: pl. 118, fig. 1, lame mince n° v.53904; paratypes: pl. 119, fig. 1, lame mince n° v.53903; pl. 119, fig. 5, lame mince n° v.53905, collection g.f. elliott, british museum (natural history), lon don (royaume-uni) 1974 aciculella preromangica n. comb.ott, p. 45, non figurée 1986 (?) aciculella ogilvie-gordone [sic].mirkoviê, pl. xii, fig. 4.dugo brdo, monténégro (yougoslavie): permien supérieur (bellerophon limestone) 1987 macroporella preromangica .noé, pl. 29, fig. 4.oberkovel, nw ampezzo, friuli venezia giulia (italie): permien supérieur (bellerophon fm / partie supérieure) 1988 macroporella preromangica .broglio loriga et al., pl. 3, fig. 2.sass de pútia / peitler kofel, val badia / gadertal, trentino alto adige (italie): permien supérieur (bellerophon fm) 1988 aciculella ogilvie-gordonae.deloffre, pl. 4, fig. 15, extrait de elliott (1971: pl. 119, fig. 1) 1996 macroporella preromangica .pantiê-prodanoviê, pl. i, fig. 7-11.gaj, vlaπiê mt, oseëina, w krupanj, serbie (yougoslavie): permien supérieur aciculella sokaci bystrický 1975 1975 aciculella sokaci n. sp.bystrický, pl. i, fig. 1-11.carrière dolka, n stratená, n dobπiná, stratenská hornatina mts (slovaquie): norien (furmaneckalk).holotype: pl. i, fig. 1, lame mince n° 4280, collection j. bystricky´, geological institute, slovak academy of sciences, bratislava (slovaquie) 9granier & grgasoviê: les algues dasycladales du permien et du trias... 1975 (?) aciculella cf. sokaci n. sp.bystrický, pl. ii, fig. 8.malý vrch, pleπivecká planina, slovenský kras (slovaquie): carnien, ? julien (tisoveckalk) aciculella spiculiformis bystrický 1975 1964 a c i c u l a r i a sp.bystrický, pl. xxxi, fig. 6.w slavec, ne pleπivec, slovenský kras (slovaquie): carnien, cordevolien (wettersteinkalk) 1975 aciculella spiculiformis n. sp.bystrický, pl. ii, fig. 9-10.ostré vrπky, pleπivecká planina, slovenský kras (slovaquie): carnien, ? julien (tisoveckalk); pl. ii, fig. 7, extrait de bystrický (1964: pl. xxxi, fig. 6); pl. ii, fig. 11.s malý vrch, pleπivecká planina, slovenský kras (slovaquie): carnien (tisoveckalk).holotype: pl. ii, fig. 9, lame mince n° 2841, collection j. bystricky ´, geological institute, slovak academy of sciences, bratislava (slovaquie) aciculopora gaździcki et kowalski 1975, nom. nud. *aciculopora misiki gaździcki et kowalski 1975, nom. nud. 1 9 7 5 (nom. nud.) aciculopora misiki n. gen. n. sp.gaździcki & kowalski, p. 12, non figurée.w carpathes (pologne): norien-rhétien.type non figuré albertaporella johnson 1966, nom. nud. albertaporella anatoliana (güvenç 1970) 1979, nom. nud. [cf. diplopora anatoliana güvenç 1970 ] amicus maslov 1956 amicus japonicus nakamura 1981 , nom. nud. 1981 (nom. nud.) amicus japonicus n. sp.nakamura, pl. 4, fig. 1-10; pl. 5, fig. 8.ishiyama, o _ no-chō tanigumimura, gifu-ken, honshū (japon): permien (ishiyama limestone).syntype (s): pl. 4, fig. 1-2 & 7-10, lames minces n° nsm-pp 6901-1, 6901-5, 6938-1, 6938-2, 6938-7, 6938-8 & 6938-9, national science museum, tokyo (japon) amicus konishii nakamura 1981, nom. nud. 1 9 8 1 (nom. nud.) amicus konishii n. sp.nakamura, pl. 5, fig. 1-7.ishiyama, o _ n o c hō tanigumi-mura, gifuken, honshū (japon): permien (ishiyama limestone).syntype (s): pl. 5, fig. 1-7, lames minces n° nsm-pp 6901-1, 6901-2, 6901-3, 6901-4 & 6938-11, national science museum, tokyo (japon) amicus orientalis endo 1961 [cf. clavaporella orientalis (endo 1961) vachard 1980 ] anatolipora konishi in johnson et konishi 1956 *anatolipora carbonica konishi in johnson et konishi 1956 1956 anatolipora carbonica n. gen. n. sp.konishi in johnson & konishi, pl. 1, fig. 1, 3, 5-6 & 8-9.e k yūs hū (japon): carbonifère, dinantien, viséen supérieur (katauchi fm); pl. 1, fig. 2, 4 & 7; pl. 2, fig. 3-4.central honshū (japon): carbonifère, dinantien, viséen supérieur (kotakigawa fm); pl. 2, fig. 12.s kyūs hū (japon): carbonifère, dinantien, viséen supérieur (kakisako fm).syntypes: pl. 1, fig. 2 & 4, lames minces n° giut-pp 7244a, 349-16, & giut-pp 7244b, 349-7; paratypes: pl. 1, fig. 1 & 3, lames minces n° gk-q 1010, katauchi-6, & gk-q 1011, katauchi-11, geological department, kyūshū university, fukuoka (japon) 10 geologia croatica 53/1 1961c (?) anatolipora carbonica .endo, pl. 7, fig. 3.o _ mine, nw mine-shi, yamaguchi-ken, honshū ( j a p o n ) : permien inférieur (zone à pseudoschwagerina , sous-zone à pseudofusulina vulgaris) 1963 anatolipora carbonica .johnson, pl. 64, fig. 1-9, extrait de konishi in johnson & konishi (1956: pl. 1, fig. 1-9) 1972 anatolipora carbonica .homann, pl. 3, fig. 24.nw reppwand, s hermagor, kärnten (autriche): sakmarien (oberer pseudoschwagerinenkalk); pl. 6, fig. 45.trogkofelkar, zottach-kogel trogkofel / creta di aip, kärnten (autriche): sakmarien (oberer pseudoschwagerinenkalk) 1972 (?) anatolipora ? cf. a. carbonica.homann, pl. 7, fig. 54.sw zollner see, w rattendorfer alpe, kärnten (autriche): carbonifère, silésien (höhere auernigschichten) 1975a (?) a n a t o l i p o r a sp.mamet & roux, pl. xi, fig. 6.cabrières, hérault (france): carbonifère, dinantien, viséen supérieur andrusoporella bystrický 1962 [synonyme postérieur de poikiloporella pia 1943, d’après holzer, 1967 ] andrusoporella brezovica bystrický 1967 [cf. poikiloporella brezovica (bystrický 1967) kollárová-andrusovová et bystricky ´ 1974] andrusoporella bystrickyi endo 1969 [cf. poikiloporella bystrickyi (endo 1969) emberger 1976 ] *andrusoporella fusani bystrický 1962 [synonyme postérieur de poikiloporella duplicata (pia 1920) 1943, d’après holzer, 1967 ] andrusoporella ? humilis endo 1969, nom. nud. [cf. poikiloporella humilis (endo 1969) emberger 1976, nom. nud. ] andrusoporella longobardica zanin buri 1965 [synonyme postérieur de poikiloporella duplicata (pia 1920) 1943, d’après holzer, 1967 ] anfractuosoporella chuvashov 1974 *anfractuosoporella uphaensis chuvashov 1974 1974 anfractuosoporella uphaensis n. gen. n. sp.chuvashov, pl. viii, fig. 1-5.w yekaterinburg, w oural (fédération de russie): assélien.holotype: pl. viii, fig. 1, lame mince n° π 208-32, collection b.i. chuvashov, unt ai sssr [institute of geology and geochemistry of urals, section of russian academy of sciences ], yekaterinburg (fédération de russie) anisoporella botteron 1961 anisoporella anisica (zanin buri 1965) hurka 1969 [= gyroporella anisica zanin buri 1965 ] 1965a gyroporella anisica n. sp.zanin buri, pl. 49, fig. 1-2.a & 6.a; pl. 50, fig. 1-6; pl. 51, fig. 1-2.valle dei grassi lunghi, w pasturo, valsassina, e lago di como, lombardia (italie): anisien inférieur (fm dei calcari de recoaro, niveau à dadocrinus gracilis ).holotype: pl. 50, fig. 2, lame mince n° gl 3c, coll. n° 1569, collection c. zanin buri, laboratorio di micropaleontologia, istituto di paleontolo gia, università di milano (italie) 1969 anisoporella anisica n. comb.hurka, p. 114, non figurée 1972c anisoporella anisica .ott, fig. 4, n° 1-3.karrer alm, weiße wand, tschirgant, e imst, tirol (autriche): anisien inférieur 11granier & grgasoviê: les algues dasycladales du permien et du trias... 1988 gyroporella .sartorio & venturini, p. 53 bas pars, extrait de zanin buri (1965a: pl. 49, fig. 2.a) *anisoporella occidentalis botteron 1961 1958 o l i g o p o r e l l a (?) n. sp.ellenberger, pl. 4, fig. 5.roc de la pêche, vanoise, savoie (france): “virglorien” (anisien); pl. 4, fig. 6 & 9; pl. 22, fig. 1.lac blanc, vanoise, savoie (france): “virglorien” (anisien); pl. 4, fig. 7-8.pas du lac, vanoise, savoie (france): “virglorien” (anisien); pl. 4, fig. 1015.croix de verdon, vanoise, savoie (france): “virglorien” (anisien) 1961 anisoporella occidentalis n. gen. n. sp.botteron, pl. iii, fig. 1-10; pl. iv, fig. 1-4; pl. v, fig. 1-2.cirques de dorchaux et de l’escuale, mont d’or, vaud (suisse): “virglorien” (anisien) moyen.holotype: pl. iii, fig. 2.a-b, spécimen n° 39 557; paratypes: pl. iii, fig. 1 & 3-10, spécimens n° 39 558, collection g. botteron, musée géologique de lausanne (suisse) anthracoporella pia 1920 anthracoporella girtyi roux ex mamet et roux in mamet et al. 1987 1979a (nom. nud.) anthracoporella girtyi n. sp.roux, pl. 10, fig. 6 & 9.girty creek, ellesmere, nunavut (canada): carbonifère, silésien, moscovien moyen ou plus jeune (fm nansen); pl. 11, fig. 6.girty creek, ellesmere, nunavut (canada): sakmarien (fm nansen).type: pl. 10, fig. 6, lame mince n° cgc 60994, commission géologique du canada, calgary (canada) 1987 anthracoporella girtyi n. sp.mamet & roux in mamet et al., pl. 10, fig. 6 & 9, extrait de roux (1979a: pl. 10, fig. 6 & 9); pl. 11, fig. 6, extrait de roux (1979a: pl. 11, fig. 6).type: pl. 10, fig. 6, lame mince n° cgc 60994, commission géologique du canada, calgary (canada) anthracoporella magnipora endo 1951 1951 anthracoporella magnipora n. sp.endo, pl. 10, fig. 4-5.sakamotozawa, hikoroichi-mura, kesen-gun, iwate-ken, honshū (japon): permien “inférieur”.“cotypes” (syntypes): pl. 10, fig. 4-5, lames minces n° 32 & 62, specimen (?) n° 10760, laboratory (department) of earth sciences, saitama universi ty, urawa (japon) 1956 anthracoporella magnipora .endo, pl. 22, fig. 1-2.unjo hill, miyamori-mura, iwate-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie inférieure) 1957 anthracoporella magnipora .endo, pl. 37, fig. 1.zenbutsuji-dani, taishaku-mura, hiba-gun, hiroshima-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie supérieure) 1961a anthracoporella magnipora .endo, pl. 1, fig. 6, extrait de endo (1951: pl. 10, fig. 4) 1963 anthracoporella magnipora .h. flügel, pl. 1, fig. 1.aladag / bademli, ne alanya (turquie): permien 1969 anthracoporella magnipora .endo, pl. vii, fig. 6.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina ) anthracoporella mercurii elliott 1968 1968a anthracoporella mercurii n. sp.elliott, pl. 1, fig. 8.wady bih, djebel hagab (oman): wordien (bih dolomite, zone à n e o s c h w a g e r i n a-v e r b e e k i n a).holotype: pl. 1, fig. 8, lame mince n° v.52035, collection g.f. elliott, british museum (natural history), london (royaume-uni) *anthracoporella spectabilis pia 1920 1919 stolleyla velebitana [sic].négris, pl. xxvi, fig. 3-4.khíos / chios (grèce): carbonifère 1920 anthracoporella spectabilis n. gen. n. sp.pia, pl. i, fig. 7.mte corona / kronalpe, pontebba / pontafel, friuli venezia giulia (italie): carbonifère, silésien; pl. i, fig. 8.tröpolach, gailtal, kärnten (autriche): carbonifère, silésien; pl. i, fig. 9-11.træië (slovénie): carbonifère, silésien (calcaires à fusulines).types: pl. i, fig. 7, lame mince n° 11; pl. i, fig. 8, lame mince n° lxxii/5; pl. i, fig. 9, lame mince n° ?; pl. i, fig. 10-11, lame mince n° cxviii/2, collection j. von pia, naturhistorisches museum, wien (autriche) 1928 anthracoporella spectabilis .pia, pl. xxi.pontebba / pontafel, friuli venezia giulia (italie): carbonifère, silésien (auernigschichten) 12 geologia croatica 53/1 1930 non anthracoporella cf. spectabilis.jodot, fig. 3, pl. l, fig. 2.col san colombano, bastia, corse (france): carbonifère, dinantien 1940 (?) anthracoporella spectabilis .makhaev, pl. i, fig. 8-10 & 12; pl. ii, fig. 6.berïozovaïa river, n oural (fédération de russie): carbonifère, silésien 1951 (?) anthracoporella sp.johnson.pl. 7, fig. 6-7.apache mts, texas (états-unis d’amérique): guadalupien (probablement ? capitanien) 1952a anthracoporella spectabilis .endo, pl. 12, fig. 6-7.n sakamotozawa, hikoroichi-mura, kesen-gun, iwate-ken, honshū (japon): carbonifère, mississipien 1952c anthracoporella spectabilis .endo, pl. 23, fig. 1.utatonami, o _ mi-mura, nishikubiki-gun, niigata-ken, honshū (japon): carbonifère, ouralien 1953b anthracoporella spectabilis .endo, pl. ix, fig. 13.mujinazawa valley, chichibu-gun, niigata-ken, honshū (japon): carbonifère, pennsylvanien 1954a (?) macroporella sp.konishi, pl. ii, fig. 18.kosaki, shimomatsukoma-mura, yatsushiro-gun, kumamotaken, kyūshū (japon): permien moyen (kosaki fm, zone à neoschwagerina-verbeeckina) 1956 (?) acanthoporella sp [sic].jones, fig. 4.8, extrait de johnson (1951: pl. 7, fig. 7) 1956 (?) ? anthracoporella spectabilis .maslov, pl. xii, fig. 1, extrait de makhaev (1940: pl. i, fig. 9); pl. xii, fig. 2, extrait de makhaev (1940: pl. i, fig. 8); pl. xii, fig. 3, extrait de makhaev (1940: pl. i, fig. 10) 1958 anthracoporella spectabilis .horiguchi, pl. 27, fig. 1-2 & 5.iwate-ken, honshū (japon): permien “inférieur” (myojinyama member) 1959 non anthracoporella spectabilis [= velomorpha kuzuensis, nom. nud.].konishi, pl. xxxi, fig. 14-23 1960 antracoporella spectabilis [s i c].bilgütay, pl. i, fig. 3-4.hasanoǧlan, e ankara (turquie): permien “inférieur” 1960 anthracoporella spectabilis .kochansky & herak, pl. i, fig. 6; pl. ii, fig. 1-3 & 6.vinac, bruπane, velebit mt (croatie): carbonifère, silésien; pl. ii, fig. 4.crne grede, velebit mt (croatie): permien “moyen”; pl. ii, fig. 5.boë, ne celje (slovénie): permien “inférieur”-”moyen” 1961 anthracoporella spectabilis .johnson, pl. 47, fig. 3, extrait de pia (1920: pl. i, fig. 8) 1961 anthracoporella .johnson, pl. 127, fig. 1, extrait de pia (1928: pl. xxi) 1962 anthracoporella spectabilis .h. flügel, fig. 1.waschbüchel, waidegg-stranig, kärnten (autriche): paléozoïque supérieur 1962 anthracoporella spectabilis .kochansky-devidé & milanoviê, pl. vi, fig. 1.sjerogoπte, rivière tara, monténégro (yougoslavie): sakmarien supérieur artinskien inférieur 1963 anthracoporella spectabilis .herak, fig. 29 (à gauche), extrait de kochansky & herak (1960: pl. ii, fig. 2-3); fig. 29 (à droite), extrait de kochansky & herak (1960: pl. i, fig. 6) 1963 anthracoporella spectabilis .herak & kochansky, pl. i, fig. 1.nagyberenás, bükk hegység (hongrie): carbonifère, silésien, moscovien supérieur 1963 anthracoporella spectabilis .johnson, pl. 8, fig. 3, extrait de pia (1920: pl. i, fig. 8); pl. 49, fig. 1-6, extrait de kochansky & herak (1960: pl. ii, fig. 1-6) 1963 (?) anthracoporella spectabilis .johnson, pl. 10, fig. 1, extrait de makhaev (1940: pl. i, fig. 9); pl. 10, fig. 2, extrait de makhaev (1940: pl. i, fig. 8); pl. 10, fig. 3, extrait de makhaev (1940: pl. i, fig. 10) 1963 anthracoporella limestone.johnson, pl. 9, fig. 1, extrait de pia (1928: pl. xxi) 1963 (?) anthracoporella spectabilis .maslov in bakhrameeba et al., pl. xv, fig. 1, extrait de makhaev (1940: pl. i, fig. 8); pl. xv, fig. 2, extrait de makhaev (1940: pl. i, fig. 9) 1964 anthracoporella spectabilis .bebout & coogan, pl. 169, fig. 1-4.forage humble n° 1, rough draw, fischer county, texas (états-unis d’amérique): wolfcampien 1964 anthracoporella spectabilis .rácz, pl. v, fig. 4-7.s cármenes, león (espagne): carbonifère, silésien, bashkirien supérieur (fm san emiliano, zone à profusulinella , sous-zone a) 1965 anthracoporella spectabilis .ramovπ & kochansky-devidé, pl. viii, fig. 5.ortnek (slovénie): permien 1966 anthracoporella spectabilis .e. flügel, pl. 6, fig. 1.kärnten (autriche): permien inférieur (oberer pseudoschwagerinenkalk) 1966 anthracoporella spectabilis .kochansky-devidé & ramovπ, pl. vi, fig. 5.w karavanke (slovénie): carbonifère, silésien 1966 anthracoporella spectabilis .rácz, pl. v, fig. 27.n cervera de pisuerga, n palencia (espagne): carbonifère, silésien, moscovien (zone à fusulinella ) 13granier & grgasoviê: les algues dasycladales du permien et du trias... 1968a anthracoporella spectabilis .elliott, pl. 2, fig. 1-2.djebel busyah (oman): permien (galet dans un conglomérat ? triasique) 1969 anthracoporella spectabilis .endo, pl. ix, fig. 1-2.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à neoschwageri na simplex / partie inférieure) 1970a anthracoporella spectabilis .kochansky-devidé, pl. xxii, fig. 3.w karavanke (slovénie): permien inférieur (trogkofelkalk) 1970b anthracoporella spectabilis .kochansky-devidé, pl. iv, fig. 1 pars.velebit mt (croatie): carbonifère, silésien, moscovien-kasimovien 1970 anthracoporella spectabilis .l.t. nguyên, pl. v, fig. 1-5.núi còm, hòn chông, se hà tiên, w hô chi minh-ville / saïgon (viêt-nam): kungurien supérieur ? kazanien inférieur (núi còm limestones); pl. vi, fig. 1-2.nhommarath (laos): sakmarien (nhommarath limestones) 1971 anthracoporella spectabilis .ramovπ, pl. 2, fig. 1.savske jame, ne planina, n jesenice (slovénie): carbonifère, silésien, gzhélien, orenburgien 1972 anthracoporella spectabilis .homann, pl. 3, fig. 23.untere ringmauer, rattendorfer alpe, friuli venezia giulia (italie): sakmarien (rattendorfer schichten, unterer pseudoschwagerinenkalk) 1973 anthracoporella spectabilis .kochansky-devidé et al., pl. 3, fig. 2.karavanke (slovénie): carbonifère, silésien (orenburg-stufe) 1974 anthracoporella spectabilis .chuvashov, pl. vi, fig. 1-6.w yekaterinburg, w oural (fédération de russie): assélien 1974 (?) anchicodium sindbadi.chuvashov, pl. i, fig. 1-4.w yekaterinburg, w oural (fédération de russie): assélien 1976 anthracoporella spectabilis .vachard in montenat et al., pl. xix, fig. 2.djebel akhdar, oman mts (oman): murghabien-djulfien 1977 anthracoporella spectabilis .e. flügel, pl. 1/1.treßdorfer höhe, kärnten (autriche): assélien (unterer pseudoschwagerinenkalk) 1978 anthracoporella spectabilis .kulik, pl. iv, fig. 1-2, 4-5 & 7.shakhtau massif, bashkirskaya (fédération de russie): sakmarien, tastubien (zone à pseudofusulina moelleri, sous-zone ts1); pl. iv, fig. 3.shakhtau massif, bashkirskaya (fédération de russie): sakmarien, tastubien (zone à p s e u d o f u s u l i n a m o e l l e r i, sous-zone ts2); pl. iv, fig. 6.shakhtau massif, bashkirskaya (fédération de russie): sakmarien, sterlitimakien (zone à pseudofusulina callosa , sous-zone st1) 1978 anthracoporella spectabilis .ramovπ, fig. 6.2.»rni vrh, e planina, n jesenice (slovénie): carbonifère, silésien 1979 anthracoporella spectabilis .d.t. nguyên, pl. 29, fig. 2.damrey, w cambodge (cambodge): permien; pl. 29, fig. 3-4 & 11.a.pouthisat, w cambodge (cambodge): permien supérieur (zone à y a b e i n a e t lepidolina) 1979 anthracoporella spectabilis .ramovπ & kochansky-devidé, pl. 1, fig. 1 & 3 pars.n julijske alpe (slovénie): carbonifère, silésien, gzhélien (oberer auernigschichten) 1980 anthracoporella spectabilis .e. flügel & flügel-kahler, pl. 7, fig. 7.ne col mezzodì, forni avoltri, friuli venezia giulia (italie): permien inférieur (kalkbrekzie) 1980 anthracoporella spectabilis .ramovπ, fig. 6.2-3.dolina, træië (slovénie): carbonifère supérieur 1980 anthracoporella spectabilis .vachard, pl. 5, fig. 2 pars & 4 pars; pl. 22, fig. 13.langarel, dunga (afghanistan): murghabien moyen-supérieur; pl. 5, fig. 3 pars; pl. 23, fig. 6-8.abtchakan, altimour (afghanistan): murghabien supérieur 1980 anthracoporella .vachard, pl. 7, fig. 3 pars.khwahan, tezak (afghanistan): assélien 1981 anthracoporella spectabilis .ramovπ & kochansky-devidé, pl. 1, fig. 5 pars.s tof, gozd-martuljek kranjska gora (slovénie): carbonifère, silésien, gzhélien 1981 anthracoporella spectabilis .vachard in vachard & montenat, pl. 3, fig. 1.khwaja bahadur, tezak (afghanistan): murghabien moyen 1982 anthracoporella spectabilis .milanoviê, pl. x, fig. 3 pars.vinica, w varaædin, hrvatsko zagorje (croatie): carbonifère, silésien, moscovien, kashirskien (galet dans un conglomérat éocène) 1982 anthracoporella spectabilis .mu, pl. v, fig. 7.xizang / tibet (chine populaire): permien “inférieur” / partie inférieure 14 geologia croatica 53/1 1984 anthracoporella spectabilis .e. flügel, kochansky-devidé & ramovπ, pl. 29, fig. 3.straæa, bled (slovénie): permien “moyen” 1984 anthracoporella spectabilis .nakamura & chisaka, pl. 5, fig. 8-12.mt atagoyama, chôshi-shi, chibaken, honshū (japon): permien “supérieur” (takagami conglomerate) 1986a anthracoporella spectabilis .d.t. nguyên, pl. 9, fig. 1.b; pl. 10, fig. 2 pars.pursat (cambodge): murghabien supérieur midien 1986b anthracoporella spectabilis .d.t. nguyên, pl. 15, fig. 9.guguk bulat, padang, sumatra (indonésie): permien 1987 anthracoporella spectabilis .delvolvé et al., pl. 1, fig. 5.col d’ibardin, n bera, navarra (espagne): carbonifère, silésien, moscovien, kashirskien 1987 anthracoporella spectabilis .e. flügel, pl. 8, fig. 1 & 4.kärnten (autriche): permien inférieur 1987 anthracoporella .e. flügel, pl. 7, fig. 5.kärnten (autriche): permien inférieur 1987 (?) anthracoporellid algae.e. flügel, pl. 8, fig. 8.kärnten (autriche): permien inférieur 1988 anthracoporella spectabilis .fontaine & suteethorn, pl. 2, fig. 14-15.khao kan ban dai, prachuap khiri khan, ssw krung thep / bangkok (thaïlande): midien-djulfien 1988 anthracoporella spectabilis .sartorio & venturini, p. 36, haut.mte pizzul, e paularo, w pontebba / pontafel, friuli venezia giulia (italie): carbonifère, silésien 1989 anthracoporella spectabilis .d.t. nguyên, pl. 24, fig. 1.a.bukit pendopo, s sumatra (indonésie): murghabien 1989 non anthracoporella spectabilis .d.t. nguyên, pl. 35, fig. 2.b.guguk bulat, sumatra (indonésie): murghabien 1989 permocalculus fragilis .d.t. nguyên, pl. 35, fig. 2.a.guguk bulat, sumatra (indonésie): murghabien 1990 anthracoporella spectabilis .nowiński, pl. 1, fig. 1.a-c; pl. 2, fig. 3.urnetoppen, hornsund, s spitzberg (norvège): sakmarien (treskelodden fm); pl. 1, fig. 2; pl. 2, fig. 2.treskelen, s hornsund, s spitzberg (norvège): sakmarien (treskelodden fm) 1991 anthracoporella .krainer, fig. 2 pars.garnitzenberg / mte carnizza, s hermagor, kärnten (autriche): carbonifère, silésien, gzhélien (auernig fm, gugga limestone); fig. 3 pars.kronalpe / mte corona, s hermagor, kärnten (autriche): carbonifère, silésien, gzhélien (auernig fm) 1991 anthracoporella spectabilis .krainer, fig. 4.kronalpe / mte corona, s hermagor, kärnten (autriche): carbonifère, silésien, gzhélien (auernig fm) 1991 a n t h r a c o p o r e l l a .riding & guo, fig. 7.trogkofel / creta di aip, friuli venezia giulia (italie): permien inférieur (trogkofelkalk) 1991a anthracoporella spectabilis .wu, pl. i, fig. 3; pl. ii, fig. 4.xiangbo, longli county, guangxi (chine populaire): guadalupien, ‘maokouan’ 1991b anthracoporella spectabilis .wu, pl. 19, fig. 3, extrait de wu (1991a: pl. i, fig. 3); pl. 20, fig. 4, extrait de wu (1991a: pl. ii, fig. 4) 1992 a n t h r a c o p o r e l l a .krainer, fig. 31.kronalpe / mte corona, s hermagor, kärnten (autriche): carbonifère, silésien, gzhélien (auernig fm); pl. 6; fig. 3 pars.garnitzenberg / mte carnizza, s hermagor, kärnten (autriche): carbonifère, silésien, gzhélien (auernig fm) 1992 anthracoporella spectabilis .krainer, pl. 6; fig. 4.w kronalpe / mte corona, s hermagor, kärnten (autriche): carbonifère, silésien, gzhélien (auernig fm) 1993 non anthracoporella spectabilis .dawson, pl. 9, fig. 1.n sara buri, n krung thep / bangkok (thaïlande): sakmarien-yahtashien (rat buri limestone) 1993 anthracoporella spectabilis .kahler & krainer, pl. 67, fig. 3.schulterkofel, kärnten (autriche): carbonifère, silésien, gzhélien supérieur 1995 anthracoporella .krainer, pl. 38, fig. 4-5; pl. 39, fig. 6; pl. 41, fig. 1.garnitzenberg / mte carnizza, s hermagor, kärnten (autriche): carbonifère, silésien, gzhélien (auernig fm); pl. 39, fig. 2 pars.s hermagor, kärnten (autriche): carbonifère, silésien, gzhélien (auernig fm); pl. 39, fig. 5 pars; pl. 40, fig. 3.nw kronalpe / mte corona, s hermagor, kärnten (autriche): carbonifère, silésien, gzhélien (auernig fm); pl. 41, fig. 2.gugga, garnitzenberg / mte carnizza, s hermagor, kärnten (autriche): carbonifère, silésien, gzhélien (auernig fm); pl. 41, fig. 4 pars.ne garnitzenberg / mte carnizza, s hermagor, kärnten (autriche): carbonifère, silésien, gzhélien (auernig fm) 1995 anthracoporella spectabilis .krainer, pl. 40, fig. 5-6.garnitzenberg / mte carnizza, s hermagor, kärnten (autriche): carbonifère, silésien, gzhélien (auernig fm); pl. 41, fig. 5.ne garnitzenberg / mte 15granier & grgasoviê: les algues dasycladales du permien et du trias... carnizza, s hermagor, kärnten (autriche): carbonifère, silésien, gzhélien (auernig fm); pl. 41, fig. 6.kronalpe / mte corona, s hermagor, kärnten (autriche): carbonifère, silésien, gzhélien (auernig fm) 1997 a n t h r a c o p o r e l l a .samankassou, fig. 7.3-4.trogkofel / creta di aip, friuli venezia giulia (italie): carbonifère, silésien, gzhélien (rattendorf group, unterer pseudoschwagerinenkalk) 1997 anthracoporella spectabilis .sremac & aljinoviê, pl. iii, fig. 7 pars.kriæ potok, mrzla vodica, gorski kotar (croatie): assélien 1998 a n t h r a c o p o r e l l a .samankassou, fig. 5-6.auernig, s hermagor, kärnten (autriche): carbonifère, silésien, gzhélien (auernig group, auernig fm) 1999 a n t h r a c o p o r e l l a .samankassou, fig. 3.s hermagor, kärnten (autriche): carbonifère, silésien, gzhélien (rattendorf group, unterer pseudoschwagerinenkalk) anthracoporella uralensis chuvashov 1974 1974 anthracoporella uralensis n. sp.chuvashov, pl. vii, fig. 1-4.w yekaterinburg, w oural (fédération de russie): assélien; pl. vii, fig. 5.d’après chuvashov et al. (1993): chusovaya river, nw yekaterinburg (fédération de russie): assélien.holotype: pl. vii, fig. 5, lame mince n° π 208-31, collection b.i. chuvashov, unt ai sssr [institute of geology and geochemistry of urals, section of russian academy of sciences ], yekaterinburg (fédération de russie) 1993 anthracoporella uralica [s i c] anthracoporella uralensis .chuvashov et al., pl. 14, fig. 6, extrait de chuvashov (1974: pl. vii, fig. 5) anthracoporella vicina kochansky et herak 1960 1960 anthracoporella vicina n. sp.kochansky & herak, pl. i, fig. 2-4.okroænik, vitanje, n celje (slovénie): carbonifère, ouralien; pl. i, fig. 1 & 5.vinac, bruπane, velebit mt (croatie): carbonifère, fig. 2 anthracoporella vicina (kochansky & herak, 1960, pl. i, fig. 4), x55. fig. 3 anthracoporella vicina (kochansky & herak, 1960, pl. i, fig. 3), x22. 16 geologia croatica 53/1 o u r a l i e n.holotype: pl. i, fig. 3, lame mince n° 1835, collection v. kochansky-devidé, geoloπkopaleontoloπki zavod, prirodoslovno-matematiëki fakultet [geological and palaeontological institute, faculty of sciences ], zagreb (croatie) 1966 anthracoporella vicina .kochansky-devidé & ramovπ, pl. vi, fig. 3-4.w karavanke (slovénie): carbonifère, silésien 1970a anthracoporella vicina .kochansky-devidé, pl. xxii, fig. 4.w karavanke (slovénie): permien inférieur (trogkofelkalk) 1978 anthracoporella vicina .ramovπ, fig. 6.1.javorniπki rovt, n javornik, ne jesenice (slovénie): carbonifère, silésien 1986 non anthracoporella viêina [sic].mirkoviê, pl. iii, fig. 2.1.nikπiêka æupa, monténégro (yougoslavie): permien “moyen” (trogkofelkalk) archaeocladus endo 1956 archaeocladus eminensis endo 1968, nom. nud. 1968b (nom. nud.) archaeocladus eminensis n. sp.endo, “chart”, non figurée.type non figuré *archaeocladus seriatus endo 1956 1956 archaeocladus seriatus n. gen. n. sp.endo, pl. 26, fig. 3-4.sakaishi, agano-mura, hannō-shi, irumagun, saitama-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne).syntypes: pl. 26, fig. 3-4, lame mince n° 333, department of earth sciences, saitama university, urawa (japon) 1961a archaeocladus seriatus .endo, pl. 4, fig. 10, extrait de endo (1956: pl. 26, fig. 4) 1963 archaeocladus seriatus .johnson, pl. 50, fig. 1-2, extrait de endo (1956: pl. 26, fig. 3-4) atractyliopsis pia ex accordi 1956 atractyliopsis carnica e. flügel 1966 1963 a t r a c t y l i o p s i s.herak (pantiê), fig. 40.nikπiêka æupa, monténégro (yougoslavie): permien “supérieur” 1965 atractyliopsis sp.güvenç, pl. a8, fig. 6.w taurus (turquie): permien “inférieur” terminal 1966 atractyliopsis carnica n. sp.e. flügel, fig. 2; pl. 4, fig. 1-3; pl. 5, fig. 1-4.seehöhe, e zweikofel, kärnten (autriche): permien inférieur (oberer pseudoschwagerinenkalk).holotype: pl. 4, fig. 2, lame mince n° fpt. 103/1 (371), collection e. flügel, botan.-paläobotanische abteilung, senckenbergmuseum, frankfurt am main (allemagne) 1969 (?) atractyliopsis cf. c a r n i c a .endo, pl. xxiii, fig. 1-4.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina ) 1972 atractyliopsis carnica .homann, pl. 3, fig. 19; pl. 5, fig. 41.nw zottach-kogel, kärnten (autriche): sakmarien (rattendorfer schichten, oberer pseudoschwagerinenkalk) 1977 atractyliopsis carnica .e. flügel, pl. 4/4.kärnten (autriche): assélien (oberer pseudoschwagerinenkalk) 1978 (?) ? atractyliopsis carnica .kulik, pl. vii, fig. 7-9.shakhtau massif, bashkirskaya (fédération de russie): assélien, kurmainskien (zone à schwagerina sphaerica et pseudofusulina firma, zone ass3) 1979 atractyliopsis carnica .e. flügel, pl. 1, fig. 5 pars.zottach-kogel, kärnten (autriche): assélien (oberer pseudoschwagerinenkalk) 1979 atractyliopsis carnica .zagorodnjuk, pl. i, fig. 6.voskresenskoye, bashkirskaya (fédération de russie): carbonifère, silésien, gzhélien (c3c) 1980 atractyliopsis carnica .e. flügel & flügel-kahler, pl. 2, fig. 1-5 & 7-8.ne col mezzodì, forni avoltri, friuli venezia giulia (italie): permien inférieur (trogkofelkalk); pl. 2, fig. 6.ne col mezzodì, forni avoltri, friuli venezia giulia (italie): permien inférieur (kalkbrekzie) 1980 atractyliopsis carnica .e. flügel, pl. 5, fig. 1-2.rio valp, forni avoltri, friuli venezia giulia (italie): permien inférieur (kalkbrekzie); pl. 5, fig. 3.forni avoltri, friuli venezia giulia (italie): permien 17granier & grgasoviê: les algues dasycladales du permien et du trias... inférieur (trogkofelkalk); pl. 5, fig. 5.forni avoltri, friuli venezia giulia (italie): permien inférieur (treßdorfer kalk) 1980 a t r a c t y l i o p s i s.e. flügel, pl. 5, fig. 4.forni avoltri, friuli venezia giulia (italie): permien inférieur; pl. 7, fig. 4.forni avoltri, friuli venezia giulia (italie): permien inférieur (treßdorfer kalk, “extraklast”) 1986 non atractyliopsis carnica atractyliopsis carnice [sic] atractoliopsis carnica [sic] altractyliopsis carnica [s i c].mirkoviê, pl. i, fig. 3.1.vasiljeviêi, nikπiêka æupa, monténégro (yougoslavie): permien “moyen” (trogkofelkalk); pl. iii, fig. 2.2 & 3.1.kuta, nikπiêka æupa, monténégro (yougoslavie): permien “moyen” (trogkofelkalk) 1988 atractyliopsis carnica .e. flügel & kraus, pl. 3, fig. 2 pars & 3 pars.e san cándido / innichen, valle di sesto / sextental, trentino alto adige (italie): permien inférieur (sexten breccia) 1988 dasycladaceans e. flügel & kraus, pl. 3, fig. 6 pars.e san cándido / innichen, valle di sesto / sextental, trentino alto adige (italie): permien inférieur (sexten breccia) 1991 altractyliopsis.riding & guo, fig. 3.trogkofel / creta di aip, friuli venezia giulia (italie): permien inférieur (trogkofelkalk) 1994 atractyliopsis carnica .pantiê-prodanoviê, pl. iv, fig. 5 & 8.neëaje, petkovica, cer mt, sw beograd, serbie (yougoslavie): permien supérieur 1997 atractyliopsis carnica .sremac & aljinoviê, pl. iii, fig. 4 pars.kosmaëev brijeg, mrzla vodica, gorski kotar (croatie): assélien atractyliopsis darariensis elliott 1968 1968a atractyliopsis darariensis n. sp.elliott, pl. 2, fig. 3-5.ora, mosul liwa, n irak (irak): permien “supérieur” (darari fm ou upper chia zairi fm).holotype: pl. 2, fig. 5, lame mince n° v.52037; paratypes: pl. 2, fig. 3, lame mince n° v.52015; pl. 2, fig. 4, lame mince n° v.52037, collection g.f. elliott, british museum (natural history), london (royaume-uni) 1971 atractyliopsis darariensis .elliott, pl. 118, fig. 3, extrait de elliott (1968a: pl. 2, fig. 3) atractyliopsis fecundus kordé 1965 [espèce exclue des dasycladales, l’holotype (pl. lv, fig. 6) est un foraminifère fusulinoïde d’après vachard, 1980 ] 1965 atractyliopsis fecundus n. sp.kordé, pl. lv, fig. 6.chanakhchi (arménie): guadalupien; pl. lv, fig. 8.dorasham 2, dzhul’fa, nakhichevan’ (azerbaïdjan): guadalupien.holotype: pl. lv, fig. 6, lame mince n° 2307/20, collection k.b. kordé, moscou (fédération de russie) 1965 non atractyliopsis fecundus n. sp. [= atractyliopsis lastensis].kordé, pl. lv, fig. 7 *atractyliopsis lastensis accordi 1956 1927 mizzia yabei.ogilvie gordon, pl. ix, fig. 10.plesch d’inaz, val gardena / grödnertal, trentino alto adige (italie): permien supérieur (bellerophon limestone); pl. xiii, fig. 6 pars.mte pic / pitschberg, santa cristina / st. christina, val gardena / grödnertal, trentino alto adige (italie): permien “supérieur” (hoher horizont) 1937 (nom. nud.) atractyliopsis n. sp.pia, pl. 10(94), fig. 5.neuprags, e póstal / burgstalls, trentino alto adige (italie): permien supérieur (bellerophon limestone) 1 9 3 7 (?) (nom. nud.) a t r a c t y l i o p s i s n. sp. [? = kochanskiella tulipa].pia, pl. 10(94), fig. 6.schloss thurn, val badia / gadertal, trentino alto adige (italie): permien supérieur (bellerophon limestone) 1956 atractyliopsis lastensis n. gen. n. sp.accordi, pl. 8, fig. 1-3; pl. 10, fig. 1 & 4-11.val cordévole, véneto (italie): permien supérieur (bellerophon fm / “b e l l e r o p h o n-zone”); pl. 10, fig. 2-3 & 12.val gardena / grödnertal, trentino alto adige (italie): permien supérieur (bellerophon fm / “bellerophonz o n e ” ).types: pl. 10, fig. 1-2, 4-6 & 9-11, lame mince n° n.a1, collection b. accordi, geological institute of the ferrara university (italie) 1961a atractyliopsis lastensis.endo, pl. 7, fig. 8, extrait de accordi (1956: pl. 8, fig. 1) 1963 atractyliopsis lastensis.johnson, pl. 50, fig. 5, extrait de accordi (1956: pl. 10, fig. 1) 1963 atractyliopsis sp.johnson, pl. 50, fig. 6, extrait de pia (1937: pl. 10(94), fig. 5) 1963 (?) atractyliopsis sp. [? = kochanskiella tulipa].johnson, pl. 50, fig. 7, extrait de pia (1937: pl. 10(94), fig. 6) 18 geologia croatica 53/1 1963 a t r a c t y l i o p s i s.praturlon, fig. 3 pars.val pesarina, friuli venezia giulia (italie): permien supérieur (bellerophon fm / “bellerophon-zone”) 1965 atractyliopsis fecundus n. sp.kordé, pl. lv, fig. 7.chanakhchi (armenié): guadalupien 1967 non atractyliopsis lastensis [= aciculella s p .].herak & ©kalec, pl. i, fig. 2-3.bregana, w zagreb, samoborsko gorje mts (croatie): permien “supérieur” 1969 atractyliopsis lastensis.kochansky-devidé & sliπkoviê, pl. ii, fig. 3-4.©uljci, e foëa (bosnie-herzégovine): permien “supérieur” 1969 atractyliopsis lastensis.pantiê, pl. ii, fig. 4.ruisseau kopljeviê, pocerina, w serbie (yougoslavie): permien “supérieur” 1971 atractyliopsis lastensis.elliott, pl. 119, fig. 4.plesch d’inaz, val gardena / grödnertal, trentino alto adige (italie): permien supérieur (bellerophon limestone) 1986 atractyliopsis lastensis.mirkoviê, pl. viii, fig. 1 pars; pl. ix, fig. 2.bjeloπevina, monténégro (yougoslavie): permien supérieur (bellerophon limestone); pl. xi, fig. 1.1; pl. xiii, fig. 2 pars.dugo brdo, monténégro (yougoslavie): permien supérieur (bellerophon limestone); pl. xi, fig. 3.2.vasiljeviêi, nikπiêka æupa, monténégro (yougoslavie): permien supérieur (bellerophon limestone) 1987 atractyliopsis lastensis.noé, pl. 24, fig. 1 pars.mte ruche, nw ampezzo, friuli venezia giulia (italie): permien supérieur (bellerophon fm / partie supérieure); pl. 29, fig. 7 pars.diérico, s paularo, w pontebba / pontafel, friuli venezia giulia (italie): permien supérieur (bellerophon fm / partie supérieure) 1988 atractyliopsis lastensis.buggisch & noé, pl. 1, fig. 6 pars.mte ruche, nw ampezzo, friuli venezia giulia (italie): permien supérieur (bellerophon fm / partie supérieure) 1988 atractyliopsis.deloffre, pl. 4, fig. 18, extrait de pia (1937: pl. 10(94), fig. 5) 1988 (?) atractyliopsis [? = kochanskiella tulipa].deloffre, pl. 4, fig. 17, extrait de pia (1937: pl. 10(94), fig. 6) 1988 atractyliopsis lastensis.fontaine & suteethorn, pl. 3, fig. 6.khao kan ban dai, prachuap khiri khan, ssw krung thep / bangkok (thaïlande): midien-djulfien 1988 atractyliopsis lastensis.sartorio & venturini, p. 39, haut.digonera, n rocca piétore s andraz, veneto (italie): permien “supérieur” 1993 atractyliopsis lastensis.vachard et al., pl. i, fig. 9.s ermióni, argolís (grèce): djulfien (galet dans une “coulée boueuse” kimméridgienne de la fm de potami) 1994 atractyliopsis lastensis.pantiê-prodanoviê, pl. iv, fig. 6-7.neëaje, petkovica, cer mt, sw beograd, serbie (yougoslavie): permien supérieur atractyliopsis quadratus endo 1956 [espèce exclue des dasycladales, l’holotype (pl. 23, fig. 1) est un débris quelconque d’après vachard, 1980 ] 1952a a t r a c t y l i o p s i s (?) sp.endo, pl. 12, fig. 4 (d’après endo, 1956).sakamotozawa, hikoroichi-mura, kesen-gun, iwate-ken, honshū (japon): permien “moyen” 1956 atractyliopsis quadratus n. sp.endo, pl. 23, fig. 1.nishihara, tonara, tanuma-machi, togichi-ken, h o n s hū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne).holotype: pl. 23, fig. 1, lame mince n° 216, department of earth sciences, saitama university, urawa (japon) atractyliopsis tezakensis vachard in vachard et montenat 1981, non 1980 1 9 8 0 (nom. nud.) atractyliopsis tezakensis n. sp.vachard, pl. 4, fig. 2.a; pl. 24, fig. 8.khwaja bahadur, tezak (afghanistan): artinskien inférieur; pl. 24, fig. 7.dacht naw, tezak (afghanistan): artinskien inférieur.type non désigné 1981 atractyliopsis tezakensis n. sp.vachard in vachard & montenat, pl. 5, fig. 11; pl. 6, fig. 3 & 6.khwaja bahadur, tezak (afghanistan): artinskien; pl. 6, fig. 5, extrait de vachard (1980: pl. 24, fig. 8).holotype: pl. 6, fig. 5, lame mince n° iva 76-249a; paratypes: pl. 5, fig. 11, lame mince n° iva 76249a; pl. 6, fig. 3, lame mince n° iva 387 (non pl. 6, fig. 6, lame mince n° iva 76-25), collection d. vachard, institut de géologie igal, paris (france) 19granier & grgasoviê: les algues dasycladales du permien et du trias... beresella makhaev ex kulik 1964 beresella bilgutayae güvenç 1966, non 1965 [synonyme postérieur de beresella polyramosa kulik 1964, d’après mamet et roux in mamet et al. , 1987] beresella polyramosa kulik 1964 1 9 5 4 (nom. nud.) b e r e s e l l a .rauzer-chernoussova & dalmatskaja, pl. vi, fig. 11.se moscou (fédération de russie): carbonifère, silésien, moscovien, podolskien 1956 dvinella comata .maslov, pl. xiii, fig. 1-2 & 5; pl. xix, fig. 2.kuybyshev (fédération de russie): carbonifère, silésien 1957 (nom. nud.) eomizzia igoi n. gen. n. sp.endo & horiguchi, pl. xiii, fig. 4.kamitakara-mura, fukuji, gifuken, honshū (japon): carbonifère, silésien (ichinotani group, zone à p r o f u s u l i n e l l a ).“syntypes”: pl. xiii, fig. 4, lame mince n° 602, department of earth sciences, saitama university, urawa (japon) 1 9 5 7 non (nom. nud.) eomizzia igoi n. gen. n. sp. [= donezella lutugini].endo & horiguchi, pl. xiii, fig. 2-3.kamitakara-mura, fukuji, gifu-ken, honshū (japon): carbonifère, silésien (ichinotani group, zone à profusulinella ).“syntypes”: pl. xiii, fig. 2, lame mince n° 600; pl. xiii, fig. 3, lame mince n° 601, department of earth sciences, saitama university, urawa (japon) 1961a dvinella comata .endo, pl. 8, fig. 5, extrait de endo & horiguchi (1957: pl. xiii, fig. 4 = “e o m i z z i a igoi”) 1963 dvinella comata .johnson, pl. 12, fig. 1, extrait de maslov (1956: pl. xiii, fig. 2 = “dvinella comata”); pl. 12, fig. 2, extrait de maslov (1956: pl. xix, fig. 2 = “dvinella comata”); pl. 12, fig. 3, extrait de maslov (1956: pl. xiii, fig. 5 = “dvinella comata”); pl. 13, fig. 1.shikoku (japon): carbonifère, pennsylvanien 1963 dvinella.johnson, pl. 11, fig. 5.shikoku (japon): carbonifère, pennsylvanien 1963 beresella erecta .maslov in bakhrameeba et al., pl. xv, fig. 5, extrait de maslov (1956: pl. xiii, fig. 5 = “dvinella comata”) 1964 beresella polyramosa n. sp.kulik, pl. viii, fig. 2-3.krasnoï polyatsy, s kuybyshev (fédération de russie): carbonifère, silésien, moscovien, kashirskien.holotype: pl. viii, fig. 2, lame mince n° 3438/4 (non 3438/2) 1965 (nom. nud.) beresella bilgütayae n. sp.güvenç, pl. a.10, fig. 1.a.vallée du dikenli dere, alanya (turquie): carbonifère, silésien, bashkirien.holotype: pl. xxxii, fig. 1.a, lame mince n° t.g. d-8-27, collec tion t. güvenç, laboratoire de micropaléontologie, faculté des sciences de paris (france) 1966a beresella bilgütayae n. sp.güvenç, pl. xxxii, fig. 1.a, extrait de güvenç (1965: pl. a.10, fig. 1.a). holotype: pl. xxxii, fig. 1.a, lame mince n° t.g. d-8-a-27, collection t. güvenç, laboratoire de micropaléontologie, faculté des sciences de paris (france) 1967 dvinella comata.rich, pl. 125, fig. 1-2, 4, 11 & 14.s egan range, nevada (états-unis d’amérique): carbonifère, pennsylvanien, ‘atokan’ inférieur (zone à p r o f u s u l i n e l l a ); pl. 125, fig. 15 pars.s egan range, nevada (états-unis d’amérique): carbonifère, pennsylvanien, ‘atokan’ supérieur (zone à f u s u l i n e l l a); pl. 125, fig. 17.burbank hills, utah (états-unis d’amérique): carbonifère, pennsylvanien, ‘des moinesian’ inférieur-moyen 1973 (?) beresella cf. polyramosa.mamet & rudloff, pl. 5, fig. 1.hawley mt, idaho (états-unis d’amérique): carbonifère, silésien, moscovien; pl. 5, fig. 2-4.blind fiord, ellesmere, nunavut (canada): carbonifère, silésien, moscovien moyen 1976 beresella sp.bogush & juferev, pl. vi, fig. 4.kunge-saj, balkhash (kazakhstan): carbonifère, silésien 1976 (?) b e r e s e l l a cf. p o l i r a m o s a [s i c].bogush & juferev, pl. vi, fig. 3.balkhash (kazakhstan): carbonifère, silésien, moscovien (zone à aljutovella cybaea) 1979 beresella ex gr. polyramosa.mamet et al., pl. 1, fig. 4 pars.blind fiord, ellesmere, nunavut (canada): assélien supérieur ou sakmarien inférieur (fm belcher channel) 1979a beresella ex gr. b. polyramosa.roux, pl. 13, fig. 6-8, 10-15, 17 & 19.glacier de wood, ellesmere, nunavut (canada): carbonifère, silésien, moscovien moyen ou plus jeune (fm otto fiord); pl. 13, fig. 9, 16 & 18.girty creek, ellesmere, nunavut (canada): carbonifère, silésien, moscovien moyen ou plus jeune (fm nansen) 20 geologia croatica 53/1 1986 beresella polyramosa .groves, fig. 6.6-10.lemhi canyon, ne howe, snake river plain, idaho (étatsunis d’amérique): carbonifère, pennsylvanien, ‘atokan’ (snaky canyon fm, bloom member) 1987 beresella ex gr. b. polyramosa.mamet et al., pl. 13, fig. 6-19, extrait de roux (1979a: pl. 13, fig. 6-19) 1988 (?) beresella.deloffre, pl. 1, fig. 1, extrait de mamet & rudloff (1973: pl. 5, fig. 4); pl. 1, fig. 2, extrait de mamet & rudloff (1973: pl. 5, fig. 3) 1991 (?) beresella cf. b. polyramosa.mamet, pl. iii, fig. d, extrait de mamet & rudloff (1973: pl. 5, fig. 3) 1993 beresella polyramosa .chuvashov et al., pl. 13, fig. 4.ural river (fédération de russie): carbonifère, silésien, moscovien (urtasymsk suite) chinianella ott ex granier et deloffre 1994, non 1967 chinianella carpatica (bystrický 1967) granier et al. 1995 [= heteroporella carpatica bystrický 1967] 1965 diplopora sp.montanari, fig. 4.mte pellegrino, s mondello n palermo, sicile (italie): trias supérieur 1967b heteroporella carpatica n. sp.bystrický, pl. xv, fig. 1-2 & 4-5; pl. xvi, fig. 4.nw tisovec, m u r áňska planina (slovaquie): norien (furmaneckalk); pl. xv, fig. 3.nw tisovec, muráňska planina (slovaquie): norien (furmaneckalk), ou d’après bystrický (1986): norien, alaunien (h e t e r o p o r e l l a t a xon-range superzone).holotype: pl. xv, fig. 3, lame mince n° 2257, collection j. bystrick ý, geological institute, slovak academy of sciences, bratislava (slovaquie) 1 9 6 7 (nom. nud.) chinianella zankli n. sp.ott, fig. 5, n° 1-14; pl. 13, fig. 2-3.s dürreckberg, hoher göll, berchtesgaden, bayern (allemagne): norien-rhétien (dachsteinkalk).holotype: pl. 13, fig. 2, lame mince n° e 109 a/67, collection e. ott, bayerische staatssammlung für paläontologie und historische geologie, münchen (allemagne) 1968 heteroporella zankli n. comb.ott, p. 258, non figurée 1969 (nom. nud.) chinianella zankli.johnson, pl. 37, fig. 1-14, extrait de ott (1967: fig. 5, n° 1-14) 1974 (nom. nud.) chinianella zankli.glennie et al., fig. 4.4.22a-b.(oman): trias supérieur (mayhah fm) 1975 heteroporella zankli .e. flügel, pl. 2, fig. 5.nw óros tili, sw khíos / chios (grèce): rhétien-lias; pl. 4, fig. 2.hinterer gosausee, gosaukamm, dachsteingruppe, oberösterreich (autriche): norien-rhétien (dachsteinkalk) 1977 heteroporella zankli .abate et al., fig. 3 pars & 5 pars.cozzo di lupo, torretta, s carini, w palermo, sicile (italie): trias supérieur 1977 algal biolithites.abate et al., fig. 4 pars; pl. 2/7.cozzo di lupo, torretta, s carini, w palermo, sicile (italie): trias supérieur 1977 dasycladaceae .abate et al., pl. 2/7 pars.cozzo di lupo, torretta, s carini, w palermo, sicile (italie): trias supérieur 1977 heteroporella carpatica .salaj, pl. vii, fig. 5.vel’ká lúka, w tisovec, muráňska planina (slovaquie): rhétien supérieur (zone à triasina hantkeni) 1978 heteroporella zankli .e. flügel, pl. 21, fig. 5; pl. 26 pars.cozzo di lupo, torretta, s carini, w palermo, sicile (italie): trias supérieur 1979 heteroporella carpatica .bystrický, pl. v, fig. 2 & 4-5; pl. vi, fig. 4.carrière dolka, n stratená, n dobπiná, stratenská hornatina mts (slovaquie): norien (furmaneckalk); pl. v, fig. 6.carrière dolka, n stratená, n dobπiná, stratenská hornatina mts (slovaquie): norien (furmaneckalk), ou d’après bystrický (1986): norien, alaunien (h e t e r o p o r e l l a taxon-range superzone); pl. vi, fig. 5.geravy, e stratená, n dobπiná, stratenská hornatina mts (slovaquie): norien (furmaneckalk) 1979 heteroporella zankli .bystrický, pl. iv, fig. 1-5; pl. vi, fig. 8.krajcova, muráňska planina (slovaquie): norien ? supérieur (furmaneckalk); pl. iv, fig. 6.krajcova, muráňska planina (slovaquie): norien (furmaneckalk), ou d’après bystrický (1986): norien, sevatien (h e t e r o p o r e l l a taxon-range superzone); pl. v, fig. 1 & 3.geravy, e stratená, n dobπiná, stratenská hornatina mts (slovaquie): norien ? supérieur (furmaneckalk) 1979 heteroporella zankli .e. flügel, pl. 2, fig. 5.hinterer gosausee, gosaukamm, dachsteingruppe, oberösterreich (autriche): norien supérieur (dachsteinkalk) 21granier & grgasoviê: les algues dasycladales du permien et du trias... 1979 heteroporella zankli .schäfer, pl. 16, fig. 4.rötelwand, se salzburg (autriche): rhétien supérieur 1979 (?) heteroporella sp. 1.schäfer, pl. 16, fig. 3.adnet, hallein, salzburg (autriche): rhétien supérieur 1979 heteroporella zankli .senowbari-daryan & schäfer, pl. 1, fig. 8.feichtenstein, hintersee, salzburg (autriche): trias supérieur 1980b heteroporella zankli .dullo, pl. 10, fig. 6.hahnstein, sw gesäuse, steiermark (autriche): trias supérieur (dachsteinkalk) 1980 heteroporella zankli .senowbari-daryan, pl. 29, fig. 3.hintersee, salzburg (autriche): rhétien supérieur 1981b heteroporella zankly [sic].p. di stefano in catalano & d’argenio, fig. 28.b.cozzo di lupo, torretta, s carini, w palermo, sicile (italie): norien 1981 heteroporella zankli .e. flügel, fig. 10.b.feichtenstein, hintersee, salzburg (autriche): rhétien supérieur 1981 heteroporella zankli .sadati, pl. 58, fig. 4.hohe wand, niederösterreich (autriche): norien supérieur rhétien inférieur (dachsteinkalk) 1982 heteroporella zankli .e. flügel, pl. 28, fig. 5, extrait de e. flügel (1978: pl. 21, fig. 5); pl. 34 pars, extrait de e. flügel (1978: pl. 26 pars) 1982 heteroporella .senowbari-daryan et al., pl. 23, fig. 1 pars.cozzo di lupo, torretta, s carini, w palermo, sicile (italie): norien 1982 heteroporella zankli .senowbari-daryan et al., pl. 23, fig. 2.cozzo di lupo, torretta, s carini, w palermo, sicile (italie): norien 1982 heteroporella zankli .wurm, pl. 33, fig. 6.gosaukamm, dachsteingruppe, oberösterreich (autriche): norien (dachsteinkalk) 1985 heteroporella zankli .p. di stefano & senowbari-daryan, pl. iii, fig. 1-2 & 5-6.cozzo di lupo, torretta, s carini, w palermo, sicile (italie) 1986 heteroporella carpatica .bystrický, pl. vi, fig. 1, extrait de bystrický (1979: pl. v, fig. 6); pl. vi, fig. 2, extrait de bystrický (1967b: pl. xv, fig. 3) 1986 heteroporella zankli .bystrický, pl. vi, fig. 3, extrait de bystrický (1979: pl. iv, fig. 6) 1990 (?) heteroporella cf. h. zankli.lakew, pl. 49, fig. 7.albenza, nw bergamo, lombardia (italie): rhétien (calcare di zu) 1992 (?) heteroporella sp.berger & kaever, fig. 2.25.g-h.dachsteingruppe, oberösterreich (autriche): norien 1995 chinianella carpatica n. comb.granier et al., p. 132-133, non figurée 1996 chinianella zankli.bernecker, pl. 12, fig. 3.jabal kwar (oman): norien-rhétien chinianella crosi ott 1967, nom. nud. [cf. chinianella crosi (ott 1968) granier et al. 1995 ] chinianella crosi (ott 1968) granier et al. 1995 [= heteroporella crosi ott 1968, non 1967; = chinianella crosi ott 1967, nom. nud. ] 1 9 6 6 (nom. nud.) h e t e r o p o r e l l a sp.cros & lemoine, pl. 2, fig. 2.n val salata, se sénnes, nnw cortina d’ampezzo, véneto (italie): rhétien-sinémurien 1967b h e t e r o p o r e l l a sp. ind.bystrický, pl. xvi, fig. 1-3; pl. xvii, fig. 1-2.n muráňska huta, muráňs k a planina (slovaquie): ? norien terminal rhétien basal 1 9 6 7 (nom. nud.) chinianella crosi n. sp.ott, fig. 3, n° 1-6; pl. 13, fig. 1.kohlalpen-tal, kaisergebirge, tirol (autriche): rhétien-lias (rhätolias-riffkalk).holotype: pl. 13, fig. 1, lame mince n° g 646 a/67, collection e. ott, bayerische staatssammlung für paläontologie und historische geologie, münchen (allemagne) 1968 heteroporella crosi n. comb.ott, p. 258, non figurée 1972 heteroporella crossi [s i c].fenninger & holzer, pl. 12, fig. 2.sparber, strobl, salzburg (autriche): trias supérieur 1975 heteroporella crosi .e. flügel, pl. 4, fig. 7.nw óros tili, sw khíos / chios (grèce): trias supérieur 1978 heteroporella crosi .e. flügel, pl. 26 pars.cozzo di lupo, torretta, s carini, w palermo, sicile (italie): trias supérieur 22 geologia croatica 53/1 1982 heteroporella crosi .e. flügel, pl. 34 pars, extrait de e. flügel (1978: pl. 26 pars) 1995 chinianella crosi n. comb.granier et al., p. 133-134, non figurée chinianella macropora (p. di stefano ex p. di stefano et senowbari-daryan 1985) granier et al. 1995 [= heteroporella macropora p. di stefano ex p. di stefano et senowbari-daryan 1985 ] 1978 (?) heteroporella .e. flügel, pl. 9.11.bad aussee, salzkammergut, steiermark (autriche): trias supérieur (dachsteinkalk) 1981b (nom. nud.) heteroporella macropora .p. di stefano in catalano & d’argenio, fig. 28.d.cozzo di lupo, torretta, s carini, w palermo, sicile (italie): norien.type non désigné 1982 (?) heteroporella .e. flügel, pl. 10.11, extrait de e. flügel (1978: pl. 9.11) 1985 heteroporella macropora n. sp.p. di stefano & senowbari-daryan, fig. 8; pl. i, fig. 1-8.cozzo di lupo, torretta, s carini, w palermo, sicile (italie): norien.validation de l’espèce; holotype: pl. i, fig. 1, lame mince n° si 26.b, coll. a 59, museo di geologia dell’università di palermo (italie) 1995 chinianella macropora n. comb.granier et al., p. 134, non figurée chinianella micropora (p. di stefano ex p. di stefano et senowbari-daryan 1985) granier et al. 1995 [= heteroporella micropora p. di stefano ex p. di stefano et senowbari-daryan 1985 ] 1981b (nom. nud.) heteroporella micropora .p. di stefano in catalano & d’argenio, fig. 28.e.cozzo di lupo, torretta, s carini, w palermo, sicile (italie): norien.type non désigné 1985 heteroporella micropora n. sp.p. di stefano & senowbari-daryan, fig. 7 pars & 9-10; pl. ii, fig. 1-9.cozzo di lupo, torretta, s carini, w palermo, sicile (italie): norien.holotype: pl. ii, fig. 1, lame mince n° si 24.a, coll. a 66, museo di geologia dell’università di palermo (italie) 1995 chinianella micropora n. comb.granier et al., p. 134, non figurée chinianella zankli ott 1967, nom. nud. [“synonyme” de chinianella carpatica (bystrický 1967) granier et al. 1995 ] clavaphysoporella endo 1958, emend. güvenç 1979 [synomyme postérieur de physoporella steinmann 1903, emend. pia 1912, d’après kochansky & herak, 1960 ] clavaphysoporella americana johnson et kaska 1965, nom. nud. [cf. clavaporella americana (johnson et kaska 1965) vachard 1980, nom. nud. ] clavaphysoporella annulata endo 1969 [cf. clavaporella annulata (endo 1969) vachard 1980 ] clavaphysoporella asiatica endo 1969 [cf. clavaporella asiatica (endo 1969) vachard 1980 ] clavaphysoporella compacta endo 1969, nom. nud. 1968b (nom. nud.) clavaphysoporella compacta n. sp.endo, “chart”, non figurée.type non figuré 1969 (nom. nud.) clavaphysoporella compacta n. sp.endo, p. 35-37, non figurée.type non figuré clavaphysoporella conforma endo 1958, nom. nud. [cf. clavaporella conforma (endo 1958) kochansky et herak 1960, nom. nud. ] 23granier & grgasoviê: les algues dasycladales du permien et du trias... clavaphysorella elegantannulata (endo in endo et kanuma 1954) endo 1959 [cf. clavaporella elegantannulata (endo in endo et kanuma 1954) kochansky et herak 1960 ] clavaphysoporella faceta endo 1958, nom. nud. [cf. clavaporella faceta (endo 1958) kochansky et herak 1960, nom. nud. ] clavaphysoporella ? fluctuosa endo 1958, nom. nud. 1958 (nom. nud.) clavaphysoporella fluctuosa n. sp.endo, pl. 39, fig. 8-9.hatahoko, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien (gonbō fm, nyūgawa group).“holotype” (syntypes): pl. 39, fig. 8-9, lame mince n° 21044, geol. min. inst., tokyo kyoiku daigaku [tokyo university of education ] (japon) 1959 (nom. nud.) clavaphysoporella fluctuosa .endo, pl. 38, fig. 11 & 13, extrait de endo (1958: pl. 39, fig. 8-9); pl. 38, fig. 12.hatahoko, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien inférieur (gonbō fm, zone à pseudoschwagerina ) 1961a (nom. nud.) clavaphysoporella fluctuosa .endo, pl. 3, fig. 7, extrait de endo (1958: pl. 39, fig. 8) 1963 (nom. nud.) clavaphysoporella fluctuosa .johnson, pl. 53, fig. 1, extrait de endo (1958: pl. 39, fig. 8) clavaphysoporella ? gigas endo 1961, nom. nud. 1961b (nom. nud.) clavaphysoporella gigas n. sp.endo, pl. 15, fig. 2-3.e o _ nogi, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien “moyen” / partie inférieure (o _ nogi fm); pl. 15, fig. 4.w nagaoka, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 16, fig. 2.e o _ nogi, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien “moyen” / partie inférieure (o _ nogi fm).“holotype” (syntypes): pl. 15, fig. 2, lame mince n° 0529-12; pl. 15, fig. 4, lame mince n° 510606-d, geological survey of japan (japon) clavaphysoporella ? grandipora endo 1969, non 1968 1968b (nom. nud.) clavaphysoporella grandipora n. sp.endo, “chart”, non figurée.type non figuré 1969 clavaphysoporella grandipora n. sp.endo, pl. xxxi, fig. 1-8.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancel l i n a ).holotype: pl. xxxi, fig. 1, lame mince n° gk.d 13046, kyū s hū university, fukuoka (japon) clavaphysoporella ? kittakai nakamura et chisaka 1984, nom. nud. 1 9 8 4 (nom. nud.) clavaphysoporella kittakai n. sp.nakamura & chisaka, pl. 9, fig. 1-12.mt atagoyama, chôshi-shi, chiba-ken, honshū (japon): permien “supérieur” (takagami conglomerate).syntypes: pl. 9, fig. 1, lame mince n° nsm-pp 7904b; pl. 9, fig. 2, lame mince n° nsm-pp 7903g; pl. 9, fig. 12, lame mince n° nsm-pp 7906a, national science museum, tokyo (japon) clavaphysoporella longiclava endo 1968, nom. nud. 1968b (nom. nud.) clavaphysoporella longiclava n. sp.endo, “chart”, non figurée.type non figuré clavaphysoporella mina endo 1959, nom. nud. 1959 (nom. nud.) clavaphysoporella mina n. sp.endo, p. 179, non figurée.type non figuré *clavaphysoporella minutula (gümbel 1872) endo 1958 [cf. physoporella minutula (gümbel 1872) pia 1912 ] clavaphysoporella ? nanus endo 1959, nom. nud. 1 9 5 9 (nom. nud.) clavaphysoporella nanus n. sp.endo, pl. 38, fig. 14-15.otani, horadani valley, nyūg a w a mura, o _ no-gun, gifu-ken, honshū (japon): permien inférieur (o _ zu fm, zone à pseudofusulina).“holo type” (syntypes): pl. 38, fig. 14, lame mince n° 21128; pl. 38, fig. 15, lame mince n° 21048, geol. min. inst., tokyo kyoiku daigaku [tokyo university of education ] (japon) 24 geologia croatica 53/1 clavaphysoporella ? pteroides endo 1961, nom. nud. 1961b (nom. nud.) clavaphysoporella pteroides n. sp.endo, pl. 13, fig. 4; pl. 14, fig. 6-7.sukawa, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 14, fig. 8; pl. 18, fig. 3.e o _ nogi, santō -machi, sakata-gun, shiga-ken, honshū (japon): permien “moyen” / partie inférieure (o _ nogi fm).“holotypes” (syntypes): pl. 14, fig. 8; pl. 18, fig. 3, lame mince n° 510529-12, geologi cal survey of japan (japon) clavaphysoporella ? shigensis endo 1961, nom. nud. 1961b (nom. nud.) clavaphysoporella shigensis n. sp.endo, pl. 15, fig. 6.n manganji, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 16, fig. 3.sukawa, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm).type non figuré, “holotype”: lame mince n° 510606-b, geological survey of japan (japon) clavaphysoporella similis endo 1959, nom. nud. [cf. clavaporella similis (endo 1959) vachard 1980, nom. nud. ] clavapora güvenç 1979 *clavapora clavaeformis (pia 1920) güvenç 1979 [= diplopora clavaeformis pia 1920 ] 1920 diplopora clavaeformis n. sp.pia, pl. iv, fig. 17.bare, zli stup, han bulog, sarajevo (bosnie-herzégovine): anisien (couches à t r i n o d o s u s).type: pl. iv, fig. 17, lame mince n° ?, collection j. von pia, naturhistorisches museum, wien (autriche) fig. 4 diplopora clavaeformis (soka», 1974, pl. iii, fig. 4), x5.5. fig. 5 diplopora clavaeformis (soka», 1974, pl. iii, fig. 1), x5.5. 25granier & grgasoviê: les algues dasycladales du permien et du trias... 1974 diplopora clavaeformis .sokaë, pl. i, fig. 1-4; pl. ii, fig. 1-3; pl. iii, fig. 1-5; pl. iv, fig. 1-3; pl. v, fig. 1-4.w rastovaëa, graëac, velebit mt (croatie): ladinien inférieur 1979 clavapora clavaeformis n. gen. n. comb.güvenç, p. 631, non figurée 1982 diplopora clavaeformis .bystrický, pl. 1, fig. 1-4; pl. 4, fig. 2 pars.slatinka nad bebravou ©ípkov, stráæovské vrchy, e trencín (slovaquie): anisien-ladinien, ou d’après bystrický (1986): ladinien, fassanien (diplopora annulata taxon-range zone) 1986 diplopora clavaeformis .bystrický, pl. iv, fig. 3, extrait de bystrický (1982: pl. 1, fig. 1) clavaporella kochansky et herak 1960, emend. vachard 1980 clavaporella americana (johnson et kaska 1965) vachard 1980, nom. nud. [= clavaphysoporella americana johnson et kaska 1965, nom. nud. ] 1965 (nom. nud.) clavaphysoporella americana n. sp.johnson & kaska, pl. 2, fig. 2-6.? san luis (guatemala): permien “moyen”.“the type” (syntypes): pl. 2, fig. 2, recélant plusieurs spécimens, “type slide 8333(2)”, collection j.h. johnson, = u.s. national museum no. 042506, smithsonian institution, washington (états-unis d’amérique) 1980 (nom. nud.) clavaporella americana n. comb.vachard, p. 363, non figurée 1 9 9 7 (nom. nud.) clavaporella americana .vachard & fourcade, fig. 12.30-35 & 12.37-38.suquinay, purulhà, baja verapaz (guatemala): bolorien (fm chócal, chócal de suquinay) clavaporella annulata (endo 1969) vachard 1980 [= clavaphysoporella annulata endo 1969 ] 1969 clavaphysoporella annulata n. sp.endo, pl. xxxiv, fig. 6.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancelli n a).holotype: pl. xxxiv, fig. 6, lame mince n° gk.d 13287, kyū s hū university, fukuoka (japon) 1980 clavaporella annulata n. comb.vachard, p. 363, non figurée clavaporella asiatica (endo 1969) vachard 1980 [= clavaphysoporella asiatica endo 1969] 1969 clavaphysoporella asiatica n. sp.endo, pl. xxxii, fig. 8-11; pl. xxxiii, fig. 1-3 & 9.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à c a n c e l l i n a ).holotype: pl. xxxiii, fig. 1, lame mince n° gk.d 13016, kyū s hū university, fukuoka (japon) 1980 clavaporella asiatica n. comb.vachard, p. 363, non figurée clavaporella baxoensis mu 1982 1982 clavaporella baxoensis n. sp.mu, pl. ix, fig. 6-9 & 13.xizang / tibet (chine populaire): permien “inférieur” / partie supérieure.holotype: pl. ix, fig. 6, lame mince n° pb8070, nanjing institute of geology and paleontology, academia sinica, nanjing (chine populaire) *clavaporella caliciformis kochansky et herak 1960 1960 clavaporella caliciformis n. gen. n. sp.kochansky & herak, pl. viii, fig. 1-9.matkoviê, nw bar, s monténégro (yougoslavie): léonardien supérieur wordien inférieur (galets dans un conglomérat a n i s i e n ).holotype: pl. viii, fig. 5, lame mince n° 1501, collection v. kochansky-devidé, geoloπko-paleontoloπki zavod, prirodoslovno-matematiëki fakultet [geological and palaeontological institute, faculty of sciences ], zagreb (croatie) 1963 clavaporella calciformis [sic].johnson; pl. 51, fig. 1-9, extrait de kochansky & herak (1960: pl. viii, fig. 1-9) 1963 (?) clavaporella sp.pantiê, pl. x, fig. 4.sw haj nehaj, miπiêi, kotor, monténégro (yougoslavie): permien “supérieur” (galet dans un conglomérat anisien) 26 geologia croatica 53/1 1965 clavaphysoporella caliciformis [s i c].kordé, pl. lviii, fig. 1-2.avush, nakhichevan’ (azerbaïdjan): guadalupien 1977 (?) clavaphysoporella sp.e. flügel, pl. pl. 3/4 pars.velebit mt (croatie): permien “moyen” 1978 clavaporella caliciformis .anelkoviê, pl. xl, fig. 3 = pl. xli, fig. 1, extrait de kochansky & herak (1960: pl. viii, fig. 8); pl. xli, fig. 2, extrait de kochansky & herak (1960: pl. viii, fig. 9); pl. xli, fig. 3, extrait de kochansky & herak (1960: pl. viii, fig. 5); pl. xli, fig. 4, extrait de kochansky & herak (1960: pl. viii, fig. 6) 1980 clavaporella caliciformis .vachard, pl. 24, fig. 10.tezak khwaja bahadur, tezak (afghanistan): kubergandien 1981 clavaporella caliciformis .rauzer-chernousova & korolyuk, pl. iii, fig. 11-16; pl. iv, fig. 1-3.s oural (fédération de russie): carbonifère, silésien, moscovien supérieur 1981 clavaporella caliciformis .vachard in vachard & montenat, pl. 4, fig. 11.khwaja bahadur, tezak (afghanistan): murghabien supérieur; pl. 5, fig. 8, extrait de vachard (1980: pl. 24, fig. 10); pl. 5, fig. 14.khwaja bahadur, tezak (afghanistan): murghabien inférieur 1989 clavaporella caliciformis .nguyên, pl. 23, fig. 5 & 10.bukit pendopo, s sumatra (indonésie): murghabien 1993 clavaporella caliciformis .vachard et al., pl. i, fig. 7.s ermióni, argolís (grèce): djulfien (galet dans une “coulée boueuse” kimméridgienne de la fm de potami) fig. 6 clavaporella caliciformis (kochansky & herak, 1960, pl. viii, fig. 3), x33. fig. 7 clavaporella caliciformis (kochansky & herak, 1960, pl. viii, fig. 5), x66. 27granier & grgasoviê: les algues dasycladales du permien et du trias... clavaporella conforma (endo 1958) kochansky et herak 1960, nom. nud. [= clavaphysoporella conforma endo 1958, nom. nud. ] 1 9 5 8 (nom. nud.) clavaphysoporella conforma n. sp.endo, pl. 39, fig. 6-7.otani, horadani valley, nyūg a w a mura, o _ no-gun, gifu-ken, honshū (japon): permien (o _ zu fm, nyūgawa group).“holotype” (syntypes): pl. 39, fig. 6-7, lame mince n° 21048, geol. min. inst., tokyo kyoiku daigaku [tokyo uni versity of education ] (japon) 1959 (nom. nud.) clavaphysoporella conforma .endo, pl. 38, fig. 8-9, extrait de endo (1958: pl. 39, fig. 6-7) 1959 clavaphysoporella sp.endo, pl. 38, fig. 10.otani, horadani valley, nyūgawa-mura, o _ no-gun, gifuken, honshū (japon): permien (o _ zu fm, nyūgawa group) 1960 (nom. nud.) clavaporella conforma n. comb.kochansky & herak, p. 87, non figurée 1961b (nom. nud.) clavaphysoporella conforma .endo, pl. 13, fig. 1.muraki, ibuki-mura, santō-machi, sakatagun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 13, fig. 2.w hongō, santōmachi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 13, fig. 3.iwakurayama, sekigahara-machi, fuwa-gun, gifu-ken, honshū (japon): permien “moyen” / partie inférieure (ibukiyama limestone fm / partie inférieure); pl. 14, fig. 4-5.e o _ nogi, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien “moyen” / partie inférieure (o _ nogi fm) clavaporella elegantannulata (endo in endo et kanuma 1954) kochansky et herak 1960 [= clavaphysoporella elegantannulata (endo in endo et kanuma 1954) endo 1959; = physoporella elegantannulata endo in endo et kanuma 1954 ] 1954 physoporella elegantannulata n. sp.endo in endo & kanuma, pl. xvii, fig. 3-6.kamikowa, suwaramura, mugi-gun, gifu-ken, honshū (japon): permien inférieur-moyen (kuchibora fm, zone à p s e u d o fusulina zone à parafusulina ).“holotype”: non figuré, lame mince n° 185; “paratype” (syntypes): pl. xvii, fig. 4-5, lame mince n° 209, department of earth sciences, saitama university, urawa (japon) 1959 clavaphysoporella elegantannulata n. comb.endo, pl. 37, fig. 5.yokoberadani valley, hatahoko, n yūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien moyen (o _ zu fm, zone à n e o s c h w a g e r i n a); pl. 37, fig. 6.chôshidani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien (o _ zu fm); pl. 40, fig. 6-7.otani, horadani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien inférieur (o _ zu fm, zone à pseudofusulina) 1960 clavaporella elegantannulata n. comb.kochansky & herak, p. 87, non figurée 1961b clavaphysoporella elegantannulata .endo, pl. 12, fig. 8.muraki, ibuki-mura, santō-machi, sakatagun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 12, fig. 9.e o _ nogi, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien “moyen” / partie inférieure (o _ nogi fm); pl. 12, fig. 10.n manganji, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 14, fig. 3.sukawa, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm) 1968b clavaphysoporella elegantannulata .endo, pl. ii, fig. 1.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien 1969 (?) clavaphysoporella cf. elegantannulata .endo, pl. xxxii, fig. 1-7.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina ) clavaporella faceta (endo 1958) kochansky et herak 1960, nom. nud. [= clavaphysoporella faceta endo 1958, nom. nud. ] 1 9 5 8 (nom. nud.) clavaphysoporella faceta n. sp.endo, pl. 39, fig. 1 & 4-5.sotedani valley, nyūg a w a m u r a , o _ no-gun, gifu-ken, honshū (japon): permien (nyūgawa group, o _ zu fm & gonbō fm); pl. 39, fig. 2-3.horadani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien (nyūgawa group, o _ z u fm & gonbō f m ).“holotype” (syntypes): pl. 39, fig. 1, lame mince n° 606; pl. 39, fig. 5, lame mince n° 607; paratype: pl. 39, fig. 4, lame mince n° 21049; “paratypes”: pl. 39, fig. 2, lame mince n° 609, department of earth sciences, saitama university, urawa (japon); pl. 39, fig. 3, lame mince n° 21055, geol. min. inst., tokyo kyoiku daigaku [tokyo university of education ] (japon) 1959 (nom. nud.) clavaphysoporella faceta .endo, pl. 37, fig. 9, extrait de endo (1958: pl. 39, fig. 3); pl. 37, fig. 13; pl. 38, fig. 3.otani, horadani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien 28 geologia croatica 53/1 inférieur (o _ zu fm, zone à p s e u d o f u s u l i n a); pl. 37, fig. 10, extrait de endo (1958: pl. 39, fig. 2); pl. 37, fig. 11-12; pl. 38, fig. 1-2.chôshidani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien (o _ zu fm); pl. 41, fig. 1, extrait de endo (1958: pl. 39, fig. 1); pl. 41, fig. 3, extrait de endo (1958: pl. 39, fig. 4); pl. 41, fig. 2 & 4-6.sotedani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien inférieur-moyen (o _ zu fm, zone à parafusulina / partie supérieure) 1960 (nom. nud.) clavaporella faceta n. comb.kochansky & herak, p. 87, non figurée 1961b (?) (nom. nud.) clavaphysoporella cf. faceta .endo, pl. 15, fig. 5.e o _ nogi, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien “moyen” / partie inférieure (o _ nogi fm) 1 9 6 1 (nom. nud.) clavaphysoporella faceta .johnson, pl. 55, fig. 1, extrait de endo (1958: pl. 39, fig. 4); pl. 55, fig. 2, extrait de endo (1958: pl. 39, fig. 1) 1 9 6 3 (nom. nud.) clavaphysoporella faceta .johnson, pl. 52, fig. 1, extrait de endo (1958: pl. 39, fig. 3); pl. 52, fig. 2, extrait de endo (1958: pl. 39, fig. 1); pl. 52, fig. 3, extrait de endo (1959: pl. 37, fig. 13); pl. 52, fig. 4, extrait de endo (1959: pl. 37, fig. 12); pl. 52, fig. 5, extrait de endo (1959: pl. 37, fig. 11); pl. 52, fig. 6, extrait de endo (1958: pl. 39, fig. 2); pl. 52, fig. 7, extrait de endo (1958: pl. 39, fig. 4) 1 9 6 8 b (nom. nud.) clavaphysoporella facefa [s i c].endo, pl. i, fig. 6.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien 1969 (nom. nud.) clavaphysoporella faceta .endo, pl. xxvii, fig. 9; pl. xxviii, fig. 1-4; pl. xxix, fig. 1-5; pl. xxx, fig. 1-8.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien inférieur-moyen (rat buri limestone, zone à misellina zone à cancellina ) 1990 (nom. nud.) clavaporella faceta .e. flügel, pl. 2, fig. 3-4.w koca-dag, n bergama (turquie): murghabien moyen (zone à neoschwagerina craticulifera ); pl. 3, fig. 2 pars & 3 pars.kapiskaya, ne kinik, sse balya (turquie): murghabien (zone à neoschwagerina / partie moyenne) 1 9 9 3 (nom. nud.) clavaporella c f . f a c e t a e [s i c].dawson, pl. 9, fig. 4-5 & 7.n sara buri, n krung thep / bangkok (thaïlande): yahtashien-bolorien (rat buri limestone) clavaporella kochanskae milanovi∆ ex vachard 1980 [= salopekiella ? kochanskae milanovi∆ 1968, nom. nud. ] 1 9 6 8 (nom. nud.) salopekiella ( ? ) k o c h a n s k a e n. sp.milanoviê, pl. i, fig. 1-6; pl. ii, fig. 1-6; pl. iii, fig. 1-6; pl. iv, fig. 1-6.veliki beπlinac, brezik, medak, velebit mt (croatie): artinskien supérieur kazanien i n f é r i e u r.holotype: pl. i, fig. 3, lame mince n° br.-8b/3 (texte) ou u-4012/5 (légende de la figure), collection m. milanoviê, institut za geoloπka istraæivanja [institute of geology ], zagreb (croatie) 1980 clavaporella kochanskyae n. comb. [s i c].vachard, p. 363-364 & 367, non figurée.validation de l’espèce 1985 clavaporella kochanskae .vachard, pl. 1, fig. 4 pars & 6-7.djebel tebaga (tunisie): murghabien supérieur 1992 (?) clavaporella c f . k o c h a n s k a e.vachard et al., pl. iii, fig. 9 pars.n ban na wai, nw thaïlande (thaïlande): murghabien supérieur midien 1993 clavaporella kochanskae .vachard & razgallah, pl. 1, fig. 5 pars.djebel tebaga (tunisie): murghabien supérieur (zone à neoschwagerina, yabeina et dunbarula , sous-zone à dunbarula nana ) clavaporella media vachard 1980, nom. nud. [cf. eovelebitella media vachard in vachard et montenat 1981 ] clavaporella orientalis (endo 1961) vachard 1980 [= amicus orientalis endo 1961 ] 1961b amicus orientalis n. sp.endo, pl. 18, fig. 6.e o _ nogi, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien “moyen” / partie inférieure (o _ nogi fm).holotype: pl. 18, fig. 6, lame mince n° 510529-2 (ou 510529-12), geological survey of japan (japon) 1980 clavaporella orientalis n. comb.vachard, p. 363, non figurée clavaporella pusilla (kochansky et herak 1960) vachard 1980 [cf. eovelebitella pusilla (kochansky et herak 1960) vachard 1974 ] 29granier & grgasoviê: les algues dasycladales du permien et du trias... clavaporella similis (endo 1959) vachard 1980, nom. nud. [= clavaphysoporella similis endo 1959, nom. nud. ] 1 9 5 9 (nom. nud.) clavaphysoporella similis n. sp.endo, pl. 38, fig. 4-5.hatahoko, nyūgawa-mura, o _ n o g u n , gifu-ken, honshū (japon): permien (gonbō fm, zone à p a r a f u s u l i n a = zone à p s e u d o s c h w a g e r i n a [s i c]); pl. 38, fig. 6.sotedani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien moyen (o _ zu fm, zone à n e o s c h w a g e r i n a / partie inférieure); pl. 38, fig. 7.hatahoko, nyūg a w a m u r a , o _ no-gun, gifu-ken, honshū (japon): permien inférieur (gonbō fm, zone à p s e u d o s c h w a g e r i n a / partie s u p é r i e u r e ).“holotype” (syntypes): pl. 38, fig. 4-5, lame mince n° 21135a, geol. min. inst., tokyo kyoiku daigaku [tokyo university of education ] (japon) 1961b (nom. nud.) clavaphysoporella similis.endo, pl. 14, fig. 2.e o _ nogi, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien “moyen” / partie inférieure (o _ nogi fm) 1980 (nom. nud.) clavaporella similis n. comb.vachard, p. 363, non figurée clypeina michelin 1845, emend. bassoullet et al. 1978 clypeina besici panti∆ in granier et deloffre 1995, non 1965 1 9 6 5 (nom. nud.) clypeina beπiêi n. sp.pantiê, pl. i, fig. 1-6; pl. ii, fig. 1-7.–inovo brdo, cetinje, monténégro (yougoslavie): carnien; pl. iii, fig. 1-6; pl. iv, fig. 1-2; pl. v, fig. 4-5.bjeloπi, cetinje, monténégro (yougoslavie): carnien; pl. v, fig. 1-3.ruisseau jazina, trebinje (bosnie-herzégovine): carnien.syn types: pl. i, fig. 1, lame mince n° 2098-61; pl. i, fig. 2, lame mince n° 2096-61; pl. i, fig. 3 & pl. ii, fig. 2, lame mince n° 2104-61; pl. i, fig. 4 & 6 & pl. ii, fig. 1, lame mince n° 2111-61; pl. i, fig. 5, lame mince n° 2100-61; pl. ii, fig. 4, lame mince n° 1580-59; pl. ii, fig. 3, lame mince n° 2105-61; pl. ii, fig. 5, lame mince n° 2095-61; pl. ii, fig. 6, lame mince n° 2103-61; pl. ii, fig. 7, lame mince n° 2110-61, collection s. pantiê, zavod za geoloπka i geofiziëka istraæivanja beograd [institut de recherches géologiques et géophysiques ], belgrade (yougoslavie) 1967 (?) clypeina sp.holzer, pl. 1, fig. 1-2 & 8 pars.s klaus an der pyhrnbahn, steyrtal, oberösterreich (autriche): carnien, cordevolien (wettersteinkalk) 1967 (nom. nud.) clypeina beπiêi.pantiê, pl. vii, fig. 1-3.lepa glava, tara mt, w serbie (yougoslavie): carnien 1 9 6 8 (nom. nud.) ? clypeina besici.–uranoviê, pl. i, fig. 9.sw vojsko, idrija gornja trebuπa (slovénie): carnien 1 9 7 2 non (nom. nud.) clypeina besici.»anoviê & kemenci, pl. iii, fig. 7 (= “genus ?”, pl. xxix, fig. 2 in »anoviê & kemenci, 1988).forage senta 1 (st-1), w senta, vojvodina, serbie (yougoslavie): carnien 1972 (nom. nud.) clypeina besici.»anoviê & kemenci, pl. iii, fig. 8.forage senta 1 (st-1), w senta, vojvodina, serbie (yougoslavie): carnien 1972 dasycladacea.kodra, pl. 3, fig. 8.prozhmë, kollatë, valbona (albanie): norien-rhétien (suita e prozhmë) 1 9 7 2 a (nom. nud.) c l y p e i n a cf. b e s i c i.ott, fig. 2.1.raibler bandes, müllnerhorn, reichenhall, bayern (allemagne): carnien (ramsaudolomit); fig. 2.2-13.s kaisergebirge, tirol (autriche): carnien, cordevolien (obersten wettersteinkalk) 1972b (nom. nud.) clypeina beπiêi.pantiê, pl. v, fig. 1.ovëar banja, w serbie (yougoslavie): carnien 1 9 7 2 (nom. nud.) clypeina besici.pantiê & rampnoux, pl. ii, fig. 4.kostam polje, golija zone, serbie (yougoslavie): carnien 1972 (nom. nud.) clypeina besici.ramovπ, pl. ii, fig. 4 pars.turnce, nw ljubljana (slovénie): carnien, julien 1 9 7 4 (nom. nud.) clypeina besici.pantiê, pl. v, fig. 1-2.ruisseau ljubeniê, prokletije mts, kosovo, serbie (yougoslavie): carnien 1 9 7 5 (nom. nud.) clypeina besici.pantiê-prodanoviê, pl. lxxi, fig. 1-2.bjeloπi, cetinje, monténégro (yougoslavie): carnien; pl. lxxii, fig. 1.cetinje, monténégro (yougoslavie): carnien 1977 (?) clypeina sp.flajs, pl. 17, fig. 6.trentino alto adige (italie): trias supérieur (cassianer schichten) 1978 clypeina.e. flügel, pl. 25 pars.amtmanngalgen, johnsbach, gesäuse, steiermark (autriche): ladinien (wettersteinkalk) 1 9 7 8 non (nom. nud.) clypeina besici.trifonova, pl. v, fig. 9.forage r-115, bǎlgarevo (bulgarie): ladinien, langobardien terminal (belimel fm, glomospira densa / turritella mesotriassica interval-zone) 30 geologia croatica 53/1 1980 (?) (nom. nud.) clypeina besici.dragastan, fig. 103.valea morilor, pestis (roumanie): carnien 1 9 8 0 a non (nom. nud.) clypeina besici.dullo, pl. 1, fig. 2.sw gesäuse, steiermark (autriche): carnien (tisoveckalk) 1 9 8 1 (?) (nom. nud.) c l y p e i n a sp. cf. c. besici.bradner & resch, fig. 24.c.dobratsch, w villach, kärnten (autriche): carnien, cordevolien (wettersteinkalk) 1982 clypeina.e. flügel, pl. 33 pars, extrait de e. flügel (1978: pl. 25 pars) 1982 (nom. nud.) clypeina besici.henrich, pl. 13, fig. 7.2.scharnkopf, hochstaufen-zwieselmassif, w salzburg, bayern (allemagne): carnien, cordevolien (wettersteinkalk) 1983 (?) clypeina sp.schäfer & senowbari-daryan, pl. 6, fig. 6.ídhra / hydra (grèce): trias supérieur 1 9 8 4 (nom. nud.) clypeina besici.henrich, pl. 9, fig. 6.2.extrait de henrich (1982: pl. 13, fig. 7.2); pl. 15, fig. 1.2.rauschberg, hochstaufen zwieselmassif, w salzburg, bayern (allemagne): carnien, cordevolien (wettersteinkalk) 1984 non (nom. nud.) clypeina besici.ogorelec et al., pl. 9, fig. 3 pars & 4 pars.izvir nadize, tamar, w vrπië, w kranjska gora (slovénie): carnien, julien-tuvalien 1988 (?) (nom. nud.) ? clypeina besici.»anoviê & kemenci, pl. xxviii, fig. 1-2.forage senta 1 (st-1), w senta, vojvodina, serbie (yougoslavie): norien-rhétien 1995 clypeina besici.pantiê in granier & deloffre, p. 57, non figurée.typification et validation de l’espèce; lectotype: pl. i, fig. 1 in pantiê (1965), lame mince n° 2098-61, collection s. pantiê, zavod za geoloπka i geofiziëka istraæivanja beograd [institut de recherches géologiques et géophysiques ], belgrade (yougoslavie) 1997 clypeina besici.grgasoviê, pl. ii, fig. 2, 4-7, 11-12 & 16-19.æumberak mt, ne kraπiê, w zagreb (croatie): carnien (slapnica fm, clypeina besici taxon-range zone) connexia kochansky-devidé 1970 connexia carniapulchra e. flügel et flügel-kahler 1980 [synonyme postérieur de connexia slovenica kochansky-devidé 1979, d’après vachard, 1989 ] connexia slovenica kochansky-devidé 1979 1965 dasycladaceae n. gen. n. sp.kochansky-devidé & ramovπ, pl. xi, fig. 1.ortnek (slovénie): permien 1970a teutloporella n. sp.kochansky-devidé, pl. xxii, fig. 5-6.w karavanke (slovénie): permien inférieur (trogkofelkalk) 1972 (nom. nud.) likanella ? cf. l. spinosa.homann, pl. 6, fig. 44.nw zottach-kogel, kärnten (autriche): sakmarien (trogkofelkalk) 1979 connexia slovenica n. sp.kochansky-devidé, pl. i, fig. 1.ortnek, n hojëe, dolenjsko (slovénie): permien inférieur (trogkofelkalk); pl. i, fig. 2-5; pl. ii, fig. 3.forage, karavanke (slovénie): permien inférieur (trogkofelkalk); pl. i, fig. 6; pl. ii, fig. 1-2.julijske alpe (slovénie): permien inférieur (trogkofelkalk).holotype: pl. i, fig. 1, lame mince n° 16a/3, collection v. kochansky-devidé, kat edra za geologijo in paleontologijo univerze v ljubljani [sammlung des lehrkanzel für geologie und paläontologie der universität in ljubljana ], ljubljana (slovénie) 1980 connexia carniapulchra n. sp.e. flügel & flügel-kahler, pl. 3, fig. 1-3 & 5.e treßdorfer höhe nw naßfeld-paß / passo di pramollo, kärnten (autriche): permien inférieur (unterer pseudoschwagerinenkalk); pl. 3, fig. 4 & 7.ne col mezzodì, forni avoltri, friuli venezia giulia (italie): permien inférieur (kalkbrekzie); pl. 3, fig. 6.ne col mezzodì, forni avoltri, friuli venezia giulia (italie): permien inférieur (trogkofelkalk); pl. 3, fig. 8.reppwand-gartnerkofel, s hermagor, kärnten (autriche): permien inférieur (trogkofelkalk).holotype: pl. 3, fig. 1, lame mince n° 3066, collection e. flügel & flügel-kahler, botan.-paläobotanische abteilung, senckenberg-museum, frankfurt am main (allemagne) 1980 connexia carniapulchra .e. flügel, pl. 8, fig. 4.forni avoltri, friuli venezia giulia (italie): permien inférieur (brekzie) 1982 connexia carniapulchra .e. flügel, “cover”.dolomiti di sesto / sextener dolomiten, trentino alto adige (italie): artinskien inférieur (galet dans la tarvis breccia) 31granier & grgasoviê: les algues dasycladales du permien et du trias... 1982 dasycladaceae ind.mu, pl. vi, fig. 11-13.xizang / tibet (chine populaire): carbonifère, silésien 1988 (?) c o n n e x i a.e. flügel & kraus, pl. 1, fig. 6 pars.e san cándido / innichen, valle di sesto / sextental, trentino alto adige (italie): permien inférieur (sexten breccia) 1988a (sans légende).lys, pl. iv, fig. 1 pars.forage kirchaou 1 (kr-1), foum tatatouine ben gardane, s gabes (tunisie): assélien moyen, partie supérieure 1989 connexia slovenica.vachard, pl. 7, fig. 3-6; pl. 9, fig. 2 pars & 3.pulau apat, jambi province, sumatra (indonésie): assélien moyen-sakmarien (assélien supérieur probable) 1991 (?) connexia sp.e. flügel et al., pl. 47, fig. 4 pars.pietra di salomone, sw palazzo adriano, sw prizzi, sicile (italie): permien 1997 connexia slovenica.vachard & fourcade, fig. 12.18-26.finca santa maria, presa de chixoy, alta verapaz (guatemala): léonardien moyen (fm chócal, chócal de purulhà) diplopora schafhäutl 1863, emend. güvenç 1979 diplopora adnetensis e. flügel 1975 1975 diplopora adnetensis n. sp.e. flügel, pl. 2, fig. 6; pl. 3, fig. 1-4.adnet, hallein, salzburg (autriche): rhétien supérieur.holotype: pl. 3, fig. 4, lame mince n° fl 01, collection e. flügel, botan.-paläob otanische abteilung, senckenberg-museum, frankfurt am main (allemagne) 1978 diplopora adnetensis .e. flügel, pl. 24, fig. 4.gruber, feichtenstein, hintersee, salzburg (autriche): rhétien supérieur 1979 diplopora adnetensis .schäfer, pl. 16, fig. 1.adnet, hallein, salzburg (autriche): rhétien supérieur 1979 diplopora adnetensis .senowbari-daryan & schäfer, pl. 1, fig. 10.adnet, hallein, salzburg (autriche): trias supérieur 1980 diplopora adnetensis .senowbari-daryan, pl. 12, fig. 7.gruber, feichtenstein, hintersee, salzburg (autriche): rhétien supérieur 1981b diplopora adnetensis .p. di stefano in catalano & d’argenio, fig. 28.g.cozzo di lupo, torretta, s carini, w palermo, sicile (italie): norien 1981 diplopora adnetensis .e. flügel, fig. 10.a.adnet, hallein, salzburg (autriche): rhétien supérieur 1982 diplopora adnetensis .senowbari-daryan et al., pl. 23, fig. 4 pars.mte pellegrino, s mondello n palermo, sicile (italie): norien 1982 (?) diplopora adnetensis .wurm, pl. 38, fig. 7.gosaukamm, dachsteingruppe, oberösterreich (autriche): norien (dachsteinkalk) 1985 diplopora adnetensis .p. di stefano & senowbari-daryan, pl. iv, fig. 1-2 & 5; pl. vi, fig. 5 pars; pl. vii, fig. 5 pars.mte pellegrino, s mondello, n palermo, sicile (italie): norien 1989 diplopora adnetensis .stanton & e. flügel, pl. 39, fig. 2; pl. 43, fig. 8 & 10.plattenkogel, steinplatte, w lofer, salzburg (autriche): rhétien supérieur 1989 diplopora .stanton & e. flügel, pl. 43, fig. 9.plattenkogel, steinplatte, w lofer, salzburg (autriche): rhétien supérieur 1992 diplopora .berger & kaever, fig. 2.22.c-d.hallein, salzburg (autriche): rhétien 1993 diplopora adnetensis .senowbari-daryan & e. flügel, pl. 10, fig. 4.gruber, feichtenstein, hintersee, salzburg (autriche): rhétien supérieur 1999 diplopora adnetensis .bernecker et al., pl. 39, fig. 6-7.adnet, hallein, salzburg (autriche): rhétien supérieur diplopora alta endo 1961 1961b diplopora alta n. sp.endo, pl. 16, fig. 5.w nagaoka, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 17, fig. 4.n manganji, santō-machi, sakata-gun, shigaken, honshū (japon): permien inférieur (samegai fm).holotype: pl. 16, fig. 5, lame mince n° 510605-2, geological survey of japan (japon) 32 geologia croatica 53/1 diplopora americana johnson 1951 1951 diplopora americana n. sp.johnson, pl. 8, fig. 5.apache mts, texas (états-unis d’amérique): guadalupien (probablement ? capitanien).type: pl. 8, fig. 5, lame mince n° 1084, collection h.j. johnson, colorado school of mines, golden, colorado (états-unis d’amérique) 1963 diplopora americana .johnson, pl. 53, fig. 2, extrait de johnson (1951: pl. 8, fig. 5) 1965 diplopora americana .kordé, pl. liv, fig. 5-6.chanakhchi (arménie): guadalupien 1993 diplopora americana .vachard et al., pl. i, fig. 6.s ermióni, argolís (grèce): djulfien (galet dans une “coulée boueuse” kimméridgienne de la fm de potami) diplopora anatoliana güvenç 1970 1965 diplopora sp.güvenç, pl. m15, fig. 1.f; pl. a8, fig. 8.w taurus (turquie): permien “supérieur” 1970 diplopora anatoliana n. sp.güvenç, pl. x, fig. 5.kemer, wsw antalya, se mugla (turquie): permien “supérieur” (pi i); pl. x, fig. 6-8.cevizli-aladag / bademli, n alanya (turquie): permien “supérieur” (pii).holotype: pl. x, fig. 6, lame mince n° t.g.-k-i-1811; paratype: pl. x, fig. 5, lame mince n° t.g.-k-i-1817, collection t. güvenç, muséum d’histoire naturelle du m.t.a., ankara (turquie) 1979 (nom. nud.) albertaporella anatoliana n. comb.güvenç, p. 633, non figurée *diplopora annulata (schafhäutl 1853) 1863 [= forma trichophora pia 1920; = gyroporella annulata (schafhäutl 1853) gümbel 1872; d’abord considérée comme un bryozoaire: nullipora annulata schafhäutl 1853, puis comme un bivalve perforant: gastrochaena annulata (schafhäutl 1853) stoppani 1857 ] 1853 nullipora annulata n. sp.schafhäutl, pl. vi, fig. 1.a-f.zugspitze, bayern (allemagne).types: pl. vi, fig. 1.a-f 1857 gastrochaena annulata n. comb.stoppani, p. 373-376, non figurée 1857 gastrochaena obtusa n. sp.stoppani, p. 376, non figurée.type non figurée 1858 gastrochaena obtusa .stoppani, pl. 16, fig. 1-10.nombreuses localités, lombardia trentino alto adige (italie): trias supérieur 1863 diplopora annulata n. gen. n. comb.schafhäutl, pl. lxv.e, fig. 6.a-b.zugspitze, bayern (allemagne) 1863 diplopora articulata n. sp.schafhäutl, pl. lxv.e, fig. 16.a-b, 17.a-b & 18.a-b.zugspitze, bayern (allemagne).types: pl. lxv.e, fig. 16.a-b, 17.a-b & 18.a-b 1863 diplopora porosa n. sp.schafhäutl, pl. lxv.e, fig. 5.a-b, 9.a-b, 10.a-b, 11.a-b, 12.a-b, 13.a-b, 14.a-b & 15.a-b.zugspitze, bayern (allemagne).types: pl. lxv.e, fig. 5.a-b, 9.a-b, 10.a-b, 11.a-b, 12.a-b, 13.a-b, 14.a-b & 15.a-b 1865 gastrochaena obtusa .stoppani, pl. 59, fig. 22.songavazzo, s rovetta n alto-cerete, e clusone, lombardia (italie): trias supérieur (couches à a. contorta) 1867 diplopora . schafhäutl, pl. i, fig. 1.b-d, f-g & q.zugspitze, bayern (allemagne) 1867 diplopora annulata .schafhäutl, pl. i, fig. 1.k & m-n.zugspitze, bayern (allemagne) 1867 diplopora porosa .schafhäutl, pl. i, fig. 1.a, 1.e, 1.h-i, 1.l & 1.o-p.zugspitze, bayern (allemagne) 1872 gyroporella annulata n. comb.gümbel, pl. d.ii, fig. 1.a-c.haute silésie (pologne): trias moyen; pl. d.ii, fig. 1.d-g & 1.x-z.nombreuses localités (allemagne, autriche, hongrie, italie, suisse, ...) 1872 gyroporella multiserialis n. sp.gümbel, pl. d.iii, fig. 11.a-d.mendola, trentino alto adige (italie): trias moyen (mendoladolomit).types: pl. d.iii, fig. 11.a-d, collection c.w. gümbel (coll. prof. pichler), münchen (allemagne) 1872 (?) gyroporella cylindrica n. sp.gümbel, pl. d.ii, fig. 2.e-f.haute silésie (pologne): trias moyen; pl. d.ii, fig. 2.a-d, 2.g-i, 2.k-o & 2.aa.haute silésie (pologne): trias moyen, et/ou pertisau, achensee, tirol (autriche).types: pl. d.ii, fig. 2.a-i, 2.k-o & 2.aa, collection c.w. gümbel (coll. prof. pich ler), münchen (allemagne) 1872 (?) gyroporella macrostoma n. sp.gümbel, pl. d.ii, fig. 4.a-b.mendola, trentino alto adige (italie): trias moyen (mendoladolomit).types: pl. d.ii, fig. 4.a-b, collection c.w. gümbel (coll. prof. pichler), münchen (allemagne) 1872 (? pars) gyroporella silesiaca n. sp. [? = diplopora nodosa ].gümbel, pl. d.iii, fig. 6.jemielnica / himmelwitz, ne strzelce opolskie, haute silésie (pologne): trias moyen; pl. d.iii, fig. 7.a-b.mendola, trenti33granier & grgasoviê: les algues dasycladales du permien et du trias... no alto adige (italie): trias moyen (mendoladolomit).type: pl. d.iii, fig. 6, collection c.w. güm bel, münchen (allemagne) 1876 diplopora , gruppe der annulatae.benecke, pl. xxii(2), fig. 5 & 7-11; pl. xxiii(3), fig. 3, 5 & 8.sasso mattilono, esino lario, e lago di como, lombardia (italie): trias moyen (esinokalk / fm del calcare di esino); pl. xxii(2), fig. 12.val vachera, esino lario, e lago di como, lombardia (italie): trias moyen (esinokalk / fm del calcare di esino) 1877 non gyroporella multiserialis [= teutloporella herculea ].karrer, pl. xvi.b, fig. 15 1878 gyroporella annulata .alth, pl. vi, fig. 9, extrait de gümbel (1872: pl. d.ii, fig. 1.a); pl. vi, fig. 10, extrait de gümbel (1872: pl. d.ii, fig. 1.c) 1878 gyroporella cylindrica .alth, pl. vi, fig. 11.a-b, extrait de gümbel (1872: pl. d.ii, fig. 2.e-f) 1887 diplopora sp.solms-laubach, fig. 4.a, extrait de benecke (1876: pl. xxiii(3), fig. 3 pars); fig. 4.b, extrait de benecke (1876: pl. xxii(2), fig. 9 pars) 1890 (?) gyroporella cylindrica .schimper & schenk, fig. 30, n° 6 (à gauche), extrait de gümbel (1872: pl. d.ii, fig. 2.a); fig. 30, n° 6 (à droite), extrait de gümbel (1872: pl. d.ii, fig. 2.aa); fig. 30, n° 6.a, extrait de gümbel (1872: pl. d.ii, fig. 2.m) 1890 gyroporella annulata .schimper & schenk, fig. 30, n° 7 (à droite), extrait de gümbel (1872: pl. d.ii, fig. 1.a); fig. 30, n° 7 (à gauche), extrait de gümbel (1872: pl. d.ii, fig. 1.b) 1890 diplopora sp.schimper & schenk, fig. 31, n° 1, extrait de benecke (1876: pl. xxiii(3), fig. 3 pars); fig. 31, n° 2, extrait de benecke (1876: pl. xxii(2), fig. 9 pars) 1895 diplopora porosa .salomon, pl. i, fig. 1, 2.a-c, 3.a-b & 4-5.marmolada, trentino alto adige véneto (italie): trias moyen (esinokalk / fm del calcare di esino) 1896 diplopora gurmarae n. sp.de lorenzo, pl. xv, fig. 3.se mte gurmara, valle del chiotto, lagonegro, basilicata (italie): trias moyen.type: pl. xv, fig. 3 1898 diplopora .seward, fig. 35.b, extrait de benecke (1876: pl. xxiii(3), fig. 3 pars) 1899 diplopora annulata .tornquist, pl. xviii, fig. 5.a-b.pollichero, fongara, mte spitz, s recoaro terme, w schio, véneto (italie): trias moyen (monte spitz limestone); pl. xviii, fig. 7.san rocco, tretto, n schio, véneto (italie): trias moyen (monte spitz limestone) 1899 diplopora multiserialis n. comb.tornquist, pl. xviii, fig. 8.san rocco, tretto, n schio, véneto (italie): trias moyen (monte spitz limestone) 1903 g y r o p o r e l l a (d i p l o p o r a ) porosa [sic].tommasi, pl. xviii(iii), fig. 30, extrait de stoppani (1865: pl. 59, fig. 22) 1906 diplopora rauffi n. sp.ahlburg, pl. iii, fig. 1.granice / granietz, imielin, haute silésie (pologne): trias moyen (oberen dolomite).type: pl. iii, fig. 1 1907 diplopora porosa .steinmann, fig. 10.a.marmolada, trentino alto adige (italie): ladinien 1908 diplopora annulata .arthaber, pl. 37, fig. 8, extrait de gümbel (1872: pl. d.ii, fig. 1.b) 1908 diplopora multiserialis .arthaber, pl. 37, fig. 9, extrait de gümbel (1872: pl. d.iii, fig. 11.b) 1911 g y r o p o r e l l a (d i p l o p o r a ) porosa [sic].tommasi, pl. i, fig. 1.a-b.ghegna, valsecca, roncobello, n bergamo, lombardia (italie): trias 1912 diplopora annulata .pia, pl. vii(vi), fig. 1-2 & 14-15.origine inconnue; pl. vii(vi), fig. 3-8.höllengebirge, oberösterreich (autriche): trias ? moyen (wettersteinkalk); pl. vii(vi), fig. 9-11.s windhag, ne grünau im almtal, oberösterreich (autriche): trias ? moyen (wettersteinkalk); pl. vii(vi), fig. 12-13.sw malurch, n pontebba / pontafel, friuli venezia giulia (italie): trias moyen (spizze-kalk); pl. vii(vi), fig. 16.steyrtal, sengsengebirge, oberösterreich (autriche): trias ? moyen (wettersteinkalk); pl. vii(vi), fig. 17.ehrwald, gaistal, tirol (autriche): alpenkalk supérieur (chemnizienkalk); pl. viii(vii), fig. 1-2.windhag, ne grünau im almtal, oberösterreich (autriche): trias ? moyen (wettersteinkalk) 1915 (?) gyroporella cylindrica .négris, pl. xii, fig. a.gourizi (grèce): trias; pl. xii, fig. ß.tatoï, parnassós mts (grèce): trias 1919 (?) diplopora annulata .négris, pl. xxviii, fig. 1.arachnaeon, argolís (grèce): trias; pl. xxix, fig. 3.gourizi, kiourka kakossalessi (grèce): trias; pl. xxix, fig. 4.tatoï, parnassós mts (grèce): trias 1920 diplopora annulata var. debilis (forma trichophora) n. stat. n. comb.pia, pl. v, fig. 24.weißen wand, stílves / stilfes, se vipiteno / sterzing, trentino alto adige (italie): ladinien 1920 diplopora annulata ? var. dolomitica (forma trichophora) n. stat. n. comb.pia, pl. v, fig. 22.mudrog34 geologia croatica 53/1 no, pizzo cainallo, esino lario, e lago di como, lombardia (italie): ladinien (esinokalk / fm del calcare di esino) 1920 diplopora annulata var. d o l o m i t i c a (forma trichophora) n. stat. n. comb.pia, pl. v, fig. 12.crnopac, graëac, velebit mt (croatie): ladinien; pl. v, fig. 13.mali halan sv. rok, velebit mt (croatie): ladinien 1920 (nom. nud.) diplopora annulata var. septemtrionalis (forma trichophora) n. var.pia, pl. v, fig. 14-15 & 23.pertisau, achensee, tirol (autriche): ladinien (wettersteinkalk); pl. v, fig. 25.steinbach am attersee, höllengebirge, oberösterreich (autriche): ladinien (wettersteinkalk); pl. v, fig. 16 & 20.haute silésie (pologne): ladinien.types: pl. vii(vi), fig. 1-2 in pia (1912), lame mince n° xiii/1; pl. vii(vi), fig. 3 & 6 in pia (1912), lame mince n° ii/5; pl. vii(vi), fig. 4-5 in pia (1912), lame mince n° ii/2; pl. vii(vi), fig. 7-8 in pia (1912), lame mince n° xxv/3; pl. vii(vi), fig. 9 in pia (1912), lame mince n° xxv/1; pl. vii(vi), fig. 10 in pia (1912), lame mince n° xl/2; pl. vii(vi), fig. 11 in pia (1912), lame mince n° xl/1; pl. vii(vi), fig. 12 in pia (1912), lame mince n° xii/1; pl. vii(vi), fig. 13 in pia (1912), lame mince n° lxix/1; pl. vii(vi), fig. 14 in pia (1912), lame mince n° l/2; pl. vii(vi), fig. 15 in pia (1912), lame mince n° lxxvi/1; pl. vii(vi), fig. 16 in pia (1912), lame mince n° l/?; pl. vii(vi), fig. 17 in pia (1912), lame mince n° lxxvi/?; pl. viii (vii), fig. 1 in pia (1912), lame mince n° lxi/2; pl. viii (vii), fig. 2 in pia (1912), lame mince n° xxiv/1; pl. v, fig. 14-16, 20, 23 & 25, lames minces n° ?, collection j. von pia, naturhistorisches museum, wien (autriche) 1920 non (nom. nud.) diplopora annulata var. septemtrionalis (forma vesiculifera) n. var. [= kantia dolomitica].pia, pl. v, fig. 17.1 des types: pl. v, fig. 17, lame mince n° ?, collection j. von pia, naturhistorisches museum, wien (autriche) 1921 diplopora annulata .bubnoff, pl. x, fig. 13.forno, n predrazzo, val di fiemme, trentino alto adige (italie): ladinien 1921 kantia crassipora n. sp.bubnoff, pl. x, fig. 8-10.forno, n predrazzo, val di fiemme, trentino alto adige (italie): ladinien.types: pl. x, fig. 8-10 1921 kantia dolomitica var. s u b a n n u l a t a n. var.bubnoff, pl. x, fig. 4-7.forno, n predrazzo, val di fiemme, trentino alto adige (italie): ladinien.types: pl. x, fig. 4-7 1925 (?) diplopora annulata .diener (pia), pl. xxvi, fig. 3.esino lario, e lago di como, lombardia (italie): ladinien (esinokalk / fm del calcare di esino) 1925 diplopora annulata var. d o l o m i t i c a.pia, pl. i, fig. 5-6.mali halan sv. rok, velebit mt (croatie): anisien; pl. i, fig. 7.extrait de pia (1920: pl. v, fig. 13) 1925 non diplopora annulata var. dolomitica [= kantia dolomitica].pia, pl. i, fig. 4 1926 (? pars) diplopora silesiaca n. comb. [? = diplopora nodosa ].assmann, p. 505, non figurée 1927 diplopora annulata .ogilvie gordon, pl. ix, fig. 6.val di fassa, trentino alto adige (italie): marmolatakalk; pl. x, fig. 13.sasso lungo / langkofel, santa cristina / st. christina, val gardena / grödnertal, trentino alto adige (italie): trias moyen (schlerndolomit) 1928 diplopora annulata .cosijn, fig. 1.a-e.olmo al brembo, valle brembana, n bergamo, lombardia (italie): trias moyen (esinokalk / fm del calcare di esino) 1928 (?) diplopora silesiaca .schmidt, fig. 12, extrait de gümbel (1874: pl. d.iii, fig. 6) 1 9 2 8 (nom. nud.) diplopora annulata var. s e p t e n t r i o n a l i s [s i c].schmidt, fig. 8.a, extrait de ahlburg (1906: pl. iii, fig. 1); fig. 8.b, extrait de pia (1920: pl. v, fig. 16) 1932 diplopora annulata .pia, fig. p. 13st. aegyd, niederösterreich (autriche): trias moyen 1937 diplopora annulata .andrusov, pl. i, fig. 1.æarnovická dolina, vel’ká fatra (slovaquie): ladinien (choë-dolomit) 1940c diplopora annulata .pia, pl. 3, fig. 5; pl. 4, fig. 6-9.höllengebirge, oberösterreich (autriche): ladinien (wettersteinkalk) 1943 diplopora annulata .pia, pl. v, fig. 14.jansenmäuer, grünau im almtal, oberösterreich (autriche): ladinien (wettersteinkalk) 1944 diplopora annulata .johnson, pl. 302, fig. 6, extrait de pia (1920: pl. v, fig. 16); pl. 302, fig. 7, extrait de pia (1920: pl. v, fig. 22); pl. 302, fig. 8, extrait de pia (1920: pl. v, fig. 14); pl. 302, fig. 10, extrait de pia (1920: pl. v, fig. 15) 1944 non diplopora annulata [= kantia dolomitica].johnson, pl. 302, fig. 3, extrait de pia (1920: pl. v, fig. 21); pl. 302, fig. 4, extrait de pia (1920: pl. v, fig. 27); pl. 302, fig. 5, extrait de pia (1920: pl. v, fig. 26) 35granier & grgasoviê: les algues dasycladales du permien et du trias... 1944 non diplopora annulata [= kantia praecursor ].johnson, pl. 302, fig. 9, extrait de pia (1920: pl. v, fig. 28) 1945 diplopora annulata .wirz, fig. 2-3.mte san giorgio, ticino (suisse): ladinien 1949 diplopora annulata .de sitter & de sitter-koomans, pl. xxi, fig. 2.zucco orscellera, se introbio, valsassina, e lago di como, lombardia (italie): ladinien (esinokalk / fm del calcare di esino) 1950 diplopora annulata .herak, pl. i, fig. 2-3.zrmanja-vrelo, nw knin (croatie): ladinien; pl. ii, fig. 1-2; pl. iv, fig. 1 pars.grgin brijeg, velebit mt (croatie): ladinien 1950 diplopora annulatissima .herak, pl. ii, fig. 3.grgin brijeg, velebit mt (croatie): ladinien 1950 teutloporella vicentina.herak, pl. i, fig. 1.grgin brijeg, velebit mt (croatie): ladinien 1954 diplopora annulata .rosenberg & zapfe in götzinger et al., pl. 1, fig. 11.göller decke, st. aegyd, niederösterreich (autriche): ladinien (wettersteinkalk) 1955 diplopora annulata .hagn, pl. v, fig. 1.riedkopf, arnspitzmassiv, mittenwald, e garmischpartenkirchen, bayern (allemagne): ladinien (wettersteinkalk) 1957 diplopora annulata .bystrický, pl. vii, fig. 5.muráňska planina (slovaquie): ladinien; pl. vii, fig. 67.macova dolina, muráňska planina (slovaquie): ladinien 1957 diplopora annulata subsp. annulata n. subsp.herak, p. 52, non figurée 1959 diplopora annulata .andrusov, pl. xi, fig. 1.æarnovická dolina, vel’ká fatra (slovaquie): trias moyen (choë-dolomit) 1959 diplopora pars.“anonyme”, pl. x, bas.mte ozol, n revò, val di non, trentino alto adige (italie): ladinien 1959 non diplopora annulata [= griphoporella curvata ].“anonyme”, pl. xxiv, bas; pl. xxv; pl. xxvi, haut 1960 non cf. gyroporella multiserialis .pastwa-leszczyńska & śl i w iński, pl. ii, fig. 11.ka̧ty (rosowa góra), nw chrzanów, haute silésie (pologne): anisien 1961 diplopora annulata .johnson, pl. 52, fig. 4, extrait de pia (1920: pl. v, fig. 16) 1962a (?) diplopora sp.michard, pl. iv, fig. 6.valle di cavoira, val grana, piemonte (italie): ladinien 1963 diplopora annulata annulata .e. flügel & kirchmayer, pl. x, fig. 3.gutenstein, niederösterreich (autriche): anisien (gutensteiner kalk) 1 9 6 3 (nom. nud.) diplopora annulata septemtrionalis .e. flügel & kirchmayer, pl. x, fig. 2.gutenstein, niederösterreich (autriche): anisien (gutensteiner kalk) 1963 diplopora annulata .herak, fig. 37, extrait de herak (1950: pl. i, fig. 2) 1963 diplopora annulata .kotański, pl. iii, fig. 1-2; pl. iv, fig. 1-2.dl⁄ ugi z ° leb, dolina jaworzynka, se zakopane, tatry (pologne): ladinien inférieur 1963 (?) diplopores.kotański, pl. v, fig. 1; pl. vi, fig. 1.l⁄ ysanki, dolina za bramka̧ , zakopane, tatry (pologne): ladinien inférieur; pl. vi, fig. 2.dolina maly z ° leb, s zakopane, tatry (pologne): ladinien inférieur 1963 diplopora annulata .ott, fig. 1, 7-9, 11-13, 14 pars, 16 & 19.karwendelgebirge, tirol (autriche): ladinien (wettersteinkalk) 1964 diplopora annulata var. a n n u l a t a nom. nov.bystrický, pl. xxix, fig. 1-3.domica keëovo, se pleπivec, slovenský kras (slovaquie): ladinien (wettersteinkalk) 1964 ? diplopora annulata .bystrický, pl. xxix, fig. 4.domica keëovo, se pleπivec, slovenský kras (slovaquie): ladinien (wettersteinkalk) 1964 diplopora annulata .dercourt, pl. ix, fig. 1-2.skafa óros, sofikón, korinthía (grèce): ladinien 1965 diplopora annulata .andrusov, fig. 8.æarnovická dolina, vel’ká fatra (slovaquie): trias moyen (choë-dolomit); fig. 15, extrait de andrusov (1959: pl. xi, fig. 1) 1965 diplopora annulata subsp. a n n u l a t a .herak, pl. vi, fig. 2.debela greda, orlovica, n knin (croatie): ladinien; pl. vi, fig. 3.vrace, sw graëac, velebit mt (croatie): ladinien; pl. vi, fig. 4.crni vrh, velika popina, velebit mt (croatie): ladinien 1965 diplopora annulata .herak, pl. vii, fig. 3.gradina, vrkljanski ponori, sv. rok, lika (croatie): ladinien; pl. vii, fig. 4.debela greda, orlovica, n knin (croatie): ladinien; pl. xii, fig. 7 pars.velika vrπina, sv. rok, lika (croatie): ladinien 1965a diplopora annulata var. a n n u l a t a , forma trichophora.zanin buri, pl. 54, fig. 4.sas carlên, esino lario, e lago di como, lombardia (italie): ladinien supérieur (esinokalk / fm del calcare di esino); pl. 54, fig. 5-6.cugno di sotto, valle brembana, n bergamo, lombardia (italie): ladinien moyen36 geologia croatica 53/1 supérieur (esinokalk / fm del calcare di esino); pl. 55.ghegna, valsecca, roncobello, n bergamo, lombardia (italie): ladinien supérieur (esinokalk / fm del calcare di esino) 1965a diplopora annulata var. annulata .zanin buri, pl. 54, fig. 1-3.ghegna, valsecca, roncobello, n bergamo, lombardia (italie): ladinien (esinokalk / fm del calcare di esino) 1965a diplopora annulata var. d e b i l i s, forma trichophora.zanin buri, pl. 57, fig. 1.c.cugno di sotto, valle brembana, n bergamo, lombardia (italie): ladinien moyen-supérieur (esinokalk / fm del calcare di esino) 1966 diplopora annulata var. a n n u l a t a .bystrický, pl. viii, fig. 7.ponická lehôtka poniky oravce postredná môlëa, e banská bystrica (slovaquie): ladinien inférieur (wettersteinkalk) 1966 diplopora annulata var. a n n u l a t a .peræel (bystrický), pl. xix, fig. 1-2.n ostrý vrch, biele pohorie, malé karpaty (slovaquie): ladinien 1967a non diplopora cf. annulata [= teutloporella herculea ].herak, pl. 9, fig. 3-4 1967 (?) diplopora annulata .michard, pl. viii, fig. 1, extrait de michard (1962a: pl. iv, fig. 6); pl. viii, fig. 23.valle di cavoira, val grana, piemonte (italie): ladinien 1967 diplopora annulata .pantiê, pl. iv, fig. 5.sokolarica, tara mt, w serbie (yougoslavie): ladinien 1968 diplopora annulata .schindlmayr, pl. v, fig. 1 & 3; pl. vi, fig. 5.weißen wand, stílves / stilfes, se vipiteno / sterzing, trentino alto adige (italie): ladinien 1969 non diplopora annulata [= kantia dolomitica].bloch & lefevre, pl. i, fig. 1-3 & 10-12 1969 diplopora annulata var. annulata .diaconu & dragastan, pl. vi, fig. 3; pl. vii, fig. 1-2.dealul glimeia, apuseni mts (roumanie): ladinien; pl. vii, fig. 3.dealul glimeia, apuseni mts (roumanie): anisien supérieur fig. 8 diplopora annulata subsp. annulata (herak, 1965, pl. vi, fig. 3), x18. fig. 9 diplopora annulata (herak, 1965, pl. vii, fig. 3), x18. 37granier & grgasoviê: les algues dasycladales du permien et du trias... 1970 diplopora annulata .büchner, fig. 15-16.bruckstein, weng bei admont-gstatterboden, gesäuse, steiermark (autriche): ladinien (wettersteinkalk) 1970 diplopora annulata a n n u l a t a .patrulius, pl. iii, fig. 1.glimeiul mic, pǎdurea craiului, apuseni mts, bihor (roumanie): ladinien 1971 diplopora annulata .zorn, pl. 4, fig. 4 pars.mte san salvatore, s lugano, ticino (suisse): ladinien (oberer salvatoredolomit); pl. 17, fig. 1.mte san giorgio, ticino (suisse): anisien (unterer salvatoredolomit) 1972 diplopora annulata .kodra, pl. 2, fig. 2 & 5 pars.prozhmë, kollatë, valbona (albanie): ladinien (suita e selimajt) 1972 diplopora annulata .miπík, pl. xxxviii, fig. 2; pl. lxi, fig. 3.harmanec, vel’ká fatra (slovaquie): ladinien (choë-dolomit) 1972 diplopora annulata .pantiê & rampnoux, pl. ii, fig. 3.ljubiπnja mt, monténégro (yougoslavie): ladinien 1972a diplopora annulata .zorn, pl. iii, fig. 2.mte san salvatore, s lugano, ticino (suisse): anisien supérieur ladinien (mittlerer salvatoredolomit) 1972b diplopora annulata .zorn, fig. 2.1-4 & 3.1.ghegna, valsecca, roncobello, n bergamo, lombardia (italie): ladinien; fig. 2.5.mte san salvatore, s lugano, ticino (suisse): ladinien 1973 diplopora annulata forma trichophora.popa & dragastan, pl. xviii, fig. 69-71 & 72 pars; pl. xx, fig. 78.dealul ruget remeţi, w valea boiului, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien-ladinien, illyrien supérieur langobardien 1974 diplopora annulata .zorn, pl. i, fig. 1.mte san salvatore, s lugano, ticino (suisse): anisien-ladinien (salvatoredolomit); pl. i, fig. 2-4 & 6; pl. ii, fig. 2.mte san salvatore, s lugano, ticino (suisse): ladinien inférieur (mittlerer salvatoredolomit); pl. i, fig. 5; pl. ii, fig. 8.cima dei cic, pizzo cainallo, esino lario, e lago di como, lombardia (italie): ladinien supérieur (esinokalk / fm del calcare di esino); pl. i, fig. 7; pl. ii, fig. 1 & 7.varenna-esino lario, e lago di como, lombardia (italie): ladinien supérieur (esinokalk / fm del calcare di esino) 1975 diplopora annulata .pantiê-prodanoviê, pl. xlvi, fig. 1 pars; pl. xlvii, fig. 1 pars.sokolarica, tara mt, w serbie (yougoslavie): ladinien 1976 diplopora annulata .epting et al., fig. 8.d pars.mte spitz, s recoaro terme, w schio, véneto (italie): anisien-ladinien, illyrien supérieur fassanien (monte spitz limestone) 1976 diplopora annulata forma trichofora [sic].hanáëek, pl. vii, fig. 2 pars; pl. viii, fig. 1, 2 pars & 3 pars.stráæovské vrchy, e trencín (slovaquie): ladinien (wettersteinkalk) 1977 diplopora annulata .freels & hemleben, fig. 5.mont-ral, nw tarragona (espagne): trias moyen 1977 diplopora annulata .zorn, fig. 1.b-c.alpes (?): trias moyen 1978 diplopora annulata .anelkoviê, pl. lxix, fig. 2, extrait de herak (1965: pl. xii, fig. 7) 1978 diplopora annulata .bousquet et al., pl. i, fig. 2-3.e mte cava del oro, w san donato di ninea, calabria (italie): ladinien 1978 diplopora annulata .e. flügel, pl. 25 pars.amtmanngalgen, johnsbach, gesäuse, steiermark (autriche): ladinien (wettersteinkalk) 1978 teutloporella nodosa .e. flügel, pl. 22, fig. 5.velebit mt (croatie): anisien 1978 diplopora annulata .ramovπ, fig. 7.meæaklja, jesenice (slovénie): carnien, cordevolien 1979 diplopora annulata .güvenç, p. 630, non figurée 1979 (nom. nud.) diplopora septentrionalis n. stat. [sic].güvenç, p. 630, non figurée 1979 diplopora annulata annulata .kotański, pl. 80, fig. 13.tatry (pologne): ladinien inférieur 1980 diplopora annulata .ramovπ, fig. 8, extrait de ramovπ (1978: fig. 7) 1981 diplopora annulata .gaetani et al., fig. 7 & 15.8.látemar, trentino alto adige véneto (italie): ladinien inférieur (látemar limestone) 1982 diplopora annulata var. annulata .bystrický, pl. 2, fig. 1 pars & 3-4; pl. 4, fig. 2 pars & 3 pars.slatinka nad bebravou ©ípkov, stráæovské vrchy, e trencín (slovaquie): anisien-ladinien 1982 diplopora annulata .e. flügel, pl. 33 pars, extrait de e. flügel (1978: pl. 25 pars) 1983 diplopora annulata .fois & jadoul, pl. 1, fig. a pars.mte bruca, n pontebba / pontafel, friuli venezia giulia (italie): anisien, illyrien (a v i a s i a n u s zone, calcari nodulari superiori); pl. 1, fig. f.1.38 geologia croatica 53/1 mte bruca, n pontebba / pontafel, friuli venezia giulia (italie): anisien, illyrien (a v i a s i a n u s z o n e , calcari nodulari inferiori) 1984 diplopora annulata .ogorelec et al., pl. 6, fig. 1 pars & 2.planica, w kranjska gora (slovénie): carnien, cordevolien 1986 diplopora annulata var. a n n u l a t a .bystrický, pl. iv, fig. 1.©ípkov, stráæovské vrchy, e trencín (slovaquie): ladinien (diplopora annulata taxon-range zone); pl. iv, fig. 6.slatinka nad bebravou, stráæovské vrchy, e trencín (slovaquie): ladinien (diplopora annulata taxon-range zone) 1986 diplopora annulata annulata .kotański, pl. civ, fig. 13, extrait de kotański (1979: pl. 80, fig. 13); pl. cv, fig. 1, extrait de pia (1920: pl. v, fig. 16) 1986 non diplopora annulata annulata [= kantia dolomitica].kotański, pl. cv, fig. 2, extrait de pia (1920: pl. v, fig. 21) 1986 diplopora annulata .kotański, pl. cv, fig. 3-7.forage z ° arki letnisko 11-z, w z ° arki letnisko, ene kozieglowy, haute silésie (pologne): anisien, illyrien 1986 (?) diplopora annulata .sudar, pl. xxvi, fig. 3.mitrovac, tara mt, w serbie (yougoslavie): ladinien (wettersteinkalk) 1987 diplopora annulata .braga & martin, pl. i, fig. 6.sierra de baza, gor baza, granada (espagne): anisien supérieur ladinien 1988 diplopora annulata .pfeiffer, pl. 8, fig. 5; pl. 11, fig. 4-5.gartnerkofel, s hermagor, kärnten (autriche): ladinien, fassanien (schlerndolomit) 1988 (?) diplopora cf. a n n u l a t a .pfeiffer, pl. 11, fig. 6.gartnerkofel, s hermagor, kärnten (autriche): ladinien, fassanien (schlerndolomit) 1988 diplopora annulata .sartorio & venturini, p. 55, extrait de “anonyme” (1959: pl. x, bas) 1989 diplopora annulata v a r . a n n u l a t a .buëek, pl. iii, fig. 4.n zárub, malé karpaty (slovaquie): ladinien (wettersteindolomit) 1989 (?) diplopora annulata var. ind.buëek, pl. iii, fig. 5.buková, malé karpaty (slovaquie): ladinien (wettersteindolomit) 1990 diplopora annulata .ciarapica et al., fig. 8.top.la cercharia, ne brienza sw potenza, basilicata (italie): ladinien (monte facito fm) 1990 diplopora annulata .scheuber, pl. 9, fig. 2 pars.mte rove, recoaro terme, w schio, véneto (italie): anisien-ladinien, illyrien-fassanien moyen (monte spitz limestone); pl. 11, fig. 5.mte spitz, s recoaro terme, w schio, véneto (italie): anisien-ladinien, illyrien-fassanien moyen (monte spitz limestone) 1991 non diplopora annulata [= kantia dolomitica].barattolo, pl. iii, fig. 2 1991 diplopora .tiπljar et al. (sokaë), pl. iii, fig. 1.vrace, sw graëac, velebit mt (croatie): ladinien 1993 diplopora annulata .senowbari-daryan et al., pl. 55, fig. 2.piz da perez, valdáora / olang, pusteria / pustertal, trentino alto adige (italie): anisien (fm del serla superiore), illyrien inférieur; pl. 55, fig. 3 & 5.piz da perez, valdáora / olang, pusteria / pustertal, trentino alto adige (italie): anisien (fm del serla superiore); pl. 55, fig. 4.flatschkofel, e s. vigilio di marebbe / st. vigil, s valdáora / olang, trentino alto adige (italie): anisien, pelsonien supérieur 1993 (?) ? diplopora annulata .senowbari-daryan et al., pl. 55, fig. 7.piz da perez, valdáora / olang, pusteria / pustertal, trentino alto adige (italie): anisien (fm del serla superiore) 1994 (?) diplopora annulata .rinaldo & jadoul, fig. 17.val brenta alta, sw cima brenta, gruppo di brenta, trentino alto adige (italie): carnien inférieur (dolomia di val d’adige) 1997 diplopora annulata .pugliese, pl. 1, fig. 6-9.mte toff, n tione di trento, gruppo di brenta, trentino alto adige (italie): ladinien diplopora annulata var. [“subsp.” ] annulata herak 1957 [variété superflue du fait des transferts des variétés dolomitica pia 1920 et debilis (gümbel 1872) pia 1920 dans le genre kantia pia 1912, emend. güvenç 1979; = forma trichophora pia 1920 ] diplopora annulata var . brianconnensis schneegans 1933 [synonyme postérieur de diplopora uniserialis (pia 1920) güvenç 1979 et/ou de kantia uniserialis (pia 1920) güvenç 1979 ] 39granier & grgasoviê: les algues dasycladales du permien et du trias... diplopora annulata var. debilis (forma trichophora) (gümbel 1872) pia 1920 [cf. diplopora annulata (schafhäutl 1853) 1863 ] diplopora annulata var. debilis (forma vesiculifera) (gümbel 1872) pia 1920 [cf. kantia debilis (gümbel 1872) baretti 1919, emend. güvenç 1979 ] diplopora annulata var. [“subsp.” ] dolomitica (pia 1912) herak 1957 [cf. kantia dolomitica pia 1912, emend. güvenç 1979; = forma vesiculifera pia 1920 ] diplopora annulata var. dolomitica (forma trichophora) (pia 1912) 1920 [cf. diplopora annulata (schafhäutl 1853) 1863 ] diplopora annulata var. dolomitica (forma vesiculifera) (pia 1912) 1920 [cf. kantia dolomitica pia 1912, emend. güvenç 1979 ] diplopora annulata var . physoporelloidea pastwa-leszczyn´ ska et ś liwiń ski 1960 [synonyme postérieur de physoporella praealpina pia 1920, d’après kotański, 1979 ] diplopora annulata var. septemtrionalis (forma trichophora) pia 1920, nom. nud. [cf. diplopora annulata (schafhäutl 1853) 1863 ] diplopora annulata var. septemtrionalis (forma vesiculifera) pia 1920, nom. nud. [cf. kantia dolomitica pia 1912, emend. güvenç 1979 ] diplopora annulatissima pia 1920 [synonyme postérieur de kantia monregalensis baretti 1919, d’après herak, 1957 ] diplopora articulata schafhäutl 1863 [synonyme postérieur de diplopora annulata (schafhäutl 1853) 1863, d’après pia, 1912 ] diplopora belcherensis roux ex mamet et roux in mamet et al. 1987 1 9 7 9 a (nom. nud.) diplopora belcherensis n. sp.roux, pl. 21, fig. 1-3.blind fiord, ellesmere, nunavut (canada): assélien inférieur (fm belcher channel).type: pl. 21, fig. 1, lame mince n° cgc 61156, com mission géologique du canada, calgary (canada) 1987 diplopora belcherensis n. sp.mamet & roux in mamet et al., pl. 21, fig. 1-3, extrait de roux (1979a: pl. 21, fig. 1-3).type: pl. 21, fig. 1, lame mince n° cgc 61156, commission géologique du canada, calgary (canada) diplopora beneckei salomon 1895 [cf. macroporella beneckei (salomon 1895) pia 1920 ] diplopora bisulcata endo 1968, nom. nud. 1968b (nom. nud.) diplopora bisulcata n. sp.endo, “chart”, non figurée.type non figuré diplopora borzai bystrický 1978 1978 diplopora borzai n. sp.bystrický, pl. 1, fig. 1-4; pl. 2, fig. 1-4.ese hradová, w tisovec, muráňs k a planina (slovaquie): carnien, ? tuvalien (tisoveckalk).holotype: pl. 1, fig. 1, lame mince n° 5507, collection j. bystricky´, geological institute, slovak academy of sciences, bratislava (slovaquie) 1981a diplopora panormitana n. sp.p. di stefano, pl. i, fig. 1-3; pl. ii, fig. 1-3; pl. iii, fig. 1-4; pl. iv, fig. 14.cozzo di lupo, torretta, s carini, w palermo, sicile (italie): norien.holotype: pl. i, fig. 1, lame mince n° a 20/5; paratypes: pl. i, fig. 2, lame mince n° a 20/4; pl. i, fig. 3, lame mince n° a 20/5; pl. iii, fig. 2, lame mince n° a 20/6; pl. ii, fig. 1 & 3; pl. iii, fig. 1 & 3-4; pl. iv, fig. 1-4, lame 40 geologia croatica 53/1 mince n° a 20/7; pl. ii, fig. 2, lame mince n° a 20/9, collection p. di stefano, museo di geologia dell’università di palermo (italie) 1981b diplopora panormitana .p. di stefano in catalano & d’argenio, fig. 28.c, extrait de p. di stefano (1981a: pl. iii, fig. 3) 1982 diplopora panormitana .senowbari-daryan et al., pl. 23, fig. 3.cozzo di lupo, torretta, s carini, w palermo, sicile (italie): norien 1985 diplopora borzai .p. di stefano & senowbari-daryan, fig. 7 pars & 11; pl. iv, fig. 3, extrait de p. di stefano (1981a: pl. i, fig. 1); pl. iv, fig. 4, extrait de p. di stefano (1981a: pl. iii, fig. 3); pl. iv, fig. 6, extrait de p. di stefano (1981a: pl. ii, fig. 2) diplopora cadorica ogilvie gordon 1935 1935 diplopora cadorica n. sp.ogilvie gordon, pl. v, fig. 2.mte tránego, w pieve di cadore, véneto (italie): trias moyen (mendoladolomit).type: pl. v, fig. 2 diplopora cellulata hurka 1967, nom. nud. 1967 (nom. nud.) diplopora cellulata n. sp.hurka, fig. 14.a-m, 15.a-h & 16.a-k; pl. 6, fig. 6; pl. 7, fig. 1-2 & 4.e bagni di piandimáia / bad maistatt, villabassa / niederdorf, pusteria / pustertal, trentino alto adige (italie): anisien, hydaspien supérieur (prasgser dolomiten).type non désigné: pl. 6, fig. 6; pl. 7, fig. 1-2 & 4, lames minces n° ug1/1-ug1/45, n° ug1/15, schliffsammlung des institutes für spezielle botanik der universität tübingen (allemagne) 1972c (nom. nud.) diplopora cellulata .ott, fig. 3, n° 1-2.martinswand, innsbruck, tirol (autriche): anisien 1 9 7 3 (nom. nud.) diplopora cellulata .popa & dragastan, pl. iii, fig. 9.w lorǎu, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à dadocrinus communis) 1982 (?) (nom. nud.) diplopora cellulata .farabegoli & levanti, pl. 6, fig. 2 pars.mte tuglia-mte pleros, sappada, véneto (italie): anisien, illyrien supérieur diplopora clavaeformis pia 1920 [cf. clavapora clavaeformis (pia 1920) güvenç 1979 ] diplopora comelicana fois 1979 1979 diplopora comelicana n. sp.fois, pl. 1, fig. 1-7; pl. 2, fig. 1-5; pl. 3, fig. 10.a; pl. 4, fig. 1-12.mte popera, rocca di campo bivacco piovan, belluno, véneto (italie): anisien, illyrien (“algal limestones”, a v i a s i a n u s z o n e ).holotype: pl. 1, fig. 1, lame mince n° cr 10, coll. ss. n. 178, paratypes: pl. 1, fig. 2-7; pl. 2, fig. 1-5; pl. 3, fig. 10.a, lames minces n° cr 10, *a/2, *f/1, a/1, f/3, b/1, p/1, a/2, ef 10c, coll. ss. n. 178-185 & 188; pl. 4, fig. 1-12, coll. m. n. 1745-1755, collection e. fois, laboratorio di micropaleontologia, istituto di paleontologia, università di milano (italie) 1982 (?) diplopora a f f . c o m e l i c a n a.bystrický, pl. 2, fig. 2.slatinka nad bebravou ©ípkov, stráæovské vrchy, e trencín (slovaquie): anisien-ladinien 1983 diplopora comelicana .fois & jadoul, pl. 1, fig. a pars.mte bruca, n pontebba / pontafel, friuli venezia giulia (italie): anisien, illyrien (aviasianus zone, calcari nodulari superiori); pl. 1, fig. c pars, d.1, e & f.2.mte bruca, n pontebba / pontafel, friuli venezia giulia (italie): anisien, illyrien (a v i asianus zone, calcari nodulari inferiori) 1986 diplopora comelicana .bystrický, pl. iv, fig. 2 & 4.poniky, e banská bystrica (slovaquie): ladinien, fassanien (diplopora annulata taxon-range zone) diplopora debilis (gümbel 1872) pia 1912 [cf. kantia debilis (gümbel 1872) baretti 1919, emend. güvenç 1979 ] diplopora decastroi p. di stefano et senowbari-daryan 1985 1985 diplopora decastroi n. sp.p. di stefano & senowbari-daryan, fig. 12; pl. v, fig. 1-6; pl. vi, fig 1-4 & 5 pars; pl. vii, fig. 5 pars.mte pellegrino, s mondello n palermo, sicile (italie): norien.holotype: pl. v, fig. 1-2, lame mince n° p.11.3, collection p. di stefano, coll. a 57, museo di geologia dell’università di palermo (italie) 41granier & grgasoviê: les algues dasycladales du permien et du trias... 1997 diplopora decastroi .de castro, pl. 23, fig. 1.mte pellegrino, s mondello n palermo, sicile (italie): norien diplopora elegans assmann 1926, nom. nud. [cf. oligoporella elegans assmann ex pia 1931 ] diplopora exuberans pia ex zorn 1974, nom. nud. [= diplopora philosophi var . exuberans pia 1942, nom. nud. ] diplopora exuberans var . exuberans zorn 1974, nom. nud. 1920 diplopora philosophi n. comb.pia, pl. v, fig. 9-11.gisement inconnu (? autriche): trias ? moyen (galet d’origine inconnue) 1942 (nom. nud.) diplopora philosophi var. exuberans n. var.pia, p. 28, non figurée.type non figurée 1962b (?) diplopora cf. p h i l o s o p h i.michard, pl. viii, fig. 1-2; pl. ix, fig. 1 & 2 pars.case solano, valle di cavoira, val grana, piemonte (italie): anisien terminal ladinien 1 9 6 5 a (nom. nud.) diplopora philosophi var. e x u b e r a n s.zanin-buri, pl. 60; pl. 61, fig. 1-4.cugno di sotto, valle brembana, n bergamo, lombardia (italie): ladinien moyen-supérieur 1 9 6 7 (?) (nom. nud.) diplopora cf. p h i l o s o p h i cf. var. e x u b e r a n s.michard, pl. viii, fig. 8-9.valle di cavoira, val grana, piemonte (italie): ladinien; pl. viii, fig. 4, extrait de michard (1962b: pl. ix, fig. 1); pl. viii, fig. 5, extrait de michard (1962b: pl. viii, fig. 1 pars); pl. viii, fig. 6, extrait de michard (1962b: pl. viii, fig. 2); pl. viii, fig. 7, extrait de michard (1962b: pl. ix, fig. 2 pars) 1 9 6 9 (nom. nud.) diplopora philosophi var. e x u b e r a n s.diaconu & dragastan, pl. viii, fig. 4-5.dealul glimeia, apuseni mts (roumanie): anisien supérieur 1971 diplopora philosophi philosophi .zorn, pl. 4, fig. 3.ardena, nw brusimpiano, s lugano, ticino (suisse): anisien-ladinien (salvatoredolomit); pl. 17, fig. 9.w ciona, ticino (suisse): anisien supérieur ladinien inférieur (mittlerer salvatoredolomit, gervillienhorizont) 1 9 7 2 b (nom. nud.) diplopora philosophi var. e x u b e r a n s.zorn, fig. 2.6.pizzo cainallo, esino lario, e lago di como, lombardia (italie): trias moyen (esinokalk / fm del calcare di esino); fig. 3.3.galet d’origine inconnue (collection j. von pia) 1 9 7 4 (nom. nud.) diplopora exuberans subsp. exuberans n. stat.zorn, fig. 16.a; pl. ii, fig. 5-6.cima dei cic, pizzo cainallo, esino lario, e lago di como, lombardia (italie): ladinien supérieur (esinokalk / fm del calcare di esino) 1 9 7 7 (nom. nud.) diplopora exuberans exuberans .zorn, fig. 1.e.gruppo di grigna, e lago di como, lombardia (italie): ladinien supérieur diplopora exuberans var . truempyi zorn 1974, nom. nud. 1965a diplopora philosophi philosophi .zanin-buri, pl. 58-59.parlasco, valsassina, e lago di como, lombardia (italie): anisien inférieur 1 9 7 4 (nom. nud.) diplopora exuberans subsp. t r ü m p y i n. subsp.zorn, fig. 16.b; pl. ii, fig. 3.ardena brusimpiano, s lugano, ticino (suisse): ladinien inférieur (gervillienhorizont); pl. ii, fig. 4.campione d’italia, s lugano, ticino (suisse): ladinien inférieur (gervillienhorizont).type non désigné 1977 (nom. nud.) diplopora exuberans trümpyi .zorn, fig. 1.d.ticino (suisse): ladinien inférieur diplopora gümbeli salomon 1895 [cf. griphoporella guembeli (salomon 1895) pia 1920 ] diplopora gurmarae de lorenzo 1896 [synonyme postérieur de diplopora annulata (schafhäutl 1853) 1863, d’après pia, 1920 ] diplopora helvetica (pia 1912) 1920 [cf. poncetella helvetica (pia 1912) güvenç 1979 ] diplopora herculea (stoppani 1857) salomon 1895 [cf. teutloporella herculea (stoppani 1857) pia 1912 ] 42 geologia croatica 53/1 diplopora hexaster (pia 1912) 1920 [cf. poncetella hexaster (pia 1912) güvenç 1979 ] diplopora hexaster susbsp. helvetica (pia 1912) herak 1965 [subsp. superflue; cf. poncetella helvetica (pia 1912) güvenç 1979 ] diplopora hexaster susbsp. hexaster (pia 1912) herak 1965 [subsp. superflue; cf. poncetella helvetica (pia 1912) güvenç 1979 ] diplopora interiecta fenninger 1969 1969 diplopora interiecta n. sp.fenninger, pl. 1, fig. 1-9.n gol-tschesmeh, nw muteh, golpaygan (iran): norien supérieur rhétien.holotype: pl. 1, fig. 1, lame mince n° gol-tschesmeh 13/6, collection e. fenninger 1979 (?) diplopora cf. i n t e r i e c t a .e. flügel, pl. 2, fig. 7.gosaukamm, dachsteingruppe, oberösterreich (autriche): norien supérieur (dachsteinkalk) 1982 (?) diplopora cf. d. interiecta .senowbari-daryan et al., pl. 23, fig. 4 pars.mte pellegrino, s mondello n palermo, sicile (italie): norien 1982 (?) diplopora cf. d. interiecta .wurm, pl. 33, fig. 4.gosaukamm, dachsteingruppe, oberösterreich (autriche): norien (dachsteinkalk) diplopora latissima endo 1956 1956 diplopora ? latissima n. sp.endo, pl. 26, fig. 5-6; pl. 27, fig. 2.sakaishi, agano-mura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne). holotype: pl. 26, fig. 6, lame mince n° 392; paratypes: pl. 26, fig. 5, lame mince n° 333; pl. 27, fig. 2, lame mince n° 337, department of earth sciences, saitama university, urawa (japon) 1961a diplopora latissima .endo, pl. 4, fig. 8, extrait de endo (1956: pl. 26, fig. 6) diplopora lotharingica benecke 1898 [cf. physoporella lotharingica (benecke 1898) pia 1931 ] diplopora multiserialis (gümbel 1872) tornquist 1899 [synonyme postérieur de diplopora annulata (schafhäutl 1853) 1863, d’après pia, 1912 ] diplopora muranica bystrický 1967 [synonyme postérieur de diplopora tubispora ott 1967, d’après ott, 1968 ] diplopora nodosa schafhäutl 1863, emend. de castro 1979 [= teutloporella nodosa (schafhäutl 1863) pia 1920 ] 1863 diplopora nodosa n. sp.schafhäutl, pl. lxv.e, fig. 19-20.zugspitze, bayern (allemagne).types: pl. lxv.e, fig. 19-20, coll. schafhäutl 1867 bryozoe.schafhäutl, pl. i, fig. 1.r.zugspitze, bayern (allemagne) 1872 gyroporella infundibuliformis n. sp.gümbel, pl. d.iii, fig. 8.a-c.plusieurs localités: mendola, trentino alto adige (italie): trias moyen (mendoladolomit), et/ou zugspitze, bayern (allemagne): trias ? moyen (wettersteindolomit); pl. d.iii, fig. 9.hötting, innsbruck, tirol (autriche); pl. d.iii, fig. 10.mt csiker (hongrie): trias moyen.types: pl. d.iii, fig. 8.a-c, collection c.w. gümbel (coll. prof. pichler), münchen (allemagne) 1872 (? pars) gyroporella silesiaca n. sp.gümbel, pl. d.iii, fig. 6.jemielnica / himmelwitz, ne strzelce opolskie, haute silésie (pologne): trias moyen; pl. d.iii, fig. 7.a-b.mendola, trentino alto adige (italie): trias moyen (mendoladolomit).type: pl. d.iii, fig. 6, collection c.w. gümbel, münchen (allemagne) 1895 diplopora nodosa .salomon, pl. i, fig. 6.a-b, 7.a-c, 8.a-b, 10.a-c, 11.a-b, 12 & 12.a.marmolada, trentino alto adige véneto (italie): trias ? moyen (wettersteinkalk) 43granier & grgasoviê: les algues dasycladales du permien et du trias... 1895 diplopora nodosa var. elliptica n. var.salomon, pl. i, fig. 9.a-b.n marmolada, trentino alto adige véneto (italie): trias ? moyen (wettersteinkalk).types: pl. i, fig. 9.a-b, collection w. salomon, münchen (allemagne) 1920 teutloporella nodosa n. comb.pia, pl. ii, fig. 11-13.marmolada, trentino alto adige véneto (italie): ladinien 1926 (? pars) diplopora silesiaca n. comb.assmann, p. 505, non figurée 1928 (?) diplopora silesiaca .schmidt, fig. 12, extrait de gümbel (1874: pl. d.iii, fig. 6) 1960 non diplopora cf. silesiaca [= physoporella minutula ].pastwa-leszczyńska & śliwiński, fig. 7; pl. iii, fig. 13 [= fig. 7] 1964 problematicum.bystrický, pl. xxxii, fig. 1.slovenský kras (slovaquie): ladinien 1965 teutloporella nodosa .herak, pl. ii, fig. 1.brdo, w træië (slovénie): ladinien; pl. iii, fig. 1-3.orlovica, n knin (croatie): ladinien; pl. iii, fig. 4.debelo brdo, nw knin (croatie): ladinien; pl. iv, fig. 14.©uplje brdo, velika popina, velebit mt (croatie): ladinien 1967 teutloporella nodosa .pantiê, pl. v, fig. 1-3.©ljivovica, tara mt, w serbie (yougoslavie): ladinien 1967 teutloporella nodosa .scandone (de castro), pl. ii.marsico nuevo, basilicata (italie): trias moyensupérieur 1969 teutloporella triasina .diaconu & dragastan, pl. i, fig. 2.dealul glimeia, apuseni mts (roumanie): ladinien 1969 non teutloporella nodosa .diaconu & dragastan, pl. i, fig. 3.dealul glimeia, apuseni mts (roumanie): ladinien 1969 (?) teutloporella nodosa .diaconu & dragastan, pl. i, fig. 4.dealul glimeia, apuseni mts (roumanie): ladinien 1969 t e u t l o p o r e l l a sp. 1.diaconu & dragastan, pl. ii, fig. 1.dealul glimeia, apuseni mts (roumanie): ladinien 1969 (?) t e u t l o p o r e l l a sp. 2.diaconu & dragastan, pl. iv, fig. 9; pl. v, fig. 3.dealul glimeia, apuseni mts (roumanie): ladinien 1970 (?) teutloporella aff. n o d o s a.patrulius, pl. iii, fig. 2.şu n c u i uş, pǎdurea craiului, apuseni mts, bihor (roumanie): ladinien 1971 t e u t l o p o r e l l a n o d o s a .zorn, pl. 17, fig. 6.fornace, n campione d’italia, s lugano, ticino (suisse): anisien supérieur ladinien inférieur (mittlerer salvatoredolomit, gervillienhorizont) 1972a teutloporella nodosa .pantiê, pl. v, fig. 4; pl. x, fig. 2-3.forage sb-2, rivière piva, mratinje, monténégro (yougoslavie): ladinien 1973 (?) t e u t l o p o r e l l a aff. n o d o s a .popa & dragastan, pl. iii, fig. 12.e vǎii iadului, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à d a d o c r i n u s communis) 1974 teutloporella nodosa .assereto & monod, fig. 12.b.seydisehir-tarasçi, w taurus (turquie): ladinien inférieur (calcaire d’emir kaya) 1974 teutloporella nodosa .pantiê, pl. iii, fig. 2.koprivnik, krπ »vrlje, prokletije mts, kosovo, serbie (yougoslavie): ladinien 1975 “problematikum”.mello, pl. vi, fig. 6.n silica, silická planina, slovenský kras (slovaquie): ladinien (wettersteinkalk) 1975 teutloporella nodosa.pantiê-prodanoviê, pl. xlv, fig. 1 pars.©ljivovica, tara mt, w serbie (yougoslavie): ladinien 1978 teutloporella nodosa .anelkoviê, pl. lxix, fig. 4, extrait de herak (1965: pl. iii, fig. 2) 1978 teutloporella nodosa .e. flügel, pl. 25 pars.amtmanngalgen, johnsbach, gesäuse, steiermark (autriche): ladinien (wettersteinkalk) 1978 non teutloporella nodosa [= diplopora annulata ].e. flügel, pl. 22, fig. 5 1979 diplopora nodosa emend.de castro, fig. 2.a, extrait de schafhäutl (1863: pl. lxv.e, fig. 19-20); fig. 2.b, extrait de gümbel (1872: pl. d.iii, fig. 8.a-c); fig. 2.c, extrait de salomon (1895: pl. i, fig. 6.a-b, 7.a-c, 8.a-b, 9.a-b, 10.a-c, 11.a-b, 12 & 12.a); pl. i, fig. 1-7; pl. ii, fig. 1-9; pl. iii, fig. 1-13; pl. iv, fig. 112; pl. v, fig. 1-10; pl. vi, fig. 1-9; pl. vii, fig. 1-9; pl. viii, fig. 1-4; pl. ix, fig. 1-4; pl. x, fig. 1-3; pl. xi, fig. 1-8; pl. xii, fig. 1-6; pl. xiii, fig. 1-5; pl. xiv, fig. 1-6; pl. xv, fig. 1-5; pl. xvi, fig. 1-7; pl. xvii, fig. 1-2; pl. xix; pl. xx.il castello, s marsico nuevo, basilicata (italie): trias moyen; pl. xvi44 geologia croatica 53/1 ii.d’après barattolo & de castro (1991): il castello, s marsico nuevo, basilicata (italie): anisien p.p. ladinien 1980 teutloporella nodosa .dragastan, pl. vi, fig. 1, extrait de diaconu & dragastan (1969: pl. i, fig. 2); pl. vi, fig. 3, extrait de diaconu & dragastan (1969: pl. ii, fig. 1); pl. vi, fig. 5 pars.glimeia, pǎd u r e a craiului, apuseni mts, bihor (roumanie): ladinien; pl. vi, fig. 11.brǎtcuţa, pǎdurea craiului, apuseni mts, bihor (roumanie): ladinien; pl. vii, fig. 3.forage sterpinoasa, pǎdurea craiului, apuseni mts, bihor (roumanie): ladinien 1982 algae.farabegoli & levanti, pl. 6, fig. 1.mte tuglia, sappada, véneto (italie): anisien, illyrien supérieur 1982 teutloporella nodosa .fenninger, fig. 1.gartnerkofel, s hermagor, kärnten (autriche): ladinien (schlerndolomit) 1982 teutloporella nodosa .e. flügel, pl. 33 pars, extrait de e. flügel (1978: pl. 25 pars) 1982 diplopora nodosa .veliê & sokaë, pl. iii, fig. 2 pars & 3-4.poloj, w kordun, sw karlovac (croatie): anisien 1984 teutloporella nodosa .guπiê et al., fig. 6.6.karaburun, nw izmir (turquie): ladinien 1985 teutloporella nodosa .farabegoli et al., pl. 5.a.clap forat, pietratagliata, pontebba / pontafel dogna, friuli venezia giulia (italie): anisien, pelsonien (fm di agordo) 1987 teutloporella nodosa .braga & martin, pl. i, fig. 4.sierra de baza, gor baza, granada (espagne): anisien-ladinien 1988 teutloporella nodosa .pfeiffer, pl. 11, fig. 1.gartnerkofel, s hermagor, kärnten (autriche): ladinien, fassanien (schlerndolomit) 1988 diplopora nodosa .sartorio & venturini, p. 54, haut & bas.lagonegro, basilicata (italie): ladinien 1989 teutloporella nodosa .buëek, pl. ii, fig. 6.nw trstín, malé karpaty (slovaquie): ladinien (wettersteinkalk) 1990 teutloporella nodosa .ciarapica et al., fig. 2.b.la cercharia, ne brienza sw potenza, basilicata (italie): ladinien (monte facito fm) 1991 diplopora nodosa .barattolo, pl. iii, fig. 5.il castello, s marsico nuevo, basilicata (italie): trias moyen 1991 diplopora nodosa .barattolo & de castro, pl. xiv, extrait de de castro (1979: pl. xviii) 1995 teutloporella nodosa .pantiê-prodanoviê, pl. vi, fig. 8.podravno, w srebrenica (bosnie-herzégovine): ladinien diplopora nodosa var. elliptica salomon 1895 [variété superflue ] diplopora oregonensis e. flügel et al. 1989 1989 diplopora oregonensis n. sp.e. flügel et al., fig. 2, 3.1-7 & 4.1-3.wallowa mts, oregon (états-unis d’amérique): trias supérieur (hurwal fm).holotype: fig. 3.1, lame mince n° rg-1a, umip 10012, university of montana paleontological museum, missoula (états-unis d’amérique) diplopora orientalis endo 1957 1957 diplopora orientalis n. sp.endo, pl. 41, fig. 2.arito, taishaku-mura, hiba-gun, hiroshima-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie supérieure); pl. 41, fig. 3.zenbutsuji-dani, taishaku-mura, hiba-gun, hiroshima-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie supérieure).“type” (syntypes): pl. 41, fig. 2, lame mince n° 571; pl. 41, fig. 3, lame mince n° 563, department of earth sciences, saitama university, urawa (japon) diplopora panormitana p. di stefano 1981 [synonyme postérieur de diplopora borzai bystrický 1978, d’après p. di stefano & senowbari-daryan, 1985 ] 45granier & grgasoviê: les algues dasycladales du permien et du trias... diplopora permiana endo 1969 1969 diplopora permiana n. sp.endo, pl. xxxv, fig. 2-6.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à c a n c e l l i n a zone à neoschwagerina simplex / partie inférieure).holotype: pl. xxxv, fig. 2, lame mince n° gk.d 13659, kyūshū university, fukuoka (japon) 1992 (?) diplopora cf. permiana .vachard et al., pl. iii, fig. 10 pars.n ban na wai, nw thaïlande (thaïlande): murghabien supérieur midien diplopora permica kordé 1965 1965 diplopora permica n. sp.kordé, pl. liv, fig. 8.dorasham 2, dzhul’fa, nakhichevan’ (azerbaïdjan): djulfien; pl. liv, fig. 9 & 11.chanakhchi (arménie): djulfien.holotype: pl. liv, fig. 8, lame mince n° 2307/13, collection k.b. kordé, moscou (fédération de russie) 1980 diplopora permica .lys in lys et al., pl. 1, fig. 6-7.lamayuru, ladakh (inde): djulfien (zone à coloniella parva ) 1988b diplopora permica .lys, pl. xv, fig. 6-7, extrait de lys et al. (1980: pl. 1, fig. 6-7) diplopora phanerospora pia 1920 1920 diplopora phanerospora n. sp.pia, pl. iv, fig. 1-10.chemin du palmwand, bad oberdorf, hindelang, s kempten, bayern (allemagne): trias supérieur, ? rhétien (? kössener schichten).types: pl. iv, fig. 1-10, lame mince n° xcvii/1a (? xcviia/1); collection j. von pia, naturhistorisches museum, wien (autriche) 1930 diplopora phanerospora .pia, pl. 4, fig. 10, extrait de pia (1920: pl. iv, fig. 9); pl. 4, fig. 11, extrait de pia (1920: pl. iv, fig. 10); pl. 4, fig. 12, extrait de pia (1920: pl. iv, fig. 4) 1941a diplopora phanerospora .pia, fig. 11, extrait de pia (1920: pl. iv, fig. 1, 3, 7 & 9-10) 1 9 5 2 a non diplopora phanerospora .endo, pl. 12, fig. 2.sakamotozawa, hikoroichi-mura, kesen-gun, iwateken, honshū (japon): permien “inférieur” 1961 diplopora phanerospora .johnson, pl. 52, fig. 1, extrait de pia (1920: pl. iv, fig. 2) 1964 non diplopora cf. phanerospora [= ? diplopora tubispora ].bystrický, pl. xxx, fig. 8 1967 d i p l o p o r a p h a n e r o s p o r a .ott, pl. 12, fig. 1-3.kotalm, wendelstein, bayern (allemagne): rhétien (kössener schichten).“lectotype” (syntypes): lame mince n° xcvii/1a, recélant plusieurs spécimens, collection j. von pia, naturhistorisches museum, wien (autriche) 1969 (?) diplopora cf. p h a n e r o s p o r a .diaconu & dragastan, pl. vi, fig. 4.dealul glimeia, apuseni mts (roumanie): ladinien 1971 d i p l o p o r a p h a n e r o s p o n g i a [s i c].elliott, pl. 118, fig. 5.(oman): trias supérieur remanié dans du crétacé supérieur (hawasina fm) 1972 (?) diplopora cf. phanerospora .e. flügel, pl. 1, fig. 2.hinterer gosausee, gosaukamm, dachsteingruppe, oberösterreich (autriche): norien-rhétien (dachsteinkalk) 1974 diplopora phanerospora .glennie et al., fig. 4.4.21a-b.(oman): trias supérieur (mayhah fm) 1975 d i p l o p o r a cf. d. phanerospora .e. flügel, pl. 4, fig. 5.hinterer gosausee, gosaukamm, dachsteingruppe, oberösterreich (autriche): norien supérieur rhétien (dachsteinkalk) 1978 (?) d i p l o p o r a cf. p h a n e r o s p o r a .bousquet et al., pl. iii, fig. 4 pars.timpone del convento, s campo tenese, e mormanno, calabria (italie): norien 1978 diplopora phanerospora .e. flügel, pl. 5, fig. 4, extrait de e. flügel (1975: pl. 4, fig. 5) 1980 diplopora phanerospora .senowbari-daryan, pl. 13, fig. 6 & 8.feichtenstein, hintersee, salzburg (autriche): rhétien supérieur 1981 (?) d i p l o p o r a cf. p h a n e r o s p o r a .e. flügel, fig. 10.c.hinterer gosausee, gosaukamm, dachsteingruppe, oberösterreich (autriche): trias supérieur 1981 non diplopora cf. d. phanerospora [= diplopora tubispora ].sadati, pl. 59, fig. 4 1982 diplopora phanerospora .e. flügel, pl. 5, fig. 5, extrait de e. flügel (1975: pl. 4, fig. 5) 1982 diplopora phanerospora .mu, pl. xi, fig. 1-4.xizang / tibet (chine populaire): trias supérieur 1982 (?) diplopora cf. d. phanerospora .senowbari-daryan et al., pl. 23, fig. 5.cozzo di lupo, torretta, s carini, w palermo, sicile (italie): norien 46 geologia croatica 53/1 1986 non diplopora aff. phanerospora [= diplopora tubispora ].bystrický, pl. vi, fig. 5 1988 holosporella [sic].deloffre, pl. 4, fig. 6, extrait de pia (1920: pl. iv, fig. 9); pl. 4, fig. 7, extrait de pia (1920: pl. iv, fig. 10) 1993 diplopora phanerospora .senowbari-daryan & e. flügel, pl. 8, fig. 2; pl. 9, fig. 4.feichtenstein, hintersee, salzburg (autriche): rhétien supérieur diplopora philosophi (pia 1912) 1920 [cf. kantia philosophi pia 1912, emend. güvenç 1979 ] diplopora philosophi var . exuberans pia 1942, nom. nud. [= diplopora exuberans pia ex zorn 1974, nom. nud. ] diplopora porosa schafhäutl 1863 [synonyme postérieur de diplopora annulata (schafhäutl 1853) 1863, d’après pia, 1912 ] diplopora praecursor pia 1920, emend. hurka et schmid 1971 [cf. kantia praecursor (pia 1920) güvenç 1979 ] diplopora proba pia 1935 1935a diplopora proba n. sp.pia, pl. v, fig. 1.w trebeviê, s sarajevo (bosnie-herzégovine): anisien, hydaspien supérieur pelsonien.type: pl. v, fig. 1, lame mince n° 557a (1), collection j. von pia, naturhistorisches museum, wien (autriche) 1964 (?) diplopora cf. proba .bystrický, pl. xxii, fig. 9.zakázané, silická planina, slovenský kras (slovaquie): anisien, illyrien inférieur ? 1986 (?) diplopora aff. p r o b a .bystrický, pl. iii, fig. 5.zakázané, silická planina, slovenský kras (slovaquie): anisien, pelsonien terminal illyrien inférieur (physoporella pauciforata oligoporella pilosa a s s e mblage zone) 1991 (?) d i p l o p o r a aff. p r o b a .bucur, pl. 42, fig. 18.dealul redut sasca montana, resita, caraşs e v e r i n (roumanie): anisien moyen 1994 (?) d i p l o p o r a sp. cf. d i p l o p o r a p r o b a .bucur et al., pl. 10, fig. 2 pars; pl. 13, fig. 7 & 11.sasca zone, c a r aş-severin (roumanie): anisien, pelsonien-illyrien inférieur (sasca fm, valea susara limestone member) diplopora pseudoseptata endo 1968, nom. nud. 1968b (nom. nud.) diplopora pseudoseptata n. sp.endo, “chart”, non figurée.type non figuré diplopora pusilla kochansky et herak 1960 [cf. eovelebitella pusilla (kochansky et herak 1960) vachard 1974 ] diplopora rauffi ahlburg 1906 [synonyme postérieur de diplopora annulata (schafhäutl 1853) 1863, d’après pia, 1920 ] diplopora septemtrionalis (pia 1920) güvenç 1979, nom. nud. [illégitime car il fait double emploi avec diplopora annulata (schafhäutl 1853) 1863 ] diplopora ? serialis pia 1935 1935a diplopora ? serialis n. sp.pia, pl. iv, fig. 7.nw blizanac, trebeviê, s sarajevo (bosnie-herzégovine): anisien, pelsonien-illyrien (bulogkalk).type: pl. iv, fig. 7, lame mince n° 555a (1), collection j. von pia, naturhistorisches museum, wien (autriche) 1964 (?) d i p l o p o r a cf. s e r i a l i s .bystrický, pl. xxiv, fig. 3.zakázané, silická planina, slovenský kras (slovaquie): anisien, illyrien inférieur 1993 (?) diplopora ? cf. diplopora serialis (sic, dans la légende des figures, devient macroporella alpina dans le 47granier & grgasoviê: les algues dasycladales du permien et du trias... texte).senowbari-daryan et al., pl. 56, fig. 15 & 17.valdáora / olang, pusteria / pustertal, trentino alto adige (italie): anisien supérieur 1994 (?) d i p l o p o r a sp. cf. d i p l o p o r a s e r i a l i s .bucur et al., pl. 13, fig. 12.sasca zone, caraşs e v e r i n (roumanie): anisien, pelsonien-illyrien inférieur (sasca fm, valea susara limestone member) diplopora silesiaca (gümbel 1872) assman 1926 [synonyme postérieur de diplopora nodosa schafhäutl 1863, emend. de castro 1979 et/ou de diplopora annulata (schafhäutl 1853) 1863, d’après pia, 1920 ] diplopora subtilis pia 1935 [cf. kantia ? subtilis (pia 1935) güvenç 1979 ] diplopora subtilis forma typica pia 1935, nom. nud. [cf. kantia ? subtilis var . subtilis (pia ex bystricky´ 1964) güvenç 1979 ] diplopora subtilis var. calicina pia 1935 [cf. kantia ? subtilis var. calicina (pia 1935) güvenç 1979 ] diplopora subtilis var . dissocladelloidea pia 1935 [cf. kantia ? subtilis var . dissocladelloidea (pia 1935) güvenç 1979 ] diplopora subtilis var . graeca herak 1967 [cf. kantia ? subtilis var . graeca (herak 1967) güvenç 1979 ] diplopora subtilis var . subtilis pia ex bystricky´ 1964 [cf. kantia ? subtilis var . subtilis (pia ex bystricky´ 1964) güvenç 1979 ] diplopora thailandensis endo 1969, nom. nud. 1969 (nom. nud.) diplopora thailandensis n. sp.endo, pl. xx, fig. 7; pl. xxxiv, fig. 7; pl. xxxv, fig. 1.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien inférieurmoyen (rat buri limestone, zone à m i s e l l i n a zone à neoschwagerina simplex / partie inférieure). type non désigné: pl. xx, fig. 7, lame mince n° gk.d 13905; pl. xxxiv, fig. 7, lame mince n° gk.d 13903; pl. xxxv, fig. 1, lame mince n° gk.d 13754; kyūshū university, fukuoka (japon) diplopora tibetica mu 1982 1982 d i p l o p o r a t i b e t i c a n. sp.mu, pl. xi, fig. 5-7.xizang / tibet (chine populaire): permien “inférieur” / partie supérieure.holotype: pl. xi, fig. 6, lame mince n° pb8093, nanjing institute of geology and paleontology, academia sinica, nanjing (chine populaire) diplopora triasina (schauroth 1859) tornquist 1900 [cf. euteutloporella triasina (schauroth 1859) de castro 1993 ] diplopora tubispora ott 1967 1964 (?) d i p l o p o r a cf. p h a n e r o s p o r a .bystrický, pl. xxx, fig. 8.bleskový pramen, drnava, slovenský k r a s (slovaquie): norien, sévatien 1967 diplopora tubispora n. sp.ott, pl. 12, fig. 4-6.hoher göll, berchtesgaden, bayern (allemagne): norien-rhétien (dachsteinkalk).holotype: pl. 12, fig. 4, lame mince n° a 167 a/67, collection e. ott, bayerischen staatssammlung für paläontologie und historische geologie, münchen (allemagne) 1967b diplopora muranica n. sp.bystrický, pl. xvii, fig. 3-8; pl. xviii, fig. 1-8.n muráňska huta, m u r áňska planina (slovaquie): ? norien terminal rhétien basal.holotype: pl. xviii, fig. 7, lame mince n° 2926, collection j. bystrick ý, geological institute, slovak academy of sciences, bratisla va (slovaquie) 48 geologia croatica 53/1 1968 physoporella minutula .bilgütay, pl. iii, fig. 11.plackles, hohe wand, niederösterreich (autriche): rhétien 1972 (?) d i p l o p o r a cf. t u b i s p o r a .e. flügel, pl. 1, fig. 2.gosaukamm, dachsteingruppe, oberösterreich (autriche): norien (dachsteinkalk) 1975 diplopora tubispora .e. flügel, pl. 4, fig. 8.amorgós, kikládhes (grèce): trias supérieur 1977 diplopora tubispora .abate et al., fig. 5 pars.cozzo di lupo, torretta, s carini, w palermo, sicile (italie): trias supérieur 1977 (?) diplopora cf. d. tubispora .abate et al., fig. 4 pars.cozzo di lupo, torretta, s carini, w palermo, sicile (italie): trias supérieur 1979 diplopora tubispora .e. flügel, pl. 2, fig. 8.gosaukamm, dachsteingruppe, oberösterreich (autriche): norien supérieur (dachsteinkalk) 1980 (?) diplopora tubispora .dragastan, pl. vi, fig. 1, 3, 5 pars & 7 pars.glimeia, pǎdurea craiului, apuseni mts, bihor (roumanie): ladinien 1980b diplopora tubispora .dullo, pl. 10, fig. 11.schildmauer, sw gesäuse, steiermark (autriche): trias supérieur (dachsteinkalk) 1980 diplopora tubispora .senowbari-daryan, pl. 13, fig. 5.feichtenstein, hintersee, salzburg (autriche): rhétien supérieur 1980 (?) diplopora sp.senowbari-daryan, pl. 14, fig. 7.feichtenstein, hintersee, salzburg (autriche): rhétien supérieur 1981b diplopora tubispora .p. di stefano in catalano & d’argenio, fig. 28.f.cozzo di lupo, torretta, s carini, w palermo, sicile (italie): norien 1981 diplopora cf. d. phanerospora .sadati, pl. 59, fig. 4.hohe wand, niederösterreich (autriche): norien supérieur rhétien inférieur (dachsteinkalk) 1982 diplopora tubispora .wurm, pl. 33, fig. 7.gosaukamm, dachsteingruppe, oberösterreich (autriche): norien (dachsteinkalk) 1985 diplopora tubispora .p. di stefano & senowbari-daryan, fig. 7 pars; pl. vii, fig. 1-4.cozzo di lupo, torretta, s carini, w palermo, sicile (italie): norien 1986 diplopora aff. phanerospora .bystrický, pl. vi, fig. 5.bleskový pramen, drnava, slovenský kras (slovaquie): rhétien (heteroporella taxon-range superzone) 1986 diplopora muranica .bystrický, pl. vi, fig. 4.muráňska planina (slovaquie): rhétien (skalka limestone, heteroporella taxon-range superzone) 1988 diplopora muranica .»anoviê & kemenci, pl. xxvi, fig. 1.forage bajπa-2 (ba-2), bajπa, vojvodina, serbie (yougoslavie): norien-rhétien remanié dans du tertiaire 1991 d i p l o p o r a sp.röhl et al., pl. 59, fig. 1.odp leg 122, wombat plateau, offshore nw australia (australie): rhétien 1993 d i p l o p o r a t u b i s p o r a .senowbari-daryan & e. flügel, pl. 8, fig. 3.feichtenstein, hintersee, salzburg (autriche): rhétien supérieur 1993 (?) d i p l o p o r a sp.senowbari-daryan & e. flügel, pl. 8, fig. 1.feichtenstein, hintersee, salzburg (autriche): rhétien supérieur 1996 diplopora tubispora .bernecker, pl. 12, fig. 1.jabal wasa (oman): norien-rhétien diplopora uniserialis pia 1920, emend. güvenç 1979 [= diplopora uniserialis (forma trichophora) pia 1920 ] 1920 diplopora uniserialis n. sp. (forma trichophora).pia, pl. v, fig. 2 & 6.rothorn, diemtigtal, bern (suisse): anisien; pl. v, fig. 3.chable-croix, trévenensaz-masse, muraz vionnaz, valais (suisse): anisien.types: pl. v, fig. 2 & 6, lames minces n° ?, collection j. von pia, naturhistorisches muse um, wien (autriche) 1933 diplopora annulata var. briançonnensis n. var. forma trichophora.schneegans, pl. i, fig. 2-3; pl. ii, fig. 1-2 & 5-8.rocher de la tête noire, ne val des prés (france): trias moyen.types: pl. i, fig. 1-6; pl. ii, fig. 1-8 & 12-14 1933 (?) diplopora annulata var. briançonnensis n. var.schneegans, pl. i, fig. 4-5; pl. ii, fig. 13-14.rocher de la tête noire, ne val des prés (france): trias moyen; pl. i, fig. 6.col de l’izoard, arvieux, hautesalpes (france): trias moyen; pl. ii, fig. 12.grand galibier, savoie (france): trias (galet de la brèche triasique) 49granier & grgasoviê: les algues dasycladales du permien et du trias... 1969 diplopora uniserialis .bloch & lefevre, pl. i, fig. 4-6 & 13-14.val de preit, bric bernoir, col del mulo-passo della gardetta, bersezio, piemonte (italie): ladinien 1 9 6 9 (nom. nud.) diplopora uniserialis var. l i g u r i c a n. var.bloch in bloch & lefevre, p. 1167, non figurée. type non désigné 1969 diplopora uniserialis emend.güvenç, p. 630, non figurée diplopora uniserialis (forma trichophora) pia 1920 [cf. diplopora uniserialis pia 1920, emend. güvenç 1979 ] diplopora uniserialis (forma vesiculifera) pia 1920 [cf. kantia uniserialis (pia 1920) güvenç 1979 ] diplopora uniserialis var . brianconnensis (schneegans 1933) bloch in bloch et lefevre 1969, nom. nud. [variété superflue; cf. kantia uniserialis (pia 1920) güvenç 1979 ] diplopora uniserialis var . ligurica bloch in bloch et lefevre 1969, nom. nud. [cf. diplopora uniserialis pia 1920, emend. güvenç 1979 ] diplopora vicentina tornquist 1899 [cf. teutloporella vicentina (tornquist 1899) pia 1912 ] diplopora yoshinobensis ishijima et al. 1971 1971 diplopora yoshinobensis n. sp.ishijima et al., pl. 13, fig. 1; pl. 15, fig. 1-2.sakaishimachibun, hannōshi, saitama-ken, honshū (japon): permien “inférieur”.holotype: pl. 15, fig. 1, spécimen n° nsmp118072a, national science museum, tokyo (japon) dissocladella pia in l.r. rao et pia 1936, emend. bassoullet et al. 1978 dissocladella bystrickyi soka» et grgasovi∆ 1995 1995 dissocladella bystrickyi n. sp.sokaë & grgasoviê, pl. i, fig. 1-11; pl. ii, fig. 1-11.gornje vrapëe, sw medvednica mt, w zagreb (croatie): norian-rhaetian (dolomia principale / hauptdolomit).holotype: pl. i, fig. 7, échantillon vr-1a/9, collection b. sokaë, institut za geoloπka istraæivanja [institute of geology], zagreb (croatie) dvinella khvorova 1949 dvinella subg. dvinella maslov et kulik ex kulik 1964 *dvinella (dvinella) comata khvorova 1949 1949 dvinella comata n. sp.khvorova, fig. 1-2.arkhangel’sk (fédération de russie): carbonifère, silésien, moscovien, podolskien.holotype: fig. 1 [= pl. 11, fig. 13 in roux (1979a); = pl. 11, fig. 13 in mamet et al. (1987)], lame mince n° cgc 61009, lame mince n° 1071, collection i.v. khvorova, institut de paléontologie, académie des sciences de l’urss, moscou (fédération de russie) 1950 dvinella comata .kordé, fig. 1-2.moskva (fédération de russie): carbonifère “moyen” 1956 dvinella comata.johnson & konishi, pl. 9, fig. 4, extrait de kordé (1950: fig. 1) 1956 non dvinella comata [= beresella ex gr. polyramosa].maslov, pl. xiii, fig. 1-2 & 5; pl. xix, fig. 2 1958 dvinella.lys & serre, pl. i, fig. 3.covadonga, asturias (espagne): carbonifère, silésien, westphalien a (calcaire de rivadesella, zone “supérieure” à fusulinella böcki et var. d e l e p i n e i); pl. iv, fig. 2 pars; pl. vi, fig. 4 pars.arriondas cofino, asturias (espagne): carbonifère, silésien, westphalien a (cal50 geologia croatica 53/1 caire de rivadesella, zone “supérieure” à fusulinella böcki et var. d e l e p i n e i); pl. v, fig. 5 pars.camarmeña arenas de calabres, asturias (espagne): carbonifère, silésien, westphalien a (calcaire de rivadesella, zone “supérieure” à fusulinella böcki et var. delepinei) 1 9 6 1 a non dvinella comata [= beresella ex gr. p o l y r a m o s a].endo, pl. 8, fig. 5, extrait de endo & horiguchi (1957: pl. xiii, fig. 4) 1961c dvinella comata divinella comata [s i c].endo, pl. 7, fig. 4.sayama-managatake, agako, mitōc hō, ne mine-shi, yamaguchi-ken, honshū (japon): permien inférieur (akiyoshi limestone group, zone à pseudoschwagerina , sous-zone à triticites simplex) 1963 dvinella comata.herak & kochansky, pl. ii, fig. 1-4.nagyberenás, bükk hegység (hongrie): carbonifère, silésien, moscovien supérieur 1963 dvinella.herak, fig. 36, extrait de herak & kochansky (1963: pl. ii, fig. 1) 1963 non dvinella comata [= beresella ex gr. p o l y r a m o s a].johnson, pl. 12, fig. 1, extrait de maslov (1956: pl. xiii, fig. 2); pl. 12, fig. 2, extrait de maslov (1956: pl. xix, fig. 2); pl. 12, fig. 3, extrait de maslov (1956: pl. xiii, fig. 5); pl. 13, fig. 1 1963 non dvinella comata .maslov in bakhrameeba et al., pl. xv, fig. 3.(fédération de russie): carbonifère 1964 dvinella (d v i n e l l a) c o m a t a.kulik, pl. viii, fig. 11.sivin’, w saransk, mordovskaya (fédération de russie): carbonifère, silésien, moscovien, podolskien 1964 dvinella (d v i n e l l a) c o n i f o r m i s n. sp.kulik, fig. 3.c.samarskaya, w kuybyshev (fédération de russie): carbonifère, silésien, moscovien.holotype: fig. 3.c, lame mince n° 3438/19, collection e.l. kulik, geologicheski institut akademije nauk sssr (fédération de russie) 1964 non dvinella comata.rácz, pl. iii, fig. 1-2.león (espagne): carbonifère, silésien, moscovien inférieur (fm lois-ciguera, zone à profusulinella , sous-zone b; zone à fusulinella , sous-zone a) 1967 non dvinella comata [= beresella ex gr. polyramosa].rich, pl. 125, fig. 1-2, 4, 11, 14, 15 pars & 17 1971 dvinella comata .de meijer, pl. xiii, fig. 8 pars; pl. xv, fig. 6, 7 pars & 8 pars.león (espagne): carbonifère, silésien, moscovien (fm lois-ciguera) 1971 (?) dvinella a f f . c o m a t a.perret, pl. xxx, fig. 1.a-b.nw areng, hautes-pyrénées (france): carbonifère, dinantien, viséen supérieur 1978 dvinella comata .lys et al., pl. 3, fig. 19.ramian, e elbourz (iran): carbonifère, silésien, moscovien, véreiskien 1979a dvinella comata .roux, pl. 11, fig. 12.girty creek, ellesmere, nunavut (canada): carbonifère, silésien, moscovien moyen ou plus jeune (fm nansen); pl. 11, fig. 13, extrait de khvorova (1949: fig. 1); pl. 11, fig. 14.hare fiord, ellesmere, nunavut (canada): carbonifère, silésien, moscovien moyen ou plus jeune (fm otto fiord); pl. 11, fig. 15-18.n otto fiord, ellesmere, nunavut (canada): carbonifère, silésien, moscovien moyen ou plus jeune (fm nansen) 1979 dvinella comata .zagorodnjuk, pl. ii, fig. 7.bashkirskaya (fédération de russie): carbonifère, silésien, moscovien 1987 dvinella comata.mamet et al., pl. 11, fig. 12-18, extrait de roux (1979a: pl. 11, fig. 12-18) 1988 dvinella comata .e. flügel & kahler, pl. 20, fig. 3.s belemedik, nigde (turquie): carbonifère, silésien, moscovien, podolskien; pl. 18, fig. 6 pars; pl. 20, fig. 4.belemedik, nigde (turquie): carbonifère, silésien, moscovien, podolskien 1988b dvinella comata .lys, pl. viii, fig. 19, extrait de lys et al. (1978: pl. 3, fig. 19) dvinella (dvinella) coniformis kulik 1964 [synonyme postérieur de dvinella (dvinella) comata khvorova 1949, d’après mamet et roux in mamet et al. , 1987] dvinella subg. trinodella maslov et kulik ex kulik 1964 *dvinella (trinodella ) bifurcata maslov et kulik ex kulik 1964 1956 (nom. nud.) trinodella bifurcata n. subgen. n. sp.maslov & kulik, p. 128, non figurée.type non figurée 1964 b e r e s e l l a e .glintzboeckel & rabaté, pl. xxix, fig. 1-2.forage kirchaou, s gabes (tunisie): carbonifère, silésien 51granier & grgasoviê: les algues dasycladales du permien et du trias... 1964 d v i n e l l a.glintzboeckel & rabaté, pl. xiii, fig. 1.forage kirchaou, s gabes (tunisie): carbonifère, silésien, moscovien; pl. xxix, fig. 1-2.forage kirchaou, s gabes (tunisie): carbonifère, silésien 1964 trinodella (t r i n o d e l l a) b i f u r c a t a .kulik, pl. viii, fig. 14.yulovo-ishima, e penza (fédération de russie): carbonifère, silésien, moscovien, kashirskien.holotype: pl. viii, fig. 14, lame mince n° 3438/22, collection e.l. kulik, geologicheski institut akademije nauk sssr (fédération de russie) 1979 dvinella bifurcata .mamet et al., pl. 3, fig. 2 pars.girty creek, ellesmere, nunavut (canada): carbonifère, silésien, moscovien moyen ou plus jeune (fm nansen) 1979a dvinella bifurcata .roux, pl. 11, fig. 7; pl. 12, fig. 1-3, 5-8, 11, 14, 17-18, 20 & 23.girty creek, ellesmere, nunavut (canada): carbonifère, silésien, moscovien moyen ou plus jeune (fm nansen); pl. 12, fig. 4.glacier de wood, ellesmere, nunavut (canada): carbonifère, silésien, moscovien moyen ou plus jeune (fm otto fiord); pl. 12, fig. 12.griesbach, axel heiberg, nunavut (canada): permien (fm nansen); pl. 12, fig. 13.n otto fiord, ellesmere, nunavut (canada): sakmarien (fm nansen); pl. 12, fig. 16.glacier de wood, ellesmere, nunavut (canada): carbonifère, silésien, bashkirien, kayalien ou plus jeune (fm otto fiord); pl. 12, fig. 19.baie d’oobloyah, ellesmere, nunavut (canada): carbonifère, silésien (fm nansen); pl. 12, fig. 21.n col van hauen, ellesmere, nunavut (canada): carbonifère, silésien, bashkirien (fm otto fiord); pl. 12, fig. 22.griesbach, axel heiberg, nunavut (canada): sakmarien (fm nansen) 1987 dvinella bifurcata .mamet et al., pl. 11, fig. 7, extrait de roux (1979a: pl. 11, fig. 7); pl. 12, fig. 1-8 & 11-23, extrait de roux (1979a: pl. 12, fig. 1-8 & 11-23) embergerella güvenç 1972, nom. nud. [illégitime car c’est un homonyme postérieur de embergerella grambast 1969, charophytes ] *embergerella anatoliana güvenç 1972, nom. nud. 1965 dasycladaceae indét. sp. 1.güvenç, pl. a8, fig. 1.vallée du dikenli dere, alanya (turquie): permien “inférieur” terminal 1972 (nom. nud.) embergerella anatoliana n. gen. n. sp.güvenç, fig. 1, extrait de güvenç (1965: pl. a8, fig. 1); fig. 2-3.vallée du dikenli dere, alanya (turquie): permien moyen, darvasien.holotype: fig. 1 & 3, lame mince n° tg-401, collection t. güvenç, ankara (turquie) 1988 (nom. nud.) embergerella anatoliana .deloffre, pl. 3, fig. 4, extrait de güvenç (1965: pl. a8, fig. 1) endoina kordé 1965 *endoina stellata kordé 1965 1965 endoina stellata n. gen. n. sp.kordé, pl. lvii, fig. 1, 2.a-c & 3.a-b.avush, nakhichevan’ (azerbaïdjan): guadalupien.holotype: pl. lvii, fig. 1, lame mince n° 2307/33, collection k.b. kordé, moscou (fédération de russie) eoclypeina emberger ex vachard 1985, non poncet 1987 *eoclypeina embergeri vachard 1985 1964 (nom. nud.) “eoclypeina”.glintzboeckel & rabaté, pl. lxxiv, fig. 2; pl. lxxxiii, fig. 1-2.djebel tebaga (tunisie): permien supérieur (zone à y a b e i n a); pl. lxxv, fig. 1-2; pl. lxxix, fig. 1 pars; pl. lxxxiv, fig. 2; pl. lxxxv, fig. 1-2.djebel tebaga (tunisie): permien “supérieur” 1965 (?) diploporidae.güvenç, pl. m.17, fig. 1 pars.w taurus (turquie): permien “supérieur” terminal 1977 non (nom. nud.) eoclypeina sp.vachard in h. termier et al., pl. 2, fig. 8.djebel tebaga (tunisie): murghabien (calcaires à bellerophon); pl. 2, fig. 9.djebel tebaga (tunisie): murghabien (dolomies inférieures et marnes du chabet n guer) 52 geologia croatica 53/1 1985 eoclypeina embergeri n. gen. n. sp.vachard, pl. 1, fig. 2, 5 & 8-9; pl. 2, fig. 1-4.djebel tebaga (tunisie): murghabien supérieur.holotype: pl. 2, fig. 3, lame mince n° ab 16d, collection d. vachard, igal, paris (france); paratypes: pl. 1, fig. 2; pl. 2, fig. 4, lame mince n° ab 16d; pl. 1, fig. 5, lame mince n° ab 16e; pl. 1, fig. 8-9, lame mince n° ab 16b; pl. 2, fig. 1-2, lame mince n° ab 16f, collection j.-p. bassoullet 1985 eoclypéines.vachard, pl. 1, fig. 4 pars.djebel tebaga (tunisie): murghabien supérieur 1988 eoclypeina embergeri .vachard & razgallah, pl. 1, fig. 24.djebel tebaga (tunisie): murghabien “terminal” (zone à neoschwagerina et yabeina) 1993 eoclypeina embergeri.vachard & razgallah, pl. 1, fig. 4.2.djebel tebaga (tunisie): murghabien supérieur (zone à neoschwagerina, yabeina et dunbarula , sous-zone à dunbarula nana ) eogoniolina endo 1953 [synonyme postérieur de mizzia schubert 1909, emend. rezak 1959, d’après vachard, 1980 ] eogoniolina endoi nakamura et chisaka 1984 1984 eogoniolina endoi n. sp.nakamura & chisaka, pl. 6, fig. 8-9.mt atagoyama, chôshi-shi, chiba-ken, honshū (japon): permien “supérieur” (takagami conglomerate).holotype: pl. 6, fig. 8, lame mince n° nsm-pp 7910c, national science museum, tokyo (japon) *eogoniolina johnsoni endo 1953 1953b eogoniolina johnsoni n. gen. n. sp.endo, pl. ix, fig. 5-10.kinshō-zan hill, mino-akasaka, n o _ g a k i shi, gifu-ken, honshū (japon): permien moyen (zone à neoschwagerina craticulifera ).syntypes: pl. ix, fig. 5 et/ou 6 et/ou 7 & 8-9, lame mince n° 173, échantillon 10864, department of earth sciences, saitama university, urawa (japon) 1954 eogoniolina johnsoni.endo in endo & kanuma, pl. xiv, fig. 7; pl. xv, fig. 11.kayu-gawa, takedamura, gujō-gun, gifu-ken, honshū (japon): permien moyen (kayugawa fm, zone à n e o s c h w a g e r i n averbeeckina) 1956 eogoniolina johnsoni .endo, pl. 23, fig. 2-3.onokubo, okama, senpa, tokiwa-mura, aso-gun, tochigi-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie supérieure); pl. 23, fig. 4.s hōm u r a tōge pass, agano-mura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne) 1957 eogoniolina johnsoni .endo, pl. 37, fig. 2-3.zenbutsuji-dani, taishaku-mura, hiba-gun, hiroshimaken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie supérieure) 1959 eogoniolina johnsoni.endo, pl. 31, fig. 2.yokoberadani valley, hatahoko, nyūgawa-mura, o _ n o g u n , gifu-ken, honshū (japon): permien moyen (o _ zu fm, zone à n e o s c h w a g e r i n a); pl. 31, fig. 3-4; pl. 37, fig. 8.sotedani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien inférieur-moyen (gonbō fm, zone à parafusulina ) 1961c eogoniolina johnsoni .endo, pl. 5, fig. 1.yobara-w irimi, o _ mine, nw mine-shi, yamaguchi-ken, honshū (japon): permien supérieur (akiyoshi limestone group, zone à yabeina shiraiwensis); pl. 5, fig. 2.s hagiwara, ofuku, n mine-shi, yamaguchi-ken, honshū (japon): permien supérieur (akiyoshi limestone group, zone à yabeina shiraiwensis) 1963 eogoniolina johnsoni .johnson, pl. 55, fig. 2, extrait de endo (1956: pl. 23, fig. 4); pl. 55, fig. 3, extrait de endo (1957: pl. 37, fig. 2); pl. 55, fig. 4, extrait de endo (1956: pl. 23, fig. 3); pl. 55, fig. 5, extrait de endo (1956: pl. 23, fig. 2) 1964 eogoniolina johnsoni .glintzboeckel & rabaté, pl. lxxiv, fig. 2.djebel tebaga (tunisie): permien supérieur (zone à yabeina) 1965 eugoniolina johnsoni [sic].kordé, pl. liv, fig. 1.dorasham 1, dzhul’fa, nakhichevan’ (azerbaïdjan): guadalupien; pl. liv, fig. 2.dorasham 2, dzhul’fa, nakhichevan’ (azerbaïdjan): guadalupien; pl. liv, fig. 10.chanakhchi (arménie): guadalupien 1974 eogoniolina johnsoni.mu, pl. 167, fig. 4-5.sw chine (chine populaire) 1977 eogoniolina johnsoni .vachard in h. termier et al., pl. 2, fig. 6.djebel tebaga (tunisie): murghabien (dolomies inférieures et marnes du chabet n guer) 53granier & grgasoviê: les algues dasycladales du permien et du trias... 1981 eogoniolina johnsoni .nakamura, pl. 6, fig. 6-9.ishiyama, o _ n o c hō tanigumi-mura, gifu-ken, honshū (japon): permien (ishiyama limestone) 1982 eogoniolina johnsoni.mu, pl. viii, fig. 7-8.xizang / tibet (chine populaire): permien “inférieur” / partie supérieure 1985 mizzia yabei = eogoniolina johnsoni.vachard, pl. 1, fig. 1.djebel tebaga (tunisie): murghabien supérieur 1988 eogoniolina.deloffre, pl. 2, fig. 20, extrait de endo (1956: pl. 23, fig. 3) 1990 eogoniolina johnsoni .e. flügel, pl. 4, fig. 2.balya-edremit, sw balya, w balikesir (turquie): murghabien supérieur (zone à neoschwagerina / partie supérieure) 1993 (?) eogoniolina johnsoni.vachard & razgallah, pl. 2, fig. 6.4.djebel seïkra, djebel tebaga (tunisie): murghabien supérieur (zone à neoschwagerina, yabeina et dunbarula , sous-zone à dunbarula mathieui et codonofusiella) 1996 eogoniolina johnsoni.pantiê-prodanoviê, pl. i, fig. 1.gaj, vlaπiê mt, oseëina, w krupanj, serbie (yougoslavie): permien supérieur eogoniolina pamiri güvenç 1966, non 1965 1965 (nom. nud.) eogoniolina pamiri n. sp.güvenç, pl. a7, fig. 8-9.col de hortubeleni, vallée du dikenli dere, alanya (turquie): permien “supérieur”.holotype: pl. a7, fig. 8, lame mince n° t.g. ii-695, collection t. güvenç, laboratoire de micropaléontologie, faculté des sciences de paris (france) 1965 eogoniolina sp.güvenç, pl. m12, fig. 2.b.w taurus (turquie): permien “inférieur” terminal 1966b eogoniolina pamiri n. sp.güvenç, pl. 3, fig. 4, extrait de güvenç (1965: pl. a7, fig. 8); pl. 3, fig. 5, extrait de güvenç (1965: pl. a7, fig. 9).holotype: pl. 3, fig. 4, lame mince n° t.g. 11-695, collection t. güvenç, laboratoire de micropaléontologie, faculté des sciences de paris (france) eogoniolina undulata endo 1957 1957 eogoniolina undulata n. sp.endo, pl. 37, fig. 6-7.zenbutsuji-dani, taishaku-mura, hiba-gun, hiroshima-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie supérieure).syntypes: pl. 37, fig. 6, lame mince n° 544; pl. 37, fig. 7, lame mince n° 552, department of earth sciences, saitama university, urawa (japon) eomizzia endo et horiguchi 1957, nom. nud. [“synonyme” de beresella makhaev ex maslov et kulik 1956 et/ou de donezella (maslov 1929) ] *eomizzia igoi endo et horiguchi 1957, nom. nud. [“synonyme” de beresella polyramosa kulik 1964 et/ou de donezella lutugini (maslov 1929) ] eovelebitella vachard 1974, emend. mamet et roux 1983 eovelebitella media vachard in vachard et montenat 1981 [= clavaporella media vachard 1980, nom. nud. ] 1 9 8 0 (nom. nud.) clavaporella media n. comb.vachard, pl. 24, fig. 2-3 & 5.khwaja bahadur, tezak (afghanistan): kubergandien 1981 eovelebitella media n. sp.vachard in vachard & montenat, pl. 5, fig. 2, extrait de vachard (1980: pl. 24, fig. 5); pl. 5, fig. 3-5; pl. 5, fig. 9.khwaja bahadur, tezak (afghanistan): kubergandien.holotype: pl. 5, fig. 2, lame mince n° iv/452 (ml 4187); paratypes: pl. 5, fig. 3-4, lame mince n° iv/452 (ml 4187); pl. 5, fig. 5 & 9, lame mince n° iv/419, collection m. lys, institut de géologie igal, paris (france) 54 geologia croatica 53/1 eovelebitella pusilla (kochansky et herak 1960) vachard 1974 [= diplopora pusilla kochansky et herak 1960 ] 1960 diplopora pusilla n. sp.kochansky & herak, pl. ix, fig. 1-8.matkoviê, nw bar, s monténégro (yougoslavie): léonardien supérieur wordien inférieur (galets dans un conglomérat anisien).holotype: pl. ix, fig. 2, lame mince n° 1081, collection v. kochansky-devidé & m. herak, geoloπkopaleontoloπki zavod, prirodoslovno-matematiëki fakultet [geological and palaeontological institute, faculty of sciences ], zagreb (croatie) 1963 diplopora pusilla .h. flügel, pl. 1, fig. 2.dizdere, djulfa, azerbaïdjan iranien (iran): permien 1963 diplopora pusilla .johnson, pl. 54, fig. 1-8, extrait de kochansky & herak (1960: pl. ix, fig. 1-8) 1974 (?) diplopora pusila [s i c].mirkoviê, pl. viii, fig. 4.ratkovica, e monténégro (yougoslavie): permien “moyen” 1974 eovelebitella pusilla n. comb.vachard, p. 1855 & 1857, non figurée 1978 diplopora pusilla .anelkoviê, pl. xli, fig. 9, extrait de kochansky & herak (1960: pl. ix, fig. 2); pl. xli, fig. 10, extrait de kochansky & herak (1960: pl. ix, fig. 4); pl. xli, fig. 11, extrait de kochansky & herak (1960: pl. ix, fig. 7); pl. xli, fig. 12, extrait de kochansky & herak (1960: pl. ix, fig. 6); pl. xli, fig. 13, extrait de kochansky & herak (1960: pl. ix, fig. 5) 1978 diplopora pusula [sic].anelkoviê, pl. xl, fig. 2, extrait de kochansky & herak (1960: pl. ix, fig. 4) 1978 (?) eovelebitella sp.lys et al., pl. 2, fig. 1-5.tilabad, ne téhéran, e elbourz (iran): carbonifère, silésien, serpukhovien inférieur (fm de bagherabad) 1979a (?) diplopora sp. cf. p u s i l l a .roux, pl. 20, fig. 9-10.girty creek, ellesmere, nunavut (canada): carbonifère “moyen” (fm nansen) fig. 10 diplopora pusilla (kochansky & herak, 1960, pl. ix, fig. 2), x44. fig. 11 diplopora pusilla (kochansky & herak, 1960, pl. ix, fig. 8), x44. 55granier & grgasoviê: les algues dasycladales du permien et du trias... 1980 clavaporella pusilla n. comb.vachard, pl. 24, fig. 6.tezak khwaja bahadur, tezak (afghanistan): murghabien supérieur 1981 eovelebitella pusilla.vachard in vachard & montenat, pl. 5, fig. 6, extrait de vachard (1980: pl. 24, fig. 6); pl. 5, fig. 7.khwaja bahadur, tezak (afghanistan): kubergandien; pl. 14, fig. 18 pars.khwaja bahadur, tezak (afghanistan): murghabien inférieur 1987 (?) diplopora sp. cf. pusilla.mamet et al., pl. 20, fig. 9-10, extrait de roux (1979a: pl. 20, fig. 9-10) 1990 diplopora pusilla .dragastan et al., pl. i, fig. 6; pl. iii, fig. 1.sakesar, salt range (pakistan): murghabien supérieur djulfien supérieur (wargal fm) epimastopora pia ex kordé 1951, emend. roux 1979 epimastopora alpina kochansky et herak 1960, nom. nud. [cf. epimastoporella alpina kochansky et herak ex roux 1979 ] epimastopora angulata (chuvashov 1974) roux 1979 [= globuliferoporella angulata chuvashov 1974 ] 1974 globuliferoporella angulata n. sp.chuvashov, pl. xii, fig. 8-9; pl. xiii, fig. 1-3 & 5-7.w y e k a t e r i nburg, w oural (fédération de russie): assélien; pl. xiii, fig. 4 & 8.d’après chuvashov et al. (1993): bisert’ river, w yekaterinburg (fédération de russie): assélien.holotype: pl. xiii, fig. 4, lame mince n° π 208-71, collection b.i. chuvashov, unt ai sssr [institute of geology and geochemistry of urals, section of russian academy of sciences ], yekaterinburg (fédération de russie) 1979b epimastopora angulata n. comb.roux, p. 807, non figurée 1982 (?) globuliferoporella c f . a n g u l a t a .mu, pl. ix, fig. 10.xizang / tibet (chine populaire): carbonifère, silésien 1989 globuliferoporella angulata .vachard, pl. 6, fig. 10-11; pl. 9, fig. 2 pars.pulau apat, jambi province, sumatra (indonésie): assélien moyen-sakmarien (assélien supérieur probable) 1993 globuliferoporella angulata .chuvashov et al., pl. 14, fig. 18, extrait de chuvashov (1974: pl. xiii, fig. 4); pl. 14, fig. 19, extrait de chuvashov (1974: pl. xiii, fig. 8) epimastopora bashkirica kulik 1978 1978 epimastopora bashkirica n. sp.kulik, pl. v, fig. 9.shakhtau massif, bashkirskaya (fédération de russie): sakmarien, tastubien (zone à pseudofusulina moelleri, sous-zone ts1); pl. v, fig. 10.shakhtau massif, bashkirskaya (fédération de russie): assélien, kurmainskien (zone à schwagerina sphaerica et pseudofusulina firma, zone ass3).holotype: pl. v, fig. 9, lame mince n° 4513/50, collection e.l. kulik, geologicheski institut akademije nauk sssr (fédération de russie) epimastopora choshiensis nakamura et chisaka 1984 1981 epimastopora sp.nakamura, pl. 2, fig. 7.ishiyama, o _ n o c hō tanigumi-mura, gifu-ken, honshū (japon): permien (ishiyama limestone) 1984 epimastopora choshiensis n. sp.nakamura & chisaka, pl. 7, fig. 12-14.mt atagoyama, chôshi-shi, chiba-ken, honshū (japon): permien “supérieur” (takagami conglomerate).holotype: pl. 7, fig. 12, lame mince n° nsm-pp 7919a, national science museum, tokyo (japon) epimastopora densipora endo 1969 1969 epimastopora densipora n. sp.endo, pl. xlii, fig. 1-2.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à c a n c e l l i n a ). holotype: pl. xlii, fig. 1, lame mince n° gk.d 13083 (non 13293), kyū s hū university, fukuoka (japon) 1984 epimastopora densipora .e. flügel, kochansky-devidé & ramovπ, pl. 30, fig. 7.straæa, bled (slovénie): permien “moyen” 1984 epimastopora densipora .nakamura & chisaka, pl. 7, fig. 3-6.mt atagoyama, chôshi-shi, chiba-ken, honshū (japon): permien “supérieur” (takagami conglomerate) 56 geologia croatica 53/1 epimastopora fluegeli kulik 1978 1978 epimastopora flügeli n. sp.kulik, pl. v, fig. 4-5.shakhtau massif, bashkirskaya (fédération de russie): assélien, kurmainskien (zone à schwagerina sphaerica et pseudofusulina firma, zone ass3); pl. v, fig. 6.shakhtau massif, bashkirskaya (fédération de russie): sakmarien, sterlitimakien (zone à pseudofusulina urdalensis , sous-zone st2).holotype: pl. v, fig. 4, lame mince n° 4513/39-1, collection e.l. kulik, geologicheski institut akademije nauk sssr (fédération de russie) 1980 epimastopora flügeli.e. flügel & flügel-kahler, pl. 6, fig. 2.ne col mezzodì, forni avoltri, friuli venezia giulia (italie): permien inférieur (trogkofelkalk) epimastopora grandis chuvashov et anfimov 1988 1974 epimastopora sp.chuvashov, pl. ix, fig. 1.rivière chigishan, w yekaterinburg, w oural (fédération de russie): assélien 1988 epimastopora grandis n. sp.chuvashov & anfimov, pl. xxiv, fig. 1-4.sw oural (fédération de russie): moscovien supérieur.holotype (non figuré): pl. ix, fig. 1 in chuvashov (1974), lame mince n° π 208-37, collection b.i. chuvashov, unt ai sssr [institute of geology and geochemistry of urals, section of russian academy of sciences ], yekaterinburg (fédération de russie) epimastopora hexagona ishijima 1975 1975 epimastopora hexagona n. sp.ishijima, pl. 2, fig. 1-3.chôshi-shi, chiba-ken, honshū (japon): permien “supérieur” (takagami conglomerate).holotype: pl. 2, fig. 1-3, collection w. ishijima, ? st. paul’s rikkyo university, tokyo (japon) 1984 epimastopora hexagona .nakamura & chisaka, pl. 7, fig. 7-11.mt atagoyama, chôshi-shi, chiba-ken, honshū (japon): permien “supérieur” (takagami conglomerate) epimastopora hinomatensis horiguchi 1958, nom. nud. 1958 (nom. nud.) epimastopora hinomatensis n. sp.horiguchi, pl. 28, fig. 1-3.iwate-ken, honshū (japon): permien “inférieur”.“holotype” (syntypes): pl. 28, fig. 1-3, lame mince n° 11069, department of earth sciences, saitama university, urawa (japon) epimastopora hunzaensis zanin buri 1965 [cf. epimastoporella hunzaensis (zanin buri 1965) roux 1979 ] epimastopora iwaizakiensis endo 1953 [cf. epimastoporella iwaizakiensis (endo 1953) roux 1979 ] epimastopora japonica endo 1951 [cf. epimastoporella japonica (endo 1951) roux 1979 ] epimastopora kansasensis johnson 1951, non 1946 [cf. paraepimastopora kansasensis (johnson 1951) roux 1979 ] epimastopora kanumai endo in endo et kanuma 1954 [cf. paraepimastopora kanumai (endo 1954) roux 1979 ] epimastopora ketini bilgütay 1960, nom. nud. [cf. epimastoporella ketini (bilgütay 1960) roux 1979, nom. nud. ] epimastopora kosakiensis konishi 1954 [cf. epimastoporella kosakiensis (konishi 1954) roux 1979 ] epimastopora lateinterporosa endo 1961 [cf. paraepimastopora lateinterporosa (endo 1961) roux 1979 ] 57granier & grgasoviê: les algues dasycladales du permien et du trias... epimastopora likana kochansky et herak 1960 [synonyme postérieur de epimastoporella japonica (endo 1951) roux 1979, d’après mamet et roux in mamet et al. , 1987] epimastopora longituba endo 1957 [cf. paraepimastopora longituba (endo 1957) roux 1979 ] epimastopora malaysiana elliott 1968 [cf. epimastoporella malaysiana (elliott 1968) roux 1979 ] epimastopora minima elliott 1956 [espèce exclue des dasycladales, il s’agirait d’un tauridium sp., d’après elliott, 1968a ] epimastopora piae bilgütay 1960, nom. nud. 1960 (nom. nud.) epimastopora piae n. sp.bilgütay, fig. 2.a-c; pl. ii, fig. 1-4.hasanoǧlan, e ankara (turquie): permien “inférieur”.types: pl. ii, fig. 1-4, lame mince coll. n° 19, collection u. bilgütay, mineral research and exploration institute of turkey (m.t.a.), ankara (turquie) 1966 (nom. nud.) epimastopora piae .e. flügel, pl. 6, fig. 3.kärnten (autriche): permien inférieur (oberer pseudoschwagerinenkalk) 1 9 7 2 (nom. nud.) epimastopora piae .homann, pl. 4, fig. 29.untere ringmauer, rattendorfer alpe, friuli venezia giulia (italie): sakmarien (rattendorfer schichten, unterer pseudoschwagerinenkalk); pl. 4, fig. 31.sw zollner see, w rattendorfer alpe, kärnten (autriche): carbonifère, silésien, westphalienstéphanien (höhere auernigschichten) 1 9 7 4 (nom. nud.) epimastopora piae .chuvashov, pl. ix, fig. 2-6.nw yekaterinburg, w oural (fédération de russie): assélien 1979a (?) (nom. nud.) cf. globuliferoporella ? piae [sic].roux, pl. 20, fig. 8.w blind fiord, ellesmere, nunavut (canada): sakmarien (fm belcher channel) 1 9 8 0 (nom. nud.) epimastopora piae .e. flügel, pl. 6, fig. 3.treßdorfer alm, kärnten (autriche): permien inférieur (treßdorfer kalk); pl. 6, fig. 4.forni avoltri, friuli venezia giulia (italie): permien inférieur (trogkofelkalk) 1 9 8 0 (nom. nud.) epimastopora piae .e. flügel & flügel-kahler, pl. 6, fig. 3 pars & 8.ne col mezzodì, forni avoltri, friuli venezia giulia (italie): permien inférieur (trogkofelkalk) 1982 (nom. nud.) epimastopora piae .mu, pl. v, fig. 2-3.xizang / tibet (chine populaire): carbonifère, silésien 1 9 8 4 (nom. nud.) epimastopora piae .e. flügel, kochansky-devidé & ramovπ, pl. 30, fig. 5-6.straæa, bled (slovénie): permien “moyen” 1 9 8 6 (?) (nom. nud.) epimastopora ? p i a e .mirkoviê, pl. iii, fig. 3.3.kuta, nikπiêka æupa, monténégro (yougoslavie): permien “moyen” (trogkofelkalk) 1987 (?) (nom. nud.) cf. “epimastopora piae” .mamet et al., pl. 20, fig. 8.extrait de roux (1979a: pl. 20, fig. 8) 1 9 8 9 (nom. nud.) epimastopora piae .vachard, pl. 6, fig. 4 & 6-9.pulau apat, jambi province, sumatra (indonésie): assélien moyen-sakmarien (assélien supérieur probable) 1991 (nom. nud.) epimastopora piae .e. flügel et al., pl. 47, fig. 6.pietra di salomone, sw palazzo adriano, sw prizzi, sicile (italie): permien *epimastopora piai kordé 1951 1951 epimastopora piai n. gen. n. sp.kordé, pl. i, fig. 1-3.n oural (fédération de russie): carbonifère, s i l é s i e n.“holotype” (syntypes): pl. i, fig. 1-3, lame mince n° ? 923, collection k.b. kordé, moscou (fédération de russie) 1963 epimastopora piai .maslov in bakhrameeba et al., pl. xvii, fig. 6.(fédération de russie): carbonifère 1966 gyroporella symetrica .e. flügel, pl. 7, fig. 1-2.kärnten (autriche): permien inférieur (oberer pseudoschwagerinenkalk) 1970a epimastopora piai .kochansky-devidé, pl. xxiii, fig. 10.w karavanke (slovénie): permien inférieur (trogkofelkalk) 58 geologia croatica 53/1 epimastopora regularis johnson 1951, non 1946 [cf. paraepimastopora regularis (johnson 1951) roux 1979 ] epimastopora rolloensis rácz 1964, nom. nud. [cf. epimastoporella rolloensis (rácz 1964) roux 1979, nom. nud. ] epimastopora seleukensis kulik 1978 1978 epimastopora seleukensis n. sp.kulik, pl. v, fig. 7-8.shakhtau massif, bashkirskaya (fédération de russie): assélien, kurmainskien (zone à schwagerina sphaerica et pseudofusulina firma, zone ass3). holotype: pl. v, fig. 7, lame mince n° 4513/45a, collection e.l. kulik, geologicheski institut akademije nauk sssr (fédération de russie) 1980 epimastopora seleukensis .e. flügel & flügel-kahler, pl. 6, fig. 3 pars.ne col mezzodì, forni avoltri, friuli venezia giulia (italie): permien inférieur (trogkofelkalk) epimastopora ? sphaenopora chuvashov 1974 [cf. sphenoporella sphenopora (chuvashov 1974) in chuvashov et anfimov 1988 ] epimastopora symetrica (johnson 1951) roux 1979 [= globuliferoporella symetrica (johnson 1951) chuvashov 1974; = gyroporella symetrica johnson 1951 ] 1951 gyroporella symetrica n. sp.johnson, pl. 8, fig. 7; pl. 10, fig. 1-5.apache mts, texas (états-unis d’amérique): guadalupien (probablement ? capitanien).types: lames minces n° 1108 & 1117 (? pl. 8, fig. 7 et/ou pl. 10, fig. 1-5), collection h.j. johnson, colorado school of mines, golden, colorado (états-unis d’amérique) 1963 gyroporella symetrica .johnson, pl. 58, fig. 1-2, extrait de johnson (1951: pl. 10, fig. 4-5); pl. 58, fig. 35, extrait de johnson (1951: pl. 10, fig. 1-3) 1964 gyroporella symetrica .glintzboeckel & rabaté, pl. lxxix, fig. 1 pars.djebel tebaga (tunisie): permien “supérieur” 1966 non gyroporella symetrica [= epimastopora piai ].e. flügel, pl. 7, fig. 1-2 1972 gyroporella symetrica .homann, pl. 6, fig. 43.untere ringmauer, rattendorfer alpe, friuli venezia giulia (italie): sakmarien (rattendorfer schichten, unterer pseudoschwagerinenkalk) 1974 globuliferoporella symetrica n. gen. n. comb.chuvashov, pl. xii, fig. 1.d’après chuvashov et al. (1993): chusovaya river, nw yekaterinburg, w oural (fédération de russie): assélien; pl. xii, fig. 27.w yekaterinburg, w oural (fédération de russie): assélien 1977 gyroporella symmetrica [sic].e. flügel, pl. 3/3 pars.treßdorfer alm, kärnten (autriche): sakmarienartinskien (treßdorfer kalk) 1978 globuliferoporella symetrica .kulik, pl. vii, fig. 3.shakhtau massif, bashkirskaya (fédération de russie): sakmarien, sterlitimakien (zone à pseudofusulina callosa , sous-zone st1); pl. vii, fig. 4.shakhtau massif, bashkirskaya (fédération de russie): sakmarien, sterlitimakien (zone à p s e u d o f u s u l i na urdalensis , sous-zone st2); pl. vii, fig. 5.shakhtau massif, bashkirskaya (fédération de russie): sakmarien; pl. vii, fig. 6.shakhtau massif, bashkirskaya (fédération de russie): sakmarien, tastubien (zone à pseudofusulina moelleri, sous-zone ts2) 1979a globuliferoporella symetrica .roux, pl. 17, fig. 8.péninsule de grinnel, devon, nunavut (canada): sakmarien (fm belcher channel); pl. 17, fig. 9-11.fish creek, yukon territory (canada): permien “inférieur” (fm cache creek) 1979b epimastopora symetrica n. comb.roux, p. 807, non figurée 1979 epimastopora symetrica .mamet et al., pl. 3, fig. 8.otto fiord, ellesmere, nunavut (canada): carbonifère, silésien (fm nansen) 1979 globuliferoporella symetrica .zagorodnjuk, pl. i, fig. 7.voskresenskoye, bashkirskaya (fédération de russie): carbonifère, silésien, gzhélien (c3c); pl. ii, fig. 1.voskresenskoye, bashkirskaya (fédération de russie): carbonifère, kasimovien (c3b) 1980 globuliferoporella symetrica .e. flügel, pl. 9, fig. 1.forni avoltri, friuli venezia giulia (italie): permien inférieur (trogkofelkalk) 59granier & grgasoviê: les algues dasycladales du permien et du trias... 1980 globuliferoporella symetrica .e. flügel & flügel-kahler, pl. 7, fig. 1-3.ne col mezzodì, forni avoltri, friuli venezia giulia (italie): permien inférieur (trogkofelkalk) 1986 globuliferoporella symmetrica [s i c].milanoviê, pl. iii, fig. 9.gorski kotar (croatie): permien “inférieur”-”moyen” 1986 globuliferoporella symetrica globuliferoporella simetrica [sic] globuliferopoporella simetrica [sic].mirkoviê, pl. i, fig. 2.1.vasiljeviêi, nikπiêka æupa, monténégro (yougoslavie): permien “moyen” (trogkofelkalk); pl. vi, fig. 1.2; pl. vii, fig. 4.gorica, nikπiêka æupa, monténégro (yougoslavie): permien (trogkofelkalk bellerophon limestone) 1986 (?) globuliferoporella cf. s y m e t r i c a.mirkoviê, pl. iii, fig. 3.3.kuta, nikπiêka æupa, monténégro (yougoslavie): permien “moyen” (trogkofelkalk) 1987 epimastopora symetrica .mamet et al., pl. 17, fig. 8-11, extrait de roux (1979a: pl. 17, fig. 8-11) 1988 globuliferoporella symetrica .chuvashov & anfimov, pl. xxvi, fig. 5-6.sw oural (fédération de russie): carbonifère, silésien, gzhélien 1988 globuliferoporella symetrica e. flügel & kraus, pl. 3, fig. 4 pars.e san cándido / innichen, valle di sesto / sextental, trentino alto adige (italie): permien inférieur (sexten breccia) 1990 globuliferoporella symetrica .e. flügel, pl. 2, fig. 2.kapiskaya, ne kinik, sse balya (turquie): murghabien (zone à neoschwagerina / partie moyenne) 1991 epimastopora symetrica .mamet, pl. iii, fig. n-o.little fish (cache) creek, yukon territory (canada): assélien 1993 globuliferoporella symetrica .chuvashov et al., pl. 14, fig. 8, extrait de chuvashov (1974: pl. xii, fig. 1 pars); pl. 14, fig. 9.chusovaya river, nw yekaterinburg (fédération de russie): assélien 1996 epimastopora symetrica .mamet, pl. 1, fig. 13-14.colquencha, s la paz (bolivie): permien inférieur (groupe de copacabana, zone à eoparafusulina ) epimastopora yoshimurai konishi 1953 1953 epimastopora yoshimurai n. sp.konishi, pl. 11, fig. 16-18 & 19.c.pai, bandon., mayphongson (thaïlande): permien “inférieur”.“cotypes” (syntypes): pl. 11, fig.16-18 & 19.c, pp7202, lames minces n° 123k 6-7 & 124kb 3, geological institute, university of tokyo (japon) epimastopora elliott 1956, nom. nud. [illégitime car c’est un homonyme postérieur de epimastopora pia ex kordé 1951, emend. roux 1979 ] epimastopora alpha elliott 1956, nom. nud. [rejetée en accord avec l’article 23.6 du c.i.n.b. ] 1906 ? gyroporella .gortani, pl. i, fig. 1.forni avoltri, friuli venezia giulia (italie): permo-carbonifère 1 9 5 6 (nom. nud.) epimastopora alpha n. sp.elliott, p. 327, non figurée.holotype (non figuré): pl. i, fig. 1 in gortani (1906) *epimastopora beta elliott 1956, nom. nud. [rejetée en accord avec l’article 23.6 du c.i.n.b.; “synonyme” de epimastoporella japonica (endo 1951) roux 1979 ] epimastoporella roux 1979 epimastoporella alpina kochansky et herak ex roux 1979 [= epimastopora alpina kochansky et herak 1960, nom. nud. ] 1937 (nom. nud.) epimastopora n. sp.pia, pl. 13(97), fig. 4.col mezzodì, forni avoltri, friuli venezia giulia (italie): permien inférieur (trogkofelkalk) 1946 (nom. nud.) epimastopora sp.johnson, pl. 1, fig. 1, extrait de pia (1937: pl. 13(97), fig. 4) 1960 (nom. nud.) epimastopora alpina n. sp.kochansky & herak, pl. iv, fig. 1-4.jezersko, n feuëa (slovénie): 60 geologia croatica 53/1 léonardien (trogkofelkalk).holotype (non figuré): pl. 13(97), fig. 4 in pia (1937), recélant plusieurs spécimens, lame mince n° 126b, collection j. von pia, naturhistorisches museum, wien (autriche) 1 9 6 4 a (nom. nud.) epimastopora alpina .kochansky-devidé, pl. ii, fig. 5 pars.mliniπte, oπljak, radina kosica & raduë, sv. rok, lika (croatie): permien inférieur (base rattendorfer schichten) 1965 (?) (nom. nud.) epimastopora alpina .kordé, pl. lv, fig. 1-2.ogbin 2 (arménie): guadalupien 1965 (nom. nud.) epimastopora alpina .ramovπ & kochansky-devidé, pl. ix, fig. 8.ortnek (slovénie): permien 1 9 6 6 (nom. nud.) epimastopora alpina .e. flügel, pl. 6, fig. 4-5.kärnten (autriche): permien inférieur (oberer pseudoschwagerinenkalk) 1970a (nom. nud.) epimastopora alpina .kochansky-devidé, pl. xxiii, fig. 7-8 & 11.w karavanke (slovénie): permien “inférieur” 1 9 7 2 (nom. nud.) epimastopora alpina .homann, pl. 4, fig. 25.se schulterkofel, rattendorfer alpe, kärnten (autriche): sakmarien (rattendorfer schichten, unterer pseudoschwagerinenkalk); pl. 5, fig. 39.e treßdorfer höhe, kärnten (autriche): sakmarien (rattendorfer schichten, unterer pseudoschwagerinenkalk) 1 9 7 4 (?) (nom. nud.) epimastopora cf. a l p i n a .mirkoviê, pl. vii, fig. 2.luæac, ivangrad, e monténégro (yougoslavie): sakmarien 1 9 7 4 (nom. nud.) epimastopora alpina .mirkoviê, pl. vi, fig. 1.lacina voda, mujiêa reëina, e monténégro (yougoslavie): sakmarien; pl. viii, fig. 3 pars.izlasci, e monténégro (yougoslavie): sakmarien 1 9 7 7 (nom. nud.) epimastopora alpina .e. flügel, pl. 3/2 pars.eustachiushütte, trögern, kärnten (autriche): assélien (oberer pseudoschwagerinenkalk) 1 9 7 8 (nom. nud.) epimastopora alpina .anelkoviê, pl. xxxix, fig. 5-6, extrait de kochansky-devidé (1970a: pl. xxiii, fig. 7-8); pl. xl, fig. 10, extrait de kochansky & herak (1960: pl. iv, fig. 2) 1 9 7 8 (nom. nud.) epimastopora alpina .kulik, pl. v, fig. 1.shakhtau massif, bashkirskaya (fédération de russie): assélien, kurmainskien (zone à schwagerina moelleri et pseudofusulina fecunda, zone ass2); pl. v, fig. 2.shakhtau massif, bashkirskaya (fédération de russie): assélien, kurmainskien (zone à schwagerina sphaerica et pseudofusulina firma , zone ass3); pl. v, fig. 3.shakhtau massif, bashkirskaya (fédération de russie): sakmarien, tastubien (zone à pseudofusulina moelleri, sous-zone ts1) 1 9 7 8 (nom. nud.) epimastopora alpina .lys et al., pl. 5, fig. 2.a.saïd kalateh viru, ne téhéran, e elbourz (iran): assélien inférieur 1979 (nom. nud.) epimastopora alpina .e. flügel, pl. 1, fig. 6 pars.forni avoltri, friuli venezia giulia (italie): sakmarien (trogkofelkalk) 1979b epimastoporella alpina n. comb.roux, p. 809, non figurée.typification et validation de l’espèce; lectotype (non figuré): pl. 13(97), fig. 4, “thalle du centre gauche” in pia (1937), lame mince n° 126b, collection j. von pia, naturhistorisches museum, wien (autriche) 1980 epimastopora alpina .e. flügel & flügel-kahler, pl. 5, fig. 1-7; pl. 7, fig. 9.ne col mezzodì, forni avoltri, friuli venezia giulia (italie): permien inférieur (trogkofelkalk) 1980 epimastopora alpina .e. flügel, pl. 6, fig. 1.rio valp, forni avoltri, friuli venezia giulia (italie): permien inférieur (brekzie); pl. 6, fig. 2; pl. 8, fig. 3.forni avoltri, friuli venezia giulia (italie): permien inférieur (trogkofelkalk); pl. 10, fig. 5.forni avoltri, friuli venezia giulia (italie): permien inférieur 1980 “epimastopora” alpina .vachard, pl. 23, fig. 1 pars; pl. 25, fig. 1 pars.khwahan, tezak (afghanistan): artinskien supérieur 1980 “e p i m a s t o p o r a ” ex gr. alpina .vachard, pl. 7, fig. 7.e.khwahan, tezak (afghanistan): artinskien supérieur 1982 epimastopora alpina .mu, pl. v, fig. 10.xizang / tibet (chine populaire): carbonifère, silésien 1986 epimastopora alpina .mirkoviê, pl. vi, fig. 1 pars.gorica, nikπiêka æupa, monténégro (yougoslavie): permien (trogkofelkalk bellerophon limestone) 1986 (?) epimostopora c f . a l p i n a [s i c].mirkoviê, pl. vi, fig. 4 pars.gorica, nikπiêka æupa, monténégro (yougoslavie): permien (trogkofelkalk bellerophon limestone) 1988 epimastopora alpina .e. flügel & kraus, pl. 2, fig. 7.e san cándido / innichen, valle di sesto / sextental, trentino alto adige (italie): permien inférieur (sexten breccia) 1 9 8 8 b (nom. nud.) pseudoepimastopora alpina [s i c].lys, pl. x, fig. 2.a-b, extrait de lys et al. (1978: pl. 5, fig. 2.a-b) 61granier & grgasoviê: les algues dasycladales du permien et du trias... 1997 epimastoporella alpina .sremac & aljinoviê, pl. ii, fig. 5 pars.kriæ potok, mrzla vodica, gorski kotar (croatie): assélien; pl. iii, fig. 5.kosmaëev brijeg, mrzla vodica, gorski kotar (croatie): assélien epimastoporella ? ampullacea elliott ex roux 1979 [= pseudoepimastopora ampullacea elliott 1968, nom. nud. ] 1968a (nom. nud.) pseudoepimastopora ampullacea n. sp.elliott, pl. 18, fig. 1-2 & 5-7.ora, mosul liwa, n irak (irak): permien (zinnar fm).holotype: pl. 18, fig. 1, lame mince n° v52089; paratype(s): pl. 18, fig. 2, lame mince n° v52090 (et pl. 18, fig. 7, lame mince n° v52094), british museum (natural histo ry), london (royaume-uni) 1979b epimastoporella ? ampullacea n. comb.roux, p. 809, non figurée.validation de l’espèce 1 9 9 1 (?) (nom. nud.) pseudoepimastopora cf. a m p u l l a c e a .e. flügel et al., pl. 47, fig. 5.w pietra di salomone, sw palazzo adriano, sw prizzi, sicile (italie): permien epimastoporella hunzaensis (zanin buri 1965) roux 1979 [= epimastopora hunzaensis zanin buri 1965 ] 1965b epimastopora hunzaensis n. sp.zanin-buri, pl. 8, fig. 1-6; pl. 9, fig. 1-6.chapursan valley, w karakorum (pakistan): permien inférieur-moyen, karachiatirien-darvasien.holotype: pl. 8, fig. 6, lame mince n° m 46/4, coll. n° 1447, collection c. zanin buri, laboratorio di micropaleontologia, istituto di paleontologia, università di milano (italie) 1966 epimastopora hunzaensis .e. flügel, pl. 6, fig. 2.kärnten (autriche): permien inférieur (oberer pseudoschwagerinenkalk) 1972 epimastopora hunzaensis .homann, pl. 4, fig. 32.untere ringmauer, rattendorfer alpe, friuli venezia giulia (italie): sakmarien (rattendorfer schichten, unterer pseudoschwagerinenkalk) 1979a epimastopora hunzaensis .roux, pl. 15, fig. 13.girty creek, ellesmere, nunavut (canada): carbonifère, silésien, moscovien moyen ou plus jeune (fm nansen); pl. 15, fig. 14.n otto fiord, ellesmere, nunavut (canada): carbonifère, silésien, moscovien moyen (fm nansen) 1979b epimastoporella hunzaensis n. comb.roux, p. 809, non figurée 1980 epimastopora hunzaensis .e. flügel & flügel-kahler, pl. 6, fig. 4.ne col mezzodì, forni avoltri, friuli venezia giulia (italie): permien inférieur (kalkbrekzie) 1982 epimastopora hunzaensis .mu, pl. v, fig. 8-9.xizang / tibet (chine populaire): carbonifère / silésien permien “inférieur” / partie supérieure 1987 epimastoporella hunzaensis .mamet et al., pl. 15, fig. 13-14, extrait de roux (1979a: pl. 15, fig. 13-14) epimastoporella iwaizakiensis (endo 1953) roux 1979 [= epimastopora iwaizakiensis endo 1953] 1953a epimastopora iwaizakiensis n. sp.endo, pl. xi, fig. 7-9.iwaizaki, motoyoshi-gun, kitakami mts, honshū (japon): permien “supérieur”.syntypes: pl. xi, fig. 7-9, lames minces n° 129 & 133, n° 10845 & 10850, department of earth sciences, saitama university, urawa (japon) 1 9 6 3 (nom. nud.) pseudoepimastopora iwaizakiensis n. comb.h. flügel, pl. 1, fig. 6.aladag / bademli, ne alanya (turquie): permien 1 9 7 2 (?) (nom. nud.) pseudoepimastopora iwaizakiensis .homann, pl. 5, fig. 36.w zweikofel, kärnten (autriche): sakmarien (rattendorfer schichten, oberer pseudoschwagerinenkalk) 1979 epimastoporella iwaizakiensis.mamet et al., pl. 3, fig. 4-5.otto fiord, ellesmere, nunavut (canada): carbonifère, silésien (fm nansen) 1979a epimastopora iwaizakiensis.roux, pl. 16, fig. 4-9, 11 & 13.blind fiord, ellesmere, nunavut (canada): assélien supérieur (fm belcher channel); pl. 16, fig. 10 & 12.n otto fiord, ellesmere, nunavut (canada): carbonifère, silésien (fm nansen) 1979b epimastoporella iwaizakiensis n. comb.roux, p. 809, non figurée 1982 (nom. nud.) pseudoepimastopora iwaizakiensis .mu, pl. vi, fig. 3-4.xizang / tibet (chine populaire): carbonifère, silésien 1 9 8 4 (nom. nud.) pseudoepimastopora iwaizakiensis .e. flügel, kochansky-devidé & ramovπ, pl. 30, fig. 4.straæa, bled (slovénie): permien “moyen” 62 geologia croatica 53/1 1987 epimastoporella iwaizakiensis.mamet et al., pl. 16, fig. 4-13, extrait de roux (1979a: pl. 16, fig. 4-13) 1 9 9 1 (nom. nud.) pseudoepimastopora iwaizakiensis .e. flügel et al., pl. 47, fig. 7.w pietra di salomone, sw palazzo adriano, sw prizzi, sicile (italie): permien *epimastoporella japonica (endo 1951) roux 1979 [= epimastopora japonica endo 1951] 1906 ? gyroporella .gortani, pl. i, fig. 2.forni avoltri, friuli venezia giulia (italie): permo-carbonifère 1951 epimastopora japonica n. sp.endo, pl. 11, fig. 1-2.sakamotozawa, hikoroichi-mura, kesen-gun, iwate-ken, honshū (japon): permien “inférieur”.“cotypes” (syntypes): pl. 11, fig. 1-2, lames minces n° 14 & 81, specimen (?) n° 10763, laboratory (department) of earth sciences, saitama universi ty, urawa (japon) 1953b (?) epimastopora cf. japonica .endo, pl. ix, fig. 1-4.mujinazawa valley, chichibu-gun, niigata-ken, honshū (japon): carbonifère, silésien 1956 (nom. nud.) epimastopora beta n. gen. n. sp.elliott, p. 327, non figurée.holotype (non figuré): pl. i, fig. 2 in gortani (1906) 1959 epimastopora japonica .endo, pl. 38, fig. 16-18.hatahoko, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien (gonbō fm, zone à parafusulina = zone à pseudoschwagerina [sic]) 1 9 6 0 (nom. nud.) pseudoepimastopora japonica n. comb.endo, pl. 44, fig. 1.n kobayaski, isa, s mine-shi, yamaguchi-ken, honshū (japon): permien inférieur (akiyoshi limestone group, sous-zone à p s e u d o fusulina vulgaris) 1960 epimastopora likana n. sp.kochansky & herak, pl. iv, fig. 5 & 9-10.staniπte, mali kraj, velebit mt (croatie): permien inférieur (rattendorfer schichten); pl. iv, fig. 6.?; pl. iv, fig. 7.robijaëa, mali kraj, velebit mt (croatie): permien inférieur (rattendorfer schichten); pl. iv, fig. 8.alanac, velebit mt (croatie): permien inférieur (rattendorfer schichten).holotype: pl. iv, fig. 5, lame mince n° 1731, collection v. kochansky-devidé & m. herak, geoloπko-paleontoloπki zavod, prirodoslovnomatematiëki fakultet [geological and palaeontological institute, faculty of sciences ], zagreb (croatie) 1960 e p i m a s t o p o r a sp.kochansky & herak, pl. iv, fig. 11.bruπane, velebit mt (croatie): carbonifère, ouralien 1962 epimastopora likana .kochansky-devidé & milanoviê, pl. vi, fig. 3.sjerogoπte, rivière tara, monténégro (yougoslavie): sakmarien supérieur ou artinskien inférieur 1963 epimastopora likana .herak, fig. 31, extrait de kochansky & herak (1960: pl. iv, fig. 5) 1 9 6 3 (nom. nud.) pseudoepimastopora likana n. comb.h. flügel, pl. 1, fig. 5.dizdere, djulfa, azerbaïdjan iranien (iran): permien 1963 (nom. nud.) pseudoepimastopora japonica .johnson, pl. 69, fig. 1, extrait de endo (1960: pl. 44, fig. 1) 1965 (?) epimastopora cf. likana.ramovπ & kochansky-devidé, pl. ix, fig. 7.ortnek (slovénie): permien 1 9 6 6 (nom. nud.) pseudoepimastopora likana .e. flügel, pl. 7, fig. 3-4.kärnten (autriche): permien inférieur (oberer pseudoschwagerinenkalk) 1968a (?) (nom. nud.) pseudoepimastopora cf. likana.elliott, pl. 18, fig. 3-4.djebel qamar (oman): permien 1 9 6 8 a (nom. nud.) pseudoepimastopora japonica .endo, pl. xxxiv, fig. 3-9.e barrio manaul, mansalay, e mindoro (philippines): permien dans un conglomérat jurassique (?) 1969 (nom. nud.) pseudoepimastopora japonica .endo, pl. xli, fig. 5-7.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancel lina) 1970a epimastopora likana .kochansky-devidé, pl. xxiii, fig. 9.w karavanke (slovénie): permien “inférieur” 1 9 7 1 (nom. nud.) pseudoepimastopora japonica .ishijima et al., pl. 15, fig. 4.sakaishimachibun, agano-mura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur” 1972 (nom. nud.) pseudoepimastopora japonica .homann, pl. 5, fig. 34.nw zottach-kogel, kärnten (autriche): sakmarien (rattendorfer schichten, oberer pseudoschwagerinenkalk) 1 9 7 2 (nom. nud.) pseudoepimastopora kroatiaca n. sp.homann, pl. 5, fig. 35 & 38.w zweikofel, kärnten (autriche): sakmarien (rattendorfer schichten, oberer pseudoschwagerinenkalk).holotype: pl. iv, fig. 11 in kochansky & herak (1960), lame mince n° 387, collection v. kochansky-devidé & m. he63granier & grgasoviê: les algues dasycladales du permien et du trias... rak, geoloπko-paleontoloπki zavod, prirodoslovno-matematiëki fakultet [geological and palaeonto logical institute, faculty of sciences ], zagreb (croatie) 1 9 7 2 (nom. nud.) pseudoepimastopora likana .homann, pl. 4, fig. 33.w zweikofel, kärnten (autriche): sakmarien (rattendorfer schichten, oberer pseudoschwagerinenkalk); pl. 5, fig. 37.untere ringmauer, rattendorfer alpe, friuli venezia giulia (italie): sakmarien (rattendorfer schichten, unterer pseudoschwagerinenkalk) 1 9 7 4 (nom. nud.) pseudoepimastopora likana .chuvashov, pl. xi, fig. 1-8.w yekaterinburg, w oural (fédération de russie): assélien 1978 epimastopora likana .anelkoviê, pl. xxxix, fig. 8, extrait de kochansky-devidé (1970a: pl. xxiii, fig. 9); pl. xl, fig. 9, extrait de kochansky & herak (1960: pl. iv, fig. 10) 1978 (nom. nud.) pseudoepimastopora likana .kulik, pl. vi, fig. 1-3.shakhtau massif, bashkirskaya (fédération de russie): sakmarien, sterlitimakien (zone à pseudofusulina urdalensis , sous-zone st2); pl. vi, fig. 4.shakhtau massif, bashkirskaya (fédération de russie): sakmarien, tastubien (zone à p s e u d o f u s u l i n a moelleri, sous-zone ts1) 1 9 7 8 (nom. nud.) pseudoepimastopora likana .lys et al., pl. 5, fig. 2.a-b.viru, ne téhéran, e elbourz (iran): assélien / partie inférieure 1 9 7 9 (nom. nud.) pseudoepimastopora likana .ramovπ & kochansky-devidé, pl. 1, fig. 3 pars.n julijske alpe (slovénie): carbonifère, silésien, gzhélien (oberer auernigschichten) 1979a epimastopora japonica .roux, pl. 15, fig. 6 & 12.blind fiord, ellesmere, nunavut (canada): sakmarien (fm belcher channel); pl. 15, fig. 7.n otto fiord, ellesmere, nunavut (canada): assélien ou sakmarien (fm nansen); pl. 15, fig. 8-9; pl. 16, fig. 1.n otto fiord, ellesmere, nunavut (canada): sakmarien (fm nansen); pl. 15, fig. 10.blind fiord, ellesmere, nunavut (canada): permien (fm belcher fig. 12 epimastopora likana (kochansky & herak, 1960, pl. iv, fig. 7), x44. fig. 13 epimastopora likana (kochansky & herak, 1960, pl. iv, fig. 5), x22. 64 geologia croatica 53/1 channel); pl. 15, fig. 8-9; pl. 16, fig. 3.n otto fiord, ellesmere, nunavut (canada): carbonifère, silésien (fm nansen); pl. 16, fig. 2.mt bayley, ellesmere, nunavut (canada): sakmarien (fm antoinette) 1979b epimastoporella japonica n. gen. n. comb.roux, p. 809, non figurée.typification de l’espèce; “holo type” (lectotype): pl. 11, fig. 2 in endo (1951) 1979b epimastoporella kroatiaca n. comb.roux, p. 809, non figurée 1979b epimastoporella likana n. comb.roux, p. 809, non figurée 1979 (nom. nud.) pseudoepimastopora likana .zagorodnjuk, pl. i, fig. 5.voskresenskoye, bashkirskaya (fédération de russie): carbonifère, silésien, kasimovien (c3b) 1980 e p i m a s t o p o r a ? l i k a n a.e. flügel & flügel-kahler, pl. 6, fig. 6 pars; pl. 7, fig. 4-6 & 8.ne col mezzodì, forni avoltri, friuli venezia giulia (italie): permien inférieur (trogkofelkalk) 1980 “e p i m a s t o p o r a ” l i k a n a .vachard, pl. 23, fig. 3 & 9.khwahan, tezak (afghanistan): artinskien supérieur 1 9 8 1 (nom. nud.) pseudoepimastopora nipponica [s i c].nakamura, pl. 1, fig. 6.ishiyama, o _ n o c hō tanigumimura, gifu-ken, honshū (japon): permien (ishiyama limestone) 1981 “e p i m a s t o p o r a ” l i k a n a .vachard in vachard & montenat, pl. 3, fig. 6.khwaja bahadur, tezak (afghanistan): artinskien 1981 (?) “e p i m a s t o p o r a ” cf. l i k a n a .vachard in vachard & montenat, pl. 3, fig. 4.mansur, tezak (afghanistan): artinskien 1987 epimastoporella japonica .mamet & roux in mamet et al., pl. 15, fig. 6-12, extrait de roux (1979a: pl. 15, fig. 6-12); pl. 16, fig. 1-3, extrait de roux (1979a: pl. 16, fig. 1-3) 1988 epimastopora .deloffre, pl. 3, fig. 13, extrait de kochansky & herak (1960: pl. iv, fig. 7) 1990 (nom. nud.) pseudoepimastopora likana .e. flügel, pl. 2, fig. 1.e balya, wnw balikesir (turquie): bolorien (zone à misellina) 1991 (?) e p i m a s t o p o r e l l a .riding & guo, fig. 8.trogkofel / creta di aip, friuli venezia giulia (italie): permien inférieur (oberer pseudoschwagerinenkalk) 1993 (nom. nud.) pseudoepimastopora likana .chuvashov et al., pl. 14, fig. 10-11.forage urtatau-sarybulak-2, s pré-oural (fédération de russie): assélien 1996 epimastoporella japonica .mamet, pl. 1, fig. 9-10.colquencha, s la paz (bolivie): permien (groupe de copacabana, zone à eoparafusulina ) 1997 epimastopora kroatiaca [sic].sremac & aljinoviê, pl. iii, fig. 4 pars.kosmaëev brijeg, mrzla vodica, gorski kotar (croatie): assélien 1997 (nom. nud.) pseudoepimastopora likana .vachard & fourcade, fig. 12.15.suquinay, purulhà, baja verapaz (guatemala): bolorien (fm chócal, chócal de suquinay) epimastoporella ketini (bilgütay 1960) roux 1979, nom. nud. [= epimastopora ketini bilgütay 1960, nom. nud. ] 1 9 6 0 (nom. nud.) epimastopora ketini n. sp.bilgütay, pl. ii, fig. 5; pl. iii, fig. 1-3.hasanoǧlan, e ankara (turquie): permien “inférieur”.types: pl. ii, fig. 5; pl. iii, fig. 2, lame mince coll. n° 18/7; pl. iii, fig. 3, lame mince coll. n° 19; pl. iii, fig. 1, lame mince coll. n° ?, collection u. bilgütay, mineral research and exploration institute of turkey (m.t.a.), ankara (turquie) 1 9 6 5 (nom. nud.) epimastopora ketini.güvenç, pl. m8, fig. 1 pars.yatan tepe, w taurus (turquie): permien “supérieur” 1 9 7 2 (nom. nud.) epimastopora ketini.homann, pl. 4, fig. 30.rattendorfer sattel, n treßdorfer höhe, kärnten (autriche): sakmarien (rattendorfer schichten, grenzland fm) 1 9 7 2 (nom. nud.) (?) epimastopora c f . e. ketini.homann, pl. 6, fig. 48.untere ringmauer, rattendorfer alpe, friuli venezia giulia (italie): sakmarien (rattendorfer schichten, unterer pseudoschwagerinenkalk) 1979b (nom.nud.) epimastoporella ketini n. comb.roux, p. 809, non figurée epimastoporella kosakiensis (konishi 1954) roux 1979 [= epimastopora kosakiensis konishi 1954 ] 1954a epimastopora kosakiensis n. sp.konishi, pl. ii, fig. 23-25.kosaki, shimomatsukoma-mura, yatsushiro-gun, kumamota-ken, kyūs hū (japon): permien moyen (kosaki fm, zone à n e o s c h w a g e r i n a-v e r 65granier & grgasoviê: les algues dasycladales du permien et du trias... beeckina).types: pl. ii, fig. 23-25, lames minces n° pp 7244 (k3-1), pp 7245 (k3-3), pp 7245 (k34), pp 7246 (k3-5), pp 7247 (k3-8) et/ou pp 7247 (k3-6), collection k. konishi, ? geological insti tute, university of tokyo (japon) 1979b epimastoporella kosakiensis n. comb.roux, p. 809, non figurée 1984 epimastopora kosakiensis.nakamura & chisaka, pl. 6, fig. 11-12.mt atagoyama, chôshi-shi, chibaken, honshū (japon): permien “supérieur” (takagami conglomerate) epimastoporella kroatiaca homann ex roux 1979 [synonyme postérieur de epimastoporella japonica (endo 1951) roux 1979, d’après mamet et roux in mamet et al. , 1987] epimastoporella likana (kochansky et herak 1960) roux 1979 [synonyme postérieur de epimastoporella japonica (endo 1951) roux 1979, d’après mamet et roux in mamet et al. , 1987] epimastoporella malaysiana (elliott 1968) roux 1979 [= epimastopora malaysiana elliott 1968 ] 1968b epimastopora malaysiana n. sp.elliott, pl. 93, fig. 3-4.kampar, perak (malaisie): permien “moyen”.holotype: pl. 93, fig. 3-4, spécimen v.53442, collection g.f. elliott, british museum (natural his tory), london (royaume-uni) 1979b epimastoporella malaysiana n. comb.roux, p. 809, non figurée epimastoporella pertunda (endo 1960) roux 1979, nom. nud. [cf. pseudoepimastopora pertunda endo 1960, nom. nud. ] epimastoporella rolloensis (rácz 1964) roux 1979, nom. nud. [= epimastopora rolloensis rácz 1964, nom. nud. ] 1 9 6 4 (nom. nud.) epimastopora rolloensis n. sp.rácz, pl. ii, fig. 4-6.wsw siero de la reina, s boca de huérgano, león (espagne): carbonifère, silésien, moscovien inférieur (zone à profusulinella , sous-zone b ).“holotype” (syntypes): pl. ii, fig. 5-6, lame mince n° ii-a-s-16, collection l. rácz, department of stratigraphy and paleontology, leiden university, leiden (pays-bas) 1 9 7 4 (?) (nom. nud.) epimastopora aff. r o l l o e n s i s .chuvashov, pl. ix, fig. 7-10.w yekaterinburg, w oural (fédération de russie): assélien (galet dans un conglomérat sakmarien) 1979b (nom. nud.) epimastoporella rolloensis n. comb.roux, p. 809, non figurée euteutloporella de castro 1993 *euteutloporella triasina (schauroth 1859) de castro 1993 [= neoteutloporella triasina (schauroth 1859) bassoullet et al. 1978; = teutloporella triasina (schauroth 1859) pia 1912 ; = diplopora triasina (schauroth 1859) tornquist 1900 ; = gyroporella triasina (schauroth 1859) gümbel 1872 ; d’abord considérée comme un bryozoaire: chaetetes triasinus schauroth 1859 ] 1855 c h a e t e t e s ?.schauroth, pl. iii, fig. 4.a-l.recoaro terme, w schio, véneto (italie): trias moyen (“niveau von st. cassian”) 1859 chaetetes ? triasinus n. sp.schauroth, p.285, non figurée 1872 gyroporella triasina n. comb.gümbel, pl. d.iii, fig. 12.a-f.recoaro terme, w schio, véneto (italie): trias moyen; pl. d.iii, fig. 13.a-b.mendola, trentino alto adige (italie): trias moyen (mendoladolomit) 1890 gyroporella triasina .schimper & schenk, fig. 30, n° 5, extrait de gümbel (1872: pl. d.iii, fig. 12.a); fig. 30, n° 5.a, extrait de gümbel (1872: pl. d.iii, fig. 12.e); fig. 30, n° 5.b, extrait de gümbel (1872: pl. d.iii, fig. 12.f) 1900 diplopora triasina n. comb.tornquist, pl. iii, fig. 1.a-d.san ulderico, tretto, n schio, véneto (italie): trias moyen (sturia-kalk, trinodosus-niveau) 66 geologia croatica 53/1 1912 teutloporella triasina n. comb.pia, pl. iv(iii), fig. 12-14.san ulderico, tretto, n schio, véneto (italie): trias moyen (monte spitz limestone); pl. iv(iii), fig. 15-16.venedig, san rocco, tretto, n schio, véneto (italie): trias moyen, virglorien; pl. iv(iii), fig. 17.san rocco, tretto, n schio, véneto (italie): trias moyen (fm dei calcari de recoaro) 1912 (?) teutloporella aff. t r i a s i n a .pia, pl. iv(iii), fig. 18-19.w zirkeljoch, n pontebba / pontafel, friuli venezia giulia (italie): trias moyen 1919 (?) teutloporella triasina ?.négris, fig. 72.laurium (grèce): trias 1952a non teutloporella cf. triasina .endo, pl. 12, fig. 3.n sakamotozawa, hikoroichi-mura, kesen-gun, iwateken, honshū (japon): permien “moyen” 1954 teutloporella triasina .lemoine in fallot & solé sabaris, pl. iii; pl. iv, fig. 1-2; pl. v, fig. 2 & 4.cerro de gor, sierra de baza, s gor, granada (espagne): anisien; pl. v, fig. 1.picón de gor, sierra de baza, e gor, granada (espagne): anisien 1961 (?) teutloporella sp. cf. t r i a s i n a .botteron, pl. vii, fig. 3.mont d’or, vaud (suisse): “virglorien” (anisien) supérieur 1961 non teutloporella sp. cf. triasina [= teutloporella peniculiformis].botteron, pl. vii, fig. 4 1965 teutloporella triasina .herak, pl. i, fig. 1-3.brdo, w træië (slovénie): ladinien; pl. i, fig. 4.velika vrπina, sv. rok, lika (croatie): ladinien 1965 (?) teutloporella cf. triasina .herak, pl. ii, fig. 2.debelo brdo, nw knin (croatie): ladinien 1965 (?) teutloporella triasina ?.herak, pl. ii, fig. 3.jelovi vrh, sv. rok, lika (croatie): trias moyen 1969 teutloporella triasina .diaconu & dragastan, pl. i, fig. 1.dealul glimeia, apuseni mts (roumanie): ladinien 1969 non teutloporella triasina [= teutloporella nodosa ].diaconu & dragastan, pl. i, fig. 2 1971 teutloporella triasina .zorn, pl. 17, fig. 3.mte san salvatore, s lugano, ticino (suisse): anisien supérieur ladinien inférieur (mittlerer salvatoredolomit, gervillienhorizont) 1978 neoteutloporella triasina n. comb.bassoullet et al., p. 183, non figurée 1978 teutloporella triasina .bousquet et al., pl. i, fig. 1.ponte dei colombi, lungro acquaformosa, calabria (italie): anisien 1978 teutloporella triasina .ramovπ, fig. 6.4.prisojnik, s kranjska gora (slovénie): trias moyen 1980 diplopora triasina .ramovπ, fig. 7.bistrica, træië (slovénie): ladinien 1985 teutloporella triasina .farabegoli et al., pl. 6.c.rio gelovitz, pietratagliata, pontebba / pontafeldogna, friuli venezia giulia (italie): anisien, illyrien supérieur (arenarie del rio gelovitz) 1993 euteutloporella triasina n. gen. n. comb.de castro, p. 173, non figurée 1998 teutloporella triasina .petek (sokaë), pl. 1, fig. 1-2.carrière hrastenice, polhov gradec, w ljubljana (slovénie): anisien, illyrien supérieur 1998 (?) teutloporella ? triasina .petek (sokaë), pl. 1, fig. 3-4 & 5 pars.carrière hrastenice, polhov gradec, w ljubljana (slovénie): anisien, illyrien supérieur favoporella soka» 1968 [synonyme postérieur de kantia pia 1912, emend. güvenç 1979 ] *favoporella annulata soka» 1968 [synonyme postérieur de diplopora annulatissima pia 1920, d’après ott, 1972c; cf. kantia monregalensis baretti 1919 ] favoporella wu 1991, nom. nud. [illégitime car c’est un homonyme postérieur de favoporella soka» 1968, fondé sur une espèce différente ] *favoporella hexagona wu 1991, nom. nud. 1 9 9 1 a (nom. nud.) favoporella hexagona n. gen. n. sp.wu, pl. ii, fig. 2; pl. iii, fig. 7; pl. iv, fig. 6.xiangbo, longlin county, guangxi (chine populaire): guadalupien, ‘maokouan’.“holotype” (syntypes): pl. ii, 67granier & grgasoviê: les algues dasycladales du permien et du trias... fig. 2; pl. iii, fig. 7; pl. iv, fig. 6, lame mince n° xb 27-8-4, beijing institute of geology, academia sinica, pékin (chine populaire) 1991b (nom. nud.) favoporella hexagona n. gen. n. sp.wu, pl. 20, fig. 2, extrait de wu (1991a: pl. ii, fig. 2); pl. 21, fig. 7, extrait de wu (1991a: pl. iii, fig. 7); pl. 22, fig. 6, extrait de wu (1991a: pl. iv, fig. 6) globuliferoporella chuvashov 1974 [synonyme postérieur de epimastopora pia ex kordé 1951, emend. roux 1979 ] globuliferoporella angulata chuvashov 1974 [cf. epimastopora angulata (chuvashov 1974) roux 1979 ] *globuliferoporella symetrica (johnson 1951) chuvashov 1974 [cf. epimastopora symetrica (johnson 1951) roux 1979 ] goniolinopsis milanovi∆ 1966, emend. mu 1984 *goniolinopsis hexagona milanovi∆ 1966 1966b goniolinopsis hexagona n. gen. n. sp.milanoviê, fig. 3.1-6; pl. i, fig. 1 [= fig. 3.4]; pl. i, fig. 3 & 5; pl. i, fig. 2 [= fig. 3.1]; pl. i, fig. 4 [= fig. 3.4]; pl. i, fig. 6 [= fig. 3.3]; pl. ii, fig. 1-6; pl. ii, fig. 6 [= fig. 3 . 5]; pl. iii, fig. 1 & 3-6; pl. iii, fig. 2 [= fig. 3.6].velebit mt (croatie): artinskien supérieur kazanien inférieur.holotype: fig. 3.1; pl. i, fig. 2 [= fig. 3.1], lame mince n° u-4012/1, collection m. milanoviê, institut za geoloπka istraæivanja [institute of geology ], zagreb (croatie) 1972 (?) goniolinopsis cf. g. hexagona.homann, pl. 6, fig. 51.e treßdorfer höhe, kärnten (autriche): sakmarien (rattendorfer schichten, unterer pseudoschwagerinenkalk) 1978 goniolinopsis hexagona.brönnimann et al. (elliott), pl. 12, fig. 19-22.nwabangyi, southern shan states (birmanie-myanmar): permien “supérieur” (nwabangyi dolomite fm) 1992 goniolinopsis hexagona.vachard et al., pl. iii, fig. 6 pars & 7.n ban na wai, nw thaïlande (thaïlande): murghabien supérieur midien griphoporella pia 1915, emend. barattolo et al. 1991 griphoporella bechstaedti parente et climaco 1999 1999 griphoporella bechstädti n. sp.parente & climaco, pl. 36, fig. 1-12.mte rotonda, e maratea, basilicata (italie): norien .holotype: pl. 36, fig. 1, lame mince n° ac345.4 (d’après le texte) ou ac354.4 (d’après le légende de la figure); isotypes: pl. 36, fig. 2, lame mince n° ac565.1; pl. 36, fig. 3, lame mince n° ac345.15; pl. 36, fig. 4 & 6, lame mince n° ac565.6; pl. 36, fig. 5, 8, 10 & 12, lame mince n° ac345.7; pl. 36, fig. 7, lame mince n° ac565.2; pl. 36, fig. 9, lame mince n° ac560; pl. 36, fig. 11, lame mince n° ac565.5, collection v. zamparelli, dipartimento di scienze della terra, università di napoli “federico ii” (italie) *griphoporella curvata (gümbel 1872) pia 1915 , emend. barattolo et al. 1993 [= gyroporella curvata gümbel 1872 ] 1872 gyroporella curvata n. sp.gümbel, pl. d.iv, fig. 2.a-d.“boca di nota”, probablement passo nota, s bezzecca, val di ledro, n lago di garda, trentino alto adige (italie): “dolomite mit avicula exilis stopp. und megalodon complanatus” et/ou “zahlreichen orten der südalpen”.types: pl. d.iv, fig. 2.a-d, collection c.w. gümbel (coll. prof. pichler), münchen (allemagne) 1908 gyroporella vesiculifera .merciai, pl. vii, fig. 40-43.mte malbe, perugia, umbria (italie): trias supérieur 1915b griphoporella curvata n. comb.pia in spitz & dyrenfurth, pl. i, fig. 11.cucler da jon da d’ontsch, engadin, graubünden (suisse): norien (dolomia principale / hauptdolomit) 68 geologia croatica 53/1 1920 griphoporella curvata .pia, pl. iii, fig. 17 & 19.dasio, n lago di lugano, ticino (suisse): norien (dolomia principale / hauptdolomit); pl. iii, fig. 18.n cucler da jon da d’ontsch, engadin, graubünden (suisse): norien (dolomia principale / hauptdolomit); pl. iii, fig. 20.storo, val d’ámpola, ne lago d’idro, trentino alto adige (italie): norien (dolomia principale / hauptdolomit); pl. iii, fig. 21.inzino, n gardone val trómpia, e lago d’iseo, lombardia (italie): norien 1959 diplopora annulata .“anonyme”, pl. xxiv, bas; pl. xxv; pl. xxvi, haut.mte lovinzola, udine, friuli venezia giulia (italie): norien 1964 griphoporella curvata .sokaë et al., fig. 3.3-4.mali halan, velebit mt (croatie): norien 1965a gryphoporella curvata var. cistiformis n. var. [sic].zanin buri, pl. 62.a-c; pl. 63, fig. 1.a-c.resegone, erve, nw bergamo, lombardia (italie): norien (dolomia principale / hauptdolomit).holotype: pl. 62.a, lame mince n° mb 365 a, coll. n° 1572, collection c. zanin buri, laboratorio di micropale ontologia, istituto di paleontologia, università di milano (italie) 1965a gryphoporella curvata var. c u r v a t a n. var. [s i c].zanin buri, pl. 62 pars; pl. 63, fig. 1 pars & 2-3.resegone, erve, nw bergamo, lombardia (italie): norien (dolomia principale / hauptdolomit) 1965a macroporella retica n. sp.zanin buri, pl. 44-45; pl. 61, fig. 5-6.aviatico, ne bergamo, lombardia (italie): rhétien moyen.holotype: pl. 44.a, lame mince n° mb-s 51, coll. n° 1567, collection don rocco zambelli, laboratorio di micropaleontologia, istituto di paleontologia, università di milano (italie) 1967 (?) griphoporella sp.holzer, pl. 1, fig. 8 pars.s klaus an der pyhrnbahn, steyrtal, oberösterreich (autriche): carnien, cordevolien (wettersteinkalk) 1967 griphoporella curvata .michard, pl. xiv, fig. 2.pradleves-rocca caire, val grana, piemonte (italie): trias supérieur 1967 griphoporella curvata .ott, pl. 13, fig. 4.kohlalpen-tal, kaisergebirge, tirol (autriche): rhétien-lias (en éboulis) 1967 dasycladaceen.wolff, pl. 9, fig. 4.wendelstein, bayern (allemagne): rhétien (bloc dans ‘moränenmaterial’) 1970 griphoporella curvata .patrulius, pl. v, fig. 3-5.piatra şoimului, mt rarǎu, suceava (roumanie): norien 1972 griphoporella curvata .fenninger & holzer, pl. 12, fig. 1.sparber, strobl, salzburg (autriche): trias / lias (dachsteinkalk) 1975 griphoporella curvata .e. flügel, pl. 4, fig. 6.steinplatte, waidring, tirol (autriche): rhétien supérieur 1977 dasycladaceae ind.chiocchini & mancinelli, pl. i, fig. 2; pl. iii, fig. 2.mte carbonaro, nw gaeta, s lazio (italie): rhétien; pl. ii, fig. 1-2; pl. iii, fig. 1.mte cefalo, nw gaeta, s lazio (italie): rhétien 1978 macroporella retica .bassoullet et al., pl. 19, fig. 4, extrait de zanin buri (1965a: pl. 44.a); pl. 19, fig. 5, extrait de zanin buri (1965a: pl. 61, fig. 5) 1978 gryphoporella curvata [sic].bousquet et al., pl. ii, fig. 1.e mte palanuda, piano dell’erba bocca di novaco, s mormanno, calabria (italie): norien terminal; pl. ii, fig. 4 pars.timpone san sagaria, nne morano calabro, calabria (italie): norien terminal; pl. iii, fig. 1.timpone del convento, s campo tenese, e mormanno, calabria (italie): norien; pl. iii, fig. 2 pars.timpone del convento, s campo tenese, e mormanno, calabria (italie): norien terminal 1978 gryphoporella sp. [s i c].bousquet et al., pl. ii, fig. 3.gole del garga, saracena, calabria (italie): ? trias supérieur 1978 gyroporella cf. vesiculifera.carannante et al., fig. 2.e.mti aurunci, s lazio (italie): norien supérieur ? rhétien 1978 dasycladales “tr” [sic].chiocchini & mancinelli, pl. i, fig. 2.mte meta, gran sasso d’italia, abruzzo (italie): norien supérieur 1978 griphoporella curvata .e. flügel, pl. 22, fig. 6.haindlkarbrücke, gesäuse, steiermark (autriche): trias supérieur (dachsteinkalk) 1979 griphoporella curvata .e. flügel, pl. 2, fig. 6.gesäuse, steiermark (autriche): norien supérieur (dachsteinkalk) 1979 griphoporella curvata .senowbari-daryan & schäfer, pl. 1, fig. 7.gruber, feichtenstein, hintersee, salzburg (autriche): trias supérieur 1980a griphoporella curvata .dullo, pl. 2, fig. 3 pars.sw gesäuse, steiermark (autriche): carnien (tisoveckalk) 69granier & grgasoviê: les algues dasycladales du permien et du trias... 1980b griphoporella curvata .dullo, pl. 10, fig. 10; pl. 13, fig. 6.hahnstein, sw gesäuse, steiermark (autriche): trias supérieur (dachsteinkalk) 1980 non griphoporella curvata [= spinaporella andalusica ].martin & delgado, fig. 4 1980 griphoporella curvata .senowbari-daryan, pl. 13, fig. 4.gruber, feichtenstein, hintersee, salzburg (autriche): rhétien supérieur 1981 griphoporella curvata .e. flügel, fig. 10.e.haindlkarbrücke, gesäuse, steiermark (autriche): trias supérieur 1981 griphoporella curvata .piller, fig. 20.steinernes meer, salzburg (autriche): trias supérieur 1981 griphoporella curvata .sadati, pl. 59, fig. 7.hohe wand, niederösterreich (autriche): norien supérieur rhétien inférieur (dachsteinkalk) 1982 griphoporella curvata .e. flügel, pl. 29, fig. 7, extrait de e. flügel (1978: pl. 22, fig. 6) 1982 griphoporella curvata .wurm, pl. 33, fig. 5.gosaukamm, dachsteingruppe, oberösterreich (autriche): norien (dachsteinkalk) 1986 griphoporella curvata .braga, fig. 2.l.sierra de baza, gor baza, granada (espagne): norien (alpujarride complex, santa barbara unit, carbonate fm, member j) 1986 non gyroporella retica [sic, = petrascula iberica ].dragastan & trappe, fig. 5.1.préjano, se logroño, la rioja (espagne): lias, sinémurien inférieur (carniolas fm) 1987 griphoporella curvata .braga & martin, pl. i, fig. 7.sierra de baza, gor baza, granada (espagne): norien 1987 dasycladaceae gen. ind.ciarapica et al., pl. xxvii, fig. 1-6.mte cetona, sw perugia, umbria (italie): rhétien (fm du monte cetona, zone à triasina hantkeni ) 1987 griphoporella curvata .ciarapica et al., pl. xxiv, fig. 1-8; pl. xxv, fig. 3.b & 7.a; pl. xxvi, fig. 2 & 5.mte cetona, sw perugia, umbria (italie): rhétien (fm du monte cetona, zone à triasina hantkeni ) 1987 gyroporella vesiculifera .ciarapica et al., pl. xxiii, fig. 1-10; pl. xxv, fig. 1.a [= pl. xxiii, fig. 5]; pl. xxv, fig. 1.b, 3.a, 4.a, 5.a & 6.a.mte cetona, sw perugia, umbria (italie): rhétien (fm du monte cetona, zone à triasina hantkeni ) 1987 macroporella retica .ciarapica et al., pl. xxii, fig. 1-8; pl. xxv, fig. 2.c & 6.b; pl. xxvi, fig. 1, 3 & 7-8.mte cetona, sw perugia, umbria (italie): rhétien (fm du monte cetona, zone à triasina hantkeni ) 1987 griphoporella curvata .gaetani et al., pl. i (“in basso”) pars.sasso san martino, esino lario, e lago di como, lombardia (italie): norien 1987 gyroporella vesiculifera .gaetani et al., pl. i (“in basso”) pars.sasso san martino, esino lario, e lago di como, lombardia (italie): norien 1987 macroporella retica .gaetani et al., pl. i (“in basso”) pars.sasso san martino, esino lario, e lago di como, lombardia (italie): norien 1987 griphoporella curvata .nicol, pl. 5, fig. 8.schönleitenplateau, hochschwab, steiermark (autriche): norien (aflenz limestone) 1988 griphoporella curvata .deloffre, pl. 3, fig. 11, extrait de pia (1920: pl. iii, fig. 21); pl. 3, fig. 12, extrait de pia (1920: pl. iii, fig. 19) 1988 griphoporella curvata .sartorio & venturini, p. 40-41 = p. 56, centre.erve, nw bergamo, lombardia (italie): norien 1988 dasycladales.sartorio & venturini, p. 219, [= 40-41 = p. 56, centre] 1988 macroporella retica .sartorio & venturini, p. 56, bas.mte lovinzola, udine, friuli venezia giulia (italie): rhétien 1990 griphoporella curvata .de castro, pl. 11, fig. 2; pl. 13, fig. 1.croci d’acerno, n acerno, ene salerno, campania (italie): rhétien 1990 griphoporella curvata .lakew, pl. 49, fig. 3.corni di canzo, nw bergamo, lombardia (italie): rhétien (calcare di zu) 1991 griphoporella curvata .barattolo, pl. iii, fig. 1.erchie, sw vietri sul mare, w salerno, campania (italie): rhétien 1991 griphoporella curvata .barattolo & parente, pl. x.buonabitàcolo, w salerno, campania (italie): rhétien 1991 griphoporella curvata .iannace, fig. 2.13.erchie, sw vietri sul mare, w salerno, campania (italie): norien-rhétien 70 geologia croatica 53/1 1993 griphoporella curvata emend.barattolo et al., pl. 1, fig. 1-10; pl. 3, fig. 2-5; pl. 4, fig. 1-4 & 6; pl. 6.passo nota, s bezzecca, val di ledro, n lago di garda, trentino alto adige (italie): norien; pl. 2, fig. 1-8; pl. 4, fig. 5; pl. 5, fig. 1-4; pl. 7.erchie, sw vietri sul mare, w salerno, campania (italie): norien; pl. 3, fig. 1.vietri sul mare, w salerno, campania (italie): norien.choix d’un néotype: pl. 1, fig. 10, lame mince n° a.8141.17, collection p. de castro, dipartimento di scienze della terra, università di napoli “federico ii” (italie) 1993 griphoporella curvata .senowbari-daryan & e. flügel, pl. 8, fig. 4.gruber, feichtenstein, hintersee, salzburg (autriche): rhétien supérieur 1995 macroporella retica = griphoporella curvata .pugliese, pl. 1, fig. 1-6; pl. 2, fig. 7-11; pl. 3, fig. 12-17.aviatico, ne bergamo, lombardia (italie): rhétien moyen 1996 griphoporella curvata .bernecker, pl. 12, fig. 5.jabal kwar (oman): norien-rhétien 1997 griphoporella curvata .climaco et al., pl. 11, fig. 7.mte rotonda, e maratea, basilicata (italie): norien inférieur-moyen; pl. 11, fig. 8.cala la secca, castrocucco di maratea, basilicata (italie): norien supérieur rhétien; pl. 16, fig. 13 pars.mte rotonda, e maratea, basilicata (italie): norien 1997 griphoporella curvata .grgasoviê, pl. ii, fig. 8 & 13.æumberak mt, ne kraπiê, w zagreb (croatie): rhétien (dolomia principale / hauptdolomit, triasina hantkeni taxon-range zone) 1997 griphoporella curvata .pugliese, pl. 2, fig. 6-9.cima rocca-pietra grande, e madonna di campíglio, gruppo di brenta, trentino alto adige (italie): norien-rhétien 1998 griphoporella curvata .sokaë & grgasoviê, pl. 50, fig. 9.æumberak mt, ne kraπiê, w zagreb (croatie): (? norien supérieur -) rhétien (dolomia principale / hauptdolomit, zone à triasina hantkeni ) 1999 griphoporella curvata .bernecker et al., pl. 39, fig. 8.adnet, hallein, salzburg (autriche): rhétien supérieur griphoporella curvata var . cistiformis zanin buri 1965 [variété superflue ] griphoporella ? guembeli (salomon 1895) pia 1920 [= diplopora gümbeli salomon 1895 ] 1895 diplopora gümbeli n. sp.salomon, pl. i, fig. 20.a-b.marmolada, trentino alto adige véneto (italie): trias ? moyen (wettersteinkalk).types: pl. i, fig. 20.a-b, collection w. salomon, münchen (allemagne) 1920 ? griphoporella gümbeli n. comb.pia, pl. iii, fig. 22-23.marmolada, trentino alto adige véneto (italie): ladinien (marmolatakalk) 1973 griphoporella guembeli .popa & dragastan, pl. xxi, fig. 82-83.dealul ruget remeţi, w valea boiului, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien-ladinien, illyrien supérieur langobardien griphoporella huenzelsauensis e. flügel et hagdorn 1993 1993 griphoporella hünzelsauensis n. sp.e. flügel & hagdorn, pl. 1, fig. 3-7; pl. 2, fig. 1-10.schotterwerk künzelsau-garnberg, künzelsau, baden-württemberg (allemagne): anisien, illyrien (trochitenkalk, zone à ceratites robustus ).holotype: pl. 1, fig. 6 “abgebildete exemplar in schliff a”, collection h. hagdorn, bayerischen staatssamlung für paläontologie und historische geologie, münchen (allemagne) griphoporella spinosa pia 1943, nom. nud. 1943 (nom. nud.) griphoporella n. sp. (gr. spinosa).pia, p. 95, non figurée.type non figurée gyroporella gümbel 1872, emend. benecke 1876 gyroporella aequalis gümbel 1872 [synonyme postérieur de teutloporella herculea (stoppani 1857) pia 1912, d’après ott, 1963 ] 71granier & grgasoviê: les algues dasycladales du permien et du trias... gyroporella ampleforata gümbel 1874 1874 g y r o p o r e l l a a m p l e f o r a t a n. sp.gümbel, p. 79-80, non figurée.pontebba / pontafel, friuli venezia giulia (italie).types ?: collection c.w. gümbel (coll. g. stache), münchen (allemagne) 1912 g y r o p o r e l l a a m p l e f o r a t a .pia, pl. ii(i), fig. 18-21.kar, sw malurch, n pontebba / pontafel, friuli venezia giulia (italie): trias moyen; pl. ii(i), fig. 22-25.lonaswipfel, mte corona / kronalpe, n pontebba / pontafel, friuli venezia giulia (italie): trias moyen; pl. ii(i), fig. 26.e padagozalpe, ne pontebba / pontafel, friuli venezia giulia (italie): trias moyen 1962a g y r o p o r e l l a gr. a m p l e f o r a t a .michard, pl. iv, fig. 4-5.valle di cavoira, val grana, piemonte (italie): ladinien 1964 non gyroporella cf. ampleforata [= poikiloporella duplicata ].bystrický, pl. vii, fig. 3-4 1965 (?) gyroporella cf. ampleforata .herak, pl. xv, fig. 1-2.gradina, vrkljanski ponori, sv. rok, lika (croatie): ladinien; pl. xv, fig. 3.vrace, sw graëac, velebit mt (croatie): ladinien; pl. xv, fig. 4.velika vrπina, sv. rok, lika (croatie): ladinien 1967 g y r o p o r e l l a gr. a m p l e f o r a t a .michard, pl. ix, fig. 4, extrait de michard (1962a: pl. iv, fig. 5); pl. ix, fig. 5, extrait de michard (1962a: pl. iv, fig. 4) 1969 non gyroporella cf. ampleforata [= poikiloporella duplicata ].diaconu & dragastan, pl. iv, fig. 1-2 1972 non g y r o p o r e l l a sp. (g y r o p o r e l l a a m p l e f o r a t a ).bleahu et al., pl. v, fig. 5.vaşcǎu plateau, apuseni mts, bihor (roumanie): anisien moyen-supérieur 1972b g y r o p o r e l l a a m p l e f o r a t a .zorn, fig. 3.4.pontebba / pontafel, friuli venezia giulia (italie): trias moyen 1973 (?) g y r o p o r e l l a cf. a m p l e f o r a t a .kotański & »atalov, pl. xii, fig. 1-6.staneto, s troyan, loveë (bulgarie): anisien terminal ? ladinien basal 1973 g y r o p o r e l l a a m p l e f o r a t a .popa & dragastan, pl. xxi, fig. 84.e valea boiului, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien-ladinien, illyrien supérieur langobardien 1978 (?) gyroporella cf. amplephorata [sic].anelkoviê, pl. lxix, fig. 1, extrait de herak (1965: pl. xv, fig. 1) 1988 (?) g y r o p o r e l l a cf. a m p l e f o r a t a .pfeiffer, pl. 12, fig. 10.gartnerkofel, s hermagor, kärnten (autriche): anisien supérieur gyroporella anisica zanin buri 1965 [cf. anisoporella anisica (zanin buri 1965) hurka 1969 ] gyroporella annulata (schafhäutl 1853) gümbel 1872 [cf. diplopora annulata (schafhäutl 1853) 1863 ] gyroporella balinensis raciborski 1892, nom. nud. [cf. oligoporella pilosa var . balinensis raciborski ex pastwa-leszczyn ´ ska et ś liwiń ski 1960 ] gyroporella bellerophontis rothpletz 1894 [espèce exclue des dasycladales, il s’agit de l’espèce-type du genre gymnocodium pia 1920 ] gyroporella clavata chuvashov 1974 1974 gyroporella clavata n. sp.chuvashov, pl. xiv, fig. 2-5 & 7.rivière chigishan, w y e k a t e r i n b u r g , woural (fédération de russie): assélien; pl. xiv, fig. 1 & 6.riviére chigishan, ou d’après chuvashov et al. (1993): bisert’ river basin, w yekaterinburg (fédération de russie): assélien.holotype: pl. xiv, fig. 2, lame mince n° π 208-77, collection b.i. chuvashov, unt ai sssr [institute of geolo gy and geochemistry of urals, section of russian academy of sciences ], yekaterinburg (fédération de russie) 1979a gyroporella ? clavata .roux, pl. 21, fig. 8-12.n otto fiord, ellesmere, nunavut (canada): artinskien (fm nansen); pl. 21, fig. 13.n otto fiord, ellesmere, nunavut (canada): sakmarien (fm nansen) 1987 gyroporella ? clavata .mamet et al., pl. 21, fig. 8-13, extrait de roux (1979a: pl. 21, fig. 8-13) 1993 gyroporella clavata .chuvashov et al., pl. 14, fig. 12, extrait de chuvashov (1974: pl. xiv, fig. 6); pl. 14, fig. 13, extrait de chuvashov (1974: pl. xiv, fig. 1) 72 geologia croatica 53/1 gyroporella compacta endo 1969 1969 gyroporella compacta n. sp.endo, pl. xvi, fig. 8; pl. xvii, fig. 8-9; pl. xviii, fig. 1 & 4-6.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à c a n c e l l i n a ).holotype: pl. xvii, fig. 8, lame mince n° gk.d 13325, kyūshū university, fukuoka (japon) gyroporella curvata gümbel 1872 [cf. griphoporella curvata ( gümbel 1872) pia 1915, emend. barattolo et al. 1993 ] gyroporella cylindrica gümbel 1872 [synonyme postérieur de diplopora annulata (schafhäutl 1853) 1863, d’après pia, 1912 ] gyroporella debilis gümbel 1872 [cf. kantia debilis (gümbel 1872) baretti 1919, emend. güvenç 1979 ] gyroporella dissecta chuvashov 1974 1974 gyroporella dissecta n. sp.chuvashov, pl. xv, fig. 1, 3-4 & 6.w yekaterinburg, w oural (fédération de russie): assélien; pl. xv, fig. 2 & 5.d’après chuvashov et al. (1993): bisert’ river basin, w yekaterinburg (fédération de russie): assélien.holotype: pl. xv, fig. 5, lame mince n° π 208-88, collection b.i. chuvashov, unt ai sssr [institute of geology and geochemistry of urals, section of russian academy of sciences ], yekaterinburg (fédération de russie) 1979 gyroporella dissecta .zagorodnjuk, pl. ii, fig. 2.voskresenskoye, bashkirskaya (fédération de russie): carbonifère, silésien, gzhélien (c3d) 1982 gyroporella dissecta .mu, pl. vi, fig. 7-10.xizang / tibet (chine populaire): carbonifère, silésien 1993 gyroporella dissecta .chuvashov et al., pl. 14, fig. 15, extrait de chuvashov (1974: pl. xv, fig. 2); pl. 14, fig. 16.bisert’ river, w yekaterinburg (fédération de russie): assélien; pl. 14, fig. 17, extrait de chuvashov (1974: pl. xv, fig. 5) gyroporella dissita gümbel 1872 [cf. physoporella dissita (gümbel 1872) pia 1912 ] gyroporella guatemalense johnson et kaska 1965 1965 gyroporella guatemalense n. sp.johnson & kaska, pl. 3, fig. 3; pl. 4, fig. 1.? san luis (guatemala): p e r m i e n.“type specimen”: pl. 4, fig. 1; “type slide 8343(2)”, collection j.h. johnson, = u.s. national museum no. 042509a, smithsonian institution, washington (états-unis d’amérique) gyroporella hannoensis ishijima et al. 1971 1971 gyroporella hannoensis n. sp.ishijima et al., pl. 11, fig. 7-9.sakaishimachibun, agano-mura, hannōshi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur”.holotype: pl. 11, fig. 7, spécimen n° nsmp1-18128, national science museum, tokyo (japon) gyroporella igoi endo 1959, nom. nud. [“synonyme” de gyroporella nipponica endo et hashimoto 1955, d’après mamet et roux in mamet et al. , 1987] gyroporella infundibuliformis gümbel 1872 [synonyme postérieur de diplopora nodosa schafhäutl 1863, emend. de castro 1979, d’après pia, 1920 ] gyroporella intusannulata kochansky-devidé 1970 1970a gyroporella intusannulata n. sp.kochansky-devidé, pl. xxv, fig. 1-9.gozd-martuljek, e kranjska gora (slovénie): permien inférieur (trogkofelkalk).holotype: pl. xxv, fig. 5, lame mince n° j 296, 73granier & grgasoviê: les algues dasycladales du permien et du trias... collection v. kochansky-devidé, zbirka katedre za geologijo in paleontologijo univerze v ljubljani [sammlung des lehrstuhls für geologie und paläontologie der universität in ljubljana ], ljubljana (slovénie) 1979 gyroporella intusannulata .ramovπ & kochansky-devidé, pl. 1, fig. 5.n julijske alpe (slovénie): artinskien (trogkofelkalk) gyroporella konishii endo 1957 1957 gyroporella konishii n. sp.endo, pl. 39, fig. 9-10.zenbutsuji-dani, taishaku-mura, hiba-gun, hiroshima-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie supérieure).“type” (syntypes): pl. 39, fig. 9, lame mince n° 568; pl. 39, fig. 10, lame mince n° 549, department of earth sciences, saitama university, urawa (japon) gyroporella kwantoensis endo 1956 [synonyme postérieur de gyroporella nipponica endo et hashimoto 1955, d’après endo, 1959 ] gyroporella ladinica bystrický 1962 [synonyme postérieur de poikiloporella duplicata (pia 1920) 1943, d’après ott, 1968 ] gyroporella longipora endo 1951 1951 gyroporella longipora n. sp.endo, pl. 10, fig. 6; pl. 11, fig. 6-7.sakamotozawa, hikoroichi-mura, kesen-gun, iwate-ken, honshū (japon): permien “inférieur”-”moyen”.“cotypes” (syntypes): pl. 10, fig. 6, lame mince n° 34; pl. 11, fig. 6, lame mince n° 8; pl. 11, fig. 7, lame mince n° 32; specimen (?) n° 10765, laboratory (department) of earth sciences, saitama university, urawa (japon) 1954 (?) gyroporella (?) cf. longipora .endo in endo & kanuma, pl. xvi, fig. 2.shimadani valley, hachimanmachi, gujō-gun, gifu-ken, honshū (japon): permien inférieur (shimadani fm, zone à pseudofusulina) gyroporella longithalla endo 1961 1961b gyroporella longithalla n. sp.endo, pl. 10, fig. 2-3.n manganji, santō-machi, sakata-gun, shiga-ken, h o n s hū (japon): permien inférieur (samegai fm); pl. 10, fig. 4-5.w santō-machi, sakata-gun, shigaken, honshū (japon): permien inférieur (samegai fm); pl. 11, fig. 1-2.e o _ nogi, santō-machi, sakatagun, shiga-ken, honshū (japon): permien “moyen” / partie inférieure (o _ nogi fm).holotype: pl. 10, fig. 2, lame mince n° 510606-8, geological survey of japan (japon) 1971 gyroporella longithalla .ishijima et al., pl. 11, fig. 1-2.sakaishimachibun, agano-mura, hannōs h i , iruma-gun, saitama-ken, honshū (japon): permien “inférieur” 1979 gyroporella longithalla .e. flügel, pl. 1, fig. 7.forni avoltri, friuli venezia giulia (italie): permien inférieur (rattendorfer schichten trogkofelkalk) 1980 gyroporella longithalla .e. flügel, pl. 14, fig. 2.reppwand, s hermagor, kärnten (autriche): permien inférieur (trogkofelkalk) 1980 gyroporella longithalla .e. flügel & flügel-kahler, pl. 4, fig. 5.ne col mezzodì, forni avoltri, friuli venezia giulia (italie): permien inférieur (kalkbrekzie) 1982 gyroporella longithalla .mu, pl. vi, fig. 1-2.xizang / tibet (chine populaire): carbonifère, silésien gyroporella macrostoma gümbel 1872 [synonyme postérieur de diplopora annulata (schafhäutl 1853) 1863, d’après pia, 1920 ] gyroporella maxima pia 1920 1920 gyroporella maxima n. sp.pia, pl. i, fig. 27-33.gisement inconnu, ? spitzberg (norvège): ? trias (galet d’origine inconnue).types: pl. i, fig. 27-33, collection j. von pia, naturhistorisches museum, wien (autriche) 1944 gyroporella maxima .johnson, pl. 302, fig. 16, extrait de pia (1920: pl. i, fig. 29); pl. 302, fig. 17, extrait de pia (1920: pl. i, fig. 32); pl. 302, fig. 18, extrait de pia (1920: pl. i, fig. 31); pl. 302, fig. 19, extrait de pia (1920: pl. i, fig. 28) 1965 gyroporella maxima.herak, pl. ii, fig. 4.velika vrπina, sv. rok, lika (croatie): ladinien 74 geologia croatica 53/1 1966 gyroporella maxima .bystrický, pl. v, fig. 4-5; pl. vi, fig. 1.ponická lehôtka poniky oravce postredná môlëa, e banská bystrica (slovaquie): ladinien inférieur (wettersteinkalk) 1973 g y r o p o r e l l a m a x i m a.popa & dragastan, pl. xxi, fig. 85.dealul ruget remeţi, w valea boiului, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien-ladinien, illyrien supérieur langobardien 1986 gyroporella maxima .bystrický, pl. iv, fig. 8-9.poniky, e banská bystrica (slovaquie): ladinien, fassanien (diplopora annulata taxon-range zone) 1987 gyroporella maxima .gaetani et al., pl. i (“in alto”).sasso san martino, esino lario, e lago di como, lombardia (italie): norien gyroporella microporosa endo 1956 gyroporella microporosa var . afghanica vachard in vachard et montenat 1981, non vachard 1980 1974 algues (a).h. termier et al., pl. 37, fig. 4; pl. 38, fig. 1-2.wardak (afghanistan): artinskien (? supérieur) 1 9 8 0 (nom. nud.) g y r o p o r e l l a microporosa afghanica n. subsp.vachard, pl. 7, fig. 7.g; pl. 25, fig. 1 pars.khwahan, tezak (afghanistan): artinskien supérieur.type non désigné 1981 gyroporella microporosa afghanica n. subsp.vachard in vachard & montenat, pl. 4, fig. 1-6 & 10; pl. 6, fig. 4.dacht naw, tezak (afghanistan): sakmarien; pl. 4, fig. 7.khwaja bahadur, tezak (afghanistan): sakmarien; pl. 7, fig. 7 pars.mansur, tezak (afghanistan): artinskien.holotype: pl. 4, fig. 4, lame mince n° ii/123’; paratypes: pl. 4, fig. 1-3, 5-6 & 10, lame mince n° ii/123’ (non pl. 4, fig. 7, lame mince n° iv/374), collection d. vachard, institut de géologie igal, paris (france) gyroporella microporosa var . microporosa vachard in vachard et montenat 1981 [par accident ! ] 1954 gyroporella ( ? ) c f . v e s i c u l i f e r a.endo in endo & kanuma, pl. xvi, fig. 3-4.tominoho-mura, mugigun, gifu-ken, honshū (japon): permien inférieur-moyen (kuchibora fm, zone à parafusulina ); pl. xvi, fig. 5.horikoshi pass, se hachiman-chō, gujō -gun, gifu-ken, honshū (japon): permien inférieurmoyen (kuchibora fm, zone à parafusulina ) 1956 g y r o p o r e l l a m i c r o p o r o s a n. sp.endo, pl. 23, fig. 6-8.sakaishi, agano-mura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne); pl. 23, fig. 9.shōm u r a tōge pass, agano-mura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne); pl. 23, fig. 10.shōw a d e n kō factory, kagemorimura, s chichibu-shi, saitama-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne); pl. 23, fig. 11.hinoda, chichibu-shi, saitama-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne).syntypes: pl. 23, fig. 6, lame mince n° 332; pl. 23, fig. 8, lame mince n° 390; pl. 23, fig. 10, lame mince n° 232; pl. 23, fig. 11, lame mince n° 307, department of earth sciences, saitama university, urawa (japon) 1959 g y r o p o r e l l a m i c r o p o r o s a .endo, pl. 31, fig. 7.sotedani valley, nyūgawa-mura, o _ no-gun, gifu-ken, h o n s hū (japon): permien inférieur-moyen (gonbō fm, zone à p a r a f u s u l i n a / partie inférieure); pl. 32, fig. 3.yokoberadani valley, hatahoko, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien moyen (o _ zu fm, zone à neoschwagerina) 1961b gyroporella microporosa .endo, pl. 11, fig. 10; pl. 12, fig. 6.e o _ nogi, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien “moyen” / partie inférieure (o _ nogi fm); pl. 12, fig. 7.w nagaoka, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm) 1963 gyroporella microporosa .johnson, pl. 58, fig. 6-7, extrait de endo (1956: pl. 23, fig. 6-7) 1969 gyroporella microporosa .endo, pl. xix, fig. 4-9.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina zone à neoschwagerina simplex / partie inférieure) 1969 (?) ? g y r o p o r e l l a m i c r o p o r o s a .endo, pl. xxvii, fig. 4.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina) 1970a g y r o p o r e l l a m i c r o p o r o s a .kochansky-devidé, pl. vii, fig. 7.w karavanke (slovénie): permien inférieur (trogkofelkalk) 1971 (?) g y r o p o r e l l a cf. m i c r o p o r o s a .ishijima et al., pl. 11, fig. 10.sakaishimachibun, agano-mura, hannōshi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur” 75granier & grgasoviê: les algues dasycladales du permien et du trias... gyroporella minuta endo 1969 1969 gyroporella minuta n. sp.endo, pl. xx, fig. 1-6.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina).holotype: pl. xx, fig. 1, lame mince n° gk.d 13032, kyūshū university, fukuoka (japon) gyroporella minutula gümbel 1872 [cf. physoporella minutula (gümbel 1872) pia 1912 ] gyroporella multiporosa endo 1961, nom. nud. 1961b (nom. nud.) gyroporella multiporosa n. sp.endo, pl. 11, fig. 3.muraki, ibuki-mura, santō-machi, sakatagun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 12, fig. 12.e o _ nogi, santōmachi, sakata-gun, shiga-ken, honshū (japon): permien “moyen” / partie inférieure (o _ nogi fm); pl. 13, fig. 8.santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm).“holotype” (syntypes): pl. 11, fig. 3, lame mince n° 510603-1; pl. 13, fig. 8, lame mince n° 510606-b, geological survey of japan (japon) gyroporella multiserialis gümbel 1872 [synonyme postérieur de diplopora annulata (schafhäutl 1853) 1863, d’après pia, 1912 ] gyroporella nipponica endo et hashimoto 1955 1952 g y r o p o r e l l a sp.konishi, pl. 14, fig. 15-16.dodo, n yanahara mine, kitawake-mura, katsuta-gun, okayama-ken, honshū (japon): permien moyen ? supérieur (zone à y a b e i n a, avec n e o s c h w a g e r i n a craticulifera ) 1954 g y r o p o r e l l a sp.endo in endo & kanuma, pl. xvi, fig. 6.nishiwara-mura, gujō -gun, gifu-ken, honshū (japon): permien inférieur-moyen (kuchibora fm, zone à parafusulina ) 1955 g y r o p o r e l l a n i p p o n i c a n. sp.endo & hashimoto, fig. 1.penke river, nishiokoppe-mura, w monbetsu-shi, w abashiri province, hokkaidō (japon): permien (galet dans un conglomérat de la nakaokoppe fm).type: fig. 1, lame mince n° 581 (d’après endo, 1957), department of earth sciences, saita ma university, urawa (japon) 1956 g y r o p o r e l l a k w a n t o e n s i s n. sp.endo, pl. 25, fig. 3-4.usine shōw a d e n kō, kagemori-mura, chichibugun, saitama-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne); pl. 25, fig. 5-7.sakaishi, agano-mura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne); pl. 25, fig. 8.shōm u r a tōge pass, agano-mura, h a n nō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne).syntypes: pl. 25, fig. 3, lame mince n° 223; pl. 25, fig. 4, lame mince n° 232; pl. 25, fig. 6, lame mince n° 336; pl. 25, fig. 7, lame mince n° 330; pl. 25, fig. 8, lame mince n° 368, department of earth sciences, saitama university, urawa (japon) 1957 g y r o p o r e l l a k w a n t o e n s i s.endo, pl. 39, fig. 7-8.zenbutsuji-dani, taishaku-mura, hiba-gun, hiroshima-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie supérieure) 1957 g y r o p o r e l l a n i p p o n i c a.endo, pl. 38, fig. 7-8; pl. 39, fig. 1-6.zenbutsuji-dani, taishaku-mura, hibagun, hiroshima-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie supérieure); pl. 44, fig. 1, extrait de endo & hashimoto (1955: fig. 1); pl. 44, fig. 2.penke river, nishiokoppe-mura, w monbetsu-shi, w abashiri province, hokkaidō (japon): permien (galets dans un conglomérat de la nakaokoppe fm) 1959 g y r o p o r e l l a n i p p o n i c a .endo, pl. 32, fig. 4 & 9.ozudani valley, nyūgawa-mura, o _ no-gun, gifu-ken, h o n s hū (japon): permien inférieur-moyen (o _ zu fm, zone à parafusulina zone à n e o s c h w a g e r i n a); pl. 32, fig. 5.sotedani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien inférieurmoyen (gonbō fm, zone à p a r a f u s u l i n a ); pl. 32, fig. 6 & 8; pl. 33, fig. 3 & 7.hatahoko, nyūg a w a mura, o _ no-gun, gifu-ken, honshū (japon): permien inférieur (gonbō fm, zone à parafusulina = zone à p s e u d o f u s u l i n a); pl. 32, fig. 7.otani, horadani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien (o _ zu fm); pl. 32, fig. 10.chôshidani valley, nyūgawa-mura, o _ no-gun, gifu-ken, h o n s hū (japon): permien (o _ zu fm); pl. 32, fig. 11; pl. 33, fig. 6.gonbō, tochiyamadani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien (o _ zu fm, zone à yabeina); pl. 33, fig. 4.sotedani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien moyen (o _ zu fm, zone à n e o s c h w a g e r i n a); pl. 33, fig. 1.otani, horadani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū 76 geologia croatica 53/1 (japon): permien inférieur (o _ zu fm, zone à p s e u d o f u s u l i n a); pl. 33, fig. 2.hatahoko, nyūg a w a m u r a , o _ no-gun, gifu-ken, honshū (japon): permien inférieur (gonbō fm, zone à pseudoschwagerina ); pl. 33, fig. 5.chôshidani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien inférieurmoyen (gonbō fm, zone à parafusulina ); pl. 40, fig. 1; pl. 42, fig. 6-7.sotedani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien inférieur-moyen (gonbō fm, zone à p a r a f u s u l i n a / partie supérieure) 1 9 5 9 (nom. nud.) gyroporella igoi n. sp.endo, pl. 34, fig. 1-4; pl. 35, fig. 1-5; pl. 40, fig. 3; pl. 41, fig. 7-8.otani, horadani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien inférieur (o _ z u fm, zone à p s e u d o f u s u l i n a); pl. 34, fig. 5.yokoberadani valley, hatahoko, nyūgawa-mura, o _ n o g u n , gifu-ken, honshū (japon): permien moyen (o _ zu fm, zone à neoschwagerina).holotype non explicite ment désigné: pl. 34, fig. 1, 2, 3 et/ou 4, lame mince n° 21128, geol. min. inst., tokyo kyoiku daigaku [tokyo university of education ] (japon) 1961a (nom. nud.) gyroporella igoi .endo, pl. 3, fig. 1, extrait de endo (1959: pl. 41, fig. 8) 1961b g y r o p o r e l l a n i p p o n i c a.endo, pl. 7, fig. 6 & 8; pl. 11, fig. 9.w nagaoka, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 7, fig. 7.sukawa, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 9, fig. 4.forage sengokudani2, sengokudani valley, higashi-kusano-gun, higashi-asai-gun, shiga-ken, honshū (japon): permien “moyen” / partie inférieure (lower takayama fm); pl. 11, fig. 4.n manganji, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 11, fig. 5-6.sukawa, santō m a c h i , sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 11, fig. 7-8.e o _ n o g i , santō-machi, sakata-gun, shiga-ken, honshū (japon): permien “moyen” / partie inférieure (o _ nogi fm) 1961b (nom. nud.) gyroporella igoi .endo, pl. 8, fig. 5-6; pl. 9, fig. 1-2.w nagaoka, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 9, fig. 3.iwakura-yama, sekigaharamachi, fuwa-gun, gifu-ken, honshū (japon): permien “moyen” / partie inférieure (ibukiyama limestone fm) 1961c gyroporella nipponica.endo, pl. 3, fig. 2; pl. 4, fig. 6.wsw mizuta, iwanaga, shuhō-chō, ne mineshi, yamaguchi-ken, honshū (japon): permien inférieur (akiyoshi limestone group, zone à p s e u doschwagerina , sous-zone à triticites simplex); pl. 3, fig. 3.kaerimizu, agako, mitō-chō, ne mine-shi, yamaguchi-ken, honshū (japon): permien moyen (akiyoshi limestone group, zone à p a r a f u s u l i n a , sous-zone à parafusulina kaerimizuensis ); pl. 3, fig. 4.s hagiwara, ofuku, n mine-shi, yamaguchiken, honshū (japon): permien inférieur (akiyoshi limestone group, zone à p s e u d o s c h w a g e r i n a , souszone à pseudofusulina vulgaris ); pl. 3, fig. 5.amagoi-yama, w okugawara, isa, s mine-shi, yamaguchi-ken, honshū (japon): permien supérieur (akiyoshi limestone group, zone à yabeina shiraiwen sis) 1962 (?) g y r o p o r e l l a c f . n i p p o n i c a.kochansky-devidé & milanoviê, pl. vii, fig. 4.krπ, s mojkovac, rivière tara, monténégro (yougoslavie): sakmarien supérieur ou artinskien inférieur 1963 gyroporella kwantoensis.johnson, pl. 58, fig. 8, extrait de endo (1956: pl. 25, fig. 7) 1963 g y r o p o r e l l a n i p p o n i c a.johnson, pl. 58, fig. 9, extrait de endo (1957: pl. 38, fig. 8); pl. 58, fig. 10, extrait de endo (1957: pl. 38, fig. 7) 1965 (nom. nud.) gyroporella igoi .johnson & kaska, pl. 3, fig. 5; pl. 4, fig. 5 & 7.? san luis (guatemala): permien 1 9 6 6 (nom. nud.) gyroporella igoi .johnson & danner, pl. 55, fig. 1 & 3.s mt pilchuck, snohomish county, nw washington (états-unis d’amérique): permien “inférieur” (stillaguamish group); pl. 55, fig. 2.w san juan island, washington (états-unis d’amérique): permien “inférieur” (stillaguamish group) 1966 g y r o p o r e l l a n i p p o n i c a.johnson & danner, pl. 55, fig. 4.s mt pilchuck, snohomish county, nw washington (états-unis d’amérique): permien “inférieur” (stillaguamish group); pl. 55, fig. 5.e jesmond, nw porcupine creek, british columbia (états-unis d’amérique): permien “supérieur” (cache creek group, marble canyon fm) 1966 (?) gyroporella cf. nipponica.rácz, pl. iii, fig. 14-17; pl. iv, fig. 18-19.n cervera de pisuerga, n palencia (espagne): carbonifère, silésien, ouralien (zone à protriticites ) 1968b g y r o p o r e l l a n i p p o n i c a.endo, pl. ii, fig. 2.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien 1 9 6 8 b (nom. nud.) gyroporella igoi .endo, pl. i, fig. 4.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien 1969 gyroporella nipponica.endo, pl. xv, fig. 6; pl. xvi, fig. 5-7; pl. xvii, fig. 1-7.khao phlong phrab, e 77granier & grgasoviê: les algues dasycladales du permien et du trias... phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina zone à neoschwagerina simplex / partie inférieure) 1969 (nom. nud.) gyroporella igoi .endo, pl. xv, fig. 5; pl. xvi, fig. 1-4.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina zone à neoschwagerina simplex / partie inférieure) 1970a g y r o p o r e l l a n i p p o n i c a .kochansky-devidé, pl. xxiv, fig. 1 pars, 2 pars & 3-6.w karavanke (slovénie): permien inférieur (trogkofelkalk) 1971 gyroporella nipponica.ishijima et al., pl. 10, fig. 1-3.sakaishimachibun, agano-mura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur” 1971 (nom. nud.) gyroporella igoi .ishijima et al., pl. 10, fig. 8-10.sakaishimachibun, agano-mura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur” 1 9 7 2 (nom. nud.) gyroporella igoi .homann, pl. 6, fig. 42.nw zottach-kogel, kärnten (autriche): sakmarien (rattendorfer schichten, oberer pseudoschwagerinenkalk) 1974 gyroporella nipponica .chuvashov, pl. xiv, fig. 8; pl. xv, fig. 7-8.w yekaterinburg, w oural (fédération de russie): assélien 1 9 7 7 (nom. nud.) gyroporella igoi .e. flügel, pl. 3/3 pars.treßdorfer alm, kärnten (autriche): sakmarienartinskien (treßdorfer kalk) 1978 gyroporella nipponica .anelkoviê, pl. xxxix, fig. 10, extrait de kochansky-devidé (1970a: pl. xxiv, fig. 1); pl. xxxix, fig. 11, extrait de kochansky-devidé (1970a: pl. xxiv, fig. 5) 1979 gyroporella nipponica .ramovπ & kochansky-devidé, pl. 1, fig. 6.n julijske alpe (slovénie): artinskien (trogkofelkalk) 1979 gyroporella nipponica .zagorodnjuk, pl. ii, fig. 3.voskresenskoye, bashkirskaya (fédération de russie): carbonifère, silésien, gzhélien (c3d) 1980 gyroporella nipponica .e. flügel & flügel-kahler, pl. 4, fig. 2, 4 & 9.n mte covolo / seikofel, ese sesto / sexten, trentino alto adige (italie): permien inférieur (kalkbrekzie) 1980 gyroporella nipponica .ramovπ, fig. 6.1.dolæanova soteska, træië (slovénie): permien inférieur (trogkofelkalk) 1981 gyroporella nipponica.bérczi-makk & kochansky-devidé, pl. iii, fig. 7.forage újfalu-i, s lovászi, n nagykanizsa, zala (hongrie): permien “inférieur” 1981 (?) gyroporella cf. n i p p o n i c a .nakamura, pl. 7, fig. 4.ishiyama, o _ n o c hō tanigumi-mura, gifu-ken, honshū (japon): permien (ishiyama limestone) 1981 g y r o p o r e l l a n i p p o n i c a .ramovπ & kochansky-devidé, pl. 1, fig. 4 pars.s tof, gozd-martuljek kranjska gora (slovénie): permien inférieur (trogkofelkalk) 1982 gyroporella nipponica .mu, pl. vii, fig. 9-10.xizang / tibet (chine populaire): carbonifère, silésien 1984 gyroporella nipponica .nakamura & chisaka, pl. 8, fig. 2-3.mt atagoyama, chôshi-shi, chiba-ken, honshū (japon): permien “supérieur” (takagami conglomerate) 1984 (nom. nud.) gyroporella igoi .nakamura & chisaka, pl. 8, fig. 4-5.mt atagoyama, chôshi-shi, chiba-ken, honshū (japon): permien “supérieur” (takagami conglomerate) 1987 gyroporella nipponica .cati, sartorio & venturini, fig. 2 pars.forage amanda 1 bis, s bibione, offshore veneto (italie): permien inférieur (trogkofelkalk) 1987 gyroporella nipponica .mamet & roux in mamet et al., pl. 22, fig. 3-7.n otto fiord, ellesmere, nunavut (canada): carbonifère, silésien (fm nansen) 1996 gyroporella gr. nipponica.pantiê-prodanoviê, pl. i, fig. 3.gaj, vlaπiê mt, oseëina, w krupanj, serbie (yougoslavie): permien supérieur gyroporella omensis endo 1961, nom. nud. 1961b (nom. nud.) gyroporella omensis n. sp.endo, pl. 10, fig. 1.n manganji, santō-machi, sakata-gun, shigaken, honshū (japon): permien inférieur (samegai fm); pl. 12, fig. 1.s iwasayama, ibuki-mura, santōmachi, sakata-gun, shiga-ken, honshū (japon): permien “moyen” / partie inférieure (ibukiyama limestone fm / partie inférieure); pl. 12, fig. 2.manganji, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 12, fig. 3-4.sukawa, santō-machi, sakata-gun, shiga-ken, h o n s hū (japon): permien inférieur (samegai fm).“holotype” (syntypes): pl. 10, fig. 1, lame mince n° 510604-1; pl. 12, fig. 1, lame mince n° 510524-3 (non 510604-3), geological survey of japan (japon) 78 geologia croatica 53/1 1961c (nom. nud.) gyroporella omensis .endo, pl. 4, fig. 3; pl. 5, fig. 5.s hagiwara, ofuku, n mine-shi, yamaguchi-ken, honshū (japon): permien inférieur (akiyoshi limestone group, zone à pseudoschwagerina , sous-zone à pseudofusulina vulgaris ) 1 9 6 9 (nom. nud.) gyroporella omensis .endo, pl. xv, fig. 7; pl. xviii, fig. 2-3 & 7-9; pl. xix, fig. 1-3.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina zone à neoschwagerina simplex / partie inférieure) 1 9 7 1 (nom. nud.) gyroporella omensis.ishijima et al., pl. 10, fig. 4-7.sakaishimachibun, agano-mura, hannōshi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur” 1974 (?) (nom. nud.) gyroporella omensis.mu, pl. 167, fig. 1.sw chine (chine populaire) 1981 (nom. nud.) gyroporella omensis.nakamura, pl. 7, fig. 5-6.ishiyama, o _ no-chō tanigumi-mura, gifu-ken, honshū (japon): permien (ishiyama limestone) 1984 (nom. nud.) gyroporella omensis.nakamura & chisaka, pl. 8, fig. 6-7.mt atagoyama, chôshi-shi, chibaken, honshū (japon): permien “supérieur” (takagami conglomerate) gyroporella pauciforata gümbel 1872 [cf. physoporella pauciforata (gümbel 1872) steinmann 1903, emend. pia 1912 ] gyroporella plumosa (zanin buri 1965) braga 1986 [= gyroporella vesiculifera var . plumosa zanin buri 1965 ] 1965a gyroporella vesiculifera var. plumosa n. var.zanin buri, pl. 48.a = pl. 51, fig. 3; pl. 48.b.valle imagna, erve, nw bergamo, lombardia (italie): norien (dolomia principale / hauptdolomit).holotype: pl. 48.a = pl. 51, fig. 3, lame mince n° mb-366, coll. n° 1568, collection c. zanin buri, labo ratorio di micropaleontologia, istituto di paleontologia, università di milano (italie) 1986 gyroporella plumosa n. stat.braga, fig. 2.h-k & 2.p.sierra de baza, gor baza, granada (espagne): norien (alpujarride complex, santa barbara unit, carbonate fm, member j) 1987 gyroporella plumosa .braga & martin, pl. i, fig. 9.pico de la carne, sse monachil se la zubia, granada (espagne): norien gyroporella praturloni ishijima et al. 1971 1971 gyroporella praturloni n. sp.ishijima et al., pl. 11, fig. 3-6.sakaishimachibun, agano-mura, hannōshi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur”.holotype: pl. 11, fig. 3, spécimen n° nsmp1-18050a, national science museum, tokyo (japon) 1984 gyroporella praturloni .nakamura & chisaka, pl. 8, fig. 8-10.mt atagoyama, chôshi-shi, chiba-ken, honshū (japon): permien “supérieur” (takagami conglomerate) gyroporella regulata l.t. nguyê n 1970, nom. nud. 1 9 7 0 (nom. nud.) gyroporella regulata n. sp.l.t. nguyên, pl. vii, fig. 3 pars; pl. viii, fig. 8; pl. ix, fig. 2-8.phnom-sup-trup, ne sisophon (cambodge): permien “moyen” (phnom-sup-trup limestones).“holo type” (syntypes): pl. ix, fig. 2, lame mince n° pst 004; pl. ix, fig. 3, lame mince n° pst 008; pl. ix, fig. 4, lame mince n° pst 005, collection saurin, geology department, science faculty of saigon, hô chi minh-ville (viêt nam) gyroporella silesiaca gümbel 1872 [synonyme postérieur de diplopora nodosa schafhäutl 1863, emend. de castro 1979 et/ou de diplopora annulata (schafhäutl 1853) 1863, d’après pia, 1920 ] gyroporella symetrica johnson 1951 [cf. epimastopora symetrica (johnson 1951) roux 1979 ] gyroporella tenuimarginata endo 1956 1956 gyroporella ? tenuimarginata n. sp.endo, pl. 23, fig. 12; pl. 24, fig. 1 & 4.shōw a d e n kō f a c t o r y , kagemori-mura, chichibu-gun, saitama-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne); pl. 24, fig. 2.hinoda, chichibu-shi, saitama-ken, honshū (japon): permien 79granier & grgasoviê: les algues dasycladales du permien et du trias... “inférieur” (yukisawa subsystem / partie moyenne); pl. 24, fig. 3.sakaishi, agano-mura, hannōs h i , iruma-gun, saitama-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne).syntypes: pl. 24, fig. 1 & 4, lame mince n° 286; pl. 24, fig. 2, lame mince n° 307, department of earth sciences, saitama university, urawa (japon) 1957 gyroporella ? t e n u i m a r g i n a t a .endo, pl. 39, fig. 11-12.misaka, shinsaka-mura, jinseki-gun, hiroshima-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne) 1959 gyroporella tenuimarginata .endo, pl. 32, fig. 1-2.hatahoko, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien inférieur (gonbō fm, zone à parafusulina = zone à pseudofusulina) 1962 (?) mizzia ? cf. yabei.kochansky-devidé & milanoviê, pl. vi, fig. 6.krπ, s mojkovac, rivière tara, monténégro (yougoslavie): sakmarien supérieur artinskien inférieur 1965 gyroporella tenuimarginata .kordé, pl. lviii, fig. 4.dorasham 2, dzhul’fa, nakhichevan’ (azerbaïdjan): guadalupien 1965 gyroporella tenuimarginata .ramovπ & kochansky-devidé, pl. x, fig. 1-3.ortnek (slovénie): permien 1970a g y r o p o r e l l a ? t e n u i m a r g i n a t a .kochansky-devidé, pl. vii, fig. 8.w karavanke (slovénie): permien inférieur (trogkofelkalk) 1981 gyroporella tenuimarginata .nakamura, pl. 6, fig. 5; pl. 7, fig. 7.ishiyama, o _ no-chō tanigumi-mura, gifu-ken, honshū (japon): permien (ishiyama limestone) gyroporella triasina (schauroth 1859) gümbel 1872 [cf. euteutloporella triasina (schauroth 1859) de castro 1993 ] gyroporella verticillata kamptner in trauth 1948 [synonyme postérieur de poikiloporella duplicata (pia 1920) 1943, d’après ott, 1974 ] *gyroporella vesiculifera gümbel 1872, emend. benecke 1876 1872 gyroporella vesiculifera n. gen. n. sp.gümbel, pl. d.iii, fig. 15; pl. d.iv, fig. 3.a-e.plusieurs localités: inzino, n gardone val trómpia, e lago d’iseo, lombardia (italie): “dolomite mit avicula exilis stopp. und megalodon complanatus” et/ou bezzecca, val di ledro, n lago di garda, trentino alto adige (italie).types: pl. d.iii, fig. 15; pl. d.iv, fig. 3.a-e, collection c.w. gümbel (coll. prof. pichler), münchen (allemagne) 1876 gyroporella vesiculifera emend.benecke, pl. xxiii(3), fig. 6 & 9-11.inzino, n gardone val trómpia, e lago d’iseo, lombardia (italie); pl. xxiii(3), fig. 7 & 12.san michele, n tremósine, w lago di garda, lombardia (italie) 1887 gyroporella vesiculifera .solms-laubach, fig. 4.c, extrait de benecke (1876: pl. xxiii(3), fig. 6); fig. 4.d, extrait de benecke (1876: pl. xxiii(3), fig. 12); fig. 4.e, extrait de benecke (1876: pl. xxiii(3), fig. 7) 1890 gyroporella vesiculifera .schimper & schenk, fig. 31, n° 3, extrait de benecke (1876: pl. xxiii(3), fig. 6); fig. 31, n° 4, extrait de benecke (1876: pl. xxiii(3), fig. 12); fig. 31, n° 5, extrait de benecke (1876: pl. xxiii(3), fig. 7) 1907 gyroporella vesiculifera .steinmann, fig. 11.a.inzino, n gardone val trómpia, e lago d’iseo, lombardia (italie): trias supérieur (dolomia principale / hauptdolomit) 1915 (?) gyroporella vesiculifera .négris, fig. 3-3’ & 4-4’.kythnos (grèce): trias; pl. vii; pl. ix, fig. g-g’.kaessariani (grèce): trias; pl. ix, fig. ß-ß’.zoodochos pighi (grèce): trias 1919 (?) gyroporella vesiculifera .négris, pl. xxviii, fig. 5-6.(grèce): trias; pl. xxx, fig. 1-4.athínai, attikí (grèce): trias 1920 gyroporella vesiculifera .pia, pl. ii, fig. 4 & 6-8.val d’ámpola, ne lago d’idro, trentino alto adige (italie): norien (dolomia principale / hauptdolomit); pl. ii, fig. 5.mte guárdia, w lago di garda, lombardia (italie): norien (dolomia principale / hauptdolomit) 1954 gyroporella vesiculifera .conti, pl. ii, fig. 10.mte castellar, val grana, piemonte (italie): norien 1954 non gyroporella (?) cf. vesiculifera [= gyroporella microporosa var. microporosa].endo in endo & kanuma, pl. xvi, fig. 3-5 1964 gyroporella vesiculifera .sokaë et al., fig. 3.1-2.vrace, sw graëac, velebit mt (croatie): norien 80 geologia croatica 53/1 1965a gyroporella vesiculifera var. v e s i c u l i f e r a n. var.zanin buri, pl. 46, fig. 1-2; pl. 47.castione della presolana, ne bergamo, lombardia (italie): norien (dolomia principale / hauptdolomit) 1967b (?) g y r o p o r e l l a ex aff. v e s i c u l i f e r a.bystrický, pl. iv, fig. 4.n muráňska huta, muráňska planina (slovaquie): norien terminal ? rhétien basal 1970 (?) gyroporella aff. vesiculifera.patrulius, pl. v, fig. 1-2.piatra şoimului, mt rarǎu, suceava (roumanie): norien 1973 gyroporella vesiculifera .kotański & »atalov, pl. xii, fig. 7-11.zessidren, s teteven, loveë (bulgarie): norien 1974 gyroporella vesiculifera .pantiê, pl. v, fig. 4-5.ruisseau ljubeniê, prokletije mts, kosovo, serbie (yougoslavie): carnien 1975 gyroporella vesiculifera .e. flügel, pl. 4, fig. 4.w julijske alpe (slovénie): norien-rhétien (dachsteinkalk) 1978 gryphoporella vesiculifera [s i c].bousquet et al., pl. iii, fig. 2 pars.timpone del convento, s campo tenese, e mormanno, calabria (italie): norien terminal 1978 gyroporella parvovesiculifera [s i c].bousquet et al., pl. ii, fig. 4 pars.timpone san sagaria, nne morano calabro, calabria (italie): norien terminal 1978 gyroporella vesiculifera .bousquet et al., pl. iii, fig. 3 & 4 pars.timpone del convento, s campo tenese, e mormanno, calabria (italie): norien 1980a gyroporella vesiculifera .dullo, pl. 1, fig. 1.2.d’après dullo & lein (1982): kreuzkogel, se admont, gesäuse, steiermark (autriche): carnien (leckkogelschichten) 1980b gyroporella vesiculifera .dullo, pl. 10, fig. 9, extrait de dullo (1980a: pl. 1, fig. 1 pars) 1982 gyroporella sp.dronov et al., pl. 15, fig. 3.karauldyndala, se pamir (tadzikistan): sévatien inférieur (kamarutek fm) 1982 gyroporella vesiculifera .dullo & lein, pl. 4, fig. 5 pars, extrait de dullo (1980a: pl. 1, fig. 1) 1982 (?) gyroporella cf. g. vesiculifera.e. flügel & mu, pl. 9, fig. 1-2.jomda, qambdo district, e xizang / tibet (chine populaire): carnien (jiapeila fm) 1982 gyroporella vesiculifera .schäfer & senowbari-daryan, pl. 19, fig. 3 pars.didymi mts, argolís (grèce): carnien (pantokrator limestones) 1983 gyroporella vesiculifera .schäfer & senowbari-daryan, pl. 6, fig. 1 & 2 pars (1).didymi mts, argolís (grèce): trias supérieur 1985 gyroporella vesiculifera .p. di stefano & senowbari-daryan, fig. 4.capo rama, terrasini, w palermo, sicile (italie): norien 1987 non gyroporella vesiculifera [= griphoporella curvata ].ciarapica et al., pl. xxiii, fig. 1-10; pl. xxv, fig. 1.a [= pl. xxiii, fig. 5]; pl. xxv, fig. 1.b, 3.a, 4.a, 5.a & 6.a 1987 non gyroporella vesiculifera [= griphoporella curvata ].gaetani et al., pl. i (“in basso”) 1989 (?) gyroporella cf. v e s i c u l i f e r a.bukovac & sokaë, pl. i, fig. 1-2.oπtrc, gorjanci mt, s kostanjevica (slovénie): trias supérieur, ? rhétien 1997 gyroporella vesiculifera .pugliese, pl. 2, fig. 1-5.cima rocca, e madonna di campíglio, gruppo di brenta, trentino alto adige (italie): norien gyroporella vesiculifera var . plumosa zanin buri 1965 [cf. gyroporella plumosa (zanin buri 1965) braga 1986 ] gyroporella vesiculifera var . vesiculifera zanin buri 1965 [variété créée par accident, mais superflue du fait du changement de statut de la variété plumosa zanin buri 1965 ] gyroporella watanabei nakamura et chisaka 1984, nom. nud. 1984 (nom. nud.) gyroporella watanabei n. sp.nakamura & chisaka, pl. 8, fig. 11-17.mt atagoyama, chôshishi, chiba-ken, honshū (japon): permien “supérieur” (takagami conglomerate).syntypes: pl. 8, fig. 11, lame mince n° nsm-pp 7950a; pl. 8, fig. 15, lame mince n° nsm-pp 7910e; pl. 8, fig. 16, lame mince n° nsm-pp 7950b, national science museum, tokyo (japon) 81granier & grgasoviê: les algues dasycladales du permien et du trias... halicoryne harvey 1859 halicoryne carpatica mi©ík 1987, nom. nud. 1965 acicularien.schalekova, pl. xxxviii, fig. 1.mt zvolen, n donovaly, nízke tatry (slovaquie): rhétien 1966 acicularia.miπík, pl. xi, fig. 1.a-b.hybe, nízke tatry (slovaquie): norien; pl. xi, fig. 1.d.mt holica, huty, tatry (slovaquie): trias supérieur, ? carnien; pl. xi, fig. 2.mt zvolen, n donovaly, nízke tatry (slovaquie): rhétien 1975 halicoryne sp.borza, pl. vi, fig. 7 & 10-11.tepliëné, w tisovec, muráňska planina (slovaquie): norien (dachsteinkalk); pl. vi, fig. 8.goπtanová, w tisovec, muráňska planina (slovaquie): norien (dachsteinkalk); pl. vi, fig. 9.javorina vel’ká lúka, w tisovec, muráňska planina (slovaquie): norien (dachsteinkalk) 1976 halicoryne sp.marschalko et al., pl. xxiv, fig. 5-6.hromoπ, nw lipany se stará l’ubovna (slovaquie): rhétien (galet dans un conglomérat paléogène) 1976 halicoryne sp.miπík & borza, pl. xix, fig. 7.silická brezová, slovenský kras (slovaquie): norien (hallstätter kalk) 1978 c h a l m a s i a sp.istocescu & dragastan, pl. iv, fig. 3-4.hidişel, apuseni mts (roumanie): ladiniencarnien ? norien 1980 (?) acicularia ? sp.senowbari-daryan, pl. 14, fig. 8.feichtenstein, hintersee, salzburg (autriche): rhétien supérieur 1987 (?) halicoryne sp. 2.miπík, pl. i, fig. 7.boπáca (slovaquie): carnien supérieur (galet dans un conglomérat albien); pl. i, fig. 9; pl. ii, fig. 1.donovaly, nízke tatry (slovaquie): rhétien; pl. i, fig. 6, extrait de miπík (1966: pl. xi, fig. 1.d); pl. i, fig. 10, extrait de miπík (1966: pl. xi, fig. 2 pars) 1987 (nom. nud.) halicoryne carpatica n. sp.miπík, pl. i, fig. 1, extrait de marschalko et al. (1976: pl. xxiv, fig. 5); pl. i, fig. 3, extrait de marschalko et al. (1976: pl. xxiv, fig. 6); pl. i, fig. 2; pl. ii, fig. 3.hromoπ, nw lipany se stará l’ubovna (slovaquie): rhétien (galet dans un conglomérat paléogène); pl. i, fig. 5.neporádza (slovaquie): trias supérieur (hauptdolomit); pl. i, fig. 11.jablonové, w æilina (slovaquie): norien (galet dans un conglomérat paléogène); pl. ii, fig. 2.huty, tatry (slovaquie): norien; pl. i, fig. 4, extrait de miπík (1966: pl. xi, fig. 1.a pars).“holotype” (syntypes): pl. ii, fig. 2, lame mince n° 63941/f, recélant plusieurs spécimens, department of geology and paleontology, comenius university, bratislava (slovaquie) 1987 (?) dasycladacea.oravecz-scheffer, pl. xxv, fig. 2.forage porva 89, balaton (hongrie): norien (dachsteinkalk) 1988 aciculella sp.»anoviê & kemenci, pl. xi, fig. 1.forage bajπa-3 (ba-3), bajπa, vojvodina, serbie (yougoslavie): carnien 1988 (?) algae gen. indet. 2.vachard in fontaine & suteethorn, pl. 19, fig. 3.ban chake, kanchanaburi, w krung thep / bangkok (thaïlande): trias supérieur heteroporella cros et lemoine ex praturlon 1967, emend. granier et al. 1995 heteroporella carpatica bystrický 1967 [cf. chinianella carpatica (bystrický 1967) granier et al. 1995 ] heteroporella crosi ott 1968, non 1967 [cf. chinianella crosi (ott 1968) granier et al. 1995 ] heteroporella macropora p. di stefano ex p. di stefano et senowbari-daryan 1985 [cf. chinianella macropora (p. di stefano ex p. di stefano et senowbari-daryan 1985) granier et al. 1995 ] 82 geologia croatica 53/1 heteroporella micropora p. di stefano ex p. di stefano et senowbari-daryan 1985 [cf. chinianella micropora (p. di stefano ex p. di stefano et senowbari-daryan 1985) granier et al. 1995 ] heteroporella zankli ott 1968, non 1967 [synonyme postérieur de chinianella carpatica (bystrický 1967) granier et al. 1995 ] imperiella elliott in granier et deloffre 1995, non in elliott et süssli 1975 imperiella afghanica vachard in granier et deloffre 1995, non in vachard et montenat 1981, non 1980 1 9 8 0 (nom. nud.) imperiella afghanica n. sp.vachard, pl. 5, fig. 5 pars.al-e say, tezak (afghanistan): kubergandienmurghabien inférieur; pl. 24, fig. 9.tezak khwaja bahadur, tezak (afghanistan): kubergandien; pl. 35, fig. 8.col du shebar, w hindou kouch (afghanistan): kubergandien.type non désigné 1 9 8 1 (nom. nud.) imperiella afghanica n. sp.vachard in vachard & montenat, pl. 5, fig. 13, extrait de vachard (1980: pl. 24, fig. 9).holotype: pl. 5, fig. 13, lame mince iva/493 (ml 4211), collection m. lys, institut de géologie igal, paris (france) 1 9 8 4 (?) (nom. nud.) imperiella sp.e. flügel, kochansky-devidé & ramovπ, pl. 29, fig. 12.straæa, bled (slovénie): permien “moyen” 1995 imperiella afghanica .vachard in granier & deloffre, p. 57, non figurée.validation de l’espèce *imperiella iranica elliott in granier et deloffre 1995, non in elliott et süssli 1975 1 9 7 5 (nom. nud.) imperiella iranica n. gen. n. sp.elliott & süssli, pl. i, fig. 1-3.emarat, central alborz mts (iran): permien “supérieur” (ruteh limestone) .syntypes: pl. i, fig. 1 & 3, lame mince v.57669; pl. i, fig. 2, lame mince v.57671, collection g.f. elliott, british museum (natural history), london (royaume-uni) 1988 (nom. nud.) imperiella iranica .deloffre, pl. 10, fig. 22, extrait de elliott & süssli (1975: pl. i, fig. 1) 1989 (?) imperiella sp.d.t. nguyên, pl. 25, fig. 9.lubuk cada, batang tabir, sumatra (indonésie): murghabien 1 9 9 0 (?) (nom. nud.) imperiella cf. i r a n i c a .e. flügel, pl. 3, fig. 2 pars, 3 pars & 6.kapiskaya, ne kinik, sse balya (turquie): murghabien (zone à neoschwagerina / partie moyenne) 1 9 9 2 (?) (nom. nud.) i m p e r i e l l a c f . i r a n i c a .vachard et al., pl. iii, fig. 2 pars.s doi luang mts, nw thaïlande (thaïlande): bolorien 1995 imperiella iranica .elliott in granier & deloffre, p. 57, non figurée.typification et validation de l’espèce; lectotype: pl. i, fig. 1 in elliott & süssli (1975), lame mince n° v.57669, british museum (natural history), london (royaume-uni) johnsonia kordé 1965, nom. nud. [“synonyme” de likanella milanovi∆ in granier et deloffre 1995, non 1966 ] *johnsonia spinosa kordé 1965, nom. nud. [“synonyme” de likanella spinosa milanovi∆ in granier et deloffre 1995, non 1966 ] kantia pia 1912, emend. güvenç 1979 kantia ? brunoi baretti 1919 [synonyme postérieur de kantia philosophi (pia 1912) güvenç 1979 ] 83granier & grgasoviê: les algues dasycladales du permien et du trias... kantia crassipora bubnof 1921 [synonyme postérieur de diplopora annulata (schafhäutl 1853) 1863, d’après pia in hirmer, 1927 ] kantia debilis (gümbel 1872) baretti 1919, emend. güvenç 1979 [= diplopora annulata var. [“subsp.” ] dolomitica (pia 1912) herak 1957 [pars ]; = diplopora annulata var. debilis (forma vesiculifera) (gümbel 1872) pia 1920; = diplopora debilis (gümbel 1872) pia 1912; = gyroporella debilis gümbel 1872 ] 1872 gyroporella debilis n. sp.gümbel, pl. d.ii, fig. 3.a-b.mendola, trentino alto adige (italie): trias moyen (mendoladolomit).types: pl. d.ii, fig. 3.a-b, collection c.w. gümbel (coll. prof. pichler), münchen (allemagne) 1912 diplopora debilis n. comb.pia, pl. viii(vii), fig. 3.mittereckalm, tweng, taurach, salzburg (autriche): trias ? moyen (wettersteinkalk, tauerndolomit); pl. viii(vii), fig. 4-7.tweng, taurach, salzburg (autriche): trias ? moyen (wettersteinkalk, tauerndolomit) 1915a diplopora debilis .pia in spitz & dyhrenfurt, pl. i, fig. 12.piz starler, scarltal, unter-engadin, graubünden (suisse): ladinien (wettersteindolomit) 1919 kantia debilis n. comb.baretti, fig. 2 & 2.a-d.villanova mondovi, mondovi, piemonte (italie): trias 1920 diplopora annulata var. debilis (forma vesiculifera) n. stat. n. comb.pia, p. 79, non figurée 1920 non diplopora annulata var. debilis (forma trichophora) n. stat. n. comb. [= diplopora annulata ].pia, pl. v, fig. 24 1957 (pars) diplopora annulata subsp. dolomitica n. stat.herak, p. 52, non figurée 1962b (?) diplopora annulata var. d e b i l i s.michard, pl. vii, fig. 2.case solano, valle di cavoira, val grana, piemonte (italie): anisien terminal ladinien 1962b non diplopora annulata var. debilis [= kantia dolomitica].michard, pl. vi, fig. 1-2; pl. vii, fig. 1 1962b (?) diplopora annulata ? var. d e b i l i s.michard, pl. ix, fig. 2 pars.case solano, valle di cavoira, val grana, piemonte (italie): anisien terminal ladinien 1965a diplopora annulata var. debilis, forma vesiculifera.zanin buri, pl. 56; pl. 57, fig. 1.a-b & 2.cugno di sotto, valle brembana, n bergamo, lombardia (italie): ladinien moyen-supérieur (esinokalk / fm del calcare di esino) 1965a non diplopora annulata var. debilis, forma trichophora [= diplopora annulata ].zanin buri, pl. 57, fig. 1.c 1969 diplopora annulata var. d e b i l i s.diaconu & dragastan, pl. vi, fig. 1-2.dealul glimeia, apuseni mts (roumanie): ladinien; pl. vii, fig. 4.valea crişului repede, apuseni mts, bihor (roumanie): ladinien 1979 kantia debilis emend.güvenç, p. 631, non figurée kantia dolomitica pia 1912, emend. güvenç 1979 [= diplopora annulata var. [“subsp.” ] dolomitica (pia 1912) herak 1957 [pars ]; = diplopora annulata var. dolomitica (forma vesiculifera) (pia 1912) 1920 ] 1912 kantia dolomitica n. sp.pia, pl. vi(v), fig. 14-16.val sorda, látemar, trentino alto adige (italie): trias moyen (schlerndolomit).types: pl. vi(v), fig. 14, lame mince n° xxx/1; pl. vi(v), fig. 15-16, lame mince n° xxx/4, collection j. von pia, naturhistorisches museum, wien (autriche) 1919 kantia dolomitica.baretti, fig. 5.garavagna, mondovi, piemonte (italie): trias 1920 diplopora annulata var. d o l o m i t i c a (forma vesiculifera) n. stat. n. comb.pia, pl. v, fig. 18-19.crnopac, graëac, velebit mt (croatie): ladinien; pl. v, fig. 21.esino lario, e lago di como, lombardia (italie): ladinien (esinokalk / fm del calcare di esino); pl. v, fig. 26.velika strana, velebit mt (croatie): ladinien; pl. v, fig. 27.halan, smolëiê, velebit mt (croatie): ladinien 1920 non diplopora annulata ? var. d o l o m i t i c a (forma trichophora) n. stat. n. comb [= diplopora annulata ].pia, pl. v, fig. 22 1 9 2 0 (nom. nud.) diplopora annulata var. s e p t e m t r i o n a l i s (forma vesiculifera) n. var.pia, pl. v, fig. 17.steinbach am attersee, höllengebirge, oberösterreich (autriche): ladinien (wettersteinkalk).1 des types: pl. v, fig. 17, lame mince n° ?, collection j. von pia, naturhistorisches museum, wien (autriche) 1921 non kantia dolomitica var. subannulata n. var. [= diplopora annulata ].bubnoff, pl. x, fig. 4-7.types: pl. x, fig. 4-7 1925 diplopora annulata var. d o l o m i t i c a.pia, pl. i, fig. 4.mali halan sv. rok, velebit mt (croatie): anisien 84 geologia croatica 53/1 1944 diplopora annulata .johnson, pl. 302, fig. 3, extrait de pia (1920: pl. v, fig. 21); pl. 302, fig. 4, extrait de pia (1920: pl. v, fig. 27); pl. 302, fig. 5, extrait de pia (1920: pl. v, fig. 26) 1957 (pars) diplopora annulata subsp. dolomitica n. stat.herak, p. 52, non figurée 1962b diplopora annulata var. debilis.michard, pl. vi, fig. 1-2; pl. vii, fig. 1.case solano, valle di cavoira, val grana, piemonte (italie): anisien terminal ladinien 1962b algues.michard, pl. x, fig. 2 pars.case solano, valle di cavoira, val grana, piemonte (italie): anisien terminal ladinien 1963 diplopora annulata .ott, fig. 3-6, 10 & 15.karwendelgebirge, tirol (autriche): ladinien (wettersteinkalk) 1964 d i p l o p o r a a n n u l a t a var. d o l o m i t i c a.bystrický, pl. xxix, fig. 5; pl. xxx, fig. 1-3 & 6; pl. xxxi, fig. 2-5.slovenský kras (slovaquie): ladinien; pl. xxx, fig. 4-6; pl. xxxi, fig. 1.zádielska planina, s varhút, slovenský kras (slovaquie): ladinien (wettersteinkalk) 1964 diplopora annulatissima .bystrický, pl. xxvi, fig. 1.slovenský kras (slovaquie): anisien supérieur 1965 diplopora annulata subsp. dolomitica.herak, pl. vi, fig. 1.gradina, vrkljanski ponori, sv. rok, lika (croatie): ladinien 1966 diplopora annulata var. dolomitica.bystrický, fig. 2.a-j; pl. viii, fig. 5-6.ponická lehôtka poniky oravce postredná môlëa, e banská bystrica (slovaquie): ladinien (wettersteinkalk) 1966 diplopora annulata .ott, fig. 1, 5 pars (1f, 2e, 3b, 3e, 4a, 4b & 5c) & 7.schlauchkar, karwendelgebirge, tirol (autriche): ladinien (wettersteinkalk); fig. 2, extrait de ott (1963: fig. 10) 1967 diplopora annulata subsp. d o l o m i t i c a.michard, pl. vii, fig. 1, 3 & 6.case solano, valle di cavoira, val grana, piemonte (italie): ladinien; pl. vii, fig. 2, extrait de michard (1962b: pl. vi, fig. 1); pl. vii, fig. 4, extrait de michard (1962b: pl. vii, fig. 1); pl. vii, fig. 5, extrait de michard (1962b: pl. vi, fig. 2) 1969 diplopora annulata .bloch & lefevre, pl. i, fig. 1-3 & 10-12.val de preit, bric bernoir, col del mulopasso della gardetta, bersezio, piemonte (italie): ladinien 1969 diplopora annulata var. d o l o m i t i c a.diaconu & dragastan, pl. vi, fig. 5-7.dealul glimeia, apuseni mts (roumanie): ladinien 1973 diplopora annulata var. d o l o m i t i c a.kotański, pl. vi, fig. 4 pars.tiesniawy gorge, koryciska scale, juránová valley, se oravice, tatry (slovaquie): ladinien (wettersteindolomit) 1973 diplopora annulata forma vesiculifera.popa & dragastan, pl. xvii, fig. 65-68; pl. xviii, fig. 72 pars.dealul ruget remeţi, w valea boiului, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisienladinien, illyrien supérieur langobardien 1 9 7 3 (?) (nom. nud.) physoporella likana .popa & dragastan, pl. xix, fig. 73.dealul ruget remeţi, w valea boiului, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien-ladinien, illyrien supérieur langobardien 1974 diplopora annulata .sokaë, pl. v, fig. 5-6.w rastovaëa, graëac, velebit mt (croatie): ladinien inférieur 1975 (?) d i p l o p o r a .zawidzka, pl. 27, fig. 1-2.kamień śla̧ski, ene góraz°dz°e, se opole, haute silésie (pologne): anisien, illyrien (karchowice fm) 1976 diplopora annulata forma vesiculifera.hanáëek, pl. viii, fig. 2 pars & 3 pars.stráæovské vrchy, e trencín (slovaquie): ladinien (wettersteinkalk) 1979 diplopora annulata v a r . d o l o m i t i c a.fois, pl. 3, fig. 6-7, 10.b & 11; pl. 6, fig. 1-8.mte popera, rocca di campo bivacco piovan, belluno, véneto (italie): anisien, illyrien (“algal limestones”, a v i a s i a n u s zone) 1979 kantia dolomitica emend.güvenç, p. 631, non figurée 1979 diplopora annulata dolomitica .kotański, pl. 80, fig. 2.a-d.tatry (pologne): ladinien inférieur; pl. 80, fig. 10-12 & 14.tatry (pologne): ladinien inférieur 1980 diplopora annulata .dragastan, pl. v, fig. 4, extrait de popa & dragastan (1973: pl. xvii, fig. 65); pl. v, fig. 6, extrait de popa & dragastan (1973: pl. xvii, fig. 66); pl. v, fig. 7, extrait de diaconu & dragastan (1969: pl. vi, fig. 6); pl. vi, fig. 2.ruget, pǎdurea craiului, apuseni mts, bihor (roumanie): ladinien; pl. vi, fig. 8 pars, extrait de popa & dragastan (1973: pl. xvii, fig. 68); pl. vii, fig. 1-2.forage sterpinoasa, pǎdurea craiului, apuseni mts, bihor (roumanie): ladinien 1981 diplopora annulata .dragastan, pl. 9, fig. 2, extrait de popa & dragastan (1973: pl. xvii, fig. 65) 1986 diplopora annulata annulata .kotański, pl. cv, fig. 2, extrait de pia (1920: pl. v, fig. 21) 85granier & grgasoviê: les algues dasycladales du permien et du trias... 1986 diplopora annulata dolomitica .kotański, pl. civ, fig. 2.a-d, 10-12 & 14, extrait de kotański (1979: pl. 80, fig. 2.a-d, 10-12 & 14) 1991 diplopora annulata .barattolo, pl. iii, fig. 2.graëac, velebit mt (croatie): trias moyen kantia dolomitica var. subannulata bubnof 1921 [synonyme postérieur de diplopora annulata (schafhäutl 1853) 1863, d’après ott, 1974 ] kantia hexaster pia 1912 [cf. poncetella hexaster (pia 1912) güvenç 1979 ] kantia j. v. piae reis 1926 [synonyme postérieur de diplopora annulatissima pia 1920, d’après pia in hirmer, 1927; cf. kantia monregalensis baretti 1919 ] kantia monregalensis baretti 1919 1919 diplopora annulata .baretti, fig. 1 & 1.a.villanova mondovi, mondovi, piemonte (italie): trias 1919 kantia monregalensis n. sp.baretti, fig. 6 & 6.a-c.mte calvario, mondovi, piemonte (italie): trias. types: fig. 6 & 6.a-c 1920 diplopora annulatissima n. sp.pia, pl. iv, fig. 11-16.mythen, zweckenalp, schwyz (suisse): trias moyen, ? anisien (calcaire à diplopores).types: pl. iv, fig. 11-16, lames minces n° ?, collection j. von pia, naturhistorisches museum, wien (autriche) 1925 diplopora annulatissima .pia, pl. i, fig. 1-3.veligrad, n crni rt, sutomore, monténégro (yougoslavie): anisien 1926 kantia j. v. piae n. sp.reis, pl. ii, fig. 39-42.ehrwald, zugspitze, tirol (autriche): ladinien.types: pl. ii, fig. 39-42 1927 diplopora annulatissima .ogilvie gordon, pl. ix, fig. 1-3; pl. x, fig. 7-12.trentino alto adige (italie): trias 1931 d i p l o p o r a a n n u l a t i s s i m a .pia, pl. xxi, fig. 1.nowe koszyce / neu-koschütz, nw strzelce opolskie, haute silésie (pologne): anisien, illyrien (jemielnica fm / himmelwitzdolomit); pl. xxi, fig. 2.sztolnia gl⁄ ȩboka-fryderyk (czarny pstrag) / tiefen friedrichsstollen, s tarnowskie góry / tarnowitz, haute silésie (pologne): anisien, illyrien (jemielnica fm / himmelwitzdolomit) 1950 diplopora annulatissima .herak, pl. ii, fig. 4; pl. iii, fig. 2.mali halan-smolëiê vrh, velebit mt (croatie): ladinien; pl. iii, fig. 3; pl. iv, fig. 1 pars & 2.grgin brijeg, velebit mt (croatie): ladinien 1950 non diplopora annulatissima [= diplopora annulata ].herak, pl. ii, fig. 3 1957 diplopora annulatissima .bystrický, pl. vii, fig. 3.kolísky, stratenská hornatina mts (slovaquie): anisien, illyrien supérieur 1958 (?) diplopora cf. annulatissima .ellenberger, pl. 6, fig. 20-21.roc de la pêche, vanoise, savoie (france): “virglorien” (anisien) 1958 diplopora annulatissima .mahel’, pl. ix, fig. 4, extrait de bystrický (1957: pl. vii, fig. 3) 1959 diplopora annulatissima .bystrický, pl. xi, fig. 1-3; pl. xii, fig. 1-5.domica keëovo, se pleπivec, slovenský kras (slovaquie): anisien 1961 diplopora annulatissima .botteron, pl. vii, fig. 1.mont d’or, vaud (suisse): “virglorien” (anisien) supérieur 1961a diplopora annulatissima .endo, pl. 4, fig. 9, extrait de pia (1925: pl. i, fig. 3) 1961 diplopora annulatissima .johnson, pl. 52, fig. 2-3, extrait de pia (1920: pl. iv, fig. 12 & 14) 1963 diplopora annulatissima .herak, fig. 38.sv. rok, lika (croatie): trias moyen 1964 diplopora annulatissima .bystrický, pl. xxiv, fig. 4-5; pl. xxv, fig. 4; pl. xxvi, fig. 3-4; pl. xxvii, fig. 1-3; pl. xxviii, fig. 1-4.slovenský kras (slovaquie): anisien supérieur; pl. xxv, fig. 1.domica keëovo, se pleπivec, slovenský kras (slovaquie): anisien-ladinien, illyrien-fassanien, ou d’après miπík (1966): anisien, illyrien supérieur, ou d’après bystrický (1986): anisien-ladinien, illyrien-fassanien (physoporella pauciforata oligoporella pilosa assemblage zone, diplopora annulatissima p a rtial range zone et diplopora annulata taxon-range zone); pl. xxv, fig. 2.d’après miπík (1966): domica keëovo, se pleπivec, slovenský kras (slovaquie): anisien, illyrien supérieur; pl. xxv, fig. 3, extrait 86 geologia croatica 53/1 de bystrický (1959: pl. xii, fig. 2); pl. xxvi, fig. 2, extrait de bystrický (1959: pl. xi, fig. 3); pl. xxvii, fig. 4, extrait de bystrický (1959: pl. xi, fig. 2) 1964 non diplopora annulatissima [= kantia dolomitica].bystrický, pl. xxvi, fig. 1 1965 diplopora annulatissima .herak, pl. v, fig. 3.hrastova kosa, sv. rok, lika (croatie): ladinien; pl. v, fig. 4.rukavinska gradina, sv. rok, lika (croatie): ladinien; pl. vii, fig. 1, extrait de herak (1963: fig. 38); pl. vii, fig. 2.n vrbani, sv. rok, lika (croatie): trias moyen; pl. xii, fig. 7 pars.velika vrπina, sv. rok, lika (croatie): ladinien 1965 diplopora annulatissima .schalekova, pl. xxxvii, fig. 1.domica keëovo, se pleπivec, slovenský kras (slovaquie): anisien, illyrien 1966 diplopora annulatissima .bystrický, pl. viii, fig. 4.ponická lehota poniky oravce môlëa, sw banska bystrica (slovaquie): trias moyen, ? passage anisien-ladinien (en éboulis, ? wettersteinkalk) 1966 diplopora annulatissima .miπík, pl. iii, fig. 2 pars, extrait de bystrický (1964: pl. xxv, fig. 1-2) 1966 diplopora annulatissima .ott, fig. 4 pars & 5 pars (4f).schlauchkar, karwendelgebirge, tirol (autriche): ladinien (wettersteinkalk) 1967 diplopora annulatissima .rossi, fig. 70.marmolada, trentino alto adige (italie): anisien moyensupérieur (calcare di contrin) 1968 diplopora annulatissima .mégard-galli, fig. 6.j.mte boulliagna, w acceglio, piemonte (italie): anisien moyen 1968 favoporella annulata n. gen. n. sp.sokaë, pl. i, fig. 1-4; pl. ii, fig. 1-4; pl. iii, fig. 1-5; pl. iv, fig. 1-5.sw poëitelj, mala vodica, velebit mt (croatie): anisien supérieur ladinien inférieur.holotype: pl. ii, fig. 1, lame mince n° go-3201/34, collection b. sokaë, institut za geoloπka istraæivanja [i n s t i tute of geology ], zagreb (croatie) 1971 diplopora annulatissima .uroπeviê, pl. v, fig. 1-3.vrelo, n niπ, e serbie (yougoslavie): anisien, illyrien; pl. vi, fig. 1-4.vrelo, n niπ, e serbie (yougoslavie): anisien supérieur ladinien fig. 14 favoporella annulata (soka», 1968, pl. i, fig. 1), x9. fig. 15 favoporella annulata (soka», 1968, pl. iii, fig. 3), x11. 87granier & grgasoviê: les algues dasycladales du permien et du trias... 1972c diplopora annulatissima .ott, fig. 2, n° 1-10.martinswand, innsbruck, tirol et/ou reiteralm, hundshornscholle (autriche): anisien 1975 (?) diplopora cf. annulatissima .christodoulou & tsaïla-monopolis, pl. x, fig. 1.rema yannoulas torrent, thriassion plain, erythrai (grèce): trias moyen 1976 diplopora annulatissima .hanáëek, pl. vii, fig. 2 pars; pl. ix, fig. 1.slatinka nad bebravou, stráæovské vrchy, e trencín (slovaquie): ladinien (wettersteinkalk) 1977 diplopora annulatissima .salaj, pl. i, fig. 6 pars.silická brezová, slovenský kras (slovaquie): anisien supérieur (zone à pilammina densa ) 1977 diplopora .wray, fig. 107, extrait de herak (1965: pl. v, fig. 3) 1977 diplopora annulatissima .zorn, fig. 1.a.alpes (?): trias moyen 1978 diplopora annulatissima .anelkoviê, pl. lxix, fig. 5, extrait de herak (1963: fig. 38) 1978 diplopora annulatissima .ramovπ, fig. 6.3.n mojstrana, w jesenice (slovénie): trias moyen 1979 diplopora annulatissima .kotański, pl. 79, fig. 1.c, 2.d-e & 7-9.tatry (pologne): anisien, illyrien 1980 diplopora annulatissima .dragastan, pl. v, fig. 3.ruget, pǎdurea craiului, apuseni mts, bihor (roumanie): anisien supérieur 1981 diplopora .ercegovac, extrait de herak (1965: pl. v, fig. 3) 1981 diplopora annulatissima .gaetani et al., fig. 4.contrin, marmolada, trentino alto adige (italie): anisien supérieur (contrin fm) 1982 diplopora annulatissima .bystrický, pl. 2, fig. 1 pars; pl. 4, fig. 3 pars.slatinka nad bebravou ©ípkov, stráæovské vrchy, e trencín (slovaquie): anisien-ladinien 1982 favoporella annulata .bystrický, pl. 4, fig. 4.slatinka nad bebravou ©ípkov, stráæovské vrchy, e trencín (slovaquie): anisien, ou d’après bystrický (1986): anisien, pelsonien-illyrien inférieur (p h y s o porella pauciforata oligoporella pilosa assemblage zone) 1982 (?) favoporella annulata .bystrický, pl. 4, fig. 1.slatinka nad bebravou ©ípkov, stráæovské vrchy, e trencín (slovaquie): anisien 1982 (?) diplopora cf. d. annulatissima .e. flügel & mörtl, fig. 3-5.forage k, s edling-e kühnsdorf, völkermarkt, kärnten (autriche): anisien-ladinien inférieur 1983 diplopora annulatissima .fois & jadoul, pl. 1, fig. b.punta lonas, n pontebba / pontafel, friuli venezia giulia (italie): anisien, illyrien (aviasianus zone, calcari nodulari superiori) 1986 diplopora annulatissima .bystrický, pl. iii, fig. 8.domica keëovo, se pleπivec, slovenský kras (slovaquie): anisien-ladinien, illyrien-fassanien; pl. iii, fig. 9, extrait de bystrický (1964: xxv, fig. 1) 1986 favoporella annulata .bystrický, pl. iii, fig. 6.kamenec, s dlhá ves, se pleπivec, slovenský k r a s (slovaquie): anisien, pelsonien-illyrien inférieur (physoporella pauciforata oligoporella pilosa assemblage zone); pl. iii, fig. 12, extrait de bystrický (1982: pl. 4, fig. 4) 1986 diplopora annulatissima .e. flügel, pl. 4, fig. 8.nw riepl, eisenkappel-globasnitz, kärnten (autriche): anisien supérieur 1986 diplopora annulatissima .kotański, pl. ciii, fig. 1.c, 2.d-e & 7-9, extrait de kotański (1979: pl. 79, fig. 1.c, 2.d-e & 7-9); pl. cv, fig. 8, extrait de pia (1931: pl. xxi, fig. 1); pl. cv, fig. 9, extrait de pia (1931: pl. xxi, fig. 2); pl. cv, fig. 10-13.forage z ° arki letnisko 11-z, w z ° arki letnisko, ene kozieglowy, haute silésie (pologne): anisien, illyrien 1986 diplopora annulatissima .senowbari-daryan & abate, pl. 5, fig. 5.n palermo, sicile (italie): anisienladinien 1986 diploporen.senowbari-daryan & abate, pl. 12, fig. 1.n palermo, sicile (italie): anisien-ladinien 1986 non diplopora annulatissima .sudar, pl. xxv, fig. 4.han bulog, sarajevo (bosnie-herzégovine): ladinien (wettersteinkalk) 1987 diplopora annulatissima .braga & martin, pl. i, fig. 1.sierra de baza, gor baza, granada (espagne): anisien-ladinien 1989 favoporella annulata .buëek, pl. i, fig. 8.w zárub, malé karpaty (slovaquie): anisien, pelsonienillyrien inférieur (steinalmkalk) 1993 diplopora annulatissima .senowbari-daryan et al., pl. 55, fig. 1, 6 & 8.flatschkofel, e s. vigilio di marebbe / st. vigil, s valdáora / olang, trentino alto adige (italie): anisien (richthofen fm); pl. 56, fig. 14.valdáora / olang, pusteria / pustertal, trentino alto adige (italie): anisien supérieur 88 geologia croatica 53/1 1997 diplopora annulatissima .pugliese, pl. 1, fig. 1-5.mte toff, n tione di trento, gruppo di brenta, trentino alto adige (italie): ladinien *kantia philosophi pia 1912, emend. güvenç 1979 [= diplopora philosophi (pia 1912) 1920 ] 1912 kantia philosophi n. sp.pia, pl. vi(v), fig. 17-21.lonaswipfel, mte corona / kronalpe, n pontebba / pontafel, friuli venezia giulia (italie): trias moyen.types: pl. vi(v), fig. 17-18, lame mince n° xiv/1; pl. vi(v), fig. 19, lame mince n° xiv/2; pl. vi(v), fig. 20-21, lame mince n° xiv/3, collec tion j. von pia, naturhistorisches museum, wien (autriche) 1919 kantia (?) brunoi n. sp.baretti, fig. 7 & 7.a-b.garavagna, mondovi, piemonte (italie): trias.types: fig. 7 & 7.a-b 1919 kantia philosophi var. g r a c i l i s n. var.baretti, fig. 3 & 3.a.mte calvario, mondovi, piemonte (italie): trias.types: fig. 3 & 3.a 1919 kantia philosophi .baretti, fig. 3 & 3.a.villanova mondovi-mte calvario, mondovi, piemonte (italie): trias 1919 (?) kantia philosophi.négris, pl. xxix, fig. 1-2.katsimidi, parnassós mts (grèce): trias 1920 non diplopora philosophi n. comb. [= diplopora exuberans var. exuberans, nom. nud.].pia, pl. v, fig. 9-11 1962b non diplopora cf. philosophi [= ? diplopora exuberans var. exuberans, nom. nud.].michard, pl. viii, fig. 1-2; pl. ix, fig. 1 & 2 pars 1964 (?) diplopora cf. philosophi.bystrický, pl. xxx, fig. 7.zádielska planina, s varhút, slovenský kras (slovaquie): ladinien inférieur (wettersteinkalk) 1965a non diplopora philosophi var. philosophi [= diplopora exuberans var. trumpyi, nom. nud.].zanin-buri, pl. 58-59 1969 diplopora philosophi .diaconu & dragastan, pl. viii, fig. 6-7.dealul glimeia, apuseni mts (roumanie): anisien supérieur 1971 non diplopora philosophi philosophi [= diplopora exuberans var. exuberans, nom. nud.].zorn, pl. 4, fig. 3; pl. 17, fig. 9 1979 kantia philosophi emend.güvenç, p. 631, non figurée 1980 diplopora philosophi .dragastan, pl. v, fig. 1, extrait de diaconu & dragastan (1969: pl viii, fig. 6); pl. v, fig. 2.glimeia, ruget, pǎdurea craiului, apuseni mts, bihor (roumanie): anisien supérieur 1981 diplopora philosophi .dragastan, pl. 9, fig. 1, extrait de diaconu & dragastan (1969: pl viii, fig. 6) kantia philosophi var . gracilis baretti 1919 [variété superflue; cf. kantia philosophi pia 1912, emend. güvenç 1979 ] kantia praecursor (pia 1920) güvenç 1979 [= diplopora praecursor pia 1920, emend. hurka & schmid 1971 ] 1920 diplopora praecursor n. sp.pia, pl. v, fig. 28.sandkogel / schlegelberg, vorderstaff, schwarzenbach an der pielach, niederösterreich (autriche): anisien.type: pl. v, fig. 28, collection j. von pia, naturhistorisches museum, wien (autriche) 1944 diplopora annulata .johnson, pl. 302, fig. 9, extrait de pia (1920: pl. v, fig. 28) 1971 diplopora praecursor emend.hurka & schmid, fig. 1.a-k, 2.a-h & 3.a-f; pl. 1, fig. 1-11; pl. 2, fig. 1-9.n mte serla / sarlkofel se putzalm, se villabassa / niederdorf, pusteria / pustertal, trentino alto adige (italie): anisien (pragser dolomiten) 1979 kantia praecursor n. comb.güvenç, p. 631, non figurée kantia ? subtilis (pia 1935) güvenç 1979 [= diplopora subtilis pia 1935 ] kantia ? subtilis var. calicina (pia 1935) güvenç 1979 [= diplopora subtilis var. calicina pia 1935 ] 1935a diplopora subtilis var. calicina n. var.pia, pl. v, fig. 4.w trebeviê, s sarajevo (bosnie-herzégovine): anisien, hydaspien supérieur pelsonien; pl. v, fig. 2-3 & 5.gradiπte, e sarajevo (bosnie-herzé89granier & grgasoviê: les algues dasycladales du permien et du trias... govine): anisien, pelsonien; pl. v, fig. 6-7.n haliluêi, e sarajevo (bosnie-herzégovine): anisien, pels o n i e n.type: pl. v, fig. 2, lame mince n° 568b, collection j. von pia, naturhistorisches museum, wien (autriche) 1994 diplopora subtilis var. calicina .bucur et al., pl. 13, fig. 1 pars.sasca zone, caraş-severin (roumanie): anisien, pelsonien-illyrien inférieur (sasca fm, valea susara limestone member) kantia ? subtilis var . dissocladelloidea (pia 1935) güvenç 1979 [= diplopora subtilis var . dissocladelloidea pia 1935 ] 1935a d i p l o p o r a s u b t i l i s var. dissocladelloidea n. var.pia, pl. iv, fig. 4.s mokranjska miljacka, e sarajevo (bosnie-herzégovine): anisien; pl. iv, fig. 5-6.n haliluêi, e sarajevo (bosnie-herzégovine): anisien, p e l s o n i e n.type: pl. iv, fig. 4, lame mince n° 569a (1), collection j. von pia, naturhistorisches museum, wien (autriche) 1994 d i p l o p o r a s u b t i l i s var. d i s s o c l a d e l l o i d e a .bucur et al., pl. 13, fig. 13-15.sasca zone, caraşs e v e r i n (roumanie): anisien, pelsonien-illyrien inférieur (sasca fm, valea susara limestone member) kantia ? subtilis var . graeca (herak 1967) güvenç 1979 [= diplopora subtilis var . graeca herak 1967 ] 1967a diplopora subtilis var. graeca n. var.herak, pl. 10, fig. 1-8.ligaridi, khíos / chios (grèce): anisien.holotype: pl. 10, fig. 1, lame mince n° 342, collection k.w. tietze, geologisch-paläontologischen institut der universität marburg (allemagne) kantia ? subtilis var . subtilis (pia ex bystricky´ 1964) güvenç 1979 [= diplopora subtilis var . subtilis pia ex bystricky´ 1964; = diplopora subtilis forma typica pia 1935, nom. nud. ] 1 9 3 5 a (nom. nud.) diplopora subtilis n. sp. (forma typica).pia, pl. v, fig. 8-9 & 11-12.n haliluêi, e sarajevo (bosnie-herzégovine): anisien, pelsonien; pl. v, fig. 10 & 13.s mokranjska miljacka, e sarajevo (bosnie-herzégovine): anisien.type: pl. v, fig. 9, lame mince n° 577a (23), collection j. von pia, naturhistorisches museum, wien (autriche) 1964 diplopora subtilis var. subtilis n. var.bystrický, pl. xxiii, fig. 8.silická planina, slovenský kras (slovaquie): anisien, illyrien inférieur; pl. xxiv, fig. 1.pleπivecká planina, slovenský kras (slovaquie): anisien, pelsonien; pl. xxiv, fig. 2.zakázané, silická planina, slovenský kras (slovaquie): anisien supérieur, ou d’après bystrický (1986): anisien, pelsonien-illyrien inférieur (physoporella pauciforata oligoporella pilosa assemblage zone) 1965 diplopora subtilis .herak, pl. xi, fig. 2-3.skubrov vrh, jezersko (slovénie): anisien 1966 diplopora subtilis var. s u b t i l i s.bystrický, pl. viii, fig. 1-2.ponická lehôtka poniky oravce postredná môlëa, e banská bystrica (slovaquie): anisien, pelsonien (steinalmkalk) 1970 diplopora subtilis subtilis .patrulius, pl. iv, fig. 3-4.valea lupşa, perşani mts, braşov (roumanie): anisien, pelsonien-illyrien inférieur 1975 diplopora subtilis subtilis .baltres, pl. ii, fig. 4.lacul roşu, e carpathes (roumanie): anisien supérieur 1978 diplopora subtilis .anelkoviê, pl. lxv, fig. 3, extrait de herak (1965: pl. xi, fig. 2) 1979 kantia ? subtilis n. comb.güvenç, p. 631, non figurée 1986 diplopora subtilis var. subtilis.bystrický, pl. iii, fig. 3, extrait de bystrický (1964: pl. xxiv, fig. 2) kantia uniserialis (pia 1920) güvenç 1979 [= diplopora uniserialis (forma vesiculifera) pia 1920 ] 1920 diplopora uniserialis n. sp. (forma vesiculifera).pia, pl. v, fig. 1, 4-5 & 7.rothorn, diemtigtal, bern (suisse): trias moyen, ? anisien; pl. v, fig. 8.chable-croix, trévenensaz-masse, muraz vionnaz, valais (suisse): trias moyen, ? anisien.types: pl. v, fig. 1, 4-5 & 7, lames minces n° ?, collection j. von pia, naturhistorisches museum, wien (autriche) 1933 diplopora annulata var. briançonnensis n. var. forma vesiculifera.schneegans, pl. i, fig. 1.w aiguille rouge, névache, hautes-alpes (france): trias moyen; pl. ii, fig. 3-4.rocher de la tête noire, ne val des prés (france): trias moyen.types: pl. i, fig. 1-6; pl. ii, fig. 1-8 & 12-14 90 geologia croatica 53/1 1933 (?) diplopora annulata var. briançonnensis n. var.schneegans, pl. i, fig. 4-5; pl. ii, fig. 13-14.rocher de la tête noire, ne val des prés (france): trias moyen; pl. i, fig. 6.col de l’izoard, arvieux, hautesalpes (france): trias moyen; pl. ii, fig. 12.grand galibier, savoie (france): trias (galet de la brèche triasique) 1958 diplopora cf. brianconnensis = diplopora uniserialis .ellenberger, pl. 7, fig. 21-22 & 24; pl. 22, fig. 4.paroi de la porteille, forêt de sollières, montfroid, vanoise, savoie (france): ladinien (en éboulis); pl. 7, fig. 23.la petite turra, mont-cenis, vanoise, savoie (france): ladinien 1958 diplopora uniserialis .genge, pl. viii, fig. 5-6.spillgerten, ne grat, bern (suisse): ladinien (gebänderte kalk) 1961 diplopora uniserialis (type vésiculé) [s i c].botteron, pl. v, fig. 4.arête de la pierre du moëllé, mont d’or, vaud (suisse): ladinien 1968 (?) diplopora uniseriatis [s i c] diplopora uniserialis .mégard-galli, fig. 7.d.mte boulliagna, w acceglio, piemonte (italie): ladinien inférieur 1969 (nom. nud.) diplopora uniserialis var. brianconensis n. comb. [sic].bloch in bloch & lefevre, p. 1167, non figurée.type non désigné 1979 kantia uniserialis n. comb.güvenç, p. 631, non figurée 1979 diplopora uniserialis .kotański, pl. 80, fig. 6-9.tatry (pologne): ladinien inférieur 1986 diplopora uniserialis .kotański, pl. civ, fig. 6-9, extrait de kotański (1979: pl. 80, fig. 6-9) 1994 (?) k a n t i a sp. cf. k a n t i a u n i s e r i a l i s .bucur et al., pl. 13, fig. 8.sasca zone, caraş-severin (roumanie): anisien, pelsonien-illyrien inférieur (sasca fm, valea susara limestone member) kochanskyella milanovi∆ 1974 *kochanskyella tulipa milanovi∆ 1974 1 9 3 7 (?) (nom. nud.) a t r a c t y l i o p s i s n. sp.pia, pl. 10(94), fig. 6.schloss thurn, val badia / gadertal, trentino alto adige (italie): permien supérieur (bellerophon limestone) 1963 (?) atractyliopsis sp.johnson, pl. 50, fig. 7, extrait de pia (1937: pl. 10(94), fig. 6) 1974 kochanskyella tulipa n. gen. n. sp.milanoviê, pl. i, fig. 1-4; pl. ii, fig. 1-5; pl. iii, fig. 1-9; pl. iv, fig. 16; pl. v, fig. 1-5.brezik, okiê, medak & meuvode, se gospiê, velebit mt (croatie): artinskien supérieur kazanien inférieur.holotype: pl. i, fig. 1, lame mince n° br. 8b/5, collection m. milanoviê, institut za geoloπka istraæivanja [institute of geology ], zagreb (croatie) 1980 kochanskyella tulipa.vachard, pl. 23, fig. 11.tezak khwaja bahadur, tezak (afghanistan): kubergandien 1980 kochanskyella.vachard, pl. 23, fig. 12 pars.tezak khwaja bahadur, tezak (afghanistan): murghabien supérieur 1981 kochanskyella tulipa.vachard in vachard & montenat, pl. 5, fig. 10.khwaja bahadur, tezak (afghanistan): murghabien inférieur; pl. 5, fig. 15, extrait de vachard (1980: pl. 23, fig. 11) 1988 (?) atractyliopsis.deloffre, pl. 4, fig. 17, extrait de pia (1937: pl. 10(94), fig. 6) 1990 (?) teutloporella ? sp.e. flügel, pl. 3, fig. 1.e balya, wnw balikesir (turquie): bolorien (zone à misel lina) kungurella chuvashov in chuvashov et anfimov 1988 *kungurella ornementata chuvashov in chuvashov et anfimov 1988 1988 kungurella ornementata n. gen. n. sp.chuvashov in chuvashov & anfimov, pl. xxviii, fig. 1-4.rivière sylva, w yekaterinburg, w oural (fédération de russie): kungurien.holotype: pl. xxviii, fig. 1, lame mince n° π 210-44, collection b.i. chuvashov, unt ai sssr [institute of geology and geochemistry of urals, section of russian academy of sciences ], yekaterinburg (fédération de russie) 91granier & grgasoviê: les algues dasycladales du permien et du trias... lacrymorphus elliott 1958 *lacrymorphus perplexus elliott 1958 1958 lacrymorphus perplexus n. gen. n. sp.elliott, pl. 3, fig. 10.ora, mosul liwa, n irak (irak): trias s u p é r i e u r.holotype: pl. 3, fig. 10, lame mince n° wi. 8618; paratype (non figuré): lame mince n° wl. 8618, collection g.f. elliott, british museum (natural history), london (royaume-uni) likanella milanovi∆ in granier et deloffre 1995, non 1966 likanella lata endo ex granier et deloffre 1995 1969 (nom. nud.) likanella lata n. sp.endo, pl. xxxvii, fig. 4-10; pl. xxxviii, fig. 5-7; pl. xli, fig. 4.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina zone à neoschwagerina simplex / partie inférieure).holotype: pl. xxxvii, fig. 4, lame mince n° gk.d 13002, kyūshū university, fukuoka (japon) 1995 likanella lata .granier & deloffre, p. 57, non figurée.validation de l’espèce likanella longispinosa endo ex granier et deloffre 1995 1968b (nom. nud.) salopekiella cf. velebitana.endo, pl. i, fig. 5.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien 1 9 6 9 (nom. nud.) likanella longispinosa n. sp.endo, pl. xxxviii, fig. 1-4; pl. xlii, fig. 7-8.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à c a n c e l l i n a zone à neoschwagerina simplex / partie inférieure).holotype: pl. xxxviii, fig. 1, lame mince n° gk.d 13079, kyūshū university, fukuoka (japon) 1995 likanella longispinosa.granier & deloffre, p. 57, non figurée.validation de l’espèce likanella minima milanovi∆ 1986, nom. nud. 1 9 8 6 (nom. nud.) likanella minima n. sp.milanoviê, pl. iii, fig. 1-4.ciganski jarak, n mrzle vodice, gorski kotar (croatie): permien inférieur (rattendorfer schichten / partie supérieure).absence de diagnose et type non désigné: pl. iii, fig. 1-4, collection m. milanoviê, institut za geoloπka istraæivanja, zagreb (croatie) likanella porosa endo 1968, nom. nud. 1 9 6 8 b (nom. nud.) likanella porosa n. sp.endo, pl. i, fig. 2-3.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (zone à c a n c e l l i n a ).type non désigné: pl. i, fig. 2, lame mince n° 13234; pl. i, fig. 3, lame mince n° 13233, department of geology, kyūshū university, fukuoka (japon) *likanella spinosa milanovi∆ in granier et deloffre 1995, non 1966 1 9 6 5 (nom. nud.) johnsonia spinosa n. gen. n. sp.kordé, pl. liv, fig. 3.a-b.dorasham 1, dzhul’fa, nakhichevan’ (azerbaïdjan): guadalupien; pl. liv, fig. 4 & 7.dorasham 2, dzhul’fa, nakhichevan’ (azerbaïdjan): guadalupien.“golotip” (syntypes): pl. liv, fig. 3.a-b, lame mince n° 2307/8, collec tion k.b. kordé, moscou (fédération de russie) 1965b (nom. nud.) likanella spinosa .milanoviê, fig. 2.b-d.velebit mt (croatie): permien “moyen”-”supérieur” 1 9 6 6 a (nom. nud.) l i k a n e l l a s p i n o s a n. gen. n. sp.milanoviê, pl. i, fig. 1 [= pl. iv, fig. 5], extrait de milanoviê (1965b: fig. 2.d); pl. i, fig. 2; pl. i, fig. 3 [= pl. ii, fig. 5], extrait de milanoviê (1965b: fig. 2.c); pl. i, fig. 4 [= pl. iv, fig. 2]; pl. i, fig. 5 [= pl. ii, fig. 7], extrait de milanoviê (1965b: fig. 2.b); pl. i, fig. 6 [= pl. ii, fig. 2]; pl. i, fig. 7 [= pl. iv, fig. 7]; pl. i, fig. 8 [= pl. ii, fig. 4]; pl. ii, fig. 1-7; pl. iii, fig. 1-7; pl. iv, fig. 1-8.velebit mt (croatie): permien “moyen”-”supérieur”.syntypes: pl. i, fig. 5 [= pl. ii, fig. 7] & pl. ii, fig. 1, lame mince n° br.-8b/3; pl. i, fig. 6 [= pl. ii, fig. 2 ], lame mince n° br.-8b/2; pl. i, fig. 8 [= pl. ii, fig. 4 ] & pl. ii, fig. 3, lame mince n° u330/4; pl. i, fig. 3 [= pl. ii, fig. 5 ], lame mince n° 8b/1; pl. ii, fig. 6, lame mince n° br.-8b/7, collection m. milanoviê, institut za geoloπka istraæi vanja [institute of geology ], zagreb (croatie) 92 geologia croatica 53/1 1969 (nom. nud.) likanella spinosa.radoiëiê, pl. ii, fig. 7, extrait de milanoviê (1966a: pl. iv, fig. 4) 1972 non (nom. nud.) likanella ? cf. l. spinosa [= connexia carniapulchra ].homann, pl. 6, fig. 44 1 9 7 3 (nom. nud.) likanella spinosa.kochansky-devidé et al., pl. 2, fig. 9-10.medvodje, ne træië (slovénie): permien inférieur (trogkofelkalk) 1 9 7 4 (?) (nom. nud.) likanella cf. s p i n o s a.mirkoviê, pl. x, fig. 1.sisica, rivière lim, e monténégro (yougoslavie): permien “moyen” 1995 likanella spinosa.milanoviê in granier & deloffre, p. 57, non figurée.typification et validation de l’espèce; lectotype: pl. ii, fig. 1 in milanoviê (1966a), lame mince n° br.-8b/3, collection m. milanoviê, institut za geoloπka istraæivanja [institute of geology ], zagreb (croatie) macroporella pia 1912, emend. bassoullet et al. 1978 macroporella affinis endo 1969 1969 macroporella affinis n. sp.endo, pl. xi, fig. 4-9.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina zone à neoschwagerina simplex / partie inférieure).holotype: pl. xi, fig. 4, lame mince n° gk.d 13973 ou 13979 (?), kyūshū university, fukuoka (japon) 1991a macroporella affinis .wu, pl. iv, fig. 5.xiangbo, longlin county, guangxi (chine populaire): guadalupien, ‘maokouan’ 1991b macroporella affinis .wu, pl. 22, fig. 5, extrait de wu (1991a: pl. iv, fig. 5) macroporella aganoensis ishijima et al. 1971 1971 macroporella aganoensis n. sp.ishijima et al., pl. 8, fig. 3; pl. 9, fig. 3.sakaishimachibun, aganomura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur”.holotype: pl. 9, fig. 3, spécimen n° nsmp1-18073b, national science museum, tokyo (japon) macroporella akiyoshensis endo 1961, nom. nud. 1961c (nom. nud.) macroporella akiyoshensis n. sp.endo, absence de diagnose et de figuration macroporella alpina pia 1912 1912 m a c r o p o r e l l a a l p i n a n. sp.pia, pl. ii(i), fig. 13-15.fuchsriegel, s unter-steinrott-bauer, schwarzenbach an der pielach, niederösterreich (autriche): trias moyen (reiflinger kalk).types: pl. ii(i), fig. 13-14, lame mince n° lvii/1; pl. ii(i), fig. 15, lame mince n° lvii/2, collection j. von pia, naturhistorisches museum, wien (autriche) 1915 (?) macroporella alpina .négris, pl. xvi, fig. ß.stephanion, parnassós mts (grèce): “carbonifère” 1935a m a c r o p o r e l l a a l p i n a .pia, pl. i, fig. 1.ograda, bosansko grahovo (bosnie-herzégovine): anisien, ? hydaspien; pl. i, fig. 2-3.ograda, bosansko grahovo (bosnie-herzégovine): anisien; pl. i, fig. 4.nw blizanac, trebeviê, s sarajevo (bosnie-herzégovine): anisien, pelsonien; pl. i, fig. 5; pl. ii, fig. 1-2.n haliluêi, e sarajevo (bosnie-herzégovine): anisien, pelsonien 1959 macroporella alpina .pantiê, pl. vi, fig. 1-3 & 4.a-b.zekova glava, bjelasica mt, monténégro (yougoslavie): anisien, pelsonien 1961 (?) macroporella sp. cf. alpina .botteron, pl. v, fig. 3.mont d’or, vaud (suisse): “virglorien” (anisien) 1961 (?) macroporella sp.botteron, pl. vii, fig. 2.mont d’or, vaud (suisse): “virglorien” (anisien) 1964 m a c r o p o r e l l a a l p i n a .bystrický, pl. v, fig. 1.silická brezová, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur; pl. v, fig. 2 & 6.roækov, e pleπivec, silická planina, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur; pl. v, fig. 3.zakázané, silická planina, slovenský k r a s (slovaquie): anisien, ? illyrien inférieur; pl. v, fig. 7.s dolný vrch, aggteleki-karszt (hongrie): anisien, pelsonien-illyrien inférieur; pl. vi, fig. 1.szárosz-szoba, silická planina, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur 1964 (?) ? m a c r o p o r e l l a a l p i n a .bystrický, pl. v, fig. 4 & 5.silická brezová, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur 1965 (?) m a c r o p o r e l l a cf. a l p i n a .assereto et al., pl. 77, fig. 1-3; pl. 81, fig. 1.w castelfranco, val gola / val camónica, ne bergamo, lombardia (italie): anisien (calcare di camorelli) 93granier & grgasoviê: les algues dasycladales du permien et du trias... 1965 macroporella alpina .herak, pl. ix, fig. 1.a.plavno, pleπivica, nw knin (croatie): anisien; pl. ix, fig. 2.deralo, bosansko grahovo (bosnie-herzégovine): anisien 1966 macroporella alpina .bystrický, pl. v, fig. 1.ponická lehôtka poniky oravce postredná môlëa, e banská bystrica (slovaquie): anisien, pelsonien (steinalmkalk) 1967b m a c r o p o r e l l a a l p i n a .herak, pl. 2, fig. 5; pl. 3, fig. 5-6.loßeck, gosaukamm, dachsteingruppe, oberösterreich (autriche): anisien (massenkalk) 1967 m a c r o p o r e l l a a l p i n a .hurka, pl. 7, fig. 5.e bagni di piandimáia / bad maistatt, villabassa / niederdorf, pusteria / pustertal, trentino alto adige (italie): anisien, hydaspien supérieur (prasgser dolomiten) 1967 m a c r o p o r e l l a a l p i n a .pantiê, pl. ii, fig. 1.pepeljevaëke stene, tara mt, w serbie (yougoslavie): anisien 1969 non m a c r o p o r e l l a a l p i n a .endo, pl. vi, fig. 3-7.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina ) 1969 non macroporella alpina [= poncetella helvetica].kobel, photo 12 1970 m a c r o p o r e l l a a l p i n a .pantiê, pl. viii, fig. 1-2.ædrelo, e serbie (yougoslavie): anisien, pelsonien (“zone avec rhynchonella decurtata”) 1970 m a c r o p o r e l l a a l p i n a .papp & turnovsky, pl. 9 pars; pl. 10 pars.sw gosaukamm, dachsteingruppe, salzburg (autriche): anisien (massenkalk) 1971 m a c r o p o r e l l a a l p i n a .zorn, pl. 17, fig. 5.fornace, n campione d’italia, s lugano, ticino (suisse): anisien supérieur ladinien inférieur (mittlerer salvatoredolomit, gervillienhorizont) 1972 m a c r o p o r e l l a a l p i n a .bleahu et al., pl. v, fig. 1.vaşcǎu plateau, apuseni mts, bihor (roumanie): anisien moyen-supérieur 1972b macroporella alpina .pantiê, pl. iii, fig. 1.senokoπe, poæega, w serbie (yougoslavie): anisien 1973 m a c r o p o r e l l a a l p i n a .popa & dragastan, pl. xv, fig. 60 pars.e lorǎu, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à dadocrinus communis); pl. xvi, fig. 62 pars.w vǎii iadului, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à dadocrinus communis) 1975 macroporella alpina .baltres, pl. ii, fig. 6-7.lacul roşu, e carpathes (roumanie): anisien supérieur 1975 macroporella alpina .dragastan & grǎdinaru, pl. ii, fig. 10-13; pl. iii, fig. 14 & 20 pars; pl. vi pars.s dunavát, tulcea (roumanie): anisien, pelsonien-illyrien inférieur 1975 macroporella alpina .pantiê-prodanoviê, pl. xxv, fig. 1.beëiêi, e budva, monténégro (yougoslavie): anisien 1977 macroporella alpina .gaździcki & smit, pl. 2, fig. 5.mogota bukit kalong, s kodiang, kedah, nw malaysia (malaisie): anisien-ladinien (kodiang limestone fm) 1977 non m a c r o p o r e l l a aff. a l p i n a .miπík et al. (bystrický), pl. i, fig. 2.nosice, vallée moyenne du váh, w carpathes (slovaquie): anisien (galet de steinalmkalk dans un conglomérat d’âge albien) 1978 macroporella alpina .anelkoviê, pl. lxv, fig. 7, extrait de herak (1965: pl. ix, fig. 1.a) 1981 non macroporella alpina .nakamura, pl. 9, fig. 1-2; pl. 10, fig. 2-3.ishiyama, o _ n o c hō tanigumi-mura, gifu-ken, honshū (japon): permien (ishiyama limestone) 1982 macroporella alpina .farabegoli & levanti, pl. 6, fig. 2 pars.mte tuglia-mte pleros, sappada, véneto (italie): anisien, illyrien supérieur 1982 macroporella alpina .veliê & sokaë, pl. iii, fig. 1 & 2 pars.poloj, w kordun, sw karlovac (croatie): anisien 1986 m a c r o p o r e l l a a l p i n a .bystrický, pl. i, fig. 5-6.silická brezová, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur (physoporella pauciforata oligoporella pilosa assemblage zone) 1986 m a c r o p o r e l l a a l p i n a .sudar, pl. xxv, fig. 1-2.han bulog, sarajevo (bosnie-herzégovine): anisien, pelsonien (dedoviêi carbonates) 1986 (?) m a c r o p o r e l l a cf. a l p i n a .sudar, pl. xxviii, fig. 3.han bulog, sarajevo (bosnie-herzégovine): anisien, pelsonien (dedoviêi carbonates) 1989 macroporella alpina .buëek, pl. i, fig. 6.n havranica, malé karpaty (slovaquie): anisien, pelsonienillyrien inférieur (steinalmkalk) 1989 m a c r o p o r e l l a a l p i n a .gaetani & gorza, pl. 10, fig. 7.crinale, lóvere, val camónica, ne bergamo, lombardia (italie): anisien (calcare di camorelli) 94 geologia croatica 53/1 1993 (?) m a c r o p o r e l l a a l p i n a (sic, dans le texte, devient d i p l o p o r a ? cf. d i p l o p o r a s e r i a l i s dans la légende des figures).senowbari-daryan et al., pl. 56, fig. 15 & 17.valdáora / olang, pusteria / pustertal, trentino alto adige (italie): anisien supérieur 1993 (?) m a c r o p o r e l l a cf. m a c r o p o r e l l a a l p i n a .senowbari-daryan et al., pl. 57, fig. 3 (non 2).piz da perez, valdáora / olang, pusteria / pustertal, trentino alto adige (italie): anisien, pelsonien supérieur (fm dei calcari de recoaro) 1994 (?) m a c r o p o r e l l a sp. cf. m a c r o p o r e l l a a l p i n a .bucur et al., pl. 10, fig. 6.sasca zone, caraşs e v e r i n (roumanie): anisien, pelsonien-illyrien inférieur (sasca fm, valea susara limestone member) 1994 macroporella alpina .e. flügel et al., pl. 1, fig. 4-6; pl. 6, fig. 2.bled (slovénie): anisien, ? ‘aegean’ pelsonien 1995 non m a c r o p o r e l l a gr. a l p i n a .pantiê-prodanoviê, pl. iii, fig. 9.paleæ, w srebrenica (bosnie-herzégovine): ladinien macroporella apachena johnson 1951 1951 macroporella apachena n. sp.johnson, pl. 8, fig. 1-4.apache mts, texas (états-unis d’amérique): guadalupien (probablement ? capitanien) .types: pl. 8, fig. 1-4, lame mince n° 1103, collection h.j. johnson, colorado school of mines, golden, colorado (états-unis d’amérique) 1956 (?) macroporella apachena .jones, fig. 4.5.b; d’après l’auteur, cette figure serait extraite de johnson (1951) 1961 m a c r o p o r e l l a .johnson, pl. 54, fig. 1-2, extrait de johnson (1951: pl. 8, fig. 1-2) [“from carozzi”: “jurassic, switzerland”!] 1963 macroporella apachena .johnson, pl. 59, fig. 1-4, extrait de johnson (1951: pl. 8, fig. 1-4) 1965 macroporella apachena .kordé, pl. lvi, fig. 8.chanakhchi (arménie): guadalupien 1966 macroporella apachena .johnson & danner, pl. 55, fig. 10.se mt bowman, e jesmond, british columbia (états-unis d’amérique): permien “supérieur” (cache creek group, marble canyon fm); pl. 55, fig. 11.nw porcupine creek, e jesmond, british columbia (états-unis d’amérique): permien “supérieur” (cache creek group, marble canyon fm) 1977 macroporella apachena .vachard in h. termier et al., pl. 2, fig. 1.djebel tebaga (tunisie): murghabien (dolomies inférieures et marnes du chabet n guer) 1978a macroporella apachena .mamet & roux, pl. 1, fig. 10, extrait de h. termier et al. (1977: pl. 2, fig. 1) 1980 macroporella apachena .e. flügel & flügel-kahler, pl. 4, fig. 7.nw mte covolo / seikofel, ese sesto / sexten, trentino alto adige (italie): permien inférieur (kalkbrekzie) 1990 macroporella apachena .e. flügel, pl. 4, fig. 1 & 3.balya-edremit, sw balya, w balikesir (turquie): murghabien supérieur (zone à neoschwagerina / partie supérieure) 1992 macroporella apachena .vachard et al., pl. iii, fig. 9 pars & 10 pars.n ban na wai, nw thaïlande (thaïlande): murghabien supérieur midien 1993 macroporella apachena .vachard et al., pl. i, fig. 2.s ermióni, argolís (grèce): djulfien (galet dans une “coulée boueuse” kimméridgienne de la fm de potami) macroporella atagoyamensis nakamura et chisaka 1984, nom. nud. 1 9 8 4 (nom. nud.) macroporella atagoyamensis n. sp.nakamura & chisaka, pl. 7, fig. 15-19.mt atagoyama, chôshi-shi, chiba-ken, honshū (japon): permien “supérieur” (takagami conglomerate).syntypes: pl. 7, fig. 15, lame mince n° nsm-pp 7901d; pl. 7, fig. 16, lame mince n° nsm-pp 7908c, national sci ence museum, tokyo (japon) macroporella bellerophontis (rothpletz 1894) pia 1912 [espèce exclue des dasycladales, il s’agit de l’espèce-type du genre gymnocodium pia 1920; = gyroporella bellerophontis rothpletz 1894 ] macroporella beneckei (salomon 1895) pia 1920 [= diplopora beneckei salomon 1895 ] 1895 diplopora beneckei n. sp.salomon, pl. i, fig. 21, 22.a-b & 23-27.marmolada, trentino alto adige véneto (italie): trias ? moyen (wettersteinkalk).types: pl. i, fig. 21, 22.a-b & 23-27, collection w. salomon, münchen (allemagne) 95granier & grgasoviê: les algues dasycladales du permien et du trias... 1915 non macroporella beneckei .négris, pl. xi + fig.ktipás mt, voiotía (grèce): trias 1919 non macroporella beneckei .négris, pl. xxvii, fig. 1.ktipás mt, voiotía (grèce): trias 1920 macroporella beneckei n. comb.pia, pl. i, fig. 24-26.marmolada, trentino alto adige véneto (italie): ladinien 1964 macroporella beneckei .bystrický, pl. vi, fig. 2.w domica, se pleπivec, slovenský kras (slovaquie): ladinien inférieur (wettersteinkalk) 1965 macroporella beneckei .herak, pl. ix, fig. 3; pl. x, fig. 1-4.orlovica, n knin (croatie): ladinien 1966 macroporella beneckei.bystrický, pl. v, fig. 2.ponická lehôtka poniky oravce postredná môlëa, e banská bystrica (slovaquie): ladinien (wettersteinkalk) 1967 macroporella beneckei .pantiê, pl. iv, fig. 3-4.sokolarica, tara mt, w serbie (yougoslavie): ladinien 1969 macroporella beneckei .diaconu & dragastan, pl. v, fig. 1.dealul glimeia, apuseni mts (roumanie): ladinien 1971 macroporella beneckei.zorn, pl. 17, fig. 8.san martino, ticino (suisse): anisien supérieur ladinien inférieur (mittlerer salvatoredolomit, gervillienhorizont) 1973 macroporella beneckei .popa & dragastan, pl. xix, fig. 76 pars.dealul ruget remeţi, w valea boiului, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien-ladinien, illyrien supérieur langobardien 1976 macroporella beneckei .epting et al., fig. 8.c.mte spitz, s recoaro terme, w schio, véneto (italie): anisien-ladinien, illyrien supérieur fassanien (monte spitz limestone) 1978 macroporella beneckei .anelkoviê, pl. lxix, fig. 3, extrait de herak (1965: pl. x, fig. 2) 1980 macroporella beneckei .dragastan, pl. vi, fig. 6, extrait de diaconu & dragastan (1969: pl. v, fig. 1) 1981 macroporella .ercegovac, extrait de herak (1965: pl. x, fig. 2) 1987 macroporella benecki [s i c].braga & martin, pl. i, fig. 3.sierra de baza, gor baza, granada (espagne): anisien-ladinien 1988 macroporella beneckei .pfeiffer, pl. 11, fig. 3.gartnerkofel, s hermagor, kärnten (autriche): ladinien, fassanien (schlerndolomit) 1990 macroporella beneckei .scheuber, pl. 10, fig. 1.mte rove, recoaro terme, w schio, véneto (italie): anisien-ladinien, illyrien fassanien moyen (monte spitz limestone) 1991 (?) macroporella beneckei .bucur, pl. 42, fig. 17.dealul redut sasca montana, resita, caraşs e v e r i n (roumanie): anisien moyen 1994 (?) m a c r o p o r e l l a sp. cf. m a c r o p o r e l l a b e n e c k e i.bucur et al., pl. 10, fig. 7, extrait de bucur (1991: pl. 42, fig. 17).sasca zone, caraş-severin (roumanie): anisien, pelsonien-illyrien inférieur (sasca fm, valea susara limestone member) 1994 macroporella beneckei .e. flügel et al., pl. 1, fig. 1.bled (slovénie): anisien, ? ‘aegean’ pelsonien 1994 (?) m a c r o p o r e l l a cf. b e n e c k e i.e. flügel et al., pl. 1, fig. 2-3.bled (slovénie): anisien, ? ‘aegean’ pelsonien macroporella calicipora pia 1940, nom. nud. 1940a (nom. nud.) macroporella calicipora n. sp.pia, p. 56, non figurée.type non figurée *macroporella dinarica pia 1912 1912 macroporella dinarica n. gen. n. sp.pia, pl. ii(i), fig. 1-6.w lapëiêi, budva, monténégro (yougoslavie): trias moyen.types: pl. ii(i), fig. 1-2 & 5-6, lame mince n° i/3; pl. ii(i), fig. 3-4, lame mince n° i/1, collection j. von pia, naturhistorisches museum, wien (autriche) 1964 (?) macroporella cf. d i n a r i c a .bystrický, pl. vi, fig. 3.e pleπivec, silická planina, slovenský kras (slovaquie): anisien-ladinien macroporella ? helvetica pia 1912 [cf. poncetella helvetica (pia 1912) güvenç 1979 ] macroporella humilis bystrický 1967 [cf. salpingoporella humilis (bystrický 1967) ott 1974 ] 96 geologia croatica 53/1 macroporella infundibula endo 1961 1961b macroporella infundibula n. sp.endo, pl. 7, fig. 5.s minami-toba-ue, nagahama-shi, shiga-ken, hons hū (japon): permien inférieur (samegai fm).holotype: pl. 7, fig. 5, lame mince n° 510605-3, geological survey of japan (japon) 1961c macroporella infundibula .endo, pl. 7, fig. 1.sse tanaiwa, akiyoshi, shuhō-chō, ne mine-shi, yamaguchi-ken, honshū (japon): permien inférieur (akiyoshi limestone group, zone à pseudoschwagerina , sous-zone à pseudofusulina vulgaris ) 1971 macroporella infundibula .ishijima et al., pl. 7, fig. 1-2.sakaishimachibun, agano-mura, hannōs h i , iruma-gun, saitama-ken, honshū (japon): permien “inférieur” macroporella irregularis pia 1924 1924a macroporella irregularis n. sp.pia, pl. i, fig. 9.wai tina, bara bai, nw buru (indonésie): norien; pl. i, fig. 10-11.s tifu, sw buru (indonésie): norien .types: pl. i, fig. 9, lame mince n° ?; pl. i, fig. 1011, lame mince n° ?, collection j. von pia, naturhistorisches museum, wien (autriche) macroporella kantoensis ishijima et al. 1971 1971 macroporella kantoensis n. sp.ishijima et al., pl. 7, fig. 3-4.sakaishimachibun, agano-mura, hannōshi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur”.holotype: pl. 7, fig. 3, spécimen n° nsmp1-18120e, national science museum, tokyo (japon) macroporella maxima endo 1952 1952b macroporella maxima n. sp.endo, pl. i, fig. 3-9.kitakami river, maiya-machi, tome-gun, miyagiken, honshū (japon): permien “moyen”.“cotypes” (syntypes): pl. i, fig. 6, spécimen n° 10793, lame mince n° 108; pl. i, fig. 7, spécimen n° 10796, lame mince n° 109, department of earth sciences, saitama university, urawa (japon) 1954 macroporella maxima .endo in endo & kanuma, pl. xvi, fig. 8; pl. xvii, fig. 7-8.sw kuchibora valley, nishiwara-mura, gujō-gun, gifu-ken, honshū (japon): permien inférieur-moyen (kuchibora fm, zone à p s e u d o f u s u l i n a zone à p a r a f u s u l i n a ); pl. xvi, fig. 7 & 9.iwa, tominoho-mura, mugi-gun, gifu-ken, honshū (japon): permien inférieur-moyen (kuchibora fm, zone à p s e u d o f u s u l i n a zone à parafusulina ) 1961a macroporella maxima .endo, pl. 2, fig. 9, extrait de endo (1952b: pl. i, fig. 6) 1961b macroporella maxima .endo, pl. 6, fig. 1-2.s minami-toba-ue, nagahama-shi, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 16, fig. 6.e o _ nogi, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien “moyen” / partie inférieure (o _ nogi fm) 1961c macroporella maxima .endo, pl. 3, fig. 6.kaerimizu, mitōc hō, ne mine-shi, yamaguchi-ken, honshū (japon): permien (akiyoshi limestone group) 1963 macroporella maxima .johnson, pl. 59, fig. 5, extrait de endo & kanuma (1954: pl. xvi, fig. 7) 1963 non macroporella maxima .johnson, pl. 59, fig. 6, extrait de endo (1957: pl. 38, fig. 9) 1963 macroporella sp.johnson, pl. 59, fig. 7, extrait de endo & kanuma (1954: pl. xvi, fig. 8) 1971 macroporella maxima .ishijima et al., pl. 8, fig. 1-2.sakaishimachibun, agano-mura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur” 1972 macroporella maxima .homann, pl. 6, fig. 46.nw zottach-kogel, kärnten (autriche): sakmarien (rattendorfer schichten, oberer pseudoschwagerinenkalk) 1980 macroporella maxima .e. flügel & flügel-kahler, pl. 4, fig. 3.nw mte covolo / seikofel, ese sesto / sexten, trentino alto adige (italie): permien inférieur (kalkbrekzie) 1981 macroporella maxima .nakamura, pl. 9, fig. 4-6.ishiyama, o _ no-chō tanigumi-mura, gifu-ken, honshū (japon): permien (ishiyama limestone) 1984 macroporella maxima .e. flügel, kochansky-devidé & ramovπ, pl. 28, fig. 5.bled (slovénie): permien “moyen” macroporella mina endo 1957 1954 m a c r o p o r e l l a sp.endo in endo & kanuma, pl. xvii, fig. 1.hachiman-machi, gujō-gun, gifu-ken, honshū (japon): permien inférieur (okuzumi fm / partie inférieure, zone à pseudofusulina) 97granier & grgasoviê: les algues dasycladales du permien et du trias... 1957 macroporella mina n. sp.endo, pl. 38, fig. 4-6.misaka, shinsaka-mura, jinseki-gun, hiroshima-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie inférieure).syntypes: pl. 38, fig. 45, lame mince n° 496; pl. 38, fig. 6, lame mince n° 497, department of earth sciences, saitama university, urawa (japon) 1961b macroporella mina .endo, pl. 13, fig. 5.sukawa, santō -machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm) 1962 (?) macroporella aff. mina.kochansky-devidé & milanoviê, pl. vi, fig. 2.krπ, s mojkovac, rivière tara, monténégro (yougoslavie): sakmarien supérieur ou artinskien inférieur 1967 (?) macroporella mina .pelhâte-peron, pl. viii, fig. 86.louverne, nne laval, mayenne (france): carbonifère, dinantien, viséen supérieur (v3a) 1969 (?) macroporella mina .pelhâte-peron, pl. vi, fig. 79, extrait de pelhâte-peron (1967: pl. viii, fig. 86) macroporella multiporosa endo et horiguchi 1957 1952a macroporella sp.endo, pl. 12, fig. 1.sakamotozawa, hikoroichi-mura, kesen-gun, iwate-ken, honshū (japon): permien “inférieur” 1957 macroporella multiporosa n. sp.endo & horiguchi, pl. xiv, fig. 4-6.kamitakara-mura, fukuji, gifuken, honshū (japon): permien inférieur (ichinotani group, zone à p s e u d o s c h w a g e r i n a ).“syntypes”: pl. xiv, fig. 4, lame mince n° 595; pl. xiv, fig. 5, lame mince n° 596; pl. xiv, fig. 6, lame mince n° 597 (non 596), department of earth sciences, saitama university, urawa (japon) 1959 macroporella multiporosa .endo, pl. 31, fig. 8-10.hatahoko, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien inférieur (gonbō fm, zone à parafusulina = zone à pseudofusulina) 1961c macroporella multiporosa .endo, pl. 1, fig. 6.konokami-yama, mine-shi, yamaguchi-ken, honshū (japon): permien inférieur (akiyoshi limestone group, zone à pseudoschwagerina , sous-zone à pseudo fusulina vulgaris); pl. 2, fig. 4.shigeyasu o _ mine, n mine-shi, yamaguchi-ken, honshū (japon): permien moyen (akiyoshi limestone group, zone à neoschwagerina craticulifera ) macroporella nuda endo 1969, nom. nud. 1 9 6 9 (nom. nud.) macroporella nuda n. sp.endo, pl. xi, fig. 10; pl. xiv, fig. 1-8.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à c a n c e l l i n a).type non désigné: pl. xi, fig. 10; pl. xiv, fig. 3, lame mince n° gk.d 13050; pl. xiv, fig. 1-2, 4, 6 & 8, lames minces n° gk.d 13727, 13292, 13037, 13039 & 13040; pl. xiv, fig. 5 & 7, lame mince n° gk.d 13294, kyūshū university, fukuoka (japon) macroporella ? nyugawensis endo 1959, nom. nud. 1 9 5 9 (nom. nud.) macroporella ? nyugawensis n. sp.endo, pl. 32, fig. 5.yokoberadani valley, hatahoko, n yūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien moyen (o _ zu fm, zone à n e o s c h w a g e r i n a); pl. 32, fig. 6.sotedani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien inférieur (gonbō fm, zone à p a r a f u s u l i n a = zone à p s e u d o f u s u l i n a).“holotype” (syntypes): pl. 31, fig. 5, lame mince n° 21149; pl. 31, fig. 6, lame mince n° 21158, geol. min. inst., tokyo kyoiku daigaku [tokyo university of education ] (japon) macroporella perforatissima pia 1920 1920 macroporella perforatissima n. sp.pia, pl. ii, fig. 1-3.furthof, türnitz, niederösterreich (autriche): anisien (reiflinger kalk).types: pl. ii, fig. 1-3, collection j. von pia, naturhistorisches museum, wien (autriche) 1969 macroporella perforatissima .diaconu & dragastan, pl. ii, fig. 2.dealul glimeia, apuseni mts (roumanie): ladinien 1973 m a c r o p o r e l l a p e r f o r a t i s s i m a .popa & dragastan, pl. xv, fig. 57 pars, 58 & 60 pars.e lorǎu, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à dadocrinus communis) 1980 macroporella perforatissima .dragastan, pl. iv, fig. 8 pars, extrait de popa & dragastan (1973: pl. xv, fig. 57) 1982 macroporella perforatissima .casati et al., pl. 35, fig. 2.c & 4.col vidàl, s auronzo di cadore, véneto (italie): anisien, pelsonien ? illyrien (fm del serla superiore) 98 geologia croatica 53/1 macroporella phlongphrabensis endo 1968, nom. nud. 1968b (nom. nud.) macroporella phlongphrabenis n. sp.endo, “chart”, non figurée.type non figuré macroporella preromangica praturlon 1963 [cf. aciculella preromangica (praturlon 1963) ott 1974 ] macroporella retica zanin buri 1965 [synonyme postérieur de griphoporella curvata (gümbel 1872) pia 1915, emend. barattolo et al. 1993 ] macroporella siamensis endo 1969 1969 macroporella siamensis n. sp.endo, pl. xii, fig. 6-11.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à c a n c e l l i n a ). holotype: pl. xii, fig. 6, lame mince n° gk.d 13958, kyūshū university, fukuoka (japon) macroporella sondaica pia 1924 1924a macroporella sondaica n. sp.pia, pl. i, fig. 1-7.flusse bula besar, sw bula, e seran (indonésie): n o r i e n.types: pl. i, fig. 1-7, lame mince n° ?, collection j. von pia, naturhistorisches museum, wien (autriche) macroporella spectabilis bystrický 1962 [cf. salpingoporella spectabilis (bystrický 1962) emberger 1979 ] macroporella sturi bystrický 1967 [cf. salpingoporella sturi (bystrický 1967) emberger 1979 ] macroporella tenuimarginata endo 1961 1961b macroporella tenuimarginata n. sp.endo, pl. 7, fig. 2.e o _ nogi, santō-machi, sakata-gun, shiga-ken, h o n s hū (japon): permien “moyen” / partie inférieure (o _ nogi fm); pl. 7, fig. 3.yadani valley, shigaken, honshū (japon): permien “inférieur” (kiyotaki fm); pl. 7, fig. 4.muraki, ibuki-mura, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm).holotype: pl. 7, fig. 3, lame mince n° 52068-10, geological survey of japan (japon) 1980 (?) macroporella a f f . t e n u i m a r g i n a t a .e. flügel & flügel-kahler, pl. 4, fig. 1 & 6.s trogkofel / creta di aip, friuli venezia giulia (italie): permien inférieur (trogkofelkalk) macroporella tetrapora pia 1937 1937 macroporella tetrapora n. sp.pia, pl. 10(94), fig. 4.batu mentjada, djambi, sumatra (indonésie): permien “inférieur”-”moyen”.type: pl. 10(94), fig. 4, collection a. tobler, naturhistor. mus. basel (suisse) macroporella thailandensis endo 1969, nom. nud. 1969 (nom. nud.) macroporella thailandensis n. sp.endo, pl. xii, fig. 1-5.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à c a n c e l l i n a ).type non désigné: pl. xii, fig. 1-4, lame mince n° gk.d 39-a; pl. xii, fig. 5, lame mince n° gk.d 13002, kyūshū university, fukuoka (japon) macroporella toriyamai endo 1969, non 1968 1968b (nom. nud.) macroporella toriyamai n. sp.endo, “chart”, non figurée.type non figuré 1969 macroporella toriyamai n. sp.endo, pl. xiii, fig. 1-8.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à c a n c e l l i n a ). holotype: pl. xiii, fig. 1, lame mince n° gk.d 13058, kyūshū university, fukuoka (japon) 99granier & grgasoviê: les algues dasycladales du permien et du trias... macroporella verticillata pia 1940, non soka» et nikler 1973 1908 g u a d a l u p i a ? sp. var.girty, pl. xxvii, fig. 11-12.s delaware mts, texas (états-unis d’amérique): permien (delaware mt fm) 1940a macroporella verticillata n. nom.pia, p. 55, non figurée.types: pl. xxvii, fig. 11-12 in g.h. girty (1908), lames minces n° ro 118/3 & ro 118/2, collection g.h. girty, = u.s. national museum 118143, smithsonian institution, washington (états-unis d’amérique) 1978a macroporella c f . v e r t i c i l l a t a .mamet & roux, pl. 1, fig. 1, extrait de girty (1908: pl. xxvii, fig. 11); pl. 1, fig. 2, extrait de girty (1908: pl. xxvii, fig. 12) 1985 macroporella cf. verticillata .roux, pl. 4, fig. 1, extrait de girty (1908: pl. xxvii, fig. 11) 1988 macroporella verticillata .deloffre, pl. 2, fig. 14, extrait de girty (1908: pl. xxvii, fig. 12) mizzia schubert 1909, non 1907, emend. rezak 1959 mizzia bramkampi rezak 1959 1959 mizzia bramkampi n. sp.rezak, pl. 72, fig. 4 & 14.forage damman 43, hasa province (arabie saoudite): permien “moyen” terminal “supérieur” (khuff fm).holotype: pl. 72, fig. 4, lame mince usgs a144b2, u.s. geological survey, denver federal center, denver, colorado (états-unis d’amérique) mizzia cornuta kochansky et herak 1960 1960 m i z z i a c o r n u t a n. sp.kochansky & herak, fig. 4.1 [= pl. vii, fig. 8], 4.2 [= pl. vii, fig. 2], 4.3 [= pl. vii, fig. 3], 4.4 [= pl. vii, fig. 1], 4.5 [= pl. vii, fig. 11], 4.6 [= pl. vii, fig. 7], 4.7 [= pl. vii, fig. 6] & 4.8 [= pl. vii, fig. 4]; pl. vii, fig. 1-8 & 11.matkoviê, nw bar, s monténégro (yougoslavie): léonardien supérieur wordien inférieur (galets dans un conglomérat anisien); fig. 4.9 [= pl. vii, fig. 13]; pl. vii, fig. 13.turëini, bar, s monténégro (yougoslavie): wolfcampien moyen; fig. 4.10 [= pl. vii, fig. 1 4] & 4.11 [= pl. vii, fig. 12]; pl. vii, fig. 12 & 14.crne grede, velebit mt (croatie): permien “moyen”-”supérieur”; fig. 4.12 [= pl. vii, fig. 10]; pl. vii, fig. 9-10.bohinjska bela, sw bled (slovénie): wordien supérieur.holotype: fig. 4.2 [= pl. vii, fig. 2 ]; pl. vii, fig. 2, lame mince n° 1029, geoloπko-paleontoloπki zavod, prirodoslovno-matematiëki fakultet [geological and palaeontological institute, faculty of science ], zagreb (croatie) 1962 mizzia cornuta .kochansky-devidé & milanoviê, pl. vi, fig. 4-5.krπ, s mojkovac, rivière tara, monténégro (yougoslavie): sakmarien supérieur ou artinskien inférieur 1962 (?) m i z z i a ? cf. c o r n u t a .kochansky-devidé & milanoviê, pl. vi, fig. 7.krπ, s mojkovac, rivière tara, monténégro (yougoslavie): sakmarien supérieur ou artinskien inférieur 1963 mizzia cornuta.herak, fig. 30 (en bas, à droite), extrait de kochansky & herak (1960: pl. vii, fig. 2) 1963 mizzia cornuta .pantiê, pl. ix, fig. 4-7.sw haj nehaj, miπiêi, kotor, monténégro (yougoslavie): permien “supérieur” (dans un conglomérat anisien) 1964a mizzia cornuta .kochansky-devidé, pl. iv, fig. 2 pars.egeljac ©iloviê, velebit mt (croatie): permien “supérieur” 1965 (?) m i z z i a cf. c o r n u t a .ramovπ & kochansky-devidé, pl. i, fig. 1; pl. ix, fig. 9.ortnek (slovénie): permien 1969 mizzia cornuta.pantiê, pl. i, fig. 2-3.dolovsko brdo, w serbie (yougoslavie): permien “supérieur” 1970a mizzia cornuta .kochansky-devidé, pl. xviii, fig. 9 pars; pl. xxiii, fig. 1-4.w karavanke (slovénie): permien inférieur (trogkofelkalk) 1972 mizzia cornuta .homann, pl. 5, fig. 40.nw zottach-kogel, kärnten (autriche): sakmarien (rattendorfer schichten, oberer pseudoschwagerinenkalk) 1974 (?) mizzia cf. cornuta .mirkoviê, pl. vii, fig. 1.luæac, ivangrad, e monténégro (yougoslavie): sakmarien 1974 (?) m i z z i a c o r n u t a .mirkoviê, pl. x, fig. 2.lacina voda, mujiêa reëina, e monténégro (yougoslavie): sakmarien 1977 mizzia cornuta.e. flügel, pl. 3/4 pars.velebit mt (croatie): permien “moyen” 1978 m i z z i a c o r n u t a .anelkoviê, pl. xxxix, fig. 1-4, extrait de kochansky-devidé (1970a: pl. xxiii, fig. 1-4); pl. xl, fig. 4, extrait de kochansky & herak (1960: pl. vii, fig. 5); pl. xlvii, fig. 10, extrait de 100 geologia croatica 53/1 kochansky & herak (1960: pl. vii, fig. 1); pl. xlvii, fig. 11, extrait de kochansky & herak (1960: pl. vii, fig. 9); pl. xlvii, fig. 12, extrait de kochansky & herak (1960: pl. vii, fig. 2) 1978 m i z z i a c o r n u t a .kulik, pl. viii, fig. 5-6.shakhtau massif, bashkirskaya (fédération de russie): sakmarien, tastubien (zone à pseudofusulina moelleri , sous-zone ts1); pl. viii, fig. 7.shakhtau massif, bashkirskaya (fédération de russie): assélien, kurmainskien (zone à schwagerina moelleri et p s e u d o fusulina fecunda, zone ass2) 1979 mizzia cornuta .ramovπ & kochansky-devidé, pl. 2, fig. 3 pars.n julijske alpe (slovénie): artinskien (trogkofelkalk) 1980 mizzia cornuta.e. flügel & flügel-kahler, pl. 2, fig. 9-10.ne col mezzodì, forni avoltri, friuli venezia giulia (italie): permien inférieur (trogkofelkalk) 1982 mizzia cornuta.mu, pl. viii, fig. 6.xizang / tibet (chine populaire): permien “inférieur” / partie supérieure 1983 mizzia cornuta.jenny-deshusses, pl. 16, fig. 4.kuh e jamal, tabas, e téhéran (iran): murghabien moyen (jamal fm) 1984 mizzia cornuta.e. flügel, kochansky-devidé & ramovπ, pl. 29, fig. 6.bohinjska bela, sw bled (slovénie): permien “moyen”; pl. 29, fig. 8-9.straæa, bled (slovénie): permien “moyen” 1989 mizzia cornuta.vachard, pl. 7, fig. 1.pulau apat, jambi province, sumatra (indonésie): assélien moyen-sakmarien (assélien supérieur probable) 1990 mizzia cornuta.dragastan et al., pl. i, fig. 1; pl. ii, fig. 3 & 8 pars.sakesar, salt range (pakistan): murghabien supérieur djulfien supérieur (wargal fm) 1991 mizzia cornuta.e. flügel et al., pl. 47, fig. 1.e pietra di salomone, sw palazzo adriano, sw prizzi, sicile (italie): permien fig. 16 m i z z i a cornuta (kochansky & herak, 1960, pl. vii, fig. 2), x44. fig. 17 m i z z i a cornuta (kochansky & herak, 1960, pl. vii, fig. 6), x44. 101granier & grgasoviê: les algues dasycladales du permien et du trias... 1991 mizzia cornuta.sremac, pl. 7, fig. 1 pars & 2 pars.milaπnovac, bruπane, baπke oπtarije, velebit mt (croatie): murghabien (zone à neoschwagerina craticulifera ) 1992 mizzia cornuta.vachard et al., pl. iii, fig. 8.n ban na wai, nw thaïlande (thaïlande): murghabien supérieur midien 1993 mizzia cornuta .vachard et al., pl. i, fig. 4; pl. vii, fig. 14.s ermióni, argolís (grèce): djulfien (galet dans une “coulée boueuse” kimméridgienne de la fm de potami) 1997 mizzia cornuta.pantiê-prodanoviê, pl. i, fig. 4.dvorska, n krupanj, nw serbie (yougoslavie): permien supérieur mizzia japonica karpinsky 1909 1909a mizzia japonica n. sp.karpinsky, pl. iii, fig. 2.a-c & 5.a-c.kinshō-zan hill, mino-akasaka, n o _ g a k i shi, gifu-ken, honshū (japon): permien (s c h w a g e r i n a l i m e s t o n e ).types: pl. iii, fig. 2.a-c & 5.a-c, coll. a. karpinsky 1909b mizzia japonica n. sp.karpinsky, pl., fig. 2.a-c & 5.a-c, extrait de karpinsky (1909a: pl. iii, fig. 2.a-c & 5.a-c) 1942 mizzia japonica.johnson & dorr, pl. 10, fig. 4 pars, extrait de karpinsky (1909a: pl. iii, fig. 2.a-c & 5.a-c) mizzia longiporosa endo 1961 1961c mizzia longiporosa n. sp.endo, pl. 1, fig. 5; pl. 2, fig. 5-6.yamaguchi-ken, honshū (japon): permien (akiyoshi limestone group); pl. 3, fig. 1.s hagiwara, ofuku, n mine-shi, yamaguchi-ken, honshū (japon): permien supérieur (akiyoshi limestone group, zone à yabeina shiraiwensis); pl. 4, fig. 4.kaerimizu, mitōc hō, ne mine-shi, yamaguchi-ken, honshū (japon): permien (akiyoshi limestone group).holotype: pl. 1, fig. 5, lame mince n° 2267a, dept. of geology, ky ūshū university, fukuo ka (japon) 1971 mizzia longiporosa.ishijima et al., pl. 3, fig. 4-5.sakaishimachibun, agano-mura, hannō-shi, irumagun, saitama-ken, honshū (japon): permien “inférieur” 1974 mizzia longiporosa.mu, pl. 167, fig. 7.sw chine (chine populaire) 1982 (?) mizzia cf. l o n g i p o r o s a .mu, pl. vi, fig. 5-6.xizang / tibet (chine populaire): permien “inférieur” / partie supérieure mizzia minuta johnson et dorr 1942 1942 mizzia minuta n. sp.johnson & dorr, pl. 9, fig. 2; pl. 12, fig. 2.apache mts, texas (états-unis d’amérique): guadalupien.types: pl. 9, fig. 2; pl. 12, fig. 2, lame mince n° ?, collection h.j. john son, colorado school of mines, golden, colorado (états-unis d’amérique) 1942 mizzia minuta.johnson, pl. 4, fig. 4, extrait de johnson & dorr (1942: pl. 9, fig. 2); pl. 5, fig. 4 (= pl. 3, fig. 2), extrait de johnson & dorr (1942: pl. 12, fig. 2) 1942 mizzia velebitana.johnson, pl. 3, fig. 2 (= pl. 5, fig. 4), extrait de johnson & dorr (1942: pl. 12, fig. 2) 1944 mizzia velebitana.johnson, pl. 302, fig. 1, extrait de johnson & dorr (1942: pl. 12, fig. 2) 1951 mizzia minuta.johnson, pl. 10, fig. 4.apache mts, texas (états-unis d’amérique): guadalupien (probablement ? capitanien) 1954 mizzia minuta.endo, pl. xviii, fig. 3.s kinshō-zan hill, mino-akasaka, n o _ gaki-shi, gifu-ken, honshū (japon): permien “supérieur” 1959 mizzia minuta.bilgütay, pl. ii, fig. 2.hazro, diyarbakir (turquie): permien “supérieur” 1963 mizzia minuta.johnson, pl. 62, fig. 1, extrait de johnson & dorr (1942: pl. 9, fig. 2) 1965 (?) mizzia cf. m. minuta.johnson & kaska, pl. 3, fig. 4; pl. 4, fig. 3.? san luis (guatemala): permien 1995 m i z z i a m i n u t a.kirkland, pl. 1, fig. 3.walnut canyon, guadalupe mts, new mexico (états-unis d’amérique): kazanien (carlsbad group, tansill fm) mizzia pseudocornuta kulik 1978 1978 mizzia pseudocornuta n. sp.kulik, pl. viii, fig. 3-4.shakhtau massif, bashkirskaya (fédération de russie): sakmarien, tastubien (zone à pseudofusulina moelleri , sous-zone ts1).holotype: pl. viii, fig. 102 geologia croatica 53/1 3, lame mince n° 4513/67, collection e.l. kulik, geologicheski institut akademije nauk sssr (fédération de russie) mizzia sakaishiensis ishijima et al. 1971 1971 mizzia sakaishiensis n. sp.ishijima et al., pl. 3, fig. 6-7.sakaishimachibun, agano-mura, hannōs h i , iruma-gun, saitama-ken, honshū (japon): permien “inférieur”.holotype: pl. 3, fig. 6, spécimen n° nsmp1-18091a, national science museum, tokyo (japon) mizzia tauridiana güvenç 1965, nom. nud. 1 9 6 5 (nom. nud.) mizzia tauridiana n. sp.güvenç, pl. a7, fig. 1-2 & 10.imanli col de hortubeleni, vallée du dikenli dere, alanya (turquie): permien “inférieur”.holotype: pl. a7, fig. 1, lame mince n° t.g.577, collection t. güvenç, laboratoire de micropaléontologie, faculté des sciences de paris (france) *mizzia velebitana schubert 1909, emend. rezak 1959 1908 g u a d a l u p i a ? sp.girty, pl. v, fig. 7-10.el capitan, guadalupe mts, new mexico (états-unis d’amérique): guadalupien (capitan fm) 1909 mizzia velebitana n. gen. n. sp.schubert, pl. xvi, fig. 8 pars, 9, 10 pars, 11 & 12 (à droit).paklenica, velebit mt (croatie): “carbonifère supérieur”.validation du genre; types: pl. xvi, fig. 8 pars, 9, 10 pars, 11 & 12 (à droit), collection r.j. schubert 1909a mizzia velebitana.karpinsky, pl., fig. 6.a, 6.c-d, 6.j-l, 7.b, 7.e, 7.h, 8 pars & 9.f-g.velebit mt (croatie) 1909a (?) m i z z i a cf. v e l e b i t a n a.karpinsky, pl., fig. 1.a-c, 3, 4.a-d & 13.a-b.kinshō-zan hill, mino-akasaka, n o _ gaki-shi, gifu-ken, honshū (japon): permien (schwagerina limestone) 1909b mizzia velebitana.karpinsky, pl. iii, fig. 6.a, 6.c-d, 6.j-l, 7.b, 7.e, 7.h, 8 pars & 9.f-g, extrait de karpinsky (1909a: pl., fig. 6.a, 6.c-d, 6.j-l, 7.b, 7.e, 7.h, 8 pars & 9.f-g) 1909b (?) m i z z i a cf. v e l e b i t a n a .karpinsky, pl. iii, fig. 1.a-c, 3, 4.a-d & 13.a-b, extrait de karpinsky (1909a: pl., fig. 1.a-c, 3, 4.a-d & 13.a-b) 1915 mizzia velebitana.négris (pia), fig. 8 pars.gourissi, parnassós mts (grèce): “carbonifère” 1919 mizzia velebitana.négris, fig. 56-57.gourissi, parnassós mts (grèce): “carbonifère”; fig. 59.khíos / chios (grèce): “carbonifère” 1919 vermiporella cf. velebitana.négris, pl. xxvi, fig. 1.gourissi, parnassós mts (grèce): “carbonifère” 1920 mizzia velebitana.pia, pl. i, fig. 12, 14-19 & 22-23.paklenica, velebit mt (croatie): “carbonifère supérieur”; pl. i, fig. 13 & 20-21.paklenica, velebit mt (croatie): “carbonifère supérieur” (dolomie à mizzia) 1925 mizzia velebitana.ozawa, pl. i, fig. 1.a & 2.a; pl. ii, fig. 6.b & 7.c.nagato, honshū (japon): permien 1927 non mizzia velebitana.ogilvie gordon, pl. ix, fig. 8.plesch d’inaz, val gardena / grödnertal, trentino alto adige (italie): permien supérieur (bellerophon fm) 1933 mizzia velebitana.simiê, pl. ix, fig. 1-2.serbie (yougoslavie): permien “inférieur” 1934 mizzia velebitana.heritsch, pl. ii, fig. 16.monténégro (yougoslavie): permien “supérieur” 1937 mizzia velebitana.pia, pl. 9(93), fig. 3; pl. 10(94), fig. 3 pars.carlsbad, guadalupe mts, new mexico (états-unis d’amérique): guadalupien 1940 mizzia velebitana.makhaev, pl. i, fig. 1, 3 & 11.rivière kara-sou, e pamir (tadjikistan): permien; pl. i, fig. 2.koubergandy, e pamir (tadjikistan): permien 1941b mizzia velebitana.pia, fig. 3-4.carlsbad, guadalupe mts, new mexico (états-unis d’amérique): guadalupien (capitankalk) 1942 mizzia velebitana.johnson & dorr, pl. 9, fig. 1 & 3-4; pl. 10, fig. 2 & 5.apache mts, texas (étatsunis d’amérique): guadalupien; pl. 10, fig. 4 pars, extrait de karpinsky (1909a: pl., fig. 1.a-c, 3, 4.a-d, 6.a, 6.c-d, 6.j-l, 7.b, 7.e & 7.h); pl. 11, fig. 1-2.guadalupe mts, new mexico (états-unis d’amérique): guadalupien 1942 mizzia velebitana.johnson, pl. 2, fig. 1, extrait de johnson & dorr (1942: pl. 9, fig. 1); pl. 2, fig. 2, extrait de johnson & dorr (1942: pl. 9, fig. 3); pl. 2, fig. 3, extrait de johnson & dorr (1942: pl. 9, fig. 4); pl. 2, fig. 4.apache mts, texas (états-unis d’amérique): guadalupien; pl. 3, fig. 1, extrait de johnson & dorr (1942: pl. 10, fig. 5); pl. 3, fig. 3, extrait de johnson & dorr (1942: pl. 10, fig. 2) 103granier & grgasoviê: les algues dasycladales du permien et du trias... 1942 non mizzia velebitana [= m i z z i a m i n u t a].johnson, pl. 3, fig. 2 (= pl. 5, fig. 4), extrait de johnson & dorr (1942: pl. 12, fig. 2) 1943 mizzia limestone.johnson, fig. 20, extrait de johnson & dorr (1942: pl. 9, fig. 1); fig. 20, extrait de johnson & dorr (1942: pl. 11, fig. 3) 1944 non mizzia velebitana [= m i z z i a m i n u t a].johnson, pl. 302, fig. 1, extrait de johnson & dorr (1942: pl. 12, fig. 2) 1945 mizzia.johnson, pl. 53, fig. 21.apache mts, texas (états-unis d’amérique): permien 1946a mizzia velebitana.johnson, pl. 1, fig. 1, extrait de johnson & dorr (1942: pl. 9, fig. 4); pl. 1, fig. 2, extrait de johnson & dorr (1942: pl. 11, fig. 3) 1951 m i z z i a.johnson, pl. 6, fig. 3 pars.apache mts, texas (états-unis d’amérique): guadalupien (probablement ? capitanien) 1951 mizzia velebitana.johnson, pl. 7, fig. 1-4.apache mts, texas (états-unis d’amérique): guadalupien (probablement ? capitanien) 1952a mizzia velebitana.endo, pl. 12, fig. 5.sakamotozawa, hikoroichi-mura, kesen-gun, iwate-ken, honshū (japon): permien “moyen” 1952b mizzia velebitana.endo, pl. i, fig. 2.kitakami river, maiya-machi, tome-gun, miyagi-ken, honshū (japon): permien “moyen” 1952 (?) mizzia velebitana.konishi, pl. 14, fig. 11 & 12 pars.dodo, n yanahara mine, kitawake-mura, katsuta-gun, okayama-ken, honshū (japon): permien moyen ? supérieur (zone à yabeina, avec neoschwa gerina craticulifera ) 1953a mizzia velebitana.endo, pl. xi, fig. 1-2.iwaizaki, motoyoshi-gun, kitakami mts, honshū ( j a p o n ) : permien “supérieur” 1954 mizzia velebitana.endo, pl. xviii, fig. 1-2.s kinshō-zan hill, mino-akasaka, n o _ gaki-shi, gifu-ken, honshū (japon): permien “supérieur” 1954 mizzia velebitana.endo in endo & kanuma, pl. xiv, fig. 8.kayu-gawa, takeda-mura, gujō g u n , gifu-ken, honshū (japon): permien moyen (kayugawa fm, zone à n e o s c h w a g e r i n a-v e r b e e c k i n a); pl. xiv, fig. 9.managawa river, nishino-tani-mura, o _ no-gun, fukui-ken, honshū (japon): permien “supérieur” (galet dans le motodo conglomerate) 1954 m i z z i a.johnson, pl. 35, fig. 1, extrait de johnson & dorr (1942: pl. 9, fig. 1); pl. 35, fig. 3, extrait de johnson (1942: pl. 2, fig. 4) 1954 mizzia velebitana.schréter, pl. ii, fig. 5.hátar, ne szarvaskö, bükk hegység, heves (hongrie): permien 1955 mizzia velebitana.endo & hashimoto, fig. 2.penke river, nishiokoppe-mura, w monbetsu-shi, w abashiri province, hokkaidō (japon): permien (galet dans un conglomérat de la nakaokoppe fm) 1955 mizzia velebitana.kochansky-devidé & ramovπ, pl. iv, fig. 10 pars; pl. v, fig. 9 pars; pl. vii, fig. 7 pars.bohinjska bela, sw bled (slovénie): wordien supérieur (neoschwagerinski skladi, zone à p a r a fusulina et neoschwagerina) 1956 mizzia velebitana.endo, pl. 22, fig. 3-8.shōm u r a tōge pass & shimokuzū, agano-mura, hannōs h i , iruma-gun, saitama-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne) 1956 mizzia velebitana.jones, fig. 4.2, extrait de johnson (1951: pl. 7, fig. 1 pars) 1956 non mizzia velebitana [= mizzia yabei].jones, fig. 4.6, extrait de johnson & dorr (1942: pl. 12, fig. 3) 1956 mizzia.papastamatiou & reichel, fig. 1.presqu’île de siteia, kriti (grèce): permien 1957 mizzia velebitana.endo, pl. 37, fig. 4-5.zenbutsuji-dani, taishaku-mura, hiba-gun, hiroshima-ken, h o n s hū (japon): permien “inférieur” (yukisawa subsystem / partie supérieure); pl. 44, fig. 3, extrait de endo & hashimoto (1955: fig. 2) 1958 mizzia velebitana.kiss, pl. i, fig. 2 & 3 pars.sirok, mátra hegység, heves (hongrie): permien “supérieur” 1958 mizzia velebitana.marinos & reichel, pl. iii, fig. 3.orthrys mt (grèce): permien 1959 mizzia velebitana.bilgütay, pl. i, fig. 2-3; pl. ii, fig. 1.hazro, diyarbakir (turquie): permien “supérieur” 1959 mizzia velebitana.endo, pl. 30, fig. 2.hatahoko, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien (gonbō fm, zone à p a r a f u s u l i n a = zone à p s e u d o s c h w a g e r i n a [s i c]); pl. 31, fig. 1.otani, horadani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien (o _ zu fm) 104 geologia croatica 53/1 1959 mizzia velebitana emend.rezak, pl. 72, fig. 1-3, 5-6, 8-10, 12-13 & 15-19.forage damman 43, hasa province (arabie saoudite): permien “moyen” terminal-”supérieur” (fm khuff) 1960 m i z z i a v e l e b i t a n a.kochansky & herak, pl. v, fig. 1 & 9-12.bruπane, velebit mt (croatie): permien “moyen”-”supérieur”; pl. v, fig. 2, 4 & 6.pariêa livada, velika paklenica, velebit mt (croatie): permien “moyen”-”supérieur”; pl. v, fig. 3 & 5.crne grede, velebit mt (croatie): permien “moyen””supérieur” 1961a mizzia velebitana.endo, pl. 7, fig. 10, extrait de endo in endo & kanuma (1954: pl. xiv, fig. 8) 1961b mizzia velebitana.endo, pl. 4, fig. 1.e o _ nogi, santō-machi, sakata-gun, shiga-ken, honshū ( j a p o n ) : permien “moyen” / partie inférieure (o _ nogi fm); pl. 4, fig. 2-3.w nagaoka, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm) 1961c mizzia velebitana.endo, pl. 4, fig. 5.yobara-w irimi, o _ mine, nw mine-shi, yamaguchi-ken, honshū (japon): permien supérieur (akiyoshi limestone group, zone à yabeina shiraiwensis) 1961 mizzia velebitana.hanzawa, pl. lxix, fig. 1.hiruii, aohaka, akasaka-chō, fuha-gun, gifu-ken, hons hū (japon): permien supérieur, ‘basleo’ (akasaka limestone, zone à y a b e i n a); pl. lxix, fig. 2 pars.okubo, akasaka-chō, fuha-gun, gifu-ken, honshū (japon): permien supérieur, ‘basleo’ (akasaka limestone, zone à yabeina) 1961 mizzia.johnson, pl. 46, fig. 1 pars, extrait de johnson & dorr (1942: pl. 9, fig. 1); pl. 46, fig. 3, extrait de johnson (1954: pl. 35, fig. 3); pl. 128, fig. 1 pars, extrait de johnson (1951: pl. 6, fig. 3); pl. 128, fig. 2 pars, extrait de johnson & dorr (1942: pl. 9, fig. 1) 1961 diplopora sp.villa, pl. xxxi, fig. 4.c.gola di balula, bamian chorband, nw kaboul (afghanistan): permien (“calcari di balula”) 1963 mizzia velebitana.h. flügel, pl. 1, fig. 3.aladag / bademli, ne alanya (turquie): permien 1963 m i z z i a v e l e b i t a n a .herak & kochansky, pl. i, fig. 6.szodonka völgy, bükk hegység (hongrie): permien “supérieur”; pl. iv, fig. 4-6.nagyvisnyó, bükk hegység, heves (hongrie): permien “supérieur” 1963 m i z z i a v e l e b i t a n a.herak, fig. 30 (en haut, à gauche), extrait de kochansky & herak (1960: pl. v, fig. 12); fig. 30 (en haut, au centre), extrait de kochansky & herak (1960: pl. v, fig. 1); fig. 30 (en haut, à droite), extrait de kochansky & herak (1960: pl. v, fig. 6) 1963 mizzia velebitana.johnson, pl. 62, fig. 2, extrait de endo (1957: pl. 37, fig. 4); pl. 62, fig. 3, extrait de johnson (1951: pl. 7, fig. 3); pl. 61, fig. 1 pars, extrait de johnson & dorr (1942: pl. 9, fig. 1); pl. 60, fig. 1 pars = pl. 61, fig. 3, extrait de johnson (1942: pl. 2, fig. 4); pl. 62, fig. 4-5.honshū (japon): permien 1963 mizzia velebitana.pantiê, pl. ix, fig. 1-3 [pl. vii, fig. 2 pars & 4 pars].sw haj nehaj, miπiêi, kotor, monténégro (yougoslavie): permien “supérieur” (dans un conglomérat anisien) 1963 mizzia velebitana.praturlon, pl. v, fig. 1-4 & 7.comélico, pádola-auronzo di cadore, véneto (italie): permien supérieur (bellerophon fm / “b e l l e r o p h o n-zone” / partie sommitale); pl. v, fig. 5-6.preromang, val badia / gadertal, trentino alto adige (italie): permien supérieur (bellerophon fm / “bellerophon-zone” / partie sommitale) 1964 algues dasycladacées.glintzboeckel & rabaté, pl. xxxvi, fig. 2; pl. xxxvii, fig. 2.b.forage kirchaou, s gabes (tunisie): permien “moyen” 1964 algues.glintzboeckel & rabaté, pl. xxxvii, fig. 1.forage kirchaou, s gabes (tunisie): permien “moyen” 1964 (?) algues.glintzboeckel & rabaté, pl. lxx, fig. 2 pars; pl. lxxi, fig. 1.djebel tebaga (tunisie): permien “supérieur”; pl. ciii, fig. 2; pl. cvii, fig. 1 pars.forage bir soltane (tunisie): permien “supérieur” 1964 mizzia velebitana.glintzboeckel & rabaté; pl. lxxxvi, fig. 2 pars.djebel tebaga (tunisie): permien supérieur (zone à yabeina) 1964 mizzia.glintzboeckel & rabaté, pl. lxxxii, fig. 1.djebel tebaga (tunisie): permien “supérieur”; pl. lxxxiii, fig. 1 pars.djebel tebaga (tunisie): permien supérieur (zone à y a b e i n a); pl. cvi, fig. 1-2.forage bir soltane (tunisie): permien “supérieur” 1965 mizzia velebitana.güvenç, pl. m12, fig. 2.a; pl. a7, fig. 4-7.w taurus (turquie): permien “inférieur” terminal 1965 mizzia velebitana.johnson & kaska, pl. 4, fig. 6.? san luis (guatemala): permien 1966 mizzia velebitana.johnson & danner, pl. 56, fig. 1 & 3.e jesmond, nw porcupine creek, british columbia (états-unis d’amérique): permien “supérieur” (cache creek group, marble canyon fm); pl. 56, fig. 2.e jesmond, se mt bowman, british columbia (états-unis d’amérique): permien “supérieur” (cache creek group, marble canyon fm) 105granier & grgasoviê: les algues dasycladales du permien et du trias... 1967 mizzia velebitana.accordi & broglio loriga, pl. xv, fig. 5, extrait de praturlon (1963: pl. v, fig. 5) 1968a mizzia velebitana.elliott, pl. 13, fig. 1-2 & 4-5; pl. 14, fig. 1-4.ora, mosul liwa, n irak (irak): permien “supérieur” (darari fm); pl. 13, fig. 3.harur, mosul liwa, n irak (irak): permien “supérieur” 1968 mizzia velebitana.stevanoviê & anelkoviê, fig. 169.i, extrait de simiê (1933: pl. ix, fig. 1) 1969 mizzia velebitana.endo, pl. ix, fig. 7-9; pl. x, fig. 4-5.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina ) 1969 mizzia velebitana.pantiê, pl. ii, fig. 1-3.obradoviêi, w serbie (yougoslavie): permien “supérieur” 1970 mizzia velebitana.l.t. nguyên, pl. vi, fig. 6; pl. vii, fig. 1-4.phnom-sup-trup, ne sisophon (cambodge): permien “moyen” (phnom-sup-trup limestones); pl. vi, fig. 5.núi xà-ngách, hòn chông, se hà tiên, w hô chi minh-ville / saïgon (viêt-nam): kungurien (xà-ngách limestones); pl. vii, fig. 59.núi còm, hòn chông, se hà tiên, w hô chi minh-ville / saïgon (viêt-nam): kungurien supérieur ? kazanien inférieur (núi còm limestones); pl. vi, fig. 3-4; pl. vii, fig. 10; pl. viii, fig. 1-3.phnomcau-lan, s tuk-méas, kampot (cambodge): kazanien (phnom-cau-lan limestones) 1971 mizzia velebitana.lys & lapparent, pl. xx, fig. 2.bulola w hindou kouch (afghanistan): murghabien moyen (zone à neoschwagerina schuberti ) 1972 mizzia velebitana.homann, pl. 6, fig. 47.se schulterkofel, rattendorfer alpe, kärnten (autriche): sakmarien (rattendorfer schichten, unterer pseudoschwagerinenkalk) 1974 mizzia.glennie et al., fig. 5.24.7-8.(oman): permien (ibra fm); fig. 5.40.11.(oman): permien 1975 mizzia (?).wilson, pl. xiii (b).(bosnie-herzégovine, croatie, macédoine, slovénie, ou yougoslavie): permien 1976 mizzia velebitana.montenat et al., pl. xviii, fig. 13 pars.djebel akhdar, oman mts (oman): murghabien supérieur 1976 mizzia velebitana.vachard in montenat et al., pl. xix, fig. 3-4.djebel akhdar, oman mts (oman): murghabien supérieur 1977 mizzia velebitana.e. flügel, pl. 3/4 pars.velebit mt (croatie): permien “moyen” 1977 mizzia velebitana.vachard in h. termier et al., pl. 3, fig. 1 & 3.djebel tebaga (tunisie): murghabien (dolomies inférieures et marnes du chabet n guer); pl. 4, fig. 14(a).djebel tebaga (tunisie): murghabien 1977 mizzia.wray, fig. 103.texas (états-unis d’amérique): permien 1978 mizzia velebitana.anelkoviê, pl. xl, fig. 7 = pl. xlvii, fig. 4, extrait de kochansky & herak (1960: pl. v, fig. 1); pl. xl, fig. 8 = pl. xlvii, fig. 5, extrait de kochansky & herak (1960: pl. v, fig. 12); pl. xlvii, fig. 6, extrait de kochansky & herak (1960: pl. v, fig. 6); pl. lii, fig. 1, extrait de simiê (1933: pl. ix, fig. 1) 1978 mizzia.e. flügel, pl. 30, fig. 9.velebit mt (croatie): permien “moyen” 1978 mizzia velebitana.kulik, pl. viii, fig. 1-2.shakhtau massif, bashkirskaya (fédération de russie): sakmarien, tastubien (zone à pseudofusulina moelleri, sous-zone ts1) 1978a mizzia velebitana.mamet & roux, pl. 1, fig. 3, extrait de girty (1908: pl. 5, fig. 9); pl. 1, fig. 4, extrait de girty (1908: pl. 5, fig. 8); pl. 1, fig. 5-7.el capitan, guadalupe mts, texas (états-unis d’amérique): guadalupien (capitan limestone); pl. 1, fig. 8.s delaware mts, texas (états-unis d’amérique): permien (delaware mt fm); pl. 1, fig. 9, extrait de h. termier et al. (1977: pl. 3, fig. 3) 1978 m i z z i a.scholle, p. 9 bas.new mexico (états-unis d’amérique): guadalupien (capitan limestone tansill fm transition) 1978 mizzia velebitana.zaninetti et al., pl. 84, fig. 1-7, 9 & 11-14; pl. 87, fig. 11 pars.kuh-e gahkum, s zagros (iran): permien “supérieur” 1979 mizzia velebitana.d.t. nguyên, pl. 12, fig. 4 pars; pl. 32, fig. 20.b.cham lang kuy, se battambang (cambodge): permien; pl. 30, fig. 1-4.sisophon (cambodge): permien supérieur (zone à y a b e i n a e t lepidolina) 1980 mizzia velebitana.lys in lys et al., pl. 1, fig. 2-3.lamayuru, ladakh (inde): djulfien (zone à coloniella parva ) 1980 mizzia velebitana.vachard, pl. 4, fig. 4.m.tangui jamal, tezak (afghanistan): murghabien moyensupérieur; pl. 4, fig. 5 pars.tezak khwaja bahadur, tezak (afghanistan): kubergandien; pl. 4, fig. 7.m.behsud, tezak (afghanistan): djulfien; pl. 23, fig. 12 pars.tezak khwaja bahadur, tezak (afghanistan): murghabien supérieur; pl. 24, fig. 1.tezak khwaja bahadur, tezak (afghanistan): murghabien inférieur 106 geologia croatica 53/1 1981 mizzia.ercegovac, extrait de wray (1977: fig. 103) 1981 mizzia velebitana.mu, pl. iv, fig. 10-11.w guizhou (chine populaire): permien “supérieur” 1981 mizzia velebitana.nakamura, pl. 10, fig. 4.ishiyama, o _ n o c hō tanigumi-mura, gifu-ken, honshū (japon): permien (ishiyama limestone) 1981 mizzia velebitana.vachard in vachard & montenat, pl. 6, fig. 1, extrait de vachard (1980: pl. 23, fig. 12) 1982 mizzia velebitana.mu, pl. viii, fig. 3-5 & 9.xizang / tibet (chine populaire): permien “inférieur” / partie supérieure 1983 mizzia velebitana.jenny-deshusses, pl. 16, fig. 3; pl. 17, fig. 1.kuh e jamal, tabas, e téhéran (iran): murghabien moyen (jamal fm) 1984 mizzia velebitana.e. flügel, kochansky-devidé & ramovπ, pl. 29, fig. 5.straæa, bled (slovénie): permien “moyen” 1984 (?) mizzia sp.e. flügel, kochansky-devidé & ramovπ, pl. 29, fig. 4.straæa, bled (slovénie): permien “moyen” 1984 mizzia velebitana.nakamura & chisaka, pl. 6, fig. 3-4.mt atagoyama, chôshi-shi, chiba-ken, honshū (japon): permien “supérieur” (takagami conglomerate) 1985 mizzia velebitana.vachard, pl. 1, fig. 3 & 10.djebel tebaga (tunisie): murghabien supérieur; pl. 3, fig. 3.djebel tebaga (tunisie): murghabien supérieur; pl. 3, fig. 4.djebel tebaga (tunisie): murghabien supérieur; pl. 3, fig. 6 pars.djebel tebaga (tunisie): murghabien supérieur 1986 mizzia velebitana.fontaine et al., pl. 24, fig. 1-4.botulan island, calamian islands (philippines): murghabien supérieur midien 1986 macroporella sp.kalantari, fig. 86.1-3; pl. 33, fig. 1-2.kuh-e naiband (iran): permien “supérieur” (jamal fm) 1986 pseudovermiporella sodalica .kalantari, fig. 86.4-9; pl. 33, fig. 1.naiband (iran): permien “supérieur” 1986 mizzia velebitana.mirkoviê, pl. xi, fig. 4.2.bjeloπevina, monténégro (yougoslavie): permien supérieur (bellerophon limestone); pl. xii, fig. 2 pars.vasiljeviêi, nikπiêka æupa, monténégro (yougoslavie): permien supérieur (bellerophon limestone) 1986a mizzia velebitana.d.t. nguyên, pl. 9, fig. 3-4.sisophon (cambodge): murghabien supérieur midien 1986b mizzia velebitana.d.t. nguyên, pl. 15, fig. 2.guguk bulat, padang, sumatra (indonésie): permien 1987 mizzia velebitana.noé, pl. 22, fig. 3 pars.oberkovel, nw ampezzo, friuli venezia giulia (italie): permien supérieur (bellerophon fm / partie moyenne); pl. 29, fig. 3.mte ruche, nw ampezzo, friuli venezia giulia (italie): permien supérieur (bellerophon fm / partie supérieure) 1988 mizzia velebitana.broglio loriga et al., pl. 3, fig. 1.sass de pútia / peitler kofel, val badia / gadertal, trentino alto adige (italie): permien supérieur (bellerophon fm) 1988 mizzia velebitana.e. flügel & kahler, pl. 19, fig. 3.ne karaputar dag, belemedik, nigde (turquie): permien moyen 1988a mizzia velebitana.haas et al., pl. 2, fig. 2.forage gárdony 1 (ga-1), e székesfehérvár, fejér (hongrie): permien “supérieur” (alcsutdoboz limestone fm) 1988b mizzia velebitana.lys, pl. xv, fig. 2-3, extrait de lys et al. (1980: pl. 1, fig. 2-3) 1988 mizzia velebitana.sartorio & venturini, p. 38, haut.velebit mt (croatie): permien “supérieur”; p. 38, bas.djebel tebaga (tunisie): permien “supérieur” 1988 dasycladales.sartorio & venturini, p. 218 [= p. 38, haut] 1989 mizzia velebitana.kyölüoglu & altiner, pl. ii, fig. 4.hakkâri (turquie): permien supérieur 1989 mizzia velebitana.d.t. nguyên, pl. 34, fig. 1-2.guguk bulat, sumatra (indonésie): murghabien 1989 mizzia velebitana.vachard, pl. 6, fig. 2 pars; pl. 7, fig. 2; pl. 9, fig. 4.pulau apat, jambi province, sumatra (indonésie): assélien moyen-sakmarien (assélien supérieur probable) 1990 mizzia velebitana.e. flügel, pl. 1, fig. 1.jazi pinari / yazi pinar, ala dag, w konya (turquie): permien “moyen” / partie supérieure; pl. 1, fig. 2-3.w koca-dag, n bergama (turquie): murghabien moyen (zone à neoschwagerina craticulifera ) 1990 m i z z i a (? mizzia velebitana).kirkland & chapman, fig. 5 & 8.dark canyon, guadalupe mts, new mexico (états-unis d’amérique): guadalupien; fig. 6.walnut canyon, guadalupe mts, new mexico (états-unis d’amérique): guadalupien; fig. 10.guadalupe mts, new mexico (états-unis d’amérique): guadalupien 107granier & grgasoviê: les algues dasycladales du permien et du trias... 1991 mizzia velebitana.e. flügel et al., pl. 47, fig. 2.e pietra di salomone, sw palazzo adriano, sw prizzi, sicile (italie): murghabien (calcaire à neoschwagerina) 1991 m i z z i a.riding & guo, fig. 9.guadalupe mts, new mexico (états-unis d’amérique): guadalupien (capitan fm) 1991 mizzia velebitana.sremac, pl. 7, fig. 1 pars & 2 pars.milaπnovac, bruπane, baπke oπtarije, velebit mt (croatie): murghabien (zone à neoschwagerina craticulifera ) 1991 (?) mizzia velebitana ?.sremac, pl. 6, fig. 2 pars.milaπnovac, bruπane, baπke oπtarije, velebit mt (croatie): murghabien (zone à neoschwagerina craticulifera ) 1992 mizzia velebitana.okla, pl. 45, fig. 7-10.unayzah, quassim district (arabie saoudite): djulfien (khuff fm, midhnab member) 1992 mizzia velebitana.vachard et al., pl. iii, fig. 3 pars.s doi luang mts, nw thaïlande (thaïlande): bolorien 1993 mizzia sp.dawson, pl. 9, fig. 9-10.n sara buri, n krung thep / bangkok (thaïlande): sakmarienyahtashien (rat buri limestone) 1993 mizzia velebitana.vachard & razgallah, pl. 1, fig. 3.1 & 4.1.djebel tebaga (tunisie): murghabien supérieur (zone à neoschwagerina, yabeina et dunbarula , sous-zone à dunbarula nana ); pl. 2, fig. 5.2.djebel seïkra, djebel tebaga (tunisie): murghabien supérieur (zone à neoschwagerina, yabeina et dun barula , sous-zone à dunbarula mathieui et codonofusiella); pl. 3, fig. 7 pars.forage kirchaou, s gabes (tunisie): murghabien supérieur (zone à neoschwagerina, yabeina et dunbarula ) 1993 mizzia velebitana.weidlich et al., pl. 32, fig. 4.ba’id (oman): permien “supérieur” 1994 (?) mizzia cf. m. velebitana.okla, pl. 2, fig. 3-8.e unayzah, quassim district, riyadh (arabie saoudite): djulfien (khuff fm, midhnab member) 1995 m i z z i a v e l e b i t a n a.kirkland, pl. 1, fig. 4.walnut canyon, guadalupe mts, new mexico (états-unis d’amérique): kazanien (carlsbad group, tansill fm); pl. 1, fig. 6.mc kittrick canyon, guadalupe mts, texas (états-unis d’amérique): kazanien (carlsbad group, tansill fm) 1995 mizzia velebitana.vachard et al., pl. 55, fig. 15.fodélé, iráklion, kriti (grèce): murghabien supérieur (zone à neoschwagerina margaritae ) 1997 m i z z i a v e l e b i t a n a .de castro, pl. 3, fig. 1-4; pl. 17, fig. 1-2.nikπiêka æupa, monténégro (yougoslavie): permien; pl. 3, fig. 5.bruπane, velebit mt (croatie): permien 1997 mizzia velebitana.pantiê-prodanoviê, pl. i, fig. 2.dvorska, n krupanj, nw serbie (yougoslavie): permien supérieur mizzia yabei (karpinsky 1909) pia 1920 [= stolleyella yabei karpinsky 1909 ] 1909a stolleyella yabei n. sp.karpinsky, fig. dans le texte, p. 1055.kinshō -zan hill, mino-akasaka, n o _ gaki-shi, gifu-ken, honshū (japon): permien (s c h w a g e r i n a l i m e s t o n e ).type: fig. dans le texte, p. 1055, coll. a. karpinsky 1909b stolleyella yabei n. sp.karpinsky, fig. dans le texte, p. 268, extrait de karpinsky (1909a: fig. dans le texte, p. 1055) 1920 mizzia c f . yabei n. comb.pia, pl. i, fig. 4-6.paklenica, velebit mt (croatie): “carbonifère supérieur” (dolomie à mizzia) 1927 non mizzia yabei [= atractyliopsis lastensis].ogilvie gordon, pl. ix, fig. 10; pl. xiii, fig. 6 pars 1942 mizzia yabei.johnson & dorr, pl. 10, fig. 1 & 6.walnut canyon, guadalupe mts, new mexico (étatsunis d’amérique): guadalupien; pl. 12, fig. 1-2.guadalupe mts, new mexico (états-unis d’amérique): guadalupien 1942 m i z z i a.johnson & dorr, pl. 12, fig. 3.guadalupe mts, new mexico (états-unis d’amérique): guadalupien 1942 mizzia yabei.johnson, pl. 3, fig. 4, extrait de johnson & dorr (1942: pl. 12, fig. 3, détail); pl. 3, fig. 6, extrait de johnson & dorr (1942: pl. 10, fig. 6); pl. 7, fig. 2, extrait de johnson & dorr (1942: pl. 12, fig. 3) 1944 mizzia yabei.johnson, pl. 302, fig. 2, extrait de johnson & dorr (1942: pl. 10, fig. 6) 1952c mizzia yabei.endo, pl. 23, fig. 2-5.mt kurohime, nishikubiki-gun, niigata-ken, honshū (japon): permien “moyen” 108 geologia croatica 53/1 1954 mizzia yabei.endo in endo & kanuma, pl. xv, fig. 1.asagara, aioi-mura, gujō-gun, gifu-ken, hons hū (japon): permien inférieur (shimadani fm, zone à p s e u d o f u s u l i n a); pl. xv, fig. 2.hachimanmachi, gujō-gun, gifu-ken, honshū (japon): permien inférieur (shimadani fm, zone à pseudofusulina); pl. xv, fig. 3.iritsu, nishiwara-mura, gujō-gun, gifu-ken, honshū (japon): permien inférieur-moyen (kuchibora fm, zone à pseudofusulina zone à parafusulina ) 1954 mizzia.johnson, pl. 35, fig. 2, extrait de johnson & dorr (1942: pl. 12, fig. 3); pl. 36, extrait de johnson & dorr (1942: pl. 12, fig. 3) 1954b mizzia yabei.konishi, pl. ii, fig. 16.kosaki, shimomatsukoma-mura, yatsushiro-gun, kumamota-ken, kyūshū (japon): permien moyen (kosaki fm, zone à neoschwagerina-verbeeckina) 1956 m i z z i a y a b e i.endo, pl. 23, fig. 5.shōm u r a tōge pass, agano-mura, hannō-shi, iruma-gun, saitamaken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne) 1956 mizzia velebitana.jones, fig. 4.6, extrait de johnson & dorr (1942: pl. 12, fig. 3) 1958 (?) mizzia yabei ?.kiss, pl. i, fig. 3 pars.sirok, mátra hegység, heves (hongrie): permien “supérieur” 1959 mizzia yabei.bilgütay, pl. ii, fig. 3-4.hazro, diyarbakir (turquie): permien “supérieur” 1960 mizzia yabei.kochansky & herak, pl. v, fig. 7-8.bruπane, velebit mt (croatie): permien “moyen”; pl. vi, fig. 1, 3-4 & 7.zvonik, sw raduë, sv. rok, lika (croatie): permien “moyen”; pl. vi, fig. 2.limljani, bar, s monténégro (yougoslavie): permien “moyen”; pl. vi, fig. 5-6.»itluk, s veliki beπlinac, velebit mt (croatie): permien “moyen” 1961b mizzia yabei.endo, pl. 4, fig. 4-5.sukawa, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 4, fig. 6.w hongō, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm) 1961c m i z z i a y a b e i.endo, pl. 4, fig. 2.chōjagamori, kuroiwa, kyowa, shuhōc hō, ne mine-shi, yamaguchi-ken, honshū (japon): permien inférieur (akiyoshi limestone group, zone à pseudoschwagerina , sous-zone à triticites simplex) 1961 (?) mizzia yabei ?.hanzawa, pl. lxix, fig. 2 pars.okubo, akasaka-chō, fuha-gun, gifu-ken, honshū (japon): permien supérieur, ‘basleo’ (akasaka limestone, zone à yabeina) 1961 mizzia.johnson, pl. 46, fig. 2, extrait de johnson & dorr (1942: pl. 12, fig. 3 détail) 1962 (?) m i z z i a ? cf. y a b e i [= ? gyroporella tenuimarginata ].kochansky-devidé & milanoviê, pl. vi, fig. 6.krπ, s mojkovac, rivière tara, monténégro (yougoslavie): sakmarien supérieur artinskien inférieur 1963 mizzia yabei.herak, fig. 30 (en bas, à gauche), extrait de kochansky & herak (1960: pl. vi, fig. 6) 1963 m i z z i a y a b e i.johnson, pl. 61, fig. 2, extrait de johnson & dorr (1942: pl. 12, fig. 3); pl. 63, fig. 2, extrait de johnson & dorr (1942: pl. 10, fig. 6); pl. 63, fig. 3, extrait de johnson & dorr (1942: pl. 12, fig. 3) 1963 mizzia cf. m. yabei.johnson, pl. 63, fig. 4, extrait de pia (1920: pl. i, fig. 6); pl. 63, fig. 5, extrait de pia (1920: pl. i, fig. 4); pl. 63, fig. 6, extrait de pia (1920: pl. i, fig. 5) 1964 mizzia yabei[s i c].glintzboeckel & rabaté, pl. lxxiv, fig. 2 pars; pl. lxxxvi, fig. 2 pars.djebel tebaga (tunisie): permien supérieur (zone à yabeina) 1969 mizzia yabei.endo, pl. x, fig. 1-3.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina zone à neoschwageri na simplex / partie inférieure) 1970a m i z z i a y a b e i.kochansky-devidé, pl. xxiii, fig. 5-6.w karavanke (slovénie): permien inférieur (trogkofelkalk) 1971 m i z z i a.horowitz & potter, pl. 60, fig. 2.eddy county, guadalupe mts, new mexico (états-unis d’amérique): guadalupien (tansill fm) 1971 m i z z i a y a b e i.ishijima et al., pl. 3, fig. 1, 2.a-b & 3.sakaishimachibun, agano-mura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur” 1972 m i z z i a y a b e i.homann, pl. 6, fig. 49-50.untere treßdorfer alm, n treßdorfer höhe, kärnten (autriche): sakmarien (treßdorfer kalk) 1977 mizzia yabei.vachard in h. termier et al., pl. 4, fig. 14(e).djebel tebaga (tunisie): murghabien 1978 m i z z i a y a b e i.anelkoviê, pl. xxxix, fig. 7, extrait de kochansky-devidé (1970a: pl. xxiii, fig. 5); pl. xxxix, fig. 9, extrait de kochansky-devidé (1970a: pl. xxiii, fig. 6); pl. xl, fig. 5, extrait de 109granier & grgasoviê: les algues dasycladales du permien et du trias... kochansky & herak (1960: pl. vi, fig. 7); pl. xl, fig. 6, extrait de kochansky & herak (1960: pl. v, fig. 8); pl. xlvii, fig. 7-8, extrait de kochansky & herak (1960: pl. vi, fig. 6-7); pl. xlvii, fig. 9, extrait de kochansky & herak (1960: pl. v, fig. 7) 1981 mizzia yabei.nakamura, pl. 7, fig. 1-2.ishiyama, o _ n o c hō tanigumi-mura, gifu-ken, honshū (japon): permien (ishiyama limestone) 1981 m i z z i a y a b e i.ramovπ & kochansky-devidé, pl. 1, fig. 1.s tof, gozd-martuljek kranjska gora (slovénie): permien inférieur (trogkofelkalk) 1984 mizzia yabei.nakamura & chisaka, pl. 6, fig. 5-7.mt atagoyama, chōshi-shi, chiba-ken, honshū (japon): permien “supérieur” (takagami conglomerate) 1985 mizzia yabei [= eogoniolina johnsoni].vachard, pl. 1, fig. 1.djebel tebaga (tunisie): murghabien supérieur 1990 mizzia yabei.dragastan et al., pl. i, fig. 2-3.sakesar, salt range (pakistan): murghabien supérieur djulfien supérieur (wargal fm) 1990 mizzia yabei.e. flügel, pl. 4, fig. 6.balya, wnw balikesir (turquie): murghabien supérieur (zone à neoschwagerina / partie supérieure) 1992 mizzia yabei.vachard et al., pl. iii, fig. 5 pars.s doi luang mts, nw thaïlande (thaïlande): bolorien 1993 mizzia yabei.vachard & razgallah, pl. 1, fig. 1.1, 3.2, 5 pars & 6 pars.djebel tebaga (tunisie): murghabien supérieur (zone à neoschwagerina, yabeina et dunbarula , sous-zone à dunbarula nana ) 1993 mizzia yabei.vachard et al., pl. i, fig. 3; pl. ii, fig. 6 pars.s ermióni, argolís (grèce): djulfien (galet dans une “coulée boueuse” kimméridgienne de la fm de potami) 1995 m i z z i a y a b e i.kirkland, pl. 1, fig. 5.walnut canyon, guadalupe mts, new mexico (états-unis d’amérique): kazanien (carlsbad group, tansill fm) 1996 mizzia.wendt, fig. 2.jushui, anxian county, sichuan (chine populaire): guadalupien, ‘maokouan’ 1996 m i z z i a y a b e i.wendt, fig. 3, 5.a-f & 6.a-f.jushui, anxian county, sichuan (chine populaire): guadalupien, ‘maokouan’ 1997 mizzia yabei.pantiê-prodanoviê, pl. i, fig. 3.dvorska, n krupanj, nw serbie (yougoslavie): permien supérieur 1997 m i z z i a y a b e i.vachard & fourcade, fig. 12.17 & 12.27-28.finca santa maria, presa de chixoy, alta verapaz (guatemala): léonardien moyen (fm chócal, chócal de purulhà); fig. 12.36.suquinay, purulhà, baja verapaz (guatemala): bolorien (fm chócal, chócal de suquinay) nanjinoporella mu et elliott 1982 *nanjinoporella pagoda mu et elliott 1982 1982 nanjinoporella pagoda n. gen. n. sp.mu & elliott, fig. 3-6.dawa, chihsia shan hill, nanjing (chine populaire): artinskien (chishia fm, swine limestone member).holotype: fig. 3-6, lame mince n° pb. 68055, échantillon n d 501-h 12-5, collection x.-n. mu, nanjing institute of geology and paleontology, academia sinica, nanjing (chine populaire) neodasyporella endo 1969 [? synonyme postérieur de anthracoporella pia 1920, d’après bassoullet et al., 1979] *neodasyporella innerannulata endo 1969 1969 neodasyporella innerannulata n. gen. n. sp.endo, pl. xxxvi, fig. 1-2; pl. xlii, fig. 6.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien inférieur-moyen (rat buri limestone, zone à misellina zone à neoschwagerina simplex).holotype: pl. xxxvi, fig. 12, lame mince n° gk.d 13750, kyūshū university, fukuoka (japon) 110 geologia croatica 53/1 neoteutloporella bassoullet et al. 1978, emend. de castro 1993 neoteutloporella rajkae parente et climaco 1999 1999 neoteutloporella rajkae n. sp.parente & climaco, pl. 34, fig. 1-8; pl. 35, fig. 1-8.mte rotonda, e maratea, basilicata (italie): trias supérieur (norien).holotype: pl. 34, fig. 1 & 3, lame mince n° ac572.7; isotypes: pl. 34, fig. 2 & 4, lame mince n° ac554.23; pl. 34, fig. 5, lame mince n° ac354.21; pl. 34, fig. 6, lame mince n° ac561.2; pl. 34, fig. 7, lame mince n° ac561.6; pl. 34, fig. 8, lame mince n° ac560; pl. 35, fig. 1, lame mince n° ac559.1; pl. 35, fig. 2, lame mince n° ac554.22; pl. 35, fig. 3, lame mince n° ac561.1; pl. 35, fig. 4, lame mince n° ac554.23; pl. 35, fig. 5, lame mince n° ac562.2; pl. 35, fig. 6, lame mince n° ac565.12; pl. 35, fig. 7, lame mince n° ac554.20; pl. 35, fig. 8, lame mince n° ac565.1, collection v. zamparelli, dipartimento di scienze della terra, università di napoli “federico ii” (italie) neoteutloporella triasina (schauroth 1859) bassoullet et al. 1978 [cf. euteutloporella triasina (schauroth 1859) de castro 1993 ] nipponophysoporella endo 1959, nom. nud. [synonyme postérieur de mizzia schubert 1909, emend. rezak 1959, d’après vachard, 1980 ] *nipponophysoporella elegans endo 1959, nom. nud. 1 9 5 9 (nom. nud.) nipponophysoporella elegans n. gen. n. sp.endo, pl. 36, fig. 5-6; pl. 37, fig. 1-2.otani, horadani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honsh ū (japon): permien inférieur (o _ zu fm, zone à p s e u d o f u s u l i n a); pl. 36, fig. 7.sotedani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū ( j a p o n ) : permien moyen (o _ zu fm, zone à n e o s c h w a g e r i n a / partie inférieure).“holotype” (syntypes): pl. 36, fig. 6, lame mince n° 21049; pl. 37, fig. 2, lame mince n° 21129b, geol. min. inst., tokyo kyoiku daigaku [tokyo university of education ] (japon) 1961a (nom. nud.) nipponophysoporella elegans.endo, pl. 4, fig. 4, extrait de endo (1959: pl. 37, fig. 1) 1 9 6 1 b (?) (nom. nud.) nipponophysoporella cf. e l e g a n s.endo, pl. 13, fig. 9.w nagaoka, santō-machi, sakatagun, shiga-ken, honshū (japon): permien inférieur (samegai fm) 1 9 6 3 (nom. nud.) nipponophycus elegans [s i c].johnson, pl. 65, fig. 1, extrait de endo (1959: pl. 36, fig. 5); pl. 65, fig. 2, extrait de endo (1959: pl. 36, fig. 7); pl. 65, fig. 3, extrait de endo (1959: pl. 37, fig. 1); pl. 65, fig. 4, extrait de endo (1959: pl. 36, fig. 6); pl. 65, fig. 5, extrait de endo (1959: pl. 37, fig. 5) 1 9 7 1 (?) (nom. nud.) nipponophysoporella cf. e l e g a n s.ishijima et al., pl. 15, fig. 3.sakaishimachibun, aganomura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur” 1988 (nom. nud.) nipponophysoporella elegans .deloffre, pl. 8, fig. 1, extrait de endo (1959: pl. 36, fig. 5); pl. 8, fig. 2, extrait de endo (1959: pl. 36, fig. 7) oligoporella pia 1912 oligoporella cauliculus endo 1961 1961b oligoporella cauliculus n. sp.endo, pl. 8, fig. 4.e o _ nogi, santō-machi, sakata-gun, shiga-ken, h o n s hū (japon): permien “moyen” / partie inférieure (o _ nogi fm).holotype: pl. 8, fig. 4, lame mince n° 510529-12, geological survey of japan (japon) oligoporella chia herak 1967 1967a oligoporella chia n. sp.herak, pl. 7, fig. 5-7; pl. 8, fig. 1-3.ligaridi, khíos / chios (grèce): ladinien.holotype: pl. 7, fig. 7, lame mince n° t359.c, collection k.-w. tietze, geologisch-paläontologischen institut der universität marburg (allemagne) 1967a (?) oligoporella cf. chia.herak, pl. 8, fig. 4.ligaridi, khíos / chios (grèce): ladinien 1972b oligoporella chia .ott, pl. ii.nohutalan, karaburun, nw izmir (turquie): ladinien supérieur 1973 (?) oligoporella chia .popa & dragastan, pl. xix, fig. 75.dealul ruget remeţi, w valea boiului, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien-ladinien, illyrien supérieur langobardien 111granier & grgasoviê: les algues dasycladales du permien et du trias... 1973 (?) physoporella lotharingica .popa & dragastan, pl. xix, fig. 77.dealul ruget remeţi, w valea boiului, e p ǎdurea craiului, apuseni mts, bihor (roumanie): anisien-ladinien, illyrien supérieur langobardien 1980 (?) oligoporella chia .dragastan, pl. v, fig. 5, extrait de popa & dragastan (1973: pl. xix, fig. 77); pl. vi, fig. 14.glimeia, pǎdurea craiului, apuseni mts, bihor (roumanie): carnien oligoporella duplicata pia 1920 [cf. poikiloporella duplicata (pia 1920) 1943] oligoporella elegans assmann ex pia 1931 [= diplopora elegans assmann 1926, nom. nud. ] 1 9 2 6 (nom. nud.) diplopora elegans n. sp.assmann, p. 505-506, non figurée.s tarnowskie góry / tarnowitz, haute silésie (pologne): trias (diploporendolomiten).type non figuré 1931 oligoporella elegans n. comb.pia, pl. xxi, fig. 3-6.nowe koszyce / neu-koschütz, nw strzelce opolskie, haute silésie (pologne): anisien, ou d’après kotański (1986): anisien, illyrien.validation de l’espèce; types: pl. xxi, fig. 3-6, lame mince n° ?, collection j. von pia, naturhistorisches museum, wien (autriche) 1938 oligoporella elegans .schmidt, fig. 8.b, extrait de pia (1931: pl. xxi, fig. 3) 1986 oligoporella elegans .kotański, pl. cv, fig. 22, extrait de pia (1931: pl. xxi, fig. 4); pl. cv, fig. 23, extrait de pia (1931: pl. xxi, fig. 3); pl. cv, fig. 24-25, extrait de pia (1931: pl. xxi, fig. 5-6) oligoporella elegans endo 1969, nom. nud. [illégitime car c’est un homonyme postérieur de oligoporella elegans assmann ex pia 1931 ] 1969 (nom. nud.) oligoporella elegans n. sp.endo, pl. xxxiv, fig. 1-5.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancel l i n a ).holotype: pl. xxxiv, fig. 1, lame mince n° gk.d 13077, kyū s hū university, fukuoka (japon) 1990 (nom. nud.) oligoporella elegans .e. flügel, pl. 3, fig. 1 pars.e balya, wnw balikesir (turquie): permien oligoporella expansa endo 1959, nom. nud. 1 9 5 9 (nom. nud.) oligoporella expansa n. sp.endo, pl. 34, fig. 6-8.hatahoko, nyūgawa-mura, o _ no-gun, gifuken, honshū (japon): permien inférieur (gonbō fm, zone à p a r a f u s u l i n a = zone à p s e u d o f u s u l i n a). “holotype” (syntypes): pl. 34, fig. 6 et/ou 8, lame mince n° 31132b; pl. 34, fig. 7, lame mince n° 21133, geol. min. inst., tokyo kyoiku daigaku [tokyo university of education ] (japon) 1 9 6 6 (nom. nud.) oligoporella expansa .johnson & danner, pl. 55, fig. 6.san juan county, nw washington (états-unis d’amérique): permien (stillaguamish group); pl. 55, fig. 7.snohomish county, nw washington (états-unis d’amérique): permien (stillaguamish group); pl. 55, fig. 8.e jesmond, nw porcupine creek, british columbia (états-unis d’amérique): permien “supérieur” (cache creek group, marble canyon fm) oligoporella hidaensis endo in endo et kanuma 1954 1954 oligoporella hidaensis n. sp.endo in endo & kanuma, pl. xv, fig. 4.s otohime fall, hachimanmachi, gujō-gun, gifu-ken, honshū (japon): permien inférieur (shimadani fm, zone à pseudofusulina); pl. xv, fig. 5.suwara-mura, gujō-gun, gifu-ken, honshū (japon): permien inférieur (shimadani fm, zone à p s e u d o f u s u l i n a); pl. xv, fig. 6.shimadani valley, hachiman-machi, gujō -gun, gifu-ken, honshū (japon): permien inférieur (shimadani fm, zone à pseudofusulina).syntypes: pl. xv, fig. 4-6, lames minces n° 193-195, department of earth sciences, saitama university, urawa (japon) oligoporella himurensis ishijima et al. 1971 1971 oligoporella himurensis n. sp.ishijima et al., pl. 7, fig. 5; pl. 12, fig. 1.a.sakaishimachibun, aganomura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur”.holotype: pl. 12, fig. 1.a, spécimen n° nsmp1-18095a, national science museum, tokyo (japon) 112 geologia croatica 53/1 oligoporella horiguchii endo 1957 1957 oligoporella horiguchii n. sp.endo, pl. 40, fig. 1-4.zenbutsuji-dani, taishaku-mura, hiba-gun, hiroshima-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie supérieure).syntypes: pl. 40, fig. 1-4, lame mince n° 564, department of earth sciences, saitama university, urawa (japon) 1959 oligoporella horiguchii .endo, pl. 33, fig. 8.gonbō, tochiyamadani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien supérieur (o _ zu fm, zone à yabeina); pl. 34, fig. 9.otani, horadani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien inférieur (o _ zu fm, zone à pseudo f u s u l i n a); pl. 35, fig. 8.chōshidani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien (o _ zu fm / partie inférieure) 1963 oligoporella horiguchii .johnson, pl. 66, fig. 9, extrait de endo (1957: pl. 40, fig. 4); pl. 66, fig. 10, extrait de endo (1957: pl. 40, fig. 3); pl. 66, fig. 11, extrait de endo (1957: pl. 40, fig. 2) oligoporella isomii endo 1961 1961b oligoporella isomii n. sp.endo, pl. 12, fig. 11.manganji, sant ō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm).holotype: pl. 12, fig. 11, lame mince n° 510606-b, geolog ical survey of japan (japon) oligoporella karrerioidea pia 1935 1935a oligoporella karrerioidea n. sp.pia, pl. iii, fig. 1-3.n haliluêi, e sarajevo (bosnie-herzégovine): anisien, pelsonien.type: pl. iii, fig. 3, lame mince n° 575b (1), collection j. von pia, naturhistorisches museum, wien (autriche) oligoporella nipponica endo 1956 1956 oligoporella nipponica n. sp.endo, pl. 24, fig. 10.shōm u r a tōge pass, agano-mura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne); pl. 24, fig. 11.shimokuzū, agano-mura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne); pl. 24, fig. 12; pl. 25, fig. 1.shōw a d e n kō f a c t o r y , kagemori-mura, chichibu-gun, saitama-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne); pl. 25, fig. 2.hinoda, chichibu-shi, saitama-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne).“holotypes” (syntypes): pl. 24, fig. 12, lame mince n° 223; pl. 25, fig. 1, lame mince n° 234, department of earth sciences, saitama university, urawa (japon) 1963 oligoporella nipponica .johnson, pl. 66, fig. 1, extrait de endo (1956: pl. 24, fig. 12); pl. 66, fig. 2, extrait de endo (1956: pl. 25, fig. 2); pl. 66, fig. 3, extrait de endo (1956: pl. 25, fig. 1); pl. 66, fig. 4, extrait de endo (1956: pl. 24, fig. 10) oligoporella omiensis endo 1952 1952c oligoporella omiensis n. sp.endo, pl. 23, fig. 8.utatonami, nishikubiki-gun, niigata-ken, honshū (japon): permien “inférieur”.“syntypes” (holotype): pl. 23, fig. 8, lame mince n° 121, department of earth sciences, saitama university, urawa (japon) *oligoporella pilosa pia 1912 oligoporella pilosa var . balinensis raciborski ex pastwa-leszczyn ´ ska et śliwiń ski 1960 [= gyroporella balinensis raciborski 1892, nom. nud. ] 1892 (nom. nud.) gyroporella balinensis n. sp.raciborski, p. 7-8, non figurée.type non figuré 1960 oligoporella pilosa forma balinensis n. stat.pastwa-leszczyńska & śl i w iński, fig. 9; pl. iii, fig. 14 [= fig. 9].ka̧ty (rosowa góra), nw chrzanów, haute silésie (pologne): anisien.validation de la var iété; type (?): fig. 9 = pl. iii, fig. 14, katedrze zlóz̊ rud na agh w krakowie, kraków (pologne) oligoporella pilosa var . intusannulata pia 1935 1935a oligoporella pilosa var. i n t u s a n n u l a t a n. var.pia, fig. 16.w trebeviê, s sarajevo (bosnie-herzégovine): anisien, hydaspien supérieur pelsonien; fig. 17-18.n haliluêi, e sarajevo (bosnie-herzé113granier & grgasoviê: les algues dasycladales du permien et du trias... govine): anisien, pelsonien; fig. 19.ograda, areæin brijeg grab, bosansko grahovo (bosnie-herzégovine): anisien, ? hydaspien .4 des 5 types: fig. 16, lame mince n° 557a/1; fig. 17, lame mince n° 575a/4; fig. 18, lame mince n° 575a/6; fig. 19, lame mince n° 235a/5, collection j. von pia, naturhistorisches museum, wien (autriche) 1935a non oligoporella pilosa var. intusannulata n. var.pia, pl. ii, fig. 8.n haliluêi, e sarajevo (bosnie-herzégovine): anisien, pelsonien.1 des 5 types: pl. ii, fig. 8, lame mince n° 576b, collection j. von pia, naturhistorisches museum, wien (autriche) 1940b oligoporella pilosa i n t u s a n n u l a t a .pia, pl., fig. 7.silická brezová, slovenský kras (slovaquie): anisien, pelsonien 1954 oligoporella pilosa forma intusannulata [sic].lemoine in fallot & solé sabaris, pl. v, fig. 3.s picon de gor, sierra de baza, s baza, e granada (espagne): anisien 1957 oligoporella pilosa i n t u s a n n u l a t a .bystrický, pl. iv, fig. 3-5.silická brezová, slovenský kras (slovaquie): anisien, pelsonien; pl. iv, fig. 6.silická planina, slovenský kras (slovaquie): anisien, pelsonien 1964 oligoporella pilosa var. intusannulata .bystrický, pl. x, fig. 1, 5 & 8; pl. xi, fig. 3 & 7; pl. xii, fig. 1 & 3; pl. xxxiv, fig. 1.silická brezová, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur; pl. x, fig. 3 & 9; pl. xi, fig. 1 & 5; pl. xii, fig. 2.pleπivecká planina, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur 1964 (?) oligoporella pilosa var. ind.bystrický, pl. x, fig. 7.silická brezová, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur 1965 oligoporella pilosa var. pilosa.assereto et al., pl. 78.a & pars; pl. 81, fig. 2.w castelfranco, val gola / val camónica, ne bergamo, lombardia (italie): anisien (calcare di camorelli) 1965 oligoporella pilosa var. i n t u s a n n u l a t a .assereto et al., pl. 78.b; pl. 79, fig. 2-4.w castelfranco, val gola / val camónica, ne bergamo, lombardia (italie): anisien (calcare di camorelli) 1965 oligoporella pilosa var. v a r i c a n s .assereto et al., pl. 79, fig. 1; pl. 81, fig. 6-7.w castelfranco, val gola / val camónica, ne bergamo, lombardia (italie): anisien (calcare di camorelli) 1965 oligoporella pilosa var. i n t u s a n n u l a t a .herak, pl. xi, fig. 5 & 7.wsw klanac pucaloviêa, sv. rok, lika (croatie): anisien 1965 oligoporella pilosa var. i n t u s s a n n u l a t a [s i c].schalekova, pl. xxxvi, fig. 1.n silická brezová, slovenský kras (slovaquie): anisien, pelsonien 1966 oligoporella pilosa var. i n t u s a n n u l a t a .bystrický, pl. vi, fig. 2.ponická lehôtka poniky oravce postredná môlëa, e banská bystrica (slovaquie): anisien, pelsonien (gutensteiner kalk); pl. vi, fig. 3.ponická lehôtka poniky oravce postredná môlëa, e banská bystrica (slovaquie): anisien, pelsonien (steinalmkalk) 1966 physoporella dissita .bystrický, pl. vi, fig. 4.ponická lehôtka poniky oravce postredná môlëa, e banská bystrica (slovaquie): anisien 1966 oligoporella pilosa var. i n t u s a n n u l a t a .miπík, pl. iii, fig. 1.silická brezová, slovenský kras (slovaquie): anisien, pelsonien 1967a physoporella praealpina .herak, pl. 9, fig. 2.ligaridi, khíos / chios (grèce): anisien 1970 oligoporella pilosa v a r . i n t u s a n n u l a t a .pantiê, pl. viii, fig. 3-4.ædrelo, e serbie (yougoslavie): anisien, pelsonien (“zone avec rhynchonella decurtata”) 1970 oligoporella pilosa i n t u s a n n u l a t a .patrulius, pl. i, fig. 6.valea nadaş, racoşul de sus, perşani mts, braşov (roumanie): anisien, pelsonien 1973 (?) oligoporella pilosa var. intusannulata .popa & dragastan, pl. ix, fig. 34.e lorǎu, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à d a d o c r i n u s communis) 1973 (?) physoporella pauciforata var. g e m e r i c a.popa & dragastan, pl. iv, fig. 16 pars; pl. x, fig. 40; pl. xi, fig. 41.e vǎii iadului, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à dadocrinus communis); pl. v, fig. 19 pars.e vǎii iadului, bulz, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à d a d o c r i n u s communis) 1975 oligoporella pilosa var. i n t u s a n n u l a t a .dragastan & grǎdinaru, pl. iii, fig. 15.s dunavát, tulcea (roumanie): anisien, pelsonien-illyrien inférieur 1975 non oligoporella pilosa var. intusannulata [= physoporella praealpina ].pantiê-prodanoviê, pl. xxvi, fig. 1 pars 114 geologia croatica 53/1 1978 oligoporella pilosa var. i n t u s a n n v e l a t a [s i c].anelkoviê, pl. lxv, fig. 6, extrait de herak (1965: pl. xi, fig. 7) 1980 oligoporella pilosa (forma intusannulata) [sic].dragastan, pl. iii, fig. 3 & 5.valea saratii, perşani mts, braşov (roumanie): anisien moyen 1986 oligoporella pilosa var. i n t u s a n n u l a t a .bystrický, pl. i, fig. 1-2 & 8.silická brezová, slovenský k r a s (slovaquie): anisien, bithynien-illyrien inférieur (physoporella pauciforata oligoporella pilosa assemblage zone) 1988 oligoporella .sartorio & venturini, p. 53 haut, extrait de assereto et al. (1965: pl. 78.a détail) 1989 oligoporella pilosa var. intusannulata .buëek, pl. i, fig. 3.se plavecké podhradie, malé karpaty (slovaquie): anisien, ? pelsonien 1994 oligoporella pilosa v a r . i n t u s a n n u l a t a .bucur et al., pl. 12, fig. 11.sasca zone, caraşs e v e r i n (roumanie): anisien, pelsonien-illyrien inférieur (sasca fm, valea susara limestone member) 1994 non oligoporella pilosa var. intusannulata [= oligoporella pilosa var. pilosa].bucur et al., pl. 12, fig. 15 oligoporella pilosa var . pilosa pia ex bystricky´ 1964 [= forma typica pia 1935, nom. nud. ] 1912 oligoporella pilosa n. sp.pia, pl. iv(iii), fig. 1-4 & 6-7.w lapëiêi, budva, monténégro (yougoslavie): trias moyen; pl. iv(iii), fig. 8.staniπiêi vallée du grkova voda, budva, monténégro (yougoslavie): trias moyen.7 des 8 types: pl. iv(iii), fig. 1, lame mince n° i/11; pl. iv(iii), fig. 2, lame mince n° i/9; pl. iv(iii), fig. 3-4, lame mince n° i/1; pl. iv(iii), fig. 6, lame mince n° i/10; pl. iv(iii), fig. 7, lame mince n° i/6; pl. iv(iii), fig. 8, lame mince n° v/1, collection j. von pia, naturhistorisches museum, wien (autriche) 1912 non oligoporella pilosa n. sp. [= teutloporella tenuis].pia, pl. iv(iii), fig. 5.1 des 8 types: pl. iv(iii), fig. 5, lame mince n° i/3, collection j. von pia, naturhistorisches museum, wien (autriche) 1912 (?) physoporella minutula n. comb.pia, pl. vi(v), fig. 11.mythen, zweckenalp, schwyz (suisse): trias ? moyen (wettersteinkalk) 1925 oligoporella pilosa .pia, pl. i, fig. 8.e ivanoviêi, ene budva, monténégro (yougoslavie): anisien 1 9 3 5 a (nom. nud.) oligoporella pilosa forma typica n. forma.pia, fig. 5 & 9.n haliluêi, e sarajevo (bosnieherzégovine): anisien, pelsonien; fig. 6 & 10.sw studenkoviêi, trebeviê, sarajevo (bosnie-herzégovine): anisien; fig. 7.w trebeviê, s sarajevo (bosnie-herzégovine): anisien, hydaspien supérieur pelsonien; fig. 8 & 11.ograda, areæin brijeg grab, bosansko grahovo (bosnie-herzégovine): anisien, ? hydaspien 1935a (nom. nud.) (?) oligoporella pilosa forma typica n. forma [= ? physoporella praealpina ].pia, fig. 12.sw studenkoviêi, trebeviê, sarajevo (bosnie-herzégovine): anisien 1940b (?) oligoporella pilosa var. ind.pia, pl. 1, fig. 2-5.silická brezová, slovenský kras (slovaquie): anisien, pelsonien 1 9 4 0 b (nom. nud.) oligoporella pilosa t y p i c a.pia, pl. 1, fig. 8.silická brezová, slovenský kras (slovaquie): anisien, pelsonien 1 9 5 7 (nom. nud.) oligoporella pilosa t y p i c a.bystrický, pl. iv, fig. 1-2.silická brezová, slovenský kras (slovaquie): anisien inférieur-moyen 1959 non oligoporella pilosa [= physoporella intusannulata nom. nud.].andrusov, pl. xi, fig. 3, extrait de bystrický (1957: pl. v, fig. 2) 1963 oligoporella .herak, fig. 32, à droite.sv. rok, lika (croatie): anisien 1964 oligoporella pilosa v a r . p i l o s a , nom. nov.bystrický, pl. x, fig. 2 & 6.pleπivec, silická brezová, slovenský kras (slovaquie): anisien, pelsonien-illyrien basal; pl. x, fig. 4, extrait de bystrický (1957: pl. iv, fig. 1); pl. xi, fig. 2.zakázané, silická planina, slovenský kras (slovaquie): anisien, pelsonienillyrien basal; pl. xi, fig. 4.pleπivecká planina, slovenský kras (slovaquie): anisien, pelsonien-illyrien basal 1964 (?) oligoporella pilosa v a r . ind.bystrický, pl. xi, fig. 6.pleπivecká planina, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur 1965 non oligoporella pilosa [= physoporella intusannulata nom. nud.].andrusov, fig. 32, extrait de bystrický (1957: pl. v, fig. 2) 1965 non oligoporella pilosa v a r . p i l o s a [= oligoporella pilosa v a r . i n t u s a n n u l a t a ].assereto et al., pl. 78.a & pars; pl. 81, fig. 2 115granier & grgasoviê: les algues dasycladales du permien et du trias... 1965 oligoporella pilosa var. v a r i c a n s .herak, pl. xi, fig. 4 & 8.wsw klanac pucaloviêa, sv. rok, lika (croatie): anisien; pl. xi, fig. 9, extrait de herak (1963: fig. 32, à droite) 1967a oligoporella pilosa .herak, pl. 7, fig. 3-4.ligaridi, khíos / chios (grèce): anisien 1970 oligoporella pilosa v a r . p i l o s a.pantiê, pl. v, fig. 1-3.ædrelo, e serbie (yougoslavie): anisien, pelsonien (“zone avec rhynchonella decurtata”) 1970 physoporella varicans .pantiê, pl. ix, fig. 1-4.ædrelo, e serbie (yougoslavie): anisien, pelsonien (“zone avec rhynchonella decurtata”) 1970 oligoporella pilosa pilosa .patrulius, pl. ii, fig. 6-7.valea lupşa, perşani mts, braşov (roumanie): anisien, pelsonien-illyrien inférieur 1972 (?) oligoporella pilosa .bleahu et al., pl. iv, fig. 2-7.vaşcǎu plateau, apuseni mts, bihor (roumanie): anisien moyen-supérieur 1973 non oligoporella cf. pilosa.bulle, pl. ii, fig. 10-11.ene oraovec, titov veles (macédoine): anisien 1973 oligoporella pilosa .popa & dragastan, pl. ix, fig. 33 & 35-36.e lorǎu, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à dadocrinus communis) 1975 oligoporella pilosa.dragastan & grǎdinaru, pl. iii, fig. 16-18 & 20 pars; pl. vi pars.s dunavát, tulcea (roumanie): anisien, pelsonien-illyrien inférieur 1977 (?) dasycladaceae.gaździcki & smit, pl. 1, fig. 3 pars.mogota bukit kalong, s kodiang, kedah, nw malaysia (malaisie): anisien-ladinien (kodiang limestone fm) 1977 (?) o l i g o p o r e l l a sp.gaździcki & smit, pl. 2, fig. 6.mogota bukit kalong, s kodiang, kedah, nw malaysia (malaisie): anisien-ladinien (kodiang limestone fm) 1978 oligoporella pilosa var. varicans .anelkoviê, pl. lxv, fig. 4, extrait de herak (1965: pl. xi, fig. 4) 1978 oligoporella pilosa .e. flügel, pl. 22, fig. 4.silická brezová, slovenský kras (slovaquie): anisien, pelsonien 1980 oligoporella pilosa .dragastan, pl. iv, fig. 1, extrait de popa & dragastan (1973: pl. ix, fig. 33) 1982 oligoporella pilosa .e. flügel, pl. 29, fig. 6, extrait de e. flügel (1978: pl. 22, fig. 4) 1986 oligoporella pilosa v a r . p i l o s a.bystrický, pl. i, fig. 9.silická brezová, slovenský kras (slovaquie): anisien, bithynien-illyrien inférieur (physoporella pauciforata oligoporella pilosa assemblage zone) 1987 (?) dasycladacea.oravecz-scheffer, pl. xxv, fig. 2.forage szentantalfa 1 (szaf. 1), veszprém, balaton (hongrie): anisien, illyrien (tagyon limestone formation) 1987 oligoporella pilosa .strutinski et al., pl. ii, fig. 3-4.sasca montana, caraş-severin (roumanie): anisien, pelsonien-illyrien inférieur 1989 oligoporella pilosa var. pilosa.buëek, pl. i, fig. 4.se plavecké podhradie, malé karpaty (slovaquie): anisien, ? pelsonien 1991 oligoporella pilosa var. pilosa.bucur, pl. 42, fig. 2, 6, 13 & 15.dealul redut sasca montana, resita, c a r aş-severin (roumanie): anisien moyen; pl. 42, fig. 12, 14 & 16.valea remetea stinapari, resita, caraş-severin (roumanie): anisien moyen 1993 physoporella pauciforata undulata .budai, lelkes & piros, pl. v, fig. 4.forage drt. 1, dörgicse, veszprém, balaton (hongrie): anisien (tagyon limestone fm) 1993 oligoporella pilosa .budai, lelkes & piros, pl. vi, fig. 2.forage szentantalfa 1 (szaf. 1), veszprém, balaton (hongrie): anisien (tagyon limestone fm) 1993 p h y s o p o r e l l a .budai, lelkes & piros, pl. vi, fig. 4 pars.forage drt. 1, dörgicse, veszprém, balaton (hongrie): anisien (tagyon limestone fm) 1994 oligoporella pilosa var. pilosa.bucur et al., pl. 10, fig. 1 pars & 5 pars; pl. 11, fig. 17 & 19 pars; pl. 12, fig. 2, 4-6, 9-10, 12 & 14; pl. 13, fig. 1 pars.sasca zone, caraş-severin (roumanie): anisien, pelsonienillyrien inférieur (sasca fm, valea susara limestone member); pl. 11, fig. 16, extrait de bucur (1991: pl. 42, fig. 13); pl. 11, fig. 18, extrait de bucur (1991: pl. 42, fig. 15); pl. 12, fig. 1, extrait de bucur (1991: pl. 42, fig. 2); pl. 12, fig. 3, extrait de bucur (1991: pl. 42, fig. 16); pl. 12, fig. 7, extrait de bucur (1991: pl. 42, fig. 6); pl. 12, fig. 8, extrait de bucur (1991: pl. 42, fig. 16) 1994 oligoporella pilosa v a r . i n t u s a n n u l a t a .bucur et al., pl. 12, fig. 15.sasca zone, caraşs e v e r i n (roumanie): anisien, pelsonien-illyrien inférieur (sasca fm, valea susara limestone member) 1994 oligoporella pilosa var. pilosa.e. flügel et al., pl. 2, fig. 3.bled (slovénie): anisien, ? ‘aegean’ pelsonien 1994 (?) oligoporella cf. pilosa.e. flügel et al., pl. 2, fig. 2.bled (slovénie): anisien, ? ‘aegean’ pelsonien 116 geologia croatica 53/1 1997 oligoporella pilosa v a r . p i l o s a.bucur, pl. i, fig. 8 & 12.sasca zone, caraş-severin (roumanie): anisien, pelsonien-illyrien inférieur (sasca fm, valea susara limestone member); pl. i, fig. 1 & 16, extrait de pia (1912: pl. iv(iii), fig. 3); pl. i, fig. 2, extrait de bucur (1991: pl. 42, fig. 13); pl. i, fig. 3, extrait de bucur et al. (1994: pl. 11, fig. 17); pl. i, fig. 4, extrait de bucur et al. (1994: pl. 12, fig. 4); pl. i, fig. 5, extrait de bucur et al. (1994: pl. 10, fig. 1 pars); pl. i, fig. 6, extrait de bucur et al. (1994: pl. 12, fig. 2); pl. i, fig. 7, extrait de bucur (1991: pl. 42, fig. 16); pl. i, fig. 9, extrait de bucur et al. (1994: pl. 12, fig. 6); pl. i, fig. 10, extrait de bucur et al. (1994: pl. 13, fig. 1 pars); pl. i, fig. 11, extrait de bucur et al. (1994: pl. 11, fig. 19 pars); pl. i, fig. 13, extrait de bucur et al. (1994: pl. 12, fig. 12); pl. i, fig. 14, extrait de bucur (1991: pl. 42, fig. 6); pl. i, fig. 15, extrait de bucur (1991: pl. 42, fig. 16).lectotype désigné par i.i. bucur & t. grgasoviê: pl. i, fig. 1 & 16 = pl. iv(iii), fig. 3 in pia (1912) , lame mince n° i/1, collection j. von pia, naturhistorisches museum, wien (autriche) oligoporella pilosa var . physoporelloidea pia 1940 1940b oligoporella pilosa forma physoporelloidea n. forma.pia, pl. 1, fig. 11.silická brezová, slovenský kras (slovaquie): anisien, pelsonien.type: pl. 1, fig. 11, collection j. von pia, naturhistorisches museum, wien (autriche) 1986 oligoporella pilosa var. physoporelloidea.bystrický, pl. i, fig. 7.silická brezová, slovenský kras (slovaquie): anisien oligoporella pilosa var . subvaricans pia 1935 1935a oligoporella pilosa var. subvaricans n. var.pia, fig. 20.ograda, areæin brijeg grab, bosansko grahovo (bosnie-herzégovine): anisien, ? hydaspien.type: fig. 20, lame mince n° 231/10, collection j. von pia, naturhistorisches museum, wien (autriche) 1965 oligoporella pilosa var. s e m i v a r i c a n s [s i c].herak, pl. xi, fig. 6.wsw klanac pucaloviêa, sv. rok, lika (croatie): anisien 1978 oligoporella pilosa var. semivaricans [sic].anelkoviê, pl. lxv, fig. 5, extrait de herak (1965: pl. xi, fig. 6) oligoporella pilosa var . varicans pia 1935 1935a oligoporella pilosa var. varicans n. var.pia, fig. 21, 23-24 & 26.n haliluêi, e sarajevo (bosnieherzégovine): anisien, pelsonien; fig. 22 & 25.ograda, areæin brijeg grab, bosansko grahovo (bosnie-herzégovine): anisien, ? hydaspien; fig. 27.nw ograda, areæin brijeg grab, bosansko grahovo (bosnie-herzégovine): anisien.types: fig. 21, lame mince n° 577/a; fig. 22 & 25, lame mince n° 235/b; fig. 23, lame mince n° 575/b; fig. 24, lame mince n° 574; fig. 26-27, lame mince n° ?, collection j. von pia, naturhistorisches museum, wien (autriche) 1940b oligoporella pilosa forma varicans [sic].pia, pl. 1, fig. 9.silická brezová, slovenský kras (slovaquie): anisien, pelsonien 1957 oligoporella pilosa v a r i c a n s .bystrický, pl. iv, fig. 7; pl. v, fig. 3.silická brezová, slovenský k r a s (slovaquie): anisien, pelsonien; pl. v, fig. 1 & 4-5.pleπivecká planina, slovenský kras (slovaquie): anisien, pelsonien 1957 non oligoporella pilosa varicans [= physoporella intusannulata nom. nud.].bystrický, pl. v, fig. 2 1964 oligoporella pilosa var. v a r i c a n s .bystrický, pl. xii, fig. 4.pleπivecká planina, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur; pl. xii, fig. 5.silická brezová, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur 1964 (?) ? oligoporella pilosa var. varicans .bystrický, pl. xii, fig. 7.slovenský kras (slovaquie): ? 1964 non oligoporella pilosa var. v a r i c a n s [= physoporella intusannulata nom. nud.].bystrický, pl. xii, fig. 6, extrait de bystrický (1957: pl. v, fig. 2) 1965 non oligoporella pilosa var. varicans [= oligoporella pilosa var. intusannulata ].assereto et al., pl. 79, fig. 1; pl. 81, fig. 6-7 1965 (?) oligoporella pilosa var. v a r i c a n s .assereto et al., pl. 79, fig. 5.w castelfranco, val gola / val camónica, ne bergamo, lombardia (italie): anisien (calcare di camorelli) 1965 non oligoporella pilosa var. v a r i c a n s [= oligoporella pilosa v a r . p i l o s a].herak, pl. xi, fig. 4 & 8; pl. xi, fig. 9, extrait de herak (1963: fig. 32, à droite) 1966 non oligoporella pilosa var. varicans [= physoporella intusannulata nom. nud.].miπík, pl. ii, fig. 2, extrait de bystrický (1957: pl. v, fig. 2) 117granier & grgasoviê: les algues dasycladales du permien et du trias... 1978 non oligoporella pilosa var. v a r i c a n s [= oligoporella pilosa v a r . p i l o s a].anelkoviê, pl. lxv, fig. 4, extrait de herak (1965: pl. xi, fig. 4) 1986 oligoporella pilosa var. varicans .bystrický, pl. i, fig. 3.silická brezová, slovenský kras (slovaquie): anisien, bithynien-illyrien inférieur (physoporella pauciforata oligoporella pilosa assemblage zone) 1993 oligoporella pilosa v a r i c a n s .senowbari-daryan et al., pl. 52, fig. 7.2.valdáora / olang, pusteria / pustertal, trentino alto adige (italie): anisien; pl. 56, fig. 1-5, 6.1 & 7-9.valdáora / olang, pusteria / pustertal, trentino alto adige (italie): anisien supérieur 1994 oligoporella pilosa v a r . v a r i c a n s .e. flügel et al., pl. 2, fig. 1.bled (slovénie): anisien, ? ‘aegean’ pelsonien oligoporella prisca pia 1912 1912 oligoporella prisca n. sp.pia, pl. v(iv), fig. 1-2.sw kleinzel, niederösterreich (autriche): trias moyen (reiflinger kalk); pl. v(iv), fig. 3-7.sandkogel / schlegelberg, vorderstaff, schwarzenbach an der pielach, niederösterreich (autriche): trias moyen (reiflinger kalk); pl. v(iv), fig. 8.schwarzenberg, w türnitz, niederösterreich (autriche): trias moyen (reiflinger kalk).types: pl. v(iv), fig. 1-2, lame mince n° lxxix/1; pl. v(iv), fig. 3 & 5-7, lame mince n° xxxiv/2; pl. v(iv), fig. 4, lame mince n° xxxiv/1; pl. v(iv), fig. 8, lame mince n° lvi/1, collection j. von pia, naturhistorisches museum, wien (autriche) 1912 physoporella pauciforata emend.pia, pl. v(iv), fig. 18.sandkogel / schlegelberg, vorderstaff, schwarzenbach an der pielach, niederösterreich (autriche): trias moyen (reiflinger kalk) 1964 (?) o l i g o p o r e l l a cf. p r i s c a ?.bystrický, pl. ix, fig. 4 ? & 5.silická brezová, slovenský kras (slovaquie): anisien, pelsonien; pl. ix, fig. 6.silická brezová, slovenský kras (slovaquie): anisien, pelsonien, ou d’après bystrický (1986): anisien, pelsonien terminal-illyrien inférieur (physoporella pauciforata oli goporella pilosa assemblage zone) 1973 non o l i g o p o r e l l a cf. p r i s c a [= physoporella pauciforata var. p a u c i f o r a t a ].popa & dragastan, pl. viii, fig. 31 1986 (?) oligoporella aff. prisca .bystrický, pl. i, fig. 4, extrait de bystrický (1964: pl. ix, fig. 6) oligoporella propilosa endo 1969 1969 oligoporella propilosa n. sp.endo, pl. xxxiii, fig. 4-8.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à neoschwagerina simplex / partie inférieure).holotype: pl. xxxiii, fig. 4, lame mince n° gk.d 13732, kyūshū university, fukuoka (japon) oligoporella serripora pia 1912 1912 oligoporella serripora n. sp.pia, pl. iv(iii), fig. 9-11.mte serla / sarlkofel, se villabassa / niederdorf, pusteria / pustertal, trentino alto adige (italie): trias moyen.types: pl. iv(iii), fig. 9, lame mince n° liv/2; pl. iv(iii), fig. 10, lame mince n° liv/3; pl. iv(iii), fig. 11, lame mince n° liv/8, collection j. von pia, naturhistorisches museum, wien (autriche) oligoporella skawadai endo 1952 1952c oligoporella s-kawadai n. sp.endo, pl. 23, fig. 9-10.mt kurohime, nishikubiki-gun, niigata-ken, honshū (japon): permien “moyen” .“holotype” (syntypes): pl. 23, fig. 9-10, lames minces n° 117 & 124, department of earth sciences, saitama university, urawa (japon) 1956 oligoporella s-kawadai .endo, pl. 24, fig. 5.hinoda, chichibu-shi, saitama-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne); pl. 24, fig. 6.sakaishi, agano-mura, hannōshi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne); pl. 24, fig. 7-8.shimokuzū, agano-mura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne); pl. 24, fig. 9.shōwadenkō factory, kagemori-mura, chichibu-gun, saitama-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne) 1961a oligoporella s-kawadai.endo, pl. 2, fig. 4, extrait de endo (1956: pl. 24, fig. 5) 1961b (?) oligoporella cf. s k a w a d a i.endo, pl. 12, fig. 5; pl. 18, fig. 1.n manganji, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 13, fig. 7.sukawa, santō-machi, saka118 geologia croatica 53/1 ta-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 17, fig. 1.w nagaoka, santōmachi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm) 1963 oligoporella s’kawadai [sic].johnson, pl. 66, fig. 5, extrait de endo (1956: pl. 24, fig. 5); pl. 66, fig. 6, extrait de endo (1956: pl. 24, fig. 7); pl. 66, fig. 7, extrait de endo (1956: pl. 24, fig. 6) 1995 oligoporella skawadai orth. mut.granier & deloffre, p. 70, non figurée oligoporella sola endo 1969, non 1968 [cf. uragiellopsis sola (endo 1969) vachard 1980 ] paraepimastopora roux 1979 *paraepimastopora kansasensis (johnson 1951) roux 1979 [= epimastopora kansasensis johnson 1951, non 1946 ] 1 9 4 6 b (nom. nud.) epimastopora kansasensis n. sp.johnson, pl. 1, fig. 5-6.elk county, se kansas (états-unis d’amérique): carbonifère, pennsylvanien supérieur (base lecompton limestone fm, spring branch m e m b e r ).“type” (syntypes): pl. 1, fig. 5-6, lame mince n° 698, echantillon ja2575, collection j.h. johnson, colorado school of mines, golden (états-unis d’amérique) 1961 epimastopora kansasensis .johnson, pl. 48, fig. 2-3.elk county, se kansas (états-unis d’amérique): carbonifère, pennsylvanien (lecompton limestone) 1963 epimastopora kansasensis .johnson, pl. 14, fig. 5, extrait de johnson (1946: pl. 1, fig. 5); pl. 56, fig. 23, extrait de johnson (1961: pl. 48, fig. 2-3) 1969 (?) epimastopora sp. cf. e. kansasensis.toomey, pl. 152, fig. 6 & 8-10.woodson county, kansas (étatsunis d’amérique): carbonifère, pennsylvanien, ‘virgilian’ (leavenworth limestone); pl. 152, fig. 7.osage county, n oklahoma (états-unis d’amérique): carbonifère, pennsylvanien, ‘virgilian’ (leavenworth limestone) 1972 (?) epimastopora kansaensis [s i c].homann, pl. 4, fig. 28.n trogkofelkar, zottach-kogel trogkofel / creta di aip, kärnten (autriche): sakmarien (rattendorfer schichten, oberer pseudoschwagerinenkalk) 1977 epimastopora .toomey et al., fig. 13.c.sacramento mts, new mexico (états-unis d’amérique): carbonifère, pennsylvanien supérieur 1979a paraepimastopora kansasensis .roux, pl. 17, fig. 1.otto fiord, ellesmere, nunavut (canada): carbonifère, silésien, moscovien moyen ou plus jeune (fm nansen); pl. 17, fig. 2-4.fish creek, yukon territory (canada): sakmarien 1979b paraepimastopora kansasensis n. gen. n. comb.roux, p. 803 & 809, non figurée.typification de l’espèce; “holotype” (lectotype): pl. 1, fig. 5 in johnson (1946), lame mince n° 698, echantillon ja2575, collection j.h. johnson, colorado school of mines, golden (états-unis d’amérique) 1980 epimastopora kansasensis .e. flügel & flügel-kahler, pl. 6, fig. 6 pars.ne col mezzodì, forni avoltri, friuli venezia giulia (italie): permien inférieur (trogkofelkalk) 1980 “e p i m a s t o p o r a” k a n s a s e n s i s.vachard, pl. 23, fig. 1 pars & 2.khwahan, tezak (afghanistan): artinskien supérieur 1982 paraepimastopora kansasensis .mamet & roux, pl. 1, fig. 4.little fish (cache) creek, yukon territory (canada): sakmarien 1987 paraepimastopora kansasensis .mamet et al., pl. 17, fig. 1-4, extrait de roux (1979a: pl. 17, fig. 1-4) 1989 paraepimastopora kansasensis .roux, pl. i, fig. 1-6; pl. ii, fig. 1-8; pl. iii, fig. 1-2 & 5.elk county, se kansas (états-unis d’amérique): carbonifère, pennsylvanien, ‘virgilian’ inférieur (spring branch limestone member) 1990 epimastopora kansasensis .e. flügel, pl. 4, fig. 5.balya-edremit, sw balya, w balikesir (turquie): murghabien supérieur (zone à neoschwagerina / partie supérieure) paraepimastopora kanumai (endo in endo et kanuma 1954) roux 1979 [= epimastopora kanumai endo in endo et kanuma 1954 ] 1954 epimastopora kanumai n. sp.endo in endo & kanuma, pl. xiii, fig. 8-10.akiyama, okumyōg a t a mura, gujō-gun, gifu-ken, honshū (japon): carbonifère, silésien (oppara fm, zone à t r i t i c i t e s).syntypes: pl. xiii, fig. 1-3, lames minces n° 179-181, department of earth sciences, saitama universi ty, urawa (japon) 119granier & grgasoviê: les algues dasycladales du permien et du trias... 1954 epimastopora kanumai .endo, pl. xviii, fig. 6-9.kinshō-zan hill, mino-akasaka, n o _ gaki-shi, gifuken, honshū (japon): permien “moyen”-”supérieur” / partie inférieure 1957 epimastopora kanumai .endo, pl. 37, fig. 9-10; pl. 38, fig. 1.misaka, shinsaka-mura, jinseki-gun, hiroshima-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie inférieure) 1957 epimastopora kanumai .endo & horiguchi, pl. xiii, fig. 5; pl. xiv, fig. 1-2.kamitakara-mura, fukuji, gifu-ken, honshū (japon): permien inférieur (ichinotani group, zone à triticites) 1959 epimastopora kanumai .endo, pl. 30, fig. 5.sotedani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien inférieur-moyen (gonbō fm, zone à parafusulina ) 1961a epimastopora kanumai .endo, pl. 8, fig. 6, extrait de endo & horiguchi (1957: pl. xiv, fig. 2) 1961b epimastopora kanumai .endo, pl. 5, fig. 4.sukawa, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 6, fig. 3; pl. 7, fig. 1.w nagaoka, santō-machi, sakatagun, shiga-ken, honshū (japon): permien inférieur (samegai fm) 1961c epimastopora kanumai .endo, pl. 1, fig. 1.kuroiwa-chōjagamori, se kuroiwa, kyowa, shuhōc hō, ne mine-shi, yamaguchi-ken, honshū (japon): permien inférieur (akiyoshi limestone group, zone à pseudoschwagerina , sous-zone à triticites simplex); pl. 1, fig. 2.shigeyasu o _ mine, n mine-shi, yamaguchi-ken, honshū (japon): permien inférieur (akiyoshi limestone group, zone à pseudoschwagerina , sous-zone à triticites simplex sous-zone à pseudofusulina vulgaris ); pl. 1, fig. 3; pl. 2, fig. 2.e kyozuka, mine-gun, yamaguchi-ken, honshū (japon): permien inférieur (akiyoshi limestone group, zone à pseudoschwagerina ) 1963 epimastopora kanumai .johnson, pl. 57, fig. 3, extrait de endo (1957: pl. 38, fig. 1); pl. 57, fig. 4-5, extrait de endo (1954: pl. xviii, fig. 6-7); pl. 57, fig. 6-7, extrait de endo (1957: pl. 37, fig. 9-10); pl. 57, fig. 8-9, extrait de endo (1954: pl. xviii, fig. 8-9) 1969 epimastopora kanumai .endo, pl. xli, fig. 2-3.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina ) 1972 epimastopora kanumai .homann, pl. 4, fig. 26.nw zottach-kogel, kärnten (autriche): sakmarien (rattendorfer schichten, oberer pseudoschwagerinenkalk) 1979b paraepimastopora kanumai n. comb.roux, p. 810, non figurée 1980 (?) epimastopora c f . k a n u m a i.e. flügel & flügel-kahler, pl. 6, fig. 7.ne col mezzodì, forni avoltri, friuli venezia giulia (italie): permien inférieur (trogkofelkalk) 1981 “e p i m a s t o p o r a ” k a n u m a i.vachard in vachard & montenat, pl. 3, fig. 3.khwaja bahadur, tezak (afghanistan): murghabien moyen 1982 epimastopora kanumai .mu, pl. v, fig. 6.xizang / tibet (chine populaire): permien “inférieur” / partie supérieure 1984 epimastopora kanumai .nakamura & chisaka, pl. 7, fig. 1-2.mt atagoyama, chôshi-shi, chiba-ken, honshū (japon): permien “supérieur” (takagami conglomerate) 1996 epimastopora kanumai .pantiê-prodanoviê, pl. i, fig. 5-6.gaj, vlaπiê mt, oseëina, w krupanj, serbie (yougoslavie): permien supérieur paraepimastopora lateinterporosa (endo 1961) roux 1979 [= epimastopora lateinterporosa endo 1961 ] 1961c epimastopora lateinterporosa n. sp.endo, pl. 1, fig. 4.e kyozuka, mine-gun, yamaguchi-ken, h o n s hū (japon): permien inférieur (akiyoshi limestone group, zone à p s e u d o s c h w a g e r i n a ); pl. 2, fig. 1.ne okugawara, isa, s mine-shi, yamaguchi-ken, honshū (japon): permien inférieur (akiyoshi limestone group, zone à p s e u d o s c h w a g e r i n a ).holotype: pl. 1, fig. 4, lame mince n° 1089, dept. of geology, kyūshū univ. (japon) 1969 epimastopora ? lateinterporosa .endo, pl. xlii, fig. 4.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina ) 1979b paraepimastopora lateinterporosa n. comb.roux, p. 810, non figurée paraepimastopora longituba (endo 1957) roux 1979 [= epimastopora longituba endo 1957] 1957 epimastopora longituba n. sp.endo, pl. 38, fig. 2.arito, taishaku-mura, hiba-gun, hiroshima-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne); pl. 38, fig. 3.zenbutsujidani, taishaku-mura, hiba-gun, hiroshima-ken, honshū (japon): permien “inférieur” (yukisawa subsys120 geologia croatica 53/1 tem / partie supérieure).syntypes: pl. 38, fig. 2, lame mince n° ? 569 ou ? 509; pl. 38, fig. 3, lame mince n° 556, department of earth sciences, saitama university, urawa (japon) 1979b paraepimastopora longituba n. comb.roux, p. 810, non figurée paraepimastopora regularis (johnson 1951) roux 1979 [= epimastopora regularis johnson 1951, non 1946 ] 1 9 4 6 b (nom. nud.) epimastopora regularis n. sp.johnson, pl. 2, fig. 1-2.riley county, manhattan, kansas (états-unis d’amérique): permien “inférieur” (fm foraker, membres hughes creek shale et americus l i m e s t o n e ).“type”: pl. 2, fig. 1-2, lame mince n° 630, échantillon n° ja233a, collection j.h. johnson, colorado school of mines, golden (états-unis d’amérique) 1961 epimastopora regularis .johnson, pl. 48, fig. 4, extrait de johnson (1946: pl. 2, fig. 1) 1963 epimastopora regularis .johnson, pl. 56, fig. 4, extrait de johnson (1946: pl. 2, fig. 1); pl. 57, fig. 1-2, extrait de johnson (1946: pl. 2, fig. 1-2) 1979b paraepimastopora regularis n. comb.roux, p. 810, non figurée 1996 epimastopora regularis .pantiê-prodanoviê, pl. i, fig. 4.gaj, vlaπiê mt, oseëina, w krupanj, serbie (yougoslavie): permien supérieur pentaporella senowbari-daryan 1978 *pentaporella rhaetica senowbari-daryan 1978 1978 pentaporella rhaetica n. gen. n. sp.senowbari-daryan, fig. 1-9.gruber, feichtenstein, hintersee, salzburg (autriche): rhétien supérieur.holotype: fig. 2, lame mince n° z/48a, collection b. senow bari-daryan, botan.-paläobotanische abteilung, senckenberg-museum, frankfurt am main (alle magne) 1979 pentaporella rhaetica .senowbari-daryan & schäfer, pl. 1, fig. 11.gruber, feichtenstein, hintersee, salzburg (autriche): trias supérieur 1980 (?) c l y p e i n a sp.senowbari-daryan, pl. 14, fig. 5.gruber, feichtenstein, hintersee, salzburg (autriche): rhétien supérieur 1980 pentaporella rhaetica .senowbari-daryan, pl. 12, fig. 8; pl. 14, fig. 9.gruber, feichtenstein, hintersee, salzburg (autriche): rhétien supérieur 1981 pentaporella rhaetica .e. flügel, fig. 10.d.gruber, feichtenstein, hintersee, salzburg (autriche): trias supérieur 1993 pentaporella rhaetica .senowbari-daryan & e. flügel, pl. 9, fig. 1-3.gruber, feichtenstein, hintersee, salzburg (autriche): rhétien supérieur permoperplexella elliott 1968 *permoperplexella attenuata elliott 1968 1968a permoperplexella attenuata n. gen. n. sp.elliott, pl. 17, fig. 1-5.ora, mosul liwa, n irak (irak): permien (zinnar fm).holotype: pl. 17, fig. 4, lame mince n° v.52085; paratypes: pl. 17, fig. 1, lame mince n° v.52084; pl. 17, fig. 2-3 & 5, lame mince n° v.52085, british museum (natural history), london (royaume-uni) 1988 permoperplexella .deloffre, pl. 2, fig. 22, extrait de elliott (1968a: pl. 17, fig. 1) permoperplexella wargaliae dragastan et al. 1990 1990 permoperplexella wargaliae n. sp.dragastan et al., pl. i, fig. 4-5.sakesar, salt range (pakistan): murghabien supérieur djulfien supérieur (wargal fm).holotype: pl. i, fig. 4, lame mince n° 0561, échantillon 44; paratype: pl. i, fig. 5, lame mince n° 0562, échantillon 44, collection l.p.b.v., bucarest (roumanie) 121granier & grgasoviê: les algues dasycladales du permien et du trias... permopora elias 1947 *permopora keenae elias 1947 1947 permopora keenae n. gen. n. sp.elias, pl. 18, fig. 1-11.childress county, texas (états-unis d’amérique): permien “supérieur” (childress dolomite).holotype: pl. 18, fig. 1 pars & 11, spécimen n° 2, échantillon n° 7904, collection beede, stanford university (états-unis d’amérique) 1961a permipora keenae [sic].endo, pl. 5, fig. 6, extrait de elias (1947: pl. 18, fig. 11) 1963 permoporella keenae [sic].johnson, pl. 67, fig. 1-11, extrait de elias (1947: pl. 18, fig. 1-11) petrascula gümbel 1873, emend. bernier 1979 petrascula ? stratenica bystrický 1979 1979 petrascula ? stratenica n. sp.bystrický, pl. vii, fig. 1-5; pl. viii, fig. 1-8.ne colline kopa, n stratená, n dobπiná, stratenská hornatina mts (slovaquie): norien (furmaneckalk), ou d’après bystrický (1986): norien, alaunien (h e t e r o p o r e l l a taxon-range superzone).holotype: pl. vii, fig. 1, lame mince n° 5966, collection j. bystricky ´, geological institute of the slovak academy of science, bratislava (slovaquie) 1979 (?) ? petrascula a f f . i l l y r i c a.bystrický, pl. iv, fig. 7.muráňska planina, stratenská hornatina mts (slovaquie): norien (furmaneckalk), ou d’après bystrický (1986): norien, sevatien (h e t e r o p o r e l l a t a x o n range superzone) physoporella steinmann 1903, emend. pia 1912 physoporella chichibuensis ishijima et al. 1971 1971 physoporella chichibuensis n. sp.ishijima et al., pl. 14, fig. 1-5.sakaishimachibun, agano-mura, h a n nō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur”.holotype: pl. 14, fig. 1, spécimen n° nsmp1-18094a, national science museum, tokyo (japon) physoporella classiforata endo 1969, nom. nud. 1969 (nom. nud.) physoporella classiforata n. sp.endo, pl. xxiii, fig. 9; xxiv, fig. 1-7.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina zone à neoschwagerina simplex / partie inférieure).holotype: pl. xxiv, fig. 2, lame mince n° gk.d 13321 (d’après le texte) ou pl. xxiv, fig. 7, lame mince n° gk.d 13048 (d’après les légendes des figures), kyūshū university, fukuoka (japon) physoporella croatica herak in granier et deloffre 1995, non 1958 1958 (nom. nud.) physoporella croatica n. sp.herak, fig. 2, n° 1, 2 [= pl. 14, fig. 4, à droite], 3-5, 6 [= pl. 14, fig. 3, en bas, à gauche], 7 [= pl. 14, fig. 1], 8, 9 [= pl. 14, fig. 3, à droite], 10 [= pl. 14, fig. 2, à gauche], 11 [= pl. 14, fig. 2, à droite] & 12 [= pl. 14, fig. 5]; pl. 14, fig. 1-5.miljeviêi, nw knin (croatie): anisien.syntypes: pl. 14, fig. 1-5, lame mince coll. alg. n° 61, 66, 70 & 73-74, collection m. herak, geoloπko-paleontoloπki zavod, prirodoslovno-matematiëki fakultet [geological and palaeontological institute, faculty of sciences ], zagreb (croatie) 1969 (?) physoporella-oligoporella .hurka, fig. 4.d-e, g, h & j.mte serla / sarlkofel, se villabassa / niederdorf, pusteria / pustertal, trentino alto adige (italie): anisien (oberer sarldolomit) 1983 (nom. nud.) physoporella croatica .bystrický, pl. i, fig. 1-4; pl. ii, fig. 11; pl. iii, fig. 12-16; pl. v, fig. 2425.slovenský kras (slovaquie): anisien (steinalmkalk), pelsonien-illyrien inférieur, ou d’après bystrický (1986): anisien, pelsonien (physoporella pauciforata oligoporella pilosa assemblage zone) 1 9 8 3 (nom. nud.) physoporella aff. c r o a t i c a .bystrický, pl. ii, fig. 5-10; pl. iii, fig. 18; pl. v, fig. 26-27.slovenský kras (slovaquie): anisien (steinalmkalk) 1995 physoporella croatica .herak in granier & deloffre, p. 57, non figurée.typification et validation de l’espèce; lectotype: “the right specimen” in pl. 14, fig. 2 in herak (1958), lame mince n° 66, collec 122 geologia croatica 53/1 tion m. herak, geoloπko-paleontoloπki zavod, prirodoslovno-matematiëki fakultet [geological and palaeontological institute, faculty of sciences ], zagreb (croatie) physoporella dissita (gümbel 1872) pia 1912 [= gyroporella dissita gümbel 1872 ] 1872 gyroporella dissita n. sp.gümbel, pl. d.iii, fig. 1.schwarzau im gebirge, niederösterreich (autriche): trias ? moyen (wettersteinkalk, zugspitzegruppe).-type: pl. d.iii, fig. 1, collection gümbel, geologischen reichsanstalt in wien, wien (autriche) 1912 physoporella dissita n. comb.pia, pl. vi(v), fig. 1-4.d’après pia (1920): öfenbach, bachwinkel, n saalfelden, salzburg (autriche): trias ? moyen (wettersteinkalk) 1957 p h y s o p o r e l l a d i s s i t a.bystrický, pl. vi, fig. 6.silická planina, slovenský kras (slovaquie): anisien, pelsonien; pl. vi, fig. 7.soroπka, silická planina, slovenský kras (slovaquie): anisien, pelsonien 1964 p h y s o p o r e l l a d i s s i t a.bystrický, pl. xx, fig. 6; pl. xxi, fig. 7.pipiπ, planina koniart, slovenský k r a s (slovaquie): anisien, pelsonien-illyrien inférieur; pl. xxi, fig. 1, 3-5 & 8.©títnik, n pleπivec, s l o v e n s ký kras (slovaquie): anisien, pelsonien-illyrien inférieur; pl. xxi, fig. 2.gemerská hôrka, w pleπivec, planina koniart, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur; pl. xxi, fig. 6, extrait de bystrický (1957: pl vi, fig. 7) 1964 non physoporella dissita [= ? physoporella praealpina ].bystrický, pl. xxi, fig. 9 1965 (?) physoporella cf. dissita.bystrický & veizer, pl. iv, fig. 3.»ervené vrchy, vysoke tatry (slovaquie): anisien 1966 physoporella dissita.bystrický, pl. vi, fig. 5.ponická lehôtka poniky oravce postredná môlëa, e banská bystrica (slovaquie): anisien, pelsonien (gutensteiner kalk); pl. vii, fig. 1.ponická lehôtka fig. 18 physoporella croatica (herak, 1958, pl. 14, fig. 4 pars), x16. fig. 19 physoporella croatica (herak, 1958, pl. 14, fig. 5), x15. 123granier & grgasoviê: les algues dasycladales du permien et du trias... poniky oravce postredná môlëa, e banská bystrica (slovaquie): anisien, pelsonien (gutensteiner kalk), ou d’après bystrický (1986): anisien, bthynien-illyrien inférieur (physoporella pauciforata oli goporella pilosa assemblage zone); pl. vii, fig. 2.b.ponická lehôtka poniky oravce postredná môlëa, e banská bystrica (slovaquie): anisien 1966 non physoporella dissita [= oligoporella pilosa var. intusannulata ].bystrický, pl. vi, fig. 4 1966 p h y s o p o r e l l a d i s s i t a.peræel (bystrický), pl. xviii, fig. 1-3.biele pohorie, malé karpaty (slovaquie): anisien, hydapsien-pelsonien (gutensteiner kalk) 1967a p h y s o p o r e l l a d i s s i t a .bystrický, pl. i, fig. 5.turík, choëské vrchy (slovaquie): anisien supérieur (choë-dolomit); pl. ii, fig. 2-3.hore-hroni, horná lehota, n brezno, nízke tatry (slovaquie): anisien supérieur (rieflingkalk); pl. ii, fig. 4.vel’ký choë, turík, choëské vrchy (slovaquie): anisien supérieur (choë-dolomit) 1967b physoporella dissita.herak, pl. 2, fig. 2-4; pl. 3, fig. 2-3.n hofkogel, gosaukamm, dachsteingruppe, oberösterreich (autriche): anisien (massenkalk) 1970 physoporella pauciferrata [s i c].papp & turnovsky (herak), pl. 11.sw gosaukamm, dachsteingruppe, salzburg (autriche): anisien (massenkalk) 1972 non physoporella dissita [= physoporella minutula].bleahu et al., pl. iv, fig. 1 1973 (?) p h y s o p o r e l l a d i s s i t a .kotański & »atalov, pl. viii, fig. 1-23.staneto, s troyan, loveë (bulgarie): anisien, pelsonien 1975 physoporella dissita .baltres, pl. i, fig. 1-2.lacul roşu, e carpathes (roumanie): anisien supérieur 1979 physoporella dissita .kotański, pl. 79, fig. 2.c & 5-6.tatry (pologne): anisien, illyrien 1982 physoporella dissita .bystrický, pl. 3, fig. 1 pars.slatinka nad bebravou ©ípkov, stráæovské vrchy, e trencín (slovaquie): anisien (steinalmkalk) 1983 physoporella dissita .bystrický, pl. iii, fig. 19.slovenský kras (slovaquie): anisien (steinalmkalk) 1986 physoporella dissita .bystrický, pl. iii, fig. 1, extrait de bystrický (1966: pl. vii, fig. 1); pl. iii, fig. 2.planina koniart, slovenský kras (slovaquie): anisien, bithynien-illyrien inférieur (physoporella paucifo rata oligoporella pilosa assemblage zone) 1986 physoporella dissita .kotański, pl. ciii, fig. 2.c & 5-6, extrait de kotański (1979: pl. 79, fig. 2.c & 5-6); pl. cv, fig. 17-19.forage winowno 25 ww, winowno, siewierz kozieglowy, haute silésie (pologne): anisien, pelsonien 1989 physoporella dissita .buëek, pl. i, fig. 1.se plavecké podhradie, malé karpaty (slovaquie): trias moyen, ? anisien inférieur (annabersky vapenec) 1994 physoporella dissita .bucur et al., pl. 11, fig. 2.sasca zone, caraş-severin (roumanie): anisien, pelsonien-illyrien inférieur (sasca fm, valea susara limestone member) 1994 (?) physoporella sp. cf. physoporella dissita .bucur et al., pl. 11, fig. 3.sasca zone, caraşs e v e r i n (roumanie): anisien, pelsonien-illyrien inférieur (sasca fm, valea susara limestone member) physoporella ? elegantannulata endo in endo et kanuma 1954 [cf. clavaporella elegantannulata (endo in endo et kanuma 1954) kochansky et herak 1960 ] physoporella heraki bystrický 1967 physoporella heraki var. heraki bystrický 1967 1967b physoporella heraki n. sp.bystrický, pl. ix, fig. 1-3; pl. x, fig. 1-4; pl. xi, fig. 3-4; pl. xiv, fig. 5.w silická brezová, slovenský kras (slovaquie): carnien inférieur.holotype: pl. ix, fig. 1, lame mince n° 2183, collection j. bystrick ý, geological institute, slovak academy of sciences, bratislava (slo vaquie) 1979 physoporella heraki var. h e r a k i.bystrický, pl. iii, fig. 6.vernár, nízke tatry (slovaquie): carnien, tuvalien (tisoveckalk) 1982 physoporella heraki .e. flügel & mu, pl. 8, fig. 4 pars; pl. 9, fig. 5-6.jomda, qambdo district, e xizang / tibet (chine populaire): carnien (jiapeila fm) 1986 physoporella heraki v a r . h e r a k i.bystrický, pl. v, fig. 8.silická brezová, slovenský kras (slovaquie): carnien, julien-tuvalien (andrusoporella duplicata taxon-range zone) 124 geologia croatica 53/1 physoporella heraki var. tenuipora bystrický 1967 1967b physoporella heraki v a r . tenuipora n. var.bystrický, pl. xi, fig. 1-2.w silická brezová, slovenský kras (slovaquie): carnien inférieur, ou d’après bystrický (1986): carnien, julien-tuvalien (a n d r u s o porella duplicata taxon-range zone).holotype: pl. xi, fig. 2, lame mince n° 2804, collection j. bystrický , geological institute, slovak academy of sciences, bratislava (slovaquie) physoporella intusannulata hurka 1967, nom. nud. 1957 oligoporella pilosa v a r i c a n s .bystrický, pl. v, fig. 2.silická brezová, slovenský kras (slovaquie): anisien, pelsonien 1959 oligoporella pilosa .andrusov, pl. xi, fig. 3, extrait de bystrický (1957: pl. v, fig. 2) 1964 oligoporella pilosa var. varicans .bystrický, pl. xii, fig. 6, extrait de bystrický (1957: pl. v, fig. 2) 1965 oligoporella pilosa .andrusov, fig. 32, extrait de bystrický (1957: pl. v, fig. 2) 1966 oligoporella pilosa var. varicans .miπík, pl. ii, fig. 2, extrait de bystrický (1957: pl. v, fig. 2) 1 9 6 7 (nom. nud.) physoporella intusannulata n. sp.hurka, fig. 3.a-g, 4, 6, 7.a-g, 9-10 & 11.a-e; pl. 6, fig. 1-5.bagni di piandimáia / bad maistatt, villabassa / niederdorf, pusteria / pustertal, trentino alto adige (italie): anisien, hydaspien supérieur (pragser dolomiten).type non désigné: pl. 6, fig. 1-5, lames minces n° ug1/1-ug1/45, n° ug1/16, schliffsammlung des institutes für spezielle botanik der universität tübingen (allemagne) physoporella japonica endo 1957 1957 physoporella japonica n. sp.endo, pl. 40, fig. 7-9.zenbutsuji-dani, taishaku-mura, hiba-gun, hiroshima-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie supérieure); pl. 40, fig. 1011; pl. 41, fig. 1.misaka, shinsaka-mura, jinseki-gun, hiroshima-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne).syntypes: pl. 40, fig. 7, lame mince n° 564; pl. 40, fig. 8, lame mince n° 563; pl. 40, fig. 9, lame mince n° 561; pl. 40, fig. 10; pl. 41, fig. 1, lame mince n° 494; pl. 40, fig. 11, lame mince n° 493, department of earth sciences, saitama universi ty, urawa (japon) 1959 physoporella japonica .endo, pl. 36, fig. 1 & 4.ozudani valley, nyūgawa-mura, o _ no-gun, gifu-ken, h o n s hū (japon): permien inférieur-moyen (o _ zu fm, zone à parafusulina zone à n e o s c h w a g e r i n a); pl. 36, fig. 2.hatahoko, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien inférieur (gonbō fm, zone à p a r a f u s u l i n a = zone à p s e u d o f u s u l i n a); pl. 36, fig. 3.otani, horadani valley, nyūg a w a mura, o _ no-gun, gifu-ken, honshū (japon): permien inférieur (o _ zu fm, zone à pseudofusulina) 1961a physoporella japonica .endo, pl. 4, fig. 2, extrait de endo (1957: pl. 40, fig. 7) 1961c physoporella japonica .endo, pl. 5, fig. 3-4.akiyoshi, shuhōc hō, ne mine-shi, yamaguchi-ken, honshū (japon): permien inférieur (akiyoshi limestone group, zone à pseudoschwagerina , sous-zone à triticites simplex sous-zone à pseudofusulina vulgaris ) 1963 physoporella japonica .johnson, pl. 68, fig. 2, extrait de endo (1957: pl. 40, fig. 10); pl. 68, fig. 3, extrait de endo (1957: pl. 40, fig. 9); pl. 68, fig. 4, extrait de endo (1957: pl. 40, fig. 7) 1971 physoporella japonica .ishijima et al., pl. 12, fig. 5-6; pl. 13, fig. 5.sakaishimachibun, agano-mura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur” physoporella jomdaensis e. flügel et mu 1982 1982 physoporella jomdaensis n. sp.e. flügel & mu, pl. 8, fig. 5 pars; pl. 9, fig. 3-4.jomda, qambdo district, e xizang / tibet (chine populaire): carnien (jiapeila fm).holotype: pl. 9, fig. 3, lame mince n° 76 cj 25, nanjing institute of geology and paleontology, academia sinica, nanjing (chine populaire) 1997 physoporella jomdaensis .grgasoviê, pl. ii, fig. 10 & 14-15.æumberak mt, ne kraπiê, w zagreb (croatie): norien (dolomia principale / hauptdolomit, aulotortus sinuosus interval zone) physoporella kanmerai endo 1969 1969 physoporella kanmerai n. sp.endo, pl. xxvi, fig. 6-10; pl. xxvii, fig. 1-3.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina zone à neoschwagerina simplex / partie inférieure).holotype: pl. xxvi, fig. 6, lame mince n° gk.d 13037, kyūshū university, fukuoka (japon) 125granier & grgasoviê: les algues dasycladales du permien et du trias... physoporella kitakamiensis endo 1956 1956 physoporella kitakamiensis n. sp.endo, pl. 30, fig. 5-6; pl. 31, fig. 1-4.toyomane-mura, iruma-gun, saitama-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / parties moyenne-supérieure).syntypes: pl. 30, fig. 6, lame mince n° 212; pl. 31, fig. 1-4, lames minces n° 212 & 213, department of earth sciences, saitama university, urawa (japon) 1957 physoporella kitakamiensis.endo & horiguchi, pl. xiii, fig. 1.kamitakara-mura, fukuji, gifu-ken, honshū (japon): permien inférieur (ichinotani group, zone à pseudoschwagerina ) physoporella konishii endo 1959, nom. nud. 1 9 5 9 (nom. nud.) physoporella konishii n. sp.endo, pl. 42, fig. 4-5.otani, horadani valley, nyūg a w a m u r a , o _ no-gun, gifu-ken, honshū (japon): permien inférieur (o _ zu fm, zone à p s e u d o s c h w a g e r i n a ).“holotype” (syntypes): pl. 42, fig. 4, lame mince n° 614; pl. 42, fig. 5, lame mince n° 617, department of earth sciences, saitama university, urawa (japon) 1 9 6 8 a (?) (nom. nud.) physoporella cf. k o n i s h i i.endo, pl. xxxiv, fig. 2.mindoro (philippines): permien dans conglomérat jurassique? physoporella laevis praturlon 1963 1963 physoporella laevis n. sp.praturlon, pl. iv, fig. 1-7.vallone secosta, auronzo di cadore, véneto (italie): permien supérieur (bellerophon fm / “bellerophon-zone” / partie terminale) .holotype: pl. iv, fig. 2, lame mince n° g 1/8, collection a. praturlon, micropalaeontological collection, institute of geology and palaeontology, roma (italie) 1967 physoporella laevis .accordi & broglio loriga, pl. xv, fig. 3, extrait de praturlon (1963: pl. iv, fig. 2) physoporella lativentrusa endo 1959, nom. nud. 1959 (nom. nud.) physoporella lativentrusa n. sp.endo, pl. 42, fig. 8-9.otani, horadani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien (o _ zu fm).“holotype” (syntypes): pl. 42, fig. 8, lame mince n° 611; pl. 42, fig. 9, lame mince n° 618, department of earth sciences, saitama university, urawa (japon) 1971 physoporella lativentrusa .ishijima et al., pl. 13, fig. 4.sakaishimachibun, agano-mura, hannōs h i , iruma-gun, saitama-ken, honshū (japon): permien “inférieur” physoporella leptotheca kochansky-devidé 1967 1958 physoporella lotharingica .ellenberger, fig. 11.diemtigtal, bern (suisse): ? 1967 physoporella leptotheca n. sp.kochansky-devidé, pl. i, fig. 1-12.æeleznica, n gozd-martuljek, e kranjska gora (slovénie): trias, ou d’après ramovπ in fois (1979): ? anisien supérieur.holotype: pl. i, fig. 1 pars, “oberer schnitt”, lame mince n° j 173, zbirka katedre za geologijo in paleontologijo univerze v ljubljani [sammlung des lehrstuhls für geologie und paläontologie der universität in ljubljana ], ljubljana (slovénie); paratypes: pl. i, fig. 1 pars, 5, 7 & 10, lame mince n° j 173, zbir ka katedre za geologijo in paleontologijo univerze v ljubljani [sammlung des lehrstuhls für geologie und paläontologie der universität in ljubljana ], ljubljana (slovénie); pl. i, fig. 2, lame mince n° j 174; pl. i, fig. 3-4, lame mince n° j 178; pl. i, fig. 6, lame mince n° j 175; pl. i, fig. 8 & 11, lame mince n° j 518; pl. i, fig. 9 & 12, lame mince n° j 176, tehniëki muzej [t e c h n i s c h e n museum ], jesenice (slovénie) 1979 physoporella leptotheca .fois, pl. 3, fig. 1-5 & 8; pl. 5, fig. 1-13.mte popera, rocca di campo bivacco piovan, belluno, véneto (italie): anisien, illyrien (“algal limestones”, aviasianus zone) 1983 physoporella leptotheca .fois & jadoul, pl. 1, fig. c pars, d.2 & f.1.mte bruca, n pontebba / pontafel, friuli venezia giulia (italie): anisien, illyrien (aviasianus zone, calcari nodulari inferiori) 1986 (?) physoporella leptotheca .braga, fig. 2.a-g & 2.o.sierra de baza, gor baza, granada (espagne): norien (alpujarride complex, santa barbara unit, carbonate fm, member j) 1999 (?) physoporella aff. leptotheca .parente & climaco, pl. 40, fig. 9-10.mte rotonda, e maratea, basilicata (italie): trias supérieur, norien 126 geologia croatica 53/1 physoporella likana herak in granier et deloffre 1995, non 1965 1965 (nom. nud.) physoporella likana n. sp.herak, pl. xiv, fig. 1-3.nnw peêina ponor, sv. rok, lika (croatie): trias moyen.syntypes: pl. xiv, fig. 1-3, lame mince alg. 86, geoloπko-paleontoloπki zavod, prirodoslovno-matematiëki fakultet [geological and palaeontological institute, faculty of science ], zagreb (croatie) 1973 non (nom. nud.) physoporella likana [= ? kantia dolomitica].popa & dragastan, pl. xix, fig. 73 1995 physoporella likana .herak in granier & deloffre, p. 57, non figurée.typification et validation de l’espèce; lectotype: pl. xiv, fig. 2 i n herak (1965), lame mince alg. 86, geoloπko-paleontoloπki zavod, prirodoslovno-matematiëki fakultet [geological and palaeontological institute, faculty of science], zagreb (croatie) physoporella lotharingica (benecke 1898) pia 1931 [= diplopora lotharingica benecke 1898 ] 1898 diplopora lotharingica n. sp.benecke, fig. 1.gänglingen, nw faulquemont / falkenberg, moselle (france): trias moyen.type: fig. 1 1913 diplopora lotharingica .hohenstein, pl. i, fig. 1.haiterbach, baden-württemberg (allemagne): trias moyen 1920 physoporella pauciforata var. ? lotharingica n. stat. n. comb.pia, pl. iii, fig. 11 & 13.furthof, türnitz, niederösterreich (autriche): anisien (reiflinger kalk) 1920 non physoporella pauciforata var. ? l o t h a r i n g i c a n. stat. n. comb. [= physoporella pauciforata v a r . undulata].pia, pl. iii, fig. 12 & 14 1928 physoporella pauciforata var. l o t h r i n g i a c a [s i c].schmidt, fig. 10, extrait de hohenstein (1913: pl. i, fig. 1) 1931 physoporella lotharingica n. comb.pia, pl. xxi, fig. 8.gänglingen, nw faulquemont / falkenberg, moselle (france): trias moyen (anhydritgebirge supérieur), ? ladinien 1935b (?) physoporella aff. lotharingica .pia in schmidt, pl. ii, fig. 2.prades, nw tarragona (espagne): anisien 1958 physoporella lotharingica .ellenberger, pl. 7, fig. 17-19.paroi de la porteille, forêt de sollières, montfroid, vanoise, savoie (france): ladinien (en éboulis, dolomies terminales à myophora goldfusi) 1958 non physoporella lotharingica [= physoporella leptotheca ].ellenberger, fig. 11 1965 physoporella lotharingica .herak, pl. xiv, fig. 4.debelo brdo, nw knin (croatie): ladinien supérieur; pl. xiv, fig. 5.gradina, vrkljanski ponori, sv. rok, lika (croatie): ladinien; pl. xiv, fig. 6.sekulin vrh, sw liëka kaldrma, lika (croatie): trias moyen 1968 (?) “pseudo-” physoporella lotharingica [s i c].mégard-galli, fig. 7.g-h.mte boulliagna, w acceglio, piemonte (italie): ladinien inférieur; fig. 7.e-f & i.mte boulliagna, w acceglio, piemonte (italie): ladinien moyen 1969 (?) ? physoporella sp. ou diplopora uniserialis .bloch in bloch & lefevre, pl. i, fig. 7-9.val de preit, bric bernoir, col del mulo-passo della gardetta, bersezio, piemonte (italie): ladinien 1973 non physoporella lotharingica [= ? oligoporella chia ].popa & dragastan, pl. xix, fig. 77 1979 dasicladacee.de castro, pl. xvii, fig. 3 & 5-10.il castello, s marsico nuevo, basilicata (italie): trias moyen 1997 physoporella lotharingica .pugliese, pl. 1, fig. 10-13.mte toff, n tione di trento, gruppo di brenta, trentino alto adige (italie): ladinien physoporella minutula (gümbel 1872) pia 1912 [= clavaphysoporella minutula (gümbel 1872) endo 1958; = gyroporella minutula gümbel 1872 ] 1872 gyroporella minutula n. sp.gümbel, pl. d.iii, fig. 4.a-b.reisalpe, niederösterreich (autriche): trias moyen (reiflinger kalk) et/ou pertisau, achensee, tirol (autriche) .types: pl. d.iii, fig. 4.a-b, collec tion c.w. gümbel (coll. prof. pichler), münchen (allemagne) 1872 (?) ? gyroporella minutula .gümbel, pl. d.iii, fig. 5.a-b.jemielnica / himmelwitz, ne strzelce opolskie, haute silésie (pologne): trias moyen 1912 physoporella minutula n. comb.pia, pl. vi(v), fig. 5-10 & 12.mythen, zweckenalp, schwyz (suisse): trias ? moyen (wettersteinkalk) 127granier & grgasoviê: les algues dasycladales du permien et du trias... 1912 (?) physoporella minutula n. comb. [= ? oligoporella pilosa v a r . p i l o s a].pia, pl. vi(v), fig. 11.mythen, zweckenalp, schwyz (suisse): trias ? moyen (wettersteinkalk) 1920 physoporella minutula .pia, pl. ii, fig. 19-22.zweckenalp, schwyz (suisse): trias moyen, ? anisien 1928 gyroporella cf. minutula.schmidt, fig. 11.b-c, extrait de gümbel (1874: pl. d.iii, fig. 4.a-b) 1957 (?) physoporella cf. minutula.bystrický, pl. vi, fig. 8.silická planina, slovenský kras (slovaquie); pl. vi, fig. 9.e berc, pleπivecká planina, slovenský kras (slovaquie) 1958 physoporella minutula.ellenberger, pl. 6, fig. 18-19.roc de la pêche, vanoise, savoie (france): “virglorien” (anisien) supérieur 1958 clavaphysoporella minutula n. gen. n. comb.endo, p. 266, non figurée 1960 diplopora cf. s i l e s i a c a .pastwa-leszczyńska & śl i w iński, fig. 7; pl. iii, fig. 13 [= fig. 7].ka̧ t y (rosowa góra), nw chrzanów, haute silésie (pologne): anisien 1961 physoporella minutula.botteron, pl. vi, fig. 4 pars.mont d’or, vaud (suisse): “virglorien” (anisien) supérieur 1964 physoporella cf. minutula.bystrický, pl. xx, fig. 4.skalica, w gemerská hôrka, w pleπivec, planina koniart, slovenský kras (slovaquie): anisien, illyrien inférieur 1964 (?) physoporella cf. minutula.bystrický, pl. xx, fig. 5.horný vrch, slovenský kras (slovaquie): anisien, illyrien inférieur; pl. xxi, fig. 10.w rakotá, silická planina, slovenský kras (slovaquie): anisien, illyrien inférieur 1965 p h y s o p o r e l l a cf. m i n u t u l a.bystrický & veizer, pl. iii, fig. 5.»ervené vrchy, vysoke tatry (slovaquie): anisien 1965 non physoporella cf. minutula [= physoporella minutuloidea ].herak, pl. xii, fig. 3 1965 non physoporella minutula [= ? physoporella minutuloidea ].herak, pl. xii, fig. 6 1968 non physoporella minutula [= ? placklesia multipora ]bilgütay, pl. iii, fig. 10 1968 non physoporella minutula [= diplopora tubispora ].bilgütay, pl. iii, fig. 11 1969 physoporella minutula .diaconu & dragastan, pl. iv, fig. 7-8.dealul glimeia, apuseni mts (roumanie): anisien supérieur 1970 p h y s o p o r e l l a m i n u t u l a.patrulius, pl. i, fig. 9; pl. ii, fig. 3-5; pl. v, fig. 6.valea lupşa, perşani mts, braşov (roumanie): anisien, pelsonien-illyrien inférieur 1971 (?) physoporella minutula .zorn, pl. 17, fig. 2.mte san salvatore, s lugano, ticino (suisse): ladinien (oberer salvatoredolomit) 1972 p h y s o p o r e l l a d i s s i t a .bleahu et al., pl. iv, fig. 1.vaşcǎu plateau, apuseni mts, bihor (roumanie): anisien moyen-supérieur 1973 (?) physoporella minutula .kotański & »atalov, pl. ix, fig. 1-35.staneto, s troyan, loveë (bulgarie): anisien, pelsonien 1973 (?) physoporella minutula .popa & dragastan, pl. vi, fig. 21 pars; pl. x, fig. 38 & 39 pars.w lorǎu, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à dadocrinus communis); pl. vii, fig. 28; pl. viii, fig. 30 pars; pl. xv, fig. 57 pars; pl. xvi, fig. 63 pars.e lorǎu, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à dadocrinus communis); pl. x, fig. 37; pl. xiv, fig. 55 pars.e vǎii iadului, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à dadocrinus com munis) 1973 physoporella pauciforata .popa & dragastan, pl. vi, fig. 24.e lorǎu, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à dadocrinus communis) 1975 physoporella minutula .dragastan & grǎdinaru, pl. iv, fig. 25; pl. vi pars.s dunavát, tulcea (roumanie): anisien, pelsonien-illyrien inférieur 1979 physoporella minutula .kotański, pl. 79, fig. 11-12.tatry (pologne): anisien, illyrien 1980 physoporella minutula .dragastan, pl. iii, fig. 8.valea saratii, perşani mts, braşov (roumanie): anisien moyen 1980 (?) physoporella minutula .dragastan, pl. iv, fig. 8 pars, extrait de popa & dragastan (1973: pl. xv, fig. 57) 1986 physoporella minutula .kotański, pl. ciii, fig. 11-12, extrait de kotański (1979: pl. 79, fig. 11-12); pl. cv, fig. 20-21.forage winowno 25 ww, winowno, siewierz kozieglowy, haute silésie (pologne): anisien, pelsonien 128 geologia croatica 53/1 1988 clavaphysoporella gyroporella minutula .deloffre, pl. 5, fig. 9, extrait de pia (1920: pl. ii, fig. 20); pl. 5, fig. 10, extrait de pia (1920: pl. ii, fig. 22) 1994 non physoporella minutula [= ? physoporella pauciforata var. sulcata ].bucur et al., pl. 10, fig. 3 pars & 4; pl. 11, fig. 4-7 & 19 pars 1994 (?) physoporella cf. m i n u t u l a.e. flügel et al., pl. 2, fig. 4.bled (slovénie): anisien, ? ‘aegean’ pelsonien physoporella minutuloidea herak 1967 1965 p h y s o p o r e l l a cf. m i n u t u l a.herak, pl. xii, fig. 3.deralo, bosansko grahovo (bosnie-herzégovine): anisien 1965 (?) p h y s o p o r e l l a m i n u t u l a.herak, pl. xii, fig. 6.wsw klanac pucaloviêa, sv. rok, lika (croatie): anisien 1967a physoporella minutuloidea n. sp.herak, pl. 9, fig. 1.ligaridi, khíos / chios (grèce): anisien.holotype: pl. 9, fig. 1, lame mince n° t219/4, collection k.-w. tietze, geologisch-paläontologischen institut der universität marburg (allemagne) physoporella nyugawensis endo 1959 1959 physoporella nyugawensis n. sp.endo, pl. 35, fig. 9.ozudani valley, nyūgawa-mura, o _ no-gun, gifuken, honshū (japon): permien inférieur-moyen (o _ zu fm, zone à parafusulina zone à neoschwagerina); pl. 35, fig. 10; pl. 40, fig. 2.odani, horadani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien inférieur (o _ zu fm, zone à p s e u d o f u s u l i n a).holotype: pl. 35, fig. 9, lame mince n° 21126, geol. min. inst., tokyo kyoiku daigaku [tokyo university of education ] (japon) physoporella ovata endo 1961 1961b physoporella ovata n. sp.endo, pl. 15, fig. 1.sukawa, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 16, fig. 1; pl. 17, fig. 6.w nagaoka, santō-machi, sakatagun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 17, fig. 5.e o _ nogi, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien “moyen” / partie inférieure (o _ nogi fm).holotype: pl. 16, fig. 1, lame mince n° 510605-1, geological survey of japan (japon) 1963 physoporella ovata .johnson, pl. 68, fig. 5, extrait de endo (1961b: pl. 17, fig. 6) 1969 physoporella ovata .endo, pl. xxiv, fig. 8-10; pl. xxv, fig. 7-9.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina ) 1971 physoporella ovata .ishijima et al., pl. 13, fig. 2-3.sakaishimachibun, agano-mura, hannō-shi, irumagun, saitama-ken, honshū (japon): permien “inférieur” *physoporella pauciforata (gümbel 1872) steinmann 1903, emend. pia 1912 [= gyroporella pauciforata gümbel 1872 ] physoporella pauciforata var. gemerica bystrický 1962 1962 physoporella pauciforata var. gemerica n. var.bystrický, pl. iv, fig. 4-5.ne tornánadaska, s dolný vrch, aggteleki-karszt (hongrie): anisien, pelsonien-illyrien inférieur.holotype: pl. iv, fig. 4, lame mince n° pë-109, collection j. bystricky ´, geologický prieskum, n.p. æilina (slovaquie) 1964 physoporella pauciforata var. g e m e r i c a .bystrický, pl. xvi, fig. 1, extrait de bystrický (1962: pl. iv, fig. 5); pl. xvi, fig. 2.maloldal, keëovo, se pleπivec, slovenský kras (slovaquie): anisien, pelsonienillyrien inférieur; pl. xvi, fig. 3.zakázané, silická planina, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur; pl. xvi, fig. 4, extrait de bystrický (1962: pl. iv, fig. 4); pl. xvi, fig. 5.s l o v e n s ký kras (slovaquie): anisien, pelsonien-illyrien inférieur; pl. xxxiv, fig. 2 pars.dlhá lúka, silická planina, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur ou, d’après bystrický (1966): anisien, pelsonien 1964 physoporella pauciforata v a r . g e m e r i c a .dieni & spagnulo, pl. ii, fig. 4-5.mte corona, dosso dei morti, se adamello, trentino alto adige (italie): anisien 1965 (?) physoporella pauciforata cf. var. gemerica.herak, pl. xiii, fig. 3.deralo, bosansko grahovo (bosnieherzégovine): anisien 129granier & grgasoviê: les algues dasycladales du permien et du trias... 1966 physoporella pauciforata var. gemerica.bystrický, pl. vii, fig. 5.ponická lehôtka poniky oravce postredná môlëa, e banská bystrica (slovaquie): anisien, pelsonien (steinalmkalk) 1966 physoporella pauciforata var. g e m e r i c a .miπík, pl. ii, fig. 1 pars, extrait de bystrický (1964: pl. xxxiv, fig. 2 pars) 1967a (?) physoporella pauciforata cf. gemerica.bystrický, pl. ii, fig. 1.predajná, w brezno, nízke tatry (slovaquie): anisien supérieur (choë-dolomit) 1967b physoporella pauciforata var. g e m e r i c a.herak, pl. 1, fig. 7.loßeck, gosaukamm, dachsteingruppe, oberösterreich (autriche): anisien (massenkalk) 1967b (?) physoporella pauciforata (?) var. g e m e r i c a .herak, pl. 1, fig. 6.loßeck, gosaukamm, dachsteingruppe, oberösterreich (autriche): anisien (massenkalk) 1970 physoporella pauciforrata var. g e m e r i c a [s i c].papp & turnowski (herak), pl. 9 pars.sw gosaukamm, dachsteingruppe, salzburg (autriche): anisien (massenkalk) 1973 non physoporella pauciforata var. gemerica [= ? oligoporella pilosa var. intusannulata ].popa & dragastan, pl. iv, fig. 16 pars; pl. v, fig. 19 pars; pl. x, fig. 40; pl. xi, fig. 41 1973 non physoporella pauciforata var. g e m e r i c a [= physoporella pauciforata var. s u l c a t a ].popa & dragastan, pl. viii, fig. 32 1982 physoporella pauciforata var. g e m e r i c a .casati et al., pl. 35, fig. (3 &) 9.col vidàl, s auronzo di cadore, véneto (italie): anisien, pelsonien ? illyrien (fm del serla superiore) 1986 physoporella pauciforata var. g e m e r i c a.bystrický, pl. ii, fig. 1.dolný vrch, slovenský kras (slovaquie): anisien, bithynien-illyrien inférieur (physoporella pauciforata oligoporella pilosa a s s e mblage zone) fig. 20 physoporella pauciforata cf. var. gemerica (herak, 1965, pl. xiii, fig. 3), x19. fig. 21 physoporella pauciforata var. simplex (herak, 1965, pl. xiii, fig. 5), x19. 130 geologia croatica 53/1 1989 physoporella pauciforata v a r . g e m e r i c a.buëek, pl. ii, fig. 2.w zárub, malé karpaty (slovaquie): anisien, pelsonien-illyrien inférieur (steinalmkalk) physoporella pauciforata var. pauciforata pia ex bystricky´ 1964 [= var. simplex pia 1935, nom. nud. ] 1872 gyroporella pauciforata n. sp.gümbel, pl. d.iii, fig. 2.a-f.reisalpe, niederösterreich (autriche): trias moyen (reiflinger kalk) et/ou pertisau, achensee, tirol (autriche).types: pl. d.iii, fig. 2.a-e, collec tion c.w. gümbel (coll. prof. pichler), münchen (allemagne) 1872 (?) ? gyroporella pauciforata .gümbel, pl. d.iii, fig. 3.a-b.haute silésie (pologne): trias moyen 1903 physoporella pauciforata n. comb.steinmann, p. 50, non figurée 1907 non physoporella pauciforata .steinmann, fig. 9.a-b.braies / prags, pusteria / pustertal, trentino alto adige (italie): trias moyen 1912 physoporella pauciforata emend.pia, pl. v(iv), fig. 9-11.n brandmäuer, puchenstuben, niederösterreich (autriche): trias moyen; pl. v(iv), fig. 13-16.schwarzenberg, w türnitz, niederösterreich (autriche): trias moyen; pl. v(iv), fig. 17.neßlinger wand, krimml, salzburg (autriche): trias moyen; pl. v(iv), fig. 19.sarenkofel, susch / süs, unter-engadin, graubünden (suisse): trias moyen 1912 (?) physoporella pauciforata [= ? physoporella pauciforata var. sulcata].pia, pl. v(iv), fig. 12.n brandmäuer, puchenstuben, niederösterreich (autriche): trias moyen 1912 non physoporella pauciforata [= oligoporella prisca ].pia, pl. v(iv), fig. 18 1920 physoporella pauciforata .pia, pl. iii, fig. 10 & 15.mte serla / sarlkofel, se villabassa / niederdorf, pusteria / pustertal, trentino alto adige (italie): anisien (en éboulis, mendoladolomit) 1927 physoporella pauciforata .ogilvie gordon, pl. ix, fig. 5.sasso lungo / langkofel, santa cristina / st. christina, val gardena / grödnertal, trentino alto adige (italie): trias moyen (mendoladolomit); pl. x, fig. 4.a-b; pl. xiii, fig. 7.a-b.val di fassa, trentino alto adige (italie): trias moyen (mendolakalk) 1935a (nom. nud.) physoporella pauciforata var. simplexn. var.pia, p. 223, non figurée .choix de néotypes: pl. v(iv), fig. 13 in pia (1912), lame mince n° xxviii/1; pl. v(iv), fig. 14-16 in pia (1912), lame mince n° xxviii/2, collection j. von pia, naturhistorisches museum, wien (autriche) 1957 (nom. nud.) physoporella pauciforata simplex.bystrický, pl. vi, fig. 1.n hosúsov, szárosz-szoba, silická planina, slovenský kras (slovaquie): anisien (? moyen-) supérieur; pl. vi, fig. 2.kolísky, stratenská hornatina mts (slovaquie): anisien (? moyen-) supérieur 1958 physoporella pauciforata .herak, pl. 13, fig. 1-5.skubrov vrh, jezersko (slovénie): anisien 1964 physoporella pauciforata var. pauciforata n. var.bystrický, pl. xiii, fig. 1.kamenec, s dlhá ves, se pleπivec, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur; pl. xiii, fig. 2.szárosz-szoba, silická planina, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur, ou d’après b y s t r i c ký (1986): anisien, bythinien-illyrien inférieur (physoporella pauciforata oligoporella pilosa assemblage zone); pl. xiii, fig. 3.zakázané, silická planina, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur; pl. xiii, fig. 4-5; pl. xiv, fig. 6; pl. xv, fig. 6.rakotá, silická planina, s l o v e n s ký kras (slovaquie): anisien, pelsonien-illyrien inférieur; pl. xiii, fig. 6; pl. xv, fig. 4.s vëeláre, dolný vrch, slovenský kras (hongrie): anisien, pelsonien-illyrien inférieur; pl. xiv, fig. 3-4.l i p o v n i ë ký salaπ, soroπka, horný vrch, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur; pl. xiv, fig. 5; pl. xv, fig. 5.b.silická planina, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur; pl. xxxiv, fig. 2 pars.dlhá lúka, silická planina, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur, ou d’après bystrický (1966): anisien, pelsonien 1965 physoporella pauciforata var. pauciforata .assereto et al., pl. 80, fig. 1-3; pl. 81, fig. 3.w castelfranco, val gola / val camónica, ne bergamo, lombardia (italie): anisien (calcare di camorelli) 1965 physoporella pauciforata .herak, pl. ix, fig. 1.b.plavno, pleπivica, nw knin (croatie): anisien 1 9 6 5 (nom. nud.) physoporella pauciforata var. s i m p l e x.herak, pl. xiii, fig. 5.plavno, pleπivica, nw knin (croatie): anisien 1966 physoporella pauciforata var. p a u c i f o r a t a .miπík, pl. ii, fig. 1 pars, extrait de bystrický (1964: pl. xxxiv, fig. 2 pars) 1967a physoporella pauciforata var. p a u c i f o r a t a .bystrický, pl. i, fig. 1.predajná, w brezno, nízke tatry (slovaquie): anisien supérieur (choë-dolomit) 1967a physoporella pauciforata .herak, pl. 8, fig. 5.ligaridi, khíos / chios (grèce): anisien 131granier & grgasoviê: les algues dasycladales du permien et du trias... 1967b physoporella pauciforata var. p a u c i f o r a t a .herak, pl. 1, fig. 2; pl. 2, fig. 1.loßeck, gosaukamm, dachsteingruppe, oberösterreich (autriche): anisien (massenkalk) 1969 physoporella-oligoporella .hurka, fig. 2.a; fig. 3.g-h & 3.l-r; fig. 4.f; fig. 5.w; fig. 7.1.mte serla / sarlkofel, se villabassa / niederdorf, pusteria / pustertal, trentino alto adige (italie): anisien (oberer sarldolomit) 1969 (?) p h y s o p o r e l l a o l i g o p o r e l l a .hurka, fig. 5.a-h & 5.l-v; fig. 7.2-6 & 7.9.mte serla / sarlkofel, se villabassa / niederdorf, pusteria / pustertal, trentino alto adige (italie): anisien (oberer sarldolomit) 1970 physoporella pauciferrata [s i c].papp & turnovsky (herak), pl. 10 pars.sw gosaukamm, dachsteingruppe, salzburg (autriche): anisien (massenkalk) 1970 non physoporella pauciferrata [sic; = ? physoporella dissita ].papp & turnovsky (herak), pl. 11 1972 physoporella pauciforata var. p a u c i f o r a t a .bleahu et al., pl. i, fig. 1-3.vaşcǎu plateau, apuseni mts, bihor (roumanie): anisien moyen-supérieur 1972 physoporella praealpina .bleahu et al., pl. iii, fig. 3-4.vaşcǎu plateau, apuseni mts, bihor (roumanie): anisien moyen-supérieur 1972 (?) p h y s o p o r e l l a cf. pauciforata pauciforata .»anoviê & kemenci, pl. i, fig. 5 & 7.forage golubinci-1 (gb-1), e ruma, vojvodina, serbie (yougoslavie): anisien (zone à rhynchonella decurtata) 1973 physoporella pauciforata var. p a u c i f o r a t a .kotański & »atalov, pl. x, fig. 1-6.staneto, s troyan, loveë (bulgarie): anisien, pelsonien 1973 oligoporella cf. prisca .popa & dragastan, pl. viii, fig. 31.e lorǎu, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à dadocrinus communis) 1973 physoporella pauciforata .popa & dragastan, pl. iv, fig. 14-15 & 16 pars.e vǎii iadului, e pǎd u r e a craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à d a d o c r i n u s c o m m u n i s); pl. vii, fig. 25, 26 pars & 27.e lorǎu, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à dadocrinus communis) 1973 (?) physoporella pauciforata .popa & dragastan, pl. iv, fig. 13; pl. v, fig. 17.e vǎii iadului, e pǎd u r e a craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à d a d o c r i n u s c o m m u n i s); pl. vi, fig. 21 pars & 22-23; pl. xiii, fig. 49 pars, 50 pars, 51 pars & 52 pars.e lorǎu, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à dadocrinus communis); pl. xiv, fig. 56.w vǎii iadului, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à dadocrinus communis) 1973 non physoporella pauciforata [= physoporella minutula ].popa & dragastan, pl. vi, fig. 24 1974 physoporella pauciforata var. p a u c i f o r a t a .mello, pl. i, fig. 3 pars.s roæňava, slovenský kras (slovaquie): anisien, pelsonien-illyrien (steinalmkalk) 1975 physoporella pauciforata .dragastan & grǎdinaru, pl. iv, fig. 24.s dunavát, tulcea (roumanie): anisien, pelsonien-illyrien inférieur 1976 (?) physoporella oligoporella .epting et al., fig. 6 pars.dosso dei morti, se adamello, nw valli giudicárie, trentino alto adige (italie): anisien moyen (dosso dei morti limestone / partie sommitale) 1980 physoporella pauciforata .dragastan, pl. iv, fig. 2, extrait de popa & dragastan (1973: pl. vii, fig. 25 pars); pl. iv, fig. 3, extrait de popa & dragastan (1973: pl. viii, fig. 31); pl. iv, fig. 6, extrait de popa & dragastan (1973: pl. iv, fig. 16 pars); pl. iv, fig. 7, extrait de popa & dragastan (1973: pl. iv, fig. 14) 1980 dasycladaceae.farabegoli & guasti, pl. 65, fig. 1.mte rite, w cibiana di cadore, sw pieve di cadore, véneto (italie): anisien, pelsonien (fm del serla superiore) 1982 physoporella pauciforata var. pauciforata .casati et al., pl. 35, fig. 1 pars, 2.a & 6.col vidàl, s auronzo di cadore, véneto (italie): anisien, pelsonien ? illyrien (fm del serla superiore) 1986 physoporella pauciforata var. p a u c i f o r a t a .bystrický, pl. ii, fig. 2, extrait de bystrický (1964: pl. xiii, fig. 2) 1986 physoporella pauciforata .kotański, pl. cvi, fig. 9.b.forage krusin 23 ww, krusin, siewierz kozieglowy, haute silésie (pologne): anisien, pelsonien 1987 (?) physoporella cf. pauciforata .strutinski et al., pl. ii, fig. 2.sasca montana, caraş-severin (roumanie): anisien, pelsonien-illyrien inférieur 1988 physoporella pauciforata pauciforata .»anoviê & kemenci, pl. iv, fig. 1, extrait de »anoviê & kemenci (1972: pl. i, fig. 5) 1989 physoporella pauciforata var. pauciforata .buëek, pl. ii, fig. 1.nw vrátna, malé karpaty (slovaquie): anisien, pelsonien-illyrien inférieur (steinalmkalk) 132 geologia croatica 53/1 1989 physoporella pauciforata .gaetani & gorza, pl. 10, fig. 4.lóvere, val gola / val camónica, ne bergamo, lombardia (italie): anisien (calcare di camorelli) 1993 dasycladacean skeletal fragments.budai, lelkes & piros, pl. iii, fig. 3.forage drt. 1, dörgicse, veszprém, balaton (hongrie): anisien (tagyon limestone fm) 1993 physoporella pauciforata pauciforata .budai, lelkes & piros, pl. v, fig. 2.forage szentantalfa 1 (szaf. 1), veszprém, balaton (hongrie): anisien (tagyon limestone fm) 1993 non physoporella pauciforata pauciforata [= physoporella pauciforata var. sulcata ].budai, lelkes & piros, pl. v, fig. 1 1994 physoporella pauciforata .bucur et al., pl. 11, fig. 8-9 & 11.sasca zone, caraş-severin (roumanie): anisien, pelsonien-illyrien inférieur (sasca fm, valea susara limestone member) 1994 (?) physoporella cf. pauciforata .e. flügel et al., pl. 1, fig. 10.bled (slovénie): anisien, ? ‘aegean’ pelsonien physoporella pauciforata var. simplex pia 1935, nom. nud. [cf. physoporella pauciforata var. pauciforata pia ex bystricky´ 1964] physoporella pauciforata var. sulcata bystrický 1962 1912 (?) physoporella pauciforata .pia, pl. v(iv), fig. 12.n brandmäuer, puchenstuben, niederösterreich (autriche): trias moyen 1962 physoporella pauciforata var. s u l c a t a n. var.bystrický, pl. iv, fig. 2 & 6.rakotá, silická planina, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur; pl. iv, fig. 3.rakotá, silická planina, ou d’après bystrický (1964): berc, pleπivecká planina, slovenský kras (slovaquie): anisien, pelsonien illyrien inférieur, ou d’après bystrický (1986): anisien, bythinien-illyrien inférieur (physoporella pauci forata oligoporella pilosa assemblage zone).holotype: pl. iv, fig. 2, lame mince n° m-5513/59, collection j. bystricky´, geologický ústav dioný za ©túra, bratislava (slovaquie) 1964 physoporella pauciforata var. s u l c a t a .bystrický, pl. xiv, fig. 1.szárosz-szoba, silická planina, s l o v e n s ký kras (slovaquie): anisien, pelsonien-illyrien inférieur; pl. xiv, fig. 2.w rakotá, silická planina, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur; pl. xv, fig. 1, extrait de bystrický (1962: pl. iv, fig. 3); pl. xv, fig. 2, extrait de bystrický (1962: pl. iv, fig. 2); pl. xv, fig. 3 & 5.a.silica, silická planina, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur 1964 physoporella pauciforata var. sulcata .dieni & spagnulo, pl. ii, fig. 1-2.mte corona, dosso dei morti, se adamello, nw valli giudicárie, trentino alto adige (italie): anisien 1967a (?) physoporella pauciforata cf. var. s u l c a t a .bystrický, pl. i, fig. 2.predajná, w brezno, nízke tatry (slovaquie): anisien supérieur (choë-dolomit) 1967b physoporella pauciforata var. s u l c a t a .herak, pl. 1, fig. 1 & 3-5; pl. 3, fig. 4.loßeck, gosaukamm, dachsteingruppe, oberösterreich (autriche): anisien (massenkalk) 1969 non physoporella pauciforata var. s u l c a t a .diaconu & dragastan, pl. iv, fig. 4-5.dealul glimeia, apuseni mts (roumanie): anisien supérieur 1969 physoporella-oligoporella .hurka, fig. 3.a-f & 3.j.mte serla / sarlkofel, se villabassa / niederdorf, pusteria / pustertal, trentino alto adige (italie): anisien (oberer sarldolomit) 1970 physoporella pauciforata var. sulcata .pantiê, pl. x, fig. 1-4.ædrelo, e serbie (yougoslavie): anisien, pelsonien (“zone avec rhynchonella decurtata”) 1970 physoporella pauciferata var. s u l c a t a [s i c].papp & turnovsky (herak), pl. 8.sw gosaukamm, dachsteingruppe, salzburg (autriche): anisien (massenkalk) 1972 physoporella pauciforata var. s u l c a t a .bleahu et al., pl. i, fig. 4; pl. ii, fig. 1-3.vaşcǎu plateau, apuseni mts, bihor (roumanie): anisien moyen-supérieur 1972 physoporella varicans .bleahu et al., pl. iii, fig. 5.vaşcǎu plateau, apuseni mts, bihor (roumanie): anisien moyen-supérieur 1973 (?) physoporella pauciforata var. sulcata .kotański & »atalov, pl. xi, fig. 1-15.staneto, s troyan, loveë (bulgarie): anisien, pelsonien 1973 (?) physoporella pauciforata var. s u l c a t a .popa & dragastan, pl. xv, fig. 59.w vǎii iadului, e pǎd u r e a craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à d a d o c r i n u s communis) 133granier & grgasoviê: les algues dasycladales du permien et du trias... 1973 physoporella pauciforata .popa & dragastan, pl. viii, fig. 29 pars & 30 pars; pl. xiv, fig. 53-54.w vǎii iadului, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à dadocrinus communis) 1973 physoporella pauciforata var. gemerica.popa & dragastan, pl. viii, fig. 32.e lorǎu, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à dadocrinus com munis) 1975 physoporella pauciforata var. s u l c a t a .dragastan & grǎdinaru, pl. iii, fig. 19.s dunavát, tulcea (roumanie): anisien, pelsonien-illyrien inférieur 1980 physoporella sulcata [s i c].dragastan, pl. iv, fig. 11.valea bratcutei, pǎdurea craiului, apuseni mts, bihor (roumanie): anisien moyen 1980 non physoporella pauciforata var. sulcata .dragastan, pl. vi, fig. 12, extrait de diaconu & dragastan (1969: pl. iv, fig. 4) 1981 p h y s o p o r e l l a .gaetani et al., fig. 3 pars.col vidàl, s auronzo di cadore, véneto (italie): anisien supérieur (fm del serla superiore) 1982 physoporella pauciforata var. s u l c a t a .casati et al., pl. 35, fig. 2.b & 7.col vidàl, s auronzo di cadore, véneto (italie): anisien, pelsonien ? illyrien (fm del serla superiore) 1986 physoporella pauciforata var. sulcata .bystrický, pl. i, fig. 10, extrait de bystrický (1962: pl. iv, fig. 3); pl. ii, fig. 5.szárosz-szoba, silická planina, slovenský kras (slovaquie): anisien, bithynien-illyrien inférieur (physoporella pauciforata oligoporella pilosa assemblage zone) 1987 (?) dasycladacea.oravecz-scheffer, pl. xxv, fig. 4.forage szentantalfa 1 (szaf. 1), veszprém, balaton (hongrie): anisien, illyrien (tagyon limestone formation) 1988b physoporella pauciforata sulcata .haas et al., pl. iii, fig. 2.forage som-1, ságvár, somogy, e balaton (hongrie): anisien moyen-supérieur 1989 physoporella pauciforata v a r . s u l c a t a .buëek, pl. ii, fig. 3.nw vrátna, malé karpaty (slovaquie): anisien, pelsonien-illyrien inférieur (steinalmkalk) 1993 physoporella puciforata sulcata [s i c].bérczi-makk et al., pl. viii, fig. 2, extrait de haas et al. (1988b: pl. iii, fig. 2) 1993 physoporella pauciforata pauciforata .budai, lelkes & piros, pl. v, fig. 1.forage szentantalfa 1 (szaf. 1), veszprém, balaton (hongrie): anisien (tagyon limestone fm) 1993 physoporella pauciforata sulcata .budai, lelkes & piros, pl. vi, fig. 3.forage szentantalfa 1 (szaf. 1), veszprém, balaton (hongrie): anisien (tagyon limestone fm) 1994 (?) physoporella minutula .bucur et al., pl. 10, fig. 3 pars & 4; pl. 11, fig. 4-7 & 19 pars.sasca zone, c a r aş-severin (roumanie): anisien, pelsonien-illyrien inférieur (sasca fm, valea susara limestone member) physoporella pauciforata var. undulata pia 1935 1920 physoporella pauciforata var. ? l o t h a r i n g i c a n. stat. n. comb.pia, pl. iii, fig. 12 & 14.se studeno brdo, trebeviê, sarajevo (bosnie-herzégovine): anisien 1935a physoporella pauciforata v a r . u n d u l a t a n. var.pia, fig. 33.nw blizanac, trebeviê, s sarajevo (bosnie-herzégovine): anisien, pelsonien ? illyrien (bulogkalk); fig. 34.trebeviê, sarajevo (bosnieherzégovine): anisien.types: fig. 33, lame mince n° 555a/6; fig. 34, lame mince n° 561a/5, collection j. von pia, naturhistorisches museum, wien (autriche) 1935 physoporella pauciforata var. undulata .ogilvie gordon, pl. v, fig. 1.w pieve di cadore, véneto (italie): trias moyen (mendoladolomit) 1957 physoporella pauciforata undulata .bystrický, pl. vi, fig. 3.silická planina, slovenský kras (slovaquie): anisien, pelsonien; pl. vi, fig. 4.jovice, silická planina, slovenský kras (slovaquie): anisien, pelsonien, ou d’après bystrický (1986): anisien, bithynien-illyrien inférieur (physoporella pauciforata oligoporella pilosa assemblage zone) 1964 physoporella pauciforata v a r . u n d u l a t a .bystrický, pl. xvii, fig. 1-2.w silická brezová, slovenský kras (slovaquie): anisien, pelsonien ? illyrien inférieur; pl. xvii, fig. 3.havrová, planina koniart, s l o v e n s ký kras (slovaquie): anisien, pelsonien ? illyrien inférieur; pl. xvii, fig. 4-6.e brzotín, ne pleπivec, slovenský kras (slovaquie): anisien, pelsonien ? illyrien inférieur 1964 physoporella pauciforata v a r . u n d u l a t a .dieni & spagnulo, pl. ii, fig. 3 & 6.mte corona, dosso dei morti, se adamello, nw valli giudicárie, trentino alto adige (italie): anisien 134 geologia croatica 53/1 1965 (?) physoporella pauciforata v a r . u n d u l a t a .herak, pl. xii, fig. 4.plavno, pleπivica, nw knin (croatie): anisien 1965a physoporella pauciforata var. undulata .zanin buri, pl. 49, fig. 2.b & 4-5.valle dei grassi lunghi, w pasturo, valsassina, e lago di como, lombardia (italie): anisien inférieur (fm dei calcari de recoaro, niveau à dadocrinus gracilis ) 1967a physoporella pauciforata v a r . u n d u l a t a .bystrický, pl. i, fig. 3-4.predajná, w brezno, nízke tatry (slovaquie): anisien supérieur (choë-dolomit) 1967a physoporella pauciforata var. undulata .herak, pl. 8, fig. 6.ligaridi, khíos / chios (grèce): anisien 1969 non physoporella pauciforata v a r . u n d u l a t a .diaconu & dragastan, pl. iv, fig. 3.dealul glimeia, apuseni mts (roumanie): ladinien 1969 p h y s o p o r e l l a o l i g o p o r e l l a .hurka, fig. 2.b-c; fig. 3.k & 3.s-t; fig. 4.a-c & 4.k.mte serla / sarlkofel, se villabassa / niederdorf, pusteria / pustertal, trentino alto adige (italie): anisien (oberer sarldolomit) 1969 (?) p h y s o p o r e l l a o l i g o p o r e l l a .hurka, fig. 5.j-k & 5.x-y.mte serla / sarlkofel, se villabassa / niederdorf, pusteria / pustertal, trentino alto adige (italie): anisien (oberer sarldolomit) 1972 (?) physoporella pauciforata var. u n d u l a t a .bleahu et al., pl. iii, fig. 1-2.vaşcǎu plateau, apuseni mts, bihor (roumanie): anisien moyen-supérieur 1973 (?) physoporella pauciforata v a r . u n d u l a t a .kotański & »atalov, pl. x, fig. 12-17.staneto, s troyan, loveë (bulgarie): anisien, pelsonien 1978 (?) physoporella pauciforata v a r . u n d u l a t a .anelkoviê, pl. lxv, fig. 2, extrait de herak (1965: pl. xii, fig. 4) 1980 physoporella pauciforata var. u n d u l a t a .dragastan, pl. iii, fig. 7.valea saratii, perşani mts, braşo v (roumanie): anisien moyen; pl. vi, fig. 9.brǎtcuţa, pǎdurea craiului, apuseni mts, bihor (roumanie): anisien supérieur 1983 physoporella pauciforata var. u n d u l a t a .bystrický, pl. iii, fig. 17; pl. iv, fig. 20-22; pl. v, fig. 23.e brzotín, ne pleπivec, slovenský kras (slovaquie): anisien (steinalmkalk).choix d’un lectotype: fig. 34 in pia (1935a), lame mince n° 561a/5, collection j. von pia, naturhistorisches museum, wien (autriche) 1986 physoporella pauciforata var. u n d u l a t a .bystrický, pl. ii, fig. 3., extrait de bystrický (1957: pl. vi, fig. 4) 1988 physoporella .sartorio & venturini, p. 53 bas pars, extrait de zanin buri (1965a: pl. 49, fig. 2.b) 1993 physoporella pauciforata undulata .budai, lelkes & piros, pl. v, fig. 3.forage szentantalfa 1 (szaf. 1), veszprém, balaton (hongrie): anisien (tagyon limestone fm) 1993 non physoporella pauciforata undulata [= oligoporella pilosa var. pilosa].budai, lelkes & piros, pl. v, fig. 4 1993 p h y s o p o r e l l a .budai, lelkes & piros, pl. vi, fig. 4 pars.forage drt. 1, dörgicse, veszprém, balaton (hongrie): anisien (tagyon limestone fm) physoporella pauciforata var. variabilis zanin buri 1965 1965a physoporella pauciforata v a r . v a r i a b i l i s n. var.zanin buri, pl. 49, fig. 3 & 6.b.valle dei grassi lunghi, w pasturo, valsassina, e lago di como, lombardia (italie): anisien inférieur (fm dei calcari de recoaro, niveau à dadocrinus gracilis ).holotype: pl. 49, fig. 3, lame mince n° gl 3a, coll. n° 1571, collection c. zanin buri, laboratorio di micropaleontologia, istituto di paleontologia, università di milano (italie) 1988 physoporella .sartorio & venturini, p. 53 bas pars, extrait de zanin buri (1965a: pl. 49, fig. 3) physoporella praealpina pia 1920 1920 physoporella praealpina n. sp.pia, pl. iii, fig. 1-9.horboden, diemtigtal, bern (suisse): anisien. types: pl. iii, fig. 1-3 & 6-7, lame mince n° clvii/3; pl. iii, fig. 4 & 8-9, lame mince n° clvii/2; pl. iii, fig. 5, lame mince n° ?, collection j. von pia, naturhistorisches museum, wien (autriche) 1935a (nom. nud.) (?) oligoporella pilosa forma typica n. forma.pia, fig. 12.sw studenkoviêi, trebeviê, sarajevo (bosnie-herzégovine): anisien 1935a p h y s o p o r e l l a aff. p r a e a l p i n a .pia, fig. 37-39.nw ograda, areæin brijeg grab, bosansko grahovo (bosnie-herzégovine): anisien 135granier & grgasoviê: les algues dasycladales du permien et du trias... 1958 physoporella praealpina .ellenberger, pl. 6, fig. 12-17; pl. 22, fig. 2.roc de la pêche, vanoise, savoie (france): “virglorien” (anisien) 1960 diplopora annulata f o r m a physoporelloidea n. forma.pastwa-leszczyńska & śl i w iński, fig. 6; pl. iv, fig. 15 [= fig. 6].z° e l i sl⁄ awice, nw siewierz, w zawiercie, haute silésie (pologne): anisien (d’après k o t ański, 1979: anisien, illyrien).type (?): fig. 6 = pl. iv, fig. 15, katedrze zlóz̊ rud na agh w krakowie, kraków (pologne) 1961 p h y s o p o r e l l a p r a e a l p i n a .botteron, fig. 6; pl. vi, fig. 1-3 & 4 pars.mont d’or, vaud (suisse): “virglorien” (anisien) supérieur 1963 (?) p h y s o p o r e l l a .herak, fig. 32, à gauche.sv. rok, lika (croatie): anisien, ou d’après herak (1965), greda, golubiê, n knin (croatie): anisien 1964 (?) physoporella dissita .bystrický, pl. xxi, fig. 9.slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur 1964 p h y s o p o r e l l a cf. p r a e a l p i n a .bystrický, pl. xix, fig. 2.szárosz-szoba, silická planina, slovenský k r a s (slovaquie): anisien, pelsonien-illyrien inférieur; pl. xix, fig. 3 & 6.skalny vrch / köveshegy, hucíne, planina koniart, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur; pl. xix, fig. 4.zakázané, silická planina, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur; pl. xix, fig. 7 & 9.roækov, e pleπivec, silická planina, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur; pl. xix, fig. 8.pleπivecká planina, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur; pl. xx, fig. 1-2.gemerská hôrka, w pleπivec, planina koniart, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur 1964 (?) ? p h y s o p o r e l l a cf. p r a e a l p i n a .bystrický, pl. xx, fig. 3.skalny vrch / köveshegy, hucíne, planina koniart, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur 1964 (?) physoporella cf. praealpina .bystrický, pl. xix, fig. 1.zakázané, silická planina, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur; pl. xix, fig. 5.pleπivecká planina, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur 1965 p h y s o p o r e l l a p r a e a l p i n a .bystrický & veizer, pl. iii, fig. 1-2, 4 & 6; pl. iv, fig. 1-2 & 5-6.»ervené vrchy, vysoke tatry (slovaquie): anisien 1965 (?) physoporella cf. praealpina .herak, pl. xii, fig. 5, extrait de herak (1963: fig. 32, à gauche) 1966 p h y s o p o r e l l a p r a e a l p i n a .bystrický, pl. vii, fig. 2.a & 3-4.ponická lehôtka poniky oravce postredná môlëa, e banská bystrica (slovaquie): anisien 1966 (?) physoporella cf. p r a e a l p i n a .hirsch, pl. (p. 85), fig. 5.flexenpaß, vorarlberg (autriche): anisien inférieur-moyen (gutensteiner schichten) 1967a non physoporella praealpina [= oligoporella pilosa var. intusannulata ].herak, pl. 9, fig. 2 1968 p h y s o p o r e l l a p r a e a l p i n a .mégard-galli, fig. 6.i.mte boulliagna, w acceglio, piemonte (italie): anisien moyen 1969 physoporella praealpina .kobel, photo 14-15.masescha, w rätikon (liechtenstein): anisien moyen (gutensteiner schichten) 1969 (?) dasycladaceen physoporella cf. p r a e a l p i n a .kubanek, fig. 15-16.öfenbach, saalfelden, salzburg (autriche): anisien (fassenkalk) 1970 physoporella praealpina .pantiê, pl. v, fig. 4-5.ædrelo, e serbie (yougoslavie): anisien, pelsonien (zone à rhynchonella decurtata ) 1970 p h y s o p o r e l l a aff. p r a e a l p i n a .patrulius, pl. i, fig. 10-11; pl. ii, fig. 1-2.valea lupşa, perşani mts, b ra şov (roumanie): anisien, pelsonien-illyrien inférieur; pl. iv, fig. 6.défilé de l’olt, perşani mts, braşov (roumanie): anisien, pelsonien-illyrien inférieur 1972 non physoporella praealpina [= physoporella pauciforata var. pauciforata ].bleahu et al., pl. iii, fig. 3-4 1972c physoporella praealpina .ott, fig. 1, n° 1-21.martinswand, innsbruck, tirol (autriche): anisien 1973 physoporella praealpina .kotański & »atalov, pl. vi, fig. 1-12; pl. vii, fig. 1-17.staneto, s troyan, loveë (bulgarie): anisien, pelsonien 1973 (nom. nud.) physoporella praealpina var. sulcata n. var.kotański & »atalov, pl. vii, fig. 18-19.staneto, s troyan, loveë (bulgarie): anisien, pelsonien.type non désigné: pl. vii, fig. 18-19, lame mince n° ?, collection z. kotański, panstwowy instytut geologizcny, warszawa (pologne) 1975 (?) physoporella cf. p r a e a l p i n a .baltres, pl. i, fig. 4-8.lacul roşu, e carpathes (roumanie): anisien supérieur 136 geologia croatica 53/1 1975 physoporella praealpina .dragastan & grǎdinaru, pl. iv, fig. 21-23.s dunavát, tulcea (roumanie): anisien, pelsonien-illyrien inférieur 1975 oligoporella pilosa var. intusannulata .pantiê-prodanoviê, pl. xxvi, fig. 1 pars.lapëiêi, budva, monténégro (yougoslavie): anisien 1975 physoporella praealpina .pantiê-prodanoviê, pl. xxvi, fig. 1 pars; pl. xxvii, fig. 1.lapëiêi, budva, monténégro (yougoslavie): anisien 1975 physoporelles.pantiê-prodanoviê, pl. xxviii, fig. 1 pars.lapëiêi, budva, monténégro (yougoslavie): anisien 1979 physoporella praealpina .kotański, pl. 79, fig. 1.a-b, 2.a-b, 2.f, 3 & 10.a-c.tatry (pologne): anisien, illyrien; pl. 79, fig. 16, extrait de pastwa-leszczyńska & śliwiński (1960: pl. iv, fig. 15 = fig. 6) 1980 physoporella praealpina .dragastan, pl. iii, fig. 4.valea saratii, perşani mts, bra şov (roumanie): anisien moyen 1982 physoporella praealpina .bystrický, pl. 3, fig. 2.slatinka nad bebravou ©ípkov, stráæovské vrchy, e trencín (slovaquie): anisien (steinalmkalk) 1986 (?) physoporella cf. p r a e a l p i n a .bystrický, pl. ii, fig. 4.planina koniart, slovenský kras (slovaquie): anisien, bithynien-illyrien inférieur (physoporella pauciforata oligoporella pilosa assemblage zone) 1986 physoporella praealpina .kotański, pl. ciii, fig. 1.a-b, 2.a-b, 2.f, 3 & 10.a-c, extrait de kotański (1979: pl. 79, fig. 1.a-b, 2.a-b, 2.f, 3 & 10.a-c); pl. ciii, fig. 16, extrait de pastwa-leszczyńska & śl i w ińs k i (1960: pl. iv, fig. 15 = fig. 6); pl. cv, fig. 14-15; pl. cvi, fig. 3.forage z ° arki letnisko 11-z, w z ° arki letnisko, ene kozieglowy, haute silésie (pologne): anisien, illyrien; pl. cv, fig. 16; pl. cvi, fig. 1-2, 5, 7 & 8.a-b.forage winowno 25 ww, winowno, siewierz kozieglowy, haute silésie (pologne): anisien, pelsonien; pl. cvi, fig. 4 & 9.a.forage krusin 23 ww, krusin, siewierz kozieglowy, haute silésie (pologne): anisien, pelsonien 1987 physoporella praealpina .strutinski et al., pl. ii, fig. 1.sasca montana, caraş-severin (roumanie): anisien, pelsonien-illyrien inférieur 1994 (?) physoporella aff. p r a e a l p i n a .bucur et al., pl. 10, fig. 1 pars & 5 pars; pl. 11, fig. 10 & 12-15.sasca zone, caraş-severin (roumanie): anisien, pelsonien-illyrien inférieur (sasca fm, valea susara limestone member) physoporella praealpina var. sulcata kotań ski et »atalov 1973, nom. nud. [variété superflue ] physoporella ? rotunda endo 1969, nom. nud. 1969 (nom. nud.) physoporella ? rotunda n. sp.endo, pl. xxvi, fig. 1-5.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancel l i n a).type non désigné: pl. xxvi, fig. 1-5, lames minces n° gk.d 13903, 13213, 13904, 13145 & 13121, kyūshū university, fukuoka (japon) physoporella tenuiaxis endo 1959, nom. nud. 1 9 5 9 (nom. nud.) physoporella tenuiaxis n. sp.endo, pl. 36, fig. 8.sotedani valley, nyūgawa-mura, o _ n o g u n , gifu-ken, honshū (japon): permien moyen (o _ zu fm, zone à neoschwagerina / partie inférieure); pl. 37, fig. 3-4.otani, horadani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien inférieur (o _ zu fm, zone à pseudofusulina).“holotype” (syntypes): pl. 36, fig. 8, lame mince n° 21130; pl. 37, fig. 4, lame mince n° 21048, geol. min. inst., tokyo kyoiku daigaku [tokyo university of educa tion ] (japon) physoporella varicans pia 1935 1935a physoporella varicans n. sp.pia, fig. 43-44.nw blizanac, trebeviê, s sarajevo (bosnie-herzégovine): anisien, pelsonien.types: fig. 43, lame mince n° 551/12; fig. 44, lame mince n° 551/5, collection j. von pia, naturhistorisches museum, wien (autriche) 1935a (?) physoporella ? v a r i c a n s .pia, fig. 45.nw ograda, areæin brijeg grab, bosansko grahovo (bosnieherzégovine): anisien 1957 physoporella varicans .bystrický, pl. vi, fig. 5.n silická planina, slovenský kras (slovaquie): anisien, pelsonien 137granier & grgasoviê: les algues dasycladales du permien et du trias... 1958 physoporella varicans .herak, pl. 13, fig. 6.rastovaëa, graëac, velebit mt (croatie): anisien 1958 ? physoporella varicans .herak, pl. 13, fig. 7.rastovaëa, graëac, velebit mt (croatie): anisien 1964 physoporella varicans .bystrický, pl. xviii, fig. 1, extrait de bystrický (1957: pl. vi, fig. 5); pl. xviii, fig. 2-3.e brzotín, ne pleπivec, slovenský kras (slovaquie): anisien, pelsonien; pl. xviii, fig. 4.?; pl. xviii, fig. 5.szárosz-szoba, silická planina, slovenský kras (slovaquie): anisien, pelsonien; pl. xviii, fig. 6.©títnik, n pleπivec, slovenský kras (slovaquie): anisien, pelsonien 1965 physoporella varicans .assereto et al., pl. 81, fig. 4-5.w castelfranco, val gola / val camónica, ne bergamo, lombardia (italie): anisien (calcare di camorelli) 1965 physoporella varicans .herak, pl. xii, fig. 1.rastovaëa, graëac, velebit mt (croatie): anisien; pl. xii, fig. 2; pl. xiii, fig. 1-2 & 4.plavno pleπivica, nw knin (croatie): anisien 1969 (?) physoporella varicans .diaconu & dragastan, pl. iv, fig. 6.dealul glimeia, apuseni mts (roumanie): anisien supérieur 1970 non physoporella varicans [= oligoporella pilosa var. pilosa].pantiê, pl. ix, fig. 1-4 1972 non physoporella varicans [= ? physoporella pauciforata var. sulcata].bleahu et al., pl. iii, fig. 5 1973 (?) physoporella varicans .popa & dragastan, pl. v, fig. 19 pars.e vǎii iadului, bulz, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à d a d o c r i n u s communis); pl. v, fig. 20.e vǎii iadului, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à dadocrinus communis); pl. x, fig. 39 pars.w lorǎu, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à d a d o c r i n u s communis) 1974 “dasycladaceous limestones”.mello, pl. i, fig. 3 pars.s roæňava, slovenský kras (slovaquie): anisien, pelsonien-illyrien (steinalmkalk) 1978 physoporella varicans .anelkoviê, pl. lxv, fig. 1, extrait de herak (1965: pl. xiii, fig. 2) 1988 physoporella varicans .masaryk, pl. 1, fig. 1.sucha dolina, plavecké podhradie, malé karpaty (slovaquie): anisien, pelsonien 1994 (?) physoporella sp. cf. physoporella varicans .bucur et al., pl. 13, fig. 3.sasca zone, caraşs e v e r i n (roumanie): anisien, pelsonien-illyrien inférieur (sasca fm, valea susara limestone member) physoporella zamparelliae parente et climaco 1999 1997 andrusoporella duplicata .climaco et al., pl. 16, fig. 12 & 13 pars.mte rotonda, e maratea, basilicata (italie): norien 1999 physoporella zamparelliae n. sp.parente & climaco, pl. 37, fig. 1-10; pl. 38, fig. 6 & 9-10; pl. 39, fig. 1.mte rotonda, e maratea, basilicata (italie): norien.holotype: pl. 37, fig. 5, lame mince n° ac554.15; isotypes: pl. 37, fig. 1-4 & 6-7; pl. 38, fig. 9; pl. 39, fig. 1, lame mince n° ac554.15; pl. 37, fig. 8, lame mince n° ac554.10; pl. 37, fig. 9, lame mince n° ac561.1; pl. 37, fig. 10, lame mince n° ac554a; pl. 38, fig. 6, lame mince n° ac561.8; pl. 38, fig. 10, lame mince n° ac561.9, collection v. zamparelli, dipartimento di scienze della terra, università di napoli “federico ii” (italie) pianella radoi»i∆ 1962, nom. nud. pianella jomdaensis mu 1982, nom. nud. 1 9 8 2 (nom. nud.) pianella jomdaensis n. sp.mu, pl. ix, fig. 11-12.xizang / tibet (chine populaire): trias supérieur.holotype: pl. ix, fig. 11, lame mince n° pb8077, nanjing institute of geology and pale ontology, academia sinica, nanjing (chine populaire) placklesia bilgütay 1968 *placklesia multipora bilgütay 1968 1968 placklesia multipora n. gen. n. sp.bilgütay, fig. 4.a-b; pl. iii, fig. 1-9.plackles, hohe wand, niederösterreich (autriche): rhétien.holotype: pl. iii, fig. 8, lame mince n° 0321; paratypes: lames minces n° 0322-0329, geologische bundesantalt, wien (autriche) 138 geologia croatica 53/1 1968 (?) physoporella minutula. bilgütay, pl. iii, fig. 10.plackles, hohe wand, niederösterreich (autriche): rhétien 1976 placklesia multipora .tollmann, fig. 171.plackles, hohe wand, niederösterreich (autriche): rhétien 1980 placklesia multipora .senowbari-daryan, pl. 12, fig. 5-6.feichtenstein, hintersee, salzburg (autriche): rhétien (kössener schichten) 1993 placklesia multipora .senowbari-daryan & e. flügel, pl. 11, fig. 3-4.feichtenstein, hintersee, salzburg (autriche): rhétien (kössener schichten) poikiloporella pia 1943 poikiloporella affinis endo 1969, non 1968 1968b (nom. nud.) poikiloporella affinis n. sp.endo, “chart”, non figurée.type non figuré 1969 poikiloporella affinis n. sp.endo, pl. xxiii, fig. 5-8.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à neoschwageri na simplex / partie inférieure).holotype: pl. xxiii, fig. 5, lame mince n° gk.d 13502, ky ūshū university, fukuoka (japon) poikiloporella brezovica (bystrický 1967) kollárová-andrusovová et bystrický 1974 [= andrusoporella brezovica bystrický 1967] 1967b andrusoporella brezovica n. sp.bystrický, pl. v, fig. 1-4 & 6-7; pl. vi, fig. 1-6; pl. vii, fig. 3-4.w silická brezová, slovenský kras (slovaquie): carnien (wettersteinkalk), julien; pl. v, fig. 5.w silická brezová, slovenský kras (slovaquie): carnien, ou d’après bystrický (1986): carnien, julien (a n d r u s o porella duplicata taxon-range zone).holotype: pl. v, fig. 1, lame mince n° 2157, collection j. bystrický , geological institute, slovak academy of sciences, bratislava (slovaquie) 1974 poikiloporella brezovica n. comb.kollárová-andrusovová & bystrický, p. 129, non figurée 1986 andrusoporella brezovica .bystrický, pl. v, fig. 3, extrait de bystrický (1967b: pl. v, fig. 5) poikiloporella bystrickyi (endo 1969) emberger 1976 [= andrusoporella bystrickyi endo 1969] 1969 andrusoporella bystrickyi n. sp.endo, pl. xxxvi, fig. 4-8; pl. xxxvii, fig. 1-2.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à c a n c e l l i n a ).holotype: pl. xxxvii, fig. 1, lame mince n° gk.d 13049, kyū s hū u n iversity, fukuoka (japon) 1976 poikiloporella bystricky n. comb. [sic].emberger, p. 18 & 68, non figurée *poikiloporella duplicata (pia 1920) 1943 [= oligoporella duplicata pia 1920 ] 1920 oligoporella duplicata n. sp.pia, pl. ii, fig. 23-29.potzenreiteralm, sw weyer, oberösterreich (autriche): trias (en éboulis).types: pl. ii, fig. 23-29, collection j. von pia, naturhistorisches museum, wien (autriche) 1940c (?) g y r o p o r e l l a aff. a m p l e f o r a t a .pia, pl. 6, fig. 14-16.n alberfeldkogel, höllengebirge, oberösterreich (autriche): ladinien (wettersteinkalk) 1943 poikiloporella duplicata n. gen. n. comb.pia, p. 95, non figurée 1948 gyroporella verticillata n. sp.kamptner in trauth, pl. xi, fig. 1-3.lunzbergstollen, n lunz, niederösterreich (autriche): trias supérieur.types: pl. xi, fig. 1-3, échantillon n° 504, collection e. kamptner, naturhistorisches museum, wien (autriche) 1957 oligoporella duplicata .bystrický, pl. v, fig. 6.n silická planina, slovenský kras (slovaquie): ladinien terminal; pl. v, fig. 7.kardos, s pleπivecká planina, slovenský kras (slovaquie): ladinien terminal 1961 oligoporella duplicata .johnson, pl. 54, fig. 3-4, extrait de pia (1920: pl. ii, fig. 28-29); pl. 54, fig. 5, extrait de pia (1920: pl. ii, fig. 26) 139granier & grgasoviê: les algues dasycladales du permien et du trias... 1962 andrusoporella fusani n. gen. n. sp.bystrický, pl. iii, fig. 5-8; pl. iv, fig. 1.n budikovaný, w pleπivec (slovaquie): ladinien (wettersteinkalk).holotype: pl. iii (non v), fig. 5, lame mince n° v-3428/m, collection j. bystricky´, geologický ústav dioný za ©túra, bratislava (slovaquie) 1962 gyroporella ladinica n. sp.bystrický, pl. iii, fig. 4.n beres tetö, háj, turnianske podhradie / turna nad bodvou, slovenský kras (slovaquie): ladinien supérieur (wettersteinkalk).holotype: pl. iii, fig. 4, lame mince n° 1025, collection j. bystricky ´, geologický ústav dioný za ©túra, bratislava (slovaquie) 1963 poikiloporella duplicata .ott, fig. 30-43.zahmer kaiser et/ou karwendelgebirge, tirol (autriche): ladinien supérieur (oberer wettersteinkalk) 1964 andrusoporella fusani.bystrický, pl. vii, fig. 7.mlynský vrch, silická brezová, slovenský kras (slovaquie): ladinien ? carnien; pl. vii, fig. 8-9; pl. viii, fig. 1 & 6.budikovaný, w pleπivec (slovaquie): ladinien; pl. viii, fig. 2, extrait de bystrický (1962: pl. iii, fig. 5); pl. viii, fig. 3, extrait de bystrický (1962: pl. iii, fig. 7); pl. viii, fig. 4, extrait de bystrický (1962: pl. iii, fig. 6); pl. viii, fig. 5.nw slavec, ne pleπivec, slovenský kras (slovaquie): ladinien; pl. viii, fig. 7, extrait de bystrický (1962: pl. iv, fig. 1); pl. viii, fig. 8, extrait de bystrický (1962: pl. iii, fig. 8) 1964 (?) ? g r i p h o p o r e l l a sp.bystrický, pl. vii, fig. 5.nw slavec, ne pleπivec, slovenský kras (slovaquie): ladinien 1964 g y r o p o r e l l a cf. a m p l e f o r a t a .bystrický, pl. vii, fig. 3.e brzotín, ne pleπivec, slovenský kras (slovaquie): ladinien supérieur; pl. vii, fig. 4.? 1964 gyroporella ladinica .bystrický, pl. vii, fig. 1, extrait de bystrický (1962: pl. iii, fig. 4); pl. vii, fig. 2.e brzotín, ne pleπivec, slovenský kras (slovaquie): ladinien supérieur 1964 poikiloporella duplicata .bystrický, pl. ix, fig. 1.kardos, s pleπivecká planina, slovenský kras (slovaquie): ladinien; pl. ix, fig. 2.mlynský vrch, silická brezová, slovenský kras (slovaquie): ? ladinien-carnien; pl. ix, fig. 3.budikovaný, w pleπivec (slovaquie): ? ladinien-carnien 1965 poikiloporella duplicata .dondi & papetti, pl. v, fig. 1-4; pl. vi, fig. 1-7.forage contursi 1, s bivio palomonte, campania (italie): trias 1965a andrusoporella longobardica n. sp.zanin buri, pl. 51, fig. 4-8; pl. 52, fig. 2.a-b; pl. 53, fig. 1-2, 3 [= pl. 51, fig. 5] & 4-5.borno, val camónica, ne bergamo, lombardia (italie): ladinien supérieur ? carnien inférieur.holotype: pl. 51, fig. 5 = pl. 53, fig. 3, lame mince n° vc 1, coll. n° 1570, collec tion commizzoli del servizio geologico italiano, laboratorio di micropaleontologia, istituto di paleontologia, università di milano (italie) 1967b andrusoporella fusani .bystrický, pl. vii, fig. 1-2 & 5; pl. viii, fig. 1.ostré vrπky, pleπivecká planina, s l o v e n s ký kras (slovaquie): carnien, julien; pl. vii, fig. 6; pl. viii, fig. 2-3 & 5-6.w tisovec, muráňska planina (slovaquie): carnien, julien supérieur tuvalien; pl. viii, fig. 4.w silická brezová, slovenský kras (slovaquie): carnien, julien 1967 poikiloporella duplicata .holzer, pl. 1, fig. 3.budikovaný, w pleπivec (slovaquie): ladinien; pl. 1, fig. 4-6.s klaus an der pyhrnbahn, steyrtal, oberösterreich (autriche): carnien, cordevolien (wettersteinkalk); pl. 1, fig. 7.almtal, oberösterreich (autriche): ladinien supérieur (wettersteinkalk) 1968 poikiloporella duplicata .toschek, fig. 5.kaisergebirge, tirol (autriche): ladinien (wettersteinkalk) 1969 g y r o p o r e l l a cf. a m p l e f o r a t a .diaconu & dragastan, pl. iv, fig. 1-2.valea crişului repede, apuseni mts, bihor (roumanie): ladinien 1970 andrusoporella fusani.patrulius, pl. iii, fig. 3-5; pl. iv, fig. 5; pl. v, fig. 4.défilé de l’olt, perşani mts, braşov (roumanie): carnien 1972 poikiloporella duplicata .miπík, pl. xxxvii, fig. 1; pl. xxxviii, fig. 1.svit, nízke tatry (slovaquie): norien (hauptdolomit) 1972 dasycladaceen.miπík, pl. xxxvii, fig. 2.svit, nízke tatry (slovaquie): norien (hauptdolomit) 1972 poikiloporella duplicata .pantiê & rampnoux, pl. ii, fig. 5-6.popov do, ljubiπnja mt, monténégro (yougoslavie): carnien 1972b poikiloporella duplicata .zorn, fig. 3.5-6.n ettaler mandl, oberammergau, bayern (allemagne): trias ? moyen (oberer wettersteinkalk) 1973 (?) poikiloporella duplicata .wolff, pl. 7, fig. 5.wendelstein kampenwand, bayern (allemagne): ladinien 1974 poikiloporella duplicata .pantiê, pl. v, fig. 3.ruisseau ljubeniê, prokletije mts, kosovo, serbie (yougoslavie): carnien 140 geologia croatica 53/1 1975 poikiloporella duplicata .pantiê-prodanoviê, pl. lxxiii, fig. 1-2.mileπev do, e prijepolje, serbie (yougoslavie): carnien 1976 poikiloporella duplicata .hanáëek, pl. vii, fig. 1; pl. viii, fig. 4; pl. ix, fig. 3 pars.stráæovské vrchy, e trencín (slovaquie): carnien, cordevolien (wettersteinkalk) 1976 poikiloporella duplicata .tollmann, fig. 79.schönhaltereck, mürz, steiermark (autriche): carnien (tisoveckalk) 1977 poikiloporella duplicata .miπík, mock & sýkora, pl. iii, fig. 4.podbiel, w carpathes (slovaquie): carnien (galet de tisoveckalk dans un conglomérat crétacé) 1979 andrusoporella duplicata n. comb.bystrický, pl. iii, fig. 1 & 3.colline kopa, n stratená, n dobπiná, stratenská hornatina mts (slovaquie): carnien supérieur (tisoveckalk); pl. iii, fig. 2.vyπná záhrada, stratenská hornatina mts (slovaquie): carnien supérieur (tisoveckalk) 1980 poikiloporella duplicata .dragastan, pl. vii, fig. 13, extrait de diaconu & dragastan (1969: pl. iv, fig. 2); pl. vii, fig. 14, extrait de diaconu & dragastan (1969: pl. iv, fig. 1) 1980a poikiloporella duplicata .dullo, pl. 1, fig. 1.1.d’après dullo & lein (1982): kreuzkogel, se admont, gesäuse, steiermark (autriche): carnien (leckkogelschichten); pl. 1, fig. 3; pl. 2, fig. 1.sw gesäuse, steiermark (autriche): carnien (tisoveckalk) 1980b poikiloporella duplicata .dullo, pl. 10, fig. 8.kreuzkogel, se admont, gesäuse, steiermark (autriche): carnien (tisoveckalk) 1982 andrusoporella duplicata .bystrický, pl. 3, fig. 3-4.slatinka nad bebravou ©ípkov, stráæovské vrchy, e trencín (slovaquie): carnien (wettersteinkalk) 1982 poikiloporella duplicata .dullo & lein, pl. 4, fig. 5 pars, extrait de dullo (1980a: pl. 1, fig. 1) 1982 poikiloporella duplicata .henrich, pl. 13, fig. 7.1.scharnkopf, hochstaufen-zwieselmassif, w salzburg, bayern (allemagne): carnien, cordevolien (wettersteinkalk) 1982 poikiloporella duplicata .schäfer & senowbari-daryan, pl. 19, fig. 3 pars.didymi mts, argolís (grèce): carnien (pantokrator limestones) 1983 poikiloporella duplicata .schäfer & senowbari-daryan, pl. 6, fig. 3-4.didymi mts, argolís (grèce): carnien 1984 poikiloporella duplicata .henrich, pl. 9, fig. 6.1.extrait de henrich (1982: pl. 13, fig. 7.1); pl. 15, fig. 1.1.rauschberg, hochstaufen zwieselmassif, w salzburg, bayern (allemagne): carnien, cordevolien (wettersteinkalk) 1984 poikiloporella duplicata .ogorelec et al., pl. 9, fig. 3 pars & 4 pars.izvir nadize, tamar, w vrπië, w kranjska gora (slovénie): carnien, julien-tuvalien 1986 andrusoporella duplicata .bystrický, pl. v, fig. 1.budikovaný, w pleπivec (slovaquie): carnien; pl. v, fig. 2.s vëeláre, dolný vrch, slovenský kras (slovaquie): carnien (andrusoporella duplicata t a x o n range zone) 1986 poikiloporella duplicata .sudar, pl. xxvii, fig. 2.sokolarica ©ljivovica tarabiêa brdo, tara mt, w serbie (yougoslavie): carnien, cordevolien (wettersteinkalk); pl. xxvii, fig. 3.sokolarica ©ljivovica tarabiêa brdo, tara mt, w serbie (yougoslavie): carnien, julien-tuvalien (dachsteinkalk) 1988 poikiloporella duplicata .hagemeister, pl. 9, fig. 1.drauzug, kärnten (autriche): carnien (raibler schichten) 1988 andrusoporella fusani .pfeiffer, pl. 11, fig. 2.gartnerkofel, s hermagor, kärnten (autriche): ladinien, fassanien (schlerndolomit) 1988 poikiloporella duplicata .sartorio & venturini, p. 56, haut.forage contursi 1, s bivio palomonte, campania (italie): carnien 1988 poikiloporella duplicata .vachard & fontaine, pl. ii, fig. 1.affluent du sungai sinyum, peninsular malaysia (malaisie): ladinien-carnien 1988 poikiloporella duplicata .vachard in fontaine, khoo & vachard, fig. 6.o.gunung sinyum, sungai sinyum, peninsular malaysia (malaisie): ladinien-carnien 1989 andrusoporella duplicata .buëek, pl. iii, fig. 6.plavecký mikuláπ, malé karpaty (slovaquie): carnien, cordevolien (tisoveckalk) 1993 poikiloporella duplicata .ogorelec & rothe, pl. 1, fig. 2.trnovski gozd, idrija nova gorica, w ljubljana (slovénie): carnien 1997 non andrusoporella duplicata [=physoporella zamparelliae ].climaco et al., pl. 16, fig. 12 & 13 pars 141granier & grgasoviê: les algues dasycladales du permien et du trias... poikiloporella humilis (endo 1969) emberger 1976, nom. nud. [= andrusoporella ? humilis endo 1969, nom. nud. ] 1969 (nom. nud.) andrusoporella (?) humilis n. sp.endo, pl. xxxv, fig. 7-8; pl. xxxvi, fig. 3; pl. xxxvii, fig. 11.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à c a n c e l l i n a ).type non désigné: pl. xxxv, fig. 8; pl. xxxvii, fig. 11, lame mince n° gk.d 13325; pl. xxxv, fig. 7, lame mince n° gk.d 13055; pl. xxxvi, fig. 3, lame mince n° gk.d 13146, kyūshū university, fukuoka (japon) 1976 (nom. nud.) poikiloporella humilis n. comb.emberger, p. 18 & 69, non figurée poikiloporella grandiramosa endo 1969 1969 poikiloporella grandiramosa n. sp.endo, pl. xx, fig. 8-10; pl. xxi, fig. 1.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à c a n c e l l i n a ).holotype: pl. xx, fig. 8, lame mince n° gk.d 13255, kyū s hū u n i v e r s i t y , fukuoka (japon) poikiloporella japonica ishijima et al. 1971 1971 poikiloporella japonica n. sp.ishijima et al., pl. 11, fig. 12; pl. 12, fig. 4.sakaishimachibun, aganomura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur”.holotype: pl. 11, fig. 12, spécimen n° nsmp1-18120a, national science museum, tokyo (japon) 1981 poikiloporella japonica .nakamura, pl. 7, fig. 8; pl. 10, fig. 1.ishiyama, o _ n o c hō tanigumi-mura, gifu-ken, honshū (japon): permien (ishiyama limestone) poikiloporella thaiensis endo 1968, nom. nud. 1968b (nom. nud.) poikiloporella thaiensis n. sp.endo, pl. ii, fig. 3-4.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien.type non désigné: pl. ii, fig. 3, lame mince n° 13499; pl. ii, fig. 4, lame mince n° 13488, departement of geology, ky ūshū university, fukuo ka (japon) 1969 (nom. nud.) poikiloporella thaiensis .endo, pl. xxi, fig. 2-9; pl. xxii, fig. 1-7.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina zone à neoschwagerina simplex / partie inférieure) poncetella güvenç 1979, non mamet et roux 1983 poncetella helvetica (pia 1912) güvenç 1979 [= macroporella ? helvetica pia 1912; = diplopora helvetica (pia 1912) 1920] 1912 macroporella ? helvetica n. sp.pia, pl. ii(i), fig. 16-17.mythen, zweckenalp, schwyz (suisse): trias ? moyen (wettersteinkalk).types: pl. ii(i), fig. 16, lame mince n° xvi/3; pl. ii(i), fig. 17, lame mince n° xvi/1, collection j. von pia, naturhistorisches museum, wien (autriche) 1920 diplopora helvetica n. comb.pia, pl. iii, fig. 16.mythen, zweckenalp, schwyz (suisse): trias moyen, ? anisien (wettersteinkalk) 1964 diplopora helvetica .bystrický, pl. xxiii, fig. 5 & 7.kamenec, s dlhá ves, se pleπivec, slovenský kras (slovaquie): anisien, illyrien inférieur; pl. xxiii, fig. 6.silická brezová, slovenský kras (slovaquie): anisien, pelsonien 1965 diplopora hexaster subsp. h e l v e t i c a n. subsp.herak, pl. viii, fig. 1-2.zlatibor mt, w serbie (yougoslavie): anisien 1966 diplopora helvetica .bystrický, pl. viii, fig. 3.ponická lehôtka poniky oravce postredná môlëa, e banská bystrica (slovaquie): anisien, pelsonien (steinalmkalk) 1967b diplopora hexaster subsp. h e l v e t i c a.herak, pl. 3, fig. 1.loßeck, gosaukamm, dachsteingruppe, oberösterreich (autriche): anisien (massenkalk) 1967 diplopora helvetica .hurka, pl. 7, fig. 6.e bagni di piandimáia / bad maistatt, villabassa / niederdorf, pusteria / pustertal, trentino alto adige (italie): anisien (pragser dolomiten), hydaspien 1969 diplopora helvetica .kobel, photo 13.vorder valorsch, w rätikon (liechtenstein): anisien moyen (gutensteiner schichten) 142 geologia croatica 53/1 1969 m a c r o p o r e l l a a l p i n a .kobel, photo 12.vorder valorsch, w rätikon (liechtenstein): anisien moyen (gutensteiner schichten) 1970 diplopora helvetica .patrulius, pl. i, fig. 1-4.valea nadaş, racoşul de sus, perşani mts, braşo v (roumanie): anisien, pelsonien 1975 diplopora helvetica .baltres, pl. ii, fig. 2-3.lacul roşu, e carpathes (roumanie): anisien supérieur 1979 poncetella helvetica n. comb.güvenç, p. 632, non figurée 1987 diplopora helvetica .strutinski, bucur, nicu, pop-stratila & török, pl. ii, fig. 6.sasca montana, caraşseverin (roumanie): anisien, pelsonien-illyrien inférieur 1989 diplopora hexaster v a r . h e l v e t i c a.buëek, pl. ii, fig. 4.n havranica, malé karpaty (slovaquie): anisien, pelsonien-illyrien inférieur (steinalmkalk) 1995 (?) d i p l o p o r a .pantiê-prodanoviê, pl. i, fig. 11.beπiêi, noriêi, w srebrenica (bosnie-herzégovine): anisien *poncetella hexaster (pia 1912) güvenç 1979 [= kantia hexaster pia 1912; = diplopora hexaster (pia 1912) 1920 ] 1912 kantia hexaster n. sp.pia, pl. vi(v), fig. 13.w lapëiêi, budva, monténégro (yougoslavie): trias moyen.type: pl. vi(v), fig. 13, lame mince n° i/3, collection j. von pia, naturhistorisches muse um, wien (autriche) 1920 diplopora hexaster n. comb.pia, pl. iii, fig. 26-32.sw studenkoviêi, trebeviê, sarajevo (bosnieherzégovine): anisien fig. 22 diplopora hexaster subsp. helvetica (herak, 1965, pl. viii, fig. 2), x17. fig. 23 diplopora hexaster subsp. hexaster (herak, 1965, pl. viii, fig. 4), x17. 143granier & grgasoviê: les algues dasycladales du permien et du trias... 1921 (?) k a n t i a cf. h e x a s t e r .bubnoff, pl. x, fig. 11-12.forno, n predrazzo, val di fiemme, trentino alto adige (italie): ladinien 1935a diplopora hexaster .pia, pl. iv, fig. 1 & 3.w trebeviê, s sarajevo (bosnie-herzégovine): anisien, hydaspien supérieur pelsonien; pl. iv, fig. 2, extrait de pia (1920: pl. iii, fig. 32) 1940b diplopora hexaster .pia, pl., fig. 10.silická brezová, slovenský kras (slovaquie): anisien, pelsonien 1957 diplopora hexaster .bystrický, pl. vii, fig. 1-2.skalica, w gemerská hôrka, w pleπivec, planina koniart, slovenský kras (slovaquie): anisien, pelsonien, ou d’après bystrický (1986): anisien, pelsonien-illyrien inférieur (physoporella pauciforata oligoporella pilosa assemblage zone); pl. vii, fig. 2.skalica, w gemerská hôrka, w pleπivec, planina koniart, slovenský kras (slovaquie): anisien, pelsonien 1964 diplopora hexaster .bystrický, pl. xxii, fig. 1.zakázané, silická planina, slovenský kras (slovaquie): anisien, pelsonien; pl. xxii, fig. 2, extrait de bystrický (1957: pl. vii, fig. 1); pl. xxii, fig. 3-4; pl. xxiii, fig. 3-4.roækov, e pleπivec, silická planina, slovenský kras (slovaquie): anisien, pelsonien; pl. xxii, fig. 5-6 & 8.silická brezová, slovenský kras (slovaquie): anisien, pelsonien; pl. xxii, fig. 7.s l o v e n s ký kras (slovaquie): anisien, pelsonien; pl. xxiii, fig. 1-2.pleπivecká planina, slovenský k r a s (slovaquie): anisien, pelsonien-illyrien 1965 diplopora hexaster .bystrický & veizer, pl. iv, fig. 4.»ervené vrchy, vysoke tatry (slovaquie): anisien 1965 diplopora hexaster subsp. h e x a s t e r n. subsp.herak, pl. viii, fig. 3-4.zlatibor mt, w serbie (yougoslavie): anisien 1967 diplopora hexaster .hurka, pl. 7, fig. 3.e bagni di piandimáia / bad maistatt, villabassa / niederdorf, pusteria / pustertal, trentino alto adige (italie): anisien (pragser dolomiten), hydaspien 1967 diplopora hexaster .pantiê, pl. ii, fig. 6-7.pepeljevaëke stene, tara mt, w serbie (yougoslavie): anisien 1969 diplopora hexaster .diaconu & dragastan, pl. viii, fig. 1-3.dealul glimeia, apuseni mts (roumanie): ladinien 1970 diplopora hexaster .pantiê, pl. vi, fig. 1-3 & 4.a.ædrelo, e serbie (yougoslavie): anisien, pelsonien (“zone avec rhynchonella decurtata”) 1970 diplopora hexaster .papp & turnovsky, pl. 10 pars.sw gosaukamm, dachsteingruppe, salzburg (autriche): anisien (massenkalk) 1970 diplopora hexaster .patrulius, pl. i, fig. 5.valea nadaş, racoşul de sus, perşani mts, braşo v (roumanie): anisien, pelsonien 1972 diplopora hexaster .bleahu et al., pl. v, fig. 5.vaşcǎu plateau, apuseni mts, bihor (roumanie): anisien moyen-supérieur 1972c diplopora hexaster .ott, fig. 3, n° 3-5.martinswand, innsbruck, tirol et/ou n grießspitzen, miemingergebirge, tirol (autriche): anisien 1972 diplopora hexaster var. h e x a s t e r .samuel, borza & köhler, pl. cxii, fig. 1-2.nosice-milochov, w carpathes (slovaquie): anisien (galet dans un conglomérat albien) 1973 diplopora hexaster .popa & dragastan, pl. vii, fig. 26 pars; pl. viii, fig. 30 pars; pl. xiii, fig. 49 pars, 50 pars, 51 pars & 52 pars.e lorǎu, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à dadocrinus communis); pl. xiv, fig. 55 pars.e vǎii iadului, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à dadocrinus communis) 1975 diplopora hexaster .baltres, pl. ii, fig. 1.lacul roşu, e carpathes (roumanie): anisien supérieur 1975 diplopora hexaster .dragastan & grǎdinaru, pl. iv, fig. 27.s dunavát, tulcea (roumanie): anisien, pelsonien-illyrien inférieur 1975 diplopora hexaster .pantiê-prodanoviê, pl. xxix, fig. 1 pars.pepeljevaëke stene, tara mt, w serbie (yougoslavie): anisien 1978 diplopora hexaster var. hexaster.anelkoviê, pl. lxv, fig. 8, extrait de herak (1965: pl. viii, fig. 3) 1979 poncetella hexaster n. gen. n. comb.güvenç, p. 631, non figurée 1979 diplopora hexaster .kotański, pl. 79, fig. 13-15.tatry (pologne): anisien, illyrien 1980 diplopora hexaster .dragastan, pl. iii, fig. 2 & 6.valea saratii, perşani mts, braşov (roumanie): anisien moyen; pl. iv, fig. 5, extrait de popa & dragastan (1973: pl. xiii, fig. 49 pars) 144 geologia croatica 53/1 1986 diplopora hexaster var. hexaster.bystrický, pl. iii, fig. 4.silická brezová, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur (physoporella pauciforata oligoporella pilosa assemblage zone); pl. iii, fig. 7, extrait de bystrický (1957: pl. vii, fig. 1) 1986 diplopora hexaster .kotański, pl. ciii, fig. 13-15, extrait de kotański (1979: pl. 79, fig. 13-15) 1986 diplopora hexaster .sudar, pl. xxv, fig. 3.studenkoviêi, trebeviê, sarajevo (bosnie-herzégovine): anisien, pelsonien (dedoviêi carbonates) 1987 (?) diplopora cf. h e x a s t e r .strutinski, bucur, nicu, pop-stratila & török, pl. ii, fig. 5.sasca montana, caraş-severin (roumanie): anisien, pelsonien-illyrien inférieur 1989 diplopora hexaster var. hexaster .buëek, pl. i, fig. 7.n havranica, malé karpaty (slovaquie): anisien, pelsonien-illyrien inférieur (steinalmkalk) 1993 diplopora hexaster .senowbari-daryan et al., pl. 56, fig. 12.valdáora / olang, pusteria / pustertal, trentino alto adige (italie): anisien supérieur 1994 poncetella hexaster .bucur et al., pl. 13, fig. 4-5 & 9-10.sasca zone, caraş-severin (roumanie): anisien, pelsonien-illyrien inférieur (sasca fm, valea susara limestone member) 1994 poncetella hexaster .e. flügel et al., pl. 1, fig. 7-9.bled (slovénie): anisien, ? ‘aegean’ pelsonien pseudoepimastopora endo 1960, nom. nud. pseudoepimastopora ampullacea elliott 1968, nom. nud. [cf. epimastoporella ? ampullacea elliott ex roux 1979 ] pseudoepimastopora ? impera rácz 1966, nom. nud. 1966 (nom. nud.) pseudoepimastopora ? impera n. sp.rácz, pl. iv, fig. 20-22.n cervera de pisuerga, n palencia (espagne): carbonifère, silésien, ouralien (zone à p r o t r i t i c i t e s ).“holotype and paratypes” (type non clairement désigné): pl. iv, fig. 20-22, lames minces n° r.m.g.m. 130017 & 130009, collection l. rácz, geological museum, leiden (pays-bas) 1 9 7 4 (?) (nom. nud.) pseudoepimastopora aff. i m p e r a .chuvashov, pl. xi, fig. 9.w yekaterinburg, w oural (fédération de russie): assélien pseudoepimastopora iwaizakiensis (endo 1953) h. flügel 1963, nom. nud. [cf. epimastoporella iwaizakiensis (endo 1953) roux 1979 ] pseudoepimastopora japonica (endo 1951) 1960, nom. nud. [cf. epimastoporella japonica (endo 1951) roux 1979 ] pseudoepimastopora kroatiaca homann 1972, nom. nud. [“synonyme” de epimastoporella japonica (endo 1951) roux 1979 ] pseudoepimastopora likana (kochansky et herak 1960) h. flügel 1963, nom. nud. [= epimastopora likana kochansky et herak 1960; synonyme postérieur de epimastoporella japonica (endo 1951) roux 1979, d’après mamet et roux in mamet et al. 1987 ] *pseudoepimastopora pertunda endo 1960, nom. nud. 1 9 6 0 (nom. nud.) pseudoepimastopora pertunda n. gen. n. sp.endo, pl. 44, fig. 2-6.kuroiwa-chōjagamori, se kuroiwa, kyowa, shuhōc hō, ne mine-shi, yamaguchi-ken, honshū (japon): permien inférieur (akiyoshi limestone group, zone à p s e u d o s c h w a g e r i n a , sous-zone à triticites simplex).“holotypes” (syntypes): pl. 44, fig. 3, lame mince n° 611; pl. 44, fig. 5, lame mince n° 639, kyū s hū u n i v e r s i t y , fukuoka (japon) 1 9 6 1 c (nom. nud.) pseudoepimastopora pertunda .endo, pl. 6, fig. 7.kuroiwa-chōjagamori, se kuroiwa, kyowa, shuhōc hō, ne mine-shi, yamaguchi-ken, honshū (japon): permien inférieur (akiyoshi limestone group, zone à pseudoschwagerina , sous-zone à triticites simplex) 145granier & grgasoviê: les algues dasycladales du permien et du trias... 1963 (nom. nud.) pseudoepimastopora pertunda .johnson, pl. 69, fig. 2-6, extrait de endo (1960: pl. 44, fig. 2-6) 1 9 7 7 (nom. nud.) pseudoepimastopora pertunda .vachard in h. & g. termier & vachard, pl. 2, fig. 5.djebel tebaga (tunisie): murghabien (calcaires à bellerophon) 1979b (nom. nud.) epimastoporella pertunda n. comb.roux, p. 809, non figurée 1 9 8 2 (?) (nom. nud.) pseudoepimastopora aff. p e r t u n d a .mu, pl. vii, fig. 8.xizang / tibet (chine populaire): carbonifère, silésien pseudoepimastopora shachtauensis kulik 1978, nom. nud. 1 9 7 8 (nom. nud.) pseudoepimastopora shachtauensis n. sp.kulik, pl. vi, fig. 5 & 7.shakhtau massif, bashkirskaya (fédération de russie): assélien, kurmainskien (zone à schwagerina sphaerica et pseudo fusulina firma, zone ass3); pl. vi, fig. 6.shakhtau massif, bashkirskaya (fédération de russie): a s s é l i e n.holotype: pl. vi, fig. 5, lame mince n° 4513/34-4, collection e.l. kulik, geologicheski institut akademije nauk sssr (fédération de russie) pseudogyroporella endo 1959, nom. nud. pseudogyroporella annulata ishijima et al. 1971, nom. nud. 1971 (nom. nud.) pseudogyroporella annulata n. sp.ishijima et al., pl. 5, fig. 4.b; pl. 6, fig. 7-11.sakaishimachibun, agano-mura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur”.holotype: pl. 6, fig. 10, spécimen n° nsmp1-18109b, national science museum, tokyo (japon) pseudogyroporella biporosa endo 1969, nom. nud. 1 9 6 9 (nom. nud.) pseudogyroporella biporosa n. sp.endo, pl. xxxix, fig. 6; pl. xl, fig. 7-8.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à c a n c e l l i n a zone à neochwagerina simplex / partie inférieure).holotype: pl. xxxix, fig. 6, lame mince n° gk.d 13979, kyūshū university, fukuoka (japon) pseudogyroporella elliptica ishijima et al. 1971, nom. nud. 1 9 7 1 (nom. nud.) pseudogyroporella elliptica n. sp.ishijima et al., pl. 5, fig. 5-9.sakaishimachibun, aganomura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur”.holotype: pl. 5, fig. 5, spécimen n° nsmp1-18129a, national science museum, tokyo (japon) pseudogyroporella elongata ishijima et al. 1971, nom. nud. 1971 (nom. nud.) pseudogyroporella elongata n. sp.ishijima et al., pl. 4, fig. 8.a-b.sakaishimachibun, aganomura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur”.holotype: pl. 4, fig. 8.a, spécimen n° nsmp1-18104e, national science museum, tokyo (japon) pseudogyroporella endoi ishijima et al. 1971, nom. nud. 1 9 7 1 (nom. nud.) pseudogyroporella endoi n. sp.ishijima et al., pl. 4, fig. 2-5.sakaishimachibun, agano-mura, h a n nō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur”.holotype: pl. 4, fig. 2, spécimen n° nsmp1-18101a, national science museum, tokyo (japon) pseudogyroporella grandis kordé 1965, nom. nud. 1 9 6 5 (nom. nud.) pseudogyroporella grandis n. sp.kordé, pl. lviii, fig. 5.a-b & 6.dorasham 2, dzhul’fa, nakhichevan’ (azerbaïdjan): guadalupien.“golotip” (syntypes): pl. lviii, fig. 5.a-b, lame mince n° 2307/14, collection k.b. kordé, moscou (fédération de russie) pseudogyroporella longiporosa ishijima et al. 1971, nom. nud. 1971 (nom. nud.) pseudogyroporella longiporosa n. sp.ishijima et al., pl. 4, fig. 6-7.sakaishimachibun, aganomura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur”.holotype: pl. 4, fig. 6, spécimen n° nsmp1-18094b, national science museum, tokyo (japon) 146 geologia croatica 53/1 pseudogyroporella longithalla ishijima et al. 1971, nom. nud. 1 9 7 1 (nom. nud.) pseudogyroporella longithalla n. sp.ishijima et al., pl. 5, fig. 1-2.sakaishimachibun, aganomura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur”.holotype: pl. 5, fig. 1, spécimen n° nsmp1-18119a, national science museum, tokyo (japon) pseudogyroporella macroporosa ishijima et al. 1971, nom. nud. 1 9 7 1 (nom. nud.) pseudogyroporella macroporosa n. sp.ishijima et al., pl. 6, fig. 1-3.sakaishimachibun, agano-mura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur”.holotype: pl. 6, fig. 1, spécimen n° nsmp1-18106a, national science museum, tokyo (japon) pseudogyroporella minor ishijima et al. 1971, nom. nud. 1 9 7 1 (nom. nud.) pseudogyroporella minor n. sp.ishijima et al., pl. 5, fig. 3-4.a.sakaishimachibun, aganomura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur”.holotype: pl. 5, fig. 3, spécimen n° nsmp1-18124, national science museum, tokyo (japon) *pseudogyroporella mizziaformis endo 1959, nom. nud. 1 9 5 9 (nom. nud.) pseudogyroporella mizziaformis n. gen. n. sp.endo, pl. 30, fig. 3.hatahoko, nyūg a w a m u r a , o _ no-gun, gifu-ken, honshū (japon): permien (gonbō fm, zone à p a r a f u s u l i n a = zone à p s e u d o s c h w a g e r i n a [s i c]); pl. 30, fig. 4.ozudani valley, nyūgawa-mura, o _ no-gun, gifu-ken, honshū (japon): permien inférieur (gonbō fm, zone à p s e u d o s c h w a g e r i n a ).“holotype” (syntypes): pl. 30, fig. 3, lame mince n° 21132; pl. 30, fig. 4, lame mince n° 21112, geol. min. inst., tokyo kyoiku daigaku [tokyo university of education ] (japon) 1961a (nom. nud.) pseudogyroporella mizziaformis.endo, pl. 2, fig. 7, extrait de endo (1959: pl. 30, fig. 3) 1961b (nom. nud.) pseudogyroporella mizziaformis.endo, pl. 5, fig. 1-2.w nagaoka, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 5, fig. 3.sukawa, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm) 1962 (nom. nud.) pseudogyroporella mizziaformis.kochansky-devidé & milanoviê, pl. vii, fig. 1-3.sjerogoπte, rivière tara, monténégro (yougoslavie): sakmarien supérieur ou artinskien inférieur 1963 (nom. nud.) pseudogyroporella mizziaformis.johnson, pl. 71, fig. 5-6.(japon): permien “inférieur” 1 9 6 9 (nom. nud.) pseudogyroporella mizziaformis.endo, pl. xv, fig. 2-4.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina ) 1 9 7 1 (nom. nud.) pseudogyroporella mizziaformis.ishijima et al., pl. 4, fig. 1.sakaishimachibun, agano-mura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur” 1 9 7 9 (nom. nud.) pseudogyroporella mizziaformis.ramovπ & kochansky-devidé, pl. 2, fig. 1.n julijske alpe (slovénie): carbonifère, silésien, gzhélien (oberer auernigschichten); pl. 2, fig. 2 & 3 pars.n julijske alpe (slovénie): artinskien (trogkofelkalk) 1 9 7 9 a (nom. nud.) pseudogyroporella mizziaformis.roux, pl. 21, fig. 4 & 6.n otto fiord, ellesmere, nunavut (canada): carbonifère, silésien (fm nansen); pl. 21, fig. 5.griesbach, axel heiberg, nunavut (canada): sakmarien (fm nansen) 1 9 8 1 (nom. nud.) pseudogyroporella mizziaformis.nakamura, pl. 7, fig. 3; pl. 9, fig. 7.ishiyama, o _ n o c hō tanigumi-mura, gifu-ken, honshū (japon): permien (ishiyama limestone) 1 9 8 2 (nom. nud.) pseudogyroporella mizziaformis.mu, pl. vii, fig. 1-3.xizang / tibet (chine populaire): carbonifère, silésien 1 9 8 7 (nom. nud.) pseudogyroporella mizziaformis.mamet et al., pl. 21, fig. 4-6, extrait de roux (1979a: pl. 21, fig. 4-6) 1 9 8 8 (nom. nud.) pseudogyroporella mizziaformis.deloffre, pl. 8, fig. 10, extrait de kochansky-devidé & milanoviê (1962: pl. vii, fig. 1) pseudogyroporella ohnoensis nakamura 1981 , nom. nud. 1981 (nom. nud.) pseudogyroporella ohnoensis n. sp.nakamura, pl. 8, fig. 1-10.ishiyama, o _ no-chō tanigumimura, gifu-ken, honshū (japon): permien (ishiyama limestone).syntype (s): pl. 8, fig. 1-2, 6 & 10, lames minces n° nsm-pp 6909-1, 6935-8, 6939-1 & 6939-2, national science museum, tokyo (japon) 147granier & grgasoviê: les algues dasycladales du permien et du trias... pseudogyroporella rotunda ishijima et al. 1971, nom. nud. 1 9 7 1 (nom. nud.) pseudogyroporella rotunda n. sp.ishijima et al., pl. 6, fig. 4-6.sakaishimachibun, aganomura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur”.holotype: pl. 6, fig. 4, spécimen n° nsmp1-18130c, national science museum, tokyo (japon) pseudovelebitella mamet et roux 1978 *pseudovelebitella simplex (kochansky-devidé 1964) mamet et roux 1978 [= velebitella simplex kochansky-devidé 1964 ] 1964a velebitella simplex n. sp.kochansky-devidé, pl. ii, fig. 1.papuëa, medak, velebit mt (croatie): carbonifère, silésien, gzhélien (triticitensandstein); pl. ii, fig. 2-9.mliniπte, oπljak, radina kosica & raduë, sv. rok, lika (croatie): permien inférieur (base rattendorfer schichten).holotype: pl. ii, fig. 2, lame mince n° 2217, collection v. kochansky-devidé, geoloπko-paleontoloπki zavod, prirodoslovno-matematiëki fakultet [geological and palaeontological institute, faculty of sciences ], zagreb (croatie) 1964b velebitella simplex.kochansky-devidé, pl. 19, fig. 1, extrait de kochansky-devidé (1964a: pl. ii, fig. 2) 1977 velebitella sp.vachard in h. termier et al., pl. 2, fig. 7.djebel tebaga (tunisie): murghabien 1978b pseudovelebitella simplex n. gen. n. comb.mamet & roux, p. 75, non figurée 1985 velebitella simplex.vachard, pl. 2, fig. 5.djebel tebaga (tunisie): murghabien supérieur; pl. 2, fig. 67.djebel tebaga (tunisie): murghabien supérieur fig. 24 velebitella simplex (kochansky-devidé, 1964a, pl. ii, fig. 3), x66. fig. 25 velebitella simplex (kochansky-devidé, 1964a, pl. ii, fig. 2), x66. 148 geologia croatica 53/1 salopekiella milanovi∆ in granier et deloffre 1995, non 1965 salopekiella breziki milanovi∆ 1975, nom. nud. [cf. uragiellopsis breziki milanovi∆ ex vachard 1980 ] salopekiella ? kochanskae milanovi∆ 1968, nom. nud. [cf. clavaporella kochanskae milanovi∆ ex vachard 1980 ] *salopekiella velebitana milanovi∆ in granier et deloffre 1995, non 1965 1965a (nom. nud.) salopekiella velebitana n. gen. n. sp.milanoviê, fig. 2, 3.a-b & 4; pl. i, fig. 1 [= fig. 3.a]; pl. i, fig. 3-9; pl. ii, fig. 1-10; pl. iii, fig. 1-9.crno vrelo, sw medak, velebit mt (croatie): permien “moyen”-”supérieur”; pl. i, fig. 2.velebit mt (croatie): permien “moyen”-”supérieur”.syntypes: pl. i, fig. 1; pl. ii, fig. 5-6, lame mince n° br-8b; pl. i, fig. 7, lame mince n° 4507/1, collection m. milanoviê, institut za geoloπka istraæivanja [institute of geology ], zagreb (croatie) 1 9 6 5 b (nom. nud.) salopekiella velebitana.milanoviê, fig. 1.a, extrait de milanoviê (1965a: pl. i, fig. 1 = fig. 3.a); fig. 1.b, extrait de milanoviê (1965a: pl. ii, fig. 1) 1968b non (nom. nud.) salopekiella cf. velebitana [= likanella longispinosa].endo, pl. i, fig. 5 1969 (nom. nud.) salopekiella velebitana .endo, pl. xxxviii, fig. 8-9; pl. xxxix, fig. 1-5.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina zone à neoschwagerina simplex / partie inférieure) 1970a (?) ortonella morikawai .kochansky-devidé, pl. xxii, fig. 1-2; pl. xxiv, fig. 1 pars & 2 pars.w karavanke (slovénie): sakmarien (trogkofelkalk) 1 9 7 2 (?) (nom. nud.) salopekiella cf. v e l e b i t a n a .homann, pl. 7, fig. 56-58.nw zottach-kogel, kärnten (autriche): sakmarien (rattendorfer schichten, oberer pseudoschwagerinenkalk) 1 9 8 4 (?) (nom. nud.) salopekiella sp.e. flügel, kochansky-devidé & ramovπ, pl. 29, fig. 7.bled (slovénie): permien “moyen” 1986 (?) ortonella morikawai .milanoviê, pl. iii, fig. 5 & 7.gorski kotar (croatie): permien “inférieur””moyen” 1 9 9 1 (nom. nud.) salopekiella velebitana.sremac, pl. 2, fig. 3.bruπane, baπke oπtarije, velebit mt (croatie): murghabien (zone à neoschwagerina craticulifera ) 1 9 9 2 (?) (nom. nud.) salopkiella c f . v e l e b i t a n a.vachard et al., pl. iii, fig. 4 pars.s doi luang mts, nw thaïlande (thaïlande): bolorien 1995 salopekiella velebitana .milanoviê in granier & deloffre, p. 57, non figurée.typification et validation de l’espèce; lectotype: pl. i, fig. 1 in milanoviê (1965a), lame mince n° br-8b, collection m. milanoviê, institut za geoloπka istraæivanja [institute of geology ], zagreb (croatie) salpingoporella pia in trauth 1917, emend. conrad et al. 1973 salpingoporella humilis (bystrický 1967) ott 1974 [= macroporella humilis bystrický 1967] 1967b m a c r o p o r e l l a (p i a n e l l a ) h u m i l i s n. sp.bystrický, pl. iii, fig. 4-5; pl. iv, fig. 5.w silická brezová, s l o v e n s ký kras (slovaquie): carnien (wettersteinkalk), julien, ou d’après bystrický (1986): c a r n i e n , julien (andrusoporella duplicata taxon-range zone).holotype: pl. iii, fig. 4, lame mince n° 2413, collection j. bystricky´, geological institute, slovak academy of sciences, bratislava (slovaquie) 1974 salpingoporella humilis n. comb.ott, p. 27, non figurée 1976 (?) m a c r o p o r e l l a cf. h u m i l i s.miπík & borza, pl. iii, fig. 2.silická brezová, slovenský kras (slovaquie): carnien salpingoporella spectabilis (bystrický 1962) emberger 1979 [= macroporella spectabilis bystrický 1962] 1962 macroporella spectabilis n. sp.bystrický, pl. iii, fig. 1-3.rybník, n budikovaný, w pleπivec (slo149granier & grgasoviê: les algues dasycladales du permien et du trias... vaquie): trias moyen, ? ladinien supérieur.holotype: pl. iii, fig. 1, lame mince n° 1582, collection j. bystricky´, geologický ústav dioný za ©túra, bratislava (slovaquie) 1964 macroporella spectabilis .bystrický, pl. vi, fig. 5, extrait de bystrický (1962: pl. iii, fig. 3); pl. vi, fig. 6, extrait de bystrický (1962: pl. iii, fig. 2); pl. vi, fig. 4 pars (droite), extrait de bystrický (1962: pl. iii, fig. 1); pl. vi, fig. 4 pars (gauche) & 7.rybník, n budikovaný, w pleπivec (slovaquie): trias moyen, ? ladinien (wettersteinkalk) 1969 macroporella spectabilis .diaconu & dragastan, pl. ii, fig. 3; pl. v, fig. 2.dealul glimeia, apuseni mts (roumanie): ladinien 1973 macroporella spectabilis .popa & dragastan, pl. xix, fig. 74.dealul ruget remeţi, w valea boiului, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien-ladinien, illyrien supérieur langobardien 1979 macroporella spectabilis .bystrický, pl. i, fig. 1 & 3-4.remiaπka, n stratená, n dobπiná, stratenská hornatina mts (slovaquie): carnien terminal (tisoveckalk); pl. i, fig. 2; pl. ii, fig. 1-2 & 4.colline kopa, n stratená, n dobπiná, stratenská hornatina mts (slovaquie): trias supérieur, ? norien (? furmaneckalk) 1979 salpingoporella spectabilis n. comb.emberger, p. 49 & 74, non figurée 1983 macroporella spectabilis .schäfer & senowbari-daryan, pl. 6, fig. 2 pars (2).didymi mts, argolís (grèce): trias supérieur 1986 macroporella spectabilis .bystrický, pl. v, fig. 5.budikovaný, w pleπivec (slovaquie): carniennorien, julien-lacien (andrusoporella duplicata taxon-range zone et h e t e r o p o r e l l a taxon-range superzone) 1988 (?) teutloporella ex gr. herculea .vachard & fontaine, pl. iii, fig. 1-2 & 5-6.khao cha ang on, n klaeng (thaïlande): ladinien salpingoporella sturi (bystrický 1967) emberger 1979 [= macroporella sturi bystrický 1967] 1967b m a c r o p o r e l l a (p i a n e l l a ) s t u r i n. sp.bystrický, pl. ii, fig. 4; pl. iii, fig. 1-3; pl. iv, fig. 1-3.w silická brezová, slovenský kras (slovaquie): carnien (wettersteinkalk), julien.holotype: pl. iii, fig. 1, lame mince n° 2813, collection j. bystrick ý, geological institute, slovak academy of sciences, bratisla va (slovaquie) 1970 (?) macroporella (p i a n e l l a ) aff. s t u r i.patrulius, pl. iv, fig. 1-2.piatra şoimului, mt rarǎu, suceava (roumanie): norien 1979 macroporella sturi .bystrický, pl. iii, fig. 4-5.vernár, nízke tatry (slovaquie): carnien, tuvalien (tisoveckalk) 1979 salpingoporella sturi n. comb.emberger, p. 49 & 75, non figurée 1986 macroporella sturi .bystrický, pl. v, fig. 4, extrait de bystrický (1967b: pl. iii, fig. 1); pl. v, fig. 7.silická brezová, slovenský kras (slovaquie): carnien, julien (andrusoporella duplicata taxon-range zone) salpingoporella ? tibetica e. flügel et mu 1982 1982 salpingoporella ? tibetica n. sp.e. flügel & mu, pl. 8, fig. 1-4, 5 pars & 6.jomda, qambdo district, e xizang / tibet (chine populaire): carnien (jiapeila fm).holotype: pl. 8, fig. 1-2, lame mince n° 76 cj 9, nanjing institute of geology and paleontology, academia sinica, nanjing (chine populaire) samarella maslov et kulik ex kulik 1964 [synonyme postérieur de uraloporella kordé 1950, d’après vachard & h. et g. termier, 1977 ] samarella massieuxae güvenç 1966, nom. nud. [“synonyme” de uraloporella variabilis kordé 1950, emend. mamet et villa 1995, d’après mamet et roux in mamet et al. , 1987] 150 geologia croatica 53/1 *samarella setosa maslov et kulik ex kulik 1964 [synonyme postérieur de uraloporella variabilis kordé 1950, emend. mamet et villa 1995, d’après vachard & h. et g. termier, 1977 ] shigaporella endo 1961, nom. nud. *shigaporella exortiva endo 1961, nom. nud. 1 9 6 1 b (nom. nud.) shigaporella exortiva n. gen. n. sp.endo, pl. 16, fig. 4.muraki, ibuki-mura, santōm a c h i , sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 17, fig. 7.make, kitatominaga-mura, higashi-asai-gun, shiga-ken, honshū (japon): permien “inférieur” (lower takayama fm); pl. 17, fig. 8.iwakura-yama, sekigahara-machi, fuwa-gun, gifu-ken, honshū (japon): permien “moyen” / partie inférieure (ibukiyama limestone fm / partie inférieure).“holotype” (syntypes): pl. 16, fig. 4, lame mince n° 510603-1; pl. 17, fig. 7, lame mince n° 520417-2, geological survey of japan (japon) 1963 (nom. nud.) shigaporella exortiva .johnson, pl. 71, fig. 1, extrait de endo (1961b: pl. 17, fig. 8); pl. 71, fig. 2, extrait de endo (1961b: pl. 17, fig. 7) 1971 (nom. nud.) shigaporella exortiva .ishijima et al., pl. 12, fig. 2-3.sakaishimachibun, agano-mura, hannōshi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur” sphenoporella chuvashov in chuvashov et anfimov 1988 *sphenoporella sphenopora (chuvashov 1974) in chuvashov et anfimov 1988 [= epimastopora ? sphaenopora chuvashov 1974 ] 1974 epimastopora ? sphaenopora n. sp.chuvashov, pl. x, fig. 1-3.rivière chigishan, w yekaterinburg, w oural (fédération de russie): assélien.holotype: pl. x, fig. 1, lame mince n° π 208-47, collection b.i. chuvashov, unt ai sssr [institute of geology and geochemistry of urals, section of russian academy of sciences ], yekaterinburg (fédération de russie) 1988 sphenoporella sphenopora n. gen. n. comb.chuvashov in chuvashov & anfimov, pl. xxiii, fig. 1-2.extrait de chuvashov (1974: pl. x, fig. 1-2) spinaporella e. flügel et flügel-kahler in e. flügel, flügel-kahler et al. 1984 *spinaporella andalusica e. flügel et flügel-kahler in e. flügel, flügel-kahler et al. 1984 1935b spongien (?).pia in schmidt, pl. ii, fig. 3-5.río dílar, ese dílar sse la zubia, granada (espagne): trias 1980 griphoporella curvata .martin & delgado, fig. 4.pico de la carne, sse monachil se la zubia, granada (espagne): norien 1980 (?) dasycladacean.martin & delgado, fig. 6-10.pico de la carne, sse monachil se la zubia, granada (espagne): norien 1984 spinaporella andalusica n. gen. n. sp.e. flügel & flügel-kahler in e. flügel, flügel-kahler et al., pl. 20; pl. 21, fig. 1-6 & 8; pl. 22, fig. 1-9.pico de la carne, sse monachil se la zubia, granada (espagne): trias moyen, ? ladinien; pl. 21, fig. 9, extrait de pia (1935b: pl. ii, fig. 4); pl. 21, fig. 10, extrait de pia (1935b: pl. ii, fig. 3); pl. 21, fig. 11, extrait de pia (1935b: pl. ii, fig. 5).holotype: pl. 21, fig. 3 [= pl. 20 pars ], échantillon 8b, lame mince n° sm.b. 13499, paläobotanische abteilung, forschungsinstitut senckenberg, frankfurt am main (allemagne) 1987 spinaporella andalusica .braga & martin, pl. i, fig. 5 & 10.pico de la carne, sse monachil se la zubia, granada (espagne): norien 1989 (?) dasycladacean.martin & braga, pl. 2, fig. 1.pico de la carne, sse monachil se la zubia, granada (espagne): trias supérieur; pl. 2, fig. 2-3, extrait de martin & delgado (1980: fig. 6 & 10) 151granier & grgasoviê: les algues dasycladales du permien et du trias... 1999 spinaporella andalusica .parente & climaco, pl. 39, fig. 2 pars; pl. 40, fig. 1-2 & 7-8.mte rotonda, e maratea, basilicata (italie): trias supérieur (norien) spinaporella ? granadaensis e. flügel et flügel-kahler in e. flügel, flügel-kahler et al. 1984 1984 spinaporella granadaensis n. sp.e. flügel & flügel-kahler in e. flügel, flügel-kahler et al., pl. 21, fig. 7.pico de la carne, sse monachil se la zubia, granada (espagne): trias moyen, ? ladinien; pl. 23, fig. 1-4; pl. 30, fig. 2.cahorros de monachil, ese monachil, granada (espagne): trias moyen, ? l a d i n i e n.holotype: pl. 23, fig. 3, échantillon tch-10a, lame mince n° sm.b. 13500, forschungsinstitut senckenberg, paläobotanische abteilung, frankfurt am main (allemagne) 1987 spinaporella ? g r a n a d a e n s i s .braga & martin, pl. i, fig. 8.cahorros de monachil, ese monachil, granada (espagne): norien 1999 spinaporella ? granadaensis .parente & climaco, pl. 40, fig. 3 & 5.mte rotonda, e maratea, basilicata (italie): trias supérieur (norien) stolleyella schubert 1909, non 1907 [synonyme postérieur de vermiporella stolley 1893, d’après pia, 1920 ] *stolleyella velebitana schubert 1909 [cf. vermiporella velebitana (schubert 1909) pia 1920 ] stolleyella yabei karpinsky 1909 [cf. mizzia yabei (karpinsky 1909) pia 1920 ] terquemella munier -chalmas ex l. et j. morellet 1913 terquemella brentai pugliese 1997 1997 terquemella brentai n. sp.pugliese, pl. 2, fig. 10-24.croz dell’altíssimo, n lago di molveno, e madonna di campíglio, gruppo di brenta, trentino alto adige (italie): rhétien.holotype: pl. 2, fig. 24, lame mince cr 68, collection a. pugliese, n° mpum 8067-8071, dipartimento di scienze della terra, università degli studi di milano (italie) teutloporella pia 1912, emend. bassoullet et al. 1978 teutloporella aequalis (gümbel 1872) pia 1920 [synonyme postérieur de teutloporella herculea (stoppani 1857) pia 1912, d’après ott, 1963 ] teutloporella aequalis var. gracilis michard 1962, nom. nud. [variété superflue ] teutloporella echinata ott 1975, nom. nud. 1975 (nom. nud.) teutloporella echinata n. sp.ott, fig. 2.a-b; pl. 10, fig. 1-2.forage monte ário, s cóllio nw pertica bassa, e val trómpia, lombardia (italie): ladinien (esinokalk / fm del calcare di esino). “holotyp” (syntypes): fig. 2.b; pl. 10, fig. 1, lame mince ario 3, collection e. ott, bayerische staatssammlung für paläontologie und historische geologie, münchen (allemagne) 1980 (?) calcareous algae.martin & delgado, fig. 5.pico de la carne, sse monachil se la zubia, granada (espagne): norien 1981b (?) teutloporella sp.p. di stefano, fig. 29.e.cozzo di lupo, torretta, s carini, w palermo, sicile (italie): norien 1982 (?) teutloporella sp.abate et al., fig. 11.e, extrait de p. di stefano (1981b: fig. 29.e) 152 geologia croatica 53/1 1983 (?) connexia sp.schäfer & senowbari-daryan, pl. 6, fig. 5.ídhra / hydra (grèce): trias supérieur 1984 teutloporella sp.henrich, pl. 9, fig. 1.hochstaufen, hochstaufen-zwieselmassif, w salzburg, bayern (allemagne): carnien, cordevolien (wettersteinkalk) 1985 (?) (nom. nud.) teutloporella cf. t. echinata .p. di stefano & senowbari-daryan, pl. iii, fig. 3-4.cozzo di lupo, torretta, s carini, w palermo, sicile (italie): norien; pl. iii, fig. 7, extrait de p. di stefano (1981b: fig. 29.e) 1 9 8 9 (nom. nud.) teutloporella echinata .buëek, pl. ii, fig. 5.buková, malé karpaty (slovaquie): ladinien (wettersteinkalk) 1991 (?) connexia sp.e. flügel et al., pl. 47, fig. 4 pars.pietra di salomone, sw palazzo adriano, sw prizzi, sicile (italie): permien teutloporella gigantea pia 1912 [synonyme postérieur de teutloporella herculea (stoppani 1857) pia 1912, d’après pia, 1920 ] *teutloporella herculea (stoppani 1857) pia 1912 [= diplopora herculea (stoppani 1857) salomon 1895; d’abord considérée comme un bivalve perforant: gastrochaena herculea stoppani 1857 ] 1857 gastrochaena herculea n. sp.stoppani, p. 376-377, non figurée.type non figurée 1857 gastrochaena gracilis n. sp.stoppani, p. 376, non figurée.type non figurée 1858 gastrochaena herculea .stoppani, pl. 16, fig. 11-12.“val di cino”, cino, ne lago di como, lombardia (italie): trias moyen (esinokalk / fm del calcare di esino) 1858 gastrochaena gracilis .stoppani, pl. 16, fig. 13.“val di cino”, cino, ne lago di como, lombardia (italie): trias moyen (esinokalk / fm del calcare di esino) 1872 gyroporella aequalis n. sp.gümbel, pl. d.iii, fig. 14.a-c.rohrbach im oberösterreich, nw linz, oberösterreich (autriche): trias moyen (wetterlingkalk); pl. d.iv, fig. 1.a-g.hötting, innsbruck, tirol ( a u t r i c h e ).types: pl. d.iv, fig. 1.a-g, collection c.w. gümbel (coll. prof. pichler), münchen (allemagne) 1877 gyroporella aequalis .karrer, pl. xvi.b, fig. 14-14.a.höllental, niederösterreich (autriche): trias ? moyen (wettersteinkalk) 1877 gyroporella multiserialis .karrer, pl. xvi.b, fig. 15.höllental, niederösterreich (autriche): trias ? moyen (wettersteinkalk) 1895 diplopora herculea n. comb.salomon, pl. i, fig. 13-19.marmolada, trentino alto adige véneto (italie): trias moyen (esinokalk / fm del calcare di esino) 1899 diplopora herculea .tommasi, pl. i, fig. 1.mte clapsavon, ne forni di sopra nw forni di sotto, w ampezzo, friuli venezia giulia (italie): trias 1912 teutloporella gigantea n. sp.pia, pl. iii(ii), fig. 3-4.wetterstein, tirol (autriche): trias ? moyen (wettersteinkalk); pl. iii(ii), fig. 5-6.hall in tirol-bettelwurfspitze, tirol (autriche): trias ? moyen (wetters t e i n k a l k ).types: pl. iii(ii), fig. 3, lame mince n° lxxx/6; pl. iii(ii), fig. 4, lame mince n° lxxx/1; pl. iii(ii), fig. 5-6, lame mince n° lviii/1, collection j. von pia, naturhistorisches muse um, wien (autriche) 1912 teutloporella herculea n. comb.pia, pl. ii(i), fig. 27.wegscheid, rammertal, steiermark (autriche): trias ? moyen (wettersteinkalk); pl. iii(ii), fig. 1.schiestlhaus, hochschwab, steiermark (autriche): trias ? moyen (wettersteinkalk); pl. iii(ii), fig. 2.drei-markstein, raxalpe, steiermark (autriche): trias ? moyen (wettersteinkalk) 1920 teutloporella herculea .pia, pl. ii, fig. 16.mühlau, innsbruck, tirol (autriche): ladinien; pl. ii, fig. 17.esino lario, e lago di como, lombardia (italie): ladinien (esinokalk / fm del calcare di esino); pl. ii, fig. 18.wildanger, hall in tirol, tirol (autriche): ladinien (wettersteinkalk) 1927 teutloporella herculea .ogilvie gordon, pl. ix, fig. 4.a-b; pl. x, fig. 14.val di fassa, trentino alto adige (italie): buchensteiner kalk, marmolatakalk 1937 teutloporella herculea .andrusov, fig. 1; pl. i, fig. 2.zlatno, muráňska planina (slovaquie): ladinien (wettersteinkalk) 1940c teutloporella herculea .pia, pl. 4, fig. 10; pl. 5, fig. 11-13.höllengebirge, oberösterreich (autriche): ladinien (wettersteinkalk) 153granier & grgasoviê: les algues dasycladales du permien et du trias... 1950 teutloporella herculea .herak, pl. i, fig. 4.planina, krndija mt (croatie): ladinien; pl. iii, fig. 1 & 4.koprivnjaëa, durmitor mts, monténégro (yougoslavie): ladinien 1954 teutloporella herculea .rosenberg & zapfe in götzinger et al., pl. 1, fig. 12.a-b.habsburgerhaus, höllengebirge, oberösterreich (autriche): ladinien (wettersteinkalk) 1957 teutloporella aequalis .bystrický, pl. iii, fig. 1.se rarbok, sw vajarská hora, malé karpaty (slovaquie): ladinien inférieur; pl. iii, fig. 2.©tvrtská pila, stratenská hornatina mts (slovaquie): ladinien inférieur (choë-dolomit); pl. iii, fig. 3.holý vrch bartalik, stratenská hornatina mts (slovaquie): ladinien inférieur 1957 teutloporella herculea .bystrický, pl. iii, fig. 4-5 & 8.dolný vrch silická planina, slovenský k r a s (slovaquie): ladinien; pl. iii, fig. 6.glac, stratenská hornatina mts (slovaquie): ladinien; pl. iii, fig. 7.bikarky, hrabuπice, stratenská hornatina mts (slovaquie): ladinien 1958 teutloporella herculea .mahel’, pl. ix, fig. 3.bikarky, hrabuπice, stratenská hornatina mts (slovaquie): ladinien 1959 teutloporella herculea .andrusov, pl. xi, fig. 2, extrait de andrusov (1937: pl. i, fig. 2) 1961 teutloporella herculea .pantiê, pl. i, fig. 1-3; pl. ii, fig. 3.koprivnik, krπ »vrlje, prokletije mts, kosovo, serbie (yougoslavie): ladinien; pl. ii, fig. 1-2.kik, sokol mt, w serbie (yougoslavie): ladinien 1 9 6 2 a (nom. nud.) teutloporella aequalis var. g r a c i l i s n. var.michard, pl. iv, fig. 1-2.valle di cavoira, val grana, piemonte (italie): ladinien .types: pl. iv, fig. 1-2, collection a. michard, office national de gestion des collections paléontologiques, villeurbanne (france) 1 9 6 2 a (nom. nud.) teutloporella herculea var. g r a c i l e ? [s i c].michard, pl. iv, fig. 3.valle di cavoira, val grana, piemonte (italie): ladinien 1963 teutloporella herculea .ott, fig. 25.speckkarspitze, karwendelgebirge, tirol (autriche): ladinien (wettersteinkalk) 1964 teutloporella aequalis .bystrický, pl. iii, fig. 2.s vëeláre, dolný vrch, slovenský kras (slovaquie): ladinien, fassanien, ou d’après bystrický (1986): ladinien, fassanien (diplopora annulata t a x o n r a n g e zone); pl. iii, fig. 3.s vëeláre, dolný vrch, slovenský kras (slovaquie); pl. iii, fig. 4.slovenský k r a s (slovaquie) 1964 teutloporella herculea .bystrický, pl. ii, fig. 1-2.s vëeláre, dolný vrch, slovenský kras (slovaquie); pl. ii, fig. 3; pl. iv, fig. 5.silická planina, slovenský kras (slovaquie); pl. ii, fig. 4; pl. iii, fig. 1; pl. iv, fig. 3-4.slovenský kras (slovaquie) 1965 teutloporella herculea .andrusov, fig. 30, extrait de andrusov (1937: pl. i, fig. 2); fig. 31, extrait de andrusov (1937: fig. 1) 1965 (?) teutloporella herculea .»anoviê, pl. 2, fig. 4; pl. 3, fig. 3.forage grahovo-1 (gr-1), grahovo, osjeëenica, monténégro (yougoslavie): ladinien 1965 teutloporella aequalis .herak, pl. xiv, fig. 7.spodnja radovna-krnica (slovénie): trias moyen; pl. xiv, fig. 8.nnw peêina ponor, sv. rok, lika (croatie): trias moyen 1965 teutloporella herculea .herak, pl. v, fig. 1.popov do, ljubiπnja mt, monténégro (yougoslavie): ladinien; pl. v, fig. 2.oëura, golubovec, hrvatsko zagorje (croatie): ladinien 1965 teutloporella herculea .schalekova, pl. xxxvi, fig. 2.vajarská hora, malé karpaty (slovaquie): ladinien 1965a teutloporella herculea .zanin buri, pl. 42, fig. 1-2; pl. 43, fig. 1-3.sas carlên, esino lario, e lago di como, lombardia (italie): ladinien supérieur (esinokalk / fm del calcare di esino) 1966 teutloporella aequalis .miπík, pl. vi, fig. 1.a-b, extrait de bystrický (1964: pl. iii, fig. 2 & 4) 1966 teutloporella herculea .ott, fig. 6.schlauchkar, karwendelgebirge, tirol (autriche): ladinien (wettersteinkalk) 1967b (?) teutloporella ex aff. h e r c u l e a .bystrický, pl. i, fig. 7; pl. ii, fig. 2.muráňska huta, muráňska planina (slovaquie): carnien (tisoveckalk); pl. ii, fig. 1.w tisovec, muráňska planina (slovaquie): norien (furmaneckalk) 1967a diplopora cf. annulata .herak, pl. 9, fig. 3-4.khíos / chios (grèce): ladinien 1967a teutloporella herculea .herak, pl. 7, fig. 1-2.ligaridi, khíos / chios (grèce): ladinien 1 9 6 7 (nom. nud.) teutloporella aequalis var. g r a c i l i s .michard, pl. ix, fig. 1, extrait de michard (1962a: pl. iv, fig. 1 pars); pl. ix, fig. 2.valle di cavoira, val grana, piemonte (italie): ladinien 1967 teutloporella herculea .michard, pl. ix, fig. 3, extrait de michard (1962a: pl. iv, fig. 3) 154 geologia croatica 53/1 1967 teutloporella herculea .pantiê, pl. vi, fig. 1-4.©ljivovica, tara mt, w serbie (yougoslavie): ladinien 1968 teutloporella herculea .dimitrijeviê et al. (pantiê), pl. i.b; pl. v, fig. 9-10.s tjentiπte, n gacko, sutjeska (bosnie-herzégovine): ladinien 1969 teutloporella herculea .diaconu & dragastan, pl. ii, fig. 4.dealul glimeia, apuseni mts (roumanie): ladinien 1970 teutloporella herculea .büchner, fig. 17-18.johnsbachtal, n johnsbach, gesäuse, steiermark (autriche): ladinien (wettersteinkalk) 1972 (?) teutloporella cf. herculea .»anoviê & kemenci, pl. ii, fig. 8.forage velebit-2 (ve-2), senta-subotica, vojvodina, serbie (yougoslavie): ladinien 1972 teutloporella herculea .kodra, pl. 2, fig. 6.prozhmë, kollatë, valbona (albanie): ladinien (suita e selimajt) 1973 teutloporella herculea .bulle, pl. i, fig. 1-7.se gaber vrh, titov veles (macédoine): ladinien 1973 teutloporella aequalis .kotański, pl. v, fig. 1.tiesniawy gorge, koryciska scale, juránová valley, se oravice, tatry (slovaquie): ladinien (wettersteindolomit) 1973 teutloporella herculea .kotański, pl. iv, fig. 1-2; pl. v, fig. 6-7; pl. vi, fig. 3 pars.dolina male koryciska, koryciska scale, w zakopane, tatry (pologne): ladinien (wettersteindolomit); pl. v, fig. 5; pl. vi, fig. 4 pars.tiesniawy gorge, koryciska scale, juránová valley, se oravice, tatry (slovaquie): ladinien (wettersteindolomit) 1973 teutloporella herculea .wolff, pl. 5, fig. 5.wendelstein kampenwand, bayern (allemagne): ladinien 1975 t e u t l o p o r e l l a h e r c u l e a .pantiê-prodanoviê, pl. xliii, fig. 1 pars; pl. l, fig. 2 pars.»vrlja, prokletije mts, kosovo, serbie (yougoslavie): ladinien; pl. xliv, fig. 1 pars.©ljivovica, tara mt, w serbie (yougoslavie): ladinien 1976 teutloporella herculea .hanáëek, pl. vi, fig. 4; pl. ix, fig. 4.priedhorie, stráæovské vrchy, e trencín (slovaquie): ladinien (wettersteinkalk); pl. ix, fig. 2 & 3 pars.stráæovské vrchy, e trencín (slovaquie): carnien, cordevolien (wettersteinkalk) 1978 teutloporella herculea .e. flügel, pl. 25 pars.amtmanngalgen, johnsbach, gesäuse, steiermark (autriche): ladinien (wettersteinkalk) 1979 teutloporella aequalis .kotański, pl. 80, fig. 3.tatry (pologne): ladinien inférieur 1979 teutloporella herculea .kotański, pl. 80, fig. 1, 2.e & 4-5.tatry (pologne): ladinien inférieur 1980 teutloporella herculea .dragastan, pl. vi, fig. 8 pars.glimeia, pǎdurea craiului, apuseni mts, bihor (roumanie): ladinien; pl. vii, fig. 4.forage sterpinoasa, pǎdurea craiului, apuseni mts, bihor (roumanie): ladinien 1982 teutloporella herculea .e. flügel, pl. 33 pars, extrait de e. flügel (1978: pl. 25 pars) 1982 teutloporella herculea .e. flügel & mu, pl. 8, fig. 7.jomda, qambdo district, e xizang / tibet (chine populaire): carnien (jiapeila fm) 1984 teutloporella herculea .e. flügel, flügel-kahler et al., pl. 23, fig. 8; pl. 27, fig. 5.cahorros de monachil, ese monachil, granada (espagne): trias moyen, ? ladinien; pl. 23, fig. 9-10.pico de la carne, sse monachil se la zubia, granada (espagne): trias moyen, ? ladinien 1985 teutloporella hercula [s i c].dragastan et al., pl. 1, fig. 8.mesopótamos, messinía (grèce): ladinien (calcaires à “cardita ”) 1986 teutloporella aequalis .bystrický, pl. iv, fig. 5, extrait de bystrický (1964: pl. iii, fig. 2) 1986 teutloporella herculea .bystrický, pl. iv, fig. 7.priepast laviëka, silická brezová, slovenský k r a s (slovaquie): ladinien-carnien (diplopora annulata taxon-range zone, teutloporella herculea i n t e r v a l zone et andrusoporella duplicata taxon-range zone); pl. v, fig. 9.silická brezová, slovenský kras (slovaquie): ladinien-carnien (diplopora annulata taxon-range zone, teutloporella herculea interval zone et andrusoporella duplicata taxon-range zone) 1986 teutloporella aequalis .kotański, pl. civ, fig. 3, extrait de kotański (1979: pl. 80, fig. 3) 1986 teutloporella herculea .kotański, pl. civ, fig. 1, 2.e & 4-5, extrait de kotański (1979: pl. 80, fig. 1, 2.e & 4-5) 1988 teutloporella herculea .»anoviê & kemenci, pl. ix, fig. 1.forage velebit-2 (ve-2), senta-subotica, vojvodina, serbie (yougoslavie): ladinien 1988 teutloporella herculea .turek, marek & benes, p. 61, fig. 3.dobπiná, stratenská hornatina mts (slovaquie): anisien-ladinien 155granier & grgasoviê: les algues dasycladales du permien et du trias... 1988 non teutloporella ex gr. herculea [= ? macroporella spectabilis ].vachard & fontaine, pl. iii, fig. 1-2 & 5-6 1989 teutloporella aequalis .buëek, pl. iii, fig. 2.rohoæník, vajarská hora, malé karpaty (slovaquie): ladinien (wettersteinkalk) 1989 teutloporella herculea .buëek, pl. iii, fig. 1 & 3.rohoæník, vajarská hora, malé karpaty (slovaquie): ladinien (wettersteinkalk) 1994 teutloporella herculea .boni et al., pl. 17, fig. 4-5.piano caramolo-la picarella, mte caramolo, w castrovillari, n san donato, calabria (italie): ladinien ? carnien teutloporella ? hidensis endo et horiguchi 1957 1957 teutloporella ? hidensis n. sp.endo & horiguchi, pl. xv, fig. 4-5.kamitakara-mura, fukuji, gifu-ken, h o n s hū (japon): permien inférieur (ichinotani group, zone à p s e u d o s c h w a g e r i n a ).holotype: pl. xv, fig. 4, lame mince n° 604; “syntype” (paratype): pl. xv, fig. 5, lame mince n° 604, department of earth sciences, saitama university, urawa (japon) teutloporella hirsuta pia 1935 teutloporella hirsuta var. hirsuta pia 1935 [par accident ! ] 1935a teutloporella hirsuta n. sp.pia, pl. iii, fig. 5-7.nw blizanac, trebeviê, s sarajevo (bosnie-herzégovine): anisien, pelsonien.type: pl. iii, fig. 7, lame mince n° 552 (6), collection j. von pia, naturhistorisches museum, wien (autriche) 1967 teutloporella hirsuta .pantiê, pl. ii, fig. 2-3.pepeljevaëke stene, tara mt, w serbie (yougoslavie): anisien 1973 non teutloporella hirsuta [= ? teutloporella peniculiformis].popa & dragastan, pl. iii, fig. 10-11; pl. xvi, fig. 63 pars teutloporella hirsuta var. obliqueforata pia 1935 1935a teutloporella hirsuta var. o b l i q u e f o r a t a n. var.pia, pl. iii, fig. 4.s mokranjska miljacka, e sarajevo (bosnie-herzégovine): anisien, hydaspien supérieur pelsonien inférieur.type: pl. iii, fig. 4, lame mince n° 570b (1), collection j. von pia, naturhistorisches museum, wien (autriche) teutloporella japonica endo 1956 1956 teutloporella japonica n. sp.endo, pl. 26, fig. 1-2.sakaishi, agano-mura, hannō-shi, iruma-gun, saitama-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie moyenne).syntypes: pl. 26, fig. 1-2, lame mince n° 333, department of earth sciences, saitama university, urawa (japon) 1961a teutloporella japonica .endo, pl. 3, fig. 8, extrait de endo (1956: pl. 26, fig. 1) 1963 teutloporella japonica .johnson, pl. 71, fig. 3 (non 5 ou 6), extrait de endo (1956: pl. 26, fig. 2); pl. 71, fig. 4 (non 5 ou 6), extrait de endo (1956: pl. 26, fig. 1) teutloporella ladinica dragastan in diaconu et dragastan 1969, nom. nud. 1969 (nom. nud.) teutloporella ladinica n. sp.dragastan in diaconu & dragastan, pl. iii, fig. 1-5.dealul glimeia, apuseni mts (roumanie): ladinien.“holotype” (syntypes): pl. iii, fig. 1, lame mince l.p.b. n° 9134; pl. iii, fig. 2, lame mince l.p.b. n° 9137; pl. iii, fig. 3, lame mince l.p.b. n° 9135; paratypes: pl. iii, fig. 4, lame mince l.p.b. n° 9131; pl. iii, fig. 5, lame mince l.p.b. n° 9138, col lection o. dragastan, laboratory of palaeontology, faculty of geology and geophysics, bucarest (roumanie) teutloporella maxima ott 1963, nom. nud. 1 9 6 3 (nom. nud.) teutloporella maxima n. sp.ott, fig. 14 pars & 26-29.schlauchkar, karwendelgebirge, tirol (autriche): ladinien (wettersteinkalk).“typus” (syntypes): lames minces n° a 1-3, collection e. ott, bayerische staatssammlung für paläontologie und historische geologie, münchen (allemagne) 1966 (nom. nud.) teutloporella maxima.ott, fig. 5 pars (1abc, 1ef, 3a & 4cde).schlauchkar, karwendelgebirge, tirol (autriche): ladinien (wettersteinkalk) 156 geologia croatica 53/1 teutloporella nodosa (schafhäutl 1863) pia 1920 [cf. diplopora nodosa schafhäutl 1863, emend. de castro 1979 ] teutloporella peniculiformis ott in granier et deloffre 1995, non 1963 1935 (?) bryozoe ?.ogilvie gordon, pl. v, fig. 4.w valle di cadore, véneto (italie): trias moyen (mendoladolomit) 1961 teutloporella sp. cf. t r i a s i n a .botteron, pl. vii, fig. 4.mont d’or, vaud (suisse): “virglorien” (anisien) supérieur 1963 (nom. nud.) teutloporella peniculiformis n. sp.ott, fig. 14 pars & 20-24.schlauchkar, karwendelgebirge, tirol (autriche): ladinien (wettersteinkalk).“typus” (syntypes): lames minces n° a 4-8, collection e. ott, bayerische staatssammlung für paläontologie und historische geologie, münchen (allemagne) 1964 bryozoa.bystrický, pl. xxxii, fig. 3.slovenský kras (slovaquie): anisien, pelsonien-illyrien 1965a (?) t e u t l o p o r e l l a sp.zanin buri, pl. 43, fig. 4.cugno di sotto, valle brembana, n bergamo, lombardia (italie): ladinien moyen-supérieur (esinokalk / fm del calcare di esino) 1 9 6 6 (nom. nud.) teutloporella peniculiformis.ott, fig. 3 gauche, extrait de ott (1963: fig. 23); fig. 3 droite, extrait de ott (1963: fig. 22); fig. 4 pars & 5 pars (2d, 5a & 5f).schlauchkar, karwendelgebirge, tirol (autriche): ladinien (wettersteinkalk) 1 9 7 1 (nom. nud.) teutloporella peniculiformis.zorn, pl. 4, fig. 4 pars.mte san salvatore, s lugano, ticino (suisse): ladinien (oberer salvatoredolomit) 1973 (?) teutloporella hirsuta .popa & dragastan, pl. iii, fig. 10-11.w lorǎu, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à dadocrinus communis); pl. xvi, fig. 63 pars.e lorǎu, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspienillyrien inférieur (couches à dadocrinus communis) 1974 “dasycladaceous limestones”.mello, pl. i, fig. 3 pars.s roæňava, slovenský kras (slovaquie): anisien, pelsonien-illyrien (steinalmkalk) 1 9 7 6 (nom. nud.) teutloporella peniculiformis.epting et al., fig. 6 pars.dosso dei morti, se adamello, nw valli giudicárie, trentino alto adige (italie): anisien moyen (dosso dei morti limestone / partie sommitale); fig. 8.d pars.mte spitz, s recoaro terme, w schio, véneto (italie): anisien-ladinien, illyrien supérieur fassanien (monte spitz limestone) 1 9 8 0 (nom. nud.) teutloporella peniculiformis.dragastan, pl. vii, fig. 7.glimeia, pǎdurea craiului, apuseni mts, bihor (roumanie): ladinien 1982 (nom. nud.) teutloporella peniculiformis.casati et al., pl. 35, fig. 1 pars, 2.d, 5 & 8.col vidàl, s auronzo di cadore, véneto (italie): anisien, pelsonien ? illyrien (fm del serla superiore) 1987 (?) dasycladacea.oravecz-scheffer, pl. xxv, fig. 3.forage szentantalfa 1 (szaf. 1), veszprém, balaton (hongrie): anisien, illyrien (tagyon limestone formation) 1 9 8 9 (nom. nud.) teutloporella peniculiformis.buëek, pl. i, fig. 2.se plavecké podhradie, malé karpaty (slovaquie): trias moyen, ? anisien inférieur (annabersky vápenec) 1 9 8 9 (nom. nud.) teutloporella peniculiformis.gaetani & gorza, pl. 10, fig. 5.crinale, lóvere, val camónica, ne bergamo, lombardia (italie): anisien (calcare di camorelli) 1 9 9 3 (nom. nud.) teutloporella peniculiformis.budai, lelkes & piros, pl. vi, fig. 1.forage drt. 1, dörgicse, veszprém, balaton (hongrie): anisien (tagyon limestone fm) 1993 (nom. nud.) teutloporella peniculiformis.senowbari-daryan et al., pl. 56, fig. 13.valdáora / olang, pusteria / pustertal, trentino alto adige (italie): anisien supérieur 1994 (nom. nud.) teutloporella peniculiformis.bucur et al., pl. 10, fig. 8-9; pl. 11, fig. 1.sasca zone, caraş-severin (roumanie): anisien, pelsonien-illyrien inférieur (sasca fm, valea susara limestone member) 1995 teutloporella peniculiformis.ott in granier & deloffre, p. 57, non figurée.typification et validation de l’espèce; “lectotype” (holotype): fig. 3 “linkes exemplar” in ott (1966) [= fig. 23 “linkes exem plar”in ott (1963) ], lame mince n° a 7, collection e. ott, bayerische staatssammlung für paläon tologie und historische geologie, münchen (allemagne) teutloporella scalata endo 1961 1961b teutloporella scalata n. sp.endo, pl. 17, fig. 2; pl. 19, fig. 4.w nagaoka, santō-machi, sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm); pl. 17, fig. 3.n manganji, santōm a c h i , 157granier & grgasoviê: les algues dasycladales du permien et du trias... sakata-gun, shiga-ken, honshū (japon): permien inférieur (samegai fm).holotype: pl. 19, fig. 4, lame mince n° 510605-2, geological survey of japan (japon) 1963 teutloporella scalata .johnson, pl. 71, fig. 7-8, extrait de endo (1961b: pl. 17, fig. 2-3) teutloporella tabulata pia 1935 1920 t e u t l o p o r e l l a n. sp. ind.pia, pl. ii, fig. 14.sw studenkoviêi, trebeviê, sarajevo (bosnie-herzégovine): anisien 1920 (?) t e u t l o p o r e l l a n. sp. ind.pia, pl. ii, fig. 15.sw studenkoviêi, trebeviê, sarajevo (bosnie-herzégovine): anisien 1935a teutloporella tabulata n. sp.pia, pl. ii, fig. 3.ograda, areæin brijeg grab, bosansko grahovo (bosnie-herzégovine): anisien; pia, pl. ii, fig. 4 & 7.n haliluêi, e sarajevo (bosnie-herzégovine): anisien, pelsonien; pl. ii, fig. 5.nw blizanac, trebeviê, s sarajevo (bosnie-herzégovine): anisien, pelsonien ? illyrien (bulogkalk); pl. ii, fig. 6.sarajevo (bosnie-herzégovine): anisien.types: pl. ii, fig. 3, lame mince n° 583a; pl. ii, fig. 4, lame mince n° 577a; pl. ii, fig. 5, lame mince n° 555d; pl. ii, fig. 6, lame mince n° 231; pl. ii, fig. 7, lame mince n° 576c, collection j. von pia, naturhistorisches museum, wien (autriche) 1964 teutloporella tabulata .bystrický, pl. i, fig. 1-7.pleπivecká planina, slovenský kras (slovaquie): anisien, pelsonien 1966 teutloporella tabulata .bystrický, pl. v, fig. 3.ponická lehôtka poniky oravce postredná môlëa, e banská bystrica (slovaquie): anisien, pelsonien (steinalmkalk) 1967 teutloporella tabulata .pantiê, pl. ii, fig. 4-5.pepeljevaëke stene, tara mt, w serbie (yougoslavie): anisien 1970 t e u t l o p o r e l l a t a b u l a t a .pantiê, pl. vii, fig. 1-2.ædrelo, e serbie (yougoslavie): anisien, pelsonien (“zone avec rhynchonella decurtata”) 1970 (?) t e u t l o p o r e l l a t a b u l a t a .pantiê, pl. vii, fig. 3-4.ædrelo, e serbie (yougoslavie): anisien, pelsonien (“zone avec rhynchonella decurtata”) 1972 (?) t e u t l o p o r e l l a cf. t a b u l a t a .bleahu et al., pl. v, fig. 2-3.vaşcǎu plateau, apuseni mts, bihor (roumanie): anisien moyen-supérieur 1972 (?) t e u t l o p o r e l l a cf. t a b u l a t a .»anoviê & kemenci, pl. i, fig. 6.forage golubinci-1 (gb-1), e ruma, vojvodina, serbie (yougoslavie): anisien (zone à rhynchonella decurtata) 1973 teutloporella tabulata .popa & dragastan, pl. xvi, fig. 61.e lorǎu, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspien-illyrien inférieur (couches à dadocrinus communis); pl. xvi, fig. 62 pars.w vǎii iadului, e pǎdurea craiului, apuseni mts, bihor (roumanie): anisien, hydaspienillyrien inférieur (couches à dadocrinus communis) 1975 t e u t l o p o r e l l a t a b u l a t a .pantiê-prodanoviê, pl. xxix, fig. 1 pars.pepeljevaëke stene, tara mt, w serbie (yougoslavie): anisien 1986 t e u t l o p o r e l l a t a b u l a t a .bystrický, pl. iii, fig. 10-11.pleπivecká planina, slovenský kras (slovaquie): anisien, pelsonien-illyrien inférieur (physoporella pauciforata oligoporella pilosa assemblage zone) 1988 teutloporella tabulata .pfeiffer, pl. 12, fig. 9.gartnerkofel, s hermagor, kärnten (autriche): anisien supérieur 1989 teutloporella tabulata .buëek, pl. i, fig. 5.n havranica, malé karpaty (slovaquie): anisien, pelsonien-illyrien inférieur (steinalmkalk) 1998 (?) teutloporella ? tabulata .petek (sokaë), pl. 1, fig. 6-8.carrière hrastenice, polhov gradec, w ljubljana (slovénie): anisien, illyrien supérieur teutloporella taishakuensis endo 1957 1957 teutloporella taishakuensis n. sp.endo, pl. 40, fig. 5-6.zenbutsuji-dani, taishaku-mura, hiba-gun, hiroshima-ken, honshū (japon): permien “inférieur” (yukisawa subsystem / partie supérieure).syntypes: pl. 40, fig. 5-6, lame mince n° 568, department of earth sciences, saitama university, urawa (japon) teutloporella ? tenuis pia 1912 1912 t e u t l o p o r e l l a ? t e n u i s n. sp.pia, pl. iii(ii), fig. 7-10.w lapëiêi, budva, monténégro (yougoslavie): trias moyen.types: pl. iii(ii), fig. 7, lame mince n° i/6; pl. iii(ii), fig. 8, lame mince n° i/10; pl. 158 geologia croatica 53/1 iii(ii), fig. 9-10, lame mince n° i/3, collection j. von pia, naturhistorisches museum, wien (autriche) 1912 oligoporella pilosa n. sp.pia, pl. iv(iii), fig. 5.w lapëiêi, budva, monténégro (yougoslavie): trias moyen.1 des 8 types: pl. iv(iii), fig. 5, lame mince n° i/3, collection j. von pia, naturhistorisches museum, wien (autriche) teutloporella terayamensis horiguchi 1958, nom. nud. 1 9 5 8 (nom. nud.) teutloporella terayamensis n. sp.horiguchi, pl. 28, fig. 4-5.taishaku-mura, hiba-gun, hiroshima-ken, honshū (japon): permien “inférieur” (myojinyama member kamikurawaza member).“syntypes”: pl. 28, fig. 4, lame mince no. 11068; pl. 28, fig. 5, lame mince no. 11067, department of earth sciences, saitama university, urawa (japon) teutloporella triasina (schauroth 1859) pia 1912 [cf. euteutloporella triasina (schauroth 1859) de castro 1993 ] teutloporella vicentina (tornquist 1899) pia 1912 [= diplopora vicentina tornquist 1899 ] teutloporella vicentina var. nana pia 1912 1912 teutloporella vicentina var. nana n. var.pia, pl. iii(ii), fig. 15-16.enna, w torrebelvicino, w schio, véneto (italie): trias moyen (monte spitz limestone).types: pl. iii(ii), fig. 15-16, lame mince n° xlv/3, collection j. von pia, naturhistorisches museum, wien (autriche) teutloporella vicentina var. vicentina pia 1912 [par accident ! ] 1899 diplopora vicentina n. sp.tornquist, pl. xviii, fig. 6 & 6.a-b.pollichero, fongara, mte spitz, s recoaro terme, w schio, véneto (italie): trias moyen (monte spitz limestone).types: pl. xviii, fig. 6 & 6.a-b 1912 teutloporella vicentina n. comb.pia, pl. iii(ii), fig. 11-14.tretto, n schio, véneto (italie): trias moyen (monte spitz limestone) 1920 teutloporella vicentina.pia, pl. ii, fig. 9-10.velika strana, velebit mt (croatie): ladinien 1950 non teutloporella vicentina [= diplopora annulata ].herak, pl. i, fig. 1 1955 teutloporella vicentina.accordi, fig. 17.col del bous, marmolada, trentino alto adige-véneto (italie): ladinien-carnien (calcare della marmolada) 1967 teutloporella vicentina.leonardi, fig. 124, extrait de accordi (1955: fig. 17) 1976 teutloporella vicentina.epting et al., fig. 8.b.mte spitz, s recoaro terme, w schio, véneto (italie): anisien-ladinien, illyrien supérieur fassanien (monte spitz limestone) 1987 teutloporella vicentina.braga & martin, pl. i, fig. 2.sierra de baza, gor baza, granada (espagne): anisien-ladinien 1990 teutloporella vicentina .scheuber, pl. 9, fig. 2 pars.mte rove, recoaro terme, w schio, véneto (italie): anisien-ladinien, illyrien-fassanien moyen (monte spitz limestone); pl. 11, fig. 4.mte spitz, s recoaro terme, w schio, véneto (italie): anisien-ladinien, illyrien-fassanien moyen (monte spitz limestone) thailandoporella endo 1969 [synonyme postérieur de gyroporella gümbel 1872, emend. benecke 1876, d’après bassoullet et al., 1979 ] thailandoporella elegans endo 1969 1969 thailandoporella elegans n. sp.endo, pl. xxv, fig. 1 & 4-6.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancelli 159granier & grgasoviê: les algues dasycladales du permien et du trias... n a zone à neoschwagerina simplex / partie inférieure).holotype: pl. xxv, fig. 1, lame mince n° gk.d 13084, kyūshū university, fukuoka (japon) 1992 (?) likanella (?) cf. elegans [s i c].vachard et al., pl. iii, fig. 3 pars.s doi luang mts, nw thaïlande (thaïlande): bolorien *thailandoporella phlongphrabensis endo 1969 1969 thailandoporella phlongphrabensis n. gen. n. sp.endo, pl. xxii, fig. 8-9; pl. xxv, fig. 2-3.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina zone à neoschwagerina simplex / partie inférieure).holotype: pl. xxii, fig. 8, lame mince n° gk.d 13055, kyūshū university, fukuoka (japon) triploporella steinmann 1880, emend. barattolo 1981 triploporella subg. sinoporella yabe 1949 *triploporella (sinoporella ) leei yabe 1949 1949 triploporella (s i n o p o r e l l a) l e e i n. subgen. n. sp.yabe, fig. 1-2.tiaoyütai, chao-hsien, anhui (chine populaire): permien “inférieur” (chihsia limestone).types: fig. 1-2, collection h. yabe (h. huzimoto), tokyo ? (japon) 1974 sinoporella leei.mu, pl. 167, fig. 3.sw chine (chine populaire) uragiella pia 1924 uragiella supratriasica bystrický 1967 1967b uragiella supratriasica n. sp.bystrický, pl. xii, fig. 1-3; pl. xiii, fig. 1-4; pl. xiv, fig. 1-4.w silická brezová, slovenský kras (slovaquie): carnien inférieur.holotype: pl. xii, fig. 1, lame mince n° 2805, collection j. bystricky´, geological institute, slovak academy of sciences, bratislava (slovaquie) 1979 uragiella supratriasica .bystrický, pl. ii, fig. 5.colline kopa, n stratená, n dobπiná, stratenská hornatina mts (slovaquie): carnien supérieur (tisoveckalk) 1986 uragiella supratriasica .bystrický, pl. v, fig. 6.silická brezová, slovenský kras (slovaquie): carnien, julien-tuvalien (andrusoporella duplicata taxon-range zone) uragiellopsis vachard 1980 *uragiellopsis breziki milanovi∆ ex vachard 1980 [= salopekiella breziki milanovi∆ 1975, nom. nud. ] 1 9 7 5 (nom. nud.) salopekiella (?) b r e z i k i n. sp.milanoviê, pl. i, fig. 1-4; pl. ii, fig. 1-6; pl. iii, fig. 1-4.brezik, sw medak, se gospiê, velebit mt (croatie): artinskien supérieur kazanien inférieur.holotype: pl. i, fig. 2, lame mince n° u 4012/1, collection m. milanoviê, institut za geoloπka istraæivanja [insti tute of geology ], zagreb (croatie) 1980 uragiellopsis breziki n. gen. n. comb.vachard, pl. 23, fig. 5.sultali, tezak (afghanistan): murghabien supérieur.validation de l’espèce 1981 uragiellopsis breziki n. gen. n. comb.vachard in vachard & montenat, pl. 4, fig. 8, extrait de vachard (1980: pl. 23, fig. 5) uragiellopsis sola (endo 1969) vachard 1980 [= oligoporella sola endo 1969, non 1968 ] 1968b (nom. nud.) oligoporella sola n. sp.endo, “chart”, non figurée.type non figuré 1969 oligoporella sola n. sp.endo, pl. xxvii, fig. 5-6.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina ).holo type: pl. xxvii, fig. 5, lame mince n° gk.d 13287, kyūshū university, fukuoka (japon) 160 geologia croatica 53/1 1969 non oligoporella sola n. sp.endo, pl. xxvii, fig. 7.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien moyen (rat buri limestone, zone à cancellina ) 1980 uragiellopsis sola n. comb.vachard, p. 354-355, non figurée 1992 uragiellopsis sola .vachard et al., pl. iii, fig. 10 pars.n ban na wai, nw thaïlande (thaïlande): murghabien supérieur midien uraloporella kordé 1950 *uraloporella variabilis kordé 1950, emend. mamet et villa 1995 1950 uraloporella variabilis n. gen. n. sp.kordé, fig. 4.bouzgala river, n oural (fédération de russie): carbonifère “moyen”.type: fig. 4, lame mince n° 41, collection v.a. varsanofiev, p.i.n. (fédéra tion de russie) 1956 (nom. nud.) samarella setosa n. gen. n. sp.maslov & kulik, p. 129, non figurée.type non figurée 1961a uraloporella variabilis .endo, pl. 1, fig. 9, extrait de kordé (1950: fig. 4) 1963 uraloporella variabilis .maslov in bakhrameeba et al., pl. xvii, fig. 7.(fédération de russie): carbonifère 1964 samarella setosa .kulik, pl. viii, fig. 9.yulovo-ishima (fédération de russie): carbonifère, silésien, moscovien, podolskien.validation de l’espèce et du genre; holotype: pl. viii, fig. 9, lame mince n° 3438/12 1964 (nom. nud.) uraloporella sieswerdai n. sp.rácz, pl. iv, fig. 8; pl. v, fig. 1-3.león (espagne): carbonifère, silésien, moscovien (fm lois-ciguera, zone à fusulinella , sous-zone a).holotype: pl. v, fig. 1, lame mince n° “iii-iv-s-79” ou “iiii-v-s-79”, dept. stratigr. & paleont., leiden university (pays-bas) 1 9 6 5 (?) (nom. nud.) samarella massieuxae n. sp.güvenç, pl. a10, fig. 9-10.karapertarlar, vallée du dikenli dere, alanya (turquie): carbonifère, silésien, moscovien supérieur.syntypes: pl. a10, fig. 9-10, lame mince t.g. p-8-k-2711, collection t. güvenç, laboratoire de micropaléontologie, faculté des sci ences de paris (france) 1966a (?) (nom. nud.) samarella massieuxae n. sp.güvenç, pl. xxxii, fig. 6-7.karapertarlar, vallée du dikenli dere, alanya (turquie): carbonifère, silésien, moscovien supérieur; pl. xxxii, fig. 8, extrait de güvenç (1965: pl. a10, fig. 9).syntypes: pl. xxxii, fig. 6-8, lame mince p. 8-k 2711, collection t. güvenç, laboratoire de micropaléontologie, faculté des sciences de paris (france) 1974 uraloporella variabilis .riding & jansa, pl. 2, fig. 1-4.oural (fédération de russie): carbonifère “moyen” 1974 non uraloporella variabilis [= jansaella ridingi ; = ? issinella devonica].riding & jansa, pl. 1, fig. 1-6.forage sobc snipe lake, w central alberta (canada): dévonien, ? givétien (swan hills fm) 1975b uraloporella sp.mamet & roux, fig. 4-6.w glacier de wood, ellesmere, nunavut (canada): carbonifère, silésien, moscovien (fm otto fiord) 1975b uraloporella variabilis .mamet & roux, fig. 1, extrait de kordé (1950: fig. 4) 1976 non uraloporella variabilis [= jansaella ridingi ].faber & riding, fig. 4-5.carrière wotam, üxheim, eifel, rheinland-pfalz (allemagne): dévonien, givétien inférieur (loogh fm, “eowotanium” member) 1976 non uraloporella variabilis [= jansaella ridingi ].riding & jansa, fig. 1.menyous gap, fitzroy crossing, canning basin (australie): givétien-frasnien (pillara fm, menyous member) 1979a uraloporella variabilis .roux, pl. 14, fig. 1-2, 7, 9 & 12-13.girty creek, ellesmere, nunavut (canada): carbonifère, silésien, moscovien moyen ou plus jeune (fm nansen); pl. 14, fig. 3-6 & 10-11.glacier de wood, ellesmere, nunavut (canada): carbonifère, silésien, moscovien moyen ou plus jeune (fm otto fiord); pl. 14, fig. 8 & 14.blind fiord, ellesmere, nunavut (canada): assélien supérieur ou sakmarien inférieur (fm belcher channel) 1979 samarella setosa .zagorodnjuk, pl. ii, fig. 6.bashkirskaya (fédération de russie): carbonifère, silésien, moscovien 1981 uraloporella variabilis .rauzer-chernousova & korolyuk, pl. iii, fig. 4-5.s oural (fédération de russie): carbonifère, silésien, moscovien supérieur 1982 non uraloporella variabilis .wright, fig. 1-2.s wales (royaume-uni): carbonifère, dinantien, viséen, ? arundien (llanelly fm) 161granier & grgasoviê: les algues dasycladales du permien et du trias... 1984 uraloporella rara n. sp.saltovskaja, pl. xii, fig. 1.a & 1-10; pl. xiii, fig. 1-9.(tadjiskistan): carbonifère, silésien, moscovien.holotype: pl. xii, fig. 1-1.a, lame mince n° 18428/1, novosibirsk (fédération de russie) 1985 uraloporella variabilis .roux, pl. 3, fig. 11, extrait de mamet & roux (1975b: fig. 6) 1987 uraloporella variabilis .mamet et al., pl. 14, fig. 1-14, extrait de roux (1979a: pl. 14, fig. 1-14) 1988 uraloporella .deloffre, pl. 1, fig. 9, extrait de roux (1985: pl. 3, fig. 11) 1995 uraloporella variabilis emend.mamet & villa, pl. i, fig. 1-9.la huelga, llanes, e ribadesella, asturias (espagne): carbonifère, silésien, moscovien, podolskien (cuera limestones) vaginopora defrance in bronn 1825 [synonyme postérieur de neomeris lamouroux 1816, emend. deloffre 1970 ] vaginopora ? pustulosa schafhäutl 1863 1863 vaginopora pustulosa n. sp.schafhäutl, pl. lxv.e, fig. 21.a-b.wettersteinwand, bayern (allemagne) .types: pl. lxv.e, fig. 21.a-b, coll. schafhäutl velebitella kochansky-devidé 1964 velebitella similis endo 1968 1968b velebitella similis n. sp.endo, pl. i, fig. 1.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien inférieur (zone à m i s e l l i n a).type: pl. i, fig. 1, lame mince n° 13905, departement of geology, kyūshū university, fukuoka (japon) 1969 velebitella similis.endo, pl. xl, fig. 6.khao phlong phrab, e phra phutthabat, n sara buri, n krung thep / bangkok (thaïlande): permien inférieur (rat buri limestone, zone à misellina) velebitella simplex kochansky-devidé 1964 [cf. pseudovelebitella simplex (kochansky-devidé 1964) mamet et roux 1978 ] *velebitella triplicata kochansky-devidé 1964 1964a velebitella triplicata n. gen. n. sp.kochansky-devidé, pl. iii, fig. 1.velebit mt (croatie): permien “moyen”; pl. iii, fig. 2-6; pl. iv, fig. 1, 2 pars & 3-4.egeljac ©iloviê, velebit mt (croatie): permien “ s u p é r i e u r ”.holotype: pl. iii, fig. 3, lame mince n° 2209, collection v. kochansky-devidé, geoloπko-paleontoloπki zavod, prirodoslovno-matematiëki fakultet [geological and palaeontological institute, faculty of sciences ], zagreb (croatie) 1964b velebitella triplicata .kochansky-devidé, pl. 19, fig. 2, extrait de kochansky-devidé (1964a: pl. iv, fig. 3); pl. 19, fig. 3-4, extrait de kochansky-devidé (1964a: pl. iii, fig. 2-3) 1965 velebitella triplicata .güvenç, pl. m14, fig. 1.a; pl. a9, fig. 1 pars.w taurus (turquie): permien “supérieur” 1976 (?) velebitella cf. t r i p l i c a t a .vachard in montenat et al., pl. xix, fig. 6.djebel akhdar, oman mts (oman): murghabien moyen-supérieur 1985 velebitella triplicata .vachard, pl. 2, fig. 8 & 10.djebel tebaga (tunisie): murghabien supérieur; pl. 2, fig. 9.djebel tebaga (tunisie): murghabien supérieur 1988 velebitella triplicata .buser et al., pl. 1, fig. 4; pl. 4, fig. 1 pars.medvodje, ne træië (slovénie): permien “supérieur” (karavanke fm, uppermost member) 1991 velebitella triplicata .sremac, pl. 2, fig. 4.bruπane, baπke oπtarije, velebit mt (croatie): murghabien (zone à neoschwagerina craticulifera ) 1992 velebitella triplicata .vachard et al., pl. iii, fig. 9 pars.n ban na wai, nw thaïlande (thaïlande): murghabien supérieur midien 1992 (?) velebitella cf. triplicata .vachard et al., pl. iii, fig. 10 pars.n ban na wai, nw thaïlande (thaïlande): murghabien supérieur midien 162 geologia croatica 53/1 1995 velebitella triplicata .vachard et al., pl. 55, fig. 1-2.ídhra / hydra (grèce): murghabien moyensupérieur velomorpha horiguchi 1961, nom. nud. [“synonyme” de anthracoporella pia 1920, d’après bassoullet et al., 1979 ] *velomorpha kuzuensis horiguchi 1961, nom. nud. 1959 anthracoporella spectabilis .konishi, pl. xxxi, fig. 14-23.kuzu, aso-gun, tochigi-ken, honshū (japon): permien inférieur-moyen (zone à pseudofusulina zone à parafusulina ) 1961 (nom. nud.) velomorpha kuzuensis n. gen. n. sp.horiguchi, pl. 23, fig. 1-7; pl. 25.yamasuge, kuzu, asogun, tochigi-ken, honshū (japon): permien “moyen”.“holotype” (syntypes): pl. 25, reg. no. 11134, collection m. horiguchi, department of earth sciences, saitama university, urawa (japon) velomorpha valiabilis horiguchi 1961, nom. nud. 1 9 6 1 (nom. nud.) velomorpha valiabilis n. sp.horiguchi, pl. 24, fig. 1-4.yamasaki, maiya-machi, tome-gun, miyagi-ken, honshū (japon): permien “supérieur”.“holotype” (syntypes): pl. 24, fig. 3-4, reg. no. 11141, collection m. horiguchi, department of earth sciences, saitama university, urawa (japon) 1963 (nom. nud.) velomorpha valiabilis.johnson, pl. 72, fig. 1-4, extrait de horiguchi (1961: pl. 24, fig. 1-4) fig. 26 velebitella triplicata (kochansky-devidé, 1964a, pl. iii, fig. 6), x55. fig. 27 velebitella triplicata (kochansky-devidé, 1964a, pl. iii, fig. 3), x44. 163granier & grgasoviê: les algues dasycladales du permien et du trias... vermiporella stolley 1893 vermiporella ? nipponica endo in endo et kanuma 1954 [forme proche, si ce n’est synonyme, de pseudovermiporella sodalica elliott 1958, espèce exclue des dasycladales ] vermiporella serbica pia 1937, nom. nud. [cf. vermiporella serbica pia ex kochansky et herak 1960, nom. nud. ] vermiporella serbica pia ex kochansky et herak 1960, nom. nud. [forme proche, si ce n’est “synonyme”, de pseudovermiporella sodalica elliott 1958, espèce exclue des dasycladales ] vermiporella ? sumatrana pia 1935 [forme proche, si ce n’est synonyme, de pseudovermiporella sodalica elliott 1958, espèce exclue des dasycladales ] vermiporella velebitana (schubert 1909) pia 1920 [= stolleyella velebitana schubert 1909 ] 1909 stolleyella velebitana n. sp.schubert, pl. xvi, fig. 8 pars, 10 pars & 12 (à gauche).paklenica, velebit mt (croatie): “carbonifère supérieur”.types: pl. xvi, fig. 8 pars, 10 pars & 12 (à gauche) 1915 (?) vermiporella cf. velebitana.négris (pia), fig. 8 pars.gourissi, parnassós mts (grèce): “carbonifère” 1919 non vermiporella cf. velebitana [= mizzia velebitana].négris, pl. xxvi, fig. 1 1919 non vermiporella cf. velebitana.négris, pl. xxvi, fig. 2.gourissi, parnassós mts (grèce): “carbonifère” 1919 non stolleyla velebitana [sic; = anthracoporella spectabilis ].négris, pl. xxvi, fig. 3-4 1920 vermiporella velebitana n. comb.pia, pl. i, fig. 1-3.paklenica, velebit mt (croatie): “carbonifère supérieur” 1927 (?) vermiporella velebitana.ogilvie gordon, pl. xiii, fig. 6 pars.plesch d’inaz, val gardena / grödnertal, trentino alto adige (italie): permien supérieur (bellerophon fm) xainzanella mu 1984 *xainzanella sinensis mu 1984 1984 xainzanella sinensis n. gen. n. sp.mu, pl. i, fig. 1, 1.a & 2.xiala mt, ne xainza, xizang / tibet (chine populaire): guadalupien (xiala fm) .holotype: pl. i, fig. 2, lame mince n° pb 11354, nanjing institute of geology and paleontology, academia sinica, nanjing (chine populaire) zaporella rácz 1964, non 1966 zaporella baxoensis mu 1982 1982 zaporella baxoensis n. sp.mu, pl. ix, fig. 1-5.xizang / tibet (chine populaire): permien “inférieur” / partie supérieure.holotype: pl. ix, fig. 1, lame mince n° pb8065, nanjing institute of geology and paleontology, academia sinica, nanjing (chine populaire) 164 geologia croatica 53/1 3. bibliographie abate, b., catalano, r., d’argenio, b., di stefano, p. & riccobono, r. (1977): 3 3 . relationships of algae with depositional environments and faunal assemblages of the panormide carbonate platform, upper triassic, northwestern sicily.in: flügel, e. (ed.): fossil algae. recent results and developments. springer-verlag, berlin, p. 301-313, 4 pl. (1-4). abate, b., catalano, r., d’argenio, b., di stefano, p., lo cicero, g., montanari, l., pecoraro, c. & renda, p. (1982): evoluzione delle zone di cerniera tra piattaforme carbonatiche e bacini nel mesozoico e nel paleogene della sicilia occidentale.in: catalano, r. & d ’ a r g e n i o , b. (eds.): guida alla geologia della sicilia occidentale. società geologica italiana, guide geologiche regionali, palermo, p. 53-81. accordi, b. (1955): guida delle excursioni.lviii riunione estiva della società geologica italiana, ferrara dolomiti occidentali. pubblicazioni dell’ istituto di geologia e mineralogia dell’universita di ferrara, vol. iv, n° 19, 58 p. accordi, b. (1956): calcareous algae from the upper permian of the dolomites (italy) with stratigraphy of the “b e l l e r o p h o n-zone”.journal of the palaeontological society of india, lucknow, vol. 1, inaugural number, p. 75-84, 7 pl. h.-t. (6-12). accordi, b. & broglio loriga, c. ( 1 9 6 7 ) : capitolo vii. formazione a bellerophon (permiano superiore).in: leonardi, p. (ed.): le dolomiti. geologia dei monti tra isarco e piave. consiglio nazionale delle ricerche e della giunta provinciale di trento, vol. 1, p. 85-106, 5 pl. (xiii-xvii). a h l b u r g, j. (1906): die trias im südlichen oberschlesien.königlich preußischen geologischen landesanstalt und bergakademie, abhandlungen, berlin, heft 50, p. 1-163, 6 pl. h.-t. (i-vi). alth, a. v o n (1878): o galicyjskich gatunkach skam i e n i aĺych otwornic rodzaju g y r o p o r e l l a g ü m b . rozprawy i sprawozdania z posiedzen wydzialu matematyczno-przyrodniczego, iii akademii umiejetnosci w krakowie, t. v, p. 71-112, 2 pl. h.-t. (vivii). an–elkovi∆, m. (1978): stratigrafija jugoslavije. paleozoik i mezozoik.minerva, subotica-beograd, 1016 p. 148 pl. (i-cxlviii). andrusov, d. (1937): sur quelques fossiles triasiques des carpathes occidentales.věstník královské ëeské spoleënosti nauk, třída matemat.přírodověd, praha, roëník 1937, 20 p., 1 pl. h.-t. (i). andrusov, d. (1959): geológia ëeskoslosvenský c h karpát.vydavatel’stvo slovenskej akadémie vied, bratislava, zväzok ii, 349 p., 84 pl. (i-lxxiv). andrusov, d. (1965): geologie der tschechoslowakischen karpaten ii.akademie-verlag, berlin, 443 p. anonyme (1959): microfacies italiane (dal carbonifero al miocene medio).agip mineraria, milano, 35 p., 155 pl. h.-t. (i-cxlv). archiac, e.j. d’ (1843): description géologique du département de l’aisne.mémoires de la société géologique de france, paris, 1ère série, t. v, n° 3, p. 129-418, 8 pl. (xxiv-xxxi). arthaber, g. v o n (1908): die alpine trias des mediterran-gebietes.in: frech, f. (ed.): lethaea geognostica. handbuch der erdgeschichte. teil ii. das mesozoicum. band 1. trias (1903-1908). e. schweizerbart’sche verlag, stuttgart, p. 223-472, 17 pl. h.-t. (34-50). assereto, r., casati, p. & zanin buri, c. (1965): il trias in lombardia (studi geologici e paleontologici). xiv. sulla presenza di una scogliera anisica nella bassa val camonica.rivista italiana di paleontologia e stratigrafia, milano, vol. 71, n° 3, p. 805-837, 5 pl. (77-81). assereto, r. & monod, o. (1974): les formations triassiques du taurus occidental à seydischir (turquie méridionale). stratigraphie et interprétation sédimentologique.memorie rivista italiana di paleontologia e stratigrafia, milano, vol. xiv, p. 159-191. assmann, p. (1926): die fauna der wirbellosen und die diploporen der oberschlesischen trias mit ausnahme der brachiopoden, lamellibranchiaten, gastropoden und korallen.jahrbuch der preußischen geologischen landesanstalt, berlin, band xlvi (1925), p. 504-527, 2 pl. h.-t. (8-9). baltres, a. (1975): excursion g. der obere anis vom lacul roşu (ostkarpaten): algen, foraminiferen, sedimentologie und diagenese.14th european micropaleontological colloquium, micropaleontological guide to the mesozoic and tertiary of the romanian carpathians. institute of geology and geophysics, bucharest, p. 115-121, 2 pl. h.-t. (i-ii). barattolo, f. (1981): osservazioni su triploporel la fraasi s t e i n m a n n 1880 (alghe verdi, dasicladali).atti dell’accademia pontaniana, napoli, nuova serie, vol. xxx, p. 1-42, 16 pl. h.-t. (i-xvi). barattolo, f. (1991): chapter 22. mesozoic and cenozoic marine benthic calcareous algae with particular regard to mesozoic dasycladaleans.in: r i d i n g, r. (ed.): calcareous algae and stromatolites. springer-verlag, berlin, p. 504-540, 7 pl. (ivii). barattolo, f. & de castro, p. (1991): site 10 middle triassic of marsico nuovo.in: b a r a ttolo, f., de castro, p. & parente, m. 165granier & grgasoviê: les algues dasycladales du permien et du trias... (eds.): field trip guide-book, 5th international symposium on fossil algae (capri, 7-12 avril 1991), p. 103-105, 1 pl. (xiv). barattolo, f., de castro, p. & parente, m. (1991): 6. some remarks on griphoporella curvata (g u e m b e l 1872) p i a 1915, dasicladacean green alga from the upper triassic.in: 5th international symposium on fossil algae (capri, 7-12 avril 1991), abstracts. barattolo, f., de castro, p. & parente, m. (1993): some remarks on griphoporella curvata (g ü m b e l 1872) p i a 1915, dasycladacean green alga from the upper triassic.in: b a r a t t o l o , f., de castro, p. & parente, m. (eds.): studies on fossil benthic algae. bollettino della società paleontologica italiana, modena, special volume n° 1, p. 23-45, 7 pl. (1-7). barattolo, f. & parente, m. (1991): site 8 late triassic of buonabitacolo (salerno, campania).in: barattolo, f., de castro, p. & parente, m. (eds.): field trip guide-book, 5th international symposium on fossil algae (capri, 712 avril 1991), p. 85-90, 2 pl. (ix-x). baretti, a. (1919): contributo allo studio delle siphoneae verticillateae del calcare di villanovamondovi.atti della società italiana di scienze naturali e del museo civico di storia naturale in milano, vol. lviii, p. 216-236. bassoullet, j.-p., bernier, p., conrad, m.a., deloffre, r. & jaffrezo, m. (1978): l e s algues dasycladales du jurassique et du crétacé.géobios, lyon, mémoire spécial 2, 330 p., 40 pl. h.t. (1-40). bassoullet, j.-p., bernier, p., deloffre, r., g é n o t, p., jaffrezo, m. & vachard, d. (1979): essai de classification des dasycladales en tribus.in: 2è m e symposium international sur les algues fossiles (paris, 23-26 avril 1979). bulletin des centres de recherches exploration-production elf-aquitaine, pau, vol. 3, n° 2, p. 429-442. bebout, d.g. & coogan, a.h. (1964): algal genus a n t h r a c o p o r e l l a pia.journal of paleontology, tulsa, vol. 38, n° 6, p. 1093-1096, 1 pl. h.-t. (169). benecke, e.w. (1876): ueber einige versteinerungen, insbesondere aus den umgebungen von esino.in: über die umgebungen von esino in der lombardei. geognostisch-paläontologische beiträge, münchen, band ii, heft iii, p. 296-317, 4 pl. h.-t. (xxi-xxiv [1-4]). benecke, e.w. (1898): d i p l o p o r a und einige andere versteinerungen im elsass-lothringischen muschelkalk.mittheilungen der geologischen landesanstalt von elsass-lothringen, strassburg, band iv, p. 277285. bérczi-makk, a., haas, j., rálisch-felgenhauer, e. & oravecz-scheffer, a. (1993): upper paleozoic-mesozoic formations of the midtransdanubian unit and their relationships.acta geologica hungarica, budapest, vol. 36/3, p. 263296, 12 pl. (i-xii). bérczi-makk, a. & kochansky-devidé, v. (1981): marine lower and middle permian in the oil exploratory well újfalu-i (sw-hungary).acta geologica academiae scientiarum hungaricae, budapest, vol. 24 (1), p. 117-128, 5 pl. h.-t. (i-v). berger, s. & kaever, m.j. (1992): d a s y c l a d a l e s . an illustrated monograph of a fascinating algal order.thieme, stuttgart, 247 p. bernecker, m. (1996): upper triassic reefs of the oman mountains: data from the south tethyan margin.facies, erlangen, 34, p. 41-74, 8 pl. (1118). bernecker, m., weidlich, o. & flügel, e. (1999): response of triassic reef coral communities to sea-level fluctuations, storms and sedimentation: evidence from a spectacular outcrop (adnet, austria).facies, erlangen, 40, p. 229-279, 17 pl. (3046). bernier, p. (1979): le genre petrascula g ü m b e l 1873, algue dasycladacée: emendation, révision des espèces du genre, création de nouvelles espèces.géobios, lyon, n° 12, fasc. 6, p. 839-861, 5 pl. (1-5). bilgütay, u. (1959): the permian calcareous algae from southeastern anatolia.bulletin of the mineral research and exploration institute of turkey, ankara, n° 52 (foreign ed.), p. 48-58, 4 pl. h.-t. (i-iv). bilgütay, u. (1960): some permian calcareous algae from the vicinity of ankara.bulletin of the mineral research and exploration institute of turkey, ankara, n° 54 (foreign ed.), p. 52-65, 5 pl. h.-t. (i-v). bilgütay, u. (1968): some triassic calcareous algae from plackles (hohe wand, lower austria).verhandlungen der geologischen bundesanstalt, wien, jahrgang 1968, hefte 1-3, p. 65-79, 3 pl. h.-t. (i-iii). bleahu, m., tomescu, c. & panin, ş. (1972): c o n t r i b uţii la biostratigrafia depozitelor triasice din platoul vaş cǎu (munţ ii apuseni) [contribution à la biostratigraphie des dépôts triasiques du plateau de v aş cǎu (monts apuseni)].dǎri de seamǎ a l e ş e d i nţ elor, bucureşti, vol. lviii (1971), 3. paleontologie, p. 5-25, 11 pl. h.-t. (i-xi). bloch, j.-p. & lefevre, r. (1969): présence de diplopora annulata dans le ladinien de la zone briançonnaise des alpes cottiennes méridionales (alpes occidentales franco-italiennes).compte rendu 166 geologia croatica 53/1 de l’académie des sciences, paris, série d, t. 269, p. 1166-1168, 1 pl. h.-t. (i). bogush, o.i. & juferev, o.v. (1976): opisanie fauny. tip protozoa.in: pribalkhash’e perekhodnaja zona biogeograficheskikh pojasov pozdnego k a r b o n a . akademija nauk sssr, sibirskoe otdelenie, institut geologii i geofiziki, trudy, moskva, vyp. 285, p. 52-57 & 105-111, 6 pl. h.-t. (i-vi). boni, m., iannace, a., torre, m. & zamparelli, v. (1994): the ladinian-carnian reef facies of monte caramolo (calabria, southern italy).facies, erlangen, 30, p. 101-118, 6 pl. (15-20). borza, k. (1975): mikroproblematika aus der oberen trias der westkarpaten.geologický zborník geologica carpathica, bratislava, vol. 26, n° 2, p. 199-236, 8 pl. (i-viii). botteron, g. (1961): étude géologique de la région du mont d’or (préalpes romandes).eclogae geologicae helvetiae, basel, vol. 54, n° 1, p. 29-106, 12 pl. h.-t. (i-xii). bousquet, j.-c., megard-galli, j. & zorn, h . (1978): quelques éléments de datation du trias moyen et supérieur de l’apennin calabro-lucanien (italie méridionale).geologica romana, roma, vol. xvii, p. 71-83, 3 pl. (i-iii). bradner, r. & resch, w. (1981): reef development in the middle triassic (ladinian and cordevolian) of the northern limestone alps near innsbruck, austria.in: toomey, d.f. (ed.): european fossil reef models. sepm special publication, tulsa, n° 30, p. 203-231. braga, j.c. (1986): upper triassic dasycladaceans in the sierra de baza (alpujárride complex, betic cordillera, se spain).neues jahrbuch für geologie und paläontologie, monatshefte, stuttgart, jahrgang 1986, heft 4, p. 239-247. braga, j.c. & martín, j.m. (1987): distribución de las algas dasycladáceas en el trías alpujárride.cuadernos de geología ibérica, madrid, vol. 11, p. 475-489, 1 pl. (i). broglio loriga, c., neri, c., pasini m. & posenato, r. (1988): marine fossil assemblages from upper permian to lowermost triassic in the western dolomites (italy).in: cassinis, g. (ed.): permian and triassic boundary in the south alpine segment of the western tethys, and additional regional reports. memorie della società geologica italiana, roma, vol. xxxiv (1986), p. 5-44, 8 pl. (1-8). brönnimann, p., whittaker, j.e. & zaninetti, l. (1978): s h a n i t a, a new pillared miliolacean foraminifer from the late permian of burma and thailand.rivista italiana di paleontologia e stratigrafia, milano, vol. 84, n° 1, p. 63-92, 6 pl. (7-12). bronn, h.g. (1825): system der urnveltlichen pflanzenthiere.heidelberg, 1 vol.-text., 7 pl. bubnoff, s. v o n (1921): die ladinische fauna von forno (mezzovalle) bei predazzo.verhandlungen naturhistorisch-medizinischen vereins zu heidelberg, neue folge, band xiv, p. 257-636, 3 pl. h.-t. (x-xii). bu»ek, s. (1989): výsledky výskumu dasykladálnych rias v triasových sekvenciách malých karpát.zbornik z paleontologickej konferencie, geologic ký ústav dionýza ©túra, bratislava, p. 133-137, 3 pl. h.-t. (i-iii). bucur, i.i. (1991, inédit): studiul jurasicului si cretacicului din unele perimetre de perspectiva pentru carbunii liasici, intre valea minisului si valea nerei (compartmentul central al zonei resita, banat).t e zǎ de doctorat, universitatea “babeş b a l y a i ” , cluj-napoca, 203 p., atlas 100 pl. h.-t. (1-100). bucur, i.i. (1997): révision de la variété p i l o s a p i a e x b y s t r i c ký, 1964, de l’espèce o l i g o p o r e l l a p i l o s a pia, 1912, une algue dasycladacée de l’anisien.revue de paléobiologie, genève, vol. 16, n° 1, p. 181-186, 1 pl. (i). bucur, i.i. (1999): stratigraphic significance of some skeletal algae (dasycladales, caulerpales) of the phanerozoic.in: farinacci, a. & lord, a.r. (eds.): depositional episodes and bioevents. palaeopelagos, special publication no 2, roma, p. 53104. bucur, i.i., strutinski, c. & pop-stratila, d . (1994): middle triassic carbonate deposits and calcareous algae from the sasca zone (southern carpathians, romania).facies, erlangen, 30, p. 85100, 6 pl. (9-14). budai, t., lelkes, g. & piros, o. (1993): e v o l ution of middle triassic shallow marine carbonates in the balaton highland (hungary).acta geologica hungarica, budapest, vol. 36/1, p. 145-165, 6 pl. (i-vi). büchner, k.-h. (1970, i n é d i t): geologie der nördlichen und südwestlichen gesäuse-berge (ober-steiermark, österreich).inaugural-dissertation, philipps-universität, marburg, 118 p. buggisch, w. & n o é , s. (1988): upper permian and permian-triassic boundary of the carnia (bellerophon formation, tesero horizon, northern italy).in: cassinis, g. (ed.): permian and triassic boundary in the south alpine segment of the western tethys, and additional regional reports. memorie della società geologica italiana, roma, vol. xxxiv (1986), p. 91-106, 2 pl. (1-2). bukovac, j. & s o k a » , b. (1989): o gornjotrijaskim i donjolijaskim vapnencima sjeverne padine gorjanaca, juæno od kostanjevice (ji slovenija) i njihovom znaëenju za tumaëenje geotektonskih odnosa u πirem prostoru [upper triassic l o w e r liassic limestones on the northern slopes of mt. 167granier & grgasoviê: les algues dasycladales du permien et du trias... gorjanci and south of kostanjevica (southeast slovenia) and their significance for the geotectonics of the larger area].geoloπki vjesnik, zagreb, svezak 42, p. 7-13, 4 pl. h.-t. (i-iv). bulle, j. (1973): le trias dans la région de titov veles (zone du vardar macédoine yougoslave).annales scientifiques de l’université de besançon, géologie, 3 série, fasc. 18, p. 97-104, 2 pl. (i-ii). buser, s., grad, k., ogorelec, b., r a m o v © , a. & ©ribar, l. (1988): stratigraphical, paleontological and sedimentological characteristics of upper permian beds in slovenia, nw yugoslavia.in: cassinis, g. (ed.): permian and triassic boundary in the south alpine segment of the western tethys, and additional regional reports. memorie della società geologica italiana, roma, vol. xxxiv (1986), p. 195-210, 4 pl. (1-4). b y s t r i c ký, j. (1957): príspevok ku poznaniu diplopór triasu gemeríd [beitrag zur kenntnis der diploporen der gemeriden-trias].geologický s b o r n í k , bratislava, roëník viii, »íslo 2, p. 226-241, 5 pl. h.-t. (iii-vii). b y s t r i c ký, j. (1959): výskyt riasy diplopora annu latissima pia v slovenskom krase [vorkommen der alge diplopora annulatissima p i a im gebirge s l o v e n s ký k r a s].geologické práce, bratislava, zprávy 16, p. 177-182, 2 pl. h.-t. (xi-xii). b y s t r i c ký, j. (1962): nové dasycladaceae triasu slovenského krasu [new d a s y c l a d a c e a e of the triassic in the slovak karst].geologický s b o r n í k , bratislava, roëník xiii, »íslo 2, p. 227-240, 2 pl. h.-t. (iii-iv). b y s t r i c ký, j. (1964): s l o v e n s ký kras. stratigrafia a dasycladaceae mezozoika slovenského krasu [s t r atigraphie und dasycladaceen des gebirges slovensky kras]. ú s t r e d ný ústav geologický, bratislava, 204 p., 38 pl. h.-t. (i-xxxviii). b y s t r i c ký, j. (1966): la stratigraphie et les dasycladacées du trias moyen de la série du drienok.g e o l o g i c ký sborník geologica carpathica, bratislava, roëník xvii, »íslo 2, p. 241-257, 4 pl. h.-t. (v-viii). b y s t r i c ký, j. (1967a): o veku “choëských dolomitov”.»asopis pro mineralogii a geologii, praha, roëník 12, »íslo 3, p. 247-252, 2 pl. h.-t. (i-ii). b y s t r i c ký, j. (1967b ): die obertriadischen dasycladazeen der westkarpaten.geologický sborník geologica carpathica, bratislava, roëník xviii, »íslo 2, p. 285-309, 18 pl. h.-t. (i-xviii). b y s t r i c ký, j. (1975): genus aciculella pia, 1930 (kalkalgen) in der trias der westkarpaten.geologický zborník geologica carpathica, bratislava, vol. xxvi, n° 1, p. 1-20, 4 pl. (i-iv). b y s t r i c ký, j. (1978): diplopora borzai nov. spec. (dasycladaceae) of the upper triassic of the muráň plateau (the west carpathians mountains, slovakia).geologický zborník geologica carpathica, bratislava, vol. 29, n° 2, p. 327-336, 2 pl. (1-2). b y s t r i c ký, j. (1979): dasycladaceae of the upper triassic of the stratenská hornatina mountains (the west carpathians).geologický zborník geologica carpathica, bratislava, vol. 30, n° 3, p. 321-340, 8 pl. (i-viii). b y s t r i c ký, j. (1982): attribution to the stráæovská hornatina mts. triassic reef complex stratigraphy on the basis of dasycladaceae (the west carpathians mts., slovakia).geologický zborník geologica carpathica, bratislava, vol. 33, n° 1, p. 79-88, 4 pl. (1-4). b y s t r i c ký, j. (1983): physoporella croatica h e ra k, 1958 of the slovak karst anisian (slovakia, the west carpathians mts.).geologický zborník geologica carpathica, bratislava, vol. 34, n° 5, p. 507-533, 5 pl. (i-v). b y s t r i c ký, j. (1986): stratigraphic ranging and zonation of dasycladal algae in the west carpathians mts., triassic.mineralia slovaca, bratislava, vol. 18, n° 4, p. 289-321, 6 pl. (i-vi). b y s t r i c ký, j. & veizer, j. (1965): t r i a d i s c h e dasycladaceen in der hochtatrischen hüllenserie der hohen tatra.geologický sborník, bratislava, roëník xvi, »íslo 1, p. 11-18, 2 pl. h.-t. (iii-iv). »anovi∆, m. (1965): the stratigraphic section of boring grahovo-1 (gr-1).vesnik, serija a (geologija) [bulletin, série a (géologie)], beograd, knjiga [tome] xxi (1963), p. 43-64, 7 pl. (1-7). »anovi∆, m. & kemenci, r. (1972): trijaski sedimenti u dubokim istraænim buπotinama u vojvodini [triassic sediments in deep exploratory bornholes in v o j v o d i n a].geoloπki anali balkanskoga poluostrva [annales géologiques de la péninsule balkaniq u e], beograd, knjiga [t o m e] xxxvii, sveska [fasc.] 2, p. 19-31, 5 pl. h.-t. (i-v). » a n o v i ∆, m. & kemenci, r. (1988): m e z o z o i k podine panonskog basena u vojvodini. stratigrafija i facije, magmatizam, paleogeografija [the mesozoic of the pannonian basin in vojvodina (yugoslavia). stratigraphy and facies, magmatism, paleog e o g r a p h y].matica srpska, odeljenje za prirodne nauke, novi sad, 339 p., 103 pl. h.-t. (i-ciii). carannante, g., carbone, f., catenacci, v. & simone, l. (1978): i carbonati triassici dei monti aurunci: facies deposizionali e diagenetiche.bollettino della società geologica italiana, roma, vol. 97, p. 687-698. casati, p., jadoul, f., nicora, a., marinelli, m., fantini sestini, n. & fois, e. ( 1 9 8 2 ) : geologia della valle del’anisei e dei gruppi m. popera-tre cime di lavaredo (dolomiti orientali).168 geologia croatica 53/1 rivista italiana di paleontologia e stratigrafia, milano, nuova serie, pubbl. n° 364 (1981), vol. 87, n° 3, p. 371-510, 4 pl. (32-35). cati, a., sartorio, d. & venturini, s. (1987): carbonate platforms in the subsurface of the northern adriatic area.memorie della società geologica italiana, roma, vol. 40, p. 295-308, 2 pl. (1-2). chiocchini, m. &. mancinelli, a. (1977): microbiostratigrafia del mesozoico in facies di piattaforma carbonatica dei monti aurunci (lazio meridionale).studi geologici camerti, camerino, vol. iii, p. 109-152, 48 pl. h.-t. (i-xlviii). chiocchini, m. &. mancinelli, a. (1978): ricerche geologiche sul mesozoico del gran sasso d’italia (abruzzo). iii. corelazioni microbiostratigrafiche tra facies di margine della piattaforma carbonatica e facies pelagiche del giurassico e cretaceo inferiore.studi geologici camerti, camerino, vol. iv, p. 19-35, 11 pl. h.-t. (i-xi). christodoulou, g. & tsaïla-monopolis, s. (1975): eastern hellenic zone microfacies.g e ological and geophysical research, athens, vol. vxii, n° 1, 63 p., 75 pl. h.-t. (i-lxxv). chuvashov, b.i. (1974): permskie izvestkovye vodorosli urala.in: vodorosli, brakhiopody i miospory iz permskikh otlozhenij zapadnogo urala (sbornik po voprosam stratigrafii, n° 20). trudy instituta geologii i geokhimii, akademija nauk sssr, sverdlovsk, vyp. 109, p. 3-52, 24 pl. h.-t. (ixxiv). chuvashov, b.i. & anfimov, a.l. (1988): novye izvestkovye vodorosli srednego karbona nizhnej permi urala i priural’ja.in: d u b a t o l o v , v.n. & moskalenko, t.a. ( e d s . ): i z v e s t k o v y e vodorosli i stromatolity. sistematika, biostratigrafija, facial’nyjanaliz. sbornik nauchnykh trudov, akademija nauk sssr, sibirskoe otdelenie, institut geologii i geofiziki. “nauka”, novosibirsk, p. 5470, 9 pl. h.-t. (xxi-xxix). c h u v a s h o v, b.i., shuysky, v.p. & ivanova, r.m. (1993): stratigraphical and facies complexes of the paleozoic calcareous algae of the urals.in: barattolo, f., de castro, p. & parente, m. (eds.): studies on fossil benthic algae. bollettino della società paleontologica italiana, special volume n° 1, modena, p. 93-119, 14 pl. (1-14). ciarapica, g., cirilli, s., martini, r., rettori, r., zaninetti, l. & salvini-bonnard, g. (1990): carbonate buildups and associated facies in the monte facito formation (southern apennines).bollettino della società geologica italiana, roma, vol. 109, p. 151-164. ciarapica, g., cirilli, s., martini, r., rettori, r. & zaninetti, l. (1987): “anidriti di burano” et “formation du monte cetona” (nouvelle formation), biostratigraphie de deux séries-types du trias supérieur dans l’apennin septentrional.revue de paléobiologie, genève, vol. 6, n° 2, p. 341-409, 31 pl. (i-xxxi). climaco, a., boni, m., iannace, a. & zamparelli, v. (1997): platform margins, microbial/ serpulids bioconstructions and slope-to-basin sediments in the upper triassic of the ‘verbicaro unit’ (lucania and calabria, southern italy).facies, erlangen, 36, p. 37-56, 6 pl. (11-16). conrad, m.a., praturlon, a. & radoi»i∆, r. (1973): reinstatement of the genus s a l p i n g o p o r e l l a p i a (dasycladaceae), followed by s a l p i n g o p o r e l l a s t e i n h a u s e r i , n. sp.compte rendu des séances de la société de physique et d’histoire naturelle de genève, ns, vol. 7 (1972), fasc. 2-3, p. 103-111, 1 pl. h.-t. (i). conti, s. (1954): studi geologici sulle alpi occidentali (1° contributo). stratigrafia della “formazione dei calcescisti” nelle alpi marittime e cozie.bollettino del servizio geologico d’italia, roma, vol. lxxv, fasc. 2°, p. 489-521, 2 pl. (i-ii). cosijn, j. (1928): de geologie van de valli di olmo al brembo.leidsche geologische mededeelingen, leiden, deel ii, aflevering 4, p. 251-324, 4 pl. h.-t. (37-40). cros, p. & lemoine, m. (1966): d a s y c l a d a c é e s nouvelles ou peu connues du lias inférieur des dolomites et de quelques autres régions méditerranéennes (1r e partie).revue de micropaléontologie, paris, vol. 9, n° 3, p. 156-168, 2 pl. (1-2). dawson, o. (1993): fusuline foraminiferal biostratigraphy and carbonate facies of the permian ratburi limestone, saraburi, central thailand.journal of micropalaeontology, plymouth, vol. 12, n° 1, p. 9-33, 9 pl. (1-9). de castro, p. (1979): osservazioni su d i p l o p o r a nodosa s c h a f h ä u t l 1863 (alga verde dasicladacea) delle scogliere triassiche della lucania (appennino meridionale).bollettino della società dei naturalisti in napoli, vol. lxxxviii, 91 p., 20 pl. (i-xx). de castro, p. (1990): studies on the triassic carbonates of the salerno province (southern italy): the croci d’acerno sequence.bollettino della società geologica italiana, roma, vol. 109, p. 187-217, 17 pl. (1-17). de castro, p. (1993): observations on campbelliel l a radoi»i∆, 1959 and n e o t e u t l o p o r e l l a b a ssoullet et al., 1978 (green algae, dasycladales).in: barattolo, f., de castro, p. & parente, m. (eds.): studies on fossil benthic algae. bollettino della società paleontologica italiana, modena, special volume n° 1, p. 121-184, 21 pl. (1-21). 169granier & grgasoviê: les algues dasycladales du permien et du trias... de castro, p. (1997): introduzione allo studio in sezione sottile delle dasicladali fossili [an approach to thin-section study of fossil dasycladales].quaderni dell’accademia pontaniana, napoli, n° 2, 261 p., 30 pl. h.-t. (1-30). de lorenzo, g. (1896): fossili del trias medio di lagonegro.palaeontographia italica, memorie di paleontologia, pisa, vol. ii, p. 113-148, 6 pl. h.-t. (xv-xx). de meijer, j.j. (1971): carbonate petrology of algal limestones (lois-ciguera formation, upper carboniferous, león, spain).leidse geologische mededelingen, leiden, deel 47, aflevering 1, p. 1-97, 21 pl. (i-xxi). de sitter, l.u. & de sitter-koomans, c.m. (1949): the geology of the bergamasc alps, lombardia, italy. contributions to the geology of the bergamasc alps, n° 27.leidse geologische mededelingen, leiden, deel 14 b, p. 1-257, 36 pl. (ixxxvi). deloffre, r. (1970): niveau à algues dans le sparnacien de la région de plagne (petites-pyrénées haute-garonne) et observations sur le genre n e o meris lamouroux, 1816.bulletin du centre de recherches pau snpa, vol. 4, n° 2, p. 353-379, 5 pl. (1-5). deloffre, r. (1988): nouvelle taxonomie des algues dasycladales.bulletin des centres de recherches exploration-production elf-aquitaine, pau, vol. 12, n° 1, p. 165-217, 13 pl. (1-13). delvolvé, j.-j., perret, m.-f. & vachard, d. (1987): découverte du kachirien (moscovien inférieur) à fusulines et algues dans le massif des cinco villas (pyrénées basques, espagne).géobios, lyon, n° 20, fasc. 4, p. 541-548, 1 pl. (1). dercourt, j. (1964): 1r e thèse. contribution à l’étude géologique d’un secteur du péloponnèse septentrional.thèses doctorat ès sciences naturelles, université de paris, série a, n° 4251, n° d’ordre 5102. annales géologiques des pays helléniques, athènes, t. xv, 418 p., 80 pl. h.-t. (ilxxx). di stefano, p. (1981a): diplopora panormitana n . sp. una nuova specie di dasicladacea (alga verde) del trias dei monti di palermo (sicilia).bollettino della società dei naturalisti in napoli, vol. lxxxix (1980), p. 73-94, 4 pl. (i-iv). di stefano, p. (1981b): 2.2.4. cozzo di lupo reef: late triassic depositional model and role of algal communities.in: catalano, r. & d’argenio, b. (eds.): paleogeographic evolution of a continental margin in sicily. guide-book of the field trip in western sicily. penrose conference on controls of carbonate platform evolution (palermo, 1214 sept. 1981), p. 70-76. di stefano, p. & senowbari-daryan, b. (1985): upper triassic dasycladales (green algae) from the palermo mountains (sicily, italy).geologica romana, roma, vol. xxiv, p. 189-218, 7 pl. (i-vii). diaconu, m. & dragastan, o. (1969): t r i a s s i c calcareous algae from the apuseni mountains (rumania).review of palaeobotany and palynology, amsterdam, vol. 9, n° 1-2, p. 63-101, 10 pl. (ix). diener, c. (1925): leitfossilien der trias. wirbellose tiere und kalkalgen.in: gürich, g. (ed.): leitfossilien. ein hilfsbuch zum bestimmen von versteinerungen bei geologischen arbeiten in der sammlung und im felde, lief. 4. verlag von gebrüder borntraeger, berlin, 118 p., 28 pl. h.-t. (ixxviii). dieni, i. & spagnulo, g. (1964): alghe calcaree nell’anisico del dosso dei morti (adamello sudorientale).memorie della accademia patavina di ss.ll.aa., classe di scienze matematiche e naturali, padova, vol. lxxvi (1963-1964), p. 1-13, 2 pl. h.-t. (i-ii). d i m i t r i j e vi ∆, m., p a n t i ∆, s., r a d o i » i ∆ , r. & stefanovska, d. (1968): litostratigrafski i biostratigrafski stubovi mezozoika u oblasti gackosutjeska-drina.vesnik, serija a (geologija) [b u lletin, série a (géologie)], beograd, knjiga [t o m e] xxvi, p. 39-70, 24 pl. (i-xxiv). dondi, l. & papetti, i. (1965): sul ritrovamento di una microfacies con m i o g y p s i n a e l e p i d o c y c l i n a a l fondo del pozzo contursi 1 (m 3478), nel cilento.geologica romana, roma, vol. iv, p. 7-20, 9 pl. h.t. (i-ix). d r a g a s t a n, o. (1980): alge calcaroase din mezozoicul ş i terţ iarul româniei.editura academiei republicii socialiste românia, bucureşti, 169 p., 20 pl. h.-t. (i-xx). d r a g a s t a n, o. (1981): mesozoic dasycladaceae from romania: distribution and biostratigraphical importance.facies, erlangen, 4, p. 165-196, 1 pl. (9). dragastan, o. & grǎdinaru, e. (1975): asupra unor alge, foraminifere, sphinctozoare şi microproblematice din triasicul din carpaţii orientali şi dobrogea de nord [some triassic algae, foraminiferae, sphinctozoa and microproblematicae from the eastern carpathians and north dobrogea].studii ş i cercetǎri de geologie, geofizicǎ, geografie, seria geologie, bucureşti, tomul 20, n° 2, p. 247254, 6 pl. h.-t. (i-vi). d r a g a s t a n, o., mertmann, d. & ahmed, s. (1990): some algal species from the upper permian deposits, sakesar-section, salt range, pakistan.revue de paléobiologie, genève, vol. 9, n° 1, p. 4963, 3 pl. (i-iii). 170 geologia croatica 53/1 dragastan, o., papanikos, d. & papanikos, p . (1985): foraminifères, algues et microproblematica du trias de messopotamos, épire (grèce continentale).revue de micropaléontologie, paris, vol. 27, n° 4, p. 244-248, 1 pl. (1). dragastan, o. & trappe, j. (1986): some dasyclad algae of the sinemurian from the north-western iberian chains (spain).paläontologische zeitschrift, stuttgart, vol. 60, n° 3/4, p. 169-179. dronov, v.i., g aźd z i c k i , a. & melnikova, g.k. (1982): die triadischen riffe im südöstlichen pamir.facies, erlangen, 6, p. 107-128, 3 pl. (1416). dullo, w.c. (1980a): über ein neues vorkommen von tisovec-kalk in den südwestlichen gesäusebergen (admont, steiermark).mitteilungen der gesellschaft der geologieund bergbaustudenten in österreich, innsbruck, band 26, p. 155-165, 2 pl. (12). dullo, w.c. (1980b): pälaontologie, fazies und geochemie der dachstein-kalke (ober-trias) im südwestlichen gesäuse, steiermark, österreich.facies, erlangen, 2, p. 55-122, 5 pl. (9-13). dullo, w.c. & lein, r. (1982): facies and environment of the leckkogel beds (carnian; alps).facies, erlangen, 6, p. 25-36, 2 pl. (3-4). –ur–anovi∆, æ. (1968): eine neue form von t r o c h o l i n a aus den karnischen ablagerungen südwestlich von vojsko (slowenien jugoslawien).geoloπki vjesnik, zagreb, svezak 21 (1967), p. 105-110, 1 pl. h.-t. (i). elias, m.k. (1947): permopora keenae , a new late permian alga from texas.journal of paleontology, tulsa, vol. 21, n° 1, p. 46-58, 1 pl. h.-t. (18). ellenberger, f. (1958): étude géologique du pays de vanoise.mémoires pour servir à l’explication de la carte géologique détaillée de la france, paris, 561 p., 42 pl. h.-t. (1-42), 8 panoramas (i-viii). elliott, g.f. (1956): further records of fossil calcareous algae from the middle east.micropaleontology, new york, vol. 2, n° 4, p. 327-334, 2 pl. (12) elliott, g.f. (1958): fossil microproblematica from the middle east.micropaleontology, new york, vol. 4, n° 4, p. 419-428, 3 pl. (1-3). elliott, g.f. (1968a): permian to palaeocene calcareous algae (dasycladaceae) of the middle east.bulletin of the british museum (natural history), geological (palaeontological) series, london, supplement 4, 111 p., 24 pl. h.-t. (1-24). elliott, g.f. (1968b): three new tethyan dasycladaceae (calcareous algae) of the middle east.palaeontology, london, vol. 11, part 4, p. 491-497, 3 pl. h.-t. (93-95). elliott, g.f. (1971): the nature of a c i c u l e l l a p i a (calcareous algae).palaeontology, london, vol. 14, part 4, p. 629-636, 2 pl. h.-t. (118-119). elliott, g.f. & süssli, p. (1975): i m p e r i e l l a g e n . nov., a new alga from the ruteh limestone, upper permian (central alborz mountains, north iran).eclogae geologicae helvetiae, basel, vol. 68, n° 2, p. 449-455, 1 pl. h.-t. (i). emberger, j. (1976): les algues (euchlorophyceae, p r a s i n o p h y c e a e , r h o d o p h y c e a e) du carbonifère et du permien. essai d’un inventaire bibliographique, géographique, stratigraphique.bulletin de l’institut de géologie du bassin d’aquitaine, talence, n° spécial, 168 p. emberger, j. (1979): les algues (euchlorophyceae, p r a s i n o p h y c e a e , r h o d o p h y c e a e) du trias. essai d’un inventaire bibliographique, géographique, stratigraphique.bulletin de l’institut de géologie du bassin d’aquitaine, talence, n° spécial, 157 p. endo, r. (1951): 208. stratigraphical and paleontological studies of the later paleozoic calcareous algae in japan i. several new species from the sakamotozawa section, hikoroichi-mura, kesen-gun, in the kitakami mountainous land.transactions and proceedings of the palaeontological society of japan, n.s., tokyo, n° 4, p. 121-129, 2 pl. h.-t. (1011). endo, r. (1952a): 210. stratigraphical and paleontological studies of the later paleozoic calcareous algae in japan, ii. several previously described species from the sakamotozawa section, hikoroichi-mura, kesen-gun, in the kitakami mountainous land.transactions and proceedings of the palaeontological society of japan, n.s., tokyo, n° 5, p. 139-144, 1 pl. h.-t. (12). endo, r. (1952b): stratigraphical and paleontological studies of the later paleozoic calcareous algae in japan, iii. a few species from the maiya section, maiya-machi, tome-gun, miyagi-ken.the science reports of the saitama university, series b (biology and earth sciences), urawa, vol. i, n° 1, p. 2328, 1 pl. h.-t. (i). e n d o, r. (1952c): 225. stratigraphical and paleontological studies of the later paleozoic calcareous algae in japan, iv. notes on the calcareous algae of the omi limestone.transactions and proceedings of the palaeontological society of japan, n.s., tokyo, n° 8, p. 241-248, 1 pl. h.-t. (23). endo, r. (1953a): stratigraphical and paleontological studies of the later paleozoic calcareous algae in japan, v. several species from the iwaizaki limestone, motoyoshi-gun, in the kitakami mountainous land.japanese journal of geology and geography, tokyo, vol. xxiii, p. 117-126, 2 pl. h.-t. (xi-xii). endo, r. (1953b): stratigraphical and paleontological studies of the later paleozoic calcareous algae in 171granier & grgasoviê: les algues dasycladales du permien et du trias... japan, vi. several interesting species from the kwantô mountainous land and a new genus from kinshôzan, akasaka, gifu-ken.the science reports of the saitama university, series b (biology and earth sciences), urawa, vol. i, n° 2, p. 97-104, 1 pl. h.-t. (ix). e n d o, r. (1954): stratigraphical and paleontological studies of the later paleozoic calcareous algae in japan, viii. several species from kinshô-zan, akasaka-machi, gifu-ken.the science reports of the saitama university, series b (biology and earth sciences), urawa, vol. i, n° 3, p. 209-216, 1 pl. h.-t. (xviii). endo, r. (1956): stratigraphical and paleontological studies of the later paleozoic calcareous algae in japan, x. fossil algae from the kwantô and kitakami mountains.the science reports of the saitama university, series b (biology and earth sciences), urawa, vol. ii, n° 2, p. 221-248, 10 pl. h.-t. (22-31). endo, r. (1957): stratigraphical and paleontological studies of the later paleozoic calclaeous algae in japan, xi. fossil algae from the taishaku district, hiroshima-ken, and kitami-no-kuni, hokkaido.the science reports of the saitama university, series b (biology and earth sciences), urawa, vol. ii, n° 3, p. 279-305, 8 pl. h.-t. (37-44). endo, r. (1958): 347. stratigraphical and paleontological studies of the later paleozoic calcareous algae in japan, xiii. a restudy of the genus p h y s o p o r e l l a.transactions and proceedings of the palaeontological society of japan, new series, tokyo, n° 31, p. 265-269, 1 pl. h.-t. (39). endo, r. (1959): stratigraphical and paleontological studies of the later paleozoic calcareous algae in japan, xiv. fossil algae from the nyugawa valley in the hida massif.the science reports of the saitama university, series b (biology and earth sciences), urawa, vol. iii, n° 2, p. 177-207, 13 pl. h.-t. (30-42). endo, r. (1960): stratigraphical and paleontological studies of the later paleozoic calcareous algae in japan, xv. a restudy of the genus e p i m a s t o p o r a . the science reports of the saitama university, series b (biology and earth sciences), urawa, vol. iii, n° 3, p. 267-270, 1 pl. h.-t. (44). endo, r. (1961a): phylogenetic relationships among the calcareous algae.the science reports of the saitama university, series b (biology and earth sciences), urawa, commemorative volume dedicated to professor riuji endo, p. 1-52, 17 pl. h.-t. (117). endo, r. (1961b): stratigraphical and paleontological studies of the later paleozoic calcareous algae in japan, xvi. fossil algae from the ominagahama district.the science reports of the saitama university, series b (biology and earth sciences), urawa, commemorative volume dedicated to professor riuji endo, p. 77-118, 19 pl. h.-t. (1-19). endo, r. (1961c): stratigraphical and paleontological studies of the later paleozoic calcareous algae in japan, xvii. fossil algae from the akiyoshi limestone group.the science reports of the saitama university, series b (biology and earth sciences), urawa, commemorative volume dedicated to professor riuji endo, p. 119-142, 7 pl. h.-t. (1-7). endo, r. (1968a): fossil algae from mindoro oriental province, mindoro island, the philippines. contributions to the geology and paleontology of southeast asia, lii.in: kobayashi, t. & toriyama, r. (eds.): geology and paleontology of southeast asia, volume 4. university of tokyo press, tokyo, p. 211-219, 3 pl. h.-t. (xxxiii-xxxv). endo, r. (1968b): on the geographical and stratigraphical distribution of the upper paleozoic algal remains in the circum-pacific regions.bull. tokyo college of domestic science, tokyo, p. 1-6, 2 pl. h.-t. (i-ii). endo, r. (1969): fossil algae from the khao phlong phrab district in thailand. contributions to the geology and paleontology of southeast asia, lxxiv.in: kobayashi, t. & toriyama, r. (eds.): geology and paleontology of southeast asia, volume 7. university of tokyo press, tokyo, p. 3385, 38 pl. h-t. (v-xlii). endo, r. & hashimoto, w. (1955): 169. unquestionably paleozoic (permian) fossils found in hokkaido, japan.japan academy, procreedings, tokyo, vol. 31, n° 10, p. 704-708. endo, r. & horiguchi, m. (1957): 14. stratigraphical and paleontological studies of the later paleozoic calcareous algae in japan, xii. fossil algae from the fukuji district in the hida massif.japanese journal of geology and geography, tokyo, vol. xxviii, n° 4, p. 169-177, 3 pl. h.-t. (xiii-xv). endo, r. & kanuma, m. (1954): s t r a t i g r a p h i c a l and paleontological studies of the later paleozoic calcareous algae in japan, vii. geology of the mino mountain land and southern part of hida plateau, with descriptions of algal remains found in those districts.the science reports of the saitama university, series b (biology and earth sciences), urawa, vol. i, n° 3, p. 177-208, 5 pl. h.-t. (xiii-xvii). epting, m., unland, w., schmidt, k. & christodoulides, a. (1976): middle triassic sediments of selected regions in the southern alps (italy) and their significance for paleogeographic and paleostructural evolution.neues jahrbuch für geologie und paläontologie, abhandlungen, stuttgart, band 151, heft 1, p. 1-30. 172 geologia croatica 53/1 ercegovac, m.d. (1981): m i k r o p a l e o n t o l o g i j a . mikropaleobotanika.nauëna knjiga, beograd, 323 p., 32 pl. (i-xxxii). faber, p. & riding, r. (1979): u r a l o p o r e l l a ( m icroproblematicum) from the middle devonian of the eifel (west germany).neues jahrbuch für geologie und paläontologie, monatshefte, stuttgart, heft 3, p. 139-146. farabegoli, e. & guasti, m. (1980): a n i s i a n lithostratigraphy and paleogeography of m. rite (cadore, southeastern dolomites).rivista italiana di paleontologia e stratigrafia, milano, vol. 85, n° 3-4, p. 909-930, 1 pl. h.-t. (65). farabegoli, e., jadoul, f. & martines, m. (1985): stratigrafia e paleogeografia anisiche delle alpi giulie occidentali (alpi meriodionali italia).rivista italiana di paleontologia e stratigrafia, milano, vol. 91, n° 2, p. 147-196, 2 pl. h.-t. (5-6). farabegoli, e. & levanti, d. (1982): t r i a s s i c stratigraphy and microfacies of the monte pleros (western carnia, italy).facies, erlangen, 6, p. 3758, 3 pl. (5-7). fenninger, a. (1969): ein beitrag zur flora und fauna im raume von golpaygan (iran).verhandlungen der geologischen bundesanstalt, wien, jahrgang 1969, heft 1, p. 22-32, 3 pl. h.-t. (1-3). fenninger, a. (1982): dasycladaceen (kalkalgen) aus dem schlerndolomit des gartnerkofel (karnische alpen).carinthia ii, klagenfurt, jahrgang 92, sonderheft 172, p. 105-107. fenninger, a. & holzer, h.-l. (1972): f a z i e s und paläogeographie des oberostalpinen malm.mitteilungen der geologischen gesellschaft in wien, band 63 (1970), p. 52-141, 19 pl. h.-t. (1-19). flajs, g. (1977): die ultrastrukturen des kalkalgenskeletts.palaeontographica, stuttgart, abteilung b, band 160, lieferung 4-6, p. 69-128, 17 pl. h.-t. (117). flügel, e. (1966): algen aus dem perm der karnischen alpen.carinthia ii, klagenfurt, sonderheft 25, 76 p., 11 pl. h.-t. (1-11). flügel, e. (1972): mikrofazielle untersuchungen in der alpinen trias. methoden und probleme.in: mikrofazies und mikrofauna der alpinen trias und deren nachbargebiete (symposium innsbruck, 20.23. märz 1972). mitteilungen der gesellschaft der geologieund bergbaustudenten in österreich, innsbruck, band 21, teil 1, p. 9-64, 9 pl. (i-ix). flügel, e. (1975): kalkalgen aus riffkomplexen der alpin-mediterranen obertrias. beiträge zur paläontologie und mikrofazies obertriassischer riffe, 1.verhandlungen der geologischen bundesanstalt, wien, jahrgang 1974, heft 2-3, p. 297-346, 4 pl. (14). flügel, e. (1977): 34. environmental models for upper paleozoic benthic calcareous algal communities.in: flügel, e. (ed.): fossil algae. recent results and developments. springer-verlag, berlin, p. 314-343, 4 pl. (1-4). flügel, e. (1978): microfazielle untersuchungsmethoden von kalken.springer-verlag, berlin, 454 p., 32 pl. (1-32). flügel, e. (1979): paleoecology and microfacies of permian, triassic and jurassic algal communities of platform and reef carbonates from the alps.in: 2 ème symposium international sur les algues fossiles (paris, 23-26 avril 1979). bulletin des centres de recherches exploration-production elf-aquitaine, pau, vol. 3, n° 2, p. 569-587, 3 pl. (1-3). flügel, e. (1980): die mikrofazies der kalke in den trogkofel-schichten der karnischen alpen.in: die trogkofel-stufe im unterperm der karnischen alpen. carinthia ii, klagenfurt, sonderheft 36, p. 51-99, 14 pl. (1-14). flügel, e. (1981): paleoecology and facies of upper triassic reefs in the northern calcareous alps.in: t o o m e y, d.f. (ed.): european fossil reef models. sepm special publication, tulsa, n° 30, p. 291359. flügel, e. (1982): microfacies analysis of limestones.springer-verlag, berlin, 633 p., 53 pl. (153). flügel, e. (1986): zur mikrofazies oberanisischer riffkalke in den östlichen nordkarawanken, kärnten.carinthia ii, klagenfurt, jahrgang 96, sonderheft 176, p. 463-478, 5 pl. (1-5). flügel, e. (1987): reef mound-entstehung: algenmounds im unterperm der karnischen alpen.facies, erlangen, 17, p. 73-90, 3 pl. (7-9). flügel, e. (1990): “einschnitte” in der entwicklung permischer kalkalgen.mitteilungen des naturwissenschaftlichen vereines fur steiermark, graz, band 120, p. 99-124, 4 pl. (1-4). flügel, e. (1991): chapter 21. triassic and jurassic marine calcareous algae: a critical review.in: ridi n g, r. (ed.): calcareous algae and stromatolites. springer-verlag, berlin, p. 481-503. flügel, e., di stefano, p. & senowbari-daryan, b. (1991): microfacies and depostional structure of allochthonous carbonate base-of-slope deposits. the late permian pietra di salomone megablock, sosio valley (western sicily).facies, erlangen, 25, p. 73-90, 13 pl. (36-48). flügel, e. & flügel-kahler, e. (1980): a l g e n aus den kalken der trogkofel-schichten der karnischen alpen.in: die trogkofel-stufe im unterperm der karnischen alpen. carinthia ii, klagenfurt, sonderheft 36, p. 113-182, 14 pl. (1-14). 173granier & grgasoviê: les algues dasycladales du permien et du trias... flügel e., flügel-kahler, e., martin, j.m. & martin-algarra, a. (1984): middle triassic reefs from southern spain.facies, erlangen, 11, p. 173-218, 11 pl. (20-30). flügel, e. & hagdorn, h. (1993): dasycladaceen aus dem oberen muschelkalk (mitteltrias) des hohenloher landes, süddeutschland.zitteliana, münchen, 20, p. 93-103, 2 pl. (1-2). flügel, e. & kahler, f. (1988): f a z i e l l s t r a t igraphische entwicklung im paläozoikum von belemedik (“bagdadbahn-profil”), südanatolien.facies, erlangen, 18, p. 123-168, 10 pl. (12-21). flügel, e. & kirchmayer, m. (1963): t y p l o k alität und mikrofazies des gutensteiner kalkes (anis) der nordalpinen trias.mitteilungen des naturwissenschaftlichen vereines für steiermark, graz, band 93, p. 106-135, 4 pl. h.-t. (viii-xi). flügel, e., k o c h a n s k y d e v i d é , v. & r am o v © , a. (1984): a middle permian calcisponge/ algal/cement reef: straæa near bled, slovenia.facies, erlangen, 10, p. 179-256, 19 pl. (24-42). flügel, e. & kraus, s. (1988): the lower permian sexten breccia (sexten dolomites) and tarvis breccia (carnic alps): microfacies, depositional environment and paleotectonic implications.in: cassinis, g. (ed.): permian and triassic boundary in the south alpine segment of the western tethys, and additional regional reports. memorie della soci età geologica italiana, roma, vol. xxxiv (1986), p. 67-90, 5 pl. (1-5). flügel, e. & mörtl, j.(1982): m i t t e l t r i a d i s c h e dasycladaceen (kalkalgen) sowie permoskyth aus der bohrung k, südlich edling, bezirk völkermarkt, kärnten.carinthia ii, klagenfurt, jahrgang 92, sonderheft 172, p. 97-104. flügel, e. & mu, x.-n. (1982): upper triassic dasycladaceae from eastern tibet.facies, erlangen, 6, p. 59-74, 3 pl. (8-10). flügel, e., r a m o v © , a. & bucur, i.i. (1994): middle triassic (anisian) limestones from bled, northwestern slovenia: microfacies and microfossils.geologija, ljubljana, knjiga 36 (1993), p. 157-181, 7 pl. (1-7). flügel, e., senowbari-daryan, b. & stanley, g.d. j r. (1989): late triassic dasycladacean alga from northeastern oregon: significance of first reported occurrence in western north america.journal of paleontology, tulsa, vol. 63, n° 3, p. 374-381. flügel, h. (1962): geologische detailaufnahmen 1961 im jungpaläozoikum zwischen waidegger und straniger alm (karnische alpen).carinthia ii, klagenfurt, jahrgang 72, sonderheft 152, p. 91-96. flügel, h. (1963): algen und problematica aus dem perm süd-anatoliens und irans.sitzungsberichte der österreichische akademie der wissenschaften, mathematisch-naturwissenschaftliche klasse, wien, abteilung i, band 172, heft 1-2, p. 85-95, 2 pl. h.-t. (1-2). fois, e. (1979): a new dasycladaceans (calcareous algae) assemblage from triassic of m. popera (belluno, italy).rivista italiana di paleontologia e stratigrafia, milano, vol. 85, n° 1, p. 57-84, 6 pl. (1-6). fois, e. & jadoul, f. (1983): la dorsale paleocarnica anisica di pontebba.rivista italiana di paleontologia e stratigrafia, milano, vol. 89, n° 1, p. 3-30, 1 pl. (1). fontaine, h., khoo, h.p. & vachard, d. (1988): discovery of triassic fossils at bukit chuping, in gunung sinyum area, and at kota jin, peninsular malaysia.journal of southeast asian earth sciences, oxford, vol. 2, n° 3-4, p. 145-162. fontaine, h., nguyên, d.t. & vachard, d. (1986): appendix 6 discovery of permian limestone south of tara island in the calamian islands, philippines.c.c.o.p technical bulletin, bangkok, vol. 18, p. 161-167, 3 pl. (22-24). fontaine, h. & suteethorn, v. (1988): l a t e paleozoic and mesozoic fossils of west thailand and their environments.ccop technical bulletin, tokyo, vol. 20, 217 p., 46 pl. (1-46). gaetani, m., fois, e., jadoul, f. & nicora, a. (1981): nature and evolution of middle triassic carbonate buildups in the dolomites (italy).in: cita, m.b. & ryan, w.b.f. (eds.): carbonate platforms of the passive-type continental margins, present and past. marine geology, amsterdam, 44, p. 25-57. gaetani, m., gianotti, r., jadoul, f., ciarapica, g., cirilli, s., lualdi, a., paserri, l., pellegrini, m. & tannoia, g. (1987): c a rbonifero superiore, permiano e triassico nell’area lariana.memorie della società geologica italiana, roma, vol. xxxii (1986), p. 5-48, 3 pl. (1-3). gaetani, m. & gorza, m. (1989): the anisian (middle triassic) carbonate bank of camorelli (lombardy, southern alps).facies, erlangen, 21, p. 41-56, 5 pl. (9-13). g aździcki, a. & kowalski, w.r. (1974): green algae a c i c u l e l l a p i a from the muschelkalk of the holy cross mts. (poland).bulletin de l’académie polonaise des sciences, série des sciences de la terre, warszawa, vol. xxii, n° 1, p. 27-32, 2 pl. h.t. (i-ii). g aźd z i c k i, a. & kowalski, w.r. (1975): r e v ision of fossil sporangia a c i c u l e l l a and a c i c u l a r i a /dasycladaceae/ from the mesozoic of poland.in: first international symposium on fossil algae 174 geologia croatica 53/1 (erlangen, 6-10 octobre 1975), program and abstracts, p. 12-13. g aźd z i c k i, a., trammer, j. & zawidzka, k. (1975): foraminifers from the muschelkalk of southern poland.acta geologica polonica, warszawa, vol. 25, n° 2, p. 285298, 12 pl. (1-12). g aźd z i c k i, a. & smit, o.e. (1977): triassic foraminifers from the malay peninsula.acta geologica polonica, warszawa, vol. 27, n° 3, p. 319-332, 10 pl. h.-t. (1-10). genge, e. jr. (1958): ein beitrag zur stratigraphie der südlichen klippendecke im gebiet spillgerten-seehorn (berner oberland).eclogae geologicae helvetiae, basel, vol. 51, n° 1, p. 151-211, 8 pl. h.-t. (iviii). girty, g.h. (1908): the guadalupian fauna.united states geological survey, washington, professional paper 58, 651 p., 31 pl. (i-xxxi). glennie, k.w., boeuf, m.g.a., hughes clarke, m.w., moody-stuart, m., pilaar, w.f.h. & reinhardt, b.m. (1974): geology of the oman mountains.verhandelingen van het koninklijk nederlands geologisch minjbouwkundig genootschap [transactions of the royal dutch geological and mining society], deel 31, part one (text), 423 p., part two (tables and illustrations), part three (enclosures). glintzboeckel, c. & rabaté, j. (1964): microfaunes et microfaciès du permo-carbonifère du sud tunisien.international sedimentary petrographical series, e.j. brill, leiden, vol. vii, 45 p., 108 pl. h.t. (i-cviii). gortani, m. (1906): contribuzioni allo studio del paleozoico carnico. i la fauna permocarbonifera del col mezzodì presso forni avoltri.palaeontographia italica, memorie di paleontologia, pisa, vol. xii, p. 1-84, 3 pl. h.-t. (i-iii). grambast, l. (1969): la symétrie de l’utricule chez les clavatoracées et sa signification phylogénétique.compte rendu de l’académie des sciences, paris, série d, t. 269, p. 878-881, 4 pl. h.-t. (i-iv). granier, b. (1993): petralga project: advancement report.in: international symposium and field-meeting “alpine algae ‘93”, abstracts, wien, 3 p. granier, b. & deloffre, r. (1994): i n v e n t a i r e critique des algues dasycladales fossiles. ii° partie les algues dasycladales du jurassique et du crétacé.revue de paléobiologie, genève, vol. 12, n° 1 (1993), p. 19-65. granier, b. & deloffre, r.(1995): i n v e n t a i r e critique des algues dasycladales fossiles. iii° partie les algues dasycladales du permien et du trias.revue de paléobiologie, genève, vol. 14, n° 1, p. 49-84. granier, b., masse, j.-p. & berthou, p.-y. (1995): heteroporella lepina p r a t u r l o n, 1967, revisited (followed by taxonomic notes on the socalled “h e t e r o p o r e l l a ” species).in: piller, w.e. (ed.): proceedings of the international symposium and field-meeting “alpine algae ‘93”. beiträge zur paläontologie, wien, n° 19 (1994), p. 129-141, 2 pl. (1-2). g r g a s o v i ∆, t. (1997): upper triassic biostratigraphy and algae from æumberak (croatia).geologia croatica, zagreb, vol. 50/2, p. 201-214, 2 pl. (i-ii). groves, j.r. (1986): calcareous algae and associated microfossils from mid-carboniferous rocks in eastcentral idaho.journal of paleontology, tulsa, vol. 60, n° 2, p. 476-496. gümbel, c.w. (1872): die sogenannten nulliporen (l i t h o t h a m n i u m und d a c t y l o p o r a ) und ihre betheiligung an der zusammensetzung der kalkgesteine. zweiter theil: die nulliporen des thierreichs (d a c t y l o p o r i d e a e ) nebst nachtrag zum ersten theile.abhandlungen der ii. classe der kön. akademie der wissenschaften, mathem. phys. classe, münchen, band xi, abh. i, p. 231-290, 4 pl. h.-t. (d.i-iv). gümbel, c.w. (1873): ueber conodictyum bursi f o r m e e t a l l o n, einer foraminifere aus der gruppe der dactyloporideen.sitzungsberichten kön. bayer. akademie der wissenschaften, sitzung der mathem.-phys. classe, münchen, band iii, p. 282294, 1 pl. h.-t. (i). gümbel, c.w. (1874): ueber neue gyroporellen aus den gailthaler gebirge.verhandlungen der kaiserlich-königlichen geologischen reichsanstalt, wien, jahrgang 1874, n° 4, p. 79-80. gu©i∆, i., wohlfeil, h. & wohlfeil, k. (1984): zur altersstellung und fazies des kalkes von kalecik (devon) und der akdag-serie (trias) im nordöstichen teil von karaburun (westl. izmir, türkei).neues jahrbuch für geologie und paläontologie, abhandlungen, stuttgart, band 167, heft 3, p. 375404. güvenç, t. (1965, i n é d i t): étude stratigraphique et micropaléontologique du carbonifère et du permien des taurus occidentaux dans l’arrière-pays d’analaya (turquie).thèse, université de paris, 3 vol., 273 p., 52 pl. h.-t. (m1-19, f1-7, a1-16). güvenç, t. (1966a): représentants des bereselleae (algues calcaires) dans le carbonifère de turquie et description d’un nouveau genre: g o k s u e l l a n. g.bulletin de la société géologique de france, paris, 7° série, t. vii, n° 5 (1965), p. 843-850, 1 pl. h.-t. (xxxii). güvenç, t. (1966b): description de quelques espèces d’algues calcaires (gymnocodiacées et dasycladacées) du carbonifère et du permien des taurus 175granier & grgasoviê: les algues dasycladales du permien et du trias... occidentaux (turquie).revue de micropaléontologie, paris, vol. 9, n° 2, p. 94-103, 3 pl. (1-3). güvenç, t. (1970): description de deux espèces d’algues calcaires dans le permien des taurus (turquie).bulletin de la société géologique de france, paris, 7° série, t. xi, n° 3 (1969), p. 447-451, 1 pl. h.-t. (x). güvenç, t. (1972): un nouveau genre d’algue calcaire du permien, e m b e r g e r e l l a n. g.türkiye jeoloji kurumu bülteni [bulletin of the geological society of turkey], ankara, vol. xv, n° 1, p. 2125. güvenç, t. (1979): dasycladacées métaspondyles du paléozoïque supérieur et du trias.in: 2è m e s y m p osium international sur les algues fossiles (paris, 2326 avril 1979). bulletin des centres de recherches exploration-production elf-aquitaine, pau, vol. 3, n° 2, p. 625-637. haas, j., góczán, f., oravecz-scheffer, a., barabás-stuhl, á., majoros, gy. & bérczi-makk, a. (1988): permian-triassic boundary in hungary.in: cassinis, g. (ed.): permian and triassic boundary in the south alpine segment of the western tethys, and additional regional reports. memorie della società geologica italiana, roma, vol. xxxiv (1986), p. 221-241, 6 pl. (1-6). haas, j., rálisch-felgenhauer, e., oravecz-scheffer, e., nagy, e. & bérczimakk, a. (1988b): triassic key sections in the mid-transdanubian (igal) structural zone.acta geologica hungarica, budapest, vol. 31/1-2, p. 317, 3 fig., 7 pl. (i-vii). hagemeister, a. (1988): zyklische sedimentation auf einer stabilen karbonatplatform: die raibler schichten (karn) des drauzuges/kärnten (österreich).facies, erlangen, 18, p. 83-122, 6 pl. (6-11). hagn, h. (1955): fazies und mikrofauna der gesteine der bayerischen alpen.international sedimentary petrographical series, e.j. brill, leiden, vol. i, 174 p., 71 pl. (i-lxxi). haná»ek, j. (1976): nové poznatky o triase stráæovského a choëského príkrovu v stráæovskej hornatine.západné karpaty, bratislava, séria geológia 1, p. 125-149, 9 pl. h.-t. (i-ix). hanzawa, s. (1961): facies and micro-organisms of the paleozoic, mesozoic and cenozoic sediments of japan and her adjacent islands.international sedimentary petrographical series, e.j. brill, leiden, vol. v, 421 p., 148 pl. (i-cxlviii). harvey, w.h. (1859): characters of new algae, chiefly from japan and adjacent regions, collected by charles wright in the north pacific exploring expedition under captain john rodgers.proceedings of the american academy of arts and sciences, washington, t. 4, p. 327-335. hemleben, c. & freels, d. (1977): f o s s i l f ü h rende dolomitisierte plattenkalke aus dem “muschelkalk superior” bei montral (prov. tarragona, spanien).neues jahrbuch für geologie und paläontologie, abhandlungen, stuttgart, band 152, heft 2, p. 186-212. henrich, r. (1982): middle triassic carbonate margin development: hochstaufen zwieselmassif, northern calcareous alps, germany.facies, erlangen, 6, p. 85-106, 3 pl. (11-13). henrich, r. (1984): facies, dolomitization and karstification of lagoonal carbonates: triassic of the northern alps.facies, erlangen, 11, p. 109-156, 9 pl. (9-17). herak, m. (1950): ladiniëke dasycladaceae jugoslavije i njihovo stratigrafsko znaëenje.rad jugoslavenske akademije znanosti i umjetnosti, zagreb, knjiga 280, p. 115-141, 4 pl. h.-t. (i-iv). herak, m. (1957): some problems in the dasyclad genus d i p l o p o r a .micropaleontology, new york, vol. 3, n° 1, p. 49-52. herak, m. (1958): the dasyclad genus physoporella in the anisian of yugoslavia.journal of the palaeontological society of india, lucknow, birbal sahni memorial number, vol. 3, p. 59-63, 2 pl. h.-t. (13-14). herak, m. (1963): paleobotanika.©kolska knjiga, zagreb, xii + 180 p. herak, m. (1965): comparative study of some triassic dasycladaceae in yugoslavia [k o m p a r a t i v n i studij nekih trijaskih dasikladaceja u jugoslaviji]. geoloπki vjesnik, zagreb, svezak 18/1 (1964), p. 334, 15 pl. h.-t. (i-xv). herak, m. (1967a): mesozoische kalkalgen der insel chios (griechenland).neues jahrbuch für geologie und paläontologie, abhandlungen, stuttgart, band 129, heft 1, p. 97-104, 5 pl. h.-t. (6-10). herak, m. (1967b): anisische dasycladaceen vom gosaukamm (dachsteingebiet, österreich).mitteilungen der geologischen gesellschaft in wien, wien, band 59 (1966), heft 2, p. 213-217, 3 pl. h.-t. (1-3). herak, m. & kochansky, v. (1963): b ü k k h egységi újpaleozóos mészalgak [j u n g p a l ä o z o i s c h e kalkalgen aus dem bükk-gebirge (nordungarn)]. geologica hungarica, series paleontologica, budapest, fasc. 28, p. 45-77, 4 pl. h.-t. (i-iv). herak, m. & ©kalec, d. (1967): kalkalgen im perm des samoborer gebirges.geoloπki vjesnik, zagreb, svezak 20 (1966), p. 37-40, 1 pl. h.-t. (i). heritsch, f. (1934): die oberpermische fauna von æaæar und vrzdenec in den savefalten.vesnik geoloπkog instituta kraljevine jugoslavije, beo176 geologia croatica 53/1 grad, knjiga iii (1933), sveska 1 [bulletin du service géologique du royaume de yougoslavie, tome iii (1933), fascicule 1], p. 6-60, 2 pl. h.-t. (i-ii). hirsch, f. (1966): étude stratigraphique du trias moyen de la région de l’arlberg (alpes du lechtal, autriche).mitteilungen aus dem geologischen institut der eidgenössischen technischen hochschul und der universität zürich, n.f., n° 80, 87 p., 2 pl.photo. hohenstein, v. (1913): beiträge zur kenntnis des mittleren muschelkalks und des unteren trochitenkalks am östlichen schwarzwaldrand.geologische und palaeontologische abhandlungen, jena, neue folge, band 12, heft 2, 100 p., 8 pl. h.-t. (i-viii). holzer, h.l. (1967): nachweis von c l y p e i n a m ic h e l i n im cordevol der nördlichen kalkalpen.sitzungsberichte der österreichische akademie der wissenschaften, mathematisch-naturwissenschaftliche klasse, wien, abteilung i, band 176, heft 57, p. 71-80, 1 pl. h.-t. (1). homann, w. (1972): unterund tief-mittelpermische kalkalgen aus den rattendorfer schichten, dem trogkofel-kalk und dem treßdorfer kalk der karnischen alpen (österreich).senckenbergiana lethaea, frankfurt am main, band 53, n° 3/4, p. 135313, 10 pl. h.-t. (1-10). horiguchi, m. (1958): some calcareous algae in the central part of the kitakami mountains, iwate prefecture, northeastern japan.the science reports of the saitama university, series b (biology and earth sciences), urawa, vol. 3, n° 1, p. 131-139, 2 pl. h.-t. (27-28). horiguchi, m. (1961): a new algal fossil “velomor p h a”.the science reports of the saitama university, series b (biology and earth sciences), urawa, vol. 4, n° 1, p. 93-99, 3 pl. h.-t. (23-25). horowitz, a.s. & potter, p.e. (1971): i n t r o d u ctory petrography of fossils.springer-verlag, berlin, 302 p., 100 pl. (1-100). hurka, h. (1967): variationsstatistische untersuchungen an anisischen dasycladaceen aus den pragser dolomiten in südtirol.neues jahrbuch für geologie und paläontologie, abhandlungen, stuttgart, band 128, heft 1, p. 41-100, 2 pl. h.-t. (6-7). hurka, h. (1969): umbildungstendenzen der astformen in p h y s o p o r e l l a o l i g o p o r e l l a populationen (dasycladaceen) aus dem anis der pragser dolomiten (italien).neues jahrbuch für geologie und paläontologie, monatshefte, stuttgart, jahrgang 1969, heft 2, p. 104-120. hurka, h. & schmid, r. (1971): diplopora prae cursor , a mesozoic calcareous alga (dasycladaceae) with endospore cysts.nova hedwigia, lehre, band xxi, heft 1-4, p. 505-519, 2 pl. (1-2). iannace, a. (1991, inédit): ambienti deposizionali e processi diagenetici in successioni di piattaforma carbonatica del trias superiore nei monti lattari e picentini (salerno).tesi di dottorato, università degli studi di napoli federico ii, 221p. iannace, a., boni, m. & zamparelli, v. (1995): the middle-upper triassic of the san donato unit auct. (northern calabria): stratigraphy, paleogeography and tectonic implications.rivista italiana di paleontologia e stratigrafia, milano, vol. 101, n° 3, p. 301-324. iannace, a., r a d o i » i ∆ , r. & zamparelli, v. (1998): a new dasycladalean alga from the middle triassic carbonates of northern calabria (southern italy).facies, erlangen, 39, p. 67-74, 2 pl. (12-13). ishijima, w. (1975): on some permian algae from the takagami conglomerate, chôshi, chiba prefecture.st. paul’s review of science, rikkyo, vol. 3, n° 4, p. 119-128, 3 pl. h.-t. (1-3). ishijima, w., ozaki, h. & nakamura, m. (1971): upper paleozoic calcareous algae from the limestone at sakaishimachibun, saitama-ken.bulletin of the national science museum, tokyo, vol. 14, n° 1, p. 97-136, 16 pl. h.-t. (1-16). istocescu, d. & dragastan, o. (1978): l e s occurences triasiques du bassin de beius (monts apuseni).dǎri de seamǎ ale ş e d i nţelor, bucureş t i , 4. stratigrafie, vol. lxiv (1976-1977), p. 137-145, 5 pl. h.-t. (i-v). jenny-deshusses, c. (1983, i n é d i t): le permien de l’elbourz central et oriental (iran): stratigraphie et micropaléontologie (foraminifères et algues).thèse doctorat ès sciences, université de genève, n° 2103, genève, 214 p., 25 pl. h.-t. (1-25). jodot, p. (1930): sur l’existence du dinantien au col san colombano (corse) et sur les conséquences tectoniques possibles de cette découverte.bulletin de la société géologique de france, paris, 4° série, t. xxx, n° 6, p. 515-562, 2 pl. h.-t. (l-li). johnson, j.h. (1942): permian lime-secreting algae from the guadalupe mountains, new-mexico.bulletin of the geological society of america, boulder, vol. 53, p. 195-226, 7 pl. h.-t. (1-7). johnson, j.h. (1943): geological importance of calcareous algae with annotated bibliography.quarterly of the colorado school of mines, golden, vol. 38, n° 1, 102 p. johnson, j.h. (1944): calcareous algae.in: s h imer, h.w. & shrock, r.r. (eds.): index fossils of north america. john wiley & sons, new york, p. 715-716, 1 pl. h.-t. (302). johnson, j.h. (1945): calcareous algae as useful microfossils.journal of paleontology, tulsa, vol. 19, n° 4, p. 350-354, 2 pl. h.-t. (52-53). 177granier & grgasoviê: les algues dasycladales du permien et du trias... johnson, j.h. (1946a): late paleozoic algae of north america.the american midland naturalist, notre dame, vol. 16, n° 2, p. 264-274, 2 pl. (1-2). johnson, j.h. (1946b): lime-secreting algae from the pennsylvanian and permian of kansas.bulletin of the geological society of america, boulder, vol. 57, p. 1087-1120, 10 pl. h.-t. (1-10). johnson, j.h. (1951): permian calcareous algae from the apache mountains, texas.journal of paleontology, tulsa, vol. 25, n° 1, p. 21-30, 5 pl. h.-t. (610). johnson, j.h. (1954): an introduction to the study of rock building algae and algal limestones.quarterly of the colorado school of mines, golden, vol. 49, n° 2, 117 p., 62 pl. (1-62). johnson, j.h. (1961): limestone-building algae and algal limestones.colorado school of mines, golden, 297 p., 139 pl. (1-139). johnson, j.h. (1963): pennsylvanian and permian algae.quarterly of the colorado school of mines, golden, vol. 58, n° 3, 211 p., 81 pl. (1-81). johnson, j.h. (1966): new mississipian algae from alberta. paleontological notes.journal of paleontology, tulsa, vol. 40, n° 6, p. 1385-1387, 1 pl. h.-t. (176). johnson, j.h. (1969): a review of the lower cretaceous algae.professional contributions of the colorado school of mines, golden, 6, 180 p., 68 pl. (168). johnson, j.h. & danner, w.r. (1966): p e r m i a n calcareous algae from northwestern washington and southwestern british columbia.journal of paleontology, tulsa, vol. 40, n° 2, p. 424-432, 2 pl. h.-t. (55-56). johnson, j.h. & dorr, m.e. (1942): the permian algal genus mizzia.journal of paleontology, tulsa, vol. 16, n° 1, p. 63-77, 4 pl. h.-t. (9-12). johnson, j.h. & kaska, h.v. (1965): fossil algae from guatemala.professional contributions of the colorado school of mines, golden, n° 1, 152 p., 47 pl. (1-47). johnson, j.h. & konishi, k. (1956): part i. a review of mississipian algae.in: johnson, j.h. & konishi, k. (eds.): studies of mississipian algae. quarterly of colorado school of mines, golden, vol. 51, n° 4, p. 1-84, 24 pl. (1-24). jones, d.j. (1956): introduction to microfossils.harper & brothers, new york, 406 p. kahler, f. & krainer, k. (1993): the schulterkofel section in the carnic alps, austria: implications for the carboniferous-permian boundary.facies, erlangen, 28, p. 257-276, 5 pl. (66-70). kalantari, a. (1986): microfacies of carbonate rocks of iran.ministry of oil, national iranian oil company, tehran, 287 p., 135 pl. (1-135) + 233 p., 101 pl. (1-101). kamptner, e. (1948): a. gyroporella verticillata nov. spec., eine neue dasycladacee aus der obertrias des lunzberg-stollens bei lunz (niederösterreich).in: trauth, f. (ed.): geologie des kalkalpenbereiches der zweiten wiener hochquellenleitung. abhandlungen der geologischen bundesanstalt in wien, band xxvi, heft 1, p. 79-82, 1 pl. h.-t. (xi). karpinsky, a. (1909a): o nykotorykh’ problematicheskikh” organicheskikh’ ostatkakh’ japonii.izvestija imperatorskoj akademii nauk’ [bulletin de l’académie impériale des sciences de st.-pétersbourg], n° 15, p. 1045-1056, 1 pl. h.-t. karpinsky, a. (1909b): ix. einige problematischen fossilien aus japan.zap. imp. miner. obshch., t. xlvi, p. 257-272, 1 pl. h.-t. (iii). karrer, f. (1877): geologie der kaiser franz josefs hochquellen-wasserleitung. eine studie in den tertiär-bildungen am westrande des alpinen theiles der niederung von wien.herausgegeben von der kaiserlich-königlichen geologischen reichsanstalt, wien, band ix, 420 p., 20 pl. h.-t. khvorova, i.v. (1949): novyj rod mutovchatykh sifonej iz srednego karbona moskovskoj sineklizy.doklady akademii nauk sssr, moskva, t. lxv, n° 5, p. 749-752. kirkland, b.l. (1995): distribution of dasycladacean algae in the permian capitan formation and carlsbad group, guadalupe mountains, texas and new mexico, u.s.a.in: piller, w.e. (ed.): proceedings of the international symposium and fieldmeeting “alpine algae ‘93”. beiträge zur paläontologie, wien, n° 19 (1994), p. 153-159, 1 pl. (1). kirkland, b.l. & chapman, r.l. (1990): t h e fossil green alga m i z z i a (dasycladaceae): a tool for interpretation of paleoenvironment in the upper permian capitan reef complex, southeastern new mexico.journal of phycology, baltimore, 26, p. 569-576. kiss, j. (1958): ércföldtani vizsgálatok a siroki darnóhegyen.földtani-közlöny, budapest, t. lxxxviii, n° 1, p. 27-41, 6 pl. h.-t. (i-vi). kobel, m. (1969): lithostratigraphische und sedimentologische untersuchungen in der kalkalpinen mitteltrias (anisian und ladinian) des rätikon (österreich und fürstentum liechtenstein).mitteilungen aus dem geologischen institut der eidgenössischen technischen hochschule und der universität zürich, n.f. 118, 149 p. kochansky, v. & herak, m. (1960): on the carboniferous and permian dasycladaceae of yugosla178 geologia croatica 53/1 via [o karbonskim i permskim dasikladacejama j u g o s l a v i j e].geoloπki vjesnik, zagreb, svezak xiii (1959), p. 65-94, 9 pl. h.-t. (i-ix). k o c h a n s k y d e v i d é, v. (1964a): v e l e b i t e l l a, eine neue jungpaläozoische diploporeengattung und ihre phylogenetischen verhältnisse [v e l e b i t e l l a, novi gornjopaleozojski rod diploporea i njeni filogenetski odnosi].geoloπki vjesnik, zagreb, svezak 17 (1963), p. 135-142, 4 pl. h.-t. (i-iv). kochansky-devidé, v. (1964b): die mikrofossilien des jugoslawischen perms.paläontologische zeitschrift, stuttgart, vol. 38, n˚ 3/4, p. 180-188, 2 pl. h.-t. (18-19). k o c h a n s k y d e v i d é, v. (1967): eine interessante neue p h y s o p o r e l l a -art (dasycladaceae) aus der trias von slowenien [interesantna nova vrsta roda p h y s o p o r e l l a (dasycladaceae) iz trijasa slovenije]. geoloπki vjesnik, zagreb, svezak 20 (1966), p. 171174, 1 pl. h.-t. (i). k o c h a n s k y d e v i d é, v. (1970a): permski mikrofosili zahodnih karavank [permische mikrofossilien der westkarawanken].geologija razprave in poroëila, ljubljana, knjiga 13, p. 175-256, 26 pl. h.t. (i-xxvi). k o c h a n s k y d e v i d é, v. (1970b): die kalkalgen des karbons vom velebit-gebirge (moskovien und kassimovien) [vapnenaëke alge karbona velebita (moskovijen i kasimovijien)].palaeontologia jugoslavica, zagreb, sv. 10, p. 1-32, 15 pl. h.-t. (ixv). k o c h a n s k y d e v i d é, v. (1979): connexia slove n i c a n. sp., eine leitende art der trogkofel-ablagerungen (perm) [connexia slovenica n. sp., znaëajna vrsta trogkofelskih naslaga (perm)].palaeontologia jugoslavica, zagreb, sv. 23, p. 1-10, 2 pl. h.-t. (i-ii). kochansky-devidé, v., buser, s., cajhen, j. & r a m o v © , a. (1973): podroben profil skrozi trogkofelske plasti v potoku koπutnik v karavankah [detaillertes profil durch die trogkofel-schichten am koπutnik-bach in der karawanken].razprave [d i s s e r t a t i o n e s], slovenska akademija znanosti in umetnosti, razred za prirodoslovne in medicinske vede, ljubljana, vol. xvi, n° 4, p. 171-187, 5 pl. h.-t. (1-5). k o c h a n s k y d e v i d é, v. & m i l a n o v i ∆ , m . (1962): donjopermske fuzulinide i vapnenaëke alge produëja tare u crnoj gori [unterpermische fusuliniden und kalkalgen des tara-gebiets in der mittleren crna gora (montenegro)].geoloπki vjesnik, zagreb, svezak 15 (1961), broj 1, p. 195-228, 8 pl. h.-t. (i-viii). k o c h a n s k y d e v i d é, v. & r a m o v © , a. (1955): neoschwagerinski skladi in njih fuzulinidna favna pri bohinjski beli in bledu [die neoschwagerinenschischten und ihre fusulinidenfauna bei bohinjska bela und bled (julische alpen, slowenien, jugoslaw i e n )].razprave [d i s s e r t a t i o n e s], slovenska akademija znanosti in umetnosti, razred za prirodoslovne vede, ljubljana, vol. iii, p. 359-424, 8 pl. h.t. (i-viii). k o c h a n s k y d e v i d é, v. & r a m o v © , a. (1965): razvoj mlajπega paleozoika v okolici ortneka na dolenjskem.razprave [d i s s e r t a t i o n e s], slovenska akademija znanosti in umetnosti, ljubljana, vol. viii, p. 319-416, 18 pl. h.-t. (i-xviii). k o c h a n s k y d e v i d é, v. & r a m o v © , a. (1966): zgornjekarbonski mikrofosili in stratigrafski razvoj v zahodnih karavankah [oberkarbonische mikrofossilien und stratigraphische entwicklung in den w e s t k a r a w a n k e n].razprave [d i s s e r t a t i o n e s], slovenska akademija znanosti in umetnosti, ljubljana, vol. ix, n° 7, p. 299-333, 11 pl. h.-t. (i-xi). k o c h a n s k y d e v i d é, v. & s l i © k o v i ∆ , t . (1969): gornjopermski mikrofosili han orahovice i ©uljaca u bosni s osobitim obzirom na algu permo calculus fragilis [ober permische mikrofossilien von han orahovica und ©uljci in bosnien mit besonder berücksichtigung der alge permocalculus f r a g i l i s].geoloπki vjesnik, zagreb, svezak 22 (1968), p. 105-110, 2 pl. h.-t. (i-ii). kodra, b. (1972): disa tè dhèna stratigrafike pèr prerjen e prozhmès (kollatès) tè rajonit tè valbonès.pèrmbledhje studimesh, tiranè, 4, p. 5-25, 4 pl. (14). kollárová-andrusovová, v. & bystric ký, j. (1974): übersicht über den gegenwärtigen stand der biostratigraphie der trias der westkarpaten.in: zapfe, h. (ed.): die stratigraphie der alpin-mediterranen trias [the stratigraphy of the alpine-mediterranean triassic], symposium (wien, 1973). österreichische akademie der wissenschaften, schriftenreihe der erdwissenschaftlichen kommissionen, band 2, springer-verlag, wien new york, p. 125-136. konishi, k. (1952): 212. permian microfossils in the dodo conglomerate of the yasuba-type.transactions and proceedings of the palaeontological society of japan, tokyo, new series, n° 5, p. 155-165, 1 pl. h.-t. (14). konishi, k. (1953): 241. new boultonia and other microfossils from north thailand (siam).transactions and proceedings of the palaeontological society of japan, tokyo, new series, n° 12, p. 103-111, 1 pl. h.-t. (11). konishi, k. (1954a): 1. a new species of g y m n o c o d i u m and its algal associates in the permian kosaki formation of southern kyushu, japan (studies on the paleozoic marine algae of japan 1).japanese journal of geology and geography, tokyo, vol. xxv, n° 1-2, p. 1-19, 2 pl. h.-t. (i-ii). 179granier & grgasoviê: les algues dasycladales du permien et du trias... konishi, k. (1954b): s u c c o d i u m, a new codiacean genus, and its algal associates in the late permian kuma formation of southern kyushu, japan (studies on the paleozoic marine algae of japan 2).journal of the faculty of science, university of tokyo, sect. ii, vol. ix, part ii, p. 225-240, 2 pl. h.t. (i-ii). konishi, k. (1956): part iii. a n a t o l i p o r a , a new dasycladacean genus, and its algal associates from the lower carboniferous of japan.in: j o h n s o n , j.h. & konishi, k. (eds.): studies of mississipian algae. quarterly of colorado school of mines, golden, vol. 51, n° 4, p. 109-127. konishi, k. (1959): notes of some japnaese permian and cretaceous algae and their stratigraphic setting (studies of the paleozoic marine algae of japan. 4).journal of the faculty of science, university of tokyo, section ii, vol. xi, part 4, p. 441-456, 3 pl. h.-t. (xxix-xxxi). k o r d é, k.b. (1950): k morfologii mutvchatykh sifonej karbona severnogo urala.doklady akademii nauk sssr, moskva, tom 73, n° 3, p. 569-571. kordé, k.b. (1951): novye rody i vidy izvestkovykh vodoroslej iz kamennougol’nykh otlozhenij severnogo urala.trudy moskovskoye obshchestva ispytateley prirody, otdel geologicheskiy, moskva, tom 1, p. 175-182, 3 pl. h.-t. (i-iii). k o r d é, k.b. (1965): algae.in: razvitie i smena morskikh organizmov na rubezhe paleozoja i mezozoja. trudy paleontologicheskogo instituta, akademija nauk sssr, moskva, tom 108, p. 268-284, 8 pl. h.-t. (li-lviii). k o t ański, z. (1963): stratygrafia i litologia triasu regli zakopiańskich [stratigraphie et lithologie du trias subtatrique de la région de zakopane].acta geologica polonica, warszawa, vol. xiii, n° 3-4, p. 317-385, 6 pl. h.-t. (i-vi). k o t ańs k i, z. (1973): upper and middle subtatric nappes in the tatra mts.bulletin de l’académie polonaise des sciences, warszawa, série des sciences de la terre, vol. xxi, n° 1, p. 75-83, 6 pl. h.t. (i-vi). kotański, z. (1979): in: gaździcki, a., fugelwicz, r., karczewski, l., kotańs k i, z., marcinkiewicz, t., morycowa, e., orlowska-zwolinska, t., piotrowski, a., reymanowna, m., roniewich, e., senkowiczowa, h., styk, o., trammer, j. & zawidzka, k.: budowa geologiczna polski. tom iii. atlas skamienialosci przewodnich i charakterystycnych. czesc 2a. mezozoik. trias. instytut geologiczny, wydawnictwa geologiczne, warszawa, p. 218-222, 2 pl. h.-t. (79-80). k o t ańs k i, z. (1986): macroflora. class chlorophyta.in: gaźd z i c k i, a., fugelwicz, r., karczewski, l., kotańs k i, z., m a r c i n k i e w icz, t., morycowa, e., orlowska-zwolinska, t., piotrowski, a., reymanowna, m., roniewich, e., senkowiczowa, h., styk, o., trammer j. & zawidzka, k.: geology of poland. volume iii. atlas of guide and characteristic fossils. part 2a. mesozoic. triassic. instytut geologiczny, wydawnictwa geologiczne, warszawa, p. 176-184 & 218-220, 4 pl. h.-t. (ciiicvi). k o t ański, z. & »atalov, g.a. (1973): triassic dasycladaceae from central balkan and fore-balkan, bulgaria.acta palaeontologica polonica, warszawa, vol. xviii, n° 2, p. 187-210, 8 pl. h.-t. (vixiii). köylüoglu, m. & altiner, d. (1989): micropaléontologie (foraminifères) et biostratigraphie du permien supérieur de la région d’hakkâri (se turquie).revue de paléobiologie, genève, vol. 8, n° 2, p. 467-503, 6 pl. (i-vi). krainer, k. (1991): the limestone facies of the auernig and carnizza formations (auernig group, pontebba supergroup; carnic alps).giornale di geologia, bologna, ser. 3a, vol. 53/1, p. 161-169. krainer, k. (1992): fazies, sedimentationsprozesse und paläogeographie im karbon der ostund südalpen.in: neuergebnisse aus dem paläozoikum der ostund südalpen. jahrbuch der geologischen bundesanstalt, wien, band 135, heft 1, p. 99-193, 7 pl. h.-t. (1-7). krainer, k. (1995): a n t h r a c o p o r e l l a mounds in the late carboniferous auernig group, carnic alps (austria).facies, erlangen, 32, p. 195-214, 4 pl. (38-41). kubanek, f. (1969, inédit): sedimentologie des alpinen muschelkalks (mitteltrias) am kalkalpensüdrand zwischen kufstein (tirol) und saalfelden (salzburg).dissertation, doktor der naturwissenschaften, d 83, technischen universität berlin, 202 p. kulik, e.l. (1964): berezellidy karbona russkoj platformy [bereselleae from the carboniferous of the russian platform].paleontologicheskij zhurnal [palaeontological journal], moskva, n° 2, p. 99114, 1 pl. h.-t. (viii). kulik, e.l. (1978): izvestkovye zelenye (sifonovye) vodorosli asselskogo i sakmarskogo jarusov biogermnogo massiva shakhtau (bashkirija) [c a l c a r e o u s green (siphonal) algae of the asselian and sakmarian stages of the shakhtau bioherm massif (bashk i r i a )].akademija nauk sssr, otdelenie geologii, geofiziki i geokhimii, voprosy mikropaleontologii, vynusk 21, p. 182-215 & 234-235, 8 pl. h.-t. (iviii). lakew, t. (1990): microfacies and cyclic sedimentation of the upper triassic (rhaetian) calcare di zu 180 geologia croatica 53/1 (southern alps).facies, erlangen, 22, p. 187-232, 13 pl. (39-51). lamouroux, j.v. (1816): histoire des polypiers coralligènes flexibles, vulgairement nommés zoophytes.poisson, caen, 559 p., 19 pl. lemoine, m. (1954): chapitre ii. étude des algues calcaires et de leur répartition.in: fallot, p., solé sabaris, l. & lemoine, m., observations sur le trias bétique et ses algues calcaires. memorias y communicaciones del instituto geologico provincial, barcelona, tomo xi, p. 23-60 (p. 39-60), 5 pl. h.-t. (i-v). l e o n a r d i , p. (1967): capitolo xix. le scogliere organogene delle dolomiti.in: leonardi, p . (ed.): le dolomiti. geologia dei monti tra isarco e piave. consiglio nazionale delle ricerche e della giunta provinciale di trento, vol. 1, p. 215-260, 1 pl. (xxxii). lys, m. (1988a): biostratigraphie des dépôts marins du carbonifère et du permien du sud-tunisien micropaléontologie (foraminifères) et paléobiogéographie.bulletin des centres de recherches exploration-production elf-aquitaine, pau, vol. 12, n° 2, p. 601-659, 12 pl. (1-12). lys, m. (1988b): biostratigraphie du carbonifère et du permien en mésogée (espagne, afrique du nord, régions égéennes, proche-orient). études micropaléontologiques (foraminifères). paléobiogéographie.thèse de doctorat d’etat, université de parissud, orsay, documents du b.r.g.m., orléans, n° 147, 315 p., 21 pl. (i-xxi). lys, m., colchen, c., bassoullet, j.-p., marcoux, j. & mascle, g. (1980): la biozone à coloniella parva du permien supérieur et sa microfaune dans le bloc calcaire exotique de lamayuru, himalaya du ladakh.revue de micropaléontologie, paris, vol. 23, n° 2, p. 76-108, 7 pl. (1-7). lys, m. & lapparent, a.f. d e (1971): f o r a m i n ifères et microfaciès du permien de l’afghanistan central.notes et mémoires sur le moyen-orient, paris, tome xii, 1è r e partie, p. 47-133, 16 pl. h.-t. (vii-xxii). lys, m. & serre, b. (1958): contribution à la connaissance des microfaunes du paléozoïque. études micropaléontologiques dans le carbonifère marin des asturies (espagne).revue de l’institut français du pétrole, paris, vol. xiii, n° 6, p. 879-916, 11 pl. (i-xi). lys, m., stampfli, g. & jenny, j. (1978): b i o stratigraphie du carbonifère et du permien de l’elbourz oriental (iran du ne).notes du laboratoire de paléontologie de l’université de genève, fasc. 2, n° 1-13 (note n° 10), p. 63-99, 8 pl. (1-8). mahel’, m. (1958): geologie des gebirges stratenská hornatina.geologické práce, bratislava, zoπit 48b (1957), 176 p., 25 pl. h.-t. (i-xxv). makhaev, v.n. (1937): vodorosli kak rukovdjashie iskopaemye [les algues comme fossiles caractérist i q u e s].doklady akademii nauk sssr [c o m p t e s rendus de l’académie des sciences de l’urss], moskva, tom xv, n° 8, p. 483-486. makhaev, v.n. (1940): materialy k poznaniju iskopaemykh vodoroslej sssr.bjulleten moskovskoye obshchestva ispytateley prirody, otdel geologicheskiy [bulletin soc. nat. moscou, s. géologi que], moskva, t. xviii (5-6), p. 61-73, 2 pl. h.-t. (iii). mamet, b. (1991): chapter 19. carboniferous calcareous algae.in: riding, r. (ed.): calcareous algae and stromatolites. springer-verlag, berlin, p. 370-451, 3 pl. (i-iii). mamet, b. (1996): algues calcaires marines du paléozoïque supérieur (équateur, bolivie).annales de la société géologique de belgique, liège, tome 117 (1994), fasc. 1, p. 155-167, 3 pl. (1-3). mamet, b., nassichuk, w.w. & roux, a. (1979): algues et stratigraphie du paléozoïque supérieur de l’arctique canadien.in: 2è m e s y m p o s i u m international sur les algues fossiles (paris, 23-26 avril 1979). bulletin des centres de recherches exploration-production elf-aquitaine, pau, vol. 3, n° 2, p. 669-683, 3 pl. (1-3). mamet, b. & roux, a. (1975a): d a s y c l a d a c é e s dévoniennes et carbonifères de la téthys occidentale.revista española de micropaleontologia, madrid, vol. vii, n° 2, p. 245-295, 13 pl. (i-xiii). mamet, b. & roux, a. (1975b): jansaella ridingi , nouveau genre d’algue? dans le dévonien de l’alberta.canadian journal of earth sciences, ottawa, vol. 12, p. 1480-1484. mamet, b. & roux, a. (1978a): sur l’attribution de thalles algaires carbonifères et permiens aux éponges hypercalcifiées.revue de micropaléontologie, paris, vol. 21, n° 1, p. 19-27, 1 pl. (1). mamet, b. & roux, a. (1978b): algues viséennes et namuriennes du tennessee (états-unis).revue de micropaléontologie, paris, vol. 21, n° 2, p. 6897, 7 pl. (1-7). mamet, b. & roux, a. (1982): sur la présence de m i c r o c o d i u m (algue ?, incertae sedis ?) dans le paléozoïque supérieur de l’arctique canadien.canadian journal of earth sciences, ottawa, vol. 19, n° 2, p. 357-363, 2 pl. (1-2). mamet, b. & roux, a. (1983): algues dévono-carbonifères de l’australie.revue de micropaléontologie, paris, vol. 26, n° 2, p. 63-131, 16 pl. (1-16). 181granier & grgasoviê: les algues dasycladales du permien et du trias... mamet, b., roux, a. & nassichuk, w.w. (1987): algues carbonifères et permiennes de l’arctique canadien.geological survey of canada, bulletin, ottawa, 342, 143 p., 30 pl. (1-30). mamet, b. & rudloff, b. (1973): algues carbonifères de la partie septentrionale de l’amérique du nord.revue de micropaléontologie, paris, vol. 15, n° 2, p. 75-114, 10 pl. (1-10). mamet, b. & villa, e. (1995): a revision of the dasycladale alga uraloporella (chlorophyta, upper paleozoic, asturias, spain).revista española de paleontología, madrid, n° homenaje al dr. guillermo colom, p. 48-54, 1 pl. (i). marinos, g. & reichel, m. (1958): the fossiliferous permian in eastern continental greece and euboea.in: the geology of greece, athens, n° 8, 16 p., 3 pl. h.-t. (i-iii). marschalko, r., m i © í k , m. & kamenický, l. (1976): petrographie der flysch-konglomerate und rekonstruktion ihrer ursprungszonen (paläogen der klippenzone und der angrenzenden tektonischen einheiten der ostslowakei).západné karpaty, bratislava, séria geológia 1, p. 7-124, 41 pl. h.-t. (ixli). m a r t í n, j.m. & braga, j.c. (1989): u p p e r t r i a ssic algal bioconstructions in the alpujárride complex (betic cordillera, s. spain).in: braga, j.c. & martín, j.m. (eds.): algae in reefs. field trip guidebook, universidad de granada, p. 1-25, 2 pl. (1-2). m a r t í n, j.m. & delgado, f. (1980): b i o s t r o m e s of dasycladacean algae and stromatolites: a peculiar interbedding.sedimentary geology, amsterdam, vol. 25, p. 117-126. masaryk, p. (1988): mikrofaciálna charakteristika t r i a s o vých sekvencií vyππích príkrovov bieleho pohoria malých karpát a ich korelácia s podloæím viedenskej panvy.miscellanea micropalaeontologica, ii/1, sborník prací věn o v a ný, 4. »eskoslovenskému mikropaleontologickému semináři [4 t h czechoslovak micropaleontological colloquium], hodonín (1987), p. 153-189, 5 pl. (1-5). maslov, v.p. (1956): iskopaemye izvestkovye vodorosli sssr.trudy instituta geologicheskikh nauk, akademija nauk sssr, moskva, vypusk 160, 297 p., 86 pl. h.-t. (i-lxxxvi) [les algues calcaires fossiles de l’u.r.s.s.traduction b.r.g.m. n° 3517: 1er livre, p. 1-158; 2ème livre, p. 159-234; 3ème livre: p. 235-382]. maslov, v.p. (1963): tip chlorophyta. zelenye v o d o r o s l i . i n : vakhrameeba, v.a., radchenko, g.p. & takhmadzhana, a.l. ( e d s . ) : osnovy paleontologii. spravochnik ilja paleontologov i geologov sssr. izdatel’stvo akademii nauk sssr, moskva, p. 198-223, 5 pl. h.-t. (xiv-xviii). maslov, v.p. & kulik, e.l. (1956): novaja triba vodoroslej (b e r e s e l l e a e) iz karbona sssr.doklady akademii nauk sssr, moskva, tom 106, n° 1, p. 126-129. mégard-galli, j. (1968): étude stratigraphique et tectonique du monte boulliagna (haut val d’acceglio, italie).géologie alpine, grenoble, tome 44, p. 281-322. mello, j. (1974): facial development and facial relations of the slovak karst middle and upper triassic (west carpathians, southern part of gemerids).in: zapfe, h. (ed.): die stratigraphie der alpin-mediterranen trias [the stratigraphy of the alpinemediterranean triassic], symposium (wien, 1973). österreichische akademie der wissenschaften, schriftenreihe der erdwissenschaftlichen kommissionen, band 2, springer-verlag, wien new york, p. 147-155, 2 pl. h.-t. (i-ii). mello, j. (1975): triassische biohermkalke im östlichen teil des slowakischen karstes.geologický zborník geologica carpathica, bratislava, vol. xxvi, n° 1, p. 21-46, 8 pl. (i-viii). merciai, g. (1908): fossili dei calcari grigio-scuri di monte malbe presso perugia.atti della società toscana di scienze naturali, pisa, vol. xxiv, p. 218246, 1 pl. h.-t. (vii). michard, a. (1962a): description de teutloporelles et de gyroporelles dans le ladinien du val grana (alpes cottiennes internes, italie).bulletin de la société géologique de france, paris, 7° série, t. iv, p. 79-82, 1 pl. h.-t. (iv). michard, a. (1962b): premières données paléontologiques et stratigraphiques sur le trias du massif maira-grana (alpes cottiennes méridionales).bol lettino della società geologica italiana, roma, vol. lxxx, fasc. 4, p. 31-101, 14 pl. (i-xiv). michard, a. (1967): études géologiques dans les zones internes des alpes cottiennes.thèse de doctorat d’etat (7 juin 1966), editions du c.n.r.s., paris, 447 p., 28 pl. (i-xxviii). michelin, h. (1840-1847): iconographie zoophytologique. description par localités et terrains des polypiers fossiles de france et pays environnants.p. bertrand, paris, 348 p., 79 pl. h.-t. (1-79). milanovi∆, m. (1965a): salopekiella, novi rod familije dasycladaceae iz permskih sedimenata velebita [s a l o p e k i e l l a, a new genus of the dasycladaceae family from the permian sediments of the velebit r a n g e].acta geologica (prirodoslovna istraæivanja jugoslavenske akademije znanosti i umjetnosti, 35), zagreb, vol. v, p. 373-382, 3 pl. h.-t. (i-iii). m i l a n o v i ∆, m. (1965b): zwei neue gattungen der familie dasycladaceae aus dem perm velebitgebirges.bulletin scientifique, conseil des académi182 geologia croatica 53/1 es des sciences et des arts de la r.s.f. de yougoslavie, section a: sciences naturelles, techniques et médicales, zagreb, tome 10, n° 6, p. 179-180. m i l a n o v i ∆, m. (1966a): l i k a n e l l a a new permian genus of the family dasycladaceae [likanella novi permski rod familije dasycladaceae].geoloπki vjesnik, zagreb, svezak 19 (1965), p. 9-14, 4 pl. h.-t. (i-iv). m i l a n o v i ∆, m. (1966b): g o n i o l i n o p s i s, a new permian genus of the family dasycladaceae [g o n i o l i n o p s i s, novi permski rod familije dasycladaceae]. geoloπki vjesnik, zagreb, svezak 19 (1965), p. 115122, 3 pl. h.-t. (i-iii). milanovi∆, m. (1968): salopekiella ? kochanskae n. sp. (dasycladaceae) from the permian of the velebit mountain [salopekiella ? k o c h a n s k a e n. sp. (dasycladaceae) iz perma velebita].geoloπki vjesnik, zagreb, svezak 21 (1967), p. 157-160, 4 pl. h-t. (iiv). m i l a n o v i ∆, m. (1974): k o c h a n s k y e l l a ( c h l o r o p h yta, dasycladaceae), a new permian genus of mount velebit, croatia [k o c h a n s k y e l l a (chlorophyta, dasycladaceae) iz perma velebita].geoloπki vjesnik, zagreb, svezak 27, p. 127-132, 5 pl. h.-t. (i-v). m i l a n o v i ∆, m. (1975): salopekiella ? b r e z i k i n. sp. (calcareous algae, dasycladaceae) from the permian of mt. velebit (croatia) [salopekiella ? b r e z i k i n . sp., (vapnenaëke alge, dasycladaceae) iz perma v e l e b i t a].geoloπki vjesnik, zagreb, svezak 28, p. 81-86, 3 pl. h-t. (i-iii). m i l a n o v i ∆, m. (1982): carboniferous microfossil associations from gorski kotar, hrvatsko zagorje and banija [karbonske mikrofosilne asocijacije gorskog kotara, hrvatskog zagorja i banije]. palaeontologia jugoslavica, zagreb, svezak 28, p. 134, 10 pl. h.-t. (i-x). milanovi∆, m. (1986): permski mikrofosili gorskog kotara.xi kongres geologa jugoslavije, tara, knjiga 2, p. 91-98, 4 pl. h.-t. (i-iv). mirkovi∆, b. (1974): prilog poznavanju razviêa perma u istoënoj crnoj gori [contribution à la connaissance du développement de permien dans le monténégro de l’est].geoloπki glasnik [bulletin géolog i q u e], titograd (podgorica), knjiga [l i v r e] vii, p. 147-156, 12 pl. h.-t. (i-xii). m i r k o vi ∆, b. (1986): mikrofacije perma nikπiêke æupe sa osvrtom na biostratigrafske paleoekoloπke karakteristike [permian microfacies from niksicka zupa with the review to the biostratigraphic paleoecologic characteristics].geoloπki glasnik [b u lletin géologique], titograd (podgorica), knjiga [l ivre] xi, p. 31-48, 14 pl. h.-t. (i-xiv). m i © í k, m. (1966): microfacies of the mesozoic and tertiary limestones of the west carpathians [mikrofácie vápencov mezozoika a terciéru západnýc h k a r p á t].slovenska akadémia vied, bratislava, 269 p., 101 pl. (i-ci). m i © í k, m. (1972): lithologische und fazielle analyse der mittleren trias der kerngebirge der westkarpaten.acta geologica et geographica universitatis comenianae, geologica, bratislava, n° 22, p. 5154, 64 pl. h.-t. (i-lxiv). m i © í k, m. (1987): the alga halicoryne carpatica n . sp. from upper triassic of western carpathians.g e o l o g i c ký zborník geologica carpathica, bratislava, vol. 38, n° 3, p. 285-293, 2 pl. (i-ii). m i © í k, m. & borza, k. (1976): obere trias bei silická brezová (westkarpaten).acta geologica et geographica universitatis comenianae, geologica, bratislava, n° 30, p. 5-49, 22 pl. h.-t. (i-xxii). m i © í k, m., mock, r. & sýkora, m. (1977): d i e trias der klippenzone der karpaten.geologický zborník geologica carpathica, bratislava, vol. 28, n° 1, p. 27-69, 8 pl. (i-viii). morellet, l. & morellet, j. (1913): les dasycladacées du tertiaire parisien.mémoires de la société géologique de france, paléontologie, paris, t. xxi, fasc. 1, n° 47, 43 p., 3 pl. h.-t. (i-iii). montanari, l. (1965): geologia del monte pellegrino (palermo).rivista mineraria siciliana, palermo, anno xv (1964), n° 88-90, anno xvi (1965), n° 91-93, p. 3-64. montenat, c., lapparent, a.f., lys, m., termier, h., termier, g. & vachard, d. (1976): la transgression permienne et son substratum dans le jebel akhdar (montagnes d’oman, péninsule arabique).société géologique du nord, annales, villeneuve d’ascq, t. xcvi, 3è m e t r i m estre, p. 239-258, 7 pl. h.-t. (xvii-xxiii). mu, x.-n. (1974): 11. algae.in: nanking institute of geology and paleontology: a handbook of the stratigraphy and paleontology in southwest china. science press, academia sinica, beijing, p. 315317, 1 pl. h.-t. (167). mu, x.-n. (1981): upper permian calcareous algae from western guizhou.acta palaeontologica sinica, beijing, vol. 20, n° 1, p. 33-48, 4 pl. h.-t. (i-iv). mu, x.-n. (1982): some calcareous algae from xizang.in: palaeontology of xizang. the series of the scientific expedition to the qinghai-xizang plateau. science press, beijing, book v, p. 205-240, 12 pl. h.-t. (i-xii). mu, x.-n. (1984): a new permian dasycladales (calcareous alga) from xizang, with a discussion on the genus g o n i o l i n o p s i s.acta micropalaeontologica sinica, beijing, vol. 1, n° 1, p. 61-71, 1 pl. h.-t. (i). mu, x.-n. & elliott, g.f. (1982): n a n j i n o p o r e l l a , a new permian dasyclad (calcareous alga) from 183granier & grgasoviê: les algues dasycladales du permien et du trias... nanjing, china.bulletin of the british museum (natural history), geology, london, vol. 36, n° 2, p. 109-116. munier-chalmas, e.p. (1877): observations sur les algues calcaires appartenant au groupe des siphonées verticillées (dasycladées harv.) et confondues avec les foraminifères.compte rendu de l’académie des sciences, paris, t. lxxxv, n° 18, p. 814-817. nakamura, m. (1981): fossil algae from the ishiyama limestone, gifu prefecture.national science museum, bulletin, tokyo, series c (geology & paleontology), vol. 7, n° 2, p. 27-60, 10 pl. (1-10). nakamura, m. & chisaka, t. (1984): f o s s i l algae from the takagami conglomerate, choshi-shi, chiba prefecture.national science museum, bulletin, tokyo, ser. c, vol. 10, n° 3, p. 87-121, 11 pl. (1-11). négris, p. (1915): roches cristallophyliennes et tectonique de la grèce. + appendice.athènes, 207 p., 25 pl. h.-t. (i-xxv). négris, p. (1919): roches cristallophyliennes et tectonique de la grèce. 2è m e appendice.athènes, 207 p., 22 pl. h.-t. (xxvi-xlvii). n g u yên, d.t. (1979, i n é d i t): étude micropaléontologique (foraminifères) de matériaux du permien du cambodge.thèse, doctorat 3° cycle, université de paris sud, orsay, 166 p., 32 pl. h.-t. (1-32). n g u yên, d.t. (1986a): appendix 2 foraminifera and algae from the permian of kampuchea.c.c.o.p. technical bulletin, bangkok, vol. 18, p. 116-137, 10 pl. (1-10). n g u yên, d.t. (1986b): appendix 3 foraminifera and algae from the permian of guguk bulat and silungkang, sumatra.c.c.o.p. technical bulletin, bangkok, vol. 18, p. 138-147, 5 pl. (11-15). n g u yên, d.t. (1989): vi (a). middle permian foraminifera.in: fontaine, h. & gafoer, s. (eds.): the pre-tertiary fossils of sumatra and their environments. ccop technical bulletin, bangkok, vol. 19, p. 113-148, 16 pl. (20-35). n g u yên, l.t. (1970): some permian fossil algae from viet-nam, cambodia and laos.archives géologiques du viêt-nam, saïgon, n° 13, fasc. 2, p. 1-42, 9 pl. h.-t. (i-ix). nicol, s.a. (1987): a down-slope upper triassic reef mound: aflenz limestone, hochschwab mountains, northern calcareous alps.facies, erlangen, 16, p. 23-35, 2 pl. (4-5). n o é, s.u. (1987): facies and paleogeography of the marine upper permian and the permian-triassic boundary in the southern alps (bellerophon formation, tesero horizon).facies, erlangen, 16, p. 89142, 11 pl. (22-32). nowiński, a. (1990): some carboniferous permian organisms from the coral-bearing strata of spitsbergen.polish polar research, warszawa, vol. 11, 34, p. 317-329, 4 pl. h.-t. (1-4). ogilvie-gordon, m.m. (1927): das grödener-, fassaund enneberggebiet in den südtiroler dolomiten. geologische beschreibung mit besonderer berücksichtigung der überschiebungserscheinungen.-abhandlungen der geologischen bundesanstalt, wien, band xxiv, heft 2, 89 p., 13 pl. h.-t. (1-13, i-xiii) ogilvie-gordon, m.m. (1935): geologie von cortina d’ampezzo und cadore.jahrbuch der geologischen bundesanstalt, wien, band lxxxiv (1934), p. 59-215, 17 pl. h.-t. (iii-xix). ogorelec, b. & rothe, p. (1993): m i k r o f a z i e s , diagenese und geochemie des dachsteinkalkes und hauptdolomits in süd-west-slowenien [mikrofacies, diageneza in geohemija dachsteinskega apnenca ter glavnega dolomita v jugozahodni sloveniji].geologija, ljubljana, knjiga 35 (1992), p. 81-181, 4 pl. (1-4). ogorelec, b., jurkov©ek, b., ©ribar, l., jelen, b., stojanovi∆, b. & mi©i∆, m. (1984): karnijske plasti v tamarju in pri logu pod mangartom.geologija razprave in poroëila, ljubljana, knjiga 27, p. 107-158, 11 pl. (1-11). okla, s.m. (1992): permian algae and algal micofacies from unayzah, quassim district, saudi arabia.facies, erlangen, 27, p. 217-224, 2 pl. (45-46). okla, s.m. (1994): fossil algae from saudi arabia revisited.rivista italiana di paleontologia e stratigrafia, milano, vol. 99, n° 4, p. 441-460, 2 pl. h.-t. (1-2). oravecz-scheffer, a. (1987): a dunántúli-középhegység triász képzödményeinek foraminiferái [triassic foraminifers of the transdanubian central r a n g e].geologica hungarica, series paleontologica, budapest, 50, 331 p., 98 pl. h.-t. (i-xcviii). ott, e. (1963): untersuchungen an ladinischen dasycladaceen aus den nördlichen kalkalpen.inaugural-dissertation, doktor der naturwissenschaften, mathematisch-naturwissenschaftlichen fakultät der eberhard-karls-universität, tübingen. ernst ott, schlußberg ü. rosenheim, 43 p. ott, e. (1966): die gesteinsbildenden kalkalgen im schlauchkar (karwendelgebirge).jahrbuch des vereins zum schutze der alpenpflanzen und -tiere e. v., münchen, band 31, p. 152-159. ott, e. (1967): dasycladaceen (kalkalgen) aus der nordalpinen obertrias.mitteilungen der bayerische staatssammlung für paläontologie und historische geologie, münchen, heft 7, p. 205-226, 2 pl. h.-t. (12-13). 184 geologia croatica 53/1 ott, e. (1968): zur nomenklatur obertriadischer kalkalgen, besonders der gattungen h e t e r o p o r e l l a p r a t u r l o n und p o i k i l o p o r e l l a p i a ( d a s y c l a d aceae).mitteilungen der bayerische staatssammlung für paläontologie und historische geologie, münchen, heft 8, p. 253-262. o t t, e. (1972a): die kalkalgen-chronologie der alpinen mitteltrias in angleichung an die ammonitenchronologie.neues jahrbuch für geologie und paläontologie, abhandlungen, stuttgart, band 141, heft 1, p. 81-115. o t t, e. (1972b): mitteltriadische riffe der nördlichen kalkalpen und altersgleiche bildungen auf karaburun und chios (ägäis).in: mikrofazies und mikrofauna der alpinen trias und deren nachbargebiete (symposium innsbruck, 20.-23. märz 1972). mitteilungen der gesellschaft der geologieund bergbaustudenten in österreich, innsbruck, band 21, teil 1, p. 251-276, 2 pl. (i-ii). ott, e. (1972c): neufunde anisischer dasycladaceen (kalkalgen) in österreich.anzeiger der mathematisch-naturwissenschaftlichen klasse der österreichischen akademie der wissenschaften, wien, jahrgang 1972, n° 9, p. 187-200. ott, e. (1974): algae (dasycladaceae).in: zapfe, h. (ed.): catalogus fossilium austriae. eine systematisches verzeichnis aller auf österreichischen gebiet festgestellten fossilien, heft xviib. österreichischen akademie der wissenschaften, wien (springer-verlag, wien), 64 p. ott, e. (1975): teutloporella echinata n. sp., eine neue dasycladacee aus dem esinokalk der lombardischen alpen (mitteltrias, norditalien).mitteilungen der bayerische staatssammlung für paläontologie und historische geologie, münchen, heft 15, p. 113-117, 1 pl. h.-t. (10). ozawa, y. (1925): paleontological and stratigraphical studies in the permo-carboniferous limestone of nagato. part ii. paleontology.journal of the college of science, tokyo imperial university, vol. xlv, article 6, p. 1-90, 14 pl. h.-t. (i-xiv). p a n t i ∆, s. (1959): macroporella alpina p i a sa planine bjelasice (crna gora) [macroporella alpina p i a aus den bjelasica-gebirge (montenegro)]. geoloπki glasnik [bulletin géologique], titograd (podgorica), knjiga [l i v r e] iii, p. 49-52, 1 pl. h.-t. (vi). p a n t i ∆, s. (1961): nova nalaziπta teutloporella her c u l e a s t o p p a n i [new deposits of alga t e u t l o porella herculea s t o p p a n i].vesnik, serija a (geologija) [bulletin, série a (géologie)], beograd, knjiga [tome] xix, p. 189-194, 3 pl. h.-t. (i-iii). panti∆, s. (1963): gornjopermski mikrofosili iz anizijskih konglomerata haj nehaja crna gora [l e s microfossiles permiens supérieures des conglomérats anisiens de haj-nehaj monténégro].vesnik, serija a (geologija) [bulletin, série a (géologie)], beograd, knjiga [tome] xxi, p. 145-167, 10 pl. h.t. (i-x). panti∆, s. (1965): clypeina beπiêi sp. nov. iz trijaskih sedimenata spoljaπnjih dinarida [clypeina beπiêi sp. nov. des sédiments triassiques des dinarides e x t e r n e s].geoloπki glasnik [bulletin géologique], titograd (podgorica), knjiga [l i v r e] iv, p. 133141, 6 pl. h.-t. (i-vi). p a n t i ∆, s. (1967): mikropaleontoloπke karakteristike srednjeg i gornjeg trijasa planine tare (zapadna srbija) [les caractéristiques micropaléontologiques du trias moyen et supérieur de la montagne tara (serbie occidentale)].vesnik, serija a (geologija) [bulletin, série a (géologie)], beograd, knjiga [t o m e] xxiv/xxv ( 1 9 6 6 1 9 6 7 ), p. 245-254, 8 pl. h.-t. (i-viii). p a n t i ∆, s. (1969): litostratigrafske i mikropaleontoloπke karakteristike srednjeg i gornjeg perma zapadne srbije [caractéristiques lithostratigraphiques et micropaléontologiques du permien moyen et supérieur de la serbie occidentale lithostratigraphy and micropaleontology of the middle and upper permian of western serbia].vesnik, serija a (geologija) [bulletin, série a (géologie)], beograd, knjiga [t o m e] xxvii (1969), p. 201216 & 239-272, 10 pl. (i-x). p a n t i ∆, s. (1970): mikropaleontoloπke karakteristike trijaskog stuba antiklinale ædrela (istoëna srbija) [caractéristiques micropaléontologiques de la colonne triasique de l’anticlinal de ædrelo (serbie orient a l )].vesnik, serija a (geologija) [bulletin, série a (géologie)], beograd, knjiga [t o m e] xxviii, p. 377-386, 13 pl. h.-t. (i-xiii). p a n t i ∆, s. (1972a): mikropaleontoloπke i biostratigrafske odlike trijaskih karbonatnih sedimenata u buπotini sb-2 na profilu brane he mratinje (crna gora).vesnik, serija a (geologija) [bulletin, série a (géologie)], beograd, knjiga [t o m e] x x i x / xxx (1971-1972), p. 271-308, 15 pl. h.-t. (i-xv). panti∆, s. (1972b): prvi nalazak trijaskih mikrofosila u oblasti muënja, ovëara, kablara i jelice (zapadna srbija) [first discovery of triasic microfossiles in the region of muëanj, ovëar, kablar and jelica (western serbia)].glasnik prirodnjaëkog muzeja, beograd, serija a, knjiga 27 [bulletin du muséum d’histoire naturelle de belgrade, beograd, série a, livre 27], p. 223-241, 5 pl. h.-t. (i-v). panti∆, s. (1974): prilozi za stratigrafiju trijasa prokletija [contributions to the stratigraphy of the triassic of the prokletije mountains].vesnik, serija a (geologija) [bulletin, série a (géologie)], beograd, knjiga [t o m e] xxxi/xxxii (19731974), p. 135-167, 9 pl. (i-ix). 185granier & grgasoviê: les algues dasycladales du permien et du trias... panti∆, s. & rampnoux, j.p. (1972): concerning the triassic in the yugoslavian inner dinarids (southern serbia, eastern montenegro): microfacies, microfaunas, an attempt to give a paleogeographic reconstitution.in: mikrofazies und mikrofauna der alpinen trias und deren nachbargebiete (symposium innsbruck, 20.-23. märz 1972). mitteilungen der gesellschaft der geologieund bergbaustudenten in österreich, innsbruck, band 21, teil 1, p. 311-326, 3 pl. h.-t. (i-iii). panti∆-prodanovi∆, s. (1975): trijaske mikrofacije dinarida. crna gora, istoëna bosna i hercegovina i zapadna srbija [les microfaciès triasiques des dinarides. le monténégro, la bosnie orientale et l’hérzegovine et serbie oceidentale].druπtvo za nauku i umjetnost crne gore, titograd (podgorica), posebna izdanja, kniga iv, odjeljenje prirodnih nauka, knjiga 4 [société des sciences et des arts du monténégro, monographies, titograd (podgorica), vol. iv, classe de sciences naturelles, vol. 4], 56 p., 100 pl. h.-t. (i-c). panti∆-prodanovi∆, s. (1994): mikropaleontoloπke i biostratigrafske karakteristike gornjepermskih i donjetrijaskih sedimenata u severozapadnoj srbiji (jugoslavija) i oblast planine cera: lokalnost petkovica i neëaje [micropaleontologic and biostratigraphic characters of upper permian and lower triassic sediments in northwestern serbia i cer mountain: petkovica nad neëaje localities]. geoloπki anali balkanskoga poluostrva [a n n a l e s géologiques de la péninsule balkanique], beograd, knjiga lviii, sveska 2, p. 129-168, 2 fig., 8 pl. h.-t. (i-viii). panti∆-prodanovi∆, s. (1995): mikrofosili donjeg i srednjeg trijasa u jugozapadnom delu bosanskog podrinja [lower and middle triassic microfossils in southwestern areas of bosnian podrinje]. geoloπki anali balkanskoga poluostrva [a n n a l e s géologiques de la péninsule balkanique], beograd, knjiga lix, sveska 2, p. 155-178, 2 fig., 6 pl. h.-t. (i-vi). panti∆-prodanovi∆, s. (1996): mikropaleontoloπke i biostratigrafske karakteristike gornjepermskih i donjetrijaskih sedimenata u severozapadnoj srbiji (jugoslavija) iii, oblast planine vlaπiê: lokalnost paniêa peêina i gaj [micropaleontologic and biostratigraphic characters of upper permian and lower triassic deposits of northwestern serbia, yugoslavia iii, mt. vlaπiê region: localities paniêa cave and gaj].geoloπki anali balkanskoga poluostrva [annales géologiques de la péninsule balkan i q u e], beograd, knjiga lx, sveska 1, p. 195-218, 2 fig., 2 pl. h.-t. (i-ii). panti∆-prodanovi∆, s. (1997): gornjopermski sedimenti na geoloπkim stubovima kod dvorske i krasave sa osvrtom na horizont sa biohermama od richthofenia (okolina krupnja, severozapadna srbija) [upper permian rocks in geologic sections of dvorska and krasava, with particular reference to the horizon with richthofenia bioherms (krupanj environs, northwestern serbia].geoloπki anali balkanskoga poluostrva [annales géologiques de la péninsule balkanique], beograd, knjiga lxi, sveska 1, p. 167-201, 2 fig., 5 pl. h.-t. (i-v). papastamatiou, j. & reichel, m. (1956): s u r l’âge des phyllades de l’île de crête.eclogae geologicae helvetiae, basel, vol. 49, n° 1, p. 147-149. papp, a. & turnovsky, k. (1970): anleitung zur biostratigraphischen auswertung von gesteinsschliffen (microfacies austriaca).jahrbuch der geologischen bundesanstalt, wien, sonderband 16, p. 150, 88 pl. h.-t. (1-88). parente, m. & climaco, a. (1999): d a s y c l a d acean green algae from the upper triassic of mt. rotonda (verbicaro unit, calabria-lucania border, southern italy).facies, erlangen, 41, p. 159-182, 7 pl. (34-40). p a s t w a l e s z c z yńska, c. & śl i w iński, s. (1960): wystepowanie glonów (dasycladaceae) w dolomitach kruszconośnych okolic chrzanowa [a lgae (dasycladaceae) from orebearing dolomites in the vicinity of chrzanów].kwartalnik geologiczny, warszawa, tom 4, n° 3, p. 679-699, 4 pl. h.-t. (i-iv). patrulius, d. (1970): inventar sumar al algelor dasycladaceae triasice din carpatii românesti.dǎri de seamǎ ale ş e d i nţelor, bucureşti, vol. lv (19671968), 3. paléontologie, p. 187-196, 5 pl. h.-t. (i-v). pelhâte-peron, a. (1967, i n é d i t): m i c r o p a l é o ntologie des calcaires dinantiens du bassin de laval.thèse de docteur-ès-sciences naturelles, deuxième thèse, faculté des sciences de rennes, 64 p., 8 pl. h.-t. (i-viii). pelhâte-peron, a. (1969): micropaléontologie des calcaires dinantiens du bassin de laval.bulletin de la société géologique et minéralogique de bretagne, rennes, 1967, p. 27-76, 6 pl. (i-vi). perret, m.-f. (1971): les calcaires carbonifères d’ ardengost (hautes-pyrénées).thèse 3e c y c l e , géologie, université paul sabatier. travaux du laboratoire de géologie-pétrologie de l’université paul sabatier, toulouse, 158 p. (chapitre: algues, p. 124-127, pl. xi & xxx-xxxi). peræel, m. (1966): stratigraphie der trias der choëdecke des biele pohorie der malé karpaty.g e o l o g i c ký sborník geologica carpathica, bratislava, roëník xvii, »íslo 1, p. 157-166, 2 pl. h.-t. (xviii-xix). petek, t. (1998): skitske in anizijske plasti v kamnolomu pri hrastenicah in pomembne najdbe zgor186 geologia croatica 53/1 njeanizijskih fosilov [scythian and anisian beds in the quarry near hrastenice and important finds of upper anisian fossils].geologija, ljubljana, knjiga 40, p. 119-151, 5 pl. (1-5). pfeiffer, j. (1988): paleontology and microfacies of a platform margin in the carnic alps (austria, middle triassic).facies, erlangen, 19, p. 33-60, 8 pl. (7-14). pia, j. v o n (1912): neue studien über die triadischen siphoneae verticillatae .beiträge zur paläontologie und geologie österreich-ungarns und des orients, wien & leipzig, band xxv, p. 25-81, 7 pl. h.-t. (ii-viii [i-vii]). pia, j. v o n ( 1 9 1 5a): diplopora debilis g ü m b.in: spitz, a. & dyhrenfurth, g.: monographie der engadiner dolomiten zwischen schuls, sc a n f s und dem stilfserjoch. beiträge zur geologischen karte der schweiz, bern, n.f., vol. 44, p. 46-47, 1 pl. (i). pia, j. v o n ( 1 9 1 5b ): griphoporella curvata g ü m b. sp.in: spitz, a. & dyhrenfurth, g.: monographie der engadiner dolomiten zwischen sc h u l s , scanfs und dem stilfserjoch. beiträge zur geologischen karte der schweiz, bern, n.f., vol. 44, p. 62, 1 pl. (i). pia, j. von (1917): familie: dasycladaceae (endl.) cram. em.in: trauth, f. (ed.): das eozänvorkommen bei radstat im pongau und seine beziehungen zu den gleichalterigen ablagerungen bei kirchberg am wechsel und wimpassing am leithagebirge. denkschriften der mathem.-naturw. klasse, wien, vol. 95, p. 171-278. pia, j. von (1920): die s i p h o n e a e v e r t i c i l l a t a e v o m karbon bis zur kreide.abhandlungen der zoologisch-botanischen gesellschaft in wien, band xi, heft 2, 263 p., 8 pl. (i-viii) [les siphonées verticillées du carbonifère au crétacé (1961).editions technip, rueil-malmaison, 236 p., 8 pl. h.-t. (1-8)]. pia, j. v o n (1922): einige ergebnisse neuerer untersuchungen über die geschichte der siphoneae verti c i l l a t a e .zeitschrift für induktive abstammungsund vererbungslehre, leipzig, band xxx, p. 6398, 1 pl. h.-t. pia, j. v o n ( 1 9 2 4a): einige dasycladaceen aus der ober-trias der molukken.in: brouwer, h.a. (ed.): geologische onderzoekinen in den oostellijken oost-indischen archipel. jaarboek van het mijnwezen in nederlandsch oost-indiè, verhandelingen, jaargang 52 (1923), p. 137-150, 1 pl. h.-t. (i). pia, j. v o n ( 1 9 2 4b): einige neue oder ungenügend bekannte s i p h o n e a e v e r t i c i l l a t a e aus dem mitteleuropäischen malm.annalen des naturhistorischen museums in wien, bande xxxviii, p. 82-88, 1 pl. h.-t. (i). pia, j. v o n (1925): die diploporen der trias von süddalmatien.sitzungsberichte der akademie der wissenschaften in wien, mathematisch-naturwissenschaftliche klasse, abteilung i, band 133 (1924), heft 7-8, p. 329-346, 1 pl. h.-t. (i). pia, j. v o n (1927): 1. abteilung: thallophyta.in: hirmer, m. (ed.): handbuch der paläobotanik. oldenbourg, münchen & berlin, band i, p. 31-136. pia, j. v o n (1928): die anpassungsformen der kalkalgen.palaeobiologica, wien & leipzig, band i, p. 211-224, 8 pl. h.-t. (xv-xxii). pia, j. von (1930): upper triassic fossils from the burmo-siamese frontier. a new dasycladacea, h o l o sporella siamensis nov. gen., nov. sp., with a description of the allied genus aciculella pia.records of the geological survey of india, calcutta, vol. lxiii, part 1, p. 177-181, 1 pl. h.-t. (4). pia, j. v o n (1931): die dasycladaceen der germanischen trias.annalen des naturhistorischen museums in wien, band xlv, p. 265-279, 1 pl. h.-t. (xxi). pia, j. v o n (1932): saal vi. fossile pflanzen. geologisch-paläontologische sammlungen.sonderabdruck aus dem allgemeinen führer durch das naturhistorische museum in wien, teil i, p. 2-16. pia, j. v o n ( 1 9 3 5a): die diploporen der anisischen stufe bosniens.geoloπki anali balkanskog poluostrva [annales géologiques de la péninsule balkan i q u e], beograd, knjiga xii, deo 2, p. 190-246, 5 pl. h.-t. (i-v). pia, j. v o n ( 1 9 3 5b): algen und pseudoalgen aus der spanischen trias.in: schmidt, m. (ed.): fossilien der spanischen trias. abhandlung heidelberger akad. d. wiss., m.-n. kl., heidelberg, abh. 22, p. 9-17, 2 pl. h.-t. (i-ii). pia, j. von (1936): description of the algae.in: rao, l.r., & pia, j. v o n : fossil algae from the uppermost cretaceous beds (the niniyur group) of the trichinopoly district, s. india. memoirs of the geological survey of india, palaeontologia indica, calcutta, new series, vol. xxi, n° 4, p. 13-44, 5 pl. h.t. (i-v). pia, j. v o n (1937): die wichtigsten kalkalgen des jungpaläozoikums und ihre geologische bedeutung.deuxième congrès pour l’avancement des études de stratigraphie carbonifère (1935), compte-rendu, heerlen, t. ii, p. 765-856, 13 pl. h.-t. (85-97). pia, j. v o n ( 1 9 4 0a): vorläufige übersicht der kalkalgen des perms von nordamerika.sitzungsberichte der akademie der wissenschaften in wien, mathematisch-naturwissenschaftlichen klasse, akademischen anzeiger, jahrgang 77, n° 1-15, p. 5560. 187granier & grgasoviê: les algues dasycladales du permien et du trias... pia, j. v o n ( 1 9 4 0b): wirtelalgen (dasycladaceen) aus den anisischen kalken des szilicei fennsík in nordungarn [a szilicei fennsík anisusi mészköveinek d a s y c l a d a c e a a l g á i].abhandlungen aus dem mineralogisch-geologischen institut der st. tisza-universität in debrecen [közlemények a debreceni tisza istván-tudományegyetem ásvány és földtani intézetéböl], band iv, n° 18, p. 1-7, 1 pl. h.-t. pia, j. v o n ( 1 9 4 0c): die gesteinbildenden algen des höllengebirges.jahrbuch des vereines für landeskunde und heimatpflege im gau oberdonau, linz, band 89, p. 241-266, 6 pl. h.-t. (1-6). pia, j. v o n ( 1 9 4 1a): kalkalgen der adria und ihre fossilen verwandten.senckenbergische naturforschende gesellshaft, “natur und volk”, frankfurt am main, 71, p. 39-49. pia, j. von (1941b): einige geologische ergebnisse der untersuchung fossiler kalkalgen.senckenbergische naturforschende gesellshaft, “natur und volk”, frankfurt am main, 71, p. 84-90. pia, j. v o n (1942): uebersicht über fossile kalkalgen und die geologischen ergebnisse ihrer untersuchung (vortrag).mitteilungen des alpenländischen geologischen vereines (mitteilungen der geologischen gesellschaft in wien), band 33 (1940), p. 1134. pia, j. v o n (1943): geologisches untersuchungen in der salmgruppe (oberdonau).annalen des naturhistorischen museums in wien, band 53, teil i (1942), p. 5-155, 7 pl. h.-t. (i-vii). piller, w.e. (1981): the steinplatte reef complex, part of an upper triassic carbonate platform near salzburg, austria.in: t o o m e y, d.f. (ed.): european fossil reef models. sepm special publication, tulsa, n° 30, p. 261-290. poncet, j. (1987): e o c l y p e i n a, un nouveau genre d’algue verte calcaire (dasycladaceae) dans le carbonifère supérieur du bassin de béchar (sahara algérien) avec eoclypeina crassa n. sp.revue de micropaléontologie, paris, vol. 30, n˚ 2, p. 117-121, 1 pl. h.-t. (1). popa, e. & dragastan, o. (1973): alge şi foraminifere triasice (anisian ladinian) din estul pǎd u r i i craiului (munţii apuseni).studii şi cercetǎri de geologie, geofizicǎ, geografie, seria geologie, bucureşti, tomul 18, n° 2, p. 425-442, 22 pl. h.-t. (ixxii). praturlon, a. (1963): dasycladaceae from upper permian of the dolomites (italy).geologica romana, roma, vol. ii, p. 119-137, 5 pl. h.-t. (i-v). praturlon, a. (1967): heteroporella lepina , new dasyclad species from upper cenomanian lower turonian of central apennines.bollettino della società paleontologica italiana, modena, vol. 5 (1966), n° 2, p. 202-205, 2 pl. h.-t. (51-52). pugliese, a. (1995): some observations on macrop orella retica zanin buri 1965 dasycladacean green alga from the upper triassic.rivista italiana di paleontologia e stratigrafia, milano, vol. 100, n° 4, p. 537-546, 3 pl. h.-t. (1-3). pugliese, a. (1997): middle-late triassic dasycladales (green algae) from brenta dolomites (giudicarie alps, italy).rivista italiana di paleontologia e stratigrafia, milano, vol. 103, n° 1, p. 71-80, 2 pl. (1-2). raciborski, m. (1892): zapiski paleobotaniczne.odbitka z kosmosu, lwów, zeszyt xi-xii, 8 p. rácz, l. (1966, pre-issued 14-10-1964): carboniferous calcareous algae and their associations in the san emiliano and lois-ciguera formations (prov. leon, nw spain).leidse geologische mededelingen, leiden, deel 31 (1966), p. 1-112, 13 pl. h.-t. (ixiii). rácz, l. (1966): late palaeozoic calcareous algae in the pisuerga basin (n-palencia, spain).leidse geologische mededelingen, leiden, deel 31 (1965), p. 241-260, 8 pl. h.-t. (i-viii). r a d o i » i ∆, r. (1962): o jednoj novoj gornjojurskoj dazikladacei pianella grudii nov. gen., nov. spec. [sur une dasycladacée nouvelle du jurassique supérieur pianella grudii nov. gen., nov. sp.].vesnik, serija a (geologija) [bulletin, série a (géologie)], beograd, knjiga [t o m e] xx, p. 190-199 & 201210, 3 pl. h.-t. (i-iii). radoi»i∆, r. (1969): likanella ? danilovae n. sp. and some other lower cretaceous dasycladaceae from the outer dinarides.vesnik, serija a (geologija) [bulletin, série a (géologie)], beograd, knjiga [tome] xxvi (1968), p. 237-275, 16 pl. (i-xvi). r a m o v ©, a. (1971): biostratigraphische charakteristik der oberkarbon-schichten in den südkarawanken, nw jugoslawien.sixième congrès international de stratigraphie et de géologie du carbonifère (1967), compte rendu, sheffield, vol. iv, p. 13871390, 3 pl. h.-t. (1-3). ramov©, a. (1972): mikrofauna der alpinen und voralpinen trias sloweniens.in: mikrofazies und mikrofauna der alpinen trias und deren nachbargebiete (symposium innsbruck, 20.-23. märz 1972). mitteilungen der gesellschaft der geologieund bergbaustudenten in österreich, innsbruck, band 21, teil 1, innsbruck, p. 413-426, 3 pl. (i-iii). r a m o v ©, a. (1978): okamnelo æivljenje v jeseniπkem prostoru.vodnik po paleontoloπki zbirki tehniπkega muzeja æelezarne jesenice, jesenice, 80 p. ramov©, a. (1980): po poteh okamnelega æivljenja v træiπkem prostoru.druπtvo prijateljev mineralov in fosilov, træië, 80 p. r a m o v ©, a. & k o c h a n s k y d e v i d é , v. (1979): karbonske in permske plasti v severnih julijskih 188 geologia croatica 53/1 alpah [karbonund perm-schichten in den nördlichen julischen alpen].geologija razprave in poroëila, ljubljana, knjiga 22, del 1, p. 21-54, 6 pl. (1-6). r a m o v ©, a. & k o c h a n s k y d e v i d é , v. (1981): karbonske in permske plasti pri logu v julijskih alpah [carboniferous and permian beds at log in the julian alps].geologija razprave in poroëila, ljubljana, knjiga 24, del 1, p. 91-107, 3 pl. (1-3). rauzer-chernousova, d.m. & dalmatskaja, i.i. (1954): stratigrafija i foraminifery srednekamennougol’nykh otlozhenij jugo-vostochnoj okrainy moskovskoj sineklizy (tokmovskij svod).in: rauzer-chernousova, d.m., rejtlinger, e.a., balashova, n.n., dalmatskaja, i.i. & chernova, e.i. (eds.): stratigrafija srednekamennougol’nykh otlozhenij central’noj i vostochnoj chastej russkoj platformy (na osnove izuchenija foraminifer). regional’naja stratigrafija sssr, akademija nauk sssr, moskva, tom 2, p. 201-254, 10 pl. h.-t. (i-x). rauser-chernousova, d.m. & koroljuk, j.k. (1981): k morfologii i sistematike pozdnemoskovskikh sifonovykh vodoroslej juzhnogo urala i ob ikh roli v porodoobrazovanii [on the morphology and systematic of late moscovian siphonal algae in the south urals and their significance in rock formation].voprosy mikropaleontologii, 24, sistematika i morfologija mikroorganizmov [questions of micropaleontology, 24, sistematics and morphology of microfossils], akademija nauk sssr, moskva, p. 157-170, 4 pl. h.-t. (i-iv). reis, o.m. (1926): die fauna des wettersteinkalkes. iii teil gasteropoden, bivalven, brachiopoden.geognostische jahreshefte, münchen, jahrgang xxxix, p. 87-138, 10 pl. h.-t. (i-x). rezak, r. (1959): permian algae from saudi arabia.journal of paleontology, tulsa, vol. 33, n° 4, p. 531-539, 2 pl. h.-t. (71-72). rich, m. (1967): d o n e z e l l a and d v i n e l l a, widespread algae in lower and middle pennsylvanian rocks in east-central nevada and west-central utah.journal of paleontology, tulsa, vol. 41, n° 4, p. 973-980, 2 pl. h.-t. (125-126). riding, r. & guo, l. (1991): chapter 20. permian marine calcareous algae.in: r i d i n g, r. (ed.): calcareous algae and stromatolites. springer-verlag, berlin, p. 452-480. riding, r. & jansa, l.f. (1974): u r a l o p o r e l l a k o r d e in the devonian of alberta.canadian journal of earth sciences, ottawa, vol. 11, n° 10, p. 1414-1426, 2 pl. (1-2). riding, r. & jansa, l.f. (1976): devonian occurrence of u r a l o p o r e l l a (? foraminifer) in the canning basin, western australia.journal of paleontology, tulsa, vol. 50, n° 5, p. 805-807. rinaldo, m. & jadoul, f. (1994): la successione anisico superiore-carnica delle dolomiti di brenta (trentino occidentale).studi trentini di scienze naturali acta geologica, trento, vol. 69 (1992), p. 93-118. röhl, u., dumont, t., rad, u. von, martini, r. & zaninetti, l. (1991): upper triassic tethyan carbonates off northwest australia (wombat plateau, odp leg 122).facies, erlangen, 25, p. 211-252, 7 pl. (56-62). rosenberg, g. & zapfe, h. (1954): l e i t f o s s i l i e n der trias.in: götzinger, h.g., grill, r., küpper h., lichtenberger, e. & rosenberg, g. (eds.): erläuterungen zur geologischen karten der umgebung von wien, 1:75.000. geologische bundesanstalt, ausgabe 1952, wien, 138 p., 15 pl. h.-t. (1-15). rossi, d. (1967): capitolo x. dolomia del serla e calcare di contrin (anisico medio-superiore).in: leonardi, p. (ed.): le dolomiti. geologia dei monti tra isarco e piave. consiglio nazionale delle ricerche e della giunta provinciale di trento, vol. 1, p. 135-142. rothpletz, a. (1894): ein geologischer querschnitt durch die ostalpen nebst anhang über die sog. glarner doppelfalte.e. schweizerbart’sche verlag, stuttgart, 268 p. roux, a. (1979a, inédit): algues du paléozoïque supérieur du bassin de sverdrup, archipel arctique canadien.thèse, doctorat en sciences, université libre de bruxelles, 296 p., 33 pl. h.-t. (1-33). roux, a. (1979b): révision du genre e p i m a s t o p o r a “p i a, 1922” (dasycladaceae).in: 2è m e s y m p o s i u m international sur les algues fossiles (paris, 23-26 avril 1979). bulletin des centres de recherches exploration-production elf-aquitaine, pau, vol. 3, n° 2, p. 803-810. roux, a. (1985): introduction à l’étude des algues fossiles paléozoïques (de la bactérie à la tectonique des plaques).bulletin des centres de recherches exploration-production elf-aquitaine, pau, vol. 9, n° 2, p. 465-699, 6 pl. (1-6). roux, a. (1989): study of a paraepimastopora kan s a s e n s i s (dasyclad alga) topotypical material from the upper pennsylvanian of kansas, u.s.a.revue de paléobiologie, genève, vol. 8, n° 2, p. 323-333, 3 pl. (i-iii). sadati, s.m. (1981): die hohe wand: ein obertriadisches lagunen-riff am ostende der nördlichen kalkalpen (niederösterreich).facies, erlangen, 5, p. 191-264, 13 pl. (54-66). salaj, j. (1977): contribution à la microbiostratigraphie du trias des carpates occidentales tchécoslovaques.in: actes du vi° colloque africain de 189granier & grgasoviê: les algues dasycladales du permien et du trias... micropaléontologie (tunis 1974). annales des mines et de la géologie, tunis, n° 28, p. 103-127, 7 pl. (i-vii). salomon, w. (1895): geologische und paläontologische studien über die marmolata.paläontographica, stuttgart, band xlii, p. 120-240, 8 pl. h.-t. (iviii). s a l t o v s k a j a, v.d. (1984): o morfologii roda u r a l o p o r e l l a k o r d e , 1950.in: problematiki paleozoja i mezozoja. akademija nauk sssr, sibirskoe otdelenie, institut geologii i geofiziki, moskva, trudy 597, p. 19-22, 2 pl. h.-t. (xii-xiii). samankassou, e. (1997): palaeontological response to sea-level change: distribution of fauna and flora in cyclothems from the lower p s e u d o s c h w a g e r i n a limestone (latest carboniferous, carnic alps, austria).géobios, lyon, n° 30, fasc. 6, p. 785-796. samankassou, e. (1998): skeletal framework mounds of dasycladalean alga anthracoporella , upper paleozoic, carnic alps, austria.palaios, tulsa, vol. 13, p. 297-300. samankassou, e. (1999): drowning of algal mounds: records from the upper carboniferous p s e u d o s c h w a g e r i n a limestone, carnic alps, austria.sedimentary geology, amsterdam, vol. 127, p. 209220. samuel, o., borza, k. & köhler, e. (1972): microfauna and litostratigraphy of the paleogene and adjacent cretaceous of the middle vah valley (west carpathian).geologický ústav dionýza ©tura, bratislava, 246 p., 180 pl. h.-t. (i-clxxx). sartorio, d. & venturini, s. (1988): s o u t h e r n tethys biofacies.agip, milano, 235 p. scandone, p. (1967): studi di geologia lucana: la serie calcareo-silico-marnosa e suoi rapporti con l’appennino calcareo.bollettino della società dei naturalisti in napoli, vol. lxxvi istituto di geologia dell’universita di napoli, pubblicazione n. 209, 175 p., 17 pl. h.-t. (i-xvii). schäfer, p. (1979): fazielle entwicklung und palökologische zonierung zweier obertriadischer riffstrukturen in der nördlichen kalkalpen (“oberrhät”riff-kalke, salzburg).facies, erlangen, 1, p. 3245, 21 pl. (1-21). schäfer, p. & senowbari-daryan, b. (1982): the upper triassic pantokrator limestone of hydra (greece): an example of a prograding reef complex.facies, erlangen, 6, p. 147-164, 3 pl. (19-21). schäfer, p. & senowbari-daryan, b. (1983): die kalkalgen aus der obertrias von hydra, griechenland [the calcareous algae of the upper triassic of hydra, greece].palaeontographica, stuttgart, abteilung b, band 185, lieferung 4-6, p. 83-142, 10 pl. h.-t. (1-10). schafhäutl, k.e. (1853): beiträge zur näheren kenntnis der bayern’schen voralpen.neues jahrbuch für mineralogie, geologie und paläontologie, stuttgart, 1853, p. 299-319, 1 pl. h.-t. (vi). schafhäutl, k.e. (1863): süd-bayerns lethaea geognostica. geognostisch betrachtet in ihren petrefacten.l. voss, leipzig, xvii + 487 p., 86 pl. (ilxxxvi). schafhäutl, k.e. (1867): weitere beiträge zur näheren kenntnis der bayerischen alpen.neues jahrbuch für mineralogie, geologie und paläontologie, 1867, stuttgart, p. 257-272, 2 pl. h.-t. (i-ii). schalekova, a. (1965): mezozoické fytogénne vapence slovenska.acta geologica et geographica universitatis comenianae, geologica, bratislava, n° 9 (1964), p. 187-212, 4 pl. h.-t. (xxxvixxxix). schauroth, k.f. von (1855): übersicht der geognostischen verhältnisse der gegend von recoaro im vicentinischen.sitzungsberichte der kaiserlichen akademie der wissenschaften in wien, mathematisch-naturwissenschaftlichen classe, wien, band xvii, p. 481-562, 3 pl. h.-t. (i-iii). schauroth, k.f. von (1859): kritisches verzeichniss der versteinerungen der trias im vicentinischen.sitzungsberichte der kaiserlichen akademie der wissenschaften in wien, mathematisch-naturwissenschaftlichen classe, wien, band 34, n° 1-6, p. 283-356, 3 pl. h.-t. (i-iii). scheuber, m. (1990): die spitzkalk von recoaro (vicentinische alpen, norditalien): sedimentologie, paläontologie und paläogeographie eines mitteltriassischen sedimentationsraumes.facies, erlangen, 23, p. 57-96, 4 pl. (9-12). schimper, w.p. & schenk, a. (1890): 3. familie. dasycladeae und polyphyseae kütz. siphoneae verticillatae mun.-chal.in: ii. abtheilung: palaeophytologie. in: zittel, k.a. (ed.): handbuch der palaeontologie. r. oldenbourg, münchen & leipzig, p. 30-36. schindlmayr, w.-e. (1968, inédit): g e o l o g i s c h e untersuchungen in der umgebung von mauls und stilfes in südtirol.inaugural-dissertation zur erlangung der doktorwürde der naturwissenschaftlichen fakultät, ludwig-maximilians-universität, münchen, 113 p., 13 pl. (i-xiii). schmidt, m. (1928): die lebewelt unserer trias.hohenlohe’sche buchhandlung ferdinand rau, oehringen, 461 p. schmidt, m. (1938): die lebewelt unserer trias.hohenlohe’sche buchhandlung ferdinand rau, oehringen, nachtrag 1938, 143 p. schneegans, d. (1933): sur la découverte de nouveaux gisements de diplopores (algues calcaires) 190 geologia croatica 53/1 dans le trias de la zone du briançonnais.travaux du laboratoire de géologie de la faculté des sciences de l’université de grenoble, t. xvii, 1° fasc., p. 59-75, 2 pl. h.-t. (i-ii). scholle, p.a. (1978): a color illustrated guide to carbonate rock constituents, textures, cements, and porosities.american association of petroleum geologists, memoir 27, tulsa, xiv + 241 p. s c h r é t e r, z. (1954): a bükk hegység régi tömegének földtani és vízföldtani viszonyai.hidrológiai közlöny, budapest, évf. 34, sz. 7-8, p. 287-294 & sz. 9-10, p. 369-381, 3 pl. h.-t. (i-iii). schubert, r.j. (1907): vorläufige mitteilung über foraminifera und kalkalgen aus dem dalmatinischen karbon.verhandlungen der kaiserlich-königlichen geologischen reichsanstalt, wien, jahrgang 1907, n° 8, p. 211-214. schubert, r.j. (1909): zur geologie der österreichischen velebit.jahrbuch der kaiserlich-königlichen geologischen reichsanstalt, wien, band lviii (1908), heft 2, p. 345-386, 1 pl. h.-t. (xvi). senowbari-daryan, b. (1978): p e n t a p o r e l l a rhaetica n. g. n. sp., eine neue kalkalge (dasycladaceae) aus dem oberrhätischen gruber-riff (hintersee/salzburg) (beiträge zur paläontologie und mikrofazies obertriadischer riffe im alpinmediterranen raum, 2).paläontologische zeitschrift, stuttgart, vol. 52, n˚ 1/2, p. 6-12. senowbari-daryan, b. (1980): fazielle und paläontologische untersuchungen in oberrhätischen riffen (feichtensteinund gruberriff bei hintersee, salzburg, nördliche kalkalpen).facies, erlangen, 3, p. 1-237, 29 pl. (1-29). senowbari-daryan, b. & abate, b. (1986): zur paläontologie, fazies und stratigraphie der karbonate innerhalb der “formazione mufara” (obertrias, sizilien).naturalista sicil., s. iv, vol. x, n° 1-4, p. 59-104, 12 pl. (1-12). senowbari-daryan, b. & flügel, e. (1993): a1. triassic reefs and platform carbonates in the northern calcareous alps.in: h ö f l i n g, r., m o u s s a v i a n , e. & p i l l e r , w.e. (eds.): facial development of algae-bearing carbonate sequences in the eastern alps. field trip guidebook, alpine algae ’93, münchen, 35 p., 12 pl. (1-12). senowbari-daryan, b. & schäfer, p. (1979): distributional patterns of calcareous algae within upper triassic patch reef structures of the northern calcareous alps (salzburg).in: 2è m e s y m p o s i u m international sur les algues fossiles (paris, 23-26 avril 1979). bulletin des centres de recherches exploration-production elf-aquitaine, pau, vol. 3, n° 2, p. 811-820, 1 pl. (1). senowbari-daryan, b., schäfer, p. & abate, b. (1982): obertriadische riffe und rifforganismen in sizilien (beiträge zur paläontologie und mikrofazies obertriadischer riffe im alpin mediterranen raum, 27).facies, erlangen, 6, p. 165-184, 3 pl. (22-24). senowbari-daryan, b., zühlke, r., bechstädt, t. & flügel, e. (1993): anisian (middle triassic) buildups of the northern dolomites (italy): the recovery of reef communities after the permian/triassic crisis.facies, erlangen, 28, p. 181-256, 26 pl. (40-65). seward, a.c. (1898): fossil plants for students of botany and geology.cambridge university press, cambridge, vol. i, 414 p. s i m i ∆, v. (1933): gornji perm u zapadnoj srbiji [d a s oberperm in westserbien].rasprave geoloπkog instituta kraljevine jugoslavije [mémoires du service géologique du royaume de yougoslavie], beograd, vol. i, 130 p., 9 pl. h.-t. (i-ix). s o k a », b. (1968): a new genus of calcareous algae from the middle triassic of velebit [novi rod vapnenaëke alge iz srednjeg trijasa velebita].geoloπki vjesnik, zagreb, svezak 21 (1967), p. 207-212, 4 pl. h.-t. (i-iv). s o k a », b. (1974): diplopora clavaeformis p i a (chlorophyta, dasycladaceae) from the lower ladinian of mt. velebit [o vrsti diplopora clavaeformis p i a (chlorophyta, dasycladaceae) iz donjeg ladinika velebita].geoloπki vjesnik, zagreb, svezak 27, p. 133-141, 5 pl. h.-t. (i-v). soka», b. & grgasovi∆, t. (1995): dissocladella b y s t r i c k y i n. sp., a new calcareous alga (dasycladaceae) from upper triassic dolomites of mt. medvednica (northern croatia).geologia croatica, zagreb, vol. 48/1, p. 1-7, 2 pl. (i-ii). s o k a », b. & g r g a s o v i ∆ , t. (1998): a s t e r o c a l c u lus heraki n. gen., n. sp., a new calcareous alga (gymnocodiaceae) from the upper triassic hauptdolomite of æumberak, north croatia.facies, erlangen, 38, p. 197-206, 3 pl. (48-50). s o k a », b. & nikler, l. (1973): calcareous algae from the lower cretaceous of the environs of nikπiê, crna gora (montenegro) [vapnenaëke alge donjokrednih naslaga iz okoline nikπiêa u crnoj g o r i].palaeontologia jugoslavica, zagreb, svezak 13, 57 p., 16 pl. h.-t. (i-xvi). s o k a » , b., nikler, l. & i v a n o v i ∆, a. (1964): fund von obertriadischen dasycladaceen im gebiet des velebit.bulletin scientifique, conseil des académies des sciences et des arts de la r.s.f. de yougoslavie, section a: sciences naturelles, techniques et médicales, zagreb, tome 9, n° 6, p. 156157. solms-laubach, h.g. zu (1887): ii. thallophyten, bryinen.in: einleitung in die paläophytologie. leipzig, p. 35-52. 191granier & grgasoviê: les algues dasycladales du permien et du trias... sremac, j. (1991): zona neoschwagerina craticulif era u srednjem velebitu [zone n e o s c h w a g e r i n a craticulifera in the middle velebit mt. (croatia, y u g o s l a v i a )].geologija, ljubljana, 34 (1991), p. 7-55, 13 pl. h.-t. (1-13). sremac, j. & aljinovi∆, d. (1997): upper palaeozoic fossils from clastic sedimentary rocks in the gorski kotar region.geologia croatica, zagreb, 50/2, p. 187-199, 3 pl. h.-t. (i-iii). stanton, r.j. & flügel, e. (1989): problems with reef models: the late triassic steinplatte “reef” (northern alps, salzburg/tyrol, austria).facies, erlangen, 20, p. 1-138, 53 pl. (1-53). steinmann, g. (1880): zur kenntnis fossiler kalkalgen (siphoneen).neues jahrbuch für mineralogie, geologie und paläontologie, stuttgart, band ii, p. 130-140, 1 pl. h.-t. (v). steinmann, g. (1903): “tetraporella remeπi”, eine neue dasycladacea aus dem tithon von stramberg.beiträge zur paläontologie und geologie österreich-ungarns und des orients, wien, band xv, heft ii-iii, p. 45-54. steinmann, g. (1907): einführung in die paläontologie.wilhem engelmann verlag, leipzig, 542 p. stevanovi∆, p.m. & an–elkovi∆, m.æ. (1968): istorijska geologija. ii. paleozojske periode.zavod za izdavanje udæbenika socijalistiëke republike srbije, beograd, viii + 292 p., 24 pl. (i-xxiv). stolley, e. (1893): ueber silurische siphoneen.neues jahrbuch für mineralogie, geologie und paläontologie, stuttgart, band ii, p. 135-146, 2 pl. h.-t. (vii-viii). stoppani, a. (1857): studii geologici e paleontologici sulla lombardia.c. turati, milano, 461 p. stoppani, a. (1858): monographie des acéphales des environs d’esino, près du lac de côme et de lenna, en val-brembana appartenant au dépôt des pétrifications d’esino.in: les pétrifications d’esino ou description des fossiles appartenant au dépôt triasique supérieur des environs d’esino en lombardie. palaéontologie lombarde ou description des fossiles de lombardie (1° série). j. bernardoni, milano, p. 73-107, 8 pl. h.-t. (16-23). stoppani, a. (1865): 2e appendice. sur les grandes bivalves cardiformes aux limites supérieures et inférieures de la zone à avicula contorta.i n : s t oppani, a. (1860-1865): géologie et paléontologie des couches à avicula contorta en lombardie comprenant des aperçus sur l’étage infraliasien en lombardie et en europe en général et deux monographies des fossiles appartenant à la zone supérieure et à la zone inférieure des couches à avicula contorta en lombardie. j. bernardoni, milano, p. 213-260, 23 pl. h.-t. (38-60). strutinsky, c., bucur, i.i., nicu, m., popstratila, d. & török, i. (1987): new data on the stratigraphy and tectonic position of the triassic deposits from sasca montana (banat hills, romania).studia univ. babes-bolyai, cluj-napoca, geologia-geographia, vol. xxxii, n° 2, p. 61-69, 2 pl. h.-t. (i-ii). sudar, m. (1986): mikrofosili i biostratigrafija trijasa unutraπnjih dinarida jugoslavije izmedu guëeva i ljubiπnje [triassic microfossils and biostratigraphy of the inner dinarides between guëevo and ljubiπnja mts., yugoslavia].geoloπki anali balkanskoga poluostrva [annales géologiques de la péninsule balkanique], beograd, knjiga l, p. 151-394, 30 pl. h.-t. (i-xxx). termier, h., termier, g., lapparent, a.f. & marin, p. (1974): monographie du permo-carbonifère de wardak (afghanistan central).documents des laboratoires de géologie de la faculté des sciences de lyon, h.s. 2, 167 p., 38 pl. h.-t. (138). termier, h., termier, g. & vachard, d. (1977): monographie paléontologique des affleurements permiens du djebel tebaga (sud tunisien).palaeontographica, stuttgart, abteilung a, band 156, 109 p., 18 pl. h.-t. (1-18). ti©ljar, j., vlahovi∆, i., sremac, j., veli∆, i., veseli, v. & stankovi∆, d. (1991): excursion a velebit mt. permian jurassic.in: vlahovi∆, i. & veli∆, i. (eds.): the second international symposium on the adriatic carbonate platform (zadar, 1991), excursion guide-book. institute of geology, zagreb, p. 3-49, 7 pl. (i-vii). tollmann, a. (1976): analyse des klassischen nordalpinen mesozoikums. stratigraphie, fauna und fazies der nördlichen kalkalpen.franz deuticke, wien, 580 p. tommasi, a. (1899): la fauna dei calcari rossi e grigi del monte clapsavon nella carnia occidentale.palaeontographia italica, memorie di paleontologia, pisa, vol. v, p. 1-54, 7 pl. h.-t. (i-vii). tommasi, a. (1903): revisione della fauna a molluschi della dolomia principale di lombardia.palaeontographia italica, memorie di paleontologia, pisa, vol. ix, p. 95-124, 3 pl. h.-t. (xvi-xviii). tommasi, a. (1911): i fossili della lumachella triasica del ghegna in valsecca presso roncobello. parte i. algae, anthozoa, brachiopoda, lamellibranchiata.paleontographia italica, pisa, vol. xvii, p. 1-36, 3 pl. h.-t. (i-iii). toomey, d.f. (1969): the biota of the pennsylvanian (virgilian) leavenworth limestone, midcontinent region. part 2: distribution of algae.journal of paleontology, tulsa, vol. 43, n° 6, p. 1313-1330, 4 pl. h.-t. (151-154). 192 geologia croatica 53/1 toomey, d.f., wilson, j.l. & rezak, r. (1977): evolution of yucca mound complex, late pennsylvanian phylloid-algal buildup, sacramento mountains, new mexico.american association of petroleum geologists, bulletin, tulsa, vol. 61, n° 12, p. 2115-2133. tornquist, h.a. (1899): 1. neue beiträge zur geologie und paläontologie der umgebung von recoaro und schio (im vicentin) iii. beitrag: der spitzkalk.zeitschrift der deutschen geologischen gesellschaft, berlin, band 51, heft 3, p. 341-377, 3 pl. h.-t. (xviii-xx). tornquist, h.a. (1900): 5. neue beiträge zur geologie und paläontologie der umgebung von recoaro und schio (im vicentin). iv. beitrag: der sturiakalk (t r i n o d o s u s-niveau).zeitschrift der deutschen geologischen gesellschaft, berlin, band 52, p. 118-153. 3 pl. h.-t. (ii-iv). toschek, p.h. (1968): sedimentological investigations of the ladinian “wettersteinkalk” of the “kaiser-gebirge” (austria).in: müller, g. & friedman, g.m. (eds.): recent developments in carbonate sedimentology in central europa. springer-verlag, berlin, p. 219-227. trifonova, a. (1978): foraminifera zones and subsones of the triassic in bulgaria. ii ladinian and carnian.geologia balcanica, sofia, vol. 8, n° 4, p. 49-64, 5 pl. h.-t. (i-v). turek, v., marek, j. & benes, j. (1988): la grande encyclopédie des fossiles.gründ, paris, 520 p. uro©evi∆, d. (1971): a survey of triassic fauna and flora of stara planina mt. (carpatho-balkan region).geoloπki anali balkanskoga poluostrva [annales géologiques de la péninsule balkanique], beograd, knjiga xxxvi, p. 95-104, 13 pl. h.-t. (ixiii). vachard, d. (1974): sur les dasycladacées métaspondyles “vestibulaires”, à propos d’un de leurs représentants viséens: eovelebitella occitanica n. gen. n. sp.compte rendu de l’académie des sciences, paris, série d, t. 279, p. 1855-1858. vachard, d. (1980): téthys et gondwana au paléozoïque supérieur: les données afghanes; biostratigraphie, micropaléontologie, paléogéographie.thèse doct. etat, documents et travaux igal, paris, n° 2, 2 vol.: 463 p. (texte), 35 pl. (atlas: 1-35). vachard, d. (1985): remarques sur les dasycladales (algues vertes) du permien supérieur du jebel tebaga.actes du premier congrès national des sciences de la terre (tunis, septembre 1981), t. 1, p. 271-281, 3 pl. (1-3). vachard, d. (1988): appendix 4. some foraminifera and algae of the upper triassic of west thailand.in: fontaine, h. & suteethorn, v. (eds.): late paleozoic and mesozoic fossils of west thailand and their environments. ccop technical bulletin, tokyo, vol. 20, p. 135-141, 2 pl. (19-20). vachard, d. (1989): v (b). a rich algal microflora from the lower permian of jambi province.in: fontaine, h. & gafoer, s. (eds.): the pretertiary fossils of sumatra and their environments. ccop technical bulletin, bangkok, vol. 19, p. 5969, 4 pl. (6-9). vachard, d., clift, p. & decrouez, d. (1993): une association à p s e u d o d u n b a r u l a ( f u s u l i n o ï d e ) du permien supérieur (djoulfien) remaniée dans le jurassique d’argolide (péloponnèse, grèce).revue de paléobiologie, genève, vol. 12, n° 1, p. 217-242, 7 pl. (i-vii). vachard, d. & fontaine, h. (1988): b i o s t r a t igraphic importance of triassic foraminifera and algae from south-east asia.revue de paléobiologie, genève, vol. 7, n° 1, p. 87-98, 3 pl. (i-iii). vachard, d., fontaine, h. & caridroit, m. (1992): foraminifera, algae and pseudo-algae from carboniferous and permian limestones of northwest thailand.revue de paléobiologie, genève, vol. 11, n° 1, p. 137-147, 3 pl. (i-iii). vachard, d. & fourcade, e. (1997): f o r a m i n ifères et algues du permien du guatemala.géobios, lyon, n° 30, fasc. 6, p. 745-784. vachard, d., martini, r. & zaninetti, l. (1995): le murgabien à fusulinoïdes des îles d’hydra, crète et mytilène (permien supérieur de grèce).géobios, lyon, n° 28, fasc. 4, p. 395-406, 3 pl. (53-55). vachard, d. & montenat, c. (1981): b i o s t r a t igraphie, micropaléontologie et paléogéographie du permien de la région de tezak (montagnes centrales d’afghanistan).palaeontographica, stuttgart, abteilung b, band 178, lieferung 1-3, p. 1-88, 15 pl. h.-t. (1-15). vachard, d. & razgallah, s. (1988): i m p o rtance phylogénétique d’un nouveau foraminifère endothyroïde: endoteba controversa n. gen. n. sp. (permien du jebel tebaga, tunisie).géobios, lyon, n° 21, fasc. 6, p. 805-811, 1 pl. (1). vachard, d. & razgallah, s. (1993): d i s c u ssion sur l’âge murgabien ou midien des séries permiennes du jebel tebaga (sud de la tunisie).rivista italiana di paleontologia e stratigrafia, milano, vol. 99, n° 3, p. 327-356, 3 pl. (1-3). vachard, d., termier, h. & termier, g. (1977): la transgression viséenne au jebel goulib (maroc central).bulletin mensuel de la société linnéenne de lyon, lyon, 46° année, n° 8, p. 267281, 3 pl. (1-3). v e l i ∆, i. & s o k a » , b. (1982): novi nalazi naslaga donjeg i srednjeg trijasa u zapadnom kordunu (sre193granier & grgasoviê: les algues dasycladales du permien et du trias... diπnja hrvatska) [new discoveries of the lower and middle triassic in western kordun (central croa t i a )].geoloπki vjesnik, zagreb, svezak 35, p. 4757, 4 pl. h.-t. (i-iv). villa, f. (1961): su alcune microfacies dell’ afghanistan occidentale.rivista italiana di paleontologia e stratigrafia, milano, vol. lxvii, n° 4, p. 393-404, 2 pl. h.-t. (xxxi-xxxii). weidlich, o., bernecker, m. & flügel, e. (1993): combined quantitative analysis and microfacies studies of ancient reefs: an integrated approach of upper permian and upper triassic reef carbonates (sultanate of oman).facies, erlangen, 28, p. 115-144, 4 pl. (29-32). wendt, j. (1996): aragonitic dasycladalean algae from the upper permian of sichuan, china.lethaia, oslo, vol. 29, p. 361-368. wilson, j.l. (1975): carbonate facies in geologic history.springer-verlag, berlin, 471 p., 30 pl. (ixxx). wirz, a. (1945): xv. beiträge zur kenntnis des ladinikums im gebiete des monte san giorgio.in: peyer, b. (ed.): die triasfauna der tessiner kalkalpen. schweizerische palaeontologische abhandlungen, basel [mémoires suisses de paléontologie, bâle], band 65 (1944-1947), p. 1-84, 3 pl. h.-t. (7476). wolff, h. (1967): zur rät-fazies des östlichen wendelstein-gebietes (bayerische alpen).mitteilungen der bayerische staatssammlung für paläontologie und historische geologie, münchen, heft 7, p. 227243, 1 pl. (9, fig. 2-4). wolff, h. (1973): fazies-gliederung und paläogeographie des ladins in den bayerischen kalkalpen zwischen wendelstein und kampenwand.neues jahrbuch für geologie und paläontologie, abhandlungen, stuttgart, band 143, heft 2, p. 246-274. wray, j.l. (1977): calcareous algae.elsevier, developments in palaeontology and stratigraphy 4, amsterdam, 185 p. wright, v.p. (1982): uraloporella kordé from the lower carboniferous of south wales.bulletin of the british museum (natural history), geology, london, vol. 36, n° 2, p. 151-155. wu, y.-s. (1991a): calcareous algae from permian reefs of longlin, guangxi, china.acta palaeontologica sinica, beijing, vol. 30, n° 6, p. 750-767, 4 pl. h.-t. (i-iv). wu, y.-s. (1991b): organisms and communities of permian reef of xiangbo, china.international academic publishers, beijing, 192 p., 26 pl. (1-26). wurm, d. (1982): microfazies, paläontologie und palökologie der dachsteinriffkalke (nor) des gosaukammes, österreich.facies, erlangen, 6, p. 203-296, 15 pl. (27-41). yabe, h. (1949): 12. a new fossil dasycladaceae from the lower permian of china.japan academy, proceedings, tokyo, vol. xxv, n° 2, p. 61-63. zagorodnjuk, p.a. (1979): vodorosli. algae. in: einor, l.d. (ed.), atlas fauny i flory srednegopozdnego karbona bashkirii.ministerstvo neftjanoj promyshlennosti sssr, proizvodstvennoe ob’edinenie “bashneft”. nedra, moskva, p. 6-12 & 127, 3 pl. h.-t. (i-iii). zanin buri, c. (1965a): il trias in lombardia (studi geologici e paleontologici). xiii. le alghe calcaree delle prealpi lombarde.rivista italiana di paleontologia e stratigrafia, milano, vol. 71, n° 2, p. 449544, 23 pl. (42-64). zanin buri, c. (1965b): a new permian e p i m a s t o p o r a (calcareous alga) from hunza valley (western karakorum).in: amiot, m., ciry, r., fantini sestini, n., premoli silva, i., rossi ronchetti, c., sartenaer, p., vandercammen, a., schouppé, a. v o n & zanin buri, c.: vol. i, ist part: fossils of karakorum and chitral.in: italian expeditions to the karakorum (k2) and hindu kush, scientific reports. iv paleontology zoology botany, vol. i. e.j. brill, leiden, p. 79-88, 2 pl. h.-t. (8-9). zaninetti, l., brönnimann, p., huber, h. & moshtaghian, a. (1978): microfaciès et microfaunes du permien au jurassique au kuh-e gahkum, sud-zagros, iran.rivista italiana di paleontologia e stratigrafia, milano, vol. 84, n° 4, p. 865-896, 7 pl. (84-90). zawidzka, k. (1975): conodont stratigraphy and sedimentary environment of the muschelkalk in upper silesia.acta geologica polonica, warszawa, vol. 25, n° 2, p. 217-256, 44 pl. (1-44). zorn, h. (1971): xxi. paläontologische, stratigraphische und sedimentologische untersuchungen des salvatoredolomits (mitteltrias) der tessiner kalkalpen. unter besonderer berücksichtigung der mikrofazies, diagenese und taxionomie der lamellibranchiata.in: kuhn-schnyder, e. & peyer, b. (eds.): der triasfauna der tessiner kalkalpen. schweizerische paläontologische abhandlungen, basel, vol. 91, p. 1-90, 17 pl. (1-17). zorn, h. (1972a): mikrofazielle analyse eines mitteltriassischen riffkomplexes in den tessiner kalkalpen.in: mikrofazies und mikrofauna der alpinen trias und deren nachbargebiete (symposium innsbruck, 20.-23. märz 1972). mitteilungen der gesellschaft der geologieund bergbaustudenten in österreich, innsbruck, band 21, teil 1, p. 123-142, 3 pl. (i-iii). zorn, h. (1972b): bau und funktion der wirteläste einiger triassischer dasycladaceen (kalkalgen).194 geologia croatica 53/1 neues jahrbuch für geologie und paläontologie, monatshefte, stuttgart, heft 12, p. 727-740. zorn, h. (1974): variationsstatistische untersuchungen an diplopora annulata (s c h a f h.) und d . p h i l o s o p h i (p i a), kalkalgen der alpinen mitteltrias.eclogae geologicae helvetiae, basel, vol. 67, n° 1, p. 1-30, 2 pl. h.-t. (i-ii). zorn, h. (1977): der einfluß der umwelt auf die variation fossiler arten.natur und museum, frankfurt am main, 107, p. 1-5. manuscript received march 22, 1999. revised manuscript accepted may 19, 2000. 195granier & grgasoviê: les algues dasycladales du permien et du trias... introduction work continues on the third part of the “reappraisal of the fossil dasycladalean algae” published by granier & deloffre (1995) which deals with the permian and triassic representatives of this group. in that review, each and every dasycladalean algae known at the time are listed; the main taxononic problems are highlighted and some solved; finally the stratigraphic range of the subsequent valid taxa was drawn up. that preliminary study is part of a broader survey, namely the petralga project (permian and triasic algae), whose goal is to achieve an exhaustive report on the permian and triassic algae (granier, 1993). in order to further the study, the aim here is to review in a consistent way every available piece of information. consequently, the data file is based on the two “inventories” of fossil algae, published approximately 20 years ago concerning the carboniferous and permian algae (emberger, 1976), and the triassic algae (emberger, 1979). however, unlike emberger, we have selected references with illustrations (for comparision and checking), and those references dealing with taxonomic problems. more than 600 published papers and books have been screened, more than double that quoted by our honorable predecessor. special attention has been paid to the following: correct citation of bibliographic references; validity of the taxon; the type material; precise stratigraphic and geographic position with use of standardized names throughout the synonymy list; and possible discrepancies between the text and plate descriptions. in many cases we also paid attention to the correct determination of the particular specimen, marking “?” in the synonymy list for the questionable and “non” for incorrect determinations. historical review with statistics processing of data presented in our work enabled us to add some comments and suggestions. fig. 1 shows the development of research on the permian and triassic dasycladales. three stages of development can be recognized. the first stage comprises the early years of research, with the first papers on triassic dasycladales appearing in the 1850’s and for permian dasycladales in 1900’s, up until world war ii. the first researchers on the permian and triassic dasycladales include: schafhäutl (1853-1867), schauroth (18551859), stoppani (1857-1865), gümbel (18721874), benecke (1876-1898), salomon (1895), schubert (1907-1909), karpinsky (1909a, b) , and others. this stage is connected with the name of julius von pia (1912-1943), undoubtedly one of the most important researcher of fossil algae, particularly of forms from this stratigraphic interval. the second stage is marked by a great increase in interest on this fossil group after world war ii. many new researchers appeared, among them: johnson (1942-1969), herak (1950-1967), kordé (19501965), endo (1951-1969), konishi (1952-1959), kochansky-devidé (1955-1984), elliott (1956-1982), kulik (1956-1978), bystrický (1957-1986), horiguchi (1957-1961), panti∆ (1959-1997), milanovi∆ (1962-1986), ott (1963-1975), flügel (1963-1999), soka» (19641998), güvenç (1965-1979), and others. stage three (from the early 1970’s to the present), comprises a period of still high number of papers (with decreasing trend), but low and decreasing number of new taxa. there have been fewer new authors, including: zorn (1971-1978), mamet (19731996), chuvashov (1974-1993), mu xi-nan (1974-1984), vachard (1974-1997), roux (1975-1989), senowbari-daryan (1978-1993), de castro (1979-1997), di stefano (19811991) and others. there are probably two reasons for this interesting trend. it can be assumed that the most common permian and triassic species have already been discovered, so the following papers usually just quote their appearance and add new comments. the second reason might be the strong development and rise in popularity of sedimentology and sequence stratigraphy, leaving micropaleontological investigations in the background, and using algae only as facies indicators or in microfacies analysis. it also seems that, among phycologists, permian and triassic strata have lost their popularity during recent decades in favour of their younger counterparts. the skewness apparent in fig. 1 suggest a dark future for the research of permian and triassic dasycladales: the number of new species may drop to zero! we hope that new researchers will come, and the present ones will increase their scientific efforts, to stop this negative trend and enter a new stage of research in the new millennium. in the permian period 39 valid genera have been described, together with six more that are nomina nuda (homonyms or based on the type species without clear indication of the type “syntypes”), but which can be easily validated. that makes 45 permian genera, among permian and triassic dasyclad algae bibliographic, geographic, and stratigraphic reappraisal 196 geologia croatica 53/1 which are 21 monospecific ones (47%). nine genera are present in both the permian and the triassic. in the triassic period 20 valid genera existed, four of them being monospecific (20%). it is also worth mention that six valid genera (four in permian, two in triassic) are considered younger synonyms. the permian genera comprise 155 valid species, as well as 58 which could possibly be validated (forms erroneously ascribed to non valid genera, forms without a clear indication of type, and homonyms). the triassic genera comprise 93 valid species, as well as seven which may be validated. there are also 32 species (8 permian, 24 triassic) that are considered younger synonyms. among the accepted varieties there are only two in the permian, but 23 in the triassic, most of them included in the genera oligoporella and physoporella . nine genera span the permo-triassic boundary. however, none of the 144 species (i.e. 46% of the total number of the species from the permian-triassic range) from these genera span the boundary. moreover, no alga has been found in the lower triassic (barattolo, 1991; flügel, 1991; berger & kaever, 1992; granier & deloffre, 1994; bucur, 1999). from this data several conclusions on the development of this group of algae can be drawn. for example, the number of species per time interval in the permian was much higher than in the triassic, but the number of species per genus was much lower. however, some additional statistics suggest caution. besides the 213 permian species that are valid or can easily be validated, 111 of them (52%) have been found in only one locality (82 in the permian of japan and thailand). on the other hand, among the 100 triassic species, 30 of them (30%) have been found at only one locality. there are also some differences between authors that can be noticed in their application of taxonomic criteria, and in the way of interpretating morphological differences between specimens of algae. for example: one author has 17 titles cited in this paper, and she established one new species, whereas another author described 18 new species in his single paper. there are many additional examples. to help achieve a better understanding of the evolutionary changes of these algae, one of the goals of the petralga project is to verify the taxonomic justifiability of the establishment of particular species, and the presence of possible synonyms. taxonomic remarks as in granier & deloffre (1995), the focus here is on the taxonomic data, especially when referring to the types. the types are indeed the only definitive elements related to the species names. we also include the informations of the paratypes and, when it was known, to the type-material location. for most of the publications prior to 1912, the synonymy list was mainly based on the lists from pia’s papers. analysis of the older papers with only schematic or poorly reproduced illustrations, and incomplete descriptions, often based on taxonomically unimportant details, make these taxons problematic ones and raise questions. in addition most late 19th early 20th century collections are either considered definitely lost or temporarily (?) unavailable. thus, as far back as 1912, gümbel’s collection had been unavailable to pia. the most obvious case is illustrated by g y r o p o r e l l a a m p l e f o r a t a gümbel 1874. this species was only known through a brief description by its author and it was only later illustrated by pia (1912). we are now entitled to question the identity of these two forms separated by some 40 years of meandering palaeontology. finally, regarding the doubt cast on this name, this species should rather be called gyroporella amplefora ta gümbel ex pia 1912. there have been a series of uncertainties regarding the concept of genus, species, subspecies, variety, or form within the diplopora annulata group. table 1 depicts these changes in acceptance, from pia (1912, then 1920) to herak (1957) and finally güvenç (1979). according to the latest revision we confirm that diplopora septemtrionalis (pia 1920) güvenç 1979 is to be regarded as a nomen nudum due to the fact that its type-material is already attached to diplopora annu l a t a (schafhäutl 1853) 1863. as shown in table 1, pia (1920) included the already established species diplopora debilis (gümbel 1872) pia 1912 a n d kantia dolomitica pia 1912 as varieties within the species diplopora annulata (schafhäutl 1853) 1863. for the type variety he established the new name diplo pora annulata var. s e p t e m t r i o n a l i s, which is a n o m e n n u d u m, since the name of any infraspecific taxon that includes the type of the species to which it is assigned is to repeat the specific epithet (autonym, art. 26.1. icbn). this fact had been already recognized by byst r i c ký (1964) who corrected the variety name into diplopora annulata var. a n n u l a t a , retaining the threevariety division of the species. within each mentioned variety pia (1920) separated two forms on the basis of the shape of the branches (pores): “forma trichophora” and “forma vesiculifera”. on the other hand, herak (1957) concluded that differences in the shape of the branches are the most evident and constant characters, and instead of forms he established two subspecies and cancelled the varieties. the subspecies which is based on the type material, he named, in accordance with the icbn, diplopora annulata subsp. annulata . eventualy, in his revision of metaspondyl dasycladales, güvenç (1979) considered the shape of the branches as the main criteria to distinguish the genera diplopora and kantia . in the list of diplopora species he, however, quoted diplopora annulata, as well as diplopora septemtrion alis (obviously raised from variety to species level), which is actually the same, except that the first name is valid and the second is not. it should also be mentioned that we do not intend to make any taxonomic changes in the present study (new combinations etc.), but these will comprise a later stage 197granier & grgasoviê: les algues dasycladales du permien et du trias... of the petralga project. as a consequence there appear some inconsistencies in the synonymy list, mainly concerning the generic attribution of the species. for example, several species with metaspondyl arrangement of the branches were not mentioned in the revision of güvenç (1979), including: kantia monre galensis baretti 1919, diplopora proba pia 1935, diplopora permica kordé 1965, diplopora cellulata hurka 1967 nom. nud., diplopora borzai b y s t r ic ký 1978, etc., and consequently may have the incorect generic attribution. also some authors created new genera, for example anisoporella b o t t e r o n 1962 and euteutloporella de castro 1993, but non of the already known species that fulfil generic diagnostic criteria (except the type-species), were included. geographic and stratigraphic distributions we have followed one of the main principles of emberger’s “inventories”, i.e. that localities and stratigraphic positions of each find are indicated, therefore allowing one to better constrain the geographic distribution and the stratigraphic range of these algae. a few cases needed the name and geopolitical status of their localities to be updated: for instance, pontafel and neumarktl, both austrian in gümbel’s time, are nowadays respectively called pontebba and træië, the first being situated in the italian province of friuli venezia giulia, and the second in slovenia. for the permian system, according to faunal provinces (fusulinids) and to authors, several types of subdivision have followed one another or even coexisted. in the following we have adopted the threefold division: early permian (asselian, sakmarian, yahtashian, and bolorian stages in the tethys realm / asselian, sakmarian, artinskian, and kungurian stages in the urals), middle permian (kubergandian, murgabian, and midian stages in the tethys realm / ufimian and kazanian stages in the urals), late permian (dzhulfian and dorashamian stages in the tethys realm / tatarian stage in the urals). to allow for differences in authors perceptions, the qualifiers of the subsystems will eventually be addressed in inverted commas: for instance, the “late” permian of the united states of america, which corresponds in most cases solely to the guadalupian, is likely to represent middle to basal upper permian layers. on the contrary, the triassic system is classically tripartite: early triassic (scythian stage), middle triassic (anisian and ladinian stages), late triassic (carnian, norian, and rhaetian stages). conclusion beside probably serving as an “at hand” data base, and collection of information which would otherwise be difficult to access (old papers, papers printed in “exotic” journals, etc.), we hope that our contribution would encourage interest in these algae, the problems of their taxonomy, stratigraphic and geographic distribution, or their evolution. we also hope that our contribution will be helpful not only for people studying fossil dasycladaleans, but also other palaeontologists, stratigraphers and other geo-specialists dealing with permian and triassic strata. this work is a forerunner of the next step of the project, which is presently under construction on a free web site (referred as http://www.angelfire.com/fl3/ alga2000). it will consist of a general catalogue with some similarities to the one published by bassoullet et al. (1978) concerning the “jurassic and cretaceous dasycladalean algae”. ideally, by the end of the project, this catalogue will include all data available on the permian and triassic species: diagnostic elements (possibly revisions), photographs of the type material, geographic and stratigraphic distributions, etc. in order to develop a useable tool towards the recognition of these algae, and their biostratigraphic and palaeo-environmental applications. acknowledgments we wish to express our most sincere thanks to the numerous people who have encouraged and helped in compiling this inventory. special thanks to: j.c. b r ag a (granada univ., spain), i.i. b u c u r ( c l u j n a p o c a univ., romania), r. d e l o f f r e (pau, france), b. ferré (saint étienne du rouvray, france), p. génot (nantes univ., france), t. h o f m a n n ( g e o l ogische bundesanstalt, wien, austria), z. kotańs k i (panstwowy instytut geologiczny, warszawa, poland), m.-a. lançon (paris vi univ., france), j.-p. masse (elf, pau, france), late m. milanovi∆ (zagreb, croatia), b. soka» (institute of geology, zagreb, croatia), d. v a c h a r d (villeneuve d’ascq univ., france), and other colleagues from the petralga project. gratitude also goes to the editor of geologia croatica i. veli∆ for the opportunity to print this voluminous contribution, as well as to the technical editor i. vlahovi∆ for his careful technical polishing of the article. 198 geologia croatica 53/1 2020 | 73/1 | 13–28 | 11 figs. | 2 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society landslide types in the slani potok gully, croatia petra jagodnik1, vedran jagodnik1, željko arbanas1 and snježana mihalić arbanas*,2 1 faculty of civil engineering, university of rijeka, hr-51000 rijeka, croatia 2 faculty of mining, geology and petroleum engineering, university of zagreb, hr-10000 zagreb, croatia; (*corresponding author: smihalic@rgn.hr) doi: 10.4154/gc.2020.04 abstract the slani potok gully (0.48 km2) is situated in the central part of the vinodol valley (64.57 km2) in croatia, and it was formed in the eocene flysch deposits. so far, the area of slani potok has been mainly referred in the scientific literature as being subjected to unusually intense soil erosion processes (i.e., ‘’excessive erosion’’), associated with landslides. however, the landslides were never investigated in detail, given the available research methods only involved field investigations. therefore, the landslide types according to the most commonly used landslide classifications have remained undetermined. in this paper, landslide types in the slani potok gully are presented, identified and mapped based on the visual interpretation of seven different lidar topographic derivatives computed from the 1 x 1 m dtm available from march 2012. the geomorphological historical landslide inventory of the slani potok gully was created, consisting of 181 landslide phenomena. landslides cover 69 % of the area (0.33 km2) of the slani potok gully. the size of the smallest landslide is 65 m2, and of the largest is 10,563 m2. landslides are very small to moderate-small, shallow to moderate-shallow, and mainly successive in distribution. most of the landslides initiate along the margins of the gully channel walls, and extend to the gully channel bottom. such a large number of identified landslides, as well as their specific spatial arrangement within the gully, indicates that sliding processes predominantly affect the morphologic development of the slani potok gully, and that the soil erosion is the secondary process in the study area. article history: manuscript received may 21, 2019 revised manuscript accepted january 28, 2020 available online february 29, 2020 keywords: landslide classification, lidar derivatives, visual interpretation, historical landslide inventory, slani potok, vinodol valley ence of swelling minerals, sodium rich pore water, and the occurrence of the mineral thenardite (na2so4) (jurak et al., 2005), which has been documented as the first discovery of this mineral in croatia (mileusnić et al., 2004). thenardite was also observed in the eocene flysch bedrock in the upper part of the slano blato landslide (košir et al., 2013) located in the vipava valley in slovenia, which is characterized by geological conditions simi­ lar to the geological conditions in the vinodol valley. landslides and soil erosion, as well as the engineering geological conditions in the slani potok area have been investigated since the middle of the last century. historical data about landslides can be found in several important engineering geological and geotechnical reports that provide information about materials and geological contacts between the superficial deposits and the bedrock (e.g., domjan, 1965; biondić & vulić, 1970; štajduhar, 1976), or propose a review of suggested remedial measures (e.g., tomić et al., 1977). domjan (1965) has reported the first detailed data on flysch bedrock and superficial deposits, based on rotary drilling of 15 boreholes in the area of the county road 5064 passing along the border of the slani potok gully in its upper part. biondić & vulić (1970) have created the first engineering geological map at a scale of 1:5,000 of the slani potok and mala dubračina area, based on the results of rotary dril­ ling and detailed field investigations. although this map provides valuable information about superficial deposits in the study area, it doesn’t indicate locations and boundaries of individual landslide phenomena, but only depicts the entire areas affected by active and dormant landslides. more recent engineering geological data about landslides activated in the slani potok gully and its wider area can be found in đomlija et al. (2019b), as well as in several geotechnical design documents for landslide remediation purposes (e.g., arbanas, 2000, 2002; grošić, 2013). 1. introduction landslides play an important role in the evolution of landforms (crozier, 2010). they represent a serious hazard in many parts of the world (guzzetti et al., 2012), often as an element of multiple­hazard events (schuster & kockelman, 1996). economic losses caused by landslides can be significant and continuously increasing, especially in developing urbanized areas. despite the importance of landslides for the local communities and policies, it has been estimated that landslide maps cover less than 1% of the slopes in the landmasses, and that systematic information on landslide types, their spatial distribution and statistics is lacking (guzzetti et al., 2012; mihalić arbanas & arbanas, 2014). the preparation of landslide inventories, which can provide information about the locations of individual landslide phenomena of certain types (guzzetti, 2006), represents the preliminary step in landslide susceptibility, hazard and risk assessment (guzzetti et al., 2012). nevertheless, the knowledge of landslide types and understanding their socioeconomic significance for a particular area can facilitate rational decision making with regard to landslide prevention, control and mitigation (schuster, 1996; clague & roberts, 2012). the slani potok gully (0.48 km2) is situated in the central part of the vinodol valley (64.57 km2), in the north-western coastal part of the republic of croatia. the gully was formed in the eocene flysch deposits, which are mainly composed of marls, siltstone and sandstone (blašković, 1999). the area of slani potok is characterized by unusually intense erosion processes (aljinović et al., 2010), which have been commonly termed ‘’excessive erosion’’ in the scientific literature (e.g., benac et al., 2005; jurak et al., 2005). such erosion, associated with sliding processes (benac et al., 2005; aljinović et al., 2010), occurs due to the lithological composition of the flysch deposits, the presg eo lo gi a c ro at ic a geologia croatica 73/114 despite the fact that the sliding processes in the slani potok gully have been known and studied for more than 50 years, the landslide types according to the most commonly used landslide classifications (e.g., varnes, 1978; cruden & varnes, 1996) have still remained undetermined. this is probably due to the availability of only conventional methods for landslide investigations, i.e., geomorphological field mapping and visual interpretation of stereoscopic aerial photography, the application of which is limited to the production of detailed landslide inventories in morphologically complex and densely forested areas (guzzetti et al., 2012), such is the vinodol valley (caen, 2008). in the last two decades, analysis of surface morphology from the high resolution (hr) digital terrain models (dtms) created from lidar (light detection and ranging) data (wehr & lohr, 1999; razak et al., 2011; jaboyedoff et al., 2012) are effective in landslide inventory mapping (guzzetti et al., 2012). one of the leading methods used for the identification and mapping of landslides is the visual interpretation of hr lidar topographic derivatives (scaioni et al., 2014), which enables the effective mapping of relatively large rotational slides and complex failures (e.g., haugerud et al., 2003; van den eeckhaut et al., 2007; kasai et al., 2009; popit, 2017), small and shallow rainfall­induced landslides (e.g., ardizzone et al., 2007; bernat gazibara et al., 2019), and debris flows (e.g., haugerud et al., 2003). landslide mapping is effective in large forested areas (e.g., van den eeckhaut et al., 2007; petschko et al., 2016), smaller cultivated (e.g., ardizzone et al., 2007) and urbanized areas (e.g., mihalić arbanas, et al., 2016; bernat gazibara et al., 2019). the visual interpretation is mainly performed using the hillshade map, the slope map, and the contour line map (e.g., haugerud et al., 2003; ardizzone et al., 2007; van den eeckhaut et al., 2007; bell et al., 2010; petschko et al., 2016), although other lidar derivatives (i.e., maps) proved to be effective in landslide mapping, such as the curvature map (e.g., amundsen et al., 2010), or topographic roughness map (e.g., popit & ver bov­ šek, 2013; popit et al., 2016; bernat gazibara et al., 2019). the vinodol valley was a pilot area of the croatian­japanese scientific project risk identification and land­use planning for disaster mitigation of landslides and floods in croatia conducted from 2009 to 2014 (mihalić & arbanas, 2013). for the whole valley area, airborne laser scanning (als) was perfomed in march 2012 using the multi­return lidar system and the dtm at 1 x 1 m resolution was created, which opened up the opportunities for systematic and detailed scientific investigations of geomorphological processes in this area. the first landslide inventory map for the area of the du bra­ čina river basin in the vinodol valley, which also includes the slani potok gully, was created by toševski (2013) based on field geomorphological mapping coupled with the visual interpretation of hr lidar dtm. for this purpose, three types of topographic datasets (i.e., the hillshade map, the slope map and the contour line map with 1 metre contour interval) are derived from the dtm. a total of 39 landslide phenomena were identified in the dubračina river basin, including 20 landslides located in the slani potok gully. a total of 16 landslides are visually identified on lidar derivatives. despite the fact that a recent and new landslide mapping technique (guzzetti et al., 2012) was applied in this study, and that for each delineated landslide the dimensions and geometry are determined, the types of landslide processes occurring in the dubračina river basin have not been specifically determined. landslides in toševski (2013) are classified only based on their size, according to the classification of landslides proposed by šestanović (2001). this paper presents landslide types in the slani potok gully, which are identified and mapped based on the detailed visual interpretation of seven different lidar derivatives available from march 2012. landslides are classified according to the newest classification of landslide types proposed by hungr et al. (2014), who modified and updated the varnes landslide classification system (varnes, 1978), mainly in relation to the definition of landslide­forming materials. the significance of this study is the geomorphological historical landslide inventory of the slani potok gully that shows the individual boundaries and spatial arrangement of 181 past and current landslides, classified according to recent advances in the understanding of landslide phenomena, as well as the relevant materials and mechanisms (hungr et al., 2014). these new findings related to landslide types and their spatial arrangement can certainly contribute to the local sustaina­ ble development, as well as to a better understanding of the morphological evolution of the slani potok gully. 2. study area the slani potok gully is located in the vinodol valley (64.57 km2), which is situated in the north-western coastal part of the republic of croatia (fig. 1a). the gully is located in the central part of the vinodol valley, i.e., in the dubračina river basin (fig. 1b), and covers an area of 0.48 km2 (đomlija, 2018). the gully was formed within the populated rural area, and it is surrounded by several settlements and roads (fig. 1c and d). the county road cr 5064 passes along the border of the gully channel in its upper part, in which the badlands are formed (fig. 1d), and this road has often been damaged due to the influence of active geomorpho­ logical processes. county road cr 5089, which passes along the dubračina riverbed in the middle part of the valley (fig. 1c), is connected with the county road cr 5064 by several local roads passing through the settlements situated along the lateral margins of the slani potok gully channel. delineation of the slani potok gully is performed during the preparation of the historical erosion inventory of the vinodol valley (đomlija, 2018), which depicts past and current soil erosion phenomena identified and mapped based on the detail visual interpretation of eight types of hr lidar 1 x 1 m topographic derivatives. the methodology, as well as the lidar derivatives used for identification and mapping of soil erosion processes in the vinodol valley, which was also applied to delineation of the slani potok gully, is presented in detail in đomlija et al. (2019a). the slani potok gully is the largest gully phenomenon formed in the vinodol valley (đomlija, 2018). according to the classification of gullies based on gully dimensions (frevert, 1955), and the relative age and stage of gully growth (kostenko, 1975), the slani potok gully can be classified as a large and relatively old gully, characterized by great length, marked branching of the gully channel and a detrital cone located at the gully mouth. the classification of gully types for the area of the vinodol valley is proposed by đomlija (2018), based on the degree of development of the gully drainage network determined according to strahler (1952, 1957), and the morphological characteristics of the gully channel. according to these criteria, the slani potok is a complex gully (đomlija, 2018), with a branched gully channel the shape of which is mostly deg eologia c roatica jagodnik p. et al.: landslide types in the slani potok gully, croatia 15 fined by the third­order stream network of the main gully channel that has been extended by the second­order and first­order drainage channels (fig. 1c). numerous landslides activated within the slani potok gully have significantly contributed to its morphological evolution. the main part of the gully area is covered by forest vegetation, as are most of the surrounding slopes (fig. 1d). the forests cover an area of 32.19 km2 in the vinodol valley (caen, 2008). the climate is maritime (zaninović et al., 2008), with mean annual precipitation between 300 and 700 mm. the rainy season lasts from november to may, with precipitation at its maximum in november when rainstorms of high erosive potential frequently occur. the steep flanks of the vinodol valley (fig. 1d) are composed of upper cretaceous and palaeogene carbonate rocks (šušnjar et al., 1970; blašković, 1999), while the lower parts and the bottom of the valley are built of a palaeogene flysch rock mass, mainly composed of marls, siltstones and sandstones in alteration. however, the flysch bedrock is mostly covered by various types of superficial deposits formed by geomorphological processes active both in the carbonate and flysch rock mass (bernat et al., 2014; đomlija et al., 2014). a detail from the engineering geological map 1:25,000 (đomlija, 2018), which was created based on the visual interpretation of hr lidar ima­ gery, is shown in figure 2. older and recent talus deposits have been accumulated at the foot of the limestone cliffs, as a result of different types of mass movements, predominantly of rock falls, rock topples, and irregular rock slides (đomlija, 2018). large, individual limestone boulders have been transported to the hypsometrically lower parts of the cliff foothills, probably as a result of larger rock falls and debris avalanches. breccias have an irregular, patchy occurrence and they are characterized by the different sizes and shapes of the sedimentary bodies. flysch bedrock in the central part of the vinodol valley is mostly covered by the hillwash and older talus deposits, mainly composed of clays ranging from high plasticity clays to gravely clays (pajalić et al., 2017), mixed in different ratios with the rock fragments from limestone and flysch. due to gravitational transport and mixing figure 1. geographical location of the vinodol valley (a); geographical location of the slani potok gully within the vinodol valley, with the spatial coverage of the dubračina river basin and the suha ričina basin (b); geomorphology of the slani potok gully on the hillshade map derived from lidar dtm, with elements of drainage network determined according to strahler (1952, 1957) (c); and the aerial photograph of the dubračina river basin, photographed from the southeast to the northeast (d). g eo lo gi a c ro at ic a geologia croatica 73/116 of fragments, these soils can significantly vary in thickness, from less than one to several metres, and as well as in their physico­ mechanical properties across the study area (đomlija, 2018). flysch slopes have been dissected by several relatively large and deep gullies, such as the slani potok (0.48 km2), mala dubračina (0.31 km2) and kučina (0.15 km2) (fig. 2). within these gullies, the landslide deposits have been formed as a result of sliding processes. landslide deposits represent zones of acculumation of numerous landslides identified and mapped withing the gullies (đomlija, 2018), composed of weathered flysch bedfigure 2. a detail from the engineering geological map of the central part of the vinodol valley 1:25,000 (đomlija, 2018). g eologia c roatica jagodnik p. et al.: landslide types in the slani potok gully, croatia 17 rock, which represents a material lying at the contact between the soil and rock (pajalić et al., 2017). due to the sliding processes, flysch bedrock can sporadically crop out in the steep upper parts of the gully channel walls. the soil erosion processes have also been active within the gullies; so alluvial fan deposits are situa­ ted at the mouth of the gully channels, and they form the almost continuous sheet at the foot of the northwestern flysch slopes. eluvium mostly covers the bedrock in the hypsometrically lower parts of the flysch slopes. the hillwash deposits have been formed in places at the foot of the flysch slopes, by the recurring sheet erosion processes on the surface of the eluvium. alluvial fans and hillwash deposits partially cover the river alluvium deposites, located around the dubračina riverbed. 3. materials and methods 3.1. high resolution lidar data the lidar data used in this study were acquired in march 2012 by airborne laser scanning using the multi­return lidar system. the last returns (i.e., bare­ground returns) were acquired at the point density of 4.03 points per square metre, with an average point distance of 0.498 meters. these data were used for the creation of the dtm with a 1 x 1 m resolution, using a triangulated irregular network interpolation (mitas & mitasova, 1999). the average accuracy of the altitude data is 30 cm, but it may be lower in areas covered with dense vegetation. seven types of topographic datasets are derived from dtm using the standard tools in the arcgis 10.0 software, and they are used for the topographic analysis of the slani potok gully: (i) the hillshade map; (ii) the slope map; (iii) the contour line map; (iv) the topographic roughness map; (v) the profile curvature map; (vi) the planform curvature map, and (vii) the stream power index map. hillshade maps were created using the sun azimuth angles of 315° and 45°, and the sun elevation angles of 45° and 30°. the hillshade map with the sun azimuth angle of 315° and the sun ele­ vation angle of 45° (i.e., hillshade map 315°/45°) was used in the analysis in general, but in order to obtain the optimal shaded relief for each part of the studied area (e.g., van den eeckhaut et al., 2005) hillshade maps were overlapped in two combinations: (a) the semi­transparent (50 %) hillshade map 45°/45° over the hillshade map 315°/45°, and (b) the semi­transparent (50 %) hillshade map 45°/30° over the hillshade map 315°/45°. the slope map was reclassified into seven slope angle classes, according to igu (1968). the contour line map was created with 1­m contour intervals. the topographic roughness map was calculated according to the slope variability method (e.g., popit & verbovšek, 2013), where the slope variability implies a difference between the minimum and the maximum slope angle in the selected area. the input parameter for creation of the topographic roughness map was the slope map. first, the maximum slope angle raster (smax) and the minimum slope angle raster (smin) were generated, and the topographic roughness map, i.e., slope variability (sv) was then calculated as: sv s s= − max min the input parameters for the creation of the stream power index map were the slope map and the flow accumulation map. the stream power index map was calculated according to moore et al. (1991) as: spi flow accumulation slope = ×     ln( ) 100 (2) 3.2. delineation of landslides based on visual interpretation of hr lidar topographic derivatives discernible topographic characteristics remaining at the surface after a landslide occurrence, i.e., topographic signatures (rib & liang, 1978; antonini et al., 2002; guzzetti, 2006) depend on the landslide type (cruden & varnes, 1996), whereby the same type and rate of a mass movement results in a similar topographic signature (guzzetti et al., 2012). moreover, landslides do not occur randomly in an area (guzzetti et al., 2002), but are instead the results of the interplay of physical processes and mechanical laws which control the landslide size, shape and spatial evolution (crozier, 1986; cruden & varnes, 1996). the main features that have enabled recognition of topographic signatures specific for certain landslide features (varnes, 1978) in this study are: (a) shape; (b) morphometric characteristics; (c) texture; and (d) appearance. these recognition features are visually analysed on different lidar derivatives, as shown by the example of landslide identification and mapping in figure 3. landslides were first searched on the hillshade map (fig. 3a), because the hillshade map most clearly reflects the pseudo three­ dimensional effect of a surface (guzzetti et al., 2012). however, the topography of landslide features for a particular number of landslide phenomena in the study area is not clearly expressed on the hillshade map, as in the example shown in figure 3a. a semilunar crown (pointed with red arrows in fig. 3) can be, in most cases, easily recognized on the slope map (fig. 3b), the topo­ graphic roughness map (fig. 3c), and the profile curvature map (fig. 3d). although contours generally most clearly reflect the shape of the landslide crown (e.g., amundsen et al., 2010; petschko et al., 2016), this is not the case in the presented example (fig. 3b). abrupt changes in slope morphology, e.g., steep slope angles coupled with the slope concavity, are specific to the main scarp (pointed with blue arrows), and these morphometric characteristics can be easily recognized on the slope map (fig. 3b) for almost all landslides in the slani potok gully. for a particular number of landslides in this study, these recognition features could have been easily observed on the profile curvature map too. for most of the landslides, the flanks (pointed with black arrows) are best reflected by the rough texture (fig. 3c), convex slope morphology (fig. 3d), and partially by the contour lines (fig. 3b). the shape of a zone of accumulation (pointed with purple arrows) is mainly well expressed on the contour line map (fig. 3b). however, the planform curvature map (fig. 3e) and the stream power index map (fig. 3f) were particularly useful for the recognition and precise delineation of a zone of accumulation. a hummocky appearance, rough texture and frequent changes of curvature, which are specific for the landslide foot (pointed with cyan arrows), can be recognized on the slope map (fig. 3b), the topographic roughness map, and the profile curvature map (fig. 3d) for almost all the inspected landslides. the planform curvature map (fig. 3e), and the stream power index map (fig. 3f) also reflect the landslide toe (pointed with green arrows), while the slope map (fig. 3b), the topographic roughness map (fig. 3c), and the profile curvature map reflect the landslide tip (pointed with white and gray arrows), mainly in the cases of well preserved topography. landslides are mapped with polygons (fig. 3g) by one and the same expert according to established mapping criteria, which imply that certain recognition features are visually analysed on the most effective lidar derivatives (fig. 3). the recognition of landslide phenomena was performed by screening the lidar deg eo lo gi a c ro at ic a geologia croatica 73/118 rivatives on a scale between 1:1,000 and 1:5,000, relative to the size of the slani potok gully. however, the precise delineation of landslides was performed on considerably larger scales, mainly ranging between 1:100 and 1:300. the portions of individual landslide features are separately drawn on different lidar maps, depending on their visibility on each analysed lidar map. these separately drawn lines of landslide feature boundaries are subsequently merged into a unique polygon representing the landslide. 3.3. identification of landslide types landslides are classified according to the updated varnes classification of landslide types (varnes, 1978) proposed by hungr et al. (2014). the main objective of this recent classification system of landslide types is to modify the definitions of landslide­ forming materials, to provide compatibility with the accepted geotechnical and geological terminology of rocks and soils. the type of movement for each landslide is determined based on the shape of the delineated polygon, while the landslide depth is estimated based on the polygon size (cruden & varnes; 1996; soeters & van westen, 1996). the type of material is determined based on the reconnaissance geological mapping and from the engineering geological map of the vinodol valley 1:25,000 (đomlija, 2018), as well as the general knowledge of geological (domjan, 1965; biondić & vulić, 1970; šušnjar et al., 1970; blašković, 1999) and geotechnical conditions (arbanas, 2000, 2002; pajalić et al., 2017; đomlija et al., 2019b) in the study area. each polygon is assigned with the landslide identifier number, consisting of letters indicating the landslide type, and numbers indicating the ordinal number in order of landslide delineation. landslide dimensions are calculated using the standard tools in arcgis 10.0. the areas were automatically calculated, and the total lengths were manually measured. descriptive statistics for each landslide type (hungr et al., 2014) are calculated based only on the total number of completely identified landslides, i.e., landslides where the delineated polygons depict the entire landslide body. this approach in the statistical analysis was applied in order to obtain the realistic data set for determination of landslide dimensions characteristic for the slani potok gully. namely, the areas and lengths of delineated polygons of landslides with certain reactivated elements are smaller than they would be if the same landslides had not been reactivated. therefore, such polygons are excluded from the descriptive statistic analysis. the relative landslide age and the state of activity were not determined in this study. the main reason for this is the fact that the determination of these attributes is based on the overall appearance of the landslide topography on analysed imagery (mccalpin, 1984; wieczorek, 1984; keaton & degraff, 1996). in the case of the slani potok area, this is difficult to perform correctly because of the soil erosion processes active within the gully (e.g., jurak et al., 2005), which can significantly modi fy the landslide topography even in the case of recent landslide phenomena (e.g., malamud et al., 2004; bell et al., 2012). 3.4. field verification identification of landslides on lidar derivatives is partially veri­ fied by multiple field recognitions, which were mostly conducted during the winter and early spring of 2015 and 2016, in the vege­ tation leaf­off period. portions of individual landslides are identified in the field, where it was possible to recognize mainly the landslide crowns and main scarps, as well as to determine the landslide­forming materials. generally, field identification of landslide phenomena and their types identified on lidar maps is considerably limited for two main reasons, and thus the number of landslides that are also identified in the field is not expressed in this study. firstly, the study area is a large and branching gully (fig. 1c) characterized by relatively steep gully walls that are mostly cove­ red by dense forest (fig. 1d). therefore, only certain smaller gully portions in its upper denuded part (fig. 1d) can be accessed, from which the researcher can obtain a distant view of the landslides figure 3. an example of landslide features topography visible on hr lidar topographic derivatives: (a) the semi-transparent (50 %) hillshade map 45°/45° over the hillshade map 315°/45°; (b) the contour line map of 1 metre contour interval over the slope map; (c) the topographic roughness map; (d) the profile curvature map; (e) the planform curvature map; and (f ) the stream power index map; (g) delineated polygon representing landslide presented on the contour line map over the slope map. g eologia c roatica jagodnik p. et al.: landslide types in the slani potok gully, croatia 19 that is desirable for effective field recognition (guzzetti et al., 2012). from such spatially restricted positions, it is not easy for a researcher to quantify the landslide phenomena observed in the opposite gully channel wall, located at a considerable distance away. moreover, in the slani potok gully, a researcher can genera­ lly distinguish landslides only in their upper parts, while individual zones of accumulation, the characteristics of which are crucial for determination of the type of movement (soeters & van westen, 1996), are difficult to distinguish in the field. secondly, landslides in the slani potok gully are identified and mapped based on the remote sensing data collected in 2012, after which a certain number of landslide phenomena occurred in the study area. there are also erosion processes active in the slani potok gully, particularly in its denuded portion, where they continuously modify the landslide topography. therefore, it is not possible to straightforwardly validate the landslide inventory map prepared using the available lidar derivatives, given that a certain number of landslides in the slani potok gully are partially or totally modified by later landslides or erosion processes. however, the slani potok gully is a relatively small study area when considering the main assumptions for the preparation of a landslide inventory (guzzetti et al., 2012), and it represents a single geomorphological unit of uniform geological and morphological conditions. for such small study areas, the principle of uniformitarianism (varnes & iaeg, 1984) can be fully applied (guzzetti et al., 2012), unlike for larger study areas characteri­ zed by marked variations in the local slope conditions, where the necessity for field verification of the remote sensing results increases, and where it is commonly performed on 15 % of the area covered by a landslide inventory (galli et al., 2008). 4. results based on the visual interpretation of hr lidar topographic derivatives, two types of landslides (hungr et al., 2014) are identified in the slani potok gully: (a) debris slide; and (b) debris slide­ debris flow. 4.1. debris slide (ds) a debris slide (ds) represents the sliding of a veneer of colluvium or residual soil over a harder substrate on a shallow planar surface parallel to the ground (hungr et al., 2014). such translational sliding (cruden & varnes, 1996) generally results in an elongated shape of a landslide phenomenon (soeters & van westen, 1966). according to hungr et al. (2014), debris represents the unsorted and texturally mixed soil material originating from the weathering of bedrock which, if it is fine­ grained, is generally of low plasticity. specifically, the larger part of the slani potok gully is covered by the veneer of residual and colluvial deposits formed from the flysch bedrock, which are determined as debris material according to their origin, textural characteristics and geotechnical properties (e.g., domjan, 1965; biondić & vulić, 1970; đomlija et al., 2019b). debris slide phenomena in the slani potok gully are tipically activated along the contact between the flysch bedrock and superficial deposits, as well as along the contact of the residual and colluvial deposits. debris slides have been initiated both along the margins of the gully channel walls (fig. 4a to c), and within the inner parts of the gully channel (fig. 4d­f). certain landslide phenomena cause direct damage to local roads, as shown in fig. 4c; the local road in the kamenjak settlement affected by a landslide in february 2014. examples of debris slides representative of the study area on certain lidar maps used in the visual analysis are presented in fig. 5. there are significant differences in the visibility of landslide features on the hillshade map in all the presented examples. the topography of debris slides ds 32 (fig. 5a), ds 40 (fig. 5b) and ds 6 (fig. 5c) is clearly visible on the hillshade map. in contrast, the topography of debris slides ds 28 (fig. 5a), ds 36, ds 37, ds 38 (fig. 5b), ds 2 and ds 4 (fig. 5c) is not so clear on the hillshade map, while all debris slides shown in figure 5e are almost un­ recogniz able on the hillshade map. the topography of the largest debris slide ds 2 identified in the study area (a = 10,536 m2; l = 150 m), shown in fig. 5c, is relatively smooth, and it has been figure 4. photographs of debris slide phenomena identified in the slani potok gully: (a-c) debris slides activated along the edges of the gully channel walls, where the landslide shown in (c) was activated on the local road in the kamenjak settlement; (d-f ) debris slides activated within the inner parts of the gully channel. arrows in (d) and (f ) point to the crowns of debris slides. g eo lo gi a c ro at ic a geologia croatica 73/120 figure 5. examples of debris slide (ds) topography in the slani potok gully presented on (from left to right) the contour line map of 1-m contour interval over the slope map, the profile curvature map, and the semi-transparent (50 %) hillshade map 45°/45° over the hillshade map 315°/45° without, and with delineated landslide polygons: (a) ds 32 and ds 28; (b) ds 36, ds 37, ds 38 and ds 40; (c) ds 2, ds 4 and ds 6; (d) ds 75; and (e) ds 52, ds 54, ds 55 and ds 56. g eologia c roatica jagodnik p. et al.: landslide types in the slani potok gully, croatia 21 modified by artificial drainage channels. however, the slope map clearly reflects the topographic features of almost all debris slides, especially the crowns, main scarps, and zones of depletion. on the slope map, as well as on the profile curvature map, even the smallest debris slides (e.g., fig. 5d and e) can be easily recognized. debris slides predominantly have an elongated shape, such as those shown in fig. 5b and 5e. however, certain phenomena are characterized by widening of the landslide accumulation, such as the debris slides ds 32 (fig. 5a) and ds 6 (fig. 5c). there are 107 debris slide phenomena identified in the study area. their total area is 196,134 m2. of the total number of debris slide phenomena, 99 debris slide polygons represent completely identified landslides, which are used as a representative data set for the descriptive statistic analysis (tab. 1). the smallest debris slide has an area of 65 m2, and the largest has an area of 10,536 m2. however, 75 % of all the identified debris slides have an area < 2,355 m2. the maximum total length of debris slide phenome na is 174 m, with an average value of 66 m. according to the classification of landslides based on volume and depth proposed by icl (2018), debris slides identified in the slani potok gully represent very small to moderate­small, shallow to moderate­ shallow landslides, with estimated volumes in a range between < 103 and 105 m3 and estimated depths in a range between one and five metres. 4.2. debris slide-debris flow (dsdf) a debris slide­debris flow (dsdf) generally initiates as a shallow planar sliding, and the movement transforms into a flow after moving a relatively short distance (hungr et al., 2014). for a particular number of landslide phenomena in the slani potok gully, a relatively shallow planar sliding of debris material provides the source for a flow type of movement of limited extent. thus, the landslides are characterized by an elongated shape, given that displacement may extend over a considerable distance (soeters & van westen, 1996). flow features can gene­ rally be clearly recognized in the zone of accumulation of landslides, by the hummocky appearance of their lobate convex forms. an example of debris slide­debris flow phenomenon identified in the slani potok gully is presented in figure. 6. two types of debris slide­debris flow can be distinguished in the slani potok gully: (a) the a­type debris slide­debris flow, in which the displaced material flows to the gully thalweg and accumulates at the bottom of the gully channel (fig. 7a); and (b) the b­type debris slide­debris flow, in which the flow of the displaced material continues along the gully thalweg and infills the bottom of the gully channel (fig. 7b). examples of representative topography of an a­type debris slide­debris flow (dsdfa) on certain lidar maps are presented table 1. descriptive statistics for debris slides (ds) identified in the slani potok gully, calculated according to the number of completely identified landslides. no. of complete landslides total area (m2) landslide dimension avg min 25th percentile (q1) 50th percentile (q2) 75th percentile (q3) max 99 178,746 area, a (m2) 1,806 65 536 1,240 2,355 10,536 total length, l (m) 66 12 37 61 85 174 figure 6. an example of debris slide-debris flow phenomenon identified in the slani potok gully. g eo lo gi a c ro at ic a geologia croatica 73/122 in figure. 8. the phenomenon dsdfa 1 (fig. 8a) is characterized by the smoothed appearance on the hillshade map and the profile curvature map. however, almost all landslide features are clearly expressed on the slope map and the contour line map. the landslide has an elongated shape, with a total length of 136 m, and is generally narrow. the narrowing of the landslide body is more pronounced in the transition between the zone of depletion and the zone of accumulation. the morphological characteristics of the flow movement, e.g., the hummocky relief and lobate convex forms in the landslide foot (soeters & van westen, 1996) figure 7. simplified models representing the types of debris slide-debris flows identified in the slani potok gully: (a) the a-type debris slide-debris flow; (b) the b-type debris slide-debris flow. figure 8. examples of an a-type debris slide-debris flow (dsdfa) topography in the slani potok gully presented on (from left to right) the contour line map of 1-m contour interval over the slope map, the profile curvature map, and the semi-transparent (50 %) hillshade map 45°/45° over the hillshade map 315°/45° without, and with delineated landslide polygons: (a) dsdfa 1; and (b) dsdfa 9. g eologia c roatica jagodnik p. et al.: landslide types in the slani potok gully, croatia 23 are better expressed in the case of debris slide­debris flow dsdfa 9 (fig. 8b), the topography of which is almost entirely clearly recognizable on all lidar derived maps. this pheno­ menon also has an elongated shape, with a total length of 157 m. the direction of transport, and thus the slightly curved shape of the landslide accumulation, was predetermined by the presence of the adjacent landslide phenomenon ds 32. an example of a b­type debris slide­debris flow (dsdfb) with well preserved topography of all the landslide features is presented in figure 9a. the phenomenon dsdfb 21 (a = 5,262 m2; l = 212 m) can easily be recognized on the hillshade map, especially by the lobate convex accumulation infilling the bottom of the gully channel. such lobate forms, coupled with the transverse ridges, can be the most easily recognized on the profile curvature map and the contour line map. an elongated and mainly curved shape also characterizes the landslide phenomena shown in fig. 9b and 9c. the topography of the dsdfb 6 (a = 5,541 m2; l = 209 m) is generally smooth and thus poorly visible on the hillshade map. however, the main scarp and the right flank can be clearly recognized on the slope map, while the zone of accumulation can be recognized on the contour line map and the profile curvature map. in contrast, the topography of certain smaller landslides located between the county road cd 5064 and the local road toward the kamenjak settlement (fig. 9c) is almost entirely unrecognizable on the hillshade map. only the rough texture is visible on the hillshade map, as well as the main scarp of the landslide phenomenon dsdfb 23, which is partially covered by the foot of the phenomenon dsdfa 21. however, in the cases of all shown phenomena, accumulations are well expressed on the slope map and the profile curvature map. landslide sizes and shapes are predetermined by the existence of the drainage channels formed within the gully head, i.e., the paths of the displaced mass follow the gully thalwegs and thus they partially cover each other. there are 74 debris slide­debris flows identified in the slani potok gully. their total area is 145,226 m2. in total, 39 landslides are identified as an a­type debris slide­debris flow (total area of 70,466 m2), and 35 landslides are identified as a b­type debris figure 9. examples of a b-type debris slide-debris flow (dsdfb) topography in the slani potok gully presented on (from left to right) the contour line map of 1-m contour interval over the slope map, the profile curvature map, and the semi-transparent (50 %) hillshade map 45°/45° over the hillshade map 315°/45° without, and with delineated landslide polygons: (a) dsdfb 21; (b) dsdfb 6; and (c) dsdfb 19, dsdfb 23 and dsdfb 25. in (c), the landslide polygon of dsdfa 21 is also presented. g eo lo gi a c ro at ic a geologia croatica 73/124 slide­debris flow (total area of 74,760 m2). in total, 65 delineated debris slide­debris flows are defined as completely identified landslides, and they are thus used as a representative data set for descriptive statistic analysis (tab. 2). in the slani potok gully, the smallest debris slide­debris flow has an area of 154 m2, and the largest debris slide­debris flow has an area of 9,734 m2. an avera ge area of an a­type debris slide­debris flow is 1,877 m2, and 2,402 m2 for a b­type debris slide­debris flow. the average total length of an a­type debris slide­debris flow is 90 m, and 115 m for a b­type debris slide­debris flow. according to the classification of landslides based on volume and depth proposed by icl (2018), debris slide­debris flows in the slani potok gully represent very small to moderate-small, shallow to moderate-shallow landslides, with estimated volumes in a range between < 103 and 105 m3 and estimated depths in a range between one and five metres. 4.3. landslide inventory of the slani potok gully the landslide inventory of the slani potok gully consists of 181 dormant and active debris slide and debris slide­debris flow phenomena. according to the classification of landslide inventories (guzzetti et al., 2012), it is the geomorphological historical inventory type. the total mapped landslide area is 0.34 km2. one of the largest mapped debris slides (a = 10,160 m2) covers part of the area which is outside the slani potok gully (see fig. 11), so the total landslide area within the gully is slightly smaller: 0.33 km2. landslides cover 69 % area of the slani potok gully. the size of the most abundant debris slide in the landslide inventory is approx. 2,500 m2 (fig. 10a), and the size of the most abundant debris slide­debris flow is approx. 2,700 m2 (fig. 10b). landslides have mostly been activated along the margins of the gully channel walls (fig. 11). they are characterized by their similar, predominantly elongated shapes. for most of the landslides, the total length is approximately the same as the length of the gully channel walls, except for a certain number of debris slide­debris flows. debris slides have a more regular spatial arrangement along the gully channel, while most of the debris slide­ debris flows are located within the upper and middle parts of the slani potok gully. landslides have a predominantly successive distribution (wp/wli, 1993). certain debris slides have been reactivated within the zone of accumulation, and rarely within the zone of depletion. some landslides are partially to significantly covered with accumulations of adjacent landslides, particularly if they are located near the debris slide­debris flow phenomena. 5. discussion debris slides are the most abundant landslide type identified in the slani potok gully (107 phenomena of in total 181 mapped landslides), including the smallest (amin = 65 m2), and the largest slides (amax = 10,563 m2). the average size of the debris slide pheno­ mena (aavg = 1,806 m2) is approximately the same as the average size of the a­type debris slide­debris flows (aavg = 1,877 m2). the 75th percentile of the landslide area is also similar for debris slides (aq3 = 2,355 m2) and the a­type debris slide­debris flows (aq3 = 2,535 m2). the b­type debris slide­debris flows generally represent the largest landslides within the slani potok gully (aq3 = 2,738 m2), although the largest mapped phenomenon (amax = 9,734 m2) is smaller than the largest mapped debris slide (amax = 10,563 m2). the b­type debris slide­debris flows also have the maximum total length (lavg = 115 m), that is on average almost two times larger than the total length of debris slides (lavg = 66 m). the similar elongated shapes (fig. 11), as well as the similar dimensions of most identified landslides (tab. 2, 3), are predetermined by the gully shape and dimensions, given the fact that landslides are mostly activated along the margin of the gully channel walls and transported to its bottom. statistics indicate that the relatively large landslide phenomena, with a size table 2. descriptive statistics for debris slide-debris flows (dsdf) identified in the slani potok gully, calculated according to the number of completely identified landslides. debris flow-debris slide no. of complete landslides total area (m2) landslide dimension avg min 25th percentile (q1) 50th percentile (q2) 75th percentile (q3) max a-type 36 67,582 area (m2) 1,877 154 843 1,728 2,535 5,659 total length (m) 90 22 63 90 113 183 b-type 29 69,649 area (m2) 2,402 438 937 1,809 2,738 9,734 total length (m) 115 41 77 106 143 236 figure 10. frequency-size distribution of: (a) debris slide phenomena; and (b) debris slide-debris flow phenomena identified in the slani potok gully. g eologia c roatica jagodnik p. et al.: landslide types in the slani potok gully, croatia 25 greater than approx. 7,000 m2, are actually rare in the study area (fig. 10). relatively small landslide phenomena, particularly debris slides, with sizes less than approx. 300 m2, mainly represent the reactivated parts of older and larger landslides. there are significant differences in the visibility of landslide topography in the slani potok gully on lidar derivatives, especially on the hillshade map. in particular, a certain number of landslides are poorly visible (e.g., landslides shown in figs. 5b, 5c and 9c) to almost unrecognizable (e.g., landslides shown in fig. 5e) on the hillshade map. this is important to point out, considering that the hillshade map is commonly used as the first map (e.g., van den eeckhaut et al., 2007; ardizzone et al., 2007; petschko et al., 2016) or even as the only map (e.g., bell et al., 2012) within landslide studies based on the visual interpretion of hr lidar imagery. namely, if other lidar maps had not been simultaneously analysed in this study when visually searching for landslides, a certain number of landslide phenomena in the slani potok gully could have easily been omitted, given their poor visibility on the hillshade map. it must be emphasized, based on the experience in mapping landslides in this study, that using as many lidar maps as possible, both singularly and in combinations, to recognize and precisely delineate the boundaries of individual landslide features is important. specifically, certain lidar maps (e.g., the slope map, figure 11. landslide inventory map of the slani potok gully presented on the semi-transparent (80%) croatian base map 1:5,000 over the hillshade map derived from the lidar dtm. g eo lo gi a c ro at ic a geologia croatica 73/126 the profile curvature map, and the topographic roughness map) proved to be more useful for the delineation of landslide crowns, but not particularly useful in delineating the landslide accumulations. in the cases of many landslides identified in this study, the effectiveness of the contour line map in recognizing the crowns and flanks (e.g., fig. 3) has been reduced, although this map is generally considered as highly effective for recognition of these landslide features (e.g., van den eeckhaut et al., 2007; amundsen et al., 2010; petschko et al., 2016). the planform curvature map and the stream power index map, frequently coupled with the contour line map, were highly effective in the recognition and precise delineation of landslide accumulations and toes in this study. among all landslide features, the crowns and toes were the easiest to be delineated, because these features mainly coincide with certain elements of the slani potok gully. namely, most of the landslide crowns coincide with the upper margin of the gully channel (e.g., fig. 5a to c), which can easily be recognized on the slope map due to the well­defined changes of slope angle between the gully channel and the surrounding slopes. furthermore, the landslide toes mainly concide with the gully thalweg (fig. 10), which is almost entirely visible on the planform curvature map, and the stream power index map. in contrast, the flanks and accumulations were the most difficult to delineate precisely, considering that landslides are partially being eroded and that they are mostly successive and thus covered by accumulations of adjacent landslides (fig. 10). still, most adjacent landslide accumulations could be recognized and delineated precisely by the linear patterns of the small drainage channels that usually form along their boundary, and which are reflected on the planform curvature map and the stream power index map. previous studies on landslide identification and mapping (e.g., ardizzone et al., 2007; van den eeckhaut et al., 2007; petschko et al., 2016) determined that the visual interpretation of lidar imagery is characterized by a certain degree of subjectivity, and that it also implies certain simplifications within geomorphological deduction (guzzetti et al., 2012). however, the degree of subjectivity in this study is considered to be low, for the following reasons: (i) the topography of landslide phenomena is recognized on a considerable number of different lidar derivatives and their combinations according to established mapping criteria (fig. 3); (ii) landslide types (hungr et al., 2014) are distinguished according to the type of movement that is clearly reflected by the shape and size of delineated polygons (soeters & van westen, 1996), and they are also verified by field identification (fig. 4 and 6); (iii) landslides occur within a specific and isolated topographic environment characterized by relatively uniform morphological and geological conditions (e.g., biondić & vulić, 1970; blašković, 1999), that resulted in the limited number of landslide types formed in the same material; and (iv) the landslide inventory of the slani potok gully is produced by experts with adequate understanding both of the study area (đomlija, 2018) and the associated landslide types (e.g., arbanas, 2000, 2002), which significantly contributes to the quality of the results (van den eeckhaut et al., 2005). the described mapping procedure has achieved the high geographical accuracy of results in accordance to the 1 x 1 m spatial resolution of the lidar dtm, and thus the high quality of the landslide inventory. however, landslide mapping was an iterative and time­consuming process, to which the topographic location of landslides within an area with significant soil erosion processes that influence the overall surface topography area also contributed. the landslide inventory of the slani potok gully can be considered as an incomplete inventory (malamud et al., 2004) because the smallest and the largest landslides are missing in the frequency­size distribution (fig. 10), which is a common characteristic of most historical inventories (e.g., guzzetti et al., 2012). nevertheless, the landslide inventory of the slani potok gully provides useful information on the landslide types and realistic boundaries of individual phenomena, as well as their spatial arrangement and relative density within the gully, as well as their average size. these findings can certainly contribute to a more accurate forecast of the propagation and development of future landslide phenomena in the slani potok gully, i.e., the landslide types and their proxy dimensions and positions. although the state of activity is not determined in this study, most of the identified landslides are considered active (wp/wli, 1993), especially in the upper denuded part of the gully channel. certain landslide phenomena (e.g., fig. 4a­c and f) have been activated within the past few years, after airborne laser scanning was performed in march 2012. therefore, landslide activity, interrelated with soil erosion processes (đomlija, 2018), contributes to sedi­ ment production within the slani potok gully and also might lead to the widening of the gully channel in the future, which can potentially further endanger its surroundings. 6. conclusions two types of landslides according to the updated varnes classification of landslide types (hungr et al., 2014) were identified in the slani potok gully situated in the central part of the vinodol valley, based on the detailed visual interpretation of seven hr lidar 1 x 1 m topographic derivatives. these are debris slide, and debris slide­debris flow. a geomorphological historical landslide inventory map of the slani potok gully (area of 0.48 km2) was prepared, comprising a total of 181 landslide phenomena. landslides cover 69 % (0.33 km2) of the area of the slani potok gully. the size of the smallest landslide is 65 m2, and of the largest is 10,563 m2. the size of the most abundant debris slide is approximately 2,500 m2, and the size of the most abundant debris slide­debris flow is approximately 2,700 m2. landslides mainly exhibit a successive distribution. they generally initiate along the margins of the gully channel walls, and extend to the gully channel bottom. such a specific spatial arrangement of landslides identified in the slani potok gully confirms that the landslide types, geometry, style and distribution of activity are predominantly determined by the topographic location of the landslides, and that those landslides, at the same time, determine the shape and morphological evolution of the gully. the results of this study indicate that the visual interpretation of hr lidar derivatives is an effective method for identification and mapping of landslides in the slani potok gully, despite their specific spatial arrangement and relatively small dimensions, and the soil erosion processes influencing the landslide topography. however, in such areas of research, where there are significant differences in the visibility of landslide topography on lidar maps, the use of as many lidar maps as possible is recommended, to correctly recognize and map boundaries of individual landslide features. this method has also proven to be effective for the classification of landslide types according to the updated varnes classification (hungr et al., 2014), in combination with field investigations that are needed for the determination of landslide-forming material. the existence of such a large number of landslides identified in the slani potok gully suggests the need to re­examine certain g eologia c roatica jagodnik p. et al.: landslide types in the slani potok gully, croatia 27 considerations about the geomorphological processes in the study area. previous research (benac et al., 2005; jurak et al., 2005; aljinović et al., 2010) suggests that excessive erosion predominates in the development of the slani potok gully, with the landslides formed in the eroded soil mass as the associated phenomena. thereby, the landslides were never investigated in detail, given the available conventional research methods involving only field investigations, which did nor enable the identification of individual landslides and the production of an appropriate landslide inventory of the slani potok gully. only the recent and new technologies for landslide mapping, such as the lidar technology, have enabled the detailed topographic analysis and reco­ gnition of such a large number of individual landslides. conside­ ring the main findings of this study, it can be concluded that the initiation of a large number of landslides along the gully channel margins predominantly affects the morphologic development of the slani potok gully, and that soil erosion is the secondary process, which has a greater affect on the soil mass displaced by landslides than the flysch bedrock. erosion processes are nevertheless significant, as they are considered to be one of the main landslide preparatory causal factors in this area. finally, it is considered that the presented historical landslide inventory map of the slani potok gully can significantly contribu te to the sustainable land development in the study area, and that it can be efficiently used for future landslide susceptibility analysis. the information about landslide types and their additional characteristics can also contribute to geomorphological analyses in predicting the future development of the slani potok gully, as well as the general landscape evolution in the central part of the vinodol valley. acknowledgment the results presented herein have been obtained in the framework of the croatian­japanese bilateral project risk identification and land­use planning for disaster mitigation of landslides and floods in croatia, funded by the japan agency for science and technology (jst) and japan international cooperation agency (jica) through the science and technology research partnership for sustainable development (satreps) program. references aljinović, d., jurak, v., mileusnić, m., slovenec, dr. & presečki, f. (2010): the origin and composition of flysch deposits as an attribute to the excessive erosion of the slani potok valley (‘’salty creek’’), croatia.– geologia croatica, 63/3, 313–322. doi: 104154/gc.2010.25 amundsen, j., johnson, s., rouse, k. & wang, h. (2010): using lidar‐derived dems to delineate and characterize landslides in northern kentucky and hamilton county, ohio. retrieved from http: //www.trishock.com/academic/pdf/ lidar_landslides.pdf antonini, g., ardizzone f., cardinali, m., galli, m., guzzetti, f. & reichenbach, p. (2002): surface deposits and landslide inventory map of the area affected by the 1997 umbria–marche earthquakes.– bollettino della societa geologica italiana, 121/2, 843–853. arbanas, ž. (2000): geotehnički projekt županijske ceste žc 5064 križišće – tribalj – grižane – bribir – novi vinodolski, dionica barci (grižane) [geotechnical design of the county road cr 5064 križišće – tribalj – grižane – bribir – novi vinodolski, route barci (grižane) – in croatian].– institut građevinarstva hrvatske, pc rijeka. arbanas, ž. (2002): klizište ugrini na županijskoj cesti žc 5062 bribir – lič, idejni projekt sanacije [ugrini landslide on county road cr 5062 bribir – lič, preliminary design – in croatian].– institut građevinarstva hrvatske, pc rijeka. ardizzone, f., cardinali m., galli m., guzzetti, f. & reichenbach, p. (2007): identification and mapping of recent rainfall­induced landslides using elevation data collected by airborne lidar.– natural hazards and earth system sciences, 7, 637–650. doi: 10.5194/nhess­7­637­2007 bell, r., petschko, h., röhrs, m. & dix, a. (2012): assessment of landslide age, landslide persistence and human impact using airborne laser scanning digital terrain models.– geografiska annaler: series a, physical geography, 94, 135–156. doi: 10.1111/j.1468­0459.2012.00454.x bernat, s., đomlija, p. & mihalić arbanas, s. (2014): slope movements and erosion phenomena in the dubračina river basin: a geomorphological approach.– in: mihalić arbanas, s. & arbanas, ž. (eds.): proceedings of the 1st regional symposium on landslides in the adriatic­balkan region: landslide and flood hazard assessment. zagreb: croatian landslide group – faculty of mining, geology and petroleum engineering of the university of zagreb and faculty of civil engineering of the university of rijeka, 79–84. bernat gazibara, s., krkač, m. & mihalić arbanas, s. (2019): verification of historical landslide inventory maps for the podsljeme area in the city of zagreb using lidar­based landslide inventory.– the mining­geology­petroleum bulletin, 34/1, 45–58. doi: 10.17794/rgn.2019.1.5 benac, č., jurak, v., oštrić, m., holjević, d. & petrović, g. (2005): pojava prekomjerne erozije u području slanog potoka (vinodolska dolina) [an excessive erosion phenomenon in the slani potok (vinodol valley) – in croatian].– in: velić, i., vlahović, i. & biondić, r. (eds.): abstracts book of the 3rd croatian geological congress, croatian geological survey, zagreb, 173–174. biondić, b. & vulić, ž. (1970): klizište grižane 1968. inženjerskogeološki radovi [grižane landslide 1968 – engineering geological investigations – in croatian].– institut za geološka istraživanja, zagreb. blašković, i. (1999): tectonics of part of the vinodol valley within the model of the continental crust subduction.– geologia croatica, 52/2, 153–189. doi: 10.4154/gc.1993.13 cean, croatian agency for environment and nature (2008): corine land cover croatia, land use map 1:100,000. clague, j.j. & roberts, n.j. (2012): landslide hazard and risk.– in: clague, j.j. & stead, d. (eds.): landslides: types, mechanisms and modeling.– cambridge, university press, united kingdom, 1–9. doi: 10.1017/cbo9780511740367.002 crozier, m.j. (1986): landslides: causes, consequences and environment.– croom helm, england. crozier, m.j. (2010): landslide geomorphology: an argument for recognition, with examples from new zealand.– geomorphology, 120/1–2, 3–15. doi:10.1016/j. geomorph.2009.09.010 cruden, d.m. & varnes, d.j. (1996): landslide types and processes.– in: turner, a.k. & schuster, r.l. (eds.): landslides, investigation and mitigation. transportation research board, special report 247, washington d.c., usa, 36–75. domjan, e. (1965): izvještaj o terenskim sondažno istražnim radovima na lokaciji klizišta kraj grižana [technical report on field investigations of grižane landslide – in croatian].– rijekaprojekt, rijeka. đomlija, p., bernat, s., mihalić arbanas, s. & benac, č. (2014): landslide inventory in the area of dubračina river basin (croatia).– in: sassa, k., canuti, p. & yin, y. (eds.): landslide science for a safer geoenvironment, vol. 2. methods of landslide studies, springer international publishing, 837–842. doi: 10.1007/978­3­319­05050­8_129 đomlija, p. (2018): identification and classification of landslides and erosion phenome na using the visual interpretation of the vinodol valley digital elevation model.– dissertation. university of zagreb, faculty of mining, geology and petroleum engineering. đomlija, p., bernat gazibara, s., arbanas, ž. & mihalić arbanas, s. (2019a): identification and mapping of soil erosion processes using the visual interpretation of lidar imagery.– isprs international journal of geo­information, 8, 438. doi: 10.3390/ijgi8100438 đomlija, p., prša, m., jagodnik, v. & arbanas, ž. (2019b): preliminary testing of clay activity from landslide deposits in dubračina river basin, croatia.– in: uljarević, m., zekan, s., salković, s. & ibrahimović, dž. (eds.): proceedings of the 4th regional symposium on landslides in the adriatic – balkan region. sarajevo: geotechnical society of bosnia and herzegovina, 121–126. doi: 10.35123/resylab_2019_20 frevert, r.k. (1955): soil and water conservation engineering.– wiley, new york. galli, m., ardizzone, f., cardinali, m., guzzetti, f. & reichenbach, p. (2008): comparing landslide inventory maps.– geomorphology, 94, 268–289. doi: 10.1016/j.geomorph.2006.09.023 grošić, m. (2013): lokalna cesta lc 58075, lokalitet podbadanj. geotehnički izvještaj [local road lr 58075, podbadanj location. geotechnical report – in croatian].– geotech d.o.o., rijeka. guzzetti, f., malamud, b.d, turcotte, d.l. & reichenbach, p. (2002): power­law correlations of landslide areas in central italy.– earth and planetary science letters, 195, 169–183. doi: 10.1016/s0012­821x(01)00589­1 guzzetti, f. (2006): landslide hazard and risk assessment.– dissertation. mathematisch­naturwissenschaftlichen fakultät der rheinischen friedrich­wilhelms­universität, bonn, germany. guzzetti, f., mondini, a.c., cardinali, m., fiorucci, f., santangelo, m. & chang, k.t. (2012): landslide inventory maps: new tools for an old problem.– earth­science reviews, 112, 42–66. doi: 10.1016/j.earscirev.2012.02.001 g eo lo gi a c ro at ic a geologia croatica 73/128 haugerud, r.a., harding, d.j., johnson, s.y., harless, j.l., weaver, c.s. & sherrod, b.l. (2003): high­resolution lidar topography of the puget lowland, washington ­ a bonanza for earth science. gsa today, 13/6, 4–10. doi: 10.1130/1052­5173(2003)13<0004:hltotp>2.0.co;2 hungr, o., leroueil, s. & picarelli, l. (2014): the varnes classification of landslide types, an update.– landslides, 11, 167–194. doi: 10.1007/s10346­013­ 0436­y icl, international consortium on landslides (2018): instructions for world reports on landslides.– retrieved from https://www.iplhq.org igu, international geographical union, commission on applied geomorphology, subcommission on geomorphological mapping (1968). the unified key to the detailed geomorphological map of the world 1: 25,000 – 1: 50000.– in: klimaszewski, m. (ed.): part i. problems of the detailed geomorphological map; bashenina, n.v., gellert, j. & jolly, f. et al. (eds.): part ii. project of the unified key to the detailed geomorphological map of the world. krakow: folia geografica, series geographica­physica 2. jaboyedoff, m., oppikofer, t., abellan, a., derron, m., loye, a., metzger, r. & pedrazzini, a. (2012): use of lidar in landslide investigation: a review. natural hazards, 61, 5–28. doi: 10.1007/s11069­010­9634­2 jurak, v., slovenec, d. & mileusnić, m. (2005): pretjerana erozija fliša – slani potok [an excessive flysch erosion – slani potok – in croatian].– in: biondić, r., vlahović, i. & velić, i. (eds.): excursion guide book of 3rd croatian geological congress, croatian geological survey, zagreb, 51–55. kasai, m., ikeda, m., asahina, t. & fujisawa, k. (2009): lidar­derived dem evaluation of deep­seated landslides in a steep and rocky region of japan.– geomorphology, 113, 57–69. doi: 10.1016/j.geomorph.2009.06.004 keaton, j.r. & degraff, j.v. (1996): surface observations and geologic mapping.– in: turner, a.k. & schuster, r.l. (eds.): landslides, investigation and mitigation. transportation research board, special report 247, washington d.c., usa, 178–230. kostenko, n.p. (1975): quaternary deposits of highlands [in russian], moscow. košir, a., martín­pérez, a. & popit, t. (2013): zakaj je slano blato slano? [why is slano blato salty? – in slovenian].– in: rožić, b. (ed.): razprave, poročila = treatises, reports, 21st meeting of slovenian geologists, ljubljana, university of ljubljana, faculty of natural sciences and engineering, department of geology, 75–77. malamud, b.d., turcotte, d.l., guzzetti, f. & reichenbach, p. (2004): landslide inventories and their statistical properties.– earth surface processes and landforms, 29, 687–711. doi: 10.1002/esp.1064 mccalpin, j. (1984): preliminary age classification of landslides for inventory mapping.– proceedings of the 21st annual engineering geology and soils engineering symposium university press, moscow, idaho, 99–111. mihalić, s. & arbanas, ž. (2013): the croatian–japanese joint research project on landslides: activities and public benefits.– in: sassa, k., rouhban, b., briceño, s., mcsaveney, m. & he, b. (eds.): landslides: global risk preparedness, heidelberg: springer, 333–349. mihalić arbanas, s. & arbanas, ž. (2014): landslides: a guide to researching landslide phenomena and processes.– in: gaurina međimurec, n. (ed.): handbook of research on advancements in environmental engineering. engineering science reference, hershey pa, 474–508. doi: 10.1007/978­3­642­22087­6_24 mihalić arbanas, s., krkač, m. & bernat, s. (2016): application of advanced technologies in landslide research in the area of the city of zagreb (croatia, europe).– geologia croatica, 69/2, 231–243. doi: 10.4154/gc.2016.18 mileusnić, m., slovenec, d. & jurak, v. (2004): thenardite­efflorescence indicating cause of the excessive flysch erosion, slani potok, croatia.– acta minera­ logica­petrographica, abstract series, 75–75. mitas, l. & mitasova, h. (1999): spatial interpolation.– in: longley, p., goodchild, m.f., maguire, d.j. & rhind, d.w. (eds.): geographical information system: principles, techniques, management and applications (2nd edition). wiley, chichester, 481–492. moore, i.d., grayson, r.b. & ladson, a.r. (1991): digital terrain modelling: a review of hydrological, geomorphological, and biological applications.– hydrological processes 5, 3–30. doi: 10.1002/hyp.3360050103 pajalić, s., đomlija, p., jagodnik, v. & arbanas, ž. (2017): diversity of materials in landslide bodies in the vinodol valley, croatia.– in: mikoš, m., vilimek, v., yin, y. & sassa, k. (eds.): advancing culture of living with landslides, volume 5, springer, 507–516. doi: 10.1007/978­3­319­53483­1_60 petschko, h., bell, r. & glade, t. (2016): effectiveness of visually analyzing lidar dtm derivatives for earth and debris slide inventory mapping for statistical susceptibility modeling.– landslides, 13/5, 857–872. doi: 10.1007/s10346­015­ 0622­1 popit, t. & verbovšek, t. (2013): analysis of surface roughness in the sveta magdalena paleo­landslide in the rebrnice area.– rmz – materials and geoenvironment, 60, 197–204. popit, t., supej, b., kokalj, ž. & verbovšek, t. (2016): comparison of methods for geomorphometric analysis of surface roughness in the vipava valley.– geodetski vestnik, 60/2, 227–240. doi: 10.15292/geodetski­vestnik.2016.02.227­240 popit, t. (2017): origin of planation surfaces in the hinterland of šumljak sedimentary bodies in rebrnice (upper vipava valley, sw slovenia).– geologija, 60/2, 297–307. doi: 10.5474/geologija.2017.021 razak, k.a., straatsma, m.w., van westen, c.j., malet, j.p. & de jong, s.m. (2011): airborne laser scanning of forested landslides characterization: terrain model quality and visualization.– geomorphology, 126, 186–200. doi: 10.1016/j.geomorph.2010.11.003 rib, h.t. & liang, t. (1978): recognition and identification.– in: turner, a.k. & schuster, r.l. (eds.): landslides, investigation and mitigation. transportation research board, special report 247, washington d.c., usa, 34–80. scaioni, m., longoni, l., melillo, v. & papini, m. (2014): remote sensing for landslide investigations: an overview of recent achievements and perspectives.– remote sensing, 6/10, 9600–9652. doi: 10.3390/rs60x000x schuster, r.l. (1996): socioeconomic significance of landslides.– in: turner, a.k. & schuster, r.l. (eds.): landslides, investigation and mitigation. transportation research board, special report 247, washington d.c., usa, 12–35. schuster, r.l. & kockelman, w.j. (1996): principles of landslide hazard reduction.– in: turner, a.k. & schuster, r.l. (eds.): landslides, investigation and mitigation. soeters, r. & van westen, c.j. (1996): slope instability recognition, analysis and zonation.– in: turner, a.k. & schuster, r.l. (eds.): landslides, investigation and mitigation. transportation research board, special report 247, was­ hington d.c., usa, 129–177. strahler, a.n. (1952): hypsometric (area – altitude) analysis of erosional topography.– bulletin of the geological society of america, 63/11, 1117–1142. doi: 10.1130/0016­7606(1952)63%5b1117:haaoet%5d2.0.co;2 strahler, a.n. (1957): a quantitative analysis of watershed geomorphology.– transactions of the american geophysical union, 38/6, 913–920. doi: 10.1029/ tr038i006p00913 šestanović, s. (2001): osnove geologije i petrografije [basics of geology and petrography – in croatian].– university of split, faculty of civil engineering, split. štajduhar, m. (1976): odron na cesti grižane – kamenjak (kraj crikvenice) [fall on grižane – kamenjak road (near crikvenica settlement) – in croatian].– geomechanical report, geotehnika, institut "geoexpert", zagreb. šušnjar, m., bukovac, j., nikler, l., crnolatac, i., milan, a., šikić, d., grimani, i., vulić, ž. & blašković, i. (1970): osnovna geološka karta sfrj 1:100,000, list crikvenica, l33­102 [basic geological map of sfry 1:100,000, crikvenica sheet l33-102 – in croatian].– institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd. tomić, a., hrvojić, e., lušičić, i. & velnić, m. (1977): izvještaj o klizištu slani potok i male dubračine – kod grižana [technical report on the slani potok and mala dubračina landslide – in croatian].– opće vodoprivredno poduzeće, rijeka. toševski, a. (2013): inventar klizišta u slivu rijeke dubračine [landslide inventory in dubračina river basin – in croatian].– rudarsko­geološko­naftni zbornik, 27/1, 1–16. van den eeckhaut, m., poesen, j., verstraeten, g., vanacker, v., moeyersons, j., nyssen, j. & van beek, l.p.h. (2005): the effectiveness of hillshade maps and expert knowledge in mapping old deep – seated landslides.– geomorphology, 67, 351–363. doi: 10.1016/j.geomorph.2004.11.001 van den eeckhaut, m., poesen, j., verstraeten, g., vanacker, v., nyssen, j., moeyersons, j., van beek, l.p.h. & vandekerckhove, l. (2007): use of lidar­derived images for mapping old landslides under forest.– earth surface processes and landforms, 32, 754–769. doi: 10.1002/esp.1417 varnes, d.j. (1978): slope movements, type and processes.– in: schuster, r.l. & krizek r.j. (eds.): landslide analysis and control, transportation research board, special report 176. national academy of sciences, washington, 11–33. varnes, d.j. & iaeg commision on landslides and other mass­ movements (1984): landslide hazard zonation: a review of principles and practice.– the unesco press, paris. wehr, a. & lohr, u. (1999): airborne laser scanning–an introduction and overview.– isprs journal of photogrammetry and remote sensing, 54/2–3, 68–82. doi: 10.1016/s0924­2716(99)00011­8 wieczorek, g.f. (1984): preparing a detailed landslide­inventory map for hazard evaluation and reduction.– bulletin of the association of engineering geologists, 21/3, 337–342. doi: 10.2113/gseegeosci.xxi.3.337 wp/wli, international geotechnical society’s unesco working party on world landslide inventory (1993): a suggested method for describing the activity of a landslide.– bull. intern. assoc. eng. geol., 47, 53–57. zaninović, k., gajić­čapka, m., perčec tadić, m., vučetić, m., milković, j., bajić, a., cindrić, k., cvitan, l., katušin, z., kaučić, d., likso, t., lončar, e., lončar, ž., mihajlović, d., pandžić, k., patarčić, m. & vučetić, v. (2008): klimatski atlas hrvatske: 1961­1990, 1971­2000 [climate atlas of croatia: 1961-1990, 1971-2000 – in croatian].– croatian meteorological and hydrological service, zagreb. www.geologia-croatica.hr the alpine wilson cycle and nw tethyan metallogeny editorial dear readers, this issue of geologia croatica (the alpine wilson cycle and nw tethyan metallogeny) is devoted to ivan jurković, a professor emeritus of economic geology (ore petrology) and ore microscopy at the faculty of mining, geology and petroleum engineering and the former rector of the university of zagreb, who passed away on the 30th december, 2014. more about his life and an extensive bibliography can be found in in memoriam at the end of this issue. his fruitful and productive life was characterized by full devotion to science and care for education of generations of geologists. geological investigations of prof. jurković cover, beside all republics of the former state, a vast global territory in africa, asia and south america. in educational, social, and political domain he served many highly ranked duties. ivan jurković is a founder of modern studies in the field of ore genesis and metallogeny in croatia. his scientific credo, as a ground of research credibility urged to join different geological disciplines into a complex subject of science of ore deposits. he recognized, in his early research days, importance of symbiosis of regional geology and ore genesis, termed metallogeny. in the century of revolutionary affirmation of global tecto­ nics as deus ex machina of orogenesis, ivan jurković without hesitation accepted its principles and bravely incorporated wilson cycle into the studies of ore deposits in dinarides. as his successors, we try to follow a backbone of his fruitful ideas and research philosophy. in the coming years new generation of researcher keeps in line with the track routed by his principles. this issue is a selection of papers on genesis of ore deposits in the nw tethyan domain from alps, dinarides, carpathians and hellenides. submitted papers bring results of new research, but also valuable reviews, collection of long-time experience about the theme close to life-time interest of professor ivan jurković in behalf of memories to this extraordinary scientist. the choice of subjects is tightly leaned to synthesis of regional geology, petrology, and geochemistry, serving as a ground for modelling genesis of ore deposits. the following papers give an overwiev in discourse with the phases of wilson cycle in the evolution of the nw tethyan metallogeny, from the incipient rifting to the collision of the two immense continental blocks gondwana and eurasia. the rifting phase assumes a half of the total duration of the wilson cycle. it started in the middle permian and continued till the end of the triassic, gradually developing into the pelagic environment underlain by an oceanic crust. the rifting itself is divided into two phases with distinguished characteristics, the early intra-continental rifting and the advanced rifting stage. however, this important distinction is usually not enough recognized or appreciated. their diversification brings plethora of phenomena in tectonism, magmatism, sedimentary facies and ore deposit formation. the ore deposits related to early intra-continental rifting were exemplified by paper palinkaš et al.: the ljubija geothermal field, a herald of the pangea break-up (nw bosnia and herzegovina). a fascinating similarity between the siderite and magnesite deposits in the alps and those in dinarides, are their features which provoke a similar genetic model: high heat flow in the rift­environment which induced hydrothermal convection systems and mobilized the residual evaporitic brines. lithospheric extension and long-lasting thermal activity related to igneous and metamorphic activities are documented in the basement rocks of the adriatic plate, as stated in the paper presented by prochaska: genetic concepts on the formation of the austrian magnesite and siderite mineralizations in the eastern alps of austria. advanced rifting setting in middle triassic times is characterised by submarine volcanism, with immense pillow lava facies, and related hydrothermal processes. comparative studies on hydrothermal alteration of submarine peperitic basalt are described in details by kiss et al.: hydrothermal processes related to triassic and jurassic submarine basaltic complexes in northeastern hungary and in the dinarides and hellenides. basaltic volcanism is accompanied by formation of sedimentary-exhalative (sedex) deposits in the developing rifting basin adjacent to moesian carbonate platform. the carbonate platform itself hosts stratiform-stratabound base metal deposits with characteristics of mississippi valley type (mvt) deposits, or bleiberg­mežica types in the alps presented by marinova & damyanov: the triassic carbonate-hosted stratiform-stratabound base-metal deposits in the western balkan, nw bulgaria plate tectonics aspects. advanced rifting stage in middle triassic time proceeded by formation of a deep marine basin and divergent drifting of the passive continental margins already flanked by the newly formed dinaridic and moesian carbonate platforms. this is the scenario for genesis of the two contemporaneous types of deposits, sedex in the rift and mvt within the carbonate platforms facing each other on the opposite sides. recognition of this simple pairing mechanism by metallogenic patterns speaks in favour of the one ocean model in the early age of the tethyan history as imparted in the text by palinkaš et al.: diverging drifting of adriatic-dinaridic and moesian carbonate platforms during rifting phase witnessed by triassic mvt pb-zn and sedex deposits; metallogenic approach. intraoceanic subduction ocean-ocean setting in the neotethys in upper jurassic time is a turnover of extensional into compressional regime and beginning of the ocean closure. at the same time obduction of the overriding oceanic plate marks doi: 10.4154/gc.2016.01 2 vol. 69/1 the formation of the mélange, transfer of the obduction pressure onto the carbonate platform and progress of its tectonic bulging from the platform margin to the hinterland. it generated exposure of the drylands from the middle cretaceous to the paleogene as the most productive period of bauxite formation and the time of its influence on global climates and greenhouse effects. the bauxite formation as an inexhaustible repository of information on global climates is expressed in the paper mindszenty: bauxites: feedbacks of system earth at greenhouse times. one of the possible and probable candidates for subduction ocean-continent setting in the nw tethys is subsidence of the vardar oceanic crust beneath the serbo-macedonian continental mass. one of the convincing evidence is paroxysm of calc-alkaline magmatism typical products of arc-volcanism during the lower cretaceous in the timok area. it nested numerous morphogenetic types of ore deposits, with rich mineral and metal paragenesis. a review paper of jelenković et al.: the mineral resources of the bor metallogenic zone, a review, summarizes major genetic ore morphotypes in this unique metallogenic zone, a natural laboratory for interplay of magmatic heat and fluid rock interaction. collision and post-collision continent-continent setting is presented by four papers. igneous cenozoic rocks of the serbian part of the balkan peninsula are emplaced along a mega-suture that is left behind after the closure of neotethys ocean. from the metallogenic point of view the lower cretaceous subduction related magmatism, induced by subsidence of vardar oceanic crust beneath the serbo-macedonian continental block, was the most productive in the nw tethys history. the following scenarios mark a long retreat of the subduction slab to the west. it was going on by melting of a heterogeneous mantle during compressional regime, and succeeding decompression which increased contribution of crustal melts and enhanced its alkaline character. engagement of the crust caused enrichment of crustal metals, what resulted in creation of impressive metallogenic belt of dinarides presented by cvetković et al.: the rudnik mts. volcano-intrusive complex (central serbia): an example of how magmatism controls metallogeny. the bučim ore deposit belongs to the lece­chalkidiki meta­ llogenic zone as a part of the serbo-macedonian metallogenic province. it was developed at the contact of the ensialic serbomacedonian block and tectonically unstable vardar zone. the ore deposits are related to post-collisional intermediary calc-alkaline magmatism of neogene age. the metallogeny of the lece-chalkidiki zone is characterized by crustal elements pbzn­sb. porphyry copper deposits in the bučim ore field of the lece-chalkidiki zone represent an individual metallogenic unit with a clear metal zoning. dominance of copper among the metals is inheritance from ophiolites underlying the host crystalline rocks of serbo-macedonian massif. the detailed description of the bučim ore field is given by serafimovski et al.: porphyry cu mineralizations related with the small tertiary volcanic intrusions in the bučim ore deposit, eastern macedonia. the trepča pb­zn­ag skarn deposit, kosovo, is a part of the serbo-macedonian metallogenic province, at the border with the lece­chalkidiki metallogenic zone. trepča is a typical pro­ duct of post-collisional magmatic activation generating potassic to ultrapotassic magma, with strongly variable petrography. the magmatism and volcanism in the area was controlled by instability of the complex dinaride-hellenide orogen. the region of trepča deposit in the oligocene time was a site of frequent volcanic vent eruptions and maar-type phreatomagmatic explosion, what resulted in extensive hydraulic bracciations, important feature in the genetic evolution of the mineralization. phreatomagmatic explosions and formation of the breccia turned the system from lithostatic to hydrostatic regime and triggered retrograde stage increasing water activity and oxygen fugacity in the system described in strmić palinkaš et al.: origin and k-ar age of the phreatomagmatic breccia at the trepča pb-zn-ag skarn deposit, kosovo: implications for ore-forming processes. the most remarkable magmatic activity in paleogene-neogene times is in the periadriatic-sava-vardar zone, which follows the periadriatic lineament in the alps, and continuous into the dinarides and hellenides and marks closure of the neotethyan ocean and its slivers as central vardar ophiolite, west vardar ophiolite and dinaride ophiolite belts. the priabonian-neogenic magmatic activity in continuation is a generously productive metallogenic phase. it took place after the collisional processes in the balkanide-dinarides during the middle eocene and accommodates serbo-macedonian metallogenic province. the extension of the neogene metallogeny crosses the border between the serbo-macedonian and southern rhodopian formations in the thrace as the rhodope metallogenic province. the review paper of melfos & voudouris: fluid evolution in tertiary magmatic-hydrothermal ore systems at the rhodope metallogenic province, ne greece, focuses on the nature, composition and origin of magmatic­hydrothermal ore forming fluids involved in the formation of representative tertiary ore deposits at the rhodope metallogenic province in ne greece. this issue dedicated to late professor emeritus ivan jurković is a tribute to his significant contribution and presentation of nowadays development of idea he initiated. ladislav a. palinkaš, issue editor vladimir bermanec, issue editor lidija galović, editor-in-chief 2016 | 69/3 | 281–293 | 10 figs. | 5 tabs. | www.geologia-croatica journal of the croatian geological survey and the croatian geological society 1. introduction volcanic rock bodies, which reserve economically important amounts of hydrocarbon, are rather uncommon worldwide (e.g. farooqui et al., 2009). the üllés-ruzsa-bordány area in sw hun gary is one of these; the reservoir consists of monotonous basalt and its pyroclastic varieties (kecel basalt formation – kbf), approximately 200 m thickness. early studies support detailed petrographic results on kbf focusing exclusively on the highly altered host rock itself (cserepesné, 1978; pap, 1983; balázs & nusszer, 1987). today, important aspects concerning the reservoir characteristics are also studied (szabó et al., 2009a, b, 2012). due to the dense fracture network and the significant fracture porosity, some depth intervals of the igneous body show good reservoir characteristics. these fractures are partially or entirely cemented by various minerals making examination of their fluid inclusions and so principles of ancient fluid migration events possible. four distinct vein types can be distinguished based on textural and mineralogical features. named after their volumetrically most abundant cement phases, these are the potassium-feldspar (kfp-), calcite (cal-), laumontite (lmt-) and the analcime (anl-) types, respectively. a summary of the characteristics of all these vein types was published in szabó et al. (2009a), while the detailed description and circumstances of the palaeofluid evolution in a fractured basalt hosted reservoir in the üllés-ruzsa-bordány area, southern sector of the pannonian basin barbara szabó1,2, félix schubert2, tivadar m. tóth2 and gábor steinbach3,4 1 exploration and production, mol plc., budapest, hungary 2 university of szeged, department of mineralogy, geochemistry and petrology, h-6701 szeged, p. o. box 651, hungary; (barbokster@gmail.com) 3 biological research centre, szeged, hungary 4 cas, centrum algatech, institute of microbiology, třeboň, czech republic doi: 10.4154/gc.2016.25 abstract extensive miocene volcanic activity produced basaltic and pyroclastic successions, which were penetrated by many wells in the area of üllés-ruzsa-bordány, in the western and central part of the great hungarian plain. the kecel basalt comprises primary porosity from a high proportion of vesicles and significant secondary fracture porosity, as well. due to the significant fracture porosity, some depth intervals show good reservoir characteristics, although the fractures crosscutting the rock body are partly or entirely cemented by various minerals. based on the textural and mineralogical features, four distinct vein types can be distinguished, named after their volumetrically most abundant cement phases, i.e. potassium-feldspar (kfp-), calcite (cal-), laumontite (lmt-) and analcime (anl-) types. this study focuses on probably the youngest of these vein types, the anl-type. based on the study of veins and mineral sequences, the direction of temperature changes cannot be given unequivocally for every stage of cementation, but crystallization of the anl-type veins might have occurred at lower temperatures than the formation of the lmt-type veins. fluid inclusion studies suggest that hydrocarbon migration and accumulation took place after cementation of the first three vein types (kfp-, caland lmt-types). in the newly opened fracture system, two types of hydrocarbon (hc1 and hc2)-bearing fluid inclusion assemblages were captured during precipitation of analcime and later zeolites. this refers to two stages of hydrocarbon migration in the fracture system. observations of the fluorescence colours and low temperature behaviours of the hydrocarbon-bearing inclusions, the earlier hc1 petroleum-inclusions captured heavier (presumably less mature oils), while the later ones (hc2) lighter (presumably more mature) oils. the hc2 petroleum seems to be very similar to the crude oil sampled in a well in the area based on their fluorescence parameters. evolution of the first three types were discussed by szabó et al. (2009b). nevertheless, from a petroleum geology point of view, the most important vein generation is the youngest one, since hydrocarbon inclusions were identified exclusively in its vein filling mineral phases (szabó et al., 2009a). it was previously proven (szabó et al., 2009a) that rocks of the kbf are characterized by two types of porosity comprising an extended fracture system and partially-filled vesicles.the occurrence of similar petroleum inclusions both in the cemented anl-veins and in the adjacent wall-rock vesicles suggests that filling of the reservoir took place not only along localized fractures but also along altered basaltic zones around them. the evolution of the youngest vein generation and its role in the hydrocarbon system in question is the focus of the present paper. the key questions concern the subsidence history of the area through estimating temperature and pres sure change during the formation of the reservoir, as well as the stages and the timing of petroleum migration. utilising geochemical data, szabó et al. (2012) evidenced a genetic relationship between the potential source rock (marl) and the hydrocarbons produced. from this aspect the area in question is a hy dro carbon system based on the definition of magoon (2004). the study of the vein-filling minerals and their fluid inclusion assemblages could provide valuable information about the post-volcanic evolution of the area, the circumstances of hydroarticle history: manuscript received may 19, 2015 revised manuscript accepted august 22, 2016 available online october 07, 2016 keywords: fractured basalt reservoir, pannonian basin, zeolite minerals, hydrocarbon-bearing fluid inclusion, fluorescence g eo lo gi a c ro at ic a geologia croatica 69/3282 carbon migration and the accumulation processes in a hydrocarbon system (e.g. karlsen et al., 1993; george et al., 1997; bourdet et al., 2010). in addition, the evolution of reservoir charging can further be specified by the methods of pironon et al. (1998) or aplin et al. (1999), who used the systematic change in homogenization temperature (th) and vapour volume fraction (φvap)values of petroleum inclusions in order to estimate the pressure of hydrocarbon migration. hereafter the vapour volume fraction is defined as the proportion of vapour volume and the amount of vapour and liquid volume (φvap=vvap/(vvap+vliq)). considering different thermometric data of all subsequent vein types, the post-volcanic temperature evolution and the subsidence history of the volcanic rocks could be modelled in the study area. data gained from fluid inclusion analyses could provide further contributions to our present knowledge regarding the stages and timing of petroleum migration. 2. geological setting several wells were drilled in the late miocene basaltic rocks of the kbf in the central and sw part of the great hungarian plain, in the area of szank, kiskunhalas, sándorfalva, pusztamérges, üllés, ruzsa and bordány (fig. 1) (cserepesné, 1978; pap, 1983; balázs & nusszer, 1987). the formation consists of pyroclastic and lava rocks interbedded with up to several hundred meter thick layers of the endrőd marl formation (emf). the endrőd marl is regarded as one of the most important source rocks in the area, although in many areas its thermal maturity is highly variable and the results of the oil-source correlations are not unequivocal (e.g. badics et al., 2011; badics & vető, 2012 and references therein). the lithofacies of the endrőd marl varies from calcareous to argillaceous marls, depending on palaeo water depth and other depositional conditions in the lake pannon (magyar et al., 1999). the tótkomlós calcareous marl member of the emf includes fossils (e.g. congeria cžjžeki m. hörn., congeria sp., limnocardium abichi r. hoern. var., l. cfr. abichi r. hoern., l. desertum stol., l. cf. desertum stol., l. triangul costatum mal., limnocarcium sp., amplocypris sp., candona (pontoniella) acuminata zalányi, c. (bacunella) sp., c. (camptocypria) sp., etc.) (balázs & nusszer, 1987). bas ed on biostratigraphic evidence the age of the calcareous marl underlying the pyroclastic rocks in the üllés-22 well is between 8.1–10.8 ma years (magyar et al., 2004). these results are in agreement with the whole rock k/ar radiometric ages of the volcanic rocks, determined as 8.13 ± 0.71 ma from kecel-1, as 9.61 ± 0.38 ma from kiskunhalas-ny-3 and as 10.4 ± 1.8 ma from the ruzsa-4 wells (cserepesné, 1978; pap, 1983; balázs & nusszer, 1987). the kbf has been explored in almost 30 wells in the areas of üllés, ruzsa and bordány (fig. 1). the volcanic rocks were penetrated between 2200 and 2900 m with a maximum thickness of 185 m. these basaltic rocks show intense chloritization and carbonatization as the result of metasomatism following the subaqueous volcanism (szabó et al., 2009b). fractures are often cemented by minerals (prehnite, chlorite, quartz, calcite), in particular by different zeolites (laumontite, thomsonite, analcime, mesolite, heulandite, stilbite). four distinct vein types can be disfigure 1. a) occurrence of the kecel basalt formation within the central pannonian basin of hungary. b) location of settlements in the vicinity of which rocks of the kecel basalt formation were reported from drillcores. c) a detailed sub-surface topographic and geological map of the study area. contours show depth (m) to pre-cenozoic basement. white dots mark wells (labelled üllés-) from which hydrocarbon-bearing analcime grains were investigated in this study (modified after haas et al., 2010). 1. middle triassic shallow marine siliciclastic and carbonate rocks. 2. lower-triassic siliciclastic rocks of fluvial and delta facies. 3. jurassic and cretaceous rocks. 4. pre-mesozoic basement. g eologia c roatica szabó et al.: palaeofluid evolution in a fractured basalt hosted reservoir in the üllés-ruzsa-bordány area, southern sector of the pannonian basin 283 table 1. the basic parameters of the occurring vein types.   kfp-type cal-type lmt-type anl-type host rock lapillis basalt basalt and pyroclast basalt and pyroclast occurrence ruzsa-21, üllés-61 bordány-2, üllés-77 ruzsa and üllés area (except for: üllés-61) üllés-61, üllés-65/a (in cuttings) vein microstructure syntaxial antitaxial syntaxial (ataxial) syntaxial cement minerals k-feldspar quartz albite laumontite calcite weathered volcanic material calcite heulandite prehnite chlorite laumontite thomsonite calcite analcime mesolite heulandite stilbite tinguished based on their mineral compositions and the textural relationships of the mineral sequences in the veins (table 1; fig.2). the veins of the earliest k-feldspar (kfp)-type could only be observed in lapillis and contain potassium feldspar, quartz, albite, laumontite and calcite (table 1). the basalt hosted calcite (cal)type veins are filled by altered volcanic material in the central part, and calcite and heulandite along the vein walls (table 1). these types formed prior to significant diagenetic alteration of the pyroclastic material. the laumontite (lmt)-type veins formed later, during formation of the early fracture network and are composed of the prehnite-laumontite-thomsonite-laumontitechlorite-calcite mineral sequence. details on the fracture fillings of the first three of the four vein types were given in szabó et al. (2009b). fluid inclusion microthermometry was performed on twophase (l+v) fluid inclusions in fracture-filling minerals with a well-defined position in the mineral sequence (table 1). in kfptype veins, the two-phased (l+v) aqueous inclusions in the kfeldspar, quartz and calcite crystals contain methane in the vapour phase at room temperature. in lmt-type veins, the primary inclusions in the prehnite contain methane in the vapour phase at room temperature, but the rare single two-phase aqueous inclusions in calcite with no identifiable genetics do not contain any methane. for the fluid inclusion petrography and microthermometry of the first three vein types (kfp-, caland lmt-types) see szabó et al. (2009b). post-volcanic temperature changes during their cementation were reconstructed for the first three types of veins (kfp-, caland lmttypes), based on their study andthermo-baromet-thermo-barometric mo dels, (szabó et al., 2009b):the minerals of the kfp-type veins precipitated in fractured lapilli before the final consolidation of the volcanic sediment at around 140–155 °c. the calcite of cal-type veins crystallised in the fractures of basalt after it was par tial ly filled by altered volcanic material. the earliest cement pha ses in the lmt-type veins from prehnite to thomsonite clearly sug gest a cooling trend during fracture cementation from around 130–180 °c to 50–90 °c. however, in the next phase, lmt veins suggest an increasing temperature for their late evolution (150–225 °c) on the basis of the temperature stability of laumontite. 3. samples and methods for petrological and analytical studies, core samples and cuttings from the collection of the mol hungarian oil and gas plc. were used. the cores of the üllés-61 well and cuttings from the üllés65/a well were chosen for further investigation as being representative of the fracture cementation of the anl-type veins and also because they exhibit traces of hydrocarbon migration (fig. 1). the crude oil was sampled from the well head of üllés-61 (table 2). prior to macroscopic observations, the samples were carefully cleaned by water and in some cases in an ultrasonic bath. the macroscopic observations were carried out to explore the main characteristics of the fractures, the paragenesis and spatial relationships of the fracture-filling minerals. the petrographic investigation of the host rock and fracture cement was performed on cores, cuttings and thin sections using olympus szx7 binocular and olympus bx41 polarization microscopes. raman microspectroscopy, fluid inclusion petrography and microthermometry figure 2. paragenetic diagram of fracture-hosted minerals indicating the reigning fluid regime during their precipitation. based on cross-cutting relationships the age of anl-type veins relative to the lmt-type ones cannot be determined unequivocally, hence, we have marked both of the feasible scenarios on the diagram. table 2. the samples from the study area. well kecel basalt formation (md in m) depth of sample (md m) type of sample rock type fracture-filling minerals ü-61 2235-2405 2238-2250 core basalt, basalt agglomerate k-feldspar, chlorite, calcite, analcime, mesolite, heulandite, stilbite 2329-2340 crude oil – – ü-65/a 2198-2340 2264-2330 cuttings basalt, basalt agglomerate prehnite, chlorite, laumontite, analcime, heulandite g eo lo gi a c ro at ic a geologia croatica 69/3284 were performed on thick sections prepared from core samples (6 sections) and cuttings (3 sections) at the department of mineralogy, geochemistry and petrology, university of szeged. prior to the analytical procedures and microscopic observations, thin sections (30–50 μm) and double-polished thick sections (75–150 μm) were prepared from the cores and cuttings. if it was necessary, the samples were impregnated with epoxy resin under vacuum at 40 °c for at least 24 hours, and then cut into pieces by a buehler isomet low speed saw. the surfaces were ground and polished using sic and diamond sprays. during the sample preparation the methods of shepherd et al. (1985) were followed. raman spectra of fracture-filling minerals and fluid inclusions were recorded in part with a horiba jobinyvone spectrometer connected with an olympus bx40 microscope (budapest university of technology and economics), and with a labramtype spectrometer connected to an olympus u-d6re microscope (university of nantes) using 50x and 100x lwd objectives and in accordance with the methods of bruke(1994). the radiating laser source operated at 532 nm in the former and at 488 nm in the latter case. the acquisition time was chosen depending on the intensity of the signal, usually 10–30 seconds in the case of minerals and 60–100 seconds in the case of fluid inclusions, accumulated 3–5 times. fluid inclusion petrography was performed on fracture-filling minerals of rock samples with a well-defined position in the mineral sequence. the observations were made using an olympus bx41 polarization microscope in normal and in ultraviolet light following the methods of goldstein (2003). based on the petrographic evaluation of the thick sections, uv fluorescent micro-spectroscopic measurements were carried out to identify the different petroleum inclusion assemblages. for this purpose a parissh spectral imaging system (lightform inc., hillsborough, nj, usa) mounted on an olympus ix71 inverted research microscope was used to collect the fluorescence spectra. the light from a selected line of the microscope’s field of view is wavelength dispersed by the spectrometer and focused on a peltiercooled charge coupled device. the recorded image consists of intensity values with their spatial and wavelength coordinates. the spectral imaging system provides simultaneously several full spectra uniformly distributed along a conveniently selected spatial direction. in these investigations the observation line (projection of the entrance slit) was chosen to be through the entire inclusion. during the detection an olympus u-mnu2 filter cube (excitation filter – 360–370 nm, emission filter – 420, dichromatic mirror – 400 nm) was used. about 100 spectra were measured and data collected on each petroleum inclusion. to optimize the signal-to-noise ratios, the spectrum of the highest intensity from among the collected spectra of the single petroleum inclusions was chosen. the uv fluorescent parameters of the crude oil sample were also measured by this equipment. for this a drop of the oil was put on a glass slice and it was covered by a quartz coverslip. to facilitate comparison between different inclusion generations, each spectrum was transformed into coordinates that can be plotted in the cie-1931 chromaticity diagram. this transformation (e.g. wyszecki & stiles, 2000) involved multiplication of the spectrum independently by three colour-matching functions, which describe the non-linear perception of the human eye to red, green and blue hues. integration of the three product functions over the acquired spectral range (400 to 880 nm) yields three so-called tristimulus parameters. their sum is the perceived colour according to the cie-1931 convention. the fraction of each parameter with respect to the sum corresponds to x, y and z chromaticity coordinates. as the three fractions add up to unity, only x and y need to be plotted in the orthogonal cie-1931 chromaticity space to conveniently describe the fluorescence colour of each analyzed fluid inclusion. data reading was made by microsoft excel and golden software surfer 8 softwares. confocal laser scanning microscopy (clsm) was applied to estimate the vapour volume fraction (φvap) of hc2 petroleum inclusions. the confocal images were acquired on an olympus fluoview fv1000 laser scanning confocal microscope (fv1000-inverted) using a 405 nm excitation laser source (emission filter 461–561nm, dichroic mirror dm405/488) using an olympus long working distance 40x objective. the intense motion of bubbles within the petroleum inclusions due to the excitation laser beam prevents image acquisition at room temperature. hence, we attached a linkam thmsg600 heating-freezing stage upside down on the stage of the confocal microscope. using spacers of appropriate height between the microscope and heating-freezing stage, petroleum inclusions could be scanned without focus limitations within the chip. the confocal images were obtained at the homogenization temperatures of the individual inclusions. during thresholding of the acquired images and the volumetric 3d reconstruction the following procedure was performed. the data area of the optical sectioning was thresholded by half of the maximum intensity of the sample and the volume of the pixels above the limit was counted (using the lateral and vertical resolution of the image acquisition). the volume of the bubbles was calculated using their measured diameters. the diameter of the gas bubbles was determined from photomicrographs, which were taken in transmitted light, focused at the widest (equatorial) section of each bubble at a known temperature. during selection of the petroleum inclusions for clsm analysis, we attempted to select inclusions with undistorted, spherical bubbles at room temperature. the detailed principles and the original procedures for the acquisition of clsm images of petroleum inclusions are described in pironon et al. (1998). microthermometry was carried out using a linkam thmsg -600 heating-freezing stage mounted on an olympus bx-41 microscope using long working distance objectives 100x. the stage was calibrated using synthetic fluid inclusions trapped in quartz with an open sample container covered with a silver lid at –56.6, 0.0 and 374 °c. the accuracy of the measurements was ±0.1 °c below and ±1 °c above 0 °c. the homogenization temperature was usually determined only with the cycling method (goldstein, 2003). the salinities of the aqueous inclusions are reported in mass% of nacl equivalent following the calculated values of bodnar (1993). the salinities were calculated from the final ice melting temperatures (tm(ice). the concentrations of methane in the methane-bearing inclusions are not known, so the possible effects of the dissolved methane and the methane-hydrate-clathrate to the salinity could not be deduced. the salinities of the present study are therefore maximum values (schubert et al., 2007). microthermometry data evaluation was followed after bakker& brown (2003). the pressure-temperature (p-t) conditions of the observed equilibrium mineral assemblages can be calculated using the thermodynamic properties of the minerals (holland & powell, 1998) with windomino software (de capitani & brown, 1987; de capitani, 1994). windomino calculates the minimum gibbs energy assemblage for a given p-t area in the case of a chemically closed system. these results could be compared to and completed by the estimations of liou et al. (1991) for the p-t stability fields of different zeolites, and by temperature data from g eologia c roatica szabó et al.: palaeofluid evolution in a fractured basalt hosted reservoir in the üllés-ruzsa-bordány area, southern sector of the pannonian basin 285 fluid inclusion microthermometric measurements as well as borehole temperature measurements (jorgen sen, 2006). the minerals in the present study are abbreviated according to whitney & evens (2010). vein microtextures are review ed following the nomenclature of bons (2000) and oliver & bons (2001). in the case of fluid inclusion terminology, those of diamond (2003) and schubert et al. (2007) were followed. discussion of the results of fluid inclusion petrography, microthermometry, raman spectroscopy and uv-fluorescent micro-spec tro scopy used the same abbreviations for the notation of fluid inclusion types and assemblages. with regard to the composition of the fluid inclusions, aq was used for the aqueous and hc for the hydrocarbon-containing fluid inclusions. for genetic types p for the primary, s for the secondary and ps for the pseudo-secondary were used. the subsequent assemblages were numbered with arabic numbers increasing from oldest to youngest ones. for example the earliest primary fluid inclusion assemblage with aqueous composition was noted as aq_p1. the physical phases of the contents of the fluid inclusions were abbreviated as l for liquid, v for vapour and s for solid phases. a phase change from a liquid plus vapour phase to a single liquid phase could be abbreviated as l+v→l. 4. results 4.1. petrography the core samples of üllés-61 are cross-cut by a dense vein network. the angular grains of the host rock show a brecciated structure and debris of vitrophyric-rimmed lapilli occurs among these rock fragments (fig. 3/a). the dense fracture network in the rock is partly or completely filled by zeolites. most of the pore space is filled by transparent or white crystals of analcime. leucitohedron-shaped crystals in the partially-filled voids can also be observed. on the blocky analcime crystals white, translucent, rhombic or coffin-shaped prisms of heulandite crystals could be seen. tiny needles appear as solid inclusions within the main fracturefilling analcime and heulandite crystals, which were identified as mesolite by raman spectroscopy (fig. 3/b, 3/c). the mesolite crystals are sporadically displayed in the analcime while in the heulandite it occurs more massively as radial aggregates (fig. 3/d). milky-white stilbite also occurs infrequently on the heulandite crystals. the sequence of the fracture-filling zeolites in these analcime-type (anl-type) veins is as follows: early mes → anl → late mes → heu → stb (table 1). the growth direction of the crystals extends from the vein walls towards the centre of the figure 3. a) the dense vein network is cemented by analcime, mesolite, heulandite and stilbite in a core sample from the üllés-61 well.the veins in the basaltic rock are partly open in places. the diameter of the coin is 10 mm. b) and c) the mesolite fibres in analcime (2b) and heulandite (2c) were detected by raman spectroscopy. d) theanl-type vein shows a syntaxial vein structure, the analcime, mesolite and stilbite crystals point to the centre of the vein. the vein is partly open at the top of the stilbite crystals. e) the leucitohedron-shaped analcime crystals and coffin-shaped heulandite crystals from cuttings from the üllés-65/a well. the diameter of the crystals are about half a millimetre. g eo lo gi a c ro at ic a geologia croatica 69/3286 veins, so the vein structure could be considered as syntaxial, according to bons (2000) (table 1, fig. 3/d). petrographic and raman spectroscopy studies on samples from the üllés-65/a well revealed narrow (1–2 mm wide) veins filled with analcime. although not as vein-filling, but as small pieces in the cuttings, we identified euhedral crystals: coffinor rhombic-shaped heulandite crystals and leucitohedron-shaped analcime crystals (fig. 3/e). trace amounts of fibre-shaped laumontite crystals also appeared in the cuttings of the üllés-65/a well. 4.2. windomino modeling the pressure-temperature (p-t) conditions of the observed equilibrium mineral assemblages can be calculated by windomino software, but it is only possible in a closed chemical system. so the p-t stability fields of the na-zeolites (analcime) and ca-zeolites (heulandite-stilbite) could be modeled separately. there are no thermodynamic data available for mesolite, because it is a mixed na-ca zeolite, so it could not be put in any of the models. analcime is stable in a very wide range of temperature and pressure conditions compared to heulandite and stilbite. the stability field of heulandite extends between 180 and 190 °c and below 500 bar. stilbite is stable below 180–190 °c, but its stability is not really dependent on pressure as it is stable from 100 bar –3 kbar. the equilibrium pressure-temperature zones of windomino could be compared with the zeolite stability zones shown on the figure 1 in liou et al. (1991) (fig. 4). the diagram in liou et al. (1991) shows that heulandite is stable between 140 and 220 °c and over a wide pressure range, from 850 – 2750 bar, while stilbite is stable below 140 °c and below 850 bar. the calculated equilibrium temperature ranges of the minerals are in agreement with their given temperature ranges by liou et al. (1991) suggests a decreasing temperature trend during fracture cementation (fig. 4). for pressure an unequivocal trend could not be given. 4.3. fluid-inclusion petrography and microthermometry during the fluid inclusion petrographic studies the criteria of gold stein (2003) were followed to classify fluid inclusion assemblages. in the anl-type veins, analcime contains measureable aqueous inclusions and analcime and heulandite contain measureable hc-containing fluid inclusions (fig. 5/a). in the mesolite fibre-shaped crystals no fluid inclusions suitable for micro thermometry were discovered. early and late primary (p) aqueous (a�) fl uid inclusion as-(p) aqueous (a�) fl uid inclusion as-aqueous (a�) fluid inclusion assemblages could be distinguished (aq_p1 and aq_p2) in analcime, trapped along growth zones. these assemblages straddle pseudo-secondary (ps) aqueous fluid inclusions trapped along healed fractures in the crystals (aq_ps). the aqueous inclusions have irregular shapes with a maximum dimension of 12 μm (a�_ p1) and 66 μm (a�_p2), respectively (table 3). the estimated φvap values at room temperature are constant within the individual inclusion assemblages. based on the uv fluorescence colours, two different types of hydrocarbon (hc1 and hc2)-containing inclusion assemblages were trapped within the analcime crystals along subsequent growth zones as described by szabó et al. (2012). the very infrequent primary, two-phase hc1_p inclusions have a very light brown colour in normal transmitted light, and an intense yellow fluorescence colour under uv excitation. the small groups of figure 4. the calculated equilibrium p-t ranges for heulandite (dark grey area) and stilbite (light grey area) by windomino with the zeolite stability zones (marked by the lines) of liou et al. (1991). the stability zone of heulandite is partly similar in temperature but totally different in pressure in the windomino calculations and in the calculations of liou et al. (1991). the stability zone of stilbite is partly similar in temperature, but windomino calculated a wider temperature dimension for stability at lower pressures than liou et al. (1991). figure 5. a) a reflected light photograph of a cemented multiphase fracture in basalt as host rock. the analcime and heulandite crystals are darker in places where they contain petroleum inclusions (üllés-61 well). b) the primary aqueous (aq_p2) and hc2-containing (hc2_p1, hc2_p2, hc2_p5) inclusions in analcime and hc-containing inclusions in heulandite in an üllés-61 sample cut under ultraviolet excitation and normal light. the aq_p2 and hc2_p1 inclusion assemblages are captured in the same growth zone – before the other hc2 inclusion generations (hc2_p2-p5) – therefore they are co-genetic with each other. the heulandite contains many hc-bearing inclusions without any recognizable growth zone. g eologia c roatica szabó et al.: palaeofluid evolution in a fractured basalt hosted reservoir in the üllés-ruzsa-bordány area, southern sector of the pannonian basin 287 these hc1-containing inclusions were trapped prior to the hc2containing inclusions (early type). the late type, hc2-containing, primary two-phase hc2_p inclusions are colourless in normal transmitted light and show a visually intense green fluorescence colour (fig. 5/b). large quantities of these inclusions could be observed along several successive growth zones. at least five zones could be distinguished in samples of the üllés-61 well (hc2_p1-hc2_p5) (fig. 5/b). the hc1_p inclusions were trapped after the aq_p1 early aqueous inclusions, but prior to the aq_p2 late aqueous inclusions. the earliest hc2_p inclusions are trapped in the growth zone of aq_p2 inclusions parallel to the aqueous inclusions (fig. 5/b). in some cases three-phase, oil-bearing aqueous inclusions occur in the zone of aq_p2 and hc2_p, which proves that the earliest zone of the hc2 inclusions (hc2_p1) are co-genetic with the aq_p2 inclusions. after the joint zone of aq_p2 and hc2_p inclusions we found many zones of hc2_p inclusions (hc2_p2, hc2_p3...etc.). the shapes of hc2 inclusions are more rounded than the aqueous inclusions, and their maximum dimension is 20 μm in samples of the üllés-61 well and 78 μm in samples of the üllés-65/a well. the volume fractions of the vapour phase (φvap) in the hc2 inclusions are mostly uniform at room temperature. in addition, secondary hc2-containing (hc2_s) inclusions could be observed along healed fractures in analcime. both hc1 and hc2 petroleum inclusions were analyzed under uv excitation and their fluorescence responses were detected in the visible-near infrared range (400–880 nm). a minute quantity of the produced petroleum fluid was also analyzed using an identical instrumental setup. the transformed spectra were converted into the cie-1931 chromaticity coordinates. each datum point represents one representative spectrum of a petroleum inclusion. in the cie diagram the petroleum types (hc1, hc2, produced oil) are arranged in two separate groups (fig. 6). the fluorescence properties of the hc1 and hc2 petroleum inclusions are located on different segments of the maturity curve (fig. 6), namely, the hc2 fluid is blue-shifted relative to the hc1 petroleum. the fluorescence datum point of the produced oil overlaps the points of hc2 (fig. 6). results of microthermometric measurements are provided in table 3. inclusions of the primary aqueous inclusion assemblages undergo homogenization to liquid (laq+v→laq) at 124 to 145 °c (a�_p1 inclusions), 129 to 149 °c (in üllés-61) and 131 to 142 °c (in üllés-65a) (both a�_p2). the pseudo-secondary aqueous aq_ps inclusions homogenize into the liquid phase (laq+v→laq), and the homogenization temperatures are similar to the primary inclusions, between 124–132 °c. based on the tm(ice) value of –0.3 and –0.4 ºc, the salinity of the a�_p2 inclusions is ca. 0.53–0.71 mass% in nacl equivalent (bodnar, 1993). there are no tm(ice) values and salinity data for aq_p1 inclusions because the small inclusions were not measureable. the th of hc1_p inclusions were very hard to measure, since inclusions generally decrepitated before the homogenization. however, one successful measurement yielded a th of 121.5 ±1 °c. the hc2_p inclusions were trapped along (at least) five different growth zones in üllés–61, but their homogenization temperatures do not show any appreciable temperature variance (table 3). the figure 6. a) ultraviolet-fluorescence colours of 4 hc1and 11 hc2 petroleum inclusions as well as the produced oil sample, plotted in the cie-1931 chromaticity diagram. b) inset marked with grey box in fig. 5a. it is obvious that the fluorescent properties of hc1 and hc2 petroleum inclusions differ significantly, while the fluorescence of the produced oil is practically identical with the late hc2 petroleum. table 3. microthermometric results in the anl-type veins. sample, enclosing mineral fluid inclusion type fluid inclusion size range (μm) th (°c) number of measurements tmice (°c) salinity (m/m%) number of measurements ü-61, analcime aq_p1 2-12 124-145 44 – – – aq_ps 4-20 124-132 16 – – – aq_p2 6-28 129-149 39 (-0.3)-(-0.4) 0.53-0.71 11 ü-65/a, analcime aq_p2 3-66 131-142 45 (-0.3) 0.53 2               ü-61, analcime hc1_p 40 121.5 1 – – – hc2_p1 4-8 113-118 35 – – – hc2_p2 3-10 110-121 12 – – – hc2_p3 3-20 110-121 9 – – – hc2_p4 5-11 116-123 5 – – – hc2_p5 6-13 111-120 5 – – – hc2_s 5-10 113-125 4 – – – ü-65/a, analcime hc2_p 3-78 108-118 23 – – – ü-61, heulandite hc2_p 8-10 121-134 5 – – – g eo lo gi a c ro at ic a geologia croatica 69/3288 homogenization always occurs into the liquid phase, and the temperature ranges (th) are as follows for the subsequent zones of hc inclusions: hc2_p1: 108–136 ºc, hc2_p2: 110–125 ºc, hc2_p3: 110–126 ºc, hc2_p4: 114–123 ºc, hc2_p5: 111–120 ºc in üllés-61. the primary hc2 inclusions (co-genetic with the aqueous inclusions) homogenize between 108–118 ºc in üllés-65a. the th distributions of aq_p2 and hc2_p1 inclusions in analcime from ü-61 and ü-65/a wells are provided in fig. 7. the a�_p2 and hc2_p1 inclusions have more similar th in samples of the üllés-61 well than the a�_p2 and hc2 inclusions in samples from the üllés-65/a well (with a similar number of measurements). heulandite also contains two-phase aqueous and hc-containing inclusions, but the genetics of the inclusions could not be clarified in most cases because the mesolite fibres were grown together with heulandite lamellae. there are just a few successful microthermometric measurements in heulandite, because the fluid inclusions decrepitated very easily in the crystals, which have a perfect cleavage parallel to the plane of symmetry. the presumably primary, hc-containing inclusions are rounded with a maximum dimension of 10 μm. they have no colour in normal transmitted light, and have intense blue fluorescence under uv excitation. based on these characteristics we suggest calling them hc2_p inclusions. these inclusion assemblages undergo homogenization to a liquid phase from 121 to 133 °c measured in the üllés-61 samples. the type and the density of the trapped oil can be estimated from microscopic observations at low temperatures (grimmer et al., 2003). observing the inclusions, both the hc1and the hc2-containing inclusions are in the two-phase domain at room temperature, and they homogenize into the liquid phase. cooling the samples down to –120 ºc none of them transformed into three phases (l+v→l1+l2+v) and the homogenization temperatures were not around +52 ºc, which excludes the trapping of condensate fluid in the samples. below 20 ºc, hc2-containing inclusions have a solid phase (presumably wax) in the liquid phase, and while heating the cooled sample, the slight motion of these particles could be observed with changing shape of the vapour bubble. hc1-containing inclusions do not show any of these reactions at low temperatures. according to grimmer et al. (2003), hc1containing inclusions show the behavior of inclusions containing black oil, and hc2-containing inclusions are commensurate with those containing light oil (fig. 8). 4.4. the raman micro-spectrometry of fluid inclusions in the anl-type veins, the composition of the primary and secondary aqueous inclusions trapped in analcime were determined by raman spectroscopy. qualitatively, these inclusions contain methane in the vapour phase at room temperature. the soundproof measurements – necessary for quantitative composition determinations – were disturbed by the presence of water captured in the structure of the analcime, due to the overlap of raman peaks of inclusion water and those of structural water (fig. 9). gas-hydrate (methane clathrate) formation and melting could not be observed and measured by raman micro-spectroscopy, so the accurate salinity of the aqueous inclusions and therefore the composition of the inclusions could not be given exactly. figure 7. homogenization temperature distributions of aq_p2 and hc2_p1 inclusions in vein-filling analcime from the üllés-61 and in üllés-65/a samples are presented. figure 8. hc2-containing inclusions in analcime have solid-phase particles in the liquid phase at low temperatures after a cooling procedure, while hc1-containing inclusions remain in the two-phase domain (l+v) after the cooling and reheating to 10 ºc (üllés-61 well). figure 9. the raman spectrum of an aq_p2 inclusion captured targeting the vapour phase from a vein-filling analcime sample at room temperature (üllés-65a) shows the peak of methane in the vapour phase (2916 cm–1) and the sign of liquid water with the peak of the crystal water of analcime (3557 cm–1). g eologia c roatica szabó et al.: palaeofluid evolution in a fractured basalt hosted reservoir in the üllés-ruzsa-bordány area, southern sector of the pannonian basin 289 4.5. uv fluorescent micro-spectrometry in case of the hc-containing inclusions and the crude oil, two parameters were calculated. the λmax (the wavelength of the excitation with the maximum intensity) and the � value (�=r/g quotient, which is the ratio of the intensities belonging to emission wavelengths at 650 nm and 500 nm, respectively) according to stasiuk & snowdon (1997). the representative values of λmax and � quotient are listed in table 4. in hc1-containing inclusions the micro-fluorescent parameters are λmax=585 nm and �=0.94. in contrary to these values, in hc2-containg inclusions λmax=547–556 nm and �=0.59–0.74 are typical. the parameters of the crude oil are similar to the λmax and q values of hc2-containing inclusions, but they are both a little bit lower, being λmax=548 nm and �=0.55. the fluorescent properties of the measured hc fluid inclusions display a systematic blue shift towards shorter wavelengths during the hc migration and trapping. the modeling procedure of the trapped petroleum fluid, microthermometric (th of the selected petroleum inclusion; 120 °c) and its volumetric data (the volume fraction of the vapour phase of 0.091 at 43 °c) were used. in order to control the effects resulting in possible inaccuracy of the phase ratio estimation on pressure estimation, compositional modeling was also performed using the overand underestimated volume ratios. additionally, the raw fluid model composition has been refined using typical petroleum fluids of known composition (α-β) values of the fit-oil software (montel, 1993). the software calculates isopleths and isochores based on the peng–robinson equation of state (peng & robinson, 1976). in order to validate the computational procedures, we have compared a physical property (api gravity) of the modeled petroleum and produced crude oil using the approach of bodnar (1990). to obtain the trapping pressure, the intersection of the isochore of the modeled petroleum fluid with the trapping temperature has to be located in a p-t space (thiéry et al. (2002) and references therein) (fig. 10). as mentioned above, the earliest zone of the hc2 inclusions (hc2_p1) is probably co-genetic with the a�_p2 inclusions. munz (2001) suggests that if textural criteria indicate co-genetic trapping of petroleum and aqueous inclusions, methane saturation of the aqueous inclusions can be assumed, and the aqueous homogenisation temperature represents the trapping temperature for both types of inclusions. inclusions of the (aq_p2) primary aqueous inclusion assemblages undergo homogenization to liquid (laq+v→laq) at 129 to 149 °c (in üllés-61) and at 131 to 142 ºc (in üllés-65a), so these temperature intervals could be given as trapping temperatures. the minimum value of this interval was chosen for modeling: ttrapping = 130 °c. in order to get the trapping pressure, the isochore of the modeled petroleum fluid was intersected by the line representing the trapping temperature (th,min(aq_p2) = ttrapping = 130 °c) and thus the trapping pressure arises as 153 bar. applying the over and underestimated volume ratios, the calculated trapping pressures are 157 bar and 146 bar, respectively. 5. discussion 5.1. data evaluation after clarification of the sequence of fracture-filling minerals (table 1), the p-t stabilities of all these phases were calculated by the windomino modelling system (de capitani & brown, 1987; de capitani, 1994). the resulting models table 4. the uv fluorescent parameters of hc fluids trapped in fluid inclusions and the crude oil. hc samples lmax q il=500nm il=650nm hc1 585 0.94 138 129 hc2_1 556 0.74 182 135 hc2_2 553 0.61 173 105 hc2_3 547 0.59 179 106 hc2_4 549 0.63 187 119 hc2_5 549 0.66 161 107 crude oil 548 0.55 196 107 table 5. measured volume ratios, estimated trapping temperatures and pressures as well as the calculated gor and api gravity values for a petroleum inclusion trapped in analcime (üllés-61 well). jvap @ 43 °c (vol%) tt (°c) pt (bar) gor (calculated) °api (calculated) 0.091 (measured by clsm) 130 152.7 76.12 37.30 0.082 (–10%) 130 145.64 64.94 36.86 0.10 (+10%) 130 157.32 81.57 38.98 figure 10. phase diagram of the fluid trapped in hc2 petroleum inclusions with the relevant isochore. the calculated trapping temperature and pressure of the hc2-bearing fluid inclusion generation are marked on the diagram. uv-fluorescence micro-spectroscopy confirms that the two different hc inclusion assemblages trapped different oil types, and indicates that the crude oil produced in the field is more similar to the oil trapped in the later formed hc2 fluid inclusion assemblage. api gravities estimated from fluorescence colour are 30–35° for hc1 and 40–45° for hc2 when following the approach outlined in bodnar (1990) (szabó et al., 2012). 4.6. confocal laser scanning microscopy (clsm) the clsm analyses were performed on petroleum inclusions trapped in analcime. the volume of a representative inclusion above the homogenization temperature and the volume of the vapour phase at 43 °c were 52.24 μm3 and 4.75 μm3, respectively. hence, the volume fraction (φvap=vvap/(vvap+vliq)) of the vapour phase at 43 °c is 0.091. as currently, calibrated thresholding procedures on precise volume estimation in minerals are unavailable, we have performed further calculations using overand underestimated volume ratios of 10%. the applied volume ratios are summarized in table 5. 4.7. palaeopressure calculations in order to estimate the pressure conditions during filling of the üllés reservoir, model petroleum compositions were reconstructed using the fit-oil software (thiéry et al., 2002). for g eo lo gi a c ro at ic a geologia croatica 69/3290 could be compared to the estimations of liou et al. (1991) for the p-t stability fields of different zeolites. the temperature estimations could be completed by the homogenization temperatures from fluid inclusion microthermometric measurements (table 3). in addition, the sequence of zeolites could be used as an indicator of changing palaeo-temperature conditions, as it was previously reported from different volcanic provinces (coombs et al., 1959; neuhoff et al., 1997; jorgensen, 2006). barth-wirsching & höller (1989) confirm that in order to compare zeolite zonation patterns, choosing a reference area with similar chemical compositions is crucial. the formation of zeolite zones could be associated with geothermal areas or could be the result of a burial diagenetic alteration of the basaltic wall rock. the zeolite zones in fractured basaltic rocks observed in the faeroe islands (jorgensen 2006), iceland (walker, 1960; weisenberger & selbekk, 2009), and in east greenland (neuhoff et al., 1997) are as follows: thomsonitechabazite, analcime, mesolite-scolecite, heulandite-stilbite and laumontite from the surface down to greater depths and higher temperatures. the borehole temperature measurements at these fractured and zeolite-cemented volcanic rocks (jorgensen, 2006) could also give estimations for the usual precipitation temperature of different zeolites. in some places chlorite aggregates occur among the late laumontite crystals in lmt-type veins, but they were not suitable for chlorite thermometry. however, applying thermometry to chlorite crystals in the vesicles, the subsequent chlorite generations (from chl1 to chl4) gave an increasing temperature trend from about 140–185 °c to a maximum of 205–220 °c using different chlorite thermometers (szabó et al., 2009b). if the chlorites in the vesicles and in the lmt-type veins were precipitated simultaneously, then the chlorite thermometry data would suggest that laumontite crystallization could occur at temperatures as high as 205–220 °c. this datum, nevertheless, was not strengthened by the vitrinite reflectance data in the local area measured on marl samples from the emf. the ro data (0.53–0.79 %) show the upper border of the mid-mature oil zone with a temperature lower than 160 °c (szabó et al., 2009a; dolton, 2006). so, the subsequent chlorite generations in the vesicles could alternatively be the product of a very early reheating event in the rock mass. consequently, the peak temperature suggested by chlorite thermometry must be independent of the temperature data from vein-filling zeolite minerals, and the subsequent chlorite generations in the vesicles do not correspond with the chlorite of the lmt-type veins. in the successive zeolites of the anl-type veins, initially the dominant cation was sodium, whereas later calcium gradually became dominant. the aqueous inclusions trapped in the first precipitated analcime (aq_p1 inclusions) go to homogenization at around 124–145 °c, which could be regarded as the minimum temperature of their trapping (diamond, 2003). analcime includes some fibre shaped crystals of mesolite trapped before (but never after) the formation of late aq_p2 inclusion assemblages. mesolite usually indicates a higher temperature-pressure environment than the analcime (jorgenson, 2006). this episodic mesolite precipitation could be the sign of small temperature fluctuations and/or chemical changes in the pore fluid at the time of analcime precipitation. heulandite also contains mesolite fibreaggregates as inclusions in very large quantities. this suggests that mesolite precipitation predated the heulandite, which crystallized on mesolite fibres. the position of heulandite in the zeolite sequence suggests higher pressure and temperature in the fractures at the time of heulandite precipitation, which also is strengthened by windomino calculations (140–190 °c) and estimations from liou et al. (1991) (140–170 °c). the closing mineral of the sequence is stilbite, which probably crystallized below 140 °c based on the windomino model. the syntaxial microstructure of the anl-type veins refers to a fluid dominant system in the fractures during the precipitation of the minerals. the trend of temperature changes could not be given unequivocally, but the temperatures of mineral precipitations in this anl-vein type were presumably lower than the formation temperature of laumontite in the lmt-type veins (150–225 °c; szabó et al., 2009b). based on fluid inclusion petrographic observations, from all of the vein types only the anl-type contains petroleum inclusions. using the fit-oil software the estimated trapping pressure of petroleum inclusions varies at about 150–160 bar. 5.2. subsidence history based on different thermometric data of the subsequent vein types (szabó et al., 2009b), the post-volcanic temperature evolution and the subsidence history of the volcanic rocks could be modelled in the study area (fig. 11). based on all of the textural features of the basalt, and the presence of intercalated marl layers and marl inclusions in the pyroclasts in both the ruzsa and the üllés wells, a subaqueous character is suggested for the volcanism (balázs & nusszer, 1987; szabó et al., 2009b), and this involves rapid cooling and intensive metasomatism of the rock. the fractures in the lapilli and in the massive basalt, where the minerals of kfp-type and cal-type veins precipitated, were presumably the results of early cooling of the rock shortly after volcanism in the area (szabó et al. (2009b)). the minerals of kfp-veins precipitated in fractured lapilli before the final consolidation of the volcanic sediment at around 140–155 °c. the calcite of cal-type veins crystallized in the fractures of basalt, which were previously filled by altered volcanic material. the subsequent chlorite generations in the vesicles – giving an increasing temperature trend from about 140–185 °c to a maximum of 205–220 °c (szabó et al., 2009b) – could be the product of a very early reheating event in the rock mass. after consolidation, the earliest cement phases in some of the lmt-type veins from prehnite via early laumontite to thomsonite clearly suggest a cooling trend during fracture cementation from around 130–180 °c down to 50–90 °c. however, the next, late laumontite phase suggests a higher temperature for the late evolution to the temperature of 150–225 °c on the basis of the temperature stability of laumontite. most of the lmt-type veins contain only late laumontite and calcite suggesting that most of the veins opened at this time. this reheating event (from 50–90 °c up to around 150–225 °c) in lmt-veins could be the result of some post-volcanic reheating effect that worked by circulating hot hydrothermal fluids in the newly opened or re-opened veins. the late calcite cement of the lmt-type veins does not yield any valuable information about the temperature of precipitation, but contains secondary aqueous inclusions, which give 135–150 °c as homogenization temperature suggesting a light, late cooling in this type of vein. vitrinite reflectance data (ro=0.53–0.79%) in the local area measured on marl samples of emf show the upper boundary of the mid-mature oil zone with a temperature lower than 160 °c (szabó et al., 2009a). so the reheating could reach a maximum of 160 °c in the marl of the local area. the presumably youngest anl-type veins only occur over a restricted area, and their vein-filling minerals (anl, heu, stb) indicate about 125–145 °c as the precipitation temperature without any sharp spatial or temporal trend. the palaeopressure calculag eologia c roatica szabó et al.: palaeofluid evolution in a fractured basalt hosted reservoir in the üllés-ruzsa-bordány area, southern sector of the pannonian basin 291 tions with the trapping temperature of 130 °c gave 150–160 bar as estimated for the time of hc2 petroleum fluid appearance in the fractures of anl-type. this corresponds to 1500–1600 m maximum subsidence using hydrostatic pressure at the time of hydrocarbon migration. therefore the trapping of hc2 fluid occurred at a temperature of 130 °c and 150–160 bars, i.e. at 1500– 1600 m depth. using the above data, the estimated geothermal gradient seemed to arise ca. 86 °c/km during cementation of the anl-type veins and hc2 fluid migration. although at first sight, this value seems to be a strong underestimation of the real trapping pressure,such an elevated geothermal gradient (70 °c/km) is not uncommon in the pannonian basin even recently (solevic et al., 2006). the above mentioned, extremely high thermobaric gradient queries the reliability of the applied pressure estimation as well as raising the possibility of alternative scenarios for fracture cementation and fluid migration. the previous results of szabó et al. (2009a) concerning the maturity parameters based on vitrinite reflectance and rock-eval pyrolysis measurements suggest that the intercalated marl bodies of the emf in the local area barely reached the oil window and hence were unable to produce a significant amount of hydrocarbon (oil). it follows that the analcime-hosted hc2 fluid probably did not form in-situ but most probably migrated from adjacent, deeper sub-basin(s) with higher p-t properties and sufficient organic matter. as shown in table 4, the spectral parameters of the produced oil and the analcime-hosted hc2 fluid are practically identical. additionally, szabó et al. (2012) compared the produced oil and the analcime-hosted hc2 using detailed organic geochemical analyses. they revealed that in terms of the point of maturity and type of source rock the fluids are also extremely similar. hence, it can be assumed that the hc2 fluid inclusions enclosed a hydrocarbon fluid that is identical in most parameters with the produced oil. considering that the trapping temperature (ca. 130 °c) of the hc2 fluid inclusion assemblages corresponds to that which reigns at their present depth in the reservoir, it could be assumed that the trapping of the hc2 fluid inclusions could be roughly at their recent position. so, the trapping pressure should fall near to the present formation pressure (ca. 250 bar) instead of that suggested by the fit-oil modeling (150–160 bar). that is, in the present case this approach is not appropriate to estimate the trapping pressure. the hypothetical subsidence curve of the rocks was constructed mainly using maximum temperatures obtained from the applied thermometers, however, at least for the youngest vein type; alternative scenarios would also be envisaged. the anl-type veins only occur over a restricted area and moreover represent an exotic chemical system, namely, sodium as a dominant cation instead of calcium as was usual in the vein system. additionally, the crosscutting relationship of the lmt and anl-type is still unclear. taking into consideration the afore-mentioned information as well as the fact that the stability field of laumontite is quite extended and includes the formation temperature of the analcime phase as well, it can be presumed that with changing physicochemical conditions (as well as the arrival of petroleum-bearing fluids), the evaluation of the vein system can be explained in a slightly different way too. since this alternative scenario, the formation and cementation of anl-type veins might have predated or they could have even formed and cemented coevally with the lmt-type. the previous scenario is improbable, because there is not any evidence for oil migration during crystallization of lmt-type veins. 5.3. the stages and the timing of petroleum migration based on fluid inclusion petrographic observations, from all of the vein types only the anl-type contains petroleum inclusions, while methane-bearing fluid inclusion assemblages also occur in other vein types. based on fluorescent parameters, two kinds of petroleum fluids could be distinguished trapped within inclusions. at first yellow-fluorescent petroleum (hc1) was trapped during the precipitation of early growth zones of analcime, which was afterwards followed by the trapping of a petroleum fluid (hc2) with a visually intense green fluorescent colour. the blueshifted nature of the hc2 fluid relative to the hc1 petroleum suggest the occurrence of a thermally more mature and/or less degraded fluid (stasiuk & snowdon, 1997) in the pore space figure 11. a temperature-subsidence evolution model of the fractured volcano sediment rock body in the üllés area. the governing events are indicated by boldface type and the applied thermometers by italics. g eo lo gi a c ro at ic a geologia croatica 69/3292 with time. considering the fluorescence colours both fluid inclusion oils seem to have a slightly immature character. based on the fluorescence parameters, the estimated api gravities are 30–35° for hc1 and 40–45° for hc2 petroleum fluids (szabó et al., 2012), where a lower api gravity (a higher density) usually relates to a lower maturity in the case of the hc1 fluid. the studied crude oil (produced oil) shows very similar fluorescent characteristics to the hc2 fluid trapped in the fluid inclusions (table 4) suggesting that they are sampled from a very similar fluid migrated in the fracture network and the adjacent vesicular pores of the basaltic host rock. the slightly immature character of both oils (or the lack of overmature oils) – as presented by the estimated api gravities – suggests that at the time of migration and trapping, the fluids were not affected by extreme heating. this means that the oil migration and trapping occurred at lower temperatures than the precipitation of lmt in lmt-type veins. the appearance of liquid hc-containing fluids in the pore space would have to have occurred either after cementation of the three early vein types (kfp-, caland lmt-type veins) or in the stage of calcite precipitation in lmt-type veins, but at the time of analcime precipitation in anl-type veins. comparing the microthermometric data from different wells, the aq_p2 and hc2_p1 inclusions have more similar homogenization temperatures in samples from the üllés-61 well than the aq_p2 and hc2 inclusions in samples of the üllés-65/a well with similar number of measurements. this refers to trapping of more gas-saturated liquid in the fractures in the üllés-61 well than in the üllés 65/a well (tseng & pottorf, 2002) (fig. 7). the slight differences in the fluorescent parameters of the crude oil and the petroleum inclusions suggest geochemical differences in their compositions. the detailed biomarker characterization of the captured inclusion oils and the produced oil could correlate the source rock and the oils, and also could reveal the stages of the migration and accumulation that occurred in the area. 6. conclusions the evidence for fracture cementation and fluid evolution that we have presented for the fractured basaltic rocks in the area of üllés-ruzsa are based on complex fluid-inclusion analyses and mineral equilibria calculations. this work focused on the zeolite minerals of the anl-type veins, which occur both as fracture-filling phases in drillcores and as fragments from cuttings. the sequence of the zeolite minerals in anl-type veins is early mes → anl → late mes → heu → stb. based on the equilibrium mineral parageneses at the given stages of the fracture cementation, windomino modeling suggests a decreasing temperature trend with time (190 °c → <140 °c), while no clear trend in pressure could be established with proceeding fracture cementation. the palaeofluid evolution of the igneous/volcano-sedimentary rock body could be traced using the aqueous and hydrocarbon -bearing fluid inclusion assemblages trapped in the analcime and heulandite grains. based on fluid inclusion evidence, we have identified three unequivocally distinct fluid migration events, namely, aq_p1 (aqueous) → hc1_p (hydrocarbon) → aq_ p2+hc2_p1 (aqueous + hydrocarbon). the occurrence of these fluid inclusions along growth zones as well as formation of threephase (laq+lhc+v) fluid inclusions simultaneously with aq_ p2+hc2_p1 fluid inclusion assemblages reveals the above temporal trapping succession of these fluids. in-situ uv-fluorescence analyses on the analcime-hosted hc1 and hc2 hydrocarbon-bearing fluid inclusions as well as on the produced oil of the üllés-65a well, suggest two major phases can be ascertained. namely, the significantly more frequent hc2 petroleum inclusions show characteristic blue-shifted fluorescence properties, i.e. the presence of a more mature fluid relative to hc1. the presence of the hc1 petroleum inclusions along the early growth zones and the supposed lower maturity imply that they probably preserved the remnants of one of the earliest oil migration events in the fracture system. alternatively, the uv-fluorescence properties of the hc2 inclusion oil and the produced oil of the üllés-65a well are practically identical. therefore we assume that at least in the area of the üllés-65a well, the free pore space remains filled (even today), by a hydrocarbon fluid that is reasonably similar to the late hc2 inclusion oil. as the early kfp-, cal-, lmt-type veins do not contain any traces of hydrocarbon fluid remnants we suppose that the filling of the fractured basalt reservoir is coeval with the fracturing and cementation of the anl-type veins. based on microthermometry data of the cogenetic aqueous and hydrocarbon fluid inclusions (aq_p2 and hc2_p1), the migration of the dominant petroleum-bearing fluid took place at 125–145 °c. previous organic geochemical analyses performed on marl samples intercalated with the igneous/volcano-sedimentary rocks as well as on fluid inclusions and produced oil samples revealed that rocks of the endrőd marl formation can be most probably regarded as the source rock of both petroleum fluids. however, the low maturity (ro=0.53–0.79%) of the marl samples in the vicinity of the anl-type veins suggests that the oil formed in adjacent deeper sub-basins and migrated into the fracture system rather than in-situ maturation of the intercalated marl due to the heat effect of the volcanic rocks. nevertheless, the reconstructed palaeo-pressure that was characteristic during migration of the hc2 oil is remarkably high (86 °c/km) suggesting the reign of an elevated heat flow during this period of basin evolution. acknowledgement the authors thank mol ltd. for their financial support of the project. special thanks go to róbert gyurcsányi (budapest university of technology and ecomics) for his help with uv fluorescent micro-spectroscopy and andrás szabó (budapest university of technology and ecomics) and eric le menn (university of nantes) for their help in the raman micro-spectrometric measurements. the research was supported by hungarian national scientific research fund (otka, k 108375). references aplin, a.c., macleod, g., larter, s.r., pedersen, k.s., sorensen, h. & booth, t. (1999): combined use of confocal laser scanning microscopy and pvt simulation for estimating the composition and physical properties of petroleum in fuid inclusions.– mar. petrol. geol., 16, 97–110. badics, b., uhrin, a., vető, i., bartha, a. & sajgó, cs. (2011): basin-centred gas in the makó trough, hungary: a 3d basin and petroleum system modelling investigation.– petrol. geosci.,17, 405–416. badics, b. & vető, i. (2012): source rocks and petroleum systems in the hungarian part of the pannonian basin: the potential for shale gas and shale oil plays.– mar. petrol. geol., 31, issue 1, 53–69. bakker, r.j. & brown, p.e. (2003): computer modeling in fluid inclusion research.– in: samson, i., anderson, a. & marshall, d. (eds.): fluid inculsions – analysis and interpretation. mineral assocication of canada, 175 p. balázs, e. & nusszer, a. (1987): magyarország medenceterületeinek kunsági (pannóniai s. str.) emeletbeli vulkanizmusa [volcanism in the hungarian basins in the time of kunsagi (pannonian .s. str.) – in hungarian].– a magyar állami földtani intézet évkönyve, 69, 95–113. bart-wirsching, u. & höller, h. (1989): experimental studies on zeolite formation conditions.– eur. j. mineral., 1, 498–506. bodnar, r.j. (1990): petroleum migration in the miocene monterey formation, california, usa: constraints from fluid-inclusion studies.– mineral. mag., 54, 295–304. g eologia c roatica szabó et al.: palaeofluid evolution in a fractured basalt hosted reservoir in the üllés-ruzsa-bordány area, southern sector of the pannonian basin 293 bodnar, r.j. (1993): revised equation and table for determining the freezing point depression of h2o-nacl solutions.– geochim. cosmochim. ac. (united states), 57, 3 p. bons, p.d. (2000): the formation of veins and their microstructures.– journal of the virtual explorer, 2. bourdet, j., pironon, j., levresse, g. & tritlla, j. (2010): petroleum accumulation and leakage in a deeply buried carbonate reservoir, níspero field (mexico).– mar. and petrol. geol., 27, 126–142. burke, e.a.j. (1994): raman microspectrometry of fluid inclusions: the daily practice. fluid inclusions in minerals: methods and applications.– in: de vivo, b. & fre­ zotti, m.l. (eds.): short course of the ima working group „inclusions in minerals”, virginia tech (pontignano – siena, 1–4 september, 1994). coombs, d.s., ellis, a.j., fyfe, w.s. & taylor, a.m. (1959): the zeolite facies, with comments on the interpretation of geothermal syntheses.– geochim. cosmochim. ac., 17, 53–107. cserepesné, m.b. (1978): a kiskunhalas­ny­3. szénhidrogénkutató fúrással feltárt alsó­pannóniai bazalt és proterozoi migmatit képződményekről [the basaltic and proterozooic magmatic rocks of kiskunhalas-ny-3 hydrocarbon exploration well – in hungarian].– földtani közlöny, 108/1, 53–64. de capitani, c. (1994): gleichgewichts­phasendiagramme: theorie und software.– beihefte zum european journal of mineralogy, 72. jahrestagung der deutschen mineralogischen gesellschaft, 6, 48. de capitani, c. & brown, t.h. (1987): the computation of chemical equilibrium in complex systems containing non-ideal solutions.– geochim. cosmochim. ac., 51, 2639–2652. diamond, l.w. (2003): systematics of h2o inclusions.– in: samson i., anderson, a. & marshall, d. (eds.): “fluid inclusions: analysis and interpretation” short course, volume 32. mineralogical association of canada, 55–79. diamond, l.w. (2003): glossary: terms and symbols used in fluid inclusion studies.– in: samson i., anderson, a. & marshall, d. (eds.): “fluid inclusions: analysis and interpretation” short course, volume 32. mineralogical association of canada, 363–372. dolton, g.l. (2006): pannonian basin province, central europe (province 4808) ­ petroleum geology, total petroleum systems, and petroleum resource assessment. usgs, reston, virginia. farooqui, m.y., hou, h., li, g., machin, n., neville, t., pal, a., shrivastva, c., wang, y., yang, f.,yin, c., zhao, j., yang, x. (2009): evaluating volcanic reservoirs.– oilfield review, 21/1, 36–47. george, s.c., krieger, f.w., eadington, p.j., quezada, r.a., greenwood, p., eisenberg, l.i., hamilton, p.j. & wilson, m.a. (1997): geochemical comparison of oil­bearing fluid inclusions and produced oil from the toro sandstone, papua new guinea.– org. geochem., 26, 3–4, 155–173. goldstein, r.h. (2003): petrographic analysis of fluid inclusions.– fluid inclusions: analysis and interpretation, 32, 9–54. grimmer, j.o.w., pironon, j., teinturier, s. & mutterer, j. (2003): recognition and differentiation of gas condensates and other oil types using microthermometry of petroleum inclusions (abstract).– j. geochem. explor., 78–79, 367–371. haas, j., budai, t., csontos, l., fodor, l. & konrád, gy. (2010): ma­ gyarország pre­kainozoos földtani térképe, 1:500 000.– magyar állami földtani intézet kiadványa, budapest. holland, t.j. & powell, r. (1998): an internally consistent thermodynamic data set for phases of petrological interest.– j. metamorph. geol., 16, 309–343. jørgensen, ø. (2006): the regional distribution of zeolites in the basalts of the faroe islands and significance of zeolites as paleotemperature indicators.– in: chalmers, j.a. & waagstein, r. (eds.): scientific results from the deepened lopra­1 borehole, faroe islands. geol. surv. den. greenl., 9, 123–144. karlsen, d.a., nedkvitne, t., larter, s.r. & bjørlykke, k. (1993): hydrocarbon composition of authigenic inclusions: application to elucidation of petroleum reservoir filling history.– geochim. cosmochim. ac., 57, 15, 3641–3659. liou, j.g., de capitani, c. & frey, m. (1991): zeolite equilibria in the system caal2si2o8 – naalsi3o8 – sio2 – h2o.– new zeal. j. geol. geop., 34, 293–301. magoon, l.b. (2004): petroleum system: nature’s distribution system of oil and gas.– in: cleveland, c. (ed.): encyclopedia of energy, vol. 4., elsevier (academic press), 823–836. magyar, i., geary, d.h., sütő­szentai, m., lantos, m. & müller, p. (1999): integrated biostratigraphic, magnetostratigraphic and chronostratigraphic correlations of the late miocene lake pannon deposits.– acta geol.hungarica, 42/1, 5–31. magyar, i., juhász, gy., szurominé korecz, a. & sütőné szentai, m. (2004): a pannóniai tótkomlósi mészmárga tagozat kifejlődése és kora a battonya­pusztaföldvári­hátság környezetében [the tótkomlós calcareous marl member of the lake pannon sedimentary sequence in the battonya-pusztaföldvár region, se hungary – in hungarian with an english abstract].– földtani közlöny, 134/4, 521–540. montel, f. (1993): phase equilibria needs for petroleum exploration and production industry.– fluid phase equilibr., 84, 343–367. munz, a.i. (2001): petroleum inclusions in sedimentary basins: systematic, analytical methods and applications.– lithos, 55, 195–212. neuhoff, p.s., watt, w.s., bird, d.k. & pedersen, a.k. (1997): timing and structural relations of regional zeolite zones in basalts of the east greenland continental margin.– geology, 25, 803–806. oliver, n.h.s. & bons, p.d. (2001): mechanisms of fluid­flow and fluid­rock interaction in fossil metamorphic hydrothermal systems inferred from vein-wall rock patterns, geometry and microstructure.– geofluids, 1, 137–162. oxtoby, n. (2002): comments on: assessing the maturity of oil trapped in fluid inclusions using molecular geochemistry data and visually­determined fluorescence colours.– appl. geochem., 17, 1371–1374. pap, s. (1983): alsó­pannóniai bazalt vulkanizmus balástya és üllés­ruzsa­zákányszék térségében [lower pannonian basalt volcanism in the balástya and üllés-ruzsazákányszék areas – in hungarian].– földtani közlöny, 113/2, 163–170. peng, d.y. & robinson, d.b. (1976): a new two­constant equation of state.– ind. eng. chem. fundam., 15, 59–64. pironon, j., canals, m., dubessy, j., walgenwitz, f. & laplace­builhe, c. (1998): volumetric reconstruction of individual oil inclusions by confocal scanning laser microscopy.– eur. j. mineral., 10, 1143–1150. schubert, f., diamond, l.w. & m. tóth, t. (2007): fluid­inclusion evidence of petroleum migration through a buried metamorphic dome in the pannonian basin, hungary.– chem. geol., 244, 357–381. shepherd, t.j., rankin, a.h. & alderton, d.h.l. (1985): a practical guide to fluid inclusion studies.– blackie and son ltd., 239 p. solevic, t., stojanovic, k., jovancicevic, b., mandic, g., schwarzbauer, j. & vitorovic, d. (2006): multivariate statistical methods applied to interpretation of saturated biomarkers (velebit oil field, se pannonian basin, serbia).– j. serb. chem. soc, 71/7, 745–769. stasiuk, l.d. & snowdon, l.r. (1997): fluorescence micro­spectrometry of synthetic and natural hydrocarbon fluid inclusions: crude oil chemistry, density and application to petroleum migration.– appl. geochem., 12, 229–241. szabó, b., hetényi, m., schubert, f., milota, k. & m. tóth, t. (2009a): repedezett bazaltanyagú szénhidrogén rezervoárok üllés­bordány térségében. [fractured basaltic hydrocarbon reservoirs in üllés-bordány area – in hungarian].– in: m. tóth, t. (ed.): magmás és metamorf képződmények a tiszai egységben, geolitera, 1–9. szabó, b., schubert, f. & m. tóth, t. (2009b): paleofluid evolution of the fractured basalt hydrocarbon reservoir in the üllés­ruzsa­bordány area, se hungary.– central european geology, 52/3–4, 299–323. szabó, b., schubert, f., volk, h. & manzur, a. (2012): fluid inclusion ana­ lysis as additional tool for comprehension of petroleum systems: a case study from the pannonian basin (hungary).– aapg search and discovery article #40917, aapg annual convention and exhibition, april 22-25, 2012, long beach, california. thiéry, r., pironon, j., walgenwitz, f. & montel, f. (2002): individual characterization of petroleum fluid inclusions (composition and p­t trapping conditions) by microthermometry and confocal laser scanning microscopy: inferen ces from applied thermodynamics of oils.– mar. petrol. geol., 19, 847–859. walker, g.p.l. (1960): zeolite zones and dike distribution in relation to the structure of the basalts of eastern iceland.– j. geol., 68, 515–528. weisenberger, t. & selbekk, r.s. (2009): multi­stage zeolite facies mineralization in the hvalfjördur area, iceland.– int. j. earth sci., 98, 985–999. whitney, d.l. & evans, b.w. (2010): abbreviations for names of rock­forming minerals.– am. mineral., 95, 185–187. wyszecki, g. & stiles, w.s. (2000): color science: concepts and methods, quantitative data and formulae.– john wiley and sons, 2nd edition, 156 p. 2019 | 72 / special issue | 19–32 | 15 figs. | 3 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society article history: manuscript received may 13, 2019 revised manuscript accepted august 28, 2019 available online december 20, 2019 keywords: diabase, ganzi-litang ocean, luoji, early permian, western yunnan 1. introduction continental rift basalt (crb) is one of the key geological records for understanding the mechanism and process of continental rifting (e.g., frey et al., 1978; sun & mcdonough, 1989; macdonald et al., 2001; cui et al., 2015; ma et al., 2017). in rift environments, due to the interaction between tectonics and magmatism, the continental lithosphere usually undergoes substantial thinning, which inevitably leads to the upwelling of mantle magma (hawkesworth et al., 1993; wang et al., 2002; cui geochemistry and u-pb ages of the diabases from the luoji area, western yunnan, china: implications for the timing of the initial rifting of the ganzi-litang ocean chan wang1,2, hao liu2,3,*, hanbin feng4, jianghong deng1, xianfan liu1 and fufeng zhao1 1 chengdu university of technology, college of earth sciences, chengdu, sichuan, 610059, china 2 school of environment and earth science, university of queensland, brisbane, qld, 4072, australia 3 chengdu university of technology, college of energy, state key laboratory of oil and gas reservoir geology and exploitation, chengdu sichuan, 610059, china 4 north china petroleum administration co., ltd. sulige exploration and development branch, shijiazhuang, hebei, 017300, china (*correspondence author: hao liu, 277515537@qq.com) doi: 10.4154/gc.2019.25 abstract detailed geochemical and u-pb studies of two diabases (luoji and cuiyi) from the luoji area have been undertaken. the diabases are high-k calc-alkaline and belonging to the tholeiitic series, enriched in large ion lithophile elements, ti, zr and light rare earth elements, and depleted in high field strength elements. these characteristics are different from the oceanic island basalt but highly consistent with the continental rift basalt, indicating the luoji and cuiyi diabases are the products of the intracontinental rift related to the initial opening of the ganzi-litang ocean. the luoji and cuiyi diabases originated from an enriched mantle source with a small degree of crustal contamination during their emplacement. zircon u-pb ages show that the luoji and cuiyi diabases were emplaced at 293.4±5.4ma. therefore, we propose that the time of initial rifting of the ganzi-litang ocean occurred during the very early permian. et al., 2015; khoshnoodi et al., 2017; zhou et al., 2018). consequently, at the beginning stage of rifting, mantle-derived magmas with signatures of crb will emplace along the tensioned weak zone of a continental rift belt (macdonald et al., 2001; cui et al., 2015; szabó et al., 2016). a crb is crucial to the study of the continental within-plate tectonic movement and the initial evolution of the ocean basin as it has a fundamental role in constraining the initiation time of the ocean opening (lassiter & depaolo, 1997; jung & masberg, 1998; cui et al., 2015). figure 1. location of the western yunnan in china (a), geotectonic location map (b) and regional geological map of the luoji diabase in western yunnan province (c) (after hou et al., 2001). g eo lo gi a c ro at ic a geologia croatica 72 / special issue20 the initial opening time of the ganzi-litang ocean has always been controversial. in order to reveal the process of tectonic evolution with the ganzi-litang ocean, mafic diabases developed in the ganzi-litang suture zone of tibet have been extensively studied by earlier researchers (e.g., hou et al., 2001; ybgmrrgst, 2003; liang et al., 2018). however, most of the reported diabases are oceanic island basalts (oib) or mid-ocean ridge basalts (morb) (hou et al., 2001). hence, the time of initial rifting of the ganzi-litang ocean is still not well constrained. in this research, we conducted whole-rock geochemistry and zircon u-pb dating analysis of two diabases (luoji and cuiyi) from the luoji area, the southern segment of the ganzi-litang suture zone. the diabases in this study show typical crb characteristics, hence can be used to constrain the initial evolution of the ganzi-litang ocean. 2. geological background and lithofacies characteristics the luoji and cuiyi diabases are located in the luoji country in the northwestern part of shangri-la county, yunnan province, sw china. they are a part of the ganzi-litang ocean basin and located at the junction of the western margin of the yangtze block, the zhongzan-zhongdian continental block and the yidun island arc belt (fig. 1a). magmatic activities in this area mainly occurred during permian to triassic time (hou et al., 2001; ybgmrrgst, 2003; liang et al., 2018). most of the ultrabasic-basic rocks have been deformed and transformed due to multi-stage tectonic movements. during the continental collision stage, most of the ultrabasicbasic rocks occur in the form of a mélange (ybgmrrgst, 2003). the ultrabasic rocks in the study area occur in the lower permian mushengtu formation. most of the basic rocks are diafigure 2. (a) outcrop of diabase with a diabasic texture; (b) photomicrograph of diabase (cross-polarized light). ilm-ilmenite; pl-plagioclase; di-diopside; aug-augite; q-quartz. figure 3. zircon u-pb concordia diagrams for the luoji diabase. g eologia c roatica wang et al.: geochemistry and u-pb ages of the diabases from the luoji area, western yunnan, china: implications for the timing of the initial rifting ... 21 base dykes cropping out in the lapoli, sijiagou and zhangjia areas. the dykes are distributed in nw-se direction with a width ranging from tens of centimetres to a few metres and they extend for hundreds of metres. the diabases intruded into the mushengtu formation and the lower permian luoji formation (ybgmrrgst, 2003). the luoji and cuiyi diabases are dark gray-grayish green (fig. 2a), fineto medium-grained (0.2~2mm.) with a diabasic texture. the rocks are composed of plagioclase (75~79%), augite (5~8%), diopside (2~5%) and quartz (1%) with accessory minerals of apatite, magnetite and ilmenite (fig. 2b). 3. samples and methods rock samples for this study were collected from outcrops. only the fresh to least-altered samples were selected on the basis of hand lens observations for further analysis by thinsection. major and trace elements were analyzed at the metallurgical geological rocks and ore testing center, sichuan, china. for major element analyses, powder samples (grain size less than 200 mesh) were fluxed with li2b4o7 (1:8) to make homogeneous glass discs at 1,250°c using a v8c automatic fusion machine. the bulk rock major elements were analyzed on fused glass discs with a zetium (panalytical) sequential x-ray fluorescence spectrometer. the loss on ignition (loi) of sample powders was determined at a temperature of 1,000°c. the measurements were monitored using the standards gsr-3 (xie et al., 1989) and bhvo-2 (raczek et al., 2010), and the accuracy of the analytical results was controlled by measuring the standard reference material bhvo2. the analytical errors for the major element analyses were better than 2%. trace element analyses were conducted using inductively coupled plasma mass spectrometry (icp-ms) (thermal x series ii). during the digestion procedure, 25 mg of sample powder was precisely weighed and transferred into screw-top teflon beakers. then 1.5 ml hf and 1.5 ml hno3 were added in turn and heated in the closed teflon beakers at 100°c for 96 hours, subsequently opened and heated at 120°c to evaporate the dissolution. then, 0.5 ml hf and 2.5 ml 1:1 hno3 were added, and the beakers were transferred to a digestion bomb. the bombs were heated in an oven at 170°c for 72 hours, after which the beakers were opened and heated at 120°c to evaporate the dissolutions. the residues were added to 1:1 hno3, sealed and heated at 120°c for 30 min. figure 4. (a) sio2 (wt.%) vs. na2o+k2o (wt.%) diagram (after pearce, 1979); (b) sio2 (wt.%) vs. k2o (wt.%) diagram (after maniar & piccoli, 1989); (c) whole-rock alkali (na2o+k2o) vs. tfeo vs. mgo (afm) plot for luoji and cuiyi samples (after irvine & barager, 1971). g eo lo gi a c ro at ic a geologia croatica 72 / special issue22 the solutions were then diluted 1,000 times using 2% distilled super-pure hno3 and analyzed using icp-ms with in, rh and re as inner standards. the standard solutions (american lab tech company) were diluted to 1 μg l-1, 10 μg l-1, 50 μg l-1, and 100 μg l-1 to produce the calibration curve, with linear regression coefficients all above 0.9999. the bhvo-2 and gsr-3 were run as external standards to evaluate the accuracy. analytical precision for most elements is better than 3%. in order to constrain their emplacement time, zircon grains were handpicked from the diabases under a binocular microscope after conventional heavy liquid and magnetic separation, and then mounted in an epoxy resin. the sample mount was polished to expose the centres of the zircons. all of the grains were photographed under transmitted and reflected light and then examined using cathodoluminescence (cl) imaging to observe the internal structures of the zircons. u-pb analyses of the zircons were carried out using an agilent technologies 7700x quadrupole icpms equipped with a 193 nm arf excimer laser at the institute of geophysical geochemistry, chinese academy of geological sciences, beijing. the laser beam was focused on the sample with a fluency of 5.0 j/cm2 and a spot of 40 μm diameter at a repetition rate of 5 hz for 50 s. helium was used as a carrier gas to transport the ablated aerosol to the mass-spectrometer. zircon nancy 91500 (wedenbeck et al., 1995) was used as an external calibration standard to correct for instrumental mass bias and elemental fractionation. the standard gj-1 (jackson et al., 2004) was simultaneously analyzed which yielded ages consistent with the recommended values within analytical error. the pb content of the zircon was externally calibrated against nist srm 610 with si as an internal standard, whereas other trace elements were measured with zr as an internal standard (hu et al., 2011). rawdata reduction was performed off-line using the icpmsdatacal (liu et al., 2010). concordia diagrams and weighted average calculations were made using isoplot 3.0 (ludwig, 2012). uncertainties in individual analyses are reported at the 1σ level, and the average ages for pooled u-pb analyses are quoted at 95% confidence. 4. results 4.1. zircon u-pb dating cathodoluminescence (cl) images of representative zircon grains are shown in figure 3. and la-icp-ms zircon u-pb data are presented in table 1. twenty-one zircon grains from the diabases are mostly euhedral to subhedral, with lengths of 40-100μm and length-to-width ratios of 1:1 to 3:1, and have weak oscillatory zones indicating a magmatic origin. zircon grains from the luoji diabase have u contents of 215–1502 ppm (average 647.29), th contents of 45–5824 ppm (average 1421.67) and th/u ratios from 0.11 to 5.80 (table 3), indicating they are of magmatic origin. the single spot ages vary from 1907±17ma to 291±4ma with three distinctive peaks of 1245ma~1028ma, 901ma~757ma and 303ma~291ma. for the youngest set of data, the spots yield a 206pb/238u weighted mean age of 293.4±5.4ma (fig. 3b, mswd=1.7, n=5), which indicate that the diabase was emplaced during the early permian. 4.2. major elements as shown in table 2, the loi values of the luoji and cuiyi diabases are between 0.41% and 4.87%. the luoji diabase may be slightly affected by alteration, so the normalized calculation is carried out after deducting the loi (irvine & baragar, 1971). luoji diabase samples contain 48.86~50.89 wt.% sio2 (ave rage 49.68 wt.%), 1.28~2.09 wt.% k2o (average 1.57 wt.%), 2.55~3.36 wt.% na2o (average 2.90 wt.%), 0.16~0.43 wt.% p2o5 (average 0.33 wt.%), 3.68~4.01 wt.% tio2 (average 3.82 wt.%), 9.42~13.06 wt.% feo (average 10.51 wt.%) and 4.17~6.12 wt.% mgo (average 5.11 wt.%) with high na2o/k2o (1.88 on average) and feo/mgo (2.10 on average) ratios, and low mg# values of 0.40~0.52 (0.46 on average). samples of cuiyi diabase contain relatively lower sio2 (46.95~48.63 wt.%, 47.96 wt.% on average), k2o of 0.68~1.42 wt.% (average 1.14 wt.%), tio2 of 2.56~2.79 wt.% (average 2.64 wt.%), feo of 7.81~9.27 wt.% (average 8.46 wt.%), and higher na2o of 2.97~3.60 wt.% (average 3.23 wt.%), p2o5 of 0.13~0.56 wt.% (average 0.34 wt.%), and slightly high na2o/k2o (3.03 on average) and feo/mgo (1.48 on average) ratios, mgo of 5.16~6.34 wt.% (average 5.78 wt.%) and mg# values of 0.50~0.57 (average 0.55) than luoji diabase samples. in the sio2 vs. k2o+na2o diagram (fig. 4a), all samples plot in the basalt field and are distributed along the line of the alkaline-subalkaline series. they are calc-alkaline to high-k calcalkaline in composition (fig. 4b) and belong to tholeiite types (fig. 4c). the high p2o5 contents of the luoji and cuiyi diabases indicate their magma may originate from an enriched mantle (campbell & griffiths, 1993). 4.3. rare earth elements rare earth element compositions of the samples in the study are shown in table 3. total ree values of the diabase samples range from 163.65 ppm to 301.07 ppm (average 219.90 ppm) with lree/ hree ratios of 6.69~9.52. these samples are enriched in lree and show high lree/hree fractionation ((la/yb) n=11.05~12.29, fig. 5a). the normalized ree distribution patterns are similar to the crb (cui et al., 2015). the samples show negligible negative to slight positive eu anomalies (δeu=0.93~1.06), suggesting the existence of pyroxene fractional crystallization (sun & mcdonough, 1989; weaver, 1991; middlemost, 1994). 4.4. trace elements the trace element results are shown in table 4. on the primitive mantle-normalized diagram (fig. 5b), the samples show enrichment in the large ion lithophile elements (liles) of rb, ba and k and high field strength elements (hfses) of th, ta and ti, and depletion in sr, u, nb, p and zr. the reason for a slight depletion in k in all samples relative to ba and rb is that ba and rb are prone to enter into k-bearing phases during the processes of magmatic fractional crystallization and differentiation (frey et al., 1978; szabó et al., 2016). the ratios of zr/nb (5.76~6.23), la/ nb (0.95~1.00), th/nb (0.11~0.13) and k/nb (255.51~334.98) in the luoji and cuiyi diabases are similar to the crb but are distinct from the oib (fig. 5b). 5. discussion 5.1. special tectonic setting of the continental rift basalt (crb) based on tectonic settings, basalts can be divided into three types: continental flood basalts (cfb), mid-ocean ridge basalts (morb), and ocean island basalt (oib) (greenough & mcdivitt, 2018). different tectonic settings will produce diabases with distinct characteristics. hence, we can identify and discuss the environment in which diabase occurred with these unique characteristics. major element contents of all samples are g eologia c roatica wang et al.: geochemistry and u-pb ages of the diabases from the luoji area, western yunnan, china: implications for the timing of the initial rifting ... 23 ta bl e 1. l a -ic pm s u -p b is ot op ic d at a fo r g ab br o in th e lu oj i o ph io lit e su ite . sp ot pb u th (p pm ) th /u 20 7 pb /20 6 pb 20 7 pb /23 5 u 20 6 pb /23 8 u 20 7 pb /20 6 pb 20 7 pb /23 5 u 20 6 pb /23 8 u (p pm ) (p pm ) ra tio 1σ ra tio 1σ ra tio 1σ ag e( m a) 1σ ag e( m a) 1σ ag e( m a) 1σ 1 34 32 2 31 4. 36 9 0. 97 6 0. 05 83 0. 00 06 0. 70 96 0. 01 0. 08 82 0. 00 09 54 2 22 54 4 8 54 5 5 2 96 10 30 37 54 .4 53 3. 64 5 0. 06 16 0. 00 31 0. 39 22 0. 01 99 0. 04 62 0. 00 04 66 1 10 8 33 6 17 29 1 2 3 88 73 2 42 43 .8 43 5. 79 8 0. 05 35 0. 00 09 0. 35 54 0. 00 83 0. 04 82 0. 00 08 35 1 37 30 9 7 30 3 5 4 85 11 36 41 14 .9 33 3. 62 2 0. 05 87 0. 00 24 0. 38 17 0. 01 8 0. 04 71 0. 00 09 55 7 88 32 8 15 29 7 5 5 11 9 12 54 58 23 .8 27 4. 64 4 0. 05 45 0. 00 1 0. 34 7 0. 00 7 0. 04 62 0. 00 06 39 1 42 30 2 6 29 1 4 6 11 8 13 92 39 37 .4 11 2. 82 9 0. 05 43 0. 00 02 0. 35 31 0. 00 47 0. 04 72 0. 00 06 38 2 10 30 7 4 29 7 4 7 15 6 65 2 66 9. 34 3 1. 02 7 0. 08 61 0. 00 05 2. 52 89 0. 01 83 0. 21 31 0. 00 17 13 40 11 12 80 9 12 45 10 8 56 43 4 45 .3 53 0. 10 5 0. 06 58 0. 00 07 1. 13 16 0. 01 19 0. 12 47 0. 00 11 80 1 22 76 9 8 75 7 7 9 20 23 5 17 2. 67 8 0. 73 5 0. 05 67 0. 00 1 0. 60 29 0. 01 11 0. 07 71 0. 00 06 48 0 39 47 9 9 47 9 4 10 15 1 59 5 79 .4 33 0. 13 4 0. 09 54 0. 00 13 3. 41 23 0. 05 12 0. 25 94 0. 00 26 15 36 25 15 07 23 14 87 15 11 55 28 2 11 9. 34 2 0. 42 3 0. 07 71 0. 00 07 2. 03 26 0. 02 65 0. 19 13 0. 00 17 11 23 18 11 26 15 11 28 10 12 37 21 5 20 1. 75 6 0. 93 8 0. 07 15 0. 00 17 1. 46 09 0. 03 83 0. 14 81 0. 00 14 97 3 49 91 4 24 89 0 8 13 98 48 4 92 8. 21 5 1. 91 8 0. 07 06 0. 00 27 1. 44 11 0. 05 69 0. 14 81 0. 00 15 94 5 77 90 6 36 89 0 9 14 59 42 1 13 33 .9 81 3. 16 9 0. 05 69 0. 00 06 0. 65 61 0. 00 72 0. 08 37 0. 00 03 48 6 23 51 2 6 51 8 2 15 24 33 5 14 3. 98 3 0. 43 0 0. 06 36 0. 00 4 0. 50 42 0. 03 28 0. 05 75 0. 00 06 72 7 13 4 41 5 27 36 1 4 16 25 8 15 02 20 57 .7 40 1. 37 0 0. 07 32 0. 00 05 1. 51 38 0. 01 4 0. 14 99 0. 00 12 10 20 15 93 6 9 90 1 7 17 58 35 7 52 6. 75 4 1. 47 6 0. 06 38 0. 00 07 1. 09 71 0. 01 36 0. 12 48 0. 00 15 73 4 23 75 2 9 75 8 9 18 13 7 70 8 57 7. 79 9 0. 81 6 0. 08 14 0. 00 05 1. 94 19 0. 01 25 0. 17 29 0. 00 13 12 32 11 10 96 7 10 28 8 19 10 5 47 6 25 1. 13 8 0. 52 8 0. 09 01 0. 00 15 2. 51 59 0. 05 14 0. 20 25 0. 00 23 14 28 32 12 77 26 11 89 13 3 20 23 9 75 0 29 2. 20 0 0. 39 0 0. 11 64 0. 00 1 5. 16 33 0. 05 14 0. 32 18 0. 00 32 19 01 15 18 47 18 17 99 18 21 12 0 28 1 26 8. 46 7 0. 95 5 0. 15 2 0. 00 07 7. 21 57 0. 07 15 0. 34 43 0. 00 3 23 69 8 21 38 21 19 07 17 ta bl e 2. m aj or e le m en ts d at a (w t.% ) f or d ia ba se d yk es . lj -1 lj -2 lj -3 lj -4 lj -5 lj -6 lj -7 lj -8 lj -9 cy -1 cy -2 cy -3 cy -4 cy -5 cy -6 cy -7 si o 2 47 .3 5 46 .8 5 46 .3 2 46 .5 7 47 .6 2 48 .6 2 47 .5 9 46 .9 2 48 .2 1 47 .2 1 46 .4 1 48 .4 3 48 .1 7 46 .9 7 47 .8 9 48 .3 4 ti o 2 3. 51 3. 68 3. 72 3. 64 3. 54 3. 71 3. 51 3. 65 3. 84 2. 56 2. 76 2. 57 2. 61 2. 59 2. 68 2. 58 a l 2o 3 13 .2 1 14 .2 3 13 .6 7 12 .7 3 13 .2 2 12 .5 7 13 .1 8 13 .9 9 12 .4 9 15 .4 6 15 .1 4 14 .2 1 15 .0 9 14 .9 8 14 .9 7 13 .9 9 fe 2o 3 2. 43 2. 54 1. 97 1. 84 4. 42 2. 43 4. 37 2. 67 2. 59 6. 47 7. 01 6. 79 4. 78 6. 52 4. 86 6. 82 fe o 9. 52 9. 83 11 .6 2 12 .4 4 8. 96 9. 61 8. 99 9. 84 9. 78 7. 82 7. 65 9. 13 8. 24 7. 86 8. 29 9. 15 m no 0. 21 0. 22 0. 24 0. 23 0. 23 0. 23 0. 22 0. 19 0. 23 0. 13 0. 12 0. 09 0. 07 0. 15 0. 12 0. 09 m go 5. 41 4. 76 4. 74 4. 62 3. 97 5. 79 4. 05 4. 59 5. 86 5. 88 5. 41 5. 12 5. 99 5. 91 6. 22 5. 09 ca o 9. 34 9. 38 8. 58 8. 81 7. 94 7. 64 7. 99 8. 97 7. 94 9. 02 9. 68 8. 71 9. 74 9. 11 9. 75 9. 04 n a 2 o 2. 71 2. 61 2. 41 2. 43 2. 85 3. 21 2. 81 2. 63 3. 17 3. 24 2. 94 3. 09 3. 57 3. 17 3. 41 3. 03 k 2 o 1. 29 1. 23 1. 21 1. 61 1. 99 1. 57 1. 87 1. 27 1. 46 1. 15 1. 19 1. 42 0. 67 1. 16 1. 05 1. 26 p 2 o 5 0. 37 0. 34 0. 31 0. 36 0. 41 0. 15 0. 36 0. 32 0. 19 0. 35 0. 55 0. 53 0. 13 0. 32 0. 21 0. 27 lo i 4. 23 4. 07 4. 87 4. 62 4. 52 3. 94 4. 48 3. 98 3. 87 1. 57 1. 68 0. 41 1. 48 1. 62 1. 36 1. 18 to ta l 99 .5 8 99 .7 4 99 .6 6 99 .9 99 .6 7 99 .4 7 99 .4 2 99 .0 2 99 .6 3 10 0. 86 10 0. 54 10 0. 5 10 0. 54 10 0. 36 10 0. 81 10 0. 84 m g# 0. 50 33 0. 46 33 0. 42 1 0. 39 84 0. 44 13 0. 51 79 0. 44 54 0. 45 4 0. 51 65 0. 57 27 0. 55 77 0. 49 99 0. 56 45 0. 57 27 0. 57 22 0. 49 79 n ot ic e: m g# =m g2+ /( m g2+ + fe 2+ ) g eo lo gi a c ro at ic a geologia croatica 72 / special issue24 ta bl e 3. ta ce e le m en ts (p pm ) a nd r ar e ea rt h el em en ts (p pm ) c om po si tio ns o f l uo ji an d cu iy i d ia ba se . lj -1 lj -2 lj -3 lj -4 lj -5 lj -6 lj -7 lj -8 lj -9 cy -1 cy -2 cy -3 cy -4 cy -5 cy -6 cy -7 rb 32 .9 8 34 .5 2 43 .4 8 41 .9 8 58 .6 9 39 .1 8 33 .9 7 36 .9 7 38 .6 7 30 .6 5 22 .6 1 24 .9 9 36 .9 2 29 .6 1 31 .7 6 26 .7 6 cr 12 9. 46 97 .9 6 14 6. 92 86 .9 7 49 .2 3 40 .6 8 12 6. 46 96 .5 1 41 .5 2 75 .8 6 11 3. 58 46 .3 7 15 9. 34 16 0. 32 11 6. 79 55 .6 2 n i 80 .4 9 75 .8 2 90 .5 3 77 .6 8 48 .5 7 50 .1 7 81 .7 5 73 .2 9 46 .8 3 64 .9 1 87 .2 3 63 .5 9 62 .1 9 57 .8 6 75 .6 8 52 .6 4 v 44 8. 87 57 0. 94 54 7. 61 50 3. 46 42 6. 94 58 1. 59 43 2. 89 56 8. 14 48 3. 95 38 2. 68 31 5. 69 28 7. 46 32 2. 58 16 9. 52 36 9. 32 27 9. 51 ba 34 8. 51 42 9. 03 43 6. 52 49 0. 16 59 7. 01 54 8. 26 34 9. 51 43 5. 68 51 8. 46 61 3. 92 65 7. 41 29 0. 73 83 5. 67 60 1. 39 34 6. 12 28 5. 67 th 4. 31 4. 91 4. 69 5. 08 5. 63 5. 34 4. 37 4. 89 5. 39 2. 91 3. 71 3. 16 6. 09 7. 36 3. 51 3. 12 u 0. 9 1. 01 0. 98 1. 05 1. 12 1. 05 0. 92 1. 15 1. 08 1. 25 0. 73 0. 59 1. 58 1. 58 1. 29 0. 62 ta 2. 32 2. 55 2. 54 2. 71 3. 04 3. 19 2. 36 2. 63 3. 24 3. 02 1. 75 1. 96 2. 34 3. 74 3. 04 1. 98 n b 34 .9 7 39 .1 7 39 .4 6 42 .7 9 49 .0 8 43 .5 8 33 .5 9 36 .9 4 44 .6 4 47 .5 9 28 .9 9 33 .8 6 50 .7 4 63 .8 4 45 .8 7 47 .3 6 sr 51 1. 93 63 2. 13 57 4. 91 67 7. 62 87 0. 15 81 6. 74 50 9. 67 63 4. 15 84 6. 75 45 8. 76 18 3. 74 20 5. 31 63 9. 42 36 6. 21 46 1. 85 20 3. 46 zr 21 2. 67 23 1. 59 22 6. 82 26 5. 99 29 1. 64 29 6. 81 21 6. 37 22 5. 98 29 7. 51 33 6. 54 22 3. 67 23 6. 53 36 1. 52 42 9. 76 33 7. 13 21 5. 28 h f 6. 31 6. 87 6. 81 7. 48 8. 17 8. 01 6. 28 6. 83 7. 68 8. 23 7. 39 7. 11 8. 97 9. 48 8. 94 8. 07 y 25 .4 9 27 .5 9 28 .7 3 30 .5 8 33 .2 8 31 .9 7 24 .8 3 25 .4 9 30 .5 1 28 .1 7 29 .4 6 24 .1 6 36 .5 4 39 .6 1 29 .4 6 25 .4 9 pb 4. 24 5. 62 4. 51 5. 4 5. 44 7. 07 5. 13 4. 96 6. 31 5. 23 4. 65 5. 32 4. 98 6. 17 5. 49 4. 82 cs 0. 39 0. 64 0. 63 0. 73 0. 63 0. 97 0. 86 0. 71 0. 69 0. 57 0. 82 0. 74 0. 64 0. 58 0. 61 0. 73 la 36 .1 3 39 .2 7 39 .3 7 42 .6 9 47 .5 3 47 .0 8 37 .0 1 38 .9 9 46 .9 6 44 .3 4 30 .9 7 32 .8 6 49 .5 4 60 .9 5 50 .5 4 35 .7 9 ce 76 .8 9 84 .7 5 86 .2 1 90 .4 8 10 0. 12 10 0. 18 76 .8 2 83 .9 6 99 .8 6 10 5. 42 62 .9 9 63 .7 3 11 2. 91 14 3. 67 11 7. 56 65 .8 1 pr 9. 69 10 .6 7 10 .6 8 11 .6 5 12 .8 6 12 .8 7 9. 72 10 .5 3 12 .7 9 12 .4 6 7. 93 8. 07 12 .6 1 15 .0 7 13 .0 7 7. 96 n d 39 .1 2 42 .1 6 42 .7 5 47 .3 1 51 .6 9 51 .5 8 39 .0 5 42 .0 4 50 .8 3 34 .2 5 32 .0 6 29 .7 33 .3 6 38 .2 4 33 .9 7 28 .7 9 sm 7. 42 8. 07 8. 23 8. 72 9. 35 9. 48 7. 35 8. 09 9. 53 9. 77 6. 39 7. 13 9. 96 11 .2 7 10 .6 4 6. 25 eu 2. 27 2. 56 2. 47 2. 58 2. 86 2. 96 2. 34 2. 63 2. 88 2. 76 2. 04 1. 99 2. 91 3. 24 3. 16 2. 03 g d 6. 67 7. 24 7. 62 7. 79 8. 42 8. 72 6. 59 7. 16 8. 84 8. 49 6. 06 6. 18 8. 4 9. 52 8. 42 5. 86 tb 1. 04 1. 12 1. 12 1. 16 1. 28 1. 27 1. 07 1. 15 1. 21 1. 34 1. 01 1. 12 1. 32 1. 47 1. 37 1. 21 d y 5. 87 6. 09 6. 47 6. 72 7. 18 7. 23 5. 82 6. 07 7. 22 7. 28 6. 08 6. 63 7. 3 8. 09 7. 42 5. 78 h o 1. 02 1. 12 1. 11 1. 15 1. 24 1. 22 1. 06 1. 09 1. 19 1. 3 1. 14 0. 91 1. 31 1. 43 1. 34 0. 92 er 2. 59 2. 94 3. 08 3. 18 3. 43 3. 49 2. 61 2. 97 3. 48 3. 45 3. 17 2. 62 3. 4 3. 85 3. 48 2. 58 tm 0. 36 0. 38 0. 42 0. 43 0. 49 0. 46 0. 32 0. 41 0. 45 0. 5 0. 48 0. 41 0. 48 0. 56 0. 49 0. 4 yb 2. 34 2. 53 2. 55 2. 79 2. 95 2. 85 2. 29 2. 58 2. 82 2. 95 2. 88 2. 54 2. 83 3. 22 2. 54 2. 57 lu 0. 35 0. 37 0. 43 0. 41 0. 46 0. 49 0. 34 0. 36 0. 48 0. 46 0. 45 0. 4 0. 43 0. 49 0. 43 0. 41 ∑r ee 19 1. 76 20 9. 27 21 2. 51 22 7. 06 24 9. 86 24 9. 88 19 2. 39 20 8. 03 24 8. 54 23 4. 77 16 3. 65 16 4. 29 24 6. 76 30 1. 07 25 4. 43 16 6. 36 lr ee /h re e 8. 47 43 8. 60 39 8. 32 06 8. 60 90 8. 81 77 8. 71 16 8. 57 16 8. 54 70 8. 67 46 8. 11 02 6. 69 39 6. 89 48 8. 68 83 9. 51 59 8. 98 16 7. 43 18 g eologia c roatica wang et al.: geochemistry and u-pb ages of the diabases from the luoji area, western yunnan, china: implications for the timing of the initial rifting ... 25 similar to the global mean values of crb, and they have high contents of continental crust enriched elements of cs (0.39~0.97ppm) and pb (4.24~7.07ppm), which is different from n-morb, e-morb and oib, so the studied samples belong to crb (macdonald, 2001; ma et al., 2017). the listric-shaped chondrite-normalized ree patterns of the studied samples are also similar to crb, but are different from n-morb and oib (fig. 5a). in addition, the ree diagram for the samples shows lrees enrichment with obvious hrees fractionation so that the ree curve trends are different from n-morb but similar to oib and crb (fig. 5b). however, the slight increase in ba, yb and lu, and the relative decline of sr and p are more similar to crb rather than oib. a primitive mantle-normalized spider diagram (fig. 5b) for samples shows obvious enrichment in liles (e.g., figure 5. (a) chondrite-normalized ree distribution pattern and (b) primitive mantle-normalized spider diagram for the samples (after sun and mcdonough, 1989). figure 6. plots of discrimination diagrams of (a) zr/4-nb×2-y diagram (after meschede, 1986), (b) zr-ti/100-y×3 diagram (after pearce & cann, 1973), (c) th-hf/3nb/16 diagram (after wood, 1980) and (d) zr-zr/y diagram (after pearce & norry, 1979). g eo lo gi a c ro at ic a geologia croatica 72 / special issue26 rb, ba, k) and depletion in hfses (e.g., u, nb, ce), consistent with crb. the hfses (such as ta, nb, ti, zr, hf, th and y) and hree in the basic rocks are usually not affected by metamorphism and hydrothermal alteration under the amphibolite phases (pearce et al., 1973). hfses are an effective tracer for distinguishing different tectonic settings and magma source regions (frey et al., 1978; campbell & griffiths, 1993; khoshnoodi et al., 2017). according to the tectonic-setting discriminant diagrams of wang et al. (2002) for basalts, the th/ta ratios can be used to distinguish between continent rift and oceanic settings. luoji diabase samples have lower hf/th ratios (1.40~2.82, average 1.75), higher th/ta (0.96~2.60, average 1.78) and ta/hf (0.24~0.42, average 0.35) ratios than continental within-plate basalt (hf/th=8, th/ta=1.60, ta/hf=0.1), but similar to alkaline basalt (ta/hf ratios>0.3). all analyzed geochemistry data display within-plate alkaline basalt characteristics, which are consistent with the characteristics of an intracontinental rift basalt. further, the diabase samples have characteristics of within-plate alkaline basalt and tholeiite from the discrimination diagrams (fig. 6). in generally, the combination of tholeiite and alkaline basalt series originated from intracontinental rift, initial ocean basin or an ocean island environment (lassiter & depaolo, 1997; kiss et al., 2016). furthermore, all data fall into the intracontinental and continental margin rift tholeiite-alkaline basaltic field (fig. 7). a small number of cuiyi diabase samples, which plot in the mantle plume field, may indicate that the continental rift magmatism could have been caused by an active mantle plume/an active mantle mechanism (storey & kyle, 1997). the diabases belong to high-ti tholeiite to high-k calc-alkaline series with depletion in some hfses, which is also similar to crb (mahoney et al., 1995; macdonald et al., 2001). all samples fall into the cfb field (fig. 8), which also shows that the luoji and cuiyi diabases are mainly within-plate basalts during the continental rift formation period. 5.2. magma characteristics of the rocks 5.2.1. source region in this study, hfses and rees can be good indicators for source regions. in fig. 9 and fig. 10a, the samples all originated from a low-degree partial melting of enriched mantle with the participation of a small quantity of crust and/or continental margin material, which is highly consistent with crb (campbell & griffiths, 1993; lassiter & depaolo, 1997). this suggests that the magma source region may have a slight crustal contamination (peccerillo & taylor, 1976), and all samples fall into the crb field in the la/nb vs. la/ba discrimination diagrams (fig. 10b), which also indicates a slight crustal contamination (cui et al., 2015). high ce/yb ratios of the diabases (32.58~33.78) indicate the low-degree of melting and garnets as the main residual phases, and the samples also plot in the garnet stable field (fig. 11a, cui et al., 2015; kiss et al., 2016). in the la/sm vs. sm/yb diagram (fig. 12a), the samples all plot on the upper part of the primitive mantle melting curve with a slight deviation from the melting of the garnet lherzolite field, which may be caused by the low-degree melting of the source region and a certain degree of upper crustal contamination (campbell & griffiths, 1993; mafigure 7. tectonic setting discrimination diagrams. (a) ta/hf vs. th/hf diagram (after wang et al., 2001); (b) nb/zr vs. th/zr diagram (after sun et al., 2003); (c) nb/zr vs. la/zr diagram (after wu et al., 2003). figure 8. classification diagram of ti/1000 vs. v for basaltic magma (after shervais, 1982). g eologia c roatica wang et al.: geochemistry and u-pb ages of the diabases from the luoji area, western yunnan, china: implications for the timing of the initial rifting ... 27 honey et al., 1995; jung & masberg, 1998). further, the samples plot near the primary garnet lherzolite field and the distribution of the luoji diabase samples is relatively concentrated (fig. 12b), which indicate the samples may be the products of partial melting of 2%~3% garnet lherzolite phases (khoshnoodi et al., 2017; ma et al., 2017). although the distribution of the cuiyi diabase samples is relatively wide (fig. 12b), it is still in the vicinity of the primary garnet lherzolite field. the reason why the ce/y ratios of the cuiyi diabase fluctuates greatly may be caused by crustal contamination. combined with the hf vs. hf/yb diagram (fig. 11b), it shows that diabases originated in a deep position and were formed by decompression melting of the mantle with a low degree of partial melting and strong differentiation of lree and hree (especially in the cuiyi diabase). there is an obvious negative p anomaly in all samples without extreme deficiency in the chondrite-normalized ree distribution pattern (fig. 5a), which can be combined with three possible reasons for negative p anomalies (campbell & griffiths, 1993; kiss et al., 2016): a source region deficiency in p; residual apatites in the source region; fractional crystallization of negative p minerals, where apatites remained in the source region resulting in less p in samples than in the global crb-type samples. figure 9. source discrimination diagrams. (a) zr/y vs. nb/y diagram (after saunders et al., 1997); (b) nb/yb vs. th/yb diagram (after pearce, 1982); (c) la vs. la/nb diagram (after li, 1993); (d) nb vs. nb/th diagram (after li, 1993). figure 10. (a) ta/yb vs. th/yb diagram (after pearce, 1982); (b) la/nb vs. la/ba diagram for crustal contamination (after miller et al., 1999). g eo lo gi a c ro at ic a geologia croatica 72 / special issue28 5.2.2. assimilation and contamination the mg# values of the samples vary from 0.40 to 0.57 and are significantly lower than those of the primary magma (0.68~0.75), which indicates that the rocks had experienced a certain degree of fractional crystallization (frey et al., 1978). low contents of mgo and feo in the samples may indicate the fractional crystallization of augite and diopside during the process of magmatic evolution, or the formation of a basic-ultrabasic complex (cumulates), which results in a large reduction of mg (hawkesworth et al., 1993; jung & masberg, 1998; khoshnoodi et al., 2017), and then the magmatic differentiation formed the geochemical characteristics of low mg in the diabases. according to the compatibility of elements in different minerals, the abundance of elements will change with crystallization. the ratios of elements sensitive to assimilation and contamination are an indicator of assimilation and contamination because of the compositional differences between the crust and the mantle (cambell & griffiths, 1993; macdonald et al, 2001). the luoji and cuiyi diabases show an obvious positive correlation in the th/nb vs. ce/nb and ta/yb vs. th/yb diagrams (fig. 13a and 13b), indicating that there is a certain assimilation and contamination in the samples (hawkesworth et al., 1993; kiss et al., 2016). the nb/u and ta/u ratios of the samples are 32.12~76.39 (average 42.10) and 1.48~3.32 (average 2.59), respectively, which are lower than the global relative homogeneous values of morb and oib (nb/u≈47 and ta/u≈2.7). the ta/la ratios (0.05~0.07, average 0.062) are slightly higher than the standard value (0.06) of the original mantle (liang et al., 2018), which indicate that the diabases are obviously contaminated by the crust or the source region. it is generally believed that the crustal material has low nb and high th characteristics (wang et al., 2018). the positive correlation between th and nb (fig. 13c), a slight negative correlation between la/yb and nb/ta (fig. 13d) and a slight negative nb anomaly in the diabases, together indicate that the samples have been affected by crustal contamination (jung & masberg, 1998). similarly, the depletion in lile of sr in the primitive mantle-normalized spider diagram (fig. 5b) may be mainly due to the contamination by crustal materials (szabó et al., 2016; kiss et al., 2016). variation of mantle element contents and nb/la ratios are an obvious indicator of the process of assimilation, contamination and fractional crystallization (taylor & mclennan et al., 1995). there is a positive correlation between mg# and cr, ni, v, zr, sr and nb/la (fig. 14), which shows that the fractional crystallization of the diabases are affected by assimilation and contamination (frey et al., 1978; campbell & griffiths, 1993; hawkesworth et al., 1993). meanwhile, the sio2 vs. nb/la diagram (fig. 15a) indicates that the evolutionary process of the diabases is dominated by fractional crystallization, and figure 11. (a) the chondrite-normalized (la/sm)n and (tb/yb)n diagram (after wang et al., 2001; wang et al., 2002); (b) hf-hf/yb diagram (after weaver, 1987). figure 12. (a) la/sm vs. sm/yb diagram (after lassiter & depaolo, 1997); (b) zr/nb vs. ce/y diagram (after gao et al., 2009). g eologia c roatica wang et al.: geochemistry and u-pb ages of the diabases from the luoji area, western yunnan, china: implications for the timing of the initial rifting ... 29 there are signs of contemporaneous assimilation and contamination. in the cao vs. cao/al2o3 diagram (fig. 15b) the two groups of samples are consistent with a large consumption of mg in the magma caused by the fractional crystallization with clinopyroxe ne resulting in the low mgo content in the samples. the relative enrichments in rb, ba and th also indicate that magmatic migration has undergone crustal contamination (cui et al., 2015; kiss et al., 2016). previous studies (macdonald et al., 2001; ma et al., 2017) have shown that strong depletion in sr of some highmg basalts may be affected by contamination or alteration. therefigure 13. trace element discrimination diagrams for assimilation and contamination. figure 14. plots of selected trace elements with mg# for discrimination contamination. g eo lo gi a c ro at ic a geologia croatica 72 / special issue30 fore, negative sr anomalies and negligible negative eu anomalies in the samples are not caused by plagioclase fractionation. combined with the above analysis, the geochemical characteristics of major and trace elements in the samples may reflect assimilation and contamination by crustal rocks during the emplacement of the crb magma. 5.3 geological significances the timing of the opening of the ganzi-litang ocean basin may have been in the early carboniferous, subduction in the early triassic and closure in the terminal period of the late triassic (wang et al., 2018). combined with the recent study, it can be concluded that the study area has experienced three tectonic evolutionary stages during the permian to triassic period, i.e., an intracontinental rift basin stage during the early to middle permian, initial ocean basin stage during the terminal permian and oceanic crust subduction stage during the late permian to early triassic (hou et al., 2001; liang et al., 2018). however, the opening time of the ganzi-litang ocean basin is controversial due to the uncertainty of the stretching time and the complexity of the rock exposures. hence, the accurate development timing especially of the intracontinental rift stage of initial ganzi-litang ocean has never been reported. all the collected data including the zircon u-pb ages of morb and oib, is disadvantageous and incomplete for determining the timing of the opening and the evolutionary processes for the ganzi-litang ocean without the crb. so a large number of diabase samples were sought in this study to find out the crb samples. finally, the luoji and cuiyi diabase samples were discovered and have typical crb characteristics discovered through geochemical data analysis. this indicates that the crystallization age of the luoji diabase can accurately define the timing of the intracontinental rift stage of the ganzi-litang ocean and is also essential for determining the precise timing of the opening of the ganzi-litang ocean. in view of the zircon structures and th/u ratios (0.11~5.80), zircons from the luoji diabase indicate they are of magmatic origin. a concordia age of the oldest 21 analyses is 1907ma, which may represent a mantle-derived magmatic event in the western margin of the yangtze block in the late palaeoproterozoic (zhao et al., 2010). a set of data in 1245ma~1028ma may represent the grenvillian orogeny and related magmatic events during the mesoproterozoic period (li et al., 2002). another set of data in 901ma~757ma may represent a magmatic event with a span of about 260ma (1000ma~740ma) in the western margin of the yangtze in the neoproterozoic (sun et al., 2009). these zircons would be inherited zircons. for the youngest set of data (303ma~291ma), the zircon u-pb age of the luoji samples is 293.4±5.4ma (early permian), which should represent the crystallization age of the rock. some zircon u-pb ages have been obtained in the southern part of the ganzi-litang suture zone. for example, 341.6±4.9ma of mid-ocean ridge low-k tholeiite series gabbro in the ophiolite mélange belt, the baihanchang area, 272.8±1.2ma for a gabbro-diabase in the tuguan village and 221.24±0.93ma of the ofb (floor-ocean ridge basalt)-morb in tangyang country. the age of the hongshan-shudu ophiolites determined by sm-nd isotope is 230ma (hou et al., 2001; ybgmrrgst, 2003; liang et al., 2018). in the middle part of the ganzi-litang suture zone, an la-mc-icp-ms zircon u-pb age of the pillow basalt in the charichadong area is 271±10 ma. in terms of biostratigraphy, the early triassic radiolarians were developed in the litang wenquan and early-late triassic radiolarians were developed in the yazui pasture xigou-litang wenquan. in the northern part of the ganzi-litang suture zone, the zircon u-pb age of the gabbro in the n-morb ophiolite is 292±4ma. in terms of biostratigraphy, the early carboniferous radiolarians in siliceous rocks are developed in the zhuqing area of northern ganzi, in addition, early carboniferous, middle permian, middle triassic and late triassic radiolarian siliceous rocks occur in the yushu xiewu, dege country zhuqinglangduo-sanchahe and zhuqing village-jike (hou et al., 2001). based on the zircon u-pb ages, the luoji and cuiyi diabases may belong to the products of the intracontinental rift-initial ocean basin stage. combining the data of zircon geochronology and biostratigraphic geochronology from north to south, suggests that there is a trend towards a younging for the timing of the opening of the ganzi-litang ocean from the north to the south, which may be related to the evolution of the ganzi-litang ocean. the u-pb age of the intracontinental rift-type diabase in the study area is 293.4±5.4ma, which is analogous with the zircon age of the n-morb ophiolite in the ganzi area (liang et al., 2018). this also shows that the opening of the ganzi-litang ocean in the southern section may have lagged behind that in the northern section. therefore, the comprehensive analysis shows that the study area started to enter into an intracontinental rift stage of initializing the ganzi-litang ocean at 293.4±5.4ma (early permian) and formed an enriched mantle parent magma with crb affinity. then the parent magma formed the luoji diabase in the intracontinental rift environment through crystallization and differentiation, assimilation and contamination and ascending emplacement. figure 15. discrimination diagrams for fractional crystallization and assimilation-contamination. (a) sio2 vs. nb/la diagram; (b) cao vs. cao/al2o3 diagram. g eologia c roatica wang et al.: geochemistry and u-pb ages of the diabases from the luoji area, western yunnan, china: implications for the timing of the initial rifting ... 31 6. conclusion 1. the luoji and cuiyi diabases are high-k alkaline to tholeiite with low si, high ti, k, fe and zr characteristics, which are similar to crb but different from n-morb and oib. 2. the diabases were formed by low-degree partial melting of an enriched mantle source consisting of garnet lherzolite with slight crustal contamination. they were formed in an intracontinental rift basalt setting, related to mantle plume activity during the initial opening stage of the ganzi-litang ocean. 3. la-icp-ms zircon u-pb data show that the luoji diabase was emplaced at 293.4±5.4ma, indicating the initial opening of the ganzi-litang ocean occurred during the very early permian. references campbell, i.h. & griffiths, r.w. (1993): the evolution of the mantle’s chemical structure.– lithos, 30, 389–399. doi: 10.1016/0024-4937(93)90047-g cui, x.z., jiang, x.s., wang, j., wang, x.c., zhou, j.w., deng, q., liao, s.y., wu, h., jiang, z.f. & wei, y.n. (2015): mid-neoproterozoic diabase dykes from xide in the western yangtze block, south china: new evidence for continental rifting related to the breakup of rodinia supercontinent.– precambrian research, 268, 339–356. doi: 10.1016/j.precamres.2015.07.017 frey, f.a., green, d.h. & roy, s.d. (1978): intergrated models of basalts petrogenesis: a study of quartz tholeiites to olivine melitites from southeastern australia utilizing geochemical and experimental petrological data.– journal of petrology, 19, 463–513. gao, r., xiao, l., wang, g.c., cao, s.z., luo, y.j., yuan, j. & he, q. (2009): geochemistry, petrogenesis and significance of late paleozoic basalts in kokshal district, south tianshan mountains.– journal of mineralogy and petrology, 29/2, 96–107 (in chinese with abstract). greenough, j.d. & mcdivitt, j.a. (2018): earth’s evolving subcontinental lithospheric mantle: inferences from lip continental food basalt geochemistry.– international journal of earth sciences, 107, 787–810. hawkesworth, c.j., gallagher, k., hergt, j.m. & mcdermott, f. (1993): mantle and slab contributions in arc magmas.– annual review of earth and planetary sciences, 211/1, 175–204. doi: 10.1146/annurev.ea.21.050193.001135 hou, z.q., qu, x.m., zhou, j.r., yang, y.q., huang, d.h, lv, q.f., tang, s.h., yu, l.j., wang, h.p. & zhao, j.h. (2001): collision-orogenic processes of the yidun arc in the sanjiang region: record of granites.– acta geologica sinica, 75(04), 484–497 (in chinese with english abstract). hu, z.c., liu, y.s., chen, l., zhou, l., li, m., zong, k.q., zhua, l.y. & gao, s. (2011): contrasting matrix induced elemental fractionation in nist srm and rock glasses during laser ablation icp-ms analysis at high spatial resolution.– journal of analytical atomic spectrometry, 26/2, 425–430. doi: 10.1039/ c0ja00145g irvine, t.n. & baragar, w.r.a. (1971): a guide to the chemical classification of the common volcanic rocks.– canadian journal of earth sciences, 8/5, 523–548. doi: 10.1139/e71-055 jackson, s.e., pearson, n.j., griffin, w.l. & belousova, e.a. (2004): the application of laser ablation-inductively coupled plasma-mass spectrometry to in situ u–pb zircon geochronology.– chemical geology, 211, 47–69. jung, s. & masberg, p. (1998): major-and trace-element systematics and isotope geochemistry of cenozoic mafic volcanic rocks from the vogelsberg (central germany): constraints on the origin of continental alkaline and tholeiitic basalts and their mantle sources.– journal of volcanology and geothermal research, 86/1, 151–177. khoshnoodi, k., behzadi, m., maragheh & g-m., yazdi, m. (2017): alkali metasomatism and th-ree mineralization in the choghart deposit, bafq district, central iran.– geologia croatica, 70/1, 53–69. doi: 10.4154/gc.2017.03 kiss, g.b., molnár, f. & palinkaš, l.a., (2016): hydrothermal processes related to some triassic and jurassic submarine basaltic complexes in northeastern hungary, the dinarides and hellenides.– geologia croatica, 69/1, 39–64. doi:10.4154/gc.2016.04 lassiter, j.c., & depaolo, d.j. (1997): plume/lithosphere interaction in the generation of continental and oceanic flood basalts: chemical and isotopic constraints.– geophysical monograph series, 100, 335–355. doi: 10.1029/ gm100p0335 li, s.g. (1993): ba-nb-th-la diagrams used to identify tectonic environments of ophiolite.– acta petrologica sinca, 9/2, 146–157 (in chinese with abstract). li, z.x., li, x.h., zhou, h.w. & kinny, p.d. (2002): grenvillian continental collision in south china: new shrimp u-pb zircon result and implication for the configuration of rodinia.– geology, 30/2, 163–166. doi: 10.1130/0091-7613(2002)030%3c0 163:gccisc%3e2.0.co;2 liang, q., yang, w.x., yan, d.p., michael, l.w., qiu, j.t., gao, t., dong, j.m., zhang, l.l. & wang, f.y. (2018): geochronology of early mesozoic diabase units in southwestern china: metallogenic and tectonic implications.– geol. mag., 1–16. liu, h., wang, g.c., cao, k., meng, y.n., wang, a. & zhang, k.x. (2010): the detrital zircon fission–track ages constraint to tectonic processes in west kunlun and adjacent regions.– earth science frontiers, 17/3, 64–78 (in chinese with english abstract). ludwig, k.r. (2012): user’s manual for isoplot/ex rev. 3.75 a geochronological toolkit for microsoft excel. berkeley geochronology center, special publication no. 5, 70–86. ma, x.x., dong, c.w., zhou, c., lv, q., gu, h.y. & wu, w.w. (2017): the neoproterozoic continental rift magmatism of the eastern jiangnan orogen: new evidence from the mafic sheets in northern zhejiang province, south china.– international geology review, 59/7, 829–844. doi: 10.1080/00206814.2016.1232180 macdonald, r., rogers, n.w., fitton, j.g., black, s. & smith, m. (2001): plume–lithosphere interactions in the generation of the basalts of the kenya rift, east africa.– journal of petrology, 42, 877–900. mahoney, j.j., jones, w.b., frey, f.a., salters, v.j.m., pyle, d.g. & davies, h.l. (1995): geochemical characteristics of lavas from broken ridge, the naturaliste plateau and southernmost kerguelen plateau: cretaceous plateau volcanism in the southeast indian ocean.– chemical geology, 12, 315–345. doi: 10.1016/00092541(94)00144-w maniar, p.d. & piccoli, p.m. (1989): tectionic discrimination in of granitoids.– geological society of america bulletin, 101, 635–643. meschede, m. (1986): a method of discriminating between different types of mid-ocean ridge basalts and continental tholeiites with the nb-zr-y diagram.– chemical geology, 56, 207–218. middlemost, e.a.k. (1994): naming materials in the magma/igneous rock system.– earth–science reviews, 37(3–4), 215–224. doi: 10.1016/0012-8252(94)90029-9 miller, c., schuster, r., klötzli, u., frank, w. & purtscheller, f. (1999): post-collisional potassic and ultrapotassic magmatism in sw tibet: geochemical and sr-nd-pb-o isotopic constraints for mantle source characteristics and petrogenesis.– journal of petrology, 40/9, 1399–1424. doi: 10.1093/petroj/40.9.1399 pearce, j.a. (1982): trace element characteristics of lavas from destructive plate boundaries. thorps r s. andesites. new york: john wiley and sons, 525–548. pearce, j.a. & cann, j.r. (1973): tectonic setting of basic volcanic rocks determined using trace element analyses.– earth and planetary science letters, 19, 290–300. doi: 10.1016/0012-821x(73)90129-5 pearce, j.a., & norry, m.j. (1979): petrogenetic implications of ti, zr, y, and nb variations in volcanic rocks.– contributions to mineralogy and petrology, 69/1, 33– 47. doi: 10.1007/bf00375192 peccerillo, a. & taylor, s. (1976): geochemistry of eocene calc-alkaline volcanic rocks from the kastamonu area, northern turkey.– contributions to mineralogy and petrology, 58/1, 63–81. doi: 10.1007/bf00384745 raczek, i., stoll, b., hofmann, a.w. & jochum, k.p. (2010): high-precision trace element data for the usgs reference materials bcr-1, bcr-2, bhvo-1, bhvo-2, agv-1, agv-2, dts-1, dts-2, gsp-1 and gsp-2 by id-tims and micssms.– geostandards & geoanalytical research, 25/1, 77–86. doi: 10.1111/j.1751-908x.2001.tb00789.x saunders, a.d., fitton, j.g., kerr, a.c., norry, m.j. & kent, r.w. (1997): the north atlantic igneous province.– geophysical monograph series, 100, 45–94. doi: 10.1029/gm100p0045 shervais, j.w. (1982): ti-v plots and the petrogenesis of modern and ophiolitic lavas.– earth planet. sci. lett., 59, 101–118. doi: 10.1016/0012-821x(82)90120-0 storey, b.c. & kyle, p.r. (1997): an active mantle mechanism for gondwana breakup.– south african journal of geology, 100/4, 283–290. sun, s.s. & mcdonough, w. (1989): chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes.– geological society, london, special publications, 42/1, 313–345. doi: 10.1144/gsl.sp.1989.042.01.19 sun, s.q., wang, y.l. & zhang, c.j. (2003): discrimination of the tectonic setting of basalts by th, nb and zr.– geological review, 49/1, 40–47 (in chinese with abstract). sun, w.h., zhou, m.f., gao, j.f., yang, y.h., zhao, x.f. & zhao, j.h. (2009): detrital zircon u-pb geochronological and lu-hf isotopic constraints on the precambrian magmatic and crustal evolution of the western yangtze block, sw china.– precambrian research, 172, 99–126. doi: 10.1016/j.precamres.2009.03.010 szabó, b., schubert, f., tóth, t. m., steinbach, g. (2016): palaeofluid evolution in a fractured basalt hosted reservoir in the üllés-ruzsa-bordány area, southern sector of the pannonian basin.– geologia croatica, 69/3, 281–293. doi: 10.4154/ gc.2016.25 taylor, s.r. & mclennan, s.m. (1995): the geochemical evolution of the continental crust. – review of geophys., 33/2, 241–265. doi: 10.1029/95rg00262 wang, c., liu, h., deng, j.h., liu, x.f., zhao, f.f., wang, c. & tian, x. (2018): isotope geochronologic and geochemical constraints on the magmatic g eo lo gi a c ro at ic a geologia croatica 72 / special issue32 associations of the collisional orogenic zone in the west kunlun orogen, china.– acta geologica sinica (english edition), 92/2, 482–498. wang, k., plank, t., walker, j.d. & smith, e.i. (2002): a mantle melting profile across the basin and range, sw usa.– journal of geophysical research, 107(b1), 2017. doi: 10.1029/2001jb000209 wang, y.l., zhang, c.j & xiu, s.z. (2001): th/hf-ta/hf identification of tectonic srtting of basalts.– acta petrologica sinica, 17/3, 413–421 (in chinese with english abstract). weaver, b.l. (1991): the origin of ocean island basalt end-member compositions: trace element and isotopic constraints.– earth and planetary science letters, 104/2, 381–397. doi: 10.1016/0012-821x(91)90217-6 weaver, s.d. & johnson, r.w. (1987): in tectonic controls on magma chemistry. elsevier, amsterdam, 161–176. wedenbeck, m., alle, p., corfu, f., griffin, w.l., meer, m., oberli, f., vonquadt, a., roddick, j.c. & spegel, w. (1995): three natural zircon standards for u-th-pb, lu-hf, trace element and ree analyse.– geostandards and geoanalytical research, 19/1, 1–23. doi: 10.1111/j.1751-908x.1995.tb00147.x wood, d.a. (1980): the application of a th-hf-ta diagram to problems of tectonomagmatic classification and to establishing the nature of crustal contamination of basaltic lavas of the british tertiary volcanic province.– earth and planetary science letters, 50, 11–30. wu, l.n., wang, z.c. & wang, y.l. (2003): on the application of la, nb and zr in identifying the tectonic settings.– journal of east china geological institute, 26/4, 343–348. xie, x.j., yan, m.c. & wang, c.s. (1989): geochemical standard reference samples gsd 9–12, gss 1–8 and gsr 1–6.– geostandards and geoanalytical research, 13/1, 83–179. doi: 10.1111/j.1751-908x.1989.tb00469.x ybgmrrgst, yuannan bureau of geology and mineral resources of regional geological survey team. (2003): 1: 250000 zhongdian county geological survey report (in chinese). zhao, x.f., zhou, m.f., li, j.w., sun, m.,gao, j.f., sun, w.h. & yang, j.h. (2010): late paleoproterozoic to early mesoproterozoic dongchuan group in yunnan, sw china: implications for tectonic evolution of the yangtze block.– precambrian research, 182(1/2), 57–69. doi: 10.1016/j.precamres.2010.06.021 zhou, x., li, z.h., gerya, t.v., stern, r.j., xu, z.q & zhang, j.j. (2018): subduction initiation dynamics along a transform fault control trench curvature and ophiolite ages.– the geological society of america, 46/7, 607–610. doi: 10.1130/ g40154.1 ab stra ct the croatian offshore hydrocarbon province is highly under-explored. from a total number of 128 exploration wells, 96 were drilled in the northern adriatic sea, 27 in the central adriatic sea and only 5 in the southern adriatic sea. most of exploration wells were drilled to test the pliocene shallow sandstone biogenic gas play, which has been in production since the end of the twentieth century. however, the deep mesozoic oil plays are still heavily under-explored. by interpreting regional studies, offshore well datasets and 2d seismic lines acquired by spectrum in 2013, this study identified two new interesting explorative plays: structural karst play (triassic/jurassic); slope calciturbidites play (cretaceous/eocene). 2d petroleum system modeling was performed along a representative interpreted seismic section to define the potential and the exploration risk of the two plays. the results show that all the critical elements for a working petroleum system are present for both plays. several fluid-saturated traps are present in the cretaceous and jurassic reservoirs with an indicative total depth between 3500 and 5500 m and in water depth from 500 to 1200 m. for the structural karst play the main uncertainties are related to the quality and efficiency of the reservoir, while for the slope calciturbidites play the main uncertainty is related to the sealing efficiency. keywords: croatian offshore, deep target southern adriatic sea, petroleum system modeling, mesozoic carbonatic traps  exploring the potential of deep targets in the south adriatic sea: insight from 2d basin modeling of the croatian offshore  nicoletta mazzuca1, alessandro bruni2 and thorsten joppen3 1 enel s.p.a, viale regina margherita 137, 00198, rome, italy; (nicoletta.mazzuca@enel.com) 2 upstream gas division, enel trade s.p.a, via arno 42, 00198, rome, italy 3 schlumberger information solutions, ritterstr. 23, 52072 aachen, germany doi: 104154/gc.2015.18 quisition of a good quality seismic dataset. on the croatian side, high quality seismic data was only obtained in 2013, when spectrum acquired 14,700 km of long streamer 2d seismic lines (yellow lines in fig. 1). this seismic dataset provided the opportunity to reconstruct a geological crosssection along the south croatian offshore and to interpret potential triassic and jurassic source rock systems as well as multiple carbonate platforms where it is possible to distinguish changes in seismic facies and thickness from the triassic to the cretaceous (fig. 2). the aim of this study is to evaluate the efficiency of the thermogenic petroleum systems for the two newly identified and under-explored plays in the southern croatian offshore (fig. 2). the structural karst play (triassic/jurassic), formed by antiform traps in the carbonate karst of the adriatic carbon1. introduction hydrocarbon exploration in the croatian offshore started with the jadran-1 well, drilled in 1970. the first success came three years later when the ivana gas field was discovered by the jadran-6 well. this initial discovery was in the pliocene shallow clastic biogenic gas play in the northern adriatic sea and was followed by the discovery of additional gas fields that are still in production. the hunt for oil in the central and southern adriatic-ionian basin, began later. the focus was the eocene and late cretaceous carbonate platform potential oil plays in the shelf area (bejdic, 2012), but a few wells encountered oil shows (e.g. melita-1, vlasta-1). as a consequence this area remained under-explored. in contrast, the rovesti and giove wells in the italian apulian platform margin led to interesting oil discoveries (fig. 1). this exploration success was followed by the acgeologia croaticageologia croatica geologia croatica 68/3 237–246 12 figs. zagreb 2015 geologia croatica 68/3geologia croatica 238 is characterized by deposition of bituminous limestone interbedded with dolomite formations in syn-rift grabens. in the middle liassic, the main tethyan rifting phase caused the break-up of the previously continuous carbonate platform (vlahovic et al., 2005). as a consequence, two main pelagic domains were generated, the umbria-marche and south adriatic basins with limestone to siliciclastic sequences deposited from the middle jurassic until the paleogene (cati et al., 1987). two different carbonate platforms remained separated: the dalmatian-adriatic to the east-northeast and the apulian to the southwest. southwest verging dinaric compression and thrust ing, similar to that affecting the ionian basin to the south, affected the dalma tian-adriatic platform, developing a foredeep in the late eocene and oligo-miocene times. in a similar way, the east-vergent apulian thrusting formed a foredeep during the plio-pleistocene (wrigley et al., 2014). successive deltaic sequences commenced in the paleocene until the present day, prograding from the po valley of italy and the neretva river of croatia, with little localized sediment supply from demolition of the dinaric thrust belt. the only exception is the evaporitic deposition during the messinian. the effect of the messinian salinity crisis was the generation of a clear and easily recognizable unconformity separating the oligo-miocene from the pliopleistocene sequence. this geological evolution favoured the development of a platform carbonate succession alternating with basin deposits, constituting the elements for efficient deep petroleum systems (fig. 3). bituminous limestone rocks deposited in the upper triassic and early jurassic syn-rift grabens can have high source rock potential as indicated and supported by italian analogs. ate platform (adcp) (vlahovic et al., 2005), was created as paleo-highs from the triassic to the lower jurassic and moved during the tertiary due to transpression. the traps could be charged by hydrocarbons from upper triassic source rocks and sealed by deposits from the lower jurassic and middle cretaceous (fucoidi fm.); the slope calciturbidites play consists of stratigraphic traps formed as a series of carbonate fans extended basinward and related to partial disintegration of the upper mesozoic adcp during the end of the cretaceous-eocene period (vlahovic et al., 2005). the traps could be charged by upper triassic and lower jurassic source rocks and sealed by tertiary deposits. 2. geological setting of the croatian adriatic offshore the regional geology and tectonic history of the croatian adriatic basin is well described in the literature (casero et al., 2012; grandic et al., 2013; shiner et al., 2013). the adriatic basin developed on the ‘adria microplate’, on the stable western margin of gondwana’s neo-tethys, which began to rift and subside in the permo-triassic. the permian to anisian sequences show siliciclastic beds or limestones and dolomites, interbedded by salt and gypsum deposits. the permian is correlated to wells and outcrops of onshore croatia (grandic et al., 2004). in the carniannorian period, the main lithofacies in the periadriatic region were the dolomia principale/burano formations from the extensive tidal zone to the evaporitic platform. the burano evaporites (mainly salt and anhydrite) are present in the central and southern sectors of the adriatic sea (mattavelli et al., 1991). the end of the triassic and the lower jurassic figure 1: location map and available data set. mazzuca et al.: exploring the potential of deep targets in the south adriatic sea: insight from 2d basin modeling of the croatian offshore geologia croatica 239 the stratigraphic column representing the study area and its petroleum system elements was reconstructed from the regional geological setting, the interpretation of croatian wells implemented with italian well information and the interpretation of new seismic data acquired by spectrum (fig. 3). the identification of triassic evaporites has a big impact on the mesozoic petroleum system. within the adriatic margin the evaporitic deposits are predominantly anhydritic to the west and a mix of anhydrite and halite to the east (grandic et al., 1997). these evaporitic sequences often represent the detachment surface of major thrusts, emphasizing the “structural ejection” (development of high structure) of both compressive and strike-slip tectonics. the apulian platform margin was remarkably stable remaining almost stationary from the triassic to the late cretaceous (casero & bigi, 2013). this stability is not proven for the croatian carbonate platform edge, where the eastern platform was deposited over mobile halite (casero & bigi, 2013). salt bounded car bonate rafts and complex margins conditions can justify porosity enhancement via karstification, remobilization of carbonate and reefal build ups (wrigley et al., 2014). 3. model methodology basin and petroleum systems modeling is an integrated multidisciplinary approach to track the evolution of a basin through time as it fills with fluids and sediments that may eventually generate or contain hydrocarbons. the modeling process consists of two main stages: model building and forward modeling. model building involves building a structural model and identifying the chronology of deposition and physical properties of each layer. forward modeling performs calculations on the model to simulate sediment burial, pressure and temperature changes, kerogen maturation and hydrocarbon expulsion, migration and accumulation. the calibration phase com pares simulation results with independent measurements (e.g. well data) to enable refinement of the model (al-hajeri et al, 2009). the output model helps understanding of expulsion timing and potential migration paths existing in the system as well as the exploration risks. these processes may be examined at several levels, and complexity typically increases with spatial dimensionality. considering the restricted available dataset in the area of interest (fig. 1), 2d modeling along the key cross section was performed using, the petromod 2d (2014) software. petromod 2d solves deterministic computations based on the discrete numerical representation of layers subdivided into grid cells with uniform properties. the software simulate physical processes that act on each cell, starting with initial conditions and progressing by selected time increments to the present day. fi gu re 2 : 2 d re pr es en ta tiv e in te rp re te d se is m ic se ct io n co ns id er ed in th e pr es en t s tu dy . geologia croatica 68/3geologia croatica 240 3.1. model building the depth-converted horizons coming from the key interpreted seismic line were used as input for building the 2d model. the seismic line is located in the south adriatic sea and extends from the croatian coastline to the italy-croatia offshore border (fig. 4). the long streamer used during the new 2d seismic survey, revealed interesting deep reflectors that probably belong to triassic formations. these reflectors are the first acoustic impedance contrasts below the mesozoic platform carbonates and may indeed represent low-velocity bituminous limestone deposits (fig. 4). oligo-miocene and plio-pleistocene stratigraphic plays onlapping deeper structures are also interpreted. the messinian unit is a characteristically strong reflector and may represent a clastic play south of the gargano arch. the interpretation resulted from examination of regional geological studies, 2d seismic sections and well data on the italian and croatian side. the main reflectors coming from the seismic interpretation are: the sea bed, top of the miocene, top of the oligocene, top of the eocene, top of the fucoidi marls (l. cretaceous), top of the lias (jurassic) and an horizon within the triassic. based on the wells stratigraphy and regional thickness maps, several other units have been interpreted: near top cretaceous, top lias source rock, near top mid-lias (massiccio equivalent) and near top triassic (fig. 4). for the deepest reflectors, no well calibration was available. as the interpreted time horizons and the depth conversions were done on an incomplete dataset, the depth model is not accurate. for modeling purposes, 4 main horizons were added to the model on the basis of the italian wells (fig. 5): the base fucoidi fm. (30 m below the interpreted top); the base liassic source rock (50 m below the interpreted top); the base trias source rock (50 m below the interpreted top); the basement (about 1500 m below the base of the trias source rock). the facies model with the associated physical properties for the main petroleum system elements (sources, reservoirs and seals) was built on the basis of the evolution of the sedimentary sequence of the dinarides, from the paleozoic-triassic clastic-evaporite sediments through the mesozoic carbonate-anhydrite sequence to the tertiary clastics (fig. 6). the main reservoirs were characterized as: • triassic (rhaetian), dolomite (organic lean, sandy); • jurassic (lias), dolomite (organic rich 50% and lean 50%); figure 3: reconstructed stratigraphic column with the main petroleum system elements. mazzuca et al.: exploring the potential of deep targets in the south adriatic sea: insight from 2d basin modeling of the croatian offshore geologia croatica 241 • jurassic (malm), dolomite 50% and ooid 50%; • cretaceous, limestone (ooid grainstone); • eocene, limestone (ooid grainstone). the seals were considered to be the tertiary deposits (marl 50% and conglomerates 50%), the upper cretaceous fucoidi (marl) and the source rock intervals. the upper triassic source rock was the bituminous lime stone inside burano formation (andrè & doulcet, 1991). the second source was more speculative and mainly based on liassic italian analogous to the emma limestone formation, documented for the grifone-1 well (mattavelli et al., 1993; casero, 2004). the geochemical parameters (total organic carbontoc, kinetics and hydrogen index–hi) used for the source rocks were (pepper&corvi,1995): • trias source: toc 1,7%, hi 700, kinetics type ii s; • lias source: toc 2%, hi 700, kinetics type ii s. bottom hole temperature (bht) data from the logs of about 10 wells were collected, corrected for equilibrium temperature and interpreted to gain understanding of the trend of the geothermal gradient. the horner method was used. it plots the measured temperature (at a given depth) from each of several logging runs, against log(t/(t+t)). the parameter t represents the length of time that the borehole was subjected to the cooling effects of the fluid, and t represents the time after circulation that the borehole has had to partially reheat. the best fit straight line results from the plot is extrapolated to cut the temperature axis where logt/(t+t) equals zero, reflecting the true formation temperature at that particular depth. we have assumed mean surface temperature to be 7˚c. figure 4: interpreted horizons used as input for the 2d basin modeling. figure 5: seismic horizons added for 2d basin modeling purpose. geologia croatica 68/3geologia croatica 242 the geothermal gradient of the study area varies from 10°c/km to 30°c/km and averages about 17°c/km (fig. 7). 3.2. forward modeling to run the simulation, three important boundary conditions were defined: 1. paleo water depth (pwd); 2. sediment water interface temperature (swit); 3. paleo heat flow (hf). two main trends were used as input to simulate the paleo-environment that defines the pwd and swit: one to model the geometry of a stable shelf through geological time and the second to simulate the basin conditions. for the paleo hf history only one trend was used to simulate the effect of the triassic rifting event and the subsequent phase of thermal subsidence (cooling). vitrinite data for only one well was useful for calibrating the reconstructed heat flow history. two main erosional events, during the messinian and the late oligocene and one hiatus event during the end of the cretaceous were introduced in the model. this missing overburden was reconstructed based on the well data and regional geological data (cati et al., 1987, grandic et al., 1997, wrigley et al., 2014). 4. model results the starting point of this analysis was the understanding of the hydrocarbon potential and the associated exploration risks of deep mesozoic plays. the results can be summarized as follows: • the risk of overmature conditions with consequent source depletion seems to be absent considering the low reconstructed geothermal gradient and related heat flow. maturity model results confirm that both source rocks are within the oil window and that they can efficiently generate and expel hydrocarbons (fig. 8); • there is a significant divergence between the quantity of hydrocarbons expelled and the quantity accumulated in the reservoirs, especially during the lower cretaceous (fig. 9). the main reason seems to be the timely mismatch between expulsion and the deposition and compaction of a working seal. figure 6: facies model with the definition of petroleum system elements across the studied seismic line. mazzuca et al.: exploring the potential of deep targets in the south adriatic sea: insight from 2d basin modeling of the croatian offshore geologia croatica 243 after calibrating and simulating the 2d model, the chart with all the features of the petroleum system was completed (fig. 10). the biggest risk for the efficiency of the studied petroleum systems is the late completion of the traps for cretaceous/eocene reservoirs (dark blue row). the seal rock was deposited in the oligocene and compaction is ongoing through the miocene, when most of the hydrocarbons were expelled. a more efficient compaction can be expected in the central part of the basin, where a thicker sequence of oligocene and miocene sediments can be observed. the lower jurassic reservoir could have the best working petroleum system assuring hydrocarbon accumulations figure 7: geothermal gradient in the south adriatic croatian offshore. figure 8: maturity stage at the present day: the lower jurassic source is in the main oil window and the triassic source rock is mainly in the oil window and partially in the wet gas window. geologia croatica 68/3geologia croatica 244 figure 9: graph showing the total hydrocarbons expelled (orange), accumulated (red) and lost (green) in the system. figure 10: petroleum systems elements chart derived from a pseudo-well in the central part of the 2d basin. (fig.10). in fact, the triassic source rock starts to expel when the reservoir is deposited and the lias source works as a seal. a pseudo-well was introduced in the central part of the basin. in this area the reconstructed burial history shows that the source rocks are buried at their deepest and up-dip fluid migration, towards the highs of both structural traps, was possible. the significant difference of generation between the two source rocks is related to the slow deposition of sediments in the basin between 180 and 30 ma (fig. 11). the jurassic source barely reached 50% transformation of kerogen, which explains the minor contribution to the accumulations observed in the model (fig. 11). the final migration model shows that fluid saturated structures are present in both plays (fig. 12). also, considering the actual uncertainties, the total depths of the cretaceous traps are around 3500 m and 5500 m for jurassic traps, in water depth between 500 and 1200 m. this reservoir depth could have a negative impact on economic viability. 5. conclusions all the critical elements for a working petroleum system are present in the lower jurassic structural carbonate karst play and in the cretaceous slope calciturbidites play. the existence of liquid hydrocarbons coming from triassic and jurassic source rocks into the studied petroleum systems at the present day seems to be possible (fig. 8 and 12). for the structural karst play, which is highly under-explored, there are still uncertainties concerning reservoir quality (no porosity data) and efficiency (no well testing performed). for the mid-cretaceous/eocene platform margin, there are significant uncertainties related to the possibility of finding significant accumulation in the traps. in fact, a temporal mismatch between expulsion and the deposition and compaction of a working seal (messinian, top oligocene and top cretaceous) could have facilitated hydrocarbon leakage to the surface. mazzuca et al.: exploring the potential of deep targets in the south adriatic sea: insight from 2d basin modeling of the croatian offshore geologia croatica 245 figure 11: transformation of hydrocarbons (%) from kerogen through time at pseudo-well location for both source rocks. 6. discussion at the end of this study, the following points remain open for discussion in order to reduce risk in the area: • new ongoing exploration activities, since the last licensing round in 2014, could reduce the uncertainties related to the missing hard-dataset. this could facilitate well seismic calibration, core analyses and source rock geochemical characterization; • build a 3d petroleum systems model, when a new 3d seismic survey is acquired, to quantify the hydrocarbons in the system passing from play to prospect analysis; figure 12: potential new accumulations in lower jurassic and mid cretaceous traps. geologia croatica 68/3geologia croatica 246 • create a detailed back stripping structural restoration model, considering triassic salt tectonics, to better understand the structural timing of the potential traps and the associated model migration pathways. acknowledgment the authors would like to thank darko spahic for providing advice, guidance and expertise on all aspects of this work. we would also like to especially thank björn wygrala for many useful suggestions and advice. finally, we wish to express our gratitude to alan monahan for his language editing. references al-hajeri, m.m., al saeed, m. et al. (2009): basin and petroleum system modeling: oilfield review summer, 21, no. 2, copyright © schlumberger. andrè, p. & doulcet, a. (1991): rospo mare field e italy, apulian platform, adriatic sea.– in: foster, n.h. & beaumont, e.a. (eds.): treatise of petroleum geology, atlas of oil and gas fields, stratigraphic traps ii, 29–54. balogh, k., colantoni, p., guerriera, f., majer, v., ravaszbaranyai, l., renzulli, a., veneri, f. & albertini, c. (1994): the medium-grained gabbro of the jabuka islet (‘‘scoglio del pomo’’, adriatic sea).– giorn. geol., 56/2, 13–25. bejdic, g. (2012): exploration in croatia.– iene’s international workshop, athens. billi, a., gambini, r., nicolai, c. & storti, f. (2007): neogenequaternary intraforeland transpression along a mesozoic platform-basin margin: the gargano fault system – adria, italy.– geosphere, v.3, 1–15. casero, p. (2004): structural setting of petroleum exploration plays in italy.– in: special volume of the italian geological society for the igc 32 florence 2004, 189–199. casero, p. & bigi, s. (2013): structural setting of the adriatic basin and the main related petroleum exploration plays.– marine and petroleum geology, 42, 135–147. cati, a., sartorio, d. & venturini, s. (1987): carbonate platforms in the subsurface of the northern adriatic area.– mem. soc. geol. ital., 40, 295–308. del ben, a. (1994): seismic heat flow study of the southern adriatic basin.– bullettino di geofisica teoretica ed applicata, vol. xxxvi. grandic, s. et al. (1974): review of the hydrocarbon plays in the croatian offshore and periadriatic areas.– nafta, 7–8. grandic, s., boromisa-balas, e. & sustercic, m. (1997). exploration concept and characteristics of the stratigraphic and structural models of the dinarides in croatian onshore area – part ii: hydrocarbon consideration.– nafta, 48/8–9, 249–266. grandic, s., boromisa-balas, e., sustercic, m. & kolbah, s. (1999): hydrocarbon possibilities in the eastern adriatic slope zone of croatian onshore.– nafta, 50/2, 51–73. grandic, s. & markulin, z. (2000): triassic syn-rift euxinic basins as a factor of exploration risk in the croatian onshore area.– in: proceedings of international symposium of petroleum geology, april 22–24, 1999, nafta sp. issue, 41–50. grandic, s., kratkovic, i., kolbah, s. & samarzija, j. (2004): hydrocarbon potential of stratigraphic and structural traps of the ravni kotari area – croatia.– nafta, 55/7–8, 311–327. grandic, s. (2009): periplatform clastics of croatian offshore and their petroleum geological significance.– nafta, 60/9, 503–511. grandic, s. & kolbah, s. (2009): new commercial oil discovery at rovesti structure in south adriatic and its importance for croatian part of adriatic basin.– nafta, 60/2, 68–82. grandic, s., kratkovic, i. & rusan, i. (2010): hydrocarbon potential assessment of the slope deposits along the sw dinarides carbonate platform edge.– nafta 61/7–8, 325–338. grandic, s. et al. (2013): peri-adriatic platforms proximal talus reservoir potential.– nafta, 64/2, 147–160. kolbah, s.: the croatian data for the global heat-flow database. new developments in the geothermal measurements in boreholes, regional analyses of the geothermal data.– klein koris-berlin. mattavelli, l., novelli, l. & anelli, l. (1991): occurrence of hydrocarbons in the adriatic basin.– spec. publ. eapg, 1, 369–380. mattavelli, l., pieri, m. & groppi, g. (1993): petroleum exploration in italy: a review.– marine and petroleum geology, 10, 410–425. nikolai, c. & gambini, r. (2007): structural architecture of the adria platform and basin sytem.– boll. soc. it. spec. issue no. 7. shiner, p., bosica, b. & turrini, c. (2013): the slope carbonates of the apulian platform – an under-explored play in the central adriatic.– aapg, barcelona. tari, v. (2000): evolution of the northern and western dinarides: a tectonostratigraphic approach.– egu, special publication series, 1. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: paleogeography, main events and depositional dynamics.– paleo, 222, 333–360, elsevier b.v. wrigley, r., marszalek, a., rodriguez, k. & hodgson, n. (2014): offshore croatia – hunting ‘big oil? in the centre of europe.– first break, vol. 32, 61–68. manuscript received march 12, 2015 revised manuscript accepted september 08, 2015 available online october 31, 2015 2021 | 74/1 | 73–83 | 9 figs. | 2 tabs. | 1 pl. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction due to its wide coverage, easy accessibility, and high economic efficiency, remote-sensing imagery has been broadly applied to dynamic monitoring of land use, agricultural surveying (liu et al., 2017; xie et al., 2017; jiang et al., 2018; howari et al., 2019), urban-survey planning (wang et al., 2016; sun et al., 2017; hu et al., 2018), mineral-resource development (fan et al., 2021), environmental monitoring and investigation (wang et al., 2018; ming et al., 2018; alijagić & šajn, 2020), basic geological and resource surveying (shi et al., 2017; xie et al., 2020), geological disaster and emergency investigation (guo et al., 2009; zhou et al., 2017; wei et al., 2017), geological-hazard monitoring, and emergency investigation (zhao et al., 2017; zhong et al., 2018). with continuous development and progress of sensor and computer technology, multispectral remote-sensing imagery has developed from low–medium to high spatial, spectral, and radiation reso lution. remote-sensing images have great potential for natural-resources surveys. hyperspectral remote sensing is a technology by which image data are divided into many very narrow and continuous spectral datasets to detect the visible, near infrared, mid-infrared, and thermal-infrared bands of the electromagnetic spectrum (hunt, 1989; clark et al., 1990; pu & gong, 2000; tong et al., application of an airborne hyper-spectral survey system casi/sasi in the gold-silver-lead-zinc ore district of huaniushan, gansu, china yuhai fan1,2,3,*,yuqing wan2, hui wang2, xingke yang1, min liang2,chunjuan pan2, shaopeng zhang1,2, wenbo wang2 and furong tan2 1 chang’an university, school of earth science and land and resources, xi’an, 710054 china; (*corresponding author: 170269854@qq.com) 2 geological exploration institute of aerial photogrammetry and remote sensing bureau, xi’an, 710199 china 3 yulin university, school of management, yulin, 719000 china doi: 10.4154/gc.2021.04 abstract the airborne hyper-spectral survey system casi/sasi, which has an integrated system for gathering both image an spectral data, is at the cutting edge developments in the remote-sensing field. it can be used to directly identify surface objects based on diagnostic spectral chara­ cteristics. in this paper, the casi/sasi were used in the huaniushan gold-silver-lead-zinc ore district–gansu to produce a lithologic map, identify altered minerals, and map the mineralized-alteration zones. radiometric correction, radiometric calibration, atmospheric correction (spectral reconstruction), and geometric corrections were carried out in envi to pre-process the measured data. a fieldspec ® pro fr portable spectrometer was used to obtain the spectral signatures of all types of rock samples, ore deposits, and mineralized-alteration zones. we extracted and analyzed the spectral characteristics of typical alteration minerals. on the basis of hyper-spectral data, ground-spectral data processing, and comparative analysis of the measured image spectrum, we used the spectral-angle-mapping (sam) and mixture-tuned matchedfiltering (mtmf) methods to perform hyperspectral­alteration mineral mapping of wall rock and mineralized­alteration­zone hyperspectral identification. hyperspectral­remote­sensing geological­classification maps were produced as well as distribution maps of all kinds of alteration minerals and mineralized-alteration zones. based on geological comprehensive analysis and field investigations, the range of mineral alteration was proven to be the same as shown by the remote-sensing imagery. indications are that airborne hyperspectral-remote-sensing-image casi/sasi offer good application results and show a promising potential as a tool in geological investigations. the results will provide the basis for hyperspectral remote-sensing prospecting in the same or similar unexplored areas. 2006), thereby offering a high spectral resolution. many unrecognized substances in wide-band remote sensing can be detected in the hyperspectral data and quantitatively studied (clark et al., 2003; tang et al., 2006; schaepman et al., 2009; kruse, 2012; van der meer et al., 2012). because various minerals and rocks have diagnostic spectral-characteristic-absorption bands in the range of 400–2,500 nm, hyperspectral remote sensing can better capture the characteristics of minerals. based on these characteristic spectral features, mineral compositional information can be inverted and identified. thus, classification, mapping of rocks and mineral-resource exploration can be performed (clark et al., 2003; gan & wang, 2007; zhang et al., 2011; wei et al., 2017). since the mid-1980s, with the rapid development of key technologies such as data acquisition, radiation calibration, spectral reconstruction, and data processing, many applications of hyperspectral remote-sensing technology to the fields of geology and mineral resources have been performed by researchers around the world, resulting in some noteworthy new achievements (hunt, 1989; clark et al., 1990, 2003; pieters & mustard, 1988; kruse et al., 1990; clouds, 1996; yessy et al., 2011; liu et al., 1999; gan et al., 2000; wang et al., 2000; yan et al., 2004; wang et al., 2010). at article history: manuscript received may 09, 2019 revised manuscript accepted february 03, 2021 available online february 28, 2021 keywords: airborne hyper-spectral survey system casi/sasi, huaniushan gold-silver-lead-zinc ore district, hyperspectral-alteration mineral mapping of wall rock, mineralized-alteration-zone hyperspectral identification g eo lo gi a c ro at ic a geologia croatica 74/174 present, hyperspectral data are playing an increasingly important role in rock and mineral identification (drake, 1995; bishop et al., 2011; pour et al., 2013), archaeology (chen et al., 2017), solid-mineral and oil and gas exploration (guo et al., 2012; wang et al., 2007; hu et al., 2009; zhou, 2014), environmental protection and monitoring (zhao et al., 2013; everitt et al., 1988; trenc et al.,1999; wan et al., 2003; howari et al., 2019), vegetation classification and detection (li et al., 2014), and lunar and planetary exploration (bandfield, 2002; lapotre et al., 2017), among others. here, the casi/sasi data were used in the huaniushan gold-silver-lead-zinc ore district–gansu to produce a lithologic map, identify altered minerals, and map the mineralizedalteration zones. a fieldspec® pro fr portable spectrometer was used to obtain the spectral signatures of all types of samples for rock, ore deposits, and mineralized-alteration zones. the spectral characteristics of typical minerals related to gold-silver-lead-zinc ore were extracted and analysed. combined with worldview-2 high-resolution satellite remote sensing images and geological data, the remote sensing geological work of gold, silver, lead and zinc deposits in this area was carried out. finally, hyperspectral-alteration mineral mapping of wall rock and hyperspectral identification of mineralizedalteration zones were performed in the study area, and their effects were verified by field investigation. these results will provide the basis for hyperspectral remote-sensing prospecting in the same or similar unexplored areas. 2. geological framework the gold, silver, lead and zinc metallogenic region of huaniushan is located in beishan, gansu province. since the 1950s, the gold and silver deposit of huaxishan, tungsten-molybdenum deposits of huadongtan, the molybdenum deposit of huaheitan, gold deposit of huaniushan, copper-iron-tin deposit of huaxitan, and silver-gold deposit of nanquan have been discovered one after another, such that the area is now recognized as one with a concentration of noble and rare metals (nie et al., 2002; xi’an institute of geology and mineral resources, 2006). the huaniushan–heishan–shuangyingshan rift belt was a site of geotectonic activity in the early palaeozoic, belonging to the northern margin of the dunhuang massif active belt of the beishan tarim plate (cao et al., 2008; dai, 2010). the main strata exposed in the mining area belong to the pingtoushan formation of the upper jixian system, which can be further divided into three lithologic segments: jxp3 c, jxp3 b, jxp3 a. it is a set of shallow-sea facies shallow metamorphic clastic rock–carbonate rock– basic–intermediate volcanic rocks formation. it is the main ore-hosting horizon in the area (yang et al., 2010) (figure 1). the faults in the mining area trend mainly ew, nw, ne and sn, with a scale that extends from hundreds to thousands of metres. the broken bandwidth is several metres to tens of metres. rocks on both sides of the fault zone are broken. mylonite, fault breccia and fault scratches occur in the fault zone. the fault shows the characteristics of multi-stage activity (dai, 2010). the folds are mainly e-w trending complex-fold structures, with n-s, ne-sw, and nw-se trending small-scale secondary folds superimposed at a later stage. magmatic activity was obviously controlled by e-w– trending and nw-se trending tectonic belts. emplacement took place during the variscan and indosinian epochs (he et al., 2012). influenced by multiple magmatic intrusions and hydrothermal activities, the rocks underwent relatively strong alterations (diopside-tremolite, skarnization, uralitization, zoisitization, and sericitization, etc.) (dai, 2010; yang et al., 2010). 3. methods here, the casi/sasi data were used as the main information source to carry out remote sensing geological work on gold, silfigure 1. geological map of the huaniushan gold-silver-lead–zinc ore district (1. huaniushangroup in middle ordovician; 2. third member of the pingtoushan formation of the jixian system; 3. second member of the pingtoushan formation of jixian system; 4. the first member of the pingtoushan formation of the jixian system; 5. the second-stage granite of the indosinian period; 6. the first-stage granite of the indosinian period; 7. the granite of the middle variscan period; 8. porphyry granite of the middle variscan period; 9. quartz diorite of the middle variscan period; 10. altered peridotite of the early variscan period; 11. granodiorite of the early variscan period; 12. reverse faults; 13. compressive-torsional faults; 14. torsional faults; 15. faults of unknown nature; 16. stratigraphic boundary; 17. anticline; 18. syncline; 19. lamprophyre veins; 20. north finger; 21. coverage area of hyperspectral data). g eologia c roatica fan et al.: application of an airborne hyper-spectral survey system casi/sasi in the gold-silver-lead-zinc ore district of huaniushan, gansu, china 75 ver, lead and zinc mines in coordination with ground synchronous testing and radiometric calibration. a fieldspec ® pro fr portable spectrometer was used to obtain the spectral signatures of all types of samples for rock, ore deposits, and mineralizedalteration zones. and the main mineral spectrum library was established. finally, hyperspectral-alteration mineral mapping of wall rock and hyperspectral identification of mineralized-alteration zones were performed in the study area, and their effects were verified by field investigation (figure 2). 3.1. data acquisition the casi/sasi data used in this study were acquired by the casi/sasi/tasi airborne imaging spectrometry system (ahis) developed by itres canada. casi–1500 and sasii–600 sensors, the icu central controller, and a series of precise geometricand radiation-correction instruments (gps equipment, posav310, ils solar irradiance measurement instrument, threeaxis stabilized platform pav30 and imu inertial navigation system) constitute the vnir–tir aviation hyperspectral-measurement system. two kinds of data, 380–1,050 nm (casi) and 950–2450 nm (sasi), are provided. the total number of bands reaches 388, and the spatial resolution reaches the sub-metre level. three imaging modes are available: spatial, spectral, and full-frame. the main technical indicators are listed in table 1. the system is mainly used in mineral-resource exploration, environmental monitoring, disaster detection and management, and other fields, providing technical support for the development of quantitative remote-sensing technology in china (yang et al., 2015). on september 6, 2012, a yun–5 small multi-purpose aircraft carrying a hyperspectral sensor was used to collect test data over the huaniushan gold, silver, lead, and zinc mine in gansu province. the flight altitude was 1,500 m. two hyperspectral datasets were obtained from 10 km2 airstrips. the flight path is shown in figure 1. (coverage area of hyperspectral data). the weather was clear and cloudless on the day of data acquisition. hyperspectral data included the casi vnir band and the sasi swir band. there were 36 bands of casi data. the spectral-coverage range was 380–1,045 nm, the spectral resolution was 18 nm, and the spatial resolution was 1 m. sasi data consist of 101 segments with a spectral coverage of 950–2450 nm, a spectral resolution of 15 nm and a spatial resolution of 2.25 metres. in the process of aerial flight survey, field spectral tests were carried out at the same point on the ground in the main mineralized area. 3.2. spectrum test spectrum testing is based on the fieldspec® pro fr portable spectrometer produced by the american asd company. it is suitable for remote-sensing measurement, crop monitoring, forest research, industrial-lighting surveys, oceanographic research, and mineral exploration. wavelength range: 350–2500 nm, detector: 350–1050 nm, low noise 512 elements pda, 1000–1800 nm and 1800–2500 nm, two ingaas detector units, pe refrigeration constant temperature. the purpose of spectrum testing is to determine the absorption and reflection bands of the different rocks or minerals that correspond to each band of the hyperspectral remote-sensing image, and to find the absorption and reflection bands of different minerals or rocks. typical rocks and minerals are extracted by methods of difference, ratio, principal component, and classification in different bands, and spectral inversion of typical rocks or minerals from high-resolution remote-sensing images is realized. survey points are laid out according to the survey method of the geological section. profile measurements cross the main lithostratigraphic and mineralized-alteration zones and are collected according to at least one test sample per typical stratigraphic unit. rock-test points on profiles should be encrypted according to lithological changes or testing of multiple samples at the same point, including typical lithology related to mineralization, rock in fractured zones, altered rocks, and hydrothermal figure 2. technical flow chart. table 1. main technical parameters of the casi/sasi airborne imaging spectrometer. parameters spectral range pixel number per row number of spectral channels spectral bandwidth frame frequency (full band) angle of field /(°) instantaneous field of view angle /(°) noise–signal ratio(peak value) absolute radiation accuracy /% casi–1500 380–1050nm 1470 288 2.3nm 14 40 0.028 >1100 <2% sasi–600 950–2450nm 640 100 15nm 100 40 0.07 >1100 <2% g eo lo gi a c ro at ic a geologia croatica 74/176 veins. the sample size is 3 cm×6 cm×9 cm. gps positioning is used for each sampling point, coordinate data are collected, field photographs are taken, and each typical rock sample measu red is identified and retained in order to verify the accuracy of spectraltest results. at least one set of spectral curves was collected from each ore sample, and the parameters, such as the sample name, sample number, light-source type, test time, lens degree and distance from the sample, were recorded in detail. collect the spectral information of weathering surface and fresh surface of rock. three samples were collected from different directions of weathering surface. subsequently, the rock was cut and five samples were collected on the fresh rock surface. the basic parameters of the characteristic-absorption peaks of minerals and water are as follows: about 1400 nm: oh–absorption peak; 1900–2000 nm: water-absorption peak: high-temperature, high-crystallinity, good peak shape; 2200 nm: al–oh (kaolinite, muscovite, pyrophyllite); 2250–2300 nm: fe–oh, mg–oh (chlorite, biotite); 2300–2400 nm: carbonate, mg–oh (talc, tremolite). the spectral data obtained in the field are processed and the relative abundances of minerals are determined by the ratio of the characteristic-absorption peaks of minerals to that of water. the results of the ratio calculation can be divided into six categories: absorption strength, integral strength, half width, reflectance, intensity ratio, and central wavelength. the higher the value, the higher the mineral abundance. based on the results of rock and mineral analysis, the spectral curves of minerals corresponding to the standard spectral library were compared and analyzed, and the distribution regularity of ores’ characteristic spectral bands was summarized. 3.3. data processing because of the influence of flight-platform coordinates, flight attitude, the sun, the atmosphere, and other factors, the original remote-sensing image is distorted and there are errors in space. thus, before extracting mineral-alteration information, casi/sasi data should first be processed. casi and sasi data (ye et al., 2011) processing include six main steps: data browsing, spatial resampling, band matching, geometric correction, atmospheric correction, and radiometric calibration (ye et al., 2011; sun et al., 2015). after processing, the hyperspectral image is shown in figure 3. 3.3.1. data browsing, removal of repetitive bands, selection of bands the hyperspectral data were checked and found to be duplicated between 950 nm and 1,047 nm. the duplicated spectra in sasi were removed. several bands near the 1,400 and 1,900-nm spectra (which correspond to atmospheric windows and are heavily affected by water and gas) increase the amount of data calculation and have no research value, so they were removed (figure 4). after band removal, 92 hyperspectral bands remained. 3.3.2. spatial resampling because of the inconsistent spatial resolution of the casi/sasi data, spatial resampling is necessary. there are three common sampling methods: nearest, bilinear-interpolation, and cubic-convolution. for this study, the bilinear-interpolation method was chosen. the results obtained by this method are smoother and suitable for continuous data. 3.3.3. casi and sasi band matching the acquired casi/sasi data are positioned 10 pixels (2.25m/ pixel) differently in space. the method of selecting ground-control points is based on casi data and the geometric correction of sasi data by a quadratic polynomial. then, casi and sasi band matching is carried out to generate hyperspectral data in the range of 368.7–2,450.0 nm. 3.3.4. geometric correction the hyperspectral data has two spectral ranges, 380-1050nm and 950-2450nm. firstly, preliminary geometric correction of the data is completed based on the data parameters of the system. then, figure 3. hyperspectral remote-sensing image of the huaniushan gold-silver-lead-zinc ore district (using airborne hyperspectral-image casi/sasi data) (r:b25, g:b42, b:b87). g eologia c roatica fan et al.: application of an airborne hyper-spectral survey system casi/sasi in the gold-silver-lead-zinc ore district of huaniushan, gansu, china 77 based on the collected basic geographic data and the measured control points, such points are selected and the hyperspectral data are geometrically corrected by quadratic polynomials. the selection of control points on maps (or on the spot) and images can clearly identify and precisely locate the obvious object points, which do not change with time. the number of control points in a ground measurement is large and the distribution is uniform. 3.3.5. image mosaic the results of the two-airstrip correction are a mosaic. an overlapping check is carried out before the mosaic, and the overlap tolerance between the airstrips meets the technical requirements. in the mosaic, the image with high resolution, new time, less cloud, and good quality should be preserved as far as possible. the mosaic line allows dislocation, blurring, duplication, and halos to be avoided. 3.3.6. radiation calibration in this paper, the spectral curves of marble, granite porphyry, skarn and lamprophyre vein measured in the field were compared with the spectral reconstruction results of image features. the correspondence between the two is 98%, which meets the needs of this alteration information extraction. 4. hyperspectral remote-sensing characteristics of the gold, silver, lead, and zinc metallogenic area in huaniushan 4.1. spectral-angle-mapping (sam) spectral-angle-mapping (sam) is an automatic classification method, which compares the spectrum in the image with the spectrum in the spectral library, and determines their similarity by calculating the spectral angle between them. figure 4. field-spectral curve of rocks in the study area (1. marble, 2. granite porphyry, 3. skarn, 4. lamprophyre, 5. phyllite). figure 5. geology classification figure of hyperspectral remote sensing in the study area. g eo lo gi a c ro at ic a geologia croatica 74/178 according to the spectral library established by the reflected spectral curve of each feature in the collected image, spectral curve reflected were divided into 15 categories, including: alluvial material, phyllite, schist, marble, hornstone, skarn, monzonite 1, monzonite 2, granite 1, granite 2, granodiorite, granite-porphyry, plagioclase granite porphyry, lamprophyre, mineralized alteration zone. at the same time, the typical features (vegetation, water, cloud, etc.) were also classified. the geological classification figure of hyperspectral remote sensing in the study area was obtained after classification and post-processing (figure 5). 4.2. hyperspectral mapping of altered minerals in the surrounding rocks under the influence of multi-stage magmatic intrusion and hydrothermal activity, the rocks in the huaniushan gold-silver-leadzinc metallogenic area have undergone relatively strong hydrothermal alteration, resulting in sericitization, chloritization, silicification, muddification (kaolinite), carbonation (calcite, iron carbonate rock), skarnization (diopside, garnet, etc.), potash feldspar (jarosite) and other altered minerals (dai, 2010, yang et al., 2010). they are of great significance to the formation of gold, silver, lead, and zinc deposits in the study area. the depth of the absorption band is closely related to the content of these minerals in the rocks. the spectral characteristics of various types of altered mineral samples in the study area are shown in figure 6. according to the characteristic-absorption spectra of the altered minerals (reflectivity data→ minimum noise separation (mnf)→ ppi pixel purification→ extracting end element training samples→ hyperspectral mapping of altered minerals in surrounding rock (sam)), the mineral extraction method of hyperspectral remote sensing was used to extract and identify the altered minerals (lin et al., 2011; wang et al., 2010). alteration minerals are mainly distributed in the marble section of the pingtoushan formation of the jixian system, which is the main orebearing horizon in the area and intruded by the indosinian granite body. in addition, there are dozens of granite porphyry and lamprophyre dykes interpenetrating and intruding the country strata. marble has extensive contact with rock mass and strongwall rock alteration. all 92 bands of the test data were transformed by mnf, and 20 bands with high eigenvalue were output. the pixel purity index (ppi) of these 20 bands was calculated. the number of iterations was 10000 and the noise threshold was 3. through pixel purity index (ppi), the purest pixel in the data was extracted and the sample space was established. the unknown spectrum in the field measured spectrum library of altered minerals was matched with that in the standard spectrum library. a series of matching coefficients was obtained to determine the mineral types. based on the characteristic absorption spectra of qualitative mineral types and the method of spectral angle classification (sam), the distribution maps of various altered minerals in the study area were obtained (figure 7). 4.3. hyperspectral recognition of the mineralized-alteration zone ore bodies and veins in the huaniushan au-ag-pb-zn metallogenic area are generally finer, and mostly more than ten centimetres in diameter?. the spectral curves of galena, sphalerite, and other ores are relatively straight, and there are no obvious characteristic-absorption bands. however, iron-oxide outcrops (limonite, haematite, jarosite) are a significant indicator of this type of mineralized surface (plate 1). chemical characteristics generally figure 6. spectral curves of all kinds of alteration minerals in the study area (1. kaolinite, 2. silicification, 3. k-feldsparization 4. fe–carbonate rocks, 5. chloritization, 6. calcite, 7. sericite, 8. diopside). g eologia c roatica fan et al.: application of an airborne hyper-spectral survey system casi/sasi in the gold-silver-lead-zinc ore district of huaniushan, gansu, china 79 contain fe2+, fe3+, and there are characteristic-absorption and strong-reflection bands in the visible band (gan et al., 2003). these are easy to identify via remote-sensing images, which have a particular guiding significance for discovering gold, silver, lead and zinc ore bodies (veins) in the study area. in order to locate the ore bodies and veins in the gold-silverlead-zinc metallogenic area of the study area, we used the method of looking for surface-iron oxides and field verification to confirm it. the spectral curves of several iron oxides were collected on the image, and each spectral curve was filtered by a mixed-modulation-matching filter. the average value of the filtered image shows that the metal cations of iron-oxide (jarosite) in the study area absorb strongly at 0.45 m, 0.55 m, 0.85 m, 0.90 m, and 0.94 m, have strong absorption bands between 0.9 m and 1.0 m, and have relatively strong reflection between 0.6 m and 0.8 m. hydroxy anions absorb strongly between 2.2 and 2.3 m (figure 8). their characteristic-absorption bands and the corresponding bands of sasi images are shown in table 2. mixed-modulationmatched filtering is used to map iron-oxide minerals from the transformed images. the consistency between the ore vein extracted and the ore vein verified in the field were 85% (figure 9). therefore, the extraction effect was good, which was worthy of application and promotion. 5. conclusion on the basis of obtaining a large amount of geological data, airborne hyperspectral remote-sensing data (casi/sasi) and field rock and mineral spectra of the huaniushan gold-silver-lead-zinc mining area, spectral testing of rock, ore deposit and alteredmineralization zone samples was carried out through spectral testing and rock and mineral sampling analysis. finally, hyperspectral mapping of wall rock-altered minerals and hyperspectral identification of the altered-mineralization zone were performed in the study area. combined with field investigation and verification, the following conclusions were obtained: 1) the alteration-mineral-information maps of the surrounding rocks in the study area show that the rocks in the huaniushan gold-silver-lead-zinc metallogenic area have undergone relatively strong hydrothermal alteration due to the influence of multiple magmatic intrusions and hydrothermal activities. alteration mine rals are mainly distributed in the marble section of the pingtoushan formation of the jixian system, mostly by sericitization, chloritization, silicification, muddification (kaolinite), carbonation (calcite, iron carbonate rock), skarnization (diopside, garnet, etc.), potassium feldspar (jarosite), etc. the distribution range of altered minerals is basically consistent with the results of field investigations, indicating that hyperspectral imaging can provide accurate and reliable information for prospecting. 2) the surfaces of ore bodies and veins in the huaniushan gold-silver-lead-zinc metallogenic area are marked by iron-oxide table 2. iron minerals’ characteristic-absorption spectrum and the corresponding image band of casi/sasi. ions and groups characteristic absorption spectra /µm corresponding to sasi band typical minerals fe2+, fe3+ fe2+: 1.1–2.4; fe3+: 0.45, 0.55, 0.85, 0.90, 0.94 b1–b6, b22–b26 limonite, hematite, jarosite figure 7. distributions of all kinds of alteration minerals in the study area (kaolinite, calcite, sericite, diopside, chlorite, silicification, jarosite, fe–carbonate rocks). figure 8. spectral curve of jarosite in the study area (found). g eo lo gi a c ro at ic a geologia croatica 74/180 outcrops (limonite, hematite, jarosite). the mixed-modulationmatched-filtering method is used to identify and extract the mineralized alteration zone containing fe2+, fe3+. the results of extraction basically agree with the field-verification results, which have a certain guiding significance for finding gold, silver, lead, and zinc ore bodies (veins) in the study area. 3) this paper indicates that airborne hyperspectral-remotesensing-image casi/sasi data offer good application results and show promising potential in geological exploration. our results will provide the basis for hyperspectral remote-sensing prospecting in the same or similar unexplored areas. acknowledgement this research was financially supported by china geological survey project (no. 12120113073000; no.dd20160117) and national key basic research program of “973” project (2015cb453000). thanks to the anonymous reviewers and editors of tea fluksi, lidija galović, and julie robson for their suggestions on the paper. references alijagić, j. & šajn, r. (2020): application and improvement of soil spatial distribution mapping using advanced modelling techniques.– geologia croatica, 73/1, 69–84. doi: 10.4154/gc.2020.01 bandfiel, d. (2002): globe mineral distribution on mars.– geophysical res., 107 (e6), 5024. bishop, c.a., liu, j.g. & mason, p.j. (2011): hyperspectral remote sensing for mineral exploration in pulang, yunnan province, china.– international journal of remote sensing, 32, 2409–2426. doi: 10.1080/01431161003698336 bronge, l.b. & naslund, l.b. (2002): wetland classification for swedish c– orine land cover adopting a semi–automatic interactive approach.– canadian jounral of remote sensing, 28/2, 139–155. cao, l., shan, l. & zhang, y.l. (2008): metallogenetic types of lead–zinc deposit and prospecting direction in beishan area.– resources environment & engineering, 22/1, 26–31. (in chinese with english abstract). chen, f., jiang, a., tang, p., yang, r. & zhou, w. (2017): multi–scale synthetic aperture radar remote sensing for archaeological prospection in han hangu pass, xin’an china.– remote sensing letters, 8, 38–47. doi: 10.1080/2150704x. 2016.1235812 clark, r.n., king, t.v.v., klejwa, m., swayze, g.a. & vergo, n. (1990): high spectral resolution reflectance spectroscopy of minerals.– j. geophys. res., 95, 12653–12680. doi: 10.1029/jb095ib08p12653 clark, r.n., swayze, g.a., livo, k.e., kokal,y.r.f., sutley, s.j., dalton, j.b., mcdougal, r.r. & gent, g.a. (2003): imaging spectroscopy: earth and planetary remote sensing with the usgs tetracorder and expert systems.– jourmal of geophysical research, 108/e12, 1–44. doi:10.1029/2002.je001847 clouds, e.a. (1996): hyperspectral geological remote sensing: evaluation of analytical techniques.– int. j. remote sensing, 17/12, 2215–2242. dai, w.j. (2010): metallogenic study of huaniushan au–ag–pb–zn deposit, beishan area, gansu province.– geology and mineral resources of south china, 3, 25–33. (in chinese with english abstract). drake, n.a. (1995): reflectance spectra of evaporite minerals (400–2500 nm): applications of remote sensing.– int. j. remote sensing, 16/14, 2555–2571. doi: 10.1080/01431169508954576 everitt, j.d., escobar, d.e., gerbermann, a.h. & alanizl, m.a. (1988): detecting saline soils with video imagery.– photogramm. eng. remote sensing, 54, 1283–1287. fan, y., wang, h., yang, x., liang, m., pan, c., zhang, s., wang, w. & tan, f. (2021): application of high resolution remote sensing technology for the iron ore deposits of the west kunlun mountains in china.– geologia croatica, 74/1, 57–72. doi: 10.4154/gc.2021.03 gan, f.p., wang, r.s., guo, x.f. & wang, q.h. (2000): extraction for rock and ore deposits information and prospects for application of geology using hypersperctral remote sensing – tibet plateau as test sample.– remote sensing for land & resources, 12/3, 38–44. (in chinese with english abstract). gan, f.p. & wang, r.s. (2007): the application of the hyperspectral maging technique to geological investigation.– remote sensing for land & resources, 74/4, 57–60. (in chinese with english abstract). gan, f.p., wang, r.s., ma, a.n. & zhang, z.g. (2003): a iteration extracting based on spectral match filter (smf).– journal of image and graphics, 8/2, 147–150. (in chinese with english abstract). gong, m.t. & feng, p.l. (2014): preliminary study on the application of hyperspectral imaging in the classification of and identification chinese traditional pigments classification a case study of spectral angle mapper.– sciences of conservation and archaeology, 26/4, 76–83. (in chinese with english abstract). guo, j., chang, x., gao, y., sun, x., sun, g. & huang, c. (2009): lake level variations monitored with satellite altimetry waveform retracking.– ieee journal of selected topics in applied earth observations and remote sensing, 2, 80–86. doi: 10.1109/jstars.2009.2021673 guo, n., guo, k., zhang, t.t., liu, t.h., hu, b. & wang, c.w. (2012): hydrothermal alteration distribution model of the jiama (gyama) copper-polymetallic deposit based on shortwave technique.– acta geoscientica sinica, 33/4, 641–653. (in chinese with english abstract). doi: 10.3975/cagsb.2012.04.24 figure 9. distribution of mineralized-alteration zones distribution in the study area. g eologia c roatica fan et al.: application of an airborne hyper-spectral survey system casi/sasi in the gold-silver-lead-zinc ore district of huaniushan, gansu, china 81 he, z.z., cao, j. & dong, q.w. (2012): geological characteristics of the gold deposits and prospecting idea at the east huaniushan in gansu beishan.– gan su metallurgy, 34/3, 74–78. (in chinese with english abstract). howari, f.m., aydaroos, f.a., nazzal, y., iqbal, j. & bou orm, n. (2019): hyperspectroscopic and microtopographic analysesof salt crust forms on arid, silty clay loam desert soils.– geologia croatica., 72/1, 43–49. doi: 10.4154/gc.2019.01 hu, p., tian, q.j. & yan, b.k. (2009): the application of hyperspectral remote sensing to the identification of hydrocarbon alteration minerals in qaidam basin.– remote sensing for land & resources, 80/2, 54–61. (in chinese with english abstract). hu, q., ma, r., chen, f., jiang, a. & wang, y. (2018): urban landscape monitoring based on high-resolution spaceborne terrasar–x data: a case study of nanjing city, china.– remote sensing letters, 9, 448–457. doi: 10.1080/2150704x.2018.1437289 hunt, g.r. (1989): spectroscopic properties of rocks and minerals.– in: carmichel, r.c.: practical handbook of physical properties of rocks and mine rals, crc press inc, boca raton, florida, 599–669. jiang, a., chen, f., liu, g. & tang, p. (2018): use of instantaneous gpr attribute integration in prospecting for ancient roads at the han hangu pass, xin’an, china.– remote sensing letters, 9, 429–437. doi: 10.1080/2150704x.2018.1433342 kokal, y. r.f., clark, r.n. & livo, k.e. (1998): mapping the biology and mineralogy of yellowstone national park using imaging spectroscopy.– summaries of the 7th annual jpl airborne earth science workshop, r.o. green, ed, aviris workshop, jpl publication, 97–21/1, 245–254. krusc, f.a. (2012): mapping surface mineralogy using imaging spectrometry.– geomorphology, 137/1, 41–56. doi: 10. 1016/j.geomorph. 2010.09.032 kruse, f.a., kierein, y.s. & boardman, j.w. (1990): mineral mapping at cuprite, nevada with a 63-channel imaging spectrometer.– photogrammetric engineering & remote sensing, 56/1, 83–92. lapotre, m.g.a., ehlmann, b.l. & minson, s.e.a. (2017): probabilistic approach to remote compositional analysis of planetary surfaces.– journal of geophysical research: planets, 122, 983–1009. doi: 10.1002/2016je005248 li, j., han, j.c., zhang, y. & cheng, k. (2014): research progress on hyperspectral remote sensing technology in monitoring crop nutrition.– modern agricultural science and technology, 24, 251–254. (in chinese with english abstract). li, m.z. & zhang, p.y. (2015): classification of wetland vegetation in hyperspectral remote sensing image based on sam algorithm.– forest engineering, 31/2, 8–13. (in chinese with english abstract). lin, n., yang, w.n. & liu, h.h. (2011): mineral endmember identification and information extraction based on hyperspectral remote sensing.– remote sensing information, 5, 114–117. (in chinese with english abstract). doi: 10. 3969/j. issn.1000–3177.2011.05.021 liu, d.c., xie, h.j., li, j.f., zhao, y.j. & huang, s.t. (1999): hyperspectral data processing and research on geological application in miao er shan district, guangxi province.– remote sensing for land & resources, 41/3, 65–71. (in chinese with english abstract). liu, h., zhu, h. & wang, p. (2017): quantitative modelling for leaf nitrogen content of winter wheat using uav–based hyperspectral data.– international journal of remote sensing, 38, 2117–2134. doi: 10.1080/01431161.2016.1253899 liu, k., zhao, d., fang, j., zhang, x. & zhang, q. (2017): estimation of heavy -metal contamination in soil using remote sensing spectroscopy and a statistical approach.– journal of the indian society of remote sensing, 45, 805–813. doi: 10.1007/s12524-016-0648-4 liu, l.j., pang, y., fan, w.y., li, z.y. & li, m.z. (2011): integration of airborne hyperspectral casi and sasi data for tree species mapping in the boreal forest, china.– remote sensing technology and application, 26/2, 131–136. (in chinese with english abstract). ming, y., cheng, l., yu, h. & wang, c. (2018): quantitative inversion of vegetation biochemical components based on hj1–a hsi in coal mining area.– journal of the indian society of remote sensing, 46, 69–79. doi: 10.1007/s12524017-0682-x nie, f.j., jiang, s.h., bai, d.m., wang, x.l., su, x.x., li, j. c., liu, y. & zhao, s. m. (2002): metallogenic studies and ore prospecting in conjunction area of inner mongolia autonomous region, gansu province and xinjiang uygur autonomous region (beishan mt.), northwest china.– beijing: geological publishing house:1–34. (in chinese). pieters, c.m. & mustard, j.f. (1988): exploration of crustal/mantle material for the earth and moon using reflectance spectroscopy.– remote sensing of environment, 24, 151–178. doi: 10.1016/0034-4257(88)90010-7 pour, a.b., hashim, m. & van genderen, j.l. (2013): detection of hydrothermal alteration zones in a tropical region using satellite remote sensing data: bau goldfield, sarawak, malaysia.– ore geology reviews, 54, 181–196. doi: 10.1016/j. oregeorev.2013.03.010 pu, r.l. & gong, p. (2000): hyperspectral remote sensing and its application.– beijing: higher education press, 1–100. (in chinese). schaepman, m.e., ustin, s.l., plaza, a.j., oainter, t.h., verrelst, j. & liang, s.l. (2009): earth system science related imaging spectroscopy – an assessment.– remote sensing of environment, 113 (supplement 1), s123–s137. doi: 10.1016/j.rse. 2009. 03. 001 shi, z., li, p., jin, h., tian, y. & chen, y. (2017): improving super-resolution mapping by combining multiple realizations obtained using the indicator geostatistics based method.– remote sensing, 9/8, 773. doi: 10.3390/rs9080773 sun, y., zhao, y.j., li, h.b., lu, d.h., tian, f., qin, k., yang, g.f., zhou, j.j. & liu, p.f. (2015): hyspex hyperspectral mineral mapping of asiha gold ore district in dulan county, qinghai province and its prospecting implications.– acta geologica sinica, 89/1, 195–203. (in chinese with english abstract). sun, z., wang, c., guo, h. & shang, r. (2017): a modified normalized difference impervious surface index (mndisi) for automatic urban mapping from landsat imagery.– remote sensing, 9/9, 942. doi: 10.3390/rs9090942 tang, p.k., li, y.l., li, g.b. & yan, b.k. (2006): imaging spectrometry remote sensing technology and its applications in geology.– mineral resources and geology, 20/2, 160–165. (in chinese with english abstract). doi: 10.3696/j. issn.1001–5663.2006.02.013 tong, q.x., zhang, b. & zheng, l.f. (2006): multidisciplinary applications of hyperspectral remote sensing.– beijing: electronic industry press: 1–54. (in chinese). trenc, n., morgan, k.t, m.m., donovan, r.n. & busbey, a.b. (1999): remote sensing analysis of selected terrestrial impact craters and a suspected impact structure in south korea using space shuttle photographs.– geologia croatica, 52/2, 203–215. van der meer, f.d., van der werff, h.m.a., van ruitenbeek, f.j. a.,hecker, c.a., bakker, w.h., noomen, m.f., van der meijde, m., carranza, j.m., de smeth, b. & woldai, t. (2012): multi-and hyperspectral geologic remote sensing: a review.– international journal of applied earth observation and geoinformation, 14/1, 112–128. doi: 10.1016/j. jag.2011.08.002. wan, y.q., zhang, f.l. & yan, y.z. (2011): the analysis of mineral and rock’s hyper-spectral library.– geo-information science, 3, 54–58. (in chinese with english abstract). wan, y.q., zhang, f.l. & yan, y.z. (2003): the application of the hyperspectral remote sensing technology to water environment monitoring.– remote sensing for land & resources, 14/3, 10–14. (in chinese with english abstract). wang, q.h., wang, r.s. & guo, x.f. (2000): application for discrimination of rock using hyperspectral remote sensing technique.– remote sensing for land & resources, 46/4, 39–43. (in chinese with english abstract). wang, r.s., gan, f.p., yan, b.k., yang, s.m. & wang, q.h. (2010): hyperspectral minera1 mapping and its application.– remote sensing for land & resources, 83/1, 1–13. (in chinese with english abstract). wang, j. & ogawa, s. (2017): analysis of dynamic changes in land use based on landscape metrics in nagasaki, japan.– journal of applied remote sensing, 11/1, 016022. doi: 10.1117/1.jrs.11.016022 wang, r., hu, y., wu, h. & wang, j. (2016): automatic extraction of building boundaries using aerial lidar data.– journal of applied remote sensing. 10/1, 016022. doi: 10.1117/1.jrs.10.016022 wang, x.c., tian, q.j. & guan, z. (2007): the extraction of oil and gas information by using hyperion imagery in the sebei gas field.– remote sensing for land & resources, 71/1, 36–40. (in chinese with english abstract). wang, z., yu, s., tao, q., liu, g. & hao, h. (2018): a method of monitoring three-dimensional ground displacement in mining areas by integrating multiple insar methods.– international journal of remote sensing, 39/4, 1199–1219. doi: 10.1080/01431161.2017.1399473 wei, j., ming, y., jia, q. & yang, d. (2017): simple mineral mapping algorithm based on multitype spectral diagnostic absorption features: a case study at cuprite, nevada.– journal of applied remote sensing, 11/2, 026015. doi: 10.1117/1.jrs.11.026015 wei, j. & sun, l. (2017): comparison and evaluation of different modis aerosol optical depth products over the beijing–tianjin–hebei region in china.– ieee journal of selected topics in applied earth observations and remote sensing, 10/3, 835–844. doi: 10.1109/jstars.2016.2595624 xi’an institute of geology and mineral resources (2006): the prospecting potential of mineral resources in northwest china.– beijing: geological publishing house, 1–150. (in chinese). xiang, a.q., liang, j., chu, n., wang, r.j., lu, y. & liu, b.h. (2015): airborne hyper-spectral mineral mapping and prospecting prediction in the kalatage area, xinjiang.– mineral exploration, 6/5, 586–593. (in chinese with english abstract). xie, q., meng, q., zhang, l., wang, c. & sun, y. (2017): a soil moisture retrieval method based on typical polarization decomposition techniques for a maize field from full–polarization radarsat–2 data.– remote sensing. 9/2, 168. doi: 10.3390/rs9020168 xie, q., xu, f., wang, n. & yang, z. (2020): geological conditions and gasbearing evaluation of the niutitang formation shale in the xixiang–zhenba area, china.– geologia croatica, 73/1, 49–58. doi: 10.4154/gc.2020.05 yan, s.x., zhang, b., zhao, y.c., zheng, l.f., tong, q.x. & yang, k. (2004): summarizing the technical flow and main approaches for discrinination and mapg eo lo gi a c ro at ic a geologia croatica 74/182 ping of rocks and minerals using hyperspectral remote sensing.– remote sensing for land & resources, 19/1, 52–63. (in chinese with english abstract). yang, j.g., zhai, j.y., yang, h.w., wang, x.h., xie, c.l., wang, x.a. & ren, b.c. (2010): metallotectonics and prospection of the huaniushan exhalogene gold-silver-lead-zinc deposit in beishan, gansu province.– geotectonicaet metallogenia, 34/2, 246–254. (in chinese with english abstract). yang, q.h., wu, x.j., xiao, z.h., liu, x.j. & dong, m.x. (2015): technology research on mineral extraction by using casi/sasi airborne hyperspectral data.– journal of geomechanics, 21/2, 241–251. (in chinese with english abstract). ye, f.w., liu, d.c. & zhao, y.j. (2011): airborne hyper-spectral survey system casi/sasi and its preliminary application in uranium exploration.– world nuclear geoscience, 28/4, 231–236. (in chinese with english abstract). doi: 10.3969/j.issn.1672–0636.2011.04.008 yessy, a., miyatake, s., momose, a., anna, n., kombadayedu, m., aphary, m., minsozi, s. & ewereth, m. (2011): hyperspectral mapping for rock and alteration mineral with spectral angle mapping and neural network classification method: study case in warm bad district, south of namibia.– geoscience and remote sensing symposium (igarss), ieee, lnternational, 1752–1754. zhang, y.j., yang, j.m. & yao, f.j. (2007): the potential of multi-spectrel remote sensing techniques for mineral exploration-taking the mongolian oyu tolgoi co-au deposit as an example.– earth science frontiers, 14/5, 63–70. (in chinese with english abstract). zhang, z.c., zhang, x.j., hu, d.g., gao, w.l. (2011): application of hyperspectral remote sensing on mineral exploration in dongdatan district of east kunlun,qinghai province.– geoscience, 25/4, 760–767. (in chinese with english abstract). zhao, s.-h., zhang, f., wang, q., yao, y.-j., wang, z.-t. & you, d.-a. (2013): application of hyper-spectral remote sensing technology in environmental protection. – spectroscopy and spectral analysis, 33/12, 3343–3348. (in chinese with english abstract). doi: 10.3964/j.issn.1000–0593(2013)12–3343–06). zhao, x., wang, p., chen, c., jiang, t., yu, z. & guo, b. ((2017): water body information extraction from remote-sensing images after disasters based on spectral information and characteristic knowledge.– international journal of remote sensing, 38/5, 1404–1422. doi: 10.1080/01431161.2016.1278284 zhong, s., xu, c., yi, l. & li, y. (2018): focal mechanisms of the 2016 central italy earthquake sequence inferred from high-rate gps and broadband seismic waveforms.– remote sensing, 10/4, 512. doi: 10.3390/rs10040512 zhou, z.y. (2014): progress in hyperspectral remote sensing for petroleum prospecting.– remote sensing technology and application, 29/2, 252–261. (in chinese with english abstract). doi: 10.11873/j.issn.1004–0323.2014.2.0352 zhou, w., peng, b., shi, j., shi, j., wang, t., dhital, y.p., yao, r., yu, y., lei, z. & zhao, r. (2017): estimating high resolution daily air temperature based on remote sensing products and climate reanalysis datasets over glacierized basins: a case study in the langtang valley, nepal.– remote sensing. 9/9, 959. doi: 10.3390/rs9090959 g eologia c roatica fan et al.: application of an airborne hyper-spectral survey system casi/sasi in the gold-silver-lead-zinc ore district of huaniushan, gansu, china 83 plate 1. ironoxide outcrop of mineralized-alteration zones in the study area. a – limonite; b – hematite; c – jarosite and d – jarosite. g eologia c roatica 1. introduction the late palaeocene to early eocene interval is considered to be one of the warmest time periods (thomas, 1998) known as the palaeocene – eocene thermal maximum (petm) (kennett & stott, 1991) during which numerous events occurred. the remarkable climate change during that time can be explained by the release of a massive amount of methane from gas hydrates (dickens et al., 1995; katz et al., 1999). major changes in the terrestrial and marine biota occurred at the petm. this interval is marked by the mass extinction of benthic foraminifera, with a global decrease in their diversity, which ranges from 30 to 50% (kennett & stott, 1991), be­ ing known as the benthic foraminiferal extinction event (bfee) (thomas & shackleton, 1996). the time interval is cha­ racterized by the presence of short­ranging taxa such as „mal­ formed discoasters“ and „rhomboasters“. the extreme environmen­ tal changes at the petm caused those malformations of coccoliths (jiang & wise, 2006). the global palaeocene/eocene bound­ ary was defined at the dababiya quarry section, south of luxor, in the upper nile valley (dupuis et al., 2003). the aims of the present study are to identify the calcareous nannofossil assemblages of the petm interval, to assign the stu­ died sections to several nannofossil biozones and to provide some light on the palaeoecology for the late palaeocene­early eocene interval based on the presence of the most abundant calcareous nannofossil taxa. 2. geologic setting and lithostratigraphy the kharga oasis is one of the depressions of the western de­ sert, lying between latitudes 24o and 26o north, about 200 km to calcareous nannofossil bioevents at the palaeocene/eocene boundary in the kharga oasis, western desert of egypt mahmoud faris1, manal shabaan2 and fatma shaker3 1 tanta university, faculty of science, department of geology, tanta, egypt; (corresponding author: mhmfaris@yahoo.com) 2 kafr el sheikh university, faculty of science, department of geology, kafr el sheikh, egypt; (manalshabaan2010@yahoo.com) 3 benha university, faculty of science, department of geology, benha, egypt; (fatma_elkammar@hotmail.com, fatma.eldesouky@fsc.bu.edu.eg) doi: 10.4154/gc.2017.13 abstract two upper palaeocene – lower eocene stratigraphic sequences at the kharga oasis (umm el ghanayim and naqb assiut sections) were studied biostratigraphically on the basis of their calcareous nannofossil content. the investigated interval includes the upper part of the tarawan formation, the tarawan chalk, and the esna formations. a total number of sixty-seven different taxa have been identified. the lowest occurrence (lo) of discoaster araneus was used to place the base of the np9b subzone (base of eocene) at the gabal umm el ghanayim section. the lowest occurrences (los) of rhomboaster bitrifida, discoaster araneus and d. anartios are used to define the np9a/np9b subzonal boundary at the gabal naqb assiut section. in this section, the p/e boundary is marked by a minor lithologic hiatus as indicated by the absence of the basal part of the dababiya member. at the studied two sections, a major turnover in calcareous nannofossil assemblages across the p/e transition was documented. the abundance of warm water ericsonia subpertusa, fasculithus spp., coccolithus eopelagicus, discoaster spp., rhomboaster bitrifida and tribrachiatus bramlettei characterize the palaeocene-eocene transition and suggest global warming and the palaeocene – eocene thermal maximum (petm). the west of the nile valley. the two sections at kharga oasis are the naqb assiut and gabal umm el ghanayim sections were in­ vestigated (fig. 1). the upper palaeocene to lower eocene sedimentary suc­ cession in the kharga oasis includes from the base to the top: the upper part of the dakhla shale, the tarawan chalk, the esna shale and the thebes formations. the lithostratigraphic corre­ lation for the p/e rock units in different sections from the west­ ern and eastern desert and the present study, are illustrated in table 1. in the following paragraphs a brief description of the meas­ ured and sampled formations is given. 2.1. tarawan formation the tarawan formation was first termed by awad & gho­ brial (1965) to describe the limestone; chalky limestone and the marly limestone succession which overlie the dakhla shale and underlie the esna formation. this unit is about 11 m thick, and is represented by samples 1 to 8 in the gabal umm el gha­ nayim section. 2.2. esna formation the term esna shale was first introduced by beadnell (1905), to describe the shale succession that overlies the tarawan forma­ tion and underlies the thebes formation at gabal oweina, esna­ idfu area, upper nile valley. abdel­razik (1972) separated this formation into two members, the el hanadi member at the base and the el shaghab member at the top. dupuis et al. (2003) classified the esna formation from the base to the top, into three units (esna unit 1, esna unit 2 and esna unit 3) (table 1). article history: manuscript received april 06, 2017 revised manuscript accepted september 19, 2017 available online october 31, 2017 keywords: calcareous nannofossils, palaeocene/ eocene boundary, kharga oasis, western desert, egypt 2017 | 70/3 | 179–199 | 7 figs. | 6 tabs. | 2 pls. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society g eo lo gi a c ro at ic a geologia croatica 70/3180 figure 1. geological map of the kharga area (western desert, egypt) with the location of the studied sections (modified after said, 1990). aubry et al. (2007) subdivided the esna formation into four members, from the base to the top as follows, the el hanadi, el dababiya quarry, el mahmiya and abu had members. in the present study, the esna formation was sampled and described. the total thickness is about 17.5 m at the gabal umm el ghanayim section and about 10 m at the naqb assiut section. this rock unit represents the el-hanadi, el dababiya quarry and the lower part of el­mahmiya member (figs. 2 and 3). these members will be discussed briefly below. 2.2.1. el hanadi member the el hanadi member was originally introduced by abdel­ razik (1972) to describe the lower part of the esna formation (5 m of shale succession) which overlies the tarawan formation and underlies the el shaghab member at gabal el shaghab, east of el hanadi village, near esna city. according to aubry et al. (2007), the el hanadi member equates to the esna unit 1 of du­ puis et al. (2003). at the gabal umm el ghanayim section, the el hanadi member is composed of a calcareous shale about 1 m g eologia c roatica faris et al.: calcareous nannofossil bioevents at the palaeocene/eocene boundary in the kharga oasis, western desert of egypt 181 table 1. lithostratigraphic correlation for the p/e transition interval, between different works from the western and eastern desert and the present study. thick at the base (sample 9 to 11), and another shale of about 8 m thick (samples 12 to 26) at its top (fig. 2). at the naqb assiut sec­ tion, the lower part of the el hanadi member is composed of about 6 m of shale deposits (samples 1 to 17) and varies gradu­ ally into massive marls of about 0.95 m thick (samples 18 and 19) in its upper part. 2.2.2. dababiya quarry member at the type locality, the el dababiya quarry member consists of five characteristic beds (1-5) of about 3.68 m thickness: bed no. 1 is an organic rich clay layer (~0.63 m thick); bed no. 2 is a phos­ phate brown shale (~0.50 m thick); and bed no. 3 is a creamy phosphatic shale (~0.84 m thick); bed no. 4 is a grey calcareous shale (~07.1 m thick) and bed no. 5 is a calcarenitic marly lime­ stone (~1.00 m thick) (aubry et al., 2007). in the current study, the dababiya quarry member is about 1.2 m thick at gabal umm el ghanayim and 0.9 m thick at the naqb assiut section. this member consists of three beds as de­ scribed from the base to the top: bed 1 is an organic rich clay layer, which contains scattered coprolites at gabal umm el ghanayim (sample 27, about 15 cm), but it is absent at the naqb assiut sec­ tion; bed 2 is brown-coloured fish debris and coprolite-rich lami­ nated shale at gabal umm el ghanayim (samples 28 to 35, about 90 cm). at the naqb assiut section it consists of massive phos­ phatic marls rich with collophane grains at the base, and 70 cm of marly limestone at the top (samples 20 and 21, about 20 cm). bed 3 consists of marls at gabal umm el­ghanayim (sample 36, about 15 cm), while at the naqb assiut section (fig. 3) it is mainly com­ posed of chalky limestone (samples 22 to 25, about 70 cm). 2.2.3. el mahmiya member this member was defined by aubry et al. (2007), to cover the esna 2 unit of dupuis et al. (2003) at the village of el dababiya (35 km south of luxor). at the gabal umm el ghanayim section, the el mahmiya member is essentially composed of about 6 m of shale (samples 37 to 48), while at the naqb assiut section, the el mahmiya member consists mainly of 2.25 m of calcareous shale (samples 26 to 30). 3. material and methods a total number of 78 samples were collected for calcareous nan­ nofossils investigations, from which 48 belong to the gabal umm el ghanayim section and 30 to naqb assiut. the samples have been closely collected from the upper palaeocene­lower eocene interval in the study sections and reach about 5 cm near the p/e boundary. the calcareous nannofossil assemblages were observed using a polarized light microscope at a magnification of 1250x and their identification was based on the standard taxonomy of perch­nielsen (1985). calcareous nannofossil abundances were determined by counting 200­300 specimens/slide (backman & shakle­ ton, 1983). additionally, one random traverse of the slide was scanned for rarer species. the nannofossil relative abundance was considered as follows: a = abundant (>10 specimens/field of view), c = common (1-10 specimens/field of view), f = few (1 specimen/1-10 fields of view), r = rare (1 specimen/> 10 fields of view) vr= very rare (1 specimen/more than100 field of view). the species richness is given as the total number of species re­ corded in each sample. nannofossil preservation was classified as: g = good (little or no evidence of dissolution and/or overgrowth; specimens can be easily identified to species level) and m = moderate (speci­ mens exhibit some etching and/or overgrowth; most specimens are identifiable to the species level). g eo lo gi a c ro at ic a geologia croatica 70/3182 figure 2. lithostratigraphy and biostratigraphy of umm el ghanayim section (kharga oasis, western desert, egypt), samples position and correlation to the standard zonation of martini (1971). figure 3. lithostratigraphy and biostratigraphy of naqb assiut section (kharga oasis, western desert, egypt), samples position and correlation to the standard zonation of martini (1971). palaeotemperatures from calcareous nannofossil proxies were calculated using the microsoft excel program in accordance with the mentioned authors in the palaeoecologysection and our research data. the biostratigraphic zonation proposed by martini (1971) and okada & bukry (1980) was adopted. in addition, other bioevents for lower latitudes were also used (agnini et al., 2014). 4. results 4.1. calcareous nannofossils biostratigraphy the present manuscript concerns the biostratigraphy of calcare­ ous nannofossils from the upper part of the tarawan chalk and esna formations (upper palaeocene – lower eocene interval) at the umm el ghanayim and naqb assiut sections. the calcareous nannofossil assemblages are rich (72 species) and very diverse (22 genera) throughout the studied interval (late palaeocene to early eocene), while the preservation varies from moderate to good. the stratigraphic distribution charts of calcareous nannofos­ sil species are shown in figs. 4 and 5. some index calcareous nannofossil species are illustrated in pls. 1 and 2. abbreviations used in the present study are: np = palaeogene nannofossil zone of martini (1971), cp = palaeogene nanno­ fossil zone of okada & bukry (1980), cnp (palaeocene cal­ careous nannofossil zone) and cne (eocene calcareous nanno­ fossil zone) of agnini et al. (2014). their correlation is shown in table 2 with four nannofossil zones identified in the present study, covering the time interval from the late palaeocene to early g eologia c roatica faris et al.: calcareous nannofossil bioevents at the palaeocene/eocene boundary in the kharga oasis, western desert of egypt 183 eocene and occupying the top of the tarawan chalk and the esna shale formations. these biozones are briefly discussed below. 4.1.1. heliolithus kleinpellii zone (np6) definition: this zone comprises the interval from the lo of heliolithus kleinpellii to the lo of discoaster mohleri. authors: mohler & hay in hay et al. (1967) age: late palaeocene correlation: h. kleinpellii zone (cp5) of okada & bukry (1980). it is equivalent to the upper part of the h. cantabriae bz (cnp8) of agnini et al. (2014) (table 2). occurrence: this zone is represented by 1­5 samples, from the gabal umm el ghanayim section. it is not recorded at some localities in egypt (faris et al., 1999; faris & zahran, 2002). the h. kleinpellii zone is well represented in many other areas in egypt (strougo & faris, 1993; faris et al., 2000, 2005; ayyad et al., 2003; faris & abu shama, 2007a; faris & farouk, 2015a). remarks on assemblages: beside the marker species heliolithus kleinpellii (fig. 4), this zone includes coccolithus eopelagicus, ericsonia subpertusa, e. universa, toweius eminens and t. tovae. 4.1.2. discoaster mohleriheliolithus riedelii zone (np7-np8) definition: this zone is defined as the interval from the lo of discoaster mohleri to the lo of discoaster multiradiatus. author: hay (1964); emended by romein (1979). age: late palaeocene correlation: it is equivalent to the d. mohleri – d. nobilis (cp6­cp7) zones of okada & bukry (1980), to the discoaster mohleri (cnp9) and discoaster backmanii (cnp10) zones of agnini et al. (2014) (table 2). occurrence: at gabal umm el ghanayim, this zone is re­ stricted to within the top part of the tarawan formation (samples 6 and 7). discoaster mohleri/heliolithus riedelii zone was re­ corded in different areas in egypt (faris 1988a, b; strougo & faris, 1993; faris et al., 1999; ayyad et al., 2003; ghandour et al,. 2004; faris & abu shama, 2007a; faris & salem, 2007b). remarks on assemblages: the base of this zone is defined by the lo of d. mohleri whilst its top is defined by the lo of d. multiradiatus (abu shama et al., 2007; faris & abu shama, 2007a). the calcareous nannofossil assemblages are similar to those of the underlying np6 zone, with the additional presence of marker species d. mohleri (fig. 4). 4.1.3. discoaster multiradiatus zone (np9) definition: this zone defines the interval from the lo of discoaster multiradiatus to the lo of tribrachiatus bramlettei. authors: bramlette & sullivan (1961); amended by martini (1971) age: late palaeocene correlation: chiasmolithus bidens subzone (cp8a) of okada & bukry (1980). it is equivalent to the discoaster multiradiatus/fasciculithus richardii gr. crz (cnp11) of agnini et al. (2014) (table 2). occurrence: the np9 zone covers the topmost part of the tarawan formation (sample 8), as well as most of the esna for­ mation (samples 9 to 38) at the gabal umm el ghanayim section, and occupies the whole esna formation at the gabal naqb assiut section (samples 1 to 30). remarks on assemblages: the calcareous nannofossil as­ semblages are highly diverse and abundant in the np9 zone and this agrees well with the statement of perch­nielsen (1985) that the palaeocene diversity reached a maximum value in the table 2. late palaeocene to early eocene biozones and bioevents, according to the standard biozonations of martini, 1971 (np), okada & bukry, 1980 (cn), agnini et al., 2014 (cnp to cne) and the zonal scheme of the present study. http://www.sciencedirect.com/science/article/pii/s1464343x14001010#b0145 http://www.sciencedirect.com/science/article/pii/s1464343x14001010#b0280 g eo lo gi a c ro at ic a geologia croatica 70/3184 np9 zone. the identification of np9 is mainly based on the prese nce of d. multiradiatus. the marker species d. multiradiatus is continuously present from sample 8 upwards in g. umm el ghanayim and appears in all samples in the nabq assiut section. the genus fasciculithus suffered decreasing diversity at the onset of the p/e boundary, and disappeared completely shortly above the base of the np10 zone. aubry (1999) divided the np9 zone into two subzones (np9a and np9b) based on the lowest appearance of rhomboaster spp. and/or discoaster araneus. figure 4. stratigraphic distribution of calcareous nannofossil species in umm el ghanayim section, kharga oasis, western desert, egypt. g eologia c roatica faris et al.: calcareous nannofossil bioevents at the palaeocene/eocene boundary in the kharga oasis, western desert of egypt 185 the two subzones of aubry (1999) were identified in our study. the np9a/np9b is marked by the lo of discoaster araneus at the gabal umm el ghanayim section (fig. 4) and the los of rhomboaster bitrifida, discoaster araneus and d. anartios can be used to delineate the base of np9b at the gabal naqb assiut section (fig. 5). the total range of d. mahmoudii characterizes the subzone np9c (aubry & salem, 2012). in the umm el ghanayim sec­ tion, d. mahmoudii first appears in sample 37. the lo of r. spineus in sample 34, is restricted to np9c. we can conclude that the subzone np9c is approximately represented by a short inter­ val (samples 34­38) in this section. in the naqb assiut section, the los of d. araneus, d. anartios and r. bitrifida (markers of np9b) occur in sample 20. nevertheless, d. mahmoudii appears only in sample 27 and the base of the np9c can also be tentatively placed at this sample. figure 5. stratigraphic distribution of calcareous nannofossil species in naqb assiut section, kharga oasis, western desert, egypt. g eo lo gi a c ro at ic a geologia croatica 70/3186 4.1.4. tribrachiatus contortus zone (np10) definition: this biostratigraphic interval is defined by the lo of tribrachiatus bramlettei or discoaster diastypus at its base and the ho of t. contortus at its top. authors: hay (1964) age: early eocene correlation: subzones campylosphaera eodela (cp8b) and tribrachiatus contortus (cp9a) of okada & bukry (1980). it is equivalent to fasciculithus tympaniformis tz (cne1), to toweius eminens prz (cne2) and to the lowermost part of tribrachiatus orthostylus bz (cne3) of agnini et al. (2014) (table 2). occurrence: at the gabal umm el ghanayim section, t. bramlettei has rare occurrences and the top of the zone cannot be defined due to the complete absence of tribrachiatus contortus. remarks on assemblages: a new species, tribrachiatus digitalis, was described from the dsdp site 550, and used to sub­ divide the np10 zone into four subzones (aubry, 1996). the lo of t. bramlettei defines the base of the np10a subzone, the lo of t. digitalis defines the base of the np10b subzone, the ho of t. digitalis defines the base of the np10c subzone, and the lo of t. contortus defines the base of the np10d subzone. the base of the np11 zone (= top of np10d subzone) is defined by the ho of t. contortus. aubry et al. (1999) also used this subdivision in their de­ scription of the esna shale of egypt (gebel qreiya, gebel kila­ biya). dupuis et al. (2003) used the same four nannofossil sub­ zones for dividing the np10 of martini (1971) at the dababiya section. only the subzones np10a and np10b have been identified at the gabal umm el ghanayim section. in the umm el ghanayim section, the np10a subzone includes the interval from sample 39 to 40. the interval from samples 41 to 48 can be assigned to the np10b subzone, based on the observed first rare occurrence of t. digitalis. 5. discussion 5.1. palaeocene/eocene (p/e) boundary the onset of the carbon isotopic excursion (cie) associated with the palaeocene/eocene thermal maximum (petm) is considered as a best criterion for defining the p/e boundary in marine and non­marine sequences worldwide. table 3. calcareous nannofossil bioevents at the palaeocene/eocene boundary recorded by different authors in the eastern and western desert and nile valley. sections authors location p/e boundary calcareous nannofossil bioevents taramsa youssef (2016) west qena np9a/np9b los of d. araneus, d. anartios, d. aegyptiacus, rhomboaster spp., ca. eodela/dela duwi quseir qeryia wadi qena arras safaga darb gaga-1 faris & abdel sabour (a; b; c) (in prep) southern kharga oasis np9a/np9b los of d. araneus, d. anartios, r. intermedia darb gaga-2 np9a/np9b los of d. araneus, d. anartios, r. bitrifida al aguz area northern kharga oasis np9a/np9b los of r. calcitrapa, r. spineus, d. araneus, d. anartios nag el-quda youssef (2015) eastern desert np9a/np9b lad of d. araneus and rhomboaster spp. gebel ghanima khalil & al sawy (2014) kharga oasis np9a/np9b lo of r. cuspis abrupt decrease of fasciculithus spp. el serai tantawy (2006) east qena np9a/np9b los of ca. eodela/dela, d. araneus abrupt decrease of fasciculithus spp.taramsa west qena geirya (abu had) aubry (1999) east qena np9a/np9b los of d. araneus, r. spineus, r. cuspis, d.araneuskilabiya nile valley np9a/np9b teir/tarawan faris et al. (1999) kharga oasis within np9 hos of fasciculithus spp. um el-ghanayim los of t. bramlettei, d. binodosus el sheikh eissa east qena hos of fasciculithus spp. ei-homra el-shanka esna np9/np10 lo of t. bramlettei g. el-shaghab lo of t. bramlettei north gunna faris & strougo (1998) nile valley np9/np10 hos of f. tympaniformis, f. bobii, f. clinatus, f. clinatus, f. involutus, d. mediosus el sheikh marzouk np9/np10 duwi tantawy (1998) quseir np9a/np9b lo of ca. eodela/dela oweina nile valley np9a/np9b abu had ne desert np9a/np9b wadi tarfa east qena np9a/np9b wadi el dakhl strougo & faris (1993) southern galala plateau np9/np10 lo of t. bramlettei abu had faris et al. (1989) qena region np9/np10 lo of d.mahmoudii hos of f.alanii, f. bobii, d. mohleri, d. falcatus, f. tympaniformis ei serai top np9 tarmsa top np9 wasif area hewaidy & faris (1989) safaga district np9/np10 los of t. nunnii, d. diastypus ho of f. tympaniformis um el huetat faris (1988b) np9/np10 hos of f. alanii, f.tonii, f. tympaniformis lo= lowest occurrence; ho= highest occurrence; ha= highest appearance; lad= lowest appearance datum g eologia c roatica faris et al.: calcareous nannofossil bioevents at the palaeocene/eocene boundary in the kharga oasis, western desert of egypt 187 at the dababiya section (the global standard stratotype sec­ tion and point – gssp) the base of the lower eocene beds (73 cm thick) is carbonate free and barren of calcareous nannofossils, and the taxa discoaster araneus, discoaster anartios, rhomboaster spineus, and rhomboaster spp. were recorded directly above this barren interval (dupuis et al., 2003). el dawy et al. (2016) studied the planktonic foraminifera at the naqb assiut section. they observed an irregular uncon­ formity surface associated with pebbles and bioturbated sand at the palaeocene/eocene boundary interval, and they suggested the existence of a minor hiatus at this boundary. in the present study, this small hiatus cannot be detected by means of nannofossils. at the wadi nukhul section, west central sinai, khozyem et al. (2013), suggest that the lowermost eocene sediments are absent. the presence of a short hiatus at the p/e boundary is also observed in other sections from egypt (gabal duwi and g. aweina sections; speijer et al., 2000). the presence of a hiatus at the p/e boundary was recorded at the w. nukhul, wadi matu­ lla, and g. mekattub sections (west central sinai) (faris et al., 2015b). at the gabal umm el ghanayim section, the lo of discoaster araneus was used to delineate the base of subzone np9b, while the los of rhomboaster bitrifida, discoaster araneus and d. anartios can be used for approximation of the np9a/np9b subzonal boundary (early eocene) at gabal naqb assiut section. 5.2. calcareous nannofossil bioevents fasciculithus alanii occurs below the p/e boundary, and is re­ stricted to the np9a subzone (dupuis et al., 2003). the ho of this species has also been reported in several areas in egypt such as gabal aweina, gabal duwi, gabal abu had (aubry, 1998; von salis et al., 1998; aubry & salem, 2013) and at wadi nukhul in west central sinai (khozyem et al., 2013). the ho of f. alanii at the markha section (wc sinai), can be used to ap­ proximate the p/e boundary (faris & farouk, 2015). in the present study, the ho of fasciculithus alanii was recorded at the base of the np9b subzone (sample 27) at the gabal umm el gha­ nayim section. the first occurrence of discoaster mahmoudii is noticed in the uppermost part of the np9b subzone in the investigated sec­ tions (figs. 4, 5), and has its last appearance (ho in sample 39) in the lower part of the np10a subzone at the gabal umm el ghanayim section. the lowest occurrence of campylosphaera eodela is within the np9a subzone (late palaeocene) at the gabal umm el gha­ nayim section, indicating that this species cannot be used as a reliable marker for subdividing the cp8 (=np9) of okada & bukry (1980) into cp8a and cp8b (=np9a and np9b). the cal­ careous nannofossil bioevents, recorded by different authors in many sections in egypt, are summarized in tables 3 and 4. 5.3. calcareous nannofossil turnover the calcareous nannofossil assemblages displayed turnover at the p/e boundary transition (figs. 4, 5). several species became extinct, others continued into the eocene and some new taxa ap­ peared in the eocene. some fasciculithus (fasciculithus tonii, f. richardii, f. schaubii. f. thomasii, f. clinatus, f. lillianiae) and discoaster species (d. mediosus, d. mohleri) disappeared within the np9a subzone. the coccoliths that survived include campylosphaera eodela, discoaster lenticularis, d. multiradiatus, fasciculithus tympaniformis, f. involutus and zygrhablithus bijugatus. table 4. calcareous nannofossil bioevents at the palaeocene/eocene boundary recorded by different authors in sinai. sections authors location p/e boundary calcareous nannofossil bioevents abu zenima bolle et al. (2000) western sinai wihin np9 c. pelagicus acme bir faris et al. (2005) w es t c en tr al si na i np9a/np9b ha of fasciculithus spp. el markha faris & farouk (2015) np9a/np9b co. bownii acme los of r. bitrifida, r. intermedia ho of f. alanii matulla abu shama et al. (2007) np9a/np9b los of r. cuspis, r. calcitrapa, d. mahmoudii, d. araneus bolle et al. (2000) wihin np9 los of d. araneus, r. bitrifida, r. intermedia faris et al. (2015) np9a/np10 lo of t. bramlettei faris & farouk (2015) np9a/np9b lo of r. intermedia nukhul faris & salem (2007) ea st c en tr al si na i np9a/np9b los of r. intermedia, r. calcitrapa khozyem et al. (2013) np9a/np9b los ca. eodela/dela, r. cuspis faris et al. (2015) np9a/np10 los of t. bramlettei, d. anartios, d. araneus, r. bitrifida, r. cuspis, r. intermedia, r. spineus mukattab faris et al. ( 2015) w es t c en tr al si na i np9a/np10 los t. bramlettei, d. anartios, d. araneus, r. bitrifida, r. cuspis, r. intermedia, r. spineus wadi feiran faris & salem ( 2007) np9a/np9b lo of r. solus faris et al. (2015) np9a/np10 los t. bramlettei, d. anartios, d. araneus, r. bitrifida, r. cuspis, r. intermedia, r. spineus el mishiti faris & abu shama (2007) ec sinai np9/np10 los of r. cuspis, r. calcitrapa, d. mahmoudii, d. araneus muwaylih ayyad et al. (2003) ne sinai np9a/np9b ho of f. alanii amr el burk area faris & zahran (2002) nc sinai np9/np10 lo of t. bramlettei el sheikh attya luning et al. (1998) ec sinai np9/np10 los of d. diastypus, d. binodosus hoof f. tympaniformis el ain faris (1988a) ne sinai np9/np10 los of t. contortus, d. diastypus, d. mahmoudiiel falig g eo lo gi a c ro at ic a geologia croatica 70/3188 figure 6. vertical variations in the number of warm water and cold water species in umm el ghanayim and naqb assiut sections. the eocene assemblage includes rhomboaster taxa (r. intermedia, r. bitrifida, r. cuspis, and r. spineus) in addition to the first appearances of discoaster araneus, d. anartios, d. paelikei, and d. mahmoudii which occurred within the np9b subzone (early eocene). in the present study, the rhomboaster-discoaster taxa did not occur simultaneously, having very rare relative abundances (figs. 4, 5). the first appearance of d. araneus is at the base of np9b at the um el ghanayim section. other taxa occurred in sequential order: d. anartios, r. bitrifida, r. cuspis and r. spineus. at the gabal naqb assiut section, d. araneus, d. anartios and r. bitrifida co­occurred at the base of the np9b subzone, and r. cuspis appeared later at a higher level within np9b. 5.4. diversity the diversity of calcareous nannofossils is the number of species in each sample. it reaches its maximum in the late palaeocene (perch­nielsen, 1985; faris & salem, 2007). the cal­ careous nannofossil diversity reaches a maximum of 26 species in the np9a subzone (sample no. 17), with 21 species in np9b at g. umm el ghanayim section. above this subzone, fluctuations in species diversity occur, with variations from 24 to 7 species in the np10 zone with a generally decreasing trend. at the naqb assiut section, the number of species fluctuates within np9a from 5 to a maximum of 23 species (sample no 6), and reaches about 16 species in the upper part of late palaeocene, while above that level the diversity fluctuates from 7 to 18 spe­ cies in the np9b subzone (early eocene). the fasciculithus diversity decreases sharply within the np9b subzone and it disappears completely shortly in the low­ ermost part of np10 (fig. 4). in the basal part of zone np10, f. tympaniformis and f. involutus were recorded. the same obser­ vations were recorded in the qreiya, duwi and oweina sections (von salis et al., 1998), in g. taramsa, g. serai (tantawy, 2006) and in the gabal qreiya, gabal arras, and gabal duwi sections (youssef, 2009, 2015, 2016). 5.5. palaeoecology several authors have proposed a link between some nannofossil species abundance and oceanographic changes that may have oc­ curred during the petm (e.g. bralower, 2002; kahn & aubry, 2004; tremolada & bralower, 2004; gibbs et al., 2006 a, b; jiang & wise, 2006). several nannofossil taxa are known to be adapted to warmer, more oligotrophic surface water environments. the genus discoaster has often been asso­ ciated with warm water species (edwards, 1968; bukry, 1973), while aubry (1992) proposed that this genus was also adapted to oligotrophic conditions. the genera fasciculithus and sphenolithus were adapted to warmer, more oligotrophic envi­ ronments, as noted in different odp sites (bralower, 2002; gibbs et al., 2006a, b). taxa belonging to the rhomboaster­tribrachiatus lineage have been regarded as proxies for warm­wa­ ters and oligotrophic conditions (aubry, 1998; bralower, 2002; tantawy, 2006; mutterlose et al., 2007). coccolithus pelagicus is a dominant species of the high lati­ tudes from the neogene to the present, based on palaeobiogeo­ g eologia c roatica faris et al.: calcareous nannofossil bioevents at the palaeocene/eocene boundary in the kharga oasis, western desert of egypt 189 graphic studies (mcintyre & be, 1967, haq & lohmann, 1976, haq, 1980). in addition, c. pelagicus s. ampl. prevails in lower latitudes during mid­palaeocene to early eocene, where c. eopelagicus is documented in the early eocene (haq & lohm­ ann, 1976) as in this study as characterizing global warming and early eocene climatic optimum. nevertheless, coccolithus pelagicus dominates in the low latitudes throughout late palaeocene­ early eocene time, indicating nutrient improvement (jiang & wise, 2006), which could also be the cause of our results too. coccolithus pelagicus s. ampl. dominates in assemblages together with ericsonia subpertusa in our sections too. an increase of the relative abundance of coccolithus pelagicus and ercisonia subpertusa (c. subpertusus) during the petm in the studied two sec­ tions was observed. they are interpreted as indicators of warm waters and were presumably adapted to oligotrophic environment based on their close association with the excursion taxa (discoast­ ers, rhomboasters, tribrachiatus). it is evident that changes in the abundance of the calcareous nannofossil species can be inter­ preted as a response to palaeoecologic conditions such as palaeo­ temperature and nutrients. the acme of ericsonia subpertusa (coccolithus subpertusus) was recorded at the dababyia section above the dissolution horizon with the los of d. anartios and rhomboasters (base of np9b) and coincides with the negative δ13c value of the cie (dupuis et al., 2003), which proves the aforementioned benthic foraminiferal extinction event (bfee). these authors correlated this acme with that recorded at the equa­ torial pacific ocean drilling site 865 (kelly et al. 1996) and concluded that the acme of e. subpertusa is a global acme pos­ sibly as a response to global warming. e. subpertusa (c. subpertusus) is common in the lower part of petm, then reaches its acme in the middle part of the petm in the matulla section (west cen­ tral sinai (abu shama et al., 2007) and coincides with the lo of rhomboaster taxa. in the studied two sections, the relative abundance of e. subpertusa varies from frequent to common in­ dicating warming conditions and eutrophication that occurred around the palaeocene/eocene boundary. the lower abundances of early eocene oligotrophic, warm water rhomboaster species are possible consequences of the aforementioned nutrient­richer water condition. this is also evident from the domination of eu­ trophic, warm water c. eopelagicus detected in the early eocene at the um el ghanayim section. today, large forms of c. pelagicus can be observed at lower latitudes and upwelling regions (ziveri et al., 2004, baumann et al., 2000). in the studied sections, semi­quantitative analyses of calcar­ eous nannofossil assemblages were performed for the interval from np7­8 to the basal part of the np10 zone. at the um el ghanayim section, the number of warm water nannofossil taxa fluctuates between 6-17 species in the late palaeocene (np7-8 figure 7. total warm and cold water specimens/slide and warm/cold water specimens in umm el ghanayim and naqb assiut sections. g eo lo gi a c ro at ic a geologia croatica 70/3190 table 5. calcareous nannofossils from umm el ghanayim section, grouped according to their paleoecological behaviour into warm water, cold water and non-characteristic species. ag e fo rm at io n sa m pl e n o. n an no fo ss il zo ne (n p) warm water co cc ol ith us p el ag icu s co cc ol ith us eo pe la gi cu s er ic so ni a su bp er tu sa sp he no lit hu s p rim us th or ac os ph ae ra o pe rc ul at a he lio lit hu s k le in pe lli i* d isc oa st er m oh le ri* fa sc icu lit hu s c lin at us fa sc icu lit hu s t ym pa ni fo rm is* fa sc icu lit hu s i nv ol ut us d isc oa st er le nt icu la ris po nt os ph ae ra ve rs a d isc oa st er m ul tir ad ia tu s* zy gr ha bl ith us b iju ga tu s fa sc icu lit hu s a la ni i d isc oa st er fa lca tu s fa sc icu lit hu s t on ii fa sc icu lit hu s s ch au bi i fa sc icu lit hu s l ili an ia e d isc oa st er b in od os us fa sc icu lit hu s b ob ii po nt os ph ae ra o ce lla ta th or ac os ph ae ra sa xe a fa sc icu lit hu s r ich ar di i fa sc icu lit hu s t ho m as ii br aa ru do sp ha er a bi ge lo w ii d isc oa st er m ed io su s d isc oa st er a na rt io s* rh om bo as te r c us pi s* rh om bo as te r s pi ne us * d isc oa st er p ae lik ei ea rly e oc en e es na s ha le el m ah m iy a m b. 48 n p1 0b x   x   x               x x                 x     x           47 x   x x                 x                   x     x           46 x   x   x               x x                                   45 x   x   x               x                         x           44 x x x x                 x                         x           43 x   x   x               x                                     42 x x x   x                                   x     x         x 41 x   x x x               x x               x x     x           40 n p1 0a x x x x x       x x     x x                       x         x 39 x x x x x       x x     x x           x   x       x     x     38 n p9 b x     x x       x       x                         x     x     37 x   x x x       x x     x x               x       x           d ab ab iy a q ua rr y m b. 36 x x x x x         x       x                       x   x x   x 35 x   x x                   x             x   x         x x   x 34 x   x x                 x                   x         x   x   33 x x x x                 x x                           x       32 x   x           x   x   x x                 x         x       31 x x x x         x   x     x                 x         x       30 x   x x                 x x               x x                 29 x x x x         x       x x                 x                 28 x x x x             x   x x   x           x x                 27 x x x                   x   x                                 la te p al ae oc en e el h am di m em be r 26 n p9 a x x x x                 x   x             x                   25 x x x x           x     x x               x x                 24 x   x x x     x x x x   x   x             x     x x x         23 x   x x x     x   x x   x x               x                   22 x x x x x     x x x     x     x         x x   x x             21 x   x x x     x x x     x   x x   x       x                   20 x x x x x     x x x     x x x x           x x       x         19 x   x x x     x x x x   x   x x   x       x     x             18 x   x x x     x     x   x x   x   x       x     x x x         17 x x x x x     x x x   x x x x x   x       x   x x             16 x   x x       x x x x x x x x x           x x x x   x         15 x     x x     x x x     x x       x x   x x                   14 x x x x x     x x x x   x x x x   x x   x                     13 x   x   x       x x x   x x x     x x x x                     12 x x x x x x   x x x x x x     x                               11 x   x x x x   x x x x   x x x x x                             10 x   x x x x   x x x x   x x x                                 9 x x x x x     x x x x x x x                                   ta ra w an 8 x   x x x     x x x x x x                                     7 n p7 n p8 x x x x x x x   x x                                           6 x x x x x   x x x x                                           g eologia c roatica faris et al.: calcareous nannofossil bioevents at the palaeocene/eocene boundary in the kharga oasis, western desert of egypt 191 cold water non-characteristic po nt os ph ae ra p la na d isc oa st er a ra ne us * rh om bo as te r b itr ifi da * d isc oa st er m ah m ou di i* tr ib ra ch ia tu s b ra m le tte i* sp he no lit hu s m or ifo rm is d isc oa st er b ar ba di en sis d isc oa st er b ac km an ii tr ib ra ch ia tu s d ig ita lis * d isc oa st er d ia st yp us po nt os ph ae ra ex ili s sp ec ie s r ic hn es s to w ei us to va e to w ei us em in en s ne oc hi as to zy gu s j un ct us ne oc oc co lit he s p ro te nu s ch ia sm ol ith us d an icu s ch ia sm ol ith us ca lif or ni cu s ch ia sm ol ith us co ns ue tu s ch ia sm ol ith us b id en s ch ia sm ol ith us so lit us ch ia sm ol ith us eo gr an di s sp ec ie s r ic hn es s er ic so ni a un iv er sa el lip so lit hu s m ac el lu s* zy go di sc us p le ct op on s zy go di sc us a da m as ca m py lo sp ha er a eo de la ne oc hi as to zy gu s p er fe ct us ca lci so le ni a ap er ta "e lli ps ol ith us b ol lii el lip so lit hu s d ist ich us er ic so ni a ro bu st a to w ei us p er tu su s to w ei us o cc ul ta tu s zy go di sc us sh el do ni ae m icr an th ol ith us a tte nu at us ne oc hi as to zy gu s c hi as tu s sp ec ie s r ic hn es s x                   x 9     x           x   2 x 1 x                   x 8                     0 x 1 x                   x 7     x               1 x x 2 x                   x 7 x   x           x   3 x x 2 x       x         x   9     x               1 x x 2 x                 x   6     x               1 0 x           x     x   10     x               1 x 1 x           x   x     12     x               1 x x x 3 x       x     x       14     x               1 x x 2 x     x x x x         18   x x       x x     4 x x 2     x                 8     x               1 x x x 3 x     x               12     x               1 x x x x x x 6   x x                 13   x x               2 x x x x x x 6   x x                 11   x                 1 x x 2   x                   8     x               1 x x 2   x                   8     x               1 x x 2                       8     x               1 x x x 3                       9     x               1 x x 2                       7                     0 x 1 x x                   10     x               1 x x 2 x x                   12     x               1 x 1 x x                   7     x     x         2 x x 2                       7     x         x     2 x 1                       9   x x         x     3 x x x x x x 6                       14 x x x     x         4 x x x 3                       10     x     x         2 x x x x x x 6                       14     x       x       2 x x x x x x 6                       12             x x     2 x x x x 4                       15 x     x x     x     4 x x x x x x x 7                       14 x     x     x x     4 x x x x x x x x 8                       14             x x     2 x x x x x x 6                       17 x x         x x     4 x x x x x 5                       17 x             x     2 x x x x x x x x 8                       12 x x           x     3 x x 2                       16 x     x     x x   x 5 x x x x 4                       13 x x       x   x     4 x x x x 4                       13               x     1 x x x x x x 6                       14 x x         x x     4 x x x x x x 6                       12 x     x     x       3 x x x x x x x 7                       12 x x   x     x       4 x x x x x x x x 8                       10 x x   x   x         4 x x x x x 5                       9 x x     x           3 x x x x 4                       9 x   x   x           3 x 1 table 5. continued g eo lo gi a c ro at ic a geologia croatica 70/3192 table 6. calcareous nannofossils from naqb assiut section, grouped according to their paleoecological behaviour into warm water, cold water and non-characteristic species age formation sample no. nannofossil zone (np) w arm w ater cold w ater n on-characteristic coccolithus pelagicus coccolithus eopelagicus ericsonia subpertusa zygrhablithus bijugatus thoracosphaera operculata sphenolithus primus discoaster multiradiatus* discoaster lenticularis fasciculithus tympaniformis* fasciculithus schaubii fasciculithus bobii fasciculithus involutus braarudosphaera bigelowii discoaster mohleri * fasciculithus richardii fasciculithus clinatus discoaster falcatus thoracosphaera saxea pontosphaera exilis pontoshphera pulchra bomolithus megastypus pontosphaera formosa pontosphaera ocellata pontosphaera plana discoaster backmanii discoaster araneus* rhomboaster bitrifida* discoaster anartios* discoaster paelikei rhomboaster cuspis* pontosphaera multipora discoaster mahmoudii* species richness toweius tovae toweius eminens chiasmolithus bidens chiasmolithus consuetus neochiastozygus junctus neococcolithes protenus species richness toweius pertusus zygolithus sheldoniae campylosphaera eodela zygodiscus plectopons calcisolenia aperta ellipsolithus macellus* ellipsolithus distichus zygodiscus adamas ericsonia robusta lophodolithus nascens ericsonia universa species richness early eocene esna shale el mahmiya mb. 30 np9b x   x           x     x                                   x x   6       x x   2     x     x           2 29 x   x x x x x   x     x                                   x     9             0       x   x           2 28 x x x     x x   x     x                                         7       x     1           x           1 27 x   x x   x x         x x                   x             x x x 11       x x   2   x x x   x           4 26 x x x       x   x                                               5         x   1     x                 1 dqm 25 x   x     x x   x                                               5         x   1     x     x           2 24 x   x     x x                                                   4   x   x     2     x     x           2 23 x x x x x x x         x                                         8             0   x       x       x   3 22 x   x x x x x   x     x       x                   x x   x       12         x x 2                       0 21 x x x x   x                       x                             6         x   1       x x       x   x 4 20 x x x   x   x x       x                           x x x         10             0   x x x       x x x x 7 late palaeocene el hanadi member 19 np9a x x x   x x x x x                                               8       x x   2   x x x x x           5 18 x   x     x                                                     3             0     x             x   2 17 x x x   x x x x   x   x       x             x x x               13         x x 2     x   x             2 16 x   x     x     x     x x             x   x                     8 x x     x   3   x   x   x x x       5 15 x x x x x x x x x x   x x                 x                     13 x     x     2       x x x x x       5 14 x   x   x x x     x   x       x                                 8   x   x   x 3           x x x       3 13 x   x x x       x x   x               x     x                   9             0   x x x   x           4 12 x x x x x x x x     x x x   x x     x x   x                     16       x     1   x x x     x         4 11 x   x x x x x x   x   x x               x                       11       x     1   x x x   x   x       5 10 x x x x x x     x x   x             x                           10             0   x x x x       x     5 9 x   x     x x x x x   x x   x x     x                           12     x x x   3     x x     x x       4 8 x   x x x x x       x x x   x                                   10   x         1   x   x x     x       4 7 x x x x x x     x x   x     x x x                               12     x x     2   x x x x x   x       6 6 x   x x x x x x x   x x       x x x     x                       14 x   x       2   x x x x   x x       6 5 x   x x x x x x x x x x x x x                                   14     x       1   x x x x x x         6 4 x   x x x x x x x x x                                           10 x           1                       0 3 x x x x x x x x x x x x                                         12 x x         2   x x x x             4 2 x x x x x x x   x                                               8             0   x                   1 1 x x x x x x x x x x x x                                         12 x           1   x                   1 g eologia c roatica faris et al.: calcareous nannofossil bioevents at the palaeocene/eocene boundary in the kharga oasis, western desert of egypt 193 zone to np9a subzone) and reaches a maximum in a single sam­ ple of 12 species in the np9b of the early eocene, while the cold water taxa gradually decreases around this boundary (table 5). at the naqb assiut section, the warm water species range from 7 to 15 in number below the p/e boundary and decreases to 3 near this boundary. nevertheless, warm­water coccolithus eopelagicus, discoaster multiradiatus, d. araneus, ericsonia subpertrusa, sphenolithus primus, zygrhablithus bijugatus in conjunc­ tion to cold water neochiastozygus junctus are the most common species of the late palaeocene – early eocene interval in the two studied sections. this suggests the palaeocene–eocene thermal maximum (petm) with the pick in the samples 21 and 33 of the naqb assiut and umm el ghanayim sections respectively dur­ ing this time interval (figs. 6,7). the warm, cold water and non­characteristic calcareous nan­ nofossils near the p/e boundary at the umm el ghanayim and naqb assiut sections are shown in tables 5 and 6. the vertical variations in the number of warm water and cold water species in these two sections are shown in fig. 6. on the other hand, the total warm and cold water specimens/slide and warm/cold water specimens are shown in fig. 7. the last abundant appearance of coccolithus subpertusus, and the frequent occurrence of excursion taxa including discoaster araneus, d. anartios with rare rhomboaster spp. across the petm in four outcrops in central egypt are present in re­ sponse to the beginning of the warming period (youssef, 2016). 6. conclusions two upper palaeocene – lower eocene stratigraphic sequences at kharga oasis (the umm el ghanayim and naqb assiut sections) were studied biostratigraphically for their calcareous nannofossil content. the investigated interval comprises the upper part of the tarawan and the esna formations. the esna shale can be divided from the base to top as follows: the el hanadi, the dababiya quarry and el mahmiya members. at the umm el ghanayim section, the dababiya quarry member consists of three beds: an organic rich­clay layer (15 cm), brown-coloured fish debris and coprolite-rich laminated shale (90 cm) and marls (15 cm). at the naqb assiut section, the dababiya quarry member is composed of 20 cm of massive phosphatic marls rich with collophane grains at the base and 70 cm of marly limestone at the top. at the naqb assiut section, the p/e bound­ ary interval is marked by the absence of the organic rich­clay layer (bed no.1) of the dababiya quarry member at the dababiya section (gssp) which may indicate the presence of a minor hia­ tus at the base of the eocene. this minor unconformity could not be detected palaeontologically by means of nannofossils. at the gabal umm el ghanayim section, the exposed part of the tarawan chalk encompasses nannofossil zones np6, np7/8 and the basal part of the np9a subzone. the el hanadi member includes the middle and upper parts of the np9a sub­ zone, and this means that a conformable relationship exists be­ tween these two units. in this section, the dababiya quarry mem­ ber includes the np9b subzone (early eocene) and the el mahmiya member includes the upper np9b, the np10aand np10b subzones. the base of the np9b subzone is delineated by the lo of discoaster araneus at the g. umm el ghanayim section, while at the gabal naqb assiut section, the first appearances of the nannofos­ sil taxa rhomboaster bitrifida, discoaster araneus and d. anartios can be used to place the np9a/np9b subzonal boundary. the current study indicates that the umm el ghanayim sec­ tion appears to be stratigraphically complete, at least based on nannofossil biostratigraphic resolution, and spans a late palae­ ocene – early eocene time interval encompassing zones np9 to the base of np10. the palaeocene–eocene boundary is placed at the base of the dababiya quarry member of the esna fomation. several nannofossil species became extinct in the upper part of the np9a subzone (late palaeocene): fasciculithus tonii, f. richardii, f. schaubii, f. thomasii, f. clinatus, f. lillianiae, discoaster mediosus and d. mohleri. other taxa which crossed the p/e boundary include: campylosphaera eodela, discoaster lenticularis, d. multiradiatus, fasciculithus tympaniformis, f. involutus and zygrhablithus bijugatus. the excursion taxa (rhomboaster intermedia, r. bitrifida, r. cuspis, r. spineus, discoaster araneus, d.anartios) in addition to d. paelikei and d. mahmoudii have their first occurrences within np9b subzone. on the other hand, the species richness (diversity) fluctuates with a detected minimum around the palaeocene/eocene boun­ dary and fasciculithus spp. decreases in diversity and abundance above the palaeocene/eocene boundary in the studied sections which is in agreement with other aforementioned research in the region and globally. acknowledgement the authors wish to express their deep thanks to ines galović and an anonymous reviewer for their insightful reviews, their suggestions and valuable comments on this manuscript. references abdel­razik, t.m. (1972): comparative studies on the upper cretaceous–early pa­ laeogene sediments on the red sea coast, nile valley and western desert, egypt.– proceedings of the 8th arab petroleum congress, 71(b­3), 1023, algier. abu shama, a.m., faris, m. & al­wosabi, kh.a. (2007): upper palaeocene­ lower eocene calcareous nannofossil biostratigraphy and palaeoecology of gebel matulla section, south­western sinai, egypt proc.– the 5thinternational confe rence of the geology of africa, assiut, egypt, 1, 33–51. agnini, c., fornaciari, e., raffi, i., catanzariti, r., palike, h., back­ man, i. & rio, d. (2014): biozonation and biochronology of palaeogene calcare­ ous nannofossils from low and middle latitudes.– newsletters on stratigraphy, 47/2, 131–181. aubry, m­p. (1992): late palaeogene nannoplankton evolution: a tale of climatic de­ terioration.– in: prothero, d.r. & berggren, w.a. (eds.): eocene–oli­ gocene climatic and biotic evolution. princeton univ. press, princeton, nj, 272–309. aubry, m­p. (1996): towards an upper palaeocene–lower eocene high resolution stratigraphy based on calcareous nannofossil stratigraphy.– isr. j. earth­sci., 44, 239–253. aubry, m­p. (1998): late palaeocene­early eocene climatic and biotic events in the marine and terrestrial records.– in: aubry, m­p., lucas, sg. & berggren, w.a. (eds.), columbia univ. press, 158–203. aubry, m­p. (1999): late palaeocene–early eocene sedimentary history in western cuba: implications for the lptm and for regional tectonic history.– micropaleon­ tology, 45, 5–18. aubry, m.­p., berggren, w., cramer, b., dupuis, c., kent, d., ouda, kh., schmitz, b. & steurbaut, e. (1999): palaeocene/eocene boundary sections in egypt.– in: ouda, k.h. & soliman, h. (eds.): late palaeocene­early eocene events from northern africa to the middle east. international symposium in connection with first international conference on the geology of africa, nov. 23–25. aubry, m­p., ouda, k., dupuis, c., berggren, w.a., van couvering, j.a. & the members of the working group on the palaeocene/eocene boundary (2007): the global standard stratotype­section and point (gssp) for the base of the eocene series in the dababiya section (egypt).– episodes, 30/4, 271–286. aubry, m.p. & salem, r. (2013): the dababiya core: a window into palaeocene to early eocene depositional history in egypt based on coccolith stratigraphy.– stratigraphy, 9/3–4, 287–346. awad, g.h. & ghobrial, m.g. (1965): zonal stratigraphy of the kharga oasis. ministry of industry, general egyptian organization for geological research and mining.– geol. surv., 34–77. g eo lo gi a c ro at ic a geologia croatica 70/3194 ayyad, s.n., faris, m., el nahass, h.a. & saad, a.a. (2003): planktonic fo­ raminiferal and calcareous nannofossil biostratigraphy of the upper cretaceous­ lower eocene successions in the northeast sinai, egypt.– the 3th international conference, assiut, egypt, 1, 649–683. backman, j. & shackleton, n.j. (1983): quantitative biochronology of pliocene and early pleistocene calcareous nannofossils from the atlantic, indian and pa­ cific oceans.– marine micropaleontology, 8, 141–170. doi: 10.1016/0377­ 8398(83)90009­9 baumann, k.­h., young, j.r., cachao, m. & ziveri, p. (2000): biometric study of coccolithus pelagicus and its palaeoenvironmental utility, bremen: 8. ina conf. j. nannoplankton res., 22, p. 82. beadnell, h.j.l. (1905): the topography and geology of the fayum province of egypt.– survey dept., cairo, 101 p. bolle, m­p., tantawy, a., pardo, a., adatte, t., burns, s. & kassab, a. (2000): climatic and environmental changes documented in the upper palaeocene to lower eocene of egypt.– ecol. geol. helv., 93, 33–51. bralower, t.j. (2002): evidence of surface water oligotrophy during the palaeocene eocene thermal maximum: nannofossil assemblage data from ocean drilling program site 690 maud rise, weddell sea.– paleoceanograph., 7, 1–13. bramlette, m.n. & sullivan, f.r. (1961): coccolithophorids and related nan­ noplankton of the early tertiary in california.– micropaleontol., 7, 129–188. doi: 10.2307/1484276 bukry, d. (1973): low­latitude coccolith biostratigraphic zonation.– proc. deep sea drill. proj., initial rep., 15, 685–703. doi: 10.2973/dsdp.proc.15.116.1973 dickens, g.r., o’neil, j.r., rea, d.k. & owen, r.m. (1995): dissociation of oceanic methane hydrate as a cause of the carbon isotope excursion at the end of the palaeocene.– paleoceanogr., 10, 965–971. dupuis, c., aubry, m­p., steurbart, e., breggren, w.a., ouda, k., ma­ gioncalda, r., cramer, b.s., kent, d.v., speijer, r.p. & heilmann­ clausen, c. (2003): the dababiya quarry section: lithostratigraphy, geochemistry and paleontology.– micropaleontol., 49/1, 41–59. edwards, a.r. (1968): the calcareous nannoplankton for tertiary new zealand cli­ mates, tuatara, 16, 26–31. el­dawy, h.m., obaidalla, a.n., mahfouz, h.k. & abdel wahed, s.a. (2016): palaeocene­eocene transition at naqb assiut, kharga oasis, western desert, egypt: stratigraphical and paleoenvironmental inferences.– jour. of afr. earth sci., 117, 207–222. faris, m. (1988a): late cretaceous­early tertiary calcareous nannofossils from el­ qusaima area, ne sinai, egypt.– bull. fac. science qena (egypt), 2/1, 263–275. faris, m. (1988b): remarks on late palaeocene­early eocene calcareous nannofossils from gebel um huetat, safaga area, egypt.– bull. fac. science qena (egypt), 2/1, 277–297. faris, m., allam, a. & marzouk, a.m. (1989): biostratigraphy of the late cre­ taceous – early tertiary rocks in the nile valley (qena region), egypt.– geol. surv. egypt, 15, 287–300. faris, m. & strougo, a. (1998): the lower libyan in farafra (western desert) and luxor (nile valley): correlation by calcareous nannofossils.– m.e.r.c., ain shams university earth science series, 12, 137–156. faris, m., abd el­hameed, a.t., marzouk, a.m. & ghandour, i.m. (1999): early palaeogene calcareous nannofossil and planktonic foraminiferal biostratig­ raphy in central egypt.– neues jahrbuch für geology und palaöntology, 213/2, 261–288. faris, m., el­deeb, w. & mandour, m. (2000): biostratigraphy of some upper cretaceous/lower eocene successions in north and southwest sinai, egypt.– ann. geol. surv. egypt, 23, 135–161. faris, m. & zahran, e. (2002): calcareous nannofossil biostratigraphy of the late palaeocene/early eocene of el­bruk area, north central sinai, egypt.– egyptian journal of paleontology, 2, 359–369. faris, m., ayyad, s.n., el nahass, h.a. & al wosabi, kh.a.a. (2005): inte­ grated planktonic and calcareous nannofossil biostratigraphy of the upper cre­ taceous­lower eocene formations, west central sinai, egypt.– the 5th interna­ tional conference on the geology of africa, 2, 769–791. faris, m. & abu shama, a.m. (2007): nannofossil biostratigraphy of the palae­ ocene–eocene succession in the thamad area, east central sinai, egypt.– micro­ paleontogy, 53 /1–2,127–144. faris, m. & salem, r.f. (2007): palaeocene­early eocene calcareous nannofossil biostratigraphy in west central sinai, egypt.– proceeding of the 8th conference geology of sinai for development, ismailia, 1–14. faris, m. & farouk, s. (2015): calcareous nannofossils of the palaeocene–eocene transition in four sections from egypt.– turk. j. earth sci., 24, 585–606. faris, m., ghandour, i.m., zahran, e. & mosa, g. (2015): calcareous nan­ noplankton changes during the palaeocene­eocene thermal maximum in west central sinai, egypt.– turk. jour. of earth sci., 24, 475–493. gibbs, s., bralower, t.j., bown, p.r., zachos, j.c. & bybell, l.m. (2006a): shelf and openocean calcareous phytoplankton assemblages across the palaeocene­ eocene thermal maximum: implications for global productivity gradients.– ge­ ology, 34, 233–236. gibbs, s.j., bown, p.r., sessa, j.a., bralower, t.j. & wilson, p.a. (2006b): nannoplankton extinction and origination across the palaeocene­eocene thermal maximum.– science, 314, 1770–1773. ghandour, i.m., abd el­hameed, a.t., faris m., marzouk, a & maeji­ ma, w. (2004): textural, mineralogical and microfacies characteristics of the lower palaeogene succession at the nile valley and kharga oasis regions, cen­ tral egypt.– jour. geosci., osaka univ., 47/4, 39–53. haq, b.u. (1980): biogeographic history of miocene calcareous nannoplankton and paleoceanography of the atlantic ocean.– micropaleontology, 26/4, 414–43. doi: 10.2307/1485353 haq, b.u. & lohmann, g.p. (1976): early cenozoic calcareous nannoplankton bio­ geography of the atlantic ocean. marine micropaleontology, 1, 119–194. doi: 10.1016/0377­8398(76)90008­6 hay, w.w. (1964): the use of the electron microscope in the study of fossils. smithso­ nian institution. hay, w.w., mohler, h.p., roth, p.h., schmidt, r.r. & bordeauz, j.e. (1967): calcareous nannoplankton zonation of the cenozoic of the gulf coast and caribbean­antillean area, transoceanic correlation.– transactions of the gulf coast association of geological societies, 17, 428–480. hermina, m. (1990): the surroundings of kharga, dakhla and farafra oases.– in: said, r. (ed.): the geology of egypt, rotterdam, balkema, 734 p. hewaidy, a.a. & faris, m. (1989): biostratigraphy and palaeoecology of the late cretaceous­early tertiary sequence in wasif area, safaga district, eastern desert, egypt.– delta jour. of sci., 13/4,1953–1975. jiang, wise, s.w. (2006):surface­water chemistry and fertility variations in the trop­ ical atlantic across the palaeocene/eocene thermal maximum as evidenced by calcareous nannoplankton from odp leg 207, hole 1259b.– revesta micropa­ leontology, 49/4, 227–244. kahn, a. & aubry, m.­p. (2004): provincialism associated with the palaeocene/ eocene thermal maximum: temporal constraint.– marine micropaleontology, 52, 117–131. katz, m.e., pak, d.k., dickens, g.r. & miller, k.g. (1999): the source and fate of massive carbon input during the latest palaeocene thermal maximum.– sci­ ence, 286/5444, 1531–1533. kelly, d.c., bralower, t.j., zachos, j.c., premoli silva, i. & thomas, e. (1996): rapid diversification of planktonic foraminifera in the tropical pacific (odp site 865) during the late palaeocene thermal maximum.– geology, 24, 423–426. kennett, j.p. & stott, l.d. (1991): abrupt deep­sea warming, palaeoceanograph­ ic changes and benthic extinctions at the end of the palaeocene.– nature, 353, 225–229. doi: 10.1038/353225a0 khalifa, h. (1970): geology of gabal e1 shaghab area, near esna.– msc. memoir, department of geology, university of assiut, u.a.r., 85 p., 29 figs, 1 map. khalil, h. & al sawy, s. (2014): integrated biostratigraphy, stage boundaries and paleoclimatology of the upper cretaceous–lower eocene successions in kharga and dakhala oases, western desert, egypt.– jour. of afr. earth sci., 96, 220–242. khozyem, h., adatte, t., spangenberg, j.e., tantawy, a.a. & keller, g. (2013): palaeoenvironmental and climatic changes during the palaeocene– eocene thermal maximum (petm) at the wadi nukhul section, sinai, egypt.– journal of the geological society, london, 170, 341–352. khozyem, h., adatte, t., keller, g., tantawy, a.a. & spangenberg, j.e. (2014): the palaeocene­eocene gssp at dababiya, egypt–revisited.– epi­ sodes, 37/2,78–85. luning, s., marzouk, a. & kuss, j. (1998): the palaeocene of central east sinai, egypt: ‘sequence stratigraphy’ in monotonous hemipelagites.– journal of foram. res, 28, 19–39. martini, e. (1971): standard tertiary and quaternary calcareous nannoplankton zona­ tion.– in: farinacci, a. (ed.): proceedings of the 2nd planktonic conference, roma.– tecnoscienza, rome, 739–785. mcintyre, a. & be, a.w.h., (1967): modern coccolithophoridae of the atlantic ocean­i.placoliths and cyrtoliths.– deep­sea res. part a 14, 561–597. mutterlose, j., linnert, c. & norris, r. (2007): calcareous nannofossils from the palaeocene­eocene thermal maximum of the equatorial atlantic (odp site 1260b): evidence for tropical warming.– mar. micropaleontol., 65,13–31. okada, k.h. & bukry, d. (1980): supplementary modifications and introduction of code numbers to the low latitude coccolith biostratigraphic zonation.– mar. mi­ cropaleontol., 5, 321–325. ouda, k.h., berggren, w.a. & abdel sabour, a. (2016a): biostratigraphy of the upper palaeocene­lower eocene succession of gebel el aguz, northeastern kharga oasis, western desert, egypt.– revue de paléobiologie, genève, 3/1, 341–371. ouda, k.h., berggren, w.a. & abdel sabour, a. (2016b): upper palaeocene­ lower eocene biostratigraphy of darb gaga, southeastern kharga oasis western desert, egypt.– journal of afr. earth sci., 118, 12–23. g eologia c roatica faris et al.: calcareous nannofossil bioevents at the palaeocene/eocene boundary in the kharga oasis, western desert of egypt 195 perch­nielsen, k. (1985): mesozoic calcareous nannofossils.– in: bolli, h.m., saunders, j.b. & perch­nielsen, k. (eds.): plankton stratigraphy. cam­ bridge univ. press, 329–426. romein, a.j.t. (1979): lineages in early palaeogene calcareous nannoplankton.– utrecht micropalaeontological bulletins, 22, 1–230. said, r. (1990): cenozoic. the geology of egypt, puplished for the egyptian general petroleum coroporation, conoco, hurghada, inc., and repsol exploracion, 1, 451–486. speijer, r.p., schmitz, b. & luger, p. (2000): stratigraphy of late palaeocene events in the middle east: implications for low to middle latitude successions and correlations.– journal of geological society, london, 157, 37–47. strougo, a. & faris, m. (1993): palaeocene/eocene stratigraphy of wadi el da­ khl, southern galala pl.au. m.e.r.c.– ain shams university earth science series, 7, 49–62. tantawy, a.a. (1998): stratigraphical and paleontological studies on some palae­ ocene­eocene succession in egypt.– ph.d. thesis, assiut university, 273 p. tantawy, a.a. (2006): calcareous nannofossils of the palaeocene­eocene transition at qena region, central nile valley, egypt.– micropaleontology, 52, 193–222. thomas, e. (1998): biogeography of the late palaeocene benthic foraminiferal extinc­ tion.– in: aubry, m.­p., lucas, s.g. & berggren, w.a. (eds.): late palae­ ocene–early eocene: climatic and biotic events in the marine and terrestrial records. columbia univ. press, new york, ny, 214–235. thomas, e. & shackleton, n.j. (1996): the latest palaeocene benthic foramini­ feral extinction and stable isotope anomalies.– in: knox, r.o., corfield, r.m. & dunay, r.e. (eds.): correlation of the early palaeogene in northwest europe.– geological society of london special publication, 101, 401–441. tremolada, f. & bralower, t.j. (2004): nannofossil assemblage fluctuations during the palaeocene–eocene thermal maximum at sites 213 (indian ocean) and 401 (north atlantic ocean): palaeoceanographic implications.– marine micropa­ leontol., 52, 107–116. von salis, k., ouda, k., saad el din, m., tantawy, a.a. & bemasconi, s. (1998): calcareous nannofossil, foraminifera and stable isotope studies from the p/e boundary section in egypt.– strata, actes du laboratoire de geologie sedi­strata, actes du laboratoire de geologie sedi­ mentaire et paleontologie de l’université paul­sabatier, 1, 113–115. youssef, m. (2009): high resolution calcareous nannofossil biostratigraphy and pa­ laeoecology across the latest danian event (lde) in central eastern desert, egypt.– marine micropaleontology, 72, 111–128. youssef, m. (2015): evaluation of foraminifera and calcareous nannofossils changes across the late palaeocene/early eocene transition at nag el-quda section, upper nile valley, egypt.– geosciences jour., 19/4, 641–654. youssef, m. (2016): calcareous nannofossils and paleoenvironments of the palae­ ocene­eocene thermal maximum (petm) interval in central egypt.– jour. of afr. earth sci., 114, 203–219. ziveri, p., baumann, k.h., böckel, b., bollmann, j. young, j.r. (2004): biogeography of selected holocene coccoliths in the atlantic ocean.– in: thierstein, h.r. & young, j.r. (eds.): coccolithophores from molecular processes to global impact. springer, berlin, 403–453.doi: 10.1007/978­3­662­ 06278­4_15 list of calcareous nannofossil taxa bomolithus megastypus (bramlette & sullivan, 1961) bown, 2005 braarudosphaera bigelowii (gran & braarud, 1935) de­ flandre, 1947 calciosolenia aperta (hay & mohler, 1967) bown, 2005 campylosphaera eodela bukry & percival, 1971 chiasmolithus bidens (bramlette & sullivan, 1961) hay & mohler, 1967 chiasmolithus californicus (sullivan, 1964) hay & moh­ ler, 1967 chiasmolithus consuetus (bramlette & sullivan, 1961) hay & mohler, 1967 chiasmolithus danicus (brotzen, 1959) hay & mohler, 1967 chiasmolithus eograndis perch­nielsen, 1971 chiasmolithus solitus (bramlette & sullivan, 1961) locker, 1968 coccolithus eopelagicus (bramlette & riedel, 1954) bramlette & sullivan 1961 coccolithus pelagicus (wallich, 1877) schiller, 1930 discoaster anartios bybell & self­trail, 1995 discoaster araneus bukry, 1971 discoaster backmanii agnini & fornaciari, 2008 discoaster barbadiensis tan, 1927 discoaster binodosus martini, 1958 discoaster diastypus bramlette & sullivan, 1961 discoaster falcatus bramlette & sullivan, 1961 discoaster lenticularis bramlette & sullivan, 1961 discoaster mahmoudii perch­nielsen, 1981 discoaster mediosus bramlette & sullivan, 1961 discoaster mohleri bramlette & percival, 1971 discoaster multiradiatus bramlette & reidel, 1954 discoaster paelikei agnini et al., 2008 ellipsolithus bollii perch­nielsen, 1977 ellipsolithus distichus (bramlette & sullivan, 1961) sullivan, 1964 ellipsolithus macellus (bramlette & sullivan, 1961) sullivan, 1964 ericsonia robusta (bramlette & sullivan, 1961) ed­ wards & perch­nielsen, 1975 ericsonia subpertusa hay & mohler, 1967 ericsonia universa (wind & wise, 1977) romein, 1979 fasciculithus alanii perch­nielsen, 1971 fasciculithus clinatus bukry, 1971 fasciculithus bobii perch­nielsen, 1971 fasciculithus involutus bramlette & sullivan, 1961 fasciculithus lillianiae perch­nielsen, 1971 fasciculithus richardii perch­nielsen, 1971 fasciculithus thomasii perch­nielsen, 1971 fasciculithus tonii perch­nielsen, 1971 fasciculithus schaubii hay & mohler, 1967 fasciculithus tympaniformis hay & mohler in hay et al., 1967 heliolithus kleinpelli sullivan, 1964 lophodolithus nascens bramlette & sullivan, 1961 micrantholithus attenuatus bramlette & sullivan, 1961 neochiastozygus chiastus (bramlette & sullivan, 1961) perch­nielsen, 1971 neochiastozygus junctus (bramlette & sullivan, 1961) perch­nielsen, 1971 neochiastozygus perfectus perch­nielsen, 1971 neococcolithes protenus (bramlette & sullivan, 1961) black, 1967 pontosphaera exilis (bramlette & sullivan, 1961) romein, 1979 pontosphaera formosa (bukry & bramlette, 1969) ro­ mein, 1979 pontosphaera multipora (kamptner, 1948 ex deflandre in deflandre & fert, 1954) roth, 1970 pontosphaera ocellata (bramlette & sullivan, 1961) perch­nielsen, 1984 pontosphaera plana (bramlette & sullivan, 1961) haq, 1971 g eo lo gi a c ro at ic a geologia croatica 70/3196 pontosphaera pulchra (deflandre in deflandre & fert, 1954) romein, 1979 pontosphaera versa (bramlette & sullivan, 1961) sherwood, 1974 rhomboaster bitrifida romein, 1979 rhomboaster cuspis bramlette & sullivan, 1961 sphenolithus moriformis (bronnimann & stradner, 1960) bramlette & wilcoxon 1967 sphenolithus primus perch­nielsen 1971 thoracosphaera operculata bramlette & martini, 1964 thoracosphaera saxea stradner, 1961 toweius eminens (bramlette & sullivan, 1961) perch­ nielsen, 1971 toweius occultatus (locker, 1967) perch­nielsen, 1971 toweius pertusus (sullivan, 1965) romein, 1979 toweius tovae perch­nielsen, 1971 tribrachiatus bramlettei (bronnimann & stradner, 1960) proto decima et al., 1975 tribrachiatus digitalis aubry, 1996 rhomboaster cuspis bramlette & sullivan, 1961 rhomboaster spineus (shank & stradner, 1971) perch­ nielsen, 1984 zygodiscus adamas bramlette & sullivan, 1961 zygodiscus sheldoniae bown, 2005 zygodiscus plectopons bronnimann & stradner, 1961 zygrhablithus bijugatus (deflandre in deflandre & fert, 1954) deflandre, 1959 plate 1 1) braarudosphaera bigelowii (gran & braarud, 1935) deflandre, 1947, sample 12, naqb assiut section. 2) chiasmolithus bidens (bramlette & sullivan, 1961) hay & mohler 1967, sample 6, um el ghanayim section. 3, 4) campylosphaera eodela bukry & percival, 1971, sample 8, um el ghanayim section 5, 6) ericsonia subpertusa hay & mohler, 1967, sample 8, naqb assiut section. 7) ellipsolithus distichus(bramlette & sullivan, 1961) sullivan, 1964, sample 20, um el ghanayim section. 8) ellipsolithus macellus (bramlette & sullivan, 1961) sullivan, 1964, sample 23, naqb assiut section. 9, 10) fasciculithus clinatus bukry 1971, sample 5, naqb assiut section. 11, 14) fasciculithus involutus bramlette & sullivan, 1961. 11, 12) sample 14, naqb assiut section. 13, 14) sample 20, naqb assiut section. 15) fasciculithus tympaniformis hay & mohler in hay et al. 1967, sample 12, um el ghanayim section. 16) heliolithus kleinpellii sullivan (1964) sample 5, um el ghanayim section. 17, 18) micrantholithus attenuatus bramlette & sullivan (1961) sample 44, um el ghanayim section. 19, 20) neochiastozygus junctus (bramlette & sullivan, 1961) sample 23, um el ghanayim section. 21–23) zygrhablithus bijugatus (deflandre in deflandre & fert, 1954) deflandre, 1959. 21, 22) sample 13 naqb assiut section. 23) sample 41, um el ghanayim section. 24, 25) calciosolenia aperta (hay & mohler, 1967), bown, 2005, sample 9, um el ghanayim section. 26, 27) zygodiscus plectopons bramlette & sullivan, 1961, sample 7, naqb assiut section. g eologia c roatica faris et al.: calcareous nannofossil bioevents at the palaeocene/eocene boundary in the kharga oasis, western desert of egypt 197 g eo lo gi a c ro at ic a geologia croatica 70/3198 plate 2 1-4) discoaster araneus bukry, 1971, 1, 2) sample 20, naqb assiut section 3, 4) sample 35, um el ghanayim section. 5) discoaster anartios bybell &self-trail 1995, sample 20, naqb assiut section. 6) discoaster barbadiensis tan 1927, sample 42, um el ghanayim section. 7) discoaster diastypus bramlette & sullivan 1961, sample 42, um el ghanayim section. 8) discoaster falcatus bramlette & sullivan 1961, sample 22, um el ghanayim section. 9) discoaster mahmoudii perch-niesen 1981, sample 27, naqb assiut section. 10) discoaster multiradiatus bramlette & reidel 1954, sample 5, naqb assiut section. 11, 12) discoaster paelikei agnini et al. 2008, sample 36, um el ghanayim section. 13, 14) pontosphaeraexilis (bramlette & sullivan, 1961) romein, 1979, sample 9, naqb assiut section. 15) pontosphaera plana (bramlette & sullivan, 1961) haq 1971, sample 17, naqbassiut section 16) coccolithus eopelagicus (wallich, 1877) schiller, 1930, sample 44, umm el ghanayim section 17) rhomboaster bitrifida romein 1979, sample 38, um el ghanayim section. 18) rhomboaster cuspis bramlette & sullivan 1961, sample 27, naqb assiut section 19) sphenolithus moriformis (bronnimann & stradner, 1960) bramlette & wilcoxon, 1967, sample 39, um el ghanayim section. 20) sphenolithus primus perch-nielsen 1971, sample 19, um el ghanayim section. 21) tribrachiatus bramlettei (bronnimann & stradner, 1960) protodecima et al., 1975, sample 39, um el ghanayim section. 22) tribrachiatus digitalis aubry 1996, sample 41, um el ghanayim section. 23) toweius eminens (bramlette & sullivan, 1961), perch nielsen, 1971, sample 16, naqb assiut section. 24) thoracosphaera operculata bramlette & martini (1964), sample 4, um el ghanayim section. g eologia c roatica faris et al.: calcareous nannofossil bioevents at the palaeocene/eocene boundary in the kharga oasis, western desert of egypt 199 g eo lo gi a c ro at ic a geologia croatica 70/3200 2021 | 74/2 | 99–120 | 18 figs. | 1 tab. | 3 pls. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction there is no generally accepted definition of the term ‘megabed’ (marjanac, 1996; fallgater et al., 2016) but they usually refer to deposits of exceptionally large-volume sediment gravity flows (megaflows) that are rheologically complex, and that produced much thicker beds than the surrounding succession (fallgater et al., 2016). exceptionally thick beds with a virtually basin wide extent are called “seismoturbidites” by mutti et al. (1984). the term “megaturbidite” is used by bouma (1987) for thick layers (compared to the host rock), that are laterally extensive, different in composition from the host rock, and lack submarine fan geometries even if they cover several depositional processes (labaume et al., 1987). the debrite components in beds, labeled as megaturbidites or seismoturbidites, are volumetrically much more important than the derivative turbidite component (payros et al., 1999) and therefore, these terms are considered to be inappropriate for these deposits (payros et al., 1999). some gravity flow deposits with couplets or triplets related to debris flows and turbidity currents are called hybrid event beds (haughton et al., 2003, 2009; talling, 2013). similar carbonate sediments, composed of breccias, conglomerates, bioclastic arenites, and marls from other regions, especially those from dinaric foreland basins, are interpreted as megabeds (tunis & venturini, 1992; marjanac, 1996; gobo et al., 2021) or mass transport deposits (ogata et al., 2014, 2019). in the central dalmatian basin, a slightly younger southeastern part of the dinaric foreland basin, marjanac (1990, 1991, 1993, 1996) described 4 types of megabeds: 1) megaturbidites, 2) “reflected” turbidites, 3) composite turbidites, and 4) complex, bipartite type beds, composed of debrite and turbidite parts. bipartite beds described by marjanac (1996) are considered equivalent to olistostromes (abbate et al., 1970). the debrite part is composed of a) extra basinal clasts – foraminiferal limestones, b) rolled and megabeds in istrian flysch as markers of synsedimentary tectonics within the dinaric foredeep (croatia) krešimir petrinjak*, marko budić, stanislav bergant and tvrtko korbar croatian geological survey, department of geology, sachsova 2, 10 000 zagreb, croatia; (*corresponding author: kpetrinjak@hgi-cgs.hr) doi: 10.4154/gc.2021.07 abstract istrian flysch was deposited during the eocene in the dinaric foredeep and is composed of hemipelagic marls and various gravity flow deposits. the latter are predominantly 5-40 cm thick turbidites, developed mostly as laminated and cross-rippled sandstone beds (tb-e, tc-e and td-e bouma sequences). in addition to the turbidites, there are deposits characterized by a significant thickness, occasionally more than 10 m, described as complex (bipartite) megabeds. the megabeds are composed of debrites in the lower part (division i), and high-density turbidites in the upper part (division ii). the distinct clast composition of each megabed indicates that the lithoclasts were derived from tectonically active slopes and fault scarps along which collapses of the different parts of the cretaceous to palaeogene neritic carbonate succession, that underlie the flysch, occurred. the division ii deposits are well cemented, normally graded calcirudite/calcarenites composed mostly of orthophragminids, nummulitids, and red algae, originating from outer ramp environments. redeposited marl, observed in the matrix of the debrites and as intraclasts in some megabeds, implies that the collapses along the synsedimentary fault scarps and steep slopes also occurred within the foredeep itself, during the rapid tectono-sedimentary evolution of the dinaric foreland basin. compressed basinal sediments composed of arenite and marl alternations and c) foraminiferal debris. the turbidite part is normally graded, composed mostly of foraminiferal debris and lacking large lithoclasts (marjanac, 1993). in the slightly older counterparts of the dinaric foreland basin north of istria, (friuli and the julian basin in italy and slovenia), the mass transport deposits (mtds) that are described in 5 subunits (u1-u5) were deposited by different depositional processes. the authors (ogata et al., 2014) indicate that the processes generating the friuli and julian mtds are composed of a) a debris-blocky flow/avalanche bearing out-sized carbonate and siliciclastic slide blocks (responsible for the deposition of subunits u1 and u2), b) a diluted debris/grain flow (deposition of subunit u3), and c) an upper high to low-density fully turbulent flow (deposition of subunits u4 and u5). mass flows can transport and incorporate both intraand extra-basinal material and their formation commonly implies processes of stratal disruption and lithological mixing and thus forming a characteristic “block-in-matrix” fabric (pini et al. 2012; ogata et al., 2020). thus, the single event beds that display bipartite organization, with each part inferred to reflect a distinct depositional process, are referred also as mtds. among other mtds, bipartite megabeds, composed of debrite and turbidite parts, are also described in the dinaric wedge-top basin in northern dalmatia (gobo et al., 2021). in this research, sedimentological and petrographic data about megabeds of the istrian flysch is used to shed some light on the environmental conditions, depositional mechanisms, and the origin of the resedimented coarse-grained carbonate material. to determine the variations and provenance of the carbonate material, qualitative and quantitative analyses of carbonate clasts were performed. furthermore, the analysis of bioclastic grains was carried out to determine the original depositional palaeoenvironments of the redeposited bioclasts. the relatively tectonically article history: manuscript received january 15, 2020 revised manuscript accepted february 18, 2021 available online may 06, 2021 keywords: adriatic microplate, dinaric foreland basin, mass transport deposits, eocene, external dinarides g eo lo gi a c ro at ic a 100 geologia croatica 74/2 undisturbed dinaric foreland deposits that were not involved in the external dinarides fold-and-thrust belt are exclusively exposed in centra istria since other equivalent parts of the foreland are covered by neogene deposits and/or by the adriatic sea (korbar, 2009). thus, istria is an excellent location for further studies of the rather complex foreland basin evolution. there are no deep seismic and exploration wells in istria needed for relevant basin modeling. however, the presented research resulted from some insight in the formation, composition and spatial distribution of some megabeds. for further correlation of the studied megabeds, more detailed geological mapping and precise biostratigraphic analyses are needed. so far, this research has provided new data about the istrian megabeds regarding the composition, and provenance of the carbonate material, facies models and triggering mechanisms. 2. geological setting the istrian peninsula is located on the northwestern part of the eastern adriatic coast and it predominantly belongs to the adriatic foreland (fig 1). the ne mountain belt of the peninsula (fig. 1) belongs to the fold-and-thrust belt of the external dinarides, formed during alpine orogenesis, caused by the collision of the adriatic microplate (adria) and the eurasian plate (schmid et al., 2008; korbar, 2009; špelić et al., 2021). the oldest rocks on the istrian peninsula are the jurassic and cretaceous limestones that were deposited on the pre-orogenic long-lasting adriatic carbonate platform (vlahović et al., 2005). a regional unconformity separates the jurassic-cretaceous shallow-marine carbonate succession from the palaeogene synorogenic carbonates deposited in the distal foreland (otoničar, 2007). this late cretaceous and early palaeogene unconformity is marked by palaeokarst that occurred during the forebulge uplift and the emersion of the adriatic carbonate platform (otoničar, 2007). also, a broad istrian anticline, striking ne-sw, was probably formed during the late cretaceous, since the deformed and palaeokarstified cretaceous carbonates are diachronously overlain by the palaeogene succession (matičec et al., 1996). the lowermost part of the palaeogene succession is characterized by localized occurrences of the freshwater or brackish kozina beds (šikić & polšak, 1973; marjanac & ćosović, 2000; ćosović et al., 2008). the kozina beds are overlain by ypresian to middle-late lutetian foraminiferal limestones (drobne, 1977; marjanac & ćosović, 2000) which were deposited on a fully marine carbonate ramp (ćosović et al., 2004) developed in the distal part of the dinaric foreland basin (otoničar, 2007). the foraminiferal limestones are often informally subdivided into four separate members: miliolid-, alveolinid-, nummulitidand discocyclina limestones (drobne 1977; šikić & pleničar, 1975; velić et al., 2003; vlahović & velić, 2009). the units are generally in superposition and indicate progressive deepening of the ramp (ćosović et al., 2004) during the migration of the foreland basin to the sw (otoničar, 2007; korbar, 2009). the foraminiferal limestones are overlain by figure 1. the geological map of the croatian part of the istrian peninsula with the studied locations indicated by black circles (croatian geological survey, 2009). globigerina marls are not separated as a lithostratigraphic unit but as a member within the foraminiferal limestones. however, according to new data and more detailed maps, globigerina marls within the investigated area, are reclassified and published as a member within the istrian flysch (bergant et al., 2020) as presented in fig. 2. g eologia c roatica 101petrinjak et al.: megabeds in istrian flysch as markers of synsedimentary tectonics within the dinaric foredeep (croatia) the so-called transitional beds composed of “marls with crabs” and “globigerina marls”. the “marls with crabs” are clayey fossiliferous wackestones and packstones (šikić & pleničar, 1975; marjanac & ćosović, 2000; tarlao et al., 2005), deposited during the gradual transition from the neritic carbonate ramp to the deeper-water distal foredeep. massive “globigerina marls” (or “subbotina marls”) are deposited in deeper environments and are considered to be hemipelagic deposits (juračić, 1980). the clastic part of the foreland succession is deposited in the foredeep and is referred to as flysch (marinčić, 1981). in the wider eastern adriatic region flysch is recognized as a major lithostratigraphic unit, which marks the beginning of the dinaric orogenic deformations in the area (aubouin et al., 1970; babić & zupanič, 1983; korbar, 2009). the whole istrian palaeogene succession (figs. 1 and 2) is probably deposited within an underfilled peripheral foreland basin as described by sinclair (1997), with flysch deposited in the foredeep in front of the once migrating dinaric wedge (otoničar, 2007; korbar, 2009). based on the plankton and benthic foraminiferal ratio, živković & babić (2003) have estimated the water depth of the foredeep to about 900-1200 m. the flysch is characterized by the alternation of hemipelagic marls and gravity-flow deposits (predominantly turbidites) composed of a) mixed carbonate-siliciclastic detritus or b) carbonate detritus (magdalenić, 1972; marinčić, 1981; babić & zupanič, 1996; marinčić et al., 1996; bergant et al., 2003). mixed carbonate-siliciclastic turbidites show longitudinal palaeotransport directions toward the ese which led to the conclusion that the material was supplied from the rising dinarides and from the alps (magdalenić, 1972; marinčić et al., 1996; babić & zupanič, 1996). these turbidites are regarded as turbidites deposited by low density turbidity currents (marinčić et al., 1996). carbonate beds are often thin turbidites but also thick, bipartite beds composed of breccias, conglomerates, bioclastic arenites/siltites, and marls (babić & zupanić, 1996; bergant et al., 2003), and show a palaeotransport direction towards the nne, generally perpendicular to the se direction of the mixed carbonate-siliciclastic turbidites (babić & zupanič, 1996). babić & zupanič (1996) conclude that the carbonate detritus was supplied from the foreland uplift (forebulge), situated to the south, characterized by carbonate shoals and subaerial exposure. the progressive evolution of the istrian foredeep fill has been documented by marinčić et al. (1996) and is described as the istrian flysch – a succession of clastic rocks characterized by a coarsening upward trend and outlined with zones of “distal” and “proximal” flysch. according to marinčić et al. (1996), the total thickness of the flysch succession is estimated to be around 300-350 m (fig. 2). although some published (mikes et al., 2008) and unpublished studies argued for a late oligocene or even miocene age of the istrian and dalmatian flysch, the majority of the researchers confirm a middle eocene age (aubouin et al., 1970; krašeninnikov et al., 1968; piccoli & proto decima, 1969; magaš, 1973; polšak & šikić, 1973; šikić & polšak, 1973; šikić & pleničar, 1975; benić, 1991; živković & babić, 2003; babić et al., 2007; živković & glumac, 2007). we accepted the middle eocene age proposed by babić et al. (2007) and ćorić et al. (2008), since their data was obtained from the investigated logged successions and by more than one biostratigraphic method. for this study, six different megabeds were investigated. the locations of the investigated beds are presented in fig 1. the relative stratigraphic position of each megabed was determined according to the data of direct observation in the field, from the published and unpublished geological maps, and the results of previous biostratigraphic research. we can conclude that the studied megabeds are present in the different stratigraphic positions within the istrian flysch succession. the kaldir, šublentica, and hum megabeds are located in the lower part, while the gračišće, koromačno, and probably the plomin megabeds are in the middle part of the istrian flysch succession (fig. 2). according to živković & babić (2003) the age of the gračišće megabed is bartonian (plankton foraminifera zone p11-p13). the kaldir megabed is considered to be of a middle eocene age based on the vicinity of the investigated sections by živković & glumac (2007). the ages of other megabeds are based on the data profigure 2. the schematic geological column of the middle eocene istrian flysch succession and the underlying cretaceous and palaeogene neritic carbonates, with the general relative stratigraphic positions of the investigated sections. intervals of the underlying cretaceous rudist limestones and palaeogene foraminiferal limestones are not in a general scale given for flysch. g eo lo gi a c ro at ic a 102 geologia croatica 74/2 fi gu re 3 . d iv is io n i c la st c om po si tio n. g eologia c roatica 103petrinjak et al.: megabeds in istrian flysch as markers of synsedimentary tectonics within the dinaric foredeep (croatia) vided on basic geological maps: the plomin megabed – middle eocene according to šikić & polšak (1973), the koromačno megabed – middle to upper eocene according to magaš (1973), the šublentica megabed – middle eocene according to polšak & šikić (1973), and the hum megabed – middle eocene according to šikić & pleničar (1975). since the information on the megabeds age is somewhat scarce, their precise correlation is not yet possible. for a better understanding of the stratigraphic relationships between the megabeds more precise dating is needed. 3. methods during the field investigation, information on boundary types, sediment composition, layer thickness, grain size, fossil content, and internal structures was collected and presented on graphic logs. because of the recognized general compositional variation within all the studied megabeds, two different methodologies were used: 1) analysis of coarse-clast composition of breccia, referred to as division i; 2) analysis of the composition of calcirudites and calcarenites, referred to as division ii. 1) to determine the clast compositions representative for division i of each megabed, the most exposed parts of the outcrops were selected. between 200 and 300 clasts within the selected areas were classified and counted. the clasts were categorized based on their fossil content and lithological characteristics. the fossil content was determined by hand lens examination in-situ where possible. in addition, some samples were analyzed microscopically. the categories are based on the lithostratigraphic units presented on the geological map (fig. 1). the categories are: lower-, upper-, or undifferentiated cretaceous limestones, foraminiferal limestones, flysch (marls), rhodoliths, and undetermined clasts. the large rhodoliths (>5 cm in diameter), observed in two megabeds are added to separate categories although they are not attributed to any lithostratigraphic unit presented in fig 1. the cretaceous clasts were classified on the basis of their foraminiferal content according to velić (2007). foraminiferal limestones were additionally separated according to their predominant large benthic foraminifera content of the miliolid-, alveolinid-, nummulitidor discocyclina limestones as described by polšak & šikić, (1973); šikić & polšak, (1973); šikić & pleničar, (1975); vlahović & velić, (2009), and an additional algal foraminiferal limestones category. clasts of foraminiferal limestones abundant in red algae (rhodoliths and coralline debris) were separated out as algal foraminiferal limestones. the foraminiferal limestones with abundant glauconite grains were categorized as transitional beds. clasts that had no distinguishable features were labeled as “not determined”. photomicrographs of the most characteristic clasts for each bed are presented as a supplement (plates 1, 2, and 3). limestone clasts were distinguished according to dunham’s (1962) classification modified by embry & klovan (1971). table 1. results of division ii bioclastic material analysis. log group/ sample 1 2 3 4 5 6 7 8 9 10 11 12 lithoclasts (%) matrix (%) cement (%) ortophragminids (%) nummulitids (%) encrusting foraminifera (%) red algae (%) bryozoans (%) encinoderms (%) mollusks (%) rotallid foraminifera and hyaline fragments (%) not determined (%) h um hum 2 13 0 0 54 9 0 9 0 2 0 11 1 hum 3a 1 17 0 0 32 26 0 12 2 5 0 4 1 hum 3a 2 21 0 0 36 15 2 9 1 2 3 8 3 hum 3b 10 2 0 54 6 0 13 2 2 0 10 2 hum 5a 6 5 1 52 14 0 7 0 1 0 8 6 hum 5b 3 4 1 37 3 0 18 4 2 0 19 9 pl om in pl-4 12 4 0 35 33 1 9 1 2 0 3 2 pl-3 11 8 0 35 27 2 9 1 4 0 2 3 ka ld ir kaldir 1a 1 5 0 41 5 0 23 3 0 0 14 7 kaldir 1b 5 6 1 35 7 0 24 1 2 0 14 4 šu bl en tic a šub-ii 1 6 9 0 29 11 0 24 0 5 2 10 4 šub-ii 3 13 11 0 27 18 0 11 1 3 3 10 1 šub-8 16 4 0 26 28 0 17 0 2 0 5 1 g ra či šć e gračišće 1 8 7 0 33 11 0 20 6 4 0 9 2 gračišće 2 16 6 0 31 25 0 17 1 1 0 4 0 ko ro m ač no kor-ii i 27 5 0 16 13 0 28 0 3 0 5 3 kor-ii 2 22 4 0 21 13 0 31 1 1 0 4 3 g eo lo gi a c ro at ic a 104 geologia croatica 74/2 2) to determine the composition of calcirudites and calcarenites, thin sections of 17 selected samples were prepared and analyzed by standard petrological microscope. the sampling locations are marked on each log. the division ii samples were determined as bioclastic calcarenites to calcirudites composed predominantly of skeletal debris. the modal distribution of the components in thin section was estimated using a point-counting method described in flügel (2004). during point-counting, the constituents were classified into 12 groups: 1) lithoclasts, 2) matrix – micrite, 3) cement – sparite, 4) orthophragminid, 5) nummulitid, 6) encrusting foraminifera, 7) red algae, 8) bryozoans, 9) echinoderms, 10) molluscs, 11) hyaline fragments and 12) non-determinable grains. the modal distribution of the main constituents was estimated by point-counting 200-300 grains. due to sparse directional structures in the istrian megabeds, the palaeotransport directions have been measured only in one location (hum). the structures used to measure palaeotransport directions are ripple marks and a flute cast. 4. results all the six studied megabeds are distinguished from other gravi ty flow deposits of flysch succession by their thickness, composition, and internal bipartite structure. clast composition for all division i breccia is given in fig 3., while the composition of the analyzed division 2 calcirudite and calcarenite is given for each studied megabed in table 1. within division 1, two facies types are distinguished, as facies a and facies b. facies a is a clast supported breccia with sparse marl matrix. facies b is a chaotic, marl dominated, matrixrich breccia with rip-up clasts, and a greater total thickness than facies a. 4.1. the šublentica section the unconformable contact of the istrian flysch and the cretaceous limestones is described at the šublentica section (wgs84 coordinates: lat 45° 19’ 2.3808”, long 13° 48’ 29.8404”). a hiatus was recognized in this section and the megabed directly overlies the upper cretaceous rudist limestones (fig. 4). the boundary is discordant and erosional (fig. 5) suggesting tectonic tilting and the partial collapse of the underlying neritic carbonates prior to or synchronously with the deposition of the megabed. the division i breccia interval is 1.5 m thick, poorly sorted and clast supported. carbonate clasts are from 0.1 to 1 m in size. upper cretaceous limestones (40%) and foraminiferal limestones clasts (40%) predominate, while undifferentiated cretaceous limestone clasts (18%) and transitional beds (limestones with glauconite; 2%) are less abundant. the matrix is composed of marl and large benthic foraminifera (nummulites and orthophragminids). fig. 3a shows the composition of the division i breccia, with selected clast microfacies photomicrographs of foraminiferal and cretaceous limestones presented in plate 1 a, b, and c. the breccia gradually transitions to the division ii interval which consists of normally graded calcirudite and up-section to normally graded calcarenites. the most common constituents of division ii material are orthophragminids (26-29%), nummulitids (11-28%), red algae (11-24%), and lithoclasts (6-16%). the proportions of all constituents in the investigated samples are shown in table 1 and illustrated in plate 1d. the section ends with the alternation of marl and amalgamated normally graded calcirudite beds (fig. 4). 4.2. the hum section a 40 m thick interval of the palaeogene foredeep basin fill was logged near the town of hum (wgs84 coordinates: lat 45° 21’ figure 4. the šublentica column shows an unconformable (erosional) contact of the cretaceous limestones and the overlying šublentica megabed (istrian flysch). g eologia c roatica 105petrinjak et al.: megabeds in istrian flysch as markers of synsedimentary tectonics within the dinaric foredeep (croatia) 3.5706”, long 14° 2’ 42.5466”, fig. 6). the interval is composed of an alternation of marl and five carbonate beds. the most prominent bed is the 9 m thick megabed hum 3 (fig. 7a) which shows the characteristic bipartite structure with visible division i and division ii components. the other carbonate turbidite beds (labeled hum 1, 2, 4, 5 on fig.6) are composed of normally graded bioclastic calcirudite/calcarenite of various thicknesses (0.6 – 3 m). the lower bedding surface of each bed is sharp and erosional, implying that the gravity flow eroded previously deposited basinal sediments. the hum 3 megabed is composed of division i breccia/conglomerate in the lower/bottom part, and the division ii – normally graded calcirudite/calcarenite in the upper part. the maximum thickness of the laterally thinning breccia/conglomerate interval is 5 m, and the lower bedding surface is erosional. the majority of visible clasts vary in size from a few cm to 0.75 m in diameter. boulders/clasts are mostly (sub)rounded although rarely some angular clasts occur. the division i conglomerate/breccia is clast supported with a sparse matrix (referred to as facies a, fig 7a). matrix is composed of marl, small lithoclast fragments and foraminiferal debris (nummulitid and orthophragminid tests). the major lithological components are cretaceous limestones (88%) while foraminiferal limestones (9%) and other constituents (3%) are less abundant. interestingly, the lower cretaceous limestone clasts were only observed in this megabed. the clast composition is presented in fig. 3b and selected photomicrographs of lower-, upper cretaceous and foraminiferal limestone clast microfacies are presented in plate 1e, f, and g. division ii is composed of normally graded calcirudite and calcarenite with the following composition: orthophragminids (32-54%), nummulitids (6-26%), and red algae (9-13%), as prefigure 5. photograph of the šublentica outcrop showing a discordant and erosional boundary between the cretaceous limestones and overlaying megabed. figure 6. geological column showing the 10 m thick hum megabed (3) and carbonate turbidites (1, 2, 4 & 5). g eo lo gi a c ro at ic a 106 geologia croatica 74/2 sented in table 1. the hum 2 and 5 beds are also composed of normally graded calcirudite and calcarenite with the same main constituents, but in different proportions (table 1). based on the uniform composition, it is assumed that the carbonate detritus source for the turbidites (hum 2 and 5), and megabed (hum 3) was the same. a palaeotransport direction of 165° was measured from flute casts observed on the lower bedding plane of the hum 2 turbidite (fig. 6), and 195° on ripple marks observed on the upper bedding plane on the hum 3 megabed, and 230° on turbidite hum 5 (fig. 6). these data, though insufficient for statistical assessment, indicate that palaeotransport of the more proximal megabeds was locally generally towards the s, as measured in the hum section (fig. 6). 4.3. the kaldir section the studied outcrop of the kaldir megabed is located near kaldir village (fig. 1, wgs84 coordinates: lat 45° 18’ 43.1598”, long 13° 51’ 16.9056”). this megabed (fig. 8) is approximately 25 m thick, composed of limestone breccia (divison i) in the lower part and the normally graded calcirudite/calcarenite in the upper part (division ii). the geographic distribution of the kaldir megabed is shown on fig. 9. when compared to the other megabeds, the kaldir division i displays a significant difference in clast size and shape and very low marl content. the contact between the kaldir megabed and the underlying marl is sharp and erosional. the largest clast lies directly on the underlying marl at the bottom of the sequence and has a visible dimension of 5 x 10 m (fig. 10a). the breccia is clast supported, unsorted with a sparse matrix composed of fine-grained rock debris. clasts are angular, indicating short transport distances. a normal gradation is visible towards the upper part of division i. the clast composition is as follows: upper cretaceous limestones 90%, foraminiferal limestones 9%, and undetermined clasts 1%. also, a bauxite clast was observed. the composition is presented in fig. 3c, while clast microfacies of upper cretaceous and foraminiferal limestones are presented in plate 2 a, b, c. the majority of the foraminiferal limestone clasts are classified as discocyclina limestones. some of the discocyclina limestone intraclasts (plasticlasts) are plastically deformed between the larger cretaceous boulders and are tightly packed (fig. 10b). this phenomenon indicates that some of the discocyclina limestones were not fully consolidated during their resedimentation and deposition in the breccia. the transition to a normally graded 3 m thick calcirudite/calcarenite (division ii) unit is gradual. the most common constituents of bioclastic material are: orthophragminids (35–41%), red algae (23–24%), and rotaliid foraminifera including hyaline fragments (14%). the proportions of all constituents in the investigated samples are shown in table 1 and illustrated in plate 2d. figure 7. the outcrop photographs of the division i deposits, showing clast supported breccia with sparse marl matrix (facies a). (a) hum megabed division i clast supported breccia/conglomerate with sparse matrix; (b) plomin megabed division i clast supported breccia with sparse marl matrix. the geological hammer is 32 cm long. figure 8. the kaldir megabed column. g eologia c roatica 107petrinjak et al.: megabeds in istrian flysch as markers of synsedimentary tectonics within the dinaric foredeep (croatia) 4.4. the gračišće section the gračišće megabed is located south-east of the town of gračišće (wgs84 coordinates: lat 45° 12’ 59.6844”, long 14° 0’ 29.7”, fig. 1). the contact with the underlying marls is covered by vegetation and the lower bedding surface of the gračišće megbed is therefore not visible. the megabed is a bipartite bed with chaotic breccia (division i) that is matrix supported (referred to as facies b) in the lower part and a well cemented, normally graded calcirudite/calcarenite in the upper part, with a total thickness of 40 m (fig. 11). the lower breccia interval is 25 m thick, lenticular in shape, and pinches out laterally. this breccia is matrix supported with predominantly sub-angular clasts (fig. 12a). the most abundant clasts are foraminiferal limestones (75%) and marl clasts (17%), while rhodolith fragments (3%), upper cretaceous limestones (2%), undifferentiated cretaceous limestones (1%), transitional beds (1%) and undifferentiated clasts (1%) are less represented. the composition is presented in fig. 3d and the selected algal foraminiferal limestone clast microfacies photomicrograph is presented in plate 2e. the matrix is a mix of marl, fragmented bioclasts and smaller lithoclasts. bioclasts are mostly foraminiferal debris (nummulitids and orthophragminids) and rhodoliths. most clasts are < 10 cm diameter, while marl clasts are significantly larger and can be up to 50 cm across (fig. 12b). the division i breccia gradually transitions into a well cemented, normally graded calcirudite/calcarenite in the upper part of the section. the most common constituents of division ii material are: orthophragminids (31-35%), nummulitids (11-25%), red algae (17-20%), and lithoclasts (8-16%). the ratios of all constituents in the investigated samples are shown in table 1 and illustrated in plate 2f. figure 9. geological map showing the kaldir megabed spatial distribution, modified after bergant et al. (2020). figure 10. the kaldir division i breccia. (a) the 10x5 m boulder of the upper cretaceous limestone in the base of the kaldir megabed. the contact between the kaldir megabed and the underlying marls is sharp and erosional. (b) the discocyclina limestones occur as plastically deformed clasts compressed between the larger cretaceous clasts. the geological hammer head is 19 cm long. g eo lo gi a c ro at ic a 108 geologia croatica 74/2 4.5. the plomin section the plomin megabed crops out on the road cut nw of plomin village (wgs84 coordinates: lat 45° 8’ 45.6612”, long 14° 10’ 19.5198”). as a consequence of tectonic deformation along the nearby n-s striking fault (fig. 1) the beds are relatively inclined with average bed dip azimuth and dip angle of 150/40. the lower part of the plomin megabed and the contact with the underlying marls is covered by vegetation and colluvium. the studied bed is composed of a 3 m thick division i breccia in the lower part (fig. 7b) and 17 m of normally graded bioclastic calcirudite/calcarenite in the upper division ii (fig. 13). the breccia is composed of boulder-sized clasts with an average longer axis of 20–30 cm. the largest measured clast is 50 cm in diameter. the lithological composition of the breccia is foraminiferal limestones 93%, transitional beds 2%, marl 2%, and undetermined clasts 3%. the figure 11. the gračišće megabed column. figure 12. photographs of the gračišće megabed (a) the outcrop of the gračišće megabed with marked divisions. the holes (casts) within division i are formed because of the selective erosion of marl clasts. (b) photographs of marl clasts within division i, facies b of the gračišće megabeds. the marl clasts are significantly larger than the limestone clasts. the geological hammer is 32 cm long. g eologia c roatica 109petrinjak et al.: megabeds in istrian flysch as markers of synsedimentary tectonics within the dinaric foredeep (croatia) clast composition is presented in fig. 3e and selected photomicrographs of foraminiferal limestone clast microfacies are presented in plate 3a, b, and c. the breccia is mostly clast supported, with a sparse matrix. the matrix is a mix of marl, fragmented bioclasts and smaller lithoclasts. bioclasts are mostly foraminiferal debris (nummulitids and orthophragminids) and rhodoliths. the carbonate breccia (division i, facies a) gradually transitions to a 17 m thick normally graded calcirudite/calcarenite (divison ii) and the matrix content decreases. calcirudite is a well cemented, normally graded bed without a marl matrix, with a maximum clast size of 10 cm in diameter. the most common constituents of bioclastic material are ortophragminids (35%), nummulitids (27–33%), lithoclasts (11–12%), and red algae (7–18%). the proportions of all constituents in the investigated samples are shown in table 1 and illustrated in plate 3d. marl clasts occur in the middle part of the calcirudite zone, have an elongated shape, parallel orientation, and are 30-40 cm long and up to 6 – 10 cm thick. the size of the marl clasts gradually decreases towards the upper part of the calcirudite zone. calcirudite gradually transitions to calcarenite (normal gradation) with visible parallel lamination and indistinct cross lamination unsuitable for palaeotransport measurements. the upper part of this megabed ends with a massive marl interval. the plomin megabed is overlain by an interval of about 20 m of continuous flysch, composed of marl and thin carbonate and mixed carbonate and siliciclastic turbidites. 4.6. the koromačno section the koromačno section of the istrian flysch is located in koromačno quarry (wgs84 coordinates: lat 44° 58’ 10.8366”, long 14° 7’ 53.94”). besides division i and division ii, a transitional zone is outlined in the koromačno megabed (figs. 14 and 15a). the transitional zone has characteristics of both the lower division i and upper division ii. the characteristics of division i are large marl clasts (largest measured clast with long axis of 1 metre). the similarity with the upper division ii is the composition of a distinctly graded calcirudite fabric. the lower bedding surface of the koromačno megabed is not exposed at this location, but underlying calcarenite and marl beds are recognized in the vicinity. the lower division i (facies b, fig 15b) interval is composed of a matrix supported breccia with large clasts of marl and limestone lithoclasts. the clast composition is: foraminiferal limestones 80%, transitional beds 3%, marl clasts 16%, and undetermined clasts 1%. the clast composition is presented in fig. 3f and selected foraminiferal limestone clasts microfacies photomicrographs are presented in plate 3 e, f, and g. as in the gračišće megabed, the matrix is a mix of marl and fragmented bioclasts (nummulitids and orthophragminids and rhodoliths). in the middle part, labeled as the transitional zone, the content of the marl matrix rapidly decreases and well cemented calfigure 13. the plomin megabed column. g eo lo gi a c ro at ic a 110 geologia croatica 74/2 cirudite becomes dominant. the largest clasts are outsize marl clasts with long axis dimensions of 1 cm to 1 m. marl clast size decreases up-section. transitions between these parts are gradual. the division ii interval follows the transitional zone and is marked by the absence of marl clasts. it is composed of normally graded calcirudite and calcarenite. the most common constituents of division ii material are: red algae (28-31%), lithoclasts (22-27%), orthophragminids (16-21%), and nummulitids (13%). the ratios of all the constituents in the investigated samples are shown in table 1 and illustrated in plate 3h. 5. interpretations the studied beds are bipartite, composed of debris flow deposits in the lower part (division i) with a gradual transition to a highdensity turbidity current deposit in the upper part (division ii). 5.1. division i within division i two facies types are recognized and both are interpreted as debris-flow deposits that suggest “en masse” deposition after cohesive freezing. facies a is a clast supported conglomerate/breccia, normally graded, with sparse matrix. this facies is observed at the hum, plomin, and šublentica sections. the lithological composition of the clasts is different in each of the investigated beds (fig. 3). the marl (rip-up) clasts in facies a are found only in the plomin section. weak normal grading is recognized in the upper part of the division at the hum and šublentica sections. the matrix is composed of marl and bioclasts, mostly nummulitids and orthophragminids. facies b of division i is a chaotic, matrix-supported breccia with outsized rip-up clasts, and a greater total thickness than facies a. the characteristic by which the described facies are distinguished is the amount of matrix and the marl content. facies b is observed at koromačno and gračišće. the matrix is a mix of marl, fragmented bioclasts and smaller lithoclasts. bioclasts are mostly foraminiferal debris (nummulitids and orthophragminids) and rhodoliths. the bipartite organization is a consequence of the transformations from debrite flow to turbidity current, as the debris flows are considered to be one of the mechanisms for generating turbidity currents (hampton, 1972; lowe, 1982; mulder & alexander, 2001; shanmugam, 2006; felix et al., 2009). facies a deposits are related to clast-dominating debris flows, while facies b deposits are related to more marl (mud) rich debris flows. observed differences in the matrix and the marl content might be related to differences in the initial composition of the mass flow and the evolution of the flow. the division i at kaldir megabed is singled out for its unique properties: total thickness, clast size and angular shape, and total lack of matrix. the clast size (largest measured clast is 5x10 m) and angular clast shapes suggest a very short transport distance. the lack of matrix indicates a transport mechanism different to a cohesive debris flow, probably a large-scale submarine rockavalanche. figure 14. the koromačno megabed column. g eologia c roatica 111petrinjak et al.: megabeds in istrian flysch as markers of synsedimentary tectonics within the dinaric foredeep (croatia) 5.1.1. the composition of division i clasts the studied clast composition indicates that division i material (clasts) was derived from different parts of the cretaceous to pala eo gene neritic carbonate succession that underlies the eocene flysch. the most common clasts determined in each megabed, categorized according to the previously defined major lithostratigraphic units, are foraminiferal limestones and upper cretaceous rudist limestones, as shown in fig. 1. the lower cretaceous clasts are only observed in the hum megabed. rare bauxite and karstified cretaceous limestone clasts were only recognised in the kaldir megabed. the karstified upper cretaceous limestone boulder with bauxite karst infills has been described by tarlao et al., (1995) in a debrite within the istrian flysch southwest of pazin (fig. 1). the palaeo-karstified cretaceous limestones and bauxite clasts are related to the regional unconformity within the adriatic carbonate platform succession that was formed during the late cretaceous and early palaeogene emersion of the forebulge (otoničar, 2007). 5.2. division ii division ii intervals are up to 10 m thick, clast supported, and normally graded, calcirudite/calcarenites and are seen in all the studied megabeds. towards the top of the interval there is a gradual transition, first from calcirudite to calcarenite, and eventually to calcisiltite grain size. in the uppermost part of division ii, horizontal and cross lamination are observed in calcarenites or calcisiltites in the hum and plomin megabeds. division ii is overlain by a massive marl deposited from the turbidity current tail. division 2 of the megabeds is interpreted as a co-genetic turbidite deposited by a highto low-density current (lowe, 1982). 5.2.1. the composition of division ii as result of point-counting calcirudite/calcarenite samples of the division ii interval, 12 different constituents are distinguished and grouped. the results of division ii composition analysis (table 1) shows that the most abundant grains in division ii are orthophragminids, nummulitids, red algae, and lithoclasts. this specific composition shows a clear predominance of bioclastic material derived from the outer carbonate ramp environments as described in eocene carbonate ramp models in hallock & glenn (1986), ćosović et al. (2004), and bassi (2005). the coralline rhodolites were probably formed along intrabasinal, isolated banks, characterized by strong water currents and reduced sediment input (rasser & piller, 2004; barattolo et al., 2007). the lithoclasts observed are grains of older limestone rocks from the cretaceous-palaeogene limestone succession (extraclasts). the most abundant extraclasts are mudstones or wackestones containing sparse unidentifiable bioclasts. the matrix is micrite (group 2), while sparite cement is scarce (group 3). the large benthic foramniferal taxa are assigned to groups 4, 5 and 11. the other skeletal grains are grouped according to their taxa. the calcirudite and calcarenite microfacies of division ii with some of the most abundant constituents is presented in plate i d, h, plate ii d, f and plate iii d, h. 6. discussion 6.1. palaeotransport directions in the palaeotransport model for the pazin (istrian) basin provided by babić & zupanič (1996), the palaeotransport direction of carbonate beds composed of debrite and turbidite unit is towards the nne. also, babić & zupanič (1996) suggest the existence of land and shelf environments to the ssw of the former pazin basin from where the carbonate material was derived. since the data about the palaeotransport directions found in the studied megabeds is scarce, we can assume that the major source of carbonate material were fault dissected or a locally over steepened distal foredeep slopes (cf. sinclair, 1997; barnolas & teixell, 1994), that were located along the southern margin of the istrian flysch basin, as proposed by babić & zupanič (1996). according to that model, all the studied megebeds were deposited by gravitational flows on the distal slopes of the foredeep, along the figure 15. (a) outcrop of the koromačno megabed showing two divisions and a transitional zone in the middle. the chaotic, matrix supported breccia in the lower part (division i) gradually transitions into the transitional zone, composed of cemented calcirudite breccia with large marl clasts (transitional zone). the normally graded calcirudite lacking outsized marl clasts is located at the top (division ii). (b) marl clast within division i breccia, facies b part of koromačno megabed. the clast dimension is 2 x 1 m at outcrop. g eo lo gi a c ro at ic a 112 geologia croatica 74/2geologia croatica 74/2 transitional zone between the basin and the distal carbonate ramps to the s, indicating the transport was towards the n. however, palaeotransport measurements within this study were derived from only one megabed on the hum section and two from the thick carbonate turbidites in the succession (fig. 6). according to this data the paleaotransport of more proximal megabeds was locally towards the s. combining the observed data within this study (palaeotransport direction on hum section) and older research (babić & zupanič, 1996), we can assume that the carbonate detritus had multiple sources and transport directions, with the major transport direction towards the n and minor transport towards the s (figs 16 and 17). 6.2. the source of shallow-water bioclastic detritus shallow-water bioclastic detritus is a constituent of the studied megabeds and is observed in division i mixed with marl in the matrix, and as grains of bioclastic calcirudite/calcarenites of division ii. the source area of the bioclastic detritus was a synchronous shallow water carbonate ramp attached to flysch basin from the south (fig. 16). carbonate ramps in a foreland basin setting could be formed on an underfilled foreland basin margin (sinclair, 1997; bosence 2005) or developed on overthrusts and thrust folds, as described in northern dalmatia (ćosović et al., 2018). since thrusts and thrust-top deposits are not recognized in the northern part of the istrian flysch basin, a more probable location for the ramp is in the south, as a distal, marginal (forebulge) part of the dinaric foreland basin (otoničar, 2007). the distal margin of low-latitude, underfilled foreland basins is a favoured site for the accumulation of large carbonate platforms and ramps (sinclair, 1997; bosence 2005). alternatively, it can be argued that the bioclastic detritus originated from stratigraphically older, weathered foraminiferal limestones. if that were the case, its composition would include fossils from other foraminiferal limestone strata, e.g. alveolinid or miliolid tests, but no such grains were recognized in this study. the absence of these characteristic foraminifera lead to the conclusion that the bioclastic detritus came from synchronous outer-ramp environments that were attached to the istrian flysch basin from the south. however, there is also the figure 16. two possible options of schematic reconstructions of the istrian foredeep basin after megabed deposition. (a) all megabeds are related to extensional tectonics and normal faulting in the distal foredeep. (b) proximal megabeds are related to compressional tectonics and reverse faulting in front of the dinaric orogenic wedge. not to scale. see discussion in the text. g eologia c roatica 113petrinjak et al.: megabeds in istrian flysch as markers of synsedimentary tectonics within the dinaric foredeep (croatia)petrinjak et al.: megabeds in istrian flysch as markers of synsedimentary tectonics within the dinaric foredeep (croatia) possibility that some bioclasts originally originated from the outer ramps are derived from semi-consolidated (uncemented) clayey limestones from the collapsed succession along the foredeep slope. 6.3. interpretation of the internal divisions and comparison with previous works as far as sedimentary processes are concerned, the megabeds may be considered as complex beds which were deposited by a range of sedimentary processes e.g., submarine rock avalanche, debris flow, and high-density turbidity currents. as mentioned earlier, the distinct bipartite organization is a consequence of the flow transformations from debrite flow to turbidity current (hampton, 1972; lowe, 1982; mulder & alexander, 2001; shanmugam, 2006). this distinct architecture can be related to beds with similar internal organization. comparison with hybrid event beds (haughton et al. 2003, 2009; talling, 2013) indicates that the bipartite megabeds described in this study are lacking the basal layer that is present in tripartite hybrid beds, and are much thicker than the described hybrid event beds in papers by haughton et al., (2003, 2009) and talling (2013). the division i facies types described here bear comparison with the divisions of megabeds from the published literature. the megabeds described in amy et al. (2007) from the pïera cava basin (se france) are very similar to the istrian megabeds described in this research and the authors differentiate two facies types within coarse-grained beds facies f1: cohesive debris-flow deposit comprised of poorly sorted, metre-long clasts and a significant proportion of muddy matrix; and facies f2: clastrich debris-flow deposits with a minor proportion of cohesive matrix. the carbonate megaturbidites described by labaume et al. (1987) from the eocene hecho group (sw-pyrenean foreland basin, spain) are up to 200 m thick and composed of a megabreccia unit in the lower part and the turbidite in the upper part. the megabreccia unit is subdivided into separate divisions: a largely clast supported and poorly organized breccia (division i) and carbonate breccia which contains an abundance of rip-up clasts of slope marlstone and basin plain turbidites (division ii). tunis & venturini (1992) describe megabeds in the julian basin as couplets of megabreccia in the lower part and a graded calcarenite and marl in the upper part. the described vertical sections of megabeds is further subdivided into two megabreccia units and three turbidite units. unit l is a megabreccia which mainly consists of big blocks of shallow water limestone olistoliths. unit 2 is also carbonate megabreccia, but can be recognized by the lack of large limestone olistoliths, for the numerous discshaped clasts of calcareous mudstone and for the rip-up siliciclastic turbidites with some interbedded calciturbidites. payros et al. (1999) recognized a downcurrent change in megabed composition from immature, homogeneous debrite in the proximal part, a differentiated, two-storey bipartite debrite and a turbidite in the middle part, and a base-missing debrite overlain by turbidite, or even a turbidite alone, in the distal part. the megabeds containing bipartite breccia outcrops show that each unit consists of a figure 17. geological map showing palaeotransport directions in the eocene istrian flysch. the palaeotransport direction data are taken from magdalenić (1972), marinčić et al. (1996) and babić & zupanič (1996). g eo lo gi a c ro at ic a 114 geologia croatica 74/2 clast-supported breccia overlain by a mud-supported breccia and then capped with a graded calcarenite. to recapitulate, the authors labaume et al. (1987); tunis &venturini (1992); payros et al. (1999) describe two subdivisions within a lower, debrite unit: clast supported breccia with olistoliths in the lower part and mud supported breccia containing mudstone rip-up clasts in the upper part. these subdivisions are roughly similar to the facies a and facies b described here within division i. however, within the studied megabeds of the istrian flysch, vertical differentiation of facies within division i itself is not recognized. the division i breccia at kaldir was probably deposited in the early stage of a mass transport event, probably a submarine rock avalanche or some other large-scale grain flow. the dynamic classification of mass transport deposits and evolutionary relationships among the processes responsible for sub-unit formation, from slide/slump and turbidity currents as end-members of such a broad spectrum are described by shanmugam (2006), festa et al. (2019) and ogata et al. (2020). however, the submarine rock avalanche deposits are rarely mentioned in the sediment mass transport spectrum so the exact mechanism of the kaldir megabed deposition is not yet clear. hagn et al. (1979) described the gračišće olistostrome as containing up to 1 cubic metre sized cretaceous and palaeogene boulders, smaller fragments of grey shale and a very rich fossil fauna that lived in the environment of the carbonate shelf. the authors (hagn et al., 1979) assumed that the fauna and olistoliths originated from different sides of the basin, and that they were resedimented by separate mechanisms and mixed only in-situ, during the final sedimentation. this assumption cannot be maintained because all the biogenic detritus is evenly distributed in the debrite part, as a subordinate constituent of the marly matrix, mixed with larger limestone and marl clasts. also, the bioclastic detritus is the main constituent in the upper turbitdite part (division ii). 6.4. triggering mechanisms and depositional models the clast composition indicates that the detritus of each megabed was derived from a different part of the cretaceous to palaeogene neritic carbonate succession, as well as from the flysch itself, as marl clasts are observed in some megabeds. it can be assumed figure 18. a comparative figure showing simplified logs of all the megabeds. the major differences are in the structure of the division i breccia – deposited by either a mudor clastdominated debris flow, or a submarine avalanche. also, note that each division i breccia is characterized by a specific composition (fig. 3). g eologia c roatica 115petrinjak et al.: megabeds in istrian flysch as markers of synsedimentary tectonics within the dinaric foredeep (croatia) that the synsedimentary faults that generated submarine failures formed along the carbonate ramps within the fast evolving distal foredeep (cf. sinclair, 1997; barnolas & teixell, 1994, fig. 16). the faulting also led to the exposure of the older carbonates along the fault scarps thus exposing them to erosion along the steep slopes. the slope collapses, eventually occurring along the fault scarps, generated the mass flows which transported the large quantities of carbonate material (both bioclastic detritus from synchronous carbonate ramps and clasts from older neritic limestones) from the scalloped scarps (figs. 2 and 16), and also reworked the autochthonous basinal marls. the earthquakes related to the tectonic evolution of the approaching dinaric orogen could have been the main triggering mechanism for the submarine collapses. the tectonic triggering mechanisms related to deposition of the megabeds in the perialpine foreland basins have already been documented and described (mutti et al., 1984; kleverlaan, 1987; pini et al 2012; ogata et al., 2020). tarlao et al. (1995) supposed that the ongoing orogenic deformation led to subaerial exposure of the basement carbonate succession. in this way the carbonate margins could have been weakened by subaerial processes and thus have been more prone to slope failures. if that was the case, the whole carbonate succession would have been karstified, both cretaceous and foraminiferal limestones. however, no karstified foraminiferal limestones were seen within the megabed clasts. this brings us to the conclusion that the only period of emergence and subaerial exposure was prior to deposition of the foraminiferal limestones, the upper cretaceous to palaeogene forebulge stage as described by otoničar (2007) and korbar (2009). furthermore, the studied megabeds are located randomly in the stratigraphy, without any precursive or successive facies associations, suggesting a seismically triggered slope collapse. in other cases, they would occur within major changes in sedimentation patterns, such as at the base of a coarse-grained fan as in the middle dalmatian basin, where deposition of the megabeds is attributed to periods of accelerated sea-level rise (marjanac, 1996). in the middle dalmatian basin, megabeds have been related to accelerated sea-level rise sometime after a lowstand, since they are interbedded with fan deltas (marjanac, 1996) which is not the case with the istrian megabeds. although the connection between global sea level change and deposition of the istrian megabeds is not yet established, a possible sea level drop during the middle eocene could have had an impact on resedimented carbonates in istria. time correlation between the istrian megabeds and global sea level data (e.g. haq et al., 1987) is not yet possible, since the available data about the megabeds age is too imprecise. moreover, the megabeds are present in various stratigraphic parts of the istrian flysch. the kaldir, šublentica, and hum occurrences (fig. 2) are positioned in the lower part of the istrian flysch succession while those at gračišće, plomin, and koromačno (fig. 2) are in the middle, and thus were probably deposited during various sea level stands. thus, the collapse events are more probably related to tectonic activity than to a specific sea level stand (fig. 16). the diverse influence of tectonics on the sediment deposition in foreland basins has been documented at various locations in the literature (kleverlaan, 1987; barnolas & teixell, 1994; payrose et al., 1999; tomasso & sinclair, 2014; gobo et al., 2021). although we concluded that depositions of the megabeds are mainly induced by tectonics, it is not yet clear if collapses that generated mass flows are rather related to normal faulting within the distal part of the foredeep basin (fig. 16a) or also to thrust faulting in the proximal part, i.e., in front of the orogenic wedge (fig. 16b). during the evolution of the istrian foreland basin the normal faults could have dissected the distal foredeep and even generated intrabasinal topographic highs (horsts) and in that way exposed the older rocks along the fault scarps (fig. 16a). also, the backstepping and retreat of the carbonate platforms, located in the distal parts of the foreland basin, could induce the collapse of platform margins as described in the jaca basin, and pyrennian foreland (barnolas & teixell, 1994). the alternative option is that some megabeds, at least the most proximal location of hum, are related to aborted thrust faults in front of the orogenic wedge (fig. 16b). 7. conclusions based on the data presented here, several concluding remarks can be made about the istrian megabeds. megabeds in the middle eocene istrian flysch are considered to represent single event bipartite mass transport deposits with a complex structure that implies a complex flow mechanism and flow transformations. the lower parts of the megabed (division i) are composed of debris flow deposits or even rock avalanche deposits (kaldir). the upper part (division ii) is composed of turbidity current deposits. the megabeds are composed of: a) lithoclasts derived from older neritic limestones underlying the flysch; b) bioclastic sediments derived from synchronous carbonate ramps, and c) reworked basinal sediments (predominantly hemipelagic marls). in addition to different structural features, each megabed has a distinct clast composition (lower and upper cretaceous limestones as well as the eocene foraminiferal limestones) indicating that each bed is a sedimentary record of a specific local slope failure that scalloped a different part of the cretaceous to palaeogene carbonate succession underlying the flysch. thus, each described megabed probably represents a separate local collapse within the dinaric foredeep. the synsedimentary faults dissected the floor of the evolving distal dinaric foredeep and exposed the basement rocks along the submarine fault scarps. seismic shocks related to the approaching orogen are proposed as the main triggering mechanism for the collapses along the fault scarps and/or oversteepened slopes. acknowledgement the research is partly based on the results of the mapping project for the basic geological map of the republic of croatia in scale 1:50.000 and scientific research within project geosekva (grant no. ip-2016-06-1854) funded by the croatian science foundation. special thanks to lara wacha for suggestions during the writing of the manuscript, and ladislav fuček for helping with the determinations of the cretaceous limestones. also, the authors would like to thank holcim croatia for the hospitality at their quarry at koromačno. kei ogata, marco patacci and two anonymous reviewers significantly contributed to the improvement of an earlier version of this manuscript. references abbate, e., bortolotti, v. & passerini, p. (1970): olistostromes and olistoliths.– in: sestini, g. (ed.): development of the northern apennines geosyncline: sedimentary geolology, 4, 521–557. amy, l., kneller, b. & mccaffrey, w. (2007): facies architecture of the grès de peïra cava, se france: landward stacking patterns in ponded turbiditic basins.– journal of the geological society, 164/1, 143–162. doi: 10.1144/0016-76492005019 g eo lo gi a c ro at ic a 116 geologia croatica 74/2 aubouin, j., blanchet, r., cadet, j.-p., celet, p., charvet, j., chorowicz, j., cousin, m. & rampnoux, j-p. (1970): essai sur la geologie des dinarides.– bulletin de la société géologique de france, 12/6, 1060–1095. babić, lj. & zupanič, j. (1983): paleogene clastic formations in northern dalmatia.− in: babić, lj. & jelaska, v. (eds.): contributions to sedimentology of some carbonate and clastic units of the coastal dinarides, excursion guidebook. international association of sedimentologists 4th regional meeting, split, 37–61. babić, lj., & zupanič, j. (1996): coastal dinaric flysch belt: palaeotransport model for the pazin basin, and the role of a foreland uplift.– natura croatica, 5, 317–327. babić lj., hernitz-kučenjak, m., ćorić, s. & zupanič, j. (2007): the middle eocene age of the supposed late oligocene sediments in the flysch of the pazin basin (istria, outer dinarides).– natura croatica: periodicum musei historiae naturalis croatici, 16/2, 83–103. barattolo, f., bassi, d. & romano, r. (2007): upper eocene larger foraminiferal–coralline algal facies from the klokova mountain (southern continental greece).– facies, 53, 361–375. doi: 10.1007/s10347-007-0108-2 barnolas, a. & teixell, a. (1994): platform sedimentation and collapse in a carbonate-dominated margin of a foreland basin (jaca basin, eocene, south pyrenees).– geology, 22/12, 1107–1110. doi: 10.1130/0091-7613(1994)022<1107:ps acia>2.3.co;2 bassi, d. (2005): larger foraminiferal and coralline algal facies in an upper eocene storm-influenced, shallow water carbonate platform (colli berici, northeastern italy).– palaeogeography palaeoclimatology palaeoecology, 226/17, 17–35. doi: 10.1016/j.palaeo.2005.05.002 benić, j. (1991): the age of the istria flysch deposits based on calcareous nannofosils.– in: drobne, k. & pavlovec, r. (eds.): introduction to the paleogene sw slovenia and istria. field-trip guidebook igcp project, early paleogene benthos, 2nd meeting postojna (slovenia, istria), p. 25. bergant, s., tišljar, j. & šparica, m. (2003): eocene carbonates and flysch deposits of the pazin basin.– in: vlahović, i. & tišljar, j. (eds.): field trip guidebook 22nd ias meeting of sedimentology – opatija 2003, 57–63. bergant, s., matičec, d., fuček, l., palenik, d., korbar, t., šparica, m., koch, g., galović, i. & prtoljan, b. (2020): basic geological map of the republic of croatia scale 1:50.000, sheet: rovinj 2– department of geology, croatian geological survey, zagreb. bosence, d.w.j. (2005): a genetic classification of carbonate platforms based on their basinal and tectonic settings in the cenozoic.− sedimentary geology, 175/1–4, 49–72. doi: 10.1016/j.sedgeo.2004.12.030 bouma, a.h. (1987): megaturbidite: an acceptable term?– geo-marine letters, 7, 63–67. doi: 10.1007/bf02237985 croatian geological survey (2009): geological map of the republic of croatia at the scale 1:300. 000.– croatian geological gurvey, department of geology, zagreb. ćorić, s., babić, lj., hernitz kučenjak, m. & zupanič, j. (2008): conflicting dating of the coastal dinaric flysch, and implications: eocene or miocene? the case of north dalmatia and istria.– geophysical research abstracts, p. 10. ćosović, v., drobne, k. & moro, a. (2004): paleoenvironmental model for eocene foraminiferal limestones of the adriatic carbonateplatform (istrian peninsula).– facies, 50, 61–75. ćosović, v., marjanac, t., drobne, k. & moro, a. (2008): outer dinarides: eastern adriatic coast. paleogene and neogene.− in: mccann, t. (ed.): the geology of central europe, volume 2: mesozoic and cenozoic. the geological society london, london, 1031–1139. ćosović, v., mrinjek, e, nemec, w., španiček, j. & terzić, k. (2018): development of transient carbonate ramps in an evolving foreland basin.– basin research, 30, 746–765, doi: 10.1111/bre.12274 drobne, k. (1977): alvéolines paléogènes de la slovénie et de l’istrie.– mémoires suisses de paléontologie, 99, 174 p. dunham, r.j. (1962): classification of carbonate rocks according to depositional texture.– in: ham, w.e. (ed.): classification of carbonate rocks. american association of petroleum geologists memoir, 1, 108–121. embry, a.f. & klovan, j.e. (1971): a late devonian reef tract on northeastern banks island, n.w.t.– bulletin of canadian petroleum geology, 19/4, 730–781. fallgatter, c., kneller, b., paim, p.s. & milana, j.p. (2016): transformation, partitioning and flow–deposit interactions during the run-out of megaflows.– sedimentology, 64/2, 359–387. doi: 10.1111/sed.12307 felix, m., leszczyński, s., slaczka, a., uchman, a., amy, l. & peakall, j. (2009): field expressions of the transformation of debris flows into turbidity currents, with examples from the polish carpathians and the french maritime alps.– marine and petroleum geology, 26/10, 2011–2020. doi: 10.1016/j.marpetgeo.2009.02.014 festa, a., pini, g. a., ogata, k. & dilek, y. (2019): diagnostic features and fieldcriteria in recognition of tectonic, sedimentary and diapiric mélanges in orogenic belts and exhumed subduction-accretion complexes.– gondwana research, 74, 7–30. doi: 10.1016/j.gr.2019.01.003 flügel, e. (2004): microfacies of carbonate rocks: analysis, interpretation and application.– springer-verlag, berlin, 976 p. doi: 10.1017/s0016756806221940 gobo, k., mrinjek, e. & ćosović, v. (2021): mass-transport deposits and the onset of wedge-top basin development: an example from the dinaric foreland basin, croatia.– journal of sedimentary research, 90/11, 1527–1548. doi: 10.2110/ jsr.2019.192 hagn, h., pavlovec, r. & pavšić, j. (1979): excursion g, gračišće near pićan, istria-eocene.– in: excursions guidebook, 16. european micropalaeontological colloquium, ljubljana, 185–190. hallock, p. & glenn, e.c. (1986): larger foraminifera: a tool for paleoenvironmental analysis of cenozoic carbonate depositional facies.– palaios, 1/1, 55–64. doi: 10.2307/3514459 hampton, m.a. (1972): the role of subaqueous debris flow in generating turbidity currents.– journal of sedimentary research, 42/4, 775–793. doi: 10.1306/74d7262b-2b21-11d7-8648000102c1865d haughton, p., barker, s. & mccaffrey, w. (2003): ‘linked’ debrites in sand‐ rich turbidite systems ‐ origin and significance.– sedimentology, 50/3, 459–482. doi: 10.1046/j.1365-3091.2003.00560.x haughton, p., davis, c., mccaffrey, w. & barker, s. (2009): hybrid sediment gravity flow deposits – classification, origin and significance.– mar. petroleum geology, 26/10, 1900–1918. doi: 10.1016/j.marpetgeo.2009.02.012 haq, b., hardenbol, j.r. & vail, p. (1987): chronology of fluctuating sea levels since the triassic.– science, 235/4793, 1156–67. doi: 10.1126/science.235.4793.1156 juračić, m. (1980): depth of sedimentation of marl with crabs estimated from the ratio between planktonic and benthic foraminifera.– geološki vjesnik, 31, 61–67. kleverlaan, k. (1987): gordo megabed: a possible seismite in a tortonian submarine fan, tabernas basin, province almeria, southeast spain.– sedimentary geolology, 51/3–4, 165–180. doi: 10.1016/0037-0738(87)90047-9 korbar, t. (2009): orogenic evolution of the external dinarides in the ne adriatic region: a model constrained by tectonostratigraphy of upper cretaceous to paleogene carbonates.– earth-science reviews, 96/4, 296–312. doi: 10.1016/j.earscirev.2009.07.004 krašeninnikov, v.a., muldini-mamužić, s. & džodžo-tomić, r. (1968): signification des foraminiferes planctoniques pour la division du paléogene de la yougoslavie et comparaison avec les autres régions examinées.– geološki vjesnik, 21, 117–145. labaume, p., mutti, e. & seguret, m. (1987): megaturbidites: a depositional model from the eocene of the sw-pyrenean foreland basin, spain.– geo-marine letters, 7/2, 91–101. doi: 10.1007/bf02237988 lowe, d.r. (1982): sediment gravity flows: ii depositional models with special reference to the deposits of high-density turbidity currents.– journal od sedimentary petrology, 52/1, 279–297. doi: 10.1306/212f7f31-2b24-11d78648000102c1865d magaš, n. (1973): osnovna geološka karta sfr jugoslavije, 1:100000, tumač za list cres l33-113, [basic geological map of sfry 1:100.000, geology of the cres sheet – in croatian, english abstr.].– institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd, 42 p. magdalenić, z. (1972): sedimentologija fliških naslaga srednje istre [sedimentology of central istria flysch deposits – in croatian, english abstr.].– prirodoslovna istraživnja, knjiga, 39, 71–100. marinčić, s. (1981): eocenski fliš jadranskog pojasa [eocene flysch of adriatic area – in croatian, english abstr.].– geološki vjesnik, 34, 27–38. marinčić, s., šparica, m., tunis, g. & uchman, a. (1996): the eocene flysch deposits of the istrian peninsula in croatia and slovenia. regional, stratigraphic, sedimentological and ichnological analysis.– annales, 9, 139–156. marjanac, t. (1990): reflected sediment gravity flows and their deposits in flysch of middle dalmatia, yugoslavia.– sedimentology, 37/5, 921–929. marjanac, t. (1991): importance of megabeds for reconstruction of paleogene flysch basin in split hinterland (middle dalmatia).– geološki vjesnik, 44, 201–213. marjanac, t. (1993): evolution of eocene–miocene flysch basin of central dalmatia, croatia.– unpubl. phd thesis, university of zagreb, 348 p. marjanac, t. (1996): deposition of megabeds (megaturbidites) and sea-level change in a proximal part of eocene-miocene flysch of central dalmatia (croatia).– geology, 24/6, 543–546. doi: 10.1130/0091-7613(1996)024<0543:dommas>2.3. co;2 marjanac, t. & ćosović, v. (2000): tertiary depositional history of eastern adriatic realm.– vijesti hrvatskog geološkog društva, 37/2, 93–103. matičec, d., vlahović, i., velić, i. & tišljar, j. (1996): eocene limestones overlying lower cretaceous deposits of western istria (croatia): did some parts of present istria form land during the cretaceous?– geologia croatica, 49/1, 117–127. mikes, t. & báldi-beke, m. & kazmer, m. & dunkl, i. & eynatten, h. (2008): calcareous nannofossil age constraints on miocene flysch sedimentation in the outer dinarides (slovenia, croatia, bosnia-herzegovina and montenegro).– g eologia c roatica 117petrinjak et al.: megabeds in istrian flysch as markers of synsedimentary tectonics within the dinaric foredeep (croatia)petrinjak et al.: megabeds in istrian flysch as markers of synsedimentary tectonics within the dinaric foredeep (croatia) geological society, london, special publications, 298, 335–363. doi: 10.1144/ sp298.16 mulder, t. & alexander, j. (2001): the physical character of subaqueous sedimentary density flow and their deposits.– sedimentology, 48/2, 269–299. doi: 10.1046/j.1365-3091.2001.00360.x mutti, e., ricci lucchi, f., seguret, m. & zanzucchi, g. (1984): seismoturbidites: a new group of resedimented deposits.– marine geology, 55/1–2, 103–116. doi: 10.1016/0025-3227(84)90135-x ogata, k., pogačnik, ž., pini, g.a., tunis, g., festa, a., camerlenghi, a. & rebesco, m. (2014): the carbonate mass transport deposits of the paleogene friuli basin (italy/slovenia): internal anatomy and inferred genetic processes.– marine geology, 356, 88–110. doi: 10.1016/j.margeo.2014.06.014 ogata, k., pogačnik, ž.,tunis, g., pini, g.a., festa, a. & senger, k. (2019): a geophysical-geochemical approach to the study of the paleogene julian–slovenian basin “megabeds” (southern alps–northwestern dinarides, ita ly/ slovenia).– geosciences, 9/4, 1–17. doi: 155. 10.3390/geosciences9040155 ogata, k., festa, a., pini, g.a. & alonso, j.l. (2020): submarine landslide deposits in orogenic belts: olistostromes and sedimentary mélanges in submarine landslides.– in ogata, k., festa, a. & pini, g.a. (eds): submarine landslides: subaqueous mass transport deposits from outcrops to seismic profiles, geophysical monograph 246, american geophysical union. john wiley & sons, 3–26. doi: 10.1002/9781119500513.ch1 otoničar, b. (2007): upper cretaceous to paleogene forbulge unconformity associated with foreland basin evolution (kras, matarsko podolje and istria; sw slovenia and nw croatia).– acta carsologica, 36/1, 101–120. doi: 10.3986/ac.v36i1.213 payros, a., pujalte, v. & orue-etxebarria, x. (1999): the south pyrenean eocene carbonate megabreccias revisited: new interpretation based on evidence from pamplona basin.– sedimentary geology, 125/3–4, 165–194. doi: 10.1016/ s0037-0738(99)00004-4 piccoli, g. & proto decima, f. (1969): ricerche biostratigrafiche sui depositi flyschoidi della regione adriatica settentrionale e orientale.– memorie degli instituti di geologia mineralogia dell’universitŕ di padova, 27, 1–23. pini, g.a., ogata, k., camerlenghi, a., festa, a., lucente, c.c. & codegone, g. (2012): sedimentary melanges and fossil mass‐transport complexes: a key for better understanding submarine mass movements?– in: yamada, y., kawamura, k., ikehara, k., ogawa, y., urgeles, r., mosher, d., chaytor, j. & strasser, m. (eds.): submarine mass movements and their consequences, advances in natural and technological hazards research, 31, dordrecht, springer science+businessmedia b.v., 585–594. doi: 10.1007/978-94007-2162-3_52 polšak, a. & šikić, d. (1973): osnovna geološka karta sfr jugoslavije, 1:100000, tumač za list rovinj l30-100, [basic geological map of sfry 1:100.000, geology of the rovinj sheet – in croatian, english abstr.].– institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd, 51 p. rasser, m.w., & piller w.e. (2004): crustose algal frameworks from the eocene alpine foreland.–palaeogeography, palaeoclimatology, palaeoecology, 206/1–2, 21–39. doi: 10.1016/j.palaeo.2003.12.018 schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpinecarpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss journal of geosciences, 101, 139–183. doi: 10.1007/s00015-008-1247-3 shanmugam, g. (2006): deep-water processes and facies models: implications for sandstone petroleum reservoirs: amsterdam, elsevier.– handbook of petroleum exploration and production, 5, 476 p. sinclair, h.d. (1997): tectonostratigraphic model for underfilled peripheral foreland basins.– gsa bulletin, 109/8, 324–346. doi: 10.1130/0016-7606(1997)109<0324:tmfupf>2.3.co;2 šikić, d. & polšak, a. (1973): osnovna geološka karta sfr jugoslavije, 1:100000, tumač za list labin l33-101 [basic geological map of sfry 1:100.000, geology of the labin sheet – in croatian, english abstr.].– institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd, 55 p. šikić, d. & pleničar, m. (1975): osnovna geološka karta sfr jugoslavije, 1:100000, tumač za list ilirska bistrica l33-89 [basic geological map of sfry 1:100.000, geology of the ilirska bistrica sheet – in croatian, english abstr.].– institut za geološka istraživanja, zagreb, geološki zavod. ljubljana, savezni geološki zavod, beograd, 51 p. špelić, m., del ben, a. & petrinjak, k. (2021): structural setting and geodynamics of the kvarner area (northern adriatic).– marine and petroleum geology, 125, 104857. doi: 10.1016/j.marpetgeo.2020.104857 talling, p. (2013): hybrid submarine flows comprising turbidity current and cohesive debris flow: deposits, theoretical and experimental analyses, and generalized models.– geosphere, 9, 460–488. doi: 10.1130/ges00793.1 tarlao, a., tunis, g. & venturini, s. (1995): lutetian transgression in central istria: the rogovići-mećari section case.– in: vlahović, i., velić, i. & šparica, m. (eds): proceedings 2, first croatian geological congress. institute of geology, zagreb, 613–618. tarlao, a., tunis, g. & venturini, s. (2005): dropstones, pseudoplanktonic forms and deep-waterdecapod crustaceans within a lutetian condensed succession of central istria (croatia): relation to palaeoenvironmental evolution and palaeogeography.– palaeogeography, palaeoclimatology, palaeoecology, 218/3–4, 325–345. doi: 10.1016/j.palaeo.2004.12.023 tomasso, m. & sinclair, h. (2004): deep-water sedimentation on an evolving fault-block: the braux and st benoit outcrops of the grès d’annot.– geological society, london, special publications, 221, 267–283. doi: 10.1144/gsl. sp.2004.221.01.14 tunis, g. & venturini, s. (1992): evolution of the southern margin of the julian basin with emphasis on the mega beds and turbidites sequence of the southern julian prealps (ne italy).– geologia croatica, 45, 127–150. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeography, palaeoclimatology, palaeoecology, 220/3–4, 333–360. doi: 10.1016/j.palaeo.2005.01.011 vlahović, i. & velić, i. (2009): liburnijske naslage, foraminiferski vapnenci i prijelazne naslage (?gornji paleocen, donji i srednji eocen –?pc, e1,2) [liburnian deposits, foraminiferal limestones and transitional beds (?upper paleocene, lower and middle eocene –?pc, e1,2 – in croatian].− in: velić, i. & vlahović, i. (eds.): tumač geološke karte republike hrvatske 1:300000 [explanatory notes of basic geological map of croatia 1:300.000 – in croatian]. hrvatski geološki institut, zagreb, 76−77. velić, i., tišljar, j., vlahović, i., matičec, d. & bergant, s. (2003): evolution of the istrian part of the adriatic carbonate platform from the middle jurassic to the santonian and formation of the flysch basin during the eocene: main events and regional comparison.– in: vlahović, i. & tišljar, j. (eds.): field trip guidebook – 22nd ias meeting of sedimentology – opatija. croatian geological survey, zagreb, 57–63. velić, i. (2007): stratigraphy and palaeobiogeography of mesozoic benthic foraminifera of the karst dinarides (se europe).– geologia croatica, 60/1, 1–113. živković, s. & babić, lj. (2003): paleoceanographic implications of smaller benthic and planktonic foraminifera from the eocene pazin basin (coastal dinarides, croatia).– facies, 49, 49–60. doi: 10.1007/s10347-003-0024-z živković, s. & glumac, b. (2007): paleoenvironmental reconstruction of the middle eocene trieste-pazin basin (croatia) from benthic foraminiferal assemblages.– micropaleontology, 53/4, 285–310. doi: 10.2113/gsmicropal.53.4.285 g eo lo gi a c ro at ic a 118 geologia croatica 74/2 plate 1. photomicrographs of the microfacies of the most common clasts from division i breccia (a, b, c, e, f, and g) and microfacies of bioclastic material form division ii (d and h) of the šublentica and hum sections. a – nummulitid-alveolinid packstone-grainstone showing the association of alveolinids (a), nummulitids (b) and miliolid (c). sample šub-7. middle eocene. šublentica section; b – peloid-miliolid packstone-grainstone showing miliolids (a) and peloids (b). sample šub-43, middle cretaceous (albian-cenomanian). šublentica section; c – orthophragminid wackestone showing ortophragminid test (a) with other bioclastic detritus. sample šub-43. middle eocene. šublentica section; d – densely packed, well-sorted foraminiferal calcirudite showing large benthic foraminifera tests (mostly orthophragminids and nummulites), red algae (rodoliths), mudstone lithoclasts, and biodetritus (fragments of large benthic foraminifera, encrusting foraminifera, and echinoderms). sample šub-ii 3. middle eocene. šublentica section; e – foraminiferal wackestone showing palorbitolina lenticularis (blumenbach, 1805). sample hum–123. lower cretaceous (lower aptian). hum section; f – nummulitid-alveolinid grainstone showing an association of alveolinids (a), nummulitids, (b), asillina sp., and orbitolites sp. (c). sample hum 85. middle eocene. hum section; g – foraminiferal wackestone showing the recrystallized transversal section of cenomanian foraminifera broeckina (pastrikella) balcanica (cherchi, radoičić & schroeder, 1976). sample hum–286. upper cretaceous. hum section; h – densely packed, well-sorted foraminiferal calcirudite showing fragmented large benthic foraminifera tests (mostly discocyclines/orthophragminids, nummulites, and unidentified rotaliid foraminifera), red algae, and biodetritus. sample hum 3b. middle eocene hum section. g eologia c roatica 119petrinjak et al.: megabeds in istrian flysch as markers of synsedimentary tectonics within the dinaric foredeep (croatia) plate 2. photomicrographs of the microfacies of the most common clasts from division i breccia (a, b, c, e, f, and g) and the microfacies of bioclastic material form division ii (d and h) of kaldir and gračišće sections. a – laminated peloidal wackestone-packstone with rare ostracods. sample k-132. upper cretaceous (cenomanian). kaldir section; b – ostracodal mudstone-wackstone, showing ostracods (a), recrystallized thaumatoporella sp. (b) and aeolisacus sp. (c). sample k-152. upper cretaceous. kaldir section; c – foraminiferal wackestone-floatstone showing nummulitids (a), red algae – rodoliths (b), red algal crusts (c), echinoderm fragment (d) and orthophragminides (e). sample k-num. middle eocene. kaldir section; d – densely packed, well-sorted foraminiferal calcarenite showing large benthic foraminifera tests (mostly orthophragminids and nummulites), red algae (corallinacea) and biodetritus fragments of foraminifera, echinoderms, bryozoans and bivalves. sample kaldir 1a. middle eocene. kaldir section; e – algal wackestone showing red algae framework (a), nummulitids (b), and unidentified bioclastic detritus. sample gr-199. middle eocene. gračišće section; f – densely packed, well-sorted foraminiferal calcarenite showing large benthic foraminifera tests (mostly orthophragminids and nummulites), red algae crusts, and other biolastic detritus (fragments of large benthic foraminifera, encrusting foraminifera and echinoderms) and mudstone-wackeston lithoclasts. sample gračišće-1. middle eocene. gračišće section. g eo lo gi a c ro at ic a 120 geologia croatica 74/2 plate 3. photomicrographs of the microfacies of the most common clasts from division i breccia (a, c, d, and e) and microfacies of bioclastic material form division ii (b and f) of plomin and koromačno sections. a – algal wackestone showing red algae (a) encrusting coral fragments (b) and other unidentified bioclasts. sample pl-ii 123. middle eocene. plomin section; b – alveolinid packstone-grainstone showing association of alveolinids (a), miliolids (b), and orbitolites sp. fragment (c). sample pl ii-124. middle eocene. plomin section; c – foraminiferal-algal bindstone showing red algae encrusting mudstone lithoclasts and unidentified bioclast. sample pl-ii 87. middle eocene. plomin section; d – densely packed, well-sorted foraminiferal calcirudite showing large benthic foraminifera test (mostly orthophragminids and nummulites), biodetritus of red algae, and a skeletal wackestone lithoclast. sample pl-3. middle eocene. plomin section; e – alveolinid grainstone showing association of alveolinids (a), nummulitids (asillina sp.), b) and orbitolites sp (c). sample kor ii 112. middle eocene. koromačno section; f – bioclastic-algal wackestone with red algae framework (a) and bioclastic detritus. sample kor ii 162. middle eocene. koromačno section; g – algal wackestone showing red algae framework (a), corals (b), and bioclastic detritus. sample kor ii 179. middle eocene. koromačno section; h – densely packed, well sorted foraminiferal calcirudite showing large benthic foraminifera tests (mostly discocyclines/orthophragminids and nummulites), red algae (corallinacea), and biodetritus (fragments of large benthic foraminifera, encrusting foraminifera, and echinoderms). sample kor ii ka1. middle eocene. koromačno section. 2019 | 72/1 | 1– 4 | 6 figs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the palaeozoogeographic zonation of ancient oсeans and continents is one of the main methods of comparative palaeobiogeography. at the beginning of the last century, general scientific works of haug (1908–1911) were devoted to this study. patterns of the biogeographic distribution of palaeobasins of different geological ages along with the principles of palaeozoogeographical zonation have been highlighted in the works of, among others, makridin & katz, (1966), makridin (1973, 1982, 1983), westermann (2000), cessa & westermann (2003), and mamedalizade (2011). a description of the palaeontological materials of sea urchins of the late cretaceous of the caucasus and the stratigraphic distribution of many species were widely covered in the works of moskvin (1949), poslavskaya & moskvin (1959), rengarten (1959), gambashidze (1967), gongadze (1979), moskvin (1986), khalilov & melikov (1988), melikov (2002, 2005), mamedalizade (2005). the upper cretaceous deposits of the caucasus are characterized by a rich diversity of fossils, of which the class echinoidea is well represented. the systematic composition and zoogeography of the sea urchins of the late cretaceous of this region have been relatively poorly studied. in this context, an attempt is made to highlight some issues concerning the distribution of late cretaceous sea urchins of cenomanian, turonian, cogniacian and santonian ages from the caucasus on the basis of the collected specimens and published data in the literature. 2. materials the basis of this study is the author’s own collections from upper cretaceous sediments collected during numerous field expeditions in the caucasus. in all, about 900 specimens of sea urchin skeletons belonging to the echinoneoida, diadematoida, holasteroida, cassiduloida, spatangoida and clypeasteroida were collected from a wide range of ages. in this study, the classification scheme proposed by smith & kroh (2011) is followed. distribution of echinoids and palaeozoogeographic units of the cenomanian-santonian basins of the caucasus and mediterranean regions mamedalizade a.m. baku state university, faculty of geology, zahid halilov str. 23, az1148, baku, azerbaijan; (aladdin-mamedalizade@rambler.ru) doi: 10.4154/gc.2019.04 abstract based on the palaeontological materials of the cenomanian, turonian, coniacian and santonian in the caucasus, taxonomic composition, geographic distribution and migration routes of sea urchins are presented. furthermore the possibility of identifying zoogeographic units in the late cretaceous basins of the caucasus are discussed. 3. discussion in general, cenomanian sea urchins of the caucasus are not common. they are represented by few specimens as noted by poslavskaya & moskvin (1959). in the cenomanian stage, the sea urchins holectypus exciscus desor, h. cenomanensis guéranger, conulus laevis agassiz, nucleolites morrisi d’orbigny, catopygus columbaris (lamarck) and holaster subglobosus (leske) (fig. 1) existed in the marine basins of the azerbaijanian part of the lesser caucasus. the literature concerning the geographical distribution of these species is very scarce. in the cenomanian, the widest geographical area is shown by holaster subglobosus, the remains of which were also observed in the northern caucasus and the kopet-dag mountain range in the border region between turkmenistan and iran poslavskaya & moskvin (1959). in addition to this species, camerogalerus cylindrica lamarck also appears in cenomanian deposits of the northern caucasus. article history: manuscript received may 20, 2018 revised manuscript accepted october 31, 2018 available online february 15, 2019 keywords: late cretaceous, echinoids, palaeozoogeography, classification, lesser caucasus figure 1. a geographical distribution of sea urchins of the caucasus in the cenomanian. designations: (1) boundary of the mediterranean region; (2) sea; (3) land; echinoid genera: (4) holectypus;(5) conulus; (6) nucleolites; (7) catopygus; (8) holaster. g eo lo gi a c ro at ic a geologia croatica 72/12 according to gongadze (1979), cenomanian sea urchins of georgia are represented by the species discoides cf. subucula (klein), pyrina orbygniana (agassiz), p. cf. laevis (agassiz) and p. cf. tumida (gauthier). cenomanian sea urchins of the azerbaijanian part of the lesser caucasus, georgia and the northern caucasus differ sharply from one another with respect to their species composition. despite this, there is a general distribution of the species holaster subglobosus in the late cenomanian in both the lesser caucasus and the northern caucasus regions. by the end of the cenomanian, holectypus exciscus, h. cenomanensis, nucleolites morrisi, catopygus columbaris and conulus laevis cease to exist in the area of the lesser caucasus (azerbaijanian part). in the turonian, holaster subglobosus is replaced by h. planus mantell. the genus conulus is represented by a new species composition consisting of c. rhotomagensis (sismonda), c. ellipticus (zareczny), c. subconicus (d᾿orbigny), c. vulgaris (leske), c. djanelidzei gongadze and c. subrotundus (mantell). the turonian sea urchins of the lesser caucadus, c. rhotomagensis, c. ellipticus, c. subconicus, existed in the early turonian marine basin. in the second half of the turonian, together with holaster planus, representatives of both echinocorys (echinocorys sphaericus (schlüter), e. gravesi desor, e. gibbus (lamarck) and micraster (micraster leskei d᾿orbigny), are observed for the first time in this area. in the georgian part of the caucasus (the dzuril massif and the district of kutaisi) the genus pyrina ceases to exist at the end of the cenomanian and discoides cf. subucula (klein) is replaced by discoides minima agassiz, camerogalerus minimus agassiz. together with this species in the turonian, conulus vulgaris, c. subrotundus and hemiaster nucleus desor (gongadze, 1979) also appear for the first time in the dzuril massif. in the northern caucasus, during the transition from the cenomanian to the turonian, the species camerogalerus cylindrica (lamarck) disappears, and holaster subglobosus is replaced by h. planus. along with these species, eight completely new species of sea urchins appear within the genera conulus, echinocorys, infulaster and micraster in the turonian (poslavskaya & moskvin, 1959). all sea urchin species appearing in the turonian in the caucasus (with the exception of micraster subglobosus poslavskaya & moskvin) were first described from the late cretaceous of western europe. in the azerbaijanian part of the lesser caucasus, four echinoid species present in the turonian belong to the genus conulus. among these, only conulus subrotundus and c. subconicus have been recorded from the upper turonian deposits of georgia (gongadze, 1979) and the northern caucasus (poslavskaya & moskvin, 1959). conulus subrotundus and c. subconicus were distributed more widely ranging from the anglo – paris basin to the kopetdag mountains. the species conulus subrotundus, shifted its distribution in the second half of the turonian from west to east in the direction of the donbas, crimea, greater caucasus, mangystau peninsula in western kazakhstan, the lesser caucasus and the kopet-dag mountain areas. it is also known from both the lower and upper turonian deposits of england, france, germany, romania, belgium and poland (fig. 3). holaster planus, which has a wide geographical extent from western europe to the kopet-dag mountains, appeared in the second half of the turonian in the lesser caucasus and northern caucasus. it is a zonal species for the late turonian in the caucasus, the transcaspian area (eastern kazakistan and turkmenistan), and in europe. echinocorys sphaericus, which is of great stratigraphic importance for the upper turonian deposits of the donbas, crimea, caucasus, and the transcaspian, also had a wide geographical distribution. it was first recorded in lower turonian age deposits of england, france, belgium, poland, and migrated in the second half of the turonian period towards the carpathians, crimea, and then onwards to the northern caucasus, the mangystau peninsula and the lesser caucasus as well as the kopet-dag mountains. the turonian sea urchins of the lesser caucasus are similar in species composition to the sea urchins of western europe. their distribution indicates that, there was a broad middle european palaeozoogeographic region in both the cenomanian and the turonian. the composition of the sea urchins of the coniacian of the caucasus differs from that of the cenomanian and the turonian with respect to their generic and species composition. thus, the genera conulus, echinocorys and micraster, which existed in the basins of the lesser caucasus in the turonian, are represented in the coniacian by several new species. in addition, new genera of figure 3. the range of conulus subrotundus mantell in the turonian. designations: (1) boundary of the mediterranean region; (2) sea; (3) land; (4) early turonian; (5) late turonian; (6) dispersal direction. figure 2. a geographical distribution of genera of sea urchins of the caucasus in the turonian. designations: (1) boundary of the mediterranean region; (2) sea; (3) land; echinoid genera: (4) conulus; (5) holaster; (6) echinocorys; (7) micraster. g eologia c roatica mamedalizade a.m.: distribution of echinoids and palaeozoogeographic units of the cenomanian-santonian basins of the caucasus ... 3 cardiotaxis and isomicraster appear for the first time. in this stage in the marine basins of the lesser caucasus, the number of species of the genus conulus decreases from four to three. despite this fact, two new species, conulus ovulum lamarck and c. raulini cotteau occur along with c. subconicus. with the appearance of micraster coranguinum klein in the second half of the coniacian, the number of common species is eleven (fig. 4). in comparison with the azerbaijan part of the lesser caucasus, in the dzirul massif of georgia and northern caucasus, there was a significant reduction in sea urchin abundance during the transition from the turonian to the coniacian. in georgia, only conulus subconicus passes from the turonian into the coniacian (gongadze, 1979), together with c. subconicus and echinocorys gravesi desor (poslavskaya & moskvin, 1959) in the northern caucasus. in addition, two new species also appear in the northern caucasus; echinocorys vulgaris breynius and micraster coranguinum. the analysis of the sea urchin assemblages of the caucasus and the donetsk basin indicate that the connection between the boreal sea and neotethys which existed in the cenomanian and turonian continued to remain open throughout the coniacian. at that time, common species from the caucasus migrated from northern regions to the southern edges of the european palaeozoogeographic region (caucasus and transcaspian) through to the crimea peninsula. an example is the common presence of species of the donetsk basin (savchinskaya, 1974, 1982) with areas of the donbas, caucasus, and the transcaspian regions including conulus subconicus, e. gravesi, e. vulgaris, the early coniacian micraster cortestudinarium goldfuus and late coniacian m. coranguinum. a connection that existed in the coniacian, between the boreal sea and neotethys, was previously reported by tsagareli (1954), naidin (1964) and ali-zade (1972). these researchers believed that there was no climatic barrier between the boreal sea and neotethys, as many species of belemnites and inoceramid bivalves migrated from the north to the south and settled in the areas of both the greater and lesser caucasus. sea urchins of western european appearance (especially the central european ones) observed in the coniacian sediments of the caucasus once again indicate the lack of a climatic barrier between the boreal sea and neotethys and that many species could freely migrate from the north to south and from south to east. in deposits of santonian age of the lesser caucasus, sea urchins are represented by twelve species belonging to five genera (fig. 5). coniacian and santonian sea urchins are similar to one other (with ~ 60% of the total species). the coniacian genera conulus, cardiotaxis, echinocorys, micraster and isomicraster are present here along with a number of the new species. these are conulus albogalerus klein, c. oblongus d᾿orbigny, cardiotaxis mundus rengarten, echinocorys scutatus leske, micraster turonensis bayle, m. rostratus (mantell) and i̇somicrster senonensis (lambert). in addition, there are also three species that pass from the coniacian to the santonian including conulus raulini cotteau cardiotaxis maximus (schlüter) and micraster coranguinum. the analysis of both field observations and literature data shows that in the santonian marine basins of the lesser caucasus and northern caucasus, there were only two common species with micraster coranguinum and m. rostratus. despite this, the sea urchin fauna of santonian age of the caucasus had a wide geographic distribution ranging from western europe to the eastern margin of the kopet-dag mountains. conulus subconicus, echinocorys vulgaryis, micraster cortestudinarium (goldfuus) and m. coranguinum also show a wide geographical distribution. in the coniacian and santonian, these species existed in the marine basins of western europe, northern africa (algeria, tunisia) and along the southern edge of the european palaeozoogeographic region, while conulus albogalerus was able to figure 6. the range of echinocorys vulgaris breynius the coniacian and santonian. designations: (1) boundary of the mediterranean region; (2) sea; (3) land; (4) coniaсian; (5) santonian; (6) dispersal direction. figure 5. a geographical distribution of sea urchin of the caucasus in the santonian. designations: (1) boundary of the mediterranean region; (2) sea; (3) land; echinoid genera: (4) conulus; (5) cardiotaxis; (6) echinocorys; (7) isomicraster; (8) micraster. figure 4. a geographical distribution of sea urchin of the caucasus in the cogniacian. designations: (1) boundary of the mediterranean region; (2) sea; (3) land; echinoid range: (4) conulus; (5) cardiotaxis, (6) echinocorys; (7) micraster. g eo lo gi a c ro at ic a geologia croatica 72/14 migrate to northern india. echinocorys vulgaris first appeared in western europe in the coniacian, and in the santonian it migrated eastward to the donetsk basin, the crimea peninsula, the lesser caucasus, and the kopet-dag mountains (fig. 6). micraster rostratus and paronaster cupuliformis airaghi also had a wide geographical distribution from western europe to the eastern edge of kopet-dag mountains. paronaster cupuliformis first appears in the early campanian in the azerbaijanian part of the lesser caucasus. in georgia (according to gongadze, 1979) during the transition from the coniacian to the santonian, of the two coniacian species, conulus vulgaris goes extinct while, c. djanelidze passes into the santonian. along with representatives of the genus conulus, a new genus micraster appears, with two species (micraster cf. coranguinum and m. cf. rostratus) present for the first time. micraster coranguinum appeared in the lesser caucasus and northern caucasus even earlier in the second half of the coniacian. the santonian sea urchins of the northern caucasus, are relatively diverse compared to those of the earlier stages (poslavskaya & moskvin, 1959). among the coniacian species, only micraster coranguinum passes into the santonian. echinocorys gravesi is replaced by echinocorys turritus lambert, and the genus micraster is represented in the santonian by micraster heberti lacvivier and m. rostratus. together with these species, in the second half of the stage, new species occur in the northern caucasus, namely offaster pomeli munier-chalmas, paronaster cupuliformis airaghi and ornithaster sokolovi moskvin & poslavskaya (poslavskaya & moskvin, 1959). 4. conclusion the studied materials allow the following conclusions to be drawn: – the main part of the late cretaceous sea urchins of the caucasus were geographically widespread and a central european appearance; – there was no climatic barrier during the late cretaceous between the boreal seas and neotethys allowing for the relatively free migration of sea urchin faunas from central europe towards the south-east, to the southern edge of the european palaeozoogeographic region. references ali-zade, a.a (1972): cretaceous belemnites of azerbaijan [melovye belemnity azerbaidzhana – in russian].– moscow, nedra, 280 p. cessa, f. & westermann, g.e.g. (2003): towards a guide to palaeobiogeographic classification.– palaeogeography, palaeoclimatology, palaeoecology, 201/1– 2, 179–181. dzabarov, g.n. (1964): upper cretaceous sea urchins of central kopet dagh and their stratigraphical significance [verkhnemelovye morskie ezhi tsentralʹnogo kopetdaga i ikh stratigraficheskoe znachenie – in russian].– ashkhabad, turkmenstan, turkmenizdat, 164 p. gambashidze, r.a. (1967): some molluscs and echinoderms from the upper cretaceous deposits of georgia [nekotorye mollyuski i iglokozhye iz verchnemelovych otlozheniy gruzii – in russian].– georgia, tbilisi, works of the institute of geology of the academy of science of the georgian ssr, issue 15, 13–19. gongadze, g.s. (1979): the upper cretaceous echiniods of georgia and their stratigraphic value [pozdnemelovye echinoidei gruzii i ichstratigraficheskoe znachenie – in russian].– tbilisi, tbilisi st. univ., 218 p. haug, e. (1908-1911): traité de géologie. les périodes géologiques.– paris, france, armand colin, 2, 539–2024. khalilov, a.g. & melikov, o.g. (1988): sea urchins. [in melovaya fauna azerbajdzhana – in russian].– in: ali-zade, a.a. (eds.). baku, azerbaijan, elm, 184–213. makridin, v.p. & katz, y.i. (1966): some technique questions of palaeozoogeographic studies.– in: sokolov, b.s. (eds.): organizm and environment in the geological past [organism i sreda v geologicheskom proshlom – in russian].– moscow, russia, nauka, 98–115. makridin, v.p. (1973): principles for recognition and nomenclature of divisions of the palaeozoogeographic zonation of marine basins [prinsipy vydeleniya i nomenklatura podrazdelenij palaeozoogeograficheskogo rayonirovaniya morskich bassejnov – in russian].– palaeontol. zh., 2, 3–9. makridin, v.p. (1982): palaeobiogeography, its main directions and problems.– geology on the balkan peninsula, 46, 211–224. makridin, v.p. (1983): basic directions and problems of palaeobiogeography [iskopayemaya fauna i flora ukrainy – in russian].– in: sokolov, b.s. (eds.): materials of the third session of the ukrainian palaeontol soc. kiev, ukraina, 97–103. mamedalizade, a.m. (2005): to the stratigraphy of the deposits of the upper cretaceous in the vicinity of the village of bory [k stratigrafii otlozhenij verchnego mela v okrecnostyach sel. bory – in russian].– proceedings of national academy of science of azerbaijan, 2, 58–61. mamedalizade, a.m. (2011): palaeozoogeographic zonation of the campanian and maastrichtian marine basins of the caucasus and transcaspian.– palaeontologich. journ., 45/2, 154–158. melikov, o.g. (2002): the stratigraphical significance of echinoderms of the lesser caucasus [stratigraficheskoe znachenie iglokozhich malogo kavkaza (azerbaijan) – in russian].– baku, azerbaijan, nafta-press, 99 p. melikov, o.g. (2005): echinoderms of the mesozoiccenozoic deposits of the lesser caucasus and their stratigraphycal significance [iglokozhye mezozoy-kaynozoyskich otlozheniy malogo kavkaza i ich stratigraficheskoe znachenie – in russian].– abstract of the doctoral dissertation. baku, azerbaijan, nafta-press, 53 p. moskvin, m.m. et al. (1949). echinoidea [in atlas rukovodyashchie formy iskopaemykh faun sssr, nizhniy mel].– moscow, gosgeoltekhizdat, 9, 98–130. moskvin, m.m. (1986): regional stratigraphical essays: lesser caucasus. stratigraphy of the ussr: cretaceous system.– in – sokolov, b.s. (eds.). [regionalʹnye stratigraficheskye ocherki: malij kavkaz. stratigrafia sssr: melovaya sistema]. moskow, nedra, semi vol. 1, 238–251. naidin, d.p. (1964): upper cretaceous belemnites of the russian platform and adjacent areas: actinocamacs, gonioteuthis and belemnocamacs [pozdnemelovye belemnity russkoj platformy i sopredelʹnych oblastej: actinocamacsy, goniotejtisy i belemnocamacsy – in russian].– moskow, mosk. st. univ. publ. house, 190 p. poslavskaya, n.a. & moskvin, m.m. (1959): echinoderms.– in: moskvin, m.m. (eds.): in atlas of the upper cretaceous fauna of the northern caucasus and crimea [verkhnemelovoi fauny severnogo kavkaza i kryma]. moscow, gos. nauchno-tekhn. izd. neft. gornotopl. lit., 237–304. rengarten, v.p. (1959): stratigraphy of the cretaceous deposits of the lesser caucasus. regional stratigraphy of the ussr. [regionalʹnaya stratygrafiya sssr].– moskov, publishing house of the ussr academy science, 540 p. savchinskaya, o.v. (1974): echinoidea-sea urchins.– in: krimholts, e.y. (eds.): [echinoideamorskiye ezhi, in atlas verchnemelovoy faun donbassa].– moscow, nedra, 303–333. savchinskaya, o.v. (1982): conditions of the late cretaceous fauna of the donetsk basin [usloviya sushchestvovaniya pozdnemelovoj fauny donetskogo basseina].– moskow, nauka, 132 p. smith, a.b. & kroh, a. (editor) (2011): the echinoid directory. world wide web electronic publication. http://www.nhm.ac.uk/research-curation/projects/echinoiddirectory tsagareli, a.l. (1954): upper cretaceous of georgia [verchniy mel gruzii].– publishing house of the academy of science of the georgian ssr, tbilisi, 540 p. westermann, g.e.g. (2000): biochore classification and nomenclature in palaeobiogeography: an attempt at order.– palaeogeography, palaeoclimatology, palaeoecology, 158/1–2, 1–13. doi: 10.1016/s0031-0182(99)00162-5 ab stra ct this paper presents the first results of pollen analysis at the eponymous archaeological site of sopot. cultural layers have been examined for the presence of pollen grains and spores as well as the other palynomorphs. the palynological analysis of the cultural layer provides significant data on the presence of phytopathogens that had an influence on the neolithic agriculture. keywords: palynology, neolithic, sopot culture, croatia  first palynological results from the archaeological site of sopot, croatia  koraljka bakrač1, maja krznarić škrivanko2, slobodan miko1, nikolina ilijanić1 and ozren hasan1 1 croatian geological survey, sachsova 2, hr-10 000 zagreb 2 vinkovci municipal museum, archaeological department, trg bana josipa šokčevića 16, hr-32 100 vinkovci doi: 10.4154/gc.2015.23 1. introduction 1.1. general background the arrival of food-producing economies in the neolithic started the transformation of the natural landscape into the cultural landscapes we see today (lechterbeck et al., 2014). the study of past human activities and their environmental effect is high on the agenda of global change research. a record of pollen assemblages is one of the most common proxies employed for detecting the impact of human activities on the landscape. however, it is often difficult to detect and quantify human activities contained in palaeorecords due to their uncertainty and complexity. since the 1980s, with the publication of several influential monographs by dimbleby (1985), behre (1986) and birks et al. (1988), there has been increasing interest in the pollen records related to human activities. though pollen is universally considered one of the best tools for environmental reconstructions and high resolution climatic inferences (e.g. faegri & iversen, 1989; roberts et al., 2011, mercuri et al., 2012), the palynology of archaeological sites has peculiarities which could make plant landscape reconstructions difficult to obtain. human disturbance, poor pollen preservation and consequent low pollen concentrations are the most common reasons for the difficulties encountered when dealing with environmental reconstructions in archaeological contexts (dimbleby, 1985; horowitz, 1992). 1.2. location, physical environment and vegetation this paper presents the first results of research drilling for pollen analysis at the eponymous archaeological site of sopot. drilling was conducted in 2010 to provide an overview of the spatial relationship of the „tell” with the immediate surroundings and preliminary data on the geological and cultural layering of sopot. the archaeological site investigated in this study is located in eastern slavonia in the vicinity of vinkovci, croatia (fig.1). the sopot – 8 core (x=5013673,1; y= 6560667,1) contains three cultural layers, and the total length is 335 cm. sopot is located in the slavonian region in eastern croatia on the southern banks of the river bosut. the basement of the site are the sedimentary rocks of quaternary age, mainly loess and loess-like deposits (fig.1).climazonal vegegeologia croatica 68/3 303–311 2 figs. 2 pls. zagreb 2015 geologia croaticageologia croatica geologia croatica 68/3geologia croatica 304 geologia croatica 68/3geologia croatica 304 middle group at 4790 to 4360 cal. bc and the youngest objects from 4340 to 3940 cal. bc. a newly discovered starčevo culture layer forms the fourth group of dates being dated as 6060 to 5890 cal. bc. they are also the oldest non sopot culture dates from the site itself. in all of the horizons the houses were built on the same places with just a slight horizontal deviation. density in the spatial arrangement of buildings is increased towards thecentre of the settlement and it is obviously a planned structure of the settlement (krznarić škrivanko, 2015). the youngest horizon of houses was partially destroyed by the digging of ditches and smaller pits and holes, and the typological characteristics of the pottery found in them suggests that they belong to the eneolithicperiod (krznarić škrivanko & balen, 2006; krznarić škrivanko, 2011). between 1996 to 2006, excavations at sopot for archaeobotanical analysis revealed a comprehensive list of both domestic and wild plant species (krznarić škrivan ko & reed, 2008). 71% of the identified plant remains were domestic cereals, including triticum mono coc­ cum (emmer), triticum dicoccum (einkorn) and hordeum vulgare (barley). other crops present include pisum sativum (pea), lens sp. (lentil), and linum cf. usitatissimum (flax), (2% of the assemblage). also recovered were a number of fruit (10%) and weed species (17%) including a relatively large deposit of physalis alkekengi seeds in the floor of the house. both the domestic and wild species recovered indicate that a fully integrated agricultural system was practiced at sopot, supplemented by local wild resources. tation in the area of vukovar-srijem is composed of floodplain oak forests and mixed oak-hornbeam forests. it belongs to the european-planar vegetation belt of the eurosiberiannorthamerican region (trinajstić, 1998). today, forests cover about 28% of the area in the county, and most of the area (about 62%) is agricultural land suitable for intensive farming (arable land), and active rural and urban areas (službeni vjesnik – službeno glasilo vukovarsko-srijemske županije (2006). eastern croatia has a moderate continental climate characterized by sunny and hot summers and cold and snowy winters. the climate in vinkovci, which is warm and temperate, is according to köppen and geiger classified as cfb. there is significant rainfall throughout the year withaverage annual rainfall of 663,7 mm for the period 19712000. even the driest month (february) still has a lot of rainfall (36,9 mm). the average annual temperature in vinkovci is 11.2 °c. the warmest month of the year is july with an average temperature of 21.3 °c. the lowest average temperature is in january (0.4 °c). 1.3. archaeological and historical background sopot, the eponymous site of the sopot culture, is placed 3 kilometres to the southwest of vinkovci on the right bank of the river bosut (fig. 1). it is a tell type structure 113 by 98 metres and about 3 metres in height. dating of the sopot culture samples has so far provided three groups of dates (krznarić škrivanko, 2011). the oldest objects are dated at 5050 to 4550 cal. bc, the figure 1: location of sopot coring site: a) location of the study area within croatia; b) satellite image; c) geological map of the vinkovci area modified after the geological map of croatia m1:300.000 – croatian geological survey – department for geology, 2009). bakrač et al.: first palynological results from the archaeological site of sopot, croatia geologia croatica 305 plate i sample 49-60 cm: a) chomotriletes circulus (wolff, 1934) fensome et al., 1990, b) spirogyra type 1 van geel & van der hammen 1978, c) betula, sample 70-80 cm: d) cichoriaceae, e) nuphar, f ) zygnema; sample 80-90 cm: g) pinus, h) sphagnum, i) mougeotia; sample 100-110 cm: j) polypodium, k) chomotriletes circulus (wolff, 1934) fensome et al., 1990, l) poaceae; sample 120-130 cm: m) abies, n) cichoriaceae, o) elodea; sample 140-150 cm: p) tilletia, r) nymphaea, s) spirogyra type 3a van geel & van der hammen, 1978. geologia croatica 68/3geologia croatica 306 geologia croatica 68/3geologia croatica 306 plate ii sample 180-190 cm: a) cichoriaceae, b) dinocyst, c) pinus; sample 190-200 cm: d) tilletia, e) tilletia in fluorescence, f ) cichoriaceae; sample 260-270 cm: g) virgodiniumpelagicum (sütőné szentai, 1990) sütőné szentai, 2010, h) lingulodinium machaerophorum (deflandre & cookson, 1955) wall, 1967, i) polypodium. bakrač et al.: first palynological results from the archaeological site of sopot, croatia geologia croatica 307 2. methods 2.1. field-work sites were cored using a gasoline powered percussion hammer vibrokorer eijkel kamp cobra tt rd32 equipped with percussion gouges, used to take reasonably undisturbed samples from depths to about 7 metres, without the use of a drilling liquid (so samples were suitable for chemical analysis). samples were extracted from the piston corer in the field, wrapped in cling film, aluminium foil and plastic sheeting and stored in a cold store at 4°c. 2.2. pollen for the pollen analysis, a minimum 1 cm3 of the sediment was subsampled every 10 cm down the core using a metal volumetric subsampler. standard palynological processing techniques (faegri & iversen, 1989; moore et al., 1991) were used to extract the palynomorphs. the residues were stored and mounted in silicone oil. slides were counted using an olympus bh-2 transmitted light microscope at x400, x600 and x1000 (oil immersion), magnifications combined with the interference contrast. a fluorescence technique was used in order to distinguish reworked palynomorphs. whole slides were counted for palynomorphs. the pollen concentration was too low to count 300 pollen grains per sample (< 900 pollen grains per 1 g of sediment). photos were taken using a moticam 2300. identification of pollen grains was performed by comparison with the pollen reference collection of the department of botany and botanical garden, faculty of science, university of zagreb, and by consulting the pollen key: moore et al. (1991). palynological residues and slides are stored in the collection of the croatian geological survey. pollen diagram (fig. 2) was plotted using the software c2 version 1.5 (juggins, 2007). all terrestrial pollen and spores were included into the pollen calculation sum. 3. results after a review of material from eight wells (sopot-1 to sopot-8) drilled in the area of the archaeological site of sopot, borehole sopot-8 (as the deepest borehole containing cultural layers) was selected for palynological analysis. based on macroscopic observations 15 samples were tested for their palynology. generally, in all the analysed samples, there is relatively little organic residue with a high proportion of opaque or semi-opaque phytoclasts – black particles with or without any visible structure belonging to the inertinite maceral group (tyson, 1995) as well as resinite. most palynomorphs (spores and pollen grains, fresh-water algae) show a moderate intensity while dinocysts have a low intensity of fluorescence. pollen was found in all the samples but pollen preservation and the level of pollen identification wasn`t good. besides crumpled pollen, many grains had a slightly reworked exine. in almost all cases pollen is identifiable at the genus level, some at the family level, and plants which have only one species in a genus are identifiable up to the species level. unfortunately, pollen counts didn’t reach the predetermined total of 200 grains. these are still much too low for any reliable environmental interpretation. the results of pollen analysis at sopot-8 site are presented as a percentage pollen diagram (fig.2). the main characteristic is a low pollen concentration (from 35 to 871 pollen grains per 1 g of sediment) and a high percentage of degraded pollen. the main taxa are pinus, cichoriaceae and tilletia. in most samples there is a freshwater alga chomo­ triletes circulus (pl.1.a, k). according to a visual examination of the pollen diagram (fig. 2) it reveals at first sight, four zones corresponding to the cultural layers. the main characteristic of zone sop-1 is a high percentage of pinus (~40–80%), which increases towards the top of the zone, whereas tilletia and poaceae decrease towards the top of the zone which belong to the i. cultural layer. the main characteristic of zone sop-2 is a high percentage of cichoriaceae (~20–30%) and again tille­ figure 2: percentage pollen diagram. geologia croatica 68/3geologia croatica 308 geologia croatica 68/3geologia croatica 308 rated by the alteration of wood in an oxidising environment at normal or elevated temperatures. mechanical damage, especially of dinocysts, is the result of redeposition. moderate fluorescence intensity of lipid-rich palynomorphs confirms the weak oxidation of the organic component (tyson, 1995). phytoclasts mostly belong to the vascular tissue of gymnosperms, which together with a high proportion of the resin in the total organic residue suggest the existence of coniferous forests in the vicinity. gymnosperm pollen, unfortunately, has a small proportion partly due to post-degradation oxidation processes within subaerial conditions. exine thickness and the amount of sporopolenine is important (havinga, 1964, birks & birks, 1980, dimbleby, 1985). cichoriaceae pollen is well known for its resistance to corrosion, whereas some tree pollen types with thin exina can be very easily degraded. generally at the sopot site, a reduction in the proportion of conifers and an increase in herbaceous pollen could be observed. deforestation for agriculture and firewood could be the reason for the reduced forest content, and the increased proportion of pollen of herbaceous plants of the family cichoriaceae and especially teliospores of tilletia. the dominance of the genus tilletia teliospores is observed in all four cultural layers. mildew as parasites occur primarily on plants from the grass family (poaceae), and therefore represent one of the most dangerous pathogens on cultivated species from this family (wheat, barley, rye, oats, corn, etc.). bunt is a disease caused by the fungus tilletia tritici (syn. t. caries) and t. laevis (syn. t. foetida). the disease occurs primarily in wheat, although t. tritici and t. lae­ vis can attack barley and rye. the rusts and smuts of cereals have afflicted us since the first neolithic farmers planted cereals 10,000 years ago (money, 2007). „smelly“ or „hard“ blight is a disease known since the world’s first granary, from mesopotamia and egypt (about 4000 bc), where man began to consciously grow grain as the first crops (johnsson, 1990). there is also „written evidence“ from that time on the attempts of treating grain soaking in sea water. similar research was presented by mazurkiewicz-zapałowicz & okuniewska-nowaczyk (2015) for the medieval cultural layers from poland. in the youngest layer (zone sop-4) the proportion of tilletia spores is more than 60%. maybe disease was a possible cause of migration from the area for a while. in the meantime, the progressive succession occurs because of the lack of anthropogenic impacts on agricultural and grassland areas. it could gradually turn into broadleaved forest (corylus and betula as pioneer species appear). in europe, the replacement of woodland by farmland and pasture was marked by the decrease of tree pollen with the rise of cereal and cropland weeds pollen including plan­ tago, aster and graminae (birks et al,, 1988). a decline in tree pollen may be due to human activities, climatic change or both. the former would be manifested by the decline of selected tree pollen in different sites of the same region; the latter would usually cause a pollen decline for many types of trees on a large spatial scale. deforestation, hunter-gathtia, with a marked decrease in pinus towards the top of the zone. zone sop-3 is dominated by tilletia (~40– 65%) and aquatic plants. a very similar assemblage is from the last zone sop-4 where the previously dominant taxa tilletia increase even more to ~65%. only a few palynomorphs exist in the oldest zone sop-1 (290-230cm). there are teliospores of tilletia, though only a small number, unlike the later cultural layers. there are pine pollen (pinus), grass pollen from the family poaceae (perhaps a wild crop, but due to poor preservation of the grain cannot be more specific) and fern spores from the family polypodiaceae (pl.2.i). there are also relatively numerous dinocysts: lingulodinium (pl.2.h), virgodinium (pl.2.g) and spiniferites, largely mechanically damaged, from the miocene era. the second zone sop-2 (230-170cm) reveals the dominance of the cichoriaceae (pl.2.a,f) pollen. in this layer, the ratio of teliospores of the tilletia (pl.2.d-e) genus is increased, as well as those of the freshwater algae chomotri­ letes circulus. the proportion of resedimented dinocysts had decreased. at the base of the zone the most abundant pollen is pine (pinus) (pl.2.c), but its proportion reduces as the proportion of cichoriaceae pollen increases. fern spores are from the family polypodiaceae. in the third zone sop-3 (170-100cm) the proportion of cichoriaceae pollen (pl.1.n) decreases, while teliospores of the genus tilletia (pl.1.p) increases. freshwater algae (pl.1.s) increase, while dinocysts decrease in their relative proportions. there are also pollen of aquatic plants elodea (pl.1.o), nymphaea (pl.1.r) and spores of ferns from the family polypodiaceae. at the end of the zone, tilletia spores slightly decrease while at the same time grass pollen (pl.1.l) increases in proportion. in the youngest zone sop-4 (100-50cm) the proportion of cichoriaceae pollen (pl.1.d) is more or less the same around 10%, grass pollen decreases, while teliospores of the genus tilletia greatly increase. there is a significant proportion of freshwater algae: mougeotia (pl.1.i), zygnema (pl.1.f) and spirogyra (pl.1.b), while dinocysts completely disappear. there is also the pollen of aquatic plants and ferns from the family polypodiaceae. birch trees, betula (pl.1.c) and hazel, corylus slightly increase in the upper part of the zone. 4. discussion relatively little organic residue with a high proportion of the opaque or semi-opaque phytoclasts indicate an oxic environment in which other organic compounds are selectively destroyed. the absolute domination of structured phytoclasts of the total organic residue of all the analysed samples indicates the pronounced fluvial input of terrestrial organic components which often breaks down into smaller opaque particles during transport. inertinite with the fine preservation of the microstructure indicates its charcoal origin (ercegovac & kostić, 2006). inertinite is very abundant in stream and lacustrine deposits. it can be abundant or dominant (or common) in delta-front and prodelta, fresh water swamp, lagoon, lake and river sediments. inertinite is genebakrač et al.: first palynological results from the archaeological site of sopot, croatia geologia croatica 309 ering, cultivation and settlement were common human activities during prehistoric times. these activities led to a variety of landscapes with distinctive vegetation and hence different pollen assemblages. in temperate forests, li yiyin et al. (2008) distinguish five stages which can be observed: stage 1: a period of primeval vegetation growth; stage 2: deforestation for farming; stage 3: cultivation; stage 4: abandonment of the cultivated land; stage 5: restoration of primeval forest. this is not so easy to differentiate in sopot because of the poor pollen preservation and low concentration. it is supposed that only stage 3 (cultivation) and stage 4 (abandonment of the cultivated land) could be distinguished. all four cultural layers (zones) represents stage 3 (cultivation), while stage 4 (abandonment of the cultivated land) could possibly be recognized between the cultural layers. the occurrence of zygosporesof spirogyra, mougeotia, and zygnemain the quaternary deposits indicates a shallow eutrophic water body with warm pluvial periods which supplied fluvial sediments (medeanic, 2006, van geel et al., 1989, worobiec, 2014). in the zygnemataceae, zygospore formation occurs mostly in the spring in clean, oxygen rich, shallow fresh water (van geel, 1976). the optimal temperature for zygnema is 15–20°c, and for most species of spirogyra the optimum is 14–22°c (hoshaw, 1968). such high temperatures are easily reached in shallow water exposed to direct solar radiation, at least during the warm season (van geel, 1978). a ph value of 7.0–8.0 was inferred from the zygospores of spirogyra (grote, 1977). the strong presence of cichoriaceae pollen in the archaeological layers could be explained by two different interpretations (florenzano et al., 2015): a) selective corrosion of the less resistant exines (bottema, 1975; dim bleby, 1985) resulting in their overrepresentation in conservative and poor sediments, as in some layers from archaeological sites; b) the presence of pasturelands reflecting animal breeding and grazing areas (birks et al., 1988, behre, 1986, mercuri et al., 2010, florenzano et al., 2012) in which these pollen grains are abundant as they are linked to herbivore action and animal browsing leading to a certain selection of plants. in general, cichoriaceae well represent the xeric environments that developed as a result of continuous human pressure, especially in the mid and late holocene (mercuri et al., 2010, 2012). in the mediterranean and arid zones, and namely in archaeological sites, these pollen grains have been observed both in spectra with selective deterioration and in deposits influenced by human activities. the overrepresentation of cichoriaceae pollen in southern italy sites is properly linked to the presence and the practice of grazing (mercuri et al., 2010). the results of this study indicate that the landscape at sopot was dynamic, with significant changes of vegetation composition and hydrology. because of the low pollen concentration and poor preservation we can only make suppositions about the vegetation cover. initially, the study area around sopot was probably covered by conifer and deciduous trees and stagnant water (based on fresh-water algae). it turned into an herb-dominated environment during the cultural phases (pastures and cultivated fields). abandoned agricultural fields probably turned into bushy vegetation, oak and hornbeam forest and eventually beech forest. at the time of deposition of the studied sediments, controlled or uncontrolled burning (based on the charcoal particles in most samples) frequently occurred, together with intensive erosion of the surrounding sediments, which confirms that at the time the climate was humid and that there were cleared areas susceptible to erosion (confirmed by resedimented palynomorphs). it is assumed that the studied area was inhabited since the time of deposition of the sediments at depths of 2.60-2.95 m. previously determined c14 dates of the layers from archaeological material (krznarić škrivanko, 2011) could be correlated with the cultural layers from the sopot-8 core. according to this the oldest cultural layer from the zone sop-1 could be from the starčevo culture dated as 6060 to 5890 cal. bc,while the cultural layer from zone sop-2 could be from the oldest sopot culture dated as 5050 to 4550 cal. bc, cultural layer from zone sop-3 could be from 4790 to 4360 cal. bc and the cultural layer from zone sop-4 could be from 4340 to 3940 cal. bc. palynological research in slovenia suggests that human impact on the neolithic landscape was in the form of smallscale forest clearance, burning and coppicing, whereas major landscape-scale forest clearance occurred only after c. 3000 cal. bp (andrič & willis, 2003). however, it seems that anthropogenic impact in the neolithic period significantly altered the forest composition. differences between individual phytogeographic regions of slovenia became apparent after c. 8900 cal. bp and increasing palynological richness (biodiversity) after c.7000 cal. bp is presumably associated with the neolithic transition to farming (andrič & willis, 2003). the vegetation history at two small basins in slovenia, located in the bela krajina region, was investigated and compared using palaeoecological techniques (andrič, 2007). palynological research was undertaken in bosnia (wolters & bittmann, 2006) within the archaelogical excavation in the tell-settlement of okolište in the hilly mountains of central bosnia (hofmann et al., 2008). the local cultural group is termed the „butmir culture“ and dates to the late neolithic in terms of the local chronology. in calendar years this corresponds roughly to the period between 5200 and 4500 cal. bc. in cultural terms, central bosnia during the late neolithic is a kind of a hybrid of adriatic and carpathian influences, especially from the vinča-culture. 5. conclusion the results indicate that the landscape at sopot was dynamic. because of the low pollen concentration and poor preservation we can only make suppositions as to the type of vegetation cover. initially, the study area around sopot probably was covered by conifer and deciduous trees with stagnant water in the vicinity. it turned into an herb-dominated environment during the cultural phases (pastures and cultivated fields). abandoned agricultural fields probably turned into bushy vegetation, oak and hornbeam forest and eventually geologia croatica 68/3geologia croatica 310 geologia croatica 68/3geologia croatica 310 beech forest. at the time of deposition of the studied sediments controlled or uncontrolled burningfrequently occurred, as well as intensive erosion. according to previously determined c14 dates, the oldest cultural layer from the zone sop-1 could be from the starčevo culture dated as 6060 to 5890 cal. bc, while the cultural layer from zone sop-2 could be from the oldest sopot culture dated as 5050 to 4550 cal. bc. thecultural layer from zone sop-3 could be from 4790 to 4360 cal. bc and the cultural layer from zone sop-4 could be from 4340 to 3940 cal. bc. this research suggests that these sediments from the cultural layers are not suitable for detailed pollen analysis and further sampling should be carried out from more promising sediment in the surrounding area. detailed vegetation and environmental reconstructions must rely on multidisciplinary data. acknowledgement the authors wish to thank colleagues who participated in the field investigation and hrvoje vulić for improving the english. this research was supported by the projects of croatian ministry of science, education and sports no.181-19530680363 “holocene sediments as archives of environmental chan ge in the adriatic catchments”; no. 181-1811096-1093: “basic geological map of the republic of croatia 1:50 000”; “lost lake landscapes of the eastern adriatic shelf (loladria)” and “standardisation and applied investigation of quaternary sediments in croatia (sapiq)” supported by croatian science foundation. we are very grateful to maja andrič and anonymous reviewer for their valuable and helpful reviews. reference andrič, m. (2007): the holocene vegetation development in bela krajina (slovenia) and the impact of fist farmers on the landscape.– the holocene 17/6, 763–776. andrič, m. & willis, k.j. (2003): the phytogeographical regions of slovenia: a consequence of natural environmental variation or prehistoric human activity?– journal of ecology, 91, 807–821. behre k.e. (1986): anthropogenic indicators in pollen diagrams. a.a.balkema, rotterdam, 232 p. birks, h.j.b. & birks, h.h. (1980): quaternary palaeoecology. (reprinted 2004 by the blackburn press, new jersey) edward arnold, london. birks, h.h, birks, h.j.b., kaland, p.e. & moe, d. (eds) (1988): the cultural landscape past, present and future.– cambridge university press, cambridge, 521 p. bottema, s. (1975): the interpretation of pollen spectra from prehistoric settlements (with special attention to liguliflorae).– palaeohistoria, 17, 17–35. dimbleby, g.w. (1985): the palynology of archaeological sites. london: academic press, 176 p. ercegovac,m. & kostić, a. (2006): organic facies and palynofacies: nomenclature, classification and applicability for petroleum source rock evaluation.– int. j. coal. geol., 68, 70–78. faegri, k. & iversen, j. (1989): textbook of pollen analysis. (4th edition by faegri, k., kaland, p.e. & krzywinski, k.).− john wiley & sons new york, 328 p. florenzano, a., marignani, m., rosati, l., fascetti, s. & mercuri a, m. (2015): are cichorieae an indicator of open habitats and pastoralism in current and past vegetationstudies?– plant biosystems, 149/1, 154–165. doi:10.1080/11263504.2014.998311 florenzano, a., torri, p., rattighieri, e., massamba n’siala, i. & mercuri, a.m. (2012): cichorioideae-cichoriaceae as pastureland indicator in pollen spectra from southern italy.– in: atti del congressoa.i.ar. 2012 modena. modena, 22–24 febbraio, 2012, bologna: patron editore, 342–353, isbn/issn: 9788855531665 grote, m. (1977): über die auslösung der generativen fortpflanzung unter kontrollierten bedingungenbei der grünalge spirogyra majuscule.– z. pflanzenphysiol., 83, 95–107. havinga, a.j. (1964): investigation into the differential corrosion susceptibility of pollen and spores.– pollen et spores, 6, 621–635. hofmann, r., kujundžić-vejzagić, z., müller, j., rassmann, k. & müller-scheeßel, n. (2008): rekonstrukcija procesa naseljavana u kasnom neolitu na prostoru centralne bosne.– glasnik zemaljskog muzeja u sarajevu (nova serija), 50/51, 2008/2009, 11– 178. horowitz, a. (1992): palynology of arid lands. amsterdam.– elsevier, 546 p. hoshaw, r.w. (1968): biology of the filamentous conjugating algae. algae, man and the environment.– in: syracuse university press, syracuse. johnsson, l. (1990): survival of common bunt (tilletia caries (dc) tul.) in soil and manure.journal of plant diseases and protection, 97, 502–507. juggins, s. (2007): c2 version 1.5: software for ecological and palaeoecological data analysis and visualisation [program].– newcastle upon tyne: university of newcastle. krznarić škrivanko, m. (2011): radiokarbonski datumi uzoraka sa sopot, panonski prapovijesni osviti zbornik radova posvećenih korneliji minichreiteruz 65. obljetnicu života, institut za arheologiju, zagreb, 209–227. krznarić škrivanko, m. (2015): rezultati dimitrijevićevih istraživanja sopota u svjetlu novih istraživanja“.– opvscvla archaeologica, 36, zagreb (in press). krznarić škrivanko, m. & balen, j. (2006): osma, deveta i deseta sezona sustavnog istraživanja gradine sopot (godina 2003., 2004., 2005.), obavijesti hrvatskog arheološkog društva, xxxviii/1, 51–60. krznarić škrivanko, m. & reed, k. (2008): the late neolithic site of sopot, vinkovci: results of the site stratigraphy, c14 dates, and the analysis of archaeo-botanical and osteological remains.– the european archaeologist, issue no. 28, winter 2007/2008. lechterbeck, j., edinborough, k., kerig, t., fyfe, r., roberts, n. & shennan, s. (2014): is neolithic land use correlated with demography? an evaluation of pollenderived land cover and radiocarbon-inferred demographic change from central europe.– the holocene, 24/10, 1297–1307. li, yy., zhou, lp. & cui, ht. (2008): pollen indicators of human activity.– chinese sci bull., 53, 1281–1293. mazurkiewicz-zapałowicz, k. & okuniewska-nowaczyk, i. (2015): mycological and palynological studies of early medieval cultural layers from strongholds in pszczew and santok (western poland).– acta mycologica, 50/1. medeanic, s. (2006): freshwater algal palynomorph records from holocene deposits in the coastal plain of rio grande do sul, brazil.– rev. palaeobot. palynol., 141, 83–101. mercuri a, m., bandini mazzanti, m., torri, p., vigliotti, l., bosi, g., florenzano, a., olmi, l. & massamba n’siala, i. (2012): a marine/terrestrialintegration for mid-late holocene vegetation history and the development of the culturallandscape in the po valley as a result of human impact and climate change.– vegetation historyand archaeobotany, 21, 353–372. doi: 10.1007/s00334-012-0352-4 mercuri, a.m., florenzano, a., massamba n’siala, i., olmi, l., roubis, d. & sogliani, f. (2010): pollen from archaeological layers and cultural landscape reconstruction:case studies from the bradano valley (basilicata, southern italy).– plant biosystems, 144/4, 888–901. bakrač et al.: first palynological results from the archaeological site of sopot, croatia geologia croatica 311 money, n.p. (2007): the triumph of the fungi: a rotten history.– oxford university press, 197 p. doi: 10.1093/acprof:oso/9780195189711.001.0001 moore, p.d., webb, j.a. & collinson, m. (1991): pollen analysis (second edition).− blackwell sci. publication, london, 216 p. roberts, n., brayshaw, d., kuzucuoglu, c., perez, r. & sadori, l.(2011): the mid-holocene climatic transition in the mediterranean: causes and consequences.– the holocene, 21, 3–13. službeni vjesnik – službeno glasilo vukovarsko-srijemske županije, broj 18. god. xiv vinkovci, 27. prosinca 2006; http://www.vusz.hr/ cms_data/contents/vsz/folders/dokumenti/sluzbeni_ vjesnik/~contents/zmv2asw7n9czzu2f/2010-2-10-329363-vjesnik18-06.pdf trinajstić, i. (1998): fitogeografsko raščlanjenje klima zonalne šumske vegetacije hrvatske.– šumarski list hr. 9, 10, (xxii, 407–421). wolters, s. & bittmann, f. (2006): pollen analytische untersuchungenzur landschaftsentwicklungim visokobecken/bosnien-herzegowina.– bericht der römisch-germanischen kommission, 87, 167–174. tyson, r.v. (1995): sedimentary organic matter.– organic facies and palynofacies. chapman and hall, london, 615 p. van geel, b. (1976): fossil spores of zygnemataceae in ditches of a prehistoric settlement in hoogkarspel (the netherlands).– rev. palaeobot. palynol., 22, 337–344. van geel, b. (1978): a palaeoecological study of holocene peat bog sections in germany and the netherlands.– rev. palaeobot. palynol., 25, 1–120. worobiec, e. (2014): fossil zygospores of zygnemataceae and other microremains of freshwater algae from two miocene palaeosinkholes in the opole region, sw poland.– acta palaeobotanica, 54/1,113–157. doi: 10.2478/acpa-2014-0005 manuscript received june 11, 2015 revised manuscript accepted september 16, 2015 available online october 31, 2015 geo.cro.2-3-61-kb.pdf 113 � bernhard hubmann1, lisa verderber2 and fritz messner3 ab stra ct the lower to middle devonian (emsian – eifelian) calcareous green algal fl ora of the graz palaeozoic (austria) contains halimedalean representatives of pseudolitanaia, pseudopalaeoporella, zeapora, maslovina and a new lanciculoid taxon. occurrences within the graz thrust complex are restricted to four localities in the rannach nappe and may be characterised as monogeneric mass occurrences. consequently, they are interpreted as algal baffl estones originating from halimedalean meadows. keywor ds: devonian, green algae, mass occurrences, graz palaeozoic, austria 1 institute for earth sciences, karl-franzens-universität graz, heinrichstr. 26, a-8010 graz, austria; (bernhard.hubmann@uni-graz.at) 2 bg/brg carneri, carnerigasse 30-32, a-8010 graz, austria 3 auenbruggergasse 8, a-8073 feldkirchen bei graz, austria devonian calcareous green algal fl ora of the rannach nappe (graz palaeozoic, austria) geologia croatica 61/2–3 113–122 5 figs. 2 pls. zagreb 2008 geologia croaticageologia croatica � 1. introduction 1.1. the palaeozoic of graz weakly and/or unmetamorphosed palaeozoic successions are irregularly distributed in austria (fig. 1). generally two major regions of palaeozoic developments can be distinguished which are separated by the periadriatic fault, the most prominent alpine fault system. these are the eastern alpine variscan sequences; (i.e. the greywacke zone, the gurktal nappe, the graz palaeozoic and some isolated outcrops in south styria and burgenland) and the southern alpine sequences (i.e. the carnic alps and the karawanken mountains). the palaeozoic graz region extends over about 1250 km2 and is isolated from other low grade metamorphic (anchizonal to greenschist) facies, palaeozoic occurrences by tectonic bo undaries in the north, east and west as well as by younger overlying strata in the south (fig. 2). the northwestern and western parts of the graz palaeozoic are bordered by polycrystalline units (austroalpine crystalline zone), i.e. the gleinalm, st. radegund and the raabalm. further south, palaeozoic successions are transgressively overlain by neogene sediments of the “styrian basin” whereas the southwestern part is unconformly overlain by upper cre taceous sediments of the kainach gosau (cf. fig. 2). facies developments are characteristic of the palaeozoic graz as well as “polyfacial” nappes but the original relationships of these to each other have not been clearly identifi ed. investigations based on lithology, tectonic position and metamorphic superimposition divide the graz palaeozoic into bas al, intermediate and upper nappe groups (fritz & neubauer, 1990). these three nappe systems are identifi ed by specifi c characteristics and contain the following units:fi gu re 1: austria and its disconnected palaeozoic units (shaded areas). geologia croatica geologia croatica 61/2–3 114 the basal nappe system (upper silurian to middle de vonian) consists of the “schöckl-hochschlag-nappe-group” and was deformed under upper greenschist facies conditions (hubmann et al., 2006). volcanoclastics dominate the late silurian to early devonian, while in the middle devonian time span carbonates prevail. the intermediate nappe system (early silurian to upper devonian) consists of the “laufnitzdorf-nappes” and “kalkschiefer nappes” and contains pelagic limestones, shales, vol canoclastics as well as siliciclastics. the upper nappe system (upper silurian to upper car boniferous) consists of the “rannach-hochlantsch-nappes”. both nappes have similar facies development in common, es pecially from the emsian to the givetian. successions of the rannach nappe are characterised by volcanoclastic rocks (early to middle devonian; reinerspitz group), siliciclastics and fossil-rich carbonates (early to middle devonian; ran nach group, lantsch group) of near-shore environment fol lowed by the pelagic forstkogel group (late givetian to bashkirian) and the shallow marine dult group (hubmann et al., 2003). palaeogeographic interpretations of the whole palaeozoic succession have resulted in the assumption that the rannach and hochlantsch nappes represent nearshore facies developments, whereas the “laufnitzdorf facies” represents the area furthest away from the shore. successions of the schöckl nap pe have an intermediate position in this scenario (hub mann, 1993). the stratigraphic sequence indicates a sedimentary area changing from a passive continental margin with continental breakup (alkaline volcanism) to shelf and platform geometries during silurian to devonian time (fritz et al., 1992). during this time, constant subsidence resulted in in creasing carbonate production in the upper nappe system and during pragian to givetian time deposition changed from near-shore facies to open platform environments. when the carbonate platform drowned in the frasnian, cephalopod limestones were deposited. 1.2. review of stratigraphy and environmental architecture of the rannach nappe the main reasons why the rannach nappe offers the highest probability for algal discoveries are that it has the least metamorphic overprint, and the sedimentary successions were de veloped nearest to the shore in moderate water depths. due to basal volcanoclastics (kehr and kötschberg for mations) and marly crinoid-rich sequences (parmasegg formation), the peritidal flösserkogel formation is assumed to range from the lower pragian. the formation comprises different types of dolostones, siltto sandstones and subordinate dolomitic limestones which are interpreted as deposition in a supra to shallow subtidal, barrier-surrounded lagoon, or tidal fl ats (fenninger & holzer, 1978). near graz, the lower parts of the succession are interpreted as sand bars whereas the upper parts (which are separated by volcanic tuffs), contain meadows of the spaghetti-like stromatoporoid amphipora. the presence of very rare conodonts indicates a (lower?) emsian age (cf. ebner et al., 2000, 2001). another formation belonging to the rannach group is the plabutsch formation. it overlies or rather interfi ngers with the flösserkogel formation and predominantly contains typical “reefbuilding organisms” (hubmann, 1993, 2003) which are present in all sections. nevertheless, there is no outcrop evidence of a “true reef” rather than coral-stromatoporoidcarpets and lagoonal sediments which are the dominant fea tures. environmental investigations indicate deposition on a differentiated and slightly inclined carbonate platform (hub mann, 1993). the following features support the assumption that sedimentary conditions were unfavourable for reef formation: the rarity of in situ organisms, the intermittent but generous supply of clayey sediments (marl-limestone intercalations) and plentiful supply of lime mud, a temporary infl ux of large amounts of continental phytoclasts, storm impacts (several tempestite sequences within the profi les) and especially their effects on biocoenosis (hubmann, 1995). this phase is terminated by a repetition of tidal fl at deposits similar to the flösserkogel formation and obviously caused by a eustatic sea level fall. a transgression resulted in a se quence with sharp biofacies contrasts between patch-reefs and monotonous mudstones of givetian age (the kollerkogel, tyrnaueralm, and zachenspitz formations). during the uppermost givetian to lower frasnian, sedimentation of shallow platform carbonates was replaced by micritic cephalopod limestones (steinberg formation). this sedimentation continued up to the bashkirian (sanzenkogel formation, forstkogel group). the sequence is terminated by shallow marine sediments, shales and limestones with birdseye structures. 1.3. algal horizons in two of the above mentioned formations, remains of algal thalli have been found, namely in the lower devonian (pra fi gu re 2: simplifi ed sketch of the graz palaeozoic. shaded patches correspond with areas of the rannach nappe outcrops. numbers of localities indicate the algal disocveries mentioned in the text. geologia croatica 115 bernhard hubmann et al.: devonian calcareous green algal fl ora of the rannach nappe (graz palaeozoic, austria) gian?-emsian) flösserkogel formation and in the middle de vo nian (eifelian) plabutsch formation. all these algal fi ndings are monogeneric mass occurrences and therefore make up the majority of the rock. consequently, they are interpreted as (par) autochthonous baffl estones. according to fenninger & holzer (1978), profi les of the flösserkogel formation contain “dasyclads” in the skeletal grains of the tidal fl at-deposits (pfaffenkogel). although further investigations confi rm the occurrence of reworked ortonella-remains and pieces of halimedaleans, algal thalli suitable for taxonomic determination have not been discovered. well preserved, determinable algae have so far been detected only at the following four localities: 2. sampling locations locality 1: (coordinates: 47°08’25’’n/15°15’27’’e) at a suc cession north of the rein monastery (ca. 20 km north of graz) an occurrence of little disarticulated lanciculoid algae was observed. this location is characterised by dark-grey to black, micritic to pelmicritic dolomites, (equivalent to amphipora meadows), and can be assigned to a slightly subtidal depositional environment. rocks yield a high number of algal thalli, mainly consisting of 8–15 articuli. moreover, the thalli at the surface of weathered rocks seem to be very well preserved. anatomic details, however, are only visible using a darkfi eld condensator. locality 2: (coordinates: 47°03’40’’n/15°22’34’’e) the oldest known algal taxon of the graz palaeozoic, zeapora, oc curs in the plabutsch formation (formerly “barrandeikalk”). it is restricted to one single outcrop, the former illite mine on the southern slope of the kollerkogel at the border to the urban area of graz. the black, graphitic horizon containing algal thalli is located only a few dm above the illite at the base of the plabutsch formation. penecke (1894) described these fragile fossils as zeapora gracilis, but assigned them mistakenly to the bryozoans. flügel (1959) recognized their algal nature and hub mann (2000) later revised and emended his description. locality 3: (coordinates: 47°05’25’’n/15°22’11’’e) the occurrence of pseudopalaeoporella lummatonensis and pseudolitanaia graecensis is also located near the city of graz (at a small path on the southern slope of the frauenkogel). the upper parts of the plabutsch formation are characterised by alternating layers of clayey limestones, red mudstones and marls. in the clayey limestones of this alternating sequence, masses of pseudopalaeoporella lummatonensis but only a subordinate number of pseudolitanaia graecensis thalli occur. fi gu re 3: stratigraphic column of the rannach nappe: 1) kehr formation, kötschberg formation; 2) parmasegg formation; 3) flösserkogel formation, bameder formation; 4) plabutsch formation; 5) kollerkogel formation; 6) steinberg formation; 7) sanzenkogel formation; 8) höchkogel formation; 9) hahngraben formation. geologia croatica geologia croatica 61/2–3 116 plate i 1 polished surface of algal limestone from locality 3 with an oblique section through pseudolitanaia graecensis. 2 thin-section of pseudolitanaia graecensis, transverse section exhibiting dichotomous off sets of cortical fi laments that branch off coarse medullary fi laments. locality 3. 3 cross-section of pseudolitanaia graecensis from the locality3. 4 weathered surface of algal limestone of locality 3 built up exclusively by densely packed thalli of pseudopalaeoporella lummatonensis. note the minor degree of calcifi cation in the medullary region of algal bodies. 5 oblique longitudinal section of pseudopalaeoporella lummatonensis showing a well defi ned cortical zone and a poorly calcifi ed central axis from the locality 3. 6 cross-section of pseudopalaeoporella lummatonensis from the locality 3. 7 surface of algal limestone from locality 2 (abandoned quarry at kollerkogel) with densly packed thalli of zeapora gracilis. 8 photomicrograph of thin-section illuminated by darkfi eld condensor. oblique longitudinal section of zeapora gracilis. note the large peripheral tubules fi lled with coarse-grained sparite. 9 photomicrograph of thin-section illuminated by darkfi eld condensor. cross-section of zeapora gracilis. cortical fi laments vary due to diff erent orientation of their clubbed shapes. all white scale bars represent 1 mm. geologia croatica 117 bernhard hubmann et al.: devonian calcareous green algal fl ora of the rannach nappe (graz palaeozoic, austria) geologia croatica geologia croatica 61/2–3 118 plate ii 1 weathered surface of an algal bearing limestone of locality 4 (road cut st. pankrazen) exhibiting cross sections of maslovina sp. 2 longitudinal section of a fragment of maslovina sp. note arrangement of numerous, fi ne medullary fi laments. 3 cross-section of maslovina sp. showing a well-defi ned medullar zone. note terminations of the cortical fi laments (amphora-shaped utricles). 4 weathered surface of the undetermined lanciculoid alga of locality 1. 5 photomicrograph of thin-section illuminated by darkfi eld condensator. longitudinal section the lanciculoid alga. 6 photomicrograph of thin-section illuminated by darkfi eld condensator. cross section is exhibiting four coarse medullary fi laments. 7−9 branching thalli of (7) pseudolitanaia graecensis, (8) zeapora gracilis, and (9) new lanciculoid alga. all white scale bars represent 1 mm. geologia croatica 119 bernhard hubmann et al.: devonian calcareous green algal fl ora of the rannach nappe (graz palaeozoic, austria) geologia croatica geologia croatica 61/2–3 120 the slight disarticulation of the thalli as well as their occurrence in clayey limestones, indicate a hydrodynamically low depositional environment. locality 4: (coordinates: 47°08’01’’n/15°11’02’’e) the outcrop is situated along the road about 2 km south of st. pankrazen (30 km nw of graz). the lower parts of the plabutsch formation contain a mass occurrence of maslovina which has recently been the subject of taxonomic investigation (ver derber, 2007). the respective horizon lays only a few dm above the basis of the shale horizon which corresponds in position to the illite horizon of the kollerkogel. 3. results and discussion the graz taxa genus pseudolitanaia mamet & préat, 1994 pseudolitanaia graecensis (hubmann, 1990) (fig. 4 b, fig. 5 b; pl. i, figs. 1–3; pl. ii, fig. 7) 1990 litanaia graecensis – hubmann, p. 148–150, fi gs. 3–4, pl. 35, fi gs. 1–6 1994 “litanaia” graecensis – herrmann & hubmann, p. 200, pl. 1, fi g. 5 1994 pseudolitanaia graecensis – mamet & préat, p. 148 the thallus is erect, cylindrical and continuous; its central part consists of 4 to 12, generally 8 irregular fi laments with appendices which develop towards a high number of cortical fi laments. these cortical fi laments are more or less oblique with a signifi cantly increasing diameter and a spatula-shape. they end up as fi ne fi laments of second order dichotomy and their termination resembles pseudopalaeoporella. average diameter of thalli is 2.8 mm, central fi laments vary between 0.25 and 0.33 mm, and cortical fi laments are approximately 0.88 mm thick. genus pseudopalaeoporella mamet & préat, 1985 pseudopalaeoporella lummatonensis (elliott, 1961) (fig. 4 a, fig. 5 a; pl. i, figs. 4–6) 1961 palaeoporella lummatonensis – elliott, p. 251–254, pl. 9, fi gs. 1–5; pl. 10, fi gs. 1–4 1983 palaeoporella lummatonensis – bassoullet et al., p. 553–554, pl. 13, fi gs. 1–2 1985 palaeoporella lummatonensis – roux, p. 564 1985 pseudopalaeoporella lummatonensis – mamet & préat, p. 70–72, pl. 3, fi gs. 2–8 1987 pseudopalaeoporella lummatonensis – mamet & pré at, p. 441, fi g. 4 fi gu re 4: green algae of the graz palaeozoic: reconstructions of the outer morphology of (a) pseudolitanaia graecensis, (b) pseudopalaeoporella lummatonensis, (c) zeapora gracilis, (d) maslovina sp. and (e) the undetermined lanciculoid alga. fi gu re 5: organisational diff erences of (a) pseudolitanaia graecensis, (b) pseudopalaeoporella lummatonensis, (c) zeapora gracilis, (d) maslovina sp. and (e) the undetermined lanciculoid alga. geologia croatica 121 bernhard hubmann et al.: devonian calcareous green algal fl ora of the rannach nappe (graz palaeozoic, austria) 1987 funiculus venosus n. gen. et n. sp. – shuysky & shirshova, p. 100–101, fi gs. 1–4 1990 pseudopalaeoporella lummatonensis – hubmann, p. 150–151, fi g. 5, pl. 35, fi gs. 1–6 1992 pseudopalaeoporella sp. – buggisch & flügel, p. 80, pl. 1, fi gs. 5–6; pl. 3, fi g. 2 1992 pseudopalaeoporella lummatonensis – mamet & préat, p. 55, pl. 3, fi gs. 1–11 1993 pseudopalaeoporella lummatonensis – hubmann & fenninger, p. 648–649, fi g. 1 1993 palaeoporella lummatonensis – vachard, p. 97–98, pl. 6, fi gs. 6, 18, 21–25 1994 pseudopalaeoporella lummatonensis – herrmann & hubmann, p. 198–200, fi g. 4, pl. 1, fi gs. 2–4 1994 pseudopalaeoporella lummatonensis – koch-fr üchtl & gee, p. 4–7, fi g. 3, pl. 1, fi gs. 1–6; pl. 2, fi gs. 7–15; pl. 3, fi gs. 16–23 when unbranched, thalli are cylindrical in form with a medullar zone and an extensive radial envelope. their diameters vary between 0.8–1.8 mm (mean value about 1.4). the medullar zone (~ 0.65 mm in diameter) is composed of several central tubes (up to 20?) and makes up approximately half the entire thallus diameter in cross section. central fi laments are arranged parallel to the thallus axis and are closely spaced. cortical fi laments develop from central tubes in acute angles into numerous lateral tubes with a second and third order dichotomy. the fi laments are commonly swollen just below the points of br anching and widen trumpet-like towards the thallus surface. genus zeapora penecke, 1894 zeapora gracilis (penecke, 1894) (fig. 4 c, fig. 5 c; pl. i, figs. 7–9, pl. ii, fig. 8) 1894 zeapora gracilis – penecke, p. 610, pl. 10, fi g. 11 1959 zeapora gracilis – flügel, p. 147–149, fi gs. 1–2 2000 zeapora gracilis – hubmann, p. 31–37, fi gs. 3–5 the thalli clearly show numerous peripheral tubules arranged around a central axis fi lled with a bundle of medullar fi laments. the medullar zone, usually 0.39 to 0.40 mm in diameter, consists of 4–6 (up to 10 and more) slightly interwoven fi laments. their diameters vary between 0.08–0.21 mm. the cortical zone is fi lled with massive carbonate deposits and perforated by roundly-elongated, densely packed fi laments. cortical fi laments vary considerably in longitudinal and cross sections due to different orientation of their bowl-like shapes. in some specimens, they seem to be segmented. genus maslovina obrhel, 1968 maslovina sp. the thallus is of a straight, cylindrical shape, occasionally un dulated. thalli vary in length between 3.0–11.5 mm, diameters measure between 0.78–2.55 mm (median value 1.9 mm), and are internally organised into a generally poorly calcifi ed medullar area and a cortical zone. the medullar part (diameter averages 0.93 mm) consists of a high number (>40) of interwoven fi laments (on average 0.04 mm wide) which give rise to fi ner, cortical fi laments (approximately 0.02 mm in diameter). they divide dichotomously at an acute angle and reach a third order dichotomy at the outermost cortical part. at this stage cortical fi laments develop towards densely packed am phora-shaped utricles which constitute the thallus surface. reproductive organs are not observed. maslovina sp. differs from the type species m. meyenii in having more numerous medullar tubes (> 40); these numerous tubes are also a characteristic feature of the devonian spe -cies m. australense (see mamet & pohler, 2002). the far greater thallus diameter and length is what distinguishes maslovina sp. from the two other species. the most remarkable differentiating feature, however, is that maslovina sp. has outermost cortical fi laments developing into a layer of tightly packed utricles which are, in contrast to m. meyenii, amphorashaped. m. australense differs from the other two species in showing irregularly spaced, thin terminal fi laments forming an irregular epiderm (mamet & pohler, 2002; obrehl, 1968). undetermined lanciculoid alga (fig. 4 e, fig. 5 e; pl. ii, figs. 4–6, 9) regularly segmented algal bodies only minor disarticulation exhibiting. thalli consist of up to 25 bowl-shaped elements (articuli, chalices) surrounding a straight or slightly bent stem (rachis). occasionally thallus ramifi cations are observed. thin-sections expose an internal assembly of four central fi laments pervading the whole thallus. they apparently do not vary considerably in diameter (approximately 0.15–0.20 mm), but may be slightly curved or undulating. from medullary fi laments a great number of cortical fi laments branch off radially, and perpendicular to the central axis decreasing their angles with growth. each tapered segment contains two rows of cortical fi laments and increases its diameter towards the growth direction. these segments resemble the bell of a trumpet and are densely stacked one above the other. the outer morphology of the articuli of our lanciculoid alga resembles the genus quasilancicula, but its chalices are more compressed. its tentacle-shaped chalice edges, however, show similarities with lepidolancicula. acknowledgement we acknowledge the valuable contributions made by the referees bernard mamet and felix schlagintweit. the study is a contribution to the project nap0001 (igcp 497). references bassoullet, j.p., berbier, p., deloffre, r., genot, p., poncet, j. & roux, a. (1983): les algues udoteaces du paléozoique au cénozoique. – bull. centres rech. explor. – prod. elf aquitaine, 7, 449–621. buggisch, w. & flügel, e. (1992): mittelbis oberdevonische karbonate auf blatt weilburg (rheinisches schiefergebirge) und in randgebieten: initialstadien der riffentwicklung auf vulkanschwellen. – geol. jb. hessen, 120, 77–97. ebner, f., hubmann, b. & weber, l. (2000): die rannachund schöckel-decke des grazer paläozoikums. – mitt. ges. geol. bergbaustud. österr., 44, 1–44. geologia croatica geologia croatica 61/2–3 122 ebner, f., fritz, h. & hubmann, b. (2001): das grazer paläozoikum: ein überblick. –in: hubmann, b. (ed.): paläozoikumsforschung in österreich. ber. inst. geol. paläont., k.-f.-univ. graz, 3, 34–58. elliott, g. f. (1961): a new british devonian alga, palaeoporella lummatonensis and the brachiopod evidence of the age of the lummaton shell-bed. – proc. geol. ass. london, 72/2, 251–259. fenninger, a. & holzer, h.-l. (1978): die genese der dolomitsandstein-folge des grazer paläozoikums. – mitt. österr. geol. ges., 69/1976, 109–162. flügel, h.w. (1959): zeapora penecke 1894: eine dasycladaceengattung aus dem mittel-devon von graz. – n. jb. geol. paläont., mh. 1959, 145–152. fritz, h. & neubauer, f. (1990): grazer paläozoikum. – exk.führer, tsk iii, 3. symp. tektonik, strukturgeol. kristallingeol., graz 24 p. fritz, h., neubauer, f. & ratschbacher, l. (1992): compression versus extension in the paleozoic of graz (eastern alps, austria). – zentralbl. geol. paläont., part i, 1991, 55–68. herrmann, r. & hubmann, b. (1994): devonian udoteacean green algae from the cantabrian mountains (santa lucía formation), nw-spain. – rev. espańola paleont., 9, 195–202. hubmann, b. (1990): udoteaceen (grünalgen) aus dem grazer paläozoikum/österreich (barrandeikalke, eifelium). – facies, 22, 147–158. hubmann, b. (1993): ablagerungsraum, mikrofazies und paläoökologie der barrandeikalk-formation (eifelium) des grazer paläozoikums. – jahrb. geol. bundesanst., 136/2, 393–461. hubmann, b. (1995): middle devonian shallow marine deposits of the graz paleozoic: fact and fi ction for deposition under ecological stress. – beitr. paläont., 20, 107–112. hubmann, b. (2000): zeapora penecke 1894 redefi ned: a halimedacean alga. – mitt. österr. geol. ges., 91, 31–37, 5 fi gs. hubmann, b. (2003): plabutsch-formation: nomen novum pro barrandeikalk (mitteldevon, grazer paläozoikum). – in: piller, w.e.(ed.): stratigraphia austriaca. österr. akad. wiss., schriftenr. erdwiss. komm., 16, 269–292. hubmann, b. & fenninger, a. (1993): pseudopalaeoporella lumma tonensis (elliott, 1961) aus dem mitteldevon der zentralen karnischen alpen. – carinthia ii, 183/103, 647–649. hubmann, b., pohler, s., schönlaub, h.-p. & messner, f. (2003): paleozoic coral-sponge bearing successions in austria. – ber. geol. b.-a., 61, 1–91. hubmann, b., suttner, t.j. & messner, f. (2006): geologic frame of palaeozoic reefs in austria with special emphasis on devonian reef-architecture of the graz palaeozoic. – joannea – geologie und paläontologie, 8, 47–72. koch-früchtl, u. & gee, c.t. (1994): middle devonian pseudopalaeoporella lummatonensis from the rhenish schiefergebirge (sauerland and eifel), western germany. – palaeontogr., 232, 1–13. mamet, b. & pohler, s.m.l. (2002): algae from early to middle devonian limestones, tamworth belt, n.s.w., australia. – alcheringa, 26, 435–450. mamet, b. & préat, a. (1985): sur quelques algues vertes nouvelles du givétien de la belgique. – rev. micropaléont., 28, 67–74. mamet, b. & préat, a. (1987): algues givetiennes du bord sud du basin de dinant et des regions limitrophes. – ann. soc. géol. belgique, 109, 431–454. mamet, b. & préat, a. (1992): algues du dévonian moyen de wellin (synclinorium de dinant, belgique). – rev. micropaléont., 35, 53–75. mamet, b. & préat, a. (1994): algues calcaires de l’eifélien inférieur. – rev. micropaléont., 37, 135–159. obrhel, j. (1968): maslovina meyenii – neue codiacea aus dem silur böhmens. – vestnik ústředniho ústavu geologického, 43, 367–370, praha. penecke, k.a. (1894): das grazer devon. – jahrb. geol. reichsanst., 43, 567–616. roux, a. (1985): introduction à l’étude des algues fossils paléozoiques (de la bactéric à la tectonique des plagues). – bull. centre rech. explor. – prod. elf aquitaine, 9, 465–699. shuysky, p. & shirshova, d.i. (1987): materialy k sistematike sifonvych vodoroslej (siphonales) [material and systematics of siphonous algae – in russian]. – akad. nauk sssr, sibirskoe otdelenie, trudy inst. geol. geofi z., 674, 86–109, novosibirsk. vachard, d. (1993): algues, pseudo-algues et microfacies carbonates du devonien du domaine ligerien (massif armoricain, france). – palaeontogr., 229, 53–113. verderber, l. (2007): devonian halimedacean green algae with special emphasis on a new species from the graz palaeozoic. – unpublished diploma thesis, k.-f. – university graz, 94 p. manuscript received february 19, 2008 revised manuscript accepted may 19, 2008 2022 | 75/1 | 177–188 | 8 figs. | 5 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction water and soil may be polluted with potentially toxic metals (ptms) as a result of human activities, such as metal mining and smelting, industrial and energy production, land application, waste disposal practices, or by accident. accumulated ptms in soils can be transported through the soil into the groundwater, thus causing deterioration of quality of groundwater used for human consumption. in this study, four soil profiles located in the area of the zagreb aquifer system (croatia) were sampled and analyzed. according to nakić et al. (2013), ptms, nitrates, pesticides, pharmaceuticals and chlorinated aliphatics are the main contaminants of groundwater within the zagreb aquifer system. in this study, we assessed the extent of retention of three ptms by soils having a wide range of properties such as cation exchange capacity (cec), organic matter (om), soil texture, ph, electrical conductivity (ec) and carbonate content. the ptms selected were cd, cu, and zn. cadmium (cd) is one of the most toxic elements with carcinogenic and teratogenic impacts (lichner et al., 2006). anthropogenic activities such as mining, p-fertilizers, and atmospheric deposition are conventional sources of soil cd pollution (smolders & mertens, 2013). because of its toxicity and relatively high mobility in soil, the behaviour and transport of cd are more widely studied compared to other heavy metals. most studies are concerned with the fate and transport of cd in soils under defined laboratory conditions (seuntjens et al., 2001). however, more recently, cd sorption and transport have been addressed under natural field conditions (elbana et al., 2018). according to their results, cd adsorption isotherms illustrate the weak or moderate sorption of cd in the analyzed soils. sorption of cadmium, zinc and copper in dominant soils of the zagreb aquifer system, croatia zoran kovač1, stanko ružičić1,*, vedran rubinić2, zoran nakić1 and marcel sertić1 1 university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, 10000 zagreb, croatia; (*corresponding author: stanko.ruzicic@rgn.unizg.hr) 2 university of zagreb, faculty of agronomy, svetošimunska cesta 25, 10000 zagreb, croatia doi: 10.4154/gc.2022.05 abstract contamination of soils with potentially toxic metals (ptms) is an environmental problem. in this study, sorption of cadmium (cd), zinc (zn) and copper (cu) in four soil profiles (two fluvisols, one gleysol, and one cambisol), representing the dominant soils of the zagreb aquifer system, were studied using a multi element laboratory batch test. mathematical expressions were applied to establish the relationship between the concentration of the adsorbent in the liquid phase and the solid phase at equilibrium and in laboratory conditions. the study revealed that the investigated soils have a higher capacity to sorb cu than zn and cd. the most significant physicochemical characteristics of soils, influencing sorption, are ph, carbonate content (minerals) and organic matter. although all ptms in all analyzed soils had a similar sorption capacity, the variation of sorption was higher in the siltic soils (fluvisols) compared with the texturally finer (loamic) gleysol and cambisol soils, as well as in the subsoil horizons compared with the topsoils. results indicate that sorption of ptms is more influenced by physicochemical characteristics at different soil depths than by soil type, which is confirmed with a higher affinity for zn and cd bonding in the topsoil horizons. also, it has been shown that cd may pose more of a threat to soils and groundwater due to its toxicity and relatively high mobility in comparison with zn and cu. zinc (zn) is an essential nutrient which can be toxic in large amounts (nan et al., 2002). several heavy metals such as zn, mo and cu are essential micronutrients required in the growth of both plants and animals. micronutrients are often applied in the form of fertilizers or as supplements in animal feed (elbana et al., 2018). therefore, the amount of zn added to the soils in agricultural practices is substantial (bonten et al., 2008). sorption of zn in soils is widely studied using laboratory conditions. dişli (2010) studied batch and column sorption of cu, zn, and mn in alluvial sediments and soils. according to his investigations, cu is the most strongly sorbed metal by alluvial soils. hough (2010) considered that copper (cu) is an essential micronutrient for human life and health, as well as for plants. copper compounds are widely used as fungicidal and bactericidal sprays, fertilizers, and stimulants of animal growth ( pietrzak & mcphail, 2004). prolonged use of cu-based chemi cals often results in soil contamination (pietrzak & mcphail, 2004; besnard et al., 2001). trakal et al. (2012) studied copper sorption on soil materials using batch laboratory experiment. they found that cu sorption is predominantly controlled by om content. potentially toxic metals form the important group of substances causing contamination of soil and groundwater. these elements may become toxic to plants and animals if their concentrations exceed certain values (adriano, 2001). contamination with ptms in soil may be geogenic or anthropogenic origin. geogenic sources of ptms (e.g. cd, cr, pb and zn) include parent rock, volcanic eruptions, deposition by wind or water, while anthropogenic sources include fertilizers, pesticides, sewage waste water, traffic, landfills, metallurgy, mining, etc. (ruley et al., article history: manuscript received april 20, 2021 revised manuscript accepted october 06, 2021 available online january 31, 2022 keywords: sorption, ptms, soil contamination, fluvisols, gleysols, cambisols, zagreb aquifer system g eo lo gi a c ro at ic a geologia croatica 75/1178 2006). potential sources of contamination in the studied soil profiles are industrial plants, traffic, airport and agriculture. soil can immobilize and thereby reduce the migration of ptms in its deeper parts, depending on the soil and the contaminants characteristics. the study of sorption properties of the soil is important because it can help to better understand processes of ptm transport through soil and consequently groundwater. adsorption processes are often influenced by various soil parameters, which are difficult to measure. the two empirical models most frequently used to describe ptm adsorption in/or on soil components are the freundlich and langmuir isotherms. these simple models are often used to express laboratory sorption data if specific models are lacking. adsorption of cu, cd and zn onto various soils and sediments was modelled by researchers using the freundlich and langmuir isotherms (jalali & moharrami, 2007; vega et al., 2001; sipos, 2009; elbana & selim, 2019; he et al., 2020). sipos (2009) studied sorption of cu and zn on a silty loam type of soil. the authors concluded that affinities of metals towards the soil samples from different horizons followed the same sequence, i.e. pb ≥ cu > zn. vega et al. (2008) studied the sorption of cu, pb and cd, from single and multi-element solutions. they concluded that sorption of cu is higher than cd sorption. cu and zn are often regarded as strongly sorbed metals by soils in comparison to cd. the sorption of cu and zn is correlated significantly with soil ph, om, cation exchange capacity (cec), amorphous oxides, and clay content (adriano, 2001; shaheen et al., 2009). also, soil ph can have the greatest effect of any single parameter on the mobility or retention of metals, with a greater retention and lower solubility of metal cations that occur at high soil ph (martinez & motto, 2000). appel & ma (2002) suggested that cd sorption was ph-dependent and could involve electrostatic surface reactions and/or innersphere complexation. numerous studies of contamination of soils and sediments with ptms have been carried out in the area of the zagreb aquifer system (durn et al., 1999; romić & romić, 2003; sollito et al., 2010). according to durn et al. (1999), high contents of pb, hg, and zn in the topsoils of the northern lowland residential parts of zagreb have been attributed only to fossil fuel consumption and the flooding of the sava river. romić & romić (2003) found that copper is characterized by a strongly scattered anthropogenic influence, particularly related to the uncontrolled waste dumps of liquid waste from households or agricultural enterprises. in addition, the same authors concluded that part of the area with the highest determined concentrations of zn, pb and cd was repeatedly flooded. hence, the recent sedimentation of the river deposits exposed to pollution is a very probable cause of the accumulation of metals in an inundation area. according to sollito et al. (2010), variation in the metal concentrations in the topsoil of the zagreb area has both natural and anthropogenic origins. in all the aforementioned studies, ptms were analyzed without using sorption modelling. ružičić et al. (2016), studied the sorption of pb, zn and cd in fluvisols. the highest sorption was determined in surface hori zons with higher cec, while the difference in sorption between indi vidual metals was small. in addition, ružičić & jašaragić-rako (2017) found that the sorption of pb, cd, cu and zn decreases with depth in fluvisols. our research enabled comparison of the sorption parameters of selected ptms in two texturally different soil types. the main objectives of the investigation were: (1) to determine the sorption characteristics of zn, cu and cd, using batch laboratory experiments; (2) to build ptm isotherms, valid for the investigated soils types; (3) to gain information about the sorption affinities of selected ptms for the investigated soils and between topsoil (shallow) and subsoil (deep) horizons; (4) to estimate the potential of groundwater contamination in the study area by selected ptms. 2. materials and methods 2.1. study area, investigated soils, field work the study area is situated in nw croatia (fig. 1), covering 350 km2, including the zagreb metropolitan area with its surroundings. the relief is flat and low, while the climate is humid continental, with annual means for precipitation and temperature of around 850 mm and 11 ºc, respectively. natural vegetation, which generally consists of meadows and deciduous forests, is largely cleared for agricultural land use. three types of deposits dominate in the zagreb aquifer system: sands, gravels and silts/ silty clays, deposited mainly during the pleistocene and holocene (velić & saftić, 1991). on these deposits, several types of soil have formed, with fluvisols and eutric fluvic cambisols as the dominant ones, and gleysols and fluvic phaeozems as subordinate soils (iuss working group wrb, 2014). fluvisols form a belt a few km wide along the sava river (as well as some narrow belts along the smaller streams). given that most of these soils have been protected from flooding, they now have a moderately developed a (or ap) horizon overlying several fluvial layers that are often separated one from another by a lithic discontinuity. in some specific the a horizon is fully developed, and fluvisols grade into fluvic phaeozems. fluvisols of the area are largely well-drained loams (or even sandy loams) with highly fluctuating groundwater that may rise into the top 1 m of the soil profile. generally, they are calcareous throughout and accordingly, slightly alkaline. gleysols are poorly drained soils that are saturated with surface water and/or groundwater for long enough periods in order to develop reducing conditions and gleyic properties, which characterize their morphology. they form in the low-lying landscape positions, which enable prolonged ponding and/or high groundwater table levels, where they are often associated with fluvic stagnic phaeozems. both these soils usually have a notably finer texture in comparison with fluvisols and fluvic phaeozems. eutric fluvic cambisols have a b horizon (cambic horizon) underlying the a horizon. cambic horizons are diagnosed due to the evidence of pedogenic alteration, (removal of carbonates, soil structure formation, increase in clay and/or fe content, etc.). cambisols in the study area are mainly loams or clay loams with good drainage. in general, they are non-calcareous, neutral to slightly acid (by definition having a ph >5.5). field research was conducted on four soil profiles (fig. 1). according to the wrb system, profiles 1 and 2 were classified as fluvisols, profile 3 as a gleysol, and profile 4 as a cambisol. as expected, the fluvisols were texturally finer (siltic) than the two remaining soils (loamic). profile 1 is a calcaric fluvisol (siltic) with the following horizon sequence according to fao (2006): a-ac-2cl-3cl-4clr/cl-5clr. profile 2 is a calcaric fluvisol (humic, siltic), with horizons a-2ac1-2ac2-3c1-3c24ac-5ac-5c. profile 3 is a calcaric fluvic stagnic gleysol (abruptic, hyperhumic, loamic): a-2ag-2ag2-2acg-3acl, whereas g eologia c roatica kovač et al.: sorption of cadmium, zinc and copper in dominant soils of the zagreb aquifer system, croatia 179 the profile 4 is a eutric fluvic cambisol (loamic, raptic): a-2b3bc. at the profile 1 site, a pedological pit was excavated up to 210 cm deep and detailed sampling and soil descriptions were undertaken (ružičić et al., 2016). a similar field investigation was conducted at the profile 4 site. there, the soil is 90 cm deep. regarding soil profiles 2 and 3, the field research consisted of borehole drilling using an auger probe (instead of pit excavation). soil profiles 2 and 3 are 190 and 110 cm deep respectively. in total, 22 bulk soil samples for laboratory analyses and experiments were collected from the four soil profiles. 2.2. methods soil samples were air-dried and passed through a 2 mm sieve for laboratory analyses and experiments. soil ph was measured in the potassium chloride solution (kcl) with a 1:2.5 soil to solution ratio (iso 13536, 2005) using wtw 340 and a ph meter. the electrical conductivity of soils was measured in water with a 1:5 soil to water ratio using a mettler toledo mpc 227 ec meter. carbonate content was determined gas-volumetrically using a scheibler apparatus (head, 1992), while organic matter was determined using hydrogen peroxide solution. the cation exchange capacity (cec) was determined using barium chloride solution (iso 13536, 1995). sorption isotherms for the soluble forms of copper (cu), cadmium (cd), and zinc (zn) were established for twenty-two bulk soil samples. the experiment was conducted with three replicates with relative standard deviation of 5%. sorption isotherms were obtained for each soil sample by equilibrating 0.5 g soil with 50 ml of solutions containing concentrations of 10, 20, 30, 40 and 50 mg/l of all the analyzed elements in the same concentrations. ptms were added to the solutions in the form of sulphates (cuso4×5h2o, znso4), and chloride (cdcl2). soils were equilibrated for 24 h by shaking at room temperature. suspensions were then centrifuged at 3000 rpm for 20 min, and the ptm concentrations in the equilibration solution were measured by atomic absorption spectrometry (aas) (instrument perkin elmer aanalyst 700). the amount of ptms sorbed by the soil was calculated using the following equation according to oecd (2000): s c c v w o e= − ×( ) (1) where s is the adsorbed amount of metal per unit weight of soil (mg/g), c0 the initial concentration of metal in the solution (mg/l), ce the equilibrium concentration of metal in the solution (mg/l), v the solution volume (l) and w the weight of air-dried soil (g). the corresponding sorption isotherms for each ptm were quantitatively described by parameters through fitting the experimental data to the freundlich isotherms. a simple linear relationship between the solution and adsorbed phases can be described by the equation: s k cd e= (2) where s is the amount of solute adsorbed onto the solid phase (mg/g), kd the slope of the isotherm, often referred to as the distribution coefficient (l/g). figure 1. zagreb aquifer boundary with the location of soil profiles. g eo lo gi a c ro at ic a geologia croatica 75/1180 the basic form of the freundlich isotherm equation is defined as follows: s k cf e a= (3) where kf (l/g) is a partitioning coefficient and is a measure of the affinity of a heavy metal to a soil and is widely reported in the literature for various chemicals. the parameter a is dimensionless and provides information on the degree of heterogeneity of the sorption sites (selim et al., 1992). as a approaches 0, surface site heterogeneity increases, and as a approaches 1 surface site homogeneity also increases. the relative sorption capacity (rsc) was also used to compare the metal sorption capacity of the samples (xiong et al., 2005). the rsc can be calculated by taking the difference between the initial and equilibrium metal concentrations, then dividing this difference by the initial metal concentration, and then expressing this as a percentage: rsc c c c o e o = − ⋅ ( ) 100 (4) all parameters were evaluated using descriptive statistics, namely minimum, maximum, average values, median, box-plots and correlation analysis using statistica 13.5.0.17. (tibco software inc., 1984-2018). calculation of isotherms was undertaken in microsoft© excel. a research area map (fig.1) was produced in arcmap 10.1 and a geocoded terrain (orthophoto) image was obtained from the geoportal of the croatian geodetic administration. figure 2. box plots of sand, silt and clay content in siltic soils (s), loamic soils (l), topsoil (shallow) and subsoil (deep) horizons. table 1. selected physicochemical properties of the investigated soils. electrical conductivity (ec); cation exchange capacity (cec); organic matter (om). soil profiles soil horizons om (%) ph (kcl) ec (µs/cm) carbonates (mass. %) cec (meq/100g) profile 1 (f) a 6.32 7.28 173 34.12 18.47 ac 2.68 7.37 129 35.02 18.51 2cl 1.17 7.36 89 41.29 8.11 3cl 1.25 7.39 99 41.29 9.56 4clr/cl 1.25 7.47 74 40.24 10.16 5cr 1.42 7.45 91 42.99 10.67 profile 2 (f) a 8.86 7.34 197.9 18.76 26.19 2acl 2.84 7.34 131.5 20.82 25.72 2ac2 3.1 7.47 155.1 24.66 23.67 3cl 1.05 7.52 170.7 32.31 22.66 3c2 0.75 7.58 139.5 34.12 22.22 4ac 4.97 7.53 164 34.6 23.26 5ac 3.03 7.60 103.3 36.1 23.15 5c 0.77 7.66 139.7 34.76 22.79 profile 3 (c) a 8.98 6.36 147.2 16.77 34.43 2ag 10.18 6.57 287 15.9 31.74 2ag2 9.19 7.05 286.33 22.94 37.48 2acg 7.97 6.93 364.67 21.25 24.63 3acl 7.16 6.47 395 6.73 19.55 profile 4 (c) a 5.35 6.49 117.27 1.10 29.01 2b 2.07 5.36 49.83 0.80 28.74 3bc 3.32 5.74 58.07 0.75 21.50 average 4.26 7.12 162.97 25.31 22.37 median 3.07 7.35 140.15 28.49 22.97 maximum 10.18 7.66 395.00 42.99 37.48 minimum 0.75 5.90 49.80 0.70 8.11 g eologia c roatica kovač et al.: sorption of cadmium, zinc and copper in dominant soils of the zagreb aquifer system, croatia 181 3. results 3.1. soils characterization results of the particle size analysis (soil texture) for the investigated soil profiles were previously published in ružičić et al. (2019a). the sand content varies from 3.18% to 56.33%, while silt content ranges from 38.23% to 87.43%, and the clay content varies from 5.44% to 41%. average percentages for sand, silt and clay contents are 21.69%, 58.67% and 19.65%, while the median values are 17.15%, 55.17% and 12.96% respectively (ružičić et al., 2019a). comparing particle size distribution between different soil types and between topsoil and subsoil horizons, it can be seen (fig. 2) that the sand content is the highest in siltic soils (s) and in subsoil horizons. silt content is the highest in siltic soils and in the topsoil horizons, while clay content is the highest in loamic soils (l) and in topsoil horizons (fig. 2). physicochemical characteristics of the analyzed soils are summarized in table 1. om varies from 0.75% to 10.18%, with average and median values of 4.26% and 3.07%, respectively. values of ph range from 5.90 to 7.66, with average and median values of 7.12 and 7.35. cec values range from 8.11 meq/100 g up to 37.48 meq/100 g, with average and median values of 22.37 and 22.97 meq/100 g. carbonate content varies from 0.7% to figure 3. box plots of om, ph, cec, ec and carbonate content in siltic soils (s), loamic soils (l), topsoil (shallow) and subsoil (deep) horizons. g eo lo gi a c ro at ic a geologia croatica 75/1182 42.99%, with average and median values of 25.31% and 28.49%. ec values range from 49.80 µs/cm up to 395 µs/cm with average and median values of 162.97 and 140.15 µs/cm. figure 3. shows that om values are significantly higher in loamic soils and in topsoil horizons in comparison with siltic soils and deeper horizons. a similar pattern can be observed for cec values, although differences in cec values between soil profiles and horizons are less pronounced. ec values are also higher in loamic soils and topsoil horizons, while the highest values of carbonates and ph are observed in siltic soils and in deeper horizons. organic matter (om) content of profile 1 ranges from 1.17 % (68-110 cm) to 6.32% (0-19 cm). its carbonate content (calcite and dolomite) ranges from 34.12% (0-19 cm) to 42.99% (190-210 cm). the highest cec value was 18.5 meq/100 g in the two upper soil horizons of this profile, which is in line with the contents of om (table 1). content of om in profile 2 ranges from 0.75 % (100-120 cm) to 8.86 % (0-30 cm) and shows an irregular depth-related trend (table 1). the highest cec values (approx. 26 meq/100g) were determined in the two upper soil horizons, which is comparable with the results for profile 1. carbonate content (calcite and dolomite) in profile 2 ranges from 18.76% (0-30 cm) to 36.10% (150170 cm), generally increasing with depth and being in line with its distribution in the profile 1 (table 1). the siltic soils (profiles 1 and 2) have a high content of carbonates which corresponds with their alkaline ph values, ranging from 7.28 to 7.66. electrifigure 4. freundlich sorption isotherms for profile 1: a) cu; (b) cd; (c) zn. figure 5. freundlich sorption isotherms for profile 3: a) cu; (b) cd; (c) zn. g eologia c roatica kovač et al.: sorption of cadmium, zinc and copper in dominant soils of the zagreb aquifer system, croatia 183 cal conductivity (ec) generally decreases with depth in these two soils (table 1). distribution of om in profile 3 ranges from 7.16% (80-110 cm) to 10.18 % (20-40 cm) while through profile 4 it ranges from 2.07 % (15-55 cm) to 5.35 % (0-15 cm) (table 1). in the upper three horizons of profile 3, the highest values of organic matter were measured, as well as the highest values of cec, compared to other profiles. the high cec values (approx. 29 meq/100g) were determined in the upper two soil horizons of the profile 4 (table 1). carbonate content in profile 4 is generally very low, being slightly higher in the topsoil (1.10%) than in the underlying soil horizons (table 1). this is not in line with results from profile 3 (table 1). in profile 3, the content of carbonates increases from the two topsoil horizons (16.8% and 15.9%) to the two middle horizons (22.9% and 21.3%), and then sharply decreases at the bottom of the profile (6.7%). in comparison to the siltic soils, the loamic soils (profiles 3 and 4) have lower carbonate contents. accordingly, they both have lower ph values – profile 3 is slightly acid to neutral, whereas profile 4 is slightly acid (table 1). also, in profile 3, soil ec shows an increasing trend with soil depth, which is not the case in the remaining profiles (table 1). ec distribution in profile 4 is similar to profiles 1 and 2 which can be matched with cec values (table 1). 3.2. sorption of ptms results of the competitive batch sorption experiments for all soil profiles are shown in table 2 and figures 4-7. based on the results figure 6. freundlich sorption isotherms for profile 3: a) cu; (b) cd; (c) zn. figure 7. freundlich sorption isotherms for profile 4: a) cu; (b) cd; (c) zn. g eo lo gi a c ro at ic a geologia croatica 75/1184 of sorption experiments, freundlich’s parameter and coefficients of determination (r-squared) for selected ptms were calculated. in fig. 8 it can be seen that the sorption values capacity of all ptms have greater variability in siltic soils and in the subsoil horizons. however, outliers are only present for all ptms in topsoil horizons. if median sorption values are examined based on the type of soil and depth, separately for each ptm, it can be seen that there is only a small difference. however, it can be seen that the median values of cu sorption are approximately twice as high as the median values of the sorption of zn and cd. in tables 4 and 5, correlation analyses of soil texture parameters, physicochemical characteristics and sorption parameters are shown for all the analyzed soils. in siltic soils (table 4) it can be seen that the sorption parameters of selected ptms are negatively correlated with ph, percentage of clay and cec values, and positively with carbonate content. when evaluating freundlich’s partitioning coefficient (kf) and distribution coefficient (kd), it can be seen that they are mostly negatively correlated with ph values, and in case of cd, with cec values. organic matter contents are negatively correlated with percentages of sand values and carbonate contents, and positively with percentages of silt and ec values. similarly, cec values are negatively correlated with percentages of sand values and carbonate content and positively with percentages of silt and ec values. however, the positive correlation between cec values and om content is not statistically significant. for loamic soils (table 5), results of correlation analysis are different in comparison to siltic soils. rsc for all selected ptms, as well as kfs values, are positively correlated with ph values om and carbonate contents and ec values. also, carbonate contents are positively correlated with om contents while cec values are positively correlated with percentages of silt values. 4. discussion the highest ptm amounts are retained by the shallowest soil depth range (0-19 cm) from profile 1 (fig. 4, table 3). rsc values of cu, zn and cd are above 97%, 85% and 75% respectively at this soil depth range. these results are consistent with results of previous research (ružičić et al., 2016; ružičić & jašaragić-rako, 2017), probably due to the high contents of silt, clay and om and high cec values (table 1). furthermore, it can be seen that the median value of cu sorption is much higher in comparison with the median values for zn and cd (fig. 8). the sorption capacity of soils has been found to be affected by several factors, including: cec, texture, ph, redox potential, clay content and mineralogy, organic matter, fe and mn oxides and carbonate content (bradl, 2004). our results show increased affinity for sorption (table 3, figs. 4 and 5) in topsoil horizons of siltic soils (profiles 1 and 2), which can be explained by the fact that these soil materials have the highest cec values and present excellent conditions for the sorption of ptms. the sorption affinity is not table 2. freundlich adsorption parameters for the analyzed ptms. profiles cu zn cd depth (cm) kf (*kd) (l/g) r2 kf (l/g) r2 kf (l/g) r2 profile 1 a 2.882* 0.76 1.4559 0.95 1.3033 0.90 ac 3.1831* 0.96 1.0658 0.89 0.9293 0.99 2cl 2.8387* 0.86 0.6732 0.67 0.618 0.97 3cl 0.8708* 0.90 0.8081 0.89 0.6793 0.98 4clr/cl 0.9665* 0.90 0.8603 0.80 0.6972 0.98 5cr 1.0113* 0.70 0.7434 0.75 0.6268 0.97 profile 2 a 2.4658 0.95 0.4472 0.99 0.2634 0.99 2acl 1.9378 0.91 0.4803 0.98 0.2897 0.96 2ac2 1.7707 0.92 0.4375 0.86 0.2699 0.91 3cl 1.477 0.95 0.3654 0.78 0.1935 0.93 3c2 1.5403 0.94 0.4176 0.51 0.2218 0.95 4ac 1.5746 0.94 0.3869 0.98 0.2191 0.99 5ac 1.4929 0.99 0.3356 0.88 0.1748 0.98 5c 1.4676 0.95 0.3804 0.92 0.1943 0.99 profile 3 a 1.576 0.98 0.5021 0.99 0.3844 0.95 2ag 1.8821 0.98 0.5742 0.99 0.3676 0.90 2ag2 2.5159 0.99 0.6054 0.99 0.3536 0.75 2acg 1.9118 0.98 0.5834 0.93 0.3293 0.88 3acl 1.614 0.99 0.5346 0.97 0.2846 0.82 profile 4 a 1.6695 0.97 0.3663 0.97 0.2274 0.99 2b 0.38 0.74 0.1058 0.97 0.0953 0.99 3bc 0.8821 0.83 0.1634 0.95 0.0899 0.96 table 3. relative sorption capacity (rsc) in percentages. relative sorption capacity (rsc) (%) profile soil horizons cu zn cd profile 1 a 97.68 85.01 74.86 ac 96.13 81.49 63.45 2cl 95.84 73.55 39.98 3cl 88.97 76.07 46.19 4clr/cl 88.91 77.40 47.05 5cr 90.18 75.38 42.42 profile 2 a 49.52 29.80 25.93 2acl 49.21 28.14 25.06 2ac2 48.95 24.70 22.33 3cl 48.41 20.52 17.79 3c2 48.52 21.48 16.78 4ac 48.63 22.67 18.67 5ac 48.30 19.78 17.20 5c 48.36 20.72 18.06 profile 3 a 48.01 28.29 24.11 2ag 48.96 31.09 25.24 2ag2 49.61 32.42 24.34 2acg 49.09 29.94 22.24 3acl 48.20 27.60 21.24 profile 4 a 48.72 27.55 25.80 2b 41.93 17.12 18.75 3bc 41.07 17.22 15.78 g eologia c roatica kovač et al.: sorption of cadmium, zinc and copper in dominant soils of the zagreb aquifer system, croatia 185 changed through soil depth in profiles 1 and 2 for cu and zn, which is not the case for cd. fontes et al. (2000) observed similar sorption behaviour for ptms in soils enriched with carbonate minerals. their results indicated that the presence of carbonates in the soil created new sorption sites and also favoured the precipitation of cu and zn. in the analyzed soils, the presence of carbonate minerals led to an elevated ph level (table 1) which may have enhanced ptm figure 8. box-plots of cu, zn and cd sorption with respect to siltic soils (s), loamic soils (l), topsoil (shallow) and subsoil (deep) horizons. table 4. correlation analysis of soil texture parameters, physicochemical characteristics and sorption parameters in siltic soils (significant results at p < 0.05 marked in red). ph sand silt clay om cec carbonate ec cu sorption zn sorption cd sorption cu kd (kf) zn kf cd kf ph 1.00 sand (%) 0.22 1.00 silt (%) -0.33 -0.99 1.00 clay (%) 0.52 -0.44 0.28 1.00 om (%) -0.47 -0.61 0.67 -0.10 1.00 cec (meq/100 g) 0.26 -0.79 0.74 0.53 0.45 1.00 carbonate (mass. %) 0.21 0.88 -0.90 -0.21 -0.59 -0.81 1.00 ec (µs/cm) -0.10 -0.66 0.67 0.18 0.67 0.77 -0.72 1.00 cu sorption (%) -0.58 0.48 -0.41 -0.57 -0.13 -0.84 0.62 -0.51 1.00 zn sorption (%) -0.62 0.42 -0.34 -0.56 -0.07 -0.82 0.57 -0.48 0.99 1.00 cd sorption (%) -0.69 0.14 -0.07 -0.42 0.15 -0.56 0.35 -0.20 0.91 0.93 1.00 cu kd (kf) (l/g) -0.42 -0.17 0.25 -0.38 0.44 0.03 -0.09 0.35 0.34 0.30 0.46 1.00 zn kf (l/g) -0.65 0.13 -0.07 -0.34 0.16 -0.50 0.34 -0.14 0.86 0.88 0.99 0.45 1.00 cd kf (l/g) -0.59 0.21 -0.16 -0.34 0.13 -0.54 0.43 -0.20 0.88 0.89 0.98 0.46 0.98 1.00 g eo lo gi a c ro at ic a geologia croatica 75/1186 carbonate precipitation reactions. in addition, imtiaz et al. (2006) found that most of the added zn is held in the caco3 pool in alkaline soils, whereas in acidic soils zn mostly occurs in exchangeable form. our sorption data suggest that cu and zn may precipitate as carbonate phases in the fluvisols due to calcite dissolution, which was previously explained by sipos (2009). the correlation analysis from table 4 shows moderate positive correlation between cu, zn and carbonate content in profiles 1 and 2 (siltic soils), which suggests similar sorption behaviours of cu and zn, as confirmed by sipos (2009). in addition, correlation analysis between cd sorption and carbonates shows a lower correlation (0.35), which is not statistically significant and can be attributed to the precipitation of cdco3 that occasionally occurs in sandy soils with low cec and organic matter and alkaline ph (bradl, 2004). freundlich’s partitioning coefficient (kf) and distribution coefficient (kd) represent the sorption affinity of the metal cations in solution for the soil solid phase and can be used to characteri ze the mobility and retention of ptms in a soil system. low kf and kd values indicate that most of the ptms present in the soil system remain in solution and are available for transport, chemical processes and plant uptake (jalali & moharrami, 2007). in addition, higher values of kf and kd indicate lower mobility and higher retention or sorption of ptms in the soil. the distribution coefficient for cu (profile 1) and partitioning coefficients for other ptms are higher in first two horizons of profiles 1 and 2 (siltic soils), which is in line with the sorption of ptms (table 3). it can be explained with high values of om and cec in these topsoil horizons. although the distribution coefficient (kd) of cu is in positive moderate correlation (0.44) with the om content in our study, it is not statistically significant (table 4). however, it has been shown that the sorption characteristics of cu are enriched in soils with higher om content (ma et al., 2010; zemanová et al., 2014; gonzâlez-costa et al., 2017; elbana & selim, 2019). soil organic matter can enhance the adsorption of cu by the soils through the formation of complexes between this metal and the active groups of the organic matter (guo et al., 2006; minkina et al., 2017). the highest ptm amounts in profile 3 are retained at the third soil depth range (40-60 cm) (fig. 6, table 3). cu showed retention of 49 %, zn of 32 %, while only 24 % of cd is sorbed at this soil depth range. comparing rsc values among the studied soil profiles, most of the ptms are retained at the topsoil horizons, which is unusual, but can be explained by the fact that these soil materials consisted of finer particles (at the depth of 40-60 cm) and have the highest cec values and om content (table 1). elbana et al. (2018) found that soils with high om and cec values exhibited strong sorption for ptms. in addition, correlation analysis from table 5 confirmed, apparently, strong positive correlation between all ptms sorption affinity, freundlich’s partitioning coefficient (kf) and om content (from 0.74 to 0.98). these results suggest that at this soil profile sorption of ptms is more related to the silt fraction, rather than clay, which corresponds to the results of ružičić et al. (2019b), who found that zn is strongly positively correlated with the silt component in loamic soils. in profile 4, the sorption pattern is completely different from profile 3 (fig. 7, table 3), with the highest sorption values of all ptms in the topsoil horizon. cu sorption capacity is above 48%, zn is above 27 %, while 26% of cd is sorbed at this soil depth range. from these results it can be seen that cd and zn have similar sorption affinities. the om and cec values are the highest in this soil horizon, which is in correspondence with profile 3. according to ružičić et al. (2019a), this soil has a minimum content of sand material at subsurface soil depths, which also favours a higher affinity for ptms sorption. all results suggest that the main physicochemical property of soil for ptm sorption in loamic soils is organic matter. the result of the sorption experiments in texturally different soils confirmed that soil sorption decreased in the order cu > zn > cd, which is consistent with results reported by other authors (covelo et al., 2008; vidal et al., 2009; dişli, 2010; trakal et al., 2012; elbana & selim, 2019). the comparison of all ptm sorption isotherms (figs. 4 to 7) in the analyzed soil profiles revealed that cu has the highest sorption affinity, which is confirmed with relevant partitioning and distribution cotable 5. correlation analysis of soil texture parameters, physicochemical characteristics and sorption parameters in loamic soils (significant results at p < 0.05 marked in red). ph sand silt clay om cec carbonate ec cu sorption zn sorption cd sorption cu kf zn kf cd kf ph 1.00 sand (%) -0.04 1.00 silt (%) -0.01 0.03 1.00 clay (%) 0.03 -0.85 -0.55 1.00 om (%) 0.63 -0.20 0.46 -0.08 1.00 cec (meq/100 g) 0.27 -0.12 0.81 -0.32 0.47 1.00 carbonate (mass. %) 0.63 -0.42 0.43 0.12 0.85 0.53 1.00 ec (µs/cm) 0.62 -0.42 -0.17 0.45 0.70 -0.12 0.63 1.00 cu sorption (%) 0.79 -0.06 0.33 -0.12 0.86 0.39 0.69 0.76 1.00 zn sorption (%) 0.81 -0.15 0.36 -0.06 0.93 0.46 0.79 0.76 0.98 1.00 cd sorption (%) 0.61 0.07 0.60 -0.37 0.74 0.63 0.52 0.42 0.89 0.86 1.00 cu kf (l/g) 0.91 -0.13 0.19 0.01 0.87 0.43 0.79 0.72 0.90 0.95 0.74 1.00 zn kf (l/g) 0.75 -0.23 0.25 0.06 0.95 0.31 0.84 0.86 0.93 0.97 0.72 0.92 1.00 cd kf (l/g) 0.62 -0.13 0.52 -0.16 0.98 0.50 0.85 0.69 0.90 0.94 0.80 0.84 0.95 1.00 g eologia c roatica kovač et al.: sorption of cadmium, zinc and copper in dominant soils of the zagreb aquifer system, croatia 187 efficients. this can be also seen in fig. 8, where the median value for cu sorption in both soil groups (siltic and loamic) and at both soil horizons (topsoil and subsoil) is higher than for zn and cd. alternatively, if sorption of ptms is evaluated separately, based on soil texture and horizon depth, it can be seen that the analyzed soils have similar median sorption values which is unusual with respect to their genesis and formation. however, a greater variability of sorption is observed in siltic soils and in deeper horizons. comparable results were obtained by sangiumsak & punrattanasin (2014), who reported that all analyzed soils in their research have a similar adsorption capacity. our research indicates that ph, carbonate content (minerals) and om are the most important soil properties influencing the sorption of analyzed ptms. all topsoil horizons, with higher sorption affinities, are neutral to slightly alkaline (6.49-7.34). in general, soils with higher ph indicate better adsorption processes due to reduced concentrations of h+ in the solution. nevertheless, the sample composition and affinity of ptms also influence the adsorption processes. therefore, the adsorption capacities of soils increased with increasing ph value. soil colloids with a negative charge and ptms with a positive charge effectively increase the adsorption capacity of soil. according to he et al. (2020), the adsorption of heavy metals in soils increased with increasing caco3 content. in addition, soils with high organic matter and soils with high ph, due to the presence of carbonates, exhibited strong sorption for all heavy metals (elbana & selim, 2019). our sorption data indicates that zn and cu in siltic soils are mostly affected by ph and carbonate content due to their precipitation as carbonate phases. this process was documented previously by other studies (imtiaz, et al., 2006; sipos, 2009; he et al., 2020). it is interesting to note that only in topsoil horizons of the analyzed soils were outliers and higher sorption values discovered. ružičić et al. (2019a) found that smaller particles (clay and smaller fraction of silt) prevailed at the topsoil horizons of analyzed soils. these extreme values can be partly attributed to higher cec and om values and mainly clay minerals at these soil depths. clay mineralogy and also fe and mn oxyhydroxides can contribute to higher sorption values in topsoil horizons of analyzed soils. according to previous studies (vertačnik et al., 1997; ružičić et al., 2019b), these types of soils in the research area have increased contents of chlorites and vermiculites which are clay minerals with a higher affinity for ionic sorption. in addition, ružičić et al. (2016) found increased content of fe and mn oxyhydroxides in subsurface soil depths of fluvisols. the zagreb aquifer system, where groundwater is naturally stored, is currently under threat due to decreasing water quantity and increasing concentrations of pollutants such as ptms (nakić et al., 2013). our results reveal that sorption of ptms is well represented in the first three depth bands of the analyzed soils. from an environmental point of view, ptms are retained in the upper soil horizons and their transport to the saturated zone is limited. this finding is favourable for the protection of groundwater within the zagreb aquifer system. zinc and copper probably do not present toxicity to soils and groundwater in the study area. this is not the case for cd, which is the most mobile of all three analyzed ptms. our results indicate the relatively high leaching potential of cadmium from soil to groundwater, which is consistent with the results of previous researches conducted in the zagreb area (romić, 2002; romić & romić, 2003) that show increased concentration of cadmium along the investigated soil profiles. accordingly, future research of the behaviour of ptms in soil and groundwater of the zagreb aquifer system should be focused on characterization of pollution sources and transport of cd at depth in order to assess the risk of groundwater contamination. 5. conclusions the maximum values of freundlich’s partitioning coefficient (kf) and distribution coefficient (kd) were determined for the first three depth ranges of the studied soils for all analyzed ptms. our results indicate that sorption of ptms is influenced more by soil physicochemical characteristics at different soil depths than by soil type per se, which is confirmed with the higher affinity of zn and cd bonding in the topsoil horizons. all analyzed soils showed adsorption capacity in the order of cu > zn > cd. zinc and copper probably do not present a toxicity threat to soils and the zagreb aquifer. this is not the case for cd which is the most mobile of the three analyzed ptms. also, it has been shown that the sorption capacity values of all ptms have greater variability in siltic soils and in the subsoil horizons. this suggests that sorption of ptms is influenced more by the physicochemical characteristics at different soil depths than by soil type. accordingly, regular monitoring of cd concentrations with depth in soils of the zagreb aquifer system is needed in order to quantify leaching of cadmium through the soil to the groundwater and to evaluate the risk of groundwater contamination by moderate to highly mobile ptms. references adriano, d.c. (2001): trace elements in terrestrial environments: biogeochemistry.– springer, new york, 867 p. appel, c. & ma, l. (2002): concentration, ph, and surface charge effects on cadmium and lead sorption in three tropical soils.– journal of environmental quality, 31, 581–589. doi: 10.2134/jeq2002.5810 besnard, e., chenu, c. & robert, m. (2001): influence of organic amendments on copper distribution among particle-size and density fractions in champagne vineyard soils.– environmental pollution, 112, 329–337. doi: 10.1016/s02697491(00)00151-2 bonten, l.t.c., romkens, p.f.a.m. & brus, d.j. (2008): contribution of heavy metal leaching from agricultural soils to surface water loads.– environmental forensics, 9, 252–257. doi: 10.1080/15275920802122981 bradl, h.b. (2004): adsorption of heavy metal ions on soils and soils constituents.– journal of colloid and interface science, 277/1, 1–18. doi: 10.1016/j. jcis.2004.04.005 covelo, e.f., matías j.m., vega f.a., reigosa m.j. & andrade m.l. (2008): a tree regression analysis of factors determining the sorption and retention of heavy metals by soil.– geoderma, 147, 75–85. doi: 10.1016/j.geoderma.2008.08.001 dişli, e. (2010): batch and column experiments to support heavy metals (cu, zn and mn) transport modeling in alluvial sediments between the mogan lake and the eymir lake gölbaşi, ankara.– groundwater monitoring and remediation, 30/3, 125–139. doi: 10.1111/j.1745-6592.2010.01302.x durn, g., miko, s., čović, m., barudžija, u., tadej, n., namjesnikdejanović, k. & palinkaš, l. (1999): distribution and behaviour of selected elements in soil developed over a historical pb–ag mining site at sv. jakob, croatia.– journal of geochemical exploration, 67/1–3, 361–376. doi: 10.1016/ s0375-6742(99)00064-3 elbana, t.a., selim, h.m., akrami, n., newman, a., shaheen, s.m. & rinklebe, j. (2018): freundlich sorption parameters for cadmium, copper, nickel, lead, and zinc for different soils: influence of kinetics.– geoderma, 324, 80–88. doi: 10.1016/j.geoderma.2018.03.019 elbana, t.a. & selim, h.m. (2019): modeling of cadmium and nickel release from different soils.– geoderma, 338, 78–87. doi: 10.1016/j.geoderma.2018.11.041 fao (2006): guidelines for soil description, 4th edition. fao, rome. fontes, m.p.f., de matos, a.t., da costa, l.m. & neves, j.c.l. (2000): competitive adsorption of zinc, cadmium, copper, and lead in three highly weathered brazilian soils.– communications in soil science and plant analysis, 31, 2923–2958. doi: 10.1080/00103620009370640 g eo lo gi a c ro at ic a geologia croatica 75/1188 gonzâlez-costa, j.j., reigosa, m.j., matías j.m. & fernández-covelo, e. (2017): analysis of the importance of oxides and clays in cd, cr, cu, ni, pb and zn adsorption and retention with regression trees.– plos one, 12/1, 1–25. doi: 10.1371/journal.pone.0168523 guo x.y., zhang, s.z., shan, x.q., luo, l., pei, z.g., zhu, y.g., liu, t., xie, y.n. & gault, a. (2006): characterization of pb, cu, and cd adsorption on particulate organic matter in soil.– environmental toxicology chemistry, 25/9, 2366–2373. doi: 10.1897/05-636r.1 he, g., zhang, z., wu, x., cui, m., zhang, j. & huang, x. (2020): adsorption of heavy metals on soil collected from lixisol of typical karst areas in the presence of caco3 and soil clay and their competition behavior.– sustainability, 12, 7315. doi: 10.3390/su12187315 head, k.h. (1992): manual of soil laboratory testing.– pentech press, london, 388 p. hough, r.l. (2010): copper and lead.– in: hooda, p.s. (eds.): trace elements in soils. wiley-blackwell publishing: west sussex, united kingdom, 441–461. doi: 10.1002/9781444319477.ch18 imtiaz, m., alloway, b.j., aslam, m., memon, m.y., khan, p., siddiqui, s. & shah, s.k.h. (2006): zinc sorption in selected soils.– communications in soil science and plant analysis, 37, 1675–1688. doi: 10.1080/00103620600710330 iso 10390 (2005): soil quality-determination of ph.– international organisation for standardisation, switzerland. iso 13536 (1995): soil quality-determination of the potential cation exchange capacity and exchangeable cations using barium chloride solution buffered at ph = 8,1.– international organisation for standardisation: geneva, switzerland. iuss working group wrb. (2014): world reference base for soil resources 2014: international soil classification system for naming soil and creating legends for soil maps; world soil resources report; fao: rome, italy, p.106. jalali, m. & moharrami, s. (2007): competitive adsorption of trace elements in calcareous soils of western iran.– geoderma, 140, 156–163. doi: 10.1016/j.geoderma.2007.03.016 lichner, l., dlapa, p., sir, m., cipakova, a., houskova, b., fasko, p. & nagy, v. (2006): the fate of cadmium in field soils of the danubian lowland.– soil & tillage research, 85, 154–165. doi: 10.1016/j.still.2005.01.011 ma, l., xu, r. & jun, j. (2010): adsorption and desorption of cu(ii) and pb(ii) in paddy soils cultivated for various years in the subtropical china.– journal of environmental sciences, 22/5, 689–695. doi: 10.1016/s1001-0742(09)60164-9 martinez, c.e. & motto, h.l. (2000): solubility of lead, zinc and copper added to mineral soils.– environmental pollution, 107, 153–158. doi: 10.1016/s02697491(99)00111-6 minkina, t.m., pinskii, d.l., bauer, t.v., nevidomskaya, d.g., mandzhieva, s.s. & sushkova, s.n. (2017): sorption of cu by chernozems in southern russia.– journal of geochemical exploration, 174, 107–112. doi: 10.1016/j.gexplo.2016.06.002 nakić, z., ružičić, s., posavec, k., mileusnić, m., parlov, j., bačani, a. & durn, g. (2013): conceptual model for groundwater status and risk assessment-case study of the zagreb aquifer system.– geologia croatica, 66/1, 55–77. doi: 10.4154/gc.2013.05 nan, z., li, j., zhang, j. & cheng, g. (2002): cadmium and zinc interactions and their transfer in soil-crop system under actual field conditions.– science of the total environment, 285, 187–195. doi: 10.1016/s0048-9697(01)00919-6 oecd (2000), test no. 106: adsorption -desorption using a batch equilibrium me thod, oecd guidelines for the testing of chemicals, section 1, oecd publishing, paris, https://doi.org/10.1787/9789264069602-en pietrzak, u. & mcphail, d.c. (2004): copper accumulation, distribution and fractionation in vineyard soils of victoria, australia.– geoderma, 122, 151–166. doi: 10.1016/j.geoderma.2004.01.005 romić, m. & romić, d. (2003): heavy metals distribution in agricultural topsoils in urban area.– environmental geology, 43, 795–805. doi: 10.1007/s00254-0020694-9 ruley, a.t., sharma, n.c., sahi, s.v., shree, s.r. & sajwan, k.s. (2006): effects of lead and chelators on growth, photosynthetic activity and pb uptake in sesbaniadrummondii grown in soil.– environmental pollution, 144, 11–18. doi: 10.1016/j.envpol.2006.01.016 ružičić, s., mileusnić, m., posavec, k., nakić, z., durn, g. & filipović, v. (2016): water flow and solute transport model of potentially toxic elements through unsaturated zone at regional wellfield kosnica.– hydrological processes, 30/22, 4113–4124. doi: 10.1002/hyp.10914 ružičić, s. & jašaragić-rako, t. (2017): multielement sorption of cadmium, zinc, copper and lead onto a fluvisol profile at the stara loza site, croatia.– international journal of environment and pollution, 62/1, 63–73. doi: 10.1504/ ijep.2017.088188 ružičić, s., kovač, z., perković, d., bačani, l. & majhen, lj. (2019a): the relationship between the physicochemical properties and permeability of the fluvisols and eutric cambisols in the zagreb aquifer, croatia.– geosciences, 9/10, 416. doi: 10.3390/geosciences9100416 ružičić, s., kovač, z. & borovčak, t. (2019b): possible influence of agriculture on an unsaturated zone in croatia.– polish journal of environmental studies, 28/6, 4341–4349. doi: 10.15244/pjoes/99305 sangiumsak, n. & punrattanasin, p. (2014): adsorption behavior of heavy metals on various soils.– polish journal of environmental studies, 23/3, 853–865. selim, h.m., buchter, b., hinz, c. & ma, l. (1992): modeling the transport and retention of cadmium in soils: multireaction and multicomponent approaches.– soil science society of american journal, 56/4, 1004–1015. doi: 10.2136/ sssaj1992.03615995005600040002x seuntjens, p., tirez, k., šimůnek, j., van genuchten, mth., cornelis, c. & geuzens, p. (2001): aging effects on cadmium transport in undisturbed contaminated sandy soil column.– journal of environment quality, 30, 1040–1050. doi: 10.2134/jeq2001.3031040x shaheen, s.m., tsadilas, c.d., mitsibonas, t. & tzouvalekas, m. (2009): distribution coefficient of copper in different soils from egypt and greece.– communications in soil science and plant analysis, 40, 214–226. doi: 10.1080/00103620802625625 sipos, p. (2009): single element and competitive sorption of copper, zinc and lead onto a luvisol profile.– open geosciences volume, 1/4, 404–415. doi: 10.2478/ v10085-009-0035-2 smolders, e. & mertens, j. (2013): cadmium.– in: alloway, b.j. (eds.): heavy metals in soils: trace metals and metalloids in soils and their bioavailability. springer, dordrecht, heidelberg, new york, london, 283–311. sollitto, d., romić, m., castrignano, a., romić, d. & bakić, h. (2010): assessing heavy metal contamination in soils of the zagreb region (northwest croatia) using multivariate geostatistics.– catena, 80, 182–194. doi: 10.1016/j. catena.2009.11.005 trakal, l., komárek, m., száková, j., tlustoš, p., tejnecký, v. & drábek, o. (2012): sorption behavior of cd, cu, pb, and zn and their interactions in phytoremediated soil.– international journal of phytoremediation, 14/8, 806–819. doi: 10.1080/15226514.2011.628714 vega, f.a., covelo, e.f. & andrade, m.l. (2008): a versatile parameter for comparing the capacities of soil for sorption and retention of heavy metals dumped individually or together: results for cadmium, copper and lead in twenty soil horizons.– journal of colloid and interface science, 327/2, 275–286. doi: 10.1016/j. jcis.2008.08.027 velić, j. & saftić, b. (1991): subsurface spreading and facies characteristics of middle pleistocene deposits between zaprešić and samobor.– geological bulletin, 44, 69–82. velić, j. & durn, g. (1993): alternating lacustrine-marsh sedimentation and subaerial exposure phases during quaternary: prečko, zagreb, croatia.– geologia croatica, 46/1, 71–90. vertačnik, a., barišić, d., musani, lj., prohić, e. & juračić, m. (1997): exchangeable fraction of elements in alluvial sediments under waste disposal site (zagreb, croatia).– journal of radioanalytical and nuclear chemistry, 218/1, 45–52. doi: 10.1007/bf02033972 vidal, m., santos, m.j., abrao, t., rodríguez, j. & rigol, a. (2009): model ling competitive sorption in a mineral soil.– geoderma, 149, 189–198. doi: 10.1016/j.geoderma.2008.11.040 xiong, x., stagnitti, f., turoczy, n., allinson, g., li, p., nieber, j., steenhuis, t.s., parlange, j.y., leblanc, m., ziogas, a.k., ferreira, a.j.d. & keizer, j.j. (2005): competitive sorption of metals in water repellent soils: implications for irrigation recycled water.– australian journal of soil research, 43/3, 351–356. doi: 10.1071/sr04086 zemanová, v., trakal, l., ochecová, p., száková, j. & pavlíková, d. (2014): a model experiment: competitive sorption of cd, cu, pb and zn by three different soils.– soil and water research, 9/3, 97–103. doi: 10.17221/50/2013-swr 2020 | 73/1 | 1–12 | 14 figs. | 3 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction ursus gr. spelaeus is one of the most important members of the faunal assemblage during the continental late pleistocene in eu­ rope and, consequently has been the subject of many publications. in order to establish the correct relationship among cave bears, ge­ netic analyses have been recently addressed by morphometric ana­ lyses with the result of creating some confusion in the elaboration of an accurate phyletic tree. in italy the greatest number of contri­ butions to this debate have been based on morphometric and mor­ phodynamic analyses, although lately genetic and chronological studies have gained attention, albeit in a lesser number with respect to those from foreign populations of cave bears (perego et al., 2001; orlando et al., 2002; bona, 2004; quiles, 2004; rossi et al., 2006; rossi & santi, 2005, 2007, 2011, 2012, 2013, 2015; rossi et al., 2018; santi & rossi, 2007, 2008, 2014; zunino & pavia, 2005; martini et al., 2014; ter­ lato et al., 2017, 2018). the most previously studied caves are those from lombardy and veneto in italy, whereas those from pied­ mont (sambughetto valstrona, grotta del bandito among the most important ones) have been only superficially analysed (e.g. zun­ ino & pavia, 2005; santi et al., 2005; santi & rossi, 2018). the aim of this study therefore is to analyse in detail the morphodynamics of cave bear teeth from the grotta del bandito (cuneo province) (bearing in mind that the morphodynamic indi­ ces are useful only to give an indication of the evolutionary level robu, 2016). this will also expand our knowledge on cave bears in an area of piedmont near the cave of basura (liguria) where more definitely “modern” bears have been observed with respect to those of other cave bear populations in northern italy (quiles, 2004). 2. grotta del bandito the grotta del bandito (cuneo province) along with the other caves located in valstrona (the most important being the grotta ursus gr. spelaeus from grotta del bandito (piedmont, northern italy). 1. morphodynamics of teeth and indications of an evolutionary step giuseppe santi*,1 and mario rossi2 1 university of pavia, dipartimento di scienze della terra e dell’ambiente, via ferrata 1, i-27100 pavia, italy; (*corresponding author: gsanti@unipv.it) 2 museo civico di storia naturale, lungadige di porta vittoria 9, i-37100 verona, italy; (mario.rush@tiscali.it) doi: 10.4154/gc.2020.03 abstract this study is focused on cave bears from the grotta del bandito (cuneo province, piedmont region, northern italy), especially their teeth. the morphodynamic analyses have been elaborated and compared with other cave bears from northern italy, and other cave bear taxa from particular european sites. the grotta del bandito bears are similar in size to other cave bears from italy, and no differences were observed with the other cave bear species or subspecies (e.g. u. ingressus, u. s. ladinicus, u. s. eremus). thus their inclusion in the u. gr. spelaeus is the most appropriate classification, and they show a simpler dental surface than the “modern” cave bears (i.e. ingressus). the question of whether a single species of spelaeus lived in north italy, is also introduced. in fact, the differences in size are probably the result of population variability, and no clear evidence of other spelaeoid species and/or subspecies, i.e. ingressus, s. ladinicus and s. eremus, was discovered. delle streghe) and in mount fenera, is an important site of cave bear remains in the piedmont region near the boundary with france. in the past, zunino & pavia (2005) conducted a su­ perficial survey of this cave which is geographically located on the right side of the valley of gesso (fig. 1a). its entrance is at 726 m a.s.l. and it is formed in the jurassic limestone. the cave is composed of an e­w corridor (217 m) and three major cavities along with others of smaller dimensions. zunino & pavia (2005) subdivided this cave into two parts with the same sedi­ mentary infills: the first, called the “eastern branch” is composed of a sand­clay with sedimentary pebbles, and the second one, very similar in the first part of the corridor to the “eastern branch”, occupies the western end (fig. 1b). these authors also conducted three profiles (called l, m and n respectively) (fig. 1c) in three different areas of the cave and discovered a vertebrate association listed in table 1. 3. materials and methods the studied teeth (table 2) are stored in the museo civico di sto­ ria naturale of milan (lombardy). all dentition types are present in the sample: incisors, canines, premolars and molars. this study uses the morphodynamics developed by rabeder (1999) and grandal d’anglade & lópez gonzález (2004). in his paper rabeder (1991) conceived and applied the morpho­ dynamic analysis on the p4/p4 only, and later elaborated it for the other teeth typologies, after having applied this method for the first time to the arvicolidae of the pliocene­pleistocene (rabeder, 1981). it was subsequently also proposed for the in­ cisors, premolars and molars of cave bears. the most important concept on which this morphodynamic method is based, is the evaluation over time of the development of the complication of the dental surface (from the simpler forms to the most compli­ cated and assigning each one a particular morphotype labelled article history: manuscript received juny 24, 2019 revised manuscript accepted january 23, 2020 available online february 29, 2020 keywords: ursus, teeth, grotta del bandito, italy, late pleistocene, evolution g eo lo gi a c ro at ic a geologia croatica 73/12 figure 1. grotta del bandito (cuneo, piedmont): a. geographic position of the site. b. plan of the cave and c. generalized profiles in the cave (modified after zunino & pavia, 2005). table 1. faunal list of the grotta del bandito (modified after: zunino & pavia, 2005). species l1 l4 m1 m3 m4 n1 n4 ursus spelaeus rosenmüller, 1794 xx xx xxx xx xx xxx x canis sp. x vulpes vulpes (linnaeus, 1758) x felis silvestris schreber, 1777 x mustela putorius linnaeus, 1758 x martes martes (linnaeus, 1758) x martes foina (erxleben, 1777) x capra ibex linnaeus, 1758 x rupicapra rupicapra linnaeus, 1758 x lepus sp. x castor fiber linnaeus, 1758 x microtus arvalis (pallas, 1778) xx microtus (terricola) cf. subterraneus (de sélys-longchamps, 1836) xx xx x clethrionomys glareolus (schreber, 1780) x xxx x apodemus cf. sylvaticus (linnaeus, 1758) x x x x glis glis (linnaeus, 1766) x xx x eliomys quercinus (linnaeus, 1766) x sorex araneus linnaeus, 1758 xx rhinolophus cf. ferrumequinum (schreber, 1774) x x with a letter from a to f which is associated with a morphody­ namic factor), and to correlate it with the cave bears evolutionary line (rabeder, 1991; 1999; rabeder & tsoukala, 1990; robu, 2016 etc.). figure 2 clearly explains the morphotype con­ cept for the p4/p4, the most important teeth in the evolutionary picture. moreover, the methods do not give absolute results, but being a quantitative analysis advance an indication only of the evolutionary step reached by the studied specimens (rabeder, 1991; robu, 2016). grandal d’anglade & lópez gonzález (2004) proposed a similar morphodynamic elabo­ ration to that of rabeder for m1. for the different components of this kind of tooth (paraconid, trigonid cusplets and talonid one) the so called “convergence index” is evaluated. as well as the morphodynamic index sensu rabeder, the main target of the table 2. number of the cave bears tooth specimens from the grotta del bandito (cuneo, piedmont) analysed in this work. for explanation see the text. tooth n. of specimens (in this work) i2 10 i2 4 i3 10 i3 8 p4 10 p4 6 m1 14 m1 27 m2 23 m2 28 m3 7 total 147 g eologia c roatica santi and rossi: ursus gr. spelaeus from grotta del bandito (piedmont, northern italy). 1. morphodynamics of teeth and indications ... 3 figure 2. morphodynamic indices of the p4/p4 (modified after rabeder, 1991). g eo lo gi a c ro at ic a geologia croatica 73/14 “convergence index” is to indicatively evaluate the evolutionary step reached by the cave bears. for a more complete and detailed overview we included the data analysed by zunino & pavia (2005) of part of the teeth discovered in this cave from and earlier preliminarily study. the following proposed considerations will be commented on and compared with the data of the cave bears from european caves in which recently different species and subspecies (ursus ingressus rabeder et al., 2004, u. spelaeus eremus rabeder et al., 2004, u. spelaeus ladinicus rabeder et al., 2004) have been identified. 4. morphodynamics of teeth incisors. studies on incisors are rather rare; frischauf (2014) studied the incisors from križna jama (slovenia), frischauf et al. (2014) those from drachenhöhle (mixnitz–styria) and baryshnikov et al. (2018) the incisors from the urals­cau­ casus mts. in these three caves, remains of u. ingressus and u. kudarensis baryshnikov, 1985 (the latter is described in lubine et al., 1985) were discovered and examined in greater detail. referring to the teeth from the bandito cave the morpho­ type “p” for the fossa lunaris–cingulum of i2 is the only one ob­ served; the standardized index (abbreviated “std”) is low (58.91). (for meaning of the “morphotype” see above). this can be a con­ sequence of a low number of specimens (n=10), which makes it impossible to indicate the evolutionary step of these teeth. also for i3 the low number of specimens (n=10) prevents any definite conclusions on their evolutionary level. however, some conside­ rations can be proposed: the kalyx distalis has “0” as the most frequent morphotype and only rarely (two teeth) the “1” one. the highest morphotypes are totally lacking. if this is confirmed, the evolutionary degree is rather low, but this deduction is thwarted by the scarcity of specimens. to conclude this short discussion on the morphodynamics of the incisors, all of the i2 have an “s” morphotype frequency typical of spelaeus (rabeder, 1999). in i3 the lowest morphotype of the sulcus mesialis is b/c and in contrast to the other incisors, the main type most frequently ob­ served is the “d” morphotype. in this case also the scarce speci­ mens (n=8) prevents a definitive conclusion, but if this is con­ figure 3. frequencies (%) of the p4/p4 morphotypes from the grotta del bandito. figure 4. an example of morphotype “a” in p4 of the cave bears from the grotta del bandito. figure 5. relationship between the morphodynamic factor of morphotype and upper/lower fourth premolars (p4/p4) length from grotta del bandito, adjovska jama, schwabenreith and gamssulzen caves (partly modified after: rabeder, 2011). g eologia c roatica santi and rossi: ursus gr. spelaeus from grotta del bandito (piedmont, northern italy). 1. morphodynamics of teeth and indications ... 5 firmed in the future by the distribution of frequencies, it raises the possibility that at least two populations of bears (of different ages?) lived in the bandito cave. fourth upper/lower premolars (p4/p4). figure 3. shows the distribution of the frequency of the morphotypes in the upper and lower fourth premolars. considering also the analysis undertaken by zunino & pavia (2005) for the p4, the frequencies of the morphotypes (sensu rabeder, 1999) are: 1 a/b1, 1 b1, 1 b1/ c1, 1 c1/d1, 16 c1, 4 c2, 8 d1, 3 d2, 1 d3, 1 e1, while for p4 the morphotype frequencies are: 9 a (fig. 4), 12 b, 1 c, 6 a/d, 5 d, 2 e. this distribution (the most frequent being that of the lowest morphotypes) is similar to that obtained for other cave bear popu­ lations in northern italy. in summary, cave bear populations with variable sizes (from medium to large) lived in northern italy, but with very simple premolars; this is evidence that could indicate, a probable inter­ mediate step in the evolutionary tree. in figure 5 we only present the results of our measurements for the upper and lower fourth premolars, as well as the relationship between the morphodyna­ mics and length of p4/p4 of bears from the grotta del bandito and other caves where different species and subspecies were found. differences among the species are not noticed. a surprising view is shown in fig. 6; in fact, the most important caves in italy are placed in an interesting “cloud”. a radiometric date of 29,130±90 yrs, was recently published for the covoli di velo by rossi et al. (2018). in figure 6, in which the morphodynamic index of p4 and p4 are in correlation, the grotta del bandito data are also in­ serted. we recall that the fontana marella and mt. generoso caves are located in western lombardy near the boundary with piedmont. in general, three aspects are noted: 1) both the grotta del bandito and covoli di velo (veneto region) are placed along the “austrian line”, 2) the group composed by the levels fm an mg is substantially placed around the “french line”, 3) the grotta del cerè (veneto region) and the grotta del buco dell’orso (la­ glio, lombardy region) are placed in a position in which the aus­ trian and french lines are not clearly separated. data for laglio (buco dell’orso cave) premolars are too scarce to be able to ad­ vance any considerations. the exception is the s. donà samples positioned along the “french line”. previously we indicated that the morphodynamic indices only give a relative indication of the evolutionary step reached by the bears (robu, 2016). the posi­ tion of the bandito is between the mis 5 (80­130 ky) and mis 4 (fig. 6) and to our surprise we can see that these bears occupy an evolutionary step similar to that of the early “populations” of cave bears. the contradiction between the bears of the younger age and the relative simplicity of their dentition, is confirmed. con­ sequently, we can also hypothesize that italian territories were colonized by populations of bears coming from different areas of europe, a mixed population that maybe separated rather early. are the north italian territories the zones of migration paths from west to east and vice versa? is it possible that only a single phy­ letic line, the austrian one, colonized northern italy and that the table 3. radiometric dating for some italian cave bears (modified after: rossi et al., 2018). # site region radiometric dating k yr bp source 1 conturines trentino alto-adige 107.2-115.8 to 41.9-47.5 (uran series) rabeder et al. (1994) 2 conturines trentino alto-adige 40.19±0.9 döppes et al. (2018) 3 conturines trentino alto-adige >49 döppes et al. (2018) 4 conturines trentino alto adige >50.579 to >46.435 spöttl et al. (2018) 5 grotta generosa lombardy 38.2±1.4 bianchi-demicheli & oppizzi (2001) 6 grotta generosa (level 2) lombardy 39.2±1.0 to 51.2±4.0 bona (2004) 7 grotta generosa (level 4) lombardy 46.7±2.4 bona (2004) 8 grotta generosa (level 6) lombardy 47.8±2.6 to 50.8±5.0 bona (2004) 9 fontana marella (fm1) lombardy 21.81±0.2 perego et al. (2001) 10 fontana marella (fm2) lombardy 22.31±0.2 perego et al. (2001) 11 buse di bernardo trentino alto-adige 25.78±0.22 to 25.1±0.3 avanzini et al. (2000) 12 paina veneto 19.6±0.054 terlato et al. (2018) 13 trene veneto 19.9±0.055 terlato et al. (2018) 14 chiostraccio cave tuscany 24.03±0.1 martini et al. (2014) 15 covoli di velo veneto 29.131±0.9 rossi et al. (2018) figure 6. relationship between the morphodynamic indices of the upper/lower fourth premolars (p4/p4) from grotta del bandito and some caves in italy, france and austria (modified after: quiles, 2004). figure 7. relationship between the morphodynamic indices (std) for the upper/lower fourth premolars (p4/p4) from grotta del bandito and some other caves in italy. g eo lo gi a c ro at ic a geologia croatica 73/16 influence of the “french line” (basura (?) in the liguria region) may have arrived and tried to enlarge it in the last stages of evo­ lution? we need more data to confirm or reject this hypothesis. finally, figure 7 shows that the bandito bears are placed within the “cloud” of the other italian cave bears with the only exceptions of cerè (most ancient deposit) and basura (more ad­ vanced bears) which are separated from the main distribution. in northern italy we have a scarcity of radiometric dating, and only some populations of cave bears have been dated. in table 3 we reported the radiometric data calculated up to the present. first lower molars (m1). considering the morphotypes pro­ posed by grandal d’anglade & lópez­gonzález (2004) (fig. 8), the m1s from the grotta del bandito correspond to those of advanced cave bears; the paraconids are equally sub­ divided in acute and straight and the protoconid from smooth posterior edge to rough posterior edge. metaconids fall between the single with cusplet, to double, while the entoconids are fre­ quently double with cusplets and rarely, single with preceding cusplets (morphotype 13 sensu grandal d’anglade & lópez­gonzález, 2004). finally, the hypoconids exhibit an internal cusplet and hypoconulid. in the bandito bears, teeth with only one metastylid (sensu rabeder, 1999) are the most fre­ quent, although more derived morphotypes (with two or three metastylids) are also present. the entoconid area is composed of cusplets of about the same size, along with another of small size (most frequent) or two (one specimen). regarding the enthypo­ conids only the simpler ones are found; comprising morphotype a (the simple one), a/b (with an enthypoconid but not yet divided from the hypoconid by a furrow) and b (enthypoconid clearly di­ vided from the hypoconid by a furrow). rabeder (2014) studi ed the teeth from križna jama (slovenia) and classified them as u. ingressus; the simplicity of construction of the m1s from bandito prevents their attribution to this species. the dis­ tribution of the main “convergence indices” (sensu grandal figure 8. frequencies (in percent) of the m1 morphotypes from the grotta del bandito. g eologia c roatica santi and rossi: ursus gr. spelaeus from grotta del bandito (piedmont, northern italy). 1. morphodynamics of teeth and indications ... 7 d’anglade & lópez­gonzález, 2004) for the paraco­ nid, trigonid cusplets and the talonid one, are shown in fig. 9; these are rather homogenous, independent of the absolute length of the tooth. also among these teeth a mix of “old” and advance features has also been noted; for example, considering the rela­ tionship between the “total length – talonid breadth” (fig. 10) the point of the bandito bears falls in the field of the “primitive” bears. in contrast, their relationship among the “paraconid con­ vergence index – total length”, the “trigonid convergence index ̶ total length” and the “talonid convergence index-total length” suggests the bandito bears be placed among the “advanced” cave bears. this is a confirmation that in italy cave bears have a mix of features of tooth elements present in the finds of middle and late pleistocene age. second lower molars (m2). metrical data are reported in fig. 11, while the calculated indices are shown in fig. 12. a greater frequency of medium­low indices for the development of the met­ alophids is observed (fig. 12) (on 26 specimens, 11 have a “b” morphotype), whereas in the trigonid construction, the simpler form is lacking. the mesolophid area is characterized by mor­ photypes a (with a central crest and a first formation of a meso­ lophid) and b (with a continuous mesolophid developed as a crest or a line). referring to the enthypoconids area, in the sequence of morphotypes, only the a (without enthypoconids) and the d (subdivision in three main parts) types are lacking. intermediate indices are hence present in the bandito “population”, similar to that for others. generally, a comparison with teeth from other caves shows, as in the bandito specimens, that they have a low morphodynamic index; in the study on the cave bears from križna jama (slovenia), rabeder (2014) calculated for the en­ thypoconid morphotype an index of 181.82 (std 98.12) from 11 specimens, and for the teeth from risovača (late pleistocene, serbia; cvetković & dimitrijević, 2014)) the index is 181.3 (std 97.8). also for the bears from loutrá aridéas (greece) the enthypoconid index is 144.67 (std 78.08) (tsoukala et al., 2006). furthermore, the “palaeopopulation” from ajdovska jama (slovenia) shows a very high morphodynamic index for the enthypoconid (std 166.03) that rabeder (2011) considers at­ tributable to u. s. ladinicus, but in a followed control, the value of 166.03, (tab. 7 in rabeder 2011) is a mistake. in fact, rabeder (2011: p. 36) quoted: “the enthypoconid-index is as­ tonishingly high and even supersedes the gamssulzen population by more than 17%)”. there is a mistakenly given standard value of 133 (instead of 185.3) so the correct standardized value is 117.4, which corresponds to the statement in the text (more than 17%, not more than 66%)”. here, considering the 28 elements in the specimens, it is difficult to distinguish these two species u. ingressus and/or u. s. ladinicus at the species or subspecies level for the bandito bears. third lower molars (m3). a scarcity of specimens does not enable definite conclusions to be drawn, but observing the data the cave bears from the bandito cave have index values that are not completely low or high. the low number of specimens pre­ vent further discussion as the sample is too small. first and second upper molars (m1 ̶ m2). also for these teeth (m1s) the morphodynamic indices (14 specimens and re­ lated to the paracone) are low (index is 75, std is 39.89); this is important because it confirms that for the cave bears in italy, m1s were simple and that in the evolutionary position they occupied an intermediate place. the other morphodynamic indices are de­ fined for the metacone (14 in specimens, index is 110.71, std is 62.90) and the proto?/metacone (14 specimens, index is 135.71, std is 43.43). considering the main components of the tooth, the morpho­ dynamic indices most frequently have an intermediate range; in general the indices for the bandito m2s are low when compared with those from the other caves, aligning them with the other an­ alysed teeth. in conclusion we propose in fig. 13 a summary of the mor­ phodynamics of the teeth from the bandito cave compared with other species of bears (rabeder et al., 2005). in fact, the pre­ molars of the bandito cave fall inside the cloud formed by u. spelaeus, u. s. eremus and u. s. ladinicus; with only u. ingressus being well separated from the cloud (fig. 13a). with these mor­ phodynamic indices, it is difficult to subdivide the different spe­ cies with the exclusion of ingressus, and consequently in our opinion it is better to indicate this distribution (with the bandito bears) as gr. spelaeus. the same consideration can be advanced observing the fig. 13b. the separation of the different species, however, is greater compared to that of the fig. 13a, as well as the third one. having utilised different indices for the different kind of teeth it remains uncertain whether the bandito bears be­ long to one species or another. figure 9. relationship between the main “convergence index” and “length” of the first lower molars (m1) from grotta del bandito. g eo lo gi a c ro at ic a geologia croatica 73/18 figure 10. position of the first lower molars (m1) from the grotta del bandito (red point) utilizing the relationships between the main convergence indices and “length”. iberian peninsula: e: eirós; c: a ceza; l: liñares; ar: arrikrutz; tr: troskaeta; ek: ekain; to: toll; re: reguerillo; cm: atapuerca (cueva major); british islands: ba: bacton; we: westbury; central europe: ei: einhornhöhle (scharzfeld); ru: rubeland; ga: gailenreuther (zoolithenhöhle); hu: hundsheim; ni: nixloch; li: lieglloch; cu: conturines; eastern europe: lo: loutraki (greece); od: odessa (ukraina) (modified after: grandal d’anglade & lópez-gonzález, 2004). figure 11. parameters (modified after: tosukala & grandal d’anglade, 1997) and metrical data of the m2 from grotta del bandito. g eologia c roatica santi and rossi: ursus gr. spelaeus from grotta del bandito (piedmont, northern italy). 1. morphodynamics of teeth and indications ... 9 figure 12. frequencies, values and standardized values of the morphodynamic indices of the metalophid (1), mesolophid (2) and enthypoconid (3) of m2 from grotta del bandito. figure 13. morphodynamics of the teeth from grotta del bandito compared with the other cave bears species (modified after: rabeder et al., 2005). g eo lo gi a c ro at ic a geologia croatica 73/110 figure 14. a. relationship between the p4/p4 index (std) from grotta del bandito and some caves in which different taxa of ursus have been found and the altitude of the cave entrance. b. relationship between the m2 metaloph index (std) from grotta del bandito and some caves in which different taxa of ursus have been found and the altitude of the cave entrance. c. relationship between the m2 enthypoconid index (std) from grotta del bandito and some caves in which different taxa of ursus have been found and the altitude of the cave entrance d. relationship between the length of m2 (std) from grotta del bandito and the caves entrance in which different taxa of ursus have been found, and the altitude of the caves entrance (all diagrams modified after: rabeder et al., 2005). e. relationship between the upper/lower fourth premolars (p4/p4) indices and the the cave entrances altitudes of the italian and austrian sites (modified after: fassl & rabeder, 2015). g eologia c roatica santi and rossi: ursus gr. spelaeus from grotta del bandito (piedmont, northern italy). 1. morphodynamics of teeth and indications ... 11 5. morphodynamics-altitude relationship a relationship between the altitude of the cave and the morpho­ dynamics of the teeth has often been searched for in the past (rabeder et al., 2005; laughlan, 2012). here we inves­ tigate whether there is any possible relationship between the al­ titude and teeth (morphodynamic and morphometry) from the bandito cave. fig. 14a­e shows the relationship between the premolar and molar indices and the altitude of the cave; the data of the bandito bears falls in between the spelaeus eremus and ingressus taxa. moreover, a hypothetical relationship between the m2 size and the altitude of the cave is also shown (fig. 14 d); there is not an equal position of the bandito bears; in fact in the fig. 14a the mark is placed next to some of those belonging to s. eremus and s. ladinicus, while in the second one the bandito bears are approximated to ingressus. the picture is confused and a relationship between the size of the tooth and the altitude of the cave cannot be demonstrated. the same considerations could be proposed when considering the enthypoconid of m2s and the to­ tal length of these teeth. on the basis of these data, a relationship between the distribution of the different species of cave bears and altitude also does not exist. concerning the bandito bears another consideration can be postulated. it is very difficult to determine which species of cave bear inhabited this area of piedmont dur­ ing the late pleistocene. finally, a relationship between the p4/ p4 index and the altitude of the cave entrances referred to ursus ingressus only, is also shown (fig. 14e). independently of the taxon considered (u. ingressus), the position of the bandito point is interesting because it opens a discussion about the “migration path” and consequently about the colonization of the cave bears and also perhaps some phyletic considerations. in fact, the ban­ dito is placed at the beginning of the distribution of the “alpin­ gruppe” (sensu fassl & rabeder, 2015) nearly on the same altitude where the arzberg cave is placed (the latter is included in their “colline gruppe” by fassl & rabeder, 2015). the distribution of the italian localities is unexpected. from a com­ mon beginning, the lineage direction is very different to that of other bears. is it true that the italian cave bears are effectively a “separate” assemblage from others in europe? many signs would seem to confirm this (size, a low or medium morphodynamic in­ dex of the teeth, both the plumpness indices and the k­i for the metapodia are similar to those of other european “populations” etc.). further studies are necessary to solve this dilemma. 6. is ursus spelaeus the single species that lived in italy? often in the past we have supported the thesis of the presence of a single species ursus spelaeus in northern italy (e.g. santi & rossi, 2014). previous studies on fossils from different caves of northern italy have shown a strong homogeneity among the ita­ lian “populations”. the grotta del cerè (verona, veneto) is the exception, where in fact, among the fossiliferous material, re­ mains of u. deningeri von reichenau, 1904 and u. arctos linnaeus, 1758 together with u. spelaeus have been found (rossi & santi, 2005). in their research on the metapodia from selected caves of italy, santi & rossi (2014) have shown that morphometrically ursus spelaeus rosenmüller, 1794 is the single species that lived in the italian alps. the differences in size are probably a result of population variability and no clear evidence of other spelaeoid species and/or subspecies, i.e. ingressus, s. ladinicus and s. eremus, has been discovered. a relation­ ship between the size and the altitude of the cave is absent. in italy therefore up to now, chronological data and mtdna analy­ ses are lacking, a complete study, that includes the morphometry, morphodynamics, chronology and genetics, is missing. until now, only the basura assemblage (liguria region) seems to be very different from the other cave bears in northern italy; in fact, the morphodynamic indices of the fourth premolars are higher compared with those of other italian cave bears (quiles, 2004; santi & rossi, 2014). for this assemblage a possible higher step in the evolutionary scale could be hypothesized. contrary to the basura population, in the pocala cave (friuli venezia giulia, eastern italy), the cave bears have a large size, but the fourth pre­ molars has a very simple structure (rossi & santi, 2015). consequently, a confused picture on the morphodynamic indices is highlighted with the highest value (basura) and the lowest ones for the grotta delle fate assemblage (liguria). two different ex­ planations could be proposed: either this represents the presence of more taxa of ursus, or an intraspecific variability of a single species. the discussion is, at the present time still open. 7. conclusions the study of the teeth of the cave bear from the grotta del ban­ dito (piedmont, northern italy) leads to the following conclu­ sions. the teeth are generally of medium ­size, although in some cases large specimens are also present; they are similar to other taxa of cave bears (ingressus, s. eremus, s. ladinicus). with these morphometric results the studied bears are determined as cave bears, but for the bandito sample and the italian cave bears in general it is not easy to distinguish which species they belonged to. the bandito bears show the features of different “species”; in some cases these elements appear to be “primitive”, in others they are more evolved. to indicate a dominant taxon is difficult, be­ cause the taxonomic determination sensu rabeder et al. (2004) is mostly based on genetics, not on morphometrics. we prefer to indicate the bandito cave bears as gr. spelaeus, not a single species, and no relationship with the altitude of the cave is noted. from a general point of view, these bears occupied probably, an intermediate evolutionary step, and therefore more evolved individuals are also present. in fact, in the fourth premolars, zu­ nino & pavia (2005) found higher morphotypes than in the other “italian” “populations“ in which these are absent. the ex­ planation is not clear, but the closeness of the basura cave (lig­ uria region) in which more advanced bears are found (quiles, 2004) can suggest postulation of for example, the hypothesis of the replacement of the “primitive” bears with “advanced” ones. if in the basura cave the disappearance of the primitive bears seems clearer, in the bandito cave it is less clear. in other words, during the late pleistocene, close to the cave bears extinction (in fact the assemblage of the bandito cave and that of fontana marella are very similar), two different “populations” probably cohabited for a short period in the bandito cave area, one of these composed of “primitive” bears and a second, formed of a few, but more evolved specimens. therefore, the complete substitution did not occur at once because the cave bears vanished and became extinct. the problem is still open. acknowledgement the authors thank dr. alessandro garassino (milan) and dr. giorgio teruzzi (milan) for access to the museo civico di storia naturale of milan collections, three anonymous reviewers, the guest editor that with their comments improved this work, and dr. nicki b. charles­star (cleveland) for the revision of the english language. g eo lo gi a c ro at ic a geologia croatica 73/112 references avanzini, m., bertolini, m., betti, g., borsato, a., calmieri, g., del­ lantonio, e., lazinger, m. & zambotto, p. (2000): resti di ursus spelaeus dalle “buse di bernardo” e dal “covelo di rio malo” (trentino-italia): alcune implicazioni paleo ambientali.– studi trentini di scienze naturali ­ acta geologica, 75(1998), 155–160. baryshnikov, g., gimranov, d. & kosintsev, p. (2018): variability of the upper incisors in the cave bears (carnivora, ursidae) from the caucasus and urals.– comptes rendus palevol, 18, 209–222. doi: 10.1016/j.crpv.2018.08.001. bianchi-demicheli, f. & oppizzi, n. (2001): ricerche speleologiche e paleon­ tologiche nella regione del monte generoso: la caverna generosa.– bolletino del­ la società ticinese di scienze naturali, 89, 61–66. bona, f. (2004): preliminary analysis on ursus spelaeus rosenmüller et heinroth, 1794 populations from „caverna generosa“ (lombardy–italy).– cahiers scientifique du muséum d’histoire naturelle de lyon hors série, 2, 87–98. cvetković, n.j. & dimitrijević, v.m. (2014): cave bears (carnivora, ursidae) from the middle and late pleistocene of serbia: a revision.– quaternary internati­ onal, 339–340, 197–208. doi: 10.1016/j.quaint.2013.10.045 döppes, d., rabeder, g., frischauf, c., kavcik­graumann, n., kro­ mer, b., lindauer, s., friedrich, r. & rosendahl, w. (2018): ex­ tinction pattern of alpine cave bears­new data and climatological interpretation.– historical biology. doi: 10.1080/08912963.2018.1487422. fassl, s. & rabeder. g. (2015): die höhlenbären der arzberghöhle (1741/4) bei wildalpen ­ neue daten und forschungsergebnisse von ursus ingressus. vho – verein für höhlenkunde in obersteier, 248–254. frischauf, c. (2014): the cave bear incisors from križna jama (slovenia).– mittei­ lungen der kommission für quartärforschung der österreichischen akademie der wissenschaften, 21, 75–83. frischauf, c., liedl, m.p. & rabeder, g. (2014): revision der fossilen bären der drachenhöhle (mixnitz, stmk).– die höhle, 65/(1–4), 47–55. grandal d’anglande, a. & lópez­gonzález, f. (2004): a study of the evolution of the pleistocene cave bear by a morphometric analysis of the lower car­ nassial.– oryctos, 5, 83–94. laughlan, l. (2012): metrik und evolutionsniveau der höhlenbärenzähne aus der medvedia­höhle im slovenský raj (slowakei).– diplomarbeit angestrebter akademischer gradmagistra der naturwissenschaften (mag.rer.nat.) (unpublished) universität wien, 96 p. lubine, v.p., tcherniachovski, a.g., baryshnikov, g.f., levkovs­ kaia, g.m. & selivanova, n.b. (1985): la grotte de koudaro q1 (resultants de recherches pluridisciplinaires).– l’anthropologie, 89/2, 159–180. martini, i., coltorti, m., mazza, p.p.a., rustioni, m. & sandrelli, f. (2014): the latest ursus spelaeus in italy, a new contribution to the extinction chro­ nology of the cave bear.– quaternary research, 81, 117–124. doi: 10.1016/j. yqres.2013.10.003. orlando, l., bonjean, d., bocherens, h., thenot, a., argant, a., otte, m. & hänni, c. (2002): ancient dna and the population genetics of cave bears (ursus spelaeus) through space and time.– molecular biology and evolution, 19/11, 1920–1933. doi: 10.1093/oxfordjournals.molbev.a004016 perego, c., zanalda, e. & tintori, a. (2001): ursus spelaeus from grotta sopra fontana marella, campo dei fiori massif (varese, italy): morphometry and paleoecology.– rivista italiana di paleontologia e stratigrafia, 107/3, 451–462. quiles, j. (2004): analyse morphodynamique de l’ours des caverne (carnivora, ursi­ dae) de cinq sites du pourtour méditerranéen.– cahiers scientifique du muséum d’histoire naturelle de lyon hors série, 2, 149–161. rabeder, g. (1981): die arvicoliden (rodentia, mammalia) aus dem pliozan und dem alteren plieistozan von niederösterreich.– beiträge zur paläontologie österreichs, 8, 1–373. rabeder, g. (1991): die höhlenbären der conturines – entdeckung und erforschung einer dolomiten­höhle in 2800 m höhe. 124 p. verlagsanstalt athesia­bozen. rabeder, g. (1999): die evolution des höhlenbärengebisses. mitteilungen der kom­ mission für quartärforschung der österreichischen akademie der wissenschaften, 11, 1–102. rabeder, g. (2011): metrical analysis and evolutionary level of the cave bear teeth from ajdovska jama.– mitteilungen der kommission für quartärforschung der ös­ terreichischen akademie der wissenschaften, 20, 31–42. rabeder, g. (2014): metrics and evolutionary level of teeth of the bears from križna jama (slovenia).– mitteilungen der kommission für quartärforschung der öster­ reichischen akademie der wissenschaften, 21, 57–63. doi: 10.2307/j.ctv8mdn09.12 rabeder, g. & tsoukala, e. (1990): morphometric analysis of some cave-bear teeth from petralona (chalkidiki, north greece).– beiträge zur paläontologie österreichs, 16, 103–109. rabeder, g., hofreiter, m., nagel, d. & withalm, g. (2004): new taxa of alpine cave bears (ursidae, carnivora).– cahiers scientifique du muséum d’histoire naturelle de lyon hors série, 2, 49–67. rabeder, g., steffan, i. & wild, e. (1994): the chronological position of the cave bears from conturines cave: abstract, 2nd international cave bears sympo­ sium alta badia. rabeder, g., hofreiter, m. & wild, e.m. (2005): die bären der brieglers­ berghöhle (1625/24).– die höhle, 56/1–4, 36–43. robu, m. (2016): age re-assessment of the cave bear assemblage from urşilor cave, north­western romania.– international journal of speleology, 45/2, 123–133. doi: 10.5038/1827­806x.45.2.1947. rossi, m. & santi, g. (2005): first morphometric data about the metapodial bones of ursus from cerè cave (venetia region, north italy).– cranium, 22/2, 13–25. rossi, m. & santi, g. (2007): differentiation between ursus deningeri von reichenau and ursus spelaeus rosenmüller based on mandibles from caves of the veneto re­ gion (northern italy). an overview.– grzybowski foundation special pubblication, 12, 73–78. rossi, m. & santi, g. (2011): ursus deningeri-spelaeus group from cerè cave (vene­ to, north italy) in the new evolutionary frame of the cave bear. part one: skulls and mandibles.– annales naturhistorische museum wien, serie a, 113, 567–590. rossi, m. & santi, g. (2012): morphometric and morphodynamic data on the man­ dibula and dental fossils of ursus spelaeus rosenmüller, 1794 from “pale rosse” cave (passo brocon, trentino alto adige, northern italy).– studi trentini di scien­ ze naturali, 92, 55–61. rossi, m. & santi, g. (2013): studio morfometrico e morfodinamico di resti crania­ li, dentali e mandibolari di ursus spelaeus dalla grotta del buco del frate e dall’al­ topiano di cariadeghe (brescia) nel quadro evolutivo degli orsi delle caverne.– na­ tura bresciana, annali del museo civico di storia naturale brescia, 38, 33–43. rossi, m. & santi, g. (2015): observations on the ursus gr. spelaeus remains from the pocala cave (trieste, friuli venezia giulia, n. italy).– revue de paléobiologie genève, 34/1, 77–84. rossi, m., zorzin, r. & santi, g. (2006): morphometric observations about the ursus fossils from cerè cave (venetia region, n. italy).– bulletin de la société d’histoire naturelle de toulouse et de midi­pyrenees, 141/1, 47–49. rossi, m., santi, g., zorzin, r., döppes, d., friedrich, r., lindauer, s. & rosendahl, w. (2018): the first directly dated cave bear from the co­ voli di velo cave (verona province, veneto, northern italy) with some discussion of italian cave bears.– journal of cave and karst studies, 80/3, 145–152. doi: 10.4311/2017pa0111. santi, g. & rossi, m. (2007): new evidences from the bears of the veneto region (northern italy) in the evolutionary picture of the italian cave bears.– scientific an­ nals, school of geology aristotle university of thessaloniki (auth), special vol­ ume, 98, 179–186. santi, g. & rossi, m. (2008): fossili craniali e mandibolari di ursus da grotte del veneto (italia settentrionale) nuove osservazioni sul quadro evolutivo degli orsi italiani.– atti del museo civico di storia naturale di trieste, suppl., 53, 3–12. santi, g. & rossi, m. (2014): metapodial bones of ursus gr. spelaeus from selected caves of the north italy. a biometrical study and evolutionary trend.– annales de paléontologie, 100, 237–256. doi: 10.1016/j.annpal.2014.01.003. santi, g. & rossi, m. (2018): evolutionary level of the cave bear from the grotta del bandito (piedmont, n. italy).– slovenský kras­acta carsologica slovaca, 56/1, 5–14. santi, g., rossi, m. & fonte, a. (2005): morphometry of the limb bones of the ursus spelaeus rosenmüller-heinroth, 1784 from delle streghe cave (sambughet­ to valstrona, piedmont–northern italy).– revue de paléobiologie genève, 24/2, 597–616. spötl, c., reimer, p.j., rabeder, g. & bronk-ramsey, c. (2018): radio­ carbon constraints on the age of the world’s highest­elevation cave­bear population, conturines cave (dolomites, northern italy).– radiocarbon, 60, no 1, 299–307. doi: 10.1017/rdc.2017.60. terlato, g., romandini, m., nannini, n., peresani, m. & bocherens, h. (2017): cave bear (ursus spelaeus) extinction in northeastern italy: anthropic impact, stable isotope evidence and extinction chronology.– aragonit, 22/1, 26. terlato, g., bocherens, h., romandini, m., nannini, n., hobso­ nand, k.a. & peresani, m. (2018): chronological and isotopic data support a revision for the timing of cave bear extinction in mediterranean europe.– his­ torical biology, 1–11. doi: 10.1080/08912963.2018.1448395. tsoukala, e. & grandal d’anglade, a. (1997): système de mesures sur le squelette d’ursidae. université pierre mendès france de grenoble/southern me­ thodist university – symposium d’auberives­en­royans­isère­france, 4­6 no­ vembre 1997, l’ours et l’homme, 265 ̶ 287. tsoukala, e., chatzopoulou, k., rabeder, g., pappa, s., nagel, d. & withalm, g. (2006): paleontological and stratigraphical research in loutrá aridéas bear cave (almopia speleopark, pella, macedonia, greece).– scientific annals, school of geology aristotle university of thessaloniki (auth), special volume, 98, 41–67. zunino, m. & pavia, g. (2005): il deposito a ursus spelaeus della grotta del ban­ dito (roaschia, cuneo, italia): considerazioni stratigrafiche, tafonomiche e biocro­ nologiche.– rendiconti della società paleontologica italiana, 2, 243–254. 2022 | 75/1 | 165–176 | 4 figs. | 2 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction in ancient times, iron was one of the most valuable materials, and whole cultures relied upon iron production that was utilised to create an array of different objects. the main method for production of iron in pre-industrial times was the smelting of iron ores via a direct reduction process, in order to obtain an iron bloom. the metallurgical principle in this method relies on the chemical reduction of iron oxide(s) and oxyhydroxide(s) present in the iron ore by carbon or gases formed during smelting (pleiner, 2000). during the smelting process, carbon monoxide (co) from charcoal reacts with iron oxide(s)/oxyhydroxide(s) from the ore, forming iron particles and carbon dioxide (co2) (charlton et al., 2010). air could have been blown into a furnace through blowing holes/tuyeres incorporated in the furnace walls to elevate the temperature and improve the bloom formation. additional material in the form of fluxes could have been added during the process to enhance iron gain and to lower melting temperatures (charlton et al., 2012). compounds such as silica, aluminium and unreduced iron partition from the iron as a liquid phase solidifying at the bottom of the furnace, forming furnace bottom slag (fbs) or they are discharged from the furnace, forming tap slag (ts) (portillo-blanco et al., 2020). textural characteristics of slag are depended on the cooling conditions, while the mineralogical and geochemical composition of smelting slags depends on the raw material used (ore, charcoal, furnace walls), potential use of flux materials (carbonates) and the way the process was carried out (air input, ratio of ore:charcoal etc.). in the study area of the podravina region, several sites with traces of iron production and processing were excavated (sekelj ivančan & karavidović, 2021) while over 150 potential sites were identified through field surveys (valent, 2021). bog iron ores were also detected on some sites within an archaeological context and during surface field surveys (brenko et al., 2021), implying that they were potentially utilised for iron production. iron ores, and especially bog iron ores (kaczorek & sommer, 2003), are never formed purely from iron oxides/oxy the contribution of geochemical and mineralogical characterization of iron slags in provenance studies in the podravina region, ne croatia tomislav brenko1,*, tena karavidović2, sibila borojević šoštarić1 and tajana sekelj ivančan2 1 university of zagreb, faculty of mining, geology and petroleum engineering, department of mineralogy, petrology and mineral resources, pierottijeva 6, 10 000 zagreb, croatia; (*corresponding author: tomislav.brenko@rgn.unizg.hr) 2 the institute of archaeology, jurjevska ulica 15, 10 000 zagreb, croatia doi: 10.4154/gc.2022.11 abstract archaeological excavations in the podravina region led to discovery of sites with traces of bloomery iron production during late antiquity and the early middle ages. mineralogical analysis of the slags recognized fayalite as the main mineral phase, while geochemical analysis confirmed high fe contents, typical for bloomery iron smelting. based on the previously established occurrences of bog iron ores in the study area, provenance studies were carried out using trace and rare earth elements to create a geochemical signature. similar shapes and patterns of bog iron ores and iron slag signatures imply a genetic connection between the ore and the slag, as well as variation related to the temporal and spatial context of both slags and ores. hydroxides (ramanaidou & wells, 2014), but rather as a combination of iron oxides/oxyhydroxides and aluminosilicate soil phases. the combination of heterogenous iron ore, with the possible addition of flux materials, charcoal and furnace lining during smelting, significantly complicates provenance studies. however, recent studies regarding the usage of major and trace elements (including rare earth elements) indicate the potential for following the geochemical signature from the iron ore to the iron slag (horstmadsen & buchwald, 1999, crew, 2000; coustures et al., 2003; schwab et al., 2006; desaulty et al., 2009). major element analysis is used as a first discriminator of the smelting process using non-reduced compounds (nrc) ratios (dillman & l’héritier, 2007). by comparing major element ratios in iron slags, it is possible to distinguish different ore sources. however, nrc ratios are only useful in limited cases when there are some significant differences among the ore deposit sites. therefore, special attention must be given to the differentiation of elements between the solid and liquid phases during smelting, especially the trace elements. trace elements that prefer to remain in the solid phase (bloom) are termed compatible, while trace elements that go into the liquid phase (slag) are termed incompatible, as they are incompatible in the crystal structure and will try to partition at the first available opportunity, i.e. during smelting when high temperatures are introduced into the system (rollinson, 1993). according to studies undertaken by coustures et al. (2003) and desaulty et al. (2009), it can be deduced that the majority of incompatible elements will pass into the slag during the smelting process. desaulty et al. (2009) concluded that the enrichment factor of incompatible elements is close to their modal factor, meaning that their ratios should remain constant from the ore to the slag. a similar observation was previously made by coustures et al. (2003) where plotting pairs of incompatible elements that have the same number of electrons and an equivalent ionic radius revealed that the incompatible pairs should retain the same ratios between the ore and the slag. despite the fact that the slag can contain traces of iron particles from the bloom, due to their small size and low article history: manuscript received november 15, 2021 revised manuscript accepted january 05, 2022 available online january 31, 2022 keywords: iron production, xrd, icp-ms/aes, trace elements, nrc ratios, pca, bog iron ore g eo lo gi a c ro at ic a 166 geologia croatica 75/1 quantities it can be considered that their effect on the overall trace element content in the slag is negligible. considering these aspects, this paper has two main aims: (i) defining the mineralogical and geochemical characteristics that can lead to determining temporal and spatial variation in tap and furnace bottom slags from three sites dated to the late antiquity and early middle ages and (ii) constructing the geochemical signature of iron slags to compare it to the local bog iron ores. in order to do that, two different slag sample types were analysed using geochemical and mineralogical methods. to establish the provenance of the studied iron slags, the geochemical signature using 26 selected trace elements and rare earth elements (rees) was established for all slag samples. geochemical signatures of slags are compared to the geochemical signatures of previously analysed bog iron ores found in the study area (brenko et al., 2021). 2. geological and archaeological settings the archaeological sites related to iron production from which the slag and ore samples originate are dated to the late antiquity figure 1. a) map of the study area with locations of iron slags and iron ores used in this study. typical morphology of b) tap slags and c) furnace bottom slags in the study area. g eologia c roatica 167brenko et al: the contribution of geochemical and mineralogical characterization of iron slags in provenance studies in the podravina region, ne croatia and early middle ages, from the 4/5th (virje-sušine), 5/6th century (virje-volarski breg), as well as to the end of the 6th and mid7th century (virje-sušine, hlebine-velike hlebine) and to the end of the 8th and the beginning of the 9th centuries (virje-volarski breg). individual sites virje-volarski breg and virje-sušine have several positions, where archaeological trenches were set on the basis of prior geophysical research, through which the area saturated with iron production debris was presumed. on all of the excavated positions traces of bloomery iron production workshops (sekelj ivančan & karavidović, 2021) were discovered. the basic technological solution, in terms of the type of furnace used, was similar on all sites. the furnaces were freestanding, with a shallow hearth from which the slag was tapped out during the smelting procedure. the shaft was built entirely of clay, saturated with sand to some degree. the sites are all located in the central part of the lowland podravina region (croatia), on a linear distance between 0.7–7 km (fig. 1). the most prominent geographical feature in the area is the meandering drava river. surrounding the river is the low-lying terrain of three alluvial river terraces. the river valley formed during the last holocene climatic warming period (head, 2019), where constant floods resulted in the deposition of a variety of flood sediments, including gravels, sands and silts (lóczy et al., 2014). hydrological (brkić et al., 2010; brkić & briški, 2018) and hydrochemical (kopić et al., 2016) studies discovered that the groundwater table is close to the surface, with the aquifer system often showing elevated contents of iron and manganese. the majority of soils in the study area are determined as fluvisols and gleysols (bašić, 2013). the combination of shallow groundwater enriched with iron results in the formation of bog iron ore in the study area (brenko et al., 2021), a sedimentary accumulation of iron and accompanying elements formed in soils due to the precipitation of iron in intervals with higher oxygen concentration (ramanaidou & wells, 2014). 3. materials and methods in this study, 33 iron slag samples (table 1) were selected and analysed. samples can be categorized in two main slag groups: furnace bottom slags (fbs) and tap slags (ts). from each site, table 1. mineral composition of selected tap slags and furnace bottom slags in the podravina region. mineral abbreviations: ank – ankerite; dol – dolomite; fay – fayalite; gth – goethite; hem – hematite; lct – leucite; mag – magnetite; pl – plagioclase; px – pyroxene; spl – spinel; wus – wüstite; 10å/14å clay – phyllosilicates with 001 peaks at 10 or 14å. sample trench / su / sample nr. site age fay qz gth hem mag wüs other minerals h-vh ts 1 1/38b/133 hlebine – velike hlebine 6–7th century +++ – – – + + spl h-vh ts 2 1/37a/1/137 +++ ? – – – + spl, dol (?) h-vh ts 3 1/37a/1/140 +++ ? – – – – spl, dol (?) h-vh ts 4 2/113/266 +++ + + – – ? pl, stishovite (?) h-vh ts 5 2/113/270 +++ + – – – – px (?) h-vh ts 6 2/109-110/251 +++ ? – – – – spl h-vh ts 7 2/109-110/251 +++ ? – – – – spl (?) h-vh ts 8 2/97/98/ +++ + – – – ? / h-vh ts 9 2/65/169 +++ – – – – + spl h-vh fbs 1 1/38a/135 +++ ? ? – – + spl, px (?) h-vh fbs 2 1/37a/144 +++ + – – – ++ / h-vh fbs 3 1/37a/1/137 +++ + – – – – px, 10å clay (?) h-vh fbs 4 1/001/25/36 +++ + – – – + px (?) v-s ts 1 7/327/432 virje – sušine 4–5th century +++ + – – – + spl v-s ts 2 7/327/427-1 +++ + – – – ++ px v-s ts 3 7/314/295-1 +++ ? – – – ++ / v-s ts 4 7/317/305/ +++ + – – – ++ px (?) v-s ts 5 7/314/295-7 +++ ? – – – – / v-s ts 6 7/314/295-14 +++ + – – – + spl (?) v-s fbs 1 5/237/126 ++ + ? – – ++ lct v-s ts 7 5/270/125 6–7th century +++ + – – – – spl (?), pl v-s ts 8 5/217/124 +++ + ? + – – pl, px (?) v-s ts 9 5/240/115 ++ + – – – – px, 10å clay (?) v-vb ts 1 3/191/55 virje – volarski breg 5/6–7th century +++ ? – – – – spl (?) v-vb ts 2 2a/138/140 +++ + ? – – + spl v-vb ts 3 2a/138/140 +++ ? – – – ++ spl v-vb fbs 1 3/201/74 +++ + – – – ++ spl, px (?) v-vb fbs 2 3/201/80 +++ + + – – ++ spl, px (?) v-vb fbs 3 3/187/54 +++ + – – – + spl, lct v-vb fbs 4 3/001/180/56a +++ ? – – – – spl, lct v-vb fbs 5 3/001/180/56b +++ + + – – ++ px (?) v-vb fbs 6 2a/173/51 ++ ? ++ + – ++ ank v-vb fbs 7 1/38/95 8–9th century ++ ++ + – – + pl, 10å / 14å + – relative abundance of minerals based on x-ray diffraction (no quantitative value assigned to +); +++ major component, ++ minor component; + traces; ? – not enough diffraction peaks to fully confirm g eo lo gi a c ro at ic a 168 geologia croatica 75/1 both slag types were selected and analysed (fig. 1b and c). the main objective of sample selection was to take into consideration samples from temporally and spatially different sites, as well as samples of different types of slag generated through the bloomery smelting process in order to compare their composition to local bog iron ores from archaeological and/or geological contexts. in order to acquire a reliable mineralogical and geochemical dataset, a slate from the cross section of each sample was cut using a circular saw. by doing so, homogenization was ensured, and potential sampling of rusted or adhering clayey or sandy materials was avoided. each slate was air-dried at room temperature for several days, removing excess moisture and then homogenized to powder fraction using a vibratory mill for several minutes in a steel grinding set. the mineralogical composition was determined by x-ray powder diffraction (xrd) using a phillips vertical x-ray goniometer (type x‘pert) equipped with cu tube and graphite crystal monochromator. scan settings were 3–70° 2θ, 0.02° step size, 1 second count time per step while generator settings were 40 kv and 35 ma. semi-quantitative mineral identification was conducted using panalytical x’pert highscore software with standardised powder diffraction files (pdf) of the international centre for diffraction data (icdd) (newton square, pa, usa) and by comparing peak shapes and heights with internal standards for quartz, feldspars and clay minerals, while fayalite, wüstite and other fe mineral contents were estimated based on geochemical data. the geochemical composition, including the main oxides, major-, microand rees was determined in msalabs (langley, canada). multielement contents of trace and rees were analysed using inductively coupled plasmamass spectrometry (icp-ms), while 4-acid digestion including hydrochloric, nitric, perchloric and hydrofluoric acids was used for near total digestion. only the most highly resistant minerals could possibly remain not fully dissolved. based on two internal standards, several blanks and duplicates, instrumental precision was between 3–5% and the detection limits for most analysed elements were in the part per million (ppm) or lower bracket. major oxide contents were determined using inductively coupled plasma-atomic emission spectrometry (icp-aes) with lithium borate fusion. loss on ignition (loi) was determined by weight difference after ignition at 1000 °c. this approach using trace elements and rees was undertaken in the provenance studies of iron slags in the podravina region. based on the behaviour of the 26 selected elements, it is believed that the geochemical signature of the discovered iron slags could be traced back to ore used for archaeological iron production in the region. to supress the oddo-harkins effect and to table 2. chemical composition of selected iron slags in the podravina region. all values for major oxides and loi given in mass. %. sample location sio2 tio2 al2o3 fe2o3 mgo mno cao k2o na2o p2o5 loi h-vh ts 1 hlebine velike hlebine 22.52 0.24 4.51 65.36 0.53 0.79 1.09 0.59 0.29 0.67 -5.09 h-vh ts 2 25.16 0.23 4.85 63.15 0.57 0.79 1.63 0.77 0.28 0.59 -5.05 h-vh ts 3 26.51 0.27 5.49 66.40 0.65 0.96 2.24 0.92 0.45 0.66 -5.97 h-vh ts 4 29.84 0.27 5.21 61.13 0.78 2.00 1.99 0.81 0.36 0.83 -1.77 h-vh ts 5 26.30 0.22 4.18 66.46 0.81 1.97 1.84 0.67 0.28 0.81 -4.93 h-vh ts 6 27.36 0.30 6.01 60.45 0.67 1.00 1.45 0.97 0.39 0.77 -5.69 h-vh ts 7 32.57 0.35 6.81 58.85 0.88 1.22 2.51 1.67 0.47 0.68 -4.88 h-vh ts 8 27.63 0.28 5.89 59.60 0.60 1.56 2.49 0.99 0.41 0.78 -5.69 h-vh ts 9 26.80 0.25 5.36 65.15 0.81 1.82 2.32 0.83 0.38 0.96 -6.07 h-vh fbs 1 25.58 0.22 4.61 65.35 0.64 0.85 1.75 0.74 0.28 0.61 -4.96 h-vh fbs 2 22.33 0.21 4.99 62.63 0.53 0.73 2.20 0.97 0.30 0.69 -6.31 h-vh fbs 3 32.57 0.34 6.13 55.47 0.72 0.76 2.00 1.12 0.47 0.62 -3.72 h-vh fbs 4 26.64 0.36 5.10 62.68 0.67 0.45 1.66 1.15 0.51 0.74 -3.14 v-s ts 1 virje sušine 25.20 0.19 4.59 54.43 0.52 0.99 1.25 0.82 0.36 0.88 -6.13 v-s ts 2 29.19 0.29 5.66 63.12 0.72 1.02 3.03 1.07 0.42 0.94 -5.26 v-s ts 3 20.88 0.14 3.74 61.02 0.54 0.64 1.99 0.67 0.29 0.99 -6.35 v-s ts 4 25.91 0.19 4.44 61.29 0.70 0.81 3.05 0.97 0.30 0.78 -5.92 v-s ts 5 35.41 0.38 7.23 58.03 0.72 1.00 1.87 1.28 0.56 0.52 -5.27 v-s ts 6 28.92 0.29 5.72 64.26 0.50 1.09 1.16 0.83 0.47 0.52 -5.77 v-s ts 7 37.28 0.38 7.01 55.98 0.70 1.04 1.47 1.08 0.60 0.58 -4.69 v-s ts 8 34.05 0.38 6.74 56.91 0.93 1.18 3.08 1.08 0.56 0.51 -3.87 v-s ts 9 27.96 0.26 5.45 61.11 0.62 0.92 1.68 0.83 0.44 0.49 -4.28 v-s fbs 1 25.72 0.27 4.59 54.87 0.99 0.53 3.63 2.84 0.34 1.15 -2.08 v-vb ts 1 virje volarski breg 28.57 0.33 7.89 55.80 0.97 1.52 1.86 1.13 0.41 0.66 -5.12 v-vb ts 2 25.90 0.25 7.26 53.46 0.79 1.09 1.90 1.12 0.34 0.93 -4.32 v-vb ts 3 25.67 0.24 6.68 57.60 0.75 1.26 1.98 1.19 0.36 1.03 -5.36 v-vb fbs 1 21.19 0.22 5.95 55.57 0.86 1.06 2.64 0.77 0.27 1.11 -3.35 v-vb fbs 2 18.55 0.16 4.91 53.23 0.54 0.51 1.58 0.68 0.28 0.87 -2.39 v-vb fbs 3 25.20 0.33 8.03 52.30 1.17 1.36 1.90 0.86 0.38 1.24 -0.52 v-vb fbs 4 23.76 0.30 7.89 54.49 1.11 0.59 2.26 1.16 0.32 0.92 -3.03 v-vb fbs 5 14.56 0.12 4.10 61.34 0.51 0.37 1.53 0.61 0.22 0.65 -2.33 v-vb fbs 6 11.69 0.11 4.34 60.06 0.47 0.31 0.76 0.45 0.10 0.59 4.02 v-vb fbs 7 27.96 0.27 5.03 56.49 0.69 1.06 1.77 1.09 0.43 0.73 -1.34 g eologia c roatica 169brenko et al: the contribution of geochemical and mineralogical characterization of iron slags in provenance studies in the podravina region, ne croatia avoid artificial peaks in the geochemical signature of iron slags, the rees and trace elements were normalized to upper continental crust (rudnick & gao, 2003) and then plotted on the appropriate diagrams for each archaeological site. geochemical signatures of bog iron ores are derived from the dataset in brenko et al. (2021), where both unroasted and roasted iron ores were analysed. the analysed ores were found in the same archaeological context as iron slags or on temporally and spatially related sites as well as in their natural geological setting, during an archaeological field survey of the wider area around archaeological sites under study (samples from novigrad podravski). 4. results 4.1. mineralogical and geochemical characteristics of iron slags tap slags (ts) tend to be dark grey in colour with high lustre, and occasional signs of porosity. their upper surface usually contains signs of flow texture due to their previously melted state. furnace bottom slags (fbs) are also greyish in colour, with parts of samples being red. they tend to be slightly concave in shape due to their position at the bottom of the furnace and usually have higher porosity than ts. mineralogically, both ts and fbs samples contain fayalite (fe2sio4) as the main mineral phase. besides fayalite, all samples contain quartz in traces to moderate amounts, while wüstite (feo) also occurs in the majority of samples as either a major or trace component. other minerals, including iron minerals (magnetite, haematite and goethite) as well as pyroxene, spinel (hercynite) and leucite occur in trace amounts (table 1). additionally, slightly elevated background levels, especially noted in the virjevolarski breg site, point to the possible occurrence of amorphous matter, such as the glassy slag matrix. major oxides composition in the slags mainly consists of fe2o3 ranging from 52.30 66.46 mas. % (χ = 59.52 mas. %) and sio2 ranging from 11.69 to 37.28 mas. % (χ = 26.22 mas. %) (table 2). ts and fbs from the hlebine-velike hlebine site have the highest fe2o3 contents, with values between 55.47 66.46 mas. % (χ = 62.95 mas. %, n = 13). this is followed by fe2o3 contents in slags from the virje-sušine positions, where the contents range from 54.34 64.26 mas. % (χ = 59.10 mas. %, n = 10), while slags from the virje-volarski breg positions have the lowest contents, with values between 52.30 61.34 mas. % (χ = 56.03 mas. %, n = 10) (table 2). only al2o3 with values between 3.74 8.03 mas. % (χ = 5.65 mas. %, n = 33) is present in significant quantities at all archaeological sites. contents of cao (0.76 – 3.63 mas. %, χ = 1.99 mas. %), mno (0.31 – 2.00 mas. %, χ = 1.01), k2o (0.45 – 2.84 mas. %, χ = 0.99 mas. %), p2o5 (0.49 – 1.24 mas. %, χ = 0.77 mas. %), mgo (0.47 – 1.17 mas. %, χ = 0.72 mas. %), na2o (0.10 – 0.60 mas. %, χ = 0.37 mas. %) and tio2 (0.11 – 0.38 mas. %, χ = 0.26 mas. %) are mostly present as minor components (table 2). nrc ratios for several major oxides are presented in fig. 2 and compared with geochemical data from several studies from croatia and europe. biplot diagrams revealed a positive linear correlation in the case of the sio2/al2o3 ratio with the virje-volarski breg site standing out due to higher al contents (fig. 2a). sio2/fe2o3 and fe2o3/mno ratios show a grouping of data for all sites (fig. 2b and 2c). principal component analysis of the major oxide composition in iron slags resulted in ten principal components (pcs). the first principal component accounts for 49.20 % of the total variance with the second pc accounting for 18.90 % and the third for 11.47 % of the total variance (fig. 3b, 3c). according to the obtained values in principal components, pc 1 particularly represents sio2, tio2, al2o3, mgo, k2o and na2o, while strongly representing mno and cao. pc 2 particularly represents p2o5, while fe2o3 is only strongly represented by both pc 2 and pc 3. the resulting scatterplot of pc 1 plotted against pc 2 shows relatively scattered cloud datasets for all study sites (fig. 3a), although confidence ellipses show some grouping. samples from hlebine-velike hlebine are grouped together, as all the samples are in relative proximity to one another. samples from the concurrent virje-sušine site are grouped and plotted close to the hlebine-velike hlebine samples. samples of virjevolarski breg dated to the end of the 5th and into the 6th century are plotted distantly from the first two groups and are widely dispersed. the samples from virje-sušine 4-5th century are also widely dispersed and overlap all other datasets. 4.2. geochemical signature of slags based on trace elements in order to define the geochemical signature of the iron slags, 26 trace elements and rees were selected and normalized to the upper continental crust. apart for several incompatible elements, slag samples from the hlebine-velike hlebine site have an almost identical geochemical signature. slight variability can be seen in the total trace and ree contents, however, same characteristic peaks are appearing through all samples. these slag samples are compared with roasted ore samples (brenko et al., 2021) from the same site i.e. the same archaeological context interpreted as an iron production workshop and from a nearby and contemporary hlebine-dedanovice site. for the majority of the ore samples the patterns have similar shapes and peak heights. some differentiation in ore geochemistry is noticeable, mostly the trace element contents (cs-k) (fig. 4a). samples from the virje-sušine site are divided in two groups, based on the 14c age determined for charcoal samples from two spatially separate positions (botić, 2021; trench 5 and 7), both of which can be interpreted as iron production workshops, dated to the end of 4th and into the 5th century (trench 7) and to the end of the 6th and into the ½ 7th century (fig. 4b). these slag samples are compared with samples of natural and roasted bog iron ore found within the archaeological context (trench 7) and geological samples of bog iron ore from a near-by location of novigrad podravski-milakov berek (linear distance 200-300 metres). differentiation can be noted for the same trace elements (cs-k), however the general shape of the signature is similar, with same peaks appearing as in the case of hlebine-velike hlebine (fig. 4b). when comparing these archaeological samples with bog iron ores from novigrad podravski major differences are seen in both the trace and rees of the ores, such as eu and sm positive anomalies and a strong enrichment of ba (fig. 4b). the virje-volarski breg site is also divided into two groups based on two positions (trench 2a and 3, trench 1) where traces of differently dated iron production workshops were found (5/6thcentury and 8th/9th century). the ores used for provenance were discovered in an archaeological context within settlement features (trench 2b) that can be dated relatively to 8/9th centuries and are spatially connected to both positions (linear distance 45– 251 metres). geochemical signatures of the ores and slags showed a great resemblance. very small differentiation is present for ba contents between the ore and slag, while other elements have the same peaks and peak heights (fig. 4c). g eo lo gi a c ro at ic a 170 geologia croatica 75/1 figure 2. nrc ratios of slag for a) sio2/al2o3, b) fe2o3/sio2 and c) fe2o3/mno compared to other case studies in croatia and europe (according to heimann et al., 2001; coustures et al., 2003; selskiene, 2007; thelemann et al., 2017 and nemet et al., 2018). g eologia c roatica 171brenko et al: the contribution of geochemical and mineralogical characterization of iron slags in provenance studies in the podravina region, ne croatia 5. discussion 5.1. temporal and spatial differences in ore and slag characteristics the mineralogical and geochemical composition of the ore, especially the gangue minerals associated with the iron minerals, has a predominant contribution to the mineralogical and geochemical composition of the resulting slags (portilloblanco et al., 2020). fayalite in the slag was formed as the product of the thermal reaction between fe minerals in the ore (goethite in bog iron ores, haematite in roasted bog iron ores) and quartz during the smelting process, forming the compound fe2sio4 that upon solidification formed olivine phase fayalite (charlton et al., 2012). studies suggest that the formation temperatures for this process were somewhere between 1100 and 1400 °c (pollard & heron, 1996). wüstite is a situationally occurring mineral in iron slags, mostly occurring in slags from the virje sites. it is formed when iron oxide occurs in excess amounts (gordon, 1997), with some studies suggesting that the crystallization starts to occur when the fe/sio2 ratio exceeds 1.5 (kongoli & yazawa, 2001; kądziołka et al., 2020). occurrence of magnetite in some tap slags indicates incomplete reduction during the process, or a secondary formation of magnetite due to the supply of excess air in the smelting system (manasse & mellini, 2002). traces of goethite and haematite can be associated with oxidising conditions (morton & windgroove, 1969) to which the slags would be exposed affigure 3. a) pca scatterplot of pc 1 and pc 2 of the major oxide concentrations, b) principal component loading and eigenvalues and c) eigenvalues of covariance matrix plot. g eo lo gi a c ro at ic a 172 geologia croatica 75/1 figure 4. geochemical signature of iron slags from a) hlebine-velike hlebine, b) virje-sušine and c) virje-volarski breg compared to discovered bog iron ores and roasted iron ores from same or nearby study sites. g eologia c roatica 173brenko et al: the contribution of geochemical and mineralogical characterization of iron slags in provenance studies in the podravina region, ne croatia ter being removed out of the furnace or through the post-depositional changes, influenced by oxidising conditions and humid soil layers. xrd analysis also revealed the occurrence of an al-spinel phase (hercynite) in the smelting slags from all sites, with most occurrences from the virje-volarski breg positions. the presence of hercynite indicates that the used ores had elevated contents of aluminium, possibly from al-phases such as clay minerals and plagioclase. this is in line with previous studies of bog iron ores in the study area (brenko et al., 2021), where mineralogical analysis pointed to the occurrence of soil minerals such as clays and feldspars/plagioclase. the sum of iron, silica and aluminium contents in all locations is mostly around 85 – 90 mass. %, clearly indicating that all samples are metallurgical slags produced during the bloomery iron-making process (bani-hani et al., 2012). the geochemical composition of the slag samples shows similarity to other available study cases from europe (fig. 2). it is worth noting that chemical data of iron slags in this study is similar to data obtained by nemet et al. (2019) for slag samples from the neighbouring turopolje region, especially in regard to mno contents, indicating overall similar chemical conditions in the wider area. upon closer inspection of the major oxide ratios, the regularity and behaviour of major oxides for each site can be detected. studies (blakelock et al., 2009; charlton et al., 2012) suggest that certain oxide ratios remain similar between the ore and the slag and could be used to distinguish the usage of different ores between different sites. previous research regarding possible ore sources for iron production in the podravina region (brenko et al., 2021) indicated higher aluminium contents in bog iron ores from sites within the virje area (sušine and volarski breg) when compared to the hlebine area (velike hlebine and dedanovice). based on the geochemical data, it is highly likely that in each workshop locally available ore from different, probably nearby deposit(s) was used. iron ore used in the hlebine-velike hlebine site probably contained a lower quantity of gangue minerals (clay minerals and feldspars), therefore having lower al contents. it is also possible that the ore was pre-processed by washing or that the ore was carefully chosen, while avoiding clayey ore lumps, as was proposed by brenko et al. (2021) based on the ree contents. on the other hand, some of the ore used at the virjevolarski breg site, both from the workshop dated to 8/9th and to the 5/6th centuries, was probably slightly enriched with gangue minerals, which led to an increase of al in some slags from these positions. increase in al content might be a micro-regional feature typical for the virje area, although this is not entirely supported by the composition of all slag samples from the workshop dated to 4/5th centuries at the virje-sušine site. however, archaeological evidence strongly suggests that separation of the ore was carried out at this site as several samples of roasted bog iron ore were found in a waste discarding area (brenko et al., 2021) so it could be presumed that the ore was more thoroughly pre-processed and/or more carefully selected. another option could be that the ores used for individual smelting procedures were not all of the same microregional origin as at the other positions in the virje area. this study revealed that the discovered iron ores from the virje-sušine and virje-volarski breg sites tend to have increased mn contents with values sometimes reaching over 20 mass. %. however, as shown in table 2, analysed iron slags have low mn contents, with values around 1 mass. %. such low mn contents imply that ore was processed for both manganese and for clay minerals. however, as some mn can still be incorporated into the iron bloom (albeit on rare occasions) (navasitis & selskienė, 2007), further investigation into iron bloom geochemistry could reveal whether the ore was truly pre-processed for mn as well. this could also mean that bog iron ores of different composition were used within a single workshop. the latter would be in line with general bog iron ore characteristics, that can be of very variable quality and overall composition, even if found within the same deposit, and more so in relation to different microenvironmental conditions under which they were formed i.e. different deposits within the same region. a sign of inconsistency of overall characteristics of used ore or the way that the ore was smelted can be seen in the wide dispersion of slag samples from the late antiquity, the virje-sušine workshop (4/5th centries) as well as from the workshop on the virje-volarski breg site belonging to the end of 5/6th century (fig. 3). 5.2. provenance studies numerous studies have been carried out, in an attempt to establish the relationship between possible iron ore and iron slags (pleiner, 1967; devos et al., 2000; schwab, 2006; blakelock et al., 2009), which is not always unbiased, due to numerous reasons. the ore used in iron smelting accounts for around 77–100 % of the chemical composition of slag, and therefore, slag derives the majority of its bulk composition from ore, with part of the composition depending on the furnace structural ceramics, fuel and flux material (crew, 2000). this can be reflected in the frequency distribution charts of major element nrc ratios. coustures et al. (2003) determined that although clay and charcoal alter the trace element composition of the slag, the variability is so insignificant that the correlation coefficient of the two is acceptable. previous study (brenko et al., 2021) suggested that it is possible to determine the type of used ore by comparing the geochemical signature of rare earth and trace elements between samples of bog iron ore and archaeological samples of roasted bog iron ore. however, the method of clustering and correlation was used on archaeological samples that were exposed to an average temperature between 550 and 600 °c, with a maximum spike in temperature of 1038 °c (karavidović, 2020), where limited mobility was recognized between rare earth and trace elements. as iron slags are formed at temperatures much higher than roasted ores, some degree of mobility and fractionation in trace elements is to be expected, even in the case when considering immobile elements such as rees or trace elements (linthewas & setiawan, 2018). slight differentiation of rare earth and trace element contents can be noticed in all sites when comparing the signature of tap slags and furnace bottom slags. based on the diagrams in fig. 4, it seems that tap slags have slightly higher contents of rees and trace elements than furnace bottom slags which can be explained by the thermodynamic behaviour of the incompatible elements, as they are more likely to separate to a more liquid phase, such as the tap slag. therefore, the type of analysed slag inevitably holds some degree of influence on the overall geochemical signature, at least content related. the ideal case in determining the type of used ore in an archaeological context would be to compare the ore found in the same context as the slag itself, which is rarely possible due to the nature of the archaeological record where used raw materials are often not discovered. however, in the case of the hlebine-velike hlebine, slags could be compared to two archaeological samples of roasted ore from the same site interpreted as an iron production workshop, and four samples of roasted ore from a close-by g eo lo gi a c ro at ic a 174 geologia croatica 75/1 concurrent hlebine-dedanovice site. the total contents of trace and rees between the ore and slag samples differ in favour of the slag that can be attributed to iron depletion from the ore to the slag (desaulty et al., 2009). analysed iron slags have lower fe contents than the ore samples used for provenance (brenko et al., 2021). however, when the same elements are plotted on a multielemental diagram, they exhibit characteristic peaks that could indicate the provenance of the slag material. the first noticeable peak is the high positive enrichment of phosphorus in both ores and slags. studies often indicate that bog iron ores contain significant contents of p2o5 (stoops, 1983; landuydt, 1990; török & thiele, 2013; thelemann et al., 2017). this is a strong indication in the usage of bog iron ores for iron production in the study area. trace elements such as cs, rb, k and u are often observed in variable contents in the soils (maes et al., 1999; gingele & decker, 2007; zaunbrecher et al., 2015; fuller et al., 2015). such behaviour was also detected through soil profiles in the podravina region (brenko et al., 2020). therefore, some variability in the geochemical signatures of bog iron ores formed in such soils, and accompanying slags is to be expected, especially if the soils are subjected to constant redox changes such as in the podravina region due to fluctuation of groundwater. the rees (y-lu) part of the diagram is almost identical in shape and patterns in both ores and slags, indicating a similar genetic origin between them. bog iron ores from the archaeological context of the virjesušine site and ores found in a geological context from a nearby novigrad podravski-milakov berek site are compared with the iron slags from virje-sušine. it can be seen that the geochemical signature of slag samples found in the context of the workshop dated between the end of 4th and the beginning of 5th century, and samples from another workshop dated between the end of the 6th and into 7th century show slight discrepancies to one another. this suggests variety in the ore used, most notably the clay minerals, that could be due to exploitation of different deposits or different ore-processing activities. additionally, the geochemical signature of the compared ores belonging to the same archaeological context, the workshop at virje-sušine dated to 4/5th centuries, also shows pattern variability. a possible explanation for this is found within the archaeological context as all of the ore samples were found in layers of smelting debris, implying that these ores were possibly not meant to be used, due to their inadequate metallurgical characteristics as proposed by brenko et al. (2021). however, a distinctive positive phosphorus peak is again present in both ores and slag, indicating that bog ores were used as the primary ore source. based on the mineralogy of the analysed bog iron ores from the study site and nearby novigrad podravski site, differentiation of the used ores can be achieved by observing their ba and sr contents. previous study (brenko et al., 2021) suggests that ba in the ore correlates well with the mn amorphous phase, while an eu anomaly occurs due to the substitution of eu3+ with ca2+ in the calcite structure (hellebrandt et al., 2017), a mineral that was discovered occurring in the ore samples from that location. this implies that mn-rich ores were most likely not used in the individual smelting episodes represented in selected samples. this anomaly also provides evidence to propose that the composition of bog iron ores from the same regional origin can vary significantly in relation to the location of the deposit and presumably the period when bog iron ore was formed. the clearest situation in terms of provenance can be seen in the virje-volarski breg site. the ore samples were found in features within a settlement context dated to the 8/9th centuries, that is spatially connected to the concurrent iron production workshop from which the analysed slag originates (trench 1). this implies that the ore discovered at this location was used for iron smelting and production on the same site. all three ore samples have an almost identical geochemical signature to the signature of the slags, with all the characteristic peaks as indicated by the average ore and average slag lines on fig. 4c. when compared to the slag samples from the workshop dated to the 5/6th centuries, a similar degree of overlapping geochemical signatures is seen. here, some slag samples show depletion in overall contents while others are of almost identical signature. some differentiation can be noticed in the ba contents, but these can also be attributed to slight variations in the mn contents of the bog iron ore, as previous study (brenko et al., 2021) showed correlation between mn and ba in bog iron ores. 6. conclusion in the study area of the podravina region, iron was produced via the direct process i.e. bloomery smelting in the late antiquity and the early middle ages, as excavated archaeological sites suggest. the analysed slag is divided into two groups based on macroscopic analysis: tap slag and furnace bottom slag. both slag types are characterized by fayalite as the main fe mineral phase. occurrences of other fe minerals, such as wüstite, haematite and magnetite imply some variability in the smelting processes. overall, the major oxide composition of analysed slags suggests differentiation for some nrc ratios, such as slight al2o3 differentiation at the virje-volarski breg site. this is related to a higher clay content in the ores used within the virje-volarski breg workshops but as samples of slag and ores originate from differently dated sites, these characteristics could be connected to the usage of iron ores that were formed under similar micro-environmental conditions, presumably in the surroundings of the virje site. an attempt was made to determine the provenance of iron slags in the podravina region, through the analysis of trace and rare earth elements in both slags and locally discovered ores. methods included normalization and plotting of selected elements, forming geochemical signatures for both ores and slags, that were then further compared and analysed. specific peaks, such as the positive p peak implies the usage of locally discovered bog iron ore as the main raw material. in the case of the virje-volarski breg site, identical shapes and peak heights undeniably point to the usage of bog iron ore as the main raw material. differentiation and inconsistency can be seen in signatures from hlebine-velike hlebine and virje-sušine, most notably in the trace element contents. such differentiation stems from trace elements that are incorporated into clay minerals, such as cs, rb and k, questioning their usability as such in the provenance studies. however, general shape of the signatures points toward bog iron ore usage on hlebine-velike hlebine and virje-sušine sites. differentiation between the potential location of the deposits and/or time when the ores were formed can also be presumed from the ores signature, as the ore samples from the archaeological context of virje-sušine site and the geological context from the nearby novigrad podravski-milakov berek site exhibited a different geochemical signature, most notably in regard to ba content. therefore, study indicates the possibility of discrimination in the usage of ores based on their micro-locational or temporal provenance, by detailed mineralogical analysis followed by geochemical analysis. g eologia c roatica 175brenko et al: the contribution of geochemical and mineralogical characterization of iron slags in provenance studies in the podravina region, ne croatia acknowledgment this work has been fully supported by the croatian science foundation under the project transfer iron production along the drava river in the roman period and the middle ages: creation and transfer of knowledge, technologies and goods (grant no. 5047). we would like to thank our project partners from the institute of archaeology and city museum of koprivnica, whose continuous fieldwork led to archaeological discoveries of iron production culture in the podravina region. we would also like to thank stanko ružičić, phd, whose comments helped improve the quality of this manuscript. dataset statement the data that supports the finding of this study is available from the corresponding author upon reasonable request. references bani-hani, m., abd-allah, r. & el-khouri, l. (2012): archaeometallurgical finds from barsinia, northern jordan: microstructural characterization and conservation treatment.− j. cult. herit., 13, 314–325. doi: 10.1016/j.culher.2011.12.005 bašić, f. (2013): the soils of croatia (1st ed.).− springer science+business media dordrecht. doi: 10.1007/978-94-007-5815-5 blakelock, e., martinón-torres, m., veldhuijzen, h.a. & young, t. (2009): slag inclusions in iron objects and the quest for provenance: an experiment and a case study.− j. archaeol. scie., 36, 1745–1757. doi: 10.1016/j.jas.2009.03.032 botić, k. (2021): absolute dating of virje and hlebine sites.− in: sekelj ivančan, t. & karavidović, t. (eds.): interdisciplinary research into iron metallurgy along the drava river in croatia the transfer project, oxford: archaeopress, 92–100. doi: 10.32028/9781803271026-5 brenko, t., borojević šoštarić, s., karavidović, t., ružičić, s. & sekelj ivančan, t. (2021): geochemical and mineralogical correlations between the bog iron ores and roasted iron ores of the podravina region, croatia.− catena, 204, 105353. doi: 10.1016/j.catena.2021.105353 brenko, t., borojević šoštarić, s., ružičić, s. & sekelj ivančan, t. (2020): evidence for the formation of bog iron ores in the soils of the podravina region, ne croatia: geochemical and mineralogical study.− quatern. int., 536, 13–29. doi: 10.1016/j.quaint.2019.11.033 brkić, ž. & briški, m. (2018): hydrogeology of the western part of the drava basin in croatia.− j. maps., 14, 173–177. doi: 10.1080/17445647.2018.1445043 brkić, ž., larva, o. & urumović, k. (2010): the quantitative status of the groundwater in alluvial aquifers in northern croatia.− geol. croat., 63, 283–298. doi: 10.4154/gc.2010.23 charlton, m.f., crew, p., rehren, th. & shennan, s.j. (2010): explaining the evolution of ironmaking recipes–an example from northwest wales.− j. anthropol. archaeol., 29, 352–367. doi: 10.1016/j.jaa.2010.05.001 charlton, m.f., blakelock, e., martinón-torres, m. & young, t. (2012): investigating the production provenance of iron artifacts with multivariate methods.− j. archaeol. sci., 39, 2280–2293. doi: 10.1016/j.jas.2012.02.037 coustures, m.p., béziat, d. & tollon, f. (2003): the use of trace element analysis of entrapped slag inclusions to establish ore – bar iron links: examples from two gallo-roman iron-making sites in france (les martys, montagne noire, and les ferrys , loire t ) .− archaeometry, 45, 599–613. doi : 10.1046/j.1475-4754.2003.00131.x crew, p. (2000): the influence of clay and charcoal ash on bloomery slags.− in tizzoni, c.c. & tizzoni m. (eds.): iron in the alps: deposits, mines and metallurgy from antiquity to the xvi century, bienno, p. 38–48. desaulty, a-m., dillmann, p., l’héritiera, m., mariet, c., gratuze, b., joron, j-l. & fluzin, p. (2009): does it come from the pays de bray? examination of an origin hypothesis for the ferrous reinforcements used in french medieval churches using major and trace element analyses.− j. archaeol. sci., 36, 2445–2462. doi: 10.1016/j.jas.2009.07.002 devos, w., senn-luder, m., moor, c. & salter, c. (2000): laser ablation inductively coupled plasma mass spectrometry (la-icp-ms) for spatially resolved trace analysis of early-medieval archaeological iron finds.− int. j. anal. chem., 366, 873–880. doi: 10.1007/s002160051588 dillmann, p. & l’héritier, m. (2007): slag inclusion analyses for studying ferrous alloys employed in french medieval buildings: supply of materials and diffusion of smelting processes.– j. archaeol. sci, 34/11, 1810–1823. doi: 10.1016/j. jas.2006.12.022 fuller, a.j., shaw, s., ward, m.b., haigh, s.j., mosselmans, f.w., peacock, c.l. stackhouse, s., dent, a.j., trivedi, d. & burke, i.t. (2015): caesium incorporation and retention in illite interlayers.– appl. clay sci., 108, 128–134. doi: 10.1016/j.clay.2015.02.008 gingele, f.x. & de deckker, p. (2005): clay mineral, geochemical and sr-nd isotopic fingerprinting of sediments in the murray-darling fluvial system, southeast australia.– aust. j. earth scie., 52, 965–974. doi: 10.1080/08120090500302301 gordon, r.b. (1997): process deduced from ironmaking wastes and artefacts.− j. archaeol. sci., 24, 9–18. doi: 10.1006/jasc.1995.0092 head j. m. (2019). formal subdivision of the quaternary system/period: present status and future directions.− quatern. int., 500, 32–51. doi: 10.1016/j.quaint.2019.05.018 heimann, r.b., kreher, u., spazier, i. & wetzel g. (2001): mineralogical and chemical investigations of bloomery slags from prehistoric (8th century bc to 4th century ad) iron production sites in upper and lower lusatia, germany.− archaeometry, 43, 227–252. doi: 10.1111/1475-4754.00016 hellebrandt, s.e., hofmann, s., jordan, n., barkleit, a. & schmidt, m. (2017): incorporation of eu(iii) into calcite under recrystallization conditions.− sci. rep-uk., 6, 33137. doi: 10.1038/srep33137 horst-madsen, l. & buchwald, v.f. (1999): the characterisation and provenancing of ore, slag and iron from the iron age settlement in snorup.− the journal of the historical metallurgy society, 33/2, 57–67. kaczorek, d. & sommer, m. (2003): micromorphology, chemistry and mineralogy of bog iron ores from poland.− catena, 54, 393–402. doi: 10.1016/s03418162(03)00133-4 kądziołka, k., pietranik, a., kierczak, j., potysz, a. & stolarczyk, t. (2020): towards better reconstruction of smelting temperatures: methodological review and the case of historical k-rich cu-slags from the old copper basin, poland.− j. archaeol. sci., 118, 105142. doi: 10.1016/j.jas.2020.105142 karavidović, t. (2020): rekonstrukcija postupka prženja rude: eksperimentalni pristup.− in: vitezović, s., antonović, d. & šarić, k. (eds.):aktuelna interdisciplinarna istraživanja tehnologije u arheologiji jugoistočne europe, zbornik radova prvog skupa sekcije za arheometriju, arheotehnologiju i eksperimentalnu arheologiju srpskog arheološkog društva, [current interdisciplinary technology in archaeology research of south-eastern europe, proceedings from first meeting of archaeometry, archaeotechnology and experimental archaeology of serbian archaeological society], 130–137. kongoli, f. & yazawa, a. (2001): liquidus surface of feo-fe2o3-sio2-cao slag containing al2o3, mgo, and cu2o at intermediate oxygen partial pressures.− metall. mater. trans. b., 32, 583–592. doi: 10.1007/s11663-001-0114-7 kopić, j., loborec, j. & nakić, z. (2016): hydrogeological and hydrogeochemical characteristics of a wider are of the regional well field eastern slavonia – sikirevci.− the mining-geological-petroleum bulletin, 31, 47–66. doi: 10.17794/ rgn.2016.3.4 landuydt, c.j. (1990): micromorphology of iron minerals from bog ores of the belgian campine area.− dev. soil sci., 19, 289–294. doi: 10.1016/s0166-2481(08)70340-4. lintjewas, l. & setiawan, i. (2018): mobility of rare earth element in hydrothermal process and weathering product: a review.− iop conf. series: earth and environmental science, 118. doi: 10.1088/1755-1315/118/1/012076 lóczy, d., dezső, j., czigány, s., gyenizse, p., pirkhoffer, e. & halász, a. (2014): rehabilitation potential of the drava river floodplain in hungary.− in: 2nd international water resources and wetlands. conference paper. manasse, a. & mellini, m. (2002): chemical and textural characterization of medieval slags from the massa marittima smelting sites (tuscany, italy).− j. cult. herit., 3, 187–198. doi: 10.1016/s1296-2074(02)01176-7 maes, e., iserentant, a., herbauts, j. & delvaux, b. (1999): influence of the nature of clay minerals on the fixation of radiocaesium traces in an acid brown earth-podzol weathering sequence.− eur. j. soil sci., 50, 117–125. doi: 10.1046/j.1365-2389.1999.00224.x morton, g. r., & wingrove, j. (1969): constitution of bloomery slags, part 1: roman.− j. iron steel i., 207, 1556–1564. navasaitis, j. & selskienė, a. (2007): metallographic examination of cast iron lump produced in the bloomery iron making process.− mat. sci., 13/2, 167–173. navasaitis, j., selskienė, a. & žaldarys, g. (2010): the study of trace elements in bloomery iron.− mater. sci.+, 16/2, 113–118. nemet, i., rončević, s., bugar, a., zubin ferri, t. & pitarević, l. (2018): classification analysis of archaeological findings from early-iron production (turopolje region, nw croatia) based on multi-analytical profiling.− j. anal. atom. spectrom., 33, 2053–2061. doi: 10.1039/c8ja00202a pleiner, r. (1967): die technologie des schmiedes in der großmährischen kultur.− slovenská archeológia, 15/1, 77–188. pleiner, r. (2000): iron in archaeology. the european bloomery smelters.− archeologický ústav av cr, prague, 400 p. pollard, m. & heron, c. (1996): archaeological chemistry.− royal society of chemistry, cambridge, 456 p. doi: 10.1039/9781847550156 portillo-blanco, h., cruz zuluaga, m., angel ortega, l., alonsoolazabal, a., cepeda-ocampo, j.j. & martinez salcedo, a. (2020): mineralogical characterization of slags from the oiola site (biscay, spain) g eo lo gi a c ro at ic a 176 geologia croatica 75/1 to assess the development in bloomery iron smelting technology from the roman period to the middle ages.− minerals-basel, 10, 321. doi: 10.3390/ min10040321 ramanaidou, e. and wells, m.a. (2014): sedimentary hosted iron ores.− in: holland, h.d. & turekian, k.k. (eds.): treatise on geochemistry 2nd ed., 313–355. elsevier, oxford. doi: 10.1016/b978-0-08-095975-7.01115-3 rollins, h. (1993): using geochemical data (1st ed.).− london, united kingdom, 384 p. rudnick, r.l. & gao, s. (2003): composition of the continental crust.− treatise on geochemistry, 3, 1–64. doi: 10.1016/b0-08-043751-6/03016-4 schwab, r., heger, d., höppner, b. & pernicka, e. (2006): the provenance of iron artefacts from manching: a multi-technique approach.− archaeometry, 48, 433–452. doi: 10.1111/j.1475–4754.2006.00265.x sekelj ivančan, t. & tkalčec, t. (2018): settlement continuity at sušine site near virje (north croatia) throughout the middle ages.− konštatínove listy 11, 35–66. doi: 10.17846/cl.2018.11.2.35-66 sekelj ivančan, t. & karavidović, t. (2021): archaeological record of iron metallurgy along the drava river.− in: sekelj ivančan, t. & karavidović, t. (eds.): interdisciplinary research into iron metallurgy along the drava river in croatia the transfer project, oxford: archaeopress, 43−91. doi: 10.32028/9781803271026-4 selskienė, a. (2007): examination of smelting and smithing slags formed in bloomery iron-making process.− chemija, 18, 22–28. stoops, g. (1983): sem and light microscopic observations of minerals in bog-ores of the belgian campine.− geoderma, 30, 179–186. doi: 10.1016/00167061(83)90065-4. thelemann, m., bebermeier, w., hoelzmann, p. & lehnhardt, e. (2017): bog iron ore as a resource for prehistoric iron production in central europe – a case study of the widawa catchment area in eastern silesia, poland.− catena, 149, 474–490. doi: 10.1016/j.catena.2016.04.002 török, b. & thiele, a. (2013): extracting phosphoric iron under laboratorial conditions smelting bog iron ores.− in: iop conference series: materials science and engineering, volume 47, 2nd international conference on competitive materials and technological processes (ic-cmtp2) 8–12 october 2012, miskolc-lillafüred, hungary, 012034. doi: 10.1088/1757-899x/47/1/012034 valent, i. (2021): archaeological finds of metallurgical activities on the territory of the river drava basin during iron age and antiquity.− in sekelj ivančan, t., karavidović, t., tkalčec, t., krznar, s. & belaj, j. (eds.), secrets of iron from raw material to an iron object, proceedings of the 7th international scientific conference on mediaeval archaeology of the institute of archaeology, serta instituti archaeologici, zagreb: institut za arheologiju. zaunbrecher, l.k., crawford elliott, w., wampler, j.m., perdrial, n. & kaplan, d.i. (2015): enrichment of cesium and rubidium in weathered micaceous materials at the savannah river site, south carolina.− environ. sci. technol., 49, 4226–4234. doi: 10.1021/es5054682 2022 | 75/2 | 235–247 | 9 figs. | 9 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction groundwater is one of the primary sources of water for various uses. the demand for groundwater will steadily rise in the future. this is a growing problem and more and more attention will be devoted to seeking out methods and strategies for progressively efficient groundwater management. in practice, the water supply for a particualr area is often provided by developing groundwater sources that deliver sufficient water quantities of a satisfactory quality. effective groundwater source management largely depends on local natural conditions, the amount and quality of collected operational data, and the efficient and reliable forecasting of the future water demand and the ability of the hydrogeological setting to meet that demand. roughly 75% of the water demand in serbia relies on groundwater. however, there has been no regular monitoring of surface water and groundwater dynamics during a period of economic crisis in the country, which resulted in an underdeveloped observation network. at groundwater sources, regular monitoring was hindered by poor organization and lack of instrumentation and human resources. more recently, the surface water and groundwater observation network has been expanded based on european union recommendations and the scope and extent of monitoring are now satisfactory. the need to develop methods that will forecast sustainable rates of groundwater abstraction is becoming increasingly pronounced. sufficiently reliable prognostic methods would create conditions for effective conservation of groundwater resources, addressing problems such as inefficient use and over-exploitation, imputing missing data using grey system theory and the biplot method to forecast groundwater levels and yields jelena ratković, dušan polomčić, zoran gligorić and dragoljub bajić* faculty of mining and geology, university of belgrade, đušina 7, 11000 belgrade, serbia; (jmocevic45@gmail.com, dusan.polomcic@rgf.bg.ac.rs, zoran.gligoric@rgf.bg.ac.rs, *correspondence: dragoljub.bajic@rgf.bg.ac.rs) doi: 10.4154/gc.2022.14 abstract groundwater management is one of today’s important tasks. it has become necessary to seek out increasingly reliable methods to conserve groundwater resources. dependable forecasting of the amounts of groundwater that can be abstracted in a sustainable manner requires longterm monitoring of the groundwater regime (rate of abstraction and groundwater levels). monitoring of the groundwater source for the town of bečej, serbia had been disrupted for multiple years. the objective of the paper is to assess the possibility of reinterpreting the missing data or, in other words, to reconstruct the operation of the groundwater source and its effect on groundwater levels. at the bečej source, groundwater is withdrawn from three water-bearing strata comprised of fineto coarse-grained sands. historic data are used to reconstruct the ope ration of the bečej source between 1st of october 1980 to 1st of may 2010. the monitored parameters are total source yield and piezometric head at seven observation wells and 14 pumping wells. a data reconstruction methodology was developed, which included the use of an autoregressive (ar) model, a grey model (gm), and the biplot method. the methodology is applied to fill the data gaps during the considered period. the paper also describes the criteria for evaluating the accuracy of the ar model, gm, and biplot method. the proposed data reconstruction approach yielded satisfactory results and the methodology is deemed useful for the bečej source data, as well as other historic data not necessarily associated with groundwater sources, but also groundwater control and protection systems, as well as hydrometeorological, hydrological and similar uses. which impairs groundwater quality. reliable forecasts of groundwater levels, groundwater balance, and the velocity and direction of groundwater flow play a major role, in view of the fact that they provide important information about the characteristics of the tapped aquifer. with the exception of groundwater quality, forecasting basically focuses on groundwater levels at a particular rate of abstraction. today, many methods are used to forecast groundwater levels, such as nonlinear autoregressive networks (narx) (guzman et al., 2017; wunsch et al., 2018), artificial neutral networks (ann) (nourani et al., 2008; rakhshandehroo et al., 2012; chitsazan et al., 2015; mohanty et al., 2015), time series methods (mirzavand & ghazavi, 2015), arima and rbf networks (yan & ma, 2016), adaptive neuro-fuzzy inference system (anfis) (guldal & tongal, 2009; emamgholizadeh et al., 2014), fuzzy neural networks (alvisi & franchini, 2011), fuzzy c-mean clustering and singular spectrum analysis (polomčić et al., 2017), and hydrodynamic modeling (polomčić et al., 2011; polomčić et al., 2014). the objective of the paper is to present a case study of the bečej groundwater source for drinking water supply (serbia) and demonstrate the reconstruction of missing data (over a 10-year period), using the autoregressive model, the grey system theory and biplot method, in order to improve decision-making related to groundwater management. autoregressive modeling was used as a supplementary method to extract the points in time (dates) of no monitoring. it has been implemented by many other researchers in the fields of article history: manuscript received january 28, 2020 revised manuscript accepted february 04, 2022 available online june 23, 2022 keywords: groundwater management, groundwater source, forecasting g eo lo gi a c ro at ic a geologia croatica 75/2236 hydrology (chakraborty et al, 2009; mehdizadeh, 2020), seismology (xiaojun et al., 2015), exodynamics (yongping et al., 2020), and hydrogeology (ristić vakanjac et al., 2018). many researchers in hydrogeology and similar disciplines have applied the grey system theory to address diverse problems, such as predicting earthquakes (daogong et al., 1999), forecasting of pore pressure changes (mohammed et al., 2010), projecting land subsidence to prevent hazards (tang et al., 2008), sustainable groundwater management for drinking water supply (jianfei et al., 2012), estimating the amount of rainfall and runoff to prevent flooding (yu et al., 2001; kang et al., 2006), forecasting groundwater levels (mahmod et al., 2013; kang & maeng, 2016) and predicting and analyzing spring discharges (hao et al., 2010). the biplot method is also applied by many researchers in different fields. for example, this statistical method has been very useful in addressing environmental protection issues, to predict the evolution of air pollution (gonzalez cabrera et al., 2006; zhang et al., 2018); in mechanics, to solve problems applying svd (singular value decomposition, which is the basis of the biplot method) (meijaard, 1993; gai & hu, 2018); in geophysics, to improve the quality of seismic data (martins et al., 2016) and to determine the spatial relationship between deep geologic structures and gold (zhao & chen, 2010). upon reconstruction of the missing piezometric head data and total groundwater source yields, the gaps in the bečej groundwater source (bečej gs) data were filled over the study period. sufficiently reliable input data were provided to assess the feasibility of bečej gs expansion, predict the long-term effect of groundwater abstraction, and propose optimal solutions for future production wells. 2. study area the study area is the extended area of bečej gs, serbia, as shown in fig. 1. the groundwater source is located west of the city of bečej. groundwater from the tapped aquifers is used for both the municipal and industrial water supplies. between 1980 and 2010, 25 production wells and seven observation wells were drilled at bečej gs. fourteen production wells are currently in service (fig. 1). the others have been decommissioned. the wells tap several aquifers. their individual discharge capacities are 3 – 16 l/s. figure 1. location map of the study area. g eologia c roatica ratković et al.: imputing missing data using grey system theory and the biplot method to forecast groundwater levels and yields 237 table 1. includes the designations of the wells and shows the aquifers they capture. the extended study area is located within the pannonian plain and is composed of precambrian/palaeozoic, mesozoic, miocene, pliocene and quaternary rocks. the oldest rocks are crystalline schists and precambrian/palaeozoic granites. the youngest rocks are quaternary in age, with alternating lithological units (gravels and coarse sands underlie sandy silts, silts and clays) (malešević, 1984; terzin, 1994). vertically, there are two types of aquifers down to a depth of about 130 m: an unconfined intergranular aquifer in the alluvial and terrace deposits (from the land surface to roughly 30 m – aquifer i) and three confined intergranular aquifers in deeper geological formations (from 60 m to 130 m – aquifers ii, iii and iv). bečej gs taps the deeper aquifers of quaternary age: the first is at a depth of 60 to 80 m, the second at 83 to 100 m, and the third from 110 to 130 m (fig. 2). the unconfined aquifer is composed of sands in the upper part and fine-grained, partly clayey sands in the lower part. the bottom of this layer comprises sandy clay. the three deeper aquifers are composed of fineto medium-grained sands, with some gravel. the sands include a pelitic component, which hinders production/causes well ageing. the aquifers are separated by relatively thin layers of clay, sandy clay and clayey sand. their thickness ranges from 5 to 20 m. these three aquifers constitute a hydrogeologic complex, which evolved during the lower and middle pleistocene. on a regional scale, they are considered as a single, confined aquifer (malešević, 1984; terzin, 1994). table 1. well designations and tapped aquifers. active wells tapped aquifers b0-1 second, third b0-2 first, second bi-2/1 second, third bi-3/1 first, second, third bi-5 second, third bi-6 second, third biii-1 first, second, third biii-2 first, second, third biii-3 first, second, third biii-4/1 first, second, third biii-5 third biii-6 second, third bs-5 first, second, third bs-6 first, second, third figure 2. a hydrogeological section through the bečej groundwater source. legend: 1. surface decomposed material; 2. clay; 3. sand; 4. clayey sand; 5. unconfined aquifer; 6. confined aquifer; 7. semi-permeable sediments; 8. confined aquifer head; 9. well; and 10. position of well screen. g eo lo gi a c ro at ic a geologia croatica 75/2238 3. methodology – the forecasting model building process 3.1. problem statement the study period involving groundwater levels and groundwater abstraction rates at bečej gs is from 1 october 1980 to 1 may 2010. however, piezometric head was not monitored from 1 february 1989 to 1 june 1998 and total source yield from 1 october 1980 to 1 june 1998. the monitoring network comprised seven observation wells (p1, p2, p3, p4, p5, p6, p7/2), at depths from 120 m to 150 and 14 pumping wells (b0-1, b0-2, bi-2/1, bi-3/1, bi-5, bi-6, biii-1, biii-2, biii-3, biii-4/1, biii-5, biii-6, bs-5, bs-6), at which total groundwater source capacity was gauged (fig. 3). based on the data, groundwater levels were observed much more frequently than the total source yield. these two parameters were recorded periodically, but slightly more often in 2006 to assess the water balance and determine groundwater reserves. the present research considers mean monthly values of the parameters, which were the only available data (fig. 3). as part of the reported research, a methodology was developed to reconstruct the missing data (10-year period) due to the lack of continuous monitoring. it is shown in fig. 4 in the form of an algorithm. in the first step, input data comprising values observed during the course of monitoring were analyzed. the objective of the proposed methodology was to reconstruct the missing data applying the methods indicated in the algorithm. the ar model was used to reconstruct the dates (observation positions) on which piezometric head and source yield were not observed. the accuracy of the ar model was determined on the basis of aic (akaike information criterion), according to which the lowest value was assumed to be accurate. after the observation dates were reconstructed, the grey method was applied to arrive at piezometric head values for the period during which there was no monitoring. the input data for the gm were the original and reconstructed dates of observation and the observed piezometric heads. first the gm was tested against the (original) data observed during the study period. if a comparison of the original and reconstructed piezometric head data and mape criterion (table 2) indicated that the accuracy of the model was satisfactory, the approach was acceptable for reconstructing the missing data. if not, the proposed methodology was not suitable for further reconstruction. given that calculations and the mape criterion (table 2) indicated that the accuracy of gm was satisfactory, it was applied to fill the data gaps. the above methods used to determine the missing observation dates and piezometric heads produced a completed matrix for the biplot method, which was applied to reconstruct the total source yields during the period of no observations. the accuracy of the total source yields derived by the biplot method was determined based on the condition d y < 0 01. (where: d na x xi i a i na =     −( )       = ∑1 2 1 1 2 , y n yij j p i n =            == ∑∑1 2 11 1 2 ). if the figure 3. piezometric head recorded at bečej gs observation wells from 1 october 1980 to 1 may 2010 and total source yield. g eologia c roatica ratković et al.: imputing missing data using grey system theory and the biplot method to forecast groundwater levels and yields 239 solution was acceptable, the model was deemed suitable for reconstructing the total source yields. if not, it would have been necessary to look for other, more accurate models. all the calculations were made in microsoft excel (ar model, grey theory and biplot method) and mathlab (biplot method). the figures were produced in coreldraw (figs. 1, 2, 4) and microsoft excel (figs. 3, 5, 6, 7, 8, 9). a brief theoretical background of the models used in this research is provided below. 3.2. autoregressive (ar) model the ar model is commonly applied to process statistical timeseries. the ar model was used for predicting missing observation positions. more specifically, it is used to forecast the values of current and future variables, based on the values of the same variable at different times. the variable is described as a function of its values in previous periods zt-1, zt-2. the mathematical expression is (dai et al., 2015): x x zt i i t i t p = + = − ∑a 1 (1) where p is the ar model order and zt is the constant. in order to construct the ar model, first its order (p) needs to be determined. the principle is as follows: for the original (observed) data (x1,x2,...,xn) of order p, the ar model is: x x zt t t i p = +− = ∑a 1 1 (2) if the original time-series is stationary, the ar process is applied directly to the original dataset. if not, the time-series needs to be transformed into a stationary time-series (sequence). the common transformation approach is first-order differentiation, as was required in the present case. first-order differentiation is implemented as: dx x xt t t= − −1 (3) then the ar model can be applied to the differentiated timeseries. the ultimate forecasted values are derived from: 1 ˆ ˆ −= +t t tx x xd (4) where ˆ txd is the value resulting from the ar process. the ar model order is defined (determined) applying aic. aic is calculated as (chakraborty et al., 2009): 2 1 ˆ 2ln =      = +       ∑ n i i u paic n n (5) where n is the length of the sample, p is the number of estimated coefficients (p-order, ar model order) and ˆiu are the residuals. the model where the aic is the lowest is selected as optimal (most suitable). using the ar model, the observation positions (dates) are reconstructed and then used as input data for the gm. 3.3. grey model (gm) the theory provides an effective solution for the data uncertainty and discretization problem. gms predict the future values of a time-series, based solely on a set of observed data (recorded, original values in the present case). according to the grey system theory, a general grey model gm(h,n) is the gm in which h is the order of the differential equation and n is the number of parameters. gm(h,n) is defined by the following differential equation (yu et al., 2001): a d x k dt b x k k ni i l i i h j j j n( ) ( ) ( ) ( )( ) ( ), , ,..., 1 0 1 2 1 2 = = ∑ ∑= = (6) where ai and bj are the determined coefficients, x kl ( ) ( )1 is the sequence of the main factor, x kj ( ) ( )1 are the sequences of the influential factors, and k is the time sequence variable. a single-variable first-order grey model gm(1,1) was used in the present research because there was a single time-series of observations. the original time-series was represented as (zhao-hui & jing, 2016): x x t x t x t j ( ) ( ) ( ) ( )( ), ( ),..., ( )0 0 1 0 2 0=   , j = 1,..., n, if: dtj = tj – tj–1 ≠ const figure 4. operational research algorithm – the forecasting model building process. g eo lo gi a c ro at ic a geologia croatica 75/2240 before proceeding with the gm equation, the accumulating generation operator (ago) will be defined. agos are used in gm to reduce data randomness. the first-order ago for x(0) is defined as (zhao-hui & jing, 2016): x(1) (tj) = x(1) (tj–1) + x(0) (tj) * dtj (7) where (1) (0) 1 ( ) ( ) = =∑ n j j j x t x t . the sequence of the generated averages of the neighboring values of sequence (1) ( )jx t is (1) ( ) =jz t (1) (1) (1)(1), (2),..., ( )  jz z z t , where: (1) (1) (1)1( ) ( )( ( ) ( 1)), 1, 2,..., 2 = + − =j j j jz t x t x t t n (8) the grey differentiated first-order equation gm(1,1) is (zhao-hui & jing, 2016): (1) (1)( ) ( )= + dx t ax t b dt (9) the first term (1) 1( )x t of the sequence (1) ( )( 1, 2,..., )=jx t j n is used as the initial condition of the grey differentiated equation. the solution to eq. (9) is a time-dependent function: x(1)(t) = eat x(1) (t1) + a–1(eat – i)b (10) to distinguish between a and b, eq. (9) is discretized. in other words, the difference in grey derivative i of interval 1,−  j jt t yields (0) (1)( ) ( )= +j jx t az t b and thus: x(0)(tj) = a(z(1) (tj) + z(1) (tj–1)) + b (i = 1,2,..., n; k = 2,3,..., m) (11) coefficients a and b are obtained by the least squares method: (a,b)t = (btb)–1bty (12) where: (1) (1) 2 11 1 (1) (1) (1) 3 21 1 (1) (1) 11 1 1 ( ( ) ( )) 1 2 1 ( ( ) ( )) 1 ( ) 2 ... 1 1 ( ( ) ( )) 1 2 −  +     + =       +   j j j x t x t x t x t b t x t x t (13) (0) (0) (0) 2 3( ), ( ),..., ( ) =   t jy x t x t x t the time sequence response formula, that is, the solution of (9) is: 1 1a(t ) a(t )(1) (1) 1 1( ) ( ) ( )*b− −−= +j jt t jx t e x t a e i j= 1,2,..., n (14) the fitting forecast value of xj(0) can be obtained by the inverse ago, as follows (liu &luo, 2010): (1) (1)(0) 1( ) ( ) ( ) , 2,...,∧ −− = = ∆ j j j j x t x t x t j n t (15) the accuracy of the model is represented by the mean absolute percentage error (mape) (zhao-hui & jing, 2016): 1 1 ( ) = = ∑ n j j mape e t n (16) where: (0) (0) (0) ( ) ( ) ( ) ( ) ∧ − = j j j j x t x t e t x t (17) in the present case, mape was used to assess model accuracy. the model accuracy criterion is shown in table 2 (wang & phan, 2016): the gm (1,1) was used to reconstruct piezometric head data during the 10-year period of discontinued observations (from 1 february 1989 to 1 june 1998, fig. 3). the completed observation positions (dates) and piezometric heads represented input data for the biplot method. 3.4. biplot method the biplot method involves the imputing of arbitrary values to missing data in order to complete the matrix, and then calculating svd using only two components (arciniegas-alarcon et al., 2014). svd is the basis of the biplot method. in the reported case study, the biplot method was used to forecast missing data on total source yields from 1 october 1980 to 1 june 1998. the initial data for constructing the matrix included: 1. original and reconstructed observation positions (dates) on which groundwater level and total source yield were observed); 2. piezometric head data – original and reconstructed using the gm (1,1); and 3. observed source yield data. the constructed nxp matrix denoted by x comprised xij (i=1,...,n; j=1,...,p) elements, where the missing data were symbolized by xij aus. in the first step, the missing values were imputed in their respective columns, to complete matrix x. in the specific case, observed average discharges (i.e. known values) were used to fill the data gaps. the completed matrix x was standardized: ( )− = ij j ij j x m p s (18) where: mj is the mean deviation of the j-th column, sj is the standard deviation of the j-th column, and pij are the standardized elements. the matrix with pij elements was denoted by p. the next step was to calculate svd of matrix p. svd of a standardized matrix is a fundamental and prominent approach in modern numerical linear algebra. the svd algorithm represents an approximation of the main matrix by smaller matrices (meitable 2. accuracy according to mape (%). mape (%) forecast (prediction) accuracy < 1 high 1-5 good 5-10 acceptable >10 unacceptable (low) g eologia c roatica ratković et al.: imputing missing data using grey system theory and the biplot method to forecast groundwater levels and yields 241 jaard, 1993). according to this theorem, any matrix a (mxn) can be decomposed into three matrices, as: a = ulvt (19) u is the orthogonal mxm matrix, v is the orthogonal nxn matrix, l is the diagonal mxn matrix with positive elements on the main diagonal, referred to as singular values of a, and all the other terms are equal to zero. the singular values are generally sorted in descending order, on the main diagonal l. taking into account the first two components, the resulting equation (expression) is: 2 1 ( ) λ α γ ε = − = = +∑ij j ij k ik jk ij j k x m p s (20) lk are the singular values, aik are the eigenvectors of the rows, gjk are the eigenvectors of the columns, and eij is the error of row i in column j. the new matrix, composed of pij (2) elements, was denoted by p(2). all the pij (2) elements in p(2) were re-assigned their original values, (2) (2)∧ = +ij j j ijx m s p . this resulted in a new matrix – x(2) (n×p). the xij aus missing in the original matrix x were imputed with the corresponding values of ∧xij (2) in x(2). filling of data gaps was followed by iterations (back to matrix standardization, repeating the entire process) until the specified condition ( 0.01− < d y ) was fulfilled and the imputed missing values stabilized. the iterations then continued until the following condition was met (arciniegas-alarcon et al., 2014): 0.01− < d y (21) where: 1 2 2 1 1 ( ) na a i i i d x x na =     = −     ∑ (22) and 1 2 2 1 1 1 pn ij i j y y n = =    =      ∑∑ (23) – na is the total number of values missing in matrix x, – xi is the value forecasted for the i-th row of missing values in the active iteration, – xi a is the value forecasted for the i-th missing values in the previous iteration, – yij are the original values (not missing) in the i-th row and j-th column, and – n is the total number of considered values. 4. results and discussion – application of the methodology to a real case study before the missing data were reconstructed, the hydrogeological system was analyzed based on data collected in the last 30 years of operation to determine the groundwater dynamics. the unconfined intergranular aquifer (aquifer i) is relatively thin and the values of its hydraulic parameters are low, so the groundwater reserves are modest. this aquifer is recharged by precipitation and via a good hydraulic link with a river. the aquifer is drained by the pumping wells and by migration into the deeper aquifers, given the semi-permeable floor of aquifer i. recharge of the confined intergranular aquifers (ii, iii and iv) is highly complex because of the large distances involved, so the recharge process can only be assumed based on the geological and hydrogeological features of the terrain and long-term piezometric levels of the groundwater. in view of the fact that the spread of the aquifers is regional, recharge occurs over a large area where their overlying strata are dominated by sands or in zones where the aquifers are directly linked to the land surface or rivers. infiltration of precipitation into the confined aquifers has not been confirmed or occurs on a small scale. it is assumed that recharge also takes place through groundwater migration from the first, unconfined aquifer, given that the strata overlying aquifer ii are composed of sands, clayey sands and sandy clays, which allow partial groundwater infiltration from aquifer i. this infiltration rate is very slow. the confined aquifers are drained solely by the studied pumping wells and neighbouring groundwater sources. all the observation wells registered identical piezometric head fluctuation trends – lower in the summer and early autumn months due to higher rates of groundwater abstraction. given the amount of water withdrawn from these aquifers, this decrease indicates that recharge conditions are satisfactory. the total average monthly yield of the groundwater source suggests that the amount of abstracted groundwater has not changed significantly compared to 10 years ago. the recorded piezometric level ranged from a minimum of 65 m above sea level to a maximum of 76 m.a.s.l., while the total source yield was from 68 l/s to 124 l/s. the missing data reconstruction results are described below. records of groundwater abstraction rates since the groundwater source was commissioned (a period of 30 years, fig. 3 provided input data for applying the gm (1,1) and biplot method to bečej gs. the missing data were reconstructed according to the algorithm shown in fig. 4, first the observation dates using the ar model, then the groundwater levels resulting from gm (1,1), and finally the total source yield applying the biplot method. the proposed methodology with regard to the period of no observations is described below. 4.1. imputing of missing observation positions based on the ar model the ar model was used to forecast observation data (dates) of piezometric head and total source yield. observation date is the date (day, month and year) of measurement. for ar modeling figure 5. original piezometric head observation positions at all observation wells. g eo lo gi a c ro at ic a geologia croatica 75/2242 purposes, these dates were converted into cumulative days (fig. 3 shows the dates of original measurement). each observation date is identified as an observation position in order to define the total number of measured and later reconstructed values (125 measured and 38 reconstructed). given that the original time-series was transient (fig. 5) and in view of the growing trend resulting from eq. (3), first-order differentiation (fig. 6) was needed in order to apply the ar model. time-series that exhibit a trend are referred to as non-stationary. equation (1) was applied to the stationary time-series, the values for the ar models of the second, third and fourth orders were calculated, and then the aic criterion was used to assess the most accurate solution. aic was applied to second-, thirdand fourth-order ar (ar2, ar3 and ar4). the results based on eq. (5) are shown in table 3. the lowest aic value was adopted (i.e. second-order ar, ar2). figure 7. shows the original dates (in red) from 1 october 1980 to 1 february 1989, based on which the missing dates (shown in blue) were reconstructed, along with subsequent original dates (1 june 1998 to 1 may 2010). table 4. is a numerical representation of the forecasted observation positions based on second-order ar. the dates shown in red were reconstructed (there were no actual piezometric head and source yield observations). the mape of ar2 was 2.26 %. in view of the large number of missing observation dates, this error was deemed acceptable. also, ar2 was adopted according to aic. 4.2. imputing of missing piezometric head data based on the gm the input data used in this research were considered to be a grey system, with some known and some unknown information, so that it could be analyzed applying the grey system theory. the first step was to analyze the input data from 1 october 1980 to 1 may 2010, and the second step to apply a gm (1,1). the gm (1,1) was used to reconstruct piezometric head values for the period during which the observation wells (p1, p2, p3, p4, p5, p6, p7-2) were not monitored. the first step was to verify the accuracy of the gm (1,1) using the observed data. figure 6. stationary time-series of original observation positions at all observation wells. table 3. aic values for ar2, ar3 and ar4. aic(ar2) aic(ar3) aic(ar4) 7.43 7.44 7.44 table 4. reconstructed observation positions based on second-order ar. observation position day observation position day observation position day observation position day 1 1 19 1827 37 3315 55 4924 2 183 20 1888 38 3405 56 5013 3 274 21 1919 39 3494 57 5102 4 397 22 2009 40 3583 58 5192 5 517 23 2100 41 3673 59 5281 6 639 24 2162 42 3762 60 5371 7 762 25 2374 43 3851 61 5460 8 854 26 2435 44 3941 62 5549 9 882 27 2527 45 4030 63 5639 10 1004 28 2557 46 4119 64 5728 11 1127 29 2618 47 4209 65 5817 12 1248 30 2680 48 4298 66 5907 13 1309 31 2740 49 4388 67 5996 14 1370 32 2831 50 4477 68 6085 15 1462 33 2954 51 4566 69 6175 16 1613 34 3046 52 4656 70 6264 17 1674 35 3136 53 4745 71 6353 18 1735 36 3226 54 4834 72 6443 figure 7. original and reconstructed observation positions according to second-order ar. g eologia c roatica ratković et al.: imputing missing data using grey system theory and the biplot method to forecast groundwater levels and yields 243 equations (7) through (15), described in the theoretical section, were applied in that order to the original time-series of observed piezometric head data. this yielded the predicted piezometric head values. the objective was to check the accuracy and applicability of the gm to the case study or, in other words, to the original measured data (table 5). then eq. (16) was applied to the reconstructed time-series to check the calculation error and table 2. was used to assess whether the gm was applicable to the original time-series and if it yielded acceptable solutions. table 5. shows the observed (original) and reconstructed piezometric heads at observation well p1. it is apparent that the difference between the observed and reconstructed values was acceptable according to the criterion from table 2 and that the model could be used for the discontinued period from 2 january 1989 to 6 january 1998. the errors are shown in table 6. the observed and reconstructed piezometric head values agreed rather well, given the ten-year period of discontinued table 5. observed (original) and reconstructed values of piezometric head at observation well p1 and absolute error. day p1 original time-series p1 recon. time-series abs. error day p1 original time-series p1 recon. time-series abs. error day p1 original time-series p1 recon. time-series abs. error 1 74.57 74.57 0.00 7063 67.69 68.76 1.58 9497 67.94 67.72 0.33 183 74.74 71.69 4.08 7184 67.68 68.70 1.50 9528 67.82 67.71 0.17 274 74.59 71.63 3.97 7245 67.02 68.66 2.44 9558 67.89 67.69 0.29 397 74.41 71.58 3.80 7276 66.49 68.64 3.23 9589 68.41 67.68 1.07 517 75.01 71.53 4.64 7306 66.59 68.63 3.06 9620 68.64 67.67 1.42 639 74.50 71.48 4.05 7337 66.63 68.61 2.98 9648 68.52 67.66 1.26 762 74.11 71.43 3.62 7367 66.68 68.60 2.88 9679 68.98 67.64 1.94 854 73.28 71.38 2.59 7398 67.07 68.59 2.26 9709 68.60 67.63 1.41 882 72.77 71.35 1.95 7549 66.71 68.55 2.76 9740 68.20 67.62 0.85 1004 72.55 71.32 1.69 7610 66.74 68.51 2.65 9770 68.29 67.61 1.00 1127 72.18 71.27 1.26 7763 67.37 68.46 1.62 9801 68.09 67.59 0.73 1248 72.13 71.22 1.27 7822 67.52 68.42 1.33 9832 67.54 67.58 0.06 1309 71.11 71.18 0.09 7853 67.50 68.40 1.33 9862 67.83 67.57 0.38 1370 71.42 71.15 0.38 7914 67.34 68.38 1.54 9893 67.74 67.56 0.27 1462 70.78 71.12 0.48 7975 66.62 68.35 2.60 9923 67.94 67.54 0.58 1613 70.65 71.06 0.59 8067 66.91 68.32 2.11 9985 68.14 67.53 0.90 1674 71.27 71.02 0.35 8097 66.61 68.30 2.53 10014 68.39 67.51 1.29 1735 70.99 70.99 0.00 8159 67.58 68.28 1.03 10045 68.79 67.49 1.88 1827 70.79 70.96 0.24 8248 67.38 68.25 1.29 10075 68.60 67.48 1.63 1888 70.44 70.93 0.69 8309 66.15 68.22 3.12 10106 68.06 67.47 0.87 1919 70.91 70.91 0.01 8371 66.00 68.19 3.32 10136 67.74 67.46 0.42 2009 70.68 70.88 0.28 8462 67.43 68.16 1.08 10167 67.52 67.44 0.11 2100 70.39 70.84 0.64 8524 68.08 68.13 0.07 10198 67.59 67.43 0.23 2162 70.15 70.81 0.94 8614 68.44 68.10 0.50 10228 67.87 67.42 0.66 2374 70.30 70.75 0.64 8675 68.24 68.06 0.26 10259 67.47 67.41 0.09 2435 70.35 70.69 0.48 8737 68.23 68.04 0.28 10289 67.89 67.39 0.73 2527 70.03 70.66 0.90 8767 68.32 68.02 0.44 10320 68.08 67.38 1.03 2557 70.00 70.63 0.90 8828 68.72 68.00 1.05 10351 68.17 67.37 1.18 2618 70.09 70.61 0.75 8949 69.08 67.96 1.62 10379 68.46 67.36 1.61 2680 70.11 70.59 0.68 8979 69.23 67.93 1.87 10410 68.59 67.34 1.82 2740 70.09 70.56 0.67 9071 67.77 67.91 0.20 10440 68.57 67.33 1.80 2831 69.71 70.53 1.17 9102 67.84 67.88 0.06 10471 68.57 67.32 1.82 2954 69.41 70.48 1.54 9132 68.01 67.87 0.21 10501 68.57 67.31 1.84 3046 68.51 70.44 2.81 9163 68.06 67.86 0.30 10532 68.49 67.30 1.74 6453 66.59 69.69 4.66 9193 68.32 67.84 0.70 10563 68.39 67.28 1.62 6483 66.59 68.97 3.57 9255 68.85 67.82 1.49 10593 68.56 67.27 1.88 6514 65.99 68.96 4.49 9283 68.75 67.81 1.37 10654 68.74 67.25 2.17 6545 64.99 68.94 6.08 9314 68.99 67.79 1.73 10685 68.69 67.23 2.12 6575 65.54 68.93 5.17 9344 70.41 67.78 3.73 10744 68.99 67.21 2.57 6606 65.89 68.92 4.60 9375 68.89 67.77 1.63 10775 68.92 67.20 2.50 6698 66.49 68.89 3.61 9436 67.95 67.75 0.29 10805 69.49 67.18 3.32 6879 66.69 68.83 3.22 9467 68.22 67.73 0.72 g eo lo gi a c ro at ic a geologia croatica 75/2244 groundwater monitoring (table 5). based on the criterion shown in table 2, the conclusion was that the error was acceptable in view of the fact that the accuracy of the reconstructed values was high, so the solution was deemed acceptable. 4.3. imputing of missing source yield data based on the biplot method the biplot method was used to reconstruct the missing source yield data, from 1 october 1980 to 1 july 1998. the input data in this case included original and reconstructed: – observation dates, – piezometric heads and – observed source yield data. the first step, before the biplot method, was to complete matrix x for calculating the missing total source yield values. the averages of the observed source yields were used for the missing values, xij aus. the completed matrix included the observation dates (original and reconstructed), piezometric heads (original and reconstructed), observed source yields and average source yields (in place of those that needed to be reconstructed). matrix x was than standardized applying eq. 18, resulting in standardized matrix p. this was followed by the svd of matrix p (in matlab), based on eq. 19. then eq. 20 was applied, resulting in matrix p(2). after applying (2) (2) ij j j ijx m s p ∧ = + , all the elements of that matrix reverted to original values in matrix x(2) (nxp). the missing xij aus in the original matrix x were completed with the corresponding values of x ∧ ij (2) iz x(2). this was followed by iterations, back to matrix standardization, and the entire process was repeated. iterations lasted until the condition 0.01d y− < was fulfilled (arciniegas-alarcon et al., 2014), which occurred in the second iteration (table 7). table 8 and figure 8 show the observed (original) and reconstructed source yields. table 6. reconstructed piezometric head errors at all observation wells. max. abs. error mape (%) p1 6.08 1.60 p2 4.42 1.34 p3 3.31 1.16 p4 4.51 1.40 p5 3.61 1.02 p6 3.81 1.27 p7-2 5.83 1.66 table 8. observed (original) and reconstructed source yields – iteration 2. day q original time-series q reconst. time-series day q original time-series q reconst. time-series day q original time-series q reconst. series 6483 95.31 93.18 8614 106.28 106.08 9832 98.10 98.15 6514 96.99 95.85 8675 116.34 113.58 9862 99.40 98.39 6545 104.60 99.85 8737 109.64 109.02 9893 100.72 97.37 6575 101.23 97.75 8767 105.43 108.55 9923 100.29 93.04 6606 98.06 97.95 8828 96.55 101.54 9985 100.73 94.78 6698 101.41 100.84 8949 94.83 97.10 10014 97.35 93.02 6879 93.87 94.02 8979 96.86 97.34 10045 95.14 92.17 7063 91.33 86.23 9071 105.12 101.47 10075 95.83 92.19 7184 99.94 92.97 9102 103.90 100.80 10106 95.86 92.81 7245 105.14 101.06 9132 103.47 99.98 10136 97.43 94.89 7276 104.93 102.58 9163 97.93 96.67 10167 97.71 95.77 7306 98.80 99.41 9193 95.82 94.82 10198 90.37 92.84 7337 100.77 100.84 9255 97.66 94.33 10228 92.88 92.99 7367 101.13 101.91 9283 95.60 92.87 10259 87.41 89.06 7398 100.97 100.85 9314 94.68 91.59 10289 86.34 88.36 7549 104.38 105.04 9344 96.76 91.21 10320 86.97 88.42 7610 102.22 103.67 9375 99.93 94.22 10351 83.21 86.20 7763 100.82 102.24 9436 97.11 94.61 10379 78.58 82.91 7822 98.87 100.19 9467 93.47 92.56 10410 79.41 83.37 7853 99.52 101.09 9497 96.28 93.79 10440 77.86 82.76 7914 99.53 101.06 9528 96.59 92.61 10471 81.66 87.75 7975 96.76 100.87 9558 92.51 89.59 10501 86.99 90.80 8067 98.54 103.96 9589 92.61 86.49 10532 82.75 90.24 8097 96.35 103.06 9620 92.85 86.91 10563 78.07 87.35 8159 94.78 100.60 9648 94.74 91.53 10593 67.28 81.33 8248 105.43 105.68 9679 95.66 90.18 10654 87.77 91.09 8309 112.72 112.49 9709 94.59 93.39 10685 87.84 90.26 8371 123.38 118.85 9740 97.82 95.18 10744 105.61 99.02 8462 112.00 110.48 9770 103.30 99.40 10775 85.27 86.95 8524 113.51 111.08 9801 100.54 97.68 10805 81.44 83.75 g eologia c roatica ratković et al.: imputing missing data using grey system theory and the biplot method to forecast groundwater levels and yields 245 it is apparent in figure 8. that the original and reconstructed source yield data agree rather well, over the entire study period (from 1 october 1980 to 1 may 2010). table 9. shows the errors in the 2nd iteration. figure 9. shows the bečej gs observed and reconstructed piezometric head and source yield data. table 7. condition for ending iterations. d y d y 1.417 246.031 0.006 figure 8. observed (original) and reconstructed source yield data (2nd iteration). figure 9. original (observed) and reconstructed piezometric head and total source yield at all observation wells of bečej gs. g eo lo gi a c ro at ic a geologia croatica 75/2246 figure 9. shows that the trends of the piezometric head and source yield data are consistent with those registered in situ. the reason for the lack of fluctuations of the reconstructed values is attributable to the long period of time during which the considered parameters were not observed, as the applied methodology cannot produce more accurate solutions. however, the proposed methodology was highly effective in the study area, given that all the solutions were within the set criteria and the errors were in the predefined range. the models used in this research yielded satisfactory results and it is believed that they can be applied to fill data gaps in the study area (bečej, serbia). the developed methodology can also serve as a tool for upgrading other models (e.g. hydrodynamic) in groundwater management, when available input data are insufficient for this type of analysis. the level of error associated with the proposed methodology indicates that it can be applied to other groundwater sources and groundwater management systems. 5. conclusion an adequate groundwater source monitoring database is essential for efficient decision making in groundwater resources management. when such data are lacking, it is a challenge to provide sufficiently reliable groundwork for forecasting the future status of a groundwater source and the regime of the captured groundwater. the paper described a methodology developed to reconstruct missing piezometric head and source yield data because monitoring of the bečej groundwater source (bečej gs) had been discontinued for a period of ten out of 30 years. the accuracy of the reconstructed values was first assessed in respect of the observed (original) data. mape showed that the applied models were highly accurate, indicating that the methodology could be applied to the entire time series of data observed during the study period. temporarily discontinued monitoring of piezometric head and source yield is one of the problems that had an adverse effect on the reliability of decisions relating to the feasibility of expanding the groundwater source in the future, in view of the potential of the area and the predicted efficiency of groundwater abstraction over a long period of time. the proposed methodology effectively solves that problem. the implementation of the proposed algorithm, resulting in complete input data, improved source expansion solutions based on one of many methods for predicting groundwater dynamics. in the specific case, future research will focus on hydrodynamic modeling with reconstructed and filled data gaps for bečej gs. the proposed, verified methodology can be applied to groundwater abstraction systems, but also other systems, such as groundwater control (mines, hydraulic structures, agriculture, industrial zones, and urban areas), groundwater protection, and hydrometeorological, hydrological and similar systems. the advantage of the proposed methodology is that it ensures sufficiently reliable reconstruction and/or forecasting of needed parameters, in cases that involve a small amount of observed data, or known quantities. in some instances it is relatively simple to implement. author contributions: all authors discussed the results and contributed to the final manuscript. j.r. with d.p., z.g. and d.b. designed the methodology and wrote the final manuscript. research plan, fieldwork and initial data analysis was conducted by j.r. d.b. provided critical feedback and helped shape the research methodology. funding: this research received no external funding. conflicts of interest: the authors declare no conflicts of interest. acknowledgment the authors express their gratitude to the serbian ministry of education, science and technological development for supporting scientific research, which is essential for the advancement of a knowledge based society. references alvisi, s. & franchini, m. (2011): fuzzy neural networks for water level and discharge forecasting with uncertainty.– environmental modelling & software, 26, 523–537. doi: 10.1016/j.envsoft.2010.10.016 arciniegas-alarcon, s., garcia-pena, m., krzanowski, wj. & dias, c.t.s. (2014): imputing missing values in multi-environment trials using the singular value decomposition: an empirical comparison.– international journal of the faculty of agriculture and biology, 9, 54–70. doi: 10.1590/1984-70332016v16n2a13 chakraborty, s., denis, d.m. & sherring, a. (2009): development of time series autoregressive model for prediction of rainfall and runoff in kelo watershed chhattisgarh.– international journal of advances in engineering science and technology, 2, 153–163. chitsazan, m., rahmani, g. & neyamadpour, a. (2015): forecasting groundwater level by artificial neural networks as an alternative approach to groundwater modeling.– journal of the geological society of india, 85, 98–106. doi: 10.1007/s12594-015-0197-4 dai, x., liu, j. & zhang, h. (2015): application of ar model in the analysis of preearthquake ionospheric anomalies.– mathematical problems in engineering, id id 157184. doi: 10.1155/2015/157184 daogong, h.u., shuren, w.u. & chengxuan, t.a.n. (1999): grey prediction of seismic activity in the three gorges area of the yangtze river.– acta geologica sinica, 73, 294–299. emamgholizadeh, s., moslemi, k. & karami, g. (2014): prediction the groundwater level of bastam plain (iran) by artificial neural network (ann) and adaptive neuro-fuzzy inference system (anfis).– water resources management, 28, 5433–5446. doi: 10.1007/s11269-014-0810-0 gai, j. & hu, y. (2018): research on fault diagnosis based on singular value decomposition and fuzzy neural network.– shock and vibration, id 8218657. doi: 10.1155/2018/8218657 gonzalez cabrera, j.m., fidalgo martinez, m.r., martin mateos, e.j. & vicente tavera, s. (2006): study of the evolution of air pollution in salamancam (spain) along a five-year period (1994–1998) using hj-biplot simultaneous representation analysis.– environmental modelling & software, 21, 61–68. guldal, v. & tongal, h. (2009): comparison of recurrent neural network, adaptive neuro-fuzzy inference system and stochastic models in egirdir lake level forecasting.– water resources management, 24, 105–128. doi: 10.1007/s11269009-9439-9 guzman, s.m., paz, j.o. & tagert, m.l.m. (2017): the use of narx neural networks to forecast daily groundwater levels.– water resources management. 31, 1591–1603. doi: 10.1007/s11269-017-1598-5 hao, y., zhang, l., wei, t. & wang, x. (2010): piecewise analysis and prediction of spring flow based on gm(1,1).– advances in grey systems research, doi: 10.1007/978-3-642-13938-3_14 jianfei, f., lun, z., zhiguo, l. & jianying, y. (2012): study on the sustainable utilization of groundwater resources in hebei plain.– procedia environmental sciences, 12, 1071–1076. doi: 10.1016/j.proenv.2012.01.389 kang, m.g. & maeng, sj. (2016): gray models for real-time groundwater-level forecasting in irrigated paddy-field districts.– journal of irrigation and drainage engineering. doi: 10.1061/(asce)ir.1943-4774.0000940 table 9. second iteration errors iteration 2 (%) min. error -7.78 max. error 17.27 mape 3.32 g eologia c roatica ratković et al.: imputing missing data using grey system theory and the biplot method to forecast groundwater levels and yields 247 kang, m.s., kang, m.g., park, s.w., lee, j.j. & yoo, k.h. (2006): application of grey model and artificial neural networks to flood forecasting.– journal of the american water resources association (jawra), 42, 473–486. liu, q. & luo, y. (2010): the non-equidistant linear weighting grey model nwgm (1,1) and its application.– international journal of simulation systems, science & technology, doi: 10.5013/ijssst.a.17.25.28 mahmod, w.e., watanabe, k. & zahr-eldeen, a.a. (2013): analysis of groundwater flow in arid areas with limited hydrogeological data using the grey model: a case study of the nubian sandstone, kharga oasis, egypt.– hydrogeology journal, 21, 1021–1034. doi: 10.1007/s10040-013-0959-2 malešević, m. (1984): state geological map of sfry, scale 1:100.000, srbobran section (map and guide).– federal geological survey, belgrade. martins, w.o., porsani, m.j. & silva, m.g. (2016): adaptive singular value decomposition filtering to enhance reflectors and geological structures in 3d seismic data.– revista brasileira de geofısica, 34, 1–9. doi: 10.22564/rbgf.v34i2.797 mehdizadeh, s. (2020): using ar, ma, and arma time series models to improve the performance of mars and knn approaches in monthly precipitation modeling under limited climatic data.– water resources management (2020), 34, 263–282. doi: 10.1007/s11269-019-02442-1 meijaard, j.p. (1993): applications of the singular value decomposition in dynamics.computer methods in applied mechanics and engineering, 103, 161–173. doi: 10.1016/0045-7825(93)90044-x mirzavand, m. & ghazavi, r. (2015): a stochastic modelling technique for groundwater level forecasting in an arid environment using time series methods.–water resources management, 29, 1315–1328. doi: 10.1007/s11269-0140875-9 mohammed, m., watanabe, k. & takeuchi, s. (2010): grey model for prediction of pore pressure change.– environmental earth sciences, 60, 1523–1534. doi: 10.1007/s12665-009-0287-y mohanty, s., jha, m.k., raul, s., panda, r. & sudheer, k. (2015): using artificial neural network approach for simultaneous forecasting of weekly groundwater levels at multiple sites.– water resources management, 29, 5521–5532. doi: 10.1007/s11269-015-1132-6 nourani, v., mogaddam, a.a. & nadiri, a.o. (2008): an ann-based model for spatiotemporal groundwater level forecasting.– hydrological processes, 22, 5054–5066. doi: 10.1002/hyp.7129 polomčić d., gligorić z., bajić d. & cvijović č. (2017). a hybrid model for forecasting groundwater levels based on fuzzy c-mean clustering and singular spectrum analysis.– water, 9/7, 541 (2017). doi: 10.3390/w9070541 polomčić, d., bajić, d. & krunić, o. (2014): hydrodynamic analysis of the interaction of two operating groundwater source, case study: groundwater supply of bečej.– tehnika, 65, 597–603. doi: 10.5937/tehnika1404597p polomčić, d., krunić, o. & ristić vakanjac, v. (2011): hydrogeological and hydrodynamic characteristics of groundwater sources for the public water supply of bečej (northern serbia).– annales géologiques de la péninsule balkanique, 72, 143–157. rakhshandehroo, g.r., vaghefi, m. & aghbolaghi, m.a. (2012): forecasting groundwater level in shiraz plain using artificial neural networks.– arabian journal for science and engineering, 37, 1871–1883. doi: 10.1007/ s13369-012-0291-5 ristić vakanjac, v., čokorilo ilić, m., papić, p., polomčić, d. & golubović, r. (2018): ar, cr and arcr modeling for simulations and analyses of karst groundwater quality parameters.– geoloski anali balkanskog poluostrva, 79, 71–81. doi: 10.2298/gabp1879071r tang, y.q., cui, z.d., wang, j.x., yan, l.p. & yan, x.x. (2008): application of grey theory-based model to prediction of land subsidence due to engineering environment in shanghai.– environmental geology, 55, 583–593. doi: 10.1007/ s00254-007-1009-y terzin, v. (1994): state geological map of sfry, scale 1:100.000, zrenjanin section (map and guide).– federal geological survey, belgrade. wang, c.n. & phan, v.t. (2016): an improvement the accuracy of grey forecasting model for cargo throughput in international commercial ports of kaohsiung.– wseas transactions on business and economics, 11, 322–327. doi: 10.11648/j. ijber.20140301.11 wunsch, a., liesch, t. & broda, s. (2018): forecasting groundwater levels using nonlinear autoregressive networks with exogenous input (narx).– journal of hydrology, 567, 743–758. doi: 10.1016/j.jhydrol.2018.01.045 xiaojun, d., jianjun, l. & huaying z. (2015): application of ar model in the analysis of preearthquake ionospheric anomalies.– mathematical problems in engineering, id 157184. doi: 10.1155/2015/157184 yan, q. & ma, c. (2016): application of integrated arima and rbf network for groundwater level forecasting.– environmental earth sciences, 75/5, 1–13. doi: 10.1007/s12665-015-5198-5 yongping, c., min, g., shunqi, p., haidong, p., xian, z. & zhengjin, t. (2020): application of auto-regressive (ar) analysis to improve short-term prediction of water levels in the yangtze estuary.– journal of hydrology, 590, 125386. doi: 10.1016/j.jhydrol.2020.125386 yu, p.s., chen, c.j., chen, s.j. & lin, s.c. (2001): application of grey model toward runoff forecasting.– journal of the american water resources association (jawra), 37, 151–166. doi: 10.1111/j.1752-1688.2001.tb05482.x zhang, l., liu, y. & zhao, f. (2018): singular value decomposition analysis of spatial relationships between monthly weather and air pollution index in china.– stochastic environmental research and risk assessment, 32, 733–748. doi: 10.1007/ s00477-017-1491-z zhao, b.b. & chen, y.q. (2010): singular value decomposition (svd) for extraction of gravity anomaly associated with gold mineralization in tongshi gold field, western shandong uplifted block, eastern china.– nonlinear processes geophysics, 18, 103–109. doi: 10.5194/npg-18-103-2011 zhao-hui, h. & jing, l. (2016): the non-equidistance and non-homogeneous multivariable grey nnmgm(1,n) model and its application.– journal of residuals science & technology, 13, 23.1–23.8. ab stra ct this paper presents research on the surface characteristics, specific surface area (ssa), cation exchange capacity (cec) and the electrophoretic mobility (epm) of kaolin clays obtained from different naturally occurring pegmatite and granite deposits worldwide. particular emphasis was placed on studying the influence of ancillary minerals on these properties, as well as the diversity in morphological and structural characteristics of kaolinite in samples. min­ eral composition and the morphology of the kaolin samples were investigated using x-ray diffraction (xrd) and field emission scanning electron microscope (fe-sem), respectively. the ssa was determined by the bet method, cec by ammonium selective electrode and surface charge by epm measurements. results showed that the surface properties of the kaolin samples were strongly influenced by the presence of ancillary constituents, particularly smec­ tite minerals. their occurrence, even in trace amounts, significantly increased the ssa and cec values of the inves­ tigated samples. most importantly, epm measurements revealed that the character of the amphoteric surfaces of the dominant kaolinite mineral in the samples was rescinded by the permanent ph-independent siloxane basal charge of smectite. the presence of ancillary smectites, characterized by higher surface reactivity, hindered the surface proper­ ties of the prevailing kaolinite mineral in the kaolin clay deposits. keywords: kaolin clays, igneous deposits, ancillary minerals, surface properties mineralogy, surface properties and electrokinetic behaviour of kaolin clays derived from naturally occurring pegmatite and granite deposits  maja ivanić1, neda vdović1, sandra de brito barreto2, vladimir bermanec3 and ivan sondi4* 1 division for marine and environmental research, ruđer bošković institute, bijenička c. 54, zagreb, croatia 2 department of geology, federal university of pernambuco, recife pe, brazil 3 division of mineralogy and petrology, faculty of science, horvatovac 95, zagreb, croatia 4 department of mineralogy, petrology, and mineral resources, faculty of mining, geology and petroleum engineering, pierottijeva 6, zagreb, croatia; (corresponding author: ivan.sondi@rgn.hr) doi: 10.4154/gc.2015.09 and deposition of organic and inorganic compounds (grim, 1968; newman, 1987; sondi & pravdić, 2002; ber­ gaya et al., 2006). they are the omnipresent components of suspended matter, soils and modern sediments that appear mainly in the form of colloids and nanoparticles (theng & yuan, 2008). their role should be considered in simul­ taneous and complex physico-chemical interactions that in­ volve, besides clay minerals, humic matter and/or iron and manganese oxides/oxyhydroxides as natural surface coat­ ings (chekli et al., 2013). the investigation of clay mine­ geologia croaticageologia croatica 1. introduction the term clay minerals refers to the naturally occurring layer-type aluminosilicate minerals, which contain structural hydroxyl groups and belong to the general class of phyllo­ silicates (grim, 1968; bailey, 1980). due to their over­ whelming structural and chemical diversities and related unique surface physico-chemical properties, clay minerals attract considerable interest in biogeochemical processes, particularly in chemical binding, transport, transformation geologia croatica 68/2 139–145 5 figs. 2 tabs. zagreb 2015 geologia croatica 68/2geologia croatica 140 ral surfaces and their interactions with organic and inorganic compounds is crucial for understanding their role in geo­ chemical cycles in the natural environment (sondi et al., 1996a; sondi & pravdić, 2002). surfaces of clay minerals are structurally, morphologi­ cally and chemically heterogeneous. in general, they exhibit two morphological planes of different structure, chemical composition and consequently, different surface properties (van olphen, 1951; sposito, 1984; zhou & gunter, 1992). these are the siloxane surface basal layer characterized by a permanent negative charge arising from isomor­ phic substitutions (mostly of si4+ by al3+) in the crystal structure, and the edge surface (broken bonds) characterized by the variable amphoteric charge (moore & reynolds, 1997). the contribution of these surfaces to the total exter­ nal surface area depends on the type of clay minerals. for kaolinite, the edge fraction occupies 12 to 14 % of the total surface area (ferris & jepson, 1975; james & wil­ liams, 1982). for smectite clays, it is no more than 1%, and for illite 2–10% (wan & tokunaga, 2002). studies on the physical disintegration of clay mineral particles have shown significant alteration of their surface properties gov­ erned by the ratio between the siloxane and edge surfaces (sondi & pravdić, 1996b; sondi et al. 1997a; vdović et al., 2010). numerous studies concerning the surface properties of clay mineral particles, mostly kaolinite and montmorillonite, have been reported in the literature (herrington et al., 1992; sondi & pravdić, 1996b; sondi et al., 1997a,b; zhuang & yu, 2002; tombácz & szekeres, 2004, 2006). clay minerals occur in nature mainly in complex min­ eral assemblages, together with numerous inorganic and or­ ganic compounds, mostly in the form of surface coatings. while the effects of organic and inorganic surface coatings on the reactivity of clay mineral particles have been the sub­ ject of numerous studies (zhuang & yu, 2002; sondi et al., 1997b), the influence of mineral phases present in mi­ nor amounts has been neglected, despite the fact that even commercial clay deposits contain various amounts of differ­ ent mineral constituents accompanying the dominant clay mineral phase (jepson, 1988). when dealing with natural clay minerals, the main dif­ ficulty is their separation from the rest of the mineral and organic constituents. this involves various physical and chemical procedures that are rarely completely efficient in the removal of all impurities and often cause significant changes and modifications of the native physico-chemical table 1: sample information and qualitative mineralogical composition of the investigated kaolin clays. sample location major component minor component s1 mamoes, equador kaolinite muscovite, quartz s2 jacu, brazil kaolinite muscovite, quartz s3 almas, parelhas (2003) kaolinite muscovite, quartz, feldspars s4 sierra leone kaolinite muscovite, quartz, feldspars, smectites s5 almas, parelhas (2004) kaolinite muscovite, quartz, feldspars, smectites properties of clay mineral surfaces. therefore, the use of clay minerals from primary igneous deposits appears to be help­ ful in studying their native surface properties. their surfaces, unlike those found in pedogenic or sedimentary environ­ ments, are free of organic matter and they are not signifi­ cantly altered by the presence of inorganic surface coatings. this makes them ideal for studying the effect of the presence of ancillary mineral phases on the surface properties of the dominant clay minerals in clay solids. kaolin clays are deposits rich in kaolin-group minerals that mainly include kaolinite, halloysite, dickite and nacrite, with kaolinite being the most common (cygan & tazaki, 2014). kaolinite is a dioctahedral clay mineral of rather large particle diameter (up to several tens of micrometers), and accordingly, low specific surface area (ssa) and cation ex­ change capacity (cec) (ma & eggleton, 1999; ber­ gaya et al., 2006). kaolinite usually exhibits low or no per­ manent charges on the siloxane surfaces on account of the limited isomorphic substitution in its structure (moore & reynolds, 1997; bailey, 1991), which makes the con­ tribution of the amphoteric edges to their surface properties significant (ma & eggleton, 1999). the main objective of this study was to investigate the surface properties and the electrokinetic behaviour of kaolin samples obtained from different pegmatite and granite de­ posits worldwide. in particular, this study aims to clarify the influence of ancillary minerals associated with the prevail­ ing kaolinite mineral on the surface properties and the reac­ tivity of kaolin samples. the results obtained should com­ plement existing knowledge on the surface properties of kaolin clays. 2. methodology 2.1. source of kaolin clays five kaolin samples derived from pegmatite and granite de­ posits, with various content and amounts of ancillary miner­ als, were investigated (table 1). sample s1 (mamoes, equa­ dor) originates from a pegmatite, but it is not clear whether it is an alteration of feldspar by hydrothermal fluids, or by meteoric water. sample s2 (jacu, brazil) originates from a pegmatite but its origin is not yet determined. samples s3 and s5 (almas, parelhas, brazil) were obtained from a peg­ matite, and they were probably formed as a supergene al­ teration. sample s4 was obtained from sierra leone and formed as an alteration of granite. ivanić et al.: mineralogy, surface properties and electrokinetic behaviour of kaolin clays derived from naturally occurring pegmatite and granite deposits geologia croatica 141 in order to remove the coarser fractions, samples were dispersed in deionized water for 2 weeks and regularly stirred. prior to separation, kaolin clay dispersions were sonicated in an ultrasonic bath, left to settle for 2 minutes after which the upper 5 cm of the suspension was separated from the residue using a pipette. the suspension was used for par­ ticle size measurement and then freeze-dried (freezone 2.5, labconco, usa) for further measurements. separated kaolin samples were not subjected to any kind of chemical treat­ ment. 2.2. laboratory methods and techniques the mineral composition was determined by the x-ray dif­ fraction method using an x-ray powder diffractometer phil­ ips pw 3040/60 x’pert pro (panalytical, b.v., the neth­ erlands) with cu-tube accelerated by 40 kv and a current of 40 ma. the x-ray diffraction patterns were analyzed using highscore plus software (panalytical, 2004) and the mineral components were identified according to the jcpds powder diffraction files. clay minerals were identified according to their basal peaks after standard preparation procedures and sample treatments proposed by starkey et al. (1984). the diffraction peaks on the xrd patterns were coded as fol­ lows: k – kaolinite, s – smectite, m – muscovite, f – feld­ spars, q – quartz. the cation exchange capacity (cec) was determined using an ammonia selective electrode based on the method described by busenberg & clemency (1973). the specific surface area measurements (ssa) were performed by a single-point nitrogen adsorption, using a flowsorb ii 2300 instrument (micromeritics, usa). particle size was determined using a laser diffraction particle size analyzer ls 13 320 (beckman coulter, usa). electrophoretic mobility was measured using a zetasizer nano zs (malvern, uk). the software automatically calculated the zeta-potential from electrophoretic mobility using the henry equation. samples were prepared in a 1 ́ 10–3 mol dm–3 nacl solution and the ph range (2–10) was adjusted with a 0.1 mol dm–3 solution of hcl and naoh. 3. results and discussion 3.1. mineralogy and surface properties of kaolin clay samples according to xrd analyses, kaolinite was identified as a primary mineral phase in all the investigated samples (fig. 1). however, a significant difference in the content of ancillary minerals in the kaolin clays was determined. the associated minor mineral phases in samples s1 and s2 were muscovite and quartz, in sample s3 muscovite, quartz and feldspars while in samples s4 and s5 muscovite, quartz, feldspars and smectites occurred (table 1). the presence of smectite clays in samples s4 and s5 could be the result of similar weather­ ing processes. however, the x-ray diffraction results (fig. 1) show different patterns that could arise from the origin of samples s4 and s5. smectite in sample s4 was developed figure 1: xrd patterns of the investigated kaolin clays. table 2: specific surface area (ssa), cation exchange capacity (cec) and the mean size (mz) of the investigated kaolin clay samples. sample ssa (m2g–1) cec (cmol+kg–1) mz (µm) s1 6.9 3.4 28.0 s2 9.6 4.2 20.5 s3 14.4 7.6 17.8 s4 19.4 8.5 16.7 s5 18.1 15.5 18.8 through the weathering of finer grains of feldspar from a granite rock in a tropical climate in sierra leone, while that in sample s5 derived from a pegmatite. the grain size distribution spectra of the kaolin samples are shown in figure 2. all spectra exhibit a similar granulom­ etric distribution pattern, with a mean particle size ranging from 17 to 28 µm (table 2). the relatively large particle size of the kaolin clays indicates the presence of kaolinite “book­ lets”, the micron-sized morphological structures built up of numerous platelets that are typical for the kaolinite mineral (bergaya et al., 2006; balan et al., 2014). the appear­ ance of these morphological features was confirmed by the fe-sem images displayed in figure 3a-d. these are charac­ terized by stacked pseudo-hexagonal platelets with diameters geologia croatica 68/2geologia croatica 142 the cec and ssa of kaolin clay samples are shown in figure 4. the obtained cec and ssa values were in the range of 3.4–15.5 cmol+kg–1 and 6.9–19.4 m2g–1, respec­ tively (table 2). the results obtained have shown that kaolin solids with a greater content of ancillary smectite (samples s4 and s5) displayed higher cec and ssa values. smectites are characterized by high cec and external ssa values, up to 120 cmol+kg–1 and 78 m2g–1, respectively (bergaya et al., 2006; sondi et al., 1996a). thus, the high ssa values of 19.4 and 18.1 m2g–1 obtained for samples s4 and s5, should be ascribed to their presence in the investigated kao­ lin solids. smectites are also characterized by small particle diameters (zhuang & yu, 2002) and their presence in samples should lower the mean particle size of the kaolin samples. indeed, the obtained mean particle size for samples s4 and s5 is in accordance with these observations (table 2). a relatively high ssa of 14.4 m2g–1 was also measured for sample s3. since this sample did not contain smectites, rel­ atively high ssa values could be the consequence of the smaller grain size of the kaolin clay samples (17.8 µm). the cec of 15.5 cmol+kg–1 in sample s5, was the high­ est of all the investigated samples, which is in accordance with the presence of smectites in this sample. a similar con­ clusion was proposed by ma & eggleton (1999) who figure 2: particle size distribution of the investigated kaolin clays. figure 3: fe-sem photomicrographs of kaolinite in the kaolin clay samples: s1 (a), s2 (b, c), s3 (d), s4 (e) and s5 (f). 0.1–1.5 µm and a thickness in the range of approximately 30– 100 nm. the stacking of platelets produced “booklets” of sev­ eral tens of micrometres which is especially evident in sample s2 where a high degree of stacking led to the exposure of edge surfaces (fig. 3b,c). ivanić et al.: mineralogy, surface properties and electrokinetic behaviour of kaolin clays derived from naturally occurring pegmatite and granite deposits geologia croatica 143 figure 4: the specific surface area (ssa) and the cation exchange capacity (cec) of the investigated samples. figure 5: electrophoretic mobility and zeta-potential of the kaolin clay samples dispersed in 1x10–3 mol dm–3 nacl solution, as a function of ph. discovered that the presence of smectites coincided with the high cec occurring in some kaolin clays. however, the cec in sample s4, which also contains ancillary smectites, was not as high as expected (8.5 cmol+kg–1) probably due to di­ lution with other minerals of low surface reactivity (quartz, muscovite and feldspars). despite their common origin, samples s3 and s5 exhibit different compositions of ancillary minerals (table 1), with the main variation being the presence of smectite in sample s5, and consequently the disparity in cec values, 7.6 cmol+kg–1 (s3) and 15 cmol+kg–1 (s5). the absence of smectites and the presence of quartz and muscovite in samples s1 and s2 resulted in the lowest cec and ssa values of all the investigated samples. these results were in accordance with the surface properties of the pure kaolinite clay minerals that usually exhibit relatively large particle diameters and low ssa and cec values (van ol­ phen, 1977; ma & eggleton, 1999; wilkinson & reinhardt, 2005; bergaya et al., 2006). accordingly, the surface properties of ancillary minerals in these kaolin samples have not rescinded the native surface properties of the dominant kaolinite mineral. the presence of smectites, even in small amounts, significantly changes surface prop­ erties and raises the cec and ssa values of the kaolin clay samples. in our previous study (sondi et al., 1996a) it was shown that a natural clay mixture of illite (30%), chlorite (55%) and montmorillonite (15%) exhibited the surface properties of montmorillonite, regardless its relatively low content in the clay fraction. 3.2. electrokinetic behaviour of kaolin clay samples the epm and zeta-potential curves as a function of ph for the kaolin clay samples are displayed in figure 5. for most samples, negative epm values were measured across the whole ph range investigated. a significant decrease of neg­ ative epm and zeta-potential values with decreasing ph was also determined. this effect was more pronounced in sam­ ples s1-s3 than in samples s4 and s5. the strongest effect of ph on epm was observed in sample s2 where an isoelec­ tric point (iep) was reached at ph~2.5. it leaves no doubt that the structural and the morphological properties of the kaolinite mineral and the presence of ancillary smectite gov­ ern the electrokinetic properties of the investigated kaolin clay samples. the kaolinite mineral usually appears in the form of stacked platelets where the edges represent a larger fraction of the total surface area (bergaya et al., 2006). these structures limit the accessibility of the basal siloxane sur­ faces and expose the amphoteric edge surfaces to the aque­ ous solution. these surfaces are structurally and chemically heterogeneous and characterized by different charging mech­ anisms. as a consequence, their ratio will affect the elec­ trokinetic behaviour of the bulk sample (sondi et al., 1997b; tombácz & szekeres, 2006). the morphology of kaolinite minerals investigated in this study was also characterized by the exposed edge sur­ faces (fig. 3b,c). therefore, a significant decrease in their negative charge under acidic conditions is expected, since a part of their charge originates from the amphoteric edge sites which are protonized under low ph conditions. a decrease in epm with the decrease in ph was more pronounced for kaolin samples that contain kaolinite characterized by more abundant edge surfaces. the obtained epm values for sam­ ples s1-s3 were in accordance with the results previously obtained by sondi et al. (1997b) who investigated a pure kaolinite solid. samples s4 and s5 showed significantly smaller changes of epm values over the investigated ph range (fig. 5). this could be explained by the presence of ancillary smectites in these solids. previous investigations have shown that the portion of edge surfaces in smectites is negligible in com­ parison to the basal siloxane surfaces (sondi et al., 1997b; sondi & pravdić, 2002; wan & tokunaga, 2002). the permanent negative surface charge of smectites exposed at the basal siloxane surfaces is ph independent and de­ scribed by the constant basal surface charge (cbsc) model (sondi et al., 1997b; ma & eggleton, 1999). there­ fore, charge occurring at the basal surfaces is responsible for the total charge of the smectites while the edge charges are less pronounced. in comparison with samples s1-s3, for geologia croatica 68/2geologia croatica 144 which epm was ph-dependent and determined by the pres­ ence of the amphoteric edge surfaces, samples s4 and s5 exhibited almost no ph-dependency. the prevalence of the negative siloxane surfaces of ancillary smectites over the to­ tal surface charge of kaolinite show their overwhelming in­ fluence on the electrokinetic behavior of kaolin clays. this study undoubtedly demonstrates that the presence of ancil­ lary smectites hindered the surface charge properties of the prevailing kaolinite mineral in the kaolin clays. 4. conclusion this study describes the influence of ancillary minerals on the surface properties (ssa, cec, epm) of kaolin solids of igneous origin. it was shown that the presence of ancillary minerals with low surface reactivity (quartz, feldspars, and muscovite) exhibit no effect on the surface properties of the prevailing kaolinite and such clays revealed the same behav­ iour as a pure kaolinite mineral. the presence of ancillary smectite minerals in kaolin clay samples resulted in a significant increase of their cec and ssa values. in addition, their presence changed the ra­ tio between the basal siloxane and the amphoteric edge sur­ faces of kaolin clays resulting in their limited response to the changes in the epm with the variation of ph. the results of this study imply that kaolin clays will re­ tain the behaviour of the prevailing kaolinite mineral when they contain ancillary minerals characterized by low surface reactivity. in contrast, the kaolinite surface properties will be rescinded by surface properties of ancillary smectites characterized by higher surface reactivity, even when they are present in trace amounts. acknowledgment this research was supported by the croatian science foun­ dation (grant no. 2504) and by the ministry of science, education and sports of the republic of croatia (grant no. 119-0000000-1158). the author gratefully acknowledges the help of dr. andre botha with the fe-sem analyses. references bailey, s.w. (1980): summary of recommendations of aipea.– clays clay miner., 28, 73–78. doi: 10.1346/ccmn.1980.0280114 bailey, s.w. (1991): hydrous phyllosilicates (exclusive of micas).– reviews in mineralogy msa, 19, 725 p. doi: 10.1016/0037-0738 (89)90093-6 balan, e., calas, g. & bish, d. (2014): kaolin-group minerals: from hydrogen-bonded layers to environmental recorders.– ele­ ments, 10, 183–188. doi: 10.2113/gselements.10.3.183 bergaya, f., lagaly, g. & vayer, m. (2006): cation and anion exchange.– in: bergaya, f., theng, b.k.g. & lagaly, g. (eds.): handbook of clay science, developments in clay science, vol. 1. elsevier, 979–1001. doi: 10.1016/s1572-4352(05)01036-6 busenberg, e. & clemency, c.v. (1973): determination of the cation exchange capacity of clays and soils using an ammonia electrode.– clays clay miner., 21, 213–217. chekli, l., phuntsho, s., roy, m. & shon, h.k. (2013): char­ acterization of fe-oxide nanoparticles coated with humic acid and suwannee river natural organic matter.– sci. tot. env., 461, 19–27. doi: 10.1016/j.scitotenv.2013.04.083 cygan, r.t. & tazaki, k. (2014): interactions of kaolin minerals in the environment.– elements, 10, 195–200. doi:10.2113/gsele­ ments.10.3.195 ferris, a.p. & jepson, w.b.j. (1975): the exchange capacities of kaolinite and the preparation of homoionic clays.– colloid interface sci., 51, 245–259. doi:10.1016/0021-9797(75)90110-1 grim, r.e. (1968): clay mineralogy.– mcgraw hill, new york, 596 p. herrington, t.m., clarke, a.q. & watts, j.c. (1992): the sur­ face charge of kaolin.– colloid. surface., 68, 161–169. doi: 10.1016/0166-6622(92)80200-l james, a.e. & williams, d.j.a. (1982): particle interactions and rheological effects in kaolinite suspensions.– adv. colloid interface sci., 17, 219–232. doi:10.1016/0001-8686(82)80021-3 jepson, w.b. (1988): structural iron in kaolinites and in associated an­ cillary minerals.– in: stucki, j.w., goodman, b.a. & schw­ ertmann, u. (eds.): iron in soils and clay minerals, nato asi, series c: mathematical and physical sciences, vol. 217, d. reidel publishing company, holland, 467–536. ma, c. & eggleton, r.a. (1999): cation exchange capacity of kao­ linite.– clays clay miner., 47, 174–180. doi: 10.1346/cc­ mn.1999.0470207 moore, d.m. & reynolds, r.c.jr. (1997): x-ray diffraction and the identification and analysis of clay minerals.– oxford univer­ sity press, oxford, 378 p. newman, a.c.d. (1987): chemistry of clays and clay minerals, min­ eralogical society monograph 6.– longman scientific & technical, 480 p. sondi, i., bišćan, j. & pravdić, v. (1996a): electrokinetics of pure clay minerals revisited.– j. colloid interface sci., 178, 514–522. doi: 10.1006/jcis.1996.0146 sondi, i. & pravdić, v. (1996b): electrokinetics of natural and me­ chanically modified ripidolite and beidellite clays.– j. colloid in­ terface sci., 181, 463–469. doi:10.1006/jcis.1996.0403 sondi, i., stubičar, m. & pravdić, v. (1997a): surface proper­ ties of ripidolite and beidellite clays modified by high-energy ball milling.– colloid. surface. a, 127, 141–149. doi: 10.1016/s09277757(96)03893-9 sondi, i., milat, o. & pravdić, v. (1997b): electrokinetic poten­ tials of clay surfaces modified by polymers.– j. colloid interface sci., 189, 66–73. doi: 10.1006/jcis.1996.4753 sondi, i. & pravdić, v. (2002): elektrokinetics of clay mineral sur­ faces.– in: encyclopedia of surface and colloid science, marcel dekker, usa, 1887–1893. sposito, g. (1984): the surface chemistry of soils.– oxford univer­ sity press, new york, 234 p. starkey, h.c., blackmon, p.d. & hauff, p.l. (1984): the rou­ tine mineralogical analysis of clay-bearing samples.– usgs bul­ letin, 1563, 1–32. theng, b.k.g. & yuan, g. (2008): nanoparticles in the soil environ­ ment.– elements, 4, 395–399. doi: 10.2113/gselements.4.6.395 tombácz, e. & szekeres, m. (2004): colloidal behaviour of aque­ ous montmorillonite suspensions: the specific role of ph in the pres­ ence of indifferent electrolytes.– appl. clay sci., 27, 75–94. doi: 10.1016/j.clay.2004.01.001 tombácz, e. & szekeres, m. (2006): surface charge heterogeneity of kaolinite in aqueous suspension in comparison with montmorillo­ nite.– appl. clay sci., 34, 105–124. doi: 10.1016/j.clay.2006.05.009 ivanić et al.: mineralogy, surface properties and electrokinetic behaviour of kaolin clays derived from naturally occurring pegmatite and granite deposits geologia croatica 145 van olphen, h. (1951): rheological phenomena of clay sols in con­ nection with the charge distribution on the micelles.– discuss. faraday soc., 11, 82–84. doi: 10.1039/df9511100082 van olphen, h. (1977): an introduction to clay colloid chemistry.– john wiley & sons, usa, 318 p. vdović, n., jurina, i., škapin, s. & sondi, i. (2010): the surface properties of clay minerals modified by intensive dry milling – revis­ ited.– appl. clay sci., 48, 575–580. doi: 10.1016/j.clay.2010.03.006 wan, j. & tokunaga, t.k. (2002): partitioning of clay colloids at air-water interfaces.– j. colloid interface. sci., 247, 54–61. doi: 10.1006/jcis.2001.8132 wilkinson, k.j. & reinhardt, a. (2005): contrasting role of nat­ ural organic matter on colloidal stabilization and flocculation in freshwaters.– in: droppo, i., leppard, g.g., liss, s.n. & milligan, t.g. (eds.): flocculation in natural and engineered environmental systems, crc press, 438 p. zhou, z. & gunter, w.d. (1992): the nature of the surface charge of kaolinite.– clays clay miner., 40, 365–368. doi: 10.1346/cc­ mn.1992.0400320 zhuang, j. & yu, g.-r. (2002): effects of surface coatings on elec­ trochemical properties and contaminant sorption of clay minerals.– chemosphere, 49, 619–628. doi: 10.1016/s0045-6535(02)00332-6 manuscript received december 10, 2014 revised manuscript accepted march 27, 2015 available online june 16, 2015 2020 | 73/1 | 49– 58 | 9 figs. | 2 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction shale gas is a type of unconventional natural gas where the source and reservoir both occur in the same shale layer (ju et al., 2014). since the success of the commercial development of shale oil and gas in north america, the exploration and development of shale gas has sprung up all over the world (table 1; warlick, 2006; hill & nelson, 2000; wang et al., 2017). organic-rich shale layers can be effective reservoirs for shale gas accumulation under certain geological conditions (curtis, 2002; durham, 2005; guo et al., 2014). the lower palaeozoic shale in the sichu an basin is one main developmental layer of shale oil and gas in china (wang, 2010; guo et al., 2014; jin et al., 2016). some breakthroughs have been made on shale gas exploration in this area, gaining the attention of geologists and field experts. shale gas layers in the sichuan basin are mainly located in the cambrian niutitang and the silurian longmaxi formations (wang, 2016). these shales were deposited in a similar sedimentary environment to the united states marine shale which is mostly a deep-water shelf facies and transgressive systems tract (ulmishe & klemme, 1990; loucks & ruppel, stephen, geological conditions and gas-bearing evaluation of the niutitang formation shale in the xixiang–zhenba area, china qing xie1*,2, feng xu1**,2, ning wang1***,2 and zhen yang3 1 shaanxi mineral resources and geological survey, xi’an 710068, p.r.china; (*e-mail corresponding author: xieqingsunny@163.com; **e-mail: xufeng2@163.com; ***e-mail: 441090192@qq.com) 2 shaanxi institute of geological survey, xi’an 710054, p.r.china; 3 ministry of natural resource, the first institute of photogrammetry and remote sensing, mnr xi’an 710054, p.r.china; (e-mail: yangzhen6@qq.com) doi: 10.4154/gc.2020.05 abstract black carbonaceous shale of the niutitang formation in the xixiang–zhenba area was found to be well developed and abundant in high-quality shale gas. however, few studies have been conducted in this area, and its reservoir-forming conditions are not clear. this study aims to analyse source rocks, reservoir characteristics and storage conditions of the niutitang formation shale in the xixiang–zhenba area using field investigations, drilling and logging, supplemented with laboratory experiments. results of this study shows that the niutitang formation shale is deeply buried at 1500–4500 m and is mainly 10-110 m thick. the shale is widely distributed, thicker in the west, thinner in the east and is a highly mature organic rich source rock with kerogen type i and ii. the shale stratum features a high content of brittle minerals, many natural cracks, and a low content of clay minerals which are mainly illite, followed by a mixed layer of illite and smectite. the shale reservoir is characterized by low porosity and permeability. in addition, the lithology is dense and acts as a good seal in this area while it has a high adsorption capacity and high gas-bearing potential. overall, within the study area, the western, central, and southern parts have good structural preservation conditions. the niutitang formation in the study area shows excellent organic matter characteristics for shale gas generation as well as good geological conditions for shale gas accumulation. 2007; wang et al., 2015). the lower cambrian shale is one source rock of the sichuan basin and its surrounding areas. this shale layer is characterized by its large thickness, wide distribution, high level of maturity, and a great potential for gas generation (li et al., 2009; wu et al., 2014). the cambrian niutitang formation in the upper yangtze area of south china has a high organic matter content and high maturity, which lays a material foundation for formation of shale gas reservoirs (hu et al, 2014). previous studies on the sichuan basin have yielded various results regarding the shale distribution and hydrocarbon-generating potential of the organic matter. according to the results, it is believed that the lower palaeozoic marine shale satisfies the geological conditions for shale gas accumulation in the sichuan basin and its surrounding areas, although it was previously thought to be inferior to the paleozoic marine shale in the united states (table 1; rach, 2004; jarvie, 2007; warlick, 2006; berman, 2009; li et al., 2013; wang et al., 2015). many studies have been conducted on the niutitang formation shale in the sichuan basin (zhou et al., 1999; mao et al., 2006; pu et al., 2010; wu et al., 2014; shen et al., 2017). howarticle history: manuscript received april 23, 2019 revised manuscript accepted february 06, 2020 available online february 29, 2020 keywords: shale gas reservoir, accumulation conditions, niutitang formation, xixiang–zhenba area, china table 1. comparison of main geological features of gas-bearing shale between the shale gas basin in the united states and the sichuan basin in china. basin name of the shale thickness (m) total organic carbon (%) buried depth (m) organic matter type vitrinite reflectance (%) tectonic movement fort worth barnett 61–91 1.00–4.50 1981–2591 ii 1.10–1.40 simple michigan antrim 48.80 0.20–20.00 183–671 i 0.40–1.60 simple san juan lewis 152–579 0.50–2.50 91–1829 ii 1.60–1.88 simple sichuan basin longmaxi formation 30–120 1.88–4.36 1600–8000 i 2.60–3.60 complexity niutitang formation 20–200 1.50–5.70 2500–10000 i 3.00–4.20 complexity china geological survey standard >15 >2.00 500–4500 0.50–3.50 g eo lo gi a c ro at ic a geologia croatica 73/150 ever, few have been conducted in the xixiang–zhenba area (the surrounding area of the sichuan basin) (fig 1; chen et al., 2018). shale gas accumulation conditions and gas-bearing properties in this area are unclear. in 2014–2016, the china geological survey discovered the shale gas reservoir of the cambrian niutitang formation in well x-1, panjiapo village, yongle town, zhenba county for the first time. the on-site analytical gas content is 0.58–2.91m3/t, averaged as 1.79 m3/t. since then, this area has attracted more and more attention. with the niutitang formation shale in the xixiang–zhenba area as the main object of this study, the aims were to evaluate the shale source rock, reservoir characteristics, and preservation conditions. the distribution, thickness, buried depth of the shale were measured; organic matter abundance and reservoir characteristics of the source rock were studied and the gas-bearing properties were evaluated through field excavation, logging, and later lab experiments. results and conclusions of this study provide a good foundation for future research and development in the study area. 2. geological background overview the study area is located on the northern margin of the yangtze block in south china (fig. 1). geologically, the evolution of the yangtze block can be divided into three stages over 2.5 billion years of history, from the pre-nanhua period, through the nanhua period to the middle triassic (caprock deposit) period, and the late triassic period (huang & shen, 2015). the basement consists of the neoarchean–palaeoproterozoic gneiss, mixed rocks, and metamorphic volcanic-sedimentary rocks of the late middle proterozoic to the early neoproterozoic and intrusive complexes during the same period. the basement had been covered by the cap rock deposits of the platform since the nanhua period. it represents stable deposition in the epicontinental and marginal seas to the inland basin transformation, accompanied by the formation, reduction and subduction of the shangdan ocean to the north (li, 2010 & wu et al., 2013). the collision between the north and south china plates caused intermittent overall uplift and erosion of the yangtze block, resulting in the loss of upper cambrian, upper–middle silurian, devonian, and carboniferous strata. the tectonic grid was mainly formed by the intraplate/land overlap a-type subduction in the indosinian– yanshan period. it was also the result of long-term interaction between the qinling orogenic belt, the yangtze block, and the songpan–ganzi orogenic belt (fig. 1). the lower cambrian niutitang formation in the study area is located in the northeastern part of the outer margin of the sichuan basin, around the basement uplift of hannan–micang mountain. its administrative division is mainly located in zhenba county, xixiang county and parts of nanzheng county. 3. materials and methods 3.1. samples over 100 outcrop samples were collected at 8 sampling locations (sampling sections) in the niutitang formation. sampling locations were located in well-exposed areas, mainly in guanyin’an, jiandongzigou and zhujiaba (fig. 1). fresh and representative shale samples were selected for experimental analyses. samples collected at outcrop sections were generally 3×6×9 cm in size. the total organic carbon (toc) samples were collected every 3-5 m in the shale, and the remaining samples were collected every 10-40 m. more than 70 thin-sections were analysed, 50 samples were prepared for scanning electron microscope analysis and 4 samples were used for isothermal adsorption experiments. 3.2. methods the total organic carbon was determined using a total organic carbon analyzer (multi-n/c3100-za310j). the total hydrocarfigure 1. geodetic location map of the study area (gong et al., 2010). g eologia c roatica xie et al.: geological conditions and gas-bearing evaluation of the niutitang formation shale in the xixiang–zhenba area, china 51 bon is the bulk composition of saturated hydrocarbon and aromatic hydrocarbon in the chloroform pitch “a”(eom). it was obtained by chloroform asphalt extraction using the soxhlet extraction method. the rock samples were pulverized into powder with a particle size of less than 0.09 mm, and then continuously steamed with chloroform under boiling temperatures (generally 80° c) to extract the soluble organic matter in the rock. the vitrinite reflectance (ro) and maximum temperature of the rock eval pyrolysis (tmax) were used to evaluate organic matter maturity. ro was detected using a microscope photometer (mpv-3), and tmax was measured using a rock pyrolysis analyzer (oge-vi). the kerogen type of the niutitang formation shale was determined using the kerogen ti index (cao, 1985), kerogen carbon isotope ratio and h/c and o/c atomic ratios of the kerogen. the ti = (sapropelite, %×100+ exinite ,%×50-vitrinite, %×75 inertinite, %×100)/100) and kerogen carbon isotope were detected by using multi-collector inductively-coupled plasma mass spectrometry(mc-icp-ms), and the organic elements in the kerogen were observed using the element analyzer (flash-irms) and stable isotope mass spectrometer (delta v advantage). the mineralogical characterization of shale samples was carried out using an x-ray diffractometer (xrd, d/max-2500v). to obtain the microscopic pore characteristics, shale samples were observed using scanning electron microscopy (sem, jib-4500) and an electron probe micro-analyzer (epma, japan-jeoljxa-8230). taking well x-1 as an example, after obtaining the on-site analytical gas content, the residual gas content was measured in the laboratory. in addition, the lost gas content was calculated by linear regression, with the total gas content being obtained by summing these three components. this procedure was carried out by the china geological survey in 2014. the toc content of the shale was estimated from the positive correlation between the total gas content and the toc content (reedr et al., 2007). an isothermal adsorption experiment was used to simulate the adsorption process of the shale using an isotherm instrument (gai100-za306m). the relationship model of the adsorption gas content with regard to pressure and temperature was established and then gas content was obtained. this can also be used to veri fy the relationship between the amount of adsorption and total organic carbon. the methodology of the isothermal adsorption experiment was as follows. the shale samples were pulverized and heated to remove the adsorbed natural gas. they were then placed in a sealed container and the pressure was continuously increased under a constant temperature (25 ℃). the amount of the adsorbed natural gas was measured and the measurements were fitted to the langmuir equation to form an isothermal adsorption curve. 4. results and interpretation 4.1. sedimentary environment during the early palaeozoic sea level rose rapidly, whereby the sichuan basin and surrounding areas were generally open continental shelf environments. the west side of these areas was dominated by uplift of the chuanzhong, and motianling island was located to the north. the distribution of the sedimentary facies in the southeast of the areas was the shore facies–shallowwater shelf facies–deep-water shelf facies (fig. 2). water depth around the ancient land increased and the nearshore coastal zone was less preserved due to the transgression of the niutitang period. during the transgression, shallow-water shelf facies prograded in the middle and late stages of the early palaeozoic.the micang mountain strata, in the west of the study area (fig. 1), evolved from the late sinian-chinese stratigraphic age-dengying period to the early cambrian niutitang period and were represented by continuous deposition. this led to the integrated contact of the dengying formation with the niutitang formation (fig. 3). with expansion of the marine transgression from the southeast to the northwest, the niutitang formation overlapped westward. due to gradual uplift the formation is absent in the northwest of the hannan uplift (fig. 1), resulting in the unconformable contact of the shipai formation over the dengying formation. in the study area two major sedimentary subfacies developed; the deep-water shelf subfacies and the shallowwater shelf subfacies (fig. 2). the boundary of these two subfacies is located to the west of zhenba county and east of bashan forest farm (fig. 1) and runs approximately north– south. the shallow-water shelf was developed in the east, and the deep-water shelf to the west of the boundary. the shale thickness and organic matter content of the deep-water shelf are figure 2. sedimentary facies of the sichuan basin and the niutitang formation study area (mu et al., 2011). g eo lo gi a c ro at ic a geologia croatica 73/152 figure 3. typical litho-stratigraphic section and sedimentary facies of xixiang area and its substratum. g eologia c roatica xie et al.: geological conditions and gas-bearing evaluation of the niutitang formation shale in the xixiang–zhenba area, china 53 higher than those of the shallow-water shelf, which is also consistent with the results of the sedimentary facies distribution (dong et al., 2010; wang et al., 2012; guo et al., 2014). 4.2. source rock characteristics 4.2.1. shale distribution characteristics lower palaeozoic marine shale developed in southern china has a good material basis for the formation of large oil and gas fields (fig. 3). it is generally believed that the lower palaeozoic marine shale is the most important source rock in south china and has a good shale gas exploration prospect (zhou et al., 1999; mao et al., 2006; zhang et al., 2008; li et al., 2013; shen et al., 2017). the black shale of the niutitang formation in the study area is mainly located at dahe town in xixiang county, gaoqiao village, xiaoyangba, ping’an chang and xingzi mountain areas of zhenba county, fucheng town and the town of beiba in nanzheng county (fig. 1). the niutitang formation is mainly composed of black carbonaceous shale, silty shale, and black carbonaceous siliceous shale with siltstone and marl. the shale and siltstone form very fine horizontal bedding. the distribution of the dust-like pyrite is often along the bedding plane and pyrite nodules are also very common. the shale thickness is mainly 10-110m, from south to north, and its thickness increases from east to west. high quality source rocks are mainly distributed in the fucheng and dahe towns in the west, with a thickness of 80-100m (fig. 1). the carbonaceous shale of the niutitang formation reduces from east to west, and it reflected the shallowing characteristics of the water level, which was also consistent with the characteristics of the sedimentary facies. 4.2.2. geochemical characteristics of organic matter 4.2.2.1. abundance of organic matter abundance of organic matter is one of the most important indicators for evaluating shale source rocks. the total organic carbon and total hydrocarbon content (saturated hydrocarbons and aromatics content) are common indicators for evaluating the abundance of shale organic matter (burnaman & shelton, 2009). results from more than 60 outcrop samples, show the toc of the niutitang formation ranges from 0.25% to 9.45%, with an average of 2.93%. the toc of the western shale area is generally figure 4. van krevelen diagram of the samples. figure 5. the mineral composition and clay content of the samples. g eo lo gi a c ro at ic a geologia croatica 73/154 greater than 1% (mostly between 2% and 6.5%), with an average of 3.66%. the toc of 69.81% samples ranges from 2% to 4%, indicating organic-rich shales. the content of saturated hydrocarbons and aromatics in extracts from the shale ranges from 12.63% to 55.90%, with an average of 31.54%, the total hydrocarbon content is mainly 100-1500ppm. in general, the shale of the niutitang formation is rich in organic matter, which provides a good material basis for a shale gas reservoir. 4.2.2.2. type of organic matter the shale kerogen contains a large amount of the macerals of the sapropelite group (more than 93%), and a small amount of macerals of the vitrinite group. the kerogen ti index method (ti > 80, kerogen type i) reveal that the shale kerogen of the niutitang formation is of type i. the shale kerogen carbon isotope value d13c ranges from -33.5 to -33.06‰. the shale kerogen type is mainly type i. the kerogen h/c and o/c atomic ratios range from 0.46 to1.48 (average 1.07) and from 0.06 to 0.33 (average 0.12), respectively. the shale kerogen type is mainly type i and ii (van krevelen diagram, fig. 4). based on all the results obtained, the kerogen of the niutitang formation shale is of type i and ii, types that are favourable for hydrocarbon generation. 4.2.2.3. maturity of organic matter thermal maturity is the basis for evaluating the hydrocarbon generation potential of the source rocks. maturity is mainly evalu ated by vitrinite reflectance (ro) and the maximum temperature of the rock eval pyrolysis (tmax). the ro is between 2.14% and 2.84%, with an average of 2.51%, so generally greater than 2%. the organic matter is mainly in the over mature stage of thermal alteration. the tmax of the kerogen is mainly between 486°c and 569°c, with a maximum of 584°c indicating a high-over mature stage. based on ro and tmax, the maturity of the organic matter is in the high-over maturity stage. 4.3. reservoir characteristics according to geochemical characteristics, the niutitang formation shale is a high quality source rock, but whether it is a good reservoir is also very important for shale gas reservoir formation (velić et al., 2012). based on the test in well x-1, the gas content of the niutitang formation shale is high, and there are clearly reservoir conditions and some exploration potential indicated. 4.3.1. rock mineralogical characteristics mineral x-ray diffraction analysis of the black shale samples shows that the black shale consisted mainly of quartz, clay, feldspar, and a small amount of pyrite, siderite and carbonate minerals. the quartz content is greatest from 30% to 54%, (average 38%); clay content ranges from 9% to 38%, (average 25%); with 13% to 38% feldspar (average 27%, of which k-feldspar is 0%–7%, (average 4%); plagioclase 12%–34%, (average 23%)). pyrite content varies from 0% to 6%, (average 3%); and the siderite content is the smallest, from 0% to 2%, (average 1%) (fig. 5a). the content of the brittle minerals is high, meaning that it can easily be broken by external force to form cracks. the possibility of shale fracturing is beneficial to the exploitation of the shale gas (liu, 2012). the clay minerals of the shale samples are mainly illite, followed by a mixed layer of illite and smectite and a small amount of smectite and chlorite (table 2, fig. 5b). the illite content vari es table 2. clay mineral relative content test results for the samples. number clay mineral content (%) mixed layer of illite and smectite content (%) smectite illite kaolinite chlorite illite/ smectite chlorite/ smectite smectite layer illite layer pm02-1 10 80 0 4 6 0 65 35 pm02-2 0 55 0 8 37 0 10 90 pm02-3 0 82 0 0 18 0 10 90 pm02-24 0 82 0 0 18 0 10 90 pm03-1 0 47 0 0 53 0 10 90 pm03-2 0 45 0 15 40 0 10 90 pm08-2 0 93 0 0 7 0 5 95 pm10-1 0 71 4 5 20 0 65 35 pm10-2 0 54 5 9 32 0 10 90 pm10-3 0 67 6 10 17 0 10 90 pm10-4 0 70 4 10 16 0 10 90 pm10-5 0 64 6 10 20 0 10 90 pm10-6 0 66 4 9 21 0 10 90 pm10-7 0 61 7 10 22 0 10 90 pm10-8 0 74 4 10 12 0 10 90 pm10-9 0 63 5 7 25 0 10 90 pm10-10 0 70 6 11 13 0 10 90 figure 6. microstructural features of the samples. (a) dissolution pores of calcite/dolomite particles; (b) casting-mold pores formed by the dissolution of pyrite and the residual pyrite particles; (c) linear pores; (d) intergranular pores between clay mineral particles; (e) pores between the pyrite crystals; (f ) microfractures; (g) organic pores; (h) oriented quartz particles. g eologia c roatica xie et al.: geological conditions and gas-bearing evaluation of the niutitang formation shale in the xixiang–zhenba area, china 55 between 45% and 93%, with an average of 69.1%; the content of mixed layer of illite and smectite is between 6% and 53%, with an average of 25.6%; and the content of the chlorite and smectite is 5.3%. the mixed layer illite and smectite is mainly the illite layer, which accounts for 35% to 95%, with an average of 82.9%. schettler et al. (1990) showed that the adsorbed methane in the shale was mainly distributed on the surface of the clay mineral illite and then in kerogen. lu et al. (1995) determined that the illite in clay minerals was particularly important for the adsorption of shale gas in shales with low organic carbon content. the higher content of illite in the shale of the niutitang formation is beneficial for improving the adsorption performance of the shale and the preservation of the adsorbed gas (wang et al., 2017). 4.3.2. reservoir pore space type and pore structure characteristics the results of sem and epma have shown that the pores and microcracks of the niutitang formation shale are relatively well developed. the pore types include the intragranular pores, intergranular pores and organic pores, providing good spaces for shale gas accumulation (jarvie et al., 2007; yu, 2013; shao et al., 2019). the intragranular pores developed inside the particles or crystals. most of them were triangular/quadrangular and distributed in a scattered pattern. the pore size is in nanometres to micrometres. the intragranular pores mainly include the following: (1) dissolution/mold pores formed by the partial/complete dissolution of particles (fig. 6a, b), the pore size can reach micron leve ls; (2) linear pores along the cleavage of mica and clay flakes or plates (fig. 6c); these pores are mostly less than 1 μm; (3) pores within fossils; and (4) internal pores of other particles, such as spherulite. the intergranular pores mainly appear between the mineral particles, including the intercrystalline pores, pores between clay mineral particles, and the marginal pores of rigid particles. a large number of the pores occur between clay mineral particles and are intercrystalline pores of the niutitang formation shale (fig. 6d, e), the intercrystalline pores of pyrite have a smaller pore size, mainly between 200 and 400 nm. most of the microfractures in the shale samples were developed in organic matter (fig. 6f). a small number of organic pores developed in the shale of the niutitang formation (fig. 6g). 4.3.3. reservoir porosity and permeability characteristics in unconventional oil and gas reservoirs, porosity and permeability are the main parameters of reservoir evaluation, as they directly affect the gas content and the exploration potential of the shale gas. in particular, the permeability is an important parameter for assessing the industrial value of the shale oil and gas development. the shale generally has the characteristics of poor permeability, strong compactness, and strong heterogeneity. the effective porosity of the shale in the study area is 3.5%–7.2%, (average 5.35%). the permeability is mainly distributed between 0.011 – 0.028 × 10–3μm2, (average 0.0195×10-3μm2). therefore, the niutitang formation shale is a low porosity and permeability reservoir. 4.3.4. diagenesis the common diagenesis in the shale mainly includes the compaction, cementation, dissolution, organic matter maturation, and transformation of clay minerals. however, these surface outcrop samples were subject to greater oxidation and eluviation than well samples would. recognition of mineral morphology under scanning electron microscope is low. combined with the qualitative analysis of the electron probe, it is believed that the diagenesis types of the niutitang formation in the study area mainly included compaction, dissolution and organic matter maturation. compaction is the main type of shale diagenesis, accompanied by the entire process of sedimentary diagenesis. shale has relatively weak resistance to compaction because of the presence of clay minerals. under compaction, the clay grain frame will gradually deform, the porosity will decrease, and the interlayer water will greatly reduce. compaction is one of the main reasons for densification of the niutitang formation shale in the xixiang– zhenba area (velde, 1996; kong et al., 2016). the identification indicators of compaction are mainly orientation arrangement of mineral particles to a certain extent in the niutitang formation shale samples (fig. 6h), but the orientation is not obvious due to the complicated geological movement experienced in the later periods. dissolution is related to acidic water or organic acids produced during the maturation process of the organic matter. when these acidic fluids are in contact with soluble components (feldspar or carbonate minerals), dissolution occurs, forming a large number of dissolution pores, which are beneficial for increasing the porosity of the shale. in addition, the maturation of organic matter produced a small number of organic pores, most figure 7. (a) comb-like folds in the south; (b) trough-like folds in the northeast (chen et al., 2008). g eo lo gi a c ro at ic a geologia croatica 73/156 of which are residual pores during hydrocarbon generation observed under a microscope (fig. 6g). 4.4. preservation conditions the preservation conditions directly affect the shale gas volume and composition of the shale gas reservoirs (wang et al., 2009). the buried depth of the niutitang formation shale is mainly 1500–4500m, and the underlying strata is dolomite of the sinian dengying formation of sinian age, with a poor preservation condition; the overlying strata is the muddy siltstones and the siltstone of the cambrian shipai formation with good reservoir seal qualities (fig. 3). the hannan–micang mountain uplift is to the west of the area, and the stratum itself is relatively stable. comblike folds are distributed in the south, with weak deformation (fig. 7a). trough-like folds are distributed in the northeast, with strong stratum deformation, and the degree of deformation weakens from east to west (fig. 7b). the middle part is the transition area between the trough-like folds and comb-like folds, and the deformation is not strong. at present, the shale gas reservoirs discovered in the sichuan basin and surrounding areas are mainly located in this transition area, such as the fuling shale gas reservoir (sun & luo, 2016; wei et al., 2019). therefore, the structural preservation conditions in the western, central, and southern regions of the study area are better. 4.5. shale gas-bearing capacity the china geological survey drilled the well x-1 in zhenba county, to a total depth of 1772 m. this resulted in the first discovery of the cambrian niutitang formation shale gas reservoir in the study area, and the shale of the niutitang formation was drilled accumulatively for 90m. the on-site analytical gas content <2.92 m3/t, the total gas content is <6.04 m3/t, and a high-quality shale (toc>2%) is mainly developed in the upper middle and lower middle parts of the niutitang formation (depths 1688–1717m, 1726.5–1477m). the well log curves have high–natural gamma, high-acoustic, low-density, and low-resistance characteristics (fig. 8). the zhenba area is listed as one of the most favourable areas in the sichuan basin and surrounding areas, with a natural gas commercial exploitation value (china geological survey, 2014). figure 8. column diagram of the well x-1 (china geological survey, 2014). g eologia c roatica xie et al.: geological conditions and gas-bearing evaluation of the niutitang formation shale in the xixiang–zhenba area, china 57 the shale gas is present in the shale in the adsorption state. at present, the isothermal adsorption simulation method is often used to determine the adsorption capacity of shale, so as to obtain the gas content of shale. the method needs to establish a relationship model between the adsorption gas content and pressure and temperature. using the following formula: va = vl × p/(p + pl) where va is the calculated adsorption gas content, m3/t; vl is the langmuir volume, m3/t; pl is the langmuir pressure, mpa; and p is the stratum pressure, mpa. according to the results of the isothermal adsorption experiment, the saturated adsorption capacity of the niutitang formation shale is 0.61-1.15m3/t, indicating that it has a high adsorption capacity. it was discovered that the higher the shale pressure, the higher the adsorption gas content, and the two are positively correlated. at the same time, the maximum adsorption gas content and toc content of the shale are also closely related. as shown in figure 9, the shales with the toc of 2.47%, 3.49%, 6.96% and 7.23% have the saturation adsorption capacity of 0.92m3/t, 0.61 m3/t, 1.01 m3/t and 1.15m3/t, respectively. generally, the higher the toc content of the sample, the higher the adsorption capaci ty. combined with previous research results (chen et al., 2018), the sample toc is considered to be proportional to the maximum adsorbed gas content. in summary, the shale in the niutitang formation of the study area has high gas content, and the gas-bearing potential of the shale could be roughly evaluated using the toc content result. 5. conclusions the following conclusions are drawn from this study: (1) in the niutitang formation in the study area, two sedimentary subfacies, namely the deep-water shelf subfacies and the shallow-water shelf subfacies are developed. black carbonaceous shale, silty shale, and black carbonaceous siliceous shale with siltstone and marl prevailed. (2) in the study area, the thickness of the shale increases from south to north, from east to west, high quality source rocks are mainly distributed in the fucheng and dahe areas. black carbonaceous shale is the organic rich source rock in higher maturity stage of thermal transformation (high-over mature stage of thermal evolution). the source rock mostly contains kerogen type i and ii, kerogen that is favourable for hydrocarbon generation. (3) the reservoir has a high content of brittle minerals and cracks. the clay mineral content is relatively low, mainly illite, followed by the mixed layer of illite and smectite, which is beneficial for the adsorption performance of the shale. the pore types mainly included intragranular pores, intergranular pores, and organic pores, providing good spaces for the storage of shale gas. the gas shale reservoir has low permeability and low porosity. the western, central, and southern regions of the study area have good preservation conditions. (4) the shale gas reservoir in the niutitang formation has good reservoir-forming conditions, and the shale has a high adsorption capacity. it also has a good gas-bearing property, indicating a certain resource potential. these findings are a good foundation for future research and development work in this area. acknowledgement the authors would like to acknowledge the “project on shale gas geological survey in xixiang-zhenba area, shaanxi province (project no. 20170104)”, and “research project on occurrence law of the tar-rich coal and its beneficial mineral resources in shaanxi province, china (project no. 20180304)”, which collectively funded this project. figure 9. isothermal adsorption experiments of the shale samples. g eo lo gi a c ro at ic a geologia croatica 73/158 references burnaman, m.d. & shelton, j. (2009): shale gas play screening and evaluation criteria.– china petroleum exploration, 14/3, 51–164. berman, a.e. (2009): shale plays and lower natural gas prices: a time for critical thinking.– world oil, 230/1, 15. curtis, j.b. (2002): fractured shale-gas systems.– aapg bulletin, 86/11, 1921–1938. doi: 10.1306/61eeddbe-173e-11d7-8645000102c1865d chen, x.l., zhai, g.y., bao, s.j., pang, f., wang, j.z. & tong, c.c. (2018): shale gas accumulation and gas-bearing properties of niutitang formation in well zhendi 1, zhenba region of southern shaanxi province.– china mining magazine, 27/b06, 101–106. cao, q.y. (1985): identification of microcomponents and types of kerogen under transmitted light – petroleum exploration and development, 6/5, 14–24. chen, g.c., zhang, j.l., wang, z.c., dong, h.b. & chen, j.y. (2008): regional geological survey map of nanjiang area (geological map 1:1250,000).– shaanxi mineral resources and geological survey. durham, l.s. (2005): barnett shale play still going strong.– aapg explorer, 4–6 p. dong, d.z., cheng, k.m., wang, y.m., li, x.j., wang, s.j. & huang, j.l. (2010): forming conditions and characteristics of shale gas in the lower palaeozoic of the upper yangtze region china.– oil & gas geology, 31/3, 288–299. doi: 10.11743/ogg20100304 gong, d.x., lin, j.h., tang, y.f., wu, c.h. & song, h.y. (2010): organic geochemical characteristics of palaeozoic marine source rocks in northern margin of the upper yangtze platform.– lithologic reservoirs, 22/3, 31–37. doi: 10.3969/j. issn.1673-8926.2010.03.007 guo, x.s., hu, d.f., wen, z.d., jiang, s.l. & wang, z.y. (2014): major factors controlling the accumulation and high productivity in marine shale gas in the lower palaeozoic of sichuan basin and its periphery: a case study of the wufenglongmaxi formation of jiaoshiba area.– geology in china, 41/3, 893–901. doi: 10.3969/j.issn.1000-3657.2014.03.016 hu, m.y., deng, q.j. & hu, z.g. (2014): shale gas accumulation conditions of the lower cambrian niutitang formation in the upper yangtze region.– oil & gas geology, 35/2, 272–279. doi: 10.11743/ogg20140215 huang, l. & shen, w. (2015): characteristics of the pores and controlling factors of a shale gas reservoir: a case study from longmaxi formation of the upper yangtze region, china.– earth science frontiers, 22/1, 374–385. doi: 10.13745/j. esf.2015.01.032 hill, d.g. & nelson, c.r. (2000): reservoir properties of the upper cretaceous lewis shale – a new natural gas play in the san juan basin.– aapg bulletin, 84/8, 1240. ju, y.w., bu, h.l. & wang, g.c. (2014): main characteristics of shale gas reservoir and its effect on the reservoir reconstruction.– advances in earth science, 29/4, 492–506. doi: 10.11867/j.issn.1001-8166.2014.04.0492 jarvie, d.m., hill, r.j., ruble, t.e. & pollastro, r.m. (2007): unconventional shale-gas systems: the mississippian barnett shale of north-central texas as one model for thermogenic shale-gas assessment.– aapg bulletin, 91/4, 475–499. doi: 10.1306/12190606068 jin, z.j., hu, z.q., gao, b. & zhao, j.h. (2016): controlling factors on the enrichment and high productivity of shale gas in the wufeng and longmaxi formations, southeastern sichuan basin.– earth science frontiers, 23/1, 001–010. doi:10.13745/ j.esf.2016.01.001 kong, l.m., wan, m.x., yan, y. x., zou, c.y., liu, w.p., tian, c., yi, l. & zhang, j. (2015): reservoir diagenesis research of silurian niutitang formation in sichuan basin.– natural gas geoscience, 26/8, 1547–1555. li, r. x., zhu, r.j., liu, h.q., zhang, y.n. & zhu, d.m. (2013): characteristics of palaeozoic source rocks in dabashan foreland tectonic belt.– annual meeting of the chinese society of minerals, petrology and geochemistry, 92–93. li, t. (2010): the study of neoproterozoic tectonic-magmatic events in the northern margin of the yangtze continent.– thesis, master. chang’an university, 1–69 p. (in chinese with english abstract). li, y.x., nie, h.k. & long, p.y. (2009): development characteristics of shale rich organic shale and strategic selection of shale gas in china.– natural gas industry, 29/12, 115–118. doi: 10.3787/j.issn.1000-0976.2009.12.034 lu, x.c., li, f.h. & watson, a.t. (1995): adsorption measurements in devonian shales.– fuel, 74/4, 599–603. liu, z.j. (2012): gas evaluation of lower palaeozoic shale in southeastern chongqing.– thesis, master. china university of geosciences, 1–104 p. (in chinese with english abstract). loucks, r.g. & ruppel, stephen, c. (2007): mississippian barnett shale: lithofacies and depositional setting of a deep-water shale-gas succession in the fort worth basin, texas.– aapg bulletin, 91/4, 579–601. doi: 10.1306/11020606059 mao, q., zou, g.f., zhang, h.m., jin, h. & huang, h.b. (2006): discussion on geodynamic evolution and oil / gas prospect of the sichuan basin.– natural gas industry, 26/11, 7–10. doi: 10.3321/j.issn:1000-0976.2006.11.0030 mu, c.l., zhou, k.k., liang, w. & ge, x.y. (2011): early palaeozoic sedimentary environment of hydrocarbon source rocks in the middle upper yangtze region and petroleum and gas exploration.– acta geologica sinica, 85/4, 526–532. pu, b.l., jiang, y.l., wang, y., bao, s.j. & liu, x.j. (2010): reservoir-forming conditions and favorable exploration zones of shale gas in lower silurian longmaxi formation of sichuan basin.– acta petrolei sinica, 31/2, 225–230. rach, n.m. (2004): drilling expands in texas’ largest gas field.– oil & gas journal, 102/3, 45–50. doi: 10.1016/j.ydbio.2010.05.240 reed, r.m, loucks, r. g. & jarvie, d.m. (2007): nanopores in the mississippian barnett shale: distribution morphology, and possible genesis.– gas shales of north america, 39/6, 358. shen, j.a., li, x.p., an, s.t., jin, h. & hu, p.q. (2017): reservoir space and mineral composition of the shale from silurian longmaxi formation in sichuan basin.– geology and resources, 26/6, 590–595. doi: 10.3969/j.issn.1671–1947. 2017.06.010 schettler, p.d. & parmoly, c.r. (1990): the measurement of gas desorption isotherms for devonian shale.– gri devonian gas shale technology review, 7/1, 4–9. shao, x.h., pang, x.q., hu, t., xu, t.w., xu, y.a., tang, l., li, h. & li, l.l. (2019): microscopic characteristics of pores in es3 shales and its significance for hydrocarbon retention in dongpu sag, bohai bay basin.– oil & gas geology, 40/01, 67–77. doi: 10.11743/ogg20190107 sun, j. & l, b. (2016): structural deformation and its influences on gas storage in fuling shale gas play, the sichuan basin.– oil & gas geology, 37/06, 809–818. doi: 10.11743/ogg20160602 ulmishe, g.f. & klemmme, h.d. (1990): depositional controls, distribution, and effectiveness of world’s petroleum source rocks.– us geological survey bulletin, 1931, 59. velić, j., malvić, t., cvetković, m. & vrbanac, b. (2012): reservoir geology, hydrocarbon reserves and production in the croatian part of the pannonian basin system.– geologia croatica, 65/1, 91–101. doi: https://doi.org/10.4154/ gc.2012.07 velde, b. (1996): compaction trends of clay-rich deep sea sediments.– marine geology, 133/3–4, 193–201. doi: 10.1016/0025-3227(96)00020-5 wang, b. (2010): genetic characteristics of organic fluids in the dabashan foreland structure.– thesis, master. chang’an university, 1–83 p. (in chinese with english abstract). wang, h., jiang, c.f., zhang, l. & gao, c. (2017): mineralogical characteristics of the shale from shanxi formation in southeastern ordos basin.– petrochemical industry technology, 24/6, 129–130. wang, j.j. (2016): a comparative study on shale gas geological character of longmaxi and niutitang formations in south china.– thesis, master. china university of geosciences (beijing), 1–68 p. (in chinese with english abstract). wu, c.j., zhang, m.f., ma, w.y., liu, y., xiong, d.m., sun, l. & tuo, j.c. (2014): organic matter characteristic and sedimentary environment of the lower cambrian niutitang shale in southeastern chongqing.– natural gas geoscience, 25/8, 1267–1274. doi: 10.11764/j.issn.1672-1926.2014.08.1267 wu, x.b., chen, j.x., hao, y.j. & na, z.q. (2013) discovery and geological significance of the silurian xintan formation seismite along the north margin of the yangtze plate.– northwestern geology, 46/2, 81–86. doi: 10.3969/j. issn.1009-6248.2013.02.010 wang, l.b., jiu, k., zeng, w.c., fu, j.l. & zhao, s. (2012): characteristics of lower cambrian marine black shale and evaluation of shale gas prospective area in qianbei area, upper yangtze region.– acta petrologica sinica, 29/9, 3263–3278. warlick, d. (2006): gas shale and cbm development in north america.– oil and gas financial journal, 3/11, 1–5. wang, s.j., wang, l.s., huang, j.l., li, x.j. & li, d.h. (2009): accumulation conditions of shale gas reservoirs in silurian of the upper yangtze region.– natural gas industry, 29/5, 45–50. wang, s.f., dong, d.z., wang, y.m., li, x.j., jin, l. & guan, q.z. (2015): a comparative study of the geological characteristics of marine shale gas between china and the united states.– natural gas geoscience, 26/9, 1666–1678. doi: 10.11764/j.issn.1672-1926.2015.09.1666 wei, g.q., yang, w., liu, m.c., xie, w.r., jin, h., wu, s.j., su, n., shen, j.h. & hao, c.g. (2019): distribution rules, main controlling factors and exploration directions of giant gas fields in the sichuan basin.– natural gas industry, 39/6, 1–12. yu, b.s. (2013): classification and characterization of the pores in shale gas reservoirs.– earth science frontiers, 20/4, 211–220. zhou, z.b., wang, d.q., wang, x.c., zhang, l.h. & zhao, z.f. (1999): analysis and development of potential natural gas market in sichuan basin.– natural gas industry, (03), 117–118. zhang, j.c., nie, h.k., xu, b., jiang, s.l., zhang, p.x. & wang, z.y. (2008): geological condition of shale gas accumulation in sichuan basin.– natural gas industry, 28/2, 151–156. doi: 10.3787/j.issn.1000-0976.2008.02.045 obituary professor boško lugović, phd  doi: 10.4154/gc.2013.20 geologia croatica 66/3 245–249 zagreb 2013 behind their scientific achievements, but professor lugović left his mark in every respect. we have lost a dear colleague with whom we shared the good and the bad, we have lost a good friend and a wise counselor, our students have lost a strict and demanding teacher, but also a person who understood and loved them. professor boško lugović, phd was born on november 15th, 1949 in šibenik. in his hometown, he attended elementary and high school before moving to zagreb, where he studied geology at the university of zagreb, faculty of science. he graduated in 1973, majoring in mineralogy and petrology. from april 1975, he was employed at the faculty of mining, geology and petroleum engineering, at the university of zagreb, where he continued to work until his untimely death. during his scientific and teaching career, professor boško lugović was dedicated to the field of igneous and metamorphic rocks. his postgraduate thesis was entitled „effusive rocks from the northwestern part of papuk mt.“. he defended his phd thesis entitled „gabbro peridotite rock association on the northwestern rim of the ophiolite maljen massif (with basic comparisons to some similar occurrences from the ophiolite belt in the dinarides)“ on december 15th, 1986. boško lugović was elected an assistant professor on january 11th, 1988, an associate professor on march 7th, 1997, and a full professor on december 13th, 2011. he taught courses at the department of mineralogy, petrology and mineral resources at faculty of mining, geo­ logy and petroleum engineering, dealing with the petrology of igneous and metamorphic rocks and methods of their research. over the last ten years, professor boško lugović was dedicated to a new discipline that combines geology and archeology where he had made a significant scientific contribution. following his research in this new scientific discipline, he designed and proposed the syllabus of the new course entitled „tephrochronology in the quaternary.“ during his scientific career at the university, professor boško lugović, phd paid a lot of attention to training and specialization in order to keep pace with current trends in geologia croaticageologia croatica our dear colleague and distinguished professor boško lugović, phd left us on may 12th this year. the cruel news saddened us deeply because this humble man has left an indelible mark on our community: at our faculty as a scientist, among students as an excellent teacher, in our hearts as a dear friend and colleague. eminent scientists usually leave geologia croatica 66/3geologia croatica 246 the world of science. he also trained and specialized during the development of his master’s thesis and during research for his doctoral dissertation. he was a visiting scientist, mainly in german and partly in austrian institutions: technische universität braunschweig, bvfa­geotechnisches ­ institut in vienna, montanuniversität in leoben, institute of petrology and geochemistry, university of karlsruhe. it should be emphasized that he had a longstanding scientific collaboration with professor rainer altherr, phd, and hans­ peter meyer, phd from mineralogical institute (now incorporated to institute of earth science) of the university of heidelberg and with professor albrecht hofmann, phd from the department of geochemistry at the max­planck institute in mainz, where professor lugović spent one year undertaking a postdoctoral specialization. during advanced training in these institutions, professor boško lugović, phd mastered instrumental analytical methods and applied them when interpreting the results of petrological and geochemical research related to genesis of igneous and metamorphic rocks of the dinarides and pannonian basin. at least once a year, he went to the mineralogical institute in heidelberg, where he had the opportunity to do up­to­date mineralogical analysis. applying modern techniques and methods in his investigations, his overall scientific work was based on reliable data. professor boško lugović’s contemporary approach to science was also acknowledged in the education of younger colleagues and researchers. he was actively involved as a mentor for several doctoral theses, fifteen graduate works, and three student’s works for the rector’s award. he wrote internal textbooks for the courses „petrology of igneous and metamorphic rocks“, „analyses of mineral assemblages“ and „instrumental methods of analysis“. professor lugović has been an active researcher in the national research projects and a member of international projects for igcp/unesco. he was also a leader of national research projects „cenozoic volcanism on the adriatic coast and the hinterland”, „igneous and pyroclastic rocks and their alteration” and „tecto­ nomagmatic correlation of fragmented oceanic lithosphere in the dinarides”. he was a collaborator in the national scientific project of croatian geological survey „magmatic, mantle and pyroclastic mesozoic rocks of northwestern croatia”. boško lugović was especially proud of his participation in scientific projects of the academy of sciences and arts of bosnia and herzegovina. he collaborated fruitfully with young petrologists from the university of tuzla where he mentored two phd theses (zehra salkić, phd and elvir babajić, phd). as an author or co­author, boško lugović published a total of 68 scientific papers, in eminent scientific journals, books, and in abstracts from national and international scientific meetings. some of the works are pioneering (multidisciplinary) including geoarchaeology. boško lugović was a member of the croatian geolo­ gical society, and vice president of the society from 1991 until 1993. he was a member of the editorial board of the journal „geologia croatica“ from 1991 until 1995. the scientific contribution of boško lugović is in the field of igneous, metamorphic and pyroclastic rocks in the dinarides, and their effect on the mineralization and its application in geoarchaeological studies. professor lugović leaves behind not only outstanding scientific contributions in the field of geology, but also the scientific enthusiasm in seeking answers to the mysteries of the earth. however, that was not his only area of interest. he considered himself primarily a teacher and his life were dedicated to the transfer of his extensive knowledge to the younger generations. he loved working with young people, giving lectures, exercises and field work. he encouraged young people in their efforts to cope with the difficulties of studying. he was able to choose the best way to approach each individual. his relationship with students was relaxed and unconventional. he will particularly be remembered by many generations for his cheerful approach to fieldwork when magmatic and metamorphic petrology was taught in a completely different, relaxed and very inspiring atmosphere, thanks to the serenity and distinctive style of professor lugović. all achievements of professor boško lugović, phd in science and teaching would not have been possible without the professor’s solid anchor – his family who were the foundation on which everything rested and of whom he was proud. we bid farewell to our dear colleague, exceptional teacher and a good friend and laid him to eternal rest at the graveyard in bilice. the cemetery overlooks the dalmatian karst, small fields planted with olive trees and vines ­ everything that professor lugović loved so much. in our memories his laughter still echoes, we can still remember his sayings and jokes. sometimes it seems like he only left us for a short time and he will be back soon (…it is impossible that a man so full of life passed away!). we say goodbye to our dear friend with the help of yesenin’s verses: goodbye, my friend, goodbye my friend, you are in my heart. it was preordained we should part and be reunited by and by. dunja aljinović and vesnica garašić bibliography scientific papers (current contents, science citation index, sci expanded) slovenec, d. & lugović, b. (2012): evidence of the spreading culmination in the eastern tethyan repno oceanic domain assessed by the petrology and geochemistry of n­morb extrusive rocks from the mt. medvednica ophiolite mélange (nw croatia).– geologia croatica, 65, 435–446. doi: 10.4154/gc.2012.32 šegvić, b., šešelj, l., slovenec, da., lugović, b. & ferreiro mählmann, r. (2012): composition, technology of manufacture, and circulation of hellenistic pottery from the eastern aljinović and garašić: obituary professor boško lugović, phd geologia croatica 247 adriatic: a case study of three archaeological sites along the dalmatian coast, croatia.– geoarchaeology, 27, 63–87. doi: 10.1002/ gea.21379 slovenec, da., lugović, b., meyer, h.­p. & garapić šiftar, g. (2011): tectono­magmatic correlation of basaltic rocks from ophiolites melánges at the north­east surface tips of sava­var­ dar suture zone (mts. kalnik and ivanščica, north croatia) constrained by geochemistry and petrology.– ofioliti, 36, 77–100. doi: 10.4454/ofioliti.v36.i1.5 slovenec, da., lugović, b. & vlahović, i. (2010): geoche­ mistry, petrology and tectonomagmatic significance of basaltic rocks from the ophiolite mélange at the nw external­internal dinarides junction (croatia).– geologica carpathica, 61, 273–292. doi: 10.2478/v10096­010­0016­1 slovenec, da. & lugović, b. (2009): geochemistry and tectono­ magmatic affinity of mafic extrusive and dyke rocks from the ophiolite mélange of the sw zagorje­mid­transdanubian zone (mt. medvednica, croatia).– ofioliti, 34, 63–80. doi: 10.4454/ofioliti. v34i1.378 ustaszewski, k., schmid, s.m., lugović, b., schuster, r., schaltegger, u., bernoulli, d., hottinger, l., kounov, a., fügenschuh, b. & schefer, s. (2009): late cretaceous intra­oceanic magmatism in the internal dinarides (northern bosnia and herzegovina): implications for the collision of the adriatic and european plates.– lithos, 108, 106–125. doi: 10.1016/j. lithos.2008.09.010 šegvić, b., lugović, b., bermanec, v., tadej, n. & panjkota, l. (2008): si­p impure al­goethite mineralization on dugi otok (central adriatic, croatia).– geologia croatica, 61, 19–26. doi: 10.4154/gc.2008.04 slovenec, da. & lugović, b. (2008): amphibole gabbroic rocks from the mt. medvednica ophiolite mélange (nw croatia): geochemistry and tectonic setting.– geologica carpathica, 59, 277–293. lugović, b., slovenec, d. & halamić, j. & altherr, r. (2007): petrology, geochemistry and tectonic significance of mesozoic ultramafic rocks from the zagorje­mid­transdanubian zone in croatia.– geologica carpathica, 58, 511–530. lugović, b., šegvić, b. & altherr, r. (2006): petrology and tectonic significance of greenschists from the medvednica mts. (sava unit, nw croatia).– ofioliti, 31, 39–50. doi: 10.4454/ofioliti. v31i1.326 altherr, r., lugović, b., meyer, h­p. & majer, v. (1995): early miocene post­collisional calc­alkaline magmatism along the easternmost segment of the periadriatic fault system (slovenia and croatia).– mineral. petrol., 54, 225–247. lugović, b., altherr, r., raczek, i., hofmann, a.w. & majer, v. (1991): geochemistry of peridotites and mafic igneous rocks from the central dinaric ophiolite belt, yugoslavia.– contrib. mi­ neral. petrol., 106, 201–216. peer-reviewed papers slovenec, da., lugović, b. & slovenec, d. (2012): sekundarne mineralne parageneze u mafitnim ekstruzivnim stijenama iz ofiolitnog melanža medvednice (hrvatska) [secondary mineral paragenesis in the mafic extrusive rocks from the mt. medvednica ophiolite mélange (croatia)].– rudarsko­geološko­naftni zbornik, 25, 33–46. lugović, b., šegvić, b. & šegvić, t. (2008): mn­crust todorokite mineralization on sw backshore cretaceous limestones from the island of dugi otok (central adriatic, croatia).– acta adriatica, 49, 53–63. dudjak, d., lugović, b. & šegvić, b. (2007): andezitne vulkanske bombe u miocenskim pješčenjacima ravne gore u sjeverozapadnoj hrvatskoj [andesitic volcanic bombs in ravna gora miocene sandstones in the northwest croatia].– zbornik radova rgg fakulteta, 34, 197–208. maričić, m., šegvić, b. & lugović, b. (2007): rekonstrukcija drevnih plovnih putova petrološko­geokemijskom analizom vulkanskih artefakata s dugog otoka (središnji jadran, hrvatska) [reconstruction of ancient waterways by petrological-geochemical analysis of volcanic artifacts from the island of dugi otok (central adriatic, croatia)].– zbornik radova rgg fakulteta, 34, 209–220. radić, d., lugović, b. & marjanac, lj. (2007): neapolitan yellow tuff from the pleistocene deposits in the vela spila cave (island of korčula, croatia): an excellent marker of the pelaeolitic­mesolitic transition.– opvscvla archaeologica, 31, 7–26. babajić, e., salkić, z., lugović, b. & salihović, s. (2006): geohemijska geotektonska diskriminacija tercijarnih vulkanskih sti­ jena okoline maglaja [geochemical geotectonic discrimination of tertiary volcanic rocks surrounding mt. maglaj].– zbornik radova rgg fakulteta, 30, 39–50. sekelj ivančan, t., tkalčec, t. slovenec, dr. & lugović, b. (2005): analyse der keramik aus der frühmittelalterlichen siedlung am standort ledine bei torčec.– pril. inst. za arheol. zagrebu, 22, 141–186. radić, d. & lugović, b. (2004): petrographic and geochemical co­ rrelation between artifacts from the mesolithic layers of vela spila and magmatic rocks of central dalmatian islands.– opvscvla archaeologica, 28, 7–18. lugović, b., altherr, r., marjanac, t., & meyer, h­p. (1998): orogenic signatures in late cenozoic volcanic rocks from the northern external dinarides, croatia.–acta vulcanologica, 10, 55–65. lugović, b. & podrug, e. (2008): dacitni ignimbrit – lički primjer vulkanskog kamena za izradbu glačanih alatki [dacitic ignimbrites – lika example volcanic stone to create polished tools].– izdanja hrvatskog arheološkog društva, 23, 29–39. majer, v., lugović, b. & vragović, m. (1993): kloritoidni škriljci dinarida i susjednih oblasti [chloritoid schists in the dina­ rides and the neighbouring regions].– rad hazu, 26 (463), 159– 193. majer, v. & lugović, b. (1991): metamorfne stijene s alkalnim amfibolima („glaukofanski škriljci“) u jugoslaviji [metamorphic rocks with alkalic amphiboles („glaucophane schists”) in yugoslavia – in croatian with english abstract].– rad hazu, 25 (458), 103–129. majer, v., lugović, b. & trubelja, f. (1991): metamorfizam bosanskih škriljavih planina ­ prethodna istraživanja [metamorphism of bosnian schist mountains ­ previous research].– radovi anu bih, 13 (87), 141–158. trubelja, f. & lugović, b. (1991): mineralogija boksita u bazenu posušje (zapadna hercegovina) [mineralogy of bauxite in the posušje basin (western herzegovina)].– radovi anu bih, 13 (87), 129–140. lugović, b., majer, v. & stumpfl, e.w. (1990): geochemical characteristics of basaltic andesites from baranja (croatia, yugoslavia).– geol. vjesnik, 43, 135–142. majer, v. & lugović, b. (1985): metamorfne stijene u ofiolitnoj zoni banije, jugoslavija. ii. amfiboliti (metabaziti) [metamorphic rocks in banija ophiolitic zone, yugoslavia. ii. amphibolites (metabasic rocks)].– acta geol. jazu, 15, 25–49. lugović, b. & majer, v. (1983): eruptivi senjske drage (vratnika) kod senja (hrvatska, jugoslavija) [magmatic rocks of senjska draga (vratnik) near senj (croatia, yugoslavia)].– geol. vjesnik, 36, 157–181. lugović, b. (1983): efuzivne stijene sjeverozapadnog dijela papuka [extrusive rocks of northwest part of mt. papuk].– geol. vjesnik, 36, 131–156. geologia croatica 66/3geologia croatica 248 book chapters durn, g., aljinović, d., crnjaković, m. & lugović, b. (2007): heavy and light mineral fractions indicate polygenesis of extensive terra rossa soils in istria, croatia.– in: mange, m. & wright, d.t. (eds.): heavy minerals in use. developments in sedi­ mentology, 28, 767–805. radić, d., lugović, b. & marijanac, lj. (2006): vulkanski pepeo u pleistocenskim slojevima vele spile. luško libro [volcanic ash in the pleistocene layers of vele spile. luško libro].– godišnjak društva vela luka, 14, 51–61. lugović, b. & slovenec, da. (2004): mantle harzburgites (serpentinites) from gornje orešje (medvednica mts., croatia).– excursion guide, joint meeting of croatian and hungarian geological societies on geology of the zagorje­mid­transdanubian zone, 22.– 24.10.2004, 40–45, zagreb. conference presentations, invited lectures, proceedings, abstract-books garašić, v., lugović, b., sekušak, m., meyer, h.­p., vrkljan, m. & schuster, r. (2013): first occurrence of dumortierite in croatia: a potential evidence of tetrahedral ti substitution for si. goldschmidt 2013 conference abstracts.– mineralogical magazine, 77/5, 1141. garapić, g., faul, u. & lugović, b. (2012): western dinaride mantle peridotites: krivaja­konjuh case study. agu fall meeting san francisco 3–7 december. t41c­2599. babajić, e., lugović, b., salkić, z., babajić, a. (2011): he­ mi jski sastav olivina mafitnih stijena krivaja­konjuh ofiolitnog kompleksa u funkciji petroloških razmatranja [the chemical composition of olivine in mafic rocks of krivaja­konjuh ophiolite complex in the sense of petrological considerations].– zbornik sažetaka, iv savjetovanje geologa bosne i hercegovine sa međunarodnim učešćem, sarajevo, 28. i 29. 10. 2011., 56–57. salkić, z., lugović, b., salihović, s. & babajić, e. & ba­ bajić, a. (2011): mineraloško­petrografska i geohemijska obilježja tercijarnih dacita kolića, kod nemile [mineralogical-petrographic and geochemical characteristics of tertiary dacite of kolić, at nemila].– zbornik sažetaka, iv savjetovanje geologa bosne i hercegovine sa međunarodnim učešćem, sarajevo, 28. i 29. 10. 2011., 47–48. simat, s. & lugović, b. (2011): petrografsko – geokemijska obilježja i arheološki značaj vulkanskih žrvnjeva iz bribirske glavice u dalmaciji [petrographic-geochemical characteristics and archaeological significance of volcanic grindstones from bribirske glavice in dalmatia].– zbornik sažetaka, iv savjetovanje geologa bosne i hercegovine sa međunarodnim učešćem, sarajevo, 28. i 29. 10. 2011., 50–51. slovenec, da. & lugović, b. (2010): alteracijski procesi u mafitnim ekstruzivnim stijenama iz ofiolitnog melanža medvednice (hrvatska) [alteration processes in mafic extrusive rocks from ophiolite melange medvednica (croatia)].– in: horvat, m. (ed.): abstracts book, 4. croatian geological congress, šibenik, 151–152. lipovac vrkljan, g. & lugović, b. (2008): local ceramic production from the workshop of sextus metilius maximus in crikvenica – amphorae of the „crikvenica” variant.– international archaeological colloquium, roman ceramic and glass manufactures, production and trade in the adriatic region, crikvenica october 23–24, 2008, 34–36. salkić, z., lugović, b. & babajić, e. (2008): hemijska klasifikacija i nomenklatura tercijarnih vulkanskih stijena sjeveroistočne bosne [chemical classification and nomenclature of tertiary volcanic rocks of the northeast bosnia].– in: filipović, a. (ed.): zbornik radova, iii savjetovanje geologa bih s međunarodnim učešćem, neum, 30. –31.10.2008., udruženje/udruga geologa bosne i hercegovine, 503–511. biševac, v., šegvić, b., tibljaš, d. & lugović, b. (2007): mineralogy of altered tephra layers in the upper jurassic lemeš deposits near maovice (dalmatia, croatia).– in: rocha, f., terroso, d. & quintela, a. (eds.): euroclay 2007 abstract book, universidade de aveiro, portugal, 75–76. lugović, b. & podrug, e. (2007): arheološko značenje artefakata od dacitnog ignimbrita na prapovijesnim lokalitetima u sjeverozapadnoj dalmaciji i lici [the archaeological significance of the artifacts made from dacitic ignimbrites at prehistoric sites in northwestern dalmatia and lika].– obavijesti hrvatskog arheološkog društva, 39/2, p. 19. ustaszewski, k., schmid, s.m., lugović, b., schuster, r., schaltegger, u., fügenschuh, b., kounov, a., bernoulli, d., hottinger, l. & schefer, s. (2007): the late cretaceous supra­subduction magmatism of north kozara (northern bosnia and herzegovina): implications for the cretaceous to paleogene collisional history between tisza and the dinarides.– egu2007. geophysical research abstracts, 9, 03659. garašić, v., krkač, m., lugović, b., tadej, n., vrkljan, m., garapić šiftar, g. & majer, v. (2006): petrolgical characteristics of ladinian magmatic rocks from the external dinarides (vratnik, croatia). 84. jahtrestagung der deutschen mineralogischen gesellschaft, hannover, 2006.– beih. z. eur. j. mineral., vol. 18, p. 44. lugović, b. (2006): petrological and geochemical signatures of dinaric ophiolites. lecture held on 8 february 2006 in institute for geology and palaeontology in basel, switzerland. lugović, b., šegvić, b., babajić, e. & trubelja, f. (2006): evidence of short­living intraoceanic subduction in the central dinarides, konjuh ophiolite complex (bosnia­herzegovina).– proceedings, mesozoic ophiolite belts of northern part of the balkan peninsula, international symposium, belgrade­banja luka, may 31 – june 6, 72–75. lugović, b., miletić, d. & tari kovačić, v. (2006): lithospheric extension in the east adria: evidence from ultraalkali volcanic rocks in the pliocene sedimentary succession of dugi otok depression.– adria 2006, international geological congress on the adriatic area, urbino 19–20 june, abstracts, 71–73. lugović, b. & šegvić, b. (2006): geological and archaeological significance of volcanic artefacts from the east adriatic sea.– adria 2006, international geological congress on the adriatic area, urbino 19–20 june, abstracts, 69–71. lugović, b., crnjaković, m. & biševac, v. (2006): mineralogical signatures of weathered late holocene ash layer from the island mljet in croatia.– abstract book, 3rd mid­european clay conference­mecc 06, opatija 18–23. september 2006, p. 78. lugović, b. & kralj, p. (2006): spinel lherzolite xenoliths from upper pliocene potassic trachybasalts at grad, ne slovenia.– book of abstracts, 2. slovenski geološki kongres, idrija 26.–28. september 2006, p. 64. salkić, z., lugović, b., trubelja, f. & salihović, s. (2006): geohemijska i geotektonska obilježja tercijarnih vulkanskih stijena okoline srebrenice, sjeveroistočna bosna [geochemical and geotectonic characteristics of tertiary volcanic rocks surrounding srebrenica, north-eastern bosnia].– in: vujnović, l. (ed.): zbornik sažetaka, ii. savjetovanje geologa bosne i hercegovine s međunarodnim učešćem, teslić, 23­24. novembar 2006., udruženje geologa bosne i hercegovine, 91–92. šegvić, b., toševski, a., števanić, d., biševac, v. & lugović, b. (2006): altered tephra layers in the upper jurassic lemeš deposits near maovice (dalmatia, croatia): clay mineralogy and basic soil mechanic properties.– abstract book, 3rd mid­european clay conference­mecc 06, opatija 18–23. september 2006, p. 104. aljinović and garašić: obituary professor boško lugović, phd geologia croatica 249 ustaszewski, k., schmidt, s.m., lugović, b., schuster, r., caron, m., rettenmund, c., & kounov, a. (2006): does the sava-zone represent a remnant of the vardar ocean and when did it close? – strucutre, geochemistry and age of the kozara ophiolites (northern bosnia-herzegovina).– proceedings, mesozoic ophiolite belts of northern part of the balkan peninsula, international symposium, belgrade-banja luka, may 31–june 6, 136–138. lugović, b., tari, v. & miletić, d. (2005): voluminous lower pleistocene volcaniclastic deposits from the northern adriatic offshore (croatia): where were the edifices?– in: velić, i., vlahović, i. & biondić, r. (eds.): abstract book, 3rd croat. geol. congress, opatija, 87–88. slovenec, da. & lugović, b. (2005): pumpellyiti u mafitnim ekstruzivnim stijenama iz ofiolitnog melanža medvednice (hrvatska) [pumpellyite in the extrusive mafic rocks from the ophiolite melange of the medvednica mt. – in croatian].– in: velić, i., vlahović, i. & biondić, r. (eds.): abstract book, 3rd croat. geol. congress, opatija, 129–130. slovenec, dr. & lugović, b., sekelj ivančan, t. & tkalčec, t. (2005): mineraloško-petrografske značajke ranosrednjovjekovnih keramika iz arheološkog lokaliteta torčec-ledine kraj koprivnice [mineralogical-petrographical characteristics of early medieval ceramics from the archaeological site torčec-ledine near koprivnica].– in: velić, i., vlahović, i. & biondić, r. (eds.): abstract book, 3rd croat. geol. congress, opatija, 277–278. šegvić, b., lugović, b. & ignjatić, s. (2005): petrochemical and geotectonic characteristic of the amphibolites from sw zagorjemid-transdanubian shear zone (kalnik mt., croatia).– in: velić, i., vlahović, i. & biondić, r. (eds.): abstract book, 3rd croat. geol. congress, opatija, 143–144. marjanac, lj., miculinić, k., bergant, s., lugović, b. & radić, d. (2004): sedimentology and stratigraphy of vela cave preliminary results (island korčula, croatia).– 12th international karstological school, „classical karst“, dating of cave sediments, 21–24.06.2004, postojna. marjanac, lj., miculinić, k., bergant, s., lugović, b. & radić, d. (2004): sedimentology and stratigraphy of vela cave preliminary results (island korčula, croatia).– in: kniewald, z. (ed.): zbornik sažetaka postera znanstvenih novaka izlaganih u inozemstvu 2002., 2003., i 2004. god., i. dio (prir., teh. i bioteh. znan.), akademija tehničkih znanosti hrvatske, zagreb, p. 108. salkić, z., lugović, b., trubelja, f. & salihović, s. (2004): geohemijske i geotektonske karakteristike tercijarnih vulkanskih stijena centralne bosne [geochemical and geotectonic characteristics of tertiary volcanic rocks of central bosnia].– in: hrvatović, h. (ed.): zbornik sažetaka, i. savjetovanje geologa bosne i hercegovine s međunarodnim sudjelovanjem, kladanj, 24–25.06.2004. udruženje geologa bosne i hercegovine, 108–109. salkić, z., lugović, b., trubelja, f. & salihović, s. (2004): petrografske, geohemijske i geotektonske karakteristike tercijarnih vulkanskih stijena centralne bosne [petrographic, geochemical and geotectonic characteristics of tertiary volcanic rocks of central bosnia].– in: hrvatović, h. (ed.): zbornik radova, i. savjetovanje. geologa bosne i hercegovine s međunarodnim sudjelovanjem kladanj, 24–25. 6. 2004., 185–197. slovenec, da. & lugović, b. (2003): ca-amphiboles in the gabbroic rock blocks from the ophiolite mélange of the medvednica mts. (croatia).– 22nd ias meeting of sedimentology, opatija 2003, abstracts book, p. 200. olker, b., altherr, r. & lugović, b. (2001): metamorphic evolution of mafic granulites from the metamorphic sole of central dinaric ophiolites (bosnia-herzegovina).– eug xi meeting, 8–12 april 2001, strasbourg, france, abstracts, 320–321. lugović, b. (2000): postlutetni vulkanski epiklasti na sjevernojadranskim otocima (hrvatska)[post lutetian volcanic epiclasts from the northern adriatic islands (croatia) – in croatian].– in: vlahović, i. & biondić, r. (2000): proceedings of 2. croatian geological congress, 17-20.05.2000. cavtat-dubrovnik, 317–320. miletić, d. & lugović, b. (2000): kontrastni ultraalkalijski litoklasti iz pliocenskih naslaga u podmorju dugootočkog bazena (hrvatska) [contrasting ultraalkali lithoclasts in pliocene sedimentary rocks from the depression of dugi otok island, adriatic off-shore (croatia) – in croatian].– in: vlahović, i. & biondić, r. (2000): proceedings of 2. croatian geological congress, 17-20.05.2000. cavtat-dubrovnik, 327–331. slovenec, da. & lugović, b. (2000): ultramafitne kumulatne stijene ofiolitnog kompleksa medvednice (sjeverozapadna hrvatska) [ultramafic cumulate rocks from the medvednica mts. ophiolite complex (northwestern croatia) – in croatian].– in: vlahović, i. & biondić, r. (2000): proceedings of 2. croatian geological congress, 17-20.05.2000. cavtat-dubrovnik, 379–385. miletić, d. & lugović, b. (1996): pliocene volcaniclastic sediments in the croatian adriatic off-shore region (drill-hole kruna-1).– international workshop: the role of impact processes in the geological and biological evolution of the planet earth, postojna, abstracts, 52–53, ljubljana. lugović, b. (1987): mafic-ultramafic cumulate rock series from the mt. maljen ophiolite complex (yugoslavia): petrology and geochemistry. symp. troodos 87: ophiolites and oceanic lithosphere.– geol. survey department, abstract of papers, nicosia, p. 64. lugović, b. (1987): an introduction to yugoslav ophiolites.– lecture held on 27 october, 1987 in max-planck-institute for chemistry in mainz, germany. available online november 06, 2013 2017 | 70/1 | 53–69 | 13 figs. | 6 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society alkali metasomatism and th-ree mineralization in the choghart deposit, bafq district, central iran khalegh khoshnoodi1,2,*, mehrdad behzadi1, mohammad gannadi-maragheh2 and mohammad yazdi1 1 university of shahid beheshti, faculty of earth science, department of geology, tehran, islamic republic of iran; (*corresponding author: khoshnoodi78@gmail.com) 2 atomic energy organization of iran, nuclear science and technology research institute, material and nuclear fnel research school, tehran, islamic republic of iran doi: 10.4154/gc.2017.03 abstract the choghart iron oxide-apatite (ioa) deposit is located 124 km southeast of yazd, in the bafq district within the central iranian microcontinent. the choghart deposit is hosted by the rhyolitic rocks of the early cambrian volcano-sedimentary sequence (the esfordi formation). both host rocks and the orebodies are crosscut by diabase dykes. tectonically, the choghart rhyolites represent the continental margin setting and the choghart diabase dykes formed in the back-arc basin environment, respectively, indicating that the evolution of the bafq district is associated with subduction of palaeotethys oceanic crust beneath the central iranian microcontinent followed by formation of continental arc related granitoids and rhyolites and then formation of backarc basin diabase dykes. similar to the other subduction-related rhyolites, the choghart rhyolite is enriched in th and lree compared to ta, nb, and hree. the main host minerals of th and ree in the th-ree mineralization zone are thorite and sphene. albitization is the most important alteration aspect related to th-ree mineralization (mainly th, la, ce, nd, and y). in addition to albite, th-ree mineralization is associated with actinolite, augite, diopside, minor microcline and orthoclase, plus magnetite, calcite, pyrite, rutile, and minor amounts of chalcopyrite. the negative eu anomaly in th mineralization zone, as well as the paragenetic occurrence of magnetite, pyrite and chalcopyrite with thorite suggest that th-ree mineralization formed in relatively reduced condition. the presence of paragenetic calcite accompanied by thorite and sphene in the th-ree mineralization zone indicates that th and ree were likely transported by the carbonate complexes in the mineralizing fluids. the similarity between the chondrite-normalized ree patterns of the host rhyolite and the th-ree mineralization zone suggests that post-magmatic driven fluids of continental margin rhyolitic magma played an important role in th-ree mineralization. 1. introduction the choghart iron oxide-apatite (ioa) kiruna type deposit is situated in the central lithotectonic domain of the posht-e-badam block, within the central iranian microcontinent and contains the oldest (late neoproterozoic) basement of iran. the bafq district as one of the main metallogenic provinces is in the southern section of this lithotectonic domain (figure 1a) and hosts many mineral deposits, including the iron oxide-apatite (ioa), fe-mn exhalative, and zn-pb sedimentary-exhalative (sedex) deposits. the bafq district is also recognized as the zarigan-chahmir basin, and many researchers have been studying its ore deposits (daliran, 2002; daliran et al., 2009; foster & jafarzadeh, 1994; mohammad torab, 2008, nadimi, 2007; rajabi, 2008, 2012; rajabi et al., 2012, 2015; ramezani & tucker, 2003; stosch et al., 2011; yaghubpour & mehrabi, 1997). some of the iron oxide-apatite (ioa) ore deposits of the bafq district contain ree-u-th mineralization. the bafq iron ore deposits display a range of mineralization styles including massive ore bodies, veins, stockworks and metasomatic replacements, of which their distribution is considerably different within the individual deposits (mohammad torab, 2008). the significance in the bafq district is the occurrence of th-ree (in the choghart mine) and, ree-u-th mineralization (anomaly 5 in the saghand ore field) in peripheral alteration zones around the iron ore deposits and also the correlation between the areas comprising such metals and the distribution of the alkaline metasomatic rocks. u-mo mineralization in the narigan ore deposit is possesses, genetically, a granite related origin as an exception (iaea, 2014) and it is not related to metasomatic processes (dahlkamp, 2009). metasomatic processes are proposed as performing geochemical roles in the concentration of ree-u-th bearing minerals in some areas of the world (e.g. the kirovogradkrivoi rog district of the ukraine, lagoa real in brazil and the beaverlodge district of canada, wilde (2013). na-metasomatism, among other types of metasomatic processes, are particularly effective in the concentration of such elements. this characteristic of metasomatism is marked by na-bearing minerals, which are clearly in replacement relationships with primary magmatic minerals (pirajno, 2009). the metasomatic and hydrothermal processes that occur with aqueous solutions, are the only endogenic processes in which the content of radioactive elements and primarily uranium reach economic grades titayeva (1994). the rocks affected by this type of metasomatism were first described as nagranites by tanatar (1925) or as syenites by feldman (1926). there has been a continuous interest in the association of th, u and ree mineralization, and this type of metasomatism is related to the importance of albitization in the mineralization of radioactive elements. according to kinnaird (1985), naenrichment is accompanied by concentrations of fe, u, th, zr, nb, sn, zn and hree. na-metasomatised rocks also tend to be article history: manuscript received may 23, 2016 revised manuscript accepted february 09, 2017 available online february 25, 2017 keywords: alkali metasomatism, th-ree mineralization, choghart (ioa) deposit g eo lo gi a c ro at ic a geologia croatica 70/154 enriched in rb, th, nb, la, ce, hf, zr, and y with respect to kmetasomatised rocks. the mineralization of natural radioactive elements controlled by the occurrence and development of the albitites is well studied in some localities such as the central ukraine (cuney et al., 2012) and the uranium city region in canada (dahlkamp, 1993). high-temperature hydrothermal th deposits are characterized by metasomatic replacements, accompanied by amphibolitization, aegirinization, biotitization, greisenization and filled open cavities (titayeva, 1994). obtained apatite ages confirm that ioa and the apatite-rich rocks (apatites) of the bafq district formed coevally with the early cambrian magmatic (-metasomatic) events stosch et al. (2011). alkali-metasomatism in the chogart iron oxide-apatite (ioa) deposit occurred in peripheral alteration zones of the iron orebody. it is observed by ground radiometric surveys using an rs-230 spectrometer that the radioactive anomaly of th occurs at the margin of the fe-orebody. since no previous study has worked on th-ree mineralization, the aim of this paper is to define the mineralogy of th-ree bearing mineral assemblages and the role of alteration/s and metasomatic processes in their genesis. 2. geological setting of bafq district the geological setting of the bafq district is described by rajabi et al. (2015). the crustal domain referred to as the central iranian microcontinent is a composite of three major structural zones, from e to w (alavi, 1991), the lut, tabas, and yazd blocks (figure 1a, b). the boundaries are defined by regionalscale faults (figure 1). in addition, there is the posht-e-badam block (alavi, 1991), a fault-bound, variably deformed and metamorphosed complex of supracrustal rocks that separates the tabas and yazd blocks (figure 1). the posht-e-badam block represents the area surrounded by three major fault systems (alavi, 1991) including the chapedony, kalmard and kuhbanan faults. a precambrian crystalline basement and early cambrian to tertiary sedimentary cover are exposed in the block (foster & jafarzadeh, 1994). the precambrian basement consists of mediumto highgrade metamorphic rocks, late neoproterozoic in age, grouped in the boneh-shurow and posht-e-badam complexes (figure 2; rajabi, 2008; ramezani & tucker, 2003). the bulk of the posht-e-badam complex consists of a variable association of greenstones, schists, meta-greywackes, marbles, gneisses, amphibolites, pyroxenites, serpentinites, meta-basalts and conglomerates (haghipour & pelissier, 1968). this complex is ex posed west of the posht-e-badam fault (figure 2) and is severely disrupted by granitic plutons of triassic age (ramezani & tucker, 2003). the boneh-shurow complex, which is the most widely exposed metamorphic unit, crops out east of the poshte-badam fault (figure 2; haghipour & pelissier, 1968). this complex is approximately 2000 m thick and is composed of a variety of metamorphic rocks, including quartz-feldspathic gneisses, green mica-schists and amphibolites (aghanabati, 2008). zircon u/pb dating of this complex indicates an age of 602–617 ma (ramezani & tucker, 2003). the bonehshurow complex is covered by a 2000-m-thick sequence of greywackes, quartzites and quartzitic schists, marbles, amphibolites, gneiss, slaty-shales, basaltic lavas, sandstones and arkosic arenites, argillites, tuffaceous rocks and limestones belonging to the tashk formation, of late neoproterozoic to early cambrian age, figure 1. (a) simplified structural map of iran (aghanabati, 1998) and location of the bafq district in the posht-e-badam block; (b) eastern part of the terranes map of the western tethysides (rajabi et al., 2012; modified by after stampfli, 2009; according to bagheri & stampfli, 2008). note the location of the iran plate (iranian cimmerian terranes) between the variscan domain in the north and the arabian plate in the southwest (ztz: zagros thrust zone). g eologia c roatica khoshnoodi et al.: alkali metasomatism and th-ree mineralization in the choghart deposit, bafq district, central iran 55 (ramezani & tucker, 2003) that partly metamorphosed to greenschist facies. during the early cambrian, granitic plutons intruded the precambrian sequence of the tashk formation, and felsic to intermediate volcanic and volcano-sedimentary rocks of the early cambrian volcano-sedimentary sequence (ecvss) were deposited. the 2000-2500 m thick ecvss unconformably overlies the clastic sedimentary and tuffaceous rocks of the tashk formation. this contact is well exposed to the w and sw of the narigan area. the ecvss has also been termed the cambrian volcano-sedifigure 2. simplified geological map of the bafq district in the posht-e-badam block, (modified after haghipour, 1977; kargaranbafghi et al., 2012; ramezani & tucker, 2003; rajabi et al., 2015). geochronological data from ramezani & tucker (2003) and kargaranbafghi et al. (2012). g eo lo gi a c ro at ic a geologia croatica 70/156 mentary unit (cvsu), rizu-desu series and esfordi formation, in different places between the posht-e-badam and kerman areas (haghipour, 1977; huckriede et al., 1962; ramezani & tucker, 2003; samani, 1993). the ecvss consists of an unmetamorphosed sequence of interlayered micro-conglomerates, sandstones, mafic to felsic volcanic rocks, pyritic black siltstones and shales, volcanoclastic beds and tuffaceous shales, dolomites and dolomitic limestones (huckriede et al., 1962; rajabi, 2012; ramezani & tucker, 2003). this sequence is the host of the most important iron oxide-apatite (ioa) (daliran, 2002), fe-mn and sedex zn-pb deposits of iran (figure 2). iron oxide-apatite (ioa) deposits, often referred to as figure 3. (a) simplified geological map of the ore body of the choghart deposit (pit face, 2011; modified after dehghan, 2011); (b) simplified geological cross section of the choghart deposit (modified after foster & jafarzadeh, 1994). khoshnoodi et al.: alkali metasomatism and th-ree mineralization in the choghart deposit, bafq district, central iran 57 g eologia c roatica kiruna-type iron ore deposits, are known to have formed from the proterozoic to the tertiary. they are commonly associated with calc-alkaline volcanic rocks and regionalto deposit-scale metasomatic alteration (stosch et al., 2011). 3. geology of the choghart deposit the main roughly vertical, discordant, pipe-shaped magnetite apatite orebody at choghart, plunging 73°nnw, has been explored to a depth of 600 m, where it seems to interfinger with intrusive metasomatized and fragmented wall-rock. the thickness of the metasomatic zone differs widely. the orebody is hosted by volcanic members (rhyolitic to rhyodacitic in composition, as well as so-called quartz albitophyre) of the infracambrian esfordi formation (moore & modabberi, 2003). it is enveloped by metasomatic rocks with variable thickness. the ore body is crosscut by both diabase dykes and n-s trending normal faults. the iron concentration is not uniform throughout the ore body: the fe content in the centre of the deposit is greater than 65% whereas it decreases to 45–20% towards the margins (moore & modabberi, 2003). the ore body is mostly surrounded by sodic-calcic hydrothermally altered rocks (figure 3a, b), with minor albitite (5–30 cm wide). the p2o5 content is very low (<0.2%) and it is enriched in the n-ne of the deposit. n-s, nw-se and ne-sw trending normal faults cut each other and the ore body. the most well-known outstanding feature is the voluminous district-scale sodic-calcic alteration that developed in volcanic hostrocks. the na-ca alteration is enveloped as actinolite, apatite, magnetite, haematite, sodic plagioclase, chlorite, with or without epidote. within the pervasively na-ca altered rhyolite and volcanoclastic rocks, there are locally patches with intense na alteration with veins and veinlets of albite and a brecciated texture (taghipour et al. 2013). apatite is the most abundant gangue at choghart. it is a distinctive, transparent, yellow-green fluor-apatite. fine and coarse-grained apatite occur in table 1. major and trace elements (ree, hfse, lile) of the felsic and basic rocks of the bafq district (major oxides in percent and minor and trace elements in ppm; rhy: rhyolite, dia: diabase, rhyd: rhyodacite, dac: dacite). detection limit for major and minor elements <10 ppm and for trace element < 0.1 ppm.*r= rajabi et al., 2015; r&t= ramezani & tucker, 2003; kh= our research; m: mirzaei beni, 2014; mt= mohammad torab, 2008 sample rock ref.* locality sio2 tio2 al2o3 feot mno mgo cao na2o k2o es7 rhy mt esfordi 73.08 0.212 11.64 1.575 0.024 0.21 0.478 0.26 8.465 es9 rhy mt esfordi 72.22 0.35 15.02 0.972 0.007 1.31 0.228 0.22 4.906 b3-s1 rhy mt esfordi 61.95 0.103 10.49 2.952 0.023 7.75 3.62 0.27 6.456 b35-s1 rhy mt esfordi 63.29 0.145 9.72 2.979 0.017 8.55 3.424 0.44 5.254 b43-s1 rhy mt esfordi 62.82 0.205 10.43 4.869 0.041 5.05 3.886 0.34 6.059 ma1 rhy mt chador-malu 65.94 0.213 10.77 5.49 0.059 0.93 1.834 0.27 8.894 ry-1 rhy m se-chahun 77.17 10.98 2.14 0.7 0.73 4.76 3.32 ry-2 rhy m se-chahun 78.35 9.03 3.15 2.6 0.52 2.07 3.88 ry-3 rhy m se-chahun 74.15 11.81 2.7 0.9 1.5 5.13 3.58 ry-4 rhy m se-chahun 76.66 9.9 3.4 2.81 0.58 2.35 3.9 6 dia r chahmir 47.61 3.7 16.14 12.82 0.19 6.37 4.78 4.29 2.01 7 dia r koushk 46.75 3.29 15.75 13.89 0.3 6.4 4.88 4.1 2.29 9 dia r narigan 51.73 2.37 13.76 11.26 0.21 7.89 7.49 2.9 0.77 10 dia r narigan 52.53 2.25 13.39 11.03 0.2 7.76 7.34 3.09 0.8 16 dia j narigan 44 3.21 13.35 12.83 0.14 8.62 6.16 3.53 1.51 21 rhy r&t duzakh-darreh 79.06 0.24 11.95 0.13 0.01 0.19 0.45 6.22 1.46 22 dac r&t chahgaz 67.05 0.81 13.23 6.48 0.05 0.74 1.76 6.48 1.7 26 rhyd r narigan 72.62 0.24 13.66 1.59 0.12 0.16 1.7 3.07 6.62 27 rhyd r narigan 73.97 0.21 12.68 1.43 0.11 0.19 1.48 3.38 6.34 28 rhy r koushk 74.81 0.24 11.51 2.55 0.03 0.54 1.16 0.21 8.64 29 rhy r koushk 70.59 0.27 13.2 3.84 0.08 0.51 1.32 0.3 9.34 31 rhy r chahmir 71.21 0.21 12.51 3.2 0.51 0.5 1.12 0.31 9.16 32 rhy r chahmir 73.8 0.2 13.14 1.83 0.04 0.56 1.01 0.23 8.59 38 rhy r chahmir 78.38 0.16 10.9 1.2 0.03 0.52 1.44 4.63 2.37 45 dia r zarigan kh-001 dia kh choghart 54.35 1.43 9.04 9.50 0.03 7.56 1.12 0.76 1.98 kh-008 dia kh choghart 53.5 2.15 14.26 14.85 0.12 6.63 8.39 2.52 2.00 kh-009 rhy kh choghart 78.37 0.11 13.32 4.31 0.012 3.81 1.95 4.82 1.55 kh-010 rhy kh choghart 83.06 0.22 6.39 1.69 0.006 0.08 0.42 6.30 0.91 kh-011 rhy kh choghart 83.45 0.22 7.10 2.84 0.004 0.44 0.66 6.67 0.90 kh-059 rhy kh choghart 81.08 0.21 12.72 1.93 0.008 0.86 1.25 6.55 1.51 kh-071 dia kh choghart 55.81 4.36 15.58 13.96 0.1 7.58 10.12 4.28 1.83 kh-072 rhy kh choghart 82.5 0.21 14.52 2.55 0.019 0.90 1.88 7.86 0.41 kh-096 rhy kh choghart 83.43 0.16 9.83 1.09 0.015 0.46 0.74 7.06 0.97 kh-097 rhy kh choghart 83.92 0.22 12.56 1.54 0.007 0.20 0.57 7.51 0.81 kh-098 rhy kh choghart 80.61 0.33 13.45 2.21 0.005 0.45 0.61 7.25 1.20 kh-099 rhy kh choghart 82.63 0.21 12.32 1.36 0.014 0.08 2.39 7.65 0.16 kh-100 rhy kh choghart 83.22 0.25 12.01 1.48 0.004 0.40 0.40 6.60 1.27 kh-101 dia kh choghart 48.53 4.84 15.39 13.69 0.18 6.56 9.90 3.44 2.20 kh-102 dia kh choghart 54.96 3.08 17.13 13.18 0.18 4.42 7.35 5.84 1.85 g eo lo gi a c ro at ic a geologia croatica 70/158 varying proportions with magnetite, and apatite-bearing magnetite is the most abundant ore type at choghart. at least two generations of apatite are discernible. the first, which is contemporaneous with the main phase of iron oxide formation, displays euhedral crystals ranging in size from a few millimetres to a few centimetres in diameter. it is intimately intergrown with magnetite. the second generation occurs as subhedral to anhedral crystals in lenses, dykes, and veinlets of varying size and thickness, which cut the magnetite-apatite ore (moore & modabberi, 2003). pyrite and quartz are distributed quite evenly in the orebody, either as solid inclusions in primary magnetite grains or as welldeveloped crystals in the orebody and the adjacent country rock. some magnetite crystals are cemented by quartz and vice versa, indicating alternation of magnetite and quartz mineralization. calcite, dolomite, secondary haematite and talc occur throughout the orebody as veinlets and cementing material of oxidized ore. rutile and goethite are probably the result of the total transfor-the total transfor-total transformation of the earlier formed martite (moore & modabberi, 2003). the th-ree enriched zone occurs within the south-eastern margin of the fe-orebody between the f5 and f6 faults and it also cuts the sodic-calcic metasomatism/alteration as well as the host rhyolite (figure 3a). the radioactive anomaly of thorium is observed in the margin of the fe-orebody by ground radiometric and spectrometric surveys using an rs-230 spectrometer. cheman rs-230 spectrometer. chem-rs-230 spectrometer. chemical analyses of samples of this zone show th-ree mineralization.the hydrothermal breccia and albitization (pink in colour), are both associated with th-ree mineralization shown in figure 4a, b. carbonate-silica veins and veinlets cross cut the host rock, the fe-orebody and th-ree mineralization zone which indicates that they are formed after the th-ree mineralization. 4. material and methods thirty-five samples were collected for petrographic, ore microscopic and geochemical studies from the th-ree mineralization table 1. continued sample p2o5 la ce pr nd sm eu gd tb dy ho er tm es7 0.022 30.3 57 <50 17 2.5 0.7 <0.5 es9 0.072 1.4 5 <50 <5 0.4 <0.2 <0.5 b3-s1 0.626 129 221 <50 106 16.1 2.1 2.3 b35-s1 1.071 147 324 57 108 20.9 3.1 2.8 b43-s1 0.487 71 138 <50 60 11.3 1.4 1.7 ma1 0.056 34.2 105 <50 43 12.9 2 1.8 ry-1 0.03 40.5 73.65 9.8 34.2 7.1 1.3 5.3 0.8 4.3 0.8 2.1 0.3 ry-2 0.06 38.4 67.14 8.7 29.7 6 1.1 4.4 0.9 4.1 0.8 2 0.3 ry-3 0.05 39.5 70.54 9.16 31.59 6.58 1.21 4.84 0.88 4.63 0.88 2.25 0.32 ry-4 0.05 36.2 64.64 8.39 28.93 6.03 1.11 4.44 0.81 4.26 0.81 2.07 0.29 6 0.61 33 65.2 7.7 32.2 7.8 2.6 7.8 1.1 5.6 1 2.5 0.3 7 0.8 30.1 63 7.5 30 7.7 2.5 7.7 1 5.4 0.9 2.3 0.3 9 0.34 22.7 49.9 6.6 27.3 6.5 2.1 6.4 1 5.3 1 2.5 0.4 10 0.37 24.1 52 6.7 29 7 2.2 6.4 1 6 1.1 3 0.4 21 0.08 30.2 57.2 6.3 22.4 4.1 0.9 0.7 22 0.21 57.8 135.2 16.7 67 17.8 3.9 3.3 26 0.05 9.2 19.1 2.3 8.5 1.7 0.3 1.8 0.3 2.1 0.5 1.6 0.3 27 0.05 9 17 2.1 7 1.5 0.2 1.5 0.3 1.8 0.4 1.3 0.2 28 0.03 20.9 43 4.9 17.5 3.4 0.7 4.9 1 7.5 1.8 5.8 0.9 29 0.1 17 38 4.8 15 3.1 0.6 4.5 0.9 7.3 1.7 5.3 0.9 31 0.88 14 31 4.3 13 3 0.6 4.1 0.8 5.5 1.5 5.1 0.7 32 0.4 11 27 3.9 11 2.8 0.5 3.9 0.7 5 1.3 4.9 0.6 45 56.3 113 13.3 48.1 8.9 2.8 6.9 1 5 0.9 2.3 0.3 kh-001 0.32 31.25 65.52 8.06 37.30 5.04 2.02 5.04 0.91 3.02 0.50 2.02 0.30 kh-008 0.45 27.86 65.02 7.22 37.15 7.22 2.06 7.22 0.93 4.13 0.83 2.06 0.31 kh-009 0.02 8.92 30.72 2.97 1119.8 1.98 0.30 1.98 0.30 1.98 0.59 1.98 0.30 kh-010 0.03 0.71 2.04 0.31 1.02 0.20 0.08 0.31 0.10 0.51 0.10 0.20 0.08 kh-011 0.02 1.07 3.20 0.32 2.13 0.53 0.11 3.20 0.08 0.43 0.08 0.53 0.11 kh-059 0.01 23.23 62.62 5.05 27.27 1.01 0.40 4.04 0.20 2.02 0.51 1.01 0.10 kh-071 0.54 5.90 10.82 0.98 5.90 0.98 0.39 1.97 0.20 0.98 0.20 0.98 0.10 kh-072 0.01 71.86 159.68 18.96 99.80 14.97 4.99 19.96 2.00 7.98 2.00 3.99 0.50 kh-096 0.01 6.97 10.95 1.99 5.97 1.00 0.40 1.00 0.10 0.40 0.10 0.50 0.10 kh-097 0.01 5.95 9.92 0.99 4.96 0.99 0.40 0.69 0.10 0.50 0.10 0.30 0.10 kh-098 0.00 2.94 4.91 0.98 4.91 0.98 0.39 1.96 0.20 1.96 0.29 0.98 0.10 kh-099 0.00 2.90 4.84 0.58 3.87 0.97 0.39 1.93 0.19 0.97 0.19 0.87 0.19 kh-100 0.01 2.96 7.88 0.99 3.94 0.39 0.10 0.59 0.10 0.49 0.10 0.39 0.10 kh-101 0.40 52.31 110.66 12.07 51.31 8.05 3.02 10.06 1.01 8.05 1.01 4.02 0.50 kh-102 1.03 79.70 174.96 15.55 71.93 12.64 4.86 14.58 0.97 6.80 0.97 2.92 0.10 g eologia c roatica khoshnoodi et al.: alkali metasomatism and th-ree mineralization in the choghart deposit, bafq district, central iran 59 table 1. continued sample yb lu nb ta zr hf nb ta pb y zr th u es7 2 0.44 4 <0.5 188 5 .375 <0.5 <3 9 188 19.5 6.8 es9 0.9 0.25 6 <0.5 227 5 .375 <0.5 <3 <3 227 2.5 1.5 b3-s1 5.8 0.86 <2 <0.5 181 6 .375 <0.5 <3 47 181 14.9 1.2 b35-s1 7.7 1.16 2 <0.5 195 4 .375 <0.5 <3 124 195 14.9 1.9 b43-s1 6.1 0.91 <2 <0.5 175 5 .375 <0.5 3 54 175 18.8 4.7 ma1 3.2 0.41 <2 0.6 159 5 .6 0.6 11 38 159 6 1.5 ry-1 2 0.4 3.07 0.4 58.6 2.35 .4 0.4 1.43 21.2 58.6 12.3 2.1 ry-2 2.1 0.3 5.18 0.4 62.8 2.27 .4 0.4 2.2 24.3 62.8 10.2 2.1 ry-3 2 0.3 4.1 0.4 60.2 2.29 .4 0.4 1.8 22.3 60.2 11.8 2.1 ry-4 2 0.4 4.9 0.4 59.1 2.32 .4 0.4 2.1 23.9 59.1 10.7 2.1 6 1.9 0.2 52.2 3.3 252 6.4 3.3 3.3 45 27.1 252 4.3 1.3 7 1.9 0.2 47 3.1 245 6.1 3.1 3.1 40 25 245 4.2 1.2 9 2 0.3 26 1.8 211 6 1.8 1.8 25.1 211 3.2 0.8 10 2.1 0.4 29 1.9 215 7 1.9 1.9 26 215 3.5 0.9 21 2.5 0.4 2.4 0.4 125 3.5 .4 0.4 26 125 5.8 2.3 22 13.7 2.1 22.7 1.6 850 23 1.6 1.6 114 850 8.4 2.4 26 1.8 0.3 5 0.5 116 4 .5 0.5 13.3 116 8.4 2.1 27 1.7 0.2 4.8 0.5 109 3 .5 0.5 13 109 8.2 2 28 5.8 0.9 5 0.6 172 5 .6 0.6 54.8 172 11.6 2.4 29 5.5 0.8 4.8 0.6 165 4.5 .6 0.6 51 165 11.3 2.4 31 4.5 0.7 3 0.5 158 4.2 .5 0.5 49 158 11 2.3 32 3.7 0.6 3 0.5 160 3.9 .5 0.5 47 160 11.1 2.3 45 1.9 0.3 125 8.1 262 6 8.1 8.1 21.1 262 9.7 3.7 kh-001 2.02 0.30 36.29 2.02 141.12 3.02 2.02 2.02 3.02 17.14 141.12 16.13 82.66 kh-008 2.06 0.21 39.22 2.06 144.48 2.06 2.06 2.06 4.13 20.64 144.48 3.10 5.16 kh-009 1.98 0.40 1.98 0.69 138.74 2.97 .69 0.69 1.98 15.86 138.74 21.80 2.97 kh-010 0.41 0.10 3.06 0.61 122.28 2.04 .61 0.61 2.04 1.02 122.28 4.08 2.04 kh-011 0.43 0.11 2.13 0.21 117.37 2.13 .21 0.21 2.13 2.13 117.37 4.27 1.07 kh-059 2.02 0.30 6.06 0.51 161.60 4.04 .51 0.51 5.05 12.12 161.60 40.40 11.11 kh-071 1.97 0.20 3.94 0.30 118.08 2.95 30 0.30 2.95 8.86 118.08 17.71 2.95 kh-072 2.00 0.30 109.8 2.99 199.60 2.99 2.99 2.99 3.99 33.93 199.60 7.98 2.00 kh-096 0.50 0.10 0.50 0.10 139.30 0.90 .10 0.10 1.00 2.99 139.30 3.98 1.00 kh-097 0.50 0.10 1.98 0.20 119.04 1.98 .20 0.20 2.98 3.97 119.04 10.91 1.98 kh-098 1.96 0.10 1.96 0.29 147.15 1.96 .29 0.29 3.92 6.87 147.15 12.75 1.96 kh-099 0.97 0.10 1.93 0.10 116.04 1.93 .10 0.10 1.93 6.77 116.04 12.57 1.93 kh-100 0.59 0.10 1.97 0.20 137.90 1.97 .20 0.20 1.97 1.97 137.90 9.85 0.99 kh-101 3.02 0.20 45.27 0.91 140.84 2.01 .91 0.91 3.02 130. 8 140.84 4.02 1.01 kh-102 0.97 0.10 54.43 0.97 320.76 2.92 .97 0.97 4.86 25.27 320.76 4.86 1.94 figure 4. (a) th-ree mineralization within hydrothermal breccia; (b) hand specimen of pinkish albitite including th-ree mineralization. g eo lo gi a c ro at ic a geologia croatica 70/160 zone (20 samples), volcanic host rock (10 samples) and diabase dykes (5 samples) at the choghart deposit. the whole-rock concentrations of major oxides and trace elements were determined by inductively coupled plasma (icp) optical emission spectroscopy (oes) and mass spectrometry (ms) at the jaber-ebnehayyan laboratory of nuclear science and technology research institute in tehran, iran. the detection limit for the main oxides and also the minor elements by icp-oes is <10 ppm, and for the trace elements by icp-ms is < 0.1 ppm. in addition, the data obtained from previous studies in the bafq district were also used to strengthen the discussion of results obtained from the present study (table 1; ramezani & tucker, 2003; mohammad torab, 2008; mirzaei beni, 2014; rajabi, et al., 2015). petrographic and ore microscopic studies (including general recognition of mineral assemblages, alteration, metasomatic replacements and textures) were performed using an olympus bx60 microscope at the petrography laboratory at the shahid beheshti university of tehran. based on optical microscope observations, 12 th-ree mineralized thin-polished sections were selected for electron probe micro-analysis (epma). the detailed study of mineral assemblages, alteration, metasomatic replacements and textures was carried out at the mineralogy division of the iranian mineral processing research centre (imprc) using a cameca sx-100 electron microprobe equipped with 5 wavelength-dispersive crystal spectrometers. measurements were performed using an accelerating voltage of 15 kv, a beam current of 20 na, beam size of ~5 µm and 15s counting time for major elements and an accelerating voltage of 25 kv, a beam current of 20 na, beam size of ~3 µm and 30s counting time for trace elements. natural oxides and silicates were used as standards and for calibration. raw data were corrected for matrix effects with the zaf correction procedure implemented by cameca. 5. results and discussion 5.1. geochemistry of host rocks and mineralization the rare earth elements (ree), high-field-strength elements (hfse), th and transition elements are usually immobile during intense hydrothermal alterations. in addition, the hydrothermal fluids do not have a great capacity to transport some of the major elements such as ti and p (e.g. zhou, 1999). in contrast, mg, ca, mg, na, k, and some of the large ion lithophile elements (lile; e.g. sr, ba and rb) are mobile under hydrothermal conditions (e.g., mobility smith & smith, 1976). immobile trace element geochemistry (including ree) is utilized here to deduce the tectonic setting of the igneous rocks. figure 5. log (nb/y) versus log (zr/tio2) plot of winchester & floyd (1977) (a) for pyroclastic and effusive rocks; (b) for diabase dykes of the choghartbafq district; (c) diagram of th/hf vs. ta/hf ratios for felsic rocks; (d) the log (ce/nb) versus log (th/nb) plot of saunders & tarney (1991) for diabase rocks. g eologia c roatica khoshnoodi et al.: alkali metasomatism and th-ree mineralization in the choghart deposit, bafq district, central iran 61 figure 6. shows the chondriteand primitive-mantle-normalized ree patterns. the patterns for basaltic rocks (figure 6a, b) display significant variation from lree to hree, similar to oceanic-island basalts (oib). most ree patterns of felsic rocks display enrichment in the lree, with relatively flat hree patterns (figure 6c). rhyolitic rocks of the bafq district are noticeably enriched in th and depleted in ta, nb and ti (figure 6d). because the mantle was progressively modified by subducted oceanic crust, felsic volcanic rocks became enriched in th and lree compared to ta, nb, and hree (schandl & gorton, 2002). the primitive-mantle-normalized geochemical patterns, arranged in order of incompatibly elements, indicate that the basaltic rocks of the bafq district are more lreeand hfse (th, nb, ta, zr, hf)-enriched rather than e-morb or n-morb (figure 6d). considering the afore mentioned context, the choghart rhyolite is similar to other felsic volcanic rocks and ecvss granites formed in a continental margin setting, and like other continental margin rocks are noticeably enriched in th and lree compared to ta, nb, and the heavy rare earth elements. likewise, the diabase dykes of choghart have alkaline compositions similar to other diabase dykes and mafic rocks of the early cambrian volcano-sedimentary sequence and were formed in a back-arc basin environment. based on the results obtained during the study, the evolution of the bafq district is genetically, related to the subduction of palaeotethys oceanic crust beneath the central iranian microcontinent followed by formation of continental arc granitoids and rhyolites and then formation of back-arc basin diabase dykes (rajabi et al., 2015). diabase dykes were formed in a back-arc extensional setting after magnetite-apatite and th-ree since the volcanic host rocks of the choghart deposit are affected by hydrothermal alteration, the immobile elements are employed for petrogenetic interpretations of the rhyolites in the bafq district (chahmir, koushk, se-chahun, choghart, etc.). on the log (zr/tio2) vs. log (nb/y) plot of winchester & floyd (1977), effusive rocks range from rhyolite to dacite in composition (two samples of choghart lie within trachy-andesite field), and the samples of diabase dykes from the bafq district plot within the alkaline basalt field (two samples of choghart plot within the basalt field) (figure 5a, b). hfse ratios in felsic volcanic rocks reflect the regional tectonomagmatic evolution. th/ta, th/hf, ta/hf, th/yb, and ta/yb ratios help to define the tectonic setting of volcanism, separating oceanic arcs, active continental margins, and within-plate volcanic zones (schandl & gorton, 2002). the rhyolites of the bafq district particularly choghart are enriched in th and the light rare earth elements compared to ta, nb, and the heavy rare earth elements that are related to subduction zones. variable th/ta ratios within individual deposits show fractionation trends (figure 5c; schandl & gorton, 2002). the ce/nb vs. th/nb plot of saunders & tarney (1991) is useful in discriminating the tectonic environment of mafic rocks, because these elements are immobile during alteration processes. the diabase dyke samples of the bafq district plot in the field of within-plate basalts (wpb); except for two samples of choghart that plot out of this field in the field of continental margin volcanic arc basalt. this is possibly because of high con-. this is possibly because of high conthis is possibly because of high concentrations of th (figure 5d). furthermore, th and ta behave coherently in non-subduction-related basalts, decoupling only in the subduction environment (wood, 1980). figure 6. chondrite and primitive mantle normalized rare earth elements and incompatible elements distribution patterns (spider diagrams) (sun and mc  donough, 1989) for the bafq district (a, b) diabase dykes and (c, d) rhyolitic rocks g eo lo gi a c ro at ic a geologia croatica 70/162 mineralization in the choghart deposit. the k2o vs. na2o diagram (figure 7a) illustrates that all th-ree mineralized samples lie within the high-na field. this diagram indicates that in the choghart th-ree mineralization zone the sodic alteration occurred pervasively. the chondrite-normalized ree patterns (fig. 7b) of th-mineralization zone samples show a weak lree/hree fractionation and pronounced negative eu anomaly. in addition, the similarity between the chondrite-normalized ree patterns of the rhyolites and th-mineralization zone in the choghart mine is obvious. the negative eu anomaly in the th-mineralization zone of choghart could be inherited from the fluid source. this implies that the fluid originated from rocks in which plagioclase has removed eu2+ or equilibrated with them, because eu2+ substitutes for ca2+ in plagioclase, early crystallizing plagioclase in magma will remove eu2+ from the system and thus a later exsolving fluid will be depleted in eu. additionally, if a fluid equilibrates with a plagioclase-bearing rock and doesn’t dissolve plafigure 7. (a) the k2o vs. na2o diagram for th-ree mineralized samples; (b) comparison of chondrite-normalized ree patterns of the choghart rhyolite and the th-ree mineralization zone. figure 8. (a) photomicrograph (transmitted-light) of thorite associated with actinolite and calcite; (b) photomicrograph (reflected-light) of thorite accompanied by magnetite, pyrite and chalcopyrite; (c) bse image; conversion of ilmenite to sphene and rutile and also to rutile and titanomagnetite (th: thorite, act: actinolite, ilm: ilmenite, ab: albite, py: pyrite, tim: titanomagnetite, ccp: chalcopyrite, cal: calcite, mag: magnetite, sph: sphene, rut: rutile, kfd: k-feldspar). g eologia c roatica khoshnoodi et al.: alkali metasomatism and th-ree mineralization in the choghart deposit, bafq district, central iran 63 gioclase, then the depletion in eu will be inherited by the fluid. the negative eu anomaly may reflect reducing conditions of the mineralizing fluid and depositional environment. beside the redox conditions, the eu2+/eu3+ ratio can be controlled by temperature (bau & möller 1992). since paragenetic magnetite, pyrite and chalcopyrite in mineral assemblages of the th-mineralization zone were observed, the negative eu anomaly is most likely due to the reducing conditions of the mineralizing fluid and depositional environment. according to figure 7b, the chondritenormalized ree patterns of the choghart rhyolite and th-ree mineralization zone are similar, suggesting that th and ree origi nated from continental margin choghart rhyolitic magma. 5.2. mineralogy the microscope studies indicated that the main th mineral in th-ree mineralization zone is thorite (figure 8a, b) which occurs in veinlets, either disseminated or as inclusions in other minerals such as albite and clinopyroxene. minor amounts of thorite are associated with the sodic-calcic altered magnetite ore body. sphene is the other host mineral of ree but is quantitatively less important than thorite. two generations of sphene are recognized; the first, primary sphene which occurs as individual crystals and was likely precipitated directly from the mineralizing fluids (figu re 9a), and the second generation of sphene that formed by alteration of ilmenite (figure 8c). calciumand silica-rich mineralizing fluids cause the alteration of ilmenite that is converted to sphene and rutile. iron released from ilmenite alteration precipitated as magnetite (figure 8c). in some microscope sections, ilmenite is observed to be converted to rutile and titanomagnetite (figure 8c). formation of magnetite, sphene and rutile suggests that probably the temperature of mineralizing fluids was relatively high. the occurrence of magnetite as a fracture filling in thorite indicates that it precipitated after thorite formation. the silicate minerals accompanied by th-ree mineralization include albite, amphibole and pyroxene. following the nomenclature of leake et al. (1997) and epma analyses (table 2), figure 9. (a) bse image; primary sphene as an individual crystal; (b) photomicrograph (reflected-light) of the first generation of paragenetic galena with th-ree mineralization; (c) bse image; the second generation of galena formed after th-ree mineralization as fracture filling of thorite (th: thorite, ccp: chalcopyrite, mag: magnetite, sph: sphene, rut: rutile, aug: augite, gn: galena). figure 10. classification of the calcic amphiboles in the th-ree mineralization zone of choghart. g eo lo gi a c ro at ic a geologia croatica 70/164 the amphibole belongs to the calcic group and is actinolite (except for 2 points which fall in the tremolite field, figure 10). according to the nomenclature of morimoto et al. (1989) and epma analyses (table 3), all pyroxenes belong to ca-rich pyroxene and fall mainly in the augite field and three samples have the composition of diopside (figure 11). also calcite, magnetite, pyrite, chalcopyrite and trace amounts of galena are associated with this type of mineralization. two generations of galena are discernible; the first is contemporaneous with th-ree mineralization (figure 9b) and the second generation of galena formed after th-ree mineralizatable 3. representative electron microprobe analyses of pyroxene in some studied samples, detection limit < 0.01%. px1 px2 px3 px4 px5 px6 px7 px8 px9 px10 px11 px12 px13 px14 px15 sio2 56.83 54.26 54.73 57.12 56.41 54.23 55.65 58.14 55.62 57.23 56.74 58.38 57.26 58.01 58.09 tio2 0.00 0.13 0.13 0.00 0.02 0.05 0.00 0.01 0.13 0.02 0.04 0.17 0.21 0.29 0.24 al2o3 0.47 0.3 0.36 0.24 0.15 0.2 0.77 0.66 0.39 0.27 0.52 1.05 1.01 1.16 1.09 fe2o3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 cr2o3 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.01 0.02 0.00 0.00 0.00 0.00 0.00 feo 11.79 6.77 6.92 6.01 5.87 7.19 19.3 9.72 6.53 12.74 13.58 7.18 8.06 6.22 7.53 mno 0.13 0.1 0.13 0.12 0.11 0.11 0.59 0.31 0.12 0.28 1.6 0.12 0.08 0.07 0.1 mgo 17.5 14.48 14.69 15.27 15.1 13.97 10.63 18.06 15.91 16.08 14.43 20.6 19.59 21.82 20.43 cao 11.64 22.05 21.9 21.41 22.77 22.76 8.69 12.72 20.9 12.89 11.87 12.54 12.37 11.42 12.28 na2o 0.24 1.07 1.14 0.58 0.31 1.01 2.43 0.14 1.04 0.07 0.68 0.6 0.28 1.44 0.66 k2o 0.02 0.02 0.00 0.00 0.00 0.01 0.09 0.03 0.00 0.00 0.06 0.17 0.19 0.36 0.18 total 98.62 99.18 100.0 100.8 100.8 99.53 98.15 99.79 100.7 99.6 99.52 100.8 99.05 100.8 100.6 formulae based on 4 cations and 6 oxygens si 2.136 2.014 2.014 2.089 2.068 2.012 2.157 2.150 2.025 2.152 2.147 2.097 2.108 2.056 2.092 ti 0.00 0.004 0.004 0.00 0.001 0.001 0.00 0.00 0.004 0.001 0.001 0.005 0.006 0.008 0.007 al 0.021 0.013 0.016 0.01 0.006 0.009 0.035 0.029 0.017 0.012 0.023 0.044 0.044 0.048 0.046 fe3+ 0.00 0.03 0.031 0.00 0.00 0.037 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 cr3+ 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.001 0.00 0.00 0.00 0.00 0.00 fe2+ 0.371 0.18 0.181 0.184 0.18 0.186 0.626 0.301 0.199 0.401 0.43 0.216 0.248 0.184 0.227 mn 0.004 0.003 0.004 0.004 0.003 0.003 0.019 0.01 0.004 0.009 0.051 0.004 0.002 0.002 0.003 mg 0.981 0.801 0.806 0.833 0.825 0.773 0.614 0.996 0.863 0.901 0.814 1.103 1.075 1.153 1.097 ca 0.469 0.877 0.863 0.839 0.894 0.905 0.361 0.504 0.815 0.519 0.481 0.483 0.488 0.434 0.474 na 0.017 0.077 0.081 0.041 0.022 0.073 0.183 0.01 0.073 0.005 0.050 0.042 0.02 0.099 0.046 k 0.001 0.001 0.00 0.00 0.00 0.00 0.004 0.001 0.00 0.00 0.003 0.008 0.009 0.016 0.008 sum 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 table 2. representative electron microprobe analyses of amphibole in some studied samples, detection limit < 0.01%. am1 am2 am3 am4 am5 am6 am7 am8 am9 am10 am11 am12 am13 sio2 56.64 56.7 56.83 57.35 56.85 58.19 57.65 55.65 57.09 55.93 55.87 62.63 55.71 tio2 0.06 0.06 0.00 0.02 0.03 0.04 0.03 0.00 0.04 0.18 0.15 0.03 0.03 al2o3 0.46 1.08 0.47 0.42 0.57 0.66 1.41 0.77 0.75 0.47 0.48 0.26 0.38 fe2o3 7.58 8.08 5.46 0.03 0.00 0.00 0.00 1.78 0.00 2.97 16.16 0.00 1.32 feo 10.84 9.89 11.79 9.45 9.65 6.14 6.09 17.70 11.54 13.00 0.00 5.77 12.62 mno 0.07 0.09 0.13 0.21 0.21 0.03 0.02 0.59 0.25 0.68 0.39 0.02 0.27 mgo 18.67 19.11 17.5 18.28 17.66 19.51 19.58 10.63 16.07 13.81 16.24 27.75 14.64 cao 11.61 11.5 11.64 12.86 13.12 13.5 13.45 8.69 12.90 10.66 8.28 0.08 11.69 na2o 0.19 0.19 0.24 0.27 0.2 0.00 0.05 2.43 0.17 1.02 0.39 0.03 0.08 k2o 0.03 0.06 0.02 0.04 0.05 0.04 0.00 0.09 0.06 0.07 0.14 0.07 0.05 h2o* 2.17 2.19 2.16 2.15 2.13 2.17 2.17 2.05 2.13 2.10 2.15 2.24 2.07 total 101.5 101.68 101.32 101.06 100.48 100.28 100.45 100.38 101.0 100.88 100.25 98.9 98.9 formulae based on 16 cations and 23 oxygens si 7.818 7.771 7.794 7.999 7.991 8.046 7.959 8.125 8.035 8.000 7.791 8.368 8.064 al 0.075 0.174 0.125 0.069 0.086 0.108 0.189 0.132 0.124 0.079 0.000 0.041 0.065 ti 0.006 0.006 0.006 0.002 0.003 0.004 0.003 0.000 0.004 0.019 0.016 0.003 0.003 fe3+ 0.787 0.833 0.810 0.003 0.195 0.319 1.696 0.144 mg 3.842 3.904 3.873 3.801 3.701 4.022 4.030 2.314 3.372 2.945 3.376 5.527 3.159 fe2+ 0.464 0.301 0.382 1.100 1.134 0.710 0.703 2.161 1.358 1.555 0.000 0.645 1.528 mn 0.008 0.010 0.009 0.025 0.025 0.004 0.002 0.073 0.030 0.082 0.046 0.002 0.033 ca 1.717 1.689 1.703 1.922 1.976 2.00 1.989 1.359 1.945 1.634 1.237 0.011 1.813 na 0.051 0.050 0.051 0.073 0.055 0.00 0.013 0.688 0.046 0.283 0.105 0.008 0.022 k 0.005 0.010 0.008 0.007 0.009 0.007 0.00 0.017 0.011 0.013 0.025 0.012 0.009 oh* 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 sum 16.773 16.750 16.803 17.002 16.990 16.900 16.930 17.064 16.927 16.929 16.371 16.619 16.845 g eologia c roatica khoshnoodi et al.: alkali metasomatism and th-ree mineralization in the choghart deposit, bafq district, central iran 65 tion as a fracture filling of thorite (figure 9c). pb released from thorite (the decay product of th) probably forms the second generation of galena, provided the activity of s is sufficient. the presence of magnetite, pyrite and chalcopyrite is likely due to relatively reduced conditions in the thorite depositional environment. the paragenetic mineral assemblage of th-ree mineralization of the choghart iron oxide apatite deposit is shown in figure 12. the results of bulk chemical analyses show a high correlation of ce, la, y and nd concentrations with the th content. the empa analyses show that thorite contains mean values of 9460 ppm ce, 1950 ppm la, 1810 ppm y and 110 ppm nd (table 4). the empa analyses of sphene shows mean of 8050 ppm ce, 3650 ppm y while the contents of la and y are below the detection limit (table 5). 5.3. alkali metasomatism alkali metasomatism implies the transfer of the alkali ions, na and k, from a fluid phase, generated during the cooling of an igneous body, to the adjoining rocks. albitite, microclinite, fenites, and the core zones of potassic alteration of porphyry systems are figure 11. classification of the ca-rich pyroxene in the three mineralization zone of choghart. minerals stages pre-mineralization thorium mineraliztion last alteration o re m in er al s magnetite type i type ii thorite type i type ii titano-magnetite type i type ii ilmenite pyrite chalcopyrite galena type i type ii hematite sphene type i type ii rutile al te ra tio n m in er al s albite type i type ii diopside type i type ii augite & aegirine actinolite type i type ii calcite type i type ii type iii microcline & orthoclase quartz apatite type i type ii chlorite, talc & serpentine figure 12. the paragenetic mineral assemblage of three mineralization of the choghart deposit. g eo lo gi a c ro at ic a geologia croatica 70/166 blage (pirajno, 2013). perthite formation in the choghart th-ree mineralization zone clearly shows alkali metasomatism (figure 13a). the replacement of k by na in feldspars, probably by ion exchange, is shown by the presence of albite inclusions in the k-feldspar host. these inclusions can occur either as veinlets or irregular shapes, and do not follow crystallographic directions, as would be the case for melt-fluid unmixing (pirajno, 2013). commonly formed by alkali metasomatism. also in some cases, perthitic textures in feldspar may indicate alkali metasomatism, rather than the separation during cooling of a two-phase assemtable 4. electron microprobe analyses of thorite in some studied samples, detection limit < 0.01%. sample /element y la ce nd p ca ch-001 0.35 0.01 0.92 nd 0.18 0.96 ch-001 0.17 0.04 0.96 nd 0.19 1.07 ch-002 0.26 0.1 0.91 0.49 0.13 0.88 ch-002 0.2 0.01 0.97 0.46 0.19 1.2 ch-003 0.36 0.07 0.94 0.18 0.13 1.16 ch-003 0.14 nd 0.91 nd 0.12 1.18 ch-004 0.22 nd 0.88 0.05 0.09 0.88 ch-004 0.1 0.02 0.91 0.69 0.07 1.23 ch-005 0.16 0.04 0.9 0.12 0.16 1 ch-005 nd nd 1 0.01 0.15 0.24 ch-006 0.27 0.01 0.94 nd 0.16 1.01 ch-006 nd 0.03 0.98 nd 0.18 1.05 ch-007 0.1 nd 0.94 nd 0.14 0.98 ch-007 nd 0.04 0.93 0.02 0.17 1.12 ch-008 0.11 nd 1.03 nd 0.17 1.07 ch-008 0.03 0.01 1.01 nd 0.1 1.2 ch-009 0.54 nd 0.95 0.02 0.11 0.96 ch-009 nd nd 1 nd 0.09 1.15 ch-010 0.37 0.01 0.93 0.1 0.09 1.01 ch-010 0.24 nd 0.91 nd 0.18 0.78 table 5. electron microprobe analyses of sphene in some studied samples, detection limit < 0.01%. sample /element cao mno feo al2o3 sio2 tio2 p2o5 y ce ch-002 28.71 nd 1.26 0.74 30.36 35.04 0.03 0.23 1.08 ch-005 28.69 0.02 0.95 0.42 30.52 36.65 0.02 0.08 1 ch-007 28.93 0.03 1.37 0.11 30.55 36.35 0.03 nd 1.06 ch-008 28.55 0.01 1.36 0.62 30.35 36.83 0.01 0.15 1.08 table 6. electron microprobe analyses of thorite in some studied samples for major oxides (in percent), detection limit < 0.01%. sample /element mgo cao mno feo al2o3 sio2 tio2 p2o5 ch-001 0.05 2.06 0.08 0.37 0.04 18.21 0.12 0.28 ch-002 0.1 2.14 0.14 0.52 0.05 19.04 0.11 0.16 ch-005 nd 2.35 0.08 0.35 0.05 18.11 nd 0.58 ch-006 nd 2.46 0.05 0.3 0.06 18.4 nd 0.45 ch-009 0.01 1.29 0.08 0.47 0.06 19.19 0.01 0.6 ch-010 nd 1.3 0.1 0.43 0.02 18.32 0.04 0.43 figure 13. (a) bse image; perthite formation due to alkali metasomatism; (b) bse image; formation of albite inclusions in k-feldspar due to alkali metasomatism; (c) bse image; replacement of k-feldspar by albite (th: thorite, ab: albite, py: pyrite, di: diopside, kfd: k-feldspar). g eologia c roatica khoshnoodi et al.: alkali metasomatism and th-ree mineralization in the choghart deposit, bafq district, central iran 67 this event is clearly associated with th-ree mineralization at choghart (figure 13b). the replacement of alkali feldspar by albite (albitization or na-feldspathization) shows the more common form of sodic metasomatism. this replacement may proceed from either preexisting perthites, or direct replacement of k-feldspar with late formed albites (pollard, 1983). the replacement of k-feldspar by albite occurs pervasively accompanied with the th-ree mineralization zone at choghart (figure 13c, 4b). albitization of k-feldspar can be written as follows: kalsi3o8+na+=naalsi3o8+k+ the development of albite-rich rocks (albitites) is typically accompanied by rare element mineralization (nb, ta, sn, w, li, be). sodium-enrichment is associated with elevated concentrations of fe, u, th, zr, nb, sn, zn, and hree. na-metasomatised rocks are also more prone to be enriched in rb, th, nb, la, ce, hf, zr, and y with regard to k-metasomatised rocks (kinnaird, 1985). the choghart th-ree mineralization zone is enriched in th, la, ce, nd, and y. the high-temperature post-magmatic processes can promote the mobilization and concentration of thorium. in these processes thorium is usually associated with rare-earth elements (the lanthanides). most post-magmatic thorium-containing deposits are connected with pneumatic-hydrothermal or high-temperature hydrothermal processes. at present we know that th-ree deposits have post-magmatic genesis (titayeva, 1994). most high-temperature th-ree deposits (of pneumato-hydrothermal genesis) were formed as a result of the metasomatic replacement of country rocks. they are characterized by early albitization, k-feldspathization, aegirinization, amphibolitization, and the formation of skarn. ore minerals are niobates, tantaloand titano-niobates (euxenite, pyrochlore, priorite, fergusonite, and others), and the silicates of the rare earths, thorium, and zirconium. high-temperature hydrothermal deposits are characterized by metasomatic replacements, associated with amphibolitization, aegirinization, biotitization, greisenization, and filled open cavities. niobates, titanoand tantalo-niobates are represented here in small quantities. rare-earth phosphates (monazite and xenotime) dominate with some rare-earth silicates (orthite, cerite, britholite, etc.). the mediumand low-temperature deposits are usually veined with a characteristic change in country rocks (feldspathization, carbonatization, and silicification). ore minerals are represented by haematite, carbonates and fluorocarbonates of the rare earths (bastnaesite, parisite, synchysite, etc.), and the sulfides of fe, cu, pb, and zn (titayeva, 1994). the main paragenetic associations of thorium are the lanthanides. in high-temperature deposits th is usually associated with та, nb, ti, and occasionally with mo, w, sn, be. in moderatetemperature deposits th is paragenetically associated with pb, zn, cu. the anion components such as cl–, hco3 –, co3 2–, hs–, s2– and fare important and control the mobility of metals in post-magmatic fluids (titayeva, 1994). as mentioned above the th-ree mineralization zone (thorite and sphene) in choghart is associated with albitization, amphibolitization (actinolite), pyroxenitization (augite and diopside), carbonatization and minor k-feldespatization (microcline), as well as the occurrence of pyrite and minor amounts of chalcopyrite, considered to be a moderate-temperature post-magmatic three mineralization type. 5.4. mineral formation conditions thermodynamic calculations have indicated that fluoride or mixed carbonate-fluoride complexes can dominate ree speciation (e.g., wood, 1990a, b). the scarcity of the f-bearing ree minerals (f lourapatite) in the th-ree mineralized zone of choghart, however, implies that a high concentration of fluorine was probably, only locally, achieved and is not necessarily a component of the composite ore-forming fluids. the presence of calcite along with calcic– amphibole and – pyroxene (actinolite and augite, respectively), the high content of ca in thorite (table 6; up to 2.3% cao) and the occurrence of sphene in the choghart th-ree mineralization zone imply that thorite crystallized from a ca2+and co3 2–bearing aqueous solution under conditions of low activity of f–. considering that dolomitic xenolites of the esfordi formation are observed in the volcanic host rocks of the choghart deposit, the portion of co2 in the mineralizing fluids is supplied by digestion of these xenolites. in postmagmatic mineralization, thorium migrates in alkaline solutions, particularly in the form of complex carbonate compounds with the formula th(co3)n –(2n–4) (titayeva, 1994). according to the presence of paragenetic calcite accompanied with thorite and sphene in th-ree mineralization, th and ree transport was likely because of the presence of the carbonate complexes in mineralizing fluids. according to titayeva (1994) and pirajno (2009) at the end of albitization processes, the thorium and uranium concentrations increase. part of ree and u-th is retained in microfissures filled with haematite and chlorite. the reddish colour is attributed to the presence of micro-haematite in micro-fractures. although, wilde (2013) has portrayed that the red or pink coloration is owing to the presence of fine-grained disseminated haematite or hydrothermal apatite. our data revealed that albites from the choghart th-ree mineralization zone contain k-feldspar and minor th silicate mineral inclusions (i.e. thorite) that give albite a more reddish colour (figure 4b). 6. conclusions moore & modabberi (2003) suggest that the separation of an iron oxide melt and the following hydrothermal processes dominated by alkali metasomatism have both been involved to in different degrees in the formation of the choghart deposit. alternatively, the choghart rhyolite is enriched in th and lree similar to other continental margin felsic volcanic rocks. chondritenormalized ree patterns of the choghart rhyolite are similar to the th-ree mineralization zone, indicating that th and ree originated from a continental margin choghart rhyolitic magma. we suggest that in the early cambrian (about 533 ma) calcalkaline granitoid magmatism associated with a subduction zone in the choghart deposit initially formed a magnetite-apatite ore body and sodic-calcic alteration followed by penetration of the remaining magmatic fluids into the rhyolitic host rocks and also sodic-calcic alteration related to iron mineralization and partially brecciation. these fluids maintain elevated concentrations of metals such as fe, th and ree that were originally scavenged from the rhyolitic silicate melt due to the magmatic temperatures and high salinity of the fluid (reed et al., 2000; simon et al., 2004, 2005, 2006; zajacz et al., 2012; frank et al., 2011; migdisov et al., 2014; hurting & williams-jones, 2014). these fluids caused sodic metasomatism (albitization), carbonatization, actinolitization and pyroxenitization, minor k-feldg eo lo gi a c ro at ic a geologia croatica 70/168 spatization (microcline) as well as generation of the minerals such as thorite and sphene. alternatively, the th-ree mineralization zone may have formed from entirely different fluids related to a later intrusion such as the resurgent central plutons. the high co2 content of the fluid facilitates formation of metal-carbonate complexes. the presence of paragenetic calcite with thorite suggests that carbonate complexes most likely transferred the th and ree. considering that dolomitic xenoliths of the esfordi formation are observed in the volcanic host rocks of the choghart deposit, the portion of co2 in the mineralizing fluids is supplied by digestion of these xenoliths. the negative eu anomaly from the th-ree mineralization zone and the presence of paragenetic magnetite, pyrite and chalcopyrite with thorite suggests relatively reduced conditions in the th-ree mineralization environment. acknowledgement this paper is based partly on the main author’s phd thesis at shahid beheshti university of tehran, iran. this research was also supported by the nuclear science and technology research institute of aeoi and shahid beheshti university research centre. references aghanabati, a. (1998): major sedimentary and structural units of iran (map).− int. geosci., 7, 29–30. aghanabati, a. (2008): stratigraphy encyclopedia of iran – precambrian to silurian.– geological survey survey and mineral exploration of iran. tehran, 658 p. alavi, m. (1991): tectonic map of the middle east (scale 1:5.000.000).– geological survey and mineral exploration of iran, tehran. bagheri, s. & stampfli, g.m. (2008): the anarak, jandaq and posht-e-badam metamorphic complexes in central iran: new geological data, relationships and tectonic implications.– tectp., 451, 123–155. doi: 10.1016/j.tecto.2007.11.047 bau, m. & möller, p. (1992): rare earth element fractionation in metamorphoge nic hydrothermal calcite, magnesite and siderite.– mineral. and petrol., 45, 231–246. doi: 10.1007/bf01163114 cuney, m., emetz, a., mercadier, j. & mykchaylov, v. (2012): uranium deposits associated with na-metasomatism from central ukraine: a review of some of the major deposits and genetic constraints.– ore geol. rev., 44, 82–106. doi: 10.1016/j.oregeorev.2011.09.007 dahlkamp, f.j. (1993): uranium ore deposits.– springer-verlag, berlin, 460 p. doi: 10.1007/978-3-662-02892-6 dahlkamp, f.j. (2009): uranium deposits of the world – asia.– springer-verlag, berlin, 493 p. daliran, f. (2002): kiruna-type iron oxide-apatite ores and ‘apatites’ of the bafq district, iran, with an emphasis on the ree geochemistry of their apatites.– in: porter, t. m. (ed.): hydrothermal iron oxide copper gold and related deposits: a global perspective., 2. pgc publishing, adelaide, australia, 303–320. daliran, f., stosch h.g. & williams, p.a. (2009): review of the early cambrian magmatic and metasomatic events and their bearing on the genesis of the fe oxide-ree-apatite deposits (ioa) of the bafq district, iran.– in: williams et al. (eds.): smart science for exploration and mining, proceedings of the 10th biennial sga meeting, townsville, australia 17th–20th august. dehghan, a.r. (2011): geological prospecting plan of the choghart deposit, 1:4200, report of central iron ore company (in persian). feldman, g.k. (1926): about some varieties of spherulite quartz of the zhovtarichka mine.– dnipropetrovsk: bull. geol. mining circle of dnipropetrovsk mining institute, 2. forster, h. & jafarzadeh, a. (1994): the bafq mining district in central iran a highly mineralized infracambrian volcanic field.– econ. geol., 89, 1697–1721. doi: 10.2113/gsecongeo.89.8.1697 frank, m.r., simon, a., pettke, t., candela, p. & piccoli, p. (2011): gold and copper partitioning in magmatic-hydrothermal systems at 800°c and 100 mpa.– geochim. cosmochim acta, 75/9, 2470–2482. haghipour, a. (1977): geological map of the biabanak-bafq area.– geological survey of iran, scale 1:500.000. haghipour, a. & pelissier, g. (1968): geology of the posht-e-badam-saghand area (east central iran).– iran geological survey note, 48, 144 p. huckriede, r., kursten, m. & venzlaff, h. (1962): the geology of the area between kerman and saghand (iran). beih.– geol. jb., 53, 197 p. hurting, n.c. & williams-jones, a.e. (2014): an experimental study of the transport of gold through hydration of aucl in aqueous vapour and vapour-like fluids.– geochim. cosmochim. acta, 127, 305–325. iaea (2014): uranium 2014.– resources, production and demand, 504 p. kargaranbafghi, f., neubauer, f., genser, j., faghih, a. & kusky, t. (2012): mesozoic to eocene ductile deformation of western central iran: from cimmerian.– tectp., 564–565, 83–100. kinnaird, j.a.(1985): hydrothermal alteration and mineralization of the alkaline anorogenic ring complexes of nigeria.– african earth sci., 3, 229–252. doi: 10.1016/0899-5362(85)90038-7 leake, b.e., wooley, a.r., arps c.e.s., birch, w.d., gilbert, m.c., grice, j.d., hawthorne, f.c., kato, a., kisch, h.j., krivovichev, v.g., linthout, k., laird, j., mandarino, j.a., maresch w.v., nickel, e.h., rock, n. m.s., schumacher, j.c., smith, d.c., stephenson, n.c.n., ungaretti, l., whittaker, e.j.w. & youzhi, g. (1997). nomenclature of amphiboles: report of the subcommittee on amphiboles of the international mineralogical association, commission on new minerals and mineral names.– am. mineral., 82, 1019–1037. migdisov, a.a., bychkov, a.y., williams-jones, a.e. & van-hinsberg, v.j. (2014): a predictive model for the transport of copper by hcl-bearing water vapour in ore-forming magmatic-hydrothermal systems: implications for copper porphyry ore formation.– geochim. cosmochim. acta, 129, 33–53. doi: 10.1016/j. gca.2013.12.024 mirzaei beni, z., emami, m.h., sheikhzakariaee, s.j. & nasr esfahani, a. (2014): petrography of plutonic rocks in the late cambrian (rizu series), sechahun iron oxide deposit, bafq mining district, central iran.– biodiversity and environmental sciences (jbes), 5/4, 610–616. mohammad torab, f. (2008): geochemistry and metallogeny of magnettite-apatite deposits of the bafq mining district, central iran.– ph.d thesis, faculty of energy and economic sciences, technical university of claustal, 131 p. moore, f. & modabberi, s. (2003): origin of choghart iron oxide deposit, bafq mining district, central iran: new isotopic and geochemical evidence.– journal of sciences islamic republic of iran, 14/3, 259–270. morimoto, n., fabries, j., ferguson, a.k., ginzburg, i.v., ross, m., seifert, f.a. & zussman, j. (1988): nomenclature of pyroxenes.– am. mineral., 73, 1123–1133. nadimi, a. (2007): evolution of the central iranian basement.– int. gondwana res., 12, 324–333. doi: 10.1016/j.gr.2006.10.012 pirajno, f. (2009): hydrothermal processes and mineral systems.– springer, 1250 p. doi: 10.1007/978-1-4020-8613-7 pirajno, f. (2013): effects of metasomatism on mineral systems and their host rocks: alkali metasomatism, skarns, greisens, tourmalinites, rodingites, black-wall alteration and listvenites.– in: harlov, de. & austrheim, h. (eds.): metasomatism and metamorphism: the role of fluids in crustal and upper mantle processes. lecture series in earth science, springer, 203–251. doi: 10.1007/978-3-64228394-9_7 pollard, pj. (1983): magmatic and post-magmatic processes in the formation of rocks associated with rare element deposits.– trans. inst. min. metall., 92, b1–b9. rajabi, a. (2008): geology, mineralogy, texture and structure, geochemistry and genesis of chahmir zn-pb deposit, south of behabad, yazd province.– m.sc. thesis, faculty of science, tarbiat modares university, iran. rajabi, a. (2012): ore controlling parameters and genesis of sedimentary exhalative zn-pb (sedex type) deposits, zarigan-chahmir area, east of bafq, central iran.– ph.d. thesis, faculty of science, tarbiat modares university, iran. rajabi, a., rastad, e., alfonso, p. & canet, c. (2012): geology, ore facies and sulfur isotopes of the koushk vent-proximal sedimentary-exhalative deposit, posht-e-badam block, central iran.– int. geol. rev., 54, 1635–1648. rajabi, a., canet, c., rastad, e. & alfonso, p. (2015): basin evolution and stratigraphic correlation of sedimentary-exhalative zn-pb deposits of the early cambrian zarigan-chahmir basin, central iran.– int. ore geol. rev., 64, 328–353. ramezani, j. & tucker, r. (2003): the saghand region, central iran: u-pb geochronology, petrogenesis and implications for gondwana tectonics.– american j. sci., 303/3, 622–665. doi: 10.2475/ajs.303.7.622 reed, m.j., candela, p.a. & piccoli, p.m. (2000): the distribution of rare earth elements between monzogranitic melt and the aqueous volatile phase in experimental investigations at 800°c and 200 mpa.– contrib. mineral. petrol., 140, 251–262. samani, b. (1993): saghand formation, a riftogenic unit of upper precambrian in central iran.– int. geosci., 6, 32–45. saunders, a.d., & tarnery, j. (1991): back-arc basins.– in: floyd, p.a. (ed.): oceanic basalts. blackie, glasgow, 219–263. doi: 10.1007/978-1-4615-3540-9_10 schandl, e.s., & gorton, m.p. (2002): appplication of high field strength elements to discriminate tectonic setting in vms environments.– econ. geol., 97, 629–642. simon, a.c., pettke, t., candela, p.a., piccoli, p.m. & heinrich, c.a. (2004): magnetite solubility and iron transport in magmatic-hydrothermal envig eologia c roatica 69khoshnoodi et al.: alkali metasomatism and th-ree mineralization in the choghart deposit, bafq district, central iran ronments.– geochim. cosmochim. acta, 68, 4905–4914. doi: 10.1016/j. gca.2004.05.033 simon, a.c., pettke, t., candela, p.a., piccoli, p.m. & heinrich, c.a. (2005): gold partitioning in melt vapor-brine systems.– geochim. cosmochim. acta, 69, 3321–3335. doi: 10.1016/j.gca.2005.01.028 simon, a.c., pettke, t., candela, p.a., piccoli, p.m. & heinrich, c.a. (2006): copper partitioning in melt-vapor-brine-magnetite-pyrrhotite assemblage.– geochim. cosmochim. acta, 70, 5583–5600. doi: 10.1016/j.gca.2006.08.045 smith, r.e. & smith, s.e. (1976): comments on the use of ti, zr, y, sr, k, p and na inclassification of basaltic magmas.– earth and plan. sci. lett., 32, 114–120. stampfli, g.m. (2009): terranes map of the western tethysides.– unil, university of lausanne (open file). stosch, h.g., romer, r.i., daliran, f. & rhede, d. (2011): uranium-lead ages of apatite from iron oxide ores of the bafq district, east-central iran.– mineral. deposita, 46, 9–21. doi: 10.1007/s00126-010-0309-4 sun, s.s. & mc donough, w.f. (1989): chemical and isotopic systematics of oceanic basalts; implications for mantle composition and processes.– in: saunders, a.d. & norry, m.j. (eds.): magmatism in the ocean basins. london, uk, geological society of london, 313–345. doi: 10.1144/gsl.sp.1989.042.01.19 taghipour, s., kananian, a. & somarin, a.k.(2013): mineral chemistry and alteration parageneses of the choghart iron oxideapatite occurrence, bafq district, central iran.– neues jahrbuch für geologie und paläontologie, 269/3, 221–240. tanatar, i.i. (1925): new rocks of the kryvy rig iron ore basin: part1.– injenerny rabotnik, 7. titayeva, n.a. (1994): nuclear geochemistry.– crc press, 304 p. wilde, a. (2013): towards a model for albitite-type uranium.– j. minerals, 3, 36–48. doi: 10.3390/min3010036 winchester, j.a. & floyd, p.a. (1977): geochemical discrimination of different magma series and their differentiation products using immobile elements.– chem. geol., 20, 325–343. doi: 10.1016/0009-2541(77)90057-2 wood, d.a. (1980): the application of a th-hf-ta diagram to problems of tectonomagmatic classification and to establishing the nature of crustal contamination of basaltic lavas of the british tertiary volcanic province.– earth planet. sci. lett., 50, 11–30. wood, s.a. (1990a): the aqueous geochemistry of rare earth elements and yttrium. 1. review of available low-temperature data for inorganic complexes and the inorganic speciation of natural waters.– chem. geol., 82, 159–181. wood, s.a. (1990b): the aqueous geochemistry of rare earth elements and yttrium. 2. theoretical predictions of speciation in hydrothermal solutions to 350°c at saturation water vapor pressure.– chem. geol., 88, 99–125. yaghubpur, a. & mehrabi, b. (1997): koushk zinc-lead deposit a typical blackshale-hosted deposit in yazd state, iran.– j. sci., i.r. iran, 8/2, 117–125. zajacz, z., candela, p.a., piccoli, p.m., walle, m. & sanchez-valle, c. (2012): gold and copper in volatile saturated mafic to intermediate magmas: solubilities, partitioning, and implications for ore deposit formation.– geochim. cosmochim. acta, 91, 140–159. doi: 10.1016/j.gca.2012.05.033 zhou, j.x. (1999): geochemistry and petrogenesis of igneous rocks containing amphibole and mica: a case study of plate collision involving scotland and himalayas.– science press, new york and beijing, 41–72 geol. c roat. 49/1 81 115 4 figs. 5 pis. zagreb 1996 the conodonts hindeodus, isarcicella and sweetohindeodus in the uppemlost permian and lowermost triassic heinz kozur key words: conodonts, hindeodus, isarcicella . s'l-veel ­ ohilldeodu5, p{ f boundmy. abstract liilldcodus rexroad & furn ish , 1964 and isarcice lfa kozu r, 1975 belong to the strati graphically most important fossi ls nc<l r the permian -tri ass ic boundary. the first appearance of ii. pan' li.\" (k oz ur & pj at a kova) in the phylomorphogcncl ic l in­ eage ii. fjpica/is h. /a(idelllalm pmeparl'lfs h. pan'us is the best marker for the p(t boundary. some representati ves o f 1i;iic/co(/iis and i.wrcicella arc insuffi cientl y known. consequently, all known liill­ deodll.\" and ! safeicella spec ies fro m near the prr bo undary, lirc rcdcscribcd or di sc ll s.~c d. flill deodus (janus erec/ii s n.subsp. , 1-1. j ltlfe ll sis wardlowi n.subsp., ii . fa /idell/a/iis praepal"l'i/s n. subsp. and ii . sosioellsis tl .sp., and lhe new gen us sli'ec/ohindf'odl/s n.gen. with two species, swcetohindeodll.\· hidel1l(1/us il.gell. n.s)) . and s. iridel1la · 111.1' life proposed. i. introduction strong provinc ialism during the permian mnkes the correlation of the boreal and notal faunas with those of the tropical te thyan realm difficult . this provincialism continued th roug h the uppe rmost pe rm ian changxi n­ ginn stage and the very base of the triassic (i./. parvlis zone), whe re the trop ical faunas of the centra l te thys and the boreal and notal oroeeras fauna s are very dif~ ['eren!. almost all foss il groups arc strongly influenced by the pe rmian provinc iali sm. th e ammonoids a re ve ry di ffe rent and fu sulinids are even unknown in the boreal realm above the road ian. a lso te thyan brach iopods are rathe r diffe re nt from boreal and nota l re presenta­ tives that show often a bipolar distribution. conodonts are only s li ghtly affected by the perm ian provincialism . for instance, vja{ovognathlls kozur is res tricted to the temperate and cool water or the margin of eas tern gondwana and the peri ~gondwana te thys. ribbed species of mesogolldolella kozur a rc res tri ­ c ted 10 shallow pe lag ic warm water de posits, and a rc the re ro re mi ss in g in the co ld pal acopsyc hrospheric e nvironm e nts (koz ur , 1991a, b) of the pe rmian ocea lls and deep wat e r deposits of open sea ma rgi ns. clarkincl kozur also shows distinct provinc iali sm. c. rezsii u. 83. h-1029 budapcsl, l lungary. rosellkrallizi (ben der & stoppel) is res tric ted to e ithe r tempe rate or coo l wale r areas o f the arc tic and the per i ~gondwana tethyan margin. other species, such as c. c/wngxillgellsis (wang & wang), occ ur both in the arctic (e .g. in the lowe r 0, boreale zone of seto­ rym ri ve r in ne siberia) and in the tropical te thys (from s ic il y to south c hina). othe r c!m'king spec ies (see sec tion 3) pre fer the tropical realm or arc res tric ted to this area. wit h the es tab lis hme nt of a mo nd iall y rather un ifolti1 fauna a little above the base of the trias­ sic, advanced re presentatives of the c. carina/a g roup are also present globally since the i. isarciea zone. i-lindeodlls rexroad & furnish shows no provin c iali sm , occurs across the p(f boundary and unde rwe nt rapid morphologi cal changes within the changx ingian and lowermos t triass ic . thi s genu s is the refore bes t suited [or de fi n ing the prr bo undary with in a phylomorphogenetic l ineage. the developme nt from if. {arie/cflfaflls praepar l' lis n. subsp. to h. pa/'\'li s kozur & i'jatakova can be observed in continu­ ous sec tions wi th temperate to cool water faunas of the boreal realm (green land) and at the peri-gondwana margin of the te thys (kashmir, salt range) , as well as in cont inuolls sections in lhe tropical realm (e.g, south~ ern alps, hungary, sicil y. ce ntral tran , t ranscaucas ia, south c hina). the first appearance of i-i. pm'vlts within th is phylomorphogenetie lineage is therefore or extra­ ordinary importance for definition oj" the prr boundary. thi s event occ urs, for instance, in the middle part oj" boundary b ed 2 at mei shan (south china), so fa r regarded by the present au thor as the most suitable can ~ cl iclate o f the global s tratotype section and point (gss p) for the base of the triassic (fi gs . 1,2). however, in a country, like china, an offic ial state guaranted pe rm a­ nent access to meishan for all sc ienti s ts is necessa ry , before mei shan can be regarded as an official candidate for this gssp. this includes a lso free sample tran sport out 01" china without custom barriers and special expen­ s ive allowiless in the fram e o f coope ration of ch inese scie nti s ts with fo re ign ins ti tuti ons because free access mcans not only the possibi lity and allowness for every­ body to vi s it a gssp in a kind of "geotourism", but al so to sludy it. in the present pape r the taxonomic s tatus oj" the upper permian and lower triass ic hille/eoe/us and i sar­ d eella species is considered , because the separat ion of some s pccies was not we ll known in the past. three 82 "" '" '" ~ _______ +~m~e~;s~h~a~n_'~~~~?l~ __ +r~~ __ ~\-t1" changx ing ~~.----+-=~=4---~~ " 30 60 'm fi g. 1 geographical sc1!ing of the mcishan section. star represent s locution of the m eishan section in south cjlina. new hille/eodus species/subspecies and the new genus swectohindeoc/us with two new species are proposed. moreover, the importance of the first appearance of h. parvlls lor the definition of the prr boundary and relat­ ed problems of the facies control for the distribution of i-lindeodffs and gondolellids near the prr boundary are discussed. 2. the import ance of the first appearance of hindeodlts parvlts for the definition of the base of the triassic ii. parvl/s is easi ly determinable and readily scpara­ ble from its forerunner h. lafidentafus praeparvlis (sec systematic pari), and its derivation is well documented by transitional forms. in several sections (as mentioned above) both taxa occur in a stratigraphic sequence con­ nected by transitional forms. /-!. parvlfs has a far wider distribution than any other conodon t or ammonoid species ncar thc prr boundary, because it occurs both in ammonoid-free, shall ow waler, high energy werfell facies and in pelagic facies with or without ammonoids. it is known so far from the southern alps, dinarides, hungary, sicily, crete, tran­ scaucasia (with the type locality), nonhwestern and central iran, elburz, kashmir, salt range, himalaya, china, japan, greenland, arclic canada and western north america. this distribut ion covers the entire trop­ ical t ethys, circum-pacific realm, cratona l north america, cold/cool water boreal realm and the coo l watcr to temperate peri-gondwana margin of the tethys. i-i. parvl/s therefore has no zoogeographic restriction. geologiil croi1tici1 49/1 h. parvus is the first globally distributed species to appear after the minimum in faunal divcrsity indicated by the minimum in 813c. at meishan, it appears 5 cm above that minimum. the first appearance of h. pm'vlls coincides with or slightly pos tdales the disappearance of upper changxin­ gian (uppermost perm ian) gondolell ids (tlan, 1993, 1994; kozur, 1994a, b, 1995a, b), such as c. dej/eela (w ang & wang), c. diceraearillala (wang & wang) , c. postwallgi (tian), c. sasiaellsis gullo & kozur, c. suhcarinala (sweet) and clarkilla xiallgxicnsis (tian), and of upper permian hilldcodus, such as h jul/ellsis (sweet) and h lalidelllaills lali­ delllaills (kozur, mostler & rahimi-yazd). it also coincides wit h the disappearance of slepallovilcs kozur and slightly postdates the appearance or ellisonia muller s.str., whereas c. cliangxingensis (w ang & wang) and h. lalidelliatus praeparvl/s disappear in the lowermost part of the f-l. parvl/s zone. permian iype ammonoids, such as hypophiceras, plelf ­ ronodoceras, pseudogaslrioceras and psclfdoliroliles, and albaillellacean radiolarians disappeared immediate­ ly before the first appearance of h. parvl/s. ophiceras appeared nearly con temporaneollsly with h. panjlfs. the globally distributed marine fungus tympanicysta sloschiana (balme) (pi. y, figs. 10, ii) di sappeared close to the first appearance of l-i. parvus. the sim ilarly widely distributed lsarcicella isarcica slaeschci dai & zhang and claraia wangi (patte) appeared slightly above the first appearance of h. parvus. thus , there are many biostratigraphic markers at or near to the base or the h. parvlis zone. in al l sections where the carbon isotope ratios have been investigated ncar the pit boundary, the first appearance of il. parvlfs lies a little above the minimum in 8 1l c. in sections where a lithostratigraphic event boundary is prese nt , h. pm·vlis appears a little above that boundary (c.g. in mcishan l5 clll above the eventstratigraph ic boundary). moreover, ncar the base of the h. parvlfs zone a widespread anoxic event began. the prr boundary defined with the first appear­ ance of h. parvus is therefore also very close to a "nat­ ural boundary" sensu newell (1994). the first appearance of h. parvl/s is close to the tra­ ditional pit boundary at the top of the changxingian. in south china, this boundary was placed either some­ what above or below the ri rst appearance of h. parvlfs. until the monograph of zhao et a1. (1978), it was placed at the base of the claraia wangi zone, which in the meishan sections is 12 em above the first appear­ ance of h. parvl/s. kozur (1977a, 1989) defined the pit boundary with the first appearance of isarcicella isarcica, thai is 8 cm above the first appearance of h. parvl/s. subsequently, zhao et a1. (1981) placed this boundary at the base of boundmy bcd 1 (= base of the transitional beds) that is [5 em below the first appear­ ance of h. parvl/s. still later, the lower part of bound ­ ary bed i ("wh it e clay") was again included in the permian (because of its permian conodont fauna) and kowr: tile conodonts hil/deodus, imrcicella and sweetohilldeodus ... 83 conodont stage zone subzone formation lithostratigraphy and fauna bed 29 (26 em) gray, medium bedded, silty, dolomitic marls ophiceratids; bivalve: claraia wangi; brachiopod: paryphella orbicularis; isarcicella conodonts: clarkina carinata, ellisonia transita, isarcicella isarcica, isarcica i. ? turgida t grayish yellow illite~montmorillonite clay. r bed 28 (4 em) i conodonts: hindeodus parvus, isarcicella isarcica staeschei, i. ? turgida a brahmanian bed 27 (16 em) light gray, silty limestone. s ("induan") s brachiopods: crurithyris flabefliformis, fusichonetes pigmaea, paracrurithyris i pigmaea, paryphella orbicularis, p. triquetra, waagenites barusiensis; c hindeodus the following detailed conodont distribution was found in bed 27: parvus 12-16 em: clarkina carinata, c. changxingensis, ellisonia transita, hindeodus parvus, h. typicafis 8·12 em: clarkina carinata, c. changxingensis, ellisonia transita, hindeodus changxingensis, h. latidentatus, h. parvus (on ly primitive forms, transitional to h. latidentatus), h. typicalis, isarcicella? prisca lower qinglong 4-8 cm: clarkina carinata, c. deflecta, hindeodus typicalis, isarcicella? or prisca, merrillina longidentata, stepanovites sp. yingkeng 0·4 cm: cfarkina carinata, c. changxingensis, c. procerocarinata, ellisonia formation transita, hindeodus changxingensis, h. latidentatus, h. typicalis, fsarcicella ? prisca bed 26 (6 em) "black clay" (dark·gray montmorillonite-illite clay, partly calcareous and silty) . ammonoids: hypophiceras changxingense, h. cf . martini, otoceras? sp., metophiceras sp., pseudogastriocerassp.; bivalve: peribositra baoqingensis; brachiopods: araxathyris min uta, cathaysia chonetoides, crurithyris flabelfiformis, neochonetes convexa, neoweflerella pseudoutah, paracrurithyris pigmaea, parypheffa orbicularis, p. sulcatifera, p. triquetra, waagenites barusiensis, w. wongiana; conodonts: clarkina cf. carinata, c. changxingensis, c. dicerocarinata, c. deflecta, c. meishanensis, c. ct. sosioensis, c. xiangxiensis, hindeodus latidentatus clarkina p xiangxiensis bed 25 (4 em) "white clay" (light bluish gray, weathered yellowish white e clarkina illite·montmorillonite clay). r deflecta conodonts: clarkina ct. carinata, c. changxingensis, c. deflecta, c. ct. m changxingian meishanensis, c. xiangxiensis, hindeodus latidentatus; non-fusulinid i hindeodus foraminifer s: bradyina sp. , globivalvulina sp., hemigordius sp. a latidentatus n bed 24 e (20 em) dark gray bedded micrite. ammonoids : rotodiscoceras sp.; brachiopods: crurithyris flabelliformis, neoweflereffa pseudoutah, weffereffa delicatufa; conodonts: clarkina d. carinata, c. changxingensis, c. deflecta; fusulinids: palaeofusulina sp. bed 24 d (23 em) dark gray, bedded wackestone with very thin bioclastbearing calcareous mudstone interbeds. upper ammonoids: pleuronodoceras mirificus, pseudogastrioceras sp.; conodonts: changxing formation clarkina ct. carinata, c. changxingensis, c. deflecta, c. xiangxiensis, hindeodus (meishan latidentatus; foraminifers: palaeofusulina ct. sinensis, geinitzina caucasica, member) nodosaria netchajevi, pachyphloia lanceo/ata beds 24 e and b (28 em) dark gray, bedded dolomitic packstone with thin clay interbeds. clarkina postwangi conodonts: clarkina changxingensis, c. deflecta, c. postwangi bed 24 a (idem) dark gray, bedded wackestone, thin clay bed at the top. conodonts: clarkina cf. carinata, c. changxingensis fig. 2 lithology, fa unal di stribution and conodont zonation around the penn ian-triassic bou ndary in the meishan section, south china. beds 25 and 26 correspond to the lower trans itional beds by yin (1985) and to the boundary bcd 1 by wang (1994). bed 27 corresponds to the upper transitional beds and to the boundary bed 2. conodont distribution after kozur el al. (1996) and wang et a1. (1996). ,. .he p{f boundary was placed at the base of the "b lack clay" (upper part of boundary bcd i), ii em below the first appearance of ii. parl'lis (yin et ai., 1988; yang et ai., 1993). yin ([993) and yin et al. (1994) placed the p(f boundary at the base of boundary bcd 2, which lies 8 em below the first appearance or h. porvl/s, but defined the r(f boundary with lhe base or the 1-1 . parvl/s zone. kozur ([ 994b, 1995a, b) and wang (1994, 1995a, b) placed the base of the triassic at the base of the h. p0i"i'iis zone at a level 8 elll above the base of boundary bed 2 (middle part of bcd 27). on the peri-gondwana ma rgin of the tethys h. parvlls appears within the o. lori/oballllll bed at sclong. o. /oliloballlm 'vvang & he is a junior synonym of o. /issisellallllll d[ener (krysty n, in krystyn & orci-iard, 1996) and represents in the peri-gond­ wana oroceras faunas the arctic uppermost o. boreafe zone or the level with the first vciy primitive h. par viis in greenland, above the last o. borea/e and below rich occurrences of c/araia stachei l3 tttner of the lower ophiceras coli/liiulle zone. the data presented by krystyn (in kr ystyn & orci-iard, 1996) con­ firm the conodont eorre[ations by kozur ([994b) that the peri-gondwana o. woodwordi zone is younger than the aretie owceras faunas and represen ts the lower part of the arctic o. col/lfllulie zonc. as the otoceras beds of thc sc long section are s trongly condensed, the first primitive h. pan'lis from the upper o. "/atilobo ­ tllm" bed may represent al ready the basal oroceras woodwardi oplticeras balldoi zone. the entire laller zone contains h. pan'ffs nearly in all sections. only in kashmir, h. pan'ffs appears within the o. woodwardi zone, seemingly ncar to the first appearance of oph­ items (matsuda, [981). this may be explained eit he r by insurrieiant conodont data from the lowennost bed of the ofoceras fauna because the follow ing bed con tains already advanced speci mens or ii . pan'lis, or the oloceras from the lowe rmost bed or the oloceras fauna belongs to the o. borea/e group (suture zone not yet re-studied nceording to the criteria e laborated by krystyn in krystyn & orcliard, [996). as the base o r the triassic was defi ned with the base of the o. woodwartli zone in central himalaya, the base of thc h. parl'lis zonc is ve ry close to or coin­ cides w ith the traditiona l base of the triassie . it is, however, cons ide rabl y younger than the base of (he o. col/cavum zone that is used to define the base of the triassic in the arctic. yin ([985,1993), kozur (l994a, b, 1995a, b), pau ll & paull ( [994), yin e t al. ( [994), wang ([ 994, 1995a, b), kozur et al. ([ 996), wang et al. ( 1996), wignall e t al. (1996) and jln e t al. ( 1996) used the base of the ii . parl'iis zone as base of the tri­ assic. ro[[owing yang e t al. (1987), yin et al. (1994) proposed section d at meishan (south china), the stra­ totype of the changxingian stage, as assp of the prr boundary. wang ( 1994,1995", b) proposed the quar­ ry z (zhongxin dadui section) of the meishan section as gssp, following s heng et al. (1984). wang et al. gcoiogl;l cro;l!ica 49/1 (1996) left open the decision to use secti o n d or the zhongxin dadui section, about o.s km east of section d as gssp for the pit boundary. kozur et al. ([ 996) regarded meishan as a laterally continuous section as proposed by yin in a report about the activities or the p{f boundary working group. this view is also adopt­ ed in the present paper. the meishan section eons ists of 7 quarries on the southern s lope of the meishan hill (changxi ng county, zejiang province, south china, fig. i) separated by distances of 70 400 m. they arc named as quarry a, b, c, 0 (baoqing quarry, stra totype of the changxin­ gian stage), e, f and z (zhongxi n dadui quarry). the beds of these quarries have identical thicknesses, facies and fossil content (fig. 2) and as they are laterally traceable, they have been numbered around the prr boundary in all quarries in the same manner. the per­ mian-triassic boundary l3eds (transitional l3eds) and lowermost triassic rocks are exposed in all of these quarries, while the exposed part of the changxing limestone and of the lower triassic beds is d ifferent. quarry d exposes the e ntire changxi ngian and the low­ e rmost triass ic, the other quarries only the middle and upper part of the changxing limestone, the l30undary beds and different parts of th e lower scythian. best studied are quarries 0 and z and the gssp sho uld be fix ed in one of these two quarries by the chinese col­ leagues (sec, however, remarks to the general accessi­ bi lity of chinese sections in section 1). the large lateral extent of the meishan secti on allows the collection of very large samples and also the possibil it y of finding very rare fossils, such as ammonoids. wang (1994) useel tile first appearan ce of h. parvils 1110rphotypc [ sensu kozur ([ 990a) for de fini ­ tion of the prr boundary. this form is easily recognis­ able. offen even in broken spec imens. ho weve r, both morphotypes firs t appeared ai the same level. accord ­ ing to wang (pel's. comm.) both morphotypes have a s li ghtly different range. t o avoid nomcnclatoral prob­ lems, illorphotype i is herein described as a new su b­ spee ies h . parvlis ace/lis n.subsp. followin g wang ([ 994), the p{f boundary can be elci'ineci by the firs t appearance or h. porvfls erecfl/s. within l3ed 27 (boundary bed 2, upper transitional beds). 3. the impact of biofacies on the distribution of hilldeodlls and "on­ dolellids near the pit boundary according to orci-[ard (in krystyn & or­ chard, [996) and orchard (1996), gondo [el [ids (neogolldolella s .1. sens u orchard) are 1110re eoi11mon in offshore, deeper, and/or coole r wate r marine env ironme nts, whereas liilldeod/ls flouri shed in near­ shore, sha llowe r and/or wanner regions. th e faci es control of gondole llids with respect to the water depth is well known since more than 40 years, whereas the tempe rature control was only s tudied in the last years k07i1r: '!lie conodont~ ihll(!('odus. /sarcicrlla and sw('l'/ohim!nh!uf .. , (kozu r, 1995a). o rchard 's remarks in respeello ihe facies control or gondole llids arc in general agreement with ronner published data , except for the temperature control. there are go nd ole llids, restri cted to warm water pe lagic ellvironmen ts, e.g. all ribbed middle per­ mian mesogolldolel/a, such as m. l1allkillgensis (chi ng) or m. pos/serrara (beh nken), and gondo­ le llids that are res tric ted to cold water of high la titudes and co ld bottom -water of low latitud es, such as m, pl/osphoriellsis (yo ung quist, hawley & mil­ ler) and m. siei/iellsis (koz ur). thi s lemperalure control of mesogolldolella has lead often to stra tigraph­ ic mi sinterpretations espec iall y in areas wit h cold bol­ tom-water fauna s and periodical input or shallow ­ pelagic warm water faunas_ as mentio ned above, clarkina shows the same facies dependence. most upper pcrmian spec ies, such as c. ori el/ talis (bar­ skov & korolev a), c. slibearillara (s weet) , c. lel'(,lii (kozur, mostler & pjatakov a), c. diccrocarill ara (wang & wang) prefcrrcd warm wate r pe lag ic environment s or are res tri c ted to such fac ies. in the cont rast, c. c l carinaw (clark ) is res tri cted to upper pe rmian cold/cool wate r fau nas, such as the boreal lower otoeeras faunas and the con­ odont faunas of the undi sputed upper permian upper­ most ch hidru formation (sa lt ran ge), immediately below th e likewi se undi sput ed uppcr permian whitc sandstonc member. my study of the mate rial publishcd by sw eet ( 1970b) has shown ihal he was correcl in de termination or clarkillo or the c. carilla(a gro up in ihese deposils. according 10 orchard ( 1996) sueh faunas have a triassic character. the c. ear illma group (with advanced represent atives) had adapted to warm water no earlier than in the i. isareica zonc. for thi s rcjson , the h. pa/"\'li s zone of the central and wcstern tropica l tcthys h,as no gondolellids afte r the disappear­ ance of the permian warm water species and be fore the appearance of warm water adapted advanced clarkina carinata in the i. isarcica zone. this is especially inter­ es tin g in continuous pe lagic sequcnces, as in western s ic ily , where pelag ic graded limestones of both the entire changxingian and the lower triassic i . isareiea zone y ielded very ri ch clarkina fauna s (mostly with very few i-lilldeodf(s), whereas in graded calcarenites of the 1-1. parl 'f(s zone (deposi ted under the same or a little large r wate r depth ) no sin gle clarkil10 was found in a co nodont fauna cons isting exc lusively of h . parvlis (this illonospecifie fauna is rich in specimens). no such tempera ture control fo r the distribution oj" triass ic neogolldolella bender & stoppel and paragolldo­ lelia mosher can be observed. bul ihese gondole ll ids be long to an other stock than the permian m esogondo­ lelia and the permian to lowermost t ri assie clarkina, and have evol ved rrom the plalrormless neo,\"palhodlfs mosher through chejlgylfallia kozur (for pm-ago­ iido/c//a, within the lowermost olcnekian) and through citiose lla kozur (for neogolldolella , wilhin ihe low­ ermost anis ian). the ancestral neosp(f/hodlf:f al so shows no obv ious temperat ure dependence. there is no gondolellid preference for orfshore deposil s as indiealed by orchard ( j996). the fre­ quency of gondolellids has its maximum in nearshore deeper water (if such deposits are present) and decreas­ es significantly in offshore deeper water. however, thi s is ra ther re lated to the nutri ent supply than to the di s­ tance from the shore line. because nearshore limy sedi ­ ment s arc ra re compared with offshore pelagic lime­ stones, thi s rel ations can be observed only in few pjaees. the upper permian and lowermost triassi c hille/eo­ dus spec ies al so have different faci es control for difter­ enl species. h. jll/fellsis (sweet), h. imidelllallls lati­ del/lalls (kozur, mostler & rahimi-y azd), h. ehangxillgen.\-i.\wang and h . olfudael1sis kozur & mostler are restric ted to deeper, but warm wate r environments. thcy arc never found in contemporane­ ous shallow water faci es but arc also missing in deep water deposit s, if they contain co ld boltom -water [au­ nas. most of these form s arc rare and can be regarded as eco logically more restric ted species than the com­ mon hindeodlls species, as n . iypicalis (s weet), h . lotidel/tafus praeparvlis and h _ parl'ffs. these latte r species (and other hindeodus species) arc ecologically very tolerant and could live in environments beyond the ecologi c tolerance boundary of other conodont species. therefore they arc oftcn the on ly conodont species in shallow water environment s, in wh ich gondole ll icl s could not li ve. however, such spec ies wi th very broad fac ies to lerancc are rare o r mi ssing in faunas wit h species that were be tter adapted to a certain facies, e.g. in pelagic fa unas that are rich in gondolc llids or in shal­ low wate r faunas that are ri ch in stcfjallovites kozu r or m errillil/a kozur. for thi s reason , hil/deadl/.\" is mi ssing in srepallovites-ri ch conodont faunas or kazan­ ian shallow water deposits or the russian platfoinl or in shallow wate r zechstein limestones with rich m errilli ­ /1a and slepal10viles faunas despite the fac t that in other places similar shallow water deposits contains exc lu ­ sively hilldeae/us of the h. typicalis group. orchard (1 996) rega rded oceanic cherl s as an example, where "neogondolella" occurs alone. howev­ er, as a radiolarian wo rke r i have invest igated morc than 1000 perm ian oceani c radio la rites ancl red deep­ sea clays rich in deep wate r radio larian faunas. most or these sa mples have no t y ie lded conodonts, but some contain excl usively gondo le llids as mentioned by orchard (1996) . these gondole llid faunas moslly con sist of juveni le specimens indi cating that these oceani c chert s were deposit ed under facial conditions ncar to the ecologic tolerance boundary for gondole l­ lids. ot her samples, however, contain only hille/eodlls of the 1-1. iypicalis group (both juvenile and adult spec i­ mens) and a few samples contain both gondojeliids and i-i ine/(!odlls. the above examples show that the occurrence of hindcoe//ls of the h. typica lis group is not con troll cd by the water depth and by the distance to the coast, but by the presence or absence of be ll er adapted spec ies both '6 in shallow wate r and in deep wate r deposits. the h. typicalis group may be present from vciy shallow water subtidal 10 int raticlal deposits to offshore deep-sea rocks deposi ted below the ceo. t he dominance or exclusive occurrence of the h. typica/is group in many shallow water deposits do not indicate that it is a shallowwater genus but reflect the fac t that this fac ies is beyond the eco logic tole rance boundary of the most ot her con­ odonts (e.g. gondo le ll ids), favouring c lear ly taxa wi th a very high facies tol erance. taxa with such a high facies to le rance, as the h. typica lis group that can be found bot h in very shallow water deposits (w idely distributed at the pit bound,uy) and in deep-sea sediments, in oxy­ gen-rich and in anox ic fac ies (widely distributed at the prr bou ndary), in cold water and in warm wate r deposits (both present at the pit boundary, and having very different non-hindeodid faunas) arc far be tter suit ­ ed for definiti on of any stratigraphic boundary than taxa with res tricted facies to lerance, as gondolejlids that are present only in pelag ic facies (present only in few places in the world near the prr boundary) and more­ over strongly tempera te depcndent w ith diffe rent spec ies in tropica l and hi gh latitude fa unas (as the am monoids). the ccologic model for the di stribution of hinde­ do lls of the h . typica lis group, presented herein, ex pla ins we ll the fac iesre la ted di stributi on of con­ odon ts near the prr boundary in all conodont-bearing complete boundary sections that is in severa l sections in connic t wi th the hindeodlls/"neogondole lla" biofacies model presented by orchard (1996). in meishan, gondole llids are c learl y dominant throughou t the c han gx in g limestone. nindcodus is ve ry rare in th ese beds, among them h . lafidcnfafus fatidcl/ fafus is present that is adapted to warm, deeper water facies. with in the permianrr ri ass ic t ransitional beds the gondolell id biofacies changes into a h indeo­ e/iis bio fac ies. accord ing to thc mode l presented by orc hard ( 1996) this woul d indi cate a shall ow ing within the transiti onal beds compared with the upper changx in g lim eston es . however, thi s is in co nflict with the observed geological data beca use within the uppermost bed of the changx in g limestone a distinc t deepening began tha t cont inued during the transit ional beds. the change from warm water gondo le llid to h il1deodus domi nated faunas is caused by ecolog ic st ress (apparcntl y a short -last ing cooling in the low latitudes because o f the presence of aerosol es ; kozur, 1989, 1994b) that a lso caused the di sappeara nce o f most of the permian spccies in other fossi l groups. this ecolog­ ic stress favourcd the ecologically very tolerant hine/eo­ e/iis o[ the h . fypicalis gro up agai nst the gondo lcl lids despite the fac t that they are beller than h illdcodus adaptcd to pelagic environments. such as the transi­ t ional beds. a similar situ ation can be observed in t ranscauca­ sia and central iran . gondolcllids are clearly dominant in the paratirolifcs beds. above the paralirolifes beds a distinc t deepening is indicated fo r inc reasi ng ly clayey geologia cro:llic:l 49/1 sediments that finall y changed into a red clay. despite of this obvious deepening, the warm water gondole llids arc suddenly replaced by !-lil/dead"s of the !-i. iypicalis g roup co ntemporaneous ly with the disapparance o[ most permian fo ssi ls caused by ecologic stress . the causes are the same as discussed [or meishan. accord­ ing to orchard 's model, a sha llowing would be indicat­ ed for th is level what is against the geological data. in kashmir, the shal low water zewan forma tio n yielded on ly very few conodonts, mostly gondole llids. hilldeodus is dom inant in the deep water lower khuna­ muh formation with rich ammonoid, partly gondole l­ lids arc even absent ; in you nger beds go nd ole llids become dom inant agains t h ille/coe/us . the latte r fac t may be related to the genera l decline of h illdcoe/us near to it s ext inc tion. the dominance of the h . lypicalis group in the ammonoid-bearing part of the lower kllu­ nallluh formation is sure ly not related to shallow-water fac ies for these pelagic beds . the reasons fo r the absence or very rare occurrence of gondo le llids of the c. carinata group (common in all other peri-gondwana pelagic successiosn) in these pelagic beds of the lower khunamuh format ion are not yet known because gon­ dolellids of the c. carinata group are in gene ral not influenced by the cooling event c lose to the r(r bound­ ary. however. thi s fac t shows that also in co ld wate r pelagic facies that is generall y dominated by gondo le l­ lids o f the c. caril/olo group (but !-lil/dead"s o f the i-/. fypicalis group is not absen t in rich fa unas). ecolog ic st ress ncar the prr boundary may cause the total d isap­ pearance of cold wate r adapted gondolcllids. favourin g the occurrence of species o f the h . iypicalis group that are common in these beds. in sicily, uppermost changxingian graded calcaren­ ites with some fu su linids contain a very rich gondole l­ lid fauna and almost no h i1jdeoe/l/s. in the h. par viis zone a slight deeping is indicated fo r shales with a few di sta l graded calcareni tes that con tai n exclu sively h . parvlis. the absence of any other conodont species and the c lear dominance of juveni le h. parvus (adul t speci­ mens a re extremely rare) ind icate that the ecologic con­ diti ons in these deep wate r anoxic to dysae robic beds were near the ecologic tolerance bou ndary for i-i. parvlis and clearly beyond this boundary [or any other conodont species . the overlying prox imal graded cal­ caren ites with conglomera ti c layers indicate a d istinct shallowi ng. but they cont a in h indeodus and gondol e l­ lids. in thi s section, the rocks deposited under the great­ est wate r depth con tajn exc lus ively hilldeodlls, rocks deposited unde r dis tinc tly sha llower water depth co n­ ta in both h indeodus and gondo le llids and rocks depos ited under moderate water depth contain a lmost excl usively gondolellids ind icat ing that the d istribut ion of j-/indeodlls of the 1-1 . typicalis group is not re latcd to the water depth. the permian warm water gondole llicl s are total ly replaced by ii . porvlis because of eco log ic stress (see above) ncar the prr boundmy. the dominance of go ndo le llids in the coo l water peri ~gondwana h . parvus zone can be explained by the kolur: 'inc conodonts f-findcodlls, isarcicdla and sweetohil1deodlls .. . fact that the gondolellids of this level are belter adapted to pelagic envi ronments than hindeodus with very broad fac ies tolerance and the eco log ic st ress in this level (short-lasting cooling event) has mostly not in flu­ ~ nced gondolellids of the c. earinata group because they were adapted (and in this time st ill restricted) to :ool er water. 4. systematic part remark: for often described taxa, only the oldest reference fo r a synonym is given to avoid too long syn­ onymy lists. genus hindeadlls rexroad & furnish, 1964 type species: trichollodella impel/eela rex ­ road, 1957 (=spothognathodus crista/us young­ quist & miller, 1949). synonym: ililchigilathodus sweet, 1970b. remarks: hindeodus displays a sex imembrate apparatus with pa, pb, m, sa, sb and sc clements. car­ boniferous to middle permian pa elements of different l-lindeodl/s species are rather similar and partly overlap in their va riabil ity. however, the rami fo nn clements, and partly the sb elements are different enough to facil­ itate good species separation in those species in which (he pa element is not very diagnostic for separat ion from other species. during the late permi an lopingian series and in the earliest triassic a rapid evolution of the pa element in hindeodus and closcly relatcd genera occurred that is very important fo r the definition of the pit boundary and for the upper permian-lowermost triassic con­ odont zonation (figs. 2, 3). isarcicella kozur (1975) is dist inguishcd rrom l-lilldeodus by a thickening of the cup that commonly bears one or more denticles, or a denticulated side blade on one or both sides of the cup. forms with a thickened ;;up and dcnt iclcs or lateral secondary blade(s) on one or both sides of the cup are typical lsarcicella. forms without dent icles or secondary blade(s) on the cup are tentatively assigned to /sarciee//a, if the cup is th ick­ ened in more than half of its width. if in such form s the thickened part of the clip is narrower than half of the : up width, these forms arc assigned to l-lindeodus (tran5itional {onns to isareicella). according to sweet & clark (1981), isarcicel­ la is probably unimembrate (only pa element). howev­ :1', rich lsarcicella faunas always contain some robust ramifonn elements that may belong to an isarcieella lpparatus. they arc sometimes accompanied also by ~amirorm elcmcnls similar to thosc of l-lindeodus. how­ ::vcr, the frequency of these latter elements is not pro­ jortional to the frequency of the pa clements of lsan·i­ ~·ella , but proportional to the frequency of accompany­ ng hij/deodlls pa clements. a reconstruction of the fsarcicella apparatus is not yet possible, because all 87 known l sarcieella faunas contain also pa elements of hindeodus and other conodonts (mainly ellisonia). therefore it is not known whether the ramiform ele­ ments that occur together with isarcicella pa elements all belong to the accompanying pa elements of hindeo­ dus and other genera (in this case lsareicella would be unimembrate) or whether lsarcieella has an apparatus with robust rarniform elements or an apparatus simi lar to hilldeodus. the latter variant is less probable, because the amount of hindeoduslike rami form cle­ ments is independent from the amount of isarcicella pa elements but proportional to the amount of accompany­ ing hindeodus pa elements as mentioned above. orci-iard (1996) assigned amongst hilldeodu s and it s derivatives all species "with a conspicuous ly elevated cusp, eq ui-dimentional mid-blade denti cles, and abrupt ly terminated posterior marg in " (orc­ hard, 1996, p. 36) to isarcicclla . thickened lateral margin s of the cup and lateral denticles and nodes he regarded as features that may be present or absent. in this scope, isarcicella should begin at the base of th e triassic according to orchard (1996). hc discussed tha t h. parvl/s has a perfect hil1deodus apparatus and pointed out that form s with different platform may have the same apparatus. thi s is correc t, bu t in the casc of neogondolella and clarkin a he rejected on the same page the genus clarkina because the apparatus of this gen us is not known what is not correct because thi s apparatus was already described by kozur (l990b) as he es tablished this ge nus. thc real problem is tha t orchard (1996) compared the hindcodus and isar­ cieella apparatuses by using the apparatus of "isarciee/­ la" pm'va, a hil1deodl/s species, and he did not discuss the view of sweet & clark (198 1) that the type species of isarcicella has no rami form clements. this wou ld be a fundamental difference against all hindeo­ dus species (including h. parvus with hindeodl/s appa­ ratus) that have all a sex imembrate apparatus with pa, pb, m, sa, sb and sc clements, clearly d i fferent from other seximembrate apparatuses. as mentioned above, isarcicel/a may have an apparatus, but if it is present, it would consis t of robust ramiform elements as in elliso­ ilia. i agrce that conodont genera with very d ifferent pa elements may have the same apparatus as t have shown it in several papers (e.g. kozur, 1990b), e.g. for neospathodus and neogondolella, but conodont appa­ ratuses with distinctly diffcrent apparatuses belong always to different genera, the more in thc case of [-lil1deodus and lsareicella that were originally separated by differences in the pa elements. so long no apparatus can be found for l. isareiea, the lype specics of lsarct"­ eel/a, we have to follow the view of sweet & clark (1981) that the type specics of isarcicel/a has no rami form elements. thc tentative assignment of 1-1. pm' viis to isareicella by sweet (1992) was made under the assumpti on that h, parvus has also an appara­ tus wi thout rami form clements. the three "constant" features that define according to orchard (1996) thc genus isorcicel/a arc all fea88 geologia croalica 49/1 series stage substage conodont zone chiosefla gonda/ellaides i neospathodus sosioensis late neospathodus triangularis olenekian neospathodus homer! /criospathodu5 collinson; olenekian neospathodus hungaricus neospathodus waageni early scythogondo/e/la miller! triass ic early neospathodus waageni olenekian ~ scythian scythogondo/el/a? masher! ? chengyuania nepalensis neospathodus cristagalli gandarian n. diener; sz. neospathodus diener; i 8rahmanian ~ "induan" clarkina carinata ellesmer. isafe/cella isarcica hindeodus parvus • conodont-proven in sections 1 or 2 by autochthonous faunas. conodont-proven only by reworked faunas . ? conodont faunas of unproven age . tures that can be observed repeatedly in different car­ boniferolls and permian hindeodlfs lineages . a con­ spicuously e levated cusp is present in some carbonifer­ ous and permian species and the s ize of thc cusp is in some specics a variable feature. equi -dimentional mid­ bladc denticles arc common in several permian species, and an abruptly terminated posterior margin is very characteristic for some middlc permian iilfldeadus spec ies. 1 tend to separate specimens with and without the lattcr feature as di rferent species or subspecies, but wardla w (pers. comm.), who has the greatest expe­ riencc in middle permian llindeadlls, assumes that this feature may represent only intraspeci fic variability (morphotypes) and this opinion may be correct. in any case, if thc three above mentioned features without the thickening of the clisp arc taken as the decisive features or isareieella, then this genu s begins at least in the middle permian. on the other hand, the thickened inner part of the platform is the most important taxonomic feature that never occurs in the hindeodlls stock before the latest permian. it is the decisive feature present in all typical isareieelfa, including the type species and in all species that arc tentatively assigned to isarcicella, as i.? tlirgi­ da (kozur, mostler & rahimi-y azd). there­ fore , it is not understandable, why orchard (1996) wrote that this fcature may be present or missing in isareieel/a . among all species that orchard assi ­ gnedto isareieella , it is only missing in h. parvlfs with a typieal/-lindeodlls apparatus, eonfinning the view that i-/, parvi/s does not belong to isareiee/la, but to hindeo"n. " kummefi sz. i fig . 3 earl y triassic pelagic con­ odont zonation and conodont proven interval in the sec­ tions 350 iii sou th of pictra dei saracini, sosio valley, western sicily. dus. i-t. parvlls is the ancestor of h. paslparvlis, as demonstrated by transitional forms. this species has ne ither equi -dim entional mid-blade denticles, nor an abruptly terminated posterior margin. in some speci­ mens the cusp is not conspicuo usly elevated. an abruptly terminated posterior margin is cven not present in the holotype of h. parvl/s. ii we would use the three "constant" criteria for isareieel/a sensu orchard (1996) for separation from !-lindeodus, then "isare/­ cella" parva would evolve from !-/indeodus (also in the sense of orchard) and its successor would be again a llindeodus. the oldest species with thickened inner platform is i.? prisco kozur from uppermost changxingian beds of the southcrn alps that contain palaeojl(slililla, per­ mian brachiopods, h. lalidenlatf(s praeparvl(s and stepanovites, but no h. parvlls. thus, the !sarcieelfa lineage began within the uppermost permian. this old ­ est representative of the isarcieella stock has, howeve r, neither a conspicuously e levated cusp, nor cqui -dimen ­ tional mid -blade denticles, nor an abruptly te rminated posterior margin. as in the ancestral genus hil/deodl/s, these three features arc not present in all isareieella specics. there is, of course, a possibility to separate species with thickened cup, but without side denticles as an independent genus and to restrict isareicella to forms with side denticles or secondary blade on the thickcned cup. this possibility cannot be exc luded so lon g the apparatuses of these two groups within isareieella can­ not be reconstructed. however, also in this case, h. kozur: 111c conodonts ffilldcodlls.isar('icelfa and sil'l!eloirilldcudiis ... /jarvl/s would remain a hiljdeodlls, because it has no thickencd cup. thc upper permian to lower triassic species of the ii. lypicafis group (inc luding l-i. parvlfs) collectively have some apparatus features that are different from the type hilldeodlls apparatus and from other pre-permian hilldeodus apparatuses. they may be perhaps separated from hindeodus sensu str icto using again the genus aiichigllat!lodlls sweet. but for this consideration the apparatus of the i-lilldeodlls type species must be re­ stud ied. the d ifferences between allchignafhodus and isarcicella would be the same as discusscd for the dif­ ferences between hilldeodlls and isarcicella. hindead"s typical;.\' (sweet, 1970) (pi. i, figs. 1-8; pi. iv, fig. i) 1970a allchigllalliodus typicafis n.sp. sweet, p. 7-8, type material figured in sweet (1970b), pi. i , rigs. 13,20 i 970a ellisollia tcichcni n.sp. sweet, p. 8, 9, type material fi gured in sweet (1970b), pi. 4, figs. 20-28 1977 hilldcadil.\' typicalis (sweet) sweet, p. 223, hilldeodlls pi. 2, fi gs. 1-6 1987 hilldeodils jillfeilsis (swe et , 1973), pars nestell & wardlaw, p. 761-767, only figs. 4.3, 4.6, 4.11, 4.12 description: the pa element is rather long and bears in adults nine to fifteen, but commonly ten to twelve denticles. they decrease in length slowly and more or less gradual ly away from the cusp, which is considerab ly broader, but only somewhat longer than the denticlcs on the blade. the upper edge of the denti­ clcs is directed slight ly downward away from the cusp; but in the posterior third of the unit ei ther a gradual or an abrupt downward curvature is present. there is no distinctly elevated convex hump in the blade. the tips of the denticles arc always free. the cup is large, but not thickened. the rami fonn clements arc described and figured in sweet (1970b) under ellisollia teicilerti sweet. the sb element is especially characteristic. it has a relative­ ly low bar that bears a very large distal or subdistal den­ ticle on the inward curved part o/" the anterior bar. a s hort posterior part of the anterior bar is not curved inward. this part bears one to three small denticlcs. occurrence: upper perm ian, world-wide. tn the boreal realm and in peri-gondwana tethys also in the lowermost triassic, but these latter representatives have slight form dlllerences (e.g. a higher bar and/or differ­ ences in the dentieulation) in some o/" their ramiform clements and may represent an independent taxon with inseparable pa elements. remarks: the pa clement of liindeodus typicafis (sweet) is very similar to that of several cm'bonifer­ ou s and permian species, e.g. l-l. milillfl/s (ellison, 89 1941) to which h. typicalis was previously assigned by most authors. however, the pa e[ement of ii. mint/tlls generally displays a larger "anticusp", commonly with 1-3 denticles that form a rudimentary anterior blade . shape o/" the pa clements of both species however do overlap. the sb element of h. minlltlls is distinctly dif­ ferent. only thc dista l part of the anterior bar is curved inward and the big dista l denticle is missing, as in all other carboniferous to middle permian hilldeodlls species. in h. lotidclltotlis {atidelltatlls (kozur , most­ ler & rahimi-y azd, 1975), the length or the pos­ terior blade of the pa clement is rcdueed, thc denticles arc wider separated and the wide space between the last two dent ieles is through-like and not triangular as the narrower space between the last two denticles of h. lyp­ icatis. in h. latidentatlls praeparvlls n.subsp. the length of the posterior blade of the pa clement is also reduced. adults have 5-7, rarely 8-9 rather broad, triangular, commonly widely separated denticles. the cusp is either about twice as long as the dentic1es or somewhat shorter. the rami form c lements of h. typicafis and h. latidentatlls praeparvlls are similar, but the bars of the sb and sc clements in h. latidentatlfs pracparvl/s are distinct ly shorter. as they are of the same height, their lih ratio is considerably smaller. moreover, inward cur­ vature of the anterior bar of sb elements begins closer to the cusp, without any denticle on the very short hori ­ zontal part between the inward curved part and the cusp. the bar of the sa elemcn t in h. latidelltat!!s pracparvl/s is considerably higher than in h. typicalis. rather regu lar alternations of long and smal l dcnticlcs are present in the poster ior part of the anterior bar oj" the h. lalidelllatlls praeparvlls m clement, whereas in the m clement oj" h. typicalis the length of the denticles alternate irregularly. the pa clement of h . .lui/ells is (sweet, 1973) dis­ plays a distinct, convex, mostly smooth hump in the middle third of the posterior blade (pi. i, pig. 9). the cusp is distinctly longer than the following denticles. in juvenile forms and in transitional forms between h. ryp­ icalis and i-i. jll(jclisis (h. jllilellsis wardlmvi n.subsp.) the hump bears separated denticles . such typical penni­ an forms are st ill present in the boreal ofoceras faunas (sweet, 1976, pi. 16, fig. 9 from the otoceras borc­ ale zone of greenland). forms with a slightly curved upper edge in the posterior half of the blade, but with­ out a distinct hump werc also assigncd to h. ju!fellsis by nestell & w ardla w (1987), but a rc herein assigned to h. typicalis. this assignment is supported by the accompanying rami form e lements , which arc identical with those of l-l. typic'alis. tn contrast, the ram­ irorm elements of h. ju(fellsis (figured by sweet as ellisollia teicheni in teichert et ai., 1973) arc near­ ly identical with those of h. iolidcnfallls praeparvlls (higher bar in the sa elcment, beginning of the inward curved part of the anterior bar of the sb clement imme­ diate ly in fron t of the cusp). 90 hindeodus julfensis (sweet, 1973) (pi. i , fig. 9) 1973 anchignathodus julfensis n. sp. sweet in teichert et a!., p. 426-427, pi. ii, figs. 1014 1973 eliisollia teicherti sweet sweet in tei­ chert et a!., p. 433-434, pi. 12, figs. 1-5 1976 allchigilathodlis typicalis sweet, pars sweet, pi. 16, fig. 9 1987 hindeodus jll/fensis (sweet), pars nestell & wardlaw, p. 761-767, only figs. 4.1 (n. subsp.), 4.2 (n.subsp.), 4.5 (n. subsp.), 4.9, 4.10 (n.subsp.) occurrence: typical h. ju/tensis with a convex smooth hump in adults occurs in the upper dzhulfian (very rare) and lower to middle changxingian (in the central tethys common, but only in warm water pelagic beds). the view of orchard ( 1996, p. 38) that "hill­ deodus juljensis sensu stri cto is a dzhu lfian species" cannot be confirmed. the holotype and all other speci­ mens of h. julfensis published in the original descrip­ tion by sweet in teichert et a!. (1973) were derived from the type dorashamian (= changxingian) of julfa and they occur together with clarkina subcarinata (sweet), the index species of the changxingian. remarks: h . }ulfensis juljensis is restricted to forms in which the pa elements of adulls display a dis­ tinct smooth hump. pa clements of adults with distinct, but denticulated hump are separated as a new sub­ species h. ju/fejlsis wardlawi n.subsp. moreover, the sb clements of the two subspecies arc different. in h. ju/fensis wardlawi, one to three small denticlcs are pre­ sent on the horizontal posterior part of the anterior bar immediately in front of the cusp, whereas in h. ju/fensis jul/ensis this part is adenticulated. differcnces between h. julfellsis and '-i. typicalis have been considered under h. typicalis. h. latidenratlls praeparvlls n.subsp. is closely rehll­ ed to /-1. ju/fensis wardlawi, but the pa clement displays fewer denticles and no distinct hump, and the inward curved part of the anterior bar of the sb clement begins immediately in front of the cusp. the ramiform c le­ ments of /-1. jul/ensis jul/ensis and 1-1. la/iden/allis praeparvus arc nearly identical. only the denticulation of the posterior bar of the sb clement is a li ttle differ­ ent; in h. julfensis jul/ellsis the differences between the large denlicles on the posterior portion of the posterior bar and the smaller dcnticles on its anterior portion are not so strong as in h . latidentall/s praeparvl/s, and the length of thc denticlcs of the posterior bar is morc irreg­ ular. /-/indeadus changxingensis wang, 1995 from the uppermost changxingian to lowermost triassic bound­ ary bed 2 at meishan (south china) has a straight, hori­ zontal, rare ly even backwards rising part with fused denticles that comprises the hump and the largest part geologia croa!ica 49/1 of the blade between the hump and the cusp. only one to four denticles are free between the cusp and the part with fused denticles (in h. julfensis ju/fellsis 5-7, rarely 4 denticles with free tips arc present in this segment of the blade). moreover, the cusp is larger in h. changxin­ gensis (at least three times longer then the following free denticles on the blade). the posterior part of the blade behind the portion with fu sed denticles is com­ monly longer and not so steep ly dipping in h. changxingensis. the undenticulated part of the blade in hindeodus a/tudaellsis kozur & mostler, 1995 is directed obliquely downward like the denticulated upper edge of the blade. moreover, the eusp is only slightly longer than the following denticles. hindeodusju/fensis wardlawi n.subsp. 1975 anchignathodus minutus (ellison), pars kozur, mostler & rahimi-yazd, p. 3, only the specimen on pi. 1, fig. 11 1976 anchignathadus typicalis sweet, 1970, rem i­ niscent of a. julfensis sweet, 1973 sweet, pi. 16, fig. 9 1987 hindeodus ju/fensis (sweet, 1973), pars nestell & wardlaw, p. 761-767, on ly figs. 4.1, 4.2, 4.5, 4.10 derivation of name: in honour of dr. b. w ard­ la w, reston, for hi s outstanding work on permian conodonts. holotypc: the specimen figured by nestell & ward la w, fig. 4.5. locus typicus: hydra island (greece), locality 9599 according nestell & w ardla w (1987). stratum typicum: upper wuchiapingian limcstone with clarkina orientalis (barskoy & koroley a). diagnosis: the pa element displays a distinct, but denticulated hump. the sb element bears one to three small denticles on the horizontal posterior part of the anterior bar. description: the pa clement displays a distinct cusp, that is two to three times longer and considerably broader than the nine to thirteen small denticles of the blade. the upper edge of the denticles is s lightly inclincd in its anterior part, then horizontal and a strong downward curvature is present in the posterior third. at the beginning of this downward curvature a distinct, convex, denticulated hump is present, in which the inclination of the dentic1es becomes rapidly stronger; the last denticle of the blade may be directed backward. the cup is wide, but not thickened. the ramifonn clements arc typical for upper penni ­ an hindcodus. they are well described in nestell & wardlaw (1987, p. 763, 765); only the taxonomi­ cally important sb clement is re-described herein. it has a planar posterior bar with cight small dcnticles behind kozljr: 111c conodonts /iil/deodlls, fsari'icdla and s\\'cc/olrindevdlls ... the cusp that are only vcry sligh tly inclined, followed by two to four stronger inclined denticles. the last den­ ticle is in gencral smal l. the cusp is large, nearly erect. the short planar posterior part of the anterior bar bears one to three small dcn ticles. the remaining part of the anterior bar is directed inward. it bears several small , and distally or subdistally one large denticle. occurrence: upper dzhulfian, rarely in the changxlnglan. remarks: h. j[{~fellsis wardlawl is transitional between hilldeodus typicatis (sweet, 1970b) and !-i. jllifellsis (sweet, 1973). in h. typicatis, the cusp of the pa clement is smaller and the upper edge of the den­ ticles is directed downward on the entire blade, whereas in ii. ju(jcllsis ... vardlawi the upper edge of the denticlcs is horizontal in the middle part of the blade. t he rami­ form elements of h. typicalis are similar to those of h. j[{l/ellsis wardlawl, but the bar in the sa element is low­ er and directed more dowllward in !-i. typicalis. the hump in the pa element of i i. juljclisis jll!fellsis is always smooth in adult specimens. in juvenile speci­ mens (e.g. sweet in teichert et ai., 1973, pi. 11, fig. 10), it may be denticulated and such forms are (except for their smaller size) inseparable from the pa element of f-i. juuciisis wardlawi. however, the sb ele­ ment of h. jill lei/sis juf/ensis is different. it is shorter, higher and the very short, not inward inclined posterior part of the anterior bar bears no denticles. moreover, the bar of all ramiform elements in h. jll!fel/sis jll!fel/sis (figured by sweet in teichert et a i. , 1973 as elfisojlia leicherti) is higher and above all the length:hcight ratio is considerably smaller. i-lil/deodus latidentaws (kozur, mostler & rahimi-y azd, 1975) has no hump. in the pa element of h. lalidel/tallfs praeparvlis ll.subsp., the denticlcs of the blade are larger, their llumber is smaller and their size is commonly more differentiated (small and slen­ der behind the cusp, larger and above all broader in the posterior half of the blade), but there are also forms, in which the all denticles except the clisp have nearly the same size. the pa element of fl. latidel/tafus fatiden/a­ ius is additionally distinguished by the widely separat­ ed, broader dcll!iclcs. in the sb element of 1-1. laridento­ flfs praeparvlfs, there arc no denticlcs between the cusp and the immediately following inward-curved part of the anterior bar. hindeodlls lalidell/a/lls (kozur, mostler & rahimi-y azd, 1975) (pi. i, figs. 10, 11; pi.u, figs. 1-4) i 970a allchignathodlfs typica/is n.sp., pars sweet, p. 7-8 , pi. i, fig. 22 1970" ellisonia teicherti sweet, n.sp. sweet, pi. 1, figs. 3, ?8 1975 anchigllathodus latjdentaflls n.sp. kozur, mostler & rahimiyazd, p. 4-5, pi. 2, fig. 6 91 1976 anchignathodus typicalis sweet, pars sweet, only the specimen on pi. 16, fig. 7 ?1979 anchignathodlls parvlis kozur & pjatako­ va wang & wang, p. 116, pi. 1, fig. 20 1981 hilldeodus minlltus (ellison, 1941), pars matsuda, p. 78-91, pi. i, figs. 1, ?3, 4, 6, 9, 12; pi. 2, figs. 1,5-7, 1j; pi. 3, figs. 1-3,5-7, 10; pi. 4, figs. 2, 4, 7,11,12 1985 hindeadlls latidelllalus kozur, p. 238 1987 hilldeodus typicalis (sweet, 1970), pars perri & andraghe'iti, p. 308-309, pi. 32, fig. 3 1991 hilldeadus typicalis (sweet, 1970), pars perri, p. 40-42, pi. 3, figs. 2, 5 1991 hindeodus cf. latidentatus (kozur, most­ ler & rahimi-yazd) schonlaub, pi. i, fig. 9 1991 hindeodlls pm'vus (kozur & pjatakova, 1975) pars sci-ionlaub, only pi. i, figs. -18, "13 1994 hilldeodlls latidelltatus kozur, mostler & rahimi-y azd orchard et ai., p. 836, pi. i, fig. 20 1996 hilldeodus "latidentatus" (kozur, mostler and rai-iimi-yazd), 1975, pars mel, p. 146, only pi. 2, fig. 5 1996 l-lindeodlls typicalis (sweet, 1970), morpho­ type 1 mel, p. 146, pi. 2, figs. 8, 9 occurrence: upper changxingian and lowermost triassic, worldwide. remarks: the holotype of h. fatidellf({fus repre­ sents a rare form with widely separated dcnticles, in which the last i wo large clentic1es are separated by through-like spaces. in j984 i had prepared a manu­ script describing morphol ogic transitional forms between h. typicatis and h. parv/./s as a new species h. praeparvus. during finishing that manuscript, i found transitional forms bel ween this assumed new species and f-i. faridentatlls. as i could not definitely separate these two taxa in thai time, i used f-i. latideljtatus in an emended sense to include the morphologic transitional forms between i-i . iypicafis and /-i. parvus . during a long written and personal discllssion with dr. m. orchard, vancouver, we agreed that both forms are independent taxa that may be separated despite the presence of transitional forms throughollt the range of both taxa. because of the presence of these transitional forms and the fact that their spatial separation is rather facies-controlled, i separated the morphotype prae­ parvlfs only as subspecies that corresponds roughly to hilldeodus n.sp. x sensu orchard (1996). dr. orchard insisted that i should publish this taxon alone. according to orchard (1996), i-i. latidentatlls latidentatlls (/-1. latidentatus sensu orchard) has a diffe rent range (upper changxingian) from h. faridelln talus praeparvus (hindeodus n.sp. x sensu orch­ ard) thai he res tricted to the lowermost triassic. howeve r, these ran ge differences are largely facies­ controlled. h. lalidenla/lis latidel/talus is restricted to warm water pelagic deposits, in which h. {atideniatus praeparvlfs is very rarc. however, both taxa are present in the upper changxi ng limestone, even the rare mor­ pholype 1 of h . latidef/tatus praeparvlfs (mel, 1996, pi. 2, figs. 5, 9) occurs. on the other hand, the holotype of ' -i . latidentatus latidentafus was derived from the lower part of the transitional beds in the iran that has the same fauna as the lower transitional beds in south china. according to orchard (1996) the lower transitional beds of soulh china have triassic charac­ ter, but are assigned here in (i n agreement with most workers) to (he uppermost changxingian because h. parvus, the index spec ies of the lowermost triass ic, evolved only in the midd le part of transitional bed 2, and the [ower transitional beds contain typical permi­ an ammonoid, brach iopod and conodont taxa. h. lati­ del/fafus lafidel1falus is absent in the upper transi tional beds (with first 1-1. parvlts) both in south china and in iran, whereas h. latidejifatus praeparvlis cont inues in these beds with decreasing frequency, but is no longer present above the lower range of h. parvus. these slight diltcrcnces in upper range may be caused by the low number o f /-1. lalidelllallis lalidejifallfs evcn in the time of the maximum frequency of h. lmidelltatlls. the relations or h. latidel/tatus to other taxa will be discussed under the subspecies. hindeodlls latidentatus latidelltatlls kozur, mostler & rahimi-yazd, 1975 1975 allcliigllatliodus latidelltalus n.sp. kozur, mostler & rahimiy azd, p. 4-5, pi. 2, rig.6 1985 hilldeodlls imidelltatlls, pars kozur, p. 238 1994 hilldeodl/s latidentatlls kozur, mostler & rai-iimi-y azd orchard et a!., p. 836, pi. 1, fig. 20 1996 hilldeodlls "iatidelltatlls" (kozur, mostler and rai-iimiy azd), pars mel , p. 146, only pi. 2, fig. 5 1996 h illdcodlls typicatis (sweet), pars yin & zhang, only the specimen on pi. 8, rig. 4 description: only thc pa clement is known. the cusp is largc, slender triangular, about twice as long as the denticlcs on the bladc. the [cngth of the denticlcs increases a little in posterior direction, only the last denticle is mainl y short. two or three dentic les adjacent to the cusp are slender, denscly spaced with v-shapcd spaces betwecn these denticlcs. the following three denticlcs arc triangu lar and often very broad. thc d is­ tance between the postcrior three dentieles (if a very small last denticle is present) or between the posterior two denticles (if no very small last denticle is present) is very large and the space between these denticle is ugeologia croatica 49/1 shaped. the basal cavity is expanded and comprises the entire lower side of the blade . on ly below the clisp a broad basal furrow is present. occurrence: upper changxingian (including lower tran sitional beds) of northwestern and central iran, azerbaidzhan-transcaucasia and south china. always rare. rest ricted to warm water pelagic facies. remarks: the above descript ion corresponds to the ori ginal scope of the species. later, the rare and appar­ ently facia lly restricted h. lalidenlatus latidel/talus was regarded as an extreme variant of the world-wide d is­ tributed and common morphologic transitional forms between h. typicalis and i-i. parvlis. all h. lafidelltaths figured after kozur et al. (1975) were in reality these transit ional forms, herein dcscribed as h. lalidenfaflls praeparvus n.sp. only orchard e t a!. (1994), mel (1996) and yin & zhang (1996) figured again a fl. latidentallis sensu str icto from thc mcishan scction of south china. orchard et al. (1994) recognized that thi s specics has not a big variability including also the ancestors of h. parvuos, but also the chinese forms have thc dcnticu lalion type of the northwestern iranian{fran­ scaucasian lype material. moreover, they recognized that th is species in its original scope is restrictcd to the upper changxingian. however, thcy assumed that h. lotidenlallls latidelltatus is restricted to the upper changxing lim cstone of south china and the time­ equivalent paratirolites beds or iran. howevcr, h. lati­ dentaflis latidentatlls is also present in the lower transi­ tional beds of both areas, and also the ho[otype was derived from th is stratigraphic level. mel (1996) rcgarded fl. latidcntatus s.str. (~ /-1. lafidel/latus latidentatlls) as rarc morphotypcs of both h. typicalis and h. parvl/s . however, h. lalidclltatlls latidentatlls does not occur together with h. parv[{s, and consequently cannot be a rare morphotype of h. parvlis. the specimen from the h. parvlis zone or selong that mel (1996, pi. 2, fig. 7) figured uncler h. "la/idenlatlfs" is one of those lowermost triassic forms assigned in previous papcrs to h. typicalis that belong to new taxa. its denticulation (the largest denticles arc situated immediately behind the cusp) is totally differ­ ent from both i-i. latidel/lallls and t-i. lypicalis . accord­ ing to its denucldation, h. latiden!allls laridewatl/s can be only a rare morphotype (restricted to pelagic warm watcr dcpos its) or t-i. lalidelllatils postparvlis, as t havc assumed for many years. but sllch facially and partly also geographically separated morphotypes can be regarded as different subspecies as in the present paper. yin & zhang (1996) assigned a specimen of h. latidentatlls latidewlfs to h. typicalis (sweet), but the wide, u-shaped spaces bctwecn thc largc last threc den­ tic1es are never present in f-i. ,ypicalis. hindeadus latidenlatus praeparv//s n.subsp. has a variab[c denticulation. commonly, it has the same suc­ cession of the denticles on the blade as in h. latidellta­ ius latidell/{{lus w ith two, rarely three sma ll cr and above all slender, closely spaced dentielcs followed by km:lir: cill<o: conod0l11s ftil/deadl/.\' . fs(jrcicclla and swee!()liilldeodu)' .. . bigger and above all broader denticles with wider inter­ denticle spaces, commonly followed by a small denti ­ cle. however, the inter-denticle spaces between the last three denticles are v-shaped. exceptionally the space between the last two denticles may be u-shaped. these forms may be transitional fomls to h. latidcntatlls la/i­ dellfaflls, but this feature occurs sometimes also in l-l. {jarvl/s. hindeodlis lalidenlallls praeparvlls n.subsp. (pi. i, figs. 10, 11; pi. ii, figs. 1-4) 1970a allc/zigllat/zadus /ypicalis n.sp., pars sweet, p. 7-8, pi. i, fig. 22 1970a ellisollia leicherli sweet, n.sp. sweet, p1. i , figs. 3, ?8 1976 anchigllatllodi/s typicalis sweet, pars sweet, only the specimen on pi. 16, fig. 7 ?1979 allchigllall/odlls parvlls kozur & pjatako­ y a wang & wang, p. 116, pi. i, fig. 20 j981 hilldeodlls millllllls (ellison , 1941) , pars matsuda, p. 78-91, pi. j, figs. i , ?3, 4,6,9, 12; pi. 2, figs. i, 5-7, ii; p1. 3, figs. 1-3, 5-7, jo; pi. 4, figs. 2, 4, 7,11,12 1985 /-lindeadus latidentatus. pars kozur, p. 238 1987 nilldeadlls iypicalis (sweet, 1970), pars perri & andraghetti, p. 308-309, pi. 32, fig. 3 1991 i-lilldeodlls iypicalis (sweet, 1970), pars perri, p. 40-42; pi. 3, figs. 2, 5 199[ llilldcodlls cf. lalidenlallls (kozu r, most­ ler & rahimi -y azd) schonlaub, pi. i , fig. 9 1991 hindcodns parvlls (kozur & pjatakoy a, 1975), pars schonlaub, only pi. i, figs. '18, ., 13 [995b hindeodlls lalidenlallls (kozur, mostler & rai-iimi-yazd) kozur, p. 67-69, pi. i, fig. 5-8; pi. 2, figs. 2, 3 [996 hindcadlls " ialidell/allls (kozur , mostler and rahimt-yazd), [975, pars mel, p. [46, only pi. 2, fig. 5 j 996 hilldeodlls iypicalis (sweet) , 1970, morpho­ type i mel , p. [46, pi. 2, figs. 8, 9 derivation of name: assumed ancestor of 1-1. parvlfs. holotype: the specimen on pi. ii , fi g. 2, rep.-no. ko 9003, rep. -no. ko 8992. type locality: tesoro (southern alps , italy), type locality of thc tesero oolite. type stratum: tesero oolite, 1. 5 m above the bell crophon limestone, 0.5 111 be low the horizon with changx ingian brachiopods, upper changxingian. diagnosis: the pa element is rather small and bears :ol11monly five to seven dentic1cs that have all approxi93 mately the same length (except a commonly present small denticle at the end of the blade), but two to three denticles behind the cusp are commonly more slendcr than the broad denticles in the posterior hal f of the blade. but the dentieles may have the same size on the entire blade. the spaces between the denticles are v­ shaped, only exceptionally u-shaped between the two last dentic1es. the cusp is broader and considerably longer than the [allowing denticles (commonly around twice that of the denticl es on the blade). the cup is wide, but not thickened. two morphotypes are present distinguished in denticulation and the height of the pos­ terior end. description: the apparatus is seximem brate. the pa element is relatively short and bears five to seven, rarely e ight to nine triangular, mostly broad dcnticles that are often widely separated. in the rare morphotype 1 the denticles are approximately of equal length and width, relatively narrow, straight or slightly and uni­ formly inclined , and the very high posterior end or the posterior blade is undent iculated. in the common mor­ photype 2, the denticles are broadly triangular, widely separated, almost or equal length, but the first two-three denticles after the cusp are commonly distinctly nar­ rower and closer spaced. sometimes, all denticlcs are of nearly the same shape and the space between them does not change in the entire blade. the denticulation reach­ es close to the low or modcrately high posterior cnd of the blade. both morphotypes are connected by transi ­ tional forms, in which all the aforementioned featu res may be transitional. in both morphotypes the spaces between the dentieles are v-shaped. very rarcly the space between the last two denticles is u-shaped . the cusp in both morphotypes is broader and cons ide rably longer than the following denticles (commonly around twice that of the dcn ticles on the posterior blade) . the cusp and the denticjes are striated. the clip is widc, but notlhickened. the rami form clements (pb, m, sa, sb, se) arc fig ­ ured and described by matsuda (198 1) under i-iin­ deodus min "'us (ellison, 1941), see synonymy list. they are similar to those of l-l. typicalis, but the bar of the sa clemcnt is highcr. the anterior bar of the sb ele­ ment immediately in front of thc cusp is strongly curved inward. there are no dentieles between the cllsp and the inward curved part of the bar. the posterior bar is high and bears three to five large denticles in the pos­ terior half and three to four small denticles in thc antcri~ or hal r. occurrence: world-wide distributed in the upper­ most changxingian, rarely also in the lowermost triassic. remarks: the ancestor of hilldcodus latidcnla/us praeparvl/s n.subsp. is e ither h. ju(fellsis wardlawi n.subsp. or a representativc of l-l. typical!s (s weet , 1970b) with somewhat larger cusp. h. latidentatlls praeparvlfs and 1-1. julfensis wardlawl both display a large cusp on the pa element and the ramiform elcments (except the sb element) arc nearly identi cal. only the 94 sb element of h . julfellsis wardfawi is more similar to that of h. typicalis because the short horizontal posteri­ or part of the ante ri or bar displays 1-3 small denticles and the posterior bar d isplays 10-13 dcnticlcs, from which the last 5 clen ti c les arc not so large as in the sb clement of i-/. [atidentatlls praeparvl/s. in h. t),picalis (sweet, 1970b) (form s with some­ what larger cusp), the pa clement has more clenticles (915) that are genera ll y morc sle nder and not so widely separated as in morpholype 2 of h. /atidentatl/s. and not so uniform in length as in morphotype 1 of this species. additionally, the bar of the sa element and generally also of the sc element is lower, and the sb clemen t di s­ plays a shaft horizontal posterior portion of the anterior bar w ith 1-3 denticles bet ween the c usp and the inward cu rved part. s ome au thors have consi de red i-/. lafidcfllalus praeparvlls as well as h. typicalis as synonyms of h. mil/i/tlls (ellison, 194 !). however, both have differ­ enl pa and sb elements. in the sb e lement of n . miflll ­ tus only the anterior portion of th e anter ior bar is curved inward and has no big denticle. h. /atideflta/us praeparvlis was also sometimes referred to i-lil/deadl/s parvl/s (kozur & pjatako­ v a, 1976), e .g. by wang & wang (1979) and schonlaub (1991). but in /-i. parvlis the cusp is considerably longer (more than twice that of the follow­ ing dentic les) and is generally a lso more slender. the rami form e lem ent s of 1-1. parvlls are dis tinguished by shorter and re lative ly higher bars in all elemen! s (except the sa clement that has already in 1-1. latidenta­ t/ls pracparvlls a ve ry high bar) ; in the sb clement the c usp and generally also one denticle behind the cusp lie on the inward curved part of the unit. h. /rrtidellfatus praeparvlls (:::; i-lin deodus n.sp. x sensll orchard, 1996) is thc ancestor of hil/deadl/s parvl/s. all transitional forms are present between these two spec ies in s tratigraphic sequence. orchard ( 1996) ques tioned this deri vation because the overlap­ ping ranges of these two taxa, but thi s view is hardly to understand. in all well docume nted phylomorphogene­ ti c clines of conodonts and in most clines of other micro fo ss il s an overlap o f different duration between the range or the ancestral and succeed ing forms is pre­ sent , if thc re is no strati graphic break or abrupt fac ies change between the occ urrences of these forms. some­ times the uppe r range or the ancestral form exceeds even the range of the succeeding form (as for h. fypi ­ calis, the ancestra l form of th e changxingianiower­ most triassic hindeodid stock). h. /atidcjltatus praepa/'vlis is also the fore runner of th e upperrnost changxingian isarc icellrr ? prisca kozur, 1995a. these two species display the same denticulation of the blade and the same relative size of the ellsp with respect to the following dcilticles 011 the blade. however, the inner part of the clip in i. ? prisca is clearly thickened, as in typical/sarcicella. isarcicella? lurgida (kozur, mostler & ra ­ j-iim1-y azd, 1975) from the lowermost triassic disgeologia croatica 49/1 plays a distinctly thickened inner part of the cup of the pa element and the cusp is distinctly lon ger than the denticles of the blade (in general more than twice). hindeodlls parvlls (kozur & pjatakova, 1976) (pi. ii , figs. 5-8; pi. iii , figs. 1-11; pi. iv, figs. 5-7) 1964 spathognathodus isarciclis huckriede, 1958, pars staesci-ie, p_ 288-289, only figs. 60, 61 1970a ell isollia teicherti sweet, n. sp_, pars sweet, p. 8,9, only pi. 1, fi g. 7 1975 allelligl/atflodus parvus kozur & pjatako­ va n. sp., pars kozur , p. 7-9, pi. i, only figs. 17,2 1, 22 1976 ajlchignathodus parvils n.sp., pars kozur & pjatakova, p. 123-125, only figs. la, b, e, h 1977 f sarcicella isareico (huckriede), pars sweet in ziegler, p. 229-230, morphotype 1 in text-fig ure "terminology of isarcicella kozur, 1975" at p. 225 1981 i-lindeadll s parvlis (kozur & pjatakov a, 1975) matsuda, p. 91 -93 , pi. 5, figs. 1-3 1981 hilldeadus mil/utll s (ellison), pars mat­ suda, p. 78-9 1, only figs. pi. 1, figs. 8, 10, 13; pi. 2, fig. 8; ?pi. 3, fig. 4; opi. 4, fig. 9 1992 isareicella ?parva (kozur & pjatakova)­ sweet, p. 125 1995 hilldeodus latidentatlls (kozur, mostler & rai-llmi-y azd), pars metcalfe, only the specimen on pi. 2, fig. 7 1996 hil/deodus parvus (kozur & pjatakova), mojphotype 2 kozur et ai. , p. 206-207, pi. 1, fig. a 1966 !-lindeodlls parvus (kozur & pjatakova) , morphotype 1 kozur et ai., p_ 206-207, pi. 1, figs. b, g description: apparatus seximem brate. the pa ele­ ment is small and displays a very big, rather slender , erect or s lightly backward inclined or curved cusp. the following four to nine denticles are less than one-half as large as the cllsp. in h. pm-viis erectus (:::; morphotype i of h. parvlis) the dentieles are slende r, small, erect, and all nearly of the same s ize. the posterior part of the blade is steeply inclined and either undenticulated or it bears in the upper part a small denticle that is col11mon­ ly presem at least in adult forms. h. parvus parvlls (:::; illorphotype 2 of h. parvus) di splays erect, but s lightly longer dentie les, the upper profile is s light ly backward incl ined. the posterior thi rd of the blade is occupied by three, rarely two smal l, st rongly inclined de nticles . transit ions occur between bot h forms in the lower part of their ranges. the cup varies from moderately wide to wide, but is not thickened . the ramiform elements (pb, m, sa, sb, sc) of h. parvl/s are typical for hindeodus, but the bars are re la­ tively shon and high. (owr: "!lil: conodonts hilldeodlls. isarcicella alld swt't'whil!(leodlls ... the pb clement displays a very short anterior bar .vith one or two denticles. the posterior bar is short and very high and bears dcnticles of irregular size. it shows 1 slight torsion. the cusp is large, especially broad. the ower side displays a narrow basal furrow and an elon­ sated, but not very wide basal cavity. the m clement displays a long and very high anleri­ )f bar, whereas a posterior bar is missing. the distinctly lilward curved cusp is relatively narrow, moderately long, but not much longer than the longest denticles on .he anterior bar. the anterior bar bears in it s anterior ~art twelve to thirteen small, needle-like, densely ;paced dcnticles of approximately the same size. tn the posterior part of the anterior bar, the small to moderate­ ly long needle-like denticles alternate regularly with long, needle-l ike denticles. the four segmen ts with lhree to four small to moderately long dentieles between the long den ticles are about equal in length. in general five long denticles are present, the first one lies immediately behind the cusp. the lower side is some­ what inverted and below the cusp abovc the basal cavi­ ty distinctly curved upwards. the basal furrow is very narrow and indistinct. the sa element is symmetrical and very high. the lateral bars are relatively short and bear only six to sev­ en denticles of irregular size, but beside the cusp there arc always one or two small dent icles and the penulti­ mate denticle is a l ways large on both side bars. the cusp is relatively small and not much larger than the largesl denlicles on lhe side bars. the lower side is dis­ tinctly inverted, but a small pit and an indistinct basal furrow are present adjacent to the pic in the sb element the strongly inward-curved part comprises not only the antcrior bar or its anterior por­ tion, like in most other hil/deodus species, but also the moderately large cusp and someti mes even the first denticle of the posterior bar. the terminal/subterminal denticles of the anterior bar are somctimcs not mllch larger than the remaining denticles, but there are also sb elcments with large denticles on the posterior part of the anterior bar. the posterior bar is high and short and displays very large posterior denticles that arc common­ ly longer and broader than the cusp. the lower side is strongly inverted and displays an inciistinct, small pit. the sc element has a short, but high, sl ight ly inward and somewhat downward curved anterior bar with two needlelike, small, erect denticles in front of the cusp and a moderately large, terminal denticle that is more strongly forward inclined than backward :::urved. the cusp is vely long, but slender. the posteri­ or bar is high and bears marc than twenty, backwards inclined , needle-like denticles of irregularly varying size. the lower side is somewhat invertcd and has a vcry sma ll pil below the cusp that continues into a very ilarrow basal furrow. occurrence: hindeodlls parvlis and {sareieella isardea zones of the lowermost triassic. world-wide. 95 remarks: staesche (1964) regarded lhe pa ele­ mcnt of h. parvus as an undenticulated illorphotype of isarcicella isarcica. kozur (1975) and kozur & pjatakova (1976) recognized lhal (his form appea­ red earlier than i. ism'dca and estab li shed the new species anchignathodus parvus, which was later ass igned lo hindeodus. sweet (1977) again regarded h. parvlls as a morphotype of i. isarcica, and was fol ­ lowed by perri & andragi-ietti (1987) and per­ ri (1991). sweet (1992) subsequently agreed lhat i-i. parvus is an independe nt species, but assigned it to (sardcella ?parva assuming that h. parvus is unimem­ brale as i. isarcica. he was followed by orchard (1994, 1996) and orchard et al. (1994). the discov­ cry in sicily of a rich monospecific fauna containing the entire apparatus of h. parvlls, has confirmed the view of kozur (l977b) lhal h. parvus has a hindeo­ dus type apparatus (then assigned to its junior synonym allchignathodus). this fauna was found in a permian­ triassic boundary section 350 m south of pielra dei saracini (sosio valley, sicily, italy, see gullo & kozur, 1993) in thin fine-graded limestone intercala­ tions (distalturdidites) within a 2 m thick anoxic clay at the base of the triassic. all e lements have shorter and re latively higher bars than the carboniferous and most of the permian hindeodus species. otherwise the rami­ fo rm element's are sim ilar to those of h. fypica/is, h. latidentalus praeparvlls and 1-1. jllilel/sis, but can bc mostly distinguished at species level. in the immediate forerunner, h. lafidentatus praeparvlfs, some elements (sa and sb clemen ts) already have the same high and shorl lype of lhe bar; lhe sb elemenl already has a rather hi gh bar in h. typiealis. advanced representatives of h. parvl/s commonly have 1-3 small denticles at the anterior edge of the clisp that may form a short , low anterior bar. such forms were described as anchignathodus al7ferodelltallls in dai & zhang (1989), but are considered herein as a subspecies of h. parvus. /-t. parvlfs evolved from 1-1. lalidental//s praeparvus n.subsp. by development of a smaller pa clement with bigger cusp and by development of shorter and relative­ ly higher bars in al l rami form clements. the sa clement is also very high in h. latidentatlls praeparvlis and h. julfensis, but bears more denticles (9-10 on each side bar). the sb clement of h. latidentatus praeparvl/s is also as high as in h. parvus, but the inward curved part of the anterior bar begins shortly before the cusp that is situated, as the posterior bar, on thc planar part of the clement. a very impressive phylomorphogenetic lin ­ eage can be observed in the sb clcments from h. rypi­ calis to h. parv//s. in h. typicalis, the posterior bar and a short posterior part of the anterior bar wi th three to four denticles is p lana r and the inward curved part of the anterior bar begins therefore d istinctly before the cusp (pi. 1, fig. 7). in h. fatidenlallls the inward curved part begins a little before the cusp, but no denticles are present between the cusp and the inward curved part (pi. 1, fig. ii). in h. pm·vlis not only the anterior bar, 96 but also the bar below (he cusp and commonly also below the anlcriofmost denticle of the posterior bar arc curved inward (pi. ill , figs. 6, 10). the pa e lement of hincleodus fjostparvus kozur, 1990 is distinguished from that or /-1. porv[fs by the symmet rically arched upper profile of the blade. the denticles are largest in the mid -length region of the blade or somewhat behind it and have strongly dive r­ gent inclination. the m clement of ii. postparvlls is dis­ tinguished from that or all other hindeadus species by the presence of a denticulated posterior bar. the strati­ graphically youngest representatives of h. parvlfs with vcry small pa element (that occur together with h. posf­ parvlfs) display also a m element with dcnticulated pos­ terior bar. alternatively, all apparatuses with denticulat­ ed pos terior bar of the m clement belong to n. posi ­ parvils or the apparatuses with a small h. parvlis pa eleme nt and a h. postparvils m element belong to a new spec ies, tran si tional between i-/. parvlfs and h. postparvus. isarcicella isarcica (huckriede, 1958) is distin­ guished by thickening of the cup and development of a denticle or a secondary blade on one or both sides or th e thic kened part of the cup. moreover, isarcicella isarcica displays either an apparatus consisti ng only of pa clements or the lsarcicella isarcica apparatus con­ tains robust rami form clements that generally accompa­ ny the isarc/cel/a pa clement. in both cases the appara­ tuses 0(" i-i. parvlls and 1. isarcica are very different. three subspecies, h. parvus parvlfs, h. parvlls anlerodentatlls and h. parvlis cree· ius n.subsp. are dis­ criminated within h. parvlis. hindeodus parvlls parvlls (kozur & p jatakov a, 1976) (pi. ii, pig. 7) 1975 allchigllathodlls parvlis kozur & pjatako­ v a n.sp., pars kozur, p. 7-9, pi. i, only fig. 22 1976 anchigllathodlls parvils n. sp ., pars kozur & pjatakov a, p. 123-125, only fig. i b 1981 hilldeodlls millll/lls (ellison, 1941), pars­ matsuda, p. 78 -91 , pi. i , only fig. to 1981 i-iilldeadlls parvlis (kozur & pjatakova, 1975), pars mats uda , p. 91-93, pi. 5, only fig. 3 1990a hilldeodlls parvlis (kozur & pjatakov a, 1976), morphotypc 2 kozur, p. 400 description: sec at i-i. parvus. the pa clement is small and bears eight to nine denticles; their upper pro­ rile line is somewhat backwards inclined. the posterior steeply inclined high part or the blade bears three, rarely two small dentieles. ramiform elements as for the spec ies. geologia croalica 49/1 occurrence: j-f. parvlis zone to slightly above the i. isarciea zone of lowermost triassic. j-f. parvlis parvus is not as facies tolerant as h. parvus ereelus. there[ore it is missing in anoxic or dysaerobic beds, in which h . parvus ereelus is commonly the only present conodont taxon and onen the only fossil. remarks: hindeodus parvlls erectus n.subsp. di s­ plays 4-7 denticles with a commonly straight, horizon­ tal upper profi le. the steeply dipping to vertical high posterior end is smooth or bears one small dentic le (commonly in adult forms). in hilldeodus falidenlallis praeparvus n.subsp., the pa clement is larger and the cusp relatively shorter and broader. the dentieulation is very si milar in many spec­ imens (common morphotype 2 of h. fatidenlalus praeparvlis). the ramiform e lements are comparable, but longer and except in the sa and sb e lements the bar is lower. the inward bent of the sb e lement begins in front of the cusp that is always situated on the planar part of the bar. the pa element of j-f. poslparvlls kozur , 1990 is similar, but the inclination of the denticles is more strongly d ivergent and thei r upper profile line is con­ vex. the m clement is distinguished by the presence of a denticulated posterior bar. hindcodlls parvus anterodeniatus (dal, tian & zhang, 1989) (pi. tv, rig. 5) 1989 allcilignalhodus anterodentatlls dat , ttan & zhang (sp.nov.) dai & zhang, pi. 45, f igs. 14, 15; non! pi. 48, figs. 10, ii 1993 hindcodus anlerodelltatus oat & ttan gul­ lo & kozur, fig. 2.1 i 1995 hil/deodlls pm·vlls (kozur & pjatakova), pars metcalfe, pi. 2, figs. 73,4 occurrence: isarcice/la isarcica zone. world­ wide. j-j. pan-'ll."· anterodentaflls appears at the base of the i. is-arcica zone. in the absence of the index species (e.g. in greenland) the first appearance of i-i. parvus allterodel/latus is a suitable marker [or the base of the i. isarcica zonc. remarks : the presence of one to three denticles on the anterior edge of th e cusp is mostly without taxo­ nomic importance in carboniferous and permian hin ­ deodus species. however, in h. parvus this feature occurs only in forms from the i. isarcica zone. there­ fore, thesc form s are regarded as an independellt sub­ species. as /-1. parvlls anterodenratlls is always accom­ panied by other hilldeodus species, the rami[orm ele­ ments of its apparatus cannot be assigned with certai ni ­ ty. they may be comparab lc with those of the other subspec ies of h . parvus, but the sc clement may be morc advanced (see remarks to h. poslparvlls). kozur: 111c conodonts liitl(l{'q(llls . l.mrdcdla and swcclohindcadus .. . flilldeodus parvils erectlls n. subsp. (pi. ii. figs. 6, 8; pi. fii , figs. iii ; pi. tv, rigs. 6, 7) 1964 spolhogl/athodl/s ism'cieus huckriede, 1958, pars staesche, 288-289, only figs. 60, 61 1975 ai/ehigl/athodll s parvus kozur & pjata ­ kov a n. sp. , pars kozur, p. 7 -8, pi. i , only fig. 17 1976 allclligjlolhodus parvl/s n.sp. , pars kozur & pj atakoya, 1'.123-125, only fi g. la 1981 i-lil/deodlls iliilll/llls (ellison , 194 1), pars mats uda, p. 78-91 , pi. 1, figs. 8,13 198 1 i-lilldeodll s parvlis (kozur & pjatakov a , 1975) matsuda, p. 91 -93, pi. 5, figs. 1,?2 1990a n il/deodll s parvlls (kozur & pjatakoya , 1976), morphotype 1 kozur , p. 400 1995 n il/deodlls latidel/ta tus (kozur, mostler & rai-jl m i-y azd), pars metcalfe, on ly the spcci men on pi. 2, fig. 7 derivation of na me: accord ing to the erect denti ­ c1es of the blade behind the cusp. holot.ype: the specimen on pi. ii , fig. 6, rep. -no. 123254 , refigured from wang (j 994, pi. i , fig. 1). loclis tyi)icll s : meishan section (sout h chin a) , zhongxin dadui quarry. stratulll typicum: upper pan of boundary bed 2, sample 882-4 ( 12 -16 em above the base of boundary bcd 2), h. par i/us zone of lowermost triassic. material: severa l hundred specimcns. diagnosis: hil/deodus parvlis with slender, sma ll , e rec t denti c les, al l nea rl y of the same s ize. t he com­ mon ly hi gh posterio r part of the blade is steep ly inc li ned and undent ieulated, but in the upper part o f this smooth portion a small denticle is commonly present in adult rorm s. descripl.ion: the pa e lement is small , with a very large, slender cusp, more than twice as long as the ro l ~ lowing dcllti c les . t he cup is wide, but not thi ckened. the b lade is s hort , hi gh, in adults wi th four to seven e rec t, small , s lender denticles of equal leng th . the uppcr edge of the blade is horizontal , straight or nea rl y so. the poste rior pan o f the blade is (except for a small denticle in adults) smooth, commonly high and steeply dipping. for the ram ifolm clements see at h. parvl/s. occurrence: world-wide guide-form of the lower­ most triassic. h.cmarks: the meishan section is proposed as the gssp fo r the base of the triassic that is defined by the first appea rance o r h. parvus in the upper half of bounda ry bcd 2 . for th is reason, th e holot ype of h. parv//s cr a'ius n.subsp. is chosen from the upper half o f boundary beel 2 or that section. specimens of this sub­ speci es from ot her part of the world demonstra te the wide distribution or this taxon. 97 in nil/deodlls parvlis parvlls (kozur & pjata­ kov a, 1976), the upper profile of the blade behind the large cusp is slightly incl ined. the steeply inc lined pos­ te rior pan of the blade bears 2-3 slllall denticles. both f'ofms are connected by transitional forms in the lower palt or the ir ranges and have been discriminated as two morphotypes of h. pan'us by kozur ( 1990a), mor­ photype 1 being h. parvlfs cree/lis. however, the differ­ ences are la rge enough to dist ingui sh two subspec ies . acco rding to prof. wang (na njin g, pe l's. comm.) , both morphotypes have a sli ghtly different range. in our mate rial, di ffe rent occurrences a re ra the r fac ies-con­ trolled. the rich fauna of th e lowe rmost t ri ass ic of sicily consists exclusively of h . parv{(s cr ccfl/s, mostly juvenile forms. they have been derived from anoxi c to dysaerobic beds deposited under grea te r wate r depth. as this fa una con sisls o f numerou s spec ime ns in a monospeeific faun a, h. parvlls erecllls could seemingly li ve near the ecologi c tolerance bounda ry fo r con­ odont s. h. parvtts parvlts and an y o lhe r conodont species could noi live in this fac ies. i-i. parvus crec/ll s is a lso present in shall ow-water deposit s of the southern alps and in pelagic red, bioturbate c lays and marls in transcaucasia. it also occurs in pe lagie gray beds with ammonoids and/or gondolclli d conodonts in iran , soulh chin a, in peri-g ondwan a kashmi r and in greenland. t hi s universal dist ribution makes the first appearance of h. parvus ereclus an excellent markcr for the base of the triass ic. this is in agreeme nt with the opinion of wang (1994) to usc the first appearance o f h. parv"s morphotype i for the definition of the base of triass ic. its fore runner, connected by trans itional form s in strati ­ graphic sequence in several sec tions, is h . lar idelllallis pracparvlls n.subsp. it is distinguished by a somewhat larger pa clement with shonei' and broader cusp and by the beginning of the in ward curved part o f' the sb e le­ ment in front of the cusp. hindeodus c1wllgxillgellsis wang , 1995 (pi. v, figs. [,2) 1994 '-lindeodlls n. sp. wang, pi. i , fi g. [0 1994 "lindeodlls jll/fel/sis (sweet , 1973) wang, pi. i , fig. 11 1995b hilldeodus c/tallgxingclisis sp.nov. wang , p. 149-150, pi. 2, fi gs. 1418 description: the pa element has a lanceolate, deep ly excava ted cu p. the free b lade bears a very broad and long, e rect cusp , wh ich is approxim ate ly three times longer than the following small denticles on the blade. one to fou r (most ly one or two) denticl es behind the cusp have discrete tips. the tips o f the fo l­ lowi ng dent ic lcs are fused to a strai ght o r some what wavy ridge that is horizontal or nearly horizonta l. the poste ri or end of the fu sed part dips very steeply, often verti cally and on ly this part may be convex. the fol ­ low in g posterior third of the bl ade bears two to four d isc rete, broad, but low denticles. the upper pro file of 9' ihis part is gently inclined backwards. ramiform cle­ ments cannol be assigned precisely to this species because it always occurs together with several other hindeodus species. occurrence: hindeod/ls challgxillgensis \vang is restricted 10 the uppermost part of the changxingian and the lowermost 4 ern of the triassic part of the boundary beds at mcishan (south china). remarks: h. cf1allg.-ringcnsis was first figured as hilldeodlls n.sp. by wang (1994), but not described. the description was published in wang (l995b). he restricted this species to forms with a long fused, hori­ zonta l pan of the blade and only one free denticle between the cusp and the fused part of the blade. ponns with three to four free dcnticlcs behind the cllp and a short, rising backwards fused part of the blade, were assigned to ii. jllljcl/sis (sweet) by wang (1994, 1995b). however, thcse forms arc closely rclated to the type ii. cilangxillgensis in having a very large cusp, rather few free denticles between the cusp and the fused part of the blade, and an often long, gently backward dipping posterior part of the blade. they arc therefore assigned to ii. c/j({ligxillgellsis. i-lilldeodlls jllifei/sis (sweet , 1973) has a shorter cusp, more free denticlcs between the cusp and the por­ tion with fused denticles (five to seven, in advanced forms four) that is always a convex hump, and the por­ tion with free denticles behind the fused part is consid­ erably steeper dipping and mostly shoncr. in hilldeodlls al/lldael/sis kozur & mostler, 1995 the fused part is also straight, but distinctly inclined backwards. th e posterior part of the blade behind the portion with fused denticles is stro ngly inclined, more or less vert ical close to the posterior end . hilldcadlls pasiparvlis kozur, 1990 (pi. 11, figs. 9, 10) 1958 spa/llogl/o/hodlls cf. 111 ill 11/11.1 (ellison) huckriede, p. 162, pi. 10, fig. 8 1975 allchigl/a/llodlls parviis kozur & pjatako­ v a n.sp., pars kozur, p. 7-9, pi. i, figs. 19, 20, non! figs. 17,21 -23 1976 anchignafl/odl/s parv/./s n.sp., pars kozur & p.jatakova, p . 123-125, figs. ie , d, non! rigs. 1 a, b, e, g, h '11981 hi/ldeodus lliilllltlls (e llison , 1941), pars matsuda , p. 78-91, only pi. 3, fig. 10 1990a hil/deodils pas/pan'lis n.sp. kozur, p. 400 1995 i-i illdeodlls jllltc>lisis (teichert, kummel & sweet) metcalfe, pi. 2, fig. 10 1995 !-lil/deodils la/idel//a/lls (kozur, mostler & rahimi-y azd), pars metcalf'e, pi. 2, fig. 8 diagnosis: the pa clemcnt is small and arched. 11 has commonly a large cusp and six to seven, rarely geologia croatica 49/1 more, large, high ly fused denticl es with strongly diverging inclination. one or two, rarely three or four small dent icles may be present on the anterior edgc of the cusp, forming a reduced anterior blade. the denti­ cles are largest in the mid-length of the blade or some­ what behind it. this size distr ibulion together with the strongly diverging inclination of the denticles results in an distinctly arched upper profil e of the pa element. the cup is large, but not thickened. the m clement dis­ plays a distinct, denticulated posterior bar, very differ­ ent from all other hiljdeodus spccies. the other rami­ form elements are not yet exactly assignable to i-/, post­ parvlis, but except the sc element they may be all com­ parable to those of i-i. parvlfs. occurrence: upper oplliccras ribericlll11 ammonoid zone of the lowermost triassic. the species first occurs in the i. isarcica zone, but its main occurrence lies above this zone. remarks: metcalfe (1995) assigned a pa cle­ ment of ii. posrparvlfs to the characteristic changxin­ gian guide form /-i. jll/j"el/sis (sweet). a part or h. lalidclllaflls sensu metcalfe (1995) belongs also to h. poslparvus (op.cit., pi. 2, fig. 8). other specimens of i-i. la/iden/a/lls sensu metcalfe (1995) belong to !-i. parvl/s (op.cit., pi. 2, fig. 7) or !-i. cf. fypicalis (op.cit., pi. 2, figs. 6, 9). the latter forms are, as h. parvus, typ­ ical conodonts of the lowe rmost triassic. formerly, they were assigned mostly (0 h. typicalis. but arc dis­ tinguished from this species by the smaller pa clement and irregular denticies of the blade that are often wider separated. the clisp is slender and moderately long. by their slender cusp and irregular denticlcs they arc also distinguished from !-i. latidcllfatus praeparvl/s. these forms will bc dcseribed as independent taxa in a sepa­ rate paper because their appa ratu ses arc not yet well known. as the figured specimens of the changxingi an clarkina cilangxingensis (wang & wang) by met­ calfe (1995) belong a ll to the triassic clarkina cal1/lata (clark) sensu stricto and closely relatcd forms, the entire fauna is typical for the i. isarcica zone and the following h. posfparvus fauna (or zone) and not a mixed fauna of griesbachian age with reworked permi· an elements as assumed by metcalf'e (1995). h. postparvlfs kozur evolved from h. parl'lfs par "".1 (kozur & pjatakova) (~f-i. par,,"s, mor­ photype 2) by separation of the posterior dentieles of the pa clement in size and inclination from the erect anterior denticies. moreover, in fl. i}(iitiis parvlis only lhe upper profile of the postcrior third of the blade is arched, the upper profile of lhe anterior portion of the blade bcing horizontal or inclined slightly in the poste­ rior direction. an otiler difference is the devclopment of a denliculaled poslerior bar in the m clement. most of the ramiform elements of h. poslpaj"l'1i5; cannot be correctly assigned to this species because h. postparvl/s always occurs together with other liindeo­ dl/s species. only the m element with a denticulated korur: '1l1c conodonts 1/illd('odiis. fsarcicc/fa ;lnd si1'(!('lofrilldeodlls ... posterior bar can be easily recognizcd because this fea­ ture is missing in all other hindeadus species. only very advanced small pa elements of h. parvus from the h. postparvus zone may have an apparatus, in which the m clement has a dent iculated posterior bar. as the development of a posterior bar in the m clement is an unique and easi ly recognizable feature of the hindeo­ dus apparatus, there may be also other explanations for the occurrence of this feature in very advanced h. parvl/s apparatuses. either the intraspecific variabiliy of the pa element of h. postparvlfs is high, and parts of the pa clements cannot be distinguished from those of h. parvl/.\" or thc development of a posterior bar in the m clement begins earlier then the changes of the pa cle­ ment and apparatuses with h. parvus pa element and ' -i. posfparv/ls m element represent transitional forms between both species . in one samp le from transcaucasia that yielded only h. posrparvils and h. parvlfs al/faodel1tallls, typica l but broken ramifonn e lement s of hindeodus occur. only the sc element is rather well preserved and corre­ sponds to the sc element figured by matsuda (1981, pl. 3, rig. 10). it disp lays an inward curved, short and high an terior bar with one very big terminal denticle. the c usp is moderately large, but not larger than the den ticle on the ante ri or bar. the posterior bar displays three to four denticles behind the cusp and three large denticles in the posterior part. this sc e lement is more advanced than that of h. parvus, but it may belong both to h. parvlfs (flllerodentatus or to h. posfparvlis. hilldeodus sosioensis i1.sp. (pl. iv, figs. 2-4) derivation of name: according to its occurrcnce in the sosio valley, western sicily. holotype: thc specimen on pi. iv , fig. 2; rep. -no. 412-94/v1-14. locus typicus: 350 m south of pi etra dei saracini, 50 m east of the road. stratum typicum: floated block of turbiditic grad­ ed calcarenite, earliest triassic. material: 6 specimcns. diagnosis: the pa clemen t has a short , but distinct anterior bar and large denticles on the posterior bar, one of them being as large as the prominent cusp. the sb c lemen t is short and high, but between the cusp and the inward curved part of the anterio r bar a short, denticu­ lated, horizontal part of the anterior bar is present. description: the pa element is distinctly arched. it has a short anterior bar that bears two small , erect denti­ cles. the cusp is large, nearly erect to inclined slightly backwards. the posterior bar bears around seven large denticlcs that are inclined slightly backwards. the incli­ nation docs not increase significantly towards the poste­ rior end . the size of the denticles is variable, the sec­ ond one is as long and broad as the cusp. the cup is moderately wide, not thickened. 99 the pb e lement is short and relatively high. its ante­ rior bar bears three denticles, two of them arc rather large. the cusp is large and inclined backwards. the posterior bar bears seven moderately inclined denticles of different size, the largest occurring in the posterior half of the bar. the lower side of the bar is sl ightly inverted, but an elongated basal cavity and a narrow basal furrow are present. the sb element is short and high. the antcrior bar is strongly inward-curved, but its po sterior part is hori­ zon tal and bears four small denticles. the inward curved part bears seven denticlcs; one or two denticles at its anterior cnd are very large. the posterior bar has seven denticles of different size, but behind the cusp they are smaller and at the posterior end one or two large denticles are present. the lower side of the bar is strongly inverted. occurrence: lowermost triassic of sicily. /-lindea­ dus sosioclisis n.sp. has been deri ved from a floated block of graded calcarenites, with h. cf. rypicalis (pi. iv , fig. i) and ellisollia trollsito kozur & most­ ler. changxingian c/arkij/a species are missing. in the exposcd part, all scythian calcarenites with hindeo­ dlls belong to the isarcicella isarcica zone. h. cf. typi­ calis occurs from the h. parvus zone to the 1-1. posi­ parvlfs fauna (or zone) immediately above the i. isarci­ ea zone. remarks: the pa element is only similar to that of f-iilldeodlis postparvlis (kozur , 1990) which also has an arched pa element with a largc cusp and large denti­ eles on the blade. however, in h. posrparvus the incli­ nation of the denticles is more divergent and no denticle behind the cusp is as long as the cusp. sample ks 2 contains all the ramiform clements of hindcadus , except the sa element that is always rare in hilldeodlls. however, only the sb element and the pb element are different from those in hindeodus cf. typi­ calis, the second hindeodlls species that is represented by pa c lements in this sample. for this reason, the sc and m element of ' -/. sosioensis arc either identical with those of h. cr. typicalis or not present in sample pk 2. sb and pb elements disp lay some features of h. typi­ calis (sweet , 1973) and some feat ures of h. pm· viis (kozur & pjatakova , 1976), but are different from those elemcnts in both species. the sb element is as high and short as in h. parvlfs. however, the posteri­ or part of the anterior bar is not inward-curved, hori­ zontal and bears up to four small denticles as in i-i. typi­ calis. the pb element of h. fypicalis is longer, above all, the anterior bar is considerably longer, but lower relative to its length. in h. parv[{s, the anterior bar of the pb e lement is shorter (only one denticl e) and the ent ire unit is higher. genus lsarcicella kozur, 1975 type species: spathognathodus isareiells huck­ riede, 1958 100 occurrence: uppermost changxingian and lower two zones of the triassic, but common only in the isar­ cicella isarcica zone. remarks: sec al i-lindeodlls rexroad & cur­ nisi-i, 1964. isarcicella isarcica (huckriede) (pi. y, figs. 6, 9) 1958 ,s'pathop,liafhodus isarciclis n.sp. huck­ riede, p. 162, pi. 10, figs. 6,7 1975 isarcicello isarciciis (huckriede) kozur, p. 12 198j isarcicella isw'cica (i-juckriede) matsu­ da, p. 93-94, textfig. 5, pi. 5, figs. 4-7 1981 isarcicello 'lsi'. matsuda, p. 94-95, pi. 5, fig.8 1989 isarcicello staeschei dai & zhang (sp.nov.) dai & zhang, p. 430-431, pi. 45, figs. 16, 17; pi. 46, figs. 4 -7,11 -13 ,18,19; pi. 53, figs. 13, 14 1989 isarcicella triallglliara da1 & zhang (sp.nov.) dai & zhang, p. 431, pi. 46, figs. 8-10, 2j occurrence: very rare in the upper h. parvlfs zone (only i. isarcica staeschei da1 & zhang). common in the i. isarcica zone. north america and tethys, including the peri-gondwana tethys margin. until now unobserved in greenland. remarks: isarcicella isarcica evolved from i.? turgido (kozur, mostler & rahimiy azd, 1975) through i. isarcica sfaeschei oaf & zhang, 1989 as transitional forms. the most primitive repre­ selllatives of isarcicella s.str. display only one denticle attached to a side of the thickened blade or the blade is bifurcated. such forms very rarely occur in the h. parvlis zone of the southern alps (one specimen reporled by perri, 1991) and of kashmir (one speci­ mcn from the if. paj'\'us zone of the upper otoceras woodwardi zone, reported by matsuda, 1981 as isarcicella? sp.). as these form s arc ex trcmely rare (only one specimen of each type is known so far), it cannot bc determined whether they arc independen t taxa, subspecics of i. isarcica or pathological forms of i.? rurgida. forms with onc or two denticles on one side of the cup dominate throughout the i. ism'cica zone, but forms wit h denticlcs or a short secondary blade on both sides of the cup also occur there. the holotype of i. isarcica belongs to these latter forms. dai & zhang (1989) separated specimens with denticles only on one side as a diffcrent spec ies. unfortunately, they have chosen a form with two dentieles on one sidc of the cup as holotype. such forms occur exclusively in thc i. isar­ cico zone, as do forms with dent ides on both sides of the cup. only specimens with one denticle on one side of the cup havc a different range. 1t is probably that only these forms represent a different taxon and the gcologll croalica 49/1 separation proposed by dai & zh ang (1989) is an arbitrary one. however, it is possible to usc!. sfaeschei as an indcpendent subspecies!. isarcica staeschei da1 & zhang (pi. y, fig. 6). isarcicella triangularis dai & zhang, 1989, wilh triangular platform, is only a morphotype of i. fsarcico with th e same range as the other morphotypes . 1l is regarded as junior synonym of i. isarcica. isarcicella? turgida (kozur, mostler & rahimi-y azd, 1975) (pi. y, figs. 7, 8) 1975 ancilignarliodlls turgidlls n.sp. kozur , mostler & r ai-limi-yi\ zd, p. 5-6, pi. 7, figs. ii , 12 1989 anchignathodus decrescens dai & zhang (sp.nov.) dai & zhang, p. 428, pi. 39, figs. 11-13 1993 isarcicella tllrgida (kozur, mostler & raj-limiyazd) gullo & kozur, figs. 2/7-9 71995 hindcodlls latidentatlls (kozur , mostler & rahimi-yazd) zhang el ai., pi. 2, fig. 12 1995 hilldeodus pm' vas isarcicella transition 7 metcalfe, pi. i, figs. 12, 13 1996 hindcodus {jorvlis, pars mel, p. 146 occurrence: lowermost triassic h. parvlfs and i. isarcica zones. i. c1'. turg ida occurs in the uppermost changxingian. remarks: as shown 011 pi. v, fig. 7, the inner part of the cup in 1.7 rurgida is thickcncd to form a platfoml, as in isarcicella isarcica. this is the main difference to h. parvl/s, but addi tionally 1.7 {urgido is larger, dis­ plays more denticlcs, and primitivc forms from the uppermost changxingian (1.7 c1'. turgida, probably a separate taxon) display a low blade. unlike i. isarcica, the platform of i.? turgida does not bear a denticle or a secondary blade on one or both sides. ttoweve r, as these forms already exhibi t one of the isarcicella fea­ tures, they have been assigned to isal'cicclla by gul­ lo & kozur (1993). i. ? tllrgida was regarded until now as a transitional form between h. parvlf.'; and!. isarcica. however, 1.7 cr. furgida (distinguished by its low bladc from typical 1.7 tllrgida) which is the immediate ancestor of typi cal i.? fllrgida, first occurs in the uppermost changxingian, bcforc the first appearance of h. parvl/s. the specimen figured by zhang el al. (1995, pi. 2, fig. 12, re-fig­ ured by yjn & zhang, 1996, pi. u.8, fig. 11 , and by zhang el ai. , 1996, fig. 5.3) as i-i. lotidentolils from bed 25 of meishan, perhaps belongs to i.? c1'. tlfrgida but no upper view was figured , and therefore it cannot be decided whether the cup is thickened. if the cup is not thickened , this specimen would be either a f-l. lati­ denafus praeparvlis with unusual large cusp (i n this case the original determination would be correct) or kolllr: 'ille conodollls ffilldn)(llls, is(lrciall(l and sli'l'cloililulcl.j{llls ... ralher a new species. the ve ly large, broad clisp and the low blade of this speci men are c harac terist ic for i. c f. f/lrgida, but also for somc specimens of ii, /a/idelifatus praepan'l/s. mel (1996) assigned this specime n 10 h . (jor\'lis because of its very big clisp, but /-i. parvlis dis­ plays a hi gh blade and not such a broad cusp as in this specimen. ii. porvlfs and 1.7 f/lrgida first appear in the meishan sec tion in beds 27 c. a deri vation o r i .? fiirgi­ da from i-i . parvus can be the refore excl uded, the more as /-i. posfparv//s evolved from h. parvlls. orchard ( 1996) assig ned h. latidentgllls sensu z ii ang et a l. (1995, pi. 2, fig. 12) to isarcicella arr. parva, but in a wr iltc n communicat ion he s tated that thi s specimen be longs neithe r to h. latidellla/lls nor to "/. " parva. allchigllathodlls deerescells dai & zhang, 1989 is a junior synonym of 1. 7 flfrgida (kozur, most­ ler & rahim i· yazd, 1975). also this spec ics is characteri zed by a thickened in ne r part of the cup and by a prominen t cusp that is more than twice as long as the following dent iclcs. the f igured specime ns arc somewhat smaller and have fewer denticles than adult 1.7 flfrgida. they arc seemi ngly juveni le specimens. isarcicella isqi'cica (h uckriede, 1958) displays denticles on the cup. most primitive representat ives of i. isarcica sraesciiei dai & z hang ( 1989) bear only o ll e de nti c le 011 one s ide of' the cup. they arc transiti ­ onal forms bctween /. ? filrgida and i . isardca. isardcelfa? prisca kozur, 1995a from the upper­ most c hangx ingian displays a dent icu lation of the blade as in /-i . (arideljfoflis morphotype 2. the c usp is distinc t­ ly sm alter than in i, ? /urgida. isarcicella? prism kozur, 1995a (pi. i v, rig. 9) 1991 nil/deodl/s typicali" (s weet), pars· perri, p. 40,42, pi. 3, figs. i , 3, 4 1995a isarcicella? prisca n.sp.· kozur. p. 168, pi. 6, figs. 3,4 description: th e pa c le me nt is ra the r sm all and bears s ix \0 nine s li ghtl y backward inclined dent icles that arc largest in the posteri or half of the blade. the cusp is considerably broader and somewhat to distinctly larger than the fo llowing denticics, the inne r part of the c up is d is tinctly thickened, but the outer, un thic ke ned part is ra ther broad. occurrence: upper c hangxingian tesero oolite of southe rn alps. uppennost dorashami an of transca u­ cas ia (onl y broken specimens) and uppe rmost chan g­ xingian of south china. remarks : the dentie ulation of the blade and the s ize of the c usp corresponds to hindeodus lalidelltatlfs (kozur, mostler & ra ht mi·yaz d, 1975). i.? prisca n, sp. is d istinguished from ii. latidellfallfs by the dist inc t thickenin g of the inner pan of the cup, typical for all i sarc icella spec ies, bu t the unthi ekencd part of the clip is s tili rather broad. isarcicella? tllrgida (kozur , most ler & ra· 101 him!· y azd, 1975) from th e lowerm ost triass ic dis· plays a more prominent c usp thai is 1110re than twice as long as the rollowing de nt ic les. t he thickened part of its clip is wider than in i.? prisca, the most primiti ve isarcicella species . genus sweelohilldeodus n.gen . type species: sweelohilldeodlls bidemall/s n. gen. n.sp. derivation of name: in honour of prof. w.e. sweet, columbus, [or his outstanding contribution to upper pe rm ian-lowe r triass ic h indcodus taxonomy and in gratitude fo r his help with my conodont studies, diagnosis: the cup is large, circular to subcircular. the blade is very short, son1ew hat thickened on the cup, with a large, erect cusp that is [oiiowed by one or two large separated de nt icles. occurrence: isarcicella isarcica zone (lowe r scythian) of wes tern sicily. assigned species: swcetohil1deodlls bie/clllallts n.gel1. n.sp. sweetohilldeodlls iridcjlfclfils n.sp. remarks: o nly the pa e lement of sweetohindeod/./s is known. the short blade wi th two or three large sepa­ rated den ticies (i ncluding the c usp) clearly dis tinguish­ es the pa clcmen t of sweelohilldeodlls from that of its ances tor, hilldeodlls rexroad & furn is h, 1964. sweeloltilldeodus bidelltallis n.sp. (pi. v, r igs. 3, 4) derivation of name: accord ing to the presence or only two large dcnticles. hololypc: the specimen figured on pi. v. fig. 4; rep. · no. ko 12·1 1·9 i/1x·2. lochs typiclis: lowe r triassic section 350 m sollth of pietra dei saracin i, sosio valley, wes tern sicily (see fig. 4). stratum t ypicum: sam ple ko 12 a, uppermost 5 cm of a g raded calcarenite of the 2 m thick lower calei­ turbidites above the lowerm ost t riassic shales. isarci~ cella isarcica zone of lower scythian. material: 7 specimens. diagnos is: t he very s hort bl ade bears two de illi ­ d es, a slender, large ellsp and a ve ry broad dent icle, far broader than and as long as the cusp. description: the cup is large, subeircular and at it s lower s ide is deeply excavated. the very short b lade bears only two e rec t denticles. one of the m, the cllsp, is long and s le nder; it is s itua ted o n the free part of the blade. the o ther one is very broad, laterall y compressed and subeonieal. in the direc tion of the blade, the base of th is denticle is only a li ttle shorter than the c up. both dent icles may be finely striated. 102 o 60 km ~ a.' • 1y b • "0 2( " ~" ,~ 0 500 m <5'", "0 n t palazzo adriano "'1> .,~ '0 c :-. ++ + fig . 4 location of ihe investigated outcrops in western sicily , [ial y. legend: blac k) predominant ly wordian sasio limes tone klippes (s lope facies with fu sulin id -bearing shall ow-w at er limestone bloc ks): a) ru pc d i san caloge ro and pi cu'a dei sarac ini , three adjacent isolated lirncslonc blocks, no longer accessi bl e; b) rupc del passo <ii burgio: piclra eli salomone; stars) permian base o f slope facies and t ri ass ic cover; i) several outc rops ca. 350 m soulh o f pi clra dei sarac ini covering the road ian ( lowermost middle [>cnnian. guadalupian series) 10 jul ian (midd le carn ian) i nterval; 2) outcrops c;t 100 ill ssw of rupc del passo el i bur­ g io. main ly lowcr cathedral ian (c isumlian, early permi • .ul) tur­ bidites wcll cx posed west of a small road , a long the road lower cathc(\r:llian tu rbidi tes (partly exposed) and tectonicall y adjacent cha ngx ingian red marls and thi ck calcaren ites, no longer ex posed, but small floated blocks of calcarenit es still present. crosses) t orrcnt e san calogero sec tion, permian deep bas in facies and parts of the triassic cover. occurrence: i. isarcica zone of the type locality. l~emarks: sweeloh illdeodlfs fridel/laws n. sp. has two dcllt ic lcs on the blade behind the cusp that are d is­ tinc tly shorte r then the clisp. sweelohimleodlls iridenlatlls n.sp. (pi. v , fig. 5) derivation of name: accord ing to the presence of th ree dentie les (includ ing the cusp). holotypc: the specim en fi gured on pi. v, fig. 5; rep.no. ko 12 11 9 1/ix1. loclls typicus: lower triassic section 350 m south o f pietnl dei saracini , sosio valley, western sici ly. stratum typicum: sample ko j 2 c, lower mic ro­ cong lomcratic calcarenite of the upper bed of the 2 iii geologia crq:l1ica 49/1 thi ck calciturbidites above the lowe rmost triass ic shales. lsarcicella isarcica zone of lower scyth ian. material: 2 specimens. diagnosis: the cup is c irc ul ar. the blade is vcry shon and bears a large e recl cusp and two di s tinc tl y shorter, but also large , separat ed dentic les. description: the cup is large, circular and its lower side is deeply excavated. the short blade bea rs on its free anterior part a large, c rcct, slende r c usp. on the cup, the blade bears two large, separated denticles that are distinct ly shorter than the cusp. the poste rior one is s lightly inc lined backward. its base is as broad as the base orthe cusp. all dcnticles are slightly stria ted . occurrence: i. isarcica zone o f the ty pe loca lity and o f soulh china. remarks: this species is a transit ional form to hill­ deodlls, in which the blade is longer and bears even in ju venile forms at least four dcnt ic les. the clip o f fl il/ ­ deodus is lanceolatc or oval. 5\veelollilldeodi/s bidema­ ills n.sp. has only one very large denti c le on the blade above the cup that is as long as the clisp. acknowledgement the investigations for this paper were sponsored by the deutsche forsehungsgcmeinschafl. i am very gra te­ ful for this important he lp . i waflttly th an k prof. w.e. sweet, columbus , and hi s wife, for the hosp italit y and ihe opportunity to study the conodont mate ria l from greenland, kashmir and julfa. pro f. b.f. gl en ister, iowa c ity, read the man usc ript c ri tica ll y; i am vcry grate ful for this he lp. s. referenc es dai , j. & zhang , j. (1989): conodonts.in: siudy on the pe rmian -triass ic biostrati graphy and even t strati graphy of nonhern si chu an and so uth e rn shaanxi. geol. mem., 2/9, 428-435, be ijing. ellison, s. ( 194 1) : rev is io n of the penn sy lva nian conodonts.1. paleonl. , 15, 107143. gullo, m. & kozur, 1-1. ( 1993): firs t evidence of scythian conodonts in s icily.n. jb. geo!. paniont. mh., 1993/8,477-488. huckriede, r. (1958): die conodonlen de l' meditcr­ ranen trias und ihr s tratigraphischer wert. palaont. z. , 32/3-4, 141 -175. jl n, y. , s hen, s. , zh u, z. , mel , s. & wang, w. (1996): the sejong section , candidate of the globa l stratotype section and point of the pe rmian-triassic boundary.in: yin, h. (cd. ): the palaeozoic-meso­ zoic boundary. candidates of g lobal s trat otype sec­ lion and point of th e permian -triass ic bo undary. 127-137, wuhan, china unive rsity o f geosc iences press. kozur: 111c conodonts ifilldcodlls. {sareia lla and sweeroliindeodu,l" ... kozur, i-i. ( 1975): beitrage zur conodontenfauna des penn.geol.-palaon!. mit!. innsbruck, 5/4, 1-44. kozur, i-l, (j 977a): die fauneniinderungen nahe der permrrriasund trias/1ura-grenze und ihre mogli­ chen ursac hcn . ted i: die lage del' perm/trias­ gfenze und die anderung del' faunen und floren im pefmrrfias-grenzbereich.freiberger forsch.-h. , c 326,73-86. kozur, [-i. (1977b): revision der conodontengattung anchignat!jodus und ihrer typusart. zeitschr. geo!. wiss.,5/9,1113 11 27 . kozur, h. (1985): biostrat igraphi c eval uation of the upper paleozoic conodonts , ost racods, and holo­ thurian sc lerites of the biikk mts., part ii: upper paleozoic ostracods.acta geo l. hungar., 28/3 -4, 225-256. kozur, h. (1989) : the permian-triassic boundary in marine and con tinental sedi ments. zbl. geo!. pal'iont., 11/12 (1988), 1245-1 277. kozur, h. (l 990a): si gn ificance of evcnts in con ­ odont evolut ion for the permian and triassic stratig­ raphy.com. forseh. -ins!. scnckenberg, 11 7, 409469. kozur , h. (l990b): the taxonom y of the gondolellid conodonts in th e permian and triass ic.com. forsch. -ins!. senckcnbcrg, 11 7,409-469. kozur, h. ( 1991 a): perm ian deepwater ostracods from sic il y (italy). part 1: taxonomy. gool. pawont. mit l. tnnsbruck, sondcrbd ., 3, 1-24. kozur , [-i. (1991b): permi an deep-water ostracods [rom sicily (ital y). part 2: biofacial evaluation and remarks to the silurian to triassic paleopsychros­ pheric ostracods.geo!. palaonl. mitl. innsbruck, sonderbd., 3, 25-38, innsbruck. kozur, h. (1994a): permian pelagic and shallow­ water conodont zonatiol1.permophiles, 24, 16-20. kozu r, h. (1 994b) : the pennian{rriassic boundary and possible ca uses of the fau nal change near the prr boundary.permophiles, 24, 51-54. kozur, h. ( 1995a) : perm ian conodont zonation and its importance for the permian st ratigraph ic standard scale. geol. -pahio nt. mitt. tnnsbruck , 20 , fest­ schrift zli m 60 . gebllrlstag von helfri ed mostl er, 165-205 . kozur, h. (1995b) : some remarks to the conodonts hilldeodus and isarcicella in the latest permi an and earliest triassic.palaeoworld, 6, 64-77, nanjing. kozur, i-i. , leven, e. ja. lozovskij , v.r. & pjata kov a, m.v. (1978): raschlenenie po kon­ odonta m pogranichnych sloev penni i triasa zakavkazja.bjul. moip, otd. geol. , 1978/5, 15-24, moskva. 103 kozur,i-j. & mostler, h. ( l995 ): guadalupian (middle permian) conodonts of sponge-bearing limestones from the margins of the delaware basin, west texas. geol. croat., 48/2,107 -128. kozur, r. , mostler, h. & rahiml-y azd, a. (1975): beitrage zur mikropahionto log ie permotri­ adischer schichtfolgen. teil it: neue conodonten aus dem oberperm und der basalen tri as von nord­ und zentraliran. geol.-pahiont. mitt. inn sbruck, 5/3, 1-23. kozur , i-i. & pjatakov a, m. ( 1976): die con­ odontenart anchignathodlfs parvlis n. sp ., ein e wichtige leitform del' basal en trias.proc. koninkl. nederl. akad. wetensch. , series b, 79/2, 123-128, amsterdam. kozur, h.w. , ramovs, a., wang c.-y . & zakharov, yu. (1996): thc importance of hin ­ deodus par viis (conodonta) for the defini tion of the permi an-triass ic boundary and evaluation of the proposed sections for a global st ratotypc scct ion and point (gssp) for the base of the triassic.geologi­ ja, 37/38, 173-2 13, ljubljana. krystyn, l. & orchard, m.l (1996): lower­ most triassic ammonoid and conodont biostratigra­ phy of spiti, india. alberti ana, 17, 10-21, utrecht. matsuda , t. (1981): earl y triass ic conodon ts from kashm ir, india. part i: hilldeodus and isarcicella .­ j. geosci., osaka city univ., 24/3, 75-108, osaka. mel, s. (1996): restudy of conodonts from the penn i­ an-triassic bound ary beds at selong and meishan and the natural perm ian-triassic boundary.in: wang, h. & wang, x. (eds.): centennial memo­ ria l vol ume of prof. sun yuns hu: palaeontology and stratigraphy. 141 -148, beijing, china universi­ ty of geosciences press. metcalfe, i. (1995): mixed permo-triass ic bound­ ary conodont assemb lages from gua sei and kam ­ pon g gua, pahang, peninsul ar malaysia.com. forsch.-[nst. senckenberg, 182,487-495. nestell, m.k. & ward law, b.r. (1987): upper pe rmian conodonts from hydra, grcccc.j. p alc­ on!., 61/4, 758-772. newell, n.d. ( 1994): is there a precise permian -tri­ assic boundary?permophil es, 24 , 46-48. orchard, mj. ( 1994) : conodonts from o/accras beds: are they permian'?permophiles, 24, 49-5 1. orchard, m.j. (1996): conodont fauna from the perm ian triassic boundary: observations and reser­ vat ions.permophiles, 28, 36-3 9. orchard, mj., nassichuk , w.w. & ruj , l. ( 1994): conodonts from the lower gri esbachian otoceras latilobatulli bed of selong, tibet and the position of the pennian -triassic boundary. canadi­ an soc. petrol. geol., mem. 17,823-843. 104 paull. r.k. & paull, r.a. (1994) : i-lilldeodlls parv/ls proposed index fossil for the permian-tri­ ass ic boundary. lethaia, 27, 272-272. perri, m.e. (1991): conoelonl bioslraligraphy of ihe \verfcll formation (lower triassic), southern alps, llaly. boll. soc. paleon!. i!. , 30/1,23-46. perri, m.e. & andraghetti , m. (1987): penni­ an-triassic boundary and early triassic conodonts from the southern alps, 11aly. riv. it. palcont. slra!., 93/3, 29 1-328 . rexroad, e. b. (1 957): conodonls from ihe chesler series in the type area of southwestern illinois.illi­ nois stale geological survey repo rt of inves ti ga­ lions, 199, 1-43, urbana. rexroa d, e.b. & furnisit, w.m . ( 1964) : con­ odonts from the pella formation (mississ ippian), south -central lowa. journ al of paleontology, 38, 667-676. schonlau b, h.p. (1991): the permian-triassic of the gartnerkogcl-l core (carnic alps, austria): conodont biostratigraphy.j\bh. geo!. b. -a ., 45, 79-98 . s heng,.t, chen, e., wang y.-g., rui, l. , liao , z.-t., bando, y., lsi-ii , k. , nakaza wa, k. & nakamura, k. (1 984) : permian-triassic bound ­ ary in middle and eas tern tethys.jollfll. fae. sci. , hokkaido univ., sci'. 4, 21/1, 133-181 , sapporo. staesci-ie, u. (1964) : conodonlen aus dcm skylh von siiell iro l. n. ib. geol. pat;ion!., abh. , 119/3, 247-306. sweet, w.e. ( 1970a): pe rmian anel triassic con ­ odonts rrom a section at guryul ravine, vihi dis­ trict, kashmir. univ . kansas pal eonl contrib., paper 49,1 -10. sweet, w. e. (1970b): uppcrmosl permian anel low­ cr triassic conodont s of the salt rangc and trans­ indus ranges, west pakistan .in: kummel, b. & teichert, e. (cds.): siraligraphic boundary prob­ lems: permian and triassic or west pakistan. univ. kansas, dcp!. geol., special publ. , 4, 207-275. sweet, w.e. (1976): conoelonls from ihe pe rmian­ triassic boundary bcds at kap stosch, east green­ land.medd . gronland, 197,51-54, kpbcnhavn. sweet , \v.c. (1977): genus hindedolfs , genus isarci­ cel /a. in: ziegler, w. (cd.): catalogue of con­ odonls, 3, p. 203-230, i-lindeodlls-pl. 1-2, sehwe­ it zerbart'sche verlagsbuchhandlung, stuttgart. sweet, w.e. (1992) : a conodonl-based high-resolu ­ tion biostrat igraphy for the permo-triassic bound­ ary inlerval. in: sweet, w .c.,yang, z., dick­ ins, i.m. & yin, h. (cds.): permo-triassic evenls in ihe easlern tclhys, 120-133, cambridge univer­ s ity press, cambridge, new york, port chester, melbournc, sydncy. geologia cro:liica 49/[ sweet, w.e. & clark, d.l. ( 1981): family anchi­ gnalhodonlidae. in: moore, r.e. (foundcr) & robison, r.a. (ed.): trealise on inve rlebrale paleontology. part w, miscellanea, supplement 2, conodonta, wi66-vv169, bou ldcr and lawrence. teichert, e., k ummel, b. & sweet, w. (1973): permi an-triass ic strata, kuh-e-a li bashi, north­ western 1i"an. bull. mus. compo zool , 145/8, 359472, cambridge. tian, s.-g. (1993): lale permian-earliest triassic con­ odont pal eoecol ogy in northwcstern hunan. acta pal aeon!. siniea, 32/3, 332-345. tian, s.-g . (1994): evolulions of eonodonl ge nera neogondolella, hindeodus and lsarcicella in north­ western hllllan, china. stral falconi. c hina, 2 (1993),173-191. wang, e. -y. (1994): a conodonl-based high-resul u­ tion eventostrati graphy and biost ratigraphy for the permian-triassic boundaries in south china. palae­ oworld, 4, specia\1ssue: permian stratigraphy, envi­ ronments and resources, 1: palaeontology & strati g­ raphy, 234-248, nanjing. wang , c.y. (1995a): conodonls from ihe pe rmian­ triass ic boundary beds and biostratigraphic bound­ ary in the zhongxin dadui section a t m eishan, changxing county, zcjiang province, ch ina.­ albertiana, 15,13 -1 9, ulreeh!. w ang, c.-y. (1995b): conodonls of ihe pennian-t ri­ assic boundary beds and biostratigraphic boundary.­ acta palaeonlologiea sinica, 34/2,130-151. wang, e.-y. , kozur, h., ishiga, h. , kotly all., g.y ., ramoys , a., wang, z.-f-!. & zacha ­ roy, y. (1996): permian -triassic boundary al meishan of changxing county, zhejiang province, china a proposal on the global stratotype section and point (gs sp) for th e basc of the triass ic. in: pirst asian conodont symposium. acta m icropale­ on!. siniea, 13/2, 109-124, be ijing. wang , c. -y. & wang, z. -h. ( 1979): permian con­ odonts from the longtan formation and changhsing formation of changxing, zhcijiang and their strati ­ graphical and paleoecological significancc. select­ cd papers on the 1st convention of mi cropalaeonto­ logical society of china, 114-120, beijing. wignall, p.b., kozur , h. & h allam , a. (l996): on thc timing of palaeoenvironm ental changes at the pe rmo-triass ic (p{fr) bou ndary lising conodont biostratigraphy.histor. iliol. , 12, 39-62, amsterdam. yang, z., w u, s., yin, h. , xu, g., zhang, k. & bi , x. (1993): permo-triassic cvents of south chi ­ na. 153 p., geological publishing house, beijing. yang , z. , yin, h., wu, s., yang, r., ding, m. & xu, g. (1987) : permian-triassi c boundary s trati gkowr: the conodonts l-lil1dcodw;, {sareicella and slt'cc/oililldeodlls ... faphy and fauna or south china. prc ministry geol. min. res., geol. mem., sci'. 2, v, 6, 379 p., beijing. yin , h. (1985): on the transitional beds and the penni­ an-triassic boundary in south china.newsl. stral, 15/ 1, 13-27, berlin-s tuttgart. ytn, i-i. (1993): a proposal for the global stratotype section and point (gssp) of the permian-triassic bound:.uy.albertiana, 11 ,4-30, utrecht. yi n, i-l. , wu, s, ding, m" zhang, k, tong, j. & yang, f. (1994): the meishan section candidate of the global stratotype section and point (gssp) of the pcrmian -triassic boundary (ptb). albertiana, 14,15-31 , utrecht. yin, ii. , yang, r., zliang, k. & yang, w. (1988): a proposal to (hc biostratigraphic criterion on per­ mianffriass ic boundary. mem. soc. geol. il, 34, 329-344. yin , ii. & zhang, k. (1996): eventostrat igraphy of thc permian-triass ic boundary at meishan section, south china.in: yin, i-l. (cd.): the palaeozoic ­ mesozoic boundary. candidates of global stratotype section and point of the permian-triassic boundary. 84-96, \,yuhan, china university of gcoscienes press . youngquist, w.l & miller, a.k . (1949): con­ odont s from the latc mississippian pella beds of south-central iowa. j. palcont. , 23, 617-622. 105 zhang, k. (1987): the permo-triassic conodont fau­ na in changxing area, zhejiang province and its stratigraphic significance.earth sci. journ. , wuhan call. gcol., 12/2, 193-200, wuhan. zhang , k., ding, m., lat, x . & liu, j. (1996): conodont scquences of the permian-triassic bound­ ary strata at meishan section, south china.in: yin, h. (eel.): the palaeozoic-mesozoic boundary. candidatcs of global stratotype section and point or the permian-triassic boundary. 57 -64, wuhan, chi­ na univcrsity of geosciencs press. zhang , k., lai, x., ding, m., & liu, 1. (1995) : conodont sequence and its global correlation of permian-triass ic boundary in mcishan scction, changxing, zheijiang provincc. earth science, j. china univ. gcosci., 20/6, 669-676, wuhan. zhao, j. -k., liang, x.-l. , & zheng, z. ( 1978) : late permian cephalopods of south china.­ palacon!. sinica, n.s., b 154, 194 p. zhao, j. -k., sheng, j. -z., y ao, z. -q., liang, x.­ l., chen, c.-z., rul, l. & llao, z. -t. (1981): latc changxingian and permian-triassic boundary in south china.bull. nanjing inst. geo l. palaeont., acad. sinica, 2, ! i 12, nanjing. manuscript received february 12, ! 996. revised manuscript acceptcd may 27, 1996. log geologia croalica 49/1 plate i 1-3, 5, 6 hindeodlls iypicalis (sweet), pa clement, x i 00, araxilevis beds (lowennost dzhulfian = middle wuehi ­ apingian), clarkino /eveni zone, achura (azcrbaidzhan); for sample locations see kozur el a1. (1978, fig. 1); figs. 1, 3: sample 10/4, rep. -no. pk 1-5; fig. 2: sample 10/3, rep. -no. pk 1-8; figs. 5, 6: sample 10/2-2, rep.-no. pk 115. 4 i-jilldeodlls iypicalis (sweet), pa element, xloo , sample ac 6 (sec kozur et ai., 1975), lower dzhulfi ­ an (middle wuchiapingian) , kuh-e-ali bashi at julra, northwest iran, rep. -no. ko 5740. 7 hindeodlls iypicalis (sweet), sb element, x95, sample 10/3 , araxilevis beds (lowermost dzhulfian = middle wuchiapingian) , clarkina fe ven i zone, achura (azcrbaidzhan), rcp.-no. pk 1-5. 8 hindeodlls lypicalis (sweet), m element, x95, sample 10/3, araxilevis beds (lowermost dzhulfian = middle wuchiapingian), clarking leveni zone, achura (azerbaidzhan), rcp.-no. pk 1-8. 9 hindcodus jllllel/sis (sweet), pa clement, advanced form with only 4 free denticles between the cusp and the smooth hump, x210, samp le ar 35 (see kozur et ai., 1975) , lower dorashamian (lower changxingian), kuh-c-ali bashi, northwest iran, rep.-no. kmr 19751-1. 10 /-lilldeodus laridentatus praeparvlis n.subsp., pa clement, specimen very similar to the h. lotidentatlls loti­ delllallls (kozur , moster & rahimi-yazd) , transitional form to this subspecies, x150, tesero oolite, 2 iii above the bellerophon limestone, horizon with changxingian brachiopods, upper changxin­ gian, tesero (southern alps, ita ly), rep-no. ko 8992. 11 /-/indeodlls {atidentallls praeparllvus n.subsp., sb element, x160, tesero oolite , 2 m above the beuerophon limestone, horizon with changxingian brachiopods, upper changxingian, tesero (southern alps, italy), rep. -no. ko 9208. kozur plate ! 107 108 geologia croatica 49/1 plate il 1-3 hine/eodus fatidenlalus praeparvlfs n.subsp. , pa eleme nt , tesero oolite, upper changxingian , tesero (sollthern alps , italy); fig. 1: x200, 2 m above the beuerophon limestone, hori zon with changx ingian brachiopods, rep. -no. ko 899 1; fi g. 2: holotype, x 180, 1.5 m above the bellerophon limestone, rep.-no. ko 9003; fig. 3: x200, 1.9 m above the bellerophon limestone, rep.-no ko 8986. 4 i-l indeodus laridentatus praeparvus n.subsp. , pa clement, x220, tesero oolite, upper changxi ngian, 0.3 in above the bellerophon limestone, sass de putia section (southern alps, italy) , rep.-no. ko 8992 a. 5 hilldeodlls parvlis (kozur & pjatakov a), pa element, slightly oblique later-lower view, primitive form, x 160, upper boundary bcd 2, meishan section , re-figured from zhang (1987). 6 '-linc/eac/us parvus ereetus n.subsp., pa element , ho[otype, the same specimen as in wang ( 1994, pi. 1, fig. i); x120, zhongxin dadui quarry of meishan secti on, sample 882-4, upper part of boundary bed 2 ( 1216 em above it s base), h. parvlis zone of lowermost triassic, rep.-no. 123254. 7 hilldeodlls parl'l/s pari' lis (kozur & pjatakova), pa element, x95 , sample 10/1 3 a-2 (see kozur et ai. , 1978), i. isarcica zone, achura (azerbaidzhan), rep. -no. pk 1-7. 8 hille/eac/us parvus erecllis n.subsp. , pa clement , x95, sample 1o/l3al be low the lower stromatolite hori ­ zon, i-i. parvl/s zone, achura (azcrbaidhan), rep.-no pk 1-4. 9, 10 i-lindeodlls pos/parvlis kozur, pa element , x95 , sample 10/1 3 a-2 (sec kozur et ai. , 1978), i. isarcica zone, aehura (azerbaidzhan), rcp. -no. pk 1-7. kozur plate ii 109 110 geologia croalica 49/1 plate iii 1 ~3, 510 hindeodus parvlis erectlls n.subsp. from a monospecific fauna of predominantly juvenile specimens, sample ko 14 (thin laminated limestone intercalation in 2 m thick yellowish-brown weathered, laminat­ ed, origi nally pyritic claystone at the base of the triassic), h. parvlls zone. section east of the road, 350 m south of p ie tra dei saracini , sos io valley, western sicily (italy) , rep. -no. ko 1994/11 (if not other­ wise indicated); figs. 1-3 : pa element of jll ven ile specimens , fig. i : x230, fig. 2: x200, fig. 3 : x200, rep.-no. 16-8-95/l-18; fig. 5: m element , x 170; fig. 6: sb element, cllsp and anteriormost denticle of the posterior bar on the strongly inward bent pan of the unit , x140; fig. 7: pb element. x2 10; fig. 8: sc e le­ ment, x130; fig. 9: pa element o f adult specimen, x200, rep.-no. 16-8-95/lio, a) lateral view, b) lipper view; fig. 10: sb element, cusp on the strongly inward bent part of the unit , x200, rep.-no. 16-8-95/1-17. 4 hine/eoc/us parvlls erectll s n.subsp., sa e lement, x200, sample ko 12 a, uppermost part of graded cal­ carenites of unit 2 (sensll gullo & kozur , 1993) , i. isarcica zone, lower triassic section 350 m soll th of pietra dei saracini (sosio valley, sicily), rep.-no. komo 14-4-94/v -34. 11 hindeodlls cf. parvus ereclus n.subsp. , pa element, specimen with unu sually broad, di stally rounded den tic les, x200, sample ks 3 (floated block) , lowennost triassic graded calcarenite, east o f the road 350 m soll th of pietra dei saracini , sosio valley, western sicily (italy), rep.-no. k 1994/1-2, a) lateral view, b) lipper view. kozur plate iii iii 112 geologia croatica 49/1 plate iv h il/deadlls cl lypicalis (s weet), pa element, slender cusp and a part of the denticles are broken and regenerated, therefore their original length may be larger, x95, sample ks 3 (floated block), lowermost triassic graded calcarenite, east orthe road 350 in south of pietra dei saracini, sosio valley, western sici­ ly (italy), rep.-no. 4-12-94/y1-19. 2-4 hilldeodlls sosioensis n.sp., xioo, sample ks 3 (see fig. 1); fig. 2: pa element, holotype, rep. -no. 4-1294/yi-14; fig. 3: pb element, rcp.-no. 412-94/yi17; fig. 4: sb element, rep.-no. 4-12-94/y l-is. 5 hindeodus parvl/s onterodelltafus (dar, tian & zhang), pa element, primitive specimen, transitional to h. parv/./s erecflfs, xlso, sample ko 12 a, uppermost pari of graded calcarenites of unit 2 (sensu gul­ lo & kozur, 1993), i. isarcica zone, lower triassic section 350 m south of pietra dci saracini (sosio valley, sicily), rep.-no. komo 12-11-91/v -2. 6 hilldeodlls parvlis cree/lis n.subsp., pa element, specimen with very high blade to demonstrate the large intraspecific variability, xiso, sample ks 4 (floated block), lowermost triassic graded calcarenite, cast of the road 350 m south ofpietra dei saracini, sosio valley, western sicily (italy), rep.-no. 4-12-94/vi-22. 7 hilldcodus parvus erectus n.subsp., pa element with distally rounded denticles, x200, sample ks 3 (see fig. i), rep.-no. ko 1994/1-3, a) lateral view, b) upper view, cup not thickened . 8 isareieella? tllrgida (kozur, mostler & rahim 1-yazd), pa element, primitive form, thickened and ullthickened part of the cup nearly of the same width, x200, sample ks 3 (see fig. 1), rep.-no. ko 1994/1-4, a) lateral view, b) upper view, thickened inner part or the cup well recognizable. 9 isarcicella? prisco n.sp., pa element, holotype, re-figured from perri (1991, pi. 3, fig. 1), x9s, sample bu 10, lower tesero oolite, upper changxingian, bulla section, sw of ortisei (southern alps, italy), locality and sample data see perri, 1991, rep. -no. ie 1444, a) lower view, b) upper view, c) lateral view. kozur plate iv 113 "' geologia croatica 49/1 plate v 1 hindeodus cliangxingcnsis wang, pa element, x 80, sample 882-1, lower 4 em of bcd 27 (boundary bed 2), uppermost changx ingian, zhongxin dadui quarry of meishan section , south china (see figs. 1, 2), rep.·no. ael·882· 1/l23246. 2 hilldeodlls cilangxillgellsis wang, pa elemenl, specimen figured by wang (1994, pi. i, fig. 11) and wang (1995 b, pi. 3, fig. i ) as hindeodlls jlli/ellsis (sweet), x82, sample 882·3, al 8· 12 em above the base of bcd 27 (boundary bed 2), lowermosl triassic, lower h. parvlis zone, zhongxin dadui quarry of meishan seelion, soulh china (sec figs. 1,2), rep. · no. ael·882·3/l23247. 3 sweetohindeodus bidenfatus n.gen. n.sp. , pa element, lateral view, x280, sample ko 12 a, uppermost part of graded calcarenites of uni t 2 (sensu gullo & kozur, 1993), i . isarcica zone, lower triassic sec­ tion 350 m soulh ofpietra dei saracini (sosio valley, sicily), rep.·no. 121191/ix·3 . 4 swectohindeodus bielentallis n.gen. n.sp., pa element, ho[otype, sample ko 12 a (see fig. 3) , rep. -no. 1211 ·91/ix·2, a) upper view, x260, b) lateral view, x170. 5 sweetohifldeodlls iridenlallis n.sp. , pa element, holotype, sample ko 12 c, upper beel of the graded lime­ slone (unit 2 by gullo & kozur, 1993), i . ism'cica zone, localily as for fig. 3, rep. · no. 12·11 ·91/ix· i, a) upper view, x200, b) lateral view, xiso. 6 !soreicella ism"ciea staeschei (dar & zhang), xlso, sample 21.4, 1. isarcica zone, dorasham ii (for sample data see kozur el ai., 1978), rep. ·no. ko 1465, a) lateral view, b) oblique lateral view 10 show the transition of the thickened inner part of the cup to the unthickened marginal pari of the cup, c) upper view. 7,8 isarcicella? tllrgida (kozur, mostler & rahim!· y azo), pa element; fig. 7: latera l view, x120, sampl e 2092, unit 2 sensu gullo & kozur (1993), middl e pari of the upper bed of the 2 m thick low· er calcarenite hori zon, lower i. ism"clea zone, lower brahmanian ("induan"), section 350 iii south of pietra dci saracini , sosio valley area, sicily, rep.-no. g 91/ix-15; fig. 8: upper view of an other speci­ men, x80, sam ple ko 12 b, age and locality as for fig. 7, rep.-no. 12-11-91/ix-4. 9 10, 11 isarcicella isarcica isarcica (i-juckriede), pa element, latera l view, x 150, sample 2 1.4 (see fig. 6), rep. · no. ko 1467. hyphae of marine fungi (ascomycetes), probably of tympanicysta stoschiana balme, upper changxin­ gian tesero ool ite, 0.30 in above the bellerophon limestone, sass di putia section (southern alps, italy); fig. 10: x11 0, rep.·no. ko 8984; fi g. 11: isolated hypha, x200, rep. ·no. ko 8975. kozur plate v 115 116 geologia croalica 49f1 ab stra ct geochemical analysis and trace element distribution were performed on the marine sediments from short cores (30 to 50 cm) from the middle (jabuka and palagruža pits, depth 230 m and 170 m, respectively) and south adriatic sea (depth 1030 m) and the albanian offshore (50 m depth). the distribution of trace elements (as, co, cd, cu cr, ni, zn, hg, and pb) and major elements (al, ca and mn) and mineralogy in the sediments is presented. sediments are highly heterogeneous and consist of carbonate and detrital aluminosilicate minerals. the main mineral phase is calcite, followed by quartz, feldspars, micas and clay minerals (smectite, chlorite, illite and kaolinite). the cores were dated using 137cs. the cores from the south adriatic pit and palagruža sill gave estimated sedimentation rates of 1.8 mm y–1 and 3.1 mm y–1 in jabuka pit. distributions of ni and cr showed that they can be used as tracers of sediment provenance along the southern part of the eastern adriatic current. calculated enrichment factors for pb, cd and hg are highest in the top 2 cm of the cores. mercury shows the highest degree of enrichment in 0–2 cm sediment intervals (the highest in the albania core). generally the estimated surface enrichment follows the order: hg>pb>cd. no enrichment was found for zn, ni and cr. keywords: trace metals, accumulation rate, marine sediment record, enrichment factors, adriatic sea, eastern adriatic current geologia croatica 67/3 185–205 10 figs. 3 tabs. 3 supp. tabs. zagreb 2014 metal deposition in deep sediments from the central and south adriatic sea  nikolina ilijanić1, slobodan miko1, branko petrinec2 and zdenko franić2 1 croatian geological survey, sachsova 2, hr-10000 zagreb, croatia; (corresponding author: nilijanic@hgi-cgs.hr) 2 institute for medical research and occupational health, radiation protection unit, ksaverska cesta 2, hr-10001 zagreb, croatia doi: 10.4154/gc.2014.14 marine and estuarine environments along the eastern adriatic coast (prohić & kniewald, 1987; bogner et al., 1998; miko et al., 2007; sondi et al., 2008; cuculić et al., 2009; cukrov et al., 2011, obhodaš et al., 2012; lovrenčić mikelić et al., 2013). trace metal data are also available from relatively few long cores spanning through the holocene and into the pleistocene (calanchi et al., 1996; lucchini et al., 2003) in mid adriatic depression (mad), and basin-wide low sampling density geochemical studies of surface sediments (dolenec et al., 1998; de lazzari et al., 2004). spagnoli et al. (2010) gave a detailed overview of the studies of trace elements in sediments of the central-southern adriatic sea, concluding that data indicating contamination are only limited to specifi c areas. based on the analysis of a core from the mad, calanchi et al. (1996) concluded that it is consistent with 1. introduction down-core and surface geochemical and mineralogical analysis have been successfully used as tools in reconstructing past variations in sedimentation, provenance and pollution studies of the adriatic sea. the trace element geochemistry studies of the adriatic basin can be divided into several groups, the pollution and provenance studies related to the western adriatic current (wac) along the eastern coast of italy (dinelli & lucchini, 1999; amorosi et al., 2002; dinelli et al., 2007; spagnoli et al., 2008; annibaldi et al., 2009; amorosi, 2012; goudeau et al., 2013; romano et al., 2013), the pollution related to the studies of the gulf of trieste (covelli et al., 2001, 2006, 2007; faganeli et al., 2003; covelli et al., 2006, 2007; acquavita et al., 2012; emili et al., 2012), the coastal geologia croaticageologia croatica geologia croatica 67/3geologia croatica 186 the average composition of fine-grained middle adriatic sedi ments, and that major variations in trace element concentrations depend on changes in the silicate/carbonate ratios, and the type and abundance of silicate supply. the study by tankèré et al. (2000) used a simple box mass balance mo del for mn, fe, pb, zn, cu, ni on an annual scale for the different compartments of the adriatic sea. the model was based on fluxes along the wac. they concluded that the con tribution of the northern adriatic to the rest of the adriatic sea was relatively small because of the restricted water exchange and the loss due to burial in the sediment. on an annual scale, the adriatic sea appeared to be a source of dissolved cu, mn and fe for the mediterranean sea through the strait of otranto whereas for dissolved zn and pb the adriatic sea appeared to be a net sink. for dissolved ni, inputs and outputs through the strait of otranto balanced each other. tomadin (2000) used clay mineral composition and distribution in the central and southern adriatic sea, as tracers of sediment provenance, indicating longitudinal dispersion connected with the general adriatic cyclonic circulation. he recognized fluxes directed south-westward along the italian offshore – the apennine flux (western adriatic currentwac) near the coast and padane flux in the open sea. the nw flux flows along the eastern coast (eastern adriatic current–eac, giani et al., 2012), of the central and southern adriatic basin, which he termed as the “albanian flux”. studies on the geochemistry of the core samples have been undertaken for the western part of the adriatic sea, using the geochemistry as a tracer for both provenance and pollution studies along the wac (amorosi et al., 2002; dinelli et al.; 2007; weltje & brommer, 2011; gou deau et al., 2013; romano et al., 2013). only the studies of dolenec et al. (1998) and de lazzari et al. (2004) provided geochemical data for surface sediments along the southern part of the eastern adriatic current (eac). dolenec et al. (1998) indicated that the main sources of trace element accumulation in the central adriatic were both the wac and eac. the eac was responsible for the accumulation of as, co, cr, cu and ni, v, and zn with a contribution of wac to cu, v and zn. the sources of hg were considered to be the northern adriatic and the apennine mainland (dolenec et al., 1998). the geochemistry and mineralogy of mn from the central adriatic in surface sediments was also given by dolenec et al. (1998). the albanian river inputs are considered to be major sources of co, cr, ni, v and zn in the eastern part of the southern adriatic (dolenec et al., 1998) as a consequence of weathering and erosion of catchments containing ophiolitic mélanges associated with ophiolitic sequences in the mirdita–subpelagonian zone. the high concentrations of transition metals (such as ni, co, cr and v) are one of their primary geochemical features (saccani & photiades, 2005). this study reports the depth profiles of the eight trace elements usually identified as priority contaminants in aquatic systems as, cd, cr, cu, hg, ni, pb and zn as well as mo, mn, al and ca as geogenic elements in 5 short marine sediment cores, collected at locations on a transect along the western rim of the eac. sediment cores provided evidence for the accumulation of metals in the deep sea environments of the adriatic. this study provides an insight to the possible anthropogenic influences in the area. to assess the distribution and the degree of sediment contamination and to distinguish natural and anthropogenic inputs, metal-enrichment factors (ef) were calculated (förstner & wittmann, 1981; li, 1981). mineralogical analysis was performed in order to determine the nature and their mutual comparability as well as down-core variations of the analyzed cores. based on the metal concentrations measured in both surface and deeper sediments, trace element enrichment factors were also calculated. the depth profiles represent the signature of historical contamination. radioactive isotopes (137cs) coupled with variations in elemental concentrations allowed reconstruction of the history of trace element accumulations in adriatic sediments through time. 2. study area the adriatic sea is a narrow and shallow epicontinental basin (approximately 200×800 km), forming a distinct sub-region within the mediterranean sea (figure 1). the surface area of the whole adriatic sea is 138,595 km2 (buljan & zore-armanda, 1976). the adriatic sea may be divided into three parts (figure 1): (1) the northern adriatic sea from the trieste gulf to the ancona promontory and the island of pag; (2) the central adriatic sea from the ancona promontory and the island of pag up to the transect gargano-split; and (3) the southern adriatic sea from the gargano-split to otranto. the central adriatic sea again lies on the continental shelf, but is characterized by raised areas, which sometimes emerge to produce isles, and by a large depression up to 272 m deep. the southern adriatic sea is very different and can be divided into three units: the continental shelf, the continental slope and a bathyal plain at 1233 m. the seabed is covered with sand and in some places with a mixture of sand, mud and silt. the northern part is sandy, while the middle and southern parts are dominantly covered in silt (pigorini, 1968; leder, 2004; spagnoli et al., 2008, spagnoli et al., 2010). the adriatic sea is located between two major climatic regimes. the northern part is highly influenced by the temperate and humid climate of southeast europe, while the southern part is governed by the arid conditions of the mediterranean and northern africa. the adriatic sea has a microtidal regime and is dominated by a cyclonic circulation driven by thermohaline currents (orlić et al., 1992). the surface water of the adriatic sea circulates in an anticlockwise direction. it flows parallel to the eastern coast to the north (nw direction, eac; giani et al., 2012), then turns towards the western part on the italian coastline to the south (western adriatic current – wac). global cyclonic circulation is divided into three re-circulation cells (figure 1) in the northern, central and southern sub-basins, induced by the strong bora wind and being controlled by the bathymetry of the jabuka and south adriatic pits (zore armanda & gačić, 1987; orlić et al., 1992). ilijanić et al.: metal deposition in deep sediments from the central and south adriatic sea geologia croatica 187 3. materials and methods in this study 5 box-cores were analysed, from the central and southern part of the adriatic sea (figure 1, table 1). one core was from the mid adriatic depression (“jabuka pit”, the core was termed as jabuka), while a second came from the palagruža sill (“palagruža” core). two cores are from the south adriatic pit (cores sa pit-1 and 2) and an offshore core came from the albanian coast (“albania core”). the sediment cores were collected by means of a box-corer, which provided virtually undisturbed samples up to 50 cm long. the cores were cut into 2 cm intervals, freeze-dried after coring on the boat and transported to the laboratory. samples were powdered manually in an agate mortar and figure 1: map showing the adriatic sea and locations from which sediment cores were taken. global cyclonic circulation (arrows) of the marine currents in the adriatic sea is broken into three re-circulation cells in the northern, central and southern sub-basins, being controlled by the bathymetry of the mid adriatic depression and south adriatic pits. wac=western adriatic current; eac=eastern adriatic current. table 1: list of the samples, coordinates and depths of the locations. location geographic coordinates depth (m) core length jabuka n 43˚03’10.25’’ e 15˚16’30.94’’ 230.8 50 cm palagruža n 42˚28’34.86’’ e 16˚11’27.09’’ 169.8 40 cm sa pit 1 n 42˚20’20.77’’ e 17˚47’18.21’’ 1041.4 42 cm sa pit 2 n 42˚20’44.70’’ e 17˚44’49.09’’ 1030.0 42 cm albania n 41˚43’24.33’’ e 19˚19’54.29’’ 59.0 38 cm geologia croatica 67/3geologia croatica 188 analysed for bulk mineral and geochemical composition and total mercury concentrations. the mineral composition of all samples was determined by a panalytical x’pert powder x-ray diffractometer, equipped with ni-filter cukα radiation, vertical goniometer with θ/θ geometry and a pixcel detector. scan conditions were: 45kv and 40 ma, ¼ divergence slit and antiscatter slits, step size 0.02° 2θ, time per step 2s, in the range of 5–65° 2θ. after grinding, samples were sieved through a 0.4 mm sieve and ground in mccrone micronizing mill to reduce material to <5 μm powder samples and ensure random mineral orientation. this preparation method facilitated semiquantitative analysis, according to eberl (2003). in addition, oriented samples were prepared for clay mineral ana ly sis. calcite was removed by treating the sample with buffered sodium acetate (naoac) solution at ph 5.0 in a 1:10 sediment/buffer ratio. the ph of the slurry was lowered to 5.0 using hcl. the <2μm fraction was separated from selected samples by centrifugation (1 minute, 2000 rpm) to obtain mineralogical details about the clay-size fraction and clay minerals. oriented mounts were prepared on glass slides with an eye-dropper. these samples were analyzed in air-dried, ethylene glycol-solvated, and heated (400°c and 550°c) states and scanned in the range of 2–30° 2θ. the xrd patterns were interpreted following moore & reynolds (1997). quantitative mineral analysis was undertaken using the rockjock, computer program for qxrd (rkjock.xls; eberl, 2003). the wt% of minerals in a sample was calculated from integrated x-ray intensities. the rockjock technique has been checked for accuracy using artificial mixtures and generally produced answers that are within ± 2 to 5 % of actual values (eberl, 2003). chemical analysis was conducted on all 41 samples. the dissolution of 0.25 g of sediment was performed with a mixture of hcl–hf–hclo4–hno3 acids on a hot plate until dry. the residue was then treated with diluted hcl–hno3–h2o (15% aqua regia) in a hot bath (> 95 °c) for 30 min. the resulting solutions were analyzed by mass spectroscopy using a perkin elmer elan 6000 or 9000 icp-ms for a set of 41 elements: ag, al, as, au, ba, be, bi, ca, cd, ce, co, cr, cu, fe, hf, k, la, li, mg, mn, mo, na, nb, ni, p, pb, rb, s, sb, sc, sn, sr, ta, th, ti, u, v, w, y, zn, and zr. total mercury concentration was determined after hcl:hno3 (3:1, aqua regia) extraction of subsamples by cold vapour aas. from this set of elements potential contaminants including as, cd, cr, cu, ni, hg, pb and zn were selected to evaluate metal/contamination in the cores, as well as mo, mn, al and ca as the presumed natural variables. the chemical analysis was performed at the acme analytical laboratories in vancouver, canada. the accuracy was checked with certified reference materials (gxr-2, gxr 5, and sjs-1; usgs). the accuracy for most elements analysed in reference materials was <10 % of the certified values. precision was determined by repeated analyses of both certified reference samples and randomly selected sediment samples (every 5th sample in the batch) with the resulting average coefficient of variation of approximately 5%. the five sediment cores were measured for 137cs activities in order to derive sediment accumulation rates. details of the performed analysis and calculations of accumulation rates are given in petrinec et al. (2012). descriptive data analyses (mean, standard deviation, maximum and minimum concentrations) and calculation of enrichment factors (ferguson, 1990; ridgway & shim mield, 2002) were carried out. in addition, correlation factors were calculated to determine and the island of pag up to the transect gargano-split; asses the processes involved. the data sets for the analyzed cores (this study) and the data from dolenec et al. (1998) were analyzed using the statistica 7 (statsoft, 2006) statistical program. the comparison of geochemical data available for adriatic marine sediments given by dolenec et al. (1998) and goudeau et al. (2013) was possible since the same methods based on dissolution with the mixture of hcl–hf–hclo4– hno3 for determination of element contents were used in their studies. 4. results 4.1. sediment characteristics mineral composition of analysed sediment samples is shown in figure 2, and table 2. the predominant mineral phase in all samples was calcite (14–34%), the highest values were in palagruža (28–34%) and the lowest in the albania samples (10–15%). mg-calcite was present in all samples in concenfigure 2: mineral composition of the representative samples from the five locations. symbols: qtz-quartz, cal-calcite, kfs-potassium feldspar, plg-plagioclase, ms/i-muscovite/illite, sm-smectite, chl-chlorite, kln-kaolinite, pxpyroxene, amph-amphibole, mg-cal-mg calcite, hl-halite. ilijanić et al.: metal deposition in deep sediments from the central and south adriatic sea geologia croatica 189 trations from 1–7%, and seems to be higher in palagruža (up to 10%). quartz occurs in amounts from 3–15% and it was higher in samples from albania (10–15%) and lower in palagruža (2–10%), (figure 3). feldspars are also abundant, and potassium feldspars dominate over plagioclase. trace amounts of pyroxene and amphibole appeared in some samples. clay minerals are represented by smectite, illite, chlorite and kaolinite (figure 4). smectite is the dominant clay mineral in all the analysed sediment cores (15–43%), but with a slightly lower presence in the albania cores (18–27%). illite and chlorite have the highest contents in sediments from the albania core (7–18%, 11–16%, respecti vely), while illite was depleted in the palagruža core (3–9%). kaolinite is present in all samples, and the content ranging from 1–9%. 4.2. accumulation rates the highest sedimentation rates have been found in the cores from albania (~4 mm/y) and jabuka (3.1 mm/y), and 1.8 mm/y in palagruža. in the south adriatic, where two peaks are more easily identified, sedimentation rate could be estimated to be approximately 1.8 ± 0.5 mm/y which is quite similar to the value estimated for palagruža. results indicate that for the palagruža sill and the south adriatic pit, an annual average sedimentation rate of 1.8 ± 0.5 mm is likely and that the top 10 cm interval of the sediment core represents approximately 50 years of history and a 40 cm core could be an equivalent to 200 years. the jabuka and albania cores therefore span much shorter histories (approximately 130 and 100 years, respectively). however, it should be noted that these results are only approximate due to the method limitations and large uncertainties in the estimation of the exact location of 137cs activity concentration peaks in the sediment profiles. 4.3. variations of elemental concentrations with space and depth the tables containing geochemical data are given as online supplementary tables. the concentrations of analyzed major and trace elements are summarized in supplementary table 1. the down-core contents of major elements ca and al distable 2: quantitative mineral analysis of the samples (sa pit 1, sa pit 2, jabuka, palagruža, albania) (rockjock; eberl, 2003). results are in wt% and represent average data of the samples in the 10 centimetre interval. jabuka palagruža sa pit 1 minerals 0–10 10–20 20–30 0–10 10–20 20–30 0–10 10–20 20–30 quartz 8 7 6 9 12 8 9 7 8 calcite 23 29 30 22 12 27 23 24 24 mg-calcite 4 4 5 5 2 2 4 4 4 k-feldspar 6 8 9 5 8 7 7 7 6 plagioclase 5 6 7 5 8 6 7 4 5 illite 5 5 6 10 11 7 10 9 10 smectite 33 23 23 26 24 24 37 26 25 chlorite 9 7 7 8 14 9 12 8 9 kaolinite 4 6 5 6 6 5 5 6 6 pyroxene 1 1 1 1 – 1 – 1 1 amphibole 1 3 2 2 2 3 3 1 2 halite 1 2 2 2 2 2 2 2 1 sa pit 2 albania minerals 0–10 10–20 20–30 0–10 10–20 20–30 quartz 13 13 6 9 9 7 calcite 13 13 20 21 23 20 mg-calcite – 1 3 4 2 2 k-feldspar 7 7 7 7 6 6 plagioclase 9 8 5 5 6 6 illite 14 15 6 11 8 6 smectite 21 21 32 24 29 34 chlorite 13 12 10 9 9 11 kaolinite 7 7 5 6 5 4 pyroxene – – 3 – – 2 amphibole 2 2 2 2 3 2 halite 1 1 1 2 2 2 geologia croatica 67/3geologia croatica 190 play narrow ranges in the individual cores. the ca concentrations are highest in the palagruža core (13.68–16.81%) and the lowest in the albania core (4.83–5.19%). several samples that have higher ca contents and fall outside the cacalcite line indicate ca to be linked with some aluminosilicate phases (smectite, chlorite). relationships between major elements ca, al, ti and calcite and muscovite/illite in figure 5 clearly display these relationships. most samples in the cores contain on average < 30% smectite and < 10% chlorite with the exception of the albania core where the contents of chlorite range from 12–14% (table 2). such a deviation in ca content that is not related to carbonate content could be attributed to the presence of ca-rich plagioclase, as a signature of a high detrital siliciclastic input. the cores from the mid adriatic depression (jabuka) and south adriatic pit (sa pit 1&2) have similar ca content (11.1% and 10.7%, respectively) as well as calcite (20–24%). al and ti contents are indicative of detrital delivery and the highest contents are in the albania offshore cores. average al content ranged from 6.6% in the albania core to 4.9% in the palagruža core. the cores from the depressions had average al contents from 5.7 % (jabuka) to 6.1% (sa pit). ti contents were similar in the jabuka, sa pit and palagruža cores (supplementary table 1), while it was higher in the albanian core (0.34 to 0.37%). these elements and their relationship to trace elements are important in evaluating possible pollution. the trace element composition of the analyzed cores shows higher spatial and down-core variability (supplementary table 1). the down-core concentration profiles of pb, hg, zn, cd, cr, ni, cu, as, mo mn and zn are presented in figure 6. the mean concentrations of cd in the cores range from 0.06 mg/kg (sa pit1) to 0.14 mg/kg (albania). these concentrations correspond to the median of 0.11 mg/kg given by de lazzari et al. (2004), although their data shows large variability across the northern and central adriatic with a concentration range from 0.04 to 0.97 mg/kg. the highest concentration of cd determined in the albania core was in the deeper part of the core (22–24 cm). total mercury concentrations in the sediment cores range from 13 to 106 μg/kg, with the mean concentration between 26 and 34 μg/kg. the hg depth profiles show a clear upward increase in the analyzed cores (figure 6), with the exception of the palagruža core where hg slightly decreases in the top section. the lower sections of the cores (sa pit, palagruža, jabuka) have low hg concentrations in a narrow range between 13 and 23 μg/kg. the albania core has higher contents of hg in the lower sections of the core ranging from 33–50 μg/kg. the jabuka and palagruža cores have generally slightly higher contents of hg in comparison to the south adriatic pit cores (figure 6). pb concentrations show a general increase in the upper core samples (figure 6), there is a wide peak in the sa core between 30–32 cm depth. this interval also contains elevated concentrations of other trace elements (ba, rb) and magnetic figure 3: distribution and abundance of calcite and quartz in the studied cores (sa pit 1 and 2 are merged into sa pit). figure 4: a representative (sa pit 1 6-8 cm) oriented sample of the clay mineral fraction, with basal reflections of clay minerals after treatments (ad-air dried, eg-ethylene glycolated, heated to 400°c and heated to 550°c). symbols: sm-smectite, chl-chlorite, ill-illite, kln-kaolinite. ilijanić et al.: metal deposition in deep sediments from the central and south adriatic sea geologia croatica 191 susceptibility that could possibly be related to tephra. there is a slight decrease of pb in the tops of the palagruža and albania cores. in all the cores the pb concentrations exhibit slight variation from 14.9 to 24.5 mg/kg, with mean values ranging from 18.1 to 20.2 mg/kg (supplementary table 1). down-core variations in cr and ni are not pronounced and the difference between the cores (supplementary table 1, figure 6) lies in the total contents along the eac transect from the albania core with the high concentrations of cr (mean 263 mg/kg), and the lowest in the palagruža core (120 mg/kg). the mean concentrations of cr in the sa pit cores (152 and 146 mg/kg) and the jabuka core (131 mg/kg) falls between these two. the concentrations of ni show exactly the same behaviour (r=0.99, supplementary table 2, figure 6). the lower ni and cr contents in the palagruža core are a consequence of carbonate dilution, since the palagruža cores contain more calcite than the other cores (table 2., figure 5). the down core distributions of mn, as, mo and cu are quite complex in the analyzed cores especially in the south adriatic pit. the concentrations of mn in the analyzed cores range from 700 mg/kg (palagruža) to 5201 mg/kg (sa pit). the down-core distribution of mn in the south adriatic pit substantially differs from that of the other core exhibiting the highest concentration (5201 mg/kg) in the 18–20 cm interval and a peak (3942 mg/kg) in the 32–34 cm interval (fig ure 6). the as concentrations in the analyzed cores were generally higher than those reported by dolenec et al. (1998) for the southern adriatic. the palagruža core samples (mean 7.4 mg/kg) and the jabuka core samples (mean 13.2 mg/kg) were within the range of the as proportions in sediments in the gulf of manfredonia (spagnoli et al., 2008). if we exclude the anomalous concentrations (64 mg/kg) measured in the bottom part of the sa pit core (figure 6), the highest mean concentrations were in the albania core (22 mg/kg). high as concentrations occur in the samples from 30–38 cm depth (figure 6). cu concentrations in the cores show similar ranges in the sap pit and albania cores with a narrow average 38.9 mg/kg and 41.1 mg/kg (supplementary table 1). the mean cu contents of both the palagruža and jabuka are lower (21.6 and 29.4 mg/kg, respectively). the positive correlation with al (r=0.83) is indicative, (as in case of the analyzed transition metals) that concentration is related to detrital aluminosilicates. similar values for the adriatic surface sediments were discovered by dolenec et al. (1998). the concentration of zn in the analyzed cores ranges on average from 68 mg/kg in the palagruža core to 105 mg/kg figure 5: relationships between the major elements (ca, al, ti) and selected mineral phases (calcite and muscovite/illite). geologia croatica 67/3geologia croatica 192 figure 6: down-core variability of pb, hg, zn, cd, cr, ni, cu, mn, and mo in the studied sediment cores. ilijanić et al.: metal deposition in deep sediments from the central and south adriatic sea geologia croatica 193 figure 6: continued. supplementary table 1: metal concentrations ranges, mean, and standard deviation (std) in the analyzed cores.   core jabuka palagruža sa pit 1 sa pit 2 albania cd (mg/kg) mean 0.094 0.094 0.087 0.084 0.122 std 0.011 0.011 0.015 0.009 0.016 min. 0.080 0.080 0.060 0.070 0.100 max. 0.110 0.110 0.120 0.090 0.140 hg (ug/kg) mean 34 31 27 26 55 std 12 5 11 15 29 min. 18 23 13 13 33 max. 51 36 60 51 106 mo (mg/kg) mean 1.36 0.70 1.24 1.66 0.84 std 0.92 0.30 0.51 0.51 0.27 min. 0.50 0.40 0.50 1.10 0.60 max. 2.40 1.20 2.60 2.50 1.30 cu (mg/kg) mean 29.4 21.6 38.9 39.2 41.1 std 2.2 2.8 3.9 3.3 2.3 min. 26.5 19.3 30.6 34.9 37.8 max. 32.5 26.4 44.5 43.9 44.2 pb (mg/kg) mean 18.1 17.5 18.8 20.0 20.2 std 2.0 2.8 2.1 2.7 1.7 min. 16.2 14.9 16.6 16.7 18.3 max. 20.7 20.7 24.5 23.9 22.2 zn (mg/kg) mean 85 68 85 83 105 std 5 6 5 3 4 min. 79 61 78 79 102 max. 91 75 102 87 112 cr (mg/kg) mean 131 120 152 146 263 std 6 6 7 8 9 min. 123 112 138 138 251 max. 138 128 164 157 276 geologia croatica 67/3geologia croatica 194 in the albania core. the high positive correlation with cr (r=0.83, supplamentary table 2) is indicative of a similar source related to detrital aluminosilicates. 5. discussion 5.1. sedimentation rates the natural and artificial radionuclide activity concentrations in the sediments from the central and south adriatic sea are comparable with other reported values from the mediterranean (othman et al. 2000) and adriatic sea (frignani et al., 2004, 2005; štrok et al., 2010). in addition, their values in seawater and sediments throughout the eastern adriatic coast indicate that the determined values do not pose a significant risk for most marine biota (petrinec et al., 2013). the adriatic sea sedimentation rates have been mainly studied in the north adriatic in which sedimentation is highly influenced by the po river (palinkas & nittrouer, 2007). therefore, sedimentation in that area is quite high, and the sedimentation rate was estimated to be between 5–18 mm/y (frignani et al, 2004.). sedimentation rates estimated for the mid and south adriatic using 137cs as a radiotracer are consistent with sedimentation rates estimated for the rest of the mediterranean sea, i.e., 1.1–8.7 mm/y (othman et al., 2000) using other radiotracer methods. palinkas & nittrouer (2007) showed that sediment accumulation on the po shelf is largely controlled by the flood sedimentation near the mouth of the main tributaries, with the highest sedimentation rates of 1040 mm/y, while in the southern area of the dispersal system, accumulation is lower (< 10 mm/y), reflecting sedimentation during non-flood periods. the available data for the adriatic sea (frignani et al., 2005) shows that about 45% of values of the accumulation rates are lower than 2 mm/y. 5.2. mineral composition the mineral composition of the analysed cores shows good agreement with calanchi et al. (1996) who described the main mineral phases in the adriatic sea sediments as quartz, calcite, dolomite, feldspars, micas, clay minerals (muscovite-illite, smectite and chlorite) with occasional occurrences of amphiboles and serpentine. furthermore, several authors (pigorini, 1968; nelson, 1972; tomadin, 2000) an  core jabuka palagruža sa pit 1 sa pit 2 albania ni (mg/kg) mean 149 122 179 175 315 std 7 8 8 7 10 min. 139 109 162 168 299 max. 156 130 192 182 323 as (mg/kg) mean 13.2 7.4 24.7 18.0 22.0 std 5.2 5.1 14.0 2.1 4.4 min. 5.0 3.0 15.0 15.0 18.0 max. 18.0 16.0 64.0 20.0 29.0 mn (mg/kg) mean 1990 892 1826 2059 820 std 1125 397 1181 900 131 min. 1120 700 882 1362 732 max. 3457 1602 5201 3156 1047 ca (%) mean 11.06 15.02 10.77 10.66 5.02 std 0.95 1.36 0.61 0.48 0.14 min. 9.95 13.69 9.27 10.05 4.83 max. 12.29 16.81 11.63 11.11 5.19 ti (%) mean 0.23 21 0.27 0.27 0.36 std 0.01 0.01 0.01 0.01 0.01 min. 0.22 0.21 0.25 0.26 0.34 max. 0.25 0.22 0.29 0.27 0.37 al (%) mean 5.73 4.94 6.12 6.06 6.56 std 0.16 0.19 0.20 0.20 0.34 min. 5.56 4.69 5.71 5.87 6.11 max. 5.98 5.14 6.59 6.36 6.92 supplementary table 1: continued. ilijanić et al.: metal deposition in deep sediments from the central and south adriatic sea geologia croatica 195 alyzed the clay mineral distribution in superficial sediments of the central and southern adriatic sea. they reported that in the mid adriatic depression, clay minerals of apenninic origin dominate, whereas in the southern adriatic sea clay minerals show a depth-controlled distribution, suggesting strong hydrodynamic selection which is indicated by relative quartz dilution in offshore cores in comparison with the near shore albania core (figure 3). the distributions of illite, chlorite, and quartz seem not to be depth related but are a consequence of the carbonate content of the sediments. apennine sediments (pelitic sediments rich in smectite) are dispersed transversally to the central basin and overlie the padane, longitudinal, southward dispersion of fine-grained sediments (illiteand chlorite-rich sediments). smectite (which is the dominant clay mineral in all the analysed sediment cores), shows the afore mentioned non depth-controlled distribution with higher mean contents in the jabuka and south adriatic pit (25%) and lower (20%) mean contents in the shallower palagruža and albania cores. this could be in accordance with the findings of tomadin (2000) and due to the southern adriatic basin turbidity currents which flow transversely to the basin carrying clay sediments from the apulian shelf and the albanian–montenegrin shelf into the bathyal basin. tomadin (2000) used the clay mineral composition and distribution in the central and southern adria tic sea as tracers of sediment provenance, indicating longitudinal dispersion connected with the general adriatic cyclonic circulation. he recognized fluxes directed south-westward along the italian offshore – the apennine flux near the coast (along the wac) and the padane flux in the open sea; and a northenward flux, along the eastern coasts of the central and southern adriatic basin, the albanian flux (along the eac). based on the contents of illite, chlorite, quartz and calcite along the eac (table 2, fig. 3) a trend is observed indicating an enrichment of calcite and depletion of the other three minerals along the eac. 5.3. geochemical considerations 5.3.1. major elements the down-core contents of the major elements ca, al and ti display narrow ranges in the individual cores. these elements and their relationship to trace elements are important in evaluating possible pollution. al, ti as well as zr, sr li, rb are considered as conservative during chemical weathering (shotyk et al., 2001; van der weijden, 2002). most methods used assume aluminum as present only in clays and detrital aluminosilicates (van der weijden, 2002) and the metals are attributed to the clay fraction. titanium is commonly hosted in high specific gravity minerals that are not easily transported aerially (reimann & de caritat, 2005) and indicates detrital, coarser fractions, deposited in higher energy environments (spagnoli et al., 2008). in supplementary table 2: spearman correlation matrix (qtz-quartz, cal-calcite, k-fs-potassium feldspar, ms/i-muscovite/illite, sm-smectite, chl-chlorite). cd hg mo cu pb zn ni mn as ca cr ti al qtz cal k-fs ms/i sm chl cd 1.00 hg 0.42 1.00 mo 0.02 0.06 1.00 cu 0.21 0.15 0.37 1.00 pb 0.43 0.51 0.41 0.53 1.00 zn 0.51 0.51 0.03 0.65 0.49 1.00 ni 0.56 0.41 –0.13 0.56 0.25 0.83 1.00 mn –0.12 –0.23 0.63 0.08 –0.06 –0.13 –0.17 1.00 as 0.17 0.38 0.33 0.74 0.40 0.62 0.59 0.22 1.00 ca –0.56 –0.50 –0.08 –0.67 –0.42 –0.93 –0.91 0.06 –0.67 1.00 cr 0.58 0.47 –0.21 0.48 0.23 0.81 0.99 –0.24 0.54 –0.88 1.00 ti 0.48 0.32 –0.10 0.62 0.22 0.81 0.98 –0.10 0.61 –0.89 0.95 1.00 al 0.24 0.11 0.19 0.83 0.27 0.76 0.74 0.06 0.70 –0.79 0.67 0.81 1.00 qtz 0.46 0.38 –0.23 0.43 0.24 0.66 0.69 –0.41 0.34 –0.61 0.68 0.62 0.54 1.00 cal –0.41 –0.35 –0.13 –0.59 –0.36 –0.75 –0.78 –0.07 –0.56 0.84 –0.76 –0.81 –0.69 –0.22 1.00 k-fs 0.43 0.13 –0.14 0.07 0.07 0.16 0.36 –0.24 0.00 –0.24 0.38 0.34 0.00 0.10 –0.27 1.00 ms/i 0.65 0.44 –0.17 0.35 0.33 0.57 0.56 –0.42 0.10 –0.56 0.58 0.51 0.40 0.69 –0.35 0.19 1.00 sm –0.51 –0.32 0.34 –0.01 –0.17 –0.22 –0.33 0.61 0.11 0.21 –0.39 –0.24 0.01 –0.65 –0.11 –0.27 –0.63 1.00 chl 0.14 0.20 0.02 0.19 0.08 0.38 0.48 0.07 0.29 –0.48 0.50 0.51 0.30 –0.18 –0.80 0.29 –0.04 0.25 1.00 geologia croatica 67/3geologia croatica 196 the analyzed cores, ti has very high correlation coefficients with ni (r=0.98) and cr (r=0.95) and correlates well with muscovite/illite (r=0.65) and quartz (r=0.62), indicating a presence in the silty fractions (supplementary table 2) (spagnoli et al., 2008). the relationships between ti, al, quartz and muscovite/illite are illustrated in figure 5. ca is mainly derived from marine biogenic carbonate and al from detrital aluminosilicates (dolenec et al., 1998 and goudeau et al., 2013). this is confirmed by a high correlation (r=0.8) between ca and calcite content indicating that most of ca is derived from calcite (supplementary table 2.). 5.3.2. trace elements the analyzed trace elements based on their distributions can be divided into 4 groups; a) the “pollution”-related elements pb, hg, and cd (reimann & de caritat, 2005) showing a distinct concentration increase in the 0–2 cm core intervals (figure 6); b) cr and ni which are the most commonly used trace elements for sediment provenance studies in the adriatic basin (amorosi et al., 2002; dinelli et al., 2007; lucchini et al., 2003; spagnoli et al., 2010; amorosi, 2012; goudeau et al., 2013); c) zn, cu, as that display a complex distribution probably related to the clay and detrital aluminosilicate fractions with relatively high correlation (r>0.7) with al (supplementary table 2). the distribution of as and cu could also partially be controlled by redox processes (nameroff et al., 2002), but due to the lack of correlation with mn and mo they are treated as a separate group: d) redox-sensitive trace metals mn and mo which were found to be significant features of the bottom sediments of mad (dolenec, 2003) but also in numerous shallow marine sediments (anschutz et al., 2005; beck et al., 2008). lead and mercury – dolenec et al. (1998) suggested pb concentration ranges for the central adriatic sediments from 5–18 mg/kg and 7–14 mg/kg. spagnoli et al. (2010) in their overview of trace element data cited 34 mg/kg as a background value for the mid adriatic depression and 9.76 mg/kg for the albanian coast. romano et al., 2013 determined that sediments along the wac had mean pb concentrations ranging from 26–48 mg/kg. it is considered that pb emissions are a result of many human activities including coal combustion, use of leaded gasoline, metal smelting, and mining. eichler et al. (2012) gave historical pb emission estimates for the former u.s.s.r. countries which considerably increased after 1935 with maximum values between 1970 and 1975. after this peak period pb concentrations subsequently decreased and returned in the 1990s to the level of 1940−1950 (eichler et al., 2012). in the analyzed cores from the adriatic the slight decrease of lead in the surface (0–2 cm) intervals in the albania core could be interpreted as a consequence of this pb emission decrease. annibaldi et al. (2009) determined that pb concentrations in adriatic sea water have shown a substantial decrease since 2001, as a consequence of decreased pb emissions to the atmosphere in italy. the absence of this diminution in the mid adriatic depression (jabuka) and the southern adriatic pit (sa pit1) surface sediments could be explained by substantially lower sedimentation rates in the depressions, and that analysis of 2 cm intervals did not give adequate temporal resolution. the hg depth profiles show a clear upward increase in the analyzed cores and that the background hg concentration values for deep adriatic sediments are less than 25 μg/kg. mason et al. (2012) stressed that anthropogenic activities have enriched hg in the biosphere by at least a factor of three, and that it is supplied to the offshore regions in the form of wet and dry atmospheric deposition. the background values for the northern adriatic (gulf of trieste and po delta) given by covelli et al. (2006) and rajar et al. (2006) are approximately 130 μg/kg. dolenec et al. (1998) concluded that most of the hg supplied to the central adriatic was derived from the northern adriatic with minor influences from the croatian coast, where kaštela bay sediments near split could be a possible localized source (lovrenčić mi kelić et al., 2013). spagnoli et al. (2010) cite a range of 67–224 μg/kg, for the mid adriatic depression and 17 μg/kg, as the background for the coastal sediments of albania. chromium and nickel – most authors for provenance studies in the adriatic basin use cr and ni to define sources of sediment to the adriatic along the western adriatic current and its mud belt (amo rosi et al., 2002; lucchini et al., 2003; dinelli et al., 2007; weltje & brommer, 2011; amorosi, 2012; goudeau et al., 2013) influenced by sediment discharge from the po river and the apennine rivers. the ofanto river contributes most to the coastal sediments south of the gargano promontory along the south eastern coast of italy (goudeau et al., 2013). goudeau et al. (2013) concluded that a negligible contribution of mineral matter from the eastern adriatic coast is possible. using a chemostratigraphical approach in determining the spatial and temporal supply in long adriatic cores from the adriatic shelf, the mad and the south adriatic pit, lucchini et al. (2003) showed that cr and ni were supplied by the po river. the holocene sediments of mad have mean concentrations of 191 mg/kg cr and 195 mg/kg ni while the last glacial maximum (lgm) sediments have lower mean concentrations 117 mg/kg cr and 79 mg/kg ni (lucchini et al., 2003). the analyzed cores mainly lie along the western side of the adriatic and the influence by the eac is probably insignificant (goudeau et al., 2013). the mean concentrations of cr and ni for the southern and central adriatic given by dolenec et al. (1998) are lower than those in the analyzed cores but plot within the concentration ranges. the concentrations are dependent on the carbonate dilution i.e. the content of calcite in the sediment. they have high negative correlation coefficients with calcite content (supplementary table 2) and are positively correlated with the muscovite/ illite phase. high cr and ni proportions in the albania core are most probably a consequence of weathering and erosion of catchments containing ophiolitic mélanges associated with ophiolitic sequences which are part of the mirdita–subpelagonian zone. high concentrations of transition metals (such as ni, co, cr and v) are one of their primary geochemical features ilijanić et al.: metal deposition in deep sediments from the central and south adriatic sea geologia croatica 197 (saccani & photiades, 2005). the link with detrital aluminosilicates is displayed by correlation with both muscovite/illite, chlorite mineral phases (supplementary table 2). a contribution of ni and cr is also possible from the dalmatian region in the form of soil dust transported by the strong bora wind especially to the eastern side of the mad, or colloid suspensions from the eastern adriatic rivers. based on the geochemical soil data (miko et al., 2001; halamić et al., 2012), soils developed on karst in dalmatia contain high concentrations of cr (mean 119 mg/kg) and ni (mean 79 mg/kg) and due to the lack of vegetation cover are susceptible to wind and water erosion. zinc, copper and arsenic – although zn, cu and as are often considered as indicators of possible anthropogenic influences, the high positive correlation with cr (supplementary table 2) is indicative of a similar source related to detrital aluminosilicates. the concentrations fall within the ranges given by dolenec et al. (1998) and de lazzari et al. (2004) for the central and southern adriatic and spagnoli et al. (2008) for the gulf of manfredonia. also the concentrations are dependent on the carbonate dilution i.e. the content of calcite in the sediment as in the cases of ni and cr in the palagruža core. concentrations of as in the analyzed cores are generally higher than those reported by dolenec et al. (1998) for the southern adriatic, and slightly lower than those for the sediments in the gulf of manfredonia given by spagnoli et al. (2008). manganese and molybdenum – the concentrations of mn are comparable with those of dolenec et al. (1998) from the jabuka pit and the southern adriatic. the measured concentration of 3457 mg/kg is similar to the 3760 mg/kg of dolenec et al. (1998). mn in the southern adriatic according to dolenec et al. (1998) could have been derived from the detrital material from the albanian hinterland. de lazzari et al. (2004) also determined that the mn proportion was much higher in the mad than other areas of the central and northern adriatic. the albanian core has the lowest concentration of mn (732–1047 mg/kg). with the exception of the sa pit cores the other three cores show relative surface increases in mn concentrations (figure 6). dolenec (2003) described the manganate crusts at the sediment-water interface in the jabuka pit and their genesis as a result of processes linked with oxic diagenesis and the observation that sediments below 5 cm contain considerably less mn. anschutz et al. (2005) and chaillou et al. (2008), showed that in the first few centimetres of the sediment, mn undergoes several redox cycles with numerous possible reactions generally resulting in an aerobic surface layer enriched in mn (iii, iv) phases, as in the case of the albania, palgruža and jabuka cores. at deeper levels, these oxides are reduced to soluble mn (ii) (chaillou et al., 2008). the vertical distributions of mo follow a similar pattern with mn in the albania, palagruža and jabuka cores which are a consequence of the high affinity of the molybdate (moo4 2−) ion, (the soluble form of mo in oxic water), with mn-oxides in marine sediments (chaillou et al., 2008). these features are also revealed from the association of mo and mn in other sediments and ferromanganese nodules. the sediment geochemistry of mo may indicate shortterm variations in pore water chemistry, or the influence of mn diagenesis (morford & emerson, 1999). the decoupled distributions of mn and mo (figure 6) indicate that in the sa pit an anoxic horizon is present in the 2–10 cm interval. this could have led to a partial decrease in mn concentrations and authigenic enrichment of mo as a consequence of the reduction of mo (vi) to mo (iv) due to sulfate reduction (chaillou et al., 2008). in marine sediments mo authigenesis is controlled by authigenic sulphide phases (chaillou et al., 2008). the formation of mn (oxyhydroxides-oxides?) enriched layers in the analyzed cores is to a degree favoured by the presence of smectite (r =0.61) where their formation is probably as coatings on the clay minerals which are considered to be uniformly negatively charged over their (001) crystal faces (förstner & wittman, 1983). 5.4. normalization and enrichment factors trace metals may be introduced in the surface layers of marine sediments as a result of both natural processes (e.g. chemical weathering and erosion) and human activities within the catchment. the trace metals are mainly contained within the inorganic material which consists of silicate minerals such as quartz, feldspar, but more relevant micas and clay minerals and smaller amounts of metal oxides and sulfide phases. differing contents of trace element and heavy metals in sediments do not necessarily indicate varying degrees of pollution, but could reflect dissimilarities in grain size and mineralogical composition or post depositional remobilization. normalization with respect to characteristic elements used as proxies for grain size or differing sediment sources is often used to distinguish anthropogenic pollution effects from natural variability. a variety of approaches for reducing natural variability have been used to improve the statistical power in data inter-comparison (windom et al., 1989; van der weijden, 2002; reimann & de caritat, 2005). there is no consensus on the appropriate sediment component to be used for normalization i.e. to factor out the variability in natural trace element concentrations. in most cases, the source of the natural material making up the sediment has been assumed to be constant so the emphasis has been placed on accounting for the “grain size effect” (windom et al., 1989). metals are not homogeneously distributed over the various grain size fractions, and large differences in total concentrations are observed in sediment samples from a single locality. within the grain size spectrum, the finer-grained fraction consisting mainly of clay minerals, show relatively high metal contents. in the silt and fine sand fractions the metal concentrations generally decrease as those fractions are dominated by quartz and feldspars with low metal contents, although the occurrence of heavy minerals may cause an increase in selected elements (vital & stattegger, 2000; garcia et al., 2004; dinelli et al., 2007). geologia croatica 67/3geologia croatica 198 the basic geochemical approach is to normalize geochemical data by means of a conservative component the levels of which are unaffected by contaminant inputs, for example, grain size, al, fe, sc, ni, toc and li. consequently, changes/dilutions by the caco3, silica, or organic matter content, especially in the upper layers, can be corrected (förstner & wittmann, 1981) and be used for comparison with standard reference materials such average shale, upper crust (shotyk et al., 2001; van der weijden, 2002). this approach has several limitations, and was not used in this study. in particular, concentrations for crustal abundances are not appropriate because they do not represent regional background levels because element ratios differ substantially from rock type to rock type and the ratios in actual rocks do not reflect calculated or modeled crustal ratios (reimann & de caritat, 2005). typical normalization approaches identify one or several reference elements as a most frequently used conservative element. aluminum is the most commonly used conservative normalization for trace element sediment data (van der weijden, 2002, di leonardo et al., 2006, spagnoli et al., 2008), alternatively this element is replaced by sc (shotyk et al., 2001). the concentration of normalizing metal is used to establish the relationship between natural trace metal concentrations in sediments from different areas. the normalization procedure with al as a conservative element involving transitional elements was also widely used for provenance studies in the adriatic basin. here, cr/al and ni/al were useful geochemical tracers used to define sources of sediment to the adriatic along the western adriatic current and its mud belt (amorosi et al., 2002; lucchini, et al.; 2003, dinelli et al.; 2007; spag noli et al., 2008; amorosi, 2012; goudeau et al., 2013). the normalization of element contents to a reference element was applied to compensate for grain size and mineralogical effects. al and ti are generally used to estimate the percentage of terrestrial materials in marine sediments, and to subtract the contribution of detrital materials when calculating the authigenic components of marine sediments. for both pelagic and terrigenous materials-dominat ed se diments, the ti/al ratio has also been found to reflect the average grain size of silicate minerals in marine sediments (shotyk et al., 2001). elevated heavy metal concentrations in the surface layers of marine sediments are also sometimes attributed to anthropogenic heavy metal input to the environment (van der weijden, 2002). in order to verify possible anthropogenic input regarding heavy metals, enrichment factors of selected elements were calculated. also the efs were calculated for ni and cr to in order to identify possible temporal changes in the supply of these elements. figure 7: down-core variability of metal/al-normalized values in the studied sediment cores. ilijanić et al.: metal deposition in deep sediments from the central and south adriatic sea geologia croatica 199 the estimation of heavy metal enrichment (van der weijden, 2002) was made by a calculation procedure which uses concentrations of heavy metals and conservative elements from deeper layers (ridgway & shimmield, 2002) as background reference for the uppermost sediments. the ef is a concentration ratio of a given element (cnsample) to the conservative element (al in this study) in the sample (ccons.sample) with respect to the same ratio in the reference table 3: concentration values and enrichment factors (ef) for pb, hg, cd, zn, cr and ni in the top sections (0-2 cm) of the cores. core sediment interval (cm) depth (m) pb   hg   cd   cu   (mg/kg) ef (mg/kg) ef (mg/kg) ef (mg/kg) ef jabuka 0-2 230.8 20.7 1.3 51 2.9 0.11 1.3 31.78 1.1 palagruža 0-2 169.8 20.7 1.3 32 1.4 0.11 1.4 25.48 1.4 sa pit 1 0-2 1041.4 24.5 1.4 60 2.3 0.12 1.6 44.59 1.3 sa pit 2 0-2 1030 23.9 1.4 51 2.6 0.09 1.4 42.51 1.4 albania 0-2 59 20.4 1.3 106 3.6 0.1 0.9 31.82 1.0     core sediment interval (cm) depth (m) ni   cr   zn     (mg/kg) ef (mg/kg) ef (mg/kg) ef   jabuka 0-2 230.8 141.3 0.9 77 0.9 85 1.1   palagruža 0-2 169.8 114.5 1.0 67 0.9 75 1.1   sa pit 1 0-2 1041.4 167.2 0.9 91 1.0 102 1.2   sa pit 2 0-2 1030 164.2 1.0 94 0.9 85 1.1   albania 0-2 59 268.2 1.1 152 1.1 103 1.1     supplementary table 3: mean values of metal/al ratios in surface sediments and cores along the eastern adriatic current (eac) transect going from albania to the gulf of trieste (nas tri), and along the western adriatic current (wac) transect along the coast of italy to the southern adriatic. expl. albania, sapit1, sapit2, palagruža, jabuka cores from this study. data from dolenec et al., (1998) was classified as follows sas alb south adriatic sediments along the albanian coast, sas cro south adriatic sediments along the croatian coast, casjabuka sediments from the meso-adriatic depression, cascro central adriatic sediments along the croatian coast, nascroa northern adriatic sediments along the croatian coast, nastri sediments from the gulf of trieste, naspo northern adriatic sediments under the influence of the po river, nasap northern adriatic sediments along the eastern coast of italy, sasap southern adriatic sediments along the coast of italy. the data shown for gargano peninsula and the gulf of manfredonia is from goudeau et al. (2013). ca/al al/ti cr/al ni/al hg/al pb/al zn/al cu/al as/al albania* eac 0.77 18.2 40.1 48.0 155 3.09 16.1 6.27 3.38 sas alba 1.69 20.9 20.6 1.0 337 1.88 14.5 7.51 1.58 sa pit2* 1.76 23.0 24.8 29.3 100 3.07 13.9 6.36 4.05 sa pit1* 1.76 22.7 24.1 28.8 97 3.31 13.7 6.48 2.97 sas croa 2.17 21.5 33.9 36.1 448 2.74 16.0 5.95 3.62 palagruža* 3.05 23.0 24.4 24.8 143 3.54 13.8 4.38 1.49 jabuka* 1.93 24.4 22.8 25.9 149 3.16 14.8 5.13 2.31 cas jabukaa 2.43 22.8 26.0 26.3 677 2.21 16.3 5.52 0.51 cas croa 4.57 20.8 35.6 33.4 525 3.49 17.3 5.69 4.72 nas croa 4.42 13.6 19.2 9.1 1737 4.26 14.0 3.02 1.03 nas tria wac 2.51 19.3 18.1 13.1 1729 5.03 20.8 5.59 0.99 nas poa 2.90 20.7 17.6 9.7 1451 5.15 19.1 3.51 0.61 nas apa 2.26 23.0 13.8 8.0 2959 2.30 15.5 4.71 0.52 cas apa 2.83 22.5 19.9 18.7 775 2.49 16.0 5.61 3.28 garganob 1.65 nd 19.1 13.9 nd nd 9.7 4.20 nd manfredoniab 1.87 nd 18.9 12.4 nd nd 10.8 4.30 nd sas apa 2.49 21.2 12.4 10.9 612 2.25 13.8 6.60 0.60 *this study, a dolenec et al., 1998; b goudeau et al., (2013); nd-no data. geologia croatica 67/3geologia croatica 200 material cn ref./ccons. ref. (förstner & wittmann, 1981; li, 1981): ef = (cnsample/ccons.sample ) / (cn ref./ccons. ref.). five degrees of contamination are commonly defined (sutherland, 2000): ef < 2: deficiency to low enrichment; ef 2–5: moderate enrichment; ef 5–20: significant enrichment; ef 20–40: very high enrichment; ef > 40: exfigure 8: box plots of metal/al ratios in surface sediments and cores along the eastern adriatic current (eac) transect going from albania to the gulf of trieste (nas tri), and along the western adriatic current (wac) transect along the coast of italy to the southern adriatic. expl. albania, sapit (1&2), palagruža, jabuka cores from this study. data from dolenec et al., (1998) was classified as follows sas alb south adriatic sediments along the albanian coast, sas cro south adriatic sediments along the croatian coast, casjabuka sediments from the meso-adriatic depression, cascro central adriatic sediments along the croatian coast, nas cro northern adriatic sediments along the croatian coast, nas tri sediments from the gulf of trieste, nas po northern adriatic sediments under the influence of the po river, nasap northern adriatic sediments along the eastern coast of italy, sas ap southern adriatic sediments along the coast of italy. the data shown for gargano peninsula and the gulf of manfredonia are from goudeau et al., (2013). median 25%-75% non-outlier min-max ilijanić et al.: metal deposition in deep sediments from the central and south adriatic sea geologia croatica 201 tremely high enrichment. the down-core variations of pb/ al, hg/al, zn/al, cr/al and ni/al (figure 7) in general show some smoothing of the profiles, in comparison with elemental distributions. hg, and pb show distinct higher values in the top sediment intervals. generally the cr/al and ni/al ratios decrease from the albania core (40.1 and 48.0 respectively) along the eac transect to the jabuka core (22.8 and 25.9 respectively; supplementary table 3, figures 7 and 8). since the metal/al ratios can be applied to determine metal excesses or to account for natural changes, they were used to give an insight to the changes in trace metal proportions along the transect of the eastern adriatic current (eac) from albania, along the croatian coastal islands, through the northern adriatic and then along the western adriatic current (wac) to the south. an overview of the provenance of surface sediments along the wac on the southeastern coast of italy was given by goudeau et al. (2013). they used a multi-proxy approach which included cr/al and ni/al ratios. these data were used together with the ratios calculated from the data of dolenec et al. (1998). ratios of cr and ni (the trace metals used in provenance studies), (amorosi et al., 2002; lucchini, et al., 2003; dinelli et al., 2007; spagnoli et al., 2008; amorosi, 2012; goudeau et al., 2013), are significantly different (higher) in the southern and central adriatic along the eac (figures 8 and 9), compared to those of the surface sediments of the northern adriatic and along the wac (lower). gaudeau et al. (2013) give a cr/al ratio of 27.3 for the po river and an approximate value of 15.5 for sediments influenced by the apennine rivers. the gargano peninsula sediments and the gulf of manfredonia have mean higher cr/al ratios of 19.1 and 18.1, respectively. the values of these ratios are similar to those given by lucchini et al. (2003) for the adriatic shelf cores of both holocene and pliocene age. the cr/al ratios for holocene sediments from the mad and sa cores given by lucchini et al. (2003) have mean values higher than 23 that correspond to the cr/al ratios in the sa pit cores (24.8), palagruža core (24.4) and the jabuka core (26.0). the pleistocene sediments from the cores in the mid adriatic depression have cr/al ratios lower than 20 and are comparable to the adriatic shelf cr/al ratios (lucchini et al., 2003). the high cr/al (40.1) ratio from albania, which is a signature of weathering and erosion of catchments mirdita ophiolitic sequences, is carried as the “alba nian flux” (tomadin, 2000) along the eac. the plotted cr/al vs ni/al ratios (figure 9) for the analysed cores and the data from dolenec et al. (1998) and goudeau et al. (2013) showed that a linear dilution path between albania and the apennine (wac) signature is distorted. this indicates the possible influence of another source that is decreasing the ratios, possibly from the dinaric/dalmatian source of minerals. the distortion could also be attributed due to preferential changes in grain size towards finer fractions which were not compensated by the normalization procedure. both of these issues need to be addressed in the future through more detailed studies on a larger sample and methods with more discriminating power (not just bulk geochemical data), as well as more data from the eastern adriatic coastal sediments. the ratios from the palagruža core show a tendency towards the apennine ratios indicating a possible influence from the wac (figure 9). the mean ca/al ratios (supplementary table 3) along the aec indicates an increase of calcite/carbonate from albania (0.77) along the eastern side of the northern adriatic (4.42) and then a decrease along the wac (2.26) and the gargano peninsula and gulf of manfrefigure 9: the relationship between ni/al and cr/al ratios. the albania, sa pit, palagruža, jabuka cores are from this study. data from dolenec et al. (1998) includes the sas-south adriatic sediments, cas-central adiatic sediments; nas-north adriatic sediments. the data shown for the gargano peninsula, gulf of manfredonia, strait of otranto, po di goro and the apenninic rivers are from goudeau et al. (2013). geologia croatica 67/3geologia croatica 202 donia have ca/al ratios (average 1.65 and 1.87) similar to the sa pit (1.76) cores. the ratios for “pollution elements”, pb/al, hg/al and zn/al (supplementary table 3, figure 8) were only available for the data from dolenec et al., (1998) and show that the lowest values are in the southern and central part of the eastern adriatic and that high values characterise the northern adriatic sediments. the down-core distribution of estimated efs for hg, cd, zn, cu, pb, ni and cr are given in figure 10. the calculated efs for the top interval (0–2 cm) of each core are given in table 3. the estimated efs in the sediments show that only hg can be considered as a moderate contaminant in the analyzed cores. other elements have ef>2 but based on the classification by sutherland (2000) contaminating enrichment of trace metals has not occurred. generally the estimated surface enrichment follows the order: hg>pb>cd, the estimated efs for zn, ni and cr do not indicate any degree of enrichment. mercury has the highest calculated ef of 3.6 in the albania core while the palagruža core has the lowest one (1.4). dolenec et al. (1998) concluded that most of the hg has a source in the northern adriatic with minor influences from the eastern coast of the adriatic. the figure 10: enrichment factors (ef) estimated for pb, hg, zn, cd, ni and cr. ilijanić et al.: metal deposition in deep sediments from the central and south adriatic sea geologia croatica 203 possible contribution from the eastern coast was detected by cuculić et al. (2009) who measured 10 times higher than average hg concentrations in malo jezero on mljet island (located along the rim of south adriatic pit) during a heavy rainfall event with strong easterly winds. 6. conclusions this study reports the concentrations of the eight trace elements usually identified as priority contaminants in aquatic systems as, cd, cr, cu, hg, ni, pb and zn as well as mo, mn, al, ti and ca as lithogenic elements, in 5 short marine sediment cores, collected at locations on a transect along the western rim of the southern part of the eastern adriatic current (eac). the sediment accumulation rate for the palagruža sill and the south adriatic pit is ~0.18 cmy–1 and the top 10 cm interval of the sediment core represents approximately 50 years and a 40 cm core could have an equivalent to 200 years of deposition. the jabuka and albania cores presumably span shorter times (approximately 130 and 100 years, respectively). the sediments are highly heterogeneous and consist of carbonate and detrital aluminosilicates. the main mineral phase is calcite, followed by quartz, feldspars, micas and clay minerals (smectite, chlorite, illite and kaolinite). the trace metal down-core distributions and relations with mineral and clay composition allowed the distinction of several groups of trace metals. the “pollution elements” pb, and hg showed increased concentrations in the top sections of the cores. concentrations of redox-sensitive metals, mn and mo have vertical distributions that followed similar patterns and were used to identify the redox state of sediments. the downcore distribution of redox-sensitive trace metals are complex in the south adriatic pit core. the metal/al ratios were applied to determine metal excesses or to account for natural changes. they were used to give an insight to the changes in trace metals along transect of the eastern adriatic current (eac) from albania, along the croatian coastal islands through the northern adriatic, and then along the western adriatic current (wac) to the south. the cr/al and ni/al ratios used for provenance discrimination have ratios that are significantly different (higher) in the southern and central adriatic along the eac compared to those of the surface sediments of the northern adriatic and along the wac (lower). the plotted cr/al vs ni/al ratios for the analysed cores, along with the available literature data (dolenec at al., 1998; goudeau et al., 2013) show that a linear dilution path between albania (along the aec) and the apennine (wac) signature is distorted. this could indicate the potential influence of another source that is decreasing the ratios, possibly from the dinaric/dalmatian source of minerals. the distortion could also be attributed to preferential changes in grain size towards the finer fractions which were not compensated by the normalization procedure. both of these issues need to be addressed in the future through more detailed studies on a larger sample and methods with more discriminating power (not just bulk geochemical data), as well as more data from the eastern adriatic coastal sediments. generally, the surface estimated enrichment follows the order: hg>pb>cd, the estimated efs for zn, ni and cr do not indicate any enrichment. the estimated efs in the sediments show that only hg can be considered as a contaminant in the analyzed sediments. acknowledgement this study is a part of several research projects, ‘radioecology of the adriatic sea and coastal areas’, ‘environmental radioactivity and radiation protection’ and “the basic geochemical map of the republic of croatia” supported by the croatian ministry of science, education and sports of the republic of croatia and iaea tc project rer/7/003 ‘marine environmental assessment of the mediterranean region’. references acquavita, a., covelli, s., emili, a., berto, d., faganeli, j., giani, m., horvat, m., koron, n. & rampazzo, f. (2012): mercury in the sediments of the marano and grado lagoon (northern adriatic sea): sources, distribution and speciation.– estuar. coast. shelf. sci., 113, 20–31. amorosi, a. (2012): chromium and nickel as indicators of source-tosink sediment transfer in a holocene alluvial and coastal system (po plain, italy).– sedim. geol., 280, 260–269. amorosi, a., centineo, m.c., dinelli, e., lucchini, f. & tateo, f. (2002): geochemical and mineralogical variations as indicators of provenance in late quaternary deposits of se po plain.– sedim. geol., 151, 273–292. annibaldi, a., truzzi, c., illuminati, s. & scarponi, g. (2009): recent sudden decrease of lead in adriatic coastal seawater during the years 2000–2004 in parallel with the phasing out of leaded gasoline in italy.– mar. chem., 113, 238–249. anschutz, p., dedieu, k., desmazes, f. & chaillou, g. (2005): speciation, oxidation state, and reactivity of particulate manganese in marine sediments.– chem. geol., 218/3–4, 265–279. beck, m., dellwig, o., schnetger, b. & brumsack, h.j (2008): cycling of trace metals (mn, fe, mo, u, v, cr) in deep pore waters of intertidal flat sediments.– geoch. cosmoch. acta, 72/12, 2822–2840. bogner, d., juračić, m., odžak, n. & barić, a. (1998): trace metals in fine grained sediments of the kaštela bay, adriatic sea.– wat. sci. techn., 38/11, 169–175. buljan, m. & zore-armanda, m. (1976): oceanographical properties of the adriatic sea.– ocean. mar. biol. ann. rev., 14, 11–98. calanchi, n., dinelli, e., lucchini, f. & mordenti, a. (1996): chemostratigraphy of late quaternary sediments from lake albano and central adriatic sea cores (paliclas project).– mem. ist. ital. idrobiol., 55, 247–263. chaillou, g., schäfer, j., blanc, g. & anschutz, p. (2008): mobility of mo, u, as, and sb within modern turbidites.– mar. geol., 254/3–4, 171–179. covelli, s., faganeli, j., horvat, m. & brambati, a. (2001): mercury contamination of coastal sediments as the result of longterm cinnabar mining activity (gulf of trieste, northern adriatic sea).– appl. geoch., 16, 541–558. geologia croatica 67/3geologia croatica 204 covelli, s., fontolan, g., faganeli, j. & ogrinc, n. (2006): anthropogenic markers in the holocene stratigraphic sequence of the gulf of trieste (northern adriatic sea).– mar. geol., 230, 29–51. covelli, s., piani, r., acquavita, a., predonzani, s. & faganeli, j. (2007): transport and dispersion of particulate hg associated with a river plume in coastal northern adriatic environments.– mar. poll. bull., 55, 436–450. cuculić, v., cukrov, n., kwokal, ž. & mlakar, m. (2009): natural and anthropogenic sources of hg, cd, pb, cu and zn in seawater and sediment of mljet natinal park, croatia.– est. coast. shelf sci., 81, 311–320. cukrov, n., frančišković-bilinski, s., hlača, b. & barišić, d. (2011): a recent history of metal accumulation in the sediments of rijeka harbor, adriatic sea, croatia.– mar. poll. bull., 62/1, 154–167. de lazzari, a., rampazzo, g. & pavoni, b. (2004): geochemistry of sediments in the northern and central adriatic sea.– est. coast. shelf sci., 59, 429–440. di leonardo, r., tranchida, g., bellanca, a., neri, r., angelone, m & mazzola, s. (2006): mercury levels in sediments of central mediterranean sea: a 150+ year record from boxcores recovered in the strait of sicily.– environ. chem., 65/11, 2366–2376. dinelli, e. & lucchini, f. (1999): sediment supply to the adriatic sea basin from the italian rivers: geochemical features and environmental constraints.– giorn. geol., 61, 121–132. dinelli, e., tateo, f. & summa, v. (2007): geochemical and mineralogical proxies for grain size in mudstones and siltstones from the pleistocene and holocene of the po river alluvial plain, italy.– geolog. soc. am. spec. pap., 420, 25–36. dolenec, t. (2003): ferromanganese coated structures from the jabuka pit (central adriatic): mineralogical, geochemical and genetic considerations.– croat. chem. acta, 76/3, 201–215. dolenec, t., faganeli, j. & pirc, s. (1998): major, minor and tra ce elements in surficial sediments from the open adriatic sea: a regional geochemical study.– geol. croat., 51/1, 59–73. eberl, d.d. (2003): user guide to rockjock – a program for determining quantitative mineralogy from x-ray diffraction data.– us geol. surv. open file rep., 03–78. eichler, a., tobler, l., eyrikh, s., gramlich, g., malygina, n., papina, t. & schwikowski, m. (2012): three centuries of eastern european and altai lead emissions recorded in a belukha ice core. environ.– sci. technol., 46, 4323−4330. emili, a., acquavita, a., koron, n., covelli, s., faganeli, j., horvat, m., žižek, s. & fajon, v. (2012): benthic flux measurements of hg species in a northern adriatic lagoon environment (marano and grado lagoon, italy).– est. coast. shelf sci., 113, 71–84. faganeli, j., horvat, m., covelli, s., fajon, v., logar, m., lipej, l. & cermelj, b. (2003): mercury methylmercury in the gulf of trieste (northern adriatic sea).– sci. tot. env., 304, 315–326. ferguson, j.e. (1990): the heavy metals: chemistry, environmental impact and health effects.– pergamon, new york, 412 p. förstner, u. & wittmann, g.t.w. (1981): metal pollution in the aquatic environment.– springer, heidelberg, 486 p. frignani, m., sorgente, d., langone, l., albertazzi, s. & ravaioli, m. (2004): behavior of chernobyl radiocesium in sediments of the adriatic sea off the po river delta and the emiliaromagna coast.– j. environ. radioactiv., 71, 299–312. frignani, m., langone, l., ravaioli, m., sorgente, d., alvisi, f. & albertazzi, s. (2005): fine-sediment mass balance in the western adriatic contitnental shelf over a century time scale.– mar. geol., 222–223, 113–133. garcia, d., ravenne, c., maréchal, b. & moutte, j. (2004): geochemical variability induced by entrainment sorting: quantified signals for provenance analysis.– sed. geol., 171, 113–128. giani, m., djakovac, t., degobbis, d., cozzi, s., solidoro, c. & fonda umani, s. (2012): recent changes in the marine ecosystems of the northern adriatic sea.– est. coast. shelf sci., 115, 1–13. goudeau, m.l.s., grauel, a.l. & bernasconi, s.m. (2013): provenance of surface sediments along the southeastern adriatic coast off italy: an overview.– est. coast. sh. sci., 134, 45–56. halamić, j., peh, z., miko, s., galović, l. & šorša, a. (2012): geochemical atlas of croatia: environmental implications and geochemical thread. – j. geoch. explor., 115, 36–46. leder, n. (2004): adriatic sea pilot. part b-1. hydrographic institute of the republic of croatia. li, y.h. (1981): geochemical cycles of elements and human perturbation.– geoch. cosmoch. acta, 45, 2073–2084. lovrenčić mikelić, i., oreščanin, v. & barišić, d. (2013): distribution and origin of major, minor, and trace elements in sediments and sedimentary rocks of the kaštela bay (croatia) coastal area.– j. geoch. expl., 128, 1–13. lucchini, f., dinelli, e. & mordenti, a. (2003): geochemical records of palaeoenvironmental changes during late quaternary in the adriatic sea sediments.– geoacta, 2, 43–62. mason, r.p., choi, a.l., fitzgerald, w.f., hammerschmidt, c.r., lamborg, c.h., soerensen, a.l. & sunderland, e.m. (2012): mercury biogeochemical cycling in the ocean and policy implications.– environ. res., 119, 101–117. miko, s., halamić, j., peh, z. & galović, l. (2001): geochemical baseline mapping of soils developed on diverse bedrock from two regions in croatia.– geologia croatica, 54/1, 53–118. miko, s., koch, g., mesić, s., šparica miko, m., šparica, m., vreča, p. & dolenec, t. (2007): influence of land use in small karst watersheds on chemical status of peloid sediments on the eastern adriatic coast.– j. soils sed., 7/5, 303–312. moore, d.m. & reynolds, r.c. (1997): x-ray diffraction and the identification and analysis of clay minerals.– oxford univ. press, oxford, new york, 332 p. morford, j.l. & emerson, s. (1999): the geochemistry of redox sensitive trace metals in sediments.– geoch. cosmoch. acta, 63/11– 12, 1735–1750. nameroff, t. j., balistrieri, l.s., murray j. w. (2002): suboxic trace metal geochemistry in the eastern tropical north pacific.– geochimica et cosmochimica acta, 66/7, 1139–1158. nelson, b.w. (1972): mineralogical differentiation of sediments dispersed from the po delta.– in: stanley, d.j. (ed.): the mediterranean sea: a natural sedimentation laboratory, dowden, hutchinson & ross, stroudsburg, 441–453. obhođaš, j., valković, v., matjačić, l., nađ, k. & sudac, d. (2012): evaluation of elemental composition of sediments from the adriatic sea by using edxrf technique.– appl. rad. isot., 70/7, 1392–1395. orlić, m., gačić, m. & la violette, p.e. (1992): the currents and circulation of the adriatic sea.– ocean. acta, 15/2, 109–124. othman, i., al-masri, m.s. & al rayyes, a.h. (2000): sedimentation rates and pollution history of the eastern mediterranean sea: syrian coast.– sci. tot. envir., 248, 27–35. palinkas, c.m. & nittrouer, c.a. (2007): modern sediment accumulation on the po shelf, adriatic sea – cont. shelf. resear., 27, 489–505. petrinec, b., franić, z, ilijanić, n., miko, s., štrok, m. & smodiš, b. (2012): estimation of sedimentation rate in the middle and south adriatic sea using 137cs.– radiat. protect. dos., 151/1, 102–111. ilijanić et al.: metal deposition in deep sediments from the central and south adriatic sea geologia croatica 205 petrinec, b., štrok, m., franić, z., smodiš, b. & pavičićhamer, d. (2013): radionuclides in the adriatic sea and related dose-rate assessment for marine biota.– radiat. protect. dos., 154/3, 320–330. pigorini, b. (1968): sources and dispersion of recent sediments of the adriatic sea.– mar. geol., 6, 187–229. prohić, e. & kniewald, g. (1987): heavy metal distribution in recent sediments of the krka river estuary – an example of sequential extraction analysis.– mar. chem., 22/2–4, 279–297. rajar, r., četina, m., horvat, m. & žagar, d. (2007): mass balance of mercury in the mediterranean sea.– mar. chem., 107/1, 89–102. reimann, c. & de caritat, p. (2005): distinguishing between natural and anthropogenic sources for elements in the environment: regional geochemical surveys versus enrichment factors.– sci. tot. envir., 337, 91–107. ridgway, j. & shimmield, g. (2002): estuaries as repositories of historical contamination and their impact on shelf seas.– estuar. coast. shelf. sci., 55, 903–92. romano, s., langone, l., frignani, m., albertazzi, s., focaccia, p., bellucci, l.g. & ravaioli, m. (2013): historical pattern and mass balance of trace metals in sediments of the northwestern adriatic shelf.– mar. poll. bull., 76, 32–41. saccani, e. & photiades, a. (2005): petrogenesis and tectonomagmatic significance of volcanic and subvolcanic rocks in the albanide–hellenide ophiolitic mélanges.– the island arc, 14, 494–516. shotyk, w., weiss, d. & kramers, j.d. (2001): geochemistry of the peat bog at etang de la grue`re, jura mountains, switzerland, and its record of atmospheric pb and lithogenic trace elements (sc, ti, y, zr, hf and ree) since 12,370 14c yr bp.– geoch. cosmoch. acta, 65/14, 2337–2360. sondi, i., lojen, s., juračić, m. & prohić, e. (2008): mechanisms of land–sea interactions – the distribution of metals and sedimentary organic matter in sediments of a river-dominated mediterranean karstic estuary.– estuar. coast. shelf. sci., 80/1, 12–20. spagnoli, f., bartholini, g., dinelli, e. & giordano, p. (2008): geochemistry and particles size of surface sediments of gulf of manfredonia (southern adriatic sea).– estuar. coast. sh. sci., 80, 21–30. spagnoli, f., dell’anno, a., de marco, a., dinelli, e., fabiano, m., gadaleta, m.v. & ianni, c. (2010): biogeochemistry, grain size and mineralogy of the central and southern adriatic sea sediments: a review.– chem. ecol., 26, 19–44. statsoft, inc. (2006): statistica (data analysis software system), version 7.1, tulsa, sad. sutherland, r.a. (2000): bed sediment-associated trace metals in an urban stream, oahu, hawaii. – environ. geol., 39/6, 611–627. štrok, m., smodiš, b. & petrinec, b. (2010): natural radionuclides in sediments and rocks from adriatic sea. – j. radianal. nucl. chem., 286, 303–308. tankèré, s.p.c., price, n.b. & statham, p.j. (2000): mass balance of trace metals in the adriatic sea.– j. mar. syst., 25, 269–286. tomadin, l. (2000): sedimentary fluxes and different dispersion mechanisms of the clay sediments in the adriatic basin.– rend. lincei, 9/11, 161–174. van der weijden, c.h. (2002): pitfalls of normalization of marine geochemical data using a common divisor.– mar. geol., 184/3–4, 167–187. vital, h. & stattegger, k. (2000): major and trace elements of stream sediments from the lowermost amazon river.– chem. geol., 168, 151–168. weltje, g.j. & brommer, b. (2011): sediment-budget modelling of multi-sourced basin fills: application to recent deposits of the western adriatic mud wedge (italy).– basin resear., 23, 291–238. windom, h., schropp, s., calder, f., ryan, j., smith, r.j., burney, l. lewis, f. & rawlison, c. (1989): natural trace metal concentrations in estuarine and coastal marine sediments of the southeastern u.s. – environ. sci. technol., 23/3, 314–320. zore armanda, m. & gačić, m. (1987): effects of the bura on the circulation in the north adriatic.– ann. geophy, 5b, 93–102. manuscript received january 14, 2014 revised manuscript accepted september 25, 2014 available online october 31, 2014 2021 | 74/3 | 273–286 | 11 figs. | 1 tab. | appendix | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction caves are natural underground voids formed predominantly by the dissolution of soluble (mostly carbonate) bedrock and they act as natural windows to the earth’s critical zone (ecz). the ecz is a relatively thin, but extremely heterogeneous zone that extends from the bottom of the groundwater body to the uppermost parts of the surface vegetation in which life can be sustained by coupled chemical, biological, physical and geological processes (brantley et al., 2007) and which is most exposed to environmental changes. the natural functioning of this system is strongly regulated by climate and associated hydrological and vegetational changes which can be reliably archived within speleothems (regattieri et al., 2019). therefore, speleothembased research is increasing globally (comas-bru et al., 2020), complemented by the monitoring of cave properties such as hydrogeology, hydrogeochemistry, microclimate, cave air composition, etc., the understanding of which is essential for the appropriate interpretation of the palaeoenvironmental signals recorded in spelean carbonate. although it is just a trace gas in the atmosphere (416.49 ppm in may 2021, noaa accessed on 30 august 2021), co2 plays an important role in the overall earth system, especially when misbalanced from the natural state. on an incomparably smaller spatio-temporal variations of cave-air co2 concentrations in two croatian show caves: natural vs. anthropogenic controls maša surić*, robert, lončarić, matea kulišić and lukrecija sršen university of zadar, department of geography, ul. dr. f. tuđmana 24, 23000 zadar, croatia; (*msuric@unizd.hr) doi: 10.4154/gc.2021.21 abstract carbon dioxide (co2) concentration (cdc) plays an important role in karst processes, governing both carbonate deposition and dissolution, affecting not only natural processes, but also human activities in caves adapted for tourism. its variations due to various controlling parameters was observed from 2017 to 2021 in two croatian show caves (manita peć and modrič) where we examined interand within-cave correlation of internal aerology regarding the sources, sinks and transport mechanism of cdc in a karst conduit setting. in both caves, the main sources of co2 are: i) plant and microbial activity i.e. root respiration and organic matter decay within soil horizons and fractured epikarst, and ii) degassing from co2-rich percolation water. the main sink of co2 is dilution with outside air due to cave ventilation. chimney-effect driven ventilation controlled by seasonal differences between surface and cave air temperatures shows winter (tout<tcave) and summer (tout>tcave ) ventilation regime, which are modulated by the geometry of cave passages, the transmissivity of the overlying epikarst, and occasionally by the external winds, especially the gusty north-eastern bora wind. in these terms, the modrič cave appears to be more confined and less ventilated, with a substantial cdc difference between the left (5507200 ppm) and right (1475>10,000 ppm) passages. the manita peć cave is, in contrast, ventilated almost year-round, having 7 months of cdc equilibrated with the outside atmosphere and the highest summer cdc values of ~1415 ppm. in both caves, at the current level of tourist use, anthropogenic co2 flux is not a matter of concern for cave conservation. in turn, in the innermost part of the right modrič cave passage visitors’ health might be compromised, but the tourists are allowed only in the left passage. speleothem growth rate, recognized as a useful palaeoenvironmental proxy for speleothembased palaeoclimate studies, strongly depends on cdc variations, so the high cdcs recorded in the modrič cave indicate the potential periods with no speleothem deposition due to the hampered degassing of co2 from the dripping groundwater. the opposite effect i.e. enhanced ventilation (that supports calcite precipitation) during the windy glacials/stadials, as well as substantial vegetational changes must also be taken into consideration when interpreting environmental records from spelean calcite. scale, co2 in cave air is, in an underground environment, also important and interesting for its various sources, sinks and effects that occur with or without human interaction. generally, co2 partial pressure is one of the most important factors that controls both carbonate dissolution and speleothem deposition (dreybrodt, 1999) and the understanding of co2 distribution and dynamics in the underground is essential for various aspects of cave science including the aforementioned speleothem-based palaeoclimate studies (baldini et al., 2008; cowan et al., 2013; gregorič et al., 2013). cave air co2 concentration (cdc) is controlled by dynamic equilibrium between different co2 sources and sinks and their competing influences depending on both spatial and temporal particularities of the cave environment. the main natural sources of underground co2 are: i) diffusion of co2-rich air generated by root respiration and organic matter decay transmitted from the soil through the joints and fissures, ii) degassing from the groundwater which was enriched by co2 on its way through the soil and epikarst, iii) biological productivity i.e. decomposition (micro-organisms feeding on organic matter, usually guano) within the cave, and iv) deep-seated (thermal) geogenic sources (baldini et al., 2008; fairchild & baker, 2012; prelovšek et al., 2018). in addition to the aforementioned natural sources, show caves may receive extra article history: manuscript received may 27, 2021 revised manuscript accepted september 16, 2021 available online october 27, 2021 keywords: show cave, co2, cave ventilation, anthropogenic impact, croatia g eo lo gi a c ro at ic a 274 geologia croatica 74/3 anthropogenic co2-flux from visitors breathing (e.g. dragovich & grose, 1990; liñán et al., 2008). the most substantial sinks of cave air co2 are: i) ventilation i.e. dilution of the co2rich cave air with relatively co2-poor outside air, and ii) uptake by groundwater i.e. co2 dissolution in under-saturated cave water (cowan et al., 2013). elevated cave air cdc, increased either naturally or anthropogenically, may affect the cave environment in several ways. first, when percolating groundwater (in which co2 is controlled predominantly by soil pco2) reaches the air-filled voids, equilibration with lower pco2 cave air occurs and degassing of co2 can cause calcite precipitation from the water saturated with respect to calcite (houillon et al., 2017). however, elevated pco2 in cave air can hamper degassing of co2 from the dripping groundwater resulting in either the absence or cessation of calcite deposition (baldini et al., 2006; 2008). second, cave air co2 dissolved in water condensed within the cave produces carbonic acid which may dissolve bedrock or already crystallized spelean calcite, a process known as condensation corrosion (dublyansky & dublyansky, 1998; faimon et al., 2006; baldini et al., 2006; gabrovšek et al., 2010). thirdly, high cave air cdc values are related to health issues, so already a cdc of 5000 ppm is regarded as the occupational exposure limit (ilo, 2006), and it must be considered for all visitors in show caves, including tourists, guides, cavers and scientists. the majority of caves have elevated cdcs, usually in summer, which in some cases reach extremely high values, such as ~14,000 ppm in the romanian urșilor cave (constantin et al., 2021), ~22,000 ppm in galeria das lâminas, portugal (benson et al., 2021), ~35,000 ppm in béke cave, hungary (czuppon et al., 2018), ~31,000 ppm in district park cave and ~38,000 ppm in natural bridge caverns in the usa (cowan et al., 2013), even up to >44,000 in chauvet cave (bourges et al., 2020) and ~60,000 ppm in causse d’aumelas (batiot-guilhe et al., 2007) in france. in croatia, the first records of elevated cdc were published by malez (1954) and božičević (1966), and afterwards numerous occurrences of high cdc have been reported by cavers, but systematic monitoring began only in 2016 within 5 show caves in the continental part of croatia (bočić & buzjak, 2018). here, we present the first results of multi-year monitoring of the cave environment aimed at estimating spatial and temporal variations of cave air cdc in two show caves located in the coastal zone of the dinaric karst in croatia – the manita peć and modrič caves, both considered to be small and simple caves with relatively low numbers of visitors. the obtained data sets enabled us to: i) reveal cave ventilation dynamics in order to detect possible seasonal speleothem growth patterns crucial for palaeoenvironmental studies; ii) estimate the anthropogenic contribution to the cave co2 background levels and potential effects on the cave interior, and iii) assess the possible health hazard for the visitors from an elevated cdc. 2. study site the dinaric karst in croatia is characterized by relatively high mountain ranges (up to 1831 m) stretching parallel to the coast, one of which is velebit mountain – the host of the two studied caves. modrič cave is located in its foothill at 32 m a.s.l., while the entrance of manita peć cave is at 570 m a.s.l., on the side of the canyon perpendicular to the mountain range (fig. 1). given their geographical position and geological settings, some specific meteorological features (e.g. bora events) are expected to influence the cave atmospheres i.e. ventilation. the modrič cave (44° 15’ n, 15° 32’ e) is situated 120 m from the shoreline on the sw slope of the central part of velebit mountain. the cave is formed within a 2.5 km wide fault zone, in well-bedded upper cretaceous limestone (miko et al., 2002), and consists of two, mostly horizontal, passages with a total length of 829 m and a single narrow entrance (kuhta et al., 1999). overlying bedrock is 1-27 m thick and vegetation cover above the cave is sparse trees, bush and grassland. soon after its discovery in 1985 and an initial topographic survey, modrič cave came to the attention of various scientific disciplines and has since become one of the most investigated croatian caves (surić, 2018). palaeontological research of quaternary vertebrate faunal remnants (malez, 1987; aguilar et al., 2004) was followed by a thorough speleological and geological survey and partial geochemical and hydrogeological investigations (kuhta et al., 1999); the geochemical aspect was focused on sediments, percolating water and bat guano influences (miko et al., 2001; 2002). because the cave has been open for adventure tourism since 2004, radon activity in the cave air was occasionally monitored (buzjak et al., 2010; sršen, 2019). for the purpose of palaeoclimate reconstruction, thorough microclimate monitoring, along with speleothem and dripwater stable isotope analyses, were conducted in several campaigns from 2003 onwards (surić et al., 2010; 2017; 2020; rudzka et al., 2012). the manita peć cave (44°18’ n, 15°28’ e) is located on the steep flank of the velika paklenica canyon carved perpendicularly into the velebit mountain. it is a simple, 175 m long, descending spacious chamber formed in upper jurassic limestone, with a height up to 38.5 m and total volume of 67,510 m3 (kuhta, 2010). the overburden is up to 80 m thick and heavily fractured. ground surface cover is sparse patches of terra rossa, shrubs and grass. scientific interest for this cave had already begun in 1900 with the first biospeleological investigation, followed by geological and speleological surveys in 1929, which also included preliminary notes on its microclimate and hydrogeology. due to its rich speleothem formations, in 1937 it was adapted for visitors with construction of the first pathway and a new artificial entrance (action plans national park paklenica, 2007). in the following decades the cave has been the site of occasional environmental research projects, one of which was the monitoring of radon activity in the cave atmosphere (radolić et al., 2012). this was fundamental for assessing the health and safety of visitors and guides. although both caves are open for visitors, there is a significant difference in the approach to touristic management between them. modrič cave is available for individually arranged visits year-round, but the peak numbers of visitors occurs between april and october, with an annual maximum of 727 visitors in 2019. organized as an adventure tour with caving equipment, visitors in groups of up to 30 people spend approximately 1.5 to 2 hours within the left passage of the modrič cave. manita peć cave operates as a “classical” show cave with guided tours and no need for special equipment. according to the current timetable, during the summer (july, august, september), manita peć cave is open every day, then three days a week through the late spring and early autumn (may, june, october), finally in april only one day per week. it is closed for visitors during the winter season, except for organized groups on demand. in order to minimize anthropogenic impact, it has been open just for three hours per day, except during 2017-2018 when it was open for 4 hours per day. a maximum of ~13,000 visitors per year was reached in 2017. the usual visiting time in manita peć cave is up to 30 minutes for groups of 25-30 visitors. g eologia c roatica 275surić et al.: spatio-temporal variations of cave-air co2 concentrations in two croatian show caves: natural vs. anthropogenic controls 3. methods monitoring of cave air cdc was conducted in modrič cave from march 2017 to march 2021 in the right passage and from july 2018 to march 2021 in the left passage. in manita peć cave cdc monitoring covered the period between january 2018 and march 2021. measurements were performed on a monthly basis using a 7755 az handheld co2 & temperature & relative humidity meter (co2 range 0-9999 ppm; resolution 1 ppm; accuracy ±50 ppm or ±5% of reading (0-2000 ppm); air temperature range -10-60 °c; resolution 0.1 °c; accuracy ±0.6 °c). the measurements were carried out at the beginning of each month, on the same day in both caves. along with regular monthly monitoring, cdc was measured on several occasions before and after tourist group visits (usually 20-30 people) in spring and summer, to assess anthropogenic impact on the cave air properties. eight measurement points were established in manita peć cave, and 7 in modrič cave, distributed at approximately even distances from the entrance to the innermost parts, with additional measurement points in front of each cave (figs. 1c &1d). additionally, in the modrič cave’s right passage, air temperature and relative humidity were also continuously recorded (1-hour intervals) using onset hobo® pro-v2 u23-001 data loggers (t range -40 to 70 °c; accuracy ±0.25 °c from -40 to 0 °c; ±0.2 °c from 0 to 70 °c; resolution 0.04 °c; rh range 0 to 100%, accuracy ±2.5% from 10% to 90% rh, ±5% <10% or >90% rh, resolution 0.05%). external temperatures and precipitation data were obtained from the croatian meteorological and hydrological service (cmhs) for the station in starigrad paklenica (ca. 4 km sw from manita peć cave and ca. 9 km nw from modrič cave). however, due to the station’s technical failure, from december 2018 onwards, data for the station in novigrad (ca. 16.5 figure 1. study area with cave locations and basic climatic data for the meteorological station in starigrad paklenica (ca. 4 km sw of the manita peć cave and ca. 9 km nw of the modrič cave) for 1992-2018: a) air temperature and precipitation; b) difference between precipitation and potential evapotranspiration (croatian meteorological and hydrological service /cmhs/, 2021); c) east-facing entrance of manita peć cave and the plan with measurement points; d) north-facing entrance of modrič cave and the plan with measurement points. water balance (potential evapotranspiration) was calculated using the thornthwaite evapotranspiration model (thornthwaite, 1948; mccabe & markstrom, 2007). g eo lo gi a c ro at ic a 276 geologia croatica 74/3 km se from manita peć cave and ca. 8 km s from the modrič cave) was used instead. both stations share similar topographic location and climate properties, so no significant changes in data representativeness are expected. 4. results 4.1. spatio-temporal variations of the cave air co2 concentration spatial and temporal variations of modrič cave air cdc are presented in fig. 2 and the complete data set is provided in tab. 1a in the appendix. at the first measurement point m00 in front of the cave, during the period between march 2017 and march 2021 we recorded cdcs from 350 ppm to 590 ppm. cave air cdc of the main passage measured at points m11 and m22 varied between 412 ppm and 6868 ppm; similar to that in the left passage, values between 480 ppm and 7228 ppm were recorded at points t13, t14 and t15. meanwhile, along the right passage, at measurement points m31 and m32, the cdc range was from 994 ppm to >10,000 ppm (i.e it exceeded the measurement limit of instrument). spatio-temporal variations of cave air cdc in the manita peć cave between january 2018 and march 2021 are given in fig. 3 and in tab. a2 in the appendix. the first measurement point (mp 01) was ~100 m away from the cave entrance at the most exposed part of the mountain slope, at the lookout, and provides values of the outside cdc, while point mp 02 was at the very entrance of the cave, right in front of the gate bars with a cdc range of 339-664 ppm (fig. 4). the remaining measurement points (mp 03 – mp 09), which were distributed evenly along the descending channel, had cdc values ranging between 325 ppm and 1415 ppm. temporal variations of cdc in both caves are seasonal, with the highest values in summer/autumn, and the lowest during the winter/spring, which is the opposite of natural atmospheric cdc fluctuations (pearman & hyson, 1981). namely, due to the phytoplankton bloom and plant photosynthesis in the warmer part of figure 2. variation of co2 concentrations along a) the left passage (july 2018 march 2021) and b) the right passage (march 2017 march 2021) of the modrič cave. note that both plots contain the same values for the first three measurement points, i.e. exterior point m00 and main passages’ points m11 and m22. figure 3. variation of co2 concentration in the manita peć cave (january 2018 – march 2021). g eologia c roatica 277surić et al.: spatio-temporal variations of cave-air co2 concentrations in two croatian show caves: natural vs. anthropogenic controls the year, co2 is absorbed from the atmosphere, so the cdc in the northern hemisphere decreases, while in autumn decaying plants release their co2 back into the atmosphere, which along with elevated fossil fuel consumption leads to an atmospheric cdc increase. surprisingly, the cdc variations in the surface air in front of our studied caves at m00 and mp 01 do not follow that pattern. instead, they coincide with in-cave cdc variations, as demonstrated in fig. 4, showing the influence of the in-cave environment on the nearest surroundings. 4.2. visitor numbers and their impact on cave air co2 concentration the total annual numbers of visitors in the caves are given in figs. 5a and 5c, and the monthly distribution of the manita peć cave visitors is presented in fig. 5b. the highest annual values reached in 2017 and 2018 are due to the prolonged working hours (4 hours per day instead of 3 hours) of manita peć cave, and the sudden decrease of visitor numbers in both caves is a direct response to the covid-19 pandemic. measurements of cdc before and after groups of tourists were conducted in spring and summer season at the sites where the visitors pause for the sightseeing or explanations, and the results are given in table 1. during the spring season, the increase of cdc measured immediately after the groups was 14-22% and 20-28% for manita peć cave and modrič cave, respectively. however, due to the relatively low initial cdc, absolute values after the visitors are still within safety limits. high cdcs in the summer season remained after the visitors at similar levels, ~1250 ppm in manita peć cave and ~5100 ppm along the left passage of modrič cave. the exception was measurement point mp03 in manita peć cave with an increase of 66% (from 740 ppm to 1230 ppm), but due to its location near the entrance, the cdc probably quickly reduced to the previous values. 5. discussion distribution and variations of cave co2 are controlled by an interplay of different sources and sinks and their spatial and temporal evolution, which are in the case of modrič and manita peć caves, relatively simple. there are no underground rivers or geogenic sources of co2, and in-cave decomposition of organic matter does not play an important role, since there are no large defigure 4. variation of air co2 concentration in the vicinity of the cave entrances; measurement point m00 was several metres in front of the modrič cave, mp 01 was at the lookout ~100 m away from manita peć cave and mp 02 was at the very gate of the same cave. note the relatively invariant mp 01 values in relation to the covariance of m00 and mp 02. figure 5. number of visitors a) annually in manita peć cave (2005-2020); b) monthly distribution in manita peć cave, and c) annually in modrič cave (20122020). note the significantly different y-axes scales in a and c. sudden decrease of number of visitors in 2020 reflects the covid-19 pandemic. (sources: np paklenica for manita peć cave and m. buzov, pers. comm. for modrič cave). table 1. effect of groups of visitors on air co2 concentration (in ppm) measured before and immediately after the visitor groups in manita peć cave and in the left passage of the modrič cave, in spring and summer seasons. only locations with longer tourists’ residence time are considered. for measurement points, see fig. 1. modrič cave measurement point 6 april 2018 20 july 2018 before after before after m11 5169 5178 m22 588 705 5132 5172 t13 575 715 5068 5158 t14 594 761 5034 5044 manita peć cave measurement point 1 may 2018 1 august 2018 before after before after mp03 452 577 740 1230 mp04 524 600 1243 1246 mp05 505 614 1270 1257 mp06 512 607 1259 1267 mp07 510 602 1315 1317 mp08 502 612 1346 1313 g eo lo gi a c ro at ic a 278 geologia croatica 74/3 posits of organic matter such as guano. the main factors controlling cdc are transport of co2-rich air from the soil horizon and epikarst, along with co2 degassing from drip water, and its dilution by the external co2-poor air, i.e. cave ventilation (ek & gewelt, 1985). cave ventilation dynamics follow several patterns controlled predominantly by seasonal temperature variations, cave morphology, and potentially by anthropogenic co2-flux, while the ventilation itself is mainly triggered by differences between outside (tout) and cave air (tcave) temperatures (spötl et al., 2005; baldini et al., 2006), and wind (riechelmann et al., 2019; kukuljan et al., 2021). these particular features are discussed bellow. 5.1. impact of cave morphology and epikarst structure on spatial cdc variations substantial differences between the modrič and manita peć cave morphology are depicted in their cross sections (fig. 6). modrič cave is almost horizontal except for the small descent near the entrance, and a short ascent at the beginning of the right passage. although relatively similar in dimensions, the two passages differ by their accessibility. along the left passage during the winter time, there are only small variations of cdc, with values <100 ppm higher that those outside the cave (fig. 7a). similarly, cdc values are also relatively evenly distributed in the summer-autumn season (fig. 7b), which is likely caused by unobstructed movement of the air through the left passage due to its larger dimensions compared to the right one. in the right passage, cdcs are substantially higher both during the warm and cold seasons, and spatial variations are more pronounced. the entrance section of the right passage (after m22) is only slightly ascending, but obviously enough to prevent or at least mitigate the inflow of the cool outside air during the cold season. additionally, the more diverse morphology of the right passage with several smaller chambers connected by narrow corridors makes this passage more constrained. an abrupt increase in cdc occurs ca. 50 m inside the passage, which is in accordance with the findings of baldini et al. (2006) and milanolo & gabrovšek (2009) who generally recorded such sudden increases in cdc right after constrictions in their studied caves. there is another difference in the spatial distribution of cdc between the two passages in the modrič cave. the left one has evenly distributed either summer (higher) or winter (lower) cdc values throughout the whole passage, while in the right passage the cdc values increase towards the end (fig. 7). this partially reflects the structure of the overlying bedrock, which is apparently more fractured, and hence easily ventilated, due to the fault zone along the left passage. the sets of small stalactites and sodastraws in the second part of this passage additionally point to the matrix porosity (fairchild & baker, 2012) of that part of the cave and can be regarded as a macrofissural network cf. bourges et al. (2006), defined as fissures of less than 1 mm aperture which transfer both rainwater and co2-rich soil air towards the cave. conversely, the bedrock of the right passage is more compact, or maybe even sealed by the spelean carbonate which is also reflected in more homogenous drip rates, sometimes unresponsive to surface rain events (surić et al., 2018). the apparent differences of the atmospheric regimes in the relatively similar passages underline that the volume of the critical zone involved in the control of in-cave atmosphere is much larger than the volume of the underground chambers and includes also the voids of the surrounding karstified bedrock (bourges et al., 2006). on the other hand, the manita peć cave consists of one large descending chamber that begins with two relatively large openings (1.7×2.5 m and 1.3×2.0 m), and the height difference from the entrances to the lowest point of the cave is 35 m. in addition, heavily fractured overlying bedrock detected in some places by the immediate rain fracture-flow infiltration (surić et al., 2017), figure 6. cross section of modrič and manita peć caves with marked measurement points. figure 7. spatial distribution of cave air co2 concentration in modrič cave passages during the: a) winter season – measured 1 february 2021; b) summer season – measured 3 september 2019. g eologia c roatica 279surić et al.: spatio-temporal variations of cave-air co2 concentrations in two croatian show caves: natural vs. anthropogenic controls enables considerable air circulation via epikarst. given the fulfilled prerequisites for significant ventilation, the spatial variations of cdc remain relatively minimal, particularly during the winter when cold air descends into the cave and cdc values within the cave are practically equal to the external ones (fig. 8a). summer spatial cdc variations are also relatively small (the maximum recorded value was 1415 ppm), specifically when compared to those in modrič cave. for the summer co2 distribution, the vertical dimension of the cave plays the leading role, with the inflow of the outside air being obstructed by the cold and dense air trapped at the cave bottom. this phenomenon has already been identified in the manita peć cave by the pocket of cold air having a year-round stable temperature of 9.0 °c (1σ=0.4 °c), while the external mean annual air temperature (maat) in front of the cave was 13.7 °c (2014-2015) (surić et al., 2017). such a stable thermal stratification during warm periods in aerodynamically closed cold trap systems has been discussed in e.g. bourges et al. (2006), luetscher et al. (2008), milanolo & gabrovšek (2009) etc. 5.2. temporal controls of the cave air co2 concentration temporal variations of cdc given in tabs. a1 and a2 and presented in figs. 2 and 3 point to the strong seasonal mode in both studied caves. given the constant air cave temperature, during the warm season the cave air temperature is lower than outside, and during the cold season the situation is the opposite. correlation between δt (tout – tcave) and cdc implies that air temperature differences govern the air density gradients between the outside and cave air and also control air exchange i.e. ventilation (fairchild & baker, 2012). studies conducted in caves with a comparable temperature regime and morphology in germany (bunker cave; riechelmann et al., 2019), puerto rico (cueva larga; vieten et al., 2016) and bosnia and herzegovina (srednja bijambarska cave; milanolo & gabrovšek, 2009) revealed the same driving mechanism of seasonal cdc variations; that is ventilation driven by an air density gradient between external and cave air. such circulation is known as a chimney effect, usually ascribed to the caves with two or more entrances at different altitudes (fairchild & baker, 2012). during the summer, warm surface air enters the cave via an upper entrance, cools down and with increased density it descends and emerges at a lower entrance as cold cave air. in winter time, cold dense outside air inflows through the lower entrance, warms up and, because it is less dense, appears at the upper opening (spötl et al., 2005). despite the fact that our studied caves have only one passable entrance, the chimney effect can be attributed to them, particularly to the modrič cave since it has only 2-30 m overburden thickness of faulted and heavily fractured limestone bedrock, which practically acts as an upper entrance. therefore, we identified two ventilation regimes and associated cdc variation patterns: – summer: with tout>tcave – warm surface air on its way through the epikarst is enriched by co2, downdraft occurs and cool cave air flows outwards from the caves, as proven by measured elevated cdc in front of the caves (fig. 4). – winter: with tout<tcave – cool co2-poor outside air flows into the cave and decreases cdc within the caves, leading even to the complete equalization of cdc throughout the whole manita peć cave for seven months (fig. 3). variations of temperatures and cdcs shown in figs. 9 and 10 provide an insight into the periods of transition between tout>tcave and tout<tcave considered to be crucial for the behaviour of the cave cdc (liñán et al., 2018), additionally modulated with some site-specific features related to the geometry of the caves, wind etc. generally, such thermal convective instability (bourges et al., 2006) with changes in cave air cdc was argued to occur rapidly and at precisely the time when the difference in temperature between the surface and cave air reverses sign (frisia et al., 2011). however, in the postojna cave it was shown that reversal from updraft to downdraft airflow occurs even while tcave is more than 10 °c higher than tout (kukuljan et al., 2021). in the modrič cave, in autumn when tout drops below tcave the decreasing trend of the cdc closely follows that of the tout, apparently due to the strong inflow of the dense external co2-poor air into the cave. however, spring conversion displays an evident lag of the cdc peaks behind tout maximum (fig. 9). this might be because biological activity (the main driving mecha nism of the cdc increase) increases more slowly than the temperature, which is particularly the case with deciduous plants which take time to grow leaves in the spring. the highest cdcs (>10,000 ppm) were recorded during the late summer of 2019 which was the coolest summer between 2017–2020, but the longlasting warmth with above-average precipitation in july (cmhs, 2021) obviously triggered intensive biological activity inducing the cdc increase. the aforementioned impact of different morphology of the left and right passage in the modrič cave is also evident when considering temporal variations in cdc distribution. namely, the sudden drop in cdc values recorded in the left passage during the autumn/winter transition period (e.g. november and december 2018) with cdc values decreasing from >5000 ppm to 500-600 ppm (fig. 9 & tab. a1) coincides with the drop of the figure 8. spatial distribution of cave air co2 concentration in manita peć cave during the: a) winter season – measured on 1 february 2021; b) summer season – measured on 3 september 2019. g eo lo gi a c ro at ic a 280 geologia croatica 74/3 tout below tcave, which usually occurs during october and november and triggers the inflow of the co2-poor outside air into the cave. at the same time, the decrease of the cdc in the right passage is much smoother as values drop from ca. 5000-6000 ppm to 30004500 ppm owing to the right passage’s tight spots preventing the rapid inflow of cooler outside air, but also because of apparently more compact bedrock and therefore reduced outflow. the transition between higher summer and lower winter cdc values in the manita peć cave (fig. 10) is governed by both the chimney effect and the cold trap responsible for the cave’s site-specific temperature regime. the cold trap is present during most of the year, so tout remains below tcave only relatively briefly during the winter (december to february/march). still, the innermost part of the cave retains unchanged cdc until may/june when tout increases to approximately 15-17 °c (fig. 10). presumably, because of the large volume of that part of the cave (cave ceiling is ca. 30 m high), it takes a longer time for the cdc to increase. also, the surface above the cave is over 600 m a.s.l., so increased biological activity in the soil lags behind that on the surface above the modrič cave. 5.3. impact of specific meteorological events occasionally, ventilation can be further modulated, and more rapid changes in cdc values are expected during specific meteorological episodes such as strong winds (riechelmann et al., 2019; kukuljan et al., 2021) and intense precipitation events (bourges et al., 2020). modrič and manita peć caves have northwardand eastward-facing entrances, respectively, exposed to the north-eastern bora – a gusty downslope windstorm characteristic for the eastern adriatic coast (grisogono & figure 9. time series of the surface (tout) and cave air temperature (tcave) and air co2 concentration at m32 – the innermost measurement point within the right passage where the highest cdc values were recorded, never falling below 1450 ppm. surface temperature is compiled from the starigrad (1/2017-7/2018) and novigrad stations (8/2018-8/2020), equally distant from modrič cave. data for april 2020 are missing due to the covid-19 pandemic. figure 10. time series of the surface (tout) recorded in front of the manita peć cave, and air co2 concentration at mp09 the innermost measurement point where the highest cdc values were recorded. cave air temperature (tcave) is an average value recorded between 7/2012 and 7/2014. note the significantly shorter duration of tout < tcave than tout > tcave. data for october 2018 are missing due to device failure, for april 2020 due to the covid-19 pandemic, and for june 2020 due to the drowning of the innermost part by the extreme rainfall. g eologia c roatica 281surić et al.: spatio-temporal variations of cave-air co2 concentrations in two croatian show caves: natural vs. anthropogenic controls belušić, 2009). during the bora episodes, which are particularly frequent in march (e.g. ivančan-picek & vučetić, 1990; colucci & pucillo, 2010) (anecdotally, three in a row), chimney circulation is disturbed in the modrič cave and surface air is pushed into the caves through the fractured bedrock due to the pronounced barometric high. similar reversed airflow is recorded in the postojna cave during the strong ne wind with gusts of >10 m/s (kukuljan et al., 2021). if airflow is not measured, such events can be distinguished by sudden decreases of cave air relative humidity, as recorded in march 2013 in manita peć and two other adjacent caves (surić et al., 2017). an immediate lowering of cdc can be revealed by continuous daily measurement as it was conducted e.g. in bunker cave during the strong southern winds (riechelmann et al., 2019), while our monthly measurement registered only the slight decrease of cdc after the onset of the warm season increase (5/2017, 4/2018, 5/2019, 3/2020) (tab. a1). impact of the south-eastern scirocco wind was not perceived, but probably might be instrumentally measured, similar to the postojna cave where the southern wind increases the winter updraft (kukuljan et al., 2021). in fact, these reversal and/or amplifying effects can occur in all seasons, but the predominant chimney effect can be overridden only by the strongest wind gusts (kukuljan et al., 2021). this secondary wind-induced ventilation may have ramifications for speleothem record interpretation when it comes to dry and windy glacial periods in which summer high cdc could have been suppressed, enabling speleothem precipitation. an opposite effect, i.e. an increase of cdc, may be related to intense precipitation that increases groundwater infiltration in the cave, which in turn elevates the co2 concentration through degassing from the drip water (houillon et al., 2017; bourges et al., 2020). although two extreme rain events occurred during the monitoring period (daily precipitation of 229 mm on 11 sept 2017 and 151 mm on 5 jun 2020), increased cdc values were not observed during the monthly visit. this implies that short-term rain (and infiltration) events do not affect cdc on a monthly scale in terms of consequent growth cessation, particularly when site-specific settings of the aquifers are considered. stalagmate® drip logger data point to a wide range of flow regimes (baker et al., 1997), from an immediate response due to fracture flow in the manita peć cave (surić et al., 2017) to practically unresponsive homogenised drip rates in the right passage of the modrič cave (surić et al., 2018). 5.4. influence of visitors on cave cdc and/or the opposite impacts any human presence in the caves can elevate air temperature, relative humidity and dust content in the air, as well as disturb its chemical composition which can all potentially threaten speleothem formation. upon cessation of the use of open fire and acetylene lighting in show caves (in modrič cave it was part of an adventure offer until 2015), breathing remains the only direct human influence on the cave air chemical composition. in exhaled human breath, co2 concentration is ~20,000-58,000 ppm (byrnes et al., 1997), and in specific circumstances in the caves, it appears to serve as a high-concentration source of co2 (prelovšek et al., 2018). individual production, i.e. co2 exhalation rate, depends on a person’s age and physical activity. some estimated and calculated values are: 0.2-1.2 lco2 min-1 person-1 (dragovich & grose 1990), 0.39 ± 0.11 lco2 min-1 person-1 (faimon et al., 2006) and 0.35-0.45 lco2 min-1 person-1 (milanolo & gabrovšek, 2009). the contribution of co2 from human breathing (δcco2) can be calculated by the expression (1) (prelovšek et al., 2018): δcco2 = ja × t × nv / vest (1) where δcco2 is change of cdc due to the exhalation (in ‰), ja is co2 production (exhalation) rate (in lco2 min-1 person-1), t is the residence time of the visitor (in minutes), nv is number of visitors, and vest is estimated volume of the cave/passage (in m3). in the manita peć cave, with its relatively short working hours, in august there are only ~130 visitors per day (2020 not taken in account due to covid-19 pandemic), and with their average residence time of 30 minutes in the total cave volume of 67,510 m3, they contribute to the overall cdc with 12-26 ppm per day. seasonal peak attendance in the modrič cave is 30 visitors per day and their trip takes place in the left passage, roughly estimated at 10,000-13,000 m3 of total volume. during the 2-hour tour, their contribution to the natural cdc is approximated to 55-162 ppm, which is six times higher than in manita peć cave. both of these estimations are calculated with a theoretical absence of ventilation. a similar increase of 5.6 to 28 ppm per adultequiva lent person per hour was measured in the grotta di ernesto (frisia et al., 2011). our calculated values corroborate the measurements given in tab. 1 and reflect prudent management of both caves in the sense of environmental protection. an opposite effect, i.e. the impact of high cave air cdc on visitors, can be expected in summer since the high tourist seasons coincides with the period of the elevated naturally occurring co2 (figs. 2a, 3 and 5b). in the manita peć cave, the highest recorded cdc value of 1415 ppm has no influence on visitors, as that is around the level commonly reached indoors, but values that occur along the modrič cave tourist path are already 20-25 times higher than those of the outside atmosphere. luckily, cdc peaks are reached only in september, after the tourists’ peak in august. potentially harmful cdcs >10,000 ppm that can cause increased respiratory rate, respiratory acidosis, metabolic stress, increased brain blood flow and increased minute ventilation (azuma et al., 2018) have been recorded in the right passage which is only of scientific interest and not visited by tourists. however, there is an additional health risk in that part of the cave. it relates to the radioactive gas radon which is emitted from the deeper earth’s crust without any surface input. according to preliminary observation (sršen, 2019), given its good correlation with cdc, and dependence of its concentration exclusively on dilution with surface air, we may expect potentially dangerous values during the summer season in the right passage. 5.5. potential impact of long term natural and anthropogenic environmental changes to the surface on speleothem-based palaeoclimate interpretation contemporary vegetation cover that consists of scrubby mediterranean maquis-like plants has been subject to permanent natural, and more recent human-induced, changes that result in proor degradation of the soil horizon and plant density – the main source of co2 in our studied sites. on decadal to centennial scales, the earliest anthropogenic impact manifested by enhanced erosion due to deforestation can be detected in marine sediment from modrič bay back to 1715 cal bp, with maximum at 160-265 bp (hasan, 2017). velebit woodlands across the wider region experienced drastic changes, as they were overused during the 16th-17th c. not only by the venetians, habsburgs and otomans (štefanec, 2000), but also by the growing local population g eo lo gi a c ro at ic a 282 geologia croatica 74/3 (rukavina, 1990). this also coincided with the little ice age with increased demands for firewood (kužić, 1999). under the french government starting at 1805, and with ameliorated climate conditions, erosion and/or deforestation declined (hasan, 2017). organized reforestation began in the late 19th century (kaser, 1987) and was intensified during the ban on goat breeding in 1954-1982, but the recovery has been relatively slow. evident changes of vegetation cover on the decadal scale have been documented by aerial photography (fig. 11). bare karst scenery that dominated in 1959 and 1973 was partially changed by planned reforestation (recorded in 1989), followed by natural (and occasional anthropogenic) forestation during the last three decades. each of these soil or/and vegetation alterations might have left an imprint in co2-controlled speleothems growth rate. going farther back into the past, beyond human interference, climate changes at the centennial to millennial scale controlled environmental settings in terms of temperature and/or humidity variations and hence cave ventilation, which, in turn, forced or ceased speleothem precipitation. throughout the glacial periods, commonly regarded as cold, dry and windy, in ice-covered and some periglacial regions, speleothem deposition completely ceased (baker et al., 1995; lowe & walker, 1998). this was due to the lack or negligible input of pedogenic co2 into the karst system because of the absence of a soil cover (spötl et al., 2006; li et al., 2021). however, that was not the case in littoral croatia, as evidenced in currently submerged speleothems that precipitated during the last glacial maximum (surić & juračić, 2010), and particularly in speleothems from the manita peć cave where sufficient pedogenic co2 sustained karst processes, including speleothem deposition, throughout the last glacial cycle (surić et al., 2021). presumably, the possibility of growth cessation caused by a diminished gradient between pco2 figure 11. natural and anthropogenic environmental transformations on the surface above the modrič cave between 1959 and 2020. modrič cave plan is given in red. g eologia c roatica 283surić et al.: spatio-temporal variations of cave-air co2 concentrations in two croatian show caves: natural vs. anthropogenic controls in drip water and cave air was compensated by enhanced wind activity (wacha et al., 2013; durn et al., 2018; kovačić et al., 2013) which promotes cave ventilation (riechelmann et al., 2019). as for the past interglacials, likewise today, growth interruptions due to enhanced biological activity, elevated cdcs and hindered degassing have been possible in the modrič cave. given that the potential growth cessation occurs only seasonally, the winter signal may dominate in other speleothem climate-related properties and proxies driven by co2-flux, as well (genty et al., 2001; baldini et al., 2008; frisia et al., 2011). one such commonly used proxy is δ13c, which increases with vegetation decline related to climate deterioration, accompanied finally by the cessation of speleothem growth (frisia et al., 2011). in addition, cave ventilation forces degassing of co2 from dripwater, prior to any calcite precipitation onto the stalagmites (frisia et al., 2011). prior calcite precipitation leads to 13c-enrichment in the speleothems (fairchild & baker, 2012) during deposition within the cave atmosphere obviously favourable for their growth. these similar signals, but supported by opposite conditions, underscore the importance of a multiproxy approach to verify palaeoclimate interpretations. 6. conclusions we presented the results of multiyear monitoring of cdc in the modrič and manita peć show caves, which was conducted in order to identify spatio-temporal cdc variations, their controlling mechanisms and potential mutual influence and interrelationships between cave atmosphere and visitors. i) the main sources of co2 in both caves are plantand microbial-derived co2 produced in the soil horizon by root respiration and decay of organic matter that is transported downward, and in-cave co2 degassing of the dripping groundwater. underground streams are absent and co2 production by cave biota is considered negligible. the main sink for the cave air co2 is dilution with outside air due to the cave ventilation which is governed by air density differences derived from different air temperature, and by occasional wind-induced air flow. ii) general ventilation patterns are seasonal and mimic the chimney-type circulation with associated cdc variations: the winter mode includes inflow of cold, dense co2-poor outside air into the caves due to the tout < tcave, while in summer mode, warm surface co2-rich air enters into the caves during tout > tcave. the key events are abrupt transitions from tout > tcave to tout < tcave followed by a sudden cdc drop. occasionally, ne bora wind-induced air flow, as a secondary ventilation pattern, overprints the primary ventilation model, while the influence of wind-driven ventilation of the se scirocco was not noticed. iii) superimposed upon the ventilation driven by air density gradient are circulation effects controlled by cave geomorpho logy and epikarst architecture, so the similar seasonal ventilation patterns result in large differences between absolute cdc values in the inclined and spacious manita peć cave, and the horizontal and more confined modrič cave. moreover, within the same cave, the right and left modrič cave passages are ventilated differently due to the fractured fault zone of passable left passage (more ventilated) and more constrained right one (less ventilated). iv) although these caves are only 8 km apart, belong to the same type of climate (cfa) and vegetation zone (mediterranean), and spatio-temporal cdc variations within them are generally controlled by the same dynamic (seasonal) ventilation patterns, the magnitude of cdc variation appears to be site-specific. due to the dependence of calcite precipitation on cdc variation, careful selection of the samples for speleothem-based palaeoenvironmental studies is essential. in particular, the manita peć cave generally does not experience major co2 fluctuations, so neither deterioration by condensation corrosion of the already deposited calcite, nor growth inhibition due to the cdc fluctuations is expected. on the other hand, the very high summer-autumn co2 concentration within modrič cave could reduce co2 degassing from the dripwater and thus hamper calcite precipitation. v) due to the low number of visitors, anthropogenic impacts on cave cdc is negligible even in the confined modrič cave passages, when compared to the natural co2 input which is higher by two orders of magnitude. in the manita peć cave episodes with slightly elevated human-induced concentrations are occasional and temporary short-duration events, with insignificant contribution to the natural co2 content. vi) conversely, given the site-specific nature of cdc and known temporal patterns, cave management should maintain the same practice of short visits of small groups in manita peć cave and the left passage of modrič cave, while the right one should be avoided at least in late summer and during autumn. vii) elevated cdc values and similar preliminary results of radon measurements urge high-resolution (daily to hourly) monitoring of both parameters, measurement of velocity and the direction of air flow, along with collection of modern calcite to assess its precipitation in relation to the ventilation dynamics. acknowledgement we are grateful to the public institution natura jadera and paklenica national park executives and staff for their kind cooperation and support. marijan buzov, concessionaire of modrič cave, is acknowledged for long-term fruitful collaboration and field assistance. we also thank the croatian meteorological and hydrological service for providing climatological and meteorological data. special thanks go to ira sasowsky for language editing, as well as to mitja prelovšek and an anonymous reviewer for their constructive comments and suggestions. references action plan national park paklenica (2007), starigrad-paklenica. aguilar, j., brajković, d., crochet, j., mauch lenardić, j., michaux, j., mihevc, a. & sige, b. (2004): fossil-bearing fissure fillings of slovenia and croatia.– proceedings of the 12th international karstological school, classical karst: dating of cave sediments. karst research institute zrc sazu, postojna, slovenia. azuma, k., kagi, n., yanagi, u. & osawa, h. (2018): effects of low–level inhalation exposure to carbon dioxide in indoor environments: a short review on human health and psychomotor performance.– environ. int., 121, 51–56. doi: 10.1016/j.envint.2018.08.059 baker, a., smart, p.l. & edwards, l.r. (1995): palaeoclimate implications of mass spectrometric dating of a british flowstone.– geology, 23/4, 309–312. doi: 10.1130/0091-7613(1995)023<0309:piomsd>2.3.co;2 baker, a., barnes, w. & smart, p. (1997): variations in the discharge and organic matter content of stalagmite drip waters in lower cave, bristol.– hydrol. process., 11, 1541–1555. doi: 10.1002/(sici)1099-1085(199709)11:11<1541::aidhyp484>3.0.co;2-z baldini, j.u.l., baldini, l.m., mcdermott, f. & clipson, n. (2006): carbon dioxide sources, sinks, and spatial variability in shallow temperate zone caves: evidence from ballynamintra cave, ireland.– j. cave karst stud., 68, 4–11. baldini, j.u.l., mcdermott, f., hoffmann, d.l., richards, d.a. & clipson, n. (2008): very high-frequency and seasonal cave atmosphere pco2 variability: implications for stalagmite growth and oxygen isotope–based paleoclimate records.– earth planet. sci. lett., 272, 118–129. doi: 10.1016/j.epsl.2008.04.031 batiot-guilhe, c., seidel, j., jourde, h., hébrard, o. & bailly-comte, v. (2007): seasonal variations of co2 and 222rn in mediterranean sinkhole–spring (causse d’ aumelas, se france).– int. j. speleol., 36, 51–56. doi: 10.5038/1827806x.36.1.5 g eo lo gi a c ro at ic a 284 geologia croatica 74/3 benson, a., hoffmann, d.l., daura, j., sanz, m., rodrigues, f., souto, p., & zilhão, j. (2021): a speleothem record from portugal reveals phases of increased winter precipitation in western iberia during the holocene.– the holocene, 31/8, 1339–1350. doi: 10.1177/09596836211011666 bočić, n. & buzjak, n. (2018): neki novi rezultati mjerenja koncentracije co2 u odabranim špiljama u hrvatskoj [some new results of measuring co2 concentration in selected caves in croatia – in croatian].– zbornik sažetaka skupa speleologa hrvatske 2018. ur: paar, d., felić, m. zagrebački speleološki savez. bourges, f., genthon, p., mangin, a. & d’hulst, d. (2006): microclimates of l’aven d’orgnac and other french limestone caves (chauvet, esparros, marsoulas).– int. j. climatol., 26, 1651–1670. doi: 10.1002/joc.1327 bourges, f., genty, d., perrier, f., lartiges, b., régnier, e., françois, a. leplat, j., touron, s., bousta, f., massault, m., delmotte, m., dumoulin, j-p., girault, f., ramonet, m., chauveau, c. & rodrigues, p. (2020): hydrogeological control on carbon dioxide input into the atmosphere of the chauvet-pont d’arc cave.– sci. total environ., 716, 136844. doi: 10.1016/j.scitotenv.2020.136844 božičević, s. (1966): dvije krške jame s plinom (co2) [two karst pits with gas (co2) – in croatian].– geološki vjesnik, 20, 317–327. brantley, s., goldhaber, m. & ragnarsdóttir, k. (2007): crossing disciplines and scales to understand the critical zone.– elements, 3, 307–314. doi: 10.2113/ gselements.3.5.307 buzjak, n., paar, d. & radolić, v. (2010): utjecaj nadmorske visine na mikroklimu i koncentraciju radona u spiljama u širem području južnog velebita [influence of altitude on microclimate and radon concentration in caves in the wider area of southern velebit mountain – in croatian].– in: skup speleologa hrvatske povodom 110 godina speleološkog odsjeka “liburnija”: zbornik sažetaka. zadar: so, 33–33. byrnes, c.a., dinarevic, s., busst, c., bush, a. & shinebourne, e.a. (1997): is nitric oxide in exhaled air produced at airway or alveolar level?– eur. respir. j., 10, 1021–1025. doi: 10.1183/09031936.97.10051021 cmhs (2021): croatian meteorological and hydrological service. accessed on 23 april 2021. colucci, r.r. & pucillo, a. (2010): on the analysis of an extreme bora wind event over the northern adriatic sea.– in: 10th ems annual meeting, 10th european conference on applications of meteorology (ecam) abstracts, zürich, switzerland, sept. 13–17, vol. 7, 281. comas-bru, l., rehfeld, k., roesch, c., amirnezhad-mozhdehi, s., harrison, s.p., atsawawaranunt, k., ahmad, s.m., brahim, y.a., baker, a., bosomworth, m., breitenbach, s.f.m., burstyn, y., columbu, a., deininger, m., demény, a., dixon, b., fohlmeister, j., hatvani, i.g., hu, j., kaushal, n., kern, z., labuhn, i., lechleitner, f. a., lorrey, a., martrat, b., novello, v.f., oster, j., pérezmejías, c., scholz, d., scroxton, n., sinha, n., ward, b.m., warken, s. & zhang, h. (2020): sisalv2: a comprehensive speleothem isotope database with multiple age-depth models.– earth syst. sci. data, 12/4, 2579–2606. doi: 10.5194/essd-12-2579-2020 constantin, s., mirea, i.c., petculescu, a., arghir, r.a., măntoiu, d.ș., kenesz, m., robu, m. & moldovan, o.t. (2021): monitoring human impact in show caves. a study of four romanian caves.– sustainability, 13, 1619. doi: 10.3390/su13041619 cowan, b.d., osborne, m.c. & banner, j.l. (2013): temporal variability of cave-air co2 in central texas.– j. cave karst stud., 75, 38–50. doi: 10.4311/2011e s0246 czuppon, g., demény, a., leél-őssy, s., óvari, m., molnár, m., stieber, j., kiss, k., kármán, k., surányi, g. & haszpra, l. (2018): cave monitoring in the béke and baradla caves (northeastern hungary): implications for the conditions for the formation cave carbonates.– int. j. speleol., 47/1, 13–28. doi: 10.5038/1827-806x.47.1.2110. dragovich, d. & grose, j. (1990): impact of tourists on carbon dioxide levels at jenolan caves, australia: an examination of microclimatic constraints on tourist cave management.– geoforum, 21, 111–120. doi: 10.1016/0016-7185(90)90009u dreybrodt, w. (1999): chemical kinetics, speleothem growth and climate.– boreas, 28, 347–356. doi: 10.1111/j.1502-3885.1999.tb00224.x dublyanski, v.n. & dublyanski, y.v. (1998): the problem of condensation in karst studies.– j. cave karst stud., 60/1, 3–17. durn, g., rubinić, v., wacha, l., patekar, m., frechen, m., tsukamoto, s., tadej, n. & husnjak, s. (2018): polygenetic soil formation on late glacial loess on the susak island reflects paleo–environmental changes in the northern adriatic area.– quater. int., 494, 236–247. doi: 10.1016/j. quaint.2017.06.072 ek, c. & gewelt, m. (1985): carbon dioxide in cave atmospheres. new results in belgium and comparison with some other countries.– earth surf. proc. land., 10, 173–187. doi: 10.1002/esp.3290100209 faimon, j., štelcl, j. & sas, d. (2006): anthropogenic co2-flux into cave atmosphere and its environmental impact: a case study in the císarská cave (moravian karst, czech republic).– sci. total environ., 369, 231–245. doi: 10.1016/j.scitotenv.2006.04.006 fairchild, i.j. & baker, a. (2012): speleothem science: from process to past environments.– wiley–blackwell. chichester. doi: 10.1002/9781444361094 frisia, s., fairchild, i.j., fohlmeister, j., miorandi, r., spötl, c. & borsato, a. (2011): carbon mass–balance modelling and carbon isotope exchange processes in dynamic caves.– geochim. cosmochim. ac., 75/2, 380–400. doi: 10.1016/j.gca.2010.10.021 gabrovšek, f., dreybrodt, w. & perne, m. (2010): physics of condensation corrosion in caves.– in: andreo, b., carrasco, f., durán, j. & lamoreaux, j. (eds.). advances in research in karst media.– environ. earth sci., springer, berlin, heidelberg. doi: 10.1007/978-3-642-12486-0_75 genty, d., baker, a. & vokal, b. (2001): intra–and inter–annual growth rate of modern stalagmites.– chem. geol., 176/1–4, 191–212. doi: 10.1016/s00092541(00)00399-5 gregorič, a., vaupotič, j. & gabrovšek, f. (2013): reasons for large fluctuation of radon and co2 levels in a dead-end passage of a karst cave (postojna cave, slovenia).– nat. hazards earth syst. sci., 13, 287–297. doi: 10.5194/ nhess -13-287-2013 grisogono, b. & belušić, d. (2009): a review of recent advances in understanding the mesoand microscale properties of the severe bora wind.– tellus a, 61, 1–16. doi: 10.1111/j.1600-0870.2008.00369.x hasan, o. (2017): paleookolišna rekonstrukcija slivova karinskoga mora, novigradskoga mora i velebitskog kanala tijekom holocena [holocene palaeo-environmental reconstruction of the karin sea, novigrad sea and velebit channel catchments– in croatian].– unpubl. phd theses, university of zagreb, faculty of mining geology and petroleum engineering, rudarsko-geološko-naftni fakultet. houillon, n., lastennet, r., denis, a., malaurent, p., minvielle, s. & peyraube, n. (2017): assessing cave internal aerology in understanding carbon dioxide (co2) dynamics: implications on calcite mass variation on the wall of lascaux cave (france).– environ. earth sci., 76, 170. doi: 10.1007/s12665-0176498-8. ilo (2021): international labour organization, international chemical safety cards, https://www.ilo.org/dyn/icsc/showcard.home. accessed on 23 april 2021. ivančan-picek, b. & vučetić, v. (1990): bora on the northern adriatic coast during the alpex sop, 20–25 march 1982.– hrvatski meteorološki časopis, 25, 1–12. kaser, k. (1987): uništenje šuma na obalnom kraškom području hrvatske vojne krajine u prvoj polovici 18. stoljeća. njegovi demografski, privredni i socijalni uzroci [destruction of forests in the coastal karst area of the croatian military border in the first half of the 18th century. its demographic, economic and social causes – in croatian].– in: kampuš, i. (ed.), historijski zbornik 40. savez povijesnih društava hrvatske, zagreb, 121–137. kovačić, m., pavelić, d., vlahović, i., marković, f., wacha, l., kampić, š., rončević, s. & drempetić, d. (2018): pleistocene alluvial and aeolian deposits with tephra on the island of lopud (eastern midadriatic, croatia): provenance, wind regime, and climate controls.– quater. int., 494, 92–104. doi: 10.1016/j.quaint.2017.11.054 kuhta, m., božičević, s., kapelj, s. & miko, s. (1999): studija zaštite i korištenja vrijednih prirodnih cjelina modrič špilje i njene okoline [study of protection and use of valuable natural units of modrič cave and its surroundings – in croatian].– archives of the croatian geological survey, 68. kuhta, k. (2010): špilja manita peć, np paklenica – izvještaj o topografskom snimanju i uspostavi praćenja kriptoklimatskih parametara [manita peć cave, np paklenica – report on topographic survey and establishing of the cryptoclimatological parameters monitoring – in croatian].– hidrogeos d.o.o., zagreb. kukuljan, l., gabrovšek, f., covington, m.d. & johnston v.e. (2021): co2 dynamics and heterogeneity in a cave atmosphere: role of ventilation patterns and airflow pathways.– theor. appl. climatol. doi: 10.1007/s00704-021-03722-w kužić, k. (1999). zabilježbe o “malom ledenom dobu” i njegovim posljedicama u hrvatskim krajevima. [notes on “little ice age” and its consequences for the croatian lands – in croatian].– povijesni prilozi, 18/18, 373–404. li, h., spötl, c. & cheng, h. (2021): a high-resolution speleothem proxy record of the late glacial in the european alps: extending the nalps19 record until the beginning of the holocene.– j. quaternary sci., 36, 29–39. doi: 10.1002/jqs.3255 liñán, c., vadillo, i. & carrasco, f. (2008): carbon dioxide concentration in air within the nerja cave (malaga, andalusia, spain).– int. j. speleol., 37/2, 99–106. doi: 10.5038/1827-806x.37.2.2 liñán, c., del rosal, y., carrasco, f., vadillo, i., benavente, j. & ojeda, l. (2018): highlighting the importance of transitional ventilation regimes in the management of mediterranean show caves (nerja-pintada system, southern spain).– sci. total environ., 631–632, 1268–1278. doi: 10.1016/j.scitotenv.2018.02.304 lowe, j.j. & walker, m.j.c. (1998): reconstructing quaternary environments. 2nd ed.– longman, essex, 446. g eologia c roatica 285surić et al.: spatio-temporal variations of cave-air co2 concentrations in two croatian show caves: natural vs. anthropogenic controls luetscher, m., lismonde, b. & jeannin, p.-y. (2008): heat exchanges in the heterothermic zone of a karst system: monlesi cave, swiss jura mountains.– j. geophys. res., 113. doi: 10.1029/2007jf000892 malez, m. (1954): pećine otoka iža i ugljana [caves of the islands iž and pašman – in croatian].– speleolog, 2/1, 1–16. malez, m. (1987): kvartarna fauna vertebrata iz modriča pećine kod rovanjske (hrvatska) [quaternary vertebrate fauna from modrič cave (croatia) near rovanjska – in croatian].– rad 431: razred za prirodne znanosti (jazu do 1991.), 22/431, 141–154. milanolo, s. & gabrovšek, f. (2009): analysis of carbon dioxide variations in the atmosphere of srednja bijambarska cave, bosnia and herzegovina.– bound.lay. meteorol., 131, 479–493. doi: 10.1007/s10546-009-9375-5 mccabe, g.j. & markstrom, s.l. (2007): a monthly water-balance model driven by a graphical user interface.– u.s. geological survey, open-file report, 2007–1088. miko, s., kuhta, m. & kapelj, s. (2001): bat guano influence on the geochemistry of cave sediments from modrič cave; croatia.– in: 13th international congress of speleology: speleology in the third millennium: sustainable development of karst environments, brasilia. miko, s., kuhta, m. & kapelj, s. (2002): environmental baseline geochemistry of sediments and percolating waters in the modrič cave, croatia.– acta carsologica, 31/1, 135–149. doi: 10.3986/ac.v31i1.409 noaa (2021): national oceanic and atmospheric administration, global monitoring laboratory, https://www.esrl.noaa.gov/gmd/ccgg/trends/global.html. accessed on 27 august 2021. pearman, g.i. & hyson, p. (1981): the annual variation of atmospheric co2 concentration observed in the northern hemisphere.– j. geophys. res., 86/c10, 9839-9843. doi:10.1029/jc086ic10p09839 prelovšek, m., šebela, s. & turk, j. (2018). carbon dioxide in postojna cave (slovenia): spatial distribution, seasonal dynamics and evaluation of plausible sources and sinks.– environ. earth sci., 77/7. doi: 10.1007/s12665-018-7459-6 radolić, v., miklavčić, i., poje, m., stanić, d. & vuković, b. (2012): radon levels in manita peć cave (croatian np paklenica) and assessment of effective dose received by visitors and tourist guides.– in: irpa13 full paper–13th international congress of the international radiation protection association, p10, 1056, 1–10. regattieri, e., zanchetta, g., isola, i., zanella, e., drysdale, r.n., hellstrom, j.c., zerboni, a., dallai, l., tema, e., lanci, l., costa, e. & magrì, f. (2019): holocene critical zone dynamics in an alpine catchment inferred from a speleothem multiproxy record: disentangling climate and human influences.– sci. rep., 9, 1–9. doi: 10.1038/s41598-019-53583-7 riechelmann, s., breitenbach, s., schröder-ritzrau, a., mangini, a., & immenhauser, a. (2019): ventilation and cave air pco2 in the bunkeremst cave system (nw germany): implications for speleothem proxy data.– j. cave karst stud., 81, 98–112. doi:10.4311/2018es0110 rudzka, d., mcdermott, f. & surić, m. (2012): a late holocene climate record in stalagmites from modrič cave (croatia).– j. quaternary sci., 27/6, 585–596. doi: 10.1002/jqs.2550 rukavina, a. (1990): još žive velebitske šume. [forests of velebit still live – in croatian] – senjski zbornik, 17/1, 281–290. spötl, c., fairchild, i.j. & tooth, a.f. (2005): cave air control on dripwater geochemistry, obir caves (austria): implications for speleothem deposition in dynamically ventilated caves.– geochim. cosmochim. ac., 69/10, 2451–2468. doi: 10.1016/j.gca.2004.12.009 spötl, c., mangini, a., & richards, d.a. (2006): chronology and paleoenvironment of marine isotope stage 3 from two high-elevation speleothems, austrian alps.– quaternary sci. rev., 25/9–10, 1127–1136. doi: 10.1016/j.quascirev.2005.10.006 sršen, l. (2019): monitoring okolišnih uvjeta špilje modrič [monitoring of the cave environmental settings in modrič cave – in croatian].– unpubl. graduate thesis, university of zadar, 44. surić, m. (2018): speleothem-based quaternary research in croatian karst – a review.– quatern. int., 490, 113–122. doi: 10.1016/j.quaint.2018.04.043 surić, m. & juračić, m., (2010): late pleistocene – holocene environmental changes – records from submerged speleothems along the eastern adriatic coast (croatia).– geol. croat., 63/2. doi: 104154/gc.2010.13 surić, m., roller-lutz, z., mandić, m., krajcar bronić, i. & juračić, m. (2010): modern c, o, and h isotope composition of speleothem and dripwater from modrič cave, eastern adriatic coast (croatia).– int. j. speleol., 39, 91–97. doi: 10.5038/1827-806x.39.2.4 surić, m., lončarić, r., lončar, n., buzjak, n., bajo, p. & drysdale, r.n. (2017): isotopic characterization of cave environments at varying altitudes on the eastern adriatic coast (croatia)–implications for future speleothem-based studies.– j. hydrol., 545, 367–380. doi: 10.5038/1827-806x.39.2.4 surić, m., czuppon, g., lončarić, r., bočić, n., lončar, n., bajo, p. & drysdale, r.n. (2020): stable isotope hydrology of cave groundwater and its relevance for speleothem-based paleoenvironmental reconstruction in croatia.– water, 12, 2386. doi: 10.3390/w12092386 surić, m., bajo, p., lončarić, r., lončar, n., drysdale, r., hellstrom, j. & hua, q. (2021): speleothem records of the hydroclimate variability throughout the last glacial cycle from manita peć cave (velebit mountain, croatia). geosciences, 11/8, 347, 21 doi:10.3390/geosciences11080347 štefanec, n. (2000): trgovina drvetom na triplex confiniumu ili kako izvući novac iz senjskih šuma (1600-1630)? [wood trade on the triplex confinium or how to extract money from senj woodlands (1600-1630)? – in croatian].– in: proceedings, triplex confinium (1500.-1800.): ekohistorija. zadar, croatia, 337–365. thornthwaite, c.w. (1948): an approach toward a rational classification of climate.– geogr. rev., 38, 55–94. doi: 10.2307/210739 vieten, r., winter, a., warken, s.f., schrӧder-ritzrau, a., miller, t.e. & scholz, d. (2016): seasonal temperature variations controlling cave ventilation processes in cueva larga, puerto rico.– int. j. speleol., 45, 259–273. doi: 10.5038/1827-806x.45.3.1983 wacha, l., galović, l., koloszár, l., magyari, a., chikán, g. & marsi, i. (2013): the chronology of the šarengrad ii loess-palaeosol section (eastern croatia).– geol. croat., 66/3, 191–203. doi: 10.4154/gc.2013.18 g eo lo gi a c ro at ic a 286 geologia croatica 74/3 table a1. modrič cave air co2 concentration (in ppm) measured during the 2017-2021 period. april 2020 data are missing due to the covid-19 pandemic lockdown. for the measurement points, reader is referred to the fig. 7. main passage left passage right passage m00 m11 m22 t13 t14 t15 m31 m32 3 mar 2017 385 490 441 994 1475 4 apr 2017 385 427 528 1107 1580 2 may 2017 393 412 458 1067 1666 2 jun 2017 393 2115 2244 2536 2558 4 jul 2017 380 3600 4450 4850 4900 31 jul 2017 5155 5110 6517 6600 5 sep 2017 386 4800 4900 7070 7620 3 oct 2017 373 415 2813 5138 6145 31 oct 2017 383 388 1358 4180 4892 5 dec 2017 387 382 411 2060 3522 4 jan 2018 366 378 416 1028 1858 30 jan 208 438 454 485 1161 1769 1 mar 2018 459 606 504 1640 2153 6 apr 2018 418 492 545 1230 1915 1 may 2018 534 1886 1940 2278 2434 1 jun 2018 475 3081 3247 3879 3903 5 jul 2018 466 4772 4812 4713 4645 4752 7058 7228 1 aug 2018 487 5605 5620 5459 5432 5576 8810 8805 7 sep 2018 498 5723 6273 5781 5738 5871 8874 9386 2 oct 2018 388 5286 6485 8441 7831 6955 8215 9213 2 nov 2018 350 4252 4635 5200 5310 5293 4995 5812 4 dec 2018 458 614 521 554 551 1252 3095 4404 4 jan 2019 425 462 496 529 504 572 1657 2247 31 jan 2019 433 548 506 480 493 559 1447 2251 5 mar 2019 434 463 491 501 498 580 1245 1880 2 apr 2019 436 481 647 702 754 829 1820 2317 2 may 2019 440 461 525 540 544 640 1269 1940 31 may 2019 444 1170 1548 1808 2036 2098 2505 2613 2 jul 2019 520 3817 3846 3818 3849 3889 6195 6250 1 aug 2019 590 5313 5276 5214 5149 5211 8263 8550 3 sep 2019 422 6565 6868 6556 6533 7228 >10000>10000 1 oct 2019 482 6702 6731 6709 6636 6680 9614 >10000 5 nov 2019 564 3877 4220 5377 5752 5789 5314 6310 3 dec 2019 418 510 627 715 711 944 3104 4015 3 jan 2020 454 480 509 533 525 610 1358 2226 6 feb 2020 455 465 506 517 497 612 1617 2200 3 mar 2020 427 456 554 500 504 551 1293 1795 1 apr 2020 5 may 2020 439 513 705 759 900 1174 1590 2149 5 jun 2020 513 2755 2845 3030 3095 3150 3689 3924 30 jun 2020 584 4242 4234 4224 4212 4206 5420 5473 3 aug 2020 473 5495 5635 5317 5300 5481 8750 8867 1 sep 2020 477 2700 6070 6015 5960 6028 9790 >10000 1 oct 2020 574 1128 1680 2730 3100 3190 4670 6763 3 nov 2020 468 500 592 636 665 930 2976 4005 4 dec 2020 440 475 571 562 560 649 1698 3052 8 jan 2021 441 525 504 518 512 584 1425 2197 1 feb 2021 448 467 517 505 512 580 1243 1783 3 mar 2021 476 491 537 557 548 601 1419 2064 table a2. manita peć cave air co2 concentration (in ppm) measured during the 2018-2021 period. april 2020 data are missing due to the covid-19 pandemic lockdown. for the measurement points, reader is referred to the fig. 8. mp 01 mp 02 mp 03 mp 04 mp 05 mp 06 mp 07 mp 08 mp 09 4 jan 2018 325 339 325 351 348 400 397 398 421 30 jan 2018 414 411 404 441 444 407 464 414 413 1 mar 2018 354 373 412 411 422 412 413 415 415 6 apr 2018 391 387 400 414 415 422 414 415 441 1 may 2018 378 380 452 524 505 512 510 502 551 1 jun 2018 463 535 693 814 825 812 816 821 845 5 jul 2018 422 497 684 855 900 903 920 911 924 1 aug 2018 430 599 740 1243 1270 1259 1315 1346 1387 7 sep 2018 426 501 563 1166 1173 1170 1212 1198 1226 2 oct 2018 397 612 824 851 753 655 745 650 2 nov 2018 382 400 432 585 588 578 586 595 604 4 dec 2018 380 400 418 457 411 419 428 412 416 4 jan 2019 377 381 394 401 424 421 412 419 450 31 jan 2019 411 405 395 407 405 406 402 409 417 5 mar 2019 395 402 404 412 418 414 415 418 435 2 apr 2019 402 401 407 428 426 429 431 427 429 2 may 2019 413 407 411 435 465 469 471 466 476 31 may 2019 383 409 430 515 527 523 525 523 538 2 jul 2019 404 406 657 897 914 917 946 933 925 1 aug 2019 389 493 884 1185 1196 1179 1186 1210 1237 3 sep 2019 379 399 423 1048 1335 1323 1338 1415 1410 1 oct 2019 402 465 600 923 979 978 979 990 988 5 nov 2019 418 664 410 722 747 747 747 767 770 3 dec 2019 402 414 407 414 407 402 424 415 472 3 jan 2020 422 439 426 425 428 435 427 427 418 6 feb 2020 413 416 435 445 420 421 408 407 460 3 mar 2020 401 417 408 410 424 422 418 426 424 1 apr 2020 5 may 2020 405 405 419 428 409 420 428 435 442 6 jun 2020 448 422 437 488 513 514 505 519 30 jun 2020 392 435 616 738 738 762 758 746 778 3 aug 2020 397 422 718 1054 1076 1072 1127 1137 1152 1 sep 2020 394 424 576 1164 1140 1137 1142 1198 1210 1 oct 2020 415 436 458 696 706 712 719 734 740 3 nov 2020 434 428 436 500 533 530 535 539 554 4 dec 2020 416 407 435 434 431 420 413 416 438 8 jan 2021 397 416 425 434 434 433 434 428 433 1 feb 2021 432 441 405 424 431 431 430 435 463 3 mar 2021 420 427 450 444 446 448 448 447 458 appendix 2020 | 73/3 | 197–209 | 9 figs. | 2 tabs. | 1 app. www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction čukaru peki is a copper-gold ore deposit, discovered in 2012 by rakita exploration, 5km south of the mining town of bor in eastern serbia (jelenković, 2014). banješević & large (2014) state that this ore deposit can be genetically classified as a high-sulphidation epithermal and porphyry copper-gold deposit. this ore deposit belongs to the bor metallogenic zone, which is spatially and genetically related to the timok magmatic complex (janković, 1990). this complex is around 85 km long. it is elongated in an approximate n-s direction and stretches from the town of majdanpek in the north to tupiznica mountain in the south. it is part of the eastern segment of the cretaceous magmatic and metallogenic arc named the apuseni-banat-timoksrednogorje belt, which was formed during the closure of the neotethyan ocean (e.g., neubauer, 2002; gallhofer et al., 2015). magmatism in the timok complex lasted for around 10 ma, beginning in the upper turonian and ending in the upper campanian (clark & ullrich, 2004; kolb et al., 2013). however, it is generally accepted that most porphyry and epithermal ore deposits in this complex were formed in a considerably shorter period from 90 ma until 85 ma (jelenković et al., 2016, banješević et al., 2019). a simplified geological map of the timok magmatic complex with the locations of major ore deposits is illustrated in fig.1. mineralization at čukaru peki is located near the villages of brestovac and metovnica at depths between 400 >2000 m below the surface. it is hosted by altered upper cretaceous volcanic and volcaniclastic rocks named as the lower andesite by rakita exploration. they are overlain by a relatively unaltered andesitic unit, which varies in thickness from a few metres up to approximately 50 m; this volcanic unit is named the upper andesite. the fluid evolution of the čukaru peki cu-au porphyry system (east serbia) inferred from a fluid inclusion study velojić miloš, jelenković rade and cvetković vladica university of belgrade, faculty of mining and geology, đušina 7, 11 000 belgrade, serbia doi: 10.4154/gc.2020.14 abstract čukaru peki is a recently discovered copper-gold deposit in the bor metallogenic zone in east serbia. three types of mineralization can be distinguished in this ore deposit: porphyry, highsulphidation, and transitional epithermal type. this research was focused on fluid inclusion analysis of genetically different veins from the porphyry and the transitional zones of čukaru peki with an aim of better understanding the fluid evolution and mineralization processes in this system. seven types of veins were identified in the porphyry zone of čukaru peki and four of these veins contained transparent minerals which were suitable for fluid inclusion analysis. eight types of inclusion assemblages were distinguished in these veins: type 1 – primary inclusions with homogenization temperatures above 550°c and high salinity, type 2a – scattered polyphase inclusions with two salt crystals, type 2b-polyphase inclusions with two salt crystals in crystal growth zones, type 3 – brine inclusions with one salt crystal in crystal growth zones, type 4 – vapourrich inclusions, type 5 – primary inclusions in anhydrite, and types 6 and 7 – secondary lowtemperature inclusions this research suggests that saline fluids (30–40% wt.% nacl eq.) were the most important ones for the formation of porphyry-type mineralization and that the mineralization was formed at temperatures between 350 and 450°c and pressures between 100 and 500 bars. the epithermal stage was characterized by cooler low-salinity fluids with temperatures between 150-350°c, and salinity between 0 and 7 wt.% nacl eq. upper andesite unit is covered by a westwardly dipping upper cretaceous sedimentary sequence of marls, sandstones, and conglomerates. the entire volcano-sedimentary succession is unconformably overlain by miocene conglomerates and sandstones. the miocene sediments dip at a low angle to the east and their thickness varies from 200 400 m in the čukaru peki area. (banješević et al., 2019). to date, there have been a few fluid inclusion studies on samples from the bor metallogenic zone. strashimirov (1997) conducted fluid inclusion microthermonetry analysis on quartz samples from the nearby majdanpek porphyry deposit and concluded that the hydrothermal processes started in this system at temperatures higher than 580°c, which was followed by separation of high-salinity brines and low-salinity vapour within a temperature range of 550-450°c. it was also determined that the boiling of fluids has continued with decreasing temperature to about 400°c, when the hydrothermal system was opened. this led to the increase in influence of meteoric water and a decrease in temperature and salinity, which propagated the precipitation of ore minerals. later, koželj (2002) performed fluid inclusion studies on quartz, anhydrite and barite from the bor epithermal zone and recognized the activity of medium-temperature fluids (150250°c) with salinities of 2-14 wt.% nacl eq. and low-temperature fluids (130-220°c) with low salinities (< 5% wt.% nacl eq.). also, bailly et al. (2002) performed infrared microthermometry on opaque minerals (enargite and sphalerite) from the bor epithermal zone and concluded that the fluids had temperatures in the range of 163-240°c and salinities ranging between 4.65 and 8.41 wt.% nacl eq. here, we report and discuss the new results obtained by conventional petrography and microthermometry in samples from čukaru peki. this research is aimed at better constraining the article history: manuscript received april 15, 2020 revised manuscript accepted september 23, 2020 available online october 23, 2020 keywords: bor metallogenic zone, timok magmatic complex, fluid inclusions, porphyry cu deposit, massive sulphides, brines, fluid boiling g eo lo gi a c ro at ic a geologia croatica 73/3198 physico-chemical conditions that prevailed during the evolution of ore fluids at čukaru peki and illuminating the processes that led to the formation of this ore deposit. 2. geology of the deposit a simplified geological map of čukaru peki area with the locations of the studied drillholes is shown in fig. 2 and a simplified cross-section through the čukaru peki ore deposit showing zones of different types of mineralization is illustrated in fig. 3. according to jelenković et al. (2016) three major types of mineralization occur at čukaru peki as follows: 1) high sulphidation type – with a copper and gold-rich massive-sulphide ore body, which is roughly ellipsoid-shaped, with a horizontal area of 300x300m veins and a vertical length of 500-600 metres. the upper part of this ore body forms a rich apical zone, with more than 9% cu. going from the apical zone downward, the type of mineralization gradually changes to veins, disseminations and hydrothermal breccias. high sulphidation mineralization forms a zone, defined by intense alteration of the host rocks and pyritization at depths from 400 m to around 1000 m below the surface. the predominant sulphide minerals are covellite, pyrite, and enargite. the dominant alteration in this zone is advanced argillic (with quartz, alunite and dickite). there are several different types of hydrothermal breccias in the high sulphidation zone, but most ore-bearing breccias have fine-grained pyrite as fragments, with covellite, quartz or enargite in the matrix. the main copper-bearing minerals in the high-sulphidation zone are covellite and enargite, while recent measurements have shown that most of the gold in this zone is precipitated in the form of submicroscopic invisible gold in copper-bearing pyrite. (velojic & erlandsson, 2019) 2) transitional epithermal type located between the porphyry and high sulphidation zones. in this type, epithermal covellite and enargite replace the primary sulphide (chalcopyrite) from porphyry mineralization. most common veins in this zone are gypsum-, anhydrite-, and calcite veins, while the most common alteration is argillic (with kaolinite and/or montmorillonite). 3) porphyry type – mostly hosted in diorite porphyries and overlying andesites at depths below 1000 m from the surface. mineralization is mostly hosted by anhydrite and quartz veins figure 1. a simplified geological map of the timok magmatic complex showing the location of the čukaru peki cu-au deposit. legend: 1. bor clastites, 2. vrbovac reef, 3. boljevac latite, 4. valja strž plutonite, 5. osnić basaltic andesite and ježevica andesite, 6. metovnica epiclastite, 7. oštrelj sediments, 8. timok andesite, 9. lenovac clastites, 10. tmc basement rocks, 11. neogene and quaternary sediments, 12. porphyry cu-au and high sulphidation epithermal cu-au mineralization, 13. porphyry cu-au deposit. (modified from jelenković et al., 2016) g eologia c roatica velojić et al.: fluid evolution of the čukaru peki cu-au porphyry system (east serbia) inferred from a fluid inclusion study 199 and the main ore minerals are chalcopyrite, pyrite, bornite, magnetite, and pyrrhotite, whereas the main alteration style is potassic (with k-feldspar and biotite). the main copper-bearing mineral in this zone is chalcopyrite, while gold is mostly precipitated as small grains of native gold and electrum in quartz veins. the types of veins in the porphyry zone of čukaru peki generally fit into the classification scheme of veins in porphyry deposits described in sillitoe (2010). different types of veins in the porphyry zone of čukaru peki are illustrated in fig. 4, while the paragenetic sequence is illustrated in table 1. the assumed chronological order of the precipitation of veins at čukaru peki, based on the cross-cutting relationships of the veins, is as follows: 1) quartz a veins. (fig. 4a). wiggly thin quartz veins in early diorite porphyries. these veins do not contain ore mineralization. 2) quartz b veins. (fig. 4a). they are stockwork quartz veins with chalcopyrite bands in the middle parts, commonly present in early diorite porphyries and the overlying andesite. the main ore mineral is chalcopyrite, whereas bornite and pyrite are subordinate. 3) pyrite d veins (fig. 4b). these veins are composed of relatively coarse-grained aggregates of pyrite accompanied by smaller amounts of chalcopyrite, bornite and rutile. 4) magnetite m veins (fig. 4c). they always occur in deeper parts of the porphyry system. the main minerals in these veins are magnetite and hematite, accompanied by subordinate pyrite, pyrrhotite and chalcopyrite. figure 2. simplified geological map of the čukaru peki area with projected contours of high sulphidation and porphyry zones, major faults and sampled drill holes, modified from ni 43-101 preliminary economic assessment of the čukaru peki upper zone deposit, 2016. figure 3. simplified cross-sections through the čukaru peki ore deposit, modeled in leapfrog software, showing zones with different types of mineralization. legend: 1lower andesites; 2diorite porphyries; 3upper andesites; 4upper cretaceous marl; 5upper cretaceous clastics (bor conglomerates) 6cenozoic sediments. g eo lo gi a c ro at ic a geologia croatica 73/3200 5) purple anhydrite veins. (fig. 4d). these veins are very common in the porphyry zone and in the transitional epithermal zone. they contain pyrite as the main mineral, with smaller amounts of chalcopyrite and bornite or covellite and chalcocite, depending on the position in the system. 6) sulphide veins. (fig. 4c and fig. 4d ) these veins are also quite common in the porphyry zone and in the transitional porphyry-epithermal zone. the main ore minerals in these veins are pyrite and covellite, while the main gangue minerals are anhydrite and alteration clay (probably kaolinite). the main distinguishing feature of these veins is that they commonly contain covellite and crosscut all of the previous vein types. 7) orange anhydrite veins. (fig. 4e). they are late veins, which do not contain ore minerals, and as such, they are easily distinguished from the purple anhydrite veins. 3. samples and methods the high-sulphidation zone of čukaru peki does not contain transparent minerals suitable for conventional fluid inclusion analysis since most of the gangue minerals present are too finegrained to be studied (e.g. bodnar et al., 2014). some sulphide minerals, including pyrite and enargite, could be used for infrared fluid inclusions analysis, which has already been applied on samples from this metallogenic zone (bailly et al., 2002). the current research focuses on veins with transparent minerals from porphyry and transitional porphyry-epithermal zones. samples for analysis were selected from relatively coarsegrained quartz a and b veins, purple anhydrite veins and orange anhydrite veins. only one of the analyzed samples (cp069) was taken from the transition porphyry-epithermal zone, whereas all of the other samples were taken from the porphyry zone. transmitted-light petrography was performed on 12 doublepolished sections from 4 drill holes from the different zones of čukaru peki: fmtc1327, fmtc1328, fmtc1330 and tc160125. a total of 106 separate inclusions were measured during this research. all microthermometric measurements were performed in the fluid inclusion laboratory at the faculty of mining and geology, belgrade. measurements were carried out on a thmsg600 heating stage connected to an olympus bx51 microscope. the maximum heating temperature of inclusions on this device is 600°c and some of the analyzed inclusions did not reach total homogenization below this temperature. the primary co2 standard wrect-006160 was used for calibration. pvtx properties (salinity, pressure, density) of measured fluid inclusions were calculated using hokieflincs-h20nacl excel spreadsheet (steele-macinnis et al., 2012), based on the total homogenization temperature of the inclusions and ice melting temperatures (for unsaturated inclusions) or salt dissolution temperatures (for saturated inclusions with one or more salt crystals). salinities of brines were calculated by halite dissolution temperatures using equations by sterner et al. (1988), salinities of low-salinity inclusions were calculated by ice melting temperatures using equations by bodnar (1993), while the salinities of inclusions that homogenize by salt dissolution were determined by equations provided by lecumberrisanchez et al. (2012). data for the pressure calculation of boiling fluids were calculated in aqso_nacl software (bakker, 2018), based on equations by haar (1984) and driesner & heinrich (2007). the information from the analyzed samples is summarized in table 2, including not only the number of analyzed inclusions table 1. paragenetic sequence of veins in the porphyry zone of čukaru peki. quartz veins magnetite veins purple anhydrite veins sulphide veins pyrite chalcopyrite bornite magnetite hematite pyrrhotite rutile covellite enargite gold figure 4. types of veins in the porphyry zone of čukaru peki: a) quartz b vein crosscutting smaller quartz a veins in diorite fmtc1328 930.7m; b) sample with pyrite d vein and thin orange anhydrite vein fmtc1328 1581,5m c) thin sulphide vein crosscutting magnetite vein fmtc1327 1350m d) thin sulphide vein crosscutting a purple anhydrite vein fmtc1328 1589m 1139.7m; e) orange anhydrite vein crosscutting an earlier quartz b vein fmtc1327 1474m. g eologia c roatica velojić et al.: fluid evolution of the čukaru peki cu-au porphyry system (east serbia) inferred from a fluid inclusion study 201 in the different types of veins, but also the depth of samples, modes of homogenization and the obtained average homogenization temperatures and salinities. a raw data table with all the measurements is provided in the appendix. 4. results 4.1. types of fluid inclusions several types of fluid inclusion assemblages (fias) were distinguished in veins in the porphyry zone of čukaru peki. according to goldstein & samson (2003), a fluid inclusion assemblage comprises a discriminated group of petrographically associated fluid inclusions, which are assumed to be trapped coevally. criteria for the determination of primary fluid inclusions includes inclusions which are trapped along the growth zones of minerals or inclusions which are randomly scattered throughout a quartz crystal (roedder, 1984; goldstein & samson, 2003, mao et al., 2017). if such a group of fluid inclusions with similar phase proportions at room temperature yields similar melting and homogenization temperatures, it is inferred that they belong to a primary assemblage. on the other hand, secondary fluid inclusion assemblages are aligned in planar arrays or along curved surfaces that crosscut crystal growth zones. (goldstein & samson, 2003) it should be noted that precise genetic determination of fluid inclusion assemblages in minerals in porphyry systems, by specific orientation in a mineral growth zone, or by alignment in planar arrays in crystals, is rarely straightforward because of the presence of numerous healed fractures and growth zones. (john et al., 2010) photomicrographs of different fluid inclusion assemblages are shown in figure 5 and zoomed photomicrographs of individual inclusions are shown in figure 6. three different associations of fluid inclusions are distinguished in the studied quartz veins from čukaru peki: 1) primary association 1: (type 1) primary three-phase inclusions (gas + liquid ± halite) (fig. 6a). the criterion for the identification of these fluid inclusions as petrologically primary is the fact that they were trapped in crystal growth zones in quartz veins (as seen on fig. 5a and fig. 5d). these inclusions often have a negative-crystal shape and they contain a relatively large bubble; phase composition at room temperature is: >30 %v ±10-20%s+ 50-60% % l. most of these inclusions contain a small halite crystal, which implies they are probably high-temperature brines. 2) brine association 1: (type 2a) polyphase brine inclusions with two salt phases (gas + liquid + 2 solid phases± hematite± opaque mineral) (fig.6b). these inclusions are distinguished by the presence of 2 or more salt crystals. considering the crystal habitus (cubic and anhedral), transparency and refractivity of the two salt crystals, they are assumed to be nacl and kcl crystals. these salts are also the most common solid phases in brine inclusions in porphyry deposits (roedder, 1984; wilkinson, 2001; lecumberri-sanchez et al., 2012). these inclusions are commonly found in same quartz crystals as type 2b and type 3 inclusions, but in most cases, they are scattered in quartz crystals (fig. 5b and fig. fig.5d).phase composition at room temperature is: 20 %v + 30-40%s+40-50% l. 3) brine association 2: this association contains three different types of inclusions: type 2b: polyphase brine inclusions with two salt phases (gas + liquid + 2 solid phases± opaque mineral± hematite). these inclusions are quite similar to type 2a, but they are larger and they appear in the same quartz growth zones as type 3 inclusions. type 3: polyphase brine inclusions with only one salt crystal (gas + liquid + halite ± opaque mineral) (fig. 6c). the opaque mineral in these inclusions was not identified by other methods, but according to its habitus and the mineral composition of veins, it is likely that it is chalcopyrite. as for the previous type, these inclusions occur either in quartz growth zones or in clusters in quartz veins (fig. 5b and fig. 5c). they commonly occur in the same assemblages as type 2b and type 4 inclusions. phase composition at room temperature is: 20 %v + 20-30%s+50-60 % l. type 4 (fig. 6d): apparently single-phase dark vapour-rich inclusions are usually small and they are common in most of the analyzed quartz samples. the apparent single phase appearance does not exclude the presence of a thin liquid film along the walls of the inclusions. these commonly occur in similar assemblages to the type 2b and type 3 inclusions (fig. 5c), but they are also sometimes randomly distributed throughout quartz crystals. table 2. summary data for fluid inclusion analysis. for many inclusions, salinities were not measured due to their small size. vein type samples fluid inclusion type mode of homogenization number of analyzed inclusions sample depth th (mean±std) th(min) th(max) tm (phase) tm (mean) salinity (mean±std) quartz a cp105, cp106, cp123, cp141, cp143 1 lsv→lv→l 7 930-1693m 580±20.35 (for inclusions with th<600) 545.8 >600 halite 268.8 35.6±5.2 4 lv→v 3 1622m 396±20 389 428 quartz b cp089, cp096, cp105, cp106, cp116 2 lsv→ls→l 5 930-1796m 350±12.8 326 356 halite 350 43±1.2 2 lsv→lv→l 2 930m 442±40 414 470 halite 359 43±0.6 3 lsv→lv→l 11 930-1796m 385±50.3 342 495 halite 278.7 36.5±3.1 4 lv→l 7 1447-1796m 387±26.7 331 413 7 lv→l 8 930-1447m 117.5±26.4 69.2 161 purple anhydrite cp069,cp108, cp110, cp123 5 lv→l 37 1080-1610m 298±37.2 225 396 ice -2.3 3.87±2.1 6 lv→l 16 1080-1610m 200±41.8 131 291.7 ice -2.3 3.87±1.5 orange anhydrite cp108, cp141 7 lv→l 8 1116-1622m 89.6±27.3 73 138.5 ice -2.65 4.4±0.3 g eo lo gi a c ro at ic a geologia croatica 73/3202 in purple anhydrite veins, two types of assemblages can be distinguished: 1) type 5: gaseous fluid inclusions in purple anhydrite (vapour + liquid ± opaque mineral) (fig. 6e). these inclusions are probably primary inclusions in anhydrite because they have negative square crystal shapes and follow the growth zones of the anhydrite crystals (fig. 5e and fig. 5f). phase composition at room temperature is: 20 %v + 80 % l. 2) type 6: aqueous inclusions in anhydrite (vapour + liquid) (fig. 6e) are probably secondary inclusions because they are scattered in anhydrite or they follow the directions of later cracks (fig. 5f). their bubble is significantly smaller than type 5 inclusionsphase composition at room temperature is: 5-10 %v + 9095 % l. beside these types, there are also assemblages of secondary inclusions, which are present both in quartz veins and in orange anhydrite veins: type 7: late aqueous inclusions (vapour + liquid ± opaque mineral) are secondary inclusions. (fig. 6f). it is assumed that these are low temperature inclusions, since the bubble is very small, phase composition at room temperature is: 5-10 %v + 9095 % l. these inclusions are common in most of the analyzed samples, especially in quartz veins and orange anhydrite veins. these inclusions are often in linear assemblages which follow the directions of late cracks. (fig.5a) present opaque minerals were not identified, but their elongated habitus is quite different from the opaque minerals in type 2a, 2b and type 3 inclusions. 4.2. microthermometric results some of the recognized fluid inclusion assemblages were not adequate for microthermometric measurements, due to the small size of the present inclusions (<5μm), which hinders the visual recognition of phase transitions. this problem was especially present while measuring type 4 inclusions. also, fluid inclusions that appear to be leaked and the inclusions that display “necking down” features were not measured by microthermometry in order to avoid the impact of reequilibration processes. (roedder, 1984; bodnar & samson, 2003) generally speaking, there are four different modes of homoge nization of analyzed fluid inclusions from čukaru peki: figure 5. types of fluid inclusion assemblages in veins in čukaru peki. legend: a) primary type 1 assemblage in growth zone in quartz, crosscut by secondary assemblage of type 7 inclusions fmtc1327 1315,5m; b) brine association 2 with type 2b and type 3 inclusions in growth zone in quartz b vein fmtc1328 953,7m; c) brine association 2: type 3 inclusions with opaque mineral with type 4 vapour inclusions in quartz growth zone fmtc1327 1796,3m; d) type 1 inclusions in growth zones in quartz vein and scattered type 2a inclusions fmtc1327 1315,5m; e) primary assemblage of type 5 inclusions in square crystal of anhydrite fmtc1328 1139,7m; f) primary type 5 inclusions, crosscut by secondary aqueous type 6 inclusions in anhydrite fmtc1328 1610,5m. orientations of primary assemblages are marked with blue lines, while the orientations of secondary inclusions are marked with a green line. g eologia c roatica velojić et al.: fluid evolution of the čukaru peki cu-au porphyry system (east serbia) inferred from a fluid inclusion study 203 lsv→lv→l, lsv→ls→l, lv→v and lv→l. total homogenization occurs over a very wide range of temperatures, from less than 100°c to more than 600°c, and the salinity of the inclusions is quite variable (0-44 wt.% nacl eq.), which is also reported in many other porphyry deposits worldwide (e.g. bodnar et al., 2014). frequency distribution diagrams of the measured homogenization temperatures and salinities of different types of inclusions are presented in fig. 7. primary association (type 1) inclusions are probably formed at very high temperatures because most of them did not homogenize at 600°c, which is the limit of the heating stage employed. only three of the measured fluid inclusions reached total homogenization at 546, 580 and 582°c. the mode of homogenization for all of these inclusions was: lsv→lv→l. salinities of these inclusions were determined by halite dissolution temperatures and they vary from 30 to 44 wt.% nacl eq. homogenization temperatures of type 2a inclusions are between 320 and 470°c, with mean values around 350°c. the interesting feature of these brines is that they homogenize by halite dissolution, after the homogenization of the bubble (lsv→ls→l). the common homogenization sequence of these inclusions starts with the first salt crystal dissolving between 150 and 200°c, it is followed by homogenization of the bubble and ends by the second salt crystal dissolving, around 350-400°c. the low melting temperature of the first salt crystal suggests these salt crystals are sylvite. this mode of homogenization excludes the trapping of these inclusions from boiling fluids. (lecumberri-sanchez et al., 2012). however, two of the measured type 2b inclusions homogenized by bubble homogenization, after the dissolution of salt crystals (lsv→lv→l). their homogenization temperatures were 414 and 470°c. the inclusions which contain two salt crystals are modeled by nacl-kcl-h2o system (roedder, 1984), where the total salinity in fluid inclusions containing both nacl and kcl crystals is calculated from the dissolution temperature of the first salt crystal that occurs at the cotectic line and the dissolution temperature of the second salt crystal, which is reflected by the isotherms in a specific field (bakker, 2012). salinities for these inclusions are calculated by equations and cotectic lines given by sterner et al. (1988). homogenization temperatures of type 3 inclusions are between 340 and 490°c, with mean values around 380°c, whereas their salinity ranges between 28 and 38 wt.% nacl eq. the mode of homogenization for all of these inclusions was: lsv→lv→l. homogenization of the opaque phase was not observed, which could be explained by hydrogen diffusion, which reduces the figure 6. zoomed photomicrographs of fluid inclusions in assemblages (at room temperature). legend: a) zoomed primary type 1 inclusions in growth zone in quartz, zoomed from fig.5a; b) polyphase type 2a inclusions with 2 salt crystals and opaque mineral in quartz fmtc1327 1315,5m; c) type 3 inclusion with opaque mineral in quartz fmtc1327, zoomed from fig.5c; d) type 4 inclusion fmtc1328 1527m; e) gaseous type 5 inclusions and aqueous type 6 inclusions in anhydrite, zoomed from fig.5f; f) secondary aqueous type 7 inclusions with small opaque phases, zoomed from fig.5a g eo lo gi a c ro at ic a geologia croatica 73/3204 solubility of the sulfide minerals in inclusions (mavrogenes & bodnar, 1994). some of the measured type 4 inclusions homogenized to vapour (lv→v at 389, 428 and 485°c), while the rest of them homogenized to liquid (lv→v). the mean temperature of homogenization is around 390°c. due to their small size and dark appearance, suitable ice melting experiments were not possible, so their exact salinity is unknown. given that there are no visible salt crystals, their salinity is most likely lower than 20 wt.% nacl eq. homogenization temperatures of type 5 inclusions vary between 245 and 396°c, with a mean homogenization temperature of around 297°c. the mode of homogenization for all of these inclusions was: lv→l. ice melting temperatures in these inclusions are between -0.5 and -4.4°c, which corresponds to salinities between 0.87 and 7 wt.% nacl eq. (bakker, 2018; according to equations by potter et al., 1978). it should be noted that most of the measurements on anhydrite crystals were only performed once, due to the phenomenon of thermal expansion of anhydrite during heating which may affect homogenization temperatures. another problematic phenomenon which sometimes occurs is the stretching or decrepitation of the inclusions if they are heated above their homogenization temperature (vanko & bach, 2005). homogenization of the opaque phase was not observed. the mode of homogenization for all of these inclusions was: lv→l. their salinities vary between 3 and 7.2 wt.% nacl eq. as for the previous type of inclusions, measurements were only performed once, to prevent the effects of the thermal expansion of anhydrite and the stretching of fluid inclusions . measured homogenization temperatures of the type 7 inclusions are between 73 and 161°c, with mean values around 117°c. the mode of homogenization for all of these inclusions was: lv→l. the salinities of measured inclusions are between 4 and 5 wt.% nacl eq. homogenization of the opaque phase was not observed. discussion considering the occurrence of primary fluid inclusions in inner quartz growth zones (fig. 5a and 5d), their high homogenization temperatures (usually above 600°c) and high salinity (30–44 wt. % nacl eq.), it can be concluded that these fluid inclusion assemblages (classified as type 1) trapped the earliest fluids in this porphyry system. similar inclusions have been recognized in other porphyry deposits worldwide and they are usually considered relicts of magmatic–hydrothermal fluids that are exsolved from the cooling magmatic body. these inclusions are usually found in the deeper parts of porphyry systems, where the pressure is sufficiently high to prevent boiling (redmond et al., 2004, rusk et al., 2008). the following stage in the fluid evolution of čukaru peki was marked by the trapping of brine inclusion assemblages with 2 or more solid phases (type 2a inclusions). the presence of polyphase inclusions with 2 salt crystals is not uncommon for porphyry systems (eg. wilkinson, 2001), and the observed homogenization features imply that these fluids had a complex composition and high salinity (> 40 wt.% nacl eq.) (lecumberri-sanchez et al., 2012). considering the habitus, isotropic optical properties, low refractivity index of the second solid phase and its low dissolution temperature, it can be concluded that it is kcl (sylvite). the scattered distribution of these inclusions as well as their homogenization mode implies that these inclusions are not trapped by boiling fluids. this further implies that these inclusions trapped a k-rich fluid, which caused potassic alteration in the early porphyry stage. occasionally, the presence of hematite in these inclusions implies that these fluids were also fe-rich. the coexistence of numerous vapour-rich inclusions (type 4) in the same quartz crystals as high-salinity brine assemblages (type 2b and type 3) as an association is considered to be evidence of boiling in the system. (heinrich, 2005). according to lecumberri-sanchez et al. (2015), halite saturation in porphyry systems has important implications for the reduction of permeability in the system and promotes the precipitation of ore minerals. according to sillitoe (2010), porphyry mineralization in shallow porphyry systems (<4 km deep) is the product of a two-phase fluid, commonly consisting of a small amount of highly saline liquid (brines) and a larger amount of low-salinity vapour. in these systems, the liquid phase is enriched in na, k and fe chlorides, which results in high salinity (35 to 70 wt. % nacl eq.), while the vapour phase contains acidic volatiles, such as so2, co2, h2s, hcl etc. in čukaru peki, this highly saline liquid phase was trapped in brine inclusion assemblages (type 2b and type 3), whereas the vapour phase was trapped in small type 4 inclusions throughout the same crystals. considering the measured homogenization temperatures and halite melting temperatures of these three types of inclusions, it can be concluded that the process of boiling and separation of phases occurred at temperatures between 350 and 450 °c, with fluid salinities of the brines between 30 and 40 wt.% nacl eq, which led to ore deposition. the detection of the boiling of fluids enables the calculation of pressure in the system and the palaeodepth of ore-forming processes (fournier, 1999; redmond et al., 2004; rusk et al., 2008; mao et al., 2017; li et al., 2019). pressure estimates for boiling fluids were calculated for halite-bearing inclusion assemblages (type 2b and type 3). brine inclusions which homogenized by halite dissolution were not included in the calculation, since they were not trapped from boiling fluids (lecumberrisanchez et al., 2015). calculated pressure estimates yielded values between 100 and 500 bar. according to the pressure/depths diagrams presented by fournier (1999) and redmond et al. (2004) this pressure corresponds to fluctuations between lithostatic and hydrostatic pressure at palaeodepths between 1 and 2 kilometres . these pressure estimates are shown on the pressuretemperature diagram for nacl-h2o system in figure 8. the conclusion that ore deposition in the porphyry zone of čukaru peki occurred at these temperatures is in accordance with fluid evolution studies in the nearby majdanpek porphyry system (strashimirov (1997), but similar processes were also identified in other porphyry deposits. for example, heinrich et al. (2005) argue that ore deposition in porphyry copper deposits ideally happens around 400°c at low pressures, caused by the drop in solubility of cu-fe sulphides. also, orlandea & vlad (2020) state that cu-au porphyry systems are characterized by boiling of fluids between 500 and 400°c and pressures of 0.4 to 0.5 kbars. it is generally assumed that the separation of the initial fluid to high-salinity brines and low-salinity vapour (at depths between 2-4 km) is followed by the rise of these fluids through the magma to the cupola zone (redmond et al., 2004; richards, 2005), which explains why these two types of fluids can be found at different levels vertically within the porphyry zone of čukaru peki. as indicated in figure 9, inclusion types 5, 6 and 7 have significantly lower salinities than early brines, so this implies that the transition to the epithermal stage happened by cooling and diluting of the fluids. according to sillitoe (2010), in the later g eologia c roatica velojić et al.: fluid evolution of the čukaru peki cu-au porphyry system (east serbia) inferred from a fluid inclusion study 205 figure 7. frequency distribution diagrams of measured homogenization temperatures and salinities of different types of fluid inclusions from čukaru peki. type 2a refers to brine inclusions which homogenize by halite dissolution, while 4a refers to inclusions type 4 which homogenize to vapour. figure 8. pressure-temperature diagram for nacl-h2o system (modified from fournier, 1999 and redmond et al., 2004) showing pressure estimates for brine fluid inclusions (type 2b and type 3) from čukaru peki. g eo lo gi a c ro at ic a geologia croatica 73/3206 stages of the evolution of porphyry systems, low-salinity fluids (5–20% nacl eq.) with temperatures between 250 and 350°c are introduced in the system from the parental magma chamber. the most representative sample for fluids in the transition zone is sample cp069 because it was sampled in the lower andesites high above the porphyry zone. considering the facts that anhydrite veins commonly contain covellite and enargite and that gypsum is a common mineral in the high-sulphidation zone, it is possible that anhydrite inclusions in the transitional zone (types 5 and 6) trapped part of the fluids which deposited massive sulfides with covellite and enargite. however, previous fluid inclusion research on high-sulphidation mineralization in the bor metallogenic zone (koželj, 2002; bailly et al., 2002) yielded somewhat lower temperatures (around 150-250°c) than those inferred by our study of type 5 inclusions from čukaru peki. another problem is that type 6 inclusions are usually related to later cracks in the analyzed veins, so their genetic link with any of the analysed veins or stages of mineralization is uncertain. sulphide veins in the transition zone are probably the remains of epithermal fluid flow paths to the high sulphidation zone since they contain larger amounts of pyrite, covellite and enargite. however, they do not contain transparent minerals, which makes them incompatible for standard fluid inclusion analysis using transmitted light microscopy.. thus, further analyses of highsulphidation minerals (including infrared microthermometry) are needed for better constraining of fluid characteristics that led to deposition of massive sulfides. fluids trapped in inclusions type 6 and 7 are likely post-ore fluids, since their homogenization temperature is low and they are trapped in secondary inclusions in later cracks. conclusions according to the presented petrographic observations of fluid inclusion assemblages from čukaru peki, together with the performed microthermotetrical measurements, it can be concluded that this hydrothermal system was formed in several different stages: analyzed quartz veins contain three types of primary inclusion assemblages: 1) primary high-temperature assemblages (type 1) with homogenization temperatures above 550°c and high salinities. 2) brine inclusion assemblages (type 2a) with two or more solid phases (2 salt crystals± opaque crystal±hematite), scattered in quartz crystals. 3) the brine inclusion association containing 1) brine assemblages with salt crystals and opaque minerals (with occasional hematite) (type 2b and type 3) and 2) apparently single-phase lowsalinity vapour-rich inclusions (type 4). most of the inclusions in this association homogenize at around 400°c. the coexistence and similar temperatures of homogenization of these three types of inclusions imply that these assemblages were trapped during the boiling of high-temperature fluids. considering the measured homogenization temperatures and estimated entrapment pressures of these coexisting inclusion assemblages, it is estimated that the boiling of fluids in this system occurred at temperatures between 350 and 450°c and pressures between 100 and 500 bars. the boiling of fluids was probably a very important factor in deposition of porphyry style mineralization in this system. analysed anhydrite veins contain two types of inclusion assemblages: figure 9. plot of microthermometric measurements (salinity vs. homogenization temperature (th) diagram) for different inclusions from čukaru peki. data for the h20 critical curve and the nacl saturation curve are given by haas (1976) and data for the kcl saturation curve is given by potter et al. (1978). type 4 inclusions are not plotted on this diagram because there were no salinity (ice melting) measurements for these inclusions. several type 1 inclusions didn’t homogenize until 600°c (the limit of the used heating stage), so they are plotted around 650°c. g eologia c roatica velojić et al.: fluid evolution of the čukaru peki cu-au porphyry system (east serbia) inferred from a fluid inclusion study 207 1) primary fluid inclusion assemblages (type 5) that sometimes contain opaque minerals and homogenize around 300°c. since these inclusions are primary in origin, it can be concluded that purple anhydrite and related ore minerals (which in some veins include covellite and enargite) were formed around 300°c, with salinity of fluids between 0.87 and 7 wt.% nacl eq. 2) secondary low-temperature fluid inclusion assemblages (inclusions type 6). most of these inclusions were formed at temperatures lower than 200° and they are probably not important for the mineralization. the last generation of fluids that affected this system was trapped in secondary low-temperature inclusion assemblages (type 7). these fluids are trapped in secondary inclusion assemblages in quartz and anhydrite and their homogenization temperatures do not exceed 150°c. this research has provided data about the conditions of formation of veins from the porphyry and transitional zone of čukaru peki, however additional research is required to assess the physico-chemical conditions of fluids that led to the deposition of massive sulphides. acknowledgment the authors would like to thank prof. ronald bakker for his practical advice and help with determining different types of fluid inclusions from čukaru peki. the authors are also grateful to the sample preparation lab at the department of geology and ore deposits at montanuniversitat leoben in austria for help with making double-polished sections for fluid inclusion analysis. this study is partly supported by the ceepus network and by the scientific project funded by the serbian ministry of education, science and technological development no 176016. v. cvetković is supported by the projects f17 and f9 of the serbian academy of sciences and arts. references bailly, l., stein, g. & genna, a. (2002): preliminary microthermometric measurements in quartz, sphalerite and enargite from the bor and majdanpek deposits, serbia.– in: proceedings geology and metallogeny of copper and gold deposits in the bor metallogenic zone. bor 100 years international symposium, bor lake, yugoslavia, 2002, 71–75. bakker, r j. (2012): package fluids. part 4: thermodynamic modelling and purely empirical equations for h2o-nacl-kcl solutions. mineralogy and petrology, 105/ (1–2), 1–29. doi: 10.1007/s00710-012-0192-z bakker r.j. (2018): aqso_nacl: computer program to calculate p-t-x-v properties in the h2o-nacl fluid system applied to fluid inclusion research and pore fluid circulation.– comput. geosci., 115, 122–133. doi: 10.1016/j.cageo.2018.03.003 banješević, m. & large, d. (2014): geology and mineralization of the new copper and gold discovery south of bor timok magmatic complex.– proceedings of the xvi serbian geological congress, serbian geological society, donji milanovac, 2014, 739–741. banješević, m., cvetković, v., von quadt, a., ljubović obradović, d., vasić, n., pačevski, a. & peytcheva, i. (2019). new constraints on the main mineralization event inferred from the latest discoveries in the bor metallogenetic zone (bmz, east serbia).– minerals, 9/(11), 672. doi: 10.3390/min9110672 bodnar, r.j. (1993): revised equation and table for determining the freezing point depression of h2o-nacl solutions.– geochimica et cosmochimica acta, 57, 683–684. doi: 10.1016/0016-7037(93)90378-a bodnar, r.j. & samson, i. (2003): reequilibration of fluid inclusions.– fluid inclusions: analysis and interpretation, 32, 213–230. bodnar, r.j., lecumberri-sanchez, p., moncada, d. & steele-macinnis, m. (2014): 13.5 fluid inclusions in hydrothermal ore deposits. treatise on geochemistry.– second editionth edn. elsevier, oxford, 119–142. doi: 10.1016/ b978-0-08-095975-7.01105-0 driesner, t. & heinrich, c.a. (2007): the system h2o–nacl. part i: correlation formulae for phase relations in temperature–pressure–composition space from 0 to 1000 c, 0 to 5000 bar, and 0 to 1 xnacl.– geochimica et cosmochimica acta, 71/ (20), 4880–4901. doi: 10.1016/j.gca.2006.01.033 fournier, r.o. (1999). hydrothermal processes related to movement of fluid from plastic into brittle rock in the magmatic-epithermal environment.– economic geology, 94/(8), 1193–1211. doi: 10.2113/gsecongeo.94.8.1193 gallhofer, d., von quadt, a., peytcheva, i., schmid, s.m. & heinrich, c.a. (2015): tectonic, magmatic, and metallogenic evolution of the late cretaceous arc in the carpathian-balkan orogeny.– tectonics, 34, 1813–1836. doi: 10.1002/2015tc003834 goldstein, r.h. & samson, i. (2003) petrographic analysis of fluid inclusions.– fluid inclusions: analysis and interpretation, 32, 9–53. haar, l. (1984): nbs/nrc steam tables.– crc press. haas, j.l. (1976): physical properties of the coexisting phases and thermochemical properties of the h2o component in boiling nacl solutions.– us geological survey bulletin, 1421-a, 1–71 heinrich, c.a. (2005): the physical and chemical evolution of low-salinity magmatic fluids at the porphyry to epithermal transition: a thermodynamic study.– mineralium deposita, 39/(8), 864–889. doi: 10.1007/s00126-004-0461-9 heinrich, c.a., halter, w., landtwing, m.r. & pettke, t. (2005): the formation of economic porphyry copper (-gold) deposits: constraints from microanalysis of fluid and melt inclusions.– geological society, london, special publications, 248/(1), 247–263. doi: 10.1144/gsl.sp.2005.248.01.13 janković, s. (1990): the ore deposits of serbia: regional metallogenic settings, environments of deposition, and types.– faculty of mining and geology, belgrade (in serbian with english summary). jelenković, r. (2014): a brief overview of the metallic mineral resources of serbia.– european geologist, 37, 34–38. jelenković, r., milovanović, d., koželj, d. & banješević, m. (2016): the mineral resources of the bor metallogenic zone: a review.– geologia croatica, 69/ (1), 143–155. doi: 10.4154/gc.2016.11 john, d.a., ayuso, r.a., barton, m.d., blakely, r.j., bodnar, r.j., dilles, j.h. & taylor, r.d. (2010): porphyry copper deposit model.– scientific investigations report. kolb, m., von quadt, a., peytcheva, i., heinrich, c.a., fowler, s.j. & cvetković, v. (2013): adakite-like and normal arc magmas: distinct fractionation paths in the east serbian segment of the balkan-carpathian arc.– journal of petrology, 54/(3), 421–451. doi: 10.1093/petrology/egs072 koželj, d.i. (2002): epitermalna mineralizacija zlata borske metalogenetske zone: morfogenetski tipovi, strukturno-teksturni varijeteti i potencijalnost [epithermal gold mineralization in the bor metallogenic zone: morphogenetic types, structural-texture varieties and potentiality – in serbian, with english summary].– rtb bor, institut za bakar, indok centar. lecumberri-sanchez, p., steele-macinnis, m., & bodnar, r.j. (2012): a numerical model to estimate trapping conditions of fluid inclusions that homogenize by halite disappearance.– geochimica et cosmochimica acta, 92, 14–22. doi: 10.1016/j.gca.2012.05.044 lecumberri-sanchez, p., steele-macinnis, m., weis, p., driesner, t. & bodnar, r.j. (2015): salt precipitation in magmatic-hydrothermal systems associated with upper crustal plutons.– geology, 43/(12), 1063–1066. doi: 10.1130/ g37163.1 li, s., zhang, x. & gao, l. (2019): ore genesis at the jinchang gold–copper deposit in heilongjiang province, northeastern china: evidence from geology, fluid inclusions and h–o–s isotopes.– minerals, 9/(2), 99. doi: 10.3390/min9020099 mao, w., rusk, b., yang, f. & zhang, m. (2017): physical and chemical evolution of the dabaoshan porphyry mo deposit, south china: insights from fluid inclusions, cathodoluminescence, and trace elements in quartz.– economic geology, 112/(4), 889–918. doi: 10.2113/econgeo.112.4.889 mavrogenes, j.a. & bodnar, r.j. (1994): hydrogen movement into and out of fluid inclusions in quartz: experimental evidence and geologic implications.– geochimica et cosmochimica acta, 58/(1), 141–148. doi: 10.1016/0016-7037(94)904529 neubauer, f. (2002): contrasting late cretaceous with neogene ore provinces in the alpine-balkan-carpathian-dinaride collision belt.– geological society london special publication, 204, 90–100. doi: 10.1144/gsl.sp.2002.204.01.06 ni 43-101 (2016): preliminary economic assessment of the cukaru peki upper zone deposit, serbia, march 2016. orlandea, e. & vlad, ş.-n. (2020): a novel conceptual model of intrusion related gold bearing systems and exploration tools.– studia ubb geologia 63/(1), 1–12. doi: 10.5038/1937-8602.63.1.1304 potter, r.w., clynne, m.a. & brown, d.l. (1978): freezing point depression of aqueous sodium chloride solutions.– economic geology, 73/(2), 284–285. doi: 10.2113/gsecongeo.73.2.284 redmond, p.b., einaudi, m.t., inan, e.e., landtwing, m.r. & heinrich, c.a. (2004): copper deposition by fluid cooling in intrusion-centered systems: new insights from the bingham porphyry ore deposit, utah.– geology, 32/(3), 217–220. doi: 10.1130/g19986.1 g eo lo gi a c ro at ic a geologia croatica 73/3208 richards, j.p. (2005): cumulative factors in the generation of giant calc-alkaline porphyry cu deposits.– super porphyry copper and gold deposits: a global perspective, 1, 7–25. roedder, e. (1984): fluid inclusions.– de gruyter, broj stranica. rusk, b.g., reed, m.h. & dilles, j.h. (2008): fluid inclusion evidence for magmatic-hydrothermal fluid evolution in the porphyry copper-molybdenum deposit at butte, montana.–economic geology, 103/(2), 307–334. doi: 10.2113/gsecongeo.103.2.307 sillitoe, r.h. (2010): porphyry copper systems.– economic geology, 105/(1), 3–41. doi: 10.2113/gsecongeo.105.1.3 steele-macinnis, m., lecumberri-sanchez, p. & bodnar, r.j. (2012): hokieflincs-h2o-nacl: a microsoft excel spreadsheet for interpreting microthermometric data from fluid inclusions based on the pvtx properties of h2o–nacl.– computers geosciences, 49, 334–337. doi: 10.1016/j.cageo.2012.01.022 sterner, s.m., hall, d.l. & bodnar, r.j. (1988): synthetic fluid inclusions. v. solubility relations in the system nacl-kcl-h20 under vapor-saturated conditions.– geochimica et cosmochimica acta, 52, 989–1005. strashimirov, s. (1997): new data about the development of hydrothermal system in the majdanpek porphyry copper deposit.– in proceedings of symposium “ore deposit exploration“, belgrade 2-4.april 1997, 409–418. vanko, d.a. & bach, w. (2005): heating and freezing experiments on aqueous fluid inclusions in anhydrite: recognition and effects of stretching and the low-temperature formation of gypsum.– chemical geology, 223/(1–3), 35–45. doi: 10.1016/j.chemgeo.2004.11.021 velojić m. & erlandsson, b.v.(2019): trace elements in different veins by laicp-ms in chukaru peki high sulfidation deposit, serbia.– in: 1st international student conference on geochemistry and mineral deposits, prague. wilkinson, j.j. (2001): fluid inclusions in hydrothermal ore deposits.– lithos, 55/ (1–4), 229–272. doi: 10.1016/s0024-4937(00)00047-5 g eologia c roatica velojić et al.: fluid evolution of the čukaru peki cu-au porphyry system (east serbia) inferred from a fluid inclusion study 209 spot number type of inclusions tm(°c) phase th (°c) 143-3 1 580 143-3 1 >600 106-4 1 268.8 halite >600 106-4 1 160 halite 582 123-5 1 157.5 halite 545 105-3b 1 327 halite >600 105-3b 1 328.2 halite >600 105-2b 1 373 halite >600 105-2b 1 248.7 halite >600 96-2 2a 356 halite 356 106-1 2a 350 halite 350 116-6 2a 326 halite 326 106-1 2a 350 halite 350 105-3b 2a 333 halite 333 105-2a 2b 353.9 halite 414 105-2a 2b 364.1 halite 470 96-2 3 263 halite 407 96-2 3 278.7 halite 375 96-2 3 280 halite 495 116-6 3 300 halite 474 116-8 3 293 halite 434 106-4 3 290 halite 452 89-4 3 253 halite 379 89-4 3 281 halite 351 89-3 3 254.4 halite 384 123-8 3 146.8 halite 380 105-3a 3 127.4 halite 342 96-2 4 403 96-2 4 387 96-3 4 331 89-4 4 371 89-4 4 390 141-8 4a 389 141-9 4a 428 141-9 4a 396 89-3 4 414 89-3 4 377 69-1 5 -4.4 ice 279 69-2 5 297 69-3 5 298 69-4 5 249 69-5 5 283 69-6 5 299 69-7 5 316 69-8 5 299 69-9 5 248 69-10 5 301 69-11 5 298 69-12 5 255 69-13 5 345 69-14 5 321 69-15 5 225 69-16 5 258 spot number type of inclusions tm(°c) phase th (°c) 69-17 5 290 69-18 5 334 69-19 5 302 69-20 5 267 110a 5 -2.3 ice 289 110a 5 -3.5 ice 318 110a 5 -1.7 ice 245 110g-3 5 -2 ice 251 110g-3 5 -0.9 ice 300 110-6 5 -2.9 ice 290 110-7 5 -0.5 ice 329 108-3b 5 -4 ice 323 108-3b 5 330 108-3b 5 372 108-3b 5 396 108-4 5 -0.5 ice 353 108-4 5 294 110g-3 5 277 110g-3 5 286 123-1 5 -2.7 ice 310 123-1 5 356 110-7 6 -3.3 ice 211 116-8 6 237 69-1 6 220 69-2 6 204 69-3 6 179 108-3b 6 -2.4 ice 209 108-5 6 -1.8 ice 292 108-5 6 -1.9 ice 217 110g-1 6 143 110g-4 6 176 110g-4 6 155 110g-4 6 146 123-1 6 -2 ice 197 123-1 6 -2.3 ice 154 123-1 6 -4.5 ice 215 110a 6 -2.3 ice 131 89-3 7 111 89-3 7 115 89-3 7 117 89-3 7 118 89-3 7 120 89-3 7 142 141-7 7 73 141-7 7 87 108-3a 7 91 108-3a 7 89 108-3a 7 -2.5 ice 131 108-3b 7 76 108-5 7 -2.8 ice 134 108-5 7 139 105-3b 7 69 105-3b 7 161 appendix table with all microthermometry measurements conducted on analyzed sam-ples from čukaru peki. 2018 | 71/2 | 45 | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society dear colleagues, the croatian national chapter of the international association of hydrogeologists hosted the 44th annual congress “groundwater heritage and sustainability” in the dubrovnik palace hotel, dubrovnik, croatia, from 25th to 29th september 2017. scientific part of the congress was held in 8 topics and 36 sessions. main topics covered: (1) groundwater heritage with the focus on groundwater reserves as well as groundwater quality by passing benefits from past to current, and from current to future generations; (2) sustainable management of groundwater resources necessary to control the risks and pressures on groundwater caused by existing and increasing anthropogenic pressures, as well as present climate change and variations; (3) groundwater modelling highlighting the research of intergranular, karst and hard rock systems and presenting various modelling approaches, both analytical and numerical, for solving groundwater flow and contaminant transport problems in groundwater resources management and protection; (4) new approaches and technologies in groundwater monitoring used in monitoring and characterization of quality and quantity status of groundwater, as well as in biological monitoring of underground aquatic ecosystems; (5) groundwater in karst systems focusing on specifics of groundwater flow in karst environment, bifurcations, trifurcations, accumulating groundwater in karst environments, impact of karst groundwater on rock characteristics, speleogenesis in karst hydrogeology, significant hydrogeological phenomena in dinaric karst and significant hydrogeological phenomena worldwide; (6) coastal and island hydrogeology comprising specific problems of groundwater in coastal and island areas under influence of seawater penetration, as well as future climate and sea level changes; (7) groundwater and dependent ecosystems considering underground ecosystems and terrestrial groundwater dependent ecosystems; and (8) mineral and geothermal waters presenting the practice of using mineral and geothermal waters for treatment and curing of diseases as well as heating. this issue of geologia croatica journal dedicated to the 44th annual congress of the iah presents 7 papers which elaborate on 4 of the topics covered at the congress. papers present achievements in sustainable management of groundwater resources focusing on transdisciplinary and participatory approaches in groundwater research and management, regulatory framework of groundwater management and groundwater quality and natural environmental tracers. further, papers present achievements in groundwater flow and transport modelling as well as monito­ ring of groundwater quality and contamination. we wish to express our gratitude to authors and reviewers and we hope that presented papers will be useful not only to hydrogeologist but also to other professionals as well. kristijan posavec, issue editor tamara marković, issue editor lidija galović, editor-in-chief 44th annual congress “groundwater heritage and sustainability” doi: 10.4154/gc.2018.13 2023 | 76/3 | 131–146 | 8 figs. | 2 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction time series analysis is the application of mathematical and statistical tests to time-varying data to quantify the variation and gain some physical understanding of the system behaviour (templeton, 2004). many systems are monitored and evaluated for their behaviour using time signals; additional information about the properties of a time signal can be obtained by representing the time signal by a series of coefficients based on an analysis function. one example of a signal transformation is the transformation from the time domain to the frequency domain. the oldest and probably best-known method for this is the fourier transform (merry, 2005). in the frequency domain, fourier transform (ft) deals with infinite sines and cosines as base functions to decompose stationary time series (potočki et al., 2017). this transform calculates the relative intensity of each frequency component of the whole signal (the global frequency content of signals), but the time information is lost (gurley & kareem, 1999a; shok­ rollahi et al., 2013). that is to say, a short­duration, high­ frequency phenomenon is buried in a fourier representation with the average background spectral content (gurley & kareem, 1999a). this is overcome by the short­time fourier transform (stft), which divides a non­stationary signal into continuous wavelet transformation to quantify small-scale cycles of petrophysical properties; a new approach applied in a potential disposal repository of nuclear waste, sw hungary saja m. abutaha1*, jános geiger1, ferenc fedor2 and sándor gulyás1 1 university of szeged, department of geology and paleontology, egyetem utca 2-6, 6722 szeged, hungary; (*corresponding author, orcid no. 0000-0001-8439-5895, sajaabutaha@geo.u-szeged.hu) 2 geochem ltd, 55/1 viola str, 7761 kozármisleny, hungary doi: 10.4154/gc.2023.11 abstract continuous wavelet transformation (cwt) was applied to study the small-scale repetitive oscillations of porosity distribution patterns in a 5 m silty-claystone core sample of the boda claystone formation. we handled the fluctuations in voxel porosity averages over unequal depth distributions as signals over uneven time intervals. the strength of wavelet analysis lies in the ability to study the fluctuation of a signal in detail, i.e., the wavelet transforms permit automatic localization of the cyclic attributes’ sequences both in time (the depth domain) and according to their frequency (the frequency domain). thereupon, three main frequency branches (cycles) were discerned: small scale (5, 6.67, and 11 cm), intermediate scale (20, 30 cm), and large scale (66.67 cm). depending on the cwt coefficients magnitude plot, we were able to detect the developments of porosity oscillation according to the depth variable. thus, small-scale cycles were seen throughout the core sample., the intermediate-scale cycles were strong in the upper parts of the core sample and dwindled toward greater depths, and the large cycle was predominant in the lower part of the core sample. the cross-correlation of the wavelet coefficients of porosity and rock-forming components allows a detailed study of the inter-dependence of such parameters as their relationship changes over time. the distinct peaks at zero lag indicates that the measured wavelet coefficient series were contemporaneously correlated; their strong positive correlations suggest that both examined series respond similarly and simultaneously to other exogenous factors. the results emphasize that cyclical porosity fluctuations at all scales would concern three main factors; sediment deposition, diagenetic processes, and structural deformation (i.e., convolute laminations). small segments (stationary parts), calculates the fourier transform of a windowed part of the signal, and shifts the window over the signal. the short-time fourier transform gives the time-frequency content of a signal with a constant frequency and time resolution due to the fixed window length. thus, a short temporal window provides suitable time resolution, but the resulting frequency resolution is low. if a larger temporal window is selected, frequency resolution will be improved, but time resolution will be reduced (templeton, 2004; merry, 2005; shokrollahi et al., 2013). the wavelet transform is a computationally efficient technique for extracting information about transient and non-sinusoidal signals. the wavelet transform (wt) and more particularly the continuous wavelet transform (cwt) is calculated analogously to the fourier transform by the convolution between the signal and analysis function. however, the trigonometric analysis functions are replaced by a wavelet function (mother wavelet). from this, the continuous wavelet transform retrieves the timefrequency content information with an improved resolution compared to the stft (merry, 2005; labat, 2010; panda et al., 2000; potočki et al., 2017). wavelet analysis is a rapidly developing area in many disciplines of science and engineering. for example, the wavelet transarticle history: manuscript received november 15, 2022 revised manuscript accepted september 22, 2023 available online october 30, 2023 keywords: x-ray computed tomography, voxel-porosity, continuous wavelet transform c/b g eo lo gi a c ro at ic a geologia croatica 76/3132 form originated in geophysics in the early 1980’s for the analysis of seismic signals and is now being exploited for the analysis of several other geophysical processes such as spatio-temporal rainfall patterns, layered structures, and climate change. moreover, the application of one-directional wavelet analysis has become wide spread in various fields of geosciences, such as gravity analysis (martelet et al., 2001, ouadfeul et al., 2010), lithofacies segmentation (ouadfeul & aliouane, 2011), geophysics (chamoli, 2009), seismic data analysis (ouadfeul, 2007), hydrology and water resources, discharge and suspended sediment, and reservoir-data analysis, i.e., permeability data (labat, 2010; gurley & kareem, 1999a; panda et al., 2000; potočki et al., 2017), and also to detect gradual and abrupt changes in the sedimentation rate, discontinuities, and superimposed periodic cycles (prokoph & barthelmes, 1996). in this study, the cwt was applied to track the small-scale repetitive oscillations of porosity distribution patterns in a 5 m silty-claystone core sample. the computed tomography scan images (ct) lay the foundation for obtaining voxel datasets on the millimetre scale. fluctuations in voxel porosity averages over unequal depth distributions were handled as signals over uneven time intervals. the cross­correlation of the wavelet coefficients of the voxels dataset allows quantification of the similarities of the wavelet coefficients of porosity and rock­forming components on large, medium, and small-scale cycles, both contemporaneously and at various lagged values. currently, there is no general framework for modeling or tracking the repetitive oscillations of porosity distribution patterns in clastic rocks. however, applying such a method grants a unique insight into the cyclical behaviour of the studied parameter (petrophysical properties, i.e., porosity) and provides a reference basis for interpreting the fluctuation patterns based on sedi­ ment depositions, structural deformation, and diagenetic processes constraints. 2. geological setting we investigated a silty claystone core sample from the boda claystone formation (bcf). it is located within the tisza mega unit, southern transdanubia, sw, hungary. during the permian, this unit was lo cated north of the equator and belonged to the southern margin of the stable european plate (csontos & vörös, 2004), where a thick conti nental clastic succession accumulated. it was detached from the southern margin of variscan europe during the jurassic (haas & péró, 2004; balla, 1987; horváth, 1993) and eventually settled in the southeastern half of the pannonian basin (fig. 1). thereby, in a figure 1. geological map of the boda claystone formation (modified after konrad et al., 2010); the star in the upper left corner shows the location of the studied core sample (ib-4). g eologia c roatica abutaha et al.: continuous wavelet transformation to quantify small-scale cycles of petrophysical properties; a new approach applied in a potential ... 133 closed, subsiding basin under arid-semiarid climate conditions (konrad et al., 2010; schneider et al., 2006), the bcf was deposited in a shallow-water lacustrine environment (playa mudflat, playa lake). the bcf occurs in two domains in the western mecsek mountains (wm mts): the boda block and the gorica block. data from boreholes and geological mappings reveal that the extension of the bcf is around 150 km2; only about 15 km2 is exposed at the boda village region in the wm mts. several deep drillings reached the bcf in the gorica block, but only borehole ib­4 recovered the bcf sequence in a significant thickness, c.a. 200 m (fig. 1). the total thickness of the bcf is estimated to be 700–900 m in the peri­anticlinal structure of the wm mts (boda block). in contrast, the overall thickness of the gorica block does not exceed 350 m (jámbor, 1964; barabás & barabás­ stuhl, 1998; máthé, 1998; árkai et al., 2000; varga et al., 2005; lázár & máthé, 2012; németh & máthé, 2016). the lithology of the bcf is characterized by small grain size (clay to silt) beds. it starts with fine­grained sandstone beds at the base overlain by albitic claystone/siltstone, with successive claystone, albitic clayey siltstone, and silty claystone, and finally dolomite at the top. the green and greenish-grey siltstones and claystones occur infrequently. desiccation cracks, dolomite concretions, convolute laminations, and crossbedding are recognized almost throughout the entire formation. (konrád et al, 2010). the stratigraphic position of the core sample studied within the core sections is shown in fig. 2. the main rock­forming minerals of the bcf are clay minerals (10–55 wt%), detrital quartz (5–30 wt%), albite (20– 60 wt%), carbonate minerals (calcite and dolomite; 10–50 wt%) and haematite (5–10 wt%) (máthé 1998, 2015; árkai et al. 2000; fedor et al., 2018). the absolutely dominant clay mineral is figure 2. general information on the studied core sample, involving stratigraphic position, geological description, textural composition, and voxel-porosity averages plot. legend abbreviations: rcf=rock-forming components, df= detrital fragments, alb=albite, car= carbonate, cl=claystone, fs= fine siltstone. g eo lo gi a c ro at ic a geologia croatica 76/3134 illite–muscovite (15–50 wt%), with chlorite (0–35 wt%) as another important clay mineral. smectite, kaolinite, vermiculite and mixed-layer clay minerals (illite/ smectite, chlorite/smectite) are identified in minor amounts (máthé 1998, 2015; árkai et al. 2000; varga et al., 2005, 2006). the illite­muscovite content decreases in the greyish-black siltstones and claystone interstratification, and chlorite becomes the dominant mineral (e.g., fedor et al., 2018). the actual investigation of the boda claystone formation as a potential host rock for high­level nuclear waste (hlw) disposal began in 1989 and has continued up to the present day. since 1998 the public limited company for radioactive waste management (puram), a hungarian government agency, has the responsibility and monetary funds for coordinating the research. in 1999, puram announced the bcf as a suitable host rock for a high­ level nuclear waste repository. this is due to a set of suitable properties of the bcf influencing radionuclide migration. for instance, it is a rather massive and homogeneous host rock, with a large extent and significant thickness (700­900 m), low bulk porosity (0.6­1.4%), appropriate hydraulic conductivity, and absence of organic residues. 3. fundamental principles of x-ray computed tomography (ct) x-ray computed tomography (ct) can provide unrivaled information about the internal structure of materials, non-destructively, from the metre down to the tens of nanometres scale (abutaha et al., 2022). it exploits the penetrating power of x­ rays to obtain a series of two­dimensional (2d) radiographs of the object viewed from many different directions. this process is called a ct scan. a computed reconstruction algorithm is then used to create a stack of cross­sectional slices from the object’s 2d projections (radiographs) (withers et al., 2021). a single ct scan image is produced using a mono­energetic x­ray. as each x­ray beam passes through the sample, it attenuates varyingly, and the transmitted x-ray is received by a detector (hounsfield, 1973). the attenuation is measured at multiple angles and reconstructed in a 3d matrix. the 3d distribution of the x­ray attenuation coefficient in reservoir or host rocks depends on mineral composition variations (atomic number and density), porosity, and saturation. x-ray attenuation is physically determined mainly by photoelectric absorption and the compton effect. photoelectric absorption is dependent on the effective atomic number and is especially important at low energies (yang et al., 2019; withers et al., 2021). the compton effect predominates at high energies, and the associated x-ray attenuation is mainly controlled by density (withers et al., 2021). just as 2d images are made up of 2d pixels, 3d images are made up of many cubic volume elements called voxels (withers et al., 2021). the x­ray attenuation can be determined using beer lambert’s law (eq. 1). each rotation of the x­ray source around the sample produces a cross-sectional image, which can then be stacked to form a 3d volume. i = i0 e–(md) (1) where i is the intensity of the transmitted x-ray, i0 is the initial x-ray intensity, m the linear x­ray attenuation coefficient, and d is the length of the x-ray path inside the object. when x-ray energy and intensity are kept constant, linear attenuation of x-ray occurs as a function of density, resulting in the sensitivity of ct images to density changes (heismann et al., 2003; duchesne et al., 2009). series of x­ray attenuation measurements are numerically processed (reconstructed) to show the spatial distribution of xray attenuation coefficients within the sample; the signals at each point in the reconstructed images are expressed in hounsfield units. the hounsfield unit (hu) scale is a linear transformation of the original linear attenuation coefficient measurement into one in which the radiodensity of distilled water at standard pressure and temperature (stp) is defined as zero hounsfield units (hu), while the radiodensity of air at stp is defined as – 1000 hu. the corresponding hu value is therefore given by: hu w w = ⋅ − 10 3 m m m , (2) where m is the attenuation coefficient of the measured material, and mw is the attenuation coefficient of water. the x­ray attenuation coefficient is represented as ct numbers for a medical ct, calibrated to air with the value – 1000 and water with the value of 0 according to the hounsfield scale. grey­scale images are generally used to visualize the differences in x­ray attenuation. this process provides a digital 3d grey-scale representation (often called a tomogram). this can be quantitatively analyzed and virtually sliced in any direction, or specific constituents can be digitally colour­coded to visualize the 3d morphology. for example, bright colours (high values) have low porosity, and dark shades (low values) have high porosity in reservoir or host rocks with constant mineralogy and saturation (földes et al., 2004; wesolowski & lev, 2005; földes, 2011). measurements with x-ray ct are subject to various errors and image artifacts, including beam hardening, star­shaped, positioning errors, and machine errors. techniques used to minimize them have been discussed in full by van geet et al. 2000), ketcham & carlson (2001), and akin & kovscek (2003). 3.1. applied x-ray computed tomography a core sample of bcf (ib­4), about five m­long, was scanned at a high­resolution x­ray ct facility at the institute of diagnostic imaging and radiation oncology, university of kaposvar, hungary. the instrument operates at 120 kvp (peak kilovoltage), with a 250 mas (milliampere­seconds) current, and sampling intervals of 1.0 s. the lateral resolution was (0.1953 x 0.1953) mm2 with a 1.25 mm scan­slice thickness. the image reconstruction matrix was 512 x 512 pixels. the field of view (fov) was approximately 9.99 cm (abutaha et al., 2021a). scans were made using a modified dual­scanning approach (balazs et al., 2018). usually, rock samples are dried in a vacuum oven at temperatures of 120 to 210 °f (50 to 100 °c). drying is terminated when the samples reach a stable weight ( soeder, 1986). after six hours of vacuuming the sample, all pore water is removed, and ct measurements were acquired (scan of the dry core). the next phase constituted pumping water into the dried sample (saturation process). after an hour of relaxa­ tion, those slices that went under vacuum and saturated were re­scanned. ct images were stored in a dicom (digital and imaging communications in medicine) format. a dicom file contains the scanning parameters and the scanned object identification under different attributes in its metadata. of these metadata, the pixel spacing, and slice thickness g eologia c roatica abutaha et al.: continuous wavelet transformation to quantify small-scale cycles of petrophysical properties; a new approach applied in a potential ... 135 attributes are important for geoscientific applications as they record the dimension (in millimetres) of each voxel in the x, y, and z­directions. each ct number can be assigned a real­world distance (or depth), allowing ct number profiles to be constructed to calculate the depth and geometrical measurements. dicom images can easily be read by ‘classical’ 3d volume rendering software (abutaha et al., 2021a, 2021b, 2022). the laboratory guaranteed that the dicom files were free of any artifacts and that during the second scan, the same pixels were measured as during the first one. we have calculated the porosity values for each voxel of the image slices from both dry and saturated scans (moss et al., 1990). 4. continuous wavelet analysis (cwt) the time­frequency resolution problem caused by the heisenberg uncertainty principle exists regardless of the analysis technique used. simply, this principle states that one cannot know the exact time-frequency representation of a signal, i.e., one cannot know what spectral components exist at what instances of time. what one can know is the time intervals in which certain bands of frequencies exist, which is a resolution problem (polikar, 1999). by using an approach called multi­resolution analysis (mra) it is possible to analyze a signal at different frequencies with different resolutions (weng & lau, 1994; weng et al., 2017). every spectral component is not resolved equally, as was the case in the stft. the change in resolution is schematically displayed in fig. 3a, it is assumed that low frequencies last for the entire duration of the signal, whereas high frequencies appear from time to time as short bursts. this is often the case in practical applications. the wavelet analysis calculates the correlation between the signal under consideration and a wavelet function ψ(t), or the mother wavelet. the similarity between the signal and the analyzing wavelet function is computed separately for different time intervals and on different frequencies, resulting in a two­dimensional representation (scalogram). the continuous wavelet transform is defined as (addison, 2002; polikar, 1999): c y t twt s s x t t s dt ( , ) ( ) *= −   −∞ ∞ ∫1 (3) the transformed signal xwt (τ, s) is a function of the translation parameter τ and the scale parameter s. the mother wavelet is denoted by ψ; the * indicates that the complex conjugate is used in case of a complex wavelet. the signal energy is normalized at every scale by dividing the wavelet coefficients by 1/ s .this ensures that the wavelets have the same energy at every scale. the mother wavelet is contracted and dilated by changing the scale parameters. the scale s is used instead of the frequency for representing the results of the wavelet analysis. the translation parameter τ specifies the wavelet’s location in time (merry, 2005). by changing τ, the wavelet can be shifted over the signal as shown in fig. 3b. for constant scale s and varying translation τ, the rows of the time­scale plane are filled. varying the scale s and keeping the translation τ constant fills the columns of the time-scale plane. the elements in xwt (τ, s) are called wavelet coefficients. each wavelet coefficient is associated with a scale (frequency) and a point in the time domain. the scale s is inversely proportional to the frequency (shokrollahi et al., 2013; foster, 1996). thus, a large scale corresponds to a low frequency (giving global information about the signal), while small scales correspond to high frequencies (providing detailed signal information) (templeton, 2004). 5. methods the workflow followed is shown in fig. 4. the major aspects of the methodology are briefly addressed in three areas: pre­processing, wavelet implementation, and cross-correlation. 5.1. pre-processing due to the cooperation between the university of szeged, geochem, and the public limited company for radioactive waste management (puram), the raw data sets of a (5 m) vacuumed dry and saturated ct measurements of the bcf core sample were transferred to the university of szeged for further analyses application. only the texturally intact, unbroken parts of the scanned sample were used. five ct volume bricks of the core sample thus served as the basis of the present work (fig. 3). a 3d­nearest neighbour algorithm was used to build the 3d volumes of the five scanned core bricks. this process resulted in two hounsfield lattices, one for the vacuum dried and one for the saturated core volumes. the voxel porosities of the scanned slices were computed from the dual scan lattices subtraction. their refigure 3. a) multi-resolution time-frequency plane, b) continuous wavelet transform procedure. g eo lo gi a c ro at ic a geologia croatica 76/3136 sults were normalized by saturated hu values (moss et al., 1990; abutaha et al., 2021 a). although the output of computed tomography lends itself to straightforward interpretation, so-called scanning artifacts may obscure details of interest or cause the ct value of a single material to change in different parts of an image. the most encountered artifact in ct scanning is beam hardening. various methods have been developed to reduce or remove the effects of beam hardening (e.g., van geet et al., 2000; ketcham & carlson, 2001; akin & kovscek, 2003). one of these is the so­called “subset” ct volumes in which the image’s outer edges are removed, and only central volumes of the original three-dimensional images are used for quantitative analysis. determination of the hu intervals and calculating the relative percentages of the rock-forming components for the dry-vacuum scan was necessary for finding out and determining small­ scale layers (ct layers). so, as soon as the compositional data of the core sample was defined by layers, the dominant rock­forming components were loaned the name of the rock type. the hu intervals of bcf used in this paper, were defined by puram as follows: detrital fragments: < 2700 hu, fine siltstone: 2700 – 3150 hu, claystone: 3150 – 3300 hu, calcite and/or dolomite: 3300 – 3600 hu, and albite: > 3600 hu. 5.2. weighted wavelet z-transform (wwz) the wavelet transform shows great promise as a method for period analysis in time series, particularly for detecting the time evolution of the parameters describing periodic signals. however, when the wavelet transform is applied to unevenly sampled time series, the response of the wavelet transformation is often more dependent on irregularities in the number and spacing of available data than on actual changes in the parameters of the signal. in 1996 foster brought forward the idea of vector projection concerning the wavelet transformation process of non-equal-interval data. he pointed out that the analysis result could be greatly improved if wavelet transformation was taken as a vector projection. not only could a desired period be more accurately calculated, but the period’s stability could be disclosed. he adopted a morlete mother wavelet which fluctuates according to a term of the form eiz. the wavelet function used in fosters’ algorithm includes both a periodic, sinusoidal test function of the form exponential (eiw(t–t)) and a gaussian window function of the form (e–cw2(t–t)2) as a wavelet generating function for transformation ( f(z), see equation 4. f z e e ec t i t c ( ) ( ) ( ) ( ) /= – – – ––w t w t2 2 1 4 (4) the constant c determines how rapidly the analyzing wavelet decays; for example, a popular choice for c is 1/8p2. however, c could be treated as a parameter, where the wavelet transform would be characterized by three parameters instead of two. foster (1996) viewed the wavelet transform not just as a projection onto a set of trial functions, but also as a weighted projection (the weighted wavelet transform (wwt)) in equation 5. wwt n v v eff y x = −( ) ( ) 1 2 (5) neff the effective number of data points. vx is the weighted variation of the data, and vy is the weighted variation of the model function. a better estimate of the frequency of a significant peak would be obtained using a test statistic that was less sensitive to the effective number of data. fortunately, there is such a statistic for projections; the weighted wavelet z transform (wwz) (equation 6). z n v v v eff y x y = − − ( ) ( ) 3 2 (6) the ratio of the wwz to the wwt has been given in the equation (7). z wwt n v n v v n n s neff x eff x y eff eff( ) ( ) ( )( ) ( ) ( ) ( / ))= − − − = − − + 3 1 3 1 1 (7) the s/n is the estimated signal­to­noise ratio. as s/n is much less than 1, there is almost no difference between the wwz and the wwt, even in the limit of large data size n. thus, at low s/n, the figure 4. workflow. g eologia c roatica abutaha et al.: continuous wavelet transformation to quantify small-scale cycles of petrophysical properties; a new approach applied in a potential ... 137 wwz shares the drawbacks of the wwt. otherwise, on a moderate s/n ratio (�1), the wwz would significantly be improved than wwt. as the wavelet function fits data (signal), it weighs the data points by applying the sliding window function to the data. one point of the time-scale plane is computed for every scale and time (interval). thereby, the computations at one scale construct the rows of the time­scale plane, and the computations at different scales construct the columns of the time­scale plane. (foster, 1996; templeton, 2004). the (wwz) algorithm applied in this study is fixed at c = 1/72, corresponding to the wavenumber of 6 that is usually used in the equal (even) wavelet transform module. as the past 3.2 software package was used, we were able to handle the fluctuations of voxel porosity averages of ct layers over unequal depth distributions as signals over uneven time intervals. 5.3. cross-correlation we have calculated the cross-correlations of the continuous wavelet transform spectrum at six representative frequencies, using ibm spss statistical software, to quantify the similarities of the wavelet coefficients of porosity and rock­forming components on large, medium, and small-scale cycles contemporaneously and at various lagged values. the scales in both variables are defined at uniform frequencies, have a temporal dependency, and the sampling interval in one succession is the same in the other (have the same depth). two information items may emerge from such a comparison: the strength of the relationship between the two series and the lag or offset in time or distance between them at their position of maximum equivalence. the cross-correlation is simply the dot product of vectors x and y (davis, 1986). the number of data points the signal shifts is called the lag. the version of the cross-correlation for the matching position is given in equation 8. rm n xy x y n x x n y y = − − − ∑ ∑∑ ∑ ∑ ∑ ∑ * ( * ( ) )( * ( ) ) 2 2 2 2 (8) is the number of overlapped positions between the x and y series. the summations here are understood to extend only over the segments of the two sequences overlapped at the match position. rm, represents the cross-correlation for the matched position. the calculated cross­correlation coefficients series were delineated by the 5% significance level (the 95.0% confidence level). the zero­lag is often set where the origins of the two series are aligned; negative lags represent an arbitrary choice of the sense of the movement of one sequence past another. since the two series are not identical, the lags in which series a leads series b differ from those in which b leads a (fig. 5). in our case, wavelet coefficients of voxel­porosity lead the rock­forming components series on positive lags. the linear trend was removed as a pre-processing step of cross-correlation by subtracting a linear regression line from the transformed wavelet frequencies of the rock-forming components. 6. results 6.1. quantitative analyses of rock types based on the most frequent rock­forming constituent, we classified the stacked slices of ct volumes into 80 thin consecutive layers (abbreviated as l). the entire estimation’s grid number of the 80 ct layers is more than 40 million voxels. the statistical properties as well as the averaged compositional rock components of each defined ct layer, were calculated and are shown in table 1. those 80 layers were used as input data to implement the wavelet transformation. the layer-averaged compositional frequency percentages have proposed two major rock types; clayey siltstone and fine siltstone (table 1). the widest variability of the average frequency percentages is noticed in the fine siltstone. its range vari es from 39.24% to 64.84%. in comparison, the claystone variation range is significantly smaller (from 23.76% to 41.18 %). next, carbonate with an average frequency range extends from 7.15% to 23.41%. then, the smallest average percentage of the detrital fragments is 0.02%, and the largest is 2.22%. lastly, the albite average does not exceed 1% as a max, and its minimum is zero. the total averaged percentages of rock-forming components of each rock type are found to be as follows: in the fine siltstone rock type, for the detrital fragments, it is 0.44, about 55.4 for fine siltstone, 31.5 for claystone, 12.54 for carbonate, and 0.11 for albite. however, the percentages of the rock­forming components in the clayey-siltstone rock type are: 0.22 for the detrital fragments, 45.74 for the fine siltstone, 35.63 for the claystone, 18.16 for carbonate, and 0.2 for the albite. that is to say, the coarser compositional constituents’ percentages, such as detrital fragments and siltstone, dominate the fine siltstone rock type. in contrast, the finer components of claystone, carbonate, and albite show an occurrence in the clayey-siltstone rock type. 6.2. continuous wavelet transformation (cwt) results in fig. 6a, the wavelet power spectrum graph (scalogram) plots the absolute value of wavelet coefficients. those x and y axes numbers show that the cwt was computed at 400 translations (in 300 cm) and 100 scale locations on the translation­scale plane. the parameter scale in the wavelet analysis is similar to the scale used in maps. as in the case of maps, high scales correspond to a non-detailed global view (of the signal), and low scales correspond to a detailed view. similarly, in terms of frequency, low frequencies (high scales) correspond to global information about a signal (that usually spans the entire signal), whereas high frefigure 5. cross-correlogram of two dissimilar series (modified after devis (1986). shaded intervals indicate portions of a and b that are compared at two lag positions. zero lag positions indicate both series are aligned at their origin. g eo lo gi a c ro at ic a geologia croatica 76/3138 table 1. summary for general characters of ct layers defined, including averaged compositional frequency percentages of rock-forming components, average porosity mean, and standard deviations of porosity. bl oc k n o. la ye r n o . d ep th c m po ro si ty m ea n % st d. d ev averages of rock-forming components % sedimentary features d et rit al fra gm en ts fi ne si lts to ne cl ay st on e ca rb on at e a lb ite 1l1 l1 2.46 2.79 4.48 0.5 48.96 31.73 18.49 0.31 horizontal laminations, burrows, and fractures filled by calcite l2 6.63 2.46 4.09 0.17 42.7 35.63 20.94 0.29 l3 8.5 2.74 4.45 0.4 47.11 32.88 19.31 0.31 l4 11.8 2.70 4.37 0.23 42.69 34.29 22.37 0.42 l5 15.6 2.42 3.93 0.1 43.89 37.66 18.19 0.17 l6 16.6 2.66 4.40 0.41 44.96 33.12 21.06 0.46 l7 17.6 2.47 4.11 0.18 43.82 35.23 20.49 0.28 l8 19.5 2.61 4.25 0.25 44.43 34.22 20.77 0.35 lamination l9 20.6 2.93 4.61 0.61 56.56 28.71 13.92 0.2 l10 25 2.35 3.83 0.47 49.91 31.44 17.9 0.29 convolute bedding &desiccation cracks l11 27.5 2.22 3.68 1.02 59.52 26.39 12.85 0.22 l12 29.8 2.66 4.29 0.41 60.4 27.68 11.44 0.07 l13 35.5 2.23 3.63 0.1 46.81 37.54 15.48 0.061 l14 38.9 2.36 3.84 0.12 48.61 35.48 15.7 0.1 l15 45.9 2.86 4.55 0.24 45.26 34.45 19.8 0.25\ aleurolit intraclasts and albite nests l16 52.6 2.21 3.67 0.05 42.71 39.91 17.26 0.07 l17 62.5 2.13 3.60 0.13 43.83 37.41 18.52 0.11 l18 68.1 2.23 3.63 0.36 46.9 32.66 19.68 0.4 1l2 l19 69.5 2.30 3.65 0.03 43.09 39.27 17.54 0.07 sporadic albite nests; mass slides, fingerprints of traction currents l20 70.1 1.92 3.26 0.16 44 38.17 17.56 0.09 l21 74.5 2.13 3.59 0.04 43.23 38.8 17.68 0.07 l22 75.0 3.02 4.79 0.11 47.76 36.43 15.66 0.04 l23 77.3 2.08 3.41 0.04 43.11 39.43 17.35 0.07 l24 80.7 2.64 4.27 0.17 48.44 34.75 16.51 0.13 silt/dolomite intraclasts l25 84.2 2.13 3.50 0.53 50.52 30.79 17.79 0.36 l26 86.1 2.09 3.45 0.17 50.32 34.37 15.05 0.09 l27 87.5 2.44 3.95 0.87 49.19 29.39 19.87 0.68 l28 92.3 2.65 4.307 0.07 44.33 38.81 16.73 0.07 l29 95.8 2.16 3.53 0.26 46.35 34.77 18.49 0.12 l30 101 2.32 3.74 0.05 44.48 38.97 16.44 0.05 l31 106 2.53 4.03 0.08 41.85 38.4 19.52 0.15 homogeneous dark-red clayey-siltstone l32 112 2.28 3.69 0.21 45.16 34.51 19.86 0.25 l33 116 1.98 3.27 0.41 46.09 32.53 20.58 0.39 l34 120 2.08 3.37 0.17 48.63 35.13 15.97 0.097 l35 124 3.64 5.26 0.61 52.95 29.98 16.2 0.26 l36 130 2.31 3.72 0.17 49.07 35.09 15.57 0.1 l37 134 2.75 4.35 0.27 41.25 34.87 23.41 0.48 albite nests, silty intraclasts l38 138 2.488 3.92 0.14 46.55 36.33 17.04 0.08 2l1 l39 148 2.17 3.47 0.02 41.92 41.81 16.22 0.03 albite nests l40 167 2.05 3.33 0.05 46.61 39.02 14.28 0.03 l41 173 2.72 4.19 0.09 56.06 34.24 9.59 0.01 grain size tendency: fining upward, silty intraclasts l42 176 2.88 4.50 0.354 60.59 31.91 7.15 0.004 l43 177 2.87 4.64 0.06 55.7 35.43 8.79 0.01 l44 181 2.20 3.55 0.26 54.91 32.7 12.08 0.05 l45 181 2.15 3.39 2.22 58.34 28.2 11.18 0.06 silty intraclasts, albite nests, desiccation cracks l46 186 2.18 3.52 0.33 53.03 32.29 14.24 0.1 l47 192 2.41 3.82 0.21 56.54 32.58 10.63 0.03 l48 194 2.48 4.01 0.42 58.12 29.85 11.54 0.07 g eologia c roatica abutaha et al.: continuous wavelet transformation to quantify small-scale cycles of petrophysical properties; a new approach applied in a potential ... 139 quencies (low scales) correspond to detailed information about a hidden pattern in the signal. they typically appear from time to time as short bursts or spikes. therefore, three main frequency branches (cycles) are discerned in bold dashed lines in fig. 6a: small scale (5, 6.67, and 11 cm), intermediate scale (20, 30 cm), and large scale (66.67 cm). the solid black line marks what is known as the cone of influence. the cone of influence shows areas in the scalogram potentially affected by edge­effect artifacts. these effects in the scalogram arise from areas where the stretched wavelets extend beyond the edges of the observation interval. as such, within the inner region delineated by the black line, you are sure that the information provided by the scalogram is an accurate time-frequency representation of the data. outside the black line, information in the scalogram should be treated as suspect due to the potential for edge effects. the third dimension on the scalogram indicating the amplitude (power) of a particular frequency at a particular time, is represented as a colourmap (fig. 6a). the colourmap of the scalograms ranges from blue to red, and passes through the colours cyan, yellow, and orange. the bar on the bottom of the scalogram plot (fig. 6a) indicates the percentage of energy for each wavelet coefficient i.e., the darker red, the higher amplitude and more considerable value of wavelet coefficient. whereas the corresponding amplitude and energy of the great depression are represented by the blue colour. in fig. 6b, we detected the magnitude oscillation of the porosity scale cycles by plotting the cwt coefficients against the depth series changes. although the small­scale fluctuations are seen all through the core sample (fig. 6b), the oscillation has peaked at the lower parts of the core sample (deeper depths), i.e., the cycle of 6.67 cm. conversely, the intermediate oscillations are pretty strong in the upper parts of the core sample and reduce toward greater depths. this corresponds to the gradual colour changes in fig. 6a on the scalogram profile; for instance, the intense colour of the 30 cm scale has gradually changed from dark red at the shallower depths to almost orange at deeper depth. however, the large­scale cycle in fig. 6b predominates in the bl oc k n o. la ye r n o . d ep th c m po ro si ty m ea n % st d. d ev averages of rock-forming components % sedimentary features d et rit al fra gm en ts fi ne si lts to ne cl ay st on e ca rb on at e a lb ite 4l1 l49 195 3.05 4.74 0.544 47.604 32.289 19.192 0.371 dolomite intercalation, convolute bedding, vertically oriented calcite fillingsl50 199 2.510 4.07 0.048 41.532 39.763 16.612 0.045 l51 202 2.73 4.27 0.301 45.628 33.949 19.798 0.324 albite nests and aleurolit intraclastsl52 205 2.88 4.50 0.145 47.6 35.599 16.518 0.138 l53 210 2.75 4.37 0.53 48.214 32.048 18.892 0.315 l54 216 2.35 3.72 0.147 47.899 35.98 15.894 0.081 dolomite lenses and horizontal laminations l55 218 3.00 4.64 0.809 53.608 30.382 15.052 0.148 abundant albite nests on bedding surfaces l56 222 2.87 4.64 0.072 44.942 37.823 17.089 0.073 l57 224 2.44 3.94 0.0809 43.774 38.021 18.021 0.104 desiccation cracks, intraclasts, and convolutionsl58 233 2.86 4.56 0.341 43.597 33.103 22.488 0.471 l59 236 2.55 4.10 0.045 44.656 38.405 16.849 0.046 l60 237 2.89 4.51 0.062 47.02 37.349 15.504 0.064 abundant albite nests on bedding surfaces l61 239 2.20 3.54 0.326 53.564 31.943 14.041 0.126 l62 239 2.23 3.57 0.589 50.354 31.935 16.803 0.319 albite nests and aleurolit intraclasts l63 243 2.02 3.29 0.354 63.61 27.558 8.362 0.097 l64 246 2.30 3.74 0.92 64.843 23.764 10.409 0.065 l65 249 2.70 4.24 0.062 39.236 38.707 21.802 0.192 4l2 l66 254 2.46 3.91 0.082 48.115 37.178 14.572 0.052 albite nests & cracks l67 255 2.27 3.64 0.123 48.644 36.141 15.017 0.076 dominantly structureless, but bioturbation and aleurolite intraclast l68 257 2.60 4.10 0.497 48.266 31.281 19.537 0.419 l69 259 2.91 4.42 0.2396 49.636 33.639 16.03 0.16 l70 260 2.37 3.75 0.439 48.782 32.246 18.215 0.318 -l71 261 2.35 3.72 0.277 51.159 33.376 15.081 0.107 l72 263 2.36 3.73 0.084 51.264 36.645 11.98 0.027 l73 267 1.93 3.24 0.698 48.948 32.976 17.488 0.241 crossbedding with parallel set boundaries. synsedimentary fault, with abundant albite nestsl74 273 2.59 3.96 0.074 51.888 35.668 12.321 0.046 l75 280 2.51 4.02 0.282 54.474 29.63 14.937 0.262 crossbedding with parallel set boundaries. synsedimentary fault, with abundant albite nests l76 282 2.15 3.51 0.074 56.732 33.832 9.344 0.018 l77 283 3.12 4.83 0.282 54.501 32.326 12.78 0.11 l78 292 2.28 3.67 0.068 50.614 36.917 12.37 0.03 l79 294 2.830 4.36 0.192 44.045 35.051 20.416 0.296 calcite precipitations in the cracks l80 303 2.360 3.73 0.061 44.399 38.71 16.755 0.076 table 1. continued. https://en.wikipedia.org/wiki/amplitude g eo lo gi a c ro at ic a geologia croatica 76/3140 lower part of the core sample. so, in fig. 6a, its redness intensity has intensified (gotten darker) at the lower part of the core sample. to further validate the observations above, statistical characteristics of wavelet coefficients of the defined scale cycles were calculated and are summarized in table 2. in table 2, the 6.67 cm small­scale cycle shows the highest maximum value of wavelet coefficients (5.24) and the largest coefficient of variation (128.24%). the two peaked spikes at 202 and 250 cm depth in fig. 6a are almost the cause behind this exceptionally high coefficient of variation, as the wavelet coefficients are dispersed over a larger range. in other words, the wider the range (the difference between the min and max), the more the standard deviation is affected, and the greater the coefficient of variation. in comparison, on the 30 cm scale of the intermediate cycle, the coefficient of variation was the lowest (52.74%). this is relevant to the narrower range standard deviation spreads around (notice the max and min values) and the relatively high mean value (1.78). on the 20 cm scale cycle, it is evident that the standard deviation and mean are almost equal (1.277 and 1.24, respectively), so the variation of the coefficient was close to 100% (102.30%). back to fig. 6a, as was previously mentioned, the continuous wavelet transform analysis is based on integrating the multiplication results of a signal and a complex function (mother wavelet) over time. the product is non­zero when the signal falls in the region of support of the wavelet and zero elsewhere. this raises the question of why the transformation results of the continuous wavelet at the time interval (depth) of 148–176 (fig. 6a) is around zero at all scales. to answer the above question, we need to refer to table 1. it can be seen that the layers from l39 to l42 cover the exact depth interval of 148­176 cm. the coarser compositional constituents (detrital fragments and siltstone) were highest in l42 and l41, unlike the finer rock­forming components (claystone and carbonate) that were dominant in l40 and l39. the sedimentary signature of these layers (l39­ l42) takes the form of normal grading. so, the coarser sediments occur at the base (l42 and l41) and grade upward into progressively finer ones (l39 and l40). the influential occurrence of the claystone (authigenic and allogenic) in l40 and l39 (from the depth of 148 to 176 cm) might enhance a full or partial plugging of the pore throats (abutaha et al., 2022). this considerably reduces the average porosity (~2%) and decreases the pore volume variations (low std. dev < 3.5). therefore, the low average porosity in this portion of the core sample, delineated in l39 and l40, is basically the cause behind the weak porosity fluctuations (weak frequency component of the signal) at a depth of 148­176 cm. on the scale-translation plane, when the window width changes with increasing scale (decreasing frequency), the transform starts picking up the lower frequency components of the porosity signal. as soon as the wavelet window starts covering a depth of 148­176 cm, where the frequency is not a major signal component, the transformation product (wavelet coefficient) gives a (relatively) small value. this means that the frequency component in the signal has a small amplitude (see fig. 6a, b). however, when the wavelet window picks the higher frequencies (smaller scales), the transformation at the time interval of 148–176 cm would always be zero due to the minority or non­existent frequency component of the porosity signal. this explanation supports the zeros of the minimum wavelet coefficients for the smaller scale cycles (11, 6.67, and 5) and the non­zero minimum values for the larger ones (66.68, 30, and cm cycles) in table 2. thereupon, the wavelet coefficients’ variation is larger at the smaller scales and lower at the higher scales. 6.3 the cross-correlation of cwt in the large cycle (66.76 cm scale) in fig. 7, a positive relationship arises between wavelet coefficients of porosity and carbonate and porosity and detrital fragments series at zero lags. the correlation at these match positions is 0.4. however, in the intermediate cycle (30 cm), the highest correlation of the wavelet coefficients of porosity and rock­forming components occurs in two different lags; the first one is at the lag of 100 for porosity and siltstone, and porosity and carbonate, with r = 0.9 and r = 0.7 respectively. the second position is at lag 50 for wavelet coefficients of porosity with albite, porosity with claystone, and porosity with detrital fragments (r ≃ 0.9). furthermore, at the 20 cm scale, the porosity figure 6. a) power spectrum graph of the voxel porosity averages (scalogram), b) wavelet coefficient magnitude plot of voxel porosity averages. table 2. summary statistics of wavelet coefficients in each scale cycle defined. class. of cycle scale (1/frequency) summary statistics of wavelet coefficients average std.dev coef. of variation min max large 66.76 2.69 1.82 67.75% 0.39 5.23 medium 30 1.78 0.94 52.74% 0.49 3.3 20 1.24 1.27 102.30% 0 3.94 small 11 0.86 0.78 78.55% 0 2.31 6.67 1.03 1.3 128.24% 0 5.24 5 0.45 0.51 115.24% 0 2.42 g eologia c roatica abutaha et al.: continuous wavelet transformation to quantify small-scale cycles of petrophysical properties; a new approach applied in a potential ... 141 wavelet coefficient series correlates positively with the wavelet coefficients of claystone, albite, and detrital fragments at zero lags (r = 0.8). in the small­scale cycle (11 cm) in fig. 8, the strongest conformity between the wavelet coefficients series happens in porosity and claystone and porosity and detrital fragments series at zero lag (r = 0.7). the second highest correlation peak, r = 0.5, appears between the wavelet coefficients of porosity and siltstone series. in the 6.67 cm scale cycle at zero lag, the wavelet coefficients correlation exceeds 0.8(r ≃ 0.85) of the porosity and the albite series and decreases to 0.6 in the porosity and detrital fragments. otherwise, at the 5 cm scale, the porosity wavelet coefficients significantly correlate (r > 0.5) with the wavelet coefficients of all rock-forming components. 7. discussion the distinct peaks of cross­correlation at zero lags indicate that the measured wavelet coefficient series were contemporaneously correlated. their strong positive correlations suppose that both examined series respond similarly and simultaneously to other exogenous factors. for better understanding of those factors, we need to comprehend the linkage between the geological and petrophysical heterogeneity in each scale cycle. heterogeneity, which is the complexity and/or variability of the system property of interest in a space (fitch et al., 2015), does not necessarily refer to the overall system or individual rock unit, but instead it may be dealt separately for a particular parameter, such as porosity (frazer et al., 2005). in general, the heterogeneity, which reflects the variance of the pore distribution throughout rock types, is caused by sediment deposition, structural deformation, and diagenetic processes. by carefully comparing porosity and the standard deviation in table 1, it can be noticed that the porosity variation is highly consistent with the standard deviation values. since standard deviation is a tool to measure the data dispersion around the mean value, we could expect that the higher porosity average, the more heterogeneous pores volume, and the larger the standard deviation. then, the porosity wavelet’s oscillatory power increases. to give ground for this, we ought to consider the porosity classification of this core sample in particular. in a former study, the ct­layers were classified into three genetic groups based on data­mining techniques (abutaha et al., 2021a; 2022); macro­porosity, micro­porosity, and no­porosity clusters. the mean average of the matrix cluster porosity was 3.39%, 10.77% for the macro­porosity, and zero for the no­porosity. ratios of voxel-porosity of the three clusters were as follows: 30.37% for the matrix cluster, 14.65% for the macro­pores cluster, and 55% for the no­porosity cluster. comparing the claystone and carbonate ratios across the micro and macro-porosity clusters ilfigure 7. cross-correlogram resulting from the wavelet coefficients series of porosity and rock-forming components at large and medium scale cycles. g eo lo gi a c ro at ic a geologia croatica 76/3142 lustrates that the matrix cluster has the higher proportion of claystone and carbonate. diagenetic clay was also highly prospected to be found in the matrix cluster’s claystone component. authigenic minerals were influential in decreasing and increasing the pore volume ratio. for instance, smectite might swell and become free to move. this suggestion could explain the full or partial plugging of the pore throats. beyond that, collapse of smectite could lead to the adsorption of less water during the saturation phase, which together with particles released from the detrital deposit (i.e., albite and carbonate cement) structure, could create additional pore space. alternatively, the macro­porosity cluster has the lowest claystone content, albite is absent, and showed the highest detrital fragments occurrence. moreover, the pore spaces (macro-pores) might be created within the portion of the detrital fragment because of the larger grain size (abutaha et al., 2021b). eventually, the higher micro and macro­porosity rate, the greater the standard deviations. for a deeper discussion of the positive harmonizing oscillations of porosity, carbonate, and detrital fragments on the large scale­cycle, we’ve nominated two cases representing the highest cwt coefficients on the magnitude oscillation plot (fig. 6b) at depths of 218 cm and 233 cm. they are symbolized as l55 and l58, respectively in table 1. examination of the rock­forming components of l58, where the porosity average (2.86%) has demonstrated the high dispersion value of the standard deviation (4.56) shows that this clayey siltstone layer is composed of 0.3% detrital fragments (consisting of coarse siltstone or/and fine sandstone), 44% siltstone, 33% claystone, 22% carbonate, and approximately 0.5% albite. by way of explaining our example, we could propose three potential scenarios. at first, as the basement rocks in the source area of the bcf weathered and transported away, dissolved material was carried in solution and concentrated in the upper permian depositional basin by evaporation to provide a sodium­rich brine. added na ions into boda sediments were responsible for the partial to complete albitization of the detrital plagioclase. the ca ions released from plagioclase albitization were available to be removed in solution and react with hco3­ and mg2+ (milliken & land, 1991, 1993). the albitization of detrital plagioclase can therefore result primarily in the formation of calcite. some of the microporosity within the albite pseudomorphs is caused by volume reduction during albitization of the detrital plagioclase (morad et al., 1989). however, dissolving calcite (calcite cement) during periodic ephemeral inundations of the fluvial influx of the playa mudflat sediments of the bcf could be the primary reason for figure 8. cross-correlogram resulting from the wavelet coefficients series of porosity and rock-forming components at small scale cycles. g eologia c roatica abutaha et al.: continuous wavelet transformation to quantify small-scale cycles of petrophysical properties; a new approach applied in a potential ... 143 the cyclical pattern of the spatial porosity distribution. another possible explanation is the intergranular porosity associated with detrital grains, in which microporosity (matrix porosity) is reinforced to exist between different grains such as carbonate and sand/siltstone grains. one more assumption might be related to the so-called fracture porosity, in which void space is associated with unfilled extension fractures developed in grains and/or cement (adeyilola et al., 2022). in the l55 example, the averages of the rock-forming components, where the maximum porosity is 3%, illustrate an exceptionally high standard deviation (4.64), and are: 0.81% for the detrital fragments, 54% for the fine siltstone, 30% for the claystone, 15% for the carbonate and 0.15% for the albite. it is worth noting the discernibly high value of the detrital fragments, which represents the maximum value throughout the core sample. if we compare the detrital fragments and the standard deviation values, it is noticeable that the higher the detrital fragments, the higher the standard deviation (the increasing of the detrital fragments leads to larger standard deviations). to put it differently, the presence of the detrital fragments might increase the variance of pore volu me sizes, particularly in the matrix porosity medium. as an illustration, the pore opening between the detrital fragments and matrix grains caused by the dissolution of calcite cement in the initial stage of weathering would gradually connect and widen; thus, creating a larger pore volume and causing a higher standard deviation. conversely, the absence of detrital fragments increases the proportion of the claystonesiltstone components. in such a manner, microporosity predominantly occurs (low standard deviation). briefly, albitization of the detrital plagioclase, the dissolution of the calcite cement, and the detrital fragments abundance are seemingly the fundamental reasons behind the heightened porosity oscillation in the large scale-cycle. according to the 20 cm scale cycle, where the porosity oscillation shows good consistency with clay, albite, and detrital fragments fluctuations (fig. 7), l15 is illustrative as an example of the highest cwt coefficients on the magnitude oscillation plot (fig. 6b). the rock­forming components averages (table 1) in this layer are as follows: 45% of the fine siltstone, 34% of claystone, and 20% carbonate. the detrital fragments and the albite have almost an equivalent value; they are (0.24% and 0. 25%). to enhance our understanding of the concurrent occurrence of these variables, it is crucial to walk briefly through the (coupling albitization and illitization formation) process. that is to say, since the detrital fragments –support matrix grains, the rocks can retain more pore space (macro­porosity) (e.g., saigal et al., 1988). however, when sodium was diagenetically added from brines to the boda sediments (e.g., varga et al., 2005; mathe, 2015), the predominance of the clay mineral content resulted in the relatively great extent of albitization of the k­feldspar. the reaction of albitization (i.e., k­feldspar) is described below (chowdhury & noble, 1993; saigal et al., 1988; norberg et al., 2011): kalsi3o8 + na+ → naalsi3o8 + k+ the k­feldspar loses k+, gains na+, and transforms into albite. the different molar volumes of the k­feldspar and albite (the molar volume of k­feldspar is 109.1 cm3/mol, and that of albite is 100.2 cm3/mol), can generate an approximately 8% volume reduction after albitization of the k­feldspar occurred (norberg et al., 2011; wilkin et al., 1996). this expresses the feldspar albitization as a volume­reducing reaction (norberg et al., 2011), by which irregular intergranular pores often form between the replacement albite crystals. further, the allogenic claystone occurrence (clay minerals formed by depositional process), is expected here. pores hosted by clay minerals would be held rigidly by silt­sized dolomite and quartz crystals preventing the clays from compaction and ultimately preserve pores (adeyilola et al., 2022). in conclusion, as detrital fragments might support the macro-pores occurrence in the 20 cm cycle scale, the microporosity (intergranular pores) whether generated within the albitized feldspar grains, or preserved in the allogeneic claystone could promote the porosity oscillatory power and increase the heterogeneity of the pores volume distribution (high std. dev). the k­feldspar albitization is often coupled with the alteration of smectite to illite (diagenetic clay) as follows (boles & franks, 1979): k+ + al3+ + montmorillonite → illite + na+ + ca2+ + fe3+ + mg2+ + si4+ + h2o or k+ + montmorillonite → illite + na+ + ca2+ + fe3+ + mg2+ + si4+ +h2o the equations above demonstrate that the release na+, ca2+, fe3+, mg2+, and si4+. the si4+ would precipitate in the form of quartz. the alteration of kaolinite to illite would consume k+ (bjørlykke et al., 1986). the ca2+ and mg2+ would be involved in the carbonate cement evolution. however, the na+ could be evolved to precipitate diagenetic albite (albite cement) (e.g., varga et al., 2005; máthé., 1998; árkai et al., 2000). diagenetic albite cement could be precipitated as albite pore filling or preferentially along grain margins as overgrowths (máthé, 2015). once the grain margin is completely albitized, the margin of the grain would be composed of stable albite (min et al., 2019). this suggests that these types of cement (carbonate and albite) would be able to fully fill the textural composition’s pores; consequently, porosity is expected to be almost zero. notwithstanding, at the small cycle (6.67cm scale) the porosity oscillatory power heightens when albite fluctuation increases. this leads us to suppose two scenarios. the first is dissolution of the albite cement during late diagenetic processes. or, during the saturation phase, the difference between the pore pressure and the injected water pressure may force some small movable particles to get out from some semi­filled pore space. in this way, the pore volume increases in the exhausted pores (simon & anderson 1990; zhou et al., 1995; hayatdavoudi & ghalambor 1996; al­yaseri et al., 2015). along these lines, releasing albite particles from the pore volume could generate an additive micro pore space resulting from particle migration. those additive micro pores might cause a higher porosity measurement, resulting in a higher overall porosity oscillation (abutaha et al., 2022). at the 11 cm scale cycle, the porosity oscillation correlates positively with claystone, siltstone, and detrital fragments fluctuations. l35 is an instance of the highest cwt coefficients on the magnitude plot (fig. 6b) at a depth of 124 cm. here it is observed that this layer selected in the fine siltstone rock type (l35), comprises of 53% of fine siltstone, 30% of claystone, 16% of carbonate, 0.3% of albite, and around 0.6% of detrital fragments. it shows the highest porosity average (3.6%) and the greater standard deviation (5.26). due to the low percentages of both carbonate and clay, and the dominant occurrence of siltstone, as well as the relatively high detrital fragments ratio, one could expect a low g eo lo gi a c ro at ic a geologia croatica 76/3144 diagenetic process (if any) and low movement of particles during the saturation process. this suggests that this inherent porosity ought to be accurate. so, the porosity fluctuation might be related to the primary textural pore heterogeneity rather than the diagenetic processes (secondary porosity) (abutaha et al., 2022). simply put, porosity fluctuation in such a homogeneous rock compositional layer (see sedimentary feature column in table 1), could be attributable to the variability of the relevant rock-forming components. that is, as the siltstone component in this core sample was the significant parameter to getting the micro­pores to thrive, the detrital fragments, again, were fundamental in developing/controlling the macro-pores. thereupon, the standard deviation of porosity has shown the greatest value. intriguingly, in the small scale-cycle the porosity wavelet coefficients were positively correlated with all the rock­forming components. however, the multiple short spikes on the magnitude coefficients plot in fig. 6b are evoked by subsequent short, individual, events that happened at specific depths for short durations. for further explanation, we consider three major spikes as three different cases selected from the magnitude oscillation plot (fig. 6b); they are: l9, l49, and (l59­l60). going through the compositional components of the l9, it is apparent that this layer is similar to the example mentioned above (l35), where low carbonate and clay are aligned with the dominant occurrence of siltstone and detrital fragments (table 1). this is mostly spiking the porosity fluctuation to be 2.93% at a depth of 20 cm. in comparison with the l49, it is noticeable that the l9 has higher claystone, carbonate and albite (32%, 19% ,0.4%) and lower fine siltstone and detrital fragments (45%, 0 .5%). in addition, the presence of the convolute lamination structure suggests well mixed, poorly sorted grains so likely to have a low porosity sediment developed. nonetheless, it has the maximum porosity average (3%) and one of the highest standard deviation values (4.7). in fact, the presence of sedimentary struc tures in this core sample is more commonly interpreted as a type of heterogeneity. seemingly, internal void space in the layers’ sedimenta ry features might be the actual reason for developing the high average porosity of this ct layer. more precisely, the tight siltstone-claystone core samples preparation required drying out and heating in an oven before analyses to remove trapped moisture within the pores i.e., connate water, (the water that remains trapped in pores as the sediments compact and bind together). the drying process is terminated when the samples reach a stable weight, which indicates that all pore water has been removed (hinai et al., 2014). thereby, the vacuum-dry process altogether with macro-porosity resulted from the detrital fragments and the siltstone/claystone matrix porosity, could affect the available pore space and cause higher-porosity measurements, especially where connate water is expected to occur primarily. otherwise, l59­l60 encompass claystone, (~37%). the albite and the detrital fragments are almost zero, carbonate is around 16% and the siltstone average is around 45%. the abnormally high average of the claystone is predominantly attributed to the allogenic and diagenetic claystone. basically, clay minerals formed by depositional processes tend to have relatively higher porosity and lower permeability initially which is often lessened or eliminated by compaction. on the other hand, clay minerals formed by diagenetic processes reduce pore space and block pore­throats. however, in these samples, there is a positive trend with increasing clay minerals and porosity (adeyilola et al., 2022). so, this is either related to the pores hosted by clay minerals, or the sample preparation technique. drying in the oven at relatively high temperature (about 60 ℃) has been observed to induce potential microcracks and shrinkage in rocks containing clay minerals (hinai et al., 2014). since our technique involves saturating the samples fully with fluids that are not in chemical equilibrium with the clays, it is possible that the saturating fluids will fill the induced microcracks as well as causing the clay minerals to swell (i.e., smectite is collapsed). the swelling clay effect and microcracks artificially introduces some new pores which ultimately increase the porosity average and provide the spiking peak at a depth of 236­237 cm. 8. summary and conclusion the general purpose of this research is to investigate the smallscale repetitive oscillations of porosity distribution patterns in a 5 m silty­claystone core sample in the bcf using ct scan images. the methodology applied had three categories: pre-processing, wavelet implementation, and cross-correlation. in the pre­processing stage, we classified the stacked slices of ct volumes into 80 thin consecutive layers depending on the most frequent rock-form ing constituent. the statistical properties as well as the averaged compositional rock components of each defined ct layer were calculated. the porosity averages of the 80 ct layers were later used as input data to implement the continuous wavelet transformation. to locate the repetitive oscillations of porosity temporally and spatially, the fluctuations of porosity over unequal depth were handled as signals over uneven time intervals based on the wwz algorithm. thereafter, we were able to quantify the similarities of the wavelet coefficients of porosity and rock­forming components on all different scale cycles contemporaneously and at various lagged values, using cross correlation methods. lastly, the distinct peaks of cross-correlation at zero lags were interpreted by defining the highest magnitude oscillation of the cwt coefficients in terms of geological and petrophysical (i.e., porosity) heterogeneity. based on the procedures above, the following conclusions can be drawn: • by localizing the porosity high­energy spectrum within the cone of influence, three scale cycles were defined: small (5, 6.67, and 11 cm), intermediate (20, 30 cm), and large (66.67 cm). small­scale fluctuations were almost seen throughout the core sample. in comparison, the intermediate oscillations were pretty strong in the upper parts of the core sample (at a depth interval of 0­100 cm) and less strong toward greater depths. however, the large cycle predominated the lower part of the core sample (at a depth interval of 200­300 cm). • the fluctuation magnitude of the cwt coefficients at each scale cycle could be attributed to three main factors; sediment depositions, structural deformation, and diagenetic processes. for illustration: • at the large scale­cycle, the albitization of the detrital plagioclase, the dissolution of the calcite cement, and the detrital fragments abundance were the fundamental reasons behind the heightened porosity oscillation. • on the intermediate cycle (20 cm), the detrital fragments supported the macro-pores occurrence, however, those micro-porosity (intergranular pores) whether generated within the albitized feldspar grains, or preserved in the allogeneic claystone would promote the porosity oscillatory power. file:///y:/geologia%20croatica/geologia%20cro%202023/geologia_76-3/original/abutaha/javascript:; file:///y:/geologia%20croatica/geologia%20cro%202023/geologia_76-3/original/abutaha/javascript:; g eologia c roatica abutaha et al.: continuous wavelet transformation to quantify small-scale cycles of petrophysical properties; a new approach applied in a potential ... 145 • at the 11 cm scale cycle: the porosity fluctuation might be related to the primary textural pore heterogeneity rather than the diagenetic processes. thus, the siltstone component was significant to evolution of the micro­ pores, and the detrital fragments were fundamental in developing/controlling the macro-pores. • at the small cycle (6.67 cm scale), releasing albite particles from pore volumes during saturation process or even dissolving albite cement in late diagenesis could generate an additive micro pore space, which may increase the overall porosity oscillation. • at the 5 cm scale cycle: spiking porosity peaks were related to short, limited events such as sedimentary structures i.e., convolute lamination, or may even have been produced due to the data records glitches, including microcracks and shrinkage that occurred during the saturation process etc. • the diagenetic products must be figured out as a rule rather than an exception in studying the cyclical porosity behaviour, because the variability of the diagenetic process could modify or even obscure the original depositional porosity and reorganize the spatial pore volume distribution (pore system). in this study, the diagenetic processes i.e., albitizations, had an important influence to enhance the micro­ porosity occurrence, however dissolution processes were, more often than not, associated with macro-porosity. • the detrital fragments were the decisive rock component, improving the porosity oscillatory power relationships at all scales. thus, when the detrital fragments support matrix grains, the rocks could almost retain more pore space because of the larger grain size (coarse silt to fine sand particles). • moreover, the presence of the detrital fragments might increase the variance of pore volume sizes, particularly in the matrix porosity medium; so the higher the detrital fragments, the higher the standard deviation. conversely, the absence of detrital fragments increases the proportion of the claystonesiltstone components. in such a manner, microporosity predominantly occurs (low standard deviation). therefore, the cyclical porosity fluctuations at all scales would somehow concern the detrital fragments component (intraclasts); it provides a reference basis for the porosity cyclical behaviour. • sedimentary structures i.e., convolutions would enhance the micro-porosity abundance in a minor way. • in the fine siltstone rock type, where the coarser rock­forming components dominated the composition, i.e., detrital fragments and siltstone components are >50%, the textural heterogeneity would play an influential role to elevate the porosity oscillation magnitude. a future proposed endeavor is to analyze the spatial distribution of porosity and permeability at each scale cycle. this can add an essential insight into the prediction and understanding of the fluid flow behaviour at different scales of heterogeneity. acknowledgment we wish to acknowledge the public limited company for radioactive waste management (puram) for permitting the university of szeged to use its data sets in scientific research work. this research has been sponsored by the interdisciplinary excellence centre, institute of geography and earth sciences, long environmental changes research team, grants 20391­3/2018/ fekustrat and ginop­2.3.2­15­2016­ 00009 ‘icer’ of the european union and the state of hungary, ministry of human capacities, mecsekérc ltd and the european regional development fund. references abutaha, s.m., geiger, j., gulyás, s. & fedor, f. (2022): calculating the representative elementary volume of porosity using x-ray computed tomography: boda claystone formation core sample/hungary.– acta geologica slovaca, 14/1, 25–36. abutaha, s.m., geiger j., gulyás s. & fedor, f. (2021b): assessing the represen tative elementary volume of rock types by x-ray computed tomography (ct) – a simple approach to demonstrate the heterogeneity of the boda claystone formation in hungary.– geologos, 27/3, 157–152. doi: 10.2478/logos­2021­0018. abutaha, s.m., geiger j., gulyás, s. & fedor, f. (2021a): evaluation of 3d small­scale lithological heterogeneities and pore distribution of the boda clays tone formation using x­ray computed tomography images (ct).– geologia croatica, 74/3, 305–318. doi: 10.4154/gc.2021.17. addison, p. s. (2002): the illustrated wavelet transform handbook.– iop publishing ltd. doi: 10.1887/0750306920 adeyilola, a., nordeng, s. & hu, o. (2022): porosity and pore networks in tight dolostone–mudstone reservoirs: insights from the devonian three forks formation, williston basin, usa.– journal of earth science, 33/2, 462–481. doi: 10.1007/ s12583­021­1458­3 akin, s. & kovscek, a.r. (2003): computed tomography in petroleum engineering research.– in: mees, f., swennen, r., van geet, m. & jacobs, p. (eds): application of x­ray computed tomography in the geosciences. special publication, geological society of london, 215, 23–38. al­yaseri, a.z., lebedev, m., vogt, s.j., johns, m. l, barifcani, a. & iglauer, s. (2015): pore­scale analysis of formation damage in bentheimer sandstone with in­situ nmr and micro­computed tomography experiments.– j. petrol. sci., 129, 48–57. doi: 10.1016/j.petrol.2015.01.018. árkai, p., balogh, k., demény, a., fórizs i., nagy, g. & máthé, z. (2000): composition, diagenetic and post-diagenetic alterations of a possible radioactive waste repository site: the boda albitic claystone formation, southern hungary.– acta geologica hungarica, 43, 351–378. balázs, g.y.l., lublóy, é. & földes, t. (2018): evaluation of concrete elements with x­ray computed tomography.­ journal of materials in civil engineering, 30, 1­9. doi: 10.1061/(asce)mt.1943­5533.0002389 balla, z. (1987): tectonics of the beukkian (north hungary) mesozoic, relations to the west carpathians, dinarids.– acta geol. hung., 30/3–4, 257–287. barabás, a. & barabás­stuhl, á. (1998): stratigraphy of the permian formations in the mecsek mountains and its surroundings.– in: stratigraphy of geological formations of hungary. geological and geophysical institute of hungary, 187–215 p. (in hungarian) bjørlykke, k., aagaard, p., dypvik, h., hastings, d.s. & harper, a.s. (1986): diagenesis and reservoir properties of jurassic sandstones from the haltenbanken area, offshore mid­norway.– in: spencer, a.m. (ed.): habitat of hydrocarbons on the norwegian continental shelf. norwegian petroleum society, oslo, 275–286. boisson, j.y. (2005): clay club catalogue of characteristics of argillaceous rocks.­ in: radioactive waste management, oecd nuclear energy agency, 72 p. boles, j. r.& franks, s.g. (1979): clay diagenesis in wilcox sandstones of southwest texas: implications of smectite diagenesis on sandstone cementation.– j. sediment. res., 49, 55–70. chamoli, a. (2009): wavelet analysis of geophysical time series.– earth science india, 2/4, 258–275. chowdhury, a.h. & noble, j.p.a. (1993): feldspar albitization and feldspar cementation in the albert formation reservoir sandstones, new brunswick, canada.– mar. pet. geol.,10, 394–402. doi: 10.1016/0264­8172(93)90083­5 csontos, l. &vörös, a. (2004): mesozoic plate tectonic reconstruction of the carpathian region.– palaeogeogr. palaeoclimatol. palaeoecol. 210, 1–56. doi: 10.1016/j. palaeo.2004.02.033 davis, j. c. (1986): statistics and data analysis in geology.– john wiley & sons inc., new york. duchesne, m. j., moore, f., long, b.f. & labrie, j. (2009): a rapid method for converting medical computed tomography scanner topogram attenuation scale to hounsfield unit scale and to obtain relative density values.– engineering geology, 103, 100–105. doi: 10.1016/j.enggeo.2008.06.009 dutton, s.p. (2008): calcite cement in permian deep­water sandstones, delaware basin, west texas: origin, distribution, and effect on reservoir properties.– aapg bulletin, 92/6, 765–787. doi: 10.1306/01280807107 fedor, f., máthé, z., ács, p. & koroncz, p. (2018): new results of boda claystone research ­ genesis, mineralogy, geochemistry, petrophysics.– in: norris, s., neeft, e.a.c. & van geet, m. (eds.): multiple roles of clays in radioactive waste confinement. geological society, london, special publications, 482, doi: 10.1144/sp482.13 http://dx.doi.org/10.1007/s12583-021-1458-3 http://dx.doi.org/10.1007/s12583-021-1458-3 g eo lo gi a c ro at ic a geologia croatica 76/3146 fitch, p., lovell, m., davies, s., pritchard, t. & harvey, p. (2015): an integrated and quantitative approach to petrophysical heterogeneity.– marine and petroleum geology, 63, 82–96. doi: 10.1016/j.marpetgeo.2015.02.014 földes, t. (2011): integrated processing based on ct measurement.– journal of geometry and physics, 1, 23–41. földes, t., kiss, b., árgyelán, g., bogner, p., repa, i. & hips, k. (2004): application of medical computer tomography measurements in 3d reservoir characterization.– acta geologica hungarica, 47, 63–73. foster, g. (1996): wavelets for period analysis of unevenly sampled time series.– the astronomical journal, 112, 1709–1729. doi: 10.1086/118137 frazer, g., wulder, m. & niemann, k. (2005): simulation and quantification of the fine scale spatial pattern and heterogeneity of forest canopy structure: a lacu­ narity based method designed for analysis of continuous canopy heights.– forest ecology and management, 214, 65–90. doi: 10.1016/j.foreco.2005.03.056 grossman, a. & morlet, j. (1985): decomposition of functions into wavelets of constant shape and related transforms.­ in: streit, l., (ed.): mathematics, and physics, lectures on recent results, world scientific publishing, singapore. gurley, k. & kareem, a. (1999): application of wavelet transforms in earthquake, wind, and ocean engineering.– eng. struct., 21, 149–167. haas, j.& péró, c.s. (2004): mesozoic evolution of the tisza mega­unit.– international journal of earth sciences, 93, 297–313. hayatdavoudi, a. & ghalambor, a. (1996): controlling formation damage caused by kaolinite clay minerals: part i.– in: spe formation damage control symposium, society of petroleum engineers, spe­31118­ms. doi: 10.2118/31118­ ms. heismann, b.j., leppert j. & stierstorfer, k. (2003): density and atomic number measurements with spectral x­ray attenuation method.– journal of applied physics, 94, 2073–2079. doi: 10.1063/1.1586963 hinai, a. a., rezaee, r. & esteban, l. (2014): comparisons of pore size distribution: a case from the western australian gas shale formations.– journal of unconventional oil and gas resources, 8, 1–13. doi: 10.1016/j.juogr.2014.06.002 horváth, f. (1993): towards a mechanical model for the formations of the pannonian basin.– tectonophysics, 226, 333–357. doi: 10.1016/0040­1951(93)90126­5 hounsfield, g.n. (1973): computerized transverse axial scanning (tomography). description of system.– british journal of radiology 46, 1016–1022. doi: 10.1016/j. jhydrol.2010.02.029 jámbor, á. (1964): a mecsek hegység alsópermi képződményei [the early permian formations of the mecsek mts.].– mecsekérc ltd. archives, pécs, 127 p. ketcham, r.a. & carlson, w.d. (2001): acquisition, optimization and interpretation of x­ray computed tomographic imagery: applications to geosciences.– computational geosciences 27, 381–400. doi: 10.1016/s0098­3004(00)00116­3 konrád, g.y., sebe, k., halász, a. & babinszki, e. (2010): sedimentology of a permian playa lake: the boda claystone formation, hungary.– geologos 16, 27–41. doi: 10.2478/v10118­010­0002­1 labat, d. (2010): cross wavelet analyses of annual continental freshwater discharge and selected climate indices.– journal of hydrology. 385/1–4, 269–278. doi: 10.1016/j. jhydrol.2010.02.029 lázár, k. & máthé, z. (2012): claystone as a potential host rock for nuclear waste storage.– in: valaškova, m. & martynkova, g.s. (eds): clay minerals in nature – their characterization, modification and application. intechopen, london, 55–80. martelet, g., sailhac, p., moreau, f. & diament, m. (2001): characterization of geological boundaries using 1­d wavelet transform on gravity data: theory and application to the himalayas.– geophysics, 66, 1116–1129. doi: 10.1190/1.1487060 máthé, z. (1998): summary report of the site characterization program of the boda siltstone formation.– mecsek ore environment company, pécs, 4. máthé, z. (2015): results of mineralogical, petrological and geochemical investigation of boda claystone formation.– ph.d. thesis summary, elte department of petrology and geology, budapest, 1–6. [in hungarian] merry, r.j.e. (2005): wavelet theory and applications. literature study.– eindhoven university of technology, eindhoven, 50 p. milliken, k.l., & land, l.s. (1991): reverse weathering, the carbonate­feldspar system, and porosity evolution during burial of sandstones.– aapg bulletin, 75, 636. milliken, k.l. & land, l.s. (1993). the origin and fate of silt­sized carbonate in subsurface miocene–oligocene mudstones, south texas gulf coast.– sedimentology, 40, 107–124. doi: 10.1111/j.1365­3091.1993.tb01094.x min, h., zhang, t., li, y,zhao, s.h., li, j., lin, d. & wang, j. (2019): the albitization of k feldspar in organic­ and silt­rich fine­grained rocks of the lower cambrian qiongzhusi formation in the southwestern upper yangtze region, china.– minerals, 9/10, 620). doi:10.3390/min9100620 morad, s., bergan, m., knarud, r. & nystuen, j. p. (1990): albitization of detrital plagioclase in triassic reservoir sandstones from the snorre field, norwegian north sea.– journal of sedimentary research, 60/3, 411–425. doi: 10.1306/212f91ab­2b24­11d7­8648000102c1865d moss, r.m., pepin g.p. & davis, l.a. (1990): direct measurement of the constituent porosities in a dual porosity matrix.– in: sca conference, 9003. németh, t. & máthé, z. (2016): clay mineralogy of the boda claystone formation (mecsek mts., sw hungary).– open geoscience, 8, 259–274. doi: 10.1515/geo­ 2016­0024 norberg, n., neusser, g., wirth, r. & harlov, d. (2011): microstructural evolution during experimental albitization of k­rich alkali feldspar.– contrib. mineral. petrol., 162/3, 531–546. doi: 10.1007/s00410­011­0610­y ouadfeul, s. & aliouabe, l. (2011): automatic lithofacies segmentation using the wavelet transform modulus maxima lines combined with the detrended fluctuation analysis.– arabian journal of geosciences, 6/3, 625–634. doi: 10.1007/s12517­011­ 0383­7. ouadfeul, s. (2007): very fines layers’ delimitation using the wavelet transform modulus maxima lines (wtmm) combined with the dwt, seg srw.– université des sciences et de la technologie houari boumediene, antalya. ouadfeul, s., eladja, s. & aliouane, l. (2010): structural boundaries form geomagnetic data using the continuous wavelet transform.– arabian journal of geosciences, 5, 365–370, doi: 10.1007/s12517­010­0273. panda, m. n., mosher, c. c. & chopra a. k. (2000): application of wavelet transforms to reservoir­data analysis and scaling.– spe j. 5/1, 92–101. doi: 10.2118/60845­pa polikar, r. (1999): the wavelet tutorial. url: http://users.rowan.edu/ polikar/wavelets/wttutorial.html. potočki, k., gilja, g. & kunštek, d. (2017): an overview of the applications of wavelet transform for discharge and suspended sediment analysis.– tehnički vjesnik, 24/5, 1561–1569 prokoph, a. & barthelmes, f. (1996): detection of nonstationarities in geological time series: wavelet transform of chaotic and cyclic sequences.– computers & geosciences, 22, 1097–108. doi: 10.1016/s0098­3004(96)00054­4 remmy, r.r. & ferrell, r.e. (1989): distribution and origin of analcime in marginal lacustrine mudstones of the green river formation, south­central uinta basin, utah.– clays and clay minerals, 37, 419–432. doi: 10.1346/ccmn.1989.0370505 saigal, g.c., morad, s., bjørlykke, k., egeberg, p., k. & aagaard, p. (1988): diagenetic albitization of detrital k­feldspar in jurassic, lower cretaceous, and tertiary clastic reservoir rocks from offshore norway, i. textures and origin.– j. sediment. res., 58, 1003–1013. doi: 10.1306/212f8ee5­2b24­11d7­ 8648000102c1865d schneider, j., körner, f., roscher, m. & kroner, u. (2006): permian climate development in the northern peri­tethys area – the lodève basin, french massif central, compared in a european and global context.– paleogeography, palaeoclimatology, palaeoecology, 240, 161–183. doi: 10.1016/j.palaeo.2006.03.057 shokrollahi, e., zargar, g. & riahi, m.a. (2013): using continuous wavelet transform and short time fourier transform as spectral decomposition methods to detect of stratigraphic channel in one of the iranian south­west oil fields.– int. j. sci. emerg. technol, 5, 291–299. simon, d. & anderson, m. (1990): stability of clay minerals in acid.– in: spe for­ mation damage control symposium. society of petroleum engineers, spe­19422­ ms. doi: 10.2118/19422­ms.p.2 soeder, d.j. (1986): laboratory drying procedures and the permeability of tight sandstone core.– spe formation evaluation, 1, 16–22. doi: 10.2118/11622­pa templeton, m. (2004): time­series analysis of variable star data.– the journal of the american association of variable star observers, 32, 41–54. van geet, m., swennen, r. & wevers, m. (2000): quantitative analysis of reservoir rocks by microfocus x­ray computerised tomography.– sedimentary geology 132, 25–36. doi: 10.1016/s0037­0738(99)00127­x varga, a., raucsik, b., szakmány, g.y. & máthé, z. (2006): mineralogical, petrological and geochemical characteristics of the siliciclastic rock types of boda siltstone formation.– bulletin of the hungarian geological society, 136/2, 201–232. varga, a.r., szakmány, g.y., raucsik, b. & máthé, z. (2005): chemical composition, provenance and early diagenetic processes of playa lake deposits from the boda siltstone formation (upper permian), sw hungary.– acta geologica hungarica, 48, 49–68. doi: 10.1556/ageol.48.2005.1.2 weng, h.­y. & lau k. m. (1994): wavelets, period doubling, and time­frequency localization with application to organization of convection over the tropical western pacific.– j. atmos. sci., 51, 2523–2541. weng, i. k., gilja, g. & kunštek, d. (2017): an overview of the applications of wavelet transform for discharge and suspended sediment analysis.– tehnički vjesnik, 24/5, 1561–1569 wesolowski, j. r. & lev, h. m., (2005): ct: history, technology, and clinical aspects.– seminars in ultrasound, ct and mri, 26, 376–379. wilkin, r. t., barnes, h. l. & brantley, s. l. (1996): the size distribution of framboidal pyrite in modern sediments: an indicator of redox conditions.­ geochim. cosmochim. acta, 60, 3897–3912. doi: 10.1016/0016­7037(96)00209­8 withers, p. j., bouman, c., carmignato, s., cnudde, v., grimaldi, d., hagen, c.k., eric maire, e., manley, m., plessis, a. & stock, s. (2021): x­ray computed tomography.– nature reviews methods primers, 1/18, 1–21. doi: 10.1038/s43586­021­00015­4. yang, y., li y., yao j., zhang, k., iglauer, k., luquot l. & wang, z. (2019): formation damage evaluation of a sandstone reservoir via pore-scale x-ray computed tomography analysis.– journal of petroleum science and engineering, 183, 106356. doi: 10.1016/j.petrol.2019.106356. zhou, z., gunter, w. & jonasson r. (1995): controlling formation damage using clay stabilizers: a review.– in: annual technical meeting. petroleum society of canada, petsoc, 95–71. doi: 10.2118/95­71 https://doi.org/10.1016/j.juogr.2014.06.002 https://doi.org/10.1306/212f91ab-2b24-11d7-8648000102c1865d https://doi.org/10.1306/212f91ab-2b24-11d7-8648000102c1865d file:///y:/geologia%20croatica/geologia%20cro%202023/geologia_76-3/original/abutaha/javascript:; file:///y:/geologia%20croatica/geologia%20cro%202023/geologia_76-3/original/abutaha/javascript:; file:///y:/geologia%20croatica/geologia%20cro%202023/geologia_76-3/original/abutaha/javascript:; 2019 | 72/1 | 5–18 | 5 figs. | 2 tabs. | suppl. tab. 1 | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the increasing interest in lacustrine sediments since the early 1970s arose from new proof of their scientific and economic importance. lacustrine successions may preserve details of sedimentary processes from the earliest stage of lake genesis to its very end (binford & deevey, 1983; тalbot & kelts, 1989; engstrom et al., 2000; cohen, 2003; obradović & vasić, 2007). palaeolimnological data such as shoreline features, isotopic composition of authigenic carbonates, groundwater influences and changes in sediment grain size, structure and mineralogy, are useful in the reconstruction of lake-level changes in response to regional climate change (digerfeldt et al., 1993; fritz, 1996, 2008; hickman & white, 1989; almendiger, 1993). the economic importance of former lakes relies on the significant accumulations of solid and liquid hydrocarbons as well as of other valuable resources, such as diatomite and diatomaceous earth, sedimentary zeolite, clay (particularly bentonite), magnesite, dolomite, borates, including the recently discovered jadarite (stanley et al., 2007; whitfield et al., 2007). serbian lakes formed during the late oligocene and miocene in dominantly nnw–sse trending depressions along the old reactivated faults (obradović & vasić, 2007). sedimentation occurred in several tectonic, i.e. lake phases, which were related to different tectonic events, such as contraction, extension etc. (obradović & vasić, 2007). the majority of serbian lakes underwent two (e.g. valjevomionica, slanci, jadar, čačak-kraljevo, pranjane, mlava basin) or three (niš, aleksinac, kremna, etc), but rarely only one sedimentation cycle (kosjerić and leskovac basins) (obradović & vasić, 2007; fig. 1). the alternation of lake sediments with those formed in marsh or alluvial systems, sometimes with coal and/or oil shales resulted in highly diverse facies. the alternation of lake and marine sedimentation has been identified in the valjevo-mionica coastal area, at the ancient watering place of vračević (obradović & dimitrijević, 1978; obra do history of the belanovica (serbia) neogene lake basin inferred from petrological and geochemical data dragana marić*,1, danica srećković-batoćanin2, nebojša vasić2, marija radisavljević2 and tatjana đekić1 1 university of niš, faculty of natural sciences, višegradska 33, 18000 niš, serbia; (dragana.maric@gmail.com) 2 university of belgrade, faculty of mining and geology, đušina 7, 11000 belgrade, serbia doi: 10.4154/gc.2019.05 abstract the petrological and geochemical composition of neogene lacustrine successions and basement rocks of the belanovica basin in central serbia, were investigated in three exploration boreholes, drilled in the central part of the former lake. two boreholes accessed the basement, while the third one terminated in the lowermost neogene interval, composed of coarse-grained clastics. formation and diversification of the lake basin was influenced by strong syndepositional volcanic activity. the vertical distribution of selected elements from basal clastics (cr, ni, and mg) and from overlying lake sediments (ba, sr, na, k, etc.) indicates both the southern and northern margins of the basin, as potential source areas. the elemental concentrations are consistent with petrography. based on the derived data, a reconstruction of the basin history is presented. the lack of index fossils resulted in a less accurate stratigraphy and the need for further updating by employment of the fission-track low-temperature thermochronometers. additionally, outcrop studies and correlation with lake sediments in the valjevo-mionica basin is suggested. vić et al., 1997; obradović & vasić, 2007; krstić et al., 2012; neubauer et al., 2016). the manner of presentation of the serbian lakes is also highly diverse. lake basins were presented either according to their age and depressions where they have been developed (anđel ković et al., 1991; obradović & vasić, 2007) or were classified geographically, such as basins in northern, central and eastern serbia (krstić et al., 2003; dolić, 1986). according to krstić et al. (2003) the lake basins are remnants of a single lake (lake serbia), whereas other authors recognized many miocene lakes in mostly endemic and/or geographically isolated environments (e.g. marović et al., 2007; harzhauser & mandić, 2008). furthermore, the geochemistry including isotope studies of the serbian lakes is little known. the present study fills that gap by providing geochemical data that support results obtained by classic petrographic techniques. the objective in this study was to determine the range of concentrations of selected elements, which are indicative for the source of material: ultramafic rocks, or acid igneous, and metamorphic rocks. 2. regional geological setting the belanovica basin is part of the e-w trending valjevo-mionica-belanovica graben (marović et al., 2007). this two-part graben structure (belanovica in the east and valjevo-mionica segment in the west) was one of the major depressions within the peri-pannonian realm. subsequent movements along the diagonal faults led to the separation of individual basins (anđelković et al., 1991). the more intensive subsidence along the southernborder fault and asymmetrical inversion revealed a markedly asymmetrical belanovica basin (marović et al., 2007). the northern margin of the belanovica basin is formed by the brajkovac and bukulja mountains, composed of ~30–20 ma old granitoid rocks (knežević et al., 1994; cvetković et al., 2007) and devonian to carboniferous low-grade metamorphic rocks article history: manuscript received march 13, 2017 revised manuscript accepted november 28, 2018 available online fabruary 15, 2019 keywords: neogene, belanovica, lake basin, lithofacies, source rocks g eo lo gi a c ro at ic a geologia croatica 72/16 figure 1. neoalpine tectonic map of serbia 1:500.000 (marović et al., 2007) with locations of the lacustrine basins (obradović & vasić, 2007). legend: 1. slanci (slanci-grocka) basin; 2. valjevo-mionica basin; 3. jadar basin; 4. takovo-gomji milanovac basin; 5. čačak-kraljevo basin; 6. dobrinje-ježevac basin; 7. kosjeгić basin; 8. dragačevo basin; 9. pranjani basin; 10. kremna basin; 11. kopaonik basin and jarandol basin; 12. aleksinac basin; 13. senje-resava basin, 14. velika могаvа trough (niš, zaplanje, jelašnica, leskovac, ваrbeš, ražanj, popovac, braničevo and mlava basin) and 15. the position of figure 2 is represented by the rectangle. g eologia c roatica marić et al.: history of the belanovica (serbia) neogene lake basin inferred from petrological and geochemical data 7 (trivić et al., 2010; marović et al., 2007). its southern margin comprises jurassic ophiolites dominated by serpentinite, cretaceous flysch sediments and miocene volcanic and volcaniclastic rocks (fig. 2). according to marović et al. (1999) the studied basin is included in the serbian depositional province, which has been formed as a consequence of the early miocene extension and subsidence of the pannonian basin due to early-middle miocene collapse and core exhumation in the sava zone and tiszia (e.g. horvath et al., 2015). extension of the pannonian basin additionally increased the heat transfer that is presently still observed (matenco & radivojevic, 2012). 3. materials and methods all sedimentary rock samples were optically analyzed using a petrographic polarized microscope for transmitted light (leica dmlsp), connected to a leica dfc290 hd camera over the application las v4.1. major and trace chemical elements (including rees) contents were determined in 158 samples (76 from the borehole va-1, 54 from va-2 and 28 from va-3) in the sgs laboratory in lakefield (canada) using icp-aes analysis (icp 12b package), with samples repeated to ensure analytical consistency. samples were cleaned of weathered surfaces and crushed to <2 cm before being ground to a <200 μm in an agate mill retsch pm 200. accuracy and precision were estimated on the basis of standard rock materials and replicate analyses. contents for 12 elements used in discussion in all 158 samples and detection limits are given in supplementary table. procedures for manipulating data and drawing graphs were performed using sigma plot version 11.0 from systat software inc. san jose, ca, usa; available at: www.systatsoftware.com. granulometry was determined in epiclastic and sandy-gravelly loose sediments. the amount of sample for analyses depends on the grain size, thus about 100 g was taken from the former and figure 2. geological map of the broader area of the belanovica basin with borehole locations – detail from the basic geological map 1:100.000, sheet gornji milanovac (filipović et al., 1971). redrawn by m. radisavljević, using autocad 2014 software. g eo lo gi a c ro at ic a geologia croatica 72/18 figure 3. lithostratigraphic columns of boreholes. lithofacies are marked as in the text. solid lines connect the same levels. g eologia c roatica marić et al.: history of the belanovica (serbia) neogene lake basin inferred from petrological and geochemical data 9 up to 50 g from the finer-grained sediments. the qualitative-quantitative mineralogical composition was determined for four samples of epiclastites using the > 0.063 mm fractions, and in seven sand samples using fractions 0.125–0.25 and 0.25–0.50 mm. the highest dispersion of data is noted for quartz and rock fragment abundance in epiclastites. average values and standard deviation are presented for each constituent in table 1. fractions were prepared by wet-sieving techniques and analyzed afterwards under the binocular microscope (leica ez4d) and a polarised light microscope (leica dmlsp). the latter analysis required thin-sections prepared with xilol as the immersion liquid. micropalaeontological analyses included 36 samples washed and sieved under warm water (meshes 0.6–0.125 mm); discrete details of fossil molds required additional cleaning using 6% hydrogen peroxide. samples were analyzed by binocular microscope leica (up to 35 x magnification) and by reflected light microscope olympus bh2 (magnification up to 100 x). analyses were performed by rundić at the department for palaeontology of the faculty of mining and geology, university of belgrade. the content of caco3, as a proxy for carbonate content and precise determination of fine-grained clastites, was determined in 69 samples using a method of calcimetry and scheibler’s calcimeter. depending on the intensity of the sample reaction with diluted hcl, 0.5 g or 1 g of sample was ground in an agate vial. all analyses were performed at the department for mineralogy, crystallography, petrology and geochemistry of the faculty of mining and geology, university of belgrade. 4. results detailed mapping of cores from three exploration boreholes (va-1, va-2 and va-3) enabled determination of the basin infill and basement rocks (fig. 3). neogene sediments in the borehole va-1 overlie cretaceous flysch (212–335 m) and volcanic and volcaniclastic rocks in va-2 (268–296 m). the borehole va-3 did not access the basement. basement weakly lithified, moderate to well-sorted sandstones prevail in flysch clastites in va-1. sandstones are stratified in thin to moderately thick beds and consist of rock fragments that were derived from metamorphic rocks (including serpentinites) and limestones. flysch sediments in va-1 containing serpentinite/ultramafite fragments have a high heavy metal content, particularly ni (from 413 to 1429 ppm) and cr (from 106 to 992 ppm; supplementary table). volcanic and volcaniclastic rocks (ignimbrites) in borehole va-2 are products of volcanic activity dated to about 23 ma or younger (cvetković et al., 2000). among them, the quartz latites of hypocrystalline porphyritic texture, followed by fragments of lamprophyres, were the most abundant products originating from rudnik mountain (fig. 4a). heavy metal contents in the underlying rocks in va-2 range from 9.4–10.6 ppm (cr) and 4.4–5.2 ppm (ni). unit a the oldest neogene unit is the “basal coarse-grained clastites” (bcc; a in fig. 3). they consist of material derived from the volcanic complex and flysch, from triassic limestones or re-deposited volcaniclastic material (interval 212–162.5 m in va-1; 268 to 258 m in va-2 and 240–300 m in va-3). volcaniclastic material mostly consists of quartz (38.3–86.1%) and rock fragments (7.7–45.0 %). feldspar is subordinate (2.7–4.8%; table 1). fossil remains are lacking. unit b the transition from bcc into the overlying unit (b in fig. 3), ”marlstone and fine-grained clastites“, marks the package of laminated and clayey siltstones (at 165 m depth in va-1, and above 254 m depth in va-2) where the lacustrine mollusc fauna occurs for the first time in the succession (remains of freshwater gastropods – gyraulus sp., planorbarius sp., theodoxus sp.; fig. 4b). the amount of sand and gravel in this unit increases laterally along with the thickness of the unit itself (from 110 m in va-1 to 140 m in va-2). the given unit is typically represented in borehole va-1 where three lithofacies are distinguished: (1) fine-grained clastites (sandy-clayey siltstones prevail); (2) marlstone (compositionally uniform) and (3) fine-grained clastites and sands. horizontal lamination in lithofacies 1. and 2., determined by laminae of different granulometry, colour, composition and thickness is common. bioturbation occurs locally. the aforementioned lithofacies are weakly differentiated in borehole va-2, particularly when composed of marlstone. sands composed of well-rounded grains originating from volcanic complex and flysch sediments occur throughout the column of va-2, either as beds or as packages. the most abundant constituents of the sands are quartz (40.3–66.1%; table 1) and rock fragments (15.6–21.3 %). feldspar occurs in significant amounts (10.6–14.1 %), as well as muscovite (0.5–15.3%) and chlorite (1.6–15.7 %). finegrained clastites of different shades of brick-red colour, as well as green silty clays with carbonate nodules within the interval 195–180 m (see fig. 3) suggest subaerial exposure. unit b in column va-3 displays an upward decrease in grainsize and thickness. rounded pebbles in gravels were derived from clastites and altered volcanic rocks, while the finer-grained clastable 1. modal analyses of redeposited volcaniclastic (epiclastic) rocks and sands from borehole va-1. average values and standard deviation were calculated for each constituent in both rock types. the depth of samples in metres is given in brackets. minerals in % epiclastite sands 71 (188.5) 67 (184.5) 61 (171.3) 60 (167.0) avg. ± s.d. 5 (13.7) 11 (33.6) 17 (50.6) 23 (63.6) 26 (68.8) 32 (86.2) 35 (96.5) avg. ± s.d. quartz 86 40 45 48 55 ±18 63 66 64 66 59 40 57 59 ± 9 feldspar 6 30 9 7 13 ± 10 14 14 13 12 14 11 13 13 ± 1 rock fragm. 8 30 45 44 32 ±15 18 18 21 19 17 16 21 19 ± 2 calcite tr. tr. tr. tr. – 4 1 2 2 2 2 3 2 ± 1 muscovite – – – – – 1 1 – 1 5 15 4 4 ± 5 biotite – – 1 1 0.5 ± 0.5 – – tr. tr. tr. tr. tr. – chlorite tr. – – – – – – – – 2 16 2 2 ± 6 faunal fragm. tr. tr. – tr. – tr. – – tr. 1 tr. tr. – heavy min. – tr. tr. – – tr. tr. tr. tr. tr. tr. tr. – avg. – average; s.d. –standard deviations; tr. -trace; not detected. g eo lo gi a c ro at ic a geologia croatica 72/110 tites are composed of fragments of metamorphic rocks. sands display sedimentary structures of wave action (lenticular, wavy and flaser lamination). debris of mollusc remains (molds) is common. fine-grained clastites are calcite-clayey siltstones with 10–15% caco3 (table 2). deformational structures resulted from vertical and horizontal movements – small syn-sedimentary landslides. fresh-water organisms were identified in marlstones: carbonized flora, fish bones and scales, pyritized shell valves, ostracods (candona sp., amplocypris sp., hungarocypris? sp.) and gastropods. accumulated, i.e. gathered ostracods are common (fig. 4c). unit c the youngest recognized unit (c in fig. 3) is “sand, gravel, sandstone and fine-grained clastites“. its boundary with the previous unit is marked by basal conglomerates. a typical succession occurs within the va-1, from the surface to 50 m depth. sands are composed of quartz (63.2–66.1%), rock fragments (18–21.1%) and feldspars (12.8–14.0 %). muscovite is less abundant (up to 1 %) and chlorite and biotite are lacking (first three samples of table 1). sands in the deeper sections are of different granulometry and colour, and are organized in sets of trough cross or cross and horizontal lamination. elements of wave-action, such as wavy (ripple) lamination and weakly developed small-scale flaser or lenticular lamination, occur occasionally. in the upper part, thin to moderately thick beds of sandstone occur. intraformational fragments of sandstone, originating from a basal unit (b – marlstone and fine-grained clastites) reflects that the former sands were cemented by calcite. sandstones are considered to represent sub-litharenite, litharenite and arkose having similar composition to the underlying exposed sands (table 1). sand and gravel in va-2 alternate with fine-grained clastites. fine-grained clastites and marlstone display horizontal lamination. the content of freshwater bivalves (mytilopsis sp. and pisidium sp.), gastropods (melanopsis cf. decollata stoliczka, melanopsis ex gr. lyrata neumayr, gyraulus ex gr. pulici brusina, prososthenia sp., planorbarius sp.) and ostracods (hungarocypris sp. and candona sp.) is high. sands and gravels also comprise this unit in the va-3 column too. their boundary with the previous unit marks the sequence of yellowish-red coarse-grained gravels. variations in shades of red, yellow and grey colours through the overall unit reflect on relatively shallow, oxygen-rich environment. the lower part of the unit includes alluvial-lacustrine sequences (polymict gravels) with a notable presence of fragments from metamorphic rocks. sands vary in grain-size and display either horizontal or cross lamination. in finer-grained clastites, i.e. siltstones with more or less sandy fraction, one palaeosol horizon with two levels of carbonate concretions was detected. their structures reflect waveaction (wavy lamination and weakly developed flaser or even lenticular lamination). fossil material includes mollusc molds and well preserved terrestrial gastropods (e.g. clausilia sp.; fig. 4d). figure 4. a.photomicrograph of lamprophyre; b. theodoxus sp.; c. accumulated ostracods in marlstone at 195 m (va-3); d. clausilia sp. g eologia c roatica marić et al.: history of the belanovica (serbia) neogene lake basin inferred from petrological and geochemical data 11 5. discussion the natural concentration of elements in sediments is a function of the mineralogy of the source, the grain size and diagenetic processes/environment (moura & kroonenberg, 1990; hakstege et al., 1993; huisman & kiden, 1997). sedimentary rocks derived near sources may inherit the source rock signatures, particularly the fine-grained ones due to their less variable composition in comparison with sandstones (cullers, 2000). these signatures may be later modified by weathering, hydraulic sorting and diagenesis (cullers et al, 1987). the obtained geochemical data for all the exposed rocks support the results from the common petrographic techniques and indicate the source rocks. basement rocks flysch in va-1 contains rock fragments that were derived from metamorphic rocks (including serpentinites) and limestones. their high ni (413–1429 ppm) and cr (106–992 ppm; supplementary table) contents reflect the southwestern part of the studied area with serpentinite as the predominant source material. in terms of sedimentology, flysch corresponds to the distal parts of the fan in the bottom of the basin. considering the flysch sediments that outcrop about 15 km west of belanovica (e.g. around the volcanic mass of slavkovica) an albian-cenomanian age may be inferred. the presence of the brachiopod kingena concinna owen in the coarse-grained clastites with serpentinite fragments suggests a middle cenomanian age, whereas the limestone fragments originate from the upper albian and lower cenomanian carbonates (rabrenović et al., 2002; vasić et al., 2001). volcanic and volcaniclastic rocks (ignimbrites) in borehole va-2 are products of volcanism the evolution of which involves the mixing of ultrapotassic and calc-alkaline magmas, which has been very important and led to highly diverse products (cvetković et al., 2007; cvetković et al., 2001; prelević et al., 2001; prelević et al., 2004). the contents of cr (9.4–10.6 ppm) and ni (4.4.–5.2 ppm) in va-2 are notably lower than in va-1 (supplementary table). the average crustal abundance of ni is 0.01 %, while in sedimentary rocks it ranges from 5–90 μg/g (cox, 1995). the borehole va-3 did not access the basement but considering the data from the basic geological map corresponds to flysch sediments at the southern and to devonian-carboniferous metamorphic rocks at its northern margin (filipović et al., 1971). basement rocks display lithological and geochemical differences indicating petrological and stratigraphic differences of palaeorelief at the onset of lake formation. according to the depth distribution of the neogene basement the lake bottom was probably tilted towards the east, i.e. from va-1 to va-3. basin infill (neogene units) unit a (alluvial phase) the oldest neogene unit is basal coarse-grained clastites (bcc). as deposition took place during a partly developed lake basin the character of an alluvial system remained, particularly in va-3. bcc in va-1 and va-2 reflect the periodically high terrigenous input into the basin, most probably by torrential flows. it is composed of material derived from the volcanic complex and flysch, from triassic limestones or re-deposited volcaniclastic material. table 2. the caco3 % content in samples (for the long core samples, several powdered samples were made for analyses. such samples have the same number but are signed by uppercase letters, e.g. 13 a, 13 b, etc.). va-1 va-2 va-3 no. sample depth % caco3 rock determination after folk et al. (1970) no. sample depth % caco3 rock determination after folk et al. (1970) no. sample depth % caco3 rock determination after folk et al. (1970) 1 15 45.3 7.6 sandy-clayey siltstone 32 13 241.3 22.1 calcite-clayey siltstone 49 10 241.7 10.2 calcite-clayey siltstone 2 18 52.2 44.2 marlstone 33 14 243.3 11.9 calcite-clayey siltstone 50 13a 224.5 20.4 calcite-clayey siltstone 3 19 54.0 10.2 calcite-clayey siltstone 34 17 222.7 39.9 marlstone 50 13b 219.4 35.7 marlstone 4 20 55.6 10.2 calcite-clayey siltstone 35 18 214.8 25.5 calcite-clayey siltstone 50 13c 211.1 34.8 marlstone 5 21 59.1 12.7 calcite-clayey siltstone 36 19 201.7 42.5 marlstone 50 13d 204.3 37.4 marlstone 6 25 67.7 13.6 calcite-clayey siltstone 37 20 195.3 7.6 clayeysandy siltstone 50 13e 203.6 41.6 marlstone 7 27 70.8 16.1 calcite-clayey siltstone 38 25 160.4 11.9 calcite-clayey siltstone 50 13f 195.0 21.2 calcite-clayey siltstone 8 29 75.4 13.6 calcite-clayey siltstone 39 26 158.7 54.4 marlstone 50 13g 186.5 39.9 marlstone 9 30 79.9 17.0 calcite-clayey siltstone 40 28 140.7 16.1 calcite-clayey siltstone 50 13i 182.0 27.2 calcite-clayey siltstone 10 33 88.2 12.7 calcite-clayey siltstone 41 30c 130.2 10.2 calcite-clayey siltstone 50 13h 181.0 38.2 marlstone 11 36 99.5 14.4 calcite-clayey siltstone 41 30b 128.0 11.9 calcite-clayey siltstone 50 13j 177.6 31.4 calcite-clayey siltstone 12 37 103.4 17.0 calcite-clayey siltstone 41 30a 127.1 48.4 marlstone 50 13k 173.0 28.0 calcite-clayey siltstone 13 38 105.7 50.1 marlstone 42 33 110.5 17.0 calcite-clayey siltstone 51 14 168.2 13.6 calcite-clayey siltstone 14 39 108.8 48.4 marlstone 43 35 88.2 30.6 calcite-clayey siltstone 52 17 147.5 11.0 calcite-clayey siltstone 15 40 11.4 27.2 calcite-clayey siltstone 44 36c 84.0 43.3 marlstone 53 21 98.2 12.7 calcite-clayey siltstone 16 41 113.7 56.9 marlstone 44 36b 79.2 34.0 calcite-clayey siltstone 54 26 48.9 4.2 clayey siltstone 17 42 117.5 39.9 marlstone 44 36a 78.5 28.9 calcite-clayey siltstone 55 29 11.1 11.0 calcite-clayey siltstone 18 43 121.3 46.7. marlstone 45 38 66.6 25.5 calcite-clayey siltstone 19 44 123.8 39.9 marlstone 46 40 48.3 49.3 marlstone 20 45 128.2 51.8 marlstone 47 41 43.0 9.3 clayey siltstone 21 46 129.8 59.5 marlstone 48 43 26.1 42.5 marlstone 22 47 131.5 51.0 marlstone 23 48 134.5 42.5 marlstone 24 49 136.8 51.0 marlstone 25 50 138.8 39.9 marlstone 26 52 146.2 52.7 marlstone 27 53 151.5 20.4 calcite-clayey siltstone 28 54 153.2 81.5 limestone 29 56 157.8 16.1 calcite-clayey siltstone 30 57 159.0 50.1 marlstone 31 58 161.9 12.7 calcite-clayey siltstone g eo lo gi a c ro at ic a geologia croatica 72/112 the lower unit in va-1 corresponds to an alluvial system (not completely differentiated) and the upper part is re-deposited volcaniclastic rocks. the latter displays elements of debris flow, locally likely lahars, as being suddenly brought into the basin. in terms of sedimentology, the bcc corresponds to alluvial facies. sedimentology of bcc additionally confirms the lithological difference of lake margins and reflects to a different way of contribution (alluvial flows or lahars). subsidence during deposition of the bcc was more rapid than authigenic processes, such as lake infilling. although the fossil remains are lacking, their early middle miocene age may be supposed according to similar lithological succession in other basins, e.g. in the lake popovac (sant et al., 2017) and according to data from the basic geological map, sheet gornji milanovac (filipović et al., 1971). unit b (lacustrine phase) after deposition of the bcc the lake was completely formed. the transgression took place and the input of mediumand coarsegrained terrigenous material decreased, particularly in the central part of the lake (where the boreholes were drilled). coarser particles retained close to the margins forming the alluvial-lake and marginal-lake facies. slightly higher amounts of such material were brought into the area of boreholes va-1 and va-2, due to the proximity of the basin margin. finer-grained volcaniclastic material was synchronously brought into the basin revealing the first level of vitroclastic tuffs (see fig. 3). localized occurrences of tuff (~ 232 m in va-2) suggest that pyroclastic material arrived as lahars; otherwise a much broader area would be covered. according to krstić et al. (2012) lake basins in serbia are commonly lacking organisms with a calcium carbonate shell, as the lake water had to be acidic due to influence of volcanic activity. lake acidification is additionally supported by the early soil development along with the role of atmospheric precipitation (renberg, 1990). such a situation occurred during the period of deposition of the fine-grained clastites in shades of brick-red colour and green silty clays with carbonate concretions in alluvial sequences (interval 195–180 m in va-2), reflecting the periodic subaerial conditions. this unit (marlstone and fine-grained clastites) includes three lithofacies: (1) alluvial-lacustrine fine-grained clastites, (2) lacustrine marlstone, and (3) deltaic fine-grained clastites and sands. (1) the upward decrease of grain-size and dimension of sand bodies in all three boreholes indicate that material was brought by muddy, turbidity flows. the sand bodies resembled the shape of channels through which sand and gravel have been distributed. the coarsening and thickening upward pattern is caused by the increasing and coeval exhumation during extension of a source area (andrić et al., 2017). this gradually growing source area led to almost uni-directional sourcing of the basin (only from the north). the provenance zft (zircon fission tracks) age of 14.8 ± 0.8 ma (serravalian) for the coarse clastic sample from the belanovica basin, combined with some euhedral morphologies indicated the northern bukulja pluton as the source area (stojadinović et al., 2017). in the middle part of the basin the finest-grained, silty and clayey particles were deposited, and together with microcrystalline calcite allowed the formation of intrabasinal and lake facies, i.e. clastic-carbonate sediments. in terms of sedimentology this interval represents the alluvial-lacustrine facies. constituents of sands, well-rounded pebbles originating from the volcanic complex and flysch sediments, together with the high content of magnesium (mg) in va-3 (up to 2.16%) suggests the southern margin as the source area, as well as in va-2 (up to 8.43%; supplementary table). in va-1 both margins were included (fig. 5a). the contents of barium and strontium in fine-grained clastites is the highest in va-1 (in given unit average ba-115.20 ppm, sr-809.63 ppm; supplementary table). this reflects either different amount of calcite-clayey siltstones, i.e. calcite where ba2+ substitutes ca2+ or more involvement of granitic rocks that tend to contain higher concentrations of ba than the low-silica rocks (cullers, 1994). the slight increase of ba+sr in va-2 can suggest an increasing amount of fragments from lamprophyres or volcanic rocks with ba-bearing biotite at least (e.g. henderson, 1982; shaw & penczak, 1996). a low to moderate ba and ti-bearing mica is thought to have been formed by magmas in a subduction-enriched subcontinental lithospheric mantle (jaques et al., 1986; thompson et al., 1997). such an interpretation is consistent with the already mentioned interaction between lamprophyric and granitoid magmas (prelević et al., 2004). (2) during deposition of the marlstone lithofacies, which was the first truly intrabasinal facies, the basin was at least intermittently stratified. contents of ba+sr (500–2000 ppm) in the marlstones in va-2 in respect to na+k (0.6–1.1 %) could be explained by the substitution of k+ by ba2+ due to the presence of material from the southern margin (volcanic rocks; fig. 5b). the increase of ba+sr in respect to the almost uniform contents of na+k in marlstones in va-1 and va-2 is in agreement with the presence of hydrous mn and fe oxides, clay minerals and organic matter, which adsorb ba2+ at higher ph (wedepohl, 1978). the presence of sulfide (i.e. pyrite mineralization and carbonized flora) suggests periodically reduced conditions and an abundance of organic matter (recall the fig. 4c). a slight but progressive increase of th+u with the increase of na+k in va-1 and va-3 is in agreement with the increased contribution of material derived from the bukulja and brajkovac granites (fig. 5c). it should be mentioned that in the valjevo-mionica basin there was a noted increase in the concentrations of uranium in coaly interbeds in jelovik village (krstić et al., 2011). the high concentrations of th (3–16.7 ppm; supplementary table) could be due to the concentration of certain accessory minerals (e.g. zircon, monazite) in high-silica source rocks, i.e. granites (cullers, 1994). this element is (together with sc) considered to be the most useful ree for inferring source rock composition as its distribution is not severely affected by secondary processes (cullers, 1994). in va-2 these values do not correlate due to the variable abundance of fragments from felsic rocks and flysch clastites. (3) the final lithofacies (fine-grained clastites and sands) of this unit received material from both margins. alluvial systems from the south brought enormous amounts of coarsergrained terrigenous compounds (gravel and sand) into the basin resembling a deltaic model of deposition, i.e. alluvial-lake facies with well-evolved delta. delta comprised a delta plain, delta front and prodelta and it was intermittently flooded by a lake (constructive and destructive phase). unit c (alluvial-lacustrine phase) the youngest recognized unit is termed sand, gravel, sandstone and fine-grained clastites. intraformational fragments of sandstone, originating from unit b (marlstone and fine-grained clastites) shows that the former sands were cemented by calcite, most probably mobilized internally from the same unit. constituents of dominating sands and gravels in va-1 and va-2 imply almost exclusive origin from the northern margin, i.e. from metamorphic g eologia c roatica marić et al.: history of the belanovica (serbia) neogene lake basin inferred from petrological and geochemical data 13 and granitoid rocks. this could be a consequence of tilting to the south and uplift of the northern area leaving the bukulja and brajkovac massifs exposed to erosion. the high percentage of quartz relative to other minerals suggests that all the analyzed sandstones are most likely first cycle sediments, i.e. products of intense chemical weathering (cullers & podkovyrov, 2002). such an inference is additionally supported by the good correlation of boron (b) and lithium (li), particularly in va-2, where the lake depositional environment lasted the longest. in terms of sedimentology these sediments are considered to represent alluvial-lacustrine facies. local occurrences of lenticular bodies of sand or gravel on a metre to decametre scale resemble the channel forms by which particles were distributed. sands and gravels comprise this unit in column va-3, too. their boundary with the previous unit is marked by a sequence of yellowish-red coarse-grained gravels. the colour-variations throughout the unit reflect a shallow, oxygen-rich environment and the gradual closure of the basin. the presence of a palaeosol horizon with two levels of carbonate concretions in finer-grained clastites indicates periodic subaerial conditions and supports the previous conclusion. the lower part of the unit includes alluviallacustrine intervals (polymict gravels) with the notable presence of fragments from metamorphic rocks. the highest boron contents usually occur in sedimentary beds associated with volcanic activity, as in the volcaniclastic rocks in va-1 (unit b, interval 170–199m; values 87–172 ppm; supplementary table). in contrast, the tuffaceous rocks in va-2 display similar behaviour as sedimentary rocks in va-1 and va-3 – uniform b and slight increased li (fig. 5 d, e). most of the boron content of sands and sandstones can be attributed to the presfigure 5. distribution of selected elements in distinguished lithofacies. g eo lo gi a c ro at ic a geologia croatica 72/114 ence of tourmaline or to higher proportions of clay (harder, 1970). in finer-grained sediments its concentration varies inversely with grain size, thus the highest values are found in the finest fractions. boron, together with sodium is considered a good geochemical indicator of marine (saline) or fresh-water environments, as its content in sediment depends primarily on the type of rock involved (harder, 1970). the low na and uniform b reflects a lacustrine or fresh-water environment. age the availability of data on lacustrine sediments in serbia, regarding their age have until recently been scarce or only presented in local publications. the serbian lake sediments are older than the marine middle badenian, as they lie concordantly below it. as they are also overlain by marine deposits of late badenian/sarmatian age the lacustrine sediments were generally considered early to middle badenian. the valjevo-mionica-belanovica graben formed during the ottnangian-karpatian but later divided into the valjevo-mionica (west) and belanovica (to the east) basins (marović et al., 2007). index fossils are lacking in the belanovica lake sediments but the presence of freshwater melanopsis support their middle miocene age, as the earliest record of it dates back in the late early miocene (neubauer et al., 2016). the lack of marine sediments in the belanovica basin suggests that deposition ceased before the late badenian/ sarmatian when the valjevo-mionica basin was ingressed by marine water. the new data obtained for lake popovac reflect that the development of the serbian lakes started around 14.5 ma ago, in the langhian, which corresponds to the early badenian stage of the central paratethys (sant et al., 2017). the fission-track analysis is potentially useful for unraveling the age of the studied lacustrine sediments. 6. conclusions the belanovica lake developed during the neogene in the area between the brajkovac and bukulja mountains (granitoid and low-grade metamorphic rocks) to the north, and a broad area covered by albian-cenomanian flysch, jurassic ultramafics and the neogene volcanic mass of slavkovica to the south. alluvial and occasionally torrential flows coming from the south were responsible for the onset of deposition. the lake bottom dipped southeast periodically revealing parts of the lake sediments and exposing them to subaerial conditions. the alluvial-lacustrine and marginal-lacustrine facies retained close to the basin margin, whereas the finest-grained, silty and clayey particles arrived in the central and deepest part of the basin contributing there to the intrabasinal open-lacustrine facies. the alluvial flows from both margins contributed more than the synchronous volcanism to basin infilling, which itself was responsible for increasing the lake-water acidity. the flows from the single northern margin into the western area (va-1 and va-2) indicate the gradual closure of the basin. the eastern area (va-3) was frequently exposed to subaerial conditions giving rise to palaeosol development. the three-stage evolution of the belanovica basin, inferred from integrated chemical and petrographic data, was controlled by palaeorelief of the pre-neogene basement, erosion rate, and intensity of alluvial flows. the influence of volcanic activity should also be taken into consideration. lake sediments inherited signatures of the source rocks at the basin margins. the whole succession, lacking age-diagnostic fossils, was tentatively correlated with the middle miocene. tuffaceous rocks could hold the potential for unraveling the age of these lake sediments, as well as the fission-track low-temperature thermochronology. acknowledgment this research has been supported by the serbian ministry of science, project no 176019. the authors are indebted to colleagues from the company “ultra balkans d.o.o.” for permission to publish a part of their research results. we would like to thank the journal reviewers oleg mandić (vienna) and an unknown reviewer for their careful revision of the manuscript. their effort is gratefully acknowledged. we are indebted to ljupko rundić (belgrade) for providing palaeontological analysis. references almendinger, j.e. (1993): a groundwater model to explain past lake levels at parkers prairie, minnesota, usa. holocene, 3, 105–115. doi: 10.1177/ 095968369300300202 andriċ, n., sant, k., matenco, l., mandić, o., tomljenović, b., pavelić, d, hrvatović, h., demir, v. & ooms, j. (2017): the link between tectonics and sedimentation in asymmetric extensional basins: inferences from the study of the sarajevo-zenica basin.– marine and petroleum geology, 83, 305–332. doi: 10.1016/j.marpetgeo.2017.02.024 anđelković, m., eremija, m., pavlović, m., anđelković, j. & mitrović-petrović, j. (1991): paleogeografija srbije, tercijar [palaeogeography of serbia, tertiary – in serbian] (ed. m. anđelković), 237 p., beograd. binford, m.w. & deevey, e.s. (1983): palaeolimnology: an historical perspective on lacustrine ecosystems.– ann. rev. ecol. syst., 14/1, 255–286. doi: 10.1146/annurev.es.14.110183.001351 cohen, a.s. (2003). palaeolimnology: the history and evolution of lake systems.– oxford university press, new york. cox, p.a. (1995): the elements on earth.– oxford university press, 287 p. cullers, r.l. (1994): the chemical signature of source rocks in size fractions of holocene stream sediment derived from metamorphic rocks in the wet mountains region, colorado, usa.– chemical geology, 113, 327–343. doi: 10.1016/00092541(94)90074-4 cullers, r.l. (2000): the geochemistry of shales, siltstones and sandstones of pennsylvanian-permian age, colorado, usa: implications for provenance and metamorphic studies.– lithos, 51, 181–203. doi: 10.1016/s0024 4937(99)00063-8 cullers, r.l., barrett, t., carlson, r. & robinson, b. (1987): rare earth element and mineralogic changes in holocene soil and stream sediment: a case study in the wet mountains, colorado, usa.– chem. geol., 63, 275–297. doi: 10.1016/0009-2541(87)90167-7 cullers, r.l. & podkovyrov, v.n. (2002): the source and origin of terrigenous sedimentary rocks in the mesoproterozoic ui group, southern russia.– precambrian research, 117, 157–183. doi: 10.1016/s0301-9268(02)00079-7 cvetković, v., prelević, d. & pécskay, z. (2000): lamprophyric rocks of the miocene eruptive complex (central serbia, yugoslavia).– acta geologica hungarica, 43/1, 25–41. issn 0236-5278 cvetković, v., poli, g., christofides, g., koroneos, a., pécskay, z., resimić-šarić, k. & erić, v. (2007): the miocene granitoid rocks of mt. bukulja (central serbia): evidence for pannonian extension-related granitoid magmatism in the northern dinarides.– european journal of mineralogy, 19, 513–532. doi: 10.1127/0935-1221/2007/0019-1736 cvetković, v., poli, g. & prelević, d. (2001): eruptive history and low-pressure evolution of the early miocene borač eruptive complex (central serbia).– in: downes, h. & vaselli, o. (eds.): tertiary magmatism in the dinarides balkan peninsula, acta vulcanologica, 13/(1/2), 127–143. digerfeldt, g., almendinger, j.e. & bjorck, s. (1993): reconstruction of past lake levels and their relation to groundwater hydrology in the parkers prairic sandplain, west-central minnesota.– palaeogeography, palaeoclimatology, palaeoecology, 94, 99–118. doi: 10.1016/0031-0182(92)90115-l dolić, d. (1986): neki aktuelni problemi daljeg istraživanja tercijarnih naslaga sr srbije [some actual problems for further studies of tertiary deposits in sr serbia].– xi kongres geologa jugoslavije, 2, 61–68, tara. engstrom, d.r., fritz, s.c., almendinger, j.e. & juggins, s. (2000): chemical and biological trends during lake evolution in recently deglaciated terrain.– nature, 408, 161–166. doi: 10.1038/35041500 filipović, i., pavlović, z., marković, b., rodin, v., marković, o., gagić, n., atin, b. & milićević, m. (1971): osnovna geološka karta sfrj 1:100.000, list gornji milanovac l 34-137 [basic geologic map of sfry 1:100 000, gornji milanovac sheet].– savezni geološki zavod, beograd. g eologia c roatica marić et al.: history of the belanovica (serbia) neogene lake basin inferred from petrological and geochemical data 15 folk, r.l., andrews, p.b. & lewis, d.w. (1970): detrital sedimentary rock classification and nomenclature for use in new zealand, new zealand.– journal of geology and geophysics, 13/4, 937–968. doi: 10.1080/00288306.1970.10418211 fritz, c.s. (1996): palaeolimnological records of climatic change in north america.– limnology and oceanography, 41/5, 882–889. doi: 10.4319/lo.1996.41.5.0882 fritz, c.s. (2008): deciphering climatic history from lake sediments.– journal of palaeolimnology, 39, 5–16. springer. doi: 10.1007/s10933-007-9134-x hakstege, a.l., kroonenberg, s.b. & van wijck, h. (1993): geochemistry of holocene clays of the rhine and mouse rivers in the central-eastern netherlands.– geol. mijnbouw, 71, 301–315. harzhauser, m. & mandić, o. (2008): neogene lake systems of central and south-eastern europe: faunal diversity, gradients and interrelations.– palaeogeography, palaeoclimatology, palaeoecology, 260, 417–434. doi: 10.1016/j.palaeo.2007.12.013 harder, h. (1970): boron content of sediments as a tool in facies analysis.– sedimentary geology, 4/(1–2), 153–175. doi: 10.1016/0037-0738(70)90009-6 henderson, p. (1982): inorganic geochemistry.– pergamon press, oxford, u.k., 353 p. huisman, d.j. & kiden, p. (1997): the geochemical record of upper cenozoic sedimentation history in the southern netherlands.– geol. mijnbouw, 76, 277–291. doi: 10.1023/a: 1003212721020 hickman, m. & white, j.m. (1989): late quaternary palaeoenvironment of spring lake, alberta, canada.– journal of palaeolimnology, 2, 305–317. doi: 10.1007/ bf00195478 jaques, a.l., lewis, c.d. & smith, c.b. (1986): the kimberlites and lamproites of western australia.– geol-surv. western australia bull., 132, 268 p. jovanović, o., grgurović, d. & zupančič, n. (1992): kontinentalno-jezersko i marinsko-brakični neogen valjevskog i tamnavskog basena [continental-lacustrine and marine-brackish neogene in the valjevo and tamnava basins].– vesnik geozavoda, beograd. knežević, v., karamata, s. & cvetković, v. (1994): tertiary granitic rocks along the southern margin of the pannonian basin.– acta mineralogica-petrographica, szeged, 35, 71–80. krstić, n., dumurdžanov, n., olujić, j., vujnović, l. & jankovićgolubović, j. (2001): interbedded tuff and bentonite in the neogene lacustrine sediments of the central part of the balkan peninsula. a review.– acta vulcanologica, 13, 91–99. krstić, n., savić, l., jovanović, g. & bodor, e. (2003): lower miocene lakes of the balkan land.– acta geologica hungarica, 46, 291–299. doi: 10.1556/ ageol.46.2003.3.4 krstić, n., savić, l. & jovanović, g. (2012): the neogene lakes on the balkan land.– annales géologiques de la peninsule balkanique, lxxiii, 37–60. doi: 10.2298/gabp1273001r marović, m., krstić, n., stanić, s., cvetković, v. & petrović, m. (1999): evolucija neogenih sedimentacionih prostora centralnih delova balkanskog poluostrva [evolution of the neogene sedimentation area in the central balkan peninsula].– radovi geoinstituta, 36, 25–94, beograd. marović, m., toljić, m., rundić, lj. & milivojević, j. (2007): neoalpine tectonics of serbia.– serbian geological society, series monographie, 71–78. doi: 10.2298/gabp1273099c matenco, l. & radivojevic, d. (2012): on the formation and evolution of the pannonian basin: constraints derived from the structure of the junction area between the carpathians and dinarides.– tectonics, 31/6, tc6007. doi: 10.1029/ 2012tc003206 moura, m.l. & kroonenberg, s.b. (1990): geochemistry of quaternary fluvial and eolian sediments in the southeastern netherlands.– geol. mijnbouw, 69, 359– 373. obradović, j., djurdjević-colson, j. & vasić, n. (1997): phytogenic lacustrine sedimentation–oil shales in neogene from serbia, yugoslavia.– journal of palaeolimnology, 18, 351–364. obradović, j. & dimitrijević, r. (1978): piroklastične stene sa analcimom iz “slanačke serije” beogradskog dunavskog ključa [pyroclastic rocks with analcime from the slanci series of the danube river band (dunavski ključ) near belgrade – in serbian].– annales géologiques de la peninsule balkanique, xlii, 483–492, beograd. obradović, j. vasić, n. (2007): neogene lacustrine basins from serbia.– monographs, dclxii, serbian academy of sciences and arts, 310 p. pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.– basin research, 13, 359– 376. doi: 10.1046/j.0950-091x.2001.00155.x prelević, d., cvetković, v. & foley, s.f. (2001): composite igneous intrusions from serbia: two case studies of interaction between lamprophyric and granitoid magmas.– in: downes, h. & vaselli, o. (eds.): tertiary magmatism in the dinarides balkan peninsula: acta vulcanologica, 13/1-2, 145–157. doi: 10.1400/ 19071 prelević, d., foley, s.f., cvetković, v. & romer, r.l. (2004): origin of minette by mixing of lamproite and felsic magmas in veliki majdan, serbia.– journal of petrology, 45/4, 759–792. doi: 10.1093/petrology/egg109 rabrenović, d., vasić, n., mitrović-petrović, j., radulović, v., radulović, b. & srećković-batoćanin, d. (2002): the middle cenomanian basal series of planinica, western serbia.– annales géologiques de la peninsule balkanique, 64 (2001), 13–43. doi: 10.2298/gabp0264013r renberg, i. (1990): a 12,600 year perspective on the acidification of lilla oresjon, southwest sweden.– phil. trans. roy. soc. lond., b 327, 357–361. sant, k., mandic, o., rundić, l., kuiper, k.f., & krijgsman, w. (2017). age and evolution of the serbian lake system: integrated results from middle miocene lake popovac.– newsletters on stratigraphy, 51/1. doi: 10.1127/nos/2016/0360 shaw, c.s.j. & penczak, r.s. (1996): bariumand titaniumrich biotite and hlogopite from the western and eastern gabbro, coldwell alkaline complex, northwestern ontario.– the can. mineral., 34, 967–975. stanley, c., jones, g., rumsey, m., blake, c., roberts, a., stirling, j., carpenter, g., whitfield, p., grice, j. & lepage, y. (2007): jadarite, linasib3o7(oh), a new mineral species from the jadar basin, serbia.– eur. j. mineral., 19, 575–580. doi: 10.1127/0935-1221/2007/0019-1741 stojadinović, u., matenco, l., andriessen, p., toljić, m., rundić, lj. & ducea, m. (2017): structure and provenance of late cretaceous–miocene sediments located near the ne dinarides margin: inferences from kinematics of orogenic building and subsequent extensional collapse.– tectonophysics, 710–711, 184–204. doi: 10.1016/j.tecto.2016.12.021 talbot, m.r. & kelts, k. (1989): the phanerozoic records of lacustrine basins and their environmental signals.– palaeogeography, palaeoclimatology, palaeoecology, 70/1–3, 1–5. elsevier. doi: 10.1016/0031-0182(89)90076-x thompson, r.n., velde, d., leat, p.t., morrison., m.a., mitchell, j.g., dickin., a.p. & gibson., s.a. (1997): oligocene lamproite containing an alpoor, ti-rich biotite, middle park, northwest colorado, usa.– mineral. mag., 61, 557–572. doi: 10.1180/minmag.1997.061.407.08 trivić, b., cvetković, v., smiljanić, b. & gajić, r. (2010): deformation pattern of the palaeozoic units of the tethyan suture in the central balkan peninsula: a new insight from study of the bukulja-lazarevac palaeozoic unit (serbia).– ofioliti, 35/1, 21–32. doi: 10.2298/gabp1374047v vasić, n., kostić, m., durić, s. & rabrenović, d. (2001): visoko magnezijumske smektitske gline u bazalnoj seriji alb-cenomana planinice (zapadna srbija) [high-smectite clays in the basal albian-cenomanian series in planinica (western serbia)].– mineralogija, godišnjak jam, 3, 78–84. beograd. wedephol, k.h. (1978): handbook of geochemistry. ii/4, springer-verlag-berlin– heidelberg-new york. whitfield, p., page. l.y., grice, j., stanley, c., jones, g., rumsey, m., blake, c., roberts, a., stirling, j. & carpenter, g. (2007): linasib3o7(oh) – novel structure of the new borosilicate mineral jadarite determined from laboratory powder diffraction data.– acta crystallographica, b63, 396–401. doi: 10.1107/50108768107010130 g eo lo gi a c ro at ic a geologia croatica 72/116 cr (ppm) ni (ppm) mg (%) ba (ppm) sr (ppm) th (ppm) sc (ppm) th/sc u (ppm) na (%) k (%) b (ppm) li (ppm) limit(s) 1ppm 1% 1ppm 1% 0.01%15% 5ppm 1% 0.5ppm0.1% 0.1ppm1000 0.5ppm 1% 0.05ppm1% 0.01%15% 0.01%15% 10ppm-1% 1ppm 1% interval (in m): from – to va -1 b 65.40 66.40 41.50 65.30 1.14 112.20 220.00 6.80 7.20 0.94 1.27 0.02 0.33 20.00 49.80 69.85 70.85 49.00 82.20 1.28 147.60 515.00 8.30 8.10 1.02 1.77 0.03 0.37 20.00 57.80 78.00 79.00 55.20 93.30 1.30 115.40 451.00 8.60 8.70 0.99 1.61 0.02 0.34 15.00 53.30 81.30 82.30 50.80 78.80 1.18 108.40 358.00 6.20 7.30 0.85 1.32 0.03 0.34 13.00 49.50 85.70 86.70 29.60 41.10 0.66 115.80 129.00 4.70 5.00 0.94 0.83 0.04 0.24 11.00 28.30 90.20 91.20 40.30 63.60 0.97 81.20 229.00 5.30 6.00 0.88 1.01 0.03 0.27 12.00 41.10 94.70 95.70 29.00 40.20 0.64 89.80 176.00 3.90 4.00 0.97 0.82 0.03 0.16 11.00 23.00 99.50 100.50 46.40 75.30 1.01 97.60 356.00 5.70 5.90 0.96 1.20 0.03 0.23 13.00 43.60 103.70 104.70 44.60 77.40 1.06 122.60 466.00 6.00 5.90 1.01 1.12 0.04 0.28 18.00 46.00 112.70 113.70 52.60 96.40 1.21 282.80 1666.00 5.50 3.80 1.44 2.56 0.06 0.22 25.00 50.80 117.30 118.30 91.00 131.00 1.39 179.80 1017.00 6.20 4.30 1.44 1.86 0.07 0.23 16.00 45.20 121.20 122.20 34.70 75.90 0.84 207.20 1379.00 4.50 2.60 1.73 2.22 0.07 0.16 13.00 27.20 125.30 126.30 69.40 95.40 1.21 173.00 1140.00 5.60 3.50 1.60 1.85 0.07 0.18 12.00 37.70 127.80 129.80 33.40 57.90 0.86 141.20 691.00 4.90 3.00 1.63 1.15 0.07 0.18 10.00 31.80 138.70 139.70 94.10 146.00 1.37 228.20 1914.00 6.20 3.40 1.82 2.55 0.11 0.26 20.00 53.10 139.70 140.70 92.50 140.00 1.67 178.20 1885.00 5.60 3.30 1.75 2.35 0.10 0.21 18.00 55.20 141.98 142.98 135.00 163.00 1.61 137.80 713.00 6.20 3.90 1.54 1.23 0.09 0.22 12.00 51.50 146.20 147.20 89.90 107.00 3.64 151.40 996.00 5.20 3.20 1.57 1.92 0.11 0.24 85.00 51.80 147.20 148.20 149.00 177.00 4.61 121.40 447.00 6.80 4.40 1.50 2.25 0.11 0.30 90.00 68.60 153.04 154.04 59.70 84.80 1.77 159.20 1213.00 4.10 2.60 1.57 0.79 0.08 0.20 58.00 34.60 158.93 159.93 95.50 138.00 1.50 216.80 1648.00 6.00 4.00 1.50 2.04 0.14 0.31 59.00 48.60 162.00 163.00 153.00 211.00 1.68 91.40 203.00 7.60 5.40 1.40 2.39 0.10 0.44 36.00 53.50 163.00 164.00 59.90 80.80 1.10 150.60 252.00 21.00 5.00 4.20 2.19 0.25 0.65 64.00 35.80 volc. 171.10 172.10 57.10 86.20 0.84 135.60 208.00 19.70 4.40 4.47 3.25 0.21 0.52 38.00 18.70 181.10 182.10 27.90 36.00 0.70 124.80 170.00 18.10 3.70 4.90 1.92 0.20 0.42 38.00 13.00 184.33 185.33 49.30 96.60 1.15 113.40 296.00 11.30 4.00 2.82 4.51 0.15 0.72 62.00 23.10 185.33 186.33 88.10 139.00 1.74 113.00 256.00 9.90 6.30 1.57 0.86 0.20 0.58 38.00 46.00 a 186.33 187.33 63.50 78.70 0.90 141.60 141.00 17.80 7.30 2.43 3.32 0.19 0.60 40.00 25.50 187.33 188.33 40.20 51.30 0.93 150.60 261.00 8.90 3.70 2.41 0.51 0.35 0.41 43.00 22.30 188.33 189.33 55.10 67.30 0.80 121.40 187.00 13.60 4.40 3.09 0.57 0.26 0.42 43.00 18.10 189.33 190.33 106.00 223.00 2.20 89.20 261.00 9.20 5.50 1.67 1.62 0.17 0.39 34.00 35.90 190.33 191.33 275.00 302.00 3.23 88.80 237.00 6.80 6.30 1.08 0.54 0.18 0.50 36.00 21.20 191.33 192.33 565.00 566.00 5.29 77.40 246.00 4.90 7.70 0.63 0.32 0.14 0.25 14.00 19.80 192.33 193.33 686.00 760.00 5.88 82.40 272.00 2.80 10.10 0.27 0.24 0.17 0.27 5.00 17.70 193.33 194.33 580.00 704.00 6.14 78.20 268.00 2.50 8.10 0.31 0.32 0.15 0.28 11.00 21.00 194.33 195.33 450.00 568.00 4.23 45.40 156.00 2.80 7.00 0.40 0.65 0.09 0.57 24.00 17.80 195.33 196.33 492.00 583.00 3.70 48.80 135.00 3.30 6.60 0.50 0.62 0.09 0.59 26.00 24.00 196.33 197.33 351.00 520.00 6.00 50.20 277.00 2.80 6.00 0.46 0.30 0.09 0.31 14.00 28.70 197.33 198.33 357.00 425.00 8.05 55.80 317.00 30.00 6.80 0.44 0.31 0.11 0.33 33.00 16.60 198.33 199.33 349.00 509.00 6.49 50.60 305.00 2.30 6.50 0.35 3.45 0.10 0.35 28.00 32.90 199.33 200.33 357.00 529.00 5.12 42.60 222.00 2.50 10.90 0.29 2.95 0.09 0.33 87.00 39.90 200.33 201.33 826.00 843.00 5.56 103.20 365.00 3.20 10.30 0.31 0.36 0.22 0.59 67.00 38.90 201.33 202.33 851.00 945.00 5.29 106.20 412.00 3.30 10.00 0.33 0.26 0.24 0.35 43.00 45.70 202.33 203.33 615.00 983.00 7.33 108.20 436.00 2.90 9.60 0.30 0.27 0.23 0.32 30.00 65.70 203.33 204.33 903.00 1056.00 5.96 107.80 379.00 2.40 11.90 0.20 0.24 0.24 0.36 26.00 79.90 204.33 205.33 532.00 745.00 7.82 85.80 552.00 1.90 8.20 0.23 0.47 0.19 0.34 23.00 55.20 205.33 206.33 936.00 1042.00 6.23 119.80 493.00 2.50 13.10 0.19 0.58 0.28 0.43 28.00 80.20 206.33 207.33 713.00 969.00 5.79 99.60 583.00 3.50 10.90 0.32 0.21 0.24 0.33 21.00 68.10 207.33 208.33 779.00 1046.00 5.38 108.40 542.00 2.90 12.30 0.23 0.23 0.26 0.37 27.00 76.90 208.33 209.33 760.00 1004.00 5.65 99.80 583.00 2.40 11.60 0.21 0.26 0.24 0.32 26.00 80.90 209.33 210.33 663.00 939.00 6.26 98.20 721.00 2.50 10.20 0.24 0.27 0.25 0.36 25.00 83.40 210.33 211.33 742.00 988.00 5.76 100.80 592.00 2.30 11.70 0.19 0.50 0.33 0.27 23.00 126.00 211.33 212.23 747.00 913.00 6.08 90.40 501.00 2.10 12.20 0.17 2.27 0.32 0.29 28.00 148.00 212.23 213.13 700.00 1185.00 6.71 120.60 336.00 2.80 11.20 0.25 0.57 0.43 0.31 30.00 161.00 215.00 216.00 791.00 1429.00 7.57 128.80 306.00 4.00 13.10 0.30 0.25 0.65 0.19 15.00 203.00 216.00 217.00 658.00 1245.00 7.94 120.60 321.00 2.50 11.60 0.21 0.29 0.64 0.20 17.00 201.00 supplementary table contents of indicative chemical elements in the belanovica basin lake deposits in ppm or in %, (as indicated), including detection limit(s). lithofacies are marked as in the text (a, b and c). shaded area considers volcaniclastic rocks. g eologia c roatica marić et al.: history of the belanovica (serbia) neogene lake basin inferred from petrological and geochemical data 17 cr (ppm) ni (ppm) mg (%) ba (ppm) sr (ppm) th (ppm) sc (ppm) th/sc u (ppm) na (%) k (%) b (ppm) li (ppm) limit(s) 1ppm 1% 1ppm 1% 0.01%15% 5ppm 1% 0.5ppm0.1% 0.1ppm1000 0.5ppm 1% 0.05ppm1% 0.01%15% 0.01%15% 10ppm-1% 1ppm 1% interval (in m): from – to 217.00 218.00 929.00 990.00 6.94 102.00 363.00 2.00 12.50 0.16 0.29 0.51 0.17 15.00 152.00 218.00 219.00 749.00 1162.00 7.54 114.20 284.00 3.20 12.20 0.26 0.32 0.59 0.21 34.00 175.00 219.00 220.00 908.00 1216.00 7.88 124.60 296.00 3.90 14.80 0.26 0.29 0.59 0.22 27.00 177.00 220.00 221.00 707.00 1051.00 7.42 121.20 426.00 2.80 12.40 0.22 0.30 0.5 0.21 26.00 143.00 221.00 222.00 731.00 985.00 7.56 117.00 263.00 2.20 11.10 0.20 0.22 0.42 0.16 27.00 131.00 222.00 223.00 597.00 923.00 7.87 117.80 283.00 2.30 10.20 0.22 0.32 0.41 0.17 28.00 130.00 232.00 233.20 766.00 1050.00 9.02 85.00 264.00 2.40 12.10 0.19 3.54 0.52 0.11 26.00 41.80 242.00 243.00 992.00 1215.00 9.74 81.20 195.00 2.60 14.60 0.18 2.05 0.55 0.10 33.00 49.50 250.50 251.50 816.00 1266.00 7.94 424.00 281.00 1.80 12.50 0.14 0.12 0.47 0.07 172.00 15.70 256.00 257.00 740.00 1128.00 9.14 109.00 281.00 2.50 12.50 0.20 0.17 0.65 0.11 117.00 35.90 267.20 268.30 934.00 1231.00 8.15 78.00 146.00 2.20 13.80 0.16 0.20 0.47 0.09 88.00 43.50 278.00 279.00 775.00 1068.00 9.18 81.60 243.00 2.30 13.20 0.17 0.16 0.64 0.11 81.00 39.50 290.20 291.20 838.00 1116.00 9.40 82.80 195.00 2.40 13.50 0.78 0.20 0.62 0.11 76.00 47.50 300.00 301.20 845.00 1200.00 7.90 75.20 279.00 1.80 12.30 0.30 0.15 0.65 0.11 62.00 26.30 309.50 310.50 406.00 652.00 9.95 53.20 184.00 3.60 12.00 0.16 0.21 0.38 0.10 79.00 81.00 322.00 323.00 786.00 1083.00 8.40 67.00 202.00 2.00 12.50 0.15 0.14 0.53 0.10 62.00 35.60 327.00 328.00 867.00 1205.00 8.20 65.40 174.00 1.90 12.60 0.15 0.15 0.48 0.09 56.00 34.40 328.00 329.00 763.00 1036.00 8.30 64.00 208.00 1.80 11.50 0.15 0.15 0.49 0.09 56.00 36.40 332.00 333.00 900.00 1135.00 9.08 60.40 249.00 2.20 14.00 0.15 0.14 0.63 0.12 71.00 46.10 va -2 c 51.00 52.00 37.00 46.40 1.23 68.40 214.00 8.30 8.1 1.02 1.54 0.02 0.41 14.00 47.40 65.15 66.10 75.80 94.40 1.20 197.80 1203.00 5.60 4.5 1.33 1.59 0.05 0.27 20.00 41.10 71.00 72.00 82.70 112.00 1.17 272.20 1787.00 4.90 3.6 1.36 2.96 0.08 0.24 20.00 50.10 76.15 76.80 415.00 306.00 3.12 66.20 416.00 7.80 6.8 1.14 0.97 0.06 0.31 14.00 86.30 77.50 78.50 118.00 129.00 1.74 225.20 852.00 6.80 5.2 1.30 1.46 0.07 0.30 15.00 45.40 84.50 85.50 435.00 337.00 3.32 75.20 607.00 6.80 6.3 0.09 2.23 0.07 0.21 15.00 72.80 95.00 96.00 766.00 533.00 4.95 34.60 335.00 4.80 8.9 0.53 0.99 0.10 0.16 16.00 81.30 102.00 103.00 920.00 667.00 6.08 47.60 405.00 5.60 10 0.56 1.06 0.15 0.22 23.00 86.30 108.50 109.50 746.00 510.00 4.84 80.00 330.00 4.50 8.5 0.52 0.79 0.12 0.20 22.00 64.00 112.00 113.00 602.00 460.00 4.47 114.80 456.00 5.60 8.3 0.67 1.35 0.14 0.25 24.00 66.50 117.00 118.00 454.00 361.00 3.43 133.60 917.00 4.40 6.7 0.65 1.26 0.13 0.25 41.00 64.40 b 120.10 121.27 822.00 633.00 6.07 49.80 353.00 6.30 11 0.57 0.87 0.2 0.30 37.00 112.00 128.00 129.00 367.00 321.00 3.59 82.80 358.00 9.40 8.2 1.14 1.95 0.17 0.42 31.00 73.50 130.60 131.50 507.00 445.00 3.49 328.20 267.00 9.00 9.7 0.92 2.82 0.20 0.71 56.00 78.70 136.90 137.90 537.00 446.00 5.24 120.00 361.00 9.80 10.10 0.97 3.40 0.22 0.74 70.00 90.00 146.00 147.00 121.00 149.00 8.43 248.40 800.00 4.80 5.30 0.91 7.19 0.18 0.40 36.00 39.40 149.50 150.50 33.60 46.10 1.09 54.20 218.00 3.80 2.80 1.35 0.81 0.35 0.13 15.00 76.70 150.50 151.50 42.50 52.70 0.98 122.80 208.00 3.80 2.80 1.34 1.16 0.27 0.15 14.00 67.50 151.50 152.50 21.60 26.40 0.78 94.20 175.00 3.00 2.30 1.30 1.74 0.38 0.13 15.00 84.20 152.50 153.10 35.40 49.20 1.31 445.00 516.00 5.60 3.00 1.86 12.1 0.34 0.16 22.00 103.00 158.30 159.10 179.00 178.00 7.36 315.20 850.00 8.70 6.40 1.36 6.31 0.22 0.68 50.00 53.00 162.00 163.00 315.00 274.00 5.36 246.80 588.00 12.20 8.90 1.37 3.33 0.21 1.30 75.00 73.60 163.90 164.60 199.00 209.00 7.64 226.00 781.00 6.20 5.80 1.06 13.3 0.20 0.37 39.00 63.20 168.75 169.65 109.00 131.00 7.09 141.80 868.00 5.10 4.00 1.27 5.43 0.17 0.39 44.00 48.30 178.50 179.70 217.00 221.00 5.09 91.80 1111.00 8.60 6.20 1.38 8.16 0.25 1.06 100.00 93.80 182.70 183.70 129.00 142.00 4.71 62.20 1760.00 7.10 5.00 1.42 2.94 0.22 0.67 57.00 61.70 191.00 192.00 303.00 269.00 2.51 173.00 641.00 16.70 10.00 1.67 3.52 0.34 0.53 32.00 57.50 193.20 194.20 527.00 405.00 3.52 52.60 419.00 9.40 9.60 0.18 1.86 0.23 0.35 21.00 79.10 195.00 196.00 600.00 482.00 4.13 58.00 317.00 10.90 11.40 0.95 7.42 0.27 0.42 25.00 85.80 201.70 202.50 296.00 241.00 8.29 2891.40 1564.00 5.80 6.20 0.93 4.54 0.22 0.37 31.00 60.50 202.50 204.00 649.00 502.00 5.68 26.20 576.00 6.00 10.50 0.57 1.64 0.29 0.40 29.00 114.00 209.50 210.50 369.00 295.00 2.71 36.60 384.00 7.40 8.20 0.90 1.11 0.24 0.43 26.00 65.70 214.10 215.10 333.00 271.00 6.39 352.80 1214.00 6.40 6.60 1.03 7.48 0.33 0.50 57.00 142.00 218.30 219.40 418.00 325.00 4.92 62.60 717.00 8.00 8.20 0.97 4.81 0.28 0.66 60.00 100.00 221.50 222.40 70.70 88.70 3.07 64.60 917.00 6.90 4.30 1.60 10.5 0.22 0.84 73.00 84.80 222.40 223.30 82.90 83.20 5.74 147.40 1820.00 5.90 3.50 1.68 19.8 0.43 0.66 64.00 96.30 223.30 224.20 67.50 70.70 3.26 873.00 1888.00 7.40 3.00 2.40 39.6 0.43 0.46 51.00 85.10 224.20 225.10 69.10 102.00 2.14 92.80 1240.00 7.70 4.20 2.46 22.4 0.23 0.74 56.00 64.70 229.05 230.20 16.70 18.60 1.67 227.40 283.00 8.90 3.40 1.83 3.25 0.57 0.47 31.00 127.00 230.20 231.00 11.20 8.80 1.13 321.00 149.00 5.10 3.10 2.69 2.03 0.56 0.47 18.00 75.10 g eo lo gi a c ro at ic a geologia croatica 72/118 cr (ppm) ni (ppm) mg (%) ba (ppm) sr (ppm) th (ppm) sc (ppm) th/sc u (ppm) na (%) k (%) b (ppm) li (ppm) limit(s) 1ppm 1% 1ppm 1% 0.01%15% 5ppm 1% 0.5ppm0.1% 0.1ppm1000 0.5ppm 1% 0.05ppm1% 0.01%15% 0.01%15% 10ppm-1% 1ppm 1% interval (in m): from – to 231.00 231.80 8.50 5.60 1.48 360.20 274.00 8.80 3.20 1.64 3.02 0.64 0.49 24.00 108.00 231.80 232.45 13.80 15.40 2.30 453.60 592.00 14.70 5.00 2.75 6.21 0.73 0.49 30.00 152.00 240.00 241.00 213.00 199.00 2.01 42.40 292.00 11.50 6.40 2.67 2.24 0.19 0.58 45.00 54.90 247.30 248.50 357.00 294.00 2.42 37.00 303.00 11.00 9.50 1.79 1.61 0.26 0.44 29.00 60.70 252.00 253.20 111.00 128.00 1.40 48.80 299.00 12.70 5.80 2.19 2.55 0.26 0.55 36.00 34.60 a 258.20 259.20 79.10 117.00 1.13 63.20 270.00 16.00 6.00 2.66 7.14 0.28 0.63 47.00 30.90 259.20 260.20 64.80 105.00 1.10 52.80 185.00 14.00 6.10 2.29 1.36 0.27 0.62 34.00 31.40 270.50 271.50 247.00 79.00 0.98 178.60 267.00 17.80 14.00 1.27 4.54 0.40 0.45 43.00 19.80 273.50 274.50 75.30 34.50 0.97 114.80 206.00 24.30 8.90 2.73 5.13 0.33 0.61 37.00 17.20 277.60 278.60 10.60 5.20 0.54 82.20 65.50 29.80 7.50 4.01 3.24 0.17 0.44 14.00 6.60 287.00 288.00 9.80 4.40 0.58 115.20 58.00 28.90 7.20 4.19 2.75 0.18 0.48 5.00 13.10 293.00 294.00 9.40 4.40 0.55 100.20 56.00 28.50 6.80 0.95 3.99 0.21 0.55 5.00 13.50 va -3 c 84.50 85.50 32.40 43.90 0.93 96.40 140.00 6.80 7.1 1.04 3.21 0.02 0.34 18.00 36.30 87.50 88.50 19.00 21.80 0.47 80.00 101.00 4.70 3.5 0.95 1.06 0.03 0.16 12.00 18.50 89.50 90.50 51.60 79.10 1.14 119.20 297.00 9.50 8.2 1.34 1.73 0.03 0.36 18.00 47.80 93.20 94.20 39.20 50.00 1.12 92.60 174.00 8.80 8.4 1.15 1.54 0.02 0.4 14.00 55.30 96.20 97.20 36.20 49.30 1.04 86.80 196.00 9.10 7.9 1.04 1.81 0.02 0.35 12.00 48.10 105.20 106.20 32.90 47.40 1.10 81.60 167.00 8.20 7.3 1.15 1.46 0.02 0.34 10.00 48.00 109.70 110.70 23.80 32.90 0.76 120.00 134.00 6.00 5.4 1.12 1.12 0.03 0.27 5.00 33.00 118.70 119.70 15.30 24.80 0.32 30.00 35.50 2.50 1.50 1.11 1.84 0.02 0.10 18.00 8.00 b 128.20 129.20 22.00 32.40 0.66 68.80 93.80 5.70 4.40 1.29 0.90 0.02 0.22 18.00 21.10 136.70 137.70 24.90 37.90 0.82 64.40 108.00 6.30 5.30 1.18 1.12 0.02 0.27 18.00 29.30 154.70 155.70 35.40 54.20 1.00 62.80 133.00 6.90 6.50 1.06 0.98 0.02 0.35 15.00 43.00 161.20 162.20 18.60 25.10 0.38 39.80 86.40 4.00 2.50 1.60 0.83 0.03 0.13 14.00 12.50 168.20 169.20 39.10 77.50 1.16 72.00 298.00 9.60 8.70 1.10 1.67 0.03 0.39 42.00 48.60 173.20 174.20 68.80 126.00 1.39 192.40 601.00 5.70 5.10 1.11 1.90 0.04 0.25 33.00 37.30 180.50 181.50 49.50 90.00 0.94 246.60 1716.00 4.40 3.70 1.19 2.44 0.06 0.22 32.00 27.60 186.78 187.28 28.10 51.60 0.71 594.00 333.00 13.70 3.00 4.53 4.53 0.03 0.23 16.00 40.00 190.70 191.70 52.50 97.20 1.25 123.00 901.00 6.40 4.50 1.42 1.86 0.07 0.26 20.00 39.50 194.00 195.00 47.20 84.80 1.04 76.00 444.00 7.30 5.50 1.32 2.08 0.08 0.28 21.00 31.20 199.30 200.30 71.70 120.00 1.49 117.00 958.00 4.80 3.80 1.26 1.39 0.06 0.21 17.00 35.90 202.70 203.70 53.10 79.90 1.28 72.40 295.00 7.50 5.40 1.38 2.47 0.07 0.42 18.00 56.60 209.50 210.50 107.00 131.00 1.54 192.20 1569.00 5.60 4.10 1.36 2.04 0.09 0.23 26.00 51.60 219.00 220.00 101.00 146.00 1.48 125.40 1010.00 4.50 3.80 1.18 1.59 0.08 0.19 23.00 38.10 225.90 226.90 156.00 197.00 2.16 110.00 869.00 5.10 4.60 1.10 1.42 0.10 0.21 20.00 46.60 229.40 230.40 160.00 220.00 2.03 56.00 331.00 8.40 5.90 1.42 1.43 0.11 0.34 21.00 57.40 a 231.30 232.30 218.00 215.00 3.67 69.00 605.00 6.70 6.20 1.08 1.50 0.11 0.33 25.00 66.30 257.30 258.30 400.00 338.00 3.68 40.60 314.00 10.30 9.70 1.06 1.27 0.16 0.46 23.00 66.90 272.00 273.00 428.00 391.00 2.95 103.80 260.00 9.90 11.70 0.84 0.97 0.18 0.42 20.00 78.10 84.50 85.50 32.40 43.90 0.93 96.40 140.00 6.80 7.10 0.95 3.21 0.02 0.34 18.00 36.30 87.50 88.50 19.00 21.80 0.47 80.00 101.00 4.70 3.50 1.34 1.06 0.03 0.16 12.00 18.50 89.50 90.50 51.60 79.10 1.14 119.20 297.00 9.50 8.20 1.16 1.73 0.03 0.36 18.00 47.80 2018 | 71/2 | 91–95 | 6 figs. | 1 tab. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction in south korea, some community water-supply systems with high levels of uranium-238 and radon-222 in drinking groundwater naturally occurring radioactive materials (norm) in the groundwater of two islands with various geologic settings in south korea moonsu kim, ikhyun kim, hyunkoo kim, hunje jo, sunhwa park, jongyeon hwang, dongsoo kim, seongjin jo, taeseung kim and hyenmi cheong soil and groundwater division, national institute of environmental research, incheon, south korea; (hyd009@korea.kr) doi: 10.4154/gc.2018.11 abstract since 2007, naturally occurring radioactive materials (norm) such as uranium-238 and radon-222 etc. in groundwater from the community water-supply systems (cws) in two islands have been studied in south korea. in 71 samples from ganghwa (g) island, the maximum value of uranium-238 concentration is 72.21 μg/l. 3 cwss (4.2%) exceeded the maximum contaminant level (mcl) of 30 μg/l for uranium-238. the maximum value of radon-222 activity is 614 bq/l. 28 cwss (39.4 %) did not meet the united states environment protection agency (us epa) proposed alternative maximum contaminant level (amcl) of 148 bq/l for radon-222. at all cws that did not meet the us epa’s mcl or amcl, some appropriate actions were taken such as water treatment, alternative well development, mixing water of different origins, and so forth. in the 52 cwss of jeju (j) island, the maximum value of uranium-238 and radon-222 concentrations are 1.37 μg/l and 94.83 bq/l, respectively. all values for uranium-238, gross alpha, and radon-222 meet mcl and proposed amcl of us epa drinking water standard. the two islands have different geological settings that are believed to be the causes of the big differences in the norm levels. geologically an old island has much higher norm values than a young island formed in the quaternary period due to hydrogeological factors such as recharge and infiltration rates of precipitation. the residence times in the aquifers for water-rock (mineral) interactions are very different from each other. have been reported and broadcast several times by major media such as news 9 by the korean broadcasting system (kbs) and newsdesk by munhwa broadcasting corporation (mbc) article history: manuscript received december 11, 2017 revised manuscript accepted june 18, 2018 available online june 21, 2018 keywords: geologic setting, groundwater, uranium-238, radon-222 figure 1. locations of studied two islands and their geologic maps with cwss (colour marks). g eo lo gi a c ro at ic a geologia croatica 71/292 television news etc., and the various newspapers such as the hankyoreh and the chosunilbo etc., since 1998. the news made the national assembly of the republic of korea, requiring several actions by ministry of environment during the inspection and investigation of state administration. studies and investigations, therefore, on naturally occurring radioactive materials (norm) in groundwater have been performed since 1999. uranium-238 is known as the chemical that is increasing kidney toxicity (us epa, 2000) and radon-222 is infamous as the norm chemical causing lung cancer (national academy press, 1999). this study aims to determine the levels of the norm in groundwater from the community water-supply systems (cwss) on two islands in south korea (fig. 1). areas, population, and annual precipitations of two islands are 410.6 km2, 68,010 people, and 1,076 mm/year in 2016 for ganghwa (g) island and 1848.7 km2, 641,597 people, and 1,416 mm/year in 2016 for jeju (j) island (korea land & housing corporation, 2017). the studied islands have different geological settings investigated and mapped by the korea institute of geoscience and mineral resources (kigam). the g island is composed of precambrian metamorphic rocks, jurassic daebo granite, cretaceous bulguksa granitoids, cretaceous acidic dykes and quaternary deposits. the metamorphic rocks of g island consist of quartz, k-feldspar, plagioclase, biotite, muscovite and hornblende with rare garnet. the granitoids consist of quartz, plagioclase, kfeldspar, biotite, hornblende and zircon, two-mica granite. the acidic dykes are classified into felsite dyke, rhyolite dyke, pegmatite vein and quartz vein (hwang & kihm, 2005). the j island is a shield volcano, composed mainly of basaltic lava flows and subordinate amounts of pyroclastic and sedimentary rocks. the lavas of the jeju island are known as basalt, trachybasalt, basaltic trachyandesit, trachyandesite and trachyte formed in prepliocene (cretaceous) volcanic and plutonic rocks. volcanic rocks of j island are composed of olivine, plagioclase, and pyroxene (park et al., 2000). the norm concentrations in the aquifers of the two islands with various geological settings are evaluated. 2. materials and methods in order to define the levels of norm for uranium-238 and radon-222 in groundwater from g island located in the north-western side and from j island located in the southern part of south korea, a total of 123 cwss using groundwater as a drinking water resource had been investigated for 10 years from 2007 to 2016 (nier-2007, -2008, -2009, -2010, -2011, -2012, -2013, -2014, -2015, -2016). groundwater samples for uranium-238 were filtered by 0.45 μm membrane (advantec®) in the field and transported to the laboratory and then analysed by inductively coupled plasma mass spectrometer (icp-ms, agilent 7500 series and perkinelmer nexiontm 350d) in the national institute of environmental research (nier). the range of uranium-238 detection limits (dl) measured every year for the quality assurance and quality control (qa/qc) was from 0.01 to 0.09 μg/l. the range of accuracies and precisions for the qa/qc were 88.85% to 99.67% and 0.63% to 4.92%, respectively. samples for radon-222 were prepared in the field. 8 ml of the groundwater was injected into a 20 ml high density polyethylene vial (hdpe) to which 12 ml of scintillation cocktail (optiphase hisafe3) had been added. the vial was shaken for about 5 minutes to mix the sample with the cocktail. the sample was then equilibrated for 3 hours and then counted for 60 minutes in the liquid scintillation counter (lsc, perkinelmer quantulus 1220) using energy discrimination for alpha particles in nier (hahn & pia, 1991). one litre of groundwater was sampled and tested for gross alpha, with 15 ml of 1n hno3 added to the samples on-site prior to transfer to the laboratory. the appropriate amount of sample was collected for analysis. collected samples were evaporated, concentrated and dried to produce solid samples. the solid samples were analyzed by gas-flow proportional counter (gpc, canberra tennelec™ series 5) in nier (us epa, 1980). the range of minimum detectable activities (mda) calculated every year for the qa/qc is from 0.02 to 0.04 bq/l. 3. results in 71 groundwater samples from g island, the maximum and minimum values of uranium-238 concentrations were 72.21 μg/l and nd (not detected; below the detection limit), respectively. the average and median values of uranium-238 in the samples were 5.56 μg/l and 1.32 μg/l, respectively. 3 cwss (4.2%) exceeded the maximum concentration level (mcl) of 30 μg/l for uranium-238, which is regulated by the national primary drinking water standard of the united states environmental protection agency (us epa). the maximum and minimum values of radon-222 activity were 614 bq/l and 6 bq/l, respectively. the average and median values of radon-222 in the groundwater were 133 bq/l and 111 bq/l, respectively. in 28 cwss radon-222 activity concentrations exceeded the amcl value of 148 bq/l. the maximum and minimum values of gross alpha activities were 0.51 bq/l and nd (not detected; below the minimum detectable activity), respectively. the average and median values of gross alpha in groundwater were 0.07 bq/l and 0.04 bq/l, respectively. all gross alpha values meet the maximum concentration level (mcl) of 0.55 bq/l, regulated by the us epa‘s national primary drinking water standard. all cws that did not meet the us epa’s mcl or amcl have taken appropriate action, such as water treatment, alternative well development, mixing water of different origins, and so forth. in the 52 cwss of j island, the maximum and minimum values of uranium-238 concentrations were 1.37 μg/l and nd (not detected), respectively. the average and median values of urani um-238 in the groundwater were 0.15 μg/l and 0.07 μg/l, respectively. the maximum and minimum values of radon-222 activities were 94.83 bq/l and 0.07 bq/l, respectively. the average and median values of radon-222 in the groundwater were 23.74 bq/l and 18.32 bq/l, respectively. the maximum and minimum values of gross alpha activities were 0.24 bq/l and nd, respectively. the average and median values of gross alpha in the groundwater were 0.03 bq/l and 0.00 bq/l, respectively. all values for uranium-238 and gross alpha meet the maximum concentration levels (mcl) regulated by the us epa drinking water standard of 30 μg/l and 0.55 bq/l, respectively. none of the radon-222 concentration values exceeded the us epa proposed alternative maximum concentration level (amcl) of 148 bq/l (fig. 2). figure 3 shows the box plots of uranium-238, radon-222, and gross alpha values of groundwater samples from the two islands. table 1 (nier-2007, -2008, -2009, -2010, -2011, -2012, -2013, -2014, -2015, -2016) shows the uranium-238, radon-222, and gross alpha concentrations of minimum, maximum, average and median values. in addition, this table includes the basic statistical values of well depths. however, we could not acquire the data of all screen depths and some of the well depths of two islands. the number of well depth values is 48 from the g island. the number of well depths is 45 from the j island. the ranges of g eologia c roatica kim et al.: naturally occurring radioactive materials (norm) in the groundwater of two islands with various geologic settings in south korea 93 well depths in the j island is much wider than those in the g island. it depends on the different geological settings of the two islands. 4. discussion the two islands have different geological settings that may explain the causes of the big differences observed in the norm levels. most of the g island is composed of precambrian metamorphic rocks, jurassic granite, cretaceous granitoids, cretaceous acidic dykes and quaternary deposits (hwang & kihm, 2005). j island is a shield volcano, consisting mainly of basaltic lava flows and subordinate amount of pyroclastic and sedimentary rocks formed in pleistocene epoch, quaternary period, cenozoic era (park et al., 1998). uranium, one of the immiscible elements, increases its content as the fractional crystallization process in which crystalline rock is produced. thus, mafic rocks containing basalts contain little uranium (greeman, 1991). the common ranges of uranium contents are 2.20 ~ 15.00ppm in granite, 0.10 ~ 10.00ppm in gneiss and 0.10 ~ 2.30ppm in basalt (dahlkamp, 2013). the rocks mainly composed of g island are granitoids and metamorphic rocks, and the rocks composed of j island are volcanic rocks. porosity of crystalline rocks including granite and metamorphic rocks is < 0.001 to 0.01. porosity of basalt is < 0.01 to 0.10 (intera environmental consultants, inc., 1983). due to different types of rocks, there is a large difference in transmissivity. the average transmissivity values of groundwaters measured in g island and j island are 5 m2/d and 560 m2/d, respectively (han river flood control office et al., 2012). the recharge and infiltration rate of precipitation in j island is much higher than that of g island, and the span of water cycle from recharge into aquifers to discharge from the aquifers in j island is much shorter than that in g island. the average electrical conductivity of the national groundwater network in g island is 449.49 μs/cm and that in j island is 126.51 μs/cm (national groundwater information center). the electrical conductivity table 1. statistics of well depth, uranium-238, radon-222, and gross alpha values. site basic statistics well depth (m) rn-222 (bq/l) uranium-238 (μg/l) gross-α (bq/l) g island (n=71) min. 70 6.2±0.3 nd* nd** max 250 615±3 72.21 0.51 avg. 98 132.78 5.49 0.07 median 100 111.01 1.16 0.04 j island (n=52) min. 43 0.07±0.02 nd* nd** max 450 94.8±1.5 1.37 0.24±0.16 avg. 182 23.74 0.15 0.03 median 143 18.32 0.07 0.00*** * nd of uranium-238 : below the detection limits (dl, 0.01 ~ 0.09 μg/l) ** nd of gross-α: below minimum detectable activities (mda, 0.02 ~ 0.04 bq/l) *** all values that were below the mda assign the 0 figure 2. bar charts of uranium-238, radon-222, and gross alpha values of cwss in two islands. figure 3. box plots of uranium-238, radon-222, and gross alpha values of cwss in two islands. g eo lo gi a c ro at ic a geologia croatica 71/294 can be converted to total dissolved solids (tds). the higher the tds value, the longer the residence time is expected because high tds values are the result of long-term water-rock reactions (nelson, 2002). the difference of electric conductivities indicates that the groundwater in the aquifers of g island with a long residence time has much higher the norm levels than that of j island with its relatively short residence time. this indicates that groundwater in metamorphic and granitic rocks with relatively longer waterrock interaction times has a much higher level of uranium, radon, and gross alpha values than basaltic rocks with relatively short water-mineral interaction times. correlation coefficient and p value between uranium-238 and radon-222 concentrations were 0.22 and 0.058 in the g island, respectively. there is little correlation between uranium-238 and radon-222 concentrations in groundwater in the g island. this relationship may be attributed to their unique physico-chemical characteristics such as half-lives (238u: 4.5 billion years, 222rn: 3.82 days), phases (238u: dissolved ions, 222rn: inert gas), etc. groundwaters discharged from precambrian biotite gneiss, jurassic biotite granite areas and jurassic two-mica granite areas contain relatively high values of uranium-238 concentrations (>30 μg/l). groundwaters bearing relatively high levels of radon-222 activity (>148 bq/l) are dominantly found in the regions of precambrian granitic gneiss. groundwaters discharged from nine geologic settings that are jurassic biotite granite, precambrian biotite gneiss, precambrian quartz schist, precambrian mica schist, precambrian biotite schist, unknown granite, jurassic granite, jurassic two-mica granite, jurassic porphyritic biotite granite areas have also relatively high levels of radon-222 activities (>148 bq/l) (fig. 4). no values of gross alpha exceed the mcl of us epa. 2 and 8 cwss (64.3 %) exceeded us epa mcl/amcl values of uranium-238/radon-222 among 14 cwss in granitic figure 4. bubble plot of uranium and radon concentrations in the g island. figure 5. uranium-238 and radon-222 values based on geological settings in the g island. g eologia c roatica kim et al.: naturally occurring radioactive materials (norm) in the groundwater of two islands with various geologic settings in south korea 95 rock areas, respectively. 1 and 16 cwss (39.0 %) exceeded us epa mcl/amcl values of uranium-238/radon-222 among 41 cwss in gneiss rock areas, respectively. 4 cwss (23.5 %) exceeded us epa amcl proposed value of radon-222 among 17 cwss in schist rock areas (fig. 5). in the j island, uranium-238 and gross alpha values in groundwater are very low, however, radon-222 values show their existence in the groundwater system. this implies that a shield volcano island formed in the quaternary period has little norm in their aquifers (fig. 6). the highest concentrations of radon-222 (94 bq/l) and uranium-238 (1.37 μg/l) in groundwater are found in q3 consisting of trachy-basalt and trachy-andesite. 5. conclusion norm in groundwater from the two islands with different geological settings in south korea had been studied from 2007 to 2016. jeju island has low norm values under the mcl and amcl values of uranium-238, gross alpha, and radon-222. however, ganghwa island has relatively high values of norm with 3.2 % and 39.4 % of uranium-238 mcl and radon-222 amcl exceeding ratios, respectively. the result indicates that the geology of aquifers is the major factor of the norm contents of groundwater. acknowledgement this work was supported by a grant from the national institute of environment research (nier), funded by the ministry of environment (moe) of the republic of korea (nier-rp2016-324). references dahlkamp, f.j. (1993): uranium ore deposits.– springer science & business media, 25–30. doi: 10.1007/978-3-662-02892-6 greeman, d.j. (1992): the geochemistry of uranium, thorium, and radium in soils of the eastern united states.– pennsylvania state univ., mont alto, pa (united states), 225 p. hahn, p.b. & pia, s.h. (1991): determination of radon in drinking water by liquid scintillation counting. method 913.– us epa. han river flood control office & korea water resources corporation (2012): 2011 national watershed survey statistics and analysis report, 65 p. hwang, j.h. & kihm, y.h. (2005): geologic report of the ganghwa·onsuri sheet.– korea institute of geoscience and mineral resources, 1–46. intera environmental consultants, inc. (1983): porosity, permeability, and their relationship in granite, basalt, and tuff, accession de83-011519, ntis, springfield, virginia 22161. korea land & housing corporation (2017): statistics of urban plan, 51–80. national academy press (1999): risk assessment of radon in drinking water.– http://www.nap.edu/catalog/6287.html national groundwater information center: groundwater observation network.-current status and observation graph of observation network. [online: http://www.gims.go.kr/natnobsvstts.do] national institute of environmental reasearch (2007): an investigation of natural radionuclide levels in groundwater (nier no. 2007-87-943) national institute of environmental reasearch (2008): an investigation of natural radionuclide levels in groundwater(ⅱ) (nier no. 2008-67-1017) national institute of environmental reasearch (2009): an investigation of natural radionuclide levels in groundwater(ⅲ) (nier no. 2009-61-1117) national institute of environmental reasearch (2010): an investigation on natural radioactivity levels in groundwater(‘10) (nier no. 2010-471222) national institute of environmental reasearch (2011): study on naturally occurring radioactive materials (n.o.r.m) in groundwater in south korea (‘11) (nier-rp2011-1401) national institute of environmental reasearch (2012): study on naturally occurring radioactive materials (n.o.r.m) in groundwater in south korea (‘12) (nier-rp2012-196) national institute of environmental reasearch (2013): study on naturally occurring radioactive materials (n.o.r.m) in groundwater in south korea (‘13) (nier-rp2013-384) national institute of environmental reasearch (2014): study on naturally occurring radioactive materials (n.o.r.m) in groundwater in south korea (‘14) (nier-rp2014-383) national institute of environmental reasearch (2015): study on naturally occurring radioactive materials (n.o.r.m) in groundwater in south korea (‘15) (nier-rp2015-388) national institute of environmental reasearch (2016): study on naturally occurring radioactive materials (n.o.r.m) in groundwater in south korea (‘16) (nier-rp2016-324) nelson, d. (2002): natural variations in the composition of groundwater. drinking water program. oregon department of human services, springfield, oregon, 3. park, k.h., lee, b.j., kim, j.c., cho, d.l., lee, s.r., choi, h.i., park, d.w., lee, s.l., choi, y.s., yang, d.y., kim, j.y., seo, j.y. & shin, h.m. (2000): explanatory note of the jeju (baekado, jinnampo) sheet – korea institute of geoscience and mineral resources, 5–60. park, k.h., song, k.y., hwang, j.h., lee, b.j., cho, d.l., kim, j.c., cho, b.w., kim, y.b., choi, p.y., lee, s.r. & choi, h.i. (1998): geologic report of the cheju-aewol sheet – korea institute of geoscience and mineral resources, 1–290. us epa (1980): epa method 900.0. gross alpha and gross beta radioactivity in drinking water in ‘‘prescribed procedures for measurement of radioactivity in drinking water’’, epa–600/4–80–032. us epa (2000): national primary drinking water regulations; radionuclides; final rule, 40 cfr parts 9, 141, and 142. – federal register / vol. 65, no. 236, 76708–76753. figure 6. bubble plot of uranium-238 and radon-222 concentrations in the j island. g eo lo gi a c ro at ic a geologia croatica 71/296 2023 | 76/3 | 147–156 | 5 figs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the lower cretaceous sedimentary successions in the area around belgrade are crucial to understanding the late mesozoic geodynamic history of the dinarides, because of their position in the proximity of the plate boundary between the adriatic (dinarides) and the moesian plates (fig. 1a, b). the complex geological setting of the study area is interpreted as a mosaic of continental units (adriatic or european affinity; schmid et al., 2008, 2020 and references therein), which are separated by the so-called sava suture zone (schmid et al., 2020 and references therein), and remnants of domains with oceanic lithosphere (west vardar and east vardar ophiolites (sensu schmid et al., 2008, 2020; fig. 1a; neo-tethys ophiolites sensu gawlick et al., 2009). previously, there has been no consensus as to which tectonic unit the lower cretaceous sedimentary rocks (paraflysch sequence sensu dimitrijević & dimitrijević (1976) belong: the main vardar zone (mvb/z; karamata, 2006; fig. 1b), the sava zone (schmid et al., 2008; fig. 1b), or the inner dinarides (kopaonik ridge and block unit =kbr/u =; fig. 1c), or to a sequence with european affinity thrust over the wider adria plate (toljić et al., 2018). this controversy is an ongoing discussion (e.g., toljić et al., 2018; bragin et al., 2019; schmid et al., 2020). toljić et al. (2018) in the latest paper attributed the paraflysch sequence to be deposited on the outer passive margin of the moesian plate (carpatho-balkanides), and in the oceanic basin between the wider adria plate to the west (dinarides) and the moesian plate (europe) to the east. toljić et al. (2018) interpreted the entire cretaceous to palaeogene sedimentary evolution in the belgrade area as a fore-arc basin infill, which should have been palaeogeographically situ middle aptian orbitolinid limestones in belgrade (serbia): microfacies and depositional environment bojana đorđević 1,*, hans-jürgen gawlick2, nevenka djerić1, felix schlagintweit3 and miloš radonjić1 1 university of belgrade, faculty of mining and geology, đušina 7, beograd, serbia; (*corresponding author: bojana.dzinic@rgf.bg.ac.rs) 2 montanuniversität leoben, franz josef-straße 18, 8700 leoben, austria 3 lerchenauerstr. 167, 80935 munich, germany doi: 10.4154/gc.2023.09 abstract lower cretaceous (aptian) shallow-marine limestones with intercalated polymictic conglomerates were investigated with respect to their biostratigraphic age and their microfacies. they are the younger part of the generally carbonate-siliciclastic lower cretaceous deep-water (max. few hundred metres) turbiditic sequences (“paraflysch”) of the so-called east vardar zone in the belgrade area. the biostratigraphic age of the limestones was determined by orbitolinid foraminifera: the co-occurrence of dictyoconus? pachymarginalis schroeder and mesorbitolina texana (roemer) besides various other microfossils suggest a biostratigraphic age of this shallow-marine limestone succession as middle aptian (gargasian). radiolarite components in the conglomerates are triassic in age and were derived from the obducted middle triassic to middle jurassic neo-tethys ophiolites and/or their ophiolitic mélanges on the wider adria plate. from both the first precise biostratigraphic age dating as middle aptian combined with microfacies analysis of these shallow-marine limestones and the component spectrum in the intercalated conglomerates, it can be concluded that the lower cretaceous turbiditic “paraflysch” succession was deposited on the eastern rim of the dinarides. the results will allow a better comparison of the different lower cretaceous sedimentary successions deposited on the eastern margin of the dinarides. ated on the moesian plate margin (supragetic nappes according to schmid et al., 2008). during the assumed campanian–early palaeogene collision between moesia and the dinarides, this fore-arc basin was thrust onto the adria plate and should mark the suture zone. in the early cretaceous “paraflysch” succession, the shallow-marine early cretaceous limestones with conglomerate intercalations locally should evidence a sea-level lowstand (toljić et al., 2018). these shallow-marine limestones contain a rich orbitolinid foraminifera fauna that has not previously been studied. the exact age of these shallow-water limestones is not known, and associated rocks, i.e., intercalated conglomerates with fluvial transported components from a hinterland, are not studied and their hinterland should be according to toljić et al. (2018) the moesian plate. however, due to the occurrence of radiolarite and ophiolite components in these conglomerates associated with the shallow-marine early cretaceous orbitolinidbearing limestones, we disagree with the palaeogeographical interpretation of toljić et al. (2018). cretaceous sedimentary rocks deposited in the wider belgrade area are subdivided into the central and east belgrade facies, i.e. into different “sub-basins”. the early cretaceous “paraflysch” sensu dimitrijević (1997) is an overstep sequence above ophiolites/ophiolitic mélange, mainly preserved in the central belgrade facies. in contrast, the east belgrade facies is incompletely exposed and characterized by late lower cretaceous shallow-water limestones which pass into the urgonian-type reefal sedimentary rocks, both interpreted as deposited in a fore-arc basin on the moesian margin (toljić et al., 2018). however, in the late cretaceous, rudist-bearing shallow-marine limestones were formed throughout the adriatic plate (sladićarticle history: manuscript received march 15, 2021 revised manuscript accepted september 04, 2023 available online october 16, 2023 keywords: orbitolinidae, microfacies, early cretaceous, dinarides g eo lo gi a c ro at ic a geologia croatica 76/3148 trifunović, 1998), as well as in the wider belgrade area. they represent the beginning of a new sedimentary cycle, starting in the early late cretaceous, after the “mid-cretaceous” tectonic motions, which resulted in the eastern mediterranean area in a new plate configuration (e.g. csontos & vörös, 2004). after a long period of exposure and continental weathering of huge areas of the inner dinarides after the tithonian uplift and unroofing (gawlick et al., 2020 and references therein), including the so-called eastand west-vardar ophiolites (compare schmid et al., 2008, 2020), the whole area was flooded and a widespread shallow-water reefal evolution was established with a very limited palaeogeographic meaning. in contrast, bragin et al. (2019) used the findings of late jurassic radiolarians to suggest that the central and east belgrade facies sensu toljić et al. (2018) have an adriatic affinity. in fact, the recent controversial discussion clearly evidenced that there is figure 1. a) the tectonic setting of the adria – europe collision zone in central serbia (modified after schmid et al., 2020). b) overview of the terrains/composite units of central serbia (modified after karamata, 2006). note that the geographical position of the map is approximately similar to fig. 1a. c) geological sketch map of the central area of belgrade. the qhite circle marks the position of the studied section at the košutnjak railway station (see fig. 2). modified after marković et al., 1984. g eologia c roatica đorđević et al.: middle aptian orbitolinid limestones in belgrade (serbia): microfacies and depositional environment 149 a great need for additional data from the early cretaceous sedimentary rocks to answer the still open questions in this area. this issue is crucial geodynamic reconstruction of the cretaceous and the evolution of the vardar zone between moesia and adria and the early cretaceous evolution of the inner dinarides, a continental area with erosion during that time span. the early cretaceous erosional products of the inner dinarides are well studied in the partially underfilled foreland basins to the west (e.g. mikes et al., 2008), but practically nothing has been studied in their eastern part, i.e. the “paraflysch” sequences according to dimitrijević & dimitrijević (1976). the sedimentological evolution, i.e. biostratigraphic age dating, microfacies analysis and component analysis of the intercalated turbidites and mass transport deposits of the early cretaceous sedimentary rocks in the whole area is only roughly constrained (toljić et al., 2018 and references therein). microfacies analysis of carbonate rocks and component analysis of breccias/conglomerates/turbidites is completely missing. therefore, there is a need for detailed sedimentological studies and detailed biostratigraphic age dating for an exact correlation of the different cretaceous successions to unravel the depositional regime and palaeogeographic position of the “paraflysch” sequence. only on the basis of a precise age and a provenance analysis of the components in the early cretaceous succession can a palaeogeographic reconstruction of their depositional area be possible, i.e. the eastern dinarides, europe, or an estimated oceanic domain between adria and moesia (europe). the aim of this study is to present new biostratigraphic age and microfacies data of these early cretaceous (aptian) shallowmarine limestones and to describe some key components (radiolarites) of the associated fluviatile conglomerates. the presented data will allow a better comparison to be made with similar sedimentary sequences in the wider surroundings, which should result in a better understanding of the geology and evolution of the plate boundary between the dinarides and moesia. 2. geological setting in the belgrade area, the lower cretaceous sedimentary rocks, deposited on top of the upper jurassic ophiolitic mélange (toljić et al., 2018 and references therein; compare bragin et al., 2019) are represented by two distinct facies: 1) sedimentary rocks composed of sandstones, siltstones, marlstones, sandy limestones, and limestones; 2) shallow-water reef limestones and siliciclastics (anđelković, 1973; pavlović et al., 1979; filipović et al., 1979; marković et al., 1985) (fig. 1c). these valanginian to aptian sedimentary successions of central serbia are termed “paraf lysch” by dimitrijević & dimitrijević (1976, 1987) with respect to their sedimentological features. similar deposits of comparable age range but a different geotectonic position related to the vergence of the thrust belts are described from the alps, dinarides, albanides and hellenides (e.g., the schrambach and rossfeld formations missoni & gawlick, 2011a; krische et al., 2014; bohinj formation – kukoč et al., 2012; vranduk formation blanchet et al., 1970; mikes et al., 2008; vermoshi flysch meço & aliaj, 2000; marroni et al., 2009; firza formation – gardin et al., 1996; kurbnesh formation – schlagintweit et al., 2008; boeotian flysch – nirta et al., 2015). in contrast to the “paraflysch”, these sedimentary successions were deposited west of the obducted ophiolites in early cretaceous underfilled foreland basins. only in northern greece in a similar palaeogeographic setting to the “paraflysch” was a practically identical earliest early cretaceous (berriasian–valanginian) sedimentary succession deposited on top of obducted ophiolites/ophiolitic mélange (“east vardar ophiolites” and equivalents) (kostaki et al., 2013 and references therein). however, from all these lower cretaceous (berriasian to aptian) successions with reworked material from the wider adria plate the overlying upper barremian, aptian (and younger) shallow-water deposits with orbitolinid foraminifera are practically not described, because they are mostly eroded. exceptions are only known from the northern calcareous alps (schlagintweit et al., 2012b and references therein) or the albanides (robertson et al., 2012; schlagintweit et al., 2012a and references therein). in serbia, the occurrence of “paleodictyoconus arabicus” from the vardar zone in the kopaonik area was reported by zelić et al. (2010, fig. 5c) without sedimentological or microfacies studies. to fill this gap in knowledge the orbitolinid-bearing shallow-water limestones from the east vardar zone are described for the first time. the shallow-marine barremian–aptian limestones in the surroundings of belgrade are attributed to “urgonian limestones” (e.g., anđelković, 1973; dimitrijević, 1997). in certain places, these sedimentary rocks overlie older rocks in the sequence or should occur as lenses within the turbiditic sequences (anđelković, 1954, 1956, 1973). according to anđelković (1973) typical urgonian carbonates consists of grey reef-type limestones, sandy-marly limestones and siliciclastics rich in a shallow-water fauna (caprinids, orbitolinids, corals, brachiopods, gastropods). 3. methods the studied section (fig. 2) is located in belgrade, at the košutnjak railway station (n44 4̊5’26.44 ;ˮ e20˚26’43.77 ;ˮ fig. 1c). nine samples were collected from a six metre thick limestone section overlying mainly fine-grained siliciclastic rocks. from these samples, twenty thin-sections were prepared for microfacies analysis and biostratigraphic age determination. twenty, mainly rounded to well-rounded radiolarite pebbles from intercalated conglomerates were processed with hydrofluoric acid (3%) but contain only undeterminable radiolarian faunas. during the field work orbitolinids and gastropods were detected. 4. results anđelković (1973), first studied this section, and subdivided the košutnjak carbonate succession into three levels with requienids, deposited above the fineto coarse-grained siliciclastic rocks. based on palaeontological data (requienia ammonia goldfuss, toucasia carinata matheron and orbitolina conoidea discoidea gras), anđelković (1973) he assigned them an upper barremian–aptian age. the six-metre thick succession studied in detail consists of decimetre to 0.5 metre thick-bedded greyish orbitolinid-bearing shallow-water limestone (figs. 2a, 2b). these orbitolinid-bearing beds consist mainly of bioclastic to thick bedded limestones (wackestones to packstones and grainstones). in the lower part of the shallow-water limestone section polymictic carbonate conglomerates with exotic components (volcanic clasts, radiolarites) are intercalated. besides the orbitolinids, smaller benthic foraminifera, gastropods and bivalves are distributed throughout the succession. calcareous green algae are rare and appear in some layers. g eo lo gi a c ro at ic a geologia croatica 76/3150 4.1. microfacies analysis three main microfacies types (mft) are distinguished within the shallow-marine limestones of the studied succession (figs. 2a, 2b). mft-1: bioclastic wackestone with orbitolinids (dictyoconus? pachymarginalis schroeder, mesorbitolina texana (roemer)) (figs. 3a–c). besides the age diagnostic orbitolinid foraminifera, other benthic foraminifera are represented by miliolids and textulariids, rare algal remains, gastropods, encrusted stromatoporoids (bacinellid facies – fig. 3a), and bivalves. lithoclasts (exotic clasts/radiolarite components) are subangular to well-rounded, vary in size and sorting. according to flügel (2004) and sudar et al. (2008) these kinds of sediments were deposited in a shallow subtidal to intertidal environments. the mft-1 is the most common in the lower part of the section (figs. 2a, b). mft-2: bioclastic wackestone to packstone with abundant orbitolinids (figs. 3d–g). the mft-2 is the most common in the middle and upper part of the succession (mft-2) (figs. 2a, b). dictyoconus? pachymarginalis schroeder, mesorbitolina texana (roemer), paleodictyoconus actinostoma arnaudvanneau & schroeder and daxia minima laug & peybernès are the age diagnostic benthic foraminifera. besides the orbitolinids, other skeletal grains, small benthic foraminifera such as miliolids and textulariids, gastropods and bivalve’s shells occur. in some thin-sections, ooids (fig. 3e) and subangular peloidal grainstone intraclasts are present. in sample bdz 7, together with the orbitolinids, indeterminable lituolinid large foraminifera with a complex inner structure appear. bioclastic wackeand packstones with abundant larger foraminifera (e.g. orbitolinids) are common microfacies types in inner ramp environments. the presence of imperforate foraminifera such as miliolids and agglutinated orbitolinids indicate relatively low water energy circulation with deposition of abundant carbonate mud in a lagoon (sudar et al., 2008; flügel, 2004). mft-2 corresponds to the facies of an inner middle lagoon (e.g., fig. 9l from moosavizadeh et al. (2020); fig. 10 (c, d and e) from figure 2. (a). the studied section at the košutnjak railway station. blue lines mark the intervals of the interpreted carbonate microfacies (mf1-3, sc – siliciclastic sequence). red lines mark the fault traces and their relative movement. white circles indicate sample positions (see fig. 3). photo taken in may 2019. (b). geological column and summary of the microfacies types. (c) biostratigraphic column of the main microfossils from košutnjak railway station. g eologia c roatica đorđević et al.: middle aptian orbitolinid limestones in belgrade (serbia): microfacies and depositional environment 151 rahiminejad & hassani (2015)). the mft-2 is overlain by wackestones to packstones with a significant amount of finegrained siliciclastics (figs. 3f, g). mft-3: bioclastic grainstone with large and small unsorted intraclasts, bioclasts (gastropods, bivalves, benthic foraminifera, algae, and other broken skeletal grains) (fig. 3h) beside aggregate grains, intraclasts, small ooids, and skeletal grains. aggregate grains have low degrees of roundness. small intraclasts are subrounded and rounded and show different sphericity values. large intraclasts have low roundness and low sphericity values. sediment sorting is poor. the variations in the roundness and sphericity of grains, the wide range of grain size, as well as their figure 3. microfacies of the orbitolinid-bearing sedimentary rocks from the early cretaceous (košutnjak railway station). a: stromatoporoids encrusted by bacinelid fabrics, the internal sediment is represented by wackestone with d. pachymarginalis, miliolids and textulariids. sample bdz 1. b: bioclastic wackestone with d. pachymarginalis (p), miliolids and textulariids. sample bdz 1. c: bioclastic wackestone/packstone with orbitolinids. sample bdz 2b. d-g: bioclastic wackestone with dictyoconus? pachymarginalis (p), mesorbitolina texana (t) and other benthic foraminifera. samples bdz 3, bdz 4, bdz 6 and bdz 8. h: bioclastic grainstone with coated grains. sample bdz 9. g eo lo gi a c ro at ic a geologia croatica 76/3152 poor sorting indicate mixing and reworking of the grain populations. large intraclasts with fenestral fabric suggest a low-energy protected intertidal environment. roundness and sphericity of intraclasts indicate transport within the depositional environment. poor sorting, mixing of resediments and the deposition of eroded grains together with finer grains point to deposition within tidal channels. the mft-3 occurs on top of the studied succession (figs. 2a, b). in general, all three different microfacies types are characteristic of shallow-marine depositional realms with varying depositional energies and hinterland influences. this is indicated by the different organisms including orbitolinid foraminifera, encrusted stromatoporoids, calcareous algae, ooids beside other organisms and skeletal grains. open-marine organisms from deeper-water environments are missing. orbitolinid foraminifera are common in shallow-water limestones (normal salinity and warm water), e.g. in the late early cretaceous limestones of the adriatic carbonate platform (velić, 1988;, 2007 and references therein). the orbitolinid foraminifera are associated with miliolids, which showed spectacular expansion in the middle cretaceous, proliferating in mid-latitudes (boudagher-fadel, 2008). it is also interesting to note that conical forms of orbitolinids thrive in the shallowest water (simmons et al., 2000). the microfacies changes over small-scales and short time frames together with the change in the association of grain types is according to flügel (2004) common in platform interiors and in inner to mid-ramp depositional environments, partially influenced by storm-induced currents. these small-scale changes are well developed and commonplace in jurassic and cretaceous peritidal limestones of the adriatic carbonate platform (husinec et al., 2000 and references therein). coarsening and shallowing-upwards cycles are the result of an increase in water energy which leads to the formation of grainstones composed of mixed and reworked grains. the occurrence of abundant orbitolinid foraminifera is quite common in inner ramp depositional environments. conglomerates transported by fluvial systems from the hinterland and intercalated in the shallow-marine orbitolinid limestones contain ophiolite and various radiolarite components (figs. 4a–d). in these conglomeratic layers, most of the rounded to well-rounded radiolarite components of several millimetres to centimetre-size are too small for the preparation of radiolarian faunas. still, their microfacies characteristics are well preserved. the microfacies of the radiolarite components resemble the microfacies of ribbon radiolarites as known from the sedimentary cover of the neo-tethys ocean floor or the distal continental slope (gawlick et al., 2016a, b; gawlick & missoni, 2015). however, the conglomerates overlying the orbitolinid-bearing limestones have an identical component spectrum, only differing in the larger size range of the clasts. figure 4. microfacies of different triassic radiolarite components associated with the orbitolina limestones. a: overview of the reefal limestone with mesorbitolina texana and a radiolarite component. sample bdz 2a. b: rounded late anisian to ladinian radiolarite with recrystallized radiolarians and filaments (compare gawlick et al., 2016a). sample bdz 2b. c: rounded carnian ribbon radiolarite component with remnants of organic material and recrystallized and silicified radiolarians (compare gawlick et al., 2016b). sample bdz 2a. d: rounded norian ribbon radiolarite component. sample bdz 2a. g eologia c roatica đorđević et al.: middle aptian orbitolinid limestones in belgrade (serbia): microfacies and depositional environment 153 analysis of the different rounded radiolarite pebbles from these overlying fluviatile conglomerates resulted in identification of very poorly preserved radiolarian faunas due to intense silicification, as typical for oceanic ribbon radiolarites. the radiolarians are strongly recrystallized and cannot be determined, not even to generic level, but they have a clear triassic (late anisian ladinian and late triassic) radiolarian habitus (compare fig. 4). however, despite the differences in microfacies of triassic and jurassic radiolarites, both are associated with either the neotethys ocean floor or the distal parts of the eastern passive wider adria margin, are well known and documented (gawlick et al., 2009; gawlick & missoni, 2015 and references therein). therefore, the microfacies of radiolarites can be roughly used to constrain their age, i.e. middle triassic (late anisian–ladinian), carnian-norian, rhaetian or middle jurassic. 4.2. biostratigraphy in the tethyan realm, the aptian stage is subdivided into three divisions: bedoulian (early aptian), gargasian (middle aptian) and clansayesian (late aptian) (gradstein et al., 2020). some authors (e.g., schroeder et al., 2010) subdivided the aptian into two divisions (bedoulian early aptian, gargasian with clansayesian late aptian). figure 5. microfossils from the košutnjak railway station. a, b: dictyoconus? pachymarginalis. samples bdz 1, bdz 3. axial section. c – g: mesorbitolina texana. samples bdz 3, bdz 4, bdz 8. c: axial section, d: tangential section, e–g: transverse section. h: paleodictyonus actinostoma. sample bdz 5. subaxial section. i: daxia minima. sample bdz 5. g eo lo gi a c ro at ic a geologia croatica 76/3154 (e.g., obradović & goričan, 1988; djerić et al., 2007; gawlick et al., 2020 and references therein, for dinarides; de wever et al., 1979; marcucci et al., 1994; chiari et al., 1996; gawlick et al., 2008; 2016a for albania; ozsvárt et al., 2012, for greece). also, the overlying fine-grained siliciclastic rocks, carbonate sandstones and polymictic fluviatile conglomerates consisting of exotic material were shed from the west/ southwest and deposited most probably in the late aptian. these conglomerates consist of volcanic pebbles (most probably ophiolite derived material) and various rounded radiolarite components. determinable radiolarians from the radiolarite components could not be extracted, and a detailed component analysis especially of the volcanic components is lacking. during the early cretaceous, large parts of the dinarides underwent continental weathering and the erosional products were shed either to the west in the remaining foreland basins (e.g., vranduk or bosnian basin) or to the east, i.e. the passive continental margin of the remaining eastern part of the neo-tethys ocean (missoni & gawlick, 2011b). triassic to middle jurassic ophiolites are only known from the wider adria plate, i.e. the obducted ophiolites and their ophiolitic mélanges. these ophiolites obducted in middle to early late jurassic times (for discussion see gawlick & missoni, 2019; schmid et al., 2020 and references therein), are missing on the moesian superunit. the provenance area of the ophiolite and radiolarite components is therefore undoubtedly the wider adria plate, i.e., the inner dinarides. deposition of this aptian sedimentary succession on the moesian margin (toljić et al., 2018) can therefore be excluded. 6. conclusions on the basis of the new data from the košutnjak railway station section in belgrade, the following conclusions can be drawn: deposition of the early cretaceous shallow-marine carbonates above the deeper-marine “paraflsch” succession in the belgrade area started in the aptian and not in the barremian as formerly estimated. the gargasian age of the “orbitolina”-limestones” in the belgrade area provides the first most accurate biostratigraphic age data from this carbonate sequence; radiolarite components from the conglomerates are triassic in age and derive from the obducted middle triassic to middle jurassic neo-tethys ophiolites and/or their ophiolitic mélanges on the wider adria plate; the first precise biostratigraphic dating as middle aptian combined with microfacies analysis of these shallow-marine limestones and the component spectrum in the intercalated conglomerates evidence that the early cretaceous turbiditic “paraflysch” succession was deposited on the western shelf of the remaining neo-tethys after middle to late jurassic ophiolite obduction, i.e. on the eastern part of the jurassic dinaridic orogen. acknowledgment this manuscript has been written in the framework of the igcpproject 710 (western tethys meets eastern tethys). bojana đorđević and hans-jürgen gawlick gratefully thank the “central european exchange program for university studies” (ceepus) for network mobilities (ceepus ciii-ro-0038). bojana đorđević would like to thank montanuniversität leoben for providing the facilities for this research. the research was supported by the ministry of science, technological development and innovation of the republic of serbia, contract no. 45103-68/2022-14/ 200126. we would also like to thank ioan buin the studied section, the aptian foraminiferal association was analysed in twenty thin-sections yielding dictyoconus? pachymarginalis (schroeder), mesorbitolina texana (roemer), paleodictyoconus actinostoma arnaud-vanneau & schroeder, daxia minima laug & peybernès, and nautiloculina broennimanni arnaud-vanneau & peybernès. among these, the first two are of biostratigraphic relevance. dictyoconus? pachymarginalis occurs in samples bdz 1 and bdz 3 (figs. 5a, b). according to schroeder (1964), this species is known from the lower (upper bedoulian) to the middle aptian (gargasian) (fig. 2c). the species has been reported from many localities of the neotethyan realm and was originally described from the alborz mountains (schroeder, 1964), and was also successively reported from central iran (yazdimoghadam & amiri, 2010; roozbahani, 2011; schlagintweit et al., 2013; schlagintweit & wilmsen, 2014), from nw iran (yazdi-moghadam et al., 2017), and northeast iran (taherpour khalil abad et al., 2013; bucur et al., 2019). it is worth mentioning that the species does not appear on the arabian plate (zagros zone) (schroeder et al., 2010). in europe, d.? pachymarginalis is reported from ne spain (masse et al., 1992), southern hungary (schlagintweit, 1990), and the southern apennines of italy (mancinelli & chiocchini, 2006). mesorbitolina texana occurs in all the studied samples except bdz 1 (figs. 5c-g). according to schroeder et al. (2010), m. texana had its first appearance datum (fad) at the base of the late gargasian. compared with dictyoconus? pachymarginalis and mesorbitolina texana, paleodictyonus actinostoma arnaud-vanneau & schroeder (fig. 5h) has a much wider range, i.e. from the uppermost hauterivian to the aptian (clavel et al., 2014) (fig. 2c). m. texana represents a cosmopolitan species reported from texas in the west (douglass, 1960) towards the western pacific realm, e.g., japan (iba et al., 2011). in the dinaridic realm it has been reported from various localities, e.g., croatia (husinec et al., 2000). for the wide distribution of mesorbitolinids in the mediterranean realm see moullade et al. (1985, fig. 2). the co-occurrence of dictyoconus? pachymarginalis (schroeder) and mesorbitolina texana (roemer) is known from many localities in the western tethyan realm up to the middle east area (e.g., schlagintweit, 1990; mancinelli & chiocchini, 2006; schroeder et al., 2010; schlagintweit et al., 2013; schlagintweit & wilmsen, 2014) and indicates an upper gargasian (middle aptian) age for the orbitolinid-bearing beds of the studied section. 5. discussion in general, the short-lasting deposition of shallow-water “orbitolina” limestones above marine siliciclastic sedimentary rocks and below a series of fine grained siliciclastic rocks with intercalated polymictic conglomerates is most probably connected with the long-term falling sea-level during the aptian (ogg et al., 2004). this would imply that the underlying marine siliciclastics were deposited during the lower aptian. the radiolarite components from the conglomerates intercalated in the “orbitolina” limestones can be attributed by their microfacies characteristics to the middle and late triassic, i.e., the whole ribbon radiolarite sequence of the neo-tethys ocean floor. these triassic ribbon radiolarites are known from the west-vardar ophiolites (in the sense of schmid et al., 2008; dinaridic ophiolite belt of dimitrijević, 1997) and the mirdita ophiolites in albania g eologia c roatica đorđević et al.: middle aptian orbitolinid limestones in belgrade (serbia): microfacies and depositional environment 155 cur (cluj-napoca) and anonymous reviewers for their constructive comments and suggestions on the manuscript. the reviewers provided helpful comments that improved this manuscript. references anđelković, m. (1954): l’urgonien et l’albien dans la zone crétacée de topola— drača (šumadija — serbie).– geološki anali balkanskoga poluostrva, 22, 27–79. (in serbian with french summary). anđelković, m. (1956): la constitution geologique et tectonique des montagnes: de gledici (serbie centrale šumadija).– geološki anali balkanskoga poluostrva, 24, 31–184. (in serbian with french summary). anđelković, m. (1973): geology of the mesozoic in the vicinity of belgrade.– geološki anali balkanskoga poluostrva, 38, 1–142. (in serbian with english summary). blanchet, r., cadet, j.p. & charvet, j. (1970): sur l’existence d’unités intermédiaires entre la zone du haut karst et l’unité du flysch bosniaque, en yougoslavie: la sous-zone prékarstique.– bulletin de la société géologique de france, 12/2, 227–236. doi: 10.2113/gssgfbull.s7-xii.2.227 boudagher-fadel, m. k. (2008): evolution and geological significance of larger benthic foraminifera.– developments in palaeontology and stratigraphy, elsevier, 21, 1–544. doi: 10.2307/j.ctvqhsq3 bragin, n., bragina, l., gerzina, n., djerić, n. & schmid, s.m. (2019): new radiolarian data from the jurassic ophiolitic mélange of avala mountain (serbia, belgrade region).– swiss journal of geosciences, 112, 235–249. doi: 10.1007/ s00015-018-0313-8 bucur i.i., yarahmadzahi, h. & mircescu c.v. (2019): the lower cretaceous tirgan formation in the gelian section (kopet dagh, north iran): microfacies, microfossils, and their biostratigraphic significance.– acta palaeontologica romaniae v, 15/1, 13–33. doi: 10.35463/j.apr.2019.01.02 chiari, m., marcucci, m., cortese, g., ondrejickova, a. & kodra, a. (1996): triassic radiolarian assemblages in the rubik area, and cukali zone, albania.– ofioliti, 21, 77–84. clavel, b., charollais, j., busnardo, j., granier, b., conrad, m., desjacques, p. & metzger, j. (2014): la plate-forme carbonatée urgonienne (hauterivien supérieur – aptien inférieur) dans le sud-est de la france et en suisse: synthèse.– archives des sciences, 67, 1–100. csontos, l. & vörös, a., (2004): mesozoic plate tectonic reconstruction of the carpathian region.– palaeogeography, palaeoclimatology, palaeoecology, 210, 1–56. doi: 10.1016/j.palaeo.2004.02.033 de wever, p., sanflippo, a., riedel, w. r. & gruber b. (1979): triassic radiolaria from greece, sicily and turkey.– micropaleontology, 25/1, 75–110. dimitrijević, m.d. (1997): geology of yugoslavia.– geological institute gemini, special publication, belgrade, 187. dimitrijević, m.n. & dimitrijević, m.d. (1976): lower cretaceous complex of the central vardar subzone.– in: 8th yugoslavian geological congres – ljubljana 1976, 3, 59–72. dimitrijević, m.n. & dimitrijević, m.d. (1987): the titova mitrovica flysch.– in: dimitrijević, m.n. & dimitrijević, m.d. (eds.): the turbiditic basins of serbia, serbian academy of sciences and arts department of natural and mathematical sciences, 61, 25–64. djerić, n., gerzina, n., & schmid, s. (2007): age of the jurassic radiolarian chert formation from the zlatar mountain (sw serbia).– ofioliti, 32, 101–108. douglass, r.c. (1960): the foraminiferal genus orbitolina in north america.– geological survey professional papers, 333, 1–52. filipović, i., rodin, v., pavlović, z., milićević, m. & atin, b. (1979): osnovna geološka karta sfrj 1:100000. tumač za list obrenovac [basic geological map of sfry 1:100.000, geology of obrenovac sheet – in serbian].– savezni geološki zavod, beograd, federal geologic survey, belgrade. flügel, e. (2004): microfacies of carbonate rocks. analysis, interpretation and application.– springer, berlin, 976 p. gardin, s., kici, v., marroni, m., mustafa, f., pandolfi, l., pirdini, a. & xhomo, a. (1996): lithoand biostratigraphy of the firza flysch, ophiolite mirdita nappe, albania.– ofioliti, 21, 47–54. gawlick, h.j. & missoni, s. (2015): middle triassic radiolarite pebbles in the middle jurassic hallstatt mélange of the eastern alps: implications for triassic–jurassic geodynamic and paleogeographic reconstructions of the western tethyan realm.– facies, 61, 13–19. doi: 10.1007/s10347-015-0439-3 gawlick, h.j. & missoni, s. (2019): middle-late jurassic sedimentary mélange formation related to ophiolite obduction in the alpine-carpathian-dinaridic mountain range.– gondwana research, 74, 144–172. doi: 10.1016/j.gr.2019.03.003 gawlick, h.j., frisch, w., hoxha, l., dumitrica, p., krystyn, l., lein, r., missoni, s. & schlagintweit, f. (2008): mirdita zone ophiolites and associated sediments in albania reveal neotethys ocean origin.– international journal earth science, 97, 865–881. doi: 10.1007/s00531-007-0193-z gawlick, h.j., goričan, š., missoni, s., dumitrica, p., lein, r., frische, w. & hoxha, l. (2016a): middle and upper triassic radiolarite components from the kcira-dushi-komani ophiolitic mélange and their provenance (mirdita zone, albania).– revue de micropaléontologie, 59/4, 359–380. doi: 10.1016/j. revmic.2016.03.002 gawlick, h.j., missoni, s., suzuki, h., & sudar, m. (2016b): triassic radiolarite and carbonate components from a jurassic ophiolitic mélange (dinaridic ophiolite belt).– swiss journal of geosciences, 9/3, 473–494. doi: 10.1007/ s00015-016-0232-5 gawlick, h.j., sudar, m., missoni, s., aubrecht, r., schlagintweit, f., jovanović, d., & mikuš, t. (2020): formation of a late jurassic carbonate platform on top of the obducted dinaridic ophiolites deduced from the analysis of carbonate pebbles and ophiolitic detritus in southwestern serbia.– international journal of earth sciences, 109, 2023–2048. doi: 10.1007/s00531-020-01886-w gawlick, h.j., sudar, m., suzuki, h., djerić, n., missoni, s., lein, r. & jovanović, d. (2009): upper triassic and middle jurassic radiolarians from the ophiolitic melange of the dinaridic ophiolite belt, sw serbia.– neues jahrbuch für geologie und paläontologie, 253, 293–311. doi: 10.1127/00777749/2009/0253-0293 gradstein, f., ogg, j.g., schmitz m.d. & ogg, g.m. (2020): a geological time scale 2020.– elsevier, 1390 p. husinec, a., velić, i., fuček, l., vlahović, i., matičec, d., oštrić, n. & korbar, t. (2000): mid cretaceous orbitolinid (foraminiferida) record from the islands of cres and lošinj (croatia) and its regional stratigraphic correlation.– cretaceous research, 21, 155–171. doi: 10.1006/cres.2000.0203 iba, y., sano, s., & miura, t. (2011): orbitolinid foraminifers in the northwest pacific: their taxonomy and stratigraphy.– micropaleontology, 57/2, 163–171. doi: 10.47894/mpal.57.2.04 karamata, s. (2006): the geological development of the balkan peninsula related to the approach, collision and compression of gondwanan and eurasian units.– in: robertson, a. h.f. & mountrakis, d. (eds.): tectonic development of the eastern mediterranean region. geological society london special publications, 260, 155–178. doi: 10.1144/gsl.sp.2006.260.01.07 kostaki, g., kilias, a., gawlick, h.-j. & schlagintweit, f. (2013):?kimmeridgian-tithonian shallowwater platform clasts from mass flows on top of the vardar/axios ophiolites.– bull. geol. soc. greece, 47/1, 184–193. doi: 10.12681/ bgsg.10923 krische, o., gorican, s. & gawlick, h.-j. (2014): erosion of a jurassic ophiolitic nappe-stack as indicated by exotic components in the lower cretaceous rossfeld formation of the central northern calcareous alps (austria).– geologica carpathica, 65, 3–24. doi: 10.2478/geoca-2014-0001 kukoč, d., goričan, š. & košir, a. (2012): lower cretaceous carbonate gravityflow deposits from the bohinj area (nw slovenia): evidence of a lost carbonate platform in the internal dinarides.– bulletin de la société géologique de france, 183/4, 383–392. doi: 10.2113/gssgfbull.183.4.383 mancinelli, a. & chiocchini, m. (2006): cretaceous benthic foraminifers and calcareous algae from monte cairo (southern latium, italy).– bolletino della società paleontologica italiana, 45/1, 91–113. marcucci, m., kodra, a., pirdeni, a., & gjata, t. (1994): radiolarian assemblages in the triassic and jurassic cherts of albania.– ofioliti, 19, 105–114. marković, b., veselinović, m., anđelković, j., stevanović, p., roglić, č. & obradinović, z. (1985): osnovna geološka karta sfrj 1:10000. tumač za list beograd [basic geological map of sfry 1:10000, geology of beograd sheet – in serbian].– savezni geološki zavod, beograd, federal geologic survey, belgrade. marković, b., veselinović, m., obradinović, z., anđelković, j., atin, b. & kostadinov, d. (1984): osnovna geološka karta sfrj 1:10000, list beograd [basic geological map of sfry 1:100.000, beograd sheet – in serbian].– savezni geološki zavod, beograd, federal geologic survey, belgrade. marroni, m., pandolfi, l., onuzi, k., palandri, s. & xhomo, a. (2009): ophiolite – bearing vermoschi flysch (albanian alps, northern albania): elements for its correlation in the frame of dinaric-hellenic belt.– ofioliti, 34, 95–108. masse, j.p, arias, c. & vilas, l. (1992): stratigraphy and biozonation of a reference aptian-albian p.p. tethyan carbonate platform succession: the sierra dell carche series (oriental prebetic zone – murcia, spain).– in: kollmann, h.a. & zapfe, h. (eds.): new aspects on tethyan cretaceous fossil assemblages. schriftenreihe der erdwissenschaftlichen kommissionen der österreichischen akademie der wissenschaften, 9, 201–222. doi: 10.1007/978-3-7091-5644-5_12 meço, s. & aliaj, s. (2000): geology of albania.– gebrüder borntraeger, berlin, 246 p. mikes, t., christ, d., petri, r., dunkl, i., frei, d., báldi-beke, m., reitner, j., wemmer, k., hrvatović, h. & von eynatten, h. (2008): provenance of the bosnian flysch.– swiss journal of geosciences, 101/1, 31–54. doi: 10.1007/s00015-008-1291-z missoni, s. & gawlick, h.j. (2011a): jurassic mountain building and mesozoiccenozoic geodynamic evolution of the northern calcareous alps as proven in the g eo lo gi a c ro at ic a geologia croatica 76/3156 berchtesgaden alps (germany).– facies, 57, 137–186. doi: 10.1007/s10347-0100225-1 missoni, s. & gawlick, h.j. (2011b) evidence for jurassic subduction from the northern calcareous alps (berchtesgaden; austroalpine, germany).– international journal of earth sciences, 100, 1605–1631. doi: 10.1007/s00531-010-0552-z moullade, m., peybernès, b., rey, j. & saint-marc, p. (1985): biostratigraphic interest and paleobiogeographic distribution of early and mid-cretaceous mesogean orbitolinids (foraminiferida).– journal of foraminiferal research, 15/3, 149–158. doi: 10.2113/gsjfr.15.3.149 moosavizadeh, m.a., zand-moghadam, h. & rahiminejad, a.h. (2020): palaeoenvironmental reconstruction and sequence stratigraphy of the lower cretaceous deposits in the zagros belt, sw iran.– boletin de la sociedad geologica mexicana, 72/2, 1–32. doi: 10.18268/bsgm2020v72n2a060919 nirta, g., moratti, g., piccardi, l., montanari, d., catanzariti, r., carras, n. & papini, m. (2015): the boeotian flysch revisited: new constraints on ophiolite obduction in central greece.– ofioliti, 40/2, 107–123. obradović, j. & goričan, š. (1988): siliceous deposits in yugoslavia: occurrences, types, and ages.– in: hein, j.r. & obradović j. (eds.): siliceous deposits of the tethys and pacific regions, 51–64. doi: 10.1007/978-1-4612-34944_4 ogg, j.g., agterberg, f.p. & gradstein, f.m. (2004): the cretaceous period.– in: gradstein, f., ogg, j. & smith, a. (eds.): a geologic time scale 2004. cambridge university press, 344–383. doi: 10.1017/cbo9780511536045.020 ozsvárt, p., dosztály, l., migiros, g., tselepidis, v. & kovács, s. (2012): new radiolarian biostratigraphic age constraints on middle triassic basalts and radiolarites from the inner hellenides (northern pindos and othris mountains, northern greece) and their implications for the geodynamic evolution of the early mesozoic neotethys.– international journal of earth sciences, 101, 1487–1501. doi: 10.1007/s00531-010-0628-9 pavlović, z., marković, b., atin, b., dollć, d., gagić, n., marković, o., dimitrijević, m. & vuković, m. (1979): osnovna geološka karta sfrj 1:10000. tumač za list obrenovac [basic geological map of sfry 1:10000, geology of smederevo sheet – in serbian].– savezni geološki zavod, beograd, federal geologic survey, belgrade. rahiminejad, a.h. & hassani, m.j. (2015): depositional environment of the upper cretaceous orbitolinid-rich microfacies in the kuh-e mazar anticline (kerman province, central iran).– historical biology: an international journal of paleobiology, 28/5, 597–612. doi: 10.1080/08912963.2014.998667 robertson, a.h.f., ionescu, c., hoeck, v., koller, f., onuzi, k., bucur, i.i. & ghega, d. (2012): emplacement of the jurassic mirdita ophiolites (southern albania): evidence from associated clastic and carbonate sediments.– international journal of earth sciences, 101/6, 1535–1558. doi: 10.1007/s00531-0100603-5 roozbahani, p.r. (2011): lithostratigraphy and biostratigraphy of the lower cretaceous of the jalmajird area (northeast of khomeyn, central iran basin), iran.– geo.alp., 9, 48–58. schlagintweit, f. & wilmsen, m. (2014): orbitolinid biostratigraphy of the top taft formation (lower cretaceous of the yazd block, central iran).– cretaceous research, 49, 125–133. doi: 10.1016/j.cretres.2014.02.016 schlagintweit, f. (1990): microfaunistic investigations of hungarian urgonian limestones (barremian aptian).– acta geologica hungarica, 33/1–4, 3–12. schlagintweit, f., bucur, i.i., rashidi, k. & saberzadeh, b. (2013): praeorbitolina clavelii n. sp. (benthic foraminifera) from the lower aptian (bedoulian) of central iran.– carnets de géologie-notebooks on geology, 4, 255– 272. schlagintweit, f., gawlick, h.-j., missoni, s., hoxha, l., lein, r. & frisch w. (2008): the eroded late jurassic kurbnesh carbonate platform in the mirdita ophiolite zone of albania and its bearing on the jurassic orogeny of the neotethys realm.– swiss journal of geosciences, 101, 125–138. doi: 10.1007/ s00015-008-1254-4 schlagintweit, f., gawlick, h-j., lein, r., missoni, s. & hoxha, l. (2012a): onset of an aptian carbonate platform overlying a middle-late jurassic radiolaritic-ophiolitic mélange in the mirdita zone of albania.– geologia croatica, 65/1, 29–44. doi: 10.4154/gc.2012.02 schlagintweit, f., krische, o. & gawlick, h.-j. (2012b): first findings of orbitolinids (larger benthic foraminifera) from the early cretaceous rossfeld formation (northern calcareous alps, austria).– jahrbuch der geologischen bundesanstalt, 152, 145–158. schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpinecarpathian-dinaride-orogenic system: correlation and evolution of tectonic units.– swiss journal of geosciences, 101, 139–183. schmid, s.m., fügenschuh, b., kounov, a., matenco, l., nievergelt, p., oberhänsli, r., pleuger, j., schefer, s., schuster, r., tomljenović, b., ustaszewski, k. & van hinsbergen, d.j.j. (2020): tectonic units of the alpine collision zone between eastern alps and western turkey.– gondwana research, 78, 308–374. doi: 10.1016/j.gr.2019.07.005 schroeder, r. (1964): orbitoliniden-biostratigraphie des urgons nordöstlich von teruel (spanien).– neues jahrbuch für geologie und paläontologie monatshefte, 462–472. schroeder, r., buchem, f.s.p., van cherchi, a., baghbani, d., vincent, b., immenhauser, a. & granier, b. (2010): revised orbitolinid biostratigraphic zonation for the barremian-aptian of the eastern arabian plate and implications for regional stratigraphic correlations.– geoarabia spec. pub., 4, 49–96. simmons, m.d., whittaker, j.e. & jones, r.w. (2000): orbitolinids from cretaceous sediments of the middle east – a revision of the f.r.s. henson and associates collection.– in hart, m.b., kaminski, m.a. & smart, c.w. (eds.): proceedings of the fifth international workshop on agglutinated foraminifera. grzybowski foundation special publication, 7, 411–437. sladić-trifunović, m. (1998): on the senonian rudist-bearing sediments in yugoslavia.– geobios, 22, 371–384. sudar, m, jovanović, d, maran, a, & polavder s. (2008): late barremian– early aptian urgonian limestones from the south–eastern kučaj mountains (carpatho–balkanides, eastern serbia).– geološki anali balkanskoga poluostrva, 69, 13–30. doi: 10.2298/gabp0869013s taherpour khalil abad, m., schlagintweit, f., vaziri, s.h., aryaei, a.a. & ashouri, a.r. (2013): balkhania balkhanica mamontova, 1966 (benthic foraminifera) and kopetdagaria sphaerica maslov, 1960 (dasycladalean alga) from the lower cretaceous tir-gan formation of the kopet dagh mountain range (ne iran) and their palaeobiogeographic significance.– in: bucur, .i.i. & fürsich, f.t. (eds.): recent advances in fossil algae, facies, 59/1, 267–285. toljić, m., mațenco, l., stojadinović, u., willingshofer, e. & ljubović-obradović, d. (2018): understanding fossil fore-arc basins: inferences from the cretaceous adriaeurope convergence in the ne dinarides.– global and planetary change, 171, 167–184. doi: 10.1016/j.gloplacha.2018.01.018 velić, i. (1988): lower cretaceous benthic foraminiferal biostratigraphy of the shallow-water carbonates of the dinarides.– revue de paleobiologie, vol. spec. 2, benthos ‘86, 467–475. velić, i. (2007): stratigraphy and palaeobiogeography of mesozoic benthic foraminifera of the karst dinarides (se europe).– geologia croatica, 60/1, 1–113. yazdi-moghadam, m. & amiri, f. (2010): lower cretaceous agglutinated larger benthic foraminifera from the sarvestan section, south of esfahan, iran.– in: the 1st international applied geological congress – iran 2010, department of geology, azad university-mashad branch, 976–980. zelić, m., marroni, m., pandolfi, l. & trivić, b. (2010): tectonic setting of the vardar suture zone (dinaric-hellenic belt): the example of the kopaonik area (southern serbia).– ofioliti, 35, 49–69. 2019 | 72/3 | 215–221 | 10 figs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the republic of macedonia is rich in inorganic materials with a wide range of potential use and application, including diatomaceous earth (reka, et al., 2014; reka et al., 2017), trepel (a biogenetic rock) (pavlovski et al., 2011; cekova et al., 2013), pumicite (cekova et al., 2013), dolomite (makreski et al., 2003; jovanovski et al., 2012), quartzite (jovanovski et al., 2012), bentonite (šontevska et al., 2007) and granite (jovanovski et al., 2012). perlite, originates from the term perlstein (pearl stone) coined by german petrologists in the nineteenth century for a certain rhyolitic, glassy rock with numerous concentric cracks which on fragmentation yielded pieces vaguely resembling pearls (evans, 1993). perlite was originally identified by its vitreous, pearly lustre and characteristic curved (onion-skin texture) perlitic fractures (breese, 1984; kogel et al., 2006; koukouzas, 2006). perlite is one of the natural volcanic aluminosilicate glasses (rhyolitic rocks) which formed by the rapid cooling of viscous lava or magma. these include obsidian, perlite, pitchstone, and hydrated volcanic ash or “pumicite” (breese, 1984; kogel et al., 2006; koukouzas, 2006; kongkachuichay and lohsoontorn, 2006). the main characteristic of perlite is the content of chemically bonded water. perlites are classified into three types depending on their water contents as obsidian (water content less than 2 wt. %), perlite (2–5 wt.%) and pitchstone (water content > 5 wt.%). upon heating (760–900 ºc), perlite be chemical, mineralogical and structural features of native and expanded perlite from macedonia arianit a. rekaa,*, blagoj pavlovskib, kiril lisichkovb, ahmed jasharia, blazo boevc, ivan boevc, maja lazarovac, volkan eskizeybekd, ayhan orald, gligor jovanovskie and petre makreskif a university of tetovo, faculty of natural sciences and mathematics, ilinden n.n., 1200 tetovo, republic of macedonia b ss. cyril and methodius university, faculty of technology and metallurgy, ruger boskovic bb, 1000 skopje, republic of macedonia c goce delčev university, faculty of natural and technical sciences, blvd. krste misirkov 10-a, 2000 štip, republic of macedonia d çanakkale onsekiz mart university, department of materials science and engineering, campus of terzioglu 17100 çanakkale, turkey e macedonian academy of sciences and arts, research center for environment and materials, bul. krste misirkov 2, 1000, skopje, republic of macedonia f institute of chemistry, faculty of natural sciences and mathematics, ss. cyril and methodius university, arhimedova 5, 1000 skopje, republic of macedonia; (*corresponding author: arianit.reka@unite.edu.mk) doi: 10.4154/gc.2019.18 abstract the physico-mechanical, chemical and mineralogical characteristics of volcanic glass (perlite) from the mariovo region (macedonia) as well as the mineralogical changes that occur during its thermal treatment were investigated to demonstrate its utilization for industrial use. the native perlite was characterized by chemical analysis, x-ray powder diffraction (xrpd), infrared (ir) spectroscopy, thermal analysis (tga/dta), scanning electron microscopy (sem-edx), transmission electron microscopy (tem), and solidstate nmr. the chemical examination suggests that the perlite represents an acidic volcanic rock with a high percentage of sio2 (72.45%), high in alkali metal oxides (4.21 wt.% k2o, 3.56 wt.% na2o), with a loss of ignition 3.54 wt.%. results from the xrpd indicated major amorphous behaviour, with low amounts of feldspars, quartz, and cristobalite. sem examinations revealed glassy structure with presence of certain pores (dimensions ranging from 50–100 μm). the determined expansion coefficient was 20 times its original volume. xrpd of expanded perlite compared to the native perlite depicted new intensive peaks of cristobalite. sem and tem revealed irregular morphology with broken or ragged edges. on the basis of the chemical and mineralogical composition, the studied perlite is classified as an appropriate material suitable as ceramic flux to lower the sintering temperature. comes pyroplastic and expands and increases 20 fold in volume. bound water vaporizes and creates numerous bubbles that provide the exceptional characteristics of the perlite: a porous structure (increased porosity) and low weight (decreased density). such material is known as expanded perlite; moreover, it expresses a low thermal conductivity, considerable heat resistance and acts as a very good sound absorber. the main components of perlite are the oxides such as sio2 (70–75 wt.%), al2o3 (12–18 wt.%) as well as the alkaline oxides (k2o, na2о). perlite also contains small amounts of other oxides such as fe2o3, cao, mgo and tio2 (roulia et al., 2006; burriesci et al., 1985; kaufhold et al., 2014; varga et al., 2015). perlites, either as native materials or expanded, due to their properties (low density, high porosity, chemical inertness and non-toxicity), are versatile materials and used for the preparation of catalysts, ceiling tiles, pipe insulation, gypsum wallboard, cryogenic insulation, fillers, materials for filtering (filters), aggregates for light cement, removal of heavy metals and adsorption of particulates from the atmosphere, thermal insulators, absorption of oil, roof panels, foams, fire retardants, brick products, horticulture, production of container glass, in the ceramic industry (as a component in the ceramic mass), microorganism carriers, materials for improving the mechanical and thermal properties of cement mortar, and glaze products (ahmadia et al, 2018; sodeyama et al., 1999; zafirovski et al., 1987; vijayaraghavan and raja, 2014; rodriguez et al., 2016). the application of article history: manuscript received january 31, 2019 revised manuscript accepted september 23, 2019 available online october 31, 2019 keywords: perlite; volcanic rocks; chemical and mineralogical characterization; expansion coefficient g eo lo gi a c ro at ic a geologia croatica 72/3216 perlite for these purposes depends on the physico-chemical characteristics, as well as from its mineralogical composition. perlite mines are located in several countries around the world, with the leading producers being turkey, greece, usa, japan, italy and hungary (sodeyama et al., 1999; sodeyama and sakka, 2005). it is estimated that the republic of macedonia contains over 1.18 million tons of perlite (spasovski and spasovski, 2012), found in the tertiary volcanics. the major area is at nidze mountain, close to the border with greece, where perlite is associated with pliocene latite in the gradesnica deposit (kogel et al., 2006). preparation for excavation was planned in the late 1990s with production expected to reach 80 ktpy (harben and kuzvart, 1997), but no actual extraction occurred. the aim of this study was to determine, for the first time, the physico-mechanical, chemical and mineralogical characteristics of perlite from the mariovo region, and to investigate the mineralogical changes that occur during thermal treatment. therefore, our goal was to resolve the most appropriate valorization of this volcanic rock from this locality as well as to determine its expansion coefficient. 2. materials and methods the perlite was collected from the mariovo region (fig. 1). the samples were fine-grained of a white to greyish colour, with white phenocrysts, and granulation of 0.2–0.5 mm was used for the measurements. the specific gravity of the natural perlite was determined by pycnometer (as per the standard d 854 – 02 – standard test methods for specific gravity of soil solids by water pycnometer1), while the compressive strength was determined with an automatic press (automax 5, controls). the chemical composition of the volcanic glass was determined using classical silicate analysis. crude perlite was melted in a mixture of carbonates (na2co3 and k2co3), whereas the percentages of the various oxides present in the material were determined by complexometric titration (kirschenbaum, 1983). the alkali metal oxides (na2o and k2o) were determined by flame photometry using an evans electroselenium ltd 410 instrument. the mineralogical characterization was carried out using x-ray powder diffraction (xrpd), thermal analysis (tga/dta), scanning electron microscopy (sem-edx), transmission electron microscopy (tem) and infrared spectroscopy (ir). xrpd analysis was performed on a rigaku ultima iv x-ray diffractometer equipped with a d/tex high-speed 1-dimenzional detector using cukα radiation (λ = 1.54178 å) in 2θ range from 5 to 60°. the accelerating voltage and the current power were set to 40 kv and 40 ma, respectively. dta/tga analyses of the volcanic glass were performed using a stanton redcroft apparatus, under the following experimental conditions: temperature range 20–1000 °c; heating rate 10 °c/min and a thermal treatment duration time of 98 min; sample mass of 19.085 mg, with a ceramic pot as a material carrier. the optical microscopy measurements were conducted on a transmission polarizing microscope sm-pol, leitz, wetzlar, germany. a scanning electron microscope vega3 lmu tescan instrument coupled with energy dispersive x-ray spectroscopy (inca energy 250 microanalysis system) was used to quantitatively analyze the products. the voltage of the se detector was set to 20 kv. a jeol 2100 transmission electron microscope (tem) was used to obtain tem photographs of the volcanic glass. the perkin-elmer ftir system 2000 interferometer was engaged to record the ir spectra in 4000–500 cm–1 range using the kbr pellet method. solid state nmr characterizations of volcanic glass were carried out using a jeol 400 mhz nuclear resonance spectrophotometer. in order to determine the expansion coefficient of this volcanic glass, crude perlite was initially dried at 100 ˚c and subsequently subjected to thermal treatment at 850 ̊ c at which the water trapped in the structure vaporized and escaped resulting in the expansion of the material. the expansion coefficient of perlite is equal to 20 times its initial volume (fig. 2, right). the bulk density of 62 g/dm3 (0.062 g/cm3) was determined for the expanded perlite. figure 1. a geological map of macedonia pinpointing the locality (black circle) from where the perlite was excavated. g eologia c roatica reka et al.: chemical, mineralogical and structural features of native and expanded perlite from macedonia 217 3. results and discussion 3.1. physico-mechanical properties of perlite the perlite was excavated from the mariovo region (fig. 1). the following physico-mechanical properties were determined for the native perlite (fig. 2, left): white to light grey colour, odourless, with clearly visible black particles of glass. the specific gravity of the natural perlite was determined by pycnometer (standard d 854 – 02 standard test methods for specific gravity of soil solids by water pycnometer) as 2.23–2.40 g/cm3, while the compressive strength was in the range from 4.20 to 5.30 mpa. the process of expanding the natural perlite was monitored by expansion in industrial vertical expansion furnaces. in order to obtain the maximum expansion at this grain size (0.2–0.5 mm), perlite was preheated at 350–400 °c for a period of 4-5 seconds and afterwards heated at 850 °c in the high temperature furnace for 2-3 seconds. 3.2. chemical analysis of perlite the chemical composition of the volcanic rock (table 1) was determined with the classical chemical silicate analysis. the loss of ignition (loi) was determined while heating perlite at 1000 ˚c for a period of 1 hour; loi was 3.54% and lies within the typical range for perlites (3-5%). the results obtained from the chemical composition of perlite indicate that the analyzed perlite represents an acidic volcanic rock with a high percentage of sio2 (72.48%) and substantial amounts of al2o3 (13.15%). the alkali metal oxides (k2o and na2o) are present at 4.21% and 3.56% respectively, (representing high percentages) indicates that the analyzed raw material is suitable for container glass. 3.3. x-ray powder diffraction analysis of the native and expanded perlite results of the xrpd analysis of the perlite (fig. 3, top) depicts the amorphous behaviour of the sample manifested by the appearance of one complex “hump” widely positioned between 15 and 30° (2θ) with the most maxima peaking in the 22–26.7° range as a result of the high percentage of the aluminosilicate glass phase associated by small amounts of crystalline phases. the small quantities of the crystalline phases are mainly represented by feldspars, quartz and cristobalite. feldspars are represented as plagioclases (13.50°, 25.76°, 29.98°, 33.64°, 35.40°, 42.66°, 49.74°), k, na-feldspars (23.70°, 27.40°, 27.66°), and microcline (27.66, 29.49, 50.58). the less pronounced presence of sio2 polymorphs figure 2. natural (crude) perlite from mariovo region (up). comparison of the volume of the same mass (3.1 g) of perlite and expanded perlite (down). the volume of 2.5 ml of native perlite versus the volume of 50 ml of the expanded perlite. table 1. chemical composition of perlite. oxides mass % sio2 72.48 al2o3 13.15 fe2o3 1.23 tio2 0.15 cao 1.13 mgo 0.35 k2o 4.21 na2o 3.56 loi 3.54 total 99.80 figure 3. xrpd analysis of native perlite (top) and expanded perlite (bottom). are represented by α-quartz (26.67°) and cristobalite (21.94°). the presence of crystalline modifications in the volcanic rock is correlated to the origin of perlite, with more crystallites being formed in the slow cooling of the lava. results of the xrpd analysis of the expended perlite (fig. 3, bottom) again demonstrated the amorphous behaviour of the sample manifested by the appearance of one complex “hump” extended between 15 and 30° (2θ) with the most maxima peaking in the 22–26.7° range as a result from the high percentage of aluminosilicate glass. compared to the native perlite, the expanded perlite shows an evident increase in the amount of cristobalite (21.94°, 28.44, 31.40, 36.00) present. 3.4. infrared spectral analysis of the native and the expanded perlite the ir spectrum of native perlite (fig. 4, top) exhibits an absorption band at 786 cm-1 attributed to the bending vibrations of the si-o-si framework, whereas the band at 1078 cm-1 is a result of g eo lo gi a c ro at ic a geologia croatica 72/3218 the stretching vibrations of the si-o-al units (sodeyama et al., 1999; makreski et al., 2009). the band at 1644 cm-1 is due to bending vibrations from the absorbed water (roulia et al., 2006; varuzhanyan et al., 2006; makreski et al., 2009), whereas the band at 3650 cm-1 is due to the stretching vibration of the absorbed water molecules (sodeyama et al., 1999; li and tomozawa, 1994). as results of the thermal treatment and water loss during the expansion of perlite, the bands at 1644 cm-1 and 3650 cm-1 that were previously discussed at the native perlite (fig. 4, bottom), bands due to bending vibrations from the absorbed water and the stretching vibration of the absorbed water molecules (roulia et al., 2006; varuzhanyan et al., 2006; makreski et al., 2009), as expected, are missing in the ir spectrum of the expanded perlite (fig. 4, bottom). the band at 785 cm-1 and 1047 cm-1 are ascribed to the si-o stretching vibrations of si-o-si and si-o-al, respectively (sodeyama et al., 1999). 3.5. optical microscopy the results of the light microscopy demonstrated the sample composition of an isotropic glassy mass (fig. 5) with the presence of glassy-isotropic fine-grained particles/microlites (0.03–0.1 mm). in the fine-grained mass of the raw material, besides the microlites, phenocrysts of quartz with dimensions varying from 2 to 3 mm are observed, corroded in the mass itself (fig. 5). 3.6. scanning electron microscopy (sem-edx) and transmission electron microscopy (tem) of the native and expanded perlite the results from the sem of crude perlite (figs. 6a,b) confirm the findings from the optical microscopy. the evidence of open pores and the fluid character of the glassy phase are depicted in fig. 6a, whereas fig. 6b illustrates compact glass mass of the perlite with presence of the tiny crystals. scanning electron microscopy (sem) was also employed to study the induced material alteration by the expansion process (fig. 6c, d). during the heat treatment, the grains start to soften superficially and the outer shell becomes smooth, while the water trapped in the thin layers escaped resulting in expansion of the grain. the grains explode vigorously with considerable morphological alteration (roulia et al., 2006). the expanded perlite particles exhibited irregular morphology with broken or ragged edges. the perlite particles exhibit some internal cellular structure. the microstructure of the expanded perlite is characterized by vast open pores (small channels which form a dense network) and some isolated holes and cells. according to the area spectrum of edx analysis, the presence of o, na, al, si and k elements in the structure of the native perlite was quantitatively determined (fig. 7). namely, the chemical composition and weight percentage of the elements in perlite (o: 51.40%, na: 2.00%, al: 6.72%, si: 35.03%, and k: 4.84%) correspond to the prevailing glassy phase in perlite (fig. 7a, c). on the other hand, the chemical composition obtained from carefully selected spheres with dimensions smaller than 1–5 μm (o: 63.19%, al: 7.04%, and si: 29.76%) served as evidence for the presence of crystalline aluminosilicates in perlite (fig. 7b, d). the results from the transmission electron microscopy of the crude perlite show that the main mass of perlite is volcanic glass (fig. 8). tem also shows that the glassy mass of native perlite nests presence of very fine crystalline phases, with dimensions ranging from 10–50 nm (fig. 8). these results correspond to figure 4. ir spectrum of native perlite (top) and expanded perlite (bottom). figure 5. optical photomicrographs of perlite: а) 2-3 mm quartz phenocryst (1) and microlite (3) embedded in the glassy mass (2) with indications of corrosion of the crystal; b) isotropic microlites (3) with prevalence of turbulent, fluidal movement (4) of the glassy phase (2); c) corroded phenocryst (1) from the glassy mass; d) microlite (3) and corroded phenocrysts (1) of pigmented isotropic minerals (most likely carriers of fe, ti and mn) from the glassy mass. figure 6. sem photomicrographs of crude perlite (a,b) and the expanded perlite (c,d). perlite shows open pores (1), glassy mass (2), and tiny crystals (3). g eologia c roatica reka et al.: chemical, mineralogical and structural features of native and expanded perlite from macedonia 219 figure 7. sem photomicrographs of native perlite: the glassy/amorphous (a) and crystalline phase (b) and the corresponding element content as determined by eds (c, d). figure 8. tem photomicrographs of the glassy mass in perlite (left) and the crystalline phases in the volcanic glass (right). figure 9. the dta/tga curves of native perlite. g eo lo gi a c ro at ic a geologia croatica 72/3220 xrpd observations where the amorphous phase prevailed and a relatively low crystalline phase (tiny crystals) was observed. these results are also complementary with the composition of volcanic glass observed by edx measurement. 3.7. thermal examinations the thermogravimetric analysis (tga) and the differential thermal analysis (dta) of the analyzed raw volcanic rock indicates weight loss in three temperature intervals (fig. 9). the first temperature interval is between 20 and 215 ºc resulting with a subtle weight loss of 0.68% attributed to the loss of adsorbed water on the perlite surface. the major mass loss of 2.69% occurs in the temperature interval from 215–477 ºc and is a consequence of the hydroxyl groups release. bearing in mind the absence of organic matter due to the lack of determined carbon (according to the chemical analysis), we suggest that the remaining chemically bonded water (0.43%) (roulia et al., 2006; celik et al., 2013), is released in the temperature interval from 477–826 ºc. 3.8. solid state (cp-mas) 1h nmr spectroscopy the 1h cp-mas nmr spectra of the crude perlite (fig. 10) consists of two peaks. the first maximum around 0.3 ppm is very intensive and relatively narrow, whereas the second weak and broad peak evolves around 3.5 ppm. this second peak exhibits a broad appearance due to the overlapping of the signals from the homonuclear dipolar interactions and chemical shift distribution caused by sample disorder, reflecting the predominant amorphous nature of the analyzed specimen. the obtained spectrum compares well with previous published solid state 1h nmr spectra of perlite from other regions (zujovic et al., 2018). however, the lower or more narrow but intensive signal at 0.3 ppm serves as an indicator for the crystallinity phase of the sample that was also depicted from the collected xrpd spectrum (see fig. 3, top). 4. conclusions the first full characterization of the unexpanded and expanded perlite from mariovo allows the following conclusions to be drawn: i) chemical analysis of the volcanic rock suggests that the raw material represents acidic volcanic rock, with a high percenta ge of sio2 (72.48%), whereas the presence of al2o3 is 13.52%. the percentage of alkali metal oxides, k2o and na2o is 4.21% and 3.56% respectively. ii) results from the xrd examination suggest a high percentage of amorphous phase, with the minimal presence of crystalline forms. the crystalline phase is mainly composed of feldspars, and sio2 polymorphs (quartz and cristobalite). iii) the results from the optical microscopy confirm the results from the xrd analysis; the volcanic rock is composed of an isotropic amorphous glassy mass with the presence of finegrained particles-microlite. iv) the sem results are commensurate with the findings delivered by optical microscopy. sem photomicrographs undoubtedly report on the fluid character of the glassy mass and the compact glass mass of the perlite with the presence of tiny crystals and pores. on the other hand, the sem results from the expanded perlite revealed the presence of open pores (small channels which form a dense network) and some isolated holes and cells in its microstructure. the simultaneous presence of these open pores and isolated holes delivers extremely high transpiring power (absorb water and then release the water in the form of vapour) and high strength, respectively. the difference is pronounced by the fact that the transpiring characteristic plays a pivotal role in the thermal insulation property of the material, whereas high strength is needed for structural lightweight concrete. v) total mass loss of 3.80 wt.% observed during the tg treatment was correlated with trapped water escaping from the volcanic rock. vi) the ir spectrum provides valuable information regarding the presence of absorbed water in perlite (1644 cm-1 and 3650 cm-1 bands) that was essentially excreted during the expansion process (the corresponding bands disappeared). due to the low proportion of a crystalline phase fortified by the abovementioned results, it can be concluded that analyzed volcanic rock (perlite), represents valuable starting material for production of high quality expanded perlite. as a result of the high percentage of alkali metal oxides, the high percentage of sio2, the volcanic glass (perlite) can be utilized as a raw material for the production of container glass. the high percentage of the glassy phase, high percentage of sio2 and alkali metal oxides makes perlite from mariovo an attractive material for the production of acid resistant glazing materials. references ahmadia, p.f., ardeshira, a., ramezanianpourb, a.m. & bayata, h. (2018): characteristics of heat insulating clay bricks made from zeolite, waste steel slag and expanded perlite.– ceram. int., 44, 7588–7598. doi: 10.1016/j.ceramint.2018.01.175 figure 10. solid state 1h nmr spectrum of the native perlite (volcanic glass). g eologia c roatica reka et al.: chemical, mineralogical and structural features of native and expanded perlite from macedonia 221 breese, r.o.y. (1984): rhyolite domes and flows at no aqua peaks.– proceeding of the 35th annual field conference, socorro, new mexico geological society, 373–374. burriesci, n., arcoraci, c., antonucci, pl. & polizzotti, g. (1985): physico-chemical characterization of perlite of various origins.– mater. lett., 3, 103–110. doi: 10.1016/0167-577x(85)90008-4 cekova, b., pavlovski, b., spasev, d. & reka, a. (2013): structural examinations of natural raw materials pumice and trepel from republic of macedonia.– proceedings of the xv balkan mineral processing congress, sozopol, bulgaria, 73–75. celik, a.g., kilic, a.m. & cakal, g.o. (2013): expanded perlite aggregate characterization for use as a lightweight construction raw material.– physicochem. probl. miner. process., 49, 689−700. doi: 10.5277/ppmp130227 evans, a.m. (1993): perlite.– ore geology and industrial minerals, 3rd edition, oxford, boston, blackwell science, 295–296. harben, p.w. & kuzvart, m. (1997): industrial minerals – a global geology.– industrial minerals information, london, metals bulletin, 280–288. jovanovski, g., boev, b. & makreski, p. (2012): minerals from the republic of macedonia with an introduction to mineralogy, macedonian academy of sciences and arts, skopje, 1–652. kaufhold, s., reese, a., schwiebacher, w., dohrmann, r., grathoff, g.h., warr, l.n., halisch, m., müller, c., schwarz-schampera, u. & ufer., k. (2014): porosity and distribution of water in perlite from the island of milos, greece.– springerplus 3, 598 (pages 10). doi: 10.1186/2193-18013-598 kirschenbaum, h. (1983): the classical chemical analysis of silicate rocks – the old and the new.– geol. survey bull., 1547, 1–55. doi: 10.3133/b1547 kogel, j.e., trivedi, n.c., baker, j.m. & kurkowski, s.t. (2006): industrial minerals & rocks, 7th edition. society for mining, metallurgy and exploration, inc., 865 p. kongkachuichay, p. & lohsoontorn, p. (2006): phase diagram of zeolite synthesized from perlite and rice husk ash.– scienceasia, 32, 13–16. doi: 10.2306/ scienceasia1513-1874.2006.32.013 koukouzas, n. (1998): volcanic glass (perlite) of kimolos island, greece: mineral chemistry and structure.– proceedings of the 8th international, patras, bulletin of the geological society of greece, xxxii/3, 313–332. li, h. & tomozawa, m. (1994): mechanical strength increase of abraded silica glass by high pressure water vapor treatment.– j. non-cryst. solids, 168, 287–292. doi: 10.1016/0022-3093(94)90341-7 makreski, p. & jovanovski, g. (2003): minerals from macedonia. ix. distinction between some rhombohedral carbonates by ftir spectroscopy. – bull. chem. technol. macedonia, 22, 25–32. makreski, p., jovanovski, g. & kaitner, b. (2009): minerals from macedonia. xxiv. spectra-structure characterization of tectosilicates.– j. mol. struct., 924–926, 413–419. doi: 10.1016/j.molstruc.2009.01.001 pavlovski, b., jančev, s., petreski, l., reka, a., bogoevski, s. & boškovski, b. (2011): trepel – a peculiar sedimentary rock of biogenetic origin from the suvodol village, bitola, r. macedonia.– geologica macedonica, 25, 67–72. reka, a.a., anovski, t., bogoevski, s., pavlovski, b. & boškovski, b. (2014): physical-chemical and mineralogical-petrographic examinations of diatomite from deposit near village of rožden, republic of macedonia.– geologica macedonica, 28, 121–126. reka, a.a., pavlovski, b. & makreski, p. (2017): new optimized method for low-temperature hydrothermal production of porous ceramics using diatomaceous earth.– ceram. int., 43, 12572–12578. doi: 10.1016/j.ceramint.2017.06.132 rodriguez, j., soria, f., geronazzo, h. & destefanis, h. (2016): modification and characterization of natural aluminosilicates, expanded perlite, and its application to immobilise α-amylase from a. oryzae.– j. mol. catal. b, 133, s259– s270. doi: 10.1016/j.molcatb.2017.01.012 roulia, m., chassapis, k., kapoutsis, j.a., kamitsos, e.i. & savvidis, t. (2006): influence of thermal treatment on the water release and the glassy structure of perlite.– j. mater. sci., 41, 5870–5881. doi: 10.1007/s10853-006-0325-z sodeyama, k. & sakka, y. (2007): preparation and utilization of fine expanded perlite.– key. eng. mat., 280–283, 701–706. doi: 10.4028/www.scientific.net/ kem.280-283.701 sodeyama, k., sakka, y., kamino, y. & seki, h. (1999): preparation of fine expanded perlite.– j. mater. sci., 34, 2461–2468. šontevska, v., jovanovski, g. & makreski, p. (2007): minerals from macedonia. part xix. vibrational spectra of some sheet silicate minerals.– j. mol. struct., 834–836, 318–327. doi: 10.1016/j.molstruc.2006.10.026 spasovski, o. & spasovski, d. (2012): the potential of the nonmetallic mineral resources in the republic of macedonia.– geologica macedonica, 26, 91–94. varga, p., lexa, j., uhlík, p. & rajnoha, m. (2015): characterization of perlites from jastrabá and lehôtka pod brehmi deposits.– geol. geophys. environ., 41, 146–146. doi: 10.7494/geol.2015.41.1.146 varuzhanyan, av.a., varuzhanyan, ar.a. & varuzhanyan, h.a. (2006): a mechanism of perlite expansion.– inorg. mater., 42, 1039–1045. doi: 10.1134/s0020168506090202 vijayaraghavan, k. & raja, f.d. (2014): experimental characterisation and evaluation of perlite as a sorbent for heavy metal ions in single and quaternary solutions.– j. water process eng., 4, 179–184. doi: 10.1016/j.jwpe.2014.10.001 zafirovski, s., jasmakovski, b., zlatanovic, v. & pavlovski, b. (1987): use of perlites in the ceramic industry.– 2nd int. conf. of natural glasses, prague, 169–175. zujovic, z., wheelwright, w.v.k, kilmartina, p.a., hanna, j.v. & cooney, r.p. (2018): structural investigations of perlite and expanded perlite using 1h, 27al and 29si solid-state nmr.– ceram. int., 44, 2952–2958. doi: 10.1016/j.ceramint.2017.11.047 2021 | 74/2 | 287–303 | 11 figs. | 5 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction manganese deposits in turkey are divided into four main groups by noting sources, tectonic environments, and structural features (öztürk, 1993). these are; 1. hydrothermal and hydrogenous manganese deposits within radiolarite cherts, 2. diagenetic deposits related to black shales within lower cretaceous carbonates, 3. hydrothermal deposits within volcano-sedimentary and 4. sedimentary-derived deposits within oligocene sediments. many manganese formations are observed along a line from west to east in yozgat province. most of these are emplaced within ophiolitic units widely observed in the region and are manganese-ferromanganese deposits interlayered with radiolarites. though some deposits were determined to have very high grades (up to 69.91%), they remain short-term operations due to low reserves. while si values reach up to 40% in some regions, the fe content values reach up to 29% (öksüz 2011a,b; öksüz & okuyucu, 2014; öksüz, 2018; öksüz et al., 2021). the geological, mineralogical, and geochemical assessments of these formations have been the topic of many studies (öksüz, 2011a,b; öksüz & okuyucu, 2014; öksüz, 2018; öksüz et al., 2021). in those studies, it was determined that yozgat manganese ­deposits­have­three­different­origins­of­hydrothermal,­hydro­ genous, and detrital sources. the topic of the study is the ferromanganese mineralization observed­in­the­eğerci­region,­which­was­observed­to­be­different from other mineralization in the yozgat region. this ferromanganese deposit in the region was selected as the research topic as it has not appeared in any previous studies. the basic aims of the­study­were­to­define­the­geology­of­the­region,­the­ore­para­ genesis of ferromanganese deposits from the central anatolian province, yozgat-aşağı eğerci village-turkey: geochemical properties and fluid inclusions nursel öksüz1,* and sümeyra kaya2 1 bozok university, faculty of engineering & architecture, department of geological engineering, 66100 yozgat, turkey; (corresponding author: nursel.oksuz@gmail.com) 2 bozok university, graduate education institute, 66100 yozgat, turkey doi: 10.4154/gc.2021.20 abstract eğerci village is located 16 km southwest of yerköy (yozgat) area which has a ferromanganese deposit that formed at the contact between basalt and limestone and shows that a banded stockwork structure occurs occasionally within the limestone. the mineralization consists of pyrolusite, goethite, and ramsdellite, together with a lesser quantity of magnetite. gangue minerals are determined as calcite and quartz. ree data from the mineral samples demonstrate a range from 2.70 63.70 ppm and the average value is 28.00. these results permit a comparison to be made with mineralization in hydrothermal deposits. moreover, mineral samples show a positive eu anomaly 0.88-48.10 ppm (ave. 9.94 ppm). the ce anomaly values vary between 0.02 and 0.88 ppm (ave. 0.58 ppm). it is possible that the mineralization may be affected by the mixing of seawater and hydrothermal fluids. the value of the positive eu anomaly is evidence of modern oceanic hydrothermal manganese deposits. insight of previous fluid inclusion, studies can be easily inferred that mineralization can occur at three different stages. the temperature of the first stage ranged from 338 oc to 428 oc and other stages vary from 269 oc 317 oc and 143 oc 236 oc, respectively. as a comparison, calculated salinity is higher in type i fluid inclusions (1.9-14.7 wt.% nacl equiv.) than type ii and iii fluid inclusions (1.9-5.1 wt.%nacl equiv.) it is possible that the mineralization was formed by the mixing of magmatic and meteoric waters. genesis,­wall­rocks,­the­sources­of­different­hydrothermal­fluids­ in­the­mineralization­with­ore­ree­geochemistry,­and­fluid­inclusion studies and to determine a mineralization model for ore deposits in the region. 2. geological setting 2.1. regional geology the manganese mineralization which forms the topic of the study is­observed­in­aşağı­eğerci­village­located­16­km­southwest­of­ yerköy (yozgat) county and is situated within one of the most important massifs in turkey of the central anatolian massif. the oldest­unit­outcropping­in­the­region­is­the­paleozoic­bozçaldağ­ formation (fig. 1). the unit named by seymen (1982) comprises grey coloured, mostly coarse calcite crystal-rich, moderately-thick bedded marbles, and massive marbles. the massive marbles­are­observed­in­a­very­small­area­south­of­hacılı­village­ in the study area and are cut by an upper cretaceous central anatolian­granite­(akçay­et­al.,­2007).­the­eocene­boğazköy­ formation (özcan et al., 1980) transgressively overlies intrusives in some regions and older units above an angular unconformity in other regions in the study area and close surroundings. the unit has volcanic interlayers and comprises sandstone, siltstone, some pebblestone, mudstone, and limestone. this formation is divided into three members of the ‘limestone member’ comprising sandy-silty limestone and massive limestone containing­nummulites,­corals­and­gastropod­fossils,­the­‘alimpınar­volcanic member’ comprising basalt and basaltic pyroclastic rocks, and­the­‘dacite­member’­comprising­dominantly­dacitic­tuffs­with­ occasional dacitic and rhyolitic rocks (özcan et al., 1980). the dacite member is not observed in the study area. these three article history: manuscript received may 20, 2021 revised manuscript accepted september 10, 2021 available online october 27, 2021 keywords: ferromanganese, rare earth elements, hydrothermal, fluid inclusions, yozgat (turkey) g eo lo gi a c ro at ic a 288 geologia croatica 74/3 members­identified­in­the­formation­have­both­lateral­and­vertical transitions with each other. additionally, the basal structures observed­in­the­alimpınar­volcanic­member­indicate­submarine­ volcanism. the unit is generally observed in the north-northwest and­southeast­regions­around­aşağı­eğerci­village.­the­oligocene­i̇ncik­formation­(oktay,­1981),­is­distinguished­by­dominant pebblestone, sandstone, and mudstone lithologies and formed in a terrestrial environment, while middle miocene-pliocene­lacustrine­and­terrestrial­fluvial­sediments­unconformably­ overlie all units. the youngest unit in the region is the quaternary alluvium (ketin, 1955; akçay et al., 2007). in­the­study­area,­the­effects­are­observed­of­the­laramian­ stage of alpine orogenesis on the intense deformation of central anatolia and the taurus (ketin, 1966). magmatism covering large areas of the region occurred as plutonic activity within crystalline massifs, and submarine volcanism in the upper cretaceous and middle eocene periods. middle eocene units represent rocks developed in shallow marine and volcanic facies. in the lower-middle eocene period, the sea level was higher than in the cretaceous period. towards the end of the middle eocene, the sea gradually began to retreat, lagoons formed, and gypsum and clayey marls formed toward the end of the middle eocene. at the end of the middle eocene, the sea regressed further and at the same time uplift and erosion occurred, with red conglomeritic units forming in the oligocene. during the oligocene, the sea regressed further and lagoons formed. at the end of the oligocene, occasional fresh and saltwater lakes remained while the sea was fully regressed (ketin, 1955). volcanic activity in younger cycles was not observed in the study area (ketin, 1955). figure 1. location and geology map of the study area (modified by akcay et al. 2007). g eologia c roatica 289öksüz and kaya: genesis of ferromanganese deposits from the central anatolian province, yozgat-aşağı eğerci village-turkey ... 3. sampling and analytical methods a total of 40 ore samples were taken systematically from the ferromanganese mineralization observed in the study area. these samples were separated for geochemical analysis, polished sections,­and­fluid­inclusion­studies.­sample­powders­under­200­ mesh were analyzed at the general directorate of mineral research and exploration (mta) in turkey. major oxide and trace element contents were determined with icp-es and ree’s were analyzed with the icp-ms method. results of the analyses are given in tables 1 to 3. polished sections were prepared from 15 samples by the same unit. the polished samples were investigated­with­a­reflected­light­leica­microscope­in­bozok­university laboratory. for accuracy of ore paragenesis, 15 samples had xrd analysis performed in the bozok university science and technology application and research centre (biltem). for­fluid­inclusion­analysis,­quartz­and­calcite­samples­observed as veins were examined in mineralized samples from the study­area.­a­total­of­4­samples­had­fluid­inclusion­studies­performed. measurements were performed microthermometrically on double-sided polished sections, using a linkam thmg-600 heating and cooling stage mounted on an olympus bx51 microscope­in­the­recep­tayyip­erdoğan­university,­department­of­ geological­engineering.­the­equipment­was­suitable­for­microthermometric measurements from -196 to 600 °c. the linksys-32 dv program was used for measurements with 0.1 °c sensitivity and repeated measurements were shown to have an accuracy of ±0.2 °c for freezing and ±1 °c for heating experiments. 4. geology of mineralization the­boğazköy­formation­observed­in­the­region­comprises­volcanic interlayers, sandstone, siltstone, and lesser amounts of pebble stone, mudstone, and limestone (özcan et al., 1980). at the base­of­the­unit,­poorly­defined­beds­of­­grey­and­occasionally­ red coloured pebblestone and sandstone occur. above these, there are coal interlayers, light grey in colour, parallel bedded, graded, well-consolidated sandstones and siltstones, and very fine­grained­pebblestones.­the­eocene­boğazköy­formation­is­ divided­into­three­members;­the­‘limestone­member’,­‘alimpınar­ volcanic member’ and ‘dacite member’. the ‘limestone member’ is commonly observed in the study area and comprises coral, gastropod, and lamellibranchs, grey, moderately-thickly bedded, sandy-silty limestone, and massive limestones (fig. 2a-c). the unit is widely observed in the region and contains banded and stockwork ferromanganese formations in the study area (fig. 2c, d-f). the­alimpınar­volcanic­member­comprises­basalt­and­pyroclastics of basaltic composition. the unit with widespread outcrops in the study area has a lateral transition to the limestone member. basalts with basal structures indicating submarine volcanism are a purple-black colour, with large glassy minerals, abundant fractures, and joints (fig. 2c). pyroclastics are lightly coloured, with uneven erosion surfaces and glass fragments (akçay et al., 2007) (fig. 2g). the unit has a broad distribution in the study area. manganese mineralization is observed as bands and occasional stockwork at the contact with limestone and within the limestones (fig. 2, d-f). 4.1. ore petrography polished sections of the mineralized samples were investigated with­a­reflected­light­microscope.­additionally,­xrd­analysis­ ta bl e 1. m aj or o xi de c on te nt s ( % ) i n th e or e sa m pl es . sa m pl es % e1 e3 e6 e7 e9 e10 e13 e14 e15 e16 e17 e18 e19 e20 e21 e22 e23 e24 e25 e26 m in . m ax . av e. si o 2 0. 40 13 .9 0 2. 30 8. 80 10 .4 0 61 .0 0 35 .4 0 38 .5 0 0. 50 12 .0 0 2. 50 9. 10 11 .3 0 62 .0 0 33 .2 0 37 .0 0 1. 50 8. 10 11 .6 0 3. 90 0. 40 62 .0 0 18 .1 7 a l 2o 3 0. 10 4. 00 0. 60 0. 70 5. 50 0. 10 0. 10 0. 10 0. 20 3. 30 0. 40 0. 50 5. 40 0. 10 0. 20 0. 10 0. 30 0. 40 0. 10 0. 50 0. 10 5. 50 1. 14 ca o 50 .2 0 11 .7 0 21 .1 0 4. 80 26 .9 0 2. 50 15 .4 0 0. 40 48 .1 0 12 .5 0 20 .0 0 5. 10 27 .8 0 3. 50 16 .2 0 0. 50 10 .0 0 19 .2 0 3. 80 15 .4 0 0. 40 50 .2 0 15 .7 6 fe 2o 3 0. 1 2. 40 0. 40 42 .1 0 2. 40 14 .2 0 21 .5 0 33 .6 0 0. 20 3. 40 0. 30 43 .1 0 2. 50 14 .8 0 21 .0 0 30 .5 0 38 .5 0 2. 20 0. 50 39 .9 0 0. 20 43 .1 0 16 .5 0 k 2 o 0. 10 1. 90 0. 10 0. 80 1. 70 0. 10 0. 10 0. 10 0. 10 1. 50 0. 20 0. 80 1. 50 1. 70 0. 10 1. 80 0. 30 0. 60 0. 10 0. 10 0. 10 1. 90 0. 69 m go 0. 30 0. 80 0. 40 1. 40 1. 00 0. 30 0. 30 0. 40 0. 30 0. 70 0. 20 1. 20 0. 90 0. 20 0. 40 0. 30 0. 20 0. 10 0. 80 0. 60 0. 10 1. 40 0. 54 m no 9. 20 48 .4 0 52 .2 0 26 .9 0 19 .4 0 14 .9 0 11 .3 0 18 .0 0 10 .1 0 45 .3 0 50 .9 0 27 .3 0 20 .3 0 15 .1 0 12 .8 0 19 .2 0 21 .5 0 47 .3 0 55 .2 0 28 .0 0 9. 20 55 .2 0 27 .6 7 n a 2 o 0. 10 0. 10 0. 10 0. 10 0. 40 0. 10 0. 10 0. 10 0. 10 0. 10 0. 20 0. 30 0. 10 0. 20 0. 10 0. 10 0. 20 0. 10 0. 10 0. 30 0. 10 0. 40 0. 15 p 2 o 5 0. 10 0. 20 0. 40 0. 10 0. 30 0. 10 0. 10 0. 10 0. 10 0. 30 0. 20 0. 40 0. 30 0. 10 0. 20 0. 40 0. 20 0. 10 0. 10 0. 20 0. 10 0. 40 0. 20 ti o 2 0. 10 0. 20 0. 10 0. 10 0. 30 0. 10 0. 10 0. 10 0. 20 0. 10 0. 30 0. 10 0. 10 0. 20 0. 30 0. 20 0. 10 0. 10 0. 20 0. 30 0. 10 0. 30 0. 17 lo i 39 .0 0 16 .5 0 21 .9 0 13 .9 0 23 .5 5 6. 40 16 .0 0 0. 40 39 .0 0 19 .9 0 24 .5 0 11 .7 0 28 .7 0 1. 70 16 .4 0 9. 20 24 .8 0 20 .0 0 26 .4 0 9. 40 0. 40 39 .0 0 18 .4 7 m n/ fe 10 1. 86 22 .3 1 14 4. 39 0. 71 8. 94 1. 16 0. 58 0. 59 55 .8 6 14 .7 4 18 7. 71 0. 70 8. 98 1. 13 0. 67 0. 70 0. 62 23 .7 9 12 2. 14 0. 78 0. 58 18 7. 71 34 .9 2 a l 2o 3/ ti o 2 1. 00 20 .0 0 6. 00 7. 00 18 .3 3 1. 00 1. 00 1. 00 1. 00 33 .0 0 1. 33 5. 00 54 .0 0 0. 50 0. 67 0. 50 3. 00 4. 00 0. 50 1. 67 0. 50 54 .0 0 8. 03 g eo lo gi a c ro at ic a 290 geologia croatica 74/3 was performed to support the mineral paragenesis (fig. 3). accordingly, the main minerals in the ore paragenesis were pyrolusite, goethite, and ramsdellite. lesser amounts of magnetite were­observed.­the­gangue­minerals­comprise­calcite­and­quartz.­ pyrolusite is the most abundant manganese oxide mineral in manganese­deposits.­there­are­three­different­polymorphs­of­ mno2. the most stable and abundant of these is pyrolusite, which is a mineral that may form in both supergene and low-temperature hydrothermal environments and does not infer meaning in terms of origin (nicholson, 1992). apart from this, other manganese minerals including ramsdellite and manganite occur in the form of replacements. pyrolusite formation is typical with weathering developing in terrestrial environments. in this type of mineralization, pyrolusite may contain simple remnant materials from the environment during transport and pyrolusite precipitation generally occurs in carbonate rocks including limestone or dolomite (ramdohr, 1980). in environments with a high oxidation potential, pyrolusite may be independent of ph (krauskopf, 1989). it displays a cream and yellow colour under­the­first­nicol,­while­there­is­cream,­yellow,­bluish­grey­strong­ figure 2. a, b. limestone member: fossiliferous limestone comprising sandy-silty limestone and massive limestones, c. black basalt with abundant fractures and joints showing basal structures indicating submarine volcanism. mn: manganese, bs: basalt; pr: pyroclastics, kct: limestone, d, e, f. banded and occasionally stockwork mineralization at basalt-limestone contacts and within the limestone. g. light-coloured pyroclastics with undulating erosion surface. figure 3. x-ray diffractogram for the mineralized samples. g eologia c roatica 291öksüz and kaya: genesis of ferromanganese deposits from the central anatolian province, yozgat-aşağı eğerci village-turkey ... anisotropy under the second nicol (fig. 4a, b). there are three different­pyrolusite­types­in­the­study­area­(fig.­4c).­one­of­these­ is­vein­fill­with­small­grain­size­(fig.­4d),­while­the­other­has­ larger grains in the form of foliation (fig. 4c, e, f). additionally, pyrolusites were observed in the form of replacements with ramsdellite (fig. 4e-h). ramsdellite is one of the naturally occurring manganese oxide polymorphs. due its similarities with pyrolusite, it is very difficult­to­make­a­direct­comparison.­though­pyrolusite­is­more­ commonly observed, ramsdellite may be found in abundant amounts­in­manganese­rich­environments­exposed­to­aqueous­ alteration at low temperatures (ostwald et al., 1984). if the two minerals form together, pyrolusite is notable for its higher sheen. both minerals are included in the paragenesis of the other, and ramsdellite converts to pyrolusite when heated above 300 oc (ramdohr, 1980). this type of transformation is in the form figure 4. polished section photographs of mineralized samples. a. cream and yellow goethite replacing pyrolusite and brecciated light and dark grey colour goethite (i nicol), b. bluey grey, strongly anisotropic pyrolusite and orange-brown goethite with strong internal reflection (ii nicol). c. foliation in large-grained (py-i) and fine-grained pyrolusite (py-ii). d. fine-grained, vein-fill pyrolusite (i nicol), light and dark grey goethite with occasional oolite-like texture (i nicol). e. cream, bright yellow ramsdellite and pyrolusite were observed replacing ramsdellite (i nicol). f. same photograph (ii nicol). py: pyrolusite, gth: goethite, r: ramsdellite. g eo lo gi a c ro at ic a 292 geologia croatica 74/3 ta bl e 2. tr ac e el em en ts c on te nt s ( pp m ) i n th e or e sa m pl es . pp m e1 e3 e6 e7 e9 e10 e13 e14 e15 e16 e17 e18 e19 e20 e21 e22 e23 e24 e25 e26 m in . m ax . av e. a s 15 .2 12 0. 0 74 .2 41 2. 0 52 .6 19 5. 3 20 6. 0 26 9. 5 16 .3 12 5. 0 75 .5 39 8. 9 55 .4 20 0. 3 20 4. 0 28 0. 2 18 .3 11 5. 8 78 .1 15 3. 3 15 .2 41 2. 0 15 3. 3 be 0. 2 1. 7 1. 0 1. 8 0. 8 0. 1 2. 1 0. 3 0. 2 1. 6 0. 9 1. 8 0. 7 0. 3 1. 9 0. 1 1. 7 2. 3 0. 1 1. 0 0. 1 2. 3 1. 0 bi 1. 3 18 .9 18 .1 10 .8 3. 3 2. 8 3. 4 8. 8 1. 2 18 .4 17 .8 10 .4 3. 5 2. 5 3. 4 8. 9 1. 5 17 .5 9. 2 8. 5 1. 2 18 .9 8. 5 cd <0 .1 1. 2 1. 1 17 .1 0. 2 5. 7 7. 1 13 .0 0. 9 1. 5 1. 2 15 .2 0. 5 5. 8 7. 5 12 .4 4. 2 1. 2 1. 4 5. 4 0. 2 17 .1 5. 4 co 4. 5 45 .6 37 .1 38 .3 19 .7 28 .5 19 .9 22 .3 4. 2 43 .2 36 .8 35 .2 18 .9 29 .1 18 .4 24 .1 4. 6 44 .9 36 .5 26 .9 4. 2 45 .6 26 .9 cu 16 .0 22 9. 6 22 4. 9 10 8. 6 55 .1 11 .4 4. 1 <0 .1 15 .8 22 32 .1 22 7. 2 10 6. 6 54 .9 10 .8 4. 9 0. 2 14 .9 20 5. 8 19 0. 0 20 6. 3 0. 2 22 32 .1 20 6. 3 g a 2. 4 12 .7 11 .2 10 .6 9. 8 3. 6 7. 6 4. 6 2. 3 11 .9 10 .9 10 .3 9. 7 3. 3 7. 5 4. 2 2. 1 11 .8 10 .9 7. 8 2. 1 12 .7 7. 8 g e 0. 3 1. 2 0. 9 5. 4 0. 7 2. 0 2. 6 4. 2 0. 2 1. 3 0. 8 5. 2 0. 7 1. 9 2. 4 4. 3 0. 3 1. 3 0. 7 1. 9 0. 2 5. 4 1. 9 h f <0 .1 1. 5 0. 4 0. 2 2. 6 <0 .1 0. 1 0. 1 0. 1 1. 4 0. 3 0. 2 2. 4 0. 1 0. 1 1. 2 0. 9 2. 2 0. 4 0. 8 0. 1 2. 6 0. 8 in <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 m o 3. 0 38 .5 23 .1 33 .4 20 .5 18 .2 15 .6 21 .7 2. 9 37 .5 22 .9 34 .2 20 .2 17 .4 15 .4 19 .8 20 .5 31 .2 15 .2 21 .6 2. 9 38 .5 21 .6 n i 23 .7 91 .9 25 2. 1 10 4. 4 61 .6 91 .2 25 .1 16 .1 23 .4 89 .2 24 5. 2 10 3. 2 30 .8 90 .8 89 .5 25 .3 17 .5 21 .5 15 .8 74 .6 15 .8 25 2. 1 74 .6 sb 0. 7 3. 3 3. 1 7. 9 1. 5 3. 6 1. 6 3. 2 0. 6 3. 2 3. 1 8. 1 1. 4 3. 3 1. 4 3. 1 0. 7 3. 6 5. 4 3. 1 0. 6 8. 1 3. 1 tl 0. 4 0. 3 9. 9 0. 3 0. 2 <0 .1 <0 .1 <0 .1 0. 4 0. 5 8. 9 0. 2 0. 1 0. 3 0. 1 0. 4 0. 2 0. 1 0. 1 1. 4 0. 1 9. 9 1. 4 ba 14 8. 4 35 50 .1 47 50 .0 38 25 .0 93 0. 2 30 33 .3 62 19 .1 54 06 .7 15 0. 2 36 70 .0 48 20 .0 38 32 .0 89 0. 0 30 27 .0 63 15 .0 53 21 .0 29 80 .0 45 20 .0 39 25 .0 36 87 .9 14 8. 4 63 15 .0 36 87 .9 cr 7. 8 40 .9 23 .4 14 .0 53 .2 11 .5 7. 0 10 .5 7. 6 35 .2 22 .1 15 .1 52 .1 10 .9 6. 9 10 .3 8. 1 41 .2 21 .5 21 .6 6. 9 53 .2 21 .6 cs 0. 5 0. 9 0. 2 1. 6 1. 6 0. 1 0. 2 0. 1 0. 4 0. 8 0. 2 1. 5 1. 6 0. 2 0. 1 1. 4 0. 4 0. 8 1. 2 0. 7 0. 1 1. 6 0. 7 n b 0. 3 2. 6 0. 8 0. 4 5. 0 0. 1 0. 2 0. 2 0. 2 2. 4 0. 7 0. 4 4. 8 0. 1 0. 3 2. 1 3. 2 0. 1 0. 2 1. 3 0. 1 5. 0 1. 3 pb 10 .6 64 .8 39 .9 49 .4 39 .9 23 .5 24 .1 40 .7 10 .5 60 .2 38 .1 42 .5 37 .1 22 .9 24 .5 39 .7 9. 9 63 .9 42 .6 36 .0 9. 9 64 .8 36 .0 rb 10 .5 58 .0 23 .0 41 .5 54 .3 12 .3 7. 2 8. 8 10 .4 54 .5 23 .5 40 .9 52 .8 11 .9 7. 5 8. 6 9. 8 55 .2 25 .4 27 .2 7. 2 58 .0 27 .2 sr 19 6. 4 82 3. 0 83 4. 5 80 6. 3 32 1. 0 42 4. 0 57 8. 0 49 4. 5 19 4. 5 82 0. 8 85 0. 2 80 4. 1 32 5. 4 42 5. 3 58 0. 5 47 0. 8 20 5. 0 56 2. 2 49 2. 5 53 7. 3 19 4. 5 85 0. 2 53 7. 3 ta 0. 1 0. 4 0. 2 0. 3 0. 6 0. 6 0. 4 0. 4 0. 1 0. 3 0. 2 0. 4 0. 5 0. 6 0. 4 0. 1 0. 2 0. 3 0. 4 0. 3 0. 1 0. 6 0. 3 zr 3. 3 73 .6 25 .7 12 .2 13 4. 0 1. 2 4. 6 3. 6 3. 2 74 .1 24 .2 13 .5 12 0. 4 1. 5 5. 1 3. 7 3. 2 70 .5 24 .8 31 .7 1. 2 13 4. 0 31 .7 h f 0. 1 1. 5 0. 4 0. 2 2. 8 0. 1 0. 1 0. 1 1. 5 0. 3 0. 1 0. 2 2. 5 1. 2 0. 1 0. 2 2. 1 1. 2 0. 1 0. 8 0. 1 2. 8 0. 8 sc 2. 1 5. 6 2. 6 2. 1 7. 3 1. 6 1. 7 1. 8 1. 9 5. 2 2. 5 2. 2 7. 4 1. 4 1. 2 1. 8 2. 3 5. 1 2. 8 3. 2 1. 2 7. 4 3. 2 th 0. 7 2. 2 0. 9 0. 8 3. 9 0. 1 0. 3 0. 3 0. 6 2. 1 0. 9 3. 7 0. 1 0. 2 0. 6 2. 7 0. 3 0. 1 0. 4 1. 1 0. 1 3. 9 1. 1 u 0. 9 7. 9 3. 0 2. 6 3. 8 2. 4 4. 6 9. 8 0. 8 7. 5 2. 9 2. 5 3. 7 2. 2 4. 4 9. 7 0. 9 7. 4 2. 9 4. 2 0. 8 9. 8 4. 2 v 30 .9 23 8. 5 16 5. 0 28 1. 8 12 1. 3 11 6. 4 31 .7 75 .4 29 .8 23 4. 2 17 0. 8 28 5. 1 11 9. 8 11 5. 4 30 .8 74 .2 12 0. 2 25 0. 7 28 .9 13 2. 7 28 .9 28 5. 1 13 2. 7 co /n i 0. 1 0. 5 0. 3 0. 2 0. 7 0. 1 0. 1 0. 1 0. 1 0. 5 0. 3 0. 2 0. 6 0. 1 0. 3 1. 2 1. 4 0. 0 0. 1 0. 4 0. 0 1. 4 0. 4 v/ (v +n i) 23 .1 15 8. 5 83 .5 64 .1 19 5. 6 19 .2 39 .1 32 .4 30 .4 16 0. 6 86 .4 74 .3 18 5. 6 21 .0 20 .4 3. 2 2. 3 35 95 .5 34 7. 2 81 .0 2. 3 35 95 .5 26 1. 2 sr /b a 1. 3 0. 2 0. 2 0. 2 0. 3 0. 1 0. 1 0. 1 1. 3 0. 2 0. 2 0. 2 0. 4 0. 1 0. 1 0. 1 0. 1 0. 1 0. 1 0. 1 0. 1 1. 3 0. 3 g eologia c roatica 293öksüz and kaya: genesis of ferromanganese deposits from the central anatolian province, yozgat-aşağı eğerci village-turkey ... of nested or small pyrolusites observed surrounding ramsdellite in­the­study­area­(fig.­4e­h).­ramsdellite­identified­with­xrd­is­ differentiated­from­pyrolusite­by­its­greenish­grey­anisotropy­ colo ur especially (see fig. 3; fig. 4f, h; fig. 5b). the other mineral commonly observed in mineralization in the study area is goethite. goethite observed on both xrd and ore­microscopy­shows­the­presence­of­several­different­stages­ within the mineralization (fig. 4a b; fig. 5c-h). goethite is observed­with­different­shades­of­grey­under­the­first­nicol­and­has­ typical­yellow,­orange,­and­red­internal­reflection­under­the­se­ cond nicol (fig. 5d, f, h). in some samples, oolitic textures in goethite are very pronounced (fig. 5g, h). though these textures are actually sedimentation textures, similar shapes may form in mineralization developing from solutions and melts in some circumstances. though the resemblance of these textures to bacteria was discussed­at­first,­later­studies­state­that­they­represent­a­hydrofigure 5. polished section photographs of mineralized samples. a. ramsdellite in the form of veins within goethite (i nicol), b. ramsdellite with strong greenish anisotropy (ii nicol). c. colloid texture, greyish colour goethite (i nicol). d. colloid texture goethite with clear orange internal reflection (ii nicol). e. colloid texture, greyish colour goethite (i nicol). f. colloid texture goethite with clear orange internal reflection (ii nicol). g. light and dark grey goethite with oolitic texture (i nicol). h. goethite with oolitic texture showing red and orange internal reflection (ii nicol). py: pyrolusite, gth: goethite, r: ramsdellite. g eo lo gi a c ro at ic a 294 geologia croatica 74/3 ta bl e 3. r ar e ea rt h el em en ts (r ee ) c on te nt s ( pp m ) i n th e or e sa m pl es . sa m pl e pp m e1 e3 e6 e7 e9 e10 e13 e14 e15 e16 e17 e18 e19 e20 e21 e22 e23 e24 e25 e26 m in . m ax . av e. la 2. 80 14 .0 0 10 .0 0 6. 00 15 .2 0 0. 60 2. 60 2. 00 2. 70 13 .0 0 9. 90 5. 60 15 .1 0 0. 50 2. 40 1. 90 3. 00 15 .2 0 2. 40 6. 57 0. 50 15 .2 0 6. 57 ce 2. 70 24 .3 0 16 .1 0 11 .1 0 20 .8 0 0. 20 2. 90 2. 00 2. 60 24 .5 0 15 .8 0 10 .5 0 19 .7 0 0. 40 2. 70 2. 20 2. 40 20 .3 0 0. 20 9. 55 0. 20 24 .5 0 9. 55 pr 0. 40 2. 30 1. 60 1. 10 2. 60 0. 10 0. 30 0. 20 0. 30 2. 40 1. 30 1. 30 2. 50 0. 10 0. 40 0. 20 2. 10 0. 30 1. 80 1. 12 0. 10 2. 60 1. 12 n d 1. 90 10 .1 0 7. 30 4. 50 11 .3 0 0. 20 1. 50 0. 80 1. 70 10 .5 0 6. 40 4. 60 10 .9 0 0. 20 1. 60 0. 70 8. 90 6. 90 1. 70 4. 83 0. 20 11 .3 0 4. 83 sm 0. 30 1. 80 1. 30 0. 80 2. 00 0. 10 0. 30 0. 10 0. 20 1. 60 1. 20 0. 60 1. 90 0. 10 0. 20 0. 10 0. 30 0. 40 0. 40 0. 72 0. 10 2. 00 0. 72 eu 0. 10 1. 40 1. 40 1. 10 0. 80 0. 70 1. 50 1. 20 0. 10 1. 20 1. 40 1. 20 0. 90 0. 60 1. 40 1. 60 0. 90 1. 30 0. 60 1. 02 0. 10 1. 60 1. 02 g d 0. 40 2. 00 1. 50 1. 00 2. 10 0. 10 0. 40 0. 20 0. 30 1. 80 1. 40 0. 90 2. 30 0. 10 0. 30 0. 20 0. 40 1. 50 0. 30 0. 91 0. 10 2. 30 0. 91 tb 0. 10 0. 30 0. 30 0. 20 0. 40 0. 10 0. 10 0. 10 0. 10 0. 20 0. 30 0. 40 0. 20 0. 10 0. 20 0. 30 0. 10 0. 20 0. 10 0. 20 0. 10 0. 40 0. 20 d y 0. 4 2. 40 1. 80 1. 10 2. 40 0. 10 0. 30 0. 10 0. 30 2. 30 1. 70 1. 30 2. 20 0. 10 0. 30 0. 10 0. 30 2. 10 1. 80 1. 15 0. 10 2. 40 1. 15 h o 0. 10 0. 50 0. 40 0. 30 0. 50 0. 10 0. 10 0. 10 0. 10 0. 40 0. 30 0. 40 0. 50 0. 10 0. 10 0. 20 0. 30 0. 50 0. 20 0. 27 0. 10 0. 50 0. 27 er 0. 3 1. 60 1. 20 0. 80 1. 50 0. 10 0. 20 0. 10 0. 30 1. 40 1. 60 0. 70 1. 20 0. 10 0. 20 0. 70 0. 10 0. 20 0. 70 0. 71 0. 10 1. 60 0. 71 tm 0. 10 0. 20 0. 20 0. 10 0. 20 0. 10 0. 10 0. 10 0. 10 0. 20 0. 30 0. 10 0. 20 0. 10 0. 10 0. 20 0. 30 0. 10 0. 10 0. 15 0. 10 0. 30 0. 15 yb 0. 20 1. 60 1. 30 0. 70 1. 40 0. 10 0. 20 0. 10 1. 10 0. 20 1. 50 1. 20 0. 60 1. 30 0. 10 0. 20 0. 10 0. 30 1. 40 0. 70 0. 10 1. 60 0. 72 lu 0. 10 0. 20 0. 20 0. 10 0. 20 0. 10 0. 10 0. 10 0. 10 0. 20 0. 20 0. 10 0. 20 0. 10 0. 10 0. 10 0. 20 0. 10 0. 20 0. 14 0. 10 0. 20 0. 14 y 4. 20 19 .4 0 15 .6 0 12 .0 0 19 .6 0 0. 70 5. 10 2. 50 4. 30 19 .2 0 14 .2 0 12 .5 0 19 .8 0 0. 50 5. 40 2. 40 9. 80 4. 80 5. 50 9. 25 0. 50 19 .8 0 9. 34 ∑r ee 9. 90 62 .7 0 44 .6 0 28 .9 0 61 .4 0 2. 70 10 .6 0 7. 20 10 .0 0 59 .9 0 43 .3 0 28 .9 0 58 .4 0 3. 90 10 .1 0 8. 70 19 .4 0 49 .4 0 11 .9 0 28 .0 4 2. 70 62 .7 0 28 .0 0 ∑l re e/ ∑h re e 4. 82 6. 13 5. 46 5. 72 6. 06 2. 38 6. 07 7. 00 3. 17 7. 94 4. 93 4. 67 6. 89 0. 95 6. 21 3. 35 9. 78 8. 88 1. 48 5. 63 0. 95 9. 78 5. 38 ce * 0. 47 0. 83 0. 77 0. 87 0. 65 0. 16 0. 56 0. 51 0. 49 0. 88 0. 79 0. 84 0. 62 0. 37 0. 54 0. 59 0. 24 0. 76 0. 02 0. 69 0. 02 0. 88 0. 58 pr * 1. 01 0. 84 0. 84 0. 89 0. 97 2. 85 0. 82 0. 90 0. 81 0. 85 0. 74 1. 07 0. 97 2. 02 1. 10 0. 92 2. 59 0. 14 17 .6 1 0. 94 0. 14 17 .6 1 1. 94 ce an om -0 .3 2 -0 .0 7 -0 .1 1 -0 .0 5 -0 .1 8 -0 .7 5 -0 .2 5 -0 .2 8 -0 .3 2 -0 .0 4 -0 .1 0 -0 .0 5 -0 .2 0 -0 .3 8 -0 .2 5 -0 .2 1 -0 .5 8 -0 .1 6 -1 .3 9 -0 .1 5 -1 .3 9 -0 .0 4 -0 .2 9 eu * 0. 88 2. 18 2. 99 3. 72 1. 14 20 .2 4 13 .2 5 48 .1 0 1. 27 2. 10 3. 23 5. 09 1. 30 17 .3 5 17 .8 0 36 .3 2 7. 95 5. 36 4. 66 3. 83 0. 88 48 .1 0 9. 94 la n /y b n 9. 37 5. 86 5. 15 5. 74 7. 27 4. 02 8. 70 13 .3 9 1. 64 43 .5 2 4. 42 3. 12 16 .8 5 0. 26 16 .0 7 6. 36 20 .0 9 33 .9 2 1. 15 6. 29 0. 26 43 .5 2 10 .6 6 y/ h o 42 .0 0 38 .8 0 39 .0 0 40 .0 0 39 .2 0 7. 00 51 .0 0 25 .0 0 43 .0 0 48 .0 0 47 .3 3 31 .2 5 39 .6 0 5. 00 54 .0 0 12 .0 0 32 .6 7 9. 60 27 .5 0 33 .7 9 5. 00 54 .0 0 33 .2 9 tb /y b 2. 20 0. 83 1. 02 1. 26 1. 26 4. 41 2. 20 4. 41 0. 40 4. 41 0. 88 1. 47 1. 47 0. 34 8. 82 6. 61 4. 41 2. 94 0. 31 1. 26 0. 31 8. 82 2. 55 ce * = ce n /[2 /3 la n +1 /3 pr n ] σl re e = la +c e+ pr +n d+ sm +e u eu * = eu no rm /[2 /3 sm no rm +1 /3 g d n or m ] σh re e = g d+ tb +d y+ h o+ er +t m +y b+ lu ce an om = lo g [3 x ce n /(2 x l a n + n d n )] pr * = pr n /(c e n × n d n )1/ 2 g eologia c roatica 295öksüz and kaya: genesis of ferromanganese deposits from the central anatolian province, yozgat-aşağı eğerci village-turkey ... thermal source of mineralization (ramdohr, 1980; göymen & koç, 2000). additionally, goethite in the study area contains widely observed colloidal textures (fig. 5c-f), which are known to be sedimentation markers (schwartz, 1951). goethite, which also shows brecciated structures, is another indicator of sedimentary formation (fig. 4a, b). 5. results 5.1. trace and major elements ore samples from the study area had mn contents of 7.1-42.8 wt% (average 21.4 wt%) and fe contents of 0.1-30.2 (average 11.0 wt%). the mn/fe ratio was 0.6-187.7 (average 34.9) (table 1). eğerci­village­ferromanganese­mineralization­had­al2o3/tio2 ratios determined as 0.5-54.0 (ave. 8.0) (table 1). the samples from the deposit in this study had co/ni values above 2 for 4 samples and below 1 for 16 samples (table 2). ore sample v/(v+ni) ratios were below 0.60 for 8 samples, but above 0.60 for 12 samples (table 2). the mo and co contents in ore samples were 2.90-38.50 ppm (average 21.64 ppm) and 4.20-45.60 ppm (ave. 26.94) in the study area, respectively (table 2). the ba and as concentrations were 148.40-6315 ppm (avera ge 3687.93 ppm) and 15.20-412.00 ppm (ave. 153.29 ppm) in ore samples in the study area, respectively (table 2). samples from the study area had sr/ba ratios from 0.07-1.32 (ave. 0.28). the geochemical data for ore samples from the study area were plotted on a fe-(ni+co+cu)x10-mn ternary diagram (fig. 6a; bonatti et al., 1972). accordingly, all samples were distributed­in­the­hydrothermal­field.­ the source diagram determined with the na/mg ratio (nicholson 1992) showed that all samples were distributed in the freshwater­field­(fig.­6b).­fig.­6c­shows­the­fe/ti­ratio­plotted­ against al/(al+fe+mn) (fig. 6c; bostrom et al., 1976). on the 10×mgo-fe2o3-mno2 (conly et al., 2011) ternary diagram, ore samples were distributed in the marine hydrothermal, continental hydrothermal, marine hydrogenetic and freshwater­hydrogenetic­fields­(fig.­6d).­ 5.2. ree geochemistry the ree content of samples was used to assess the geochemical parameters of ore mineralization in the study area. ree, commonly used for assessing sources, were analyzed in 20 ore samples taken from the study area. analysis of the results and some calculations are given in table 3. σree data had values from 2.70-62.70 ppm with an average (ave.) 28.00 ppm. additionally, the lree/hree ratio in ore samples from the study area was 0.95-9.78 (ave. 5.38) and this value shows that lree values were enriched compared to hree values. this enrichment is 0.31-8.82 (ave. 2.55) ratios (fig. 7). additionally, eu and ce anomalies were assessed. ree data were normalized to chondrite and plotted on spider diagrams (fig. 7). as seen on the spider diagram for the eu anomaly, there is a high positive anomaly (fig. 7). when anomaly values are calculated with the formula eu*=eun/ [2/3smn+1/3gdn], apart from one sample, all displayed a high positive anomaly (0.88-48.10, ave 9.94) (tablo 3). in some situations, la enrichment causes false-negative ce anomalies (bau & dulski, 1999; kato et al., 2006; planavsky et al., 2010). for­this­reason,­the­ce*­anomaly­is­determined­with­two­different calculations. ce*=cen/[2/3lan+1/3prn] and pr*=prn/ (cen×ndn)1/2 calculations were performed. with ce* calculations, negative anomalies were supported for all samples (0.020.88, ave 0.58) (tablo 3). as a result of pr* calculation, though 6 samples were observed to have a positive anomaly, 14 samples were observed to have a negative anomaly, and the negative anomaly observed in most samples supports the ce* calculations (table 3). ceanom data were calculated with the formula ceanom = log(3cen/(2lan+ndn) (wright et al., 1987). when data from table 4. microthermometric fluid inclusion data from eğerci village ferromanganese ore samples. sample no mineral vapor ratio fl types homog. mode te, oc tm-ice, oc th, oc salinity (wt% nacl equiv.) e-1 quartz 5–20 type iii liquid –33.8 –2.3 176 3.9 5–20 type iii liquid –37 –2 216 3.4 5–20 type iii liquid –37.7 –1.7 186 2.9 5–20 type iii liquid –37.6 –1.2 191 2.1 5–20 type iii liquid –42.6 –1.3 205 2.2 30–60 type i vapor –1.4 354 2.4 5–20 type iii liquid –1.4 163 2.4 30–60 type iii vapor –45.4 –6.4 422 9.8 5–20 tip iii liquid –34.1 –1.7 227 2.9 5–20 type iii liquid –44.7 –2.4 236 4.0 30–60 type i vapor –47.8 –5.6 382 8.7 30–60 type i vapor –33.8 –1.5 347 2.6 20–30 tip ii liquid –36.9 –1.4 298 2.4 e-2 quartz 5./20 type iii liquid –34.8 –1.6 221 2.7 5–20 type iii liquid –40 –1.1 231 1.9 20–30 tip ii liquid –34.5 –1.1 304 1.9 5–20 type iii liquid –46 –1.6 217 2.7 20–30 type ii liquid –1.6 269 2.7 20–30 type ii liquid –38.1 –1.7 301 2.9 5–20 type iii liquid –1.6 191 2.7 5–20 type iii liquid –37.3 –1.8 209 3.1 30–60 type i vapor –1.1 346 1.9 30–60 type i vapor –1.5 377 2.6 5–20 type iii liquid 187 e-3 quartz 30/60 type i vapor –40.8 –6.1 397 9.4 30–60 type i vapor –5.4 361 8.5 30–60 type i vapor –44.2 –6.2 374 9.6 30–60 type i vapor –46 –7.3 431 11.0 30–60 type i vapor –49.9 –5.9 338 9.2 30–60 type i vapor –7.9 401 11.7 30–60 type i vapor –6 411 9.3 30–60 type i vapor –47.3 –8.1 417 12.0 30–60 type i vapor –9.4 438 13.5 e-4 quartz 40–60 type i vapor –43.3 –1.3 367 2.2 40–60 type i vapor –46.8 –10.5 406 14.7 20–30 type ii liquid –1.4 319 2.4 5–20 tip iii liquid –2 143 3.4 40–60 type i vapor –1.4 376 2.4 40–60 type i vapor –1.5 394 2.6 40–60 type i vapor –3.8 362 6.2 20–30 type ii liquid –2.9 277 4.8 20–30 type ii liquid –2.4 296 4.0 20–30 type ii liquid –3.1 284 5.1 40–60 type i vapor –2.4 388 4.0 g eo lo gi a c ro at ic a 296 geologia croatica 74/3 the­study­area­are­noted,­fifteen­samples­had­values­smaller­than­ ­0.1,­while­five­samples­had­values­larger­than­­0.1­(table­3). in­the­eğerci­village­ferromanganese­deposits,­the­y/ho­ratio was determined to be 33.29 (table 3). 5.3. fluid inclusion petrography and microthermometry fluid inclusion studies were performed on four samples taken from­quartz­veins­with­nearly­1­cm­thickness­located­within­carbonate­rocks­in­the­eğerci­village­ferromanganese­mineralization.­along­the­veins,­quartz­crystals­grow­from­the­surfaces­of­ the wall rock towards the centre of the veins, and they have zoned growth structures (fig. 8a). in this structure, twinned growth zones are found symmetrically on both sides of the veins, and in the­final­stage,­quartz­crystals­fill­the­cavity­in­the­centre­of­these­ growth zones. accordingly, zone 1 and zone 2 correspond to the stage­i­and­stage­ii­quartz­formations,­respectively,­while­the­final­stage­quartz­filling­in­the­centre­is­equivalent­to­3rd stage figure 6. discrimination diagram of the eğerci ferromanganese mineralization. (a) fe-(ni+co+cu)x10-mn ternary diagram (bonatti et al., 1972); (b) na/mg bivariate diagram (nicholson, 1992); (c) fe/ti vs. al/(al+fe+mn) bivariate diagram (bostrom et al., 1976); (d) 10×mg-fe2o3–mno2–ternary diagram (conly et al., 2011). figure 7. chondrite normalized ree diagram for ore samples (normalization values are from evensen, 1978). g eologia c roatica 297öksüz and kaya: genesis of ferromanganese deposits from the central anatolian province, yozgat-aşağı eğerci village-turkey ... equation­proposed­by­bodnar­(1993)­with­results­reported­in­ table­4.­the­blank­rows­in­table­4­are­equivalent­to­parameters­ that could not be measured. according­to­this,­three­main­fluid­inclusion­types­were­identified­along­the­three­different­growth­zones­of­the­samples.­type­ i­fluid­inclusions­are­generally­observed­to­have­irregular­geometric shapes and rarely tube shapes (fig. 8c). in some cases, negative crystal-shaped inclusions were also observed (fig. 8d). the type i­fluid­inclusions­in­zone­1­had­sizes­from­20­to­30­µm.­these­fluid­ quartz­formation­(fig.­8b).­eutectic­temperatures­(te),­final­ice­ melting temperatures (tm-ice), and homogenization temperatures­(th)­of­the­fluid­inclusions­from­each­zone­were­measured­ by the microthermometric study, and the results are presentted in­table­4.­eutectic­temperatures­and­final­ice­melting­temperatures­of­some­fluid­inclusions­could­not­be­measured­due­to­the­ inclusion­size­being­very­small­and­not­being­sufficiently­transparent.­additionally,­the­salinity­of­these­inclusions,­equivalent­ to wt.% nacl were calculated using the tm-ice values with the figure 8. a. growth zonation of the quartz vein in the carbonate host rock, b) photomicrograph of the quartz crystals with zoned structure, c, d) type i fluid inclusions in the growth zone i, e) negative crystal-shaped type ii fluid inclusion in the growth zone ii, f ) irregular shaped type iii fluid inclusion in the final stage quartz vein, g) negative crystal-shaped type iii fluid inclusion in the last stage quartz vein. g eo lo gi a c ro at ic a 298 geologia croatica 74/3 ta bl e 5. m aj or a nd tr ac e el em en t c on te nt s o f v ar io us ty pe s o f m an ga ne se a nd fe rr om an ga ne se d ep os its . n um be r o f sa m pl es 7 28 22 15 13 11 14 7 13 23 10 20 20 co un tr y ch in a pa ki st an ira n ja pa n tu rk ey re gi on g ui ch i w az iri st an h az ar a be la zh ob so rk hv an d w ak as a u lu ke nt bi nk ılı c ca yi rli ka si m ag a ey m ir th is st ud y o rig in se di m en ta ry vo lc an o se di m en ta ry h yd ro th er m al h yd ro ge no us su bm ar in e hy dr ot he rm al h yd ro th er m al h yd ro th er m al h yd ro th er m al se di m en ta ry se di m en ta ry / di ag en et ic vo lc an o se di m en ta ry vo lc an o se di m en ta ry h yd ro th er m al h yd ro ge no us si o 2 ( % ) (-) 43 .6 9 9. 41 46 .2 1 (-) 40 .8 2 58 .1 6 13 .6 8 10 .6 5 63 .0 2 13 .4 3 16 .0 4 18 .1 7 ti o 2 ( % ) (-) 0. 32 0. 84 0. 53 0. 34 0. 03 0. 04 0. 10 0. 02 0. 03 0. 10 0. 02 0. 17 a l 2o 3 ( % ) (-) 0. 73 12 .5 3 1. 86 0. 80 0. 48 0. 55 2. 49 2. 85 0. 65 2. 95 0. 73 1. 14 fe 2o 3 ( % ) (-) 2. 96 20 .3 3 9. 85 5. 75 2. 29 0. 92 3. 72 2. 46 0. 68 14 .3 3 0. 26 16 .5 0 m no (% ) (-) 45 .8 8 33 .7 8 32 .9 9 42 .4 6 39 .4 7 32 .5 0 63 .7 8 33 .3 9 29 .2 2 40 .4 3 69 .9 1 27 .6 7 m go (% ) (-) 0. 60 0. 59 0. 72 0. 18 0. 07 0. 19 1. 99 1. 27 0. 20 12 .7 2 0. 59 0. 54 ca o (% ) (-) 1. 28 6. 43 1. 44 0. 75 0. 52 4. 15 4. 05 18 .9 6 0. 24 6. 82 2. 40 15 .7 6 n a 2 o (% ) (-) 0. 29 0. 07 0. 40 0. 30 0. 03 0. 04 0. 24 0. 39 0. 05 0. 06 0. 01 0. 15 k 2 o (% ) (-) 0. 22 0. 88 0. 58 1. 27 0. 06 0. 10 0. 05 0. 56 0. 11 0. 19 0. 05 0. 69 p 2 o 5 ( % ) (-) 0. 25 3. 73 0. 23 0. 13 0. 06 0. 10 0. 18 0. 31 0. 04 0. 08 0. 07 0. 20 ba (p pm ) 21 2. 56 41 5. 00 63 04 .0 0 (-) (-) 10 38 .3 4 13 .7 9 42 7. 00 68 92 .0 0 12 29 .4 0 27 19 .4 0 23 64 .7 0 36 87 .9 3 v (p pm ) 16 7. 86 14 4. 00 57 3. 00 (-) (-) 30 .6 8 25 8. 00 (-) 10 6. 00 14 3. 70 10 6. 10 13 2. 00 13 2. 68 cr (p pm ) 10 7. 21 46 .0 0 24 7. 00 37 .2 7 (-) (-) 10 .0 0 (-) 26 .0 0 13 .7 0 10 .0 0 (-) 21 .6 0 co (p pm ) 4. 77 11 .0 0 40 4. 00 21 .2 0 12 5. 38 33 .3 5 2. 00 13 .0 0 59 .0 0 25 .2 1 49 .5 0 10 3. 50 26 .9 4 n i ( pp m ) 89 .3 9 36 .0 0 30 5. 00 17 .9 3 28 8. 46 98 .6 1 28 .0 0 10 .0 0 16 7. 00 69 .4 0 23 .0 0 67 .3 5 74 .6 5 cu (p pm ) 31 .0 3 72 .0 0 37 5. 00 10 1. 00 20 .4 5 16 1. 18 50 .0 0 56 .0 0 26 .0 0 15 4. 90 12 6. 80 80 .5 0 20 6. 27 zn (p pm ) 13 7. 36 64 .0 0 58 0. 00 71 .0 7 23 0. 94 64 .1 2 26 .0 0 70 .0 0 49 .0 0 66 .7 0 63 .5 0 62 .4 5 (-) pb (p pm ) 16 .4 9 49 .0 0 23 57 .0 0 53 .3 3 46 4. 68 6. 56 11 2. 00 65 .0 0 (-) 6. 50 53 .5 0 9. 33 36 .0 4 th (p pm ) (-) 2. 00 31 .0 0 (-) (-) 0. 28 2. 00 (-) (-) 0. 40 43 3. 20 0. 57 1. 10 rb (p pm ) 37 .8 9 2. 00 24 .0 0 (-) (-) 3. 60 2. 00 (-) (-) 2. 90 5. 00 0. 77 27 .1 6 sr (p pm ) 74 1. 34 (-) (-) (-) (-) 66 7. 65 85 .0 0 18 5. 00 21 00 .0 0 24 3. 40 25 5. 00 11 6. 47 53 7. 32 y (p pm ) 21 .7 5 (-) (-) (-) (-) 5. 00 (-) 15 .0 0 33 .0 0 22 .2 0 8. 45 9. 34 n b (p pm ) 6. 70 (-) (-) (-) (-) 0. 27 3. 00 (-) (-) 0. 70 11 .1 0 0. 15 1. 27 zr (p pm ) (-) (-) (-) (-) (-) 5. 87 12 .0 0 (-) 32 .0 0 4. 00 26 .9 0 8. 46 31 .7 1 m n/ fe (-) 19 9. 00 2. 16 0. 27 10 5. 46 11 5. 47 39 .0 0 18 .9 8 15 .0 3 97 .1 7 12 .0 2 88 0. 33 34 .9 2 a l 2o 3/ ti o 2 (-) 2. 28 14 .9 2 3. 49 2. 35 15 .5 3 13 .7 5 24 .9 0 14 2. 50 21 .6 7 29 .5 0 32 .5 3 8. 03 co /n i 0. 05 0. 31 1. 32 1. 61 0. 45 0. 81 0. 07 1. 30 0. 35 0. 36 2. 15 1. 54 0. 61 co /z n 0. 03 0. 17 0. 70 0. 37 0. 57 0. 81 0. 08 0. 19 1. 20 0. 38 0. 78 2. 24 (-) (-) : t he re is n o an al ys is g eologia c roatica 299öksüz and kaya: genesis of ferromanganese deposits from the central anatolian province, yozgat-aşağı eğerci village-turkey ... inclusions­have­two­phases­and­contain­fluid­and­vapour,­and­vapour rates vary between 40 and 60% (fig. 8c, d). these inclusions are­isolated­from­the­other­fluid­inclusions,­and­they­are­homo­ genized into the gas phase during the heating process. the eutectic temperatures of these inclusions were measured between -33.8 and -49.9 °c. when comparing these te temperatures­with­the­specific­eutectic­temperatures­of­the­different­salt­ compositions, type i inclusions were very close to those for inclusions with composition in the h2o-mgcl2-fecl2-cacl2 system (roedder, 1984; shepherd et al., 1985) (fig. 10). the final­ice­melting­temperatures­of­type­i­inclusions­were­measured­ between -1.1 to -10.5 °c. according to these values, the salinity of these inclusions was calculated to vary from 1.9 to 14.7 wt. % nacl­equiv.­according­to­bodnar­(1993).­the­homogenization­ temperatures­for­type­i­fluid­inclusions­were­measured­as­338­to­ 438 °c. type­ii­fluid­inclusions­were­observed­in­growth­zone­2­in­ the­samples­(fig.­8a,­b).­these­are­two­phase­liquid­rich­inclusions,­and­vapour/liquid­ratios­vary­between­20­30­%.­type­ii­ fluid­inclusions­are­generally­irregular,­but­ellipsoidal,­tubular,­and­ negative­crystal­shapes­were­also­defined­(fig.­8e).­the­inclusion­ sizes­are­highly­variable,­ranging­from­10­to­50­µm.­during­microthermometric­measurements,­type­ii­fluid­inclusions­homoge­ nized­in­the­liquid­phase.­the­te­temperatures­were­measured­ between -34.5 and -38.1 °c, which correspond to the h2o-fecl2mgcl2­fluid­salt­systems­according­to­shepherd­et­al.­(1985).­ the tm-ice temperatures of type ii inclusions were measured in the range of -1.1 to -3.1 °c. the salinities calculated according to these­values­range­from­1.9­to­5.2­wt.­%­nacl­equiv.­type­ii­fluid­ inclusion had th temperatures varying from 269 to 319 °c. type­iii­fluid­ inclusions­were­found­ in­ the­centre­of­ the­ quartz­zones­equivalent­to­the­final­growth­stage­(fig.­8a,­b).­in­ addition to irregular geometric shapes (fig. 8f), tubes, and negative crystal shapes (fig. 8g) are present. these negative crystal shapes support that these inclusions are primary in origin. their sizes­vary­from­10­to­30­µm.­the­vapour/liquid­ratio­ranges­from­ 5 to 20% (fig. 8f, g) and homogenization of type iii inclusions occurred­in­the­liquid­phase.­eutectic­temperatures­of­the­type­ iii inclusions were very close to the type ii inclusions (between -33.8 and -46 °c). therefore salt compositions of the h2o-fecl2mgcl2 system, similar to the type ii inclusions, were also defined­for­the­type­iii­inclusions.­the­tm­ice­temperatures­varied­ from -1.1 to -2.4 °c, corresponding to the salinity range from 1.9 to­4.0­wt.%­nacl­equiv.­for­the­type­iii­inclusions.­homogenization temperatures of these inclusions were measured between 143 to 236 °c (table 4). 6. discussion mineralization­in­the­study­area­was­investigated­with­field­and­ geochemical studies and the source was interpreted. major and trace element concentrations and the behaviour of these elements (associations)­are­frequently­used­in­manganese­and­ferromanganese deposits (öksüz, 2011b; polgari et al., 2012; zarasvandi et al., 2013). fe/mn ratios of the manganese and ferromanganese deposits have been calculated by various studies in the alpine-himalaya belt in turkey and the world (choi & hariya­1992;­öztürk­1993;­gülteki̇n­1998;­koç­et­al.,­ 2000; xie et al., 2006; shah &­moon,­2007;­karakuş­et­ al., 2010; zarasvandi et al., 2016; narego et al., 2019; khan et al., 2020). our results display some similarities with the manganese deposits of guichi (chine, xie et. al., 2006), waziristan (pakistan, shah & moon, 2007), hazara (pakistan, shah & moon, 2007), bela (pakistan. narejo et. al., 2019), zhob (pakistan, khan et. al., 2020), sorkhvand (iran, zarasvandi et. al., 2016), wakasa (japan, choi & hariya, 1992), ulukent­ (turkey,­öztürk,­ 1993),­binkılıç­ (turkey,­gülfigure 10. te temperatures and equivalent salinity for all fluid inclusions in samples. figure 9. th histogram for all fluid inclusions in samples. g eo lo gi a c ro at ic a 300 geologia croatica 74/3 tekin,­ 1998),­ çayırlı­ (turkey,­ karakuş­ et.­ al.,­ 2010),­ kasımağa­(turkey,­koç­et­al.,­2000)­and­eymir­(turkey,­oksuz 2011a) in terms of the mineralizations. accordingly, the average mn/fe ratios in the manganese and ferromanganese deposits­of­waziristan,­bela,­zhob,­sorkhvand,­çayırlı,­kasımağa,­and­ eymir in the ophiolite belt manganese mineralizations are 199.00, 0.27, 105.46, 115.47, 97.17, 12.02, 880.33 respectively (table 5). in addition, the obtained results are very closely related to the manganese mineralizations of these deposits in turkey and the world.­according­to­this­data,­the­eğerci­village­ferromanganese­ deposit is compatible with hydrothermal exhalative manganese deposits discovered near submarine spreading centres (nicholson, 1992). in addition, the average mn/fe ratios in people services­are­now­able­to­provide­us­with­a­monthly­staff­list­which­ includes­our­al­colleagues­the­guichi,­ulukent,­and­binkılıç­regions indicates that the manganese formations were formed from a sedimentary origin. the mn/fe ratios were calculated as 18.98 and­15.03­in­ulukent­and­binkılıç­regions,­respectively­(table­5).­ the­average­mn/fe­ratios­are­not­informative­since­mn­fe­relationships­are­defined­as­mn/fe<1­for­the­lacustrine­environment,­ mn/fe=1­for­the­hydrogenous­origin,­and­0.1<mn/fe<10­for­sedex­deposits­(nicholson­et­al.,­1997). the al2o3/tio2­ratio­in­sediments­indicates­a­significant­degree­of­volcanic­matter­contribution­in­spite­of­a­lower­effect­from­ sediment transport or diagenesis (hayashi et al., 1997; sugitani et al., 1996). the al2o3/tio2 ratio in volcanic rocks is between 8–21 (hayashi et al., 1997; sugitani et al., 1996). al2o3/tio2 ratios in waziristan, bela, and zhob deposits were calculated as 2.28, 3.49, and 2.35, respectively (table 5). in addition, the values observed in hazara, sorkhvand, wakasa, ulukent, binkılıç,­çayırlı,­kasımağa,­and­the­eymir­regions­are­quite­high­ as 14.92, 15.53, 13.75, 142.50, 21.67, 29.50, and 32.53, respectively (table 5). al2o3/tio2 ratio in the study area also shows high values.­the­ratio­shows­significant­effects­of­volcanic­activity­on­ore­ formation­in­the­eğerci­village­ferromanganese­deposits. variable characteristics of co are closely related to ni. the co/ni ratio is commonly used to understand ore formation processes in manganese deposits (delian, 1994; fernandez & moro, 1998). especially when deciding on sedimentary environment and sedimentation, it is a guide for hot water sedimentation­on­the­seafloor­(toth,­1980).­according­to­this­data,­a­co/ ni­value­<1­indicates­a­sedimentary­source­(delian,­1994;­ fernandez & moro, 1998), while co/ni >1 indicates a deep marine environment (delian, 1994; nayan et al., 1994). co/ni ratios­in­guichi,­wazaristan,­zhob,­sorkhvand,­wakasa,­binkılıç,­ and­çayırlı­regions­are­0.05,­0.31,­0.45,­0.81,­0.07,­0.35­and­0.36,­ respectively, and are lower than 1 (table 5). in addition, it was observed­greater­than­1­in­hazara,­bela,­ulukent,­kasımağa,­and­ eymir regions (1.32, 1.61, 1.30, 2.00, 1.54, respectively). since this value is both below and above 1 in the ferromanganese deposits of­eğerci­village,­it­is­thought­that­both­deep­sea­and­sedimentary­ environments­may­be­effective­in­the­formation. according to hein et al. (2008), high ba and minor co, ni and cu contents in manganese oxides show leaching from organic-rich sediments or precipitation of barite at depth in hydrothermal­systems.­due­to­the­effect­of­sedimentation­and­volcanic­ activity, the ba concentration in hydrothermal solutions is higher than seawater (monnin et al., 2001). similarly, ba contents showed high values in waziristan, hazara, sorkhvand, ulukent, binkılıç,­çayırlı,­kasımağa,­and­the­eymir­regions­where­the­ sedimentary contribution is intense (415.00, 6304.00, 1038.34, 427.00, 6892.00, 1229.40.00, 2719.40, 2364.70, 3687.93, respectively). according to the very high ba content, the study area is characterized by mineralization with hydrothermal formation. high as content is a marker of sediment input to hydrothermal manganese (nicholson, 1992). as enrichment in the study area was 15.20–412.00 ppm (ave. 153.29 ppm) (table 2). this enrichment­may­be­a­marker­of­hydrothermal­fluids­(şaşmaz­et­ al., 2014). when the sr/ba ratio is examined, if this ratio is larger than 1, the environment is marine; if it is lower than 1, it indicates the presence of continental freshwater in the formation (xie et al., 2006; xu et al., 2011). this ratio is variable in sedimentary mn deposits (doe et al., 2013). in mn deposits with hydrothermal effects,­it­is­<0.01­(doe­et­al.,­2013).­samples­from­the­study­area­ had sr/ba ratio values of 0.07-1.32 (ave. 0.28). apart from two figure 11. a. th-salinity relationships for all fluid inclusions in samples. b. comparison of variation in th-salinity with solution behaviour in a variety of environments. g eologia c roatica 301öksüz and kaya: genesis of ferromanganese deposits from the central anatolian province, yozgat-aşağı eğerci village-turkey ... samples, all ore samples had a sr/ba ratio lower than 1 representing formation in a continental sedimentary environment for mineralization in the study area. vanadium is a very stable element during alteration (jiancheng et al., 2006). the v/(v+ni) value increases linked to the increase in continental contribution. additionally, oxic conditions are dominant at the time of aerobic microbial metabolic processes (jiancheng et al., 2006). if the v/(v+ni) ratio is lower than 0.60, it indicates anoxic conditions at the time of mineralization (marynowski et al., 2012). the ore sample v/(v+ni) ratios were below 0.60 for 8 samples, but above 0.60 for 12 samples (table 2). for this reason, oxic and anoxic conditions were dominant during mineralization occurring in the region. additionally, sedimentary formation in a deep marine environment­was­effective­on­mineralization.­ elements like as, cu, mo, pb, sb, sr, and v are enriched in hydrothermal­fluids­(nicholson,­1992).­when­these­elements­ are examined, enrichment was observed in all ore samples from the study area (table 2). low­mo­content­in­ferromanganese­ore­may­reflect­the­low­ temperature­of­hydrothermal­fluids­(hein­et.­al.,­2008;­şaşmaz­ et al., 2014). this value was 2.90–38.50 ppm (average 21.64 ppm) in the study area so mineralization in a low-temperature hydrothermal formation may be present (table 2). the co content in hydrothermal deposits is lower compared to hydrogenetic deposits. hence, a high co concentration is a marker of the deep marine environment (del rio salas et al., 2008). this data reflects­mineralization­with­a­hydrothermal­source­in­the­study­ area. different­major­and­trace­element­differentiation­diagrams­ are­used­by­many­researchers­for­differentiation­of­manganese­ deposits­with­different­sources­(adachi­et­al.,­1986;­bonatti­ et al., 1972; choi & hariya 1992; crerar et al., 1982; nicholson, 1992; peters, 1988; shah & moon, 2007; toth,­1980).­these­diagrams­are­used­to­differentiate­between­ hydrothermal (continental or marine) and hydrogenetic sources. the term hydrothermal is used for manganese oxides deposited by sedimentary-exhalative manganese mineralization in marine environments or direct deposition from hot springs in pools and geothermal water in terrestrial environments (nicholson, 1992). the term hydrogenetic is used for deposits formed by adsorption or slow precipitation of material dissolved in seawater (bonatti et al., 1972; crerar et al., 1982; nicholson, 1992). the geochemical data for ore samples from the study area were plotted on a fe-(ni+co+cu)x10-mn ternary diagram (fig. 7a; bonatti et al., 1972). accordingly, all samples were distributed­in­the­hydrothermal­field.­ the source diagram determined with the na/mg ratio (nicholson, 1992) showed that all samples were distributed in the­freshwater­field­(fig.­7b).­the­diagram­of­ the­fe/ti­ratio­ against al/(al+fe+mn) was drawn (bostrom et al., 1976). accordingly, the presence of a volcanic input into the mineralization processes was supported (fig. 7c). the σree data obtained from ferromanganese samples had values from 2.70-62.70, an average of 28.00. additionally, the lree/hree ratio in mineralized samples from the study area was 0.95-9.78 (ave 5.38) and this value shows enrichment in lree values compared to hree values. in hydrothermal solutions containing ore, hrees are less stable than lrees, so they primarily enrich lree during manganese mineralization (ruhlin & owen, 1986; zarasvandi et al., 2013). these σree values show that the mineralization is compatible with hydrothermal­deposits­(e.g.,­northeast­pacific­ocean­baby­bare­deposit;­ ree = 20.6–249.6 jiancheng et al., 2006), while they are very low compared to values from hydrogenetic deposits (e.g., hazara deposit;­σree=­791­ppm;­shah­& moon, 2007). it is known that­the­σree­contents­of­ferromanganese­hydrothermal­deposits are lower compared to the hydrogenous deposits (choi & hariya, 1992), while the σree values of the hydrothermal oxi­de­deposits­have­a­wider­range­(mills­et­al.,­2001;­şaşmaz­ et al., 2014). formation environments display variability for eu anomalies. the eu value for seawater is 0.61 ppm, while the value is close to 7 ppm in hydrothermal deposits. variations in ce anoma ly are close to 0.17 for seawater and 1.03 in the continental crust (danielson et al., 1992; manikyamba & naqvi, 1995; mishra et al., 2006; moriyama et al., 2008). ferromanganese samples from the study area had an eu anomaly of 0.88–48.10 (ave. 9.94). the ce anomaly value was 0.02–0.88 (ave. 0.58). when­both­anomalies­are­assessed,­the­effect­of­the­mixing­of­ seawater­and­hydrothermal­fluids­on­mineralization­may­be­considered. the positive eu anomaly in mineralized samples is a typical feature of modern manganese hydrothermal deposits in the oceanic environment. negative ce anomaly shows the prese nce of oxic ocean water (wright et al., 1987; koçak, 2020a, b). the ree data for mineralized samples in the study support the idea that manganese mineralization occurred as precipitation as a result of both hydrothermal solutions and mixing with seawater (danielson et al., 1992; manikyamba & naqvi, 1995; mishra et al., 2006; moriyama et al., 2008). when the ceanom values in the study area are noted, 15 samples had values lower than -0.1, while 5 samples had values larger than -0.1. these values show the environment had both oxic and anoxic characteristics. in mineralized samples, the y/ho ratio was determined as 33.29. this ratio is higher compared to hydrothermal solutions, so the presence of a hydrothermal source and continental derived environment may be suggested. the histogram for homogenization temperatures measured in­fluid­inclusion­studies­of­four­samples­is­presented­in­fig.­9.­ three­different­quartz­stages­were­identified­in­the­measured­ samples­and­there­are­3­different­data­intervals­on­the­histogram­ for­th­ temperatures­measured­ in­fluid­ inclusions­ from­these­ stages. accordingly, the distribution of data on the histogram indicates­3­different­solution­stages.­ additionally, the eutectic temperatures for four samples are provided in table 4. accordingly, all samples had eutectic temperatures­equivalent­to­different­phases,­ranging­from­­33.8­to­ -49.9 °c. when these eutectic temperatures are compared with the­eutectic­temperatures­for­different­salt­compositions­given­by­ shepherd et al. (1985) (fig. 10), all measurement results show fluid­inclusion­composition­was­comparable­with­h2o-cacl2nacl-fecl2-mgcl2. while­the­salinity­for­type­i­fluid­inclusions­varies­from­1.9­ to­14.7­wt.%­nacl­equiv.,­type­ii­and­iii­fluid­inclusions­had­ lower­salinity­values­of­1.9­to­5.1­wt.%­nacl­equiv.­accordingly,­ the­th­salinity­trend­for­type­i­fluid­inclusions­was­compatible­ with a dilution trend for hydrothermal solutions with surface solutions (fig. 11). this trend indicates that solutions with the partly high­salinity­in­type­i­fluid­inclusions­(may­have­a­magmatic­ source) mixed with solutions with low salinity (meteoric). in contrast,­type­ii­and­iii­fluid­inclusions­had­salinities­from­1.9­to­5.1­ wt.%­nacl­equiv.­which­indicate­they­formed­under­the­effect­of­ meteoric solutions. g eo lo gi a c ro at ic a 302 geologia croatica 74/3 7. conclusions 1.­ ­as­a­result­of­field­studies,­geochemical­and­petrographic­ investigations,­and­fluid­inclusion­studies,­mineralization­ may be considered to have formed in three stages. 2. additionally, the formation occurred by ferromanganese mineralization precipitating in both oxic and anoxic environments­with­hydrothermal­solutions­affected­by­mixing­with­ seawater. 3.­ ­according­to­fluid­inclusion­studies,­the­three­different­solution stages of mineralization can be said to have temperatures­of­338­438­°c­for­the­first­stage,­269­317­°c­for­the­se­ cond stage, and 143-236 °c for the third stage. the calculated salinity­concentrations­were­particularly­high­for­type­i­fluid­ inclusions­(1.9­14.7­wt.%­nacl­equiv.)­and­lower­for­type­ii­ and­iii­fluid­inclusions­(1.9­5.1­wt.%­nacl­equiv.).­decreasing salinity versus the th temperature trend in figure 11. indicates that mineralization formed from a mixture of magmatic and meteorically derived solutions. 4. in the mineralized samples, the y/ho ratio (33.29) is higher compared to hydrothermal solutions, so the presence of a hydrothermal source and continental derived environment may be suggested. 5. apart from two samples, all the ore samples had a sr/ba ratio lower than 1 representing formation in a continental sedimentary environment for mineralization in the study area. 6. in the region, magmatism developed in the form of plutonic activity within crystalline massifs and as submarine volcanism in the upper cretaceous and middle eocene periods. later it is thought there was variation in ore minerals with the­effect­of­meteoric­waters.­in­the­study­area,­the­first­phase­ of­mineralization­with­three­different­phases­of­bands­and­ stockwork structure at the basalt-limestone contact and within limestones is thought to have formed with volcanic activity in the middle eocene period. acknowledgment this study constitutes part of the msc., thesis of sümeyra kaya and the project with the code number 6601-fbe/19-332, supported by yozgat bozok university. references adachi, m., yamamoto, k. & sugisaki, r. (1986): hydrothermal chert and assoicated­siliceous­rocks­from­the­northern­pasific:­their­geological­significance­as­ indication of ocean ridge activity.– sedimentary geology, 47, 125–148. akçay, a.e., dönmez, m., kara, h., yergök, a.f. & esentürk, k. (2007): turkish geological maps series with a scale of 1/100000, yozgat-i33 map. mta, ankara, 80, 1–16. (in turkish) bau, m. &­dulski,­p.­(1999):­comparing­yttrium­and­rare­earths­in­hydrothermal­fluids from the mid-atlantic ridge: implications for y and ree behaviour during nearvent mixing and for the y/ho ratio of proterozoic seawater.– chemical geology, 15/1–2, 77–90. doi:10.1016/s0009-2541(98)00142-9 bodnar,­r.j.­(1993):­revised­equation­and­table­for­determining­the­freezing­point­depression of h2o-nacl solutions.– geochim. cosmochim. acta 57, 683–684. doi: 10.1016/0016-7037(93)90378-a bonatti,­e.,­kraemer,­t.­&­rydel,­h.­(1972):­classification­and­genesis­of­submarine iron-manganese deposits.– in: horn, d.r. (ed.): ferromanganese deposits on­the­ocean­floor.–­­national­science­foundation,­149–166. bolhar, r., kamber, b.s., moorbath, s., fedo, c.m. & whitehouse, m.j. (2004): characterisation of early archaean chemical sediments by traceelement signatures.– earth and planetary science letters, 222, 43–60. doi: 10.1016/j.epsl.2004.02.016 bostrom, k., joensuu, o., valdes, s., charm, w. & glaccum, r. (1976): geochemistry­and­origin­of­east­pacific­sediments­sampled­during­dsdp­leg­34.–­ in: yeats, r.s. & hart, a.s.r. (eds.): initial reports of the deep sea drilling project. 34, 556–574), u.s. government printing office. doi: 10.2973/dsdp. proc.34.149.1976 choi j.h. & hariya, y. (1992): geochemistry and depositional environment of mn oxide deposites in the tokora belt, norteastern hokkaido, japan.– economic geology, 87, 12. doi: 10.2113/gsecongeo.87.5.1265 conly, a.g., scott, s.d., & bellon, h. (2011): metalliferous manganese oxide mineralization associated with the boléo cu-co-zn district, mexico.– economic geology, 106/7, 1173–1196. doi: 10.2113/econgeo.106.7. 1173 crerar, d.a., namson, j., chyi, m.s., williams, l. & feigenson, m.d. (1982): manganiferous cherts of the franciscan assemblage: i. general geology, ancient and modern analogues, and implications for the hydrothermal convection at oceanic spreading centres.– economic geology, 77, 519–540. doi: 10.2113/gsecongeo.77.3.519 danielson,­a.,­mȍller,­p.­& dulski, p. (1992): the europium anomalies in banded­iron­formations­and­the­thermal­history­of­the­oceanic­crust.–­chemical­geology,­ 97, 89–100. doi: 10.1016/0009-2541(92)90137-t delian, f. (1994): geological and geochemical research of the manganese ore bed (in chinese), m1. weather publishing press, beijing. del rio salas, r., ruiz, j., ochoa-landín, l., noriega, o., barra, f., meza-figueroa, d. & paz-moreno, f. (2008): geology, geochemistry and re-os systematics of manganese deposits from the santa rosalía basin and adjacent areas in baja california sur, méxico.– mineralium deposita, 43/4, 467–482. https:// doi.org/10.1007/s00126-008-0177-3 doe, b.r., ayuso, r.a., futa, k. & peterman, z.e. (2013): evaluation of the sedimentary manganese deposits of mexico and morocco for determining lead and strontium isotopes in ancient seawater.– in: basu, a. & hart, s. (eds.): earth processes: reading the isotopic code. (1996), geophys. monogr. ser., vol. 95, 391–408. doi: 10.1029/gm095p0391 evensen, m.n., hamilton, p. & o’nions, r.k. (1978): rare-earth abundances in chondritic meteorites.– geochim. cosmochim acta, 42, 1199–1212. doi: 10.1016/0016-7037(78)90114-x fernandez, a. & moro, m.c. (1998): origin and depositional environment of ordovician stratiform iron mineralization from zamora (nw iberian peninsula).–mineralium deposita, 33, 606–619. doi: 10.1007/s001260050176 göymen, g. &­koç,­ş.­(2000):­ore­microscopy.–­ankara­university­science­faculty­ publish, 60. gültekin,­a.h.­(1998):­geochemistry­and­origin­of­the­oligocene­binkılıç­manganese­ deposit, thrace basin, turkey.– turkish journal of earth sciences, 7, 11–24. hayashi, k.i., fujisawa, h., holland, h.d. & ohmoto, h. (1997): geochemistry of 1.9 ga sedimentary rocks from northeastern labrador, canada.– geo chimica et cosmochimica acta, 61/19, 4115–4137. doi: 10.1016/s0016-7037(97)002147 hein, j.r., schulz, m.s., dunham, r.e., stern, r.j. & bloomer, s.h. (2008): diffuse­flow­hydrothermal­manganese­mineralization­along­the­active­mariana­and­ southern­izu­bonin­arc­system,­western­pasific.–­journal­of.geophysical­research,­ 113,­b08,­14.­doi:­10.1029/2007jb005432 jiancheng, x., xiaoyong, y. & jianguo, d. (2006): geochemical characteristics of sedimentary manganese deposit of guichi, anhui province, china.– journal of rare earths, 24, 374–380. doi: 10.1016/s1002-0721(06)60127-0 karakuş,­a.,­yavuz,­b.­&­koç,­ş.­(2010):­mineralogy­and­major­trace­element­geochemistry of the haymana manganese mineralizations, ankara, turkey.– geochemistry international, 48, 1014–1027. doi: 10.1134/s001670291010006x kato, y., yamaguchi, k.e. & ohmoto, h. (2006): rare earth elements in precambrian banded iron formations: secular change of ce and eu anomalies and evolution of atmospheric oxygen.– geological society of america bulletin, 198, 269–289. doi: 10.1130/2006.1198(16) ketin, i. (1955): the geology of the yozgat region and the tectonic situation of the central anatolian massif.– the bulletin of the geological society of turkey, 6/1, 1–40. ketin, i. (1966): tectonic units of anatolia.– bulletin of the mineral research and exploration institute, 66, 20–34. khan, m.a, kakar, m.i., ulrich, t., ali, l., kerr, a.c., mahmood, k. & siddiqui, r.h. (2020): genesis of manganese deposits in the ali khanzai block of the zhob ophiolite, pakistan: inferences from geochemistry and mineralogy.– journal of earth science, 31/5, 884–895. doi: 10.1007/s12583-020-1337-3 koçak,­i.­(2020a):­sarıhıdır­manganese­mineralization­related­to­travertine,­central­anatolian volcanic province, turkey.– geodinamica acta, 32/1, 11–24. doi: 10.1080/09853111.2020.1829904 koçak, i. (2020b): geochemistry of the igdekoy-doganlar na-ca borate deposit, emet province (western anatolia, turkey).– geological quarterly, 64/3, 807–817. doi: 10.7306/gq.1555 koç,­ş.,­özmen,­ö.­&­öksüz­n.­(2000):­geochemistry­characteristic­of­kasimaga­ (keskin­kırıkkale)­manganese­oxide­mineralizations.–­mineral­research­and­exploration­magazine,­122,­107–120.­ krauskopf, k.b. (1989): introduction to geochemistry.– mcgraw-hill international editions, auckland. manikyamba, c. &­naqvi,­s.m.­(1995):­geochemistry­of­fe­mn­formations­of­the­ archean­sandur­schist­belt,­india­­­­mixing­of­clastic­and­chemical­processes­at­a­ g eologia c roatica 303öksüz and kaya: genesis of ferromanganese deposits from the central anatolian province, yozgat-aşağı eğerci village-turkey ... shallow­ shelf.–­ precambrian­ research,­ 72,­ 69–95.­ doi:­ 10.1016/0301­ 9268(94)00050-2 marynowski,­l.,­zatoń,­m.,­rakociński,­m.,­filipiak,­p.,­kurkiewicz.­ s. & pearce, t.j. (2012): deciphering the upper famennian hangenberg black shale deposi-tional environments based on multi-proxy record.– palaeogeogr. palaeoclimatol. palaeoecology, 347, 66–86. doi: 10.1016/j.palaeo.2012.05.020 mills, r.a., wells, d. & roberts, s. (2001): genesis of ferromanganese crusts from­the­tag­hydrothermal­field.–­chemical­geology,­176,­3–293.­doi:10.1016/ s0009-2541(00)00404-6 mishra, p., mohapatra, b.k. & singh, p.p. (2006): mode of occurrence and characteristics­of­mn­ore­bodies­in­iron­ore­group­of­rocks,­north­orissa,­india­and­its­ significance­in­resource­evaluation.–­resource­geology,­56,­55–64.­doi:­10.1111/ j.1751-3928.2006.tb00268.x monnin, c., wheat, c.g., dupre, b., elderfield, h. & mottl, m.j. (2001): barium­geochemistry­in­sediment­pore­waters­and­formation­waters­of­the­oceanic­ crust­on­the­eastern­flank­of­the­juan­de­fuca­ridge­(odp­leg­168).–­geochem.­ geophys. geosyst., 2/1, 1008–1023. doi: 10.1029/2000gc000073 moriyama, t., panigrahi, m.k., pandit, d. & watanabe, y. (2008): rare earth element enrichment in late archean manganese deposits from the iron ore group, east­india.–­resource­geology,­58,­402–413.­doi:­10.1111/j.1751­3928.2008.00072.x narejo, a.a., shari a.m., fatima, n. & sohail, k. (2019): geochemistry and origin of mn deposits in the bela ophiolite complex, balochistan, pakistan.– journal of petroleum exploration and production technology, 9, 2543–2554. doi: 10.1007/ s13202-019-0742-6 nayan, j., rongfen, j. & ziyu, w. (1994): permian palaeogeography and geochemical environment in lower yangtze region, china.– petroleum industry press, beijing, 206. nicholson, k. (1992): genetic types of manganese oxide deposits in scotland: indicators of paleo ocean spreading rate and a devonian geochemical mobility boundary.–­economic­geology,­87,­1301–1309.­doi:­10.2113/gsecongeo.87.5.1301 nicholson, k., nayak, v.k. & nanda j.k. (1997): manganese ores of the ghoriajhor-monmunda area, sundergarh district, orissa, india: geochemical evidence for­a­mixed­mn­source.–­geological­society,­special­publications,­119/1,­117.­doi:­ 10.1144/gsl.sp.1997.119.01.08 oktay, f.y. (1981): the geology of the sedimentary cover of the central anatolian ­massif­around­savcılı­büyükoba­(kaman).–­itu­faculty­of­mining.­associate­ professor thesis, istanbul. ostwald, j. (1984): two varieties of lithiophorite in some australian deposit.– mineral.­mag.,­48,­383–388.­doi:­10.1180/minmag.1984.048.348.08 öksüz, n. (2011a): geochemical characteristics of the eymir (sorgun-yozgat) manganese­deposit,­turkey.–­journal­of­rare­earths,­29/3,­287–296.­doi:­10.1016/s1002­ 0721(10)60446-2 öksüz, n. (2011b): geochemistry and the origin of manganese mineralizations in derbent (yozgat) region.– bulletin of the earth sciences application and research centre of hacettepe university, 32/3, 213–234 (in turkish) öksüz,­n.­(2018):­mineralogical­findings­from­manganese­deposits­in­the­artova­ophiolite complex, derbent-eymir area, yozgat, turkey.– bulletin of the mineral research and­exploration,­156,­137–150.­doi:­10.19111/bulletinofmre.334245 öksüz,­n.,­koçak,­i̇.­& temiz, u. (2021): geochemical and tectonic characteristics of manganese mineralization in the yozgat re gion, turkey.– geological quarterly, 65/2,­31.­doi:­10.7306/gq.1599­­ öksüz, n. & okuyucu, n. (2014): mineralogy, geochemistry, and origin of buyukmahal manganese mineralization in the artova ophiolitic complex, yozgat, turkey.– journal­of­chemistry,­837972.­doi:­10.1155/2014/837972 özcan,­a.,­erkan,­a.,­keski̇n,­e.,­ora,l­a.,­ozer,­s.,­sumengen,­m.­& tekeli̇,­o.­(1980):­the­basic­geology­of­the­north­anatolian­fault­kırsehir­massif. ankara.– bulletin of the mineral research and exploration report number: 6722 (unpublished; in turkish) öztürk, h. (1993): manganese mineralizations in turkey: processes of formation and types.– istanbul university eng. fac. geological engineering pub., 43, 24. peters, t. (1988): geochemistry of manganese-bearing cherts associated with alpine ophiolites and the hawasina formations in oman.– marine geology, 84/3–4, ­229­238.­doi:­10.1016/0025­3227(88)90103­x­ planavsky, n., bekker, a.j., rouxel, o., kamber, b., hofmann, a., knudsen, a.g. & lyons, t.w. (2010): rare earth element and yttrium compositions of archean and paleoproterozoic fe formations revisited: new perspectives­on­the­significance­and­mechanisms­of­deposition.–­geochimica­et­cosmochimica­acta,­74,­6387–6405.­doi:­10.1016/j.gca.2010.07.021­­ polgári, m., hein, j.r, vigh, t., szabó-drubina m., fórizs, i., bíró l., müller, a. & toth a.l. (2012): microbial processes and the origin of the úrkút manganese­deposit.–­hungary­ore­geol.­rev.,­47,­87–109.­doi.10.1016/j.oregeorev.2011.10.001 ramdohr, p. (1980): the ore minerals and their intergrowth.– pergamon press, oxford, london, new york. roedder, e. (1984): fluid inclusions. reviews in mineralogy.– mineralogical society of america, washington, 12, 644. ruhlin, d.e. & owen, r.m. (1986): the rare earth element geochemistry of hydrothermal­sediments­from­the­east­pasific­rice:­examination­of­a­seawater­scavenging­ mechanism.–­gechimica­et­cosmochimica­acta,­50,­393–400.­doi:­10.1016/0016­ 7037(86)90192-4 schwartz,­g.m.­(1951):­classification­and­definitions­of­textures­and­mineral­structures­in­ores.–­economic­geology,­46,­578–591.­doi:­10.2113/gsecongeo.46.6.578 seymen,­i.­(1982):­the­geology­of­the­kırşehir­massif­around­kaman­(kırşehir).–­itu­ faculty­of­mining.­associate­professor­thesis­(unpublished),­164,­i̇stanbul. shah, m.t. &­moon,­c.j.­(2007):­manganese­and­ferromanganese­ores­from­different tectonic settings. in the nw himalayas, pakistan.– journal of asian earth sciences.­29,­455–465.­doi:­10.1016/j.jseaes.2005.11.002 shepherd, t.j., rankin, a.h. & aiderton, d.h.m. (1985): a practical guide to fluid inclusion studies.– blackie and son limited, glasgow (u.k.), 235. sugitani, k., horiuchi, y., adachi, m.& sugisaki, r. (1996): anomalously low al2o3/tio2 values for archean cherts from the pilbara block, western australia possible evidence for extensive chemical weathering on the early earth.– precambrian­research,­80/1–2,­49–76.­doi:­10.1016/s0301­9268(96)00005­8 sylvestrea, g., timoleona, n., nono, k., djibrila, g., jean, p.n. & marianne, n.f. (2015): petrology and geochemistry of the banded iron-formations from ntem complex greenstones belt, elom area, southern cameroon:implications for the origin and depositional environment.– chemie der erde, 75, 375–387. doi:10.1016/j.chemer.2015.08.001 şaşmaz,­a.,­türkyilmaz,­b.,­öztürk,­n.,­yavuz,­f.­& kumral, m. (2014): geology and geochemistry of middle eocene maden complex ferromanganese deposits from elazig-malatya region, eastern, turkey.– ore geology reviews, 56, 352–372. toth, j.r. (1980): deposition of submarine crusts rich in manganese and iron.– geol. soc. america bul., 91/1, 44–54. doi: 10.1130/0016-7606(1980)91%3c44:doscr i%3e2.0.co;2 wright, j., schrader, h. & holser, w.t. (1987): paleoredox variations in ancient oceans recorded by rare-earth elements in fossil apatite.– geochim cosmochim acta,­51,­631–644.­doi:­10.1016/0016­7037(87)90075­5 xie, j.c., yang, x.y., du, j.g. &­xu,­w.­(2006):­geochemical­characteristics­of­sedimentary­manganese­deposit­of­guichi,­anhui­province,­china.–­j.­rare­earths,­24/3,­ 374–380.­doi:­10.1016/s1002­0721(06)60127­0­ xu, b., ding, s., wang, y. & liu, q. (2011): geochemical characteristics of illite clay rocks from the shihezi formation in the hanxing mining area and its sedimentary environment.–­mining­science­and­technology,­21/4,­495–500.­doi:­10.1016/j. mstc.2011.06.006 zarasvandi, a., lentz, d., rezai, m. & pourkaseb, h. (2013): genesis of the nasirabad manganese occurrence, fars province, iran: geochemical evidences.– chemie­der­erde­geochemistry,­73,­495–508.­doi:10.1016/j.chemer.2013.02.003 zarasvandi, a., pourkaseb, h., sepahvand, m.r., raith, j. & rezaei, m. (2016): tracing of hydrothermal ore forming process in the sorkhvand manganese deposit, kermanshah province, iran.– arabian journal of geoscience., 9. 109–123. doi­10.1007/s12517­015­2237­1 2019 | 72/2 | 101–108 | 9 figs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the genus hemicytheria pokorný (1955) is one of the very abundant ostracod genera, important for the biostratigraphy of the late miocene of serbia and the pannonian basin system (sokač, 1963; sokač, 1972; krstić, 1973, 1985; rundić, 1997, 2006). for this reason, rundić (1991, 1997) gave more attention to the genus hemicytheria from the late miocene of lake pannon sediments of the belgrade vicinity and kolubara coal basin (50 km sw of belgrade). based on the distribution of this genus, a few ostracod biozones were established within the late miocene lake pannon (krstić, 1985; rundić, 1997; rundić et al., 2011). this exclusively fossil ostracod tolerated a salinity range between 3-18‰ (pipĺk, 2007). herein, we present one of the species of hemicytheria which has an interesting carapace pattern and has been the subject of a geometric morphometric study. morphological differences between the genera hemicytheria (pokorný, 1955) and tyrrhenocythere (ruggieri, 1955) were the focus of some studies. a few authors state that the genus tyrrhenocythere represents a descendant form and it occurs in the stratigraphic record after hemicytheria disappeared (olteanu & vekua, 1989; rundić, 2006; pipĺk, 2007). in fact, according to olteanu & vekua (1989), tyrrhenocythere is a ”hemicytheria with radial pore canals concentrated in fascicles”. the authors considered the arrangement of the radial canals as a qualitative leap, a specific adaptation, necessary in a particular ecological context. the studied species, hemicytheria setosa was first discovered more than 30 years ago. the first determination concerning this species, mentioned as aurila (hemicytheria) sp. (setosa) (krstić, 1985) contained the first photo but without a description. later, rundić (2002) highlighted some important features of some new hemicytheria species from the late miocene of serbia from the area of mali požarevac, including a full description of this species as a new one. this species was discovered sexual dimorphism and left-right asymmetry of carapace ornamentation in hemicytheria setosa rundić, 2002 vukica vujić1, ljupko rundić2 and tamara karan-žnidaršič3 1 university of belgrade, faculty of biology, department of genetics and evolutionary biology, studentski trg 16, 11000 belgrade, serbia; (vukica.vujic@bio.bg.ac.rs) 2 university of belgrade, faculty of mining and geology, department of regional geology, kamenička 6, 11000 belgrade, serbia; (ljupko.rundic@rgf.bg.ac.rs) 3 university of belgrade, faculty of biology, department of morphology, systematics and phylogeny of animals, studentski trg 16, 11000 belgrade, serbia; (corresponding author: ktamara@bio.bg.ac.rs) doi: 10.4154/gc.2019.07 abstract in biostratigraphic research of the upper miocene of the pannonian basin system, one of the frequently detected and important ostracod genera is hemicytheria. among more than 20 species of this genus, hemicytheria setosa is present in sandy facies of the lake pannon sediments in serbia and bosnia and herzegovina. the aims of this study were to describe sexual dimorphism and differences between left and right valve morphology in hemicytheria setosa. landmark based geometric morphometrics is applied on the grounds of existence of the homologue pattern of the fossae and pore conuli on the valve surface of this group of ostracods. significant differences between the sexes and between the left and right valves are detected in the present study. the obtained results indicate that applied methods and chosen landmarks could be useful in the studies of valve ornamentation-variation in fossil and recent ostracoda. together with other “caspibrackish” upper pannonian (late miocene) ostracods and rundić (2002) also mentioned that it has a relatively small and thick-shelled carapace. however, in h. setosa the size and shape of the reticula is different, sometimes with poorly developed second-order reticulation. this feature is not common for the genus hemicytheria that comprises more than 20 species from the middle – late miocene (sokač, 1972; jiřĺček, 1985; olteanu & vekua, 1989; olteanu, 2011). this form represents a very abundant ostracod species within the sandy facies of the long-lived lake pannon (late miocene) (rundić, 2006; kovács et al., 2016). additionally, some other ostracodologists from the area of the pannonian (pokorný, 1952, 1955; sokač, 1972; jiřĺček, 1985; pipĺk, 2007), and transylvanian and dacian basins (olteanu & vekua, 1989; olteanu & jipa, 2006; olteanu, 2011; kovács et al., 2016) discovered large differences in the sculpture of the carapace between the hemicytheria species during the period from the middle miocene (sarmatian) to the end of the late miocene (pannonian s. lato). most studies come from the sediments of the ancient lake pannon which was a remnant of the central paratethyan sea and existed during the late miocene (ca. 11.6 – 5.3 ma). apart from the studies of sokač (1972), rundić (1997, 2002), pipĺk (2007) and olteanu (2011), there are no publications that have focused on the genus hemicytheria. also, to our best knowledge there is no geometric morphometric study applied to this genus, although geometric morphometrics is used in study of the ostracoda (abe et al., 1988; baltanás & geiger, 1998; baltanás & danielopol, 2011; mazzini et al., 2014; aiello et al., 2016; karanovic et al., 2017). the aims of this research were to describe sexual dimorphism and differences between left and right valves in carapace ornamentation of hemicytheria setosa, using the landmark based geometric morphometrics. article history: manuscript received september 13, 2018 revised manuscript accepted january 15, 2019 available online june 3, 2019 keywords: shell morphology, ostracods, geometric morphometrics, valve reticulation pattern, late miocene, southern pannonian basin g eo lo gi a c ro at ic a geologia croatica 72/2102 2. geological background belgrade city area and its surroundings belongs to the southern part of the pannonian basin (pb) that has a dynamic geological evolution through the neogene (harzhauser & piller, 2007; marović et al., 2007). miocene sediments were deposited discordantly over mesozoic rocks and represent the infill of the paratethys sea or its successor – lake pannon (harzhauser & piller, 2007; harzhauser & mandic, 2008; rundić et al., 2011). early to middle miocene sediments of the pb and its southern part (e.g. serbia) show a transition from continental alluviallacustrine to fully marine environments (marović et al., 2007; pavelić & kovačić, 2018). extensional tectonics reached their maximum during the middle miocene rifting phase (ca. 16–11.6 ma) when marine water flooded the whole region (e.g. matenco & radivojević, 2012; radivojević & rundić, 2016). at the middle/late miocene boundary (11.6 ma) as a result of the tectonic uplift of the carpathians, the pb was isolated from marine influences and the long-lived lake pannon formed (magyar et al., 1999; ter borgh et al., 2013; sztanó et al., 2015). seven million years later, lake pannon was infilled by lacustrine and fluvial-deltaic sediments derived from the surrounding orogenic belts (magyar et al., 2013; radivojević & rundić, 2016) (fig. 1). the late miocene sediments contain numerous fossils (molluscs, ostracods, etc.) widely distributed in the belgrade city area and its vicinity (rundić, 1993; rundić et al., 2011). most of them have an endemic character and settled the littoral and sublittoral environs of the ancient lake pannon (magyar et al., 1999; rundić et al., 2011). among the ostracods, large numbers of originally freshwater taxa were recognized, candonids predominantly (krstić, 1973; rundić, 2006). however a lot of genera show brackish and so-called the “caspibrackish” character (similar to the modern caspian sea). among them, the genus hemicytheria and its species is very important for biostratigraphic zonation of the pannonian stage (krstić, 1973, 1985; rundić, 2006; kovács et al., 2016). generally, older low diversity ostracods from the early pannonian expanded to the abundant taxa during the late pannonian age. this interval is designated as the “bloom time” for many ostracods, both qualitatively and quantitatively (rundić, 2006). based on the stratigraphic division of the late miocene lake pannon province as well as the biostratigraphic zonation, the hemicytheria setosa interval corresponds to the early pannonian age (fig. 2). according to krstić (1973, 1985) and rundić (1997, 2006) this species is found in the fifth and sixth ostracod biozones (amplocypris abscissa and hemicytheria croatica). its discovery suggests the sublittoral/littoral environs of lake pannon. besides the studied area, hemicytheria setosa is found in the upper pannonian s.str. (late miocene) of serbia (e.g. kolubara basin, vrčin) and bosnia and herzegovina (north-eastern part of the mt. majevica) (rundić, 1993, 2002). figure 1. the pannonian basin and its southern and eastern margins (scilands, 2015). white rectangle indicates the studied area. g eologia c roatica vujić et al.: sexual dimorphism and left-right asymmetry of carapace ornamentation in hemicytheria setosa rundić, 2002 103 3. materials and methods 3.1. locality and the studied species the sample for this study is taken from the sandy facies of the lake pannon sediments, from the left tributary of the kokorin stream, djurinci near mali požarevac, central serbia, 44°31’51.70”n, 20°38’49.21”e at an altitude of 187 m a.s.l. (see fig. 1). this species has a small, thick-shelled trapezoidal carapace. convexity is considerable, highest in the anterior part. the straight or slightly arched dorsal margin descends obliquely toward the posterior part. the ventral margin is straight or slightly concave in the first third, while the anterior margin is rounded, semicircular. posterior end perpendicular, in males posterio-ventrally extended. margins are without denticulation. surface reticulated. normal pore canals arranged in the suboval fossae separated with slightly faveolate muri. in the middle of the valves, fossae are tiny and shallow. there is a clearly arched ridge in the eye part, which is continuous with the anterior rib. ventral rib poorly developed. marginal zone broad. hinge holoamphidont, in the juvenile forms poorly developed. other features are the same as the genus hemicytheria (rundić, 2002). class ostracoda latreille, 1802 order podocopida sars, 1866 superfamily cytheroidea baird, 1850 family hemicytheridae puri, 1953 subfamily hemicytherinae puri, 1953 genus hemicytheria pokorný, 1955 species hemicytheria setosa rundić, 2002 synonymy: 1985 aurila (hemicytheria) sp. (setosa) – krstić, pl.14, fig.1 1991 hemicytheria setosa krstić – rundić, pl.1, figs.1-4 1997 hemicytheria setosa n. sp. rundić & krstić – rundić, p.66-67, pl.10 figs.1-4 2002 hemicytheria setosa n. sp. – rundić, p.138-139, pl. 1, figs.1-6 3.2. material preparation and applied analyses the field campaign and sampling were performed during the autumn of 1992. eight bulk sandy samples (ca. 400 g) have been taken from the kokorin stream. after the standard procedure of washing and sieving (meshes from 0.6-0.125mm) and h2s2 treatment, ostracods were picked and analysed under an olympus bh2 stereomicroscope (faculty of mining and geology, university of belgrade). some of the samples are very rich in ostracod content (more than 350 specimens including both carapaces and valves). those samples marked as 1/92os and 1a/92os contain more than 300 adult h. setosa specimens of both sexes. the ostracod collection is stored at faculty of mining and geology, university of belgrade. in this study, the female and male valves were photographed on the stereomicroscope discovery v.8 with a zeiss camera icc1 in axiovision 4.6.3 software (carl zeiss, jena, germany). to compare left-right asymmetry, all photographs are flipped to the left orientation prior to the landmark placement. to determine shape differences between the sexes, as well as differences in left (lv) and right valve (rv) morphology, gefigure 2. a chronostratigraphic chart of the late miocene lake pannon (modified after neubauer et al., 2015). gray arrow marks the position of the studied interval. figure 3. position of landmarks on the carapace of h. setosa (female left valve sem image modified from rundić, 1991). g eo lo gi a c ro at ic a geologia croatica 72/2104 ometric morphometric analyses were used. in total, 19 landmarks are chosen based on the homology of the fossae in the hemicytheridae (al furaih, 1977; liebau, 1977; aiello et al., 2016). we placed landmarks on some of the fossal groups proposed by aiello et al. (2016). they are positioned on the pore conuli, recognizable as prominent ridges on the valve surface figure 4. differences in carapace cs between the sexes (a) and the sides of both sexes (b). the median with the first and the third quartiles is shown (in boxes), together with the range of variation and outliers. figure 5. principal component analyses and warp analyses in: (a) right and (b) left valves in both sexes (f white circle, m black circle). the pattern of morphological variation is illustrated using the position and size of vectors which influence on a thin plate spline deformation grid. figure 6. principal component analyses and warp analyses in: (a) females and (b) males (left valves grey circles, right valves white circles). the pattern of morphological variation is illustrated using the position and size of vectors which influence on a thin plate spline deformation grid. g eologia c roatica vujić et al.: sexual dimorphism and left-right asymmetry of carapace ornamentation in hemicytheria setosa rundić, 2002 105 (fig. 3). four landmarks on each of the first three series of fossae, that are parallel to the anterior margin, are placed between the fossae (1 – 12). also, four landmarks are set starting from the ocular riblet, running in a row that surrounds the subcentral tubercle of the valve (13 – 16). the last three landmarks are placed between the fossae on the valve rear ridge (17 – 19). all landmarks are locally defined and classified as type i according to bookstein (bookstein, 1991; zelditch et al., 2004). the program tpsdig2 (rohlf, 2008a) was used to place the landmarks on photographs of 21 lv and 22 rv of females and 28 lv and 30 rv of males (in total, 101 valves). to calculate the centroid size (cs) the coordgen6 program (sheets, 2003) was used. size in geometric morphometrics is noted as the centroid size that quantifies the spread of landmarks around their centroid (klingenberg, 2013). in this study, the centroid size of each specimen was determined based on the reference length on each picture. principal component analysis (pca) and canonical variate analysis (cva) were performed in the morphoj program (klingenberg, 2011). also, morphological variation of the valves shape and size was analysed by warp analysis in tpsrelw programme (rohlf, 2008b). the warp analyses show dispersal of each landmark and its distance from the centroid in the sample, while pca analysis exhibits total morphological variability in the sample. the shape analyses were done by canonical variate analysis which was performed based on values of procrustes coordinates and values of centroid size that is treated as the covariate in the analyses. additionally, cluster analysis based on procrustes distances from cva and the unweighted pair-group method using arithmetic averages (upgma) was performed. all statistical analyses were done in statistica 5.1 (statsoft, 1997) and r statistical software (r development core team, 2008). 4. results the results of the analyses indicated that the centroid size of the valves is statistically different between the sexes (p < 0.0001; fig. 4a). differences in the cs between the left and right valve of females and males separately are significant only in females (females: p < 0.0005; males: p < 0.334) (fig. 4b). intersexual morphological variability in valve shape and cs are shown on fig. 5. additionally, variability of valve shape and cs of left and right valves into the same sex are exhibited in fig. 6. results of cluster analysis show that the shape of the right and left valves in males is more morphologically similar in comparison with the shape of left and right of valves in females (fig. 7). the spatial relationship of the fossae and pore conuli on the valve surface is different between the sexes (fig. 8). the differences in shape are more prominent in the central and posterior part of the valves. the lateral protrusion of the valves in females is positioned further backward than in males, relative to the anterior part that does not show statistical differences in position between the sexes (fig. 8). the posterior part shows the opposite tendency, as the posterior ridge is moved forward in the females, and backward in the males (fig. 8). figure 7. valve shape similarities among left and right valves in both sexes are shown by the unweighted pair-group method using arithmetic averages (upgma). figure 8. intersexual carapace shape differences (white bars females, grey bars males). the pattern of the mentioned differences is illustrated using the position and size of vectors which influence on a thin plate spline deformation grid. g eo lo gi a c ro at ic a geologia croatica 72/2106 the differences in shape based on superficial ornamentation between left and right valves are detected in both sexes separately (fig. 9 a and b). in females, the variation is less prominent in the anterior part. the central and posterior part of the left and right valve differ in the ornamentation pattern, as the fossae on the lateral protrusion of the left valve are placed more downward, whereas the fossae on the posterior part are more upward. the opposite tendency is noted on the right valve of females (fig. 9 a). in males, the most conspicuous is the variation of the first anterior ridge, which is moved forward in comparison to the same ridge on the right valve. also, the fossae on the lateral protrusion of the left valve are placed more backward, whereas the posterior ridge of the left valve is more forward in comparison with the right valve (fig. 9 b). 5. discussion and conclusions the valve morphology is the most crucial for palaeontological identification. morphological variability of this trait is analyzed here in detail on an intersexual level and between left and right valves in hemicytheria setosa, bearing in mind that there is a lot of carapace morphological variation among species within the genus hemicytheria (e.g. sokač, 1972). the results of landmark based geometric morphometric analysis that is applied, suggest significant differences are present in the carapace shape between the sexes and between the left and right valves in hemicytheria setosa. in relation to other forms of the genus hemicytheria, this species shows variation in carapace sculpture. the polygonal to suboval fossae in combination with large semi-circular pits are the main characteristics that differentiate this form from others. namely, sokač (1972), rundić (1997, 2002, 2006) and pipĺk (2007) already mentioned there are hemicytheria species which have three types of valve ornamentation: pitted, reticulated and smooth. valve shape intersexual differences are already described in cytheroids (martins et al., 2017) and hemicytheridae, as “high-doomed and oval” in females and “more rectangular” in males (bate et al., 1981). the results of the present study show figure 9. carapace shape differences between left (grey bars) and right (white bars) valves in: (a) females and (b) males. the pattern of the aforementioned differences is illustrated using the position and size of vectors which influence on a thin plate spline deformation grid. g eologia c roatica vujić et al.: sexual dimorphism and left-right asymmetry of carapace ornamentation in hemicytheria setosa rundić, 2002 107 that the shape of the valve surface is in line with the findings of the aforementioned authors. the greatest differences between the sexes are noted in the posterior part of the valves, which are more elongated in males. that is in accordance with the findings of martins et al. (2017), who concluded that males have larger posterior parts and because of a large copulatory apparatus that is located beneath this part of the carapace. apart from intersexual differences in carapace ornamentation, results of this study represent the first assessment of differences in carapace ornamentation between left and right sides in some cyteroid species. it is interesting to note that left-right asymmetry in size between valves was present in females, but not in males. this notion needs to be more deeply investigated in further research. left-right asymmetry in females of h. setosa shows a different ornamentation pattern than in males, which adds one more characteristic to conspicuous intersexual differences. in females, the differences between sides are absent in the anterior region of the valves, whereas in the central and posterior part, placement of the fossae and pore conuli show movements in the vertical line. in males, the most differences between valves are in the anterior part, while the central and posterior valve surfaces, show differences in ornamentation along the horizontal line, that is the opposite in comparison with females. this research is the first attempt to explore a suitable method to assess valve ornamentation-variation and to suggest the choice of landmarks which could be useful in future, more extensive investigations, on a larger interspecific sample. acknowledgement the results of this study are a part of projects: no. 173025 “evolution in heterogeneous environments: adaptation mechanisms, biomonitoring and conservation of biodiversity” and no. 176015 “geodiversity, lithostratigraphy and geological evolution of the basins of the central balkan peninsula and adjacent areas”, approved and financed by the ministry of education, science and technological development of the republic of serbia. we are very grateful to valentina hajek-tadesse and an anonymous reviewer for the valuable comments that helped to improve the manuscript. we also express our gratitude to the editors alisa martek and tea fluksi for the support provided during publication process, as well as to julie robson for the improvements of the english language quality. references abe, k., reyment, r.a., bookstein, f.l., honigstein, a., almogi-labin, a., rosenfeld, a. & hermelin, o. (1988): microevolution in two species of ostracods from the santonian (cretaceous) of israel.– historical biology, 1, 303–322. doi: 10.1080/08912968809386481 aiello, g., barra, d. & parisi, r. (2016): intra-and interspecific shell variability of the genus urocythereis ruggieri, 1950 (ostracoda: hemicytheridae) in the la strea bay (ionian sea, italy).– european journal of taxonomy, 193, 1–35. doi: 10.5852/ejt.2016.193 al-furaih, a.a. (1977): cretaceous and palaeocene species of the ostracod horni­ brookella from saudi arabia.– palaeontology, 20/3, 483–502. baird, w. (1850): the natural history of the britich entomostraca.– ray society london, 364 p. baltanás, á. & danielopol, d. (2011): geometric morphometrics and its use in ostracod research: a short guide.– joannea geologie und paläontologie, 11, 235–272. baltanás, á. & geiger, w. (1998): intraspecific morphological variabilty: morphometry of valve outlines.– in: martens, k. (ed.): sex and parthenogenesis. backhuys publishers. rundle, s.d. & s.j., 127–142. bate, r.h., whittaker, j.e. & mayes, c.a. (1981): marine ostracoda from the galapagos islands and equador.– zoological journal of the linnean society, 73, 1–79. bookstein, f.l. (1991): morphometric tools for landmark data: geometry and biology.– cambridge university press, cambridge. doi: 10.1017/cbo9780511573064 harzhauser, m. & piller, w.e. (2007): benchmark data of a changing sea – palaeogeography, palaeobiogeography and events in the central paratethys during the miocene.‒ palaeogeography, palaeoclimatology, palaeoecology, 253, 8–31. doi: 10.1016/j.palaeo.2007.03.031 harzhauser, m. & mandic, o. (2008): neogene lake systems of central and south-eastern europe: faunal diversity, gradients and interrelations.‒ palaeogeography, palaeoclimatology, palaeoecology, 260, 417–434. doi: 10.1016/j.palaeo.2007.12.013 jiříček r. (1985): die ostracoden des pannonien.– in: papp, a., jambor, a. & steininger, f.f. (eds.): chronostratigraphie und neostratotypen, vii, m-6, pannonien (slavonien und serbien). akadémiai kiadó, budapest, 348–408. karanovic, i., lavtižar, v. & djurakic, m. (2017): a complete survey of normal pores on a smooth shell ostracod (crustacea): landmark-based versus outline geometric morphometrics.– journal of morphology, 278, 1091–1104. doi: 10.1002/ jmor.20696 kovács, e., magyar, i., sztanó, o. & pipĺk, r. (2016): pannonian ostracods from the southwestern transylvanian basin.– geologia croatica, 69/2, 213–229. doi: 10.4154/gc.2016.16 klingenberg, c.p. (2013): visualizations in geometric morphometrics: how to read and how to make graphs showing shape changes.– hystrix, 24, 15–24. klingenberg, c.p. (2011): morphoj: an integrated software package for geometric morphometrics.– molecular ecology resources, 11, 353–357. doi: 10.1111/j.1755-0998.2010.02924.x krstić, n. (1973): biostratigraphy of the congerian beds in the belgrade region on the basis of ostracoda with the description of the species of the genus amplocypris. institute for geological and mining explorations and investigation of nuclear and other minerals raw materias, monographs, vol. 4, 208 p. (in serbian, with an english abstract). krstić, n. (1985): ostracoden im pannonien der umbegung von belgrade.– in: papp, a. et al. (eds.): chronostratigraphie und neostratotypen, miozän m6, pannonien. akadémiai kiadó, budapest, 103–143. latreille, p.a. (1802): histoire naturelle générale et particulière des crustacés et des insectes.– tome 3. familles naturelles des genres. paris: f. dufart, xii + 467 p. liebau, a. (1977): carapace ornamentation of the ostracoda cytheracea: principles of evolution and functional significance.– aspects of ecology and zoogeography of recent and fossil ostracoda, 107–120. magyar, i., geary, d.h. & müller, p. (1999): paleogeographic evolution of the late miocene lake pannon in central europe.– palaeogeography, palaeoclimatology, palaeoecology, 147, 151–167. doi: 10.1016/s0031-0182(98)00155-2 magyar, i., radivojević, d., sztanó, o, synak, r., ujszászi, k. & pócsik, m. (2013): progradation of the paleo-danube shelf margin across the pannonian basin during the late miocene and early pliocene.– global and planetary change, 103, 168–173. doi: 10.1016/j.gloplacha.2012.06.007 marović, m., toljić, m., rundić, lj. & milivojević, j. (2007): neoalpine tectonics of serbia.– serbian geological society, ser. monographie, belgrade, 88 p. martins, m.j.f., hunt, g., lockwood, r., swaddle, j.p. & horne, d.j. (2017): correlation between investment in sexual traits and valve sexual dimorphism in cyprideis species (ostracoda).– plos one, 12/7, e0177791. doi: 10.1371/ journal.pone.0177791 matenco, l. & radivojević, d. (2012): on the formation and evolution of the pannonian basin: constraints derived from the structure of the junction area between the carpathians and dinarides.‒ tectonics, 31, tc6007, 18–49. doi: 10.1029/2012tc003206 mazzini, i., gliozzi, e., rosseti, g. & pieri, v. (2014): the ilyocypris puzzle: a multidisciplinary approach to the study of phenotypic variability.– international review of hydrobiology, 99/6, 395–408. doi: 10.1002/iroh.201301729 neubauer, t.a., harzhauser, m., kroh, a., georgopoulou, e. & mandic, o. (2015): a gastropod-based biogeographic scheme for the european neogene freshwater systems.– earth-science reviews, 143, 98–116. doi: 10.1016/j. earscirev.2015.01.010 olteanu, r. (2011): atlas of the pannonian and pontian ostracods from the eastern area of the pannonian basin.– geo-eco-marina, 17, 135–177. olteanu r. & vekua d. (1989): quelques considérations sur les genres tyrrheno­ cythere (ruggieri, 1955) et hemicytheria (pokorný, 1955) (ostracoda, crustacea) du néogène supérieur de la paratéthys.– geobios, 22, 65–79. doi: 10.1016/s0016-6995(89)80089-0 olteanu, r. & jipa, d. (2006): dacian basin environmental evolution during upper neogene within the paratethys domain.– geo-eco-marina, 12, 91–105. pavelić, d. & kovačić, m. (2018): sedimentology and stratigraphy of the neogene rift-type north croatian basin (pannonian basin system, croatia): a review.– marine and petroleum geology, 91, 455–469. doi: 10.1016/j.marpetgeo.2018.01.026 g eo lo gi a c ro at ic a geologia croatica 72/2108 pipĺk, r. (2007): phylogeny, palaeoecology, and invasion of non-marine waters by the late miocene hemicyhterid ostracod tyrrhenocythere from lake pannon.– acta palaeontologica polonica, 52/2, 351–368. pokorný, v. (1952): the ostracods of the so-called basal horizon of the subglobosa beds at hodonín (pliocene, inner alpine basin, czechoslovakia) [in czech with russian and english abstracts].– sborník ústředního ústavu geologického, 19, 229–396. pokorný, v. (1955): contribution to the morphology and taxonomy of the subfamily hemicytherinae puri 1953 (crustacea, ostracoda).– acta universitatis carolinae, geologica 3, 3–35. puri, h.s. (1953): contribution to the study of the miocene of the florida panhandle.– the florida geological survey, geological bulletin, 36/3, 217–345. r development core team (2008): rversion 3.5.1 (2018-07-02): a language and environment for statistical computing. r foundation for statistical computing, vienna, austria. available online at: http://www.r-project.org [verified 26 november 2018] radivojević, d. & rundić, lj. (2016): synrift and postrift miocene sediments of northern banat, serbia.– underground mining, 28, 39‒60. doi: 10.5937/ podrad1628039r rohlf, f.j. (2008a): tpsdig, version 2.12. ecology and evolution, suny at stony brook: stony brook, ny, usa. rohlf, f.j. (2008b): tpsrelw. version 1.46. ecology and evolution, suny at stony brook: stony brook, ny, usa. ruggieri, g. (1955): tyrrhenocythere, a new ostracode genus from the mediterranean.– journal of paleontology, 29, 698–699. rundić, lj. (1991): upper pannonian ostracods from the vicinity of mali požarevac.– annales géologiques de la pénninsule balkanique, 55/1, 213–220. rundić, lj. (1993): biostratigrafija gornjeg panona severoistočne majevice (bosna) na osnovu ostrakoda [biostratigraphy of the upper pannonian of northeastern majevica, bosnia based on ostracodes].– proceedings of geoinstitute, 28, 63–80. rundić, lj. (1997): biostratigrafija kaspibrakičnog neogena kolubarskog basena [bio­ stratigraphy of the caspibrackish neogene of kolubara basin – in croatian, with an english abstract].– unpubl. phd thesis, faculty of mining and geology, university of belgrade, 128 p. rundić, lj. (2002): some species of the genus hemicytheria, pokorny (ostracoda, crustacea) from the upper miocene of serbia.– annales géologiques de la pénninsule balkanique, 64, 137–151. doi: 10.2298/gabp0264137r rundić, lj. (2006): late miocene ostracodes of serbia: morphologic and palaeoenvironmental considerations.– annales géologiques de la pénninsule balkanique, 67, 89–100. doi: 10.2298/gabp0667089r rundić, lj., ganić, m., knežević, s. & soliman, a. (2011): upper miocene pannonian sediments from belgrade (serbia): new evidence and paleoenvironmental considerations.‒ geologica carpathica, 62/3, 267‒278. doi: 10.2478/v10096011-0021-z sars, g.o. (1866): oversigt af norges marine ostracoder.– forhandlinger i videnskabsselskabet i christiania, 130 p. scilands (2015): the shaded hypsometric maps of hungary, slovakia, slovenia, croatia, serbia, bosnia-herzegovina, montenegro.– available online at: http:// www.scilands.de/ sheets, h.d. (2003): ‘imp: integrated morphometrics package.’ (department of physics, canisius college: buffalo, ny, usa.) available online http://www3.canisius. edu/~sheets/morphsoft.html [verified 25 november 2018] sokač, a. (1963): panonska fauna ostrakoda donjeg selišta jugozapadno od gline [pannonian fauna of ostracoda of donje selište southwest of glina – in croatian].– geološki vjesnik, 15/2, 391–401. sokač, a. (1972): pannonian and pontian ostracode fauna of mt. medvednica.– palaeontologia jugoslavica, 11, 1–140, jazu, zagreb. statsoft, inc. (1997): ‘statistica’(statsoft: tulsa, ok, usa.) sztanó, o., sebe, k., csillag, g. & magyar, i. (2015): turbidites as indicators of paleotopography, upper miocene lake pannon, western mecsek mountains (hungary).‒ geologica carpathica, 66/4, 331–344. doi: 10.1515/geoca-2015-0029 ter borgh, m., vasiliev, i., stoica, m., knežević, s., matenco, l., krijgsman, w., rundić, lj. & cloething, s. (2013): the isolation of the pannonian basin (central paratethys): new constraints from magnetoand biostratigraphy.‒ global and planetary change, 103, 99–118. doi: 10.1016/j.gloplacha.2012.10.001 zelditch, m.l., swiderski, d.l., sheets, h.d. & fink, w.l. (2004): geometric morphometrics for biologists: a primer. elsevier, san diego. ab stra ct planktonic foraminifera were quantitatively analyzed across the santonian succession and their boundaries at the jebel ennahli and ettout sections, northern tunisia. the continuous sedimentary succession is dominated by hemipelagic facies, allowing a good biostratigraphic correlation for this time interval. fifty-fife planktonic foraminiferal species belonging to 13 genera have been identified. the distribution pattern of 17 heterohelicids and 38 trochospiral forms reveals the identification of 12 major bio-events and allows establishment of three zones based on heterohelicids and five zones based on trochospiral forms. trochospiral based zones are from the base to the top: 1) dicarinel­ la primitiva interval zone, 2) dicarinella concavata interval zone, 3) dicarinella asymetrica total range zone, 4) globotruncanita elevata/globotruncana arca concurrent range zone, and 5) globotruncanita ventricosa interval zone. the heterohelicid planktonic foraminiferal zones are: 1) pseudotextularia nuttalli interval zone, 2) sigalia carpatica interval zone, and 3) ventilabrella eggeri/planoglobuliina manuelensis concurrent range zone. the bioevents and planktonic foraminiferal zones were correlated with previously published works especially on tunisia and other areas. the lowest occurrence (lo) of dicarinella asymetrica is the only planktonic foraminiferal datum recorded across the coniacian/santonian boundary (csb). it occurs slightly below the lo of the inoceramid platyceramus cycloides cycloides representing a good proxy for the csb. the santonian/campanian boundary in the studied sections is characterized by a major faunal turnover represented by the lo of ventilabrella and planoglobulina and the lo of globotruncana and globotruncanita slightly above. the boundary interval is also characterized by the highest occurrence (ho) of sigalia, dicarinella, and whiteinella. keywords: santonian, biostratigraphy, planktonic foraminiferal, bioevents, globotruncanidae, heterohelicidae, tunisia. geologia croatica 67/2 111–126 8 figs. 1 pl. zagreb 2014 santonian planktonic foraminiferal biostratigraphy of the northern tunisia  1zaineb elamri, 2sherif farouk and 3dalila zaghbib-turki 1 university of kairouan, institute of arts and crafts, kasserine, 1200, tunisia 2 egyptian petroleum research institute, exploration department, nasr city, 11727, egypt; (geo.sherif@hotmail.com) 3 university of tunis-el manar, faculty of sciences, department of geology, campus universitaire 2092, tunisia doi: 10.4154/gc.2014.08 ous papers deal with the planktonic foraminiferal biostratigraphy of the upper cretaceous in tunisia (e.g. pervinquière 1903, 1907; pini, 1971; dalbiez, 1956; salaj, 1980; nederbragt, 1991; rami et al., 1997; robaszynski et al.; 2000; robaszynski & mzoughi 2010; bey et al., 2012). it is well-known that the tethyan, or low latitude assemblages are characterized by abundant, highly diverse planktonic foraminiferal assemblages, whereas those from the circum-antarctic region are characterized by low diversity and usually long-ranging planktonic taxa of simple morphology (petrizzo, 2000). many bio1. introduction northern tunisia corresponds to a fold thrust belt linking the north africa atlas and the sicilian apennine chains, called the peri-mediterranean orogenic arc (coward & ries, 2003). it was formed during the cenozoic following the collision between the african and european plates. upper cretaceous rocks in tunisia are characterized by widely distributed, deep marine facies, which are extremely rich in microfauna as well as macrofauna especially ammonites and inoceramids. therefore a considerable number of previgeologia croaticageologia croatica geologia croatica 67/2geologia croatica 112 stratigraphic studies have been conducted on the santonian deposits and their boundaries to define the global stratotype section and point (gssp) but comparison of the santonian planktonic foraminiferal bioevents noted in the tethyan province with other provinces has revealed variations in the stratigraphic ranges (farouk & faris, 2012). the olazagutia section (north spain) was approved as the gssp for the base of the santonian by the subcommission on cretaceous stratigraphy, and submitted to the international commission of stratigraphy (ics) in early 2012. the base of the coniacian / santonian boundary is placed at the lowest occurrence of the inoceramid bivalve cladocera­ mus undulatoplicatus (lamolda et al., 2007; lamol da, 2013). this marker species has not been previously recorded in tunisia. however, gradstein et al. (2012) noted that the olazagutia section is not ideal the biostratigraphic record may be incomplete and the abandoned quarry wall might be unsuitable for future sampling. an alternative candidate is ten mile creek, dallas county, texas (gale et al., 2007), where portions of the record are composed of over lapping sections. furthermore, the stratotype for the santonian – campanian (s/c) boundary is still in the process of ratification. the s/c transition interval has been studied in many sections in tunisia (e.g., nederbragt, 1991, 1993; salaj, 1980; arz, 1996; robaszynski, 1999; robaszynski et al., 2000; jarvis et al., 2002). the geographic applicability of biostatigraphic zonations is influenced by palaeolatitudinally controlled temperature gradients and the niche preferences of marker species (bralo wer, 1995). integration of trochospiral and heterohelicid bioevents in the present study allows a high-resolution biozonation, and increased ability to correlate between deep and shallower basins, owing to the different life strategies of the various families (e.g., li & keller, 1998; arz & molina, 2002). the main objectives of the present study are: 1) to define the major planktonic foraminiferal events; 2) to establish a high resolution planktonic foraminiferal biostratigraphic zonation based on the integration of trochospiral and heterohelicid forms; 3) to compare the planktonic foraminiferal bioevents from different palaeolatitudes; 4) to define the co nia ciansantonian and santonian-campanian stage boundaries. figure 1: a) location map of the studied sections. b & c) geologic map after http://www.erlm.tn/lithotheque/img/pdf/carte_geologique_500_000.pdf elamri et al.: santonian planktonic foraminiferal biostratigraphy of the northern tunisia geologia croatica 113 2. material and methods 151 rock samples were collected from the kef formation, sampled approximately every 50 cm from two exposed sections (fig. 1). the first section named the ettout section is located on the south eastern flank of the ellès syncline in central tunisia (35°56’59“n and 9°6’2“e), while the second section named the jebel ennahli section, is located in northeastern tunisia in the ariana area ~5 km from tunis city towards the north (36° 54’ 46’’ n 10° 09’ 09’’ e). from both sections, the samples are washed following the classic micropalaeontological method. about 200 g of dry rock samfigure 2: stratigraphic correlation of the studied sections in the northern tunisia, showing the (lowest and highest occurrence) of planktonic marker species. geologia croatica 67/2geologia croatica 114 ta bl e 1: r el at iv e pe rc en t a bu nd an ce s a t e tt ou t s ec tio n se ct io n, c al cu la te d fo r t he > 6 3 µm fr ac tio n on 3 00 -5 00 sp ec im en s. sa m pl e no . et 58 et 61 et 60 e t6 7 et 68 et 69 et 71 et 73 et 75 et 77 et 79 et 82 et 84 et 85 et 88 et 90 et 95 et 97 et 10 0 et 10 8 et 11 5 et 12 8 et 13 2 h et er oh el ix g lo bu lo sa 10 7 61 11 2 16 8 15 3 64 77 66 52 26 68 54 11 9 10 7 10 8 19 3 13 8 86 13 3 12 4 66 61 14 8 g lo bi ge rin el lo id es u ltr am ic ru s 31 16 54 30 50 64 87 43 52 17 6 45 69 72 75 12 6 44 56 63 37 45 33 31 88 h et er oh el ix g la br an s 8 7 8 2 35 39 18 4 9 8 19 21 17 21 9 37 20 17 24 10 8 15 21 h et er oh el ix re us si 42 35 74 25 17 13 5 9 10 5 10 9 4 8 8 18 12 13 12 23 11 7 25 h et er oh el ix p ul ch ra 46 90 41 51 36 49 19 2 16 3 87 25 10 4 81 89 66 60 59 91 10 5 61 70 42 22 10 5 ar ch eo gl ob ig er in a cr et ac ea 6 3 0 1 4 10 2 7 2 0 7 1 0 4 6 7 1 2 5 7 8 13 6 ar ch eo gl ob ig er in a bl ow i 5 7 8 7 16 37 10 13 14 3 5 2 11 5 28 8 18 5 8 22 8 8 21 g lo bo tr un ca na v en tr ic os a 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 h et er oh el ix ca rin at a 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 g lo bo tr un ca na b ul lo id es 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 co st el la ge rin a pi llu la 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8 29 h ed be rg el la fl an dr in i 14 31 67 66 44 44 30 10 11 42 7 20 39 59 51 8 10 14 8 18 16 14 39 co nt us ot ru nc an a fo rn ic at a 2 0 0 18 6 1 0 0 0 2 7 3 2 1 5 6 0 2 5 4 3 3 1 si ga lia d efl ae ns is 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6 38 7 10 4 1 4 g lo bo tr un ca na li nn ei an a 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 m ar gi no tr un ca na si nu os a 0 0 0 3 3 1 1 0 1 2 3 6 0 5 3 3 0 1 0 6 4 11 3 h et er oh el ix n av ar ro en sis 2 9 8 5 10 17 13 6 5 6 11 5 3 8 9 8 0 6 2 6 5 0 3 g lo bt ru na ca na a rc a 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 g lo bo tr un ca ni ta ro se tt a 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 si ga lia sp . 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 h et er oh el ix m or em an i 8 7 8 2 9 3 7 6 8 1 4 5 11 8 8 5 3 2 5 10 0 0 4 g lo bo tr un ca ni ta in sig ni s 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 g lo bo tr un ca na m ar ie i 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 g lo bo tr un ca na ca lic ifo rm is 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ps eu do gl ob ul in a au st in an a 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 2 m ar gi no tr un ca na m ar gi na ta 1 0 3 3 10 6 0 1 1 1 2 1 0 6 9 7 7 14 4 4 4 1 1 d ic ar in el la co nc av at a 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 1 0 0 0 0 0 0 0 h ed be rg el la s im pl ex 0 0 3 4 22 9 6 0 1 5 0 3 5 8 17 7 2 2 0 10 2 1 6 m ar gi no tr un ca na u nd ul at a 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 2 0 0 0 3 2 3 0 ve nt ila br el la g la br at a 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 m ar gi no tr un ca na co ro na ta 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 1 0 0 0 1 0 1 1 g lo bo tr un ca ni ta st ua rt ifo rm is 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ve nt ila br el la e gg er i 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 g lo bo tr un ca na o rie nt al is 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 g lo bo tr un ca ni ta e le va ta 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ps eu do te xt ul ar ia n ut ta lli 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 co nt us ot ru nc an a pa te lli fo rm is 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 h et er oh el ix st ria ta 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 g lo bo tr un ca ni ta su bs pi no sa 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ve nt ila br el la a lp in a 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 m ar gi no tr un ca na ps eu do lin ne ia na 1 0 0 0 2 2 2 0 1 8 1 1 1 2 2 4 3 2 3 4 1 2 0 m ar gi no tr un ca na ta rfa ye ns is 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 3 2 1 0 m ar gi no tr un ca na re nz i 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 d ic ar in el la a sy m et ric a 0 0 0 0 0 0 0 0 0 0 1 0 1 1 2 0 1 0 0 3 0 1 0 m ar gi no tr un ca na sc hn ee ga ns i 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 si ga lia ca rp at ic a 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 m ar gi no tr un ca na pa ra co nc av at a 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6 0 4 1 1 1 0 0 to ta l 27 4 26 6 38 6 38 6 41 7 35 9 45 0 32 8 25 4 31 3 29 5 28 2 37 5 38 5 45 4 42 5 36 8 37 6 31 5 38 4 22 0 20 4 50 7 elamri et al.: santonian planktonic foraminiferal biostratigraphy of the northern tunisia geologia croatica 115 ta bl e 1: c on tin ua tio n sa m pl e no . et 13 4 et 13 9 et 14 1 et 14 5 et 14 6 et 14 7 et 14 8 et 14 9 et 15 0 et 15 1 et 15 2 et 15 5 et 15 6 et 15 7 et 15 8 et 15 9 et 16 0 et 16 1 et 16 2 et 16 3 et 16 4 et 16 6 h et er oh el ix g lo bu lo sa 76 13 1 86 35 10 5 17 1 84 70 12 9 27 83 46 24 28 75 50 58 98 88 42 67 56 g lo bi ge rin el lo id es u ltr am ic ru s 38 39 46 36 30 65 47 61 55 64 58 56 67 59 58 52 51 50 52 77 72 56 h et er oh el ix g la br an s 14 17 28 56 65 62 81 30 20 84 51 55 60 54 54 74 51 38 52 55 78 46 h et er oh el ix re us si 12 15 12 16 12 21 31 16 16 14 30 65 45 50 72 36 57 53 48 7 23 18 h et er oh el ix p ul ch ra 40 75 10 5 31 65 78 29 72 10 9 29 37 53 44 42 29 29 16 13 17 7 7 12 ar ch eo gl ob ig er in a cr et ac ea 7 9 2 0 8 12 23 13 2 3 12 26 18 9 17 14 17 17 10 1 9 10 ar ch eo gl ob ig er in a bl ow i 6 7 12 0 7 22 17 8 13 3 20 16 16 17 30 52 19 26 35 3 7 7 g lo bo tr un ca na v en tr ic os a 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 7 h et er oh el ix ca rin at a 0 0 0 0 0 0 0 0 0 0 0 5 36 38 19 43 26 24 16 16 13 5 g lo bo tr un ca na b ul lo id es 0 0 0 0 0 0 0 0 0 0 0 7 7 11 8 2 2 5 3 3 4 5 co st el la ge rin a pi llu la 6 21 13 2 12 10 1 0 2 4 13 16 4 0 7 15 18 16 20 1 0 5 h ed be rg el la fl an dr in i 17 12 27 16 16 30 32 20 33 22 28 38 30 25 29 36 7 21 33 3 6 4 co nt us ot ru nc an a fo rn ic at a 2 5 2 5 4 7 5 2 1 7 0 5 3 7 2 3 2 1 4 14 3 3 si ga lia d efl ae ns is 3 4 4 2 16 9 36 22 11 11 9 20 11 15 1 2 6 5 3 5 6 3 g lo bo tr un ca na li nn ei an a 0 0 0 0 0 0 0 0 0 0 0 6 6 7 3 2 3 7 2 16 4 3 m ar gi no tr un ca na si nu os a 3 9 8 17 15 11 6 6 2 9 5 0 2 1 0 3 3 5 10 8 1 3 h et er oh el ix n av ar ro en sis 7 4 5 5 4 21 13 4 4 4 2 9 14 5 9 5 5 4 4 6 3 2 g lo bt ru na ca na a rc a 0 0 0 0 0 0 0 0 0 0 0 9 5 6 6 5 1 2 11 11 2 2 g lo bo tr un ca ni ta ro se tt a 0 0 0 0 0 0 0 0 0 0 0 4 3 1 0 0 1 0 2 17 1 2 si ga lia sp . 0 0 0 0 0 0 0 0 0 0 0 0 16 2 1 4 0 1 0 1 0 2 h et er oh el ix m or em an i 5 10 1 0 5 4 1 4 2 1 0 8 0 0 1 5 9 10 6 1 0 1 g lo bo tr un ca ni ta in sig ni s 0 0 0 0 0 0 0 0 0 0 0 2 1 0 0 0 0 0 1 1 2 1 g lo bo tr un ca na m ar ie i 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1 1 1 0 1 0 0 1 g lo bo tr un ca na ca lic ifo rm is 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 1 ps eu do gl ob ul in a au st in an a 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 m ar gi no tr un ca na m ar gi na ta 5 4 1 28 9 11 17 17 5 10 2 1 0 0 0 0 0 1 3 1 4 0 d ic ar in el la co nc av at a 0 2 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 h ed be rg el la s im pl ex 2 0 3 3 2 3 0 3 1 3 1 0 4 2 0 6 1 2 0 0 0 0 m ar gi no tr un ca na u nd ul at a 4 1 1 2 2 2 1 1 0 1 1 0 0 0 0 0 0 0 0 0 0 0 ve nt ila br el la g la br at a 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 m ar gi no tr un ca na co ro na ta 1 0 0 2 1 1 0 0 1 1 3 1 0 0 0 0 0 0 0 0 0 0 g lo bo tr un ca ni ta st ua rt ifo rm is 0 0 0 0 0 0 0 0 0 0 0 3 1 1 0 0 0 0 3 0 1 0 ve nt ila br el la e gg er i 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 g lo bo tr un ca na o rie nt al is 0 0 0 0 0 0 0 0 0 0 0 7 7 1 0 2 0 5 4 4 2 0 g lo bo tr un ca ni ta e le va ta 0 0 0 0 0 0 0 0 0 0 0 4 0 0 0 0 1 1 2 4 0 0 ps eu do te xt ul ar ia n ut ta lli 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 1 1 2 5 0 0 0 co nt us ot ru nc an a pa te lli fo rm is 0 0 0 0 0 0 0 0 0 0 0 0 2 1 0 0 0 0 1 0 0 0 h et er oh el ix st ria ta 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 g lo bo tr un ca ni ta su bs pi no sa 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 2 0 1 1 0 0 ve nt ila br el la a lp in a 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 m ar gi no tr un ca na ps eu do lin ne ia na 6 8 8 19 6 3 1 6 3 5 12 0 0 0 0 0 0 0 0 0 0 0 m ar gi no tr un ca na ta rfa ye ns is 2 0 0 2 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 m ar gi no tr un ca na re nz i 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 d ic ar in el la a sy m et ric a 5 4 2 0 6 3 0 2 3 0 0 0 0 0 0 0 0 0 0 0 0 0 m ar gi no tr un ca na sc hn ee ga ns i 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 si ga lia ca rp at ic a 0 0 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 0 0 0 m ar gi no tr un ca na pa ra co nc av at a 1 0 0 3 1 0 0 3 0 1 0 0 0 0 0 0 0 0 0 0 0 0 to ta l 26 2 37 7 36 6 28 1 39 1 54 6 42 5 36 1 41 2 30 3 37 3 46 5 42 6 38 3 42 2 44 9 35 8 40 8 43 7 30 7 31 5 25 5 geologia croatica 67/2geologia croatica 116 ples were disaggregated were soaked in dilute hydrogen peroxide (h2o2), washed through a 63 µm sieve, and then dried. population counts are based on random splits of 300-500 specimens in the size fraction larger than 63 µm. all specimens were picked, identified and mounted on micro slides for permanent record. results of the quantitative analyses for the santonian succession and their boundaries at the ettout section and the santonian/ campanian boundary at jebel ennahli section are listed in tables 1 and 2 respecti vely. the most important foraminiferal specimens were digitally imaged under the phillips xl30 scanning electron microscope (sem) in the laboratories of the egyptian mineral resources authority (e.m.r.a.), having been sputtering coated for 8 min with gold at 20–30 ma°. in addition, several thin sections were prepared of indurated carbonate samples to assist in microfacies analysis and foraminiferal species determination. 3. lithostratigraphy the present study deals mainly with the kef formation (fournié, 1978) which overlies the bahloul formation and underlies the abiod formation. the age of the kef formation is late turonian to early campanian (robaszynski et al.; 2000; robaszynski & mzoughi 2010). it consists mainly of marl and limestone deposited in a pelagic or hemi-pelagic ramp setting. it is rich in inoceramids, e.g., endocostea ghadamensis (troger & röhlich) and in foraminifera, including globotruncana and globo­ truncanita representatives of campanian age (burollet, 1956; salaj, 1980; bellier, 1983; rami et al., 1997; robaszynski et al., 2000). at the ettout section, the lower part of the kef formation (fournié, 1978) is composed of marl with fossiliferous limestone and small pelecypods (nucula sp.). the frequency of these limestone interbeds increases towards the middle part (salaj, 1980; bellier, 1983; matmati et al., 1991; rami et al., 1997; elamri & zaghbib-tur ki, 2005). the middle portion of the kef formation contains the inoceramid bivalve platyceramus cycloides (wegner) and ammonite texanites texanus texanus (romer). towards, the upper parts of the kef formation, limestone beds are less frequent with very scarce macrofossils represented only by the echinoid species pleisaster peini (coquand) in the ettout section, followed by the predominantly white limestones of the abiod formation (bu rollet, 1956). a similar succession is observed at the jebel ennahli section with an observed lack of megafossils in the whole measured section, suggesting that these variations in macrofaunal assemblages may be environmentally controlled (fig. 2). 4. biostratigraphy the biostratigraphy of the upper coniacian – lower campanian succession in the study area is constructed with some modification based on the heterohelicidae planktonic foraminiferal zonal scheme of nederbragt (1990) and the scheme of robaszynski et al., (2000) for trochospiral forms. four tethyan trochospiral forms and three heterohe­ licidae planktonic foraminiferal zones are identified in this study, based on the lowest and highest occurrence, (los, hos) of the marker species. the biostratigraphic ranges of the identified planktonic foraminiferal species are given in figs. 3 and 4. the most important planktonic foraminiferal taxa are illustrated in plate 1. the established planktonic fotable 2: relative percent abundances around the santonian / campanian at jebel ennahli section, calculated for the > 63 µm fraction on 300-500 specimens. constusotruncana fornicata 20 12 50 5 31 12 60 75 30 marginotruncana undulata 5 11 0 3 5 0 0 0 0 marginotruncana sigali 1 0 4 1 0 0 0 0 0 heterohelix navarroensis 1 23 30 12 20 30 15 0 0 ventilabrella decoratissima 0 2 30 14 10 0 0 12 0 marginotruncana schneegansi 0 1 0 0 0 0 0 0 0 ventilabrella eggeri 0 1 1 14 50 6 0 0 0 globotruncana arca 0 0 0 0 15 2 0 0 1 globotruncana linneiana 0 0 0 0 7 18 15 0 25 globotruncana orientalis 0 0 0 0 6 24 14 6 14 planoglobulina manuelenisis 0 0 0 0 10 0 0 0 0 ventilabrella glabrata 0 0 0 0 0 12 0 0 0 heterohelix carinata 0 0 0 0 0 36 6 0 62 globotruncanita elevata 0 0 0 0 5 12 27 45 20 pseudotextularia nuttalli 0 0 0 0 0 2 35 4 35 globotruncana bulloides 0 0 0 0 0 0 6 5 16 globotruncana mariei 0 0 0 0 0 0 0 20 30 total 379 353 600 348 535 345 386 413 541 elamri et al.: santonian planktonic foraminiferal biostratigraphy of the northern tunisia geologia croatica 117 figure 3: lithology of the coniacian – campanian at jebel ettout section, with sample positions, range of planktonic foraminifera, and biostratigraphic zone; for symbol key see fig. 2. raminiferal bioevents and biozones arranged from older to younger are described below. 4.1. globotruncanidae biozones 4.1.1. dicarinella primitiva zone definition: this zone covers the interval from the lo of dicarinella primitiva to the lo of dicarinella concavata. author: caron (1978). age: late turonian-early coniacian. the present study deals only with the upper part of this zone. assemblage: the globotruncanidae are predomi nan t ly recorded in this zone represented by dicarinella imbri­ ca ta, marginotruncana paraconcavata, m. schneegansi, m. sigali, m. renzi, m. coronata, m. undulata, m. pseudo lin neia­ na in addition to the less common occurrence of witheinella paradubia, witheinella brittonensis and preaglobo trun cana gibba. for the complete assemblage see figs. 3 & 4. geologia croatica 67/2geologia croatica 118 figure 4: lithology of the coniacian – campanian at jebel ennahli section, with sample positions, range of planktonic foraminifera, and biostratigra phic zone; for symbol key see fig. 2. dicarinella spp. the zone is similar to that of the underlying dicarinella primitiva zone with the extinction of mar­ ginotruncana marianosi (figs. 3 and 4). remarks: the lo of dicarinella concavata is dated as late turonian (premoli silva & verga, 2004; ardestani et al., 2011), while other authors attributed it to the late coniacian (sigal, 1955; bellier, 1983; roba s zynski et al., 1984; caron, 1985; rami et al., 1997; robaszynski, 1998; robaszynski & caron, 1995; premoli silva & sliter, 1999; özkan-altiner & özcan, 1999; robaszynski et al., 2000; sa ri, 2009; farouk and faris, 2012; figs 3 & 4). the present di­ carinella concavata zone is approximately equivalent to the upper part of the dicarinella concavata zone of gradstein et al. (2012) and haq (2014), and coincides with the late coniacian cc14 nannofossil zone (farouk & faris, 2012). 4.1.3 dicarinella asymetrica zone definition: total range zone of the nominated taxon. age: santonian remarks: the stratigraphic range of dicarinella prim­ itiva differs from the two studied sections. the ho of di­ carinella primitiva at the ettout section is placed at the c/s boundary directly below the lo of dicarinella asymet­ rica. at jebel ennahli it is placed below the lo of di­ carinella concavata within the dicarinella primitiva zone (figs. 3 & 4). this zone is attributed by different authors to the early coniacian (e.g., wonders, 1980; caron, 1985; rami, 1998; abdel-kireem et al., 1995; elamri & zaghbib-turki, 2005), while it is dated as late turonian by other authors (premoli-silva & sliter, 1999). this biozone is considered to be of late turonian-early coniacian age in the tunisian sections (nederbraght, 1991). 4.1.2. dicarinella concavata zone definition: this zone covers the interval from the lo of dicarinella concavata to the lo of dicarinella asymetrica.. author: sigal (1955). age: late coniacian assemblage: in this interval the assemblages are highly abundant and contain well preserved marginotruncana and elamri et al.: santonian planktonic foraminiferal biostratigraphy of the northern tunisia geologia croatica 119 author: postuma (1971) assemblage: this biozone in both sections is characterized by the coexistence of predominant planktonic foraminiferal species belonging to the dicarinella and marginotrun­ cana genera. the marginotruncanids diminish in abundance and size toward the top of the dicarinella asymetrica zone. in this zone, the lo of the genus sigalia was observed in addition to ventilbrella decoratissima, costellagerina pil­ figure 5: comparison of different marker species distribution across the santonian / campanian boundary in tunisia. figure 6: bioevents observed from the coniacian to campanian and proposed planktonic foraminiferal zones. geologia croatica 67/2geologia croatica 120 ula, contusotruncana patelliformis and globotruncana man­ aurensis; for the complete assemblage see figs. 3 and 4. remarks: the lo of dicarinella asymetrica is more reliable for indicating the c/s boundary (e.g., melinte & lamolda, 2002; gradstein et al., 2012). in tunisian sections, according to robaszynski et al., (2000), the lo of dicarinella asymetrica indicates the lowest santonian and occurs within the calcareous nannofossil cc15 zone and is placed slightly below the lo of platyceramus cycloides (figs 3 and 4). at the ettout section, the lo of dicarinella asymetrica is observed at ~7m below the lo of platycera­ mus cycloides. 4.1.4. globotruncanita elevata/globotruncana arca zone definition: partial range zone from the ho of d. asy­ metrica to the lo of globotruncana ventricosa. author: modified after dalbiez (1955). age: early-middle campanian assemblage: planktonic foraminiferal abundance is gene rally high and preservation is usually good. common species include hedbergella flandrini, globigerinelloides ultra­ micrus, archaeoglobigerina blowi, a. creta cea, contuso­ truncana fornicata especially in the ennahli section. rare species include hedbergella simplex, globotruncana lin nei­ ana, costellagerina pilula, marginotruncana sinusoa and m. un dulata are also recorded (figs 6 & 7). remarks: the base of the campanian is placed before the ho of dicarinella asymetrica (considered to be a reliable bioevent to define the base of the campanian), (petriz zo, 2000; wagreich et al. 2010). it is easily recognizable and widely distributed in different palaeolatitudes. in the tunisian sections, the ho of d. asymetrica occurs at the santonian/ campanian boundary (e.g., rami, 1998; robaszynski et al. 2000; fig. 5). at the santonian-campanian transition, many events are observed 1) the extinction of sigalia, dicarinella and whiteinella; 2) the marginotruncanids suffered a gradual extinction; 3) an increase in the figure 7: relative abundance of the planktonic foraminiferal species correlates to the lithology and biozones at jebel ettout section; for symbol key see fig. 2. elamri et al.: santonian planktonic foraminiferal biostratigraphy of the northern tunisia geologia croatica 121 relative abundance of flat biserial and multiserial heterohelicids (ventilabrella and planoglobulina); 4) an increase in the relative abundance of globotruncana and globotruncanita genera (figs. 7 & 8). the lo of globotruncanita elevate and g. arca occurs slightly before the ho of d. asyme tri­ ca marker of the base of the campanian stage (robazsynski et al., 2000; figs 5 and 6). according to wagreich et al. (2010), the base of the campanian is placed after the fo of globotruncanita elevata as recorded in tunisian sections. the upper part of the globotruncanita elevata zone is defined by the lo of globotruncana ventricosa. actually, this event is problematic as it shows considerable variation in the stratigraphic ranges between different latitudes (pe trizzo, 2000; farouk & faris, 2012). on the northwestern australian margin, globotruncana ventricosa ranges down into at least the santonian dicarinella asymetri ca zone, and cannot be used to mark the upper boundary of the g. el­ evata zone. the lo of g. ventricosa occurs in the middle campanian in tethyan zonations and also in the present stu dy (e.g., caron, 1985; robaszynski & caron, 1995; robaszynski et al., 2000; mancini & puckett, 2005; farouk & faris, 2012). 4.2. heterohelicid biozones 4.2.1. pseudotextularia nuttalli zone definition: interval from the lo of pseudotextularia nuttalli to the lo of sigalia carpatica. age: coniacian – early santonian. author: nederbraght (1990) assemblage: this interval is marked by a high diversity and abundance of heterohelicid foraminifera with good preservation (e.g., heterohelix reussi, h. globulosa, h. glabrans, h. sphenoides, h. moremani, h. pulchra and h. navarroensis). remarks: the lo of pseudotextularia nuttalli is placed within the lowermost coniacian by a sporadic occurrence (e.g., nederbragt, 1990; rami, 1998; lamolda et al., 2007). according to nederbragt (1990), the pseu­ dotextularia nuttalli zone is attributed to the chronostratigraphic interval from the coniacian to the santonian. in the present study, it is attributed to the coniacian – early santonian (fig. 6). 4.2.2. sigalia carpatica zone definition: interval from the lo of sigalia carpatica to the lo of ventilabrella eggeri. age: late santonian author: salaj & samuel (1966) assemblage: this interval is marked by an abundance of heterohelicids with good preservation (e.g. heterohelix reussi, h. globulosa, h. glabrans, h. sphenoides, h. more­ mani, h. pulchra, h. navarroensis, sigalia deflaensis, and ventilabrella decoratissima). rare large biserial and flat multiserial heterohelicid morphogroup including pseudotextu­ laria, planoglobulina, sigalia and ventilabrella are observed in the middle and upper parts of the santonian deposits. they do not exceed 10% at the ettout section, increase to around 16% of the total assemblages at the ennahli section. remarks: in the tunisian sections, there is an absence of flat heterohelicid species, with limbate sutures such as si­ galia deflaensis, s. carpatica. large multiserial heterohelicids ventilabrella decoratissima are observed near the base of the santonian which is also different (e.g., nederbragt, 1991; rami et al., 1997; el amri & zaghbibturki, 2005 and the present study). robaszynski & caron (1995) mentioned that sigalia carpatica appears before the lo of sigalia deflaensis. in the present study, the figure 8: relative abundance of the planktonic foraminiferal across the santonian campanian boundary correlates to the lithology and biozones at the ennahli section. geologia croatica 67/2geologia croatica 122 lo of sigalia deflaensis appears earlier than sigalia carpat­ ica at the ettout section while at the jebel ennahli section it appears together with sigalia carpatica and ventilabrella decoratissima. the lo of flat heterohelicids with limbate sutures such as sigalia carpatica and ventilabrella decora­ tissima is recorded above the lo of dicarinella asymetrica. the lo of sigalia carpatica is used as a second marker for the coniacian/santonian boundary in the proposed gssp at the olazagutia section (lamolda, 2013). this event is problematic as it shows considerable variation in age due to it’s rarity and sporadic presence in tunisian sections (rami et al., 1997), although it is easily recognized by its flat heterohelicids with limbate sutures. many authors suggested the lo of dicarinella asymetrica and sigalia carpatica cooccur together (salaj, 1980; robaszynski and caron, 1995). other authors noticed that the lo of sigalia carpat­ ica does not occur simultaneously with the lo of dicarinella asymetri ca (e.g., nederbragt, 1991; rami et al., 1997; robaszynski et al., 2000; el amri & zaghbib-turki, 2005). in the pre sent study, the lo of this taxon occurs higher in the upper santonian succession and does not coincide with the lo of dicarinella asymetrica (fig. 6). at the jebel ennahli section, the lo of sigalia deflaensis occurs simultaneously with the lo of sigalia carpatica and venti­ labrella decoratissima, while in the ettout section, the lo of sigalia carpatica appears higher, after the lo of sigalia deflaensis. 4.2.3. ventilabrella eggeri/planoglobulina manuelenisis concurrent range zone definition: interval from the ho of sigalia carpatica to the lo of gublerina acuta age: early campanian author: modified after nederbragt (1991) assemblage: ventilabrella aplina, v. eggeri, v. glabra ta, planoglobulina manuelensis, and heterohelix carinata are common in this zone, for the complete assemblage see figs. 3 & 4. remarks: the lo of ventilabrella eggeri was used as a good marker for the santonian and campanian boundary (nederbragt, 1991; robaszynski & caron, 1995). it is associated with the ho of sigalia spp. and di­ carinella spp, which marks the base of the campanian. the lo of planoglobulina manuelensis appears together with ventilabrella eggeri simultaneously at the base of the globotruncanita elevata zone (figs. 3 and 4). however, arz (1996) adopts the lo of ventilabrella eggeri to mark the terminal santonian as recorded at the jebel ettout section, while at the ennahli section, it is recorded near the base of the campanian (figs. 3 & 4). nederbragt (1991) gave a late santonian – early campanian age for the v. eggeri zone. in the present study, this zone is approximately equivalent to the lower part of the globotruncanita elevata / globotrun­ cana arca zone. in both studied sections, only the lower part of the ventilabrella eggeri/planoglobulina manuelenisis zone was investigated. 5. planktonic foraminiferal relative abundances the distribution of planktonic foraminifers depends on sea surface water temperature and density. diverse geometric tests were used to separate and distinguish the specimens found in particular depth ranges within the water column (ardestani et al., 2013). three groups of planktonic foraminifera were identified on the basis of different depth zones (petrizzo, 2002; ardestani et al., 2013): shallow surface water forms (swf), intermediate water foraminifera (iwf) and deep water forms (dwf) as follows: surface water foraminifera: (swf): this group is represented by simple morphotypes (heterohelix globulosa, h. moremani, and h. reussi) or the non-keeled trochospiral morphotype group (whiteinella paradubia and w. brittonensis). intermediate water foraminifera (iwf): this group is represented by preaglobotruncana gibba, heterohelix pul­ chra, h. glabrans, h. carinata, hedbergella delrieonsis, hd. simplex, globigerinelloides ultramicrus, archaeoglobige­ rina blowi and ar. cretacea. deep water foraminifera (dwf): this group consists of ornamented and trochospiral forms of planktonic foraplate: 1-3 dicarinella asymetrica; sample et82. 4-6 dicarinella concavata; sample et69. 7 hedbergella simplex; sample en64. 8 whiteinella paradubia; sample et160. 9-10 marginotruncana tarfayaensis; sample en59. 11-12 marginotruncana pseudolinneiana; sample en64. 13-15 marginotruncana sinuosa, sample en64. 16-18 globotruncanita elevata; sample et160. 19-20 contusotruncana fornicata; sample et81. 21 heterohelix pulchra; sample en66. 22-23 heterohelix striata; sample en65. 24-25 pseudotextularia nuttalli; sample en56. 26 sigalia carpatica; sample et154. 27 planoglobulina manuelensis; sample en66. 28 ventilabrella eggeri; sample en66. (en=ennahli section; et= jebel ettout section) scale bar: 100µm elamri et al.: santonian planktonic foraminiferal biostratigraphy of the northern tunisia geologia croatica 123 geologia croatica 67/2geologia croatica 124 minifera including pseudotextularia nuttalli, marginotrun­ cana renzi, m. schneegansi, m. undulata, m. paraconcavata, m. coronata, m. tarfayaensis, m. sinusoa, m. marginata, m. pseudolinneiana, contusotruncana fornicata, c. patelli­ formis, globotruncanita elevata, gt. insignis, globotrun­ cana arca, g. orientalis, g. mariei, g. bulloides, sigalia car­ patica, ventilabrella decoratissima, v. eggeri, v. glabrata, v. alpina, planoglobulina manuelensis. dicarinella conca­ vata, d. primitiva and d. asymetrica. the planktonic foraminiferal assemblages are dominated by the small heterohelicid representatives mainly h. globu­ losa during the coniacian of the dicarinella primitiva zone (fig. 7). other species of the heterohelicidae group are less abundant and represented by heterohelix navarroensis and h. moremani. thus, at the ettout section, the relative abundance of this species reaches 60 % of the total assemblage (fig. 7). the heterohelix spp. are associated with other cosmopolitan species belonging to hedbergella, globigerinelloides and ar­ chaeoglobigerina genera that were considered as subsurface water dwellers. their relative abundance does not exceed 30%. at the coniacian / santonian boundary, a decrease in the abundance of the simple morphotype heterohelix globu­ losa from 60 % to 20 % is followed by an increase in the abundance of keeled trochospiral morphogroup belonging to the genus marginotruncana. the latter is considered as the most abundant and the most diversified group (fig. 7). this turnover is related to an increase in water depth during the santonian. the relative abundance of the total planktonic foraminifera in the two studied sections reaches 20 % of the total assemblage (>100 µm size fraction). the dominance of the santonian assemblages by heterohelicids and unkeeled morphotypes such as representatives of globigerinelloi des, hedbergella and archaeoglobigerina and the presence of keeled trochospiral morphotypes belonging to dicari nel la, marginotruncana, globotruncanita and globotruncana genera, does not exceed 20 % of the planktonic foraminiferal assemblage. a major turnover in planktonic foraminifera occurred across the santonian/campanian (s/c) boundary associated with 1) the sharp extinction of dicarinella and sigalia; 2) the gradual extinction of marginotruncana; and 3) an increase in the relative abundance of globotruncanita and globotruncana genera. this turnover could be related to an improvement in their ability for better adaptation to a deeper habitat of the photic water column (figs. 7 & 8). 6. conclusion – fifty-fife planktonic foraminiferal taxa belonging to 17 he terohelicid and 38 trochospiral forms are identified with mo derate to good preservation and relatively high diversity. – these microfossil assemblages allowed subdivision of the studied sections based on two different zonation schemes (heterohelicidae and globotruncanidae) to produce a higher resolution biostratigraphy and better correlation between deep and shallower basins. – the base of the santonian is marked by the lo of di­ carinella asymetrica associated with a decrease of the simple morphotypes and increase of keeled trochospiral morphogroup indicating a deepening phase. – a major turnover in planktonic foraminifera occurred at the santonian-campanian transition. it is marked by the extinction of all dicarinella, whiteinella, sigalia and mar­ ginotruncana (except marginotruncana marginata and m. sinuosa. after the extinctions, extremely well-preserved and diverse assemblages of globotruncanita, globotruncana and large heterohelicids such as ventilabrella and planoglob­ ulina reflect a characteristic campanian planktonic foramini feral assemblage. acknowledgement the second author wishes to thank the alisa martek and vlasta ćosović for editorial support. references abdel-kireem, m.r., samir, a.m. & ibrahim, m.i. (1995): upper cretaceous planktonic foraminiferal zonation and correlation in the northern part of the western desert, egypt.– neues jahrbuch fur geologie und palaontologie abhandlungen, 198, 329–361. ardestani, m.s., vahidinia, m. & abbas sadeghi, a. (2013): paleoceanography and paleobiogeography patterns of the turoniancampanian foraminifers from the abderaz formation, north eastern iran.– open journal of geology, 3, 19–27. http://dx.doi.org/ 10.4236/ojg.2013.31003. ardestani, m.s., vahidinia, m. & youssef, m. (2011): biostratigraphy and foraminiferal bioevents of the abderaz formation (middle turonian-lower campanian) in kopeh-dagh sedimentary basin, northeastern iran.– egyptian journal palaeontology, 11, 1–16. arz, j.a. (1996): los foraminiferos planctonicos del campaniense y maastrichtiense: bioestratigrafia, cronoestratigrafia y eventos paleoecologicos.– unpublished ph.d. thèse. université de zaragoza, 419 p. arz, j.a. & molina, e. (2002): bioestratigrafía y cronoestratigrafía con foraminíferos planctónicos del campaniense superior y maastrichtiense de latitudes templadas y subtropicales (españa, francia y tunicia).– neues jahrbuch für geologie und paläontologie, monatshefte, 224, 161–195. bellier, j.p. (1983): foraminifères planctoniques du crétacé de tunisie septentrionale. systématique, biozonation, utilisation stratigraphique de l‘albien au maastrichtien.– thèse doc. es sciences, univ. pierre et marie curie, paris, 250 p. bey, s., kuss, j., silva, i.p., negra, m.h. & gardin, s. (2012): fault-controlled stratigraphy of the late cretaceous abiod formation at ain medheker (northeast tunisia).– cretaceous research, 34, 10–25. bralower, t.j., leckie, r.m. & sliter, w. (1995): an integrated cretaceous microfossil biostratigraphy.– in: berggren, w.a., kent, d.v., aubry, m.-p. & hardenbol, j. (eds.): geochrono logy, time scales and global stratigraphic correlation. sepm special publication, vol. 54, 65–79. burollet, p.f. (1956): contribution à l’étude stratigraphique de la tunisie central.– ann min geol tunis, 18, 1–350. caron, m. (1985): cretaceous planktonic foraminifera.– in: bolli, h.m., saunders j. & perch-nielsen, k. (eds): plankton stratigraphy. cambridge univ. press. cambridge, 17–86. elamri et al.: santonian planktonic foraminiferal biostratigraphy of the northern tunisia geologia croatica 125 cobban, w.a., dyman, t.s. & porter, k.w. (2005): paleontolo gy and stratigraphy of upper coniaciane middle santonian ammonite zones and application to erosion surfaces and marine transgressive strata in montana and alberta.– cretaceous research, 26, 429–449. coward, m.p. & ries, a.c. (2003): tectonic development of north african basins.– in: arthur, t.j., macgregor, d.s. & cameron, n.r. (eds.): petroleum geology of africa: new themes and developing technologies. geol. soc. lond. spec. pub., 207, 61–83. dalbiez, f. (1955): the genus globotruncana in tunisia.– micropaleontology, 1, 161–171. dalbiez, f. (1956): etude sommaire des microfaunes de la région du kef.– notice de la carte géologique de tunisie, feuille 44, le kef au 1/50000, publ. ser. géol. tunisie, 35–37. el amri, z. & zaghbib-turki, d. (2005): caractérisation biostratigraphique du passage coniacien/santonien dans les régions d’ellès et el kef (tunisie septentrionale).– journal of iberian geology, 31/1, 99–111. farouk, s. & faris, m. (2012): late cretaceous calcareous nannofossil and planktonic foraminiferal bioevents of the shallow-marine carbonate platform in the mitla pass, west central sinai, egypt.– cretaceous research, 33, 50–65. fournié, d. (1978): nomenclature lithostratigraphique des séries du crétacé supérieur au tertiaire de la tunisie.– bull. cent. rech. expl. prod. elf-aquitaine, 2/1, 97–148. gale, a.s., kennedy, j.w., lees, j.a., petrizzo, m.r. & wala szczyk, i. (2007): an integrated study (inoceramid bivalves, ammonites, calcareous nannofossils, planktonic foraminifera, stable carbon isotopes) of the ten mile creek section, lancaster, dallas county, north texas, a candidate global boundary stratotype section and point for the base of the santonian stage.– acta geologica polonica, 57, 113–160. gradstein, f.m., ogg, j.g., schmitz, m. & ogg, g. (2012): the geologic time scale 2012.– elsevier, 144 p. haq, b.u. (2014): cretaceous eustasy revisited.global and planetary change, 113, 44–58. lamolda, m.a. (2013): the base of the santonian stage in the „cantera de margas”, olazagutia, n spain.– in: garcia-hidalgo, j.f., gil-gil, j., barroso-barcenilla, f., lopez olmedo, f.y & diaz de neira, j.a. (eds.): v congreso des cretacico en espana, 32–35. lamolda, m.a., gallemí, j., ion j., lópez, g., martínez, r., melinte m.c., paul, c. r.c., peryt d. & pons, j.m. (2013): the global boundary stratotype and section point (gssp) for the base of the santonain stage cantera de margas olazagutia northern spain.– 9th international symposium on the cretaceous sy stem, p. 52. lamolda, m.a., peryt, d. & ion, j. (2007): planktonic foraminiferal bioevents in the coniacian/santonian boundary interval at olazagutia, navarra province, spain.– cretaceous research, 28/1, 18–29. li, l. & keller, g. (1998): maastrichtian climate, productivity and faunal turnovers in planktic foraminifera in south atlantic dsdp sites 525a and 21.– marine micropaleontology, 33, 55–86. mancini, e.a. & puckett, t.m. (2005): jurassic and cretaceous transgressive-regressive (t-r) cycles, northern gulf of mexico, usa.– stratigraphy, 2/1, 31–48. matmati, m.f., maamouri, a.l., ben haj ali, m., salaj, j. & donze, p. (1991): etude stratigraphique et micropaléontolo gique dans le crétacé supérieur et le paléocène de la chaîne faid chaâbet el attaris (axe n-s, tunisie centre-est).– notes serv. géol. tunisie, 57, 35–46. melinte, m.c. & lamolda, m.a. (2002): calcareous nannofossils around the coniacian/santonian boundary interval in the olazagutia section (n. spain).– in: wagreich, m. (ed.): aspects of cretaceous stratigraphy and palaeobiogeography. österreichische akade mie der wissenschaften, schriftenreihe der erdwissenschaftlichen kommissionen, 15, 351–364. nederbragt, a.j. (1991): late cretaceous biostratigraphy and development of heterohalicidae (planktic foraminifera) in biostratigraphy and paleoceanographic potential of cretaceous planktic foraminifera heterohelicidae.– centrale huisdruk kerj vrije uni ver siteit amesterdam academisch proefschrift, 61–125. özkan-altiner, s. & özcan, e. (1999): upper cretaceous planktonic foraminiferal biostratigraphy from nw turkey: calibration of the stratigraphic ranges of larger benthonic foraminifera.– geological journal, 287–301. pervinquière, l. (1903): etude géologique de la tunisie centrale.– thèse es-sciences, univ. paris, de rudeval f. r. (édit.), paris, 360 p. pervinquière, l. (1907): etude de la paléontologie tunisienne: i céphalopodes des terrains secondaires. direction générale des travaux publics, carte géologique de la tunisie, de rudeval f. r. (édit.), 427 p., 27 pl. peryt, d. & lamolda, m.a. (2007): neoflabellinids (benthic foraminifers) from the upper coniacian and lower santonian at olazagutia, navarra province, spain; taxonomy and correlation potential.– cretaceous research. 28/1, 30–36. petrizzo, m.r. (2000): upper turonian-lower campanian planktonic foraminifera from southern mid-high latitudes (exmouth plateau, nw australia): biostratigraphy and taxonomic notes.– cretaceous research, 21, 479–505. petrizzo, m.r. (2002): palaeoceanographic and palaeoclimatic inferences from late cretaceous planktonic foraminiferal assemblages from the exmouth plateau (odp sites 762 and 763, eastern indian ocean).– marine micropaleontology, 45, 117–150. pini, s. (1971): carte géol. de la tunisie au 1/50000.– notice explicative de la feuille géologique d’ariana au 1/50 000, 13, 62 p. postuma, j.a. (1971): manual of planktonic foraminifera.– elsevier publ. comp., london, 420 p. premoli silva i. & sliter v.w. (1999): cretaceous paleoceanography: evidence from planktonic foraminiferal evolution.– geological society of america, special paper 332, 301–328. premoli silva, i. & verga, d. (2004): practical manual of cretaceous planktonic foraminifera. international school on planktonic foraminifera, 3° course: cretaceous.– in: verga, d. & rettori (eds.): universities of perugia and milan, tipografia pontefelicino, perugia (italy), 283 p. rami, a. (1998): précisions biostratigraphiques et milieu de dépôt des séries du crétacé supérieur de la tunisie centro-septentrionale.– thèse d'etat, fac. sc. de tunis, 243 p., 22 pl. rami, a., zaghbib-turki, d. & elouradi, h. (1997): biostratigraphie (foraminifères) et contrôle tectono-sédimentaire du crétacé supérieur dans la région de mejez el bab (tunisie septentrionale).– géol. méditerranéenne, 24/1–2, 101–123. robaszynski, f. & caron, m. (1995): foraminifères planctoniques du crétacé: commentaire de la zonation europe-méditerranée. – bull. soc. géol. france, 166 /6, 681–692. robaszynski, f., caron, m., gonzalez donozo, j.m., wonders, a.h. & europeen working group on planktonic foraminifera (1984): atlas of late cretaceous globotruncanids.– revue de micropaléontologie, 26/3–4, 145–305. robaszynski, f., gonzalez donozo, j.m., linares, d., ame dro, f., caron, m., dupuis, c., dhondt, a.v. & gartners, s. (2000): le crétacé supérieur de la région de kalaat senan, tunisie centrale. litho-biostratigraphie intégrée zones d’ammonites, de foraminifères planctonique et de nannofossiles du turonian supérieur au maastrichtien.– bull. centre rech. explor.– prod. elf aquitaine, 22, 359–490. robaszynski, f. & mzoughi, m. (2010). the abiod at ellès (tunisia): stratigraphies, campanian-maastrichtian boundary, correlageologia croatica 67/2geologia croatica 126 tion.– car nets de géologie/notebooks on geology. article 2010/04 (cg2010_a04). salaj, j. (1980): microbiostratigraphie du crétacé du paléogène de la tunisie septentrionale et orientale (hypostratotypes tunisiens).– inst. géol. dionyz stur bratislava, 238 p., 64 pl. sari, b. (2009): planktonic foraminiferal biostratigraphy of the coniacian-maastrichtian sequences of the beydag˘ları autochthon, wes tern taurides, turkey: thin-section zonation.– cretaceous research, 30, 1103–1132. wagreich, m., summesberger, h. & kroh, a. (2010): late santonian bioevents in the schattau section, gosau group of austria implications for the santonian–campanian boundary stratigraphy.– cretaceous research, 31, 181–191. http://dx.doi.org/10.1016/j. cretres.2009.10.003 wonders, a.a.h. (1980): middle and late cretaceous planktonic foraminifera of the western mediterranean area.– utrecht micropaleontol, b 24, 1–157. manuscript received december 02, 2013 revised manuscript accepted may 28, 2014 available online june 17, 2014 appendix list of species identified in this work, arranged alphabetically by genus with author attributions and dates. 1. archaeoglobigerina blowi pessagno, 1967 2. archaeoglobigerina cretacea d’orbigny, 1840 3. contusotruncana fornicata (plummer, 1931). 4. contusotruncana patelliformis (gandolfi,1955) 5. costellagerina pilula belford, 1960 6. dicarinella asymetrica (sigal, 1952) 7. dicarinella concavata (brotzen, 1934) 8. dicarinella imbricata (mornod, 1949) 9. dicarinella primitiva (dalbiez, 1955) 10. globotruncana arca (cushman, 1926) 11. globotruncana mariei banner & blow, 1960 12. globotruncana bulloides (vogler, 1941) 13. globotruncana caliciformis de lapparent, 1918 14. globotruncana linneiana (d’orbigny, 1839) 15. globotruncana manaurensis gandolfi, 1955 16. globotruncana orientalis el naggar, 1966 17. globotruncana rosetta (carsey, 1926) 18. globotruncana ventricosa white, 1928 19. globotruncanita elevata (brotzen, 1934) 20. globotruncanita insignis (gandolfi, 1955) 21. globotruncanita stuartiformis (dalbiez, 1955) 22. globigerinelloides ultramicra (subbotina, 1949) 23. hedbergella delrioensis (carsey, 1926) 24. hedbergella flandrini porthault, 1970 25. hedbergella simplex (morrow, 1934) 26. heterohelix glabrans (cushman, 1938) 27. heterohelix globulosa (eherenbeg, 1840) 28. heterohelix moremani (cushman, 1938) 29. heterohelix navarroensis loeblich, 1951 30. heterohelix pulchra (brotzen, 1936) 31. heterohelix reussi (cushman, 1938) 32. heterohelix sphenoides masters, 1976 33. heterohelix carinata (cushman, 1938) 34. marginotruncana coronata (bolli, 1945) 35. marginotruncana marginata (reuss, 1845) 36. marginotruncana marianosi (douglas, 1969) 37. marginotruncana paraconcavata porthault, 1970 38. marginotruncana pseudolinneiana pessagno, 1967 39. marginotruncana schneegansi (sigal, 1952) 40. marginotruncana sigali (reichel, 1949) 41. marginotruncana sinuosa porthault, 1970 42. marginotruncana tarfayaensis (lehmann, 1962) 43. marginotruncana undulata (lehmann, 1963) 44. praeglobotruncana gibba klaus, 1960 45. planoglobulina manuelensis (martin, 1972) 46. pseudoplanoglobulina austinana loeblich & tappan, 1987 47. pseudotextularia nuttalli (voorwijk, 1937) 48. sigalia carpatica salaj & samuel, 1963 49. sigalia deflaensis (sigal, 1952) 50. ventilabrella alpina de klasz, 1953 51. ventilabrella decoratissima (de klasz, 1953) 52. ventilabrella eggeri cushman, 1928 53. ventilabrella glabrata cushman, 1938 54. whiteinella brittonensis (loeblich & tappan, 1961) 55. whiteinella paradubia (sigal, 1952) 2023 | 76/2 | 57–72 | 11 figs. | 2 supplements. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the central paratethys disintegrated towards the end of the middle miocene, leaving in its wake the late miocene lake pannon (magyar et al., 1999; piller et al., 2007). the brackish lake pannon lost its marine life, and the largely endemic ostracod and molluscan fauna of the lake is well-known from its fossil record. upper miocene ostracods from the krško basin, se slovenia miha marinšek1, valentina hajek-tadesse2, marijan poljak3, tea kolar-jurkovšek1 and luka gale1,4 1 geological survey of slovenia, dimičeva ul. 14, 1000 ljubljana, slovenia; (miha.marinsek@geo-zs.si, tea.kolar-jurkovsek@geo-zs.si, luka.gale@geo-zs.si) 2 croatian geological survey, sachsova 2, 10 000 zagreb, croatia; (tadesse@hgi-cgs.hr) 3 zgornje gorenjce 27, 8333 semič; (marijanpoljak7@gmail.com) 4 university of ljubljana, faculty of natural sciences and engineering, department of geology, aškerčeva cesta 12, 1000 ljubljana, slovenia; (luka.gale@ntf.uni-lj.si) doi: 10.4154/gc.2023.07 abstract the purpose of this study was to identify the ostracod assemblage from a 43 m thick section of the bizeljsko formation, which constitutes the middle part of the upper miocene posavje group. the succession comprises sandstone, siltstone, and marlstone, deposited in a delta front environment. the determined ostracods belong to the families cyprididae, cytheridae, darwinulidae, and loxoconchidae. in total, 30 species were identified. additionally, 8 morphotypes were determined at the genus level. the most common genera are candona, hemicytheria, and cypri­ deis. the assemblage belongs to the caspiocypris labiata subzone from the upper pannonian. the ostracod assemblage from the krško basin is similar in species composition to pannonian ostracod assemblages from croatia and serbia. finally, the determined ostracod assemblage was compared to assemblages of the same age from the paratethys area. data presented here serve as an important contribution to the understanding of the distribution of ostracods in lake pannon as the last known scientific paper on miocene ostracods from slovenia was published in 1989 (stevanović & škerlj, 1989). a short article history: manuscript received january 10, 2023 revised manuscript accepted june 29, 2023 available online july 11, 2023 keywords: lake pannon, bizeljsko formation, pannonian, biostratigraphy, palaeoenvironment figure 1. palaeogeographic map of the central paratethys (pannonian age) with the approximate location of slovenia (sb: styrian basin; mzb: mura-zala basin) modified after kovac et al., 2017). research on the ostracod fauna is thus extremely important in determining the relative age, the palaeo ecological conditions, and the palaeogeographic connections bet ween individual sub-basins of lake pannon (krstić, 1972, 1973; sokač, 1981, 1989; jiři­ ček & riha, 1991; rundić, 1997; ter borgh et al., 2013). this paper presents the ostracod assemblage recovered from a 43 m thick succession of the upper miocene bizeljsko formation near the village of bizeljsko, situated on the ne hilly rim of the krško basin in se slovenia (figs. 1, 2). the succession is well exposed along a forest road, starting at coordinates lat: 45°59’49.10’’, lon: 15°41’01.23’’ (figs. 3, 4). the relative age of the studi ed section and palaeosalinity were determined, based on ostracods. mailto:miha.marinsek@geo-zs.si mailto:tea.kolar-jurkovsek@geo-zs.si mailto:luka.gale@geo-zs.si mailto:marijanpoljak7@gmail.com mailto:luka.gale@ntf.uni-lj.si g eo lo gi a c ro at ic a geologia croatica 76/258 description of ostracods from the krško basin and the bizeljsko section are given by vesel­lukić (2012) and vesel­lukić et al., (2013, 2014). there was also a masters thesis done on the studied section by marinšek (2020). 2. geological and stratigraphic setting slovenia is located in the western part of central paratethys, where the transtethyan corridor was theorised to be located in the badenian (bartol, 2009). sediments of the central paratethys in slovenia are predominantly found in the eastern part of the country and extend westwards towards central slovenia in a series of synclines that once formed interconnected basins (fig. 2). the ne part of slovenia was connected to the “styrian” and mura­zala basins (jelen & rifelj, 2002) and most of the se part was connected to the north croatian basin (jelen et al., 1992; pavelić, 2005). the structural development of eastern slovenia resulted in four tectono­stratigraphic units (ttu) (jelen et al., 1992). from north to south, these are: ttu a1, ttu a2, ttu b1, and ttu b2 (fig. 2). unit a1 covers the area north of the periadriatic fault zone, namely the northern karavanke, pohorje, and the pannonian plain of northeastern slovenia. unit a2 is a narrow area between figure 2. the present-day distribution of sediments and sedimentary rocks of the tectono-stratigraphic units of the central paratethys in eastern slovenia. bl balaton line, cnl celje-nadžkaniža line, ctz celje tectonic zone, dl donat line, mhz middle hungarian tectonic zone, pal periadriatic line, sf sava fault, šf, šoštanj fault, sb senovo basin, kb krško basin. for an explanation of the tectonostratigraphic units (a1, a2, b1, b2) see text. the star symbol marks the position of the sampled section. modified after jelen & rifelj (2002). figure 3. position of the studied area. the exact position of the section is shown by a dashed rectangle in figure 2b. the section starts at coordinates lat: 45°59’49.10’’, lon: 15°41’01.23’’. g eologia c roatica marinšek et al.: upper miocene ostracods from the krško basin, se slovenia 59 the periadriatic fault zone and the don tectonic zone, which includes the southern karavanke and haloze areas. unit b1 stretches from the julian alps to the sava tectonic zone and continues to the area of varaždin in croatia. unit b2 covers the entire south­eastern part of slovenia, including the krško basin and thus also the area of bizeljsko. after deposition of the neogene sediments, the area underwent compression, resulting in the formation of the sava folds, a w­e extending series of antiforms and synforms (placer, 1999a). the general facies succession of the miocene sediments in slovenia is composed of alternating marl/marlstone, sand/sandstone with cobblestone, and in some places, there are beds of lignite (pleničar, 1954; cigit, 1958; vončina, 1966; pleničar, 1968; premru & marinčić, 1971; kuščer, 1973; arsovski et al., 1975; mioč & žnidarčič, 1978; kaloper 1984; aničić & juriša 1985a, b; žnidarčič & mioč, 1987; marković & mioč, 1988; mioč & žnidarčič, 1989; djurasek, 1995; placer, 1999b; šram et al., 2015). in slovenia, the evolution of lake pannon is best recorded in the krško and senovo basins (fig. 2). panonnian calcareous marls conformably overlie sarmatian beds; which are overlain by “ostracod marls”. in some parts of the krško basin the pannonian lies unconformably on the sarmatian beds (poljak et al., 2016) the pannonian succession ends with quartz sand and marly-clayey intercalations with lignite on top. the entire neogene succession can be interpreted as a transition from marine to brackish and finally freshwater conditions (pavšič & horvat, 2009; ivančič, 2021). important fossil groups that have been investigated in the upper miocene sediments of eastern slovenia are ostracods (pierau, 1958; sokač, 1981; stevanović & škerlj, 1985, 1989; hajek­ tadesse, 2007; vesel­lukić, 2012; vesel­lukić et al., 2013, 2014; marinšek, 2020), and molluscs (mikuž, 2005, 2014; mikuž et al., 2015). the bizeljsko area corresponds to the northern limb of the krško synclinorium and is a part of the b2 ttu (placer, 1999a, b; poljak, 2017). the geological maps of the study area were produced by aničić & juriša (1985a, b), and more recently by poljak et al. (2017). a simplified geological map is shown in figure 5. the stratigraphic succession in the study area is summarized after poljak (2017) (fig. 6). the oldest deposits of the central paratethys in the research area belong to the badenian–sarmatian laško formation. it comprises shallow marine coralline algal­rich limestone, the “lithothamnium limestone”, and the deeper marine “laško marl”. the laško formation is, after another prominent unconformity, followed by marls and sands of the deltaic pannonian drnovo formation, which in its upper part passes into the bizeljsko formation. the latter comprises quartz sand, marl, and subordinate sandstone and gravel, deposited within a delta front environment. the uppermost pannonian raka formation almost entirely consists of quartz sand, which was also deposited in a deltaic environment. the drnovo, bizeljsko, and raka formations together comprise the posavje group, which represents the final remnants of the central paratethys. the youngest sediments in the area are represented by quaternary gravel (poljak, 2017). figure 4. field pictures of the studied section. a – bottom of the marl in the middle of the section (view towards the south).; b – a detailed picture of the marl section; c – transition from the marl to sand; d – sand section in the upper part of the outcrop (author: marina vesel-lukić, 2012) g eo lo gi a c ro at ic a geologia croatica 76/260 the bizeljsko formation is best exposed in the eastern krško basin, especially in the bizeljsko area. the formation was defined by poljak (2017). it was previously also researched by lapajne (1976), šikić et al. (1979), skaberne (1990), škerlj (1990), trajanova (2006), hajek­tadesse (2007), vesel­lukić et al. (2013, 2014); marinšek (2020) and poljak (2017). the formation consists mainly of marls and sands, which alternate over short distances. beds of sand locally show traces of slumping and/or contain rip-up clasts of marl. it reaches its thickest point (up to 800 m) in the wider bizeljsko area. the age was first determined based on bivalves (congeria croatica, c. rhomboidea, c. zagrabiensis, lymnocardium majeri, l. riegeli, paradacna abichi and paradacna okrugici, as well as ostracods (šikić et al., 1979; hajek­tadesse, 2007; poljak, 2017). poljak (2017) interpreted the succession as a delta front deposit based on individual layers of sand showing signs of synsedimentary slumping with frequent layers containing rip-up marl clasts. it represents the part of the lake pannon evolution where it began to shrink and transitioned locally from brackish to freshwater conditions. the bizeljsko formation is completely missing in the western part of the krško basin. instead, the upper pannonian deposits are represented there by a much thinner succession of marls and sandy marls of the drnovo formation (poljak, 2017). 3. material and methods the section of the bizeljsko formation was logged and sampled with a total stratigraphic length of 43 m (fig. 7). in total, 38 samples were collected and subsequently processed in the laboratory. individual samples weighed between 1 and 2 kg. each sample was quartered to a weight of 250g – 500g. samples were dissolved in a 5% hydrogen peroxide solution; samples that contained a large number of ostracod valves filled with sediment were put in an ultrasonic bath for 30 seconds. the dissolved material was then wet sieved using mesh sizes of 0.500 mm, 0.250 mm, 0.125 mm, and 0.063 mm. the specimens were hand­picked under a zeiss stemi 2000­c binocular magnifier with a magnification of × 50. approximately 100 adult ostracod valves were collected from each sample. picking was nonselective to preserve the original proportions of the species within the assemblage. this was done by collecting valves either until we reached 100 valves or until the sample was looked through fully. selected specimens were photographed on the jeol jsm 6490lv scanning electron microscope at the geological survey of slovenia. for determining the families of ostracods, the suprageneric classification scheme proposed by moore (1961) and horne et al. (2002) was used, as they are widely used classification schemes for ostracods. samples are stored at the geological survey of slovenia under field numbers geozs b­019 – b­057. the diversity was calculated using the shannon­wiener index (h) for each sample (shannon & weaver, 1949). 4. results the total stratigraphic thickness of the section is 43 m (fig. 7). a thin gravel layer at the base of the section is overlain by alternating sands and marls in 3 m thickness, with each sand and marl layer being approximately 20 to 30 cm thick (with a 1-meter-thick unlogged interval). the following 8-metre-thick sand has a sharp erosional base and clay intraclasts at the bottom part. the sand grades upward into marl, again overlain by a 10-metre-thick, dominantly sandy unit with an erosional base at 13 m. this unit contains thin clay and marl layers and even pebbly intervals at 17 m and between 20 and 21 m (fig. 7). the sand is overlain by a 7-metre-thick clay with sand intercalations. the top of the clay is eroded by a channel sandstone at 30 metres, with pebbles above the erosion surface. this sandstone is 7 metres thick and contains a few thin marl layers. marl predominates in the uppermost 6 m of the outcrop (fig. 7). a total of 30 ostracod species were determined (figs. 8­10 + supplement 1). in addition, 8 morphotypes were determined to the genus level. approximately 70 % of the collected valves were intact, and the rest were fragmented. only adult specimens were included in the palaeontological determination. diversity is strongly controlled by lithology: higher in marlstone, and lower in more sandy facies and claystone. the maximum value of diversity is 2.29 in sample b-024 at the 4 metre point of the section (taken from clay lithoclasts), but on averfigure 5. a simplified geological map by poljak et al. 2017, slightly modified. g eologia c roatica marinšek et al.: upper miocene ostracods from the krško basin, se slovenia 61 figure 6. a general stratigraphic column of the miocene deposits within the krško basin (modified after poljak et al., 2017). g eo lo gi a c ro at ic a geologia croatica 76/262 figure 7. sedimentary log and stratigraphic distribution of ostracod species in the section. the “diversity” column shows values of the shannon-wiener index as a measure of species richness and evenness. g eologia c roatica marinšek et al.: upper miocene ostracods from the krško basin, se slovenia 63 age the shannon­wiener diversity index values are between 1.0 and 1.5 (fig. 7). the most abundant specimens are from the genera cyprideis and hemicytheria. loxoconcha is present in most of the section but represents only a small percentage of the total assemblage. of the species observed here, the most important ones for determining the age were: amplocypris dorsobrevis sokač, caspiocypris alta (zalányi) and camptocypria aff. acronasuta (livental). 5. discussion 5.1. depositional environment the studied section begins with sandy facies which suggests a higher energy environment. indicators for this are mud chips and interbedded gravel. the environment changes at 22 metres from the beginning of the succession where we see a thick sequence of clay with thin layers of sand. at the 30 metre mark, the facies change again, with a rise in energy with an erosional channel in the clay, in which sand was deposited. the section ends with a lower energy environment indicated by marl deposition. these shifts in diversity and lithological changes correspond to rapidly changing conditions and lateral migration of the delta ( dalrymple et al., 1992). the ostracod genera cyprideis, hemicytheria, leptocythere and loxoconcha in the lowermost sand layer (0-2 m) indicate brackish conditions. ostracod diversity is low in this sandy part. moving upwards through the succession the ostracod diversity fluctuates significantly. diversity is highest in the marl­dominated part of the section, which can be explained by low-energy sedimentation and the reduced influence of fresh water. the diversity of the ostracod community reaches its highest value in sample b­024, which was taken from clay lithoclasts (fig. 6). the species cyprideis ex. gr. pannonica from that sample is considered by the authors to be reworked from older beds. further along the section, the diversity of the ostracod assemblage decreases drastically. the low values of diversity between samples b-035 and b-043 are due to the sudden intake of sand. the presence of cyprideis, hemicytheria, and loxoconcha indicates that beds from the upper part of the sequence were deposited under brackish conditions. previous research of the bizeljsko formation suggested deposition in a delta­front environment (poljak, 2017), and this interpretation is accepted here. it is to be noted that poljak (2017) does not describe any progradation and/or cyclic deposition, which would be typical for deltaic deposition as described and studied in sztanó et al. (2016), sebe et al. (2020) and špelić et al. (2023). this studied outcrop is too short to log any cyclic deposition apart from alternating marl and sand. according to hajek­tadesse (2007), the composition of the ostracod community of the bizeljsko profile, the preservation and abundance of ostracod shells depend on the change in the salinity of the lake water and the sedimentation. in general, the same author (hajek­tadesse, 2007) concluded that several changes in lake water salinity and ostracod fauna can be distinguished on the bizeljsko profile. at the beginning of the late pannonian, water salinity increases to mesohaline values, while in the uppermost samples of the late pannonian, the ostracod fauna of the bizeljsko profile takes on a more freshwater character and indicates deposition near fresh-water input and a near-shore environment as stated in poljak (2017). we agree with the paleoenvironmental interpretation of both hajek­tadesse (2007) and poljak (2017). 5.2. biostratigraphy there are quite a few ostracod biostratigraphic zonal schemes available for the pannonian stage (e.g., pokorný, 1944; brestenská, 1961; krstić, 1973, 1985; jiřiček, 1975, 1985; sokač 1972, 1989; jiřiček & riha 1991; and rundić, 1998, 2006). according to olteanu (2011), the ostracod assemblages are well­differentiated only between two units, the lower pannonian and the »portaferrian« (with congeria rhomboidea), and most of the known species cannot be considered reliable index fossils. the same author concludes that the biostratigraphy of the brackish-water facies, generally and especially of the pannonian basin, is also difficult to dtermine. a similar view was expressed by kovács et al. (2016). the same authors conclude that different ostracod biostratigraphic schemes have been erected in different parts of the pannonian basin system, but they usually reflect local characteristics and differ significantly from each other. the four most commonly used schemes for biozonation are presented in fig. 8. here, the biozonation by sokač (1989) was used. the great majority of the investigated section can be placed within the caspiocypris labiata subzone (fig. 8), which is the oldest subzone in the upper pannonian (previously known as upper pontian) bakunella dorsoarcuta zone (sokač, 1972; krstić 1973; sokač, 1989). the subzone is defined by caspiocypris labiata (zalányi), caspiocypris alta (zalányi) and c. caspiocypris pontica sokač. although the species caspiocypris labiata itself is absent, the defined subzone contains the typical caspiocypris form, such as caspiocypris alta. in addition, amplocypris aff. dorsobrevis sokač, camptocypria aff. acronasuta, typhlocypris cf. centropunctata, loxoconcha schweyeri are relatively abundant in this zone which is characteristic for this subzone. the camptocypria flectimarginata, which reaches its acme in the camptocypria flectimarginata subzone, rarely occurs in the studied section. however, the younger pontoniella truncata subzone is excluded due to the absence of the index species, as well as the lack of the usual accompanying species e.g., pontoniella paracuminata and hastacandona loczyi (jiřiček, 1983; sokač, 1989). the subzone was chosen out of all the others in the literature, due to the proximity of the localities where the subzone was defined, in agreement with the results of previous research undertaken around the studied area (sokač, 1981; hajek­tadesse, 2007). ostracods determined here only correspond to the described ostracod assemblages of the caspiocypris labiata subzone. the lowermost 3.5 m of the section does not contain species diagnostic of the caspiocypris labiata subzone, nor are there any species that would indicate the presence of the preceding, lower level of upper pannonian hemicytheria prisca sokač biozone. the latter ostracod zone was defined by krstić (1973) based on the nominate species, and the presence of the species pontoniella ilica krstić, zalanyiella longissima krstić, camptocypria acuta sokač, bakunella anae spadi (spadi et al., 2019), cyprideis salopeki sokač, and c. parallela krstić. in the investigated section, the species camptocypria acuta sokač and b. anae spadi occur in the lower part. the stratigraphic ranges of these species, however, extend to the upper pannonian. the lowermost 3.5 m of the section is therefore not defined in age. the species bakunella anae, characteristic of the upper pannonian (previously known as the lower and upper pontian) (sokač, 1972), was also observed in the sample b­024. the sample was collected from a marl lens within a sandstone bed, which is, as mentioned before, was interpreted as a clast eroded g eo lo gi a c ro at ic a geologia croatica 76/264 from the underlying beds. resedimentation of the fossils is also possible for samples b-035, b-037, and b-048 (see fig. 7). according to jiřiček & riha (1991), the equivalent ostracod zone for the caspiocypris labiata subzone is the lower pontian ostracod zone 20 “candona (c.) balcanicacandona (c.) lobata” in which there is the first occurrence of bakunella dorsoarcuata. however, in the biozonation set by jiřiček (1983), the species caspiocypris labiata is placed in the upper pannonian zone e 1-2. the correlation of biozones is further complicated by the different compositions of ostracod assemblages in various parts of the central paratethys (see pokorný, 1944; brestenská, 1961; krstić, 1973, 1985; jiřiček, 1975, 1985; rundić, 1998, 2006). also, there is much confusion related to the ostracod taxonomy, which needs a serious revision (see olteanu, 2011; spadi et al., 2019). 5.3. palaeosalinity levels the pannonian microfauna is dominated by brackish to freshwater ostracods which tolerate an increase in salinity (figs. 8 and 10). this suggests that the composition of the lake pannon ostracod assemblages is strongly facies dependent, as was previously demonstrated for the pannonian mollusc fauna (magyar et al., 1999). many of the detected ostracod species may tolerate a considerable range of salinity. the number of freshwater species diminishes when salinity surpasses 3‰, and the number of true brackish water species in the range from 3-10‰ is not numerous but the number of specimens is large (morkhoven, 1962). the important genera for determining palaeosalinity levels in the logged part of the bizeljsko formation are darwinula, candonopsis, pontoniella, lineocypris, camptocypria, caspiocypris, typhlocypris, bakunella, hemicytheria, leptocythere, amplocypris, and loxoconcha (tunoğlu, 2003). candonopsis and darwinula are specific to freshwater environments. according to meisch (2000), recent darwinula tolerates an increase in salinity up to a maximum of 15‰, and candonopsis from a maximum salt content of 5 ‰. considering the poor preservation of their valves in sample b-024 and their probable re-deposition they were excluded from the environmental interpretation. paleosalinity was determined to be in the range of brackish conditions. the interpretation is based on the presence of the genus hemicytheria, which was abundant in the section ( morkhoven,1962; meisch, 2000; frenzel & boomer, 2005). figure 8. four selected biozonation schemes proposed by different authors (krstić, 1973; sokač, 1989; jiřiček & riha, 1991; rundić, 2006) with the stratigraphic position of the study site. g eologia c roatica marinšek et al.: upper miocene ostracods from the krško basin, se slovenia 65 figure 9. sem pictures of pannonian ostracods from the bizeljsko section. 1. amplocypris subacuta zalányi (lv, external view, sample b-024, fragmented valve); 2. amplocypris cf. dorsobrevis sokač (lv, external view, sample b-051, fragmented valve); 3. herpetocyprella cf. pannonica zalanyi (lv, external view, sample b-048, fragmented valve); 4. bakunella anae (vekua) spadi (rv, external view, sample b-024), alternatively, possible juvenile of b. dorsoarcuata; 5a., 5b. bakunella dorsoarcuta zalányi (a. lv, external view, sample b-024; b. rv, internal view, sample b-024); 6. camptocypria acuta sokač (lv, internal view, sample b-027); 7. camptocypria cf. acronasuta livental (rv, internal view, sample b-027); 8. camptocypria flectimarginata sokač (lv, external view, sample b-031); 9. camptocypria? sp. (lv, external view, sample b-030); 10. candonopsis cf. arcana krstić (lv, external view, sample b-024); 11. caspiocypris alta zalányi (lv, internal view, sample b-031); 12. lineocypris reticulata (méhes) (lv, external view, sample b-057); 13. lineocypris hodonensis pokorný (rv, external view, sample b-027);14. lineocypris zagrabiensis sokač (rv, external view, sample b-041). g eo lo gi a c ro at ic a geologia croatica 76/266 5.4. comparison between the ostracod fauna from the pannonian deposits of the krško basin and other parts of the paratethys the ostracod fauna from the upper pannonian deposits of the krško basin, which includes taxa that were determined both here and in previously published papers (sokač, 1981; stevanović & škerlj, 1989; hajek­tadesse, 2007), was compared to the ostracod faunas of the same age reported from similar localities in the central paratethys. the results are presented in supplement 2. figure 10. sem pictures of pannonian ostracods from the bizeljsko section. 1. lineocypris cf. granulosa zalányi (lv, external view, sample b-024); 2. pontoniella sagittosa krstić (rv, external view, sample b-024); 3. pontoniella sp. 1 mandelstam (lv, external view, sample b-024); 4. pontoniella sp. 2 (lv, sample b-036); 5. typhlocypris cf. centropunctata suzin (lv, external view, sample b-038); 6. typhlocypris sp. (héjjas) (lv, external view, sample b-040); 7. cyprideis macrostigma kollmann (a. rv, external view, b. lv, internal view, sample b-036); 8. cyprideis macrostigma spinosa sokač (a. lv, external view, b. lv, internal view, sample b-032); 9. cyprideis ex gr. pannonica méhes (rv, external view, sample b-024); 10. cyprideis ex gr. pannonica méhes (rv, external view, sample b-027); 11. cyprideis ex gr. pannonica méhes (rv, external view, sample b-020); 12. cyprideis sp. 1 (rv, external view, sample b-023); 13. cyprideis sp. 2 (lv, external view, sample b-023). g eologia c roatica marinšek et al.: upper miocene ostracods from the krško basin, se slovenia 67 in the comparison, from the literature, we only included upper pannonian ostracod species. the ostracod assemblage from the krško basin is most similar to that from mt. medvednica as the locality is very close by. out of 73 species found in the krško basin, in total, croatia has 43 of the same species from similar deposits. the resemblance with croatia was expected as it belongs to the same system of supposed basins and the location of the outcrop and samples are only a few kilometres away from the comparison locations studied on mt. medvednica and reported in the literature. ostracod assemblages from romania and serbia have, respectively, 29 and 33 species in common with krško basin. the vienna basin only has 13 species similar to those recorded at bizeljsko. regarding serbia and romania, the number of similar species indicates a good connection with the central paratethys. papers involving the older pannonian ostracods (e.g., vrsaljko, 1999; kovács et al., 2016; csoma et al., 2021), as well as pannonian ostracods from austria /vienna basin (gross, 2004; gross et al., 2008; starek et al., 2010) are not included in supplement 2. apart from these localities, some ostracods are the same species as the ones that migrated from paratethys to the palaeo-mediterranean. these are caspiocypris alta and euxinocythere (m.) cf. praebaquana (gliozzi et al., 2012). figure 11. sem pictures of pannonian ostracods from the bizeljsko section. 1. cyprideis sp. 3 (lv, external view, sample b-023); 2. hemicytheria croatica sokač (lv, external view, sample b-024); 3. hemicytheria cf. marginata sokač (lv, external view, sample b-024); 4. hemicytheria cf. prisca sokač (rv, external view, sample b-030); 5. hemicytheria dubokensis krstić (lv, juvenile, external view, sample b-026); 6. amnicythere naca (méhes) (lv, external view, sample b-052); 7. amnicythere sp. (lv, external view, sample b-020); 8. leptocythere? sp. (lv, external view, sample b-051); 9. euxinocythere (maeotocythere) cf. praebaquana (livental) (rv, external view, sample b-033); 10. darwinula cf. stevensoni brady & robertson (lv, external view, sample b-024) fragmented due to handling of the specimen; 11. loxoconcha schweyeri suzin (lv, external view, sample b-024); 12. loxoconcha cf. spinosa sokač (lv, external view, sample b-024). g eo lo gi a c ro at ic a geologia croatica 76/268 6. conclusions the pannonian ostracods studied from the 43 m thick lithological succession (bizeljsko fm., krško basin) are relatively well preserved and diverse. the determined species delineate the late pannonian caspiocypris labiata subzone. palaeosalinity levels, as indicated by the ostracods, show brackish water conditions. comparison with the ostracod assemblages from the region shows the highest similarity in species composition to the fauna from croatia, less so with faunas from serbia and romania. within the bizeljsko ostracod assemblage, two species are recognised that migrated from paratethys to the palaeo-mediterranean during the lago­mare event of the messinian salinity crisis. acknowledgment this work is part of the ongoing phd research financially supported by the slovenian research agency (arrs), within the program group regional geology (p1­0011). we thank marija petrović for the preparation of the samples. references aničić, b. & juriša, m. (1985a): osnovna geološka karta sfrj, 1:100.000, list rogatec [basic geological map of the sfry, 1:100000, sheet rogatec – in slovenian].– zvezni geološki zavod, beograd. aničić, b. & juriša, m. (1985b): osnovna geološka karta sfrj 1:100.000 – tolmač za list rogatec [basic geological map of sfry 1:100000 – explanatory book for the rogatec sheet – in slovenian].– zvezni geološki zavod, beograd, 76 p. arsovski, m., stojković, m., mihailov, v. & petrovski, d. (1975): summary of the geological and seismological investigation of the nuclear power plant „krško“ location.– institute of earthqake engineering and engineering seismology, university kiril and metod, skopje, 33 p. avanić, r., pavelić, d., miknić, m., bakrač, k., kovačić, m., vrsaljko, d., pikija, m., brkić, m., basch, o. & sarkotić šlat, m. (2022b): formacija medvedski breg (meb) [medvedski breg formation (meb) – in croatian].– in: halamić, j. & belak, m. (eds.): tumač za požešku goru. [explanatory book for požeška gora – in croatian]. hrvatski geološki institut, zagreb, 122–123. bartol, m. (2009): middle miocene calcareous nannoplankton of ne slovenia (western central paratethys).– paleontološki inštitut ivana rakovca zrc sazu, ljubljana, 142 p. doi: 10.3986/9789612545598 basch, o., brkić, m., grizelj, a., kovačić, m., miknić, m., sarkotić šlat, m. (2022): formacija nova gradiška (ngr) [nova gradiška formation (ngr) – in croatian].– in: halamić, j. & belak, m. (eds.): tumač za požešku goru [explanatory book for požeška gora – in croatian]. hrvatski geološki institut, zagreb, 124–127. bartha, i.r., botka, d., csoma, v., katona, l.t., tóth, e., magyar, i., silye, l. & sztanó, o. (2021): from marginal outcrops to basin interior: a new perspective on the sedimentary evolution of the eastern pannonian basin.– int. j. earth sci. (geol rundsch), 111, 335–357. doi: 10.1007/s00531­021­02117­6 brestenská, e. (1961): present knowledge and problems of the pliocene of the west carpathians.– geol. bratislava, prace, zošit, 60, 149–157. cigit, k. (1958): o geoloških razmerah filovske naftne strukture [the geological settings of the filovci oil structure – in slovenian].– geologija, 4, 171–187. csoma, v., magyar, i., szuromi­korecz, a., sebe, k., sztanó, o., buczkó, k. & tóth, e. (2021): pannonian (late miocene) ostracod fauna from pécs­ danitzpuszta in southern hungary.– foldtani kozlony, 151/3, 305–326. doi: 10.23928/foldt.kozl.2021.151.3.305 cziczer, i., magyar, i., pipík, r. böhme, m., ćorić, s., bakrač, k., sütő­ szentai, m., lantos, m., babinszki, e. & müller, p. (2008): life in the sublittoral zone of long­lived lake pannon: paleontological analysis of the upper miocene szák formation, hungary.– int. j. earth sci. (geol rundsch), 98, 1741–1766. doi: 10.1007/s00531­008­0322­3 dalrymple, r.w., zaitlin, b.a. & boyd, r. (1992): estuarine facies models: conceptual basis and stratigraphic implications.– j. sediment. petrol., 62/6, 1130–1146. doi: 10.1306/d4267a69­2b26­11d7­8648000102c1865d djurasek, s. (1995): interpretacija refleksijskih seizmičnih profila na krškom polju (kp­ 83­59, kp­84­59, kp­85­59, kp­86­59) [interpretation of reflection seismic profiles in krško polje (kp-83-59, kp-84-59, kp-85-59, kp-86-59 – in slovenian].– uprava rs za jedrsko varnost, geološki zavod slovenije, ljubljana. frenzel, p. & boomer, i. (2005): the use of ostracods from marginal marine, brackish waters as bioindicators of modern and quaternary environmental change.– palaeogeogr. palaeocl., 225, 68–92. doi: 10.1016/j.palaeo.2004.02.051 floroiu, a., stoica, m., vasiliev, i. & krijgsman, w. (2011): maeotian/pontian ostracods in the badislava –topolog area (south carpathian foredeep­romania).– geo-eco-marina, 17, 237–244. gliozzi, e., grossi, f., cosentino, d. & iadanza, a. (2012): the late messinian lago-mare biofacies in central apennines: the ostracod prespective.– rend. online soc. geol. it., 23, 63–65. gross, m. (2004): zur ostracodenfauna (crustacea), paläoökologie und stratigrafie der tongrube mataschen (unter­pannonium, steirisches becken, österreich).– joannea geol. paläontol., 5, 49–130. gross, m., minati, k., danielopol, d. & piller, w. (2008): environmental changes and diversification of cyprideis in the late miocene of the styrian basin (lake pannon, austria).– palaeobio. palaeoenv., 88, 161–181. doi: 10.1007/ bf03043987 hajek­tadesse, v. (2007): mikropaleontološke analize uzoraka profila bizeljsko [micropaleontological analyzes of bizeljsko profile samples – in croatian].– unpubl. report, hrvatski geološki institut, 15 p. horne, d., cohen, a. & martens, k. (2002): taxonomy, morphology and biology of quaternary and living ostracoda.– in: holmes, j.a. & chivas, a.r. (eds.): the ostracoda: applications in quaternary research. geophysical monograph series. 131 p. doi: 10.1029/131gm02 ivančič, k. (2021): pregled sedimentacijskega razvoja in formacij na območju slovenije v miocenu [overview of sedimentary development and formations in the area of slovenia in the miocene – in slovenian].– in: rožič, b. (ed.): treatises, reports = 25th meeting of slovenian geologists. univerza v ljubljani, naravoslovnotehniška fakulteta, oddelek za geologijo, 31–35. jelen, b., aničić, b., brezigar, a., buser, s., cimerman, f., drobne, k., monostori, m., kedves, m., pavšič, j. & skaberne, d. (1992): model of positional relationships for upper paleogene and miocene strata in siovenia.– in: montanari, a., coccioni, r. & odln, g.s. (eds.): interdisciplinary geological conference on the miocene epoch with emphases on the umbria­marche­ sequence. international union of geological sciences, subcommission on geochronology, ancona, 71–72. jelen, b. & rifelj, h. (2002): stratigrafska zgradba terciarne tektonostratigrafske enote b1 v vzhodni sloveniji. stratigraphic structure of tertiary tectonic stratigraphic unit b1 in eastern slovenia.– geologija, 45/1, 115–138. jiřiček, r. (1975): biozonal division of the upper tertiary basins of the eastern alps and west carpathians rcmnsvi congress, iugs comm.– stratigr., 11–147. jiřiček, r. (1983): redefinition of the oligocene and neogene ostracod zonation of the paratethys.– knihovnička zemního plynu a nafty, 4, 195–236. jiřiček, r. (1985): die ostracoden des pannonien.– chronostratigraphie und neostratotypen. miozän der zentralen paratethys, 7, 378–425. jiřiček, r, & riha, j. (1991): correlation of ostracod zones in the paratethys and tethys. – saito ho–on kai special publications (proceedings of shallow tethys), 3, 435–457. kaloper, d. (1984): krško polje­brežice, analogna obrada profila kp­83­59, kp­84­ 59, kp­85­59, kp­86­59 [krško field brežice, analog processing of profile kp83-59, kp-84-59, kp-85-59, kp-86-59 – in slovenian] – geofizika, 3 p., zagreb. krstić, n. (1972): rod candona (ostracoda) iz kongerijskih slojeva južnog dela panonskog basena) [genus candona (ostracoda) from congeria beds of southern pannonian basin – in serbian, with an english summary].– serbian academy of science and arts, vol. cdl, sec. nat. math. sci., 39, 145 p., xxx plates, belgrade. krstić, n. (1973): biostratigrafija kongerijskih slojeva okoline beograda na osnovu ostrakoda. biostratigraphy of congerian layers around belgrade based on ostracods.– posebno izd. inst. geol. geof. istr. ispitivanja nuklearnih i drugih mineralnih surovina, 4, 5–158. krstić, n. (1985): ostracoden im pannonien der umgebung von belgrad.– in: papp, a., jámbor, á. & steining er, f.f. (eds.): chronostratigraphie und neostratotypen, miozän der zentralen paratethys 7, pannonien. akadémiai kiadó, budapest, 103–144. kovács, e., magyar, i., sztanó, o. & pipík, r. (2016): pannonian ostracods from the southwestern transylvanian basin.– geol. croat., 69/2, 213–229. doi: 10.4154/gc.2016.16 kovac, m., hudáčková, n., halásová, e., kováčová, m., holcová, k., oszczypko­clowes, m., báldi, k., less, g., nagymarosy, a., ruman, a., klučiar, t. & jamrich, m. (2017): the central paratethys palaeoceanography: a water circulation model based on microfossil proxies, climate, and changes of depositional environment.– acta geol. slovaca, 9/2, 75–114. kuščer, d. (1973): summary of reports on preliminary geologic site investigations for the krško nuclear power plant.– geološki zavod ljubljana. lapajne, v. (1976): kremenov pesek bizeljsko [flint sand bizeljsko – in slovenian].– unpubl. report, ljubljana, geološki zavod, 40 p. lazarev, s., de leeuw, a., stoica, m., mandić, o., van baak, c.g.c., vasiliev, i. & krijgsman, w. (2020): from khersonian drying to pontian “flooding”: late miocene stratigraphy and palaeoenvironmental evolution of the dacian basin (eastern paratethys).– glob. planet. change, 192, 03224. doi: 10.1016/j.gloplacha.2020.103224 g eologia c roatica marinšek et al.: upper miocene ostracods from the krško basin, se slovenia 69 magyar, i., geary, d.h. & müller, p. (1999): palaeogeographic evolution of the late miocene lake pannon in central europe.– palaeogeogr. palaeocl., palaeoecol. 147, 151–167. doi: 10.1016/s0031­0182(98)00155­2 magyar, i., sztanó, o., sebe, k., katona, l., csoma, v., görög, á., tóth, e., korecz, a., šujan, m., braucher, r., ruszkiczay­rüdiger, z., koroknai, b., wórum, g., sant, k., kelder, n. & krijgsman, w. (2019): towards a high-resolution chronostratigraphy and geochronology for the pannonian stage: significance of the paks cores (central pannonian basin).– föld­ tani közlöny, 149, 351. doi: 10.23928/foldt.kozl.2019.149.4.351 marković, s. & mioč, p. (1988): osnovna geološka karta sfrj 1:100.000 (list nađkaniža) [basic geological map of sfrj 1:100000 l 33-58 (sheet nađkaniža) – in slovenian]. – zvezni geološki zavod beograd. marinšek, m. (2020): ostrakodna združba zgornjemiocenskih plasti na bizeljskem [ostracod fauna from upper miocene beds from bizeljsko – in slovenian, abstract in english]. – master‘s thesis. univerza v ljubljani. 108 p. meisch, c. (2000): freshwater ostracoda of western and central europe.– spektrum, akademischer verlag (gustav fischer), heidelberg, 1st edition, 522 p. mikuž, v. (2005): pannonian molluscs from surroundings of čanje near sevnica, slovenia.– geologija, 48/2, 225–243. doi: 10.5474/geologija.2005.019 mikuž, v. (2014): some rare fossils from slovenske gorice, slovenia.– geologija, 57/2, 155–166. doi: 10.5474/geologija.2014.013 mikuž, v., križnar, m. & caf, n. (2015): pannonian moluscs from site osek­2 in slovenske gorice, slovenia.– geologija, 58/1, 71–80. doi: 10.5474/geologija.2015.006 mioč, p. & žnidarčič, m. (1978): osnovna geološka karta sfrj 1:100.000 l 33­55 (list slovenj gradec) [basic geological map of sfrj 1:100,000 l 33-55 (list = sheet slovenj gradec) – in slovenian].– zvezni geološki zavod, beograd, 74 p. mioč, p. & žnidarčič, m. (1989): osnovna geološka karta sfrj 1:100.000 (tolmač maribor in leibnitz) [basic geological map of sfrj 1:100,000 (explanatory book maribor and leibnitz) – in slovenian].– zvezni geološki zavod, beograd, 60 p. moore, r.c. ed. (1961): treatise on invertebrate paleontology. part q, arthropoda. 3, crustacea, ostracoda.– boulder; lawrence: geological society of america; university of kansas. morkhoven, van f.p.c.m. (1962): post­paleozoic ostracoda, their morphology, taxonomy and economic use, part 2.– elsevier, new york, 478 p. olteanu, r. (2011): atlas of the pannonian and pontian ostracods from the eastern area of the pannonian basin.– geo-eco-marina, 17, 135–177. doi: 10.5281/zenodo.45062 pavelić, d. (2005): cyclicity in the evolution of the neogene north croatian basin (pannonian basin system).– in: mabesoone, j.m. & neumann, v.h. (eds.): cyclic development of sedimentary basins. developments in sedimentology, vol. 57. elsevier, amsterdam, 273–284. doi: 10.1016/s0070­4571(05)80011­1 pavšič, j. & horvat, a. (2009): eocen, oligocen in miocen v osrednji in vzhodni sloveniji, eocen in oligocen [the eocene, oligocene and miocene in central and eastern slovenia, eocene and oligocene – in slovenian and english].– in: pleničar, m., ogorelec, b. & novak, m. (eds.): geologija slovenije [the geology of slovenia – in slovenian and english], geološki zavod slovenije, 373–390. pierau, h. (1958): zur stratigraphie und tektonik jungtertiärer ablagerungen im nordwestlischen krško polje in slowenien [on the stratigraphy and tectonics of late tertiary deposits in the northwestern krško polje in slovenia – in german].– geologija, 4, 111–148. piller, w.e., harzhauser, m. & mandic, o. (2007): miocene central paratethys stratigraphy – current status and future directions.– stratigraphy, 4, 2/3, 151–168. pleničar, m. (1954): obmurska naftna nahajališča [oil fields of the mura river area – in slovenian].– geologija, 2, 36–93. pleničar, m. (1968): osnovna geološka karta sfrj (list goričko) [basic geological map of sfrj 1:100.000 l 33-45 (sheet goričko) – in slovenian].– zvezni geološki zavod, beograd. placer, l. (1999a): prispevek k makrotektonski rajonizaciji mejnega ozemlja med južnimi alpami in zunanjimi dinaridi [contribution to the macrotectonic regionalization of the borderland between the southern alps and the outer dinarides – in slovenian].– geologija, 41/1, 223–243. placer, l. (1999b): strukturni pomen posavskih gub [structural significance of the posavina folds – in slovenian, with an english abstract].– geologija, 41/1, 191–221. pokorný, v. (1944): la microstratigraphie du pannonien entre hodonin et mikulcice (moravie meridionale, tchecoslovaquie) [the pannonian microstratigraphy between hodonin and mikulcice (south moravia, czechoslovakia) – in french].– bull. inter. acad. tcheque. sci., 23, 1–25. poljak, m. (2017): geološka karta vzhodnega dela krške kotline 1:25.000, tolmač [geological map of the eastern part of the krško basin 1:25.000: explanatory booklet – in slovenian].– geološki zavod slovenije, ljubljana, 109 p. poljak, m., rižnar, i., demšar, m., novak, m. & toman, m. (2017): geološka karta vzhodnega dela krške kotline 1: 25.000 [geological map of the eastern part of the krško basin 1:25.000].– geološki zavod slovenije, ljubljana. premru, u. & marinčić, s. (1971): tektonska zgradba jugovzhodne slovenije in severozahodne hrvatske, študija za projekt nuklearne elektrarne v krškem [tectonic structure of southeastern slovenia and northwestern croatia, study for the nuclear power plant project in krško – in slovenien].– geološki zavod ljubljana, 24 p. rundić, l. (1997): biostratigrafija kaspibrakičnog neogena kolubarskog basena [biostratigraphy of the caspibrackish neogene of the kolubara basin – in serbian, with an english abstract].– unpubl. phd thesis, faculty of mining and geology, university of belgrade, 128 p. rundić, l. (1998): the carapace of fossil ostracodes: paleoenvironmental indicators.– ann. géol. pénins. balk., 62, 165–177. rundić, l. (2006): late miocene ostracodes of serbia: morphologic and paleoenvironmental considerations.– ann. géol. pénins. balk., 67, 89–100. doi: 10.2298/gabp0667089r rundić, l., ganić, m., knežević, s. & soliman, a. (2011): upper miocene pannonian sediments from belgrade (serbia): new evidence and paleoenvironmental considerations.– geol. carpath., 62/3, 267–278. doi: 10.2478/v10096­011­ 0021-z rundić, l., ganić, m., knežević, s., radivojević, d. & radonjić, m. (2019): stratigraphic implications of the mio­pliocene geodynamics in the area of mt. avala: new evidence from torlak hill and beli potok (belgrade, serbia).– geol. croat., 72/ 2, 109–128. doi: 10.4154/gc.2019.11 sebe, k., kovačić, m., magyar, i., krizmanić, k., špelić, m., bigunac, d., sütő­szentai, m., kovács, a., szuromi­korecz, a., bakrač, k., hajek­tadesse, v., troskot­čorbić, t. & sztanó, o. (2020): correlation of upper miocene-pliocene lake pannon deposits across the drava basin, croatia and hungary.– geol. croat., 73/3, 177–195. doi: 10.4154/gc.2020.12 shannon, c.e. & weaver, w. (1949): the mathematical theory of communication.– the university of illinois press, urbana, 117 p. skaberne, d. (1990): makroskopski opis jedrovanih odsekov vrtine drn­1 (drnovo na krškem polju) [macroscopic description of cored sections of well drn-1 (drnovo na krško polje) – in slovenian].– in: kranjc et al. (eds.): končno poročilo o geoloških raziskavah na krškem polju za potrebe podzemnega skladiščenja plina –vrtina drn­1/89 [final report on geological research in the krško polje for the needs of underground gas storage – well drn-1/89 – in slovenian]. ljubljana, geoološki zavod slovenije, 19 p. sokač, a. (1972): pannonian and pontian ostracode fauna of medvednica.– pal. jugoslav., 11, 1–140. sokač, a. (1981): pannonian and pontian ostracode fauna of the south­eastern slopes of orlica and krško polje.– geol. vjesnik, 33, 95–99. sokač, a. (1989): pontian ostracod fauna in the pannonian basin.– in: malez, m. & stevanovič, p. (eds.): chronostratigraphie und neostratotypen, pliozan, pontien, bd. viii. jugosl. akad. d. wissen. und kunste, 672–700. spadi, m., gliozzi, e., boomer, i., stoica, m. & athersuch j. (2019): taxonomic harmonization of neogene and quaternary candonid genera (crustacea, ostracoda) of the paratethys.– j. syst. palaeontol., 17/19, 1665–1698. doi: 10.1080/14772019.2018.1545708 starek, d., pipík, r. & hagarová, i. (2010): meiofauna, trace metals, toc, sedi­ mentology, and oxygen availability in the late miocene sublittoral deposits of lake pannon.– facies, 56, 369–384. doi: 10.1007/s10347­009­0208­2 stevanović, p. & škerlj, ž. (1985): prilog biostratigrafiji panonsko­pontskih sedi­ menata u okolini videm­krškog [annex to the biostratigraphy of the pannonianpontic sediments in the vicinity of videm-krško – in croatian].– razprave iv, 281–304. stevanović p. & škerlj, ž. (1989): the pontian sediments of slovenia.– in: malez, m. & stevanovič, p. (eds.): chronostratigraphie und neostratotypen, pliozan, pontien, bd. viii. jugosl. akad. d. wissen. und kunste, 153–179. sztanó, o., kováč, m., magyar, i., šujan, m., fodor, l., uhrin, a., rybár, s., csillag, g. & tőkés, l. (2016): late miocene sedimentary record of the danube/kisalföld basin: interregional correlation of depositional systems, stratigraphy and structural evolution.– geol. carpath., 67/6, 525–542. doi: 10.1515/ geoca­2016­0033 szuromi­korecz, a., suto­szentai, m. & magyar, i. (2004): biostratigraphic revision of the hód­i well: hungary’s deepest borehole failed to reach the base of the upper miocene pannonian stage.– geol. carpath., 55/6, 475–485. šikić, k., basch, o. & šimunič, a. (1979): osnovna geološka karta sfrj 1:100000, tumač za list zagreb [basic geological map of the sfry 1:100000, explanation book for the zagreb sheet – in croatian].– geol. zavod zagreb, savezni geol. zavod, beograd, 81. škerlj, ž. (1990): mikropaleontološke analize in biostratigrafska interpretacija, vrtina dnr­1, (interval 194­50m) [micropaleontological analyzes and biostratigraphic interpretation, well dnr-1, (interval 194-50m) – in slovenian].– in: kranjc et al. (eds.): končno poročilo o geoloških raziskavah na krškem poljuza potrebe podzemnega skladiščenja plina –vrtina drn­1/89 [final report on the geological research in the krško basin of the need for underground gas storage – well drn-1/89 – in slovenian]. unpubl. report, ljubljana, geozs, 19 p. g eo lo gi a c ro at ic a geologia croatica 76/270 špelić, m., kovács, á., saftić, b. & sztanó, o. (2023): competition of deltaic feeder systems reflected by slope progradation: a high­resolution example from the late miocene­pliocene, drava basin, croatia.– int. j. earth sci. (geol rundsch), 112, 1023–1041. doi: 10.1007/s00531-023-02290-w šram, d., rman, n., rižnar, i. & lapanje, a. (2015): the three­dimensional regional geological model of the mura­zala basin, northeastern slovenia.– geologija, 58/2, 139–154. doi: 10.5474/geologija.2015.011 ter borgh, m., vasiliev, i., stoica, m., knežević, s., matenco, l., krijgsman, w., rundić, l. & cloetingh, s. (2013): the isolation of the pannonian basin (central paratethys): new constraints from magnetostratigraphy and biostratigraphy.– global. planet. change., 103, 99–118. doi: 10.1016/j.gloplacha.2012.10.001 trajanova, m. (2006): granulometrijska in litološka sestava vzorcev proda iz lokacije vrbina (sv. urh in libna) [granulometric and lithological composition of gravel samples from the vrbina location (sv. urh and libna) – in slovenian].– unpubl. report, geološki zavod slovenije, ljubljana, 9 p. tunoğlu, c. (2003): systematics and biostratigraphy of the pontian candonidae (ostracoda) from the eastern black sea region (northern turkey).– geol. carpath., 54/1, 21–40. vesel­lukić, m. (2012): panonijska in pontijska ostrakodna favna krške kotline (vzhodna slovenija, centralna paratetida) [pannonian and pontic ostracod fauna of the krška basin (eastern slovenia, central paratetida) – in slovenian].– in: atanackov, j., jamšek rupnik, p. & markič, m. (eds.): abstract book. geološki zavod slovenije, ljubljana, p. 21. vesel­lukić, m., hajek­tadesse, v. & poljak, m. (2013). late miocene ostracoda from bizeljsko section (eastern slovenia).– in: il naturalista siciliano palermo: tipolitografia luxograph s.r.i, 413–414. vesel­lukić, m., hajek­tadesse, v. & poljak, m. (2014). paleoekologija zgornjemiocenskih ostrakodov profila bizeljsko [palaeoecology of upper miocene ostracods from bizeljsko section – in slovenian].– in: rožič, b., verbovšek, t. & vrabec, m. (eds.) (2014): povzetki in ekskurzije [abstracts and field trips – in slovenian]. univerza v ljubljani, naravoslovnotehniška fakulteta, ljubljana, 73–74. vončina, z. (1966): strukturni i litofacijelni odnos lendavske formacije u mursko sobotskoj zoni [structural and lithophacial relations of lendava formation in the murska sobota zone – in serbo­croatian].– ina naftaplin zagreb, archive geozs, 37 p. vrsaljko, d. (1999): the pannonian palaeoecology and biostratigraphy of molluscs from kostanjek – medvednica mt., croatia.– geol. croat., 52/1, 9–27. žnidarčič, m. & mioč, p. (1987): osnovna geološka karta sfrj 1:100.000 l 33­56 in l 33-44, list maribor in leibnitz [basic geological map of sfrj 1:100000 l 33-56 and l 33-44, sheets maribor and leibnitz – in slovenian].– zvezni geološki zavod, beograd. g eologia c roatica marinšek et al.: upper miocene ostracods from the krško basin, se slovenia 71 appendix: supplement 1. systematic list of determined ostracod species in this study. class ostracoda latreille, 1802 subclass podocopa sars, 1866 order podocopida sars, 1866 suborder cypridocopina baird, 1845 superfamily cypridoidea baird, 1845 family cyprididae baird, 1845 amplocypris zalányi, 1944 amplocypris subacuta zalányi, 1944 amplocypris cf. dorsobrevis sokač, 1972 subfamily herpetocyprellinae bronstein, 1947 herpetocyprella daday, 1909 herpetocyprella cf. pannonica zalányi, 1959 family candonidae kaufmann, 1900 subfamily candoninae kaufmann, 1900 bakunella schneider, 1958 bakunella anae (vekua) spadi, 2019 bakunella dorsoarcuta zalányi, 1929 camptocypria zalányi, 1959 camptocypria acuta sokač, 1972 camptocypria cf. acronasuta (livental, 1929) camptocypria flectimarginata sokač, 1967 camptocypria? sp. candonopsis vavra, 1891 candonopsis cf. arcana krstić, 1968 caspiocypris mandelstam in schneider et al., 1956 caspiocypris alta (zalányi, 1929) lineocypris zalányi, 1929 lineocypris reticulata (méhes, 1907) lineocypris hodonensis pokorný, 1952 lineocypris zagrabiensis sokač, 1972 lineocypris cf. granulosa zalányi, 1959 pontoniella mandelstam in luebimova et al., 1960 pontoniella sagittosa krstić, 1968 pontoniella spp. typhlocypris vejdovský, 1882 (sensu namiotko et al. 2014) typhlocypris cf. centropunctata (suzin, 1956) typhlocypris sp. superfamily cytheroidea baird, 1850 family cytherideidae sars, 1925 subfamily cytherideinae sars, 1925 cyprideis jones, 1857 cyprideis macrostigma kollmann, 1958 cyprideis macrostigma spinosa sokač, 1972 cyprideis ex. gr. pannonica (méhes, 1908) cyprideis spp. family hemicytheridae puri, 1953 subfamily hemicytherinae puri, 1953 hemicytheria pokorný, 1955 hemicytheria croatica sokač, 1963 hemicytheria cf. marginata sokač, 1972 hemicytheria cf. prisca sokač, 1972 hemicytheria dubokensis krstić, 1963 family leptocytheridae sars, 1925 amnicythere devoto, 1965 amnicythere naca (méhes, 1909) amnicythere sp. leptocythere sars, 1925 leptocythere sp. euxinocythere (maeotocythere) stancheva, 1968 euxinocythere (m.) cf. praebaquana (livental, 1956) family loxoconchidae sars, 1925 loxoconcha sars, 1866 loxoconcha schweyeri suzin, 1956 loxoconcha cf. spinosa sokač, 1972 superfamily darwinuloidea brady & robertson, 1885 family darwinulidae brady & robertson, 1885 darwinula brady & robertson, 1885 darwinula cf. stevensoni brady & robertson, 1870 g eo lo gi a c ro at ic a geologia croatica 76/272 su pp le m en t 2 . t ab le s ho w in g th e re gi on al d is tr ib ut io n of u pp er p an no ni an o st ra co d sp ec ie s fo un d in th e kr šk o ba si n (s o ka č, 1 97 2; k rs ti ć, 1 97 3; s o ka č, 1 98 1, 1 98 9; s te va n o vi ć & š ke rl j, 19 89 ; s zu ro m i-k o re cz e t a l., 2 00 4; h a je kta d es se , 2 00 7; c zi cz er e t a l., 2 00 9; f lo ro iu e t a l., 2 01 1; o lt ea n u , 2 01 1; r u n d ić e t a l., 2 01 1; t er b o rg h e t a l., 2 01 3; m ag ya r et a l., 2 01 9; r u n d ić e t a l., 2 01 9; l a za re v et a l., 2 02 0; b a rt h a e t a l., 2 02 1; a va n ić e t a l., 2 02 2b ; ba sc h e t a l., 2 02 2) . 2019 | 72/3 | 163–172 | 2 figs. | 3 pls. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction cordaitalean remains from the bohemian part of the intrasudetic basin have been known to palaeobotanists since the 19th century [e.g. cordaites platynervis (göppert, 1864) grand’eury, 1877]. since then, tens of cordaites species have been described based on leaf morphology and venation. however, it has been shown that venation can be strongly influenced by both tapho­ nomic and preservation conditions (crookall, 1970). more­ over, many species have been described based on incomplete spec­ imens, without their base, or apex, and such specimens are difficult to compare with other specimens only by the means of venation. in reality, the situation is more complicated, because both leaf morphology and venation have some natural variability caused by the edaphic and climatic conditions in which the plant grew. the most stable feature seems to be the cuticle. cordaitalean cuticles have been studied by florin (1931), and more systematically by barthel (1962, 1964, 1976), ledran (1960, 1966), and rabitz (1966). barthel (1962, 1964, 1976) found that one species [e.g. cordaites principalis (germar) geinitz] can have different cuticles, that he named type 1 to type 8. bar­ thel (1976) was aware of the problem of the correct determina­ tion of cordaites species and came to the conclusion that it is not possible to distinguish three long­leaved cordaites species – c. borassifolius (sternberg) unger, c. palmaeformis (göp­ pert) weiss and c. principalis (germar) geinitz, and he suggested calling them “cordaites sp.” this interpretation helps to avoid problems in the determination of cordaites species, but it does not enable recognition of the diversity of this group and/or the specification of the number of cordaites species per locality. barthel (2009, 2016) did not change his mind and classified all samples as cordaites sp. from the quantity of cordaites names, only cordaites borassifolius, c. palmaeformis and c. principalis dominate in the revision of the genus cordaites unger from the permian of the intrasudetic basin (broumov formation, olivětín member, czech republic) zbyněk šimůnek czech geological survey, klárov 3/131, 118 21 praha 1, czech republic; (zbynek.simunek@geology.cz) doi: 10.4154/gc.2019.16 abstract cordaitalean remains are not very common in the permian of the intrasudetic basin (czech republic and poland) and have usually been classified simply as cordaites sp. based on leaf morphology, venation and cuticles (where possible), five cordaitalean species are recognised: cordaites cf. beinertianus, c. cf. affinis, c. cf. roesslerianus, c. cf. foliolatus and cordaites sp. a. the determination of cordaites leaves is difficult because of the variability and similarities between several species. the biggest leaf was determined as cordaites cf. beinertianus. the cuticles of cordaites cf. affinis resemble the cuticles of c. palmaeformis and c. radvanicensis, however, the latter is known only in a fragmentary state. cordaites beinertianus and c. palmaeformis are very similar and are considered as conspecific by some authors. cordaites affinis has generally smaller leaves. cordaites cf. roesslerianus is comparable with c. principalis with which it is sometimes synonymised. c. cf. foliolatus is represented by a much narrower leaf than is typical for cordaitalean leaves from france. cordaites sp. a is a relatively small leaf-form and differs from all other forms previously described. pa laeobotanical literature. as shown above, these species are under­ stood by different authors in different ways, and only cuticles from the type material will help to solve the problem of the accurate determination of these species. cuticles of cordaites borassifolius were described as amphistomatic with dispersed stomata on the adaxial cuticle, and stomatiferous and non­stomatiferous bands on the abaxial cuticle (šimůnek et al., 2009). studying cuticles of cordaites palmaeformis was difficult due to poor preservation, but eventually the stomata were shown to be arranged in stomatal rows on both cuticles (šimůnek, 2015). a problem remains with cordaites principalis, because its holotype is preserved as an impression in fine-grained sandstone that does not allow cu­ ticular study (šimůnek, 2015). some cordaitalean remains were discovered during the study of flora from the olivětín member in the intrasudetic basin. be­ cause some of these remains were large and some contain coal matter suitable for cuticular study, description of these specimens by the author was possible. 2. material and methods the specimens are stored in the collections of the national mu­ seum in prague and the museum of eastern bohemia in hradec králové (no. 74574 and 74575). all specimens came from the otovice locality (national museum), and otovice, černý potok (black creek) limestone (museum of eastern bohemia). all were from the permian (latest asselian) broumov formation, olivětín member (opluštil et al. 2016, table 1). three cordaites speci­ mens were macerated and slides no. 698/1­16, 699/1 and 700/1­4 prepared. the method used involved maceration in schulze’s reagent, as described previously by kerp (1990), krings & kerp (1997) and kerp & krings (1999). coalified fragments of article history: manuscript received june 06, 2019 revised manuscript accepted september 10, 2019 available online october 31, 2019 keywords: cordaites, permian flora, intrasudetic basin g eo lo gi a c ro at ic a geologia croatica 72/3164 leaves were separated from the rock by needle or by hydrofluoric acid (hf) digestion. these fragments were bleached in schulze’s reagent (40% hno3 with crystals of kclo3) for 3–7 hours. after the treatment in schulze’s reagent, cuticles were washed in water, subsequently immersed in 2% or 10% potassium hydroxide (koh) and finally rinsed in distilled water. some cuticles were stained with safranin, bismarck brown, malachite green or neu­ tral red (krings, 2000) for 1 to 2 hours to accentuate the anti­ clinal walls and stomata. before embedding in glycerine­gelatine slides, the cuticles were dehydrated in pure glycerine. 3. geological setting the intrasudetic basin, which is situated along the eastern mar­ gin of a suite of late palaeozoic bohemian continental basins (fig. 1), is the most important among the sudetic basins. struc­ turally, the intra­sudetic basin is a complicated nw–se­elon­ gated syncline with up to 5 km of infill that occupies an approximately 1800 km2 area, of which about one third is located in the territory of the czech republic (formerly czechoslovakia). de­ po sition spans a wide stratigraphic interval from the middle visean to the triassic and includes several hiatuses. continental depo sits unconformably overlie saxo­thuringian crystalline complexes of pre­cambrian to early palaeozoic age (tásler et al., 1979, bossowski, 1995). visean sediments in poland consist of a few kilometres of fluvial to alluvial-fan strata with interca­ lated marine to deltaic deposits. they are followed in poland by serpukhovian (early namurian) fluvial and coal-rich deposits of the wałbrzych formation. in bashkirian times, the depositional center enlarged further to the south along a tectonically active western basin margin. this resulted in deposition of the late bashkirian–early moscovian žacleř formation (yeadonian–bol­ sovian), with about 60–80 coal seams in three members. locally important coal seams of kasimovian – gzhelian (cantabrian to saberian) age occur only in the czech part of the basin in the odolov formation (svatoňovice and jivka members) (table 1). the stephanian/permian chvaleč formation is mostly com­ posed of coal-barren fluvial red beds and contains only one thin coal seam in the vernéřovice member. lacustrine horizons a few tens of metres thick, with bituminous limestones and shales are rarely intercalated in red beds (bečkov horizon). the overlying broumov formation contains the nowa ruda, olivětín and mar­ tínkovice members that correspond mostly to the asselian (opluštil et al. 2016). the nowa ruda member is formed mostly by thick complexes of rhyolite tuffs and tuffites, the olivětín member contains fossiliferous “walchia” shales several tens of metres thick and thin bituminous shales and ruprechtice and otovice limestones. the martínkovice member also contains limestone horizons, but only animal fossils have been discovered so far. the upper permian trutnov and bohuslavice formations are composed of red and brown mudstone and sandstone depo­ sits; and the middle triassic bohdašín formation is represented mostly by white sandstones. 4. systematics order cordaitanthales meyen, 1984 family cordaitanthaceae meyen, 1984 genus cordaites unger, 1850 type species cordaites borassifolius (sternberg) unger, 1850 as mentioned in the introduction, there are difficulties with the systematics of cordaites leaves. more than 40 cordaitalean spe­ cies have been described based on leaf adpressions from europe, table 1. stratigraphic table of the youngest part of the intrasudetic basin. adopted according to opluštil et al. (2016). remark: time intervals of gaps between younger units are not known. figure 1. map of the czech republic with permo-carboniferous basins and the studied locality. g eologia c roatica šimůnek zbyněk: revision of the genus cordaites unger from the permian of the intrasudetic basin (broumov formation, olivětín member, czech 165 defined on the shape, dimensions and venation type. even with complete, or nearly complete leaves, there can still be difficulties in classifying specimens to particular species, because the vena­ tion is often poorly preserved due to taphonomic processes (crookall, 1970). about 15 species of cordaites unger and poa-cordaites grand’eury ex brongniart have been described from the stephanian and permian, or reported from these strata. these species were compared with specimens found in the otovice lo­ calities but the latter are problematic because their cuticles are poorly preserved and so cannot be used in species determination. in both museums, seven fragments, probably belonging to four or five species, were selected for study. crookall (1970) only described five species from great britain. the last compre­ hensive paper on cordaitaleans was published by ledran (1966) who described 22 species from france. she also tried to describe the cuticles but they were usually poorly preserved and only in a few cases did they add significant information to sup­ plement the morphological description. barthel (1962, 1964) distinguished in cordaites principalis several types of cuticles and considered cordaites borassifolius, c. palmaeformis and c. principalis as indistinguishable from each other (barthel, 1976, 2009, 2016). specimens from the otovice locality demonstrate the vari­ ability in leaf shape, dimension and venation. here, comparison of these specimens will be made with other specimens described from the uppermost stephanian and permian. cordaites cf. beinertianus (göppert, 1841) grand’eury, 1877 (fig. 2a, h, i; pl. 1, figs. a, b) 1841 noeggerathia beinertiana göppert, vol. 5­6, p.108, pl. 12, fig. 3. 1877 cordaites beinertianus göppert; grand’eury, p. 215. 1914 dorycordaites beinertianus (göppert) grand’eury; bureau, p. 304, atlas, 1913, pl. 66, fig. 1. description: the leaf is lanceolate with a bluntly pointed apex. the fragment is 565 mm long and 97 mm wide. the venation is very fine and dense, 45–60 veins per cm in different parts of the leaf (fig. 2a, h, i; pl. 1, figs. a, b). remarks: the complete leaf may have been more than 600 mm long, and because its right margin is enrolled (fig. 2a), it could be 110–120 mm wide. the holotype of cordaites beinertianus (göppert, 1842) represents the basal half of a leaf. it is wedge­shaped, widening from 3 mm (base) to 55 mm (in the mid­ dle) along its length of 170 mm. the veins are very thin, and it seems from the picture that there are about 30 veins per cm. as the apex is not preserved, determination by means of venation only is uncertain. the type locality of cordaites beinertianus is the charlottenbrunn (nowadays jedlina zdrój), of poland and is probably bolsovian in age. this combination was used for the first time by grand’eury (1877) in comparison with cordaites affinis, but c. beinertianus was not formally transferred to the genus cordaites. grand’eury (1877) used this name without description, only with reference to (göppert, 1842). c. beinertianus was also reported from the upper stephanian (bureau, 1914), though it is not known that these young speci­ mens are of the same species as the holotype. this specimen is also similar to cordaites palmaeformis, however the lectotype represents several leaf fragments 160–180 mm long and 12–20 mm wide (šimůnek, 2015). other speci­ mens figured by göppert (1852) also do not have a preserved apex, which is an important diagnostic feature, but the leaves are wider, up to 50 mm wide. göppert (1852) did not specify the venation density; he only noted that the venation was fine and dense. only subsequent authors more precisely defined the vena­ tion density: geinitz (1855) – 3–4; weiss (1871) – 3–5 and zeiller (1886­1888) – 8–12 veins per mm. crookall (1970) mentioned 35–50 veins per mm. this confusion may be because each specimen came from a different country and stra­ tigraphy. the lectotype of cordaites palmaeformis came from the langsettian of wałbrzych in the intrasudetic basin (šimůnek, 2015), however the other syntype (göppert, 1852, pl. 16, fig. 2) is from the upper silesian basin. the leaves of cordaites palmaeformis are amphistomatic (šimůnek, 2015), with stomata on both cuticles arranged in rows. one cuti­ cle (probably adaxial) has 5–6 rows per mm, whilst the second cuticle (probably abaxial) has 12–16 rows per mm. these densi­ ties correspond to the densities of fine veins in the adpressions, and also correspond to the specimen from otovice. however, there is a large stratigraphic distance between these specimens, and cuticles from this specimen from otovice are not known. göppert (1852) compared cordaites palmaeformis with c. beinertianus. figure 2. shapes and venations of cordaites leaves: a. – cordaites cf. beinertianus, b. and c. –cordaites cf. affinis, d. and e. – cordaites sp. a; f. – cordaites cf. roesslerianus, g. – cordaites cf. foliolatus; scale bars: a = 5 cm; b–g = 2 cm. venations of leaves: h, i – cordaites cf. beinertianus (fig. a), j – cordaites cf. affinis (fig. b), k – cordaites sp. a (fig. d), l – cordaites cf. roesslerianus (fig. f ). (left scale bar is only for a; right upper scale bar is for b–g and left lower scale is for h–l). g eo lo gi a c ro at ic a geologia croatica 72/3166 cordaites cf. affinis grand’eury, 1877 (fig. 2b, c, j; pl. 1, fig. c–e; pl. 2) 1877 cordaites affinis grand`eury; grand`eury: p. 215–216, pl. xviii, figs 6. 7. 1896 cordaites (dorycordaites) affinis grand`eury; renault: p. 344, pl. lxxxvi, fig. 17. material: two specimens. national museum and museum of east bohemia (no. 74574). cuticle slides 698/1–16 have been prepared from specimen 74574. description: two incomplete leaves. the larger (pl. 1, fig. c) is 215 mm long and 36.5 mm wide. maximum leaf width is below its middle. the second specimen (pl. 1, fig. e) is a leaf fragment 165.5 mm long and 20.5 mm wide in its upper part. this leaf was probably thin and lacerated in its upper part. the venation is the same in both specimens, formed by very thin veins with density of 55 veins per cm. cuticles are very poorly preserved with details only visible by staining with safranin, malachite green or neutral red. it is dif­ ficult to distinguish adaxial and abaxial cuticles as both probably have stomatal rows and non­stomatiferous bands. cuticles on pl. 2, figs a, b come from the same leaf fragment and were stained in malachite green. pl. 2, fig. a probably represents an adaxial cuticle. dark bands 120–170 mm wide are distinguishable from light bands around 60 mm wide. pl. 2 fig. b probably belongs to an abaxial cuticle. the lighter bands on the adaxial cuticle prob­ ably correspond to stomatal rows on the abaxial cuticle and darker bands to non-stomatiferous bands (costal fields). abaxial cuticle (pl. 2, figs b–h). the cells are differentiated into 90–160 mm wide non­stomatiferous bands and 50–60 mm wide stomatal rows. in contrast to the adaxial cuticles, the stomatal rows are darker than the non­stomatiferous bands. the cells of the non­stomatiferous bands are oblong with straight or slightly bent walls, 15–22 mm wide and 45–80 mm long. the structure of the stomatal rows is difficult to observe. usually, there are 2 guard cells, 2 polar and 2 lateral subsidiary cells per stomatal complex. the stomatal complexes were probably collapsed and it is impos­ sible to distinguish cell walls from folds on the periclinal walls. in a few cases, guard cells have been preserved. they have a crescent shape, are 28–40 mm long and 12–14 mm wide (pl. 2, figs. e, f). remarks: grand`eury (1877) described similar speci­ mens with fine venation as cordaites affinis. they are narrow, lanceolate leaves with sharp apices, about 200–300 mm long and 18–30 mm wide. the widest part of the leaf is also approximately in the middle of the leaf. the dimensions of the leaves described here fit to this description, only they (pl. 1, fig. 3) are a little wider – 36.5 mm. the vein density is comparable with data from le­ dran (1966): 50–60 per mm. leaves of cordaites affinis start gradually to widen from their base, the leaf on pl. 1, fig. c widens more and thus resembles more closely cordaites palmaeformis that is compared closely with previous species. cuticles prepared from the specimen on pl. 1, fig. c resemble the cuticles of cordaites palmaeformis (šimůnek, 2015) with stomatal rows on both the abaxial and adaxial cuticles. cuticles from the type material of cordaites palmaeformis were also poorly preserved, however, the structure of the stomatal complexes of adaxial and abaxial cuticles has eventually been resolved. cordaites cf. affinis from otovice and cordaites palmaeformis from walbrzych are both amphistomatic leaves with stomata arranged in stomatal rows on both cuticles. however, it is still not possible to demonstrate that the specimen on pl. 1, fig. c is cordaites affinis, or if it belongs to cordaites palmaeformis, because cells of the sto­ matal rows are poorly preserved and a comparison is not possible, therefore these specimens are named as cordaites cf. affinis. ledran (1960, 1966) studied cuticles from cordaitaleans from france which were also poorly preserved. her drawings of the cuticles show that the stomatal complexes are drawn as cy­ clocytic complexes with 4 or 5 equal subsidiary cells around the stomatal pore. such a stomatal type is not known from cordaita­ leans. abaxial cuticles of cordaites angulosostriatus also have stomatal rows (ledran, 1960, 1966). its reconstruction by rabitz (1966) is more realistic. the adaxial cuticle of cordaites angulosostriatus has dispersed stomatal complexes. barthel (1964) published cordaites sp. type 4 from the asturian of zwickau that also has dark stomatal rows on abaxial cuticles and dispersed stomata on adaxial cuticles. cordaites regularis described by ledran (1966) has stomatal rows on the abaxial cuticle and dispersed stomata on the adaxial cuticle. cu­ ticles from the other nine cordaitalean species described by le­ dran (1966) have either stomatiferous bands or irregular sto­ matal rows on the abaxial cuticles. several cordaitalean species have been described that have stomatal rows on the abaxial and adaxial cuticles: e.g. cordaites principalis type 2 zodrow et al. (2000) from the bolsovian of bay st. george, newfoundland, canada (see also šimůnek, 2007). similar cuticles are also known from the bolsovian of the czech republic – cordaites rerichensis (šimůnek, 2007) and from the asturian of the heřmanova huť locality – cordaites pilsensis (šimůnek, 2007, 2008) and from the blažkovice locality – cordaites blazkovicensis šimůnek, 2007; however, these spe­ cies have a “cordaites principalis­type” venation (šimůnek, 2007, 2008). the stephanian species cordaites risutensis šimůnek, 2007 is similar to cordaites cf. affinis having fine venation with 50–60 veins per cm, however the stomatal densities within the stomatal rows are not so high and individual stomatal complexes are separated by ordinary epidermal cells. the last comparable species is cordaites radvanicensis šimůnek, 2007 from the stephanian of the intrasudetic basin, czech republic. the type material consists of leaves less than 30 mm wide with a venation consisting of 30 thick veins per mm and 2–3 thin sclerotic bundles between each of the two thick veins. however, the “thick” veins are not as thick as those in cordaites principalis. when we count all the veins, there are 90 veins per cm. a comparison of the cuticles is interesting: it was demonstrated in cordaites radvanicensis that on the adaxial cuticle there are dark stomatiferous bands 120–160 mm wide, separated by light non­stomatiferous bands 60–80 mm wide. the dark stomatal rows of the abaxial cu­ ticles are 50–70 mm wide and are separated by 50–80 mm wide non–stomatiferous bands. the data from the abaxial cuticle do not fully compare with cordaites cf. affinis, but dark bands on the adaxial and abaxial cuticles are common for both species. it is pos­ sible that the specimen from otovice, černý potok, belongs to cordaites radvanicensis šimůnek, 2007. the guard cells of cordaites cf. affinis are 28–40 mm long and the guard cells of cordaites radvanicensis are 25–38 mm long (šimůnek, 2007). cordaites cf. roesslerianus geinitz, 1862 (fig. 2f, l; pl. 3, figs. d–f) 1862 cordaites roesslerianus n. sp.; geinitz: p. 149, pl. 35, fig. 5. material: museum of east bohemia, hradec králové, specimen no. 74575. description: the leaf fragment is 71.5 mm long and 15 mm wide; the margins are non­parallel, but the base and apex not preserved. g eologia c roatica šimůnek zbyněk: revision of the genus cordaites unger from the permian of the intrasudetic basin (broumov formation, olivětín member, czech 167 the venation differs from all previously mentioned species. the leaf relief is three­dimensional with prominent ribs and grooves that make prominent veins in oblique light; vein density 20 per cm of the leaf (pl. 3, fig. e). thin veins were not observed. remarks: the incomplete nature of the specimen renders the correct determination problematical. cordaites roesslerianus geinitz are also preserved in fragments up to 120 mm long and 15–20 mm wide is similar. according to geinitz (1862), the vein density is 20–22 veins per cm. cuticle macerations of cordaites cf. roesslerianus were unsuccessful, with only the dark and light bands being discernible (pl. 3, fig. f). further macera­ tion resulted in destruction of the cuticles. the dark bands that probably reflect vascular bundles are 370–500 mm wide and the light bands are only 170–300 mm wide. no sclerotic (thin) bun­ dles were observed. the other comparable species is cordaites principalis (germar) geinitz. its holotype is preserved as a bunch of 32 leaves, 350–410 mm long and 15–36 mm wide. the leaf mar­ gins are slightly bent, as in the currently described specimen. the vein density of cordaites principalis is 20–25 veins per cm (šimůnek, 2015), which is also in concordance with the pre­ sently described specimen. however, the ridges in cordaites principalis are more prominent and the places between the ridges are flatter. perhaps c. roesslerianus is conspecific with c. principalis, however it is difficult to prove because the base and apex of c. roesslerianus is not preserved. lipps (1927) described cordaites principalis from the lower permian of the intrasudetic basin (unislaw ślaski locality). it has 18–24 veins per cm an 3–4 sclerotic bundles between 2 veins. cordaites cf. foliolatus grand’eury (fig. 2g; pl. 3, fig. g) 1877 cordaites foliolatus grand`eury; grand`eury: p. 219, pl. xxi, fig. 3 material: a single specimen from the otovice locality is stored in the national museum, prague. description: the leaf is small, narrow, 69.5 mm long and 13 mm wide. the base is 9 mm wide. the apex is blunt. the venation is not prominent, fine, about 40 veins per cm. remarks: this specimen to some extent resembles cordaites foliolatus grand`eury. proportionally, the specimen from the otovice is much more slender than the grand’eury type specimens of cordaites foliolatus, which have a narrower base (5–7 mm) and wider leaves (10–25 mm). length/width ratio of this specimen is 5.4, whereas in grand’eury’s specimens it is around 4, and the apex is blunt to rounded, and the venation is prominent with 30 veins per cm and 4–6 sclerotic bundles be­ tween each pair of veins. it is also possible that the described specimen represents a juvenile leaf of some long-leaved form, therefore it is described here as cordaites cf. foliolatus grand’eury. cordaites sp. a (fig. 2d, e; pl. 3, figs. a-c) material: two fragments, stored in the national museum, prague. one represents the basal part and the other an apical part. they probably come from different leaves but may belong to one species. description: the fragment from the basal part of a leaf is 51 mm long and only 12 mm wide near the base. the leaf widens rela­ tively progressively from the base. the second fragment repre­ sents a terminal part of a leaf. it is widest in the middle – about 28 mm and suddenly narrowed to the bluntly pointed apex. the venation is fine, but not dense, about 25 veins per cm of the leaf. remarks: these specimens are difficult to compare with european cordaites species. the estimated length of this leaf is 120–130 mm. the small­leaved forms described by grand’eury (1877) and ledran (1966) are usually wider and have a blunt or rounded apex. meyen (1966) described some similar forms as rufloria meyen. some species have a large variability, mostly also with rounded apices, but there were other forms with nearly bluntly pointed apices. however, the venation of rufloria is quite different from cordaites species. the shape of the leaf is to some extant similar to cordaites laevis (grand’eury, 1877, pl. 25, fig. 2), which represents a drawing of a twig with leaves and fructifications. some leaves have blunt apices but others have bluntly pointed apices. cordaites laevis is maybe a nomen nudum, because grand’eury (1877) wrote only that the twig is with cordaites laevis leaves and antholithes fructifications. there was no description of the holotype, but the drawing of grand’eury (1877) was illustrated many times in subsequent publications and also on the internet. 5. discussion it is difficult to classify euramerican cordaitaleans only by mac­ romorphological characteristics because of the variability of the leaves; e.g. ignatiev & meyen (1989, fig. 6) showed great variability of rufloria synensis. similar leaves in the eurameri­ can realm could be classified to several species, if we only take into account leaf shape. however, when studying cordaitaleans from one locality, we do not have such variability, e.g. in the case of cordaites borassifolius (šimůnek et al, 2009): the length of complete leaves is about 400–700 mm and width 35–90 cm, but the leaf shape remains practically the same. unfortunately, the localities near otovice yielded specimens, where cuticular study was mostly not possible, so we are reliant on morphological features of cordaitalean leaves only. still, it is not clear, if four or five cordaites species are present in the oto­ vice localities. in this paper, five species are described, but it can­ not be excluded that the specimens described here as cordaites cf. beinertianus and c. cf. affinis do not belong to one species. the other species have different types of venation and cordaites cf. foliolatus is small with a somewhat different leaf shape. crookall (1970) and barthel (1976) realised the dif­ ficulty in the determination of cordaites species. crookall (1970) used the names of species, but barthel (1976) consi­ dered all species (e.g. cordaites borassifolius, c. principalis and c. palmaeformis) as “one” species, even if diversity of the cuti­ cles was much higher, and barthel (1976) and in subsequent papers (e.g. barthel, 2009, 2016) preferred using “cordaites sp.”. ragot (1966) studied many french species of stephanian and permian age, but cordaites cuticles were poorly preserved and did not contribute to the identification of individual species. due to their variability in leaves and venation all species in this paper are determined with some uncertainty as “cf.”, even if it is evident that more cordaites species also occur in the eurameri­ can permian (asselian). 6. floral assemblage with cordaites the flora of the olivětín member has been neglected in the palaeo­ botanical literature. except for museum collections, there are un­ published works by rieger (1966) and bors (1988). a taxo­ nomic list compiled from these works and museum collections consists of: sigillaria brardii brongniart, calamites gigas g eo lo gi a c ro at ic a geologia croatica 72/3168 brongniart, palaeostachya thuringiaca (weiss) bar­ thel, cyathocarpus cyatheus (brongniart) mosbrug­ ger, “pecopteris” thuringiaca němejc, autunia conferta (sternberg) kerp, a. naumannii (gutbier) kerp, arnhardtia scheibei (gothan) haubold et kerp, sphenopteris germanica weiss, odontopteris lingulata (göppert) schimper, o. subcrenulata rost, neurodontopteris auriculata (brongniart) potonié, barthelopteris germarii (giebel) zodrow & cleal, taeniopteris coriacea göppert, t. cf. multinervia weiss, ernestiodendron filiciforme (schlotheim ex sternberg) florin, culmitzschia angustifolia (flo rin) clement­westerhof, c. parvifolia (florin) clement ­ ­westerhof, c. intermedia (florin) clement­wes­ terhof, c. speciosa (florin) clement­westerhof, hermitia goeppertiana (florin) clement­westerhof, h. hirmeri (florin) clement­westerhof, otovicia hypnoides (brongniart) kerp et al., walchia piniformis schlotheim ex sternberg and gomphostrobus bifidus geinitz. this assemblage, which has been collected for more than 100 years, consists mainly of mesophilous to xerophilus elements. the hygrophilous species are practically limited to sigillaria brardii and pecopteroids, which occur only very rarely. walchian conifers dominate in the “walchia shales” and autunia conferta is the most common species in the limestone facies. the other species occur partly in limestone and partly in the “walchia shales”. 7. conclusion cordaitaleans are not very common in the permian of the intra­ sudetic basin. seven specimens studied from the museum collec­ tions represent four or five species. the first specimen has been classified as cordaites cf. beine rtianus. the type material of cordaites beinertianus has a simi­ lar leaf shape, but the veins are sparser than in c. cf. beinertianus. the leaves of c. cf. beinertianus also resemble cordaites palmaeformis, which has slightly narrower leaves but a comparable vein density. a further two specimens were classified as cordaites cf. affinis. they have a comparable shape and venation with the type material of cordaites affinis grand’eury. however, the apex is not preserved, so a comparison of this feature is not possible. one specimen, from which the cuticles have been studied, is wider than typical c. affinis and could also be compared with c. beinertianus. the cuticles of cordaites cf. affinis are poorly pre­ served, but stomatal rows and non­stomatiferous bands are dis­ tinguishable on both cuticles. the same cuticular type also occurs in cordaites palmaeformis, and also c. radvanicensis, which is known from the stephanian of the intrasudetic basin, but unfor­ tunately only as fragments. the second specimen of cordaites cf. affinis is narrow and compares well with the variability of cordaites affinis. on the other hand, cordaites palmaeformis can also have narrow leaves and all specimens mentioned here could represent the variability of one species similar to cordaites palmaeformis or c. beinertianus. the next specimen has been classified as cordaites cf. roesslerianus. the determination is difficult because the base and apex are not preserved, however, the venation is very typical with wide and sparse veins. such a venation is known from cordaites roesslerianus and c. principalis. another specimen has been classified as cordaites cf. foliolatus. it resembles the type specimens of that species, however, it has somewhat narrower leaves. it is the smallest cordaitalean leaf from the otovice locality and could simply represent a juve­ nile leaf of one of the other species. the final species is represented by two fragments: a basal and an apical part. it is a relatively short and wide leaf that is dif­ ficult to compare with any figured specimens, therefore it is named here as cordaites sp. a. it resembles some leaves drawn by grand’eury (1877) as cordaites laevis, but there is nei­ ther description nor diagnosis for this species, so it must be con­ sidered as a nomen nudum. the venation of cordaites sp. a dif­ fers from the venation of the previously mentioned specimens and therefore must belong to a different species. acknowledgement the author thanks s. štamberg from the museum of east bohemia in hradec králové and m. libertín from the na­ tional museum in prague for enabling the study of the collections from the intrasudetic basin. thanks are also due to c. j. cleal from cardiff uk for english checking and two anonymous re­ viewers for their reviews. this work was subsidised by the grant 2017/26/m/st10/00646 (polish national science centre). references barthel, m. (1962): zur kenntnis inkohlter blätter der gattung cordaites presl.– hallesches jahrbuch für mitteldeutsche. erdgeschichte, 4, 37–39. barthel, m. (1964): coniferen­ und cordaiten­reste aus dem rotliegenden des döh­ lener beckens.– geologie, 13/1, 60–89. barthel, m. (1976): die rotliegendflora sachsens.– abhandlungen des staatlichen museums für mineralogie und geologie dresden, 24, 1–190, dresden. barthel, m. (2009): die rotliegendflora des thüringer waldes.– veröffentlichungen naturhistorisches museum schleusingen, sonderveröffentlichung 2009 (zusammendruck von kapiteln aus den jahrgängen 2003 – 2008). schleusingen. barthel, m. (2016): die rotliegendflora der döhlen-formation.– geologica saxo­ nica, 61(2), 105–238. bors, m. (1988): litofaciální a biofaciální analýza svrchních olivětínských vrstev na broumovsku.– dipl. thesis, přírodovědecká fakulta uk, 67 p. praha. bossowski, a. (1995): lower silesian coal basin.– in: zdanowski, a. & żakowa, h. (eds.): the carboniferous system in poland.– prace panstwowego instytuta geologicznego, 148, 173‒175. bureau, e. (1914): études des gîtes minéraux de la france, bassin houiller de la basse loire: paris, ministère des travaux publics, v. 1, 433 p. (1910); v 2, 417 p.; atlas, 80 pls. (1914). crookall, r. (1970): fossil plants of the carboniferous rocks of great britain.– memoirs of the geological survey of great britain 2nd sect., palaeontology, 4/6, 793–840. florin, r. (1931): untersuchungen zur stammesgeschichte der coniferales und cordaitales.– kunglige svenska vetenskapsakademiens handlingar, ser. iii, 10/1, 588 p. geinitz, h.b. (1855): die versteinerungen der steinkohlenformation in sachsen. verlag w. engelmann, leipzig, 61 p. geinitz, h.b. (1862): dyas oder die zechsteinformation und das rotliegende. ii. die pflanzen der dyas und geologisches. verlag w. engelmann, leipzig, 342 p. göppert, h.r. (1841-1846): die gattungen der fossiler pflanzen.– verlag von henry und geben, bonn, p. 1–70, pls. 1–18 (1841); p. 71–118, pls. 1–18 (1842); p. 119–154, pls. 1–20 (1846). göppert, h.r. (1852): fossile flora des übergangsgebirges.– verhandlungen der kaiserlichen leopoldinisch­carolinischen akademie der naturforscher, suppl. des 22 bd. 1–299, taf. 1–44, breslau und bonn. göppert, h.r. (1864­1865): die fossile flora der permischen formation.– palaeonto­ graphica, 12: 1–224, pls. 1–40 (1864); 12: 225–316, pls. 41–64 (1865). cassel. grand’eury, c.f. (1877). flore carbonifėre du départment de la loire et du centre de la france. – prémiere partie­botanique impemerie nationale, paris, 624 p. ignatiev, i.a. & mejen, s.v. (1989): suchoviella – gen. nov. from the permian of angaraland and review of the systematics of cordaitanthales.– review of palaeo­ botany and palynology, 57, 313–339. kerp, h. (1990): the study of fossil gymnosperms by means of cuticular analysis.– palaios, 5, 548–569. g eologia c roatica šimůnek zbyněk: revision of the genus cordaites unger from the permian of the intrasudetic basin (broumov formation, olivětín member, czech 169 kerp, h. & krings, m. (1999): light microscopy of cuticles. – in: jones, t.p., rowe, n.p. (eds.): fossil plants and spores: modern techniques.– geological society, london, 52–56. krings, m. (2000): the use of biological stains in the analysis of late palaeozoic pte­ ridosperm cuticles.– review of palaeobotany and palynology, 108, 143–150. krings, m. & kerp, h. (1997): an improved method for obtaining large pterido­ sperm cuticles.– review of palaeobotany and palynology, 96, 453–456. ledran, c. (1960): sur les cuticules de cordaїtales.– bulletin de la société géologique de france 7e série, t. ii, 653–656. ledran, c. (1966): contributions a l´étude des feuilles de cordaitales.– théses présentées a la faculté des sciences de l´académie de reims, sér. 1, 1–154. reims. lipps, t. (1927): zur rotliegendflora von langwaltersdorf (niederschlesien).– jahr­ buch der preußischen geologischen landesanstalt, 48, 567–592. meyen, s.v. (1966): kordaitovye verchnego paleozoja severnoj evrazii [cordaiteans of the upper palaeozoic of north eurasia].– trudy geologicheskogo instituta akademii. nauk sssr, 150, 5–184. meyen, s.v. (1984): basic features of gymnosperm systematics and phylogeny as shown by the fossil record.– botanical review, 50/1, 1–111. opluštil, s., schmitz, m.s., kachlík, v. & štamberg, s. (2016): rea­ ssessment of lithostratigraphy, biostratigraphy, and volcanic activity of the late palaeozoic intra-sudetic, krkonoše-piedmont and mnichovo hradiště basins (czech republic) based on new u­pb ca­id­tims ages.– bulletin of geoscien­ ces, 91/2, 399–432. rabitz, g. (1966): cordaiten aus dem flotzführenden oberkarbon des ruhrgebiets. – fortschritte der geologie rheinland und westfalen, 13, 303–316. renault, b. (1896): bassin houiller et permien d´autun et d´épinac, flore fossile, 1, in: études des gîtes mineraux de la france, iv, imprimerie nationale, 578 p., atlas 1893, pls. 29– 89. paris. rieger, z. (1966): fytopaleontologický výzkum broumovského permu. – in tásler, r. základní geologický výzkum broumovského permu.– ms. geofond, 33 p., pra­ ha. šimůnek, z. (2007): new classification of the genus cordaites from the carbonife­ rous and permian of the bohemian massif, based on cuticle micromorphology.– acta musei nationalis pragae, series b, historia naturalis, 62/3–4, 97–210, šimůnek, z. (2008): the asturian and cantabrian floral assemblages with cordaites from the plzeň basin (czech republic).– studia geologica polonica, 129, 51–80. šimůnek, z. (2015): cuticles of the polish type material of cordaites palmaeformis (göppert) weiss and a cordaites principalis­like form from germany, pennsylva­ nian.– review of palaeobotany and palynology, 223, 50–70. šimůnek, z., opluštil, s. & drábková, j. (2009): cordaites borassifolius (sternberg) unger (cordaitales) from the radnice basin (bolsovian, czech re­ public).– bulletin of geosciences, 84/2, 301–336. tásler, r., čadková, z., dvořák, j., fediuk, f., chaloupský, j., je­ tel, j., kaiserová-kalibová, m., prouza, v., schovánková­ -hrdličková, d., středa, j., střída, m. & šetlík, j. (1979): geo­ logy of the bohemian part of the intra­sudetic basin. 296 p.– academia, praha. [in czech with english summary] unger, f. (1950): genera et species plantarum fossilium.– wilhelm braunmüller, 627 p., wien. weiss, c.e. (1869-72): fossile flora der jüngsten steinkohlenformation und des rot­ liegenden im saar­rhein­gebiete.– verlag a. henry, 250 p., 20 pls., bonn. zeiller, r. (1886­88): flore fossile du bassin houiller de valencienes.– études gîtes minéraux france, 1–731 (text 1888), pls. 1–94 (atlas 1886). paris. zodrow, e.l., šimůnek, z. & bashforth, a.r. (2000): new cuticular mor­ photypes of „cordaites principalis (germar) geinitz” from the canadian carboniferous maritimes basin.– canadian journal of botany, 78/2, 135–148. g eo lo gi a c ro at ic a geologia croatica 72/3170 plate 1 a – cordaites cf. beinertianus (göppert) grand’eury, coll. national museum, prague, no. e 7601, scale bar = 5 cm. b – venation of the leaf from fig. a., scale bar = 2 mm c – a leaf of cordaites cf. affinis grand’eury, coll. museum of eastern bohemia, hradec králové, no. 74574, scale bar = 2 cm d – venation of the leaf from fig. c., scale bar = 2 mm e – a leaf of cordaites cf. affinis grand’eury, coll. national museum, prague, no. e 7601, scale bar = 2 cm f – venation of the leaf from fig. e., scale bar = 2 mm g eologia c roatica šimůnek zbyněk: revision of the genus cordaites unger from the permian of the intrasudetic basin (broumov formation, olivětín member, czech 171 plate 2 cuticles of cordaites cf. affinis grand’eury from the leaf figured on pl. 1, fig. c. a – b adaxial and abaxial cuticle from the same leaf fragment. slide 698/13, scale bar = 200 mm. c – h abaxial cuticles. c. detail from fig. b. with two stomatal rows and non-stomatiferous bands. scale bar = 100 mm. d. abaxial cuticle with many stomatal rows. slide 698/15, scale bar = 200 mm. e. close up of fig. d. with guard cells (arrow). scale bar = 100 mm. f. close up of two guard cells from fig. e. scale bar = 50 mm. g – h two stomatal rows and a non-stomatiferous band, slides. g. 698/7; h. 698/14, scale bar = 50 mm. g eo lo gi a c ro at ic a geologia croatica 72/3172 plate 3 a – c cordaites sp. a; a. terminal part of the leaf, b. basal part of the leaf, coll. national museum, prague, no. e 7602 and e 7603, (a and b – scale bar = 1 cm), c. close up of the venation, scale bar = 2 mm. d – f cordaites cf. roesslerianus geinitz. d. fragment of the leaf, coll. museum of eastern bohemia, hradec králové, no. 74575, scale bar = 1 cm, e. close up of the venation, scale bar = 2 mm, f. macerated leaf fragment with veins (vascular bundles) and tissue between them. slide 700/3, scale bar = 500 mm. g cordaites cf. foliolatus grand’eury, coll. national museum, prague, no. e 7599, scale bar = 1 cm. 2021 | 74/2 | 189–208 | 14 figs. | 2 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction ground shaking during an earthquake usually causes major dama ge to structures. however, earthquakes also induce ground failures that can significantly contribute to total earthquake loss. “the term ground failure is a general reference to landslides, liquefaction, lateral spreads, and any other consequence of shaking that affects the stability of the ground” (usgs earthquake glossary, 2021). unfortunately, numerous cases worldwide witness that not enough attention is directed toward the identification of various types of ground failure which usually follow very strong or severe earthquakes (bird & bommer, 2004). the absence of ground failure data may lead to unrealistic projections of losses caused by a particular earthquake. furthermore, evidence of such processes/phenomena represent an important input into the production of reliable susceptibility maps and microzoning, which are important in the proper evaluation of seismic hazard in a particular region. most of such databases in the literature are related to landslides (keefer, 1984; rodríguez et al., the preliminary inventory of coseismic ground failures related to december 2020 – january 2021 petrinja earthquake series davor pollak1,*, vlatko gulam1, tomislav novosel1, radovan avanić2, bruno tomljenović3, nina hećej1, josip terzić1, josip stipčević4, mario bačić6, tomislav kurečić2, mario dolić1, iris bostjančić1, lara wacha2, ivan kosović1, marko budić2, matija vukovski2, nikola belić2, marko špelić2, vlatko brčić2, josip barbača2, branko kordić2, damir palenik2, radovan filjak2, tihomir frangen1, mirja pavić1, kosta urumović1, marin sečanj7, bojan matoš3, marin govorčin5, meho saša kovačević6 and lovorka librić6 1 croatian geological survey, department of hydrogeology and engineering geology, 10 000 zagreb, croatia; (*corresponding author: dpollak@hgi-cgs.hr) 2 croatian geological survey, department of geology, 10 000 zagreb, croatia 3 university of zagreb, faculty of mining, geology and petroleum engineering, department of geology and geological engineering, 10 000 zagreb, croatia 4 university of zagreb, faculty of science, department of geophysics, 10 000 zagreb, croatia 5 university of zagreb, faculty of geodesy, 10 000 zagreb, croatia 6 university of zagreb, faculty of civil engineering, department of geotechnical engineering, 10 000 zagreb, croatia 7 independent researcher, katarine zrinski 6, 10370 dugo selo, croatia doi: 10.4154/gc.2021.08 abstract the most recent major earthquake series struck near petrinja (december 29th 2020 m 6.2), and triggered extensive ground failures in the wider area of petrinja, sisak and glina. coseismic ground failures including subsidence dolines, liquefaction and landslides have been documented over a large area by various experts and teams. these data are stored in the newly created inventory, which is openly presented in this paper. this inventory is administered and updated by the croatian geological survey, and will be available online via a web map service (wms) (www.hgi-cgs.hr). the aim of the inventory is to not only provide data for the development of susceptibility maps and more detailed exploration for possible remediation measures, but also to define the priorities for immediate action. the earthquake triggered the rapid development of dropout dolines which endanger the local populations of the villages of mečenčani and borojevići. this is still an ongoing process in the vicinity of the houses and therefore in-situ exploration started immediately. liquefaction related to alluvial sediments of the sava, kupa and glina rivers occurred almost exclusively in loose and pure sands, and was accompanied by sand boils, subsidence and lateral spreading. liquefaction also presents a greater hazard because settlement of houses and river embankments occurred. lateral spreading caused failures of river flood embankments and natural river banks. according to the data known to date, the majority of the coseismic landslides were reactivated with minor displacements. despite that, it has been recognised that houses at the edge, or in landslide colluvium suffered greater damage than other houses located outside the landslide impact zone. 1999, bommer & rodríguez, 2002; gorum et al., 2011) or liquefaction (youd & hoose, 1978), but there are also more recent examples of inventories comprising all the typical forms of ground failure caused by earthquakes (prestininzi & romeo, 2000). it is well known that croatia lies in a seismically active region of the central mediterranean, characterized by seismicity that is unevenly distributed across the country, both in the adriatic (herak et al., 2005; herak et al., 2017b; govorčin et al., 2020) and in the pannonian basin area (herak et al., 2009; herak et al., 2020; markušić et al., 2020). historical and instrumentally recorded data indicate the three most seismically active areas are: nw croatia (greater zagreb area), the croatian primorje (greater rijeka area) and dalmatia. they are clearly distinguished on the seismic hazard map for the republic of croatia (herak et al., 2011) (figure 1). since the largest city in croatia is also situated in a seismically active area, the group of authors have created a database of geotechnical boreholes which contains relevant data for soil behaviour and site response analyarticle history: manuscript received january 26, 2021 revised manuscript accepted march 01, 2021 available online may 06, 2021 keywords: petrinja, earthquake, ground failures, inventory, dropout dolines, liquefaction, landslides g eo lo gi a c ro at ic a geologia croatica 74/2190 ses for the city of zagreb (kvasnička et al., 1998; kvasnička & matešić, 2001; matešić & kvasnička, 2007; matešić et al., 2011). although there have been a number of ml ≥ 6.0 earthquakes registered in the last millennium, historical data about earthquake-triggered ground failures in croatia are scarce and incomplete. as a result, such an inventory does not yet exist. however, the most recent december 29th 2020 m 6.2 earthquake near petrinja, which together with the foreshock on december 28 ( m 5.0) and the following aftershock series that is still ongoing, triggered extensive coseismic ground failures and initiated the creation of such inventory. therefore, the focus of this work is to present the structure of the initial inventory and data on coseismic ground failures collected during first two weeks of the petrinja earthquake series after the main shock of m 6.2 that occurred on 29th december 2020. the work also indicates the most affected zones, and provide information to a wider audience, the general public, local and regional administrations and civil protection for further reference. we also hope that open access to the collected data will motivate other earth-scientists, experts, and the public to provide their contribution to the database, in order to establish the most complete insight into all coseismic ground failures and processes triggered by the petrinja earthquake series. the database would also enable more realistic estimations of the total earthquake damage and loss. for this reason, the complete table of inputs collected so far is presented here in order to transparently provide information that can be further used to develop susceptibility maps, identify the most critical surface damage zones and ensure data for seismic microzoning and hazard assessment. detected coseismic ground failures will be additionally explored in much more detail to provide better insights into local conditions, triggering forces and failure mechanisms, in order to provide parameters for possible remediation measures. the database can also serve as a valu able factor in the development of the design and construction policies for the rehabilitation of the buildings and infrastructure in the area, thus ensuring the long-term safety of residents. the data presented in this preliminary inventory was mainly collected by geologists from the croatian geological survey (hgi), supplemented by inputs from other earth-scientists and geotechnical engineers from the university of zagreb (the faculty of mining, geology & petroleum engineering and the faculty of science; faculty of civil engineering), other civil engineering experts, local citizens and the media. therefore, it is important to point out that not all of the entries presented here are verified yet by geologists. in addition, the inventory for this particular earthquake series should be considered as preliminary, since we expect that additional data will be collected over time. the up to date database is presented online via web map service (wms), and will be continuously maintained and updated by the hgi (www.hgi-cgs.hr). 2. overview of geology and seismicity of the research area 2.1. geology the petrinja earthquake series (december 2020 – january 2021) took place along the southwestern margin of the sava basin of the pannonian basin system (pavelić & kovačić, 2018, saftić et al. 2003 with references). a simplified geological map of the earthquake series affected area (the research area) is shown figure 1. the location of croatia marked blue on the european map (right). geographical location of the research area (red rectangle) at the seismic hazard map for the republic of croatia (herak et al., 2011). red symbol indicates the location of the earthquake epicentre (29.12.2020). map shows peak ground acceleration (pga) for 10 % probability of exceedance in 50 years in units of standard gravity (g) for reference rock soil (vs30 = 800 m/s). this corresponds to pga-values that return on average every 475 years. g eologia c roatica pollak et al.: the preliminary inventory of coseismic ground failures related to december 2020 – january 2021 petrinja earthquake series 191 figure 2. the geological map of the research area (originally in the scale 1:100.000) with the locations of ground failures. g eo lo gi a c ro at ic a geologia croatica 74/2192 on figure 2, modified after the basic geological map of sfry 1:100.000, sheet sisak (pikija, 1987) and the basic geological map of the republic of croatia 1:100.000, sheet bosanski novi (šikić, 2014a). the research area is mainly covered by neogene and quaternary deposits, while older pre-neogene basement rocks (mostly palaeogene) are only locally exposed in the se part of the area (pikija, 1987). in the following text we shall briefly describe the major characteristics of the stratigraphic units presented on the map (figure 2). some more details are presented for units that are subjected to ground failure. the oldest exposed rocks in the research area are of middle to late jurassic age (j2,3), represented by metasandstones, slates, phyllites, marbles and greenschists, as well as by metamorphosed magmatic rocks (šikić, 2014b, raffaelli & magdalenić, 1970; majer, 1984; majer & lugović, 1985). the thickness of this unit is up to 400 m (šikić, 2014a). small outcrops of the cretaceous sedimentary sequence (late senonian – k2 3) consist of limestones with pyroclastics and radiolarian chert intercalations. palaeogene deposits (palaeocene-eocene – pc, e) are mainly conglomerates (figure 2). the conglomerates are carbonate-free, polymictic with various amounts of sandy matrix. along with conglomerates, intercalations of sandstones, shales and coal seams, marls and limestones are present. an estimated thickness of these deposits is around 200 m (šikić, 2014b). ottnangian deposits (m2) are mostly represented by coarse and fine-grained clastics (šikić, 2014b). conglomerates, gravels and sands are mostly seen in the lower part of the sequence, while the upper part is composed of an alternation of marls, clays and limestones. the thickness of the ottnangian clastics is assumed to be 250-300 m. between the river kupa in the northwest and mečenčani village in the southeast (figure 2), badenian deposits (m4) are exposed. they unconformably rest over palaeogene and ottnangian sediments, above distinctly recognized erosional boundary. in the basal part they are represented by conglomerates, gravels, sandstones and biocalcarenites that grade upward into finergrained clays and marls, and into bioclastic and biogenic limestones in the uppermost part of the sequence (pikija, 1986; šikić, 2014b). the thickness of badenian sediments is variable, reaching up to 300 m. sarmatian deposits (m5) continuously follow on top of badenian deposits. they began with coarse-grained clastics composed of polymictic conglomerates, gravels, sandstones, sandy clays and marls deposited in coastal environments (šikić, 2014b). in deep-water environments of the basin, laminated sands, marls, and limestones prevail. the thickness of the sarmatian deposits is a maximum of 100 m. pannonian clastics (m6) are divided into the lower and middle pannonian. the most frequent sediments of the lower pannonian are laminated and platy limestones (micrites and clayey micrites), of the croatica formation, locally interlayered with sands and sandy-marls, and with local occurrences of cm-thick gravel interlayers (šikić, 2014b). in the glina and zrin-dvor valleys, middle pannonian, laminated to thin-layered sands and sandy marls alternate with clayey limestones, and poorly lithified sandstones. the croatica fm. is followed by the medvedski breg fm., which is represented by massive to weakly layered marls and sporadic clayey limestones and clays. sediments of the medvedski breg fm. are deposited in the more distal part of the lacustrine basin (avanić et al., 2018b). the thickness of the pannonian deposits is between 120 to 200 m. pontian deposits (m7) are mostly characterized by marls. in the lower part, clayey and sandy marls predominate, while in the upper part, clayey siltstones and sands prevail (šikić, 2014b). in the area of the glina river, layers of coal-clay seams and interlayers of lignite are found. according to the latest lithostratigraphic nomenclature, pontian deposits are subdivided into the andraševec and hum zabočki formations, based on a subdivision known in the area of northern croatia (kovačić, 2004; grizelj, 2004). the andraševec formation is composed of the alternation of sands, calcite-rich silts and marls, deposited since the late pannonian to the late pontian (avanić et al., 2018a). it is continuously overlain by the hum zabočki formation of the late pontian that mostly consists of fineto medium-grained sands, silty marls, clays and coal seams (cm to dm thick). the thickness of the pontian deposits varies between 150 to 450 m. pliocene deposits (pl) are composed of coarseto fine-grained clastics , mostly sands, gravels, silts and clays with a general coarsening upwards trend from the lower to upper viviparus beds (mandic et al., 2015; kurečić, 2017; kurečić et al., submitted) (figure 2). lignite layers are also common. pliocene sediments are equivalent to the vrbova fm. of the sava basin (avanić et al., 2018a; halamić et al., 2019), subdivided into five lithofacies units: massive and normally graduated gravels, cross stratified sands and gravelly sands, massive and laminated sands, clay silts and heterolithic facies (kurečić, 2017). sandstones (lithoarenites) are limonitized and form thin interlayers within the sand the thickness of the pliocene deposits is 200-400 m (pikija, 1986). plio-quaternary clastics (pl, q) unconformably cover various older deposits, from jurassic to pontian ages (figure 2). they consist of sands, gravels and clays, rarely siltites, conglomerates, sandstones, and coal-clays and coal interlayers (šikić, 2014b; pikija, 1986). sands and gravels alternate irregularly forming interlayers and lens-shaped bodies. clays are deposited as cm to dm thick interlayers and lens-shaped bodies within the sands. the thickness of these deposits ranges between 50 to 100 m. loess (pleistocene – l) is a clayey-sandy silt of aeolian origin and covers older, neogene deposits (pikija, 1986). the main mineral constituent is quartz (70%), followed by feldspar (16%), rock fragments (10%) and muscovite (4%), with a carbonate content of up to 13%. carbonate and limonite concretions are often observed. around petrinja and cerje, lenticular interlayers of fine-grained gravels are also seen. loess has characteristic vertical fractures forming loess bluffs. the thickness of loess deposits is up to 30 m. holocene alluvial sediments (a, ap) are the most widespread quaternary sediments in the area. alluvial plain sediments are located in the sava river valley on the lekenička poljana sisak hrastelnica line (pikija, 1986). silts predominate over sands and gravels. oxbow lake sediments form characteristic arched and elongated depressions, filled with mud, silt and sand deposited during floods. these deposits are usually up to 5 m thick. holocene swamp deposits (b) are observed in the morphologically lowest parts of the sava and kupa river valleys. they are mostly composed of dark clays and clayey silts rich in organic matter (pikija, 1986) 1 to 4 m thick. diluvial and proluvial sediments (dpr) are predominantly represented by sands and silts, although gravels and larger boulders can also be observed. they formed by surface water runoff g eologia c roatica pollak et al.: the preliminary inventory of coseismic ground failures related to december 2020 – january 2021 petrinja earthquake series 193 and torrential flows from elevated areas, i.e. as a result of the combined seasonal deposition from mountain streams and creeks and ponds formed along margins of larger river valleys (e.g. the sava, una and glina rivers) (pikija, 1986; šikić, 2014b). the thickness of these deposits is variable, locally it exceeds 10 m. 2.2. tectogenesis of the research area the oldest exposed jurassic and cretaceous rock complexes of the banija region are at least partly of ophiolitic origin, emplaced here as a result of obduction that began during the middle jurassic and terminated during middle cretaceous times (schmid et al., 2020) for a regional tectonic aspect. the upper cretaceous volcano-sedimentary complex is locally characterised by pelagic “scaglia-type” limestones and turbidites, interlayered with pillow basalts and associated with a bimodal igneous succession comprising gabbros, doleritic dykes and rhyolites, all well exposed in the neighbouring kozara mts. in northern bosnia and herzegovina. there, this complex is interpreted as originating from a deep basin floored by oceanic lithosphere, that probably represented a remnant of the vardar ocean (ustaszewski et al., 2009), which finally closed during the palaeogene along the sava suture zone (pamić, 2002; ustaszewski et al., 2010; schmid et al., 2020). during the early and middle miocene, the research area was affected by regional-scale extension linked to rift-related subsidence and formation of the pannonian basin system, that in this area resulted in formation of the sava basin and the neighbouring karlovac basin (tomljenović & csontos, 2001; saftić et al., 2003; ustaszewski et al., 2010). after the pontian and during the plio-quaternary the extensional tectonic regime in the pannonian basin was replaced by reginal-scale compression (bada et al., 2007), which led to local inversion of previously active normal faults into faults with reverse sense of slip, often in association with newly formed reverse and strike slip faults (tomljenović and csontos, 2001; ustaszewski et al., 2014), such as those responsible for the zagreb (march 22, 2020) and the petrinja (december 29, 2020) earthquakes, respectively. 2.3. seismicity most of the recorded events of the petrinja earthquake series (december 2020 – january 2021) so far are attributed to the petrinja composite seismogenic source that is known in the european database of seismogenic faults (basili et al., 2013) under the code hrcs027. based on fault characteristics and seismological considerations, the maximum expected magnitude that is presumed for this source is 6.5 in the moment magnitude scale. the strongest destructive mw 6.4 earthquake occurred on the 29th december 2020, 12:19 local time with an epicentre in the village of strašnik, 6 km sw of petrinja at a preliminary estimated hypocentre depth of 10 km. it caused the loss of seven lives and severe damage to buildings and infrastructure in the cities of sisak, petrinja, glina, dvor, kravarsko and the surrounding villages, but also in the remote town of zaprešić, some 60 km nw of the epicentre. the intensity at the epicentre is estimated to be viii-ix° of european macroseismic scale (ems), described as heavily damaging to destructive. before this event there were three foreshocks, the strongest of which with a magnitude 5.2 mw the day before the main shock. currently, the seismic series is still ongoing with already more than 1000 earthquakes above magnitude ml 1.5 recorded in the first couple of days after the mainshock. aftershock seismicity is mostly located on the main seismogenic fault (hrcs027) with some earthquakes located on adjacent faults parallel to the main one. so far, recorded seismici ty indicates that a 20 km long section of the fault ruptured with aftershock depths ranging from 5 to 15 km. results from this up to january 13th 2021, suggest that in sisak-moslavina county, 33 590 buildings were reported as damaged and 15 626 were inspected by civil engineers and deemed as follows: – 2292 (15%) are classified as unusable; – 1655 (11%) are classified as temporarily unusable – detailed inspection needed; – 1986 (13%) are classified as temporarily unusable – emergency interventions needed; – 5830 (36%) are classified as usable with recommendations for action – 410 (3%) are classified as usable with no damage; – 3453 (22%) are classified as usable with no limitations. among these, more than 3 000 building inspection reports encompass the problems related to the soil surrounding the building, and the necessity for detailed geotechnical and geological inspection. according to the last census (2011) the population of sisakmoslavina county was 172 439, but in the most damaged areas (petrinja, sisak, glina, dvor and several smaller villages) the population was less than 90 000. even if we ignore the emigration of the population in recent years, the number of damaged buildings in comparison with the population is substantial. the direct damage of intensive ground-shaking on the buildings and infrastructure are evaluated by several services and numerous experts, mainly civil engineers. besides, the same earthquake series also caused a variety of ground failures over a wider area, which represent additional, direct and indirect threats to the local community and their property, which have so far not been considered by those experts and civil protection services. 3. the preliminary inventory the ground failure inventories related to particular seismic events or series are prepared to improve the ability to assess earthquaketriggered ground failure hazards. such inventories enable the use of analysis of effects of a single triggering event on particular ground failures or effects. the inventories are most commonly related to particular countries or regions. therefore, united states geological survey (usgs) created an openly accessible, centralized earthquake-triggered ground failure repository in the form of a sciencebase community to provide open access to data with the goal of accelerating research progress (schmitt, 2017). the digital inventories in that community are created by both usgs and non-usgs authors. italy has a very extensive database on earthquake-induced ground effects, which has been upgraded over time. the database contains data regarding landslides, liquefaction, ground cracks, surface faulting and ground changes triggered by earthquakes of mercalli epicentral intensity 8 or greater, that occurred in the last millennium (martino et al., 2014). the same database was upgraded with new architecture in order to increase its usefulness for both public institutions and individual users (caprari et al., 2018). as already mentioned above, historical records of ground failures in croatia are very scarce. two catastrophic earthquakes with an estimated x° mcs scale are chronicled. for example, there is a legend about a possible earthquake that struck the island of pag in the year 361 ad when, according to oral tradition, the g eo lo gi a c ro at ic a geologia croatica 74/2194 of the phenomena, e.g. a subsidence doline or landslide. in other cases, single records in the database rather present locations or zones where multiple appearances of some process of phenomena are documented (i.e. sand boils, lateral spreading and different type of ruptures). the inventory contains basic information about ground failures: no. (number of record), id (label for the observation point), ground failure/effect type, coordinates (coordinate reference systemhtrs96 croatia tm), data provider, processing date (field identification date, date of registration) and reliability (table 2). the reliability of the data in the inventory is defined on the level of expertise by the reporter and the precision of spatial positioning. therefore, the processes reported or verified by certified experts with exact coordinates are considered as highly confident. unverified reports by non-professionals with approximate locations are considered to have low confidence. all cases in between are classified as medium confident. city of cissa collapsed into the sea. in 1667, the catastrophic dubrovnik earthquake caused thousands of deaths (the estimations on number of victims differ), totally demolished almost the whole city, triggered rockfalls of huge blocks from srđ mountain that caused great devastation and initiated a tsunami that damaged ships in the harbour (herak et al., 2017a). more exact historical records about seismogenic ground effects are mainly related to the earthquake near zagreb in 1880. that earthquake with a magnitude of 6.3 initiated: liquefaction at several locations in the zone of sava alluvium (stupnik, jarun, resnik, ivanja reka, drenje and trstenik); raised the groundwater table (krapinske toplice, novo čiče, lukač); created suffosion processes forming dolines (stubičke toplice); ground ruptures (kašina) and triggered rockfalls (severin na kupi) (torbar, 1882). in recent history, the earthquake near zagreb ml 5.5 2020 march 22nd 2020 caused the loss of one life and considerable material damage (šavor novak et al., 2020), but ground failures were not reported. however, as reported by bačić et al. (2020), geological and geotechnical phenomena within the underlying soil yielded significant damage to some of the buildings constructed in the vicinity of identified faults and landslides. the much stronger petrinja mw 6.4 2020 earthquake initiated various processes/effects, which can generally be divided into two main groups: ground failures and other ground effects (table 1). therefore, the database presented here is adjusted for up to date knowledge about historical and recent earthquake-triggered ground failures in croatia. in this paper it presents data collected from 30th of december 2020 until 15th of january 2021 related to the petrinja 2020-2021 earthquake series only, but as has already been stated, the database will be continuously updated online, at the hgi web map service at www.hgi-cgs.hr. it is important to point out that a single record in the database is for some processes/phenomena related to a single occurrence table 1. the earthquake-triggered ground effects and subdivisions included in the inventory. ground effects processes phenomena/feature no. of occurrences / locations ground failures subsidence dolines dropout doline 35 suffosion doline 4 liquefaction sand boil 85 lateral spreading 8 subsidence 6 landslides slide 36 rockfall 4 other ground effects geological soil rupture 20 clouding of springwater 1 infrastructural road rupture 54 table 2. the preliminary inventory of ground failures and other ground effects after the petrinja 2020 earthquake. no id ground failure type phenomena/process x y data provider processing date data confidence level subsidence 1 ik1 dropout doline 494638 5015706 hgi 13.01.2021. high 2 ik10 dropout doline 494230 5016289 hgi 13.01.2021. high 3 ik11 dropout doline 494219 5016193 hgi 13.01.2021. high 4 ik12 dropout doline 494236 5016257 hgi 13.01.2021. high 5 ik13 dropout doline 494010 5016789 hgi 13.01.2021. high 6 ik14 dropout doline 494002 5016794 hgi 13.01.2021. high 7 ik17 dropout doline 493781 5017077 hgi 13.01.2021. high 8 ik18 dropout doline 493677 5017093 hgi 13.01.2021. high 9 ik19 dropout doline 493597 5017146 hgi 13.01.2021. high 10 ik2 dropout doline 494663 5015641 hgi 13.01.2021. high 11 ik20 dropout doline 493589 5017180 hgi 13.01.2021. high 12 ik21 dropout doline 493598 5017171 hgi 13.01.2021. high 13 ik22 dropout doline 493425 5017321 hgi 13.01.2021. high 14 ik23 dropout doline 493431 5017341 hgi 13.01.2021. high 15 ik25 dropout doline 493449 5017139 hgi 13.01.2021. high 16 ik26 dropout doline 493459 5017136 hgi 13.01.2021. high 17 ik27 dropout doline 493499 5017123 hgi 13.01.2021. high 18 ik28 dropout doline 493556 5017112 hgi 13.01.2021. high 19 ik29 dropout doline 493564 5017102 hgi 13.01.2021. high 20 ik30 dropout doline 494514 5015761 hgi 13.01.2021. high 21 ik31 dropout doline 494496 5015874 hgi 13.01.2021. high g eologia c roatica pollak et al.: the preliminary inventory of coseismic ground failures related to december 2020 – january 2021 petrinja earthquake series 195 no id ground failure type phenomena/process x y data provider processing date data confidence level 22 ik32 dropout doline 494462 5015878 hgi 13.01.2021. high 23 ik33 dropout doline 494386 5015780 hgi 13.01.2021. high 24 ik34 dropout doline 494321 5015781 hgi 13.01.2021. high 25 ik35 dropout doline 493266 5016975 hgi 13.01.2021. high 26 ik4 dropout doline 494186 5015950 hgi 13.01.2021. high 27 ik5 dropout doline 494138 5015846 hgi 13.01.2021. high 28 ik6 dropout doline 494100 5015895 hgi 13.01.2021. high 29 ik7 dropout doline 494123 5016224 hgi 13.01.2021. high 30 ik8 dropout doline 494120 5016287 hgi 13.01.2021. high 31 ik9 dropout doline 494219 5016329 hgi 13.01.2021. high 32 ik-37 dropout doline 493938 5016123 hgi 20.01.2021. high 33 ik-39 dropout doline 493885 5016101 hgi 20.01.2021. high 34 ik-40 dropout doline 494125 5016227 hgi 20.01.2021. high 35 ik-41 dropout doline 492843 5017598 hgi 20.01.2021. high 36 ik15 suffosion doline 493911 5016862 hgi 13.01.2021. high 37 ik16 suffosion doline 493861 5017003 hgi 13.01.2021. high 38 ik24 suffosion doline 493613 5016984 hgi 13.01.2021. high 39 ik3 suffosion doline 494656 5015991 hgi 13.01.2021. high liquefaction 40 p-ndtv-12b sand boil 481448 5032639 hgi 05.01.2021. high 41 p-ndtv-13a sand boil 481504 5032582 hgi 05.01.2021. high 42 pe-ndtv-02 sand boil 481883 5032780 hgi 05.01.2021. high 43 pe-ndtv-03 sand boil 481838 5032783 hgi 05.01.2021. high 44 pe-ndtv-04 sand boil 481834 5032784 hgi 05.01.2021. high 45 pe-ndtv-05 sand boil 481814 5032793 hgi 05.01.2021. high 46 pe-ndtv-06 sand boil 481827 5032750 hgi 05.01.2021. high 47 pe-ndtv-07 sand boil 481800 5032746 hgi 05.01.2021. high 48 pe-ndtv-08 sand boil 481736 5032716 hgi 05.01.2021. high 49 pe-ndtv-09 sand boil 481653 5032627 hgi 05.01.2021. high 50 pe-ndtv-10 sand boil 481629 5032610 hgi 05.01.2021. high 51 pe-ndtv-11 sand boil 481436 5032602 hgi 05.01.2021. high 52 pe-ndtv-15 sand boil 481837 5032832 hgi 05.01.2021. high 53 pe-ndtv-16 sand boil 481783 5032842 hgi 05.01.2021. high 54 si-01 sand boil 491454 5037182 hgi 05.01.2021. high 55 si-04 sand boil 491773 5036963 hgi 05.01.2021. high 56 si-05 sand boil 491670 5037051 hgi 05.01.2021. high 57 v-01 sand boil 481401 5033976 hgi 09.01.2021. high 58 rmt-11 sand boil 476846 5040083 hgi 04.01.2021. high 59 rmt-12 sand boil 476693 5040607 hgi 04.01.2021. high 60 rmt-17 sand boil 470568 5030270 hgi 04.01.2021. high 61 rmt-19 sand boil 472346 5038019 hgi 05.01.2021. high 62 rmt-20 sand boil 468309 5036590 hgi 05.01.2021. high 63 rmt-21 sand boil 468320 5036356 hgi 05.01.2021. high 64 rmt-22 sand boil 468391 5036401 hgi 05.01.2021. high 65 rmt-23 sand boil 468423 5036435 hgi 05.01.2021. high 66 rmt-28a sand boil 469995 5025866 hgi 05.01.2021. high 67 rmt-34b sand boil 477383 5041120 hgi 07.01.2021. high 68 rmt-35a sand boil 477582 5040954 hgi 07.01.2021. high 69 rmt-36 sand boil 477608 5040971 hgi 07.01.2021. high 70 rmt-37 sand boil 477681 5040990 hgi 07.01.2021. high 71 rmt-37a sand boil 477696 5041003 hgi 07.01.2021. high 72 rmt-37c sand boil 477722 5041036 hgi 07.01.2021. high 73 rmt-49 sand boil 470030 5033099 hgi 07.01.2021. medium 74 rmt-50 sand boil 465677 5046800 hgi 07.01.2021. high 75 mv-1 sand boil 481233 5034723 hgi 30.12.2020. high 76 mv-26 sand boil 481241 5034479 hgi 04.01.2021. high 77 mv-28 sand boil 485589 5036755 hgi 04.01.2021. high 78 mv-29 sand boil 487149 5035782 hgi 04.01.2021. high 79 mv-31 sand boil 481356 5033058 hgi 05.01.2021. high table 2. continued g eo lo gi a c ro at ic a geologia croatica 74/2196 no id ground failure type phenomena/process x y data provider processing date data confidence level 80 mv-32 sand boil 481392 5032955 hgi 05.01.2021. high 81 mv-34 sand boil 493935 5042867 hgi 05.01.2021. high 82 mv-35 sand boil 493257 5042439 hgi 05.01.2021. high 83 mv-36 sand boil 492637 5042213 hgi 05.01.2021. high 84 mv-37 sand boil 492202 5042157 hgi 05.01.2021. high 85 np-13 sand boil 487317 5035347 hgi 04.01.2021. high 86 np-15 sand boil 479994 5033591 hgi 05.01.2021. high 87 np-22 sand boil 492859 5041123 hgi 07.01.2021. high 88 np-23 sand boil 492724 5040426 hgi 07.01.2021. high 89 np-26 sand boil 491978 5036711 hgi 07.01.2021. high 90 np-30 sand boil 471583 5028895 hgi 07.01.2021. high 91 np-31 sand boil 480133 5034511 hgi 13.01.2021. high 92 jb-1 sand boil 468823 5025602 hgi 07.01.2021. high 93 jb-2 sand boil 468416 5024971 hgi 07.01.2021. high 94 jb-6 sand boil 468364 5022176 hgi 07.01.2021. high 95 jb-7 sand boil 468298 5022237 hgi 07.01.2021. high 96 šp-7 sand boil 485645 5035151 hgi 04.01.2021. high 97 šp-8 sand boil 491626 5042295 hgi 05.01.2021. high 98 šp-9 sand boil 491659 5042255 hgi 05.01.2021. high 99 šp-17 sand boil 485075 5035494 hgi 05.01.2021. high 100 tss-2 sand boil 481298 5034640 rgnf 05.01.2021. high 101 tss-3 sand boil 493197 5042455 rgnf 05.01.2021. high 102 geot-4 sand boil 481485 5032868 geot 12.01.2021. medium 103 geot-12 sand boil 481786 5035259 geot 12.01.2021. medium 104 geot-14 sand boil 490382 5039444 geot 12.01.2021. medium 105 geot-28 sand boil 481755 5033624 geot 12.01.2021. medium 106 geot-29 sand boil 490464 5039161 geot 12.01.2021. medium 107 geot-30 sand boil 467978 5022537 geot 12.01.2021. medium 108 geot-31 sand boil 481632 5032863 geot 12.01.2021. medium 109 geot-32 sand boil 481389 5032981 geot 12.01.2021. medium 110 nvi-05 sand boil 481477 5032892 hgi 19.01.2021. high 111 nvi-05a sand boil 481463 5032854 hgi 19.01.2021. high 112 nvi-06 sand boil 481505 5032792 hgi 19.01.2021. high 113 nvi-07 sand boil 481507 5032791 hgi 19.01.2021. high 114 nvi-10 sand boil 481372 5032989 hgi 19.01.2021. high 115 gti-01 sand boil 481114 5034850 gti 20.01.2021. high 116 gti-02a sand boil 481882 5032867 gti 20.01.2021. high 117 gti-02b sand boil 481878 5032825 gti 20.01.2021. high 118 vi-03 sand boil 476421 5040754 hgi 20.01.2021. high 119 vi-09 sand boil 475259 5037960 hgi 20.01.2021. high 120 vi-10 sand boil 475561 5038219 hgi 20.01.2021. high 121 vi-11 sand boil 475469 5038256 hgi 20.01.2021. high 122 vi-12 sand boil 475035 5037857 hgi 20.01.2021. high 123 vi-13 sand boil 475055 5037862 hgi 20.01.2021. high 124 vi-15 sand boil 473643 5038416 hgi 20.01.2021. high 131 si-02 lateral spreading 491660 5036857 hgi 05.01.2021. high 132 rmt-35 lateral spreading 477562 5040939 hgi 07.01.2021. high 133 np-12 lateral spreading 487151 5035769 hgi 04.01.2021. high 134 np-21 lateral spreading 492335 5042079 hgi 05.01.2021. high 135 gti-06 lateral spreading 481089 5034247 gti 20.01.2021. high 136 vi-06 lateral spreading 475295 5037837 hgi 20.01.2021. high 137 vi-07 lateral spreading 475218 5037965 hgi 20.01.2021. high 138 vi-08 lateral spreading 475348 5037831 hgi 20.01.2021. high 125 p-ndtv-05a subsidence 481812 5032798 hgi 05.01.2021. high 126 p-ndtv-06a subsidence 481825 5032746 hgi 05.01.2021. high 127 p-ndtv-11a subsidence 481438 5032609 hgi 05.01.2021. high 128 p-ndtv-12a subsidence 481471 5032626 hgi 05.01.2021. high 129 si-03 subsidence 491818 5036749 hgi 05.01.2021. high 130 mv-37a subsidence 492202 5042157 hgi 05.01.2021. high table 2. continued g eologia c roatica pollak et al.: the preliminary inventory of coseismic ground failures related to december 2020 – january 2021 petrinja earthquake series 197 no id ground failure type phenomena/process x y data provider processing date data confidence level landslides 139 pe-ndtv-01 slide 482878 5031095 hgi 05.01.2021. high 140 pe-ndtv-12 slide 481474 5032619 hgi 05.01.2021. high 141 pe-ndtv-13 slide 481496 5032594 hgi 05.01.2021. high 142 pe-ndtv-14 slide 481511 5032676 hgi 05.01.2021. high 143 np-16 slide 482924 5025926 hgi 05.01.2021. high 144 šp-1 slide 480887 5030303 hgi 04.01.2021. high 145 šp-3 slide 479527 5029032 hgi 04.01.2021. high 146 tss-9 slide 464747 5024336 rgnf 05.01.2021. high 147 geot-1 slide 464873 5027706 geot 12.01.2021. medium 148 geot-2 slide 464471 5043053 geot 12.01.2021. medium 149 geot-3 slide 475922 5031004 geot 12.01.2021. medium 150 geot-6 slide 500430 5010142 geot 12.01.2021. medium 151 geot-7 slide 468013 5022625 geot 12.01.2021. medium 152 geot-8 slide 485421 5022788 geot 12.01.2021. medium 153 geot-10 slide 482610 5023631 geot 12.01.2021. low 154 geot-11 slide 467962 5022471 geot 12.01.2021. low 155 geot-13 slide 480890 5032753 geot 12.01.2021. medium 156 geot-17 slide 476987 5032775 geot 12.01.2021. low 157 geot-18 slide 483558 5028393 geot 12.01.2021. medium 158 geot-21 slide 480961 5034683 geot 12.01.2021. medium 159 geot-22 slide 484231 5027591 geot 12.01.2021. medium 160 geot-25 slide 482973 5026073 geot 12.01.2021. medium 161 geot-27 slide 486499 5017777 geot 12.01.2021. medium 162 ik-klz1 slide 490843 5018292 hgi 13.01.2021. medium 163 nvi-01 slide 506036 5020302 hgi 19.01.2021. high 164 nvi-02 slide 495761 5028047 hgi 19.01.2021. high 165 nvi-08 slide 481404 5032745 hgi 19.01.2021. high 166 gti-03a slide 470225 5026717 gti 20.01.2021. high 167 gti-03b slide 470238 5026682 gti 20.01.2021. high 168 gti-03c slide 470121 5026487 gti 20.01.2021. high 169 vi-01 slide 477421 5040997 hgi 20.01.2021. high 170 vi-02 slide 477694 5040845 hgi 20.01.2021. high 171 vi-04 slide 473997 5038388 hgi 20.01.2021. high 172 vi-05 slide 475133 5037725 hgi 20.01.2021. high 173 vi-17 slide 472210 5038568 hgi 20.01.2021. high 174 vi-18 slide 472124 5038608 hgi 20.01.2021. high 175 hr-dn-02 rockfall 482859 5028347 hgi 05.01.2021. high 176 rmt-24 rockfall 462393 5031336 hgi 05.01.2021. high 177 šp-16 rockfall 483128 5028418 hgi 04.01.2021. high 178 ik-odr rockfall 480287 5027202 hgi 14.01.2021. high geological 179 rmt-5 soil rupture 475149 5033810 hgi 04.01.2021. high 180 rmt-7 soil rupture 474978 5032745 hgi 04.01.2021. high 181 rmt-8 soil rupture 474935 5032603 hgi 04.01.2021. high 182 rmt-10 soil rupture 474902 5032794 hgi 04.01.2021. high 183 rmt-14 soil rupture 474043 5038129 hgi 04.01.2021. high 184 rmt-27 soil rupture 471742 5027712 hgi 05.01.2021. high 185 rmt-34a soil rupture 477383 5041120 hgi 07.01.2021. high 186 rmt-37b soil rupture 477704 5041022 hgi 07.01.2021. high 187 rmt-38 soil rupture 477764 5041061 hgi 07.01.2021. high 188 mv-11 soil rupture 478416 5031477 hgi 30.12.2020. high 189 mv-20 soil rupture 478261 5031617 hgi 04.01.2021. high 190 np-25 soil rupture 491818 5036749 hgi 07.01.2021. high 191 tss-4 soil rupture 492419 5042102 rgnf 05.01.2021. high 192 tss-6 soil rupture 465989 5044352 rgnf 05.01.2021. high 193 tss-8 soil rupture 465701 5046760 rgnf 05.01.2021. high 194 geot-9 soil rupture 475062 5032742 geot 12.01.2021. medium 195 geot-16 soil rupture 479668 5039767 geot 12.01.2021. medium table 2. continued g eo lo gi a c ro at ic a geologia croatica 74/2198 no id ground failure type phenomena/process x y data provider processing date data confidence level 196 geot-19 soil rupture 481759 5035271 geot 12.01.2021. medium 197 vi-14 soil rupture 473739 5038352 hgi 20.01.2021. high 198 vi-16 soil rupture 472650 5038286 hgi 20.01.2021. high 253 hr-dn-01 clouding of springwater 482977 5028375 hgi 05.01.2021. high infrastructural 199 si-06 road rupture 490317 5039630 hgi 05.01.2021. high 200 rmt-3 road rupture 477178 5033155 hgi 04.01.2021. high 201 rmt-13 road rupture 476121 5036980 hgi 04.01.2021. high 202 rmt-15 road rupture 479011 5032783 hgi 04.01.2021. high 203 rmt-16 road rupture 470485 5030089 hgi 04.01.2021. high 204 rmt-18 road rupture 473752 5036859 hgi 05.01.2021. high 205 rmt-25 road rupture 471772 5027624 hgi 05.01.2021. high 206 rmt-26 road rupture 471744 5027688 hgi 05.01.2021. high 207 rmt-28 road rupture 469995 5025866 hgi 05.01.2021. high 208 rmt-31 road rupture 479609 5041418 hgi 07.01.2021. high 209 rmt-32 road rupture 479117 5041335 hgi 07.01.2021. high 210 rmt-33 road rupture 477440 5041161 hgi 07.01.2021. high 211 rmt-34 road rupture 477383 5041120 hgi 07.01.2021. high 212 rmt-40 road rupture 470620 5039412 hgi 07.01.2021. high 213 rmt-41 road rupture 469622 5038340 hgi 07.01.2021. high 214 rmt-42 road rupture 469564 5038235 hgi 07.01.2021. high 215 rmt-43 road rupture 469564 5038202 hgi 07.01.2021. high 216 rmt-44 road rupture 469530 5038129 hgi 07.01.2021. high 217 rmt-45 road rupture 469402 5038127 hgi 07.01.2021. high 218 rmt-46 road rupture 469364 5038134 hgi 07.01.2021. high 219 rmt-47 road rupture 469213 5038807 hgi 07.01.2021. medium 220 rmt-48 road rupture 468228 5037625 hgi 07.01.2021. high 221 rmt-51 road rupture 464773 5042397 hgi 07.01.2021. high 222 rmt-52 road rupture 465548 5043364 hgi 07.01.2021. high 223 rmt-53 road rupture 466068 5044321 hgi 07.01.2021. high 224 mv-2 road rupture 481193 5034203 hgi 30.12.2020. high 225 mv-3 road rupture 478036 5032639 hgi 30.12.2020. high 226 mv-8 road rupture 479017 5032643 hgi 30.12.2020. medium 227 mv-9 road rupture 478292 5031591 hgi 30.12.2020. high 228 mv-10 road rupture 478342 5031565 hgi 30.12.2020. high 229 mv-12 road rupture 478544 5031382 hgi 30.12.2020. high 230 mv-13 road rupture 478842 5031213 hgi 30.12.2020. high 231 mv-14 road rupture 479186 5031158 hgi 30.12.2020. high 232 mv-15 road rupture 479385 5031222 hgi 30.12.2020. high 233 mv-16 road rupture 479975 5031360 hgi 30.12.2020. high 234 mv-17 road rupture 480701 5030415 hgi 30.12.2020. high 235 mv-18 road rupture 480379 5030066 hgi 30.12.2020. high 236 mv-19 road rupture 480192 5029947 hgi 30.12.2020. medium 237 mv-21 road rupture 478159 5031553 hgi 04.01.2021. high 238 mv-22 road rupture 478950 5032157 hgi 04.01.2021. high 239 mv-24 road rupture 481153 5033888 hgi 04.01.2021. high 240 mv-25 road rupture 481370 5034062 hgi 04.01.2021. high 241 mv-27 road rupture 481360 5034587 hgi 04.01.2021. high 242 mv-30 road rupture 481419 5033078 hgi 04.01.2021. high 243 mv-33 road rupture 483311 5026330 hgi 05.01.2021. high 244 jb-3 road rupture 470110 5025591 hgi 07.01.2021. high 245 šp-5 road rupture 483356 5026406 hgi 04.01.2021. high 246 šp-10 road rupture 485695 5035094 hgi 05.01.2021. high 247 šp-11 road rupture 480333 5027108 hgi 04.01.2021. high 248 šp-12 road rupture 479690 5026544 hgi 04.01.2021. high 249 šp-14 road rupture 480866 5030242 hgi 04.01.2021. high 250 šp-18 road rupture 487411 5025085 hgi 05.01.2021. high 251 tss-7 road rupture 478145 5031572 rgnf 05.01.2021. high 252 gti-07 road rupture 485160 5034297 gti 20.01.2021. high table 2. continued g eologia c roatica pollak et al.: the preliminary inventory of coseismic ground failures related to december 2020 – january 2021 petrinja earthquake series 199 3.1. ground failures ground failures are largely related to subsidence, liquefaction, and landsliding processes. 3.1.1. subsidence dolines subsidence is the sudden sinking or gradual downward settling of the earth’s surface with little or no horizontal motion (bates & jackson, 1980). subsidence may be caused by different natural geological processes, but here subsidence caused by suffosion or liquefaction is of primary concern. the ground shaking caused by the petrinja earthquake series triggered rapid development of subsidence dolines in the wider mečenčani area, about 20 km se of the mainshock epicentre. actually, in this area dolines were registered throughout history and obviously, strong earthquake accelerated the process significantly. theoretically, two types of subsidence dolines are recognised: suffosion and dropout dolines (kranjc, 2013; figure 3). both types are developed by suffosion, a filtration process in which fine particles are washed away from cover sediments overlying carbonate bedrock or other soluble rocks, into their karstified fissures or caverns. in the area of mečenčani, mainly dropout dolines are developed. in this type of doline cover sediments are evacuated downwards through solution pipes in the bedrock creating a void at the bedrock-sediment contact that enlarges by upwards propagation through the clastic coverbeds (williams, 2004; figure 3). at the time of writing this manuscript, 35 records were entered in the inventory (figure 4, table 1), but up to february 15th 2021, more than ninety (90) subsidence dolines were registered in the area between borojevići and mečenčani in the donji kukuruzari municipality. the great majority of these are classified as dropout dolines formed by the sudden (or over a few hours) collapse of cover sediments into the underground voids, forming steep-sided cylindrical depressions. the majority of the dolines are between 1 and 10 m in diameter, but the largest one is more figure 3. the sketches of: a) suffosion doline and b) dropout doline. reproduced from waltham & fookes (2003). figure 4. dropout dolines in mečenčani village: a) endangering adjacent houses (observation point ik31), b) the biggest doline, more than 20m in diameter and about 12 m deep (observation point ik4). a) b) a) b) g eo lo gi a c ro at ic a geologia croatica 74/2200 than 20 m in diameter, and is still enlarging. therefore, their final dimensions are not yet known. new dolines are still forming, almost twenty days after the main earthquake event. other than dropout dolines, the suffosion dolines are also registered (at the mečenčani school backyard and in fields near the village), indicating the gradual subsidence of superficial coverbeds which form a funnel-shaped depression at the surface (table 1). as opposed to dropout dolines, in this case the process advances from the surface, usually in noncohesive sediment, as the finer fraction tends to move into the cavity underneath, whereas the coarser fraction remains closer to the surface (kranjc, 2013). 3.1.2. liquefaction liquefaction is a phenomenon wherein a mass of soil loses a large percentage of its shear resistance and flows in a manner resembling a liquid. the basic cause responsible for the liquefaction of saturated sands is the build-up of excess pore water pressure due to either cyclic or shock loading of the sand (e.g. during an earthquake). if drainage cannot take place, then the tendency to compress the volume of the grains causes an increase in pore water pressure. in loose sands, pore water pressure can build up to the point where it is the same as the overburden pressure, causing complete loss of strength which initiates liquefaction. however, norris et al. (1998) pointed out that a loose sand does not always lose all strength during liquefaction. loose sands at low confining pressure, and medium and dense sands undergo only limited deformation due to dilation once initial liquefaction has occurred. such a response is referred to as ranging from limited liquefaction (in the case of loose and medium dense sands at low confining pressure) to dilative behaviour (in dense sands) (bell, 2007). liquefaction is more likely to occur in sandy or non-plastic silty soils, but may in rare cases occur in gravels and clays. the increase of the portion of finer particles in the sand somewhat increases the resistance to liquefaction. also, liquefaction is most commonly reported in the upper 12 to 15 m of the soil profile. the liquefaction of subsurface layers in the research area is recognised by sand boiling phenomena. a sand boil is sand and water that erupts out onto the ground surface during an earthquake as a result of liquefaction at shallow depths (usgs earthquake glossary, 2021). the research area exhibited many locations with such features, eighty-five are in the database at present (table 2). most of the sand boils are aligned in a row along a line ar fracture exposed at the surface (figure 5). locations of sand boil phenomena are found in several areas adjacent to the rivers sava, kupa and glina and are clear indications of liquefied zones. coseismic liquefaction in the research area also initiated lateral spreading, subsidence and river bank failures. the aforementioned processes are in some cases interrelated. lateral spreading is a type of movement that refers to movement of rock blocks or very coherent soil masses that rest on soft, deformable material (gonzález de vallejo & ferrer, 2011). these movements are due to the loss of strength of the underlying material, which either flows or is deformed under the weight of the rigid blocks. here, the lateral spreading is the result of liquefaction of the saturated and loose sandy layers, and occurred on the flood embankments of the river sava but also on the natural kupa and petrinjčica river banks (figure 6). horizontal displacements in most of the cases are from a few centimetres to several decimetres. subsidence caused by liquefaction is related to larger liquified zones and is registered at six sites. it is recognised or suspected in populated areas of petrinja (vinogradska and milana makanca street zones), sisak and at the edges of smaller settlements stari brod, letovanić, brest, drenčina and palanjek. according to our knowledge, the vertical displacements in densely populated areas are up to 10 centimetres. larger vertical displacements of several decimetres are noted in the immediate vicinity of the kupa and sava rivers (figure 7). 3.1.1. landslides landslide is a general term covering wide variety of mass-movement landforms and processes (including slides and rockfalls) involving the downslope transport of soil and rock material, under gravitational influence. landslides can be triggered by earthquakes. according to keefer (1984) an earthquake with a richter magnitude of 4 would probably not generate slides, but rockfalls and rock slides could be triggered by the weaker seismic tremors. figure 5. the sand boiling features along linear fractures: a) in letovanić (aerial photo); b) in sisak (observation point si-04). a) b) g eologia c roatica pollak et al.: the preliminary inventory of coseismic ground failures related to december 2020 – january 2021 petrinja earthquake series 201 slide is a landslide characterized by a shearing and rotary movement of a generally independent mass of rock or soil along the curved slip surface (concave upward) and about an axis parallel to the slope from which it descends (bates & jackson, 1980). rockfall is another type of landslide characterised by precipitous movement, free falling, bouncing or rolling, of a newly detached segment of bedrock of any size from a cliff or other very steep slope (bates & jackson, 1980; dorren, 2003). along the detachment surface, little or no shear displacement takes place (varnes, 1978). thirtysix slides and four rockfalls have been registered so far, after the petrinja 2020 earthquake. most of the registered slides or rockfalls are older landslides reactivated by ground motion. their nature and horizontal displacements vary greatly (figu re 8). it has been noted that even minor or not visible displacements, together with ground shaking could generate greater material damage on the structures located at the edge or inside the colluvium material. some of the areas affected by the reactivation of landslides (mainly shallow ones), caused by the earthquake, are hađer, stari farkašić, petrinja and sunja. also, as already mentioned, in some cases slope failures are the consequence of liquefaction and lateral spreading. that is particularly the case in the zones where lateral support of the top layer is absent, dominantly along the river banks of the kupa and petrinjčica rivers (figure 6). rockfalls have also been registered. most of them are located below known rockfall source areas or steep slopes. since rockfalls are very rapid to extremely rapid events, ground motions of this earthquake immediately triggered block motions causing rolling and bouncing of the blocks of various sizes into the foot of the slope (figure 8b). 3.2. other ground effects other registered coseismic ground effects will be shortly presented, because these effects still remain to be evaluated and interpreted in the near future. so far, the observed ground effects are preliminary differentiated according to the medium in which figure 6. lateral spreading and associated processes: a) failure of the flood embankment in sisak (observation point si-03); b) road failure in letovanić (observation point rmt-35). figure 7. subsidence and lateral spreading of the embankments near the sava river: a) in sisak (observation point si-03); b) in palanjek (observation point np-21). a) b) a) b) g eo lo gi a c ro at ic a geologia croatica 74/2202 they are registered. earthquake-induced ground effects in natural materials are classified as geological, while all other effects on man-made structures are considered as infrastructural (table 1). a number of soil ruptures are observed in various lithologies (figure 2). in general, two types of soil ruptures can be differentiated. the first group comprises ruptures closely related to the main seismogenic fault zone that triggered the major earthquake. the second group comprises soil ruptures that are related to liquified zones and surface subsidence. fracture displacements are usually up to a few centimetres, rarely several decimetres (figure 9). at a single location in hrastovica, the displacement or clouding of springwater is registered. here, before the main earthquake, the groundwater catchment collected all waters above the family house, but after intensive ground shaking, the groundwater emergence was scattered in a wider zone causing groundwater eruption inside and around the family house (figure 10a). numerous road ruptures are also registered (figure 10b). the great majority of these fractures are in the wider zone of the activated seismogenic fault (figure 2). other road ruptures follow minor, local faults, or are related to liquefaction-induced subsidence. figure 8. coseismic landslide activation: a) slide in forest road embankment (near strašnik, observation point šp-3); b) rockfall near pecki that blocked the local road (observation point ik-odr). figure 9. soil rupture: a) near letovanić (observation point rmt-38); b) near župić village (observation point mv-11). a) b) a) b) g eologia c roatica pollak et al.: the preliminary inventory of coseismic ground failures related to december 2020 – january 2021 petrinja earthquake series 203 4. discussion and conclusions as seen from the geological map, the locations of noted coseismic ground failures are strongly related to the geological setting and composition (figure 2). therefore, this chapter provides preliminary comments on the relationship between the geological setting and ground failures occurrences in the research area. in addition, details are presented about existing geological and other relevant data, together with recommendations for further explorations. the spatial distribution of various types of coseismic ground failures/effects in the petrinja earthquake seismic series is shown in figure 2. a similar up to date map view presentation of the collected data, will be available in the form of wms at the croatian geological survey web portal (www.hgi-cgs.hr). despite the fact that data collection for this publication was limited to only two weeks after the major december, 29th 2020 petrinja earthquake, the spatial distribution of the recorded coseismic ground failures and their generating processes already indicate endangered areas. it is possible that further data collection will discover additional locations or areas affected by different post-seismic effects, but here, the comments and conclusions are related to the available information. 4.1. subsidence dolines area the subsidence dolines are exclusively found in the area around the villages of mečenčani and borojevići. this area was surveyed in detail during the hydrogeological investigations for pašino vrelo (šimunović & hećimović, 1998; mraz, 2005; mraz et al., 2007; larva et al., 2010). the terrain is characterised by alluvial and proluvial sediments (al-q2) which overlie miocene rocks (figure 11). freshly exposed steep banks of newly formed dolines facilitate understanding of the nature of alluvial sediments which are soil mixtures of various fractions from clay to gravel. the thickness of these deposits varies from several to ~15 metres in the vicinity of the river sunja. older miocene deposits (m3) are represented by clayey sands and clays. they are overlain by m4 deposits, beginning with conglomerates or breccias followed by lithothamnium limestones. according to geophysical investigations, those limestones are more than 100 m thick in some parts (krsnik, 2005). the lithothamnium limestones represent the main aquifer for pašino vrelo. the upper weathering zone in the limestone is from 10 to 25 m thick, with the frequent appearance of wide-open joints, smaller cavities and caverns (mraz, 2005). groundwater level in this area is very shallow, from 1.2 to 2.0 m. all of the factors are favourable for a good yield of the pašino vrelo which is used for the public water supply. the pašino vrelo is a natural spring, from an old dropout doline, with a short stream that flow toward the sunja river. there are several older dolines in the area, and some of them are periodic rather than permanent springs. it is important to emphasize that groundwater extraction at the pašino vrelo does not significantly influence the total groundwater flow in the area, and the well influence is limited to several tens of metres around it. the closest buildings in villages figure 10. a) clouding of springwater in hrastovica (observation point hr-dn-01); b) road ruptures near pokupsko vratečko (observation point rmt-43). a) b) g eo lo gi a c ro at ic a geologia croatica 74/2204 are some 200m from the spring. since the aquifer is very karstified, the main task in forthcoming future research will be recognizing the main preferential flow paths typical for karst aquifers. groundwater flow is one of the main causes for the development of dropout dolines and they occur mainly above these zones. this process happens regularly in this area, but over long periods of time. the petrinja earthquake series significantly accelerated the collapse of several caverns and initiated the rapid development of new dolines, which represents a serious threat to the houses in this area. since some of the newly formed dolines are developing very closely to family houses and even below them, further detailed research is urgent. firstly, remote sensing (with uavs – unmanned aerial vehicles) of the wider mečenčani and borojevići area in order to determine the exact positions, sizes, and spatial distribution of the dolines was requested. analysis of a detailed digital terrain model obtained by uav data acquisition and the possible detection of newly formed surface depressions can govern the positioning of geophysical profiling and core drilling in order to define the depth of soil cover on top of the limestones, detect existing underground cavities and define their size, interrelationships and provide sampling from deeper horizons. borehole in situ tests, installation of piezometer and laboratory analysis of the soil samples may also be needed in order to provide data for the detection of failure mechanisms, and the influence of seismic waves and ground water interaction causing rapid development of dolines in this area. it was suggested that site exploration covers the wider area in order to enable the production of a detailed subsidence susceptibility map. in addition, monitoring of the area should be established. monitoring should include periodic remote sensing, groundwater level monitoring and monitoring of ground shaking intensity. these data, with the results of the other aforementioned investifigure 11. the distribution of subsidence dolines in the wider mečenčani and borojevići area on the geological map (originally in the scale 1:5 000; mraz, 2005). g eologia c roatica pollak et al.: the preliminary inventory of coseismic ground failures related to december 2020 – january 2021 petrinja earthquake series 205 gations, should provide insight into the rates of doline development in time and their relationship to ground conditions. suffosion processes, enlarging and forming new subsidence dolines in this area are still rapidly progressing, therefore research in this area should be given a high priority in dealing with geological hazards induced by earthquakes. within the forthcoming winter and spring, when the hydrological maximum usually occurs in this area (peaks of both the precipitation and the groundwater levels), new dolines can be formed, especially if some stronger aftershocks occur when groundwater levels are high. locations of the dolines suggest preferential flow paths in the karstic underground, and these zones will be the main target of geophysical profiling (electrical tomography and refraction seismic). these preferential flow paths in karst aquifers are usually caused by fault or fracture zones where the rock mass is highly karstified. above these karstified rocks, suffosion of quaternary deposits is significantly stronger than in other areas, so the combination of karstification and suffosion weakens these zones, while the earthquake accelerates the whole process. it is important to emphasize that groundwater level (pressure) in the karstic aquifer is usually higher than that in the quaternary deposits overlying the aquifer, which also increases the suffosion at the soil/rock contact. 4.2. liquefied areas liquefaction is mainly traced by boiling sand phenomena at the surface (figure 5). according to the preliminary data, most of the phenomena are spotted in the recent alluvial sediments related to the rivers sava, kupa and glina (figure 2). the alluvium of these recent rivers is dominated by pure sands, only locally by silts. siltose or gravelly sands, and lenses of pure gravels are also observed (pikija et al., 1986). the material ejected at the surface is predominantly classified as pure sand, which is confirmed by granulometry laboratory analysis (figure 12). locally, liquefaction effects are registered in the flood sediments. these sediments are dominantly fine grained clayey and sandy silts or fine-grained sands (pikija et al., 1986). due to their depositional nature (sedimentation from an aqueous suspension after flooding), their thickness depends on the terrain configuration and is usually up to 5 m. the surface effects of liquefaction are not registered in the minor and thinner alluvium deposits of smaller rivers including the petrinjčica, moštanica and other streams (figure 2). namely, their alluvial sediments are dominated by gravels (pikija et al., 1986), coarser sediments less susceptible to liquefaction. the distances of the boiling sand occurrences from these rivers also confirms the strong relationship between liquefaction and the larger alluvial sedimentary bodies. namely, distances measured from the aforementioned rivers are up to 1000 metres. the exception is the area of the vinogradska street in petrinja, where the liquefied area also involves pliocene sediments in the base (clays, gravels and sands) (according to available geological map in the scale 1: 100 000). another isolated case of possible liquefaction in pliocene sediments is registered in posavci near kravarsko, situated far away from any significant river flow (> 8000 m). therefore, for these reasons, the possibility of liquefaction of saturated sandy layers in pliocene sediments should be studied in more detail. the preliminary conclusion is that liquefaction almost exclusively occurred in widespread and thicker alluvial sediments containing significant beds or lenses of loose and “pure” sand layers. considering all the collected data in the research area, favourable conditions for liquefaction are related to the sava, kupa and glina alluvium or floodplain sediments which, according to rough and preliminary estimations cover more than 100 km2 (figure 13). the presented map is based solely on current database records and existing geological data at the scale of 1:100.000 and should be considered as a rough estimation. detailed studies are needed in order to define liquefaction susceptibility zones and mitigation measures. as can be seen, liquefaction-induced lateral spreading and ground subsidence can cause considerable damage to civil infrastructure. in this area, lateral spreads frequently occurred on the fairly flat area alongside streams or river courses causing river bank failures. ground subsidence usually happened in the near vicinity of the river courses where loose sandy layers are of greater thickness and are completely saturated with water. this resulted in the settling of houses, buckling of roads, and subsidence of flood embankments. it is important to note that the settlement and tilting of some buildings is also observed in the postseismic period and even though some of these are marked as ‘usable’ from a structural point of view. their behaviour is strongly affected by the ground conditions and can lead to state limits being exceeded. it is important to point out that the occurrence of liquefaction in some layers is not necessarily associated with the damage of structures. if a thick layer of non-liquefiable soil exists near the ground surface, and if the thickness of the underlying layer of liquefied sand is low, then the damaging effects of liquefaction will not be manifested at the ground surface (ishihara, 1985). still, considering great potential for damage as a consequence of liquefaction and its related processes, it is suggested that more detailed engineering geological and geotechnical exploration is performed. the exploration should cover the whole croatian region that meets liquefaction-favourable conditions and are also zones of high seismicity. the aim of such a study should be the mitigation of, and preparedness for liquefaction-induced damage. there are many international researchers who have studied liquefaction potential and defined liquefaction-induced hazards. maps showing the degree of liquefaction susceptibility are based on the likely response of subsurface materials to seismic loading figure 12. granulometric diagram of sand boil material sampled at the surface in brest pokupski. the analysis is done in accordance with hrn en iso 178924:2016 norm. g eo lo gi a c ro at ic a geologia croatica 74/2206 (youd & perkins, 1987; kajihara et al., 2016). a study about the liquefaction potential of sediments in the zagreb area was presented by veinović et al. (2007), who also authored a doctoral thesis entitled evaluation of possibility for liquefaction susceptibility and setting bases for liquefaction zonation in croatia (veinović, 2007), which could be a good basis for starting research in potentially endangered zones. 4.3. landslides landslide locations are scattered across the research area but are mostly related to particular lithologies (figure 14), being predominantly observed in pl and pl-q sediments. both units are characterised by clays, sands and gravels, and are well known for frequent landslides in the much wider region. several landslides in loess sediments are recognised here, which are also observed in the wider kutina area. landslides on top of “rocky” m5, m4 and pc-e units are probably related to soil material in their weathe ring zones. the alluvial (a, ap) and diluvial (dpr) units are presented separately, because sliding processes on flat areas in these sediments are frequently related to liquefaction processes and lateral spreading along river banks, causing river bank failure (figure 14). factors to be considered in assessing the potential for earthquake-induced landslides, according to gonzález de vallejo & ferrer (2011) are the presence of unstable slopes or slopes in precarious states of stability prior to the earthquake, steep slopes, soils with low strength or metastable structures (quick clays, collapsible soils) and rock scarps with potential rockfall hazards. therefore, in estimations of coseismic landslide susceptibility, besides the usual parameters, the aforementioned additional factors should be considered. the authors’ opinion is that due to different geological medium and failure mechanisms, sliding and falling susceptibility should be analysed separately. as for other susceptibility maps, landslide susceptibility analysis should start with inventory. the reliable inventories are based on visual analysis of remote sensing derivates. besides, appropriate to the scale/details in which the map is prepared, a relevant geological map is essential. depending on the specific properties of the area in focus, additional factors and data are combined in order to produce a reliable landslide susceptibility map. until now in croatia, various landslide susceptibility maps at different scales were prepared by different engineering-geologists, but for figure 14. the proportional distribution of landslides in particular geological units. figure 13. rough and preliminary estimations of the area with favourable conditions for liquefaction processes (shaded blue). the estimation is based on recent surface processes caused by liquefaction (blue dots) and existing basic geological map in the scale 1: 100.000. g eologia c roatica pollak et al.: the preliminary inventory of coseismic ground failures related to december 2020 – january 2021 petrinja earthquake series 207 this region three maps are relevant. for the whole croatian territory, a small-scale landslide susceptibility map displays general susceptibility for large regions (podolszki et al., 2014; erak, 2018). regional sliding susceptibility map for the whole of sisakmoslavina county at the scale of 1: 100.000 has been prepared for the safearth project (bostjančić et al. 2021). rockfall susceptibility maps consider different input factors. for a regional approach, the rockfall inventory is essential. the analysis of large areas subjected to such processes is based on the identification of the rockfall source areas using remote sensing techniques. a detailed bare earth digital terrain model (dtm) obtained by lidar can help in defining rockfall source areas. using a detailed (1:5.000) geological map and the aforementioned remote sensing based inventory, it is possible to produce a reliable rockfall susceptibility map (toševski, 2018). such a map should indicate zones endangered by falling rocks triggered by intensive precipitation or earthquakes. the procedure for a more detailed rockfall threat assessment, for specific locations, require much more data and field work, and is described in bostjančić & pollak (2020). earthquakes and related natural geohazard processes cannot be prevented, but their effects on construction can be mitigated. therefore, the focus of geological experts is directed toward hazard identification and preventive measures. in order to undertake that successfully, systematic research and extensive studies of various geological hazards are essential. geological hazards are studied in different projects and their results are applied locally, but central inventories of the geohazard processes are not supported. national, open and sustainable databases are basic preconditions for the proper evaluation of geological hazards for the whole croatian territory. therefore, the initiative by the hgi (www.hgi-cgs.hr) for their existence and sustainability will hopefully be reinforced by responsible agencies in order to allow their growth and use. references avanić, r., kovačić, m., pavelić, d. & peh, z. (2018a): the neogene of hrvatsko zagorje.– in: tibljaš, d., horvat, m., tomašić, n., mileusnić, m. & grizelj, a. (eds.): 9th mid-european clay conference, conference book, field trip guide book, zagreb, 128–131. avanić, r., šimunić, a. & peh, z. (2018b): geology of the croatian zagorje region.– in: rman, n., marković, t. & brenčić, m. (eds.): 5. slovenski geološki kongres, post congress field trip book, ljubljana, p. 35. bačić, m., ivšić, t. & kovačević, m.s. (2020): geotechnics as an unavoidable segment of earthquake engineering.– građevinar, 72/10, 923–936, doi: 10.14256/ jce.2968.2020 bada, g., horváth, f., dövényi, p., szafian, p., windhoffer, g. & cloetingh, s. (2007): present-day stress field and tectonic inversion in the pannonian basin.– global and planetary change, 58, 165–180. doi: 10.1016/j.gloplacha.2007.01.007 basili, r., kastelic, v., demircioglu, m.b., garcia moreno, d., nemser, e.s., petricca, p., sboras, s.p., besana-ostman, g.m., cabral, j., camelbeeck, t., caputo, r., danciu, l., domac, h., fonseca, j., garcía-mayordomo, j., giardini, d., glavatovic, b., gulen, l., ince, y., pavlides, s., sesetyan, k., tarabusi, g., tiberti, m.m., utkucu, m., valensise, g., vanneste, k., vilanova, s. & wössner, j. (2013): the european database of seismogenic faults (edsf) compiled in the framework of the project share. http://diss.rm.ingv.it/share-edsf/share_ wp3.2_database.html, doi: 10.6092/ingv.it-share-edsf. bates, r.l. & jackson, j.a. (1980): glossary of geology american geological institute (agi).– falls church, 751 p. bell, f.g. (2007): engineering geology, second edition.– elsevier ltd., 575 p. bird, j.f. & bommer, j.j. (2004): earthquake losses due to ground failure.– engineering geology, 75/1, 147–179. doi: 10.1016/j.enggeo.2004.05.006 bommer, j.j. & rodríguez, c.e. (2002): earthquake-induced landslides in central america, eng. geol., 63, 189–220. doi: 10.1016/s0013-7952(01)00081-3 bostjančić, i. & pollak, d. (2020): rockfall threat assessment along railways in carbonate rocks in croatia.– bulletin of engineering geology and the environment, 79, 3921–3942. doi: 10.1007/s10064-020-01822-x. bostjančić, i., filipović, m., gulam, v. & pollak, d. (2021): regional-scale landslide susceptibility mapping using limited lidar-based landslide inventories for sisak-moslavina county, croatia. sustainability, 13, 4543. https://doi. org/10.3390/su13084543 caprari, p., della seta, m., martino, s., fantini, a., fiorucci, m. & priore, t. (2018): upgrade of the cedit database of earthquake-induced ground effects in italy.– italian journal of engineering geology and environment, 2, 23–39. doi: 10.4408/ijege.2018-02.o-02 dorren, l.k.a. (2003): a review of rockfall mechanics and modelling approaches.– progress in physical geography: earth and environment, 27/1, 69–87. doi: 10.1191/0309133303pp359ra. erak, m. (2018): karta podložnosti na klizanje republike hrvatske [landslide susceptibility map of the republic of croatia – in croatian].– unpubl. master’s thesis. faculty of mining, geology and petroleum engineering, university of zagreb, zagreb, 35 p. gonzález de vallejo, l.i. & ferrer, m. (2011): geological engineering.– crc press/balkema, 678 p. doi: 10.1201/b11745 gorum, t., fan, x., van westen, c.j., huang, r.q., xu, q., tang, c. & wang, g. (2011): distribution pattern of earthquake induced landslides triggered by the 12 may 2008 wenchuan earthquake.– geomorphology, 133, 3–4, 152–167. doi: 10.1016/j.geomorph.2010.12.030 govorčin, m., herak, m., matoš, b., pribičević, b. & vlahović, i. (2020): constraints on complex faulting during the 1996 ston–slano (croatia) earthquake inferred from the dinsar, seismological, and geological observations.– remote sensing, 12, 1157. doi: 10.3390/rs12071157 grizelj, a. (2004): mineraloške i geokemijske značajke gornjomiocenskih pelitnih sedimenata jugozapadnog dijela hrvatskog zagorja [mineralogical and geochemical characteristics of upper miocene pelitic sediments of the south-western part of hrvatsko zagorje – in croatian].– unpubl. master’s thesis, faculty of science, university of zagreb, zagreb, 118 p. halamić, j., belak, m., pavelić, d., avanić, r., filjak, r., šparica, m., brkić, m., kovačić, m., vrsaljko, d., banak, a. & crnko, j. (2019): osnovna geološka karta republike hrvatske mjerila 1 : 50.000 – požeška gora [basic geological map of the republic of croatia 1:50.000 – požeška gora – in croatian].– croatian geological survey, department of geology, zagreb. herak, d., herak, m. & tomljenović, b. (2009): seismicity and earthquake focal mechanisms in northwestern croatia.– tectonophysics, 465, 212–220. doi: 10.1016/j.tecto.2008.12.005 herak, d., herak, m., prelogović, e., markušić, s. & markulin, ž. (2005): jabuka island (central adriatic sea) earthquakes of 2003.– tectonophysics, 398, 167–180. doi: 10.1016/j.tecto.2005.01.007 herak, d., herak, m. & vrkić, i. (2017a): velika trešnja, seizmičnost i potresna opasnost na širem dubrovačkom području [great earthquake, seismicity and seismic hazard in the wider dubrovnik area – in croatian].– dubrovnik: časopis za književnost i znanost xxviii, 1, 5–18. herak, d., sović, i., cecić, i., živčić, m., dasović, i. & herak, m. (2017b): historical seismicity of the rijeka region (nw external dinarides, croatia) – part i: earthquakes of 1750, 1838 and 1904 in the bakar epicentral area.– seismological research letters, 88, 904–915. herak, d., živčić, m., vrkić, i. & herak, m. (2020): the međimurje (croatia) earthquake of 1738.– seismological research letters, 91, 1042–1056. doi: 10.1785/0220190304 herak, m., allegretti, i., herak, d., ivančić, i., kuk, v., marić , k., markušić , s. & sović , i. (2011): republika hrvatska, karta potresnih područja [republic of croatia, seismic hazard maps – in croatian].– university of zagreb, faculty of science, department of geophysics. http://seizkarta.gfz.hr/ karta.php. accessed 25 january 2021. in: eurocode 8: design of structures for earthquake resistance–part 1: general rules, seismic actions and rules for buildings. national annex.– croatian standards institute, p. 28. ishihara, k. (1985): stability of natural deposits during earthquakes.– in: proceedings of the eleventh international conference on soil mechanics and foundation engineering, san francisco, 12–16 august, 321–377. kajihara, k., pokhrel, r.m., kiyota, t. & konagai, k. (2016): liquefaction-induced ground subsidence extracted from digital surface models and its application to hazard map of urayasu city, japan.– in: the 15th asian regional conference on soil mechanics and geotechnical engineering, japanese geotechnical society special publication, 829–834. doi: 10.3208/jgssp.tc203-02. keefer, d.k. (1984): landslides caused by earthquakes.– bulletin of the geological society of america 95, 406–421. kovačić, m. (2004): sedimentologija gornjomiocenskih naslaga jugozapadnog dijela panonskog bazena. [sedimentology of the upper miocene deposits from the southwest part of the pannonian basin – in croatian].– unpubl. phd thesis, faculty of science, university of zagreb, 203 p. kranjc, a. (2013): classification of closed depressions in carbonate karst.– in: shroder, j. (editor in chief), frumkin, a. (ed.): treatise on geomorpholg eo lo gi a c ro at ic a geologia croatica 74/2208 ogy. academic press, san diego, ca, vol. 6, karst geomorphology, 104–111. doi: 10.1016/b978-0-12-374739-6.00125-1 krsnik, m. (2005): geofizička istraživanja područja pašinog vrela [geophysical research of the pašino vrelo spring area – in croatian].– unpubl. technical report, archive igh d.d., u 0255/05. kurečić, t. (2017): sedimentologija i paleoekologija pliocenskih viviparus slojeva vukomeričkih gorica [sedimentology and paleoecology of pliocene viviparus beds from the area of vukomeričke gorice – in croatian, with an english abstract].– unpubl. phd thesis, faculty of science, university of zagreb, 168 p. kurečić, t., kovačić, m. & grizelj, a. (submitted): mineral assemblage and provenance of the pliocene viviparus beds from the area of vukomeričke gorice (central croatia).– geologia croatica. kvasnička, p. & matešić, l. (2001): geotechnical data base for the city of zagreb and its application in site response analyses.– in: fourth international conference on recent advances in geotechnical earthquake engineering and soil dynamics, san diego, california, 11–15. kvasnička, p., matešić, l. & skračić, s. (1998): geotehnička podloga grada zagreba. [geotechnical basis of the city of zagreb – in croatian].– građevinar, 50/1, 119–127. larva, o., marković, t. & mraz, v. (2010): hydrodynamic and hydrochemical conditions at the groundwater source “pašino vrelo”, with focus on its development.– geologia croatica, 63/3, 299–312. doi:104154/gc.2010.24 majer, v. & lugović, b. (1985): metamorfne stijene u ofiolitnoj zoni banije, jugoslavija. ii. amfiboliti (metabaziti) [metamorphic rocks in the banija ophiolite zone, yugoslavia: ii.amphibolites (metabasites) – in croatian].– acta geologica jazu, 15/2, 25–49, zagreb. majer, v. (1984): metamorfne stijene u ofiolitskoj zoni banije, jugoslavija. i. metapeliti [metamorphic rocks in the banija ophiolite zone of banija, yugoslavia. i. metapelites – in croatian].– rad jazu, 41/1, 35–82, zagreb. mandic, o., kurečić, t., neubauer, t.a. & harzhauser, m. (2015): stratigraphic and paleogeographic significance of lacustrine mollusks from the pliocene viviparus beds in central croatia.– geologia croatica, 68/3, 179–207. doi: 10.4154/gc.2015.15 markušić, s., stanko, d., korbar, t., belić, n., penava, d. & kordić, b. (2020): the zagreb (croatia) m5.5 earthquake on 22 march 2020.– geosciences, 10, 252. doi: 10.3390/geosciences10070252 martino, s., prestininzi, a. & romeo, r.w. (2014): earthquake-induced ground failures in italy from a reviewed database.– natural hazards and earth system sciences, 14, 799–814. doi: 10.5194/nhess-14-799-2014 matešić, l. & kvasnička, p. (2007): geotechnical data management according to iso 9001.– in: cuellar et al. (eds): proceedings of the 14th european conference on soil mechanics and geotechnical engineering, madrid. mill press science publishers, 1715–1719. matešić, l., kvasnička, p. & mihalić, s. (2011): importance of data and process management in eurocode 7.– geofizika, 28/1, 99–107. mraz, v. (2005): vodoistražni radovi „pašino vrelo“ [hydrogeological investigations of the pašino vrelo spring – in croatian].– unpubl. technical report, archive of the croatian geological survey, 88/05. mraz, v., larva, o. & marković, t. (2007): izvorište „pašino vrelo“. zaštitne zone za novi zdenac spb pv – 01/06 i vodocrpilište „pašino vrelo“. [pašino vrelo spring – sanitary protection zones for the new extraction well spb pv – 01/06 and the spring itself – in croatian].– unpubl. technical report, archive of the croatian geological survey, 64/07. norris, g., gahir, z. & siddharthan, r. (1998): an effective stress understanding of liquefaction behaviour.– environmental and engineering geoscience, 4, 93–101. pamić, j. (2002): the sava–vardar zone of the dinarides and hellenides versus the vardar ocean.– eclogae geologicae helvetiae, 95, 99–113. pavelić, d. & kovačić, m. (2018): sedimentology and stratigraphy of the neogene rift-type north croatian basin (pannonian basin system, croatia): a review.– mar. petrol. geol., 91, 455–469. doi: 10.1016/j.marpetgeo.2018.01.026 pikija, m. (1986): osnovna geološka karta sfrj 1:100.000. tumač za list sisak. [basic geological map of sfry 1:100.000, geology of the sisak sheet – in croatian].– institut za geološka istraživanja, zagreb, savezni geol. zavod, beograd, 55 p. pikija, m. (1987): osnovna geološka karta sfrj 1:100.000 list sisak [basic geological map of sfry 1:100.000, sisak sheet – in croatian].– geol. zavod, zagreb, savezni geol. zavod, beograd. podolszki, l., pollak, d., gulam, v. & miklin, ž. (2014): development of landslide susceptibility map of croatia.– in: lollino g. et al. (eds.): engineering geology for society and territory – volume 2, 947–950. doi: 10.1007/978-3319-09057-3_164 prestininzi, a. & romeo, r. (2000): earthquake-induced ground failures in italy.– engineering geology, 58/3–4, 387–397. doi: 10.1016/s0013-7952(00)00044-2 raffaelli, p. & magdalenić z. (1970): metamorphic and magmatic rocks in the gvozdansko-brezovo polje area. banija.– bull. sci. cons. acad. yougosl., (a), zagreb, 15/9-10, 313–314. rodríguez, c.e., bommer, j.j. & chandler, r.j. (1999): earthquake-induced landslides: 1980–1997.– soil dynamics and earthquake engineering, 18, 325–346. doi: 10.1016/s0267-7261(99)00012-3 saftić, b., velić, j., sztanó, o., juhász, g. & ivković, ž. (2003): tertiary subsurface facies, source rocks and hydrocarbon reservoirs in the sw part of the pannonian basin (northern croatia and south-western hungary).– geologia croatica, 56/1, 101–122. šavor novak, m., uroš, m., atalić j., herak, m., demšić, m., baniček, m., lazarević, d., bijelić, n., crnogorac, m. & todorić, m. (2020): zagreb earthquake of 22 march 2020 – preliminary report on seismologic aspects and damage to buildings.– građevinar, 72, 10, 843–867 schmid, s.m., fügenschuh, b., kounov, a., maţenco, l., nievergelt, p., oberhänsli, r., pleuger, j., schefer, s., schuster, r., tomljenović, b., ustaszewski, k. & van hinsbergen, d.j. (2020): tectonic units of the alpine collision zone between eastern alps and western turkey.– gondwana research, 78, 308–374. doi: 10.1016/j.gr.2019.07.005 schmitt, r.g., tanyas, hakan, nowicki, jessee, m.a., zhu, jing, biegel, k.m., allstadt, k.e., jibson, r.w., thompson, e.m., van westen, c.j., sato, h.p., wald, d.j., godt, j.w., gorum, tolga., xu, chong, rathje, e.m. & knudsen, k.l. (2017): an open repository of earthquake-triggered ground-failure inventories.– u.s. geological survey data release collection, data series 1064, accessed june 26. doi: 10.5066/f7h70db4. šikić, k. (2014a): osnovna geološka karta rh 1:100.000, list bosanski novi [basic geological map of republic croatia 1:100.000, bosanski novi sheet – in croatian].– croatian geological survey, zagreb. šikić, k. (2014b): osnovna geološka karta rh 1:100.000, tumač za list bosanski novi [basic geological map of republic croatia 1:100.000, geology of the bosanski novi sheet – in croatian].– croatian geological survey, zagreb, 111 p. šimunović, a. & hećimović, i. (1998): geološka i hidrogeološka istraživanja bliže okolice pašinog vrela [geological and hydrogeological study in the vicinity of “pašino vrelo”– in croatian].– unpubl. technical report, archive of the croatian geological survey, 88/98. tomljenović, b. & csontos, l. (2001): neogene-quaternary structures in the border zone between alps, dinarides and pannonian basin (hrvatsko zagorje and karlovac basins, croatia).– international journal of earth sciences, 90, 560–578. doi: 10.1007/s005310000176 torbar, j. (1882): izvješće o zagrebačkom potresu [the report on zagreb earthquake – in croatian]. – jazu, zagreb, 141 p. toševski, a. (2018): podložnost porječja rijeke dubračine površinskim geodinamičkim procesima [susceptibility of the dubracina river basin to the superficial geodynamical processes – in croatian].– unpubl. phd theses, faculty of mining, geology and petroleum engineering, university of zagreb, 251 p. u.s. geological survey (2021): earthquake glossary at url: https://earthquake.usgs. gov/learn/glossary/ ustaszewski, k., herak, m., tomljenović, b., herak, d. & matej, s. (2014): neotectonics of the dinarides-pannonian basin transition and possible earthquake sources in the banja luka epicentral area.– journal of geodynamics, 82, 52–68. doi: 10.1016/j.jog.2014.04.006 ustaszewski, k., kounov, a., schmid, s.m., schaltegger, u., krenn, e., frank, w. & fügenschuh, b. (2010): evolution of the adria‐europe plate boundary in the northern dinarides: from continent‐continent collision to back‐arc extension.– tectonics, 29, tc 6017, 1–34. doi: 10.1029/2010tc002668 ustaszewski, k., schmid, s.m., lugović, b., schuster, r., schaltegger, u., bernoulli, d., hottinger, l., kounov, a., fügenschuh, b. & schefer, s. (2009): late cretaceous intra oceanic magmatism in the internal dinarides (northern bosnia and herzegovina): implications for the collision of the adriatic and european plates.– lithos, 108, 106–125. doi: 10.1016/j.lithos.2008.09.010 varnes, d.j. (1978): slope movement types and processes.– in: schuster, r.l. & krizek, r.j. (eds): landslides: analysis and control, vol. 176. national academy of sciences, trb special report, 11–33. veinović, ž. (2007): ocjena mogućnosti pojave likvefakcije i definiranje osnove za likvefakcijsko zoniranje na teritoriju republike hrvatske. [assessment of the possibility of liquefaction occurrence and defining the basis for liquefaction zoning on the territory of the republic of croatia – in croatian].– unpubl. phd theses, faculty of mining, geology and petroleum engineering, university of zagreb, 330 p. veinović, ž., domitrović, d. & lovrić, t. (2007): pojava likvefakcije na području zagreba u prošlosti i procjena mogućnosti ponovne pojave tijekom jačeg potresa [historical occurrence of liquefaction in zagreb area and estimation of reoccurrence in case of another strong earthquake – in croatian].– rudarskogeološko-naftni zbornik, 19, 111–120. waltham, a.c. & fookes, p.g. (2003): engineering classification of karst ground conditions.– quarterly journal of engineering geology and hydrogeology, 36, 101–118. doi: 10.1144/1470-9236/2002-33 williams, p. (2004): dolines.– in: gunn, j. (ed.): encyclopedia of caves and karst science.– fitzroy dearborn, new york, ny, and london, 304–310. youd, t.l. & hoose, s.n. (1978): historic ground failures in northern california associated with earthquakes.– usgs professional paper, 993, 177 p. youd, t.l. & perkins, j.b. (1987): map i-127-g.– us geological survey, washington, dc. 2019 | 72 / special issue | 57–69 | 14 figs. | 2 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the fracture system of a coal reservoir provides an important space for cbm adsorption, diffusion, and migration (laubach et al., 1998; pashin & groshong, 1998; dawson & es­ terle, 2010; mostaghimi et al., 2017). estimation of the fracture system of coal-bearing strata has been applied widely in cbm exploration in many coal basins of the usa, canada, aus­ tralia and china (moore, 2012). characteristics of the fracture system in coal seams are among the driving factors for the explo­ ration and development of cbm (li et al., 2013; zhang et al., 2017). moderately developed fracture systems can improve the primary permeability of the coal seam, while an over-developed fracture system leads to the breakage of the coal’s structure, which brings unfavourable influence to drilling, hydraulic frac­ turing, and production of cbm (ayers, 2002). therefore, it is important to be able to define the studied coal’s fracture system as reliably as possible. however, this is not always possible and can be demonstrated by the following two aspects: firstly, there are practical difficulties in studying the subject as coal seams generally occur deep underground, where the fractures cannot be observed and measured directly. therefore, it is difficult to obtain data on the whole fracture system in a coal seam. secondly, research methods are limited. existing studies on fracture systems mainly observe pores and fractures by sampling hand specimens or rock and coal cores from boreholes or distinguish and predict coal fractures utilizing geophysical methods or mathematical simulation (yao et al., 2009; koroncz et al., 2017). however, due to a high degree of heterogeneity in coal seams, the the prediction of structural fractures in coal seams of the kuba coalfield, china: an application for coalbed methane (cbm) recovery development zhou zhang1,2,3, min zhou1, yun-xing cao1,2,3, bao-an xian1,2,3 and di gao1,2,* 1 school of resources and environment, henan polytechnic university, jiaozuo, china; (*corresponding author: gaodi@hpu.edu.cn) 2 collaborative innovation center of coalbed methane and shale gas for central plains economic region, henan province, jiaozuo, china 3 henan international joint laboratory for unconventional energy geology and development, jiaozuo, china doi: 10.4154/gc.2019.26 abstract the structural fracture system in a coal reservoir enables coalbed methane (cbm) percolation and migration. it plays an important role in cbm exploration and exploitation (recovery) development. nearly vertical strata with mesozoic bituminous coal seams in the central part of the kuba coalfield of the xinjiang province in china were studied using large-scale mapping of the structural fractures on the surface, and a using a technique for comparing and analyzing sections of the underground coal mine. this investigation verified that similar structural fractures are developed in the underground coal seams as those on the surface, and surrounding rocks represent the same tectonic layer. meanwhile, a corresponding relationship between the characteristics of the development of fractures – including the growth directions and degree of development of fractures in coal seams and the surrounding rocks was established. based on this, the research presents a new method for predicting a pattern of fractures in coal seams and the coal structure, respectively. finally, the study area was divided into zones with dense, moderate and un-developed fractures. the method should be applicable in various coal-and-gas engineering fields, for example the prediction of fractured zones in coal seams, the prediction of coal structure, and for projecting the well arrangement in the exploration and development of economic recovery of cbm. observational and geophysical data of a few samples cannot re­ flect the development characteristics of the fracture system in the coal seams of the whole development zone. the fracture system in a coal seam is composed of pores, microcracks, endogenous fractures (face cleats and butt cleats) and structural fractures, in which the pore diameter is of nannometre dimensions, the length of microfractures is of micrometre dimensions, the length of en­ dogenous fractures (face cleats and butt cleats) is of centimetre dimensions, and the structural fractures range to metre dimen­ sions and more. in the whole fracture system, the structural frac­ ture is the main channel of coalbed methane migration and the main contributor of its permeability. it is known that tectonic stress is the primary reason for the generation of fractures in coal seams and their surrounding rocks, while the joint influences of lithology, stratum thickness and tec­ tonic stress affect the degree of fracture development (mckee et al., 1988; solano-acosta et al., 2007; datta, 2016). within the coal, the fracture (cleat) system is also dependant on coal rank (brook et al., 2016; weniger et al., 2016; busse et al., 2017) lithotype composition and mineral admixtures (dawson & esterle, 2010; widera, 2014). as to the area where joints are densely developed in the out­ crop strata at the surface, the joints in the same area in the strata deep underground are usually more compact than those in the strata of adjacent regions (wheeler, 1980; chen et al., 2017; zhao et al., 2019). that is to say that under the influence of tec­ tonic stress, the fractures generated in strata with different lithologies, thicknesses, and tectonic positions closely correspond article history: manuscript received february 01, 2019 revised manuscript accepted august 28, 2019 available online december 20, 2019 keywords: coal seams and surrounding rocks, mesozoic bituminous coal, structural fracture system, corresponding relations, coalbed methane (cbm), kuba coalfield, china g eo lo gi a c ro at ic a geologia croatica 72 / special issue58 (laubach et al., 1998; rawnsley et al., 1998; bai & pol­ lard, 2000; arlegui & simón, 2001). therefore, the development degree of the underground coal seam fractures can be predicted by investigating the development degree of fractures in the outcropped strata at the surface. based on this understand­ ing, a new method of structural fracture study can be used to evaluate the coalbed methane exploration development zone at the surface. the large-scale mapping of structural fractures and the fine comparison and analysis of the underground coal seams were performed on the cbm development zone of the kuba coalfield in xinjiang, china. in this process, parameters including the de­ velopment characteristics of the fracture systems, the predomi­ nant development directions and the linear density of the frac­ tures at the ground surface, the underground coal seams, and the surrounding rocks were acquired and compared. meanwhile, the corresponding relationship between the fractures in the coal seams and the surrounding rocks was established with the aim of applying the knowledge to the exploration and development of the cbm, especially to predict the development degree of the fractures and the coal’s structure in underground coal seams. 2. geological setting the kuba coalfield of xinjiang, china is located in the southern foothills of the tianshan fold belt (fig. 1). in terms of the regional tectonic setting, the kuba coalfield ispart of the kuba depression. it is located in the northern monoclinal zone of the kuba depres­ sion and bears the same tectonic deformation as the whole kuba depression (liang et al., 2003; feng et al., 2018; lai et al., 2019). the mesozoic strata of the kuba coalfield have undergone five stages of palaeotectonic stress, as its coal-bearing strata are the lower series of the jurassic system. these five tectonic phases form the present tectonic framework, including the early and late yanshanian, and early, middle and late himalayan. the average maximum principal compressive stress direction of the early yan­ shanian tectonic stress field is about 310°, while that of the late yanshanian tectonic stress field is about 0° and the average maximum palaeo-effective stress value is 39.3 mpa. in the early hi­ malayan period, the tectonic stress field was compressed in a nearly n-s direction. during this period, the average horizontal maximum principal compressive stress direction was about 350°, and the average maximum palaeo-effective stress value was 55.7 mpa. the maximum principal compressive stress direction in the middle himalaya is nearly north-south, and the average maxi­ mum palaeo-effective stress value is 63.6 mpa during this period. the maximum principal compressive stress direction of the late himalayan tectonic stress field is nearly n-s horizontal compres­ sion, and the average maximum palaeo-effective stress value is 79.4 mpa, which indicates that the late himalayan tectonic stress figure 1. location of the study area and stratigraphic column of the jurassic coal-bearing strata. g eologia c roatica zhang et al.: the prediction of structural fractures in coal seams of the kuba coalfield, china: an application for coalbed methane (cbm) ... 59 field was the most intense compressional period in the kuba de­ pression, and finally forms a nearly e-w thrusting knappe tec­ tonic framework in this area. except for the early yanshanian, when the maximum principal stress was in a nw-se direction, other stages were a result of maximum principal stress in a nearly n-s direction. under the stress of several stages, many similar and closely related fractures were generated within the surround­ ing rocks and the coal seam reservoirs (rawnsley et al., 1998; arlegui & simón, 2001). the middle part of the coalfield is a monocline structure in­ clined towards the south. the strata trend nearly ew trended. the tendency of strata is 78° to 184°, and local strata are inverted. the dip angle ranges from 80° to 89°, and the strata are nearly vertical. the coal-bearing strata in this region belong to the taliqike formation of the lower jurassic series (j1t) and are mainly composed of glutenites (massive sandstones and conglomerates), gritstones (coarseand angular-grained siliceous sandstones), mediumand fine-grained sandstones, siltstones, mudstones, and coal seams. affected by multiple stages of tectonic stress, frac­ tures are well developed in these strata. limited by natural conditions, the development of the frac­ tures in coal seams and surrounding rocks cannot be observed directly in ordinary cbm development zones. however, the nearly vertical coal seams and the well-preserved coal seam out­ crops at the surface of the mining area provide excellent condi­ tions for observing and analyzing the corresponding relationships between the fracture systems in coal seams and surrounding rocks (fig. 2). 3. research methods 3.1. the high-precision structural fracture mapping technique in this study, a high-precision structural mapping technique was used with special emphasis on studying the fracture system. at the surface, the spacing of the observation points ranged from 100–150 m, and the density of the observation points was ap­ proximately 100 per square kilometre. the reference standard was “coalfield geological mapping regulations” (the minis­ try of land and mineral resources of the pr of china, 2014). in addition, there are coal mines under ex­ ploitation in the study area, which were convenient for the obser­ vation of fracture systems in the underground coal strata. in the 3515 horizontal roadway of the spacing, the observation points ranged from 1–10 m on the coal wall. working faces are exca­ vated manually in the kuba coal mines. a fine anatomical com­ parison technique was used to study the internal and external fractures in the underground coal reservoir (figure 3). using surface high-precision structural fracture mapping in the cbm development block of the kuba coalfield, the macrogeometric parameters of joint fractures of the surrounding rocks were studied including ① dip angle; ② direction; ③ cutting relationships; ④ combination form; ⑤ scale; and ⑥ filling de­ gree. figure 2. outcrop of coal and surrounding rock in the field. g eo lo gi a c ro at ic a geologia croatica 72 / special issue60 3.2. the fine observation and dissection technique of underground coal reservoirs fine observation and dissection of coal reservoirs in the surface and underground were performed. this technique is mainly used to observe and dissect the structural fractures of a coal reservoir in a coal mine roadway. the observations ranged from about every 10 metres to tens of metres. the direction, density, and fill­ ing of structural fractures were observed in detail, and samples of coal and rock were collected to be tested in the laboratory. based on this, three major characteristics most closely related to the coal reservoirs were observed including: ① the spatial dis­ tribution characteristics of the studied coal reservoir; ② the structural characteristics of the coal; and ③ the physical charac­ teristics of the rocks. the development characteristics of frac­ tures in the coal reservoirs were studied at both macroscopic and microscopic scales. 3.3. micromorphological observations in order to describe the shape, length, aperture, and connectivi ty of micro-fractures coal and rock samples were studied using following procedures (karacan & okandan, 2000): opti­ cal microscopy (lv100 pol microscope with an mps 60 pho­ tometer system), and scanning electron microscopy (fei quanta 250 sem) equipped with a high performance x-ray energy spectrometer that simultaneously carried out qualitative and semi-quantitative analysis of the elements of the surface layer of each sample to provide a comprehensive analysis of morpho­ logy and the chemical composition. the coal samples were di­ vided into two groups of coal slices, and the processes were con­ ducted as follows. the first group (for optical microscopy) was incised and polished to 30 × 30 mm cubes, of which the surface was divided into 9 equal zones of 10 × 10 mm used to determine the fracture amount and type in a sequence. in the second group (for the sem), one side of the polished coal sample surface was gold-plated to increase the electrical conductivity. in order to observe the microscopic fracture system in coal, samples of the a1, a3, a5, a7, a8, and a9 coals were collected. the development of microfractures is restricted by the internal components of the coals which are predominantly detrovitrinite and telovitrinite (after the iccp, 1998 classification) plus mineral admixtures. development of microfractures usually occurs in matrix vitrinite (detrovitrinite) and homogenous vitrinite (telo­ vitrinite). when observed under a microscope, microfractures in the a1 coal sample were only weakly developed, and microfrac­ tures were mostly filled with inorganic minerals. the microfrac­ tures extended 1×104–1×107 nm, and the width was approximately 1×103–1×104 nm. the connectivity between the matrix pores and fracture system was not good, which is unfavourable for the de­ velopment of coalbed gas migration. the a3 coal microfractures had good connectivity between the matrix pores and fracture system. powder was readily produced where microfractures de­ veloped, especially in the intersections of microfractures in dif­ ferent directions, and the coalbed methane migration pathway was easily blocked by the coal powder. additionally, the cutting phenomenon of microcracks could be seen. the microfractures of a5 coal were not developed, the connectivity between the ma­ trix pores and fracture system was good, powder production was low in the microfractures, and pyrite occasionally filled microfractures. the a7 coal microfractures were less developed, and the connectivity was not good; the microfractures were mostly filled with calcite. the a8 and a9 coal microfractures were less developed, and the matrix pores and fracture system were well con­ nected, which is favourable for the migration of coalbed metha ne. the microfractures clearly showed cutting and dislocations, some microfractures were filled with vein quartz (figure 4). 4. results and discussion 4.1. tectonic fracture occurrence the exogenic fractures are generated due to the exogenic tectonic stress, which acts in the same way to the formation of the joint fractures in both the surrounding rocks and the coal. that is, when the stress is greater than the ultimate strengths of the sur­ rounding rocks and coal, fractures are generated. in the research area, shear fractures are mainly developed. the development morphology of the exogenic fractures in coal and the joints in the surrounding rocks are similar, so the jointed surrounding rocks were taken here to analyze the force conditions of the exogenic fractures. the study shows that the shear fractures develop along a surface in the surrounding rocks, which is not only related to the intensity of the shear stress at the surface, but also to the nor­ mal stress of the surface. the rocks are unlikely to fracture along the acting surfaces of the maximum shear stress but rather along the surface where the resultant force of the shear stress and the figure 3. coal reservoir in underground coal mine. a – development of two groups of structural fractures in coal seams b – development of two groups of endogenous fractures in coal seams c – development of one group of endogenous fractures in coal seams d and e – fragmentation of coal structure in coal seams g eologia c roatica zhang et al.: the prediction of structural fractures in coal seams of the kuba coalfield, china: an application for coalbed methane (cbm) ... 61 normal stress is the smallest, which is in accordance with the mohr-coulomb failure criterion (yazdani bejarbaneh et al., 2015; hackston & rutter, 2016): fτ = t0 + f sn (1) where fτ is the shear strength of the shearing surface of the rock, t0 is the inherent shear strength of the rock, which equals the cohesion c. besides, f and f are the internal friction coefficient of the rock and the internal friction angle respectively, f = t g j. in addition, sn is the normal stress in the shear fracture plane (pressure stress is considered as normal). in figure 5. to the right, σ1 is the maximum principal stress, σ3 is the minimum principal stress, ϕ is the angle between the maximum principal stress and the force that can generate the fractures. the angle between the direction of the outer normal of the shear fracture plane and the maximum principal stress σ1: 45 2 ϕα = + (2) therefore, the maximum and the minimum stresses respec­ tively bisect the acute angle and the obtuse angle between the two conjugate fracture planes, as shown in fig. 5. ( ) ( )1 3 1 3 1 1 cos 2 2 2nσ σ σ σ σ α= + + − (3) ( )1 3 1 sin 2 2fτ σ σ α= − (4) if the above equations are substituted into the coulomb de­ termination equation, it can be obtained that: ( ) ( )( )0 1 3 1 3 1 cos 2 sin 2 2 2 f fτ σ σ σ σ α α= − + − − − (5) where a is the angle between the normal direction of the shear fracture plane and s1, also known as the fracture angle. through the transformation equation (5) becomes: ( ) ( ) 1 1 2 21 32 2 0 1 1 2 2 f f f fσ στ     = + − − + +        (6) figure 4. microfractures in kuba coalfield. g eo lo gi a c ro at ic a geologia croatica 72 / special issue62 equation (6) is the failure criterion based on s1 and s3. if the principal stresses s1 and s3 satisfy this equation, shear fractures are formed. while conducting the large-scale mapping on the structural fractures in the research area, it was discovered that the structural fractures are developed in all directions of the strata, but are domi­ nated by three directions, namely, nnw-sse, nne-ssw, and s-n (fig. 6. left side). the dip angle of each degree in a rock for­ mation is developed, and there is no dominant direction (fig. 6 right side). according to the statistical analysis, it was observed that the degree of fracture development in the research area is closely re­ lated to the lithology and the stratum thickness. 4.2. the lithology of the surrounding rocks and the fracture density based on the mapping of outcropping structural fractures in the field and the fine contrast technique of coal reservoirs in the un­ derground coal mine workings, a total of 4405 joints were meas­ ured in the study area. lithology has a significant influence on the degree of development of the fractures: when the particles and pore volumes of rock are decreased, the fracture generated be­ come compact. when the rock strength increases, even a small strain can give rise to breakage and deformation of the fracture, leading to the widely developed fractures in the rocks with low porosity and fine particles. this research collected the measured data in different observation points of the research area and se­ lected the strata of different lithologies with the thickness of 20 cm as the standard. within these considering the average lin­ ear density, 3.6, 4.2, 4.9, 5.3, 6.3, and 8.0 fractures were developed per metre in the fine conglomerate, gritstone, medium sandstone, fine sandstone, and mudstone respectively (fig. 7). it can be clearly concluded from the graph in fig. 7 that the finer-grained the rock is, the greater the linear density of the fracture. in con­ trast, the coarser-grained the rock is, the smaller the linear den­ sity of the joint fracture. 4.3. the thickness of the surrounding rocks and the fracture density joint density varies with the stratum thickness. generally speak­ ing, when an external force acts on rocks of the same lithology but of different thicknesses, the joints in the thin layers have small distances and great density. since the strata in the research area are well exposed at outcrop, the development of the tectonic joints at different thicknesses can be observed in most of the observa­ tion points. the linear densities of the fractures developed in different lithologies and the stratum thicknesses in all observation points of the research area were collected, among which, those of grit­ stone were applied as an example to illustrate the relationship between the stratum thickness and the linear density of the joint fractures. as shown in figure 8b, an increase in the stratum figure 5. the forces the joint fractures suffer in surrounding rocks. figure 6. rose and dip distribution. g eologia c roatica zhang et al.: the prediction of structural fractures in coal seams of the kuba coalfield, china: an application for coalbed methane (cbm) ... 63 thickness of the gritstone exhibits an exponential decrease in the linear density of the joint fractures according to the function y = 33.57x-0.58 and with a correlation coefficient of r2=0.73. in the function, x represents the stratum thickness (m), and y is the lin­ ear density of the fractures. the latter (fractures per metre) can be expressed as pieces per metre (pieces/m). meanwhile, a simi­ lar relationship was also found in the conglomerate, medium sandstone, fine sandstone, siltstone and mudstone (figure 8a, c, d, e, f). therefore, with the increase of the stratum thickness, the linear density of the fractures decreases exponentially, when the stratum thickness is more than 1 m, the linear density of the fracture tends to be a fixed value. figure 7. average linear density of structural fractures. figure 8. relationship between the stratum thickness and the linear density of fractures for different lithologies; a: conglomerate; b: gritstone; c: medium sandstone; d: fine sandstone; e: siltstone; f: mudstone. g eo lo gi a c ro at ic a geologia croatica 72 / special issue64 the relationship between the stratum thickness of the sur­ rounding rocks and the fracture density: the conglomerate fitting formula: y = 26.35x–0.49 r2 = 0.89 (7) the gritstone fitting formula: y = 33.57x–0.58 r2 = 0.73 (8) the medium sandstone fitting formula: y = 43.54x–0.61 r2 = 0.86 (9) the fine sandstone fitting formula: y = 87.48x–0.83 r2 = 0.72 (10) the siltstone fitting formula: y = 108.72x–0.77 r2 = 0.85 (11) the mudstone fitting formula: y = 172.92x–0.88 r2 = 0.79 (12) 4.4. the fractures in the coal seam outcrops the outcropping of coal in the study area (figs. 2 and 9) is well preserved and can be used to observe directly the development characteristics of the structural fractures, such as the develop­ ment of the density of structural fractures and the development directions of the structural fractures. based on the statistics of a large number of measured data, it was found that the outcropped coal seams a5 and a7 dip towards the s (azimuth 175°) with an inclination angle of 85°. statistical analysis of endogenous and exogenous fractures in a5 and a7 coal seams was carried out, which can be divided into different types of coal lithotypes, and the thickness, attitude and density of coal layers were counted, as shown table 1. the development of the fractures in the coal seam outcrops shows that the density of exogenic fractures of the a5 coal seam figure 9. the development of the fractures in the outcropped coal seams of the research area; a: exogenic fractures of the a5 coal seam; b: endogenic fractures of the a5 coal seam; c: fractures on the surface of the a7 coal seam; d: fractures on the floor of the a7 coal seam. table 1. the development of the fractures in the outcropped coal seams of the research area. coal seam coal lithotypes thickness/ cm exogenetic fractures endogenic fractures attitude density piece/m attitude density piece/m a5 semidull coal 40 110°∠23° 10 semibright coal 10 266°∠75° 285°∠5° 140 120 semibright coal 45 108°∠25° 6 275°∠79° 158°∠75° 160 140 semibright coal 15 118°∠28° 6 275°∠79° 158°∠75° 160 140 dirt band 5 118°∠28° 252°∠46° 10 10 semibright coal 25 110°∠23° 6 275°∠79° 158°∠75° 220 180 bright coal 60 110°∠23° 6 275°∠79° 158°∠75° 220 180 a7 semibright coal 65 105°∠27° 252°∠46° 14 13 182°∠85° 138°∠7° 220 95 semidull coal 45 100°∠23° 268°∠73° 25 20 172°∠88° 110 g eologia c roatica zhang et al.: the prediction of structural fractures in coal seams of the kuba coalfield, china: an application for coalbed methane (cbm) ... 65 ranges from 6–10 pieces/m, with an average density of 6.8 pieces/m (table 1). the density of exogenic fractures of the a7 coal seam ranges from 13–25 pieces/m, while the average density is 18 pieces/m. endogenic fracture densities of the a5 and a7 coal seams ranges from 110–220 pieces/m, with an average den­ sity of 160 pieces/m. 4.5. the cleats in the coal seam outcrops according to the macroscopic coal compositions in separate strata, the development of the exogenic and endogenic fractures in each stratum were measured. in the outcrops of the coal seams a5 and a7, exogenic fractures mainly extend to the nnw-sse, nne-ssw and s-n direction. this is coincident with the growth directions of the fractures in the surrounding rocks. the endo­ genic fractures trend mainly s-n and sw-ne where the lengths of the face cleats and the butt cleats, are 5-15 cm and 0.5-2 cm, respectively. the face cleats and the butt cleats are perpendicular to bedding and intersect perpendicularly, the face cleats are dominant, while the butt cleats are shorter and connect them (close, 1993; laubach et al., 1998; gresley, 2009; weniger et al., 2016). the development of the exogenic fractures (joints) in both the surrounding rocks and the coal seams usually ends at a stra­ tum surface, which is called the boundary of the mechanical lay­ ers. the height of joints between two boundaries of the mechanical layer is the thickness of the layer, which can either be the thickness of a single stratum or of multiple strata. the exogenic fractures in coal seams are generally developed in the small strata of coal which are petrograpically different by their lithotype com­ position, varying from dull, semi-dull, semi-bright and bright coal lithotypes. the directions of the fractures of different strata of coal are coincident, as shown in figure 9(a) and figure 9(c). as demonstrated in figure 9(b) and figure 9(d), the development of the fractures in the surrounding rocks is similar to that in the coal seams. the endogenic fractures are developed adequately in the coal seams of the research area with a maximum linear den­ sity of 220 pieces/m. 4.6. the fractures in the underground coal seams the heading face of the a5 coal seam was applied as the under­ ground observation point, which is located in the western part of the +2000 horizontal roadway in the dawanqi coal mine of the kuba coalfield. the coal seam is buried 210 m underground with a thickness of 8.2 m, in which 3.1 m of coal could be observed (figure 10). the a5 coal seam is inclined southward with a dip angle of 83° (fig. 10). the coal is mainly fragmented but undeformed. it exhibits an integral coal structure. the linear density and the length of the endogenic fractures are 200 pieces/m, respectively, while the occurrence is divided into two groups, namely, the group with a dip of 273°/83°, and 232°/41°. exogenic fractures can be divided into four groups. the exogenic joints are dip to 271° and 115° with inclinations of 86° and 44° with a linear density of 2-4 pieces/m. these exogenic joints are characterized by their preferable extensibility, regular development, and almost com­ plete extent through the visual area. exogenic joints with a dip of 20°/30°, are slightly deformed with the linear density reaching 6 pieces/m. in addition, a few joints are developed in the group with a dip of 90°/ 65° (figure 10). the observed thickness of the a7 coal seam underground is about 2 m, and the roof and the floor are both visible. the roof and the floor are composed of the glutenites and the grey-black mudstones respectively, and the coal is a dark black colour. in macro level, the coal rock is half-duration, which has an integral coal structure and is composed of the fragmented coal of primary structure. three groups of regularly developed exogenic joints are inclined to 281°, 273°, and 41° with dip angles of 35°, 54°, and 60° respectively. there is one group of endogenic fractures, which are inclined to 221° with a dip angle of 60° and a linear density of 10 pieces/m (figure 11). figure 10. observation map of coal body structure in a5 coal seam. g eo lo gi a c ro at ic a geologia croatica 72 / special issue66 according to the observed results from the underground, the fractures in the coal seams extend n-s and nne-ssw, with few trending nnw-sse, which is basically coincident with the re­ sults observed at the surface. according to the analysis, fractures with the same direction are found in the surrounding rocks and the coal seams on the ground, as well as in the roof, floor and seams of the underground coal seams. therefore, it verifies that when the coal seam and the surrounding rock of the same tectonic layer suffer from the same tectonic stress, the joint fractures gen­ erated in them are similar. 4.7. measured section the middle part coal mine of the kuba coalfield is characterized by approximately vertical coal seams and surrounding rocks, as well as the well-preserved coal seam outcrops at the surface. therefore, it provides excellent conditions for observing and analyzing the corresponding relationship between the fracture sys­ tems in the coal seams and the surrounding rocks. besides, the corresponding relationship of the fracture development in the coal seams and the surrounding rocks can be established visually by analyzing multiple sections. multiple sections were measured in the research area. the primary mineable coal seams of a5 and a7 and their roofs and floors outcropped in these sections, which provides favourable conditions for investigating the corresponding relationship be­ tween the fractures in the coal seams and the surrounding rocks. taking one section for example, relevant data are illustrated in figure 12. and table 2. one section that contains the primary mineable coal seams of a5 and a7, mudstone, siltstone, fine sandstone, medium sand­ stone, gritstone, and fine conglomerate was measured. by measuring the attitude and linear density of the structural fractures as well as the thickness of each stratum, the corresponding relation­ ship between the exogenous fractures in the coal mines and the surrounding rocks can be visually observed. as shown in table 2, multiple groups of joints are developed in each stratum, and only the occurrences of the fractures in the dominated directions are illustrated. figure 13. shows that the thickness of strata in the measured section is inversely proportional to the density of structural frac­ tures, that is, with the increase in the thickness of strata, the den­ sity of structural fractures decreases. this relationship exists in coal seams, fine conglomerate, medium sandstone, siltstone, and mudstone, and is consistent with the previous mapping results. figure 11. observation map of coal body structure in a7 coal seam. figure 12. measured section in the research area. table 2. the measured section data statistics. number lithology thickness/ cm dominant direction of attitude density piece/m number lithology thickness/ cm dominant direction of attitude density piece/m 1 mudstone 190 280° 55° 8 10 coal seam 170 272° 48° 34 2 coal seam 820 287° 44° 23 11 mudstone 70 278° 45° 11 3 fine sandstone 450 294° 47° 3 12 coal seam 140 271° 40° 38 4 coal seam 400 281° 52° 29 13 mudstone 400 275° 80° 6 5 medium sandstone 60 307° 21° 2 14 coal seam 100 278° 68° 39 6 gritstone 500 300° 20° 4 15 mudstone 180 273° 65° 7 7 fine conglomerate 430 305° 40° 3 16 coal seam 420 273° 54° 15 8 medium sandstone 1440 304° 35° 1 17 fine conglomerate 350 301° 35° 2 9 siltstone 160 276° 54° 4 figure 13. the relation between thickness and density of measured section. g eologia c roatica zhang et al.: the prediction of structural fractures in coal seams of the kuba coalfield, china: an application for coalbed methane (cbm) ... 67 4.8. the direction of the fractures in the coal seams and the surrounding rocks as observed in the measured data, the dominant direction of the fractures in the coal seams is basically in accordance with that in the surrounding rocks. the occurrences of the dominant fractures in mudstone, siltstone, and fine sandstone are coincident with those in the coal seams, with a mere 10° variance in orientation. despite the dominant joints in medium sandstone, gritstone and fine conglomerate presenting the same occurrence, the occur­ rence differs about 20° from that in the coal seams considering the dominant direction, to even more than 30° in some strata. therefore, the direction of the structural fractures in the coal seams can be predicted accurately by investigating the fractures developed in mudstone and siltstone. the structural fractures de­ veloped in the coal seams are mainly trended to nne-ssw and n-s directions. 4.9. the corresponding relationship concerning the degree of fracture development the linear density of fractures developed in strata (coal seams) is a key parameter for predicting the fragmentation of the coal structure. owing to fractures in different directions being found in one observation point, the sum of the fractures developed within the circle with a radius for 2 m was applied as the number of fractures at a particular observation point. afterward, the re­ lationship between the stratum thickness and the linear density of fractures in the different lithologies was established by inves­ tigating the data of all the observation points in the research area. the relationship between rock thickness and density has been described, as in formulae (7)-(12). the relationship between the stratum thickness of the coal rocks and the fracture density can be exppressed as: the coal seam fitting formula: y = 645.74x–0.33 r2 = 0.85 (13) in the formulae from (7)-(12), x represents the stratum thick­ ness of each lithology in cm, y indicates the linear density of the fractures in different lithologies (pieces/m). the aforementioned formulae demonstrate that the linear density of fractures is merely related to the stratum thickness. meanwhile, since small tectonics such as faults and folds are not developed in the research area, the development of the fractures located in different tectonic structures is ignored here. therefore, the established correspond­ ing relationship between the linear density of the fractures in the coal seam and the lithology is given as follows: when the thickness of the mudstone is the same as that of the coal seams, we obtain, ycoal = 645.74xcoal -0.33 and ymud = 172.92xcoal -0.88, namely, ycoal/ ymud= 645.74xcoal -0.33/172.92xcoal -0.88 therefore, the following relationships can be obtained: the corresponding relationship between the fractures in the mudstone and the coal seams: y coal = 645.74xcoal 0.55 xmud –0.88 (14) the corresponding relationship between the fractures in the siltstone and the coal seams: ycoal = 645.74xcoal 0.44 xsilt –0.77 (15) the corresponding relationship between the fractures in the fine sandstone and the coal seams: ycoal = 645.74xcoal 0.50 xfine –0.83 (16) the corresponding relationship between the fractures in the medium sandstone and the coal seams: ycoal = 645.74xcoal 0.28 xmed –0.61 (17) the corresponding relationship between the fractures in the gritstone and the coal seams: ycoal = 645.74xcoal 0.25 xgrit –0.58 (18) the corresponding relationship between the fractures in the conglomerate and the coal seams: ycoal = 645.74xcoal 0.16 xcon –0.49 (19) formulae (13)-(19) exhibit the corresponding relationship be­ tween the fractures in the coal seams and other strata in the re­ search area. therefore, ycoal represents the linear density of the fractures in the coal seams (piece/m). xcoal indicates the thickness of the underground coal seam corresponding to the observation point on the ground (m), which can be calculated through the con­ tour map of the coal seam thickness. xsilt (etc.) denotes the thick­ ness of different strata observed at the observation point on the ground (m). by substituting the data measured in the field into the for­ mulae (13)-(19), the linear density of the fractures in the under­ ground coal seams can be calculated, which can be utilized to divide the degree of fracture development in coal seams. 4.10. the prediction of fracture development in the coal seams by studying the surface outcrop of the approximately vertical coal seams and the exposed underground seams in the research area, the development range of the linear density of the fractures in the undeformed coal and the fragmentized coal, from which cbm can be explored, was determined visually and quantita­ tively. after calculating the linear density of the fractures in the coal seams of the research area using the formulae (13)-(19), the research area was divided into zones with dense, moderate and un­developed fractures. the zones with dense fractures present a high density of the joint fractures and destroyed coal structure in the coal seam, which therefore is endowed with poor stability. the correspond­ figure 14. the prediction of the fracture development in the research area. g eo lo gi a c ro at ic a geologia croatica 72 / special issue68 ing coal structures are the fragmented coal and mylonitic coal. since the over-developed exogenic fractures are expected to de­ stroy the seal of the coal seams, these type of zones should not be considered in the exploration and development of cbm. in the zones with moderate fractures, the fracture density is medium compared with those of the dense zone and the un-de­ veloped zone with an integral and stable coal structure. corre­ spondingly, fragmented coal is found in this category of zone. meanwhile, the endogenic fractures of the coal seam are inter­ linked by the exogenic fractures, therefore improving the perme­ ability of the coal seam. the zones with un-developed fractures are characterized by a low fracture density, an integral and stable coal structure which is the undeformed coal. given that the exogenic fractures are not developed in the coal seams, the permeability of the coal seam is therefore barely improved, which poses no threat to the storage of cbm (figure 14). by analyzing the corresponding relationship between the growth directions of the fractures in the coal seams and the sur­ rounding rocks, the growth direction of dominant fractures in the research area can be determined, which is also the direction of the principal permeability of the coal seam. therefore, the growth di­ rection of the main fractures is required to be considered while de­ termining the well pattern, good drilling locations and well spacing. 5. conclusions large-scale mapping of the structural fractures on the ground and the technology for finely and comparatively analyzing the sections of underground coal seams were applied when studying the approximately vertical coal seams of the kuba coalfield in xinjiang, china. meanwhile, a new method was put forward for predicting the fractures in coal seams and the coal structure. (1) the corresponding relationship between the development characteristics including the direction and degree of fracture de­ velopment in the coal seams and the surrounding rocks was es­ tablished in the kuba coalfield of xinjiang. the research pre­ dicted the development characteristics of the fractures in the coal seams of the research area and divided the area into zones with dense, moderate and un-developed fractures. it should be noted that this method is applicable to areas where the surrounding rock and coal seam belong to the same tectonic layer and the surround­ ing rock is exposed at the surface. (2) studies regarding the corresponding relationship between the fractures in coal seams and the surrounding rocks can be em­ ployed to predict the fractures in coal seams and the coal struc­ ture and arrange a good pattern for the exploration and develop­ ment of cbm. acknowledgment this study was financially supported by the national oil and gas major projects, grant number 2017zx05064-002, national sci­ ence foundation of china, grant number 41872147; phd foun­ dation of henan polytechnic university, grant number b201766. we have found lots of useful guidelines in the comments that improved our manuscript. references arlegui, l. & simon, j.l. (2001): geometry and distribution of regional joint sets in a non-homogeneous stress field: case study in the ebro basin (spain).– journal of structural geology, 23/2–3, 297–313. doi: 10.1016/s0191-8141(00)00097-3 ayers, w.b. (2002): coalbed gas systems, resources, and production and a review of contrasting cases from the san juan and powder river basins.– american asso­ ciation of petroleum geologists bulletin, 86, 1853–1890. bai, t. & pollard, d.d. (2000): fracture spacing in layered rocks: a new explana­ tion based on the stress transition.– journal of structural geology, 22/1, 43–57. doi: 10.1016/s0191-8141(99)00137-6 brook, m.s., hebblewhite, b.w. & mitra, r. (2016): cleat aperture-size dis­ tributions: a case study from the late permian rangal coal measures, bowen basin, australia.– international journal of coal geology, 168, 186–192. doi:10.1016/j.coal.2016.11.009. busse, j., de dreuzy, j.r., galindo torres, s., bringemeier, d. & scheuermann, a. (2017): image processing based characterisation of coal cleat networks.– international journal of coal geology, 169, 1–21. doi:10.1016/j. coal.2016.11.010. chen, s., tang, d., tao, s., xu, h., li, s., zhao, j., ren, p. & fu, h. (2017): insitu stress measurements and stress distribution characteristics of coal reservoirs in major coalfields in china: implication for coalbed methane (cbm) develop­ ment.– international journal of coal geology, 182, 66–84. doi:10.1016/j. coal.2017.09.009. close, j.c. (1993): natural fractures in coal.– american association of petroleum geologists bulletin, 38, 119–132. datta, d.r. (2016): coal, cleat system.– encyclopedia of mineral and energy policy, 1–4. dawson, g.k.w. & esterle, j.s. (2010): controls on coal cleat spacing.– interna­ tional journal of coal geology, 82, 213–218. doi:10.1016/j.coal.2009.10.004. feng, j., ren, q. & xu, k. (2018): quantitative prediction of fracture distribution us­ ing geomechanical method within kuqa depression, tarim basin, nw china.– journal of petroleum science and engineering, 162, 22–34. doi:10.1016/j.pet­ rol.2017.12.006. gresley, w.s. (2009): theory for “cleat” in coal-seams.– geological magazine, 9, doi:10.1017/s0016756800196074. hackston, a. & rutter, e. (2016): the mohr-coulomb criterion for intact rock strength and friction – a re-evaluation and consideration of failure under polyaxi­ al stresses.– solid earth, 7, 493–508. doi:10.5194/se-7-493-2016. karacan, c.o. & okandan, e. (2000): fracture/cleat analysis of coal from zon­ guldak basin (northwestern turkey) relative to the potential of coalbed methane production.– int. journal of coal geology, 44, 109–125. doi: 10.1016/s01665162(00)00004-5 koroncz, p.j., péter, á., lemberkovics, v. & fedor, f. (2017): pore characterization, acoustic and permeability measurements on core plug triplets, from the miocene tótkomlós (calcareous marl) formation of the pannonian-basin, hungary.– geologia croatica, 70, 87–92. doi:10.4154/gc.2017.09. lai, j., li, d., wang, g., xiao, c., hao, x., luo, q., lai, l. & qin, z. (2019): earth stress and reservoir quality evaluation in high and steep structure: the low­ er cretaceous in the kuqa depression, tarim basin, china.– marine and petro­ leum geology, 101, 43–54. doi:10.1016/j.marpetgeo.2018.11.036. laubach, s.e., marrett, r.a., olson, j.e. & scott, a.r. (1998): characteristics and origins of coal cleat: a review.– international journal of coal geology, 35, 175–207. doi: 10.1016/s0166-5162(97)00012-8 li, s., tang, d., pan, z., xu, h. & huang, w. (2013): characterization of the stress sensitivity of pores for different rank coals by nuclear magnetic resonance.– fuel, 111, 746–754. doi:10.1016/j.fuel.2013.05.003. liang, d., zhang, s., chen, j., wang, f. & wang, p. (2003): organic geochemistry of oil and gas in the kuqa depression, tarim basin, nw china.– organic ge­ ochemistry, 34, 873–888. doi:10.1016/s0146-6380(03)00029-9. mckee, c.r., c, b.a. & a, k.r. (1988): stress-dependent permeability and porosity of coal and other geologic formations,– spe production & operations, 3, 81–91. moore, t.a. (2012): coalbed methane: a review.– international journal of coal geology, 101, 36–81. doi:10.1016/j.coal.2012.05.011. mostaghimi, p., armstrong, r.t., gerami, a., hu, y., jing, y., kamali, f., liu, m., liu, z., lu, x., ramandi, h.l., zamani, a. & zhang, y. (2017): cleat-scale characterisation of coal: an overview.– journal of natural gas science and engineering, 39, 143–160. doi:10.1016/j.jngse.2017.01.025. pashin, j.c. & groshong, j.r.h. (1998): structural control of coalbed methane production in alabama.– international journal of coal geology, 38, 89–113. doi: 10.1016/s0166-5162(98)00034-2 rawnsley, k.d., peacock, d.c.p. & rives, t. (1998): joints in the mesozoic sediments around the bristol channel basin.– journal of structural geology, 20, 1641–1661. doi: 10.1016/s0191-8141(98)00070-4 solano-acosta, w., mastalerz, m. & schimmelmann, a. (2007): cleats and their relation to geologic lineaments and coalbed methane potential in penn­ sylvanian coals in indiana.– international journal of coal geology, 72, 187–208. doi:10.1016/j.coal.2007.02.004. weniger, s., weniger, p. & littke, r. (2016): characterizing coal cleats from optical measurements for cbm evaluation.– international journal of coal geology, 154–155, 176–192. doi:10.1016/j.coal.2015.12.005. wheeler, r.l. (1980): cross-strike structural discontinuities: possible exploration tool for natural gas in appalachian overthrust belt.– american association of pe­ troleum geologists bulletin, 64, 2166–2178. g eologia c roatica zhang et al.: the prediction of structural fractures in coal seams of the kuba coalfield, china: an application for coalbed methane (cbm) ... 69 widera, m. (2014): what are cleats? preliminary studies from the konin lignite mine, miocene of central poland.– geologos, 20, 3–12. doi:10.2478/log­ os-2014-0001. yao, y., liu, d., tang, d., tang, s., huang, w., liu, z. & che, y. (2009): frac­ tal characterization of seepage-pores of coals from china: an investigation on per­ meability of coals.– computers & geosciences, 35, 1159–1166. doi:10.1016/j. cageo.2008.09.005. yazdani bejarbaneh, b., jahed armaghani, d. & mohd amin, m.f. (2015): strength characterisation of shale using mohr–coulomb and hoek– brown criteria.– measurement, 63, 269–281. doi:10.1016/j.measure­ ment.2014.12.029. zhang, r., liu, s. & wang, y. (2017): fractal evolution under in situ pressure and sorption conditions for coal and shale.– sci rep, 7, 8971. doi:10.1038/s41598-01709324-9. zhao, j., tang, d., lin, w., qin, y. & xu, h. (2019): in-situ stress distribution and its influence on the coal reservoir permeability in the hancheng area, eastern mar­ gin of the ordos basin, china.– journal of natural gas science and engineering, 61, 119–132. doi:10.1016/j.jngse.2018.09.002. 2020 | 73/3 | 177–195 | 13 figs. | 1 tab. | 1 suppl. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the majority of upper miocene to pliocene (pannonian in the central paratethyan regional stratigraphic terminology, see hilgen et al., 2012) sediments of the pannonian basin system ­accumulated­in­the­brackish­lake­pannon­and­in­the­fluvial­feeder­ systems.­they­can­reach­a­thickness­of­over­6­km­and­represent­ the­time­interval­between­~11.6-2.6­ma.­in­spite­of­their­substantial­volume,­their­stratigraphic­subdivision­has­been­problematic­ for a long time, mostly as a result of the laterally prograding architecture­ of­ the­ basin­ fill­ (magyar,­ 2004;­magyar­&­ geary,­2012).­moreover,­the­subdivision­of­lake­pannon­sediments­ evolved­ independently­ in­ the­ neighbouring­ countries­ within­the­pannonian­basin­system,­although­the­lithostratigraphic­units­are­continuous­across­political­boundaries.­significant progress in cross-boundary correlation of the stratigraphic schemes­has­been­achieved­in­some­parts­of­the­basin­(e.g.­pig correlation of upper miocene-pliocene lake pannon deposits across the drava basin, croatia and hungary krisztina sebe1, marijan kovačić2, imre magyar3,4, krešimir krizmanić5, marko špelić6, dijana bigunac7, mária sütő-szentai8, ádám kovács9, andrea szuromi-korecz10, koraljka bakrač6, valentina hajek-tadesse6, tamara troskot-čorbić5 and orsolya sztanó9 1 university of pécs, department of geology and meteorology, 7624 pécs, ifjúság ú. 6, hungary; (sebe@gamma.ttk.pte.hu) 2 university of zagreb, faculty of science, department of geology, 10000 zagreb, horvatovac 95, croatia; (mkovacic@geol.pmf.unizg.hr) 3 mol hungarian oil and gas plc., 1117 budapest, október huszonharmadika utca 18., hungary; (immagyar@mol.hu) 4 mta-mtm-elte research group for paleontology, budapest, hungary 5 ina -oil company, plc., exploration & production, exploration & upstream portfolio development, lovinčićeva 4, 10 000 zagreb, croatia; (kresimir.krizmanic@ina.hr; tamara.troskot-corbic@ina.hr) 6 croatian geological survey, department of geology, 10000 zagreb, sachsova 2, croatia; (mspelic@hgi-cgs.hr; kbakrac@hgi-cgs.hr; tadesse@hgi-cgs.hr) 7 ina -oil company, plc., exploration & production, field development, v. holjevca 10, zagreb, croatia; (dijana.bigunac@ina.hr) 8 7300 komló, május 1 utca 7., hungary; (szentai.maria@gmail.com) 9 eötvös loránd university, department of geology, 1117 budapest, pázmány péter sétány 1/c; (konformista@caesar.elte.hu, sztano@caesar.elte.hu) 10 mol group e&p laboratory, 1039 budapest, szent istván út 14., hungary; (kaszuro@mol.hu) doi: 10.4154/gc.2020.12 abstract upper miocene to pliocene (pannonian) sediments of the pannonian basin system accumulated in the brackish lake pannon and the fluvial feeder systems, between 11.6-2.6 ma. their stratigraphic subdivision has been problematic for a long time due to the laterally prograding architecture of the basin fill and the historically independently evolving stratigraphic schemes of the neighbouring countries. we correlated the lithostratigraphic units of the lake pannon deposits between hungary and croatia in the drava basin, using lithological, sedimentological and palaeontological data from boreholes and outcrops, and seismic correlation. the croatica and medvedski breg formations in croatia correspond to the endrőd fm. in hungary, comprising shallow to deep water, open lacustrine, calcareous to argillaceous marls. the andraševec fm. in croatia corresponds to the szolnok and algyő fms. in hungary, consisting of sandstones and siltstones of turbidite systems and of clay marls deposited on the shelf-break slope. the nova gradiška fm. in croatia is an equivalent of the újfalu fm. in hungary, built up of a variety of lithologies, including sand, silt, clay and huminitic clay, deposited in deltaic environments. the pluska fm. in croatia corresponds to the zagyva fm. in hungary, consisting of variegated clays, silts, sands and lignites, deposited in alluvial and fluvial environments. coarse-grained (sand, gravel) basal layers are assigned to the kálla and békés fms. and the sveti matej member of the croatica fm. coarse-grained intercalations within the deep-water marls belong to the dorozsma member of the endrőd fm. in hungary, and to the bačun member of the medvedski breg fm. in croatia. sediment transport and lateral accretion of the shelf edge in the drava basin took place from the n, nw, and w, to the s, se, and e, respectively. according to the biostratigraphic and chronostratigraphic analyses, the oldest shelf-break slopes in the mura basin are more than 8 ma old, whereas the youngest ones in the southeasternmost part of the drava basin may be pliocene in age (younger than 5.3 ma). thus, the 180 km long and at least 700 m deep drava basin was transformed into a fluvial plain during the last 3.5 million years of the miocene. ott­&­radivojević,­2010;­sztanó­et­al.,­2016),­but­considerable­further­work­is­needed­to­obtain­a­stratigraphic­system­ applicable to the entire pannonian basin system. in­the­past­decades­there­have­been­several­efforts­aimed­at­ correlating the miocene sediments of croatia and hungary (saftić­et­al.,­2003;­hećimović­et­al.,­2010;­malvić­&­ cvetković,­2013).­the­need­for­this­is­well­demonstrated­by­ malvić­&­cvetković­(2013),­who­called­attention­to­the­fact­ that­the­otherwise­lithologically­similar­upper­miocene­formations­appear­in­the­stratigraphic­charts­as­time-transgressive­units­ in­hungary­but­as­units­with­synchronous­boundaries­in­croatia.­ in­the­framework­of­the­recent­hungarian-croatian­bilateral­project „stratigraphy and correlation of upper miocene – pliocene sediments­along­the­croatian-hungarian­border”,­we­aimed­to­ correlate the lithostratigraphic scheme of lake pannon deposits between­hungary­and­croatia­in­the­drava­basin,­a­deep­subarticle history: manuscript received april 27, 2020 revised manuscript accepted august 24, 2020 available online october 26, 2020 keywords: stratigraphy, correlation, upper miocene, pannonian, drava basin g eo lo gi a c ro at ic a geologia croatica 73/3178 basin in the sw part of the pannonian basin system. the fact that­the­drava­basin­covers­a­significant­proportion­of­the­distribution­area­of­lake­pannon­deposits­in­croatia­and­that­several­ upper miocene key sections are located in this region adds special­ importance­ to­ the­ area.­here­we­ present­ the­ correlated­ scheme,­the­definitions­of­the­stratigraphic­units­harmonised­between­the­two­countries­and­provide­field­and­borehole­examples­ of the typical appearance of the units. using seismic correlation and­biostratigraphic­dating­from­organic-walled­microplankton­ and­molluscs,­we­offer­temporal­limits­to­the­deposition­of­the­ given­units. 2. geological setting the­drava­basin­(fig.­1)­formed­as­a­result­of­early­-­middle­miocene­extension­(prelogović­et­al.,­1998).­above­the­palaeomesozoic­basement­the­basin­is­filled­by­nearly­7­km­of­cenozoic­ sediments­(horváth­et­al.,­2006).­in­most­of­the­basin­and­its­ surroundings the syn-rift succession began in the eggenburgian or­ottnangian,­with­terrestrial,­fluvial­and­lacustrine­clastics­in­ the­lower­miocene­and­continued­with­marine­deposits­in­the­ middle­miocene,­both­intercalated­with­volcanics,­mostly­pyroclastics­(hámor,­1970;­chikán,­1991;­lučić­et­al.,­2001;­ saftić­ et­ al.,­ 2003;­ nagymarosy­&­ hámor,­ 2012;­ malvić­&­cvetković,­2013;­pavelić­&­kovačić,­2018).­ in­the­area­of­the­northwestern­drava­basin­and­in­the­mura­basin, the oldest cenozoic rocks are of oligocene age and marine sedimentation persisted during the early and middle miocene. upper­miocene­–­quaternary­deposits­of­the­drava­basin­attain­ a­thickness­of­more­than­5­km­(fig.­1).­they­accumulated­in­the­ brackish lake pannon, the related marshes, and in the pliocene to­modern­fluvial­system­following­the­lake. upper miocene sediments crop out in the mountains bordering­the­drava­basin:­in­kalnik,­bilogora,­papuk­and­krndija­in­ north croatia on the southern and in the mecsek mts. on the northern­side­(fig.­1).­these­mountains­represent­basement­highs­ and­in­contrast­with­continuous­sedimentation­in­the­basin,­they­ emerged­from­lake­pannon­during­one­or­more­time­intervals­in­ the late miocene, thus their succession contains sedimentary gaps below,­within­and­above­the­lake­pannon­deposits­(kleb,­1973;­ kovačić­&­grizelj,­2006;­kovačić­et­al.,­2011;­sebe­et­ al.,­2013;­sztanó­et­al.,­2015).­no­upper­miocene­outcrops­are­ known­in­the­villány­hills­in­hungary.­however,­remnants­of­ most­probably­lake­pannon­sediments­preserved­in­the­shallow­ subsurface­in­intramountain­valleys­and­elevated­karstic­cavities­ (rakusz­&­strausz,­1953;­dezső­et­al.,­2007)­suggest­that­ this­area­was­flooded­as­well­for­at­least­some­time­during­the­late­ miocene. in­the­marginal­areas­surrounding­the­drava­basin,­sedimentation­across­the­sarmatian-pannonian­boundary­was­continuous­ in­the­deepest­part­of­small­sub-basins,­while­basement­highs­underwent­moderate­uplift­and­denudation­as­a­result­of­the­socalled­“post-sarmatian­inversion­event”­(saftić­et­al.,­2003;­ horváth­et­al.,­2006;­tomljenović­&­csontos,­2001).­ within­the­drava­basin­itself,­the­existence­of­sarmatian­sediments­has­not­been­proven­with­fauna­yet,­only­in­the­nw­in­the­ mura-zala­basins­(kőrössy,­1989;­horváth­et­al.,­2018).­ lake pannon deposits of the study area accumulated during the post-rift­phase­of­basin­evolution­(pavelić,­2001;­horváth­ et­al.,­2006;­balázs­et­al.,­2016).­after­this­subsidence-dominated­interval,­basin­inversion­started­in­the­latest­miocene,­coevally­with­the­still­ongoing­lacustrine­deposition,­and­is­still­active­today­(tomljenović­&­csontos,­2001;­csontos­et­ al.,­2002;­konrád­&­sebe,­2010;­van­gelder­et­al.,­2015). 3. methods the lithology, sedimentology and fossils of the target deposits were­investigated­in­the­field­and­in­cores­in­both­countries.­in­ order to identify and correlate lithostratigraphic and biostratigraphic­units­over­the­entire­drava­basin,­a­181­km­long­composite­seismic­section­was­constructed­parallel­to­the­nw-se­trendfigure 1. the drava basin and its surroundings, with the depth of upper miocene pliocene lacustrine and fluvial sediments. base pannonian surface from horváth et al. (2012). edb: eastern drava basin; mosl.: moslavačka gora; pg: požeška gora; srb: republic of serbia; wdb: western drava basin. g eologia c roatica sebe et al.: correlation of upper miocene-pliocene lake pannon deposits across the drava basin, croatia and hungary 179 ing­axis­of­the­basin­(fig.­1).­this­section­connects­the­key­wells­ legrad­ (leg)-1j,­severovci­ (sev)-1,­ferdinandovac-1duboka­ ­(f-1d),­péterhida­(phida)-1,­terezino­polje­(tp)-1,­felsőszentmárton­ (fel)-i,­zaláta­(zal)-1,­dravica­(dra)-1,­krunoslavlje­(kru)-2­and­ sječe­(sj)-2,­and­crosses­the­drava­river­and­the­croatian-hungarian­state­boundary­several­times.­in­addition­to­this­master­ profile­(fig.­7),­four­n-s­directed­crosslines­with­lengths­of­55,­ 49,­41­and­31­km,­respectively,­were­also­compiled­(figs.­1,­8).­ key­wells­iharosberény­(ih)-i,­vízvár-észak­(víz-é)-4,­vízvárs­(víz-s)-1,­potony-1,­and­donja­bukovica­(db)-1­and­-2­were­ connected­into­the­network­through­these­sections.­lithological­ and­biostratigraphic­data­from­the­key­wells­were­obtained­from­ well­logs­and­well­reports,­and­these­were­projected­into­the­seismic­network.­time/depth­functions­for­well­to­seismic­tie­were­ taken­from­the­databases­of­mol­and­ina.­additional­scattered­ biostratigraphic­data­from­larger­distances­were­correlated­to­this­ seismic­network­via­seismic­correlation. 4. lithostratigraphic schemes in croatia and hungary in croatia three main lithostratigraphic schemes are in use today for upper miocene deposits of the northern and eastern part of the country. earlier­studies­divided­the­succession­into­the­‘croatica’,­ ‘banatica’,­‘abichi’­and­‘rhomboidea­beds’,­while­pliocene­deposits­were­described­as­belonging­to­the­‘paludina­beds’­(croatian­geological­survey,­2009;­pikija,­2009;­basch,­ 2009)­fig.­2.­this­division,­ introduced­originally­by­jenko­ (1944),­was­primarily­based­on­the­superposition­of­leading­mollusc­taxa,­where­the­‘croatica’­and­‘banatica­beds‘­were­traditionally­attributed­to­the­“lower­and­upper­pannonian”,­while­ the­‘abichi’­and­‘rhomboidea­beds’­represented­the­“lower­and­ upper­pontian”,­respectively.­this­division­did­not­take­into­account that the spatial and temporal distribution of molluscs is highly dependent­on­changes­of­the­depositional­environment­(magyar­ &­geary,­2012).­furthermore,­it­has­since­been­shown­that­the­ pontian­stage,­originally­defined­in­the­euxinian­(black­sea)­basin,­was­erroneously­correlated­into­the­pannonian­basin­system­ (e.g.­mandic­et­al.,­2015).­nevertheless,­this­scheme­is­still­in­ use­in­croatia,­especially­in­petroleum­exploration­wells. the­two­other­systems­are­more­lithology-based.­they­have­ been­invented­for­the­entire­neogene­succession,­separately­for­ subsurface­and­surface­sediments.­an­older­system­introduced­ by­šimon­(1966,­1980)­and­updated­later­by­velić­(2007)­is­ used­for­subsurface­sediments­and­is­based­on­well­and­seismic­ data­(fig.­2).­in­this­system­the­lithostratigraphic­units­still­have­ the­chronostratigraphic­meaning­as­well,­they­were­defined­as­ equivalents­of­ (sub)stages,­neglecting­ the­ time-transgressive­ character­of­the­units.­in­addition,­for­historical­reasons­different­ names­exist­for­concurrent­units­in­different­parts­of­the­basins.­ this­system­has­long­been­used­in­the­drava­basin,­with­separate­ lithostratigraphic­schemes­for­the­western­(wdb)­and­the­eastern­(edb)­parts­of­the­basin­(šimon,­1966,­1980)­(fig.­2).­due­ to­the­aforementioned­weaknesses­of­the­first­division,­a­second­ system­has­been­created­in­the­past­thirty­years­during­surveying­ related­to­the­construction­of­the­geological­map­of­the­republic­ figure 2. informal upper miocene and pliocene units and lithostratigraphic schemes used for subsurface rocks in the eastern and western drava basin and in the mura basin in croatia. the concept behind these schemes does not distinguish between bioand lithostratigraphy and geochronology, therefore it is recommended that they are abandoned. (after rögl (1996) and magyar et al. (1999)) (j en ko (1 94 4) lu či ć et a l. ( 20 01 )) (after šimon (1980), saftić et al. (2003) and malvić & cvetković (2013)) g eo lo gi a c ro at ic a geologia croatica 73/3180 of­croatia.­new­lithostratigraphic­units­in­this­system­are­defined­ and named according to the international stratigraphic guide (murphy­&­salvador,­1999).­the­names­of­these­units­represent the recommendation of the national committee for stratigraphy and are used on recently published geological maps of the­republic­of­croatia­(map­sheets­for­the­slavonia­area:­filjak­et­al.,­2016a,­2016b;­halamić­et­al.,­2019).­the­unification­ of lithostratigraphic units for the territory of croatia is currently in progress. within this process, the names of certain pannonian lithostratigraphic­units­described­from­other­parts­of­croatia­have­ been­adopted­to­the­drava­basin­based­on­the­similar­lithology­ and related depositional setting. for­upper­miocene­and­pliocene­sediments­exposed­at­the­ surface,­the­scheme­contains­six­lithostratigraphic­units­of­formation­rank,­described­in­detail­below­(kovačić,­2004;­filjak­ et­ al.,­ 2016a,­ 2016b;­ kovačić­ &­ pavelić,­ 2017;­ halamić­et­al.,­2019)­(fig.­3).­in­addition,­locally­derived­clastic­sediments­are­classified­into­different­units­in­different­parts­ of the stratigraphic column. the surface distribution of these formations­was­outlined­by­mapping­in­the­hrvatsko­zagorje­region­ and­the­medvednica­mts.­in­nw­croatia,­and­along­the­northern­ margin­of­the­sava­basin­in­the­požeška­gora­mts.­and­dilj­gora­ mts.­in­the­eastern­croatian­region­of­slavonia.­geological­mapping of the mentioned deposits has not yet been carried out in the krndija,­papuk­and­bilogora­mts.­however,­as­a­result­of­terrain­ prospecting and recording of detailed geological sections, all the above­formations­have­been­identified­in­these­areas­(kovačić,­ 2004;­kovačić­&­pavelić,­2017). similarly­to­croatia,­various­stratigraphic­schemes­developed­for­individual­basins­and­also­for­basin­margins­used­to­exist­in­hungary­as­well.­the­standardisation­of­the­system­began­ with­the­work­of­juhász­(1994),­who­proposed­a­general,­genetically based scheme for all sedimentary basins of hungary. this­became­widely­accepted­and­led­to­significant­harmonisation,­but­basin­sediments­were­still­treated­separately­from­those­ cropping­out­ at­ the­present­margins­ (juhász,­1998;­korpásné­hódi,­1998).­the­past­two­decades­have­brought­progress­in­recognizing­that­except­for­the­oldest­formations­(békés,­ endrőd­and­kálla­fms.)­ indicating­ transgression­of­ the­ lake­ ­(sztanó­et­al.,­2010),­all­other­deposits­uniformly­reflect­the­ in­filling­process.­therefore­a­basin-wide­correlation­of­deep,­ open-water­mudstones,­turbidite­systems,­shelf­slope­mudstones­ and­deltaic­to­fluvial­successions­can­easily­be­carried­out­­(e.g.­ sztanó­et­al.,­2013a,­2013b,­2016;­csillag­&­sztanó,­ 2015a, b), regardless of their present topographic position, i.e. buried­in­deep­basin­interiors­or­exposed­along­margins­of­the­ present­hills.­the­formations,­both­with­their­litho-­and­biofacies,­ follow­the­evolution­of­the­depositional­environments,­governed­ by­the­long-term­normal­regression­interrupted­by­minor­flooding­events­or­local­variations­in­sediment­input.­official­formation descriptions accepted by the stratigraphic commission of hungary­were­published­in­császár­(1997). 4.1. lithostratigraphic units our­investigations­of­both­surface­and­subsurface­sediments­and­ their­fossil­content­showed­that­formation­boundaries­are­timetransgressive­over­the­entire­drava­basin­and­its­surroundings,­ and­do­not­coincide­with­the­boundaries­of­either­dinocyst­or­mollusc biozones. consequently, in our opinion a correlated lithostratigraphic scheme for the upper miocene – pliocene lacustrine­to­fluvial­succession­should­be­based­on­the­lithological­ and sedimentological – and corresponding seismic – characteristics­of­the­deposits.­here­we­present­the­proposed­lithostratigraphic­scheme­correlated­between­croatia­and­hungary­(fig.­3)­ and the short description of the units. 4.1.1. kálla formation sand,­gravelly­sand­and­gravel,­typically­limonitic,­often­with­ abundant­molds­and­imprints­of­littoral­molluscs­(fig.­4)­(kleb,­ 1973;­sztanó­et­al.,­2010;­sebe­et­al.,­2015).­it­occurs­around­ figure 3. correlation of the upper miocene – pliocene lithostratigraphic units in croatia and hungary. preferred formation names are capitalized, abandoned or local names are in plain format. age limits of the formations come from biostratigraphy discussed below. note that the chart follows the axial sediment transport routes, either in deep basin centres or above sublacustrine highs. marginal areas, which contain more locally-derived clastics and several unconformities, cannot be illustrated in the same figure. g eologia c roatica sebe et al.: correlation of upper miocene-pliocene lake pannon deposits across the drava basin, croatia and hungary 181 the basement highs that emerged as islands from the lake. consequently,­it­is­more­abundant­along­the­margins­of­the­drava­ basin.­its­material­was­derived­from­local­sources,­from­the­denudation of the immediate background, and accumulated on the shoreface or on small locally fed deltas. its thickness ranges from a­few­metres­to­a­few­tens­of­metres.­being­sourced­from­older­ rocks,­it­sometimes­contains­vertebrate­and­subordinately­invertebrate­fossils­redeposited­from­lower­-­middle­miocene­formations­or­even­from­mesozoic­rocks­(kleb,­1973;­sebe­et­al.,­ 2015).­in­most­places­it­is­a­transgressive­deposit­at­the­base­of­ the­lake­pannon­succession,­unconformably­overlying­older­ rocks,­thus­its­age­depends­on­the­time­of­flooding.­at­some­locations­around­the­mecsek­mts.,­where­sediment­input­into­the­ lake­was­high,­it­overlies­offshore­calcareous­marls­and­prinches­ out,­quickly­away­from­the­mountains.­on­palaeohighs­flooded­ at­a­later­stage­it­interfingers­with,­or­it­is­overlain­by­the­újfalu­ formation­(e.g.­budai­et­al.,­2019).­the­mollusc­fauna­of­the­ formation contains littoral forms of dreissenids, cardiids, and prosobranch­snails,­but­the­actual­species­composition­always­ depends­on­the­age­of­the­given­occurrence­(kleb,­1973;­sebe­ et­al.,­2015).­the­best­exposures­in­the­mecsek­are­the­sand­pits­ of­pécs-danitzpuszta­(with­congeria pancici, c. ungulacaprae, c. partschi, lymnocardium schedelianum;­sebe­et­al.,­2015),­ pécsvárad­and­himesháza­(with­congeria balatonica, l. dumi­ cici, l. cf. proximum, „protoplagiodacna” sp., phyllocardium planum;­budai­et­al.,­2019),­and­cserdi­(with­congeria trian­ gularis, lymnocardium ferrugineum, l. pelzelni, l. schmidti, l. szaboi, prosodacnomya dainellii).­for­the­location­of­sites­mentioned­in­the­text,­please­refer­to­supplement­1. 4.1.2. békés conglomerate formation, sveti matej member of croatica formation coarse clastics – conglomerates and breccias – occur in the region in­two­main­forms­at­the­base­of­the­calcareous­marls­(fig.­5).­the­ sediment­is­similar­in­both­cases:­gravel­material­is­of­local­origin,­ while­sorting­and­rounding­is­variable,­depending­on­the­transport­ and­reworking­processes­and­–­in­the­case­of­the­békés­conglomerate­–­on­water­depth,­i.e.­below­or­above­wave­base. the­sveti­matej­member­of­the­croatica­formation­is­composed­of­unfossiliferous­gravel­deposited­unconformably­over­ pre-pannonian­rocks­in­a­fluvial­environment.­it­is­maximum­a­ few­metres­thick­and­is­overlain­by­the­thin-bedded­limestones­ of­the­croatica­fm.­(fig.­5a).­it­is­only­known­in­the­medvednica­ mts.­as­a­fluvial­sediment,­it­represents­temporary­emergence­of­ the­area.­terrestrial­deposits­predating­lacustrine­flooding­in­ hungary­are­classified­into­the­ősi­variegated­clay­fm.,­though­ this­unit­has­not­yet­been­recorded­in­the­mecsek-drava­area. the­békés­conglomerate­(fig.­5b)­comprises­gravels­reworked­by­lacustrine­wave­action­and­is­conformably­overlain­by­ the­calcareous­marls­of­the­endrőd­fm.­typical­grain­size­is­below­10­cm,­but­the­largest­clasts­can­exceed­1­m.­matrix­material­ is­either­missing­or­is­identical­to­the­overlying­marls.­the­unit­ is typically unfossiliferous, its thickness ranges from 1-2 m to ~20­m.­the­wave-reworked­gravels­indicate­the­flooding­of­drylands,­therefore­the­unit­occurs­at­locations­where­open­lacustrine­ sediments­overlie­older­rocks­unconformably:­along­the­margins­ and­in­the­southern­foreland­of­the­mecsek­mts.­above­uplifted­ basement highs. the best outcrops are in the monyoród and versend­quarries. figure 4. kálla formation. a) tectonically tilted coarse, gravelly sands in the pécs-danitzpuszta sand pit; b) limonitic sand with mollusc molds and imprints (lymnocardium in the centre), cserdi, w mecsek mts. figure 5. conglomerates overlying the pre-pannonian sediments or the basement. a) gravels of the sveti matej member in erosional contact with underlying laminated marls of sarmatian dolje formation (sveti matej, medvednica mts.) b) békés conglomerate in the southern foreland of the mecsek mts. (monyoród quarry). g eo lo gi a c ro at ic a geologia croatica 73/3182 4.1.3. endrőd formation, croatica and medvedski breg formations the carbonate-dominated unit at the bottom of the lake pannon succession­is­treated­as­one­formation­in­hungary­and­as­two­in­ croatia. white and grey, thin-bedded limestones and calcareous marls­compose­the­lower­part­of­the­unit,­followed­by­light­greyish,­thick-bedded­to­massive­calcareous­marls,­topped­by­clay­ marls­and­silty­marls­(fig.­6­a-c).­at­locations­close­to­basement­ highs, thin (<1 m thick) clastic intercalations (marl, clay, sand and gravel)­occur­in­the­lower­part­of­the­calcareous­marls.­its­thickness­ranges­from­a­few­tens­of­metres­in­marginal­areas­to­50-200­ m­in­the­centre­of­the­drava­basin­(fig.­7,­e.g.­well­potony-1).­in­ hungary­the­calcareous­marl­(with­>~70%­carbonate­content)­at­ the­lower­part­of­the­endrőd­fm.­is­separated­as­the­tótkomlós­ member in the great hungarian plain and as the belezna mb. to the­west­of­the­danube.­it­can­be­white­near­basement­highs­or­ black­in­the­deep­basin­interiors­(magyar­et­al.,­2004)­and­contains­sufficient­amounts­of­toc­to­be­a­source­rock­(badics­&­ vető,­2012).­the­upper­part­comprising­clay­marls­is­distinguished­as­the­nagykörű­mb.­in­the­great­hungarian­plain­and­ as­the­nagylengyel­mb.­in­the­west­(juhász,­1998),­and­it­occurs­mostly­in­deep­basins.­the­endrőd­fm.­corresponds­to­the­ croatica­and­medvedski­breg­fms.­in­croatia,­which,­based­on­ their lithological composition and stratigraphic position, are further­an­equivalent­of­the­upper­part­of­the­moslavačka­gora­fm.­ (križevci­mb.)­and­the­lower­part­of­the­ivanić-grad­fm.­(lipovac­mb.)­in­the­wdb­and­the­valpovo­fm.­and­of­the­lower­part­ of­ the­vinkovci­fm.­ (laslovo­mb.)­ in­ the­edb­ (fig.­2)­ (eg.­ malvić­&­cvetković,­2013).­the­unit­is­conformably­overfigure 6. a-c: endrőd fm./croatica and medvedski breg fms. a) thin-bedded limestones and calcareous marls with clay interbeds in the lower part of the unit (pécs-danitzpuszta sand pit, mecsek mts.; image width 2 m); b) thin-bedded limestones of the croatica fm. (našice quarry, krndija mts.); c) massive calcareous marls in the upper part of medvedski breg fm. (našice quarry). d-f: andraševec fm./szolnok and algyő fms. d) thinto medium-bedded graded, laminated turbidites alternate with siltstones at mirti/hruševec; e) a graded, structureless to planar and cross-laminated turbidite bed at the lower part of petnja outcrop; f) sandstone with imbricated rip-up mud clasts (well tp-1, 2564-2565 m) g eologia c roatica sebe et al.: correlation of upper miocene-pliocene lake pannon deposits across the drava basin, croatia and hungary 183 lain­by­the­szolnok/andraševec­fm.­in­the­deep­basin­interiors­ or­by­the­algyő/andraševec­fms.­on­sublacustrine­basement­ highs. the­formation­contains­an­impoverished­sublittoral-profundal­mollusc­fauna­with­usually­thin-shelled­forms,­such­as­con­ geria banatica, “dreissenomya” digitifera, “pontalmyra” otiophora,­various­paradacna­species,­and­deep-water-adapted­ pulmonate molluscs, such as planorbids (gyraulus) and lymnaeids (e.g. velutinopsis, undulotheca, valenciennius),­as­well­as­ a rich ostracod assemblage­ (juhász­&­magyar,­ 1992;­ kovačić,­2004;­vasiliev­et­al.,­2007;­magyar­in­sebe­et­al.,­ 2015).­littoral­fossils­occur­in­redeposited­interbeds.­a­diverse­ thermophilous­macroflora­was­recovered­in­the­mecsek­mts.­in­ the­uppermost­part­of­the­formation­(hably­&­sebe,­2016).­ the­general­trend­of­the­unit­from­carbonate-dominated­to­clay/ silt-dominated rocks has been attributed primarily to the increasing amount of clastic input into the lake transported by the distal alpine-carpathian­feeder­system­approaching­the­area­from­the­ n­and­nw.­the­lower­boundary­of­the­formation­coincides­with­ the­sarmatian/pannonian­boundary­in­basins­with­continuous­ sedimentation­across­the­middle/late­miocene­boundary,­while­it­ becomes­increasingly­unconformable­and­thus­younger­away­ from­the­basin­centres.­the­youngest­biozone­identified­in­the­ formation­within­the­drava­basin­is­the­spiniferites validus dinoflagellate­zone (<9­ma;­bakrač­et­al.,­2012­and­fig.­7). the­type­localities­in­croatia­are­the­kostanjek­and­vrapče­ sections­(croatica­fm.)­and­the­medvedski­breg­section­(m.­b.­ fm.)­in­the­nw­part­of­the­sava­basin,­on­the­slopes­of­the­medvednica­mts.­ (kovačić­ et­ al.,­ 2016,­ 2017a;­ kovačić­&­ pavelić,­2017).­at­present­the­most­representative­surface­occurrences­are­the­našice­quarry­on­the­northern­slopes­of­the­ krndija­mts.­(kovačić­et­al.,­2017a)­and­the­pécs-danitzpuszta­ sand­pit­in­the­mecsek­mts.­(sebe­et­al.,­2019). croatica formation the­lower,­well-bedded,­hard,­carbonate-rich,­20–50­m­thick­part­ of­the­endrőd­fm.­occurring­in­the­vicinity­of­basement­highs­is­ distinguished as the croatica fm. in croatia. most commonly it rests­conformably­over­sublittoral­sarmatian­deposits,­rarely­over­ alluvial­sediments­which­unconformably­overlie­different­basement­rocks­(fig­5a).­the­unit­is­identified­by­its­1-10­cm­thick,­ white­calcareous­marl­or­limestone­layers­(fig.­6b).­based­on­ their lithological features, thin-layered limestones of the croatica fm.­in­the­marginal­parts­of­the­basin­are­clearly­different­from­ the­overlying­massive­marls­of­the­medvedski­breg­fm.,­while­ these­differences­are­not­clearly­expressed­in­the­deeper­parts­of­ the­basin,­where­the­calcareous­marls­or­limestones­conformably­ overlying­sarmatian­deposits­are­massive,­dark­grey,­and­represent­source­rocks­(troskot-čorbić­et­al.,­2009).­the­croatica­fm.­is­the­equivalent­of­the­upper­part­of­the­moslavačka­ gora­fm.­(križevci­mb.)­in­the­wdb­and­of­the­valpovo­fm.­in­ the­edb.­it­is­not­equivalent­to­the­tótkomlós­member­within­the­ endrőd­fm.,­but­can­be­correlated­only­with­its­lowermost­part.­ laterally­and­upwards­it­gradually­passes­into­the­marls­of­the­ medvedski­breg­fm.­it­is­widely­distributed­in­the­marginal­parts­ of depressions in the southern part of the pannonian basin system. the­first­description­of­this­unit­under­the­name­„pre-pontian­ formation”­ (gorjanović-kramberger,­1890)­already­ drew­attention­to­its­peculiar­mollusc­fauna,­consisting­of­pulmonate snails (e.g. radix croatica, gyraulus praeponticus, g. du­ bius) and small cardiids (e.g. “lymnocardium” praeponticum). the ostracod assemblage contains brackish species (e.g. herpe­ tocyprella auriculata), while­the­calcareous­nannoplankton­association is rich in the endemic species isolithus semenenko and i. pavelici (ćorić in kovačić­et­al.,­2015,­2017a). the palynological­samples­contain­no­dinoflagellates­but­they­are­rich­in­the­ prasinophyte alga mecsekia ultima (bakrač,­2005).­freshwater algae representing sigmopollis spp.­have­also­been­identified­ in­this­formation­(kovačić­et­al.,­2015),­as­well­as­plant­remains­ (aquatic grasses). the­depositional­environment­of­this­unit­is­usually­interpreted­as­a­stressed,­low-salinity,­shallow-water,­littoral-sublittoral­setting­(vrsaljko,­1999;­kovačić­et­al.,­2017a).­while­ marl­intercalations­are­inferred­to­indicate­water-level­oscillations­ that­temporarily­created­deeper­water,­the­sediments­of­the­croatica­fm.­are­interpreted­to­reflect­lowstand­deposition­as­a­consequence­of­regression­at­the­end­of­the­sarmatian­(pavelić­et­ al.,­2003).­the­arguments­in­favour­of­the­shallow,­littoral-sublittoral­environment­include­the­abundance­of­pulmonate­snails­ (planorbidae­and­lymnaeidae),­which­are­mostly­known­today­ as­shallow-water­or­paludal­dwellers,­the­lack­of­dinoflagellate­ cysts,­the­presence­of­prasinophyte­algae­and­rooted­aquatic­vegetation­(e.g.­vrsaljko,­1999;­vasiliev­et­al.,­2007).­the­overall­position­of­the­croatica­fm.,­lying­unconformably­above­alluvial­sediments­of­the­sveti­matej­mb.­or­different­pre-miocene­ basement­rocks,­or­conformably­overlying­shallow-water­sarmatian­deposits­(vrsaljko,­1999;­kovačić­et­al.,­2015),­also­ suggests­a­relatively­shallow­water­origin. the­typical­fauna­and­algal­flora­of­the­croatica­fm.,­however,­can­often­be­observed­in­lithologically­different­sediments,­ always­representing­the­earliest­pannonian.­in­fact,­this­special­ fossil assemblage is apparently present in much of the pannonian basin­system,­in­places­where­the­sarmatian/pannonian­boundary is characterized by continuous sedimentation. it indicates a specific­environment,­which­was­obviously­widespread­in­the­ earliest­pannonian,­but­did­not­last­very­long,­only­a­few­hundred­ thousand years at most. therefore, this assemblage can be used as­a­biostratigraphic­marker,­upon­which­the­„lymnocardium” praeponticum­zone­(korpás-hódi,­1987),­the­radix croatica – lymnocardium plicataeformis – gyraulus praeponticus cenozone­(vrsaljko,­1999),­the­mecsekia ultima­zone­(sütőszentai,­1982),­and­the­mecsekia ultima – spiniferites bentorii pannonicus­zone­(bakrač­et­al.,­2012)­were­established.­the­ mecsekia ultima and “lymnocardium” praeponticum­zones­have­ also­ been­ reported­ from­ deep-water,­ clay-silt­ deposits­ (e.g.­ ­sztanó­et­al.,­2005;­sütő-szentai­&­szegő,­2008).­generally, the families of lymnaeidae and planorbidae are dominated by­littoral­and­sublittoral­taxa­indeed,­but­in­lake­pannon­some­ of­their­representatives­conquered­the­deep-water­environment­ (juhász­&­magyar,­1992;­geary­et­al.,­2000).­even­within­ the­drava­basin,­such­species­of­gyraulus, velutinopsis and va­ lenciennius­occur­in­core­samples­from­the­bottom­of­several­ hundred­metre­high­shelf-break­slopes­(fig.­13),­indicating­a­very­ deep habitat for these animals. thus, the original habitat of this earliest pannonian peculiar fossil assemblage remains a puzzle. dorozsma marl member of the endrőd formation, bačun member of the medvedski breg formation in­the­vicinity­of­basement­highs,­the­offshore­calcareous­marls­ and­marls­contain­clastic­intercalations­(gravel,­sand,­silt)­originating from the erosion of the emergent blocks. these are classified­under­the­name­bačun­mb.­within­the­croatica­and­medvedski­breg­fms.­in­croatia­and­as­the­dorozsma­mb.­within­the­ g eo lo gi a c ro at ic a geologia croatica 73/3184 fi gu re 7 . c om po si te se is m ic re fle ct io n pr ofi le 1 a lo ng th e ax is o f t he d ra va b as in a nd it s i nt er pr et at io n. f or p ro fil e lo ca tio n se e fi g. 1 . f or d et ai ls o n elo g m ar ke rs u se d in th e hy dr oc ar bo n in du st ry se e vr ba n ac (2 00 2) . t he le ge nd fo r fi rs t oc cu rr en ce s s er ve s b ot h fo r t hi s fi gu re a nd fo r f ig . 8 . s ec tio ns 2 a nd 4 a re sh ow n in f ig . 8 . g eologia c roatica sebe et al.: correlation of upper miocene-pliocene lake pannon deposits across the drava basin, croatia and hungary 185 endrőd­fm.­in­hungary.­the­deep-water­redepositional­character­ of these conglomerates and sandstones by turbidity currents and debris­flows­is­unambiguously­shown­by­their­sedimentary­facies­ in the form of graded beds, complete and incomplete bouma-sequences­and­widespread­pebbly­mudstones­(bérczi­&­phillips,­1985;­bérczi­et­al.,­1987;­sztanó­et­al,­2013b).­in­the­ deep­parts­of­the­se­drava­basin­such­coarse-grained­material­ was­identified­in­wells­(e.g.­sječe-2). 4.1.4. szolnok and algyő formations, andraševec formation deep-water­sandstones­and­shales­are­classified­as­the­andraševec­ fm.­in­croatia­(kovačić,­2004;­kovačić­et­al.,­2004).­the­ same­deposits­are­assigned­to­the­szolnok­and­algyő­fms.­in­ hungary, representing basin-centered turbidite systems, and slope­shales­together­with­the­slope-related­turbidite­systems,­respectively­ (bérczi,­1988;­ juhász,­1994;­sztanó­et­al.,­ 2013b).­these­deep-water­formations­conformably­overlie­the­ endrőd/medvedski­breg­fm.,­and­they­are­conformably­overlain­ by­ the­újfalu/nova­gradiška­fm.­they­are­ the­approximate­ equivalents­of­the­middle­and­upper­parts­of­the­ivanić-grad­fm.­ and­kloštar­ivanić­fm.­in­the­wdb,­and­the­middle­and­upper­ parts­of­vinkovci­fm.­in­the­edb.­ the­szolnok­fm.­and­the­lower­part­of­the­algyő­fm.­consist­ of­very­fine­to­medium-grained­sandstones­intercalated­with­siltstones­(fig.­6­d-f).­the­thickness­of­the­sandstone­beds­varies­ from­a­few­cm­to­several­metres.­thin­sandstone­beds­commonly­ alternate­with­siltstones­a­few­centimetres­in­thickness.­as­the­ thickness of the sandstone beds increases, the frequency and thickness of silty interbeds decrease. cmto dm-thick sandstone beds­commonly­show­sedimentary­structures­including­plane­to­ cross-lamination,­convolution­and­normal­grading.­bouma­sequences­may­occur.­thick­beds­are­usually­structureless­or­show­ faint­water­escape­dishes­or­pipes.­in­the­wells,­10-50­m­thick­ sand-prone­intervals­alternate­with­a­few­tens­of­metres­of­mudprone­intervals.­intervals­of­thick­stacked­sandstones­with­muddy­ intervals­less­­than­a­few­metres­thick,­occur­at­the­upper­part­of­ the sand-prone succession, i.e. in the upper part of the turbidite systems­(tp-1­and­fel-i).­the­thin-bedded­heterolithic­part­of­the­ successions represents the lobe margins of deep lacustrine turbidite­systems,­while­thick-bedded­to­amalgamated­sandstones­ were­deposited­at­the­lobe­axis­and­off-axis­regions­(sztanó­et­ al.,­2013b).­the­clastic­detritus­is­mineralogically­and­structurally­ relatively­mature­ and­had­been­produced­mostly­by­ the­ weathering­of­siliciclastic­sedimentary­and­metamorphic­rocks­ of­alpine­provenance­(kovačić­&­grizelj,­2006). figure 8. composite seismic reflection profiles 2 and 4 from the margin to the centre of the drava basin and their interpretation. for profile locations see fig. 1. for legend see fig. 7. g eo lo gi a c ro at ic a geologia croatica 73/3186 in­the­drava­basin­it­is­difficult­to­distinguish­the­basin-centre and the slope-related turbidite systems, i.e. to determine the boundary­between­the­szolnok­and­algyő­formations.­in­many­ depressions­of­the­pannonian­basin­system,­turbidites­were­deposited­at­several­tens­or­even­more­than­100­km­away­from­the­ feeding­slope,­where­the­source­areas­were­often­separated­from­ the­sink­areas­by­the­rough­relief­of­the­lake­floor­(cf.­sztanó­ et­al.,­2013a,­b).­in­contrast,­“toe-of-slope”­turbidite­systems­of­ the­algyő­formation­accumulated­within­a­distance­of­10-20­km­ from­the­slope­(cf.­sztanó­et­al.,­2013b).­the­latter­are­normally­ more­sensitive­to­interactions­between­lacustrine­base­level­and­ sedimentation­rates,­which­determine­the­aggradation/progradation­rates­of­the­shelf-break­slope.­in­the­drava­basin,­however,­ the source of turbidites can be traced back to a distance of 100 km­(see­the­“8­ma”­horizon­or­galeacysta etrusca­horizon­in­fig.­ 7),­as­most­of­the­system­was­not­influenced­by­confining­basin­ floor­topography,­at­least­not­in­the­nw-se­axial­direction.­therefore,­the­sand/shale­ratio,­or­the­stacking­pattern­of­deep-water­ lobes­might­have­been­controlled­by­these­allocyclic­processes­in­ addition­to­free­autocyclic­lobe­switching.­the­exact­linkage­between­the­aforementioned­processes­needs­further­investigation.­ seismically­the­szolnok­fm.­is­characterized­by­parallel,­low­to­ moderate amplitude, moderate to high continuity seismic facies. in­the­lower­part,­reflections­onlap­apparently­on­the­basement­or­ on­the­1-2­reflections­thick­endrőd­fm.­the­lower­part­of­the­ algyő­fm.­is­seismically­similar,­but­several­downlap­reflections­ occur. the­upper­part­of­the­algyő­fm.­is­composed­of­siltstone­and­ clay­marl­with­rare­and­thin­intercalations­of­sandstone.­mudstones can be structureless or laminated, chaotic beds and slump folds­are­common­(ih-1).­this­part­of­the­algyő­formation­corresponds to the inclined part of the clinoforms. the shelf-edge can­usually­be­identified­relatively­easily­(see­marks­in­figs.­7­ and­8),­where­dipping­reflectors­deviate­from­overlying­parallel­ ones.­the­dip­of­the­clinoforms­gradually­decreases­towards­the­ bottomsets,­but­several­downlaps­help­to­distinguish­the­toe­of­ slope. the height of the clinoforms can be used to estimate palaeo-water­depth­(pogácsás­&­révész,­1987;­balázs­et­ al.,­2018),­which­could­reach­900-1300­m­in­the­centre­of­the­ drava­basin­(kovács­et­al.,­under­review). the thickness of deposits related to the turbidite systems is ~1000­m­at­péterhida­but­exceeds­1300­m­in­the­deepest­part­of­ the­basin­(wells­tp­and­fel).­the­uppermost­300-400­m­is­related­ directly­to­the­toe­of­slope.­on­the­iharosberény­high­(ih-1,­fig.­ 8a)­a­100­m­thick­succession­of­toe-of-slope­turbidites­lies­unconformably on badenian limestones. the thickness of the monotonous­mudstones­(upper­part­of­algyő­fm.)­over­the­basement­ highs­can­be­as­little­as­300­m­(ih),­while­it­attains­500-600­m­in­ the central part of the basin. the­szolnok,­algyő­and­andraševec­formations­contain­a­ profundal­mollusc­fauna­with­congeria banatica, “dreisseno­ mya” digitifera, paradacna abichi, p. lenzi, “pontalmyra” otiophora, valenciennius reussi, accompanied by sublittoral species including c. czjzeki, c. zagrabiensis, c. croatica, and lym­ nocardium majeri­ in­ the­ uppermost­ part­ of­ the­ algyő­ and­ andraševec­formations. in the ostracod assemblage amplocypris reticulata, candona (caspiolla) lobata, c. (pontoniella) paracu­ minata, smooth hemicytheria marginata, cyprideis ex­ gr. macrostigma, cy. obesa, and nodose forms of the genus cypri­ deis dominate,­while­the­dinocyst­assemblage­consists­of­mainly­ endemic forms, such as s. bentorii “coniunctus”, s. virgulaefor­ mis, s. paradoxus, s. balcanicus, s. validus­etc.­the­vertical­arrangement­of­the­facies­within­the­andraševec­fm.­and­the­accompanying­fossil­communities­indicate­the­shallowing­of­the­ depositional­environment. the­ type­ areas­ where­ turbidite­ successions,­ i.e.­ the­ andraševec­fm.­are­exposed­at­the­surface,­are­the­hrvatsko­ zagorje­region­and­the­medvednica­mts.­in­nw­croatia.­the­formation­is­named­after­the­andraševec­sections­on­the­northern­ slopes­of­the­medvednica­mts.­spectacular­outcrops­of­the­turbidite­ system­ exist­ in­ the­ n­medvednica­ (mirti/hruševec;­ kovačić­et­al.,­2004).­the­lower­part­of­the­petnja­sand­pit­in­ the­dilj­mts.­exposes­a­turbidite­lobe­with­channels.­(this­outcrop­was­previously­interpreted­as­a­shallow­delta­and­thus­classified­into­the­nova­gradiška­fm.­(pavelić,­2001;­kovačić­ et­al.,­2017b)).­no­outcrops­of­the­typical­algyő­or­szolnok­fm.­ exist­in­sw­hungary.­sediments­of­a­less­than­100­m­high­slope,­ transitional­in­size­between­shelf­break­and­and­delta­scale­slopes,­ are­exposed­at­the­village­of­szulimán­(sztanó­et­al.,­2015). 4.1.5. újfalu formation, nova gradiška formation the unit consists of an alternation of sand and calcareous silt layers­with­intercalations­of­lignite,­variegated­clay­and­gravel­(fig.­ 9).­the­sediments­display­a­coarsening­upward­trend­on­the­scale­ of­20-50­m­thick­intervals.­the­successions­begin­with­bioturbated­or­laminated­siltstones,­overlain­by­thin-bedded­silt-sand­ heterolithics. slump folds and other soft-sediment deformation structures are common. the sands are structurally and mineralogically­very­similar­to­the­sands­of­the­andraševec­fm.,­indicating a common source area. tabular to trough cross-bedding, symmetrical and asymmetrical cross-lamination, occasionally plane lamination­are­visible­in­the­sandy­units.­erosional­surfaces­are­ occasionally marked by small pebbles, mollusc debris and mud intraclasts.­cross-bedded­sets­may­be­stacked­or­alternate­with­ cross-laminated sands. they mostly originated from the migration­of­dunes­towards­the­se.­rarely­observed­symmetrical­to­ slightly asymmetrical cross-lamination is the result of current and wave­action.­the­calcareous­silts­are­massive,­strongly­bioturbated,­and­locally­contain­relics­of­horizontal­lamination.­alternating­fine-grained­variegated­sediments­with­pedogenic­features,­ organic-rich­ sands-silts,­ gravels­ and­ lignite­ are­ characteristic of the upper part of the cycles and are more frequent in the upper parts of the formation. subsurface data from both­wells­and­seismic­sections­indicate­that­this­unit­attains­a­ thickness­of­1500­m­in­the­nw­drava­basin,­while­it­is­only­ca.­ 300­m­thick­in­the­se­(fig.­7).­the­unit­conformably­overlies­the­ algyő/andraševec­fm.­in­the­hrvatsko­zagorje­region­and­in­the­ db­it­is­overlain­by­the­pluska­fm.,­while­in­the­požega­and­sava­ basins­by­the­vrbova­(cernik)­fm.­(kovačić,­2004;­halamić­ et­al.,­2019).­nova­gradiška­fm.­is­the­approximate­equivalent­of­ the­bilogora­fm.­in­the­wdb­and­the­vera­fm.­in­the­edb. the formation contains a littoral-sublittoral mollusc fauna with­congeria rhomboidea, c. balatonica, c. triangularis, dreissena auricularis, lymnocardium majeri, l. diprosopum, l. arpadense, l. hungaricum, l. rogenhoferi, phyllocardium pla­ num, paradacna okrugici, various prosodacnomya species, etc., as­well­as an­ostracod­assemblage­with hungarocypris pannoni ca and candona (camptocypria) lobata (kovačić,­2004).­the­dinocyst assemblage is dominated by impagidinium globosum, ga­ leacysta etrusca, pyxidinopsis psilata, spiniferites virgulaefor­ mis and spiniferites cruciformis­(bakrač­et­al.,­2012).­the­ sediments­of­the­unit­were­deposited­during­the­late­late­miocene­ and­in­the­eastern­part­of­the­drava­basin­(fig.­7)­during­the­ g eologia c roatica sebe et al.: correlation of upper miocene-pliocene lake pannon deposits across the drava basin, croatia and hungary 187 ­earliest­pliocene,­based­on­the­well­to­seismic­correlation­of­the­ miocene/pliocene­boundary­(fig.­7). the­formation­was­deposited­as­progradational­delta­lobes­ into­the­brackish­lake­pannon­(sztanó­&­magyar,­2007;­ sztanó­et­al.,­2013a),­which­were­strongly­influenced­by­sediment­input­from­the­nw.­the­siltstones­and­the­heterolithics­were­ deposited­on­the­prodelta­to­the­lower­delta­front.­most­of­the­sand­ was­deposited­on­mouth­bars­in­the­upper­delta­front­environment.­sand­deposition­on­the­mouth­bars­was­related­to­prolonged,­frequent­floods­under­humid­climate­conditions.­proximal bar sands continued distally and laterally to distal bar silts affected­by­strong­bioturbation.­short-term­advance,­retreat­and­ lateral shifting of the distributary channels and related mouth bars­resulted­in­the­vertical­alternation­of­proximal­and­distal­ mouth­bar­deposits­(kovačić­et­al.,­2004).­alternating­finegrained­sediments,­sands,­gravels­and­coals­from­the­upper­parts­ of­the­coarsening­upward­units­were­deposited­in­very­shallow­ brackish­interdistributary­bays,­in­brackish­wetlands­or­in­freshwater­marshes­and­ponds­in­a­delta­plain­environment­(juhász­ &­magyar­1992;­juhász,­1994;­kovačić­et­al.,­2004). the­nova­gradiška­formation­is­named­after­sections­located­near­the­town­of­nova­gradiška­in­western­slavonia.­apart­ from­slavonia,­the­type­localities­are­in­the­hrvatsko­zagorje­region­(hum­zabočki­and­selnica­sections)­and­in­the­žumberak­ mt.­(malunje­section).­the­most­representative­surface­occurrence­in­the­drava­basin­is­in­the­našice­quarry­(stevanović,­ 1961).­some­small­occurrences­are­also­detected­in­the­northern­ krndija,­papuk­and­bilogora­mts.­in­hungary­the­újfalu­fm.­is­ usually­exposed­at­some­distance­from­the­basement­outcrops­as­ a­result­of­tilting­and­erosion­caused­by­inversion-related­uplift­ (sztanó­et­al.,­2015,­2016).­the­mozsgó­(fig.­9b)­and­himesháza­ (budai­et­al.,­2019)­sand­pits­exhibit­good­outcrops,­and­the­classic­locality­of­árpád­(now­pécs-nagyárpád;­szónoky­et­al.,­ 1999)­also­belongs­to­this­formation. 4.1.6. zagyva formation, pluska formation the­unit­is­composed­of­alternating­packages­of­a­few­metres,­ occasionally­few­tens­of­metres­thick­cross-bedded,­fining-upward­sands­or­sandstones­and­a­few­metres­to­a­few­tens­of­metres thick successions of silt, clay and possibly lignite or huminitic clay­(fig.­10).­close­to­basement­highs,­gravels­may­also­occur.­ the­clays­are­often­variegated­and­show­signs­of­pedogenesis.­ sands­represent­fluvial­channel­sediments,­the­major­ones­can­be­ visualized­on­seismic­images­(fig.­11),­while­the­silt-clay­units­ can­be­interpreted­as­abandoned­channel-fills­and/or­floodplain­ fines.­though­outcrops­usually­expose­channel­sands,­the­bulk­of­ the­formation­is­composed­of­fine-grained­floodplain­deposits­ (uhrin­&­sztanó,­2007;­nádor­&­sztanó,­2011;­uhrin­ et­al.,­2011;­šujan­et­al.,­2020).­the­thickness­of­the­unit­could­ attain 1000 m in the central depression, e.g. near the borehole ­fel-i­(fig.­7).­in­croatia,­in­the­hrvatsko­zagorje­region,­fluvial­ channel­and­floodplain­sediments­have­been­described­as­the­ pluska­fm.­(kovačić,­2004). figure 9. újfalu fm./nova gradiška fm. a) sand with convolute bedding, silt, huminitic clay and lignite near mučna reka (bilogora hills, croatia); b) medium-grained cross-stratified sand to silt layers and channel forms west of the mecsek mts. (mozsgó sand pit). figure 10. pluska fm. a) erosional contact between well sorted fine-grained sands of the nova gradiška fm. and the overlying poorly sorted gravels, sands and silts of the pluska fm. pluska, hrvatsko zagorje. b) bioturbated, pedogenetically altered sandy silt of the pluska fm. dubravica, hrvatsko zagorje. g eo lo gi a c ro at ic a geologia croatica 73/3188 the­formation­conformably­overlies­sediments­of­the­újfalu/ nova­gradiška­fm.­in­the­basin­centre­and­unconformably­in­ marginal­areas­(figs.­7,­8).­we­do­not­possess­fossil­data­from­the­ formation­which­would­allow­us­to­constrain­the­age­of­the­fluvial­ deposits. based on the interpreted seismic sections of this study, the­formation­started­to­accumulate­in­the­pliocene­(fig.­7).­in­ basinal­areas­it­is­difficult­to­separate­pliocene­fluvial­sediments­ from­their­quaternary­counterparts­(e.g.­nádor­&­sztanó,­ 2011).­the­latter­attain­a­thickness­of­nearly­300­m­in­the­northern­marginal­part­of­the­drava­basin­(e.g.­borehole­görgeteg-i;­ koloszár­et­al.,­2001;­krolopp,­2002),­so­they­can­be­even­ thicker­in­the­basin­centre.­towards­the­basin­margin,­an­unconformity­separates­the­zagyva­fm.­from­the­plio-quaternary­succession,­while­at­the­margins­the­formation­is­often­missing­due­ to pre-quaternary denudation. the dating of the plio-quaternary fluvial­succession­and­thus­the­upper­age­limit­of­the­unconformity­is­uncertain:­based­on­malacostratigraphy,­magnetostratigraphy­and­the­presence­of­a­possibly­volcanogenic­bentonite­layer,­ fluvial­sedimentation­has­been­ongoing­since­at­least­2-2.1­ma,­ but­a­pliocene­age­for­the­lowermost­part­of­the­succession­above­ the­unconformity­cannot­be­excluded­either­(koloszár­et­al.,­ 2001;­krolopp,­2002). 5. biostratigraphic correlations 5.1. dinoflagellates the­dinoflagellate­stratigraphy­of­the­pannonian­stage­(interpreted­ in­ the­ wide­ sense)­ was­ first­ established­ by­ sütőszentai­(1982),­and­it­has­been­continuously­revised­and­improved­ since­ then­ (e.g.­sütő-szentai,­1988,­1990,­2000;­ soliman­&­riding,­2017).­this­system­was­applied­in­croatia­with­some­modifications­(krizmanić­in­lučić­et­al.,­ 2001;­bakrač,­2007;­bakrač­et­al.,­2012). the­dinoflagellate­zones­are­interval­zones­where­subsequent­ zone­boundaries­are­marked­by­the­first­appearance­of­novel­morfigure 11. seismic geomorphology shows a set of minor and major meandering linear elements on time slices extracted from flattened variance attribute 3d data, at a depth of approximately 650 m. these are interpreted as fluvial channels on the alluvial plain building up the zagyva/pluska fm. g eologia c roatica sebe et al.: correlation of upper miocene-pliocene lake pannon deposits across the drava basin, croatia and hungary 189 phologies (species). there is consensus that the oldest pannonian deposits are characterized by spiniferites pannonicus,­and,­where­ present, by the prasinophyte mecsekia ultima,­which­always­occurs­immediately­above­the­sarmatian­sediments.­the­first­appearances of spiniferites oblongus and pontiadinium pecs­ varadense are both suitable for marking subsequent biozone boundaries.­the­following­significant­change­in­the­dinocyst­record­is­benchmarked­with­the­more­or­less­coeval­first­appearance­ of­several­forms,­such­as­spiniferites bentorii coniunctus, s. val­ idus, s. balcanicus, and s. paradoxus.­in­this­interval,­either­one­ (s. validus;­bakrač­et­al.,­2012)­or­two­(s. paradoxus or s. co­ niunctus and s. validus;­sütő-szentai,­1991;­krizmanić in­lučić­et­al.,­2001)­or­three­(s. paradoxus, s. validus, s. tih­ anyensis;­sütő-szentai,­2000)­biozones­are­distinguished.­ the­first­appearance­of­galeacysta etrusca marks the base of a new­biozone,­and­the­subsequent­first­appearance­of­spiniferites cruciformis is considered to be the youngest biostratigraphic marker­in­the­sedimentary­succession­of­lake­pannon­(bakrač­ et­al.,­2012;­fig.­3).­ dinoflagellate­data­were­collected­from­several­wells­in­the­ drava­basin­(fig.­12).­when­depicting­dinoflagellate­data­on­the­ seismic­profiles,­it­is­found­that­the­older­biozones­correspond­to­ relatively­thin­(a­few­tens­of­metres)­sediment­packages,­which­ were­deposited­in­deep­water;­these­cannot­be­correlated­along­ seismic­reflectors­between­the­wells­because­the­uncertainty­of­ the­correlation­and­of­the­time/depth­functions­of­wells­is­usually­ greater­than­the­thickness­of­the­individual­biozones.­the­occurrences of galeacysta etrusca and spiniferites cruciformis,­however,­can­be­correlated­between­the­wells.­these­two­species­were­ recovered­from­only­a­few­hydrocarbon­exploration­wells­(see­table­1)­but­they­were­commonly­discovered­in­shallower­boreholes­ from­around­the­villány­hills­(sütő-szentai,­1994,­2011).­ correlations­show­that­the­deepest­occurrences­of­these­species­ in­individual­wells­are­not­coeval,­i.e.­they­do­not­represent­the­ first­appearance­date­(fad)­of­the­respective­forms­(fig.­7).­the­ stratigraphically deepest occurrence of g. etrusca­was­recorded­ in­the­deep-water­deposits­of­the­potony-1­well,­at­2780­m,­thus­ this­occurrence­approaches­the­best­the­real­fad­of­g. etrusca. the­corresponding­shelf­edge­above­the­slope­is­located­some­65­ km­to­the­nw­of­the­well­along­our­section­1­(figs.­7,­1).­the­oldest occurrence of s. cruciformis,­however,­was­found­in­well­sev1,­at­1370­m­depth,­in­shelf­deposits.­the­coeval­shelf­edge­is­identified­at­about­15­km­to­the­se­along­section­1­(fig.­7). 5.2. molluscs in­the­littoral­deposits­of­lake­pannon,­a­series­of­taxon-range­ zones­(or­rather­lineage­zones)­were­established­on­the­basis­of­ subsequent­new­morphologies­within­the­supposedly­anagenetic­ evolutionary­lineage­that­starts­with­lymnocardium edlaueri and ends­with­prosodacnomya vodopici­(müller­&­magyar,­ 1992;­magyar­et­al.,­1999,­2000;­magyar­&­geary,­2012).­ the­boundary­between­the­lymnocardium decorum and proso­ dacnomya carbonifera­zones,­defined­by­the­first­appearance­of­ the genus prosodacnomya,­could­be­clearly­identified­on­seismic­ profiles­in­the­budafa­area,­immediately­east­of­the­northwesternmost­tip­of­section­1­(fig.­7),­based­on­the­data­provided­by­ barnabás­&­strausz­(1991)­on­the­occurrences­of­l. de­ corum and prosodacnomya­in­this­region.­this­dataset­was­completed­with­scattered­unpublished­information­on­the­presence­of­ these­forms­in­hydrocarbon­exploration­wells­from­the­northern­ side­of­the­drava­basin.­based­on­the­above­data,­we­traced­this­ biozone­boundary­on­seismic­profiles­across­the­entire­study­area­ as­shown­in­figs.­7­and­8.­this­seismic­horizon­turned­out­to­be­ only­very­slightly­older­than­the­oldest­occurrence­of­galeacysta etrusca­in­the­potony-1­well. the­profundal­deposits­of­lake­pannon­were­divided­into­ the older congeria banatica zone, characterized by c. banatica and­various­members­of­the­evolutionary­lineage­from­radix to provalenciennesia, and the younger “dreissenomya” digitifera zone, characterized by “d.” digitifera and valenciennius­(magyar­et­al.,­1999;­magyar­&­geary,­2012;­fig.­3).­in­the­ drava­basin,­both­biozones­are­present.­the­shelf-break­slope,­ however,­belongs­to­the­younger­“d.” digitifera­zone­everywhere­ in­the­drava­basin­(figs.­8,­13).­ 6. geochronology our means to date the thick upper neogene succession of the drava­basin­are­severely­limited.­of­the­relevant­biostratigraphic­ boundaries,­only­the­fad­of­prosodacnomya was­reliably­dated.­ the­earliest­representative­of­this­genus,­p. carbonifera­was­recovered­from­a­sedimentary­inclusion­embedded­into­volcanic­ material­in­the­tihany­peninsula,­lake­balaton­(sztanó­et­al.,­ 2013a).­the­tihany­maar­volcano­is­known­to­have­started­its­activity­7.92±0.22­to­7.96±0.03­ma­ago­(as­assessed­by­k/ar­and­ ar/ar­analyses­by­balogh­&­németh­(2005)­and­wijbrans­et­al.­(2007),­respectively).­therefore,­the­first­appearance datum of prosodacnomya could­be­determined­as­ca.­8­ma­ (fig.­3).­this­interpretation­was­recently­confirmed­by­magnetostratigraphic­investigations­in­central­hungary­(kelder­et­al.,­ 2018;­magyar­et­al.,­2019).­the­fad­of­galeacysta etrusca has­long­been­supposed­to­be­very­close­to­that­of­prosodac­ nomya (magyar­&­geary,­2012),­although­the­two­fossils­ never­occur­in­the­same­layer­due­to­their­originally­highly­different­environmental­requirements­(fig.­3). the­biostratigraphic­boundary­between­the­congeria bana­ tica and “dreissenomya” digitifera­zones­in­the­profundal­zone­ of­lake­pannon­was­tentatively­dated­as­ca.­9.6­ma­(magyar­ et­al.,­1999;­magyar­&­geary,­2012;­fig.­3).­in­the­drava­ basin,­this­boundary­runs­within­the­endrőd­formation;­the­corresponding­shelf-break­slope­is­located­in­nw­hungary­(magyar­et­al.,­2013).­­ an­additional­chronological­tie­point­can­be­the­age­of­the­ significant­unconformity­that­is­observed­within­the­late­neogene­ table 1. first (lowest) recorded occurrences of the dinoflagellate species galeacysta etrusca and spiniferites cruciformis in the drava basin boreholes. galeacysta etrusca well core or cutting two-way-time (ms) measured depth (m) dra-1 cutting 1680 2005 f-1d core 1565 1942 potony-1 cutting 2065 2780 sev-1 cutting 1330 1550 víz-s-1* core 1570 2174 *representing data from víz-s-1, víz-s-2, víz-d-1, and her-d-1 wells, which lie on the same seismic reflector spiniferites cruciformis well core or cutting two-way-time (ms) measured depth (m) dra-1 cutting 1232 1310 potony-1 cutting 1714 2065 sev-1 cutting 1210 1370 g eo lo gi a c ro at ic a geologia croatica 73/3190 figure 12. dinoflagellates from wells in the drava basin. 1 spiniferites pannonicus, dravica-1 well, 2880–2885 m, 2 spiniferites oblongus, dravica-1, 2840–2845 m, 3 pontiadinium pecsvaradensis, dravica-1, 2820–2825 m, 4 spiniferites bentorii coniunctus, dravica-1, 2800–2805 m, 5 spiniferites balcanica, dravica-1, 2695–2700 m, 6 spiniferites validus, dravica-1, 2190–2195 m, 7 galeacysta etrusca, dravica-1, 1300–1310 m, 8 spiniferites cruciformis, dravica-1, 1300–1310 m, 9 spiniferites oblongus, legrad-1j, 2076–2081 m, 10 spiniferites balcanica, legrad-1j, 1659–1665 m, 11 spiniferites bentorii coniunctus, legrad-1j, 1659–1665 m, 12 spiniferites validus, legrad-1j, interval 1659–1665 m, 13 spiniferites pannonicus, potony-1, 3260 m, 14 spiniferites oblongus, potony-1, 3204 m, 15 pontiadinium pecsvaradensis, potony-1, 3174 m, 16 spiniferites bentorii coniunctus, potony-1, 3040 m, 17 galeacysta etrusca, potony-1, 2780 m, 18 achomosphaera andalusiensis, severovci-1, 2750–2760 m, 19 galeacysta etrusca, severovci-1, 480–490 m, 20 spiniferites cruciformis, severovci-1, 920–930 m, 21 spiniferites oblongus, zalata-k-1, 2540 m, 22 pontiadinium pecsvaradensis, zalata-k-1, 2500 m, 23 pontiadinium inequicornutum, zalata-k-1, 2460 m, 24 impagidinium globosum, zalata-k-1, 1980 m, 25 galeacysta etrusca, zalata-k-1, 1640 m. g eologia c roatica sebe et al.: correlation of upper miocene-pliocene lake pannon deposits across the drava basin, croatia and hungary 191 succession­of­the­drava­basin­in­its­northern­margin­(ujszászi­ &­vakarcs,­1993;­sacchi­et­al.,­1998,­1999).­this­unconformity­looks­very­similar­to,­and­seems­to­be­geographically­ connected­with­another­unconformity­in­the­sedimentary­succession of the central pannonian basin system („great hungarian plain”),­where­it­was­magnetostratigraphically­dated­between­4.6­ and­ 6.8­ma­ (magyar­&­ sztanó,­ 2008­ and­ references­ therein).­as­the­vertebrate­fauna­was­miocene­below­and­pliocene­above­the­unconformity­in­several­boreholes,­its­basinward­ conformity­was­considered­to­roughly­correspond­to­the­miocene-pliocene­boundary­(5.3­ma;­magyar­&­sztanó,­2008).­ if­we­tentatively­accept­this­approach,­the­5.3­ma­horizon­can­be­ traced­across­much­of­the­drava­basin­within­the­shelf­deposits,­ whereas­in­the­easternmost­part­of­the­basin­it­crosses­the­shelf­ edge­and­continues­in­the­deep-water­deposits­(fig.­7). 7. conclusions the­sedimentary­infill­of­the­drava­basin­is­composed­of­the­ same suite of sedimentary units both on the hungarian and croatian sides, similarly to other parts of the pannonian basin system:­local­transgressive­coarse­clastics­around­emergent­basement­ highs,­ open-to-deep­water­ calcareous­marls,­ turbidite­ sandstones, slope mudstones, and sand to clay sequences deposited­in­delta­plain­and­alluvial­environments.­these­units­can­be­ well­correlated­across­the­basin. the­comparison­of­the­various­rock­units­in­boreholes­with­ seismic­profiles­evidenced­ that­ the­formation­boundaries­are­ time-transgressive­in­the­drava­basin,­similarly­to­other­studied­ regions of the pannonian basin system. at­present,­dinoflagellate­biostratigraphy­and­seismic­stratigraphy­are­the­only­tools­to­subdivide­and­chronostratigraphically­correlate­the­deep-water­deposits­in­the­drava­basin.­when­ plotting­the­first­(lowest)­occurrences­of­individual­species­against­the­seismic­database,­however,­it­becomes­evident­that­investigations from scattered drill cores and cuttings can easily fail to identify­the­first­appearance­datum­of­any­stratigraphic­marker­ species, therefore special attention is required for the interpretation of biozone boundaries in such boreholes. according­ to­ the­ interpreted­ seismic­network,­ sediment­ transport­directions­in­the­study­area­varied­between­n­to­s­and­ w­to­e.­seismic­correlation­of­the­biochronologically­first­appearance­datum­of­the­bivalve­genus­prosodacnomya from outside the study area suggests that the oldest clinoform surfaces in the­mura­basin­are­more­than­8­ma­old.­the­8­ma­old­shelf­edge­ slope­(dated­by­the­fad­of­prosodacnomya) is located in the northernmost­part­of­the­drava­basin,­between­the­wells­leg-1j­and­ sev-1­in­croatia­and­between­wells­­ib-i­and­víz-é-4­in­hungary.­ the youngest clinoforms detected in the southeasternmost part of­the­drava­basin­are­younger­than­the­–­supposedly­–­miocene– pliocene unconformity, thus they might be pliocene in age. acknowledgement research­was­carried­out­within­the­framework­of­the­hungariancroatian bilateral project „stratigraphy and correlation of upper miocene – pliocene sediments along the croatian-hungarian border”­ (tét_16-1-2016-0004),­ and­was­ also­ supported­ by­ the­ otka/nkfih­(hungarian­national­research,­development­ and­innovation­office)­projects­pd104937­and­116618,­by­the­croatian­science­fundation­under­the­project­ip-2019-04-7042,­and­ by­the­bolyai­pd­fellowship­of­the­hungarian­academy­of­sciences­for­ks.­core­inspection­of­some­major­wells­was­financed­ by­the­higher­education­institutional­excellence­programme­of­ the­ministry­of­human­capacities­in­hungary,­within­the­framework­of­the­3rd­thematic­programme­of­the­university­of­pécs.­ donation­of­the­academic­license­of­schlumberger­petrel­software,­and­data­usage­permission­assigned­by­croatian­hydrocarbon­agency­and­ministry­of­economy,­entrepreneurship­and­ crafts­for­phd­research­(mš)­interconnected­to­this­scientific­ project­is­highly­appreciated.­the­aforementioned­phd­research­ was­also­supported­by­intergovernmental­scholarships­of­ the­ hungarian­tempus­public­foundation,­part­of­these­results­are­ incorporated into this article. mol hungarian oil and gas plc. and­ina-industrija­nafte­d.d.­are­acknowledged­for­their­permission­to­use­seismic­and­borehole­data­for­our­study.­this­is­mtamtm-elte­paleo­contribution­no­328.­we­are­grateful­to­oleg­ mandic­and­an­anonymous­reviewer­for­their­thorough­reviews,­which­greatly­improved­the­manuscript. references badics,­b.­&­vető,­i.­(2012):­source­rocks­and­petroleum­systems­in­the­hungarian­ part­of­the­pannonian­basin:­the­potential­for­shale­gas­and­shale­oil­plays.–­marine­and­petroleum­geology,­31,­53–69.­doi:­10.1016/j.marpetgeo.2011.08.015 basch,­o.­(2009):­klastiti­i­ugljen­(pont­–­m7)­[clastites and coal (pontian – m7) –­in­croatian].–­in:­velić,­i.­&­vlahović,­i.­(eds.):­tumač­geološke­karte­ republike­hrvatske­1:300.000­[explanatory note of the basic geological map of the republic of croatia 1:300000­–­in­croatian].­croatian­geological­survey,­ zagreb,­141­p.­ figure 13. “dreissenomya” digitifera and valenciennius reussi from the víz-s-1 well, 2060 m md. the sample is from the bottom part of the algyő formation (see fig. 8), which belongs here to the galeacysta etrusca biozone. the presently 500 m thickness of the algyő clinoforms in this part of the basin indicates that these benthic animals lived in the profundal zone of lake pannon, at a water depth of 700-900 m (for clinoform decompactions see balázs et al., 2018). g eo lo gi a c ro at ic a geologia croatica 73/3192 bakrač,­k.­(2005):­palinološka­karakterizacija­naslaga­srednjeg­i­gornjeg­miocena­jugozapadnog­dijela­panonskog­bazena­[palynology of the middle and upper miocene deposits from the south-western parts of the pannonian basin­–­in­croatian­with­ english­summary].–­unpubl.­phd­thesis,­university­of­zagreb,­173­p. bakrač,­k.­(2007):­middle­and­upper­miocene­palynology­from­the­south-western­ parts­of­the­pannonian­basin.–­joannea­geologie­und­paläontologie,­9,­11–13. bakrač,­k.,­koch,­g.­&­sremac,­j.­(2012):­middle­and­late­miocene­palynological­biozonation­of­the­south-western­part­of­central­paratethys­(croatia).–­geologia­ croatica,­65/2,­207–222.­doi:­10.4154/gc.2012.12 balázs,­a.,­matenco,­l.,­magyar,­i.,­horváth,­f.­&­cloetingh,­s.­(2016):­ the­link­between­tectonics­and­sedimentation­in­back-arc­basins:­new­genetic­constraints­from­the­analysis­of­the­pannonian­basin.–­tectonics,­35,­1526–1559.­­doi:­ 10.1002/2015tc004109 balázs,­a.,­magyar,­i.,­matenco,­l.,­sztanó,­o.,­tőkés,­l.­&­horváth,­ f.­(2018):­morphology­of­a­large­paleo-lake:­analysis­of­compaction­in­the­miocene-quaternary­pannonian­basin.–­global­and­planetary­change,­171,­134–147.­ doi:­10.1016/j.gloplacha.2017.10.012 balogh,­k.­&­németh,­k.­(2005):­evidence­for­the­neogene­small-volume­intracontinental­volcanism­in­western­hungary:­k/ar­geochronology­of­the­tihany­maar­ volcanic­complex.–­geologica­carpathica,­56,­91–99. barnabás,­k.­&­strausz,­l.­(1991):­a­délnyugat-dunántúli­pannonikum­[the pan­ nonian in sw transdanubia –­in­hungarian].–­földtani­közlöny,­119,­191–306. bérczi,­i.­(1988):­preliminary­sedimentological­investigation­of­a­neogene­depression­ in­the­great­hungarian­plain.–­in:­royden,­l.h.­&­horváth,­f.­(eds.):­the­ pannonian­basin.­aapg­memoir,­45,­107–116. bérczi,­i.­&­phillips,­r.l.­(1985):­process­and­depositional­environments­within­ neogene deltaic-lacustrine sediments, pannonian basin, southeast hungary.– geophysical­transactions,­31,­55–74. bérczi,­i.,­dank,­v.,­gajdos,­i.,­pap,­s.,­révész,­i.,­szentgyörgyi,­k.­&­ völgyi,­l.­(1987):­ablagerungen­der­kunság-stufe­(pannonien­s.­str.)­auf­der­ grossen­ungarischen­tiefebene.–­in:­jámbor,­á.­(ed.):­geologische­charakterisierung­der­ablagerungen­der­kunság-stufe­in­ungarn.–­annals­of­the­hungarian­ geological­institute,­69,­179–198. budai,­s.,­sebe,­k.,­nagy,­g.,­magyar,­i.­&­sztanó,­o.­(2019):­interplay­of­ sediment­supply­and­lake-level­changes­on­the­margin­of­an­intrabasinal­basement­ high in the late miocene lake pannon (mecsek mts., hungary).– international journal­of­earth­sciences,­108,­2001–2019,­doi:­10.1007/s00531-019-01745-3 chikán,­g.­(1991):­die­känozoischen­ablagerungen­des­westlichen­mecsekgebirges.–­ annals­of­the­geological­institute­of­hungary,­lxxii,­budapest,­281­p. császár,­g.­(ed.)­(1997):­basic­litostratigraphic­units­of­hungary.–­geological­institute­of­hungary,­budapest,­114­p. csillag,­g.­&­sztanó,­o.­(2015a):­upper­miocene.–­in:­kercsmár,­zs.­(ed.),­ budai,­t.,­csillag,­g.,­selmeczi,­i.­&­sztanó,­o.:­surface­geology­of­ hungary.­explanatory­notes­to­the­geological­map­of­hungary­(1:500­000).­geological­and­geophysical­institute­of­hungary,­budapest,­45–50. csillag,­g.­&­sztanó,­o.­(2015b):­miocene–pliocene.–­in:­kercsmár,­zs.­(ed.),­ budai,­t.,­csillag,­g.,­selmeczi,­i.­&­sztanó,­o.:­surface­geology­of­ hungary.­explanatory­notes­to­the­geological­map­of­hungary­(1:500­000).­geological and geophysical institute of hungary, budapest, 50–51. csontos,­l.,­benkovics,­l.,­bergerat,­f.,­mansy,­j-l.­&­wórum,­g.­(2002):­ tertiary deformation history from seismic section study and fault analysis in a former­european­tethyan­margin­(the­mecsek–villány­area,­sw­hungary).–­tectonophysics,­357/1–4,­81–102.­doi:­10.1016/s0040-1951(02)00363-3 croatian­geological­survey­(2009):­geološka­karta­republike­hrvatske­m­ 1:300.000­[basic geological map of the republic of croatia 1:300000 – in croatian].–­croatian­geological­survey,­department­of­geology,­zagreb. dezső,­j.,­raucsik,­b.­&­viczián,­i.­(2007):­villányi-hegységi­karsztos­hasadékkitöltések­szemcseösszetételi­és­ásványtani­vizsgálata­[granulometric and miner­ alogical analysis of karstic fissure filling sediments in the villány mts. (s hungary) –­in­hungarian].–­acta­ggm­debrecina,­2,­151–180. filjak,­r.,­pikija,­m.,­avanić,­r.,­bakrač,­k.­&­miknić,­m.,­pavelić,­d.,­ brkić,­m.­&­belak,­m.­(2016a):­osnovna­geološka­karta­republike­hrvatske­ mjerila­1­:­50­000,­list­slavonska­požega­3­[basic geological map of the republic of croatia 1:50000, slavonska požega 3 sheet – in croatian].– croatian geological­survey,­department­of­geology,­zagreb. filjak,­r.,­pikija,­m.,­avanić,­r.,­bakrač,­k.­&­miknić,­m.­(2016b):­osnovna­ geološka­karta­republike­hrvatske­mjerila­1­:­50­000,­list­slavonska­požega­4­[ba­ sic geological map of the republic of croatia 1:50000, slavonska požega 4 sheet –­in­croatian].–­croatian­geological­survey,­department­of­geology,­zagreb. geary,­d.h.,­magyar,­i.­&­müller,­p.­(2000):­ancient­lake­pannon­and­its­endemic­molluscan­fauna­(central­europe;­mio-pliocene).–­in:­rossiter,­a.­&­ kawanabe,­h.­(eds.),­ancient­lakes:­biodiversity,­ecology,­and­evolution.­advances­in­ecological­research,­3,­463–482.­doi:­10.1016/s0065-2504(00)31025-x gorjanović-kramberger,­d.­(1890):­die­praepontischen­bildungen­des­agramer­gebirges.–­glasn.­hrv.­narv.­društva,­5,­151–164. hably,­l.­&­sebe,­k.­(2016):­a­late­miocene­thermophilous­flora­from­pécs-danitzpuszta,­mecsek­mts.,­hungary.­neues­jahrbuch­für­geologie­und­paläontologie,­ 279/3,­261–271.­doi:­10.1127/njgpa/2016/0554 halamić,­j.,­belak,­m.,­pavelić,­d.,­avanić,­r.,­filjak,­r.,­šparica,­m.,­ brkić,­m.,­kovačić,­m.,­vrsaljko,­d.,­banak,­a.­&­crnko,­j.­(2019):­ osnovna­geološka­karta­republike­hrvatske­mjerila­1­:­50­000­-­požeška­gora­[ba­ sic geological map of the republic of croatia 1:50000 požeška gora – in croatian].–­croatian­geological­survey,­department­of­geology,­zagreb. hámor,­g.­(1970):­das­miozän­des­östlichen­mecsek-gebirges.–­annals­of­the­geological­institute­of­hungary,­53/1,­371­p. hećimović,­i.,­marsi,­i.,­banak,­a.,­chikán­g.,­ferić,­p.,­grizelj,­a.,­horvat,­m.,­koloszár,­l.­&­magyari,­á.­(2010):­correlation­of­quaternary­and­ tertiary­sediments­of­drava-valley­at­sellye–slatina­sheet,­scale­1:100­000.–­in:­ 4th­croatian­geological­congress,­sibenik,­14-15.­10.­2010.­abstract­book.­croatian­geological­survey,­zagreb,­369–370. hilgen,­f­j.,­lourens,­l.j.,­van­dam,­j.a.,­beu,­a.g.,­boyes,­a.f.,­cooper,­ r.a.,­krijgsman,­w.,­ogg,­j.g.,­piller,­w.e.­&­wilson,­d.s.­(2012):­the­ neogene­period.–­in:­gradstein,­f.­m.,­ogg,­j.g.,­schmitz,­m.­&­ogg,­ g.­(eds.):­the­geologic­time­scale.­elsevier,­923–978.­doi:­10.1016/b978-0-44459425-9.00029-9 horváth,­f.,­bada,­g.,­szafián,­p.,­tari,­g.,­ádám­a.­&­cloething,­s.­ (2006):­formation­and­deformation­of­the­pannonian­basin:­constraints­from­observational­data.–­in:­gee,­d.g.­&­stephenson,­r.a.­(eds):­european­lithosphere­dynamics,­geological­society,­london,­memoirs,­32,­191–206.­ ­doi:­ 10.1144/gsl.mem.2006.032.01.11 horváth,­f.,­pap,­n.,­reményi,­p.­&­tóth,­t.­(2012):­geothermal­resource­assessment­of­the­drava­basin.­idresearch­kft.­/­publikon­publishers,­pécs,­222­p.­ https://secco2.eu/sites/default/files/digital_library/2018-10/lbdb-geothermalresourceassessmentofthedravabasin.pdf horváth,­f.,­dulić,­i.,­vranković,­a.,­koroknai,­b.,­tóth­t.,­wórum,­ g.­&­kovács,­g.­(2018):­overview­of­geologic­evolution­and­hydrocarbon­generation­of­the­pannonian­basin.–­interpretation,­february­2018,­sb111–122.­doi:­ 10.1190/int-2017-0100.1 jenko,­k.­(1944).­stratigrafski­i­tektonski­snošaj­pliocena­južnog­pobočja­požeške­gore­ i­kasonje­brda.–­vjestnik­hrvatskog­državnog­geoložkog­zavoda­i­hrvatskog­ državnog­geoložkog­muzeja,­2/3,­89–159. juhász,­gy.­(1994):­comparison­of­the­sedimentary­sequences­in­late­neogene­subbasins­in­the­pannonian­basin,­hungary.–­földtani­közlöny,­124,­341–365. juhász,­ gy.­ (1998):­ a­ magyarországi­ neogén­ mélymedencék­ pannóniai­ képződményeinek­litosztratigráfiája.­[lithostratigraphy of pannonian formations of neogene deep basins in hungary­-­in­hungarian].–­in:­bérczi,­i.­&­jámbor,­ á.­(eds.):­magyarország­képződményeinek­rétegtana­[stratigraphy­of­geological­ formations­of­hungary].­mol­rt.­– geological institute of hungary, budapest, 469–484. juhász,­gy.­&­magyar,­i.­(1992):­review­and­correlation­of­the­late­neogene­(pannonian s.l.) lithofacies and mollusc biofacies in the great plain, eastern hungary.– földtani­közlöny,­122,­167–194. kelder,­n.a.,­sant,­k.,­dekkers,­m.­j.,­magyar­i.,­van­dijk,­g.a.,­lathouwers,­y.z.,­sztanó,­o.­&­krijgsman,­w.­(2018):­paleomagnetism­in­lake­ pannon:­problems,­pitfalls,­and­progress­in­using­iron­sulfides­for­magnetostratigraphy.–­ geochemistry,­ geophysics,­ geosystems,­ 19,­ 3405–3429.­ doi:­ 10.1029/2018gc007673 kleb,­b.­(1973):­geologie­des­pannons­im­mecsek.–­annals­of­the­geological­institute­ of­hungary,­liii/3,­750–943. koloszár,­l.,­lantos,­m.­&­chikán,­g.­(2001):­a­görgeteg­g–1­és­az­udvari­u– 2a­fúrások­fúrások­negyedidőszaki­képződményeinek­párhuzamosítása­[correla­ tion of the quaternary sediments in the görgeteg g–1 and the udvari u2a bore­ holes­-­in­hungarian].–­földtani­közlöny,­131/3–4,­443–460. konrád,­gy.­&­sebe,­k.­(2010):­new­records­of­young­tectonic­phenomena­in­the­ western­mecsek­mts.­and­their­surroundings.–­földtani­közlöny,­140/2,­445–468. kőrössy,­l.­(1989):­a­dráva-medencei­kőolaj-­és­földgázkutatás­földtani­eredményei­ [hydrocarbon geology of the drava basin in hungary­–­in­hungarian].–­általános­ földtani­szemle,­24,­3–121. korpás-hódi,­m.­(1987):­korrelationsmöglichkeit­der­jungen­neogenbildungen­ungarns.–­annals­of­the­geological­institute­of­hungary,­69,­435–452. korpásné­hódi,­m.­(1998):­medenceperemi­pannóniai­s.l.­üledékes­formációk­rétegtana­[stratigraphy of pannonian s.l. sedimentary formations of the basin margins –­ in­ hungarian].–­ in:­ bérczi,­ i.­ &­ jámbor,­ á.­ (eds.):­ magyarország­ képződményeinek­rétegtana­[stratigraphy of geological formations of hungary]. mol­rt.–­geological­institute­of­hungary,­budapest,­453–468. kovačić,­m.­(2004):­sedimentologija­gornjomiocenskih­naslaga­jugozapadnog­dijela­ panonskog­bazena­[sedimentology of the upper miocene deposits from the south­ western part of pannonian basin­−­in­croatian­with­an­english­summary].−­unpubl.­phd.­thesis,­university­of­zagreb,­203­p. g eologia c roatica sebe et al.: correlation of upper miocene-pliocene lake pannon deposits across the drava basin, croatia and hungary 193 kovačić,­m.­&­grizelj,­a.­(2006):­provenance­of­the­upper­miocene­clastic­material­in­the­southwestern­part­of­the­pannonian­basin.–­geologica­carpathica,­57/6,­ 495–510. kovačić,­m.­&­pavelić,­d.­(2017):­neogene­stratigraphy­of­the­slavonian­mountains.–­in:­kovačić,­m.,­wacha,­l.­&­horvat,­m.­(eds):­7th­international­ workshop­neogene­of­central­and­south-eastern­europe,­28–31­5.­2017.­field­trip­ guidebook,­croatian­geological­society,­zagreb,­5–9. kovačić,­m.,­zupanič,­j.,­babić,­lj.,­vrsaljko,­d.,­miknić,­m.,­bakrač,­ k.,­hečimović,­i.,­avanić,­r.­&­brkić,­m.­(2004):­lacustrine­basin­to­delta­ evolution­in­the­zagorje­basin,­a­pannonian­sub-basin­(late­miocene:­pontian,­nw­ croatia).–­facies,­50/1,­19–33. kovačić,­m.,­horvat,­m.,­pikija,­m.­&­slovenec,­d.­(2011):­composition­and­ provenance­of­neogene­sedimentary­rocks­of­dilj­gora­mt.­(south­pannonian­basin,­croatia).–­geologia­croatica,­64/2,­121–132.­doi:­10.4154/gc.2011.10 kovačić,­m.,­ćorić,­s.,­marković,­f.,­pezelj,­đ.,­bakrač,­k.,­hajek-tadesse,­v.,­vrsaljko,­d.,­bošnjak­makovec,­m.,­kampić,­š.,­ritossa,­a.­&­bortek,­ž:­(2015):­granica­srednjeg­i­gornjeg­miocena­(sarmat/panon)­ u­središnjem­paratetisu­(lokalitet­vranović,­slavonija)­(the­middle/upper­miocene­ (sarmatian/pannonian)­boundary­in­central­paratethys­(vranović­locality,­slavonija).–­in:­horvat,­m.­&­wacha,­l.­(eds.):­abstract­book.­5th­croatian­geological­congress­with­international­participation,­osijek­23.–25.09.2015.­croatian­geological­survey,­136-137. kovačić,­m.,­mandic,­o.­&­tomljenovic,­b.­(2016):­miocene­paleo-lakes­of­ the­southwestern­pannonian­basin.–­in:­mandic,­o.,­pavelić,­d.,­kovačić,­ m.,­sant,­k.,­andric,­n.­&­hrvatović,­h.­(eds):­field­trip­guidebook.­lake­ -­basin­-­evolution,­rcmns­interim­colloquium­2016­&­croatian­geological­society­limnogeology­workshop,­zagreb­(croatian­geological­society),­11–31. kovačić,­m.,­marković,­f.,­ćorić,­s.,­pezelj,­đ.,­vrsaljko,­d.,­bakrač,­ k.,­hajek-tadesse,­v.,­ritossa,­a.­&­tarnaj,­i.­(2017a):­stop­4­vranović.­ disintegration­of­ the­central­paratethys­and­origin­of­ the­lake­pannon.–­ in:­ kovačić,­m.,­wacha,­l.­&­horvat,­m.­(eds.):­neogene­of­the­paratethyan­ region.­7th­international­workshop­on­the­neogene­from­the­central­and­southeastern­europe.­rcmns­interim­colloquium.­field­trip­guidebook. croatian geological­society,­zagreb,­22–25. kovačić,­m.,­mandic,­o.,­horvat,­m.­&­kurečić,­t.­(2017b):­stop­6­petnja.­ the­termination­of­lake­pannon­and­the­origin­of­lake­slavonija.–­in:­kovačić,­ m.,­wacha,­l.­&­horvat,­m.­(eds.):­neogene­of­the­paratethyan­region.­7th­ international workshop on the neogene from the central and south-eastern europe. rcmns­interim­colloquium.­field­trip­guidebook.­croatian­geological­society,­ zagreb,­pp.­22–25. kovács,­á.,­balázs,­a.,­špelić,­m.,­sztanó,­o.­(under­review):­forced­or­normal­regression­signals­in­a­lacustrine­basin?­insights­from­3d­stratigraphic­forward­ modelling in the sw pannonian basin.– global and planetary change. krolopp,­e.­(2002):­alsó-pleisztocén­mollusca-fauna­a­görgeteg-i­fúrásból­[lower pleistocene mollusc fauna from the borehole görgeteg-i (sw hungary) in hungarian].–­földtani­közlöny,­132/1,­89–94. lučić,­d.,­saftić,­b.,­krizmanić,­k.,­prelogović,­e.,­britvić,­v.,­mesić,­ i.­&­tadej,­j.­(2001):­the­neogene­evolution­and­hydrocarbon­potential­of­the­ pannonian­basin­in­croatia.–­marine­and­petroleum­geology,­18,­133–147.­doi:­ 10.1016/s0264-8172(00)00038-6 magyar,­i.­(2004):­tanulságok­a­hazai­pannóniai­puhatestű-rétegtan­történetéből­[what lesson can we learn from the hundred­year history of the lake pannon mollusc bio­ stratigraphy in hungary­–­in­hungarian].–­földtani­közlöny,­134/3,­369–390. magyar,­i.­&­geary,­d.h.­(2012):­biostratigraphy­in­a­late­neogene­caspian-type­ lacustrine­basin:­lake­pannon,­hungary.–­in:­baganz,­o.v.,­bartov,­y.,­ bohács,­k.­&­nummedal,­d.­(eds.):­lacustrine­sandstone­reservoirs­and­hydrocarbon­systems.­aapg­memoir­95,­255–264.­doi:­10.1306/13291392m953142 magyar,­i.­&­sztanó,­o.­(2008):­is­there­a­messinian­unconformity­in­the­central­ paratethys?­–­stratigraphy,­5,­247–257. magyar,­i.,­geary,­d.h.,­sütő-szentai,­m.,­lantos,­m.­&­müller,­p.­ (1999):­integrated­biostratigraphic,­magnetostratigraphic­and­chronostratigraphic­ correlations­of­the­late­miocene­lake­pannon­deposits.–­acta­geologica­hungarica,­42,­5–31. magyar,­i.,­müller,­p.,­geary,­d.h.,­sanders,­h.c.­&­tari,­g.c.­(2000):­ diachronous­deposits­of­lake­pannon­in­the­kisalföld­basin­reflect­basin­and­mollusc­evolution.–­abhandlungen­der­geologischen­bundesanstalt,­56,­669–678. magyar,­i.,­juhász,­gy.,­szuromi-korecz,­a.­&­sütő-szentai,­m.­(2004):­ a­pannóniai­tótkomlósi­mészmárga­tagozat­kifejlődése­és­kora­a­battonya-pusztaföldvári-hátság­környezetében­[the tótkomlós calcareous marl member of the lake pannon sedimentary sequence in the battonya-pusztaföldvár region, se hun­ gary – in hungarian].– földtani­közlöny,­133,­521–540. magyar,­i.,­radivojević,­d.,­sztanó­o.,­synak,­r.,­ujszászi,­k.­&­pócsik,­m.­(2013):­progradation­of­the­paleo-danube­shelf­margin­across­the­pannonian basin during the late miocene and early pliocene.– global and planetary change,­103,­168–173.­doi:­10.1016/j.gloplacha.2012.06.007 magyar,­i.,­sztanó,­o.,­sebe,­k.,­katona,­t.l.,­csoma,­v.,­görög,­á.,­ tóth,­e.,­szuromi-korecz,­a.,­šujan,­m.,­braucher­r.,­ruszkiczay-rüdiger­zs.,­koroknai­b.,­wórum­g.,­sant,­k.,­kelder,­n.­&­ krijgsman,­w.­(2019):­towards­a­high-resolution­chronostratigraphy­and­geochronology­for­the­pannonian­stage:­significance­of­the­paks­cores­(central­pannonian­ basin).–­ földtani­ közlöny,­ 149,­ 351–370.­ doi:­ 10.23928/foldt.kozl.2019.149.4.351 malvić,­t.­&­cvetković,­m.­(2013):­lithostratigraphic­units­in­the­drava­depression­(croatian­and­hungarian­parts)­–­a­correlation.–­nafta,­64/1,­27–33. mandic,­o.,­kurečić,­t.,­neubauer,­t.a.­&­harzhauser,­m.­(2015):­stratigraphic­and­palaeogeographic­significance­of­lacustrine­molluscs­from­the­pliocene­ viviparus beds in­central­croatia.–­geologia­croatica,­68/3,­179–207.­doi:­10.4154/ gc.2015.15 müller,­p.­&­magyar,­i.­(1992):­continuous­record­of­the­evolution­of­lacustrine­ cardiid­bivalves­in­the­late­miocene­pannonian­lake.–­acta­palaeontologica­polonica,­36,­353–372. murphy,­a.­&­salvador,­a.­(1999):­international­stratigraphic­guide­–­an­abridged­ version.–­episodes,­22/4,­255–271. nádor,­a.­&­sztanó,­o.­(2011):­lateral­and­vertical­variability­of­channel­belt­stacking­density­as­a­function­of­subsidence­and­sediment­supply:­field­evidence­from­ the­intramountaine­körös­basin,­hungary.– sepm­special­publication,­97,­375– 392.­doi:­10.2110/sepmsp.097.375 nagymarosy,­a.­&­hámor,­g.­(2012):­genesis­and­evolution­of­the­pannonian­ basin.­in:­haas­j.­(ed.):­geology­of­hungary.–­springer,­heidelberg,­149–198.­ doi:­10.1007/978-3-642-21910-8 pavelić,­d.­(2001):­tectonostratigraphic­model­for­the­north­croatian­and­north­bosnian­sector­of­the­miocene­pannonian­basin­system.–­basin­research,­12,­359–376.­ doi:­10.1046/j.0950-091x.2001.00155.x pavelić,­d.­&­kovačić,­m.­(2018):­sedimentology­and­stratigraphy­of­the­neogene­ rift-type­north­croatian­basin­(pannonian­basin­system,­croatia):­a­review.– marine­and­petroleum­geology,­91,­455-469.­doi:­10.1016/j.marpetgeo.2018.01.026 pavelić,­d.,­kovačić,­m.,­miknić,­m.,­avanić,­r.,­vrsaljko,­d.,­bakrač,­ k.,­tišljar,­j.­galović,­i.­&­bortek,­ž.­(2003):­the­evolution­of­the­miocene­environments­in­the­slavonian­mts.­area­(northern­croatia).–­in:­vlahović,­ i.­&­tišljar,­j.­(eds.):­evolution­of­depositional­environments­from­the­paleozoic­to­the­quaternary­in­the­karst­dinarides­and­the­pannonian­basin.­field­trip­ guidebook,­22,­ias,­173–181. pigott,­j.d.­&­radivojević,­d.­(2010):­seismic­stratigraphy­based­chronostratigraphy­(ssbc)­of­the­serbian­banat­region­of­the­pannonian­basin.–­central­european­journal­of­geosciences,­2/4,­481–500.­doi:­10.2478/v10085-010-0027-2 pikija,­m.­(2009):­vapnenačko-klastične­naslage­(sarmat,­panon­–­m5,6)­[limestone – clastic deposits (sarmatian, pannonian –­m5,6)­–­in­croatian].–­in:­velić,­i.­&­ vlahović,­i.­(eds.):­tumač­geološke­karte­republike­hrvatske­1:300.000­[ex­ planatory note of the basic geological map of the republic of croatia 1:300000 –­in­croatian].­croatian­geological­survey,­zagreb,­141­p. pogácsás,­gy.­&­révész,­i.­(1987):­seismic­stratigraphic­and­sedimentological­ analysis­of­neogene­delta­features­in­the­pannonian­basin.–­annals­of­the­geological­institute­of­hungary,­70,­267–273. prelogović,­e.,­saftić,­b.,­kuk,­v.,­velić,­j.,­dragaš,­m.­&­lučić,­d.­ (1998):­tectonic­activity­in­the­croatian­part­of­the­pannonian­basin.–­tectonophysics,­297,­283–293.­doi:­10.1016/s0040-1951(98)00173-5 rakusz,­gy.­&­strausz,­l.­(1953):­a­villányi-hegység­földtana­[geology of the villány hills­­-­in­hungarian].–­annals­of­the­geological­institute­of­hungary,­41/2,­ 27­p. rögl,­f.­(1996):­stratigraphic­correlation­of­the­paratethys­oligocene­and­miocene.–­ mitt.­gesell.­geol.­bergbaustud.­österr.,­41,­65–73­. sacchi,­m.,­tonielli,­r.,­cserny,­t.,­dövényi,­p.,­horváth,­f.,­magyari,­ o.,­mcgee,­t.m.­&­mirabile,­l.­(1998):­seismic­stratigraphy­of­the­late­miocene­sequence­beneath­lake­balaton,­pannonian­basin,­hungary.–­acta­geologica­hungarica,­41,­63–88. sacchi,­m.,­horváth,­f.­&­magyari,­o.­(1999):­role­of­unconformity-bounded­ units­in­the­stratigraphy­of­the­continental­record:­a­case­study­from­the­late­miocene­of­the­western­pannonian­basin,­hungary.–­in:­durand,­b.,­jolivet,­l.,­ horváth,­f.­&­séranne,­m.­(eds.):­the­mediterranean­basins:­tertiary­extension­within­the­alpine­orogen.­geological­society,­london,­special­publications,­ 156,­357–390.­doi:­10.1144/gsl.sp.1999.156.01.17 saftić,­b.,­velić,­j.,­sztanó,­o.,­juhász,­gy.­&­ivković,­z.­(2003):­tertiary­ subsurface­facies,­source­rocks­and­hydrocarbon­reservoirs­in­the­sw­part­of­ the pannonian basin (northern croatia and south-western hungary).– geologia croatica,­56,­101–122.­ sebe,­k.,­konrád,­gy.­&­magyar,­i.­(2013):­a­legmagasabban­fekvő­mecseki­ pannon-tavi­üledékek­helyzete­és­kora­[on the position and age of the highest­lying lake pannon deposits in the mecsek mts (sw hungary) – in hungarian].– földtani­közlöny,­143/1,­445–468. sebe,­k.,­csillag,­g.,­dulai,­a.,­gasparik,­m.,­magyar,­i.,­selmeczi,­i.,­ szabó,­m.,­sztanó,­o.­&­szuromi-korecz,­a.­(2015):­neogene­stratigraphy­in­the­mecsek­region.–­in:­bartha,­i-r.,­kriván,­á.,­magyar,­i.­&­ sebe,­k.­(eds.):­neogene­of­the­paratethyan­region.­6th­workshop­on­the­neogene­ g eo lo gi a c ro at ic a geologia croatica 73/3194 of­central­and­south-eastern­europe.­an­rcmns­interim­colloquium.­programme,­abstracts,­field­trip­guidebook.­2015.05.31-06.03,­orfű.­hungarian­geological­society,­budapest,­102–124. sebe,­k.,­magyar,­i.,­kovačić,­m.,­sztanó,­o.,­botka,­d.,­csoma,­v.,­ szuromi-korecz,­a.,­krizmanić,­k.­&­kovács,­á.­(2019):­lake­pannon­calcareous­marls­in­the­sw­pannonian­basin:­lithology,­stratigraphy­and­bounding­surfaces.–­in:­tari­g.­&­sachsenhofer,­r.­(eds.):­paratethys­petroleum­ systems­between­central­europe­and­the­caspian­region.­aapg,­vienna,­p-50. stevanović,­p.m.­(1961):­pontische­fauna­mit­limnocardium petersi­bei­kadar­an­der­ save­(nordbosnien).–­annales­géologiques­de­la­péninsule­balkanique,­28,­177– 216. sütő-szentai,­m.­(1982):­organic­microplanktonic­biozones­in­the­pannonian­complex­of­central­transdanubia.–­annual­report­of­the­hungarian­geological­institute­ of­1980,­309–344. sütő-szentai,­m.­(1988):­microplankton­zones­of­organic­skeleton­in­the­pannonian­ s.l.­stratum­complex­and­in­the­upper­part­of­the­sarmatian­strata.– acta­botanica­ hungarica,­34/(3–4),­339–360. sütő-szentai,­m.­(1990):­mikroplanktonflora­der­pontischen­(oberpannonischen)­ bildungen­ungarns.–­in:­stevanović,­p.m.,­nevesskaja,­l.a.,­marinescu,­f.l.,­sokać,­a.­&­jámbor­á.­(eds.):­chronostratigraphie­und­neostratotypen.­neogen­der­westlichen­(„zentrale“)­paratethys­viii,­pl1,­pontien.­jazu­ and­sanu,­zagreb-beograd,­842–869. sütő-szentai,­m.­(1991):­szervesvázú­mikroplankton­zónák­magyarország­pannóniai­rétegösszletében.­újabb­adatok­a­zónációról­és­a­dinoflagellaták­evolúciójáról­ [organic-walled­microplankton­zones­of­the­pannonian­in­hungary.­new­data­on­ the­zonation­and­dinoflagellate­evolution.­–­in­hungarian].–­őslénytani­viták­/­discussiones­palaeontologicae,­36–37,­157–200. sütő-szentai,­m.­(1994):­microplankton­associations­of­organic­skeleton­in­the­surroundings­of­villány­mts.–­földtani­közlöny,­124,­451–478. sütő-szentai,­m.­(2000):­organic­walled­microplankton­zonation­of­the­pannonian­ s.l.­in­the­surroundings­of­kaskantyú,­paks­and­tengelic­(hungary).–­annual­report­of­the­geological­institute­of­hungary­of­1994–1995,­153–175. sütő-szentai,­m.­(2011):­az­egerág-7­és­bosta-1.­számú­fúrások­pannóniai­dinoflagelláta­együttesei­(dél-dunántúl)­[pannonian dinoflagellate associations from boreholes egerág no. 7 and bosta no. 1 (southern hungary) – in hungarian].– eacta­naturalia­pannonica,­2,­111–113. sütő-szentai,­m.­&­szegő,­é.­(2008):­organic-walled­microplankton­studies­from­ beds of the sarmatian-pannonian stratotype section at marosorbó (oarba de mures), transylvanian­basin.–­földtani­közlöny,­138,­279–296. soliman,­a.­&­riding,­j.b.­(2017):­late­miocene­(tortonian)­gonyaulacacean­dinoflagellate­cysts­from­the­vienna­basin,­austria.–­review­of­palaeobotany­and­palynology,­244,­325–346.­doi:­10.1016/j.revpalbo.2017.02.003 szónoky,­m.,­dobos-hortobágyi,­e.,­gulyás,­s.,­szuromi-korecz,­a.,­ müller,­p.,­geary,­d.h.­&­magyar,­i.­(1999):­árpád,­a­classic­locality­of­ lake­pannon­bivalves.–­acta­geologica­hungarica,­42/1,­89–108. sztanó,­o.­&­magyar,­i.­(2007):­deltaic­parasequences­on­gamma­logs,­ultra-high­ resolution­seismic­images­and­outcrops­of­lake­pannon­deposits.– joannea­geologie­und­paläontologie,­9,­105–108. sztanó,­o.,­krézsek,­cs.,­magyar,­i.,­wanek,­f.­&­juhász,­gy.­(2005):­ sedimentary cycles and rhythms in a sarmatian to pannonian (late miocene) transitional­section­at­oarba­de­mures/marosorbó,­transylvanian­basin.–­acta­geologica­hungarica,­48,­235–257. sztanó,­o.,­magyari,­á.­&­tóth,­p.­(2010):­gilbert-típusú­delta­a­pannóniai­kállai­kavics­tapolca­környéki­előfordulásaiban­[gilbert­type delta in the pannonian kálla gravel near tapolca, hungary­–­in­hungarian].–­földtani­közlöny,­140/2,­ 167–182. sztanó,­o.,­magyar,­i.,­szónoky,­m.,­lantos,­m.,­müller,­p.,­lenkey,­ l.,­katona,­l.­&­csillag,­g.­ (2013a):­a­tihanyi­ formáció­ a­balaton­ környékén:­típusszelvény,­képződési­körülmények,­rétegtani­jellemzés­[tihany for­ mation in the surroundings of lake balaton: type locality, depositional setting and stratigraphy­–­in­hungarian].–­földtani­közlöny,­143,­73–98. sztanó,­o.,­szafián,­p.,­magyar,­i.,­horányi,­a.,­bada,­g.,­hughes,­d.w.,­ hoyer,­d.l.­&­wallis,­r.j.­(2013b):­aggradation­and­progradation­controlled­ clinothems­and­deep-water­sand­delivery­model­in­the­neogene­lake­pannon,­makó­ trough,­pannonian­basin,­se­hungary.–­global­and­planetary­change,­103,­ ­149–167.­doi:­10.1016/j.gloplacha.2012.05.026 sztanó,­o.,­sebe,­k.,­magyar,­i.­&­csillag,­g.­(2015):­turbidites­as­indicators­ of paleotopography, late miocene lake pannon, western mecsek (hungary).– geologica­carpathica,­66/4,­331–344.­doi:­10.1515/geoca-2015-0029 sztanó,­o.,­kováč,­m.,­magyar,­i.,­šujan,­m.,­fodor,­l.,­uhrin,­a.,­rybár,­s.,­csillag,­g.­&­tőkés,­l.­(2016):­late­miocene­sedimentary­record­ of­the­danube­/­kisalföld­basin:­interregional­correlation­of­depositional­systems,­ stratigraphy­and­structural­evolution.–­geologica­carpathica,­67/6,­525–542.­doi:­ 10.1515/geoca-2016-0033 šikić,­k.,­basch,­o.­&­šimunić,­an.­ (1979):­osnovna­ geološka­ karta­ sfrj­ 1:100000,­tumač­za­list­zagreb­[basic geological map of sfry 1:100000, geology of the zagreb sheet – in­croatian].–­croatian­geological­survey,­department­of­ geology,­beograd,­1–81. šimon,­j.­(1966):­shematski­litostratigrafski­presjek.­litostratigrafske­jedinice­tercijara­ područja­savske­potolone,­istočnog­dijela­dravske­potoline­i­istočne­slavonije­ [translation­ in­english­ –­ in­croatian].–­fond­ stručne­ dokumentacije,­služba­ istraživanja,­ina-naftaplin.­ šimon,­j.­(1980):­prilog­stratigrafiji­u­taložnom­sustavu­pješčanih­rezervoara­sava-grupe­ naslaga­mlađeg­tercijara­u­panonskom­bazenu­sjeverne­hrvatske­[-­in­croatian].–­ unpubl.­phd.­thesis,­university­of­zagreb,­66­p. šujan,­m.,­braucher,­r.,­tibenský,­m.,­fordinál,­k.,­rybár,­s.,­kováč,­ m.­&­asterteam­(2020):­effects­of­spatially­variable­accommodation­rate­on­ channel­belt­distribution­ in­an­alluvial­sequence:­authigenic­10be/9be-based­ bayesian­age-depth­models­applied­to­the­upper­miocene­volkovce­fm.­(northern­ pannonian­basin­system,­slovakia).–­sedimentary­geology,­397.­doi:­10.1016/j. sedgeo.2019.105566 tomljenović,­b.­&­csontos,­­l.­(2001):­neogene–quaternary­structures­in­the­ border­zone­between­alps,­dinarides­and­pannonian­basin­(hrvatsko­zagorje­and­ karlovac­basins,­croatia).–­int.­j.­earth­sciences­(geol.­rundschau),­90,­560–578.­ doi:­10.1007/s005310000176 troskot-čorbić,­t.,­velić,­j.­&­malvić,­t.­(2009):­comparison­of­the­middle­ miocene­and­the­upper­miocene­source­rock­formations­in­the­sava­depression­ (pannonian basin, croatia).– geologia croatica, 62/2,­123–133.­doi:­10.4154/ gc.2009.11 uhrin,­a.,­sztanó,­o.,­csillag,­g.,­hámori,­z.­(2011):­késő-miocén–pliocén­ folyók­rekonstrukciója­a­vértes­délkeleti­előterében­[reconstruction of late mio­ cene – pliocene rivers in south­eastern foreland of the vértes hills – in hungarian].–­földtani­közlöny,­141/4,­363–381. ujszászi,­k.­&­vakarcs,­g.­(1993):­sequence­stratigraphic­analysis­in­the­south­ transdanubian­region,­hungary.–­geophysical­transactions,­38,­69–87. van­gelder,­i.e.,­matenco,­l.,­willingshofer,­e.,­tomljenović,­b.,­ andriessen,­p.a.m.,­ducea,­m.n.,­beniest,­a.­&­gruić,­a.­(2015):­the­ tectonic­evolution­of­a­critical­segment­of­the­dinarides-alps­connection:­kinematic­and­geochronological­inferences­from­the­medvednica­mountains,­ne­croatia.–­ tectonics,­34,­1952–1978,­­doi:­10.1002/2015tc003937 vasiliev,­i.,­bakrač,­k.,­kovačić,­m.,­abdul­aziz,­h.­&­krijgsman,­w.­ (2007):­palaeomagnetic­results­from­the­sarmatian/pannonian­boundary­in­northeastern­croatia­ (vranović­section,­našice­quarry).–­geologia­croatica,­60/2,­ ­151–163.­ velić,­j.­(2007):­geologija­ležišta­nafte­i­plina.– university­of­zagreb,­342­p. vrbanac,­b.­(2002):­chronohorizons­based­on­resistivity­curve­variations­-­upper­ miocene­sediments­of­the­ivanić­grad­formation­in­the­sava­depression­(nw­ croatia).–­geologia­croatica,­55/1,­11–23. vrsaljko,­d.­(1999):­the­pannonian­palaeoecology­and­biostratigraphy­of­molluscs­ from­kostanjek­-­medvednica­mt.,­croatia.–­geologia­croatica,­52,­9–27.­ wijbrans,­j.,­németh,­k.,­martin,­u.­&­balogh,­k.­(2007):­40ar/39ar­geochronology­of­neogene­phreatomagmatic­volcanism­in­the­western­pannonian­basin,­hungary.–­journal­of­volcanology­and­geothermal­research,­164,­193–204.­ doi:­10.1016/j.jvolgeores.2007.05.009 g eologia c roatica sebe et al.: correlation of upper miocene-pliocene lake pannon deposits across the drava basin, croatia and hungary 195 supplement 1. location of outcrops mentioned in the text. 2021 | 74/1 | 1–20 | 13 figs. | 1 tab. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction calciturbidites occur in various sedimentary environments such as continental slopes, toe of slope and single or multiple feeding submarine fans (watts, 1987; rubert et al., 2012; haira­ bian et al., 2015). they can also be associated with different parts of carbonate platforms and platform margins (reijmer et al., 2015a, 2015b). the most important characteristic that distin­ guishes calciturbidites from siliciclastic deposits of the deep sea are the unique diagenetic process of dolomitization, silicification (chert layers or lenses) and micritization (eberli, 1991; ru­ bert et al., 2012; gül, 2015). calciturbidites are generally characterized by poor sorting, local inverse grading, diagenetic micritic layers embedded in the base and nodular silica layering (eberli, 1991). chertification due to diagenesis affects the po­ rosity and permeability of the host rocks (mcbride et al., 1999; saller et al., 2001; behl, 2011). the sedimentation in carbo­ nate gravity systems is controlled by sea level fluctuations, source region, regional basin tectonics and slope characteristics (e.g., eberli, 1991; payros & pujalte, 2008). reijmer et al. (2015a) emphasized that calciturbidites are of interest to the oil and gas industry because of their porous and permeable granular structure. although studies have shown calciturbidites to crop out in various regions with different ages, fewer studies have been car­ ried out on the calciturbidites in comparison to siliciclastic turbi­ dites. the calciturbidites of the babadağ formation (in this manu­ script), are similar to the calciturbidites from the southern lithostratigraphy and sedimentological characteristics of the calciturbidites of the babadağ formation-tavas nappe (sw turkey) basiru mohammed kore1, murat gül1,*, ceren küçükuysal1 and bilal sarı2 1 muğla sıtkı koçman university, faculty of engineering, department of geological engineering, 48000, muğla, turkey; (princebmkore,@yahoo.com; cerenkucukuysal@mu.edu.tr; *corresponding author: muratgul@mu.edu.tr; muratgul.geol@gmail.com) 2 tınaztepe campus, dokuz eylül university, faculty of engineering, department of geological engineering, 35160, buca-i̇zmir, turkey; (bilal.sari@deu.edu.tr) doi: 10.4154/gc.2021.01 abstract the lycian nappes contain slices of ophiolites and sedimentary rocks of various ages that crop out in sw turkey. they evolved and were emplaced under the effect of the late cretaceousmiocene compressional regime. the tavas nappe is part of the lycian nappes and contains jurassic-eocene sediments. the babadağ formation, forming the middle part of the tavas nappe, is composed of limestone at the base and various sized calciturbidites with chert intercalations in the upper part. the standard microfacies classification (smf of flügel, 2004) indicates that the entire unit was deposited mainly in a deep-shelf environment (facies zone – fz-2), deep-sea (fz-1), toe of slope (fz-3) and on the continental slope (fz-4). calcite and quartz dominate the bulk mineralogy of the calciturbidites with higher sio2 and cao weight percentages than other major oxides. additionally, the presence of na2o, k2o, al2o3, mgo, tio2 and fe2o3 is associated with the local sediment input. tectonism and sea level fluctuations were the main triggering factors of the changes in the original depositional environment of the babadağ formation. additionally, grain size and the amount of sediment input control the calciturbidite type and extension. si enriched water circulation and si and ca substitution were responsible for the abundant chert formation during diagenesis of the units. post depositional tectonic activities during transportation and emplacement of the nappes resulted in calcite filled cracks that cut both the calciturbidites and cherts. study of the different nappe slices provides valuable information about synand postdepositional changes of the lithostratigraphic units. provence basin, turonian­cenomanian, france (reijmer et al., 2008, 2012; reijmer et al., 2015a, 2015b); the late triassic­ early jurassic of northern hungary (haas et al., 2010); jurassic tethys oceanic carbonate deposits of eastern alps­switzerland (eberli, 1987); the early cretaceous of the manim unit, west­ ern carpathians slovakia (michalik et al., 2012); the late cretaceous of the ionian basin­central albania (dewever et al., 2007) and the cretaceous of the othris mountain­hellenide zone and eastern greece (price, 1977). some older calciturbi­ dites were reported in different countries; the silurian­devonian calciturbidites of the barrandian region­czech republic, (va­ cek, 2007); the early­middle triassic sumeini group, maqam formation, northernmost arabian carbonate platform (watts, 1987); and the triassic pedata / potschen formation calciturbi­ dites­austria (reijmer et al., 1991). in turkey, robertson & woodcock (1981) docu­ mented the upper triassic calcareous clastics and the jurassic­ lower cretaceous siltstone­radiosphere­chert­mudstone­lime­ stones and black shales in antalya­sw turkey. sofracioğlu & kandemi̇r (2013) and sari et al. (2014) reported the upper mesozoic calciturbidites in the eastern pontides­ne turkey. özcan et al. (2012) mentioned the upper cretaceous­eocene pelagic micrites and calciturbidites of the black sea shoreline and the western pontides–n turkey. solak et al. (2015) docu­ mented some upper cretaceous calciturbidites in the bornova flysch zone in the manisa­spil mountain–w turkey (fig. 1). article history: manuscript received december 19, 2019 revised manuscript accepted october 14, 2020 available online february 28, 2021 keywords: facies zone – standard microfacies (fz – smf, flügel, 2004), deep-sea, lycian nappes, muğla-sw turkey. mailto:muratgul@mu.edu.tr mailto:muratgul.geol@gmail.com g eo lo gi a c ro at ic a geologia croatica 74/12 upper part of the babadağ formation require additional studies for a complete understanding of the carbonate gravity­flow de­ posits. therefore, this study aims (1) to determine the detailed sedi­ mentological characteristics of the calciturbidites of the babadağ formation mapped as separated slices which together comprise the tavas nappe (fig. 2), and (2) to unravel the depositional environment and controlling factors on the calciturbidite sedi­ ments. 2. geological setting sw turkey contains three major geological units; the beydağları autochthone, the southern menderes massif and the lycian nap­ pes allochthones which crop out between these two autochthones (fig. 1). the beydağları autochthone includes late triassic­creta­ ceous platform carbonates and the lutetian­miocene sediments (fig. 3; ersoy, 1990; şenel et al., 1989, 1994, 1998; sari & özer, 2001; 2002; sari et al., 2004; sari, 2006; 2017; şenel, 2004, 2007; soycan et al., 2015). the core of the southern part of the menderes massif contains gneiss and meta­gabbro at the core; the cover part includes upper devonian­early eocene am­ the lycian nappes are sandwiched between the beydağları autochthone to the south and the menderes massif to the north in the tauride­anatolide platform of turkey (fig. 1). they are mainly composed of allochthons with remnants of oceanic crust that encompass diverse deep­water and platform type deposits (danelian et al., 2006; göncüoğlu, 2011; moix et al., 2013; sari, 2017). the lycian nappes (including deep­water sediments of the tavas nappe), have since become a subject of widespread interest for numerous researchers over the last four decades, focusing on the fossil content and local lithological chara­ cteristic of the units (yilmaz, 1981; erakman et al., 1982; şengör et al., 1984; okay, 1989; şenel et al., 1994; ko­ zur, 1998; collins & robertson, 1998, 1999; özcan et al., 2012; gül et al., 2013; gül, 2015; soycan et al., 2015; sari, 2017). however, determination of the differences of nappe slices, which are thought to be the product of the same environ­ ment and when separated are mapped under the same nappe name, can provide valuable information about the primary­origi­ nal depositional environment. this depositional environment can be quite large. as a result, the lithological­compositional­ textural­structural differences detected in each nappe slice can help identify the characteristics of the depositional environment both syn­ and post­ sedimentation. thus, calciturbidites in the figure 1. a location map of the study area, and main tectonic units and structural lines of the eastern mediterranean (modified from robertson & dixon, 1996). g eologia c roatica kore et al.: lithostratigraphy and sedimentological characteristics of the calciturbidites of the babadağ formation-tavas nappe (sw turkey) 3 phibolite­schist­phyllite and marble (şengör et al., 1984; can­ dan et al., 1998; bozkurt, 2001; dora, 2007; bozkurt, 2004). the lycian nappes consist of south­imbricated nappes, investigated under different names (graciansky et al., 1967; graciansky, 1968; brunn et al., 1971; poisson, 1977; yilmaz, 1981; erakman et al., 1982; şengör et al., 1984; tekeli̇, 1984; okay, 1989; ersoy, 1990, 1991; şenel et al., 1994; şenel, 1997a, 1997b; kozur, 1998; collins & ro­ bertson, 1998, 1999, 2003; konak, 2003; danelian et al., 2006; şenel, 2004, 2007; göncüoğlu, 2011; vachard & moix, 2011; özcan et al., 2012; moix et al., 2013). şenel et al. (1994) separated and mapped six main nappe sheets in the northern part of the lycian nappes; the tavas nappe, the bodrum nappe, the dumanlıdağ nappe, the domuzdağ nappe, the gül­ bahar nappe and the marmaris ophiolite nappes (figs. 2, 3). the geological map (fig. 2) reveals that the studied locations are surrounded mainly by the çökek unit of the bodrum nappe, together with the marmaris peridotite and ağla unit of the gül­ bahar nappe. the çökek unit contains the upper triassic­liassic shallow carbonate shelf product of the kayaköy dolomite; the dogger­malm reef front dolomite­dolomitic limestones of the sandak formation; the cretaceous continental slope­deep sea ba­ sin products of calciturbidites and cherty micrites of the göçgediği formation; and the upper senonian flysch and limestone­bearing karaböğürtlen formation deposited under variable deep sea basin conditions. the ağla unit includes the middle­upper triassic mafic volcanics, radiolarites and cherty limestone deposited in the deep sea environment. the marmaris peridotite is composed of the lower cretaceous harzburgite, gabbro and diabase (figs. 2, 3; şenel, 1997a, 1997b, 2004, 2007; soycan et al., 2015). figure 2. the tectonic units of the study area, and location of the measured stratigraphic sections (1: babadağ sections locations, 2: karadon sections locations, 3: yangı section location) and detailed observation place (4: bozburun hill location) (modified from şenel, et al., 1989, 1994; şenel, 1997a, 1997b, 1997c). g eo lo gi a c ro at ic a geologia croatica 74/14 the tavas nappe (triassic­eocene) unconformably overlies the karadağ series (carboniferous­triassic limestone, dolomite and dolomitic limestone; quartz sandstone; shale) and the teke­ dere series (upper permian recrystallized limestones, volcanic and bedded chert interbedded green sandstone, limestone, dolo­ mite and dolomitic limestone); and tectonically overlies the yeşilbarak nappe (upper cretaceous limestone, eocene clastics and limestone and lower miocene clastics and limestone), (figs.. 2, 3; şenel et al., 1994; şenel, 1997a, 1997b, 1997c, 2004). the tavas nappe from bottom to top is characterized by rock as­ semblages of the rhaetian­lower liassic sandstone, conglomera te and mudstone of the çenger formation deposited initially in the continental (fluvial and fan) and later shore­backshore environ­ ment; the liassic algae, coral bearing limestone, and dolomitic limestone with chert micrites, chert and shale bearing ağaçlı formation (a product of the stable shallow carbonate shelf); the toarcian­maastrichtian limestones­calciturbidites of the babadağ formation deposited in the continental slope and basin; and the upper palaeocene­middle eocene mafic volcanics, micrite, breccia, and sandstone of the faralya formation (products of variable depositional environment conditions), (fig. 3; şenel, 1997a, 1997b; şenel, 2007). a middle jurassic age was proposed for the lower parts of the babadağ formation from radiolarians, benthic foraminifera in tavas town (nw of the study area, fig. 1; soycan et al., 2009, 2011, 2015). in and around the towns of fethiye and köyceğiz (fig. 2), the babadağ formation contains a red micritic member at the base (including ammonitico-rosso facies, locally breccia and chert, with the age of the member reported as upper toarcian), an oolite bearing limestone member in the middle part (locally with peloid and nodular chert), has a reported age as upper dogger – malm. planktonic­benthic foraminifera and rud­ ist fragment bearing calciturbidites, globotruncana sp. and chert bearing micritic limestone form the upper member of the forma­ tion (şenel, 1997a, 1997b). this upper member of the babadağ formation including calciturbidites in bozburun hill was studied in detail by gül (2015) and sari (2017). sari (2017) deter­ mined rudist shell fragments, benthic foraminifera (orbitoidae) and rare gastropods (denoting the late maastrichtian) in the up­ permost part of the bozburun hill, and defined several different forms of globotruncana sp. from foraminiferal bearing wacke­ stones in the lower part (designated as being of late campanian­ late maastrichtian age). 3. materials and methods four locations were selected in an attempt to achieve the objec­ tives of this study depending on forestry­maquis cover, road ac­ cess and exposure quality. a total of six sedimentary sections were measured at three different locations on babadağ mountain (babadağ­1, 50m; babadağ­2, 120 m; babadağ­3, 100 m; location 1 in figs. 2, 4a), ortaca town (karadon­1, 30 m; karadon­2, 20 m; location 2 in figs. 2, 4b) and yangı village (yangı section, 170 m; location 3 in figs. 2, 4c). the bozburun hill area is another study location (location 4 in fig. 2). this region has already been documented in previous studies (gül et al., 2013; gül, 2015; sari, 2017) due to its visible exposures in the field; however, the sedimentary textures, structures, and lateral and vertical facies changes have not been previously documented. based on litho­ logical variations, sampling was carried out at 1­2 m intervals for mineralogical, chemical and petrographic analyses. a total of ninety­nine samples were collected during the field studies (22 from the babadağ sections; 40 from the karadon sections; 23 from the yangı section, 14 from the bozburun hill region); eighty­four thin sections (22 from the babadağ sections; 26 from the karadon sections; 22 from the yangı section, 14 from the bozburun hill region) were prepared in the thin section prepa­ ration laboratories at the general directorate of mineral re­ search and exploration (mta, ankara, turkey). the thin sec­ tions were examined under binocular petrographic microscopes and the grain­size of the calciturbidites was determined at the figure 3. allochthonous and autochthonous units in the western taurides (f: formation; black star: studied formation; after şenel et al., 1997a; soycan et al. 2015). g eologia c roatica kore et al.: lithostratigraphy and sedimentological characteristics of the calciturbidites of the babadağ formation-tavas nappe (sw turkey) 5 department of geological engineering at muğla sıtkı koçman university. in this study we preferred to use the terms calcilutite (clay size), calcisiltite (silt size), calcarenite (sand size) and calcirudite (gravel size) to classify the calciturbidites in terms of the known grain sizes proposed by previous studies (grabaua, 1904; ud­ den, 1914; wentworth, 1922; folk, 1980; flügel, 2004). a combined classification scheme of folk (1962), dun­ ham (1962) and embry & klovan (1971) was followed for carbonate rocks. the classification of flügel (2004) was used to differentiate the samples according to the proposed standard microfacies classification (smf) to understand the depositional characteristics (price, 1977; watts, 1987; reijmer et al., 2008, 2012; haas et al., 2010; rubert et al., 2012). the mineralogical compositions of the samples were deter­ mined by the x­ray diffraction method. thirty representative sam­ figure 4. measured sedimentary logs of calciturbidites (a) babadağ sections (a1, a2, a3), (b) karadon sections (b1, b2), (c) yangı section. g eo lo gi a c ro at ic a geologia croatica 74/16 ples of calcilutites and fine­grained calcarenites (nine from the babadağ sections; eleven from the karadon sections; five from the yangı section, and five from the bozburun hill region) were analy­ sed by a panalytical expert pro diffractometer equipped with a cu tube at 40kv voltage and 30ma current with a scanning rate of 2°/min at the mineralogy­petrography laboratory at the general directorate of mineral research and exploration (ankara, turkey). x­ray fluorescence analysis was performed to determine the major oxide compositions of 30 calciturbidite samples. gül (2015) stated that microcrystalline­cryptocrystalline cherts are present in the calciturbidite levels, however he did not address their diagenetic properties and textures. sem­eds analyses through cross­sections were carried out at the research and application centre for re­ search laboratories at muğla sıtkı koçman university (muğla, turkey). the specimens were sputter coated with gold (emitech k550x sputter coating systems). samples were examined under a scanning electron microscope (sem) (jeol jsm­7600f, japan) at an accelerating voltage of 15 kv. elemental characterizations of the samples were done using the sem equipped with energy disper­ sive x­ray spectrometry (eds­oxford instrument). figure 4. continued. g eologia c roatica kore et al.: lithostratigraphy and sedimentological characteristics of the calciturbidites of the babadağ formation-tavas nappe (sw turkey) 7 4. results 4.1. lithostratigraphy of the babadağ formation this study focuses on the calciturbidites of the babadağ forma­ tion and its lithological features. the babadağ formation is com­ posed mainly of calcilutite, calcisiltite, in some parts calcarenite and rarely calcirudite in its upper parts (şenel, 1997a, 1997b; gül, 2015; sari, 2017). babadağ sections: these sections were measured at babadağ mountain, which is located at 5­6 km south west of fethiye town (fig. 2). in this region, the babadağ formation con­ formably overlies the ağaçlı formation and is overlain by the figure 5. field photographs showing the lithological properties of calciturbidites in several stratigraphic levels of the babadağ sections. (a) general view of calciturbidites in babadağ. (b) thick bedded calcilutite with chert bands, (c) grey-coloured, thin bedded calcilutite, (d) dark-grey, thin bedded calcarenite, (e) thin bedded calcarenite cut by fault, (dotted line shows the boundary between the deformed and undeformed parts of the calcarenite) (f ) grey coloured, thick bedded calcilutite with chert bands. g eo lo gi a c ro at ic a geologia croatica 74/18 faralya formation (fig. 3). in addition, some levels of the babadağ formation are tectonically overlain by the bodrum nappe. the large part of babadağ mt. is covered with forests, making it difficult to find a straight section to measure (fig. 4a). some exposures were difficult to reach due to lack of proper roads and the risk of rock falls. observations showed that the unit was faulted, folded, overturned, and highly deformed. strati­ graphic sections were measured from the possible top point of the babadağ mountain, through the pathways opened for babadağ paragliding centre. the babadağ­1 section (50 m) measured (fig. 4a1) at the up­ per part is considered to be the youngest part of the babadağ for­ mation (fig. 5). the babadağ­2 section (120 m) (fig. 4a2) was measured in the faulted and folded middle part of the babadağ formation. the babadağ­3 section (100 m) (fig. 4a3) was mea­ sured in the lowermost part of the formation. the babadağ­1 and babadağ­2 sections were formed by the alternations of pink­grey, thin (3­5 cm) – medium (15­20 cm) thick bedded (30­40 cm), ero­ sive based, truncated topped, calcilutite­calcarenite units in places. thin­layered (2­3 cm), locally slumped, chert bands and lenses are observed at the base of the unit, however they are mostly absent in the upper levels. moreover, the babadağ­3 sec­ tion contains thin bedded (2­5 cm) calcilutite and thin to medium bedded (4­15 cm) calcarenite alternation with chert bands (3­5 cm thick, 5­20 m long) and lenses (5­10 cm thick, 30­50 cm long) (fig. 4a; kore, 2018). karadon sections: the karadon sections are located to the nw of dalaman town (fig. 2). calciturbidite layers are exposed along the road cut to the south of ortaca town. the babadağ for­ mation is normally faulted in the eastern part and covered with figure 6. field photographs showing the calciturbidites in karadon sections. (a) general view of calciturbidites in karadon area, (b) pinkish-grey calcilutite with chert bands, (c) reddish-grey, fine-grained calcarenite with chert-bands, (d) thick bedded calcilutite with chert-band, (e) fine-grained calcarenite with slumped chert. g eologia c roatica kore et al.: lithostratigraphy and sedimentological characteristics of the calciturbidites of the babadağ formation-tavas nappe (sw turkey) 9 alluvium. within the karadon neighbourhood, the marmaris ophiolite nappe tectonically overlies the unit, while the faralya formation consisting of volcanic rocks and young sediments un­ conformably overlies the unit in the western part. the karadon­1 section is 29 m thick (figs. 4b1, 6). at the base, there are sub­levels of highly broken­fragmented calcitur­ bidites. the next 4 m consists of thin bedded (2­7 cm) calcilutites intercalated with thin to medium bedded (2­15 cm) calcarenite (fig. 4b1). the subsequent 17 metres (between 4 m and 21 m) contains alternations of pinkish grey, laminated to thinly (2­5 cm) undulating bedded calcilutite­ thin to medium bedded (2­15 cm) undulating calcarenite, as well as slumped, red­grey chert bands (3­10 cm thick, 3­15 m long) and lenses (5­30 cm thick, 15 cm­ 2 m long) (figs. 6b­6e). the next 8 metres contains laminated to thinly bedded (2­5 cm) calcilutite and thin to medium bedded (2­ 15 cm) calcarenite layers without chert (fig. 4b1). the karadon­2 section was measured from the southern wing of the small fold that contains pinkish­grey coloured, laminated to thinly bedded (2­5 cm thick), locally undulating calcilutite and thin to medium (2­15 cm) locally undulating bedded and slumped calcarenite and calcirudite, red­grey chert bands (1­10 cm thick, 7­15 m long) and lenses (3­10 cm thick, 30 cm­ 2 m long) (fig. 4b2). yangı section: this section was measured in yangı village about 2­3 km northeast of köyceğiz (fig. 2). a 170 m thick cal­ citurbidite succession was measured. the yangı section is com­ posed predominantly of thin (2­5 cm)­medium­thick (10­17 cm) bedded, undulating, cream­yellow­grey­reddish coloured lami­ nated calcilutite, laminated calcisiltite and fine­grained calcareni te (figs. 4c, 7). large chert nodules were observed near to the middle of the unit. unlike the chert observed in other areas, these were figure 7. field photographs showing the calciturbidites in the yangı section; (a) general view of calciturbidites in the yangı section, (b) grey coloured calcilutite, (c) yellow, laminated, thin bedded calcilutite, (d) undulating, thin bedded calcilutite, (e) yellow, pink coloured undulating bedded calcilutite. g eo lo gi a c ro at ic a geologia croatica 74/110 found to be irregularly shaped (20­30 cm thick, 1­3 m long). a slump was identified at 110 metres in the section (fig. 7). bozburun hill: bozburun hill is located on a different nappe slice, about 10 km southwest of the karadon section. on the boz­ burun hill, calciturbidites of the babadağ formation overlie the older tavas nappe deposits, and are unconformably overlain by the faralya formation. the bozburun hill was previously studied in detail (gül et al., 2013; gül, 2015; sari, 2017). they re­ ported that bozburun hill is composed of mainly laminated and thinly (2­5 cm) undulating, bedded calcilutite at the base, lami­ nated, thin (4­8 cm) to medium (10­25 cm) bedded calcarenite­ mainly laminated and thinly (2­5 cm) undulating, bedded calci­ lutite alternations with chert layers in the middle, while thin (4­8 cm) to medium (10­25 cm) bedded calcarenites­ medium (10­25 cm) to thickly (30­100 cm) bedded calcirudites dominate the up­ permost part of the succession (fig. 8). 4.2. petrography and compositional changes babadağ sections: a total of twenty­two samples from the babadağ sections were examined petrographically. these sam­ ples are mainly characterized as micritic mudstone, wackestone, packstone and sparitic grainstone (dunham, 1962; embry & klovan, 1971). however, there are minor occurrences of float­ stones and rudstones (embry & klovan, 1971). smf 3 (well sorted; micrite, fosiliferous micrite, mudstone­ wackestone; contains planktonic foraminifera, rudist shell frag­ ments, calcite infillings through the cracks) and smf 5 (well­ moderately­poorly sorted; packed biomicrite packstone, unsorted biosparite­grainstone; includes whole fossil and fossil fragments (rudist), calcites with perfect cleavages, large calcite infillings) type micro facies are dominant facies in babadağ sections. smf 4 (well­moderately­poorly sorted; packed biomicrite­wackestone, packstone; consist of fossil fragments (rudist), and calcite infill­ ings), smf 6 (poorly sorted; packed biomicrite, rudstone; in­ cludes rudist fossil (size > 2 mm and the ratio > 10 %), and calcite filling the cracks) and smf 8 (moderately sorted; fosiliferous bio­ micrite, wackestone; made up of rudist fragments, and calcite infillings) are other less common components (figs. 4, 9a, 9b). petrographic studies reveal the presence of chert, dolomite, cal­ cite, quartz, micrite, planktonic foraminifera and rudist frag­ ments (figs. 9a, 9b). the samples were interpreted as medium­ thin laminated calcilutite and calcarenite. they characterize deposition in the deep sea (facies zone (fz)­1), deep shelf (fz­ 2), toe­shelf (fz­3), and slope (fz­4) environments (fig. 10). figure 8. field photographs showing the calciturbidites in bozburun hill; (a) general view of calciturbidites in bozburun hill; (b) thick bedded layered calcilutite with abundant chert bands and lenses; (c) calcilutite with chert lenses. g eologia c roatica kore et al.: lithostratigraphy and sedimentological characteristics of the calciturbidites of the babadağ formation-tavas nappe (sw turkey) 11 figure 9. photomicrographs of the babadağ formation; a) cross polarized microview of the silicification and dolomitization of smf-3 facies in the babadağ sections; b) cross polarized microview of the relatively coarser quartz mineral replacing calcite of fossil fragments; c) calcilutite-smf-3 showing an undulatory contact with calcisiltite-smf-5. micritization and or recrystallization may lead to this type of contact. coarser-grained sediment transportation may also lead to an erosive contact with soft-finer-grained sediment; d) cross polarized microview of the smf-5 in the karadon sections; e) calcilutite-smf-3 has an undulatory contact with calcisiltite-smf-5; f ) cross polarized view of silicification in the yangı section; g) microview of the smf-3 facies in bozburun hill; h) intraclast and coarse-grained fossil fragments bearing smf-5 facies in the bozburun hill (q: quartz, ch: chert; do: rhombohedral dolomite; ca: calcite; pl: planktonic foraminifera). g eo lo gi a c ro at ic a geologia croatica 74/112 karadon sections: twenty­six samples from the karadon sections were examined under the petrographic microscope (figs. 9c, 9d, 9e). the studied samples are micritic mudstone­pack­ stone­wackestone­bindstone, and floatstone, and sparitic grain­ stone (dunham, 1962; embry & klovan, 1971). smf 3 (very well­well­moderately sorted; fosiliferous micrite, mud­ stone­wackestone; includes planktonic foraminifera, sometimes rudist fossil fragments, and calcite infillings) and smf 5 (well­ moderately­poorly sorted; packed biomicrite, packstone, un­ sorted biosparite­grainstone, fosiliferous biosparite­floatstone; consist of calcite filling the fractures, whole (planktonic fo­ raminifera) and fragments of fossil (rudist), and stylolite) type facies are the dominant facies. smf 4 type (very poorly sorted; unsorted biomicrite, packstone; made up of silt­sand size fossil fragment­rudist) is the other less common component (figs. 9c, 9d, 9e). they characterize the deposition in deep sea (fz­1), deep shelf (fz­2), toe­shelf (fz­3), and slope (fz­4) (fig. 10). yangı section: twenty­two samples from the yangı section were subjected to microscopic examination and are predomi­ nantly of micritic mudstone­floatstone (fosiliferous biomicrites) and sparitic rudstone (unsorted biosparite)­grainstone (dun­ ham, 1962; embry & klovan, 1971; figs. 4, 9f) composi­ tion. smf 3 (well­moderately­poorly sorted; micrite, fosiliferous micrite, mudstone­wackestone; consist of whole planktonic fo­ raminifera, rudist shell fragments, calcite infillings) is the domi­ nant facies in the yangı section. smf 5 is well­moderately­poorly sorted; packed biomicrite­packstone, unsorted biosparite­grain­ stone; containing whole fossil (planktonic foraminifera) and fos­ sil fragments (rudist), and large calcites with perfect cleavages and infillings), smf 4 is well­poorly sorted; unsorted biomicrite, packstone; made up of silt­sand size fossil fragment, rudist. smf 6 is very well sorted; packed biomicrite, rudstone; includes rud­ ist fossil (their size larger than 2mm and their ratio > 10 %), and calcite filling the cracks. smf 8 (moderately­poorly sorted; fo­ siliferous biomicrite, wackestone­floatstone); made up of rudist fragments (size> 2mm and the ratio > 10 %), calcite infillings) are other secondary components. chert and calcite are dominant in the yangı section (fig. 9f). they characterize the deposition in deep sea (fz­1), deep shelf (fz­2), toe­shelf (fz­3), and slope (fz­4) (fig. 10). bozburun hill: fourteen samples from the bozburun hill were studied. these are dominated by micritic packstone­mud­ stone­wackestone with minor floatstone, and sparitic grainstone (dunham, 1962; embry & klovan, 1971; figs. 9g, 9h). smf 3 (well sorted; fosiliferous micrite, mudstone­wackestone; consist of planktonic foraminifera, rudist shell fragments, calcite infillings through the cracks) and smf 5 (well­moderately­poorly sorted; packed biomicrite­packstone, unsorted biosparite­grain­ stone; contain whole fossil and fossil fragments (rudist and ben­ thic foraminifera fragments), and large calcites with perfect cleavages filling the cracks) are the main facies types. smf 4 type (poorly sorted; packed biomicrite­packstone; includes fossil frag­ ments (rudist), calcite infillings) is the secondary component. cal­ cite, dolomite, quartz, micrites, and planktonic foraminifera figure 10. standard microfacies (smf) and the related facies zone (fz) of samples were described according to flügel (2004) classification (rimmed carbonate platform) and facies model (smf: standard microfacies, fz: the facies zone). g eologia c roatica kore et al.: lithostratigraphy and sedimentological characteristics of the calciturbidites of the babadağ formation-tavas nappe (sw turkey) 13 (sari (2017) defines different forms of globotruncana sp.) are common in the samples (figs. 9g, 9h). they characterize depo­ sition in deep sea (fz­1), deep shelf (fz­2), toe­shelf (fz­3), and slope (fz­4) (fig. 10). 4.3. whole rock mineralogy and geochemistry x­ray diffractograms reveal the dominance of quartz and calcite in all samples (fig. 11). quartz is observed with its prominent peak of 3.34 å at 26° 2θ; while intense reflection of calcite is de­ termined at 29° 2θ with 3.03 å d­spacing. dolomite with very weak intensity at around 31° 2θ and 2.89 å d­spacing is also re­ cognized in the diffractograms (figs. 11a, b, c, d). the mineralo­ gical findings on the bulk compositions are consistent with the microscopic observations. the calciturbidite layers away from the chert lenses­bands contain calcite minerals of various sizes. the regional and one­ line scan­mode analysis on these layers by sem­eds confirms the dominance of ca, c and o as the major elements. si amount is negligible. on the other hand, sem­eds analysis on the sam­ ple from bozburun hill, close to the chert bands and lenses, points to the si enrichment and ca depletion, indicating the diagenetic replacement of ca by si (fig. 12). additionally, micro­cryp­ tocrystalline calcite and quartz minerals are observed under sem (fig. 12 a, c, d). the eds results are compatible with the mine­ ral compositions (fig. 12b). figure 12e is the image of one­line sem­eds analysis which illustrates the presence of the elements si, ca, mg and c. ca enrichment with very low si content at the beginning of the measured line is associated with micro­cryp­ tocrystalline calcite; whereas a higher si content was determined towards the end of the line with negligible ca. very low and al­ most negligible amounts of mg are also recorded by eds scan. xrf results of the 30 samples are presented in weight per­ centages (wt.) in table 1. a high purity­chert sample has more than 80% sio2, while calciturbidite samples away from the cher­ tification or silicification intervals include predominantly >50 % cao (table 1). calciturbidite samples affected by silicification contain 0.2­30 % sio2. this inverse relationship between si and ca is also confirmed by sem­eds observations (fig. 13). the babadağ, karadon sections, and bozburun hill samples show similar chemical compositions of very low alkali and alkaline earths. however, a few samples of the yangı section have two to four times higher values of the na2o, k2o, al2o3, mgo, tio2 and fe2o3 values than the average values of the other sections (table 1). loi (loss of ignition values) values are in coherence with the ca­enriched samples (table 1). 5. discussion 5.1. sedimentary features and related depositional environments the lycian nappes units were originally attributed to the south­ ern part of the northern branch of the neotethys ocean located north of the menderes massif (fig. 1) (şengör & yilmaz, 1981; collins & robertson, 1998; okay, 2001). they mi­ grated to the south passing over the menderes massif units and were emplaced between the menderes massif and the beydağları autochthone (fig. 1; şenel, 1997a; kozur et al., 1998; ro­ bertson, 2000; bozkurt, 2004). the map of the triassic­ cretaceous palaeogeography of the eastern mediterranean indi­ cates that the northern neotethys ocean extended from greece (pelagonian zone, pindos zone, cyclades etc.) in the west to iran in the east including the taurides (western taurides, lycian nappes, beyşehir­hoyran­hadim nappes etc.) (fig. 1; robert­ son & dixon, 1996; robertson & mountrakis, 2006; vachard & moix, 2011). the lycian nappes represent a tran­ sition zone between the greek hellenides and the central­eastern taurides–turkey (moix et al., 2013). the late cretaceous period was represented by a compressional regime that led to the frag­ mentation­nappe formation and locally different depositional set­ tings, such as carbonate platform, continental slope, and deeper marine environments in the neotethyan ocean (robertson & dixon, 1996; robertson & mountrakis, 2006; vachard & moix, 2011). the cenomanian­coniacian rudist bearing limestones and the cenomanian­campanian micritic limestone are unconforma­ bly overlain by the campanian? – maastrichtian units of breccia, conglomerates, carbonated sandstones (calciturbidites?) and pe­ figure 11. xrd patterns of the studied samples in (a) babadağ sections, (b) karadon sections, (c) yangı section, and (d) bozburun hill. g eo lo gi a c ro at ic a geologia croatica 74/114 figure 12. (a) general sem images of sample 14 from bozburun hill. (b) regional eds analysis on the red rectangle in figure a. (c) sem view of the micro-cryptocrystalline quartz bearing chert part of figure a. (d) sem view of the micro-cryptocrystalline calcite mineral bearing calcilutite of figure a. (e) one-line scan mode eds analysis on sample 14 indicating an inverse relation between si and ca elements proving that si replaced the ca during the diagenesis. g eologia c roatica kore et al.: lithostratigraphy and sedimentological characteristics of the calciturbidites of the babadağ formation-tavas nappe (sw turkey) 15 lagic limestones with globotruncana sp. in the bornova flysch zone in the manisa­spil mountain on the western end of the i̇zmir­ankara zone in the northern part of the northern neo­ tethyan ocean (solak et al., 2015 and references therein). dur­ ing the campanian? – maastrichtian period the platform was drowned and transformed into the outer platform and continental slope environment (solak et al., 2015). similar age data was reported for the upper part of the babadağ formation in the boz­ burun hill area (sari, 2017, and references therein). similar planktonic foraminiferal content was also observed in the babadağ sections, the karadon sections and the yangı section. however, there is no detailed palaeontological analysis of the fos­ sil content. the northern neotethyan ocean covered large areas of the northern part of the menderes massif (şengör & yilmaz, 1981). this ocean hosted important limestone, calci­ turbidite deposits, rudist reefs, and ophiolites (şengör & yilmaz, 1981). dependent on compressional regime during the late cretaceous, nappe slices of this ocean were transported to the south and formed the lycian nappes, some slices were trans­ ported to the north and formed the bornova flysch zone (şengör & yilmaz, 1981). upper cretaceous calciturbidite deposits with rudist frag­ ments and planktonic foraminifera were reported from the ana­ mas­akseki autochthone, the antalya nappes and the alanya nappes of the southern branch of the neotethys ocean (şenel et al., 1998). in the southern part of the central taurides, within the upper levels of the geyikdağı tectonic unit, chert, brecciated sandy, micritic limestone alternations (campanian) and then dark red coloured pelagic limestone and slumped hemipelagic lime­ stone (upper campanian) of the cehennemdere formation were observed by koç et al. (2016). the existence of similar units was also reported from west of the study area. clift & robertson (1990) reported that the argolis peninsula in southern greece contains upper creta­ ceous pelagic limestones, calciturbidites, limestone­conglomera­ tes and slumped units in the middle of the hellenides. skourt­ sis­coroneou et al. (1995) reported that the ionia zone of the hellenides in western greece contains the tithonian­early san­ tonian pelagic limestone with chert and the upper santonian­ maastrichtian detrital limestone with chert nodules. similarly, le goff et al. (2015) reported deformed gravity­flow deposits within the ionia basin. the pindos zone in western greece also table 1. major oxide compositions (wt.%) of the studied calciturbidite samples major oxide (wt.%) sio2 tio2 al2o3 fe2o3 mgo cao na2o k2o p2o5 mno loi babadağ section b1 86.90 0.10 0.20 0.60 0.10 6.60 0.10 < 0.10 < 0.10 0.10 5.30 b2 30.40 0.10 0.10 0.20 0.30 37.80 0.10 < 0.10 < 0.10 0.10 30.90 b3 1.60 0.10 0.30 0.30 0.40 54.00 0.10 0.10 < 0.10 0.10 43.00 b4 0.50 0.10 0.20 0.10 0.40 54.80 0.10 0.10 < 0.10 0.10 43.60 b5 0.60 0.10 0.20 0.10 0.30 54.90 0.10 < 0.10 < 0.10 0.10 43.60 b6 0.40 0.10 0.10 0.10 0.40 54.90 0.10 < 0.10 < 0.10 0.10 43.80 b7 0.70 0.10 0.10 0.10 0.30 55.00 0.10 <0.10 < 0.10 0.10 43.50 b8 0.20 0.10 0.20 0.10 0.30 54.80 0.10 <0.10 <0.10 0.10 44.10 b9 18.40 0.10 0.10 0.10 0.40 55.00 0.10 < 0.10 < 0.10 0.10 25.70 average 15.52 0.10 0.17 0.19 0.32 47.53 0.10 <0.10 <0.10 0.10 35.94 karadon section k1 0.60 0.10 0.10 0.10 0.30 54.90 0.10 < 0.10 < 0.10 0.10 43.70 k2 2.00 0.10 0.20 0.10 0.30 54.20 0.10 < 0.10 < 0.10 0.10 42.90 k3 22.20 0.10 0.50 0.20 0.30 42.20 0.10 0.10 < 0.10 0.10 34.20 k4 47.70 0.10 0.30 0.30 0.20 28.50 0.10 < 0.10 < 0.10 0.10 22.70 k5 18.30 0.10 0.20 0.20 0.30 44.60 0.10 < 0.10 < 0.10 0.10 36.10 k6 1.50 0.10 0.50 0.40 0.40 53.80 0.10 0.10 0.10 0.10 42.90 k7 0.40 0.10 0.10 0.10 0.30 55.10 0.10 0.10 0.10 0.10 43.50 k8 53.30 0.10 0.30 0.40 0.20 25.10 0.10 0.10 0.10 0.10 20.20 k9 0.30 0.10 0.10 0.10 0.30 55.00 0.10 0.10 0.10 0.10 43.70 k10 0.40 0.10 0.10 0.10 0.30 55.10 0.10 0.10 0.10 0.10 43.50 k11 0.40 0.10 0.10 0.10 0.30 55.10 0.10 0.10 0.10 0.10 43.50 average 13.37 0.10 0.23 0.19 0.29 47.60 0.10 0.10 <0.10 0.10 37.90 yangi section y1 18.40 0.20 5.10 2.20 1.00 39.00 0.40 0.90 0.10 0.10 32.60 y2 18.40 0.20 5.10 2.10 1.00 39.10 0.50 0.90 0.10 0.10 32.50 y3 18.30 0.20 4.10 1.80 0.80 40.10 0.60 0.60 0.10 0.10 33.30 y4 0.30 0.10 0.10 0.10 0.30 55.10 0.10 < 0.10 <0.10 < 0.10 43.90 y5 0.30 0.10 0.10 0.10 0.30 55.10 0.10 < 0.10 < 0.10 <0.10 43.90 average 11.14 0.16 2.90 1.26 0.68 45.68 0.34 0.80 <0.10 <0.10 37.24 bozburun hill samples bh1 0.40 0.10 0.10 0.10 0.40 54.80 0.10 < 0.10 < 0.10 < 0.10 44.00 bh2 0.50 0.10 0.10 0.20 0.30 54.80 0.10 < 0.10 < 0.10 < 0.10 43.90 bh3 0.90 0.10 0.10 0.20 0.30 54.80 0.10 <0.10 < 0.10 < 0.10 43.50 bh4 0.60 0.10 0.20 0.10 0.40 54.60 0.10 < 0.10 < 0.10 < 0.10 43.90 bh5 0.90 0.10 0.20 0.10 0.20 54.70 0.10 < 0.10 < 0.10 < 0.10 43.70 average 0.66 0.10 0.14 0.14 0.32 54.74 0.10 < 0.10 <0.10 <0.10 43.80 g eo lo gi a c ro at ic a geologia croatica 74/116 includes lower cretaceous radiolarite­bearing deep­sea sedi­ ments and continues with upper cretaceous pelagic and turbidite deposits (neumann & zacher, 2004). this study reveals that the calciturbidites of the babadağ formation include cream­grey­pink calcilutite­calcisiltite, calca­ renite and calcirudite (smf 3, 4, 5, 6, 8) with chert lenses in vary­ ing ratios. they were predominantly deposited on the slope (fz­ 4) to deep sea (fz­1) environment. the highest percentage of the calcilutite (smf 3) was determined in the yangı section that pos­ sibly shows the deepest depositional environment of the babadağ formation. calcilutite­calcisiltite­calcarenite alternations with variable ratio in other sections indicate the impacts of local fac­ tors (sediment input, feeder mechanisms from the shelf part of the platform) in different parts of the platform. planktonic fora­ minifera­bearing calcilutite requires the lowest sediment input and deposition from suspension, sand­gravel size fragments de­ rived from the shelf margin led to the formation of calcarenite and calcirudite. the highest proportion of calcirudite at bozbu­ run hill may be linked with the closeness of the depositional en­ vironment to rudist buildups along the shelf margin. the findings of the xrd, xrf, sem­eds and petrographic studies indicate the presence of calcite and quartz minerals in the samples. robertson & dixon (1996), robertson & mountrakis (2006), vachard & moix (2011) and seve­ ral other previous studies suggested that the calciturbidites were deposited on the carbonate platform, continental slope and deep­ sea environment. detritus from the shelf included mainly calcite shelled organic buildups on the shelf margin. thus, the sources of the calciturbidite were similar in chemical composition (domi­ nantly caco3), with varying size (clay to gravel). the inverse relationship between si and ca is possibly due to silicification processes during diagenesis (figs. 12, 13; table 1). the presence of calcite in the mineral compositions and ca in the bulk chemi­ cal composition of the chert bands and lenses indicates that the silicification process was not completed. similarly, silica in cal­ citurbidites reveals incomplete silicification processes. based on petrographic observations, gül (2015) suggested that the quartz replacement with calcite happens without any size change. the size of the calcite minerals influences the growth of chert (fig. 9). in figure 9a, the replacement of clay­silt sized calcite by equal size quartz led to forming, porcelainous, microcrystalline chert; while in figure 9b small­medium sized quartz substitutes calcite. moreover, rhombohedral dolomite crystals were detected in fi­ gure 9a. similar observations were also reported by gül (2015) who determined diagenetic effects such as dolomitization, sub­ stitution­replacement, and silicification in the units based on pe­ trographic studies. 5.2. factors controlling sedimentation the main controlling factors on the deep­sea sediments includ­ ing calciturbidites are tectonic activity, sea­level fluctuation, ba­ sin morphology­geometry, sediment input, water chemistry, cur­ rents, continental slope height­gradient, organic activities, climate changes, etc. (everts, 1991; reading, 1991; rei­ jmer et al., 1991; haughton, 1994; richards et al., 1998; haughton, 2000; eschard & joseph, 2002; lomas & joseph, 2004; dewever et al., 2007; reijmer et al., 2008, 2012; garciacaro et al., 2011; gül et al., 2012; rubert et al., 2012; hairabian et al., 2015; reijmer et al., 2015a, 2015b). these factors may vary from region to region. for exam­ ple; the main tectonic activities and related sea floor morphology control the sediment input and sediment quantity and thus gra­ vity­flow deposits in the southern provence basin (se france) (reijmer et al., 1991; savary et al., 2004; reijmer et al., 2015b). moreover, a few cm thick calciturbidite layers at the base of the lower cretaceous cherty limestones in slovakia in the middle of the western carpathians are associated with small­ scale seismic activity (michalik et al., 2012). additionally, linear source formation, asymmetric geometry of base topogra­ phy and facies differences of the jurassic units in the eastern al­ pine­swiss were attributed to a boundary fault (eberli, 1987). the calciturbiditic pliensbachian (lower jurassic)­upper creta­ ceous series of the lycian nappes were interpreted as reflecting the passive continental margin period after the syn­rift period (moix et al., 2013). sea level changes were responsible for ex­ cess sediment input and calciturbidite formation in the bahamas during the pleistocene (reijmer et al., 2008, 2015a). variations in the turbidity flow regime led to the development of lithologi­ cally different units such as mudstone­wackestone, sorted or packed biomicrite­packstone etc. (dewever et al., 2007). several factors account for the deposition of the calciturbidi­ tes in the study area. notable factors among these are discussed below. 5.2.1. tectonism and depositional basin geometry tectonism controls the morphology­geometry of the sea floor, the amount of sediment supply, palaeocurrent direction, entry point of the sediments, sediment quantity, internal structure of the sediments including slumps and flow characteristics (energy, velocity etc. thus facies type) (bouma, 2004; gül et al., 2012; baumgartner, 2013). the depositional environments of the babadağ formation were interpreted as continental slope, and related platform mar­ gin­shelf margin and deep water (şenel et al., 1994; şenel, 1997a, 1997b, 1997c; collins & robertson, 1998, 1999; gül, 2015; soycan et al., 2015; sari, 2017; fig. 10). seismic activities and/or sea level fluctuation triggered the destabilisation of sediments on the shelf­platform margin areas before the nappe formation and led to the formation of coarse­grain sediments (cal­ cirudite and calcarenite) on the continental slope and toe of slope (gül et al., 2012, 2013; gül, 2015). alternatively, tectonically quiet periods were represented by calcilutite layers. moreover, an internal deformation (undulating bedding, slumps) of the sedi­ ments characterized the continental slope environment. calcite­ figure 13. cao versus sio2 plot showing the inverse variation due to replacement processes during the diagenesis. g eologia c roatica kore et al.: lithostratigraphy and sedimentological characteristics of the calciturbidites of the babadağ formation-tavas nappe (sw turkey) 17 filled joints, folding, faulting, and nappe formation – fragmenta­ tion of the original carbonate platform was also related to tectonic activities during and after the lycian nappe migration. 5.2.2. sea level fluctuations and sea depth sea level fluctuation and related sea depth control the transporta­ tion and deposition of deep­sea sediments (boggs, 1987; reading, 1991; gürbüz, 1999; gervais et al., 2004; rei­ jmer et al., 2008; gül et al., 2011, 2012, 2015; soycan et al., 2009, 2011, 2015). sea level fluctuations cause destabilization of sediment on the shelf edge and on the continental slope (gür­ büz, 1999; gervais et al., 2004). gül et al. (2012) proposed that large scale­regional and/or possibly global sea level changes control depocenter development and large­scale sediment differe­ ntiation, moreover small­scale variation of sea level was possibly due to local tectonic activities that led to the facies variations of the babadağ formation. the standard micro facies (smf) changes and related facies zone (fz) changes indicate that the four main depositional environments were ‘slope, toe of slope, deep shelf, deep sea water basin – fz 4­3­2­1’ (fig. 10). sea­level fluctuations due to regional uplift and subsidence of the basin may be responsible for these environmental transitions. the falling stage and/or tectonically active period in association with excess sediment input caused the coarse­grained calcirudite­calcarenite level in the babadağ section to represent deposition on slope­ slope front environments (fz­3­4; fig. 10). subsequent plank­ tonic foraminifera bearing calcilutite levels were interpreted as a product of the highstand period, low energy level, and quiet deep­ sea environment (fz­1­2; fig. 10) conditions. 5.2.3. sediment input and sediment type (nature of the source area) sediment entry, sediment type and sediment quantity have af­ fected the deep­sea sediment characteristics, including geometry and facies differentiation, such as single or multiple­sourced sub­ marine fans, coarse grained­sand rich turbidite systems and a fine grained­mud rich turbidite system depending on depocenter (richards et al., 1998; gürbüz, 1999; bouma, 2004; gervais et al., 2004; garciacaro et al., 2011; gül et al., 2011, 2012, 2015). calcarenite­calcirudite levels of the babadağ formation were formed as a result of the sediments derived from the shelf includ­ ing rudist buildups. the fragments of these initially accumulated on the shelf margin and tectonic activity/sea level lowering trig­ gered destabilization and downslope movement. the calcirudite­ calcarenite (unsorted biomicrite­sparite or floatstone­rudstone) deposited on the slope and toe of slope (fz 4, 3) depended on ex­ cess sediment input and a short transportation distance. generally, 3­5 cm thick calcarenite and calcirudite levels were defined in the babadağ, karadon and yangı sections, while field observations during this study and gül et al. (2013) and gül (2015) docu­ mented 30 cm­2 m thick calcirudite levels in the bozburun hill area, representing excess sediment input and/or close proximity to the source area. the ophiolite belts in the eastern mediterra­ nean including the neotethyan oceans evolved from the jurassic to the cretaceous (şengör & yilmaz, 1981; şengör et al., 1984; robertson, 2002; aldanmaz et al., 2009). the em­ placement age of the ophiolite was reported as late cretaceous (aldanmaz et al., 2009). enrichment in fe­al­na in the yangı section should be linked with the mafic­ultramafic ophiolitic rocks of the lycian nappes. local sediment input from the ophiolites to the original depositional environment may have resulted in these higher values in the elemental compositions of the samples from the yangı section (kore & gül, 2017; kore, 2018). silicification during and after lithification led to the forma­ tion of chert nodule­bands (gül et al., 2013; gül, 2015; sari 2017). gül (2015) used petrographic results to explain this pro­ cess. he reported that chert horizons were mostly observed with the calcarenite­calcirudite level on bozburun hill. in addition, he also documented that porcelainous microcrystalline quartz formed as a result of the replacement of calcilutite, chalcedony type quartz minerals were developed depending on the substitu­ tion of large calcite minerals such as rudist fragments. elemental analysis clearly indicates the replacement between the si and ca elements via the inverse proportions of these two elements (kore & gül, 2017; kore, 2018). silicification slightly pene­ trated into the calciturbidites at lower and upper part of the chert bands (gül, 2015). furthermore, lateral continuation of the chert bands and lenses is limited over a short distance. the long­ est chert bed reported by gül (2015) is 35 m in the bozburun hill area. it is thought that the formation of chert depends on the circulation and amount of silica­rich water that penetrated the calciturbidites. thus the permeability and porosity of the host rock (calciturbidites) were to become important factors control­ ling the silica rich water circulation. thus, it is anticipated that more chert formation occurred in the calcarenites and calciru­ dites as in the bozburun hill, babadağ­1 section, babadağ­2 sec­ tion, karadon­1 section, and karadon­2 section (fig. 4). in addi­ tion, if the chert beds were deposited syn­sedimentary and alternated with the calciturbidites, long and more regular chert beds could be traced. however, the irregular and short chert oc­ currences of the babadağ formation suggest that they evolved during diagenesis of the calciturbidite via quartz replacing cal­ cite. in addition to these, post­sedimentary diagenetic activities can also be traced by rhombohedral dolomite formations within the cracks already filled by calcites that cut both calciturbidites and cherts. this study reveals that an investigation on the distant nappe unit that is mapped under the same name, should supply the in­ formation about the original depositional environment. detailed analysis of each nappe slice is useful for determining the local controlling factors on deposition besides the general trend con­ firmation. other important issues related to calciturbidite depo­ sition are that they are generally affected by tectonic activities and the depth of the basin. local sediment type­size­quantity may lead to coarse­grain deposition. calciturbidites play an ac­ tive role during diagenesis, and also open pathways for chemi­ cally active liquids through which they can move easily leading to the formation of chert bands and lenses as observed in the study area. 6. conclusions this study documents the compositional changes, and discusses the factors controlling the deposition and sedimentological chara­ cteristics of the calciturbidites of the babadağ formation of the tavas nappe in muğla (sw turkey). with the help of field obser­ vations and many analytical methods, the following conclusions are drawn: the studied calciturbidites comprise mainly calcilutite – cal­ cisiltite, and calcarenite­calcirudite in a small amount depending on the environmental conditions. calcarenite and calcirudite oc­ currences represent deposition on the slope or toe of slope; how­ ever, the predominance of calcilutite points to deposition in deep shelf and deep sea environments. planktonic foraminifera­bearing, micritic calcilutites were deposited in the deep marine­deep shelf­toe of slope environ­ g eo lo gi a c ro at ic a geologia croatica 74/118 ments. mostly rudist fragment­bearing, locally slumped­undu­ lating bedded­deformed calcarenites and to a lesser extent cal­ cirudites were deposited in the slope environment. detailed analysis of each nappe slice belonging to the same nappe unit not only provides general information on the environ­ ment and lithology, but also indicates local factors including lo­ cal sediment input etc. tectonism and sea­level fluctuations are determined as the main controlling factors on deposition of the babadağ formation. steady, tectonically quiet periods, low sediment input and the ab­ sence of gravity flows resulted in the deposition of calcilutite­ micritic sediments. subsequently, sea­level lowering, tectonically active periods (uplift) and excess sediment input led to the deve­ lopment of calcarenite­calcirudite levels. changes of the control­ ling factors over time triggered the repetition of formation of the fine­grained and coarse­grained calciturbidites. sediment grain size played an important role during diage­ netic stages. the coarse­grained calciturbidite supply provided a suitable pathway for si enrichment water circulation and there­ fore chert or dolomite formation. calcite and quartz were observed as the major mineral com­ ponents in the samples. both sem­eds and xrf analysis show the inverse variation between cao and sio2 due to replacement during diagenesis. excess silica replacement especially was gene­ rally observed in calcarenite­calcirudite levels which, in turn, led to formation of the chert bands/lenses. all chert bands con­ tain a negligible amount of calcite which is due to the incomplete silicification process. moreover, the si content of pure calcitur­ bidite samples either above or below the chert level shows the diffusive characteristics of the si­enriched water. acknowledgement this study was financially supported by the scientific research projects office (bap; project no. 17/118) of muğla sıtkı koçman university, turkey for the m.sc. thesis of the first author. the au­ thors would like to acknowledge the valuable contributions of the anonymous reviewers and editors. references aldanmaz, e., schmidt, m.w., gourgaud, a. & meisel, t. (2009): mid­ ocean ridge and supra­subduction geochemical signatures in spinel­peridotites from the neotethyan ophiolites in sw turkey: implications for upper mantle melting processes.– lithos, 113, 691–708. doi: 10.1016/j.lithos.2009.03.010 baumgartner, p.o. (2013): mesozoic radiolarites – accumulation as a function of sea surface fertility on tethyan margins and in ocean basins.– sedimentology, 60, 292–318. doi: 10.1111/sed.12022 behl, r.j. (2011): chert spheroids of the monterey formation, california (usa): early ­ ­diagenetic structures of bedded siliceous deposits.– sedimentology, 58, 325–351. doi: 10.1111/j.1365­3091.2010.01165.x boggs, s.jr. (1987): principles of sedimentology and stratigraphy.– macmillan pub­ lishing company, new york, usa, 771 p. bouma, a.h. (2004): key controls on the characteristics of turbidite systems.– in: lo­ mas, s.a. & joseph, p. (eds.): confined turbidite systems.– geological society, london, special publications, 222, 9–23. doi: 10.1144/gsl.sp.2004.222.01.02 bozkurt, e. (2001): late alpine evolution of the central menderes massif, western turkey.– int. j. earth sciences, 89, 728–744. doi: 10.1007/s005310000141 bozkurt, e. (2004): granitoid rocks of the southern menderes massif (southwestern turkey): field evidence for tertiary magmatism in an extensional shear zone.– int. j. earth sciences, 93, 52–71. doi: 10.1007/s00531­003­0369­0 brunn, j.h., dumont, j.f., graciansky, p., gutnic, m., juteau, t., mar­ coux, j., monod, o. & poisson, a. (1971): outline of the geology of the western taurids.– geology and history of turkey, 225, 17 p. candan, o., dora, o.ö., oberhänsli, r., çetinkaplan, m., partzsch, j.h., warkus, f.c. & dürr, s. (2001): pan­african high­pressure metamor­ phism in the precambrian basement of the menderes massif, western anatolia, tur­ key.– int. j. earth sci., 89/4, 793–811. clift, p.d. & robertson, a.h.f. (1990): a cretaceous neo­tethyan carbonate mar­ gin in argolis southern greece.– geological magazine, 127, 299–308. doi: 10.1017/ s0016756800014862. collins, a.s. & robertson, a.h.f. (1998): processes of late cretaceous to late miocene episodic thrust­sheet translation in the lycian taurides, sw turkey.– jour­ nal of the geological society, london, 155, 759–772. doi: 10.1144/gsjgs.155.5.0759 collins, a.s. & robertson, a.h.f. (1999): evolution of the lycian allochthonous, western turkey, as a north­facing late palaeozoic to mesozoic rift and passive con­ tinental margin.– geological journal, 34, 107–138. collins, a.s. & robertson, a.h.f. (2003): kinematic evidence for late meso­ zoic–miocene emplacement of the lycian allochthonous over the western ana­ tolide belt, sw turkey.– geological journal, 38, 295–310. danelian, t., robertson, a.h.f., collins, a.s. & poisson, a. (2006): bio­ chronology of jurassic and early cretaceous radiolarites from the lycian mélange (sw turkey) and implications for the evolution of the northern neotethyan ocean.– in: robertson, a.h.f. & mountrakis, d. (eds.): tectonic development of the eastern mediterranean region. geological society, london, special publica­ tions, 260, 229–237. doi: 10.1144/gsl.sp.2006.260.01.10 dewever, b., breesch, l., mezini, a. & swennen, r. (2007): sedimentologi­ cal and marine eogenetic control on porosity distribution in upper cretaceous car­ bonate turbidites (central albania).– sedimentology, 54, 243–264. doi: 10.1111/ j.1365­3091.2006.00833.x dora, o.ö. (2007): menderes masifi’ndeki jeolojik araştırmaların tarihsel gelişimi [historical development of geologic research of the menderes massive – in turk­ ish].– menderes masifi kollukyumu (menderes massive colluquim), 1–7. dunham, r.j. (1962): classification of carbonate rocks according to a depositional tex­ ture.– aapg memoir, 1, 108–121. eberli, g.p. (1987): carbonate turbidite sequences deposited in rift­basins of the juras­ sic tethys ocean (eastern alps, switzerland).– sedimentology, 34, 363–388. doi: 10.1111/j.1365­3091.1987.tb00576.x eberli, g.p. (1991): calcareous turbidites and their relationship to sea­level fluctuations and tectonism.– cycles and events in stratigraphy, 340–359. embry, a.f. & klovan, e. (1971): a late devonian reef tract on northeastern banks island, northwest territories.– can. petrol. geology bull, 19, 730–781. erakman, b., meshur, m., gül, m.a., alkan, h., öztaş, y. & akpinar, m. (1982): report of the geology and hydrocarbon potential of the kalkan­köycegiz­ cameli­tefenni area depending on the taurus project.– turkey petroleum corpo­ ration (tpc) rep, ankara (in turkish, unpublished), 1732 p. ersoy, ş. (1990): the analysis of evolution and structural items of the western taurus ­ lycia ­ nappes (batı toroslar­likya naplarının yapısal birimleri ve evrimsel ana­ lizi).– jeoloji mühendisliği dergisi (geological engineering) (in turkish), 37, 5–16. ersoy, ş. (1991): stratigraphy and tectonics of the datça (muğla) peninsula (datça yarımadasının stratigrafisi ve jeolojisi).– türkiye jeoloji bülteni (geological bul­ letin of turkey) (in turkish), 34/2, 1–14. eschard, r. & joseph, p. (2002): comparisons of reservoir architecture in a high transport efficiency basin floor fan (pab sandstone, pakistan) and in a confined tur­ bidite system (annot sandstone, france) from outcrop models.– aapg annual meeting, houston, texas, usa. everts, a.j.w. (1991): interpreting compositional variations of calciturbidites in rela­ tion to platform­stratigraphy: an example from the paleogene of se spain.– sedi­ mentary geology, 71, 231–242. doi: 10.1016/0037­0738(91)90104­l flügel, e. (2004): microfacies of carbonate rocks. analysis, interpretation and ap­ plication.– berlin, heidelberg, new york: springer­verlag, 976 p. folk, r.l. (1962): spectral subdivision of limestone types.– in: ham, w.e. (ed.): clas­ sification of carbonate rocks. am. ass. petrol. geologists mem., 1, 62–84. folk, r.l. (1980): petrology of sedimentary rocks (pdf).– austin (texas), hemphill. garciacaro, e., mann, p. & escalona, a. (2011): regional structure and tec­ tonic history of the obliquely colliding columbus foreland basin, offshore trinidad and venezuela.– marine and petroleum geology, 28, 126–148. doi: 10.1016/j.mar­ petgeo.2009.08.016 gervais, a., savoye, b., piper, d.j.w., mulder, t., cremer, m. & pichevin, l. (2004): present morphology and depositional architecture of a sandy confined submarine system: the golo turbidite system, eastern margin of corsica.– in: lo­ mas, s.a. & joseph, p. (eds.): confined turbidite systems. geological society, london, special publications, 222, 59–91. doi: 10.1144/gsl.sp.2004.222.01.05 göncüoğlu, m.c. (2011): geology of the kütahya­bolkardağ belt.– maden tetkik ve arama dergisi (bulletin of the mineral research and exploration), 142, 223–277. grabaua, w. (1904): on the classification of sedimentary rocks.– am. geologist, 33, 228–247. graciansky, p.c. de, lemoine, m., lys, m. & sigal, j. (1967): güney anadolu silsilesinin (fethiye kuzeyi) batı ucundaki üst paleozoik ve mesozoikte strati­ grafik bir kesit [a stratigraphic section in upper paleozoic and mesozoic at the western end of the southern anatolian range (north of fethiye) – in turkish].– maden tetkik ve arama dergisi (bulletin of the mineral research and exploration), 69, 11–32. https://repositories.lib.utexas.edu/handle/2152/22930 g eologia c roatica kore et al.: lithostratigraphy and sedimentological characteristics of the calciturbidites of the babadağ formation-tavas nappe (sw turkey) 19 graciansky, p.c. de. (1968): stratigraphie des unités superposées dans le taurus ly­ cien et place dans l’arc dinaro–taurique.– maden tetkik ve arama dergisi (bulletin of the mineral research and exploration), 71, 42–62. gül, m., gürbüz, k. & cronin, b.t. (2011): provenance of the northern part of the kahramanmaraş peripheral foreland basin (miocene, s turkey).– journal of asian earth science, 40/2, 475–495. doi: 10.1016/j.jseaes.2010.09.012 gül, m., cronin, b.t. & gürbüz, k. (2012): confined deep water system develo­ pment on the accretionary wedge (miocene, kahramanmaras foreland basin, s turkey).– earth­science reviews, 114/3–4, 195–217. doi: 10.1016/j.earscirev.2012. 06.002 gül, m., aksoy, m.e., akçer, s., avsar, ö. & avsar, u. (2013): the lithologi­ cal characteristics of the chert limestone and calciturbidites of the babadağ forma­ tion (jurassic­cretaceous tavas nappe, ortaca, mugla, sw turkey).– 66th turkish geological congress, ankara (in turkish with english abstract), 375 p. gül, m. (2015): occurrences of chert in jurassic­cretaceous calciturbidites (sw tur­ key).– open geosciences, 7, 446–464. doi: 10.1515/geo­2015­0029 gül, m., gürbüz, k., & cronin, b.t. (2015): irregular plate boundary controls on foreland basin sedimentation (miocene, kahramanmaras).– journal of asian earth science, 111, 804–818. doi: 10.1016/j.jseaes.2015.07.018 gürbüz, k. (1999): regional implications of structural and eustatic controls in the evo­ lution of submarine fans: an example from the miocene adana basin, southern turkey.– geological magazine, 136/3, 311–319. doi: 10.1017/s0016756899002617 haas, j., götz, a.e. & pálfy, j. (2010): late triassic to early jurassic palaeogeog­ raphy and eustatic history in the nw tethyan realm: new insights from sedimen­ tary and organic facies of the csővár basin (hungary).– palaeogeography, palaeo­ climatology, palaeoecology, 291, 456–468. doi: 10.1016/j.palaeo.2010.03.014 hairabian, a., borgomano, j., masse, j.p. & nardon, s. (2015): 3­d strati­ graphic architecture, sedimentary processes and controlling factors of cretaceous deep­water resedimented carbonates (gargano peninsula, se italy).– sedimentary geology, 317, 116–136. doi: 10.1016/j.sedgeo.2014.11.001 haughton, p.d.w. (1994): deposits of deflected and ponded turbidity currents, sor­ bas basin, southeastern spain.– journal of sedimentary research, 64, 223–246. haughton, p.d.w. (2000): evolving turbidite systems on a deforming basin floor, ta­ bernas, se spain.– sedimentology, 47, 497–518. doi: 10.1046/j.1365­3091.2000.00293.x koç, h., tasli, k. & özer, e. (2016): bolkar dağları ve aladağlar’daki (orta­doğu toroslar) ofiyolitik melanjla i̇lişkili türbiditik i̇stiflerin yaşı ve paleo­tektonik yorumu [age and paleo-tectonic interpretation of turbiditic sequences associated with ophiolitic melange in bolkar mountains and aladağlar (middle-eastern taurus) – in turkish].– türkiye bilimsel ve teknolojik araştırma kurumu (tubi̇tak) (the scientific and technological research council of turkey), proj­ ect no: 112y362. konak, n. (2003): menderes masifinin güneydoğusundaki naplı yapılar [nappe structures in the southeast of the menderes massif – in turkish].– 56. türkiye jeoloji kurultayı (56. geological congress of turkey), 304–306. kore, m.b. & gül, m. (2017): tavas napı üst kretase kalsitürbiditlerinin sediman­ tolojik özellikleri, bileşimsel değişimleri ve çökelimini kontrol eden faktörler [sedimantological properties, compositional changes and controlling factors of sedimentation of tavas nappe upper cretaceous calciturbidites – in turkish].– muğla sıtkı koçman university vi. science research symposium) muğla­turkey, 47 p. kore, m.b. (2018): compositional changes, controlling factors in sedimentation and sedimentological characteristics of upper cretaceous aged calciturbidite of tavas nappe, (lycian nappes, muğla, sw turkey).– mugla sıtkı koçman university, institute of natural and applied sciences, msc thesis, 121 p. kozur, h.w. (1998): the age of the siliciclastic series (karareis formation) of the west­ ern karaburun peninsula, western turkey.– paleontologia polonica, 58, 171–189. kozur, h.w., şenel, m. & teki̇n, k. (1998): first evidence of hercynian lower carboniferous flyschoid deep­water sediments in the lycian nappes, southwestern turkey.– geologia croatica, 51/1, 15–22. le goff, j., cerepi, a., swennen, r., loisy, c., caron, m., muska, k. & el desouky, h. (2015): contribution to the understanding of the ionian basin sed­ imentary evolution along the eastern edge of apulia during the late cretaceous in albania.– sedimentary geology, 317, 87–101. doi: 10.1016/j.sedgeo.2014.09.003 lomas, s.a. & joseph, p. (2004): confined turbidite systems.– geological society london special publication, 222, 1–7. doi: 10.1144/gsl.sp.2004.222.01.01 mcbride, e.f., abdel­wahab, a. & el­younsy, a.r.m., (1999): origin of sphe­ roidal chert nodules, drunka formation (lower eocene), egypt.– sedimentology, 46, 733–755. doi: 10.1046/j.1365­3091.1999.00253.x michalík, j., lintnerová, o., reháková, d., boorová, d. & simo, v. (2012): early cretaceous sedimentary evolution of a pelagic basin margin (the manín unit, central western carpathians, slovakia).– cretaceous research, 38, 68–79. doi: 10.1016/j.cretres.2012.02.006 moix, p., vachard, d., allibon, j., martini, r., wernli, r., kozur, h.w. & stampfli, g.m. (2013): palaeotethyan, neotethyan and huğlu­pindos series in the lycian nappes (sw turkey): geodynamical implications.– in: tanner, l.h., spielmann, j.a. & lucas, s.g. (eds.): the triassic system. new mexi­ co museum of natural history and science bulletin, 61, 401–444. neumann, p. & zacher, w. (2004): the cretaceous sedimentary history of the pin­ dos basin (greece).– int. j. of earth sciences (geol rundsch), 93, 119–131. doi: 10.1007/s00531­003­0358­3 okay, a. (1989): denizli güneyinde menderes masifi ve likya naplarının jeolojisi [geology of menderes massif and lycian nappes in south of denizli – in turkish].– maden tetkik ve arama dergisi (bulletin of the mineral research and exploration), 109, 45–58. okay, a. (2001): stratigraphic and metamorphic inversions in the central menderes mas­ sif: a new structural model.– int. j. of earth sciences, 89, 709–727. doi: 10.1007/ s005310000098 özcan, z., okay, a.i., özcan, e., hakyemez, a. & özkan­altiner, s. (2012): late cretaceous–eocene geological evolution of the pontides based on new stratigraphic and palaeontologic data between the black sea coast and bur­ sa (nw turkey).– turkish journal of earth sciences, (turkish j. earth sci.), 21, 933–960. payros, a. & pujalte, v. (2008): calciclastic submarine fans: an integrated over­ view.– earth­science reviews, 86/1–4, 203–246. doi: 10.1016/j.earscirev. 2007.09.001 poisson, a. (1977): recherches géologiques dans les taurides occidentals (turquie).– ph.d. thesis, paris­sud (centre d’orsay), paris, 795 p. price, i. (1977): deposition and derivation of clastic carbonates on a mesozoic conti­ nental margin, othris, greece.– sedimentology, 24, 529–546. doi: 10.1111/j. 1365­ 3091.1977.tb00137.x reading, h.g. (1991): the classification of deep­sea depositional systems by sediment calibre and feeders system.– journal of geological society of london, 148, 427–430. reijmer, j.j.g., ten kate, w.g.h.z., sprenger, a. & schlager, w. (1991): calciturbidite composition related to exposure and flooding of a carbonate platform (triassic eastern alps).– sedimentology, 38, 1059–1074. doi: 10.1111/j. 1365­ 3091.1991.tb00371.x reijmer, j.j.g., palmieri, p., floquet, m., kerkvliet, s. & groen, r. (2008): carbonate turbidites and debris flows: sea­level variations versus tectonic processes.– international geological congress, oslo, hps­12 new developments in stratigraphic classification. reijmer, j.j.g., palmieri, p. & groen, r. (2012): compositional variations in cal­ citurbidites and calcidebrites in response to sea­level fluctuations (exuma sound, bahamas).– facies, 58, 493–507. doi: 10.1007/s10347­011­0291­z reijmer, j.j.g., mulder, t. & borgomano, j. (2015a): carbonate slopes and gravity deposits.– sedimentary geology, 317, 1–8. doi: 10.1016/j.sedgeo. 2014.12.001 reijmer, j.j.g., palmieri, p., groen, r. & floquet, m. (2015b): calciturbidites and calcidebrites: sea­level variations or tectonic processes.– sedimentary geolo­ gy, 317, 53–70. doi: 10.1016/j.sedgeo.2014.10.013 richards, m., bowman, m. & reading, h.g. (1998): submarine­fan system i: characterization and stratigraphic prediction.– marine and petroleum geology, 15, 689–717. doi: 10.1016/s0264­8172(98)00036­1 robertson, a.h.f. & woodcock, n.h. (1981): alakir çay group, antalya com­ plex, sw turkey: a deformed mesozoic carbonate margin.– sedimentary geology, 1/2, 95–131. doi: 10.1016/0037­0738(81)90015­4 robertson, a.h.f. & dixon, j.e. (1996): introduction to aspects of the geological evolution of the eastern mediterranean.– in: dixon, j.e. & robertson, a.h.f. (eds.): the geological evolution of the eastern mediterranean. geological society special publication, 17, 1–75. doi: 10.1144/gsl.sp.1984.017.01.02 robertson, a.h.f. (2000): mesozoic–cenozoic tectonic­sedimentary evolution of a south tethyan oceanic basin and its margins in southern turkey.– in: bozkurt, e., winchester, j.a. & wiper, j.d.a. (eds.): tectonics and magmatism in turkey and the surrounding area. geological society, london, special publication, 173, 97–138. robertson, a.h.f. (2002): overview of the genesis and emplacement of mesozoic ophiolites in the eastern mediterranean tethyan region.– lithos, 65, 1–67. doi: 10.1016/s0024­4937(02)00160­3 robertson, a.h.f. & mountrakis, d. (2006): tectonic development of the east­ ern mediterranean region: an introduction.– in: robertson, a.h.f. & moun­ trakis, d. (eds.): tectonic development of the eastern mediterranean region. geological society, london, special publications, 260, 1–11. doi: 10.1144/gsl. sp.2006.260.01.01 rubert, y., jati, m., loisy, c., cerepi, a., foto, g. & muska, k. (2012): sedi­ mentology of resedimented carbonates facies and geometrical characterisation of an upper cretaceous calciturbidite system in albania.– sedimentary geology, 257, 63–77. doi: 10.1016/j.sedgeo.2012.02.009 saller, a., ball, b., robertson, s., mcpherson, b., wene, c., nims, r. & gogas, j. (2001): reservoir characteristics of devonian cherts and their control on oil recovery: dollarhide field, west texas.– aapg bull., 85, 35–50. g eo lo gi a c ro at ic a geologia croatica 74/120 şenel, m., akdeni̇z, n., öztürk, e.m., özdemi̇r, t., kadinkiz, g., meti̇n, y., öcal, h., serdaroğlu, m. & örçen, s. (1994): fethiye (muğla)­kalkan (antalya) ve kuzeyinin jeolojisi [geology of fethiye (muğla)-kalkan (antalya) and the north – in turkish, unpublished].– general directorate of mineral research and exploration (mta), ankara, rep. no: 976:121 p. şenel, m. (1997a): 1 / 100 000 ölçekli türkiye jeoloji haritaları, no:1, fethiye – l7 paftası [1 / 100 000 scaled geological map of turkey, no. 1, fethiye l7 sheet – in turkish, unpublished].– general directorate of mineral research and exploration (mta), 17 p. şenel, m. (1997b): 1 / 100 000 ölçekli türkiye jeoloji haritaları, no:1, fethiye – l8 paftası [1 / 100 000 scaled geological map of turkey, no. 1, fethiye – l8 sheet – in turkish, unpublished].– general directorate of mineral research and exploration (mta), 22p. şenel, m. (1997c): 1 / 100 000 ölçekli türkiye jeoloji haritaları, no:1, fethiye – l9 paftası [1 / 100 000 scaled geological map of turkey, no. 1, fethiye – l9 sheet – in turkish, unpublished].– general directorate of mineral research and exploration (mta), 20 p. şenel, m., dalkiliç, h., gedik, i̇., serdaroğlu, m., meti̇n, s., esentürk, k., bölükbaşi, a.s. & özgül, n. (1998): orta toroslar’da güzelsu kori­ doru ve kuzeyinin jeolojisi [geology of güzelsu corridor and north in the middle taurus – in turkish].– maden tetkik ve arama dergisi (bulletin of the mineral research and exploration), 120, 171–197. şenel, m. (2004): stratigraphic and structural features of the yeşilbarak nappe in west­ ern taurus range and its comparison with the similar units in se anatolia and north cyprus.– maden tetkik ve arama dergisi (bulletin of the mineral research and exploration ) (in turkish), 128, 1–26. şenel, m. (2007): likya naplarının özellikleri ve evrimi (characteristic features of the lycian nappes and their evolution).– menderes masifi kolukyumu (colluqi­ um on menderes massif), 51–55. şengör, a.m.c. & yilmaz, y. (1981): tethyan evolution of turkey: a plate tectonic approach.– tectonophysics, 75, 181–241. doi: 10.1016/0040­1951(81)90275­4 şengör, a.m.c., satir, m. & akkök, r. (1984): timing of tectonic events in the menderes massif, western turkey: implications for tectonic evolution and evidence for pan‐african basement in turkey.– tectonics, 3/7, 693–707. doi: 10.1029/ tc003i007p00693 tekeli̇, o. (1984): geology of the taurus belt.– in: tekeli̇, o. & göncüoğlu, c. (eds.): proceedings of the international symposium geology of the taurus belt. maden tetkik ve arama enstitüsü (general directorate of mineral and research and exploration), ankara­turkey, 342 p. udden, j.a. (1914): mechanical composition of clastic sediments.– geological society of america bulletin, 25/1, 655–744. doi: 10.1130/gsab­25­655 vacek, f. (2007): carbonate microfacies and depositional environments of the silurian – devonian boundary strata in the barrandian area (czech republic).– geologi ca carpathica, 58/6, 497–510. vachard, d. & moix, p. (2011): late pennsylvanian to middle permian revised algal and foraminiferan biostratigraphy and palaeobiogeography of the lycian nappes (sw turkey): palaeogeographic implications.– revue de micropaléontologie, 54, 141–174. doi: 10.1016/j.revmic.2011.02.002 watts, k.f. (1987): triassic carbonate submarine fans along the arabian platform mar­ gin, sumeini group, oman.– sedimentology, 34, 43–71. doi: 10.1111/j. 1365­ 3091.1988.tb00904.x wentworth, c.k. (1922): a scale of grade and class terms for clastic sediments.– the journal of geology, 30/5, 377–392. doi: 10.1086/622910 yilmaz, y. (1981): sakarya kıtası güney kenarının tektonik evrimi [the tectonic evolution of the southern edge of the sakarya continent – in turkish].– i̇stanbul yerbil­ imleri (istanbul journal of earth sciences), 1/1–2, 33–52. sari, b. & özer, s. (2001): facies characteristics of the cenomanian­maastrichtian sequence of the beydağları carbonate platform, korkuteli area, western taurides, turkey.– international geology review, 43, 830–839. doi: 10.1080/ 00206810109465050 sari, b. & özer, s. (2002): upper cretaceous stratigraphy of the beydağları carbonate platform, korkuteli area (western taurides, turkey).– turkish journal of earth sci­ ences, 11/1, 39–59. sari, b., steuber, t. & özer, s. (2004): first record of upper turonian rudists (mol­ lusca, hippuritoidea) in the bey dağları carbonate platform, western taurides (tur­ key): taxonomy and strontium isotope stratigraphy of vaccinites praegiganteus (toucas, 1904).– cretaceous research, 25/2, 235–248. sari, b. (2006): upper cretaceous planktonic foraminiferal biostratigraphy of the bey dağları autochthon in the korkuteli area, western taurides, turkey.– journal of foraminiferal research, 36, 241–261. doi: 10.2113/gsjfr.36.3.241 sari, b., kandemi̇r, r., özer, s., walaszczyk, i., görmüş, m., demi̇rcan, h. & yilmaz, c. (2014): upper campanian calciclastic turbidite sequences from the hacımehmet area (eastern pontides, ne turkey) integrated biostratigraphy and microfacies analysis.– acta geologica polonica, 64/4, 393–418. doi: 10.2478/agp­ 2014­0022 sari, b. (2017): lithostratigraphy and planktonic foraminifera of the uppermost creta­ ceous­upper palaeocene strata of the tavas nappe of the lycian nappes (sw tur­ key).– geologia croatica, 70/3, 163–177. doi: 10.4154/gc.2017.14 savary, b., olivero, d. & gaillard, c. (2004): calciturbidite dynamics and en­ dobenthic colonisation: example from a late barremian (early cretaceous) succes­ sion in southeastern france.– palaeogeography, palaeoclimatology, palaeoecology, 211, 221–239. doi: 10.1016/j.palaeo.2004.05.008 skourtsis­coroneou, v., solakius, n. & constantinidis, i. (1995): cre­ taceous stratigraphy of the ionian zone, hellenides, western greece.– cretaceous research, 16, 539–558. doi: 10.1006/cres.1995.1035 sofracioğlu, d. & kandemi̇r, r. (2013): the upper cretaceous calciclastic sub­ marine fan deposits in the eastern pontides, ne turkey: facies architecture and controlling factors.– turkish j. earth sci., 22, 588–610. solak, c., tasli, k. & sari, b. (2015): stratigraphy and depositional history of the cretaceous carbonate successions in the spil mountain (manisa, w turkey).– cre­ taceous research, 53, 1–18. doi: 10.1016/j.cretres.2014.10.008 soycan, h., teki̇n, u.k., erdoğan, k. & konak, n. (2009): aalenian­lower bathonian (middle jurassic) radiolarian faunas from the tavas nappe, denizli, west­ ern turkey: dating of the major drowning event in the tauride platform.– the 12th meeting of the international association of radiolarian paleontologists, china, 257–259. soycan, h., teki̇n, u.k., yilmaz, i̇.ö., erdoğan, k., konak, n. & ocakoğlu, f. (2011): paleoceanographic significance of a platform drowning event in the liassic­early dogger of the tavas nappe, western taurides, sw tur­ key, paleontological and sedimentological approaches.– 64. türkiye jeoloji kurultayı, (64th geological congress of turkey) (in turkish), 262–263. soycan, h., erdoğan, k. & konak, n. (2015): aalenian–early bathonian (mid­ dle jurassic) radiolarian assemblages in the tavas nappe within lycian nappes in the western taurides (sw turkey): the first dating of carbonate platform drown­ ing.– journal of asian earth sciences, 104, 3–21. doi: 10.1016/j.jseaes.2014.08.002 şenel, m., selçuk, h., bi̇lgi̇n, z.r., şen, m.a., karaman, t., erkan, m., di̇nçer, m.a., durukan, e., arbas, a., kaymakçi, h., örçen, s. & bi̇lgi̇n, c. (1989): çameli (denizli) – yeşiiova (burdur) – elmalı (antalya) ve dolayının jeolojisi [geology of çameli (denizli) – yeşiiova (burdur)-elmalı (antalya) and vicinity – in turkish, unpublished].– general directorate of mineral re­ search and exploration (mta), rep. no: 9429. www.geologia-croatica.hr fellow of croatian academy of sciences and arts ivan jurković, professor emeritus of economic geology (ore petro­ logy) and ore microscopy at the faculty of mining­geology­ petroleum engineering, and former rector of university of zagreb (1978­1982), passed away quietly in his home in zagreb, on the 30 december, 2014. he was a founder of modern studies in the field of ore genesis and metallogeny in croatia, and an outstanding lecturer, among the best teaching geology in croatia. professor jurković was born on 27 march, 1917 in ogulin. he attended the elementary school (1923­1927) and the high school there, then the gymnasium, (1927­1935) in zagreb. he obtained his bsc degree in chemistry at the technical faculty in zagreb in 1939, and bsc degree in geology at the philosophical faculty in zagreb in 1942. in 1956 he completed his phd thesis at the technical faculty, university of zagreb, under supervision of the academician luka marić. the title of the thesis was „mineral parageneses in the bosnian schist mountains with special reference to mercury, gold and silver bearing tetrahedrites“. he habilitated in 1957 (veniam docendi thesis) at the faculty of technology in zagreb with the theme „meta­ llogeny of petrova gora mt., sw croatia“ in the framework of the course entitled „ore deposits“ (economic geology). his teaching career began as an assistant at the department of mineralogy and engineering geology at the technical faculty of zagreb university (1939­1942). from 1942 until the end of world war ii in 1945 he volunteered in the same department under prof. miroslav tajder. in the following years he worked continuously in the mineralogical­geological department of the technical faculty, as an assistant (1945­1957), then as assistant professor (docent), 1957­1959, associate professor (1959­1963) and full professor (1963­1987), after which he retired. in 1969 he was elected as a full member of the croatian academy of sciences and arts (former yugoslav academy of arts). he was promoted to the position of rector of zagreb university for 1978­1982, and acted as the president of the parliamentarian council for education, science, culture and sport of republic of croatia between 1982. and 1984. he obtained the honored title of professor emeritus of zagreb university in 2000. geological investigations of prof. jurković cove­ red, beside all republics of the former state, a vast global territory in africa, asia and south america. in the educational, social, and political domains, he undertook many high­ranking duties (see the appendix). his fruitful and productive life, characterized by complete devotion to science and care for the education of many younger generations of geologists, is like a lighthouse beacon to his followers. his inventive and motivating lectures paved the way for many professional geological careers. those who were lucky to have learned from or worked with prof. jurković, including me (lp) as his assistant and co­worker in semi centenary cohabitation, have had a chance to learn honest and strong principles of scientific ethics. he was a firm fighter for his scientific ideas but a fair opponent in arguments without any trace of vanity or vengefulness. he was well­known for his extraordinary appreciation of past and contemporary investigations in the field of interest, so his published papers are the richest source of relevant references and citations. his remarkable scientific career over the century is marvelous example of the freshness of his logic and open­mindedness to new principles of global tecto­ nics, which he successfully applied in the field of ore geology. we feel sorrow for the loss of our teacher who guided and encouraged us in the time when science was not, and still is not, a primary interest in our homeland. the followers of professor ivan jurković also lost an open­hearted and honest critic of our work, and an objective and corrective judge. we give our sincere gratitude for all those moments of simply being and working with him, and promise to keep the human and scientific standards established by this extraordinary personality. in addition to more than 200 scientific papers (almost 90 published internationally) he was also interested in many other human activities. a complete list of his scientific papers was published in the vol. 68/2 of geologia croatica (garašić & durn, 2015). as a memento of his extensive activity in scientific, educational, research and social domain is presented in the appendix of this necrology (part of biography of academician ivan jurković retrieved from croatian academy of sciences and arts info.hazu.hr/upload/file/.../ijurkovic_biography.doc). in memoriam professor emeritus ivan jurković fellow of croatian academy of sciences and arts (27.03.1917-30.12.2014) available online february 29, 2016 doi: 10.4154/gc.2016.13 ladislav palinkaš and vladimir bermanec 170 vol. 69/1 appendix functions in the united nations (undp, n.y.) 29.01.1965.­16.04.1968. on the request of the tunisian government, the office de mines tunisia, united nations (undp) appointed jurković as geologue en chef (expert) of the project “prospection minerale du bassin de la foussana en tunisie centrale” with residence in the town tunis, tunisia. during this period un entrusted him with the inspection of undp project (one month 1966.) titled: “pegmatites and gold­bearing quartz veins in the northern benin“, (ex togo) central africa. in the same year (1966) jurković, with the agreement of un, studied (for three weeks) huge lead­zinc bearing barite deposits in the region of ouida, eastern morocco, on account of comparison with tunisian deposits. during his employment in the united nations jurković utilized his 2 month annual holiday to undertake for free, his educational commitments as professor of zagreb university. employments and functions in the croatian parliament and government 15.05.1947.­11.11.1949. director and chief geologist of the geological institute in the ministry of industry and mining of the croatian government. 11.11.1949.­ 01.05.1951. chief geologist of the ministry of black (fe, mn) and coloured (cu, pb, zn) metallurgy in the yugoslav federal government, belgrade. 1967­1971 member of croatian parliament (sabor) for the communes of ogulin and vrbovsko in the social­political council and in the cultural-educational council. 1968­1978 member of the executive council (iv sabora, croatian government) responsible for science, informatics and technology. 1971­1975 director of the republican fund for scientific investigation and president of the croatian scientific council. 1971­1978 delegate of the croatian government in the fede­ ral committee for science and culture, belgrade. 1978­1982 president of the newly formed parliamentarian council for education, science, culture and sport in the croatian parliament. during all of the aforementioned duties, ivan jurković executed for free, his educational commitments as a professor of zagreb university. honours, decorations, diplomas of honorary memberships, recognitions decorations 2012. orden reda danice hrvatske s likom ruđera boškovića (order of danica hrvatska with the effigy of ruđer bošković) 1987. orden republike hrvatske sa zlatnim vijencem (order of the republic of croatia with golden wreath) 1977. orden zasluga za narod sa zlatnom zvijezdom (order of merits for the people with golden star) 1974. orden republike hrvatske sa srebrnim vijencem (order of the republic of croatia with silver wreath) 1964. orden rada sa zlatnim vijencem (order of labour with golden wreath) 1953. orden rada sa srebrnim vijencem (order of labour with silver wreath) 1948. medalja za zasluge za narod (medal for merits for the people) memberships in hazu (jazu) and anu bih 1963­1969 corresponding working member in the yugoslav academy of sciences and arts (jazu) 1969­1991 ordinary member (academician) of jazu 1991­2012 ordinary member (academician) of croatian academy of sciences and arts (hazu) 1973­2012 corresponding member of bosnian and herzegovian academy of science and arts (anu bih) sarajevo 1969­1972 member of the jazu presidency medals obtained of foreign universities and societies 1988. international committee for studies of bauxites, alumina, al­oxides, residence in hazu, zagreb 1984. kijevskij gosudarstveni univ. t.g. sevčenko, kijev 1984. re­solution given by state of florida, tallahassee 1983. universitatis jagellonica cracoviensis, krakow 1982. universita degli studi di trieste, trst 1981. moskovskij avtomobil­nodoroženij inst., moskva 1981. alma universitatis graecensis­carola francisca, graz 1981. american council on education ­ mcmxviii, wa­ shington 1981. technische universitat, dresden 1981. hamburgische universität, hamburg 1981. universitatis studiorum, freiberg memberships and functions in the foreign and national scientific and professional societies, associations and organizations in foreign countries 2012­1963 member, and from 1988.­1983 president of the international committee for the study of bauxite, alumina and al­oxides (icsoba), zagreb, croatia 2012­1991 and 1976­1968 member of the society for applied geology deposits (sga), residence in prague, czech republic 2012­1991 and 1976­1968 member of the international association on the genesis of the ore deposits, commission of the ore parageneses cpa (iagod) 2000­1993 member of the union of geosciences (eug), strasbourg, france 2000­1997 collaborator of the international biographical center (ibc), cambridge, united kingdom 1989­1988 coordinator of the igc project no 287., unesco, paris; correlation of mesozoic­tertiary bauxites and related paleokarst phenomena in the tethyan realm 171 palinkaš & bermanec: in memoriam professor emeritus ivan jurković (27.03.1917­30.12.2014) 1989­1982 member of the joint yugoslav­american advisory council and academic committee, florida state university, usa 1989­1983 coordinator for the cooperation in natural and technical sciences between florida nad yugoslavia 1985.­1980. member of the administrative board (executive committee) of the international association of the universities, paris, france 1984­1981 member of the executive committee for the cooperation between ace (american council on education) and zuj (union of yugoslav universities) 1974­1971 president of the scientific council of the united nations international center for the enterprises in the public property, ljubljana, slovenia 1978­1974 member of the administrative board of the international center for mechanical sciences (cism), udine, italy 1978­1968 glied der deutschen mineralogische gesellschaft 1974­1971 president of the norvegian­yugoslav friendship society 1972. delegate of the federal geological institute and of the union geological societies at the world congress of petroleum and gas in moscow; 1968. at the geological world congress in prague and in 1964 at the geological world congress in new delhi, india. 1968­1965 „geologue en chef“ of the united nations project in tunisia 1966. adviser to the united nations project in benin (ex­ togo, central africa) education activities education of phd and msc candidates (a) jurković was the mentor of the following phd candidates: boris šinkovec (full professor, faculty of mining, geology and petroleum engineering, researcher in venezuela and tunisia), karlo braun (lecturer at the faculty of organization and informatics, varaždin), josip crnički (assistant professor at the faculty of organization and informatics, varaždin, researcher in tunisia and kenya), božidar zalokar (senior lecturer, faculty of mining, geology and petroleum engineering, un expert in egypt for three years, researcher in myanmar (burma), indonesia, nepal, india), ante ferenčić (un expert in panama for three years, researcher in myanmar (burma), venezuela and ethiopia), dubravko šiftar (assistant professor, faculty of mining, geology and petroleum engineering), ladislav palinkaš (full professor, faculty of mining, geology and petroleum engineering and faculty of science, researcher in indonesia (kalimantan) and kurdistan (iraq), associate member of croatian academy of sciences and arts), mehmed ramović, (member of anu bih, full professor, faculty of science, sarajevo), rade vasiljević (counsellor for geology in belgrade). (b) jurković was the mentor of the following msc candidates: b. šinkovec, d. šiftar, l. palinkaš, b. zalokar, v. podubsky, k. braun, b. šebečić, r. tončić­gregl, d. krkalo, kapusta, pruthi, etc. (c) jurković was the mentor in the education of geologists in the office des mines in tunisia: t. ghozi and h. handous (within the un project from 1965 to 1968). building new research and teaching centres university computing centre (sveučilišni računski centar ­ srce) of the university of zagreb national and university library in zagreb (nacionalna i sveučilišna knjižnica u zagrebu ­ nsk) “bjelolasica ski resort” 30 km west of ogulin in gorski kotar science­educational centre at the island of lokrum near dubrovnik molecular biology centre in the franciscan monastery rožat in gruž near dubrovnik hvar astronomical observatory for observation of the sun scientific activities in the geology of ore deposits realized scientific projects and investigations financed by ministry of science and technology of the croatian government (1993-2012) 1) metallogeny of paleozoic in croatia, western and middle bosnia (no 1­09­050), guide: ivan jurković (1993­1995) 2) magmatism, metamorphism and ore deposits of the dinarides (no 119­393; 1996­2002), guide: ladislav palinkaš 3) geology and metallogeny of the dinarides (2002­2007), guide: jakob pamić (2002­2004) and ivan jurković (2004­ 2007) 4) geochemistry of mineral deposits in the dinarides and their influence on water in karst, guide: ladislav palinkaš (2007­2012) realized scientific projects (1981-2001): 1)1983 bergakademie, freiberg, ddr, theme “erfarhungsaustausch in der erzlagerstättenlehre und in den methoden der wissenschaftlichen bearbeitung der erzlagerstätten, studium der metallogenese” 2) high technical scoole, košice, slovakia, čssr: theme: “comparative study on metallogeny of dinarides and tatra” 3) uniwersitet jagellonski, kraków, poland: theme: “comparative study on metallogeny of western carpathian and dinarides” 4) 1981. florida state university (fsu), tallahassee, florida, usa: theme: “tracing karstic waters by uranium isotopes” 5) international geological correlation programs (igcp), unesco, paris (1987­1992): project no 287: “correlation of mesozoic tertiary bauxites and related paleokarst phenomena in the tethyan realm”. jurković and dr. andrea mindszenty from eötvös loránd university, budapest as coordinators organized this project which attended scientists from spain, france, italy, austria, hungary, čssr, romania, greece, turkey, egypt, iran, and as opserves scientists from china, india, jamaica, usa and federal republic germany 172 vol. 69/1 6) unesco, paris, igcp­291, (1993­1998): metamorphic fluids and mineral deposits 7) unesco, paris, igcp­356, (1993­1996): „plate tectonic aspects of the alpine metallogeny in the carpatho­balkan region 8) unesco, paris, igcp­369 (1996­1998): “comparative evolution of peritethyan rift basins” 9) pancardi project 2000­2001: theme ”pannonian basin, carpatho–dinaridic systems, dynamics of ongoing orogeny” 10) eötvös loránd university, budapest (hungary) (1995­ 1998): theme: “comparison of bauxites deposits between hungary and yugoslavia” 11) projects within society for geology applied to mineral deposits (sga), freiberg, germany: a) mineral deposits. from their origin to their environmental impacts (1993­ 1995), b) mineral deposits. research and exploration where do they meet (1996­1997), c) mineral deposits. processes and processing (1998­1999), d) mineral deposits and the beginning of the 21st century (2000­2001) the most important results of prof. jurković research works in metallic and nonmetallic ore deposits ore deposits investigated in detail by field and laboratory methods and prepared for exploitation, located in foreign countries 1) a big copper deposit monywa, republic mianmar (ex­ burma) 2) gold bearing copper deposits in the indonesian islands of sumatra and sulawesi 3) tertiary lead­zinc deposit oum geigh at qosseir on the red sea shore, egypt 4) lead­zinc­bearing barite, fluorite deposits on the el kef region, tunisia 5) lead­zinc deposits djebel azered, djebel hamra and djebel agab in the foussana basin, tunisia (un project) 6) a huge iron (itabirite) deposit at san isidro, republic of venezuela with one billion tonnes of iron ore in the republic of croatia 1) barite deposits in the lika, gorski kotar and petrova gora mountain 2) copper bearing siderite deposit of gradski potok and the lead­zinc­bearing siderite deposit of zrin in the trgovska gora mountain 3) hematite ore deposit of bukovica, petrova gora mountain 4) pliocene limonite deposit at meterize, bešlinac, trgovska gora mountain 5) magnetite­hematite occurrences (itabirite) of adolfovac, zagrebačka gora mountain 6) bauxite deposits in northern dalmatia in bosnia and herzegovina 1) metasomatic monomineral barite deposits in the devonian carbonate rocks in the tarčin, kreševo, kiseljak, brestovsko, fojnica, deževice, dusina, sabiljine pećine, rostovo regions (mbsm) 2) veiny mercurian­tetrahedrite­bearing barite­siderite deposits in the silurian and older schists, and sandstones in the mačkara and mračaj deposits 3) bakovići (fojnica); the richest pyrite­siderite gold veiny deposit 4) čemernica (fojnica); a rich silver­bearing zinc­antimony deposit 5) vrtlasce (fojnica); a cassiterite­bearing magnetite, pyrrhotite, lead­zinc deposit 6) hrmza (kiseljak); a realgar and orpiment deposit 7) magnetite, hematite, siderite, ankerite, chalcopyrite and arsenopyrite deposits, mačje jame, busovača 8) lead­zinc­copper bearing barite deposits in the prača region, south­east bosnia bauxite deposits in the ex-yugoslavia jurković and sakač exhibited in 1963 the first stratigraphic position, morphology parageneses and geneses of all bauxite deposits know at that time throughout the ex­yugoslavia. a lecture was held on the foundation day of the international committee of study of bauxite, alumina and al­oxides (icsoba) in the hazu palace, zagreb. evaporites in the western dinarides the most important gypsum and anhydrite deposits localized in the western dinarides differ by their isotope δ34 s values depending on their age of formation. the large and widespread upper permian evaporites found in northern dalmatia, in the una, sana and vrbas valleys are characterized by δ34 s values of + 11.02‰ (61 samples), most of them between +9.0 to +12.5‰. these values are almost identical to the isotopic values of sulphates in permian sea water. relatively small sized, the deposits are locally distributed on the islands of vis and palagruža, in the sinj, bistrica and vareš regions. lower triassic evaporites distinguish high average δ34 s values of +23.3‰ (27 samples), mostly between +20.9 to +25.6‰. lower cretaceous evaporites are found only in deep holes of the adriatic realm, on the islands of vis, brač, dugi otok, olib, krk, susak, lastovo and in north dalmatia. they show δ34 s values of +16.77‰ (105 samples), ranging from +14 to +18‰. synthesis relating to the evaporites from the western dinarides was presented at the 3rd biennal meeting of the sga in prague and published in the balkema publ., rotterdam; jurković & šiftar, 1995 (article no 144). new hypothesis concerning the hercynian metallogeny in the dinarides in the period from 2007 to 2011, jurković was first to use the previously unapplied modern geochemical and other physico-chemical analyses to the investigation of rhyolites and minerals from the all paragenetic types of ore deposits in the 173 palinkaš & bermanec: in memoriam professor emeritus ivan jurković (27.03.1917­30.12.2014) nw­mid­and se bosnia. results of these numerous analyses provided very convincing responses to the earliest mostly unsolved problems. (1) the rhyolite magmatism located in the mid­bosnian schist mountains (mbsm) is not of juvenile origin, but ra­ ther originates from partially melted (anathexis) neoproterozoic and lower palaeozoic rocks as protoliths and therefore the mineralization took place from the metamorphogenic fluids. (2) the most interesting problem for researchers was the presence, of two very strongly different paragenetic types of barite or barite­siderite deposits. the first paragenetic type disitnguishes fe, cu, zn, pb, as and sb sulphides and sulphosalts, all without mercury characterized by low δ34s cdt values (0­5 0/00). barite crystals distinguish a variscan fluid system: nacl­h2o or nacl­kcl­h2o (low th and low salinity). with the δ34s cdt = 11 0/00, δ 18o smow= +14 0/00. the second paragenetic type of barite and barite­siderite deposits distinguishes mercurian tetrahedrites (with 0.34 to 7.58 wt% hg) as the unique main ore mineral. all analysed tetrahedrite samples (n=22) show strongly negative δ34 scdt values ranging from ­4.950/00 to ­15.400/00. barite, fluorite and quartz crystals were identified in the post­ variscan fluid system nacl­cacl2(+,­mgcl2). h2o characteri­ zed by high th and very high salinity. oxygen isotope analyses identified a shift to +18 0/00. strontium analyses of these barite crystals were within the range of values discovered for the first paragenetic type which indicates coeval formation from an identical metamorphogenic fluid, as suggested by jurković in jurković & palinkaš (1999). (3) during the transition phase within the uppermost permian­lower triassic, the early triassic rifting phase caught hold of the whole of the dinarides but with very different intensities. the strongest impact affected the most elevated tectonic blocks of the mbsm, much less the se bosnia block and only sporadically the nw bosnia region. the most significant phenomenon of this first phase of triassic rifting was the ascension of the deep­seated mercury, less fluorine, boron and h2s gases and vapours. these vapours and gases under high pt conditions overprinted all types of pre­existing ore deposits, prior to all barite and barite­siderite sulphide deposits. all sulphides were remobilized, partly or completely fluidized and finally recrystallized, building up the mercury component as mercurian tetrahedrite. the strongly negative δ34scdt values formed by fractionation between ascended h2s and so4 2­ derived from evaporites (jurković et al., 2010; 2011; 2012). 174 vol. 69/1 2017 | 70/2 | 93–103 | 12 figs. | 5 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction nitrates represent one of the most frequent groundwater conta­ minants in the world (peña­haro et al., 2009) and in croatia (larva et al., 2010; nakić et al., 2013). due to their inability to bond in soil by adsorption, they are subject to leaching and in­ filtration into deeper soil layers and groundwater (chowdary et al., 2005; mkandawire, 2008). when they reach ground­ water, they mostly depend on transport and geochemical pro­ cesses in saturated media. many studies have shown strong rela­ tionships between agricultural activity and nitrate concentrations in groundwater (almasri, 2007; peña­haro et al., 2009; li et al., 2010; hosono et al., 2013). also, nitrate concentrations can be a consequence of the simultaneous influence of other an­ thropogenic sources, e.g. septic tanks, sewage and landfills. de­ spite this, there are also different natural factors that have both an influence on their stability and their mobility through the unsatu­ rated and saturated zones. nitrate concentrations can depend on the depth to aquifer, recharge, aquifer media, soil media, topo­ graphy, impact of vadose zone media, hydraulic conductivity, sur­ face leaching and aquifer type (aller et al., 1987; lake et al., 2003). nitrate leaching from the unsaturated zone is a conse­ quence of complex interactions between many factors, e.g. soil characteristics, nitrogen dynamics, depth to water table, land use practice, on­ground nitrogen loading and recharge (almasri, 2003; 2007). dimkić et al. (2008) stated that nitrate concentra­ tions can be predominantly found in aerobic media, where they have high mobility. other nitrogen species, like nitrite and am­ monium ions, are generally stable in predominantly anaerobic media. there are different indicators of aerobic and anaerobic conditions, but concentrations of dissolved oxygen (o2) and the oxidation­reduction potential (orp) represent the most important ones. concentrations of dissolved oxygen between 1 and 2 mg/l, and orp values between 150 to 200 mv, represent the approxi­ mate threshold values for defining the boundary between aerobic influence of groundwater quality indicators on nitrate concentrations in the zagreb aquifer system zoran kovač, zoran nakić and krešimir pavlić university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, 10000 zagreb, croatia; (zoran.kovac@rgn.hr) doi: 10.4154/gc.2017.08 abstract nitrates represent one of the main groups of contaminants in the zagreb aquifer system. some natural groundwater quality indicators can have a significant influence on their stability and mobility in the saturated zone. correlation and multivariate statistical analyses were used to test the correlation of average values of no3 with o2, orp, ph, ec and temperature of groundwater, and to allocate observation wells that belong to the same clusters. orp values didn`t relate to any observed variables, which is probably due to their variability which suggests changes in the oxidation-reduction conditions in the aquifer system. principal component analysis was used for the determination of variables that are related to the nitrate concentrations and which were then used in cluster analysis. other variables were excluded from cluster analysis. three methods were used to perform cluster analysis, where the results calculated with ward`s method were chosen as the most appropriate. in the end, two clusters were identified, one with smaller, and one with higher no3 -, o2 and ec values. observation wells from cluster 1 are generally located near the sava river and have similar nitrate concentrations. lack of other nitrogen species and moderately aerobic conditions suggest very fast nitrification in the shallow holocene aquifer. and anaerobic conditions. kovač et al. (2016) showed that there is a statistically significant positive correlation between nitrate and dissolved oxygen concentrations in the zagreb aquifer. corre­ lation and multivariate statistical analyses are very often used in geochemical research and the identification of potential nitrate contaminant sources (vidal et al., 2000; jeong, 2001; mo­ ratalla et al., 2009). even though nitrates are defined as one of the main group of contaminants in the study area (nakić et al., 2013), and are generally the consequence of anthropogenic influence, the main objective of this work was to define and quan­ tify the correlation of five natural indicators, i.e. o2, orp, ph, electrical conductivity (ec) and temperature of groundwater, on nitrate (no3 ­) concentrations in the zagreb aquifer system. for this purpose, correlation and multivariate statistical analyses (principal component and cluster analysis) were used. principal component analysis (pca) was used for the reduction of variables that were then used in cluster analysis with the purpose of iden­ tifying groups of observation wells with similar characteristics. 2. research area the zagreb aquifer system is located in the nw part of the re­ public of croatia (fig. 1) and it represents the only source of po­ table water for the inhabitants of the city of zagreb and zagreb county. the zagreb aquifer system is designated as a part of countrỳ s strategic water reserves. it is located between medved­ nica mountain in the north and the vukomeričke gorice hills in the south and it covers an area of approximately 350 km2. the wider region is characterized by great variability in lithology, land use, pedological features and the hydraulic properties of the aquifers. the zagreb aquifer system is composed of sediments of quaternary age, deposited during the middle and upper pleis­ tocene and holocene. pleistocene deposits are represented by la­ custrine-marshy deposits, while holocene ones are alluvial de­ article history: manuscript received january 31, 2017 revised manuscript accepted april 24, 2017 available online june 28, 2017 keywords: nitrates, groundwater quality indicators, zagreb aquifer system, multivariate statistical analysis mailto:zoran.kovac@rgn.hr g eo lo gi a c ro at ic a geologia croatica 70/294 posits. microfaunal and microfloral analysis were used for the definition of the main stratigraphic units (sokač, 1978; her­ nitz et al., 1981). changes in the sedimentary environment and petrographical origin of the clasts in gravels and sands was used for the determination of the boundary between pleistocene and holocene deposits. in the beginning of the holocene, the sava river started to flow and transport material from the alps which was mainly carbonate, in contrast to the pleistocene deposits, which were generally siliciclastic (velić & saftić, 1991). overall, lower pleistocene deposits are mostly composed of clayey silts and silty clays with sporadic interbeds and lenses of gravelly sands, while the lower and middle part of the middle pleistocene is composed of sands, with silts and clays discovered in the upper part. the late pleistocene is characterized by fre­ quent lateral changes in gravels, sands, silts and clays, while the holocene is generally composed of gravels and sands (velić & durn, 1993). hydrogeologically, the zagreb aquifer system is divided into three main units (figs. 2 and 3). the first unit is over­ burden, which is in the most part disintegrated by anthropogenic influences. the thickness of this unit generally varies from 2 to 8 m (ružičić et al., 2012). generally, fluvisols, stagnic pod­ zoluvisols and eutric cambisols are developed in the research area (sollitto et al., 2010). the second unit is represented by the shallowest holocene aquifer composed mostly of gravels and sands. the third unit is the deeper pleistocene aquifer characteri­ zed by frequent lateral and vertical alternations of sand, gravel and clays (nakić et al., 2013). the thickness of the holocene aquifer varies from 5 to 40 m, while the deeper aquifer extends up to 60 m depth in the eastern area (nakić et al., 2011). even though these aquifer layers are hydraulically connected, geo­ chemical stratification with depth is recognized. groundwater from the holocene aquifer generally belongs to a camg-hco3 type while the pleistocene aquifer can be additionally characterized by camgna-hco3 hydrogeochemical facies. higher sodium concentrations in groundwater can also be a consequence of an­ thropogenic influence in some areas (vlahović et al., 2009; marković et al., 2013). the holocene aquifer is an unconfined aquifer. it is in direct contact with the sava river, while the general groundwater flow is from w/nw to e/se. the sava river represents the main source of recharge and the main boundary condition. posavec (2006) showed that during medium and low water levels, the sava river drains the aquifer in some areas, while during high water levels it gives water to the aquifer. this means that groundwater levels and the thickness of the unsaturated zone mainly depend on the sava river, which significantly contributes to groundwa­ ter recharge in the study area (miletić & bačani, 1999). industrial development and fast growth of the city of zagreb have affected the groundwater quality in the research area. nakić et al. (2013) have identified pesticides, nitrates, poten­ tially toxic metals, pharmaceuticals and chlorinated aliphatics as the main contaminants. leakage from septic tanks, sewage sys­ tems and agricultural activity present the main potential sources of nitrate contamination in the zagreb aquifer area. nitrate trends are generally decreasing except in the eastern part on the left bank of the sava river (nakić et al., 2016). it has been noted that threshold values, calculated with a vb macro back­ ground (nakić et al., 2007), of nitrate concentrations in groundwater of the wider zagreb area generally range from 7.6 to 18.9 mg/l (nakić et al., 2010; kovač et al., 2013; nakić et al., 2016), depending on the hydrological conditions in which they were calculated. those concentrations suggest existence of figure 1. research area. g eologia c roatica kovač et al.: influence of groundwater quality indicators on nitrate concentrations in the zagreb aquifer system 95 very high ambient background nitrate concentrations in the study area which represents direct evidence of anthropogenic influence on the groundwater quality of the zagreb aquifer. also, ground­ water levels are declining, on average, for 1-2 metres every ten years, while the permanent groundwater reserves have decreased for about 4% from 1976 to 2006 (bačani et al., 2010). the main reasons for groundwater decrease are associated with the deep­ ening of the sava riverbed, increased groundwater abstraction and construction of dykes along the sava river (posavec, 2006). 3. data and methods groundwater quality data from 1991 to 2015 were used for this research. they originate from 153 observation wells of the na­ tional monitoring programme of croatian waters and the moni­ toring programme of the jakuševec landfill. it has been noted that some observation wells were used in the monitoring programme for only a few years, after which they were excluded. also, dif­ ferent sampling intervals have been observed, from monthly to yearly. therefore, given the sampling interval variation and in­ consistent exclusion and inclusion of some observation wells from the monitoring network through observed time period, the data were aggregated at the level of a given observation well. av­ erage values were calculated for all the observed parameters (no3 ­, o2, orp, ph, ec and temperature of groundwater) for each observation well. all values below the limit of quantifica­ tion for nitrate were not taken into account (237 values of no3 ­ in figure 2. a schematic longitudinal hydrogeological profile across the study area (modified according to brkić, 1999). figure 3. schematic cross section hydrogeological profile (modified according to nakić et al., 2016). g eo lo gi a c ro at ic a geologia croatica 70/296 figure 4. average nitrate concentration. figure 5. average dissolved oxygen concentration. g eologia c roatica kovač et al.: influence of groundwater quality indicators on nitrate concentrations in the zagreb aquifer system 97 about 16000 analysis, i.e. ~1.5% of values). due to the lack of orp data for some observation wells, statistical analyses were done using data from just 126 observation wells. a normal dis­ tribution of selected variables was tested by the kolmogorovsmirnov test (d-calculated value; d0-critical value based on number of cases; α=0.05), using statistica 64 (version 13.1) soft­ ware. all data were standardized to z-scores. nitrate concentra­ tions from three river stations (jankomir, petruševec and rugvica, fig. 1) were compared to the nitrate groundwater concentrations. pearson r and spearman ρ correlation coefficients were cal­ culated for all the observed parameters. parametric and nonpara­ metric correlation coefficients were used due to differences in the normal distribution of the selected parameters. there are different classifications concerning the interpretation of correlation co­ efficients. for example, udovičić et al. (2007) stated that cor­ relations coefficients values from 0 to ±0.25 indicate absence of correlation, values from ±0.25 to ±0.50 indicate poor correlation, values from ±0.50 to ±0.75 indicate moderate to good correlation and values from ±0.75 to ±1 indicate very good to excellent cor­ relation. the statistical significance of correlation coefficients was calculated using a t-test (α=0.05), using statistica 64 soft­ ware. principal component analysis (default extraction method under factor analysis in statistica 64) was used to identify the principal components (pc) and variables that create them. var­ imax rotation was used for interpretation of final loadings due to its general successful applicability (hair et al., 2010). cluster analysis was then performed using only those variables that had loadings >±0.5 (which is consistent with guidelines provided in hair et al. (2010)), and were in the same principal component with nitrates. the purpose of cluster analysis was to group obser­ vation wells based on variables obtained from principal compo­ nent analysis. for those purposes cluster analysis was tested us­ ing ward`s method, single linkage and complete linkage rules, while euclidean and squared euclidean distances were used as distance measures. even though there are different rules of thumb that prescribe the minimal requirement of sample size for factor analysis, a minimum of 100 cases (maccallum et al., 1999) and a case/variable ratio of 5:1 (bryant & yarnold, 1995; hair et al., 2010) rule was satisfied. regarding usage of mini­ mal sample size in cluster analysis, mooi & sarstedt (2011) stated that there is no general rule of thumb that provides mini­ mum sample size, or the relationship between the cases and number of clustering variables. in the end, all available ph and orp data were placed on a pourbaix diagram for nitrogen com­ pounds, which shows the possible stable equilibrium phases of an aqueous electrochemical system. for this purpose 3202 pairs of ph and orp values available from groundwater chemical anal­ yses were used. calculations and figure construction was done using microsoft© excel, statistica 64 (version 13.1) and arcmap 10.1, while a geocoded terrain (georeferenced orthophoto) image was obtained from the geoportal of the croatian geodetic ad­ ministration. all maps are presented using the official coordinate system of the republic of croatia (htrs96/tm). 4. results and discussion 4.1. average values of observed variables average nitrate concentrations from 153 observation wells are shown in fig. 4. they vary from 0.8 to 44.20 mgl­1 no3 ­. the highest concentrations are registered in groundwater of the urban part of the city of zagreb (the left bank of the sava river) and in the predominantly agricultural area between mala mlaka and velika gorica city (the right bank of the sava river). dissolved oxygen concentrations are shown in fig. 5 and are divided into 3 groups (<1, 1­2 and >2 mgl­1). dissolved oxygen concentrations were divided into 3 groups to identify observation wells with pre­ dominantly aerobic conditions (>2 mgl­1), predominantly anaero­ bic conditions (<1 mgl­1), and those that have threshold values between the two types of conditions (1-2 mgl­1). it can be seen that predominantly aerobic conditions prevail in the western part of the aquifer system, while more anaerobic conditions occur in the eastern part of the aquifer system and in some observation wells that are located in the vicinity of the sava river. observa­ tion wells that have dissolved oxygen concentrations between 1 and 2 mgl­1 only occur in the eastern part, near the sava river. average orp values vary from 48.82 to 524.89 mv, while ph values vary from 6.98 to 7.63. ec ranges from 425.28 to 1241.4 μs/cm, where the higher values are mostly located on the left bank of the sava river, in the urban part of the city of zagreb. water temperature varies on average from 11.4 to 17 °c. 4.2. correlation results of the kolmogorov-smirnov test are shown in table 1. results show that orp and temperature of groundwater are not normally distributed, while no3 ­, o2, ph and ec show normal distribution patterns. correlation coefficient matrices for r and ρ are shown in ta­ ble 2. all statistically significant results are marked in red. generally, the results show that nitrate concentrations are more related to ph, o2 and ec, where correlation with ph is negative, while correlation with the other two parameters is positive. positive cor­ relations of no3 ­ with o2 and ec seem very logical because higher o2 concentrations should provide a more stable geo chemical table 1. results of kolmogorov-smirnov test. variable d d0 n normal distribution no3 0.117 0.121 126 yes orp 0.200 0.121 126 no o2 0.092 0.121 126 yes ph 0.096 0.121 126 yes ec 0.094 0.121 126 yes temperature 0.137 0.121 126 no table 2. pearson and spearman correlation matrix. pearson parameter temperature ph orp o2 ec no3 – temperature 1.00 ph –0.13 1.00 orp –0.15 0.24 1.00 o2 –0.32 –0.60 –0.05 1.00 ec 0.21 –0.95 –0.28 0.51 1.00 no3 – 0.06 –0.74 –0.13 0.74 0.76 1.00 spearman parameter temperature ph orp o2 ec no3 – temperature 1.00 ph –0.16 1.00 orp –0.15 0.24 1.00 o2 –0.37 –0.56 –0.02 1.00 ec 0.17 –0.97 –0.27 0.54 1.00 no3 – –0.05 –0.76 –0.07 0.76 0.78 1.00 g eo lo gi a c ro at ic a geologia croatica 70/298 environment for nitrates, while higher ec values are generally as­ sociated with higher human impact, resulting in higher concentra­ tions of dissolved substances, including higher no3 ­ concentrations. ph is negatively correlated with o2, ec and no3 ­. orp values show no or very poor correlation with all other variables, as well as with the groundwater temperature. usually it is suggested that pearson correlation coefficient shoudǹ t be used when variables are not nor­ mally distributed. it has to be stressed that both pearson and spear­ man correlation statistics for orp and groundwater temperature are very similar indicating that in some cases pearson correlation coefficient can be used although all variables don’t follow the nor­ mal distribution. it is obvious that the pearson correlation coeffi­ cient can be used when only one variable has a normal distribution and when a sufficiently large data size is available, which is consist­ ent with recommendations provided by udovičić et al. (2007). 4.3. principal component analysis principal component analysis generated 2 principal components explaining 76% of the total variance, where 54% was explained by the first component. varimax raw rotated loadings are shown in table 3, together with its communalities. pc 1 is presented with ph, o2, ec and no3 ­, while pc 2 is presented with groundwater temperature and orp. it is evident that an oxygenated environ­ ment generates higher nitrate concentrations and ec values which results in a more acidic environment. also, results indicate that the orp and temperature of groundwater are not related to nitrate concentrations, which coincides with previous results. further­ more, results suggest that orp and groundwater temperature present variables that are less under human influence than the vari­ ables from pc 1. due to very low communalities of orp (<0.5) and the affiliation of the temperature of groundwater to different principal components, these two variables were excluded from the cluster analysis. varimax rotation loadings are shown in fig 6. 4.4. cluster analysis cluster analysis was performed using three different methods, where ward`s method generated the two most distinctive clusters (fig. 7 and 8). in all cases squared euclidean distances and eu­ clidean distances gave similar results. however, the squared dis­ tances facilitated the drawing of conclusions regarding the num­ ber of clusters. the results of cluster analysis obtained using ward`s method have been taken as the most representative one, which is probably a consequence of ward`s method of calculation. single and link­ age methods define the similarity of clusters using minimum and maximum distances between objects, while ward`s methods maximizes the homogeneity between clusters using the sum of squares within the cluster. evaluation of projected clusters have shown two main results. first, clusters have very distinctive con­ centrations of no3 ­, o2 and ec (table 4). cluster 1 has generally lower values of variables, while cluster 2 has higher values. in cluster 1 the average value of o2 from 61 observation wells is 1.77 mgl­1, of ec is 573.31 μs/cm, and of no3 ­ is 7.84 mgl­1. in cluster 2 the average value of o2 from 65 observation wells is 4.8 mgl­1, table 3. pca results. variable varimax rotation communalities pc 1 pc 2 from 1 pc from 2 pc multiple r-square temperature 0.04 –0.87 0.00 0.75 0.33 ph –0.93 0.13 0.87 0.89 0.93 orp –0.28 0.51 0.08 0.34 0.11 o2 0.78 0.49 0.61 0.84 0.74 ec 0.92 –0.24 0.85 0.90 0.93 no3 0.91 0.08 0.82 0.83 0.78 figure 6. varimax raw rotated variable loadings on pc 1 and pc 2. g eologia c roatica kovač et al.: influence of groundwater quality indicators on nitrate concentrations in the zagreb aquifer system 99 of ec is 859.03 μs/cm, and of no3 ­ is 25.93 mgl­1. these results indicate that no3 ­ concentrations are generally controlled by o2 concentrations. also, where higher concentrations of ec are re­ corded, higher nitrate concentrations can also be expected, which is also confirmed by correlation analysis. secondly, if clusters are evaluated spatially (fig. 9), observation wells in different clusters generally coincide with the average values of dissolved oxygen shown in fig. 3. most of the observation wells from cluster 1 are near the sava river, in the area with the lower oxygen content. nitrate concentrations in the sava river have average concentra­ tions of 7.33 mgl­1 at the jankomir station, 7.5 mgl­1 at the petruševec, and 6.67 mgl­1 at rugvica (table 5), while the avefigure 7. tree diagram with ward`s method (euclidean distances). figure 8. tree diagram with ward`s method (squared euclidean distances). g eo lo gi a c ro at ic a geologia croatica 70/2100 rage no3 ­ concentrations in cluster 1 are similar, i.e. 7.84 mgl­1. lower values of o2 in the eastern part of the zagreb aquifer sys­ tem are probably a consequence of greater aquifer depth and mix­ ing of different groundwaters from holocene (more oxidative condition) and pleistocene aquifers (more reductive condition). also, results indicate that the sava river has an influence on the dissolved oxygen concentrations. the reasons for this could be varied. they can be associated with too many bacteria and an excess amount of biological oxygen demand, and maybe with fer­ tilizer runoff from farm fields. the first reason is the more likely in this case because it can be associated with some kind of or­ ganic discharge, probably sewage. these results indicate that the quality of the sava river is under very significant anthropogenic influences. 4.5. pourbaix diagram and dominant nitrogen species in general, all statistical analyses showed the close relationship of no3 ­, o2, ec and ph. orp and groundwater temperature showed a very poor relationship with the other variables. when evaluating the pourbaix diagram for nitrogen species and mea­ sured data (fig. 9) in the zagreb aquifer, it can be seen that all values are oriented more in a vertical than in a horizontal direc­ tion. this indicates constant change in oxidative and reductive conditions in the zagreb aquifer, which is also probably the rea­ son why the correlation between no3 ­ and orp caǹ t be ob­ table 5. average, minimum and maximum values of nitrate in the sava river. station parameter no3 – (mg/l) jankomir average 7.33 minimum 1.33 maximum 27.01 petruševec average 7.5 minimum 1.77 maximum 25.67 rugvica average 6.67 minimum 3.94 maximum 8.76 table 4. average, minimum and maximum values of two defined clusters. variable number of observation wells temperature (°c) ph orp (mv) o2 (mg/l) ec (μs/cm) no3 – (mg/l) cluster 1 average 61 13.66 7.38 254.30 1.77 573.31 7.84 minimum 11.58 7.10 48.83 0.21 425.28 0.57 maximum 17.02 7.63 524.89 5.63 871.86 26.36 cluster 2 average 65 13.50 7.14 234.27 4.80 859.03 25.93 minimum 11.43 6.98 134.00 0.69 451.83 6.26 maximum 15.59 7.53 477.24 7.53 1241.40 44.20 figure 9. clusters of observation wells with similar characteristics. g eologia c roatica kovač et al.: influence of groundwater quality indicators on nitrate concentrations in the zagreb aquifer system 101 served. in fig. 10 it can be seen that the most frequent average orp class is that between 150 and 200 mv, which presents the threshold class between oxidative and reductive conditions in the aquifer (dimkić et al., 2008). also, fig. 10 shows that about 50% of observation wells have orp values higher than 200 mv, which suggests that in the zagreb aquifer system moderately oxifigure 10. pourbaix diagram for nitrogen species at zagreb aquifer (background picture modified according to puigdomenech, 2006; husson, 2013). figure 11. histogram of average orp values at zagreb aquifer. figure 12. occurrence of nh4 + and no2 concentrations in zagreb aquifer from 1991 to 2015. g eo lo gi a c ro at ic a geologia croatica 70/2102 dative conditions prevail. furthermore, from fig. 11 it can be seen that many samples fall in the area of high nh4 + stability. due to the very rare occurrence of nh4 + (367 values at 49 observation wells) and no2 ­ concentrations (249 values at 69 observation wells) observed in 25 years of groundwater quality monitoring of the zagreb aquifer system (fig. 12), it can be assumed that very rapid nitrification of nh4 + and no2 ­ to no3 ­ occurs in the aquifer system. moreover, fig. 12 shows that concentrations of nh4 + and no2 ­ on most observation wells occur less than five times in the observed period. 5. conclusion nitrates represent one of the main groups of contaminants in the zagreb aquifer system. their concentrations are mainly the result of anthropogenic influences. despite this, some natural ground­ water quality indicators, more or less influenced by humans, may affect their stability and mobility in groundwater. average values of no3 ­, o2, orp, ph, ec and the temperature of groundwater were used to test their relationship using correlation and multi­ variate statistical analysis. pearson and spearman correlation sta­ tistics have produced similar results in that no3 ­ is generally positively correlated with o2 and ec, and negatively with ph. orp values showed no to very poor correlation with all other variables, as well as with the temperature of groundwater. cor­ relation analysis indicated that only o2, ec and ph were variables related to nitrate, which was confirmed with multivariate statis­ tical analysis results. pca was used to identify principal compo­ nents and variables which were then used as variables in the clus­ ter analysis. it generated 2 pcs where only ph, o2, ec and no3 ­ from pc 1, with factor loadings >±0.5, were used in the cluster analysis. cluster analysis was tested with ward`s method, single linkage and complete linkage rules, while euclidean and squared euclidean distances were used as distance measures. different distance measures did not provide any significantly dif­ ferent results of the cluster analysis, but linkage rule methods did. ward`s method generated two most distinctive clusters, probably because of the difference in calculation of the difference between clusters, and its results were used for the evaluation of two clus­ ters. clusters mostly differ in o2, ec and no3 ­ concentrations. in cluster 1 lower values of no3 ­ are probably a consequence of the influence of the sava river and greater aquifer depth in the eastern part of the aquifer system, where mixing of anaerobic and aerobic water occurs. due to the great variability of orp in the study area and lack of nh4 + and no2 ­ species in groundwater, it can be assumed that very rapid nitrification of nh4 + and no2 ­ to no3 ­ occurs in the zagreb aquifer system, particularly in the shal­ low holocene aquifer. acknowledgment authors would like to thank croatian waters for the data obtained within the project „groundwater trend and status assessment in the pannonian part of croatia” and to zagreb holding (branch zgos) for the data obtained from monitoring program of landfill jakuševec. references aller, l., bennett, t. & lehr, j.h. (1987): drastic: a standardized system for evaluating groundwater pollution potential using hydrogeologic settings. us epa/600/2–87/035. almasri, m.n. (2003): optimal management of nitrate contamination of ground wa­ ter.– phd dissertation. utah state university, logan, utah, 229 p. almasri, m.n. (2007): nitrate contamination of groundwater: a conceptual manage­ ment framework.– environmental impact assessment review, 27, 220–242. doi:10.1016/j.eiar.2006.11.002. bačani, a., posavec, k. & parlov, j. (2010): groundwater quantity in the zagreb aquifer.– in: zuber, a., kania, j. & kmiecik, e. (eds.): xxxviii iah con­ gress groundwater quality sustainability, krakow, september 12–17, 2010, 87–92. brkić, ž. (1999): napajanje aluvijalnih vodonosnika sjeverne hrvatske kroz slabije propusne krovinske naslage [alluvial aquifer recharge through semipermeable covering deposits in northern croatia – in croatian].– unpubl. phd thesis, fac­ ulty of mining, geology and petroleum engineering, university of zagreb, zagreb, 157 p. bryant, f.b. & yarnold, p.r. (1995): principal components analysis and explora­ tory and confirmatory factor analysis.– in: grimm, l.g. & yarnold, r.r. (eds.): reading and understanding multivariate statistics, 99–136. washington, dc: american psychological association. chowdary, v.m., rao, n.h. & sarma, p.b.s. (2005): decision support frame­ work for assessment of non­point­source pollution of groundwater in large irriga­ tion projects.– agricultural water management, 75, 194–225, doi: 10.1016/j.ag­ wat.2004.12.013. dimkić, m.a., brauch, h.j. & kavanaugh, m. (2008): groundwater manage­ ment in large river basins.– iwa publishing, alliance house, biddles ltd, norfolk, uk. hair, jr., j.f., black, w.c., babin, b.j. & anderson, r.e. (2010): multivari­ ate data analysis.– seventh edition, prentice hall, upper saddle river, nj 07458, 785 p. hernitz, z., kovačević, s., velić, j. & urli, m. (1981): primjer kompleksnih geološko-geofizičkih istraživanja kvartarnih naslaga u okolici prevlake [an example of complex geological and geophysical explorations of wuaternary deposits in the soroundings of prevlaka – in croatian].– geološki vjesnik, 33, 11–34, zagreb. hosono, t., tokunaga, t., kagabu, m., nakata, h., orishikida, t., lin, i. & shimada, j. (2013): the use of δ15n and δ18o tracers with an understan­ ding of groundwater flow dynamics for evaluating the origins and attenuation mechanisms of nitrate pollution.– water research, 47, 2661–2675. doi:10.1016/j. watres.2013.02.020 husson o. (2013): redox potential (eh) and ph as drivers of soil/plant/microorgan­ ism systems: a transdisciplinary overview pointing to integrative opportunities for agronomy.– plant soil, 362, 389–417. doi:10.1007/s11104-012-1429-7. jeong, c.h. (2001): effect of land use and urbanization on hydrochemistry and con­ tamination of groundwater from taejon area, korea.– journal of hydrology 253(1–4), 194–210. doi: 10.1016/s0022-1694(01)00481-4. kovač, z., nakić, z., posavec, k., parlov, j. & bačani, a. (2013): ambient background concentrations of chemical parameters in groundwater of samobor aquifer. waters in sensitive and protected areas (isbn: 978-953-96071-3-3), 163–166. kovač, z., pavlić, k. & nakić, z. (2016): influence of dissolved oxygen on nitrates concentration in zagreb aquifer. 8th croatian­hungarian and 19th hungarian geo­ mathematical congress, geomathematics – present and future of geological mod­ elling, 89–96 (isbn: 978-953-59036-1-1). lake, i.r., lovett, a.a., hiscock, k.m., betson, m., foley, a., sunnen­ berg, g., evers, s. & fletcher, s. (2003): evaluating factors influencing groundwater vulnerability to nitrate pollution: developing the potential of gis.– journal of environmental management, 68, 315–328. doi: 10.1016/s03014797(03)00095-1 larva, o., marković, t. & brkić, ž. (2010): groundwater hydrochemistry of the quaternary alluvial aquifer in varaždin region — croatia. xxxviii iah congress (issn: 0208-6336).– groundwater quality sustainability, krakow, 493–500. li, s.l, liu, c.q., lang, y.c., zhao, z.q. & zhou, z.h. (2010): tracing the sources of nitrate in karstic groundwater in zunyi, southwest china: a combined nitrogen isotope and water chemistry approach.– environmental earth sciences, 60, 1415–1423, doi: 10.1007/s12665-009-0277-0. maccallum, r.c., widaman, k.f., zhang, s. & hong, s. (1999): sample size in factor analysis. psychological methods, 4, 84–99. doi: 10.1037/1082989x.4.1.84 marković, t., brkić, ž. & larva, o. (2013): using hydrochemical data and mode lling to enhance the knowledge of groundwater flow and quality in an al­ luvial aquifer of zagreb, croatia.– science of the total environment, 458–460, 508–516, doi: 10.1016/j.scitotenv.2013.04.013. miletić, p. & bačani, a. (1999): egpv: izrada bilansa [development of water balance – in croatian]. book 4, 4th part. faculty of mining, geology and petroleum engineering, university of zagreb, zagreb. mkandawire, t. (2008): quality of groundwater from shallow wells of selected vil­ lages in blantyre district, malawi.– physics and chemistry of the earth 33/(8–13). doi: 807–811, doi:10.1016/j.pce.2008.06.023. mooi, e. & sarstedt, m. (2011): a concise guide to market research. the proc­ ess, data, and methods using ibm spss statistics. isbn: 978-3-642-12541-6, 307 p. g eologia c roatica kovač et al.: influence of groundwater quality indicators on nitrate concentrations in the zagreb aquifer system 103 moratalla, a., gómez-alday, j.j. & de las heras, j. (2009): nitrate in the water-supply wells in the mancha oriental hydrogeological system (se spain).– water resources management, 23/8, 1621–1640. doi: 10.1007/s11269-008-9344-7. nakić, z., ružičić, s., posavec, k., mileusnić, m., parlov, j., bačani, a. & durn, g. (2013): conceptual model for groundwater status and risk assess­ ment – case study of the zagreb aquifer system.– geologia croatica, 66/1, doi: 10.4154/gc.2013.05. nakić, z., posavec, k. & bačani, a. (2007): a visual basic spreadsheet macro for geochemical background analysis.– ground water 45/5, 642–647. print issn: 0017-467x, online issn: 1745–6584. doi: 10.1111/j.1745-6584.2007.00325.x. nakić, z., posavec, k. & parlov, j. (2010): model-based objective methods for the estimation of groundwater geochemical background. aquamundi 1, no. 1: 065-072. print issn: 2038-3584, online issn: 2038-3592. nakić, z., posavec, k., parlov, j. & bačani, a. (2011): development of the conceptual model of the zagreb aquifer system. the geology in digital age: proceedings of the 17th meeting of the association of european geological soci­ eties, maegs 17 / banjac, n. (ed.).– belgrade: serbian geological society, 2011. 169–174 (isbn: 978-86-86053-10-7). nakić, z., bačani, a., parlov, j., duić, ž., perković, d., kovač, z., tu­ mara, d., mijatović, i., špoljarić, d., ugrina, i., stanek, d. & slavinić, p. (2016): definiranje trendova i ocjena stanja podzemnih voda na području panonskog dijela hrvatske [groundwater trend and status assessment in the pannonian part of croatia – in croatian].– stručna studija, rudarsko-geološkonaftni fakultet, sveučilište u zagrebu. peña-haro, s., pulido-velazquez, m. & sahuquillo, a. (2009): a hydroeconomic modelling framework for optimal management of groundwater nitrate pollution from agriculture.– journal of hydrology, 373, 193–203, doi: 10.1016/j. jhydrol.2009.04.024. posavec, k. (2006): identifikacija i prognoza minimalnih razina podzemne vode zagrebačkoga aluvijalnog vodonosnika modelima recesijskih krivulja [identification and prediction of minimum ground water levels of zagreb alluvial aquifer using recession curve models – in croatian].– unpub. phd thesis, faculty of mining, geology and petroleum engineering, university of zagreb, zagreb, 89 p. puigdomenech, i. (2006): hydra (hydrochemical equilibrium-constant data­ base) and medusa (make equilibrium diagrams using sophisticated algo­ rithms) programs. royal institute of technology, stockholm. http://www.kemi. kth.se/medusa/ ružičić, s., mileusnić, m. & posavec, k. (2012): building conceptual and mathematical model for water flow and solute transport in the unsaturated zone at kosnica site.– rudarsko-geološko-naftni zbornik (0353-4529), 25, 21–31. sokač, a. (1978): pleistocene ostracode fauna of the pannonian basin in croatia. pale­ ont. jugoslav., 21, 1–51. sollitto, d., romić, m., castrignano, a., romić, d. & bakić, h. (2010): assessing heavy metal contamination in soils of the zagreb region (northwest croatia) using multivariate geostatistics.– catena, 80, 182–194. doi: 10.1016/j. catena.2009.11.005 udovičić, m., baždarić, k., bilić-zule, l. & petrovečki, m. (2007): što treba znati kada izračunavamo koeficijent korelacije? [what we need to know when calculating the coefficient of correlation?].– biochemia medica, 17/1,1–138. vlahović, t., bačani, a. & posavec, k. (2009): hydrogeochemical stratifica­ tion of the unconfined samobor aquifer (zagreb, croatia).– environmental geology, 57/8, 1707–1722. doi: 10.1007/s00254-008-1452-4. velić, j. & durn, g. (1993): alternating lacustrine-marsh sedimentation and sub­ aerial exposure phases during quaternary: prečko, zagreb, croatia.– geologia croatica, 46/1, 71–90. doi: 10.4154/gc.1993.06 velić, j. & saftić, b. (1991): subsurface spreading and facies characteristics of middle peistocene deposits between zaprešić and samobor.– geološki vjesnik, 44, 69–82. vidal, m., melgar, j., lopez, a. & santoalla, m.c. (2000): spatial and tem­ poral hydrochemical changes in groundwater under the contaminating effects of fertilizers and wastewater.– journal of environmental management, 60/3,215–225. doi: 10.1006/jema.2000.0379 http://www.kemi.kth.se/medusa/ http://www.kemi.kth.se/medusa/ www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2024 | 77/3 | 253–268 | 4 figs. | 1 tab. | 2 pls. | 3 suppl. | 1. introduction 1.1. general background palynological analysis provides a window into the past land­ scape (traverse, 2007) and vegetation history reconstructed by high­resolution pollen analysis which is an important tool in the understanding of climatic change, ecological restoration and recording human impact on the environment (shang & li, 2010). in sensu stricto meaning, palynology allows plant identification on local/extra-local or regional levels (considering plants’ dispersal strategies) and reconstruction of plant cover (in the case of statistically significant proportions of palynomorphs in the substrate samples). moreover, ecological indi­ cator values of particular pollen species highlights temperature changes, hydrological or trophic substrate level in the particular study area and possible human impacts on the environment (court-picon et al., 2006; andrič, 2007; feurdean et al., 2013; kulkarni et al., 2016; hruševar et al., 2020). in sensu lato meaning, other microorganic proxies known as non­pollen palynomorphs (npps), including amoebae, fungal spores, algal cists, zooclast, etc., can be useful in explaining and confirming palaeoenvironmental changes (karpińskakołaczek et al., 2014; dietre et al., 2016; doyen & etienne, 2017; wojewódka & hruševar, 2020; welc et al., 2021; druzhinina et al., 2023). due to their restricted dispersal possibilities, npps often provide a local signal which can be directly related to anthropogenic activities the role of pollen and npp research in palaeoenvironmental reconstruction of the neolithic archaeological site “gorjani-topole” (slavonia region, eastern croatia) dario hruševar1, koraljka bakrač2,*, božena mitić1, ivona baniček2 and rajna šošić klindžić3 1 university of zagreb, faculty of science, department of biology, horvatovac 102a, 10000 zagreb, croatia; (dario.hrusevar@biol.pmf.unizg.hr; bozena.mitic@biol.pmf.unizg.hr) 2 croatian geological survey, department of geology, sachsova 2, 10000 zagreb, croatia; (*corresponding author: kbakrac@hgi-cgs.hr; ibanicek@hgi-cgs.hr) 3 university of zagreb, faculty of humanities and social sciences, department of archaeology, 10000 zagreb, croatia; (rsosic@ffzg.unizg.hr) doi: 10.4154/gc.2024.15 abstract the palynological study of eight samples from the gorjani-topole archaeological site was conducted with the aim of palaeoenvironmental reconstruction. in total, 44 different palynomorphs were recorded: 12 pollen taxa, 23 fungal spores/remains, four algal cysts, one amoebae and four palynomorphs of unknown origin. among the non-pollen palynomorphs, chomotriletes (previously pseudoschizaea) occurred with the greatest frequency and abundance. the low pollen richness accompanied by the presence of only a few sporopolleninrich pollen types indicates unfavourable preservation conditions in the analysed core samples. the dominance of erosion/desiccation indicators supports the scenario of significant oscillations of the hydrological level in the sediments, with periodic drying of the substrate. although the interpretation of changes in plant cover, due to the reduced pollen spectrum, is not feasible, it is still possible to indicate paleoecological trends and partially interpret them, considering the indicator value of the few preserved palynomorphs. the findings of cultivated grass pollen (cerealia) and other anthropogenic indicators including weed pollen (convolvulus arvensis) are of great importance. moreover, riccia moss spores or fungal epicoccum spores could also indicate the anthropogenic impact on the study area. (shumilovskikh & van geel, 2020). in archaeological research and interpretation, pollen and npp analysis becomes almost a standard tool for understanding the interaction be tween humans and nature (bakels, 2020; shumilovskikh & van geel, 2020), although a multiproxy approach often depends on project finances and execution time (druzhinina et al., 2023). charcoal particles, as indicators of fire history, are created by the burning of vegetation, often caused by human activity (mooney & tinner, 2011). however, the distinction between naturally caused and artificial fires still remains problematic in interpretation. since botanical data for the gorjani­topole (gt) site during the neolithic are com­ pletely missing, the aim of this work was to use both pollen and non­pollen palynomorphs for palaeoenvironmental recon­ struction. more specific objectives were: (i) to obtain additional information about the neolithic flora of eastern croatia, (ii) to gain information about the human economy of that area, and (iii) to enable a better understanding of the depositional pro­ cesses in loess deposits. 1.2. location, physical environment and vegetation the gorjani­topole (gt) archaeological site is located in slavonia, eastern croatia (fig. 1), approximately 10 km northwest of đakovo town and 2 km east of gorjani village. administratively, the area belongs to the osijek-baranja county. article history: manuscript received: april 04, 2024 revised manuscript accepted: july 01, 2024 available online: october 01, 2024 keywords: archaeology, non-pollen palynomorphs, pollen, sopot culture, zag g eo lo gi a c ro at ic a 254 geologia croatica 77/3 the village was an important medieval centre, situated on the northern edge of the đakovo loess plateau (njegač, 2002), built mainly from loess and loess-like quaternary deposits (korolija & jamičić, 1989 a,b; lehmkuhl et al., 2021). cores were acquired in locations where loess was deposited (fig. 2a). the precise position of the study site is defined by the coordinates 45°23'n 18°23'e, at an altitude of ~ 110 m a.s.l. (šošić klindžić et al., 2019). according to köppen’s climatic classification, the studied site belongs to the cfb climate type; it has a moderately hot, humid climate with warm summers with a mean temperature of the hottest month below 22 °c. in a recent decade (from 2009 to 2018 inclusive), the average annual temperature slightly exceeded 12 °c, and the average annual precipitation varied around 700 mm (klepo, 2020), of which about 390.2 mm fell during the growing season (leko, 2016). the common northwest wind blows throughout the year (klepo, 2020). today the đakovo plateau is under high human pressure and intensively cultivated arable land prevails, therefore floodplain oak forests and mixed oak-hornbeam forests have been strongly reduced. only small patches of alder-oak riparian floodplain forests on nutrient-rich alluvial soils of the temperate regions of the balkan peninsula (alliance alno-quercion roboris horvat 1950) and oak-hornbeam forests on the deep figure 1. a) the study area: the position of gorjani-topole within the national/regional borders; b) position of the archaeological site on a local level, recognised below intensively cultivated arable land; c) potential vegetation (if the anthropogenic impact was absent) on the broader area. figure 2. position of cores 1, 3, 4 and 6 on the basic geological map (korolija & jamičić, 1989a) and a magnetogram of the site of gorjani topole. g eologia c roatica 255hruševar et al.: the role of pollen and npp research in palaeoenvironmental reconstruction of the neolithic archaeological site “gorjani-topole” ... 2. materials and methods 2.1. fieldwork archaeological field research was conducted during the spring of 2021. sites were cored using a gasoline powered percussion ham mer vibrokorer eijkel kamp cobra tt rd32 equipped with percussion gouges, used to take reasonably undisturbed sam ples from depths to about 7 metres, without the use of a drill ing liquid (so samples were suitable for chemical analysis). samples were extracted from the piston corer in the field and stored in a cold store at 4°c. ten samples were prepared for grain­size analysis and eight samples for palynological analysis from four different cores (fig. 3). 2.2. laboratory work the acid-alkaline treatment of the sediment was done at the croatian geological survey. sediments were passed through the 250 μm and 10 μm mesh sieves, so the analysed organic fraction was between these specified sizes. in order to enable mutual comparison of the size differentiated samples analysed, lycopodium tablets (stockmarr, 1971) of known spore concentration (batch no. 280821291; 13761 spores/tablet) were added to each sample. the preparation procedure included treatment with cold hcl for carbonate removal and hf for silicate removal, while sodium pyrophosphate (na4p2o7) enables the dispersion of clay particles and heavy liquid (zncl2) was applied to separate the organic matter from the undissolved inorganic fraction. the above mentioned pro cedure is in accordance with faegri & iversen (1989) and moore et al. (1991). palynomorphs were stored in silicate oil. 2.3. palynological analysis all analysed proxies: pollen, npps and charcoal were counted on the same slide using an olympus bh­2 transmitted light microscope at x400, x600 and x1000 (oil immersion), magnifications combined with the interference contrast. photomicrographs were taken with an amscopetm camera adapter connected to amscope v.3.7 camera software. palynomorph concentration was calculated by the formula: palynomorphs conc. = ((number of lycopodium spores added) x (number of particles counted)) / ((number of lycopodium spores counted) x (weight of dry sediment processed in grams)), following maher (1981). the pollen and plant spore identification was based on pollen keys: moore et al. (1991), beug (2015) and the reference collection of the department of biology, faculty of science, university of zagreb. palynological residues and slides are stored in the collection of the croatian geological survey. the identification of nonpollen palynomorphs was based on the following publications: van geel et al. (1983), van geel et al. (1989), scott (1992), pantaleón-cano et al. (1996), kuhry (1997), carrión & van geel (1999), carrión & navarro (2002), revelles et al. (2016), revelles & van geel (2016). the npp names were adjusted to those of miola (2012). newly described palynomorphs are followed by the abbreviation zag, already used for palynomorph description in collaboration with the university of zagreb, faculty of science and croatian geological survey (eg. druzhinina nutrient-rich soils of the balkans and northern italy (alliance erythronio-carpinion (horvat 1958) marinček) remain (bioportal, 2023). the forest coverage of the osijek-bara nja county is 28.93 %, which is significantly below the 44 % which is the national average (anonymous, 2017). potential vege ta tion of the gorjani area within a 10 km radius includes forests dominated by the common oak (quercus robur l.), sessile oak (q. petraea) and common hornbeam (carpinus betulus) within carpino-quercetum roboris, genisto-quercetum roboris s. lat. and quercetum petraeae s. lat. (nikolić, 2015). beech trees of luzulo albidae-fagetum s. lat. dominated the slopes of the nearby higher hills of dilj mt. according to trinajstić (1998) vegetation of that area belongs to the european planar vegetation belt of the euro­siberian – north american region. 1.3. previous archaeological research the location of the archaeological site gorjani­topole (gt) was confirmed by geophysical research and archaeological excavation a few years ago (šošić klindžić et al., 2021), although it was discovered much earlier, in 2007 from google earth satellite imagery (šošić klindžić et al., 2019). systematic excavations began in 2020, but were latter interrupted by the covid 19 pandemic and continued in 2021 (šošić klindžić et al., 2024). the study site, located at an altitude of 110 m a.s.l. consists of three ditches and a circular settlement, with the outer enclosure occupying 1.15 ha. the middle enclosure covers 0.82 ha, and the inner enclosure occupied 0.82 ha. a magnetic survey of the area also showed the expansion of the settlement outside the enclosed areas. excavation took place on part of the outer ditch, inner ditch and palisade as well as the remains of a house. a comprehensive description of the site is presented in šošić klindžić et al. (2019, 2024). pottery fragments discovered on the gt site belong to the sopot culture (šošić klindžić et al., 2019), with a calibrated date range from 12 samples from 4900 to 4300 cal years bc (šošić klindžić et al., 2024). south of the enclosure, some fragments of pottery belonging to the starčevo culture were also found (šošić klindžić et al., 2019). thanks to the long tradition of sopot culture research, with regular excavations from the 1970s, many archaeological sites dated ~5000 bc have been identified (šošić klindžić et al., 2021) leading to a hypothesis that the gt study site was part of the network of settlements separated by distances of between 3 and a maxi mum of 6 km (kalafatić et al., 2021). although archaeological excavations are numerous, and knowledge about the sopot culture is accumulating, relatively little is known about animal husbandry in eastern croatia during the neolithic. according to tomac (2022), food economy in the late neolithic of eastern croatia corresponds well to what is generally known from that period on a regional scale. although the archaeozoological remains from gt were insufficient for any extensive conclusion, the nearby archaeological site of gorjani-kremanjača, situated less than one kilometre from the gt study site, indicates that cattle were, without any doubt, the most important animal species for the inhabitants of the broader gorjani area, followed by pigs and caprines (sheep and goats collectively), (tomac, 2022). g eo lo gi a c ro at ic a 256 geologia croatica 77/3 et al., 2023). on the same palynological slides pollen, npps and charcoal were observed and counted. 3. results the multiproxy study includes eight samples, isolated from the four cores: gt-1, gt-3, gt-4, gt­6 that were conducted with the aim of palaeoenvironmental reconstruction. grain-size analysis identifies silt as the dominant grain­size fraction in all the studied samples. in addition, the samples contain small amounts of clay-sized (13-21 %) and sand-sized (1-8 %) minerals (suppl. 1). 3.1. palynomorphs and charcoal in total, 44 different polymorphs were recorded: 12 pollen taxa, 23 fungal spores/remains, four algal cysts, one amoebae and four palynomorphs of unknown origin (suppl. 2). within nonpollen palynomorphs, 22 previously unde­ scribed morphotypes were recorded here based on morphological features (pl. 1, table 1). palyno morph concentrations range from 5x103 to 2x105 palynomorphs per gram (suppl. 3). for reconstruction of possible palaeoecological trends, each palynomorph was assigned to one of four different ecological categories: i) indicators of wetness, ii) indicators of erosion/ dessication, iii) indicators of anthropogenic influence and iv) unknown (fig. 3). the gt-1 (158-168 cm) sample contains 5,504 pollen grains/g, 33,026 npps/g and 517,414 charcoal particles/g (suppl. 3). within arboreal pollen (ap), only corylus was observed, and non­arboreal pollen (nap) is completely missing. npps were dominated by hdv-351 and nigrospora, and only one chomotriletes was counted (suppl. 2). charcoal particles were rare (suppl. 2). indicators of anthropogenic influence prevailed, and indicators of erosion/dessication were sparsely presented (fig. 4). the gt­1 (60­70 cm) sample contains 8,257 pollen grains/g, 123,849 npps/g and 1.629,302 charcoal particles/g (suppl. 3). within ap, only quercus was observed, and nap is completely missing. npps were dominated by chomotriletes, succeeded by hdv-38 and hdv200. charcoal particles were numerous (suppl. 2, suppl. 3). only indicators of erosion/dessication were represented (fig. 4). sample gt-1 (50-60 cm) contains 5,504 pollen grains/g, 126,601 npps/g and 11.504,196 charcoal particles/g (suppl. 3). within ap, only alnus was observed, and nap is completely missing. npps were dominated by chomo triletes and glomus. moreover, in this sample chomotriletes and charcoal particles reach the highest figure 3. positions of the samples; red dots for palynology, and yelow dots for grain-size analysis. g eologia c roatica 257hruševar et al.: the role of pollen and npp research in palaeoenvironmental reconstruction of the neolithic archaeological site “gorjani-topole” ... table 1. descriptions of newly observed npp types. npp types descriptions zag-4 fungal spores, claster of three cells, each 18 x 14 μm; monosepate, slightly constricted at septum, dark redish-brown colour. zag-5 multicellular fungal palynomorph with eight cells, irregular in shape (subspherical to cuneat) and dimension (shortest diameter 10 μm, longest diameter to 30 μm), monoporate, surface of cells psilate to scabrate, dark redish-brown colour. zag-6 multicellular fungal palynomorph with seven cells, iregular in shape (subspherical to cuneat) and dimension (shortest diameter 7 μm, longest diameter to 12 μm), aporate, surface smooth, translucentbrown colour. zag-7 multicellular fungal palynomorph, probably conidia; total lengh 70 μm; cells irregular in shape (subspherical to rectangular), with diameter < 10 μm; brown colour. zag-8 multicellular fungal palynomorph with seven cells; total lengh 40 x 30 μm; cells irregular in shape (mostly rectangular), approx. 10 to 15 μm in lenght; surface smooth; brown colour. zag-9 probably fungal palynomorph; multicelular; total lengh 40 x 25 μm; cells irregular in shape (mostly rectangular), approx. 5 to 15 μm in lenght; surface smooth; reddish. zag-10 multicellular fungal palynomorph, ascospores or conidia; total lengh 70 x 30 μm; cells irregular in shape (mostly rectangular to cuneat), approx. 5 to 15 μm in lenght; surface smooth, translucent-brown colour. zag-11 multicellular fungal palynomorph with 16 cells, tapering to a point at one end of axi, triserial, linear; each cell irregular in shape (subspherical to rectangular) and dimension (shortest diameter 8 μm, longest diameter 26 μm) with total length of filament 90 μm; surface smooth to psilate; dark brown colour. zag-12 multicellular fungal palynomorph with 14 cells, tapering to a point at one end of axi, curved; cells mostly rectangular in shape with dimension 5-7.5 x 7.5-10, triangular to a point end of axi; reddish. zag-13 multicellular fungal palynomorph with 20 cells, very similar to zag-12 but always found without end of axi; cells mostly rectangular in shape and slightly larger than zag-12 with dimension 7.5-10 x 12-15 μm, triangular at the bend of the structure; reddish. zag-14 fungal spore measuring 32 x 25 μm; cylindrical-subfusiform in shape; heteropolar, truncate at the basal side and apical at the end, with two narrow arched pores; brown. zag-15 fungal spore from class sordariomycetes, measuring 45 × 35 μm; cylindrical in shape; heteropolar, truncate at the basal side and apical at the end, with no visible pore; brown. zag-16 multicellular fungal conidia; dimension 70 x 55 μm; cells irregular in shape, mostly rectangular; each cell approx. 12 x 10 μm, inaperturate; surface smooth, translucent-brown colour. zag-17 multicellular fungal palynomorph, always incomplete, probably remains of conidia; cells irregular in shape, mostly rectangular, trapezoidal or pentagonal; each cell approx. 15-20 x 10-12 μm, inaperturate; surface smooth, translucent-brown colour. zag-18 unbranched hyphae, long-septate. zag-19 branched hyphae, short-septate. zag-20 microfossil hyaline, globose, 25 μm in diameter, ornamented with numerous, densely arranged, anastomosing processes; similar to hdv-989 (carrión & van geel, 1999) but smaller. zag-21 globose spores of unknown origin; dimension 25 μm in diameter, protruding spines 7,5-10 μm long; reddish; similar to hdv-182 (van geel et al., 1983; carrión & navarro, 2002) but slightly bigger, with less visible reticulum. zag-22 globose spores of unknown origin; dimension 20 μm in diameter, protruding spines 5-7,5 μm long; brown; similar to hdv-182 (van geel et al., 1983; carrión & navarro, 2002) but with less visible reticulum. zag-23 probably resting egg of unknown origin, dimension 90 x 55 μm; muri made irregular surface pattern; yellow colour. figure 4. the proportion of various ecological indicators based on counted palynomorphs within 100 lycopodium spores in each analysed sample: indicators of wetness (alnus, trilete, antocerotidae, riccia, assulina, hdv-225, hdv-984, hdv-989, zag-20), erosion/desiccation indicators (glomus, hdv-200, uab-7, uab-48, chomotriletes), anthropogenic indicators (senecio, xanthium, convolvulus arvensis, cerealia, hdv-351), unknown (almost all newly described palynomorphs and other pollen and npps not included in the any abovementioned categories). g eo lo gi a c ro at ic a 258 geologia croatica 77/3 abundance (suppl. 2) and concentration values (suppl 3). indicators of erosion/dessication prevailed, and indicators of wetness were rare (fig. 4). the gt-3 (47-57 cm) sample contains 5,504 pollen grains/g, 44,035 npps/g and 4.161,326 charcoal particles/g (suppl. 3). within nap only xanthium t. was observed while ap is completely missing. the most abundat npp is glomus, reaching here the highest value in comparison with others samples (suppl. 2). charcoal particles were numerous (suppl. 3). indicators of erosion/dessication prevailed, and indicators of anthropogenic influence were sparsely presented (fig. 4). sample gt-4 (70-80 cm) contains 8,257 pollen grains/g, 33,026 npps/g and 404,573 charcoal particles/g (suppl. 3). within ap, only pinus and tilia were observed, nap is missing and local vegetation is presented by antocerotidae. npps were not abundant, albeit with the relative domination of chomotriletes, fungal tissue and uab­7 (suppl. 2). charcoal particles were rare (suppl. 3). palynomorphs of unknown ecological value prevailed, succeeded by indicators of erosion/ dessication and wetness (fig. 3). the gt-4 (30-40 cm) sample contains 38,531 pollen grains/g, 165,132 npps/g and 1.857,735 charcoal particles/g (suppl. 3). within ap, only pinus was observed. the nap spectrum includes senecio t., convolvulus arvensis and cerealia, while the local vegetation includes undifferentiated trilete spores, antocerotidae and riccia spores. within npps, chomotriletes is the most abundant, succeeded by fungal tissue, hdv-200 and hdv-984. additionaly, two epicoccum spores were counted. the amoebae assulina was only observed in this sample (suppl. 2). charcoal particles were numerous (suppl. 3). only this sample contains all four ecological categories. indicators of erosion/dessication are relatively dominant, succeeded by palynomorphs of unknown ecological value. indicators of wetness were represented in a greater proportion than anthropogenic ones (fig. 4). sample gt-6 (105-110 cm) lacks any pollen grains. npps concentration is 5,504 per gram, and chracoal concentrations is 1.588,019 particles per gram (suppl. 2). within the palynomorphs only chomotriletes was observed (suppl. 2). charcoal particles were numerous (suppl. 3). due to the lack of other proxies, palaeoecological trends were unclear. the gt-6 (55-60 cm) sample contains 5,504 pollen grains/g, 101,831 npps/g and 4.981,482 charcoal particles/g (suppl. 3). within ap, only corylus was observed. chomotriletes was the most abundant npp (suppl. 2). charcoal particles were very numerous (suppl. 3). indicators of erosion/ dessication were relatively dominant (fig. 4). 4. discussion 4.1. core-specific interpretation of the palaeoenvironment gt-1 core the lower part of the core (from 158-168 cm) is characterized by the absence of erosion/dessication indicators, with only one chomotriletes observed. van de schootbrugge et al. (2024) concluded that chomotriletes is the valid senior synonym of a variety of taxa, including pseudoschizaea and concentricystes. they considered it a freshwater organism cyst, dominant in floodplain soils and ephemeral freshwater lakes. the appearance of hazel pollen (corylus) coincides with the fungus hdv-35, which is usually associated with an anthropogenic presence in a particular area (van geel et al., 1981). however, the number of charcoal particles is relatively low. some authors (pyne et al., 1996) have shown that in fires with low burning intensity (under conditions of increased humidity), more charcoal particles are released. the presence of hazel may indicate slightly drier conditions in the lower part of the core. the topmost layers of the core (50-60 cm and 60-70 cm depths) contain individual pollen grains of oak (quercus robur-pubescens t.) and alder (alnus), pollen taxa common in the plain area of central croatia (hruševar et. al., 2020, 2023) within flooding soil and high groundwater levels. the presence of the glomus fungus and the high frequency of the non­pollen palynomorph chomotriletes (previously pseudoschizaea) indicate pronounced erosion processes (scott, 1992; carrión et al., 2018; brisset et al., 2020), possibly caused by increased fire activity. namely, within all of the analysed samples, this one is characterized by the highest charcoal concentration. the fungus hdv­200, which is common in the sediment formed by the decomposition of helophytes at the bottom of water pools during dry periods (van geel et al., 1989), further supports the indication that conditions of alternating humidity were pronounced. gt-3 core xanthium pollen was observed in the sample, a species that may indicate livestock breeding/grazing (tonkov et al., 2011). however, the finding of this secondary anthropogenic indicator is not further strengthened by non­pollen palyno­ morphs that would additionally confirm human influence. charcoal particles were abundant. gt-4 core pollen indicators of anthropogenic activity are absent from the lower sample (70-80 cm), and indicators of wetness are scarce, although an antocerotidae moss spore was observed. within arboreal pollen, pine (pinus) and lime (tilia) are represented. both taxa have a high proportion of sporopollenin in the exine which makes them resistant to non-wrapping conditions of preservation (traverse, 2007), hence the reason they don’t reflect the prevalent vegetation. the higher abundance of fun­ gal hyphae and tissues, accompanied by epicoccum spores probably reflects more drier conditions. the upper sample (30-40 cm) contains the most species rich pollen spectrum within the analysed samples. observed palynomorphs indicate the existence of a temporary oligo­ trophic water body, accompanied by indicators of erosion/des­ iccation (chomotriletes). water mosses riccia and antocer­ otidae, which grows on wet habitats, were represented by their spores, accompanied by hdv-225, hdv-984 and hdv-989, probably of algae origin. at the same time, it is the only sam­ ple in which an amoeba, more specifically assulina muscorum, was observed. the aforementioned amoeba is an indicator of oligotrophic habitats with a lower ph substrate (van geel et al., 1989; fiłoc & kupryjanowicz, 2015). all this in­ g eologia c roatica 259hruševar et al.: the role of pollen and npp research in palaeoenvironmental reconstruction of the neolithic archaeological site “gorjani-topole” ... dicates that conditions for preservation were somewhat more favourable than in other samples. within plants, pollen of the field bindweed (convolvulus arvensis) and one pollen grain of cereals (cerealia) were observed. only grass pollen > 37 µm were considered as cultivated grass (eg. dörfler, 2013). considering that some of the largest wild grasses pollen, such as glyceria t., bromus hordeaceus t. (waller et al., 2017) and arrhenatherum t. (tweddle et al., 2005) can easily be mistaken for cereals, the annulus diameter assessment was also taken into account. both taxa indicate the presence of humans and anthropo­ genic pressure on the studied area. moreover, riccia moss is often found in water bodies exposed to grazing (carrión & navarro, 2002), similar to some taxa of anthoceros which could be linked with anthropogenic pressure (kozáková et al., 2015). among the fungi, epicoccum spores were observed. this is a common invasive taxa on crops (fatima et al., 2016) although they can be found on different materials, even in marine organisms (fatima et al., 2016; piecuch et al., 2020). gt-6 core the sample at a depth of 105-110 cm cannot be interpreted, even indirectly, due to the poor preservation of the palyno­ morphs. the near-surface sample of this core (depth section 55-60 cm) contains individual pollen grains of hazel (corylus), a shrub species that appears as a pioneer due to fire and can indicate the presence of people in an area (mithen et al., 2001; groß et al., 2018). a very high concentration of charcoal particles can support anthropogenic activity, and perhaps fire is the cause of increased erosion, which is reflected in the high number of chomotriletes indicators. 4.2. palaeoecological history in the continental biogeographical region of croatia, recon­ struction of vegetation with an emphasis on changes in plant cover, was possible only for the area of central croatia where peatlands occur (hruševar et al., 2020, 2023), while in eastern croatia such data are mostly missing. for this reason, archaeological excavations provide a great possibility for understanding plant cover and changes in the vegetation of the slavonia region (bakrač et al., 2015), although they usually refer to a very local area or short time period. however, all the analysed samples collected from four cores (gt-1, gt-3, gt-4, gt-6) were poor in palynomorphs, (suppl. 2) and none of them reach statistical significance of approximately 300 to 1,000 grains in order to ensure the statistical robustness of the pollen percentages (kneller, 2009). in this example, even the counts below 150 pollen grains, proposed by some other authors (lytle & wahl, 2005; keen et al., 2014; djamali & cilleros, 2020) were not achieved and without the statistically significant pollen sum, the plant cover of the studied site and vegetation changes cannot be meaningfully interpreted. as the pollen spectrum is reduced in terms of both the qualitative (different pollen types observed) and quantitative (the number of palyno­ morphs counted) analysis, it is only possible to indicate palaeoecological trends and partially interpret them (suppl. 2, fig. 4), considering the indicator value of the few preserved palynomorphs. within ap the presence of tilia, quercus and corylus was expected in mixed oak deciduous forests, where oaks, elms, limes, ash and hazel were predominant at low to mid elevations during most of the holocene (feurdean et al., 2011; tanţău et al., 2006). the presence of alnus and corylus (tinner et al., 2000) or quercus and corylus (jamrichová et al., 2017) could be favoured by fire. this fits well with our samples, where charcoal particles are common. hazel was also used as food resources by mesolithic (kuneš et al., 2008; regnell, 2012) and neolithic communities (marinova et al., 2013) frequently colonizing humid lowlands previously used for crops and pasture (pèlachs et al., 2009). there is evidence of its promotion by the mesolithic people. they removed shade­tolerant trees (mithen et al., 2001) or expanded hazel by selective pruning for greater nut yield production (groß et al., 2018). moreover, cattle grazing could increase the ratio of light demanding hazel (kolář et al., 2018) and promote this taxon at the expense of tilia because its leaves are less palatable (haeggström, 1990). all nap types belong to anthropogenic indicators. the finding of cerealia pollen, a primary anthropogenic indicator (behre, 1981, feurdean et al., 2013; mercuri et al., 2013) and convolvulus arvensis, a weedy taxa (hulina, 1998) in summer cereals and root crops and/or fallow land (behre, 1990) is of great significance. both taxa indicate agricultural activity within the research area. within asteraceae xanthium t. (tonkov et al., 2011) and senecio t. could be considered as anthropogenic indicators. the latter is also frequently found as an indicator of wet communities (hájková et al., 2013), as it includes a great number of different species and many genera of the subfamily asteroideae (beug, 2015). despite the fact that senecio t. also appears in natural communities or shows no significant relationship between its occurrence and archaeological sites in more recent publications (abraham et al., 2023), we consider it here as a synanthropogenic taxon, in the sense of latałowa (1992), kuneš et al. (2015) and servera-vives et al. (2023). although the received ap and nap pollen spectra indicate possible anthropogenic pressure, these taxa are also part of the natural vegetation in the studied area, and their findings perhaps explain taphonomic processes better than providing evidence of human influence. due to the lack of pollen in the analysed samples, npps can be of great importance for palaeoenvironmental interpretation (eg. shumilovskikh et al., 2016; enevold et al., 2019.; druzhinina et al., 2023). qualitative analysis of npps indicates the greatest diversity of fungal spores in our samples, which was partly expected due to their better preservation in soil compared to some other microfossils (shumilovskikh & van geel, 2020). numerous new types were observed (zag-4 to zag-23) albeit their indicator values are unknown. quantitative analysis indicates the largest number of the palynomorph chomotriletes, considered to be an alga (pèlachs et al., 2009). also, chomotriletes is an indicator of erosion and periodic drying of the substrate (scott, 1992; carrión et al. 2018; brisset et al., 2020). along with this palynomorph, glomus, hdv­200, uab­7, uab-48 could indicate erosion/dessication processes g eo lo gi a c ro at ic a 260 geologia croatica 77/3 (revelles et al., 2016; brisset et al., 2020). palynomorphs of probable algal origin including hdv-225 (van geel et al., 1989; kuhry, 1997), hdv-984 (carrión & van geel, 1999), which likely belongs to the genus euastrum, and to the latter very similar hdv-989 (carrión & van geel, 1999) are used here as indicators of wetness. the occurrence of hdv­ 351 during human habitation has been recorded by van geel et al. (1981) and miola et al. (2010). as npps represent a large group of the resistant remains of a taxonomically wide variety of organisms, (shumilovskikh & van geel, 2020) their determination is often difficult. even though they are providing a very local palaeoenvironmental signal, and are considered as very useful indicators, their individual findings, in our study site, must be taken with caution. enevold et al. (2019) highlighted that many of the npp types are rare with random occurrences so that only the more frequent types may be useful and informative. all charcoal particles were insufficiently large (< 250 μm) to be considered indicators of local fires (olsson et al., 2010; burrows et al., 2014), and can be considered as evidence of burning in the broader area of sediment sampling (feurdean et al., 2015; adolf et al., 2018). although the increased number of fire indicators is related to anthropogenic pressure, no signs of human activity were observed in the sample with the highest concentration of charcoal particles eg. gt-1 (50-60 cm). additionaly, in the two samples with a high concentration of charcoal particles, eg. gt-6 (55-60 cm) and gt -3 (47-57 cm), the former is completely free of anthropogenic indicators, and in the latter, only the clotbur pollen (xanthium), a secondary anthropogenic indicator (tonkov et al., 2011), was observed. 4.3. taphonomic processes a low number of palynomorphs or their absence is generally a consequence of sedimentological processes and the existing geochemistry and/or climate that does not support the preservation of microand/or macro-plant remains, and such conditions in the sediment are often the result of the interaction of landscape and climate (gastaldo & demko, 2011). peatlands and lake sediments are considered the most favourable habitats for palaeoenvironmental reconstructions (godwin, 1981; moore et al., 1991), while wet/swampy habitats, exposed to periodic drying, are considered unfavourable. namely, the wetting and drying of the substrate leads to changes in oxic and anoxic conditions, which can result in an increased rate of decomposition of organic matter (carbon recycling) and a drop in the ph value of the sediment, which is why wetland habitats, although favourable in principle, often prove to be "challenging" for palynological research (gastaldo et al., 1989; gastaldo & demko, 2011). although loess sediments could be good archives of palynomorphs used for palaeoenvironment reconstruction (shang & li, 2010) loess­palaeosol sequences deposited under an oxidizing environment are mostly unfavourable for the reconstruction and interpretation of vegetational changes (moore et al., 1991; zhang et al., 2017), due to oxidation, microbial activity, possible high ph and deterioration of pollen grains (zelikson, 1995; zhang et al., 2017). in this sense, it can be concluded that all the analysed (sub)samples were exposed to unfavourable processes of biostratinomy and/or diagenesis, which is why only palynomorphs with a higher proportion of sporopollenin, such as the pollen of pine (pinus), lime (tilia) and the aster family (senecio, xanthium) or trilete plant spores were the only types preserved (jacobson & bradshaw, 1981; traverse, 2007) in sediment, truncating the pollen spectrum. this is especially expected in loess and loess-like sediments, where asteraceae pollen (zelikson, 1995) including artemisia, aster, taraxacum (zhang et al., 2017), chenopodiaceae (zelikson, 1995; zhang et al., 2017) and pinus (zhang et al., 2017) were mostly overrepresented in the pollen spectra. high sporopollenin content in the exines of pinus, tilia, corylus, alnus, cichoriaceae and asteraceae (havinga, 1964) makes the finding of this pollen type expected in the study site. in contrast, grazing areas with animal breeding practices are often characterised by asteraceae (including asteroideae and cichorioideae) and chenopodiaceae nap types, (mazier et al., 2006; feurdean et al., 2013; florenzano et al., 2013; rattighieri et al., 2013; kozáková et al., 2015), which highlight difficulties in interpretation (anthropogenic vs. taphonomic influence) when pollen spectra are low. although npps can be found in any type of sediment (shumilovskikh & van geel, 2020) the comparative impact of taphonomic processes on their preservation has not been investigated in detail. still, microfossils composed of chitin (fungal palynomorphs, microforaminifers and scolecodonts) may be very well preserved in sediments, recording past sedimentation conditions (medeanic et al., 2011; shumilovskikh & van geel, 2020). according to shumilovskikh & van geel (2020) helminths eggs, insect fragments, fungi, fabers and unknown npps are most frequent in analysed soil samples on a global level. this is in accordance with our findings that npps in loess samples presented with a higher concentration and diversity (both qualitatively and quantitatively) in comparison with pollen palynomorphs, while the preservation potential of charred particles (charcoals) is even higher (bryant & holloway, 2009). 5. conclusions the low number of different pollen taxa and their individual appearance prevents plant cover reconstruction or interpretation of vegetational change during the neolithic sopot cultural layer in eastern croatia. however, all pollen taxa belong to mixed oak forests which is in agreement with the expected planar vegetation of the continental biogeographical region during the middle holocene. the appearance of cereal pollen, as a primary anthropogenic indicator, highlighted the human impact in the studied site, even though the rest of the observed weedy taxa probably reflect the poor preservation conditions in the soil samples (only taxa with higher sporopollenin contents were preserved). the analysed loess and loess-like sediments were better archives of npps than of pollen, showing a versatile abundance of algae, fungi and unknown npps. for this reason, g eologia c roatica 261hruševar et al.: the role of pollen and npp research in palaeoenvironmental reconstruction of the neolithic archaeological site “gorjani-topole” ... interpretation of the palaeoenvironmental trends in the studied archaeological site were based more on the indicative ecological value of npps than pollen taxa, making possible a distinction between wetter, dynamic (erosion/dessication) or anthropogenic paleoenvironments. charcoal particles probably reflects the regional fire history. acknowledgment we would like to thank josip barbača for the fieldwork, dragica kovačić and antun škrtić for laboratory work and nikola belić for technical assistance. we also thank the reviewers for all of the constructive comments that improved this paper. funding this research was funded by the croatian science foundation, ip-2019-04-5344. references abraham, v., macek, m., tkáč, p., novákl d., pokorný, p., kozáková, r., jamrichová, e., soukupová, m.g. & kolář, j. (2023): pollen anthropogenic indicators revisited using large-scale po­ llen and archaeological datasets: 12,000 years of human-vegetation inte­ ractions in central europe.– preslia, 95, 385–411. doi: 10.23855/pre­ slia.2023.385 adolf, c., wunderle, s., colombaroli, d., weber, h., gobet, e., heiri, o., leeuwen, j.f., bigler, c., connor, s.c., gałka, m., mantia, t.l., makhortykh, s., svitavská-svobo­ dová, h., vannière, b. & tinner, w. (2018): the sedimentary and remote-sensing reflection of biomass burning in europe.− global ecology and biogeography, 27, 199–212. doi:10.1111/geb.12682 andrič, m. (2007): why were the neolithic landscapes of bela krajina and ljubljana marshes regions of slovenia so dissimilar.− documenta prae­ historica, 34, 177–189. doi: 10.4312/dp.34.13 anonymous (2017): informacija o stanju, gospodarenju i zaštiti šuma na području osječko-baranjske županije [information on the condition, management and forests protection in the area of osijek-baranja county – in croatian].– republic of croatia, osijek-baranja county, osijek.. bakels, c. (2020): pollen and archaeology.− in: henry, a.g. (ed.): han­ dbook for the analysis of micro-particles in archaeological samples, springer nature switzerland, cham, switzerland, 203–224. doi: 10.1007/978-3-030-42622-4_9 bakrač, k., krznarić škrivanko, m., miko, s., ilijanić, n. & hasan, o. (2015): first palynological results from the archaeological site sopot, croatia.− geologia croatica, 68/3, 303–311. doi: 10.4154/ gc.2015.23 behre k.-e. (1981): the interpretation of anthropogenic indicators in pollen diagrams.− pollen et spores, 23, 225–245. behre, k.-e. (1990): impact of prehistoric and medieval man on the vege­ tation.− in: hicks, s. & moe, d. (eds): man at the forest, limit. pact 31, belgium. beug, j.-h. (2015): leitfaden der pollenbestimmung für mitteleuropa und angrenzende gebiete.– verlag dr. friedrich pfeil: münchen, germany, 542 p. brisset, e., revelles, j., expósito, i., bernabeu aubán, j. & burjachs, f. (2020): socio-ecological contingencies with climate changes over the prehistory in the mediterranean iberia.− quaternary, 3/3, 1–19. doi: 10.3390/quat3030019 bryant, v.m. & holloway, r.g. (2009): reducing charcoal abunda nce in archaeological pollen samples.− palynology, 33/2, 63–72. doi: 10.2113/gspalynol.33.2.63 burrows, m.a., fenner, j. & haberle, s.g. (2014): testing peat humification analysis in an australian context: identifying wet shifts in regional climate over the past 4000 years.− mires and peat, 14, 1–19. carrión, j.s. & navarro, c. (2002): cryptogam spores and other non-pollen microfossils as sources of palaeoecological information: ca­ se-studies from spain.− annales botanici fennici, 39, 1–14. carrión, j.s. & van geel, b. (1999): fine-resolution upper weichselian and holocene palynological record from navarrés (valencia, spain) and a discussion about factors of mediterranean forest succession.− review of palaeobotany and palynology, 106, 3–4, 209-236. doi: 10.1016/s00346667(99)00009-3 carrión, j.s., fierro, e., ros, m., munuera, m., fernández, s., ochando, j., amorós, g., navarro, f., rodríguez estrella, t., manzano, s., gonzález-sampériz, p. & mo­ reno, a. (2018): ancient forests in european drylands: holocene pa­ laeoecological record of mazarrón, south-eastern spain.− proceedings of the geologists' association, 129, 512–525. doi: 10.1016/j.pgeo­ la.2018.05.007 court-picon, m., buttler, a. & de beaulieu, j.l. (2006): modern pollen/vegetation/land-use relationships in mountain environments: an example from the champsaur valley (french alps).− vegetation history and archaeobotany, 15, 151–168. doi: 10.1007/s00334-005-0008-8 dietre, b., walser, c., kofler, w., kothieringer, k., hajdas, i., lambers, k., reitmaier, t. & haas, j.n. (2016): neolithic to bronze age (4850–3450 cal. bp) fire management of the alpine lower engadine landscape (switzerland) to establish pastures and cereal fields.− the holocene, 27, 181–196. doi: 10.1177/0959683616658523 djamali, m. & cilleros, k. (2020): statistically significant minimum pollen count in quaternary pollen analysis; the case of pollen-rich lake sediments.− review of palaeobotany and palynology, 275, 104–156. doi: 10.1016/j.revpalbo.2019.104156 dörfler, w. (2013): prokoško jezero: an environmental record from a su­ balpine lake in bosnia-herzegovina.– in: müller, j., rassmann, k. & hofmann, r. (eds.): okolište 1 – untersuchungen einer spätne­ olithischen siedlungskammer in zentralbosnien.− universitätsforschun­ gen zur prähistorischen archäologie, dr. rudolf habelt gmbh, bonn, 228, 311–340. doyen, e. & etienne, d. (2017): ecological and human land-use indicator value of fungal spore morphotypes and assemblages.− vegetation history and archaeobotany, 26, 357–367. doi: 10.1007/s00334-016-0599-2 druzhinina, o., hruševar, d., van den berghe, k.j., de jo­ ng-lambregts, n., golyeva, a., bakrač, k. & mitić, b. (2023): application of phytolith (microbiomorphic) and non-pollen palynomorph analyses to the geoarchaeological study of the graft far­ myard, the netherlands.− interdisciplinaria archaeologica, 14/1, 105– 117. doi: 10.24916/iansa.2023.1.8 enevold, r., rasmussen, p., løvschal, m., olsen, j. & od­ gaard, b.v. (2019): circumstantial evidence of non-pollen palyno­ morph palaeoecology: a 5,500 year npp record from forest hollow sediments compared to pollen and macrofossil inferred palaeo­ environments.− vegetation history and archaeobotany, 28, 105–121. doi: 10.1007/s00334-018-0687-6 faegri, k. & iversen, j. (1989): textbook of pollen analysis. (4th edition by faegri, k., kaland, p.e. & krzywinski, k.).− john wiley & sons new york, 328 p. fatima, n., ismail, t., muhammad, s.a., jadoon, m., ahmed, s., azhar, s. & mumtaz, a. (2016): epicoccum sp., an emerging source of unique bioactive metabolites.− acta poloniae pharmaceutica, 73/1, 13–21. feurdean, a., gałka, m., kuske, e., tanţău, i., lamentowicz, m., florescu, g., liakka, j., hutchinson, s., mulch, a. & hickler, t. (2015): last millennium hydro-climate variability in cen­ tral–eastern europe (northern carpathians, romania).− the holocene, 25/7, 1179–1192. doi: 10.1177/0959683615580197 feurdean, a., parr, c.l., tanţău, i., fărcaş, s., marinova, e. & perşoiu, i. (2013): biodiversity variability across elevations in the carpathians – parallel change with landscape openness and land use.− the holocene, 23/6, 869–881. doi: 10.1177/095968361247 g eo lo gi a c ro at ic a 262 geologia croatica 77/3 feurdean, a., tanţău, i. & fărcaş, s. (2011): holocene variability in the range distribution and abundance of pinus, picea abies, and quercus in romania: implications for their current status.− quaternary science reviews, 30, 3060–3075. doi: 10.1016/j.quascirev.2011.07.005 fiłoc, m. & kupryjanowicz, m. (2015): non-pollen palynomorphs cha­ racteristic for the dystrophic stage of humic lakes in the wigry national park, ne poland.− studia quaternaria, 32/1, 31–41. doi: 10.1515/ squa-2015-0003 florenzano, a., mercuri, a.m. & carter, j.c. (2013): economy and environment of the greek colonial system in southern italy: pollen and npps evidence of grazing from the rural site of fattoria fabrizio (viiv cent. bc; metaponto, basilicata).− annali di botanica, 3, 173–181. doi: 10.4462/annbotrm-10248 gastaldo, r.a., bearce, s.c., degges, c., hunt, r.j., peebles, m.w. & violette, d.l. (1989): biostratinomy of a holocene oxbow lake: a backswamp to mid-channel transect.− review of palaeobotany and palynology, 58, 47–60. doi: 10.1016/0034-6667(89)90056-0 gastaldo, r.a. & demko, t.m. (2011): the relationship between con­ tinental landscape evolution and the plant-fossil record: long term hydrologic controls on preservation.− in: allison, p.a. & bottjer, d.j. (eds.): taphonomy process and bias through time (2nd edition), springer, dordrecht, 249-285. godwin, h. (1981): the archives of the peat bogs.– cambridge university press, cambridge. groß, d., lübke, h., schmölcke, u. & zanon, m. (2018): early me­ solithic activities at ancient lake duvensee, northern germany.− the holocene, 29, 197–208. doi: 10.1177/0959683618810390 haeggström, c.a. (1990): the influence of sheep and cattle grazing on wooded meadows in åland, sw finland.− acta botanica fennica, 141, 1–24. hájková, p., jamrichová, e., horsák, m. & hájek, m. (2013): ho­ locene history of a cladium mariscus­dominated calcareous fen in slo­ vakia: vegetation stability and landscape development.− preslia, 85, 289– 315. havinga, a.j. (1964): investigation into the differential corrosion suscepti­ bility of pollen and spores.− pollen et spores, 6, 621–635. hruševar, d., bakrač, k., miko, s., ilijanić, n., šparica miko, m., hasan, o. & mitić, b. (2023): vegetation history in central cro­ atia from ~10,000 cal bc to the beginning of common era – filling the palaeoecological gap for the western part of south­eastern europe (we­ stern balkans).− diversity, 15, 235. doi: 10.3390/d15020235 hruševar, d., bakrač, k., miko, s., ilijanić, n., hasan, o., ma­ mić, m., puljak, t., vucić, a., husnjak malovec, k., we­ ber, m. & mitić, b. (2020): environmental history in central croatia for the last two millennia – vegetation, fire and hydrological changes un­ der climate and human impact.− prilozi instituta za arheologiju u zagre­ bu, 37, 117–164. doi: 10.33254/piaz.37.5 hulina, n. (1998): korovi.– školska knjiga, zagreb, 222 p. jacobson, g.l.jr. & bradshaw, r.h.w. (1981): the selection of sites for paleovegetational studies.− quaternary research, 16, 80–96. doi: 10.1016/0033-5894(81)90129-0 jamrichová, e., hédl, r., kolář, j., tóth, p., bobek, p., hajna­ lová, m., procházka, j., kadlec, j. & szabó, p. (2017): human impact on open temperate woodlands during the middle holocene in central europe.− review of palaeobotany and palynology, 245, 55-68. doi: 10.1016/j.revpalbo.2017.06.002 kalafatić, h., šiljeg, b. & šošić klindžić, r. (2021): filling the network gaps: bračevci – bašćine, new neolithic circular enclosure and medieval village.− annales instituti archaeologici, 17/1, 8–16. karpińska-kołaczek, m., kołaczek, p. & stachowi­ cz-rybka, r. (2014): pathways of woodland succession under low hu­ man impact during the last 13,000 years in northeastern poland.− qua­ ternary international, 328–329, 196–212. doi: 10.1016/j.quaint.2013.11.038 keen, h.f., gosling, w.d., hanke, f., miller, c.s., montoya, e., valencia, b.g. & williams, j.j. (2014): a statistical sub-sampling tool for extracting vegetation community and diversity information from pollen assemblage data.− palaeogeography, palaeoclimatology, palaeo­ ecology, 408, 48–59. doi: 10.1016/j.palaeo.2014.05.001. klepo, m. (2020): službeni glasnik grada đakova [official gazette of the city of đakovo – in croatian], 21, 1–105, đakovo. kneller, m. (2009). pollen analysis.− in: gornitz, v. (ed.): encyclope­ dia of paleoclimatology and ancient environments.– encyclopedia of earth sciences series, springer, dordrecht, 819 p. doi: 10.1007/978-14020-4411-3_192 kolář, j., kuneš, p., szabó, p., hajnalová, m., svitavská svo­ bodová, h., macek, m. & tkáč, p. (2018): population and forest dynamics during the central european eneolithic (4500–2000 bc).− ar­ chaeological and anthropological science, 10, 1153–1164. doi: 10.1007/ s12520-016-0446-5 korolija, b. & jamičić, d. (1989a): osnovna geološka karta sfrj 1:100000, list našice l34–85 [basic geological map of sfry 1:100000, našice sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. korolija, b. & jamičić, d. (1989b): osnovna geološka karta sfrj 1:100000. tumač za list našice l34–85 [basic geological map of sfry 1:100000, geology of the našice sheet – in croatian].– geološki zavod, savezni geološki zavod, beograd, 45p. kozáková, r., pokorný, p., peša, v., danielisová, a., ču­ láková, k. & svitavská svobodová, h. (2015): prehistoric human impact in the mountains of bohemia. do pollen and archaeologi­ cal data support the traditional scenario of a prehistoric “wilderness”?− review of palaeobotany and palynology, 220, 29–43. doi: 10.1016/j. revpalbo.2015.04.008 kuhry, p. (1997): the palaeoecology of a treed bog in western boreal cana­ da: a study based on microfossils, macrofossils and physico-chemical properties.− review of palaeobotany and palynology, 96,183-224. doi: 10.1016/s0034-6667(96)00018-8 kulkarni, c., peteet, d., boger, r. & heusser, l. (2016): explo­ ring the role of humans and climate over the balkan landscape: 500 years of vegetational history of serbia.− quaternary science reviews, 144, 83–94. doi: 10.1016/j.quascirev.2016.05.021 kuneš, p., pokorný, p. & šída, p. (2008): detection of the impact of ear­ ly holocene hunter­gatherers on vegetation in the czech republic, using multivariate analysis of pollen data.− vegetation history and archaeo­ botany, 17, 269–287. doi: 10.1007/s00334-007-0119-5 kuneš, p., svobodová-svitavská, h., kolář, j., hajnalová, m., abraham, v., macek, m., tkáč, p. & szabó, p (2015): the origin of grasslands in the temperate forest zone of east-central europe: long-term legacy of climate and human impact.– quaternary science reviews, 116, 15–27. latałowa, m. (1992): man and vegetation in the pollen diagrams from wolin island (nw poland).− acta palaeobotanica, 32, 123–249. lehmkuhl, f., nett, j.j., pötter, s., schulte, p., sprafke, t., jary, z., antoine, p., wacha, l., wolf, d., zerboni, a., ho­ šek, j., marković, s.b., obreht, i., sümegi, p., veres, d., zeeden, c., boemke, b., schaubert, v., viehweger, j. & hambach, u. (2021): loess landscapes of europe – mapping, geo­ morphology, and zonal differentiation.− earth-science reviews, 215, 103496. doi: 10.1016/j.earscirev.2020.103496 leko, m. (2016): šumska vegetacija šireg područja oko jezera borovik. [forest vegetation of the wider area around lake borovik – in croatian].– unpublish undergraduate thesis, faculty of forestry, university of za­ greb, 21p. lytle, d.e. & wahl, e.r. (2005): palaeoenvironmental reconstructions using the modern analogue technique: the effects of sample size and decision rules.− the holocene, 15, 554–566. doi: 10.1191/0959683605hl830rp. maher, l.j. (1981): statistics for microfossil concentration measurements employing samples spiked with marker grains.– review of palaeobotany and palynology, 32, 153–191. doi: 10.1016/0034-6667(81)90002-6 marinova, e., filipović, d., obradović, d. & allué, e. (2013): wild plant resources and land use in mesolithic and early neolithic so­ uth-east europe: archaeobotanical evidence from the danube catch­ ment of bulgaria and serbia.− offa, 69-70, 467–478. g eologia c roatica 263hruševar et al.: the role of pollen and npp research in palaeoenvironmental reconstruction of the neolithic archaeological site “gorjani-topole” ... mazier, f., galop, d., brun, c. & buttler, a. (2006): modern pollen assemblages from grazedvegetation in the western pyrenees, france: a numerical tool for more precise reconstruction of past cultural landsca­ pes.− the holocene, 1, 91–103. doi: 10.1191/0959683606hl908rp medeanic, s., zamora, n., & corrêa, i.c. (2011): non-pollen palyno­ morphs as environmental indicators in the surface samples from man­ grove in costa rica.− revista geológica de américa central, 39, 27–51. doi: 10.15517/rgac.v0i39.12246 mercuri, a.m., bandini mazzanti, m., florenzano, a., mon­ tecchi, m., rattighieri, e. & torri, p. (2013): anthropogenic pollen indicators (apii) from archaeological sites as local evidence of human-induced environments in the italian peninsula.− annali di bota­ nica, 3, 143–153. doi: 10.4462/annbotrm-10316 miola, a. (2012): tools for non-pollen palynomorphs (npps) analysis: a list of quaternary npp types and reference literature in english langu­ age (1972–2011).− review of palaeobotany and palynology, 186, 142–161. doi: 10.1016/j.revpalbo.2012.06.010 miola, a., favaretto, s., sostizzo, i., valentini, g. & asioli, a. (2010): holocene salt marsh plant communities in the north adriatic coastal plain (italy) as reflected by pollen, non-pollen palynomorphs and plant macrofossil analyses.− vegetation history and archaeobotany, 19, 513–529. doi: 10.1007/s00334-010-0267-x mithen, s., finlay, n., carruthers, w., carter, s. & ashmore, p. (2001): plant use in the mesolithic: evidence from staosnaig, isle of colonsay, scotland.− journal of archaeological science, 28, 223–234. doi: 10.1006/jasc.1999.0536 mooney, s.d. & tinner, w. (2011): the analysis of charcoal in peat and organic sediments.− mires and peat, 7/9, 1–18. moore, p.d., webb, j.a. & collinson, m. (1991): pollen analysis (2nd edition).− blackwell sci. publication, london, 216 p. njegač, d. (2002): istočna hrvatska [eastern croatia – in croatia].– in: borovac, i. (ed.): veliki atlas hrvatske. mozaik knjiga, zagreb, 511 p. olsson, f., gaillard, m., lemdahl, g., greisman, a., lanos, p., marguerie, d., marcoux, n., skoglund, p. & wäglind, j. (2010): a continuous record of fire covering the last 10,500 calendar years from southern sweden – the role of climate and human activities.− palaeogeography, palaeoclimatology, palaeoecology, 291/1–2, 128–141. doi: 10.1016/j.palaeo.2009.07.013 pantaleón-cano, j., pérez-obiol, r., yll, e.i. & roure, j.m. (1996): significado de pseudoschizaea en las secuencias sedimentarias de la vertiente mediterránea de la península ibérica e islas baleares.− in: ruiz-zapata, b. (ed.): estudios palinológicos, servicio de publicaci­ ones de la universidad de alcalá de henares, 101–105. pèlachs, a., pérez-obiol, r., ninyerola, m. & nadal, j. (2009): landscape dynamics of abies and fagus in the southern pyrenees during the last 2200 years as a result of anthropogenic impacts.− review of pa­ laeobotany and palynology, 156, 337–349. doi: 10.1016/j.revpal­ bo.2009.04.005 piecuch, a., ogórek, r., dyląg, m., cal, m. & przywara, k. (2020): epicoccum nigrum link as a potential biocontrol agent against selected dermatophytes.− acta mycologica, 55/1, article 5516, 1–7. doi: 10.5586/am.5516 pyne, s.j., andrew, p.l. & laven, r.d. (1996): introduction to wildland fire (2nd edition).– john wiley & sons, new york, 808 p. rattighieri, e., rinaldi, r., bowes, k.d. & mercuri, a.m. (2013): land use from seasonal archaeological sites: the archaeobotanical evi­ dence of small roman farmhouses in cinigiano, south­eastern tuscany – central italy.− annali di botanica, 3, 207–215. doi: 10.4462/ann­ botrm­10267 regnell, m. (2012): plant subsistence and environment at the mesolithic site tågerup, southern sweden: new insights on the “nut age”.− vege­ tation history and archaeobotany, 21, 1–16. doi: 10.1007/s00334-0110299-x revelles, j. & van geel, b. (2016): human impact and ecological chan­ ges in lakeshore environments. the contribution of non-pollen palyno­ morphs in lake banyoles (ne iberia).− review of palaeobotany and palynology, 232, 81–97. doi: 10.1016/j.revpalbo.2016.05.004 revelles, j., burjachs, f. & van geel, b. (2016): pollen and non pollen palynomorphs from the early neolithic settlement of la draga ( girona, spain).− review of palaeobotany and palynology, 225, 1–20. doi: 10.1016/j.revpalbo.2015.11.001 scott, l. (1992): environmental implications and origin of microscopic pse­ udoschizaea thiergart and frantz ex r. potonie emend. in sediments.− journal of biogeography, 19/4, 349–354. doi: 10.2307/2845562 servera-vives, g., mus amezquita, m., snitker, g., floren­ zano, a., torri, p., ruiz, m. & mercuri, a.m. (2023): hu­ man­impact gradients through anthropogenic pollen indicators in a me­ diterranean mosaic landscape (balearic islands).− sustainability. 15/11, 8807, doi: 10.3390/su15118807 shang, x. & li, x. (2010): holocene vegetation characteristics of the southern loess plateau in the weihe river valley in china.− review of palaeobotany and palynology, 160, 46-52. doi: 10.1016/j.revpal­ bo.2010.01.004 shumilovskikh, l.s., seeliger, m., feuser, s., novenko, e., schlütz, f., pint, a., pirson, f. & brückner, h. (2016): the harbour of elaia: a palynological archive for human environmental in­ teractions during the last 7500 years.− quaternary science reviews, 149, 167–187. doi: 10.1016/j.quascirev.2016.07.014 shumilovskikh, l.s. & van geel, b. (2020): non-pollen palynomorphs.− in: henry, a.g. (ed.): handbook for the analysis of micro particles in archaeological samples, springer nature switzerland, cham, switzerland, 65-94. doi: 10.1007/978-3-030-42622-4_4 stockmarr, j. (1971): tabletes with spores used in absolute pollen analysis.– pollen et spores, 13/4, 615–621. šošić klindžić, r., kalafatić, h., šiljeg, b. & hršak, t. (2019): circles and ceramics through the centuries: characteristics of neolithic sopot culture settlements.− prilozi instituta za arheologiju u zagrebu, 41–48, doi: 10.33254/piaz.36.2 šošić-klindžić, r., meyer, c., milo, p., tencer, t., kalafatić, h. & šiljeg, b. (2021): all round: workflow for the identification of neolithic enclosure sites of the sopot culture in eastern slavonia (cro­ atia).− archeosciences, 45/1, 123–126. doi: 10.4000/archeosciences.8980 šošić klindžić, r., šiljeg, b. & kalafatić, h. (2024): multiscale and multitemporal remote sensing for neolithic settlement detection and protection -the case of gorjani, croatia.− remote sensing, 16, 736. doi: 10.3390/rs16050736 tanţău, i., reille, m., de beaulieu, j.-l. & fărcaş, s. (2006): la­ te glacial and holocene vegetation history in the southern part of tran­ sylvania (romania): pollen analysis of two sequences from avrig.− jo­ urnal of quaternary science, 21, 49–61. doi: 10.1002/jqs.937 tinner, w., conedera, m., gobet, e., hubschmid, p., wehrli, m. & ammann, b. (2000): a palaeoecological attempt to classify fire sensitivity of trees in the southern alps.− the holocene, 10/5, 565-574. doi: 10.1191/095968300674242447 tomac, g. (2022): stočarstvo u kasnom neolitiku istočne hrvatske: arheo­ zoološka analiza faune s lokaliteta gorjani – kremenjača i gorajni – topole [animal husbandry in the late neolithic of eastern croatia: archaeozoological analysis of fauna from the sites of gorjani – kremenjača and gorjani – topole – in croatian with english summary].− arheološki radovi i rasprave, 21, 11–28. doi: 10.21857/moxpjh1e3m tonkov, s., beug, h.-j., bozilova, e., filipova-marinova, m. & jungner, h. (2011): palaeoecological studies at the kaliakra area, northeastern bulgarian black sea coast: 6000 years of natural and anthropogenic change.− vegetation history and archaeobotany, 20, 29–40. doi: 10.1007/s00334-010-0244-4 traverse, a. (2007): paleopalynology – 2nd edition.– springer, dordrecht, 813 p. doi: 10.1007/978-1-4020-5610-9 trinajstić, i. (1998): plantgeographical division of climazonal forest ve­ getation of croatia.– šumarski list, 9–10, 407–421. tweddle, j.c., edwards, k.j. & fieller, n.r.j. (2005): multivariate statistical and other approaches for the separation of cereal from wild poaceae pollen using a large holocene dataset.− vegetation history and archaeobotany, 14, 15–30. doi: 10.1007/s00334-005-0064-0 g eo lo gi a c ro at ic a 264 geologia croatica 77/3 van de schootbrugge, b., koutsodendris, a., taylor, w.a., weston, f., wellman, c.h. & strother, p.k. (2024): recogni­ tion of an extended record of euglenoid cysts: implications for the end-triassic mass extinction.– review of palaeobotany and palynology, 105043. doi: 10.1016/j.revpalbo.2023.105043 van geel, b., bohncke, s.j.p. & dee, h. (1981): a palaecological study of an upper late glacial and holocene sequence from ‘de borchert’, the netherlands.− review of palaeobotany and palynology, 31, 367–448. van geel, b., coope, g.r. & van der hammen, t. (1989): palaeoecology and stratigraphy of the lateglacial type section at usselo (the netherlands).− review of palaeobotany and palynology, 60, 25–129. van geel, b.., hallewas, d.p., & pals, j.p. (1983). a late holocene de­ posit under the westfriese zeedijk near enkhuizen (prov. of no­ ord-holland, the netherlands): palaeoecological and archaeological as­ pects.− review of palaeobotany and palynology, 38, 269–335. waller, m.p., carvalho, f., grant, m.j., bunting, m.j. & brown, k.a. (2017): disentangling the pollen signal from fen systems: modern and holocene studies from southern and eastern england.− re­ view of palaeobotany and palynology, 238, 15–33. doi: 10.1016/j. revpalbo.2016.11.007 welc, f., nitychoruk, j., marks, l., bińka, k., rogóż-matysz­ czak, a., obremska, m. & zalat, a. (2021): forest ecosystem development in european nemoreal­boreal forest (ne poland) over the last 2200 years.− climate of the past, 17, 1181–1198. doi: 10.5194/cp-171181-2021 wojewódka, m. & hruševar, d. (2020): the role of paleolimnology in limate and environment reconstruction and lake restoration in light of research on selected bioindicators.− the holistic approach to environment, 10/1, 16–28. doi: 10.33765/thate.10.1.3 zelikson, e.m. (1995): methodology of loess palynology.− geojournal, 36, 223–228. doi: 10.1007/bf00813174 zhang, w., lu, h., li, c., dodson, j. & meng, x. (2017): pollen preser­ vation and its potential influence on paleoenvironmental reconstruction in chinese loess deposits.− review of palaeobotany and palynology, 240, 1–10. doi: 10.1016/j.revpalbo.2017.01.002 web sources: bioportal (2023): zavod za zaštitu okoliša i prirode ministarstva zaštite okoliša i zelene tranzicije [institute for environmental and nature protection. ministry of environmental protection and green transition – in croatian]. available on: http://www.bioportal.hr/. accessed: 15th march 2024. nikolić, t. (2015): flora croatica database – geoportal. faculty of science. university of zagreb. available on http://hirc.botanic.hr/fcd/beta/map/ distribution. accessed: 15th march 2024. g eologia c roatica 265hruševar et al.: the role of pollen and npp research in palaeoenvironmental reconstruction of the neolithic archaeological site “gorjani-topole” ... plate 1. description of the newly observed palynomorphs. fungi: zag-4 (1), zag-5 (2), zag-6 (3), zag-7 (4), zag-8 (5), zag-9 (6), zag-10 (7), zag-11 (8), zag-12 (9), zag-13 (10), zag-14 (11), zag-15 (12), zag-16 (13), zag-17 (14), zag-18 (15), zag-19 (16); algae: zag-20 (17); unknown origin: zag-21 (18), zag-22 (19), zag-23 (20). scale bar = 10 μm (photos 1-19), scale bar = 20 μm (photo 20). g eo lo gi a c ro at ic a 266 geologia croatica 77/3 supplement 1. grain-size analysis. sample grain-size – gorjani topole sand silt clay gt -1 34-41 2 80 18 80-90 4 77 19 130-140 5 82 13 gt-3 37-47 1 82 17 67-77 1 80 19 165-175 8 78 14 gt-4 30-40 2 77 21 70-80 3 78 19 gt-6 145-150 3 79 18 175-180 2 79 19 plate 2. some selected palynomorphs. pollen and spores: riccia (1), antocerotidae (2), convolvulus arvensis (3); amoebae: assulina muscorum (4); fungi: epicoccum (5), nigrospora (6), glomus (7), hdv-351, family sordariaceae (8); algae: hdv-225 (9), hdv-989 (10), hdv-984 (11), chomotriletes (12). scale bar = 10 μm. g eologia c roatica 267hruševar et al.: the role of pollen and npp research in palaeoenvironmental reconstruction of the neolithic archaeological site “gorjani-topole” ... supplement 2. the qualitative and quantitative content (in units) of palynomorphs. depth/ taxa gt-1 (50-60 cm) gt-1 (60-70 cm) gt-1 (158-168 cm) gt-3 (47-57 cm) gt-4 (30-40 cm) gt-4 (70-80 cm) gt-6 (55-60 cm) gt-6 (105-110 cm) po ll en a rb o re a l po ll en pinus 2 1 tilia 1 quercus robur-pubescens t. 3 alnus 2 corylus 2 2 n o n -a rb o re a l po ll en senecio 2 xanthium 2 convolvulus arvensis 1 cerealia 1 lo ca l sp o re s trilete undiff. 4 antocerotidae 3 1 riccia 1 n o n -p o ll en p a ly n o m o rp h s (n pp s) amoebae assulina 1 kn o w n f u n g i glomus 4 6 epicoccum 2 1 nigrospora 3 1 hdv-38 2 hdv-200 2 3 hdv-351 7 1 uab-7 2 uab-48 2 n ew ly d es cr ib ed f u n g a l pa ly n o m o rp h s zag-4 1 zag-5 1 2 zag-6 1 2 7 zag-7 4 2 zag-8 2 1 zag-9 1 zag-10 1 zag-11 1 zag-12 1 zag-13 2 zag-14 1 zag-15 1 zag-16 1 zag-17 4 zag-18 1 zag-19 2 2 3 2 2 2 pr o ba bl y a lg a e hdv-225 1 hdv-984 3 hdv-989 2 zag-20 1 pseudoschizaea 38 35 1 3 28 2 24 2 u n kn o w n zag-21 2 zag-22 1 1 zag-23 1 exotic marker lycopodium 100 100 100 100 100 100 100 100 g eo lo gi a c ro at ic a 268 geologia croatica 77/3 supplement 3. basic categories and their concentration values. depth pollen npps charcoal pollen conc. npps conc. charcoal conc. gt-1 (50-60 cm) 2 46 4180 5,504 126,601 11.504,196 gt-1 (60-70 cm) 3 45 592 8,256 123,849 1.629,302 gt-1 (158-168 cm) 2 12 188 5,504 33,026 517,413 gt-3 (47-57 cm) 2 16 1512 5,504 44,035 4.161,326 gt-4 (30-40 cm) 14 60 675 38,530 165,132 1.857,735 gt-4 (70-80 cm) 3 12 147 8,257 33,026 404,573 gt-6 (55-60 cm) 2 37 1810 5,504 101,831 4.981,482 gt-6 (105-110 cm) 0 2 577 0 5,504 1.588,019 2019 | 72/1 | 81–92 | 5 figs. | 4 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction plenty of landslide susceptibility models have been developed by using gis technology within the past three decades. these models have been prepared for various purposes and stakeholders, always intended to serve as an assessment of where landslides are to be expected in future. landslide susceptibility models are categorized according to various criteria, and always denoted as: quantitative or qualitative, direct or indirect, heuristic, probabilistic or deterministic, for differentiated or undifferentiated types of landslide mechanism. landslide susceptibility models and maps are being prepared on global (e.g. lin et al., 2017), continental (e.g. günther et al., 2013a), national (trigila et al., 2013), (komac & ribicic, 2006), (bălteanu et al., 2010), (glade at al., 2012) and other scales, but mostly on the regional scale (e.g. komac, 2005). regional landslide mapping is largely accepted among scientists, bearing in mind that the spatial distribution of landslide conditioning parameters changes over larger areas. in this preliminary regional landslide susceptibility assessment using limited data igor peshevski1, milorad jovanovski1, biljana abolmasov2, jovan papic1, uroš đurić3, miloš marjanović2, ubydul haque4 and natasha nedelkovska5 1 university ss. cyril and methodius, faculty of civil engineering, blvd. partizanski odredi no.24, 1000 skopje, republic of macedonia; (pesevski@gf.ukim.edu.mk) 2 university of belgrade, faculty of mining and geology, đušina 7, 11000 belgrade, serbia 3 university of belgrade, faculty of civil engineering, bulevar kralja aleksandra 73/i, 11000 belgrade, serbia 4 university of north texas health science center, department of biostatistics and epidemiology, fort worth, tx 76107, united states of america 5 geohydroconsulting ltd, manapo 7, 1000 skopje, republic of macedonia doi: 10.4154/gc.2019.03 abstract in this paper a heuristic approach for preliminary regional landslide susceptibility assessment using limited amount of data is presented. it is called arbitrary polynomial method and takes into account 5 landslide conditioning parameters: lithology, slope inclination, average annual rainfall, land use and maximum expected seismic intensity. according to the method, in the first stage, a gradation is performed for each of the carefully selected conditioning parameters by assigning so called rating points to the grid cells on which the region is divided. values of the rating points vary from 0 to 3 and depend on the parameter’s character and importance for landslide development within the region of interest. a so called total landslide susceptibility rating (tlsr) model is obtained by summing the individual rating points of each parameter and dividing the region into five susceptibility zones according to jenks natural breaks classification. verification of the tlsr model is then performed by overlaying the landslide inventory map of the selected region over the prepared susceptibility map. the sensitivity of the model can be additionally tested by multiplying the conditioning parameter’s rating points by sensitivity coefficients. in this way, additional landslide susceptibility models are obtained, named weighted total landslide susceptibility rating (wtlsr) models. as a practical example of the method, two tlsr models are presented here for the polog region in republic of macedonia, for return periods of maximum expected seismic intensity for 100 and 500 years. with over 74% of mapped landslides falling in zones of high and very high susceptibility, the results are considered satisfactory for regional scale landslide modelling and are comparable with more advanced quantitative methods. additional wtlsr models were prepared, and their correlation identified the best model. the presented approach is considered to be very convenient for conducting preliminary regional landslide susceptibility assessments with the ability to fine-tune the results. due to its simplicity, it can be applied to additional landslide conditioning parameters other than the one presented in the paper, depending on the region of interest and available data sources. it is especially practical for use in developing countries, where various organizational, technical and economic constraints prevent application of more advanced data driven methods. limitations and restrictions of the approach are also discussed. context, prominent landslide researchers (soeters & van westen 1996; mihalić, 1998; hervás, 2007; fell et al., 2008; posch-trözmüller & bäk, 2013; corominas et al., 2014) have presented ideas of the minimal requirements for performing landslide inventory, susceptibility, hazard and risk zoning in relation to the scale of mapping. one of the most applied methods in regional landslide modelling is the qualitative experience (knowledge) based – heuristic approach, which is considered a rather controversial topic in landslide assessment (barredo et al., 2000; ardizzone et al., 2002; ercanoglu et al., 2008). it is based on the use of an index or parameter maps (soeters & van westen, 1996), and it is accepted as being applicable only for the preliminary levels of research (günther et al., 2013b) if not combined with more advanced approaches (marjanović, 2014). alternatively, according to dragicević et al., (2012), heuristic methods are empirical and subject to various levels of uncertainty, but article history: manuscript received february 13, 2018 revised manuscript accepted october 26, 2018 available online february 15, 2019 keywords: regional landslide susceptibility, arbitrary-polynomial method, conditioning parameters, sensitivity, polog region g eo lo gi a c ro at ic a geologia croatica 72/182 have proven to be a reliable and cost-effective method that allows detailed and comparable assessments of landslide susceptibility. there are many different possibilities to heuristically combine various conditioning factors and produce a susceptibility map at any scale, but despite this, it is rarely the case that a particular model can be applied that gives the same results for different study area. also, using a large number of conditioning factors in a particular analysis is not a guarantee for successful susceptibility modelling. factor selection will always be subjective, so the assessment of regional factors by the expert conducting the analysis is of crucial importance. statistical methods, which are generally considered as most appropriate for landslide susceptibility mapping at regional scales because they are objective, reproducible and easily updatable (naranjo et al., 1994; he & beighley, 2008; van westen et al., 2006), also have some limitations when compared to heuristic approaches. in this regard, thiery et al. (2007) reveal major limitations that concern all statistical methods. these are as follows: (1) their significant sensitivity to the quality and accuracy of the input thematic data and particularly to the landslide inventory used to train the model, (2) the absence of expert opinion which may result in a satisfactory statistical output in terms of degree of fit, but may not be realistic in terms of physical meaning, (3) the number of landslide events to incorporate in the statistical model should be appropriate to the size of the study area, resulting in increased data requirements in large study areas, and (4) the use of oversimplified factors assumed to control or trigger landslides, by only considering information that is relatively easily mapped or derivable from a digital elevation model (dem). furthermore, gis based statistical landslide susceptibility assessment is often more focused on the tool than on the input data and frequently involves an extreme simplification of landslide controlling factors (van westen et al., 2006). therefore, in cases where a limited amount of data is available, even with a simple heuristic approach such as that presented here, and for example similar ones, such as that presented by zhu et al., (2014), it is possible to obtain satisfactory results, particularly at the regional level. landslide susceptibility models sensitivity is also the frequent subject of scientific discussion. despite the large number of recent advances and developments in landslide susceptibility modelling, there is still a lack of studies focusing on specific aspects of the model sensitivity (catani et al., 2013). it is suggested by rossi et al., (2010) that optimal susceptibility predictions might be obtained through the combination of suitable basic landslide susceptibility models generated by different methods rather than by the application of a single prediction. in this context, most recent research on landslide susceptibility model sensitivity usually comprises a comparison of different models of the same study area. examples of such correlations can be found in numerous publications (see chang & kim, 2004; oh et al., 2009; magliulo et al., 2009; rozos et al., 2010; marjanović, 2010; constantin et al., 2011; akgun, 2012; devkota et al., 2013; leopold et al., 2013; kavzoglu et al., 2014; demir et al., 2015; ramesh & anbazhagan, 2015; shahabi et al., 2015; wang et al., 2016), to name a few. in some studies, for example in lee et al., (2012), relatively complex algorithms are being engaged to check the sensitivity of a landslide susceptibility model. extraction of a particular landslide conditioning parameter and repetition of the validation process is one approach to test model sensitivity (lee & talib, 2005; guzzetti et al., 2006). other approaches for testing the sensitivity of a particular landslide susceptibility model (and not by comparison with other models) or evaluating its quality, reliability and prediction skill, are presented in (guzzetti et al., 2006; frattini et al., 2010; roy & oberkampf, 2011; petschko et al., 2014; feizizadeh & blaschke, 2014). regardless of the approach used in the model preparation, it can be stated that every modelling result is highly dependent on the quality of the input data, the assumptions made to set up the model design and the selection of the appropriate performance metrics (petschko et al. 2014). furthermore, the evaluation of reliability consists of changing some of the model integral parts and obtaining numerous variations of the outcome susceptibility maps, up to 350 in guzzetti et al., (2006). catani et al., (2013) suggest that careful sensitivity analysis which takes into consideration both conventional and innovative tools should always be performed before producing final susceptibility maps at all levels and scales. when there are various constraints for some regions of interest such as: different scales of landslide conditioning parameters maps; limited amounts of geotechnical data of historical landslides; low numbers of registered landslides in databases; no access to multi temporal aircraft imagery; no resources to perform field surveys, etc., the heuristic approach is possibly the most suitable modelling option for the researchers. in this context, in order to present the possibility of producing respective preliminary landslide susceptibility models of a region by using a limited amount of datasets due to the previously mentioned constraints, a specific heuristic approach called the arbitrary-polynomial method is presented here. the approach takes into account the findings of past research (e.g. by abolmasov & stojkov 1994, abolmasov & stojkov 1995; jovanovski et al., 2013a; peshevski et al., 2013; peshevski, 2015a). the polog region in the republic of macedonia was used as a case study area. the produced models are further tested for sensitivity, with the aim of presenting that fine tuning of heuristic landslide susceptibility maps obtained from poor datasets is feasible and is a practical tool in landslide susceptibility zonation practice. 2. the arbitrary – polynomial method the approach used in this paper is named the arbitrary polynomial method, and engages five landslide conditioning parameters: lithology, slope inclination, average annual rainfall, maximum expected seismic intensity and land use. these parameters are selected as the most representative for landslide susceptibility assessment, and their selection is based on analysis of limited historical data of landslides that had a destructive effect on the infrastructure in the republic of macedonia (peshevski et al., 2013; jovanovski et al., 2013b). it can be argued that rainfall and seismicity conditions are usually considered as triggering factors for landslide occurrence and in most cases related to landslide hazard rather than susceptibility assessment. in our case, because of their importance for the analyzed region, they were considered as landslide conditioning parameters. for the same reasons, numerous landslide susceptibility studies exist where earthquakes and/or /rainfall have been considered as landslide conditioning parameters. these studies have been performed on both local and regional scales (e.g. wang et al., 2015; erener & düzgün, 2010; ilanloo, 2011; chalkias et al., 2014; he & beighley, 2008; shibiao et al. 2013; wang et al. 2015; pamela et al. 2018; shahabi & hashim, 2015, umar et al., 2014). there are also some case studies where both of these conditioning paramg eologia c roatica peshevski et al.: preliminary regional landslide susceptibility assessment using limited data. 83 eters are taken into account when assessing global landslide susceptibility (e.g. lin et al. 2017). according to the method, a heuristic gradation is performed by assigning rating points to the landslide conditioning parameters. the value of the ratings is defined by expert assessment on the basis of particular conditioning factor importance for landslide development in a given region. in order to investigate the sensitivity to changes of these ratings, analysis is further extended by adding so called sensitivity coefficients for each of the conditioning parameters. the general framework of the method is presented in fig. 1 and details are given in the following subsections. the procedure is quite different to the statistical correlation of landslides and conditioning parameters which is the most common approach in landslide susceptibility mapping practice. it is an alternative which brings expert judgment to a central role, and not translating the problem to a more simple or complex statistical exercise. 2.1. rating maps for landslide conditioning parameters 2.1.1. lithology (lt-r) analysis of reports and thematic engineering-geological maps of historic landslides in the republic of macedonia showed that bedrock and superficial geology are among the most important factors for development of landslide processes (peshevski et al., 2013). this is usually the case with such diverse lithologies as those present in the western balkans. in our case study, when preparing a rating map for lithology, all known data for the conditions and properties of the rock masses of known landslides in macedonia were considered. after analysis of all the available thematic geological, engineering geological, geotechnical maps and cross-sections, and geotechnical reports, lithological units were grouped into six engineering-geological groups with similar physical-mechanical behavior. the rating values were assigned to all lithological units, wherein higher values indicate a higher potential for landslide occurrence. 2.1.2. slope inclination (si-r) the second significant conditional parameter is slope inclination, which is an essential element for every landslide susceptibility analysis. it is closely related to all gravitational processes, and rates of material movement are largely dependent on it. however, in the sense of measuring its potential to develop landslides, rating slope inclination is not a trivial problem, especially on regional scale landslide susceptibility and for models that should encompass different types of landslide mechanisms. in general, a more reliable connection between slope inclination and sliding processes can be found for rock fall and shallow landslides, while for deep seated landslides and especially those in the presence of groundwater, it is a very unpredictable property. each susceptibility analysis needs to consider slope inclination, with gradation done in the most logical manner, and in relation to the region of interest. slope inclination as a parameter can be appropriately obtained from existing digital elevation models (dem) of the region of interest. a polynomial interpolation is a convenient way to define ratings for the slope inclination parameter in order to encompass all types of landslides. minimal rating values are assigned even at the lowest value of 3° inclination (translational and rotational landslides in pliocene sediments on relatively flat terrain), and for all terrain over 25° inclination (mostly rock falls and rockslides), the highest rating of 3 is assigned. this type of interpolation was used for the analyzed case study region. in more detailed statistical models, the slope inclination is treated separately according to the slope movement types (landslides, rockfalls, debris flows, etc). since the presented approach is intended to give a general presentation of a region’s susceptibility, the interpolation technique is considered as very practical. in cases where detailed databases on the slope movement type exist, different interpolation curves should be applied for each of the sliding mechanisms analysed. 2.1.3. rainfall (ap-r) rainfall is governed by many factors in a region, especially elevation, mountain range orientation, climate zone, etc. in this context, severe rainstorms or periods of prolonged rainfall have been reported to trigger many shallow, or deep-seated slides and debris flows worldwide, with devastating consequences. r. macedonia is no exception. in particular, the gradot, velebrdo landslides (jovanovski et al., 2013b), and more recent ones, (probistip, makedonska kamenica, delcevo and tetovo in 2015, 2016, 2017, 2018 respectively) are clear examples of such scenarios. apart from the economic loss, some of these landslides have been lifethreatening and human losses have been reported (peshevski et al., 2017). in the absence of more precise data from particular rain gauge stations or correlations of rainfall quantities and landslide movement rates, rating values for this conditional parameter can be assigned arbitrarily according to, for example, average annual rainfall records. 2.1.4. seismic intensity (ei-r) earthquakes (considered as a conditioning factor) are also one of the main precursors of landslides. landslides in veles, skopjesopishte, berovo, and pehcevo in r. macedonia have been reported to occur after an earthquake between 1900–2015 (peshevski, 2015a). the earthquake importance according to the approach presented herein is taken into consideration through available maps of the maximum expected seismic intensity of the country. the medvedev–sponheuer–karnik (msk) scale is used as a reference in the presented case study. if other types of seismic data are available for a particular region, it can be rated in a similar manner. figure 1. flow-chart of the arbitrary polynomial method. g eo lo gi a c ro at ic a geologia croatica 72/184 2.1.5. land use (lu-r) land use ratings are assigned by comparison of the available landslide inventory of the region of interest. in the particular case presented here, corine land cover of the european environmental agency, ver. 2006 was used as reference. a landslide inventory map is overlain? with the land use map to determine in which land cover units landslides mainly occur. based on this, appropriate ratings can then be applied. 2.2. calculation of total and weighted-total landslide susceptibility ratings each specific combination of conditioning parameters is connected with a different susceptibility to sliding. the sum of the individual ratings for each conditional parameter in a grid cell (for regional scale is suggested grid cell size of 100x100m) gives its total landslide susceptibility rating (tlsr). the maximum possible theoretical value of the tlsr is 10.0 and the minimum possible value is 0.3. the following relationship is adopted: tlsr100-500 = lt-r + si-r + ap-r + ei-r + lu-r (1) where: tlsr – total landslide susceptibility rating (for return period of maximum expected seismic (earthquake) intensity for 100 and/or 500 years) lt-r – value of rating for lithological type si-r – value of rating for slope inclination ap-r – value of rating for annual precipitation ei-r – value of rating for maximum expected seismic (earthquake) intensity (for return period of 100 and/or 500 years) lu-r – value of rating for land use after calculation of the tlsr value for each grid cell, the terrain is divided into 5 classes of landslide susceptibility using jenks natural breaks classification (very low, low, medium, high, very high). by overlaying the generated tlsr model map with the available inventory map of landslides of a particular region, the validation process can then be conducted. in order to investigate the sensitivity of the basic landslide susceptibility models (tlsr models) obtained, each conditional parameter rating can be additionally weighted by so called sensitivity coefficients. in this way, a weighted total landslide susceptibility rating (wtlsr) is obtained. a sensitivity coefficient of 0.3 is assigned to the conditional parameter with the highest preference, and 0.175 for the remaining four (these all sum up to 1). this is repeated four times, wherein each time a different conditional parameter receives the 0.3 coefficient. other proportions/values of the sensitivity coefficients can also be tested (e.g 0.35 vs. 0.1625, 0.4 vs. 0.15). in our case study, other sensitivity coefficients gave less realistic outcomes. it should be noted that depending on the analyzed region and conditioning parameters used, the proportions and values of the ratings and sensitivity coefficients need to be carefully selected. this selection should be done by an expert team and then checked by running several combinations of ratings and sensitivity coefficients. it can be argued that this approach translates the susceptibility analysis into a trial and error exercise, making it highly subjective. however, with careful analysis of all the available data, weightings can be reasonably well selected, which will ultimately lead to production of a satisfactory and representative preliminary landslide susceptibility map of a particular region. following this procedure, 8 additional variants of the basic tlsr models were prepared. the maximum possible value of the wtlsr that can be obtained with the proposed sensitivity coefficients is 2.125, whereas the minimum possible value of the wtlsr is 0.0525. equations for calculation of the wtlsr used to test the tlsr models sensitivity are as follows: wlt-tlsr100 = lt-r*0.3 + si-r*0.175 + ap-r*0.175 + ei-r*0.175 + lu-r*0.175 (2) wlt-tlsr500 = lt-r*0.3 + si-r*0.175 + ap-r*0.175 + ei-r*0.175 + lu-r*0.175 (3) wsi-tlsr100 = lt-r*0.175 + si-r*0.3 + ap-r*0.175 + ei-r*0.175 + lu-r*0.175 (4) wsi-tlsr500 = lt-r*0.175 + si-r*0.3 + ap-r*0.175 + ei-r*0.175 + lu-r*0.175 (5) wap-tlsr100 = lt-r*0.175 + si-r*0.175 + ap-r*0.3 + ei-r*0.175 + lu-r*0.175 (6) wap-tlsr500 = lt-r*0.175 + si-r*0.175 + ap-r*0.3 + ei-r*0.175 + lu-r*0.175 (7) wlu-tlsr100 = lt-r*0.175 + si-r*0.175 + ap-r*0.175 + ei-r*0.175 + lu-r*0.3 (8) wlu-tlsr500 = lt-r*0.175 + si-r*0.175 + ap-r*0.175 + ei-r*0.175 + lu-r*0.3 (9) the validation process of these 8 additional wtlsr models is performed in the same manner as for the tlsr models using the landslide inventory maps. in the final stage, by detailed performance analysis of all maps generated by the models, an optimal one can be chosen as being the most representative of the particular region of interest. 3. landslide susceptibility modelling for the polog region in the republic of macedonia 3.1. study area the polog region is located in the northwest part of the republic of macedonia (fig. 2). this region covers ~2420 km2 including the densely populated towns of tetovo and gostivar (parts of which were developed on rugged hilly terrain). it includes many villages on the steep mt. shar planina, and important infrastructure including railways, a highway, well developed network of regional and local roads (mostly in the mountains), ski centers, and a very important hydro energy system consisting of 130 km of water distribution channels accompanied by 167 km of service roads. in a geological context, the study area belongs to a larger regional tectonic unit called the western macedonian zone (wmz). in this unit rock masses from the palaeozoic, mesozoic, pliocene and quaternary periods are represented. igneous rock masses include granodiorites, granites, diorites, rhyolites, serpentinites, gabbros, diabases etc. the palaeozoic is represented by a thick complex of metamorphic rocks, rarely igneous rocks. the rocks from the devonian age are the commonly occurring ones in the area, and here belong to the phyllitic schists, metaconglomerates, metasandstones, quartzites, quartz-chlorite schists, carbonate schists and marbles. it is important to note that most landslides in the study area have been reported to occur at the contact of the weak schist type rocks and the soil debris which covers them. g eologia c roatica peshevski et al.: preliminary regional landslide susceptibility assessment using limited data. 85 the study area belongs to seismic zones where the maximum expected seismic intensities of 7, 8 and 9 are likely, (according to the msk scale) for return periods of 100 and 500 years. the strongest recorded earthquake in the study area in the past 100 years was registered at its southwesternmost border on 30.09.1967 near the town of debar (magnitude 6.5, intensity 9), another strong earthquake was recorded in the northern part of the study area on 12.03.1960 in the town of tetovo (magnitude 5.6, intensity 8). it is worth mentioning that many other earthquakes ranging in magnitude from 4 – 5 have occurred in the past. despite its importance, the problem of earthquake related landslides in the region has not been well investigated. the climate in the study area is warm continental with many sunny days throughout the year. the summer is warm – hot and the winter is cold and snowy, while the spring and fall are characterized by rainfall. the medium air temperature in the region is around 11 °c, while the annual range is –20 to +38 °c. in the winter months, the snow cover reaches a thickness of 50 cm, and in the higher altitudes up to a metre. in relation to rainfall, the study area is characterized by the highest average annual precipitation in the whole country. on some of the highest elevations in the area, the annual precipitation is over 1250 mm per year, while in the flat polog valley the average is 800–900 mm. almost one third of landslides in r. macedonia have occurred in this region and many of them have caused damage to existing structures. in relation to lithological setting, 38% of the landslides in macedonia have occurred in soil debris which covers schistose or granitic bedrock, 11% in limestone (mostly rockfalls), and 31% in lacustrine sediments. other units are less well represented. according to the landslide type, in the available reports, most of the landslides were defined as translational and rotational debris and earth slides and rock falls. over 60% of the occurrences have been defined as intermediate and deep, and those mostly occurred in debris material overlying hard rock masses or in fluvioglacial and proluvial sediments. the depth of some of these landslides varies in the range from 5->25–30 metres. the remaining 40% of slides are shallow and mostly occurred in sandstones, lacustrine and flysch sediments. rockfalls are usually classified as shallow slides. almost 70% of the reported landslides in macedonia have been caused by heavy rainfall (peshevski, 2013). due to rock falls and debris flows, there have even been several fatalities (peshevski et al., 2015b; haque et al., 2016; peshevski et al., 2017). 3.2. landslide inventory a landslide inventory map of the region was prepared using available geological maps (1:25.000 to 1:100.000), google earth, a digital elevation model with resolution of 5 m, gis–portal of the national agency for real estate, ortho-photo images at a scale of 1:5.000, topographic (1:25.000) and geological maps (1:1.000 – 1:5.000) of past landslides. a total of 1172 example of slope instability were identified, most of which with undifferentiated types of slide mechanism. the size of landslides varies, but it can be stated that all of them had a clearly visible outline on some of the aforementioned data sources. for some of the landslides, published newspaper data was checked and data on their precise location was then confirmed by local residents. unfortunately, the exact date of occurrence is known for only a very small number of landslides. 3.3. rating of units inside landslide conditioning parameter maps rating of units inside landslide conditioning parameter maps were developed based on the available sources, which in this case included: the basic geological map of the r. macedonia at a scale of 1:100000 (petkovski & popovski, 1982; menković et al. 1982; petkovski & ivanovski, 1979); digital elevation model of r. macedonia with an initial resolution of 5 m (agency for real estate cadastre, 2006); seismic intensity maps of the country according to the msk scale for a return period of 100 and 500 years (seismological association of sfr yugoslavia, 1978), the 1:1.000.000, map of average annual rainfall of the country (lazarevski, 1993), 1:1.000.000, land use map according to corine clc2006 at 100 m resolution (european environmental agency, 2009). the maps and their corresponding legends are presented in fig. 3. figure 2. a) location of the republic of macedonia in europe; b) location of the case study region of polog. g eo lo gi a c ro at ic a geologia croatica 72/186 3.4. basic regional landslide susceptibility maps two basic landslide susceptibility maps were produced, for the return period of maximum expected seismic intensity of 100 years (tlsr-100) and 500 years (tlsr-500). the results of the verification are presented in tables. 1 & 2, as well as fig. 4. since more than 74% of the landslides belong in areas of high and very high susceptibility, it can be considered that both tlsr models provide a relatively good reflection of the landslide susceptibility of the region. 3.5. weighted landslide susceptibility maps eight additional wtlsr maps are prepared with the application of sensitivity coefficients. the results are presented in table 3 and fig. 5. figure 3. rating of units within landslide conditioning parameters maps; a lithological type; b slope inclination; c seismic intensity, for return period 100 and; d for 500 years; e average annual rainfalls; f land use. table 1. landslide susceptibility classes for a return period of maximum expected seismic intensity of 100 years (tlsr-100). susceptibility class tlsr-100 value area (km2) area (%) landslides landslides (%) 1 – very low 0.709-3.596 420.35 17.44 16 1.37 2 – low 3.596-4.813 459.04 19.05 126 10.75 3 – medium 4.813-6.204 487.67 20.24 162 13.82 4 – high 6.204-7.630 448.26 18.60 267 22.78 5 – very high 7.630-9.577 594.29 24.66 601 51.28 total: 2409.61 100 1172 100.00 g eologia c roatica peshevski et al.: preliminary regional landslide susceptibility assessment using limited data. 87 table 2. landslide susceptibility classes for a return period of maximum expected seismic intensity of 500 years (tlsr-500). susceptibility class tlsr-500 value area (km2) area (%) landslides landslides (%) 1 – very low 1.009-3.673 407.52 16.91 17 1.45 2 – low 3.673-4.905 478.76 19.87 130 11.09 3 – medium 4.905-6.304 485.68 20.16 148 12.63 4 – high 6.304-7.735 486.45 20.19 296 25.26 5 – very high 7.735-9.500 551.20 22.88 581 49.57 total 2409.61 100 1172 100.00 figure 4. total landslide susceptibility rating map for return period of maximum expected seismic intensity for a) 100 years; b) 500 years table 3. results from verification of the weighted – total landslide susceptibility rating models (wtlsr). model susceptibility class value of w-tlsr area (km2) area (%) no. of landslides landslides in the zone (%) difference from the initial model (%) wlt-tlsr 100 1– very low 0.124 – 0.698 429.74 17.83 25 2.13 0.76 2 – low 0.698 – 0.902 463.67 19.24 123 10.49 0.26 3 – medium 0.902 – 1.258 433.37 17.99 136 11.6 6.57 4 – high 1.258 – 1.643 414.89 17.22 239 20.39 2.39 5 – very high 1.643 – 2.051 667.94 27.72 649 55.38 4.1 total 2409.61 100 1172 100.00 wlt-tlsr 500 1– very low 0.177 – 0.746 529.24 2.56 42 3.58 2.13 2 – low 0.746 – 0.957 471.05 32.45 132 11.26 0.17 3 – medium 0.957 – 1.286 333.62 20.4 112 9.56 3.07 4 – high 1.286 – 1.651 403.18 16.72 235 20.05 5.21 5 – very high 1.651 – 2.037 672.52 27.87 651 55.55 5.98 wsi-tlsr 100 1– very low 0.150 – 0.768 385.12 15.98 11 0.94 0.43 2 – low 0.768 – 1.110 404.76 16.8 65 5.55 5.2 3 – medium 1.110 – 1.408 618.88 25.68 230 19.62 5.8 4 – high 1.408 – 1.676 430.94 17.88 280 23.89 1.11 5 – very high 1.676 – 2.048 569.91 23.65 586 50.0 0.43 wsi-tlsr 500 1– very low 0.192 – 0.786 383.66 15.92 12 1.02 0.43 2 – low 0.786 – 1.126 406 16.85 70 5.97 5.12 3 – medium 1.126 – 1.415 614.57 25.5 219 18.69 6.06 4 – high 1.415 – 1.683 423.28 17.57 275 23.46 1.8 5 – very high 1.683 – 2.037 582.1 24.16 596 50.85 1.28 g eo lo gi a c ro at ic a geologia croatica 72/188 3.6. analysis of the results from tables 1, 2 & 3, it can be seen that the landslide susceptibility model with the highest percentage of landslides in very high and high susceptibility classes is the wlt-tlsr-100. according to this model, 55.06 % of the region’s territory belongs to zones with very low, low or medium landslide susceptibility, 24.22 % of landslides have been mapped in this area. alternatively, terrains with high and very high susceptibility cover 44.94 % of the territory, with 75.77 % of the total landslides mapped. a landslide susceptibility model with the lowest percent of landslides in classes with very high and high susceptibility is the wap-tlsr-100. according to this model 58.75% of the region’s model susceptibility class value of w-tlsr area (km2) area (%) no. of landslides landslides in the zone (%) difference from the initial model (%) wap-tlsr 100 1– very low 0.137 – 0.719 412.05 17.1 10 0.85 0.52 2 – low 0.719 – 1.014 472.92 19.63 141 12.03 1.28 3 – medium 1.014 – 1.287 530.51 22.02 183 15.61 1.79 4 – high 1.287 – 1.547 396.62 16.46 235 20.05 2.73 5 – very high 1.547 – 1.926 597.51 24.8 603 51.45 0.17 wap–tlsr 500 1– very low 0.189 – 0.736 405.12 16.81 11 0.94 0.51 2 – low 0.736 – 1.027 481.14 19.97 140 11.95 0.86 3 – medium 1.027 – 1.297 529.64 21.98 175 14.93 2.3 4 – high 1.297 – 1.561 407.31 16.9 257 21.93 3.33 5 – very high 1.561 – 1.912 586.4 24.34 589 50.26 0.69 wlu-tlsr 100 1– very low 0.137 – 0.672 425.08 17.64 19 1.62 0.25 2 – low 0.672 – 0.868 451.39 18.73 123 10.49 0.26 3 – medium 0.868 – 1.109 488.93 20.29 160 13.65 0.17 4 – high 1.109 – 1.364 503.36 20.89 304 25.94 3.16 5 – very high 1.364 – 1.801 540.85 22.45 566 48.29 2.99 wlu-tlsr 500 1– very low 0.189 – 0.691 424.97 17.64 19 1.62 0.17 2 – low 0.691 – 0.885 460.33 19.1 126 10.75 0.34 3 – medium 0.885 – 1.123 482.96 20.04 151 12.88 0.25 4 – high 1.123 – 1.367 477.96 19.84 286 24.4 0.86 5 – very high 1.367 – 1.787 563.39 23.38 590 50.34 0.77 figure 5. weighted total landslide susceptibility rating maps: a wlt-tlsr100; b wlt-tlsr500; c wsi-tlsr-100; d wsi-tlsr-500; e wap-tlsr-100; f wap-tlsr-500; g wlu-tlsr-100; h wlu-tlsr-500. g eologia c roatica peshevski et al.: preliminary regional landslide susceptibility assessment using limited data. 89 territory belongs to zones with very low, low and medium landslide susceptibility, with the presence of 28.49% of the total number of landslides. terrains with high and very high susceptibility cover 41.26 % of the territory, with 71.50 % of the total landslides. in a comparison with other models, the wlt-tlsr model shows the highest prediction ability for the analyzed study area, as long as the size of the susceptibility zones is not considered. however, this does not necessarily mean that one of these models should be adopted as the most suitable for the study area, which is discussed later. the sensitivity does not show a straightforward case if we consider the landslide percentage per susceptibility class as a reference, and compare the tlsr with the wtlrs models. the model with the highest performance is not necessarily the most sensitive one, and in addition, it can be more sensitive to the change of the parameter that is not weighted with the highest value (0.3). the sensitivity varies across different landslide susceptibility classes. in most cases, very low and low susceptibility classes show the least sensitivity to any conditioning factor change, except for slope inclination, because low susceptibility classes show high change (around 5.2% in both variants, wsitlsr-100 and wsi-tlsr-500). thus, low and very low susceptibility is sensitive to slope inclination parameter change and insensitive to any other alteration. medium susceptibility class is predominantly sensitive to lithological type and slope inclination change (around 5.5% in both variants, wlt/wsi-tlsr-100 and wlt/wsi-tlsr-500). high susceptibility is particularly sensitive to the change of lithological type and annual precipitation (5.2% for wlt-tlsr-500 and 3.3% wap-tlsr-500 models), as well as to a change of land use weighting, but to a lesser extent (3.16% for the wlu-tlsr-100 model). very high susceptibility is the most sensitive to change in lithological type, with rates of 4.1–5.98%. the total sensitivity (the sum of the difference across all susceptibility classes in all models) indicates that the most dramatic changes in landslide distribution are evident for lithological type (14.08% and 16.6%, for wlt-tlsr-100 and wlttlsr-500 variants, respectively), followed by slope inclination (12.97% and 14.69%, for wsi-tlsr-100 and wsi-tlsr-500 variants, respectively). the smallest changes in landslide distribution are noted for land use (6.83% for wlu-tlsr-100 and 2.39% wlu-tlsr-500). this supports earlier claims, i.e. the sensitivity is not directly related to the performance. if we take into account the sensitivity of the different wtlsr models in relation to the change in size of the zones with high and very high susceptibility (in relation to the initial basic models tlsr100/500) and compare these with the change in number of landslides, then it can be seen that different models show changes from –1.83% to 1.68% for the size and –2.64% to 1.71% for the number of landslides (tab. 4). also, table 4 shows that models wsi-tlsr100 and wsitlsr500 have the most significant change in size of the area under high and very high susceptibility, and the least change in number of landslides in these zones, both with negative trends. on the other hand, the models wap-tlsr100 and waptlsr500 show the most significant decrease in size of the area, but in this case also with a more significant decrease in the number of landslides. the high and very high classes in models lutlsr are shown to be the least sensitive to the application of the sensitivity coefficients, while the wlt-tlsr models show correlation with a positive trend of increase both in the size and number of landslides. this leads to the conclusion that the model wsi-tlsr100 is the most suitable to be applied for this particular case study region, since the size of the area under high and very high susceptibility has reduced by 41.7 km2 from the initial model, and only 2 landslides had been moved to a lower susceptibility class zone. 4. disscussion and conclusions with the results obtained, it was confirmed that the selection of landslide conditioning parameters and the way in which they are being taken in the modelling have by far the greatest impact in any particular landslide susceptibility method. in practice various conditioning parameters are in use when performing landslide susceptibility or hazard zoning: lithology, engineering-geological characteristics of the rock masses, dem derivatives, slope aspect, elevation, normalized difference vegetation index (ndvi) , and land use, landform classification, rainfall, runoff curve number (cn), seismic influence, distance from structural elements (such as faults), distance to drainage systems, distance to linear infrastructure (roads & railways), anthropogenic factors, etc. the number of conditioning parameters in the models ranges from 3 (e.g. rapolla et al., 2012) to >20 (e.g. lagomarsino et al., 2014). all of these various susceptibility models have their advantages and disadvantages in relation to the reliability of data sources, questionable correlation with landslide development (for example the use of distance to road or distance to drainage factors), subjectivity of the engineering-geological classification methods (rock mass classification), precision of measuring instruments, etc. as shown by mihalić arbanas et al., (2016), even very high resolution bare-earth dem derivatives can have limitations in some aspects. with the methodology presented herein, it is shown that even in the case of very limited and in some cases poor amounts of data from various aspects (incomplete landslide inventory, different scale landslide conditioning maps, missing very precise data on rainfall quantity, different periods of map production, etc.) it is still possible to produce representative landslide susceptibility zonation. our modelling results show more than 74% of landslides falling in zones of high and very high susceptibility classes, which is comparable with some more complex statistical studies. he & beighley, (2008) obtained 71% and kavzoglu et al., (2014) 69–77% precision by applying statistically based algorithms. table 4. change of the total size of zones with high and very high landslide susceptibility and corresponding change of number of landslides in these zones. tlsr-100 tlsr-500 wlt-tlsr 100 wlt-tlsr 500 wsi-tlsr 100 wsi-tlsr 500 wap-tlsr 100 wap-tlsr 500 wlu-tlsr 100 wlu-tlsr 500 area (km2) 1042.55 1037.65 1082.83 1075.7 1000.85 1005.38 994.13 993.71 1044.21 1041.35 change (km2) +40.28 +38.05 –41.7 –32.27 –48.42 –43.94 +1.66 +3.7 percent of change +1,68 +1,57 –1,73 –1,34 –2 –1,83 +0,08 +0,15 no. of landslides 868 877 888 886 866 871 838 846 870 876 change in no. of landslides +20 +9 –2 –6 –30 –31 +2 –1 percent of change +1,71 +0,77 –0,17 –0,52 –2,56 –2,64 +0,17 –0,09 g eo lo gi a c ro at ic a geologia croatica 72/190 based on results presented in our research, it is obvious that there is also the possibility to test the sensitivity of landslide susceptibility models in a simple, yet acceptable manner. the optimization of preliminary prepared models should always be performed, resulting in a more robust model, with an adjusted, more realistic distribution of landslide susceptibility classes. it is hereby recommended that sensitivity testing be applied as a standard post-processing procedure in any regional heuristic landslide susceptibility analysis, and especially for cases with limited amounts of data for the landslide conditioning factors’ variability and properties of the landslides. in order to improve the sensitivity testing method presented herein, and test its reliability for use in more advanced landslide susceptibility approaches, further studies are suggested: differentiation in respect to the landslide mechanism of landslides, use of other thematic maps for the conditional parameters (for example use of peak ground acceleration maps instead of seismic intensity maps, use of maximum rainfall intensity maps for 24, 48 and 72 hours instead of annual precipitation maps) using a larger scale of some of the parametric maps, etc. it should be noted once again that, even methods such as those presented in this paper can be used only as a first estimation of landslide susceptibility, and one can argue that they are based mostly on engineering judgment. they can however provide indications of the aspects that deserve attention while allowing for the undertaking of more advanced studies in the future. for example, to point out zones of some regions where more detailed datasets need to be collected in order to apply more advanced susceptibility assessment methods. these datasets will consist of a more extensive and detailed landslide inventory of the analyzed region, supported by field mapping/remapping of more significant landslides or zones with dense landslides, same scale thematic conditioning parameter maps, and updated datasets on rainfall. therefore, the presented approach is considered to be especially practical for large scale (regional) mapping in developing countries, where various obstacles from an organizational, technical and economic nature exist. it is simple and makes reasonable the use of the limited but readily available datasets in cases where greater detail is lacking, while still producing representative susceptibility zonation of a region. the possibility to vary ratings and weightings of sensitivity coefficients of the carefully selected conditioning parameters is considered to be another advantage of the approach. due to the large scale, (the same as for other available regional susceptibility zonation methods), the spatial precision should be confirmed by repeating the analysis over a period of 5 – 10 years. such analysis should be performed using an updated landslide inventory map and, if available, refreshed datasets of the temporally dependent conditioning parameters. as for any other landslide susceptibility modelling approach, the one presented in this paper also has some limitations and restrictions. these include the inability to use it for a coarser scale analysis where more exact correlation between the landslide conditioning factors and landslide occurrences needs to be supported by detailed statistical data, rainfall thresholds, and exact earthquake intensities during sliding events. another drawback is the different scale and age of production of the thematic maps used which range from the 5 m resolution dem to the 1:1.000.000 seismic intensity maps and rainfall maps. this required certain extrapolations to be undertaken, which certainly influenced the outcome of the study. the extent of this inf luence for each extrapolated parameter should be further tested in follow-up studies. the landslide mapping technique which was applied is similar to that used in most studies at this scale, and is considered to be an error prone task as suggested by galli et al. (2008). using this technique it is only possible to produce a landslide inventory with undifferentiated mechanisms of landslide movement. therefore, to improve the quality of the inventory map, and consequently the quality of the validation processes, further landslide susceptibility studies in the region should be supported by field checks. references abolmasov, b. & stojkov, k. (1994): the influence on the landslide in urban planning in belgrade city.– in: proceedings of vii iaeg congress, lisbon, vol. iii, p. 2161–2168. abolmasov, b. & stojkov, k. (1995): jedan primer izrade karte mogucnosti pojave i razvoja klizanja.– drugi simpozijum istraživanje i sanacija klizišta, donji milanovac. akgun, a. (2012): a comparison of landslide susceptibility maps produced by logistic regression, multi-criteria decision, and likelihood ratio methods: a case study at i̇zmir, turkey.– landslides, 9/1, 93–106. doi: 10.1007/s10346-011-0283-7 ardizzone, f., cardinali, m., carrara, a., guzzetti, f. & reichenbach, p. (2002): impact of mapping errors on the reliability of landslide hazard maps.– nat. hazards earth syst. sci., 2, 3–14. doi: 10.5194/nhess-2-3-2002 barredo, j.i., benavides, a., hervás, j. & van westen, c.j. (2000): comparing heuristic landslide hazard assessment techniques using gis in the tirajana basin, gran canaria island, spain.– international journal of applied earth observation and geoinformation, 2/1, 9–23. doi: 10.1016/s0303-2434(00)85022-9 bălteanu, d., chendeş, v., sima, m. & enciu, p. (2010): a country-wide spatial assessment of landslide susceptibility in romania.– geomorphology, 124, 102–112. doi: 10.1016/j.geomorph.2010.03.005 catani, f., lagomarsino, d., segoni, s., & tofani, v. (2013): landslide susceptibility estimation by random forests technique: sensitivity and scaling issues.– nat. hazards earth syst. sci., 13, 2815–2831. doi: 10.5194/nhess-13-2815 2013 chalkias, c., ferentinou, m. & polykretis, c. (2014): gis-based landslide susceptibility mapping on the peloponnese peninsula, greece.– geosciences, 4, 176–190. doi:10.3390/geosciences4030176 chang, h. & kim, n.k. (2004): the evaluation and the sensitivity analysis of gisbased landslide susceptibility models.– geosciences journal, 8/4, 415–423. doi: 10.1007/bf02910477 constantin, m., bednarik, m., jurchescu, m.c. & vlaicu, m. (2011): landslide susceptibility assessment using the bivariate statistical analysis and the index of entropy in the sibiciu basin (romania).– environmental earth sciences, 63/2, 397–406. doi: 10.1007/s12665-010-0724-y corominas, j., van westen, c., frattini, p., cascini, l., malet, j-p., fotopoulou, s., catani, f., van den eeckhaut, m., mavrouli, o., agliardi, f., pitilakis, k., winter, m.g., pastor, m., ferlisi, s., tofani, v., hervas, j. & smith, j. t. (2014): recommendations for the quantitative analysis of landslide risk.– bulletin of engineering geology and the environment, 73, 209–263. doi: 10.1007/s10064-013-0538-8 demir, g., aytekin, m. & akgun, a. (2015): landslide susceptibility mapping by frequency ratio and logistic regression methods: an example from niksar–resadiye (tokat, turkey).– arabian journal of geosciences, 8/3, 1801–1812. doi: 10.1007/s12517-014-1332-z devkota, k.c., regmi, a.d., pourghasemi, h.r., yoshida, k., pradhan, b., ryu, i.c., dhital, m.r. & althuwaynee, o.f. (2013): landslide susceptibility mapping using certainty factor, index of entropy and logistic regression models in gis and their comparison at mugling–narayanghat road section in nepal himalaya.– natural hazards, 65/1, 135–165. doi: 10.1007/s11069012-0347-6 dragicević, s., carević, i., kostadinov, s., novković, i., abolma sov, b., milojković, b. & simić, d. (2012): landslide susceptibility zonation in the kolubara river basin (western serbia) – analysis of input data.– carpathian journal of earth and environmental sciences, 7/2, 37–47. european environmental agency (2009): 2006 corine land cover, 100 m – version 12/ 2009 erener, a. & düzgün, h.s.b. (2010): improvement of statistical landslide susceptibility mapping by using spatial and global regression methods in the case of more and romsdal (norway).– landslides, 7, 55–68. doi: 10.1007/s10346-0090188-x ercanoglu, m., kasmer, o. & temiz, n. (2008): adaptation and comparison of expert opinion to analytical hierarchy process for landslide susceptibility mapping.– bulletin of engineering geology and the environment, 67/4, 565–578. doi: 10.1007/s10064-008-0170-1 g eologia c roatica peshevski et al.: preliminary regional landslide susceptibility assessment using limited data. 91 fell, r., corominas, j., bonnard, c., cascini, l., leroi, l. & savage, w.z. (2008): guidelines for landslide susceptibility, hazard and risk zoning for land use planning.– engineering geology, 102/3–4, 85–98. doi: 10.1016/j.enggeo. 2008.03.022 feizizadeh, b. & blaschke, t. (2014): an uncertainty and sensitivity analysis approach for gis-based multicriteria landslide susceptibility mapping.– international journal of geographical information science, 28/3, 610–638. doi: 10.1080/ 13658816.2013.869821 frattini, p., crosta, g. & carrara, a. (2010): techniques for evaluating the performance of landslide susceptibility models. – engineering geology, 111/1–4, 62–72. doi: 10.1016/j.enggeo.2009.12.004 galli, m., ardizzone, f., cardinali, m., guzzetti, f., reichenbach, p. (2008): comparing landslide inventory maps.– geomorphology, 94/3–4, 268– 289. doi: org/10.1016/j.geomorph.2006.09.023. glade, t., petschko, h., bell, r., bauer, c., granica, k., heiss, g., leopold, p., pomaroli, g., proske, h. & schweigl, j. (2012): landslide susceptibility maps for lower austria, methods and challenges.– in: proceedings of 12th congress interpraevent 2012, grenoble, france, 497–508. günther, a., eeckhaut, m., reichenbach, p., hervás, j., malet, j.p., foster, c. & guzzetti, f. (2013a): new developments in harmonized landslide susceptibility mapping over europe in the framework of the european soil thematic strategy.− in: margottini, c., canuti, p. & sassa, k. (eds.): landslides science and practice. vol. 1., landslide inventory and susceptibility and hazard zoning, springer, berlin, heidelberg, 1, 297–301. doi: 10.1007/978-3-642-31325-7_39 günther, a., reichenbach, r., malet, j.p., eeckhaut, m.v.d., hervás, j., dashwood, c. & guzzetti, f. (2013b): tier-based approaches for landslide susceptibility assessment in europe.– landslides, 10/5, 529–546. doi: 10.1007/s10346-012-0349-1 guzzetti, f., reichenbach, p., ardizzone, f., cardinali, m. & galli, m. (2006): estimating the quality of landslide susceptibility models.– geomorphology, 81/ 1–2, 166–184. doi: 10.1016/j.geomorph.2006.04.007 haque, u., blum, p.,da silva, p. f., andersen, p., pilz, j., r. chalov, s., malet, j.p., jemec auflič, m., andres, n., poyiadji, e., lamas, p.c., zhang, w., peshevski, i., g. pétursson, h., kurt, t., dobrev, n., garcía-davalillo, j.c., halkia, m., ferri, s., gaprindashvili, g., engström, j. & keellings, d. (2016): fatal landslides in europe.– landslides,13/6, 1545–1554. doi: 10.1007/s10346-016-0689-3 he, y.p. & beighley, r.e. (2008): gis-based regional landslide susceptibility mapping: a case study in southern california.– earth surface processes and landforms, 33, 380–393. doi: 10.1002/esp.1562 hervás, j. (2007): guidelines for mapping areas at risk of landslides in europe.– in: proceedings of the experts meeting, jrc, ispra, italy, 23–24 oct 2007. jrc report eur 23093 en, office for official publications of the european communities, luxembourg. p. 53. doi: 10.2788/63147 ilanloo, m. (2011): a comparative study of fuzzy logic approach for landslide susceptibility mapping using gis: an experience of karaj dam basin in iran.– procedia, social and behavioral sciences, 19, 668–676. doi: 10.1016/j.sbspro.2011.05. 184 jovanovski, m., abolmasov, b. & peshevski, i. (2013a): analyses of landslide hazard evaluation factors using polynomial interpolation.− in: margottini, c., canuti, p. & sassa, k. (eds.): landslide science and practice. vol.1., landslide inventory and susceptibility and hazard zoning, springer, berlin, heidelberg, 1, 561–566. doi: 10.1007/978-3-642-31325-7_73 jovanovski, m., milevski, i., papic, j., pesevski, i. & markoski, b. (2013b): landslides in the republic of macedonia triggered by extreme events in 2010.– in: loczy, d. (eds.): geomorphological impacts of extreme weather. springer geography, springer, dordrecht, 265–279. doi: 10.1007/978-94-0076301-2_17 kavzoglu, t., sahin, e.k. & colkesen, i. (2014): landslide susceptibility mapping using gis-based multi-criteria decision analysis, support vector machines, and logistic regression.– landslides, 11/3, 425–439. doi: 10.1007/s10346013-0391-7 komac, m. (2005): probabilistic model of slope mass movement susceptibility – a case study of bovec municipality, slovenia.– geologija, 48/2, 311–340. doi: 10. 5474/geologija.2005.026 komac, m. & ribicic, m. (2006): landslide susceptibility map of slovenia at scale 1: 250,000.– geologija, 49/2, 295–309. doi: 10.5474/geologija.2006.022 lagomarsino, d., segoni, s., fanti, r., catani, f. & casagli, n. (2014): regional scale landslide susceptibility mapping in emilia romagna (italy) as a tool for early warning.– in: sassa k., canuti, p. & yin, y. (eds.): landslide science for a safer geoenvironment. vol. 2., methods of landslide studies, 2, 443–449. doi: 10.1007/978-3-319-05050-8_69 lazarevski, a. (1993): climate in macedonia. skopje (in macedonian) lee, s. & talib, j.a. (2005): probabilistic landslide susceptibility and factor effect analysis.– environmental geology, 47/7, 982–990. doi: 10.1007/s00254-0051228-z lee, m.j., choi, j.w., oh, h.j., won, j.s., park, i. & lee, s. (2012): ensemblebased landslide susceptibility maps in jinbu area, korea.– environmental earth sciences, 67/ 1, 23–37. doi: 10.1007/s12665-011-1477-y lin, l., lin, q., & wang, y. (2017): landslide susceptibility mapping on a global scale using the method of logistic regression.– nat. hazards earth syst. sci., 17, 1411–1424. doi: 10.5194/nhess-17-1411-2017 leopold, p., heiss, g., petschko, h., bell, r. & glade, t. (2013): susceptibility maps for landslides using different modelling approaches.− in: margottini, c., canuti, p. & sassa, k. (eds.): landslide science and practice. vol. 1., landslide inventory and susceptibility and hazard zoning, springer, berlin, heidelberg, 1, 353–356. doi: 10.1007/978-3-642-31325-7_46 magliulo, p., di lisio, a. & russo, f. (2009): comparison of gis-based methodologies for the landslide susceptibility assessment.– geoinformatica, 13/3, 253– 265. doi: 10.1007/s10707-008-0063-2 marjanović, m. (2010): regional scale landslide susceptibility analysis using different gis-based approaches.– in: geologically active, williams, a.l., pinches, g.m., chin, c.y., mcmorran, t.j. & massey, c.i. (eds.): proceedings of 11th iaeg congress, auckland, new zealand, 435–442. marjanović, m. (2014): conventional and machine learning methods for landslide assessment in gis.– 1st edition, palacky university in omolouc, czech republic, (monograph), 205 p. menković, lj., karović, j. & košćal, m. (1982): basic geological map of socialist federal republic of yugoslavia 1:100000, sheet prizren. prepared in period 1973–1979 by geological survey – skopje. printed by the military geographical institute of yugoslavia. mihalić, s. (1998): recommendations for landslide hazard and risk mapping in croatia.– geologia croatica, 51/2, 195–204. mihalić arbanas, s., krkač, m. & bernat, s. (2016): application of innovative technologies in landslide research in the area of the city of zagreb (croatia, europe).– geologia croatica, 69/2, 231–243. doi:10.4154/gc.2016.18 naranjo, j.l., wsten, c.j. an & seters, r. (1994): evaluating the use of training areas in bivariate statistical landslide hazard analysis – a case study in colombia.– itc journal (3): 292–300. oh, h.j., lee, s., chotikasathien, w., kim, c.h. & kwon, j.h. (2009): predictive landslide susceptibility mapping using spatial information in the pechabun area of thailand.– environmental geology, 57/3, 641–651. doi: 10.1007/ s00254-008-1342-9 pamela, p., sadisun, i. & arifianti, y. (2018): weights of evidence method for landslide susceptibility mapping in takengon, central aceh, indonesia.– iop confe-rence series: earth and environmental science, p. 118. doi: 10.1088/17551315/118/1/012037 peshevski, i., jovanovski, m., markoski, b., petruseva, s. & susinov, b. (2013): landslide inventory map of the republic of macedonia, statistics and description of main historical landslide events.− in: mihalić arbanas, s. & arbanas, ž. (eds.): proceedings of the 1st regional symposium on landslides in the adriatic-balkan region, landslide and flood hazard assessment, zagreb, croatia, 207–212. peshevski, i. (2015a). landslide susceptibility modelling using gis technology, doctoral thesis.− faculty of civil engineering, skopje, 181 p. peshevski, i., jovanovski, m., papic, br. j. & jovicic, l. (2015b): preparation of landslide susceptibility maps using gis, recent case study in r. macedonia.– scientific journal of civil engineering, 4/1, 47–53. peshevski, i., peternel, t. & jovanovski, m. (2017): urgent need for application of integrated landslide risk management stretegies for the polog region in r. of macedonia.– in: mikoš, m., vilímek, v., yin, y. & sassa, k. (eds.): advancing culture of living with landslides. vol. 5., landslides in different environments, springer international publishing, 5, 135–145. doi: 10.1007/978-3319-53483-1_43 petkovski, p. & ivanovski, t. (1979): basic geological map of socialist federal republic of yugoslavia 1:100000, sheet kicevo. prepared in period 1963-1972 by geological survey – skopje. printed by the military geographical institute of yugoslavia. petkovski, p. & popovski, s. (1982): basic geological map of socialist federal republic of yugoslavia 1: 100000, sheet gostivar. prepared in period 1967–1976 by geological survey – skopje. printed by the military geographical institute of yugoslavia. petschko, h., brenning, a., bell, r., goetz, j. & glade, t. (2014): assessing the quality of landslide susceptibility maps – case study lower austria.– natural hazards and earth system sciences, 14, 95–118. doi: 10.5194/nhess-14 95-2014 posch-trözmüller, g. & bäk, r. (2013): minimal standards for susceptibility and hazard maps of landslides and rock falls.− in: margottini, c., canuti, p. & sassa, k. (eds.): landslide science and practice, vol.1. landslide inventory and susceptibility and hazard zoning, springer, berlin, heidelberg, 1, 387–393. doi: 10.1007/978-3-642-31325-7_51 g eo lo gi a c ro at ic a geologia croatica 72/192 ramesh, v. & anbazhagan, s. (2015): landslide susceptibility mapping along kolli hills ghat road section (india) using frequency ratio, relative effect and fuzzy logic models.– environmental earth sciences, 73/12, 8009–8021. doi: 10.1007/ s12665-014-3954-6 rapolla, a., di nocera, s., matano, f., paoletti, v. & tarallo, d. (2012): susceptibility regional zonation of earthquake-induced landslides in campania, southern italy.– natural hazards, 61/1, 115–126. doi: 10.1007/s11069-0119790-z rossi, m., guzzetti, f., reichenbach, p., mondini, a.c. & peruccacci, s. (2010): optimal landslide susceptibility zonation based on multiple forecasts.– geomorphology, 114/3, 129–142. doi: 10.1016/j.geomorph.2009.06.020 roy, c.j. & oberkampf, w.l. (2011): a comprehensive framework for verificationi, validation, and uncertainty quantification in scientific computing.– computer methods in applied mechanics and engineering, 200, 25–28, 2131–2144. doi: 10.1016/j.cma.2011.03.016 rozos, d., bathrellos, g.d. & skillodimou, h.d. (2010): comparison of the implementation of rock engineering system and analytic hierarchy process methods, upon landslide susceptibility mapping, using gis: a case study from the eastern achaia county of peloponnesus, greece.– environmental earth sciences, 63/1, 49–63. doi: 10.1007/s12665-010-0687-z seismological association of sfr yugoslavia (1987): seismic zoning maps of sfry 1:1,000,000) degrees by msk-64 seismic intensity scale). for return periods of 50, 100, 200, 500, 1000 and 10000 years. shahabi, h., hashim, m. & ahmad, b.b. (2015): remote sensing and gisbased landslide susceptibility mapping using frequency ratio, logistic regression, and fuzzy logic methods at the central zab basin, iran.– environmental earth sciences, 73/12, 8647–8668. doi: 10.1007/s12665-015-4028-0 shahabi, h. & hashim, m. (2015): landslide susceptibility mapping using gisbased statistical models and remote sensing data in tropical environment.– scientific reports, 5/3:15, 9899. doi: 10.1038/srep09899 shibiao, b., qiang, x., wang, j. & pinggen, z. (2013): pre-conditioning factors and susceptibility assessments of wenchuan earthquake landslide at the zhouqu segment of bailongjiang basin, china.– journal of the geological society of india, 82, 575–582. doi: 10.1007/s12594-013-0190-8 soeters, r. & van westen, c.j. (1996): slope instability recognition, analysis, and zonation.– in: turner, a.k. & schuster, r.l. (eds.): landslides, investigation and mitigation. national academy press, washington, 129–177. thiery, y., malet, j.p., sterlacchini, s., puissant, a. & maquaire, o. (2007): landslide susceptibility assessment by bivariate methods at large scales: application to a complex mountainous environment. – geomorphology, 92/1,2, 38–59. doi: /10.1016/j.geomorph.2007.02.020 trigila, a., frattini, p., casagli, n., catani, f., crosta, g., esposito, c., iadanza, c., lagomarsino, d., mugnozza, g., segoni, s., spizzichino, d., tofani, v. & lari, s. (2013): landslide susceptibility mapping at national scale: the italian case study.− in: margottini, c., canuti, p. & sassa, k. (eds.): landslide science and practice, vol. 1., landslide inventory and susceptibility and hazard zoning, springer, berlin, heidelberg, 1, 287–295. doi: 10.1007/978-3-642-31325-7_38 umar, z., pradhan, b., ahmad, a., jebur, m.n. & tehrany, m.s. (2014): earthquake induced landslide susceptibility mapping using an integrated ensemble frequency ratio and logistic regression models in west sumatera province, indonesia.– catena, 118, 124-135. doi.org/10.1016/j.catena.2014.02.005 wang, q., li, w., chen, w. & bai, h. (2015): gis-based assessment of landslide susceptibility using certainty factor and index of entropy models for the qianyang county of baoji city, china.– journal of earth system science, 124/7, 1399–1415. doi: 10.1007/s12040-015-0624-3. wang, l.j., guo, m., sawada, k., lin, j. & zhang, j. (2016): a comparative study of landslide susceptibility maps using logistic regression, frequency ratio, decision tree, weights of evidence and artificial neural network.– geosciences journal, 20/1, 117–136. doi: 10.1007/s12303-015-0026-1 wang, q., wang, d., huang, y., wang, z., zhang, l., guo, q., chen, w., chen, w. & sang, m. (2015): landslide susceptibility mapping based on selected optimal combination of landslide predisposing factors in a large catchment.– sustainability, 7/12, 16653–16669. doi: 10.3390/su71215839 van westen, c.j., & van asch, t.w.j. & soeters, r. (2006): landslide hazard and risk zonation-why is it so difficult?– bulletin of engineering geology and environment, 65/2, 167–184. doi: 10.1007/s10064-005-0023-0 zhu, a-x., wang, r., qiao j., qin, c-z., chen, y., liu, j., du, f., lin, y. & zhu, t. (2014): an expert knowledge-based approach to landslide susceptibility mapping using gis and fuzzy logic.– geomorphology, 214, 128–138. doi: 10. 1016/j.geomorph.2014.02.003 2019 | 72/3 | 173–177 | 2 figs. | 2 pls. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the first author obtained a tuff sample containing remains of cor­ daites leaves from j. votočková-frojdová and m. libertín. one side was attached to a thin layer of coal from the uppermost part of coal seam 7. this coal sample was macerated with the aim of obtaining dispersed cuticles. although the resulting dispersed cuticle assemblage was not very rich, many conducting tissue remains were obtained, the results of which are summarised here. 2. geological setting the studied locality is at n 39°28′53”, e 106°38′08” in the wuda coal district near the city of wuda in the inner mongolia (nei mongol) autonomous region of northern china (fig. 1). the wuda district lies in the northwestern foothills of the helan shan mountain chain with elevations of over 3,000 m. the locality has an elevation of around 1,270 m (pfefferkorn & wang, 2007) and the rocks are well exposed due to the dry climate and the lack of any continuous soil or plant cover. the studied coal sample came from the uppermost part of coal seam 7, which belongs to the taiyuan formation and is separated from the overlying coal seam 6 of the shanxi formation by a tuff layer (fig. 2). both coal seams are of early permian age. dispersed plant mesofossils from the permian of wuda, inner mongolia, taiyuan formation, china zbyněk šimůnek1 and jan bureš2 1 czech geological survey, klárov 131/3, 11821 praha 1, czech republic; (zbynek.simunek@geology.cz) 2 west bohemian muzeum plzeň, kopeckého sady 2, 30100 plzeň, czech republic; (rallus@seznam.cz) doi: 10.4154/gc.2019.17 abstract a coal sample from the lower permian taiyuan formation (wuda locality, inner mongolia, china) was macerated. it yielded two cuticle fragments and many fragments of conducting tissue. one cuticle fragment shows strongly corroded polygonal cells belonging either to a pteridosperm or a cycad. the second fragment is an abaxial cordaitalean cuticle with papillate tetragonal cells and can be compared to cordaites neimengensis liu et al. 1998. the conducting tissue are represented by biseriate to quadriseriate tracheid pitting that is typical for cordaitaleans. article history: manuscript received january 31, 2019 revised manuscript accepted september 23, 2019 available online october 31, 2019 keywords: dispersed cuticles, permian, wuda, china, conducting tissue figure 2. stratigraphic section in the wuda coal mine. modified from wang et al. (2007). figure 1. location of the wuda locality in china. g eo lo gi a c ro at ic a geologia croatica 72/3174 both the taiyuan and the shanxi formations consist of coarse to fine clastic beds and coals that were deposited in fluvial, lacustrine and paludal environments (pfefferkorn & wang, 2007). the basal part of the taiyuan formation is carboniferous (stephanian, gzhelian) in age. the youngest strata in the section belong to the coal-barren lower shihezi formation (fig. 2). geotectonically the area is part of the northwestern margin of the north china plate. palaeobiogeographically, the flora belongs to the north china phytogeographic area (shen, 1995; wang & shen, 1996; shen et al., 1996; wang et al., 1999). the early permian plants of this area are generally quite similar to those of central north china (halle, 1927; lee, 1963; he et al., 1995). 3. material and methods the sample investigated was a coal attached to a tuff sample containing cordaites remains from the top of the coal seam 7 in the wuda coal opencast mine and belonged to the lower permian, taiyuan formation. the sample was collected by votočkováfrojdová and libertín during excavations with chinese colleagues in the quadrant 8d in 2016. to obtain the mesofossils, the authors used the same method as in šimůnek & bureš (2015): a 5 g sample of coal was macerated in 35 ml of concentrated (65%) nitric acid (hno3) for 2 days and 22 hours. the black residue was fully washed under running water in a sieve and then treated with 10% potassium hydroxide (koh) for up to one hour. during this process, the coal matter was mostly dissolved and cuticles, vascular tissue and fusain or black clots remained. the cuticles and conducting tissues must have been separated from the remaining matter. only two cuticles and many remains of conducting tissues were discovered and mounted in glycerine jelly slides (no. 697/1–2). some vascular tissue was mounted on stub 129 for observation under a scanning electron microscope. 4. descriptions 4.1. cuticle with polygonal cells (pl. 1, figs. a, b). a fragment of cuticle shows irregular polygonal cells, 60–130 μm long and 30–70 μm wide. anticlinal walls are straight, the periclinal wall surface is covered by small circular depressions caused by weathering or corrosion (pl. 1, fig. b). remarks: cuticles with polygonal cells are common and are often seen on the adaxial side of pteridosperm and cycad fronds. seed integuments of these plant groups have similar cuticular patterns (cleal et al., 2010). perhaps strong corrosion could explain the fact that only two cuticles were preserved in the present sample. the less cutinised cuticles were probably destroyed during fossilisation and/or subsequently during the maceration. 4.2. cordaitalean cuticle (pl. 1, figs. c, d) the cuticle has a typical cordaitalean cell pattern: parallel oriented tetragonal cells with papillae. the cells are 35–100 μm long and 9–17 μm wide. the papillae occur in a row in numbers of 4–8 on the cell surface. remarks: cuticles with this pattern of cells have so far not been observed in any group other than the cordaitales. in particular, elongated cells with papillae are typical for cordaitaleans growing in peat-forming conditions (šimůnek & florjan, 2013a,b; šimůnek & haldovský, 2015). as there are no preserved stomata, the cuticle is difficult to accommodate into the system of dispersed cuticles within the cordaitales. the genus cordaites unger is based on leaf shape and venation; and lately also on epidermal characteristics obtained from “in situ” leaf fragments (šimůnek & haldovský, 2015 and šimůnek, 2019). dispersed cordaitalean cuticles tend to be difficult to correlate with “in situ” cuticles, so an “artificial” taxonomy of cordaitalean cuticles was developed (šimůnek & florjan, 2013b). in this scheme, two fossil-genera were erected: corda­ adaxicutis šimůnek & florjan, 2013b and cordaabaxi­ cutis šimůnek & florjan, 2013b. the presence of stomata is necessary for classification into either of these genera, but they were not observed in this case. nevertheless, it is evident that this fragment belongs to the cordaitaleans. a very similar cuticle has been described by liu et al. (1998) from the lower permian of the zhungeerqi locality in inner mongolia in china and named cordaites neimengensis liu et al. 1998. a comparison of the stomata is not possible, but the cell dimensions are comparable: 62.4–144 μm in length and 9.7–16.8 μm in width. stomatal rows are separated by 1–10 rows of cells. on the fragment described here, there are 22 cell rows without any stomatal row. another very similar cuticle comes from the lower permian of the döhlen basin in germany (barthel, 1962), described as cordaites sp. typ 2 barthel, 1962. the common features are tetragonal cells with papillae. barthel (1962) presents cell dimensions as 50–100 μm long and 6–15 μm wide. the stomatal rows are separated by up to 15 cell rows. papillae are relatively common on cordaitalean cuticles isolated from coal samples, especially on abaxial cuticles (wartman, 1969; šimůnek & florjan, 2013a, b; šimůnek & haldovský; 2015, šimůnek, 2019). the cuticles in these papers have similar ordinary epidermal cells, and the stomata are arranged into stomatal rows. it is strange that neither stoma nor stomatal rows have been identified in the present fragment. up to now, papillae were not observed on adaxial cuticles. also cordaites neimengensis liu et al. does not have papillae on its adaxial cuticle. therefore. at present this cuticle fragment can only be classified as a “cordaitalean cuticle”. despite the absence of stoma and stomatal rows being preserved, we consider this cuticle to represent an abaxial one. 4.3. conducting tissue (pl. 2) tracheids of secondary xylem are preserved. most fragments contain one or two layers of tracheids. (pl. 2, fig. c, det 1). the tracheids have bordered pits in radial longitudinal section. oval bordered pits are arranged tightly one to another and have preserved a closed porus (pl. 2b, e). the tracheid pitting is mostly biseriate to quadriseriate in a tracheid width of 60–100 µm (pl. 2, figs a, c). remarks: tracheids with polyseriate pitting and tight arrangements of the bordered pitting are typical for cordaitaleans (falcon-lang et al., 2005; noll et al., 2005; bureš, 2011; mencl et al., 2013). based on these studies, cordaitalean secondary xylem contains tracheids with (1)-2-3-4-(5) series of oval bordered pits, which can have a nearly hexagonal shape and compact arrangement. the studied tracheids fully correspond to this description. no other type of tracheid has been observed. 5. discussion wartmann (1969) studied cordaitalean papillae from a biological perspective. he came to the conclusion that these papillae are not “real papillae” as they are only papillous thickenings of the cutin on cells, and not specialised cells covered with cutin. wartmann’s (1969) cordaitalean cuticles also came from a g eologia c roatica šimůnek and bureš: dispersed plant mesofossils from the permian of wuda, inner mongolia, taiyuan formation, china 175 coal seam, so this feature cannot be considered as a xerophytic indicator. wartmann (1969) wrote about “physiological xerophytness” caused by a specific condition in the peat bog, e.g. a lack of nitrogen in the soil. these papillae occur in cordaitalean cuticles prepared from coals of early westphalian to early permian strata (šimůnek, 2019; šimůnek & florjan, 2013a, b; wartmann, 1969; barthel, 1962 and liu et al., 1998). all these papillae have the same nature and have been observed only on the abaxial leaf surfaces. the coal from wuda contained very few cuticles and no palynomorphs but conducting tissues. this is strange because palynomorphs are usually preserved in coal. as palynomorphs usually do not need as long a time for maceration as cuticles and conducting tissue they may have been destroyed during the maceration process, thus explaining their absence in the sample. cuticles are sometimes very common, sometimes rare and in some types of coal they are not present at all – a situation that has not been satisfactorily explained. it does not depend only on coal maturity, because it was sometimes not possible to obtain cuticles from not highly coalified coal. in such a case megaspores usually dominate (in the westphalian). wuda is another locality with rare cuticle content, but the well preserved conducting tissue shows that the maceration was done correctly. unlike this cuticle from a coal, “in situ” cordaitalean cuticles separated from tuff specimens do not have papillae and belong to another species. secondary xylem fragments found in the coal sample contain bito quadriseriate tracheids that are typical of cordaitaleans, which is in accordance with the cordaitalean cuticle observed in the coal. 6. conclusion two cuticles from wuda were studied. one shows polygonal cells, and probably represents a pteridosperm or cycad, either from an adaxial cuticle of a frond or possibly a seed integument cuticle. the other has papillate tetragonal, parallel-oriented cells, and is considered to be an abaxial cuticle of some cordaitalean plant. because stomata are absent, this cuticle cannot be assigned to the cordaitalean dispersed cuticle classification. however, it can be compared with cordaites neimengensis liu et al. and cordaites sp. typ 2 barthel, secondary xylem with bito quadriseriate tracheids confirms the presence of cordaitalean wood in the wuda locality. acknowledgement the authors thank j. votočková-frojdová (academy of science, prague) and m. libertín (national museum, prague) for the coal sample from the wuda locality. this research was undertaken within the scope of the czech geological survey internal assignment 323100. references barthel, m. (1962): zur kenntnis inkohlter blätter der gattung cordaites presl.– hall. jb. f. mitteldt. erdg., 4, 37–39. bureš, j. (2011): silicified cordaite and conifer wood in the sediments of the líně formation of the pilsen carboniferous basin.– erica 18, 179–198 (in czech). cleal, c.j., zodrow, e.l. & mastalerz, m., (2010): an association of alethopteris foliage trigonocarpus ovules and bernaultia-like pollen organs from the middle pennsylvanian of nova scotia, canada.– palaeontog. abt. b, 283, 73–97. falcon-lang, h.j. & bashforth, a.r. (2005): morphology, anatomy, and upland ecology of large cordaitalean trees from the middle pennsylvanian of newfoundland.– rev. palaeobot. palynol., 135, 223–243. halle, t.g. (1927): palaeozoic plants from central shansi.– palaeontol. sin., ser. a, 2 (1), 1, 1–316. he, x., zhu, m. & fan, b. (1995): the late palaeozoic stratigraphic classification, correlation and biota from eastern hill of taiyuan city, shanxi province [in chinese with english summary].– jilin university press, changchun. 149 p. lee, h.-h., (1963): fossil plants of the yuehmenkou series, north china [in chinese with english summary].– palaeontol. sin., 148, 1–185. liu, z.-h., geng, b.-y, wang, s.-j. & li, c.-s. (1998): on cordaites neimengen­ sis sp. nov from lower permian of zhungerqi, inner mongolia, china.– acta bot. sin., 40/4, 383–388. mencl, v., bureš, j. & sakala, j. (2013): summary of occurrence and taxonomy of silicified agathoxylon-type of wood in late paleozoic basins of the czech republic.– folia mus. rer. natur. bohem. occident. geol. et paleobiol., 47/1–2, 14–26. noll, r., rössler, r. & wilde, v. (2005): 150 jahre dadoxylon – zur anatomie fossiler koniferenund cordaitenhölzer aus dem rotliegend des euramerischen florengebietes.– veröffentlichungen des museums für naturkunde chemnitz, 28, 29–48. pfefferkorn, h.w. & wang, j. (2007): early permian coal-forming floras preserved as compressions from the wuda district (inner mongolia, china).– int. j. coal geol., 69, 90–102. shen, g., (1995): permian floras. in: li, x., et al. (eds.), fossil floras of china through the geological ages (engl. edition).– guangdong science and technology press, guangzhou, 127–223. shen, g., wang, y., wang, j., liu, h. & zhang, s., (1996): tectonic implications of permian floras in china.– palaeobotanist, 45, 324–328. šimůnek, z. & bureš, j. (2015): dispersed cuticles and conducting tissue of sphe­ nophyllum brongniart from the westphalian d of kalinovo, donets basin, ukraine.– geol. croat., 68/1, 1–9. doi: 10.4154/gc.2015.01 šimůnek, z. & florjan, s. (2013a): an artificial system of dispersed cordaitalean cuticles from the upper silesian basin (pennsylvanian, poland) and its application to dispersed cordaitalean cuticles from the intrasudetic basin (pennsylvanian, czech republic). lethaea rossica. rossijskij paleobotanicheskij zhurnal – the russian journal of palaeobotany. paleobotanicheskij vremenik, neperiodicheskie prilozhenie k zhurnalu, 1, 53–65. šimůnek, z. & florjan, s. (2013b): the pennsylvanian cordaitalean dispersed cuticles from the upper silesian basin (poland).– rev. palaeobot. palynol., 197, 26–49. šimůnek, z. & haldovský, j. (2015): contribution to the knowledge of cordaites species from the kladno-rakovník basin, middle pennsylvanian (bolsovian) czech republic.– geol. croat., 68/2, 93–111. issn 1330-030x. doi: 10.4154/ gc.2015.11 šimůnek, z. (2019): the earliest evidence of cordaitalean cuticles from coal in the pennsylvanian of europe (langsettian, upper silesian basin, czech republic).– rev. palaeobot. palynol., 261, 81–94. https://doi.org/10.1016/j.revpa lbo.2018.11.007 wang, j., liu, l. & zhang, y. (2007): pennsylvanian through the end of permian continental sequences in shanxi and an early permian autochthonous flora in tuff in inner mongolia.– guidebook for field excursion a2. xvi int. congr. on carboniferous and permian, nanjing, 24 p. wang, j. & shen, g. (1996): permian phytogeography of china.– palaeobotanist, 45, 272–277. wang, j., zhang, q. & shen, g. (1999): permian phytogeography of cathaysian flora in china in the light of cluster analysis [in chinese with english summary].– acta palaeontol. sin., 38, 530–543. wartmann, r. (1969): studie über die papillen-förmigen verdickungen auf der kutikule bei cordaites an material aus dem westphal c des saar-karbons.– argumenta palaeobot., 3, 199–207. g eo lo gi a c ro at ic a geologia croatica 72/3176 plate 1 a, b – dispersed cuticle with polygonal cells, note the strong corrosion on fig. b. slide 697/1. a – scale bar = 100 mm; b – scale bar = 50 mm. c, d – dispersed cordaitalean cuticle. d – close up of cells with papillae. slide 697/2. c – scale bar = 100 mm; d – scale bar = 25 mm. g eologia c roatica šimůnek and bureš: dispersed plant mesofossils from the permian of wuda, inner mongolia, taiyuan formation, china 177 plate 2 conducting tissue, a–e slide 697/2; f and g sem stub 129. a – tracheids in radial longitudinal section with biand triseriate wall pitting. scale bar = 80 mm. b – close up of round tracheid pitting arranged closely to one another. 1 – closed porus is preserved on both side of the bordered pit. scale bar = 20 mm. c – tracheid layer with triand quadriseriate wall pitting. 1 – border covering two tracheid layers and delimitation of individual tracheids. scale bar = 87 mm. d – surface of bordered pits. 1 delimitation of tracheid width with triseriate pitting. scale bar = 40 mm. e – close up of tracheid surface with bordered pitting. 1 – the bordered pits adhere tightly to one another. 2 – porus is in the closed condition. scale bar = 10 mm. 2022 | 75/1 | 51–66 | 14 figs. | 3 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction landslides are the most widespread geological event affecting 4.8 million people and caused more than 18.000 deaths worldwide in the period from 1998 to 2017 (cred, 2018). in the same period, landslides, along with volcanoes and other mass movements caused damage of us $ 61 billion. given that world population growth at the moment shows a linear trend (roser et al., 2013), an increase of negative effects related to landslides is to be ex­ pected and these expectations according to schuster (1996) are based on the following reasons: increased urbanization and development in landslide-prone areas, continued deforestation of landslide-prone areas, and increased regional precipitation caused by changing climatic patterns. the systematic monitoring of landslide occurrences and the damage they cause is not established in croatia on a national level. however, by inspecting the register of damages from natural disasters at the ministry of finance, it is possible to extract some data for the period from 2015 to 2019. according to the source, the total damage from landslides in that period was us $ 22 million, counting only reported landslides and their casualties in those municipalities or cities that have declared a natural di­ saster in the specified period. this data indicates that landslides in croatia clearly present a harmful threat to humans, their properties, and the environment. still, raising public awareness of landslides as geohazard events in croatia remains a challenging task. as the earth’s surface is the only human habitat, it is logical to preserve it, which can be achieved especially through preven­ tive activities, primarily through effective planning and manage­ ment (dai et al., 2002). this approach includes restriction of de­ velopment in the landslide-prone area; use of excavation, grading, preliminary analysis of a lidar-based landslide inventory in the area of samobor, croatia vlatko gulam*, iris bostjančić, nina hećej, marina filipović and radovan filjak croatian geological survey, sachsova 2, 10000 zagreb, croatia * corresponding author: vlatko.gulam@hgi-cgs.hr doi: 10.4154/gc.2022.12 abstract the paper presents an analysis of the lidar-based landslide inventory for the area near samobor, in northwestern croatia with two main objectives: i) to define the geological units (obtained from basic geological map of sfry) most susceptible to landslides, and ii) to analyse the limitations of the basic geological map and its applicability in landslide susceptibility map design. within the study area of 63.8 km2, 874 landslide polygons were manually outlined, covering an area of 2.15 km2. the landslide outline confidence level, landslide index and the relief energy map were used to analyse the landslide susceptibility of a particular geological unit. by that, units in the same state of stress, i.e., in the same relief energy group were compared. this preliminary analysis has shown that the geological units pl,q, m3 1,2, and 1m3 1 are the most susceptible to landslides and that older geological units, pc and k1,2, are also prone to landslides. still, landslides within those older units can be considered as old and inactive. as for the limitations of the basic geological map of sfry, three things emerged, namely scale, the geological unit defining approach, and the neglect of regolith. despite the limitations presented, the usability of the basic geological map of sfry in the development of small-scale landslide susceptibility maps is emphasized. however, instructions that should attribute engineering geological features to the geological units outlined in the basic geological map should be prepared in the near future. landscaping, and construction codes; use of physical measures (drainage, slopegeometry modification, and structures) to pre­ vent or control landslides; and development of warning systems. preventative directions focused on the first step aimed to de­ termine the spatial distribution of landslide-prone areas, assess the probability of landslide occurrence, and estimate the threat of elements within the area affected by landslides. this can be achieved by making several types of maps for the area of inter­ est, covering susceptibility, hazard, and risk (chacón et al., 2006; fell et al., 2008). however, in order to be able to produce such maps by accepting the general principle that “the past and the present are key to the future” (varnes & iaeg, 1984), it is necessary to create detailed landslide inventories for a particu­ lar area (guzzetti et al., 2012). from that perspective, airborne light detection and ranging (lidar) data improved the creation of landslide inventories dur­ ing the last decade, especially when considering their precision and detail. in this study, a detailed lidar-based landslide inven­ tory is prepared for the samobor area located in the northwestern part of croatia. this area is characterized by high geological di­ versity which within the study area enables as many as 18 geo­ logical units (gus) to be distinguished within basic geological map "of sfry 1:100.000, zagreb sheet (šikić et al., 1977), herein after referred to as bgm" (bgm). based on the developed landslide inventory and available geological data, an extensive spatial analysis is performed, with the main purpose of gathering knowledge of landslide occurrence within each gu. it provides the basis for accomplishing the main objectives of this paper: i) to define the gus within the study area most susceptible to landslides, and ii) to analyse the limitations of the available geological maps and their applicability in the landslide susceptibility map (lsm) design. article history: received october 01, 2021 revised manuscript accepted november 01, 2021 available online february 28, 2022 keywords: landslide inventory, lidar, basic geological map, geological units, landslide susceptibility g eo lo gi a c ro at ic a 52 geologia croatica 75/1 2. study area the boundaries of the study area are defined within the safearth project co-financed by the interreg ipa cbc programme croatia bosnia and herzegovina montenegro. one of the main goals of this project was to create lsms at different scales and in dif­ ferent areas. in order to achieve this goal, an airborne lidar survey was performed on six pilot polygons, for which detailed landslide inventories were created. the selection of pilot polygons was based on the geological analysis, attempting to cover as wide a variability of geological environments as possible. the special geological features of the samobor polygon, which is presented within this paper, set it apart from other safearth polygons exactly due to the large number of gus and the fact that a part of the polygon is composed of carbonate rocks of triassic age. the study area covers approximately 63.8 square kilometres and is located 19 kilometres southwest of the centre of zagreb. more precisely, it is situated between sveta nedelja, samobor, and rude in the north, and drežnik podokićki and rakov potok in the south (fig. 1). most of the area belongs to the sava river basin (38.38 km2), and a smaller part to the kupa river basin (25.46 km2). 2.1. geological settings landslides as exogenetic processes are the result of the interaction between several earth systems; the lithosphere, atmosphere, and hydrosphere. professionals and scientists often analyse different natural and human factors that can trigger the landslides (e.g., li et al., 2012; zezere et al., 1999; lukić et al., 2018). however, to bring the rock material into a state of motion, the rock material first must be in a state of labile equilibrium, i.e., a large percenta ge of the rock material strength must be “consumed”. this primarily depends on two factors, namely the strength of the rock material, and then the stress (i.e., potential difference) that the rock material suffers. as this paper for the first time com­ prehensively analyses the landslides within the study area, it is logical to present that area according to these two primary fac­ tors as follows: – rock material strength is described through geological characteristics; – potential difference is described through the endogenetic movements. 2.1.1. geological units the sheets of basic geological map at scale 1:100.000 that cover the area of croatia were prepared, which for the most part lasted through the second half of the 20th century. it represents the most comprehensive overview of geology in the entire croatian territory and as such represents an unavoidable basis in any type of research that requires knowledge of the geological conditions of a particular area. according to barnes & lisle (2004), there are four main groups of geological maps, and the bgm falls into the category of regional geological maps, and as such it is produced by col­ lecting field data together with the analysis of photogeological documentation. the geological settings of the study area (fig. 1) are extensively described within the bgm sheet of sfry 1:100.000 (šikić et al., 1977) and an accompanying guide (šikić et al., 1979), according to which an overview of gus pre­ sented within the samobor area is given. the study area is composed of palaeozoic, mesozoic-palaeo­ gene, neogene and quaternary deposits. the oldest formation of permian age (p2,3), is represented by brownish sandstones with interlayers of shale and siltstone with sporadic transitions to quartz conglomerate. sediments of the lower triassic (t1) appear in the form of purple and reddish mica sandstone and siltstone and in a smaller amount of ooid limestone. in the upper part, ooid limestones with marl intercalations predominate. the sediments of the middle triassic (t2) are represented by the transition from diagenetic dolomitized stromatolite, dolo­ pelmicrite and fenestral dolopelmicrite. also, sporadically, thicklayered and massive crystalline limestone and dark mudstones are observed. the massive dolomite with weakly expressed stratification of the upper triassic (t3) are characterized by frequent interca­ lation of dolopelmicrite, fenestral dolopelmicrite and characteristic thin laminated dolostromatolite. the deposits of the cretaceous period (k1,2) are quite litho­ logically heterogeneous and are represented by medium­grained greenish sandstone, with shale, radiolarite and chert alternation. within the sedimentary rocks a larger mass of basic igneous rocks like diabase, spilitized diabase and spilite (bb) are observed. the palaeocene (pc) deposits lie transgressively on older tri­ assic or cretaceous deposits and they are mostly represented by polymictic conglomerate with imbrication of marl, siltite and sand­ stone, as well as bioclastic limestone and biolithite are observed. the sediments of ottnangian age (1m2 1) are lithologically heterogeneous with conglomerate, breccia, and gravel dominate while siltstones are subordinate. the badenian(2m2 2) sediments are characterised by biocal­ carenite, conglomerate and biolithite limestone developed in the ridge and coastal facies, while silty marl and clayey limestone developed in deeper marine sedimentary environments. sarmatian deposits (1m3 1) disconformably overlie badenian deposits in the form of biocalcarenite and sandstone deposits in the marine environment with reduced salinity, as well as charac­ teristic deep­ water laminated marl and silt with sporadic inter­ calations of sand. the shallow lake deposits of the lower pannonian (m3 1,2) better known as the „croatica layers“ are characterized by stratified clayey limestones of irregular strata that may be partly inter­ bedded with marl. in the upper pannonian, marls are deposited in a deeper lacustrine environment with interlayers of sand and sandstone. concordant on the marl, are pro-delta and delta deposits of the upper pontian (pl1,2) in the form of sand, calcite-rich siltstone and subordinate marl. sediments of pliocene-pleistocene age (pl, q) were formed in the transitional, fluvial to lacustrine environment and are rep­ resented by interbeds of gravel with sand lenses, sand with gravel lenses, clayey to sandy silt and clay with sporadically strong li­ monitization. loess (l) and loess-like sediment (lb) are mostly silty clay and clayey silt, while proluvial deposits (pr) are in the form of coarse-grained, slightly rounded gravel mixed with sand and clay. gravel, sand and clay are deposits of alluvium (a), and deposits of the second sava terrace (a2). 2.1.2. endogenetic movements within the study area the ascent of internal energy originating in the earth’s core drives a complicated set of geological processes (huggett, 2017). this energy induces endogenetic forces that continuously g eologia c roatica 53gulam et al.: preliminary analysis of a lidar-based landslide inventory in the area of samobor, croatia elevate or build up parts of the earth’s surface and hence the exo­ genetic processes fail to even­out the relief variations of the sur­ face (uppal, 2006). in that way, they give rise to the fundamen­ tal relief forms and condition the manifestation of exogenetic processes (ershov et al., 1988). from the aforementioned fundamentals, it is clear that before any pioneering research of the exogenetic processes, it is neces­ sary to determine whether the studied area is in a state of uplift or subsidence. thus, if the studied area is characterized by a pro­ nounced uplift concerning the surrounding areas, the resulting figure 1. study area: location map (on the bottom left) and bgm of sfry 1:100,000, zagreb sheet, according to šikić et al. (1977). g eo lo gi a c ro at ic a 54 geologia croatica 75/1 height difference can be considered as the accumulated energy of that area. such accumulated energy will cause a whole range of exogenetic processes, e.g., erosion (initiation of erosive surface flows), gullying (a set of exogenetic processes that take place along the erosive concentrated surface water flow), landslides, and rockfalls. since the intensity of exogenetic processes depends, among other things, on the rate of uplift, it is necessary to quantify that rate. one of the first maps dealing with the neotectonic activity in croatia is the neotectonic map at a scale of 1:1,500.000 (fig. 2) produced by the federal geological institute from belgrade (ćirić, 1967). the map shows that the studied area is characterized by ne­ otectonic uplift, while a good part of the southwestern part is characterized by neotectonic subsidence. thereby, the scale of the presented map should be kept in mind. while analysing the endogenetic movements in the study area, a proposal for future research has arisen. the correlation between neotectonic activity and the intensity of exogenetic pro­ cesses would present a valuable study, the results of which could be used as one of the crucial data sets in landslide susceptibility assessment on a national level. 3. data and methods 3.1. remote sensing data sets as predicted by jaboyedoff et al. (2012), the lidar sensor has become a standard tool for landslide analysis in this modern time. in the framework of the safearth project, an airborne sur­ vey was performed by flycom technologies d.o.o. during the spring of 2018. a lidar survey, with requested point density of 20 points per m2 and an accuracy of ±10 cm in each direction for each collected point, enabled the derivation of a high-resolution dtm with a cell size of 0.5 m. a topographic survey resulted with digital orthophotos with a 10 cm resolution. the dtm was used to create several crucial derivatives (e.g., ardizzone et al., 2007; van den eeckhaut et al., 2007; jaboyedoff et al., 2012) for the production of landslide in­ ventories: – hillshade grid with a cell size of 0.5 m, derived by a sun azimuth angle of 315° and altitude angle of 45°; – slope grid with a cell size of 0.5 m; – contour lines with one m elevation equidistance. 3.2. landslide inventory creation pike (1988) emphasises that a geometric signature is a subset of the geomorphic signatures, a broader and largely undeveloped concept that includes much more than topography. by studying the works that cite the mentioned author, it is possible to interpret the “signature” that exclusively defines the morphometry of a geomorphological phenomenon (guzzetti et al., 2012), e.g., a landslide. even though technically this possible interpretation is not entirely correct, one can conclude that a distinct signature of landslide morphometry should for certain be noticed on high­ resolution elevation models and as such can be used for landslide investigations (jaboyedoff et al., 2012). to create a landslide inventory, landslide polygons in this study were outlined manually within the gis environment using visual analysis and interpretation of the topographic surface pro­ vided by high-resolution dtm derivatives. primarily, the com­ bination of two data sets was used, slope grid as a top layer with 50 % transparency and the hillshade grid as a bottom layer. in some cases where landslide boundaries were not completely clear and sharp, the use of 3d visualisation software (esri arcsceene) was necessary to obtain the best possible results (fig. 3). each polygon within the landslide inventory is accompanied by a landslide outline confidence level (locl) aimed to describe the level of visual clarity of the individual landslides. specifically, the locl of each landslide was assessed according to how clearly the boundary of the landslide can be traced and features within the landslide body can be observed (e.g., cracks, surface depressions, hummocky topography). the locl is expressed by a grade from one to ten, where the highest grades are ascribed to those landslides with the most visible features. a very similar ap­ proach has been presented by burns & madin (2009). to conduct the analyses, the locl grades were clustered here into four groups (fig. 3). 3.3. field prospection the field prospection was performed as a part of this work, pri­ marily to gain new knowledge regarding the engineering geo­ logical properties of materials present in the study area. a field prospection at 190 observation points gave a detailed overview of: – granulometric composition of quaternary deposits which are outlined on the bgm; – lithological composition and durability of the bedrock ma­ terial; – types and characteristics of regolith, primarily thickness and granulometric composition. it should be emphasized that the data from the field prospect­ ing are insufficient for extensive statistical analyses. however, the experience gained on that occasion greatly helped in the ar­ ticulation of certain, for this paper, important conclusions. figure 2. a fragment of the neotectonic map of the sfry (ćirić, 1967). g eologia c roatica 55gulam et al.: preliminary analysis of a lidar-based landslide inventory in the area of samobor, croatia 3.4. gis analysis 3.4.1. landslide index landslide index is used to express the spatial relationship between delineated landslide polygons and gus. according to bartel­ letti et al. (2017), it is calculated as the ratio between the area of landslides occurring in a given gu and the area of that particular gu. in the same way, the landslide index of the study area is cal­ culated as the ratio between the total landslide area and the entire study area. since landslide indices are expressed in percentages, it was possible to compare the landslide index of each gu with the landslide index of the study area and draw the first conclusions about the susceptibility of each gu to landslide occurrence. 3.4.2. landslide density to get a better insight into the spatial distribution of landslides over the entire investigated area, a landslide density map was created. landslide inventory is transformed to a grid format, figure 3. examples of landslides with different locl grades presented on dtm derivatives used in the process of landslide inventory development. g eo lo gi a c ro at ic a 56 geologia croatica 75/1 where the value “one” is added to each cell that contains a land­ slide, and value “zero” to each cell without a landslide. using the focal statistics arcgis tool, a landslide density is calculated for each cell within a circle neighbourhood with a radius of 150 m. a landslide density map is used to delineate the zones for detailed analysis, in order to analyse the spatial distribution of landslides within specific gus. 3.4.3. relief energy a relief energy map is derived from the high-resolution dtm (resolution 0.5 cm). using the focal statistics arcgis tool, the elevation range is calculated by subtracting the maximum and minimum elevation within the circle neighbourhood with a radius of 150 m. the relief energy map is used as a representation of the stress state within the study area.figure 4. distribution of the geological unit area within the study polygon. figure 5. landslide inventory of the study area. g eologia c roatica 57gulam et al.: preliminary analysis of a lidar-based landslide inventory in the area of samobor, croatia 4. results 4.1. statistical sample analysis statistical sample analysis is performed to see if the area of the individual gu is statistically significant within the study area. to determine the statistical significance, a simple histogram chart is analysed, comparing the area of each gu with the average area of gus, which is taken as a reference line (fig. 4). the presented histogram shows that gus a2, 1m2 1, and ββ do not present a sta­ tistically significant sample, since the histogram bars of those units are well below the reference line. accordingly, the area of the gus pr, pl12, and pc have questionable statistical significance with histogram bars a little below the reference line. this should be kept in mind when discussing those gus, hence the results reached could be misinterpreted. for the other 12 gus, it can be pointed out that the area they cover determines a statistically sig­ nificant sample, i.e., the conclusions derived from the analysis performed are based on relevant and sufficient data. 4.2. landslide inventory map a total of 874 landslides were outlined within the investigated area. the delineated landslides cover an area of approximately 2.15 square kilometres, which is 3.4 % of the total study area. the average values of the landslide area, length, and width are 2.462 m2, 70 m, and 37 m, respectively. the landslide inventory map shows that the vast majority of landslide polygons are concentrated in the central part of the study area (fig. 5). 4.3. landslide index after the visual analysis of the landslide inventory, the landslide share for the individual gus was calculated. some basic statistics related to the gus and accompanying the landslide inventory are summarised in table 1. the landslide share analysis was con­ ducted for all 18 gus. in the analysis of landslide number and landslide index dis­ tribution within gus (fig. 6), all landslides (locl grades from 1 to 10) were taken into account. considering the landslide number (fig. 6a), it is shown that the bars for the gus pl12, m3 1,2, 1m3 1, 1m2 1, pc, k1,2 and t1 rise above the reference line which should classify them as suscepti­ ble or prone to landsliding. this analysis served as a starting point in the study aimed at identifying the “problematic” gus, regard­ ing the statistical sample size (fig. 4). the problems are related to the gus pl,q and 1m2 1, as there are 293 delineated landslide polygons within the unit pl,q and only 1 within the unite 1m2 1 (table 1). from the above, it is obvious that the representation of an individual landslide as a point loses the data of its surface area, which equalizes the importance of small and large landslides, masking landslide susceptibility characteristics for a particular gu. however, gus with large areas and a high number of land­ slides may have a landslide density per km2 below the average of the whole study polygon (e.g., pl,q). the analysis that involves the surface area of the landslides within the study polygon is presented through landslide indices (fig. 6b). this analysis shows somewhat different results to the previous one, as the bar for the gu pl,q stands above the refer­ ence line, and for gu 1m2 1 it is well below the reference line. the reason for that could be large landslide polygons delineated within that gu and this assumption is confirmed in table 1, where the gu pl,q is presented as the second one in the rank list of average landslide area for all gus. table 1. basic statistics regarding geological units and delineated landslides within the research area. g eo lo gi ca l u ni t u ni t s ha re w ith in th e st ud y ar ea [% ] n um be r o f l an ds lid es to ta l l an ds lid e ar ea in th e ge ol og ic al u ni t [ km 2 ] av er ag e la nd sl id e ar ea in th e ge ol og ic al u ni t [ m 2 ] av er ag e la nd sl id e le ng th in th e ge ol og ic al u ni t [ m ] av er ag e la nd sl id e w id th in th e ge ol og ic al u ni t [ m ] a2 0.1% 0 a 5.7% 25 0.02653 1061 37 30 pr 1.3% 0 lb 2.7% 1 0.00289 2894 122 32 l 5.8% 4 0.00369 923 72 16 pl,q 35.9% 293 0.93064 3176 62 45 pl12 2.3% 35 0.07266 2076 59 33 m3 1,2 11.4% 215 0.42321 1968 82 28 1m3 1 4.9% 84 0.17129 2039 81 30 2m2 2 6.7% 25 0.05746 2298 97 32 1m2 1 0.1% 1 0.00037 366 23 21 pc 2.5% 33 0.10969 3324 91 44 k1,2 5.9% 71 0.18799 2648 71 41 bb 0.0% 0 t3 4.0% 8 0.00954 1193 64 26 t2 4.4% 20 0.02634 1317 62 27 t1 3.3% 41 0.09073 2213 58 45 p2,3 3.1% 18 0.03836 2131 59 47 figure 6. a) number of landslides per km2 within geological units and number of landslides per km2 within the study area; b) landslide index distribution for the geological units and landslide index for the study area. g eo lo gi a c ro at ic a 58 geologia croatica 75/1 other gus are in a similar relationship to the reference line as in the previous analysis. grey bars of the units pl,q, pl12, m3 1,2, 1m3 1, pc, k1,2, and t1 (fig. 6b) are above the reference line which characterises the listed gus as susceptible to landsliding. such results did not entirely match the engineering impression that was formed during the field prospection within the study polygon and during the creation of the landslide inventory. this refers to the older gus pc, k1,2, and t1, and especially to unit pc. although landslides can be observed within the mentioned gus, they share somewhat different characteristics than landslides within the units pl,q, pl12, m3 1,2, and 1m3 1. such observations encourage further landslide index analy­ sis in which landslides of certain locl were taken into the ac­ count. landslides were grouped into four groups, based on the following locl grades: 1) from one to three (fig. 7a), 2) four to five (fig. 7b), 3) six to seven (fig. 7c), and 4) eight to ten (fig. 7d). part of the locl grade can very likely be attributed to the age of a landslide (mccalpin, 1984; bell et al., 2012) since the grade depends only on the clarity of landslide feature expression, which gradually vanishes on the terrain surface as the landslide ages. in the group of younger gus (pl,q, pl12, m3 1,2, and 1m3 1), there is no obvious trend as the bars sporadically stand above or below the reference line in all the presented charts (fig. 7). still, all of these units have been represented with bars that are well above or very close below the reference line. according to the locl, grades attributed to the landslides, both, old and recent landslides are present within those units. that could imply that these young gus are as prone to landslides nowadays as they were in recent geological history. on the other hand, the bars for older gus (pc, k1,2, and t1) show some trend from the first (fig. 7a) to the last chart (fig. 7d). it can be observed that bars related to older gus are mostly above the reference line in the charts in figure 7a and 7b, and well below the reference line in figure 7c and 7d. this means that landslides within the older gus are mostly rated with lower locl grades which could led to the con­ clusion that landslides are characterized by “blurry” features and are probably older than the landslides within the younger gus. according to the accompanying lithological characteristics (a mixture of gravel, sand, silt, and clay), the alluvial unit should be classified as a unit very susceptible to landsliding. still, be­ cause these are the youngest deposits (quaternary age) the endo­ genetic movements have not had the opportunity to bring them into a state of labile equilibrium. therefore, a high landslide share within this unit (fig. 6a and 6b; fig. 7a) is unexpected and is a result of the scale of the geological map used, which is elaborated within section 5.1.1. 4.4. landslide density map the landslide density map (fig. 8), as a derivative of the landslide inventory, highlights very similar zones as the landslide inven­ tory map (fig. 5). yet the landslide density map more clearly sin­ gles out subzones of similar characteristics in terms of landslide density, around which a more detailed discussion is presented in section 5. the subzones on the landslide density map marked as poly­ gons of detailed analyses are separated in the area of two gus, namely pl,q and 2m2 2. the polygons one, two, and three are placed within gu pl,q and were outlined using a landslide den­ sity map and an energy relief map (presented within the next chapter). although located in the same gu, these polygons indi­ figure 7. landslide index distribution for the geological units and landslide index for the study area, considering: a) landslides with locl graded between one and three; b) landslides with locl graded between four and five; c) landslides with locl graded between six and seven; d) landslides with locl graded between eight and ten. g eologia c roatica 59gulam et al.: preliminary analysis of a lidar-based landslide inventory in the area of samobor, croatia cate very contrasting environments in terms of landslide density and relief energy, discussed in more detail in section 5.2.2. polygons four, five, six, seven, and eight presented on the landslide density map are taken from the bgm and represent en­ tirely gu 2m2 2. during the analyses, an interesting difference in the share of landslides was noticed within those polygons, which is also further discussed in section 5.2.2. 4.5. relief energy map in general, a relief energy map can be used to determine the zones in which rocks are found in a similar state of stress. just by visual observation (fig. 9), there is an obvious trend going from the northwest part of the study polygon (the highest values of relief energy) to the southeast part of the study polygon (the lowest values of relief energy). in addition to the presented map, the analysis of relief energy for gus was performed and the histogram chart was made (fig. 10). this simple chart in a way follows the mentioned relief energy zones as the oldest geological units are located in the northwest part of the polygon with the highest average relief energy values. this obvious spatial trend can be followed in the histogram chart shown in fig. 10, as gus presented through average relief energy can be divided into the three following groups: figure 8. landslide density map of the study area. g eo lo gi a c ro at ic a 60 geologia croatica 75/1 a) quaternary group – units: a2, a, pr, lb, and l; b) cenozoic and cretaceous group – units: pl,q, pl12, m3 1,2, 1m3 1, 2m2 2, 1m2 1, pc, k1,2, and ββ; c) triassic and permian group units: t3, t2, t1, and p2,3. 5. discussion 5.1. geological units prone to landslides numerous studies in the professional and scientific literature dis­ cuss the conditions under which landslides may occur. in fact, the complete procedures for obtaining landslide susceptibility are based on the analyses of various conditioning factors, i.e., geoenvironmental variables. still, there are no established rules on which conditioning factors to select within the study, thus those selections are mostly based on expert opinion (jebur et al., 2014). according to reichenbach et al. (2018), based on re­ view of 565 articles, geo-environmental variables are classified into 23 classes within five clusters: i) morphological (slope, as­ pect, curvature, elevation, other morphometric, geomorphologi­ cal), ii) geological (geo-lithological, distance to fault, geo-struc­ tural), iii) land cover (land use/cover, soil, distance to road, tree, other anthropic), iv) hydrological (river/catchment, distance to figure 9. relief energy map of the study area. g eologia c roatica 61gulam et al.: preliminary analysis of a lidar-based landslide inventory in the area of samobor, croatia river), and v) other variables (precipitation, earth observation, geotechnical, seismic, other, landslide related, other climatic). all of the factors mentioned above certainly affect the land­ slide processes, and some of them are relatively easy to measure and the related data are often available. therefore, their use in the process of creating the susceptibility, hazard, and risk maps is logical and above all justified. however, when assessing the sus­ ceptibility of geological or eg units, or better yet when compared to each other, it seems necessary from an engineering point of view to return to the foundations of mechanical settings. in other words, to consider two factors that are crucial for landslide oc­ currence which are the stress conditions within certain parts of the relief, and the strength (internal resistance force) of the ma­ terial within a particular gu. this means that conclusions about whether one gu is more susceptible to landslides than another can be drawn only when the analysed units are in a state of equal stress state, i.e., when their strength is consumed in equal or similar amounts. for such an estimate of landslide susceptibility characteristics for a par­ ticular gu, it is logical to use the combination of the two parameters presented in this paper, namely landslide index and relief energy. relief energy is defined as the height difference within the particular terrain surface, and as such, it can indicate a certain state of stress within the particular surface area. by accepting this approach, every energy relief group (fig. 10) could be con­ sidered as a group that suffers similar stress. such an approach may also imply that a comparison of landslide susceptibility levels of particular gus can be performed only within a single energy relief group. for estimation of the strength as a starting point, the land­ slide index can be used. however, for deeper analyses of landslide susceptibility within the one relief energy group, one should cer­ tainly consider the geological composition of the particular gu. 5.1.1. relief energy group a this group consists of quaternary deposits the genesis of which is related to water and wind erosion. namely, these young alluvial, proluvial, and loess sediments have been deposited on floodplains in a wider area and as such are certainly prone to landsliding. still, endogenetic movements have not yet had the opportunity to uplift them. consequently, this group is characterized by the lowest level of relief energy, in a range from one to fifteen m (fig. 10). the low levels of the landslide index are therefore logical and expected. it is clear that in all the graphs (fig. 6 and fig. 7) the landslide index in the gus of the relief energy group a is much lower than the average level of the landslide index for the entire study area. this observation is somewhat disturbed by a slightly larger landslide index for the gu a (alluvium fig. 6a and 6b; fig. 7a). this can be related to the scale of the geological map used, which is elaborated on in more detail in section 5.2.1. 5.1.2. relief energy group b relief energy group b has a moderate level of energy in relation to other groups formed within this paper with the range of aver­ age relief energy (fig. 10) from 25 m (gu pl,q) to 43 m (gu pc). values of the landslide indices are very scattered within relief energy group b (fig. 6 and fig. 7), and that is especially empha­ sized in fig. 7. this scattering indicates that the gus are very diverse in terms of susceptibility to landsliding, but it can also indicate different bedrock material, different regolith material, and finally different types and mechanisms of landsliding. the following brief analysis of the landslide index related to the gus of this group can serve as a starting point for future rec­ ommendations associated with the reclassification of the gus defined on the bgm into the eg units. this can be especially important for the creation of the eg maps at a small scale as a crucial input data in lsm design. without going into deeper analyses, one could conclude that within the relief energy group b according to the landslide index (fig. 6b), there are two groups of gus. namely, those with bars standing above the reference line (landslide susceptible units – pl,q, pl12, m3 1,2, 1m3 1, pc, and k1,2) and those with bars standing below (landslide unsusceptible units – 2m2 2, 1m2 1, and ββ). such conclusions would be very hasty for several reasons, which will be briefly elaborated below. statistical sample the low landslide index for the 1m2 1 and ββ units presented in the scope of this research can be attributed to an insufficient statistical sample (fig. 4). although from an engineering point of view it would be justified to classify these gus as unsuscep­ tible to landsliding according to their lithology, it would be wise to support such conclusions in future research by analysing the landslide inventory in areas where these gus are better repre­ sented. although the high landslide index is defined for gus pl12 and pc (fig. 6b), it should be repeated that the statistical sample analysis for those units confirmed a questionable statistical sig­ nificance (fig. 4). gu pl,q covers a very large part of the study area (35.9 %) and according to the landslide index (fig. 6b) could be labelled as a high landslide susceptible unit. similarly, gu 2m2 2 covers a statistically significant area (6.7 %) and according to the landslide index (fig. 6b) could be labelled as a low landslide susceptible unit. still, the lithology of these units is very diverse so the land­ slide susceptibility level should be defined with caution. the litho logical heterogeneity of the parent rock which strongly influ­ ences the landslide density within those units is discussed as a part of one of the bgm limitations in section 5.2.2. landslide outline confidence level (locl) as already described, the locl generally defines the visibility and sharpness of a landslide on dtm derivatives used in land­ slide inventory creation. by accepting the assumption that the locl grade can be assigned to the landslide age, it is possible to conclude that gus m3 1,2 and 1m3 1 are still somewhat more sus­ ceptible to landslides in recent climatic conditions than gu k1,2, figure 10. average relief energy distribution for the geological units within the study area. g eo lo gi a c ro at ic a 62 geologia croatica 75/1 due to the higher locl grades. the answer to the question why unit k1,2 is less susceptible to landslides in recent climatic condi­ tions than units m3 1,2 and 1m3 1, should be sought in the eg char­ acteristics of the near-surface parts of the above mentioned gus. gus m3 1,2, 1m3 1, and k1,2 are characterized by sliding sur­ faces located in the regolith formed above the bedrock. thus, several important features of both regolith and bedrock need to be considered to assess their susceptibility to landslides, and those are: thickness and granulometric composition of the rego­ lith; susceptibility of the bedrock to the mechanical weathering, i.e. formation of the regolith; and the permeability of the bedrock. the granulometric composition, especially the proportion of the coarse-grained fraction, strongly influences the physico-me­ chanical properties of the regolith-like materials (park et al., 2018; indrawan et al., 2006; shakoor & cook, 1990). with the increase of the coarse-grained fraction, the water per­ meability also increases, which prevents the growth of pore pres­ sure which strongly affects the slope stability. similarly, the wa­ ter permeability of the bedrock strongly contributes to the oscillation of the pore pressure at the contact with the upper rego­ lith. therefore, if the bedrock is characterised by low permeability (e.g., marl) it is very likely that the high pore pressure zone will be formed at the contact surface of the regolith and bedrock, presenting a potential sliding surface. by taking all this into account in combination with the knowledge gained during the fieldwork and by studying the literature, it is possible to distinguish two different models. for gus m3 1,2 and 1m3 1 the regolith can be defined as 1 to 5 m thick, with a very small proportion of a coarse-grained frac­ tion, and low permeability. the bedrock is susceptible to the for­ mation of a thicker regolith and is poorly water-permeable. with such characteristics, this eg model is defined as a high landslide susceptible one, due to the possible rapid disturbance of the me­ chanical stability on slopes. for gu k1,2 the regolith can be defined as 1 to 3 m thick, with a variable proportion of the coarse-grained fraction, and variable levels of water permeability. the bedrock is susceptible to the formation of a medium­thick regolith and with variable level of water permeability. with such characteristics this eg model is defined as being of low landslide susceptibility espe­ cially in the current climatic conditions. the approach presented seems to be a good direction that can be used in the reclassification of the gus defined within the bgm into the egus required for lsm development. this ap­ proach has already shown good results in landslide susceptibility mapping of the sisak-moslavina county (bostjančić et al., 2021), which certainly encourages future more serious attempts in a similar direction. figure 11. a) relief energy for the alluvial gu within the boundary outlined on the map at a scale of 1:100.000; b) relief energy for the alluvial gu within the boundary outlined on the map at a scale of 1:5,000. g eologia c roatica 63gulam et al.: preliminary analysis of a lidar-based landslide inventory in the area of samobor, croatia 5.1.3. relief energy group c this group has the highest average relief energy within the study polygon, ranging from 53 m to 64 m, which may be a conse­ quence not only of more pronounced endogenetic uplift, but also the strength of the bedrock material. landslide indices of gus within this group indicate extremely low (t2 and t3) and low (t1 and p2,3) landslide susceptibilities (fig. 6b). slightly higher land­ slide indices for gus t1 and p2,3 are very likely due to a thicker regolith superficial layer with characteristics very similar to gu k1,2. geological units t2 and t3 are characterised by a very thin and permeable regolith superficial layer (up to 1 m), and perme­ able bedrock (dolomite and limestone) which is why they can be classified as having an extremely low susceptibility to landslides. 5.2. limitations of the bgm in lsm creation one of the pre-defined goals of this paper was to test the usability of the bgm in the process of lsm creation. interesting observations elaborated later in this section try to present the well­known limitations of this map in a simple and illustrative way. however, here, based on logical and numerically measurable details, closely related to the occurrence of landslides, an attempt was made to show the level of the limitations of the geological maps that cover the whole croatian territory. 5.2.1. scale the scale of any type of map affects the level of detail that can be shown on the map and the spatial accuracy of the cartographic elements (perkins & parry, 1990), e.g., geological bounda­ ries and faults. how the scale affects the precision of the line ele­ ment (in this case the geological boundary) is shown by a simple analysis of the boundary of the alluvial deposits. during the analysis of the quaternary geological group, for an alluvial gu, a slightly higher landslide index was observed (fig. 6 and fig. 7a). besides, a somewhat higher value of the average relief energy was also noticed (fig. 10). as these quaternary sediments are deposited on floodplains, such values of landslide index and average relief energy are not logical. this inaccuracy is attributed to the scale of the bgm, which was used to deline­ ate the gus polygons. in order to confirm the stated claim, anal­ ysis of the polygon outlining part of the alluvial deposits in the study area is presented. in figure 11 two different geological boundaries are shown. the first is taken from the bgm at a scale of 1:100,000 that was used in this study (fig. 11a) and the second one is taken from the geological map at a scale of 1:5,000 which was made for the part of study area within the safearth project (fig. 11b). presented polygons were used to clip the relief energy map. the cells that were left within the polygons were analysed and compared. the polygon outlined from the small-scale map contains parts of high energy relief, while the polygon outlined from the large-scale map contains mild energy relief. the basic statistics of these differences are given in table 2. the age and the genesis of the alluvial material imply that these deposits are placed in plains where endogenetic movements have not yet uplifted the terrain. in that sense, the low average relief energy is largely to be expected. as the lower value of this parameter is obtained using the large-scale geological map, it cer­ tainly seems more accurate and thus more acceptable. accordingly, the bgm should be used with caution in the process of lsm creation, i.e., it can be used for the production of lsm at the same or similar scale, and in no circumstances at scales larger than 1:25,000. 5.2.2. geological units defining approach instructions for bgm design define the approach for outlining the gus within the different types of rocks (igneous, metamorphic and sedimentary; savezni geološki zavod, 1962). thus, for sedimentary rocks, the first criterion is age, while for igneous and metamorphic rocks it is lithological composition. the pre­ sented approach in separating sedimentary gus from the aspect of engineering geology causes quite a problem, as lithology largely conditions the engineering geological properties. with such an approach, gus with very heterogeneous lithological com­ position have been outlined, which makes the assessment of their susceptibility to landslides very difficult, and in some cases even impossible. this problem is described through the analysis of two gus outlined within the study area, pl,q and 2m2 2. pl,q this unit consists of gravelly, sandy, silty and clayey sediments, mostly deposited in the form of lenses. solid rocks are present in the form of breccias and conglomerates but their prevalence is almost negligible. only a few scientific papers analyse pl,q deposits (novosel-škorić et al., 1986; šikić, 1995; hećimović, 2009), but unfortunately, none of them seem to analyse in more detail the lithological heterogeneity of these deposits. in terms of land­ slide activation, the importance of detecting the spatial distribu­ tion of individual fine and coarse-grained lithological members within pl,q deposits is presented. this gu is characterised by landslides with a deeper failure surface and the main triggering factor is the increase in pore pres­ sure due to the existence of lenses of coarse fraction material in the fine-grained soil mass. it should certainly be emphasized that the explanation given below regarding the landslide triggering mechanism within the gu pl,q came from insufficiently detailed research, which sug­ gests that the given conclusions should be confirmed in the future by conducting research that is even more detailed. three zones within gu pl,q based on different landslide density were separated (fig. 8), in which the main criterion was a contrasting spatial distribution of landslides. since all three polygons were isolated in the gu pl,q with the primary assump­ tion that they share similar lithological characteristics (with the same resistance force, i.e., strength), the cause of the different landslides density had to be sought in the state of stress within each outlined polygon. thus, the polygons were added to the en­ ergy relief map (fig. 9) to determine their average relief energy. finally, for all three zones, the landslide share and average relief energy were overlapped and analysed (fig. 12). zone one, which has the highest landslide share, somewhat unexpectedly does not have the highest average relief energy. zone two with the lowest landslide share, unexpectedly, has the table 2. basic statistics regarding relief energy for the alluvial geological unit within the maps of different scales. statistics geological map [1:100000] geological map [1:5000] min 1 1 max 56 44 average 14.0 11.8 variance 95.2 51.1 stan. deviation 9.8 7.1 g eo lo gi a c ro at ic a 64 geologia croatica 75/1 highest average relief energy. even the data related to zone three have somewhat unexpected results because that zone has the low­ est average relief energy and a relatively high landslide share. the analysis presented led to re-examination of the first as­ sumption, which is that the entire gu pl,q is characterized by a similar lithology. during preliminary field profiling in all three zones, the field determination of soil samples was conducted. it suggested that zones one and three are characterized by a very heterogeneous lithological environment, i.e., an environment of very diverse granulometric composition in which the fine-grained fraction is somewhat predominant. zone 2 is more likely charac­ terized by coarse-grained material (sand and gravel). this conclusion made it possible to design the two charac­ teristic eg models for the gu pl,q (fig. 13). model a (fig. 13a) is related to zones one and three (fig. 12), and model b (fig. 13b) to zone two (fig. 12). model a describes landslide activation caused by increased pore pressure in the fine-grained material and erosion of the landslide toe. in model b, landslide activation in the current state of stress is not possible because the present lithology drains very easily, i.e., an increase in pore pressure is not possible. landslide foot erosion is also not possible because surface erosive flows cannot develop due to the very rapid infil­ tration of surface water into deeper horizons the gu pl,q has been indicated in many previous works as a unit susceptible to landslides (jurak et al., 1998; mihalić et al., 2008). the graphs in fig. 7 certainly confirm these claims, however, when designing future lsms (especially at a smaller scale for which new lidar substrates will not be made), this unit should be considered as highly heterogeneous. the recommen­ dations (guidelines) that should follow such maps must indicate such properties of these deposits, which would certainly require very detailed research necessary for the production of lsms at a larger scale. 2m2 2 the badenian geological complex stands out with a lower land­ slide index compared to other gus within the relief energy group b (fig. 6 and fig. 7). although the bgm (šikić et al., 1977) con­ sider this complex as a single gu, from the lithological point of view (vrsaljko et al., 2006; vrsaljko et al., 2007) these figure 13. characteristic models for gu pl,q; model a very heterogeneous lithology from fine-grained to coarse-grained fraction; model b homogeneous coarse-grained (sand and gravel with very little coarse-grained silt) lithology. figure 12. average relief energy and landslide share for the three zones within the gu pl,q outlined on the landslide density map. g eologia c roatica 65gulam et al.: preliminary analysis of a lidar-based landslide inventory in the area of samobor, croatia are very diverse deposits, which can be divided into at least two eg units: 1) eg unit 1 biocalcarenite, conglomerate, and biolithite limestone; 2) eg unit 2 silty marl and clayey limestone. these lithological units differ in water permeability and level of weathering durability. as such, they create regolith complexes of different thicknesses and granulometric features with very di­ verse water-permeable values (table 3). from all the above, it is obvious that the units described in this way also differ in their landslide susceptibility level, which was attempted to visualize through the following very simple analysis. the polygons of badenian deposits (2m2 2) from the bgm (fig. 1) have been grouped according to the visual criterion of landslide density (fig. 8). the polygons are labelled on the map from four to eight. for each polygon, the corresponding landslide index was calculated and the obtained results are presented in figure. 14. as expected, the outlined polygons have very different land­ slide indices, which very likely confirms the thesis of diverse li­ thology. the assumption, which has been verified to some extent by fieldwork, suggests that polygons five, six, and eight are part of eg unit 1 due to their very low landslide index. eg units 1 and 2 equally build polygon seven, due to the landslide index close to the landslide index of the entire study area. polygon four is probably related to eg unit 2 due to the high landslide index. the pres­ ence of limestone within polygon four can also be confirmed by the large number of sinkholes which are characteristic of this li­ thology. 5.2.3. neglecting the regolith regolith is a general term for the layer of unconsolidated or uncemented, weathered material which overlies bedrock over much of the land surface. it includes rock fragments, mineral grains, and all other superficial deposits such as unlithified in situ sap­ rolite, ash, colluvium, alluvium or drift (kearey, 2001; allaby & allaby, 2003). superficial deposits that can be characterized as regolith, according to the presented definition, are mostly of quaternary age, and as such, following the bgm instructions are ignored in most cases (e.g., they are not outlined if their thickness is less than 5 m; savezni geološki za­ vod, 1962). during the fieldwork in the study area, it has been confirmed for older gus (m3 1,2; 1m3 1; 2m2 2; 1m2 1; pc; k1,2, ββ, t3, t2, t1, and p2,3) that landslides occur almost exclusively in the regolith layer. thereby, it can be concluded that for research re­ lated to landslides, this is the most important limitation of the bgm. 6. conclusion here, a lidar-based landslide inventory is presented and ana­ lysed for the first time, for 63.8 km2 of the samobor area, (located in the northwestern part of croatia). using high-resolution dtm lidar derivatives, 874 landslide polygons were outlined, cover­ ing an area of 2.15 km2 (3.4 %). according to the bgm at a scale of 1:100.000, the study area is characterised by strong geological diversity, where 18 gus were distinguished. this enabled extensive spatial analysis to correlate the gus and landslide occurrence and to define the units most susceptible to landslides. thereby, two factors crucial for landslide occurrence were considered. namely, the stress state expressed as relief energy, and the strength of the material described by the landslide index. the analysis is based on the approach that the same average relief energy implies the same average stress state. for this reason, landslide indices were compared for gus within the same relief energy group. the results of statistical sample analysis were also taken into account, which clearly showed the representation of each unit in the observed area. as a final result, gus pl,q (gravel, sand, clay, and silt), m3 1,2 (clayey limestone and -marl), and 1m3 1 (biocalcarenite, sand­ stone, marl, silt with intercalation of sand) stood out as being the most susceptible to landslides. the analysis has also shown that older gus, pc (conglomerate, marl, siltite, and sandstone) and k1,2 (sandstone, shale, radiolarite and chert), are prone to landslides. still, according to lower locl grades, which are given to each landslide based on the visibility and sharpness of landslide fea­ tures, the landslides within those units can be considered as old and inactive. analysis of landslide inventory together with the field prospection revealed some significant limitations of the bgm when considering their usage in lsm design. in the paper, spe­ cial attention was given to the limitations related to the scale, geological unit defining approach, and neglecting the regolith. however, the analysis also confirmed that the bgm has an im­ portant application in small­scale landslide susceptibility map­ ping, especially as a valuable set of maps that cover the whole territory of croatia based on equal methodology. it is very diffi­ cult to expect that in the near future a superficial map for croatia will be developed. therefore, to try to reduce the negative im­ pacts of the bgm limitations, it seems logical to propose the in­ structions to attribute eg features to gus outlined on the bgm. using such instructions in the process of small-scale lsm deri­ vation will increase the accuracy of assessed landslide suscepti­ bility, which will encourage the use of lsms, especially in the spatial planning sector. table 3. basic engineering geological features of the badenian lithofacies formation gained from preliminary fieldwork. eg unit bedrock regolith eg unit 1 highly permeable with low potential for regolith formation up to 1 m thick, large proportion of coarse-grained fraction, highly water-permeable eg unit 2 very poorly permeable with very high regolith formation potential up to 5 m thick, very low coarse-grained fraction, low water permeability figure 14. landslide indices for the badenian polygons (2m2 2) shown within fig. 8. g eo lo gi a c ro at ic a 66 geologia croatica 75/1 acknowledgment lidar-based digital terrain model used within this study was obtained in the framework of the safearth project, co-financed by the interreg ipa cross-border cooperation programme croa­ tia bosnia and herzegovina montenegro 2014-2020. references allaby, a. & allaby, m. (2003): a dictionary of earth sciences.– oxford univer­ sity press, oxford, 619 p. ardizzone, f., cardinali, m., galli, m., guzzetti, f. & reichenbach, p. (2007): identification and mapping of recent rainfall-induced landslides using elevation data collected by airbone lidar.– natural hazards and earth system sci­ ences, 7, 637–650. doi: 10.5194/nhess-7-637-2007 barnes, j.w. & lisle, r.j. (2004): basic geological mapping.– john wiley & sons ltd, chichester, 184 p. bartelletti, c., giannecchini, r., d’amato avanzi, g., galanti, y. & mazzali, a. (2017): the influence of geological–morphological and land use settings on shallow landslides in the pogliaschina t. basin (northern apennines, italy).– journal of maps, 13/2, 142–152. doi: 10.1080/17445647.2017.1279082 bell, r., petschko, h., röhrs, m. & dix, a. (2012): assessment of landslide age, landslide persistence and human impact using airborne laser scanning digital terrain models.– geografiska annaler: series a, physical geography, 94, 135–156. doi: 10.1111/j.1468‐0459.2012.00454.x bostjančić, i., filipović, m., gulam, v & pollak, d. (2021): regional-scale landslide susceptibility mapping using limited lidar-based landslide inven­ tories for sisak-moslavina county, croatia.– sustainability, 13, 4543. doi: 10.3390/ su13084543 burns, w.j. & madin, i.p. (2009): protocol for inventory mapping of landslide de­ posits from light detection and ranging (lidar) imagery.– special paper 42, oregon department of geology and mineral industries, 30 p. chacon, j., irigaray, c., fernandez, t. & el hamdouni, r. (2006): engi­ neering geology maps: landslides and geographical information systems.– bulletin of engineering geology and the environment, 65, 341–411. doi: 10.1007/s10064006-0064-z cred, unisdr (2018): economic losses, poverty & disasters 1998-2017.– available at https://www.preventionweb.net/files/61119_credeconomiclosses.pdf [accesed 20.07.2021.] ćirić, b. (1967): neotektonska karta sfr jugoslavije 1:1500000 [neotectonic map of sfr of yugoslavia 1:1500000 – in croatian].– federal geological institute, belgrade. dai, f.c., lee, c.f. & ngai, y.y. (2002): landslide risk assessment and management: an overview.– engineering geology 64, 65–87. doi: 10.1016/s00137952(01)00093-x ershov, v.v., novikov, a.a. & popova, g.b. (1988): fundamentals of geology.– mir publishers, moscow, 358 p. fell, r., corominas, j., bonnard, c., cascini, l., leroi, e. & savage, w.z. (2008): guidelines for landslide susceptibility, hazard and risk zoning for land use planning.– engineering geology, 102/3–4, 85–98. doi: 10.1016/j.eng­ geo.2008.03.022 guzzetti, f., cesare mondini, a., cardinali, m., fiorucci, f., santan­ gelo, m. & chang, k.t. (2012): landslide inventory maps: new tools for an old problem.– earth-science reviews, 112/1–2, 42–66. doi: 10.1016/j.earsci­ rev.2012.02.001 hećimović, i. (2009): klastične naslage (pliokvartar pl, q) [clastic deposits (plio quaternary pl, q), in croatian]. in: velić, i. & vlahović, i. (eds.): tumač geološke karte republike hrvatske 1:300000, croatian geological survey, zagreb, 141, 94–95. huggett, r.j. (2017): fundamentals of geomorphology.– routledge, abingdon, 579 p. indrawan, i.g.b., rahardjo, h. & leong, e.c. (2006): effects of coarsegrained materials on properties of residual soil.– engineering geology, 82, 154– 164. doi: 10.1016/j.enggeo.2005.10.003 jaboyedoff, m., oppikofer, t., abellán, a., derron, m.-h., loye, a., metzger, r. & pedrazzini, a. (2012): use of lidar in landslide investi­ gations: a review.– natural hazards, 61, 5–28. doi: 10.1007/s11069-010-9634-2 jebur, m.n., pradhan, b. & tehrany, m.s. (2014): optimization of landslide conditioning factors using very high-resolution airborne laser scanning (lidar) data at catchment scale.– remote sensing of environment, 152, 150–165. doi: 10.1016/j.rse.2014.05.013 jurak, v., matković, i., miklin, ž. & cvijanović, d. (1998): landslide haz­ ard in the medvednica submountain area under dynamic conditions.– in: marić, b., lisac, z. & szavits-nossan, a. (eds.): geotechnical hazards, xith dan­ ube-european conference on soil mechanics and geotechnical engineering, poreč, croatia. kearey, p. (2001): the new penguin dictionary of geology.– penguin group, london, 327 p. li, y., chen, g., tang, c., zhou, g. & zheng, l. (2012): rainfall and earthquakeinduced landslide susceptibility assessment using gis and artificial neural net­ work.– natural hazards and earth system sciences, 12, 2719–2729. doi: 10.5194/ nhess-12-2719-2012 lukić, t., bjelajac, d., fitzsimmons, k.e., marković, s.b., basarin, b., mlađan, d., micić, t., schaetzl, r.j., gavrilov, m.b., milanović, m., sipos, g., mezősi, g., knežević-lukić, n., milinčić, m., létal, a. & samardžić, i. (2018): factors triggering landslide occurrence on the ze­ mun loess plateau, belgrade area, serbia.– environmental earth sciences, 77, 519. doi: 10.1007/s12665-018-7712-z mccalpin, j. (1984): preliminary age classification of landslides for inventory map­ ping.– proceedings of the annual symposium on engineering geology and soil engineering, 21, moscow, idaho, 99–120. mihalić, s., oštrić, m. & vujnović, t. (2008): landslide susceptibility mapping in the starca basin (croatia).– proceedings of 2nd european conference of inter­ national association for engineering geology, 2008, madrid, spain. novosel-škorić, s., magdalneić, z. & korolija, b. (1986): pliokvartarni sedimeneti jugoistočnog dijela krndije – sjeverna hrvatska [plioquaternary sedi­ ments of the southeastern part of krndija northern croatia in croatian].– geološki vijesnik, 39, 11–18. park, t.-w., kim, h.-j., tanvir, m.t., lee, j.-b. & moon, s.-g. (2018): influence of coarse particles on the physical properties and quic undrained shear strength of fine-grained soils.– geomechanics and engineering, 14/1, 99–105. doi: 10.12989/ gae.2018.14.1.099 perkins, c.r. & parry, r.b. (1990): information sources in cartography guides to information sources.– bowker-sour, london. pike (1988): the geometric signature: quantifying landslide terrain types from digital elevation models.– mathematical geology, 20/5, 491–511. reichenbach, p., rossi, m., malamud, b.d., mihir, m. & guzzeti, f. (2018): a review of statistically-based landslide susceptibility models.– earthscience reviews, 180, 60–91. doi: 10.1016/j.earscirev.2018.03.001 roser, m., ritchie, h. & ortiz-ospina, e. (2013): world population growth. –published online at ourworldindata.org. retrieved from: ‘https://ourworldin­ data.org/world-population-growth’ [accessed 13.07.2021.] savezni geološki zavod (1962): uputstvo za izradu osnovne geološke karte fnrj [instructions for making a basic geological map – in croatian].– savezni geološki zavod, beograd, 99 p. schuster, r.l. (1996): socioeconomic significance of landslides.– in: turner, a.k. & schuster, r.l. (eds.): landslides: investigation and mitigation.– spe­ cial report 247, transportation research board, national research council, na­ tional academy press, washington, dc, 12–35. shakoor, a. & cook, b.d. (1990): the effect of stone content, size, and shape on the engineering properties of a compacted silty clay.– environmental and engi­ neering geoscience, xxvii/2, 245–253. doi: 10.2113/gseegeosci.xxvii.2.245 shan, j. & toth, c.k. (2009): topographic laser ranging and scanning principles and processing.– taylor & francis group, llc, new york, 654 p. šikić, k. (1995): prikaz geološke građe medvednice.– in: šikić, k. (ed.): geološki vodič medvednice. institut za geološka istraživanja, ina-industrija nafte, zagreb, 7–30. šikić, k., basch, o. & šimunić, a. (1977): osnovna geološka karta rh 1:100000, list zagreb l38−80 [basic geological map of sfry 1:100000, zagreb sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. šikić, k., basch, o. & šimunić, a. (1979): osnovna geološka karta sfrj 1:100000. tumač za list zagreb l38−80 [basic geological map of sfry 1:100000, geology of the zagreb sheet – in croatian].– institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd, 75 p. uppal, s. (2006): fundamentals of physical geography.– national council of educa­ tional research and training, new delhi, 136 p. van den eeckhaut, m., poesen, j., verstraeten, g., vanacker, v., nyssen, j., moeyersons, j., van beek, l.p.h. & vandekerckhove, l. (2007): use of lidar-derived images for mapping old landslides under for­ est.– earth surface processes and landforms, 32, 754–769. doi: 10.1002/esp.1417 varnes, d.j. & iaeg (1984): landslide hazard zonation: a review of principles and practice.– iaeg commission on landslides and other mass movements, natural hazards 3, unesco, paris, 63 p. vrsaljko, d., pavelić, d., miknić, m., brkić, m., kovačić, m., hećimović, i., hajek-tadesse, v., avanić, r. & kurtanjek, n. (2006): middle miocene (upper badenian/sarmatian) palaeoecology and evolu­ tion of the environments in the area of medvednica mt. (north croatia).– geolo­ gia croatica, 59/1, 51–63. vrsaljko, d., hećimović, i. & avanić, r. (2007): miocene deposits of northern croatia.– in: grgasović, t. & vlahović, i. (eds.): 9th international sympo­ sium on fossil algae croatia, field trip guidebook and abstracts, croatian geo­ logical survey, zagreb, 143–153. zezere, j.l., de brum ferreira, a. & rodrigues, m.l. (1999): the role of conditioning and triggering factors in the occurrence of landslides: a case study in the area north of lisbon (portugal).– geomorphology, 30, 133–146. doi: 10.1016/ s0169-555x(99)00050-1 2016 | 69/2 | 175 | www.geologia-croatica journal of the croatian geological survey and the croatian geological society dear colleagues, it is our pleasure to present you a selection of palaeontological papers dedicated to the great lady, our late professor vanda kochansky-devidé (10th april 1915 – 26th february 1990), who was the first female full-member of the croatian (and formerly yugoslav) academy of sciences and arts. vanda kochansky-devidé graduated with a degree in biology from the faculty of philosophy in zagreb. after graduation she was employed at the university of zagreb, faculty institute of geology and palaeontology, where she spent all her working career. generations of students remember her excellent lectures and exceptional drawing skills. her textbook in palaeontology is still in use among students and active geologists. hard-working and excellent teacher, professor kochansky was respected in the wider community. one of croatian magazines put her on the list of twenty most influential women in the croatian society. her wide research interest influenced many palaeontologists, including the authors of papers published in this issue of geologia croatica. her first research papers were dedicated to the neogene macrofossils. she was the first geologist to develop micropalaeontology in croatia, and determined microfossils from different geologic periods and localities all over the world. vanda kochansky-devidé published more than one hundred scientific papers as well as numerous professional and popular issues. she was the author of numerous new fossil taxa, and many palaeontologists named their newly found fossils after her. she was the initiator and coauthor of the first geological bibliography, the chief editor of several scientific magazines, a member of many professional associations, and she was active in geoheritage protection and geoconservation. she was awarded several times for her professional achievements, and she became 100th birth anniversary of professor vanda kochansky-devidé doi: 10.4154/gc.2016.22 the full-member of the yugoslav academy of arts and sciences in the year 1973. croatian palaeontologists from different geological institutions gathered together and organized an international meeting dedicated to the 100th birth anniversary of professor vanda kochansky-devidé from 9th to 11th april 2015. meeting included the opening ceremony in the croatian academy of sciences and arts (hazu), exhibition in the croatian natural history museum, one-day excursion to the neogene localities in the vicinity of zagreb, and lecture/poster sessions at the faculty of science, university of zagreb. this issue comprises several scientific papers which were presented at the meeting in 2015 in the form of lectures and posters. we hope that all our activities related to the 100th birth anniversary of professor vanda kochansky-devidé will help keeping the memory on vanda alive, and help younger generations of geologists and palaeontologists to uncover the personality and scientific opus of this exceptional woman. additionally, this issue meets traditional and new methods in geology research. except for five paleontological papers it includes some of new research studies dealing with the application of innovative technologies for landslide detection and application of statistical analysis in economic geology. results of geochemical analysis were processed by factor analysis for surface hydrocarbon exploration and in with the purpose of identifying the influence of parent material, mining industry and agriculture on the groundwater. also, the discriminant model is constructed in order to assess apply the geochemistry of lower palaeogene bauxites as a tool for unravelling the unique signature of the tectonostratigraphic evolution. jasenka sremac, issue editor lidija galović, editor-in-chief 2018 | 71/2 | 83–90 | 3 figs. | 3 tabs. | 1 app. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction in many small islands in the oceans and seas composed of hydraulically permeable geologies, freshwater lenses are the only source of abundant freshwater supply for the residents and others, as well as for agriculture that is often an important industry on these islands. such groundwater resources are known or at least considered to be susceptible to natural and anthropogenic threats such as long-term unprecedented sea-level rise, extended drought, and over-abstraction (e.g., terry & chui, 2012; ishida et al., 2015; barkey & bailey, 2017). understanding the hydraulic properties of aquifers is essential for appropriate management of the groundwater resources that are both vital and vulnerable. one conventional method for studying the hydraulic properties of an aquifer is a pumping test. however, this is not always the best approach for a freshwater-lens aquifer for several reasons, including the following: (i) when a pumping test is conducted within an area where fresh groundwater is underlain by saltwater, as an environmental concern, the pumping may cause an upflow of the underlying saltwater that can contaminate the freshwater resource, and (ii) when the test is alternatively conducted at a site close to the coastline avoiding the fresh-groundwater distribution, technologically, the analysis of the pumpingtest data requires some strategies to compensate for large tidal disturbances common in such locations (jha et al., 2003; chattopadhyay et al., 2015; houben & post, 2017). heterogeneous hydraulic properties of an insular aquifer clarified by a tidal response method with simple decomposition techniques katsushi shirahata, shuhei yoshimoto, takeo tsuchihara and satoshi ishida naro institute for rural engineering, tsukuba, ibaraki 305-8609, japan (shirahatak@affrc.go.jp) doi: 10.4154/gc.2018.06 abstract two simple frequency decomposition techniques were used as part of a tidal response method to derive the hydraulic diffusivities of a freshwater-lens aquifer. digital high-pass filtering can separate the tidal components of diurnal and shorter periods from longer-period components. discrete fourier transform can be used to isolate a specific tidal component. these techniques are easy to practice using the built-in functions of spreadsheet software. the applied techniques were each optimized for the frequencies of known major tidal components. isolation of the specific tidal signals helps to reduce the errors of a basic tidal response method that uses in its calculations the amplitude attenuation and phase lag of a simple sinusoidal wave of groundwater fluctuations. another advantage of the present tidal method is the utilization of two groundwater time series collected from near-shore and relatively inland sites affected by the same ocean tide. the method does not use surface-water observation, thus avoiding errors derived from generally possible surface-water/groundwater boundary effects. the tidal response method with simple decomposition techniques was used to investigate the aquifer properties of an uplifted limestone island located in a subtropical region of japan. a freshwater lens is the principal water resource for this island and its sustainable development is desired. significant hydraulic layering has not been reported in the limestone aquifer. pairs of groundwater-level time-series data collected by simultaneous observations at near-shore and inland sites were analysed by the tidal response method. the results demonstrated heterogeneous aquifer diffusivity on the island, typically with larger values in the southeastern coastal part than in the northwestern coastal part, which is consistent with the planar distribution of the entire freshwater lens and the position of its maximum thickness that are slightly biased toward the northwestern side. in studies of the hydraulic properties of aquifers bearing water affected by tidal oscillations, tidal methods have found worldwide application (e.g., carr & van der kamp, 1969; krivic, 1982; almeida & silva, 1983; koizumi et al., 1998; trefry & jhonston, 1998; corbett et al., 2000; banerjee et al., 2008; alcolea et al., 2009; carol et al., 2009; fadili et al., 2012; martin et al., 2012; austin et al., 2013; rotzoll et al., 2013; jo et al., 2014; perriquet et al., 2014; yang et al., 2015; nieto lópez et al., 2016; guo et al., 2017). the methods analyse the natural tidal oscillations observed in groundwater height or pressure propagated from adjacent surface waters, and do not require anthropogenic pumping. analysis of the natural tidal response of groundwater fluctuations gives a general idea of the aquifer hydraulic parameters (perriquet et al., 2014) and would be an appropriate and convenient approach for studying a freshwater-lens aquifer. shirahata et al. (2014) used a tidal response method with a simple decomposition technique, following a fundamental calculation procedure for discrete fourier transform to extract or isolate four known major tidal components. they used a groundwater-level observation time series covering 369 days, a length optimized for the periods of the four major tides. shirahata et al. (2016) suggested the use of nonrecursive digital filters to separate a semidiurnal to diurnal tidal-period band from a longerperiod weather band prior to the quantitative analysis of tidal components. shirahata et al. (2017) added appropriate time article history: manuscript received december 15, 2017 revised manuscript accepted april 23, 2018 available online june 21, 2018 keywords: freshwater-lens aquifer, nonrecursive digital filtering, discrete fourier transform, tidal response method, hydraulic heterogeneity g eo lo gi a c ro at ic a geologia croatica 71/284 series lengths for the isolation of major tidal components, the shortest of which was 29.5 days, based on examination of artificially synthesized various time series. the purpose of the present work was (i) to confirm the validity of nonrecursive digital filtering, simple discrete fourier transform, and their integration with a tidal response method, suggested by the recent studies mentioned above, through application to observation time series of real coastal groundwater, and (ii) to estimate the hydraulic properties of the island’s aquifer where sustainable development of a freshwater lens has long been desired. 2. hydrogeological outline of the study island tarama island is one of the ryukyu islands that comprise part of the japanese islands. the oval-shaped island measures about 5.8 km × 4.3 km with an area of approximately 19.8 km2 (fig. 1). most of the land area is 5–15 m above sea level (a.s.l.). in the eastern part of the island, an approximately n-s lineament is clearly detected in satellite and aerial photos, with a difference in ground elevation of roughly several metres observed in the field (higher on the east side). the lineament is thought to be a fault line with an approximately vertical fault plane (yazaki, 1977). tarama island is dominated by quaternary limestone several tens of metres thick underlain by fine-grained sandstone (ooga et al., 1974; ohzeki et al., 2014). the limestone is hydraulically highly permeable with a reported hydraulic conductivity range of 1.05×10−2 to 2.91×10−2 m/s based on a pumping test conducted on the island (yamada et al., 2009). the exact site of the pumping test is not known. significant hydraulic layering has not been reported in the limestone aquifer. the underlying fine-grained sandstone is regarded as practically impermeable, judging from the results of in situ permeability tests conducted in investigations by the okinawa general bureau, cabinet office of japan. estimated hydraulic conductivities were in the order of 10–8 to 10–6 m/s. contour lines of roughly estimated elevations of the top surface of the sandstone are, in principle, drawn concentrically with the highest part near the centre of the island and the lower part in the surrounding coastal area, so as to be consistent with test drilling records where the top of the sandstone was reached (fig. 1a). the water table averages several decimetres a.s.l. in the central part of the island. the thickness of the limestone aquifer on this island is roughly estimated as 35 m near the centre of the island and more than 60 m in the coastal area, except within the eastern part of the fault. the above descriptions of the hydrogeological structure of the island are mostly based on unpublished results of investigations conducted by the local branch of the national administrative office in charge of this area. owing to the extended permeable limestone, rainwater readily percolates down into the ground and provides no surface water on tarama island, except where runoff water on paved surfaces is artificially collected and stored in agricultural ponds. naturally, groundwater is the principal freshwater resource of the island. a freshwater lens is the source of domestic-water supply for a population of about 1200 residents. on the other hand, the local branch of the national administrative office is investigating the groundwater resource to make a general plan for agricultural and rural development with an appropriate combination of surface-water and groundwater resource development. the freshwater lens covers an area of roughly 10 km2 and is about 7 m thick at its maximum (shirahata, 2010; ishida et al., 2011) (fig. 1b). the horizontal positions of the whole freshwater lens and the maximum thickness are slightly offset to the northwestern side of the island. 3. time-series data collection as described by shirahata et al. (2017) and referred to later in this paper, the present tidal response method requires a pair of sites for groundwater observations with different distances to the tidal surface water. the present study used time-series data previously reported by shirahata et al. (2014). the groundwaterlevel data were collected from five observation sites, one of which is located only 0.02 km inland from the south-southwestern edge of the island (site a) and four others are located further inland at distances of 1.0 to 1.3 km to each nearest coastline of the eastsoutheastern, southern, western, and north-northwestern sides of the island (sites b, c, d, and e, respectively) (fig. 1b). the four 1 m 2 m 3 m 4 m5 m 6 m 7 m 6 m 5 m 1 m 1 m 1000 m n site a b c d e b 1000 m n 40 m bsl 33.6 m 38.1 m 39.2 m 49.0 m 50.8 m bsl 50 m 60 m 40 m a figure 1. estimated contour map of the top surface of the impermeable sandstone basement beneath the limestone aquifer of tarama island (a) and the distribution of the freshwater lens in the aquifer (b). (a) the map of the basement is made by tracing contour lines from a map created in investigations by the okinawa general bureau, cabinet office of japan, a map in accordance with test drilling records at five sites (crosses in the map, with the elevations of the top surface of the basement below sea level). (b) the isopachs of the freshwater aquifer (measured ec less than 200 ms/m) are based on measurements taken on 1st october 2008, previously partly drawn by shirahata & nagata (2009). solid circles are locations of the groundwater-level observation holes, sites a through e, where time-series data were collected. dotted lines represent the shortest paths from the respective observation sites to the coastline, indicating the expected propagation paths of tidal waves observed in the groundwater fluctuations. g eologia c roatica shirahata et al.: heterogeneous hydraulic properties of an insular aquifer clarified by a tidal response method with simple decomposition ... 85 inland sites were each paired with the near-shore site as required for the tidal response method used and four pairs of sites were made (a/b, a/c, a/d, a/e). it was assumed both in the study by shirahata et al. (2014) and here, as an approximation, that the tidal oscillations of groundwater levels 0.02 km inland of the above four coastlines nearest to the inland observation sites are identical to the oscillations at the near-shore observation site. hourly sampled time-series data were collected from june 2008 to july 2009 at groundwater-observation holes using submersible water-level data loggers with a built-in sensor. shirahata et al. (2014) showed in their figs. 5 and 6 the time-series charts of the observed groundwater levels. the time series included 1to 3-h data gaps or missing data on rare occasions. data gaps with a length of 1 h or one data point in the time series were filled with the average of the previous and next data values. digital filtering and fourier transform were applied to consistently hourly time-series data after filling the gaps. 4. frequency decomposition techniques and tidal response method the decomposition techniques and tidal response method employed in the present study are explained below. the simple discrete fourier-transform technique was used in two different steps for different aims. first it was used to make frequency spectra of the groundwater fluctuations. then the technique was utilized to provide amplitude and initial phase of one desired tidal component, which were subsequently used in formulae to calculate aquifer diffusivity. the two procedures of the fourier transform are described separately, with an explanation of digital filtering in between. the basics of the techniques for discrete fourier transform and digital filtering are also mentioned. 4.1. fourier transform to produce spectra with the amplitudes of major tides major tidal components, called “tidal constituents,” are identified by the frequency or period of the sinusoidal tide-generating potentials. shirahata et al. (2014) utilized a fourier technique for isolation of the top four major tidal constituents, m2, k1, s2, and o1, from 8856-h-long hourly time-series data. the isolation means the determination of the amplitude and initial phase of the sinusoidal tidal oscillations. the technique simply followed (part of) the fundamental formulae for discrete fourier transform and was completed using spreadsheet software with built-in functions for trigonometric calculations, averages, square roots, and other basic operations (appendix). the appropriate choice of length of the transformed time series is essential for accurate isolation of the desired tidal components of specific frequencies. there are several recommendable combinations of the transformed timeseries lengths and isolated major tidal constituents for the simple fourier-transform technique (shirahata et al., 2017). in the present study, year-long time-series data collected at sites a, b, c, and e were firstly subjected to the fourier transform to describe the frequency compositions of the groundwater fluctuations. the data of site d were not employed because they contained unfilled 2and 3-h-long data gaps. simple fourier transform of 8856-h-long data from 2008-7-1 0:00 to 2009-7-4 23:00 was performed to produce a spectrum that exhibits amplitudes at the approximate or exact frequencies of major tides o1, p1, k1, m2, s2, and k2. in the obtained spectrum, tidal frequencies will be indicated on the horizontal axis by integers n used in the transform calculations, the integers for divi ding the time-series length (8856) to give quotients close to the specific periods of the tidal components (shirahata et al., 2017). for example, the amplitude for the m2 frequency will be shown at n = 713, because the period 12.420601 h is very closely approximated by the quotient 8856 divided by 713. in the same manner, the amplitudes for the frequencies of major tidal constituents o1, p1, k1, s2, and k2 will be shown at n = 343, 368, 370, 738, and 740, respectively. to supplement the measurement of the amplitude of another major tide, n2 constituent (period: 12.658348 h), 9924-h-long time-series data from 2008-6-12 0:00 to 2009-7-30 11:00 were also transformed. in the spectrum, the amplitudes for the n2 and m2 frequencies will be shown at n = 784 and 799, respectively. 4.2. nonrecursive digital filtering to remove long-period components digital filters are used to separate out fluctuation components with a desired range of frequencies from discrete-time timeseries data. the digital filter employed in the present study is a nonrecursive type. in other words, one data point of the filtered output discrete time series is calculated by the linear combination of terms of a number sequence that is a finite-length portion of the input time series. the multiplication coefficients of the linear combination comprise the number sequence that represents the applied digital filter. nonrecursive digital filtering of electromagnetic time-series data with a constant sampling interval is easily achieved using standard spreadsheet software with a built-in function for calculating the sum of the products of the corresponding terms of two number sequences. shirahata et al. (2016) provided a further introduction to nonrecursive digital filtering and concrete examples of conventional and new digital filters for tidally fluctuated time-series data. the high-pass filter used in the present study is the reverse of the “lp241h079122km3” low-pass filter made by shirahata et al. (2016). the employed high-pass filter removes components with periods longer than 2 days, but accurately preserves in the output hourly time series the major diurnal and semidiurnal tidal constituents (q1, o1, p1, k1, n2, m2, s2, and k2) contained in the input hourly time series. this filter has a length of 241 terms or hours and outputs time series shorter than the finite input time series by 10 days. groundwater-level time-series data of the five observation sites underwent the filtering. because the subsequent fourier transform requires data covering 29.5 days, segments of 39.5-day-long time series were selected to be filtered. two segments were extracted from the time series of each observation site. from the data acquired at five sites from late 2008 to early 2009, the time series from 2008-9-6 0:00 to 2008-10-15 11:00 and the time series from 2009-1-11 0:00 to 2009-2-19 11:00 were extracted. these segments of time series were selected because of the absence of data gaps in the raw data and the relatively large disturbance of water levels caused by the weather, namely atmospheric pressure changes, in order to clearly demonstrate the effect of digital filtering. 4.3. fourier transform to isolate a tidal constituent for tidal response method the simple fourier-transform technique was again used to isolate a tidal component for the tidal response method from short timeseries data of the five observation sites. in the present step to isolate a tidal constituent, part of the calculations for the fourier transform, to determine one component, was utilized. transform of time series with a length of 708 h, the shortest of the time-series lengths that shirahata et al. (2017) recommended, was g eo lo gi a c ro at ic a geologia croatica 71/286 adopted and m2 constituent was isolated. ten time-series segments of the five observation sites, each 708 h long after shortened by 240 h by high-pass filtering, were transformed to give the amplitudes and initial phases of the oscillations of m2 constituent contained in the groundwater fluctuations. table 1 summarizes the time-series data subjected to fourier transform in the two steps described above (see 4.1. for the first step). each transformed time series is specified by a combination of the observation site and the start and end of the transformed period. distances of the observation sites to each nearest coastline are also shown. the distances were used in the tidal response method explained in the following section. 4.4. basic tidal response method to derive aquifer hydraulic diffusivity two basic formulae rearranged from ferris (1951) were used in this study (shirahata et al., 2017): d = (π/t)·(xb − xa)2/(ln(ha/hb))2 and d = (π/t)·(xb − xa)2/(δω)2 , where d is the desired hydraulic diffusivity of the aquifer (equal to the ratio of transmissivity t to storage coefficient s, or to the ratio of conductivity k to specific storage ss) [m2/s], t is the period of the tidal constituent under consideration [s], xa and xb are the distances of the near-shore site and inland site nearest to each boundary with the same tidal surface water (xa < xb) [m], ha and hb are the constituent amplitudes at the near-shore site and inland site (ha > hb) [m], and δω is the phase lag of the inland site to the near-shore site (δω > 0) [rad]. in the present case, the period t in the formula was set to 44714.164, the period of m2 constituent in units of seconds. tidalamplitude ratio (ha/hb) and phase shift (δω) for m2 constituent were calculated from the outputs of the simple fourier transform of the 708-h-long time series of the paired two sites. for each pair of near-shore and inland sites, four diffusivity values were calculated from the two different segments of time series using the two formulae above. the four values were averaged to derive a definitive aquifer diffusivity for the pair of observation sites. 5. results 5.1. major tidal components in water fluctuations figure 2 shows amplitude-frequency spectra obtained from the time series of groundwater levels at site a using the simple fourier-transform calculations. in the spectrum of the 8856-h-long time series (fig. 2, top panel), it is shown that the fluctuations contain large signals of semidiurnal tidal constituents, especially m2 with an amplitude of 0.466 m (at n = 713). the second-largest component with an amplitude of 0.196 m at n = 738 corresponds to s2 constituent. the amplitude for the frequency of k2 constitu ent (n = 740) is 0.068 m. a rise in the spectrum around n = 700 with a peak amplitude of 0.063 m corresponds to n2 tide, but the amplitude for n2 frequency is not directly shown in this spectrum produced from the 8856-h time series. instead, using the fourier transform of the 9924-h time series (fig. 2, bottom panel), the amplitude for the n2 frequency (n = 784) was determined as 0.087 m. diurnal tidal components are relatively insignificant with amplitudes of 0.174, 0.055, and 0.191 m for the frequencies of o1, p1, and k1 (n = 343, 368, and 370 in the spectrum of the 8856-h time series), respectively. table 2 lists the amplitudes for the frequencies of the major diurnal and semidiurnal tidal constituents estimated by the fourier transform of time series of specified lengths. as an example of the inland sites, groundwater fluctuations at site c have signals for the frequencies of o1, p1, k1, n2, m2, s2, and k2 constituents with amplitudes of 0.026, 0.006, 0.027, 0.005, 0.029, 0.011, and 0.005 m, respectively. the diurnal tidal oscillations were attenuated compared to the near-shore site (a) with amplitude ratios between 11% and 16%, whereas for semidiurnal constituents the amplitude ratios were between 5% and 7%. among the inland sites (b, c, and e) with similar distances to the coast (see table 1), the amplitudes of the constituents at site b, the eastern site, are four to eight times those at site e, the northwestern site. this indicates heterogeneity in the hydraulic properties of the aquifer of the island, which is quantitatively elucidated later. 5.2. effects of digital filtering and tidal-component isolation on time series figure 3 exemplifies the effects of digital filtering and isolation of a major tidal component. it shows the sets of time-series line charts of the original groundwater-level observation data, lowpass-filtered and high-pass-filtered data, and the chart of the isolated m2 constituent, the latter reproduced from the outputs of the 708-h fourier transform, for sites a and d. the digital filtering effectively separated semidiurnal to diurnal tidal signals (“high-passed”) from longer-period changes (“low-passed”). specifically, as an example of the longer-period changes, the lowpassed data of site a (fig. 3, top panel) reveals two rises, each a few days long with peaks on the 12th and 28th september that were unclear from the original data chart. the rises coincided with the approach of typhoons no. 13 and no. 15 of this year, retable 1. observation sites and periods of fourier-transformed time-series data. site closer side / distance to coast transformed period to produce spectrum transformed period to isolate m2 start / end (yyyy-m-d hh:) start / end (yyyy-m-d hh:) start / end (yyyy-m-d hh:) start / end (yyyy-m-d hh:) a ssw 2008-7-1 00: 2008-6-12 00: 2008-9-11 00: 2009-1-16 00: 0.02 km 2009-7-4 23: 2009-7-30 11: 2008-10-10 11: 2009-2-14 11: b ese 2008-7-1 00: 2008-6-12 00: 2008-9-11 00: 2009-1-16 00: 1.07 km 2009-7-4 23: 2009-7-30 11: 2008-10-10 11: 2009-2-14 11: c s 2008-7-1 00: 2008-6-12 00: 2008-9-11 00: 2009-1-16 00: 1.05 km 2009-7-4 23: 2009-7-30 11: 2008-10-10 11: 2009-2-14 11: d w 2008-9-11 00: 2009-1-16 00: 1.24 km 2008-10-10 11: 2009-2-14 11: e nnw 2008-7-1 00: 2008-6-12 00: 2008-9-11 00: 2009-1-16 00: 1.22 km 2009-7-4 23: 2009-7-30 11: 2008-10-10 11: 2009-2-14 11: g eologia c roatica shirahata et al.: heterogeneous hydraulic properties of an insular aquifer clarified by a tidal response method with simple decomposition ... 87 spectively. the intensive low-pressure system would have affected the water table of the permeable island through the intermediary of changes in height of the surrounding surface water (vacher, 1978a). for all five sites a through e, including not shown, line charts of the original data, high-passed data, and the isolated constituent generally match the timing of periodic peaks and troughs, demonstrating that the digital filtering and fourier transform of 708-h-long time series successfully isolated the desired m2 constituent. 5.3. aquifer hydraulic parameters table 3 lists aquifer diffusivities calculated by the tidal response method using amplitudes and initial phases of the m2 constituent isolated from the 708-h-long time series. the aquifer diffusivities are close to the values previously derived from the 8856-h time 0.0 0.1 0.2 0.3 0.4 0.5 1 101 201 301 401 501 601 701 801 am pl itu de (m ) n (frequency = n/8856 cph) site a, 8856-h time series n = 738: s2 0.196 m n = 713: m2 0.466 m n = 700 0.063 m n = 370: k1 0.191 m n = 368: p1 0.055 m n = 343: o1 0.174 m n = 740: k2 0.068 m 0.0 0.1 0.2 0.3 0.4 0.5 1 101 201 301 401 501 601 701 801 901 am pl itu de (m ) n (frequency = n/9924 cph) site a, 9924-h time series n = 799: m2 0.466 m n = 784: n2 0.087 m figure 2. frequency spectra of groundwater-level fluctuations at site a produced using the simple fourier-transform technique. the two panels show spectra obtained from 8856and 9924-h-long time series. frequencies in cycles per hour (cph) are given by the quotients of the integers n on the horizontal axis divided by the transformed time-series length (8856 or 9924). table 2. amplitudes of major tidal constituents determined using fourier transform of 8856and 9924-h-long time series. site time-series length amplitude of tidal constituent (m) o1 p1 k1 n2 m2 s2 k2 a 8856 h 9924 h 0.174 0.055 0.191 0.087 0.466 0.466 0.196 0.068 b 8856 h 9924 h 0.036 0.009 0.038 0.008 0.045 0.044 0.017 0.007 c 8856 h 9924 h 0.026 0.006 0.027 0.005 0.029 0.030 0.011 0.005 e 8856 h 9924 h 0.009 0.002 0.008 0.001 0.006 0.006 0.002 0.001 figure 3. examples of sets of time-series line charts of the original groundwater-level observation data, low-pass-filtered data, high-pass-filtered data, and the chart of isolated m2 constituent. top and bottom panels display sets of data of sites a and d, respectively. -2 -1 0 1 2 3 -3 -2 -1 0 1 2 9/6 00:00 9/11 00:00 9/16 00:00 9/21 00:00 9/26 00:00 10/1 00:00 10/6 00:00 10/11 00:00 w at er le ve l ( m ) w at er le ve l ( m a sl ) site a year 2008 original data (left axis) low-passed (left axis) high-passed (right axis) isolated m2 (right axis) -0.4 -0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 9/6 00:00 9/11 00:00 9/16 00:00 9/21 00:00 9/26 00:00 10/1 00:00 10/6 00:00 10/11 00:00 w at er le ve l ( m ) w at er le ve l ( m a sl ) site d year 2008 original data (left axis) low-passed (left axis) high-passed (right axis) isolated m2 (right axis) g eo lo gi a c ro at ic a geologia croatica 71/288 ssary to at least increase the number of case studies using the present method, including application to confined aquifers. the definitive diffusivity of the east-southeastern part of the aquifer (represented by the result for the pair of sites a/b) is two to three times that of the northwestern part of the aquifer (a/e pair). this difference is beyond the variations of the tentative diffusivities. the same magnitude relationship naturally holds for the estimated conductivities. this relationship is clearly consistent with the areal distribution of the freshwater lens offset to the northwestern side of the island (fig. 1b), in a similar way to the case of bermuda island presented by vacher (1978b). 7. concluding remarks this paper reported examples of applying simple techniques for processing tidally fluctuated groundwater time-series data, one to separate highand low-frequency signals and the other to isolate known major tidal components. the techniques were further used as part of a simple tidal response method that has recently been improved for application to relatively short observation data. the improved method combined with the two decomposition techniques was first applied to real groundwater observation data in the present work. the method provided convincing hydraulic parameters that compare well with the result of a pumping test and are consistent with the distribution of the freshwater lens on the study island. the present results showed the heterogeneity of the hydraulic properties of the aquifer on the island, which is now being used as the basis for the investigation of sustainable groundwater development on the island. the techniques and method are easy to practice using the built-in functions of standard spreadsheet software and are highly applicable to digitally recorded observation time-series data. they should be useful for investigating aquifer hydraulic properties in insular and coastal areas where groundwater is often the principal, or sometimes the only, water resource. acknowledgement the authors are grateful to the land improvement general office and the successive officers for policy planning in the land improvement division of the okinawa general bureau, cabinet office of japan for their support and collaboration in field and desk research. thanks are also due to local government officials and residents of tarama island for their understanding and cooperation in the field study. this work was partly supported by a research project funded by the ministry of agriculture, forestry and fisheries of japan (development of mitigation and adaptation technologies to climate change in the sectors of agriculture, forestry, and fisheries, 91150), and also by jsps kakenhi grant no. 17k08011. series (shirahata et al., 2014). this confirms the validity of the present method based on the analysis of 708-h time series. the definitive aquifer diffusivities for the four pairs of sites a/b, a/c, a/d, and a/e, determined as the average of the four tentative values, range from 6.1 to 15.5 m2/s. assuming the storage coefficient of the limestone aquifer of this island as roughly 0.1, referring to the value used in public works on a neighbouring island to construct underground dams in the contemporaneous limestone formation, and assuming the aquifer thickness as roughly 55 m, based on the contour map of the top surface of the underlying impermeable stratum drawn in investigations by the national administrative office, hydraulic conductivities are calculated as 1.1×10−2 to 2.8×10−2 m/s. 6. discussion the estimated hydraulic conductivities using the present method fall in the same order of magnitude as the range of values based on a pumping test referred to earlier (1.05×10−2 to 2.91×10−2 m/s; yamada et al., 2009). unfortunately, the result of the pumping test was only briefly mentioned, and the exact test location is unpublished. it is impossible to make a detailed comparison between the results from the present tidal response method and the previous pumping test. although there seems to be nothing amiss with observation data or the isolation of a tidal constituent (5.2.), the tentative hydraulic diffusivities for each site pair show a consistent bias; diffusivities derived from the amplitude ratio are smaller than those from the phase lag. the same tendency is found in the results of shirahata et al. (2014), who used a tidal response method based on 8856-h time-series fourier decomposition. thus, the detected bias does not imply a defect specific to the present method based on 708-h time-series data. among previous studies using tidal response methods, the same bias between attenuation-based and lag-based aquifer parameters, with much more significance than that of the present case, is reported by erskine (1991), who attributed the variations in the calculated aquifer parameters to the damping effect of a phreatic surface on fluctuation amplitudes. the same bias, to an extent slightly lesser than that of erskine (1991), is also detected by trefry & bekele (2004) between the amplitude attenuation and time delay of tidal signals in their study aquifer. they deduced that the less than ideal relationship between the attenuation and delay was due to horizontal layering in the aquifer properties. in the present study, there is no definitive evidence as to the reason for the difference in the tentative hydraulic diffusivities for each site pair, but the effect of a phreatic surface or unreported hydraulic layering is a possible cause. to elucidate the reason, it would be necetable 3. aquifer hydraulic diffusivities estimated by the simple tidal response method using m2 constituent isolated by fourier transform of 708-h-long time series. site pair length / location start of time series (near-shore / inland) of target aquifer (yyyy-m-d hh:) m2 amp m2 ip m2 amp m2 ip derived from amp derived from ip 1.05 km 2008-9-11 00: 0.440 6.048 0.043 3.885 14.4 16.6 15.5 / ese 2009-1-16 00: 0.461 2.281 0.044 0.131 14.1 16.8 1.4 ( 9.0%) 1.03 km 2008-9-11 00: 0.440 6.048 0.028 3.564 9.9 12.1 10.8 / s 2009-1-16 00: 0.461 2.281 0.028 6.055 9.4 11.8 1.3 (12.4%) 1.22 km 2008-9-11 00: 0.440 6.048 0.023 3.497 12.0 16.1 14.1 / w 2009-1-16 00: 0.461 2.281 0.024 6.031 11.9 16.3 2.4 (17.4%) 1.20 km 2008-9-11 00: 0.440 6.048 0.005 2.208 5.1 6.9 6.1 / nw 2009-1-16 00: 0.461 2.281 0.006 4.764 5.3 7.0 1.0 (16.8%) amp: amplitude (m), ip: initial phase (rad), d: hydraulic diffusivity (m2/s), avg: average, sd: standard deviation (avg / 1 sd of left four) definitive dnear-shore site inland site tentative d a / b a / c a / d a / e g eologia c roatica shirahata et al.: heterogeneous hydraulic properties of an insular aquifer clarified by a tidal response method with simple decomposition ... 89 krivic, p. (1982): transmission des ondes de marée à travers l’aquifère côtier de kras [transmission of tidal waves across the coastal aquifer of kras – in french].– geologija, 25/2, 309–325. martin, j.b., gulley, j. & spellman, p. (2012): tidal pumping of water between bahamian blue holes, aquifers, and the ocean.– journal of hydrology, 416–417, 28–38. doi: 10.1016/j.jhydrol.2011.11.033 nieto lópez, j.m., andreo navarro, b. & mudarra martínez, m. (2016): hydrogeological parameters assessment by tidal influence analysis in the coastal aquifers of bajo guadalhorce (malaga province, southern spain) [in spanish, with an english abstract].– geogaceta, 59, 39–42. ohzeki, m., imai, r., takayanagi, h. & iryu, y. (2014): stratigraphy and geologic age of the ryukyu group on tarama-jima, ryukyu islands, japan [in japanese].– abstracts of the 121st annual meeting of the geological society of japan, r5-p-19. ooga, h., furukawa, h. ogura, i. & nishida, t. (1974): groundwater of tarama island, okinawa prefecture [in japanese].– abstracts of the 81st annual meeting of the geological society of japan, 368. perriquet, m., leonardi, v., henry, t. & jourde, h. (2014): saltwater wedge variation in a non-anthropogenic coastal karst aquifer influenced by a strong tidal range (burren, ireland).– journal of hydrology, 519b, 2350–2365. doi: 10.1016/j. jhydrol.2014.10.006 rotzoll, k., gingerich, s.b., jenson, j.w. & el-kadi, a.i. (2013): estimating hydraulic properties from tidal attenuation in the northern guam lens aquifer, territory of guam, usa.– hydrogeology journal, 21/3, 643–654. doi: 10.1007/ s10040-012-0949-9 shirahata, k. (2010): analysis of water balance in formation of freshwater lens through electric conductivity measurement [in japanese].– journal of the japanese society of irrigation, drainage and rural engineering, 78/6, 514–515. shirahata, k. & nagata, j. (2009): a study of freshwater lens in taramajima island for a large-scale water resource development in the future [in japanese].– geotechnical engineering magazine, 57/9, 42. shirahata, k., ishida, s., yoshimoto, s. & tsuchihara, t. (2014): new simple method for estimating hydraulic properties of a freshwater-lens aquifer by analysis of tidal groundwater fluctuations [in japanese, with an english summary].– technical report of the national institute for rural engineering, 215, 141–154. shirahata, k., yoshimoto, s., tsuchihara, t. & ishida, s. (2016): digital filters to eliminate or separate tidal components in groundwater observation timeseries data.– japan agricultural research quarterly: jarq, 50/3, 241–252. doi: 10.6090/jarq.50.241 shirahata, k., yoshimoto, s., tsuchihara, t. & ishida, s. (2017): improvements in a simple harmonic analysis of groundwater time series based on error analysis on simulated data of specified lengths.– paddy and water environment, 15/1, 19–36. doi: 10.1007/s10333-016-0525-3 terry, j.p. & chui, t.f.m. (2012): evaluating the fate of freshwater lenses on atoll islands after eustatic sea-level rise and cyclone-driven inundation: a modelling approach.– global and planetary change, 88–89, 76–84. doi: 10.1016/j.gloplacha.2012.03.008 trefry, m.g. & bekele, e. (2004): structural characterization of an island aquifer via tidal methods.– water resources research, 40/1, w01505. doi: 10.1029/2003wr002003 trefry, m.g. & jhonston, c.d. (1998): pumping test analysis for a tidally forced aquifer.– ground water, 36/3, 427–433. doi: 10.1111/j.1745-6584.1998.tb02813.x vacher, h.l. (1978a): hydrology of small oceanic islands-influence of atmospheric pressure on the water table.– ground water, 16/6, 417–423. doi: 10.1111/j.1745-6584.1978.tb03256.x vacher, h.l. (1978b): hydrogeology of bermuda–significance of an across-the-island variation in permeability.– journal of hydrology, 39/3–4, 207–226. doi: 10.1016/0022-1694(78)90001-x yamada, s., yonahara, n. & sobue, h. (2009): the quaternary coral reef complex deposits (ryukyu group) and hydrogeologic features on tarama-jima, okinawa prefecture, japan [in japanese].– abstracts of the 116th annual meeting of the geological society of japan, 83. yang, h., shimada, j., matsuda, h., kagabu, m. & dong, l. (2015): evaluation of a freshwater lens configuration using a time series analysis of a groundwater level and an electric conductivity in minami-daito island, okinawa prefecture, japan [in japanese, with an english abstract].– journal of groundwater hydrology, 57/2, 187–205. doi: 10.5917/jagh.57.187 yazaki, k. (1977): geology of the taramashima district [in japanese, with an english abstract].– geological survey of japan, kawasaki, 28p. references alcolea, a., renard, p., mariethoz, g. & bertone, f. (2009): reducing the impact of a desalination plant using stochastic modelling and optimization techniques.– journal of hydrology, 365/3–4, 275–288. doi: 10.1016/j.jhydrol.2008.11.034 almeida, c. & silva, m.l (1983): novas observações sobre o efeito de maré em aquíferos costeiros do algarve [new observations of the tidal effect in coastal aquifers of algarve – in portuguese, with an english abstract].– boletim da sociedade geológica portugal, 24, 289–293. austin, m.j., masselink, g., mccall, r.t. & poate, t.g. (2013): groundwater dynamics in coastal gravel barriers backed by freshwater lagoons and the potential for saline intrusion: two cases from the uk.– journal of marine systems, 123–124, 19–32. doi: 10.1016/j.jmarsys.2013.04.004 banerjee, p., sarwade, d. & singh, v.s. (2008): characterization of an island aquifer from tidal response.– environmental geology, 55/4, 901–906. doi: 10.1007/s00254-007-1041-y barkey, b.l. & bailey, r.t. (2017): estimating the impact of drought on groundwater resources of the marshall islands.– water, 9/1, 41. doi: 10.3390/w9010041 carol, e.s., kruse, e.e., pousa, j.l. & roig, a.r. (2009): determination of heterogeneities in the hydraulic properties of a phreatic aquifer from tidal level fluctuations: a case in argentina.– hydrogeology journal, 17/7, 1727–1732. doi: 10.1007/s10040-009-0478-3 carr, p.a. & van der kamp, g.s. (1969): determining aquifer characteristics by the tidal method.– water resources research, 5/5, 1023–1031. doi: 10.1029/ wr005i005p01023 chattopadhyay, p.b., vedanti, n. & singh, v.s. (2015): a conceptual numerical model to simulate aquifer parameters.– water resources management, 29/3, 771–784. doi: 10.1007/s11269-014-0841-6 corbett, d.r., dillon, k. & burnett, w. (2000): tracing groundwater flow on a barrier island in the north-east gulf of mexico.– estuarine, coastal and shelf science, 51/2, 227–242. doi: 10.1006/ecss.2000.0606 erskine, a.d. (1991): the effect of tidal fluctuation on a coastal aquifer in the uk.– ground water, 29/4, 556–562. doi: 10.1111/j.1745-6584.1991.tb00547.x fadili, a., mehdi, k., riss, j., malaurent, p.h., boutayeb, k. & guessir, h. (2012): oceanic tidal influence on the piezometric level variation of the coastal karst aquifer of oualidia (morocco) [in french, with an english abstract].– africa geoscience review, 19/3, 135–150. ferris, j.g. (1951): cyclic fluctuations of water level as a basis for determining aquifer transmissibility.– international association of scientific hydrology, publication 33, 148–155. guo, m., wan, j., jiang, f. & huang, k. (2017): estimating unconfined aquifer parameters based on groundwater tidal effect [in chinese, with an english abstract] .– earth science, 42/1, 155–160. doi: 10.3799/dqkx.2017.012 houben, g. & post, v.e.a. (2017): the first field-based descriptions of pumpinginduced saltwater intrusion and upconing.– hydrogeology journal, 25/1, 243–247. doi: 10.1007/s10040-016-1476-x ishida, s., tsuchihara, t., yoshimoto, s., minakawa, h., masumoto, t. & imaizumi, m. (2011): estimate of the amount of freshwater lens of tarama island, japan [in japanese, with an english abstract].– irrigation, drainage and rural engineering journal, 273, 7–18. ishida, s., yoshimoto, s., koda, k., kobayashi, t., shirahata, k. & tsuchihara, t. (2015): salt water intrusion into groundwater and problem on vava’u island and lifuka island, kingdom of tonga [in japanese, with an english abstract].– technical report of the national institute for rural engineering, 217, 1–12. jha, m.k., kamii, y. & chikamori, k. (2003): on the estimation of phreatic aquifer parameters by the tidal response technique.– water resources management, 17/1, 69–88. doi: 10.1023/a:1023018107685 jo, s.-b., jeon, b.-c., park, e.-g., choi, k.-j., song, s.-h. & kim, g.-p. (2014): estimation of hydraulic characteristics and prediction of groundwater level in the eastern coastal aquifer of jeju island [in korean, with an english abstract].– journal of environmental science international, 23/4, 661–672. doi: 10.5322/jesi.2014.4.661 koizumi, n., kitagawa, y., kazahaya, k. & takahashi, m. (1998): volcanic gas concentration and aquifer permeability estimated from tidal fluctuations in groundwater level: case of koshimizu well in izu-oshima, japan.– geophysical research letters, 25/12, 2237–2240. doi: 10.1029/98gl01409 g eo lo gi a c ro at ic a geologia croatica 71/290 appendix example of spreadsheet for isolation of four major tidal components from 8856-h-long time series, using part of the fundamental formulae for discrete fourier transform (shirahata et al., 2014). if comparable calculations are made for consecutive natural numbers, instead of only four numbers (343, 370, 713, 738) used in this spreadsheet, a fourier spectrum as shown in fig. 2 (top panel) can be made. 2022 | 75/1 | 35–49 | 14 figs. | 1 tab. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction landslides are one of the natural hazards that has a major impact on human lives. they cause major economic losses, but also direct loss of life, and are present worldwide. quantification of those losses is difficult and incomplete. according to the world health organization, between 1998 – 2013, landslides have caused more than 18.000 deaths and affected 4.8 million people (cred, 2018). the european environment agency (2010), reported 312 deaths due to 70 major landslides in the period of 1998–2009 in europe. haque et al. (2016) presented a spatiotemporal distribution of deadly landslides in 27 european countries over 20 years (1995–2014) with a total of 1370 deaths and an average economic loss of approximately 4.7 billion euros per year. all these studies are based on reports from major landslides, and all agree that the numbers are certainly underestimated as the majority of landslides are unreported. this is especially true for countries outside “global landslide hotspots” (himalayan arc, central america, etc.) with numerous landslides with catastrophic consequences (klose et al., 2015). according to klose et al. (2015), most of the landslides in germany are individually of smaller consequence, so are mostly unreported. however, when summarized and collated, the costs of those smaller events are higher than the combined major, 100-year events. once triggered, landslides can cause significant damage and loss of life. remediation of the affected slopes and infrastructure also brings significant costs. the most cost-effective means of reducing those costs is prevention. by identifying areas susceptible to landslides, urbanization can avoid or adapt to the condi use of a lidar-derived landslide inventory map in assessing influencing factors for landslide susceptibility of geological units in the petrinja area (croatia) tihomir frangen*, mirja pavić, vlatko gulam and tomislav kurečić croatian geological survey, sachsova 2, 10000 zagreb, croatia * corresponding author: tihomir.frangen@hgi-cgs.hr doi: 10.4154/gc.2022.10 abstract a landslide inventory was created for an area of 22.6 km2 near petrinja city in northern croatia, based on the high-resolution lidar data complemented by orthophoto maps. a total of 216 landslides were identified, covering 2.91 % of that area. landslide polygons were overlain on geological units based on the basic geological map of sfry at a scale of 1:100.000 that is the largest scale geological map available for the whole of croatia. the relationship between landslides and geological units was expressed as a landslide index. three geological units displayed increased landslide susceptibility. a pliocene unit clearly had the largest susceptibility, followed by a palaeocene-eocene unit, and finally a badenian unit. landslide density was analyzed within these geological units to identify influencing factors for landslide initiation. each geological unit revealed different influencing factors. the pliocene unit is mostly influenced by bedding plane orientation and local relief. heterogeneousness lithology is the dominant factor in the paleoceneeocene unit, while the badenian unit demonstrated the least certain interpretation as there are multiple factors involved. the forest road is presumed to be crucial, followed by spring occurrences and proximity to the tectonic boundary. the basic geological map of sfry proved to be a viable source of geological information for the creation of landslide susceptibility maps at a scale of up to 1:100.000, but with limitations in the case of lithologically heterogeneous geological units. larger scale maps require more detailed research as landslide susceptibility factors vary in each geological unit. tions, thus avoiding or at least significantly lowering the direct consequences of landslides (cascini, 2008). in that regard, landslide susceptibility maps are the simplest solution. by adding more information, landslide susceptibility maps can be upgraded to hazard or risk maps (hervás & bobrowsky, 2009). the first step in that process is development of a landslide inventory (wieczorek, 1983). landslide susceptibility maps should cover large areas in order to facilitate urban planning. for that purpose, the cost of producing such maps should be kept low. to achieve that, already existing data should be used as much as possible. that can be problematic, as it often implies combining data produced at different scales and for different purposes. as compromises must be made in that process, it is important to critically evaluate the given outputs. their final scale, reliability, purpose, and limitations should be clearly defined. in order to test the possibilities of assessing landslide susceptibility in croatia, influencing factors were assessed for a pilot area near the city of petrinja. it is one of six pilot areas in the safearth project (“transnational advanced management of land use risk through landslide susceptibility maps design”), which was carried out from 2017 to 2019 under the interreg ipa crossborder cooperation programme croatia-bosnia and herzegovina-montenegro 2014–2020. as there is no landslide inventory for the study area, one had to be created. in the scope of the safearth project, airborne laser scanning (als), also known as airborne light detection and scanning (lidar) was performed for an area of approximately 300 km2, including the study area article history: received october 07, 2021 revised manuscript accepted december 24, 2021 available online february 28, 2022 keywords: landslide inventory, lidar, landslide susceptibility, geological units, basic geological map, petrinja g eo lo gi a c ro at ic a geologia croatica 75/136 presented here. lidar is a well-known data source for derivation of a landslide inventory (jaboyedoff et al., 2012) and is especially well suited for forested areas (slatton et al., 2007), as in the study area, as it can penetrate the canopy and derive bare earth digital terrain models (dtm). besides the landslide inventory, an accurate and precise dtm derived from lidar data facilitates preparation of other required data, including slope, aspect, and relief energy. parallel to the lidar scanning, aerial photographs were taken that allowed construction of an orthophoto map which supplemented the lidar data in the analysis. besides the landslide inventory and lidar data derivatives, geology provides crucial data for assessing landslide susceptibili ty (van westen et al., 2008). for this purpose, geological data used was from the basic geological map of sfry 1:100.000 (pikija, 1987a), as it is the largest scale map available for the whole of croatia and the study area. its usefulness and limitations were tested, within the scope of geological units (gus) present in the study area. to this day, there is no universally defined method for deriving landslide susceptibility models (reichenbach et al., 2018). the reasons for this are many, from different geological, climatic, and physiographical settings to data availability and the purpose for deriving models. this study does not aim to change any of this, as it covers a small area with limited influencing factors. despite that, the aim is to guide future landslide investigations in the region, or similar areas, in methods of data usage, their influence, and limitations. 2. study area the study area is located in the northern part of croatia and is defined within the safearth project co-financed by interreg ipa cbc (croatia – bosnia and herzegovina – montenegro). it covers an area of 22.6 km2 (fig. 1). the study area belongs to sisačko – moslavačka county, sw of the petrinja city. it is bounded by the kupa, petrinjčica, and sanja rivers, north, east, and west, respectively. the river utinja flows in a se-nw direction towards the kupa river passing through the middle of the study area. the relief is characterized by smaller hills intersected by creek valleys, with an average height of 150-250 metres, with the highest peak being kosinjak (324 m a.s.l.). the climate is temperate continental under the mild influence of the mediterranean climate of the northern adriatic. the atmospheric conditions are very variable and intense exchanges of weather situations occur during the year (zaninović et al., 2008). the average monthly temperature ranges from -0.2 ° c for the lowest average (january) and 21.5 ° c as the highest average (june) for the nearest city of sisak for which data are available (for the period 1949 – 2019). for the same period of climate monitoring, the meteorological and hydrological service of croatia (dhmz) recorded the average precipitation amount being the lowest in march (55.1 mm) and highest in november (93.5 mm). the average annual temperature in the city of petrinja is 10.9 ° c (period 2013 – 2020, dhmz), while the average annual rainfall is around 1088.85 mm with a maximum of 1400 mm, measured at the closest meteorological station in sisak (over the period 1949–2019, dhmz). the sisak meteo station is located approx. 13 km in a direct line to the centre of the study area polygon. 2.1. geological settings the investigated area is located at the sw margin of the pannonian basin system (horváth et al., 2015; pavelić & kovačić, 2018) along the border of the sava depression (saftić et al., 2003). only the ne marginal part belongs to the neogene-quaternary tectonic unit of the sava depression, while the majority of the area belongs to the relatively elevated area of the tectonic unit of the inner dinarides (pikija, 1987a, 1987b). these large-scale structures are bordered by dinaric nw-seoriented fault systems. it is still a highly tectonically active area figure 1. the study area near petrinja. g eologia c roatica frangen et al.: use of a lidar-derived landslide inventory map in assessing influencing factors for landslide susceptibility of geological units ... 37 with numerous documented landslides triggered by earthquakes and neotectonic movements along the main faults (markušić et al., 2021; pollak et al., 2021). the area is almost completely covered with neogene-quaternary deposits with occasional occurrences of pre-neogene basement palaeogene rocks (pikija, 1987a). detailed lithological data concerning the deposits of the research area are scarce, due to the chronostratigraphic approach used when the newest geological map of the area was developed (pikija, 1987a). however, the basic lithology of the mapped units is given (pikija, 1987b) and described in the following text in chronostratigraphic order using original mapping nomenclature (fig. 2). palaeocene–eocene (pc,e): conglomerates, sandstones, siltstones, and sandy marls these deposits are exposed in the central part of the investigated area (fig. 2), along the hills surrounding the river utinja. according to pikija (1987b), the palaeocene-eocene complex in the wider area is represented by conglomerates intercalated with other lithological members, namely sandstones, siltstones, sandy marls, and limestones. the conglomerates are the most distributed lithology, they are polymictic with variable content of sandy matrix, and are mainly carbonate-free. the clasts originate from the upper cretaceous sediments, volcanic rocks, and pyroclastics from the vicinity. therefore, the clast composition varies. mafic effusive rocks, granite, gneiss, crystalline schists, metasandstones, chert, and sandstones were determined amongst others (pikija, 1987b). clasts are 1–20 cm in diameter, rarely 20–40 cm. an estimated thickness of the deposits is around 200 m. badenian (m22): conglomerates, sandstones, limestones, and marls badenian deposits are transgressive to older (palaeogene-eocene) sedimentary rocks in the southern parts of the investigated area (fig. 2). to the north, the badenian unit is in tectonic contact with surrounding gus or is mostly covered with the holocene alluvium of the river utinja. in the basal part, the badenian deposits are represented by an accumulation of coarse-grained sediments (conglomerates, gravel, sandstones, biocalcarenites). in the upper part of the sequence, fine-grained sediments predominate with increased carbonate content up to 98% (clays and marls, bioclastic and biogenic limestones) (pikija, 1987b). generally, the most prominent lithology within the badenian deposits is represented by shallow-water deposits i.e., reef and near-reef figure 2. geological map of the study area. g eo lo gi a c ro at ic a geologia croatica 75/138 facies deposits: lithothamnium, coralline-lithothamnium, and bryozoan-lithothamnium limestones, and forereef biocalcrudites and biocalcarenites. these deposits are characterized by high porosity (up to 45%). coeval deposited marls, limestone-marls and micritic limestones can also be observed in the area. the thickness of badenian sediments varies up to a maximum of 200 m. lower sarmatian (1m31): marls, limestones, conglomerates, and sands sarmatian deposits occur mostly in the sw part of the investigated area. they are continuously deposited onto badenian deposits (fig. 2). composed of various lithologies shallow and deepwater deposits can be observed. occasionally coarsegrained shallow water clastic rocks (polymictic conglomerates, conglomerate-sandstones, and gravelly sands) crop out, followed by shallow-water ooid limestones, marl-limestones, and calcarenites with porosity up to 40% (pikija, 1987b). in stagnant and deep-water environments, thin-plate and laminated deposits are developed, also with high lithological variability. marl predominates, followed by clayey limestones, and limestones. occasionally they are intercalated with sands and biocalcarenites. the thickness of the sarmatian deposits in the wider area is estimated to be up to 70 m. lower pannonian (1m31,2): limestones and marls lower pannonian deposits comprise a thin belt following the zone with sarmatian deposits along the sw part of the investigated area (fig. 2). they are represented by facies of thin-bedded limestones, and marls. deposited continuously on the lower sarmatian deposits, thin-bedded micritic limestones or silty limesto nes are homogenous with a carbonate content of between 85 and 95% (pikija, 1987b). marls and limestone-marls are partly laminated (resembling the sarmatian deposits) with carbonate contents between 50 and 80%. the thickness of the lower pannonian deposits in the area could be estimated as between 20–50 m. upper pannonian (2m31,2): marls upper pannonian deposits cover most of the sw part of the investigated area. deposited conformably on the lower pannonian deposits (fig. 2), they show lithological similarities with the underlying unit (pikija, 1987b). a gradual decrease in the carbonate content is observable. the majority of the unit is composed of yellow to brown/gray massive marls (35–75% carbonates) or rarely clayey marls. the overall thickness of the upper pannonian deposits can reach 200 m. pliocene (pl2,3): clay, silt, gravel, sand, sandstones, conglomerates, lignite pliocene deposits occupy the ne part of the investigated area (fig. 2). they are discordantly deposited on the basement composed of various units, such as pc/e, and badenian deposits, and are overlain by quaternary dpr and alluvial sediments (pikija, 1987a) covering the largest area of the investigated polygon. these deposits known as the viviparus beds are widely distributed in the sw part of the pannonian basin (kurečić et al., 2021; mandic et al., 2015; neumayr & paul, 1875; rundić et al., 2016). pliocene deposits are mostly clastic and heterogenous: sands, gravel, silts, and clay with a general coarsening upwards trend, and occasionally conglomerates and lignite. in the nearby area of the vukomeričke gorice (toward the nw) pliocene deposits can be divided into five basic lithofacies units: facies of massive and normally graduated gravels, facies of cross stratified sands and gravelly sands, facies of massive and laminated sands, facies of clay silts, and heterolithic facies (kurečić, 2017). quartz is the most dominant constituent of the sand, lithic fragments are less common, ranging from 13-54%, while feldspar grains are the least represented (kurečić et al., 2021). sandstones (lithoarenites) are limonitized and form thin interlayers within the sand. occasionally polymictic conglomerates can be observed. the well-rounded clasts are up to 1 cm in diameter, composed of radiolarian chert, silicified vitreous tuff, quartzite, and quartz schist. the thickness of the deposits in the area has been estimated as 200–400 m (pikija, 1987b). plio-quaternary (pl, q): gravel, sands, and clay pliocene-quaternary deposits occur only sporadically, lying discordantly over various older lithological units (fig. 2). in the area, they are composed of sand, gravel, clay, and rarely sandstones and conglomerates (pikija, 1987b). sands and gravels predominate in the area. finer-grained sediments are commonly moderately sorted, occasionally fine quartz sands occur (up to 96% sio2, pikija 1987b). there is great variability of sediment mixtures ranging from clayey sands to gravelly sands and gravels with rounded pebbles up to 3 cm in diameter. gray to brown clayey sediments occur in form of lenses and thin layers within sands. those sediments are mineralogically similar to the pliocene sediments with the predominance of zircon, tourmaline, epidote, and rutile within the heavy mineral fraction. pebbles in gravel consist of chert, pyroclastics, and sandstones. lithified deposits occur only rarely. the estimated thickness of the unit is up to 100 m. holocene (dpr): diluvial-proluvial silt, sand, and gravel those poorly sorted and chaotic sediments occur only in thin zones along the contact zone of valleys and hills in the ne part of the investigated area. the composition of sediments is closely related to the composition of the source rocks in the close vicinity. the thickness of the dpr sediments is estimated at 10 m (pikija, 1987b). holocene (a, a1, ap): alluvial sand, gravel, silt and clay on the ne edge of the investigated area, there are occurrences of the river kupa terrace sediments (a1). building up flat areas, these sediments consist mostly of silt, intertwined with sand and gravel layers (pikija, 1987b). sporadically, there are also occurrences of floodplain clayey-sandy silts (ap) with a maximum thickness of up to 5 m. sediments of recent alluvium (a) are associated with the river utinja. they show a variable granulometric composition in the range from silt to gravel, mineralogically reflecting the local drainage area. according to the area zonation by the degree of stability, on the engineering geological map of the sfry at a scale of 1:500.000 (čubrilović et al., 1967), the largest part of the study area is defined as a “prevailing unstable area under natural conditions and under the man’s action mostly unstable”. the lesser part is defined as “prevailing stable area under natural conditions while under the man’s action they can be prevailingly unstable”. only flat, alluvium areas are defined as stable areas. 3. data and methods the basis of this study was lidar data that will be explained in detail in the next section. lidar, along with its derivatives and together with orthophotos, was used for creating the landslide inventory. 3.1. remote sensing data sets the basis of this study is lidar data acquired during the safearth project. data acquisition was performed using a helig eologia c roatica frangen et al.: use of a lidar-derived landslide inventory map in assessing influencing factors for landslide susceptibility of geological units ... 39 copter, during the spring of 2018, by flycom technologies d.o.o. lidar used for the acquisition was riegl lms-q780 and for rgb photographs a hasselblad h60 camera with 50 mm lens was used. ground control points were utilised for assuring the specified accuracy. laser scanning produced a point cloud with a minimum point density of 20 points per m2. the accuracy of every point was in the range of ±10 cm in each direction. full waveform data were recorded which facilitated the separation of the ground from vegetation (mallet & bretar, 2009). the described point cloud was used for deriving a digital terrain model (dtm) with a cell size of 0.5 x 0.5 m. the dtm represents bare earth, stripped of vegetation and all man-made objects, and is therefore suitable for analysis of landslides and other morphological processes (razak et al., 2011). photographs that were taken with an rgb camera were corrected with elevation data derived from lidar. this produced orthophoto maps with 0.1 x 0.1 m pixel size. lidar-derived dtm was used for the creation of several derivatives useful for terrain visualization, and hence, landslide mapping: 1. hillshade grid – shaded relief in the same resolution as dtm. two grids were produced with different positions of the light source. the position of the first light source was an azimuth of 315° and 45° elevation. the other had the same elevation, but the azimuth was 45°. combining them enabled landslides to be spotted in all orientations. 2. slope angle grid – a slope angle of the terrain was also produced at a resolution of 0.5 x 0.5 m. it was represented in a continuous colour scale as that enabled the best visual representation of the terrain. 3. aspect grid – used for obtaining the exact orientation of every cell. resolution was also 0.5 x 0.5 m. 4. contour lines – contours with equidistance of 1 m were used for visual help in recognizing changes in the slope shape due to landslides. 3.2. creation of a landslide inventory the landslide inventory was created for the area that was covered with lidar data, as that was the source of input data for landslide detection. all lidar derivatives described in the previous subchapter were used in 2d using esri arcmap 10.2 software and in 3d using esri arcscene software. landslides were contoured subjectively, using expert judgment (guzzetti et al., 2012). to avoid differences in a subjective approach, the whole inventory was created by one expert. in this way, all inaccuracies due to bias were the same across the whole inventory. all visible morphological signs of a landslide were evaluated. for an area to qualify as a landslide, at least 50% of its boundary length had to be recognizable (main scarp, lateral flanks, toe). the internal body of a landslide has to show some signs of movement (undulated terrain, cracks, minor scarps, water pooling, etc.). the whole area with material displacement was contoured, regardless of whether the material was carried away or deposited (from the top of the main scarp to the bottom of the toe). all landslides in the inventory were given a grade, on a scale of 1 to 10.a lower-grade indicates a landslide with less pronounced features and overall lower reliability. in contrast, a higher grade indicates more pronounced features with higher reliability, which also implies more recent activity. grades 9 and 10 are reserved for landslides with clearly visible features on all datasets (lidar and orthophoto). since the area is forested over a large part, most landslides are not visible on orthophotos, unless they are very recent. lower grades of 1 and 2 are used for areas with subdued landslide features and a possibility that they are wrongly interpreted as landslides. in the areas with overlapping landslide bodies, or multiple landslide generations, each polygon was delineated separately, where possible. each landslide body is unique, and no overlapping is allowed. 3.3. geological data gus used for analysis are almost exclusively from the basic geological map of sfry at a scale of 1:100.000 (pikija, 1987a). that data was used because it is the largest scale geological map available for the whole of croatia and the only one that covers the entire study area. although there are some obvious inaccuracies in it, (inevitably due to the small scale and available technology at the time of production), there have been no corrections applied to it, as one of the goals of this study is an assessment of their use in landslide susceptibility assessment in the croatian territory. 3.4. fieldwork fieldwork was carried out on two occasions. the purpose of the first fieldwork was the verification of the landslide inventory made exclusively with lidar data. verification has been done on the easternmost part of the area. a second field trip was targeted at specific areas, which had anomalies in the number of landslides that could not be resolved using only gis analysis, or needed field verification of the presumed explanations. 3.5. gis analysis all of the afore-mentioned data were aggregated in gis using esri arcgis 10.2 with spatial analyst software. lidar-derived data were analyzed using standard arcgis tools. depending on the aims and purpose, data were extracted for different target groups (gus, landslides, landslides in specific gus). basic statistical analysis was undertaken on such extracted data sets. landslides were classified into five groups based on their area in square metres (šestanović, 2001): very small (< 100 m2 ), small (100 – 1,000 m2), moderate (1,000 – 10,000 m2), large (10,000 – 50,000 m2) and very large (> 50,000 m2). 3.5.1. landslide index the landslide index is calculated as a ratio between landslide area in a given gu and the area of that gu and is expressed as a in percentage. it shows relationships between the gus and landslide occurrence within the study area. it was also calculated for the entire area for comparison (bartelletti et al., 2017; conforti & ietto, 2020). 3.5.2. local relief the map of local relief represents the maximum difference in elevation for the unit area (bucci et al., 2016; conforti & ietto, 2020; della seta et al., 2004; molin et al., 2012). historically, the unit area used was 1 km2. in more recent times, the unit area varies depending on the intended usage and the author’s preferences. in this study, a local relief map was produced using the focal statistics tool in arcgis. with it, for each cell in a raster, the maximum range in elevation was determined in a circle with a radius of 250 m. the radius was chosen based on the approximate average slope length in the study area. g eo lo gi a c ro at ic a geologia croatica 75/140 3.5.3. aspect and slope aspect and slope angle were calculated for each landslide body as an average of all the cells in it. they were also calculated for the whole area of each gu, on the basis of 5 x 5 m cells. additionally, for each 5 x 5 m cell, dip direction and dip angle were calculated and their poles were analyzed in stereonet 1.1 software (allmendinger et al., 2011; cardozo & allmendinger, 2013). due to hardware processing limitations, a subset of 10000 random cells was extracted from a gu. their poles were projected on a stereonet and their density was shown using the kamb contouring method (kamb, 1959). in addition, the mean vector was calculated to get the average orientation of the slopes in a particular gu. 4. results 4.1. inventory analysis the investigated polygon, covered by lidar around petrinja, has an area of 22.57 km2. the total area of landslides in that polygon is 0.66 km2, or 2.91 % of the total area, spread over 216 landslides. the average landslide density is 9.6 landslides per km2. the number of landslides based on their area is shown in fig. 3. the smallest landslide has an area of 59 m2 and the largest 51,673 m2. they are the only landslides belonging to the very small and very large landslide classes, respectively. small landslides represent 44.9 % of the total and the majority belong to the moderate area class at 48.1 %. in accordance with this, the avera ge and median landslide area also falls into the moderate size class, with 3,047 m2 and 1,156 m2, respectively. large area landslides represent only 6 % of all landslides. based on a landslide appearance in the lidar data, each landslide was given a grade in the range of one to ten. a higher grade indicates a more recent, active landslide while low grades imply old and uncertain landslides. none of the landslides were assigned to grade ten. roughly half of the landslides belong to the first two categories. generally, the number of landslides tapers down with each higher grade (fig. 4). figure 3. frequency density and the cumulative number of landslides considering landslide area. figure 4. landslide distribution based on the grade. g eologia c roatica frangen et al.: use of a lidar-derived landslide inventory map in assessing influencing factors for landslide susceptibility of geological units ... 41 the size of the individual landslides is quite uniform across the grades, although the largest landslides are mostly related to lower grades (fig. 5). the dominant aspect of the landslides is towards northeast, north, and northwest (fig. 6). 4.2. geological units of eleven gus in the studied area, five of them do not have any recognizable landslides, and two of them have only one landslide. the majority of landslides are situated in pl2,3 gu, which is also the most widespread (36.9% of surface area) (table 1) (fig. 7). table 1. landslide statistics for each geological unit. a ap dpr a1 pl,q pl2,3 2m3 1,2 1m3 1,2 1m3 1 m2 2 pc,e geological unit area (km2) 1.16 0.03 1.31 0.58 0.35 8.32 3.32 1.45 1.70 3.12 1,23 geological unit area ratio (%) 5.14 0.13 5.8 2.57 1.55 36.85 14.7 6.42 7.53 13.82 5.45 no of landslides 1 182 1 3 16 13 no of landslides, grade 1-3 1 96 1 1 12 9 no of landslides, grade 4-6 65 2 2 4 no of landslides, grade 7-9 21 2 landslide index 1.4 6.7 0.2 0.1 0.9 4.2 average slope in geological unit 6.8 3.8 6.0 3.4 8.3 9.9 8.7 10.1 11.2 20.6 19.8 average landslide slope in geological unit 12.1 15.5 14.6 24.0 22.1 20.4 average landslide area (m2) 18601.8 3044.6 2436.2 475.9 1840.8 4019.7 figure 5. landslide area for all grades. figure 6. distribution of landslides based on the dominant aspect of the landslide body. g eo lo gi a c ro at ic a geologia croatica 75/142 based on the results, only three gus were used for further analysis. those are the pliocene unit (pl2,3), palaeocene–eocene unit (pc,e), and the badenian unit (m2 2). although the holocene diluvial–proluvial unit (dpr) has a relatively high landslide index, it was omitted from further analysis as that index results from only one landslide which raised the landslide index as it covers a large area. however, it is situated on the boundary with the pliocene unit, so there is a large possibility that it belongs to that unit. verification was impossible since the area is suburban and covered with regolith and vegetation. the average slope angle of landslides in the three separated gus is presented in fig. 8. 4.2.1. pl2,3 unit the pliocene unit has 182 registered landslides, which is 84% of all landslides in the study area, while the gu covers 36.85% of the studied area. with 6.7% of its surface area covered by landslides, it has the biggest landslide susceptibility of all gus in the area. overlaying landslide density on a local relief map shows increased values of local relief in areas with landslides (fig. 9). in pliocene deposits, the average local relief value in the landslide area is 60.5 m, while it is only 37.4 m in the area without landslides. analysis of slope and landslide aspect shows the pronounced inclination of landslides towards the northeast (fig. 10). at the same time, the slope aspect has a much more homogenous orientation, with a slight inclination towards the north and south. projecting poles of 5 x 5 m cells of all slopes in this gu, we get a fairly homogeneous spread over all orientations. this is further confirmed by the mean vector with the pole dip direction of 196.6° and dip angle of 88.9°, so there is only a slight tendency of terrain sloping towards the north – northeast (fig. 11a). in the case of slope cells within landslides, there is a pronounced inclination towards the northeast. the mean pole vector of all cells has a dip direction of 209.1° and a dip angle of 83° (fig. 11b). the same analysis has been undertaken with bedding planes orientation of the pliocene strata. as the area is mostly covered by regolith and vegetation, bedding planes are hard to recognize, there are only eight measured layers in the literature in this area and four of them are horizontal (pikija, 1983, 1987a). therefore, these results should be taken with caution. however, they show figure 7. landslide area distribution in different geological units with corresponding landslide index. figure 8. average slope angle of landslides in three geological units. g eologia c roatica frangen et al.: use of a lidar-derived landslide inventory map in assessing influencing factors for landslide susceptibility of geological units ... 43 figure 9. local relief map of the study area, with the three analyzed geological units and landslide density. figure 10. aspect comparison of 5 x 5 m cells in the whole study area, cells in landslide bodies, and aspect of landslides represented with only one dominant aspect. g eo lo gi a c ro at ic a geologia croatica 75/144 a clear general inclination of bedding planes towards the northeast, with a mean vector pole dip direction of 214° and dip angle of 83.8° (fig. 11c) 4.2.2. pc,e unit although the palaeocene-eocene unit contains only 13 landslides, it still has a high landslide index of 4.2 as it is represented by 1.23 km2 (5.45% of the whole area). furthermore, it is split into two distinct parts. one is in the eastern part of the investigated area, the other is in the western part. all but one landslide are situated in the eastern part (fig. 9). a field investigation determined that although both areas belong to the pc,e chronostratigraphic unit, their lithology is different. the eastern part is composed of sandstones and siltstones while the western part is dominated by conglomerates (fig. 12). 4.2.3. m22 unit the badenian unit is the second-ranked gu in regards to the number of landslides, containing 16 landslides. however, with a 3.12 km2 surface area, the badenian unit covers 13.82% of the investigated area, hence, its landslide index is relatively low at 0.9. that puts it below the landslide index of the whole investigated area, which is 2.9. looking at fig. 9, it is clar that landslides are not uniformly spread in the badenian unit. there is an obvious hotspot in the easternmost part of the investigated area. while the badenian unit is not lithologically homogenous, the observed difference in landslide density cannot be attributed to lithological variation. the area affected by landslides has a limestone lithology (fig. 13a), which would imply lower landslide figure 13. scarp of the landslide in the regolith of the badenian limestones geological unit (a) and a channel formed from the road runoff water that leads to a landslide body below the road (b). figure 12. two different lithology types of palaeocene-eocene strata. sandstones and siltstones (a) and conglomerates (b). figure 11. stereonet diagrams of (a) slopes in the whole area covered by pliocene strata, (b) only cells within landslide bodies in the pliocene strata, (c) bedding planes. the mean vector is shown for each case. g eologia c roatica frangen et al.: use of a lidar-derived landslide inventory map in assessing influencing factors for landslide susceptibility of geological units ... 45 density as limestones form thinner regolith, with less clay content and more sharp-edged limestone fragments. after field investigation, several contributing factors were recognized. the dominant one is a forest road which is in direct contact with the majority of the landslides (fig. 13). it disturbed the mass balance by cutting into the slope and affected the slope by concentrating the drainage of runoff water from the road surface (fig. 13b). another possible contributing factor is the geological boundary with pc,e gu, together with spring occurrences alongside it (fig. 14b). there is no available data for the construction of the forest road. it cannot be seen on the orthophoto map from 1968. (fig. 14c). there are also no visible landslides, but since the area is forested, it cannot be concluded that there are none present. orthophoto map made during the year 2018 clearly shows the forest road and one landslide can be recognized (fig. 14d). 5. discussion 5.1. landslide inventory the leading principle in this study is that slope failures are more likely to occur under similar conditions that led to past instability (aleotti & chowdhury, 1999; carrara et al., 1991; guzzetti et al., 2000; guzzetti et al., 1999; mccalpin, 1984). in that regard, landslide inventory maps are a crucial component in determining areas susceptible to slope instabilities. deriving a landslide inventory from lidar data is a well-established method (booth et al., 2009; jaboyedoff et al., 2012; pawluszek, 2019; petschko et al., 2016; razak et al., 2011; schulz, 2007; schulz & schulz, 2004; van den eeckhaut & hervás, 2012). the resolution of lidar data enables an unprecedented level of detail, even in forested areas (görüm, 2019; slatton et al., 2007). inventory in this study lacks information on the triggering time. it is a geomorphological historical inventory in which the age of the landslides is not known (guzzetti et al., 2012; malamud et al., 2004). landslides are given a grade, which is influenced by age, but also other factors including human impact, erosion intensity, type of movement, etc. (bell et al., 2012; mccalpin, 1984). since environmental conditions change over time, older landslides might not be relevant to today’s conditions. however, determining the landslide age and appropriate criteria for the exclusion of certain landslides is difficult to determine and should be a topic of further investigation. the grades given to landslides are not used for analysis, but are useful for evaluating confidence in the results. the main criteria for choosing relevant landslides were visibility of at least half of their boundary. however, it is hard to evaluate the validity of that condition. although there are many slopes with signs of creeping movement, they are left out of the inventory and further analysis, as they do not have a defined boundary (cruden & varnes, 1996) and delineating creeping movements proved to be very subjective. landslides in the studied area are predominantly moderate and small in area. the largest landslides are mostly related to lower grades and that can have multiple explanations. one possibility is that the conditions in the past were different from today, so there was a tendency for bigger landslides. if that is the case, that landslides would be best left out of the landslide susceptibility analysis. however, it is also possible that they represent multiple smaller landslides, with mutual boundaries masked by erosion. therefore, leaving them out of analysis would cause a figure 14. maps of the investigated area: (a) dtm of the whole area with the extent of the badenian geological unit with large landslide density indicated; (1) extent of maps in parts b, c, and d, (2) pliocene geological unit, (3) badenian geological unit, (4) pc,e geological unit; (b) engineering geological map; (5) landslide, (6) spring, (7) captured spring, (8) road, (9) normal geological boundary, (10) fault, (11) assumed fault, (12) quaternary alluvium unit, (13) pliocene unit, (14) badenian unit, (15) palaeocene-eocene unit. g eo lo gi a c ro at ic a geologia croatica 75/146 significant underestimation of landslide susceptibility. differentiation of these two cases is problematic. in the absence of conclusive evidence for attributing lower grade landslides to different conditions in the past, it is safer to include them in the analysis. 5.2. geological units gus are a crucial element in landslide formation as they supply materials of different properties. however, determining their influence is often problematic. the most common geological information in landslide susceptibility models consists of chronostratigraphic units in the bedrock, as shown on standard geological maps (reichenbach et al., 2018). as stated in reichenbach et al. (2018), that approach may be problematic as the relationship between chronostratigraphic units and mechanical properties of materials involved in landsliding may be unclear. chronostratigraphic units may contain a variety of lithological formations with different mechanical properties. this problem can be seen in this study, in the case of pc,e gu, where there are two distinct lithologies with different landslide susceptibilities. since the majority of landslides in the inventory are shallow, translational earth slides (cruden & varnes, 1996), they are mostly originating in the regolith (allaby, 2020). although regolith composition is dependent on the bedrock, it can deviate from it, especially near geological boundaries or in the case of rugged terrain. there is also a scale discrepancy. geological maps used for analysis are at the scale of 1:100.000, while lidar data is equivalent to scale 1:1.000 (tobler, 1987). such a big difference inherently leads to errors, especially if the fact is ignored. with all of these problems, it is justifiable to evaluate the worthiness of using the basic geological maps of sfry 1:100.000 for landslide susceptibility maps. despite all the aforementioned problems, there are no other geological maps at a larger scale, which cover the entire region. especially if we consider evaluating landslide susceptibility for the whole of croatia. although gus in it are chronostratigraphic, lithological units are differentiated in some instances. in many chronostratigraphic units, the lithological composition is similar enough for combining their mechanical properties. while that is not an optimal source of geological data input for landslide susceptibility, it is viable if all the above problems are addressed. a preferred method for addressing such issues is fieldwork, as demonstrated in this study. as that is not always feasible, remote sensing methods could be applied in an attempt to differentiate lithologies or refine geological boundaries, but that has to be evaluated for each case. a possibility of other, more suitable geological maps for problematic areas should also be investigated. in summary therefore, due caution is needed in interpreting the landslide susceptibility of gus in the studied area. in the studied area, the pliocene gu has by far the most landslides and the most area coverage. the landslide index is also highest for the pliocene unit. it can be concluded that the pliocene gu is the unit most susceptible to landslides in the given area. judging by the landslide index, which takes into account the number of landslides in relation to the overall area, the palaeocene-eocene gu has the second-highest landslide susceptibility. the badenian gu has more landslides, but over a larger area, hence its landslide index is lower. it has to be noted that the number of landslides and area of both of these gus is low, hence the reliability of this interpretation is also low. all other gus in the study area cover a small area, or have only a few or no landslides. therefore, no conclusions in regards to landslide susceptibility can be made for those units. one of those gus is pl,q which is known for high landslide susceptibility (jurak et al., 1998), but has no landslides in the study area. since it is represented by an area of only 0.35 km2, it is recommended that it be disregarded from landslide susceptibility evaluation. furthermore, due caution is advised with the miocene units: 2m3 1, 1m3 1,2, 1m3 1. with zero, one, and three landslides per unit respectively, they leave an impression of a relatively stable area. it has to be noted that the average slope angle in those gus is around 10° (table 1). comparing that to the gus with a larger number of landslides, the badenian and palaeocene-eocene units are much steeper with approximately 20°. only the pliocene unit has a similar average slope, and the most landslides in the study area, which confirms it as the most landslide susceptible gu. comparing slope angle in landslide bodies, for gus with more than ten landslides, the badenian units are the steepest, palaeocene-eocene unit somewhat less steep, and the pliocene substantially less (fig. 8). this reflects the mechanical properties of materials in the respective gus, which are weakest in the palaeocene unit, as landslides are triggered in less steep slopes. slope in landslide bodies also correlates with the landslide index for those gus, with a higher landslide index indicating weaker mechanical properties. concentrating further on the three gus with more than ten landslides (pliocene, palaeocene-eocene, and badenian), it can be seen that landslides are not evenly spread over their respective areas (fig. 9). however, the causes of this are unique for each gu. 5.2.1. pc,e unit the simplest case is in the palaeocene-eocene unit. although it is one chronostratigraphic unit, it consists of two lithological units with different mechanical properties. the western part has only one landslide as it is composed of conglomerates that have a very thin regolith. the eastern part is composed of various clastic rocks such as sandstones and siltstones. they have a significantly lower mechanical strength and durability, and therefore are likely to develop a thicker regolith with less sharp-edged fragments. differentiating those two lithologies is difficult without fieldwork. determining landslide susceptibility for the whole gu, without considering different lithologies, could provide substantial inaccuracies. since there is no better source for geological data available for the whole of croatia, discarding the basic geological map would not be rational. however, landslide susceptibility should be limited to a small scale, reflecting the quality of the input data (van westen et al., 2008). if a large scale is needed, a further investigation that will differentiate lithological units is mandated. 5.2.2. m22 unit the badenian unit also has two distinct lithological units within it. while the initial assumption for the uneven spread of landslides was that same lithological differentiation, fieldwork disproved this. although limestones have better mechanical properties and durability than marls, sandstones, and poorly cemented conglomerates, they produce enough regolith with sufficient thickness for landslide formation. despite this, there are not many landslides developed in the whole badenian unit, except an area in the easternmost part of the unit (fig. 14). field investigation revealed the forest road as the main cause. most of the landslides are positioned near the road or in contact with it. there is a clear connection with landslides and cutting into the slope or associg eologia c roatica frangen et al.: use of a lidar-derived landslide inventory map in assessing influencing factors for landslide susceptibility of geological units ... 47 ated with runoff water from the road surface. there are no records for the time of activation for these landslides. since other factors including the proximity of the tectonic boundary with the palaeocene-eocene unit and spring occurrences are present, no definitive trigger can be identified. it could be that the combination of all the aforementioned factors in the same area is responsible for a large number of landslides. examples like this are hard to predict, especially on smaller scales. roads can be a significant factor in landslide activation, but done with proper drainage, they can be stabilizing factors in the slope. differentiating those two cases is difficult with the available data. while occurrences of groundwater and springs in connection with landslides are well established (anbalagan, 1992; getachew & meten, 2021; gökceoglu & aksoy, 1996), their relationship is not straightforward. the majority of larger springs have no connections with landslides. the most common, landslide-inducing springs, are very small. as such, they are unmarked on topographical maps. locating them is time-consuming and not practical for larger areas. locations of the springs in this example are predetermined by geological setting. specifically, contact of the permeable badenian limestones with non-permeable palaeocene-eocene deposits. while determining groundwater level is crucial for any single landslide investigation, establishing it for a wide area is difficult and often unattainable. 5.2.3. pl2,3 unit the pliocene gu is the dominant unit in the study area, in both the number of landslides and area coverage. it also exhibits contrasting landslide densities (fig. 9) and again, it is hard to resolve the primary reason for it. figure 10. shows a tendency for a northeast landslide orientation. that corresponds to the general orientation of the slopes inclined to the petrinjčica river valley that is the lowest in the area. in contrast, to the southwest side of the pliocene unit, the utinja stream flows which is approximately 55 m higher. consequently, the northeastern slopes have much higher relief energy than the southwestern slopes. surprisingly, the aspect of all 5 x 5 m cells does not follow that trend. north and south aspects are prevalent over east and west orientations. since the aspect disregards the angle of the slope, their orientation was also analyzed by projecting plane poles on a stereographic plot (fig. 11). the main vector was calculated for all slopes and slopes within landslides. in the case of all slopes, this has confirmed the relatively even slope distribution, with only a slight tendency towards the north – northeast. in the case of landslides, the mean pole vector indicates the northeast plane aspect, although not as clear as in fig. 10. besides relief energy, the prevailing factor indicating the northeast landslide orientation could be due to the geological setting. the pliocene unit tends to dip towards the northeast which could favour that direction for landslides. this is confirmed by only a small number of measured bedding planes as the area is covered, so there are only a few outcrops, and even then, bedding planes are not always visible. however, the whole regional setting of the pliocene unit indicates the northeast aspect. quantifying the influence of relief energy and bedding plane orientation is difficult, but they are the most probable culprits for uneven landslide distribution in the pliocene unit. 5.3. landslide susceptibility factors and scale landslide susceptibility can be used for different purposes and at different scales, and therefore many methods and factors have been developed for determining it (cascini, 2008; fell et al., 2008; reichenbach et al., 2018; saleem et al., 2019; zhou et al., 2016). despite all this effort, there is no universally accepted standard method for any scale or purpose. this study does not attempt to resolve this, as the study area is too insignificant in size or factor variability. despite that, some conclusions can be made that may serve as guidance in a future attempt at standard method development, at least in the region where this study was conducted. the results of this study imply a scale of 1:100.000 as the largest scale for a more simplistic approach. there is a basic geological map available at that scale for the whole country of croatia. as stated before, chronostratigraphic units used in that map are a problem, but would be acceptable in most cases. however, that should be tested for each case. gus are one of the most important factors, as seen with the help of the landslide index (fig. 7). the example of the dpr gu reminds us of a need for caution as there can be problems related to this data. maps in that scale, or smaller, can be compiled in less time and with fewer financial resources. susceptibility maps at larger scales can lead to significant misconceptions if a more detailed approach is not undertaken. examples from three gus in this study demonstrate this. the pliocene, miocene, and palaeocene-eocene gus have very contrasting areas within them regarding landslide densities. when the landslides are averaged over the whole area of the corresponding gu, each gu can be assessed in landslide susceptibility with enough precision for scales of 1:100.000 or smaller. in contrast, the same approach at larger scales would introduce a lot of inaccuracies. furthermore, every gu had unique factors that caused drastically different landslide susceptibilities. considering the modest area of this study and such heterogeneity, it is hard to hypothesize a universal method for determining landslide susceptibility at large scales, which would apply to large regions with a lot more gus. this implies that scales larger than 1:100.000 require much more extensive data. in the region of this study, that involves extensive fieldwork as such data is not readily available remotely. 6. conclusion a landslide inventory was created for an area of 22.6 km2 near petrinja city. lidar scanning and orthophoto maps were used for producing the inventory. a total of 216 landslides were detected, which cover 0.66 square km or 2.91 % of the total area. lidar data proved an exceptional data source as it provides high precision and accuracy of the ground surface, even in forested areas. the most notable difficulties concerning creating the landslide inventory presented in this study are subjectivity in demarcating the landslide outlines and the unknown times of landslide activation. grading landslides based on the discernibility of their features in the lidar and orthophoto data may indicate a relative landslide age, but it is too ambiguous for reliable conclusions to be drawn. the geology of the study area was described based on a basic geological map of sfry at a scale of 1:100.000. on that foundation 11 gus were identified in the area. only three gus had more than ten landslide bodies within them, so a more detailed analysis was conducted on them. the vast majority of landslides were discovered in the pliocene gu with 182 landslides or 84%. it is followed by the badenian unit with 16 landslides and the palaeocene-eocene unit with 13 landslides. those numbers were normalized based on the total surface area of each gu and were g eo lo gi a c ro at ic a geologia croatica 75/148 expressed as a landslide index. the pliocene gu has the largest landslide susceptibility with a landslide index of 6.7. it is followed by the palaeocene-eocene unit with 4.2 and finally the badenian unit with 0.9. the average landslide index for the whole area was 2.9. the holocene diluvial-proluvial unit (dpr) has a large landslide index of 1.4, but that is based on only one large landslide situated on the border with the pliocene gu, so it is dismissed as unreliable for further conclusions. slope angle in landslide bo dies also confirms the pliocene gu as the most susceptible, followed by the palaeocene-eocene unit and finally the badenian unit. other gus present in the area should not be regarded as not susceptible to landslides, based only on this study. their represented surface area and/or other risk factors are low (slope, local relief). that excludes them from any reliable conclusions on landslide susceptibility in other regions. only holocene alluvial sediments (a, a1, ap) could be regarded as not landslide susceptible as they are found only in flat areas. an exception to that rule would be landslides along the river banks that are not present in the study area. all three investigated gus have an uneven distribution of landslides in their respective areas. in all three cases, the determining factors are different. in the case of the pliocene gu, there is an indication that the dominant factors for larger landslide susceptibility are higher local relief and unfavourable bedding plane orientation on affected slopes. different lithologies is the reason in the palaeocene-eocene gu, with conglomerates having very low susceptibility and sandstones, siltstones, and sandy marls having much larger susceptibility. human impact in the form of a road is the most probable factor in the badeninan gu, but it cannot be proven without the known activation times of the landslides. if the scale of 1:100.000 is considered, basic geological maps of sfry are a good enough source for geological data input for landslide susceptibility maps, but with certain limitations. in the case of lithologically heterogeneous gus, a more detailed approach is needed. for more detailed scales, basic geological maps of sfry are not adequate by themselves. based on the results of this study, landslide susceptibility maps at scales larger than 1:100.000 demand more individual approaches in determining the most influencing factors. acknowledgment the lidar dataset was a crucial component in this research. it was acquired within the safearth project, co-financed by the interreg ipa cross-border cooperation programme croatia bosnia and herzegovina montenegro 2014-2020. references aleotti, p., & chowdhury, r. (1999): landslide hazard assessment: summary review and new perspectives.– bulletin of engineering geology and the environment, 58/1, 21–44). doi: 10.1007/s100640050066 allaby, m. (2020): a dictionary of geology and earth sciences.– oxford university press, 720 p. available online on https://doi.org/10.1093/ acref/9780198839033.001.0001 [accesed on 11.07.2021.]. allmendinger, r. w., cardozo, n., & fisher, d. m. (2012): structural geology algorithms: vectors and tensors.– cambridge university press, 289 p. doi: 10.1017/cbo9780511920202 anbalagan, r. (1992): landslide hazard evaluation and zonation mapping in mountainous terrain.– engineering geology, 32/4, 269–277. doi: 10.1016/00137952(92)90053-2 bartelletti, c., giannecchini, r., d’amato avanzi, g., galanti, y., & mazzali, a. (2017): the influence of geological-morphological and land use settings on shallow landslides in the pogliaschina t. basin (northern apennines, italy).– journal of maps, 13/2, 142–152. doi: 10.1080/17445647.2017.1279082 bell, r., petschko, h., röhrs, m., & dix, a. (2012): assessment of landslide age, landslide persistence and human impact using airborne laser scanning digital terrain models.– geografiska annaler, series a: physical geography, 94/1, 135– 156. doi: 10.1111/j.1468-0459.2012.00454.x booth, a. m., roering, j. j., & perron, j. t. (2009): automated landslide mapping using spectral analysis and high-resolution topographic data: puget sound lowlands, washington, and portland hills, oregon.– geomorphology, 109/3–4, 132–147. doi: 10.1016/j.geomorph.2009.02.027 bucci, f., santangelo, m., cardinali, m., fiorucci, f., & guzzetti, f. (2016): landslide distribution and size in response to quaternary fault activity: the peloritani range, ne sicily, italy.– earth surface processes and landforms, 41/5, 711–720. doi: 10.1002/esp.3898 cardozo, n., & allmendinger, r. w. (2013): spherical projections with osxstereonet.– computers and geosciences, 51, 193–205. doi: 10.1016/j. cageo.2012.07.021 carrara, a., cardinali, m., detti, r., guzzetti, f., pasqui, v., & reichenbach, p. (1991): gis techniques and statistical models in evaluating landslide hazard.– earth surface processes and landforms, 16/5, 427–445. doi: 10.1002/esp.3290160505 cascini, l. (2008): applicability of landslide susceptibility and hazard zoning at different scales.– engineering geology, 102/3–4, 164–177. doi: 10.1016/j. enggeo.2008.03.016 conforti, m., & ietto, f. (2020): influence of tectonics and morphometric features on the landslide distribution: a case study from the mesima basin (calabria, south italy).– journal of earth science, 31/2, 393–409. doi: 10.1007/ s12583-019-1231-z cred, unisdr (2018): economic losses, poverty & disasters 1998-2017. available online at: https://www.preventionweb.net/files/61119_credeconomiclosses.pdf [accesed on 13.07.2021.]. cruden, d. m., & varnes, d. j. (1996): landslide types and processes.– special report, national research council, transportation research board, 247, 36–75. čubrilović, p., palavestrić, l., nikolić, t., & ćirić, b. (1967): inženjerskogeološka karta sfr jugoslavije 1:500000 [engineering geological map of sfr of yugoslavia 1:500000 – in croatian].– savezni geološki zavod, beograd. della seta, m., del monte, m., fredi, p., & lupia palmieri, e. (2004): quantitative morphotectonic analysis as a tool for detecting deformation patterns in soft-rock terrains: a case study from the southern marches, italy.– géomorphologie : relief, processus, environnement, 10/4, 267–284. doi: 10.3406/morfo.2004.1224 european environment agency. (2010): mapping the impacts of natural hazards and technological accidents in europe.– european environment agency, 144 p , 13. doi: 10.2800/62638 fell, r., corominas, j., bonnard, c., cascini, l., leroi, e., & savage, w. z. (2008): guidelines for landslide susceptibility, hazard and risk zoning for land use planning.– engineering geology, 102/3–4, 85–98. doi: 10.1016/j. enggeo.2008.03.022 getachew, n., & meten, m. (2021): weights of evidence modeling for landslide susceptibility mapping of kabi-gebro locality, gundomeskel area, central ethiopia.– geoenvironmental disasters, 8, 6. doi: 10.1186/s40677-021-00177-z gökceoglu, c., & aksoy, h. (1996): landslide susceptibility mapping of the slopes in the residual soils of the mengen region (turkey) by deterministic stability analyses and image processing techniques.– engineering geology, 44/1–4, 147–161. doi: 10.1016/s0013-7952(97)81260-4 görüm, t. (2019): landslide recognition and mapping in a mixed forest environment from airborne lidar data.– engineering geology, 258, 105155. doi: 10.1016/j. enggeo.2019.105155 guzzetti, f., cardinali, m., reichenbach, p., & carrara, a. (2000): comparing landslide maps: a case study in the upper tiber river basin, central italy.– environmental management, 25/3, 247–263. doi: 10.1007/s002679910020 guzzetti, fausto, carrara, a., cardinali, m., & reichenbach, p. (1999): landslide hazard evaluation: a review of current techniques and their application in a multi-scale study, central italy.– geomorphology, 31/1–4, 181–216. doi: 10.1016/s0169-555x(99)00078-1 guzzetti, fausto, mondini, a. c., cardinali, m., fiorucci, f., santangelo, m., & chang, k. t. (2012): landslide inventory maps: new tools for an old problem.– earth-science reviews, 112/1–2, 42–66. doi: 10.1016/j.earscirev.2012.02.001 haque, u., blum, p., da silva, p.f., andersen, p., pilz, j., chalov, s.r., malet, j.-p., auflič, m.j., andres, n., poyiadji, e., lamas, p.c., zhang, w., peshevski, i., pétursson, t.k., dobrev, n., garcíadavalillo, j.c., halkia, m., ferri, s., gaprindashvili, g., engström, j. & keellings, d. (2016): fatal landslides in europe.– landslides, 13/6, 1545–1554. doi: 10.1007/s10346-016-0689-3. hervás, j., & bobrowsky, p. (2009): mapping: inventories, susceptibility, hazard and risk.– in: landslides disaster risk reduction.– springer, berlin, heidelberg, 321–349. doi: 10.1007/978-3-540-69970-5_19 g eologia c roatica frangen et al.: use of a lidar-derived landslide inventory map in assessing influencing factors for landslide susceptibility of geological units ... 49 horváth, f., musitz, b., balázs, a., végh, a., uhrin, a., nádor, a., koroknai, b., pap, n., tóth, t., & wórum, g. (2015): evolution of the pannonian basin and its geothermal resources.– geothermics, 53, 328–352. doi: 10.1016/j.geothermics.2014.07.009 jaboyedoff, m., oppikofer, t., abellán, a., derron, m. h., loye, a., metzger, r., & pedrazzini, a. (2012): use of lidar in landslide investigations: a review.– natural hazards, 61/1, 5–28. doi: 10.1007/s11069-0109634-2 jurak, v., matkovi, i., miklin, ž., & cvijanović, d. (1998): landslide hazard in the medvednica submountain area under dynamic conditions.– in: marić, b., lisac, z. & szavits-nossan, a. (eds.): geotechnical hazards, xith danube european conference on soil mechanics and geotechnical engineering.– taylor & francis, 827–834. doi: 10.1201/9781003078173-114 kamb, w. b. (1959): ice petrofabric observations from blue glacier, washington, in relation to theory and experiment.– journal of geophysical research, 64/11, 1891– 1909. doi: 10.1029/jz064i011p01891 klose, m., maurischat, p., & damm, b. (2015): landslide impacts in germany: a historical and socioeconomic perspective.– landslides, 13/1, 183–199. doi: 10.1007/s10346-015-0643-9 kurečić, t. (2017): sedimentologija i paleoekologija pliocenskih viviparus slojeva vukomeričkih gorica [sedimentology and paleoecology of pliocene viviparus beds from the area of vukomeričke gorice – in croatian].– unpubl. phd thesis, faculty of science, university of zagreb, 168 p. kurečić, t., kovačić, m., & grizelj, a. (2021): mineral assemblage and provenance of the pliocene viviparus beds from the area of vukomeričke gorice (central croatia).– geologia croatica, 74/3, 253-271. doi: 10.4154/gc.2021.16 malamud, b. d., turcotte, d. l., guzzetti, f., & reichenbach, p. (2004): landslide inventories and their statistical properties.– earth surface processes and landforms, 29/6, 687–711. doi: 10.1002/esp.1064 mallet, c., & bretar, f. (2009): full-waveform topographic lidar: state-of-theart.– isprs journal of photogrammetry and remote sensing, 64/1, 1–16. doi: 10.1016/j.isprsjprs.2008.09.007 mandic, o., kurečić, t., neubauer, t. a., & harzhauser, m. (2015): stratigraphic and palaeogeographic significance of lacustrine molluscs from the pliocene viviparus beds in central croatia.– geologia croatica, 68/3, 179–207. doi: 10.4154/gc.2015.15 markušić, s., stanko, d., penava, d., ivančić, i., bjelotomić oršulić, o., korbar, t., & sarhosis, v. (2021): destructive m6.2 petrinja earthquake (croatia) in 2020–preliminary multidisciplinary research.– remote sensing, 13/6, 1095. doi: 10.3390/rs13061095 mccalpin, j. (1984): preliminary age classification of landslides for inventory mapping.– proceedings of the annual symposium on engineering geology and soil engineering, 21, moscow, idaho, 99–120. molin, p., fubelli, g., & dramis, f. (2012): evidence of tectonic influence on drainage evolution in an uplifting area: the case of northern sila (calabria, italy).– geografia fisica e dinamica quaternaria, 35/1, 49–60. doi: 10.4461/ gfdq.2012.35.5 neumayr, m., & paul, c. m. (1875): die congerienund paludinenschichten slavoniens und deren faunen : ein beitrag zur descendenz-theorie / von m. neumayr und c.m. paul.– hölder, 164 p. doi: 10.5962/bhl.title.14331 pavelić, d., & kovačić, m. (2018): sedimentology and stratigraphy of the neogene rift-type north croatian basin (pannonian basin system, croatia): a review.– marine and petroleum geology, 91, 455–469. doi: 10.1016/j.marpetgeo.2018.01.026 pawluszek, k. (2019): landslide features identification and morphology investigation using high-resolution dem derivatives.– natural hazards, 96/1, 311–330. doi: 10.1007/s11069-018-3543-1 petschko, h., bell, r., & glade, t. (2016): effectiveness of visually analyzing lidar dtm derivatives for earth and debris slide inventory mapping for statistical susceptibility modeling.– landslides, 13/5, 857–872. doi: 10.1007/s10346-0150622-1 pikija, m. (1983): geološka i strukturna obrada područja petrinja-hrastovica-slana.– unpubl. report, geološki zavod, zagreb, 26 p. pikija, m. (1987a): osnovna geološka karta sfrj 1:100000, list sisak l33−93 [basic geological map of sfry 1:100000, sisak sheet l33-93 – in croatian].– geološki zavod, zagreb, savezni geološki institut, beograd. pikija, m. (1987b): osnovna geološka karta sfrj 1:100.000, tumač za list sisak l33–93 [basic geological map of sfry 1:100000, geology of the sisak sheet l33-93 – in croatian].– geološki zavod, zagreb, savezni geološki institut, beograd. pollak, d., gulam, v., novosel, t., avanić, r., tomljenović, b., hećej, n., terzić, j., stipčević, j., bačić, m., kurečić, t., dolić, m., bostjančić, i., wacha, l., kosović, i., budić, m., vukovski, m., belić, n., špelić, m., brčić, v., barbača,j., kordić, b., palenik, d., filjak, r., frangen, t., pavić, m., urumović, k., sečanj, m., matoš, b., govorčin, m., kovačević, m.s. & librić, l. (2021): the preliminary inventory of coseismic ground failures related to december 2020 – january 2021 petrinja earthquake series.– geologia croatica, 74/2, 189–208. doi: 10.4154/gc.2021.08 razak, k. a., straatsma, m. w., van westen, c. j., malet, j. p., & de jong, s. m. (2011): airborne laser scanning of forested landslides characterization: terrain model quality and visualization.– geomorphology, 126/1–2, 186–200. doi: 10.1016/j.geomorph.2010.11.003 reichenbach, p., rossi, m., malamud, b. d., mihir, m., & guzzetti, f. (2018): a review of statistically-based landslide susceptibility models.– earthscience reviews, 180, 60–91. doi: 10.1016/j.earscirev.2018.03.001 rundić, l., vasić, n., životić, d., bechtel, a., knežević, s., & cvetkov, v. (2016): the pliocene paludina lake of pannonian basin: new evidence from northern serbia.– annales societatis geologorum poloniae, 86/2, 185–209. doi: 10.14241/asgp.2016.003 saftić, b., velić, j., sztanó, o., juhász, g., & ivković, ž. (2003): tertiary subsurface facies, source rocks and hydrocarbon reservoirs in the sw part of the pannonian basin (northern croatia and south-western hungary).– geologia croatica, 56/1, 101–122. doi:10.4154/232 saleem, n., enamul huq, m., twumasi, n. y. d., javed, a., & sajjad, a. (2019): parameters derived from and/or used with digital elevation models (dems) for landslide susceptibility mapping and landslide risk assessment: a review.– isprs international journal of geo-information, 8/12, 545. doi: 10.3390/ ijgi8120545 schulz, w. h. (2007): landslide susceptibility revealed by lidar imagery and historical records, seattle, washington.– engineering geology, 89/1–2, 67–87. doi: 10.1016/j.enggeo.2006.09.019 schulz, w.h. (2004): landslides mapped using lidar imagery, seattle, washington.u.s.– geological survey open–file report 2004–1396, 11 p. šestanović, s. (2001): osnove geologije i petrografije [fundamentals of geology and petrography – in croatian].– sveučilište u splitu, građevinski fakultet, 234 p. slatton, k. c., carter, w. e., shrestha, r. l., & dietrich, w. (2007): airborne laser swath mapping: achieving the resolution and accuracy required for geosurficial research.– geophysical research letters, 34/23, 1–5. doi: 10.1029/2007gl031939 tobler, w. (1987): measuring spatial resolution.– in: proceedings of the land resources information systems conference, beijing, china, 25–29 october 1987, pp. 12–16. van den eeckhaut, m., & hervás, j. (2012): state of the art of national landslide databases in europe and their potential for assessing landslide susceptibility, hazard and risk.– geomorphology, 139–140, 545–558. doi: 10.1016/j.geomorph.2011.12.006 van westen, c. j., castellanos, e., & kuriakose, s. l. (2008): spatial data for landslide susceptibility, hazard, and vulnerability assessment: an overview.– engineering geology, 102/3–4, 112–131. doi: 10.1016/j.enggeo.2008.03.010 wieczorek, g. f. (1983): preparing a detailed landslide-inventory map for hazard evaluation and reduction.– bulletin of the association of engineering geologists, 21/3, 337–342. doi: 10.2113/gseegeosci.xxi.3.337 zaninović, k., gajić-čapka, m., perčec tadić, m., vučetić, m., milković, j., bajić, a., cindrić, k., cvitan, l., katušin, z., kaučić, d., likso, t., lončar, e., lončar, ž., mihajlović, d., pandžić, k., patarčić, m., srnec, l. & vučetić, v. (2008): klimatski atlas hrvatske: 1961-1990, 1971-2000 [climate atlas of croatia: 1961-1990, 1971-2000 – in croatian].– državni hidrometeorološki zavod, zagreb, 200 p. zhou, s., chen, g., fang, l., & nie, y. (2016): gis-based integration of subjective and objective weighting methods for regional landslides susceptibility mapping.– sustainability, 8/4, 334. doi: 10.3390/su8040334 2018 | 71/1 | 19–28 | 8 figs. | 3 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction gypsum is by far the most abundant secondary mineral in sedimentary settings, sometimes forming the calcium sulfate mineral anhydrite in arid and hot supratidal environments (sabkhas) in the presence of concentrated brines, but rarely at the surface (kins man, 1966; butler, 1969; shearman, 1985; stroh menger et al., 2008; zaki et al., 2011; abrantes et al., 2016). gypsum is readily prone to dehydration, producing water and anhydrite, when heated to a temperature that is high enough as a function of the salinity of coexisting fluids (hardie, 1967; azimi et al., 2011; ma et al., 2015). thus, the most common process that causes the dehydration of gypsum, and thus the formation of anhydrite, is burial to depths below the reaction isotherm, in settings where fluids can still escape the system. if anhydrite is uplifted back above the reaction isotherm, it can return to gypsum, provided sufficient water is available. ancient evaporites are economically important sources of salts (e.g., gypsum) and metals (e.g., cu, zn, and au), as well as being key indicators for the existence of structural oil and gas traps (warren, 2006). upper permian evaporite deposits occur in the dinarides in central dalmatia (tišljar, 1992) and can be observed at a number of sites. three known sites in this region that contain evaporite deposits were formerly active quarries for the extraction of gypsum and are thus the focus of this study: the mali kukor a mineralogical and petrographic study of evaporites from the mali kukor, vranjkovići, and slane stine deposits (upper permian, dalmatia, croatia) željko dedić*, nikolina ilijanić and slobodan miko croatian geological survey, sachsova 2, p.o. box 268, hr-10000 zagreb, croatia (*corresponding author: zdedic@hgi-cgs.hr) doi: 10.4154/gc.2018.02 abstract the evaporite deposits examined in this study are located in the central part of middle dalmatia, croatia. in this region, upper permian evaporite sediments were deposited under favourable conditions onto the variscan basement around the northern margins of gondwana. these sediments can be subdivided into three members, a lower evaporite unit (an anhydrite member), a middle evaporite unit (a gypsum member), and an upper unit (a clastic member), and are mainly comprised of secondary gypsum that formed via the hydration of precursor anhydrite rocks. the middle evaporite unit comprises beds of gypsum as well as early diagenetic dolomites that contain gypsum sequences, extending up to 60 m maximum thickness, and overlying clastic sequences that themselves are up to 20 m thick. these upper permian evaporite sediments contain horizontal, irregular, gypsum lithofacies that exhibit pronounced enterolithic and boudinage structures. the characteristics of these sediments are indicative of deposition in supratidal and sabkha settings (i.e., early diagenetic dolomites and evaporites) within a shallow epicontinental marine environment with highly varied coastlines, bays, and lagoons. the secondary gypsum seen within this upper permian middle evaporite unit displays alabastrine and porphyroblastic secondary textures and includes corroded anhydrite relics; associated minerals include muscovite, chlorite, potassium (k)-feldspar, quartz, and amphibole. the upper permian evaporite sediments discussed in this study are composed of irregular, locally brecciated secondary gypsum that probably formed as a result of multiple synsedimentary collapse of pre-existing soluble minerals and/or synsedimentary and post-sedimentary tectonics. quarry in kosovo polje, vranjkovići quarry near vrlika, and the slane stine quarry near sinj. the aim of this study is to highlight the depositional environments and phases of diagenetic evolution that led to the formation of these upper permian evaporites based on the results of petrographic and sedimentological investigations of beds within the sequences at these sites. the upper permian evaporites and adjacent sediments known from middle dalmatia have been the subject of extensive geological investigations in the past (tišljar, 1992, šušnjara et al., 1992, gabrić et al., 2002). previous studies have addressed the age of these sequences, their superposition and tectonic relationships with surrounding rocks, their mineralogy, petrology, and chemical composition, and have determined the conditions and environments of their deposition. the most comprehensive resource available regarding the geology of this area is the basic geological maps of the republic of croatia at a 1:100,000 scale, specifically the knin, drniš, and sinj sheets (grimani et al., 1962–1966; papeš et al., 1962– 1966; grimani et al., 1975; ivanović et al., 1977; ivanović et al., 1978; raić et al., 1984). these deposits have also been extensively studied in order to calculate the extent of gypsum reserves as a mineral commodity; this research has generated detailed site data based on exploration drilling and core analyses (lukšić et al., 2005). the upper permian evaporites and adjacent sediments known from middle dalmatia were deposited above a variscan basement in hypersaline marine and/or marine-marginal deposiarticle history: manuscript received august 09, 2017 revised manuscript accepted december 20, 2017 available online february 28, 2018 keywords: upper permian, evaporite sediments, gypsum, anhydrite, dalmatia g eo lo gi a c ro at ic a geologia croatica 71/120 tional settings around the margins of northern gondwana (tišljar, 1992). the upper part of the middle permian as well as the upper permian in this region is characterized by the formation of carbonates, notably dolostones and some sabkha evaporites (vlahović et al., 2005). evaporitic rocks within deposits at the kosovo polje were previously studied by kulušić & borojević šoštarić (2014) and considered to be part of the dinaric evaporite mélange. the aim of this study is to highlight the origins of upper permian evaporite depositional environments and to discuss their diagenetic evolution based on petrographic and sedimentological investigations of carbonates and evaporites at a series of study sites. 2. geological setting the study area and deposits discussed in this paper are located in middle dalmatia, croatia (fig. 1), within the central part of the outer dinarides. the dinarides generally encompass a stratigraphic range between the middle permian (or even the upper carboniferous) and the eocene (tišljar et al., 1992; velić et al., 2002a; vlahović et al., 2005). it is thought that deposits ranging from the top of the lower jurassic (toarcian) to the top of the cretaceous can be attributed to the adriatic carbonate platform (adcp), one of the largest mesozoic structures of this type within the peri-mediterranean region (dercourt et al., 1993, 2000; vlahović et al., 2005). figure 1. map to show the locations of the study sites in middle dalmatia, croatia. the reference source for upper permian sediments used in this paper is the 1:300.000 geological map of the republic of croatia (cgs, 2009). g eologia c roatica dedić et al.: a mineralogical and petrographic study of evaporites from the mali kukor, vranjkovići, and slane stine deposits ... 21 the basement of the adcp can be subdivided into several major sequences, the oldest of which encompass upper carboniferous to middle permian rocks and comprise part of the variscan basement. siliciclastic deposition prevailed during the carboniferous period followed by mixed clastic-carbonate deposits in the lower permian and a transition within the lower/middle permian into continental clastic deposition. similarly, the middle permian to middle triassic sequence in this region is characterized by carbonate and mixed siliciclastic-carbonate deposits that formed an epeiric platform at this time along the northern margin of gondwana, while the upper part of the middle permian and upper permian is characterized by carbonates and sabkha evaporites (vlahović et al., 2005). ancient epeiric evaporitic platforms (shaw, 1964; irwin, 1965; wetzel et al., 2013; orti et al., 2017) are huge areas of restricted stagnant circulation on the continental margins of seaways where extensive evaporite beds periodically accumulated (warren, 2006). the upper permian sequences of middle dalmatia comprise three main facies types, carbonates (mainly limestones), evaporites (gypsum and anhydrite), and early diagenetic dolomites and clastics including siltstones, sandstones, and rare conglomerates. exceptional facies types in this region include porous carbonate cavity breccias, so-called “rauchwackes” (šušnjara et al., 1992; tišljar, 1992). 3. methods a series of detailed field investigations of upper permian evaporite units were carried out at the mali kukor, vranjkovići, and slane stine sites (fig. 1). a total of 45 representative samples were selected from processed profiles and subjected to further laboratory analysis; thin sections for mineralogical-petrographic analysis were prepared from all samples, and 24 bulk evaporite samples were selected for x-ray diffraction (xrd) analysis. preparation of evaporite thin sections required the use of a special method. samples were first crushed and hand ground with a pestle and mortar before a few grams of each were sieved through a 125 mesh section. cutting, polishing, and thinning were then carried out using norland optical adhesive 61, glue that hardens under ultraviolet light. all of the thin sections were then examined using a polarizing microscope. bulk sample mineral compositions were determined using a panalytical x’pert powder x-ray diffractometer equipped with ni-filter cu kα radiation, a vertical goniometer with θ/θ geometry, and a pixcel detector. scans were performed at 45 kv and 40 ma using both a ¼ divergence slit and anti-scatter slits and with a step size of 0.002° 2θ every four seconds across a range between 4° 2θ and 66° 2θ. individual minerals were identified on the basis of their reflections following the method outlined by moore & reynolds (1997); semi-quantitative mineral analysis was performed using the software rockjock (eberl, 2003), and the weight percent (wt %) of minerals in each sample was calculated using integrated x-ray intensities. 4. results and discussion 4.1. the lithofacies at mali kukor, vranjkovići, and slane stine detailed field observations enabled the identification of three distinct lithofacies within the quarries, evaporites, carbonates and clastics i.e., siltstones, sandstones and carbonate cavity breccias. the dominant lithofacies in the slane stine quarry comprise anhydrite in the lower part of the profile with clasts that range in size between 1 – 5 cm diameter. this basal sequence is around 25 m thick and occurs beneath an alternating sequence of anhydrite, dolomite, and massive gypsum that marks the middle of the plateau. this overall sequence is then capped by an approximately 15 m thick tectonic zone that comprises green and reddish clastic sediments. the lithofacies within the slane stine quarry also includes fragments of carbonate rocks (dolomites) within evaporative (gypsum) sediments that are characterized by enterolithic folding (fig. 2). the lithofacies in the vranjkovići quarry include poorly developed horizontal laminations of secondary gypsum with dolomite intercalations that contain organic matter in their lower portions. these can be up to 15 m thick and underlie an alternat ing sequence of massive gypsum units including thinly bedded early diagenetic dolomite (ca. 5 m thick) below palaeokarst forms (fig. 3). the lithofacies in the mali kukor quarry comprise dolomites and alternating thinly bedded white and gray gypsum units that contain portions of dolomitic breccia in their lower parts. these units are up to 20 m thick, occurring below a zone of alternating figure 2. (a) fragments of carbonate rocks (dolomites) within evaporitic (gypsum) sediments in the slane stine near sinj. (b) an example of enterolithic folding within the slane stine deposit. a b g eo lo gi a c ro at ic a geologia croatica 71/122 secondary gypsum and anhydrite, which terminates in green and reddish clastic deposits (fig. 4). in summary, the following basic lithofacies are seen at all three sites: • a laminated evaporite-carbonate facies composed of millimetre-centimetre-sized gypsum and anhydrite laminae intercalated with dolomite and dolomicrite and organic matter patches. this facies type is also characterized by horizontal, wavy, and irregular laminations as well as enterolithic, massive, and boudinage-style lithologies; • an evaporite-carbonate breccia facies that is composed of millimet-metre-sized fragments of dolomite and anhydrite relics. the laminated evaporite-carbonate facies also presents a series of very thin evaporite beds and laminae interbedded, or interlaminated, with thinner, dark, lime, muddy structures that contain organic material (possibly algal mats) and thinly bedded dolomites. these evaporite laminae range in thickness from 0.1 mm upwards and often disintegrate into fine-grained dolomicrite and dolomite, organic matter, or anhydrite. evaporite laminae within the sections studied in this paper also display enterolithic and boudinage features forms of dolomite or organic matter patches intercalated with evaporite laminae. evaporite-carbonate breccia facies containing fragments of dolomite or anhydrite relics are seen at all three sites; this lithofacies type consists of angular or irregular fragments of various sizes set within a sulfate groundmass. 4.2. a mineralogical and petrographic evaluation of the evaporites a microscopic mineralogical-petrographic study was carried out on the laminated evaporite-carbonate facies described above that comprises millimetre-to-centimetre scale gypsum and anhydrite laminae intercalated with dolomites, dolomicrites, and organic matter. the results of this investigation show that the upper permian evaporite units from all three sites discussed in this paper are primarily composed of microcrystalline secondary gypsum. samples from all three deposits nevertheless display a variety of textures ranging from xenotopic to idiotopic and encompass four types of secondary gypsum: figure 3. (a) images from the top of the geological profile at vranjkovići showing the alternation between massive gypsum and thinly bedded early diagenetic dolomite that terminates in palaeokarst structures. (b) the lower part of the geological profile at vranjkovići showing poorly developed horizontal laminations of secondary gypsum and dolomite intercalations. figure 4. the lower zone of the geological profile at mali kukor showing alternating thinly bedded white and gray gypsum and organic patches that possibly represent algal mats (a). the upper zone of the geological profile at mali kukor showing organic patches and anhydrite embedded within a gypsum mass (b). a b a b g eologia c roatica dedić et al.: a mineralogical and petrographic study of evaporites from the mali kukor, vranjkovići, and slane stine deposits ... 23 figure 5. thin-section images of sample mk-12, an alabastrine secondary gypsum that contains euhedral-to-subeuhedral features around 200 μm in size. most of the oriented crystals within this sample are relics of fine-grained crystallized secondary dolomite (dol) as well as coarse-grained crystallized secondary dolomite (dol). the image on the left (a) is under plane-polarized light while the one on the right (b) is under cross-polarized light). (1) alabastrine; (2) porphyroblastic; (3) fibrous satin spar, and (4) granoblastic. within these varieties, fibrous satin spar gypsum is the only type formed from sulfate-rich solutions that develop due to anhydrite hydration; all the other varieties form via the rehydration of an anhydrite precursor. the mineral abbreviations used in the subsequent text and figures are as outlined by kretz (1983). observations show that secondary gypsum is the most widespread form seen in upper permian evaporite units at the three sites. this kind of gypsum can be classified into several forms which can be loosely grouped into three stages that comprise a continuous recrystallization sequence. thus, in stage 1, alabastrine secondary gypsum directly forms from anhydrite, contains abundant corroded inclusions, and comprises a mosaic of complex, interlocking anhedral grains that about one another to such an extent that their grain boundaries are almost impossible to trace. viewed under crossed poplars, each grain appears fibrous and ill-defined and exhibits an irregular undulating extinction. the bulk of this type of gypsum appears to have been formed at, or very near, the surface as it develops via the weathering of anhydrite outcrops. when no anhydrite relics are present in stage 1 gypsum, recrystallization is initiated to form stage 2 or stage 3 granoblastic gypsum. this form is not seen adjacent to anhydrite as it does not form from this starting point. stage 2 gypsum comprises small, usually anhedral, grains that are characterized by non-undulatory extinction, sometimes with curved re-entrant boundaries. the grain size of this form is usually uniform, with diameters around 50 μm, and the presence of larger subhedral and euhedral crystals are indicative of further recrystallization to stage 3. thus, stage 3 gypsum, which develops from either stage 2 forms or directly from stage 1, is composed of subhedral or euhedral grains about 100 μm in diameter. it is noteworthy that the grain size of this form can be variable, reaching up to 0.5 mm in diameter; many larger grains can be blasts that contain no anhydrite relics, and have well-developed crystal faces and textures that formed subsequent to the finer gypsum matrix (holliday, 1970). figure 6. thin-section images of sample mk-16, a porphyroblastic secondary gypsum that contains inclusions of carbonates, dolomites, and calcite (cal), as well as corroded anhydrite relics (anh). the image on the left (a) is under plane-polarized light while the one on the right (b) is under cross-polarized light. a b a b g eo lo gi a c ro at ic a geologia croatica 71/124 microscopic thin sections reveal that the textures of alabastrine gypsum can exhibit erratic and migrating extinction shadows when samples are rotated under cross-polarized light (fig. 5). examples of this gypsum with euhedral-to-subeuhedral features comprises the most frequent crystal orientations within the samples examined in this study alongside relics of fine-grained crystallized secondary dolomite (fig. 5). indeed, as these secondary gypsum crystals were most probably formed from anhydrite they can vary from place to place. in early work, ogniben (1957) discussed super-individual examples of alabastrine secondary gypsum that comprise sub-crystals with shadowy grain boundaries as well as the extinction polarization of aggregates of microcrystalline gypsum less than 70 μm in diameter. the crystal size of samples from the mali kukor site (sample mk-12) is around 200 μm, and alabastrine gypsum can include a wide range of related textures which all form a natural grouping, in contrast to the porphyroblastic variety. the crystals of alabastrine gypsum are therefore commonly circular, irregular, or form elongated patches adjacent to, or within, the porphyroblastic form. the boundaries between the finer-grained alabastrine form and its coarser counterpart also tend to exhibit gradational interpenetrating contacts indicative of the replacement of larger gypsum crystals by smaller ones. this process of degradation has been described in miocene evaporites from the red sea (aref, 2003), from messinian evaporites in italy (testa & lugli, 2000), and in pedogenic gypsum crusts (watson, 1988; aref, 2003). in contrast, porphyroblastic gypsum tends to forms both large and small crystals that have generally interlocking margins. in some examples the individual crystals are clearly defined, while in other cases samples can be very coarsely crystalline (fig. 6). porphyroblastic gypsum therefore comprises large, anhedral porphyroblasts up to 1 cm in length that tend to occur as single crystals, although aggregates can also be locally abundant. this form also contains numerous inclusions of corroded anhydrite relics or other associated minerals, and porphyroblasts are surrounded by later alabastrine secondary gypsum, often the stage 3 granoblastic form. other associated minerals can include anhydrite, dolomite, muscovite, chlorite, amphibole, potassium (k)-feldspar, apatite, rutile, and quartz, while pyrite and organic material are also common in some samples. hydration veins are also common features of these secondary lithofacies and are often filled with satin spar gypsum (fig. 7). observations show that gypsum porphyroblasts do not form to any great extent in present-day anhydrite settings where the alabastrine type is dominant, indicating that these structures are components of an earlier phase of gypsification. this conclusion is corroborated by the fact that similar porphyroblasts have been recorded as comprising the earlier form of secondary gypsum in many areas (forbes, 1958; ham, 1962; west, 1964). this kind of gypsum is composed of large euhedral-to-subhedral crystals that exhibit sharp extinction and occur as individual elements or in groups of two or three crystals. holliday (1970) and taj (2012) noted that the origin of porphyroblastic gypsum via anhydrite rehydration was evidenced by corroded anhydrite relics in samples from the three sites they investigated (fig. 6). the fibrous (satin spar) gypsum variety is the only type that forms from sulfate-rich solutions, developed due to the rehydration of anhydrite; all other known types of secondary gypsum form via the rehydration of precursor anhydrite (maklouf et al., 2006). the formation of satin spar gypsum is therefore thought to be the result of the increase in volume that characterizes the transformation of anhydrite to gypsum (shearman et al., 1972; yeşi̇lova & helvaci, 2013). thus, prismatic anhydrite laths are often observed as pseudomorphs within host sediment; for example, fibrous (satin spar) gypsum occurs as veins interbedded within evaporites and within the carbonates of the abu ruweis formation (maklouf et al., 2006). similarly, veins from sample mk-5c (fig. 7) are composed of elongate crystals arranged perpendicular to walls; in this case, veins of fibrous (satin spar) gypsum are interbedded within a dolomite intraclast and comprise an evaporite facies mineral assemblage in thin section. fibrous (satin spar) gypsum is composed of crystals greater than 200 μm in length, while relic anhydrite components greater than 10 μm in size also float within subhedral gypsum crystals that can also sometimes be arranged randomly. it is therefore thought that such randomly oriented crystal veins were originally formed from anhydrite at depth and at high temperatures and pressures, before subsequently being rehydrated to gypsum. a number of previous authors have considered satin spar gypsum to therefore be a by-product of anhydrite rehydration (shearman et al., 1972; testa & lugli, 2000). granoblastic gypsum has a limited distribution within the upper permian evaporite units discussed in this study, recorded in only the mali kukor and vranjkovići deposits. this form exfigure 7. thin-section images of sample mk-5c, gypsum veins within a dolomite intraclast (dol) and a mineral assemblage from the evaporite facies. these images show an anhydrite (anh) relic floating within subhedral crystals of gypsum (gp). the image on the left (a) is under plane-polarized light while the one on the right (b) is under cross-polarized light. a b g eologia c roatica dedić et al.: a mineralogical and petrographic study of evaporites from the mali kukor, vranjkovići, and slane stine deposits ... 25 hibits well-defined euhedral-to-subhedral crystals that have sharp and homogenous extinction patterns. such crystals are almost equigranular in size, range between 10 μm and 50 μm, interlock with one another, and form mosaic textures. these granular crystals also exhibit dominantly euhedral faces toward porphyroblastic gypsum, indicative of a replacement origin, and this secondary type is also characterized by the absence of anhydrite relics. it is therefore thought that granoblastic gypsum represents an advanced stage of anhydrite rehydration (west, 1964, 1965; holliday, 1970; warren, 1999, maklouf & elhaddad, 2006, taj, 2012). on the basis of the petrographic descriptions presented in this study, it is clear that the upper permian gypsum evaporites from selected sites across middle dalmatia are mainly composed of secondary gypsum that most probably originated from either the hydration (by groundwater) of and/or the surface weathering of precursor anhydrite rocks. it is noteworthy in this context that the term “secondary gypsum” was first used by murray (1964) and then later by holliday (1970) and shearman (1972) to refer to gypsum that formed via hydration of anhydrite. 4.3. the bulk mineralogy of evaporite samples the results of bulk xrd analysis of 24 samples (tabs. 1–3) shows that the dominant mineral components are gypsum, dolomite, and anhydrite, while calcite, chlorite, k-feldspar, muscovite, quartz, amphibole, and apatite also occur in smaller proportions. celestine and rutile were detected in just one sample from the mali kukor site (sample mk-8). mineral compositions at the slane stine site are dominated by gypsum, anhydrite, and muscovite, with the exception of samples ss-12a and ss-pir which do not contain anhydrite (tab. 1). dolomite is also present in most cases in minor concentrations, but is the dominant phase (alongside gypsum) in sample ss-pir, while apatite, rutile, and quartz also occur in minor amounts. gypsum is the dominant mineral phase in all samples from the mali kukor site (tab. 2; fig. 8), while anhydrite was seen in just one sample (mk-anh) from this site, and calcite is present in samples mk-3, mk-8, and mk-14. mineral phases that appear in minor concentrations in the samples from this site include amphibole, quartz, and muscovite (in samples mk-14 and mk-16), while dolomite is only seen in sample mk-16, celestine is only observed in sample mk-8, and hydroxylapatite is only seen in samples mk-3 and mk-5b. all the samples from the vranjkovići site contain both gypsum and dolomite as their main mineral phases (tab. 3), while minor amounts of amphibole are also present in nearly all samples (with the exception of vr-6), alongside muscovite in samples vr-11, vr-12, vr-13, and vr-14, k-feldspar in samples vr-5-2, vr-11, vr-12, vr-13, and vr-14, apatite in samples vr-5-1 and vr-5b, and anhydrite in sample vr-11. the microscopic and xrd investigations of upper permian evaporite samples discussed here reveal the presence of carbonates table 1. bulk semi-quantitative mineralogy of evaporite samples from the slane stine site. sample gypsum anhydrite dolomite muscovite chlorite amphibole k-feldspar apatite rutile quartz ss-2 83 7 1 8 – 1 – ss-3a 86 4 2 8 – – – – – – ss-6a 76 5 3 12 3 – – – 1 – ss-12a 63 – 3 14 7 1 9 – 3 ss-pir 30 – 60 7 – 3 – – – – table 2. bulk semi-quantitative mineralogy of evaporite samples from the mali kukor site. sample gypsum calcite dolomite amphibole quartz muscovite celestine apatite anhydrite mk-3 15 83 – – 1 – – 1 – mk-5b 97 – – 2 – – – 1 – mk-8 80 12 – 2 3 – 3 – – mk-12 97 – – 2 1 – – – – mk-14 88 5 – 2 1 4 – – – mk-16 88 – 3 2 – 7 – – – mk-anh 67 – – 2 – – – – 31 table 3. bulk semi-quantitative mineralogy of evaporite samples from the vranjkovići site. sample gypsum dolomite amphibole apatite k-feldspar muscovite anhydrite vr-5-1 87 11 1 1 – – – vr-5-2 68 25 1 – 6 – – vr-5b 79 19 1 1 – – – vr-6 97 3 – – – – – vr-6b 97 1 2 – – – – vr-9a 99 – 1 – – – – vr-11 90 – 1 – 3 5 1 vr-12 79 6 1 – 7 7 – vr-13 69 22 2 – 4 3 – vr-14 66 23 2 – 4 5 – vr-15 94 4 2 – – – – vr-18 50 50 – – – – g eo lo gi a c ro at ic a geologia croatica 71/126 in addition to gypsum. the data show that dolomite is dominant at the vranjkovići and slane stine sites, while calcite is most abundant at the mali kukor site. calcite occurs as regular crystals at the mali kukor site (fig. 4; e.g., sample mk-16) alongside a mass of secondary gypsum that generally exhibits both alabastrine and porphyroblastic textures associated with corroded anhydrite relics. it is thought that this kind of gypsum forms via the replacement of carbonate minerals (i.e., dolomite and calcite) with sulfate-rich solutions. the textural characteristics of this gypsum indicate that carbonate minerals (i.e., calcite or dolomite) were originally replaced by anhydrite, which was in turn replaced by secondary gypsum. indeed, as this is likely to have been the case, the replacement of carbonate minerals took place at depth under both high temperature and pressure, and favored the formation of anhydrite rather than gypsum (murray, 1964; holliday, 1970; kendall, 1989; testa & lugli, 2000, amadi et al., 2010). the fact that gypsum occurs locally as lenticular crystals scattered amongst dolomite (fig. 5) probably indicates that it directly replaced carbonate minerals under near-surface conditions (warren, 1999). the alternation of gypsum and dolomite as couplets continues upwards through the sections studied here and suggests a “dolomite-gypsum rhythmical pattern” at different levels within outcrop successions. observations show that each couplet comprises a dark-gray, thin-to-thickly bedded dolomite overlain by thickly bedded white gypsum; rhythmic couplets are distinct, but irregularly spaced, and are rich in organic matter when they occur, transitioning upwards into nodular gypsum (fig. 2). 4.4. interpretation of different gypsum types experimental studies and modern sedimentary analogues indicate that primary gypsum is more commonly precipitated under normal surface conditions (hardie, 1967; shearman, 1985; testa & lugli, 2000, schreiber & helman, 2005). this means that the anhydrite precursor to this process can be interpreted as a diagenetic product derived from the dehydration of primary gypsum (murray, 1964; holliday, 1970, kasprzyk, 2003); thus, primary gypsum is transformed diagenetically into anhydrite either during burial (murray, 1964; holliday, 1970; testa & lugli, 2000; kirkland, 2003), or via solar heating as was the case for miocene evaporites in the northwestern red sea (aref et al., 2003). tišljar (1992) concluded, for example, that evaporitic conditions around the edges of epeiric marine basins tend to exist when general regressive conditions are in place, associated with ongoing coastal seaward progradation. the microscopic investigations reported here indicate that most of the observed types of secondary gypsum associated with the evaporite units studied resulted from the hydration of precursor anhydrite. the data suggest that all of the types of gypsum seen in evaporite units within the study area (e.g., alabastrine secondary gypsum, porphyroblastic gypsum, fibrous satin spar, and granoblastic gypsum) are of secondary origin, and this observation is confirmed by the widespread presence of satin spar gypsum veins within upper permian units. the veins have been considered by many authors to be the result of anhydrite hydration (holliday, 1970; kendall, 1989; testa & lugli, 2000). it is therefore thought to be the case that these upper permfigure 8. upper permian evaporite sample xrd patterns from the mali kukor site (i.e., samples mk-3, mk-8, and mk-anh). abbreviations: gp, gypsum; cal, calcite; anh, anhydrite. g eologia c roatica dedić et al.: a mineralogical and petrographic study of evaporites from the mali kukor, vranjkovići, and slane stine deposits ... 27 ian evaporite units were originally deposited as gypsum anhydrite? (see below) under restricted shallow marine saline conditions, although this may have varied over time. additional evidence for this conclusion comes from their regular bedding and the fact that they are interbedded with marine carbonates. during uplift, the exposed parts of these upper permian anhydrites were modified to gypsum, although remaining similar to other subsurface examples (andrews, 1992; dalqamuni, 1995). 5. conclusion the mineralogical and petrographic evaluations of evaporitic sediment thin sections presented in this study reveals the characteristics of evaporitic rocks, indicating their primary diagenetic products, and enables a determination of the changes seen throughout the geological evolution of such sediments. the evaporitic sediments investigated in this study are mainly secondary gypsums that also contain dolomite, anhydrite, muscovite, calcite, quartz, amphibole, and clay minerals. secondary gypsum can occur in various structural types that range from idiotopic to xenotopic, of which alabastrine, porphyroblastic, and granoblastic types are recognized here alongside a fourth fibrous satin spar structure seen in one sample. alabastrine and porphyroblastic types most probably correspond to the upper phreatic groundwater zones, while the appearance of gypsum on, or near to, the surface, as well as the presence of anhydrite in deeper parts, reflects the fact that secondary gypsum minerals are the result of anhydrite hydration. this hydration process is initiated at the edges of anhydrite crystal cleavage planes in the form of fibrous satin spar gypsum, especially in tectonically disturbed and cracked zones. the microscopic and xrd investigations reported in this study reveal that the upper permian evaporites at all three sites are primarily composed of microcrystalline secondary gypsum. indeed, the evaporites at the vranjkovići and mali kukor sites predominantly comprise gypsum with very little anhydrite, while gypsum and anhydrite are present in equal quantities at slane stine. microscopic investigations indicate that most of the gypsum microfacies within these upper permian evaporites are the result of parent anhydrite hydration. the analyses presented in this study also confirm the presence of dolomite and calcite as carbonate minerals. the results of xrd analyses show that dolomite is also present, alongside gypsum and/or anhydrite, at both the vranjkovići and slane stine sites, while calcite dominates at mali kukor. the main conclusion of this study is that the total mineralogical composition of the investigated evaporitic sediments is indicative of several stages of deposition, and that there are key differences between samples from slane stine and vranjkovići and mali kukor. the main rock constituent at all sites is gypsum intercalated with dolomite, with the exception of mali kukor where a calcite component dominates the lower part of the section. the upper permian evaporite units investigated in this study are mainly composed of microcrystalline secondary gypsum. acknowledgement this study was supported by the ministry of science and education of the republic of croatia scientific project: the map of mineral resources of the republic of croatia. the authors also wish to thank all those who contributed to the successful completion of this research, especially erli kovačević galović from the croatian geological survey, zagreb, for their assistance, useful comments, and suggestions on this paper. references abrantes jr, f.r., nogueira, a.c.r. & soares j.l. (2016): permian paleogeography of west-central pangea: reconstruction using sabkha-type gypsum-bearing deposits of parnaíba basin, northern brazil.– sedimentary geology, 341, 175–188. andrews, i. (1992): permian, triassic and jurassic lithostratigraphy in the subsurface of jordan: natural resources authority of jordan.– subsurface geol. div., bull. 4. amadi, f.o., major, r.p. & baria, l.r. (2010): origin of gypsum in deep carbonate rock; primary gypsum vs. rehydrated anhydrite.– geological society of america, 42, p.138. aref, m., a.m., abu el–enain, f.m. & abdallah, g. (2003): origin of secondary gypsum of the miocene abu dabbab evaporites, nw red sea coast, egypt.– fifth international conference on the geology of the middle east, 321–330. butler, g.p. (1973): strontium geochemistry of modern and ancient calcium sulphate minerals.– in: purser, b.h. (ed.): the persian gulf. holocene carbonate sedimentation and diagenesis in a shallow epicontinental sea. springer, 423–452. croatian geological survey (2009): geološka karta republike hrvatske 1:300.000, izrađena na temelju osnovne geološke karte m 1:100.000, područje republike hrvatske [geological map of the republic of croatia 1:300 000 – in croatian].– zagreb. dalqamuni, a. (1995): sequence stratigraphy and petroleum prospects of the upper triassic sediments (abu ruweis), north jordan.– unpublished msc thesis, yarmouk university, jordan. dercourt, j., ricou, l.e. & vrienlinck, b. (1993): atlas tethys – palaeoenvironmental maps. gauthier-villars, paris. dercourt, j., geatani, m., vrielinck, b., barrier, e., biju-duval, b., brunet, m.-f., cadet, j.-p., crasquin, s. & sandulescu, m. (ed.), (2000): atlas peri-tethys: palaeogeographical maps. ccgm/cgmw, paris, 24 maps and explanatory notes: xx + 269 pp. eberl, d.d. (2003): user guide to rockjock – a program for determining quantitative mineralogy from x-ray diffraction data.– us geol. surc. open file rep., 03–78. forbes, b.g. (1958): folded permian gypsum of ripon parks, yorkshire. proc. yorks. geol. soc., 31, 351–358. gabrić, a., šinkovec, b., sakač, k. & kuljak, g. (2002): ležišta gipsa u republici hrvatskoj.– rudarsko-geološko-naftni zbornik, 14, 21–36. grimani, i., šikić, k. & šimunić, a. (1962–1966): osnovna geološka karta sfrj 1:100000, list knin l33−141 [basic geological map of sfry 1:100000, knin sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. grimani, i., juriša, m., šikić, k. & šimunić, an. (1975): tumač osnovne geološke karte sfrj, l: 100 000, list knin, (l-33-141) [basic geological map of sfry 1:100000, geology of the knin sheet – in croatian, english abstract].– inst. geol. istraž. zagreb, savez. geol. zavod beograd, 1–61. ham, w.e. (1962): economic geology and petrology of gypsum-anhydrite cap rock, sulphur salt dome, louisiana.– mem. geol. soc. am., 50. hardie, l.a. (1967): the gypsum-anhydrite equilibrium at one atmosphere pressure.– am. min., 52, 171–200. holliday, d.w. (1970): the petrology of secondary gypsum rocks: a review.– j. sediment. petrol., 40, 734–744. irwin, m.l. (1965): general theory of epeiric clear water sedimentation.– american association of petroleum geologist bulletin, 49, 445–459. ivanović, a., sikirica, v., marković, s. & sakač, k. (1977): osnovna geološka karta sfrj 1:100000, list drniš [basic geological map of sfry 1:100000, drniš sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. ivanović, a., sikirica, v. & sakać, k. (1978): tumač osnovne geološke karte sfrj, l : 100 000, list drniš, (k 33-9) [basic geological map of sfry 1:100000, geology of the drniš sheet – in croatian, english abstract].– inst geol. istraž. zagreb, savez. geol. zavod, beograd. kasprzyk, a. (2003): sedimentological and diagenetic patterns of anhydrite deposits in the badenian evaporite basin of the carpathian foredeep, southern poland.– sedimentary geology, 158, 167–194. kendall, a.c. (1989): brine mixing in the devonian of western canada and its possible significance to regional dolomitization.– sediment. geol., 64, 271–285. kinsman, d.l. (1966): gypsum and anhydrite of recent age, trucial coast, persian gulf.– second symposium on salt, northern ohio geol. soc. cleveland, 1, 302–326. kirkland, d.w. (2003): an explanation for the varves of the castile evaporites (upper permian), texas and newmexico,usa.– sedimentology, 50, 898–920. kretz, r. (1983): symbols of rock-forming minerals.– american mineralogist, 68, 277–279. g eo lo gi a c ro at ic a geologia croatica 71/128 kulušić, a. & borojević šoštarić, s. (2014): dinaride evaporite mélange: diagenesis of the kosovo polje evaporates.– geologia croatica, 67/1, 59–74. doi: 10.4154/gc.2014.05 lukšić, b., crnogaj, s., dedić, ž. & jurić, a., (2005): report on gypsum reserves of the novo bulatovo and pusto groblje quarries of the kosovo exploitation field.– unpublished report, croatian geological survey, zagreb. ma, b., cao, y., eriksson, k.a., jia, y. & wang, y. (2016): burial evolution of evaporites with implications for sublacustrine fan reservoir quality: a case study from the eocene es4x interval, dongying depression, bohai bay basin, china.– marine and petroleum geology, 76, 98–114. maklouf, i.a. & el-haddad, a.a. (2006): depositional environments and facies of the late triassic abu ruweis formation, jordan.– journal of asian earth sciences, 28, 372–384. moore, d.m. & reynolds, r.c. (1997): x-ray diffraction and the identification and analysis of clay minerals.– oxford univ. press, oxford, 378 p. murray, r.c. (1964): origin and diagenesis of gypsum and anhydrite.– journal of sedimentary petrology, 34, 512–523. orti, f., perez-lopez, a. & salany, j.m. (2017): triassic evaporites of iberia; sedimentological and palaeogeographical implications for the western neotethys evolution during the middle triassic-earliest jurassic.– palaeogeography, palaeoclimatology, palaeoecology, 471, 157–180. ogniben, l. (1957): secondary gypsum of the sulphur series, sicily, and the so-called integration.– journal of sedimentary petrology, 27, 64–79. papeš, j., marinkovič, r., raić, v., magaš, n. & sikirica, v. (1968–1980): osnovna geološka karta sfrj 1:100000, list sinj k 33−10 [basic geological map of sfry 1:100000, sinj sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. raić, v., papeš, j., sikirica, v. & magaš, n. (1984): tumač osnovne geološke karte sfrj, 1:100000, list sinj (k 33-10). [basic geological map of sfry 1:100000, geology of the sinj sheet – in croatian, english abstract].– geoinženjering, institut za geologiju sarajevo, geološki zavod, oour za geologiju i paleontologiju. izd. savez. geol. zavod, beograd, l–52. schreiber, b.c. & helman, m.l. (2005): criteria for distinguishing primary evaporite features from deformation features in sulfate evaporites.– journal of sedimentary research, 75, 525–533. shaw, a.b. (1964): time in stratigraphy: new york – mcgraw-hill, 365 p. shearman, d.j. (1985): syndepositional and later diagenetic alteration of primary gypsum to anhydrite.– the sixth symposium salt, the salt institute, vol. 1, 44–55. shearman, d.j., mossop, g.d., dunsmore, h. & martin, m. (1972). origin of gypsum veins by hydraulic fracture.– institute of mining and metallurgy transactions (section b), 81, 149–155. strohmenger, c.j., al-mansoori, a., al-jeelani, o., al-hosani, i., alshamry, a., shebl, h., al-mehsin, k. & al-baker, s. (2008): the arid shallow subtidal to supratidal environment; a case study from the abu dhabi sabkha (united arab emirates). abstracts: annual meeting – american association of petroleum geologists, 2008. šušnjara, a., sakač, k., jelen, b. & gabrić, a. (1992): upper permian evaporites and associated rocks of dalmatia and borderline area of lika and bosnia.– geologia croatica, 45, 95–114. taj, r.j.a. (2012): lower miocene coastal lagoon carbonates and evaporites of rabigh area, red sea coast, saudi arabia. journal of king abdulaziz university: marine sciences, 23, 131–164. testa, g. & lugli, s. (2000): gypsum anhydrite transformation in messinian evaporites of central tuscany (italy).– sediment. geol., 249–268. tišljar, j. (1992): origin and depositional environments of the evaporitic and carbonate complex (upper permian) from the central part of the dinarides (southern croatia and westen bosnia).– geologia croatica, 45, 115–126. tišljar, j., vlahović, i., velić, j. & sokač, b. (1992): carbonate platform megafacies of the jurassic and cretaceous deposits of the karst dinarides.– geologia croatica, 55, 139–170. velić, i., vlahović, i. & matičec, d. (2002): depositional sequences and paleogeography of the adriatic carbonate platform.– mem. soc. geol. ital., 57, 141–151. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: paleogeography, main events and depositional dynamics.− palaeogeography, palaeoclimatology, palaeoecology, 220, 333–360. doi: 10.1016/j.palaeo.2005.01.011 warren, j. (1999): evaporites: their evolution and economics.– blackwell science, oxford, uk, 438 p. warren, j.k. (2006): evaporites: sediments, resources and hydrocarbons.– isbn 3-540-26011-0 springer berlin heidelberg new york, p. 1041. watson, a. (1988): desert gypsum curst as paleoenviroment indicators: micropetrographic study from southern tunisia and the central namib desert.– j. arid environ., 15, 19–42. west, i.m. (1964): evaporite diagenesis in the lower purbeck beds of dorset.– geol. soc. yorkshire proc., 34, 315–330. west, i.m. (1965): macrocell structure and enterlolithic facies in the visean of ireland.– geol. soc. yorkshire proc., 35, 47–58. wetzel, a., weissert, h., schaub, m., voeglin, a.r. & föllmi, k. (2013): sea-water circulation on an oolite-dominated carbonate system in an epeiric sea (middle jurassic, switzerland).– sedimentology, 60, 19–35. yesilova, p.g. & helvaci, s. (2013): diagenesis and paleogeographic development of oligocene evaporites of the germik formation (kurtalan, sw siirt), turkey.– yerbilimleri, 34, 1–22. zaki, r., wali, a. & mosa, m. (2011): sedimentological and hydrochemical spectrum of recent continental sabkha and signs of its capabilities to generate hydrocarbons: a case study in northwest el fashn area, western desert, egypt.– carbonates & evaporites, 26, 273–286. in memoriam pamic.indd jakob pamić passed away suddenly and unexpectedly on march 5th, 2004. it was a great shock for all of us who had the privilege to be befriended by him, because jakša, as he was known to friends, was active to the last minute, bursting with energy and full of future plans and unfinished projects; his desk was left full of papers, notes, manuscripts and unanswered e-mails. i freely confess, it was very difficult for me to speak coherently at his funeral. even during the last two months or so he was particularly active: he was gathering around himself a group of younger collaborators from the three principal geological institutions in zagreb (which means, in croatia; faculty of science, faculty of mining, geology, and petroleum engineering, and institute of geology) and urged them to write articles; this was intended to be a series of papers published as a special issue of a renowned international geological journal devoted to the dinarides, which jakša succeeded to obtain thanks to his good connections with foreign colleagues. this is not the appropriate place to enumerate one by one jakša’s numerous scientific papers (see bibliography below) nor to review in detail his many and important scientific achievements. they deserve to be reviewed and scrutinized for their own sake, which will be done by forthcoming generations of croatian geologists. there will be no shortage of opportunity for that, as jakša, with his most impressive opus of over 300 published scientific papers, many of them in renowned international journals, fixed an indelible seal on croatian, and not only croatian, geology. let us remember just a few basic facts: jakob pamić was born in požega, slavonia (north croatia) nearly 76 years ago, and in spite of the fact that he travelled extensively and worked both in various regions of the in memoriam former yugoslavia and abroad (iran), he never broke the connections with his native region and was always very fond of returning home. he obtained both his b.sc. and ph.d. in geology at the faculty of science, university of zagreb, and soon after obtaining his b.sc. degree he went to sarajevo, in bosnia and herzegovina, where he remained fully active for 30 years. first he was appointed assistant at sarajevo university, but soon moved to the bosnia and herzegovina institute of geology (in fact, a geological survey) where he served in various posts (chief of department, chief of sector, technical director – i.e. the scientific head) for the rest of his stay in bosnia. what is, in this respect, particularly worth mentioning, is the fact that, during all that time, he permanently and regularly maintained close ties with his home university department, here in zagreb, sending younger colleagues to graduate studies in zagreb, showing them how to do geology and participating, as a member of the examination panel, in their m.sc. and ph.d. theses. thus he greatly influenced bosnian geology, directing it more towards the zagreb geological school. summing up his activity in sarajevo, it can be said that the geology in (and of) bosnia and herzegovina nowadays would be far below its presentday level, regardless of how high we regard that, without jakob pamić and his enthusiastic work. jakša pamić coauthored 11 sheets and corresponding explanatory notes of the basic geological map 1:100,000 of the former yugoslavia, which covered a large part of the sometimes impassable bosnian territory. we geologists are well aware of what it means to be the author or coauthor of 11 sheets of a 100,000 geological map. this refers particularly to the northern part of bosnia, i.e., to the area known among geologists as the inner (or internal) dinarides, characterized by a highly complex geological structure. he devoted par geologia croatica 57/1 103–115 zagreb 2004 dr. sc. jakob pamić 1928–2004 104 geologia croatica 57/1 105in memoriam – dr. sc. jakob pamić ticular attention to the so-called ophiolite zone (which also intrigued mijo kišpatić, the originator and founder of croatian petrography, whom pamić also highly respected), to which he contributed several seminal contributions. his early papers already dealt with this topic, even before the advent of plate tectonics, and pamić assumed the ultramafites originated in the deepest part of the lithosphere or upper mantle, respectively, paying particular attention to the eclogitic-amphibolitic rocks. therefore he was also elected a member of the editorial board of the journal “ofioliti”. more recently, jakša focused his attention on the north-western extension of the vardar zone, i.e., its continuation from the eastern dinarides through north bosnia to northwestern croatia, central slovenia and the contact with the alps. he interpreted it as a continuation of the periadriatic lineament into the contact area between the dinarides and the tisia/moesia. however, he also worked on numerous other geological problems: he studied triassic, late cretaceous, palaeogene, and neogene magmatism of the dinarides, and he was the first in croatia to deal with isotope geochemistry (in collaboration with colleagues from the usa). in short, he was engaged in the investigation of numerous geological, petrological, and geochemical problems of almost all magmatic complexes, both in the dinarides and the pannonian basin, also including the variscan granitic and metamorphic complexes of our so-called insular mountains in slavonia. to all these topics he always used the polythematic (or multidisciplinary) approach. in the meantime, he spent a year (1975/76) as a professor at the international university in shiraz, iran, where he taught petrology and isotope geochemistry. in 1981 he returned to zagreb, as a senior scientist at the institute of geology, and, in addition to that, was invited to lecture, as a part-time professor, in the graduate study of geology at the faculty of science of zagreb university, the course entitled “magmatism and metamorphism of the orogenic belts”. in 1992 jakša was elected a corresponding member of the croatian academy of sciences and arts, though, judging by his scientific achievements, he deserved to be elected a full member. unfortunately, he didn’t live to see that merited recognition. his retirement in 1995 did not weaken his scientific activity, neither in the domestic nor in the international field. therefore it was more than deserved that he became, in 1999, the recipient of the state award for life achievement in natural sciences. this was the only official award he ever received. as previously mentioned, jakša was author of more than 300 scientific papers, which were published in a wide array of international and domestic journals. about 60 of his papers were published in journals referred to in the current contents database. in addition, he was the author or coauthor of a dozen or so monographs, deliberately written in croatian in order to be of maximum use for domestic geologists; for half of these monographs he was sole author. therefore, he was not only the most productive, but also the most widely internationally cited croatian geologist, (as supported by over 160 citations within the last ten years in the quotation index). it is obvious that he was an exceptionally industrious and hard-working person; but he also stimulated other people, i.e. those who knew how to appreciate his enthusiasm and profit from his broad knowledge. i can safely say that i know several younger colleagues whom jakša helped to broaden their geological horizons and to view their particular geological problems seamlessly embedded in a broader, even global, geological framework. i am quite sure that these colleagues would confirm these words, if asked to. some reproached him for writing too much. i myself sometimes criticized him for having written too profusely on a locally or regionally restricted topic. jakša’s answer to such reproach was that geology was the only job he knew how to do; therefore he did it tirelessly and with maximum enthusiasm. many foreign colleagues recognized that and therefore, in addition to being chief investigator or collaborator on a number of domestic projects, he was often invited abroad to participate at various international scientific conferences and symposia, where he delivered a number of notable talks, most of which were subsequently published as papers in peer-reviewed journals. he was chief investigator on five international projects, and a participant in two croatian–usa collaborative projects some ten years ago. by incorporating his own geological perceptions into mainstream global geology, jakša contributed, more than any other croatian geologist of his (and younger) generation, to the recognition of croatian geoscience in international, european and world-wide arenas. it is worth mentioning that as early as 1973, i.e. more than 30 years ago, jakša wrote a review article – the first one to be published in the former yugoslavia – on the factography and application of plate tectonics, and he consistently applied that new, geological paradigm in all his papers, just as he always placed his petrological work into a broader geological setting. being a scientist, jakša did not believe in life after death. nevertheless, we may send him this last message: dear jakša, even if we do not always, and in every detail agree with some of your geological perceptions, and even if we do not always and without reservation accept all of your geological interpretations, this is how it should be in geology, as well as in any other true science. however, you have erected to yourself an everlasting monument in both croatian, and worldwide geology. we who had the privilege to be your friends during your life shall remember you forever, and your name and your opus will be the model and stimulus for generations of geologists to come. may you rest in peace in this earth as you so enthusiastically studied all your life! ivan gušić 104 geologia croatica 57/1 105in memoriam – dr. sc. jakob pamić bibliography of jakob pamić papers published in journals covered by isi pamić, j. (1971): some petrological features of the bosnian gabbroperidotite complexes in the dinaride zone of yugoslavia.– tschermak’s miner.-petrogr. mitteil., 15, 14–42, wien. pamić, j., šćavničar, s. & međimorec, s. (1973): mineral assemblages of amphibolites associated with alpine-type ultramafics in the dinaride ophiolite zone (yugoslavia).– journ. petrology, 14/1, 133–157, oxford. pamić, j. (1974): alpine-type gabbros within the krivaja– konjuh ultramafic massif in the ophiolite zone of the dinarides, yugoslavia.– tschermak’s miner.-petrogr. mitteil., 21, 261–279, wien. pamić, j. (1975): plagioclase peridotite – a cumulus differentiate from gabbro magma, and the alpine lherzolite– pyrolite relations within the dinaride central ophiolite zone.– petrologie, 1/4, 335–342, nancy. lanphere, m., coleman, r., karamata, s. & pamić, j. (1975): age of amphibolites associated with alpine peridotites in the dinaride ophiolite zone, yugoslavia.– earth and plan. sci. lett., 26, 271–276, amsterdam. pamić, j. (1977): the amphibole–peridotite–gabbro complex finero, northern italy: discussion.– journ. geology, 85, 494–497, chicago. pamić, j. (1977): variation in geothermometry and geobarometry of the peridotite intrusions in the dinaride central ophiolite zone, yugoslavia.– amer. mineralogist, 62/ 9–10, 874–886, washington, d.c. pamić, j. & majer, v. (1977): ultramafic rocks of the dinaride central ophiolite zone in yugoslavia.– journ. geology, 85, 553–569, chicago. pamić, j., sestini, g. & adib, d. (1979): alpine magmatic and metamorphic processes and plate tectonics in the zagros range, iran.– bull. geol. soc. amer., 90, 569–576, washington, d.c. karamata, s., majer, v. & pamić, j. (1980): the ophiolites of yugoslavia.– in: rocci, g. (ed.) “tethyan ophiolites”, ofioliti, 1, 170–189, firenze. pamić, j. & adib, d. (1980): interpretation comme rodingites des skarns decrits dans le massif ultramafique de neyriz (zagros sud-oriental, iran).– compt. r. acad. scie. de la france, 291, 363–366, paris. pamić, j. (1982): correlation between mesozoic spilite– keratophyre associations of the continental and oceanic crust origin as exemplified by the dinarides.– earth evol. scie., 2/1, 36–40, berlin. pamić, j. (1982): some geological problems of the dinaride ophiolites and their associations.– earth evol. scie., 2/1, 30–35, berlin. pamić, j. & adib, d. (1982): high-grade amphibolites and granulites at the base of the neyriz peridotites in southerneastern iran.– neues jahrb. mineral., abh., 143, 113–121, stuttgart. pamić, j. (1983): consideration on the boundary between lherzolite and harzburgite subprovinces in the dinarides and hellenides.– ofioliti, 8/1, 153–164, firenze. lanphere, m. & pamić, j. (1983): 40ar/39ar ages and tectonic setting of ophiolites from the neyriz area, southeast zagros range, iran.– tectonophysics, 96, 245–256, amsterdam. pamić, j. (1984): triassic magmatism of the dinarides in yugoslavia.– tectonophysics, 109, 273–307, amsterdam. karamata, s., majer, v. & pamić, j. (1988): mafic and ultramafic rock associations – indicators of tectonic setting.– geol. carpathica, 39/5, 599–604, bratislava. pamić, j. (1989): hercynian and alpine granitic–metamorphic complexes of the adjoining area of the dinarides and pannonian basin in yugoslavia as related to geodynamics.– geol. carpathica, 40/3, 259–280, bratislava. pamić, j. & desmons, j. (1989): a complete ophiolite sequence in rzav area of zlatibor and varda ultramafic massifs, the dinaride ophiolite zone.– ofioliti, 14, 13–32, firenze. pamić, j. & lanphere, m. (1992): alpine a-type granites from the collisional area of the northernmost dinarides and pannonian basin, yugoslavia.– neues jahrb. mineral., abh., 162, 215–236, stuttgart. pamić, j. (1993): eoalpine to neoalpine magmatic and metamorphic processes in the northwestern vardar zone, the easternmost periadriatic zone and the southwestern pannonian basin.– tectonophysics, 226, 503–518, amsterdam. pamić, j., mckee, e.h., bullen, t.d. & lanphere, m.a. (1995): tertiary volcanic rocks from the southern pannonian basin, croatia.– intern. geological review, 37, 259–283, stanford, usa. pamić, j., lanphere, m.a. & belak, m. (1996): hercynian i-type and s-type granitoids from the slavonian mountains (southern pannonian basin, croatia).– neues jahrb. mineral. abh., 171, 155–186, stuttgart. pamić, j., gušić, i. & jelaska, v. (1998): geodynamic evolution of the central dinarides.– tectonophysics, 297, 251–268, amsterdam. tari-kovačić, v. & pamić, j. (1998): geodynamic evolution of the northern dinarides and south pannonian basin.– tectonophysics, 297, 269–281, amsterdam. pamić, j. (1998): north dinaridic late cretaceous–paleogene subduction-related tectonostratigraphic units of south tisia, croatia.– geologica carpathica, 49, 341–350, bratislava. haas, j., mioč, p., pamić, j., tomljenović, b., árkai, p., berczi-makk, a., kovács, s., ralisch-felgenhauer, e. & koroknai, b. (1999): continuation of the periadriatic lineament, alpine and nw dinaridic units in the pannonian basin.– geologica carpathica, 50, 150–151, bratislava. márton, e., pavelić, d., tomljenović, b., pamić, j. & márton, p. (1999): first paleomagnetic results on tertiary rocks from the slavonian mountains in the southern pannonian basin, croatia.– geologica carpathica, 50, 273–279, bratislava. pamić, j., belak, m., bullen, t.d., lanphere, m.a. & mckee, e.h. (2000): geochemistry and geodynamics 106 geologia croatica 57/1 107in memoriam – dr. sc. jakob pamić of a late cretaceous bimodal volcanic association from the southern part of the pannonian basin in slavonija (northern croatia).– mineralogy and petrology, 68, 271– 296, vienna. pamić, j. & palinkaš, l. (2000): petrology and geochemistry of paleogene tonalites from the easternmost periadriatic zone.– mineralogy and petrology, 76, 121–141, vienna. haas, j., mioč, p., pamić, j., tomljenović, b., árkai, p., bérczi-makk, a., koroknai, b., kovács, s. & felgenhauer, e.r. (2000): complex structural pattern of the alpine–dinaridic–pannonian triple junction.– int. j. earth sci., 89, 377–389, berlin. pamić, j., péskay, z. & balen, d. (2000): k–ar ages of tertiary shoshonite and high-k calc-alkaline volcanic rocks from north dinarides in bosnia.– mineralogy and petrology, 70, 313–320, vienna. pamić, j. & balen, d. (2001): petrology and geochemistry of egerian–eggenburgian and badenian tholeiite– calc-alkaline volcanics from the south pannonian basin (croatia).– neues jahrb. mineralogie, abh., 176, 237– 267, stuttgart. pamić, j. & jurković, i. (2002): paleozoic tectonostratigraphic units in the northwest and central dinarides and the adjoining south tisia.– intern. j. earth sci., 91, 538–554, berlin. pamić, j., balen, d. & tibljaš, d. (2002): petrology and geochemistry of orthoamphibolites from the variscan metamorphic sequences of the south tisia in croatia: an overview.– intern. j. earth sci., 91, 787–797, berlin. pamić, j., tomljenović, b. & balen, d. (2002): geodynamic and petrogenetic evolution of alpine ophiolites from the central and northwest dinarides: an overview.– lithos, 65, 113–142, amsterdam. pamić, j., balen, d. & herak, m. (2002): origin and geodynamic evolution of late paleogene magmatic associations along the periadriatic–sava–vardar magmatic belt.– geodinamica acta, 15, 209–231, paris. slovenec, d. & pamić, j. (2002): geology of the vardar zone ophiolites of mt. medvednica located along the zagreb–zemplin line, nw croatia.– geologica carpathica, 53/1, 53–59, bratislava. pamić, j. (2002): the sava–vardar zone of the dinarides and hellenides versus the vardar ocean.– eclog. geol. helv., 95, 99–113, bern. márton, e., pavelić, d., tomljenović, b., avanić, r. & pamić, j. (2002): in the wake of a counter-clockwise rotation of adriatic microplate: neogene paleomagnetic results from northern croatia.– int. j. earth sci., 91, 514–523, berlin. mioč, p. & pamić, j. (2002): the continuation of the internal dinaridic units in the transitional area between the easternmost periadriatic line and the northernmost southern alps in slovenija.– geologica carpathica, 53, 138–141, bratislava. operta, m., pamić, j., balen, d. & tropper, p. (2003): corundum-bearing amphibolites from the metamorphic basement of the krivaja–konjuh ultramafic massif (dinaride ophiolite zone, bosnia).– mineralogy and petrology, 77, 287–295, vienna. pamić, j. & lanphere, m. (2003): ar–ar ages of paleozoic crystalline rocks from the slavonian mts. in south tisia (croatia).– american mineralogist, in press, washington, d.c. papers published in journals with international review pamić, j. & karamata, s. (1971): k probleme ofiolitov v dinaridah.– izvestja akad. nauk sssr, ser. geologič., 4, 139–142, moskva. adib, d. & pamić, j. (1980): rodingites from the southeastern parts of the neyriz ophiolite complex in the zagros range, iran.– arch. scie. 33/2–3, 281–290, geneve. pamić, j. (1983): permo–triassic rift faulting and magmatism of the dinarides.– ann. soc. geol. france, tc iii, 133–141, lille. pamić, j. (1986): magmatic and metamorphic complexes of the adjoining area of the northernmost dinarides and pannonian mass.– acta geol. hungarica, 29/3–4, 203– 220, budapest. pamić, j. & pikija, m. (1987): badenian andesites and pyroclastics from baranja in northern croatia (yugoslavia).– acta geol. hungarica, 30/1–2, 111–132, budapest. pamić, j. (1988): ultramafics from metamorphic complexes of the slavonian mountains (northern croatia, yugoslavia).– newsletter, 7, 221–227, padova. šimunić, a. & pamić, j. (1993): geology and petrology of egerian–eggenburgian andesites from the easternmost parts of the periadriatic zone in hrvatsko zagorje (croatia).– acta geologica hungarica, 36, 315–330, budapest. jerinić, g., pamić, j., sremac, j. & španić, d. (1994): palynological and first organic-petrographic data on very lowand low-grade metamorphic rocks in the slavonian mountains (northern croatia).– geol. croatica, 47, 149–155, zagreb. pamić, j. (1997): the northwesternmost outcrops of the dinaridic ophiolites: a case study of mt. kalnik.– acta geol. hungarica, 40, 37–56, budapest. pamić, j. (1998): the development of croatian geoscience as reflected by the study of dinaridic ophiolites.– geologia croatica, 50/2, 173–180, zagreb. pamić, j. & tomljenović, b. (1998): basic geological data on the croatian part of the mid-transdanubian zone as exemplified by mt. medvednica located along the zagreb–zemplin fault zone.– acta geol. hungarica, 42, 23–29, budapest. pamić, j., jelaska, v., gušić, i., šikić, k., belak, m. & tomić, v. (1998): tectonostratigraphic units and terranes between the adriatic sea and the southern pannonian basin.– ann. géol. des pays helléniques, 37, 401–427, athéns. balen, d. & pamić, j. (2001): tertiary shoshonite volcanic associations from the adjoining area of the pannonian basin and dinarides.– acta vulcanologica, 13/1–2, 117–125, pisa–roma. pamić, j. & balen, d. (2001): tertiary magmatism of the dinarides and the adjoining south pannonian basin.– acta vulcanologica, 13/1–2, 9–24, pisa–roma. 106 geologia croatica 57/1 107in memoriam – dr. sc. jakob pamić hamzabegović, a., sijarić, g., pamić, j. & hrvatović, h. (2001): crust of weathering of peridotites from the žepče area, the dinaride ophiolite zone in bosnia.– acta vulcanologica, 13/1–2, 175–180, pisa–roma. palinkaš, l. & pamić, j. (2001): geochemical evolution of oligocene and miocene magmatism along the easternmost periadratic line.– acta vulcanologica, 13/1–2, 41–56, pisa–roma. pamić, j. (2003): the allochthonous fragments of the internal dinarides in the southern part of the pannonian basin.– acta geol. hungarica, 46/1, 41–62, budapest. mioč, p. & pamić, j. (2003): the continuation of the internal dinaridic units in the area between the periadriatic lineament and the southern alps in slovenia.– acta geol. hungarica, 46/1, 29–39, budapest. jurković, i. & pamić, j. (2003): carbon and oxygen isotope composition of the dinaridic ophiolite related magnesites.– in: eliopoulus, d.g. et al. (eds.): mineral exploration and sustainable development, 2, 883–886, millpress, rotterdam. papers published in journals with domestic review pamić, j. (1955): pojave gipsa i anhidrita u gornjim tokovima rijeke rame i doljanke (okolica jablanice i prozora).– geol. glas., 1, 187–197, sarajevo. trubelja, f. & pamić, j. (1956): novi prilog poznavanju dacitskih stijena okolice maglaja.– geol. glas., 2, 56–66, sarajevo. pamić, j. (1957): petrološka studija efuzivnih stijena u oblasti ilidža–kalinovnik; i. područje igmana i si padina bjelašnice.– geol. glas., 3, 171–180, sarajevo. jovanović, r. & pamić, j. (1958): pojave kiselih magmatskih stijena na južnim padinama prenja.– publik. tehn. fak. u sarajevu, 1/1, 59–60, sarajevo. pamić, j. (1959): kontaktnometamorfne pojave u trijaskim sedimentima južno od prozora.– geol. vjesnik, 13, 197– 212, zagreb. pamić, j. (1961): rezultati mikroskopskih i kemijskih ispitivanja granitskih stijena s južnih padina prenja u hercegovini.– geol. glas., 5, 263–269, sarajevo. pamić, j. (1961): spilitsko–keratofirska asocijacija stijena u području jablanice i prozora.– acta geol. jazu, 3, 5–80, zagreb. pamić, j. (1962): petrološka studija efuzivnih stijena u oblasti ilidža–kalinovnik: ii. područje izvorišta rijeke željeznice.– geol. glas., 6, 45–59, sarajevo. pamić, j. & jurić, m. (1962): razvoj trijasa u području južno od jajca.– geol. glas., 6, 107–110, sarajevo. pamić, j. (1963): osvrt na problem mezozojskih vulkanogeno–sedimentnih formacija u dinaridima na području bosne i hercegovine.– geol. glas., 8, 5–27, sarajevo. pamić, j. (1963): trijaski vulkaniti okolice čevljanovića i kratak osvrt na trijaski vulkanizam u zoni borovica– vareš–čevljanovići.– geol. glas., 7, 9–20, sarajevo. behlilović, s. & pamić, j. (1963): ladinska vulkanogena tvorevina u dolini drežanke (hercegovina).– geol. glas., 7, 39–44, sarajevo. pamić, j. & antić, r. (1964): anklave peridotitskih stijena u gabroidnom kompleksu gostovićke rijeke kod zavidovića.– geol. glas., 9, 5–14, sarajevo. pamić, j. & karamata, s. (1964): pojave granitoidnih stijena u srednjoj bosni.– geol. glas., 10, 227–232, sarajevo. pamić, j., dimitrov, p. & zec, f. (1964): geološke karakteristike dacitoandezita u dolini bosne.– geol. glas., 10, 241–250, sarajevo. trubelja, f. & pamić, j. (1965): petrološka studija planine ozren.– acta geologica, 4, 265–314, zagreb. pamić, j. & buzaljko, r. (1966): srednjotrijaski spiliti i keratofiri u okolici čajniča (ji bosna).– geol. glas., 11, 55–78, sarajevo. pamić, j. & maksimović, v. (1967): srednjotrijaski kvarc–albitski dijabazi u skitskim sedimentima bijele kod konjica.– geol. glas., 12, 131–137, sarajevo. pamić, j. & antić, r. (1968): serpentin–vebsterit s magnezijskim spinelom s planine čavke u bosni.– geol. glas., 12, 139–144, sarajevo. pamić, j. & kapeler, i. (1969): gabrodoleritska masa kozaračkog potoka u okolici prijedora.– acta geologica, 6, 27–44, zagreb. pamić, j. & podubsky, v. (1969): vulkanske stijene paleozoika sane i njihov položaj u geološkom stupu.– acta geologica, 6, 45–54, zagreb. pamić, j. & papeš, j. (1969): produkti ladiničkog magmatizma u širem području kupreškog polja (bosna).– geol. an. balk. poluos., 34, 557–576, beograd. pamić, j. & olujić, j. (1969): albitski graniti s gostilja u okolici azbestnog rudnika bosansko petrovo selo.– geol. glas., 13, 199–204, sarajevo. pamić, j. (1970): osnovne petrološke karakteristike kromitskog područja duboštice u bosni.– geol. glas., 14, 135–148, sarajevo. pamić, j. & tojerkauf, e. (1970): pojave granita na obodu borjanskog ultramafitskog masiva.– geol. glas., 14, 149–153, sarajevo. pamić, j. & kapeler, i. (1970): korundski amfiboliti na južnom obodu krivajsko–konjuškog ultramafitskog masiva.– geol. an. balk. poluost., 35, 399–408, beograd. olujić, j., pamić, j. & vuletić, n. (1971): preliminarni podaci o pojavama titana u ofiolitskoj zoni u bosni.– geol. glas., 15, 99–107, sarajevo. pamić, j. (1972): ultramafitsko–amfibolitska masa skatavice u ofiolitskoj zoni dinarida.– glas. zem. muz. u bih, 20, 39–47, sarajevo. pamić, j. (1972): novi prilog poznavanju magmatskih stijena okolice rudog u ji bosni.– geol. glas., 16, 123–132, sarajevo. pamić, j. (1973): faktografija tektonike ploča i neki primjeri njene primjene.– geol. glas., 17, 1–57, sarajevo. pamić, j. & majer, v. (1973): eklogiti i amfiboliti crnog potoka na južnim obodima ultramafitskog masiva planine borje u bosni.– geol. glas., 17, 151–170, sarajevo. 108 geologia croatica 57/1 109in memoriam – dr. sc. jakob pamić pamić, j. & popević, a. (1973): korund–amfibolitski škriljavci u amfibolitima bistrice na južnom obodu zlatiborskog ultramafitskog masiva.– glas. prir. muz. srp. zemlje, a, 28, 31–39, beograd. pamić, j. & olujić, j. (1974): hydrothermal–metasomatic rock (listvenites) from the northern border of the ozren ultramafic massif (yugoslavia).– acta geologica, 7, 239–255, zagreb. ćirić, m. & pamić, j. (1975): reliktna feralitna zemljišta u okolici vlasenice.– acta biol. yugosl., zemlj. i biljaka, 24/1–2, 107–117, beograd. pamić, j. (1975): novi prilog poznavanju jablaničkog gabra u hercegovini.– acta geologica, 8, 233–280, spomenica akademiku luki mariću, zagreb. pamić, j., vujnović, l. & paškvalin, lj. (1976): geološko–petrološke karakteristike srednjotrijaskih vulkanita iz doline rijeke vrbasa u području donji vakuf–jajce.– geol. glas., 21, 77–94, sarajevo. pamić, j. (1976): petrološke karakteristike magmatskih stijena ofiolitskog melanža i senonske vulkanogeno–sedimentne formacije na sz obroncima majevice i ji padinama trebovca u sjevernoj bosni.– glas. zem. muz. u bih, 15, 5–17, sarajevo. pamić, j. & buzaljko, r. (1976): trijaski vulkaniti iz najnižih tokova rijeke pive kod šćepan polja u crnoj gori.– geol. glas., 8, 229–237, titograd. pamić, j., čelebić, đ. & jovanović, r. (1976): osnovne ekonomsko-geološke karakteristike jablaničkog gabra u hercegovini.– geol. glas., 21, 177–189, sarajevo. pamić, j. & kubat, i. (1976): novi prilog poznavanju čajničkih granita i okolnih željeznih i drugih mineralizacija.– geol. glas., 21, 153–162, sarajevo. pamić, j. (1977): petrologija trijaskih granit–sijenitskih stijena iz okolice čajniča u jugoistočnoj bosni.– glas srp. akad. nauka i umet., 42, 159–189, beograd. pamić, j., sunarić–pamić, o., olujić, j. & antić, r. (1977): petrografija i petrologija krivajsko–konjuškog ofiolitskog kompleksa i njegove osnovne geološke karakteristike.– acta geologica, 9/3, 135 p., zagreb. pamić, j. (1977): alpski magmatsko–metamorfni procesi kao indikatori geološke evolucije terena sjeverne bosne.– geol. glas., 22, 257–292, sarajevo. pamić, j. (1979): trijaska gabro–albit granosijenitska asocijacija radovanskog masiva (srednjobosanske škriljaste planine).– glas. srp. akad. nauka i umet., 45, 55–78, beograd. pamić, j. (1979): kontaktnometamorfne stijene na obodu trijaskog masiva radovana u srednjobosanskim škriljastim planinama.– geol. glas., 23, 93–110, sarajevo. pamić, j. & buzaljko, r. (1979): dioritske stijene zavajta kod foče (ji bosna).– geol. glas., 23, 39–46, sarajevo. pamić, j., šibenik-studen, m. & sijarić, g. (1979): postkonsolidacione promjene na bazičnim stijenama iz ofiolitske zone u bosni.– glas. zem. muz. u bih, 18, 25–36, sarajevo. pamić, j. & vrhovčić, j. (1979): geološko–petrološke karakteristike ladiničke i karničko–noričke vulkanogeno– sedimentne formacije iz okolice ključa (bosna).– spomenica b. milovanovića, zav. geol. geofiz. istr., 37, 123–134, beograd. pamić, j. (1979/80): petrološke karakteristike albitskih granosijenita ćusine kod jajca u bosni.– geol. glas., 24/25, 129–141, sarajevo. pamić, j. & mirković, m. (1980): srednjotrijaske magmatske stijene iz graničnih dijelova sjevernozapadne crne gore i jugoistočne bosne.– geol. glas., 9, 165–186, titograd. pamić, j. (1980): srednjotrijaski vulkaniti u području kalinovika i dobrog polja, južno od sarajeva.– geol. glas., 9, 145–163, titograd. pamić, j. (1981): ofioliti i ofioliti dinarida.– bilten, 3, lmgk, rud.-geol. fak., 175–184, beograd. pamić, j. (1981): naše dosadašnje saznanje o strukturnom stanju albita u vulkanitima srednjotrijaske spilit–keratofirske asocijacije dinarida.– geol. vjes., 33, 169–180, zagreb. pamić, j. & buzaljko, r. (1981): srednjotrijaski vulkaniti iz okolice tjentišta i sutjeske (ji bosna i sz crna gora).– geol. vjes., 35, 159–180, zagreb. pamić, j. (1982): bazaltne stijene trijaskog vulkanizma dinarida.– geol. vjes., 35, 159–180, zagreb. majer, v. & pamić, j. (1982): novi nalazi metamorfnih stijena u ofiolitskoj zoni u bosni.– geol. vjesn., 35, 153–157, zagreb. pamić, j. (1983): dijabaz–spilitske stijene jasenice iz ofiolitskog kompleksa mahnjače u bosni.– geol. vjesn., 36, 203–218, zagreb. pamić, j. & šparica, m. (1983): starost vulkanita požeške gore.– rad jazu, 404 (19), 183–189, zagreb. pamić, j., crnko, j. & jamičić, d. (1984): lamprofirska pojava sa psunj planine u slavoniji.– geol. vjesn., 37, 145–151, zagreb. pamić, j. & jamičić, d. (1984): bazične i intermedijarne magmatske stijene iz metamorfita središnjih dijelova psunja u slavoniji.– geol. vjes., 37, 127–144, zagreb. pamić, j., jamičić, d. & crnko, j. (1984): petrološki prikaz ultramafita iz metamorfnog kompleksa središnjih dijelova psunja.– rad jazu, 141 (20), 93–104, zagreb. pamić, j., krkalo, e. & prohić, e. (1984): granitne stijene sjeverozapadnog dijela moslavačke gore u sjeverozapadnoj hrvatskoj.– geologija, 27, 201–212, ljubljana. sijarić, g., pamić, j., šibenik-studen, m. & šćavničar, s. (1985): strukturni oblici albita u mezozojskim spilitima i keratofirima u bosni i hercegovini.– glasnik zemalj. muz. u bih, 24, 89 p., sarajevo. pamić, j. (1985): ofiolitski kompleks ljubića, čavke i snjegotine u sjevernoj bosni.– geol. macedonica, 2/1, 147–170, štip. pamić, j. (1985/86): kredno–tercijarne granitne i metamorfne stijene u dodirnom području sjevernih dinarida i panonskog strukturnog kompleksa.– geologija, 28–29, 219–237, ljubljana. pamić, j. & injuk, j. (1985/86): osnovne petrološko–geokemijske karakteristike ortogrinšistnih stijena zagrebačke gore u hrvatskoj.– geologija, 28–29, 239–254, ljubljana. 108 geologia croatica 57/1 109in memoriam – dr. sc. jakob pamić pamić, j. (1986): magmatsko–metamorfni procesi orogenih pojasova – kritički prikaz razvoja ideja.– geol. glas., 10, 109–145, titograd. pamić, j. & jamičić, d. (1986): metabasic intrusive rocks from the paleozoic radlovac complex of papuk mountain in slavonija (northern croatia, yugoslavia).– rad jazu, 424 (21), 97–127, zagreb. šparica, m. & pamić, j. (1986): prilog poznavanju tektonike požeške gore.– rad jazu, 424 (21), 85–96, zagreb. pamić, j. & šparica, m. (1986): metamorfne stijene požeške gore.– geol. vjes., 39, 95–102, zagreb. pamić, j. (1987): pojave kordijerita, andaluzita i margarita u metamorfnim stijenama s psunja u slavoniji.– geol. vjes., 40, 139–147, zagreb. pamić, j. (1987): granites and associated monzodiorites and gabbros from kamenac creek in mt. moslavačka gora (northern croatia, yugoslavia).– rad jazu, 431 (22), 179–199, zagreb. pamić, j. (1987): miocenski bazalti budima na sjevernim obroncima papuka južno od podravske slatine u slavoniji.– rad jazu, 431 (22), 53–67, zagreb. pamić, j. (1988): stijene granitno–granodioritne asocijacije krndije u slavoniji (sjeverna hrvatska).– rad jazu, 441 (23), 97–114, zagreb. pamić, j. (1988): mladoalpinski alkalijsko–feldspatski graniti (aljaskiti) požeške gore u slavoniji.– geologija, 30, 183–205, ljubljana. pamić, j. & šparica, m. (1988): badenian volcanics from mt. dilj in slavonija (northern croatia, yugoslavia).– bull. acad. serbe sci. arts. sci. natur., 28, 47–56, beograd. pamić, j., jurišić-mitrović, v., šibenik-studen, m. & sijarić, g. (1988): bazični vulkaniti stare tvrđave u doboju, u sjevernoj bosni (jugoslavija).– glasn. zem. muz. bih, 27, 65–78, sarajevo. pamić, j., lelkes-felvary, gy. & raffaelli, p. (1988): andalusite-bearing schists from southwestern parts of mt. papuk in slavonija (northern croatia).– geol. vjesn., 41, 145–157, zagreb. pamić, j., lanphere, m. & mckee, e. (1988): radiometric ages of metamorphic and associated igneous rocks of the slavonian mountains in the southern part of the pannonian basin.– acta geologica, 18, 13–39, zagreb. pamić, j. (1989): zonalnost hercinskog metamorfnog kompleksa krndije u slavoniji (sjev. hrvatska).– geol. vjesn., 42, 79–92, zagreb. pamić, j. & prohić, e. (1989): novi prilog petrološkom poznavanju alpinskih granitnih i metamorfnih stijena motajice u sjevernim dinaridima u bosni.– geol. glasn., 12, 145–176, titograd. šimunić, a. & pamić, j. (1989): ultramafitne stijene kod gornjeg orešja na sjeveroistočnim obroncima medvednice.– geol. vjesn., 42, 93–101, zagreb. pamić, j. (1990): alpinske(?) granitno–metamorfne stijene u podlozi panonskog bazena u bilogorsko–podravskom naftno–plinskom području.– nafta, 41/10, 433–437, zagreb. pamić, j. & marci, v. (1990): petrologija amfibolitskih stijena slavonskih planina (sjev. hrvatska).– geol. vjesn., 43, 121–133, zagreb. pamić, j., injuk, j. & jakšić, m. (1990): prilog geokemijskom poznavanju gornjokredne bimodalne vulkanske asocijacije požeške gore u slavoniji.– geologija, 31/32, 415–435, ljubljana. pamić, j. (1991): gornjokredne bazaltoidne i piroklastične stijene iz voćinske vulkanske mase na papuku (slavonija, sjev. hrvatska).– geol. vjes., 44, 161–172, zagreb. pamić, j. & olujić, j. (1991): ofiolitske stijene doline rzava (okolica višegrada) i njihov međusobni odnos.– zapisnici srp. geol. društva za 1987–1989. godinu, 135–141, beograd. pamić, j. (1992): trijaski vulkaniti iz nekih naftnih bušotina istočnih dijelova dravske potoline.– nafta, 46/4, 223–227, zagreb. pamić, j. (1992): alpinske i prealpinske metamorfne stijene prosare u sjevernoj bosni.– geologija, 35/1, 255–264, ljubljana. lanphere, m. & pamić, j. (1992): k–ar and rb–sr ages of alpine granite–metamorphic complexes in the northwesternmost dinarides and southwesternmost pannonian basin in northern croatia.– acta geologica, 22, 97–111, zagreb. pamić, j. (1992): trijaske i tercijarne vulkanske i piroklastične stijene iz murske depresije u hrvatskoj.– nafta, 43, 295–304, zagreb. pamić, j., belak, m. & slovenec, d. (1992): donjomiocenski trahiandeziti i šošoniti krndije u slavoniji (sjeverna hrvatska).– rad jazu, 463 (26), 27–47, zagreb. pamić, j. (1993): late cretaceous volcanic rocks from some oil-wells in the drava depression and adjacent mountains of the southern part of the pannonian basin (north croatia).– nafta, 44, 203–210, zagreb. šimunić, a., najdenovski, j. & pamić, j. (1993): chaotic rock complexes – possible hydrocarbon accumulations in the southwestern parts of the pannonian basin (r. of croatia).– nafta, 44, 609–616, zagreb. pamić, j. & pécskay, z. (1994): geochronology of upper cretaceous and tertiary igneous rocks from the slavonija– srijem depression (southern pannonian basin) and their basic petrological features.– nafta, 45, 331–339, zagreb. pamić, j. & pécskay, z. (1996): geological and k–ar ages of tertiary volcanic formations from the southern part of the pannonian basin, croatia – based on surface and subsurface data.– nafta, 47, 195–202, zagreb. pamić, j. & jurković, i. (1997): alpine magmatic– metallogenic formations of the northwestern and central dinarides.– rud. geol. naftni zbornik, 9, 1–9, zagreb. pamić, j. (1998): crystalline basement of the pannonian basin in croatia based on surface and subsurface data.– nafta, 49, 210–232, zagreb. pamić, j. (1999): kristalina podloga južnih dijelova panonskog bazena – temeljena na površinskim i bušotinskim podacima.– nafta, 50, 291–310, zagreb. 110 geologia croatica 57/1 111in memoriam – dr. sc. jakob pamić jurković, i. & pamić, j. (1999): triassic rifting-related magmatism and metallogeny of the dinarides.– acta geologica, 26, 1–26, zagreb. jurković, i. & pamić, j. (2001): geodynamics and metallogeny of variscan complexes of the dinarides and south tisia as related to plate tectonics.– nafta, 52/9, 267–294, zagreb. jurković, i. & pamić, j. (2002): the magnesites from dinarides.– rad hazu, 27, 77–110, zagreb. pamić, j. & hrvatović, h. (2003): main large thrust structures in the dinarides – a proposal for their classification.– nafta, 54/12, 443–464, zagreb. monographs pamić, j. (1964): magmatske i tektonske strukture u ultramafitima bosanske serpentinske zone.– poseb. izd. geol. glas., 2, 108 p., sarajevo. pamić, j., trubelja, f., varićak, d. & ramović, m. (1978): geologija bosne i hercegovine, knjiga 4: magmatizam i metalogenija.– posebno izdanje geol. glasnika, 274 p., sarajevo. šarac, m. & pamić, j. (1981): metalogenija trijaske zone niskomanganskih željeznih ruda u središnjim dinaridima.– poseb. izd. geol. glas., 251 p., sarajevo. pamić, j. (1982): trijaski magmatizam dinarida.– poseb. izd. “nafta”, 236 p., zagreb. sunarić-pamić, o. & pamić, j. (1988): žični magneziti ofiolitske zone dinarida u bosni i njihova geneza.– poseb. izd. geol. glasnika, 22, 173 p., sarajevo. pamić, j. (1990): alpinski granitoidi, migmatiti i metamorfiti moslavačke gore i okolne podloge panonskog bazena (sjev. hrvatska).– poseb. izd. razreda za prirod. znan., jazu, 10, 121 p., zagreb. pamić, j. & lanphere, m. (1991): hercinske granitne i metamorfne stijene papuka, psunja, krndije i okolne podloge panonskog bazena u slavoniji (sjev. hrvatska).– poseb. izd. geologija, 32, 172 p., ljubljana. pamić, j. (1997): vulkanske stijene savsko-dravskog međurječja i baranje (hrvatska).– poseb. izd. časopisa “nafta”, 192 p., zagreb. sheets and explanatory notes of basic geological map of sfry, 1:100,000 sunarić-pamić, o., pamić, j., kapeler, i., olujić, j. & zec, f. (1973): osnovna geološka karta sfrj, 1:100.000, list zavidovići.– savezni geološki zavod, beograd. pamić, j., sunarić-pamić, o., kapeler, i. & olujić, j. (1973): tumač osnovne geološke karte sfrj, 1:100.000, list zavidovići.– savezni geološki zavod, beograd, 55 p. đerković, b., đorđević, d., hohrajn, j., jojić, d., jurić, m., kačar, b., kapeler, i., kovačević, r., ložajić-maglov, m., maksimčev, s., pamić, j., sunarić-pamić, o., veljković, r. & vilovski, s. (1977): osnovna geološka karta sfrj, 1: 100.000, list prijedor.– savezni geološki zavod, beograd. mojičević, m., vilovski, s., tomić, b. & pamić, j. (1977): tumač osnovne geološke karte sfrj, 1:100.000, list banja luka.– savezni geološki zavod, beograd, 50 p. olujić, j., sunarić-pamić, o., pamić, j., milojević, r., veljković, d. & kapeler, i. (1978): osnovna geološka karta sfrj, 1:100.000, list vareš.– savezni geološki zavod, beograd. pamić, j., sunarić-pamić, o., olujić, j., milojević, r., veljković, d. & kapeler, i. (1978): tumač osnovne geološke karte sfrj, 1:100.000, list vareš.– savezni geološki zavod, beograd, 68 p. mojičević, m., pamić, j., maksimčev, s. & papeš, j. (1979): tumač osnovne geološke karte sfrj, 1:100.000, list bosanska krupa.– savezni geološki zavod, beograd, 54 p. strajn, v., mojičević, m., pamić, j., sunarićpamić, o., veljković, d. & đorđević, d. (1980): osnovna geološka karta sfrj, 1:100.000, list vlasenica.– savezni geološki zavod, beograd. strajn, v., mojičević, m., pamić, j., sunarićpamić, o., veljković, d. & đorđević, d. (1980): tumač osnovne geološke karte sfrj, 1:100.000, list vlasenica.– savezni geološki zavod, beograd, 61 p. sofilj, j., živanović, m. & pamić, j. (1980): tumač osnovne geološke karte sfrj, 1:100.000, list prozor.– savezni geološki zavod, beograd, 49 p. olujić, j., sunarić-pamić, o. & pamić, j. (1982): osnovna geološka karta sfrj, 1:100.000, list teslić.– savezni geološki zavod, beograd. buzaljko, r. & pamić, j. (1982): tumač osnovne geološke karte sfrj, 1:100.000, list foča.– savezni geološki zavod, beograd, 61 p. pamić, j., sunarić-pamić, o. & olujić, j. (1982): tumač osnovne geološke karte sfrj, 1:100.000, list teslić.– savezni geološki zavod, beograd, 65 p. sofilj, j., marinković, r. & pamić, j. (1985): tumač osnovne geološke karte sfrj, 1:100.000, list derventa.– savezni geološki zavod, beograd, 59 p. sofilj, j., marinković, r. & pamić, j. (1985): osnovna geološka karta sfrj, 1:100.000, list derventa.– savezni geološki zavod, beograd. olujić, j., pamić, j. & kapeler, i. (1987): osnovna geološka karta sfrj,1:100.000, list višegrad.– savezni geološki zavod, beograd. papers published in domestic and international monographs pamić, j. (1974): magmatske stijene bosne i hercegovine.– in: vidović, m. (ed.): geološki prilozi za izučavanje seizmičnosti terena bosne i hercegovine. 26–33, seizmološki zavod bih, sarajevo. pamić, j. (1974): middle triassic spilite–keratophyre association of the dinarides and its position in alpine magmatic–tectonic cycle.– in: amstutz, g.c. (ed.): spilites and spilitic rocks. 161–174, springer verlag, berlin–heidelberg–new york. 110 geologia croatica 57/1 111in memoriam – dr. sc. jakob pamić pamić, j. (1975): mineralni sastav i petrografija artefakata s lokaliteta crvene stijene u petrovićima.– zbornik radova “crvena stijena”, 205–209, titograd. pamić, j., marci, v., sijarić, g. & studen-šibenik, m. (1987): dijabaz–doleriti, bazalti i metabazalti iz ofiolitskog kompleksa okolice maglaja u bosni (jugoslavija).– zbornik radova posvećen akademiku z. bešiću, 187–203, crnogor. akad. nauka i umjetn., titograd. pamić, j., árkai, p., o’neil, j. & lantai, cs. (1992): very lowand low-grade progressive metamorphism of upper cretaceous sediments in mt. motajica, northern dinarides.– in: vozar, j. (ed.): special volume of igcp project, 276, 131–146, d. štur institute of geology, bratislava. pamić, j. & jurković, i. (1997): bosnia and herzegovina. – in: moores, e.m. & failbridge r.w. (eds.): encyclopedia of european and asian regional geology. 86–92, chapman & hall, encyclopedia of earth sciences series, davis, california. abstracts from international congresses pamić, j. (1968): middle triassic spilite–keratophyre association of the dinarides.– 23rd intern. geol. congr., abstracts, 65, praha. sikošek, b., ćirić, b., bešić, z., grubić, a., pamić, j., grandić, s. & papeš, j. (1967): geološki problemi dinarida.– xiii. kongr. karp.–balk. geol. asoc., 1–56, beograd. pamić, j. (1975): variation in geothermometry and geobarometry of the peridotite intrusions in the dinaride central ophiolite zone, yugoslavia.– international conference on geothermometry and geobarometry, abstracts, 147–150, univ. park, chicago. pamić, j., sunarić-pamić, o. & olujić, j. (1977): main characteristics of the dinaride ophiolites and their primary relations – a contribution to palinspastic interpretation.– dexime symp. concept. theor. evol. tect. de l’alpine, 22–29, beograd. pamić, j. (1977): similarities and dissimilarities of the ophiolites from the western parts of the alpine–himalaya belt as exemplified by the dinarides and hellenides.– in: janković s. (ed.): međunarodni simpozijum “metallogeny and plate tectonics”. rud.–geol. fakultet, 101–112, beograd. pamić, j. & mojičević, m. (1977): geology of the middle parts of the dinarides in the light of plate tectonics.– dexime symp. concept. theor. evolut. de l’alpine, 30–36, beograd. adib, d. & pamić, j. (1979): rodingites from the southeastern parts of the neyriz ophiolite complex in the zagros range, iran.– intern. symp. on inclusions in ultramafics. abstracts, 23, geneve. pamić, j. (1980): etapes tectoniques des chaines alpines: correlation des phases de deformation, de metamorphism et de magmatisme: dinarides.– 26th intern. geol. congr. colloq., 5, 304–306, paris. pamić, j. & sestini, g. (1980): mélanges and mélanges in the zagros range, iran.– 26th intern. geol. congr., abstracts, 1, 88, paris. pamić, j. (1980): correlation between mesozoic spilite–keratophyre associations of continental and oceanic crust origin as exemplified by the dinarides.– 26th intern. geol. congr., abstracts, 70, paris. pamić, j. & adib, d. (1980): ultramafic and mafic cumulates from the neyriz ophiolite complex in se parts of the zagros range (iran).– ophiolites, proceed. intern. ophiol. symp., 392–397, cyprus, nicosia. đorđević-knežević, v., karamata, s. & pamić, j. (1982): triassic rifting and development of oceanic basins in the dinarides.– meeting on “the geological evolution of the eastern mediterranean”. abstracts, 34, edinburgh. pamić, j. (1983): permo–triassic rift faulting and magmatism of the dinarides.– ann. soc. geol. france, tc iii, 133–141, lille. pamić, j. (1987): hercynian and alpine granitic–metamorphic complexes of the adjoining area of the dinarides and pannonian basin in yugoslavia as related to geodynamics.– “geologija karpatsko–balkanskog pojasa”, bratislava. karamata, s., majer, v. & pamić, j. (1988): mafic and ultramafic rock associations – indicators of tectonic setting.– “geotektonska evolucija karpatsko–balkanskog pojasa”, bratislava. pamić, j. & lanphere, m. (1989): petrology and geotectonic position of alpine a-granites from southern parts of the pannonian basin in northern yugoslavia.– 14th congr. carp.–balk. geol. assoc., extended abstracts, 230–232, sofia. pamić, j. (1992): younger alpine magmatic and metamorphic processes in the adjoining area of the northern vardar zone, the eastern periadriatic zone and the southern pannonian basin.– alpaca intern. meeting, terra nova, abstracts, 2, 119, graz. pamić, j. (1992): terranes of the adjoining area of the northernmost dinarides and southwestern pannonian basin.– alpaca intern. meeting, terra nova, abstracts, 2, 50, graz. pamić, j., jelaska, v., gušić, i., šikić, k., belak, m. & tomić, v. (1995): tectonostratigraphic units and terranes between the adriatic sea and southern pannonian basin.– symp. of igcp project no. 276, abstract, 21–22, budapest. jurković, i. & pamić, j. (1995): permo–triassic riftingrelated magmatic–metallogenic formations of the northwestern and central dinarides.– symp. of igcp project no. 369, abstract, 97, athens. pamić, j., gušić, i. & jelaska, v. (1996): geodynamic evolution of the central dinarides.– pancardi conference – europ. sci. union, abstracts, 124–125, vienna. tari-kovačić, v. & pamić, j. (1996): geodynamic evolution of the north dinarides and pannonian basin.– pancardi conference – europ. sci. union, abstracts 138–139, vienna. jurković, i., pamić, j., šiftar, d. & palinkaš, l. (1997): geochemical characteristics of late proterozoic– early paleozoic, variscan and alpine magmatic–metallogenic formations of the dinarides.– 9th meeting of european geosciences, abstracts, abstract supplement terra nova, 9, 533, strasbourg. 112 geologia croatica 57/1 113in memoriam – dr. sc. jakob pamić pamić, j. (1997): late cretaceous–paleogene subductionrelated lithologies of the north dinarides included in the south tisia in croatia.– pancardi conference – europ. sci. union, przegled geologiczny, 1109, krakow. tomljenović, b. & pamić, j. (1997): mixed alpine and dinaridic lithologies of mt. medvednica located along the zagreb–zemplen line.– pancardi conference – europ. sci. union, przegled geologiczny, 1109, krakow. márton, e., márton, p. & pamić, j. (1998): a puzzling piece of the pannonian puzzle: tertiary paleomagnetic results from the w part of the tisza–dacia megaunit.– europ. geophys. soc. symposia, abstract, 221, nant. haas, j., mioč, p., pamić, j., tomljenović, b., árkai, p., berczi-makk, a., kovács, s. & ralish-felgenhauer, e. (1998): continuation of the periadriatic and dinaridic units in the basement of the pannonian basin.– 16th congr. cbga, proceed., 199, vienna. kovács, s., pamić, j., vozar, j., mioč, p. & kräutner, h. (1998): evolutionary stages of the circumpannonian region.– 16th congr. cbga, proceed., 305, vienna. pamić, j. (1999): vardar zone of the dinarides and hellenides versus the vardar ocean.– 4th workshop on alpine geological studies, tübinger geowiss. arbeiten, a, 52, 106–107, tübingen. pamić, j. (1999): pre-mesozoic tectonostratigraphic units of the dinarides and south tisia.– europrobe tezs, pancardi, georift meeting, rom. j. tect. reg. geol., 77/1, 28–29, tulcea/bucuresti. balen, d. & pamić, j. (2000): the clinopyroxene crystallization pressure variations from the alpine volcanic associations of the dinarides.– vijesti hrvatskog geološkog društva, 37/3, 16–17, pancardi 2000, abstracts, dubrovnik. hamzabegović, a., sijarić, g., pamić, j. & hrvatović, h. (2000): crust of weathering of peridotites from the žepče area, the dinaride ophiolite zone in bosnia.– vijesti hrvatskog geološkog društva, 37/3, 49, pancardi 2000 abstracts, dubrovnik. márton, e., drobne, k., pamić, j., jelen, b., márton, p., ćosović, v., pavelić, d., tomljenović, b. & avanić, r. (2000): from the adriatic foreland to the sw part of the pannonian basin: tectonic implications of tertiary paleomagnetic results.– vijesti hrvatskog geološkog društva, 37/3, 80, pancardi 2000, abstracts, dubrovnik. palinkaš, a.l., balogh, k., strmić, s., pamić, j. & bermanec, v. (2000): ar–ar dating and fluid inclusion study of muscovite from the pegmatite of srednja rijeka, within granitoids of moslovačka gora mt., north croatia.– vijesti hrvatskog geološkog društva, abstracts 37/3, 95–96, pancardi 2000, dubrovnik. mioč, p. & pamić, j. (2000): the internal dinaridic units in the adjoining area of the alps and dinarides in slovenia.– vijesti hrvatskog geološkog društva, abstracts, 37/ 3, 143–144, pancardi 2000, dubrovnik. pamić, j. (2001): the internal dinarides and their dismembered fragments in the south pannonian basin.– pancardi abstracts, 2, do, 1–2, sopron. tari, v. & pamić, j. (2001): oligocene formations in the south pannonian basin in croatia.– pancardi, abstracts, dp–14, 1–2, sopron. balen, d., pamić, j. & tomljenović, b. (2001): metamorphic sole amphibolites from the dinaride ophiolite zone (doz) and sava–vardar (svz) of the dinarides.– pancardi, abstracts, dp–1, 1–2, sopron. pamić, j., balogh, k., hrvatović, h., balen, d., jurković, i. & palinkaš, l. (2001): polyphase metamorphic evolution of the mid-bosnian schists mts. (mbsm) paleozoic complex from the central dinarides (bosnia and hercegovina).– pancardi, abstracts, dp–12, 1–2, sopron. pamić, j., tomljenović, b. & balen, d. (2001): twostage evolution of the alpine dinaridic ophiolites.– pancardi, abstracts, dp–13, 1–2, sopron. dunkl, i., árkai, p., balen, d., balintoni, i., berza, t., biron, a., csontos, l., frisch, w., fritz, h., hoxha, l., janák, m., kázmér, m., koller, f., koroknai, b., lelkes-felvári, gy., milovanović, d., most, th., tóth, t. m., nakov, r., palinkaš, l., pamić, j., plasienka, d., puste, a., putiš, m., schuster, r., székely, b., thöni, m., tomljenović, b., török k. & vrabec m. (2002): web edition of the metamorphic map and database of carpatho–balkan–dinaride area (http: //www.uni-tuebingen.de/geo/met-map/index.html).– in: michalík, j., šimon, l. & vozár, j. (eds.): proceedings of xvii. congress of cbga. geologica carpathica, 53, 161–164, bratislava. judik, k., tibljaš, d., balen, d., tomljenović, b., horváth, p., pamić, j. & árkai, p. (2002): new data on the low-temperature metamorphism of mt. medvednica and the slavonian mts. (croatia).– in: michalík, j., šimon, l. & vozár, j. (eds.): proceedings of xvii. congress of cbga. geologica carpathica, 53, cd edition, bratislava. judik, k., tibljaš, d., balen, d., tomljenović, b., horváth, p., pamić, j. & árkai, p. (2003): contribution to the knowledge on the low-temperature metamorphism of mt. medvednica, croatia.– euroclay 2003, abstracts, 144–145, modena. balen, d., operta, m. & pamić, j. (2003): the geothermobarometry of alpine amphibolites from the metamorphic sole of the krivaja–konjuh ultramafic massif (dinaride ophiolite zone).– 6th workshop alpine geological studies, sopron 2003, ann. univer. sci. budapest., sec. geol., 35, 131–132. neubauer, f., pamić, j., dunkl, j. & handler, j. (2003): exotic granites in the cretaceous pogari formation overstepping the dinaridic ophiolite zone mélange in bosnia.– 6th workshop alpine geological studies, sopron 2003, ann. univer. sci. budapest., sec. geol. 35, 133–134. kovács, s., breznyansky, k., haas, j., szederkenyi, t., ebner, f., pamić, j., gaetani, m., vaì, g.-p., kräutner, h., vozár, j., vozárová, a., mioč, p., karamata, s. & krstić, b. (2003): 112 geologia croatica 57/1 113in memoriam – dr. sc. jakob pamić tectonostratigraphic terrane and paleoenvironment maps of the circum–pannonian region.– 6th workshop alpine geological studies, sopron 2003, ann. univ. sci. budapest, sec. geol., 35, 65. papers and abstracts from domestic congresses trubelja, f. & pamić, j. (1957): pregled magmatizma bosne i hercegovine.– ii. kong. geol. fnrj, 73–88, sarajevo. pamić, j. (1959): karakteristike magmatskih stijena iz dijabaz–rožnjačke serije u okolici jablanice i prozora.– iii. kong. geol. fnrj, 363–382, budva. pamić, j. (1960): osnovne karakteristike trijaskih vulkanita u širem području kalinovika.– simp. probl. alps. inicij. magmat., 5, 1–12, ilidža–sarajevo. karamata, s. & pamić, j. (1960): gabrovi, dijabazi i spiliti područja tribije (vareš).– simp. probl. alps. inicij. magmat., 3, 1–15, ilidža–sarajevo. pamić, j. & trubelja, f. (1962): osnovne geološko– petrološke karakteristike ozren planine u sjeveroistočnoj bosni.– refer. v. savet. geol. druš. fnrj, 2, 117–123, beograd. pamić, j. (1967): trijaski magmatizam u dinaridima.– i. kolok. geol. asoc. dinarida, 177–185, ljubljana. pamić, j. (1972): strukturno–teksturne karakteristike bosanskih peridotita kao osnova za genetska razmatranja.– vii. kongr. geol. sfrj, 2, 271–296, zagreb, 1970. pamić, j. (1972): u spilit–keratofirskoj asocijaciji dinarida javljaju se albiti u kojima optika na osnovi teodolitno–mikroskopskih podataka stvarno tendira prema visokotemperaturnoj optici.– vii. kongr. geol. sfrj, 2, 43–58, zagreb, 1972. karamata, s. & pamić, j. (1972): razmatranje o genezi alpinotipnih ultramafita dinarida.– vii. kongr. geol. sfrj, 2, 139–156, zagreb, 1970. pamić, j. & đorđević, d. (1974): o problemu kiselih i intermedijarnih intruzivnih stijena u bosanskoj serpentinitskoj zoni.– iii. simp. dinar. asoc., 2, 127–140, zagreb, 1968. mojičević, m. & pamić, j. (1975): mezozojska evolucija središnjih dijelova dodirnog područja unutrašnjih i spoljašnjih dinarida u svjetlu tektonike ploča.– ii. znan. skup znan. savj. za naftu jazu, a, 5, 118–125, zagreb. pamić, j. (1975): velike poprečne frakture (transformni rasjedi?) u unutarnjim dinaridima.– ii. god. znan. skup znan. savj. za naftu jazu, a, 5, 126–137, zagreb. pamić, j. (1975): sastav paleozojsko–mezozojskih pješčenjaka kao prilog za paleogeografske interpretacije unutrašnjih dinarida.– ii. god. znan. skup znan. savj. za naftu jazu, a, 5, 103–108, zagreb. pamić, j. & jelaska, v. (1975): pojave vulkanogeno– sedimentnih tvorevina gornje krede i ofiolitnog melanža u sjevernoj bosni i njihov značaj u geološkoj građi dinarida.– ii. god. znan. skup znan. savj. za naftu jazu, a, 5, 109–117, zagreb. pamić, j. (1976): eklogitske stijene u ofiolitskoj zoni dinarida.– viii. jugosl. geol. kongr. 1, 211–230, bled. pamić, j. (1978): albitni intruzivni ekvivalenti srednjotrijaske spilitno–keratofirske asocijacije dinarida.– ix. kongr. geol. sfrj, 466–471, sarajevo. pamić, j., sestini, g. & adib, d. (1978): korelacija dinarida i zagrosida u svjetlu tektonike ploča.– ix kong. geol. sfrj, 232–241, sarajevo. jelaska, v. & pamić, j. (1978): sedimentacijski i magmatski procesi mlađeg mezozoika na području sjeverne bosne.– zbor. rad. iv. znan. skupa sek. primj. geol. geofiz. i geokem. jazu, 85–99, stubičke toplice. pamić, j. & šarac, m. (1978): karakteristike trijaske magmatsko–metalogenetske zone s niskomanganskim željeznim rudama u središnjim i jugoistočnim dinaridima.– ix. kong. geol. sfrj, 674–688, sarajevo. pamić, j., šibenik-studen, m. & sijarić, g. (1979): postkonsolidacione promjene na bazičnim stijenama iz ofiolitske zone u bosni.– simp. “hidrotermalne alteracije”, 83, beograd. pamić, j. (1980): položaj trijaskih magmatsko–metalogenetskih kompleksa u geološkoj građi dinarida.– simp. region. geol. paleont., 100 god. geol. nauke i škole u srbiji, 260– 274, beograd. pamić, j. (1980): geološka i izotopna starost riftnog magmatizma mezozojskog wilsonovog ciklusa dinarida.– simp. region. geol. paleont., 100 god. geol. nauke i škole u srbiji, 251–259, beograd. pamić, j. (1981): ofioliti i ofioliti dinarida.– simpozijum 10. godiš. lmgk, rud-geol. fak., sažetak, 24, beograd. pamić, j. (1982): lercolitska i harcburgitska provincija dinarida i sjevernih helenida.– x. jubil. kongr. geol. jugoslavije, 2, 351–362, budva. pamić, j. (1986): metamorfiti temeljnog gorja panonskog bazena u savsko–dravskom međuriječju na osnovi podataka naftnih bušotina.– xi. kongr. geol. jugosl., 2, 259–272, tara. raffaelli, p. & pamić, j. (1986): petrokemijsko razmatranje predalpinskih i mladoalpinskih granitnih masa dodirnog područja sjevernih dinarida i panonskog masiva.– xi. kongr. geol. jugosl., 2, 293–305, tara. pamić, j. & injuk, j. (1988): alpinske granitoidne stijene prosare u sjevernoj bosni.– zbor. ref. nauč. skupa “minerali, stijene, izumrli i živi svijet bih”, 93–103, sarajevo. belak, m., pamić, j., kolar-jurkovšek, t., pécskay, z. & karan, d. (1995): alpinski niskometamorfni regionalni kompleks planine medvednice, sjeverozapadna hrvatska.– 1. hrv. geol. kongr., zbor. radova 1, 67–70, opatija. pamić, j. (1997): geološka shvaćanja o dinaridskim ofiolitima kroz razvoj hrvatske geoznanosti.– znanstveni skup u povodu 80. godišnjice života akademika milana heraka, zagreb. pamić, j. (2000): periadriatsko–savsko–vardarska suturna zona.– ii. hrvatski geološ. kongres, zbornik radova, 1, 333–337, cavtat–dubrovnik. pamić, j., gušić, i. & jelaska, v. (2000): alpinske tektonostratigrafske jedinice dinarida i njihova geodinamska evolucija.– ii. hrvatski geološ. kongres, zbornik radova, 1, 15–22, cavtat–dubrovnik. 114 geologia croatica 57/1 115in memoriam – dr. sc. jakob pamić scientific notes published in bulletin scientifique of the academy of science pamić, j. (1968): amphibolite rocks of the inner dinarides in bosnia.– bull. scie., a, 14/9–10, 295–296, zagreb. pamić, j. (1969): high-temperature feldspars from the middle triassic spilite–keratophyre association of the dinarides.– bull. scie., a, 14, 1–2, zagreb. pamić, j. (1970): syenite and granite rocks associated with talc deposits on the ozren ultramafic massif (bosnia).– bull. scie., a, 15/9–10, 315–316, zagreb. pamić, j. (1971): amphibolites associated with the large krivaja–konjuh ultramafic massif (yugoslavia).– bull. scie., a, 16/1–2, 3–4, zagreb. pamić, j. (1971): metamorphic grade of the jurassic magmatic–sedimentary (“diabas–hornstein”) formation of the dinaridic ophiolite zone (yugoslavia).– bull. scie., a, 17/5–6, 151–152, zagreb. pamić, j. (1973): amphibolite peridotite (cortlandite) from the vijenac amphibolite–ultramafic mass in the ophiolite zone of bosnia, yugoslavia.– bull. scie., a, 18/4–6, 72–73, zagreb. majer, v. & pamić, j. (1974): metamorphosed graywackes and shales on the nw border of the borje ultramafic massif in bosnia (yugoslavia).– bull. scie., a, 19/11–12, 334–335, zagreb. sijerčić, z., pamić, j., jovanović, č. & šljukić, m. (1974): analcimolites in the tuzla salt series (bosnia).– bull. scie., a, 19/5–6, 131–132, zagreb. pamić, j. (1976): trondhjemitic differentiates from sw border of the radovan gabbro–diorite mass in the middle bosnia.– bull. scie., a, 21/10–12, 201–202, zagreb. professional papers a) editorial works čičić, s. & pamić, j. (eds.) (1977–1984): geologija bosne i hercegovine. tom i (1977, 103 p.), ii (1984, 315 p.), iii (1977, 278 p.), iv (1978, 274 p.).– geoinženjering, sarajevo. krkalo, e. (1998): ležišta neogenskih kvarcnih pijesaka u rubnim područjima slavonskih planina (hrvatska).– pamić, j. (ed.), inst. geol. istraživanja, zagreb, 174 p. pamić, j. & tomljenović, b. (eds.) (2000): outline of the geology of the dinarides and south tisia.– pancardi 2000, 153, dubrovnik. pamić, j., radonić, g. & pavić, g. (2003): geološki vodič kroz park prirode papuk.– 66 p., požega. b) notes pamić, j., gušić, i. & jelaska, v. (2000): basic geological features of the dinarides and south tisia.– in: pamić, j. & tomljenović, b. (eds.): outline of the geology of the dinarides and south tisia. 9–18, zagreb. pamić, j. (2000): the sava–vardar zone (svz).– in: pamić, j. & tomljenović, b. (eds.): outline of the geology of the dinarides and south tisia. 19–22, zagreb. balen, d. & pamić, j. (2000): crystalline complex of mt. moslavačka gora.– in: pamić, j. & tomljenović, b. (eds.): outline of the geology of the dinarides and south tisia. 44–47, zagreb. pamić, j. (2000): variscan crystalline complex of the slavonian mts.– in: pamić, j. & tomljenović, b. (eds.): outline of the geology of the dinarides and south tisia. 48–52, zagreb. pamić, j. & belak, m. (2000): late cretaceous volcanic–sedimentary complex of mt. požeška gora in slavonia.– in: pamić, j. & tomljenović, b. (eds.): outline of the geology of the dinarides and south tisia. 53–57, zagreb. pamić, j. & hrvatović, h. (2000): basic data on the geology and petrology of the krivaja–konjuh ophiolite complex.– in: pamić, j. & tomljenović, b. (eds.): outline of the geology of the dinarides and south tisia. 60–67, zagreb. balen, d. & pamić, j. (2000): the oligocene maglaj shoshonite and high-k calc–alkaline volcanics.– in: pamić, j. & tomljenović, b. (eds.): outline of the geology of the dinarides and south tisia. 68–69, zagreb. pamić, j. (2000): radiolarite formation.– in: pamić, j. & tomljenović, b. (eds.): outline of the geology of the dinarides and south tisia. 70–71, zagreb. pamić, j. (2000): triassic jablanica gabbro pluton in north hercegovina.– in: pamić, j. & tomljenović, b. (eds.): outline of the geology of the dinarides and south tisia. 77–80, zagreb. c) university text-books pamić, j. (1971): osnovi petrologije.– sveučilište u sarajevu, 150 p.; 2nd ed. 1987., 165 p. sarajevo. ristić, p. & pamić, j. (1981): petrografija i petrologija magmatskih stijena.– svjetlost, 272 p., sarajevo. pamić, j. (1996): magmatske formacije dinarida, vardarske zone i južnih dijelova panonskog bazena.– nafta, 225 p., zagreb. d) reviews pamić, j. (1976): granati, korundi i duniti ofiolitske zone u bosni.– in: varićak, d. (ed.): mineralne sirovine bosne i hercegovine. 2, poseb. izd. geoinženjeringa, sarajevo. pamić, j. (1978): jurski magmatizam – područje borja i mahnjače.– in: pamić, j. (ed.): geologija bosne i hercegovine. 4, 191–205, pos. izd. geol. glas., sarajevo. pamić, j. (1978): jurski magmatizam – područje kozare i pastireva.– in: pamić, j. (ed.): geologija bosne i hercegovine. 4, 207–217, pos. izd. geol. glas., sarajevo. pamić, j. (1978): vulkaniti sansko–unskog paleozoika.– in: pamić, j. (ed.): geologija bosne i hercegovine. 4, 35–36, pos. izd. geol. glas., sarajevo. pamić, j. (1978): srednjotrijaski magmatizam – trijaski magmatiti područja prozora, jablanice i konjica.– in: pamić, j. (ed.): geologija bosne i hercegovine. 4, 51–67, pos. izd. geol. glas., sarajevo. pamić, j. (1978): srednjotrijaski magmatizam: srednjotrijaski magmatiti jugoistočne bosne.– in: pamić, j. (ed.): 114 geologia croatica 57/1 115in memoriam – dr. sc. jakob pamić geologija bosne i hercegovine. 4, 83–94, pos. izd. geol. glas., sarajevo. pamić, j. (1978): jurski magmatizam – krivajsko–konjuški ofiolitski kompleks.– in: pamić, j. (ed.): geologija bosne i hercegovine. 4, 99–133, pos. izd. geol. glas., sarajevo. pamić, j. (1978): jurski magmatizam – ozrenski ofiolitski kompleks.– in: pamić, j. (ed.): geologija bosne i hercegovine. 4, 135–162, pos. izd. geol. glas., sarajevo. pamić, j. (1978): jurski magmatizam – područje ljubića, čavke, skatavice, snjegotine i vrbanje.– in: pamić, j. (ed.): geologija bosne i hercegovine. 4, 177–190, pos. izd. geol. glas., sarajevo. e) other contributions pamić, j. & sijerčić, z. (1969): klasifikacija karbonatskih i klastičnih stijena.– translation from english, geol. glas., 13, 3–74, sarajevo. pamić, j. (1975): značaj katzera za razvitak bosansko–hercegovačke petrologije.– geol. glas., 20, spomenica f. katzeru, 177–183, sarajevo. pamić, j. (1975): luka marić: in memoriam, nekrolog.– geol. glas., 23, 320–325, sarajevo. pamić, j. (1979): ofioliti polarnog urala.– zap. srp. geol. društva za 1979. godinu, 113–121, beograd. pamić, j. & čićić, s. (1979): naučno–istraživački rad i publicistička aktivnost u okviru “geoinženjeringa”, sarajevo.– akad. nauka i umj. bih, pos. izd., 69, 401–407, sarajevo. pamić, j. (1979): o dosadašnjem razvoju i dosadašnjem stanju mineraloško–petroloških ispitivanja u bosni i hercegovini.– akad. nauka i umj. bih, pos. izd., 69, 375–380, sarajevo. pamić, j. (1982): prikaz knjige “gill, k., 1981: orogenic andesites and plate tectonics”, izd. springer verlag, berlin.– geol. vjes., 35, 287–288, zagreb. pamić, j. (1983): prikaz knjige “scheidegger, a.e. (1982): principles of geodynamics”. izd. springer verlag, berlin.– geol. vjes., 36, 343–344, zagreb. pamić, j. & dimitrijević, m. (1983): prikaz knjige “borradaile, g.j., m.b. bayly and b.j. wood (1982): atlas of deformational and metamorphic rock fabrics”. izd. springer verlag, berlin.– geol. vjes., 36, 341–343, zagreb. pamić, j. (1983): komentar trubeljinom radu “osvrt na dio sadržaja članka “naše dosadašnje saznanje o strukturnom stanju albita u vulkanitima srednjotrijaske spilitno–keratofirske asocijacije dinarida””.– geol. vjes., 36, 319–320, zagreb. pamić, j. (1989): izotopna geologija i neki primjeri njene primjene.– nafta, 40/1, 9–18, zagreb. pamić, j. & krkalo, e. (1993): geološka zbirka franjevačkog samostana u požegi i kajo agjić.– zbor. radova o kaji agjiću, 231–243, ispostava hazu vinkovci, 1996. pamić, j. (1994): doprinos i važnost gjure pilara u geološkom istraživanju bosne i hercegovine.– zbornik znan. skupa o gjuri pilaru, sl. brod, 1993. posebno izdanje razreda za prirodne znanosti hazu, 11, 85–94, zagreb, 1994. palinkaš, l., pamić, j. & bermanec, v. (2000): mineralogija, petrologija i znanost o rudnim ležištima u hrvatskoj, jučer, danas, sutra.– ii. hrvatski geološ. kongres, cavtat–dubrovnik, zbornik radova, 1, 1–6, zagreb. pamić, j. (2002): sjećanje na peru mioča.– vijesti hgd-a, 38/2, 73–74, zagreb. majer, v. & pamić, j. (2002): mijo kišpatić – njegovo znanstveno djelo.– in: “mijo kišpatić 1851–1926”. 11–26, hrv. akad. znanosti, zagreb. pamić, j. (2003): in memoriam pero mioč.– acta geol. hungarica, 46/1, 127–128, budapest. pamić, j. (2004): položaj geologije u našim prirodnim znanostima.– priroda, 2, 48–49, zagreb. 116 geologia croatica 57/1 2022 | 75/1 | 3–16 | 9 figs. | 6 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction landslides have been in the focus of many researchers in the field of engineering geology, geotechnics, and geomorphology for many years, especially because they present a geohazard event that can cause extensive damage and casualties (varnes & iaeg, 1984; bell, 2003; haque et al., 2016; mihalić arbanas et al., 2017), and significantly contribute to landform evolution (crozier, 2010; bell et al., 2012). for landslide analysis related to both of these subjects, preparation of a landslide inventory map for a particular area is an initial step (guzzetti et al., 2012), as it is believed that the locations of past and present landslides are the key to predicting future ones (varnes & iaeg, 1984). a landslide inventory primarily records the landslide location and, when known, the type of movement, activity, date of occurrence, and other landslide characteristics (malamud et al., 2004; fell et al., 2008). techniques of landslide mapping are constantly developing. in particular, detailed information about surface topography provided by airborne laser scanning (als), also known as airborne light detection and ranging (lidar), improved the investigation of the earth’s surface processes (jaboyedoff et al., 2012; tarolli, 2014). in landslide studies, the use of lidar has grown greatly during the last decade and has become a promising method for landslide mapping, monitoring, and modelling (derron & jaboyedoff, 2010). considering the lidar-based landslide inventories, many authors have highlighted the advantages of surface interpretation using bare earth high-resolution (hr) lidar digital terrain models (dtm) over conventional methods, i.e., geomorphological field mapping and visual inter spatial distribution and geometric characteristics of landslides with special reference to geological units in the area of slavonski brod, croatia iris bostjančić*, radovan avanić, tihomir frangen and mirja pavić croatian geological survey, sachsova 2, 10000 zagreb, croatia; (*corresponding author: iris.bostjancic@hgi-cgs.hr) doi: 10.4154/gc.2022.03 abstract a preliminary analysis of landslide spatial distribution and their geometric characteristics is presented for the area of slavonski brod, located in the northeastern part of croatia and belonging to the pannonian basin system. a landslide inventory for the study area of 55.1 km2 is accomplished for the first time, based on the visual interpretation of a high resolution lidar digital terrain model. in total, 854 landslide polygons are delineated, corresponding to an average density of 15.5 landslides per square kilometre. the average landslide area is 839 m2, and most of the landslides can be classified as small landslides (76 %). the spatial relationship between landslides and geological units is analysed and expressed as a landslide index. the late pannonian sands with silts and gravel interlayers and pliocene clay, sands, gravels, and coal are determined as the units that are most susceptible to landslide processes. the majority of landslides (85 %) are concentrated within these two units, for which a detailed analysis is performed, determining the morphometric parameters (slope and relief) and drainage network. the parameters’ classes that create favourable preconditions to slope instabilities are defined, based on the landslide density within individual classes. besides, the geometric characteristics of landslides (size and shape) within these two units are compared. the results serve as the basis for further investigations. they help to foresee the area of future landslides through landslide susceptibility maps, and offer a better understanding of the influence of fluvial-denudation and slope processes on recent landscape evolution and form. pretation of stereoscopic aerial photographs (e.g., van den eeckhaut et al., 2007; jaboyedoff et al., 2012; guzzetti et al, 2012; görüm, 2019). the application of visual interpretation techniques are tested for different landslide types and under a wide range of environmental conditions (e.g., ardizzone et al., 2007; van den eeckhaut et al., 2007; petschko et al., 2016; bernat gazibara et al., 2019; pawluszek, 2019; görüm, 2019; jagodnik et al., 2020). along with the increasing availability of hr digital elevation models, advances in geographical information system (gis) have improved quantitative analysis of the earth’s surface, including landslide zonation studi es related to inventory, and susceptibility, hazard or risk assessment (van westen, 2000; chacon et al., 2006). until now, in croatia, lidar-based landslide inventories exist for smaller areas of the city of zagreb and the vinodol valley. in the populated area of the city of zagreb, 24 km2 (mihalić arbanas et al., 2016), and 21 km2 (bernat gazibara et al., 2019) were examined. in the vinodol valley, 18.55 km2 were studied in the central part of the dubračina river basin (toševski, 2013), and 0.48 km2 in the slani potok gully (jagodnik et al., 2020). the study area is one of the six pilot areas selected in the framework of the safearth project (“transnational advanced management of land use risk through landslide susceptibility maps design”), which was carried out from 2017 to 2019 under the interreg ipa cross-border cooperation programme croatiabosnia and herzegovina-montenegro 2014-2020. the main project goals were related to landslide susceptibility maps at different scales. for the project implementation, an als was performed, article history: manuscript received december 08, 2020 revised manuscript accepted july 02, 2021 available online february 28, 2022 keywords: landslide inventory, lidar, geological units, landslide spatial distribution, north croatian basin g eo lo gi a c ro at ic a 4 geologia croatica 75/1 which resulted in hr dtms for an area of the app. 300 km2 in total. it gave the opportunity to accomplish landslide inventories over a wide area and increased the knowledge of landslide characteristics and their spatial distribution. the pilot area presented in this paper (55.1 km2) is located in the northeastern part of croatia, in the hinterland of slavonski brod. it represents the southwestern part of the pannonian basin system (horváth & royden, 1981; royden, 1988) and belongs to the north croatian basin (pavelić & kovačić, 2018). in this area, mostly miocene, pliocene, and quaternary sediments are exposed on the surface (šparica et al., 1979a; šparica, 1986). most of the study area is covered by forest, and the most populated area, the centre of slavonski brod, is outside of the study area. however, the expansion of the settlements towards the north resulted in the highest city elevations of approx. 250 m. landslide occurrence and damage to property have been recently documented after a period of heavy precipitation in march 2018. while severe damage occurred to private houses and local road infrastructure, a natural disaster was declared for the hilly areas of slavonski brod. this has led to increased interest in landslide processes and related problems by the local authorities. here, a lidar-based landslide inventory for the area of slavonski brod has been completed for the first time. the preliminary results presented aim to define the landslide spatial distribution and geometric characteristics within different geological units (gus). this was accomplished through several steps: (i) identifying and mapping landslide polygons using hr lidar dtm derivatives, (ii) correlating the landslide distribution with gus identified within the study area, (iii) defining morphometric characteristics within the two most representative gus, and (iv) examining in more detail the relationship between morphometric parameters and landslide occurrence, as well as differences in landslide geometric characteristics within these units. 2. study area 2.1. geographical and geomorphological settings the study area is located in the northeastern continental part of croatia (fig. 1a) and covers an area of 55.1 km2. the area is situated northwest of the city of slavonski brod, the main centre of brod-posavina county (fig. 1b), and covers the area of three municipalities, slavonski brod, podcrkavlje, and sibinj (fig. 1c). slavonski brod is situated at the junction of two spatial units. the larger, southern part of the city area belongs to the lowland area along the sava river, and the smaller, northern part, to the wider hilly belt, in the hinterland of which is dilj mt. with the highest peak of 461 m. several suburban settlements are situated within the study area, where 11 % (app. 7,100 inhabitants) of the population of slavonski brod (bpž, 2019) reside in podvinje and brodsko vinogorje. in these settlements, landslides were reported to figure 1. location map of the study area: brod-posavina county in croatia (a); the study area northwest of the city of slavonski brod (b); elevation map derived from lidar dtm and drainage network obtained from the 1:25.000 topographic map (c). g eologia c roatica 5bostjančić et al.: spatial distribution and geometric characteristics of landslides with special reference to geological units in the area of slavonski brod local authorities in 2010 and 2018, when a large amount of precipitation was recorded. according to the climate atlas of croatia (zaninović et al., 2008), the climate of the slavonski brod area is characterized as a temperate continental climate, with harsh winters, short springs, and warm and humid summers. based on a 30 year measurement period (1971–2000), and data recorded at the meteorological station „slavonski brod“, in the study area the average annual air temperature is 10.7 °c. average monthly temperatures rise until july when they reach a maximum of 21.0 °c. the avera ge annual amount of precipitation is 748.1 mm. concerning the annual course of monthly precipitation, the main maximum occurs in july, and the main minimum in february. still, certain years show a significant deviation in monthly amounts from the average precipitation conditions. based on geomorphological regionalization (bognar, 2001), the study area belongs to the mega-macro-geomorphological region of the pannonian basin, within which the hills of dilj mt. as a micro-geomorphological region stands out. in the study area, the elevation ranges from 94 m to 353 m, and most of the area (almost 73 %) is within the elevation class of 100-200 m (fig. 1c). the elevation class of 300-350 m represents less than 1 % of the study area. the slopes vary from gentle to steep, up to 83°. the southern slopes of dilj mt. are very branched, expanding into a dense network of numerous gullies and valleys. pediments and hills are formed by slope and fluvial-denudation processes (bognar, 1996). according to the area zonation by the degree of stability, on the engineering geological map of sfry in a scale of 1:500.000 (čubrilović et al., 1967) a large part of the study area is defined as a “prevailing unstable area under natural conditions and under the man’s activity mostly unstable”. 2.2. geological setting in the investigated area eight gus are recognized and distinguished (fig. 2): gu1 – limestones and marls (badenian); gu2 – clayey limestones and marls (early-late pannonian); gu3 – marls with sandy interlayers (late pannonian); gu4 – sands with silts and gravel interlayers (late pannonian); gu5 – clay, sands, gravel, and coal (pliocene); gu6 – loess (pleistocene); gu7 – deluvial sediments (holocene); and gu8 – alluvial gravel, sands, and clay (holocene). gu1 – limestones and marls (badenian) are located in the northwestern part of the study area. marls are structureless and contain lower badenian (orbulina universa, o. suturalis, globigerinoides bisphaericus, globoquadrina altispira, and uvigerina macrocarinata), and upper badenian (uvgerina venusta venusta, u. venusta liesigensis, bolivina dilatata, and bulimina pyrula) planktonic and benthic foraminifera (šparica et al., 1979b). limestones contain algal fragments (lithothamnium), and mollusc shells (pecten fuchsi stiryacus, chlamys auensis zollikoferi and osrea sp. šparica et al., 1979b). marls (vejalnica fm.) represent suspension deposits of the offshore (avanić et al., 2018a, b). limestones with lithothamnium algae and mollusc shells indicate the nearshore environment of the vrapče fm. (avanić et al., 2018a, b). gu2 – clayey limestones and marls (early-late pannonian) are located in the northwestern part of the investigated area. they unconformably overlie badenian limestones and marls showing an erosional contact. clayey limestones contain typical macrofossils including radix croatica, limnea extensa, and gyraulus praeponticus (šparica et al., 1979b), while the marls are characterized by the ostracods hungarocypris auriculata, h. hierogliphica, and cyprideis heterostygma obesa (šparica et al., 1979b). clayey limestones were deposited in the littoral area (croatica fm.), and marls are deposited in the deeper part of the lake (medvedski breg fm.) (kovačić et al., 2011; filjak et al., 2016; avanić et al., 2018a, b). gu3 – marls with sandy interlayers (late pannonian) are located in the northern part of the study area and continuously overlie the lower-upper pannonian marls. a rich mollusc and ostracod fauna was recognized within these sediments (paradacna abichi, p. lenzi, didacna otiophora, congeria digitifera, c. zagrabiensis, amplocypris recitulata, candona (caspiocypris) alta, c. (caspiocypris) labiata, c. (camtocypria) balcanica, hemicytheria pejinovicensis, h. marginata, and p. croatica) (šparica et al. 1979b, 1987). marls with sandy interlayers of the andraševec fm. (filjak et al., 2016), were deposited in the prodelta environment (kovačić et al., 2011; avanić et al., 2018a, b). gu4 – sands with silts and gravel interlayers (late pannonian) are situated in the central part of the studied area and continuously overlie the marls with sandy interlayers. these sediments contain a rich macrofauna (congeria rhomboidea, c. markovići, dreissensia auricularis, limnocardium petersi, l. (euximicardium) ocetophorum, didacna otiophora, paradacna okrugići) (šparica et al., 1979b, 1987). sands with silts and gravel interlayers (late pannonian) can be identified within the nova gradiška fm. (filjak et al., 2016), and were deposited in the delta front environment (kovačić et al., 2011; avanić et al., 2018a, b). gu5 – clay, sands, gravel, and coal (pliocene) are located in the southern part of the study area, and unconformably overlie sands with silts and gravel interlayers. the deposits are represented by a typical mollusc assemblage (viviparus bifracinatus, v. dezmanianus, v. hoernesi, v. sturi, v. oncoforus, v. noihus, v. ornatus, v. neumayeri, v. avelanus, v. stricturatus, v. sadleri, melanopsis hastata, m. hybostoma, m. pterochilia, and unio sturzae) (šparica et al., 1979b). gravel and sands are characteristic for alluvial deposits, and clay and coal accumulated in swamps, which can be identified as the vrbova fm. (avanić et al., 2018a, b). gu6 – loess (pleistocene) extends along the southern boundary of the investigated area and overlies pliocene sediments. its granulometric composition is dominated by silt (5070%), with up to 30% sand and clay (šparica et al., 1979b). it contains the typical loess malaco-fauna (trichia hispida, succinea oblonga, pupilla muscorum, p. sterri, vallonia tenuilabris, v. enniensis, and arianta arbustorum) (šparica et al., 1979b, 1987). pleistocene loess is aeolian sediment. gu7 – deluvial sediments (holocene) are located in the northeastern part of the study area and are mostly redeposited marls with sandy interlayers, formed after a short period of transport (šparica et al., 1987). gu8 – alluvial sediments (holocene) fill the stream valleys in the central and northeastern parts of the area and are composed of gravel, sand, and silt. these deposits originate from older sediments of the area, from the badenian to the pleistocene. based on the described gus a simplified evolution of the study area can be proposed. during the badenian in the deeper marine part (offshore) marls (vejalnica fm.), and in the shallow nearshore part lithothamnia limestones (vrapče fm.) were deposited. in the area of dilj mt. the sarmatian is characterized by marine sedimentation in an environment with reduced salinity (dolje fm.). in contrast to the northern part of the dilj mt., in the study area, no sedimentation occurred during the sarmatian. this g eo lo gi a c ro at ic a 6 geologia croatica 75/1 is probably due to local tectonics during that time. later, due to the early pannonian transgression, clayey limestones of the littoral environment begin to accumulate, followed by the early and late pannonian marls of the medvedski breg fm. the marls were deposited in a relatively deeper part of the newly formed brackish pannonia lake (avanić et al., 2018a, b). during the late pannonian, marls with sandy interlayers accumulated in the prodelta environment (andraševec fm.), and sands with layers of silt and gravel of the delta front (nova gradiška fm.), and during the pliocene, sands, gravels, clays, and coals related to rivers and swamps. sedimentation from the lower to the upper pannonian has characteristics of a transgressive sequence, and from the late pannonian to the pliocene of a regressive sequence. in the transgressive sequence, there was a deepening from the littoral to the lake basin, and in the regressive sequence, there was a shallowing or propagation of the river clastic system, when after the lake sediments, the deposits of prodelta, delta-front, alluvial, and swamp plains accumulated. the final terrestrial sedimentation occurred during the quaternary and is represented mostly by loess, as well as by deluvial and alluvial sediments. 3. materials and methods 3.1. input data the hr dtm used in this study is a result of an als, which was performed in the early spring of 2018 by slovenian company flycom technologies d.o.o., fulfilling the requirements for at least 20 points per square meter and assuring the accuracy for each point of at most 10 cm in all directions. as a final product of raw lidar data post-processing, dtm with a 0.5 m resolution is obtained. at the same time, topographic scanning was performed resulting in hr orthophotos with a 10 cm resolution. based on geological reconnaissance and existing basic geological maps (šparica et al., 1979a; šparica, 1986), a geological map of the investigated area was compiled and individual gus (filjak et al., 2016) were interpreted. 3.2. landslide mapping noticeable morphological signs that remain after landslide occurrence can be recognized and mapped through the interpretation of digital topographic surface model (guzzetti et al., 2012). the methodological approach for landslide recognition is based on visual interpretation and geomorphic feature extraction (scaioni et al., 2014) using hr lidar dtm derivatives. for that purpose, several dtm derivatives most commonly used for landslide inventory preparation were extracted, using standard arcgis tools. these are: (i) hillshade maps (according to schulz (2004) different sun azimuth angles of 315°, 135°, and 45°, and a constant altitude angle of 45° were used); (ii) slope map; (iii) profile curvature map; (iv) contour line map with elevation equidistance of 1 m (fig. 3). dtm derivatives were used individually or in combination to delineate landslide polygons. indifigure 2. geological map of the study area modified according to 1:100,000 scale basic geological maps (šparica et al., 1979a; šparica, 1986), with landslide inventory. g eologia c roatica 7bostjančić et al.: spatial distribution and geometric characteristics of landslides with special reference to geological units in the area of slavonski brod vidual landslides are identified and digitized as polygons at a large scale close to 1:500, comprising the completely affected area from the landslide crown to the toe. when more different landslide generations were recognized, each landslide polygon was delineated separately whenever possible in order to obtain the real and representative landslide geometric characteristics. as most of the study area is covered with forest, the use of orthophotos was limited, although in some locations the landslide main characteristics were clearly recognized (e.g., main scarp, crown cracks, flank scarps) (fig. 4). all these morphological signs are generally sharper, better developed and more clearly visible for recently active landslides and are modified through time by different processes of weathering, erosion, and deposition (mccalpin, 1984). as the landslide ages, the more its morphology is reshaped and the less recognisable the landslide features become in the field (mccalpin, 1984; keaton & degraff, 1996; bell et al., 2012; petschko et al., 2014). thus, the recognition of typical landslide characteristics is evaluated by several authors titled as landslide freshness (van den eeckhaut et al., 2007), confidence (burns & madin, 2009), certainty of mapping (petschko et al., 2016), or certainty of landslide identification (bernat gazibara et al., 2019). in this study, the landslide outline confidence level (locl) is presented as the degree of landslide contour certainty based on the visibility and expressiveness of the landslide main features and is expressed with scores from 1 to 10. each of the following landslide features is rated with a confidence score from zero to two: (i) main scarp, (ii) lateral flanks, (iii) toe, (iv) internal landslide morphology (e.g. hummocky or undulating topography, internal cracks, minor scarps), and (v) the ability of discernment of depletion and accumulation areas. based on the confidence scores, four locl classes are defined (tab. 1). a landslide inventory was produced as the basis for the analysis of landslide spatial distribution and geometric characteristics. all of the analyses were performed for landslides with a confidence score higher than two, i.e., for locl classes ii, iii, and iv. in addition, the minimum landslide area for mapping was set to figure 3. examples of landslide polygon delineation for high landslide outline confidence level (a) and moderate landslide outline confidence level (b), using dtm derivatives: contour line map over the hillshade map (a); hillshade map with the transparency of 60 % over the slope map (b); hillshade map with the transparency of 60 % over the profile curvature map (c); landslide polygon on the hillshade map with movement direction (d). figure 4. visibility of landslide characteristics on hr orthophotos: landslide main scarp with several minor scarps (a); landslide main scarp and crown cracks (b). table 1. description of landslide outline confidence level (locl). locl class confidence score description i 1-2 possible landslides with questionable delineated boundaries ii 3-4 landslides with unreliable delineated boundaries in some parts iii 5-7 landslides with imprecise delineated boundaries in some parts iv 8-10 landslides with high precise delineated boundaries g eo lo gi a c ro at ic a 8 geologia croatica 75/1 50 m2, given the scale of the input dtm. in the analysis performed, no distinction was made between the different landslide types, or according to their depth and relative ages. the lidar-based landslide inventory was verified during a field engineering geological inspection, conducted in march 2019. 3.3. landslide inventory analysis preliminary analysis of the landslide inventory was performed, which aimed to define landslide size, shape, and spatial distribution in the study area. geometric parameters used to analyse landslide size and shape are presented for every landslide polygon with several features that were determined automatically (area), and manually (length, width) using standard arcgis tools, or calculated by equation (aspect ratio). based on the landslide area (expressed in square metres), landslides were grouped into five classes (šestanović, 2001): very small (<100), small (100-1,000), moderate (1,000-10,000), large (10,000-50,000), and very large (>50,000). the landslide aspect ratio (la) represents the ratio of landslide length to width. according to the classification based on the landslide aspect ratios proposed by tian et al. (2017), landslides were grouped into four classes: transverse (la≤0.8), isometric (0.8<la≤1.2), longitudinal (1.2<la≤3), and elongated (la>3). the relationship between gus and landslide occurrence within the study area is evaluated and represented by the landslide index. the landslide index, expressed in percentages, is calculated as a ratio between landslide area in a given gu and the area of that unit. the landslide index of each gu is compared to the landslide index of the entire study area, also expressed in percentages and calculated as a ratio between the total landslide area and total study area (bartelletti et al., 2017). in terms of statistics, the correlation between landslides and morphometric parameters (slope, relief, distance to streams) of two major gus (fig. 2) is examined and expressed through landslide density for each parameter class. individual landslide density for each parameter class is compared to the landslide density of each gu, which is calculated as a ratio between landslide number within an individual gu and an area of that unit. for that purpose, centroids of landslide polygons are created. the slope angle was automatically derived from dtm resampled to 5 m resolution. in order to observe landslide distribution from the slope angle perspective, the terrain was classified according to demek (1972), whose classification is based on the dominant processes that activate on a slope of a particular angle. six slope classes (expressed in degrees) are used: 0-2 (plain terrain), 3-5 (slightly sloping terrain), 6-12 (sloping terrain), 13-32 (very sloping terrain), 33-55 (very steep terrain), and > 55 (cliff). relief is expressed as a difference between the maximum and minimum elevation in a certain area and is calculated using the arcgis tool focal statistics. the radius of the circle taken around each cell to calculate the elevation range is set to 250 cells, i.e., 125 m. the six classes (expressed in metres) are defined automatically using natural breaks and are: 0-18 (flattened area), 19-34 (very low relief), 35-47 (low relief), 48-60 (moderate relief), 61-75 (high relief), and 76-109 (very high relief). to calculate the distance to streams, a detailed stream network was automatically extracted from the dtm resampled to 5 m resolution, using the arc hydro tools (v2.0). the standard procedure included filling sinks, computing the flow direction, and flow accumulation. stream definition is based on a flow accumulation and a specified threshold value, which represents the number of cells indicating the start of a stream. the different threshold areas were tested and a representative network was chosen based on visually cross-checking the main streams using a topographic map at a scale of 1:25,000. however, strong topographic diversity influenced the selection of different threshold areas that are associated with the various gus. the stream order was automatically calculated using the method proposed by strahler (1956). a distance to stream map is created as buffer zones around streams and is classified into six classes (expressed in metres): <20, 20-40, 40-60, 60-80, 80-100, and >100. the landslide inventory and spatial analysis were performed using esri arcgis 10.2. the official croatian coordinate projection, htrs96/tm, is used for all maps presented herein. the visualization of graphs was aided by daniel’s xl toolbox add-in for excel, version 7.3.2 (kraus, 2014). 4. results 4.1. landslide inventory in the study area, a total of 854 landslide polygons were delineated, corresponding to an average landslide density of 15.5 landslides per square kilometre. the total mapped landslide area is 0.72 km2 (tab. 2), which represents 1.31 % of the total area. the boundaries for three landslides exceed the study area, but the polygons are completely delineated within the dtm buffer zone, and their actual sizes are used for landslide area statistics. thus, the total study area affected by landslides is, therefore, smaller by 0.004 km2. the landslide areas range from 50.43 m2 to 17,855.32 m2, with an average value of 838.93 m2 (tab. 2). the distribution of landslide area is presented in more detail via the frequency density and a cumulative number of landslides (fig. 5). it is shown that 3.5 % of landslides are smaller than 100 m2, and 20.5 % are larger than 1,000 m2. most landslides (76 %) range between 100 m2 and 1,000 m2, of which 54.4 % are in the range of 100 m2 to 500 m2. within this range, the highest frequency density of 1.48 m2 is presented for landslide areas ranging from 200 m2 to 300 m2. only five landslides are larger than 10,000 m2. considering different classes of locl, the number of landslides decreases as locl increases (tab. 2). thus, almost 60 % of landslides mapped are described with the locl class of ii, and a little over 40 % of landslides with locl class of either iii or iv. as locl gives an overview of the expression of landslide features, these results show that in the study area, all typical landtable 2. statistics of landslide size in the study area, considering different landslide outline confidence level (locl). locl (confidence score) ii (3, 4) iii (5, 6, 7) iv (8, 9, 10) all landslides (3-10) no. of landslides (#) 501 327 26 854 no. of landslides (%) 58.67 38.29 3.04 100.00 landslide density (#/km2) 9.10 5.94 0.47 15.50 landslide area (m2) 286,486.50 358,124.49 71,832.25 716,443.24 smallest landslide area (m2) 50.43 69.86 374.03 50.43 largest landslide area (m2) 12,878.26 17,855.32 15,618.94 17,855.32 average landslide area (m2) 571.83 1,095.18 2,762.78 838.93 median landslide area (m2) 322.36 552.91 1,451.41 408.48 g eologia c roatica 9bostjančić et al.: spatial distribution and geometric characteristics of landslides with special reference to geological units in the area of slavonski brod slide features are not completely visible for most of the landslides (60 %) and the boundaries are particularly hard to determine unambiguously. it can be interpreted as either landslide activation occurred a long time previously explaining why their sharp boundaries and morphological signs have been masked over time, or the landslides are younger but their main features are lost due to fast and strong erosion processes. in addition, the average landslide area increases as locl increases (tab. 2), which is especially a result of a great variability of the smallest landslides within each locl class (the smallest landslide for locl iv is almost 7.5 times larger than the smallest landslide for locl ii). the landslide inventory is verified in the field by checking delineated polygons and identifying the morphological features typical of landslides. the verification is conducted for landslides with different confidence scores (from 3 to 8), and a range of areas between approximately 70 m2 and 7,600 m2, covering the area within three different gus (gu3, gu4, and gu5). from 97 landslides visited, 94 were verified, which represents 11 % of the lidar-mapped landslides. the remaining three landslides are all located in the forest and are marked with locl of ii, i.e. confidence score of 3, but in the field, typical landslide morphology was not confirmed. 4.2. landslides and geological units it is recognized in many landslide studies that the geological setting greatly influences landslide occurrence. as one of the main predisposing environmental factors, geological data are used as one of the main input layers in landslide susceptibility assessment (van westen et al., 2008). thus, for the landslide spatial distribution analysis, first, the relationship between landslide occurrence and gus is investigated. the relationship is expressed with the landslide index (fig. 6), and the landslide statistics for each gu are presented (tab. 3). the landslide index of each gu was compared to the landslide index of the entire study area (bartelleti et al., 2017), enabling determination of which units are more correlated to landslide source areas. considering the landslide area distribution for different gus, it can be seen that landslides are mainly concentrated within gu4 and gu5, where 85 % of landslides are present (fig. 6). within gu4, 423 landslide polygons are delineated, and within gu5, 303 landslide polygons, which corresponds to landslide densities of 31.66 and 18.73 landslides per km2, respectively. these gus refer to late pannonian sands with silts and gravel interlayers (gu4) and pliocene clay, sands, gravels, and coal (gu5). the landslide index in these units is higher than the landslide index of the study figure 5. frequency density and cumulative number of landslides considering landslide area. figure 6. landslide area distribution in different geological units (gu1 – limestones and marls (badenian); gu2 – clayey limestones and marls (early late pannonian); gu3 – marls with sandy interlayers (late pannonian); gu4 – sands with silts and gravel interlayers (late pannonian); gu5 – clay, sands, gravels, and coal (pliocene); gu6 – loes (pleistocene); gu7 – deluvial sediments (holocene); gu8 – alluvial gravels, sands, and clay holocene). the landslide index for each geological unit and for the study area is presented. g eo lo gi a c ro at ic a 10 geologia croatica 75/1 area (1.30 %) at 2.03 % and 2.11 %, respectively. at the same time, as already previously stated, these units are most represented in the study area, covering almost 30 km2 (54 % of the study area). however, the highest landslide index (4,13 %) is calculated for gu1 (badenian limestones and marls), representing only 21 landslides. consequently, the area covered by gu1 is only 0.6 % of the study area. for all other gus, the landslide index is less than 1, i.e., below the landslide index of the study area (tab. 3). according to the average landslide area, the largest landslides occur in gu5, and the smallest in gu4 (tab. 3). the differences in landslide average width are not so noticeable, with values ranging from 20.05 m to 25.61 m. the values of landslide average length, compared to others, for gu5 and gu6 stands out, with values of 51.55 m and 51.86 m, respectively. 4.3. landslides within the predominant geological units 4.3.1. morphometric analysis the diversity of gu4 and gu5 environments is represented by their morphometric features, including slope angle, relief, and drainage network (fig. 7). although the range and average values of the slope angles within gu4 and gu5 are similar, the slope angle class distribution shows differences (fig. 7a). almost 90 % of the area of gu4 is within three classes in the range of 6° to 55°, with the most representative class of 13-32° (54 %). most of the area of gu5, almost 95 %, is within three classes in the range of 3° to 32°, with the most representative class of 6-12° (49 %). slope angle class with values above 55° is the least represented, with an area below 1 % for both gus. the values of relief for gu4 and gu5 range from 5 m to 109 m, and from 9 m to 100 m, respectively (tab. 4). for gu4, 81 % of the area is within three relief classes in the range of 48 m to 109 m, with the most representative class of 61-75 m (34 %). for gu5, 87 % of the area is within three relief classes in the range of 19 m to 60 m, with the most representative class of 35-47 m (44 %). for both gus the relief class with values below 19 m is least represented covering approx. 1 % in both gus (fig. 7b). concerning the classes defined to analyse the distance to streams, 65 % of the area of gu4 is within the first three classes, with distances to streams less than 60 m. within this unit, most of the area (25 %) is in the stream buffer zone of 0-20 m. for gu5, all classes are almost equally represented, with significant representation by class (43 %) where the distance to stream is more than 100 m (fig. 7c). these results indirectly indicate that the stream network within gu4 is more branched and denser than within gu5. this is also shown by the results of the analysis of stream length for different stream orders (tab. 4). since the lidar polygon does not include the entire basin, only streams that are completely developed (streams of a certain order and all lower orders) in a single gu, are considered. there are half as many 1st order streams within gu4 than gu5, although the total length of 1st order streams does not differ much between these two units. consequently, there is a big difference in their average stream lengths, 87.70 m within gu4 and 164.06 m within gu5. thus, gu4 can be described as a unit with a short but dense series of 1st order streams, and gu5 as a unit where 1st order streams are rarer but much longer. the same trend is presented for 2nd order streams. furthermore, the difference in the stream number and stream lengths decreases for 3rd order streams, and is even less for 4th order streams. 4.3.2. landslide spatial distribution in two zones characterized by different geological and geomorphological conditions, landslide spatial distribution is analysed. classes of parameters that create favourable preconditions to slope instability, presented in the previous sub-chapter, are defined based on landslide density (fig. 8). considering the slope angle, landslides within gu4 are mainly concentrated within classes of 13-32° (52 % landslides) and 33-55° (45 % landslides). the highest landslide density is also related to these classes, with the highest peak of 115 landslides per km2 within the class of 33-55° (fig. 8a). within gu5, a large number of landslides is also related to classes of 13-32° (64 % landslides) and 33-55° (12 % landslides). still, landslides are also concentrated on somewhat milder slopes, within a class of 6-12° (23 % landslides). the highest landslide density is related to the class of 33-55°, with 79 landslides per km2 (fig. 8a), same as for gu4. the differences in the relationship between slope angle and table 3. landslide statistics for each geological unit. geological unit 1 2 3 4 5 6 7 8 no of landslides 21 39 38 423 303 7 0 23 no of landslides (%) 2.46 4.57 4.45 49.53 35.48 0.82 2.69 no of landslides locl ii 11 26 21 271 157 2 13 no of landslides locl iii 10 13 17 142 130 5 10 no of landslides locl iv 0 0 0 10 16 0 0 landslide index 4.13 0.95 0.34 2.03 2.11 0.18 0.25 landslide density (# / km2) 61.93 11.80 4.30 31.66 18.73 2.01 2.69 average landslide area (m2) 667.53 802.74 793.41 642.24 1,127.97 883.18 927.88 average landslide length (m) 31.90 35. 33 31.50 34.10 51.55 51.86 39.39 average landslide width (m) 24.95 24.26 25.61 20.05 22.77 22.14 22.13 table 4. number and length of streams considering different stream orders within geological units 4 and 5. geological unit stream order no of streams analysed total stream length (m) average stream length (m) 4 1 380 33327.74 87.70 2 69 6258.184 90.70 3 11 739.37 67.22 4 2 115.51 57.75 5 1 183 30022.92 164.06 2 39 6773.36 173.68 3 8 574.84 71.85 4 1 134.70 134.7 g eologia c roatica 11bostjančić et al.: spatial distribution and geometric characteristics of landslides with special reference to geological units in the area of slavonski brod figure 7. spatial distribution of parameters’ classes within geological units 4 and 5, concerning: slope (a); relief (b); and distance to streams (c). g eo lo gi a c ro at ic a 12 geologia croatica 75/1 landslide occurrence can be expressed by the average values of slope angle within landslide polygons and the rest of the area. thus, for gu4 the average slope angle within areas affected by landslides is 27°, and for gu5 is 18°. for the area not affected by landslides, the average slope angle for gu4 is 17° and gu5 is 12°. in a view of relief, 96 % of landslides within gu4 are concentrated within classes with relief values higher than 48 m, with the highest concentration within the class of 61-75 m (45 % landslides). the highest landslide density is also related to these classes (fig. 8b). within gu5, the highest landslide concentration is related to classes with relief values from 35 m to 75 m (64 % landslides). the highest landslide density is, however related to the class of >76 m (fig. 8b). the differences in the relationship between relief and landslide occurrence expressed by the average values of relief within landslide polygons and the rest of the area are more significant compared to the slope angle. for gu4 the average relief within areas affected by landslides is 65 m, and for gu5 it is 51 m. for the area not affected by landslides, the average relief for gu4 is 61 m and for gu5 it is 45 m. considering the distance to streams, 92 % of landslides within gu4 are concentrated within the classes 0-20 m (62 % landslides) and 20-40 m (30 % landslides). the highest landslide density is also related to these classes, with the highest peak of 78 landslides per km2 within the class of 0-20 m (fig. 8c). within gu5, 81 % of landslides are concentrated within classes with a distance below 60 m. still, the highest landslide density is related to the class of 0-20 m, with a value of 52.6 landslides per km2 (fig. 8c). 4.3.3. landslide geometric characteristics several landslide characteristics are considered, including area, length, width, and aspect ratio (table 5), in order to compare landslide size and shape within gu4 and gu5. comparing landslide sizes, the average landslide area in gu4 (642.24 m2) is almost half the size of the average landslide area in gu5 (1,127.97 m2). the range of landslide areas within gu4 and gu5 is quite different (see box plots, fig. 9a) though the outliers are not represented, thus the maximum landslide areas are not shown. the difference in landslide width is not as significant as landslide length, as was the case with the analysis of landslide inventory for each gu (tab. 3). the average landslide lengths for gu4 figure 8. landslides and landslide density (number of landslides per area of each parameter class) for geological units 4 and 5, concerning: slope angle (a); relative relief (b); and distance to streams (c). landslide density for each geological unit (number of landslides per area of the geological unit) is also presented. g eologia c roatica 13bostjančić et al.: spatial distribution and geometric characteristics of landslides with special reference to geological units in the area of slavonski brod and gu5 are 34.10 m and 51.55 m, respectively (tab. 5). this difference influences not only the landslide area but also the landslide shape. the average aspect ratio is thus slightly larger for landslides within gu5. the average aspect ratio for gu4 and gu5 is 1.88 and 2.27, respectively (tab. 5). the aspect ratio classes indicate that for both gus most landslides occur within two classes and landslides are mainly longitudinal. further, it can be stated that an isometric shape is more associated with landslides within gu4 and an elongated shape with landslides within gu5 (fig. 9b). 5. discussion landslide inventories are the basis for assessing landslide susceptibility, hazard, and risk assessment (soeters & van westen, 1996; van westen et al., 2008). without knowledge about landslide locations, the methods for susceptibility models that predict landslides based on past conditions remain inapplicable. the landslide inventory accomplished for the study area includes landslides that occur over time (periods of tens, hundreds, or even more years), and are not associated with a trigger event. thus, this inventory can be interpreted as a historical geomorphological inventory (malamud et al., 2004; guzzetti et al., 2012). the landslide inventories are widely used to analyse landslide statistics, including their size, shape, and location (malamud et al., 2004). considering the landslide size and shape, geometricl parameters and their ratios can be further analysed to characterize landslides and assess their volumes, motion mechanisms, runout distances, and hazard (tian et al., 2017). considering the landslide distribution, it has been proven that landslides mostly occur at preferred locations. among others, geologicallithological and morphometric parameters have been used as the main environmental predisposing factors to analyse the effects on landslide spatial distribution (van westen et al., 2008; reichenbach et al., 2018). the distribution of landslides concerning the main factors controlling shallow landslides (lithotype, regolith thickness, slope angle, and land use) is discussed for the picentino river basin in southern italy (lupiano et al., 2019). conforti & ietto (2020) highlighted that the lithology, fault density, slope gradient, and relief have an important role in determining landslide occurrence. guzzetti et al. (2008) examined the relationship between landslide distribution and local morphological and lithological settings, in the upper tiber river basin in central italy. their analysis confirmed that geological conditions influence the abundance of landslides in the catchment. jacobs et al. (2016) also concluded that landslide processes largely depend on the prevailing lithology. in their study, slope angle is distinguished as the main controlling topographic factor for landslides. bartelletti et al. (2017) investigated the influence of geological-morphological and land use settings on the occurrence of shallow landslides. they used the landslide index to identify significant parameters correlated with landslide source areas. in lithologically homogeneous areas, (as each of the presented gus may be considered), coco & buccolini (2015) indicated that the slope morphometry, especially angle, height, and form were the most influential factors on landslide occurrence. they also confirm that landslides are coupled with a drainage network. in this study, the geological setting is proven to be the significant influencing factor that controls landslide occurrence and abundance. besides analysing the number of landslides within individual gus, the correlation between gus and landslide occurrence is estimated and expressed with the landslide index. the highest landslide index is defined for the unit represented by the badenian limestones and marls (gu1). since the area covered by gu1 represents only 0.6 % of the study area where only 21 landslides are mapped, further investigations are needed in areas where this unit is much more representative. the next two units for which the landslide index is above the landslide index of the study area refer to late pannonian sands with silts and gravel interlayers (gu4) and pliocene clay, sands, gravels, and coal (gu5). as 85 % of the mapped landslides are concentrated within these units, they can be considered to be the most susceptible to landslide processes in the study area. when taken into consideration the uniform geographical, climatic, and tectonic settings for gu4 and gu5, it can be reasonably assumed that the geological setting is the prevailing factor in the evolution of this area. significant differences in morphometric features are strongly correlated to the geological table 5. descriptive statistics for landslide characteristics for geological units 4 and 5. parameter geological unit min max average median area (m2) 4 50.77 17,855.32 642.24 368.40 5 63.14 15,618.94 1,127.97 475.36 length (m) 4 9.00 233.00 34.10 30.00 5 8.00 375.00 51.55 37.00 width (m) 4 6.00 115.00 20.05 16.00 5 6.00 101.00 22.77 19.00 aspect ratio 4 0.48 4.71 1.88 1.78 5 0.40 8.90 2.27 2.09 figure 9. area (a) and aspect ratio (b) for landslides within geological units 4 and 5. g eo lo gi a c ro at ic a 14 geologia croatica 75/1 setting, i.e. lithological features and material characteristics, which are clearly visible on fig. 7. still, it is necessary to emphasize the scale of the input of geological data (basic geological map in scale 1:100,000), which may affect the presented results in the boundary areas of gus. this can also explain the fact that 2.69 % of landslides is placed within gu8 (alluvial gravel, sands, and clay), as presented in table 3. the unified results of detailed analysis performed for gu4 and gu5, elaborating the relationship between morphometric features and landslide source areas, and geometrical characteristics of landslides, are presented in table 6. observing the classes of morphometric parameters analysed, it is evident that the predominant classes for slope and relief within these two units differ for one to two class categories (tab. 6). considering the distance to streams, the dominant classes differ even more. significant morphometric characteristics within gu4 refer to high relief, steep slopes, the dense stream network, and branched gullies. dominant distance from stream classes are less than 60 m. morphometric characteristics within gu5 refer to low relief, less steep slopes, and a less dense stream network, when compared to gu4, with dominant distance from stream classes greater than 100 m. regardless of these differences, parameters’ classes defined as the most influenced on landslide spatial distribution are almost equal for both of these units. the classes for which the landslide density of parameter class is higher or very close to the landslide density of the entire gu are singled out. based on these results, landslides are predominantly occurring on very steep and very sloping terrain, with very high, high, and moderate relief, and are strongly coupled to streams (tab. 6). the fluvial-denudation processes, together with slope processes have the dominant influence on the development of local landscape. the geomechanical properties of sands are a dominant factor for current landscape formation in gu4. their drainage capabilities and low cohesion causes the development of a dense gully network due to strong erosion processes. consequently, the majority of the landslides are associated with the steep gully banks. typical landslides are small and shallow, often without clearly visible landslide elements in the foot area where the landslide material is removed by permanent or intermittent streams. in contrast to gu4, low drainage properties of gu5 govern landscape shapes in their respective area, where the soil complex comprises impermeable clay interlayers or lenses. landslides are predominantly triggered by high groundwater pore pressures. landslides are slightly larger and more elongated, when compared to landslides within gu4, which implies the flow of material when the landslide is activated. the differences in landslide geometric characteristics within these units implies that geological characteristics and consequent morphometric features influence not only the landslide density and spatial distribution but also the landslide size and shape. 6. conclusion in this paper, preliminary analysis of the initial lidar-based landslide inventory for the area of slavonski brod is presented for the first time. using hr lidar dtm derivatives (hillshade, slope, curvature, and contour line maps), the geomorphological historical landslide inventory for an area of 55.1 km2 was completed. in total, 854 landslide polygons were delineated, corresponding to an average landslide density of 15.5 landslides per square kilometre. the landslide area ranges from 50.43 m2 to 17,855.32 m2, with an average value of 838.93 m2, according to which they can be considered as small landslides. given the strong relationship between landslide occurrence and geological setting in many studies, first, the spatial landslide distribution was evaluated, according to eight gus defined in the study area. the correlation between gus and landslide occurrence is estimated and expressed with the landslide index. according to differences in the landslide index, the geological setting can be considered as a significant feature in landslide susceptibility assessment. late pannonian sands with silts and gravel interlayers (gu4) and pliocene clay, sands, gravels, and coal (gu5) are those units where the majority of landslides are concentrated. 85 % of landslide polygons mapped are present within these units. besides, these units are predominantly represented in the study area, covering an area of almost 30 km2. the landslide index for both of these units is above the landslide index of the study area. according to all the above, gu4 and gu5 were chosen for detailed investigation, in order to analyse the landslide spatial distribution and compare landslide geometrical characteristics. defining the relationship between landslide distribution and environmental parameters enables a better understanding of landslide characteristics and occurrence, and can help to predict the future landslides. parameters analysed in this study (slope, relief, and distance to stream) are proven to influence landslide spatial distribution, and classes with a stronger correlation with landslide density are defined. table 6. main morphometric and landslide characteristics within geological units 4 and 5. geological unit late pannonian sands with silts and gravel interlayers (gu4) pliocene clay, sands, gravels, and coal (gu5) main morphometric characteristics – sloping to very steep terrain (dominant class of 13-32°) – moderate to very high relief (dominant class of 61-75 m) – dense stream network with large number of 1st order streams (average length of 87.70 m) – branched gullies with steep side walls – slightly to very sloping terrain (dominant class of 6-12°) – very low to moderate relief (dominant class of 35-47 m) – rarer stream network with less number of 1st order streams (average length of 164.06 m) – gullies with less steep side walls landslide spatial distribution – landslide density of 31.66 per km2 within entire unit – highest landslide density for very steep (33-55°) and very sloping (13-32°) terrain – highest landslide density for high (61-75 m), very high (76-109 m), and moderate (48-60 m) relief – highest landslide density at a distance of 0-20 m and 20-40 m from streams – landslide density of 18.73 per km2 within entire unit – highest landslide density for very steep (33-55°) and very sloping (13-32°) terrain – highest landslide density for very high (76-109 m), high (61-75 m), and moderate (48-60 m) relief – highest landslide density at a distance of 0-20 m, 20-40 m, and 40-60 m from streams main landslide characteristics – very small to moderate landslide size, according to average area (642.24 m2) small landslides – longitudinal to isometric shape – dominant mapping landslide outline confidence level of ii – very small to large landslide size, according to average area (1,127.97 m2) moderate landslides – longitudinal to elongated shape – dominant mapping landslide outline confidence level of ii and iii g eologia c roatica 15bostjančić et al.: spatial distribution and geometric characteristics of landslides with special reference to geological units in the area of slavonski brod the results of landslide spatial distribution compared to geological features, slope morphometry, and stream network, provide useful information for further studies related to landslide susceptibility and hazard. in that sense, the basic information of significant predisposing factors controlling landslide occurrence in the study area is given. together with the landslide inventory created, a large proportion of relevant input data is prepared. those data are of great importance and can be used to produce statistically-based landslide susceptibility maps and to predict areas of higher landslide susceptibility. it would allow the local authorities to direct detailed engineering geological investigations and financial resources toward landslide-prone areas, highly relevant for the hilly area of slavonski brod. acknowledgement the basis for landslide inventory and all the analysis presented in this study was a high resolution lidar-based digital terrain model. it was obtained within the implementation activities in the framework of the safearth project, which was co-financed by the interreg ipa cross-border cooperation programme croatia – bosnia and herzegovina – montenegro 2014-2020. references ardizzone, f., cardinali, m., galli, m., guzzetti, f. & reichenbach, p. (2007): identification and mapping of recent rainfall-induced landslides using elevation data collected by airbone lidar.– natural hazards and earth system sciences, 7, 637–650. doi: 10.5194/nhess-7-637-2007 avanić, r., kovačić, m., pavelić, d. & peh, z. (2018a): the neogene of hrvatsko zagorje.– in: tibljaš, d., horvat, m., tomašić, n., mileusnić, m. & grizelj, a. (eds.): 9th mid-european clay conference, conference book, field trip guide book, zagreb, 128–129. avanić, r., šimunić, an. & peh, z. (2018b): geology of the croatian zagorje region.– in: rman, n., marković, t. & brenčić, m. (eds.): 5. slovenski geološki kongres, post congress field trip book, ljubljana, 35. bartelletti, c., giannecchini, r., d’amato avanzi, g., galanti, y. & mazzali, a. (2017): the influence of geological–morphological and land use settings on shallow landslides in the pogliaschina t. basin (northern apennines, italy).– journal of maps, 13/2, 142–152. doi: 10.1080/17445647.2017.1279082 bell, f.g. (2003.): geological hazards: their assessment, avoidance and mitigation.– spoon press, london, 648 p. bell, r., petschko, h., röhrs, m. & dix, a. (2012): assessment of landslide age, landslide persistence and human impact using airborne laser scanning digital terrain models.– geografiska annaler: series a, physical geography, 94, 135–156. doi: 10.1111/j.1468‐0459.2012.00454.x bernat gazibara, s., krkač, m. & mihalić arbanas, s. (2019): landslide inventory mapping using lidar data in the city of zagreb (croatia).– journal of maps, 15/2, 773–779. doi: 10.1080/17445647.2019.1671906 bognar, a. (1996): tipovi klizišta u republici hrvatskoj i republici bosni i hercegovini – geomorfološki i geoekološki aspekti. [the main types of landslides in the republic of croatia and republic of bosnia and hercegovina – geomorphological and landscape ecological aspects – in croatian].– acta geographica croatica, 31, 27–39. bognar, a. (2001): geomorfološka regionalizacija hrvatske [geomorphological regionalisation of croatia – in croatian].– acta geographica croatica, 34, 7–29. bpž, brodsko-posavska županija (2019): procjena rizika od velikih nesreća: identifikacija, analiza, vrednovanje i obrada rizika od velikih nesreća za područje brodsko-posavske županije [risk assessment of major accidents: identification, analysis, evaluation, and treatment of the major accident risk in the area of brodposavina county – in croatian]. –brodsko-posavska županija, 301 p. burns, w.j. & madin, i.p. (2009): protocol for inventory mapping of landslide deposits from light detection and ranging (lidar) imagery.– special paper 42, oregon department of geology and mineral industries, 30 p. chacon, j., irigaray, c., fernandez, t. & el hamdouni, r. (2006): engineering geology maps: landslides and geographical information systems.– bulletin of engineering geology and the environment, 65, 341–411. doi: 10.1007/s10064006-0064-z coco, l. & buccolini, m. (2015): the effect of morphometry, land-use and lithology on landslides susceptibility.– in: schweckendiek, t., van tol, a.f., pereboom, d., van staveren, m.th. & cools, p.m.c.b.m. (eds): geotechnical safety and risk v, ios press bv, 779–784. doi: 10.3233/978-161499-580-7-779 conforti, m. & ietto, f. (2020): influence of tectonics and morphometric features on the landslide distribution: a case study from the mesima basin (calabria, south italy).– journal of earth science, 31, 393–409. doi: 10.1007/s12583-0191231-z crozier, m.j. (2010): landslide geomorphology: an argument for recognition, with examples from new zeland.– geomorphology, 120/1–2, 3–15. doi: 10.1016/j.geomorph.2009.09.010 čubrilović, p., palavestrić, lj. & nikolić, t (1967): inženjerskogeološka karta sfr jugoslavije u mjerilu 1:500000 [engineering geological map of sfry in scale 1:500.000 – in croatian].– savezni geološki zavod, beograd. demek, j. & igu (1972): manual of detailed geomorphological mapping.– igu comission on geomorphological survey and mapping, chechoslovak academy of science, prague, 344 p. derron, m.-h. & jaboyedoff, m. (2010): preface “lidar and dem techniques for landslides monitoring and characterization”.– natural hazards and earth system sciences, 10, 1877–1879. doi: 10.5194/nhess-10-1877-2010 fell, r., corominas, j., bonnard, c., cascini, l., leroi, e. & savage, w.z. (2008): guidelines for landslide susceptibility, hazard and risk zoning for land use planning.– engineering geology, 102/3–4, 85–98. doi: 10.1016/j.enggeo.2008.03.022 filjak, r., pikija, m., avanić, r., bakrač, k. & miknić, m. (2016): osnovna geološka karta republike hrvatske mjerila 1 : 50000 – list slavonska požega 4 [basic geological map of republic of croatia 1:50000, slavonska požega 4 sheet – in croatian].– hrvatski geološki institut, zavod za geologiju, zagreb. görüm, t. (2019): landslide recognition and mapping in a mixed forest environment from airborne lidar data.– engineering geology, 258, 105155. doi: 10.1016/j. enggeo.2019.105155 guzzetti, f., ardizzone, f., cardinali, m., galli, m., reichenbach, p. & rossi, m. (2008): distribution of landslides in the upper tiber river basin, central italy.– geomorphology, 96, 105–122. doi: 10.1016/j.geomorph.2007.07.015 guzzetti, f., mondini, a.c., cardinali, m., fiorucci, f., santangelo, m. & chang, k.-t. (2012): landslide inventory maps: new tools for an old problem.– earth-science reviews, 112, 42–66. doi: 10.1016/j.earscirev.2012.02.001 haque, u., blum, p., da silva, p.f., andersen, p., pilz, j., chalov, s.r., malet, j.-p., auflič, m.j., andres, n., poyiadji, e., lamas, p.c., zhang, w., peshevski, i., pétursson, t.k., dobrev, n., garcíadavalillo, j.c., halkia, m., ferri, s., gaprindashvili, g., engström, j. & keellings, d. (2016): fatal landslides in europe.– landslides, 13/6, 1545–1554. doi: 10.1007/s10346-016-0689-3. horváth, f. & royden, l.h. (1981): mechanism for the formation of the intracarpathian basins: a review.– earth-science reviews, 3–4, 307–316. jaboyedoff, m., oppikofer, t., abellán, a., derron, m.-h., loye, a., metzger, r. & pedrazzini, a. (2012): use of lidar in landslide investigations: a review.– natural hazards, 61, 5–28. doi: 10.1007/s11069-010-9634-2 jacobs, l., dewitte, o., poesen, j., maes, j., mertens, k., sekajugo, j. & kervyn, m. (2016): landslide characteristics and spatial distribution in the rwenzori mountains, uganda.– journal of african earth sciences, 134, 917–930. doi: 10.1016/j.jafrearsci.2016.05.013 jagodnik, p., jagodnik, v., arbanas, ž. & mihalić arbanas, ž. (2020): landslide types in the slani potok gully, croatia.– geologia croatica, 73/1, 13–28. doi: 10.4154/gc.2020.04 keaton, j.r. & degraff, j.v. (1996): surface observation and geologic mapping. in: turner, a.k. & schuster, r.l. (eds.): landslides – investigation and mitigation, national research council, washington, dc, 178–230. kovačić, m., horvat, m., pikija, m. & slovenec, da. (2011): composition and provenance of neogene sedimentary rocks of dilj gora mt. (south pannonian basin, croatia).– geologia croatica, 64/2, 121–132. doi: https://doi.org/10.4154/ gc.2011.10 kraus, d. (2014): an open-source add-in for the microsoft excel® spreadsheet software. downloaded from https://www.xltoolbox.net/ (21.09.2020) lupiano, v., rago, v., terranova, o.g. & iovine, g. (2019): landslide inventory and main geomorphological features affecting slope stability in the picentino river basin (campania, southern italy).– journal of maps, 15/2, 131–141. doi: 10.1080/17445647.2018.1563836 malamud, b.d., turcotte, d.l., guzzetti, f. & reichenbach, p. (2004): landslide inventories and their statistical properties.– earth surface processes and landforms, 29, 687–711. doi: 10.1002/esp.1064 mccalpin, j. (1984): preliminary age classification of landslides for inventory mapping.– proceedings of the annual symposium on engineering geology and soil engineering, 21, moscow, idaho, 99–120. mihalić arbanas, s., krkač, m. & bernat, s. (2016): application of advanced technologies in landslide research in the area of the city of zagreb (croatia, europe).– geologia croatica, 69/2, 231–243. doi: 10.4154/gc.2016.18 mihalić arbanas, s., sečanj, m., bernat gazibara, s., krkač, m., begić, h., džino, a., zekan, s. & arbanas, ž. (2017): landslides in the g eo lo gi a c ro at ic a 16 geologia croatica 75/1geologia croatica 74/2 dinarides and pannonian basin – from the largest historical and recent landslides in croatia to catastrophic landslides caused by cyclone tamara (2014) in bosnia and herzegovina.– landslides, 14, 1861–1876. doi: 10.1007/s10346-017-0880-1 pavelić, d. & kovačić, m. (2018): sedimentology and stratigraphy of the neogene rift-type north croatian basin (pannonian basin system, croatia): a review.– marine and petroleum geology, 91, 455–469. doi: 10.1016/j.marpetgeo.2018.01.026 pawluszek, k. (2019): landslide features identification and morphology investigation using high-resolution dem derivatives.– natural hazards, 96, 311–330. doi: 10.1007/s11069-018-3543-1 petschko, h., bell, r. & glade, t. (2014): relative age estimation at landslide mapping on lidar derivatives: revealing the applicability of land cover data in statistical susceptibility modelling.– in: sassa, k., canuti, p. & yin, y. (eds.): landslide science for a safer geoenvironment, springer, 337–343. doi: 10.1007/978-3-319-05050-8_53 petschko, h., bell, r. & glade, t. (2016): effectiveness of visually analyzing lidar dtm derivatives for earth and debris slide inventory mapping for statistical susceptibility modelling.– landslides, 13, 857–872. doi: 10.1007/s10346-0150622-1 reichenbach, p., rossi, m., malamud, b.d., mihir, m. & guzzeti, f. (2018): a review of statistically-based landslide susceptibility models.– earthscience reviews, 180, 60–91. doi: 10.1016/j.earscirev.2018.03.001 royden, l.h. (1988): late cenozoic tectonics of the pannonian basin system.– in: royden, l.h. & horvath, i.f. (eds.): the pannonian basin: a study in basin evolution. aapg memoir, 45, 27–48. doi: 10.1306/m45474c3 scaioni, m., longoni, l., melillo, v. & papini, m. (2014): remote sensing for landslide investigations: an overview of recent achievements and perspectives.– remote sensing, 6/10, 9600–9652. doi: 10.3390/rs6109600 schulz, w.h. (2004): landslides mapped using lidar imagery, seattle, washington. u.s. geological survey open–file report 2004–1396, 11 p. soeters, r. & van westen, c.j. (1996): slope instability recognition, analysis, and zonation.– in: turner, a.k. & schuster, r.l. (eds.): landslides: investigation and mitigation. transportation research board, 247, national academy press: washington dc, 129–177. strahler, a.n. (1956): quantitative slope analysis.– geological society of america bulletin, 67, 571–596. doi: 10.1130/0016-7606(1956)67%5b571:qsa%5d2. 0.co;2 šestanović, s. (2001): osnove geologije i petrografije [fundamentals of geology and petrography – in croatian].– sveučilište u splitu, građevinski fakultet, 236 p. šparica, m., juriša, j., crnko, j., šimunić, an., jovanović, č. & živanović, d. (1979a): osnovna geološka karta sfrj 1:100.000, list nova kapela [basic geological map of sfry 1:100.000, nova kapela sheet – in croatian].– institut za geološka istraživanja, zagreb, geološki zavod, sarajevo, savezni geološki zavod, beograd. šparica, m., juriša, j., crnko, j., šimunić, an., jovanović, č. & živanović, d. (1979b): osnovna geološka karta sfrj 1:100.000. tumač za list nova kapela [basic geological map of sfry 1:100000, geology of the nova kapela sheet – in croatian].– institut za geološka istraživanja, zagreb, geološki zavod, sarajevo, savezni geološki zavod, beograd. šparica, m. (1986): osnovna geološka karta sfrj 1:100.000, list slavonski brod [basic geological map of sfry 1:100.000, slavonski brod sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. šparica, m., buzaljko, r. & mojićević, m. (1987): osnovna geološka karta sfrj 1:100.000. tumač za list slavonski brod [basic geological map of sfry 1:100.000, geology of the nova kapela sheet – in croatian].institut za geološka istraživanja, zagreb, geološki zavod, sarajevo, savezni geološki zavod, beograd. tarolli, p. (2014): high-resolution topography for understanding earth surface processes: opportunities and challenges.– geomorphology, 216, 295–312. doi: 10.1016/j.geomorph.2014.03.008 tian, y., xu, c., chen, j., zhou, q. & shen, l. (2017): geometrical characteristics of earthquake-induced landslides and correlations with control factors: a case study of the 2013 minxian, gansu, china, mw 5.9 event.– landslides, 14, 1915– 1927. doi: 10.1007/s10346-017-0835-6 toševski, a. (2013): inventar klizišta u slivu rijeke dubračine [slide inventory in dubracina river basin – in croatian].– rudarsko-geološko-naftni zbornik, 27, 1–16. van den eeckhaut, m., poesen, j., verstraeten, g., vanacker, v., nyssen, j., moeyersons, j., van beek, l.p.h. & vandekerckhove, l. (2007): use of lidar-derived images for mapping old landslides under forest.– earth surface processes and landforms, 32, 754–769. doi: 10.1002/esp.1417 van westen, c.j. (2000): the modelling of landslide hazards using gis.– surveys in geophysics, 21, 241–255. van westen, c.j., castellanos, e. & kuriakose, s.l. (2008): spatial data for landslide susceptibility, hazard, and vulnerability assessment: an overview.– engineering geology, 102/3–4, 112–131. doi: 10.1016/j.enggeo.2008.03.010 varnes, d.j. & iaeg (1984): landslide hazard zonation: a review of principles and practice.– iaeg commission on landslides and other mass movements, natural hazards 3, unesco, paris, 63 p. zaninović, k., gajić-čapka, m., perčec tadić, m., vučetić, m., milković, j., bajić, a., cindrić, k., cvitan, l., katušin, z., kaučić, d., likso, t., lončar, e., lončar, ž., mihajlović, d., pandžić, k., patarčić, m., srnec, l. & vučetić, v. (2008): klimatski atlas hrvatske: 1961-1990, 1971-2000 [climate atlas of croatia: 1961-1990, 1971-2000 – in croatian].– državni hidrometeorološki zavod, zagreb, 200 p. 2022 | 75/3 | 365–380 | 10 figs. | 3 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society introduction the study area is located close to the villages of hacıbalı, mahmutlar and aşağısamanlık in kırıkkale province, in the central anatolian region (fig. 1). the depositional basins in the central anatolian region formed above two continental units––the sakarya continent and kırşehir block-separated by a suture zone (gorur et al., 1998) (fig. 1). in the late cretaceous, the sakarya continent, menderes–tauride platform and kırşehir block were separated by the i̇zmir–ankara, ankara–erzincan and inner tauride oceans. at the end of the cretaceous, the kırşehir block and sakarya continent collided (tuysuz & dellaloglu, 1992; gorur et al., 1998). the kırşehir block is surrounded by ophiolitic mélanges created as a result of the subduction of the i̇zmir–ankara, ankara–erzincan and, later, the inner tauride oceans (gorur et al., 1998). the kırşehir block, on which the study area is located, comprises mostly ophiolitic rock fragments and sedimentary cover rocks sitting above a metamorphic basement. the basement comprises gneiss, amphibolite, schists and marbles resulting from cretaceous metamorphism (ketin, 1961; erkan, 1975; şengor & yilmaz, 1981; goncuoğlu, 1981; seymen, 1982; şengor, 1985; gorur et al., 1998). the cover rocks above this metamorphic basement extend from the upper cretaceous to the holocene and mostly represent sedimentary sequences filling basins that varied in width and depth (gorur et al., 1998). the calcareous nannofossil record of the uppermost maastrichtian-lower palaeocene in the kırıkkale basin, in the central anatolian region (turkey) caner kaya ozer1,* and yakup kilic2 1 yozgat bozok university, faculty of engineering-architecture, geological engineering department, divanlı road, yozgat, turkey; (*corresponding author: c.kayaozer@gmail.com) 2 yozgat bozok university, graduate education institute, divanlı road, yozgat, turkey doi: 10.4154/gc.2022.30 abstract the late cretaceous–early paleogene (k–pg) was a critical period of transition in geological time. this period encompassed short-term climatic fluctuations on a global scale, changes in ocean circulation, and sudden and large extinctions of marine and terrestrial organisms. in the study area, located in the mid to low latitudes, the late cretaceous and early paleogene were very tectonically active due to the positioning of the site close to the collision zone of two large continents. the impacts of the global k–pg crisis can be observed in the study area. in this study, the calcareous nannofossil contents of late maastrichtian–danian sediments were studied, and the nannofossil biostratigraphy determined, from samples from the samanlık and dizilitaşlar formations, deposited in the kırıkkale basin. from three stratigraphic sections, 26 nannofossil genera and 36 nannofossil species were identified from the late maastrichtian uc20atp and uc20btp biozones and the np1 and np2 biozones of the danian. additionally, it was determined that the k–pg boundary was not continuous in the study area. in the kırıkkale basin, relatively low abundances of micula decussate vekshina, 1959 signals a diagenetic effect and stressful environment in the late maastrichtian, whereas the relatively low abundances of thoracosphaera operculata bramlette & martini, 1964, braarudosphaera bigelowii (gran & braarud, 1935) deflandre, 1947 and futyania petalosa (ellis & lohmann, 1973) varol, 1989 in the danian assemblages indicate unstable environmental conditions and major environmental perturbations that reflect tectonic activity in the region. no nannofossils were encountered in those samples taken from turbiditic levels, which contained high proportions of sand. the kırıkkale basin, which evolved between the late cretaceous and late palaeocene, has several features of a within-arc basin (gorur et al., 1998), and is deep and narrow, forming a connection between the çankırı basin to the north and the tuzgölü basin to the south (norman, 1972a, b; gokcen, 1977). the turbiditic sedimentation in the basin began before the maastrichtian, with abundant volcanic and volcano-sedimentary contributions. gorur et al. (1998) stated that the turbiditic sedimentation lasted until the end of the lutetian and was coeval with shallow marine sedimentation in the east and southeast in the late thanetian–ypresian. although several geological studies have been carried out in the region, biostratigraphic studies are limited. yildiz et al. (2000) investigated the biostratigraphy and palaeoecology of the lower maastrichtian–paleocene sedimentary units, using trace fossils, planktonic foraminifera and calcareous nannofossils. they also determined the δ18o and δ13c isotope values from planktonic foraminifera tests and compared these with the abundance distributions of calcareous nannofossils purported to be sensitive to temperature, finding that the sea-surface water temperature and salinity were lower in the early maastrichtian than the palaeocene, increasing from the beginning of the danian. akoraler (2018) and gormus & akoraler (2019) investigated the benthic foraminiferal biostratigraphy and palaeoecology of the late cretaceous and maastrichtian sedimentary deposits of the kırıkkale and kalecik regions. they posited that article history: manuscript received december 10, 2021 revised manuscript accepted september 21, 2022 available online october 26, 2022 keywords: calcareous nannofossils, stressful environment, tectonic activity, latest maastrichtian, danian, neotethys g eo lo gi a c ro at ic a geologia croatica 75/3366 increased abundances of orbitoides indicated tolerable temperature conditions and a shallow basin in this interval. we investigated the nannofossil biostratigraphy in detail in the turbiditic sedimentary rocks in the kırıkkale basin in the i̇zmir–ankara zone––one of the important tectonic belts in turkey. in particular, we focused on determining changes in the maastrichtian to danian palaeoenvironment using the relative abundances of certain nannofossil species. 2. geological setting the study area was located in the i̇zmir–ankara zone. rocks belonging to the i̇zmir–ankara zone were tectonically emplaced above the rocks of the kırşehir block, while rocks belonging to the sakarya zone were tectonically placed above these (donmez et al., 2008). the rocks of the i̇zmir–ankara zone have tectonostratigraphic relationships with each other, the oldest unit comprising the late cretaceous artova ophiolite complex, and the youngest being paleocene–early eocene in age (figs. 1, 2). rocks from the i̇zmir–ankara zone typically comprise sediments from a closing basin (i.e. a basin with converging margins) that were deposited in the late cretaceous through to the early eocene. the relationships between sediments with turbiditic characteristics mainly occur in the form of underthrusts in a basin that was converging and closing (donmez et al., 2008). as explained above, the artova ophiolite complex tectonically overlies rocks of the kırşehir block, while rocks of the sakarya zone have been emplaced as thrust units above this (donmez et al., 2008). the kocatepe formation occurs above the artova ophiolite and comprises sequences of fragmented, clayey pelagic limestone and radiolarite-mudstone with calciturbidite intercalations (fig. 2). the unit has been interpreted as cenomanian–campanian in age based on benthic and planktonic fossils (akyurek et al., 1997). the cenomanian–campanian karadağ formation (akyurek et al., 1982, 1984) comprises volcaniclastic conglomerate, sandstone, mudstone and clayey limestone alternations, is turbiditic and has a tectonostratigraphic relationship with the artova ophiolite complex (donmez et al., 2008) (fig. 2). the lower figure 1. map of the study area showing the geology and sampled locations (simplified after donmez et al., 2008). g eologia c roatica ozer and kilic: the calcareous nannofossil record of the uppermost maastrichtian-lower palaeocene in the kırıkkale basin... 367 maastrichtian ilıcapınar formation (norman, 1972a) is overlain by the artova ophiolitic complex due to a thrust. the ilıcapınar formation is essentially turbiditic, comprising conglomerate and sandstone alternations. the samanlık formation can be correlated to the ilıcapınar formation (akyurek et al., 1984), has a ne–sw orientation and is mainly turbiditic, comprising yellow, green, brown and grey conglomerate, sandstone and shale sequences (figs. 1, 2). the unit comprises intermediate turbidites deposited in the lower part of a submarine fan at the same time as the ilıcapınar formation was being deposited (akyurek et al., 1984). the age of the samanlık formation is maastrichtian based on fossils (akyurek et al., 1984). the haymana formation (rigo de righi & cortesini, 1959) overlies the samanlık formation and comprises intermediate turbidites with conglomerate, sandstone and shale alternations deposited in the middle of the lower part of a submarine fan (akyurek et al., 1997) (fig. 2). the unit is considered to be of maastrichtian age, based on fossil evidence, and gradually grades into the overlying dizilitaşlar formation (donmez et al., 2008) (figs. 1, 2). the dizilitaşlar formation (norman, 1972a) comprises palaeocene–lower eocene turbiditic sediments deposited in a basin that developed in front of the artova ophiolite complex in the late cretaceous. the limestone blocks occurring in this formation are known as the kuşkayatepe limestone olistolith member (donmez et al., 2008) (figs. 1, 2). the dizilitaşlar formation transitions into the maastrichtian samanlık formation in some places, whereas it sits on top of the ophiolite, above an angular disconformity, in others (bi̇rgi̇li̇ et al., 1975). the çayraz formation unconformably overlies the dizilitaşlar formation (donmez et al., 2008) (fig. 1). above this is the sarıkaya formation, comprising conglomerates, sandstones and agglomerates containing volcanic material and, dominantly, andesitic lava. in this region, this formation is probably related to arc volcanism linked to a subduction event in the i̇zmir–ankara zone in the late cretaceous–palaeocene (donmez et al., 2008) (figs. 1, 2). 3. material and methods the samanlık and dizilitaşlar formations were the focus of this study, and their outcrops in the region were examined in three measured stratigraphic sections at different locations––the kırıkkale organised industrial zone, aşağı samanlık and the organised industrial region (fig. 1). the sample intervals varied based on the field conditions and the general structure of the geology, with samples being taken every 30 to 100 cm. a total of 99 samples were collected from the three measured sections––32 samples from the kırıkkale organised industrial zone (samples kos1–kos32), 40 samples from aşağı samanlık (samples as1– figure 2. generalised stratigraphic column of the kırıkkale area (after donmez et al., 2008). g eo lo gi a c ro at ic a geologia croatica 75/3368 ta bl e 1 th e ab un da nc es o f c al ca re ou s n an no fo ss ils w ith sp ec ie s d is tr ib ut io n in th e kı rık ka le o rg an iz ed in du st ria l z on e se ct io n (o sb ) n an no fo ss il sp ec ie s samples arkhangelskiella cymbiformis calculites obscurus ceratolithoides aculeus chiastozygus ampihons cribrosphaerella ehrenbergii eiffellithus eximius eiffellithus turriseiffelii lithraphidites carniolensis lithraphidites quadratus lithraphidites praequadratus microrhabdulus decoratus micrantholihus breviradiatus micula decussata micula murus prediscosphaera cretacea retecapsa crenulata watznaueria barnesiae braarudosphaera bigelowii markalius inversus thoracosphaera operculata zeugrhabdotus sigmoides coccolithus pelagicus cruciplacolithus intermedius cruciplacolithus primus cruciplacolithus tenuis futyania petalosa neochiastozygus distentus nannofossil biozones o sb 27 f r vr vr vr r n p2 o sb 26 f r vr vr r o sb 25 f f vr vr vr vr vr o sb 24 vr r vr r vr r vr o sb 23 vr vr vr vr o sb 22 vr vr vr vr vr vr r vr vr vr r o sb 21 vr vr r vr r vr vr vr vr vr o sb 20 r r vr vr n p1 o sb 19 ba rr en o f c al ca re ou s n an no fo ss ils o sb 18 o sb 17 o sb 16 f f o sb 15 f f o sb 14 vr r f f o sb 13 ba rr en o f c al ca re ou s n an no fo ss ils o sb 12 f vr f o sb 11 f f o sb 10 f f o sb 9 vr vr r f vr vr r r f u c2 0b tp o sb 8 vr vr vr vr vr vr vr vr r f vr vr vr o sb 7 vr vr vr vr vr vr vr f vr vr vr r o sb 6 vr vr vr vr r vr r f vr vr r r r vr u c2 0a tp o sb 5 vr vr vr vr vr vr r f vr r r vr o sb 4 vr vr vr vr vr vr vr r f vr vr r r r o sb 3 vr vr vr vr vr vr r r vr vr r r vr o sb 2 vr vr vr vr r r r vr r r vr o sb 1 vr vr vr vr vr r vr r r g eologia c roatica ozer and kilic: the calcareous nannofossil record of the uppermost maastrichtian-lower palaeocene in the kırıkkale basin... 369 as40) and 27 samples from the organised industrial region (samples osb1–osb27) the calcareous nannofossils were analysed in smear slides (bown & young, 1998). each slide was viewed at 1600x magnification with an oil-immersion lens under polarised light using a leica dm 2500p microscope. some of the nannofossils were photographed using a digital camera (leica dfc 295). the relative abundances of the nannofossils were estimated using the method described in wei (1988). based on this method, one or more specimens of one species in each field of view (fov) was classed as abundant (a), one in 2–10 fovs as common (c), one in 11–50 fovs as few (f), and one in 51–200 fovs as rare (r). 4. results the upper cretaceous (uc) standard nannofossil biozonation scheme developed by burnett et al. (1998) was used to determine the samples of late cretaceous age, whilst the np biozonation scheme of martini (1971) was used to date the early palaeocene samples. the species authors can be found in the book of calcareous nannofossil biostratigraphy and website (nannotax 3; https://www.mikrotax.org/nannotax3/index.php?dir=ntax_ cenozoic). 4.1. calcareous nannofossil implications of the deposits below, the distributions of the calcareous nannofossils and the biostratigraphy interpreted from them are discussed separately for each measured section. 4.1.1. kırıkkale organised industrial zone section lithology this section was measured along the road through the kırıkkale organised industrial zone (fig. 1). the samanlık formation crops out at the base of the section, passing upwards into the dizilitaşlar formation with a tectonic contact. the total thickness of the section was 37 m, with 27 samples being taken (fig. 3). twenty-one nannofossil genera and 27 nannofossil species were identified (table 1). the base of the section generally comprised brownish-grey, fineto medium-bedded sandstones and greyish-dark green laminated shale alternations of the samanlık formation (fig. 3). finebedded, cream-coloured clayey limestone layers were observed between these. while the section passed upwards into the dizilitaşlar formation, with a faulted contact, this contact befigure 3. lithostratigraphy, calcareous nannofossil abundances and biostratigraphy of the organised industrial zone section. g eo lo gi a c ro at ic a geologia croatica 75/3370 tween the two formations was covered in the study area. at the base of the dizilitaşlar formation, the sandstones beds are fine, but they thicken (10–30 cm) towards the upper part of the formation. fewer shales were observed in the upper part of the formation, where sandstone is more dominant. faulting and deformation structures were frequently encountered throughout the section. calcareous nannofossils the samples from the lowest 7 m of the section were determined to fall into the nannofossil biozone uc20atp, the assemblages containing mostly very rare lithraphidites quadratus bramlette & martini, 1964, the base of which defines the base of uc20 (fig. 3, table 1). zone uc20btp (defined from the base of micula murus (martini, 1961) bukry, 1973) was identified in the same lithology, from 7 to 13 m (fig. 3, table 1). the species richness and abundance of cretaceous nannofossil species in these samples was generally good, although the base of uc20b (sample osb7) exhibited low species abundance (fig. 3, table 1). low species abundances were noted in the alternating greenish-grey shale and dark brown sandstone beds of the dizilitaşlar formation (fig. 3, table 1). the samples from 13 to 28 m fall into nannofossil zone np1––the interval from the top occurrence of cretaceous nannofossils (and containing the bases of the earliest danian thoracosphaera operculata bramlette & martini, 1964 and braarudosphaera bigelowii (gran & braarud, 1935) deflandre, 1947 acmes) to the base of cruciplacolithus intermedius van heck & prins, 1987 (fig. 3, table 1). the samples from 28 to 37 m (alternating dark brown and grey, medium-bedded sandstones and dark green shales) were determined as belonging to np2, containing cruciplacolithus intermedius van heck & prins, 1987 (fig. 3, table 1). samples from the uppermost dizilitaşlar formation (above sample osb9) contained only scarce nannofossils (table 1). additionally, there were no nannofossils found in samples osb17– osb19 (table 1). although danian nannofossils were observed in sample osb20 and above, the species abundances were very figure 4. lithostratigraphy, calcareous nannofossil abundances and biostratigraphy of the aşağısamanlık section. g eologia c roatica ozer and kilic: the calcareous nannofossil record of the uppermost maastrichtian-lower palaeocene in the kırıkkale basin... 371 low (table 1). this data is compatible with nannofossil abundances decreasing in tandem with an increasing proportion of sand towards the top of the section. 4.1.2. section outside kırıkkale lithology this section was sampled at the entrance to the organized industrial zone immediately outside kırıkkale, on the road, almost 1 km south of hacıbalı village (fig. 1). the dizilitaşlar formation in this section is almost 135 m thick (fig. 4) and comprises yellow and brown, medium-bedded sandstones (fig. 5), greyishbrown, poorly-sorted conglomerate and greyish-brown, fine-bedded, occasionally laminated shale alternations. the same lithology continued from the base to the top, and a total of 32 samples were collected (fig. 4). the sandstones are generally medium to coarse grained, with normal grading. in some places in the middle part of the section, there are coarse-grained, unconsolidated sandstone layers reaching up to 1 m in thickness. the thickness of the turbiditic sandstones in the section reach almost 1 m. the shales beds are 30–40 cm thick. small-scale faulting and sliding are observed, causing disruption to the stratigraphy in a large part of the section. calcareous nannofossils generally, the samples contain low nannofossil species abundances, with 17 nannofossil genera and 19 species being identifigure 5. field photographs of normally graded sandstones in the section outside kırıkkale section. figure 6. lithostratigraphy, calcareous nannofossil abundances and biostratigraphy of the section outside kırıkkale. g eo lo gi a c ro at ic a geologia croatica 75/3372 ta bl e 2 th e ab un da nc es o f c al ca re ou s n an no fo ss ils w ith sp ec ie s d is tr ib ut io n in th e o ut si de k ırı kk al e (k o s) se ct io n n an no fo ss il sp ec ie s samples arkhangelskiella cymbiformis chiastozygus ampihons cribrosphaerella ehrenbergii micrantholihus breviradiatus micula decussata microrhabdulus decoratus prediscosphaera cretacea zeugrhabdotus embergeri watznaueria barnesiae braarudosphaera bigelowii markalius inversus thoracosphaera operculata zeugrhabdotus sigmoides coccolithus pelagicus cruciplacolithus primus cruciplacolithus intermedius futyania petalosa neochiastozygus distentus neocrepidolithus fossus nannofossil biozones ko s3 2 f vr ko s3 1 f vr vr ko s3 0 vr f f vr vr vr r vr ko s2 9 f f vr vr vr r ko s2 8 vr f f vr vr vr vr vr ko s2 7 vr f f vr vr vr r ko s2 6 f vr vr ko s2 5 f vr ko s2 4 f vr vr ko s2 3 f vr ko s2 2 f vr vr ko s2 1 r f vr vr r vr vr ko s2 0 ba rr en o f c al ca re ou s n an no fo ss ils n p2 ko s1 9 ko s1 8 r r vr ko s1 7 ba rr en o f c al ca re ou s n an no fo ss ils ko s1 6 vr r r vr r r vr vr ko s1 5 ba rr en o f c al ca re ou s n an no fo ss ils ko s1 4 f vr r ko s1 3 f vr r ko s1 2 f vr r ko s1 1 f vr r ko s1 0 f vr r vr vr ko s9 vr r f r r vr ko s8 r vr vr r ko s7 vr r f f vr vr vr r r ko s6 vr r f f vr vr vr vr r ko s5 r f f vr vr vr r ko s4 vr r r f vr vr vr r vr vr ko s3 vr vr r r vr r r f r n p1 ko s2 vr vr r r vr r r f r r ko s1 vr r r vr r f r r g eologia c roatica ozer and kilic: the calcareous nannofossil record of the uppermost maastrichtian-lower palaeocene in the kırıkkale basin... 373 fied (table 2). two biozones were identified (fig. 4). the lowest 6 m of the section contained both cretaceous and danian nannofossils (fig. 4). the alternating brown sandstone and greyish-dark green shales were determined as representing zone np1, from the last cretaceous nannofossils to the base of cruciplacolithus primus perch-nielsen, 1977 (fig. 4, table 2). the relative abundance of cretaceous nannofossil species decreased up-section. above sample kos9, the taxa present were mostly danian (table 2), although their species abundances were generally very low. the first occurrence of cruciplacolithus intermedius van heck & prins, 1987 was found in the same lithology, at 5 m, and was used to indicate the base of the np2 zone (fig. 4, table 2). this marker species has been found to be more appropriate for dating marginal sea sediments (thibault et al., 2018) where the definitive marker, cruciplacolithus tenuis (stradner, 1961) hay & mohler 1967, is absent, as was the case here, possibly due to the unstable environmental conditions in the region. some samples were barren, while other samples only contained very low numbers of species. although few in number, thoracosphaera operculata bramlette & martini, 1964 and braarudosphaera bigelowii (gran & braarud, 1935) deflandre, 1947 dominated in this section (table 2) as in the previous section (table 1). 4.1.3. aşağı samanlık section lithology the aşağı samanlık section was sampled on the road to aşağı samanlık village (at the junction with the kırıkkale–çankırı road) (fig. 1). the section is 50 m thick and comprises dark green and grey shales and dark brown sandstone alternations belonging to the dizilitaşlar formation throughout (fig. 6). forty samples were taken, which yielded 22 nannofossil genera and 25 nannofossil species (table 3). the aşağı samanlık section exhibits typical turbiditic features, with laminated shales and fineto medium-bedded sandstones (fig. 7). small faults and slides were observed in the section. the shale beds at the base of the section are generally 70–80 cm thick, while the sandstone beds vary from 2 to 5 cm thick. towards the top of the section, the sandstone beds occasionally reach 10 cm thick. the number of occasional sandstone beds increases towards the top of the section, where they reach 10–15 cm thick, while the shale beds are relatively decreased in number. rarely, trace fossils were observed in the sandstone layers. within the sequence, there are unconsolidated, loose-textured conglomerate levels, 70–80 cm thick. calcareous nannofossils the samples from the lower part of the section contained danian and cretaceous nannofossils. there were relatively higher species abundances in the shale samples (table 3). cruciplacolithus intermedius van heck & prins, 1987 has been found in the region in the upper part of np1, close to the base of np2, according to thibault et al. (2018) (figs. 6, 8, table 3). zone np2 was interpreted up to a height of 50 m in the section (fig. 6, table 3). thibault et al. (2018) identified the bases of np1 and np2 using a cruciplacolithus lineage involving different sizes of cruciplacolithus primus perch-nielsen, 1977. however, in our samples, small and large (>7 µm) cruciplacolithus primus perchnielsen, 1977 specimens could not be discriminated between. scattered occurrences of cruciplacolithus primus perch-nielsen, 1977 and cruciplacolithus intermedius van heck & prins, 1987 were found in the lower part of the section, encountered together with cruciplacolithus primus perch-nielsen, 1977, which was not found above sample as10, whereas cruciplacolithus intermedius van heck & prins, 1987 was present in a few samples above this figure 7. field view of the dizilitaşlar formation taken from the aşağısamanlık section showing shale–sandstone alternations. figure 8. summary of the calcareous nannofossil biozonation schemes applied to the maastrichtian–danian sediments, along with age estimates for the study area, correlated with those of other studies from different middleand low-latitude localities. g eo lo gi a c ro at ic a geologia croatica 75/3374 ta bl e 3 th e ab un da nc es o f c al ca re ou s n an no fo ss ils w ith sp ec ie s d is tr ib ut io n in th e a şa ğı s am an lık (a s) st ra tig ra ph ic se ct io n n an no fo ss il sp ec ie s samples arkhangelskiella cymbiformis cribrosphaerella ehrenbergii eiffellithus turriseiffelii lithraphidites quadratus lucianorhabdus cayeuxii microrhabdulus decoratus micrantholihus breviradiatus micula decussata prediscosphaera cretacea retecapsa crenulata uniplanarius gothicus watznaueria barnesiae braarudosphaera bigelowii markalius inversus thoracosphaera operculata zeugrhabdotus sigmoides biantholithus sparsus futyania petalosa coccolithus pelagicus cruciplacolithus intermedius cruciplacolithus primus neochiastozygus imbriei neochiastozygus modestus neocrepidolithus neocrassus neocrepidolithus fossus nannofossil biozone a s4 0 f a s3 9 f a s3 8 f f a s3 7 r f f r r a s3 6 f f r a s3 5 r f f r a s3 4 f f r r a s3 3 f f r a s3 2 f f r a s3 1 vr r vr f f r r vr a s3 0 r vr f f r a s2 9 r vr f f r a s2 8 r r vr f f r a s2 7 vr vr r vr r r vr r f vr r vr a s2 6 vr vr vr r vr f r f r a s2 5 vr r r r vr f f vr a s2 4 vr vr vr vr vr f r f r a s2 3 vr vr r vr vr f f r vr vr a s2 2 vr vr r vr vr f r f r vr vr a s2 1 vr vr r vr vr f r f r vr vr n p2 a s2 0 vr vr r r vr vr f r f r vr a s1 9 vr vr r r vr vr f r f r vr a s1 8 vr vr r r vr vr f r f r vr a s1 7 vr vr vr r f f r a s1 6 vr vr r r f f r a s1 5 vr vr vr r r f f r a s1 4 vr vr r f f r a s1 3 vr vr r r r r f f vr r vr vr a s1 2 vr vr r r f f r a s1 1 vr vr r f f r vr a s1 0 vr vr vr f r f vr vr r r vr a s9 vr vr vr r vr r f r r vr vr vr vr a s8 vr vr vr r vr r f r r vr vr vr vr vr a s7 vr vr vr vr r f r r vr vr a s6 vr vr vr r vr r f r r vr vr vr a s5 vr vr vr r vr r f r r vr vr vr a s4 vr vr vr r r r vr r f r r a s3 vr vr r r vr r r vr r f r r a s2 r f r r r vr vr a s1 r vr vr r f r r vr vr g eologia c roatica ozer and kilic: the calcareous nannofossil record of the uppermost maastrichtian-lower palaeocene in the kırıkkale basin... 375 level. the cruciplacolithus lineage was not observed in np2 here possibly because of the unstable regional conditions. nannofossil species abundances decreased towards the top of the section, particularly from sample as30, with only a few reworked cretaceous specimens among a small but greater proportion of danian species being identified in the uppermost beds (table 3). samples with a high proportions of sand appeared to have reduced species richness. 5. discussion 5.1. biostratigraphy the samanlık and dizilitaşlar formations contain turbidites with high sand contents. upper maastrichtian nannofossil species were only identified in the kırıkkale organized industrial zone section (fig. 3). in this section, upper maastrichtian species abundances were generally very low, apart from micula decussate vekshina, 1959, microrhabdulus decorates deflandre, 1959 and watznaueria barnesiae (black, 1959) perch-nielsen, 1968 (table 1), with the species richness and relative abundances of the nannofossils showing a significant decrease at the k–pg boundary (table 1). in the study area, the k–pg boundary was not continuous, but was identified based on the increased abundances (albeit still only a few specimens) of thoracosphaera operculata bramlette & martini, 1964 and braarudosphaera bigelowii (gran & braarud, 1935) deflandre, 1947 (fig. 3, table 1) in the danian in the organised industrial zone section. nannofossils were still rare and generally poorly preserved in the danian samples, while samples that contained high proportions of sand tended to be barren of nannofossils (tables 1, 3). the base of np2 is defined by the base of cruciplacolithus tenuis (stradner, 1961) hay & mohler 1967, which has been dated at 65.538 ma in the north pacific (westerhold et al., 2008) and at 65.094 ma in the south atlantic (thibault et al., 2018). however, according to the shipboard scientific party (2004), the base of cruciplacolithus tenuis (stradner, 1961) hay & mohler 1967 is at 65.5828 ma in the south atlantic, which agrees with the age in the pacific ocean and the base of np2. the base of np2 in the studied region can be approximated by large (>7 µm) specimens of cruciplacolithus primus perch-nielsen, 1977, which have been included in cruciplacolithus intermedius van heck & prins, 1987 (= cruciplacolithus tenuis s.l. of perchnielsen, 1985) by thibault et al. (2018). thibault et al. (2018) used the base of cruciplacolithus cf. c. intermedius, dated at 65.709 ma in the south atlantic, to approximate the base of np2, while the base of c. intermedius s.s. has been astronomically calibrated to 65.274 ma (westerhold et al., 2008). westerhold et al. (2008) also explained that the base of np2, as determined by the base of cruciplacolithus intermedius van heck & prins, 1987, correlates with, or lies above, the top of the first recovery phase of the δ14c isotope curve for the region. gilleaudeau et al. (2018) also identified the base of np2 using the base of cruciplacolithus intermedius van heck & prins, 1987. the kırıkkale basin was a deep-sea basin that prevailed during unstable environmental conditions due to tectonic activity in the maastrichtian through the early danian. in the study area, cruciplacolithus tenuis (stradner, 1961) hay & mohler 1967, the actual marker for the base of np2, was not found in this unstable environment except for in one section, and so the base of np2 had to be correlated using the base of cruciplacolithus intermedius van heck & prins, 1987 (fig. 8). in fig. 8, the nannofossil zones identified in this study are compared with the stratigraphic distributions of selected nannofossils from other tethyan localities with similar assemblages and similar ages, including the kırıkkale basin. 5.2. palaeoecological interpretation the asteroid impact at the k–pg boundary caused dramatic biotic and biogeochemical changes in the oceans, and planktonic foraminifera and calcareous nannofossils were severely affected by the ensuing environmental crisis in the marine pelagic ecosystem (smit, 1982; pospichal & wise, 1990; berggren & norris, 1997; molina et al., 1998; huber et al., 2002; bown, 2005; fuqua et al., 2008; schulte et al., 2010; guerra et al., 2021). some nannofossil species survived the impact event, adapting to the changed environmental conditions (bown, 2005). here, the k–pg boundary was determined based on a significant decrease in the abundance of nannofossil species, an increase in survivor cretaceous species, such as thoracosphaera operculata bramlette & martini, 1964, and observations of the new palaeocene taxa (lamolda et al., 2005; bernaola & monechi, 2007). few to rare abundances of micula decussate vekshina, 1959 and watznaueria barnesiae (black, 1959) perch-nielsen, 1968 occurred in the upper maastrichtian samples in the study area (table 1). micula decussate vekshina, 1959 has been interpreted, in some studies, as a species that thrives in low-productivity, relatively cool and stressed environments (watkins & selftrail, 2005; keller et al., 2007; thibault & gardin, 2007; mahanipour et al., 2022). watznaueria barnesiae (black, 1959) perch-nielsen, 1968 is considered to be a warm water, cosmopolitan, eutrophic and opportunistic species in lowlatitude regions by mutterlose (1996), pospichal (1996) and lees (2002), and as being more efficiently able to adapt to different environmental and stress conditions by, for example, aguado et al. (2016). lees et al. (2005) explained that watznaueria barnesiae (black, 1959) perch-nielsen, 1968 is likely to have been ecologically r-selected for rapid reproduction in heightened nutrient. both watznaueria barnesiae (black, 1959) perch-nielsen, 1968 and micula decussate vekshina, 1959 are considered to be highly resistant to dissolution and have been used to test the preservation of nannofossil assemblages (hill, 1975; thierstein, 1980). in the kırıkkale basin, however, rare occurrences of micula decussate vekshina, 1959 and watznaueria barnesiae (black, 1959) perch-nielsen, 1968, in tandem with low abundances of other taxa, are interpreted as being possibly due to the unstable and stressful environment of the late maastrichtian, which is in agreement with previous foraminifera data determining a shallower basin and less saline environment with decreased temperature. braarudosphaera bigelowii (gran & braarud, 1935) deflandre, 1947 and thoracosphaera operculata bramlette & martini, 1964 were found to be rare in the maastrichtian, increasing to the ‘few’ abundance category, except in some samples, in the danian (tables 1, 3). braarudosphaera spp. became important components of the nannofossil assemblages in the danian after the k–pg extinction event. braarudosphaera bigelowii (gran & braarud, 1935) deflandre, 1947 evolved in the cretaceous and is common and/or persistent in the cretaceous of some tethyan regions (bernaola & monechi, 2007). jones et al. (2019) stated that this species survived after the k–pg event because it was able to adapt to the ensuing unstable environment, as also explained by pospichal & bralower (1992), peaking in g eo lo gi a c ro at ic a geologia croatica 75/3376 abundance just above the k–pg boundary. braarudosphaera bigelowii (gran & braarud, 1935) deflandre, 1947 is also very resistant to diagenetic alteration (jones et al., 2019). high abundances of braarudosphaera bigelowii (gran & braarud, 1935) deflandre, 1947 have mostly been associated with low-salinity coastal waters (peleo-alampay et al., 1999; bartol et al., 2008), the influx of terrestrial material into oceanic waters (švábenická, 1999) and eutrophication (cunha & shimabukuro, 1997). it is believed to have evolved in unusual palaeoceanographic conditions and has been viewed as an opportunist that responds to reduced competition (thierstein et al., 2004). several researchers have reported episodes of braarudosphaera bigelowii (gran & braarud, 1935) deflandre, 1947 enrichment in open-ocean sediments (siesser et al., 1992; figure 9. selected calcareous nannofossil images identified in the sections. all photomicrographs were taken using polarised light. a–braarudosphaera bigelowii (gran & braarud, 1935) deflandre, 1947, sample as1; b–micrantholithus breviradiatus bown 2005, sample as21; c–thoracosphaera operculata bramlette & martini, 1964, sample as1; d–cruciplacolithus tenuis (stradner, 1961) hay & mohler 1967, sample osb21; e–markalius inversus (deflandre, 1954) bramlette & martini 1964, sample as22; f–coccolithus pelagicus (wallich 1877) schiller 1930, sample as37; g–zeugrhabdotus embergeri (noël 1959) perch-nielsen 1984, sample kos9; h– neocrepidolithus fossus romein, 1977) romein 1979, sample as2; i–cruciplacolithus intermedius van heck & prins, 1987, sample as1; j–futyania petalosa (ellis & lohmann, 1973) varol 1989, sample osb27; k–cruciplacolithus intermedius van heck & prins, 1987, sample kos5; l–zeugrhabdotus sigmoides (bramlette & sullivan, 1961) bown & young 1997, sample as10; m–neocrepidolithus neocrassus (perch-nielsen, 1968) romein 1979, sample as8; n–neochiastozygus modestus perch-nielsen 1971, sample as13; o–neochiastozygus distentus (bramlette & sullivan, 1961) perch-nielsen 1971, sample osb21; p–cruciplacolithus intermedius van heck & prins, 1987, sample as8; q–cruciplacolithus primus perch-nielsen, 1977 (large), sample osb21; r–cruciplacolithus primus perch-nielsen, 1977 (small), sample osb22. g eologia c roatica ozer and kilic: the calcareous nannofossil record of the uppermost maastrichtian-lower palaeocene in the kırıkkale basin... 377 peleo-alampay et al., 1999; kelly et al., 2003; eisenach & kelly, 2004; gamboa & shimabukuro, 2006). the cause of unstable environmental conditions coincides with the tectonic and volcanic activity in the region that induced dramatic change in nannoplankton assemblage linked to the subduction event in the i̇zmir–ankara zone. thoracosphaera operculata bramlette & martini, 1964 is another species that evolved in the cretaceous and survived into the danian, being observed at the k–pg boundary in most studies on midand low-latitude regions (tantawy, 2003; molina et al., 2006; kaya-ozer, 2014; kaya-ozer & temiz, 2019; mahanipour et al., 2021). the increasing abundance figure 10. selected calcareous nannofossil images identified in the sections. all photomicrographs were taken using polarised light. a–arkhangelskiella cymbiformis vekshina 1959, sample osb5; b–prediscosphaera cretacea (arkhangelsky, 1912) gartner 1968, sample as1; c–retecapsa crenulata (bramlette & martini, 1964) grün & allemann 1975, sample as1; d–chiastozygus amphipons (bramlette & martini, 1964) gartner 1968, sample osb2; e–micula decussate vekshina, 1959, sample osb4; f–micula decussate vekshina, 1959, sample osb8; g–eiffellithus turriseiffelii (deflandre, 1954) reinhardt 1965, sample osb4; h–micula murus (martini, 1961) bukry, 1973, sample osb8; i–watznaueria barnesiae (black, 1959) perch-nielsen, 1968, sample as26; j–watznaueria barnesiae (black, 1959) perch-nielsen, 1968, sample osb1; k–calculites obscurus (deflandre, 1959) prins & sissingh in sissingh 1977, sample osb7; l–microrhabdulus decorates deflandre, 1959, sample osb2; m–cribrosphaerella ehrenbergii (arkhangelsky, 1912) deflandre in piveteau 1952, sample as17; n–cribrosphaerella ehrenbergii (arkhangelsky, 1912) deflandre in piveteau 1952, sample as17; o–ceratolithoides aculeus stradner, 1961) prins & sissingh in sissingh 1977, sample osb7; p–lithraphidites quadratus bramlette & martini, 1964, sample obs8; q–lithraphidites carniolensis deflandre 1963, sample osb4; r–micula decussate vekshina, 1959, sample osb1; s–uniplanarius gothicus (deflandre, 1959) hattner & wise 1983, sample as5; t–micula murus (martini, 1961) bukry, 1973, sample osb7; u–lithraphidites praequadratus roth 1978, sample osb8; v–lucianorhabdus cayeuxii deflandre 1959, sample as15. g eo lo gi a c ro at ic a geologia croatica 75/3378 of this species across the k–pg suggests it is an opportunistic species, and it has been interpreted as indicating a high-stress environment (tantawy, 2003; aguado et al., 2005; kayaozer, 2014). acmes of thoracosphaera operculata bramlette & martini, 1964 may correlate with episodes of increased environmental stress, higher atmospheric co2 contents, fluctuations in marine salinity and ph, and/or significant warming over a short period of time, such as the conditions that followed the k– pg boundary event (lamolda et al., 2005). in the danian, the few relative abundances of thoracosphaera operculata bramlette & martini, 1964 and braarudosphaera bigelowii (gran & braarud, 1935) deflandre, 1947 in assemblages also containing rare futyania are interpreted as indicating stressful conditions and significant environmental perturbations in the kırıkkale basin that resulted from the tectonic activity that occurred in the danian in the study area. the lack of species in some samples, especially those from sandstonedominated intervals, was notable. some of the species found in this study are illustrated in figs. 9 and 10. 6. conclusions a detailed nannofossil biostratigraphic analysis was performed on the samanlık and dizilitaşlar formations, deposited in the kırıkkale basin. four nannofossil biozones–uc20atp and uc20btp and np1 and np2–were identified, indicating the late maastrichtian to danian periods, in three stratigraphic sections. the nannofossil species abundances were generally low in both the upper maastrichtian and the danian. the low abundances of micula decussate vekshina, 1959 and the lack of species richness in the upper maastrichtian suggest stressful environmental conditions with lower temperature and salinity. the k–pg boundary was not continuous but was identified by the relatively increased abundances of braarudosphaera bigelowii (gran & braarud, 1935) deflandre, 1947 and thoracosphaera operculata bramlette & martini, 1964. in the danian, the low species richness and the presence of opportunistic species, such as braarudosphaera bigelowii (gran & braarud, 1935) deflandre, 1947 and thoracosphaera operculata bramlette & martini, 1964, were interpreted as indicating stressed environmental conditions in the study area. the finding of reworked fossils and the low species abundances accord with the tectonically active environment of the maastrichtian through the palaeocene here. acknowledgement the authors wish to thank the bozok university scientific research projects unit (project no. 6602a-mmf/17-70) for supporting this study. we would also like to thank ines galovic and nicolas thibault for their valuable corrections and comments and jackie lees for english editing, which contributed to the development of the manuscript. references aguado, r., lamolda, m.a. & maurrasse, f.j.m.r. (2005): nanofossiles del limite cretacico/terciario en beloc (haiti): bioestratigrafia, composicion de las asociaciones e implicaciones paleoclimaticas.– journal of iberian geology, 31, 9–24. aguado, r., reolid, m. & molina, e. (2016): response of calcareous nannoplankton to the late cretaceous oceanic anoxic event 2 at oued bahloul (central tunisia).–palaeogeography, palaeoclimatology, palaeoecology, 459, 289–305. doi: 10.1016/j.palaeo.2016.07.016 akoraler, h. (2018): malıboğazı-tilkikoy (kalecik, ankara) ve irmak (kırıkkale) çevrelerindeki ust kretase çökellerinin bentik foraminiferleri (in turkish).– master’s thesis, ankara university, 155 p. akyurek, b., bilginer, e., akbaş, b., hepsen, n., pehlivan, s., sunu, o., soysal, y., deger, z., catal, e., sozeri, b. & yildirim, h. (1982): ankara-elmadağ-kalecik dolayının jeolojisi (in turkish).– mta report no. 7298 (unpublished), ankara. akyurek, b., bi̇lgi̇ner, e., akbaş, b., hepşen, n., pehli̇van, ş., sunu, o., soysal, y., değer, z., çatal, e., sozeri̇, b., yildirim, h. & hakyemez, y. (1984): ankara-elmadağ-kalecik dolayının temel jeoloji ozellikleri (in turkish).– jeoloji mühendisliği dergisi, 20, 31–46. akyurek, b., duru, m., sutçu, y. f., papak, i̇., şaroğlu, f., pehli̇van, n., gonenç, o., grani̇t, s. & yaşar, t. (1997): 1/100,000 olçekli açınsama nitelikli türkiye jeoloji haritaları serisi, ankara f-15 paftası (in turkish).– mta publications, ankara. arkhangelsky, a.d. (1912): upper cretaceous deposits of east european russia.– materialien zur geologie russlands, 25, 1–631. aubry, m.p. & salem, r. (2013): the dababiya quarry core: coccolith biostratigraphy.– stratigraphy, 9, 241–259. bartol, m., pavsic, j., dobnikar, m. & bernasconi, s. m. (2008): unusual braarudosphaera bigelowii and micrantholithus vesper enrichment in the early miocene sediments from the slovenian corridor, a seaway linking the central paratethys and the mediterranean.– palaeogeography palaeoclimatology palaeoecology, 267, 77–88. doi: 10.1016/j.palaeo.2008.06.005 berggren, w.a. & norris, r.d. (1997): biostratigraphy, phylogeny and systematics of paleocene tropical planktic foraminifera.– micropaleontology, 43, 1–116. bernaola, g. & monechi, s. (2007): calcareous nannofossil extinction and survivorship across the cretaceous−paleogene boundary at walvis ridge (odp hole 1262c, south atlantic ocean).– palaeogeography, palaeoclimatology, palaeoecology, 255, 132–156. doi: 10.1016/j.palaeo.2007.02.045 bi̇rgi̇li̇, ş., yoldaş, r. & unalan, g. (1975): çankırı-çorum havzasının jeolojisi ve petrol olanakları (in turkish).– mta report no. 5621 (unpublished), ankara. bown, p.r. (2005): selective calcareous nannoplankton survivorship at the cretaceous– tertiary boundary.– geology, 33, 653–656. doi: 10.1130/g21566ar.1 bown, p.r. & young, j.r. (1997): mesozoic calcareous nannoplankton classification.–journal of nannoplankton research, 19, 1, 21–36. bown, p.r. & young, j.r. (1998): techniques.– in: bown, p.r. (ed.): calcareous nannofossil biostratigraphy. kluwer academic publisher, the netherlands, 16–28. doi: 10.1007/978-94-011-4902-0_2 bramlette, m.n. & martini, e. (1964): the great change in calcareous nannoplankton fossils between the maestrichtian and danian.– micropaleontology, 10, 3, 291–322. doi: 10.2307/1484577 bukry, d. (1973): phytoplankton stratigraphy, deep sea drilling project leg 20, western pacific ocean.– initial reports of the deep sea drilling project, 20, 307–317. burnett, j.a. (1998): upper cretaceous. -in: bown, p.r. (ed.): calcareous nannofossil biostratigraphy. kluwer academic publisher, london, 132–165. doi: 10.1007/978-94-011-4902-0_6 coccioni, r., frontalini, f., bancalà, g., fornaciari, e., jovane, l. & sprovieri, m. (2010): the dan-c2 hyperthermal event at gubbio (italy): global implications, environmental effects, and cause(s).– earth and planetary science letters, 297, 1–2, 298–305. doi: 10.1016/j.epsl.2010.06.031 deflandre, g. (1947): braarudoshphaera nov. gen., type d’une famille nouvelle de coccolithophoridés actuels à éléments composites.– comptes rendus de l’académie des sciences, 225, 439–441. deflandre, g. (1959): sur des nannofossiles calcaires et leur systématique.– revue de micropaléontologie, 2, 127–152. deflandre, g. (1963): sur des microrhabdulidés, famille nouvelle de nannofossiles calcaires.– comptes rendus hebdomadaires des séances de l’académie des sciences, paris, 256, 16, 3484–3486. donmez, m., akçay, a.b., kara, h., yergok, a.f. & esenturk, k. (2008): 1/100,000 olçekli açınsama nitelikli türkiye jeolojisi haritaları serisi, kırşehir i̇-30 paftası (in turkish).– mta publications, ankara. erkan, y. (1975): orta anadolu masifi güneybatısında (kırşehir bölgesinde) etkili rejyonal metamorfizmanın petrolojik incelenmesi (in turkish).– unpubl. phd thesis, hacettepe university. 147 pp. fuqua, l.m., bralower, t.j., arthur, m.a. & patzkowsky, m.e. (2008): evolution of calcareous nannoplankton and the recovery of marine food webs after the cretaceous–paleocene mass extinction.– palaios, 23, 4, 185–194. doi: 10.2110/ palo.2007.p07-004r gartner, s. (1968): coccoliths and related calcareous nannofossils from upper cretaceous deposits of texas and arkansas. – university of kansas paleontological contributions, 48, 1, 1–56. gilleaudeau, g.j., voegelin, a.r., thibault, n., moreau, j., ullmann, c.v., klaebe, r.m., korte, c. & frei, r. (2018): stable isotope records across the cretaceous–paleogene transition, stevns klint, denmark: new insights from the chromium isotope system.– geochimica et cosmochimica acta, 235, 305–332. doi: 10.1016/j.gca.2018.04.028 g eologia c roatica ozer and kilic: the calcareous nannofossil record of the uppermost maastrichtian-lower palaeocene in the kırıkkale basin... 379 gokçen, n. (1977): irmak-hacıbalı-mahmutlar-ankara, yahşıyan üst kretase-paleojen istifinin biyostratigrafik incelemesi (in turkish).– yerbilimleri, 2, 2, 129–144. goncuoğlu, m.c. (1981): niğde masifinde viridinli gnaysın kökeni (in turkish).– türkiye jeoloji kurumu bülteni, 24, 45–50. gormuş, m. & akoraler, h. (2019): benthic foraminifera of the maastrichtian sediments from the malıboğazı (kalecik, ankara) and irmak (kırıkkale) areas in türkiye. world multidisciplinary earth sciences symposium (wmess 2019), iop conference series: earth and environmental science, prague, 362, 1–10. gorur, n., tuysuz, o. & şengor, a.m.c. (1998): tectonic evolution of the central anatolian basins.– international geology review, 40, 831–850. gran, h. h. & braarud, t. (1935): a quantitative study of the phytoplankton in the bay of fundy and the gulf of maine (including observations on hydrography, chemistry, and turbidity).– journal of the biological board of canada, 1, 279–467. grün, w. & allemann, f. (1975): the lower cretaceous of caravaca (spain): berriasian calcareous nannoplankton of the miravetes section (subbetic zone, prov. of murcia).– eclogae geologica helvetica, 68, 1, 147–211. guerra, r.m., concheyro, a., kochhan, k.g.d., bom, m.h.h., ceolin, d., musso, t., savian, j.f. & fauth, g. (2021): calcareous microfossils and paleoenvironmental changes across the cretaceous–paleogene (k–pg) boundary at the cerro azul section, neuquén basin, argentina.– palaeogeography, palaeoclimatology, palaeoecology, 567, 1, 110217. doi: 10.1016/j.palaeo.2021.110217 hattner, j.g. & wise, s.w. (1980): upper cretaceous calcareous nannofossil biostratigraphy of south carolina.– south carolina geology, 24, 41–117. hay, w. w. & mohler, h. p. (1967): calcareous nannoplankton from early tertiary rocks at pont labau, france, and paleocene–eocene correlations.– journal of paleontology, 41, 1505–1541. hill, m.e. (1975): selective dissolution of mid-cretaceous (cenomanian) calcareous nannofossils.– micropaleontology, 21, 2, 227–235. doi: 10.2307/1485025 huber, b.t., macleod, k.g. & norris, r.d. (2002): abrupt extinction and subsequent reworking of cretaceous planktonic foraminifera across the cretaceous– tertiary boundary: evidence from the subtropical north atlantic.– geological society of america, special paper, 356, 277–289. doi: 10.1130/0-8137-2356-6.277 jones, h.l., lowery, c.m. & bralower t.j. (2019): delayed calcareous nannoplankton boom–bust successions in the earliest paleocene chicxulub (mexico) impact crater.– geology, 47, 753–756. doi: 10.1130/g46143.1 kasem, a.m., wise, s., faris, m., farouk, s. & zahran, e. (2017): calcareous nannofossil biostratigraphy of the uppermost maastrichtian–lower paleocene at the misheiti section, east central sinai, egypt.– revue de micropaléontologie, 60, 179–192. doi: 10.1016/j.revmic.2017.05.002 kaya ozer, c. (2014): calcareous nannofossil assemblage changes and stable isotope data from maastrichtian to selandian in the akveren formation, western black sea. turkey.– arabian journal of geosciences, 7, 1233–1247. doi: 10.1007/s12517-0130856-y kaya ozer, c. & temi̇z, u. (2019): calcareous nannofossil and planktonic foraminiferal biostratigraphy of santonian to danian in göynük basin, bolu, turkey.– journal of african earth sciences, 149, 235–270. doi: 10.1016/j.jafrearsci.2018.08.011 keller, g., adatte, t., berner, z., harting, m., baum, g., prauss, m., tantawy, a. & stueben, d. (2007): chicxulub impact predates k–t boundary: new evidence from brazos, texas.– earth and planetary science letters, 255, 3–4, 339–356. doi: 10.1016/j.epsl.2006.12.026 ketin, i. (1961): über die magmatischen erscheinungen in der turkei.– bulletin of the geological society of turkey, 7, 2, 1–16. lees, j.a. (2002): calcareous nannofossil biogeography illustrates palaeoclimate change in the late cretaceous indian ocean.– cretaceous research, 23, 537–634. doi: 10.1006/cres.2003.1021 lees, j.a., bown, p.r. & mattioli, e. (2005): problem with proxies? cautionary tales of calcareous nannofossil paleoenvironmental indicators.– micropaleontology, 51, 4, 333–343. doi: 10.2113/gsmicropal.51.4.333 mahanipour, a., mutterlose, j. & parandavar, m. (2022): integrated bio and chemostratigraphy of the cretaceous – paleogene boundary interval in the zagros basin (iran, central tethys).– palaeogeography, palaeoclimatology, palaeoecology, 587, 1–12. doi: 10.1016/j.palaeo.2021.110785 mahanipour, a., parandavar, m. & youssef, m. (2021): calcareous nannofossil biostratigraphy of the late cretaceous‒early paleocene interval in the zagros basin (southeastern tethys), iran. – alcheringa, 45, 1, 95–108. doi: 10.1080/03115518.2021.1872702 martini, e. (1971): standard tertiary and quaternary calcareous nannoplankton zonation.–in: proceedings of the 2nd planktonic conference, roma, 739–785. molina, e., alegret, l., arenillas, i., arz, j.a., gallala, n., hardenbol, j., von salis, k., steurbaut, e., vandenberghe, n. & zaghbib-turki, d. (2006): the global boundary stratotype section and point for the base of the danian stage (paleocene, paleogene, “tertiary”, cenozoic) at el kef tunisia–original definition and revision.– episodes, 29, 263–373. doi: 10.18814/ epiiugs/2006/v29i4/004 molina, e., arenillas, j. & arz, j.a. (1998): mass extinction in planktic foraminifera at the cretaceous/tertiary boundary in subtropical and temperate latitudes.– bulletin de la société géologique de france, 169, 351–363. mutterlose, j. (1996): calcareous nannofossil palaeoceanography of the early cretaceous of the nw europe.– mitteilungen aus dem geologischen staatsinstitut in hamburg, 77, 291–313. norman, t. (1972a): ankara yahşihan bölgesinde üst kretase–alt tersiyer i̇stifinin stratigrafisi (in turkish). -mta bilimsel ve teknik araştırma kurulu projesi, 180– 276. norman, t. (1972b): ankara yahşihan bölgesinde ust kretase–tersiyer yerkabuğu hareketleri (in turkish).– kuzey anadolu fay sempozyumu tebliğleri, ankara, 97–108. perch-nielsen, k. (1968): der feinbau und die klassifikation der coccolithen aus dem maastrichtien von danemark.– det kongelige danske videnskabernes selskabs biologiske skrifter, 16, 1, 1–96. perch-nielsen, k. (1971): neue coccolithen aus dem paläozän von dänemark, der bucht von biskaya und dem eozän der labrador see.– bulletin of the geological society of denmark, 21, 51–66. perch-nielsen, k. (1977): albian to pleistocene calcareous nannofossils from the western south atlantic.– initial reports of the deep sea drilling project, 39, 699– 823. perch-nielsen, k. (1984): validation of new combinations.– ina newsletter, 6, 1, 42–46. perch-nielsen, k. (1985): cenozoic calcareous nannofossils.– in: bolli, h.m., saunders, j.b. & perch-nielsen, k. (eds): plankton stratigraphy. cambridge university press. cambridge, 422–454. perez-rodríguez, i., lees, j.a., larrasoaña, j.c., arz, j.a. & arenillas, i. (2012): planktonic foraminiferal and calcareous nannofossil biostratigraphy and magnetostratigraphy of the uppermost campanian and maastrichtian at zumaia, northern spain.– cretaceous research, 37, 100–126. doi: 10.1016/j.cretres.2012.03.011 pospichal, j.j. & bralower, t.j. (1992): calcareous nannofossils across the cretaceous/tertiary boundary, odp site 761, northwest australian margin.– proceedings of the ocean drilling program, scientific results, 122, 735–752. pospichal, j.j. & wise, s.w. (1990): calcareous nannofossils across the k/t boundary, odp hole 690c, maud rise, weddell sea.– proceedings of the ocean drilling program, scientific results, 113, 515–532. pospichal, j.j. (1996): calcareous nannoplankton mass extinction at the cretaceous/ tertiary boundary: an update.– in: ryder, g., fastovsky, d. & gartner, s. (eds.): the cretaceous–tertiary event and other catastrophes in earth history, geological society of america, special paper, 307, 335–360. reinhardt, p. (1965): neue familien für fossile kalkflagellaten (coccolithophoriden, coccolithineen).– monatsberichte der deutschen akademie der wissenschaften zu berlin, 7, 30–40. rigo de righi, m. & cortesini, a. (1959): anatolian basin. turkish gulf oil co., progress report, no. 1 (unpublished), ankara. romein, a.j.t. (1979): lineages in early paleogene calcareous nannoplankton.– utrecht micropaleontological bulletins, 22, 1–231. roth, p.h. (1978): calcareous nannoplankton biostratigraphy and oceanography of the northwestern atlantic ocean.– initial reports of the deep sea drilling project, 44, 731–760. sari, b., yildiz, a., korkmaz, t. & petrizzo, m.r. (2016): planktonic foraminifera and calcareous nannofossils record in the upper campanian–maastrichtian pelagic deposits of the malatya basin in the hekimhan area (nw malatya, eastern anatolia).– cretaceous research, 61, 91–107. doi: 10.1016/j.cretres.2015.12.012 schiller, j. (1930): coccolithineae.– in: rabenhorst, l. (ed.): kryptogamenflora von deutschland, österreich und der schweiz. akademische verlagsgesellschaft, leipzig, 89–267. schulte, p., alegret, l., arenillas, i., arz, j.a., barton, p.j., bown, p.r. bralower, t.j., christeson, g., claeys, p., cockell, c.s., collins, g.s., deutsch, a., goldin, t.j., goto, k., grajales-nishimura, j.m., grieve, r.a.f, gulick, s.p.s., johnson, k.r., kiessling, w., koeberl, c., kring, d.a., macleod, k.g., matsui, t., melosh, j., montanari, a., morgan, j.a., neal, c.r., nichols, d.j., norris, r.d., pierazzo, e., ravizza, g., rebolledo-vieyra, m., reimold, w.u., robin, e., salge, t., speijer, r.p., sweet, a.r., urrutia-fucugauchi, j., vajda, v., michael t., whalen, m.t. & willumsen, p.s. (2010): the chicxulub asteroid impact and mass extinction at the cretaceous–paleogene boundary.– science, 327, 1214–1218. doi: 10.1126/science.1177265 švabenicka, l. (1999): braarudosphaera-rich sediments in the turonian of the bohemian cretaceous basin, czech republic.– cretaceous research, 20, 773–782. doi: 10.1006/cres.1999.0182 şengor, a.m.c. (1985): geology: east asian tectonic collage.– nature, 318, 16–17. şengor, a.m.c. & yilmaz, y. (1981): tethyan evolution of turkey: a plate tectonic approach.– tectonophysics, 75, 181–241. g eo lo gi a c ro at ic a geologia croatica 75/3380 seymen, l. (1982): kaman dolayında kırşehir masifi’nin jeolojisi (in turkish).– unpubl. phd thesis, istanbul technical university, 164 p. shipboard scientific party (2004): site 1266. proceedings of the ocean drilling program.– initial reports, 208, 1–92. sissingh, w. (1977): biostratigraphy of cretaceous calcareous nannoplankton.– geologie en mijnbouw, 56, 37–65. smit, j. (1982): extinction and evolution of planktonic foraminifera after a major impact at the cretaceous/tertiary boundary. in: silver, l.t. & schultz, p.h. (eds.): geological implications of impacts of large asteroids and comets on the earth.– geological society of america, special paper, 190, 329–352. stradner, h. (1961): vorkommen von nannofossilien im mesozoikum und alttertiar.– erdöl-zeitung, 77, 77–88. tantawy, a. (2003): calcareous nannofossil biostratigraphy and paleoecology of the cretaceous–tertiary transition in the central eastern desert of egypt.– marine micropaleontology, 47, 323–356. doi: 10.1016/s0377-8398(02)00135-4 thibault, n. & gardin, s. (2007): the late maastrichtian nannofossil record of climate change in the south atlantic dsdp hole 525a.– marine micropaleontology, 65, 163–184. doi: 10.1016/j.marmicro.2007.07.004 thibault, n., husson, d., harlou, r., gardin, s., galbrun, b., huret, e. & minoletti, f. (2012): astronomical calibration of upper campanian–maastrichtian carbon isotope events and calcareous plankton biostratigraphy in the indian ocean (odp hole 762c): implications for the age of the campanian–maastrichtian boundary.– palaeogeography, palaeoclimatology, palaeoecology, 337–338, 52–71. doi: 10.1016/j.palaeo.2012.03.027 thibault, n., minoletti, f. & gardin, s. (2018): offsets in the early danian recovery phase in carbon isotopes: evidence from the biometrics and phylogeny of the cruciplacolithus lineage.– revue de micropaléontologie, 61, 207–221. doi: 10.1016/j.revmic.2018.09.002 thierstein, h.e. (1980): selective dissolution of late cretaceous and earliest tertiary calcareous nannofossils: experimental evidence.– cretaceous research, 1, 2, 165–176. doi: 10.1016/0195-6671(80)90023-3 tuysuz, o. & dellaloğlu, a.a. (1992): çankırı havzasının tektonik birlikleri ve jeolojik evrimi (in turkish).– türkiye 9, petrol kongresi, 333–349. van heck, s.e. & prins, b. (1987): a refined nannoplankton zonation for the danian of the central north sea.– abhandlungen der geologischen bundesanstalt, 39, 285– 303. varol, o. (1983): late cretaceous–paleocene calcareous nannofossils from the kokaksu section (zonguldak, northern turkey).– neues jahrbuch für geologie und paläontologie, abhandlungen, 166, 3, 431–460. varol, o. (1989): palaeocene calcareous nannofossil biostratigraphy.– in: crux, j.a. & van heck, s.e. (eds.): nannofossils and their applications. ellis horwood, chichester, 265–310. vekshina, v.n. (1959): coccolithophoridae of the maastrichtian deposits of the west siberian lowlands.– sniiggims, 2, 56–77. watkins, d.k. & self-trail, j.m. (2005): calcareous nannofossil evidence for the existence of the gulf stream during the late maastrichtian.– paleoceanography, 20, 3, 1–9. doi: 10.1029/2004pa001121 wei, w. (1988): a new technique for preparing quantitative nannofossil slides.– journal of paleontology, 62, 472–473. doi: 10.1017/s002233600005928x yildiz, a., karahasan, g., demi̇rcan, h. & toker, v. (2000): kalecik (ankara) güneydoğusu alt maastrihtiyen-paleosen biyostratigrafisi ve paleoekolojisi (in turkish).– yerbilimleri, 22, 247–259. 2022 | 75/2 | 223–233 | 9 figs. | 2 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the north-western part of croatia represents the southwestern margin of the pannonian basin system (pbs), and it is characterized by a high average geothermal gradient (49°c/km) and surface heat flow (76 mw/m2) (bošnjak et al., 1998). favourable geothermal conditions in this area are a consequence of the very shallow moho (mohorovičić seismic discontinuity), at between 25–28 km depth (aljinović & blašković, 1984; šumanovac et al., 2009; šumanovac et al., 2016). due to these favourable geological conditions, thermal springs occur in several locations, allowing the people who have inhabited this area throughout history, to use them for bathing, cooking and heating (šimunić, 2008). increased utilization of thermal aquifers has raised awareness of their protection and sustainability, and feasibility studies appeared in the early 19th century in which protection zones and rules on how to behave with thermal waters were defined (bancalari, 1868; rak, 1876; grudelj, 1890; gorjanović-kramberger, 1896). today, utilization of thermal aquifers varies from recreation, balneotherapy, space and district heating, greenhouse heating, fish farming, and directly as sanitary water, public water supply and electricity production. enhanced and sustainable utilization of this resource could significantly contribute to the forecasted geothermal development and achievement of croatia’s national renewable energy action plan (nreap) target. nreap pre current utilization and hydrochemical characteristics of geothermal aquifers in the bjelovar sub-depression tamara marković1,*, željka sladović2, dragutin domitrović3, igor karlović1 and ozren larva1 1 croatian geological survey, department of hydrogeology and engineering geology, 10 000 zagreb, croatia; (*corresponding author: tmarkovic@hgi-cgs.hr) 2 geoda, 10 000 zagreb, croatia 3 calida aqua, 10360 soblinec, croatia doi: 10.4154/gc.2022.21 abstract the bjelovar sub-depression is situated in the north-western part of croatia, on the southwestern margin of the pannonian basin system where favourable geothermal conditions exist. thermal waters are used for recreation, balneotherapy, space heating, directly as sanitary water and electricity production. geophysical, geological and borehole data were used to determine the types of geothermal reservoirs. in addition, several campaigns were conducted to sample geothermal waters from the daruvar spa, velika-1 and krečaves locations for isotope (δ18ο and δ2h) and physico-chemical (ec, t, ph, do, na+, k+, mg2+, nh4 +, ca2+, so4 2-, cl-, br-, f-, sio2 and h2s) analyses to determine their hydrochemical characteristics. two major types of geothermal reservoirs were determined: (i) ‘basement – bm’ reservoir, (ii) ‘basin fill – bf’ reservoir. the bm reservoir consists of palaeozoic and mesozoic sediments composed of: (i) fractured/karstified carbonate sediments and/or (ii) fractured/fissured crystalline/metamorphic rocks. the bf reservoirs are ‘lower pannonian’ and ‘upper pannonian’ sediments composed of coarse and fine-grained sand, sandstones and marls. the bm geothermal aquifers are the most important ones in the study area. the stable isotope δ2h and δ18o indicate that the monitored thermal waters have a meteoric origin, but without recent replenishment. monitored waters belong to mixed hydrochemical types, from na-clhco3 to na-hco3 types in the deep basin thermal waters and a camg-hco3 type in the thermal waters from shallower parts. the study area has great geothermal potential. the estimated total available thermal power from križevci, velika-1 and the daruvar spa is 70.5 mwt, but only 28 % of this thermal power is used. since the predominant activity in the study area is agriculture, the geothermal resources available could lead to modern agricultural development and consequently contribute to increasing the standard of living of the local population. however, additional geophysical, geological, hydrogeological and hydrochemical investigations at a number of new potential locations are required to estimate the total available geothermal resources. dicts a 39% renewable energy source (res) share in electricity production and 19.6% in heating and cooling from geothermal sources. in addition, geothermal waters in croatia contribute to economic growth through health and tourist resorts. two different laws regulate the usage of thermal waters, based on the method of utilization. if water is used for bottling, swimming and balneology, then the water act is applicable (official gazette 153/09, 63/11, 130/11, 56/13, 14/14). alternatively, if the water is used for heating and electricity production, the exploration and exploitation of hydrocarbons act has been applicable since 2018 (official gazette 52/18, 52/19). previously, the mining act was applicable (official gazette 56/13, 14/14). the sustainable use and management of geothermal resources is essential to ensure their long-term availability. the bjelovar sub-depression is located in the centre of northwestern croatia. it is a part of the drava depression and extends towards the sava depression, bordered by mountains on all sides. geothermal springs occur at the east – southeast edge of the subdepression. due to several hydrocarbon exploration campaigns in the 1970’s, 80’s and 90’s, numerous geothermal reservoirs were discovered. the aim of this paper is to hydrochemically characterize the geothermal aquifers that are utilized in the bjelovar sub-depression and to give an overview on potential areas suitable for their direct or indirect use. article history: manuscript received january 03, 2022 revised manuscript accepted may 04, 2022 available online june 23, 2022 keywords: geothermal aquifers, basin fill type, basement type, utilization, bjelovar sub-depression, croatia g eo lo gi a c ro at ic a geologia croatica 75/2224 2. materials and methods 2.1. study area the bjelovar sub-depression is bordered by the kalnik mt. to the northwest, bilogora mt. to the northeast, the papuk, ravna gora and psunj mts. to the east and southeast, and moslavačka mt. to the south (fig. 1). the local climate is categorized as part of the cfb group of the köppen–geiger classification system with an average annual air temperature of 10.9°c and average annual precipitation around 800 mm (zaninović et al., 2008). the study area comprises territories of three counties: the whole territory of bjelovarsko-bilogorska, around 50% of koprivničkokriževačka, and 10% of the zagrebačka county. moreover, these counties support tourism, agriculture, small and medium enterprises, and one of the many important factors which ensures future economic growth is a sustainable source of energy for consumption (heat and electricity). 2.2. data collection intensive geological data collection of the bjelovar sub-depression was carried out as part of the danube region leading geothermal energy project (darlinge, 2017–2019). in addition, chemical analyses of geothermal waters undertaken after the drilling of boreholes were used to improve the interpretation of the hydrochemical characteristics of geothermal waters. these data were provided by the ministry of economy and energy (mingo) in 2017. the geothermal waters from the daruvar, krečaves and ciglena locations were sampled between march 2018 to december 2019 in the scope of the darlinge and mamebio (a multiphasic approach for deciphering the microbial ecology and biotechnological potential of hot springs in croatia) projects for chemical and isotopic analyses. four sampling campaigns were carried out in daruvar and krečaves and two in ciglena. in križevci, it was technically impossible to take samples. therefore, hydrochemical interpretation was based on available chemical analyses done during the pumping test in 1990. in addition, one chemical analysis which was performed during dts tests after the drilling was used for ciglena. prior to sampling, the electrical conductivity (ec), ph, temperature (t) and dissolved oxygen content (o2) were determined using portable wtw electrodes. the total alkalinity was measured by titration with 1.6 n h2so4, using phenolphthalein and bromocresol green-methyl red as indicators. dissolved cations (na+, k+, mg2+, nh4 +, ca2+) and anions (so4 2-, cl-, br-, f-) were measured using ion chromatography on dionex ics-6000 dc, at the hydrochemical laboratory of the croatian geological survey. silica concentrations (sio2) and h2s were measured spectrophotometrically at the same laboratory using hach dr3900. the water quality analyses was checked for a cation–anion balance by measuring the relative deviation from charge balance (δmeq = 100 x (σmeq+ − σmeq−)/(σmeq+ + σmeq−) < ±5%) (mandel & shiftan, 1980; domenico & schwartz, 1990). the δ18ο and δ2h were determined using picarro l2130i (santa clara, usa) in the hydrochemical laboratory of the croatian geological survey. the instrument uses figure 1. the position of the study area with locations of the utilized (velika-1 and daruvar spa) and potential geothermal areas (krečaves, križevci, letičani, pavlovac, bačkovica, velika trnovitica, grubišno polje and dežanovac). g eologia c roatica marković et al.: current utilization and hydrochemical characteristics of geothermal aquifers in the bjelovar sub-depression 225 cavity ring-down spectroscopy (crds) technology (http:// www.picarro.com/technology/cavity_ring_down_spectroscopy). all measurements were checked with picarro’s standards (depleted −29.6 ± 0.2 δ18ο; −235 ± 1.8 δ2h; mid −20.6 ± 0.2 δ18ο; −159 ± 1.3 δ2h; zero 0.3 ± 0.2 δ18ο; 1.8 ± 0.9 δ2h), which were checked periodically against the international atomic energy agency (iaea) standards: vienna standard mean ocean water 2 (vsmow2) and standard light antarctic precipitation 2 (slap2). measurement precision was ± 0.3 ‰ for δ18ο and ± 1 ‰ for δ2h. 3. geological and hydrogeological settings of geothermal aquifers two major types of geothermal reservoirs were determined using the methodology developed in the project darlinge (rotár-szalkai et al., 2018): (i) ‘basement – bm’ reservoirs, (ii) ‘basin fill – bf’ reservoirs. 3.1. the basement reservoirs the bm reservoirs are palaeozoic and mesozoic sediments the formation of which was associated with the alpine–carpathian orogen, and represent the base of tertiary sediments. aquifers formed in this reservoir are the most important type in the study area. two types of geological strata represent reservoir rocks: (i) fractured/karstified carbonate sediments (dolomite; dolomite breccia – mainly triassic in age and limestones of triassic/cretaceous age) and/or (ii) fractured/fissured crystalline/metamorphic rocks (gabbro, schist, etc.). triassic dolomite is the most favourable type of geothermal reservoir in croatia due to its high permeability at some locations. miocene badenian sandstone and carbonate overlying triassic deposits are often associated with these aquifers. these aquifers are mainly low enthalpy systems (temperatures < 150°c), except for the eastern part of the bjelovar sub-depression (dolomite aquifers) which are high enthalpy (temperatures > 150°c). water temperatures range from 40 to 170°c. at the northwest, west and southeast margins of bjelovar subdepression, the bm reservoirs occur as outcrops. towards the sub-depression interior, the depth to the top of the bm varies from 100 to over 2000 m bsl. the depth mainly depends on the reservoir position in the sub-depression, because they are arranged into knappes along thrust sheets, dissected by strike-slip, normal and transcurrent faults, associated with the multiphase tectonic development of the basin (prelogović et al., 1998; saftić et al., 2003; malvić & velić, 2010; cvetković et al., 2019) (figs. 2-5). at present, the geothermal aquifer is utilized at two locations, and exploration is ongoing at a third location. the first location is situated in the middle of the study area, between the villages of patkovac and ciglena near the town of bjelovar, where the ina oil company drilled four boreholes during the 1990’s (ptk-1, vc-2, vc-1, vc-1a) (fig. 1). all boreholes reached the carbonate rocks (dolomite, dolomite breccia) of mesozoic age, where thermal water with a temperature of 175°c was observed at the bottom of vc-1 after the drilling. depth to the top of carbonate sediments (dolomite, dolomite breccia) varies from 2390 to 2314 m bsl, depending on borehole positions. the thickness of the carbonate sediments ranges from 500 to 1300 m. the dolomite and dolomite breccia are highly porous (~ 36%). during drill stem tests (dst), average values for vertical and horizontal permeability between 13.3 md and 350 md were determined (ina, 1990). due to the high permeability, the total yield of boreholes vc-1 and vc-1a is 114 l/s. the pressure in the aquifer is more than 300 bar. the second location is situated at the east – southeast edge of the sub-depression in daruvar town, where outcrops of dolomite exist. the upwelling of thermal waters occurs via a n-s strike transcurrent fault in the toplica river valley (figs. 2 and figure 2. schematic map of the depth to the top of the bm reservoir, based on gravity data. g eo lo gi a c ro at ic a geologia croatica 75/2226 5). the largest natural springs are the ivanovo vrelo, antunovo vrelo, and marijina vrela with temperatures ranging from 40 to 48°c. since the springs are situated in the river valley, alluvial deposits overlie the reservoir. such hydrogeological conditions enable the mixing of ‘cold’ alluvial water with accumulated geothermal water in the underlying aquifer, which is further enhanced during periods of increased geothermal water abstraction at wells and springs. since the spring zone is very dispersive, it is very difficult to determine its total discharge. measurements performed in 1962 by bać & herak determined that the total spring’s discharge is 7.5 l/s, then 10.5 l/s in 1983 by mraz, and the latest measurements in 2008 by larva et al. are 12 l/s. besides the natural springs, two boreholes exist, dar-1 drilled in 2009, and d-1 drilled a few years later for ensuring additional capacity. drilling reports of both boreholes are indicate that the thickness of the thermal aquifers (dolomite, limestone and dolomite breccia) is over 200 m. according to pumping tests and geophysical well-logging measurements (electrical logging, neutron natural radioactivity), which were conducted in the borehole dar-1 in 2009, the porosity in the area where aquifer has low permeability (it is not highly tectonised) is 10%, but in the very permeable area is 40% (crosco, 2009). the horizontal hydraulic permeability varies between 7.58 x 10-5 and 1.91 x 10-5 m/s (crosco, 2009). the maximum pumping yield is 40 l/s, but at this yield, lowering of the water level in the aquifer affects the discharge of the springs. the optimum pumping yield of the borehole dar-1 is 12.2 l/s and it is established as a steady state flow without endangerment of the spring’s discharges (larva et al., 2009). the optimum pumping yield of borehole d-1 is 2 l/s (larva et al., 2008). the third location is in križevci town, where borehole kža-1 was drilled in 1986. the borehole ended in palaeozoic rocks (slate, sandstone, slaty breccia-conglomerates) at a depth of 1496 m. in 1990, a 2-month pumping test was conducted and the water temperature during the test was 70°c, with an optimal pumping yield of 2 l/s (šarin, 1990). in 2008, a second phase of testing was conducted and the water temperature was 83.9°c (maljković & gudmundsson, 2017). unfortunately, the original testing report was unavailable, so the duration of pumping and pumping yield are not known. nevertheless, the hydrocarbon agency opened a tender procedure in september 2019 in order to select the most favourable bidder for exploration of the geothermal waters for energy purposes in the exploration area of “križevci” and in the beginning of 2020 gave concession for exploration of the geothermal waters for energy purposes. hopefully, this new exploration will provide a more conclusive answer about the water temperature. there are also several locations (pavljani, letičani, grubišno polje, velika trnovitica and dežanovac) where numerous geothermal aquifers were detected in bm crystalline/carbonate rocks, with water temperatures in the range of 68 to 170°c (fig. 1). 3.2. the basin fill reservoirs the bf reservoirs are a consequence of geological changes from the mid miocene when rifting occurred in the pbs (royden, 1988; horváth 1993; pavelić, 2001; malvić & velić, 2010). a deep basin was formed and offshore pelagic sediments developed in the basin interior, while coarse-grained brackish littoral sediments were deposited on the margins. as a result, a great lake was formed (lake pannon) which was gradually infilled with sediments during the late miocene and early pliocene (royden, 1988; horváth 1993; pavelić, 2001; saftić et al. 2003; malvić & velić, 2010; sebe et al. 2020). these sediments are today’s geothermal aquifers, known as the ‘pannonian’ sedimentary succession ‘lower pannonian’ (lp) and ‘upper pannonian’ (up) sediments (rman et al., 2016a; rman et al., 2016b; rotár-szalkai et al., 2017; nádor et al., 2020). the lp sediments consist of coarse material on the basin floor deposited by turbidity currents with subsequent sedimentation of silt and argillaceous marl on the slopes. as infilling of the lake progressed, figure 3. schematic cross section a-a’ of the križevci basin (according to fig. 2). g eologia c roatica marković et al.: current utilization and hydrochemical characteristics of geothermal aquifers in the bjelovar sub-depression 227 a shelf was formed and up sediments consisting of fine-grained materials were deposited, overlying the lp sediments. finally, alluvial plain sedimentation completed the infill of the lake basin (pavelić, 2001; malvić & velić, 2010; magyar et al., 2013) (figs. 2-5). unfortunately, this type of aquifer in the study area is not utilized and not explored so much as others. however, in the village of krečaves there is one old borehole that was drilled in the 1960’s during oil and gas exploration that detected thermal water. the favorable geothermal aquifer was reached at depth 638 m bsl. the borehole ended in the base of tertiary sediments, which consists of palaeozoic sediments, represented by slate and marble limestone. the measured temperature at the bottom after drilling was 56°c (ina, 1966). unfortunately, a dst test showed that there is no water in these sediments. in contrast, the bf sequence was productive and a dst test was conducted. the thickness of the geothermal aquifer in the borehole is 150 m. during the test, the outflowing yield was 1.5 l/s, the water temperature was 52°c, porosity ranged from 28 to 34%, and the average horizontal permeability was 380 md (ina, 1966). today’s outflow water temperature is around 45°c, and is dependent on water outflow duration, which in this case is the time of consumption by local people for showering. sometimes during the sampling campaign, the water temperature reached 47°c. the second unused borehole is in the village of veliko korenovo near the town of bjelovar, where the water temperature is 30°c (maljković & gudmundsson, 2017). figure 5. schematic cross section c-c’ of the ilova basin (according to fig. 2). figure 4. schematic cross section b-b’ of the east part of bjelovar sub-depression (according to fig. 2). g eo lo gi a c ro at ic a geologia croatica 75/2228 4. hydrochemical characteristics of the geothermal waters the mean values of the measured hydrochemical parameters in the thermal waters of monitored springs and boreholes are given in table 1. the highest ec value is the thermal water from velika-1, ciglena (23816 µs/cm), followed by water from borehole kža-1 (2500 µs/cm). ec values for thermal water from the daruvar spa on all three objects are very similar, and krečaves has slightly higher values than the spa waters. thermal water of velika-1, ciglena contains a high amount of dissolved co2 (30 m3/ m3) comprising 99.5% of gas, about 59 ppm h2s and 24.4 ppm nh4 +. also, the water contains oil (ina, 1990). krečaves contains 2.4 ppm h2s and 8.5 ppm nh4 +. thermal waters of the daruvar spa have much lower concentrations of h2s and nh4 +. the highest concentrations of na+, cl-, k+, and so4 2are present in thermal water from ciglena, followed by water from križevci, krečaves and daruvar spa. fis observed in all the sampled waters, while bris only observed in the waters of ciglena. according to the chemical composition, thermal waters of daruvar spa belong to camg-hco3 type, velika-1, ciglena belongs to na-clhco3 type, krečaves to na-hco3 type, and borehole kža-1 belongs to na-hco3so4cl type (fig. 6). hydrochemical types, as recognized from water chemistry data, are a consequence of the chemistry of the recharging water and water–aquifer matrix interactions (e.g. cation exchange), as well as the groundwater residence time within the aquifer. two general processes contribute solutes to thermal waters: carbonate dissolution and silicate weathering (domenico & schwartz, 1990). from fig. 7 it can be observed that the water chemistry of ciglena and daruvar spa are primarily controlled by the dissolution of dolomite, because the mg2+/ca2+ ratios are above 0.33. however, according to the chemical composition of thermal waters from velika-1, ciglena, the prevailing cation is na+, indicating that other geochemical processes are present in the thermal aquifer or the origin of the water is different. on the bivariate mixing diagram of na+-normalized ca2+ versus na+-normalized mg2+ (fig. 8a), the sample falls between the silicate weathering and carbonate dissolution domains, but slightly closer to the latter, indicating that carbonate dissolution is dominant. the influence of cation exchange was evaluated by an equivalent bivariate plot of corrected bivalent cations versus corrected na+ (fig. 8b). concentrations of bivalent cations (ca2+ and mg2+) that may have been involved in exchange reactions were corrected by subtracting equivalent concentrations of the associated anions (hco3 and table 1. mean values of the measured hydrochemical parameters. location no. of samples ec (ms/cm) t (°c) ph hco3 – (mg/l) ca2+ (mg/l) mg2+ (mg/l) na+ (mg/l) k+ (mg/l) cl– (mg/l) so4 2– (mg/l) sio2 (mg/l) nh4 + (mg/l) h2s (mg/l) f– (mg/l) br– (mg/l) d18o (o/oo) d2h (o/oo) krečaves 4 734 45.0 8.1 590 4.2 0.5 198.6 3.3 5.4 35.7 31.2 8.5 2.4 1.0 <0.1 -11.42 -79.39 ivanovo vrelo 4 616 43.4 7.2 326 73.0 24.0 13.8 3.7 1.5 52.0 39.7 0.2 0.4 0.5 <0.1 -10.20 -71.30 antunovo vrelo 4 647 47.5 6.9 326 75.1 23.7 13.6 3.7 1.6 52.1 39.8 0.2 0.4 0.5 <0.1 -10.34 -71.20 borehole d-1 4 653 44.3 6.9 330 76.1 24.7 13.2 3.5 1.7 50.3 39.7 0.3 0.4 0.5 <0.1 -10.25 -70.76 velika-1, ciglena 3 23816 150.7 6.8 2450 280.5 65.0 8436.0 485.3 12496.4 117.0 256.5 24.5 59.0 4.8 55.2 5.05 -15.20 borehole kža-1 1 2500 70.0 7.2 470 130.0 30.0 740.0 40.0 260.0 355.0 figure 6. piper diagram of mean values of chemical major components in sampled thermal waters. g eologia c roatica marković et al.: current utilization and hydrochemical characteristics of geothermal aquifers in the bjelovar sub-depression 229 so4 2-) that would derive from other processes (e.g. carbonate dissolution or silicate weathering). similarly, na+ that may derive from the aquifer matrix can be accounted for by assuming that na+ contributions of meteoric origin would be balanced by equivalent concentrations of cl(mclean & jankowski, 2000). for active cation exchange taking place in the aquifer, the slope of this bivariate plot should be -1 (i.e. y = -x) (jankowski et al., 1998). also, on the bivariate plot of (ca2+ + mg2+) (hco3 + so4 2-) against (na+ cl-) (fig. 8b) samples of both locations are on the line y = -x, which indicates active cation exchange processes within the aquifer. these geochemical processes have been detected before in croatian carbonate thermal aquifers (marković et al., 2015). however, fig. 8a shows that the chemical composition of thermal waters from krečaves and križevci are controlled by silicate weathering. although in the križevci area, the aquifer is a ‘’silicate’’ type of aquifer as in krečaves, the chemical composition is different because the aquifer matrix contains a high amount of sulfide and chlorite minerals. in the past, mining of lead, zinc and silver ores occurred on kalnik mt., which is the recharge area of the thermal aquifer. the na/cl ratio of the thermal waters from velika-1, ciglena is <1 and for others is >10, which indicates a marine origin for ciglena and a non-marine origin for the rest of the waters. the br/cl ratio of the thermal waters from velika-1, ciglena is higher than that for sea water. this water also contains traces of oil. in all the observed thermal waters, measured stable isotope ratios of δ2h and δ18o are distributed around the local meteoric water line (lmwl) bjelovar (hunjak et al., 2013) indicating meteoric origin (fig. 9). the stable isotope ratios δ2h and δ18o in thermal waters from velika-1, ciglena are slightly shifted to the right from the lmwl at bjelovar because the values are enriched. the enrichment in δ18o is a consequence of geothermal exchange between the fluid and host rock at high pressures and temperatures, a phenomenon that has been observed elsewhere in the high temperature deep groundwater systems in the world (cartwright, 2002, 2010; arnorsson 2000; rman, 2016). measured ratios in the thermal waters of daruvar spa area lie on the lmwl of bjelovar (marković & larva, 2012), while values from thermal water krečaves are slightly above the bjelovar lmwl indicating depletion. depletion of stable isotopes was characteristic for colder periods in the pleistocene and such depleted values were observed in the thermal waters of the pannonian basin in slovenia and hungary (szőcs et al., 2013; rman, 2016; rman et al., 2016a). thermal water from ciglena does not contain 14c, it is inactive, indicating that the water is very old. in contrast, thermal waters from daruvar spa still contain 14c and the thermal water age was calculated using 13c correction which was 15.000 years (larva et al., 2008). in addition, borović et al. (2019) in the numerical model of the daruvar spa thermal aquifer established that the recharge area is from the east papuk mt. 5. utilization and potential of geothermal aquifers thermal waters in daruvar town have been utilized since ancient roman times. in 1772, count janković started building around springs, hoping that the town would become a place of healing, leisure and a recreation centre which was rapidly realised. nowadays, thermal waters from ivanovo vrelo, antunovo vrelo and borehole d-1 are used only for recreation, balneotherapy and sanitary water in the complex of the special hospital for medical rehabilitation and thermal water park aquae balissae. considering the amount of thermal water which can be sustainably used from two boreholes and three major springs, the available thermal power is 4.6 mwt. at the moment, only 13 % of this available thermal power is utilized (table 2). the geothermal power plant “velika 1” was recently built as a 35-million-euro investment by turkish mb holding, starting full-time operation in march 2019 after initial operational tests. the power plant uses old ina wells as producers and injectors, figure 7. molar ratios of magnesium and calcium ions in the thermal waters of velika-1, ciglena and daruvar spa. g eo lo gi a c ro at ic a geologia croatica 75/2230 and utilizes the heat of geothermal water to generate electricity by the organic rankine cycle (orc) process, using isobutane as the working fluid rotating the turbine. geothermal water is produced by two production wells (vc-1 and vc-1a) at the wellhead temperature of 166°c and wellhead pressure of 30 bar. by transferring its heat to the working fluid, the water is cooled down to 75°c and is then reinjected into the same geothermal reservoir through two remote injection wells (vc-2 and ptk-1). at maximum gross power of 16.5 mwe, this is currently the largest orc geothermal power plant in continental europe. with constant net delivery of 10 mwe into the medium voltage 35 kv grid, it generates approx. 7 gwh of electrical energy per month, which is the equivalent of the average electricity consumption of 29.000 croatian households. the available thermal power for this location is 64.9 mwt. in september 2019, the hydrocarbon agency opened a tender procedure in order to select the most favourable bidder for exploration of geothermal waters for energy purposes in the exploration area “križevci”. according to eihp study (maljko vić & gudmundsson, 2017), the available thermal power from figure 8. a) bivariate mixing diagram of na+-normalized ca2+ versus na+-normalized mg2+ in sampled thermal waters; b) bivariate plot of (ca2+ + mg2+) (hco3 + so4 2-) against (na+ cl-) in sampled thermal waters. a) b) g eologia c roatica marković et al.: current utilization and hydrochemical characteristics of geothermal aquifers in the bjelovar sub-depression 231 kža-1 was estimated between 0.75 and 1 mwt (table 2) and water is feasible for the heating of three schools, a gymnasium with swimming pool and greenhouses as part of the agriculture department of the high school and college of agriculture. 6. conclusion two major types of geothermal reservoirs in the study area were determined using geophysical, geological and borehole data: (i) ‘basement – bm’ reservoirs which are palaeozoic and mesozoic fractured/karstified carbonate sediments and/or crystalline/metamorphic rocks, (ii) ‘basin fill – bf’ reservoirs which are ‘lower pannonian’ and ‘upper pannonian’ sediments composed of coarse and fine-grained sand, sandstones and marls. the bm geothermal aquifers are the most important ones in the study area, with the largest geothermal potential which has resulted in the first geothermal power plant in croatia to be built there. sampled thermal waters from velika-1, ciglena belong to the na-clhco3 hydrochemical type, as a consequence of mixing different waters (oil waters, brines and palaeometeoric water) and water-rock interaction. thermal waters from daruvar spa belong to the camg-hco3 type and represent the typical type of dolomite/limestone thermal aquifers. sampled waters from krečaves belong to the na-hco3 type as a consequence of silicate minerals and water-rock interaction. at the križevci location, thermal waters belong to the na-hco3so4cl type as a consequence of silicate and sulfide mineral weathering. the stable isotope ratios δ2h and δ18o indicate that monitored thermal waters have a meteoric origin without recent replenishment. the study area has great geothermal potential for electricity production, but even more for low enthalpy usage in district heating, industry, etc. at locations with future geothermal potential it will be necessary to conduct additional geophysical, geological, hydrogeological and hydrochemical investigations to determine the spatial distribution, thickness, hydrochemical properties and to determine their available thermal power. calculated total available thermal power for križevci, velika-1 and daruvar spa is 70.5 mwt and only 28 % of this thermal power is used. agrogeothermal use of lower temperature waters (up to 80° c) in the bjelovar region also has significant potential because it could lead to the modern development of agriculture and consequently contribute to increasing the standard of living of the local population. it is noticeable that the interest of investors for geothermal projects in croatia is growing, and hopefully this utilization of geothermal resources – especially with regards to strong and optimistic targets of the new green deal – will blossom in the forthcoming years. acknowledgement the paper is part of the darlinge project, co-funded by the european regional development fund (1612249.99 €) and by the instrument for pre-accession assistance ii (534646.6 €) under grant agreement no. dtp1-099-3.2. and mamebio project, cofunded by the croatian science foundation (hrzz) pzs-201902-7373. in addition, the knowledge gained through the geotwinn project that has received funding from the european union’s horizon 2020 research and innovation programme under grant agreement no. 809943 and contributed to the chemical and isotopic data interpretation. we would like to thank all users for support during the sampling campaigns. table 2. the available and utilized thermal power at križevci, velika-1 and daruvar spa locations. location available thermal power (mwt) utilized thermal power (mwt) križevci 0.75 – 1* – velika-1 64.9 19 daruvar spa 4.6 0.6 *according maljković & gudmundsson (2017) figure 9. relationship between isotopic ratios of d18o and d2h in the sampled thermal waters. g eo lo gi a c ro at ic a geologia croatica 75/2232 references aljinović, b. & blašković, i. (1984): comparison of sediment basis and the mohorovičić discontinuity in the coastal area of yugoslavia.− nafta, zagreb, 35, 65–71. arnorsson, s. (2000): isotopic and chemical techniques in geothermal exploration, development and use: sampling methods, data handling, interpretation.– vienna: iaea, 351 p. bać, j. & herak, m. (1962): prijedlog za određivanje užih i širih zaštitnih zona termomineralnih izvora u hrvatskoj [proposal for determination of narrower and wider protection zones of thermomineral springs in croatia – in croatian].– unpubl. technical report, archive of the croatian geological survey. bancalari, d. (1868): das mineralbad krapina toeplitz in croatien. krapina spa and its warm springs and baths.– vienna (in german), 85 p. borović, s., pola, m., bačani, a. & urumović, k. (2019): constraining the recharge area of a hydrothermal system in fractured carbonates by numerical modelling.− geothermics, 82, 128–149. doi: 10.1016/j.geothermics.2019.05.017 bošnjak, r., čubrić. s., golub, m., grabovski, k., jelić, k., kolin, i., košćak, s., kulenović, i., miočev, d., pravica, z., rajković, d., salopek, b., sečen, j. & stančić, l. (1998): geoen – program korištenja geotermalne energije [programme of geothermal energy utilization – in croatian].– energy institute hrvoje požar, zagreb, 123 p. cartwright, i., weaver, t., tweed, s., ahearne, d., cooper, m., czapnik, k. & tranter, j. (2002): stable isotope geochemistry of cold co2-bearing mineral spring waters, daylesford, victoria, australia: sources of gas and water and links with waning volcanism.− chem. geol. 185, 71–91. doi: 10.1016/ s0009-2541(01)00397-7 cartwright, i., weaver, t.r., simmons, c.t., fifield, l.k., lawrence, c.r., chisari, r. & varley, s. (2010): physical hydrogeology and environmental isotopes to constrain the age, origins and stability of a low-salinity groundwater lens formed by periodic river recharge: murray basin, australia.− j. hydrol., 380, 203–221. doi: 10.1016/j.jhydrol.2009.11.001 crosco (2009): izvještaj o bušenju bušotine dar-1 [drilling report of the borehole dar-1 – in croatian].– unpublished, fund of professional documentation of crosco, zagreb. cvetković, m., matoš, b., rukavina, d., kolenković močilac, i., saftić, b., baketarić, t., baketarić, m., vuić, i., stopar, a., jarić, a. & paškov, t. (2019): geoenergy potential of the croatian part of pannonian basin: insights from the reconstruction of the pre-neogene basement unconformity.− j. maps, 15/2, 651–661. doi: 10.1080/17445647.2019.1645052 darlinge (2017-2019): danube region leading geothermal energy project, http:// www.interreg-danube.eu/approved-projects/darlinge domenico, p.a. & schwartz, f.w. (1990): physical and chemical hydrogeology.– john willey and sons, new york, 824 p. gorjanović-kramberger, d. (1896): geology and hydrogeology of the area of stubičke toplice. zagreb. grudelj, a. (1890): zaštitne zone termalnih izvora i kupelji vraždinskih toplica u varaždinskoj županiji na putu prema novom marofu [protection zones of the bathing area of the thermal springs in varaždinske toplice in the varaždin county towards novi marof – in croatian]. zagreb, 25p. horváth, f. (1993): towards a mechanical model for the formation of the pannonian basin.– tectonophysics, 225, 333–358. doi: 10.1016/0040-1951(93)90126-5 hunjak, t., lutz, h.o. & roller-lutz, z. (2013): stable isotope composition of the meteoric precipitation in croatia.– isot. environ. health stud., 49/3, 336–45. doi: 10.1080/10256016.2013.816697 ina (1966): geološki i dts izvještaj bušotine ze-1 [geological and dts reports of well ze-1 – in croatian].– unpublished, fund of professional documentation of ina, zagreb provided by ministry of economy and energy, 25 p. ina (1990): geološki i dts izvještaj bušotina vc-1 i vc-1a [geological and dts reports of wells vc-1 and vc-1a – in croatian].– unpublished, fund of professional documentation of ina, zagreb provided by ministry of economy and energy 50 p. jankowski, j., acworth, r.i & shekarforoush, s. (1998): reverse ion exchange in deeply weathered porphyritic dacite fractured aquifer system, yass, new south wales, australia.– in: arehart, g.b. & hulston, j.r. (eds.): proceedings of the 9th international symposium on water-rock interaction, taupo, new zealand, 30 march 3 april, 1998. rotterdam, a.a. balkema, 243–246. larva, o., mraz, v. & marković, t. (2008): daruvarske toplice elaborat utvrđivanja eksploatacijske izdašnosti ivanovog vrela i objekta š-3 [daruvarske spa study for determining the exploitation yields of ivanovo vrelo and š-3 – in croatian].– unpubl. technical report, archive of the croatian geological survey, 10 p. larva, o., mraz, v. & marković, t. (2009): hidrogeološki nadzor tijekom bušenja, ugradnje, čišćenja i pokusnog crpljenja istražno – eksploatacijke bušotine dar-1 u daruvaru [hydrogeological monitoring during drilling, installation, cleaning and experimental pumping of the exploration-exploitation well dar-1 in daruvar – in croatian].– unpubl. technical report, archive of the croatian geological survey, 12 p. magyar, i., radivojević, d., sztanó, o., synak, r., ujszászi, k. & pócsik, m. (2013): progradation of the paleo-danube shelf margin across the pannonian basin during the late miocene and early pliocene.– glob. planet. change, 103, 168–173. doi: 10.1016/j.gloplacha.2012.06.007 maljković, d. & gudmundsson j.r. (eds.) (2017): geothermal energy utilisation potential in croatia by sanja živković (eihp), rudolf van hemert (eihp), dražen tumara (eihp), karmen stupin (eihp), j. rúnar magnússon (efla consulting engineers, iceland), heimir hjartarson (efla consulting engineers, iceland), jill robinson haizlip (geologica geothermal group), manon m. stöver, (geologica geothermal group), eihp, zagreb, 57 p. malvić, t. & velić, j. (2010): relations between effective thickness, gas production and porosity in heterogeneous reservoirs: an example from the molve field, croatian pannonian basin.– pet. geosci., 16, 41–51. doi: 10.1144/1354079309-722 mandel, s. & shiftan, z.l. (1980): groundwater resources: investigation and development.– academic press, new york, 269 p. marković, t. & larva, o. (2012): hydrochemistry of thermal water in daruvar area.– in: stevanović, z. (ed.): proceedings of 14th serbian symposium of hydrogeology with international participation, university of belgrade, mining and geology faculty, belgrade, 187–191. marković, t., borović, s. & larva, o. (2015): geochemical characteristics of thermal waters of hrvatsko zagorje.− geol. croat., 68/1, 67–77. doi: 10.4154/ gc.2015.05 mclean, w. & jankowski, j. (2000): groundwater quality and sustainability in an alluvial aquifer, australia.– in: sililo, a. (ed.): xxx iah congress on groundwater: past achievements and future challenges. a.a. balkema, rotterdam. mraz, v. (1983): izvještaj o hidrogeološkim istražnim radovima na području daruvarskih toplica ii. faza [report on hydrogeological exploration works in the area of daruvar spa ii phase – in croatian].– unpubl. technical report, archive of the croatian geological survey, 13 p. nádor, a., sebess-zilahi, l., rotár-szalkai, á., gulyás, á. & marković, t. (2020): new methods of geothermal potential assessment in the pannonian basin.− neth. j. geosci., 98, e10. doi: 10.1017/njg.2019.7 official gazette 153/09, 63/11, 130/11, 56/13, 14/14.– water act. official gazette 52/18, 52/19.– exploration and exploitation of hydrocarbons act. official gazette 56/13, 14/14.– mining act. pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.− basin res., 13, 359–376. doi: 10.1046/j.0950-091x.2001.00155.x prelogović, e., saftić, b., kuk, v., velić, j., dragaš, m. & lučić, d. (1998): tectonic activity in the croatian part of the pannonian basin.− tectonophysics, 297, 283–293. doi: 10.1016/s0040-1951(98)00173-5 rak, a. (1876): krapinske toplice [krapina spa – in croatian].– vienna 45 p. rman, n. (2016): hydrogeochemical and isotopic tracers for identification of seasonal and long-term over-exploitation of the pleistocene thermal waters.− environ. monit. assess., 188(4), 242. doi: 10.1007/s10661-016-5250-2 rman, n., gál, n., marcin, d., weilbold, j., schubert, g., lapanje, a., rajver, d., benková, k. & nádor, a. (2016a): potentials of transboundary thermal water resources in the western part of the pannonian basin.− geothermics, 55, 88–98. doi: 10.1016/j.geothermics.2015.01.013 rman, n., lapanje, a., prestor, j. & sullivan, m.j.o. (2016b): mitigating depletion of a porous geothermal aquifer in the pannonian sedimentary basin.− environ. earth sci., 75, 723. doi: 10.1007/s12665-016-5634-1 rotár-szalkai, á., maros, gy., bereczki, l., markos, l., babinszki, e., zilahi-sebess, l., gulyás, á., kun, é., szőcs, t., kerékgyártó, t., nádor, a., rajver, d., lapanje, a., šram, d., marković, t., vranješ, a., farnoaga, r., samardžić, n., hrvatović, h., skopljak, f. & jolović, b. (2018): identification, ranking and characterization of potential geothermal reservoirs.− report of the darlinge project, 82 p. available at www.interreg-danube.eu/approved-projects/darlinge/outputs. rotár-szalkai, á., nádor, a., szőcs, t., maros, g., goetzl, g. & zekiri, f. (2017): outline and joint characterization of transboundary geothermal reservoirs at the western part of the pannonian basin.− geothermics, 70, 1–16. doi: 10.1016/j.geothermics.2017.05.005 royden, l. (1988): late cenozoic tectonics of the pannonian basin system.– in: royden, l. h. & horváth, f. (eds.): the pannonian basin (memoir 45), american association of petroleum geologists, 27–48. saftić, b., velić, j., sztano, o., juhasz, g. & ivković, ž. (2003): tertiary subsurface facies, source rocks and hydrocarbon reservoirs in the sw part of the pannonian basin (northern croatia and south-western hungary).− geol. croat., 56/1, 101–122. doi: 10.4154/232 sebe, k., kovačić, m., magyar, i., krizmanić, k., špelić, m., bigunac, d., sütő-szentai, m., kovács, á., szuromi-korecz, a., bakrač, k., hajek-tadesse, v., troskot-čorbić, t. & sztanó, o. (2020): corg eologia c roatica marković et al.: current utilization and hydrochemical characteristics of geothermal aquifers in the bjelovar sub-depression 233 relation of upper miocene-pliocene lake pannon deposits across the drava basin, croatia and hungary.− geol. croat., 73/3, 177–195. doi: 10.4154/gc.2020.12 szőcs, t., rman, n., süveges, m., palcsu, l., tóth, g. & lapanje, a. (2013): the application of isotope and chemical analyses in managing transboundary groundwater resources.− appl. geochemistry, 32, 95–107. doi: 10.1016/j.apgeochem.2012.10.006 šarin, a. (1990): tehnički izvještaj o pokusnom crpljenju termomineralne bušotine kža-1 u križevcima [technical report on the pumping test at the well kža-1 in križevci – in croatian].– technical report, archive of the croatian geological survey. šimunić, a. (ed) (2008): geotermalne i mineralne vode rh [geothermal and mineral waters of the republic of croatia – in croatian].– croatian geological survey, zagreb, 343 p. šumanovac, f., hegedűs, e., orešković, j., kolar, s., kovács, a.c., dudjak, d. & kovács, i.j. (2016): passive seismic experiment and receiver functions analysis to determine crustal structure at the contact of the northern dinarides and southwestern pannonian basin.− geophys. j. int., 205, 3, 1420–1436. doi: 10.1093/gji/ggw101 šumanovac, f., orešković, j., grad, m. & alp 2002 working group (2009): crustal structure at the contact of the dinarides and pannonian basin based on 2-d seismic and gravity interpretation of the alp07 profile in the alp 2002 experiment.− geophys. j. int., 179, 615–633. doi: 10.1111/j.1365-246x.2009. 04288.x zaninović, k., gajić-čapka, m. & perčec tadić, m. (2008): klimatski atlas hrvatske. climate atlas of croatia: 1961.–1990, 1971–2000.− državni hidrometeorološki zavod. zagreb, croatia, 200 p. 2022 | 75/2 | 189–198 | 4 figs. | 1 tab. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction abnormalities and malformations provide a unique insight into the palaeobiology and regenerative abilities of animals, including trilobites (babcock, 2003). the fossil record of trilobites in par­ ticular contains numerous examples of morphological abnormali­ ties that have been variously interpreted. owen (1985) reviewed all earlier documented trilobitic abnormalities and suggested three types: injuries, pathologies, and teratologies. owen (1985), healed injury in a nektobenthic trilobite: “octopus-like” predatory style in middle ordovician? oldřich fatka1, petr budil2 and radek mikuláš3 1 charles university, institute of geology and palaeontology, albertov 6, cz–128 43, prague 2, czech republic; (fatka@natur.cuni.cz) 2 czech geological survey, klárov 3, 118 21 prague 1, czech republic; (petr.budil@geology.cz) 3 academy of sciences of the czech republic, institute of geology, v.v.i., rozvojová 269, cz–165 02 praha 6 – lysolaje, czech republic; (mikulas@gli.cas.cz) doi: 10.4154/gc.2022.17 abstract the lower paleozoic sediments of the barrandian area are globally renowned as a classical example of well-preserved skeletal marine fauna, including abundant remains of trilobites. seve ral tens of morphologically anomalous exoskeletons of trilobites have been collected and documented from cambrian to devonian clastic sediments and carbonates. one of them, an exceptionally well preserved, articulated and partly enrolled exoskeleton of the ordovician nektobenthic trilobite parabarrandia bohemica (novák, 1884) exhibits a prominent palaeopathological anomaly in its pygidium. we interpret this anomaly as a healed traumatic injury and attribute this damage to a failed predatory attack. the subsequently healed injury is classified as the ichnogenus oichnus bromley, 1981. the structure on the pygidium is strongly reminiscent of injuries caused by octopods and a large cephalopod is proposed as a potential durophagous predator responsible for the herein described trilobite injury. however, an attack from an unknown arthropod while the trilobite was in a soft-shelled stage cannot be excluded. babcock (1993, 2003, 2007), fatka et al. (2015), bicknell & paterson (2018), bicknell & pates (2020) concluded that the majority of trilobite abnormalities represent healed injury. the general rarity of repaired injuries in trilobites suggests that predatory attacks (particularly on soft­shelled individuals) were often successfully executed (bicknell & paterson, 2018). in the barrandian area, the study of anomalous trilobite exo­ skeletons has a long tradition. barrande (1852, pl. 9, fig. 19) 1. fatka 2. šimunek 3. kurtanjek 4. marković 5. ratković 6. schnaider 7. borojević-šostarić article history: manuscript received december 07, 2020 revised manuscript accepted march 16, 2022 available online june 23, 2022 keywords: trace fossils, palaeopathology, praedichnia, barrandian area, prague basin, czech republic figure 1. location of the prague basin. a. map of europe showing the czech republic, b. map of the czech republic with the location of the prague basin. the studied specimen comes from the šárka locality, c. detailed geographical position of the named localities within the prague basin. localities: 1 – osek, 2 – čilina, 3 – svatá dobrotivá, 4 – králův dvůr, 5 – drabov, 6 – brdatka, 7 – veselá, 8 – malé přílepy, 9 – libuš, 10 – hodkovičky, 11 – michle, 12 – spořilov, 13 – jinonice, 14 – šárka, 15 – hloubětín and štěrboholy. g eo lo gi a c ro at ic a geologia croatica 75/2190 ta bl e 1. s um m ar y of tr ilo bi te s w ith a bn or m al iti es d oc um en te d fro m th e o rd ov ic ia n of th e ba rr an di an a re a sp ec ie s a no m al y / c ul pr it of th e at ta ck co nt rib ut io n st ra tig ra ph y / l oc al ity (f ig s 1 a nd 2 ) pr ic yc lo py ge b in od os a bi no do sa (s a lt er , 1 85 9) la rg e an om al ou s e ye / cu lp rit u nk no w n m a re k (1 96 1, p l. 2, fi g. 8 ), kr a ft (1 97 2, p l. 3, fi g. 6 ), br u th a n so vá (2 00 4, te xt -fi g. 8 g ) m id dl ela te d ar riw ili an (š ár ka f or m at io n) / o se k or pr ah a – li bu š l oc al ity as ap he llu s d es id er at us (b a rr a n d e, 1 87 2) ex te ns iv e in ju ry o f p yg id iu m / su pp os ed ly n au til oi d ce ph al op od šn a jd r (1 98 0) m id dl ela te d ar riw ili an (š ár ka f or m at io n) / un kn ow n ar ei as pi s b ar ra nd ei (n o vá k in p er n er , 1 91 8) sh or te ne d an d he al ed le ft p le ur a of th e 9t h th or ac ic se gm en t / c ul pr it un kn ow n bu d il e t a l. (2 01 0, p . 1 00 -1 02 , fi g. 3 a -c ) m id dl ela te d ar riw ili an (š ár ka f or m at io n) / o se k lo ca lit y pa ra ba rr an di a bo he m ic a (n o vá k, 1 88 4) py gi di um b ea rin g tw o pu nc tu re s s ur ro un de d by sw el lin g / l ar ge c ep ha lo po d or u nk no w n ar th ro po d th is st ud y m id dl ela te d ar riw ili an (š ár ka f or m at io n) / pr ah a – šá rk a lo ca lit y eo ha rp es b en ig ne ns is (b a rr a n d e, 1 87 2) te ra to lo gi ca l r ig ht m ar gi n of b rim / cu lp rit u nk no w n pr a n tl & p ři by l (1 95 4, p l. 10 , fi g. 3 ) la te d ar riw ili an – e ar ly s an db ia n (d ob ro tiv á fo rm at io n) / sv at á d ob ro tiv á lo ca lit y pl ac op ar ia zi pp ei (b o ec k, 1 82 7) an om al ou s t hi rd to fi ft h rig ht p le ur ae o f t ho ra x / c ul pr it un kn ow n šn a jd r (1 97 9b , fi g. 1 ) la te d ar riw ili an – e ar ly s an db ia n (d ob ro tiv á fo rm at io n) / m al é př íle py lo ca lit y pl ac op ar ia zi pp ei (b o ec k, 1 82 7) an om al ou s g la be lla r l ob e l2 / cu lp rit u nk no w n šn a jd r (1 97 9b , fi gs 2 , 3 ) la te d ar riw ili an – e ar ly s an db ia n (d ob ro tiv á fo rm at io n) / m al é př íle py lo ca lit y pl ac op ar ia zi pp ei (b o ec k, 1 82 7) an om al ou s g la be lla r l ob e / c ul pr it un kn ow n šn a jd r (1 97 9b , fi g. 4 ) la te d ar riw ili an – e ar ly s an db ia n (d ob ro tiv á fo rm at io n) / pr ah a – h od ko vi čk y lo ca lit y d al m an iti na so ci al is (b a rr a n d e, 1 84 6) fir st to th ird p le ur ae a t t he ri gh t s id e of p yg id iu m / cu lp rit u nk no w n šn a jd r (1 95 6, p l. 4, fi g. 2 ) m id dl e sa nd bi an (l et ná f or m at io n) / či lin a at ro ky ca ny lo ca lit y d al m an iti na so ci al is (b a rr a n d e, 1 84 6) an om al ou s r ig ht fi xi ge na / du ro ph ag ou s p re da to r šn a jd r (1 99 0, p . 5 859 ) m id dl e sa nd bi an (l et ná f or m at io n) / be ro un , e xa ct lo ca lit y un kn ow n d al m an iti na so ci al is (b a rr a n d e, 1 84 6) an om al ou s p yg id ia l a xi s a nd o f b ot h rig ht a nd le ft p le ur ae / du ro ph ag ou s p re da to r šn a jd r (1 99 0, p . 6 061 ) m id dl e sa nd bi an (l et ná f or m at io n) / be ro un , e xa ct lo ca lit y un kn ow n d al m an iti na so ci al is (b a rr a n d e, 1 84 6) an om al ou s t hr ee a nt er io r p le ur ae a t t he ri gh t s id e of p yg id iu m / cu lp rit u nk no w n vo ká č (1 99 6, p . 2 0, fi g. 5 ) m id dl e sa nd bi an (l et ná f or m at io n) / d ra bo v ne ar be ro un lo ca lit y d al m an iti na so ci al is (b a rr a n d e, 1 84 6) an om al ou s t hr ee a nt er io r p le ur ae a t t he le ft si de o f p yg id iu m / cu lp rit u nk no w n vo ká č (1 99 6, p . 2 0, fi g. 6 ) m id dl e sa nd bi an (l et ná f or m at io n) / ve se lá n ea r be ro un lo ca lit y d al m an iti na so ci al is (b a rr a n d e, 1 84 6) de fo rm ed ri gh t fi xi ge na a nd li br ig en a of c ep ha lo n / c ul pr it un kn ow n vo ká č (1 99 6, p . 2 0, fi g. 7 ) m id dl e sa nd bi an (l et ná f or m at io n) / ve se lá n ea r be ro un lo ca lit y d al m an iti na so ci al is (b a rr a n d e, 1 84 6) re ge ne ra te d vi su al su rf ac e of th e le ft ey e, th e pa lp eb ra l l ob e, th e lib rig en a an d th e fix ig en a / s up po se dl y la rg e ar th ro po d or n au til oi d ce ph al op od fa tk a e t a l. (2 02 1, fi gs 4 -7 ) m id dl e sa nd bi an (l et ná f or m at io n) / ve se lá n ea r be ro un lo ca lit y ec co pt oc hi le cl av ig er a (b ey ri ch , 1 84 5) an om al ou s m or ph ol og y of th e se co nd a nd th ird p le ur al lo be o f p yg id iu m / su pp os ed ly la rg e ar th ro po d or n au til oi d ce ph al op od šn a jd r (1 98 0, p l. 1, fi g. 2 ), m id dl e sa nd bi an (l et ná f or m at io n) / d ra bo v ne ar be ro un ec co pt oc hi le cl av ig er a (b ey ri ch , 1 84 5) an om al ou s m or ph ol og y of th e se co nd a nd th ird p le ur al lo be s / su pp os ed ly la rg e ar th ro po d or n au til oi d ce ph al op od m o ra ve c (2 00 6, fi gs 1 -3 ) m id dl e sa nd bi an (l et ná f or m at io n) / ve se lá lo ca lit y d ea na sp is go ld fu ss i ( ba rr a n d e, 1 84 6) tr au m at ic d am ag e of th e rig ht a nt er ol at er al m ar gi n of c ep ha lic fr in ge , c al lu se d di st al e nd o f t he fi ft h an d si xt h rig ht th or ac ic p le ur a an d rig ht p os te ro la te ra l m ar gi n of p yg id iu m / un kn ow n šn a jd r (1 97 9a , p . 4 9, p l. 1, fi g. 1 ) m id dl e sa nd bi an (l et ná f or m at io n) / pr ah a – le tn á lo ca lit y d ea na sp is go ld fu ss i ( ba rr a n d e, 1 84 6) irr eg ul ar d is tr ib ut io n of fr in ge p its / un kn ow n šn a jd r (1 97 9a , p . 4 9, p l. 1, fi g. 2 ) m id dl e sa nd bi an (l et ná f or m at io n) / pr ah a – le tn á lo ca lit y d ea na sp is se nf te nb er gi (h aw le & c o rd a , 18 47 ) a s m ar ro lit hu s s en fte nb er gi ca llu se d ro un de d in de nt at io n at th e le ft p os te ro -la te ra l m ar gi n of p yg id iu m / un kn ow n šn a jd r (1 97 9a , p . 4 9, p l. 1, fi g. 4 ) la te s an db ia n to e ar ly k at ia n (v in ic e fo rm at io n) / pr ah a g eologia c roatica fatka et al.: healed injury in a nektobenthic trilobite: “octopus-like” predatory style in middle ordovician? 191 figured a pathological cephalon of the devonian lioharpes venulosus (hawle & corda, 1847). other pathological specimens were studied by prantl (1948, 1954). in the last sixty years, numerous trilobite exoskeletons showing healed traumatic inju­ ries and other kinds of anomalies have been documented from cambrian to devonian deposits (e.g., prantl & přibyl, 1954; šnajdr, 1978a, b, 1981, 1985, 1990a, b; budil et al., 2010; fatka et al., 2009, 2015; bicknell et al. 2021). here we describe an internal mould of the nileid trilobite parabarrandia bohemica (novák, 1884) housed in collections of the national museum prague. this partly enrolled specimen shows the below described palaeopathological anomaly on its py­ gidium. 2. geological setting ordovician skeletal fossils, including trilobites, have been known for more than 200 years in the barrandian area (e.g., schlotheim, 1823; barrande, 1846; for summary see bruthansová et al., 2007). the late middle­early upper ordovician šárka and do­ brotivá formations of the prague basin (fig. 1) are a classical source of diverse and well­preserved skeletal fauna (e.g., havlíček & vaněk, 1966), including abundant trilobites (budil et al., 2007). a rich association of disarticulated and ar­ ticulated trilobites, agnostids, echinoderms, brachiopods, hyo­ liths, organic­walled microfossils, and graptolites associated with remains of phyllocarid crustaceans, bivalves, cephalopods, ostra­ cods, and trace fossils have been thoroughly examined from these two formations for nearly two hundred years (chlupáč, 1970; kraft, 1972; budil et al., 2007; manda, 2008; polechová, 2013; lajblová & kraft, 2014; aubrechtová & turek, 2018; kraft et al., 2020). since the 19th century studi es, several tens of thousands articulated trilobite exoskeletons have been collected at several tens of outcrops of middle ordovician rocks (e.g., marek, 1961; budil et al., 2007; mergl et al., 2008). such extensive material occasionally includes anomalous specimens. 2.1. previously described cases of anomalous trilobites from the barrandian area, twenty anomalous trilobites showing healed traumatic injuries have been reported from late the mid­ dle to early late ordovician strata; data about these earlier re­ ports are summarized in table 1 and figures 1 and 2. 3. material and methods the studied specimen of parabarrandia is preserved as an inter­ nal mould in a siliceous nodule and is housed in the national mu­ seum, prague (inventory number nm l59869). the external mould is unknown. the specimen was collected by v. schüs from an unknown locality within the praha­šárka area in 1943. con­ sidering the lithology, it is likely to have been from the “u trian­ glu” site, which is within the higher levels of the šárka formation (see peršín & budil, 2009). the specimen was coated with ammonium chloride to enhance contrast and photographed with a digital canon eos 70 d camera. 4. description of the injured parabarrandia (fig. 3) the dorsoventrally flattened, slightly damaged and partly en­ rolled exoskeleton is 42 mm wide and 90 mm long. the smooth figure 2. stratigraphic ranges of injured trilobites and molluscs from the ordovician of the prague basin (barrandian area, czech republic). correlation modified from fatka et al. (2013), gutiérrez-marco et al. (2017) and colmenar et al. (2017). g eo lo gi a c ro at ic a geologia croatica 75/2192 surface of the internal mould has slender unbranched to irregu­ larly branched burrows assigned herein, following kraft et al. (2020), to the ichnogenera palaeophycus hall, 1847, arachnostega bertling, 1992 and pilichnus uchman, 1999. un­ branched cylindrical tunnels in the cephalon and the thoracic axis (reaching ~ 2 mm in diameter) are classified as palaeophycus isp. (pal in fig. 3a). narrow straight to slightly curved tunnels are common at the axial surface of the thorax and are observed in the axial and pleural pygidial surface; several intricate tunnels are noted in thoracic pleurae. such fine homogeneously distributed tunnels along the internal surface of the exoskeleton are classi­ fied as pilichnus isp. a wide pygidial doublure with fine terrace lines is exposed due to breaks of pleurae and lateral, posteriolateral and posterior pygidial margin. several minute pilichnus isp. are also seen in the doublure (pil in fig. 3b). fine, ramified burrows on the sur­ face of internal moulds with an oval cross-section are classified as arachnostega isp. (ar in fig. 3b). pilichnus has primarily been described from fine-grained soft substrates (uchman, 1999). in accordance with the limited acceptance of the substrate as an ichnotaxobase (bertling et al., 2006), we can also classify as pilichnus thin branched tunnels made in direct contact with the trilobite shell. pilichnus built in this way can be transferred to more complex systems corresponding to arachnostega. we sug­ gest that transitional forms between pilichnus isp. (= thin branch tunnels in contact with the shell) and arachnostega isp. (= open or almost closed networks in contact with the shell) can exist and are observed on the studied specimen. two prominent punctures are observed on the left anterior surface of the pygidial pleural field (arrows in figs. 3b, d). the larger puncture is elliptical with its longer axis oriented parallel with the pleural furrow (a in fig. 3d). the longer axis of this puncture reaches ~ 1.8 mm. the smaller puncture is rounded and measures 0.9 mm in diameter (b in fig. 3d). both punctures rep­ resent small craters surrounded by an elliptical swelling, which is ~ 9.5 mm wide and 4 mm long (dotted line in fig. 3d). remarks. morphologically comparable pit developed on up­ per and lower lamellae of the bilaminar cephalic fringe of the si­ lurian trilobite bohemoharpes ungula was described and figured by šnajdr (1978b, pl. 1, figs. 1-5; 1990, p. 62-63), who inter­ preted this anomaly as resulting from an activity of an endopara­ sitic organism. recently, this interpretation was also accepted by de baets et al. (2022, table 1). figure 3. parabarrandia bohemica (novák, 1884), šárka formation (middle ordovician, middle-late darriwilian), prague basin, praha-šárka locality. internal mould of the partly enrolled exoskeleton housed in the national museum prague under the inventory number nm l59869. a. view of the cephalon with four anterior thoracic segments, b. view of the pygidium with exposed doublure and the three posterior-most thoracic segments, c. reconstruction of the unrolled exoskeleton (adopted after fortey, 1985, fig. 5c), d. detail of the left side of the pygidium showing the position of the two punctures (a and b) and the surrounding swelling (marked by dotted line). ara arachnostega isp., pal palaeophycus isp., pil pilichnus isp. a, b, d – coated with ammonium chloride. g eologia c roatica fatka et al.: healed injury in a nektobenthic trilobite: “octopus-like” predatory style in middle ordovician? 193 5. discussion the ordovician record of injured skeletal invertebrates in the barrandian area includes gastropods, cephalopods, and trilobites. up to now, only two injured brachiopods are known (budil & fatka, unpublished observation). 5.1. injured gastropods failed predation and shell repair in ordovician bellerophontoide­ an gastropods were studied by horný (1996, 1997a, b, c) who reported examples of repaired shell breakage in sinuitops neglecta barrande in perner, 1903, bucanopsina calypso (perner, 1903), grandostoma bohemicum (perner, 1903), and lophospira infausta (barrande in perner, 1903) from the zahořany, bohdalec and králův dvůr formations (fig. 3). these specimens were collected from different districts of prague, for example spořilov, michle, hloubětín, štěrboholy, jinonice, and the králův dvůr locality (fig. 1c). horný (1997a, p. 168­169) distinguished three types of shell injuries in bel­ lerophontoidean gastropods: (1) scaloped u­shaped marginal breakages, (2) a scalloped crescentic marginal breakage, and (3) a deep local injury without a shell breakage and not representing the oichnus-trace fossil. the first type was interpreted as injuries caused by predatory molluscs, likely small cephalopods; the sec­ ond type was ascribed to non­biological causes or attacks by a small chelicerate arthropod or predatory echinoderms (e.g., ophi­ uroids). the third type of injury was explained as an injury made possibly by an ophiuroid or trilobite by horný (1997a, p. 167). 5.2. injured cephalopods aubrechtová (2015, p. 196, fig. 9c, j) described and figured two specimens of bactroceras sandbergeri barrande, 1867 with sub­lethally damaged shells from the middle­late darriwili an šárka formation from the osek and šárka localities. recently, aubrechtová & turek (2018, p. 408, figs. 5d, e, g) figured and briefly described trilacinoceras cf. discors (holm, 1891) with sublethal shell damage associated with anomalous growth (figs. 1c, 2) from the dobrotivá formation from the šárka locality. 5.3. injured trilobites owen (1985), babcock (1993, 2003, 2007), bicknell & paterson (2018), bicknell & smith (2021) and bick­ nell et al. (2022) published comprehensive reviews of trilobite abnormalities and discussed their possible causes. injuries ob­ served in diverse parts of the exoskeleton were ascribed to dam­ age due to predation or during ecdysis (babcock, 1993, p. 220). rudkin (1979, 1984), bicknell & paterson (2018, p. 5) and pates & bicknell (2019) considered sub­lethal in­ juries of trilobites during a moulting event showing signs of re­ generation including an over­thickened (calloused) cuticle along the scar. conversely, injuries without callouses are attributed to attacks on fully calcified individuals (jago & haines, 2002). in the barrandian area, injured trilobites have been classified to nine genera (table 1). the oldest recorded are the few trilobites from the šárka formation; similarly, there are rare specimens showing healed injuries in the overlying dobrotivá formation (table 1, fig. 2). the most abundant injured trilobite specimens are observed in the late sandbian letná formation, and the youngest malformed specimen was described from the late sand­ bian ­ early katian vinice formation (table 1, fig. 2). in following sections 5.3.1 – 5.3.3, the current knowledge on the supposed lifestyle of trilobite specimens is summarised. this summary reviews the potential predators. some trilobites were able to eliminate the predation pressure by cryptic behaviour (see fatka & budil, 2014), while other heavily skeletonised species or good swimmers effectively used passive defensive strategies. 5.3.1. benthic trilobites in the barrandian area, most ordovician trilobites with healed traumatic injury after failed predatory attacks have been classi­ fied as benthic and nektobenthic forms. placoparia zippei placoparia is one of the most common ordovician trilobites in the barrandian area (bruthansová & budil, 2003). be­ cause of the thick exoskeleton and the unattached (natant) hypos­ tome condition, this blind pliomerid genus has been usually con­ sidered as a benthic, partly buried, particle feeder by přibyl & vaněk (1976, p. 11), havlíček & vaněk (1990, p. 228; 1996, p. 227, 228, 236, 237), vokáč & grigar (2010, p. 162), bruthansová & budil (2003, p. 217), budil et al. (2007, p. 68), and rábano et al. (2010). fortey (1985, p. 228) clas­ sified this genus tentatively as an atheloptic trilobite. also, henry (1989, p. 148) included placoparia to taxa typical for the atheloptic assemblage of fortey & owens (1987). because of the wide palaeogeographical distribution of the darriwillian species placoparia cambriensis, owens & ser­ vais (2007, p. 282) expressed the opinion, that this species might have been epipelagic. however, they did not definitely exclude the possibility that placoparia belongs to atheloptic taxa. eoharpes and deanaspis deanaspis belongs to the most common trilobites in the letná formation (přibyl & vaněk, 1969). in comparison, remains of eoharpes are always rare in the šárka and dobrotivá forma­ tions (fatka & budil, 2014). species of both eoharpes and deanaspis have been interpreted as benthic filter feeders (e.g., havlíček & vaněk 1990, p. 230; 1996, p. 228, 236; mergl et al., 2008, p. 277). mikuláš & budil (2013) supposed that in deanaspis, the thorax was held above the water­sediment in­ terface, while the flat cephalic rim and long spines surrounded the filter-chamber beneath the cephalon and thorax, similarly as in cryptolithus tesselatus (see fortey & owens, 1999, p. 449, fig. 16). a comparable strategy is also supposed in the morpho­ logically similar harpetids (see fortey & owens, 1999, p. 448, fig. 14), including eoharpes. henry (1989, p. 148) listed eoharpes as a typical member of the atheloptic assemblage of fortey & owens (1987). a cluster of six articulated specimens of e. benignensis en­ tombed under a large asaphid pygidium described by fatka & budil (2014) documents the cryptic behaviour of these benthic trilobites. this gregarious cluster of small trilobites, incapable of a group defence, was explained by the ‘‘guide effect’’ reducing their risk of predation through attack abatement, both through dilution and avoidance effects (see childress & herrn­ kind, 1997). eccoptochile articulated exoskeletons of this large cheirurid trilobite are very rare, while disarticulated remains are quite abundant. havlíček & vaněk (1996, p. 236, 237), mergl et al. (2008, p. 277) and vokáč & grigar (2010, p. 162) classified eccoptochile as a benthic trilobite. g eo lo gi a c ro at ic a geologia croatica 75/2194 dalmanitina both disarticulated parts and articulated exoskeletons and dalmanitina are very common in the letná formation (fatka et al., 2021). přibyl & vaněk (1976, p. 9) classified dalmanitina as a good swimmer occasionally burrowing in the top layer of a shallow water bottom. asaphellus budil et al. (2007, p. 68) and mergl et al. (2008, p. 277) as­ signed this genus to large benthic predators. gibb et al. (2010), and more recently also neto de carvalho & baucon (2016) documented co­occurrence of the trace fossil genera rusophycus and cruziana and articulated exoskeletons of the asaphid trilobite asaphellus. such close association of the puta­ tive tracemarker and its trace documents a benthic life of these large and heavily skeletonised trilobites. 5.3.2. nektobenthic trilobites most pelagic trilobites were poorly streamlined (see fortey 1985), and it is supposed that they swam quite slowly. some larger trilobites like parabarrandia show a hydrofoil shape, with the head end prolonged into an elongate “nose,” comparable to extant sharks (fortey, 1985) and are hypothesized to have swum much faster. areiaspis budil et al. (2007, p. 68) and mergl et al. (2008, p. 277) clas­ sified rare specimens of this genus as deeper-water nektonic or benthic trilobites. the narrow axis and shape of its exoskeleton precluded good swimming ability. parabarrandia remains of this large nileid trilobite occur infrequently in the north-eastern part of the prague basin. fortey (1985, p. 223224; 2004, p. 450) assigned the large, nileid genus parabarrandia with its very streamlined exoskeleton and long anterior snout (or ‘nose’) to actively swimming pelagic inhabitants of the mesope­ lagic cyclopygid biofacies (fig. 4). in agreement with fortey (1985), henry (1989, p. 148) reported the occurrence of parabarrandia classified as a mesopelagic predator. in comparison, havlíček & vaněk (1990, p. 228; 1996, p. 228, 236) pre­ ferred a benthic life, while budil et al. (2007, p. 68), mergl et al. (2008, p. 277), peršín & budil (2009, p. 34), rabano et al. (2010, p. 420) and david & budil (2015, p. 4) classified it as a nektobenthic trilobite. 5.3.3. nektonic trilobites pricyclopyge binodosa binodosa this is the most common cyclopygid trilobite in the šárka for­ mation (marek, 1961; bruthansová, 2004, p. 304). fortey (1985, p. 223) as well as budil et al. (2007, p. 68) and mergl et al. (2008, fig. 277) classified the poorly streamlined cyclopygid pricyclopyge as a sluggish mesopelagic trilobite. 5.4. potential predators in the ordovician of the barrandian area, injured gastropods are ascribed to cephalopods, echinoderms and arthropods (horný, 1996, 1997a, b, c). injuries to cephalopods were likely interpreted to be made by other cephalopods (aubrechtová, 2015; au­ brechtová & turek, 2018). the malformed parabarrandia bohemica described and considered here also requires an expla­ figure 4. middle-late darriwilian šárka formation. sketch representing the distribution of major biofacies associated with the šárka formation. the shallowest part of the basin was inhabited by the poor orthid brachiopod association, further basinward, the placoparia association with rich trilobites, brachiopods and other skeletal fauna prevails; in the offshore slope settings it continuously passed into the poor atheloptic trilobite association which also included the poor benthic dendroid ‘gardens’. the water column was inhabited by sparse? planktonic graptolites and taxa of the poorly diverse caryocarids and cyclopygid biofacies. poorly oxygenated black shales in the central parts of the basin were dominated by the paterula association. modified after fatka & mergl (2009) with data published by lefebvre (2007) and fatka & vodička (in press). g eologia c roatica fatka et al.: healed injury in a nektobenthic trilobite: “octopus-like” predatory style in middle ordovician? 195 nation. alpert & moore (1975), whittington & briggs (1985), šnajdr (1980, 1981) and rábano & ar­ bizu (1999) proposed that sea anemones, anomalocarids and cephalopods caused the injuries of cambrian and ordovician tri­ lobites. bicknell et al. (2018, 2021 and 2022) suppose that tri­ lobites could damage other trilobites. brett & walker (2002, p. 94) suggested that priapulids, nautiloid cephalopods, phyllo­ carid crustaceans and other arthropods (e.g., eurypterids) were likely ordovician durophagous predators. the recently described specimen of dalmanitina with a malformed and regenerated eye is interpreted as an unsuccessful attack by a cephalopod or a large arthropod (fatka et al., 2021). from the morphology of the mal­ formed parabarrandia, combined with the large size of the taxon, we exclude predators including sea anemones, anomalocarids, echinoderms, and priapulids as the injury makers. consequently, cephalopods and arthropods are the potential culprits. 5.4.1. cephalopods recent cephalopods are commonly active carnivorous predators (fernández­álvarez et al., 2018). similarly, fossil cepha­ lopods are considered carnivorous (nixon, 1988 but see mi­ ronenko, 2020). large cephalopods were abundant in marine assemblages from the early ordovician (e.g., brett & walker, 2002; kröger, 2011), including the barrandian area (manda, 2008; aubrechtová, 2015 and aubrech­ tová & turek, 2018). 5.4.2. arthropods the length of the carapace of planktic phyllocarids does not ex­ ceed 50 mm in the ordovician (racheboeuf & crasquin, 2010). consequently, phyllocarids are excluded as a potential cul­ prit of the herein studied trilobite. presuming a benthonic mode of life for paleozoic marine chelicerates (for eurypterids see brady, 2001), sublethal predator−prey interactions between chelicerates and nektobenthic trilobites like parabarrandia might be possible. 5.5. ichnological aspect 5.5.1. feeding post-mortem after kraft et al. (2020) and other authors, producers of palaeophycus apparently preferred an easily accessible and nourish­ ing food that was easily consumed, e.g., their trace makers selec­ tively oriented on decaying soft tissues. the arachnostega and pilichnus traces are oriented in a manner suggesting systematic feeding. these trace makers spent more time in a carcass. the occurrence of palaeophycus, arachnostega and pilichnus in the internal mould of the parabarrandia attests to a post-mortem feeding activity on the trilobite carcass. also, the perfect articu­ lation of the trilobite exoskeleton suggests a carcass, not an exu­ vium (see vallon et al., 2015). 5.5.2. attack on living specimen of parabarrandia two prominent punctures penetrate the trilobite exoskeleton and are surrounded by swelling. the morphology in nm l59868 il­ lustrates, that this exoskeletal anomaly occurred in life of the parabarrandia, likely during the “paper­shelled” stage of hen­ ningsmoen (1975) or “soft-shelled” stage of speyer & brett (1985). the other possibility is in vivo attack by a culprit capable of boring. trace fossils representing morphologically recurring, lethal, sub­lethal (not completely successful) or “mistaken” (to empty shell) attacks are called praedichnia (see ekdale, 1985; val­ lon et al., 2016). most documentation of these trace fossils as­ cribe the record to holes drilled in mollusc and brachiopods. mikuláš et al. (2006) and jacobsen & bromley (2009) introduced ichnotaxonomical names for biting traces, subse­ quently attributed to praedichnia (compare pirrone et al., 2014 and vallon et al., 2016). confirmed living marine perpetrators drilling their prey are mainly gastropods and octopod cephalopods (vermeij, 2002, p. 385). most drill holes are interpreted to be caused by predatory gastropods such as naticids and muricids. bromley (1981) pro­ posed that the ichnofossils that are made by naticid drilling were oichnus paraboloides bromley, 1981 and muricids made oichnus simplex bromley, 1981. the holes in the pygidium of parabarrandia are morpho­ logically comparable to drill holes found in modern molluscs and crustaceans (e.g., arnold & arnold, 1969; boyle & knobloch, 1981; nixon & maconnachie, 1988; harper, 2002). the elliptical outline and dimensions of our drill holes are in accordance with the morphology of the ichno­ species oichnus ovalis bromley, 1993, an ichnofossil inter­ preted to be the result of boring by octopod cephalopods (see bromley, 1993; wisshak et al., 2015). further, the drilling of two or even three holes in one shell is a strategy known to be deployed in some species of recent octopods (nixon & ma­ connachie, 1988). nixon (1979, 1980) reported that in recent octopus vulgaris, the drilling activities are carried out by a salivary papilla lying just below the radula. the role of saliva produced by sali­ vary glands was later shown to be important for a successful at­ tack, as it contains a wide spectrum of paralysing and proteolytic substances (nixon, 1988, p. 709). some of them are responsible for the breakdown of the musculo­skeletal attachment mecha­ nism in crabs within 20 min of capture (nixon, 1984). similar breakdown of the musculo­skeletal attachment mechanism would probably mean the same for trilobites. the key ichnogenus oichnus bromley, 1981 and other morphologically similar ichnotaxa have been recently revised (wisshak et al., 2015). for the creation of our trace, drilling behaviour seems to be the most plausible because of the absence of sharp edges typical for biting, combined with the diminutive, protected space. in terms of systematic ichnology, the herein described struc­ tures from parabarrandia are attributable to the ichnospecies oichnus ovalis bromley, 1993. ancient, fossilised structures were interpreted as octopus borings, based on observations from studies of the recent octopods (bromley, 1993; nixon, 1979, 1980; nixon & maconnaiche 1988). based on these obser­ vations, we interpret the structures observed in the specimen of parabarrandia studied here as resulting from an “octopus­like” predatory attack. origination of the swelling on the internal mould. we sup­ pose that the trilobite was attacked during the “soft­shelled” stage. the thin exoskeleton was probably drilled (= “octopus­ like” predatory style). consequently, in the injured area, the soft tissue under the unbiomineralised exoskeleton overdeveloped. this swelling would have been recorded during exoskeletal hard­ ening with swelling expressed both on the external and internal surfaces of the exoskeleton. 6. conclusion (1) the exoskeletal anomaly seen at the left pygidial side of parabarrandia represents a partly healed injury after a failed preda­ tory attack during life. g eo lo gi a c ro at ic a geologia croatica 75/2196 (2) two scenarios explain this anomaly: a – the healed injury classified as the ichnospecies oichnus ovalis bromley, 1993 can be interpreted as an exoskeletal anomaly which originated after a failed “octopus­like” strategy of the predatory attack. this preferred interpretation reflects the nektobenthic lifestyle of parabarrandia and the nektonic life­ style of the suspected predator. b – the morphology and the extent of the swelling surround­ ing both punctures combined with the noticeable absence of any crack of the surrounding exoskeleton indicates the high flexibility of the cuticle during the attack. the attack resulted in two re­ stricted perforations (punctures) followed by plastic deformation of the exoskeleton copying the swelling. in such cases, the injury could result from attack of an unknown predatory arthropod. financial support: this research was supported by the czech science foundation (gacr) project no. 18­14575s and by cooperatio geol (of). competing interests: the authors declare that they have no conflict of interest. acknowledgement we acknowledge both reviewers lothar h. vallon (østsjæl­ lands museum, faxe, denmark) and russell d.c. bicknell (university of new england, armidale, new south wales, aus­ tralia) for their helpful review and the linguistic improvements that made on our text. m. valent (national museum, prague) is acknowledged for his help with photographing and tracing the origin of the specimen. this is a contribution to the igcp 653 “filling the gap between cambrian explosion and the gobe”. references alpert, s.p. & moore, j.n. (1975): lower cambrian trace fossil evidence for pre­ dation on trilobites.– lethaia, 8/3, 223–230. doi: 10.1111/j.1502­3931.1975. tb00926.x arnold, j.m. & arnold, k.o. (1969): some aspects of hole­boring predation by octopus vulgaris.– am. zoologist, 9/3, 991–996. doi: 10.1093/icb/9.3.991 aubrechtová, m. (2015): a revision of the ordovician cephalopod bactrites sandbergeri barrande: systematic position and palaeobiogeography of bactroceras.– geobios, 48/3, 193–211. doi: 10.1016/j.geobios.2015.03.002 aubrechtová, m. & turek v. (2018): lituitid cephalopods from the middle or­ dovician of bohemia and their paleobiogeographic affinities.– bull. geosci., 93/3, 401–417. doi: 10.314/bull.geosci.1707 babcock, l.e. (1993): trilobite malformations and the fossil record of behavioural asymmetry.– j. paleontol., 67/2, 217–229. doi: 10.1017/s0022336000032145 babcock, l.e. (2003): trilobites in paleozoic predator­prey systems, and their role in reorganization of early paleozoic ecosystems.– in: kelley, p., kowalews­ ki, m. & hansen, t.a. (eds.): predator–prey interactions in the fossil record. plenum publishers, new york, 55–92. doi: 10.1007/978-1-4615-0161-9_4 babcock, l.e. (2007): role of malformations in elucidating trilobite paleobiology: a historical synthesis.– in: mikulic, d.g., landing, e. & kluessendorf, j. (eds.): fabulous fossils–300 years of worldwide research on trilobites. new york state museum, new york, 507, 3–19. barrande, j. (1846): notice préliminaire sur le systême silurien et les trilobites de bohême.– c. l. hirschfeld, libraire, leipsic, 97 p. barrande, j. (1867): systême silurien du centre de la bohême. ser. 1.– praha and paris, 712 p. barrande, j. (1872): systême silurien du centre de la bohême. supplement i. tri­ lobites, crustace`s divers et poisson.– praha and paris, 647 p. bertling, m. (1992): arachnostega n. ichnog – burrowing traces in internal moulds of boring bivalves (late jurassic, northern germany).– paläontol. z., 66/1–2, 177–185. doi: 10.1007/bf02989487 bertling, m., braddy, s.j., bromley, r.g., demathieu, g.r., genise, j., mikuláš, r., nielsen, j.k., nielsen, k.s.s., rindsberg, a.k., schlirf, m. & uchman, a. (2006): names for trace fossils: a uniform ap­ proach.– lethaia, 39/3, 265–286. doi: 10.1080/00241160600787890 beyrich, e. (1845): über einige böhmische trilobiten.– g. reimer, berlin, 47 p. bicknell, r.d.c., holmes, j.d., pates, s., garcía­bellido, d.c. & paterson, j.r. (2022): cambrian carnage: trilobite predator­prey interactions in the emu bay shale of south australia.– palaeogeogr. palaeoclimatol. palaeo­ ecol., 591, 110877. doi: 10.1016/j.palaeo.2022.110877 bicknell, r.d.c., pates, s. & botton, m.l. (2018): abnormal xiphosurids, with possible application to cambrian trilobites.– palaeontol. electron., 21/2, 1–17. doi: 10.26879/866 bicknell, r.d.c., smith, p.m., bruthansová, j. & holland, b. (2021): malformed trilobites from the ordovician and devonian.– palz. doi:10.1007/ s12542­021­00572­9 bicknell, r.d.c. & pates, s. (2020): exploring abnormal cambrian­aged trilobites in the smithsonian collection.– peerj, 8, e8453. doi: 10.7717/peerj.8453 bicknell, r.d.c. & paterson, j.r. (2018): reappraising the early evidence of durophagy and drilling predation in the fossil record: implications for escalation and the cambrian explosion.– biol. rev., 93/2, 754–784. doi: 10.1111/brv.12365 bicknell, r.d.c. & smith, p.m. (2021): teratological trilobites from the silurian (wenlock and ludlow) of australia.– sci. nat., 108, 58. doi: 10.1007/s00114­021­ 01766­6 boeck, c.p.b. (1827): notitser til laeren om trilobiterne.– magazin for naturviden­ skaberne, 1, 11–44. boyle, p.r. & knobloch, d. (1981): hole boring of crustacean prey by the octo­ pus eledone cirrhosa (mollusca, cephalopoda).– j. zool., 193, 1–10. doi: 10.1111/ j.1469­7998.1981.tb01486.x brady, s.j. (2001): eurypterid palaeoecology: palaeobiological, ichnological and com­ parative evidence for a “mass­moult­mate” hypothesis.– palaeogeogr. palaeocli­ matol. palaeoecol., 172, 115–132. doi: 10.1016/s0031­0182(01)00274­7 brett, c.e. & walker, s.e. (2002): predators and predation in paleozoic marine environments.– in: kowalewski, m. & kelley, p.h. (eds.): the fossil re­ cord of predation. spec. pap. in paleontol., 8, 93–118. bromley, r.g. (1981): concepts in ichnology illustrated by small round holes in shells.– acta geol. hisp., 16, 55–64. bromley, r.g. (1993): predation habits of octopus past and present and a new ichno­ species, oichnus ovalis.– bull. geol. soc. den., 40/1–2, 167–173. bruthansová, j. (2004): exuviation of selected bohemian ordovician trilobites.– spec. pap. palaeont., 70, 293–308. bruthansová, j. & budil, p. (2003): exuviation of the genus placoparia hawle et corda, 1847 (trilobita, czech republic, prague basin, ordovician).– in: al­ banesi, g.l., beresi, m.s. & peralta, s.h. (eds.): ordovician from the andes. insugeo, ser. correlación geol., 17, 267–269. bruthansová, j., fatka, o., budil, p. & král, j. (2007): 200 years of trilobite research in the czech republic.– in: mikulic, d.g., landing, e. & klues­ sendorf, j. (eds.): fabulous fossils–300 years of worldwide research on tri­ lobites. new york state museum, new york, 507, 51–80. budil, p., kraft, p., kraft, j. & fatka, o. (2007): faunal associations of the šárka formation (middle ordovician, darriwilian, prague basin, czech repub­ lic).– acta palaeontol. sinica, 46/suppl., 64–70. budil, p., fatka, o., rak, š. & zwanzig, m. (2010): two unique middle ordo­ vician trilobites from the prague basin, czech republic.– j. national mus., nat. hist., 179/8, 95–104. chlupáč, i. (1970): phyllocarid crustaceans of the bohemian ordovician.– sbor. ge­ ol. věd, paleontol., 12, 41–75. childress, m.j. & herrnkind, w.f. (1997): den sharing by juvenile caribbean spiny lobsters (panulirus argus) in nursery habitat: cooperation or coincidence?– mar. freshwater res., 48/8, 751–758. doi: 10.1071/mf97158 colmenar, j., pereira, s., pires, m., da silva, c.m., sá, a.a. & young, t.p. (2017): a kralodvorian (upper katian, upper ordovician) benthic association from the ferradosa formation (central portugal) and its significance for the redefinition and subdivision of the kralodvorian stage.– bull. geosci., 92/4, 443–464. doi: 10.3140/bull.geosci.1643 david, m. & budil, p. (2015): complementary description of the middle ordovician trilobite associations at praha­vokovice.– folia mus. rer. natur. bohem, occident., geol. paleobiol., 49/1–2, 1–7. doi: 10.1515/fbgp­2015­0001 de baets, k., budil, p., fatka, o. & geyer, g. (2022): trilobites as hosts for parasites: from paleopathologies to ethiologies.– in: de baets, k. & huntley, j.w. (eds.): the evolution and fossil record of parasitism. topics in geobiology, 50, 173–201. doi: 10.1007/978-3-030-52233-9_6 ekdale, a.a. (1985): paleoecology of the marine endobenthos.– palaeogeogr. palae­ oclimatol. palaeoecol., 50/1, 63–81. doi: 10.1016/s0031­0182(85)80006­7 fatka, o. & budil, p. (2014): sheltered gregarious behavior of middle ordovician harpetid trilobites.– palaios, 29/9, 495–500. doi: 10.2110/palo.2013.031 fatka, o., budil, p. & grigar, l. (2015): a unique case of healed injury in a cam­ brian trilobite.– ann. paléontol., 101/4, 295–299. doi: 10.1016/j.annpal.2015.10.001 fatka. o., lerosey-aubril, r., budil, p. & rak, š. (2013): fossilised guts in trilobites from the upper ordovician letná formation (prague basin, czech re­ public).– bull. geosci., 88/1, 95–104. doi: 10.3140/bull.geosci.1329. fatka, o., budil, p. & zicha, o. (2021): exoskeletal and eye repair in dalmanitina socialis (trilobita): an example of blastemal regeneration in the ordovician? int. j. paleopathol., 34, 113–121. doi: 10.1016/j.ijpp.2021.05.011 g eologia c roatica fatka et al.: healed injury in a nektobenthic trilobite: “octopus-like” predatory style in middle ordovician? 197 fatka, o. & mergl, m. (2009): the “microcontinent” perunica: status and story 15years after conception. in: bassett, m.g. (ed.): early palaeozoic peri­gond­ wanan terranes: new insights from tectonics and biogeography. geol. soc. lon­ don, spec. publ., 325, 65–102. doi:10.1144/sp325.4 fatka, o., szabad, m. & budil, p. (2009): malformed agnostids from the middle cambrian jince formation of the příbram–jince basin, czech republic.– bull. geosci., 84/1, 121–126. doi: 10.3140/bull.geosci.1107 fatka, o. & vodička, j. (in press): putative ordovician green alga krejciella rein­ terpreted as a tube of hemichordate.– palaeontol. electron. fernández­álvarez, f.á., machordom, a., garcía­jiménez, r., sali­ nas-zavala, c.a. & villanueva, r. (2018): predatory flying squids are detritivores during their early planktonic life.– sci. rep., 8, 3440. doi: 10.1038/ s41598­018­21501­y fortey, r.a. (1985): pelagic trilobites as an example of deducing the life habits of extinct arthropods.– t. roy. soc. edin­earth., 76/2–3, 219–230. doi: 10.1017/ s0263593300010452 fortey, r.a. (2004): the lifestyles of the trilobites.– am. sci., 92/5, 446–453. doi: 10.1511/2004.5.446 fortey, r.a. & owens, r.m. (1987): the arenig series in south wales.– bull. brit. mus. (nat. hist.) geol. ser., 41/3, 69–307. fortey, r.a. & owens, r.m. (1999): feeding habits in trilobites.– palaeontology, 42/3, 429–465. doi: 10.1111/1475­4983.00080 gibb, s., chatterton, b.d.e. & gingras, m.k. (2010): rusophycus carleyi (james, 1885), trace fossils from the lower ordovician of southern morocco, and the trilobites that made them.– ichnos, 17/4, 271–283. doi: 10.1080/10420940. 2010.535452 gutiérrez­marco, j.c., sá, a.a., garcía­bellido, d.c. & rábano, i. (2017): the bohemo­iberian regional chronostratigraphical scale for the ordovi­ cian system and palaeontological correlations within south gondwana.– lethaia, 50/2, 258–295. doi: 10.1111/let.12197 hall, j. (1847): paleontology of new york, vol. 1. van benthuysen, albany, 338 p. harper, e.m. (2002): plio­pleistocene octopod drilling behavior in scallops from flori­ da.– palaios, 17/3, 292–295. doi: 10.1669/0883­1351(2002)017<0292:ppodbi>2. 0.co;2 havlíček, v. & vaněk, j. (1966): the biostratigraphy of the ordovician of bohe­ mia.– sbor. geol. věd, paleontol., 8, 7–69. havlíček, v. & vaněk, j. (1990): ordovician invertebrate communities in black– shale lithofacies (prague basin, czechoslovakia).– věst. ústřed. úst. geol., 65/4, 223–236. havlíček, v. & vaněk, j. (1996): dobrotivian/berounian boundary interval in the prague basin with a special emphasis on the deepest part of the trough (ordovi­ cian, czech republic).– věst. ústřed. úst. geol., 71/3, 225–243. hawle, i. & corda, a.j.c. (1847): prodrom einer monographie der böhmischen trilobiten.– abh. k. böhm. ges. wiss., 5, 117–292. henningsmoen, g. (1975): moulting in trilobites.– fossils and strata, 4, 179–200. henry, j.-l. (1989): paléoenvironnements et dynamique de faunes de trilobites dans l’ordovicien (llanvirn supérieur-caradoc basal) du massif armoricain (france).– palaeogeogr. palaeoclimatol. palaeoecol., 73/1–2, 139–153. doi: 10.1016/0031­ 0182(89)90049­7 holm, g. (1891): om mynningen lituites.– geol. fören. stock. för., 13, 736–776. doi: 10.1080/11035899109445850 horný, r.j. (1996): grandostoma: an additional bellerophontiform mollusc with cir­ cumbilical retractor muscle attachment areas (gastropoda, bellerophontoidea).– j. czech geol. soc., 41/3­4, 223–228. horný, r.j. (1997a): shell breakage and repair in explanate bellerophontoidean gas­ tropods from the middle ordovician of bohemia.– věst. čes. geol. úst., 72/2, 157–168. horný, r.j. (1997b): shell breakage and repair in sinuitops neglecta (mollusca, ter­ gomya) from the middle ordovician of bohemia.– čas. nár. muz., ř. přírodověd., 166/1­4, 137–142. horný, r.j. (1997c): ordovician tergomya and gastropoda of the anti­atlas (mo­ rocco).– acta musei nat. pragae, series b, nat. hist., 53/3­4, 37–78. jacobsen, a.r. & bromley, r.g. (2009): new ichnotaxa based on tooth impres­ sions on dinosaur and whale bones.– geol. q., 53/4, 373–382. jago, j.b. & haines, p.w. (2002): repairs to an injured early middle cambrian tri­ lobite, elkedra area, northern territory.– alcheringa, 26/1, 19–21. doi: 10.1080/ 03115510208619241 kraft, j. (1972): type specimens of fossils in the west-bohemian museum in plzeň and in the regional museum of dr. b. horák in rokycany. part i – trilobita.– fo­ lia mus. rer. natur. bohem, occident., geol., 1, 1–11. kraft, p., bruthansová, j. & mikuláš, r. (2020): feeding traces related to shells from the prague basin, czech republic (tremadocian to early darriwilian, ordovician).– palaeogeogr. palaeoclimatol. palaeoecol., 537, 109399. doi: 10.1016/j.palaeo.2019.109399 kröger, b. (2011): size matters – analysis of shell repair scars in endocerid cepha­ lopods.– foss. rec., 14/2, 109–118. doi: 10.1002/mmng.201100001 lajblová, k. & kraft, p. (2014): the earliest ostracods from the ordovician of the prague basin, czech republic.– acta geol. pol., 64/4, 367–392. doi: 10.2478/agp­ 2014­0021 lefebvre, b. (2007): early palaeozoic palaeobiogeography and palaeoecology of stylophoran echinoderms.– palaeogeogr. palaeoclimatol. palaeoecol., 245/1, 156–199. doi: 10.1016/j.palaeo.2006.02.021 manda, š. (2008): trocholites conrad, 1838 (nautiloidea, tarphycerida) in the mid­ dle ordovician of the prague basin and its palaeobiogeographical significance.– bull. geosci., 83/3, 327–334. doi: 10.3140/bull.geosci.2008.03.327 marek, l. (1961): the trilobite family cyclopygidae raymond in the ordovician of bohemia.– rozpr. ústřed. úst. geol., 28, 1–84. mergl, m., fatka, o. & budil, p. (2008): lower and middle ordovician trilobite associations of perunica: from shoreface endemicity to offshore uniformity (prague basin, czech republic).– in: rábano, i., gozalo, r. & garcía­bellido, d. (eds.): advances in trilobite research. cuadernos del museo geominero, 9, 275–282. mikuláš, r. & budil, p. (2013): the ichnofossil rusophycus cf. cryptolithi osgood, 1970 as a trace of the trilobite deanaspis goldfussi (barrande, 1846) from the let­ ná formation (upper ordovician, barrandian area, czech republic).– geosci. res. rep. 2012, 192–194. mikuláš, r., kadlecová, e., fejfar, o. & dvořák, z. (2006): three new ichnogenera of biting and gnawing traces on reptilian and mammalian bones: a case study from the miocene of the czech republic.– ichnos, 13/3, 113–127. doi: 10.1080/10420940600850729 mironenko, a.a. (2020): endocerids: suspension feeding nautiloids?– hist. biol., 32/2, 281–289. doi: 10.1080/08912963.2018.1491565 moravec, j.k. (2006): a pathologic pygidium of the eccoptochile clavigera (beyrich, 1845) (trilobita) from the letná formation of the bohemian ordovician in the prague basin (barrandian).– geosci. res. rep., 2005, 91. [in czech with english summary] neto de carvalho, c. & baucon, a. (2016): giant trilobite burrows and their paleobiological significance (lower-to-middle ordovician from penha garcia, portugal).– comun. geol., 103, 71–82. nixon, m. (1979): has octopus vulgaris a second radula?– j. zool., 187/3, 291–296. doi: 10.1111/j.1469­7998.1979.tb03370.x nixon, m. (1980): the salivary papilla of octopus as an accessory radula for drilling shells.– j. zool., 190/1, 53–57. doi: 10.1111/j.1469­7998.1980.tb01422.x nixon, m. (1984): is there external digestion by octopus?– j. zool., 202/3, 441–447. doi: 10.1111/j.1469­7998.1984.tb05094.x nixon, m. (1988): the feeding mechanisms and diets of cephalopods ­ living and fos­ sil.– in: wiedmann, j. & kullmann, j. (eds.): cephalopods present and past. 2nd international cephalopod symposium, e. schweizerbart’sche verlags­ buchhandlung, stuttgart, 642–652. nixon, m. & maconnachie, e. (1988): drilling by octopus vulgaris (mollusca: cephalopoda) in the mediterranean.– j. zool., 216/4, 687–716. doi: 10.1111/ j.1469­7998.1988.tb02466.x novák, o.p. (1884): studien an hypostomen böhmischer trilobiten nr. ii.– sitzber. k. böhm. ges. wiss., 212–229. owen, a.w. (1985): trilobite abnormalities.– t. roy. soc. edin­earth, 76/2–3, 255–272. doi: 10.1017/s0263593300010488 owens, r.m. & servais, t. (2007): the ordovician of the condroz inlier, belgium: trilobites from the southeastern margin of avalonia.– palaeogeogr. palaeoclima­ tol. palaeoecol., 245/1­2, 272–294. doi: 10.1016/j.palaeo.2006.02.025 pates, s. & bicknell, r.d.c. (2019): elongated thoracic spines as potential preda­ tory deterrents in olenelline trilobites from the lower cambrian of nevada. palaeo­ geogr. palaeoclimatol. palaeoecol., 516, 295–306. doi: 10.1016/j.palaeo.2018.12.013 perner, j. (1903): systême silurien du centre de la bohême. gastéropodes 4/1.– pra­ ha and paris, 164 p. perner, j. (1918): trilobites of d-d1γ from the surrounding of prague.– palaeont. bo­ hem., 9, 1–55. [in czech] peršín, j. & budil, p. (2009): new observations on šárka and dobrotivá formation (ordovician, darriwilian stage) in northwestern and northern surroundings of prague.– český kras, 35, 25–35. [in czech with english summary] pirrone, c.a., buatois, l. & bromley, r.g. (2014): ichnotaxobases for bioero­ sion trace fossils in bones. j. paleont., 88/1, 195–203. doi: 10.1666/11­058 polechová, m. (2013): bivalves from the middle ordovician šárka formation (prague basin, czech republic).– bull. geosci., 88/2, 427–461. doi: 10.3140/bull. geosci.1426 prantl, f. (1948): malformations in the genus crotalocephalus salter.– rozpr. čes. akad. věd um., tř. ii, 57/1, 1–14. [in czech] prantl, f. (1954): teratology of the species harpes venulosus hawle a corda.– čas. nár. muz., ř. přírodověd., 123/1, 121. [in czech] prantl, f. & přibyl, a. (1954): on the bohemian representatives of the family har­ petidae (hawle & corda).– rozpr. ústřed. úst. geol., 18, 1–170 [in czech with russian and english summary] přibyl, a. & vaněk, j. (1969): trilobites of the family trinucleidae hawle et corda, 1847 from the ordovician of bohemia.– sbor. geol. věd, paleontol., 11, 85–137. g eo lo gi a c ro at ic a geologia croatica 75/2198 přibyl, a. & vaněk, j. (1976): palaeoecology of berounian trilobites from the bar­ randian area (bohemia, czechoslovakia).– rozpr. českoslov. akad. věd, ř. mate­ mat. přírod. věd, 86/5, 1–40. rábano, i. & arbizu, m. (1999): exoskeletal abnormalities in trilobites from spain.– rev. esp. paleont. vol. extr homenaje al prof. j. truylos, 109–113. [in spanish] rábano, i., sá, a.a., guttiérez­marco, j.c. & garcía­bellido, d.c. (2010): two more bohemian trilobites from the ordovician of portugal and mo­ rocco.– bull. geosci., 85/3, 415–424. doi: 10.3140/bull.geosci.1173 racheboeuf, p.r. & crasquin, s. (2010): the ordovician caryocaridid phylloca­ rids (crustacea): diversity and evolutionary tendencies.– n. jb. geol. paläont., abh, 257(2), 237–248. doi: 10.1127/0077­7749/2010/0075 rudkin, d.m. (1979): healed injuries in ogygopsis klotzi (trilobita) from the middle cambrian of british columbia.– roy. ontario museum, life sci. occasional pap., 32, 1–8. rudkin, d.m. (1984): exoskeletal abnormalities in four trilobites.– can. j. earth sci., 22, 479–483. salter, j.w. in murchison r.i. (1859): siluria. the history of the oldest known rocks containing organic remains, with a brief description of the distribution of gold over the earth. 3rd edn.– london, 592 p. schlotheim, e.f. (1823): nachträge zur petrefactenkunde, zweyte abtheilung.– becker, gotha, 114 p. šnajdr, m. (1956): the trilobites from the drabov and letná beds of the ordovician of bohemia.– sbor. ústřed. úst. geol., odd. paleontol., 22, 477–533. [in czech with english summary] šnajdr, m. (1978a): anomalous carapaces of bohemian paradoxid trilobites. sbor. geol. věd, paleontol., 20, 7–31. šnajdr, m. (1978b): pathological neoplasms in the fringe of bohemoharpes (trilo­ bita). věst. ústř. úst. geol., 53/4, 301–305. šnajdr, m. (1979a): two trinucleid trilobites with repair of traumatic injury.– věst. ústřed. úst. geol., 54/1, 49–50. šnajdr, m. (1979b): note on the regenerative ability of injured trilobites.– věst. ústřed. úst. geol., 54/3, 171–173. šnajdr, m. (1980): pathological exoskeletons of two ordovician trilobites (czecho­ slovakia).– čas. nár. muz., ř. přírodověd., 148/3-4, 173–176. [in czech with eng­ lish summary] šnajdr, m. (1981): bohemian proetidae with malformed exoskeletons (trilobita).– sbor. geol. věd, paleontol., 24, 37–61. šnajdr, m. (1985): anomalous exoskeletons of bohemian encrinurine trilobites.– věst. ústřed. úst. geol., 60/5, 303–306. šnajdr, m. (1990a): bohemian trilobites.– czech geological survey, praha, 265 p. šnajdr, m. (1990b): five extremely malformed scutelluid pygidia (styginidae, trilo­ bita).– věst. ústřed. úst. geol., 65/2, 115–118. speyer, s.e. & brett, c.e. (1985): clustered trilobite assemblages in the middle devonian hamilton group.– lethaia, 18/2, 85–103. doi: 10.1111/j.1502­3931.1985. tb00688.x uchman, a. (1999): ichnology of the rhenodanubian flysch (lower cretaceous­eo­ cene) in austria and germany.– beringeria, 25, 67–173. vermeij, g.j. (2002): evolution in the consumer age: predators and the history of life.– in: kowalewski, m. & kelley, p.h. (eds.), the fossil record of predation. paleontol. soc., spec. pap., 8, 375–394. doi: 10.1017/s1089332600001169 vallon, l.h., rindsberg, a.k. & bromley, r.g. (2016): an updated classifi­ cation of animal behaviour preserved in substrates.– geodin. acta, 28/1–2, 5–20. doi:10.1080/09853111.2015.1065306 vallon, l.h., schweigert, g., bromley, r.g., röper, m. & ebert, m. (2015): ecdysichnia – a new ethological category for trace fossils produced by moulting.– ann. soc. geol. pol., 85, 433–444. doi:10.14241/asgp.2015.027 vokáč, v. (1996): on some abnormities of trilobite exoskeletons from central bohe­ mian palaeozoikum).– palaeontol. bohem., 2, 20–22. [in czech with english sum­ mary] vokáč, v. & grigar, l. (2010): occurence of the fossiliferous ordovician dobro­ tivá formation (upper darriwilian to lower sandbian?) at tymákov (western part of the prague basin, barrandian area, czech republic).– erica, 17, 159–163, [in czech with english summary] whittington, h.b. & briggs, d.e.g. (1985): the largest cambrian animal, anomalocaris, burgess shale, british columbia.– philos. t. r. soc. b, 309, 569–609. doi: 10.1098/rstb.1985.0096 wisshak, m., kroh, a., bertling, m., knaust, d., nielsen, j.k., jagt, j.w.m., neumann, c. & nielsen, k.s.s. (2015): in defence of an iconic ich­ nogenus – oichnus bromley, 1981.– ann. soc. geol. pol., 85/3, 445–451. 2019 | 72 / special issue | 111–126 | 19 figs. | 8 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1 introduction ore grade estimation is an important aspect of mine value evaluation. the inverse distance weighted (idw) and ordinary kriging (ok) are the most commonly used ore grade interpolation methods (novak zelenika et al., 2017). the idw method is a widely used simple and convenient ore grade estimation method. the smoothness of idw interpolation results is directly affected by the number of samples included in the estimation. the ok method is unbiased and has evolved into a series of estimation methods including linear and nonlinear processes. the ok method is one of the most important kriging methods, giving results with high smoothness (wang et al., 2016; kumari & singh, 2018). in addition, ok uses a variogram to estimate the weight of the samples, but the variogram can only use the information between the two points. multi-point geostatistics uses a training image instead of a variogram, which considers information from multiple samples, which is advantageous compared to the ok method. the single normal equation simulation (snesim) is the most classic multi-point geostatistics (mpg) method. scholars developed a series of improvements based on the snesim method (zhang et al., 2015; hansen & le, 2016). the simulation of patterns (simpat) method compares the similarity between data events and data patterns in the training image and replaces data events with the most similar pattern (burc arpat & caers, 2007; yang, 2014). the simpat method used the similarity calculation to compare the similarity between the data events and the data patterns in the training image and replaces the data events with the most similar pattern. the simpat method weakened the data stability requirement compared to the snesim method, which had some advantages; however, some errors in the data pattern selection and target continuity still exist. for example, sampling results from edge probabilities increase the estimation uncertainty by not considering data fully. a multi-point geostatistical simulation based on the reservoir skeleton (smps) used the shape, type, and scale of the target body multi-point geostatistics for ore grade estimation yu-chen song1, zhan-ning liu1, hai-dong meng1 and xiao-yan yu1 1 inner mongolia university of science and technology, institute of mining engineering, baotou 014010, p.r. china; (songyuchen@imust.edu.cn; 494570031@qq.com; haidongm@imust.edu.cn; 421351047@qq.com) doi: 10.4154/gc.2019.23 abstract a multi-point geostatistical method for ore grade estimation is introduced in order to fully utilize existing sampling information. a block model is used to construct a new three-dimensional training image instead of a variogram. data events and pattern matching is improved, and the directionality of the data template is considered in the matching. the inverse distance weighted method is used to make up for the lack of multi-point geostatistics. the research improves the reliability of multi-point geostatistical estimation. optimal estimation results for li2o and ta2o5 come from the inverse distance weighted, ordinary kriging, and multi-point geostatistical methods. multi-point geostatistical estimation results are compared with those of the inverse distance weighted and ordinary kriging methods. deviation, trend, and variogram analyses are used to assess the effect of multipoint geostatistical estimation. this study shows that reducing the samples participating in the estimation can reduce the maximum and minimum deviation of the estimated grade to a certain extent. the grade distribution pattern is the primary factor affecting minimum and maximum deviation. this study proves the reliability and accuracy of the multipoint geostatistical method for ore grade estimation. contained in the skeleton model to constrain and guide the multipoint prediction results of the target simulation (yin et al., 2008a, 2008b) and was mainly used for river phase mode simulation. since the skeletal model for the target body was predicted before the simulation, simulation uncertainty can be reduced, and the continuity of the target body can be improved. the filtersim method was used to remedy the long processing time of the snesim method (zhang et al., 2006). the filtersim method determined the appropriate classification and dimensionality reduction of data events in the image while maintaining estimation accuracy. the dimensionality reduction process was implemented using a mode filter combined with the filtersim method (yu et al., 2016). mode filters selected for a specific line ar combination of mode cell values include directional average, gradient, and curvature. the improved method was primarily used for reservoir phase pattern simulation (wu & fu, 2016; straubhaar et al., 2016). simulations were mostly pattern simulations (vries et al., 2009; huysmans et al., 2014), comprehensive simulations (lou et al., 2015; gardet et al., 2016), parameter optimization (gao et al. 2016), and computational efficiency research (zuo et al., 2016; abdollahifard & nasir, 2017). there are few studies on the patterns of continuous variables, and even fewer have been conducted on the calculation of resource reserves using the mpg method. here, the snesim method is adapted and used for ore grade estimation. multi-point geostatistics are compared with statistics from the ok and the idw methods to confirm the validity of the results. deviation analysis, trend analysis, and variogram analysis are used to examine the estimation characteristics. 2 research methods this section introduces the idw, ok, and mpg methods as well as an improved mpg method, which overcomes the uncertainty in matching data templates to data events by incorporating the idw method. article history: manuscript received march 06, 2019 revised manuscript accepted july 19, 2019 available online december 20, 2019 keywords: training image, grade, multi-point geostatistics, variogram g eo lo gi a c ro at ic a geologia croatica 72 / special issue112 2.1. inverse distance weighted (idw) estimation the inverse distance weighted (idw) method is a geometric space interpolation method (spatial statistics) and is one of the most commonly used spatial interpolation methods. it uses the inverse relationship of the distance index powers of known neighbour values to estimate grid point values and can be expressed by the equation (li et al., 2008): 1 1 1 1 = = = ∑ ∑ n ip ii n p ii z d z d (1) where z is the estimation value for the point to be estimated. zi is the i-th (i = 1, 2, ..., n) sample participating in the estimation. di is the distance between the point to be estimated and the sample. p is the power of the distance. the value of p significantly affects the interpolation result, and its selection criterion is the minimum average absolute error. 2.2. kriging estimation it is important to understand the theoretical explanation of the ordinary kriging method, its experimental variogram, and theoretical variogram. 2.2.1. variogram the variogram is an important tool in the ok method and can be used alone or as the basis for the kriging method to study the spatial variability of ore grades. the experimental variogram can be written as: [ ]21( , ) ( ) ( ) 2 γ = − +x h e z x z x h (2) where γ(x, h) is the variogram value. h is the lag distance or distance between samples. z(x) and z(x+h) are the observed values of the regionalized variable z at positions x and x+h, respectively. the experimental variogram provides the spatial variation of the sample grade. however, an experimental variogram cannot be directly used in kriging estimation (geiger et al., 2016). it is necessary to fit the experimental variogram and obtain a theo retical curve after fitting, which is the theoretical variogram. the theoretical variogram can be used in kriging estimation, and theoretical variograms used in this study are based on spherical, power function, and fractal models. 1. spherical model 3 0 3 0 0 0 3 1( ) 0 2 2 c γ =   = + ⋅ − ⋅ < ≤       + > h h hh c c a h a a c h a (3) whereγ(h) is the value of experimental variogram. c0 is the nugget value. h is the lag distance. c is the arch height. c0+c is the sill value. a is the range. 2. power function model ( ) , 0 2θγ θ= < <h ah (4) where θ is a power exponent. a is a constant. other parameters are the same as eq. (3). 3. fractal model the variogram of the fractal brownian motion is expressed as: 2( )γ = h hh v h (5) where: vh is a constant. h is the lag distance. h is the discontinuity index (hurst index). 2.2.2. ordinary kriging (ok) estimation if x be any point to be evaluated in the study area, then the ore grade at point x can be expressed as: * 1 ( ) ( )λ = =∑ n v i i i z x z x (6) where z* v(x) is an estimation value of the point to be estimated. xi is the i-th most recent sample around the point to be estimated. z(xi) is the grade of the i-th most recent sample within the range to be estimated. λi is the weight. in eq. (6), the estimation depends on the weight coefficient λi, while solving for the optimal λi value becomes essential to estimation. the best estimation is considered to be unbiased and has the least variance (optimal condition) in the ok. if the e[z(x)]=m of the ore grade z(x) is known, the calculation is called a simple kriging estimation. if e[z(x)] of z(xi) is unknown, the calculation is called ordinary kriging (ok). 2.3. multi-point geostatistical estimation 2.3.1. principle of the snesim the classic snesim method takes multi-point geostatistics from theory to practicality, which is of great significance (strebelle, 2017). the snesim uses data events to estimate the local probability of the point to be estimated. for two-point statistics, the probability that the variable type is sk state is written as: [ ]( , ) ( ; ) ( ; )φ = × +h k e i u k i u h k (7) where φ(h, k) represents the probability that variable types are sk states at locations u and u+h. sk represents the possible k states of the attribute s. k=1,…, k. h is the distance between two points. i(u; k) represents the probability when the state at position u is sk. i(u+h; k) represents the probability when the state at position u+h is sk. the sample tn is determined by n vectors (hα, α=1, ..., n). the probability that n data points (u+h1, ..., u+hn) are simultaneously sk can be expressed by the following equation: 1 ( , ) ( ; )α α=   φ = +     ∏ n h k e i u h k (8) where φ(h, k) represents the probability that multiple point attributes are sk. (u+h1, ..., u+hn) take the values of the probability of sk1, ...,skn respectively, which is written as: 1 1 1 ( , , , , , ) ( ; )α α α=   φ = +     ∏  n n nh h k k e i u h k (9) where φ(h1,…,hn, k1,…,kn) is the probability that multiple points have different attribute states. by analyzing the definition of a data event, the probability of the data event dn is the probability of the above probability event, which is written as: 1 1 ( ) ( , , , , , )φ =  n n n n c d h h k k n (10) g eologia c roatica song et al.: multi-point geostatistics for ore grade estimation 113 where c(dn) is the number of times the data event dn appears in the training image. nn is the number of data events contained in the training image. assuming that the data event constitutes the indicator variable, d is written as: 1 ( ) , 1, , 0 α α α= ∀ = =   ks u s n d other (11) where s(uα)=skα, which indicates a case where the attribute s is the state k at location uα. the value of the estimation center point ak can be written as: 1 ( ) 0 = =   k k s u s a other (12) where ak is an indicator variable associated with the occurrence of state sk at location u. using the simple kriging method, the probability that any point will have a given attribute type is written as: [ ]( )1| 1 1λ= = = + −      k kprob a d e a e d (13) where ak=1 is an indicator value corresponding to datum value sk at location u. d=1 is the observed data event. e[ak] is the probability of the (unknown) state at location u to be sk. e[d] is the probability of the conditioning data event occurring. λ is the single weight. the weight λ can be determined by: [ ]var ,λ =   kd cov a d , and [ ], = −          k k kcov a d e a d e a e d , [ ] [ ] [ ]( )var 1= −d e d e d . thus there is: [ ] [ ] [ ]( )1 λ −      = − k ke a d e a e d e d e d (14) then there is: [ ]( ) [ ] [ ] [ ] [ ] 1| 1 1 1, 1 1 = = = + −       −      = +   = =      = = = k k k k k k k prob a d e a e d e a d e a e d e a e d e a d prob a d e d prob d (15) with the single normal equation described in eq. (15), the conditional probability of the point attribute state sk can be calculated. the attribute state value is obtained by the quotient of figure 1. the snesim execution process. g eo lo gi a c ro at ic a geologia croatica 72 / special issue114 two multi-point probabilities, which are crucial to obtaining the conditional probability. therefore, the probability of prob[d=1] can be obtained by calculating the number of repetitions of d in the training image. [ ] ( )1 11 , , , , , ( )= = φ = n n n nprob d h h k k c d n is similar to the derivation of d probability. prob[ak=1, d=1] can also be obtained by calculating the repetitions of ak=1 and d=1 in the training image: ( ) 1, 1= = ≈   k n k n c d prob a d n (16) where ck(dn) represents the number of times the data event is at the centre position, whose attribute is sk, and is repeated in the training image. from the calculation of c(dn) and ck(dn), the probability can be obtained from the search tree. therefore, the mpg method can be used to estimate the point value. the conditional probability distribution of the data event at the point to be estimated is extracted from the search tree before the estimation is performed at location u, and the local conditional probability is calculated for this location. the conditional probability distribution function at the point to be estimated is obtained. if the conditional probability at the point to be estimated is 0, the global probability is extracted, instead of the local conditional probability. if the data event at the point to be estimated rarely appears in the training image, the data point (sample grade point) furthest from the point to be estimated is removed, the number of data events repetitions at the point to be evaluated is increased, and the reliability of the local probability estimation is improved. 2.3.2. snesim improvement in order to achieve accurate ore grade estimation, sample grade values need to be discretized in to multiple intervals. the number of discrete intervals influences estimation accuracy. the training image replaces the variogram in the multi-point geostatistical analysis. training images used in the precious stratified phase model simulation are not suitable for ore grade estimation. therefore, it is important to build a new training image for ore grade estimation. 1. sample processing ore grade value is a continuous variable and can be discretized using the following expression: min max min  − = × −  k p pp rp n p p (17) where p is an arbitrary grade value. pmax is the maximum value of the samples. pmin is the minimum value of the samples. rp indicates an integer up. n is the number of discrete intervals. pk is the discretized grade value. in the estimation, the attribute (s) is divided into k states, where k is equivalent to the number (n) of discrete intervals. the estimation result of continuous variables is still a continuous variable. the probability that the attribute to be evaluated is sk is ck(dn)/c(dn) in mpg. the authors use the combined weighting valu es of s1, s2, ..., sk, ..., sn, and perform inverse discretized processing on the value of the estimated attribute with probability values used as the weights. this process can be expressed as: ( ) ( ) ( ) k 1 max min max min min c 2 = × − = × − + − × × ∑ n n k k e n d p p p p p p p c d n n (18) where pe is an estimation grade. n is the number of possible values of the estimation point, which is the same as the number of discrete intervals. pk is the grade value that may be obtained. in theory, more discrete intervals lead to more accurate estimates. in fact, too many discrete intervals will reduce the matching rate between data events and data patterns, which reduces estimation accuracy. multiple discrete interval schemes are used to evaluate the estimated effects and select the optimal estimates in subsequent studies. 2. directional problems and improvements in data event matching the data template shown in fig. 2. is used in multi-point geostatistical estimation. according to the snesim method, the estimation works by matching the six samples closest to the point to be estimated with six ore grade data (data pattern) obtained from scanning the training image; however, u1, u2, ..., u6 are directional in the data template (fig. 2), and it is not appropriate to only consider the 6 closest points to match the data pattern. therefore, the authors consider the directional characteristics of the data event and samples. the estimation searches for more surrounding data, matches the data event direction with the template direction, and discards the samples with poor matching in some directions. the data template uses six data points corresponding to the six directions, which are the positive and negative directions of x, y, and z, respectively. (1, 0, 0), (-1, 0, 0), (0, 1, 0), (0, -1, 0), (0, 0, 1), and (0, 0, -1) indicate the 6 directions in the template. the vector hα (α=1, ..., n) is used to indicate the directionality of the data. the six data points from the n dataset that best match the six directions in the template are selected for the estimation. matching a single data with one direction of the template is written as: [ ] ( )( ) ( ) ( ) 3 1 3 32 2 1 1 , = = = − − = − − ∑ ∑ ∑ j j j j j j j h h l l corr h l h h h l (19) where corr[h,l] represents the relationship coefficient between data events and the data template in a certain direction. hj and lj indicate the three-dimensional coordinates of the data points in the data event and data template, respectively. h and l are the average values of hj and lj. 3. data template and training image previous studies concerning the influence of the data template size on estimation results have shown that large data templates do not significantly contribute to improving the estimation accuracy (hu & chugunova, 2008). therefore, a small data template is used in this study to save computing time (fig. 2). the data template is used to scan the training image of porcelain clay to obtain the corresponding data pattern and store it in the search tree. according to the snesim method, the estimation principle is shown in fig. 1. local conditional probabilities are obtained by matching data events and data patterns. monte carlo sampling is then used to determine the point value to be estimated. points for which the conditional probability distribution cannot be obtained by matching, are estimated from the global probability using the monte carlo sampling method. in practice, the number of data events that do not get a conditional probability by matching with the model is relatively small. in this case, using the global probability instead of the local conditional probability is g eologia c roatica song et al.: multi-point geostatistics for ore grade estimation 115 likely to introduce errors into the estimation; therefore, the study uses the idw method to estimate points not matched by the model and compensate for the uncertainty caused by global proba bility sampling. this method can also be regarded as a hybrid estimation method (m-i) of the mpg and the idw. the authors use the m-i, idw, and ok methods to estimate the li2o and ta2o5 grades in porcelain clay and compare the estimation results with the sample grade by comparing deviation, trend, and variogram analyses. in the estimation process, the established 3-dimensional ore body model is used, and the block unit (block model) is divided based on the ore body model to store the estimated ore grade information. the block model and drill sample information are exported and saved in .txt format. matlab is used to read block information, implement the above estimates, and output the results. 3. study area an introduction to the regional geology, deposit geology, and ore grade characteristics of the porcelain ore mining areas is presented. 3.1. regional geology of the study area the study area is located in the transition zone between the yangtze and south china fold systems. the jiuling uplift comprises the northern part of the study area, the central part is the pingle depression and the south is the wugong uplift. the uplift and depression contain two regional fault zones. the yifeng-jingdezhen and pingxiang-guangfeng faults control the distribution characteristics of the stratigraphic facies, magmatic rocks, and minerals in the area. 3.1.1. stratum the jiu-ling uplift, located within the jiu-gang uplift, is a set of large-scale oceanic turbidite deposits more than 2,000 metres thick composed of volcanic sediments. the sinian system in the wugong uplift is a series of siliceous iron-bearing rocks with low-grade metamorphosed sandstone and siltstone with mudstone and conglomerate. the thickness of the sinian system is 2000-10000 metres. located on both sides of the pingle depression and the uplift area, the devonian-triassic system is composed of a set of marine carbonates and terrigenous clastic sedimentary deposits, with a thickness of 3000-4000 metres. the fault basin next to the shenda fault contains red clastic rocks and basalt with a thickness of 5000-7000 metres. 3.1.2. construction the study area is located in the southwestern jiuling-mekongshan thrust belt and the southern wing of the jiuling compound anticline. it is located between the yifeng-jingdezhen deep fault zone a buried one and the tongguxixiang-fengxinshangfu fault. the jiuling uplift in the study area is composed of tight line ar and double inverted folds. fold axes trend northeast accompanied by a large-scale ductile shear zone. the fault structure is developed, and there are three large-scale faults in the north-north-east, north-east, and north-west directions. most of the faults are pre-ore-formation structures, and the north-east and north-northeast faults have associated mineralization. in the yanshanian period, rare metal ore-bearing hydrothermal fluids altered the alderite-type lithium-bearing porcelain ore body. 3.1.3. magmatic rocks from the proterozoic to the mesozoic, there has been abundant sub-magmatic activity, especially the yanshanian magmatism associated with minerals containing w, sn, and rare earth elements (rees). due to the multi-stage nature of the magmatic activity, ore bodies commonly formed in complex rock masses or complex rock belts in the jurassic or early cretaceous. the east channel of the yifeng county-gaoling-baishuidong area is a complex rock belt dominated by middle to late jurassic rocks. the lithology of the lithium-bearing porcelain ore body in this area is medium-fine-muddy-sodium feldspar-granite, and the genetic type is an altered alderite-type alkaline granite. in addition, a variety of associated rock drips and veins are developed in the area. 3.2. porcelain clay area geology the mining area, located in the jiu-gang uplift, has a complex lithology. magmatic rocks are widely exposed in the mining area. two lithium-bearing porcelain ore bodies exist in the mining area, named li-1 and li-2. li-1 is the main ore body and is located in the eastern part of the mining area. li-2 is a sub-mineral body located in the western part of the mining area. the ore bodies occur in the shape of irregular veins or long strips, and the overall trend is approximately north-south. the ore bodies trend to the south, and the dip angle is steep and irregular. the surface of the f3 fault in the mining area is about 150m at the surface of the 1624 line, and the drilling control tends to be about 180m long. west of the f3 fault, the surface of the 12-0 line shows a width of approximately 150m, and the western end extends for 1000m and becomes thinner in the vicinity of the 0 line. the 12-line control tends to be 100m long, and the 0-line control tends to be 30m long. the li-2 ore body runs from the 13th to the 5th line in the southeast-northwest direction. the mineralization is uneven, showing irregular veins trending north, with an inclination of 45~60° and an alongstrike length of 340m. the northwest mineralization is wide, and it is cut off from the southeast by the 5th line. 3.3. three-dimensional geological model 3d geological models are an important way to visualize ore bodi es as well as an important process for future mine resource eva luation. based on existing exploration data from the mining area, a 3-dimensional geological model and a geological database of the porcelain ore body are established (fig. 3). the geological figure 2. data template. g eo lo gi a c ro at ic a geologia croatica 72 / special issue116 database is built with the help of surpac software. establishment of the geological database includes three main processes: data structure construction, exploration engineering data preprocessing, and data importation. after the database is built, a 3d display of the borehole can be constructed. the ore body profile is delineated on the profile of the exploration line formed by the borehole. a 3d ore body model is built through the developed three-dimensional framework of the ore body. the geological database is mainly used to store the acquired exploration engineering data, and the sample grade combination can be performed on the stored exploration engineering data. 3.4. porcelain clay samples firstly, the original li2o and ta2o5 sample grades were combined using the surpac software sample combination tool. the composite sample is finally produced, and the li2o and ta2o5 grades of porcelain clay samples are determined based on the geological database (table 1). fig. 4 and 5 show the li2o and ta2o5 grade histograms, respectively. 4. variogram and training images descriptions of the ore body test variogram calculation using the ok method follow. the fitting parameters of the spherical variogram and fractal variogram are determined. the block model is used as the training image for grade estimation using the mpg method, and block models of different sizes are established to test the effect of block size on the estimation results. 4.1. variogram fitting for porcelain clay the spherical, power function, and fractal models were used to fit the experimental variogram for the sample grade of porcelain clay, and fitting parameters for the li2o and ta2o5 grades in the x, y, and z directions were obtained. in the spherical model fitfigure 3. three-dimensional model of the porcelain clay ore body. figure 4. li2o sample grade distribution. table 1. li2o and ta2o5 grade statistics results of porcelain clay. name min max average variance standard deviation median kurtosis skewness coefficient of variation li2o (%) 0.2343 0.8679 0.51165 0.01193 0.10923 0.5183 -0.1208 -0.0729 0.21349 ta2o5 (10-6) 15.436 99.40 38.935 65.5316 8.09516 38.6467 2.08147 15.5978 0.20791 figure 5. ta2o5 sample grade distribution. table 2. fitting parametersforli2o and ta2o5 grade in the spherical model. name direction c0 c c0+c a li2o x 0.0045 0.0043 0.0088 37.15 y 0.0045 0.0043 0.0088 37.15 z 0.0029 0.0058 0.00087 67.61 ta2o5 x 18.05 48.31 66.36 27.69 y 18.05 48.31 66.36 27.69 z 6.17 51.94 58.11 32.76 g eologia c roatica song et al.: multi-point geostatistics for ore grade estimation 117 ting, the existing spherical model fitting tool in matlab was used. table 2. shows the spherical model fitting parameters for the li2o and ta2o5 grades. table 3. shows fitting parameters for the power function and fractal models. the fractal and power function models were used for variogram fitting. first, the fractal and power function models were converted into logarithmic form. then, the spss tool was used to fit the experimental variogram. table 3. gives the fitting parameters of the fractal and power function models. the fractal model belongs to the variogram model without sill. according to the fitting for li2o grade in the fractal and power function models, the r-square is above 0.89 and the significance (sig.) is below 0.05 in the fractal model; hence, its fit is better than that the power exponential function model. based on the fitting of ta2o5 grade, the fit of the fractal model is better than the spherical model. the r-squares in the x direction and y direction are above 0.78, and the significance is below 0.05. so the fitting effect is acceptable. the r-square of the fractal model is 0.91, and the significance is below 0.05; hence, the fitting effect is better than the spherical model. 4.2. training image construction the training image is a representation of the a priori geological model. previous studies have indicated that a training image can be constructed by unconditional simulations, analog layer simulations, or using digitized images sketched by geologists. it is diftable 3. fitting parameters forli2o and ta2o5grade in the power function model and the fractal model. name direction model model evaluation model parameter r-square f df1 df2 sig. constant b1 b2 li2o x power 0.777 62.888 1 18 0 -5.584 0.217 -fractal 0.894 71.652 2 17 0 -6.049 0.623 -0.074 y power 0.777 62.888 1 18 0 -5.584 0.217 -fractal 0.894 71.652 2 17 0 -6.049 0.623 -0.074 z power 0.899 160.768 1 18 0 -6.487 0.425 -fractal 0.954 174.703 2 17 0 -7.065 0.929 -0.091 ta2o5 x power 0.599 26.925 1 18 0 3.103 0.279 -fractal 0.787 31.429 2 17 0 2.24 1.031 -0.137 y power 0.599 26.925 1 18 0 3.103 0.279 -fractal 0.787 31.429 2 17 0 2.24 1.031 -0.137 z power 0.805 74.218 1 18 0 2.372 0.432 -fractal 0.91 86.075 2 17 0 1.508 1.186 -0.137 figure 6. variogram fitting results of li2o grade. a, b, and c are the fit using the spherical model in the x, y, and z directions, respectively. d, e, and f are the fit using the fractal model in the x, y, and z directions respectively. g eo lo gi a c ro at ic a geologia croatica 72 / special issue118 ficult to directly determine the grade distribution pattern of the ore body in grade estimation. it is important to establish a simple and effective training image for ore body grade estimation; therefore, the authors assign the sample point grade to the nearest block in the block model and build a 3-dimensional training ima ge based on the block model. the establishment of the block model is primarily accomplished by selecting the block range, determining the block size, adding block attributes, adding block constraints, and block assignment. the block range in this study should be slightly larger than the ore body range. a block model is constructed using a variety of block sizes (table 4). block assignments are primarily determined using the nearest distance method. table 4. shows the block size parameters in five training images. this study uses multiple training images to obtain several estimated grades and determines the optimal li2o and ta2o5 grade estimation parameters. the block size in figs. 7. and 8. is 150m × 75m × 4m. the length, width, and height of the training images of porcelain clay are 1050m, 675m, and 224m, respectively. figs. 8. and 9. are training images of li2o and ta2o5, respectively. figure 7. variogram fitting results of ta2o5 grad. a, b, and c are the fit of the spherical model in the x, y, and z directions, respectively. d, e, and f are the fit of the fractal model in the x, y, and z directions, respectively. table 4. block sizes of training images (pixel number). image name image 1 image 2 image 3 image 4 image 5 x-direction (m) 75 75 75 38 38 y-direction (m) 150 75 75 75 75 z-direction (m) 4 4 2 4 2 figure 8. li2o training image. g eologia c roatica song et al.: multi-point geostatistics for ore grade estimation 119 5. estimation results and analysis the estimated features from the m-i method were analyzed, and optimal estimation results for li2o and ta2o5 determined. the estimation result of the m-i method was compared with the idw and ok methods. the optimal estimation results of li2o and ta2o5 grades of porcelain clay using the idw, ok, and m-i methods were compared. the deviations, trends, and variogram analysis were examined in order to estimate ore grade quality. figure 9. ta2o5 training image table 5. estimated grade statistics for li2o. training images discrete intervals min (%) max (%) average (%) variance standard deviation median kurtosis skewness coefficient of variation image 1 4 0.277 0.824 0.480 0.012 0.112 0.472 -0.030 -0.909 0.233 6 0.277 0.824 0.483 0.011 0.104 0.498 -0.220 -0.451 0.215 8 0.274 0.824 0.485 0.012 0.107 0.512 -0.423 -0.464 0.221 10 0.266 0.824 0.487 0.010 0.101 0.484 0.037 -0.610 0.207 12 0.261 0.824 0.488 0.010 0.101 0.495 -0.106 -0.545 0.208 14 0.277 0.824 0.485 0.011 0.105 0.483 -0.137 -0.660 0.216 image 2 4 0.277 0.798 0.477 0.012 0.108 0.472 -0.035 -0.766 0.228 6 0.277 0.824 0.486 0.012 0.110 0.498 -0.153 -0.437 0.226 8 0.274 0.824 0.488 0.012 0.110 0.512 -0.344 -0.390 0.225 10 0.266 0.824 0.497 0.011 0.103 0.519 -0.100 -0.462 0.206 12 0.274 0.824 0.489 0.010 0.102 0.517 -0.171 -0.595 0.208 14 0.277 0.824 0.490 0.011 0.106 0.498 -0.192 -0.625 0.216 image 3 4 0.314 0.798 0.481 0.011 0.107 0.472 -0.084 -0.743 0.223 6 0.277 0.824 0.487 0.012 0.108 0.498 -0.244 -0.438 0.222 8 0.274 0.824 0.484 0.012 0.111 0.512 -0.241 -0.432 0.230 10 0.266 0.818 0.496 0.010 0.101 0.519 -0.145 -0.650 0.203 12 0.277 0.824 0.490 0.010 0.102 0.525 -0.279 -0.590 0.207 14 0.277 0.824 0.489 0.011 0.106 0.520 -0.273 -0.679 0.217 image 4 4 0.277 0.798 0.483 0.012 0.112 0.472 -0.051 -0.845 0.231 6 0.277 0.824 0.482 0.013 0.113 0.498 -0.116 -0.614 0.234 8 0.274 0.828 0.490 0.013 0.114 0.512 -0.147 -0.082 0.233 10 0.266 0.836 0.497 0.010 0.101 0.519 -0.151 -0.440 0.204 12 0.277 0.842 0.489 0.010 0.101 0.518 -0.169 -0.493 0.206 14 0.277 0.824 0.489 0.011 0.105 0.503 -0.201 -0.591 0.215 image 5 4 0.314 0.798 0.484 0.012 0.109 0.472 -0.091 -0.834 0.225 6 0.277 0.824 0.486 0.012 0.111 0.498 -0.240 -0.584 0.228 8 0.274 0.824 0.484 0.013 0.113 0.512 -0.247 -0.479 0.233 10 0.266 0.836 0.496 0.010 0.101 0.519 -0.123 -0.662 0.205 12 0.277 0.842 0.491 0.010 0.102 0.525 -0.286 -0.544 0.208 14 0.277 0.845 0.491 0.012 0.109 0.524 -0.143 -0.433 0.221 g eo lo gi a c ro at ic a geologia croatica 72 / special issue120 5.1. estimation results firstly, the estimation results of the m-i method using different training images were calculated, and the optimal estimation results determined. similarly, the optimal results of li2o and ta2o5 estimated using the idw and ok methods are given. 5.1.1. m-i estimation results li2o and ta2o5 grades in porcelain clay ore were evaluated using the m-i method. the estimation characteristics of the m-i method were analyzed using the deviation between valuation grade and sample grade. 1. results and analysis of li2o grade valuation table 5. shows the results of the li2o grade estimation using the m-i method. from the data event and data pattern matching rate in fig. 10, the number of discrete intervals increases, which reduces the successful matching probability. at this time, more data points use the overall probability instead of the local probability in the valuation. in the m-i method, the number of points to be estimated using the idw method increases as the number of discrete intervals increases, which has a gradual upward trend. in terms of influence of the number of pixels in the training image on matching rate, the high-pixel training image has a somewhat improved matching. fig. 11a. shows the minimum deviation in li2o valuation grade. in the m-i method, increasing number of pixels in the training image has no noticeable effect on the estimated minimum deviation. for training image 1 with 12 discrete intervals, the smallest minimum deviation is 11.27%. fig. 11b. shows the maximum deviation in li2o valuation grade. as the number of discrete intervals increases, the maxi-figure 10. data event and data pattern matching rates of li2o. table 6. estimated grade statistics for ta2o5. training images discrete intervals min (10-6) max (10-6) average (10-6) variance standard deviation median (10-6) kurtosis skewness coefficient of variation image 1 4 21.886 88.441 38.460 63.911 8.110 34.785 0.376 0.613 0.211 6 18.287 88.441 37.841 44.640 6.753 36.934 -0.136 3.058 0.178 8 18.145 88.441 38.277 34.898 8.305 38.009 -0.100 5.948 0.217 10 18.016 88.441 37.857 42.792 6.696 38.654 -0.094 3.501 0.177 12 17.586 88.441 38.490 50.829 7.199 39.084 -0.298 2.255 0.187 14 17.279 88.441 38.765 46.878 7.176 39.391 0.169 3.495 0.185 image 2 4 21.886 88.441 37.787 54.518 7.505 34.785 0.401 1.184 0.199 6 18.287 88.441 37.803 48.845 7.027 36.934 -0.272 2.563 0.186 8 18.287 88.441 38.473 43.656 8.562 38.009 -0.023 3.132 0.223 10 18.016 88.441 37.854 50.432 7.139 38.654 -0.516 2.957 0.189 12 17.586 88.441 38.147 56.644 7.562 39.084 -0.605 2.416 0.198 14 17.279 88.441 39.070 46.273 7.139 39.391 -0.107 2.867 0.183 image 3 4 19.167 88.441 37.543 54.591 7.396 34.785 0.402 1.270 0.197 6 18.287 88.441 37.734 44.287 6.695 36.934 -0.098 3.096 0.177 8 18.287 88.441 38.107 40.285 8.115 38.009 0.027 3.705 0.213 10 18.016 88.441 37.966 41.358 6.589 38.654 -0.118 3.410 0.174 12 17.586 88.441 38.150 44.446 6.667 39.084 -0.298 3.251 0.175 14 17.279 88.441 38.483 41.369 6.432 39.391 -0.084 3.854 0.167 image 4 4 24.291 88.441 39.378 91.267 9.559 46.923 -0.448 -1.116 0.243 6 22.433 88.441 38.305 44.749 6.828 36.427 0.677 2.703 0.178 8 18.350 88.441 38.083 46.580 6.928 41.675 -0.093 2.193 0.182 10 18.287 88.441 38.140 45.505 6.818 36.427 -0.349 2.486 0.179 12 18.263 88.441 38.457 42.186 9.487 39.926 -0.072 3.140 0.247 14 18.287 88.441 38.510 44.251 6.818 36.427 0.026 2.582 0.177 image 5 4 24.291 88.441 39.713 90.120 9.499 46.923 -0.497 -1.049 0.239 6 19.167 88.441 37.478 51.473 7.174 36.427 0.362 2.101 0.191 8 18.350 88.441 38.155 50.497 7.205 41.675 0.086 1.928 0.189 10 18.287 88.441 38.048 46.319 6.877 36.427 -0.259 2.543 0.181 12 18.263 88.441 38.096 42.926 8.272 39.926 0.029 2.997 0.217 14 18.287 88.441 38.278 42.450 6.682 36.496 -0.046 2.989 0.175 g eologia c roatica song et al.: multi-point geostatistics for ore grade estimation 121 mum deviation decreases. when the resolution of the training image is high, the decrease in maximum deviation becomes more obvious, indicating that increasing the training image pixels can reduce the maximum deviation. when training image 5 is used and the number of discrete intervals is 14, the smallest maximum deviation is -2.61%. fig. 11c. shows the li2o valuation grade average deviation, indicating that a larger number of training image pixels can reduce maximum deviation. as the number of discrete intervals increases, average deviation decreases first and then increases. an inflection point occurs when the number of discrete intervals is 10. as the matching ratio decreases (fig.10), the number of discrete intervals and estimated deviation will increase. when training image 4 is used and the number of discrete intervals is 10, the smallest average deviation is -2.88%. the deviation of estimated li2o grade standard deviation is estimated using the m-i method (fig. 11d). on the one hand, the deviation of the standard deviation variation trend is affected by the number of discrete intervals; on the other hand, it is affected by the matching rate of data events to data patterns. when training image 5 is used and the number of discrete intervals is 14, the li2o grade minimum deviation using the m-i method is -0.54%. the four graphs a, b, c, and d are the estimated deviations of the minimum, maximum, average, and deviation of standard deviation of the estimated li2o grade, respectively. comprehensive analysis of fig. 11. shows that the m-i method can effectively improve li2o grade estimation, and the number of discrete intervals can improve estimation accuracy. in addition, the excessive number of calculation intervals (10 or more) reduces the valuation effect. when the number of training image pixels is large, the success rate between the data event and data template can be improved, which helps to improve and stabilize the evaluation. the m-i method with training image 5 and 10 discrete intervals has the best evaluation. it is estimated that the minimum deviation of the li2o grade is 13.52%, the maximum deviation is -3.65%, the average deviation is -3.14%, and the deviation of the standard deviation is -7.10%. 2. results and analysis of ta2o5 grade valuation table 6. shows the ta2o5 grade estimated using the m-i method. figure 12. shows the data event and data pattern matching rate for the m-i method. increasing the number of training image pixels can improve the matching rate. the highest number of training image pixels has the highest matching rate, and the training image with the lowest number of pixels has a lower matching rate. upgrading the training image in the ta2o5 grade evaluation can help reduce the use of global probability sampling in the valuation process and thus improve valuation accuracy. li2o grade estimation shows a similar relationship between matching ratio and number of training image pixels. the effect of the training image on matching efficiency is related to the sample distribution form or sampling method. the m-i method is affected by the figure 11. deviation in li2o grade estimation based on integrated approach. g eo lo gi a c ro at ic a geologia croatica 72 / special issue122 sample grade distribution or sampling method when estimating the ore grade. figure 13. presents an analysis of the estimated ta2o5 deviation when using the m-i method. the effect of training image pixels on the minimum deviation is not significant (fig. 13a). after the number of discrete intervals increases, the minimum deviation decreases. when using training image 1, 2, or 3 with 14 discrete intervals, the smallest minimum deviation is 11.94%. figure 13b shows the maximum deviation of the ta2o5 valuation grade. the number of discrete intervals and the pixel size of the training image have no affect on the maximum deviation. the maximum deviation is consistently 11.03%. increasing the number of training image pixels fails to reduce the average deviation (fig. 13c), indicating that the valuation results are affected by the idw method when using the m-i method. the average deviation of the m-i method is smaller than the mpg method, indicating that the m-i method is still superior to the simple mpg method. when using training image 2 with 14 discrete intervals, the smallest minimum deviation is 0.35%. figure 13d. shows the deviation of the standard deviation of the ta2o5 valuation grade. under the m-i method, the deviation of standard deviation fluctuates greatly with the number of discrete intervals. however, compared with the mpg method, the m-i method shows a significant reduction in deviation of the standard deviation. this study concludes that the use of the m-i method, training image 4, and 14 discrete intervals provides the best results. it is estimated that the minimum deviation of the ta2o5 grade is 18.31%, the maximum deviation is -11.03%, the average deviation is -2.15%, and the deviation of the standard deviation is 2.19%. the ta2o5 valuation shows that the m-i method is closer to the figure 12. data event and data pattern matching rates of ta2o5. figure 13. deviation in ta2o5 grade estimation based on integrated approach. g eologia c roatica song et al.: multi-point geostatistics for ore grade estimation 123 sample ta2o5 grade distribution than the mpg method, indicating the m-i method is superior to the mpg method. the m-i method is not scientific and rigorous enough to use global sampling instead of overall sampling for data events that cannot be matched. increasing the number of discrete intervals reduces the matching rate between data events and data templates, which increases the probability of using global sampling to generate local samples. this increases the inaccuracy of the valuation. increasing the number of training image pixels can improve the matching rate to a certain extent but cannot fundamentally solve the problems outlined above. the idw is used instead of the global sample estimate for points that cannot be estimated using local sampling. although the idw method has a certain smoothing effect, its valuation results are better than estimates determined using global sampling. because data events around the point to be estimated cannot be used, it is commonly the case that there is a small probability of data events; therefore, it is unscientific to use global sampling instead of local sampling. the four graphs a, b, c, and d show the estimated deviations of the minimum, maximum, average, and deviation of standard deviation of the estimated ta2o5 grade, respectively. 5.1.2. optimal estimation results the optimal estimated grades of li2o and ta2o5 are shown in tables 7 and 8, respectively. idw1 and idw2 respectively represent the optimal estimation results when the three samples and five samples of li2o and ta2o5 were included in the estimation of idw. optimal estimation results for li2o and ta2o5 grade occurred when using the ok method and when the fractal model is used. when image 5 is used and the discrete interval is divided into 10 pieces, the li2o grade has the best m-i estimation result. when image 4 is used and the discrete interval is divided into 14 pieces, the ta2o5 grade has the best estimation result. 5.2. estimation results analysis a comparison is presented of the estimation method characteristics of the idw1, idw2, ok, and m-i methods. deviation analysis, trend analysis, and variogram analysis were performed on li2o and ta2o5 grades. finally, the advantages of the m-i method were compared with idw1, idw2 and the ok methods. 5.2.1. deviation analysis the estimated deviation of the optimal estimated grade of porcelain clay was analyzed. the minimum deviation of li2o estimated grade ranges from 13.52% to 20.24% (fig. 14). the maximum deviation ranges from 2.47% to 6.30%. the li2o grade estimation minimum deviation is significantly greater than the maximum deviation. estimation results of the idw1, idw2, ok, table 8. optimal estimation results of ta2o5 grade. method min (10-6) max (10-6) average (10-6) variance standard deviation median (10-6) kurtosis skewness coefficient of variation idw1 16.6269 92.9562 38.4829 44.4826 6.6695 38.8171 -0.0167 5.6815 0.1733 idw2 18.3676 84.7443 38.6357 38.5344 6.2076 38.7802 -0.2967 3.4585 0.1607 ok 18.4970 88.6346 38.6976 36.4862 6.0404 38.7437 -0.2018 4.0988 0.1561 m-i 18.2870 88.4411 38.5101 44.2511 6.8176 36.4270 0.0257 2.5824 0.1770 table 7. optimal estimation results of li2o grade. method min (%) max (%) average (%) variance standard deviation median (%) kurtosis skewness coefficient of variation idw1 0.2704 0.8465 0.5000 0.0127 0.1129 0.5101 -0.2713 -0.3560 0.2257 idw2 0.2761 0.8181 0.5001 0.0116 0.1077 0.5224 -0.3394 -0.3547 0.2153 ok 0.2817 0.8133 0.4898 0.0105 0.1026 0.4972 -0.2813 -0.5665 0.2094 m-i 0.2660 0.8362 0.4956 0.0103 0.1015 0.5194 -0.1233 -0.6617 0.2048 figure 15. ta2o5 grade estimation deviation. fig. 14 li2o grade estimation deviation. g eo lo gi a c ro at ic a geologia croatica 72 / special issue124 and m-i methods are similar, indicating that the large minimum deviation is not due to a change in estimation method and the results of the m-i method are accurate. the average deviations of the idw1, idw2, ok, and m-i methods are -2.28%, 2.26%, -4.28%, and -3.14%, respectively. the deviation of the standard deviation of the estimation results of the 4 methods is small. the standard deviation of the idw2 method is the smallest (1.31%). figure 15. shows the estimated deviation of the ta2o5 grade. the minimum deviation of the estimated grade of ta2o5 ranges from 7.71% to 19.83%. the maximum deviation ranges from 6.48% to 14.74%. the average deviation ranges from 0.61% to 1.12%. the ta2o5 grades estimated by the 4 methods are extremely similar. although samples used in the estimation are from the same exploration project, the deviations of the li2o and ta2o5 grades are different for the same estimation methods, indicating that sample grade distribution has an obvious influence on the estimation results. in addition, the estimated deviations of the 4 methods are very similar for the same grade estimation. this further illustrates that the estimation results of the improved multipoint geostatistics (m-i) are reliable and accurate. 5.2.2. trend analysis trend analysis was performed on the li2o and ta2o5 estimated grades for porcelain clay. figure 16. shows the trend of the li2o grade change with elevation. overall, the estimated ore grade is lower than the actual ore grade. the li2o grade at the shallow (large) elevation of the ore body is higher than the deep (small elevation) grade. the li2o grades estimated by the idw1, idw2, ok, and m-i methods have greater consistency with the elevation trends, and the estimated grades for the different methods are similar. figure 17. shows the trend of the ta2o5 grade with figure 16. trend analysis of li2o grade. figure 17. trend analysis of ta2o5 grade. figure 18. variogram analysis of li2o grade. a, b, and c are the variograms of the estimated and sample grade in the x, y, and z directions, respectively. g eologia c roatica song et al.: multi-point geostatistics for ore grade estimation 125 elevation. the ta2o5 and li2o estimation trends are similar. the li2o and ta2o5 grade is greater at higher elevation (shallow) than at lower elevation (deep). 5.2.3. variogram analysis the variograms of the estimated grade and sample grade of li2o and ta2o5 are shown in figures 18. and 19. the idw1 method used 3 samples in the estimation process. the idw2 and ok methods used 5 samples. the number of samples included in the estimation using the idw method in the m-i method is 4. the largest difference between the li2o estimated grade and sample grade variograms is in the x and y directions for the idw2 method. the ok method has the second largest gap. the variogram based on the idw1 method is closer to the sample grade than the m-i variogram. that is to say that the idw1 variogram is closest to the sample grade in the x and y directions. in the z direction, the difference between the li2o ok variogram and the sample grade variogram is the largest. the second largest gap is in the idw2 variogram. similarly, the idw1 li2o grade estimated is closest to the sample grade, followed by m-i. the li2o variograms indicate that the number of samples participating in the estimation has important effect on the estimated grade variogram. variograms of the estimated ta2o5 grade differ greatly from the sample variogram (fig. 19). the difference among the estimated grade variograms is small. the ok and idw2 variograms are similar, and the idw1 and m-i variograms are also similar. the idw1 and m-i variograms are slightly more similar than the ok and idw2 variograms. overall, the variograms of the estimated grade are significantly lower than that of the samples. the idw2 and ok estimated grades have a stronger smoothing effect. although the li2o and ta2o5 samples are from the same exploration project, the gap between the estimated variograms and sample variograms is different, indicating that the sample grade distribution has an effect on the morphology of the variogram. comprehensive analysis of the li2o and ta2o5 grade variograms indicates that the greater the number of samples participating in the estimation, the larger the difference between the sample grade variogram and the estimated grade variogram will be. if the same number of samples participate in the estimation, the estimation result of the ok method has a higher smoothness than that of the idw2 method. if the number of samples participating in the estimation increases, the variogram of the idw estimated grade becomes smoother. the sample distribution significantly inf luences the estimated grade variogram. the estimated grade for the m-i method is similar to that of the idw and ok methods, indicating that the ore grades estimated by the multi-point geostatistical method are reliable and accurate. 6. discussion valuation using the m-i method indicates that improving the training image resolution can improve the mpg valuation to some extent. however, increasing the training image resolution seriously affects the computational efficiency and does not completely solve the problem of matching between data events and data patterns. matching efficiency between the data events and data patterns is an important factor affecting the accuracy of multi-point geostatistical estimation. in theory, increasing the number of discrete intervals can improve valuation accuracy, but it will reduce the matching rate between data events and data patterns, which affects valuation accuracy. the m-i method can overcome the issue of inaccurate low-frequency grade information in mpg estimation. the study produced the optimal results for different training images and discrete interval numbers when estimating using the m-i method. this study evaluated the grades of li2o and ta2o5 in porcelain clay using an improved mpg method. results were compared with results from the ok and idw method, demonstrating the feasibility, reliability, and accuracy of the m-i method for ore grade estimation. the stability and accuracy of multi-point geofigure 19. variogram analysis of ta2o5 grade. a, b, and c are the variograms of the estimated and sample grade in the x, y, and z directions, respectively. g eo lo gi a c ro at ic a geologia croatica 72 / special issue126 statistical estimation indicates that the new training image construction method is feasible. compared with the ok method, the use of training images instead of variograms improves the utilization efficiency of sampling information. in other words, informational relationships between more samples are utilized. the improved method is theoretically superior to variograms that only utilize the pattern of information between two samples. this study used deviation, trend, and variogram analyses to analyze the improved mpg method estimation features from different angles. it proves that the new training images improved data event matching methods, and the uncertainty problem processing methods can meet the requirements of ore grade estimation. an accurate estimate of the li2o and ta2o5 ore grades was achieved. 7. conclusion (1) this study introduced mpg into the field of ore grade estimation, provides a new training construction method, and applies it to li2o and ta2o5 ore grade estimation in a porcelain clay deposit. a good estimation result is obtained using the m-i method. (2) the matching of data events and data patterns was improved. a new matching method was used to account for the directionality of the data template. the inverse distance weighted method was used to compensate for the lack of mpg. the improvements enhance the reliability of mpg estimates. (3) this study produced the optimal estimation results for li2o and ta2o5 when the idw, ok, and m-i methods were used. the grade distribution pattern is the main factor affecting the minimum and maximum deviation. if more samples are included in the estimation, the estimation results of the idw and ok methods will be smoother. (4) deviation, trend, and variogram analyses were used to study the estimated features of the inverse distance weighted, ordinary kriging, and multi-point geostatistics. the reliability and accuracy of the m-i estimations is shown by comparing the estimations of the idw and ok methods. acknowledgement the funding was provided by the china national natural science foundation (no. 71363040). references abdollahifard, m.j. & nasiri, b. (2017): exploiting transformation-domain sparsity for fast query in multiple-point geostatistics.– computational geosciences, 21/2, 1–11. doi: 10.1007/s10596-016-9612-1 burc arpat, g. & caers, j. (2007): conditional simulation with patterns.– math. geol., 39/02, 177–202. gao, s.c., tian, m. & sun, z. (2016): multiple-point geostatistics modeling factors analysis and optimization by using markov chain model.– mathematics in practice and theory, 46/0, 202–211. gardet, c., ravalec, m.l. & gloaguen, e. (2016): pattern-based conditional simulation with a raster path: a few techniques to make it more efficient.– stoch. env. res. risk. a., 30/2, 429–446. doi: 10.1007/s00477-015-1207-1 geiger, j., jakab, n., csökmei, b., horváth, z. & gellért, b. (2016): statistical and geostatistical study of rn and hydrocarbon components of a soil gas monitoring system: an application to surface hydrocarbon exploration.– geologia croatica, 69/2, 255–268. doi: 10.4154/gc.2016.21 hansen, t.m. & le, t.v. (2016): bach t. mpslib: a c++ class for sequential simulation of multiple-point statistical models.– soft. x., 5, 127–133. hu, l. y. & chugunova, t. (2008): multiple-point geostatistics for modeling subsurface heterogeneity: a comprehensive review.– water. resour. res., 44, 1–14. doi: 10.1029/2008wr006993 huysmans, m., orban, p. & cochet, e. (2014): using multiple-point geostatistics for tracer test modeling in a clay-drape environment with spatially variable conductivity and sorption coefficient.– math. geosci., 46, 519–537. doi: 10.1007/s11004-013-9502-1 kumari, m. & singh, c.k. (2018): gariro: gradient and residual integrated rank ordering of stations in rainfall monitoring network.– earth. sci. inform., 11, 1–14. doi: 10.1007/s12145-018-0332-z li, z.l., wang, p. & zhang, x.l. (2008): improvement and application of inverse distance weighted method.– met. min., 02, 88–92. luo, h.m., yang, p.j. & wang, c.j. (2015): litho facies simulation based on multiple-point geostatistics multiple data joint constraints.– oil geophysical prospecting, 50/01, 162–169+19. novak zelenika, k., vidaček, r., ilijaš, t. & pavić, p. (2017): application of the deterministical and stochastical geostatistical methods in petrophysical mode ling, case study upper pannonian reservoir in sava depression.– geologia croatica, 70/2, 105–114. doi: 10.4154/gc.2017.10 straubhaar, s., renard, p. & mariethoz, g. (2016): conditioning multiplepoint statistics simulations to block data.– spatial statistics, 16, 53–71. doi: 10.1016/j.spasta.2016.02.005 strebelle, s. (2001): sequential simulation drawing structures from training images.– palo alto, phd thesis, faculty of science, stanford university. vries, l.m.d., carrera, j. & falivene, o. (2009): application of multiple point geostatistics to non-stationary images.– math. geosci., 41/1, 29. doi: 10.1007/ s11004-008-9188-y wang, g.w., feng, y. & carranza, m. (2016): typomorphic characteristics of pyrite: criteria for 3d exploration targeting in the xishan gold deposit, china.– j. goechem. explor., 164, 136–163. doi: 10.1016/j.gexplo.2016.01.003 wu, t. & fu, b. (2016): application of the multiple-point method to geological modeling in the sulige gasfield.– geol. prospect., 52/05, 985–991. yang, p.j. (2014): geostatistics inversion from two-point to multiple-point.– chin. j. geophys. progr., 29/05, 2293–2300. yin, y.s., wu, s.h. & zhai, r. (2008): the forecasting of fluvial facies reservoir distribution by using simpat.– j. southwest petrol. univ., 02, 19–22+184–185. yin, y.s., wu, s.h. & zhang, c. (2008): m. multi-point geostatistical method based on reservoir skeleton.– sci. china ser. d., s2, 157–164. yu, s.y., li, s.h. & he, y.b. (2016): multiple-point geostatistics algorithm bases on pattern scale-down cluster.– acta. petrol. sinica, 37/11, 1403–1409. zhang, t., bombarde, s. & strebelle, s. b. (2006): 3d porosity modeling of a carbonate reservoir using continuous multiple point statistics simulation.– spe journal, 11/3, 375–379. doi: 10.2118/96308-pa zhang, t., du, y. & husng, t. (2015): a reconstruction method for spatial data using parallel snesim.– j. comput. dev., 52/06, 1431–1442. zuo, c., teng, q.z. & he, x.h. (2016): a fast 3d reconstruction algorithm of multiple point statistics.– j. sichuan univ: natl. sci. ed., 53/02, 337–346. author contributions statement: yu-chen song designed the experiment, zhan-ning liu performed the experiment and wrote the paper, xiao-yan yu processed the data and images, and hai-dong meng revised the paper. competing interests statement: the authors declare that there are no competing interests between them, including financial and non-financial interests. 2020 | 73/3 | 131–142 | 12 figs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the middle devonian to early carboniferous turbiditic siliciclastic succession of the central part of the carpatho-balkanides of serbia is classically interpreted as the kučaj-zvonce flysch (maslarević & krstić, 1987a). in addition to previously documented sedimentological data from several localities in serbia (e.g. krstić, 1984; krstić et al., 2004, 2005), the concept of extrabasinal turbidites (zavala & arcuri, 2016) produced under hyperpycnal flows is discussed as an additional point to the overall interpretation of the system. as the hyperpycnal flows occur during high river discharge into the basin they represent an efficient mechanism of transfer of clastic material from continental environments to the deep-marine realms (mulder & syvitski, 1995). the characteristics of hyperpycnites (deposits of hyperpycnal flows) are distinctive both in their sedimentological features (mulder et al., 2003) and palaeontological content (zavala et al., 2012). these diagnostic criteria were used to indicate the presence of hyperpycnites within the turbidites of the kučaj-zvonce flysch. the characteristics of the kučaj-zvonce flysch were studied at the kostadinovica quarry in which 31.75 m of the siliciclastic succession is exposed. analyzed sedimentary features were used for the determination of lithofacies and their internal relationships. observed sedimentary characteristics along with palaeontological material from the site were further compared to criteria for the genetic model of extrabasinal turbidites (zavala & pan, 2018) with the aim of better understanding the processes controlling the deposition. the age of the studied succession at kostadinovica has not been determined more precisely by previous studies due to the lack of biostratigraphic indicators from the site but has rather been derived from comparison of the lithostratigraphic characteristics with other localities (veselinović et al., 1964a). pioneering palaeobotanical data from the devonian of the carpatho-balkanides (pantić, 1960) was often used as one of the age criteria hyperpycnites within the devonian-carboniferous flysch of the carpatho-balkanides (kostadinovica, eastern serbia) miloš radonjić university of belgrade, faculty of mining and geology, department of regional geology, kamenička 6, 11 000 belgrade, serbia; (milos.radonjic@rgf.bg.ac.rs) doi: 10.4154/gc.2020.13 abstract this study presents new discoveries of vascular plants and the trace fossil dictyodora liebeana (geinitz) from the devonian–carboniferous kučaj-zvonce flysch of the carpatho-balkanides and the implications of this fossil association for its sedimentary setting. the occurrence of the described plant debris in a deep-marine environment indicates the presence of hyperpycnites within the siliciclastic turbidites exposed at the kostadinovica locality. the sedimentological data and the characteristics of the fossil material support the proposed model in which the sediment was at least partially transported by hyperpycnal currents. furthermore, based on the assessment to similar palaeofloras from comparable formations, the age of the fossil plants can be determined as early carboniferous. this can be used as an additional biostratigraphic criterion given the relative abundance of vascular plants in other localities of the kučaj-zvonce flysch described in previous studies. the age and the depositional setting of the succession is further better constrained by the first observation of dictyodora liebeana (geinitz) in the carpathobalkanides of serbia. for similar occurrences of the kučaj-zvonce flysch, while in most cases the age has been broadly determined as devonian. the proposed devonian age of the kostadinovica succession was likewise set earlier based on the relatively abundant vascular plants from the site (krstić, 1984). this paper presents the first discovery of the trace fossil dictyodora liebeana (geinitz) from the carpatho-balkanides of serbia which is used both as an indicator for a deep-marine depositional environment and also to propose an early carboniferous age for the succession. furthermore, the collected palaeobotanical material is compared to similar mississippian floras of europe. based on the studied sedimentary features and the position and mode of preservation of the palaeontological material, the kostadinovica succession is interpreted as an distal part of the turbidite system with the occurrence of hyperpycnites. the detailed discrimination between depositional sequences (turbidites versus hyperpycnites) resulting from their fundamentally different modes of transport was limited by the insufficient quantity of the obtained sedimentological samples. this led to the use of fossils as an indicator of hyperpycnal transport. the presented study could be used as a starting point for a more detailed petrological analysis of the provenance of the detrital components combined with palaeogeographical information. a further aim should be a reconstruction of the hinterland area of the system which is also lacking at present. although the framework of the devonian/carboniferous flysch systems of se europe was developed and compared at regional scales (ebner et al., 2008; vozárová et al., 2009), local studies in the carpatho-balkanides could lead to a better understanding of the kučaj-zvonce flysch and its position and correlation to other equivalent formations of the variscides of europe. 2. geologic setting the studied succession at the kostadinovica locality is positioned in the central part of the carpatho-balkanides in eastern serbia article history: manuscript received april 15, 2020 revised manuscript accepted august 25, 2020 available online october 22, 2020 keywords: mississippian flora, dictyodora liebeana (geinitz), hyperpycnites, kučaj-zvonce flysch, carpatho-balkanides g eo lo gi a c ro at ic a geologia croatica 73/3132 emphasized examples of the tbcd, tabcd and tbcde intervals as a general trend for this unit (krstić et al., 2008). among other sedimentological constituents of the flysch, lower carboniferous limestone olistosromes of cm to m dimensions were discovered (maslarević & krstić, 1987b). the kučaj-zvonce flysch is unconformably overlain by upper carboniferous continental deposits, permian red sandstones and mesozoic-palaeogene sedimentary cover (krstić & maslarević, 1990). 3. the kostadinovica section the exposed succession at the kostadinovica locality (wgs: 43°43’5.06” n; 21°56’38.90” e) is in probable tectonic contact with cretaceous carbonates and oligocene(?) siliciclastics towards the ne side of its exposure while the neogene sediments of the sokobanja basin transgressively overlie it towards the sw (fig.1c). the kostadinovica quarry exposes some 31.75 m of the siliciclastics sequence (fig. 2). in the field, the observed rocks were categorized predominantly as siltstones to medium-grained sandstones (stow, 2005). the sandstones are mostly very fineto medium-grained greywackes (krstić, 1984). grains are relatively poorly sorted and composed mainly of quartz, feldspars and lithic fragments. finer rocks are represented by siltstones or mudstones. way up criteria (primarily the fining upward trend of grain size, relations of erosive/gradual transitions and the relationships of cross-lamination within beds) were used to recognize the (fig. 1a, b). in terms of the alpine orogeny, the kučaj-zvonce flysch is part of the basement of the getic unit (i.e. kräutner & krstić, 2002; krstekanić et al., 2017; schmid et al., 2020) or the locally termed kučaj zone (dimitrijević, 1997). the kučaj zone is characterized by magmatic rocks and sedimentary formations with diverse histories both in terms of metamorphism and tectonics. the oldest formations belong to the proterozoic-cambrian crystalline metamorphics of the homoljske mts. in the northern part of the unit (dimitrijević, 1997). the overlying deposits represent a siliciclastic cycle of sedimentation with a trend of deepening of the facies beginning with early ordovician coastal/shallow marine siliciclastics which pass into deep basinal silurian to early devonian fine-grained graptolite schists (krstić & maslarević, 1990). the devonian (late lochkovian to late frasnian) pre-flysch is defined as channeled slope facies with the addition of hemipelagic shales, cherts and limestones (krstić et al., 2004) which terminates with dolomitic limestones containing conodonts of the gigas and linguliformis zones of the late frasnian (krstić & sudar, 1989). the deposition of the kučaj-zvonce flysch lasted from the late devonian (late frasnian) to the early carboniferous (viséan) as a part of the circum pannonian flysch system (ebner et al., 2008). the kučaj-zvonce flysch was interpreted as a retrograding system of deposits of the slope to mid-fan and the outerfan to basin tract (krstić et al., 2004). the bouma divisions were used for the description of the sedimentary sequences with figure 1. the position of the kostadinovica section. (a) outline of se europe and the position of the carpatho-balkanides in serbia. (b) tectonic units of the carpatho-balkanides (modified after kräutner & krstić, 2002). (c) geological sketch map of the studied area (modified after veselinović et al., 1964b; kräutner & krstić, 2003). arrow indicates the position of the studied section. figure 2. the siliciclastic succession in the kostadinovica quarry. the letters a – d mark the interpreted units while white lines indicate their boundaries. fault systems (fss – strike-slip fault zone; fn – gravitational faults) are marked in red. white arrows point toward the position of figures presented in this paper. photo taken during august 2019. g eologia c roatica radonjić miloš: hyperpycnites within the devonian-carboniferous flysch of the carpatho-balkanides (kostadinovica, eastern serbia) 133 stratigraphic order. the bedding monotonously dips towards the ssw (dip direction ~210–235°) at an angle of 40 to 50°. variations of the dip directions of bedding planes and their dip angles are due to the deformed state of the whole unit. deformational fabrics are composed of a series of cleavages which significantly disrupt the primary sedimentary structures. development of several orientations of cleavage planes led to unfavourable conditions for study at the outcrop (i.e. a limited potential to trace lateral continuation of bedding, brittle deformation in fine-grained rocks, etc.). furthermore, the middle part of the succession is truncated by a system of brittle, dextral strike-slip faults (fss in fig. 2). movement along these faults can be concluded based on the riedell’s plains and folding related to the faulting process. the amount of displacement along the fss system could not be established with precision but is probably in the range of several metres and it does interrupt the superposition of the succession in its central part. the strike of several of the most prominent fss fault planes is oriented in a nw – se direction (~ 310-130°) with a steep dipping angle (~80° to vertical). a second group of observed faults has a more localized influence on the succession. these faults (fn in fig. 2) have normal movements and are related to the fss fault zone probably as a part of a transtensional system. as the excavation works in the quarry progressed, different levels of the succession were exposed and studied. based on the sedimentary characteristics, the kostadinovica succession was subdivided into four units: a, b, c and d (fig. 2). the observed sedimentological data from the section was used for the construction of a local sedimentological column (fig. 3). 3.1. unit a (interval: 0 to 2.10 m of the column) stratigraphically the lowest unit (a) of the succession is exposed in the ne side of the quarry and is composed of a series of normally graded turbidites (fig. 4). their lower parts are composed of fineto medium-grained sandstones which pass into siltstones and have thicknesses of up to 35 cm. the thickness of sandstone layers ranges from ~5 cm to ~20 cm, decreasing up-section. the main internal depositional structures in the sandstone layers are parallel lamination beginning from the sharp, erosional lower surface of the bed passing into either a structureless interval or an interval with wavy lamination and then a gradual transition into siltstone (i.e. layer a3). alternatively, layer a4 comprises of fining upward sandstone with parallel lamination which passes into a level with hummocky-like lamination with a sharp transition into siltstones. finer-grained members make up the upper levels of sequences which are usually organized into delicate parallel lamination composed of mica grains or apparently structureless intervals. 3.2. unit b (interval: 2.10 to ~ 15 m of the column) a gradual change of sedimentary characteristics occurs above the 2.10 m mark of the column and is represented by an increase in thickness of the siltstone intervals which comprise the lower part of unit b. sedimentary structures of the finer-grained interfigure 3. a sedimentological column of the kostadinovica succession. grain size is shown on the right-hand side of the column (si – siltstones, f – finegrained sandstone, m – medium-grained sandstone, c – coarse-grained sandstone). the sedimentary sequences or beds are designated by the letter of the unit and a number. the sedimentary structures are marked by gray boxes within corresponding columns (1 – normal grading, 2 – planar lamination, 3 – hummocky-type lamination, 4 – convolution, 5 – structureless intervals). the fossils within beds or sequences are marked by letters p (plants) and i (ichnofossils). interpreted units are marked by capital cursive letters a – d. all units correspond to compared facies families of the hyperpycnite tract (after zavala & pan, 2018; see fig. 11. for details). facies family abbreviation: s – suspended load facies; l – lofting facies. figure 4. sedimentary characteristics of unit a of the kostadinovica section. g eo lo gi a c ro at ic a geologia croatica 73/3134 vals of this unit are obscured by cleavage, but wavy and rhythmic parallel lamination is recognized along with minute variations of grain size of the different lamina. sandstone layers appear either as intervals of graded turbidite units or solitary structureless beds. turbidite beds are similar in appearance to unit a while structureless sandstone beds have sharp bottom and top surfaces. above the 4.70 m mark of the column a zone of fracturing (fn) begins which disrupts the bedding for the next 6 m making observations at this level challenging. nevertheless, several beds show sedimentary characteristics which could be discussed out of the superpositional context since the overall characteristics of the deformed rocks are similar to the previous level of unit b. bed b11 (fig. 5a) begins with a fining-upward sandstone with parallel lamination followed by a fine-grained sandstone with hummocky-type lamination. next, a fine-grained sandstone interval shows convolute lamination. the convolute lamination appears in several other solitary beds within this level (i.e. b15). the fining upward sandstone to siltstone beds within unit b occur irregularly compared to unit a (beds b18, b20, etc.). the zone of fracturing fades at the about the 8 m mark. above this level, two mediumto coarse-grained sandstone beds (b23 and b25) stand out compared to adjacent lithologic members (fig.5b). internal structures of these beds are not prominent, but a fining upward trend is noted. faint, inclined non-parallel lamination is marked by the accumulation of coarser grains within the matrix. these beds are 50 and 40 cm thick, respecfigure 5. sedimentary characteristics of unit b. (a) fining-upward sequence b11 with convolute interval in its upper part. (b) upper part of unit b near the transition into unit c. two massive sandstone beds are marked as b23 and b25 and are truncated by normal faults (fn). figure 6. sedimentary characteristics of unit c. (a) the central part of unit c showing repetition of thin siltstone and sandstone layers. note that the white colouration on some surfaces is caused by weathering. (b) the lower part of the structureless sandstone bed c20. clay chips are highlighted by white lines. (c) a polished rock slab showing the structures of siltstone and sandstone layers. (d) a thin-section viewed in non-polarized light showing the plant detritus above the parallel laminated siltstones. g eologia c roatica radonjić miloš: hyperpycnites within the devonian-carboniferous flysch of the carpatho-balkanides (kostadinovica, eastern serbia) 135 tively. they contain fragments of coalified plant remains of up to 1 by 5 cm in size which are scattered throughout the beds. cleyey chips with diameter of 2–3 cm are also present. both the lower and upper surfaces of these beds are sharp. beginning approximately from the 9 m mark of the column, a change of the colour of the rocks on a freshly broken surface is evident. the predominant colour of the lithologic members upsection is dark gray compared to the generally light brown to light gray colour of the previously described rocks. coloration of the graded beds up to the aforementioned level is divided into brown to light brown in sandstones and olive gray to gray in fine-grained levels. 3.3. unit c (interval: ~ 15 to 25.25 m of the column) unit c of the section begins above the 15 m mark of the column, from where there is a notable decrease in bed thickness, which on average ranges from 3–5 cm, exceptionally up to 10 cm. a dextral strike-slip fault zone (fss in fig. 2) truncates the unit at about 16 m and offsets the succession for several metres. within this zone, no lateral continuity of the beds could be traced but the lithological characteristics of the rocks are similar to other levels in this unit. unit c comprises repeating thin bedded sandstones and siltstones (fig. 6a, c). grading in the sandstone beds is normal or not visible while sorting of the grains is well to very well developed. internal sedimentary structures are partially exposed in sandstones and are represented by parallel lamination and wavy lamination with a subtle transition between them. convolute lamination intervals occur within the unit at several levels (i.e. bed c7). structureless sandstone beds (up to 5 cm thick) are rare as solitary members with sharp bed boundaries. siltstone intervals display wavy lamination marked by the accumulation of phyllosilicates (fig. 6c, d) or they are structureless. in most cases, the structures of fine-grained rocks are discretely obscured by cleavage. the coarse to medium-grained sandstone bed c20 is located at 21.20 m in the column and is distinctly different from other members of unit c (fig. 6b). this bed is ~40 cm thick and its bottom surface is sharp with possible sole marks. the lower part of the bed appears massive while fining-upward begins in the last ~10 cm of the bed which subtly turns into background sandstone/ siltstone couplets. solitary cm-sized coalified plant remains are scattered throughout the bed. this bed resembles beds b20 and b23 of unit b. dark gray, fine-grained sandstone/siltstone couplets form the next 4 m of unit c. 3.4. unit d (interval: 25.25 to 31.75 m of the column) unit d begins at 25.25 m from the start of the column and is 6.5 m thick. turbidite beds composed of medium-grained sandstones and siltstone/mudstones are the dominant members of unit d (fig. 7a). their characteristics are similar to the turbidite beds in unit a. on average, the sandstone/siltstone sequences are 20 to 35 cm thick. bottom surfaces of the sandstone intervals are sharp and often erosive on the siltstone layer of the previous bed. internal organization of beds (i.e. d7) in this unit is usually characterized by parallel or quasi-planar lamination at the base of the mediumgrained sandstone level which turns massive upward (fig. 7b). the next level is organized into cross-lamination or wavy lamination within fine-grained sandstones which pass gradually into structureless siltstones. cross-lamination in the sandstone intervals varies from hummocky-type to unidirectionally inclined laminafigure 7. sedimentary characteristics of unit d. (a) the transition from unit c into unit d. the change is noticeable in the onset of fining-upward sequences (unit d) compared to sandstone/siltstone repetition (unit c). a gradual change of colour also marks the transition. (b) internal organization of bed d7. the red rectangle is the position of the thin-section in figure 7c. (c) thin-section indicating repetition of upward fining and upward coarsening intervals with intrasequence erosional surfaces. view is in non-polarized light. g eo lo gi a c ro at ic a geologia croatica 73/3136 tion. the siltstone levels in some cases shows delicate parallel or wavy lamination or appear without apparent structures. the parallel lamination in the lower levels of beds in unit d locally contain plant detritus. in one case (bed d7), the internal structure is composed of upward coarsening and upward fining intervals sometimes separated by intrasequence erosional surfaces (fig. 7c). 3.5 palaeontological material the kostadinovica section contains two groups of fossil remains – abundant vascular plant debris and trace fossils. the overall deformation for both burial and the latter tectonic activity of the unit led to and accounts for the unfavourable conditions for fossilization. overall occurrence and distribution of plant fragments and trace fossils was used as a criterion for sedimentologic and stratigraphic interpretation of the studied section and comparison with similar formations. collected samples are stored at the collection of faculty of mining and geology, university of belgrade (labels mrk 1–20). 3.5.1. vascular plants an important feature of the kostadinovica section is the abundance of fragments of vascular plants. plant detritus occurs as accumulations of delicate stem fragments scattered within the lower parts of the sandstone layers (fig. 8). the number of accumulated fragments visible to the naked eye on a single lamina ranges from 12~80 pieces on a surface of 10 cm2. most often, several laminae within the same bed contain detritus accumulations. the lateral extent of the majority of the plant bearing layers could be traced to at least 5-6 m depending on circumstances within the quarry. no sorting of the fragments is observed while the orientation of the longer axis of fragments is generally chaotic. in some cases when the direction of the flow within a bed could be inferred by sedimentary structures, plant fragments show apparent directionality perpendicular to the flow. the majority of fragments show signs of intense flattening normal to the bedding surface. finer-grained levels in sequences at the kostadinovica section rarely contain solitary stem fragments which are usually seve ral centimetres long. structureless sandstone beds also contain solitary stems and clay chips which appear randomly scattered throughout the whole bed (fig. 6b). the colour of the plant detritus within units a, b and d ranges from dark brown to pale yellow (fig. 8a). in contrast, plant remains within unit c show intensive coalification (fig. 8b) and have a charcoal black streak. aside from the difference in colour and level of carbonification, the mode of distribution of detritus is similar throughout the whole section. morphological details of plant fragments are in most cases poorly preserved which limited their more precise determination. nevertheless, some of the specimens show characteristics of sphenopsids, pteridophylls and lycopsids (see hübers et al., 2014). all the presented plant remains are comparable to the early carboniferous floras of the carnic alps (see van amerom, 1984; van amerom & schönlaub, 1992; van amerom & kabon, 1999, 2000, 2003). sphenopsids are recognized by their arrangement of vascular segments between nodes and internodes of the stems and the majority of samples belong to archeocalamiteans and sphenophylls. among the determinable specimens archeocalamites radiatus (brongniart) stur (fig. 9a, b) has been identified. less frequently, preserved fragments belonging to the sphenophylls are solitary leafless stems of sphenophyllum tenerrimum ettingshausen (fig. 9c, d). abundant filiform foliage type detritus (meyer-berthaud & rowe, 1997) is grouped within the pteridophylls. although these remains are often found throughout the kostadinovica section, their state of preservation is often poor. some of the preserved specimens resemble rhodeopteridium leptofoliatum van amerom (fig. 9e, see van amerom, 1984) or rhodea sp. foliage types (fig. 9f). lycopsids are represented by stems with distinct scale marks such as lepidodendron sp. (fig. 9g, h). 3.5.2. ichnofossils several turbidite beds of the kostadinovica succession contain trace fossils belonging to the single ichnotaxon dictyodora liebeana (geinitz) which show characteristics comparable to other similar occurrences (e.g. benton, 1982; stepanek & geyer, 1989). this is the first record of dictyodora liebeana (geinitz) from the carpatho-balkanides of serbia. previous discoveries are described from the carboniferous of the dinarides in western serbia (veselinović, 1958; kostić et al., 1976). the distribution and mode of appearance of dictyodora liebeana are similar in all four units of the succession and they are located in the fine-grained layers of the turbidite beds, usually several centimetres below the erosive surface of the overlying bed. in total, 10 samples containing larger fragments of the trace fossil were collected from the kostadinovica quarry and studied. several other samples were studied at the quarry. dictyodora liebeana from the kostadinovica section is preserved as segments of the basal burrow, traces in bedding plane view or exposed sections of the mid-dorsal vertical crest (fig. 10). the basal burrow appears as a 7–15 mm wide ridge or furrow with apparent backfill (fig.10b–d). the crest is observed on the bedding plane as meandering, 1–2 mm wide paths which are figure 8. typical mode of occurrence of plant detritus within the lower levels of sandstone intervals of the kostadinovica section. (a) plant detritus from unit d. such a mode of preservation is similar within units a and b. (b) plant detritus from unit c. g eologia c roatica radonjić miloš: hyperpycnites within the devonian-carboniferous flysch of the carpatho-balkanides (kostadinovica, eastern serbia) 137 up to 20 cm long (fig.10a, b). sides of the crest show distinct oblique and longitudinal streaks produced by movement of the animal (fig.10 c, e). longitudinal streaks are spaced on average 0.3–0.5 mm apart, while oblique streaks are arranged in rows 2–4 mm apart and run from the basal burrow upward along the crest. due to intensive fracturing of the rocks, the trace fossil is figure 9. plant fossils from the kostadinovica section. labels in the lower right corners designate their beds within the section (see fig.3). (a) archeocalamites radiatus (brongniart) stur. (b) archeocalamites sp. (c, d) sphenophyllum tenerrimum ettingshausen. e) accumulation of filiform detritus and a specimen similar to rhodeopteridium leptofoliatum van amerom (marked by white arrows). (f ) filiform rhodea sp. type foliage. (g, h) lepidodendron sp. g eo lo gi a c ro at ic a geologia croatica 73/3138 figure 10. various aspects of dictyodora liebeana (geinitz) from the kostadinovica section. arrows point in the direction of the movement of the trace producing animal. labels in the lower right corners designate their beds within the section (see fig. 3). (a) bedding plane view of the trace. (b) view of the basal burrow and the crest. (c) basal burrow and the crest. (d) lower bedding plane view of the basal burrow. (e) axial view of the trace. (f ) polished slab showing axial view of the trace and the location of two thin-sections (fig.10g, h). (h) thin-section showing the position of the traces in laminated siltstones viewed in non-polarized light. (h) thin-section showing plant detritus in fine-grained sediment above d. liebeana viewed in non-polarized light. g eologia c roatica radonjić miloš: hyperpycnites within the devonian-carboniferous flysch of the carpatho-balkanides (kostadinovica, eastern serbia) 139 only partially preserved. some of the paths show intersections, possibly from multiple individuals (fig. 10e). the traces are located in fine-grained layers (fig. 10f). 4. discussion 4.1. the criteria for identification of hyperpycnites and their genetic model the sustained hyperpycnal flows which enter the basin last relatively long if the sediment-laden river discharge is sufficient to maintain the water density difference, usually for several days (mulder & syvitski, 1995). in contrast, remobilization of the sediment by turbidity currents is manifested by brief events (lasting several minutes) that originate on the basin slope due to stability failure of the sediment (mutti et al., 2009). the resulting deposits of both processes reflect their different natures: (1) the hyperpycnites are composed of repetitive sedimentary sequences that contain upward coarsening intervals followed by upward fining intervals and intra-sequence erosional contacts (mulder et al., 2003), all of which is a result of fluctuating river discharge; (2) the turbidites are represented by upward fining bouma sequences (bouma, 1962) originating from a single, sediment-laden turbulent flow. the diagnostic criterion for hyperpycnites is the internal organization of the sedimentary sequence consisting of couplets of inverse and normally graded layers with intersequence erosional surfaces (mulder et al., 2003; yang et al., 2017). given that the kostadinovica section is composed of fine-grained rocks which could be considered to belong to the distal part of the turbidite system (fig. 3., krstić, 1984), the minute variations in grain size and structure would be best observed in thin-section. out of the dozen rock samples collected, only one thin-section (sample from bed d7, fig. 7c) fulfills the diagnostic criterion for hyperpycnites. the similarity of macroscopic sedimentary characteristics of several layers containing plant detritus and bed d7 could be potentially used to indicate their hyperpycnal origin. in addition to sedimentological data, collected fossil material from the site was discussed as an argument for a hyperpycnal mode of transport of the sediment. the siliciclastic succession at kostadinovica shows sedimentary and palaeontological characteristics which could be compared to the model of extrabasinal turbidites (zavala & arcuri, 2016). the observed rocks at the kostadinovica site were grouped into different facies and further discussed following the proposed genetic model of facies for hyperpycnites (fig.11; zafigure 11. the proposed genetic facies model used on the kostadinovica section (modified after zavala & arcuri, 2016). (a) longitudinal changes of characteristics of facies. (b) lateral changes of characteristics of facies. g eo lo gi a c ro at ic a geologia croatica 73/3140 back towards the centre of the system (unit d) (fig. 11b). the alternative interpretation would consider a change in energies of the events within units or at least the combination of both parameters. the vertical organization of facies within the succession is in accordance with expected facies changes (i.e. vertical transition from facies s2 to s3 to s4 and intermediate domains; see fig. 11a). this is best observed within units a and d while in other cases this could be explained by invoking the influence of various deep-marine processes. 4.3. interpretation of the fossil association the most prominent feature of the kostadinovica section is the fossil association of terrestrial vascular plants and the trace fossil dictyodora liebeana (geinitz). these fossils were used to determine the age of the succession and to better constrain its sedimentary setting. remains of vascular plants from the studied section show characteristics which could be compared to mississippian floras of the variscides of central and western europe (hübers et al., 2014). the presented association of sphenophytes, lycophytes and filiform foliage (fig. 9) indicates a viséan to serphukovian age for the kostadinovica succession based on similar material from other european localities, of which some examples are from lower silesia (poland, zimmermann, 1956), doberlug-kirchhain (germany, daber, 1959), giromagny (france, corsin et al., 1973), hochwipfel flysch of the carnic alps (austria and italy, van amerom et al., 1984; van amerom & schölaub, 1992, van amerom & kabon, 1999, 2000, 2003) and the eastern pyrenees (spain, martín-closas et al., 2018). a factor common to the aforementioned occurrences and the kostadinovica section is the transport of the plant material under the turbiditic flow regime. the presented samples from the kostadinovica site are the first discoveries of the early carboniferous flora from serbia. previous palaeobotanical studies attributed the remains of the macroflora from the carpatho-balkanides either to the devonian or late carboniferous exclusively (pantić, 1960; krstić, 2005; see đorđević-milutinović, 2010). another significant palaeontological feature of the kostadinovica section is the trace fossil (fig. 10) dictyodora liebeana (geinitz) which is interpreted as a post-depositional deep-tier pascichnion found in mississippian deep-sea environments (e.g. seilacher, 2007; callow & mcilroy, 2011; uchman & wetzel, 2011). its occurrences are often described from the culm facies, e.g. in thuringia (germany, benton, 1982 and references therein), frankenwald (germany, stpanek & geyer, 1989), menorca (balearic islands, orr, 1994; orr & benton, 1996), moravia and silesia (czech republic, bábek et al., 2004; mikuláš et al., 2002, 2004; kováček & lehotský, 2016; poland, muszer, 2020), carnic alps (austria and italy, baucon & neto de carvalho, 2008). the stratigraphic range of dictyodora liebeana (geinitz) is confined to the early carboniferous (uchman, 2004). one of the arguments for the presence of hyperpycnites within the turbidites deposited in a deep marine environment at the kostadinovica succession is the occurrence of the post-turbidite pascichnion dictyodora liebeana (geinitz) in the upper, fine-grained intervals of the turbidites followed by plant debris accumulations on lamination surfaces within the bottom, coarsegrained levels of the next bed (beds d12 and d13, fig. 12;). the presence of dictyodora liebeana (geinitz) in proximity to vascular plant debris is observed in several intervals of units b, c (bed c3, fig. 10f–h) and d. such distribution of the trace fossils vala & pan, 2018). in the mentioned genetic model (zavala & arcuri, 2016), facies families are related to the main processes governing deposition from the sustained hyperpycnal discharge: (1) deposition of coarse-grained material which is dragged by turbulent flow on the bottom of the current (bedload facies b), (2) deposition of the sediment suspended in the flow during its deceleration (suspended load facies s) and (3) deposition of fine-grained sediment under the density reversal of the hyperpycnal flow when its flow capacity decreases (lofting load facies l). each facies family is further subdivided by its specific characteristics (fig. 11). 4.2. comparison of the kostadinovica section to the proposed genetic model units a and d of the kostadinovica section are characterized by fining-upward sequences which would correspond in most cases to the suspended load facies (s) family and transitional domains of the lofting facies (l) family (fig. 11, zavala & pan, 2018). the sandstone layers within these units mostly represent facies s2l (sandstone with parallel lamination and plant debris), s2h (sandstone with hummocky-type cross lamination) or s3w (sandstone with wavy lamination). the upper, fine-grained part of the beds would correspond to facies s4 (graded siltstones and mudstones) or in some cases the possible background deposition of pelagic sediments. compared to the proposed model (zavala & pan, 2018), the observed vertical association of different facies within units a and d is interpreted as a series of hyperpycnites deposited in a relatively regular order based on the fossil material and sedimentological characteristics. unit b shows the greatest variety of proposed hyperpycnal facies and their irregular transition from one to another. lower levels of the unit comprise mostly of siltstones and mudstones of facies s4. structureless sandstone beds represent solitary events of deposition of facies s1 (massive sandstones). the nature of two prominent beds – b23 and b25, could correspond to the characteristics of facies s1l (massive sandstones with clay chips, silt levels and plant debris) or alternatively facies b3 (pebbly sandstones with diffuse lamination) and reflect events of higher intensity within a relatively calm environment. unit c is predominantly composed of members of the lofting facies family l (laminated sandstones and siltstones with plant debris). the more fine-grained members of the unit are rarely disturbed by thin, structureless sandstone beds of facies s1. the intervals of sandstone beds with irregular wavy lamination represent deposition under a combined flow (facies s3w). according to the proposed model (zavala & pan, 2018), unit c is deposited in conditions of density reversal of a hyperpycnal flow due to its reduction caused by ongoing sedimentation which leads to deposition of fine-grain particles and more buoyant plant debris (gladstone & pritchard, 2010). this lofting process takes place in the marginal parts of the system (outward of the lofting point – lp, fig. 11b). the onset of unit d is marked by a sharp change in facies association compared to unit c. aside from the general similarities described above, differences within units a and d are most notably the rare occurrence of s3 facies (fine-grained sandstones with climbing ripples) within unit d. in terms of the lateral geometry of the proposed system at the kostadinovica section, the change to more fine-grained lithologies should mark the shift away from the central zone of superimposed channel axes towards lobes of the system (from unit a towards unit c), while the opposite shift would mark migration g eologia c roatica radonjić miloš: hyperpycnites within the devonian-carboniferous flysch of the carpatho-balkanides (kostadinovica, eastern serbia) 141 and plants could indicate repetitive hyperpycnal events triggering (or coinciding with) turbiditic transport of the sediment representing several dozen events reflected as distinct sequences (at least within units a and d). 5. conclusions the siliciclastic succession at kostadinovica, as part of the kučaj-zvonce flysch (krstić & maslarević, 1989), is interpreted here as representing the distal part of a turbiditic system with the occasional occurrence of hyperpycnites. the main arguments for the validity of the proposed model are sedimentary characteristics corresponding to the model of extrabasinal turbidites (zavala & pan, 2018) and the concurrent fossil association of in situ deep-marine ichnofossils and debris of vascular plants transported by hyperpycnal currents (zavala et al., 2012). the identification of hyperpycnites by thin-section analyses is only partially achieved and further studies are needed for their more precise discrimination from turbidites. likewise, more detailed study of the petrographic and geochemical provenance of the material would benefit research on a palaeontologically controlled succession as in the one at the kostadinovica site (see kutterolf et al., 2008). based on the discovery of dictyodora liebeana (geinitz) the age of the studied section is established as early carboniferous instead of devonian (krstić, 1984) which is in accordance with the characteristics of the associated mississippian vascular plants (hübers et al., 2014). a more detailed age range could be defined as viséan to middle serpukhovian if compared to the hochwipfel flysch (hubmann et al., 2014). these results could have age implications for similar described occurrences of the kučaj-zvonce flysch of the carpatho-balkanides of serbia (krstić et al., 2004; krstić et al., 2005). palaeontologically controlled successions such as the kostadinovica section offer an important insight into the direct link of continental environments and deep-marine realms. further studi es could provide more information on palaeoenvironmental conditions and sedimentary systems of the studied kučaj-zvonce flysch and similar depositional settings (see sremac, 2012; fan & gong, 2016). contemporaneous equivalent formations within adjacent regions (e.g. the hochwipfel flysch of the carnic alps and the south karavanke, lower carboniferous of the dinarides, sredna gora in bulgaria) could be better compared based on floral elements and their similar sedimentological characteristics. acknowledgement i thank tom van loon and alfred uchman for offering important and helpful comments. ljupko rundić, dejan radivojević, nevenka đerić and hans-jürgen gawlick are gratefully acknowledged for their support and encouragement of this work. references bábek, o., mikuáš, r., zapletal, j. & lehotský, t. (2004): combined tectonic-sediment supply-driven cycles in a lower carboniferous deep-marine foreland basin, moravice formation, czech republic.– int. j. earth sci., 93/2, 241–261. doi: 10.1007/s00531-004-0388-5 baucon, a. & neto de carvalho, c. (2008): from the river to the sea: pramollo, a new ichnolagerstätte from the carnic alps (carboniferous, italy-austria).– acta geol., 83, 87–114. benton, m.j. (1982): dictyodora and associated trace fossils from the paleozoic of thuringia.– lethaia, 15, 115–132. bouma, a.h. (1962): sedimentology of some flysch deposits. a graphic approach to facies interpretation. elsevier, amsterdam, 168 p. callow, r.h.t. & mcilroy, d. (2011): ichnofabrics and ichnofabric-forming trace fossils in phanerozoic turbidites.– bulletin of canadian petroleum geology, 59/2, 103–111. doi: 10.2113/gscpgbull.59.2.103 corsin, p., coulon, m., fourquin, c., paicheler, j.c. & point, r. (1973): etude de la flore de la série de giromagny (viséen supérieur des vosges méridionales). comparaison avec les autres flores du culm des vosges.– bulletin sciences géologiques, 26/1, 43–68. doi: 10.3406/sgeol.1973.1425 daber, r. (1959): die mittel-visé-flora der tiefbohrungen von doberlug-kirchhain.– geologie, 8/26, 1–83. berlin. dimitrijević, m.d. (1997): geology of yugoslavia.– geological institute gemini, special publication, 187 p., belgrade. đorđević-milutinović, d. (2010): an overview of paleozoic and mesozoic sites with macroflora in serbia.– bulletin of the natural history museum, 3, 27–46. belgrade. ebner, f., vozárová, a., kovács, s., kräutner, h., krstić, b., szederkényi, t., jamičić, d., balen, d., belak, m. & trajanova, m. (2008): devonian–carboniferous pre-flysch and flysch environments in the circum pannonian region.– geologica carpathica, 59/2, 159–195. geinitz, h.b. (1867): die organischen überreste im dachschiefer von würzbach bei löbenstein. [the organic leftovers in dachschiefer formation from würzbach bei löbenstein – in german].– nova acta acad. caes. leop. carol., german. natur. curios., 33/3, 1–24. gladstone, c. & pritchard, d. (2010): patterns of deposition from experimental turbidity currents with reversing buoyancy.– sedimentology, 57, 53–84. doi: 10.1111/j.1365-3091.2009.01087.x fan, r.y. & gong, y.m. (2016): ichnological constraints of palaeoenvironmental and palaeoclimatological features of the middle palaeozoic palaeo-asian ocean, evidence from the western junggar, nw china.– palaeogeography, palaeoclimatology, palaeoecology, 459, 209–228. doi: 10.1016/j.palaeo.2016.07.012 hübers, m., bomfleur, b., krings, m., pott, c. & kerp, h. (2014): a reappraisal of mississippian (tournaisian and visean) adpression floras from central and northwestern europe.– zitteliana a, 54, 39–52. doi: 10.5282/ubm/epub.22322 hubmann, b., ebner, f., ferretti, a., kido, e., krainer, k., neubauer, f., schönlaub, h.-p. & suttner, t.j. (2014): the paleozoic era(them), 2nd edition.– in: piller, w.e. [ed.]: the lithostratigraphic units of the austrian stratigraphic chart 2004 (sedimentary successions), vol. i. abhandlungen der geologischen bundesanstalt, 66, 9–133, wien. kostić, v., pešić, l. & filipović, i. (1976): fosilni tragovi („bioglifi“) iz karbonskih tvorevina zapadne srbije i njihov značaj [trace fossils from carboniferous of western serbia and their importance – in serbian with an english summery].– ann. geol. pennins. balk., 40, 127–135. kováček, m. & lehotský, t. (2016): ichnofosilie myslejovického souvrství drahanského kulmu (spodní karbon, moravskoslezská jednotka českého masivu). [trace fossils from the myslejovice formation of the drahany culm basin (lower carboniferous, moravosilesian unit of the bohemian massif) – in chech, with an english abstract].– geologické výzkumy na moravě a ve slezsku v roce 2016, 24–41. kräutner, h.g. & krstić, b. (2002): alpine and pre-alpine structural units within the southern carpathians and the eastern balkanides.– proceedings of xvii congress of carpathian-balkan geological association, bratislava, september 1-4, 2002. geologica carpatica, special issue 53. figure 12. the fossil association as an argument for hyperpycnal influence within the turbiditic succession at kostadinovica. the bed d12 contains dictyodora liebeana (geinitz) (i) in its siltstone interval. the crest is exposed showing its characteristic longitudinal and oblique streaks. the next bed (d13) contains plant debris (p) within the basal sandstone layer with parallel lamination. g eo lo gi a c ro at ic a geologia croatica 73/3142 kräutner, h.g. & krstić, b. (2003): geological map of the carpatho-balkanides between mehadia, oraviţa, niš and sofia.– geoinstitute gemini, belgrade. krstekanić, n., stojadinović, u., kostić, b. & toljić, m. (2017): internal structure of the supragetic unit basement in the serbian carpathians and its significance for the late early cretaceous nappe-stacking.– ann. geol. pennins. balk., 78, 1–15. doi: 10.2298/gabp1778001k krstić, b. (1984): stratigrafija starijeg paleozoika (ordovicijum-devon) između resave i nišave, istočna srbija. [stratigraphy of the lower paleozoic (ordovician-devonian) between rivers resava and nišava – eastern serbia – in serbian, with an english summary].– mémoires du service geologique et geophisique, 22, 1–64. belgrade. krstić, b. & sudar, m. (1989): paleozojski konodonti istočne srbije, jugoslavija i. konodonti franskog kata iz okoline zvonačke banje [paleozoic conodonts of eastern serbia, yugoslavia i. conodonts of frasnian stage from zvonačka banja area – in serbian, with an english abstract].– ann. geol. pennins. balk., 53, 305–318. krstić, b. & maslarević, lj. (1990): depositional environment of the marine palozoic in the hercynid kučaj zone, eastern serbia.– bulletin t. cii de l’académie serbe des sciences et des arts – classe des sciences mathématiques et naturelles, sciences naturelles, 32, 29–37. belgrade. krstić, b., maslarević, lj., ercegovac, m., sudar, m. & đajić, s. (2004): devonian in the carpatho-balkanides of eastern serbia.– bulletin t. cxxviii de l’académie serbe des sciences et des arts – classe des sciences mathématiques et naturelles, sciences naturelles, 42, 7–16. belgrade. krstić, b., filipović, i., maslarević, lj., sudar, m. & ercegovac, m. (2005): carboniferous of the central part of the balkan peninsula.– bulletin t. cxxx de l’académie serbe des sciences et des arts – classe des sciences mathématiques et naturelles, sciences naturelles, 43, 9–28. belgrade. krstić, b., maslarević, lj., sudar, m. & ercegovac, m. (2008): paleozoic and lower triassic formations in the se part of the east serbian carpatho-balkanides.– bulletin t. cxxxv de l’académie serbe des sciences et des arts – classe des sciences mathématiques et naturelles, sciences naturelles, 44, 41–56. belgrade. kutterolf, s., rüdiger, d., schacht, u. & krawinkel, h. (2008): provenance of the carboniferous hochwipfel formation (karawanken mountains, austria/ slovenia) – geochemistry versus petrography.– sedimentary geology, 203, 246–266. doi: 10.1016/j.sedgeo.2007.12.004 martín-closas, c., trias, s. & casas, j.m. (2018): new palaeobotanical data from carboniferous culm deposits constrain the age of the variscan deformation in the eastern pyrenees.– geologica acta, 16/2, 107–123. doi: 10.1344/geologicaacta2018.16.2.1 maslarević, lj. & krstić, b. (1987a): the kučaj-zvonce flysch.– in: dimitrijević, m.n. & dimitrijević, m.d. (eds.): the turbiditic basins of serbia. serbian academy of sciences and arts monographs, 61, 211–237, belgrade. maslarević, lj. & krstić, b. (1987b): paleozojske olistostrome u kučajskozvonačkom flišu jugoslovenskog dela karpato-balkanida [paleozoic olistostromes in the kučaj-zvonce flysch of the yugoslavian carpathio-balkanides – in serbocroatian with an english summery].– geol. vjesnik, 44, 217–232, zagreb. meyer-berthaud, b. & rowe, n.p. (1997): a lower carboniferous plant assemblage from thuringia (germany): compressions.– review of paleobotany and palynology, 97, 361–379. doi: 10.1016/s0034-6667(96)00075-9 mikuláš, r., lehotský, t. & bábek, o. (2002): ichnofabric of the culm facies: a case study of the moravice formation (lower carboniferous; moravia and silesia, czech republic).– geol. carpathica, 53, 141–148. mikuláš, r., lehotský, t. & bábek, o. (2004): trace fossils of the moravice formation from the southern nízký jeseník mts. (lower carboniferous, culm facies; moravia, czech republic).– bulletin of geosciences, 79/2, 81–98. mulder, t. & syvitski, j.p.m. (1995): turbidity currents generated at river mouths during exceptional discharges to the world oceans.– journal of geology, 103, 285–299. doi: 10.1086/629747 mulder, t., syvitski, j.p.m., migeon, s., faugères, j.-c. & savoy, b. (2003): marine hyperpycnal flows: initiation, behavior and related deposits. a review.– marine and petroleum geology, 20, 861–882. doi: 10.1016/j.marpetgeo.2003.01.003 muszer, j. (2020): trace fossils from the mississippian of the piaskowa góra section (the intra-sudetic basin, sw poland).– annales societatis geologorum poloniae, 90, doi: 10.14241/asgp.2020.06 mutti, e., bernoulli, d., ricci lucci, f. & tinterri, r. (2009): turbidites and turbidity currents from alpine ‘flysch’ to the exploration of continental margins.– sedimentology, 56, 267–318. doi: 10.1111/j.1365-3091.2008.01019.x orr, p. (1994): trace fossil tiering within event beds and preservation of frozen profiles: an example from the lower carboniferous of menorca.– palaios, 9/2, 202–210. doi: 10.2307/3515106 orr, p.j. & benton, j.m. (1996): deep marine trace fossil assemblages from the lower carboniferous of menorca, balearic islands, western mediterranean.– geological journal, 1, 235–258. doi: 10.1002/(sici)1099-1034(199609)31:3%3c235::aidgj706%3e3.0.co;2-4 pantić, n. (1960): devonska flora istočne srbije. [devonian flora of eastern serbia – in serbian, with an german abstract].– ann. geol. pennins. balk., 27, 296–315. schmid, m.s., fügenschuh, b., kunov, a., matenco, l., nivergelt, p., oberhänsli, r., pleuger, j., schefer, s., schuster, r., tomljenović, ustaszewski, k. & van hinsbergen, d.j.j. (2020): tectonic units of the alpine collision zone between eastern alps and western turkey.– gondwana research, 78, 308–374. doi: 10.1016/j.gr.2019.07.005 seilacher, a. (2007): trace fossil analysis.– springer-verlag berlin, 236 p. sremac, j. (2012): influence of terrestrial sedimentation in pennsylvanian rocks of croatia.– geologia croatica, 65/3, 273–282. doi: 104154/gc.2012.18 stow, d.a.v. (2005): sedimentary rocks in the field: a colour guide.– manson publishing ltd., london, 205 p. doi: 10.1201/b15204 stpanek, j. & geyer, g. (1989): spurenfossilien aus dem kulm (unterkarbon) des frankenwaldes.– beringeria, 1, 1–55. uchman, a. (2004): phanerozoic history of deep-sea trace fossils.– in: mcilroy, d. (ed.): the application of ichnology to palaeoenvironmental and stratigraphic analysis.– geological society london, special publications, 228, 125–139. doi: 10.1144/ gsl.sp.2004.228.01.07 uchman, a. & wetzel, a. (2011): deep-sea ichnology: the relationships between depositional environment and endobenthic organisms.– in: hüneke, h. & mulder, t. (eds.): deep-sea sediments. developments in sedimentology, 63, 517-556. doi: 10.1016/b978-0-444-53000-4.00008-1 van amerom, h.w.j., flajs, g. & hunger, g. (1984): die “flora der marinellihütte” (mittleres visé) aus dem hochwipfel flysch der karnischen alpen (italien).– mededelingen rijks geologische dienst, 37/3, 21–61, heerlen. van amerom, h.w.j. & schönlaub, h.p. (1992): pflanzenfossilien aus dem karbon von nötsch und der hochwipfel-formation der karnischen alpen (österreich).– jb. geol. b.-a., 135/1, 195–216, wien. van amerom, h.w.j. & kabon, h. (1999): neue fossile floren aus dem nötscher karbon (1. teil).– carinthia ii, 189/109, 637–672, klagenfurt. van amerom, h.w.j. & kabon, h. (2000): neue fossile floren aus dem nötscher karbon (2. teil).– carinthia ii, 190/110, 483–516, klagenfurt. van amerom, h.w.j. & kabon, h. (2000): neue fossile floren aus dem nötscher karbon (3. teil).– carinthia ii, 193/113, 527–560, klagenfurt. veselinović, m. (1958): nov nalazak dictyodora liebeana (weiss) u karbonskim škriljcima zapadne srbije [new find of dictyodora liebeana (weiss) in carboni ferous schists of western serbia – in serbian].– zbornik radova geološkog instituta „jovan žujuović”, 10, 95–97, beograd. veselinović, m., antonijević, i., milošaković, r., mićić, i., krstić, b., čičulić, m., divljan, m. & maslarević, lj. (1964a): osnovna geološka karta sfrj 1:100000. tumač za list boljevac k34-8 [basic geological map of sfry 1:100000, geology of the boljevac sheet – in serbian].– savezni geološki zavod, beograd, 62 p. veselinović, m., antonijević, i., krstić, b., mićić, i., milošaković, r., rakić, b. & banković, v. (1964b): osnovna geološka karta sfrj 1:100000, list boljevac k34-8 [basic geological map of sfry 1:100000, boljevac sheet – in serbian].– savezni geološki zavod, beograd. vozárová, a., ebner, f., kovács, s., kräutner, j.g., szederkenyi, t., krstić, b., sremac, j., aljinović, d., novak, m. & skaberne, d. (2009): late variscan (carboniferous to permian) environments in the circum pannonian region.– geologica carpathica, 60/1, 71–104. doi: 10.2478/v10096-0090002-7 yang, r.c., jin, z.j., van loon, a.j.t., han, z.z. & fan, a.p. (2017): climatic and tectonic controls of lacustrine hyperpycnite origination in the late triassic ordos basin, central china: implications for unconventional petroleum development.– aapg bulletin, 101/1, 95–117. doi: 10.1306/06101615095 zavala, c., arcuri, m. & blanco valiente, l. (2012): the importance of plant remains as a diagnostic criteria for the recognition of ancient hyperpycnites.– revue de paléobiologie, 11, 457–469. zavala, c. & arcuri, m. (2016): intrabasinal and extrabasinal turbidites: origin and distinctive characteristics.– sedimentary geology, 337, 36–54. doi: 10.1016/j.sedgeo.2016.03.008 zavala, c. & pan, s. (2018): hyperpycnal flows and hyperpycnites: origin and distinctive characteristics.– lithologic reservoirs, 30/1, 1–27. doi: 10.3969/j. issn.1673-8926.2018.01.001 zimmermann, f. (1956): paleobotaniczne zapiski z dolno-śląskiego karbonu [notes on the paleobotany of the lower silesian carboniferous – in polish with an english summery].– biull. instytutu geolog., 98, 125–263, warsaw. g eologia c roatica 1. introduction the geological framework is defined by the form and development of the valley structure as well as the lithology and depositional environments within it. structural deformation, volcanism and erosion determine the geometry of the mountains as well as the extent and depth of the valley (hollett et al., 1991). these structures and the lithology strongly control the permeability and storage characteristics of the deposits. the sava river valley is situated in the southwestern (sw) part of the pannonian basin (fig. 1). in its wider area, two principal topographic features represent the surface expression of the the relationship of the geological framework to the quaternary aquifer system in the sava river valley (croatia) željka brkić croatian geological survey, department of hydrogeology and engineering geology, sachsova 2, 10000 zagreb, croatia; (zeljka.brkic@hgi-cgs.hr) doi: 10.4154/gc.2017.12 abstract data from approximately 500 boreholes and an additional 40 wells for which there is a plausible range of data, facilitate description of the geometry of the quaternary aquifer and its characteristics respectively, and pretension of the elements of the conceptual hydrogeological model in the sava river valley. the aquifer heterogeneity is caused by tectonic activity and the depositional environments of the sediments within the valley. in the wider zagreb area, gravel is the dominant component of the aquifer. downstream from zagreb, the aquifer is composed mainly of sand with sporadic intercalations of gravel. an admixture of silt and clay is not uncommon within the sand. the exceptions are alluvial fans that were formed by the right tributaries of the sava river; gravel with sand is dominant in their lithological composition. the best hydrogeological properties of the aquifer system were registered in the vicinity of the sava river, so all large pumping sites are located close to the river. the quaternary aquifer is the main source of the water supply in the sava river valley. geological framework: the mountain ranges and the narrow intermountain valley. mt. medvednica and mt. moslovačka gora as well as the slavonian mountains (mt. papuk, mt. krndija, mt. psunj, mt. požeška and mt. dilj) are situated at the north end of the sava river valley. at the southern end, the valley is bounded by mt. žumberak-samoborsko gorje in croatia as well as mt. prosara, mt. motajica and mt. majevica in bosnia and herzegovina. these mountains were uplifted during the pliocene epoch and quaternary period (pavelić, 2001; šparica et al., 1972a,b; 1983; šparica & buzaljko, 1984; šparica, 1987). the sava river valley is filled with neogene and quaternary sediments. along the southern margin, the maximum depth to article history: manuscript received february 02, 2017 revised manuscript accepted may 05, 2017 available online october 31, 2017 keywords: lithological composition, alluvial fan, quaternary aquifer, hydrogeological characteristics, sava river, croatia figure 1. location of the pan­ nonian basin showing the po­ sition of the sava basin and sava river valley (simplified after horváth, 1993). legend: 1 – mt. medvednica, 2 – mt. mo­ slo va čka gora, 3 – mt. papuk, 4 – mt. krndija, 5 – mt. psunj, 6 – mt. po že ška, 7 – mt. dilj, 8 – mt. žum be račko­samoborsko gorje, 9 – mt. prosara, 10 – mt. mo tajica and 11 – mt. majevica 2017 | 70/3 | 201–213 | 12 figs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society g eo lo gi a c ro at ic a geologia croatica 70/3202 the pre-miocene deposits reaches 4000 m (prelogović, 1975; hernitz, 1983). the older quaternary boundary (lower pleistocene-middle pleistocene) is defined by the conditional e-log marker q’ (urumović et al., 1976). according to urumović et al. (1976), q’ represents the most imposing lithostratigraphic boundary and can be tracked as a regional discontinuity during deposition. above this marker, the coarse-grained sediments, gravel and sand, were deposited, while underlying sediments are silt and clay. the q’ marker lies at a maximum depth of 300 m (hernitz, 1983). the groundwater that accumulates in the sandy and gravelly aquifers above marker q’ is the main source of the water-supply for the whole region. the aim of this paper is to determine the geometry of the quaternary aquifer system in the sava river valley, as well as highlighting its lithological and hydrogeological characteristics. data from approximately 500 boreholes and an additional 40 wells have been collected for the purposes of this research. the boreholes are unevenly distributed in the valley, but most of them are in the wider area of the zagreb aquifer. data from the boreholes were used to update the hydrogeological knowledge of the valley. a series of lithological cross-sections are presented in this study, and new groundwater level data were used to improve the definition of the conceptual hydrogeological model. 2. geological structures of the southwestern part of the pannonian basin the geodynamic evolution of the pannonian basin (pb) has been discussed in many detailed and comprehensive studies (stegena et al., 1975; royden et al., 1983; kázmer & kovács, 1985; royden & horváth, 1988; ratschbacher, 1991; csontos et al., 1992; horvath, 1993; decker & peresson, 1996; peresson & decker, 1997). the southern pb, which extends from eastern slovenia through northern croatia and from northern bosnia to serbia, as well as its evolution, is defigure 2. classification of structures and faults (prelogović et al., 1998). figure 3. cross­section through the sava basin (prelogović et al., 1998). g eologia c roatica brkić željka: the relationship of the geological framework to the quaternary aquifer system in the sava river valley (croatia) 203 scribed by tari & pamić (1998), prelogović et al. (1998), velić (1983). the pb includes the drava river basin in the north and the sava river and slavonija-srijem basins in the south of northern croatia. in this paper, the focus is on the sava river basin. the evolution of the southwestern pannonian basin occurred during continued convergence between the adriatic plate and the southern alps/dinarides. according to prelogović et al. (1998), the most important transcurrent faults that were active in this stress field are the periadriatic fault and its extension in the drava fault and the fault along the margin of the dinarides, which here is referred to as the southern marginal fault of the pb (fig. 2). between these faults, transpression occurred during the pliocene and quaternary. highlighted compressional structures were formed between the sava and the drava faults – the žumberak–medvednica mountains structural unit, the slavonian mountains unit and the moslavačka gora mountains unit. displacement and rotation of the uplifted mountain ranges reduced the area of the surrounding basins. the sava fault zone is illustrated by the transverse crosssection of the sava basin (prelogović et al., 1998). an asymmetric basin was formed during the miocene epoch. several faults within the basin as well as the sw boundary faults were reactivated as reverse faults during compression in the pliocene and quaternary (fig. 3). pavelić (2001) indicated that the evolution of northern croatia and northern bosnia, as a part of the marginal zone of the pannonian basin, is interpreted as resulting from continental rifting. the sava basin, together with the drava basin, požega valley, and the trough along the southern margin of mt. motajica in northern bosnia, form an elongated half-graben due to tectonic subsidence along listric and strike-slip faults. the pliocene epoch and most of the quaternary period represented a new phase of basin evolution characterized by a transition towards overall compression and structural inversion across the entire pb (horváth & cloetingh, 1996). in the north croatian basin, this was marked by the formation of many compressional structures (fig. 4), mostly by inversion of pre-existing listric normal faults and uplift of basement blocks to form the present mountains in the area (e.g., mts. papuk, psunj, požeška, moslavačka, etc.). this period was characterized by strong vertical movements (pavelić, 2001). 3. data and methods borehole and site investigation data were collected from diffe rent sources, but most of them are from the data base of the croatian geological survey as well as from geotechnical and civil engineering companies (eg. geofizika, geotehnika). forty borehole records were selected for construction of lithological profiles throughout the sava river valley. the boreholes that are located along the sava river were used for a longitudinal lithological profile, while a series of boreholes perpendicular to the valley direction was grouped to display cross-sections of the valley. the cross-sections show the lithology present in each borehole and correlations between boreholes. geophysical investigations were also undertaken to define the boundaries, shape and depths of the aquifers. the boundaries of the aquifer layers with different hydraulic conductivity values were identified using pumping test data and grain-size analysis of non-coherent deposits. the lithological composition of the overlying layers is displayed based on soil data for the first 4 m of the overlying layer depth. data were collected from the faculty of agriculture of the university of zagreb (vidaček et al., 2002). 4. results and discussion 4.1. geometry and lithological characteristics of the quaternary aquifer the boundary between the pliocene and pleistocene epochs has not been defined with confidence (bačani et al., 1999). most researchers have concluded that the transition from the pliocene to the pleistocene was gradual. it is believed that climatological, environmental and lithological continuity exists from the pliocene to the pleistocene (magaš, 1986). because of the constant lowering of the sava basin, the type of sedimentation remained the same, mostly from marshes, and the mineral composition changed only partially, suggesting a change in areal distribution (an. šimunić et al., 1973). palaeoclimate conditions in the middle and upper pleistocene played the main role in the transport and deposition of clastic sediments. alternatively, during the warm and humid periods, a large amount of coarse-grained materials was transported by surface waters and deposited in the valleys. in contrast, during the cold and dry periods, fine-grained materials were transported mostly by wind and deposited in the lakes and marshes. the main volume of permeable sediments of which the aquifers are composed was deposited during the middle pleistocene. the vertical and lateral spreading of the aquifers in the sava river valley was caused by neotectonic movements and the formation of the geological structures in the southwestern part of the pannonian basin. the geological and hydrogeological characteristics of the quaternary sediments in the sava river valley are quite diffe rent from those of the drava river valley, where the drava aquifer system is composed of material of mostly the same origin (alps and sporadic surrounding mountains). additionally, in the drava figure 4. model of the evolution of the slavonian mountains and northern bosnia – early quaternary (pavelić, 2001). g eo lo gi a c ro at ic a geologia croatica 70/3204 fi gu re 5 . h yd ro ge ol og ic al p ar am et er s o f t he m ai n al lu vi al a qu ife rs in n or th er n cr oa tia a nd th e ge ne ra l g ro un dw at er fl ow d ire ct io n (m od ifi ed a cc or di ng to b rk ić e t a l., 20 10 , 2 01 3, 2 01 6) . g eologia c roatica brkić željka: the relationship of the geological framework to the quaternary aquifer system in the sava river valley (croatia) 205 river valley, the thickness of the quaternary aquifer gradually increases from west to east as the size of the gravel pebbles and sand grains decreases (babić et al., 1978; urumović et al, 1994). in the late pleistocene and early holocene, tectonic movements were renewed along the edges of the medvednica and žumberak mountains, causing a further lowering of lowland terrain and the formation of the sava river valley in the narrow sense (šikić, 1995). velić & saftić (1996) stated that the sava river broke through from the alps at the beginning of the last warming period (i.e. prior to ~ 10.000 years ago). lowering of the terrain enabled the sava river flow to break through the medvednica-žumberak barrier so that water ran off to the southeast. as the water flow slowed down, it lost energy and began to deposit the fluvial sediments. the coarse-grained sediments were deposited in the wider zagreb area. downstream from zagreb, the prevailing sediments are fineto medium-grained sand, and the major occurrences of the coarse sediments exist only at the mouths of its right tributaries the una, vrbas, ukrina, bosna and drina rivers (brkić & biondić, 2000; capar et al., 1994; urumović & mihelčić, 2000) (fig. 5). in the initial western part of the sava river valley, the quaternary aquifer is very thin (fig. 6). it is composed mainly of gravel with boulders that reach up to 300 mm in size. the aquifer bedrock is composed of marl of miocene age. according to petrographic composition, the origin of the gravel is tied to the alps as well as to mt. samoborsko gorje (part of the mt. žumberak) and mt. medvednica (crnković & bušić, 1970; al. šimunić et al., 1988, velić & saftić, 1991). the size of the gravel pebbles decreases from west to east and from the surface to depth as the proportion of smaller fractions increases. along the edges of the samoborsko gorje hills, there is no gravel from the sava river; in this area, the deposits originated from the bregana, gradna and rakovica streams. the quaternary aquifer reaches a thickness of 54 m in the strmec area (borehole nos-4 on fig. 6). the deposits of the middle pleistocene age were found in the depth interval from 9 to 54 m (velić & saftić, 1991). among the gravel pebbles, there is no limestone; on this basis, it was concluded that the sediments came from the surrounding hills. the sediments were deposited in an isolated local geological structure (borehole nos-4 on fig. 6) that is oriented approximately northeast-southwest. the structure is filled with sediments of middle pleistocene age that in this location have been „spared” from erosion. upstream and downstream of the structure, erosion of these sediments was expressed and manifested by the deposition of the holocene gravel directly onto the miocene sediments. the origin of the holocene gravel is related mainly to the alps. in the area of the geological structure known as „podsusedski prag“, (downstream of borehole nos-4 on fig. 6), where the underground hydraulic connection between samobor and the zagreb basin is limited to a narrow zone barely 1.5 km wide, the aquifer thickness is a maximum of 8 m. east of this structure, the quaternary aquifer thickness increases, reaching a maximum of approximately 100 m in the southeastern part of the zagreb basin (borehole čdp-23 on fig. 6 and fig. 7). downstream of the structure „podsusedski prag”, in the western part of zagreb, deposits of the middle pleistocene have been identified in the depth interval from 10.35 to 24.3 m (velić & durn, 1993). they consist mainly of grey sand with a high proportion of the clay-silt sediments that velić & durn (1993), state were deposited during conditions of rapid sedimentation in an aqueous environment of low energy. downstream from zagreb, at prevlaka and oborovo (borehole os-1 on fig. 6), deposits of the middle pleistocene age occur in the depth interval from 20 to 256 m (sokač, 1978; hernitz et al., 1981). there are several sandy gravel layers within the middle pleistocene deposits. the clay layers are smaller and thinner, and the grain size in the sandy gravel layers decreases figure 6. longitudinal lithological cross­section of the quaternary aquifer through the sava river valley. g eo lo gi a c ro at ic a geologia croatica 70/3206 with depth. from the surface to a depth of 150 m, fine to medium pebbles with a diameter of 10-20 mm dominate, but above 50 m, pebbles can reach a diameter of 80 mm. the sediments of lower pleistocene age were deposited below 256 m. they are represented by layers of clay and finegrained sand. within the clay layers, plant remains were registered. as such, they represent the bedrock of the aquifer system. it should be noted that an. šimunić & bash (1975) and al. šimunić et al. (1988) considered that the middle pleistocene sediments in this area are situated below a depth of 75 m and are figure 8. lateral lithological cross­section of the quaternary aquifer downstream of sisak. figure 7. lateral lithological cross­section of the quaternary aquifer downstream of zagreb. g eologia c roatica brkić željka: the relationship of the geological framework to the quaternary aquifer system in the sava river valley (croatia) 207 overlain by sediments of late pleistocene age. based on the mineralogical and petrographic composition of the upper pleistocene sediments, these authors concluded that most of the detrital material came from mt. medvednica and the neighbouring mountains and a small part from the alps. they also concluded that transport from nearby regions occurred during interstadial periods, while the alpine influence was significant during stadial periods and under the influence of air currents. downstream from dubrovčak (between boreholes os-1 and mpn-1 on fig. 6), the thickness of the aquifer system gradually decreases as it approaches the geological structure known as „sisački prag”. this structure is located along the southern boundary of the sava river valley and the sava fault, along which the lowering of the basin occurred (fig. 3). the aquifer is extremely thin here (borehole zp-7 on fig. 6), reaching only 5 m, and consists of sand with much clay and silt. downstream from sisak, the quaternary aquifer is composed of generally fine to medium-grained sand. the gravel was deposited near the sava river (fig. 8). the maximum thickness of the quaternary aquifer is approximately 100 m in the area of the lonjsko polje (borehole ml1-2 on fig. 6 and pod-2 on fig. 8). the geological structure stružec-osekovo was uplifted between the lonjsko polje and ravnik (fig. 8). below approximately 100-metre thickness of clay-silt sediments, sandy layers occur that could be associated with coarse-grained sediments at both of these locations. between sisak and županja, larger quantities of gravel are related exclusively to the alluvial fans that have been formed by the coarse-grained sediments of the right tributaries of the sava river (the una, vrbas, ukrina and bosna), and to much lesser extent the left tributaries (the ilova, pakra, sloboština, šumetlica and orljava) (figs. 5 and 6). the mineralogical and petrographic composition of sediments in the southern alluvial fans shows that they mostly represent eroded material from the bosnian mountains and that the sediments came partially from alpine distribution areas. due to falling river energy, the coarse-grained material was deposited along the southern edge of the sava and slavonia-srijem basin, while the finer material dominates to the north and is often absent. the layer thickness of the coarse-grained material is quite uneven. the disturbed continuity of the layers is caused by the manner of deposition and by neotectonic movements. the basin evolution during the pliocene and most of the quaternary was characterized by a transition towards overall compression and structural inversion across the entire pannonian basin (horváth & cloetingh, 1996). it resulted in uplift and reverse faulting of the massifs towards the north (jamičić, 1983, 1995; šparica & pamić, 1986; prelogović et al., 1995, 1998; horváth & cloetingh, 1996; tari & pamić, 1998). the reverse faulting was generated by pressure from the south, resulting in an anticlockwise block rotation (jamičić, 1983; márton et al., 1999). in the north croatian basin, this movement resulted in the formation of many compressional structures, mostly by the inversion of pre-existing listric normal faults and uplift of basement blocks to form the present mountains in the area (e.g., papuk, psunj, požeška gora, moslavačka gora, etc.) (pavelić, 2001). during the quaternary, important vertical movements occurred – mt. papuk was uplifted to an elevation of 700 m, and mt. psunj to 750 m (prelogović, 1975). the uplift of the geological structures mt. prosara, mt. motajica and mt. vučjak, as well as the lowered structures between them (where the alluvial fans of the right sava river tributaries were deposited), mark the area of northern bosnia and herzegovina (šparica et al., 1972b; 1983; 1987). tectonic events during the pliocene and quaternary (horváth & cloetingh, 1996; bada et al., 1998) had a major influence on the recent structural pattern of the slavonian mountains (šparica et al., 1987; pavelić, 2001). the same can be said for northern bosnia and herzegovina (šparica et al., 1972b; 1983; 1987). these movements are reflected in the geometry of the quaternary aquifer system in the sava river valley. they are visible in the crosssection through the sava river valley (fig. 6) in which the thickness of the quaternary aquifer is clearly expressed. two upthrown blocks were highlighted in the central part of the sava river valley: near slavonski kobaš (borehole sk-1 at fig. 6) and bebrina, east of slavonski brod (borehole b-8 at fig. 6). the upthrown block near slavonski kobaš is connected with the uplift of mt. motajica, and the upthrown block near bebrina is connected with the uplift of mt. vučjak in bosnia and herzegovina. the aquifer system bedrock was detected at 24.5 m near slavonski kobaš and at 20 m east of slavonski brod. the maximum thickness of the quaternary aquifer was detected in the lowered structures between the upthrown blocks – approximately 100 m in the area of the lonjsko polje (borehole ml1-2 on fig. 6), approximately 70 m in the area of jasenovac (borehole b-8 on fig. 6), approximately 60 m at davor (borehole dz-2 on fig. 6), and over 150 m in the area of migalovci (borehole bm-1 on fig. 6) and slavonski brod (fig. 6). the alluvial aquifer in the fan-shaped area of the vrbas river has a much greater distribution in bosnia and herzegovina (fig. 5). in the wider area of the vrbas river mouth where it meets the sava river in northern bosnia, the sediments of pliocene age were registered at a depth of 256 to 355 m, which means that the lower pleistocene sediments were deposited at a depth of less than 256 m. deposits of the left tributaries of the sava river (except for gravel and sand) often contain a considerable amount of silt and clay. the depth of such deposits in the valley of the sloboština watercourse reaches a few tens of metres (wells b-26 at fig. 9). between the alluvial fan of the right tributaries of the sava river and the left tributaries in the north of the sava river valley, the quaternary aquifer is poorly developed (fig. 5). the permeable sandy layers are relatively rare and thin within semipermeable clay-silt quaternary deposits (fig. 10). they are often found at greater depths. the maximum thickness of the sediments above the conditional marker q’ in eastern slavonia was registered south of đakovo and vinkovci and east of županja. the thickness reaches over 300 m (urumović et al., 1978). the evolutionary history of the structures was observed by comparing the thickness of these sediments with the thicknesses of older formations (prelogović & cvijanović, 1983); these observations show that the thick quaternary sediments were deposited in a local structural depression. the middle pleistocene sediments were detected by palaeontological investigation at a depth of 20 to 165 m (sokač, 1976; urumović & sokač, 1974). west of slavonski brod, the pleistocene deposits were not separated due to a lack of detailed palaeontological documentation. however, according to the number of the coarse-grained layers, which match the deposition in interstadial periods, an. simunic et al. (1973) assumed that the middle pleistocene occurred at depths of 40-120 m. the lower boundary of the middle pleistocene in eastern slavonia is located g eo lo gi a c ro at ic a geologia croatica 70/3208 at a depth between 150 and 200 m (urumović et al., 1978). the bedrock sediments are composed of clay and sand. the layers of the middle pleistocene have separated on the slopes of mt. fruška gora and in the covered areas of the srijem and southern bačka (čičulić-trifunovic & galović, 1983). in the southern bačka, the middle pleistocene sediments were drilled beneath layers of the second danube terrace at a depth of 25 m. they are composed of sand, gravel and lesser amounts of sandy clay. the shallowest aquifer in eastern slavonia consists predominantly of coarse-grained material that was transported by the bosna river (fig. 5). the riss-würm interglacial period was proven by palaeontological investigation of the upper part of the gravelly aquifer close to the sava river (mutić, 1993). the aquifer extends from the sava river in the south to the vrpoljecerna line in the north (miletić et al., 1986), and its depth is approximately 100 m. the diameter of the gravel pebbles reaches 50 mm whereas medium-grained sand is composed of 1-2 mm diameter grains (urumović et al., 1978). in the central and northern parts of the slavonija-srijem depression, the aquifers are composed predominantly of uniform medium-grained sand with particle diameters of 0.1 to 0.3 mm (urumović et al., 1978). within the sand, there are smaller gravel pebbles with a diameter of less than 4 mm. within an approximately 200 m thick succession of sediments, there can be 2 to 11 sand layers (bačani et al., 1999). according to the lithological and well-logging data, six to seven sandy layers could be selected north of županja (boreholes v-1 and v-2 on fig. 6). in the area of đakovo-vinkovci and the vukovar plateau, the hydrogeological conditions are somewhat different. a few sandgravel aquifers were deposited below the thick loess (boreholes b-1 on fig. 11). the thickness of the loess above the aquifer can be greater than 60 m. research conducted on the sediments’ age shows the difficulties in defining the chronostratigraphic divisions. pleistocene figure 10. lateral lithological cross­section of the quaternary aquifer between the sava river and brodski stupnik. figure 9. lateral lithological cross­section of the quaternary aquifer between b.gradiška in bosnia and herzegovina and the slavonian mountains. g eologia c roatica brkić željka: the relationship of the geological framework to the quaternary aquifer system in the sava river valley (croatia) 209 deposits were mostly separated on the basis of palaeontological analysis. according to sokač (1978), the most important forms are a genus of ostracods scottia, ilyocypris and condona, and particular species including scottia tumida, scottia browniana, ilycypris slavonica, condona neglecta, cytherissa lacustris and others. most of these fossils were widespread throughout the whole quaternary, but some were also found in the pliocene. in addition to the palaeontological analysis, a division of the pleistocene is based on climatological characteristics. according to šegota (1963), the pluvial maximum was in the gunz, and the post-gunz phase belongs to the recession phase of the pleistocene glaciation, during which the intensity of pluvials gradually decreased. each glacial period was shorter than the previous one, and šegota concluded that it can be expected that the volume of material accumulated in the riss was higher than in the würm, in the mindel higher than in the riss, etc. the accumulated volume is proportional to the periods’ durations. it has already been stated that deposits at depths greater than 75 m southeast of zagreb have been classified by some authors as middle pleistocene in age (sokač, 1978; hernitz et al., 1981) and by others as representing the upper pleistocene (an. šimunić & bash, 1975; al. šimunić et al., 1988). if the sedimentation occurred as interpreted by šegota (1963), the assumptions about the various stages of würm glaciation southeast of zagreb as interpreted by an. šimunić & bash (1975) and al. šimunić et al. (1988) are questionable. based on the number of gravel layers, these authors believe that the thickness of the upper pleistocene (with the holocene) is approximately 75 metres. they have also stated that layers representing cyclic sedimentation can be observed in the vertical plan. the gravel-sand layers were deposited by the rivers in a warm climate and oxidative conditions (during an interstadial period), while the layers of fine-grained sediments were deposited in the marsh areas in a cold climate and reductive conditions (during a stadial period). however, cyclic sedimentation also occurred during the middle pleistocene. river flow, which was the main transporter of the clastic material, was losing energy, as manifested by the deposition of fine-grained sediments. in this case, it would be more realistic to accept the opinion of sokač (1978) and hernitz et al. (1981), who concluded that the deposits of the upper pleistocene southeast of zagreb are thin and that the upper pleistocene and holocene sediments reach a thickness of barely 20 m. this conclusion was proven by the findings of candona ostracods (candona candida, c. neglecta, c. weltneri, c. marchica) (sokač, 1978). sokač stated that unlike the middle pleistocene deposits, which are rich with forms of scotti, in the upper pleistocene deposits, these fossils are very rare. in other areas of northern croatia, the upper pleistocene sediments, often together with holocene sediments, were observed at a depth of 20-30 m (urumović & sokač, 1974; sokač, 1976; čičulićtrifunović & galović, 1983) and 30-40 m (an. šimunić et al., 1973; babić et al., 1978; urumović et al., 1978). quaternary aquifers are mostly overlain by marshy sediments that were formed during the upper pleistocene and holocene. these overlying deposits above aquifers are semipermeable and, with regard to their hydrogeological function, are considered to be an aquitard. at the extreme west of the sava river valley, the aquitard belongs to flood facies of the sava river and is of holocene age. downstream from sisak, the aquitard belongs to flood facies of the sava river as well as lake-marsh facies of holocene age, below which was deposited in the marsh loess of upper pleistocene age. tectonic movements led to the uplift of the vinkovci area so that the continental loess was partially deposited (galović & mutić, 1984; mutić, 1990). figure 11. lithological cross­section of the quaternary aquifer between županja and vukovar plateau. g eo lo gi a c ro at ic a geologia croatica 70/3210 the aquitard can reach a thickness of more than 50 m. in the uttermost western part of the sava river valley, the aquitard is very thin and is often missing. downstream, its thickness increases and in some places reaches more than 20 m – in eastern slavonia, sometimes even more than 40 m (fig. 12a). generally, an aquitard is composed of clay, silt and fine-grained sand. unlike the aquitard above the drava aquifer, clay is the dominant component in the shallow parts of the covering aquitard in the sava river valley (fig. 12b). this is especially pronounced in the western and central parts of the valleys. 4.2. the sava river valley – a regional groundwater resource in the wider zagreb area, the average hydraulic conductivity of the gravel-sand aquifer is extremely high (fig. 5). west of the geological structure podsusedski prag, the hydraulic conducti vity of the aquifer reaches 3400 m/day. east of zagreb, it decreases to approximately 2000 m/day. near the geological structure sisački prag, sand becomes the dominant material in the composition of the aquifer (fig. 6), and the average hydraulic conducfigure 12. covering aquitard thickness (a) and lithological composition of the upper part of the covering aquitard (b). g eologia c roatica brkić željka: the relationship of the geological framework to the quaternary aquifer system in the sava river valley (croatia) 211 tivity of the aquifer is reduced to less than 50 m/day. within the aquifer, there are several permeable layers that are separated by low-permeability clay-silt layers. these layers in some places are missing, which has caused the formation of a unique hydraulic aquifer with expressed heterogeneity and anisotropy. in the wider zagreb area, the sava riverbed cuts into the aquifer, and the water in the river is hydraulically connected to the groundwater in the aquifer. the groundwater is drained by the sava river during most of the year. in the area of the geological structure podsusedski prag, due to the narrowing of the alluvion, the groundwater flows to the sava river. approximately 10 km downstream from the podsusedski prag, in the central part of the zagreb area, on the right bank, groundwater is recharged by the sava river at lowand high-water levels (fig. 5). the main cause of the groundwater recharge by the sava river in this area is groundwater abstraction at the zagreb pumping sites. downstream from the city of zagreb, the hydraulic image changes, and groundwater flows into the sava river. between zagreb and sisak, discharge of groundwater to the surface is a widespread phenomenon that is especially pronounced during long-term highwater levels. it is caused by the inflow of groundwater in a neotectonic depression where the piezometer levels exist above ground level. groundwater is discharged to the odra, a left tributary of the kupa river. the odra flows between vukomeračke gorice and the sava river. it is recharged by groundwater that flows from vukomeračke gorice and groundwater that flows from the southeastern part of zagreb. downstream from sisak, in the area of the lonjsko polje, the average hydraulic conductivity of the sandy aquifer is approximately 50 m/day. towards the northern and the southern boundaries of the sava river valley, it decreases to less than 10 m/day. in the alluvial fan of the una river, the average hydraulic conductivity of the gravel-sand aquifer reaches 100 m/day; in the alluvial fan of the vrbas river, it is approximately 200 m/day; and in the alluvial fan of the ukrina river, it reaches 170 m/day (fig. 5). the lower values of the average hydraulic conductivity can be found at the northernmost edge of the aquifer as a result of smaller particle size and higher content of finer sediments. deeper aquifers, which lie at depths greater than 60 m (figs. 9 and 10), also have lower values of their hydrogeological parameters. the maximum of their average hydraulic conductivity reaches 10 m/day. the average hydraulic conductivity of the gravel-sand aquifer that belongs to the alluvial fan of the bosna river reaches 170 m/day (fig. 5). the average hydraulic conductivity of the sandy aquifer in the central and northern parts of the slavonia-srijem basin varies from 4 to 13 m/day in the deeper aquifers to approximately 30 m/day in the shallow aquifer. downstream from sisak, measurements of the groundwater level have not been established. occasional measurements of the groundwater levels at several locations in the lonjsko polje area and eastern slavonia show that groundwater flows towards the sava river during most of the year (brkić et al., 2013; 2016) (fig. 5). recharge from the river occurs during the high water levels and lasts a relatively short time. the main source of the aquifer recharge is the infiltration of precipitation through the covering aquitard, while draining of the aquifer is caused by evapotranspiration and groundwater discharge to the watercourses. the bosut river in eastern slavonia was formed much like the odra river in the western part of the sava river valley. the sava river flows through hypsometrically higher terrain in relation to its hinterland. due to the thinness of the covering aquitard in some places along the sava river, the riverbed cuts into the aquifer, thus achieving direct communication between the river and groundwater (brkić et al., 2016). the piezometer level is held by the sava water stage. it can be higher than the terrain in the hinterland, especially during very high waters. the berava stream has formed by the groundwater discharge to the surface. its extension the bosut river still flows on the aquitard, and direct contact with groundwater is significantly weakened. in the area of the đakovo-vinkovci plateau, below a 20-30 m thick loess deposit, the sandy aquifer is registered. the aquifer transmissivity, according to existing data, reaches 150 m2/day. the relatively thick sand aquifer with transmissivity of 300-400 m2/day was drilled in the vinkovci area. good hydrogeological properties of the aquifer at the vukovar plateau were determined in the area from čakovci to mikluševci (figs. 5 and 11). based on the test pumping wells in čakovci and mikluševci, the aquifer transmissivity was determined to be of 360 and 550 m2/day, respectively. artesian aquifers were registered in the lowlands of the đakovo area and are a result of the position of the piezometric levels. 5. conclusion two principal topographic features of the study area represent the surface expression of the geological framework – the mountains on the north and south sides of the valley and the narrow valley between them. the mountains consist of sedimentary, magmatic, and metamorphic rocks. the valley is filled with unconsolidated to moderately consolidated deposits. these sediments are mostly material that was eroded from the surrounding bedrock mountains and mountains in the catchment area of the sava river. nearly all important drinking groundwater that comes from this area is transmitted and stored in the youngest sediments of the valley fill, which are from the quaternary age. the bedrock that surrounds and underlies the valley fill is apparently impermeable. the structural configuration of the aquifer system bedrock beneath the sava river valley outlines the extent and depth of the valley fill and therefore affects the movement and storage of groundwater. the aquifer system bedrock beneath the valley is a narrow basin, divided into several inter-connected structural basins. it is important to highlight the existence of a series of uplifted and lowered geological structures that are the results of the compression of the basin area. faults extend along the geological structures. the sedimentary depositional systems were formed between two upthrown blocks, podsusedski and sisački prag. downstream from sisak, two upthrown blocks were highlighted: near slavonski kobaš and bebrina, and east of slavonski brod. podsusedski prag is connected with the uplift of the žumberakmedvednica structural unit. sisački prag is situated along the southern boundary of the sava river basin. the upthrown block near slavonski kobaš is connected with the uplift of mt. motajica, and the upthrown block near bebrina is connected with the uplift of mt. vučjak in bosnia and herzegovina. the deepest part of the quaternary aquifer system bedrock was detected between zagreb and sisak, and is more than 200 m below the land surface. east of slavonski brod in slavonia, it was also registered at a depth of 200 m below the land surface. between these lowered structures, the aquifer system bedrock was detected at much lower depths – 8 m at the sisački prag, 24.5 m g eo lo gi a c ro at ic a geologia croatica 70/3212 near slavonski kobaš and 20 m east of slavonski brod. the aquifer system bedrock was registered at a maximum depth of 100 m below the land surface in the lonjsko polje between sisak and slavonski kobaš. the quaternary aquifer system is mostly composed of alluvial sediments from the sava river and watercourses existing before the occurrence of the sava river in the western part of the valley as well as of alluvial sediments that were transported by the right tributaries of the sava river and which belong to the alluvial fans in the eastern part of the valley. the best hydrogeological properties of the aquifer system were registered in the vicinity of the sava river, so all large pumping sites are located close to the river. in many places, the sava riverbed cuts into the aquifer, and induced inflow from the river can be enabled. the groundwater flow direction is from the valley margins towards the sava river. the main source of groundwater recharge is infiltration of precipitation. groundwater discharge occurs primarily through the sava river and evapotranspiration and, to a much lesser extent, through pumping. such conceptualization of the aquifer system can serve as the physical and hydraulic basis for a future numerical evaluation of the regional hydrogeological system. acknowledgement the research was conducted within the project „basic hydrogeological map of the republic of croatia“ which was financed by the ministry of science, education and sports, republic of croatia. the author is grateful to the editor and reviewers for the careful review of the article. their useful comments and suggestions have helped to improve the manuscript. references babić, ž., čakarun, i., sokač, a. & mraz, v. (1978): o geologiji kvartarnih naslaga porječja rijeke drave [about the geology of quaternary deposits of the drava river basin – in croatian].– geol. vjesnik, 30/1, 43–61. bačani, a. šparica, m. & velić, j. (1999): quaternary deposits as the hydrogeological system of eastern slavonia.– geol. croat., 52/2, 141–152. doi: 10.4154/ gc.1999.12 bada, g., cloetingh, s., gerner, p. & horváth, f. (1998): sources of recent tectonic stress in the pannonian region: inferences from finite element modelling.– geophys. int., 134, 87–101. brkić, ž., briški, m. & marković, t. (2016): use of hydrochemistry and isotopes for improving the knowledge of groundwater flow in a semiconfined aquifer system of the eastern slavonia (croatia).– catena, 142, 153–165. doi: 10.1016/j.catena.2016.03.010 brkić, ž., urumović, k. & briški, m. (2013): post audit analysis of a groundwater level prediction model in developed semiconfined aquifer system.– water resour. manag., 27/9, 3349–3363. doi: 10.1007/s11269-013-0351-y brkić, ž., larva, o. & urumović, k. (2010): quantity status of groundwater in alluvial aquifers in northern croatia.– geol. croat., 63/3, 283–298. doi: 10.4154/ gc.2010.23 brkić, ž. & biondić, b. (2000): savski vodonosnik i njegove hidrogeološke značajke. [sava aquifer and its hydrogeological characteristics – in croatian].– zbornik radova, okrugli stol: hidrologija i vodni resursi save u novim uvjetima, slavonski brod, 217–228. capar, a., bačani, a. & miletić, p. (1994): hidrogeološka obilježja porječja save od dugog sela do slavonskog broda [hydrogeological characteristics of the sava catchment area from dugo selo to slavonski brod – in croatian].– hrvatske vode, 2/6, 375–386. crnković, b. & bušić, m. (1970): mineraloško-petrografski sastav nanosa rijeke save [mineralogical and petrological composition of the sava river sediment – in croatian].– zbornik radova rgn fak. sveuč. u povodu 30 g. rada (1939–1969), 133–140. csontos, l., nagymarosy, a., horváth, f. & kovács, m. (1992): tertiary evolution of the intra-carpathian area: a model.– tectonophysics, 208, 221–241. doi: 10.1016/0040-1951(92)90346-8 čičulić-trifunović, m. & galović, i. (1983): osnovna geološka karta sfrj 1:100 000. tumač za list bačka palanka l34–99 [basic geological map of sfry 1:100000, geology of the bačka palanka sheet – in croatian].– geološki institut beograd i geološki zavod zagreb, savezni geološki zavod, beograd, 46 p. decker, k. & peresson, h. (1996): tertiary kinematics in the alpine-carpathianpannonian system: links between thrusting, transform faulting and crustal extension.– in: wassely, g. & liebl, w. (eds): oil and gas in alpidic thrustbelts and basins of central and eastern europe. eage spec. publ., 5, 69–77. galović, i. & mutić, r. (1984): gornjopleistocenski sedimenti istočne slavonije (hrvatska) [upper pleistocene sediments of eastern slavonia (croatia) – in croatian].– rad jugosl. akad. znan. umjet., 411 (razr. prir. znan., 20), 299–356, zagreb. hernitz, z. (1983): dubinski strukturno-tektonski odnosi u području istočne slavonije. [deep structural-tectonic relations in the area of eastern slavonia – in croatian].– phd thesis, jugosl. komitet svjet. kongr. za naftu, nafta, 221 p. hernitz, z., kovačević, s., velić, j., željko, b. & urli, m. (1981): primjer kompleksnih geološko-geofizičkih istraživanja kvartarnih naslaga u oklici prevlake [example of the complex geological-geophysical studies of the quaternary deposits around prevlaka – in croatian].– geol. vjesnik, 33, 11–34. hollett, k.j., danskin, w.r., mccaffrey, w.f. & walti, c.l. (1991): geology and water resources of owens valley, california.– usgs water-supply paper 2370-b. horváth, f. (1993): towards a mechanical model for the formation of the pannnonian basin.– tectonophysics, 226, 333–357. horváth, f. & cloetingh, s. (1996): stress-induced late stage subsidence anomalies in the pannonian basin.– tectonophysics, 266, 287–300. doi: 10.1016/ s0040-1951(96)00194-1 jamičić, d. (1983): strukturni sklop metamorfnih stijena krndije i južnih padina papuka [structural fabric of the metamorphosed rocks of mt. krndija and the eastern part of mt. papuk – in croatian].– geol. vjesnik, 36, 51–72. jamičić, d. (1995): the role of sinistral strike-slip faults in the formation of the structural fabric of the slavonian mts. (eastern croatia).– geol. croatica, 48/2, 155– 160. doi: 10.4154/gc.1995.12 kázmer, m. & kovács, s. (1985): permian-paleogene paleogeography along the eastern part of the insubric-periadriatic lineament system: evidence for continental escape of the bakony-drauzug.– acta geol. hung., 28, 71–84. magaš, n. (1986): osnovna geološka karta sfrj 1:100 000. tumač za list osijek l34–86. [basic geological map of sfry 1:100000, geology of the osijek sheet – in croatian].– geološki zavod zagreb, savezni geološki zavod, beograd, 54 p. márton, e., pavelić, d., tomljenović, b., pamić, j. & márton, p. (1999): first paleomagnetic results on tertiary rocks from the slavonian mountains in the southern pannonian basin, croatia.– geol. carpathica, 50, 273–279. miletić, p., bačani, a., mayer, d. & capar, a. (1986): prilog poznavanju hidrogeoloških značajki prve hidrogeološke zone na području istočne slavonije [contribution to the knowing of the hydrogeological characteristics of the first hydrogeological zone in eastern slavonia – in croatian].– geol. vjesnik, 39, 137– 150. mutić, r: (1990): korelacija kvartara istočne slavonije na osnovi podataka mine raloško-petrografskih analiza (istočna hrvatska, jugoslavija). dio ii: lesni ravnjak [correlation of the quaternary sediments in the eastern slavonia on the basis of mineralogical and petrographic data (eastern croatia, yugoslavia). part ii: loess plateau – in croatian].– acta geol., 20/2, 29–80, zagreb. mutić, r: (1993): korelacija kvartara istočne slavonije na osnovi podataka mineraloško-petrografskih analiza (istočna hrvatska, jugoslavija). dio iii: slavoniasrijem basin [correlation of the quaternary sediments in the eastern slavonia on the basis of mineralogical and petrographic data (eastern croatia, yugoslavia). part iii: slavonsko – in croatian].– acta geol., 23/1, 1–37, zagreb. pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.– basin research, 12, 359– 376. doi: 10.1046/j.0950-091x.2001.00155.x peresson, h. & decker, k. (1997): far-field effects of late miocene subduction in the eastern carpathians: e-w compression and inversion of structures in the alpinecarpathian-pannonian region.– tectonics, 16/1, 38–56. doi: 10.1029/96tc02730 prelogović, e. (1975): neotektonska karta sr hrvatske [neotectonic map of the sr hrvatska – in croatian].– geol. vjesnik, 28, 97–108. prelogović, e. & cvijanović, d. (1983): prikaz neotektonske aktivnosti dijela slavonije, baranje i bačke [neotectonic activity of a part of slavonia, baranja and bačka – in croatian].– geol. vjesnik, 36, 241–254, zagreb. prelogović, e., jamičić, d., aljinović, b., saftić, b. & velić, j. (1995): dinamika nastanka struktura južnog dijela panonskog bazena [the dynamics of the formation of structures of the southern part of the pannonian basin – in croatian].– in: vlahović, i., velić i. & šparica, m. (eds): 1. hrvatski geološki kongres, zbornik radova, 481–486. prelogović, e., saftić, b., kuk, v., velić, j., dragaš, m. & lučić, d. (1998): tectonic activity in the croatian part of the pannonian basin.– tectonophysics, 297, 283–293. doi: 10.1016/s0040-1951(98)00173-5 g eologia c roatica brkić željka: the relationship of the geological framework to the quaternary aquifer system in the sava river valley (croatia) 213 ratschbacher, l. (1991): lateral extrusion in the eastern alps, part i. boundary conditions and experiments scaled for gravity.– tectonics, 10, 245–256. doi: 10.1029/90tc02622 royden, l., horváth, f. & rumpler, j. (1983): evolution of the pannonian basin system. 1. tectonics.– tectonics, 2/1, 63–90. doi: 10.1029/tc002i001p00063 royden, l.h. & horváth, f. (eds.) (1988): the panonian basin. a study in basin evolution.– am. assoc. pet. geol. mem., 45. sokač, a. (1978): pleistocene ostracode fauna of the panonian basin in croatia.– paleont. jugosl., 20, 1–51. sokač, a. (1976): pleistocenska fauna ostrakoda iz nekih bušotina u istočnoj slavoniji (sjeverna hrvatska) [the pleistocene fauna of ostracoda from some wells in eastern slavonia (northern croatia) – in croatian].– geol. vjesnik, 29, 159–172. stegena, j., geczy, b. & horváth, f. (1975): late cenozoik evolution of the pannonian basin.– tectonophysics, 26, 71–90. šegota, t. (1963): geografske osnove glacijala [geographical base of the glacial – in croatian].– radovi geograf. instituta, 4, 1–119. šikić, k. (1995): prikaz geološke građe medvednice [overview of geolocical structure of the medvednica mt. – in croatian].– in: šikić, k. (ed.): geološki vodič medved nice, 7–40. šimunić, al., novosel-škorić, s. & piljurović, lj. (1988): litološka korelacija i kronostratigrafsko razgraničavanje kvartarnih naslaga na lokalitetu prevlaka jugoistočno od zagreba [lithological correlation and chronostratigraphic delimitation of quaternary sediments at the location prevlaka southeast of zagreb – in croatian].– geol. vjesnik, 41, 167–179. šimunić, an. & basch, o. (1975): stratigrafija kvartarnih sedimenata zagrebačkog posavlja [the stratigraphy of quaternary sediments in the zagrebačko posavlje – in croatian].– geol. vjesnik, 28, 153–164. šimunić, an., šparica, m. & šimunić, al. (1973): kvartarne naslage na području slavonski brod-staro petrovo selo [quaternary sediments in the area of slavonski brod – staro petrovo selo – in croatian].– geol. vjesnik, 26, 73–82. šparica, m. (1987): osnovna geološka karta sfrj 1:100.000. list slavonski brod l34-97. – geol. zavod zagreb & geoinženjering sarajevo (1986), sav. geol. za– geol. zavod zagreb & geoinženjering sarajevo (1986), sav. geol. zageol. zavod zagreb & geoinženjering sarajevo (1986), sav. geol. zavod, beograd. šparica, m., buzaljko, r. & pavelić, d. (1987): osnovna geološka karta sfrj 1:100.000. tumač za list slavonski brod l34-97.– geol. zavod zagreb & geoinženjering sarajevo (1986), sav. geol. zavod, beograd, 56 p. šparica, m. & pamić, j. (1986): prilog poznavanju tektonike požeške gore. [contribution to the knowing of the požeška gora tectonic – in croatian].– rad jazu, 21, 85–96. šparica, m., buzaljko, r. & jovanović, č. (1983): osnovna geološka karta sfrj 1:100.000. list nova gradiška l33–107.– geol. zavod zagreb & geoinženjering sarajevo (1983), sav. geol. zavod, beograd. šparica, m. & buzaljko, r. (1984): osnovna geološka karta sfrj 1:100.000. tumač za list nova gradiška l33–107.– geol. zavod zagreb & geoinženjering sarajevo (1983), sav. geol. zavod, beograd, 54 p. šparica, m., juriša, m., crnko, j., šimunić, a., jovanović, č. & živanović, d. (1972a): osnovna geološka karta sfrj 1:100.000. list nova kapela l33–108.– geol. zavod zagreb & institut za geologiju sarajevo (1972), sav. geol. zavod, beograd. šparica, m., juriša, m., crnko, j., šimunić, a., jovanović, č. & živanović, d. (1972b): osnovna geološka karta sfrj 1:100.000. tumač za list nova kapela l33–108.– geol. zavod zagreb & institut za geologiju sarajevo (1972), sav. geol. zavod, beograd, 55 p. tari, v. & pamić, j. (1998): geodynamic evolution of the northern dinarides and the southern part of the pannonian basin.– tectonophysics, 297, 269–281. doi: 10.1016/s0040-1951(98)00172-3 urumović, k. & mihelčić, d. (2000): podzemne vode savskog vodonosnika. [groundwater of the sava aquifer – in croatian].– zbornik radova, okrugli stol: hidrologija i vodni resursi save u novim uvjetima, slavonski brod, 205–215. urumović, k., hlevnjak, b., tadić, z. & petrović, m. (1994): zalihe podzemnih voda dravskog kvartarnog vodonosnika i mogućnosti korištenja [groundwater resources of the quaternary aquifer in the drava river valley and possibility of exploitation – in croatian].– priopćenja sa znan.skupa: „poljoprivreda i gospodarenje vodama“, bizovačke toplice, 425–433. urumović, k., hernitz, z. & šimon, j. (1978): o kvartarnim naslagama istočne posavine [about quaternary sediments of eastern posavina – in croatian].– geol. vjesnik, 30/1, 297–308. urumović, k., hernitz, z., šimon, j. & i velić, j. (1976): o propusnom mediju kvartarnih, te gornjo i srednjepliocenskih naslaga sjeverne hrvatske [about permeable medium of the quaternary, upper and middle pliocen’s deposits in the northern croatian – in croatian].– zbornik radova 4. jug. simp. o hidrogeol. i inž. geol., knjiga 2, 395–410. urumović, k. & sokač, a. (1974): o kvartarnim naslagama županje [about quaternary sediments of županja – in croatian].– geol. vjesnik, 27, 319–330. velić, j. (1983): the neotectonic relations and development of the western part of the sava river depression (in croatian).– acta geol. jugosl. akad. znan. umjet., 13/2, 26–65. velić, j. & saftić, b. (1996): dubinskogeološki odnosi područja smetlišta „jakuševec” – čimbenik sanacije [subsurface geological relations in the area of „jakuševec” dump – a solving factor – in croatian].– proceedings of the ivth international symposium „waste management – zagreb ’96”, zagreb, 197–205. velić, j. & durn, g. (1993): alternating lacustrine-marsh sedimentation and subaerial exposure phases during quaternary: prečko, zagreb, croatia.– geol. croatica, 46/1, 71–90. doi: 10.4154/gc.1993.06 velić, j. & saftić, b. (1991): potpovršinska rasprostranjenost i facijesne značajke srednjopleistocenskih taložina u području između zaprešića i samobora.– geol. vjesnik, 44, 78–82. vidaček, ž., bogunović, m., husnjak, s., sraka, m., bensa, a. & petošić, d. (2002): hidropedološka karta republike hrvatske 1:300.000. vodno područje sliva save [hydropedological map of the republic of croatia, sava river basin – in croatian]. g eo lo gi a c ro at ic a geologia croatica 70/3214 www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2025 | 78/3 | 205–220 | 9 figs. | 4 tabs. | 1 suppl. | article history: manuscript received: january 15, 2025 revised manuscript accepted: july 15, 2025 available online: october 13, 2025 keywords: mollusca, foraminifera, ostracoda, fossil assemblages, palaeoecology, community responses, human impact 1. introduction 1.1. combining conservation and stratigraphic palaeobiology conservation palaeobiology aims to expand the temporal perspective of conservation science by integrating ecology and palaeobiology to protect ecosystems and enhance biodiversity and to evaluate ecological responses to both human activities and natural environmental changes (jackson, 2001; willis & birks, 2006; jackson & hobbs, 2009; dietl & flessa, 2011). the differences between recent benthic communities and palaeoecological baselines observed in the pleistocene and holocene fossil records can be used to assess the magnitude and timing of human impacts on populations, communities and ecosystems (dietl & flessa, 2011). the interdisciplinary nature of conservation palaeobiology provides a comprehensive approach to understand ecosystem changes by incorporating palaeobiological, archaeological, and histor late holocene changes in the composition of foraminiferal, ostracod and molluscan communities in condensed sediments (northern adriatic sea) michaela berensmeier1,*, adam tomašových2, rafał nawrot1, vlasta ćosović3, eva hasenzagel1, petra heinz1, martin zuschin1 1 university of vienna, institute for palaeontology, josef-holaubek-platz 2 (uza ii), 1090 vienna, austria; (*corresponding author: michaela.berensmeier@univie.ac.at; rafal.nawrot@univie.ac.at; eva.hasenzagel@gmx.at; petra.heinz@univie.ac.at; martin.zuschin@univie.ac.at) 2 slovak academy of sciences, earth science institute, dubravska cesta 9, bratislava, 84005, slovakia; (adam.tomasovych@savba.sk) 3 university of zagreb, faculty of science, department of geology, horvatovac 102b, 10000 zagreb, croatia; (vcosovic@geol.pmf.hr) doi: 10.4154/gc.2025.16 abstract human-induced changes in sedimentation rates, pollution, and eutrophication significantly transformed the benthic communities in the northern adriatic sea during the late holocene, particularly in recent centuries. fossil assemblages from sediment cores record these changes but are often affected by stratigraphic condensation and mixing. here, we show that molluscan, foraminiferal, and ostracod assemblages preserved in a condensed sediment core collected off the po delta at 31 m water depth, still archive information about the composition of benthic communities prior to anthropogenic changes. all three groups exhibit a similar trend in total abundance (density): a gradual increase peaking in a 10 cm-thick shelly lag (≈ 2 – 6 kyr bp) with millennial time-averaging, followed by a significant decline in the uppermost 5 cm of highstand silts (representing the past 2 kyr bp) with centennial time-averaging. the molluscan assemblage in the shelly lag integrates across several baseline community states. the assemblage mainly comprises shallow-subtidal filter feeders and soft-bottom infauna, with the bivalve varicorbula gibba and the gastropod turritellinella tricarinata dominating and increasing in proportional abundance in the highstand silts. the ostracod and benthic foraminiferal assemblages in the shelly lag are dominated by opportunistic species such as cytheridea neapolitana, ammonia beccarii, and haynesina germanica. in contrast, the foraminifera nonionella sp. and the ostracod loxoconcha sp. increase in proportional abundance in the highstand silts, characterised by an increase in filter-feeders among the molluscs, infaunalisation and a decrease in epiphytic species. although an increase in net sediment accumulation primarily causes the decline in fossil density in the uppermost part of the core, upward changes in the relative abundance of species and functional groups reveal a difference between the baseline and impacted community states. therefore, the time-averaged fossil assemblage in the shelly lag provides a valuable long-term record of an ecosystem in the region before human impact. ical data. even the youngest fossil records can be affected by biases due to the variable completeness and resolution of fossil assemblages (e.g., scarponi et al., 2017; tomašových et al., 2023; nawrot et al., 2024; zecchin et al., 2024). these biases can impact our understanding of temporal population and community dynamics (ager, 1973; patzkowsky & holland, 2012). stratigraphic palaeobiology is a subdiscipline of palaeobiology that examines spatial and temporal patterns of fossil distribution in a stratigraphic context. this approach explicitly recognises that both biological processes, such as speciation, extinction, and community assembly, as well as stratigraphic processes, including sedimentation, erosion, and condensation, impact the fossil record (dresow, 2023). consequently, the integration of conservation palaeobiology with the toolkit used by stratigraphic palaeobiology can provide more rigorous reconstructions of the recent geological past and increase the reliability of the data on the longterm history of human impact on ecosystems. g eo lo gi a c ro at ic a 206 geologia croatica 78/3 1.2. stressors in the northern adriatic the northern adriatic sea is a dynamic and diverse ecosystem that has experienced significant changes due to the combined effects of natural processes and human activities over the past millennia. this has led to considerable alterations in the composition of marine communities, making it one of the most disturbed continental shelves on earth (lotze et al., 2011; gallmetzer et al., 2019; haselmair et al., 2021; scarponi et al., 2022) (see table 1). it is essential to analyse fossil assemblages to understand the long-term effects on local ecosystems, as systematic ecological monitoring only began in the 20th century. data from the holocene fossil record show that the faunal composition in the northern adriatic has changed significantly over the past millennia and centuries (e.g., tomašových et al., 2017, 2018; gallmetzer et al., 2019; scarponi et al., 2022). while some species have drastically decreased in abundance, a few opportunistic species survived and proliferated (gallmetzer et al., 2017; haselmair et al., 2021). however, most studies that have examined holocene changes in the composition of benthic assemblages within sediment cores have focused on single taxonomic groups, such as macrofauna (e.g., molluscs) (scarponi et al., 2017; gallmetzer et al., 2017; mautner et al., 2018) or microfauna (e.g., foraminifera or ostracods) (barmawidjaja et al., 1995; vidović et al., 2016; picone et al., 2008). for instance, benthic foraminifera in the sediments of the po delta have recorded increased eutrophication and a decline in oxygen availability, which are linked to anthropogenic changes in the po outflow (barmawidjaja et al., 1995). comprehensive quantitative studies that assess the abundance and diversity of multiple phyla simultaneously remain rare (see, e.g., d’amico et al., 2013; rossi et al., 2021; azzarone et al., 2020). furthermore, few multi-taxon studies connect biotic signals to sediment parameters such as grainsizes or organic matter content (barbieri et al., 2019, 2021). 1.3. objectives of the present study quaternary sequences provide a significant advantage for studying palaeoecological patterns within a sequence stratigraphic framework. the assemblages primarily consist of extant taxa with well-documented ecological, biogeographic, and phylogenetic relationships. this palaeoecological data can be compared with assemblage states observed in modern environments, offering insights into how human impacts affect the functioning of contemporary ecosystems. in this study, we take a comprehensive approach to examine holocene changes (over the past ≈ 10,000 years) in the composition of assemblages formed by three different phyla, all within the context of the sequence stratigraphic framework, at a site located in the central part of the northern adriatic sea. this method, which combines conservation and stratigraphic palaeobiology, has been successfully applied at other holocene locations in the northern adriatic sea (e.g., wittmer et al., 2014; gallmetzer et al., 2019; barbieri et al., 2019). however, none of the previous studies directly compared responses of macroand microfaunal assemblages to natural and human-induced environment changes. berensmeier et al. (2023) described the geochronology, geochemistry, and molluscan assemblages at this coring location. despite intensive stratigraphic condensation and mixing of the fossil record at this site, the assemblages and sediments enriched in metals and organic carbon in the uppermost core increments reveal evidence of human impacts. furthermore, the core-chronological data from this study, based on molluscs, was used in a palaeoecological study of core data from the northern adriatic by tomašových et al. (2024). they found that species diversity in fossil assemblages increases with the time averaging of samples, which is influenced by varying sediment accumulation. the main objectives of the present study are to: (i) describe the faunal composition of molluscan, benthic foraminiferal, and ostracod fossil assemblages; (ii) analyse their diversity and species composition within the stratigraphic context; and (iii) assess whether the three types of assemblages respond differently to human impacts. 2. materials and methods 2.1. sampling locality and stratigraphic framework in june 2017, the team of f. s. poseidon-cruise no. 514 took the gravity core pos514-gc25-5 in the western part of the northern adriatic sea, ≈ 32 km to the east of the po delta pila table 1. selected stressors impacting the benthic ecosystem in the northern adriatic. stressor causes (simplified) impact on the benthic ecosystem references (selection) hypoxia and anoxia human-induced eutrophication in combination with ocean stratification mass mortalities; alteration of sediment biogeochemistry; alteration of faunal composition stachowitsch, 1984; justić, 1991; stachowitsch, 2014 mucilage aggregates diatom-blooms after human-induced eutrophication anoxia; mass mortalities stachowitsch et al., 1990; devescovi & iveša, 2007; kraus & ivošević denardis, 2023 chemical pollution human-induced influx of heavy metals, organic pollutants or other alteration of faunal composition; mass mortalities molluscs: gallmetzer et al., 2017; schnedl et al., 2018 benthic foraminifera: frontalini & coccioni, 2011; melis et al., 2019 ostracods: bergin et al., 2006 alien species shipping, aquaculture activities, or a natural range expansion competitive interactions with native species; alteration of the faunal composition; parasitism orlando-bonaca, 2010; occhipinti-ambrogi et al., 2010; crocetta, 2011 bottom trawling still used fishing technique alteration of faunal composition; decrease in faunal densities; habitat loss kollmann & stachowitsch, 2008; pitcher et al., 2022 heat waves human-induced climate change alteration on faunal composition; mortality of temperature sensitive species; alien invasions, habitat loss pairaud et al., 2014; gómez-gras et al., 2022 g eologia c roatica 207berensmeier et al.: late holocene changes in the composition of foraminiferal, ostracod and molluscan communities in condensed sediments ... mouth, at 31 m water depth (fig. 1). this 3-m-long core, 16 cm in diameter, comprises holocene sediments, of which the upper 75 cm represent the holocene marine transgression. the sedimentology, stratigraphy, and geochemistry of the core and its sequence-stratigraphic framework and facies are described in berensmeier et al. (2023) and follow the regional-scale holocene facies architecture of the po coastal plain and delta (e.g., amorosi et al., 2017; bruno et al., 2017; campo et al., 2017). based on faunal content and core chronology, the studied core section is divided into four facies from bottom to top: (i) shell-poor, bioturbated sandy silts (40 – 75 cm), (ii) silty sands (22.5 – 40 cm), and (iii) a shelly lag (10 – 22.5 cm), which together represent the transgressive systems tract, and (iv) shell-poor, bioturbated muddy silts belonging to the highstand systems tract (0 – 10 cm) (fig. 2). the assignment of the facies to the depositional sequences was discussed in berensmeier et al. (2023), who documented two major stratigraphic surfaces in the record: the maximum flooding surface and the wave ravinement surface (fig. 2). these two surfaces define the general sequence stratigraphic architecture of the studied core, which is consistent with the regional architecture in the northwestern adriatic (e.g., amorosi et al., 2017; scarponi et al., 2017). while the maximum flooding surface marks the transition from a transgression to regression (amorosi & colalongo, 2009), the wave ravinement surface forms in shallow-water settings during transgression (zecchin et al., 2019, and references therein). the core was sliced into 2.5-cm thick increments in the upper part (0 – 22.5-cm core depth) and into 5-cm-thick increments in the remaining part. bulk sediment geochemistry was shown in berensmeier et al. (2023). increased nitrogen and heavy metal concentrations, such as mercury, are detected in core depths 0 – 10 cm, suggesting eutrophication and pollution impacting the study area in the last centuries. the upper 75 cm of the core were deposited under very low net sedimentation rates over the past ≈ 10,000 years, as indicated by the ages of bivalve shells (varicorbula gibba, lentidium mediterraneum) dated with radiocarbon-calibrated amino acid racefigure 1. location of the sampling station in the northern adriatic sea. a satellite image of italy and its surrounding sub-basins of the mediterranean sea. modis satellite image (terra) of the northern adriatic coast (eoimages, 2024), collected on day 335, 2002, at 1030 greenwich mean time (gmt); b bathymetric map of the study area, including the core position, ca. 30 km off the po della pila mouth. approximate core/sampling station from other studies: a – gallmetzer et al., 2019, core venice; b – gallmetzer et al., 2019, nawrot et al., 2022, cores piran 1-2; c – tomašových et al., 2017, 2018, core panzano; d – tomašových et al., 2017, core po 3; e – tomašových et al., 2017, core po 4; f – barmawidjaja et al., 1995, core 108; g – hrs-brenko, 2006, station sj101; h – picone et al., 2008, core aal87-19; i – picone et al., 2008, core ama88-39. figure 2. stratigraphic framework and geochronological data of the core from berensmeier et al. (2023). median ages are based on age-dated shells of varicorbula gibba, lentidium mediterraneum, and plant remains, all ages in years before the year the core was collected (ad2017). g eo lo gi a c ro at ic a 208 geologia croatica 78/3 mization (aar) methods and 210pb dating of the sediments (berensmeier et al., 2023). the median postmortem ages (varicorbula gibba, lentidium mediterraneum, and coralline algae) increase down-core (berensmeier et al., 2023). with the exception of centennial time-averaging in the uppermost increment (interquartile age range (iqr) of 300 years at 0 – 2.5 cm), the majority of the subsurface record at this site is affected by millennial time-averaging (3,400 years at 5 – 7.5 cm, 1,900 years at 10 – 12.5 cm and 3,000 years at 17.5 – 20 cm) and a sedimentation rate of ≈ 0.1 mm/yr (berensmeier et al., 2023). the assemblages formed by all skeletal remains in the gravity core are termed here as fossil assemblages. the term subfossil is not used here despite shell ages younger than 10,000 years. 2.2. palaeoecological analyses the benthic foraminiferal and ostracod assemblage analysis was performed on subsamples taken from each increment. these subsamples had a volume of circa 30 cm3 in the uppermost 22.5 cm and 60 cm3 in the remaining part of the core. each subsample was sieved through a 63 µm mesh size and standardised using a microsplitter. a minimum number of 300 benthic foraminiferal tests was counted in each sample of the upper 50 cm of the core. below that depth, at least 250 tests per increment were counted due to low faunal density. another subsample from each increment, representing the same volume of sediment used for foraminiferal analysis, was sieved for sieve size fractions 1 mm – 250 µm and 250 – 125 µm, in which all adult ostracod valves were identified and counted. all material >1 mm, including subsamples for benthic foraminifera and ostracods, was used to count molluscan remains. for each bivalve species, the higher number of single valves (either right or left) was added to the number of articulated specimens to get the minimum number of unique individuals in each increment. gastropods were counted if at least 50% of the shell was preserved and the aperture was present. only scaphopods with unbroken shell openings were counted. in polyplacophorans, abundance was assessed by adding the number of head valves (each representing one individual) to the number of other plates divided by eight, with decimal places rounded to integers (see supplement 1 for a complete list of species and their abundances in each core increment). the focus was on the marine species; freshwater or terrestrial taxa (mainly occurring at the base of the core) are rare and reworked and thus were omitted from analyses. the classification of benthic foraminifera at the species level is based on the criteria of loeblich & tappan (1987). the resulting species names were standardised according to the world register of marine species (worms, ahyong et al., 2025). due to poor preservation of the tests, the most common benthic foraminifera identified as haynesina germanica and haynesina sp. were summarised as haynesina spp. small tests of ammonia sp. that were not identified to the species level were pooled with other ammonia species (a. beccarii, a. inflata, a. tepida) into ammonia spp. similarly, textularia agglutinans, t. bocki, and t. conica were pooled into textularia spp. faunal densities of each taxon were calculated as the number of unique individuals divided by the volume of the entire or subsampled increment. species diversity is reported as (i) the total number of species in each increment or subsample, (ii) the shannon diversity index (effective number of species, exponential of the shannon entropy h), and (iii) the fisher’s α index. the two calculated diversity indices, shannon and fisher’s α, capture different aspects of diversity. the shannon diversity index is a measure of entropy (uncertainty in species identity of a randomly selected individual) and considers the equal distribution of individuals across species, taking into account the abundance of each species (jost, 2007). fisher’s α index is more focused on the absolute number of species and the abundance of rare species (schulte et al., 2005). we calculate both indices to show how the diversity and heterogeneity of the three fossil assemblages (mollusc, benthic foraminifera and ostracod) changed in the stratigraphic context. to account for variability in fossil abundance, we used rarefaction to compare species richness and shannon diversity between increments. mean values of rarefied species richness and shannon diversity expected at 50 specimens with corresponding 95% confidence intervals (based on the percentile method) were calculated based on 1,000 resampling iterations. the multivariate analyses are based on proportional species and genera abundances. non-metric multidimensional scaling (nmds) based on bray-curtis distances and squareroot transformed relative abundances was used to visualise changes in the assemblage structure along the core for each of the three fossil assemblages (molluscs, benthic foraminifera and ostracods) separately, (using only samples containing a minimum number of 50 individuals per increment) following kowalewski (2015). these ordinations visualise the changes in the assemblage structure and the differences between the subsurface increments, (undisturbed by human impacts) and the uppermost core increments affected by pollution and human impacts. in addition to the nmds, constrained hierarchical cluster analyses were carried out to evaluate whether groupings of intable 2. mean relative abundances of feeding guilds and habitat preferences of the molluscan assemblages in the depositional sequences: highstand silts, 0 – 10 cm and the shelly lag 10 – 22.5 cm. all values are given in %. feeding guilds of the molluscs shelly lag highstand silts filter feeder 69 73 detritus feeder 13 14 carnivore 11 6 scavenger 4 3 grazer 2 2 chemosymbiont 1 2 habitat preferences shelly lag highstand silts infauna 77 80 epifauna, hard bottom 9 8 epifauna, soft or hard bottom 8 6 semi-infauna 2 1 epifauna on vegetation 2 1 epibiont/ectoparasite 1 3 g eologia c roatica 209berensmeier et al.: late holocene changes in the composition of foraminiferal, ostracod and molluscan communities in condensed sediments ... crements with similar faunal composition correspond to distinct stratigraphic units. the cluster analysis considers the temporal sequence of samples (patzkowsky & holland, 2012). for this purpose, the coniss algorithm from the “chclust” function of the “rioja” package was applied to the bray-curtis distance matrix (juggins, 2024). since the core comprises undisturbed and disturbed periods in the depositional history of the northern adriatic, we have calculated biotic indices measuring the ecological quality of benthic habitats based on the fossil assemblages. the marine biotic index (ambi) of borja et al. (2000), based on the tolerance of macrobenthic taxa towards pollution, was applied to the molluscan assemblages to determine temporal changes in the ecological quality status along the stratigraphic succession. version 6.0 of ambi software was used (ambi, 2024). the foram stress index (fsi, after dimiza et al., 2016) was calculated to evaluate whether foraminiferal assemblages record environmental stressors. the fsi is based on the relative abundances of sensitive and stress-tolerant (opportunistic) species according to their organic matter sensitivity (jorissen et al., 2018; dimiza et al., 2016). to classify the foraminiferal species according to their stress sensitivity or tolerance, the methods of jorissen et al. (2018) and žvab rožič et al. (2022) and the reference therein were followed. the enhanced benthic foraminifera oxygen index (ebfoi) was calculated based on relative abundances of species typical of oxic, suboxic or dysoxic environments (kranner et al., 2022). all statistical analyses were performed in r 4.0.3 and rstudio version 2023.12.0.369 (r core team, 2021; posit team, 2023) using the “vegan” package (oksanen et al., 2025). 3. results 3.1. species composition three benthic phyla dominate the core’s fossil content in different grain size fractions: mollusca dominate the >1 mm size fraction, ostracoda the125 µm – 1 mm, and foraminifera the 63 µm – 125 µm. these three groups share the same up-core pattern in densities: (i) low densities below the shelly lag (75 – 22.5 cm), (ii) a maximum density in the shelly lag (22.5 – 10 cm), and (iii) an abrupt decrease in the top 10 cm (fig. 3). the molluscan total assemblage comprises 3180 bivalve individuals (56 species), 1009 gastropods (43 species), 102 scaphopods (1 species), and 12 polyplacophorans (2 species). the most abundant species is the shallow-burrowing, suspension-feeding bivalve varicorbula gibba that can also feed on resuspended detritus and benthic diatoms (yonge, 1946; kiørboe & møhlenberg, 1981; hrs-brenko, 2006), and the semi-infaunal, filter-feeding gastropod turritellinella tricarinata (fig. 4). all scaphopods belong to the infaunal micro-carnivore antalis inaequicostata. polyplacophorans are represented by chiton olivaceus and acanthochitona fascicularis. the 15 most abundant molluscan species comprise about 70% of the molluscan assemblages. the molluscan density increases gradually from 40 cm up-core, from less than 3, to 134 molluscs per 100 cm3 (fig. 3). the shelly lag bears the highest densities of all mollusc species (fig. 4). in the overlying highstand silts, the faunal densities decrease again. formerly abundant species such as parvicardium scabrum, ostrea spp., or nucula cf. nucleus decrease in relative abundance, whereas t. tricarinata increases to 16% (fig. 4). the foraminiferal total assemblage comprises 8937 individual tests (65 species and 23 genera in open nomenclature). the foraminiferal assemblages are dominated by rotaliida (table 3). the most abundant taxa are the rotaliids haynesina spp. (forming 10 – 36% of the assemblages) and ammonia spp. (11 – 26%), followed by the textulariid textularia spp. (4 – 16%). the 15 most common benthic foraminifera form about 72% of the total assemblage (fig. 5). foraminiferal densities decrease significantly at 70 cm, and no benthic foraminifera were found below 77.5 cm. within the shelly lag, the foraminiferal density peaks at ≈ 940 individuals per 1 cm3 (fig. 3). in the highstand silts, the foraminiferal densities decreased drastically, apart from representatives of nonionella sp., which were more numerous in this interval (ca. 11% of the foraminiferal assemblages). the ostracod total assemblage comprises 2528 individuals (12 species and 7 genus-level taxa). most ostracods belong to marine species, except two non-marine species that attain less than 1% of the total assemblage: cyprideis torosa (brackish) and candona sp. (freshwater). an additional six taxa configure 3. faunal densities, species richness, shannon and fisher diversity of the ostracod, foraminiferal and molluscan assemblages. maximum values of fossil density are indicated next to the graphs; faunal densities of all three taxa peak within the shell lag. a decrease in species richness and shannon diversity in the highstand silts is only recorded in the molluscan assemblages. g eo lo gi a c ro at ic a 210 geologia croatica 78/3 stitute less than 1% of the total ostracod assemblage and are not displayed in figure 6: aglayocypris sp., aurila spp. (a. convexa and a. speyeri), loxoconcha rhomboidea, semicytherura cribriformis, semicytherura sp., xestoleberis communis. the ostracod assemblages are strongly dominated by the marine species cytheridea neapolitana, which forms up to 53% of the assemblages. ostracod densities remain below 10 valves per increment below 40 cm core depth. they increase above 50 cm, reaching the highest density in the shelly lag, followed by a substantial decrease in density in the highstand silts (fig. 3). the relative abundances show that c. neapolitana remains the dominant species throughout the whole core (fig. 6). however, several taxa increase in relative abundance in the uppermost layers, including loxoconcha sp., cystacythereis sp. and callistocythere adriatica. 3.2. functional groups filter feeders dominate the molluscan assemblages, while other feeding guilds, such as detritus feeders and carnivores, are rare (table 2; fig. 7a). when comparing the mean relative abundances of feeding guilds between the shelly lag and highstand silts, filter feeders and detritus feeders increase in the latter. in contrast, higher trophic levels, such as carnivores and scavengers, decrease (table 2; fig. 7a). however, it is the infaunal and semi-infaunal species that truly dominate the molluscan assemblages with a relative abundance of ≈ 80%. in comparison, epifaunal molluscs constitute ≈ 20% of the molluscan assemblages (table 2; fig. 7b). in the rotaliidadominated total foraminiferal assemblage (fig. 7c–d; table 3), epifaunal/infaunal and epiphytic/infaunal species are the most common. similarly, the functional composition of ostracod assemblages remains relatively constant throughout the core and consists mainly of stenohaline species. brackish and freshwater species are singletons and can be regarded as reworked specimens. all observed ostracod species belong to the subclass podocopa and are benthic mobile detritus-feeders. 3.3. species diversity the raw species richness, shannon and fisher diversity indices of the molluscan assemblages increase up-core (fig. 3). the molluscan species richness reaches 68 species in the shelly lag. it decreases up-core to 26 species in the highstand silts. the hill-transformed shannon diversity of the molluscan assemblages peaks in the shelly lag at 29.7 and decreases to 16.1 in the highstand silts, and fisher’s index peaks with 22 at table 3. mean relative abundances of benthic foraminiferal orders and habitat preferences in the depositional sequences: highstand silts, 0 – 10 cm and the shelly lag 10 – 22.5 cm. all values are given in %. orders shelly lag highstand silts rotaliina 80 80 textulariina 13 13 miliolina 6 7 habitat preferences shelly lag highstand silts epifauna 8 6 epiphytic 20 17 infauna 3 12 mixed preferences 69 65 figure 4. faunal densities and relative abundances of the most abundant species of the molluscan assemblages. g eologia c roatica 211berensmeier et al.: late holocene changes in the composition of foraminiferal, ostracod and molluscan communities in condensed sediments ... figure 5. faunal densities and relative abundances of the most abundant species of the benthic foraminiferal assemblages. figure 6. faunal densities and relative abundances of the most abundant species of the ostracod assemblages. g eo lo gi a c ro at ic a 212 geologia croatica 78/3 figure 7. feeding guilds a and habitat preferences b of the molluscan assemblages, and orders c and habitat preferences d of the benthic foramini feral assemblages. each increment has been analysed for its species composition and displayed here as faunal densities (absolute number of individuals/ volume of the sample) and relative abundance (decimal). g eologia c roatica 213berensmeier et al.: late holocene changes in the composition of foraminiferal, ostracod and molluscan communities in condensed sediments ... 7.5 – 10 cm, and also decreases to 14.8 within the highstand silts. the maximum diversity of the total molluscan assemblage is recorded within the shelly lag or slightly above, followed by a remarkable drop in the highstand silts (fig. 3). raw foraminiferal species richness ranges from 18 to 29 species in the shelly lag and from 21 to 29 in the highstand silts (fig. 3). shannon diversities of the foraminiferal assemblages increase from around 9 in the shelly lag to 13.5 in the highstand silts (fig. 3). fisher’s index is slightly higher in the highstand silts (ranging from 4.8 and 7.4) than in the shelly lag (range from 4.2 to 5.6) (fig. 3). although the foraminiferal densities decrease in the uppermost 10 cm, their species richness and diversity do not decline significantly in the assemblages of the highstand silts. ostracod species richness ranges from 12 to 16 taxa in the shelly lag and from 11 to 14 taxa in the highstand silts (fig. 3). their hill-transformed shannon diversities range from 4.7 to 6.5 in the shelly lag, and decrease in the highstand silts to 3.5. the fisher’s α of the ostracod assemblages fluctuates from 2.5 to 4 in the shelly lag, and ranges from 2.7 to 4.4 in the highstand silts (fig. 3). the species richness and diversity of the ostracod assemblages do not change significantly in the highstand silts despite the drop in density. the rarefied molluscan diversity reveals a slight decrease in the highstand silts, but the diversity of benthic foraminiferal and ostracod assemblages shows no significant shifts within the record (fig. 8). 3.4. multivariate patterns in assemblage species composition the nmds ordination shows an up-core shift in the molluscan composition along the first nmds axis, with a larger separation between assemblages at the base of the core on one hand and assemblages from the shelly lag and the highstand silts on the other (fig. 9a). the constrained clustering indicates that the highstand silts (0 – 10 cm, last 2,000 yrs bp) differ in the molluscan composition relative to the extended shelly lag (10 – 40 cm), while the assemblages in transgressive sediments (2,000 – 7,800 yrs bp) are highly variable in composition (especially at 45 – 60 cm) and are less similar to those from the upper core increments (fig. 9a). similar to the molluscs, the nmds ordination of the foraminiferal assemblage shows an up-core shift along the first nmds axis and very high dispersion among assemblages occurring in the lowermost increments (50 – 75 cm, fig. 9b). the nmds ordination based on the ostracod assemblages reveals high similarity in the species composition among assemblages within the upper 30 cm of the core, with higher dispersion of assemblages at 30 – 40 cm (fig. 9c). the mantel test shows a positive spearman correlation between molluscan and foraminiferal bray-curtis dissimilarities (rho = 0.55, p < 0.001), indicating that temporal changes in the composition of assemblages are shared by these two taxa, i.e., core increments with similar molluscan assemblages are also similar in terms of foraminiferal assemblages. in contrast, there is a low and insignificant correlation between molluscan and ostracod dissimilarities (rho = 0.18, p = 0.24). 3.5. stress indices the marine biotic index (borja et al., 2000) for molluscs is 1.19 for the shelly lag (unpolluted/undisturbed status) and 1.44 for the highstand silts (slightly polluted status). the total foraminiferal assemblage comprises 44 sensitive, 15 stress-tolerant, and 10 species of unknown stress tolerance. the number of stress-tolerant and sensitive species remains relatively constant figure 8. trends in rarefied species richness and shannon diversity along the core. shading indicates 95% confidence intervals. g eo lo gi a c ro at ic a 214 geologia croatica 78/3 throughout the core. however, the relative abundances of nonionella and bulimina increase from the shelly lag to the highstand silts. the stress-tolerant species include the most abundant genera of the total foraminiferal assemblage, haynesina spp. and ammonia spp. the foram stress index (fsi, dimiza et al., 2016) exceeds a mean value of 3.8 in the shelly lag and figure 9. non-metric multidimensional scaling ordination and constrained clustering of the three taxa. a marine molluscs; b benthic foraminifera; c marine ostracoda. all numbers indicate the increment midpoints (core depth) in cm. g eologia c roatica 215berensmeier et al.: late holocene changes in the composition of foraminiferal, ostracod and molluscan communities in condensed sediments ... 3.9 in the highstand silts. both values indicate a moderately polluted environment. the enhanced benthic foraminifera oxygen index (ebfoi, kranner et al., 2022) exceeds a mean value of 68.9 in the shelly lag and 67.7 in the highstand. both values indicate a well-oxygenated environment. 4. discussion 4.1. a stratigraphic record affected by condensation, reworking and mixing the gravity core preserves a palaeoecological marine archive of ≈ 10,000 yrs, characterised by centennial and millennial time averaging, affected by slow sedimentation (condensation), reworking, and vertical mixing of shells. varicorbula gibba shell ages span 300 years in the uppermost core increment. in contrast, they range in age by several thousand years at the base of the highstand silt and in the shelly lag (mainly 2 – 6 kyr) (berensmeier et al., 2023). median ages of the shallow-subtidal bivalve v. gibba do not overlap between the highstand silt and the shelly lag (median age is 50 years at 0 – 2.5 cm, 1380 years at 5 – 7.5 cm, 2880 years at 10 – 12.5 cm, and 4480 years at 17.5 – 20 cm). although the overlap in shell ages between the upper and the lower highstand silt increment is limited, age data demonstrate that the base of the highstand silts is already mixed with the shelly lag. postmortem ages of the intertidal bivalve l. mediterraneum do not vary systematically within the upper 60 cm, with all shell ages ranging between 9380 and 10 510 cal years ad2017 (fig. 2), indicating substantial post-depositional mixing of very old shells across the highstand silts and the shelly lag, induced either by bioturbation and/or by their transport from adjacent locations. however, this species is numerically rare and does not significantly alter the overall molluscan composition (berensmeier et al., 2023). to conclude, the shelly lag is characterised by millennialscale time averaging. it thus integrates across molluscan, foraminiferal and ostracod communities that inhabited the seafloor prior to the anthropogenic impacts in the northern adriatic sea (from ≈ 2 kyr bp up to ≈ 6 kyr bp). although the lowermost increments of the overlying silts are still mixed with the shelly lag, the shell-poor, organic and metal-rich silts at the top of the core are less time-averaged and less affected by mixing with the underlying strata. in contrast, as the shelly lag does not contain shells from recent centuries, its fossil assemblages with molluscs, benthic foraminifera, and ostracods can be representative of pre-impact conditions. however, the highstand silts probably represent the mixture of preand post-impact conditions, and even the uppermost increment, averaging across the past ≈ 300 years, can be expected to integrate across distinct phases of the eutrophication history. although the upward decline in macroand microfaunal densities between the shelly lag and the highstand silts can reflect a substantial decline in benthic production, a positive correlation between molluscan fossil density and sample size-independent diversity is observed in this core (tomašových et al., 2024). this positive correlation indicates that the decline in fossil density reflects an increase in sedimentation rate over the past centuries and thus does not necessarily correspond to any temporal change in standing population densities of molluscs, benthic foraminifers or ostracods. analyses of a total foraminiferal assemblage collected in a sediment core at a muddy site location in the po delta not far from our coring location also indicate that sedimentation rates increased during the 19th and 20th centuries (barmawidjaja et al., 1995). 4.2. the shelly lag as a compositional baseline as interpreted above, relative abundances of molluscs, benthic foraminifera, and ostracods in the shelly lag represent a timeaveraged compositional baseline for assemblages inhabiting sub-tidal, muddy habitats in the northern adriatic sea. the molluscan, foraminiferal and ostracod assemblages in the shelly lag are dominated by opportunistic taxa such as v. gibba, haynesina spp. and c. neapolitana, that typically tolerate organic enrichment, pollution and some degree of oxygen depletion (table 4). however, the relative abundances of haynesina spp., and c. neapolitana decline in the overlying highstand silts. moreover, shelly lag assemblages also include species that are relatively sensitive to pollution and organic enrichment, e.g. the molluscs t. tricarinata, timoclea ovata, parvicardium scabrum, and papillicardium papillosum (e.g., nerlović et al., 2011; tomašových et al., 2018) and benthic foraminifera neoconorbina terquemi, asterigerinata mamilla or elphidium crispum. the shell lag assemblage reflects a moderately diverse molluscan community (or set of communities) dominated by filter feeders and infaunal species preferring soft bottoms. the diversity values are similar to the other holocene assemblages exhibiting millennial time averaging at other sub-tidal locations affected by low sedimentation rates in the northern adriatic sea (gallmetzer et al., 2019; tomašových et al., 2020, 2024; picone et al., 2008; barbieri et al., 2019). the microfaunal assemblage within the shelly lag is characterised by stenohaline ostracods and a highly diverse shallow-water benthic foraminiferal fauna. table 4. the dominant species of each total assemblage (molluscan, benthic foraminiferal, and ostracod) and their responses to environmental stressors. total assemblage dominant species response to organic pollution response to heavy metal pollution response to oxygen depletion used as index species ecogroup molluscs varicorbula gibba very tolerant (hrs-brenko, 2006) tolerant (gallmetzer et al., 2017) tolerant (hrs-brenko, 2006) moraitis et al., 2018; tomašových et al., 2017, 2018 species that are tolerant to organic matter enrichment (group iii after borja et al., 2000) benthic foraminifera haynesina spp. (mostly h. depressula and h. germanica) tolerant (vidović et al., 2009; bergin et al., 2006; barbieri et al., 2019) tolerant (bergin et al., 2006; žvab rožič et al., 2022) moderately tolerant (glock, 2023) melis et al., 2019; žvab rožič et al., 2022 species that are indifferent to or relatively favoured by organic enrichment (group ii and iii after jorissen et al., 2018) ostracods cytheridea neapolitana tolerant (barbieri et al., 2019) ostracods are, in general, sensitive ruiz et al., 2005; salvi et al., 2015 tolerant (barbieri et al., 2019) barbieri et al., 2019 opportunist g eo lo gi a c ro at ic a 216 geologia croatica 78/3 4.3. the human-impacted shell-poor silts the relative abundances of infaunal molluscs and benthic foraminifera increased in the highstand silts. in contrast, all other groups, particularly the epifaunal molluscs and epiphytic foraminifera, decreased from the shelly lag towards the top of the highstand silts. the foraminiferal assemblages also exhibit a significant increase in the relative abundance of infaunal species (such as nonionella sp., bulimina marginata, and bulimina aculeata) within the muddy highstand silts relative to their abundance in the shelly lag. these taxa are considered to be opportunists by jorissen et al. (2018) and dimiza et al. (2016). in contrast, the relative abundances of epiphytic species decreased (such as asterigerinata mamilla and neoconorbina terquemi). barmawidjaja et al. (1995) described a similar decrease in the relative abundance of epiphytic species close to the sampling area (see fig. 1). although v. gibba tolerates hypoxia (hrs-brenko, 2006) and organic matter enrichment (group iii of the marine biotic index, borja et al., 2000), shells of this species in the shelly lag are typically smaller than in the overlying highstand silt (berensmeier et al., 2023) where they also increase in proportional abundance, indicating stronger eutrophication during deposition of the uppermost core increments compared to the shelly lag. despite their low thickness and mixing at the base, the highstand silts are sedimentologically and geochemically distinct from the underlying shelly lag. the highstand silts correspond to an increase in fine-grained sediment accumulation over the last ≈ 2,000 years, driven by the transition from wavedominated to the river-dominated, rapidly prograding po deltaic system with prodelta lobes reaching water depths of 30 m (amorosi et al., 2019), further enhanced by a shift of the po river northwards to its present-day position ca. 800 years ago (correggiari et al., 2005). this change in sedimentary dynamics ≈ 2 kyr bp was at least partly caused by increased soil erosion and sediment discharge due to the intensification of deforestation and agriculture during the roman empire (maselli & trincardi, 2013). the shift in habitat preferences between the shelly lag and highstand matches the basin-wide trend of infaunalisation observed in live-dead studies (haselmair et al., 2021) and other sediment cores (e.g., gallmetzer et al., 2019), indicating a substantial change in soft-bottom environments in the northern adriatic sea. however, t. tricarinata, a species sensitive to pollution or seasonal oxygen depletion, even increases in relative abundance in the highstand silts. monitoring studies focusing on living assemblages and stratigraphic records from non-condensed cores in the po prodelta and gulf of trieste showed that t. tricarinata declined, whereas v. gibba increased in abundance (and also in shell size) during the 20th century (station sj101 in hrs-brenko, 2006; tomašových et al., 2017, 2018; manarini et al., 2019). the increase in turitellinella’s relative abundance can reflect conditions associated with earlier phases of eutrophication and po prodelta progradation that were not yet associated with the negative consequences of seasonal oxygen depletion or pollution. despite the stratigraphic condensation, the highstand silts preserve, to some extent, a community state that differs from the shelly lag assemblage based on the observed changes in community composition of all three taxonomic groups. 4.4. discrepancy between molluscan and foraminiferal stress indices the marine biotic index based on the molluscan assemblages (borja et al., 2000) indicates the transition from an unpolluted environment recorded in the shelly lag to a slightly polluted environment recorded in the highstand stilts. due to the insufficient percentage of foraminiferal species assigned to ecological categories based on sensitivity to organic carbon content (borja et al., 2000; borja & muxika, 2005; alve et al., 2016), the foram-ambi index was not considered for discussion. therefore, the ecological status was interpreted only by the fsi (dimiza et al., 2016). the values of the fsi (dimiza et al., 2016) indicate a slightly polluted environment in both the shelly lag and the highstand silts. although the stress indices based on molluscan and foramini feral assemblages differ to some degree, the associated changes in the relative abundances of species and functional groups in both taxa point to a partial degradation of the ecosystem status during the deposition of highstand silts relative to the deposition of the shelly lag. the discrepancy in molluscan and foraminiferal stress indices of the shelly lag could result from several factors, including (1) differing tolerances of macroand microfauna to organic enrichment or pollution, with benthic foraminifera or ostracods considered more sensitive to pollution than molluscs (yanko et al., 2003; ruiz et al., 2005; salvi et al., 2015), (2) differences in the degree of time averaging because mixing processes are known to be size-selective (however, time averaging of benthic foraminifers and molluscs was documented to be similar at other locations in the northern adriatic sea, nawrot et al., 2022), and/or (3) uncertainties related to the lack of species-level discrimination. however, the mantel test demonstrates the positive correlation between the composition of molluscan and foraminiferal assemblages, suggesting that the living communities of these two taxa responded similarly to environmental changes and that their death assemblages were not subjected to different condensation and mixing despite their differing sizes and organizational levels (single-celled versus multicellular organisms). both molluscan and foraminiferal datasets differ in the number of unassigned species, with 26% foraminiferal taxa and 14% molluscan taxa not determined to species level. the marine biotic index (borja et al., 2000) and foram stress index (dimiza et al., 2016) are expected to be calculated with less than 1% unassigned species in the molluscan assemblages, and up to 10% unassigned species in the foraminiferal assemblages. while the molluscan stress index is reliable in this regard, the foraminiferal stress index can be biased by the high proportion of individuals undetermined to species level. even with this uncertainty, the overall shift in the ambi index is congruent with the increasing relative abundances of pollution-resistant foraminifera, such as bulimina or nonionella, even when the fsi does not show any significant change. moreover, temporal changes in the relative abundances of functional groups align with the results of other palaeoecological studies about benthic foraminifera in the northern adriatic sea (e.g., barmawidjaja et al., 1995; barbieri et al., 2019, 2021). g eologia c roatica 217berensmeier et al.: late holocene changes in the composition of foraminiferal, ostracod and molluscan communities in condensed sediments ... the molluscan and foraminiferal fossil assemblages still record these ecological trends, even though they are preserved within the thin, time-averaged stratigraphic succession. 5. conclusion the gravity core collected at ≈ 30 km east of the po delta in 31 m water depth, in the northern adriatic sea, records the composition of the benthic communities that existed in the region prior to human impact (shelly lag, 2 – 6 thousand years ago bp). although the highstand silts deposited over the past two millennia average across preand post-impact community states, they show benthic and geochemical signatures of human impact. to accurately interpret the palaeoecological data, it is essential to combine fossil and stratigraphic information. even seemingly minor changes in sedimentation rates can significantly impact the temporal resolution of the fossil record. although the sediment core examined here is characterised by condensation and mixing, which obscures ecological signals within the fossil assemblages, including molluscs, benthic foraminifera, and ostracods, the shelly lag deposited prior to the onset of human impacts remains largely segregated from the highstand silts that archive the most recent changes in the community composition. changes in species abundances and functional groups reflect infaunalisation that coincides with environmental changes reconstructed from geochemical proxies. despite the incomplete nature of the fossil record, the assemblages in the shelly lag thus offer insights into a baseline largely unaffected by human impacts. at the same time, the highstand silts, while still averaging out across the past centuries, show fingerprints of eutrophication and pollution, even when the magnitude of the impact is rather minor. these data provide a foundation for future studies on multi-taxon palaeoecological datasets in the northern adriatic sea and contribute long-term information that is valuable for marine conservation efforts. acknowledgment the authors would like to thank all members of poseidon cruise no. 514, particularly chief scientist hartmut schulz, james nebelsick, and tobias b. grun, for help with sampling. ivo gallmetzer helped with the identification of molluscs. a.t. was supported by the slovak research and development agency (apvv22-0523), and the slovak scientific grant agency (vega 02/0106/23). we thank stefano dominici and one anonymous reviewer for their constructive comments, which improved this article considerably. references ager, d.v. (1973): the nature of the stratigraphical record. macmillan, distributed in the u.s.a. by halsted press, new york. alve, e., korsun, s., schönfeld, j., dijkstra, n., golikova, e., hess, s., husum, k. & panieri, g. (2016): foram-ambi: a sensitivity index based on benthic foraminiferal faunas from north-east atlantic and arctic fjords, continental shelves and slopes.– marine micropaleontology, 122, 1–12. https://doi.org/10.1016/j.marmicro.2015.11.001 ambi (2024): azti´s marine biotic index – ambi 6.0 for windows 10. amorosi, a. & colalongo, m. (2009): the linkage between alluvial and coeval nearshore marine successions: evidence from the late quaternary record of the po river plain, italy.– fluvial sedimentology, 7, 255–275. https://doi.org/10.1002/9781444304350.ch15 amorosi, a., bruno, l., campo, b., morelli, a., rossi, v., scarponi, d., hong, w., bohacs, k.m. & drexler, t.m. (2017): global sea-level control on local parasequence architecture from the holocene record of the po plain, italy.– marine and petroleum geology, 87, 99–111. https://doi.org/10.1016/j.marpetgeo.2017.01.020 amorosi, a., barbieri, g., bruno, l., campo, b., drexler, t.m., hong, w., rossi, v., sammartino, i., scarponi, d. & vaiani, s.c. (2019): three-fold nature of coastal progradation during the holocene eustatic highstand, po plain, italy – close correspondence of stratal character with distribution patterns.– sedimentology, 66, 3029– 3052. https://doi.org/10.1111/sed.12621 azzarone, m., pellegrini, c., barbieri, g., rossi, v., gamberi, f., trincardi, f. & scarponi, d. (2020): linking benthic fauna and seismic facies to improve stratigraphic reconstructions: the case of the mid-adriatic deep since the late glacial period (central adriatic sea).– bollettino della societa paleontologica italiana, 59, 9–23. https://doi. org/10.4435/bspi.2020.03 barbieri, g., rossi, v., vaiani, s.c. & horton, b.p. (2019): benthic ostracoda and foraminifera from the north adriatic sea (italy, mediterranean sea): a proxy for the depositional characterisation of river-influenced shelves.– marine micropaleontology, 153, 101772. https://doi. org/10.1016/j.marmicro.2019.101772 barbieri, g., rossi, v., vaiani, s.c., dasgupta, u. & amorosi, a. (2021): quantitative paleoecology in shallow-marine settings: the value of ostracods and foraminifers from the holocene north adriatic record.– palaeogeography, palaeoclimatology, palaeoecology, 572, 110408. https://doi.org/10.1016/j.palaeo.2021.110408 barmawidjaja, d.m., van der zwaan, g.j., jorissen, f.j. & puskaric, s. (1995): 150 years of eutrophication in the northern adriatic sea: evidence from a benthic foraminiferal record.– marine geology, 122, 367–384. https://doi.org/10.1016/0025-3227(94)00121-z berensmeier, m., tomašových, a., nawrot, r., cassin, d., zonta, r., koubová, i. & zuschin, m. (2023): stratigraphic expression of the human impacts in condensed deposits of the northern adriatic sea.– geological society, london, special publications, 529, 195–222. https://doi.org/10.1144/sp529-2022-188 bergin, f., kucuksezgin, f., uluturhan, e., barut, i.f., meric, e., avsar, n. & nazik, a. (2006): the response of benthic foraminifera and ostracoda to heavy metal pollution in gulf of izmir (eastern aegean sea).– estuarine, coastal and shelf science, 66, 368–386. https:// doi.org/10.1016/j.ecss.2005.09.013 borja, a. & muxika, i. (2005): guidelines for the use of ambi (azti’s marine biotic index) in the assessment of the benthic ecological quality.– marine pollution bulletin, 50, 787–789. https://doi.org/10.1016/j.marpolbul.2005.04.040 borja, a., franco, j. & pérez, v. (2000): a marine biotic index to establish the ecological quality of soft-bottom benthos within european estuarine and coastal environments.– marine pollution bulletin, 40, 1100–1114. https://doi.org/10.1016/s0025-326x(00)00061-8 bruno, l., amorosi, a., severi, p. & costagli, b. (2017): late quaternary aggradation rates and stratigraphic architecture of the southern po plain, italy.– basin research, 29, 234–248. https://doi.org/10.1111/ bre.12174 campo, b., amorosi, a. & vaiani, s.c. (2017): sequence stratigraphy and late quaternary paleoenvironmental evolution of the northern adriatic coastal plain (italy).– palaeogeography, palaeoclimatology, palaeoecology, 466, 265–278. https://doi.org/10.1016/j.palaeo.2016.11.016 correggiari, a., cattaneo, a. & trincardi, f. (2005): the modern po delta system: lobe switching and asymmetric prodelta growth.– marine geology, 222–223, 49–74. https://doi.org/10.1016/j.margeo.2005.06.039 crocetta, f. (2011): marine alien mollusca in the gulf of trieste and neighbouring areas: a critical review and state of knowledge (updated in 2011).– acta adriatica, 52, 247–260. https://doi.org/10.1016/j.marmicro.2015.11.001 https://doi.org/10.1111/sed.12621 g eo lo gi a c ro at ic a 218 geologia croatica 78/3 d’amico, c., aiello, g., barra, d., bracone, v., di bella, l., esu, d., frezza, v. & rosskopf, c.m. (2013): late quaternary foraminiferal, molluscan and ostracod assemblages from a core succession in the trigno river mouth area (central adriatic sea, italy).– bollettino della societa paleontologica italiana, 52, 197–205. https://doi.org/10.4435/ bspi.2013.23 devescovi, m. & iveša, l. (2007): short term impact of planktonic mucilage aggregates on macrobenthos along the istrian rocky coast (northern adriatic, croatia).– marine pollution bulletin, 54, 887–893. https:// doi.org/10.1016/j.marpolbul.2007.03.009 dietl, g.p. & flessa, k.w. (2011): conservation paleobiology: putting the dead to work.– trends in ecology & evolution, 26, 30–37. https://doi. org/10.1016/j.tree.2010.09.010 dimiza, m.d., triantaphyllou, m.v., koukousioura, o., hallock, p., simboura, n., karageorgis, a.p. & papathanasiou, e. (2016): the foram stress index: a new tool for environmental assessment of soft-bottom environments using benthic foraminifera. a case study from the saronikos gulf, greece, eastern mediterranean.– ecological indicators, 60, 611–621. https://doi.org/10.1016/j.ecolind.2015.07.030 dresow, m. (2023): biased, spasmodic, and ridiculously incomplete: sequence stratigraphy and the emergence of a new approach to stratigraphic complexity in paleobiology, 1973–1995.– journal of the history of biology, 56, 419–454. https://doi.org/10.1007/s10739-023-09720-0 frontalini, f. & coccioni, r. (2011): benthic foraminifera as bioindicators of pollution: a review of italian research over the last three decades.– revue de micropaleontologie, 54, 115–127. https://doi. org/10.1016/j.revmic.2011.03.001 gallmetzer, i., haselmair, a., tomašových, a., stachowitsch, m. & zuschin, m. (2017): responses of molluscan communities to centuries of human impact in the northern adriatic sea.– plosone, 12/7, e0180820. https://doi.org/10.1371/journal.pone.0180820 gallmetzer, i., haselmair, a., tomašových, a., mautner, a., schnedl, s., cassin, d., zonta, r. & zuschin, m. (2019): tracing origin and collapse of holocene benthic baseline communities in the northern adriatic sea.– palaios, 34, 121–145. https://doi. org/10.2110/palo.2018.068 glock, n. (2023): benthic foraminifera and gromiids from oxygen-depleted environments – survival strategies, biogeochemistry and trophic interactions.– biogeosciences, 20, 3423–3447. https://doi.org/10.5194/bg-203423-2023 gómez-gras, d., bensoussan, n., ledoux, j.b., lópez-sendino, p., cerrano, c., ferretti, e., kipson, s., bakran-petricioli, t., serrao, e.a., paulo, d., coelho, m.a.g., pearson, g.a., boavida, j., montero-serra, i., pagès-escolà, m., medrano, a., lópez-sanz, a., milanese, m., linares, c. & garrabou, j. (2022): exploring the response of a key mediterranean gorgonian to heat stress across biological and spatial scales.– scientific reports, 12, 21064. http://doi.org/10.1038/s41598-022-25565-9 haselmair, a., gallmetzer, i., tomašových, a., wieser, a., übelhör, a. & zuschin, m. (2021): basin-wide infaunalisation of benthic soft-bottom communities driven by anthropogenic habitat degradation in the northern adriatic sea.– marine ecology progress series, 671, 45–65. https://doi.org/10.3354/meps13759 hrs-brenko, m. (2006): the basket shell, corbula gibba olivi, 1792 (bivalve mollusks) as a species resistant to environmental disturbances: a review.– acta adriatica: international journal of marine sciences, 47, 49–64. jackson, j.b.c. (2001): what was natural in the coastal oceans?– proceedings of the national academy of sciences of the united states of america, 98, 5411–5418. https://doi.org/10.1073/pnas.091092898 jackson, s.t. & hobbs, r.j. (2009): ecological restoration in the light of ecological history.– science, 325, 567–569. https://doi.org/10.1126/science.1172977 jorissen, f., nardelli, m.p., almogi-labin, a., barras, c., bergamin, l., bicchi, e., el kateb, a., ferraro, l., mcgann, m., morigi, c., romano, e., sabbatini, a., schweizer, m. & spezzaferri, s. (2018): developing foram-ambi for biomonitoring in the mediterranean: species assignments to ecological categories.– marine micropaleontology. 140, 33–45. https://doi.org/10.1016/j.marmicro.2017.12.006 jost, l. (2007): partitioning diversity into independent alpha and beta components.– ecology, 88, 2427–39. https://doi.org/10.1890/06-1736.1 juggins, s. (2024): rioja: analysis of quaternary science data. r package version (1.0-7). justić, d. (1991): hypoxic conditions in the northern adriatic sea: historical development and ecological significance.– geological society special publication, 58, 95–105. https://doi.org/10.1144/gsl.sp.1991.058.01.07 kiørboe, t. & møhlenberg, f. (1981): particle selection in suspension-feeding bivalves.– marine ecology progress series, 5, 291–296. kollmann, h. & stachowitsch, m. (2008): long-term changes in the benthos of the northern adriatic sea: a phototransect approach.– marine ecology, 22, 135–154. https://doi.org/10.1046/j.1439-0485.2001.01761.x kowalewski, m. (2015): time-averaging, overcompleteness, and the geological record.– the journal of geology, 104, 317–326. http://doi. org/10.1086/629827 kranner, m., harzhauser, m., beer, c., auer, g. & piller, w.e. (2022): calculating dissolved marine oxygen values based on an enhanced benthic foraminifera oxygen index.– scientific reports, 12, 1–13. https://doi.org/10.1038/s41598-022-05295-8 kraus, r. & ivošević denardis, n. (2023): tracking the spatio-temporal distribution of organic particles to predict macroaggregation in the northern adriatic sea.– water (switzerland), 15, 1–18. https://doi. org/10.3390/w15091665 loeblich, a.r. & tappan, h. (1987): foraminiferal genera and their classification. van nostrand rheinold co. inc. new york. lotze, h.k., coll, m. & dunne, j.a. (2011): historical changes in marine resources, food-web structure and ecosystem functioning in the adriatic sea, mediterranean.– ecosystems, 14, 198–222. https://doi. org/10.1007/s10021-010-9404-8 manarini, t., strafella, p., salvalaggio, v., punzo, e. & spagnolo, a. (2019): turritella communis: an adriatic ecosystem engineer. rapport de la commission international de la mer méditerranée, 42. maselli, v. & trincardi, f. (2013): man made deltas.– scientific reports, 3, 1926. https://doi.org/10.1038/srep01926 mautner, a.k., gallmetzer, i., haselmair, a., schnedl, s.m., tomašových, a. & zuschin, m. (2018): holocene ecosystem shifts and human-induced loss of arca and ostrea shell beds in the north-eastern adriatic sea.– marine pollution bulletin, 126, 19–30. https://doi.org/10.1016/j.marpolbul.2017.10.084 melis, r., celio, m., bouchet, v.m.p., varagona, g., bazzaro, m., crosera, m. & pugliese, n. (2019): seasonal response of benthic foraminifera to anthropogenic pressure in two stations of the gulf of trieste (northern adriatic sea, italy): the marine protected area of miramare versus the servola water sewage outfall.– mediterranean marine science, 20, 120–141. https://doi.org/10.12681/mms.16154 moraitis, m.l., tsikopoulou, i., geropoulos, a., dimitriou, p.d., papageorgiou, n., giannoulaki, m., valavanis, v.d. & karakassis, i. (2018): molluscan indicator species and their potential use in ecological status assessment using species distribution modeling.– marine environmental research, 140, 10–17. https://doi.org/10.1016/j.marenvres.2018.05.020 nawrot, r., berensmeier, m., gallmetzer, i., haselmair, a., tomašových, a. & zuschin, m. (2022): multiple phyla, one time resolution? similar time averaging in benthic foraminifera, mollusk, echinoid, crustacean, and otolith fossil assemblages.– geology, 50, 902– 906. https://doi.org/10.1130/g49970.1, 2022 nawrot, r., zuschin, m., tomašových, a., kowalewski, m. & scarponi, d. (2024): ideas and perspectives: human impacts alter the marine fossil record.– biogeosciences, 21, 2177–2188. https://doi. org/10.5194/bg-21-2177-2024 https://doi.org/10.5194/bg-21-2177-2024 https://doi.org/10.5194/bg-21-2177-2024 g eologia c roatica 219berensmeier et al.: late holocene changes in the composition of foraminiferal, ostracod and molluscan communities in condensed sediments ... nerlović, v., doğan, a. & hrs-brenko, m. (2011): response to oxygen deficiency (depletion): bivalve assemblages as an indicator of ecosystem instability in the northern adriatic sea.– biologia, 66, 1114– 1126. occhipinti-ambrogi, a., marchini, a., cantone, g., castelli, a., chimenz, c., cormaci, m., froglia, c., furnari, g., gambi, m.c., giaccone, g., giangrande, a., gravili, c., mastrototaro, f., mazziotti, c., orsi-relini, l. & piraino, s. (2010): alien species along the italian coasts: an overview.– biological invasions, 13, 215–237. https://doi.org/10.1007/ s10530-010-9803-y orlando-bonaca, m. (2010): new records of non-indigenous algal species in slovenian coastal waters.– annales: series historia naturalis, 20/2, 143–150. pairaud, i.l., bensoussan, n., garreau, p., faure, v. & garrabou, j. (2014): impacts of climate change on coastal benthic ecosystems: assessing the current risk of mortality outbreaks associated with thermal stress in nw mediterranean coastal areas topical collection on the 16th biennial workshop of the joint numerical sea modelli.– ocean dynamics, 64, 103–115. https://doi.org/10.1007/s10236-013-0661-x patzkowsky, m.e. & holland, s.m. (2012): stratigraphic paleobiology.– paleobiology, 51(1), 44–61. picone, s., alvisi, f., dinelli, e., morigi, c., negri, a., ravaioli, m. & vaccaro, c. (2008): new insights on late quaternary palaeogeographic setting in the northern adriatic sea (italy).– journal of quaternary science, 23, 489–501. https://doi.org/10.1002/jqs.1152 pitcher, c.r., hiddink, j.g., jennings, s., collie, j., parma, a.m., amoroso, r., mazor, t., sciberras, m.a., mcconnaughey, r.a., rijnsdorp, a.d., kaiser, m.j., suuronen, p. & hilborn, r. (2022): trawl impacts on the relative status of biotic communities of seabed sedimentary habitats in 24 regions worldwide.– proceedings of the national academy of sciences of the united states of america, 119. https://doi.org/10.1073/pnas.2109449119r rossi, v., barbieri, g., vaiani, s.c., cacciari, m., bruno, l., campo, b., marchesini, m., marvelli, s. & amorosi, a. (2021): millennial-scale shifts in microtidal ecosystems during the holocene: dynamics and drivers of change from the po plain coastal record (ne italy).– journal of quaternary science. https://doi.org/10.1002/ jqs.3322 ruiz, f., abad, m., bodergat, a.m., carbonel, p., rodríguez-lázaro, j. & yasuhara, m. (2005): marine and brackish-water ostracods as sentinels of anthropogenic impacts.– earth-science reviews, 72, 89–111. https://doi.org/10.1016/j.earscirev.2005.04.003 salvi, g., buosi, c., arbulla, d., cherchi, a., de giudici, g., ibba, a. & de muro, s. (2015): ostracoda and foraminifera response to a contaminated environment: the case of the ex-military arsenal of the la maddalena harbour (sardinia, italy).– micropaleontology, 61, 115– 133. https://doi.org/10.47894/mpal.61.1.09 scarponi, d., azzarone, m., kusnerik, k., amorosi, a., bohacs, k.m. & drexler, t.m. (2017): systematic vertical and lateral changes in quality and time resolution of the macrofossil record: insights from holocene transgressive deposits, po coastal plain, italy.– marine and petroleum geology journal, 87, 128–136. https://doi.org/10.1016/j. marpetgeo.2017.03.031 scarponi, d., nawrot, r., azzarone, m., pellegrini, c., gamberi, f., trincardi, f. & kowalewski, m. (2022): resilient biotic response to long-term climate change in the adriatic sea.– global change biology, 28, 4041–4053. https://doi.org/10.1111/gcb.16168 schnedl, s.m., haselmair, a., gallmetzer, i., mautner, a.k., tomašových, a. & zuschin, m. (2018): molluscan benthic communities at brijuni islands (northern adriatic sea) shaped by holocene sea-level rise and recent human eutrophication and pollution.– holocene, 28, 1801–1817. https://doi.org/10.1177/0959683618788651 schulte, r.p.o., lantinga, e.a. & hawkins, m.j. (2005): a new family of fisher-curves estimates fisher’s alpha more accurately.– journal of theoretical biology, 232, 305–313. https://doi.org/10.1016/j. jtbi.2004.08.014 stachowitsch, m. (1984): mass mortality in the gulf of trieste: the course of community destruction.– marine ecology progress series, 5, 243–264. stachowitsch, m. (2014): preface: coastal hypoxia and anoxia: a multi-tiered holistic approach.– biogeosciences, 11, 2281–2285. https://doi. org/10.5194/bg-11-2281-2014 stachowitsch, m., fanuko, n. & richter, m. (1990): mucus aggregates in the adriatic sea: an overview of stages and occurrences.– marine ecology, 11, 327–350. https://doi.org/10.1111/j.1439-0485.1990. tb00387.x tomašovỳch, a., gallmetzer, i., haselmair, a., kaufman, d.s., vidović, j. & zuschin, m. (2017): stratigraphic unmixing reveals repeated hypoxia events over the past 500 yr in the northern adriatic sea.– geology, 45, 363–366. https://doi.org/10.1130/g38676.1 tomašovych, a., gallmetzer, i., haselmair, a., kaufman, d.s., kralj, m., cassin, d., zonta, r. & zuschin, m. (2018): tracing the effects of eutrophication on molluscan communities in sediment cores: outbreaks of an opportunistic species coincide with reduced bioturbation and high frequency of hypoxia in the adriatic sea.– paleobiology, 44, 575–602. https://doi.org/10.1017/pab.2018.22 tomašových, a., albano, p.g., fuksi, t., gallmetzer, i., haselmair, a., kowalewski, m., nawrot, r., nerlović, v., scarponi, d. & zuschin, m. (2020): ecological regime shift preserved in the anthropocene stratigraphic record: regime shift in the stratigraphic record.– proceedings of the royal society b: biological sciences, 287, 20200695. https://doi.org/10.1098/rspb.2020.0695rspb20200695 tomašových, a., dominici, s., nawrot, r. & zuschin, m. (2023): temporal scales, sampling designs and age distributions in marine conservation.– palaeobiology, 529, 1-39. https://doi.org/10.1144/sp5292022-361 tomašových, a., kowalewski, m., nawrot, r., scarponi, d. & zuschin, m. (2024): abundance-diversity relationship as a unique signature of temporal scaling in the fossil record.– ecology letters, 27, 1–15. https://doi.org/10.1111/ele.14470 vidović, j., ćosović, v., juračić, m. & petricioli, d. (2009): impact of fish farming on foraminiferal community, drvenik veliki island, adriatic sea, croatia.– marine pollution bulletin, 58, 1297–1309. https:// doi.org/10.1016/j.marpolbul.2009.04.031 vidović, j., nawrot, r., gallmetzer, i., haselmair, a., tomašových, a., stachowitsch, m., ćosović, v. & zuschin, m. (2016): anthropogenically induced environmental changes in the northeastern adriatic sea in the last 500 years (panzano bay, gulf of trieste).– biogeosciences, 13, 5965–5981. https://doi.org/10.5194/bg13-5965-2016 willis, k.j. & birks, h.j.b. (2006): what is natural? the need for a longterm perspective in biodiversity conservation.– science, 314, 1261–1265. https://doi.org/10.1126/science.1122667 wittmer, j.m., dexter, t.a., scarponi, d., amorosi, a. & kowalewski, m. (2014): quantitative bathymetric models for late quaternary transgressive-regressive cycles of the po plain, italy.– journal of geology, 122, 649–670. https://doi.org/10.1086/677901 yanko, v., arnold, a.j. & parker, w.c. (2003): effects of marine pollution on benthic foraminifera.– in: sen gupta, b. k. (ed.): modern foraminifera. springer, heidelberg, 217–235. https://doi.org/10.1007/0306-48104-9 yonge, c.m. (1946): on the habits of turritella communis risso.– journal of the marine biological association of the united kingdom, 26, 377– 380. cambridge university press. zecchin, m., catuneanu, o. & caffau, m. (2019): wave-ravinement surfaces: classification and key characteristics.– earth-science reviews, 188, 210–239. https://doi.org/10.1016/j.earscirev.2018.11.011 zecchin, m., caffau, m., busetti, m., masoli, c.a., baradello, l., civile, d., dal cin, m., petronio, l., romeo, https://doi.org/10.1002/jqs.1152 https://doi.org/10.1073/pnas.2109449119r https://doi.org/10.1086/677901 g eo lo gi a c ro at ic a 220 geologia croatica 78/3 r., zampa, l.s., lenaz, d., lucchi, r.g. & caburlotto, a. (2024): late quaternary transgressions and regressions in the trieste gulf (north-eastern adriatic sea).– quaternary international, 695, 1–17. https://doi.org/10.1016/j.quaint.2024.03.001 žvab rožič, p., vidović, j., ćosović, v., hlebec, a., rožič, b. & dolenec, m. (2022): a multiparametric approach to unravelling the geoenvironmental conditions in sediments of bay of koper (ne adriatic sea): indicators of benthic foraminifera and geochemistry.– frontiers in marine science, 9, 1–18. https://doi.org/10.3389/fmars.2022.812622 web sources: ahyong, s., boyko, c.b., mees, j., bernot, j., brandão, s.n., daly, m., de grave, s., de voogd, n.j., gofas, s., hernandez, f., neubauer, t.a., paulay, g., van der meji, s., boydens, b., decock, w., dekeyzer, s., goharimanesh, m., vandepitte, l., vanhoorne, b. et al. (2025): world register of marine species (worms). available at: https://www.marinespecies.org. accessed on: 10th january, 2025. eoimages (2024): modis satellite image (terra) of the northern adriatic coast. available at: https://eoimages.gsfc.nasa.gov/images/imagerecords/59000/59211italy.a2002138.1010.250m.jpg. accessed on: 10th march, 2024. oksanen, j., simpson, g., blanchet, f., kindt, r., legendre, p., minchin, p., o'hara, r., solymos, p., stevens, m., szoecs, e., wagner, h., barbour, m., bedward, m., bolker, b., borcard, d., borman, t., carvalho, g., chirico, m., de caceres, m., durand, s., evangelista, h., fitzjohn r., friendly, m., furneaux, b., hannigan, g., hill, m., lahti, l., martino, c., mcglinn d., ouellette, m., ribeiro cunha, e., smith, t., stier, a., ter braak, c. & weedon, j. (2025): vegan: community ecology package. r package version 2.8-0. available at: https://vegandevs.github.io/ vegan/. accessed on: 10th january, 2025. posit team (2023): rstudio: integrated development environment for r. posit software, pbc, boston, ma. available at: http://www.posit.co/. accessed on: 10th january, 2025. r core team (2021): r: a language and environment for statistical computing. r foundation for statistical computing, vienna, austria. available at: https://www.r-project.org/. accessed on: 10th january, 2025. supplementary material electronic supplementary material is available online with the article at https://www.geologia-croatica.hr https://doi.org/10.3389/fmars.2022.812622 https://www.marinespecies.org https://eoimages.gsfc.nasa.gov/images/imagerecords/59000/59211/italy.a2002138.1010.250m.jpg https://eoimages.gsfc.nasa.gov/images/imagerecords/59000/59211/italy.a2002138.1010.250m.jpg https://www.r-project.org/ https://www.geologia-croatica.hr  fluid inclusion study of the boccassuolo vms-related stockwork deposit (northern apennine ophiolites, italy)  gabriella b. kiss department of mineralogy, eötvös loránd university, 1/c pázmány péter sétány, budapest, hungary, h-1117; (gabriella.b.kiss@ttk.elte.hu) doi: 104154/gc.2015.22 ab stra ct several cyprus-type volcanogenic massive sulphide (vms) deposits occur in the jurassic ophiolitic series of the northern apennines. stratabound, stratiform and stockwork deposits were formed in the western limb of the neotethys (ligurian ocean) and are observed today in basalt, gabbro and serpentinised peridotite host rocks. the studied stockwork deposit at boccassuolo occurs in basalt and basalt breccia. detailed petrography, fluid inclusion study, raman spectroscopy analyses and chlorite thermometry calculations were used to determine the p, t, x conditions of the fluid circulation system. the veins contain three quartz generations, calcite, chlorite, epidote and sericite as gangue minerals and pyrite, chalcopyrite, sphalerite, pyrrhotite and galena as ore minerals. based on the fluid inclusion study, the earlier defined three vein types (1, 2 and 3) precipitated from the same type of evolving fluid, though at slightly different stratigraphic positions. the determined ranges of temperature (370‑60°c), salinity (6.2‑11.4 nacl equiv. wt%), pressure (30‑44 mpa) and methane content (average 0.28 mol/kg) suggest an evolved seawater origin for the hydrothermal fluid, modified by fluid‑rock interactions and possibly by mixing of magmatic volatiles. the fluid characteristics and the mineralogical observations have proven a slightly distal position in relation to the centre of the fluid flow for all the studied locations, but more central and more distant blocks were also recognised. the temporal evolution of the system developed into a low temperature event, occurring after the main mineral stage of formation, but still within the same overall process. keywords: hydrothermal processes, vms deposit, ophiolite, northern‑apennines, fluid inclusions, raman spectroscopy historical mining activity at boccassuolo enables research at several levels of the stockwork mineralisation. this convenient situation allows modelling the vertical and horizontal features of the mineralised hydrothermal system. in spite of this, only an attempt to evaluate the temperature of the mineralised fluids in boccassuolo was done by using a chlorite geothermometer (zaccarini & garuti, 2008), but a detailed description of the characteristics of the hydrothermal fluids is not currently available. the present study describes this phenomenon more precisely, with the help of detailed fluid inclusion microthermometry, raman spectro‑ scopy and chlorite thermometry studies in all three types of boccassuolo veins. characteristics of the p, t, x conditions of the hydrothermal fluid helps to link genetically the three vein‑types and allows a model of the fluid circulation system 1. introduction numerous volcanogenic massive sulphide (vms) deposits with a cyprus-type metallogenic signature (cu-fe-zn) occur in the tethyan jurassic ophiolites (the ligurides) of the italian northern apennines. one of these deposits, boccassuolo, is located close to the city of modena. it consists of sulphide mineralisation in quartz veins which cut across pillow-basalt and basalt breccia. this stockwork mineralisation consists of pyrite, chalcopyrite, and sphalerite, with (in the upper levels), galena, occurring together with quartz, calcite and chlorite (see e.g. garuti et al., 2008, 2011 and the re‑ ferences therein). on the basis of the pb-ag-au-zn-cu distribution pattern, garuti et al. (2011) recognised three major types of mineralised veins. geologia croatica 68/3 285–302 8 figs. 4 tabs. zagreb 2015 geologia croaticageologia croatica geologia croatica 68/3geologia croatica 286 asymmetric extension induced by a detachment fault initially caused the subcontinental mantle to be intruded by small gabbroic plutons and mafic dykes (from the triassic to the middle jurassic). as a consequence of continental breakup, the peridotite‑gabbro basement was exposed and deeply eroded at the floor of the incipient ocean (the piedmont‑liguria basin). extensive formation of thick horizons of ophicalcite and serpentinite-gabbro breccia marked these initial episodes of seafloor erosion (cortesogno et al., 1978, principi et al., 1992). further ocean opening occurred in a slow-spreading regime producing scattered and limited extrusion of morb‑type lava lying directly on the plutonic rocks (barrett, 1982; lemoine et al., 1987; lagabrielle & lemoine, 1997; piccardo et al., 2002). the upwelling mafic magma provided the heat for the establishment of convective hydrothermal cells across the ligurian sub‑oceanic crust and led to the consequent formation of vms-type cu-sulphide deposits, characterised by their different ore composition and sulphur isotope signature to be established. it could serve also as a base for future work in the other ligurian vms deposits. furthermore, comparison of the temperature obtained using fluid inclusion microthermometry with those calculated with a chlorite geothermometer allows us to evaluate the research efficiency of this latter approach. 2. regional geology and description of the vms deposits the small mass of ophiolite of boccassuolo pertains to the ligurian ophiolite belt (fig. 1a) extending from the wes‑ tern alps to the northern apennines and northeastern corsica (garuti et al., 2008, 2011, and references therein). the ligurian ophiolites formed in the westernmost limb of the neotethys by rifting of the adria and european continental plates. they are considered as typical examples of subduction-unrelated, continental margin ophiolites (barrett, 1982; piccardo et al., 2002; dilek & furnes, 2011, 2014). figure 1: structural sketch of the ophiolites of the northern apennines (a) and a simplified geological map of the boccassuolo ophiolite (b) (garuti et al. 2011). the location of figure 1b is marked with the sign bo on figure 1a. figure 1b shows the sampling sites (numbers 1-8 in circles) and the elevations (italic numbers, in metres) above sea level. the ophiolite locations discussed in the text are: bc-monte bianco, bd-monte bardeneto, bo-boccassuolo, co-corchia, cp-campegli, cs-casali, fe-ferriere, gr-groppallo, lb-libiola, mo-montecreto, rp-reppia, vi-vigonzano. the parts of the boccassuolo ophiolite are: cc-cinghio del corvo, ll-cascina lame, mc-madonna del calvario, pbd-poggio bianco dragone, pm-poggio medola. kiss: fluid inclusion study of the boccassuolo vms-related stockwork deposit (northern apennine ophiolites, italy) geologia croatica 287 according to their distinctive structural position in the ophiolite stratigraphy (ferrario & garuti, 1980; garuti & zaccarini, 2005; garuti et al., 2008, 2009). hydrothermal activity, preceding the outflow of basaltic lava, gene‑ rated deposition of sulphides in stockwork-veins crosscutting the peridotite-gabbro basement (at vigonzano, ferriere, groppallo, santa maria and campegli), and in the formation of stratiform ore bodies within the seafloor serpentinite breccia (at monte bardeneto, reppia and monte bianco). the seafloor‑stratiform deposits are invariably covered with pillow lava flows, whereas no significant deposition of sulphide was observed in the serpentinite breccia overlain by sediments. this observation supports the conclusion that formation of hydrothermal cells and subsequent discharge of me‑ tals on the seafloor were essentially focused around centres of uprising magma, during a relatively long volcanic hiatus preceding the basalt extrusion (garuti et al., 2008). the hydrothermal activity continued during and after basalt outflow, thereby sulphides were deposited in crosscutting stockwork-veins (at casali, reppia, monte bianco, montecreto and boccassuolo) and conformable ore bodies within the basalt unit, as well as in seafloor‑stratiform ore bodies on top of the volcanic pile (at reppia, corchia and libiola) (fig. 1a) (zaccarini & garuti, 2008). the overlying rocks of the vms-bearing oceanic units are pelagic sediments. firstly radiolarian chert (upper jurassic) was deposited, accompanied by intensive exhalative hydrothermal activity leading to the formation of huge manganese deposits (bonatti et al., 1976; cabella et al., 1998). progressive regression of the oceanic crust from the axial rifting zone was marked by burial of the ophiolitic basement under a thick cover of pelagic sediments, mainly represented by calpionella limestone and palombini shale (lowerto upper-cretaceous), overlain by various types of arenaceous turbidites (upper-cretaceous to palaeocene). palombini shale may occur also as a sedimentary intercalation within the pillow basalt (e.g. at boccassuolo) and can be found as a component of „debris‑flow‑type” polygenic breccia (together with chert, basalt, serpentinite and rare granite), indicating that continuing episodes of seafloor erosion occurred at intervals coeval with basaltic volcanism and pelagic sedimentation. this geotectonic evolution resulted in the build-up of the anomalous architecture of the ligurian ophiolites, consisting of weakly depleted subcontinental mantle, directly overlain by a volcano-sedimentary cover with thick accumulations of ophiolitic breccia, but lacking a true, mafic‑ultramafic cumulus pile and sheeted‑dyke complex, which are typical members of the conventional ophiolite stratigraphy (barrett & spooner, 1977; abbate et al., 1980; barrett, 1982; cortesogno et al., 1987; lemoine et al., 1987; principi et al., 1992; piccardo et al., 2002). convergence across the piedmont-liguria basin (upper-cretaceous to eocene) resulted in subduction of the western limb of the oceanic crust beneath the adria continental margin. the subducted oceanic lithosphere and associated sulphide deposits underwent eclogite-facies metamorphism and during the alpine orogeny, were obducted along the western alps and the western liguria apennines (dal piaz, 1974 a,b; pognante & piccardo, 1984; lombardo et al., 2002). in contrast, large fragments of oceanic lithosphere preserved from the high-p, low-t metamorphism, are presently exposed in the northern apennines, between eastern liguria and southwest emilia romagna and partly in northeastern corsica. these ophiolites and related sulphide deposits of the northern apennines show the effects of sub-oceanic hydrothermal metasomatism (barrett & freidrichsen, 1989), or weak metamorphism to the lower limit of the prehnite-pumpellyite facies and orogenic deformation in a cold regime (cortesogno et al. 1975). mineralogy of shale from the sedimentary cover reflects p‑t conditions compatible with extreme burial diagenesis (leoni et al., 1998; zaccarini & garuti, 2008). these ophiolites form a composite nappe in which fragments of oceanic crust proximal to the axial rifting zone (internal ligurides) are thrust northeastward over ophiolites and sediments exhumed from more distal zones, close to the adria continental margin (external ligurides). the internal ligurides consist of ne-verging blocks bounded by southwestward dipping faults, in which stratigraphic contact between ophiolites and sedimentary cover is commonly preserved (elter, 1975; barrett, 1982). the external ligurides are characterised by dismembered ophiolitic blocks of kilometre to metre size, embedded in a mélange formed by polyphase tectonic disruption of the cretaceous sedimentary cover (fig. 1a) (pini, 1999). due to the intense tectonism, stratigraphic relationships among ophiolite units are preserved only inside the largest ophiolite blocks (garuti et al., 2008). 3. the geology of the boccassuolo ophiolite the boccassuolo ophiolite (fig. 1b), preserved from the high p low t metamorphism, is located in the external ligurides, at about 44° 18’ n and 10° 37’ e, southwest of the city of modena (emilia romagna). the ophiolitic rocks form a n‑s elongated body of about 4 x 1.5 km, composed of two major blocks: poggio bianco dragone to the north and cinghio del corvo to the south, separated by a nw‑se trending subvertical fault (garuti et al., 2011). the ophiolite is made up of an alternation of lava flows (pillow and massive basalt) intercalated with several metre thick horizons of ophiolitic sediments (breccia and sandstone), composed of clasts of basalt, chert, limestone and rare serpentinite and granite. these ophiolitic rocks tectonically overlie strongly deformed carbonaceous‑argillaceous sediments, poorly exposed at the northeastern border of the ophiolite. no mafic‑ ultramafic basement has been observed at boccassuolo. close to the top of the cinghio del corvo block (1079 m), pillow and pillow breccias are stratigraphically capped by siliciclastic sediments containing thin layers of mn-rich clay (early pelagic sedimentation?), although, the original presence of a thick formation of chert in the sedimentary cover of the boccassuolo ophiolite is supported by the occurrence of large blocks (up to several metres in size) of radiolarian chert geologia croatica 68/3geologia croatica 288 within the ophiolitic breccia. the ophiolitic rocks of the poggio bianco dragone block reach a maximum exposed thickness of about 350 m, with a general attitude varying from nw‑dipping (~10° to 45° degrees) at the base, to nearly horizontal close to the top. the original thickness of the entire volcano-sedimentary pile is estimated to have not exceeded 500 m, from a possible ultramafic footwall to the overlying sedimentary cover (plesi et al., 2002). 4. the mineralisation of the boccassuolo vms deposit the sulphide deposit of boccassuolo (fig. 1b) consists of a reticulate stockwork of quartz‑calcite‑chlorite‑sulphide veins emplaced in pillow basalt and ophiolitic breccia (zaccarini & garuti, 2008, garuti et al., 2011). the veins vary in thickness from 10 to 30 centimetres, but giant veins of 0.5 to 1.5 metres diameter have also been observed locally. the pillow basalt shows progressively increasing spilitic alteration from the outside towards the core of the stockwork pipe, with the appearance of disseminated pyrite (garuti et al., 2011). individual veins cutting across pillow basalt may have weakly deformed, sharp contacts with the country rock, or display disrupted irregular boundaries generating an anastomosing texture in which centimetre to decimetre sized fragments of strongly spilitised basalt are engulfed. veins cutting across the ophiolitic breccia have irregular, diffuse boundaries derived from permeability-controlled infiltration of fluids into the country rock. here, the mineral corrensite ((mg,fe)9((si,al)8o20)(oh)10 · nh2o) has been identified as a major component of the clayey matrix of the breccia. the occurrence of corrensite possibly indicates the reaction of the original clay minerals with a hot hydrothermal solution (daoudi & pot de vin, 2002). the ophiolitic sandstone is usually barren, or weakly mineralised with infiltration of minute calcite‑epidote‑sulphide fissure filling and impregnation. epigenetic veins containing abundant datolite (cabsio4(oh)) have also been described (garuti et al., 2008, 2011; zaccarini et al., 2008). relevant mining sites, prospects and outcrops predominate in the northern block of the boccassuolo ophiolite (fig. 1b). the veins form a sub‑vertical pipe extending between 600 m, at the lower level of the due livelli mine (site nr. 1), up to the elevation of about 750 m, above the labirintica mine (site nr. 5). between these two localities, mineralised veins had been intercepted by mining works at the altitudes of 654 m (lumaca prospect, site nr. 2), 663 m (allagata mine, site nr. 3), and 673 m (dolicopoda‑pipistrello prospects, site nr. 4). furthermore, a single vein up to 1 m thick (filone 101) is exposed between sites nr. 2 and 3 (garuti et al., 2011). in the southern block, a few veins crop out in small mining prospects (trenches and galleries) close to the lame locality (site nr. 7, 1031‑1060 m) northeast of the cinghio del corvo peak (1079 m). two previously unknown sulphide occurrences have been recently brought to light by natural erosion (filone omar, site nr. 6, 880 m), or dug out during quarrying work for basaltic aggregate (cinghio del corvo quarry, site nr. 8, 874 m). in both the northern and southern blocks, the stockwork mineralisation disappears upwards, apparently not tectonically interrupted, but topped by new pillow lava and basalt breccia debris flows (garuti et al., 2011). major sulphide minerals are pyrite (±accessory pyrrhotite), along with variable amounts of chalcopyrite, sphalerite and galena, minutely disseminated in a quartz‑carbonate‑ chlorite gangue (bertolani, 1953; zaccarini & garuti, 2008). based on the pb‑ag‑au‑zn‑cu distribution pattern, three major types of veins have been identified (garuti et al., 2011): type 1 is characterised by high cu (2.09 – 5.94 wt%), zn (1.92 – 4.85 wt%), ag (2.9 – 7.28 ppm), au (11‑17 ppb), and pb below the detection limit of 0.3 ppm. type 2 is the most common sulphide mineralisation, with variable concentrations of cu (20 ppm – 3.89 wt%), zn (0.01 – 2.31 wt%), ag (2.0 – 13 ppm) and au (2.0‑13 ppb), but characterised by a moderate pb content (3.43 – 117 ppm). type 3 is rare, and shows low cu (0.02 – 0.6 wt%), zn (0.01 – 0.44 wt%), ag (0.63 – 1.08 ppm) and au (4.1‑6.5 ppb), but relatively high pb (906 – 1532 ppb) which accounts for the abundant galena in the sulphide mineral assemblage. the concentration of sulphide increases from a lowgrade (1.06‑2.09 wt% sulphur) to medium‑grade (3.0‑6.2 wt% sulphur) in type 2 and 3 veins and relatively high‑grade (8.73‑12.3 wt% sulphur) in type 1 and 2 veins. the appearance of distinctive pb anomalies in the veins of boccassuolo, compared with other stockwork vein deposits in the northern apennine ophiolites, has been interpreted as evidence of their emplacement in a transition zone from the ligurian mid-oceanic-ridge to the adria continental margin (garuti et al., 2011). 5. sampling and analytical techniques a total of 104 samples were collected from abandoned galleries, dumps (in front of the galleries) and natural outcrops of 8 different levels (sites no. 1‑8, see above) of the boccassuolo ophiolite (fig. 1b). thirty-three representative samples of the sulphide mineralisation were selected for the fluid inclusion study (table 1), in part they are the same samples analysed in previous works (zaccarini & garuti, 2008, garuti et al., 2009, 2011), in part they are samples studied in detail only during this investigation (therefore they were not classified into vein types by garuti et al. 2011). petrography of the studied samples was carried out with a zeiss axioplan microscope. the work was completed with observations in ir light, using a hamatsu c2400 camera (spectral response from 400 nm to 1800 nm) system mounted on an olympus bh2 type microscope. fluid inclusion petrography and a microthermometric study were carried out on 80‑100 μm thick, double polished sections of the stockwork veins, using a linkam ft‑ir 600 type heating freezing stage mounted on an olympus bx-51 type polarizing microscope providing 1000x magnification. the precision of the microthermometric measurements was ±0.1 oc below 0 oc, and ±1 oc above it. the calibration of the instrument was made by analysis of co2 and pure water synthetic fluid kiss: fluid inclusion study of the boccassuolo vms-related stockwork deposit (northern apennine ophiolites, italy) geologia croatica 289 ta bl e 1: l is t o f t he st ud ie d sa m pl es . si te n r. m in e ve in ty pe * sa m pl e nr . d es cr ip tio n m in er al c om po si tio n           py rit e py rr ho tit e ch al co py rit e sp ha le rit e g al en a q ua rt z ca lc ite ch lo rit e se ric ite ep id ot e 1 m in ie ra d ei d ue l iv el li bo 53 m in er al is ed v ei n x   x x   x x x x   1 bo 55 m in er al is ed v ei n x   x x   x x   x   1 bo 56 po or ly m in er al is ed v ei n x   x x   x x   x   23 bo 10 1 m in er al is ed v ei n x         x     x   3 g al le ria a lla ga ta bo 42 m in er al is ed v ei n x   x x   x     x   3 bo 78 m in er al is ed v ei n x   x x   x     x   4 g al le ria d ol ic op od a bo 9 m in er al is ed v ei n x   x x   x x x x   4 ty pe 2 bo 38 m in er al is ed v ei n x   x x   x x x x   4 ty pe 1 bo 33 m in er al is ed v ei n x x x x   x x x x   4 g al le ria d el p ip is tr el lo ty pe 2 bo 28 m in er al is ed v ei n x   x x   x x x x   4 bo 65 m in er al is ed v ei n x   x x   x x x x   5 g al le ria l ab iri nt ic a bo 1 m in er al is ed v ei n x   x x   x x x x   5 bo 2 m in er al is ed v ei n x x x x   x x   x   5 ty pe 1 bo 3 m in er al is ed v ei n x   x x   x x x x   5 ty pe 1 bo 5 m in er al is ed v ei n x   x x   x x x x   5 ty pe 1 bo 6 m in er al is ed v ei n x   x x   x   x x   6 fi lo ne o m ar bo 95 ba nd ed v ei n in b as al t b re cc ia x   x x   x x   x   6 bo 96 ba nd ed v ei n in b as al t b re cc ia x   x x   x x   x   6 ty pe 2 bo 97 ve in in b as al t b re cc ia x   x x   x x x x   6 ty pe 2 bo 98 ve in in b as al t b re cc ia x x x x   x x x x   6 bo 99 ve in in b as al t b re cc ia x   x x   x x   x   6 bo 10 0 ve in in b as al t b re cc ia x   x x   x x   x   7 le l am e ty pe 2 bo 35 m in er al is ed v ei n x   x x   x   x x   7 ty pe 2 bo 36 m in er al is ed v ei n x   x x   x   x x   8 ca va d ei c in gh i ty pe 2 bo 11 m in er al is ed v ei n x   x x   x x x x   8 ty pe 2 bo 12 m in er al is ed v ei n x   x x   x x x x   8 ty pe 2 bo 14 m in er al is ed v ei n x   x x   x x x x   8 bo 18 m in er al is ed v ei n x   x x   x x x x x 8 bo 90 m in er al is ed v ei n x   x x x x x x x   8 ty pe 3 bo 91 m in er al is ed v ei n x   x x x x x x x   8 ty pe 3 bo 92 m in er al is ed v ei n x   x x x x x x x   8 ty pe 3 bo 93 m in er al is ed v ei n x   x x x x x x x   8 bo 94 m in er al is ed v ei n x   x x x x x x x   to ta l n um be r o f s am pl es : 3 3 *: v ei n ty pe s a cc or di ng to g a ru ti e t a l. 20 11 , a pp lie d on ly fo r s am pl es , w hi ch w er e cl as si fie d in th at st ud y. geologia croatica 68/3geologia croatica 290 inclusions. these analyses were carried out at the eötvös loránd university, department of mineralogy. raman microanalysis of fluid inclusions in quartz and calcite was completed at the eötvös loránd university, faculty of science, research instrument core facility, using a horiba yvon jobin labram hr 800 edge filter based confocal dispersive raman spectrometer, 800 mm focal length, coupled with an olympus bxfm type microscope. during the measurements, 532 nm emission of a frequency doubled nd:yag laser, 600 grooves/mm grating, 50 μm confocal aperture and 50x and 100x long working distance objective were used. for some measurements, the linkam ftir 600 microthermometric stage was mounted to the spectrometer and analyses were performed at different temperatures from ‑50 °c to +355°c. interpretation of the microthermometric and raman spectroscopic data was carried out using the methods of guillaume et al. (2003), duan & mao (2006) and sun et al. (2010) and using peakfit v. 4.12. software by seasolve software inc. for salinity calculations (sun et al., 2010), the same treatment was performed in each case: the baselines were corrected by the linear method, the spectra were fitted with two gaussian functions (fitting parameter r2=0.995-0.997). the effects of measurement conditions and data fitting procedure were eliminated by calculating the difference between the solution and pure water. as the base of the calculations is the good quality raman spectra of the aqueous liquid phase of the inclusions, only those are applied in the study, which are characterised by >10µm size, stationary gas bubble and are occurring deep in the samples. chlorite thermometry calculations are based on the chlorite composition database of zaccarini & garuti (2008), and new electron microprobe analyses performed at the eugen stumpfl microprobe laboratory (university of leoben) using a jeol superprobe jxa‑8200, operated at 15 kv accelerating voltage, 10 na beam current, ~1 µm beam diameter, and counting times of 20 and 10 seconds for peak and backgrounds, respectively. the x‑ray kα lines for si, mg, al, ti, cr, ca, na, k, mn, fe, and natural silicates and chromium spinel as standards were used for the analysis of chlorite. the method of chatelineau & izquierdo (1988) with an uncertainty of about 20°c was used to calculate the formation temperature of the chlorite, as the measured al(iv) and xfe amounts of the individual crystals fitted into the criteria of that method. 6. characterisation of the hydrothermal processes 6.1. petrography of the veins the studied veins occur in strongly altered basalt. the original variolitic texture of the basalt is hardly traceable; the rock is almost completely altered to clay minerals, chlorite and fine grained quartz. it is commonly cross‑cut by <1 mm thick quartz veins. the basalt‑vein contact is sharp and contains –besides a few altered glassy basalt clasts– the same minerals, as the other parts of the vein. the studied veins were partly classified by garuti et al. (2011) into vein types 1, 2, and 3, but samples without this earlier classification were also studied (table 1). however, based on the available results (garuti et al., 2011), the northern block of the boccassuolo ophiolite (sites nr. 1-5) contains only types 1 and 2, while the southern block (sites nr. 6‑8) contains only types 2 and 3 veins. according to the observations, no significant difference in the occurring gangue and ore minerals was observed between vein types 1, 2 and the unclassified samples, although the amounts of the ore minerals may vary. in contrast, vein type 3 differs notably, since galena occurs only in these veins. based on these, a summarising description is presented here, and the occurrence of the different gangue and ore minerals at the various localities is shown in table 1. quartz is the most common gangue mineral found in the veins. generally, it occurs in all 3 vein types in 3 generations, corresponding to the sequence of crystallisation events (fig. 2a); quartz 1 is the oldest, while quartz 3 is the youngest. quartz 1 (qtz1) is characterised by 1-10 mm euhedral and subhedral, commonly growth zoned crystals with a spongy core. they frequently show a comb structure resulting from open‑space filling from the vein walls inward. quartz 2 (qtz2) is typically 0.1-1 mm subhedral, barely transparent quartz, while quartz 3 (qtz3) is commonly <0.05 mm in size and forms anhedral crystals. qtz3 may form thin veinlets, with/without carbonate and sulphides, cross-cutting or sometimes even brecciating the earlier quartz grains (fig. 2b). in general, all three generations are observed at every locality, though their relative amounts may be different. the only exception is site nr. 6, where only qtz2 and qtz3 were observed. sericite occurs commonly as <10 μm sized anhedral grains among the quartz crystals and also as solid inclusions within them. carbonate and chlorite consist of 0.1-1 mm sized anhedral grains (fig. 2a, c, d), occurring rarely cogenetically with, most commonly epigenetically to the quartz crystals. sulphide minerals occur disseminated interstitially or as solid inclusions in both quartz generations, usually showing a banded distribution, symmetrical around the centre of the vein. therefore, early and late sulphides were also distinguished. except for samples from sites nr. 2‑3, where only pyrite occurs, pyrite is commonly accompanied by chalcopyrite, sphalerite and rarely galena and pyrrhotite, forming up to 5‑50 area% of the ore. the pyrite may form eu-, suband anhedral crystals up to 5 mm in size, and can be one of the most common ore minerals (fig. 2e, f). none of the crystals are transparent in ir light. chalcopyrite is the second most common ore mineral, varying between 5‑50 area% of the ore. it forms up to 1 mm sized anhedral crystals (fig. 2f, g). sphalerite occurs at almost each studied locality, forming anhedral grains up to 2 mm in size. its amount varies between 1‑10 area% of the ore. grains with signs of „chalcopyrite disease” are common (fig. 2e, h), though some crystals are lacking this feature. the formers are not transparent in ir light, while the kiss: fluid inclusion study of the boccassuolo vms-related stockwork deposit (northern apennine ophiolites, italy) geologia croatica 291 figure 2: typical textures of the gangue and ore minerals under polarizing microscope. a: euhedral and subhedral coarse grained qtz1, the remaining space is filled by qtz2, qtz3 and calcite (cal) (site nr. 8, 1n). b: the coarse grained qtz1 is brecciated by qtz3 (site nr. 2-3, +n). c: chlorite (chl) fills up the space among the crystals of qtz2 (site nr. 3, 1n). d: strongly altered basalt with qtz2, transparent sphalerite (sp) and late calcite (site nr. 6, 1n) e: pyrrhotite (po) inclusions in early pyrite (py), and later sphalerite (sp) with chalcopyrite (ccp) disease (site nr. 4, 1n). f: chalcopyrite consuming the early pyrite (site nr. 4, 1n). g: later chalcopyrite veins cutting the earlier sphalerite (site nr. 6, 1n). h: chalcopyrite disease in sphalerite (site nr. 4, 1n). geologia croatica 68/3geologia croatica 292 latter ones are transparent even in vis (fig. 2d). pyrrhotite occurs only as <0.05 mm inclusions within the pyrite (fig. 2e). the amount of this mineral is always <1 area% of the ore. galena forms anhedral grains up to 0.3 mm, forming up to 5‑10 area% of the ore in the type 3 veins of site nr. 8. based on the textural features, a generalised mineral precipitation sequence is postulated (fig. 3). 6.2. fluid inclusion petrography fluid inclusions were observed at all sites (nr. 1‑8), vein types (1‑3) and quartz generations (qtz1, qtz2 and qtz3), in both the calcite and sphalerite. as no significant petrographic difference was observed among the fluid inclusions of vein types 1‑ 3, or between the different sites, a summary description is presented here. all the studied minerals were barely transparent, due to the extremely high amount of secondary fluid inclusion planes, which created difficulties during the petrographic study. qtz1 and qtz2 contain rare, generally 4‑7 μm sized, rectangular shaped, two‑phase (liquid, l and vapour, v) fluid inclusions of primary origin, either in the growth zones or in the spongy core of the crystals (fig. 4a, c). the phase ratio is fairly constant (10‑20 area% v and 90‑80 area% l), suggesting a homogenous entrapment from a homogenous parent fluid. the inclusions rarely reach 15‑20 μm in size and/or contain accidentally trapped, irregularly shaped solid phase(s) (s) (fig. 4d). identification of the primary inclusions was hindered by the high amount of secondary inclusions, of which several generations were observed. one of these is characterised by similar features, like the primary inclusions of qtz3, while other generations of single‑phase (l) and two‑phase (l+v, v <5 area%), 1‑25 μm sized inclusions with irregular or rounded shape also occur. qtz3 contains rarely 4‑20 μm sized, rectangularly shaped, single‑ (l) or two‑phase (l+v) fluid inclusions of primary origin, occurring far from the secondary planes (fig. 4e). the phase ratio is fairly constant (5‑10 area% v and 95‑ 90 area% l) in the two‑phase inclusions, suggesting a homogenous entrapment from a homogenous parent fluid. the calcite contains rarely 4‑20 μm sized, negative crystal shaped, single‑ (l) or two‑phase (l+v) fluid inclusions of primary origin, occurring far from the secondary planes (fig. 4b). the phase ratio is fairly constant (5‑10 area% v and 95‑90 area% l) in the two‑phase inclusions, suggesting a homogenous entrapment from a homogenous parent fluid. extremely high numbers amounts of secondary planes occur, containing commonly one-phase (l) inclusions, but twophase (l+v, v<5 area%) inclusions are also observed. the one‑phase (l) primary inclusions of qtz3 and the calcite may be interpreted as a phenomenon of metastable stretched liquid. this inhibits the formation of a vapour bubble during cooling and hence precludes measurement of th at t below ~65 °c (goldstein & reynolds, 1994; diamond, 2003). the sphalerite is rich in secondary planes (fig. 4h), containing one‑phase (l), rarely two‑phase (l+v, v~5 area%), rectangularly shaped inclusions of 5‑20 μm in size. in the growth zones of the crystals, solid chalcopyrite inclusions (fig. 4f, g), together with some poorly observable (due to their small size and dark outline) fluid inclusions occur. far from the secondary planes, 10‑20 μm sized, rectangular shaped, two‑phase (l + v) primary inclusions are rarely observed (fig. 4i), with a constant phase ratio (~20 area% v and ~80 area% l). despite of its scarce occurrence, based on the textural similarities with the inclusions of qtz1 and qtz2, a homogenous entrapment from a homogenous parent fluid is assumed. figure 3: the temporal series of mineral precipitation in the studied stockwork veins. kiss: fluid inclusion study of the boccassuolo vms-related stockwork deposit (northern apennine ophiolites, italy) geologia croatica 293 figure 4: typical textural features of the fluid inclusions in quartz, calcite and sphalerite. a: two-phase l+v primary fluid inclusions in the growth zones of qtz1 (site nr. 8). b: two-phase l+v primary fluid inclusions among the secondary planes of the late calcite (site nr. 8). c: two-phase l+v primary fluid inclusion in the spongy core of qtz1 (site nr. 5). d: three-phase l+v+s, accidentally trapped mineral containing fluid inclusion in qtz1 (site nr. 2-3). e: twophase l+v primary fluid inclusion in qtz3 (site nr. 1). f: chalcopyrite inclusions in the growth zone of sphalerite (site nr. 6). g: the same location under a reflected light microscope (site nr. 6, 1n). h: abundant secondary inclusion planes in transparent sphalerite (site nr. 6). i: two-phase l+v primary fluid inclusion in sphalerite (site nr. 6). 6.3. microthermometric study fluid inclusion microthermometry was carried out on the different quartz generations, as well as on calcite grains. the results were evaluated according to the different sites as well as the vein types, in order to be able to draw more precise conclusions. analyses were carried out on well defined fluid inclusion assemblages, only where the petrographic association of the inclusions was unambiguous and they represented the original trapped fluid. measurements on qtz3 were often geologia croatica 68/3geologia croatica 294 impossible due to small crystal size and low transparency, therefore only a few data are available. metastability often caused failure to observe the final melting temperatures, resulting in some cases incomplete data sets. attempts to obtain measurements through heating were performed on sphalerite crystals, but due to its intensive cleavage upon heating above 150°c‑200°c, no successful measurements were documented. results of the fluid inclusion microthermometry are presented in table 2. and fig. 5ab. in some cases, a high standard deviation was observed regarding th, which may be interpreted as a result of temporal fluid evolution. this is proven by two facts. firstly, in several cases, a th increase of 10‑15°c (at sites nr. 1 and 5) and th decrease of 10‑30°c (at sites nr. 4 and 8) were observed from the core to the rim of the same quartz crystal. secondly, measurement of diffe‑ rent sized inclusions in the same growth zone resulted in consistent th values (maximum scattering was 7°c). this latter observation, in line with the experience of bodnar (2003) (the smaller the size and higher the gas content characterising the inclusion, the higher the pressure that is needed to begin reequilibration), strengthens the lack of reequilibration processes. eutectic temperatures were determined in only a few cases, between ‑20.9°c and ‑22.4°c. thus, nacl‑containing aqueous solution was applied for modelling the system. however, salinities were not calculated from the observed final melting temperature data (table 2.), because the last solid to melt is ch4 clathrate, as discussed in the following section. due to the small size of the inclusions, it was generally only possible to observe the final melting, i.e. it was not possible to distinguish iceand clathrate melting. a few available, uncertain data of ice melting scatter between tm(ice)=(‑5.5)°c and (‑5.9)°c, corresponding to a salinity of approx. 6.5 nacl equiv. wt%. 6.4. raman spectroscopy analyses raman spectroscopy analyses were carried out to examine the gas content and the accidentally trapped solid phases as well as to calculate salinity and the amount of gas in the quartz and calcite hosted primary fluid inclusions. all the analysed accidentally trapped minerals were found to be sericite (muscovite). in the gas phase, the presence of methane was proven at sites nr. 1, 2‑3, 4, 5, 6 and 8, in the primary inclusions of both quartz generations as well as in the calcite and no other gas phases were observed. the table 2: fluid inclusion microthermometry studies in quartz and calcite and chlorite thermometry calculations. site nr. vein type* mineral number of measurements average th (lv-l) (°c) st.dev. th (°c) average tm (cla) (°c) st. dev. tm (cla) (°c) average formation t (°c) st.dev formation t (°c) 1 – quartz 1. 11 308 38 –1.3 0.2 – – 1 – quartz 2. 10 314 24 –1.3 0.2 – – 1 – quartz 3. 5 70 8 –0.5 – – – 1 – chlorite 5 – – – – 140 21 2–3 – quartz 1. 22 89 16 –0.6 – – – 2–3 – quartz 2. 10 103 24 – – – – 4 type 1 quartz 1. 8 295 22 –1.5 0.1 – – 4 type 1 quartz 2. 12 235 29 –1.4 0.2 – – 4 type 1 calcite 9 79 6 –0.5 0.1 – – 4 type 1 chlorite 5 – – – – 209 14 5 type 1 quartz 1. 14 289 37 –1.4 0.2 – – 5 type 1 quartz 2. 9 302 20 –1.6 0.1 – – 5 type 1 quartz 3. 6 74 6 –1.2 0.4 – – 5 type 1 chlorite 12 – – – – 210 23 6 type 2 quartz 2. 11 303 21 –0.6 0.2 – – 6 type 2 quartz 3. 2 152 – – – – – 6 type 2 calcite 12 89 40 –0.8 0.5 – – 8 type 2 quartz 1. 13 233 38 –0.7 0.3 – – 8 type 2 quartz 2. 6 163 30 –0.6 0.3 – – 8 type 2 quartz 3. 4 111 2 –0.5 0.2 – – 8 type 2 calcite 14 81 13 –0.4 0.2 – – 8 type 2 chlorite 1. 3 – – – – 259 16 8 type 2 chlorite 2. 4 – – – – 159 25 8 type 3 quartz 1. 6 154 3 – – – – 8 type 3 chlorite 8 – – – – 168 25 total number of measurements: 221 *: vein types according to garuti et al. 2011, applied only for samples, which were classified in that study. kiss: fluid inclusion study of the boccassuolo vms-related stockwork deposit (northern apennine ophiolites, italy) geologia croatica 295 occurrence of methane clathrate upon cooling was also confirmed (fig. 6a, b, d). salinity calculations were performed based on the method of sun et al. (2010), on fluid inclusions of randomly oriented quartz crystals from sites nr. 1, 2‑3, 5. and 8. the calculated salinities are between 6.2 and 11.4 nacl equiv. wt%, as presented in table 3. the amount of methane was calculated using the method of guillaume et al. (2003), on fluid inclusions of qtz1 from site nr. 8. this calculation is based on the raman spectra of the homogenised liquid (fig. 6c), measured only on large fluid inclusions in order to eliminate any expansion effect occurring during heating. the results of the calculations are presented in table 3, together with the calculated homogenisation pressure (duan & mao, 2006). taking into consideration the homogenous nature of the parent fluid, this data corresponds to the minimum formation pressure. 6.5. chlorite thermometry calculations chlorite analyses from the database of zaccarini & garuti (2008) were used to calculate the formation temperature of the chlorite crystals (see the representative analyses in table 4.). chlorite compositions measured in the same samples used for the fluid inclusion study to enable efficient comparison of the results. instead of using the thermometry method of kranidiotis & maclean (1987), suggested by zaccarini & garuti (2008), the method of cathelineau & izquierdo (1988) was used here, as the al (iv) and xfe values of the measured data fitted into the criteria of the latter method. the calculated formation temperatures are tformation=122‑276°c, the details are shown in table 2. and in fig. 5c. 7. discussion 7.1. ptx conditions of the hydrothermal system several extensive studies and reviews have been published about submarine hydrothermal systems, summarising the ta bl e 3: s al in ity a nd m et ha ne c on te nt * of fl ui d in cl us io ns b as ed o n th e ra m an sp ec tr os co py a na ly se s. si te n r. ve in ty pe ** m in er al n um be r o f m ea su re m en ts av er ag e th (l vl) (° c) st .d ev . t h (°c ) av er ag e sa lin ity (n ac l e qu iv .w t% ) st .d ev . s al in ity (n ac l e qu iv .w t% ) av er ag e m et ha ne co nt en t ( m ol /k g) st .d ev . m et ha ne co nt en t ( m ol /k g) m in /m ax m in im um fo rm at io n pr es su re (m pa ) 1 – q ua rt z 1. 5 29 5 19 9. 00 0. 62 – – – 2– 3 – q ua rt z 1. 4 88 7 10 .4 9 0. 57 – – – 5 ty pe 1 q ua rt z 1. 5 25 0 14 10 .1 9 1. 20 – – – 8 ty pe 2 q ua rt z 1. 6 20 2 18 8. 06 1. 45 0. 28 0. 06 31 .2 -3 8. 5 *: th e oc cu rr en ce o f m et ha ne w as p ro ve n at si te s n r. 1, 2 -3 , 4 , 5 , 6 a nd 8 ., b ut th e ex ac t m et ha ne c on te nt w as c al cu la te d on ly w he re p ro pe r i nc lu si on s w er e fo un d. ** : v ei n ty pe s a cc or di ng to g a ru ti e t a l. 20 11 , a pp lie d on ly fo r s am pl es , w hi ch w er e cl as si fie d in th at st ud y. ta bl e 4: s el ec te d ch lo rit e an al ys es fr om th e da ta ba se o f z ac ca ri n i a nd g a ru ti (2 00 8) , r ep re se nt in g th e di ffe re nt v ei n ty pe s a nd lo ca lit ie s. m as s% ca tio n nu m be rs (c al cu la te d fo r 1 4 o ) si te n r. ve in ty pe * m in er al si o 2 ti o 2 al 2o 3 cr 2o 3 fe o m no m go ca o n ao k 2 o to ta l si al (i v) al (v i) ti cr fe m n m g ca k n a to ta l v iv ac an cy xf e t (°c ) * * 1 – ch lo rit e 30 .8 8 0. 00 12 .7 2 0. 00 14 .7 8 0. 62 22 .3 7 0. 31 0. 05 0. 04 82 .0 4 3. 30 0. 70 0. 91 0. 00 0. 00 1. 32 0. 06 3. 57 0. 04 0. 01 0. 01 5. 90 0. 10 0. 27 16 2 4 ty pe 1 ch lo rit e 29 .6 1 0. 00 14 .3 5 0. 00 16 .3 5 0. 44 21 .3 5 0. 04 0. 00 0. 00 82 .1 4 3. 18 0. 82 0. 99 0. 00 0. 00 1. 47 0. 04 3. 41 0. 00 0. 00 0. 00 5. 92 0. 08 0. 30 20 3 5 ty pe 1 ch lo rit e 31 .8 6 0. 01 17 .0 5 0. 04 11 .0 2 0. 28 25 .0 5 0. 33 0. 03 0. 01 85 .6 8 3. 16 0. 84 1. 15 0. 00 0. 00 0. 91 0. 02 3. 70 0. 04 0. 00 0. 01 5. 84 0. 16 0. 20 20 8 8 ty pe 2 ch lo rit e 1. 30 .7 0 0. 00 17 .7 1 0. 06 17 .4 8 0. 54 23 .1 3 0. 24 0. 02 0. 01 89 .8 7 3. 01 0. 99 1. 06 0. 00 0. 00 1. 43 0. 04 3. 39 0. 02 0. 00 0. 00 5. 96 0. 04 0. 29 25 5 8 ty pe 2 ch lo rit e 2. 30 .7 1 0. 02 12 .2 4 0. 01 19 .5 4 0. 40 18 .1 0 0. 41 0. 08 0. 01 81 .5 3 3. 38 0. 62 0. 96 0. 00 0. 00 1. 80 0. 04 2. 97 0. 05 0. 00 0. 02 5. 84 0. 16 0. 37 13 9 8 ty pe 3 ch lo rit e 31 .8 0 0. 02 15 .4 8 0. 00 15 .4 0 0. 30 21 .3 4 0. 19 0. 02 0. 00 84 .5 4 3. 27 0. 73 1. 15 0. 00 0. 00 1. 32 0. 03 3. 27 0. 02 0. 00 0. 00 5. 79 0. 21 0. 29 17 3 *: ve in ty pe s a cc or di ng to g a ru ti e t a l. 20 11 , a pp lie d on ly fo r s am pl es , w hi ch w er e cl as si fie d in th at st ud y ** : f or m at io n te m pe ra tu re c al cu la tio n ba se d on th e m et ho d of c at h el in ea u & iz q u ie rd o (1 98 8) geologia croatica 68/3geologia croatica 296 figure 5: minimum formation temperatures of quartz and calcite, as well as the formation temperature of chlorite at the different localities. a: a homogenisation temperature distribution diagram of quartz and calcite from the southern block of boccassuolo (sites 6 and 8). b: homogenisation temperature distribution diagram of quartz and calcite from the northern block of boccassuolo (sites 1-5). c: formation temperature of chlorite from different sites, based on chlorite thermometry calculations. a) b) c) kiss: fluid inclusion study of the boccassuolo vms-related stockwork deposit (northern apennine ophiolites, italy) geologia croatica 297 figure 6: results of the raman spectroscopy analyses. a: raman spectra of methane found in the gas phase of a primary fluid inclusion at lab temperature (25°c) (site nr. 8, qtz1). b: methane clathrate occurs together with ice, upon cooling, at -20°c (site nr. 1, qtz1). c: homogenisation experiment in a primary fluid inclusion. upon heating, dissolved methane occurs in the liquid phase. methane content calculations were performed at 20°c above the homogenisation temperature (245°c) (site nr. 8, qtz1). d: raman spectra of the accidentally trapped solid phase in a primary fluid inclusion at lab temperature (25°c). background quartz was subtracted, in order to be able to identify muscovite. reference muscovite from the ruff data base (downs, 2006) is also plotted (site nr. 2-3, qtz1). a) b) c) geologia croatica 68/3geologia croatica 298 concepts on the sources, development and run of those processes (see e.g. rona, 1984; herzig & hannington, 1995; wilkinson, 2001; foustoukos & seyfried, 2007; pirajno, 2009 and the references cited therein). although many studies are available about both modern and ancient spreading ridge systems, significantly more results are published from other geodynamic environments (e.g. kuroko‑type systems, iberian pyrite belt, precambrian systems). wilkinson (2001) and pirajno (2009) agreed, however, that the concepts and knowledge about the kuroko‑type hydrothermal systems may be extended to other vms deposits, therefore in the present discussion results and interpretations from different geodynamic environments are used. 7.2. composition of the hydrothermal fluid wilkinson (2001) has reported a typical salinity range of 1‑8.4 nacl equiv. wt% for the hydrothermal fluids of the kuroko‑type deposits, similar to the 4±1.6 nacl equiv. wt% result of nehlig (1991) from ophiolites and modern analogues. other works have reported higher salinities up to 24 nacl equiv. wt% in ancient vms systems (e.g. china, zengqian et al., 2008, the iberian pyrite belt, tornos, 2006). moreover, the occurrence of even halite‑bearing fluid inclusions were also documented both at precambrian (salinities of 38.2 ± 1.9 nacl equiv wt%, ioannou et al., 2007) and phanerozoic locations (salinities up to 52 nacl equiv. wt%, nehlig, 1991 and juteau et al., 2000). a recent compilation by bodnar et al. (2014) has confirmed a typical salinity range of 2‑6 nacl equiv. wt% for felsic, mafic and bimodal volcanism hosted vms deposits, though higher salinity inclusions (99% of the data are within the range of 0‑21 nacl equiv. wt%) were also reported. modification of the seawater may cause high salinity variations, the processes may involve fluid‑rock interaction, mixing with seawater, phase separation (i.e., boiling), leaching of evaporites in the host sedimentary rocks, and/or mixing with magmatic volatiles, according to nehlig (1991), scott (1997), wilkinson (2001), foustoukos & seyfried (2007), pirajno (2009), bodnar et al. (2014) and references cited therein. in the case of boccassuolo, the calculated (based on raman spectra of the inclusions’ fluid) salinities are between 6.2 and 11.4 nacl equiv. wt% in the different vein types. comparison of these data with the few available microthermometry based values (approx. 6.5 nacl equiv. wt%), as well as cross-checks with other raman spectra based methods (mernagh & wilde, 1989) supports the validity of this latter approach, although the results still have to be handled with caution, knowing the uncertainties of the raman spectra based salinity calculations (see e.g. baumgartner & bakker, 2009). the th vs. salinity diagram shows a slight decrease of salinity with decreasing temperature (fig. 7.), which can be explained by more intense mixing of hydrothermal fluids with seawater towards the top of the system. the determined salinities indicate a modified seawater origin. as petrographic evidence of phase separation (coexisting liquid and vapour rich inclusions) was not observed, together with the fact that the th vs. salinity diagram does not suggest mixing between two end‑members, this process can be excluded as a possible source of seawater modification. evaporites are not known in the host rock series. therefore the two possible explanations would be the fluid‑rock interaction and/or addition of magmatic volatiles. similar salinity ranges were interpreted -with the help of o and h isotopes‑ as a result of modified seawater and magmatic fluid mixing at several iberian pyrite belt localities (tornos, 2006), but simple fluid‑rock interaction may also cause such elevated values (nehlig, 1991). therefore both options could be reasonable explanations, and an unequivocal decision cannot be made based on the salinity values. the presence of methane (average 0.28 mol/kg) may reveal further details. though co2 is the most common volatile component in vms systems (pirajno, 2009), it was not observed in the studied fluid inclusions of boccassuolo. instead, a remarkable amount of methane occurred at both sites. methane may form during biotic or abiotic (i.e., without involving organic matter) processes. ch4 degassing (i.e. magmatic volatile) can be intense, if serpentinised peridotite is present, but methane can also occur in the system if seawater co2 is transformed to ch4 after passing through the recharge zone, or it may occur as an indirect by-product of hydrothermal alteration of mafic rocks or graphitic, carbonaceous wall rocks (rona, 1984, zengqian et al., 2008, pirajno, 2009, etiope & schoel, 2014). in the studied area, interaction between the volcanic succession and sedimentary rocks is evidenced by the formation of corrensite (garuti et al., 2011). additionally, serpentinised peridotite occurs also in the nearby ophiolites. thus, an unequivocal decision cannot be made, a future detailed stable isotope study may help in answering this question. the rather similar compositional features of the studied primary inclusions suggest that the different vein types (defined by garuti et al., 2011), all quartz generations and late calcite formed from the same evolved solution as part of the same hydrothermal process. figure 7: homogenisation temperature (based on fluid inclusion microthermometry) vs. salinity (based on raman spectroscopy) diagram of the quartz samples from boccassuolo (data from the late fluid circulation event of site 2-3 are not presented). kiss: fluid inclusion study of the boccassuolo vms-related stockwork deposit (northern apennine ophiolites, italy) geologia croatica 299 7.3. pressure of the hydrothermal fluid the typical water column in similar systems is 2.5 km in depth, which corresponds to a pressure of 25 mpa. in gene ral, the depth of the stockwork zone is 100‑300 m, up to 1‑2 km below the seafloor, but typically remains within 1 km. besides hydrostatic pressures, lithostatic or near-lithostatic pressures may also occur, if an independent and/or isolated convection cell forms at depth. thus the characteristic pressure of the stringer zone is the sum of the hydrostatic pressure of the water column and the stringer zone and – if applicable – the lithostatic pressure. generally it comprises 30‑60 mpa, but in some cases, can reach 90 mpa, especially if self-sealing of the cracks is taken into consideration (e.g. sherlock et al., 1999; ioannou et al., 2007; pirajno, 2009; steelemacinnis, 2012 and references cited therein). in boccassuolo, the minimum formation pressure in the uppermost level of the deposit was 31.2‑38.5 mpa. conside‑ ring that the total thickness of the pillow series did not exceed 500 m (plesi et al., 2002), and calculating with a typical water column of 2.5 km, a total of 30‑44 mpa pressure can be estimated. this approximation is in good agreement with the typical stockwork-zone pressures shown above, as well as with the observed minimum formation pressures. hence no further pressure correction was performed on the obtained homogenisation temperature data. 7.4. temperature of the hydrothermal fluid in general, vms stockwork mineralisations are interpreted as the discharge zone of the seafloor vents, formed at similar, or slightly higher temperatures, than the massive sulphide mound (e.g. zengqian et al., 2008 reported <220°c to >300°c in the stringer zone and 62‑225°c in the massive sulphide body). a wider range of homogenisation temperatures (100‑400°c) was also reported previously from different stringer zones (e.g. nehlig, 1991, pirajno, 2009). bodnar et al. (2014) also discovered that the homogenisation temperature from the vms deposits are broadly consistent with the ‘reaction zone” temperatures, reaching a maximum of less than ~400°c. the results obtained from boccassuolo are in good agreement with the above mention ed facts, however, the measured homogenisation temperatures can be divided into three groups, indicating slightly different fluid evolution paths (fig. 8). the typical minimum formation temperatures at sites 1, 5 and 6 are 260‑340°c. there the first two quartz generations are characterised by similar temperatures, thus a relatively consistent temperature environment can be concluded. the rather wide range can be the result of sampling from different parts of the same block, as within a single sample, the differences were always within 15°c. the typical minimum formation temperatures at sites 4 and 8 are 150‑290°c. there the first quartz generation yielded higher homogenisation temperatures than the second one. at these localities, relatively rapid cooling is concluded, emphasized by the observable temperature drop of 10‑30°c within a single quartz crystal, from core to rim. at both localities, a minimum formation temperature range of 60‑130°c (generally in the third quartz generation and in calcite, but at sites 2, and 3 in each quartz generation) was also recorded. this can be interpreted as a low-temperature, later fluid circulation event, which belongs to the same, evolving hydrothermal process (see above). in contrast to the fluid inclusion data, which are in good agreement with other vms deposits, chlorite thermometry yielded slightly different results. zaccarini & garuti (2008) published a formation temperature range of 80‑360°c for stockwork chlorites of the northern apennines vms deposits, while in the case of boccassuolo, only 122‑276°c were observed (fig. 5c). both are in contrast with e.g. the iberian pyrite belt results of 320‑400°c by inverno et al. (2008). however, in the studied case, the thermometry results support the petrographic observations. it is proven that chlorite formed only rarely cogenetically with the highest temperature first quartz generation (see e.g. the results from site 8), but it precipitated mostly after or simultaneously with the second quartz generation (see e.g. the results from site 5). thus it formed generally during the cooling of the system, filling the temperature gap between the high temperature quartz and the late fluid circulation event. therefore, an additional step in the hydrothermal process is recognised with the help of this method. in contrast to the cautions against the use of this thermometer (see e.g. de caritat et al. 1993; jiang et al. 1994; essene & peacor, 1995), our observations confirm the use and validity of this method in the studied environment (similarly to the results reported by kiss et al., 2012, from a hungarian jurassic basaltic suite). 7.5. spatial and temporal evolution of the hydrothermal system 7.5.1. spatial distribution the studied sites at boccassuolo represent different levels of that ophiolitic sequence (611‑874 m a.s.l.), although it is not necessary, that they were in a similar order upon their figure 8: schematic illustration of the typical fluid evolution paths (time vs. temperature) observed at sites 1, 4, 5, 6 and 8. note, that relatively consistent temperature conditions were common at sites 1, 5 and 6, while a more rapid cooling was observed at sites 4 and 8. however, a later, low temperature event was common at every studied locality. geologia croatica 68/3geologia croatica 300 formation. while there is a known fault zone between sites 1‑5 (northern block) and 6‑8 (southern block), there is also the possibility of even smaller, so far unknown tectonic zones formed due to the obduction process (see also the dipping of the sequence). therefore, the original structure of the stockwork zone is barely traceable and interpretation of the data according to the different sites is reasonable. the observed ore and gangue minerals in the boccassuolo vms stockwork mineralisation (see e.g. the scarce occurrence of pyrrhotite and the common sericite, the latter also as an accidentally trapped solid phase in the fluid inclusions) have shown that the studied sites formed in distal locations, in relation to the centre of the fluid flow (see e.g. franklin et al. 1981; lydon, 1984; herzig & hannington, 1995; barrie & hannington, 1999; pirajno, 2009). numerical modelling of steele-macinnis et al. (2012) has revealed that the temperature along the stockwork zone is rather constant in the centre of the fluid flow, but decreases rapidly towards the distal parts. thus significant vertical temperature zonation is not expected, but a horizontal one is presumed, explaining the presence of the three homogenisation temperature groups discussed above. sites 1, 5 and 6, where no significant cooling was observed (fig. 8.), were most probably located in the more central parts of the fluid flow, but still not in the core (see the slight temperature change and the sericite content). sites 4 and 8, with more intense cooling (fig. 8.), formed at a more distal location, while sites 2‑3, where only low‑temperature processes occurred, formed even farther away. this idea is also supported by the mgo content of the chlorite crystals: 21.75‑27.20 wt% was observed at sites 1 and 5 (more central) and 14.86‑ 24.64 wt% at sites 4 and 8 (more distal). according to urabe et al. (1983), higher concentration of mgo occurs in the alteration product chlorite close to the central parts of the system. thus, the role of later tectonic movements is also indicated, bringing the more and less distal parts close to each other. however, the slightly lower temperatures and salinities observed in the southern block (caused by the more intense hydrothermal fluid‑seawater mixing) reveal that this now higher altitude block was also originally located in a higher position in the sequence. 7.5.2. temporal evolution all the observations shown above reveal a temporal evolution in the hydrothermal system (fig. 8.). quartz formed in three successive generations, while chlorite formed cogenetically and epigenetically to quartz. sphalerite most likely formed in the early stages of the hydrothermal activity, probably at a slightly lower temperature than the later chalcopyrite. chalcopyrite formed probably at a slightly higher temperature, replacing the earlier minerals (see the slight th increase in the more central sites from qtz1 to qtz2 (fig. 8.), as well as within a single qtz1 crystal). an excellent indicator for this process is the occurrence of chalcopyrite-disease in the early sphalerite, which is caused by replacement, with the reaction of the fe-s content of the sphalerite with a later cu‑rich fluid (barton & bethke, 1987). a minor amount of sphalerite formed most probably during the waning of the system, together with late chalcopyrite (no chalcopyrite disease is observable, but chalcopyrite inclusions in growth zones are found). pyrite formed during the entire process, before, simultaneously and after the cu and zn-bearing minerals. a similar evolution was also observed by ohmoto (1996) in kuroko‑type deposits. however, a slightly different process took place in the central and the distal parts, depending mostly on how rapidly the formation temperature changed (fig. 8.). this resulted in different ore mineral ratios (e.g. the amount of chalcopyrite is higher in the more central locations, and only pyrite occurs at the most distal one). this fact is proven by the chemical compositions of the veins (i.e. the occurrence of the different vein types 1, 2 and 3, defined by garuti et al. 2011); yielding up to 5.94 wt% cu in samples from site 5 (originally more central location, type 1 vein) and up to 0.4 wt% cu, but up to 1532 ppm pb in samples from site 8 (originally more distal location, type 2 and 3 veins) (garuti et al., 2011). however, each locality suffered a late, lowtemperature (<130°c) fluid circulation overprint, that still had similar characteristics (salinity, methane, sericite, fine‑ grained sulphide content), and can therefore be interpreted as a late result of the same hydrothermal process. 8. conclusions the detailed fluid inclusion, raman spectroscopy and chlorite thermometry study of sulphide mineralised quartz veins of the boccassuolo ophiolite helped to characterise the hydrothermal processes that occurred in this jurassic vmsrelated stockwork system. besides rather common sulphide minerals (pyrite, chalcopyrite, sphalerite, pyrrhotite and galena), three quartz generations as well as chlorite, sericite and late carbonate were identified. the wide range of minimum formation temperatures (370‑60°c) is most likely caus ed by the temporal evolution of the system as well as the more proximal vs. more distal position in relation to the centre of the hydrothermal fluid flow. comparison of the minimum formation temperatures defined by the fluid inclusion study and the formation temperatures based on chlorite thermometry calculations (276‑122°c) supported the petrographic observations; i.e. chlorite generally formed simultaneously and after the second quartz generation, within the temperature gap between the high temperature quartz and a late fluid circulation event. the salinity range (6.2‑11.4 nacl equiv. wt%) as well as the methane content (average 0.28 mol/kg) can both be explained by the formation of modified seawater, while petrographic observations and pressure estimations (30‑44 mpa) suggest that boiling phenomena did not occur. based on the fluid characteristics, the formation of the described vein types (1, 2, and 3) belongs to the same hydrothermal process. modelling the temporal and spatial evolution of the system contributes significantly to our knowledge about the hydrothermal processes of the vms systems of the n-apennines, however, the results also illustrate the research efficiency and validity of the combination of fluid inclusion study, raman spectroscopy and chlorite thermometry. kiss: fluid inclusion study of the boccassuolo vms-related stockwork deposit (northern apennine ophiolites, italy) geologia croatica 301 acknowledgement giorgio garuti and federica zaccarini are thanked for providing the studied samples, for the information about the geological background, for the fruitful discussions and for the additional analysis of chlorite. the research instrument core facility (eötvös loránd university) and the eugen f. stumpfl electron microprobe laboratory (university of leoben) are thanked for the access to the raman and epma laboratories, respectively. the research of g. b. kiss was supported by the european union and the state of hungary, co‑financed by the european social fund in the framework of támop 4.2.4. a/1‑11‑1‑2012‑0001 ‘national excellence program’. constructive comments of three reviewers were invaluable in helping to improve the original manuscript. references abbate, e., brotolotti, v., principi, g. (1980): apennine ophiolites: a peculiar oceanic crust.– in: rocci, g. (ed.): tethyan ophiolites. ofioliti spec. issue, 1, 59–96. barrett, t.j. (1982): review of stratigraphic aspects of the ophiolite rocks and pelagic sediments of the vara complex, north apennines, italy.– ofioliti, 7/1, 3–46. barrett, j.j. & friedrichsen, h. (1989): stable isotopic composition of atypical ophiolitic rocks from east ligura, italy.– chem. geol., 80, 71–84. barrett, j.j. & spooner, e.f.c. (1977): ophiolitic breccias associated with allochtonous oceanic crustal rocks in the eastern ligurian apennines, italy – a comparison with observations from rifted oceanic ridges.– earth planet. sci. letters, 35, 79–91. barrie, c.t. & hannington, m.d. (1999): introduction: classification of vms deposits based on host rock composition.– in: barrie, c.t. & hannington, m.d. (eds.): volcanic‑associated massive sulfide deposits: processes and examples in modern and ancient settings. rev. econ. geol., 8, 2–10. barton, p.b. & bethke, p.m. (1987): chalcopyrite disease in spha lerite: pathology and epidemiology. am. mineral., 72, 451–467. baumgartner, m. & bakker, r.j. (2009): raman spectroscopy of pure h2o and nacl-h2o containing synthetic fluid inclusions in quartz – a study of polarization effects. miner. petrol., 95, 1–15. bertolani, m. (1953): i giacimenti cupriferi dell’appennino modenese. ricerche microscopiche a luce riflessa.– atti soc. nat. mat. modena, 82, 3–10. bodnar, r.j. (2003): reequilibration of fluid inclusions.– in: samson, i., anderson, a. & marshall, d. (eds.): fluid inclusions: analysis and interpretation. mineral. assoc. canada, short course, 32, 213– 230. bodnar, r.j., lecumberri-sanchez, p., moncada, d. & steele-macinnis, m. (2014): fluid inclusions in hydrothermal ore deposits.– in: holland, h.d. & turekian, k.k. (eds.): treatise on geochemistry, second edition, 13, 119–142. oxford: elsevier. bonatti, e., zerbi, m., kay, r. & rydell, h. (1976): metalliferous deposits from the apennine ophiolites: mesozoic equivalents of modern deposits from oceanic spreading centres.– bull. geol. soc. am., 87, 83–94. cabella, r., lucchetti, g. & marescotti, p. (1998): mn‑ores from eastern ligurian ophiolitic sequences (»diaspri di monte alpe »formation, northern apennines, italy).– trends mineral., 2, 1–49. cathelineau, m. & izquierdo, g. (1988): temperature – composition relationships of authigenic micaceous minerals in the los azufres geothermal system.– contrib. mineral. petrol., 100/4, 418–428. cortesogno, l., giannelli, g. & piccardo, g.b. (1975): petrogenesis and metamorphic evolution of the ophiolitic mafic rocks (northern apennine and tuscany).– boll. soc. geol. ital., 94, 291–327. cortesogno, l., galibati, b., principi, g. & venturelli, g. (1978): le brecce ofiolitiche della liguria orientale: nuovi dati e discussion sui modelli paleogeografici.– ofioliti, 3, 99–160. cortesogno, l., galbiati, b. & principi, g. (1987): note alla „carta geologica delle ofioliti del bracco” e riconstruzione della paleogeografia giurassico, cretacica.– ofioliti, 12, 261–342. dal piaz, g.v. (1974a): le métamorphisme alpin de haute pression et basse temperature dans l’évolution structurale de bassin ophiolitique alpino‑ apeninique, 1e partie.– boll. soc. geol. ital., 93, 437–468. dal piaz, g.v. (1974b): le métamorphisme alpin de haute pression et basse temperature dans l’évolution structurale de bassin ophiolitique alpino‑ apeninique, 2e partie.– schweitzer mineral. petrol. mitt., 57, 59–88. daoudi, l. & pot de vin, j.-l. (2002): thermal and hydrothermal effects of triassic–liassic basalt flow deposition on clays (agana basin, morocco).– c.r. geosci., 334/7, 463–468. de caritat, p., hutcheon, i. & walshe, j.l. (1993): chlorite geothermometry: a review.– clays clay miner., 41, 219–239. diamond, l.w. (2003): systematics of h2o inclusions.– in: samson, i., anderson, a. & marshall, d. (eds.): fluid inclusions: analysis and interpretation. mineral. assoc. can., short course ser., 32, 55–79. dilek, y. & furnes, h. (2011): ophiolite genesis and global tectonics: geochemical and tectonic fingerprinting of ancient oceanic lithosphere.– bull. geol. soc. am., 123, 387–411. dilek, y. & furnes, h. (2014): ophiolites and their origins.– elements, 10/2, 93–100. downs, r.t. (2006): the rruff project: an integrated study of the chemistry, crystallography, raman and infrared spectroscopy of minerals.– program and abstracts of the 19th general meeting of the international mineralogical association in kobe, japan, o03‑13. duan, z. & mao, s. (2006): a thermodynamic model for calculating methane solubility, density and gas phase composition of methane-bearing aqueous fluids from 273 to 523 k and from 1 to 2000 bar.– geochim. cosmochim. acta, 70, 3369–3386. elter, p. (1975): l’ensemble ligure.– bull. soc. geol. france, 17, 984–997. essene, e.j. & peacor, d.r. (1995): clay mineral thermometry – a critical perspective.– clays clay miner., 43, 540–553. etiope, g. & schoel, m. (2014): abiotic gas: atypical, but not rare.– elements, 10/4, 291–296. ferrario, a. & garuti, g. (1980): copper deposits in the basal breccias and volcanosedimentary sequences of the eastern ligurian ophiolites (italy). mineral. dep., 15, 291–303. foustoukos, d.i. & seyfried, w.e. (2007): fluid phase separation processes in submarine hydrothermal systems. rev. mineral. geochem., 65, 213–239. franklin, j. m., sangster, d.,m. & lydon, j.,w. (1981): volcanic associated massive sulphide deposits. econ. geol. 75th anniversary vol., 485–627. garuti, g. & zaccarini, f. (2005): minerals of au, ag and u in volcanic-rock-associated massive sulphide deposits of the northern apennine ophiolite, italy.– can. mineral., 43, 935–950. garuti, g., bartoli, o., scacchetti, m. & zaccarini, f. (2008): geological setting and structural styles of volcanic massive sulphide deposits in the northern apennines (italy): evidence for seafloor and sub‑seafloor hydrothermal activity in unconventional ophiolites of the mesozoic tethys. bol. soc. geol. mex., 60/1, 121–145. garuti, g. alfonso, p., zaccarini, f. & proenza, j.a. (2009): sulfur-isotope variations in sulphide minerals from massive sulphide deposits of the northern apennine ophiolites: inorganic and biogenic constraints. ofioliti, 34, 43–62. garuti, g., zaccarini, f., scacchetti, m. & bartoli, o. (2011): the pb-rich sulphide veins in the boccassuolo ophiolite: implications for the evolution of hydrothermal activity accross the ocean-continent transition in the ligurian tethys (northern-apennine, italy). lithos, 124, 243–254. goldstein, r. h. & reynolds, t. j. (1994): systematics of fluid inclusions in diagenetic minerals. soc. sedim. geol. short course, 31, 199 p. guillaume, d., teinturier, s., dubessy, j. & pironon j. (2003): calibration of methane analysis by raman spectroscopy in h2o–nacl– ch4 fluid inclusions. chem. geol., 194, 41–49. geologia croatica 68/3geologia croatica 302 herzig, p.m. & hannington, m.d. (1995): polymetallic massive sulphides at the modern seafloor: a review.– ore geol. rev., 10, 95–115. inverno, c.m.c., solomon, m., barton, m.d. & foden, j. (2008): the cu stockwork and massive sulfide ore of the feiteis volcanic‑hosted massive sulfide deposit, aljustrel, iberian pyrite belt, portugal: a mineralogical, fluid inclusion, and isotopic investigation.– econ. geol., 103, 241–267. ioannou, s.e., spooner, e.t.c. & barrie, c.t. (2007): fluid temperature and salinity characteristics of the matagami volcanogenic massive sulphide district, quebec. econ. geol., 102, 691–715. jiang, w.t., peacor, d.r. & buseck, p.r. (1994): chlorite geothermometry? – contamination and apparent octahedral vacancies.– clays clay miner., 42, 593–605. juteau, t., manac’h, g., moreau, o., lécuyer, c. & ramboz, c. (2000): the high temperature reaction zone of the oman ophiolite: new field data, microthermometry of fluid inclusions, pixe analyses and oxygen isotopic ratios.– mar. geophys. res., 21/3, 351–385. kiss, g., molnár, f. & zaccarini, f. (2012): fluid inclusion studies in datolite of low grade metamorphic origin from a jurassic pillow basalt series in northeastern hungary.– central eur. j. geosci., 4/2, 261– 274. kranidiotis, p. & maclean, w.h. (1987), systematics of chlorite alteration at the phelps dodge massive sulphide deposit, matagami, quebec.– econ. geol., 82., 1898–1911. lagabrielle, y. & lemoine, m. (1997): alpine, corsican and apennine ophiolites: the slow-spreading ridge model.– c. r. acad. sci. paris, 325, 909–920. lemoine, m., tricart, p. & boillot, g. (1987): ultramafic and gabbroic ocean floor of the ligurian tethys (alps, corsica, apennines): in search of a genetic model. geology, 15, 622–625. leoni, l., sartori, f. & tamponi, m. (1998), compositional variation in k‑micas and chlorites coexistiong in al‑saturated metapelites under late-diagenetic to low-grade metamorphic conditions (internal liguride units, northern‑apennines, italy).– eur. j. mineral., 10, 1321–1339. lombardo, b., rubatto, d. & castelli, d. (2002): ion microprobe u-pb dating of zircon from a monviso metaplagiogranite: implication for the evolution of the piedmont‑liguria tethys in the western alps.– ofioliti, 27/2, 119–131. lydon, j. w. (1984): some observations on the morphology and ore textures of volcanogenic sulfide deposits of cyprus. geol. surv. canada, curr. res., paper 84‑01a, 601–610. mernagh, t.p. & wilde, a.r. (1989): the use of the laser raman microprobe for the determination of salinity in fluid inclusions. geochim. cosmochim. acta, 53/4, 765–771. nehlig, p. (1991): salinity of oceanic hydrothermal fluids: a fluid inclusion study. earth planet. sci. letters, 102, 310–325. ohmoto, h. (1996): formation of volcanogenic massive sulphide deposits: the kuroko perspective. ore geol. rev., 10, 135–177. piccardo, g.b., rampone, e. & romairone, a. (2002): formation and composition of the oceanic lithosphere of the ligurian tethys: inferences from the ligurian ophiolites. ofioliti, 27/2, 145–161. pini, g.a. (1999): tectonosomes and olistostromes in the argille scagliose of the northern apennines, italy. geol. soc. am. spec. pap., 335, 1–70. pirajno, f. (2009): hydrothermal processes and mineral systems: springer, geological survey of western australia, 1250 p. plesi, g., daniele, g., chicci, s., bettelli, g., catanzariti, r., feroni, c., de nardo, m.t., martinelli, p., ottria, g. & panini, f. (2002): note illustrative della carta geologica d’italia alla scala 1:50.000, foglio 235 pievepelago : presidenza del consiglio dei ministri, servizio geologico d’italia, regione emilia romagna, 1–138. pognante, u. & piccardo, g.b., (1984): petrogenesi delle ofioliti delle alpi occidentali.– mem. soc. geol. ital., 29, 79–92. principi, g., cortesogno, l., cellai, d., gaggero, l., garuti, g., gazzotti, m., passerini, p. & treves, b. (1992): le ofioliti dell’apennino settentrionale : societá geologica italiana, 76a riunione estiva, firenze 24‑25‑26 settembre 1992, guide alle escursioni post‑ congresso, 1–76. rona, p.a. (1984): hydrothermal mineralization at seafloor spreading centres.– earth sci. rev., 20, 1–104. scott, s.d. (1997): submarine hydrothermal systems and deposits: in barnes, h.l. (ed.): geochemistry of hydrothermal ore deposits, 3rd ed.: new york, john wiley and sons, 797–875. sherlock, r.l., roth, t., spooner, e.t.c. & bray, c.j. (1999): origin of the eskay creek precious metal-rich volcanogenie massive sulphide deposit: fluid inclusion and stable isotope evidence.– econ. geol., 94, 803‑824. steele‑macinnis, m., han, l., lowell, r.p., rimstidt, j.d. & bodnar r.j. (2012): quartz precipitation and fluid inclusion characteristics in sub‑seafloor hydrothermal systems associated with volcanogenic massive sulphide deposits.– centr. eur. j. geosci., 4/2, 275–286. sun, q., zhao, l., li, n. & liu, j. (2010): raman spectroscopic study for the determination of cl− concentration (molarity scale) in aqueous solutions: application to fluid inclusions.– chem. geol., 272, 55–61. tornos, f. (2006): environment of formation and styles of volcanoge‑ nic massive sulphides: the iberian pyrite belt.– ore geol. rev., 28, 259–307. urabe, t., scott, s.d. & hattori, k. (1983): a comparison of footwall‑ rock interactions and geothermal systems beneath some japanese and canadian volcanogenic massive sulphide deposits.– econ. geol. monograph, 5, 345–364. wilkinson, j.j. (2001): fluid inclusions in hydrothermal ore deposits.– lithos, 55, 229–272. zaccarini, f. & garuti, g. (2008): mineralogy and chemical composition of vms deposits of northern apennine ophiolites, italy: evidence for the influence of country rock type on ore composition.– mineral. petrol., 94, 61–83. zaccarini, f., morales-ruano, s., scacchetti, m. & garuti, g. (2008): investigation of datolite (cabsio4oh) from basalts in the northern apennines ophiolites (italy): genetic implications. chemie erde – geochem., 86, 265–277. zengqian, h., zaw, k., rona, p., linquing, l., xiaoming, q., shuhe, s., ligui, p. & jianjun, h. (2008): geology, fluid inclusions, and oxygen isotope geochemistry of the baiyinchang pipe‑style volcanic-hosted massive sulphide cu deposit in gansu province, northwestern china.– econ. geol., 103, 269–292. manuscript received january 26, 2015 revised manuscript accepted september 05, 2015 available online october 31, 2015 www.geologia-croatica.hr abstract this study reports and discusses new radiometric ages, petrographic and volcanological observations and whole rock geochemical data of the rocks of the rudnik mts. volcanointrusive complex. the complex belongs to the serbo-macedonian metallogenic belt and hosts a pb-zn-ag deposit. two distinct igneous events are distinguished. the first occurred, >30 ma and was mainly characterized by extrusive and shallow intrusive dacites and andesi tes and was unrelated to mineralization. the second igneous event occurred <23 ma and was highly heterogeneous in terms of its volcanic products and petrographic varieties, but with a strong predominance of quartzlatites. the dacite-andesites (first event) and the quartzlatites (second event) are geochemically similar and both display a calc-alkaline affinity and highly incompatible element enriched patterns on spider diagrams. however, the younger quartzlatites are richer in k2o, rb and ba and poorer in sr. along with other petrochemical characteristics; this is taken as evidence that mixing between ultrapotassic lamprophyre/lamproite magma and an acid calc-alkaline (dacite-like) magma were essential petrogenetic processes of the second event. the proposed simplified volcanological model suggests that mixing was responsible for triggering strongly explosive volcanic activity and for providing the conditions for active hydrothermal and mineralization processes. the observed link between a specific magmatic phase and ore deposit formation can be a general phenomenon in the balkans, and must be addressed by further and more advanced studies. keywords: quartzlatite, dacite, magma mixing, serbo-macedonian metallogenic province article history: received october 02, 2015 revised and accepted january 09, 2016 avaliable online february 29, 2016 1. introduction the balkan sector of the alpine-himalayan orogenic belt is probably one of the best regions to study the relationship between magmatism and the formation of ore deposits. two roughly subparallel magmatic and metallogenic belts stretch through this region. the eastern one is referred to as the banatitetimok-srednjegorje magmatic and metallogenic belt; it is late cretaceous in age, and is associated with andesite to basaltic andesite, presumably subduction-related volcanic rocks, and is characterized by the cu-au±pb-zn metallogeny of huge porphyry systems and high sulphidation epithermal gold deposits (janković, 1997; von quadt et al., 2001, 2005; ciobanu et al., 2002, etc). the western belt stretches along the main axis of the balkan peninsula and is named the serbo-macedonian metallogenic (and magmatic) province (janković, 1966/67, 1984). it is cenozoic in age and is associated with predominantly pb-zn-ag±sb±w metallogeny. the cenozoic serbo-macedonian magmatic and metallogenic province is spatially and temporarily associated with magmatic rocks that have a wide compositional spectrum, from basalts to rhyolites and from tholeiitic to alkaline series (e.g. cvetković et al., 2004; prelević et al., 2005; mladenović et al., 2015). this compositional heterogeneity was the reason why at many places in this province, the interplay between magmatic and mineralization processes has only been vaguely established. a plethora of petrographic types and highly variable volcanogenic facies have prevented the researchers from reconstructing the rock petrogenesis in sufficient detail, which was the main prerequisite for better understanding of the link between magmatism and mineralization. over several decades recently, knowledge about the age, origin and evolution of cenozoic magmatism in the central balkans has seriously improved (cvetković et al., 2000a, b, 2001, 2004, 2007, 2013; jovanović et al., 2001; prelević et al., 2000, 2001a, b, 2004, 2005, 2007; koroneos et al., 2011; schefer et al., 2011; borojević šoštarić et al., 2012; mladenović et al., 2015, among others). these studies provided a solid basis for refining the existing tectonomagmatic models and for making important steps forward in recognizing those magmatic processes that were essential for the formation of ore deposits. although this information has already provoked new studies which suggest that some events of cenozoic magmatism were more important for mineralization than others (e.g. borojević šoštarić et al., 2012, 2013; cvetković et al., 2014; mladenović et al., 2015), there are still many places where the true links between igneous pro89-99 8 figs. doi: 10.4154/gc.2016.08 the rudnik mts. volcano-intrusive complex (central serbia): an example of how magmatism controls metallogeny vladica cvetković1, kristina šarić1, zoltán pécskay2 and axel gerdes3 1university of belgrade faculty of mining and geology, ðušina 7, 11000 belgrade, serbia (vladica.cvetkovic@rgf.bg.ac.rs; kristina.saric@rgf.bg.ac.rs) 2institute of nuclear research of the hungarian academy of sciences, bem ter 18/c, 41001 debrecen, hungary (zoltan.pecskay@gmail.com) 3johann wolfgang goethe-universität, institut für mineralogie, seckenberganlage 28, 60054 frankfurt am main, germany (gerdes@em.uni-frankfurt.de) vol. 69/1 90 cesses and the formation of ore deposits remain poorly constrained. in this paper we focus on the rudnik mts. volcano-intrusive complex that is situated in the very central part of the serbomacedonian metallogenic province. it is our opinion, that this area is where the relationship between the magmatic evolution and mineralization is very clear, albeit still insufficiently known. so far, there is only a simplistic view about the general contemporaneity of the cenozoic volcanism and mineralization (e.g. tošović, 1997, 2000; popović & umeljić, 2015). by reporting and discussing new radiometric age data, petrographic and volcanological observations and data on major and trace element whole rock concentrations, we try to reconstruct the magmatic evolution of the complex in unprecedented detail. we offer a volcanological model according to which the mineralization processes were genetically related to a younger igneous event that itself was controlled by magma mixing processes. 2. regional geology and geotectonic setting it is widely accepted that the general geotectonic setting of the central balkans was principally related to the formation, evolution and closure of the mesozoic (neo-)tethys (see schmid et al., 2008; robertson et al., 2009; cvetković et al., 2016). cenozoic geodynamics of this area evolved after the final consumption of tethyan relicts, and this geodynamic regime is still active today. the final tethyan closure gave rise to the consolidation of the complex dinaride – albanide – hellenide – carpathian – balkan section of the larger alpine–himalayan orogenic belt. the orogenic processes were controlled by continuous nto nw-directed movements of the adria plate that acted as an african promontory. albeit generally compressive, this geodynamics involved regional-scale plate reorganizations, and this made it possible for certain regions to evolve into strikeslip or even purely extensional tectonic styles. these geotectonic regimes, which were highly variable on the regional to local scale, were responsible for the formation of cenozoic magmatism and the accompanying continental depositional systems along this orogen. the cenozoic magmatism of the central balkan peninsula developed over a basement mostly composed of remnants of the tethyan lithosphere and crust. these remnants occur along a mega-suture composed of dismembered ophiolite thrust sheets, fragments of the underlying metamorphic basement of distal african plate, lithologically strongly heterogenous accretionary prism assemblages and various overlying overstep sequences, mainly flysches. the rudnik mts. volcano-intrusive complex is located in central serbia, around 80 km south of belgrade (see inset in figure 1). it is a nnw-sse elongated area that predominantly consists of two large masses of volcanic and shallow intrusive facies and an orefield located in-between (figures 1 and 2). the immediate basement of the complex is comfigure 1. a geological-volcanological map of the rudnik mts. volcano-intrusive complex; the map is produced according to the basic geological map 1:100.000, sheets gornji milanovac (filipović et al., 1978) and kragujevac (brković et al., 1980). cvetković et al.: the rudnik mts. volcano-intrusive complex (central serbia): an example of how magmatism controls metallogeny 91 posed of various cretaceous flysch sediments that range in age from the barremian-aptian to the turonian-senonian. below these sediments the basement is represented by jurassic peridotites and serpentinites. the flysch deposits are products of various turbiditic sequences represented by alternating greywacke, siltstones and shales. the terrigenous series contains numerous limestone olistoliths (filipović et al., 1978; brković et al., 1980). the volcanic rocks are temporarily associated with oligo-miocene sediments of the gornji milanovac lacustrine basin. the basin belongs to the dinaride lake system that represents a line of nnw-sse elongated intramontane basins. the basins are associated with either steeply dipping normal faults (marović et al., 1999) or the formation of metamorphic core complexes along low-angle normal faults (matenco & radivojević, 2012). the sediments of the gornji milanovac basin are represented by fresh water middle miocene marginal facies conglomerates that grade into dark-reddish sandstones (filipović et al., 1978). the terrigenous material contains abundant volcanic detritus that most likely originated by reworking of the rocks of the adjacent rudnik mts. volcano-intrusive complex. 3. sampling and analytical techniques 3.1. k-ar ages four k-ar analyses of biotite and two of k-feldspar mine ral separates, as well as one k-ar analysis of an unspecified mixture of mafic minerals were undertaken in the laboratory for k-ar age dating of the institute for nuclear research of the hungarian academy of sciences in debrecen (hungary). mineral separation involved crushing of whole rock samples and sieving to obtain the appropriate fraction. the separation was performed using a franz magnetic separator and heavy liquid separation. potassium concentrations were determined using flame photometry while applying an na buffer and li internal standard as well as asia 1/65, lp6, hd-b1, gl-o inter-laboratory standards. the samples were treated in an argon extraction line using rf fusion in molybdenum crucibles. a 38ar spike was added using a gas pipette system and the gas cleaning was done using ti and saes getters and liquid nitrogen traps. ar isotope ratios were measured in the static mode, using a 15 cm radius magnetic sector mass spectrometer. details about the instruments and methods can be found in balogh (1985). the radiometric ages were calculated according to the atomic constants of steiger & jaeger (1977). analytical errors represent one standard deviation, i.e. 68% analytical confidence level. 3.2. u-pb zircon dating uranium, thorium and lead isotopes were analysed using a thermoscientific element 2 sector field (sf)-icp-ms system coupled to a resolution m-50 (resonetics) 193 nm arf excimer laser (compexpro 102f, coherent) system at goethe-university frankfurt. data were acquired in timeresolved peak-jumping pulse-counting/analogue mode over 356 mass scans, with a 20 s background measurement followed by 21 s sample ablation. details about measurement conditions can be found in gerdes & zeh (2009). 3.3. major and trace element analyses major oxides and trace element analyses were carried out in the acme laboratories ltd. vancouver, canada. concentrations of major element oxides were determined by icp atomic emission spectrometry, with detection limits of approximately 0.001–0.04% (accuracy 2–5%), whereas trace element and rare earth elements (ree) concentrations were measured using icp-mass spectrometry (detection limits 0.01–0.5 ppm, accuracy 10–15% or better for trace elements and 1–5% for ree). std so-17 was certified inhouse against 38 certified reference materials including canmet sy-4 and usgs agv-1, g-2, gsp-2 and w-2 (karsli et al., 2007). the analyses are considered accurate within the limits for major elements. figure 2. petrography of various igneous rocks of the rudnik mts. volcano-intrusive complex. a) photomicrograph of holoto hypocrystalline porphyritic dacite (vidačevica quarry); the inset showing a partially digested upper-crustal xenolith from the same dacite; b) photomicrograph of coarsely porphyritic quartzlatite of extrusive facies (ćeramide quarry); note the presence of a partially exposed large sanidine phenocryst (lower left) and an embayed quartz phenocryst (lower right); the groundmass is micropoikilitic and can be misinterpreted for holocrystalline (see text for further explanations); the inset shows a euhedral and sieved plagioclase phenocryst from the same rock; c) partially resorbed biotite with sagenite inclusions (shallow intrusive quartzlatite); d) mostly monomict hydraulic-hydrothermal breccias spatially associated with mineralization (underground mine); note that quartzlatite fragments are distinctively angular and mineralized along their margins, e) photomicrograph of a polymict hydraulic-hydrothermal breccia (underground mine); f) photomicrograph of monzogranite taken from a borehole that cut strongly polymict hydraulic-hydrothermal breccia. vol. 69/1 92 4. results 4.1. field observations and rock petrography the following volcanic facies comprise the wider area of the rudnik mts. volcano-intrusive complex: 1) extrusive and shallow intrusive dacite and andesite, 2) extrusive and shallow intrusive quartzlatite, 3) monzogranite, 4) quartzlatiterhyodacite pyroclastic rocks, and 5) basaltoid rocks. the spatial distribution of the most abundant volcanic facies is given in the simplified geological-volcanological map (figure 1). in the following text we present the major petrographic and volcanological characteristics of the above listed rock facies that are grouped according to their radiometric age and geochemistry (see below). in addition, the spatial distribution of ore bodies within the rudnik mts. orefield is illustrated in figure 3 and a short description of mineralization types is given in subsection 4.1.6. 4.1.1 extrusive and shallow intrusive dacite and andesite dacite and andesite rocks occur as shallow intrusive facies in the north-westernmost part of the complex, and are best exposed in the vidačevica quarry (see figure 1). petrographically very similar dacite-andesite rocks are also found in boreholes near stragari, outside of the complex, around 10 km east of the rudnik mts. orefield. the rock mass in the vidačevica quarry is generally polygonally jointed but along its periphery the rocks are platy jointed and display a pronounced fluidal fabric. the dacite is hollocrystalline porphyrytic and polyphyric (>50 vol. % of phenocrysts) with seriate textures and consists of phenocrysts of plagioclase, quartz, biotite and amphibole, and microphenocrysts of the same minerals (figure 2a). quartz is relatively rare, subhedral and often shows embayments as effects of resorption. biotite is slightly more abundant than amphibole. they are very fresh and show typical pleochroism, whereas opacitization is only weakly developed. these volcanic rocks contain abundant crustal xenoliths (figure 2a, inset). the xenoliths range from a few cm to a few dm in length and represent fragments of various schists, gneiss and amphibolites. some xenoliths show the effects of contact-metamorphism along their margins. 4.1.2. extrusive and shallow intrusive quartzlatite extrusive volcanic facies of quartzlatitic composition are predominant in the rudnik mts. volcano-intrusive complex. there are two large quartzlatitic masses that extend in a nnw-sse direction and are separated by the rudnik mts. orefield (figure 1). in addition, there is a relatively large volcanic mass situated several kilometres east of the rudnik mts. orefield. the extrusive quartzlatites are exposed in many places and in particular in the ćeramide active quarry. they are platy to polygonally jointed and often show evidence of planparallel and fluidal fabric. the roof parts of these extrusions are represented by highly porous rocks and have a tuff-like appearance. this was the reason that these rocks were erroneously interpreted as pyroclastic deposits (filipović et al., 1978). the quartzlatite is porphyritic with variable phenocryst contents, but rarely above 30 vol.%. the phenocrysts are represented by quartz, plagioclase, sanidine, biotite and amphibole with apatite, zircon and opaques as accessories. the matrix is hypocrystalline and in some places the volcanic glass is replaced by micropoikilitic fine-grained textures (lofgren, 1971), which can easily be misinterpreted as holocrystalline (figure 2b). quartz is subhedral and often shows well developed embayments. plagioclase is euhedral and tabular in shape and it very often exhibits so-called ’sieved’ textures defined by the presence of tiny drop-like inclusions of glass (figure 2b, inset). such textures are commonly explained by partial resorption of plagioclase crystals, which implies nonequilibrium conditions during crystallization (nelson & montana, 1992). sanidine is ubiquitously present, but it can be as 10 cm crystals and, therefore, rarely present in thinsections (figure 2b). it is pale pinkish to white in colour and often shows typical carlsbad-type twinning. biotite occurs in the form of prismatic flakes, usually elongated in one direction, sometimes showing evidence of plastic deformation. it shows pleochroism in dark-red-brown colours. in some samples biotite contains needle-like sagenite inclusions and those biotite flakes usually show the effects of resorption (figure 2c). amphibole appears in prismatic and euhedral to subhedral phenocrysts. in some samples it is more abundant than biotite, in others it is almost totally lacking. one of the most important petrographic features of these quartzlatites is the presence of rounded to subrounded mafic microgranular enfigure 3. a geological sketch (radulović & erić, 1997) showing the spatial distribution of rock facies and orebodies within the rudnik mts. orefield. cvetković et al.: the rudnik mts. volcano-intrusive complex (central serbia): an example of how magmatism controls metallogeny 93 claves. the enclaves are lamprophyric in character and are rich in dark mica, sometimes accompanied by amphibole. in the south-eastern part of the complex a composite dome-like body composed of dacite – quartzlatite – leucominette occurs. this rock association is described in detail by prelević et al. (2000, 2001a). shallow intrusive quartzlatite occurs as a few metres to a few tens of meters thick discordant dykes or concordant silllike bodies, which are mostly, emplaced within cretaceous flysch sediments (figures 1 and 3). the dykes often appear on the surface, but they are abundant in the rudnik mts. orefield, in particular in the underground mine. the cretaceous sediments show the effects of contact-metamorphism, but without regularities between the contact-metamorphic grade and the thickness and orientation of these quartzlatite shallow intrusions. the contact-metamorphic rocks range in composition from only slightly thermally metamorphosed sandstones up to garnetand axinite bearing skarns. shallow intrusive quartzlatites are petrographically almost indistinguishable from the extrusive quartzlatites described above. they are hypoto holocrystalline porphyritic in texture and show variable abundance of phenocrysts. some dykes show chilled margins and are devoid of large sanidine phenocrysts. hydrothermal quartzlatite breccia represents a subgroup of shallow intrusive facies. they are spatially restricted to the rudnik mts. orefield and are found both at the surface and in the underground mine, in the latter case in close contact with mineralization. they are clast-supported mostly monomict breccias with highly unsorted angular fragments that sometimes show jigsaw puzzle fit structures. the fragments are usually strongly altered and sometimes heavily mineralized, especially along the margins of the volcanic fragments (figure 2d). the most important alterations are propylitization and silicification, whereas potassic alteration is subordinate. the fragments are cemented by highly variable material, from silicates, dominated by quartz and clay minerals through primary hydrothermal sulphides to supergene limonite. some breccias are polymict in character and consist of volcanic fragments of different textures, mineral compositions and the extent of alteration and mineralization as well as of those of adjacent contact-metamorphosed flysch sediments (figure 2e). the polymict breccia sometimes contains remarkably fresh fragments of equigranular rocks similar to monzogranite that is a separate lithology described below. 4.1.3. monzogranite the presence of plutonic rocks of monzogranite composition was first reported by brković et al. (1980) who described weak outcrops within the rudnik mts. orefield. these outcrops most likely represent the internal portions of thicker shallow quartzlatite intrusions. during our field campaign these rocks are found exclusively as individual fragments in the polymict hydrothermal breccia described above. the plutonic rocks show uniform petrographic characteristics and mineral compositions by displaying mediumrarely fine-grained hypidiomorphic granular texture and massive and homogeneous fabric (figure 2f). the monzogranite is composed of plagioclase, quartz, potash feldspar, biotite and subordinate amphibole. plagioclase is subhedral and, along with biotite and amphibole, constitutes the main crystal network, whereas the interstitial spaces are filled by quartz and perthitic potash feldspar. sphene, apatite, opaques and zircon are the most important accessory minerals. rare fragments of these rocks exhibit inequigranular texture with larger potash feldspar oikocrysts, which makes these rocks petrographically similar to the shallow intrusive quartzlatite. 4.1.4. quartzlatite-rhyodacite pyroclastic rocks these rock facies occur only in the most northwestern part of the complex (figure 1). in the wider area, they appear as irregular patches of volcaniclastic rocks that usually overlie cretaceous flysch deposits and are transgressively covered by mio-pliocene lacustrine strata. they are not addressed in detail in this study, but according to our field observations in the most northwestern part of the complex as well as according to data from the basic geological map of the sfr of yugoslavia, sheets kragujevac and gornji milanovac (filipović et al., 1978; brković et al., 1980, respectively), these rocks correspond to rarely preserved unwelded to welded ignimbrites. more rarely, they represent various reworked and redeposited primary pyroclastic deposits (terzić & terzić, 1972). dense juvenile fragments of these pyroclastic rocks are porphyritic with glassy to hypocrystalline groundmass and are petrographically very similar to the extrusive quartzlatites described earlier. although the juvenille pyroclasts only rarely contain large sanidine phenocrysts, they are characterized by sieved plagioclase phenocrysts and often contain partially resorbed biotite and hornblende. 4.1.5. basaltoid rocks basaltoid rocks of the wider rudnik mts. complex are studied petrologically in detail by cvetković et al. (2004) and prelević et al. (2005). these rocks have negligible volumes in comparison to the acid to intermediate rocks described above, and mostly occur as several metre thick dykes and sills or lava plugs, rarely as lava flows. they range in composition from calc-alkaline, mediumand high-k calcalkaline basalts to those showing ultrapotassic affinity and displaying minette or lamproite petrographic characteristics. as previously mentioned above, prelević et al. (2000, 2001a) reported the presence of hybrid rocks in the southeastern part (beli kamen) of the complex and called them leucominette. 4.1.6. the rudnik mts. orefield presenting detailed characteristics of the rudnik mts. polymetallic deposit is beyond the scope of this study. therefore, in this subsection we only briefly summarize what is generally known about this complex deposit (milić, 1972; janković et al., 2003; tošović, 1997, 2000). as it is shown in figure 3, the rudnik mts. orefield is an elongated area composed of contact metamorphosed clastic and carbonate flysch sediments. the contact metamorphic zone hosts several elongated areas of hydrothermal breccia and numerous quartzlatite dyke-like shallow intrusive facies. these rock facies, which have already been described above, are closely spatially associated to numerous orebodies, which indicates that mineralization is most likely associated with the same structures that were used by the quartzlatite magma. vol. 69/1 94 the orebodies have variable morphology, most often, they are platy to veinand lens-like. the orebodies range in size from 10 m3 to 7x103 m3 or even up to 3x105 m3. they display two general modes of occurrence: 1) gently dipping, up to 2 m thick lenses that can be traced for 150-350 m; they are mainly spatially associated to contact-metamorphosed limestone blocks within the flysch sediments, and 2) predominantly high dipping platy bodies located within the subvolcanic quartzlatites (milić, 1972). tošović (1997) recognized roughly two major stages of mineralization processes in this area. the first that occurred was skarn mineralization associated in time with formation of the contact metamorphic rocks. this mineralization is only locally developed but in some places contains significant amounts of scheelite, magnetite and subordinate cassiterite (stojanović et al., 2006). the skarn mineralization is overprinted by the formation of hydrothermal replacements and structure-controlled veins and lenses. during this stage the most important orebodies originated. the mineralogy of these orebodies is dominated by pyrrhotite which often shows transitions to ni-bearing pyrrhotite, sphalerite, galenite, chalcopyrite and subordinate arsenopyrite. the pb-zn grade in these ore bodies is highly variable but mostly around 7-8 %. in addition, the ore contains up to 0.5 %, 150 ppm and 450 ppm of cu, ag and bi, respectively (janković et al., 2003). 4.2. k-ar and u-pb radiometric ages seven so far unpublished k-ar age determinations and 11 k-ar ages published earlier are reported together in table 1. a mixture of mafic minerals of the hydrothermally altered sample r-19 revealed the largest relative error of > 20 %. because this sample is also characterized by low potassium contents and a low concentration of radiogenic argon, the obtained age of 39±9.2 ma is discarded. however, given that this sample was very important with respect to defining the maximum age of the mineralization, zircons from the sample were analyzed by la-icp-ms on u-pb. the results shown in figure 4 gave a concordia u-pb age of 22.99 ±0.28 ma. all other biotite and k-feldspar separates gave k-ar ages with relatively small errors (< ±1.13 ma), consequently, their ages are reliable and considered to be close to the time of crystallization. there are two groups of ages. one is oligocene and was obtained on the extrusive dacite from the vidačevica quarry (35.30±1.09 ma) and on the shallow intrusive andesite in a borehole near stragari (35.69±1.13 ma). the other group is represented by the latest oligocene to early miocene ages (roughly 19-23 ma). they are obtained by various volcanic quartzlatitic facies that include massive (19.02±0.59 ma) to porouse (20.44±0.67 ma) extrusive quartzlatites, unaltered quartzlatite, breccia from the underground mine (22.97±0.72 ma), and monzogranite from a borehole in the rudnik mts. orefield (23.14±0.73 ma). such a bimodal distribution is observed in other available k-ar ages. these data also show two ranges, one between 29 figure 4. concordia u-pb diagram for zircons from a hydrothermally altered and mineralized sample r-19. figure 5. total alkali vs silica classification diagram (a le bas et al., 1986) and the sio2 vs k2o diagram (b peccerillo & taylor, 1976) for studied rocks of the rudnik mts. volcano-intrusive complex. cvetković et al.: the rudnik mts. volcano-intrusive complex (central serbia): an example of how magmatism controls metallogeny 95 ma and 32 ma and another that ranges from 26 ma to 19 ma. one k-ar age obtained on olivine trachyte from boljkovac (terzić & svešnjikova, 1991), is remarkably older than all the known ages of cenozoic igneous rocks of this area, and must be excluded. although it is not easy to exactly compare the lithologies that were investigated in this study and those for which the older k-ar age determinations exist, the following conclusions can be derived. firstly, dacite-andesite rocks are oligocene and are systematically older than all facies of quartzlatitic composition, which are early miocene in age. secondly, the monzogranite originated more or less contemporaneously with the quartzlatite. thirdly, mineralization most likely formed immediately after the shallow intrusive quartzlatite had crystallized. 4.3. whole rock geochemistry so far unpublished whole rock major and trace element concentrations, including rees, for the various rudnik mts. igneous rocks are reported in table 2. data mainly for basaltoid and leucominette rocks are taken from the literature (prelević et al., 2001a, 2005; cvetković et al., 2004) and are plotted in diagrams below. according to the total alkali vs silica classification diagram (le bas et al. 1986) and the sio2 vs k2o diagram (peccerillo & taylor, 1976) (figures 5a, b) it is evident that: 1) the rudnik mts. magmatic rocks predominantly correspond to acid to intermediate rocks with silica contents above 55 wt.%, with subordinate intermediate to basic rocks, 2) most rocks correspond to subalkaline and to highto medium-k calc-alkaline trend, with the exception of basaltoid rocks that are ultrapotassic to shoshonitic in character (foley et al., 1987), 3) the rocks petrographically classified as quartzlatites are mainly medium-k calc-alkaline and plot along the line between the dacite and rhyolite fields, with some samples stretching into the trachydacite field, 4) the samples petrographically determined as monzogranite plot very close to the quartzlatites, 5) four samples plot in the andesite and dacite field which is in accordance with their petrography, and 5) two samples of hydrothermally altered quartzlatite have very low silica and alkali contents and this most likely does not reflect their primary composition. in addition, the dacite and andesite samples show slightly higher al2o3 (mostly >15 wt.%) and cao (mostly 3-5 wt.%) contents in comparison to the quartzlatitic rocks (al2o3 mostly <15 wt.%, and cao mostly <3 wt.%). in figures 6a, b primitive mantle-normalized trace element and chondrite-normalized ree concentrations (mcdonough & sun, 1995) are plotted. the spider diagram patterns of all the studied rocks are fairly similar and are characterized by spiked large ion lithophile elements as well as light ree-enriched shapes. these are typical patterns of rocks crystallized from magmas in which petrogenesis continental crustal material has been largely involved. despite this generally similar geochemical signature, the studied samples show subtle, but observable differences. for instance, all rocks that belong to quartzlatite facies show identical geochemical patterns, and these are remarkably similar to the pattern shown by a monzogranite sample. on the other hand, dacite and andesite rocks exhibit mutually indistinguishable trace element and ree patterns that are slightly different from those shown by quartzlatites. namely, the pattern of dacite and andesite rocks shows a distinctive sr positive anomaly, but lacks negative anomalies for ba and eu and there is a relatively flat pattern of heavy rees. for instance, dy/lu is <11 and >13 in the dacite-andesite and in the quartzlatite, respectively. 5. discussion the field and petrographic observations presented above as well as new and previously published radiometric and geochemical data provide conditions for better understanding the origin and evolution of the rudnik mts. volcano-intrusive complex. previously, there was a strong mismatch between a highly variable rock petrography and volcanic facies, on one side, and fragmentary information about petrology and geochemistry and the radiometric age of the volcanic and intrusive rocks. in the following discussion we first establish the relationship between radiometric ages and the inferred rock compositions, then, we discuss the younger quartzlatite volcanic event as the most significant in terms of the volume of volcanic products and with respect to its significance for mineralization processes. finally, we propose a simplified volcanological model for the entire rudnik mts. volcano-intrusive complex. 5.1. the time-compositional framework of the rudnik mts. volcano-intrusive complex the available radiometric analyses indicate that there is a coupling between the age and the composition of the rudnik mts. igneous rocks. the extrusive to subvolcanic dacite and andesfigure 6. primitive mantle(a) and chondrite(b) normalized trace element and ree concentrations for the studied rocks of the rudnik mts. volcano-intrusive complex; coefficients for normalization after mcdonough & sun (1995). vol. 69/1 96 ite rocks, which are strongly subordinate in volume, show an oligocene age of around 35 ma. this age is similar to an unpublished k/ar age of around 32 ma (table 1) obtained on a petrographically very similar dacite from slavkovica, located around 15 km west of the rudnik mts. (terzić & vukov, 1984). alternatively, volcanic and shallow intrusive quartzlatite facies as well as monzogranite from a borehole are clearly younger and have radiometric ages ranging between 19 ma and 23 ma. the u-pb zircon age of 22.99 ±0.28 ma obtained from a strongly hydrothermally altered and mineralized hydrothermal quartzlatitic breccia delimits the maximum age of mineralization and suggests that formation of the ore deposit was temporarily and, most likely, also petrogenetically associated with the quartzlatites. the available ages of basaltoid rocks of the wide rudnik mts. area range between 24 ma and 32 ma (cvetković et al., 2004; prelević et al., 2005), which suggests that basaltoid magmatism was likely active during both the afore-mentioned events. although there are no radiometric ages of basaltoid rocks younger than 24 ma, there is solid evidence that mafic magma similar in composition to lamprophyre-lamproite co-existed with acid melts during the younger volcanic event when most of the quartzlatite originated. in particular, much textural evidence, such as the presence of mafic microgranular enclaves, sieved plagioclase phenocrysts, co-existing phlogopite (mg#[molmg/mg+fetot] up to 0.91) and biotite (mg# up to 0.61) (prelević et al., 2001a), partially resorbed mafic phenocrysts as well as the occurrence of large composite extrusions in the area of beli kamen (prelević et al., 2000, 2001a), imply that mixing between a lamprophyric to lamproitic magma and a dacitic melt has played a significant role in the quartzlatite petrogenesis. this can be taken as ample evidence that basaltoid magmatism was active up to the end of the complex formation. moreover, it can be postulated that geodynamic conditions during the oligocene favoured the emplacement of individual and distinct pulses of basaltoid magma, whereas those that were active at the beginning of the miocene enabled injection of similar basaltoid melts into already existing reservoirs of acid magma (see mladenović et al., 2015). 5.2. quartzlatite volcanism: the link between magmatism and mineralization the time and compositional constraints presented above demonstrate that the rudnik mts. volcano-intrusive complex is predominantly composed of various products of magma of quartzlatite composition, all of which formed roughly simultaneously <23 ma ago. furthermore, there are strong indications that these quartzlatite volcanic, subvolcanic and intrusive facies were emplaced via a continuous succession of volcanic events, which were ultimately followed by hydrothermal stages and precipitation of pbzn mineralization. it is also almost indisputable that magma mixing has played a crucial role in the volcanic events that produced the rudnik mts. quartzlatites. the petrographic evidence has already been listed above and here we discuss additional aspects that are closely related to rock geochemistry, volcanology and, supposedly, to mineralization processes. petrological and geochemical consequences of mixing between lamproiteand dacite-like magmas have already been recognized and explained in other cenozoic provinces of the balkan peninsula. the most comprehensive study was by prelević et al., (2004) on the hybrid rocks from the veliki majdan area in western serbia, suggesting that magma mixing may be a common process for lamprophyre formation. prelević et al. (2000, 2001a) described similar processes near beli kamen in the southeastern part of the rudnik mts. volcano-intrusive complex. they recognized petrographic and geochemical transitions between leucominette and the rhyodacite part of the extrusion and attributed this to hybridization. according to their model, hybridization occurred after a lamproite-like magma had invaded the base of an already stratified chamber with dacitic magma; this induced turbulent fountains and formation of more mafic leucominette facies. similar magma mixing processes were reported in the adjacent miocene borač complex (cvetković & pecskay, 1999; cvetković et al., 2001). furthermore, they considered that the injection of lamproite-lamprophyre melts has served as a trigger for plinian explosive activity. the data from this study are insufficient to refine the model of prelević et al. (2001a) to any significant extent. however, our data can be used to illustrate relatively simple geochemical variations that imply magma mixing processes. diagrams that show figure 7. plots of mgo (wt.%) vs zr (ppm) and mgo (wt.%) vs al2o3 (wt.%)/zr (ppm) for unaltered rocks of the rudnik mts. volcanointrusive complex. cvetković et al.: the rudnik mts. volcano-intrusive complex (central serbia): an example of how magmatism controls metallogeny 97 different variation paths for dacite-andesite and quartzlatite rocks of the rudnik mts complex are given in figures 7a, b. from the plots of mgo (wt.%) vs zr (ppm) and mgo (wt.%) vs al2o3 (wt.%)/zr (ppm) diagrams it is evident that: 1) dacite-andesite rocks plot close to upper crustal compositions reflected by the composition of cretaceous flysch deposits, 2) these rocks form trends of increasing zr contents and al2o3/zr ratios with decreasing mgo contents, which implies the effects of assimilation plus fractional crystallization processes (afc), 3) these trends are distinct with respect to the trends shown by quartzlatites, leucominette and basaltoid (lamprophyre-lamproite) rocks, and 3) the latter trends suggest compositional mixing between melts similar in composition to the most evolved dacite (the continuation of the dacite-andesite trend) and basaltoid (lamprophyre-lamproite) melts. this is exactly what is suggested by both field and petrographic evidence. these mixing processes had very important consequences with respect to volcanic activity and mineralization. first, as already mentioned, it most likely provided conditions for triggering large-scale explosive eruptions that produced widespread pyroclastic products. second, the injection of water-laden lamprophyric-lamproitic melts may have delivered additional water to the resulting hybridized magma, and this could have been crucial for enabling secondary boiling, even in a magma that previously degassed via strong explosive activity. it can therefore be postulated that without these injections of mafic melts, the magma chamber would probably be emptied by explosions, but it would have occurred later and have not led to subsequent hydrothermal and mineralization phases. finally, the mixing was responsible for the generation of a wide spectrum of volcanic facies and petrographic rock varieties. the volcanological and petrographic variability imposed great problems for earlier investigators, because their descriptions were overburdened by dozens of different rock varieties, such as: dacite, quartzlatite, rhyodacite, lamprophyre, lamproite, leucitite, leucite basanite, minette, kajanite, trachybasalt, trachyandesite, latite, trachyte, and so on and so forth. such a ‘flood’ of petrographic names prevented them from understanding the rock petrogenesis in sufficient detail and to produce valid tectonomagmatic interpretations. our volcanological observations indicate that the breccia occurring in the rudink mts. orefield most likely originated in response to hydraulic fragmentation events that are readily produced by subsurface decompression of fluids (e.g. cas & wright, 1987). phillips (1972) produced a model for these brecciation processes and for the formation of mostly subvertical, pipe-or dyke-like brecciated zones. given that these breccias appear at many places on the surface, it is likely that at least some of them represented diatremelike structures that originated via phreatic explosions. the hydrothermal fluids that generated brecciation were also responsible for precipitating mineralization, and that is evident from the fact that ore is often deposited in the matrix of these breccias, i.e. some fragments are cemented by ore minerals. the presence of strongly polymict breccia can indicate that some of these rocks may be polyphase in origin and can be associated with tectonic processes as well. these processes can be responsible for the presence of equigranular monzogranite fragments within the polymict breccias. the granular monzogranite facies probably represent parts of a presumably large unexposed magmatic body, whereas subvolcanic quartzlatitic bodies, which are found both in the underground mine and on the surface, can be apophyses of this intrusive. 5.3. a simplified volcanological model a schematic volcanological model for the rudnik mts. volcanointrusive complex is given in figure 8. the model summarizes in a most simplistic way all of the available information and proposes a possible succession of igneous processes from the early oligocene to the early miocene. the first igneous event occurred >30 ma. when the extrusive and shallow intrusive dacites and andesites originated (figure 8a). as evidence of explosive volcanic activity at this stage is lacking, the model assumes that the event was exclusively associated with extrusive to shallow intrusive activity. figure 8. a simplified volcanological model for the rudnik mts. volcano-intrusive complex (see text for explanation). vol. 69/1 98 volcanic processes recurred after a repose period of several million years, by the beginning of the miocene (~23 ma). it is very likely that during this time, formation of lacustrine depositional systems also occurred (figure 8b). this synthesis suggests that before the second magmatic event in the area of the present day rudnik mts. orefield a large and presumably stratified magma chamber existed (figure 8c). due to advanced magmatic differentiation, the roof parts of this magmatic chamber were extremely depleted in crystals and enriched in magmatic gases, whereas its internal parts were progressively less gasand more crystal-rich. the model involves a scenario according to which the chamber hanging wall did not collapse due to a simple overpressurisation of the underlying gas-rich magma, but in response to injections of water-saturated lamproite-like mafic melts from beneath (figure 8d). this triggered huge explosive volcanic activity that probably had plinian to sub-plinian characteristics and produced large eruption columns and various pyroclastic fall and pyroclastic flow deposits (figure 8e). this stage left behind numerous relicts of welded to non-welded ignimbrites and subordinate lapilli-fall deposits. after the gas-rich roof magma portions had emptied, crystal-rich and gas-poor melts reached eruption levels. this gave rise to formation of various coherent quartzlatite facies, from high-aspect ratio extrusions and lava domes to variously shaped subvolcanic intrusions (figure 8f). the presence of granular textured monzogranite as well as strong contact metamorphic effects indicate that large masses of quartzlatite did not reach the surface, but remained to crystallize at shallow crustal levels. on crystallization of these magmatic masses, the igneous processes in the rudnik mts. area terminated. the phase of formation of polymetallic mineralization followed the afore-mentioned magmatic events. the precipitation of mineralization was controlled by a large hydrothermal system that developed in the hanging wall of the solid but still hot magmatic intrusive body. as already argued above, this model proposes that incorporation of lamproite-like and water-rich mafic melts contributed greatly to the hydrothermal potential of the acid magma. decompression of these fluids induced subsurface and superficial brecciation and deposition of ore minerals (figure 8g). 6. conclusions this study demonstrates that there is still room for large improvements in our understanding of how igneous and metallogenic processes were linked during cenozoic magmatism of the balkan peninsula. the main conclusions are as follows: 1. the rudnik mts. volcano-intrusive complex formed in two magmatic events. 2. the first magmatic event was associated with the formation of extrusive to shallow intrusive dacites; this phase occurred before 30 ma. 3. the second event developed around 23 ma. it was much more heterogeneous in terms of volcanic activity and magmatic products; this magmatism produced various products of quartzlatitic magma depending on the crystallization conditions. 4. one of the most prominent petrogenetic processes of the second event was mixing between a lamproite-like magma and dacitic melts; this process most likely triggered large explosive plinian to sub-plinian events. 5. according to the simplified volcanological model, magma mixing was crucial for mineralization processes in the rudnik mts. volcano-intrusive complex; injected lamproite-like and water-saturated melt provided conditions for a strong hydrothermal phase, formation of hydraulic breccia and precipitation of ore minerals. acknowledgement the authors thank ‘rudnik and flotation rudnik’ for permitting publication of data which were part of a volcanological study done for the needs of the company. discussions with dejan prelević were extremely important in formulating some of the ideas in the manuscript. we thank marina lazarov for help with zircon separation and la-icp-ms analyses. the study was partly financed by the project oi176016 funded by the ministry of education, science and technological development of the republic of serbia and by serbian academy of sciences and arts. the editorial handling by v. bermanec and l. palinkaš as well as constructive reviews by s. borojević šoštarić and m. belak is appreciated. references balogh, k. (1985): k/ar dating of neogene volcanic activity in hungary: experimental technique, experiences and methods of chronologic studies.– ”atomki“, rep. d/1., 277–288. borojević šoštarić, s., cvetković, v., neubauer, f., palinkaš, l.a., bernroider, m. & genser, j. (2012): oligocene shoshonitic rocks of the rogozna mts. (central balkan peninsula): evidence of petrogenetic links to the formation of pb-zn-ag ore deposits.– lithos, 148, 176–195. borojević šoštarić, s., palinkaš, l.a., neubauer, f., hurai, v., cvetković, v., roller-lutz, z., mandić, m. & genser, j. (2013): silver-base metal epithermal vein and listwanite hosted deposit crnac, rogozna mts., kosovo, part ii: a link between magmatic rocks and epithermal mineralization.– ore geology reviews, 50, 98–117. brković, t., radovanović, z. & pavlović, z. (1980): osnovna geološka karta sfrj 1:100000. tumač za list kragujevac l34-138 [basic geological map of sfry 1:100000, geology of the kragujevac sheet – in serbian].– savezni geološki zavod, beograd, 60 p. cas, r.a.f. & wright, j.v. (1987): volcanic successions.– kluwer academic publishers, 544 p. ciobanu, c., cook, n. & stein, h. (2002): regional setting and geochronology of the late cretaceous banatitic magmatic and metallogenetic belt.– mineralium deposita 37, 541–567. doi: 10.1007/s00126-002-0272-9 cvetković, v., knežević, v. & pecskay, z. (2000a): tertiary igneous formations of the dinarides, vardar zone and adjacent regions: from recognition to petrogenetic implications.– in: karamata, s. & janković, s. (eds.): geology and metallogeny of the dinarides and the vardar zone. the academy of sciences and arts of the republic of srpska, collections and monographs 1, dpt. of natur., math. and techn. sci., 1, 245–253. cvetković, v., prelević, d. & pecskay, z. (2000b): lamprophyric rocks of the miocene borač eruptive complex (central serbia, yugoslavia).– acta geol. hung., 43/1, 25–41. cvetković, v. & pécskay, z. (1999): the early miocene eruptive complex of borač (central serbia): volcanic facies and evolution over time. extended abstract. carpathian geology 2000, october 11–14, 1999, smolenice.– geologica carpathica, 50, 91–93. cvetković, v., poli, g. & prelević, d. (2001): eruptive history and lowpressure evolution of the early miocene borač eruptive complex (central serbia). in: downes, h. & vaselli, o. (eds.): tertiary magmatism in the dinarides balkan peninsula.– acta volcanologica, 13/(1/2), 127–143. cvetković, v., poli, g., christofides, g., koroneos, a., pecskay, z., resimić-šarić, k. & erić, v. (2007): the miocene granitoid rocks of mt. bukulja (central serbia): evidence for pannonian extension-related granitoid magmatsim in the northern dinarides.– eur. j. mineral., 19/4, 513–532. doi: 10.1127/0935-1221/2007/0019-1736 cvetković, v., prelević, d., downes, h., jovanović, m., vaselli, o. & pecskay, z. (2004): origin and geodynamic significance of tertiary cvetković et al.: the rudnik mts. volcano-intrusive complex (central serbia): an example of how magmatism controls metallogeny 99 post-collisional basaltic magmatism in serbia (central balkan peninsula).– lithos, 73, 3–4, 161–186. doi: 10.1127/0935-1221/2007/0019-1736 cvetković, v., prelević, d. & schmid, s. (2016): geology of southeastern europe.– in: papić, p. (ed.): mineral and thermal waters of southeastern europe. springer, 1–30. doi: 10.1007/978-3-319-25379-4_1 cvetković, v., šarić, k., prelević, d., genser, j., neubauer, f., höck, v. & von quadt, a. (2013): an anorogenic pulse in a typical orogenic setting: the geochemical and geochronological record in the east serbian latest cretaceous to palaeocene alkaline rocks.– lithos, 180–181, 181–199. doi: 10.1016/j.lithos.2013.08.013 cvetković, v., šarić, k., pecskay, z. & gerdes, a. (2014): had late oligocene-early miocene magmatism in the dinarides different phases: the case study of the rudnik mts. volcanic complex. proceedings of xx cbga congress, tirana, albania, 24–26 september 2014. bul. shk. gjeol., 1/2014 – special issue 432 p. filipović, i., marković, b., pavlović, z., rodin, v. & marković, o. (1978): osnovna geološka karta sfrj 1:100000. tumač za list gornji milanovac l34-137 [basic geological map of sfry 1:100000, geology of the gornji milanovac sheet – in serbian].– savezni geološki zavod, beograd, 65 p. foley, s.f., venturelli, g., green, d.h. & toscani, l. (1987): the ultrapotassic rocks: characteristics, classification and constraints for petrogenetic models.– earth science reviews, 24, 81–134. doi: 10.1016/ 0012-8252(87)90001-8 gerdes, a. & zeh, a. (2009): zircon formation versus zircon alteration-new insights from combined u–pb and lu–hf in situ la-icp-ms analyses, and consequences for the interpretation of archean zircon from the central zone of the limpopo belt.– chemical geology, 261, 230–243. janković, s. (1997): the carpatho-balkanides and adjacent area: a sector of the tethyan eurasian metallogenic belt.– mineralium deposita, 32, 426–433. janković, s. (1966/67): metalogenetske provincije i epohe u jugoslaviji.– zbornik radova rudarsko-geološkog fakulteta, beograd, 9/10, 57–83. janković, s. (1984): major metallogenic units and ore deposits in yugoslavia.– exp. memoir of the metallogenic map of europe, 1:2500000, inesco, paris, 385–395. janković, s., jelenković, r. & vujić, s. (2003): mineral resources and potential prognosis of metallic and non-metallic mineral raw materials in serbia and montenegro at the end of the xx century. engineering academy of serbia and montenegro, section of mining and geology sciences, special issue 2, beograd, p. 876, isbn: 86-903409-3-x. jovanović, m., downes, h., vaselli, o., cvetković, v., prelević, d. & pecskay, z. (2001): paleogene mafic alkaline volcanic rocks of east serbia.– in: downes, h. & vaselli, o. (eds.): tertiary magmatism in the dinarides balkan peninsula.– acta volcanologica, 13, 1/2, 159–173. karsli, o., chen, b., aydin, f. & sen, c. (2007): geochemical and sr-nd-pb isotopic compositions of the eocene dolek and saricicek plutons, eastern turkey: implications for magma interaction in the genesis of high-k calc-alkaline granitoids in a post-collision extensional setting.– lithos, 98, 67–96. koroneos, a., poli, g., cvetković, v., christofides, g., krstić, d. & pecskay, z. (2011): petrogenesis and tectonic inferences from the study of the mt. cer pluton (west serbia).– geol. mag., 148, 1, 89–111. le bas, m.j., lemaitre, r.w., streckeisen, a. & zanettin, b. (1986): a chemical classification of volcanic rocks based on the total alkalisilica diagram.– journal of petrology, 27, 745–750. lofgren, g. (1971): experimentally produced devitrification textures in natural rhyolitic glass.– geological society of america bulletin, 82, 111–123. doi: 10.1130/0016-7606(1971)82%5b111:epdtin%5d2.0.co;2 matenco, l. & radivojević, d. (2012): on the formation and evolution of the pannonian basin: constraints derived from the structure of the junction area between the carpathians and dinarides.– tectonics, 31, 6, tc6007, doi: 10.1029/2012tc003206. marović, m., krstić, n., stanić, s., cvetković, v. & petrović, m. (1999): the evolution of neogene sedimentation provinces of central balkan peninsula.– bulletin of geinstitute, 36, 25–94. mcdonough, w.f. & sun, s.s. (1995): the composition of the earth.– chemical geology, 120/ (3–4), 223–253. doi: 10.1016/0009-2541(94)00140-4 milić, č.r. (1972): rudonosne strukture i faktori kontrole orudnjavanja prostora u polimetaličnom ležištu rundik.– zbornik radova vii kongresa geologa sfrj, zagreb, iii, 111–124. mladenović, a., trivić, b. & cvetković, v. (2015): how tectonics controlled post-collisional magmatism within the dinarides: inferences based on study of tectono-magmatic events in the kopaonik mts. (southern serbia).– tectonophysics, 646, 36–49, doi: 10.1016/j.tecto.2015.02.001 nelson, s.t. & montana, a. (1992): sieve-textured plagioclase in volcanic rocks produced by rapid decompression.– am. mineral., 77, 1242–1249. peccerillo, a. & taylor, s.r. (1976): geochemistry of eocene calcalkaline volcanic rocks from kastamonu area, northern turkey.– contributions to mineralogy and petrology, 58, 63–81. phillips, w.j. (1972): hydraulic fracturing and mineralisation.– journal of the geological society of london, 128, 337–359. popović, r. & umeljić, g. (2015): metalogenija planine rudnik (pozicija u vremenu i prostoru). povremena izdanja rudnik i flotacija ’rudnik’ doo rudnik, beograd, 224 p., isbn: 978-86-918511-0-1. prelević, d., cvetković, v. & foley, s.f. (2001a): composite igneous intrusions from serbia: two case studies of interaction between lamprophyric and granitoid magmas.– in: downes, h. & vaselli, o. (eds.): tertiary magmatism in the dinarides balkan peninsula.– acta vulcan., 13, 145–157. prelević, d., foley, s., cvetković, v., jovanović, m. & melzer, s. (2001b): tertiary ultrapotassic rocks from serbia, yugoslavia.– in: downes, h. & vaselli, o. (eds.): tertiary magmatism in the dinarides balkan peninsula.– acta vulcan., 13, 116–135. doi: 10.1130/2007.2418(06) prelević, d., cvetković, v. & jovanović, m. (2000): the composite dome of beli kamen (mt. rudnik, central serbia) – the example of a specific interaction of lamprophiric and granitoid magma.– in: karamata, s. & janković, s. (eds.): geology and metallogeny of the dinarides and the vardar zone. the academy of sciences and arts of the republic of srp ska, collections and monographs 1, dpt. of natur., math. and techn. sci. 1, 255–267. prelević, d., foley, s.f., cvetković, v. & romer, r.l. (2004): origin of minette by mixing of lamproite and dacite magmas in veliki majdan, serbia.– j. petrol., 45/4, 759–792. doi: 10.1093/petrology/egg109 prelević, d., foley, s.f., romer, r.l., cvetković, v. & downes, h. (2005): tertiary ultrapotassic volcanism in serbia: constraints on petrogenesis and mantle source characteristics.– journal of petrology, 46/7, 1443– 1487. doi: 10.1093/petrology/egi022 prelević, d., foley, s.f. & cvetković, v. (2007): a review of petrogenesis of mediterranean tertiary lamproites: a perspective from the serbian ultrapotassic province.– geological society of america, special paper, 418, 113–129. doi: 10.1130/2007.2418(06) radulović, a. & erić, v. (1997): karta magmatizma rudnog polja rudnik izveštaj.– geoinsitut, beograd, 19 p. robertson, a.h.f., karamata, s. & šarić, k. (2009): overview of ophiolites and related units in the late palaeozoic–early cenozoic magmatic and tectonic development of tethys in the northern part of the balkan region.– lithos, 108, 1–4, 1–36. schefer s., cvetković, v., fugenschuh, b., kounov, a., ovtcharova, m., schaltegger, u. & schmid, m.s. (2011): cenozoic granitoids in the dinarides of southern serbia: age of intrusion, isotope geochemistry, exhumation history and significance for the geodynamic evolution of the balkan peninsula.– int. j. earth sci. (geol. rundsch.), 100, 5, 1181–1206. doi: 10.1007/s00531-010-0599-x schmid, s.m., bernoulli, d., fugenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine-carpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss j. geosci., 101, 139–183. steiger, r.h. & jäger, e. (1977): subcommission on geochronology: convention on the use of decay constants in geoand cosmochronology.– earth planet. sci. lett., 36, 359–362. doi: 10.1016/0012-821x(77)90060-7 stojanović, j.n., radosavljević, s.a., karanović, lj.c. & cvetković, lj. (2006): mineralogy of w-pb-bi ores from rudnik mt., serbia.– neues jahrbuch für mineralogie – abhandlungen, 182, 299–306. doi: 10.1127/0077-7757/2006/0053 terzić, m. & svešnjikova, e.v. (1991): age of leucite-bearing rocks in yugoslavia.– comptes rendus des seances de la societe de serbe de geol. (1987, 1988 et 1989), 283–287. terzić, m. & terzić, s. (1972): ignimbriti šire oblasti planine rudnika.– vii kongres geologa jugoslavije, zagreb, 2, 359–369. terzić, m. & vukov, m. (1984): prilog petrologiji šumadije daciti slavkovice.– zapisnici srpskog gološkog društva za 1983, 17–23. tošović, r. (1997): morfogenetski tipovi orudnjenja i paragenetske asocijacije u polimetaličnom ležištu rudnik.– magistarska teza, rudarsko-geološki fakultet, 109 p. tošović, r. (2000): genetsko i geološko-ekonomsko modeliranje polimetaličnog ležišta rudnik.– doktorska disertacija, rudarsko-geološki fakultet, 259 p. von quadt, a., ivanov, z. & peytcheva, i. (2001): the central srednogorie (bulgaria) part of the cu (au-mo) belt of europe: a review of the geochronological data and the geodynamical models in the light of the new structural and isotopic studies. – in: piestrzynski, a. (ed.): mineral deposits at the beginning of the 21st century. proceedings of the joint sixth biennial sga-seg meeting, krakow. tokyo: a.a. balkema publishers, 555–558. von quadt, a., moritz, r., peytcheva, i. & heinrich, c. (2005): geochronology and geodynamics of late cretaceous magmatism and cu-au mineralization in the panagyurishte region of the apuseni-banat-timoksrednogorie belt, bulgaria.– ore geology reviews 27, 95–126. doi: 10.1016/j.oregeorev.2005.07.024 vol. 69/1 100 2022 | 75/special issue | 289 | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society dear readers, primary and secondary mineral resources are of strategic importance to the eu economy. the eu has recognized the importance of securing access to mineral resources in the future, meeting the needs of european industry, preserving jobs and ensuring further development. this special issue is dedicated to the mineral potential of south-eastern europe, more specifically the adria region (including the countries of albania, bosnia and herzegovina, croatia, montenegro, north macedonia and serbia), which corresponds to the dinarides, the northwesternmost hellenides, and the vardar zone and has a long history of mining. the five papers, which focus on primary and secondary mine ral resources, are the result of the work of a large team involved in the european institute of innovation and technology (eit)-funded project reseerve – mineral potential of the eastern and south-eastern europe region. mineral potential mapping led to the western balkans mineral register (publicly available data), which enabled the integration of the region into a pan-european mineral information network and brought it closer to the common mineral market. primary raw materials data refers to active, abandoned and closed mines that could be of interest for further exploration / exploitation, as well as prospective greenfield sites. the secondary raw material data include information on mine waste sites (including mining, processing and metallurgical wastes). borojević šoštarić et al. (2022) assessed the main strengths and challenges of the mineral sector in the adria region. they present the status of mineral exploration and exploitation, provide a swot and gap analysis, and developed the roadmap for the necessary actions to promote investments in the mineral sector in the adria region. the potential for discovery and exploitation of primary and secondary mineral resources in montenegro is demonstrated by radusinović et al. (2022), who present the main metallic mineral resources (bauxite, lead and zinc), abundant non-metallic mineral resources (industrial minerals and construction materials) and secondary mineral resources (in particular, aluminous red mud and pb and zn operational and abandoned mine tailings, bottom and fly ash from thermal power plants, slag from steel production, and marlstone and limestone from hanging walls of coal deposits) and waste rock for aggregate production. serafimovski et al. (2022) present an overview and synthesis of several important polymetallic mineral deposits under exploitation in the republic of northern macedonia (copper mine buchim, lead-zinc mines sasa, zletovo and toranica) as well as new exploration targets (plavica, ilovica, kadiica, borov dol). the authors demonstrate the significant polymetallic ore potential in the republic of northern macedonia. steiner et al. (2022) have produced a basic characterization of selected tailings of active and abandoned mines in serbia (bor, porphyry cu/au; krivelj, porphyry cu/au; blagodat, hydrothermal pb-zn; lece, epithermal au; rudnik, hydrothermal/ skarn pb-zn) and north macedonia (sasa, pb-zn; probištip, pbzn; bučim, porphyry cu; lojane, fault-bound vein-type low-temperature as, sb, cr at the contact of rhyolite and serpentinite). primary and secondary resources of the dinarides-hellenides doi: 10.4154/gc.2022.28 they demonstrate the grades of valuable metals that could be recovered to fund potential remediation work and improve the supply of critical metals to the eu. velojić et al. (2022) discuss the significance of trace element analysis from various types of mineralization in the čukaru peki deposit, a recently discovered porphyry high-sulfidation cu-au deposit from eastern serbia. the trace elements study indicates a change in pyrite compositions from porphyrystyle mineralization having a magmatic signature to later highsulfidation mineralization. the manuscripts presented demonstrate the significant potential in primary and secondary resources in the adria region. large reserves of primary commodities, significant secondary potential as a result of decades of mining/metallurgical activities, and numerous active exploration targets including new commodities such as lithium and boron, place the adria region high on the map of eu strategically important areas. however, additional work needs to be done to develop full mineral resource capacity. this includes detailed geological prospection and the standardization of existing geological datasets as well as adjustment and harmonization of the exploration/mining legislation with special plans and education of the next generation of professionals covering the mineral resources life cycle. aside from trained professionals, crucial partners in 21st-century mining are the local communities. social acceptance of future mining operations no longer depends solely on the economic or strategic value of the discovered resources, but also the transparency and community inclusion, wider-society benefits, and sustainability of the presented projects. only projects with the highest environmental standards will gain social acceptance, therefore “green mining” is the new modus operandi of successful exploration and mining companies. references borojević šoštarić, s., giannakopoulou, s., adam, k. & mileusnić, m. (2022): the future of mining in the adria region: current status, swot and gap analysis of the mineral sector.– geol. croat., 75/special issue. doi: 10.4154/ gc.2022.26 radusinović, s., šajn, r., jovanović, b., rokavec, d., hribernik, k., abramović, v., draksler, m., danilović, i. & jovanović, m. (2022): the primary and secondary mineral resources of montenegro and their mapping into european data model.– geol. croat., 75/special issue. doi: 10.4154/ gc.2022.20 serafimovski, s., tasev, g., stafilov, t. (2022) general features of some pollymetallic ore deposits in the republic north macedonia.– geol. croat., 75/special issue. doi: 10.4154/gc.2022.27 steiner, t.m.c., bertrandsson erlandsson, v., šajn, r. & melcher, f. (2022): preliminary chemical and mineralogical characterization of tailing materials from base metal sulfide deposits in serbia and north macedonia.– geol. croat., 75/special issue. doi: 10.4154/gc.2022.22 velojić, m., bertrandsson erlandsson, v., melcher, f., onuk, p., jelenković, r., cvetković, v. (2022): trace elements in pyrite from the čukaru peki porphyry cu–high-sulfidation deposit, serbia: implications for ore evolution in a polyphase hydrothermal system.– geol. croat., 75/special issue. doi: 10.4154/gc.2022.25 sibila borojević šoštarić, guest editor marta mileusnić, guest editor lidija galović, editor-in-chief troskot.indd 123 �geologia croaticageologia croatica ab stra ct the sava depression lies at the very south-western margin of the pannonian basin. there are 20 hydrocarbon fi elds altogether and 17 are still in production. the organic geochemistry data and their statistical analysis from the 25 exploration wells, indicate source rock formations in two stratigraphic levels, an older one of middle miocene age (badenian and sarmatian) and a younger one of upper miocene age (lower pannonian). both source rock formations are composed of marls, calcitic marls, clayey limestones and shales. source rock intervals lay at depths from 1200 to 3362 m. the total organic carbon (toc) of analyzed samples varies from 0.39 to 4.94%, while their total ge nerative hydrocarbon potential is from 2.40 to 37.40 mg hc/g rock. the mean thickness of the intervals is 100–150 m. there is a regular linear increase of the maturity level with depth. source rocks are mature, in the catagenetic phase of transformation that enables hydrocarbon generation. a favourable organic facies, mostly kerogen type ii, (organic facies ab and b), with good hydrocarbon potential, dominates the north-western and central part of the depression. it can be connected with the deeper parts of the depression and/or protected, anoxic to dysoxic stagnant environments with a gradual transition from marine (badenian/ sarmatian) to brackish depositional environments (lower pannonian). in the south-eastern part of the depression, the dominant kerogen type is ii–iii, (organic facies bc), which indicates a stronger infl ux of terrestrial material from the uplifted parts that are generally closer to the margins of the depositional basin. the fisher test (f-test) of the variance similarity (homogeneity), clearly indicates that the badenian/sarmatian samples belong to a statistically different population from the lower pannonian ones, due to their different depositional environments. keywords: sava depression, pannonian basin, croatia, source rock, kerogen type ii, middle miocene, upper miocene, fisher test (f-test), depositional environment comparison of the middle miocene and the upper miocene source rock formations in the sava depression (pannonian basin, croatia) � tamara troskot-čorbić1, josipa velić2 and tomislav malvić2,3 1 geochemistry lab., rock and reservoir fluid research department, corporate processes function, research and development sec., ina-industrija nafte d.d., lovinčićeva bb, 10000 zagreb, croatia; (tamara.troskot-corbic@ina.hr) 2 department of geology and geological engineering, faculty of mining, geology and petroleum engineering, pierottijeva 6, 10000 zagreb, croatia; (josipa.velic@rgn.hr) 3 reservoir engineering and field development sector, exploration and production of oil and gas, ina-industrija nafte d.d., šubićeva 29, 10000 zagreb, croatia; (tomislav.malvic@ina.hr) doi: 10.4154/gc.2009.11 geologia croatica 62/2 123–133 8 figs. zagreb 2009 1. introduction the pannonian basin is mostly a lowland region between the mountain chains of the alps, carpathians and dinarides. its south-western part is in croatian territory, a region that is approximately bordered by the kupa and sava rivers to the south, by the river danube in the east, and by the drava and mura rivers to the north. the sava depression lies at the very south-western margin of the pannonian basin (fig. 1a). two large stratigraphic units are distinguished within the basin. the older (pre-tertiary) complex consists mainly of the palaeozoic igneous and metamorphic rocks, with a subordinate presence of palaeozoic and mesozoic sediments geologia croatica geologia croatica 62/2 124 and okoli (“ž”, “o” and “s” in fig. 1b). the cumulative production from the stružec and žutica fi elds amounts approximately to 35 x 106 m3 of oil, while from the okoli fi eld around 4.5 x 109 m3 of gas have been produced. the fi rst attempt to scientifi cally analyse the geological age and facies of the source rock formations in croatia was undertaken more than 60 years ago (ožegović, 1944). in that paper the sarmatian thin-layered brown bituminous schists found in the gojlo and janja lipa fi elds were identifi ed as “the real source rocks for the earth oil”. the mentioned locations are in the eastern corner of the investigation area delineated in fig. 1b. conclusions in putniković et al. (1989) and radić et al. (1989) refer to the entire croatian part of the pannonian basin. the most important problem treated therein is the correlations between the source rocks and hydrocarbons. based on the 13c/12c isotope ratio, a high source rock-oil correlation has been established. in parallel, results published in alajbeg et al. (1990) stressed the fact that all oils were generated from similar miocene source rocks that comprise one larger group. they originate from the bacterially altered algal material that was to various extents mixed with terrestrial sediments and deposited in the suboxic environment. in the review paper of barić (1996), the summary of results of the geochemical investigations in the croatian part of the pannonian basin concluded that most of the source rocks identifi ed are in the lower to middle miocene formations. in later papers; barić et al. (2000) and with markedly complex structure – folds, faults and metamorphism, together with a pronounced lithologic heterogeneity. a younger complex includes tertiary (mostly neogene) and quaternary rock formations. the most important feature of the sava depression is the sequence of neogene–quaternary sediments, estimated locally at more than 5000 m thickness (velić et al., 2002), in particular in the western part of the depression, south of the moslavačka gora mt. (fig. 1b). this sedimentary sequence is divided into six lithostratigraphic units – formations, with hydrocarbon accumulations documented in fi ve of them. as all of these formations have characteristic lithologic compositions, their superposition is well documented and they are all several hundreds of metres thick. three megacycles were discerned within the sequence (mathur, 1981; velić et al., 2002). each lasted for an approximately equal time span (6.8 ma, 5.9 ma and 5.6 ma) enabling them all to be put into the 3rd order (fig. 2). altogether, there are 20 hydrocarbon fi elds in the sava depression and 17 of them are still in production. they are all concentrated in the north-western part of the depression. the prevailing reservoir rock formations are the pannonian and pontian sandstones, but signifi cant hydrocarbon accumulations have also been discovered in the weathered and fractured palaeozoic igneous and metamorphic rocks. the three most important hydrocarbon fi elds are stružec, žutica fi gu re 1: a) pannonian basin; b) isopach map of the entire neogene to quaternary sequence with hc accumulations, after saftić et al. (2003); c) lndex map of the studied wells in the area of the sava depression, croatia. a bb c geologia croaticatroskot-čorbić et al.: comparison of the middle miocene and the upper miocene source rock formations in the sava depression 125 barić et al. (2003), the miocene petroleum systems are defi ned, wherein the source rocks are badenian to lower pannonian clayey limestones and calcitic marls, lying deeper than 1600 m, and with the prevailing content of kerogen type ii. according to bulk and specifi c parameters, all oils found in the north-western part of the sava depression have a genetic similarity. short migration distances are proposed and the variation in oil characteristics are attributed to post-generative processes, biodegradation, water washing and evaporate fractionation. the purpose here is to illustrate in detail the characteristics of source rocks in the sava depression, based on the most recent laboratory analyses, their geological interpretation and statistical analysis. two source rock formations are identifi ed: badenian with extension into the overlying sarmatian sediments, (older zone – first megacycle) and lower pannonian (younger zone – second megacycle) (fig. 2). it is particularly interesting to investigate the similarities and explain the differences between certain characteristics of these source rocks, e.g. their kerogen and organic facies. they are signifi cant for the changes that took place during the gradual transition from the fi rst, marine megacycle into the second, brackish-freshwater one. the results of geochemical analyses – identifi cation of the source rock formations and estimation of their generative potential have therefore been interpreted in relation to the neogene megacycles. 2. geological setting a more recent reconstruction of the three-phase neogene– quaternary evolution of the pannonian basin was published in lučić et al. (2001) and saftić et al. (2003). the fi rst phase includes the initial structural changes during the oligocene and early miocene with the occurrence of andesite volcanism north of zagreb. the main depositional area was then formed between zagreb, varaždin and ljubljana. in this early extension stage, the sedimentation rate was able to keep pace with basin subsidence, so that all of the depocentres (depressions and sags) were infi lled with syntectonic fi gu re 2: schematic composite stratigraphic column of the north-western part of the sava depression, modifi ed after saftić et al. (2003). geologia croatica geologia croatica 62/2 126 coarseto medium-grained clastics of terrestrial, mostly aquatic origin, with marked lateral facies changes (fig. 2). the third phase is characterised by the main extensional synrift processes that lasted throughout the early and middle miocene (eggenburgian–badenian). it was followed by marine sedimentation and post-rift subsidence during the late miocene when again the infl uence of the sea was diminished and a continental-lacustrine environment was formed. sediment transport into the basin only started to lose pace with the growth of accommodation in the depositional area in the badenian. large deep-sea basins were then formed with deposition of marls and calcitic marls rich in organic matter. subsequently, the sarmatian is characterised by basin starvation, followed by deposition of the condensed sections. sediments that were accumulated in this phase (ottnangian–sarmatian) together make up the 1st megacycle. during the sarmatian–pontian time span, the main extension in the south-western part of the pannonian basin came close to an end, explaining why all upper miocene sediments exhibit common post-rift characteristics. large masses of pannonian and pontian sediments, mostly marls and sandstones were deposited over an extensive area, also covering the former basin margins. this was especially pronounced during pontian times. there was an equilibrium between the rate of basin subsidence and sedimentary infl ux that lasted through the entire pannonian and pontian, resulting in periodic reinstatement of similar depositional environments and formation of a thick sandstone-marl sequence (2nd megacycle) (fig. 2). in the third phase, during the pliocene and quaternary, neotectonic structures were gradually form ed under the infl uence of the north-south oriented regional compressional stress, together with activation of the dextral transcurrent faults and pronounced transpression between the major strike-slip faults. there was also a transition from the continental-aquatic environments to purely terrestrial ones (3rd megacycle). the main structures and hydrocarbon traps were shaped in this late phase (fig. 2). 3. samples and methods organic geochemistry investigations were performed on the samples from cores, side-cores and bit cuttings taken from the 25 exploration wells in the sava depression (fig. 1c). analyses of both the rocks and hydrocarbons, included standard geochemical methods and determination techniques. initially, the petrographic composition of rock samples was determined, together with their sedimentological features, and biostratigraphic allocation of their geological age. the principal parameter in source rock identifi cation is the total organic matter content (% toc). only samples with more than 0.5% toc were taken for further analyses. organic carbon contents were determined by combustion of acid insoluble matter in a leco ir–212 carbon analyser, after treatment with hot 1:1 diluted 36.5% hcl. the powdered rock samples were later subjected to pyrolysis in rock-eval ii+toc and/or rock-eval 6 systems (espitalie et al., 1985). various diagrams to illustrate the obtained parameters (toc, s1, s2, s3, tmax, hi, oi, pi= s1/ (s1+s2) are presented in figs. 3, 4, 6 and 7. instead of the respective source rock intervals their mean depth is used (figs. 3 & 6), and the results are shown with a span between the minimum and maximum values. isolation of organic matter for optical analyses as well as sulphur and stable carbon isotope analyses were undertaken using the conventional hcl/hf/zncl2 procedure. organic matter was examined in transmitted, refl ected and blue fl uorescent light, using an olympus bh–2 and olympus bx– 51 microscope and leitz mpv–3microscope photometer. the mean value of the vitrinite refl ectance was measured. the maceral composition determined is: amorphous organic matter (fl uorescent and non-fl uorescent), liptinite macerals (alginite, sporinite, and liptodetrinite), vitrinite and inertinite. the sulphur content of both the kerogen and bitumen was determined by a leco sc 132 sulphur analyser. analyses of the stable carbon isotopes were carried out in a finnigan mat delta e mass spectrometer according to the procedure outlined in sofer (1980). extractable organic mater (eom) of the powdered rock samples was determined by 36-hr soxhlet extraction with chloroform. extracts were separated by column liquid chromatography into four fractions: saturated hydrocarbons (alkanes), aromatic hydrocarbons, nso-compounds and asphalthenes. gas chromatography analysis of bitumens and of their alkane fractions was performed on a perkin elmer sigma 300 and varian 3900 gc. 4. results and discussion source rock characteristics were discovered at several intervals composed of marls, calcitic marls, clayey limestones, mudstones and shales of middle miocene (badenian and sarmatian) and late miocene (early pannonian) age. the geological age was determined by combining several criteria – superposition, biostratigraphic analyses and their position in relation to the regional e-log marker rs7 which is attributed to have characteristics of a chronohorizon (vrbanac, 2002) (fig. 2). 4.1. source rock based on the results of organic geochemical analyses and organic petrography, source rock intervals were singled out in the drilled columns of 25 exploration wells in the sava depression area. the thickness of these intervals, summarized results of the rock-eval pyrolysis, maceral composition and composition of eom are illustrated in the diagrams for the entire source rock intervals (figs. 3 & 6). middle miocene source rocks (badenian and sarmatian age) are dark, grey to black marls, calcitic marls to laminated clayey limestones, with subordinate intervals of silty marls. source rock intervals were determined at a depth range of 1300–3362 m. total content of organic carbon (toc) in the samples taken from these intervals is between 0.46 and 4.94% toc, with an average of 1.37% (n=234) (fig. 3). in most of the drilled sections, large vertical variations in the total organic content occur, indicating that these geologia croaticatroskot-čorbić et al.: comparison of the middle miocene and the upper miocene source rock formations in the sava depression 127 fi gu re 3: summarized data of the middle miocene source rock intervals – thickness of the intervals; summarized rock-eval pyrolysis data (min and max data for the interval); average maceral composition; eom content and bulk composition (nnw wells of the sava depression marked with red colour; nw wells with green, central group with blue and se wells with yellow). geologia croatica geologia croatica 62/2 128 source rock intervals actually do not represent homogeneous units. it is therefore also natural that the thickness of source rock intervals is highly variable – from 16 to 485 m (242 m on average), but it is most frequently in the 100–200 m range (fig. 3). although it is possible that this apparent inhomogeneity may be caused by results obtained from the bit cuttings (n=205) being non-representative in respect of the resul ts obtained from the cored intervals (n=29), it is predominantly a refl ection of the lithological inhomogeneity. it is noted that the most pronounced variation originates from the increased silty component that correlates well with the reduced content of organic matter and reduced hydrocarbon potential. as a rule, intervals with weak, fair and excellent source rock characteristics are vertically stacked (fig. 3). the total generative hydrocarbon potential determined by the rock-eval pyrolysis (s1+s2) varies from 2.40 to 37.40 mg hc/g rock (fig.3). on average, it is 7.00 mg hc/g rock. the organic facies of source rocks was determined from the obtained values of pyrolytic indices (hi–oi), and is supported by optical investigation of the maceral composition of kerogen. hydrogen index is between 195 and 743, with an average of 398 mg hc/g toc. these hydrogen indices suggest that the most frequent kerogen is type ii (organic facies b (jones, 1987), with a sporadic occurrence of a mixed type i–ii (organic facies ab) (fig. 4). the dominant component of organic matter is fl uorescent amorphous kerogen, (its fl uorescent properties are observable down to the depth of around 3000 m), with a variable proportion of aquatic (alginite, dinofl agellata) and terrestrial lipids (sporinite, liptodetrinite) (fig. 3) (tyson, 1995; taylor et al., 1998), giving this stratigraphic interval attributes of a good oil-prone source rock (hunt, 1995). in most of the specimens an increased quantity of pyrite framboids was observed, indicating the anoxic depositional environment. it was also observed that kerogen has an increased, occasionally very high concentration of total sulphur (up to 11.4%). these parameters connect such types of organic matter with the anoxic and dioxic environments favourable for high preservation of their precursors (demaison & moore, 1980; demaison, 1991). facies of this type dominate in the north-western and central part of the depression. an increased concentration of bitumens also occurs in these source rock intervals (eom from 904 to 7482 ppm, fig. 3). in the samples where the hydrocarbon content is over the limit for the source rocks, secondary migration processes were determined. this migration was controlled by the physical properties of the sediments, i.e. by the fracture systems. the eom content increases in the depth interval from 1800 m to 3000 m. analytical results confi rmed that the bitumens refl ect the characteristics of the determined source rocks and also of their maturity levels. notably, they contain increased amounts of nso-compounds and asphaltene (22.54 to 58.90%, fig. 3) and in the molecular distribution dominate the lighter hydrocarbons. the stable carbon isotope ratios of the analysed kerogens and bitumens vary in a relatively broad range of –21‰ to –28‰ δ13c, which is interpreted as resulting from the facies differences between the source rock intervals (putniković et al., 1989; alajbeg et al., 1990) (fig. 5). in the western part of the depression, these values are up to –25‰ fi gu re 4: modifi ed van krevelen diagram showing kerogen type of the middle and upper miocene source rocks. fi gu re 5: stable carbon isotope data of the middle and upper miocene kerogen and bitumen. geologia croaticatroskot-čorbić et al.: comparison of the middle miocene and the upper miocene source rock formations in the sava depression 129 fi gu re 6: summarized data of the upper miocene source rock intervals – thickness of the intervals; summarized rock-eval pyrolysis data (min and max data for the interval); average maceral composition; eom content and bulk composition (nnw wells of the sava depression marked with red colour; nw wells with green, central group with blue and se wells with yellow). geologia croatica geologia croatica 62/2 130 δ13c. alternatively, the deeper intervals in the south-eastern part of the exploration area of the sava depression have isotope compositions of –28.14‰ δ13c (fig. 5) which indicates their more terrestrial origin as well as more oxic depositional environment. lower values of pyrolytic indices (hi) have also been determined in this south-eastern area. values of hi, especially in relation to depth, are to a certain extent connected with the thermal maturity level, (these rocks are in the oil window, where the lower s2 values are caused by the separation of hydrocarbons from the effective source rock intervals). however, in these intervals they are mostly caused by the increased content of kerogen type iii, in other words the mixed kerogen type ii and iii is present. a stronger terrestrial infl uence has also been confi rmed by the results of the organic petrology investigations. the maceral composition is dominated by non-fl uorescent amorphous kerogen and by the hydrogen-rich liptinite macerals of terrigenous origin (organic facies bc after jones, 1987; figs. 3 & 4). correspondingly, bitumens from these intervals have an increased content of solid paraffi n, a long-chained molecular structure, and highly negative values of isotope composition which indicates their generation from these source rocks. based on the results obtained, it can be concluded that the determined organic facies refl ect the facies differentiation and lateral variations within the badenian–sarmatian sediments. several separate areas with thicker sediments formed within one depositional basin during the badenian. these areas were not only infl uenced by the subsidence of depocentres, but were also formed in the marginal parts of the basin, in areas where marked progradation of new sediments took place (lučić et al., 2001). organic facies of the more favourable kerogen type ii are connected with stagnant, relatively deep-water parts of the basin and anoxic depositional conditions. kerogen type ii–iii occurs in the dysoxic environments closer to the basin margins and is related to faster sedimentation rates and transport of phytoclasts from the land (surrounding uplifts, present day medvednica mt. and moslavačka gora mt.). upper miocene source rocks (early pannonian age) were drilled through at depths between 1250 and 2690 m. the thickness of the source rock intervals is between 19 and 345 m (213 m in average), but most frequently in the range of 100–150 m (fig. 6). these rocks also have a certain level of lithologic inhomogeneity, but they are generally more homogeneous than the older unit and are mostly represented by marls, calcitic marls and clayey limestones. the organic carbon content in these rocks is in the range of 0.39 to 4.15% toc, with an average value of 1.30% (n=259; 199 of these samples are from the bit cuttings and 60 are from cores). the total hydrocarbon generative potential (s1+s2) is between 2.85 and 24.01 mg hc/g rock (fig. 6). the average value is 6.34 mg hc/g rock. measured hi and oi values revealed that the most frequent kerogen is type ii (organic facies b (jones, 1987), but there are also those of a mixed type i–ii (organic facies ab) (fig. 4). hydrogen index values are in the range of 188 to 710, on average 422 mg hc/g toc. the more favourable facies type is mostly developed in the northwestern and central parts of the depression. organic matter is prevailingly amorphous and of algal and bacterially degraded origin (fig. 6) (tyson, 1995; taylor et al., 1998). principal components of organic matter are hydrogen-rich lipids with good generative capabilities that make typical oil-prone source rocks (hunt, 1995). there are local occurrences of variable proportions of the liptinite (terrestrial lipids) and vitrinite macerals. analyses of the carbon isotope composition of kerogen from these intervals indicate δ13cpdb between –24 and –26‰ (fig. 5). total bitumen yield (eom) of these rocks is in the range of 726–8018 ppm (fig. 6). the increased content of eom, based on analytical results, refl ects the characteristics and maturity level of these source rock formations. increased quantities of the nso and asphalthene components (fig. 6) are characteristic for the bitumens generated from the source rocks in the carbonate complex, but also for the maturity level of these intervals. the algal type of organic matter can be observed in the gas chromatographs that are dominated by lighter hydrocarbons. deposition of this type of organic facies is connected with the relatively stagnant, anoxic, often relatively deep, parts of the depression where during the 2nd megacycle the marine environments gradually became transitional, brackish and lacustrine. this was also palaeontologically documented. 4.2. thermal maturity the maturity of the organic matter has been determined based on the pyrolytical (tmax, pi) and optical maturation parameters (tai=thermal alteration index, %ro=vitrinite refl ectance). the maximum temperature of pyrolysis (tmax) is 420–453 °c in the badenian and 420–444 °c in the lower pannonian source rock intervals, and there is an increasing trend with depth (figs. 3 and 6). another trend observed is the increase of pis (s1/s1+s2, fig. 7) starting at a depth of 2400 m (pi over 0.05) and reaching the maximum values (pi=0.5) at approximately 3500 m, which indicates the generation process. since the vitrinite macerals are a secondary component in respect to the prevailing amorphous organic matter, the thermal alteration index (tai) was in most of the wells used as a basis for making estimates of the degree of transformation of organic matter. the relatively smaller number of vitrinite refl ectance measurements was used to confi rm the maturity levels defi ned by the thermal alteration index. vitrinite refl ectance values vary from %ro 0.29 (at 1265 m) to 0.91 (at 3515 m), and are mostly in the oil window range of 0.6– 0.8 %ro. the change of vitrinite refl ectance, (logarithmic scale of the measured %ro values and converted tai–%ro values), with depth is shown in fig. 7. as can be observed, a regular linear increase of maturity with depth has been determined. the thermal alteration of organic matter reached the mature, katagenetic phase that enables hydrocarbon generation (fig. 7). the estimated early stage of the oil window (approx. 0.5 %ro) lies between 2100 and 2200 m, and its end (approx. 1.3 %ro) is at 3600 m (fig. 7). it is therefore congeologia croaticatroskot-čorbić et al.: comparison of the middle miocene and the upper miocene source rock formations in the sava depression 131 cluded that the badenian–sarmatian and lower pannonian source rocks are mature, i.e. that they have reached the conditions for expulsion of hydrocarbons (fig. 7). the only difference is in the intervals that are still to shallow. 4.3. statistical analysis of the maturity level measurements statistical analysis of the maturity level data has been performed on 23 measurements of vitrinite refl ectance. out of this number, 7 samples were taken from the lower pannonian strata and 16 from the badenian and sarmatian rocks. it should be considered that the normal statistical minimum for reliable analysis is an input set of 30 samples (n=30), and this is therefore why the statistics here are only used as an indicator of the statistical parameters of the input dataset. in this way, it is possible to indicate data behaviour regarding their stratigraphic association. such results, in themselves, cannot be interpreted if we consider statistics alone, but they are applied here as a supplement to the main analysis based on data about the source potential measured by laboratory equipment. based on previous experience in the correlation of various geological data, when some were not shown at the same scales, it was decided to calculate two types of correlation. the fi rst was the classical pearson’s linear coeffi cient, while the other was the spearman ranking coeffi cient wherein the values were substituted with their rank, i.e. with values from 1 on. the obtained correlation coeffi cient values are very high, the badenian and sarmatian samples correlation with depth gie a value of 0.91; variance is 0.0257, and the median value 0.52; while the lower pannonian data show a correlation with depth producing a coeffi cient of 0.89; variance of 0.075, and a median value of 0.40 (fig. 8). after the fisher test (f-test) (calculation of variance ratio using f=larger variance/smaller variance), using a null hypothesis that there is fi gu re 7: maturity data – rock-eval pyrolysis maturity data (hi–tmax and pi vs. depth diagrams) and maturity log (%ro & tai converted vs. depth). fi gu re 8: correlation points for the middle miocene and upper mio cene samples. geologia croatica geologia croatica 62/2 132 no difference in population variances had been performed, it was clearly indicated that the badenian/sarmatian samples belong to a population statistically different from the lower pannonian ones. 5. conclusion geological and geochemical investigations of the sediments from 25 exploration wells in the sava depression led to identifi cation and separation of the two source rock intervals and enabled the analysis of their characteristics in terms of the total content of organic matter, its type, quality and maturity level, together with the analysis of their generative potential. a high content of organic carbon was determined in marls, calcitic marls, clayey limestones and shales of middle miocene (badenian and sarmatian) and upper miocene (lower pannonian) age. average toc of source rock formations is 1.37 and 1.30%, respectively. source rock intervals lay at depths of 1200–3362 m. the mean thickness of the intervals is 100–200 m. most of the investigated sediments are the petroleum source rocks with good generative potential. a regular linear increase of maturity with depth was determined. organic matter is in the mature, catagenetic stage of thermal alteration that enables hydrocarbon generation. due to the similarities in organic facies and maturity level, by far the largest infl uence of the generative capabilities of the source rock intervals comes from the content of organic matter. the most pronounced difference that has been determined is actually lateral and within the badenian sediments. in the north-western and central parts of the depression, the organic facies of the analysed stratigraphic units are similar. kerogen type ii (to a lesser extent i–ii) prevails in both units and has ample hydrocarbon potential. the favourable type of organic facies (b to ab) was deposited in the anoxic marine deepwater parts of the basin that were formed during the 1st megacycle. in the pannonian (2nd megacycle), the continuation of sedimentation of similar facies types has been preserved in the deeper parts of the depression, and in the protected and undisturbed environments with a gradual transition from the marine basin into the brackish and lacustrine environments. in the south-eastern part of depression a somewhat different situation occurred, where within the deeper intervals of the badenian source rock formations the mixed kerogen type ii and iii (organic facies bc) has been determined. it originates from environments with a larger sedimentary infl ux (of terrigenous lipids and phytoclasts) from the land (medvednica mt. and moslavačka gora mt.), indicating the presence of dysoxic environments that were generally located closer to the margins of the depositional basin. acknowledgements this research was supported by ina-industrija nafte d.d. we would like to thank josip križ, director of the exploration sector and msc. željko ivković for permission to use data published in this paper. the authors are grateful to employees of the geochemical laboratory for all technical support. we are thankful to the reviewers; prof. dr. istvan berczi and dr. katalin milota, for their supportive comments and suggestions that helped improve the manuscript. this work also represents part of a multidisciplinary geological investigation that was performed in 2008 and 2009 within the project entitled “stratigraphical and geomathematical researches of petroleum geological systems in croatia” project no. 195-1951293-0237, which was fi nanced by the ministry of science, education and sports of the republic of croatia. references alajbeg, a., britvić, v., švel-cerovečki, s., cornford, c., todorić, a., rajković, j., barić, g. & putniković, a. (1990): geochemical study of the oils and source rocks in the pannonian basin.– org. geoch., 16, 339–352. barić, g. (1996): organic geochemistry in the rationalization of oil and gas exploration and production.– geol. croat., 49/2, 191–195. barić, g., ivković, ž. & perica, r. (2000): the miocene petroleum system of the sava depression, croatia.– petr. geosci., 6, 165–173. barić, g., tari, v. & ivković, ž. (2003): petroleum systems in the southern part of the pannonian basin and in the adriatic offshore, croatia.– nafta, 54/7–8, 299–307. demaison, g.j. & moore, g.t. (1980): anoxic environments and oil source bed genesis.– amer. assoc. petrol. geol. bull., 64, 1179–1209. demaison, g.j. (1991): anoxia vs productivity: what controls the formation of organic-carbon-rich sediments and sedimetary rocks?– amer. assoc. petrol. geol. bull., 61, 1950–1961. espitalie, j., deroo, g. & marquis, f. (1985): rock eval pyrolysis and its aplications.– institut francais du petrole, geologie no. 27299, project b41 79008, paris, 72 p. hunt, j.m. (1995): petroleum geochemistry and geology.– w.h. freeman and company, san francisco, 743 p. jones, r.w. (1987): organic facies.– in: brooks, j. & welte, d. (eds.): advances in petroleum geochemistry 2. academic press, london, 1–90. lučić, d., saftić, b., krizmanić, k., prelogović, e., britvić, v., mesić, i. & tadej, j. (2001): the neogene evolution and hydrocarbon potential of the pannonian basin in croatia.– mar. petr. geol., 18, 133–147. mathur, s.m. (1981): cyclic sedimentation in the vindhyan supergrup.– geological survey of india, records, 112, viii, 1–6. ožegović, f. (1944): prilog geologiji mlađeg tercijara na temelju podataka iz novijih bušotina u hrvatskoj [contribution to the late tertiary geology – data from the newest wells in croatia – in croatian].– geol. vjesnik, 2–3, 391–491. putniković, a., britvić, v., dragaš, m. & majstorović, j. (1989): geološka interpretacija i usporedba geokemijskih podataka u svrhu sagledavanja međusobne povezanosti matičnih stijena i ugljikovodika u panonskom bazenu [geological interpretation and comparison of the geochemical data in a sense of source rockhydrocarbon correlation, pannonian basin – in croatian]. – dit ina-naftaplin, 26–27, 87–94. radić, j., britvić, v. & dragaš, m. (1989): matične stijene panonskog bazena – istražno područje ina-naftaplin [source rocks of the pannonian basin – exploaration area of ina-naftaplin – in croatian].– dit ina-naftaplin, 26–27, 77–85. saftić, b., velić, j., sztanó, o., juhász, g. & ivković, ž. (2003): tertiary subsurface facies, source rocks and hydrocarbon reservoirs in the sw part of the pannonian basin (northern croatia and south-western hungary).– geol. croat., 56/1, 101–122. sofer, z. (1980): preparation of carbon dioxide for stable carbon isotope analysis of petroleum fractions.– anal. chem., 52, 1389–1391. taylor, g.h., teichmüller, m., davis, a., diessel, c.f.k., littke, r. & robert, p. (1998): organic petrology.– gebrüder borntraeger, berlin-stuttgart, 704 p. geologia croaticatroskot-čorbić et al.: comparison of the middle miocene and the upper miocene source rock formations in the sava depression 133 tyson, r.v. (1995): sedimentary organic matter – organic facies and palynofacies.– chapman & hall, london-gasgow-winheim-new york-tokyo-melbourne-madras, 615 p. velić, j., weisser, m., saftić, b., vrbanac, b. & ivković, ž. (2002):petroleum-geological characteristics and exploration level of the three neogene depositional megacycles in the croatian part of the pannonian basin.– nafta, 53/6–7, 239–249. vrbanac, b. (2002): contribution to the debate on the stratigraphyc classifi cation system and the importance of ek-markers in the sava depression.– nafta, 53/1, 39–44. manuscript received february 05, 2009 revised manuscript accepted june 08, 2009 available online june 19, 2009 www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society article history: manuscript recieved: may 8, 2024 revised manuscript accepted: may 28, 2024 available online: june 21, 2024 keywords: fracture network, carbonate aquifer, digital outcrop model, discrete fracture network modelling, northern croatia 2024 | 77/2 | 99–125 | 12 figs. | 1 tab. | 4 suppl. figs. | 9 suppl. tabs. | 1. introduction groundwater represents a strategic resource since it provides approximately half of the global volume of water withdrawn for domestic use and approximately one-fourth of the water for irrigation (united nations, 2022). valuable groundwater resources are hosted in fractured bedrock aquifers (e.g., singhal & gupta, 2010). it has been estimated that 10% of the world population relies on freshwater from carbonate aquifers (stevanović, 2019). this importance increases in the mediterranean region where the karst groundwaterdependent ecosystems are extensively used, facing environmen tal threats (siegel et al., 2023). site-specific management plans considering both the principal flow paths and the hydraulic properties of the aquifer are crucial for a more efficient conservation of groundwater resources. in rocks having low primary porosity and permeability, the bulk hydraulic properties are controlled by the network of fractures crosscutting the rock mass (singhal & gupta, hydrogeological parameterisation of the daruvar thermal aquifer: integration of fracture network analysis and well testing ivan kosović1, bojan matoš2,*, stefano casiraghi3, gabriele benedetti3, tihomir frangen1, kosta urumović1, ivica pavičić2, andrea bistacchi3, silvia mittempergher3, marco pola1 and staša borović1 1 croatian geological survey, department of hydrogeology and engineering geology, sachsova 2, 10000 zagreb, croatia 2 university of zagreb, faculty of mining, geology and petroleum engineering, department of geology and geological engineering, pierottijeva 6, 10000 zagreb, croatia; (*corresponding author: bojan.matos@rgn.unizg.hr) 3 università degli studi di milano bicocca, dipartimento di scienze dell'ambiente e della terra, piazza della scienza, 4, 20126 milan, italy doi: 10.4154/gc.2024.11 abstract highly fractured mesozoic carbonate rocks are the main reservoir of many geothermal resources in northern croatia, being of environmental, cultural, and economic value for the local and regional communities. the daruvar thermal springs (temperatures < 50°c) represent the outflow area of an intermediate scale, tectonically controlled, hydrothermal system hosted in triassic carbonate rocks. several investigations have been conducted in the daruvar area detailing the architecture of regional and local fracture networks and quantifying the hydrogeological parameters of the thermal aquifer. in this work, an integrated approach based on structural and hydrogeological investigations was employed to model the network of fractures in the reservoir and quantify its impact on the hydraulic properties. structural investigations were conducted in the batinjska rijeka quarry, considered as an outcrop analogue of the thermal aquifer, employing both a classical field approach and the virtual quantitative analysis of a 3d digital outcrop model. structural analysis of the digital outcrop model allowed identification of two sub-vertical systems of discontinuities, dipping to the nw and the wsw respectively, in accordance with the data collected through direct field measurements. the main geometric features of the discontinuity network and their statistical distributions were employed to construct discrete fracture network models at both the outcrop scale (approximately 100 m) and the aquifer scale in daruvar (approximately 700 m). calibration of the input parameters allowed modelling of porosity and permeability values that reproduce the field values assessed through pumping tests, well tests, and well logging. this work highlights the importance of integrating geological and hydrogeological investigations to obtain a more reliable reconstruction and quantification of the processes driving the fluid flow in fractured aquifers and affecting the spatial distribution of their hydraulic properties. 2010). for fractures here we consider every kind of dis con tinuity including bedding discontinuities, schistosity, joints, shear fractures, veins, stylolites and other dissolution features, deformation and compaction bands, etc. (e.g., bistacchi et al., 2020; storti et al., 2022). the permeability field in the rock mass depends on the geometric features of the fractures (i.e., orientation, intensity, aperture, length, etc.) and the connectivity of the fracture network (e.g., faybishenko et al., 2000; de dreuzy et al., 2001, 2002). fault zones affect the groundwater circulation at both regional and local scales, primarily influencing the development of springs in hard rock terrains (e.g., keegan-treloar et al., 2022). the wellestablished conceptual model of fault zones generally includes a low permeable fault core surrounded by a highly fractured and permeable damage zone (e.g., caine et al., 1996; faulkner et al., 2010), although different hydraulic behaviours are documented (i.e., high permeability fault core; smith et al., 2013). the structural architecture of fault zones and the impact of fracture networks on the permeability field mailto:bojan.matos@rgn.unizg.hr g eo lo gi a c ro at ic a 100 geologia croatica 77/2 have been extensively investigated using both structural and hydrogeological approaches. still, the integration between these two disciplines is limited due to different methods and scales of investigation (e.g., bense et al., 2013). outcrop geological and structural mapping supported by numerical modelling and pumping tests are the most common approaches to quantify the permeability of fractured aquifers in the field (singhal & gupta, 2010; bense et al., 2013). outcrop characterisation determines the main kinematic, chronological, and geometric features of the fracture network and the statistical distribution of fracture parameters. the classical field investigations can be supported by photogrammetric reconstruction of the outcrop. this technique can be used to investigate extensive outcrops, which may not even be accessible in field investigations, obtaining large datasets for a solid statistical analysis of the main discontinuity sets through the virtual structural analysis of the digital outcrop model (e.g., hodgetts, 2013; bistacchi et al., 2015; martinelli et al., 2020). these statistical distributions can be used to stochastically reconstruct the fracture network, employing the discrete fracture network (dfn) approach. considering each fracture as a discrete object with peculiar hydraulic properties surrounded by an impermeable matrix, dfn models are profitably used to determine the permeability of fractured aquifers and rock masses (e.g., voeckler & allen, 2012; lei et al., 2017; medici et al., 2020; ceccato et al., 2021; smeraglia et al., 2021; mammoliti et al., 2023; medici et al., 2023). however, calibrations and uncertainty analysis of parameters (particularly aperture) with permeability values from field investigations are generally lacking. pumping tests consist of pumping groundwater from a well at different flow rates and measuring the drawdown in observation wells. the hydraulic properties (mostly transmissivity and hydraulic conductivity) of the aquifer are assessed by modelling the variations of the drawdown using analytical solutions (e.g., kruseman et al., 2000). due to the heterogeneous structure of fractured aquifers, the identification of flow-bearing paths is crucial for assessing the most suitable modelling approach (e.g., carrera & martinez-landa, 2000; guihéneuf et al., 2021), as well as for understanding and managing the site. in contrast, hydrogeological investigations through pumping and well tests generally focus on assessing the hydrogeological properties of the aquifer and the efficiency of the tested well, but they generally lack insights into the fracture network architecture. among groundwater resources in fractured aquifers, geothermal resources are particularly important since they are potential renewable sources of raw materials and energy (e.g., finster et al., 2015; szanyi et al., 2023). geothermal resources generally have a lower yield and higher management costs than groundwater resources. therefore, assessing the hydraulic characteristics of the reservoir and the impact of regional and local fracture systems is crucial for the quantification of the renewable component of the system and the proposal of management plans for long-term sustainable exploitation (e.g., rybach & mongillo, 2006). northern croatia is rich in thermal springs that are mostly used for balneotherapy and tourism (borović & marković, 2015). here, connected geothermal resources have great potential since they share the favourable thermal features of the pannonian area (horváth et al., 2015). the thermal spring area in daruvar city (figs. 1 and 2) is one of the most investigated thermal regions in croatia (e.g., borović, 2015; borović et al., 2019; kosović et al., 2023; urumović et al., 2023; kosović et al., 2024). thermal springs in daruvar (temperature up to 50°c; fig. 3) have been documented since the roman era, representing an economic and cultural value for the area. the daruvar thermal field is the outflow area of an intermediate scale geothermal system hosted in a mesozoic fractured carbonate reservoir. previous studies investigated the hydraulic properties of the reservoir and the architecture of regional and local fracture systems (e.g., borović et al., 2019; kosović et al., 2024). in this work, an integrated approach combining structural data analysis and well testing is applied to detail the hydraulic properties of the daruvar thermal aquifer. structural investigations were conducted in the batinjska rijeka quarry (brq; fig. 2) located 4 km ne of daruvar. there, the mesozoic carbonate rock complex is highly fractured representing an outcrop analogue of the aquifer. the discontinuities deforming the rock mass were investigated through both classical field investigations and the analysis of the digital outcrop model (dom) of the quarry. a dfn model reproducing the observed network of discontinuities was constructed, and its capability of assessing the hydraulic properties of the aquifer was tested using data collected from several well tests and logs conducted in the daruvar thermal field. 2. geological and hydrogeological settings 2.1. regional tectono-structural evolution the study area is located along the western margin of mount papuk, which is part of the slavonian mts. (fig. 1). the slavonian mts. are the best exposures of the tisza continental block, i.e., a lithospheric fragment of the european foreland that formed beside the adria microplate during the middle jurassic (fig. 1; schmid et al., 2008). the polyphasic tectonometamorphic evolution of the study area started with the variscan and continued with the alpine-dinarides-carpathian orogeny. the continuous convergence between the tisza-dacia mega block, the adria microplate, and the european plate through the late mesozoic-cenozoic caused the stacking of the mecsek, bihor, and codru nappe systems (balen et al., 2006; schmid et al., 2008). the slavonian mts. are part of the bihor nappe system that also crops out in southern hungary. their structural architecture was significantly influenced by the proximity of the sava suture zone (fig. 1), which resembled the cretaceous-palaeogene regional suture zone between the tisza block toward the ne and the adria microplate block toward the sw (schmid et al., 2020). furthermore, regional fault zones such as the periadriatic lineament and the mid-hungarian fault line (fig. 1) played important roles as tectonic boundaries between the main regional blocks accommodating the clockwise rotation of the tisza-dacia mega block, the counterclockwise rotation of the adria plate, and the eastward lateral extrusion, at a scale of several hundreds of km (fig. 1; prelogović et g eologia c roatica 101kosović et al.: hydrogeological parameterisation of the daruvar thermal aquifer: integration of fracture network analysis and well testing al., 1998; tari et al., 1999; csontos & vörös, 2004; ustaszewski et al., 2010) after the climax of cretaceous-palaeogene tectonism, the opening of the pannonian basin system (pbs) between the carpathians and the dinarides occurred (balen et al., 2006). the tectonic evolution of the pbs was characterised by polyphase extension, compression, and tectonic inversion. formed by early-middle miocene ne-sw oriented back-arc type lithospheric extension, the pbs was characterised by systems of nw-se striking normal faults that formed rift and wrench-type troughs filled with large amounts of syn-rift deposits (horváth et al., 2006; ustaszewski et al., 2010). these basins and correlative structural highs were subjected to localised tectonic inversion during the middle miocene, but deepening and rapid thermal subsidence along existing ne-sw and nw-se striking faults prevailed until the early pliocene (tomljenović & csontos, 2001; malvić & cvetković, 2013). changes in the stress field due to the counterclockwise rotation of the adria microplate and the consumption of the subducted european plate yielded a transition from extension to n-s compression/transpression, which resulted in regional tectonic inversion and fault reactivation (bada et al., 2007; ustaszewski et al., 2014). the pliocene-quaternary tectonic inversion accommodated regional folding and prevalent reverse and strike-slip faulting (jarosinski et al., 2011). it yielded the uplift of the basement structural highs (e.g., slavonian mts.), the tectonic inversion of pre-existing basement structures and the formation of strike-slip fault-related positive f lower structures (prelogović et al., 1998; tomljenović & csontos, 2001). 2.2. geological and structural setting of the study area the geological setting of the nw part of the slavonian mts. was investigated by jamičić et al. (1989). due to its complexity, the lithological units of the study area (fig. 2) were figure 1. regional tectonic map of the alps, dinarides, tisza-dacia mega block, and the european foreland framework (after schmid et al., 2008, 2020). the map shows the principal regional faults and the outline of the neogene basins (black line) including the pannonian basin. the principal towns and the neighbouring states are depicted (acronyms: aut – austria, bih – bosnia and herzegovina, hrv – croatia, hun – hungary, ita – italy, slo – slovenia, srb – serbia). g eo lo gi a c ro at ic a 102 geologia croatica 77/2 reorganised by kosović et al. (2024) as follows: i) prepermian crystalline rocks, ii) permian sedimentary units, iii) triassic carbonate complex, iv) jurassic limestones, v) miocene sedimentary and magmatic rock complex, vi) pliocene clastic sediments, vii) pleistocene unconsolidated sediments, and viii) holocene alluvial and colluvial unconsolidated sediments. the pre-permian crystalline basement extends across a large surface area in western papuk (fig. 2), encompassing magmatic and metamorphic rock complexes that are partly transgressively covered by younger units (jamičić et al., 1989; pamić et al., 2003). the onset of the permian succession began with transgressive, welllayered conglomerates and quartz sandstones. triassic and jurassic formations constitute the mesozoic carbonate rock complex that represents the main reservoir of the daruvar thermal waters. the triassic succession is characterised by lower to middle triassic clastic deposits (e.g., sandstones, siltstones, and laminated shales) sedimented within a shallowwater environment (jamičić et al., 1989; šikić, 1981). a gradual transition towards carbonates (e.g., dolomites, limestones, and crinoid limestones with chert) is observed in the middle to late triassic, while the late triassic stratigraphic top is characterised by a pure dolomite-limestone succession (occasionally incorporating dolomite and limestone breccias and marly limestones; fig. 2). in a sequence, jurassic deposits are observed being represented by grey platy limestones with cherts. the cretaceous collision between the tisza block and the adria and europe plates caused emersion in the slavonian mts. sedimentation was partly restored during the middle miocene e-w regional extension of the pbs. it continued through the late miocene-pliocene and quaternary (fig. 2), characterised by a transition from coastal to freshwater depositional environments (saftić et al., 2003). the youngest sediments are quaternary unconsolidated sediments (from figure 2. simplified geological map of the daruvar area and lithostratigraphic succession (modified from kosović et al., 2024). the black polygon represents the extent of fig. 4a. topographic peaks are denoted by white triangles, while the main towns are shown as teal polygons. the nw-se striking geological profile (bottom) depicts the general structural relationships along the western margin of mount papuk, in the vicinity of the batinjska rijeka quarry (brq). fault acronyms: bof – borki fault; df – daruvar fault; def – dežanovac fault; gf – gradina fault; pf – pakrac fault; tf – toplica fault. g eologia c roatica 103kosović et al.: hydrogeological parameterisation of the daruvar thermal aquifer: integration of fracture network analysis and well testing sandy gravels to sandy clays), deposited by alluvial and gravitational processes (jamičić et al., 1989). the cretaceous to quaternary tectonic evolution of the study area is affected by the structural architecture of the slavonian mts. and the surrounding basins (kosović et al., 2024). the complex structural pattern of generally e-w striking thrust faults (i.e., voćin fault, gradina fault, dežanovac fault, and daruvar fault; fig. 2) and multi-folded structures gently dipping towards both the nnw and sse or ene and wsw suggests a polyphase evolution, which began with regional cretaceous-palaeogene e-w contraction. this contraction formed an initial nw-se striking fault and nnw and sse dipping fold pattern, which rotated counterclockwise approximately 40° towards the ne during the palaeogene (tomljenović & csontos, 2001; ustaszewski et al., 2008). counterclockwise regional rotation resulted in the final structural emplacement of the existing faults and folds, reoriented as e-w striking thrust faults and an ene and wsw dipping fold system. though the neogene was characterized by regional e-w extension and the formation of predominantly normal faults, inherited faults/fold systems in the study area experienced only partial tectonic stretching and gravitational sliding. contemporary, sediment deposition within preexisting synclines occurred (fig. 2; (jamičić, 1995; tari et al., 1999; tomljenović & csontos, 2001). the pliocenequaternary regional n-s compression/transpression promoted continuous shortening and re-folding processes of the preexisting structures coeval with the formation of dextral/ sinistral faults (e.g., toplica fault; tf in fig. 2), which locally displaced existing e-w striking thrust faults. 2.3. hydrogeological setting of the daruvar thermal system the lithostratigraphic sequence in the daruvar thermal area (kosović et al., 2023) was assessed through boreholes and wells: i) quaternary alluvial deposits, ii) miocene or pliocene marls, iii) miocene bioclastic limestone, and iv) triassic dolomites and limestones with an investigated thickness of 130 m. core analyses and well logging evidenced that the triassic carbonates are characterised by a uniform background fracture network and by localised corridors (total thickness of 24 m in the deepest well), showing a higher frequency of fractures. the thermal waters are hosted in fractured triassic carbonate rocks, and subthermal waters can be found in the sandy layers of the alluvial cover and the miocene biocalcarenites (borović et al., 2019). the aquifer transmissivity assessed through pumping and well tests ranges from 0.015 to 0.03 m2/s (borović et al., 2019; urumović et al., 2023), while the average porosity measured through neutron borehole logging is 7.9%. hydrochemical and isotope analyses of the thermal waters (borović, 2015) evidenced: i) a temperature from 18.2 to 49.8°c, nearly-neutral ph, and electrical conductivity of 550–700 μs/cm, ii) a calcium-bicarbonate hydrochemical facies indicating flow through a carbonate aquifer, iii) the meteoric origin of the water as depicted by o and h stable isotope ratios, iv) a reservoir equilibrium temperature of 80°c calculated using sio2 geothermometers, and v) a mean residence time between 11 and 15 ka assessed through 14c activity. these data, combined with the results of regional and local scale structural and geophysical investigations, were used to propose a conceptual model of the daruvar hydrothermal system (borović et al., 2019; kosović et al., 2024). the recharge area of the system is located in the topographically higher petrov vrh, approximately 8 km e of daruvar (fig. 2). here, mesozoic carbonate rocks extensively crop out and are deformed by n-s and e-w striking fractures that are potential paths for the infiltration of the meteoric waters (kosović et al., 2024). the general westward dip of the strata and e-w tensional open fractures favour the westward flow of the infiltrated waters in the mesozoic reservoir. the waters are warmed to 80°c by the regional heat flow and convection processes in the aquifer. in the daruvar area, they intercept an asymmetric anticline cogenetic to the daruvar reverse fault (df in fig. 2). the fold is structurally reactivated by the regional polyphase tectonic evolution, increasing the fracturing of the bedrock. the thermal waters rise to shallow depths in the damage zone of the daruvar fault and the fracture network in the hinge of the daruvar anticline. the fold hinge could be affected by a local extensional regime increasing both the aperture of the fractures and the permeability field of the aquifer. the main outflow occurs within the interaction zone of local scale faults/fractures mapped through geophysical investigations (kosović et al., 2023). this structure further localises the flow of the thermal waters resulting in four thermal springs (fig. 3) with temperatures between 38 and 50°c. currently, the thermal waters are exploited from a well and two springs providing approximately 10 l/s. 3. methods 3.1. structural-geological investigations and analysis geological field investigations were carried out from 2021 to 2023. structural and geological data were collected ne of daruvar in the batinjska rijeka quarry (brq) and the surrounding area (fig. 2). this area was selected as it provides an extensive outcrop of the mesozoic carbonate rock complex and it can be considered as an outcrop analogue of the daruvar thermal aquifer. data were collected at 59 locations and were spatially georeferenced using gis software (fig. 4a). structural measurements included dip direction and dip angle of bedding, fractures, and faults. for faults, lineation and sense of slip, i.e. striations and slickenside orientations with their sense of movement, were also recorded. the resulting cumulative dataset incorporated 109, 284, and 50 measurements of bedding, fractures, and faults, respectively. for the structural data analysis, the software stereonet v.11 was used to plot bedding and fracture/joint data (allmen dinger et al., 2011; cardozo & allmendinger, 2013). determination of the most representative fracture sets was conducted by plotting the poles of fracture planes and constructing the contour plots of the poles’ distribution using the 1% area contour method (allmendinger et al., 2011; cardozo & allmendinger, 2013). fault planes and shear planes were used to determine the palaeostress field based on the geometric properties of the fault and its kinematics g eo lo gi a c ro at ic a 104 geologia croatica 77/2 (doblas, 1998). based on kinematic criteria, the fault data were analysed by the software win-tensor v. 5.9.2 and tectonicsfp v. 1.7.9 (ortner et al., 2002; delvaux & sperner, 2003). fault data were separated into compatible fault groups, and theoretical maximum (σ1), mean (σ2), and minimum stress axes (σ3) were calculated using the p–t axis method (turner, 1953; marrett & allmendinger, 1990). the palaeostress field was analysed by constructing the synthetic focal mechanisms for each fault group using the right dihedra method (angelier & mechler, 1977). 3.2. digital structural analysis and dfn modelling the reconstruction of the network of discontinuities for quantifying the hydraulic parameters of the aquifer analogue was conducted through: i) imaging of the brq obtaining a 3d digital outcrop model (dom) of the quarry, ii) digital structural analysis of the dom reconstructing the main systems of discontinuities (i.e., both bedding and fractures), iii) statistical analysis of the main geometrical parameters of the systems, and iv) discrete fracture network (dfn) modelling of the discontinuity network for the hydraulic parameterisation. the imaging of brq was performed in april 2023 using dji matrice 300 rtk unmanned aerial vehicle (uav). the uav was equipped with a zenmuse p1 camera featuring a resolution of 45 megapixels, a full-frame size sensor, and a 35 mm focal length lens. the location of the uav was determined with centimetre accuracy during the whole flight using the rtk (real-time kinematics) method and employing a supplementary gnss device on a fixed position. due to the complex quarry geometry, manual flying was used to control the uav while capturing images resulting in a camera-wall distance of 15 to 65 m. 702 images were acquired with an image overlap up to of 90%. they were processed into a 3d dom of the quarry (fig. 4b) by means of “structure from motion” algorithms using the photogrammetry software pix4dmapper v. 4.7.5 (url 2). the resulting dom was in sub-centimetre resolution (0.29-0.56 px/cm) covering a surface of 222,135 m2. the software cloudcompare v. 2.13.0 (url 3) was employed for the digital structural analysis of the dom. sections of the walls (qs2-qs6; fig. 4b), where discontinuity sets were more visible, were selected for analysis. discontinuity figure 3. map of the daruvar thermal field area showing the thermal springs (blue dots) and the main wells and exploration boreholes (red circle). figure 4. (a) investigated area of the batinjska rijeka quarry (brq; image source: url 1) with main faults (acronyms in fig. 2). observations (purple points) were conducted within the quarry area and its surroundings. (b) digital outcrop model of the brq showing the sections (polygons) used for the digital structural analysis of the discontinuity systems. the section qs3a (red polygon) was chosen to detail the length of the main sets of discontinuities being the base for the dfn modelling. g eologia c roatica 105kosović et al.: hydrogeological parameterisation of the daruvar thermal aquifer: integration of fracture network analysis and well testing mapping was done employing the manual sampling technique “trace tool” of the plugin compass in the cloudcompare software (thiele et al., 2017). this tool was used for the manual selection of the dom’s points that belong to a discontinuity surface and for the calculation of the 3d plane that best fits the points’ selection. the dip direction and dip of the discontinuity were calculated from the fitted plane. the software stereonet v.11 (allmendinger et al., 2011; cardozo & allmendinger, 2013) was used to determine the most representative sets of discontinuities in each section of the quarry following the methodology described in the field structural investigations. the analysis of the dom showed that the rock mass in level 3 of the quarry was highly fractured. therefore, the qs3a (fig. 4b) was selected to detail the geometric analysis of the discontinuity sets, since it is the longest section in level 3 and has the greatest amount of data. the domstudioorientation script (url 4) for clustering analysis and fisher concentration parameter calculations were used to separate and assess the statistics of the main sets of discontinuities. the code was run using the software matlab v. 9.11.0 (url 5). a 2d front-view orthophotograph of the qs3a outcrop was performed and imported into the software qgis v. 3.34.5 (url 6) to manually vectorise the 2d traces of the discontinuities. the traces were used to: i) calculate the areal fracture intensity p21 (length of fractures over area) for each discontinuity set, and ii) assess the statistical distribution of the heights of the sets in the outcrop using the fracability package (url 7), which allows fitting a statistical distribution to length data affected by censoring bias due to the finite size of the outcrops by applying survival analysis (benedetti et al., 2024). the data obtained from the structural analyses of the dom and the qs3a section were used to build the dfn model of the investigated outcrop. the input parameters for each set of discontinuities were: mean dip, mean dip direction, fisher k, mean length, standard deviation of length, length/height ratio, volumetric fracture density p32 (area of fractures over volume), and aperture. all parameters were determined from the previous analyses except for p32 and aperture, which were calibrated through the dfn modelling. p32 cannot be directly measured and needs to be estimated from p21. a linear relationship is expected between p21 and p32 for domains with similar properties (dershowitz & herda, 1992; mauldon, 1994; wang, 2005): p32 c21*p21= (1) here, p32 was calibrated using the dfnworks python package (hyman et al., 2015) with a procedure similar to that described in antonellini et al. (2014), korneva et al. (2015) and zambrano et al. (2016). for each discontinuity set, it is necessary to target at least 3 different increasing p32 and run simulations for each target. the resulting dfn is sliced along the reference outcrop’s mean plane to calculate the corresponding p21 value. the overall mean of the p21 values is the simulated value for the chosen target p32. at the end of each calibration procedure, it is possible to calculate the theoretical linear relationship of the p32/p21 ratio for each fracture set in a given homogeneous volume. this calibrated linear coefficient c21 can be then used to obtain the p32 value corresponding to the p21 measured on the dom. the calibration of the aperture and the calculation of the distributions of porosity (φ) and permeability (k) were conducted employing the software petroleum experts move v. 2019.1 (url 8). this software has been profitably used to calculate the k field of fault zones in fractured carbonates (antonellini et al., 2014; korneva et al., 2015; zambrano et al., 2016; giuffrida et al., 2019; romano et al., 2020; smeraglia et al., 2021; mammoliti et al., 2023). different approaches used by the software to assign the aperture to the discontinuity were tested. they consist of: i) a constant aperture, ii) an aperture proportional to the root length of the fracture, and iii) an aperture proportional to the length of the fracture. the proportionality constant in the second and third approaches is calculated by the software inputting the average aperture of the fracture set. the software discretises the modelling domain using a grid (i.e., geocellular volume), and then the φ and the k tensor of the cell are computed. the φ is obtained as the ratio between the total fracture volume in the cell and the cell volume, while the k tensor calculation is based on the geometric methodology described by oda (1985). 3.3. hydrogeological parameterisation the hydrogeological parameterisation of the thermal aquifer was performed by analysing the results of a pumping test conducted on 27 february 2022 in daruvar. the water was pumped from the well dar 1 at different flow rates (q). the water level variation was measured in the wells dar 1, d 1, and ds 1 and in the spring antunovo vrelo (fig. 3) using a hobo water level data logger with a range of 9 m. the resolution of the water level measurement was 1 cm, while the temporal interval between the measurements was 60 s in dar 1 and 10 s in the other objects. manual measurements of the water level were conducted to constrain the measured data. the flow rate was measured at least three times during every single step. the results of this test are partially reported in urumović et al. (2023) where part of the dataset measured in dar 1 was used to develop a new methodology for interpreting stepdrawdown well tests. in this study, a double approach was used: i) the dataset was interpreted as a pumping test (i.e., exploitation and observation well), and ii) the data collected in dar 1 were reinterpreted using the classical approach for interpreting step-drawdown well tests. since the daruvar thermal aquifer is highly fractured, it can be considered as a quasi-homogenous porous medium at the investigated scale. the aquifer is confined because the water level is generally a few metres below the ground while the top of the aquifer is at least 5 m below the ground level. therefore, the theis-hantush analytical solution (theis, 1935; hantush, 1961a, b) for pumping tests in nonleaky confined aquifers was applied. the analysis of the collected data was performed using the software aqtesolv v. 4.5 (duffield, 2007). it consisted of manually matching the theis-type curve to the drawdown (δ) plotted as a function of time on double logarithmic axes. afterward, the software optimised the curve through a nonlinear weighted leastg eo lo gi a c ro at ic a 106 geologia croatica 77/2 squares parameter estimation, employing the gauss-newton linearisation method procedure. the estimated parameters were the transmissivity (t), the storativity (s), the hydraulic conductivity anisotropy ratio (kz/kr), and the saturated thickness (b). besides the pumping test analysis, the data collected in dar 1 were further investigated as a step-drawdown well test. details on the interpretations of well tests can be found in (kruseman et al., 2000). the collected data were used to determine the theoretical drawdown vs. flow rate curve of the well, the well efficiency (w), and its specific capacity (sc = q/δ). the specific capacity can be in turn used to determine the t of the aquifer using experimental relationships: 2 1.07t (m /day) = 0.85*sc (2) 2 1.07t (m /s) = 2.39*sc (3) these equations were considered since they were developed, respectively, for a carbonate thermal aquifer in italy (fabbri, 1997) and dolomite aquifers in slovenia (verbovšek, 2008). a similar methodological approach was profitably used to assess the transmissivity of a thermal aquifer in central croatia (pavić et al., 2023). 4. results 4.1. structural analysis of field data the batinjska rijeka quarry (brq) is part of the petrov vrh structural domain (kosović et al., 2024). structurally, it is located at the intersection of the e-w striking gradina fault to the ne and daruvar fault to the sw (fig. 4a). these two reverse faults are laterally displaced by a ne-sw striking fault (fig. 4a) by approximately 570 m. lithologically, the quarry is predominantly composed of a middle triassic dolomite and limestone succession (fig. 2). at the southern face, interlayers of thin layered shale and siltstone/sandstone occur. strata orientation and fracture system measured bedding orientations indicate subvertical bedding within the dolomites and limestone strata (fig. 5a) that are dipping either ne/sw (29 data) or se/nw (39 data) at the dip angle >60° (supplementary tab. 1). the subvertical bedding in the quarry indicate at least two generations of isoclinal folds (fig. 6a) that are characterised by fold axes dipping either towards the se (138°) or the sw (228°) at dip angles of 42° and 16°, respectively (fig. 6a). if the fold generations are considered as second-order structures, they can be interpreted as related to a first-order folded structure that generally dips towards the n at an angle of >65°. the structural analysis encompassed 284 fractures (fig. 6b). three representative fracture systems were delineated (supplementary tab. 2 and fig. 6b). the fs1 fracture system (59 measurements) includes nne-ssw striking subvertical fracture sets that dip to either the ese or the wnw. the fs2 fracture system counts 42 measured data. with a nne-ssw strike similar to fs1, this fracture system dips towards the ese at an angle of 45°. the fracture system fs3 (54 data), composed of two subsets, resembles two coupled subvertical fractures that dip either towards the nne (22°) or the nnw (338°). faults and shear fracture analysis fault analysis focused on addressing the structural architecture and identification of the faults and shear fractures within the area. due to heavily tectonised carbonate quarry faces and the active exploration of the quarry, 50 shear fractures/fault plane data were collected. considering the stress field and kinematic criteria, three principal fault categories were identified and subdivided by fault groups and subsets (fig. 6c and supplementary tab. 3). reverse fault planes (20 data; figs. 6c and 7 and supplementary tab. 3) were separated into two fault sets (rfa and rfb). rfa subset shows an average se dip direction (dip figure 5. (a) tectonised triassic dolomites and dolomitised limestones in the brq at location 45.603°n, 17.272°e. strata are steeply dipping towards the sw (so: 233/70) with a normal fault (198/60) at the base of carbonate beds. (b) coupled fracture systems in the brq at location 45.606°n, 17.273°e. measured fracture systems dip towards the ese (fs2: 100/45), nw (fs3: 338/73), w (fs1b: 288/82). g eologia c roatica 107kosović et al.: hydrogeological parameterisation of the daruvar thermal aquifer: integration of fracture network analysis and well testing figure 6. (a) stereonets of the bedding orientations (small black circles) in the brq. their interpretation highlights the occurrence of generally two generations of folds (fold limbs are shown as small blue and red circles) characterised by different fold hinges (blue and red points). (b) structural diagrams of the main fracture systems (black small circles) in the study area. the orientations of the representative fracture systems (fs) are reported in supplementary tab. 2. they are obtained from the distribution of the measured discontinuities represented here as poles (black points). (c) structural diagrams for the interpreted fault systems (rf reverse fault group; nf normal fault group; ssf-1 and ssf-2 strike-slip fault groups). in all plots, n indicates the number of measurements. g eo lo gi a c ro at ic a 108 geologia croatica 77/2 angle of 56°), whereas the rfb fault subset dips towards the wnw at an angle of 36°. structural analysis and computation of the representative palaeostress field using the p–t axes method and derived synthetic structural focal mechanism show that the palaeostress compressional field was associated with a nw-se trending p-axis (the t-axis is subvertical, steeply dipping towards the nnw), hence nw-se compression. this compressional palaeostress field may have resulted in the formation of the fold generation dipping towards se (138°; fig. 6a) normal fault planes (10 data; supplementary tab. 3 and fig. 6c) showed orientations similar to the reverse faults. they were divided into two fault sets (nfa and nfb) characterised by ne‒sw striking fault planes dipping towards either the se or the nw, at angles of 41° and 50°, respectively. kinematic and stress analysis indicates that observed normal faults were formed due to a subvertical p-axis steeply dipping towards the nne (p-axis orientation is 14/87) and subhorizontal t-axis trending nw‒se. this stress field resulted in the nw–se extension of the existing faulted structures. besides the reverse and normal faults, 19 strike-slip fault planes were measured (supplementary tab. 3; figs. 6c and 7b). measured data were separated based on geometry and kinematic compatibility into two fault systems (ssf-1 and ssf-2) and four group subsets. the ssf-1 group included 10 measured dextral/sinistral faults (dip angle between 53° and 73°) striking either ne–sw or nw–se. the ssf-2 group incorporated conjugate fault pairs with nne–ssw and se-nw strike (dip angle between 66° and 71°). mapped strikeslip fault planes often showed structural reactivation with both dextral/sinistral motions. similar orientations of two nw-se striking fault subsets (ssf-1b and ssf-2b) indicate fault structural reactivation and reorientation of the principal stress axes σ1 and σ3 within a relatively short timeframe. both strike-slip fault groups were formed in two slightly different palaeostress fields. the ssf-1 fault group indicates a palaeostress field associated with the nne–ssw trending p-axis, whereas ssf-2 fault group indicates a palaeostress field associated with an ene-wsw trending p-axis. this implies that both strike-slip fault groups were tectonically active within a general ne-sw transpressional stress field. 4.2. digital structural analysis of the dom the discontinuities digitalised in the selected sections of the dom are shown in fig. 8. the contour plots of the poles were used to identify the main sets of discontinuities in each section (supplementary tab. 4). quarry section 2 (length: 145 m, height: 17 m, representa tive dip direction and dip: 282/68) is located on the lowest level of the quarry. the dom analysis reveals that three discontinuity systems crosscut the rock mass. the discontinuity system d1 is composed of two ne-sw striking subvertical discontinuities dipping at high angles (76° and 83°, respectively) toward the nw (d1a; 20 data) or ese (d1b; 17 data). the d2 system is divided into d2a and d2b sets (23 and 15 data, respectively) and includes predominantly nnw-sse striking discontinuities dipping towards the wsw or w with dip angles of 53° and 57°, respectively. the d3 system (21 data) is characterised by discontinuities that are steeply dipping at high angles (≥87°) towards the w. quarry face 3 is divided into sections a (length: 97 m, height: 30 m, representative dip direction and dip: 259/70) and b (length: 63 m, height: 31 m, representative dip direction and dip: 297/68). analysis of the dom in section 3a shows two discontinuity systems d1 and d2. the d1 system is characterised by two discontinuity sets (d1a and d1b; 132 and 43 measurements, respectively) dipping towards the wnw with dip angles of 68° and 83°. the d2 system comprises two sets dipping towards the wsw but at different dip angles. d2a (140 data) is steeply dipping towards the wsw at 75°, while set d2b (74 data) is gently dipping with a dip angle of 41°. the structural fabric of section 3b is similar to section 3a being deformed by two discontinuity systems (d1 and d2). the d1 system is characterised by ne-sw striking discontinuity sets. figure 7. (a) fault plane (167/45) observable across most of the brq faces, at location 45.606°n; 17.273°e. fault plane shows reverse kinematics with indication of tectonic transport to the nw, while in the same time this fault plane experienced structural reactivation and tectonic inversion characterised by nw-se oriented extension. (b) reverse fault planes with average orientation 142/30 (fp). besides nw tectonic transport, we observed subvertical bedding with average strata orientation 318/75. in the right section, a subvertical bedding plane (fp2) was structurally reactivated as a dextral fault. g eologia c roatica 109kosović et al.: hydrogeological parameterisation of the daruvar thermal aquifer: integration of fracture network analysis and well testing set d1a (124 data) dips towards the nnw (dip angle of 70°), whereas the d1b set (73 data) includes discontinuities that steeply dip towards the nw at a dip angle of 77°. the second discontinuity system (d2; 115 data) encompasses the nnwsse striking discontinuities that dip steeply towards the wsw at an angle of 72°. quarry face 4 (length: 108 m, height: 30 m, representative dip direction and dip: 290/66) is similar to quarry face 3 being deformed by two discontinuity systems d1 and d2. the d1 system is characterised by two sets (d1a and d1b; 103 and 86 data, respectively) steeply dipping towards the nnw or nw. the d2 system (89 measurements) includes predominantly nnw-sse striking discontinuities steeply dipping towards the wsw (dip angle of 72°). quarry section 5 (length: 78 m, height: 18 m, representative dip direction and dip: 286/69) is deformed by two discontinuity systems (d1 and d2) that dip towards either the nw or w at angles of 71° and 72°, respectively. two discontinuity systems d1 and d2 were delineated in the highest face of the quarry (section 6; length: 53 m, height: 11 m, representative dip direction and dip: 298/65). the d1 system includes the d1a and d1b sets (16 and 9 data, respectively), characterised by discontinuities steeply dipping towards the nnw with a dip angle of approximately 70°. the d2 system encompasses ne-sw striking discontinuities that are steeply dipping towards the w at an angle of 60° (d2a set; 5 measurements) and 81° (d2b; 8 data), respectively. based on the structural analysis of the dom, two subvertical systems (d1 and d2) of discontinuities can be distinguished. the d1 system generally dips toward the nw, while the d2 system shows a general nnw-sse strike dipping towards the wsw. the section of the quarry qs3a (fig. 4b) was selected for a detailed analysis of the discontinuity sets to derive the input parameters for the discrete fracture network (dfn) modelling. the high-resolution orthophotograph of the section was digitised in qgis obtaining a shapefile of discontinuity traces, i.e. the intersections of the discontinuity planes with the quarry face (fig. 9). since the face dips 70° towards w, it intersects all the discontinuity systems identified in this sector of the quarry (fig. 8). sets d1a and d1b (subvertical in the orthophoto; red set in fig. 9) differ by just 20° in strike and it was impossible to separate them based on their traces on the orthophotograph. they were merged into one set (named set v). the traces of systems d2a and d2b (at medium and low angle in the orthophoto; green set in fig. 9) show a continuous range of plunges, without a clear cutoff angle between them. the medium to low angle traces were therefore considered as a merged system (named set h). the parameters calculated for the two merged sets visible in section qs3a are listed in supplementary tab. 5. the merged sets show a dispersed distribution of their spatial orientation, as evidenced by the relatively low values of the fisher k (13.53 for set h and 18.83 for set v). since section qs3a is subvertical, the length of the traces corresponds to fracture heights. the percentage of censored heights is 20% and 11.08% in sets v and h, respectively (supplementary tab. 5). a log-normal distribution best fits the distribution of the measured heights, accounting for censoring bias (supplementary fig. 1). the figure 8. structural diagrams of the main discontinuity systems in the different sections of the quarry (n: number of data). the orientations of the representative discontinuity systems are reported in supplementary tab. 4. they are obtained from the distribution of the measured discontinuities in the dom of brq here represented as poles (black hollow points). g eo lo gi a c ro at ic a 110 geologia croatica 77/2 cumulative fracture lengths were used to calculate the areal fracture intensity p21 being 0.47 and 0.37 for set h and v, respectively. 4.3. dfn modelling of the aquifer outcrop analogue the results obtained from the dom and qs3a virtual structural analyses were used to build the dfn model of the outcrop. the model size was 100×100×30 m (xyz; fig. 10a) corresponding to the length and height of the qs3a section. the input parameters used for the construction of dfn models in both the software dfnworks and move are reported in supplementary tab. 6 including the p32 and aperture values obtained after the calibration procedure. the calibration of p32 was based on the iterative building of dfns in the dfnworks software, pointing to a ratio c1 (eq. 1) of 0.24 and 0.21 for set h and set v, respectively. these linear coefficients were used to calculate the p32 from the p21 obtained through the digitalisation of the fracture traces in the qs3a section resulting in p32 values of 1.98 and 1.18 m2/m3 for set h and set v, respectively. the aperture was calibrated to fit the porosity (φ) distribution in the dfn model with the φ field measured during well logging of dar 1 well. the analysis of the well log showed a large variation in the φ ranging from 0.03 to 42% (average = 7.9%). the occurrence of outliers was indicated by the fact that the 10th and 90th percentiles of the distribution are 0.9 and 17%, respectively, suggesting a narrower φ field. a closer inspection of the caliper well log showed a variation in the diameter of the borehole from 35 to 45 cm (nominal diameter of the drill bit was 31.1 cm), with the high φ occurring in the well sections with larger diameters. these data suggest that the wall of the well locally collapsed (most probably in the more fractured part of the reservoir), affecting the measurement of the φ. the section of the well with both a smaller and more homogeneous diameter was selected to obtain a more realistic assessment of the φ. these conditions should point to a more compact wall of the well, resulting in φ values that should better reflect the φ field in the aquifer. the selected section was located at a depth of 100-130 m showing a homogenous diameter between 35 and 36 cm. the φ within this interval is between 0.03 and 9.1% with an average value of 2.7%. the 10th and 90th percentiles of the distribution are 0.2 and 6.3%, respectively, suggesting a more homogeneous distribution around the average than the whole φ dataset. the φ calibration was conducted testing values of the fracture aperture from 0.1 to 10 mm and combining them with the different approaches for assigning the aperture in the move software. the modelling domain was discretised using a grid spacing of 0.5 m considering that the φ in the dar 1 well was calculated from the neutron log generally having a vertical resolution of 1 m and depth of investigation of 25 cm (lai et al., 2024). the distributions of φ and k obtained for the tested aperture values and employing the different methodological approaches are shown in supplementary figs. 2 and 3, respectively, while their statistical analyses are in supplementary tabs. 7 and 8. a general increase of both the φ and k fields with the aperture was observed except for the minimum and 10th percentile of the distributions, which were always 0. this value is the outcome of choosing a small grid size since the software assigns null φ/k to those cells that are not cut by any structure. considering the same aperture, the highest values were obtained with the method “aperture proportional to length”, while the method “constant aperture” showed the lowest values. this discrepancy can be explained by the different methodological approaches for calculating the aperture. in the “aperture proportional to length” approach, long fractures have larger apertures than short fractures resulting in both higher φ and k values. in the “constant aperture” approach, the same aperture is applied to all fractures diminishing the effect of long and potentially wider fractures on the hydraulic parameters. this effect is also visible by analysing the skewness and kurtosis values of the distributions. skewness and kurtosis are higher than 0.9 and 3.8, respectively, suggesting right-skewed and leptokurtic distributions. these data suggest a clustering of the datasets toward low values with a long right tail toward high values. the highest skewness and kurtosis were observed in the “aperture proportional to length” approach enforcing the figure 9. orthophotograph of section qs3a digitised in qgis to vectorise the traces of the discontinuity systems. traces are divided into two discontinuity systems: subvertical (red; set v in supplementary tab. 5) and subhorizontal (green; set h in supplementary tab. 5). g eologia c roatica 111kosović et al.: hydrogeological parameterisation of the daruvar thermal aquifer: integration of fracture network analysis and well testing occurrence of high φ/k values associated with wider fractures. it should be noted that a similar asymmetric distribution was depicted in the experimental φ of the dar 1 well. the statistical analysis of the φ in the dfn models was further detailed to calibrate the aperture. a linear relationship (fig. 10b) between the aperture and all statistical indexes is observed, except for the minimum and 10th percentile values. the slopes of the average values for the different methodological approaches were calculated to obtain the aperture fitting with the average φ measured in dar 1 well at a depth of 100–130 m. the resulting apertures were 8.9, 5.1, and 4.1 mm for the constant, root length, and length approaches, respectively. the aperture values obtained with the second and third approaches seem more realistic and applicable for a fractured aquifer, while wider apertures could be more representative of karst aquifers. the model was run with an aperture of 4.1 mm and employing the “aperture proportional to the fracture length” approach. the resulting φ ranged from 0 to 22.7%, but the statistical analysis showed that the φ distribution (red dots in fig. 10c) fits the experimental values at the depth of 100–130 m (red lines in fig. 10c) with only a minor discrepancy observed for the 75th percentile. the resulting k value ranged from 0 to 4.4×106 d and an average value of 2.7×105 d. the statistical distributions of both φ and k are right-skewed and leptokurtic (skewness of 1.1 and 2.4, respectively, and kurtosis of 4.3 and 11.2, respectively) indicating a highly asymmetric distributions. figure 10. (a) dfn model obtained using the input parameters in supplementary tab. 5. the red and green discontinuities represent the vertical and horizontal discontinuity sets, respectively. (b) mean (black lines) and maximum (red lines) porosity values obtained using different approaches for assigning the aperture to fractures in the dfn model (dotted lines: constant aperture; dashed lines: aperture proportional to the root of the length; full lines: aperture proportional to the length). (c) porosity distribution (black lines) obtained using the “aperture proportional to length” approach. it was considered the best approach for fitting the experimental porosity distribution (dashed red lines) of the dar 1 well at a depth of 100-130 m. the results obtained from the best model with aperture of 4.1 mm are shown as red dots suggesting a good fit with the experimental data. g eo lo gi a c ro at ic a 112 geologia croatica 77/2 4.4. interpretation of pumping and well tests the pumping test in the daruvar thermal field lasted approximately 12 h. it was conducted performing 3 steps (i.e., stepdrawdown test) with flow rates of 12.1, 13.4, and 7.2 l/s, respectively, lasting 1 h each (fig. 11a). the pumping was stopped for 1 h measuring the recovery of the water level. afterwards, a flow rate of 12.3 l/s was set for approximately 7 h (i.e., constant test). the subsequent recovery of the water level was measured for 1.5 h reaching the initial water level. a maximum drawdown (δ) of 0.59 m was observed in the dar 1 well at the end of the second pumping step, while the highest δ in the observation wells d 1 and ds 1 was measured during the constant test reaching 0.09 m (fig. 11a). the water level in the antunovo vrelo spring was slightly affected by the pumping showing a δ up to 0.01 m. the δ values measured in dar 1, d1, and ds 1 were used for determining the hydrogeological parameters of the aquifer using both the theis-hantush analytical solution for pumping tests. the solution was calculated using the data from the whole pumping test (i.e., step-drawdown and constant tests; fig. 11b) and only from the constant test (fig. 11c). the obtained parameters are summarised in supplementary tab. 9. the results of the two methodological approaches are com parable. the transmissivity (t) is 3.82×10–2 m2/s and 3.46×10–2 m2/s, while the saturated thickness of the aquifer (b) is 61.5 and 68.4 m for the whole and constant tests, respectively. the saturated thickness value slightly corresponds to the length of the screened section of the dar 1 well (53 m, and up to 59 m if a short part of casing between the two well screens is included). furthermore, the data measured in dar 1 were used to assess the drawdown vs. flow rate curve of the well, the well efficiency (w), and the specific capacity (sc). the obtained results are summarised in supplementary fig. 4. the calculated drawdown vs. flow rate curve is: 21 4.6 2186.6 q q∆ = + (4) w is between 33% and 48% and decreases by increasing the flow rate. although w is low showing a poor efficiency, it is acceptable considering that the dar 1 well is relatively old and it has practically never been used. the sc was calculated considering both the experimental and theoretical δ showing minor differences. the resulting t values are 3.8×10–2 m2/s and 4.8×10–2 m2/s for the equations 2 and 3, respectively. considering that these values are obtained using experimental relationships developed in geological and hydrogeological settings different from the daruvar thermal field, the slight discrepancy with the t calculated from the pumping test approach is acceptable. 5. discussion 5.1. integrated interpretation of field and virtual structural data fractures are the main f low path in fractured aquifers (faulkner et al., 2010; bense et al., 2013). reconstructing the geometric characteristics of the fracture network and the stress field deforming the rock mass can be useful in determining the preferential flow paths fostering the conceptual figure 11. (a) drawdown measured in the wells dar 1, d 1, and ds 1 and the antunovo vrelo spring during the pumping test conducted in 2022. the flow rate is shown as a step plot with a dashed line. (b-c) drawdown data for dar 1 (black circle), d 1 (red cross), and ds 1 (blue square) fitted with the theoretical theis curves (black, red, and blue lines for dar 1, d 1, and ds 1, respectively) for the whole pumping test (b) and the constant flow rate test (c). g eologia c roatica 113kosović et al.: hydrogeological parameterisation of the daruvar thermal aquifer: integration of fracture network analysis and well testing model of the groundwater resource (singhal & gupta, 2010). integrated structural mapping based on field measurements and digital outcrop model (dom) analysis was employed in this work to analyse the fracture network in the batinjska rijeka quarry (brq). the results of the field measurements indicate that the mesozoic carbonate complex in the quarry is deformed by systems of folds and fractures being a representative outcrop analogue for the fractured carbonate reservoir of the daruvar hydrothermal system. folded structures in the brq are characterised by subvertical bedding (dipping either ne/sw or se/nw; fig. 6a) that have undergone extensive brittle deformation with the formation of three systems of fractures (fs1 and fs3 including fractures steeply dipping toward ese or nne, and fs2 including low angle fractures dipping toward the ese; fig. 6b). the geometry, structural position, and subvertical orientation of these systems indicate a cogenetic relationship with the fold hinge zones that have an predominantly ne-sw and esewnw strike. structural observations of shear fractures/fault planes (fig. 6c) corroborate the results of the bedding and fracture system analyses, suggesting that the present-day fracture pattern observed in the brq results from the multiphase regional tectonics (kosović et al., 2024). cretaceous-palaeogene e-w (or ne-sw) compression rotated by 40º counterclockwise is observed on nne-striking reverse fault planes associated with a nw-se oriented p-axis (supplementary tab. 3 and fig. 6c). ne-striking normal faults indicate a nw-se oriented extension and clockwise rotation of the existing nne-striking reverse fault due to a tectonic inversion. the observed extension may be related to the collapse of the hanging wall structures of the cretaceouspalaeogene reverse faults due to either gravitational slip (e.g. tavani et al., 2012) or the initial extension of the pbs in the late oligocene and miocene (tomljenović & csontos, 2001). the n-s (ne-sw) compressional/transpressional phase from the pliocene-quaternary is observed on strike-slip fault planes (supplementary tab. 3), showing polyphase structural reactivation and repeated movements in both a dextral and sinistral sense. considering the cross-cutting relationships between ssf-1 and ssf-2 fault systems and mapped reverse/normal faults, it indicates that the strike-slip fault planes are younger and probably associated with the most recent pliocene-quaternary tectonic phase in the study area (e.g., tomljenović & csontos, 2001; schmid et al., 2008). this ne-sw oriented stress field may also influence the bedding reorientation and the formation of a younger fold system that gently dips towards the se (fig. 6a). results of the dom virtual structural analysis depicted two dominant subvertical systems (d1 and d2; supplementary tab. 4) of discontinuities. the d1 system generally dips toward the nw, while the d2 system dips towards the wsw. these results correspond well with the field observations (supplementary tabs. 1 and 2). the d1 system has the same orientation as the bedding so3 and the fracture set fs3b. discontinuity system d2 has a similar orientation to the bedding so2 and fracture set fs1b. other sets of bedding and fractures observed by field measurements don’t clearly correspond with the discontinuity systems delineated in the dom. only the fracture set fs1a (supplementary tabs. 1 and 2) could have an analogy with the discontinuity set d1b measured in quarry section 2 (supplementary tab. 4). however, this discontinuity set is depicted only in one section of the quarry and is obtained from a limited dataset, decreasing the reliability of its geometric characterisation in the dom. the lack of correlation between field data and the dom results could be associated with several factors. fracture sampling in the dom highly depends on the outcrop inclination and the fracture 3d spatial orientation (priest, 1993; zhang & einstein, 1998; zeeb et al., 2013). this difference significantly reduces the identification of potential fracture systems that are either parallel or steeply dipping in opposite directions to the quarry face during the dom analysis. furthermore, field investigations and virtual outcrop analysis have different resolution scales (tziavou et al., 2018; martinelli et al., 2020): discontinuities at the centimetre scale can be measured in the field, while they are impossible to digitalise in decametre scale doms. bearing in mind the different resolutions of the methods, only metre scale discontinuities were measured during the field investigations in the brq. still, a discrepancy between the results occurred highlighting the intrinsic difference between the two methodological approaches. however, the digital outcrop analysis of the brq covered a relatively large area favouring: i) reconstruction of the discontinuity network in remote or inaccessible portions of the outcrop, and ii) collection of a large dataset that was used for a detailed statistical analysis of the geometric features of the main discontinuity sets. 5.2. hydrogeological parameterisation of the daruvar thermal aquifer besides their primary role in the circulation of groundwater, networks of fractures can influence the distribution of the bulk permeability (k) and porosity (φ) in fractured aquifers (e.g., faybishenko et al., 2000; singhal & gupta, 2010; bense et al., 2013). in this study, both classical hydrogeological investigations and discrete fracture network (dfn) modelling were conducted for the hydraulic parameterisation of the daruvar carbonate thermal reservoir. several pumping and well tests have been conducted in the daruvar thermal field to assess the transmissivity (t) of the aquifer (borović, 2015; borović et al., 2019; urumović et al., 2023). in particular, borović (2015) critically revised and reanalysed the results from old pumping tests (1971, 1980, 1982, 2009), providing a solid estimation of t. here, the results of a recent pumping test (2022) were analysed using several methodological approaches (theis, 1935; hantush, 1961a, b; kruseman et al., 2000). the t values obtained in this work and from the literature range from 1.58×10-2 to 4.83×10-2 m2/s showing a good concordance among the different methods (tab. 1). the average t was used to calculate the aquifer k value considering: i) the lower density and viscosity of the thermal waters due to their temperature and salinity, and ii) both the thicknesses of the dolomite aquifer and the fracture corridors in the dar 1 well (d and f, respectively; tab. 1) and the saturated thicknesses calculated from the pumping test analysis (b; tab. 1). the resulting average values of k (tab. 1) are 16.4, 32.7, and 88.7 d considering d, b, and f as the aquifer thickness, respectively. g eo lo gi a c ro at ic a 114 geologia croatica 77/2 these values show good consistency within the same order of magnitude and are within the range of k values for fractured and karst carbonate aquifers (freeze & cherry, 1979). the φ of the aquifer was obtained through well logging of the dar 1 well. since the distribution of φ values showed a large variability (tab. 1), a section of the well with tight walls (depth of 100–130 m) was considered to obtain a narrower, more realistic, range of φ. the average φ for this section was 2.7% (tab. 1) being within the range of φ in carbonates (ng & santamarina, 2023). the distribution of φ at a depth of 100–130 m was used for the calibration of the dfn model of the brq outcrop analogue. the best fit of the model was obtained using an aperture of 4.1 mm resulting in an average φ of 2.7% and an average k of 2.7×105 d. although the φ fits with the experimental values, the k value is 3-4 orders of magnitude higher than the measured k (tab. 1). the reasons for this discrepancy could be that: i) the φ used for the calibration corresponds to the total φ, while effective φ is relevant for the fluid flow, and ii) the size and the discretisation of the dfn model do not correspond to the area investigated by the pumping test and the hydrogeological representative elementary volume. in order to overcome these issues, a larger dfn model was conducted. the model size was increased to 700×700×150 m (xyz; fig. 12a) being more representative of the aquifer volume investigated by the pumping test. it was considered that the radius of influence of the pumping test was between the ds 1 and d 1 observation points and the antunovo vrelo spring, because the experimental data showed variations of the water level in the observation wells (figs. 3 and 11a). therefore, the horizontal size of the model was calculated to be representative of twice the average distance between the exploitation well dar 1 and the observation points (dar 1 d 1: 265 m, dar 1 – antunovo vrelo: 450 m; fig. 3). the vertical size was chosen to be representative of the maximum investigated thickness of the dolomite in the daruvar area (d in tab. 1). the model was conducted using the software move and it was discretised using: i) a geocellular volume with a cell size as the dfn model of the outcrop analogue for generating the fracture network, and ii) a single cell (i.e., the whole volume) for the hydraulic parameterisation. this “double-sized” geocellular volume permits: i) construction of the fractures using the input parameters of the outcrop dfn model (supplementary tab. 6), and ii) calculation of the hydraulic parameters over a volume that is representative of the investigated section of the aquifer. through this approach, the fracture geometry at the aquifer scale dfn is constrained using the geometric parameters obtained from the dom virtual structural analysis, and the bulk hydraulic parameters are calculated obtaining an estimation at the scale of the pumping test. the model was run using the “aperture proportional to the fracture length” approach since it seemed more reliable for fractured aquifers. different aperture values were tested obtaining a linear and power correlation with φ and k (figs. 12b-c). the aperture of 4.1 mm (i.e., the best fit in the outcrop analogue dfn model) results in a φ and k of 3.7% and 3.9×105 d, respectively. these values are slightly higher than the results of the outcrop scale dfn model, probably due to the different geocellular volume used for the calculations. the linear relationship between the aperture and φ was used to recalibrate the aperture value fitting the average φ at the depth of 100–130 m (tab. 1). the resulting aperture of 3 mm was run in the model obtaining a k value of 1.5×105 d, which is 3–4 orders of magnitude higher than the experimental values. this result suggests once more that two different aperture values are needed for fitting the experimental φ and k values. in particular, the hydraulic aperture of the fractures, which is smaller than the mechanical aperture (renshaw, 1995; pouraskarparast et al., 2024), should be used for reconstructing the k value in dfn models (e.g., smeraglia et al., 2021). furthermore, the effective φ should be considered since fractured aquifers usually have dual porosity, with most of the storage volume being in the matrix and most of the flow being in the fracture network (worthington et al., 2019). the φ dataset used for the calibration of the dfn models was calculated from the neutron log and describes the total φ of the daruvar aquifer. considering that effective φ in carbonate rocks is at least one order of magnitude less than total φ (worthington et al., 2019), the fracture aperture for obtaining a φ of 0.27% (i.e., one order of magnitude lower than the average φ at the depth of 100-130 m; tab. 1) was calculated and input to the model. the calculated fracture aperture was 0.3 mm resulting in a k value of 149.4 d, which is slightly higher than the experimental values. the effective φ value was refined on the basis of the experimental φ dataset, and the 10th percentile of the φ distribution was tested (tab. 1). the corresponding fracture aperture (0.22 mm) was input to the model resulting in φ and k values of 0.2% and 60.5 d, respectively. the k value fits with the experimental values being in the range of the k calculated from f and slightly higher than the values obtained from d and b (tab. 1). the results of the conducted numerical investigations highlight the importance of employing a “dual aperture” approach for fitting both experimental φ and k values in dfn models. this approach is necessary since fractured aquifers are a dual continuum medium where the groundwater is table 1. hydrogeological parameterisation of the daruvar thermal aquifer obtained from: i) the interpretation of pumping and well tests in this study, ii) the well logging of dar 1 well, and iii) the literature (borović et al., 2019; urumović et al., 2023). average value minimum – maximum 10th – 90th percentile investigated thickness of dolomite d (m) 130 – – saturated thickness b (m) 65 61.5 – 68.4 – thickness of fracture corridors f (m) 24 transmissivity t (m2/s) 3.5e-2 1.6e-2 – 4.8e-2 2.5e-2 – 4.3e-2 storativity s (–) 1.6e-3 1.1e-3 – 2e-3 – hydraulic conductivity anisotropy ratio kz/kr (–) 1.3e-2 6.8e-3 – 2e-2 – permeability from d k d (d) 16.4 7.4 – 22.7 11.8 – 20.3 permeability from b k b (d) 32.7 14.8 – 45.3 23.6 – 40.6 permeability from f k f (d) 88.7 40 – 122.8 63.8 – 109.9 porosity φ (%) 7.9 0.03 – 42 0.9 – 17.4 porosity at depth 100-130 m φ* (%) 2.7 0.03 – 9.1 0.2 – 6.3 g eologia c roatica 115kosović et al.: hydrogeological parameterisation of the daruvar thermal aquifer: integration of fracture network analysis and well testing mostly stored in the rock matrix, affecting the total porosity of the aquifer, while the fluid flow occurs in the fractures, being influenced by their hydraulic aperture and the effective porosity of the aquifer. this difference should also be considered for the analytical interpretation of pumping tests. here, a generally well accepted analytical method reproducing the aquifer as an equivalent porous medium was used (singhal & gupta, 2010), but it provides only a rough estimation of the k value. the estimation of k in dual porosity media requires more sophisticated field investigations (i.e., flowmeter and quantitative visual logging, tracer tests) and analytical methods for modelling the pumping test results (i.e., moench, 1984). 6. conclusions this paper describes the results of an integrated approach for reconstructing the network of fractures and quantifying the hydraulic parameters in fractured aquifers. structural and hydrogeological investigations were conducted in the daruvar thermal area and its hinterland detailing the structural architecture and the hydraulic parameterisation of the carbonate thermal aquifer. the results obtained through field and virtual structural analyses were used as input parameters to construct discrete fracture network models at different scales to estimate the aquifer properties. the modelling results were compared with the results of hydrogeological field investigations obtaining a good correlation. these results permit the quantification of the impact of the fracture network on the permeability field of the daruvar thermal aquifer as observed in fractured aquifers. the results obtained in the investigation of the daruvar thermal area demonstrate that an integrated approach is invaluable in investigating and modelling fractured media. the utilisation of such an integrated approach permits a figure 12. (a) aquifer scale dfn model obtained using the input parameters in supplementary tab. 5. the red and green discontinuities (1% of the generated discontinuities is shown) represent the vertical and horizontal discontinuity set, respectively. (b-c) porosity and permeability values (black dots) obtained from the aquifer scale dfn using different fracture apertures. the results of the best model (aperture of 0.22 mm) are shown as red dots pointing to a good fit with the experimental data (dashed lines). g eo lo gi a c ro at ic a 116 geologia croatica 77/2 quantitative structural and hydrogeological reconstruction of the aquifer and the network of fractures favouring the fluid flow accounting for the advantages of both techniques. field analysis can be used to determine the geological relationship among structures and the stress field developing the dis continuities. remote sensing photogrammetry allows the construction of a 3d digital model of the outcrop favouring the collection of large datasets for a detailed quantitative description and statistical analysis of geological objects' geometry and their spatial relationships (hodgetts, 2013; bistacchi et al., 2015; martinelli et al., 2020). field research can add a conceptual link to the results of the data analysis in the dom obtaining a more comprehensive geological interpretation. furthermore, the obtained results highlight the importance of correlating the results from structural and hydrogeological investigations. structural data can be used to construct discrete fracture network models of the fractured aquifer that need to be calibrated using the data from hydrogeological investigations. depending on the available experimental dataset of hydrogeological properties, the model calibration needs to account for the dual porosity of fractured aquifers and the difference between the mechanical and hydraulic aperture of the fractures. acknowledgment the authors would like to thank the editorial team for the support during the preparation and the revision of the manuscript, the two anonymous reviewers for their useful comments, the daruvarske toplice–special hospital for medical rehabilitation and pivovara daruvar d.o.o. for logistic help on-site and sharing of existing materials and matej manjarić and inter-promet d.o.o. for allowing the access to the batinjska rijeka quarry and the logistic support during the investigations. this research was funded by the hythec project of the croatian science foundation (hrzz), grant number uip-2019-04-1218. references allmendinger, r.w., cardozo, n. & fisher, d.m. (2011): structural geology algorithms: vectors and tensors.– cambridge university press, 289 p. doi: 10.1017/cbo9780511920202 angelier, j. & mechler, p. (1977): sur une methode graphique de recherche des contraintes principales egalement utilisables en tectonique et en seismologie: la methode des diedres droits.– bulletin de la société géologique de france, s7-xix(6), 1309–1318. doi: 10.2113/gssgfbull.s7xix.6.1309 antonellini, m., cilona, a., tondi, e., zambrano, m. & agosta, f. (2014): fluid flow numerical experiments of faulted porous carbonates, northwest sicily (italy).– marine and petroleum geology, 55, 186–201. doi: 10.1016/j.marpetgeo.2013.12.003. bada, g., horváth, f., dövényi, p., szafián, p., windhoffer, g. & cloetingh, s. (2007): present-day stress field and tectonic inversion in the pannonian basin.– global and planetary change, 58/1–4, 165–180. doi: 10.1016/j.gloplacha.2007.01.007 balen, d., horváth, p., tomljenović, b., finger, f., humer, b., pamić, j. & árkai, p. (2006): a record of pre-variscan barrovian regional metamorphism in the eastern part of the slavonian mountains (ne croatia).– mineralogy and petrology, 87/1–2, 143–162. doi: 10.1007/ s00710-006-0120-1 bense, v. f., gleeson, t., loveless, s. e., bour, o. & scibek, j. (2013): fault zone hydrogeology.– earth-science reviews, 127, 171–192. doi: 10.1016/j.earscirev.2013.09.008 benedetti, g., casiraghi, s., bistacchi, a., & bertacchi, d. (2024): fracability: a python toolbox for survival analysis in fractured rock systems.– in: egu general assembly, vienna, austria, 14–19 apr 2024. egu24-22156. doi: 10.5194/egusphere-egu24-22156, 2024. bistacchi, a., balsamo, f., storti, f., mozafari, m., swennen, r., solum, j., tueckmantel, c. & taberner, c. (2015): photogrammetric digital outcrop reconstruction, visualization with textured surfaces, and three-dimensional structural analysis and modeling: innovative methodologies applied to fault-related dolomitization (vajont limestone, southern alps, italy).– geosphere, 11/6, 2031–2048. doi: 10.1130/ges01005.1 bistacchi, a., mittempergher, s., martinelli, m. & storti, f. (2020): on a new robust workflow for the statistical and spatial analysis of fracture data collected with scanlines (or the importance of stationarity).– solid earth. doi: 10.5194/se-2020-83 borović, s. (2015): integrirani hidrogeološko hidrogeokemijski model daruvarskog geotermalnog vodonosnika [integrated hydrogeological hydrogeochemical model of daruvar geothermal aquifer – in croatian].– unpubl. phd thesis, faculty of mining, geology and petroleum engineering, university of zagreb, 228 p. borović, s. & marković, i. (2015): utilization and tourism valorisation of geothermal waters in croatia.– renewable and sustainable energy reviews, 44, 52–63. doi: 10.1016/j.rser.2014.12.022 borović, s., pola, m., bačani, a. & urumović, k. (2019): constraining the recharge area of a hydrothermal system in fractured carbonates by numerical modelling.– geothermics, 82, 128–149. doi: 10.1016/j.geothermics.2019.05.017 caine, j. s., evans, j. p. & forster, c. b. (1996): fault zone architecture and permeability structure.– geology, 24/11, 1025–1028. doi: 10.1130/0091-7613(1996)024<1025:fzaaps>2.3.co cardozo, n. & allmendinger, r. w. (2013): spherical projections with osxstereonet.– computers and geosciences, 51, 193–205. doi: 10.1016/j.cageo.2012.07.021. carrera, j. & martinez-landa, l. (2000): mixed discrete-continuum models: a summary of experiences in test interpretation and model prediction.– in: faybishenko, b., witherspoon, p.a. & benson, s.m. (eds.): dynamics of fluid in fractured rock, 251–265. doi: 10.1029/gm122p0251 csontos, l. & vörös, a. (2004): mesozoic plate tectonic reconstruction of the carpathian region.– palaeogeography, palaeoclimatology, palaeoecology, 210/1, 1–56. doi: 10.1016/j.palaeo.2004.02.033 ceccato, a., viola, g., antonellini, m., tartaglia, g. & ryan, e.j. (2021): constraints upon fault zone properties by combined structural analysis of virtual outcrop models and discrete fracture network modelling.– journal of structural geology, 152, 104444. doi: 10.1016/j.jsg.2021.104444 delvaux, d. & sperner, b. (2003): new aspects of tectonic stress inversion with reference to the tensor program.– geological society, london, special publications, 212/1, 75–100. doi: 10.1144/gsl. sp.2003.212.01.06 dershowitz, w.s. & herda, h.h. (1992): interpretation of fracture spacing and intensity.– all days, arma-92-0757. doblas, m. (1998): slickenside kinematic indicators.– tectonophysics, 295/1–2, 187–197. doi: 10.1016/s0040-1951(98)00120-6 de dreuzy, j.‐r., davy, p. & bour, o. (2002): hydraulic properties of two‐dimensional random fracture networks following power law distributions of length and aperture.– water resources research, 38/12, 1276. doi: 10.1029/2001wr001009 de dreuzy, j., davy, p. & bour, o. (2001): hydraulic properties of two‐ dimensional random fracture networks following a power law length distribution: 2. permeability of networks based on lognormal distribution of apertures.– water resources research, 37/8, 2079–2095. doi: 10.1029/2001wr900010 g eologia c roatica 117kosović et al.: hydrogeological parameterisation of the daruvar thermal aquifer: integration of fracture network analysis and well testing duffield, g.m. (2007): aqtesolv for windows version 4.5 user's guide.– hydrosolve, inc., reston, va. fabbri, p. (1997): transmissivity in the geothermal euganean basin: a geostatistical analysis.– ground water, 355, 881–887. doi: 10.1111/j.1745-6584.1997.tb00156.x faulkner, d.r., jackson, c.a.l., lunn, r.j., schlische, r.w., shipton, z.k., wibberley, c.a.j. & withjack, m.o. (2010): a review of recent developments concerning the structure, mechanics and fluid flow properties of fault zones.– journal of structural geology, 32/11, 1557–1575. doi: 10.1016/j.jsg.2010.06.009 faybishenko, b., witherspoon, p.a. & benson, s.m. (2000): dynamics of fluids in fractured rock. geophysical monograph series. vol. 122. – american geophysical union, washington, d. c. doi:10.1029/ gm122 freeze, r.a. & cherry, j.a. (1979): groundwater.– englewood cliffs, nj: prentice-hall, 604 p. finster, m., clark, c., schroeder, j. & martino, l. (2015): geothermal produced fluids: characteristics, treatment technologies, and management options.– renewable and sustainable energy reviews, 50, 952–966. doi: 10.1016/j.rser.2015.05.059 giuffrida, a., la bruna, v., castelluccio, p., panza, e., rustichelli, a., tondi, e., giorgioni, m. & agosta, f. (2019): fracture simulation parameters of fractured reservoirs: analogy with outcropping carbonates of the inner apulian platform, southern italy.– journal of structural geology, 123, 18–41. doi: 10.1016/j.jsg.2019.02.007 guihéneuf, n., dausse, a., de dreuzy, j.r. & parker, b.l. (2021): flow-bearing structures of fractured rocks: insights from hydraulic property scalings revealed by a pumping test.– journal of hydrology, 598. doi: 10.1016/j.jhydrol.2020.125715 hantush, m.s. (1961a): aquifer tests on partially penetrating wells.– journal of the hydraulics division, 87/5, 171–195. doi: 10.1061/ jyceaj.0000639 hantush, m. s. (1961b): drawdown around a partially penetrating well.– journal of the hydraulics division, 87/4, 83–98. doi: 10.1061/jyceaj.0000633 hodgetts, d. (2013): laser scanning and digital outcrop geology in the petroleum industry: a review.– marine and petroleum geology, 46, 335–354. doi: 10.1016/j.marpetgeo.2013.02.014 horváth, f., musitz, b., balázs, a., végh, a., uhrin, a., nádor, a., koroknai, b., pap, n., tóth, t. & wórum, g. (2015): evolution of the pannonian basin and its geothermal resources.– geothermics, 53, 328–352. doi: 10.1016/j.geothermics.2014.07.009 horváth, f., bada, g., szafián, p., tari, g., ádám, a. & cloetingh, s. (2006): formation and deformation of the pannonian basin: constraints from observational data.– geological society memoir, 32, 191–206. doi: 10.1144/gsl.mem.2006.032.01.11 hyman, j.d., karra, s., makedonska, n., gable, c.w., painter, s.l. & viswanathan, h.s. (2015): dfnworks: a discrete fracture network framework for modeling subsurface flow and transport.– computers & geosciences, 84, 10–19. doi: 10.1016/j.cageo.2015.08.001 jamičić, d. (1995): the role of sinistral strike-slip faults in the formation of the structural fabric of the slavonian mts. (eastern croatia).– geologia croatica, 48/2, 155–160. jamičić, d., vragović, m. & matičec, d. (1989): osnovna geološka karta sfrj 1:100 000. tumač za list daruvar (basic geological map of sfrj 1:100 000. explanatory notes for sheet daruvar). – geol. zavod, zagreb, sav. geol. zavod beograd, beograd, 55 p. jarosinski, m., beekman, f., matenco, l. & cloetingh, s. (2011): mechanics of basin inversion: finite element modelling of the pannonian basin system.– tectonophysics, 502/1–2, 121–145. doi: 10.1016/j.tecto.2009.09.015 ng, k. & santamarina, j. c. (2023): mechanical and hydraulic properties of carbonate rock: the critical role of porosity.– journal of rock mechanics and geotechnical engineering, 15/4, 814–825. doi: 10.1016/j. jrmge.2022.07.017 keegan-treloar, r., irvine, d.j., solórzano-rivas, s.c., werner, a.d., banks, e.w. & currell, m.j. (2022): fault-controlled springs: a review.– earth-science reviews, 230, 104058. doi: 10.1016/j.earscirev.2022.104058 korneva, i., cilona, a., tondi, e., agosta, f. & giorgioni, m. (2015): characterisation of the permeability anisotropy of cretaceous platform carbonates by using 3d fracture modeling: the case study of agri valley fault zones (southern italy).– italian journal of geosciences, 134/3, 396–408. doi: 10.3301/ijg.2014.26 kosović, i., briški, m., pavić, m., padovan, b., pavičić, i., matoš, b., pola, m. & borović, s. (2023): reconstruction of fault architecture in the natural thermal spring area of daruvar hydrothermal system using surface geophysical investigations (croatia).– sustainability, 15/16, 12134. doi: 10.3390/su151612134 kosović, i., matoš, b., pavičić, i., pola, m., mileusnić, m., pavić, m. & borović, s. (2024): geological modeling of a tectonically controlled hydrothermal system in the southwestern part of the pannonian basin (croatia).– frontiers in earth science. 12:1401935. doi: 10.3389/feart.2024.1401935 kruseman, g.p., de ridder, n.a. & verweij, j.m. (2000): analysis and evaluation of pumping test data.vol. 47.– international institute for land reclamation and improvement, wageningen, 378 p. lai, j., su, y., xiao, l., zhao, f., bai, t., li, y., li, h., huang, y., wang, g. & qin, z. (2024): application of geophysical well logs in solving geologic issues: past, present and future prospect.– geoscience frontiers, 15/3, 101779. doi: 10.1016/j.gsf.2024.101779 lei, q., latham, j.-p. & tsang, c.-f. (2017): the use of discrete fracture networks for modelling coupled geomechanical and hydrological behaviour of fractured rocks.– computers and geotechnics, 85, 151–176. doi: 10.1016/j.compgeo.2016.12.024 mammoliti, e., pepi, a., fronzi, d., morelli, s., volatili, t., tazioli, a. & francioni, m. (2023): 3d discrete fracture network modelling from uav imagery coupled with tracer tests to assess fracture conductivity in an unstable rock slope: implications for rockfall phenomena.– remote sensing, 15/5, 1222. doi: 10.3390/rs15051222 malvić, t. & cvetković, m. (2013): lithostratigraphic units in the drava depression (croatian and hungarian parts) – a correlation.– nafta, 64/1, 27–33. marrett, r. & allmendinger, r.w. (1990): kinematic analysis of fault-slip data.– journal of structural geology, 12/8, 973–986. doi: 10.1016/0191-8141(90)90093-e martinelli, m., bistacchi, a., mittempergher, s., bonneau, f., balsamo, f., caumon, g. & meda, m. (2020): damage zone characterization combining scan-line and scan-area analysis on a kmscale digital outcrop model: the qala fault (gozo).– journal of structural geology, 140, 104144. doi: 10.1016/j.jsg.2020.104144 mauldon, m. (1994): intersection probabilities of impersistent joints.– international journal of rock mechanics and mining sciences & geomechanics abstracts, 31/2, 107–115. doi: 10.1016/0148-9062(94)92800-2 medici, g., ling, f. & shang, j. (2023): review of discrete fracture network characterization for geothermal energy extraction.– frontiers in earth science, 11, 1–17. doi: 10.3389/feart.2023.1328397 medici, g., smeraglia, l., torabi, a. & botter, c. (2020): review of modeling approaches to groundwater flow in deformed carbonate aquifers.– groundwater, 593, 334–351. doi: 10.1111/gwat.13069 moench, a.f. (1984): double-porosity models for a fissured groundwater reservoir with fracture skin.– water resources research, 207, 831–846. doi: 10.1029/wr020i007p00831 oda, m. (1985): permeability tensor for discontinuous rock masses.– géotechnique, 35/4, 483–495. doi: 10.1680/geot.1985.35.4.483 ortner, h., reiter, f. & acs, p. (2002): easy handling of tectonic data: the programs tectonicvb for mac and tectonicsfp for windowstm.– computers & geosciences, 28/10, 1193–1200. doi: 10.1016/s00983004(02)00038-9 pamić, j., radonić, g. & pavić, g. (2003): geološki vodič kroz park prirode papuk (geological guide through the papuk nature park).– park prirode papuk, požega, 66 p. g eo lo gi a c ro at ic a 118 geologia croatica 77/2 pavić, m., kosović, i., pola, m., urumović, k., briški, m. & borović, s. (2023): multidisciplinary research of thermal springs area in topusko (croatia).– sustainability, 15/6, 5498. doi: 10.3390/ su15065498 pouraskarparast, z., aghaei, h., colombera, l., masoero, e. & ghaedi, m. (2024): fracture aperture: a review on fundamental concepts, estimation methods, applications, and research gaps.– marine and petroleum geology, 164, 106818. doi: 10.1016/j.marpetgeo.2024.106818 prelogović, e., saftić, b., kuk, v., velić, j., dragaš, m. & lučić, d. (1998): tectonic activity in the croatian part of the pannonian basin.– tectonophysics, 297/1–4, 283–293. doi: 10.1016/s00401951(98)00173-5 priest, s.d. (1993): discontinuity analysis for rock engineering. vol. 30. – springer netherlands, dordrecht, 323–324 p. doi:10.1007/978-94-0111498-1 renshaw, c.e. (1995): on the relationship between mechanical and hydraulic apertures in rough‐walled fractures.– journal of geophysical research: solid earth, 100/b12, 24629–24636. doi: 10.1029/95jb02159 romano, v., bigi, s., carnevale, f., de’haven hyman, j., karra, s., valocchi, a.j., tartarello, m.c. & battaglia, m. (2020): hydraulic characterization of a fault zone from fracture distribution.– journal of structural geology, 135, 104036. doi: 10.1016/j. jsg.2020.104036 rybach, l. & mongillo, m. (2006): geothermal sustainability-a review with identified research needs.– grc transactions, 30, 1083–1090. saftić, b., velić, j., sztano, o., juhasz, g. & ivković, ž. (2003): tertiary subsurface facies, source rocks and hydrocarbon reservoirs in the sw part of the pannonian basin (northern croatia and southwestern hungary).– geologia croatica, 56/1, 101–122. doi: 10.4154/232 schmid, s.m., fügenschuh, b., kounov, a., maţenco, l., nievergelt, p., oberhänsli, r., pleuger, j., schefer, s., schuster, r., tomljenović, b., ustaszewski, k. & van hinsbergen, d.j.j. (2020): tectonic units of the alpine collision zone between eastern alps and western turkey.– gondwana research, 78, 308–374. doi: 10.1016/j.gr.2019.07.005 schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine-carpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss journal of geosciences, 101/1, 139–183. doi: 10.1007/s00015-008-1247-3 siegel, l., goldscheider, n., petitta, m., xanke, j., andreo, b., et al. (2023): distribution, threats and protection of selected karst groundwater-dependent ecosystems in the mediterranean region.– hydrogeology journal, 31/8, 2231–2249. doi: 10.1007/s10040-023-02711-9 singhal, b.b.s. & gupta, r.p. (2010): applied hydrogeology of fractured rocks. – springer netherlands, dordrecht. doi: 10.1007/97890-481-8799-7 smeraglia, l., mercuri, m., tavani, s., pignalosa, a., kettermann, m., billi, a. & carminati, e. (2021): 3d discrete fracture network (dfn) models of damage zone fluid corridors within a reservoir-scale normal fault in carbonates: multiscale approach using field data and uav imagery.– marine and petroleum geology, 126, 104902. doi: 10.1016/j.marpetgeo.2021.104902 smith, s.a.f., bistacchi, a., mitchell, t.m., mittempergher, s. & di toro, g. (2013). the structure of an exhumed intraplate seismogenic fault in crystalline basement.– tectonophysics, 599, 29–44. doi: 10.1016/j.tecto.2013.03.031 stevanović, z. (2019): karst waters in potable water supply: a global scale overview.– environmental earth sciences, 78/23, 662. doi: 10.1007/ s12665-019-8670-9 storti, f., bistacchi, a., borsani, a., balsamo, f., fetter, m., ogata, k. (2022). spatial and spacing distribution of joints at (over-) saturation in the turbidite sandstones of the marnoso-arenacea fm. (northern apennines, italy).– journal of structural geology, 156, 104551. doi: 10.1016/j.jsg.2022.104551 szanyi, j., rybach, l. & abdulhaq, h.a. (2023): geothermal energy and its potential for critical metal extraction – a review.– energies, 16/20, 1–28. doi: 10.3390/en16207168 šikić, k. (1981): facijesi mezozoika papuckog gorja [facies of the mesozoic of mount papuk – in croatian]. – unpubl. phd thesis, faculty of science, university of zagreb. tari, g., dövényi, p., dunkl, i., horváth, f., lenkey, l., stefanescu, m., szafián, p. & tóth, t. (1999): lithospheric structure of the pannonian basin derived from seismic, gravity and geothermal data.– geological society, london, special publications, 156/1, 215–250. doi: 10.1144/gsl.sp.1999.156.01.12 tavani, s., storti, f., bausà, j. & muñoz, j. a. (2012): late thrusting extensional collapse at the mountain front of the northern apennines (italy).– tectonics, 31/4. doi: 10.1029/2011tc003059 theis, c.v. (1935): the relation between the lowering of the piezometric surface and the rate and duration of discharge of a well using ground‐ water storage.– eos, transactions american geophysical union, 16/2, 519–524. doi: 10.1029/tr016i002p00519 thiele, s.t., grose, l., samsu, a., micklethwaite, s., vollgger, s.a. & cruden, a.r. (2017): rapid, semi-automatic fracture and contact mapping for point clouds, images and geophysical data.– solid earth, 8/6, 1241–1253. doi: 10.5194/se-8-1241-2017 tomljenović, b. & csontos, l. (2001): neogene-quaternary structures in the border zone between alps, dinarides and pannonian basin (hrvatsko zgorje and karlovac basins, croatia).– international journal of earth sciences, 90/3, 560–578. doi: 10.1007/s005310000176 turner, f.j. (1953): nature and dynamic interpretation of deformation lamellae in calcite of three marbles.– american journal of science, 251/4, 276–298. doi: 10.2475/ajs.251.4.276 tziavou, o., pytharouli, s. & souter, j. (2018): unmanned aerial vehicle (uav) based mapping in engineering geological surveys: considerations for optimum results.– eng. geol., 232, 12–21. doi: 10.1016/j. enggeo.2017.11.004 united nations (2022): the united nations world water development report 2022: groundwater: making the invisible visible. unesco, paris, 225 p. urumović, k., terzić, j., kopić, j. & kosović, i. (2023): identification of aquifer and pumped well parameters using the data hidden in non-linear losses.– sustainability (switzerland), 15/14, 11170. doi: 10.3390/su151411170 ustaszewski, k., herak, m., tomljenović, b., herak, d. & matej, s. (2014): neotectonics of the dinarides-pannonian basin transition and possible earthquake sources in the banja luka epicentral area.– journal of geodynamics, 82, 52–68. doi: 10.1016/j.jog.2014.04.006 ustaszewski, k., schmid, s. m., fügenschuh, b., tischler, m., kissling, e. & spakman, w. (2008): a map-view restoration of the alpine-carpathian-dinaridic system for the early miocene.– swiss journal of geosciences, 101/suppl. 1. doi: 10.1007/s00015-008-1288-7 ustaszewski, k., kounov, a., schmid, s. m., schaltegger, u., krenn, e., frank, w. & fügenschuh, b. (2010): evolution of the adria-europe plate boundary in the northern dinarides: from continent-continent collision to back-arc extension.– tectonics, 29/6, tc6017. doi: 10.1029/2010tc002668 verbovšek, t. (2008): estimation of transmissivity and hydraulic conductivity from specific capacity and specific capacity index in dolomite aquifers.– journal of hydrologic engineering, 13/9, 817–823. doi: 10.1061/(asce)1084-0699(2008)13:9(817) voeckler, h. & allen, d. m. (2012): estimating regional-scale fractured bedrock hydraulic conductivity using discrete fracture network (dfn) modeling.– hydrogeology journal, 20/6, 1081–1100. doi: 10.1007/ s10040-012-0858-y wang, x. (2005): stereological interpretation of rock fracture traces on borehole walls and other cylindrical surfaces.– virginia techp. worthington, s.r.h., foley, a.e. & soley, r.w.n. (2019): transient characteristics of effective porosity and specific yield in bedrock https://doi.org/10.1016/j.enggeo.2017.11.004 https://doi.org/10.1016/j.enggeo.2017.11.004 g eologia c roatica 119kosović et al.: hydrogeological parameterisation of the daruvar thermal aquifer: integration of fracture network analysis and well testing aquifers.– journal of hydrology, 578, 124129. doi: 10.1016/j.jhydrol.2019.124129 zambrano, m., tondi, e., korneva, i., panza, e., agosta, f., janiseck, j.m. & giorgioni, m. (2016): fracture properties analysis and discrete fracture network modelling of faulted tight limestones, murge plateau, italy.– italian journal of geosciences, 135/1, 55–67. doi: 10.3301/ijg.2014.42 zeeb, c., gomez-rivas, e., bons, p. d. & blum, p. (2013): evaluation of sampling methods for fracture network characterization using outcrops.– aapg bulletin, 97/9, 1545–1566. doi: 10.1306/02131312042 zhang, l. & einstein, h. h. (1998): estimating the mean trace length of rock discontinuities.– rock mechanics and rock engineering, 31/4, 217–235. doi: 10.1007/s006030050022 url 1: https://earth.google.com/web/@45.53570123,17.29653113,232.316029 05a,6291.71769557d,35y,-12.560923h,2.44982084t,0r/data=ogmkata (visited april 2024) url 2: https://www.pix4d.com/product/pix4dmapper-photogrammetry-software/ (visited april 2024) url 3: https://www.cloudcompare.org/ (visited april 2024) url 4: https://doi.org/10.5281/zenodo.7890077 (visited april 2024) url 5: https://www.mathworks.com/ (visited april 2024) url 6: http://qgis.org (visited april 2024) url 7: https://doi.org/10.5281/zenodo.11032168 (visited april 2024) url 8: https://www.petex.com/products/move-suite/move/ (visited april 2024) https://earth.google.com/web/@45.53570123,17.29653113,232.31602905a,6291.71769557d,35y,-12.560923h,2.44982084t,0r/data=ogmkata https://earth.google.com/web/@45.53570123,17.29653113,232.31602905a,6291.71769557d,35y,-12.560923h,2.44982084t,0r/data=ogmkata https://www.pix4d.com/product/pix4dmapper-photogrammetry-software/ https://www.pix4d.com/product/pix4dmapper-photogrammetry-software/ https://www.cloudcompare.org/ https://doi.org/10.5281/zenodo.7890077 https://www.mathworks.com/ http://qgis.org https://doi.org/ https://zenodo.org/doi/10.5281/zenodo.11032168 https://www.petex.com/products/move-suite/move/ g eo lo gi a c ro at ic a 120 geologia croatica 77/2 supplementary table 1. average orientations of the measured carbonate beds with computed fold axes. strata orientation data dip direction (°) dip angle (°) strike fold axis orientation dip direction (°) dip angle (°) so1 29 57 80 147-327 138 42 so2 226 88 136-316 so3 39 310 66 40-220 228 16 so4 138 88 48-228 supplementary table 2. average orientation of the three fracture sets in brq. fracture system data dip direction (°) dip angle (°) strike fs1a 31 113 81 23-203 fs1b 28 288 82 18-198 fs2 42 100 45 10-190 fs3a 32 22 85 112-292 fs3b 22 338 73 68-248 supplementary table 3. mean geometrical properties of the observed fault planes with calculated kinematic indicators and parameters. fault planes (fault types: r – reverse; n – normal; ssf – strike-slip were grouped following their geometrical properties. orientations of the pand t-axes are based on constructed synthetic structural beach-ball diagrams (fig. 6). fault group subset data dip direction (°) dip angle (°) pitch (°) striation p-axis t-axis trend (°) plunge (°) trend (°) plunge (°) trend (°) plunge (°) rf rfa 20 128 56 72 115 43 128 12 336 76 rfb 289 36 76 261 66 nf nfa 11 153 41 81 126 65 14 87 325 11 nfb 319 50 79 211 68 ssf-1 ssf-1a 10 150 52 24 78 20 13 17 275 23 ssf-1b 45 73 17 308 16 ssf-2 ssf-2a 9 113 66 18 67 11 252 1 345 30 ssf-2b 211 71 19 124 17 supplementary table 4. average orientations of the main discontinuity sets in the quarry sections (qs2-qs6) and amount of data constituting the sets. quarry section set data dip direction (°) dip angle (°) strike qs2 d1a 20 315 76 45-225 d1b 17 116 83 26-206 d2a 23 248 53 158-338 d2b 15 277 57 137-317 d3 21 272 87 2-182 qs 3a d1a 132 304 68 34-214 d1b 43 285 83 15-195 d2a 140 241 75 151-331 d2b 74 240 41 150-330 qs 3b d1a 124 329 70 59-239 d1b 73 303 77 33-213 d2 115 258 72 168-348 qs 4 d1a 103 328 70 58-238 d1b 86 304 69 34-214 d2 89 254 72 164-344 qs 5 d1 182 308 71 38-218 d2 115 267 72 177-357 qs 6 d1a 16 331 70 61-241 d1b 9 313 72 43-223 d2a 5 270 60 0-180 d2b 8 265 81 175-355 g eologia c roatica 121kosović et al.: hydrogeological parameterisation of the daruvar thermal aquifer: integration of fracture network analysis and well testing supplementary table 5. results of statistical analysis for the horizontal (h) and vertical (v) discontinuity network. discontinuity set h fracture network v total number of fractures 352 260 % censored 11.08 20 data fit data fit mean 3.5306 3.8836 3.6673 5.0660 median 2.0381 2.3812 1.8787 2.4461 mode 0.2029 0.8952 0.3225 0.5703 b5 0.5387 0.4680 0.4375 0.3361 b95 12.4790 12.1160 13.1371 17.8025 std 4.5250 5.0036 4.5258 9.1879 var 20.4755 25.0358 20.4825 84.4173 supplementary figure 1. statistical distribution of the heights of the horizontal (h) and vertical (v) fracture network (quarry section 3a). statistical analysis of the main geometrical parameter (height) was performed by using fracability. supplementary table 6. input parameters used for the construction of the dfn model of the qs3a section. the measurement units of the parameters are reported in brackets. the obtained model is shown in fig. 10. parameter set h set v dip direction 240.86 295.86 dip 64.92 74.79 fisher k 13.53 18.83 height – mean (m) 3.88 5.06 height – std (m) 5.00 9.18 length/height ratio 0.25 0.25 sum of fractures heights (m) 1244.96 961.19 p21 (m/m2) 0.47 0.37 p32 (m2/m3) 1.98 1.18 aperture (mm) 4.15 4.15 g eo lo gi a c ro at ic a 122 geologia croatica 77/2 supplementary figure 2. distributions of porosity (φ) obtained for the tested aperture values and employing the different methodological approaches. g eologia c roatica 123kosović et al.: hydrogeological parameterisation of the daruvar thermal aquifer: integration of fracture network analysis and well testing supplementary figure 3. distributions of permeability (k) obtained for the tested aperture values and employing the different methodological approaches. g eo lo gi a c ro at ic a 124 geologia croatica 77/2 supplementary table 7. statistical distributions of the porosity (φ) in the dfn models conducted considering different methodological approaches for assigning the fracture aperture and using different aperture values. aperture (mm) porosity – φ (%) mean median standard deviation min max skewness kurtosis 10th perc. 25th perc. 50th perc. 75th perc. 90th perc. co ns ta nt 0.1 0.03 0.03 0.02 0.00 0.24 0.91 3.85 0.00 0.01 0.03 0.05 0.06 0.2 0.06 0.05 0.05 0.00 0.47 0.91 3.85 0.00 0.02 0.05 0.09 0.13 0.5 0.15 0.13 0.12 0.00 1.18 0.91 3.85 0.00 0.05 0.13 0.23 0.32 1 0.30 0.26 0.25 0.00 2.37 0.91 3.85 0.00 0.11 0.26 0.45 0.64 2 0.61 0.51 0.49 0.00 4.73 0.91 3.85 0.00 0.22 0.51 0.90 1.29 5 1.52 1.28 1.23 0.00 11.83 0.91 3.85 0.00 0.55 1.28 2.25 3.21 10 3.04 2.56 2.46 0.00 23.65 0.91 3.85 0.00 1.10 2.56 4.50 6.43 ro ot s qu ar e le ng th 0.1 0.05 0.05 0.04 0.00 0.43 0.97 4.00 0.00 0.02 0.05 0.08 0.11 0.2 0.11 0.09 0.09 0.00 0.86 0.97 4.00 0.00 0.04 0.09 0.16 0.23 0.5 0.27 0.23 0.22 0.00 2.14 0.97 4.00 0.00 0.09 0.23 0.40 0.57 1 0.53 0.46 0.44 0.00 4.28 0.97 4.00 0.00 0.18 0.46 0.79 1.14 2 1.07 0.91 0.88 0.00 8.57 0.97 4.00 0.00 0.36 0.91 1.59 2.28 5 2.67 2.29 2.21 0.00 21.42 0.97 4.00 0.00 0.91 2.29 3.97 5.70 10 5.34 4.57 4.42 0.00 42.84 0.97 4.00 0.00 1.81 4.57 7.94 11.41 le ng th 0.1 0.07 0.05 0.06 0.00 0.53 1.09 4.34 0.00 0.02 0.05 0.10 0.14 0.2 0.13 0.11 0.11 0.00 1.07 1.09 4.34 0.00 0.04 0.11 0.20 0.29 0.5 0.33 0.27 0.28 0.00 2.67 1.09 4.34 0.00 0.10 0.27 0.49 0.72 1 0.65 0.55 0.57 0.00 5.35 1.09 4.34 0.00 0.19 0.55 0.98 1.44 2 1.31 1.09 1.14 0.00 10.69 1.09 4.34 0.00 0.39 1.09 1.95 2.88 5 3.27 2.73 2.85 0.00 26.73 1.09 4.34 0.00 0.97 2.73 4.88 7.19 10 6.54 5.47 5.70 0.00 53.46 1.09 4.34 0.00 1.93 5.47 9.75 14.38 supplementary table 8. statistical distribution of the permeability (k) in the dfn models conducted considering different methodological approaches for assigning the fracture aperture and using different aperture values. aperture (mm) permeability – k (d) mean median standard deviation min max skewness kurtosis 10th perc. 25th perc. 50th perc. 75th perc. 90th perc. co ns ta nt 0.1 2.5e-1 2.2e-1 2.e-1 0.00 1.9 0.85 3.69 0.00 9.3e-2 2.2e-1 3.8e-1 5.3e-1 0.2 2 1.7 1.6 0.00 1.5e1 0.85 3.69 0.00 7.4e-1 1.7 3 4.3 0.5 3.2e1 2.7e1 2.5e1 0.00 2.3e2 0.85 3.69 0.00 1.2e1 2.7e1 4.7e1 6.6e1 1 2.5e2 2.2e2 2.e2 0.00 1.9e3 0.85 3.69 0.00 9.3e1 2.2e2 3.8e2 5.3e2 2 2.e3 1.7e3 1.6e3 0.00 1.5e4 0.85 3.69 0.00 7.4e2 1.7e3 3.e3 4.3e3 5 3.2e4 2.7e4 2.5e4 0.00 2.3e5 0.85 3.69 0.00 1.2e4 2.7e4 4.7e4 6.6e4 10 2.5e5 2.2e5 2.e5 0.00 1.9e6 0.85 3.69 0.00 9.3e4 2.2e5 3.8e5 5.3e5 ro ot s qu ar e le ng th 0.1 1.6 1.2 1.5 0.00 1.4e1 1.28 4.99 0.00 3.8e-1 1.2 2.3 3.6 0.2 1.2e1 9.8e 1.2e1 0.00 1.1e2 1.28 4.99 0.00 3.1 9.8 1.9e1 2.9e1 0.5 2.e2 1.5e2 1.8e2 0.00 1.7e3 1.28 4.99 0.00 4.8e1 1.5e2 2.9e2 4.5e2 1 1.6e3 1.2e3 1.5e3 0.00 1.4e4 1.28 4.99 0.00 3.8e2 1.2e3 2.3e3 3.6e3 2 1.2e4 9.8e3 1.2e4 0.00 1.1e5 1.28 4.99 0.00 3.1e3 9.8e3 1.9e4 2.9e4 5 2.e5 1.5e5 1.8e5 0.00 1.7e6 1.28 4.99 0.00 4.8e4 1.5e5 2.9e5 4.5e5 10 1.6e6 1.2e6 1.5e6 0.00 1.4e7 1.28 4.99 0.00 3.8e5 1.2e6 2.3e6 3.6e6 le ng th 0.1 3.8 2.2 4.8 0.00 6.1e1 2.40 11.22 0.00 4.7e-1 2.2 5.4 9.7 0.2 3.1e1 1.7e1 3.8e1 0.00 4.9e2 2.40 11.22 0.00 3.8 1.7e1 4.3e1 7.8e1 0.5 4.8e2 2.7e2 6.e2 0.00 7.7e3 2.40 11.22 0.00 5.9e1 2.7e2 6.7e2 1.2e3 1 3.8e3 2.2e3 4.8e3 0.00 6.1e4 2.40 11.22 0.00 4.7e2 2.2e3 5.4e3 9.7e3 2 3.1e4 1.7e4 3.8e4 0.00 4.9e5 2.40 11.22 0.00 3.8e3 1.7e4 4.3e4 7.8e4 5 4.8e5 2.7e5 6.e5 0.00 7.7e6 2.40 11.22 0.00 5.9e4 2.7e5 6.7e5 1.2e6 10 3.8e6 2.2e6 4.8e6 0.00 6.1e7 2.40 11.22 0.00 4.7e5 2.2e6 5.4e6 9.7e6 g eologia c roatica 125kosović et al.: hydrogeological parameterisation of the daruvar thermal aquifer: integration of fracture network analysis and well testing supplementary figure 4. interpretation of the step-drawdown test results conducted in the dar 1 well. supplementary table 9. hydrogeological parameters obtained from the interpretation of the pumping test using dar 1 as exploitation well and d 1 and ds 1 as observation wells. the estimated parameters are: transmissivity (t), storativity (s), hydraulic conductivity anisotropy ratio (kz/kr), and saturated thickness (b). parameter whole test constant test t (m2/s) 3.82e-2 3.46e-2 s (-) 2.05e-3 1.14e-3 kz/kr (-) 6.81e-3 1.98e-2 b (m) 61.53 68.42 2019 | 72/1 | 51–79 | 6 figs. | 8 tabs. | suppl. tabs. 7 | suppl. figs. 2 | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction lignites of upper miocene age are the most important energy source in serbia. almost all lignite production (90%) from the kolubara and kostolac basins is used in thermal power plants (tpp), (eps, 2018). information on the content, distribution and mode of occurrence of major and trace elements, especially po­ tentially toxic and radioactive ones, are of great importance, if coal is used for combustion in a tpp. many studies of trace ele­ ments contained in coal have been carried out in order to under­ stand and evaluate their mode of occurrence, as well as their behaviour during combustion (e.g., davidson, 2000; finkel­ man et al., 2018; meij, 1995; swaine, 1990; swaine & goodarzi, 1995; ward, 2016; yudovich, 1978; yudo­ vich et al., 1985; yudovich & ketris, 2002, 2005b). the mode or form of occurrence of trace elements may control po­ tential hazardous effects to human health (finkelman et al., 2002) and the environment. numerous studies performed in se europe on greek (chatziapostolou et al., 2006; gentzis et al., 1996, 1997; georgakopoulos, 2001; filippidis et al., 1996; foscolos et al., 1998; koukouzas et al., 2010), bulgarian (kostova & zdravkov, 2007; vassilev & vasileva, 1998, 2009; vassilev et al., 2001, 2009; vassi­ leva & vassilev, 2005) and turkish lignites (gürdal, 2011; karayigit & gayer, 2000; karayigit et al., 2000; 2001; palmer et al., 2004; sutcu & karayigit, 2015; vassilev et al., 2005) of similar age and rank as the kovin lig­ nite, have focused on the mineral matter and major and trace el­ ements contents. distribution of major and trace elements in the kovin lignite (serbia) dragana životić1, olga cvetković2, predrag vulić1, ivan gržetić3, vladimir simić1, konstantin ilijević3, biljana dojčinović2, suzana erić1, bogdan radić4, sanja stojadinović2 and snežana trifunović3 1 university of belgrade, faculty of mining and geology, đušina 7, 11000 belgrade, serbia; (corresponding author: dragana.zivotic@rgf.bg.ac.rs; tel: +381 11 3219 251; fax: +381 11 3235 537) 2 center of chemistry, ichtm, studentski trg 12–16, 11000 belgrade, serbia 3 university of belgrade, faculty of chemistry, studentski trg 12–16, 11000 belgrade, serbia 4 kovin coal mine, cara lazara 85, 26220 kovin, serbia doi: 10.4154/gc.2019.06 abstract a geochemical and mineralogical study was performed on lignite samples from the upper miocene kovin deposit, hosting three coal seams. the kovin lignite is characterized by high moisture content, medium to high ash yield, medium to high sulphur content and a relatively low gross and net calorific value. the mineralogical composition, and major and trace element contents were determined by x-ray diffraction, scanning electron microscopy with energy dispersive xray spectroscopy (sem-eds) analyses, and inductively coupled plasma optical emission spectrometry (icp-oes). the most abundant minerals in all lignite samples from the three coal seams are clays (illite/smectite), silicates (quartz, plagioclase), sulphates (gypsum/anhydrite) and carbonate (calcite). the other iron-rich minerals are sulphides, oxides and hydroxides (pyrite, magnetite, haematite, and limonite). in general, mineral matter in the matrix coal consists of illite/ smectite and quartz, while xylite-rich coals, apart from illite/smectite, have a higher content of sulphates and fe-oxide/hydroxide minerals. the lignite from the kovin deposit is enriched in as, cd, co, cr, cu, ga, li, mn, mo, ni, pb, v, zn, gd, tb, er and lu in comparison with the clarke values for brown coals. the statistical analysis of bulk compositional data shows inorganic affinity for the majority of the major and trace elements and possible association with pyrite, illite/ smectite and calcite. the upper miocene kovin lignite deposit is located about 50 km east of belgrade (fig. 1). together with the kostolac basin, it is a part of the unique coal basin separated by the danube river (mitrović et al., 2016), which forms the southern boundary of the kovin deposit. the kovin deposit is divided into two fields: the western field “a”, and the eastern field “b”, 16.3 km2 and 23.7 km2, in areal extent respectively. according to the geological re­ port of the kovin deposit, the lignite resources and reserves are currently estimated at 275 mt (mitrović et al., 2016). subaque­ ous exploitation of lignite (below the danube river) in the offshore zone of the “a” field, named “experimental exploitation field” (eef) began in 1991, and is still active. since 1991, the kovin mine has produced about 5 mt of lignite, with an annual produc­ tion of ~ 300,000 t. geological exploration of the wider area of the kovin de­ posit, including the kostolac coal basin, began in the late 19th century. the upper miocene (pontian) age of the coal­bearing sediments was confirmed by palaeontological studies (pav lo­ vić, 1959; spajić­miletić, 1960, 1969; stevanović, 1951). the distribution of palynomorph assemblages in the lignite from the eef field (milivojević & životić, 2006; životić et al., 2007) suggests that decay­resistant gymnosperm (conife­ rous) trees and bushes played an important role in lignite forma­ tion. previous petrographic investigations (ercegovac et al., 2006; životić et al., 2005, 2007) performed on samples from several boreholes from the i and ii coal seam, showed that the lignite from the kovin deposit is a typical humic coal with vari­ able huminite, liptinite and inertinite contents, and a mean ran­ article history: received june 08, 2018 revised manuscript accepted december 12, 2018 available online february 15, 2019 keywords: kovin deposit, lignites, major and trace elements, mineral composition g eo lo gi a c ro at ic a geologia croatica 72/152 dom huminite reflectance of 0.30±0.03 (ercegovac et al., 2006). recent petrographic and organic geochemical investiga­ tions (mitrović et al., 2016, 2017) confirm the variation in maceral and lithotype composition in both fields and all three seams with diagenetic alteration governed by chemoautotrophic­, methanotrophic­ and heterotrophic bacteria. the same samples were used to determine the content and distribution of major and trace elements in the coal. the aim of this study is to present the content and mode of occurrence of major and trace elements in coal from the kovin deposit in order to assess their behaviour in case of exploitation for electric power generation. 2. geological settings the area of the kovin deposit consists of palaeozoic schist, ter­ tiary and quaternary sediments (fig. 1). the basement of the kovin deposit is formed of devonian low­grade schist overlain by neogene sediments. the kovin deposit together with the kostolac basin was formed in the pannonian basin system in shallow lacustrine, delta plain and fluvial environments. during the late miocene it became in­ creasingly widespread as lake pannon (e.g. magyar et al., 1999, 2013; sztanó et al., 2013) filled with coal­bearing sediments in the central part of serbia. the total thickness of neogene sediments is estimated at 1000 m. the neogene units of the kovin deposit figure 1. location of the kovin deposit (a, b) and simplified geological map (c) of the kovin deposit with sample locations (modified after basic geologic map of serbia, section l34-127 and l34-115; http://geoliss.mre.gov.rs/ogk/rastersrbija/). g eologia c roatica životić et al.: distribution of major and trace elements in the kovin lignite (serbia) 53 consist of: a) sarmatian (middle miocene) shallow brackish­ma­ rine sediments; b) pannonian (late miocene) marly sediments; c) pontian (late miocene; rögl, 1996) shallow, caspi­brackish to fresh water sediments; d) lower pliocene fresh water clastic sedi­ ments, as described in detail in mitrović et al. (2016). in the upper miocene (pontian) clastic coal­bearing series of the kovin deposit, three coal seams are hosted (mitrović et al., 2016) namely iii (the oldest), ii and i (the youngest). seam iii was found in the eastern part of the b field with a total thick­ ness from a few to 48.7 metres (including interbedded waste rock). coal seam ii developed through the entire kovin deposit, and in the eastern part it is uniform, but towards the west it splits into several coal layers. total seam thickness is variable, up to 7 m. the youngest, coal seam i has been explored in the southern part of the a field (eef; fig. 1). in the b field and the eastern, south­eastern and south part of the a field, it is more or less uni­ form, but towards the north­west it splits into two coal layers (upper­ia and lower­ib) with a total thickness of up to 15 m. tectonic features of the pontian sediments are relatively uni­ form in the major part of the deposit; coal seams dip at low angles (5–7o) to the northwest. in the central part of deposit coal seams form an antiform due to post­sedimentary faulting, causing ero­ sion of coal seam i in the central part of the deposit between fields a and b. one of the most important normal faults is located in the western part of the b field (fig. 1). 3. samples and methods 3.1. sample collection the forty­four lignite samples were collected from four bore­ holes, gd­601 and gd­603 from the a field, and kb­79 and kb­ 91 from the b field, kovin deposit, as described in detail in mitrović et al. (2016, 2017; fig. 1; table s­i of the supplemen­ tary material). the samples represent different lithotypes and parts of coal seams i, ii and iii (figs. 2 & 3). 3.2. lithotypes and maceral analyses the identification of lignite lithotypes (table 1; figs. 2 & 3) fol­ lowed the nomenclature adopted by the iccp (1993) and tay­ lor et al. (1998). polished blocks for maceral analyses were prepared accord­ ing to iso 7404­2 (2009) and performed according to iso 7404­3 (2009). the identification of macerals followed the nomenclature developed by the international committee for coal and organic petrology for huminite (sykorova et al., 2005), liptinite (pic­ kel et al., 2017) and inertinite (iccp, 2001). 3.3. proximate and ultimate analyses the proximate and ultimate analyses of lignite samples were con­ ducted using a vario el iii chns/o elemental analyzer, ele­ mentar analysensysteme gmbh, according to several standards for the determination of analytical moisture (srps b.h8.390:1987, 1987), total moisture (srps b.h8.338:1986, 1986), ash yield (iso 1171, 1997) and volatile matter (srps b.h8.317:1988, 1988). ca­ lorific value measurements were performed on an ika­calorim­ eter adiabatic c 400, following the standard procedure (srps b.h8.318:1972, 1972). 3.4. x-ray diffraction (xrd) and sem-eds analysis mineralogical analysis of forty­two (without the 28/91 and 31/91 samples) ash samples, heated to 450°c was carried out using table 1. the maceral composition (vol.%, mmf.) after mitrović et al. (2016). subgroup/group i seam ii seam iii seam min-max x̅ min-max x̅ min-max x̅ telohuminite 20.23–65.52 45.67 29.96–72.01 45.57 18.49–61.18 36.12 detrohuminite 17.19–66.02 35.94 14.43–49.34 36.25 18.61–66.00 39.39 gelohuminite 3.50–12.86 7.77 2.68–12.54 7.66 5.76–13.96 9.07 huminite 81.41–95.05 89.38 81.45–95.03 89.48 74.49–94.87 84.58 liptinite 2.04–7.06 4.30 2.98–7.44 4.84 1.13–4.86 3.32 inertinite 2.03–14.82 6.32 1.99–14.03 5.68 1.64–24.38 12.10 min – minimum; max – maximum; x̅ – arithmetic mean value; mmf – mineral matter free basis. table 2. results of proximate and ultimate analyses of the kovin lignite. parameter i seam ii seam iii seam min-max x̅ s min-max x̅ s min-max x̅ s war (wt.%) 34.57–52.90 44.83 6.33 14.42–52.48 41.33 11.17 11.79–54.13 37.91 16.38 wan (wt.%) 5.84–15.24 9.36 2.60 2.95–11.70 6.50 2.74 1.90–2.73 6.80 3.78 adb (wt.%) 12.58–52.90 31.95 13.70 13.85–68.60 36.26 18.30 8.66–78.20 39.53 25.32 sdb (wt.%) 0.82–4.40 2.20 0.99 0.22–3.34 1.60 0.92 0.21–2.13 1.22 0.59 vdb (wt.%) 27.95–47.48 39.46 6.85 12.10–50.26 36.23 10.79 9.67–46.71 30.88 14.19 q daf g (mj/kg) 21.00–28.30 24.29 1.82 16.90–27.80 23.48 3.09 15.70–26.30 23.00 3.71 qdaf n (mj/kg) 20.10–27.20 23.26 1.82 16.30–26.70 22.42 3.02 14.30–25.30 22.02 3.75 cdaf (wt.%) 56.48–73.24 64.78 3.92 52.25–74.02 64.40 4.73 55.23–70.45 64.96 5.18 hdaf (wt.%) 2.95–6.53 4.64 0.81 2.96–6.31 4.91 0.75 2.61–6.65 4.55 1.08 ndaf (wt.%) 0.79–1.89 1.19 0.27 0.64–1.39 1.05 0.20 0.79–1.51 1.16 0.20 odaf (wt.%) 20.09–33.73 25.90 3.26 17.06–40.42 27.05 5.00 21.79–41.09 27.38 6.09 war – moisture content, as received basis, %; wan – analytical moisture content, %; adb – ash content, dry basis, %; sdb – total sulphur content, dry basis wt.%; vdb – volatile matter, dry basis wt.%; q daf g – gross calorific value, dry, ash-free basis, mj/kg; q daf n – net calorific value, dry, ash-free basis, mj/kg; cdaf – carbon content, dry, ash-free basis, %; hdaf – hidrogen content, dry, ash-free basis, %; ndaf – nitrogen content, dry, ash-free basis; odaf – oxigen content, dry, ash-free basis, %; x̅ – arithmetic mean value; min – minimum; max – maximum; s – standard deviation. note: values of parameters for individual samples are given in table s-ii of the supplementary material to this paper. g eo lo gi a c ro at ic a geologia croatica 72/154 figure 2. macropetrographic profiles of boreholes gd-601 (a) and gd-603 (b) in the a field lignite and the vertical distribution of minerals and major elements in coal. g eologia c roatica životić et al.: distribution of major and trace elements in the kovin lignite (serbia) 55 x­ray powder diffraction (xrpd). analysis was performed on a philips pw 1710 powder diffractometer with cukα1,2 = 1.54178 å radiation and a 40 kv, 30 ma. the xrd pattern was recorded over a 2θ interval of 4–70°, with a step size of 0.02° and the fixed counting time of 1 s per step. x­ray diffractograms of 42 samples were subjected to quantitative mineralogical analysis using the fullprof computer program (rodríguez­carvajal, 1993) based on the principles for diffractogram profiling set out by ri­ etveld (1969). no quantification of the amorphous and sul­ phide phases was undertaken. the mineral composition and distribution of some elements in the minerals were investigated in five representative samples figure 3. macropetrographic profiles of boreholes kb-79 (a) and kb-91 (b) in the b field lignite and vertical distributions of minerals and major elements in coal. g eo lo gi a c ro at ic a geologia croatica 72/156 (53/603, 56/603, 3/79, 17/79 and 31/79) using a jeol jsm­6610lv scanning electron microscope (30 kv accelerating voltage) equipped with an energy­dispersive x­ray spectrometer (sem­ eds; x­max large area analytical silicon drift connected with incaenergy 350 microanalysis system). after the maceral ana­ lysis, polished blocks were coated with a thin gold film in order to obtain a higher quality secondary electron image for sem and edx examination. 3.5. inductively coupled plasma optical emission spectrometry analysis (icp-oes) the contents of major and trace elements were determined by in­ ductively coupled plasma – optical emission spectrometry (icp­ oes). icp­oes measurements were performed using a thermo scientific icap 6500 duo icp (thermo fisher scientific, cam­ bridge, united kingdom). the digestion of lignite samples was performed on an advanced microwave digestion system (ethos 1, milestone, italy) using a hpr­1000/10s high pressure segmented rotor. for total dissolution, about 240–390 mg of lig­ nite sample was precisely weighed and mixed with 6 ml hno3 (65%) and 2ml h2o2 (30%), then heated by microwave energy for 30 min. the temperature was gradually raised to 220 ºc in the first 10 min, remained at 220 ºc in the next 20 min, and then de­ creased rapidly to room temperature. after cooling, the vessels were opened, 4 ml of h3po4 (85%) and 2 ml hf (40%) were added and the second phase of microwave digestion was per­ formed under the same temperature program as the first one. all reagents were analytical grade reagents purchased from carlo erba, italy. two multi­elemental plasma standard solutions (multi­element plasma standard solution 4, specpure®, 1000 µg/ml and semiquantitative standard 1, specpure®, 10 µg/ml) and four single plasma standard solutions (silicon, specpure®, 1000µg/ml; vanadium, specpure®, 1000µg/ml, titanium, spec­ pure®, 1000µg/ml and molybdenum, specpure®, 1000µg/ml) certified by alfa aesar gmbh & co kg, germany, were used to prepare calibration solutions for icp­oes measurements. the validity of the all the analytical methods results were provided using the crm and evaluation of the test results in accordance to the reproducibility for each tested parameter, in accordance with the requirements of the srps iso/iec 17025:2006 (2006). 4. results 4.1. lithotypes and maceral composition the results of lithotypes and maceral analyses were taken from previous research (mitrović et al., 2016). stratified matrix coal (table s­i of the supplementary material; figs. 2, 3) predomi­ nates in the upper and the lower part of seam iii, while xylite­rich coal (iccp, 1993) predominates in the central part of the seam. mineral­rich coal is present in thin layers near the roof of the seam. stratified matrix coal in seam ii predominates in the whole seam, while xylite­rich coal is present in thin layers near the up­ per and lower parts of the seam. a mixture of mineral­rich and matrix coal is present in thin layers near the floor of the seam. stratified matrix coal in seam i predominates in the whole seam, while xylite­rich coal is present in thin layers in the upper and lower parts of the seam in field b, and in the upper part of the up­ per bench (ia) in field a. huminite is the prevailing maceral group in all seams with telohuminite and detrohuminite as the most abundant maceral subgroups (mitrović et al., 2016; table 1). the content of lip­ tinite is low with liptodetrinite and sporinite as the most abundant macerals (mitrović et al., 2016). inertinite content is low in the seam i and ii, with its maximum in seam iii, with inerto­ detrinite, fusinite and semifusinite being the most abundant ma­ cerals. clays are the most abundant minerals, while pyrite, car­ bonates and other minerals are less abundant. 4.2. proximate and ultimate analyses the kovin lignite is characterized by its high moisture content, medium to high ash yield, high volatile matter, higher sulphur content and relatively low gross and net calorific value (table 2; table s­ii of the supplementary material). the total moisture of most samples is variable from 34.57–52.90%, 14.42–52.48% and 11.79–54.13%, for coal seams i, ii and iii, respectively (moisture being dependant on the freshness of the analysed sample mate­ rial – as received basis). the ash content (dry basis) ranges from 12.58 to 52.90%, 13.85 to 68.60%, 8.66 to 78.20%, for coal seams i, ii and iii respectively, which is on average from low (<10%) to a very high ash level (>50%). most of the kovin lignite contains a low to medium sulphur (dry basis) content, whereas four samp­ les contain a higher sulphur content of more than 3%. coal seam i has a medium (1–3%) to high sulphur content (>3%), with the highest content (4.40% in sample 31/91; table s­ii of the supple­ mentary material) in the bottom part of the seam in the b field. total sulphur content in coal seam ii ranges from medium to low, rarely high content. the highest total sulphur content at 3.12% (sample 37/91) has been detected in the b field. coal seam iii has a medium to low sulphur content. the volatile matter on dry ba­ sis (vdb; table 2) of the kovin lignite is typically at a high level of 27.95–47.48%, 12.10–50.29% and 9.67–46.71%, for coal seams i, ii and iii, respectively. based on the dry and ash free basis (daf), values of gross and net calorific value are typical for lignite. coal seam i has a higher average net calorific value (23.26 mj/kg) compared to seam ii (22.42 mj/kg), and seam iii (22.02 mj/kg). the slight variation of this parameter is detectable between lithotypes and fields. it is obvious that mineral­rich coal has the higher ash content and lower gross and net calorific value (table s­ii of the supplemen­ tary material). the c contents (daf) are similar in all three seams, averag­ ing at 64.78%, 64.40% and 64.96% for coal seams i, ii and iii, respectively (table i). the average h contents (daf) are 4.64%, 4.91% and 4.55% for coal seams i, ii and iii, respectively, while the respective o contents (daf) are 25.90%, 27.05% and 27.38%. the n content (daf) ranges from 0.64% to 1.89% in all samples. 4.3. mineralogy the kovin lignite is characterized by medium (10–30%) to very high (>50%) mineral matter contents. xrd analyses of lignite ashes show that mineral matter in the coal seam i (table 3; figs. 2, 3; table s­ii of the supplementary material; figs. s1, s2 of the supplementary material) consists mainly of anhydrite (13.10– 52.28%), quartz (3.97–52.61%) and illite/smectite (12.05–46.66%) with variable proportions of haematite (4.37–17.13%), plagioclase (0.67–10.96%) and calcite (0.01–25.30%). it should be noted that smectite cannot be identified on xrd powder diffractograms af­ ter heating/burning at 450oc, so in further text illite/smectite will always include both phases. also, the content of anhydrite and haematite should be carefully taken into account, because they could be formed during the ashing process (ward, 2002, 2016). quartz is more abundant in the a field, while illite/smectite domi­ nates in the b field. the mineral matter in coal seam ii ash con­ sists of illite/smectite (14.79–73.55%), quartz (8.62–57.19%) and g eologia c roatica životić et al.: distribution of major and trace elements in the kovin lignite (serbia) 57 anhydrite (3.16–54.64%) with variable amounts of haematite (0.25–19.59%), plagioclase (0.49–11.99%) and calcite (0.39– 20.33%). illite/smectite and quartz are almost equally abundant in the a field, while illite again prevails in the b field. the most abundant mineral matter in coal seam iii ash is quartz (6.03– 69.30%), while illite/smectite (11.68–30.77%), anhydrite (0.59– 47.67%), plagioclase (1.68–17.21%), calcite (0.07–28.38%) and haematite (0.13–5.73%) are less abundant. sem­eds examination revealed that the most abundant minerals in all the studied lignite samples are clays (illite/smec­ tite; table 4; fig. 4), silicates (quartz, plagioclase), sulphate (gyp­ sum/anhydrite) and carbonate (calcite). the other iron­rich mine­ rals are sulphides, oxides and hydroxides (pyrite, magnetite, haematite, and limonite) and plagioclase. minor minerals such as rutile, ilmenite, k­feldspar (albite, orthoclase), and mica, were detected in all coal seams. in addition, in seam i, barite, chlorite, epidote, allanite and zircon were also detected. samples from seam ii contain sphalerite, galena, siderite, dolomite, ankerite and monazite, while in coal seam iii barite and monazite were found. the silicate and aluminosilicate minerals are common con­ stituents of the inorganic matter in kovin lignites and include mainly quartz, illite/smectite, rarely chlorite and plagioclase, and more rarely, mica (biotite, muscovite), and k­feldspar (fig. 4). quartz is a major inorganic component of the kovin lignites, es­ pecially in coal seam iii (table 4). some parts of seams i and ii have very high quartz contents. it is recognized as single angular to semi­rounded grains of predominantly detrital origin (ward, 2002), but authigenic crystals were also determined. epigenetic quartz, along with clay minerals, pyrite, and carbonates, was formed within cleats and fractures in the organic matrix, as a re­ sult of the circulation of meteoric waters. the clay minerals, represented by illite/smectite and chlorite, are typical constituents of the inorganic matter, especially in coal seam ii. they are mostly of detrital origin (ward, 2016), but a small part may be diagenetic, formed as weathering products of feldspar and mica, and usually occurring as layers, lenses and films on the surface of macerals. illite and smectite are present as finely dispersed aggregates of irregular size and rarely as long platy crystals. clay minerals of epigenetic origin, which precipi­ tated in fractures, were also observed. feldspars are represented by plagioclase (albite; fig. 4a) and subordinate k­feldspar (orthoclase; fig. 4b). they are detrital in origin and are usually associated with clays. mica (biotite and muscovite; fig. 4c) is represented by platy or irregular shaped crystals, usually in association with feldspars in clay­rich layers. the mica is predominantly of detrital origin, but a small part might be a weathering product of feldspars. during the processes of coal formation mica is unstable and could transform to chlo­ rite, limonite, and clay minerals. chlorite (cr­rich chlorite as well, fig. 4d) was found in the i and ii seams. the majority of the chlorite in the kovin lignite is of detrital origin, formed as a weathering product of the crystalline basement rocks. detrital epidote, a calcium, aluminium and iron sorosilicate mineral (fig. 4e), occurs as individual crystals of irregular shapes. sulphates, anhydrite (caso4; fig. 4f) possibly gypsum as well, were determined in high amounts in several samples. in raw lignite, sulphate minerals are authigenic (mainly epigenetic) and/ or occur as weathering products. barite (baso4; fig. 4g) was de­ termined in very low amounts. the fe oxides and hydroxides (haematite and limonite) are present in considerable amounts in the kovin lignites. a large proportion of the fe­oxide/hydroxides in the kovin lignite samp­ les (fig. 4h) is probably the result of the weathering of iron­rich minerals such as pyrite and siderite. a small proportion of these minerals might also be of detrital origin. limonite (a mixture of goethite, lepidocrocite, and other fe­hydroxides) in the kovin table 3. xrd analysis of the kovine lignite ash. parameter i seam ii seam iii seam min-max x̅ s min-max x̅ s min-max x̅ s illite/smectite 12.05-46.66 26.51 11.11 14.79-73.55 38.92 15.64 11.68-30.77 19.01 7.17 quartz 3.97-52.61 26.91 14.92 8.62-57.19 24.05 13.05 6.03-69.30 43.36 23.57 anhydrite 13.10-52.28 28.53 13.07 3.16-54.64 22.33 17.06 0.59-47.67 18.38 17.83 plagioclase 0.67-10.96 5.39 3.02 0.49-11.99 5.51 3.44 1.68-17.21 10.85 4.99 hematite 4.37-17.13 8.57 3.97 0.25-19.59 6.82 6.70 0.13-5.73 2.91 2.15 calcite 0.01-25.30 5.14 7.47 0.39-20.33 4.50 5.36 0.07-28.38 6.18 9.66 x̅ – arithmetic mean value; min – minimum; max – maximum; s – standard deviation. note: values of parameters for individual samples are given in table s-iii of the supplementary material to this paper. table 4. mineral composition of the kovin lignite, based on data from sem-eds. mineral phases content i seam ii seam iii seam sulphides pyrite sphalerite galena m m m m m sulphate gypsum/anhydrite barite m m m m m oxides and hydroxides limonite hematite rutile ilmenite mn-fe oxides mn hydroxides m m m m m m m m m m m m m m silicates quartz opal/chalcedony illite smectite mica (biotite, muscovite) chlorite plagioclase (albite) k-feldspar (orthoclase) epidote allanite (orhite) zircon m m m m m m m m m m m m m m m m m m m m m m m carbonates calcite siderite dolomite ankerite m m m m m m phosphate monazite m m m–major mineral (>1 vol.%); m–minor mineral (<1 vol.%) g eo lo gi a c ro at ic a geologia croatica 72/158 figure 4. sem backscatter images with eds data of minerals; a) albite; b) k-feldspar; c) muscovite; d) cr-rich chlorite; e) epidote; f ) gypsum/anhydrite; g) barite; h) fe oxide/hydroxide. g eologia c roatica životić et al.: distribution of major and trace elements in the kovin lignite (serbia) 59 figure 4. continued; i) rutile in quartz; j) ilmenite; k-m) pyrite; n) sphalerite in quartz; o) ce, la allanite, p) monazite. g eo lo gi a c ro at ic a geologia croatica 72/160 lignite occurs mainly as collomorphous crusts built up of small flakes and usually appears in association with haematite and other minerals including siderite and clays. the fe­mn oxides and mn hydroxides were also detected in small amounts in coal seams i and ii. the ti and ti­fe oxides (rutile and ilmenite; fig. 4i, j) oc­ cur as small aggregates in low amounts in all seams. one of the most abundant carbonate minerals in the kovin lignite is calcite, whereas the other carbonates such as siderite, dolomite and ankerite are present in small amounts. calcite was determined in significant amounts in the central part of seams ii and iii (table 4), as well as in the lower bench of seam i in field a. carbonates occur as individual rounded and angular grains and spherical aggregates which implies most probably their syn­ genetic origin. siderite was observed in small amounts in seam ii and occurs as fine­grained lenses, layers and crusts, which are intimately associated with organic matter, suggesting most pro­ bably a syngenetic origin. dolomite occurs as small angular grains in low amounts in the central part of seam ii in field b. pyrite is one of the most abundant sulphide minerals and a typical authigenic mineral in the kovin lignite (fig. 4k, l, m). syn­ genetic pyrite occurs as framboidal and euhedral crystals (chou, 2012), situated along stratified bands or infilling cavities within the organic matter and cell openings of plant debris. crystals were formed within the lumens of densinite and textinite. very small amounts of epigenetic pyrite were determined. sphalerite and ga­ lena were detected in small amounts in seam ii (fig. 4n). table 5. contents of the major elements in the kovin lignite. element i seam ii seam iii seam clarke value of brown coalsa, ppmmin-max x̅ s x̅ g min-max x̅ s x̅ g min-max x̅ s x̅ g major elements, % si 0.88–11.87 6.40 3.45 5.26 0.40–17.33 7.50 5.31 5.40 0.34–21.84 9.68 7.92 4.88 al 0.52–5.15 2.48 1.36 2.11 0.20–5.72 2.90 1.61 2.31 0.26–4.37 2.39 1.33 1.38 – si/al 1.67–6.17 2.66 1.16 2.19 2.06–5.12 3.03 1.14 2.88 1.28–5.34 3.39 1.54 2.45 fe 0.59–9.01 2.88 1.92 2.45 0.36–5.03 2.38 1.11 2.08 0.80–3.70 1.91 1.05 1.56 – ti 0.02–0.18 0.10 0.05 0.09 0.01–0.32 0.13 0.10 0.10 0.01–0.29 0.14 0.09 0.08 720±40 ca 1.14–3.19 1.88 0.52 1.81 0.17–2.15 1.36 0.42 1.25 0.98–2.10 1.67 0.42 1.09 – mg 0.25–0.67 0.43 0.12 0.41 0.04–0.59 0.38 0.13 0.34 0.33–0.48 0.40 0.05 0.24 – na 0.04–0.33 0.14 0.08 0.12 0.01–0.36 0.11 0.08 0.08 0.11–0.64 0.34 0.22 0.27 – k 0.04–0.44 0.16 0.11 0.13 0.01–0.31 0.17 0.09 0.14 0.02–0.55 0.28 0.20 0.16 – mn 0.01–0.15 0.03 0.04 0.02 0.001–0.04 0.02 0.01 0.01 0.01–0.03 0.02 0.01 0.01 100±6 table 6. trace element content of the kovin lignite. element i seam ii seam iii seam clarke value of brown coala, ppmmin-max x̅ s x̅ g min-max x̅ s x̅ g min-max x̅ s x̅ g as 4.00-140.00 30.86 33.04 21.53 4.30-70.40 26.68 17.89 20.17 4.50-21.20 12.76 5.53 11.59 7.6±1.3 ba 40.88-173.15 90.41 38.23 83.44 9.27-170.27 90.24 41.54 77.50 61.2-239.83 148.11 72.86 131.03 150±20 cd 0.58-6.45 2.04 1.39 1.74 0.20-3.19 1.69 0.72 1.48 0.72-2.32 1.40 0.55 1.30 0.24±0.04 co 3.40-35.80 12.95 8.46 10.94 2.50-34.30 13.90 9.63 11.04 1.50-25.10 13.19 8.25 9.72 4.2±0.3 cr 35.24-371.41 111.65 87.50 88.93 8.38-226.73 96.89 57.31 78.59 11.86-265.33 123.58 97.57 84.04 15±1 cu 3.53-72.54 31.95 21.03 23.38 3.14-77.21 39.03 23.49 30.13 3.79-62.41 35.64 22.01 25.95 15±1 ga 2.10-16.30 8.85 4.38 7.58 0.90-25.60 11.26 7.39 8.56 1.00-16.50 8.12 5.02 6.34 5.5±0.3 li 3.82-54.11 23.09 14.68 18.47 2.21-85.06 37.95 27.01 27.50 1.75-37.88 20.38 11.33 15.17 10±1 mo 1.10-11.50 6.00 2.82 5.25 0.70-9.80 5.16 2.26 4.49 1.90-8.90 4.72 2.08 4.32 2.2±0.2 ni 13.70-214.00 61.79 53.68 47.47 9.40-206.10 71.18 50.76 54.11 9.70-77.50 45.64 24.78 37.79 9.0±0.9 pb 6.88-175.67 68.55 45.63 51.85 4.06-179.87 63.82 45.08 47.18 2.84-82.10 43.49 24.31 31.77 6.6±0.4 rb 0.39-36.06 9.67 9.16 6.40 0.79-32.97 9.99 8.01 7.05 0.84-36.25 15.76 10.80 11.10 10±0.9 sb <0.5 <0.5 <0.5 0.84±0.09 sc 1.24-11.24 6.01 3.08 5.13 0.64-15.06 7.18 4.34 5.70 0.62-8.14 4.98 2.19 4.20 4.1±0.2 se 1.30-9.00 3.02 1.96 2.62 0.30-4.90 2.25 0.99 2.00 0.90-4.30 2.41 1.17 2.15 1.0±0.15 sr 46.04-253.06 100.78 54.12 90.59 10.19-176.12 88.80 33.85 79.91 120.71-218.89 184.17 30.71 181.58 120±10 th 0.10-3.70 1.37 1.03 0.92 0.10-2.60 1.32 0.76 0.97 1.40-2.90 2.17 0.56 2.11 3.3±0.2 tl <0.5 <0.5 <0.5 0.68±0.07 v 7.60-76.82 41.56 19.32 35.89 6.46-110.76 53.03 29.93 43.18 3.31-54.51 33.18 15.88 26.89 22±2 zn 11.18-174.79 49.72 43.24 37.18 3.95-239.66 69.75 60.79 48.58 4.30-62.52 31.22 18.72 24.21 18±1 g eologia c roatica životić et al.: distribution of major and trace elements in the kovin lignite (serbia) 61 rare grains of rey­rich phosphates, monazite (fig. 4o) of irregular shape were detected in coal seams ii and iii. ce, la al­ lanite (calcium, aluminium, iron sorosilicate mineral; fig. 4p), probably of detrital origin, occur as individual small crystals of irregular shapes in coal seam i. 4.4. geochemistry variations of the si, al, ti and k contents in the studied samples are obvious in each seam and mostly depend on coal lithotypes (table 5; table s­iv of the supplementary material to this paper; figs. 2, 3). it is obvious that the mineral­rich and mixture of ma­ trix and mineral­rich coal have high contents of the aforemen­ tioned major elements. the average si contents in the kovin lig­ nites are 6.40%, 7.50% and 9.68% for coal seams i, ii and iii, respectively, while the respective al contents are 2.48%, 2.90% and 2.39%. a high si/al ratio in all three seams (table 5) implies high contents of quartz, illite/smectite and plagioclase. the lignite from the kovin deposit is enriched in as, cd, co, cr, cu, ga, li, mn, mo, ni, pb, v, zn, gd, tb, er and lu in com­ parison with clarke values for brown coals (ketris & yudo­ vich, 2009). the lignite in seam i is particularly enriched in as (4.00–140.00 mg/kg), cr (35.24–371.41 mg/kg), ni (13.70–214.00 mg/kg), pb (6.88–175.76 mg/kg) and zn (11.18–174.79 mg/kg), (table 6; table s­v of the supplementary material to this paper; figs. 5, 6). the bottom part of seam i in field b (sample 31/91) with high ash (52.56%, dry basis; fig. 6) and the highest total sul­ phur content (4.40%, dry basis), si/al ratio (6.17), fe (9.01%, dry basis) and mn (0.15%, dry basis) content has the highest content of all mentioned elements except pb and zn (table s­v of the supplementary material to this paper). the coal in seam ii is es­ pecially enriched in as (4.30–70.40 mg/kg), cr (8.38–226.73 mg/ kg), li (2.21–85.06 mg/kg), ni (9.40–206.10 mg/kg), pb (4.06– 179.87 mg/kg), v (6.36–110.76 mg/kg) and zn (3.95–239.66 mg/ kg). coal from seam iii is enriched in ba (61.23–239.83 mg/kg), cr (11.86–265.33 mg/kg) and sr (120.71–218.89 mg/kg). there are several geochemical and economic classifications of rare earth elements and yttrium (rey; seredin, 2010; se­ redin & dai, 2012). the three­fold geochemical classification, which divides rey into light (lrey – la, ce, pr, nd, and sm), medium (mrey – eu, gd, tb, dy, and y), and heavy (hrey – ho, er, tm, yb, and lu) groups according to seredin & dai (2012) is more convenient for the description of rey distribution in coals and conventional rey ores. the content of lrey, mrey and hrey in the kovin lignite is generally low in all seams (table 7; table s­vi of the supplementary material to this paper) with a predominance of lrey in all three seams. the ave­ rage lrey contents in lignite are 31.15 mg/kg, 25.71 mg/kg and 34.02 mg/kg for seams i, ii and iii respectively. the gd, tb, er and lu contents are higher than the clarke values for brown coals (ketris & yudovich, 2009), based on calculation of ave­ rage individual lanthanides and y. 5. discussion the mineral matter in coal seams and deposits depends on the combination of specific plant constituents influenced by water level, regional depositional and paleo­environmental factors, which control the enrichment or depletion of the different ele­ ments and mineral phases contained in the coal. chemical, bio­ logical and physical factors in mire systems provide specific en­ vironments in which minerals could be deposited or formed table 7. rare earth element content in the kovin lignite. element i seam ii seam iii seam clarke value of brown coala, ppmmin-max x̅ s x̅ g min-max x̅ s x̅ g min-max x̅ s x̅ g la 3.56–12.86 7.25 3.00 6.66 0.81–10.77 5.70 2.7 4.95 1.90–15.21 8.05 4.02 6.92 10±0.5 ce 5.00–28.70 13.24 6.34 11.89 1.70–17.80 10.79 4.41 9.59 2.70–21.40 13.92 6.35 11.93 22±1 pr 1.80–5.90 3.42 1.31 3.19 0.40–5.40 2.97 1.32 2.59 1.40–7.10 4.36 1.74 3.96 3.5±0.3 nd 2.90–10.20 6.15 2.35 5.71 0.80–9.90 5.23 2.43 4.53 1.70–10.80 6.81 2.82 6.06 11±1 sm 0.15–2.20 1.08 0.61 0.86 0.10–1.70 1.02 0.44 0.88 0.10–1.60 0.89 0.48 0.71 1.9±0.1 eu 0.23–1.59 0.63 0.35 0.55 0.08–0.83 0.52 0.19 0.47 0.15–0.84 0.55 0.22 0.49 0.5±0.02 gd 3.53–11.18 7.39 2.57 6.93 0.76–15.70 8.05 4.07 6.78 2.48–14.57 8.61 4.10 7.53 2.6±0.2 tb 0.20–2.10 0.97 0.53 0.82 0.10–4.50 1.72 1.11 1.29 0.50–3.10 1.39 1.09 1.07 0.32±0.03 dy 0.33–2.68 1.27 0.75 1.06 0.13–1.94 1.02 0.48 0.87 0.11–1.63 1.15 0.47 0.95 2.0±0.1 y 2.09–17.54 7.96 4.74 6.69 0.76–13.47 6.43 2.95 5.58 0.99–8.67 6.40 2.43 5.59 8.6±0.4 ho 0.04–1.35 0.51 0.34 0.39 0.06–0.80 0.49 0.21 0.41 0.05–0.93 0.54 0.30 0.42 0.50±0.05 er 0.40–2.45 1.22 0.67 1.05 0.14–1.92 1.03 0.38 0.93 0.21–1.23 0.98 0.34 0.88 0.85±0.08 tm 0.12–0.52 0.27 0.13 0.24 0.03–0.36 0.22 0.09 0.19 0.08–0.38 0.27 0.09 0.25 0.31±0.02 yb 0.31–2.71 1.26 0.72 1.07 0.14–2.00 1.13 0.45 1.00 0.15–1.38 0.99 0.40 0.86 1.0±0.05 lu 0.14–2.65 0.75 0.59 0.61 0.09–1.19 0.61 0.30 0.52 0.13–0.91 0.52 0.29 0.43 0.19±0.02 lreyb 14.01–51.15 31.15 12.55 28.64 3.81–43.60 25.71 10.70 22.79 7.80–55.31 34.02 14.86 29.79 mreyb 6.46–33.22 18.09 7.97 16.37 1.73–24.13 17.27 6.14 15.36 4.23–26.43 17.94 7.45 15.93 hreyb 1.16–9.45 4.01 2.31 3.42 0.46–5.95 3.46 1.31 3.10 0.61–4.66 3.30 1.33 2.89 σrey 22.17–87.75 53.25 21.91 48.72 6.0–69.96 46.45 16.07 42.03 12.64–82.63 55.26 22.76 48.87 a ketris & yudovich, 2009; b seredin & dai, 2012; lrey = la+ce + pr + nd + sm; mrey = eu + gd + tb + dy + y; hrey = ho + er + tm + yb + lu; min – minimum; max – maximum; x̅ – arithmetic mean value; s – standard deviation; x̅ g – geometric mean value. note: values of parameters for individual samples are given in table s-iii for major elements, s-iv for trace elements and s-v for rare earth elements and yttrium of the supplementary material to this paper. g eo lo gi a c ro at ic a geologia croatica 72/162 (gluskoter, 1975; taylor et al., 1998; ward, 2016). epi­ genetic factors may also influence the variation in elements (christanis et al., 1998; kalaitzidis et al., 2002; dai et al., 2012). the modes of mineral occurrences, their abundance and distribution in coal may characterize seams, deposits, and facies changes. it can be used as an indicator for the partial re­ construction of the environment conditions during peatification and coal formation (vassilev & vassileva, 1996, 1998). 5.1. affinity of the elements and geochemical associations high inorganic affinity (rash=0.7–1.0; table 8; eskanazy et al., 2010; kortenski & sotirov, 2002) is observed for al, si, ti, k, ba, cr, ga, pb, rb, sc, v, la, ce, nd, sm, eu, gd, ho, and yb in coal seam i with strong positive correlations with ash yield, as well as for al, si, ti, ba, cr, cu, ga, in, li, sc, se, v, gd and tb in seam ii, and for al, si, ti, fe, k, na, mn, ba, cd, cr, ga, ni, sc, th, zn, ce, sm, eu, gd, tb, ho, er, yb and lu in seam iii. the strong correlation between ash yield and si, al, k and na (table 8, table s­v of the supplementary material to this pa­ per) imply the predominance of aluminosilicate and silicate mine­ rals (fig. 4) in all three seams. as expected, the content of mine­ ral matter from maceral analyses shows a strong correlation with ash yield in all three seams. elements with a less but still rela­ tively high inorganic affinity (rash=0.5–0.69; table 8) include: fe, na, cd, co, li, mo, ni, se, th, tb, dy, y, er, tm, lu (in the seam i); fe, k, na, pb, th, sm, eu, ho, yb, lu (in the seam ii) and li, v, la, pr, nd, dy, y (in the seam iii). some elements, such as mg, mn, as, cu, zn and pb, in seam i; mo, zn, in seam ii; mg, co, cu, mo, pb, rb, se, in seam iii, have mixed affinities with figure 5. macropetrographic profiles of boreholes gd-601 (a) and gd-603 (b) in the a field lignite and the vertical distributions of ash, total sulphur content and some trace elements in coal. adb – ash content, dry basis, %; sdb – total sulphur content, dry basis, wt.%. g eologia c roatica životić et al.: distribution of major and trace elements in the kovin lignite (serbia) 63 correlation coefficients varying from 0.35 to 0.49 between ash yield and the aforementioned elements. sr in seam i; sdb and ca in seam ii, and ca, as and sr in seam iii show organic affinity (rash= –0.35 – –1.00; table 8). according to the geochemical and sem­eds data most trace elements have good correlation coefficients with al and si (table 6), indicating their close connection with silicate and alumino­ silicate minerals (quartz, plagioclase, albite, orthoclase, biotite, figure 6. macropetrographic profiles of boreholes kb-79 (a) and kb-91 (b) in the b field lignite and the vertical distributions of ash, total sulphur content and some trace elements in coal. adb – ash content, dry basis, %; sdb – total sulphur content, dry basis wt.%. g eo lo gi a c ro at ic a geologia croatica 72/164 and muscovite; fig. 4) as well as with illite/smectite and chlorite in all coal seams. this result confirms the clastic input in the pa­ laeomire during formation of all coal seams in the upper mio­ cene. pyrite is the most abundant sulphide mineral in the kovin lignite. a strong positive correlation between sulphur content (rs­ tot>0.7; table 8) and fe, as, cd, se, in seam i, as in seam ii, as well as a good correlation between sulphur content (rstot=0.5–0.69) and co, cr, mo, in seam i, mo in seam ii and sr in seam iii, im­ ply a close connection with pyrite. the result of sem­eds exa­ mination confirms the correlation data (fig. 4k, l, m). the mi­ neral­rich lignite in the bottom part of seam i of field b is particularly enriched in as (fig. 4). a very strong correlation between fe, as and cd and all of them with sdb in seam i, clearly indicates the same origin of these elements and a close connec­ tion with pyrite (dai et al., 2003; diehl et al., 2012; finkel­ man, 1994; yudovich & ketris, 2005a; 2012). cr, ni, pb and zn show good correlation with si and al (table 8) and a most probable connection with aluminosilicate minerals (illite/smec­ tite, chlorite; fig. 4d). the strong correlation of ca and sr in seam i shows that sr is associated with the carbonate minerals (calcite). 5.2. comparison between coal petrology and major and trace elements in coal the mineralogical compositions of the kovin lignites are quite similar, and quartz, illite/smectite, gypsum/anhydrite, plagio­ clase (albite), haematite, calcite and pyrite are the common mine­ rals for both coalfields. the determined minerals are rich in si, al, ti and k and they are compatible with the mineralogical com­ position of the lignite in both fields. also, the relatively high con­ tent of fe in the lignite can be related to the high pyrite and hae­ matite content, while the high ca content could be connected with high gypsum/anhydrite and calcite contents. to further evaluate the relationships between lithotypes, mineralogy and geochemistry, profiles representing the vertical variation in mineralogy were placed alongside profiles of the ma­ jor element proportions (si, al, fe, ca, mg, ti, k, na, mn) in the a field (fig. 2), and the b field (fig. 3). profiles representing the vertical variation of the most important trace elements (as, cd, cr, ni, pb, se) in the kovin lignite are presented in figs. 5 and 6 for fields a and b, respectively. the variations in lithotypes, maceral composition and ash contents (mitrović et al., 2016) indicate that the water level changed during peat accumulation. increased ash content (figs. 5 and 6) may indicate more frequent inundations of the precursor mire resulting in deposition of siliciclastics. 5.2.1. coal seam iii mineral rich and mixtures of matrix and mineral rich coals with a predominance of detrohuminite, relatively low sulphfur content and higher ash contents in the bottom part of the coal seam iii (samples 14/79–21/79; fig. 3) imply that peat accumulation de­ veloped in a freshwater environment of a higher water level of the mire. organic matter (om) mainly originates from herbs and shrubs along with aquatic species with a small contribution from conifers (mitrović et al., 2016). the high si and al content in most samples, as well as higher contents of k and na imply de­ position of siliciclastic minerals such as quartz with variable amounts of illite/smectite and plagioclase. the central part of the seam consists of mixtures of xylite and matrix and matrix and mineral rich coals with two thin xy­ table 8. element affinities deduced from calculation of pearson’s correlation coefficients between the concentration of each element in the coal and ash yield, total sulphur content, si and al. i seam ii seam iii seam positive correlation with ash yield rash=0.7–1.0 al, si, ti, k, ba, cr, ga, pb, rb, sc, v, la, ce, nd, sm, eu, gd, ho, yb, lrey, mrey, hrey. al, si, ti, ba, cr, cu, ga, li, sc, se,v, gd, tb. al, si, ti, fe ,k, na, mn, ba, cd, cr, ga, ni, sc, th, zn, ce, sm, eu, gd, tb, ho, er, yb, lu, lrey, mrey, hrey. rash=0.50–0.69 fe, na, cd, co, li, mo, ni, se, th, tb, dy, y, er, tm, lu. fe, k, na, pb, th, sm, eu, ho, yb, lu, hrey. li, v, la, pr, nd, dy, y. rash=0.35–0.49 sdb, mg, mn, as, cu, zn, pr. mo, zn. mg, co, cu, mo, pb, rb, se. negative correlation with ash yield rash= -0.34–0.34 ca. mg, mn, as, cd, co, ni, rb, sr, la, ce, pr, nd, dy, y, er, tm, lrey, mrey. tm. rash= -1.0– -0.35 sr. sdb, ca. ca, as, sr. positive correlation with total sulphur content rstot=0.7–1.0 fe, as, cd, se. as. rstot=0.5–0.69 mn, co, cr, mo. mo. sr. al affinity ral= 0.7–1.0 si, ti, cu, ga, li, sc, th, v, gd, tb. si, ti, k, ba, cr, cu, ga, li, pb, sc, th, v, sm, eu, gd, tb, ho, si, ti, fe, k, na, mn, ba, cd, cr, ga, li, ni, sc, th, v, zn, ce, pr, nd, sm, eu, gd, tb, dy, y, ho, er, yb, lu, lrey, mrey, hrey. ral = 0.5–0.69 mg, k, ba, pb, rb, sm, mrey. fe, na, mo, se,er, yb, lu, hrey. mg, co, cu, mo, pb, se, la. si affinity rsi= 0.7–1.0 al, ti, k, ba, cr, ga, li, pb, rb, sc, th, v, la, ce, nd, sm, gd, ho, lrey, mrey. ti, na, ba, cr, cu, ga, li, sc, se,v, gd, tb, ho. ti, fe, k, na, mn, ba, cd, cr, ga, ni, sc, th, ce, sm, eu, gd, tb, ho, er, yb, lu, mrey, hrey. rsi = 0.5–0.69 fe, na, co, ni, pr, eu, tb, dy, y, er, tm, yb, lu, hrey. fe, k, pb, th, sm, eu, yb, lu, hrey. li, v, la, pr, nd, dy, y, lrey. sdb – total sulphur content, dry basis wt.%; note: values of the correlation coefficients for individual elements are given in table s-vi of the supplementary material to this paper. g eologia c roatica životić et al.: distribution of major and trace elements in the kovin lignite (serbia) 65 lite­rich layers indicating an unstable water table from higher to lower water level in the mire and less wet conditions. a predomi­ nance of detrohuminite with lower ash content confirms decline of water level in the mire. high amounts of inertinite in these samples can be attributed in part to oxidation, but regarding the inertinite­detrohuminite maceral association an allochthonous origin is more probable (taylor et al., 1998; o’keefe et al., 2013). a slight increase in the sulphur (sdb) and ca content sug­ gests input of mineral matter by inflowing sulphate­rich freshwa­ ter with the formation of sulphate minerals (gypsum/anhydrite; fig. 4f) confirmed by mineralogical examination. two thin xy­ lite­rich coal samples (14/79 and 16/79) with a predominance of telohuminite suggest that deposition of the om started in a topo­ genous fresh water mire, which was transformed into a time lim­ ited wet forest swamp. the high content of carbonate and sulphate minerals with relatively high ca and total sulphur content (sdb) indicate the influence of neutral to alkaline groundwater. further­ more, a good negative correlation coefficient between ca and ash content (table 8; table s­vi of the supplementary material to this paper) indicates that ca may also be bound with organic matter as exchangeable ions in carboxylic acids and phenolic or hydroxyl groups (li et al., 2007, 2010; ward, 2016). also, its occurrence is possible in metalloporphyrins and other metal­organic com­ pounds (saxby, 2000) especially in low­rank coals. the top of coal seam iii (sample 11/79) consists of mixtures of matrix and mineral rich coals with the dominance of detro­ huminite. the high ash content as well as the si, al, k and na contents, associated with an si/al ratio of 5.00 (table s­iv of the supplementary material to this paper) indicates a higher water level in the mire with deposition of siliciclastic minerals such as quartz and subordinate clay minerals and plagioclase. coal from seam iii is enriched in ba, cr and sr (table 6). the high cr content was detected in mineral­rich lithotypes with high ash content (fig. 6). chromium could be present in coal as both organic and inorganic forms (ketris & yudovich, 2009). in most bituminous coals from the usa two major forms are present (huggins & huffman, 2004): organic associa­ tion and in illite. cr could be also present in oxide/carbonate/ monosulphide group, and in silicates (dale et al., 1999). coals enriched in cr (≥~100 ppm) are usually situated near to ultramafic rocks that contain chrome­bearing spinels (huggins et al., 2000; ruppert et al., 1996). in the studied coals, a strong cor­ relation of cr with ash content and si, al, ti, k and fe in seam iii suggests that the cr mainly occurs in aluminosilicate mine­ rals, most probably cr­rich chlorite (fig. 4d). the ultramafic rocks which outcrop in the southeastern part of the study area can be the source of cr in the studied lignite. furthermore, a high content of cr, ni and other elements detected in lignite from the drmno field (fig. 1; životić et al., 2015) suggests a similar source. the strong correlation of ba with ash content suggests an inorganic form probably as barite (fig. 4g), while sr indicates an organic form (table 8). the results of the chemical and mineralo­ gical investigation of the kovin lignite samples indicate an or­ ganic form of as in seam iii. 5.2.2. coal seam ii the geochemical composition of coal seam ii shows some diffe­ rences between fields a and b. organic matter of the lignites from both coalfields was derived from herbs and shrubs with variable amounts of woody vegetation (mitrović et al., 2016). matrix and mixtures of matrix and mineral rich coals with a slight pre­ dominance of detrohuminite over telohuminite built the bottom part of seam ii in field a (samples 48/601, 49/601, 55/603, 56/603; fig. 2). the coal is characterised by moderate to very high ash and a low to moderate sulphur content. the high si, al, k, and na contents suggest a high contribution from siliciclastic sedi­ ments. the upper part of seam ii in field a consists of xylite­rich coal (54/603), with moderate amounts of ash and sulphur. the si/al ratio is still high, as well as the amounts of ca and fe, sug­ gesting a greater contribution of siliciclastic sediments with vari­ able amounts of fe­oxide/hydroxides (fig. 4h). an outstanding negative correlation between ca and sulphur content (sdb), as well as with ash content (table 8) suggests the organic affinity of ca and s. according to previous research (chou, 2012; li et al., 2007, 2010; ward, 2016) in neutral to alkaline groundwater ca and s could be taken by peat forming plants in the palaeomire and bound with organic matter. xylite­rich and mixtures of xylite­rich and matrix coals with prevalence of telohuminite occur in the bottom part of coal seam ii in field b (samples 39­40/91, 8/79; fig. 3). lignite is characte­ rised by moderate ash and low to high sulphur contents with vari­ able si and al followed by higher ca and fe contents, suggesting a higher contribution of siliciclastic sediments with variable amounts of fe­oxide/hydroxides and sulphates. the central part of seam ii is characterised by moderate to high ash and a low/ moderate to high sulphur content with variable content of major elements. the higher ca and fe contents in xylite­rich samples (4/79, 37/79) suggest a higher contribution of sulphates and fe­ oxide/hydroxides formed in a neutral to alkaline and probably oxic environment. matrix and mixtures of matrix and xylite­rich coal with moderate contents of ash and sulphur built up the upper part of seam ii. higher contents of si and al in borehole kb­91 (samples 33/91, 34/91) indicate a higher contribution of siliciclastic sediments, while the higher contents of ca and total sulphur in borehole kb­79 (sample 2/79) may suggest a slight predominance of sulphate minerals and changes in water level and the paleoenvironment. the content of as, cr, ni, pb, v and zn in seam ii coal is several times higher in comparison with the clarke values for brown coal (ketris & yudovich, 2009). arsenic could be present in pyrite (dai et al., 2003; diehl et al., 2012; finkel­ man, 1994; kolker, 2012 yudovich & ketris, 2005a, and references therein) but also as the arsenate ion in clays or phosphate minerals (swaine, 1990). organic bound arsenic is also common, with higher contents in lower organisms, algae and herbages than in seed plants, ferns, and moss (liu et al., 2003). three dominant forms of as in coal (yudovich & ketris, 2005a, b) are pyritic, organic and arsenate. recent research on as rich coals from the xishanyao formation, china (zhang et al., 2018) confirms sulphfide bound, residual form, organic bound and adsorption solution of arsenic. the same authors conclude that the geological origins leading to the enrichment of arsenic in coal are: hydrothermal solution activities controlled by the tec­ tonic fracturing of the region, sources of terrigenous detrital ma­ terial controlled by regional geological settings with the distribu­ tion of elements and type of plants in the paleomire. the results of the chemical and mineralogical investigation of the kovin lig­ nite samples indicate a pyritic form of as in seam ii. a strong correlation of cr with si, al, ti and fe in seam ii, suggests that the cr mainly occurs in aluminosilicate minerals. nickel could be present in coal in organic and inorganic form. it can be asso­ ciated with clays (kaolinite, illite, smectite) and sulphides (pyrite, millerite, bravoite; yudovich & ketris, 2005b). organically bound ni is also common in coal (ruppert et al., 1996). nickel g eo lo gi a c ro at ic a geologia croatica 72/166 in seam ii of the kovin deposit shows no specific affinity, indi­ cating both organic and mineral associations. lead mainly occurs as sulphide (galena) or associated with sulphide minerals (fin­ kelman, 1994), as well as lead selenide in coals (hower & robertson, 2003). it could also be present in silicates (dale et al., 1999). kovin lignite in seam ii has a pb content that is seve­ ral times higher content than the clarke value for brown coals (ketris & yudovich, 2009). the positive correlations of pb with si, al, ti and k in all seams indicate the presence of pb in the clay minerals. 5.2.3. coal seam i lignite from seam i from the a field shows some differences be­ tween the lower (ib) and upper (ia) layers. the lower part of the ib layer (samples 44/601­46/601 and 51/603­53/603), made of a mixture of matrix and xylite­rich coal, has variable amounts of si and al, with high contents of ca, fe and mn in samples 45/601 and 52/603, followed by a higher si/al ratio. the lignite from the ib layer is characterised by moderate to high ash and sulphur con­ tents, while the upper (ia) layer is characterised by moderate ash and sulphur contents and variable amounts of ca and fe with a higher si/al ratio, which is compatible with a higher contribution of siliciclastic sediments. the characteristics of lignite in seam i of the b field (samples 26/91­31/91) revealed that mineral matter in the matrix coal con­ sists of siliciclastic sediments, while xylite­rich coal has higher ca, fe and mn contents. the lignite is characterised by moderate to high ash and sulphur contents indicating an unstable water ta­ ble with frequent flooding. the highest sulphur (4.40%; table s­ii of the supplementary material to this paper) and ash contents are identified in the lowermost, mineral rich sample (31/79; fig. 4b), which is also enriched in fe (fig. 7b). the good correlation be­ tween sulphur and fe contents (table 8) is commensurate with pyrite as the main source of both elements (fe, sdb) in seam i. that part of seam i is especially enriched in as, cd, cr, ni, pb and se with the highest value of as (140.0 mg/kg), cd (6.5 mg/ kg), cr (371.4 mg/kg), ni (214.0 mg/kg) and se (9.0 mg/kg). in comparison with the clarke value for brown coal (ketris & yudovich, 2009) these values are 18, 27, 25, 24 and 9 times higher for as, cd, cr, ni, pb and se respectively. a very strong correlation as–sdb (table 6) indicates a pyritic form of as in coal seam i. cadmium is predominantly associated with zn mostly in sphalerite (zns; goodarzi, 2002), as well as in other sulphides (e.g. pyrite; dale et al., 1999). however, an ”organic” form of cd is also possible (yudovich et al., 1985). the very strong correlation of cd–sdb (table 8), cd–fe (r=0.97) clearly indicates the close connection of cd with pyrite in seam i. selenium could be present in organic and inorganic form (yudovich & ket­ ris, 2005b, 2006). in high sulphur coals, se is concentrated in sulphide minerals (pyrite) and some selenitic forms (clausthalite, pbse). in oxidized coals, se is enriched in the bed oxidation zones (yudovich & ketris, 2006), with u, fe, mo, v, and pb. the strong correlation of se with sdb (r=0.76) supports their occur­ rences in pyrite. the results of the chemical and mineralogical investigation of the kovin lignite samples indicate a pyritic form of as, cd, co, cr, mo, se in seam i (table 8; fig. 4k, l, m) formed in pre­ sumably neutral and anaerobic conditions in the palaeomire. the very strong correlation of fe with as (r=0.94), cd (r=0.97), co (r=0.82), cr (r=0.91), ni (r=0.87), se (r=0.91), and as with cd (r=0.96), co (r=0.79), cr (r=0.79), ni (r=0.81), se (r=0.93) con­ firms the close interrelation of the aforementioned elements with pyrite. the distribution and enrichment of elements was presu­ mably controlled by conditions during peat accumulation. a higher water level in a palaeomire with increases in clastic inputs resulted in high concentrations of aluminosilicate minerals. sur­ face­ and groundwater from the surrounding palaeo­environ­ ment, rich in elements such as as, cd, co, cr, ni, se, derived from the weathering and leaching of the basement rocks, along with a reducing environment in the palaeomire, may have re­ sulted in the formation of syngenetic pyrite enriched in some ele­ ments, as as, se, and sb may be substituted with s in the pyrite structure (kolker, 2012). 6. conclusion the upper miocene kovin sedimentary sequence consists of shallow, caspi­brackish to fresh water clastic sediments (sand and silt with thin clay, carbonaceous clay and gravel layers), with three lignite seams, iii, ii and i (from lowest to highest). huminite is the prevailing maceral group in the three coal seams. the most abundant maceral subgroups are telohuminite and detrohuminite with variable amounts of gelohuminite. lipti­ nite and inertinite are much less abundant. the content of mineral matter varies between 3 and 37 vol. %. clays are the most abun­ dant, while pyrite, carbonates and other minerals are less abun­ dant. sem­eds examination revealed that the most abundant minerals in all the studied lignite samples from all coal seams are clays (illite/smectite), silicates (quartz, plagioclase), sulphate (gypsum/anhydrite) and carbonate (calcite). the other iron­rich minerals are sulphides, oxides and hydroxides (pyrite, magnetite, haematite, and limonite). minor minerals such as rutile, ilmenite, k­feldspar (albite, orthoclase), and mica, were detected in all coal seams. in addition, barite, chlorite, epidote, allanite and zircon were also detected in coal seam i. sphalerite, galena, siderite, do­ lomite, ankerite and monazite were identified in coal seam ii, while barite and monazite were found in coal seam iii. according to the mineralogical and geochemical data, sili­ cate and aluminosilicate minerals (quartz, plagioclase, albite, or­ thoclase, biotite, and muscovite) together with illite/smectite and chlorite are the main carriers of si, al, na and k in all coal seams. the lignite from the kovin deposit is enriched in as, cd, co, cr, cu, ga, li, mn, mo, ni, pb, v, zn, gd, tb, er and lu in com­ parison with the clarke values for brown coals. almost all of these elements demonstrate a strong inorganic affinity, but some of them (as, ca, s, sr) also have an outstanding organic affinity. a group of elements in seam ii are both inorganically and organ­ ically bound. the results of the correlation analysis indicate a pyritic form of as and cd in seam i, and an organic form in seam iii. cr, pb and se occur in aluminosilicate minerals in all three coal seams. ni is associated with sulphides in coal seam i, aluminosilicates in coal seam iii, whereas no specific affinity is observed for this element in coal seam ii. despite the high concentrations, zn does not show specific affinity in all coal seams. acknowledgement this work was financed by the ministry of education and sci­ ence of the republic of serbia (projects no. oi176006, oi176016 and oi172035), which is gratefully acknowledged. we are also grateful to the anonymous reviewers whose helpful suggestions and comments greatly benefited this paper. g eologia c roatica životić et al.: distribution of major and trace elements in the kovin lignite (serbia) 67 references basic geological map of serbia: http://geoliss.mre.gov.rs/ogk/rastersr­ bija (last accessed june 4, 2018). chatziapostolou, a., kalaitzidis, s., papazisimou, s., christanis, k., & vagias, d. (2006): mode of occurrence of trace elements in the pellana lignite (se peloponnese, greece).– international journal of coal geology, 65, 3–16. doi: 10.1016/j.coal.2005.04.005 chou, c.l. (2012): sulfur in coals: a review of geochemistry and origins.– interna­ tional journal of coal geology, 100, 1–13. doi: 10.1016/j.coal.2012.05.009 christanis, k., georgakopoulos, a., fernández­turiel, j.l. & bouz­ inos, a. (1998): geological factors influencing the concentration of trace ele­ ments in the philippi peatland, eastern macedonia, greece.– international journal of coal geology, 36, 295–313. dai, s., hou, x., ren, d. & tang, y. (2003): surface analysis of pyrite in the no. 9 coal seam, wuda coalfield, inner mongolia, china, using high­resolution time­of­ flight secondary ion mass­spectrometry.– international journal of coal geology, 55, 139–150. doi: 10.1016/s0166­5162(03)00109­5 dai, s., ren, d., chou, c.­l., finkelman, r.b., seredin, v.v. & zhou, y. (2012): geochemistry of trace elements in chinese coals: a review of abundances, genetic types, impacts on human health, and industrial utilization.– international journal of coal geology, 94, 3–21. doi: 10.1016/j.coal.2011.02.003 dale, l.s., chapman, j.f., buchanan, s.j. & lavrencic, s.a. (1999): me­ chanisms for trace element partitioning in australian coals – project 4.2 – final report, co­operative research centre for black coal utilisation. davidson, r.m. (2000): modes of occurrence of trace elements in coal; results from an international collaborative program.– iea coal research, london. diehl, s.f., goldhaber, m.b., koenig, a.e., lowers, h.a. & ruppert, l.f. (2012): distribution of arsenic, selenium, and other trace elements in high pyrite appalachian coals: evidence for multiple episodes of pyrite formation.– interna­ tional journal of coal geology, 94, 238–249. doi: 10.1016/j.coal.2012.01.015 electric power system of serbia (eps, 2018) ­ http://www.eps.rs (last ac­ cessed june 4, 2018). ercegovac, m., životić, d. & kostić, a. (2006): genetic–industrial classifica­ tion of brown coals in serbia.– international journal of coal geology, 68, 39–56. eskanazy, g.m., finkelman, r.b. & chattarjee, s. (2010): some conside­ rations concerning the use of correlation coefficients and cluster analysis in inter­ preting coal geochemistry data.– international journal of coal geology, 83, 491– 493. doi: 10.1016/j.coal.2010.05.006 filippidis, a., georgakopoulos, a., kassoli­furnaraki, a., misae­ lidis, p., yiakkoupis, p. & broussoulis, j. (1996): trace elements con­ tents in composited samples of three lignite seams from the central part of the drama lignite deposit, macedonia, greece.– international journal of coal geo­ logy, 29, 219–234. doi: 10.1016/0166­5162(95)00032­1 finkelman, r.b. (1994): modes of occurrence of potentially hazardous elements in coal: levels of confidence.– fuel procesing technology, 39, 21–34. doi: 10.1016/ 0378­3820(94)90169­4 finkelman, r.b., orem, w., cstranova, v., tatu, c.a., belkin, h.e., zheng, b., lerch, h.e., maharaj, s.v. & bates, a.l. (2002): health im­ pacts of coal and coal use: possible solutions.– international journal of coal geo­ logy, 50, 425– 443. doi: 10.1016/s0166­5162(02)00125­8 finkelman, r.b., palmer, c.a. & wang, p. (2018): quantification of the modes of occurrence of 42 elements in coal.– international journal of coal geology, 185, 138–160. doi: 10.1016/j.coal.2017.09.005 foscolos, a.e., goodarzi, f., koukouzas, c.n. & hatziyiannis, g. (1998): assessment of environmental impact of coal exploration and exploitation in the drama basin, northeastern greek­makedonia.– energy sources, 20, 795– 820. gentzis, t., goodarzi, f., koukouzas, c. & foscolos, a. (1996): petrolo­ gy, mineralogy, and geochemistry of lignites from crete, greece.– international journal of coal geology, 30, 131–150. doi: 10.1016/0166­5162(95)00034­8 gentzis, t., goodarzi, f. & foscolos, a.e. (1997): geochemistry and minera­ logy of greek lignites from ioannina basin.– energy sources, 19, 111–128. doi: 10.1080/00908319708908837 georgakopoulos, a. (2001): trace elements in the lava xylite/lignite deposit, servia basin, northern greece.– energy sources, 23, 143–156. doi: 10.1080/ 00908310151092335 gluskoter, h. (1975): mineral matter and trace elements in coal.– in: babu, s. (ed.): trace elements in fuel. am. chem. soc., washington, 1–22. doi: 10.1021/ ba­1975­0141.ch001 goodarzi, f. (2002): mineralogy, elemental composition and modes of occurrence of elements in canadian feed­coals.– fuel, 81, 1199–1213. doi: 10.1016/s0016­ 2361(02)00023­6 gürdal, g. (2011): abundances and modes of occurrence of trace elements in the çan coals (miocene), çanakkale­turkey.– international journal of coal geology, 87, 157–173. hower, j.c. & robertson, j.d. (2003): clausthalite in coal.– international journal of coal geology, 53, 219–225. doi: 10.1016/s0166­5162(03)00022­3 huggins, f.e. & huffman, g.p. (2004): how do lithophile elements occur in or­ ganic association in bituminous coals?– international journal of coal geology, 58, 193–204. doi: 10.1016/jcoal.2003.10.009 huggins, f.e., shah, n., huffman, g.p., kolker, a., crowley, s., pal­ mer, c.a. & finkelman, r.b. (2000): mode of occurrence of chromium in four us coals.– fuel processing technology, 63, 79–92. doi: 10.1016/j.coal.2003. 10.009 international committee for coal petrology (iccp), (2001): the new inertinite classification (iccp system 1994).– fuel, 80, 459–471. international committee for coal petrology (iccp), (1993): http:// www.iccop.org/documents/1993­iccp­international­handbook­of­coal­petrogra­ phy­3rd­suppl­to­2nd­ed­pdf.pdf (last accessed june 4, 2018). international standard organization (iso) 1171 (1997): methods for analysis and testing of coal and coke. determination of ash content.– internation­ al organization for standardization, switzerland (10 p). international standard organization (iso) 7404–2 (2009): methods for the petrographic analysis of coals–part 2: methods of preparing coal sam­ ples.– international organization for standardization, geneva, switzerland (12 p). iso 7404­3 (2009): methods for the petrographic analysis of coals – part 3: method of determining maceral group composition.– organization for standardization, swit­ zerland (7 p). kalaitzidis, s., christanis, k., georgakopoulos, a., fernández­tu­ riel, j.l. & papazisimou, s. (2002): influence of geological conditions dur­ ing peat accumulation on trace element affinities and their behavior during peat combustion.– energy fuel, 16, 1476–1482. doi: 10.1021/ef0200673 karayigit, a.i. & gayer, r.a. (2000): trace elements in a pliocene–pleistocene lignite profile from the afşin–elbistan field, eastern turkey.– energy sources, 22/1, 13–21. karayigit, a.i., gayer, r.a., querol, x. & onacak, t. (2000): contents of major and trace elements in feed coals from turkish coal fired power plants.– in­ ternational journal of coal geology, 44, 169–184. doi: 10.1016/s0166­5162(00) 00009­4 karayigit, a.i., gayer, r.a., ortac, e.f. & goldsmith, s. (2001): trace ele­ ments in the lower pliocene fossiliferous kangal lignites, sivas, turkey.– interna­ tional journal of coal geology, 47/2, 73–89. doi: 10.1016/s0166­5162(01)00030­1 ketris, m.p. & yudovich, ya.e. (2009): estimations of clarkes for carbonaceous biolithes:world averages for trace element contents in black shales and coals.– in­ ternational journal of coal geology, 78, 135–148. kolker, a. (2012): minor element distribution in iron disulfides in coal: a geochemi­ cal review.– international journal of coal geology, 94, 32–43. doi: 10.1016/j. coal.2011.10.011 kortenski, j. & sotirov, a. (2002): trace and major element content and distri­ bution in neogene lignite from the sofia basin, bulgaria.– international journal of coal geology, 52, 63–82. doi: 10.1016/s0166­5162(02)00133­7 kostova, i. & zdravkov, a. (2007): organic petrology, mineralogy and deposi­ tional environment of the kipra lignite seam, maritza­west basin, bulgaria.– in­ ternational journal of coal geology, 71, 527–541. doi: 10.1016/j.coal.2006.06.006 kovin mine – official web site: http://www.rudnikkovin.rs/wp (last accessed june 4, 2018). koukouzas, n., ward, c. & li, z. (2010): mineralogy of lignites and associated strata in the mavropigi field of the ptolemais basin, northern greece.– interna­ tional journal of coal geology, 81, 182–190. doi: 10.1016/j.coal.2009.12.012 li, z., ward, c.r. & gurba, l.w. (2007): occurrence of non­mineral inorganic ele­ ments in low­rank coal macerals as shown by electron microprobe element map­ ping techniques.– international journal of coal geology, 70, 137–149. doi: 10. 1016/j.coal.2006.04.009 li, z., ward, c.r. & gurba, l.w. (2010): occurrence of non­mineral inorganic ele­ ments in macerals of low­rank coals.– international journal of coal geology, 81, 242–250. doi: 10.1016/j.coal.2009.02.004 liu, g.j., yang, p., peng, z. & wang, g. (2003): geochemistry of trace elements from the no.3 coal seam of shanxi formation in the yanzhou mining district.– ge­ ochimica, 32, 55–62. magyar, i., geary, d.h. & müller, p. (1999): paleogeographic evolution of the late miocene lake pannon in central europe.– palaeogeography, palaeoclimato­ logy, palaeoecology, 147, 151–167. doi: 10.1016/s0031­0182(98)00155­2 magyar, i., radivojević, d., sztanó, o., synak, r., ujszászi, k. & póc­ sik, m. (2013): progradation of the paleo­danube shelf margin across the pan­ nonian basin during the late miocene and early pliocene.– global planetary change, 103, 168–173. doi: 10.1016/j.gloplacha.2012.06.007 meij, r. (1995): the distribution of trace elements during the combustion of coal.– in: swaine, d.j. & goodarzi, f. (eds.): environmental aspects of trace ele­ ments in coal.– kluwer academic publication, dordrecht, the netherlands, 111– 127. doi: 10.1007/978­94­015­8496­8_7 g eo lo gi a c ro at ic a geologia croatica 72/168 milivojević, j. & životić, d. (2006): genesis of coal from the kovin deposit based on the palynological and petrographic composition.– the 7th european paleobotanical and palynological conference, september 6–11, prague, czech republic, abstracts, 94 (isbn 80­7036­200­6). mitrović, d., đoković, n., životić, d., bechtel, a., šajnović, a. & stojanović, k. (2016): petrographical and organic geochemical study of the kovin lignite deposit, serbia.– international journal of coal geology, 168, 80–107. doi: 10.1016/j.coal.2016.07.008 mitrović, d., đoković, n., životić, d., bechtel, a., cvetković, o. & stojanović, k. (2017): characterization of lignite lithotypes from the “kovin” deposit (serbia) – implications from petrographic, biomarker and isotopic analy­ sis.– journal of the serbian chemical society, 82, 739–754. o’keefe, j.m.k., bechtel, a., christanis, k., dai, s., di michele, w.a., eble, c.f., esterle, j.s., mastalerz, m., raymond, a.l., valentim, b.v., wagner, n.j., ward, c.r. & hower, j.c. (2013): on the fundamental difference between coal rank and coal type.– international journal of coal geo­ logy, 118, 58–87. doi: 10.1016/j.coal.2013.08.007 palmer, c.a., tuncali, e., dennen, k.o., coburn, t.c. & finkelman, r.b. (2004): characterization of turkish coals: a nationwide perspective.– inter­ national journal of coal geology, 60, 85–115. doi: 10.1016/j.coal.2004.05.001 pavlović, m. (1959): contribution for stratigraphy of neogene sediments in the ko­ vin­gaj and ovča (banat) area.– annales géologiques de la péninsule balkanique, 26, 141–149 (in serbian with german abstract). pickel, w., kus, j., flores, d., kalaitzidis, s., christanis, k., cardott, b.j., misz­kennan, m., rodrigues, s., hentschel, a., hamor­vi­ do, m., crosdale, p. & wagner, n. (2017): classification of liptinite – ic­ cp system 1994.– international journal of coal geology, 169, 40–61. doi: 10.1016/j.coal.2016.11.004 querol, x., whateley, m.k.g., fernández­turiel, j.l. & tuncali, e. (1997): geological controls on the mineralogy and geochemistry of the beypazari lignite, central anatolia, turkey.– international journal of coal geology, 33/3, 255–271. doi: 10.1016/s0166­5162(96)00044­4 rietveld, h.m. (1969): a profile refinement method for nuclear and magnetic struc­ tures.– journal of applied crystallography, 2, 65–71. doi: 10.1107/ s0021889869006558 rodríguez­carvajal, j. (1993): fullprof suite: crystallographic tools for riet­ veld, profile matching & integrated intensity refinements of x­ray and/or neutron data. http://www.ill.eu/sites/fullprof/. rögl, f. (1996): stratigraphic correlation of the paratethys oligocene and miocene. mitteilungen der gesellschaft der geologie und bergbaustudenten in wien, 41, 65–73. ruppert, l., finkelman, r., boti, e., milosavljević m., tewalt, s., si­ mon, n. & dulong, f. (1996): origin and significance of high nickel and chro­ mium concentrations in pliocene lignite of the kosovo basin, serbia.– interna­ tional journal of coal geology, 29, 235–258. doi: 10.1016/0166­5162(95)00031­3 saxby, j.d. (2000): minerals in coal.– in: glikson, m. & mastalerz, m. (eds.): organic matter and mineralisation: thermal alteration, hydrocarbon generation, and role in metallogenesis. kluwer academic, dordrecht, 314–328.doi: 10.1007/ 978­94­015­9474­5_15 seredin, v.v. (2010): a new method for primary evaluation of the outlook for rare earth element ores.– geology of ore deposits, 52, 428–433. doi: 10.1134/ s1075701510050077 seredin, v.v. & dai, s. (2012): coal deposits as a potential alternative source for lanthanides and yttrium.– international journal of coal geology, 94, 67–93. doi: 10.1016/j.coal.2011.11.001 spajić­miletić, o. (1960): overview of the sarmatian and pannonian ostracod fau­ na in the mlava basin and sopotska greda.– annales géologiques de la péninsule balkanique, 27, 253–264 (in serbian with german abstract). spajić­miletić, o. (1969): biostratigraphy of the upper miocene.– annales géolo­ giques de la péninsule balkanique, 34, 11–19 (in serbian with german abstract). srps b.h8.317:1988, (1988): methods of analysis of coal and coke ­ determination of volatile matter content.– institute for standardization of serbia, belgrade, serbia, 6 p. (in serbian). srps b.h8.318:1972, (1972): methods of analysis of coal and coke ­ determination of gross calorific value by the calorimetric bomb method, and calculation of net calo­ rific value.– institute for standardization of serbia, belgrade, serbia, 11 p. (in ser­ bian). srps b.h8.338:1986, (1986): coal and coke ­ determination of total moisture content ­ gravimetric method.– institute for standardization of serbia, belgrade, serbia, 5 p. (in serbian). srps b.h8.390:1987, (1987): brown coals and lignites – determination of moisture content – indirect gravimetric method.– institute for standardization of serbia, belgrade, serbia, 5 p. (in serbian). srps iso/iec 17025:2006 (2006): general requirements for the competence of testing and calibration laboratories.– institute for standardization of serbia, belgrade, serbia, 59 p. (in serbian). stevanović, p. (1951): pontische stufe im engeren sinne­obere congerienschichten serbiens und der angrenzenden gebiete.– serbische akademie der wissenschaf­ ten, bd. clxxxvii, no.2, 293–361 (in german). sutcu, e.c. & karayigit, a.i. (2015): mineral matter, major and trace element content of the afşin­elbistan coals, kahramanmaraş, turkey.– international jour­ nal of coal geology, 144, 111–129. swaine, d.j. (1990): trace elements in coal.– butterworth & co. ltd, london. 278 p. swaine, d.j. & goodarzi, f. (eds.) (1995): environmental aspects of trace ele­ ments in coal.– kluwer acad. publ, the netherlands, 312 p. doi: 10.1007/978­94­ 015­8496­8 sykorova, i., pickel, w., christanis, k., wolf, m., taylor, g.h. & flo­ res, d. (2005): classification of huminite­iccp system 1994.– international journal of coal geology, 62, 85–106. sztanó, o., száfian, p., magyar, i., horányi, a., bada, g., hughes, d.w., hoyer, d.l. & wallis, r.j. (2013): aggradation and progradation controlled clinothems and deep­water sand delivery model in the neogene lake pannon, makó trough, pannonian basin, se hungary.– global planetary change, 103, 149–167. taylor, g.h., teichmüller, m., davis, a., diessel, c.f.k., littke, r. & robert, p. (1998): organic petrology.– gebrüder borntraeger, berlin. vassilev, s. & vassileva, c. (1998): comparative chemical and mineral charac­ terization of some bulgarian coals.– fuel processing technology, 55, 55–69. doi: 10.1016/s0378­3820(97)00079­9 vassilev, s. & vassileva, c. (2009): a new approach for the combined chemical and mineral classification of the inorganic matter in coal. 1. chemical and mine­ ral classification systems.– fuel, 88, 235–245. doi: 10.1016/j.fuel.2008.09.006 vassilev, s.v., eskenazy, g.m. & vassileva, c.g. (2001): behaviour of ele­ ments and minerals during preparation and combustion of the pernik coal, bul­ garia.– fuel procesing technology, 72, 103–129. doi: 10.1016/s0378­3820(01) 00186­2 vassilev, s., vassileva, c., baxter, d. & andersen, l k. (2009): a new approach for the combined chemical and mineral classification of the inorganic matter in coal. 2. potential applications of the classification systems.– fuel, 88, 246–254. doi: 10.1016/j.fuel.2008.09.005 vassilev, s.v., vassileva, c.g., karayigit, a.i., bulut, y., alastuey, a. & querol, x. (2005): phase­mineral and chemical composition of composite samples from feed coals, bottom ashes and fly ashes at the soma power station, turkey.– international journal of coal geology, 61/(1–2), 35–63. doi: 10.1016/j. coal.2004.06.004 vassileva, c. & vassilev, s. (2005): behaviour of inorganic matter during heating of bulgarian coals. 1. lignites.– fuel processing technology, 86, 1297–333. ward, c.r. (2002): analysis and significance of mineral matter in coal seams.– inter­ national journal of coal geology, 50, 135–168. doi: 10.1016/s0166­5162(02) 00117­9 ward, c.r. (2016): analysis, origin and significance of mineral matter in coal: an up­ dated review.– international journal of coal geology, 165, 1–27. doi: 10.1016/j. coal.2016.07.014 yudovich, ya.e. (1978): geochemistry of fossil coals.– nauka, leningrad [“sci­ ence” pub. house], 262 p. (in russian). yudovich, ya.e. & ketris, m.p. (2002): inorganic matter of coals. uro ran. ekaterinburg [ural division of the russian acad. sci.], 422 p. (in russian). yudovich, ya.e. & ketris, m.p. (2005a): arsenic in coal: a review.– internatio­ nal journal of coal geology, 61, 141–196. doi: 10.1016/j.coal.2004.09.003 yudovich, ya.e. & ketris, m.p. (2005b): toxic trace elements in coal. uro ran, ekaterinburg [ural division of the russian acad. sci.], 655 p. (in russian). yudovich, ya.e. & ketris, m.p. (2006): selenium in coal: a review.– internatio­ nal journal of coal geology, 67, 112–126. doi: 10.1016/j.coal.2005.09.003 yudovich, ya.e., ketris, m.p. & merts, a.v. (1985): trace elements in fossil coals.– nauka, leningrad [“science” pub. house], 239 p. (in russian). zhang, y., tian, j., feng, s., yang, f. & lu, x. (2018): the occurrence modes and geologic origins of arsenic in coal from santanghu coalfield, xinjiang.– jour­ nal of geochemical exploration, 186, 225–234. doi: 10.1016/j.gexplo.2017.12.006 životić, d., ercegovac, m. & milivojević, j. (2005): petrographic composi­ tion and genesis of coal from the kovin deposit.– 14th congress of geologists of serbia and montenegro, 18–20 october, novi sad, book of abstracts, p. 322. (isbn 86­86053­00­9). životić, d., simić, v., gržetić, i. & lorenz, h. (2015): potentially toxic trace elements in some serbian brown coals.– reports of the serbian geological soci­ ety (for the year 2015), 1–14. serbian geological society, belgrade, issn 0372­ 9966. životić, d., wehner, h., ostertag­henning, c., ercegovac, m., schee­ der, g., jovančićević, b., cvetković, o., gržetić, i., milivojević, j., stojanović, k. & šajnović, a. (2007): the organic geochemical, petro­ graphical and palynological composition of coal from the kovin deposit (serbia).– abstract book 23rd international meeting on organic geochemistry. torquay, en­ gland, 565–566. (isbn 978­0­9556551­0­4). g eologia c roatica životić et al.: distribution of major and trace elements in the kovin lignite (serbia) 69 table s–i. list of samples with depth, field, coal seam and lithology of the kovin lignite (after mitrović et al., 2016, 2017). no borehole id field coal seam sample id depth lithology 1 kb–79 b ii 2/79 35.35–36.00 mc 2 ii 3/79 36.80–37.60 mxc 3 ii 4/79 38.00–38.20 xc 4 ii 5/79 38.50–39.00 mxc 5 ii 6/79 39.00–39.10 mmic 6 ii 8/79 40.15–40.65 mxc 7 iii 11/79 67.90–69.30 mmic 8 iii 14/79 114.10–114.25 xc 9 iii 15/79 114.45–114.75 mxc 10 iii 16/79 114.75–114.85 xc 11 iii 17/79 115.00–115.30 mmic 12 iii 18/79 115.30–115.45 mxc 13 iii 19/79 115.45–116.00 mmic 14 iii 20/79 116.05–116.30 mmic 15 iii 21/79 116.30–116.60 mic 16 24/79 247.65–248.05 mxc 17 kb–91 b i 26/91 22.50–24.25 mc 18 i 27/91 24.60–25.00 xc 19 i 28/91 25.50–25.75 mc 20 i 29/91 25.75–26.35 xc 21 i 30/91 26.35–27.65 mc 22 i 31/91 27.65–28.15 mmic 23 ii 33/91 45.00–45.60 mxc 24 ii 34/91 45.60–46.05 xc 25 ii 36/91 47.05–48.35 mmic 26 ii 37/91 48.60–49.30 mxc 27 ii 38/91 49.30–49.50 xc 28 ii 39/91 50.60–50.90 mmic 29 ii 40/91 51.60–52.85 mc 30 gd-601 a i (ia) 42/601 42.65–43.10 xc 31 i (ia) 43/601 43.10–43.50 mc 32 i (ib) 44/601 73.70–75.50 mxc 33 i (ib) 45/601 75.50–76.00 mxc 34 i (ib) 46/601 76.00–76.40 mc 35 ii 47/601 95.30–95.80 mxc 36 ii 48/601 96.40–97.00 mmic 37 ii 49/601 97.00–97.50 mc 38 gd-603 a i (ia) 50/603 39.00–39.55 xc 39 i (ib) 51/603 65.15–65.35 mc 40 i (ib) 52/603 65.60–65.70 xc 41 i (ib) 53/603 65.70–66.65 mxc 42 ii 54/603 88.00–88.12 xc 43 ii 55/603 88.40–88.60 mxc 44 ii 56/603 88.60–88.80 mmic mc – stratified matrix coal (weakly gelified); xc – xylite-rich coal; mxc – mixture of matrix and xylite-rich coal and mixture of xylite-rich and matrix coal; mmic – mixture of matrix and mineral-rich coal; mic – mineral-rich coal (taylor et al., 1998). supplementary material g eo lo gi a c ro at ic a geologia croatica 72/170 table s-ii. results of proximate and ultimate analyses of individual samples (after mitrović et al., 2017 adopted). sample id coal seam proximate analyses war (wt.%) wan (wt.%) adb (wt.%) sdb (wt.%) vdb (wt.%) qg daf (mj/kg) qn daf (mj/kg) 2/79 ii 50.68 6.52 19.00 1.88 46.29 25.9 24.8 3/79 ii 30.36 5.99 59.84 1.67 26.57 18.9 17.8 4/79 ii 50.07 3.80 20.63 2.87 42.29 26.1 25.1 5/79 ii 47.11 2.95 28.02 0.78 38.98 24.8 23.7 6/79 ii 27.81 5.60 63.83 0.51 23.13 17.9 17.0 8/79 ii 48.08 5.38 25.70 3.34 42.85 25.1 23.9 11/79 iii 13.78 4.10 78.20 0.21 11.38 15.7 14.3 14/79 iii 52.89 4.78 12.62 1.53 46.71 26.3 25.3 15/79 iii 49.31 4.23 22.62 1.24 41.47 25.9 24.9 16/79 iii 54.13 10.38 8.66 1.33 43.11 25.6 24.6 17/79 iii 32.55 7.49 56.29 0.82 23.45 23.5 22.5 18/79 iii 47.28 11.09 27.62 1.45 37.81 24.2 23.3 19/79 iii 48.15 12.73 25.51 1.70 41.15 25.8 24.8 20/79 iii 31.34 4.48 58.27 2.13 23.18 21.3 20.3 21/79 iii 11.79 1.90 65.96 0.56 9.67 18.7 18.2 24/79 47.84 11.08 26.26 1.83 39.13 26.3 25.4 26/91 i 40.08 6.78 42.91 1.80 35.44 23.3 22.1 27/91 i 51.08 11.08 17.90 1.98 46.97 25.1 24.1 28/91 i 35.75 9.75 50.85 1.73 27.95 23.0 21.7 29/91 i 50.28 7.85 20.08 1.41 47.48 25.3 24.2 30/91 i 41.18 9.82 40.76 3.33 33.81 22.8 22.1 31/91 i 34.76 6.75 52.56 4.40 29.88 21.0 20.1 33/91 ii 43.54 11.70 35.95 1.46 37.97 24.3 23.3 34/91 ii 49.65 4.26 21.74 1.65 45.34 25.9 24.8 36/91 ii 32.66 4.02 56.11 1.35 28.08 21.2 19.9 37/91 ii 51.59 11.60 16.47 3.12 48.33 25.6 24.6 38/91 ii 51.62 7.16 16.38 0.80 46.09 25.5 24.4 39/91 ii 43.01 10.05 37.05 1.00 36.69 24.4 23.3 40/91 ii 42.59 6.76 37.92 0.92 35.49 23.9 22.6 42/601 i (ia) 45.65 9.03 31.36 2.28 40.78 24.2 23.2 43/601 i (ia) 44.35 10.02 34.23 2.85 37.73 24.3 23.3 44/601 i (ib) 47.21 12.02 27.78 3.96 45.02 25.1 24.2 45/601 i (ib) 43.79 6.66 35.43 1.86 38.44 23.8 22.7 46/601 i (ib) 48.60 12.38 24.40 1.69 42.75 23.4 22.5 47/601 ii 49.92 4.77 21.03 2.26 44.50 25.8 24.7 48/601 ii 31.66 4.91 57.75 2.94 25.88 20.2 19.1 49/601 ii 44.40 4.77 34.11 0.97 38.30 24.2 23.1 50/603 i (ia) 50.79 5.84 18.69 1.67 45.47 26.0 24.9 51/603 i (ib) 51.45 9.89 16.86 0.82 46.88 28.3 27.2 52/603 i (ib) 52.90 15.24 12.58 1.68 44.02 26.4 25.5 53/603 i (ib) 34.57 7.24 52.90 1.63 29.26 22.3 21.1 54/603 ii 52.48 10.68 13.85 1.67 50.26 27.8 26.7 55/603 ii 23.67 4.14 54.98 1.07 19.29 21.7 20.9 56/603 ii 14.42 8.53 68.60 0.22 12.10 16.9 16.3 war – moisture content, as received basis, %; wan – analytical moisture content, %; adb – ash content, dry basis, %; sdb – total sulphur content, dry basis wt.%; vdb – volatile matter, dry basis wt.%; q daf g – gross calorific value, dry, ash-free basis, mj/kg; q daf n – net calorific value, dry, ash-free basis, mj/kg; cdaf – carbon content, dry, ash-free basis, %; hdaf – hidrogen content, dry, ash-free basis, %; ndaf – nitrogen content, dry, ash-free basis; odaf – oxigen content, dry, ash-free basis. g eologia c roatica životić et al.: distribution of major and trace elements in the kovin lignite (serbia) 71 table s-ii. continued. sample id ultimate analyses c daf (wt.%) h daf (wt.%) n daf (wt.%) o daf (wt.%) 2/79 66.75 5.25 1.20 24.48 3/79 59.71 5.18 1.39 29.56 4/79 66.01 4.51 1.01 24.85 5/79 65.34 5.18 1.21 27.19 6/79 52.25 4.56 1.35 40.42 8/79 64.35 5.20 0.81 25.15 11/79 57.43 6.65 1.51 33.12 14/79 66.33 4.82 1.05 26.05 15/79 65.90 5.05 1.09 26.37 16/79 66.67 3.92 1.08 26.88 17/79 68.59 4.37 1.21 23.95 18/79 68.68 4.23 1.22 23.88 19/79 70.45 4.31 1.17 21.79 20/79 65.37 4.96 1.32 23.25 21/79 55.23 2.61 0.79 41.09 24/79 63.36 4.03 0.68 29.45 26/91 61.88 5.27 0.79 28.90 27/91 66.83 4.35 1.11 25.30 28/91 61.32 6.53 1.89 26.73 29/91 63.56 4.79 0.93 28.96 30/91 56.48 2.95 1.22 33.73 31/91 62.23 4.28 1.37 22.85 33/91 66.93 4.34 1.22 25.23 34/91 64.13 5.12 0.97 27.66 36/91 63.41 6.31 0.89 26.31 37/91 70.09 4.44 1.04 20.77 38/91 66.50 4.76 1.08 26.70 39/91 64.62 4.65 0.97 28.16 40/91 74.02 6.11 1.34 17.06 42/601 64.58 4.66 1.02 26.41 43/601 65.50 4.56 1.31 24.30 44/601 66.81 4.03 1.15 22.53 45/601 64.64 4.99 1.10 26.39 46/601 67.06 4.17 1.22 25.32 47/601 64.80 5.17 0.99 26.19 48/601 58.30 5.33 1.11 28.31 49/601 64.61 5.43 0.90 27.59 50/603 66.12 5.02 0.96 25.86 51/603 73.24 4.78 0.90 20.09 52/603 69.55 3.80 1.43 23.30 53/603 61.97 5.41 1.38 27.77 54/603 69.47 5.01 0.87 22.70 55/603 62.08 3.84 0.64 29.87 56/603 60.16 2.96 0.89 35.71 table s-iii. quantitative mineralogical composition of the kovine lignite ashes (450°c) by xrpd analysis (wt.%; on organic matter-free basis) of individual samples. sample id coal seam illite/ smectite quartz anhydrite plagioclase hematite calcite 2/79 ii 23.0 10.5 47.0 2.6 8.4 8.5 3/79 ii 45.3 27.9 14.8 7.1 3.1 1.8 4/79 ii 21.5 13.3 42.6 4.0 18.6 0 5/79 ii 50.3 19.1 9.6 4.5 0.3 16.3 6/79 ii 73.6 19.9 0 2.5 0 4.0 8/79 ii 33.0 11.0 36.1 0.5 18.2 1.2 11/79 iii 20.4 62.4 0.6 15.4 0.1 1.2 14/79 iii 17.6 15.8 42.8 6.6 5.7 11.4 15/79 iii 18.4 45.4 15.9 13.1 4.5 2.8 16/79 iii 11.7 6.0 47.7 1.7 4.6 28.4 17/79 iii 13.9 61.5 4.7 17.2 2.5 0.4 18/79 iii 30.6 37.1 16.8 11.2 1.4 3.0 19/79 iii 30.8 25.5 29.7 6.3 5.4 2.3 20/79 iii 12.7 67.2 5.6 12.9 1.6 0 21/79 iii 15.1 69.3 1.6 13.3 0.6 0.1 24/79 14.8 50.7 13.5 17.4 3.6 0 26/91 i 42.3 29.4 14.8 4.7 6.0 2.8 27/91 i 22.3 10.1 45.6 2.5 15.2 4.3 28/91 i n.a n.a n.a n.a n.a n.a 29/91 i 35.3 19.2 30.9 4.2 7.9 2.6 30/91 i 28.9 28.6 28.4 3.4 9.8 0.9 31/91 i n.a n.a n.a n.a n.a n.a 33/91 ii 47.7 28.3 12.4 4.3 3.5 3.9 34/91 ii 47.8 15.9 24.6 2.6 6.1 3.1 36/91 ii 53.8 27.5 9.3 4.1 3.4 1.9 37/91 ii 19.9 8.6 50.7 0.8 19.6 0.4 38/91 ii 25.0 30.4 12.1 12.0 0.3 20.3 39/91 ii 40.2 37.2 9.4 8.3 1.7 3.3 40/91 ii 63.2 15.1 9.9 8.7 0 3.3 42/601 i (ia) 18.3 37.8 24.4 7.9 7.0 4.6 43/601 i (ia) 13.6 51.7 18.9 8.9 7.0 0 44/601 i (ib) 23.9 12.0 45.0 2.0 17.1 0.01 45/601 i (ib) 38.8 20.2 24.9 5.5 8.1 2.6 46/601 i (ib) 17.5 52.6 13.1 11.0 4.7 1.1 47/601 ii 34.8 14.6 34.2 3.4 11.3 1.7 48/601 ii 43.4 23.6 15.0 6.9 9.1 1.9 49/601 ii 43.5 37.6 10.3 6.6 0.5 1.5 50/603 i (ia) 20.0 24.5 38.6 4.7 9.8 2.4 51/603 i (ib) 25.1 37.4 16.7 5.9 0 14.9 52/603 i (ib) 12.1 4.0 52.3 0.7 5.7 25.3 53/603 i (ib) 46.7 22.6 17.4 8.8 4.4 0.3 54/603 ii 14.8 14.3 54.6 3.9 9.5 2.9 55/603 ii 22.4 57.2 6.2 10.0 1.7 2.5 56/603 ii 36.5 45.1 3.2 11.9 0.8 2.6 n.a – not analysed. g eo lo gi a c ro at ic a geologia croatica 72/172 table s-iv. content of major elements (%) of individual samples. sample id coal seam si al si/al fe ti ca mg na k mn 2/79 ii 2.55 1.19 2.15 1.51 0.04 2.15 0.42 0.08 0.09 0.038 3/79 ii 12.68 5.72 2.22 3.45 0.25 1.12 0.41 0.13 0.18 0.013 4/79 ii 3.10 1.53 2.03 2.80 0.08 1.33 0.35 0.05 0.09 0.011 5/79 ii 0.40 0.20 2.03 0.36 0.01 0.17 0.04 0.01 0.01 0.001 6/79 ii 13.46 4.49 3.00 2.51 0.31 0.95 0.18 0.09 0.19 0.010 8/79 ii 4.36 2.72 1.61 3.25 0.09 1.22 0.38 0.04 0.15 0.008 11/79 iii 21.84 4.37 5.00 3.70 0.25 1.05 0.44 0.49 0.55 0.034 14/79 iii 1.50 0.66 2.26 1.00 0.03 1.92 0.36 0.13 0.04 0.008 15/79 iii 4.48 1.79 2.50 1.02 0.09 1.55 0.37 0.18 0.16 0.009 16/79 iii 0.34 0.26 1.28 0.80 0.01 2.10 0.33 0.11 0.02 0.011 17/79 iii 14.53 3.08 4.72 1.79 0.20 1.83 0.48 0.61 0.52 0.021 18/79 iii 6.46 2.28 2.84 1.59 0.10 1.99 0.42 0.25 0.24 0.014 19/79 iii 4.83 2.56 1.89 1.31 0.12 2.04 0.44 0.16 0.12 0.009 20/79 iii 13.35 2.84 4.71 2.95 0.15 1.56 0.41 0.50 0.38 0.015 21/79 iii 19.79 3.70 5.34 3.00 0.29 0.98 0.36 0.64 0.46 0.016 24/79 6.85 1.57 4.36 1.73 0.10 0.94 0.27 0.45 0.25 0.013 26/91 i 9.01 4.68 1.93 2.61 0.16 1.14 0.36 0.09 0.13 0.015 27/91 i 2.30 1.38 1.67 1.99 0.05 1.88 0.32 0.04 0.05 0.016 28/91 i 11.87 3.46 3.43 2.48 0.16 1.76 0.51 0.29 0.33 0.030 29/91 i 3.84 2.18 1.76 1.49 0.08 1.38 0.30 0.05 0.08 0.014 30/91 i 8.19 4.06 2.02 3.71 0.15 1.64 0.42 0.10 0.16 0.018 31/91 i 9.77 1.58 6.17 9.01 0.09 1.44 0.28 0.33 0.26 0.154 33/91 ii 7.60 3.65 2.08 2.60 0.13 1.68 0.59 0.06 0.25 0.021 34/91 ii 3.92 1.80 2.18 1.83 0.06 1.56 0.42 0.05 0.17 0.016 36/91 ii 12.75 5.02 2.54 3.52 0.24 1.00 0.34 0.09 0.14 0.014 37/91 ii 2.32 1.44 1.61 2.43 0.05 1.55 0.35 0.04 0.07 0.015 38/91 ii 2.68 1.34 2.00 0.78 0.04 1.88 0.41 0.08 0.09 0.019 39/91 ii 8.80 3.76 2.34 1.84 0.15 1.33 0.47 0.15 0.26 0.014 40/91 ii 8.38 3.99 2.10 1.89 0.14 1.32 0.49 0.09 0.25 0.013 42/601 i (ia) 6.08 2.26 2.69 2.60 0.14 1.96 0.41 0.15 0.17 0.017 43/601 i (ia) 7.60 2.35 3.23 2.73 0.16 1.96 0.54 0.18 0.15 0.018 44/601 i (ib) 4.86 2.52 1.93 3.55 0.09 2.14 0.54 0.09 0.14 0.018 45/601 i (ib) 6.68 2.91 2.30 2.67 0.11 3.19 0.58 0.11 0.12 0.027 46/601 i (ib) 7.83 2.08 3.76 2.46 0.09 2.05 0.45 0.17 0.17 0.031 47/601 ii 3.88 1.89 2.06 2.39 0.06 1.53 0.43 0.08 0.12 0.014 48/601 ii 12.00 3.87 3.10 5.03 0.22 1.18 0.29 0.11 0.20 0.017 49/601 ii 7.43 3.17 2.35 1.75 0.11 1.52 0.56 0.14 0.31 0.014 50/603 i (ia) 3.07 1.17 2.61 1.86 0.05 1.91 0.39 0.10 0.09 0.015 51/603 i (ib) 2.32 0.95 2.44 0.59 0.04 1.54 0.25 0.12 0.08 0.017 52/603 i (ib) 0.88 0.52 1.72 1.48 0.02 2.68 0.42 0.15 0.04 0.016 53/603 i (ib) 11.69 5.15 2.27 4.00 0.18 1.44 0.67 0.12 0.44 0.014 54/603 ii 1.97 0.88 2.24 1.30 0.04 1.57 0.23 0.09 0.06 0.016 55/603 ii 16.84 5.07 3.33 2.29 0.21 1.73 0.50 0.36 0.31 0.026 56/603 ii 17.33 3.38 5.12 3.73 0.32 1.06 0.26 0.28 0.20 0.019 g eologia c roatica životić et al.: distribution of major and trace elements in the kovin lignite (serbia) 73 table s-iv. continued. sample id coal seam rb sb sc se sr th tl v zn 2/79 ii 7.0 < 0.5 2.8 1.7 116.7 0.7 < 0.5 31.0 38.0 3/79 ii 4.2 < 0.5 14.5 3.0 69.1 2.1 < 0.5 110.8 66.0 4/79 ii 6.2 < 0.5 5.0 2.3 79.8 1.0 < 0.5 49.8 31.0 5/79 ii 0.8 < 0.5 0.6 0.3 10.2 0.1 < 0.5 6.4 4.0 6/79 ii < 0.5 < 0.5 15.1 2.5 58.0 0.9 < 0.5 89.4 59.4 8/79 ii 15.7 < 0.5 8.1 2.0 73.9 1.9 < 0.5 78.7 47.5 11/79 iii 14.2 < 0.5 8.1 1.9 120.7 2.8 < 0.5 49.7 62.5 14/79 iii 0.8 < 0.5 3.2 1.2 201.7 < 0.1 < 0.5 16.3 4.3 15/79 iii 11.7 < 0.5 4.7 1.9 183.9 1.4 < 0.5 34.0 16.5 16/79 iii < 0.5 < 0.5 0.6 0.9 210.3 < 0.1 < 0.5 3.3 9.1 17/79 iii 36.3 < 0.5 5.1 3.6 204.4 2.5 < 0.5 30.9 35.6 18/79 iii 18.0 < 0.5 5.0 1.8 175.7 1.9 < 0.5 35.4 27.2 19/79 iii 9.3 < 0.5 6.2 4.3 218.9 1.9 < 0.5 54.5 39.2 20/79 iii 24.9 < 0.5 4.7 2.6 186.7 1.8 < 0.5 31.5 43.6 21/79 iii 10.9 < 0.5 7.1 3.5 155.3 2.9 < 0.5 43.0 43.0 24/79 14.9 < 0.5 3.0 1.4 221.6 1.1 < 0.5 29.6 25.6 26/91 i 3.0 < 0.5 8.7 1.9 46.0 1.2 < 0.5 47.6 49.6 27/91 i 2.4 < 0.5 2.8 1.5 65.9 0.1 < 0.5 25.4 15.4 28/91 i 21.1 < 0.5 6.7 2.4 113.8 2.5 < 0.5 59.0 31.1 29/91 i 5.2 < 0.5 4.0 1.7 53.7 0.7 < 0.5 33.1 16.6 30/91 i 7.6 < 0.5 8.3 4.4 68.3 2.4 < 0.5 48.1 82.6 31/91 i 18.0 < 0.5 5.8 9.0 77.1 0.6 < 0.5 54.0 56.1 33/91 ii 15.7 < 0.5 8.2 2.7 94.8 2.6 < 0.5 61.1 44.4 34/91 ii 18.8 < 0.5 4.5 1.6 81.5 1.7 < 0.5 38.1 41.6 36/91 ii 1.2 < 0.5 12.8 3.5 58.6 1.6 < 0.5 100.3 57.9 37/91 ii 6.2 < 0.5 3.1 1.8 78.7 0.4 < 0.5 23.1 11.0 38/91 ii 7.9 < 0.5 3.1 1.6 98.8 0.3 < 0.5 17.5 23.9 39/91 ii 7.3 < 0.5 7.9 1.4 82.5 1.6 < 0.5 50.1 65.8 40/91 ii 9.9 < 0.5 8.3 2.0 77.4 1.4 < 0.5 55.1 56.4 42/601 i (ia) 5.3 4.3 7.6 4.6 65.4 2.0 < 0.5 47.8 174.8 43/601 i (ia) 6.2 < 0.5 11.1 3.6 61.4 1.3 < 0.5 46.8 68.1 44/601 i (ib) 10.5 < 0.5 7.0 2.7 97.4 1.7 < 0.5 52.8 42.8 45/601 i (ib) 8.0 < 0.5 4.8 3.5 108.5 1.1 < 0.5 30.7 31.9 46/601 i (ib) 10.5 < 0.5 5.8 2.7 99.6 1.5 < 0.5 60.9 23.4 47/601 ii 13.6 < 0.5 4.5 2.6 106.7 0.9 < 0.5 35.8 157.9 48/601 ii 2.7 < 0.5 10.8 2.3 82.5 1.7 < 0.5 67.2 239.7 49/601 ii 33.0 < 0.5 6.1 1.8 105.1 1.7 < 0.5 42.0 155.5 50/603 i (ia) 5.5 < 0.5 3.0 1.7 128.8 0.2 < 0.5 17.8 18.0 51/603 i (ib) 5.4 < 0.5 2.1 1.3 177.7 0.2 < 0.5 15.0 26.0 52/603 i (ib) 0.4 < 0.5 1.2 1.6 253.1 < 0.1 < 0.5 7.6 11.2 53/603 i (ib) 36.1 < 0.5 11.2 2.8 94.9 3.7 < 0.5 76.8 98.2 54/603 ii 3.7 < 0.5 2.1 1.4 176.1 0.1 < 0.5 13.3 26.5 55/603 ii 18.2 < 0.5 6.1 3.3 100.7 2.4 < 0.5 49.9 54.4 56/603 ii 7.8 < 0.5 12.9 4.9 136.4 1.9 < 0.5 88.1 144.8 clarke value of brown coala 10 ±0.9 4.1 ±0.2 1.0 ±0.15 120 ±10 3.3 ±0.2 22 ±2 18 ±1 g eo lo gi a c ro at ic a geologia croatica 72/174 table s-v. content of trace elements (mg/kg) of individual samples. sample id coal seam as ba cd co cr cu ga li mo ni pb 2/79 ii 29.5 43.5 1.5 6.4 52.2 21.7 3.2 9.5 4.0 65.1 24.3 3/79 ii 30.3 122.7 2.4 16.9 125.3 69.0 19.8 84.8 7.4 83.2 80.2 4/79 ii 33.6 72.6 1.5 26.3 65.6 24.6 7.0 17.3 5.4 73.4 31.8 5/79 ii 4.3 9.3 0.2 3.4 8.4 3.1 0.9 2.2 0.7 9.4 4.1 6/79 ii < 0.5 170.3 1.4 9.4 127.8 68.9 25.6 75.1 4.9 33.2 56.2 8/79 ii 55.1 78.0 2.4 34.3 83.7 29.7 9.7 33.0 8.3 110.0 46.2 11/79 iii < 0.5 239.8 2.3 15.2 251.7 23.5 16.5 37.9 4.8 77.3 55.4 14/79 iii 11.6 61.2 0.8 2.3 31.2 6.3 3.0 4.3 2.7 15.8 10.4 15/79 iii 11.4 94.8 0.8 25.1 58.4 40.6 5.5 22.6 4.1 26.3 51.5 16/79 iii 13.0 62.7 0.7 1.5 11.9 3.8 1.0 1.7 1.9 9.7 2.8 17/79 iii 4.5 226.3 1.6 24.8 214.5 28.7 8.0 23.3 3.8 43.5 58.3 18/79 iii 18.2 122.6 1.3 13.9 75.9 38.3 6.7 24.0 4.4 77.5 82.1 19/79 iii 21.2 111.4 1.4 11.0 63.8 62.4 7.8 29.4 8.9 44.3 50.3 20/79 iii 9.4 181.7 1.6 11.5 139.5 57.3 10.0 18.2 6.6 61.4 40.1 21/79 iii < 0.5 232.4 2.0 13.5 265.3 59.9 14.6 21.9 5.3 55.0 40.4 24/79 39.0 190.4 2.0 21.8 94.6 5.2 5.4 9.9 3.7 33.2 80.9 26/91 i 10.5 91.1 1.4 7.6 74.1 45.8 14.3 45.4 5.2 31.6 60.2 27/91 i 19.8 74.8 1.1 7.8 41.9 21.0 4.7 8.0 4.4 24.0 19.5 28/91 i 5.7 138.7 1.9 15.3 184.0 28.9 10.4 29.8 4.1 46.7 55.2 29/91 i 16.1 72.0 1.2 7.6 43.0 28.1 6.2 17.2 3.9 64.2 38.8 30/91 i 56.7 123.8 3.1 11.9 108.8 62.6 13.6 35.8 8.9 47.7 76.8 31/91 i 140.0 142.3 6.5 35.8 371.4 3.6 13.4 9.5 8.7 214.0 111.4 33/91 ii 22.8 108.2 1.7 14.6 113.9 58.0 11.7 39.7 4.6 135.1 110.0 34/91 ii 35.0 80.9 1.8 11.1 82.9 34.4 5.8 16.9 6.7 131.7 49.2 36/91 ii 28.7 100.3 2.3 23.2 126.1 65.1 19.4 82.8 7.4 110.6 179.9 37/91 ii 31.8 62.3 1.5 8.6 47.5 11.0 5.7 16.7 4.2 34.8 20.0 38/91 ii 4.4 72.2 0.5 2.5 29.8 11.6 3.4 14.6 1.4 13.2 21.6 39/91 ii 10.5 122.1 1.3 7.3 96.0 46.6 11.2 42.8 4.8 31.2 113.9 40/91 ii 4.6 99.2 1.1 7.0 76.9 41.1 11.9 47.2 4.9 25.2 115.2 42/601 i (ia) 36.7 90.7 2.4 24.5 106.1 45.3 10.1 34.7 11.5 91.5 96.4 43/601 i (ia) 24.3 65.0 2.0 20.1 93.3 27.4 9.5 23.5 7.7 36.2 91.4 44/601 i (ib) 34.9 58.4 2.1 10.5 101.4 54.3 9.3 26.2 8.1 47.3 54.2 45/601 i (ib) 21.5 63.4 1.8 8.0 78.7 38.7 8.9 21.1 5.4 63.3 82.4 46/601 i (ib) 15.8 96.7 1.7 9.8 149.6 24.5 7.4 17.4 5.0 43.0 116.3 47/601 ii 70.4 48.1 3.2 21.9 86.2 39.9 6.7 21.7 6.8 206.1 40.7 48/601 ii 39.1 100.1 2.6 11.9 150.9 30.7 20.0 85.1 9.8 92.9 74.8 49/601 ii 15.8 94.6 1.4 7.7 84.4 29.1 9.8 33.6 4.3 50.6 107.0 50/603 i (ia) 28.1 47.5 1.6 6.5 59.5 15.2 4.3 11.0 4.3 35.7 26.2 51/603 i (ib) 4.0 40.9 0.6 3.4 36.6 8.0 2.1 8.8 1.1 13.7 16.9 52/603 i (ib) 17.7 77.8 0.9 8.8 35.2 3.5 2.3 3.8 2.8 19.5 6.9 53/603 i (ib) 31.1 173.1 2.4 16.7 191.0 72.5 16.3 54.1 8.9 148.5 175.7 54/603 ii 24.9 34.9 1.2 6.6 39.8 8.6 3.2 8.6 2.5 26.9 14.5 55/603 ii 12.7 156.5 2.2 11.3 226.7 71.3 16.2 43.0 4.3 74.5 52.9 56/603 ii < 0.5 138.7 1.7 33.7 216.8 77.2 22.9 46.5 5.6 45.4 70.4 clarke value of brown coala 7.6 ±1.3 150 ±20 0.24 ±0.04 4.2 ±0.3 15 ±1 15 ±1 5.5 ±0.3 10 ±1 2.2 ±0.2 9.0 ±0.9 6.6 ±0.4 a ketris & yudovich (2009) g eologia c roatica životić et al.: distribution of major and trace elements in the kovin lignite (serbia) 75 table s-vi. content of rare earth elements and yttrium (rey, mg/kg) of individual samples. sample id coal seam la ce pr nd sm eu gd tb dy y 2/79 ii 5.78 10.10 3.60 6.20 0.70 0.48 4.76 1.10 1.34 6.64 3/79 ii 4.39 10.30 2.10 4.00 1.50 0.59 13.02 2.60 1.09 6.79 4/79 ii 6.37 13.00 3.10 5.90 1.00 0.59 5.92 < 0.1 1.00 5.94 5/79 ii 0.81 1.70 0.40 0.80 0.10 0.08 0.76 < 0.1 0.13 0.76 6/79 ii 2.11 3.80 0.90 1.50 1.30 0.31 14.38 4.50 0.29 2.39 8/79 ii 7.61 15.40 4.00 8.30 1.70 0.83 7.19 < 0.1 1.94 13.47 11/79 iii 8.24 20.15 5.40 7.70 1.50 0.84 12.92 3.00 1.40 7.11 14/79 iii 3.19 5.80 2.20 3.40 0.50 0.28 3.49 0.70 0.75 5.27 15/79 iii 7.44 12.10 4.20 6.50 0.50 0.40 6.40 < 0.1 1.06 4.77 16/79 iii 1.90 2.70 1.40 1.70 0.10 0.15 2.48 0.50 0.11 0.99 17/79 iii 15.21 21.40 7.10 10.80 0.80 0.70 11.74 0.50 1.63 8.61 18/79 iii 9.28 14.50 4.70 8.00 0.90 0.57 7.94 0.60 1.37 7.60 19/79 iii 8.78 13.80 5.10 8.30 1.00 0.54 8.14 1.20 1.41 7.72 20/79 iii 11.59 19.40 5.40 9.00 1.10 0.78 9.79 1.50 1.41 8.67 21/79 iii 6.80 15.40 3.70 5.90 1.60 0.70 14.57 3.10 1.21 6.85 24/79 8.03 12.65 4.20 5.65 0.50 0.45 6.17 < 0.1 0.91 5.64 26/91 i 3.70 8.50 2.10 3.90 1.20 0.48 8.54 2.10 0.75 4.62 27/91 i 4.16 7.50 2.00 3.70 0.60 0.35 4.37 0.40 0.51 3.30 28/91 i 12.86 18.40 5.30 9.00 1.10 0.71 9.92 1.10 1.64 9.17 29/91 i 5.10 8.00 2.80 4.20 0.50 0.31 5.22 0.90 0.54 3.60 30/91 i 6.53 13.80 2.80 5.40 1.40 0.62 8.66 1.60 0.71 5.11 31/91 i 9.94 28.70 1.80 7.60 2.20 1.59 7.12 < 0.1 2.54 12.79 33/91 ii 10.24 17.80 5.20 9.00 1.10 0.71 8.69 0.80 1.60 9.47 34/91 ii 9.80 17.60 5.40 9.90 0.90 0.71 5.97 < 0.1 1.78 9.55 36/91 ii 3.33 9.00 2.10 2.85 1.50 0.54 11.89 2.25 0.72 5.03 37/91 ii 4.86 10.30 2.60 4.90 0.60 0.48 4.54 0.70 0.76 5.34 38/91 ii 4.01 6.00 2.60 4.00 0.40 0.27 3.95 0.50 0.83 5.03 39/91 ii 6.35 11.40 3.90 6.40 1.20 0.54 8.77 1.70 1.33 8.61 40/91 ii 4.89 9.60 3.00 5.20 1.20 0.50 8.32 2.00 1.17 7.36 42/601 i (ia) 8.46 14.60 4.30 7.90 1.30 0.73 9.58 0.20 1.80 12.34 43/601 i (ia) 8.29 14.70 4.60 8.50 1.70 0.92 11.18 0.90 2.68 17.54 44/601 i (ib) 8.33 16.10 4.40 8.00 1.60 0.80 7.76 0.80 1.63 11.12 45/601 i (ib) 8.31 13.00 3.90 6.50 0.80 0.51 8.46 1.30 0.87 5.11 46/601 i (ib) 8.73 13.95 4.05 6.80 0.90 0.59 7.11 0.75 1.32 7.62 47/601 ii 5.00 9.70 2.90 5.00 1.00 0.51 4.96 < 0.1 1.26 9.56 48/601 ii 4.47 13.50 2.15 4.15 1.60 0.71 11.38 2.50 0.54 4.74 49/601 ii 8.33 12.10 3.80 6.30 0.80 0.46 7.23 1.40 0.93 5.87 50/603 i (ia) 5.26 9.30 3.10 4.70 0.60 0.41 4.63 0.60 0.81 5.70 51/603 i (ib) 3.61 5.00 2.30 2.90 0.20 0.23 3.53 0.50 0.81 4.37 52/603 i (ib) 3.56 5.85 2.00 3.00 0.15 0.25 3.80 < 0.1 0.33 2.09 53/603 i (ib) 11.95 21.20 5.90 10.20 1.90 0.94 11.05 1.40 2.05 14.94 54/603 ii 3.03 5.40 1.80 2.60 0.40 0.25 3.54 0.10 0.49 3.03 55/603 ii 10.77 15.90 4.50 7.70 1.00 0.59 11.93 1.90 1.27 7.57 56/603 ii 6.12 12.50 2.30 4.70 1.40 0.65 15.70 2.00 0.84 4.94 clarke value of brown coala 10 ±0.5 22 ±1 3.5 ±0.3 11 ±1 1.9 ±0.1 0.5 ±0.02 2.6 ±0.2 0.32 ±0.03 2.0 ±0.1 8.6 ±0.4 lrey = la+ce + pr + nd + sm; mrey = eu + gd + tb + dy + y; hrey = ho + er + tm + yb + lu; (seredin & dai, 2012). g eo lo gi a c ro at ic a geologia croatica 72/176 table s-vi. continued. sample id coal seam ho er tm yb lu lreyb mreyb hreyb σrey 2/79 ii 0.32 0.89 0.26 0.81 0.35 26.38 14.54 2.62 43.54 3/79 ii 0.69 1.41 0.20 1.70 0.90 22.29 25.00 4.90 52.19 4/79 ii 0.49 1.10 0.23 1.13 0.67 29.37 13.86 3.61 46.84 5/79 ii 0.06 0.14 0.03 0.14 0.09 3.81 1.75 0.46 6.02 6/79 ii 0.54 0.79 0.09 1.14 0.61 9.61 22.86 3.17 35.64 8/79 ii 0.80 1.92 0.34 2.00 0.89 37.01 24.30 5.95 67.26 11/79 iii 0.87 1.23 0.30 1.36 0.91 42.99 25.26 4.66 72.91 14/79 iii 0.27 0.76 0.26 0.64 0.24 15.09 10.49 2.17 27.75 15/79 iii 0.32 0.80 0.28 0.80 0.27 30.74 12.63 2.47 45.84 16/79 iii 0.05 0.21 0.08 0.15 0.13 7.80 4.23 0.61 12.64 17/79 iii 0.85 1.13 0.36 1.13 0.67 55.31 23.18 4.14 82.63 18/79 iii 0.44 1.08 0.33 1.08 0.44 37.38 18.08 3.37 58.83 19/79 iii 0.48 1.14 0.38 1.19 0.37 36.98 19.01 3.56 59.54 20/79 iii 0.63 1.22 0.25 1.22 0.78 46.49 22.15 4.10 72.74 21/79 iii 0.93 1.22 0.20 1.38 0.85 33.40 26.43 4.58 64.41 24/79 0.34 0.72 0.21 0.75 0.47 31.03 13.16 2.47 46.66 26/91 i 0.42 0.95 0.12 1.02 0.64 19.40 16.49 3.15 39.04 27/91 i 0.18 0.58 0.13 0.60 0.43 17.96 8.93 1.91 28.80 28/91 i 0.71 1.29 0.39 1.42 0.75 46.66 22.54 4.56 73.76 29/91 i 0.26 0.64 0.14 0.63 0.33 20.60 10.57 2.00 33.17 30/91 i 0.51 1.05 0.18 1.13 0.92 29.93 16.70 3.79 50.42 31/91 i 1.35 2.45 0.29 2.71 2.65 50.24 24.04 9.45 83.73 33/91 ii 0.60 1.25 0.36 1.44 0.70 43.34 21.66 4.35 69.35 34/91 ii 0.52 1.20 0.34 1.18 0.49 43.60 18.20 3.73 65.53 36/91 ii 0.58 1.17 0.17 1.48 0.84 18.78 21.39 4.23 44.39 37/91 ii 0.27 0.76 0.23 0.79 0.54 23.26 11.94 2.59 37.79 38/91 ii 0.22 0.63 0.12 0.56 0.19 17.01 10.71 1.72 29.44 39/91 ii 0.49 1.16 0.21 1.21 0.49 29.25 21.61 3.56 54.42 40/91 ii 0.49 1.11 0.18 1.13 0.51 23.89 20.05 3.42 47.36 42/601 i (ia) 0.69 1.87 0.38 1.71 0.75 36.56 24.65 5.40 66.61 43/601 i (ia) 0.86 2.38 0.52 2.45 0.90 37.79 33.22 7.11 78.12 44/601 i (ib) 0.62 1.52 0.31 1.53 0.88 38.43 22.11 4.86 65.40 45/601 i (ib) 0.34 0.83 0.25 0.87 0.60 32.51 16.25 2.89 51.66 46/601 i (ib) 0.50 1.17 0.31 1.20 0.62 34.43 17.38 3.80 55.61 47/601 ii 0.45 1.29 0.32 1.21 0.59 23.60 16.78 3.85 44.23 48/601 ii 0.60 1.22 0.16 1.41 1.19 25.87 20.75 4.58 51.19 49/601 ii 0.44 0.82 0.26 0.90 0.46 31.33 16.23 2.89 50.45 50/603 i (ia) 0.23 0.77 0.25 0.74 0.40 22.96 12.15 2.40 37.51 51/603 i (ib) 0.18 0.49 0.19 0.50 0.14 14.01 9.44 1.50 24.95 52/603 i (ib) 0.04 0.40 0.13 0.31 0.28 14.56 6.46 1.16 22.17 53/603 i (ib) 0.79 1.87 0.52 2.02 1.03 51.15 30.38 6.22 87.75 54/603 ii 0.10 0.52 0.13 0.45 0.26 13.23 7.56 1.46 22.25 55/603 ii 0.77 1.03 0.31 1.26 0.64 39.87 23.67 4.01 67.55 56/603 ii 0.79 1.10 0.17 1.53 1.15 27.02 24.88 4.75 56.65 clarke value of brown coala 0.50 ±0.05 0.85 ±0.08 0.31 ±0.02 1.0 ±0.05 0.19 ±0.02 a ketris & yudovich (2009); b seredin & dai (2012) g eologia c roatica životić et al.: distribution of major and trace elements in the kovin lignite (serbia) 77 table s-vii. continuied. i seam ii seam iii seam al affinity ral= 0.7–1.0 si (0.78), ti (0.87), cu (0.85), ga (0.86), li (0.94), sc (0.79), th (0.81), v (0.73), gd (0.76), tb (0.85). si (0.88), ti (0.84), k (0.74), ba (0.86), cr (0.75), cu (0.86), ga (0.86), li (0.90), pb (0.74), sc (0.86), th (0.76), v (0.84), sm (0.77), eu (0.77), gd (0.88), tb (0.73), ho (0.75). si (0.93), ti (0.95), fe (0.87), k (0.91), na (0.81), mn (0.77), si/al (0.85), ba (0.93), cd (0.96), cr (0.90), ga (0.96), li (0.87), ni (0.82), sc (0.93), th (0.92), v (0.82), zn (0.95), ce (0.90), pr (0.74), nd (0.71), sm (0.93), eu (0.95), gd (0.96), tb (0.75), dy (0.81), y (0.74), ho (0.94), er (0.88), yb (0.95), lu (0.93), lrey (0.81), mrey (0.96), hrey (0.95). ral = 0.5–0.69 mg (0.54), k (0.64), ba (0.61), pb (0.60), rb (0.55), sm (0.54), mrey (0.52). fe (0.60), na (0.53), mo (0.53), se (0.63), er (0.50), yb (0.70), lu (0.63), hrey (0.65). mg (0.62), co (0.54), cu (0.56), mo (0.53), pb (0.63), se (0.58), la (0.63). si affinity rsi= 0.7–1.0 al (0.78), ti (0.85), k (0.87), ba (0.80), cr (0.71), ga (0.88), li (0.71), pb (0.78), rb (0.74), sc (0.78), th (0.75), v (0.88), la (0.80), ce (0.76), nd (0.75), sm (0.75), gd (0.83), ho (0.74), lrey (0.81), mrey (0.75). ti (0.95), na (0.77), ba (0.89), cr (0.93), cu (0.90), ga (0.93), li (0.71), sc (0.82), se (0.80), v (0.76), gd (0.96), tb (0.72), ho (0.75). ti (0.97), fe (0.94), k (0.96), na (0.92), mn (0.83), ba (0.98), cd (0.95), cr (0.98), ga (0.95), ni (0.71), sc (0.79), th (0.90), ce (0.81), sm (0.88), eu (0.90), gd (0.95), tb (0.81), ho (0.95), er (0.74), yb (0.81), lu (0.98), mrey (0.90), hrey (0.88). rsi = 0.5–0.69 fe (0.55), na (0.55), co (0.53), ni (0.54), pr (0.55), eu (0.67), tb (0.63), dy (0.62), y (0.59), er (0.64), tm (0.59), yb (0.69), lu (0.57), hrey (0.69). fe (0.61), k (0.69), pb (0.56), th (0.67), sm (0.67), eu (0.67), yb (0.59), lu (0.69), hrey (0.57). li (0.66), v (0.58), la (0.51), pr (0.59), nd (0.53), dy (0.62), y (0.59), lrey (0.68). table s-vii. element affinities deduced from calculation of pearson’s correlation coefficients between the concentration of each element in the coal and ash yield, si, al and total sulphur content. i seam ii seam iii seam correlation with ash yield rash=0.7–1.0 al (0.75), si (0.95), ti (0.80), k (0.85), ba (0.81), cr (0.75), ga (0.92), pb (0.71), rb (0.73), sc (0.73), v (0.79), la (0.74), ce (0.81), nd (0.70), sm (0.81), eu (0.74), gd (0.78), ho (0.79), yb (0.72), lrey (0.80), mrey (0.72), hrey (0.74). al (0.84), si (0.95), ti (0.97), ba (0.80), cr (0.83), cu (0.84), ga (0.95), li (0.86), sc (0.88), se (0.70), v (0.80), gd (0.93), tb (0.82). al (0.93), si (0.99), ti (0.94), fe (0.95),k (0.97), na (0.92), mn (0.83), si/al (0.96), ba (0.98), cd (0.94), cr (0.96), ga (0.94), ni (0.72), sc (0.77), th (0.82), zn (0.90), ce (0.85), sm (0.86), eu (0.93), gd (0.94), tb (0.77), ho (0.94), er (0.76), yb (0.82), lu (0.99), lrey (0.74), mrey (0.91), hrey (0.89). rash=0.50–0.69 fe (0.68), na (0.56), cd (0.65), co (0.62), li (0.68), mo (0.56), ni (0.65), se (0.59), th (0.67), tb (0.69), dy (0.62), y (0.57), er (0.66), tm (0.51), lu (0.69). fe (0.63), k (0.55), na (0.59), pb (0.54), th (0.58), sm (0.66), eu (0.66), ho (0.66), yb (0.53), lu (0.68), hrey (0.50). li (0.66), v (0.58), la (0.57), pr (0.64), nd (0.59), dy (0.66), y (0.63). rash=0.35–0.49 sdb (0.41), mg (0.40), mn (0.45), as (0.45), cu (0.48), zn (0.44), pr (0.42). mo (0.42), zn (0.45). mg (0.49), co (0.43), cu (0.39), mo (0.32), pb (0.41), rb (0.47), se (0.42). rash=−0.34–0.34 ca (-0.33). mg (-0.11), mn (-0.05), as (-0.13), cd (0.32), co (0.28), ni (-0.02), rb (-0.01), sr (-0.18), la (-0.04), ce (0.07), pr (-0.22), nd (-0.22), dy (-0.23), y (-0.19), er (0.23), tm (-0.22), lrey (-0. 03), mrey (0.01). tm (0.22). rash=−1.0– -0.35 sr (-0.45). sdb (-0.40), ca (-0.41). ca (-0.81), as (-0.52), sr (-0.72). correlation with total sulphur content rstot=0.7–1.0 fe (0.79), as (0.79), cd (0.78), se (0.76). as (0.76). rstot=0.5–0.69 mn (0.60), co (0.65), cr (0.58), mo (0.66). mo (0.50). sr (0.69). rstot=0.35–0.49 na (0.35), ga (0.47), ni (0.49), sc (0,35), v (0.37). fe (0.39), cd (0.48), ni (0.42). as (0.38). sdb – total sulphur content, dry basis wt.% g eo lo gi a c ro at ic a geologia croatica 72/178 figure s1. x-ray diffraction patterns of lignite ash (450oc) of individual samples of boreholes gd-601 (a) and gd-603 (b) in the a field. g eologia c roatica životić et al.: distribution of major and trace elements in the kovin lignite (serbia) 79 figure s2. x-ray diffraction patterns of lignite ash (450oc) of individual samples of boreholes kb-79 (a) and kb-91 (b) in the b field. www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2025 | 78/1 | 87–101 | 4 figs. | 7 tabs. | article history: manuscript received: february 12, 2024 revised manuscript accepted: november 19, 2024 available online: february 27, 2025 keywords: critical raw materials, magnesium, dolostone, croatia 1. introduction in general, local societies are rarely aware of the mining activities in their states, and like to perceive their countries as touristic, agricultural, or industrial, but certainly not as “mining”. the average croatian citizen would hardly ever wonder about the type of mineral raw material that is imbedded in roads, viaducts, tunnels and bridges on their way to the adriatic seaside or used as a light alloy for manu­ facturing the car that they are driving, or that is built into the insulating lining of their seaside apartment, as long as these products serve their purposes at reasonable costs. however, when the roads, tunnels or viaducts are damaged and need costly reconstruction, or when expenses for the heating/ cooling of apartments and houses doubles or triples, then the wider society will start to wonder about the quality and origin croatian critical mineral commodity letters: magnesium sibila borojević šoštarić1,*, nenad tomašić2, vječislav bohanek1, nikola gizdavec3 and slobodan miko3 1 university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, 10000 zagreb, croatia; (*corresponding author: sibila.borojevic-sostaric@rgn.unizg.hr) 2 university of zagreb, faculty of science, horvatovac 102a, 10000 zagreb, croatia 3 croatian geological survey, milana sachsa 2, 10000 zagreb, croatia doi: 10.4154/gc.2025.04 abstract magnesium is a critical raw material of high importance to the european union economy. magnesium has versatile applications in many industries: the automotive industry (48%), packaging applications (23%), the construction industry (13%), desulphurisation of steel (12%), heavy transportation (air, marine, train; 4%) as well as in medical equipment, sport applications, electrochemical and organic chemistry applications. the republic of croatia hosts two major sources of magnesium: (1) primary dolostone deposits and occurrences, mainly used as a high-quality crushed stone aggregate and carbonate mineral raw material for industrial processing, and (2) secondary mg reject brine from the nin, pag and ston saltpans: (1) deposits and occurrences of early and late diagenetic dolostone are associated with the south tethyan megaplatform (stm; upper triassic hauptdolomite and lower jurassic limestone and dolostone) or the adriatic carbonate platform (adcp; jurassic limestone and dolostone and upper jurassic boundstones, layered and massive dolostone and lower to middle cretaceous dolostone and post-sedimentary, diagenetic breccia). based on their lithological, mineralogical, and chemical characteristics, stm deposits are considered high-potential magnesium sources, whereas adcp deposits belong to medium-to-high (jurassic) and low-potential (cretaceous) magnesium sources. the overall geological potential of primary magnesium sources at a scale of 1:300,000 has been calculated by excluding areas where exploitation is prohibited. in the resulting areas, exploitation is possible, but additional restrictions arising from the three levels of spatial plans (national, county, and local) must additionally be taken into account. (2) average annual salt production in croatia is around 20,000 t. the calculated amount of discharged magnesium from highsaline brines remaining after the precipitation of sodium-chloride is about 2.38 t/annually. the case study on the đipalo dolostone deposit near sinj (stm dolostone; exploitation reserves of 5.9 mt) shows high purity dolostone with mgo > 22 wt%, whereas the sum content of sio2, fe2o3 and al2o3 remains below 1 wt%. the đipalo dolostone can be used in the refractory material industry, as an agent of fusion in ferrous metallurgy, in the production of cement, glass, ceramics, paper or for magnesium metal production. the prices of various mg-products range from 1.7 €/t construction mineral raw material, 10 €/t for crushed stone aggregate, 100 €/t for refractory (roasted) dolostone and about 2,250 €/t for 99,0% pure magnesium (february 2024). dolostone consumption for the đipalo deposit is estimated to be about 10-15 t of dolostone per tonne of mg metal produced, depending on the process, however, the estimated co2 emissions remain a significant negative factor. of the mineral raw materials that were initially used, and most importantly on the quantities of the complementary material left for disposal. at this point, the average citizen might ask himself “are we doing any mining and extraction in croatia?” croatian critical mineral commodity letters are a serial of review publications focused on selected critical raw materials (crm) in croatia. critical raw materials are non­ energy raw materials of high importance to the european union’s economy across the industrial value chain, irreplaceable in modern and environmental­friendly clean technologies such as solar panels, wind turbines, electric vehicles, and energy-efficient lighting. at the same time, there is a high risk associated with their supply, where the eu mainly relies on their import (grohol & veeh, 2023). g eo lo gi a c ro at ic a 88 geologia croatica 78/1 the aims of this series of publications are raising awareness of the croatian mineral raw materials stakeholders (industry, research, academia, policymakers, investors), as well as the local community on the existence of valuable crm recourses that exist, but are not being exploited in croatia, providing a state of the art literature overview and offering evaluation of the economic potential of selected case studies. selected crm are commodities in croatia such as magnesium, bauxite and barite, with high geological potential, high economic value and reasonable exploration/exploitation opportunities. in contrast, graphite and rare earth elements have moderate to modest geological potential, whereas some other commodities such as borates and lithium are currently only at the level of indicative geological potential in croatia. this estimation is based on the overall geological knowledge on the selected commodity and includes reserve estimation (magnesium, bauxite and barite), resource estimation (graphite and rare earth elements) and potentiality estimation (lithium and boron). 2. magnesium magnesium is the 8th most abundant element in the earth’s crust with at 2.1 mass % and the third most abundant element in sea water at 0.13 mass %. there are over 60 mg­containing minerals listed (koegl et al., 2006), many of which are rock­ forming minerals such as olivine, pyroxene, amphibole and the chlorite group of minerals, as well as widespread magne­ sium carbonates (magnesite, dolomite and magnesium calcite). commercially important minerals for the extraction of mag­ nesium are the carbonates; magnesite (mgco3; mg=28.8 wt%) and dolomite (camg(co3)2; mg=13.2 wt%, that serves both the crushed stone aggregate and chemical industries), whereas mg­rich olivine and serpentine are used for the refractory industries (table 1; koegl et al., 2006). magnesium has versatile applications in industries: automotive industry (48%), packaging applications (23%), construction industry (13%), desulphurisation of steel (12%), heavy transportation (air, marine, railway; 4%) as well as medical equipment, sport applications, electrochemical and organic chemistry applications, its importance has been widely acknowledged (grohol & veeh, 2023). this is why the european commission already listed magnesium as a critical raw material in its first communication in 2011, and it has remained on the list until the present day due to a lack of domestic production and growing demand (european commision communication 2011, 2014, 2017, 2020). during 2019, the world production of magnesium metal was 928 kt. the majority of magnesium is produced in china (89%) and 4% in the us, followed by russia, israel, kazakhstan, brazil and south korea. currently, there is no magnesium pro­ duction in the eu. however, eu industry annually consumes around 113 kt of magnesium (15% of the total annual world production), 97% of which is imported from china. croatia hosts high quantities of high­quality dolostone, currently mined for the crushed stone aggregate industry or carbonate material for industrial processing, as well as several saltpans producing reject brines enriched in magnesium. the aim of this manuscript is to: (1) investigate on the important properties of magnesium­bearing minerals and deposits (including secondary sources) as well as common mining and processing methods and applications; (2) provide a compre­ hensive overview on the magnesium­bearing deposits, occur­ ren ces and potentiality maps within the republic of croatia; (3) present a selected magnesium case­study; (4) propose economically justified mining and extraction technology, and potential applications for the selected case study. 2.1. commercial sources of magnesium magnesite, dolomite, brucite, bischofite, carnallite and olivine have been used or are considered to be raw materials for mg metal production along with brines, mg­sulphate­bearing brine-residue, fly ash, and serpentine-rich ultramafic rocks (including asbestos tailings). their magnesium content varies greatly (table 1). 2.1.1. primary magnesium sources primary minerals for extraction of magnesium are the carbonates magnesite (77% of chinese and a part of usa domestic production) and dolomite (27% of chinese domestic production, 100% of brazil and south korea and dominant part of usa domestic production), that jointly correspond to >90% of world magnesium production. evaporite minerals such as carnallite (russia, ukraine and israel), and bischofite (kazakhstan) are of secondary importance for magnesium production (<10% of the world magnesium production; grohol & veeh, 2023; usgs country reports, 2022). 2.1.1.1. evaporite rocks although it has low magnesium content (mg=8.8 wt%), carnallite is used for magnesium metal production. carnallite table 1. magnesium content (in wt%) in common raw materials (adopted after simandl, 2007; mahmud et al., 2022; international magnesium association, 2023). name chemical formula  mg content (wt%) primary source earth crust average 2.1 carnallite kmgcl3 × 6(h2o) 8.8 bischofite mgcl2x6h2o 12.0 dolomite camg(co3)2 13.2 talc mg3si4o10(oh)2 19.2 huntite mg3ca(co3)4 20.7 olivine (mg,fe)2sio4 25.4 hydromagnesite mg5(co3)4(oh)2 x 4h2o 26.0 serpentine mg3si2o5(oh)4 26.3 magnesite mgco3 28.8 brucite mg(oh)2 41.7 periclase (unstable) mgo 60.3 secondary source fly-ash variable max. 9.8 asbestos tailings variable 23-25 fluid source seawater average 0.1 desalination reject brine average 0.3 salt lakes brine average max. 9.0 g eologia c roatica 89borojević šoštarić et al.: croatian critical mineral commodity letters: magnesium is also major potassium source and is primarily used for manufacturing potassium fertilizers in a two­step process. the process begins with electrochemical production of elemental magnesium (mg) and solid sludge waste with a high k2o (≈ 43%) content, used in the second step to manufacture k2o rich fertilizers (sharma et al., 2018). magnesium from salts such as carnallite and bischofite is recovered using solution mining, starting with the injection of fresh, sometimes heated water in the deep subsurface evaporite structures (>1,100 m) containing potassium/magnesium salt layers which become saturated with kcl and mgcl2 (e.g., at veendam in the netherlands; velama et al., 2010). 2.1.1.2. carbonate rocks dolomite (mg=13.2 wt%), and to a lesser extent magnesite (mg=28.8 wt%) represent major raw materials for the production of magnesium metal using a thermal reduction process (carbothermic process; simandl et al., 2007). although huntite and hydro­magnesite have a higher mg content (20.7 and 26 wt%, respectively), their greatest potential currently appears in flame retardant applications (table 1; simandl et al., 2000). when exposed to the heat of a fire, those minerals decompose in an endothermic reaction, cooling down the flame and releasing carbon dioxide at the same time (hollingbery & hull, 2012). 2.1.1.3. ultramafic rocks extraction of magnesium from silicate minerals associated with ultramafic rocks such as olivine, serpentine or talc is under development. hansen & zander (2011) patented a method for the extraction of silica and magnesium from olivine using chemical and thermal treatments (ep 1 373 139 b1). lu & neelameggham (2021), conducted the first successful industrial demonstration, extracting magnesium from serpentinite via an aluminium­silicon thermal reduction line with an annual processing capacity of 21,000 tons. brucite has a very high magnesium content, a low level of impurities and low dehydration temperature (mg=41.7 wt%; the dehydration reaction of brucite to form periclase is ≈550 °c at 1 atm pressure; johnson & walker, 1993) making it highly suitable for the extraction of magnesium (simandl et al., 2007). currently, brucite is only used as a flame retardant. compared to carbonate flame retardants including huntite and hydro­magnesite, brucite does not contain co2; hence no emissions are related to the calcination process upon burning. periclase is a high­pressure mineral, rarely occurring in nature, and when exposed to weathering is transformed to brucite (dorfman et al., 2012). 2.1.2. secondary magnesium sources the global annual production of fly-ash is around 600 million tons. fly-ash is a fine-grained, powdered waste material formed in power plants as a product of the combustion of pulverized coal. its chemical composition is highly variable (mainly oxides sio2, al2o3, cao, fe2o3) and depends on the type of fuel burned (bituminous or sub­bituminous coal, lignite, wood and peat), however, some types are characterised by an increased magnesium content of up to 9.8 wt% (myllymäki et al., 2019). the first production of magnesium metal from fly-ash was expected in 2023 using a combination of patented hydrometallurgical extraction and thermal reduction process (larobe magnesium, 2024). 2.1.2.1. asbestos tailings asbestos tailings (serpentinite, amphibole) raised significant interest as a secondary mg­source due to their high magnesium content (average mg=15­18 wt%). several plants are already in operation in canada and europe using electrolytical or pyrometallurgical processes. leaching with sulfuric acid in the presence of fluorite powder is suggested recently as a more environmentally friendly process compared to conventional methods (liu et al., 2022). 2.1.2.2. magnesium from fluid sources after the desalination of seawater, a large quantity of reject brines is produced with higher salinity concentration than the feed­seawater which represents another important source of magnesium (mg=0.28 wt%). currently more than 15,900 desalination plants are in operation worldwide, with a total desalination capacity of about 95 million m3 per day (jones et al., 2019). 2.1.2.3. salt lakes brine salt lakes brine currently serve as a dominant source of lithium, accounting for 59% of lithium world reserves (chile, bolivia, argentina, and china; zhang et al., 2022). most brines contain a high mg/li ratio, where the mg content reaches up to 9 wt%. separation of lithium from magnesium using precipitation methods has been suggested, whereby lithium remains in solution and magnesium precipitates in the form of carbonate, aluminate or phosphate (zhang et al., 2022 and references therein). 2.2. deposit types (primary magnesium sources) 2.2.1. mg deposits in evaporite rocks marine evaporites are layered sedimentary rocks that in most cases chemically precipitate due to the evaporation of seawater in hot, arid areas where generally the amount of water lost by evaporation exceeds the total amount of water from rainfall and influx via rivers and streams (guilbert & park, 1986). after evaporation of a seawater column of 1000 m, 15­ 17 metres of beds form, starting with carbonates (0.6%; calcite, dolomite, magnesite, aragonite), sulphates (3.6%; gypsum and anhydrite), and chlorides (78.2% halite, followed by k, mg salts of 17.6%; sylvite, carnallite, epsomite, kainite) at the uppermost levels of the evaporation sequence. small amounts of borates, nitrates, and celestine will also form. if tectonically undisturbed, this hypothetical evaporite sequence will occur as well­bedded, with k­mg salts associated with the uppermost parts of the thick halite layers. the world’s largest k­mg bearing evaporite basins are (kogel et al., 2006; caputo, 2011; statistica, 2024): (1) middle devonian north american saskatchewan evaporite basin extending through western canada, toward usa montana and north dakota, with estimated reserves of over 1.1 billion tons, (2) permian zechstein basin extending mainly through germany, belarus and russia (for example the upper g eo lo gi a c ro at ic a 90 geologia croatica 78/1 kama basin in the perm region in russia), with estimated reserves of over 1.3 billion tons, and (3) permian­carboniferous amazon potash basin, comparable in size with the saskatchewan basin, with an estimated potential of 30 billion tonnes but mainly halite and sylvite (magnesium sulphates and salts occur subordinately). 2.2.2. mg deposits in carbonate rocks 2.2.2.1. dolomite dolomite is usually formed from calcite via process of diagenetic replacement called dolomitization. subordinately, dolomite can precipitate as a primary mineral from seawater or lake, or directly from hydrothermal or metamorphic fluids. dolomitization includes the replacement of calcium for magnesium in the carbonate structure under the influence of a mg-bearing fluid. the process usually includes evaporation of seawater in a sabkha environment, the reflux of seawater in shallow lagoons, the mixing of freshwater and hypersaline brine with seawater, basinal brines or with any other source of mg-rich fluid (warren, 2000). dolomitic rocks (dolostone) are composed of dolomite or mg­bearing calcite, or a mixture of both minerals together with calcite and some other terrigenous or evaporite minerals (warren, 2000). they are widely distributed throughout the world, and are of different geological ages. significant production of dolomite for mainly construction purposes exists in north america, china, russia and the eu (top dolomite suppliers, 2024). 2.2.2.2. magnesite the veitsch­type of sucrose and coarse­grained “sparry” magnesite deposit that forms monomineralic lenses within marine carbonate­platform sediments (limestone and dolomite) is the most common magnesite type (pohl, 1990). it exhibits many diagenetic features, and is commonly interbedded with dolomite, sometimes with limestone, pelitic and psammitic siliciclastics, including in some cases, magnesite pebbles from older formations. its origin is related to mg­rich brine circulation and linked to the dolomitization process. 2.2.3. mg deposits in ultramafic rocks 2.2.3.1. magnesite the kraubath­type of magnesite deposits consist of veins and stockwork of micro to crypto­crystalline magnesite hosted by ultramafic rocks, and is economically the most significant type (pohl, 1990). it is commonly found associated with serpen­ tinised ultramafic rocks of the tethyan ophiolites, or within stratified large mafic-ultramafic intrusions (pohl, 1990). magnesite veins can reach a thickness of 45 metres and strike for up to 4 kilometres, usually following regional fracture pat­ terns. magnesite appears as snow white, massive or brecciated, sometimes crypto-crystalline with a cauliflower-like nodular infill. when occurring as stockwork, the country rocks are pervasively altered. genetic models suggest that the mg­ source is the surrounding ultramafic rocks, that are mobilised via near­surface, low­temperature hydrothermal systems (per ascensum model) or via deeply circulating meteoric waters (per descendum model). the lacustrine variety of the kraubath­type is the bela stena type, associated with hydrothermal circulation of the mg-bearing solutions from nearby ultramafic terrains. upon discharging into lacustrine neogene basins, magnesite pre­ cipitates as cryptocrystalline or nodular aggregates within lake sediments (ilić, 1968; wilson & ebner, 2005). 2.2.3.2. olivine, serpentine, talc olivine and serpentine are major minerals constituting ultramafic rocks such as dunite (>90% of olivine), serpentinite (predominantly composed of serpentine) or peridotite (40­90% of olivine) and are widely distributed in the ophiolites of for example the alpine­himalayan belt, or associated with large layered mafic-ultramafic intrusions worldwide (bushweld great dyke of zimbabwe, stillwaters, mustox, duluth, skaegaard, penikat and portimo, kemi, munni­munni etc). talc is predominantly formed via hydrothermal meta­ morphism of mg­silicates (serpentine, pyroxene, amphibole, olivine), in the presence of carbon dioxide and water, and therefore is again associated with ultramafic rocks. talc can also be formed via skarn reaction including dolomite, silica and water and associated with skarn deposits. in both cases, the appearance of talc will be in the form of irregular lenses, veins and stockwork. 2.3. mining methods 2.3.1. solution mining of mg from evaporite rocks solution mining refers to the production of salt by pumping water into subterranean salt deposits, found in many parts of the world, dissolving the salts and pumping the brine to the surface for drying and further use (machovec, 1980). the mineral carnallite is deliquescent, with the ore absorbing moisture from the atmosphere. this tends to weaken the structural strength of the ore body, and renders it unsuitable for conventional mining but suitable for solution mining. raw magnesium chloride can be recovered using solution mining at a depth of 1500 to 2000 metres. one example is the nedmag mine near veendam in the netherlands where underground caverns are formed in stacked layers of bischofite, carnallite and halite. the salt layers consist largely of nacl but contain at least 35% magnesium chloride. recovery is implemented by injection of fresh water in the salt layer, which becomes saturated with magnesium. the carnallite and bischofite layers largely consist of the less soluble nacl, with interspersed magnesium salts (velema et al., 2010). 2.3.2. conventional mining methods both dolomite and magnesite are mined and concentrated by conventional mining methods including underground and open pit mining (kogel et al., 2006). in some cases mines can operate as both an underground and open pit mine at the same time. the mine in breitenau, austria owned by rhi magnesite operates a large underground mine but also an open pit (drnek & frömmer, 2008). the main factor for choosing between underground and open pit mining is constrained by the ore to cover­beds ratio. dolomite and magnesite are more often mined by open pit mining, and the https://arijco.com/top-dolomite-suppliers/ g eologia c roatica 91borojević šoštarić et al.: croatian critical mineral commodity letters: magnesium mining process usually includes drilling and blasting, loading, transporting, crushing, grinding, screening, stocking and transfer to the factory. the run­of­mine ore is rarely shipped or used in crude form. it is processed near the mine site to yield magnesia products. although the open pit mining method is more preferentially used in some mines, various underground mining methods are also in use. in cases where the magnesium ore deposits are located at significant depths, and the value of production covers the higher costs of underground exploitation, underground mining may be the most appropriate method. underground mining is more complex and expensive than open­pit mining. in the case of high­quality raw magnesite, for example the koutzi ug mine owned by grecian magnesite, a small scale, underground narrow vein mining method can be used. 2.4. extraction of magnesium for a long time, roughly half of the magnesium had been recovered from seawater, which remains a significant source of magnesium in some countries. however, after the magne­ sium seawater plant had been closed in the usa, china has been increasing its share in global production. today, the predominant magnesium resources are dolomite, magnesite, carnallite and brines. known mg extraction methods belong to either the thermal reduction or the electrolytic categories (simandl, 2007). thermal reduction methods (silicothermic, alumino ther­ mic and carbothermic) operate at high temperatures. the silicothermic process relies on the use of ferrosilicon to reduce magnesium oxide to a molten slag at temperatures between 1200­1600 °c. a reduced gas pressure above the slag produces magnesium vapour. this vapour is condensed at a location removed from the main furnace or in the low temperature zone of the converter. the ingots of condensed magnesium are then re-melted, refined and casted. the pidgeon, magnetherm and bolzano processes have all been successfully used in the past (aghion & golub, 2006). although a large number of technically proven electrolytic processes exist, commercial magnesium electrolysis is conducted most commonly in a chloride melt of mixed alkali metals at temperatures below 700 °c. the feed to the electrolysis process is either anhydrous magnesium chloride, kmgcl3 produced from the dehydration of carnallite, or partially dehydrated magnesium chloride. the later feed can be derived from a variety of raw materials including dolomite, magnesite, bischofite, serpentine group minerals, sea water or brines. a list of the different thermal, reduction and electrolytic, and extraction processes is shown in table 2 together with the name of the process, sources, feed preparation, reaction and temperature and pressure. the main differences between the electrolytic and thermal reduction processes in terms of energy type and consumption, capital investment and labour requirements are shown in table 3. table 3 shows that the thermal reduction processes are labour­intensive and energy­intensive, but the required capital investment is quite low. the pidgeon process is a thermal table 2. different thermal reduction, electrolytic and extraction processes (adopted after wulandari et al., 2010). process route sources feed preparation reaction temperature/pressure thermal reduction process silicothermic dolomite, fesi calcination; fesi making; pelleting mgo+cao+fesi= mg(g) + ca2sio4(s) + fe(s) t=1160 °c p=1.2 x10-4 atm carbothermic magnesite, carbon calcination; pelleting mgo+c = mg(g) + cog t=1700 °c p=1 atm magnetherm dolomite, bauxite fesi calcination; fesi making 2caomgo + (xfe)si+ nal203= 2caosio2 nal2o3+2mg+xfe t=1550 °c p=0.05 atm aluminothermic dolomite, al scrap calcination 4mgo(s) + 2al(s)= 3mg(g) + mgal2o4(s) t=1700 °c p=0.85 atm mintec dolomite, bauxite fesi, al scrap calcination 2caomgo + (xfe)si+ nal203= 2caosio2 nal2o3+2mg+xfe 4mgo(s) + 2al(s)= 3mg(g) + mgal2o4(s) t=1700 °c p=0.85 atm electrolytic dow process brine/sea water neutralization, purification, dehydration electrolytic mgcl2(1) ® mg(1)+ cl(2) anode: 2cl® cl2 + 2e cathode: mg2+ + 2e® mg t=700-800 °c p=1 atm am process magnesite mining, leaching with hcl, dehydratation ig farben process sea water/brine neutralisation, prilling, dehydration chlorynation table 3. difference between electrolytic and thermal reduction process (adopted after simandl, 2007). method electrolytic thermal reduction (pidgeon process) energy type hydro-electric, gas, oil coal, gas energy requirements (mwh/t of mg) 18-28 45-80 capital investments (usd/t of mg capacity) 10 000-18 000 ≤ 2000 manpower requirements x 5x g eo lo gi a c ro at ic a 92 geologia croatica 78/1 reduction process based on the silicothermic reduction of magnesium oxide. it is the oldest and simplest extraction process with high energy requirements, which is widely used in china, making china the world's largest supplier of mg, but also the world's largest polluter. 2.5. magnesium applications due to the fact that magnesium is the lightest structural metal, and due to its low density, it is significantly lighter than widely used aluminium and steel (mordike & ebert, 2002; inter national magnesium association, 2023). in most applications, magnesium is used in the form of mgo, particularly in the manufacturing of refractory products including crucibles, shapes and furnace linings. pure magne­ sium is traded at 99.8% mg or higher (british geological survey, 2004). the principal application of magnesium is in metallurgy for the production of light alloys. it is most frequently alloyed with al, or al, zn and mn, and it is competitive when weight reduction of the end products in required, as in the airplane and car industries, without compromising strength. in alloy applications for high­speed components, the addition of mg reduces the internal forces caused by vibrations. when mg is added to al alloy, it will be more easily rolled, extruded and welded. typically, 0.1 to 5 wt% is added to al alloys (for an overview refer to tan & ramakrishna, 2021). the international magnesium associa­ tion (ima; 2023) summarizes many contemporary applica­ tions of magnesium. in the last ten years or so, magnesium has been increasingly used in the automotive industry due to more restrictive fuel consumption regulations as well as requirements for better driving performance, which both impose usage of lighter materials for the production of various car components. indeed, many car manufactures have already replaced tra ditio­ nally used metals such as steel and aluminium with magnesium in the production of a number of car parts. usage of magnesium allows easier casting of larger components, resulting in a smaller number of joints, thus making assembly easier and more cost effective. with further development of alternative power plants, in particular for electric cars, magnesium consumption in the car industry is expected to increase. similarly, magnesium has been extensively introduced in the aerospace industry due to the reduction of mass without compromising structural strength, promoting better fuel efficiency and thus lowering operational costs. it is also used in aircraft jet engines as well as in some airplane interior components. spacecraft and missile production sees magnesium as a favourable material for the same reasons. an additional advantage of magnesium is its high resistance to temperature, and protection from short­wave electromagnetic radiation and high­energy particles. in metallurgical processing such as steel desulphurization, magnesium is used due to its affinity for sulphur. in the production of ductile cast­iron, magnesium is inevitable, and it plays the role of reducing agent in the production of metals including beryllium, zirconium, uranium and titanium. magnesium is also used in the fabrication of various anodes, e.g. sacrificial anodes for welding and anodes for the prevention of galvanic corrosion of steel. the latter is widely employed in the protection of pipelines and many household appliances (for instance, water heaters). magnesium has a vast application in the production of various electronic products, particularly in small portable devices, again due to its lightness and strength. in this respect, magnesium is incorporated in the housing of many cell phones, notebooks, cameras and similar devices. at the same time, it has favourable thermal properties enabling fast heat dissipation, but also it protects devices from electromagnetic interferences. in medicine, milk of magnesia [mg(oh)2] is used as an antacid and laxative. epsom salts, epsomite (mgso4×7h2o) is used for the treatment of minor skin abrasions. magnesium has also been also used as an orthopaedic biomaterial. it has a high compatibility with the human body, it is not toxic, and the density of magnesium alloys as well as some other physical properties are much more compatible with the bones compared to other materials used for the same purposes, e.g. for various body implants. if uncoated, it is biodegradable, and thus easier to handle in post­surgery treatments, but could be coated if a more permanent application of the implant is required. for recreational purposes, sports accessories and equip­ ment can also utilize magnesium. light weight and impact strength are appreciated in the production of golf clubs (sticks), tennis rackets and bicycle frames. other various applications include pyrotechnics (appro­ priate alloying with aluminium in the form of fine powders), in special­purpose batteries, and in the printing industry (wrought magnesium plates). magnesium carbonate (mgco3) is used for some paints and inks but is also added to table salt as an anti­caking additive. in the production of optical lenses mgf2 films are used to reduce glare and reflection. 3. potential magnesium sources in the republic of croatia the republic of croatia hosts two major sources (fig. 1) from which magnesium could be extracted: (1) primary dolomite deposits and occurrences, mainly used as a high­quality crushed stone aggregate and carbonate mineral raw material for industrial processing, and (2) secondary mg reject brine from the nin, pag and ston saltpans. two additional secondary sources of magnesium are not considered here: (1) mravinačka kava asbestos waste deposits produced by the salonite factory, located near solin, and (2) fly-ash deposits produced by the plomin thermal power plant, istria. asbestos waste from mravinačka kava contains primary olivine and serpentine fibrous minerals with >25 wt% of magne sium. however, the waste deposit was recently recultivated into a sports and recreation area of approx. 0.03 km2 under the jurisdiction of the croatian environmental protection and energy efficiency fund (eurco, 2024). the fly-ash deposit from the plomin thermal power plant in istria is not considered an important secondary source of magnesium. it seems that the fly-ash has a minor magnesium content (1.83.8 wt% for raša, istria coals; peco, 2018), and is currently under reclamation, following the waste management report (cukon, 2016). g eologia c roatica 93borojević šoštarić et al.: croatian critical mineral commodity letters: magnesium 3.1. primary magnesium resources – carbonate deposits (dolomite) regarding the geographical setting, in the republic of croatia, dolomite (dolostone) deposits and occurrences are most commonly found in the pannonian­peripannonian and mountain regions. within these two major regions, dolomite is present in four assembled and labelled subregions (fig. 1): središnja zavala (1), hrvatsko zagorje (2), banovina, kordun i karlovački krš (3), and the gorski kotar (4) subregions. the fifth subregion is požeština, distinguished from the others, and located in the central part of the pannonian­peripannonian region. dolostone in this subregion is related to the slavonian mountains. additional secondary sources of magnesium are situated along the coastal region (fig. 1). deposits and occurrences of early and late diagenetic dolo­ stone are associated with two, geodynamically different stratigraphic megaunits (vlahović et al., 2005): (1) the south tethyan megaplatform (stm) represented by the upper norian, rhaetian dolostone and lower jurassic limestone and dolostone, and (2) the adriatic carbonate platform (adcp) represented by thick layered middle jurassic limestone and dolostone, upper jurassic limestone and dolostone, kim merid gian–tithonian boundstones, upper jurassic to lower creta ceous layered and massive dolostone and lower to middle cretaceous dolostone and post­sedimentary, diagenetic breccia (fig. 2). 3.1.1. south tethyan megaplatform dolomite (stm) 3.1.1.1. upper norian, rhaetian dolostone, hauptdolomit the hauptdolomit (dolomia principale; upper norian, rhaetian, velić & vlahović, 2009) is a widespread, thick dolomite­bearing unit associated with the southern tethyan megaplatform, relics of which can be found throughout the figure 1. potential magnesium sources in the republic of croatia. g eo lo gi a c ro at ic a 94 geologia croatica 78/1 region (croatia, slovenia, bosnia, austria, hungary, southern italy etc.; (vlahović et al., 2005). in croatia, this unit is extensive through the pannonian–peripannonian and mountain region and covers an area of 74.35 km2. the carbonate upper triassic's development is characterized by the continuity of sedimentation with the middle triassic, resulting in a much greater thickness, exceeding 1000 m (velić & vlahović, 2009). nevertheless, the thickness of these sediments is not suitable for volumetric calculations of hauptdolomite at a given locality. the sediment thickness in ogk sfrj (ogk = osnovna geološka karta – basic geological map) data is determined through surface mapping and author interpretation, rather than through specific research methods such as drilling. consequently, this sediment thickness should not be used in the calculation of mineral resource volumes. therefore, in the assessment of potentials based on the ogk sfrj, it is more advisable to utilize the surface representations rather than volumes. the same principle applies to the other mentioned stratigraphic units. 3.1.1.2. lower jurassic limestone and dolostone lower jurassic limestone and dolostone have been discovered in almost all parts of the croatian karst. based on the prevalence and bilateral relationship between limestone and dolostone, it is possible to distinguish an alternation of limestone and dolomite in the lower part, a predominant representation of limestone in the middle part, and bioturbated limestone in the upper part. regarding dolomite, it is mostly of late diagenetic origin, but there are also instances of early diagenetic dolostone, although these are less common. in general, dolostone is much less represented in this unit when compared to limestone. the sediments of this unit are rich in fossils in the lower and middle figure 2. stratigraphic units hosting significant amounts of dolomite based on croatian geological survey (2009, 2024). legend: t2 2-3: upper norian, rhaetian dolostone, hauptdolomit; j1: lower jurassic limestone and dolostone; j2: thick layered middle jurassic limestone and dolostone; j3; upper jurassic limestone and dolostone; j2 2,3: kimmeridgian–tithonian boundstones; j3 3, k1 1-2: tithonian–valanginian layered and massive dolostone; k1 6, k2 1: albian–cenomanian dolostone and post-sedimentary, diagenetic breccia. white and red dots are dolomite deposits and occurrences. g eologia c roatica 95borojević šoštarić et al.: croatian critical mineral commodity letters: magnesium parts, while in the upper part, fossil remains are absent due to changes in palaeoenvironmental conditions (velić & vlahović, 2009). they are mostly found in the mountain region of the republic of croatia and cover an area of 92.67 km2. the thickness of this unit is approx. 400­500 m. 3.1.2. adriatic carbonate platform 3.1.2.1. middle jurassic limestone and dolostone middle jurassic limestone and dolostone are primarily associated with the areas where lower jurassic sediments are observed. the basic lithological characteristic of these sediments is the prevailing occurrence of thick­bedded limestone with thin layers and lenses of late­diagenetic dolostone. these strata are abundant in microfossil communities of foraminifera and calcareous algae (velić, 2005). the thickness of this unit is very similar to the thickness of the previous stratigraphic unit, but it covers a smaller area, approx. 76.12 km2. 3.1.2.2. upper jurassic limestone and dolostone the upper jurassic limestone and dolostone, among all the distinguished jurassic units on the adcp, exhibits the greatest areal extent. this unit is characterized by its facies diversity. the main lithological feature of this unit is the lateral alternation of different types of limestone with predominantly late-diagenetic dolostone. the dolostone occurs in the form of irregularly shaped lenses of various dimensions within the limestone or in bodies of greater thickness with a massive habit. consequently, lenses of non­dolomitized limestone are found within the dolostone. typically, such larger bodies and occurrences of dolostone are associated with more strongly tectonized areas and fault zones. stratigraphically, the highest (youngest) occurrence of dolostone has been identified in the youngest jurassic sediments (velić & vlahović, 2009). the thickness of this unit is approx. 700 m, and it covers an area of 139.57 km2. 3.1.2.3. kimmeridgian–tithonian boundstones kimmeridgian–tithonian boundstones denote the sediments formed in three types of reef environments. these sediments represent barrier reef, fore­reef, and patch­reefs environments. the predominant role in the lithology of this unit is played by the biogenic component, namely the abundance of fossil re mains. sediments formed in these conditions are partially aff ected by late­diagenetic dolomitization, resulting in the appea rance of light­gray, coarse­crystalline dolostone within the lime stone, often as irregular lenses of various dimensions (velić & vlahović, 2009). the thickness of this unit is variable, between 400­600 m, and it covers an area of 36.05 km2. 3.1.2.4. tithonian–valanginian layered and massive dolostone upper jurassic to lower cretaceous (tithonian–valanginian) layered and massive dolostones are located only on the island of korčula, where they form the core of the island. these are gray to dark gray late­diagenetic dolostones, appearing as layered or massive, with micro­ and macrocrystalline mosaic structures. within the dolostone, lenses of dolomitized limestone, dolomite breccias, and nodules of chert are noticeable. late­diagenetic dolomitization has obliterated almost all the primary com­ ponents, structures, and textures in these sediments. due to this, the stratigraphic position of these dolostones can only be determined indirectly based on their superpositional settings. the thickness of this unit is approx. 500 m (korolija et al., 1976, 1977). because it occurs only on the island of korčula it covers a relatively small area, approx. 1.67 km2. 3.1.2.5. albian–cenomanian dolostone and post-sedimentary, diagenetic breccia middle to upper cretaceous dolomite and post­sedimentary, diagenetic breccia. the transition between the lower and upper cretaceous in a significant part of the dinarides is characterized by late­diagenetic dolostone and/or alternation of limestone­dolomite breccias without recognizable fossil content. within the sediments of this unit, in the tectonically less disturbed areas, a gradual transition is clearly visible from thin­bedded, unevenly dolomitized albian limestone to late­ diagenetic dolostone and completely recrystallized limestone, occasionally with relics of early­diagenetic dolostone. a considerably greater challenge is posed in areas with a high prevalence of breccias, where boundaries with older or younger formations are unclear, often as a result of tectonic activity (vlahović et al., 2002). this unit is mostly found in the mountain and coastal region of the republic of croatia and covers an area of 33.72 km2. the thickness of this unit varies, between 600­800 m. 3.2. case study: stm đipalo-sinj the đipalo dolomite deposit near sinj is of particular importance to the republic of croatia due to its high mgo content and low level of impurities. the deposit is located within the stm dolostone and limestone of middle triassic age, overlying the lower triassic red, marly micaceous­shales and sandstones and marly limestone, and underlying the lower jurassic dark gray fossiliferous and oolitic limestone and dolostone. in 1975 exploration work was carried out with the aim of determining the reserves and quality of the dolomite in the đipalo deposit. petrographic characteristics of dolomite were examined in 54 samples, and they all showed similar to identical microstructural characteristics, i.e. the examined dolostones are actually aggregates of anhedral, rarely euhedral grains, of uniform size. the share of non­carbonate admixtures is visible only in traces (clay substance and limonite; gabrić & lukšić, 1997). chemical analyses showed that the composition of the dolostones is very uniform throughout the entire deposit, both at depth and laterally. the mean values of the analysed elements for the đipalo deposit are given in table 4. the content of mgo in dolomite exceeds 22 wt%, whereas the sum content of sio2, fe2o3 and al2o3 remains below 1 wt%. the presence of other harmful components in the table 4. average content of oxides and selected microelements for the đipalo deposit (in wt%; loi = loss of ignition). loi sio2 cao mgo al2o3 tio2 s p b na2o k2o 47.09 0.025 30.32 22.12 0.031 0.001 0.013 0.003 0.00 0.116 0.008 g eo lo gi a c ro at ic a 96 geologia croatica 78/1 dolomite is very low: potassium, sodium, titanium, phosphorus and sulphur are present in traces that are not an obstacle to any form of industrial processing. the total rock mass in the deposits represents a usable mineral raw material, therefore correction with accompanying coefficients is unnecessary. exploitation losses are about 5%. this is quite low when compared to data obtained from similar deposits (gabrić & lukšić, 1997). the quantities of dolomite reserves are shown in table 5. reserve classification is based on eastern european classification system, also known as “russian code” where reserves of a, b and c1 categories depend on the degree of geological knowledge (having 90, 80 and 70% reliability, respectively). 3.3. secondary magnesium resources – mg-rich, reject brine from saltpans annually, the croatian saltpans of nin, pag and ston produce around 20,000 t of sea salt. the majority of the salt is produced in the pag saltpan (around 18,000 tons), followed by the ston (0.8 tons) and nin saltpans (0.5 tons). halite generally precipitates when around 90% of the seawater evaporates and the concentrations of salt within seawater increase 10 times, i.e. from 3.5% to 35%. the halite will precipitate between 90 and 96% of the seawater evaporation, leaving the remaining 4% of the reject brine enriched in potassium and magnesium table 5. dolomite reserves of the đipalo deposit (gabrić & lukšić, 1997). category economic reserves (m3/t) exploitation reserves = (economic – exploitation losses) (m3/t) a 1,171,126 / 3,197,174 1,1120,570 / 3,3037,316 b 907,313 / 2,476,964 861,947 / 2,353,115 c1 224,031 /, 611,605 212,829 / 581,023 sum 2,302,470 /6,285,743 2,187,346 /5,971,454 figure 3. geological potentiality map of primary magnesium sources based on the geological map of the republic croatia at a scale of 1:300 000 (croatian geological survey, 2009). g eologia c roatica 97borojević šoštarić et al.: croatian critical mineral commodity letters: magnesium salts, close to the saturation point of kainite, carnallite and bischofite. considering that the average magnesium composition in the initial seawater is 1.262 ppm, in seawater reaching the halite saturation magnesium composition should be around 1.2%. the amount of secondary mg reject brine from the saltpans will depend on the salt production. using an average annual salt production rate of 20,000 t in croatia, the amount of discharged magnesium will be 2.38 t/annually. 4. discussion 4.1. geological potential of the primary magnesium sources croatian primary magnesium sources are categorized into three (3) groups according to their lithological, mineralogical, and chemical characteristics as outlined in section 3.1, as well as their prospectivity. these source groups include: 1) high­ potential magnesium sources, 2) medium­to­high magnesium potential sources, and 3) low­potential magnesium sources (fig. 3). only the t2 2­3, upper norian, rhaetian dolomite (hauptdolomit) can be included in the first (1) group. the medium to high potentiality group (group 2) comprises the following stratigraphic units; j1; lower jurassic limestone and dolostone, j2; thick­bedded middle jurassic limestone and dolostone, j3; upper jurassic limestone and dolostone, j2 2,3; kimmeridgian–tithonian boundstones, and j3 3, k1 1­2; tithonian–valanginian layer and massive dolostone. group three encompasses, specifically the cretaceous sediments, k1 6, k2 1; albian–cenomanian dolostones and the post­ sedimentary, diagenetic breccias. the republic of croatia has eight national parks (np), where the exploitation of mineral raw materials is banned. therefore, np areas must be excluded from the calculation of mineral raw materials potentiality (fig. 4). primary magnesium sources potentiality in suitability zones are grouped into the figure 4. calculated primary magnesium sources potentiality in suitability zones. g eo lo gi a c ro at ic a 98 geologia croatica 78/1 low potentiality (436 km2), and the medium to high potentiality categories in the suitability zones (5,285 km2) and into the high potentiality category in suitability zones (807 km2, fig. 4). total primary magnesium sources potentiality in the republic of croatia amounts to 6,528 km2. since this potential is based on geological data at a scale of 1:300,000, it is necessary to consider certain calculation deviations. the detailed primary magnesium sources potentiality will be determined for the area of a higher potential shown on a larger scale. the future croatian national exploration programme will include magnesium as one of the commodities with high potential in the republic of croatia. this exploration programme will be primarily focused on the high potentiality of the upper norian, rhaetian dolomite (hauptdolomit). 4.2. economic assessment of the đipalo dolomite deposit 4.2.1. potential uses considering the high mgo content >22 wt%; (gabrić & lukšić, 1997), the đipalo dolomite can be used in the refractory material industry, as an agent of fusion or “flux” in ferrous metallurgy; in the production of cement; in the glass and ceramics industry; in the production of paper etc. research performed by jakić et al. (2016) showed that chemical, mineralogical and granulometric characteristics of the dolomitic lime extracted by calcination of the đipalo dolomite can be used as a reagent for the precipitation of magnesium hydroxide from seawater. 4.2.2. suggested mining and extraction methods the average chemical content of dolomite from the đipalo depo sit (30.32% cao and 22.12% mgo) is close to the stoichio­ metric value (gabrić & lukšić, 1997). the need to refine/ process the mineral raw material is therefore completely re­ dundant. taking into consideration the final use of the dolomite as a material for industrial processing, the technological pro­ cess will necessarily involve the steps of blasting, crushing, and pulverizing the dolomite. although production of magne­ sium from dolomite is associated with high environmental impacts and is mainly conducted in china, it is important to note that dolomite is suitable for magnesium production using the pidgeon process. dolomite consumption in the pidegon process depends on the content of mg, the purity of the raw material and ranges between 10 and 15 kg of dolomite per kg of mg metal produced (ramakrishnan & koltun, 2004). 4.2.3. economic assessment currently, only the quantities of mineral reserves are known, and a mining project has not been developed. as part of the mining project, a detailed description of the exploitation­ method should be included together with a techno­economic analysis, including the costs of exploitation. in the absence of such data, the approximate extraction price for similar dolomite deposits in the republic of croatia was taken into consideration in our calculations (galić & pavelić, 2020; table 6). the mining costs for 1 m3 of dolomite after blasting are about 3 €/m3. after blasting, the volume of dolomite increases by about 40% compared to the in situ volume of the deposit, which means that the total volume of dolomite extracted is about 3 000 000 m3. the mining costs for 1 t of dolomite are about 1.51 €/t (using an average density of dolostone as 2.73 kg/m3). the minimum market value of the dolomite after blasting is about 3.33 €/m3 or 1.67 €/t, which means that the value of the deposit is about 10 m€. the value of the deposit increases with the refining and processing of the mineral raw material, which varies depending on the end use of the dolomite. table 7 shows the number of different products that can be achieved with various forms of dolomite processing. it is difficult to estimate the profit because the costs of the individual processes are currently unknown. although the quantities of dolomite products from construction raw material to pure magnesium are significantly reduced, the market price rises considerably. the prices of products are approx. 1.7 €/t for construction raw material; 10 €/t for crushed stone aggregate; 100 €/t for high­quality dolomite and 2,250 €/t for 99.0%­purity magnesium metal. considering the high atmospheric emissions and the high­ energy consumption in magnesium production, it is unlikely that the production of magnesium from dolomite will take place on eu territory. the categories for the global impact of different mg production processes range between 1.04 and 4.20 (104 kg co2 eq.) or between 20.74 and 298.49 (kg so2 eq.) per ton of mg ingot (cherubini et al., 2008). however, there are examples of existing mg production plants in serbia or planned production plants in bosnia and herzegovina (mfe magnesium for europe, 2024). table 6. the average costs of exploitation of 1 m3 of technical-building stone after galić & pavelić (2020). no costs €/m3 1 costs of exploration works and preparation of the topographic base 0.05 2 costs of assessing the quality of mineral raw materials 0.02 3 costs of managing property-legal relations for land parcels 0.05 4 costs of technical documentation and acts 0.05 5 exploitation fee costs 0.18 6 transport infrastructure costs 0.27 7 costs of purchasing machines and equipment for excavation 0.48 8 maintenance costs of digging machines and equipment 0.27 9 material and energy costs 0.72 10 excavation labour costs 0.68 11 costs of occupational safety, environmental and nature protection, utility fees 0.13 12 costs of remediation of the exploitation field 0.07 sum 2.95 table 7. quantity of different dolomite products from đipalo deposits. type of product quantity (t) processing efficiency (%) construction raw material 5 971 454 100 stone aggregate 5 374 308 90 refractory industry (roasted) 3 164 870 53 magnesium (99.0%) 590 000 below 10 g eologia c roatica 99borojević šoštarić et al.: croatian critical mineral commodity letters: magnesium 5. conclusion the important properties of magnesium bearing minerals and deposits (including secondary sources) as well as the common mining and processing methods and applications are: • primary sources of magnesium are evaporite rocks (carnallite, bischofite) carbonate rocks (dolomite, magnesite) and ultramafic rocks (olivine serpentinite, talc), and to some extent also brucite and periclase. • mg deposits in evaporite rocks are located in the uppermost levels of the evaporite sequence, associated with potassium and linked to the last stage of seawater evaporation, following the precipitation of sodium­ chloride (<90­96% of evaporation), • mg deposits in carbonate rocks are: (1) dolomitic rocks, usually created from calcite via process of dolomitization under the influence of mg-rich fluids, related to a sabkha environment, shallow lagoons or basinal brines, and (2) magnesite that forms monomineralic lenses within marine carbonate­platform sediments, • mg deposits in ultramafic rocks are: (1) the kraubathtype of veins and stockworks of micro to crypto­crystal­ line magnesite; (2) the bela stena type, a lacustrine variety associated with hydrothermal circulation of the mg-bearing solutions from nearby ultramafic terrains; (3) olivine and serpentine, major minerals constituting ultramafic rocks (dunite, serpentinite) within ophiolite belts or within layered mafic-ultramafic intrusions, (4) talc related to hydrothermal metamorphism of mg­ silicates. • secondary sources of magnesium are fly-ash and asbestos tailings. • significant quantities of magnesium can be found in the reject brines after desalinization or evaporation of the seawater and salt lake brines. • commercially important minerals for the extraction of magnesium are carbonates (magnesite and dolomite) for the crushed stone aggregate and chemical industry, whereas mg­ rich olivine and serpentine are used for refractory industries. • solution­mining is recommended for the extraction of mg from evaporite rocks (pumping water into subterranean salt deposits, dissolving the salts and pumping the brine to the surface), where dolomite and magnesite are mined and concentrated also by conventional mining methods including underground and open pit mining. • magnesium is extracted via thermal reduction methods (silicothermic, aluminothermic and carbothermic) operating at high temperatures or recovered from seawater. • metallic magnesium has applications in the automotive industry, packaging applications, the construction industry, steel production, heavy transportation, medical equipment, sport applications, electrochemical and organic chemistry. the magnesium sources within the republic of croatia: • primary dolostone deposits and occurrences are mainly used as high­quality crushed stone aggregates and carbonate mineral raw materials for industrial processing, and not for production of metallic magnesium. • secondary mg reject brine from the nin, pag and ston saltpans remains unrecognised as a potential source of mg, although discharged magnesium is about 2.38 t/annum. • geologically, primary dolostone deposits are grouped to stm (upper triassic to lower jurassic) and adcp (jurassic to middle cretaceous) groups. • stm deposits are considered as high­potential magnesium sources, whereas adcp deposits belong to medium­to­high (jurassic) and low­potential (cretaceous) magnesium sources. • at a scale of 1:300,000, the overall geological potential of primary magnesium sources has been calculated. according to this calculation, in the republic of croatia, there are 807 km² of high potentiality geological strata (stm hauptdolomite), 5285 km² of medium to high potentiality, and 436 km² of low potentiality within areas where exploitation is not prohibited. however, additional restrictions arising from the three levels of spatial planning must also be considered. • based on the presented analysis, a croatian national exploration programme will develop new magnesium case­studies. magnesium case­study (an example): • the đipalo dolostone deposit near sinj (stm dolostone; exploitation reserves of 5.9 mt) shows high­purity dolostone with mgo > 22 wt%. the sum content of sio2, fe2o3 and al2o3 is below 1 wt%. • extraction processes include conventional mining methods of open­cast operation, blasting, crushing, and pulverizing. • the material can be used in the refractory industry, ferrous metallurgy, production of cement, glass, ceramics, paper or for magnesium metal production. • the value of the products increases in order from: construction raw material < crushed stone aggregate < refractory (roasted) dolostone < 99.0% pure metallic magnesium (more than 2,000 times). • in the case of production of magnesium metal, dolomite consumption is estimated as 10 to 15 t of dolostone per 1 t of mg produced, depending on the technological process. • co2 emissions and energy consumption of all analysed metallurgical processes remain high. references aghion, e. & golub, g. (2006): production technologies of magnesium.– magnesium technology: metallurgy, design data, applications, 29–62. https://doi.org/10.1007/3­540­30812­1 caputo, m.v. (2011): amazon basin potash perspectives.– in: 45 congresso brasileiro de geologia. belém, pará. https://doi.org/10.13140/rg.2.2. 11187.63522 cherubini, f., raugei, m. & ulgiati, s. (2008): lca of magnesium production: technological overview and worldwide estimation of envi­ ronmental burdens.– resources, conservation and recycling, 52/8–9, 1093–1100. https://doi.org/10.1016/j.resconrec.2008.05.001 croatian geological survey (2009): geological map of republic of croatia, m 1:300.000.– croatian geological survey, zagreb. dorfman, s.m., prakapenka, v.b. & meng, y. (2012): intercom­ parision of pressure 410 standards (au, pt, mo, mgo, nacl and ne) to 2.5 mbar.– journal of geophysical research, 117, b08210, 1–5. https:// doi.org/10.1029/2012jb009292 drnek, t. & frömmer, t. (2008): developments, challenges and trends in austrian magnesite mining.– gospodarka surowcami mineralnymi, 24/4­3, 257–266. g eo lo gi a c ro at ic a 100 geologia croatica 78/1 european commission communication (2011): communication from the commission to the european parliament, the council, the european economic and social committee and the committee of the regions – tackling the challenges in commodity markets and on raw materials.– brussels, 2.2.2011, com(2011) 25 final. european commission communication (2014): communication from the commission to the european parliament, the council, the european economic and social committee and the committee of the regions – on the review of the list of critical raw materials for the eu and the implementation of the raw materials initiative.– brussels, 26.5.2014, com(2014) 297 final. european commission communication (2017): communication from the commission to the european parliament, the council, the european economic and social committee and the committee of the regions.– brussels, 13.9.2017, com(2017) 490 final. european commission communication (2020): communication from the commission to the european parliament, the council, the european economic and social committee and the committee of the regions – critical raw materials resilience: charting a path towards greater security and sustainability.– brussels, 3.9.2020, com(2020) 474 final. gabrić, a. & lukšić, b. (1997): elaborat o rezervama i kakvoći dolomi­ ta, karbonatne sirovine za industrijsku preradu u ležistu,"đipalo" kod sinja [in croatian].– unpubl. report, croatian geological survey, zagreb, 31 p. galić, i. & pavelić, d. (2020): elaborat o rezervama tehničko-građevnog kamena na eksploatacijskom polju "pregrada ii" peta obnova [in croa­ tian].– unpubl. report, university of zagreb, faculty of mining, geol­ ogy and petroleum engineering, zagreb. grohol, m. & veeh, c. (2023): study on the critical raw materials for the eu 2023 – final report.– european commission: directorate­general for internal market, industry, entrepreneurship and smes, 158 p. https:// doi.org/10.2873/725585 guilbert, j.m. & park, c.f. (1986): the geology of ore deposits.– w.h. freeman and company, new york, 985 p. hansen, t. & zander, b. (2011): extraction of silica and magnesium compounds from olivine.– european patent specification ep 1 373 139 b1, bulletin, 2011/34, 1–5. hollingbery, l.a. & hull, t.r. (2012): the thermal decomposition of natural mixtures of huntite and hydromagnesite.– thermochimica acta, 528, 54–52. http://doi.org/10.1016/j.tca.2011.11.002 ilić, m. (1968): problems of the genesis and genetic classification of mag­ nesite deposits.– geologische rundschau, 79, 291–299. jakić, j., labor, m. & martinac, v. (2016): characterization of dolo­ mitic lime as the base reagent for precipitation of mg(oh)2 from seawa­ ter.– chemical and biochemical engineering quarterly 30/3, 373–379. http://doi.org/10.15255/cabeq.2015.2325 johnson, m.c. & walker, d. (1993): brucite [mg(oh)2] dehydration and the molar volume of h2o to 15 gpa.– american mineralogist, 78, 271–284. jones, e., qadir, m., van vliet, m.t.h., smakhtin, v. & kang, s. (2019): the state of desalination and brine production: a global out­ look.– science of the total environment, 657, 1343–1356. http://doi. org/10.1016/j.scitotenv.2018.12.076 kogel, j.e., trivedi, n.c., barker, j.m. & krukowski, s.t. (2006): industrial minerals & rocks: commodities, markets, and uses.– soci­ ety for mining, metallurgy, and exploration, 7th edition, 1565 p. korolija, b., borović, i., grimani, i. & marinčić, s. (1976): os­ novna geološka karta sfrj 1:100 000, list korčula l33-47 [basic geological map of sfry 1:100 000, korčula sheet – in croatian].– croatian geological survey, zagreb (1967­1968); geological survey gemini, be­ ograd. korolija, b., borović, i., grimani, i., marinčić, s., jagačić, n., magaš, n. & milanović, m. (1977): osnovna geološka karta sfrj 1:100 000, tumač za list korčula l33-47 [basic geological map of sfry 1:100 000, geology of the korčula sheet – in croatian].– croatian geological survey, zagreb (1968); geological survey gemini, belgra­ de, 1–53. liu, w., peng, x., liu, w., zhang, x. & wang, x. (2022): a cost-effec­ tive approach to recycle serpentine tailings: destruction of stable layered structure and solvent displacement crystallization.– international jour­ nal of mining science and technology, 32/3, 595–603. http://doi. org/10.1016/j.ijmst.2022.03.004 lu, h. & neelameggham, n.r. (2021): industrial practice of extracting magnesium from serpentine.– in: miller, v.m., maier, p., jor­ don, j.b., neelameggham, n.r. (eds): magnesium technology 2021. the minerals, metals & materials series, 153–159. http://doi. org/10.1007/978­3­030­65528­0_23 machovec, g. (1980): solar energy index.– elsevier science & technology books, 417–423. http://doi.org/10.1016/b978­0­08­023888­3.50018­x mahmud, n., fraga alvarez, d.v., ibrahim, m.h., el­naas, m.h. & esposito, d.v. (2022): magnesium recovery from desalina­ tion reject brine as pretreatment for membranelles electrolysis.– desali­ nation, 525, 1–13. http://doi.org/10.1016/j.desal.2021.115489 mordike, b.l. & ebert, t. (2001): magnesium properties — applications — potential.– materials science and engineering: a, 302/1, 37–45. http:// doi.org/10.1016/s0921­5093(00)01351­4 myllymäki, p., pesonen, j., romar, h., hu., t., tynjälä, p. & lassi, u. (2019): the use of caand mg-rich fly ash as a chemical pre­ cipitant in the simultaneous removal of nitrogen and phosphorus—recy­ cling and reuse.– recycling, 4/2, 1–14. http://doi.org/10.3390/recy­ cling4020014 peco, j. (2018): potential mobility of toxic elements from plomin soil con­ taminated with superhigh sulphur raša coal and ash [in croatian].– msc thesis, university of zagreb faculty of science, 1–77. pohl, w. (1990): genesis of magnesite deposits – models and trends.– ge­ ologische ruddschau, 79/2, 291–299. http://doi.org/10.1007/bf01830626 ramakrishnan, s. & koltun, p. (2004): global warming impact of the magnesium produced in china using the pidgeon process.– resourc­ es, conservation and recycling, 42/1, 49–64. http://doi.org/10.1016/j. resconrec.2004.02.003 sharma, l., brigaityte, o., honer, k., kalfaoglu, e., slink­ siene, r., streimikis, v., sviklas, a.m. & baltrusaitis, j. (2018): carnallite­derived solid waste as potassium (k) and magnesi­ um (mg) source in granulated compound npk fertilizers.– acs su­ stainable chemistry & engineering, 6/7, 9427–9433. http://doi.org/ 10.1021/acssuschemeng.8b01773 simandl, g.j., simandl, j., rotella, m., fournier, m. & debre­ cini, a. (2000): hydromagnesite in british columbia, canada.– en­ ergy, 61–64. simandl, g. j., schultes, h., simandl, j. & paradis, s. (2007): magnesium­raw materials, metal extraction and economics­global picture.– in: proceedings of the ninth biennial sga meeting, dublin 2007, 827–830. tan, j. & ramakrishna, s. (2021): applications of magnesium and its alloys: a review.– applied sciences, 11/6861, 1–16. http://doi.org/ 10.3390/app11156861 velić, i. (2005): benthic foraminifera assemblages and stratigraphic subdi­ vision of the middle jurassic in carst dinarides, adriatic carbonate plat­ form.– in: velić, i., vlahović, i., biondić, r. (eds): 3rd croatian geological congress, opatija, abstract book, croatian geological sur­ vey, zagreb, 159–160. velić, i. & vlahović, i. (2009): tumač geološke karte 1:300.000 [geology of the geological map of republic of croatia 1:300.000 – in croa­ tian].– croatian geological survey, zagreb, 1–147. vlahović, i., tišljar, j., fuček, l., oštrić, n., prtoljan, b., velić, i. & matičec, d. (2002): the origin and importance of the dolomite­limestone breccia between the lower and upper cretaceous deposits of the adriatic carbonate platform: an example from ćićarija mt. (istria, croatia).– geologia croatica, 55/1, 45–55. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and https://doi.org/10.2873/725585 https://doi.org/10.2873/725585 g eologia c roatica 101borojević šoštarić et al.: croatian critical mineral commodity letters: magnesium depositional dynamics.– palaeogeography, palaeoclimatology, palaeoe­ cology, 220, 333–360. http://doi.org/10.1016/j.palaeo.2005.01.011 warren, j. (2000): dolomite: occurrence, evolution and economically im­ portant associations.– earth­science reviews, 52/1–3, 1–81. http://doi. org/10.1016/10.1016/s0012­8252(00)00022­2 wilson, i. & ebner, f. (2005): a review of the worlds current and poten­ tial magnesite resources.– in: industrial minerals’ magmin event pro­ ceedings vienna, 41. zhang, y., xu, r., wang, l. & sun, w. (2022): separation of magnesium from lithium in salt­lake brine through struvite precipitation.– minerals engineering, 180, 107468. http://doi.org/10.1016/j.mineng.2022.107468 web sources: british geological survey (2004): commodity profile: magnesium. available on https://nora.nerc.ac.uk/id/eprint/534460. accessed: decem­ ber 10th, 2023. croatian geological survey (2024): map of mineral resources of the republic of croatia, croatian geological survey. available on: https://www.hgi­cgs.hr/karta­mineralnih­sirovina­republike­hrvatske­ 1200­000/. accessed on: december 10th, 2023. cukon, e. (2016): technical waste management report, te plomin [elaborat gospodarenja otpadom – in croatian]. available on: https://www. google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ah ukewjtmbf3gzyeaxwjzgihhtsaapoqfnoecbaqaq&url=https% 3a%2f%2fwww.istra-istria.hr%2fmedia%2ffiler_ public%2f9e%2f34%2f9e34212e­0fa3­4403­aeba­ 9d724d713be2%2f161107_elaborat_plomin.pdf&usg=aovvaw0unro1­ vcrk­lkwziky1ea&opi=89978449. accessed: december 10th, 2023. eurco (2024): available on: https://eurco.hr/sanacija­odlagalista­azbesta­ mravinacka­kava. accessed on: december 10th, 2023. international magnesium association (2023): magnesium applications. available on: https://www.intlmag.org/page/mg_applica­ tions_ima. accessed: november 17th, 2023. larobe magnesium (2024): available on: https://www.latrobemagne­ sium.com/. accessed on: december 10th, 2023. mfe magnesium for europe (2024): available on: https://www. mfe­europe.com/. accessed on: december 10th, 2023. statistica (2024): available on: https://www.statista.com/statistics/ 604174/distribution­of­potash­reserves­worldwide­by­select­country/. accessed on: december 10th, 2023. top dolomite suppliers (2024): available on: https://arijco.com/ top­dolomite­suppliers/. accessed on: december 10th, 2023. usgs country reports (2022): annual commodity reports: magne­ sium. available on: https://www.google.com/url?sa=t&rct=j&q=&esrc =s&source=web&cd=&ved=2ahukewiv_akwizyeaxvo9gihheogb s8qfnoecbiqaq&url=https%3a%2f%2fpubs.usgs.gov%2fperiodic als%2fmcs2022%2fmcs2022­magnesium­metal. pdf&usg=aovvaw 2iu9fcs_ebka_7ls4x2coj&opi=89978449. accessed on: december 10th, 2023. velema, w.r., bruining, h., bullen, j.g. & visser, j. (2010): na­ tural convection effects on magnesium solution mining.– available on: https://repository.tudelft.nl/islandora/object/uuid%3aef37a766­88f6­ 4291­a625­896e4127508a. accessed on: december 10th, 2023. wulandari, w., brooks, g.a., rhamdhani, m.a. & monaghan, b.j. (2010): magnesium: current and alternative production routes.– in: proceedings of the chemeca 2010, adelaide, australia, 11 p. available on: https://www.researchgate.net/publication/258278648_magnesium_ current_and_alternative_production_routes#fulltextfilecontent. accessed on: december 10th, 2023. 2022 | 75/1 | 115–128 | 9 figs. | 1 tab. | 2 pls. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society the radiolarian age and petrographic composition of a block of the lower jurassic volcaniclastic breccia and chert of the mamonia complex, sw cyprus nikita bragin1, galina ledneva1, liubov bragina1, efthymios tsiolakis2, vasilis symeou2 and nikolaos papadimitriou2 1geological institute of russian academy of sciences, moscow, 119017, russia, (*corresponding author: bragin.n@mail.ru) 2cyprus geological survey department p.o.box 24543, 1301 lefkosia, cyprus doi: 10.4154/gc.2022.07 abstract an exceptional exposure of volcaniclastic breccia intercalated with radiolarian cherts and limestones was studied which constitutes a unique block within the upper cretaceous mamonia mélange in the akamas peninsula of southwestern cyprus. this breccia, represents the lower part of the sedimentary cover of the upper triassic phasoula formation volcanics. the breccia mainly consists of clasts of metabasalts, diabases, metagabbros, hyaloclastites and quartz-albite-chlorite-epidote aggregates, which have been metamorphosed at greenschist facies, and subordinate siltstones. the thin-bedded cherts intercalated between breccia levels, yielded radiolarian assemblages, which indicate an early jurassic age (sinemurian to pliensbachian) for the sequence. 1. introduction the geology of southwestern cyprus is characterized by extensive occurrences of mesozoic allochthonous rock assemblages that were grouped together as the mamonia complex (gass, 1960; lapierre, 1975; robertson & woodcock, 1979; swarbrick & robertson, 1980; malpas et al., 1992). the mamonia complex is divided in two major sub-groups, the ayios photios group and the dhiarizos group, including extensive zones of tectonic mélange known as the mamonia mélange (fig. 1). the ayios photios group (swarbrick & robertson, 1980) consists of upper triassic to upper cretaceous sedimentary units (bragin & krylov, 1996; 1999; bragin et al., 2000; bragina & bragin, 2016), while the dhiarizos group (swarbrick & robertson, 1980) is composed of upper triassic to lower cretaceous basic volcanic rocks and their sedimentary cover. the mamonia mélange consists of a sedimentary matrix of highly tectonized siltstones and mudstones of the ayios photios group, mixed with different-sized blocks from various lithologies of the mamonia complex and to a lesser extent from the troodos ophiolite (geological survey department of cyprus, 2008; 2015). the age determination of the mesozoic sedimentary sequences of the mamonia complex is estimated from the presence of radiolarian chert and cherty mudstone layers within these deposits, indicating that the radiolarian biostratigraphy is of significant importance for the dating of these deep-water lithologies, which lack other macrofossils or foraminifers. this article presents new petrographic and palaeontological data from a sedimentary-volcaniclastic breccia block that presumably represents the lower part of the sedimentary cover of the dhiarizos group. this work represents the first time that this type of lower mesozoic sedimentary-volcaniclastic breccia, of southwestern cyprus, is studied from a micropalaeontological/biostratigraphical perspective. 2. geological setting two main mesozoic rock complexes are widespread in southwestern cyprus: the troodos ophiolite complex and the mamonia complex (fig. 2a). both are allochthonous and form systems of nappes, the relationship between them is strictly tectonic. the mesozoic complexes of cyprus reflect the history of the southern branch of neotethys. the mamonia complex represents the upper triassic to cretaceous deposits and upper triassic volcanics of the northern margin of gondwana, whereas the troodos complex constitute cretaceous oceanic formations. both complexes became juxtaposed in the late cretaceous with the development of the nappe system with chaotic assemblages (mélanges and olistostromes). the troodos ophiolite complex is a fully developed fragment of oceanic lithosphere that consists of lithologies ranging from upper mantle harzburgites to pillow lavas, overlain by umbers (hydrothermal sediments) with radiolarian cherts of the upper turonian to uppermost santonian perapedhi formation (wilson, 1959; swarbrick & robertson, 1980; blome & irwin, 1985; bragina & bragin, 1996; bragina, 2012; 2016). the latter are locally capped by a sedimentary sequence consisting of campanian to middle maastrichtian bentonitic clays and volcaniclastic sandstones and siltstones of the kannaviou formation (robertson & hudson, 1974; robertson, 1977). the mesozoic lithologies of the mamonia complex are mainly grouped into the ayios photios group (sedimentary) and the dhiarizos group (volcano-sedimentary), (robertson & woodcock, 1979; swarbrick & robertson, 1980), which are subdivided into a number of sub-units (fig. 1). the ayios photios group consists of the following sub-units: the vlampouros formation (upper triassic siliciclastics and micritic limestones with minor chert interlayers) (swarbrick & robertson, 1980; bragin & krylov, 1996; torley & robertson, 2018) and the episkopi formation (middle jurassic to article history: received june 02, 2021. revised manuscript accepted november 10, 2021 available online february 22, 2022 keywords: sedimentary-volcaniclastic breccia, metavolcanics, lower jurassic, radiolaria, cyprus g eo lo gi a c ro at ic a 116 geologia croatica 75/1 middle cretaceous, albian–turonian, alternating layers of cherts, mudstones, limestones, sandstones, siltstones and clays) (swarbrick & robertson, 1980; bragin & krylov, 1999; bragin et al., 2000). the thick lower cretaceous sandstones within the episkopi formation are referred to as the akamas member or the akamas sandstone (swarbrick & robertson, 1980). several authors in previous studies have included within this group another sub-unit, referred to as the marona formation to describe blocks of upper triassic hemipelagic limestones (swarbrick & robertson, 1980; torley & robertson, 2018). the dhiarizos group consists of the following sub-units: the phasoula formation (upper triassic basic volcanics with interlayers of limestones and cherts) (swarbrick & robertson, 1980; bragin, 2007; 2010), the loutra tis aphroditis formation (upper triassic lava breccias and volcaniclastic breccias with interlayers of volcaniclastic siltstones and radiolarian mudstones) (swarbrick & robertson, 1980), the petra tou romiou formation (detached blocks of upper triassic reefal limestones) (henson et al., 1949; swarbrick & robertson, 1980; martini et al., 2009), and the mavrokolympos formation (jurassic to cretaceous alternating layers of limestones, cherts, mudstones, siltstones and calcilutites) (swarbrick & robertson, 1980). the sedimentary interlayers within and above the phasoula and loutra tis aphroditis formations are referred to as the kholetria member and are represented by chert-limestone alternations (swarbrick & robertson, 1980). furthermore, the greenschistto amphibolite-facies metamorphic rocks are termed the ayia varvara formation (metasediments and metavolcanics of various dhiarizos lithologies, metamorphosed during the cretaceous) (malpas et al., 1992; chan et al., 2007; 2008). for the purposes of this study, field work was conducted in the southwestern part of the akamas peninsula (fig. 2). this area is characterized by the extensive distribution of the ayios photios group lithologies and the mamonia mélange. furthermore, sevefigure 1. generalized chart of the stratigraphy of the mamonia complex. the grey area shows the kholetria member within and above the phasoula formation. for other lithologies and references see text. figure 2. a – position of the study area in western cyprus. b – generalized geological map of the area east of lara bay (akamas peninsula, cyprus) (geological survey department of cyprus, 2015). g eologia c roatica 117bragin et al.: the radiolarian age and petrographic composition of a block of the lower jurassic volcaniclastic breccia and chert of the mamonia ... ral big blocks of the dhiarizos group (mainly the phasoula formation) are also observed within the mamonia mélange. these blocks are mainly composed of basic volcanics commonly with interbeds of limestone and radiolarian chert. one of these blocks is composed of sedimentary-volcaniclastic breccia consisting mainly of fragments of basalts, diabases and gabbro, with interlayers of limestones and cherts that yield abundant radiolarian assemblages. this roughly rounded block is located 2.5 km east-northeast of the northern lara bay (fig. 2) and has an extent of 270 x 200 m, with an elongated axis along a sw – ne direction (fig. 3, fig. 4a, b). the studied breccia block is in tectonic contact with the surrounding matrix of the mamonia mélange, that yields numerous small blocks of lower cretaceous akamas sandstone of the episkopi formation (swarbrick & robertson, 1980) (fig. 4c), upper triassic limestones of the petra tou romiou formation or the kholetria member (swarbrick & robertson, 1980), as well as basic volcanics of the upper triassic phasoula formation. the matrix of the mélange consists of reddish-grey to brownish-grey mudstones and siltstones. furthermore, another, smaller block of similar breccia was identified near the nw boundary of the studied breccia block (fig. 3, sampling location 18-19). from the detailed survey of the large breccia block, from the northwestern boundary (point 18-18, coordinates 34⁰ 58’ 22,4’’ n, 32⁰ 20’ 13,4’’ e) towards its southern edge (point 18-15, coordinates 34⁰ 58’ 17,5’’ n, 32⁰ 20’ 19,9’’ e) (fig. 3, 4, 5, 6), various individual units of the block were recognized and described: 1. greenish-grey hard cemented breccia mainly consisting of small (3-5 up to 15-20 cm in size) diabase and subordinate metagabbro clasts in a coarse-grained to gravelly matrix of the same composition. the thickness of the unit is 50 m. 2. greenish-grey and reddish-brown hard cemented breccia of metabasalt, diabase and metagabbro clasts with rare small fragments of red recrystallized limestone in a coarse-grained to gravelly matrix of metabasalt, diabase and metagabbro. lenses (1-2 m thick) of breccia within a pinkish matrix of highly brecciated limestone, occur in the upper part of the unit. the thickness of the unit is 100 m. 3. pink to greenish-brown hard cemented breccia of diabase and metabasalt clasts within a matrix of highly brecciated pink to white limestone (fig. 4f). the thickness of the unit is 4 m. 4. greenish-grey hard cemented breccia with lenses (1,5 m thick) of breccia within a matrix of highly brecciated pink to white limestone (fig. 4e). the thickness of the unit is 20 m. 5. white to pink, hard, thin-bedded recrystallized limestones with calcite veins (fig. 5f). the thickness of the unit is 2 m. 6. greenish-grey hard cemented breccia consisting of metabasalt, diabase and metagabbro fragments and blocks (fig. 4g, h) in a coarse-grained to gravelly matrix of the same composition. the thickness of the unit is 5 m. 7. brick-red and crimson-red, thin-bedded radiolarian cherts (fig. 5d) with interbeds (0,5 – 1 m) of pink and white hard recrystallized limestones (fig. 5e). the thickness of the unit is 20 m. 8. greenish-grey to reddish-brown, hard cemented breccia consisting of diabase and metagabbro fragments and blocks as well as rare fragments of siltstones in a coarsegrained to gravelly matrix of the metabasalt, metagabbro and diabases. the thickness of the unit is 5 m. 9. brick-red, thin-bedded radiolarian cherts intercalated with red cherty mudstones. interbeds (up to 1 m) of darkfigure 3. detailed map of the block of diabase-gabbro breccia. a – matrix of the mamonia mélange; b – diabase-gabbro breccia; c – beds of limestone and radiolarian chert within the breccia; d – blocks of the petra tou romiou limestone; e – blocks of the akamas sandstone; f – blocks of basic volcanics; g – fault within a block of diabase-gabbro breccia; h – positions of sampling and studying points. g eo lo gi a c ro at ic a 118 geologia croatica 75/1 figure 4. volcaniclastic breccia of the akamas peninsula. outcrops of breccia. a – block of the breccia, view from the south; b – same block, view from the east; c – contact between the breccia (left) and the mamonia mélange (right, with scattered blocks of akamas sandstone); d – breccia composed of small diabase and metabasalt clasts in a volcaniclastic matrix (unit 10); e – breccia with carbonate (calcite) matrix (unit 4); f – breccia with well-developed carbonate matrix represented by pink micritic limestone (unit 3); g – block of metagabbro (unit 6); h – blocks of diabase (unit 6). g eologia c roatica 119bragin et al.: the radiolarian age and petrographic composition of a block of the lower jurassic volcaniclastic breccia and chert of the mamonia ... greenish-grey breccia with fragments of metabasalt and metagabbro and lenses of pink recrystallized brecciated limestone are observed in the middle part of this unit. the contact between the chert and breccia layers is clearly sedimentary (fig. 5a-c). the thickness of the unit is 5 m. 10. dark-greenish-grey hard cemented breccia composed of unsorted diabase and metabasalt fragments in a coarsegrained to gravelly matrix of the same composition (fig. 4d). the thickness of the unit is 6 m. it is herein assumed that this fragmentary section is the lower part of the sedimentary cover of the upper triassic volcanics of the dhiarizos group, which consists of breccia, while the upper part of the succession is characterized by the presence of limestone and radiolarian chert layers that become more and more abundant towards the top. 3. materials and methods twenty-five samples of various rock types including metavolcanics, limestones and cherts were collected during fieldwork in 2018 and 2019. the petrography of the acquired rock samples was studied in standard thin-sections using a light microscope olympus bs51. radiolarians were extracted from chert samples using diluted (5%) hydrofluoric acid (hf) for twelve (12) hours and the residues were rinsed with water and dried. the residues were studied using a light microscope lomo-mbs-10. the microfosfigure 5. volcaniclastic breccia of the akamas peninsula. outcrops of sedimentary units (chert and limestone) between breccia. a – red radiolarian cherts and white limestones in direct contact with breccia (units 9 and 10); b – sedimentary contact between breccia and radiolarian chert. small lense of breccia within radiolarian cherts (unit 9); c – radiolarian cherts, a fault is visible in the left side of the photograph (unit 9); d – radiolarian cherts and bed of limestone (unit 7); e – strongly brecciated white to pink limestone (unit 7); f – thin-bedded tectonized and brecciated pink to white limestone (unit 5). g eo lo gi a c ro at ic a 120 geologia croatica 75/1 sils were collected, mounted, studied in detail and photographed with scanning electron microscopes: tescan 2300 in the geological institute ras, moscow, and tescan vega-ii xmu in the palaeontological institute ras, moscow. thin sections and radiolarian assemblages are stored in the geological institute ras, moscow, russia. 4. petrography 4.1. breccia with carbonate matrix the breccia consists of metabasalt, diabase and metagabbro blocks and clasts that are irregularly shaped, sub-angular and poorly sorted. these rock fragments vary from a few centimetres to 10-15, rarely 20-30 cm in size. the matrix is represented by micritic limestone or recrystallized calcite. 4.1.1. breccia clasts metabasalts are represented by amygdaloidal aphyric, plagioclaseand clinopyroxene-plagioclase porphyric varieties (fig. 7a, b, 8a, b). phenocrysts of clinopyroxene are represented by short-prismatic crystals (0.4-0.9 mm) and are partly replaced by amphibole. phenocrysts of plagioclase are tabular and often elongated tabular zoned crystals (0.2 mm); plagioclase is completely altered pseudomorphs of albite, epidote group mineral and chlorite creating a very fine-grained aggregate. the groundmass exhibits hyalopilitic and intersertal textures. the intersertal groundmass is composed of altered plagioclase, altered pyroxene and opaque minerals; the hyalopilitic groundmass is composed of elongated, needle-shaped, often skeletal plagioclase and altered glass replaced by a black opaque substance. diabase (fig. 7c) is composed of pseudomorphs after the alteration of plagioclase and pyroxene crystals, fe-ti oxides, quartz and micrographic intergrowths of quartz with feldspar. plagioclase pseudomorphs are nearly euhedral in form, elongated tabular grains of a microcrystalline aggregate of epidote, colourless chlorite and albite in cores or rims. pyroxene pseudomorphs are nearly euhedral and anhedral grains, represented by light-green to colourless amphibole with tiny inclusions of titanite. fe-ti oxides, which are abundant in the rock, comprise euhedral crystals with lacy edges. minor quartz (<1%) and its intergrowths with feldspar (<1%) fill interstices. the rock texture is doleritic. 4.1.2. carbonate matrix the matrix is represented mainly by pink to white micritic limestone which is often strongly brecciated and cut by calcite veins (fig. 8a, b). this matrix yields small non-sorted clasts of metabasalts and chlorite (formed supposedly after volcanic glass). sometimes, the matrix is represented by highly recrystallized calcite. there is no visible layering of the matrix. rare epidote group minerals are present in the carbonate matrix between clasts (fig. 7b). 4.2. breccia with sandstone-gravel matrix this type of breccia is composed of metabasalt, diabase and metagabbro blocks, altered volcanic glass, quartz-albite-chlorite-epidote aggregates and rarely siltstone clasts. blocks and clasts are irregularly shaped, sub-rounded and poorly sorted rock fragments from predominantly few centimetres up to 20-30 cm in size. the matrix is represented by sandstone-gravel that has the same composition with the large (both rock and mineral debris) clasts. breccia clasts metabasalts and diabase are represented by the same lithologies as clasts of the breccia with carbonate matrix. metagabbro (fig. 7d) is composed of clinopyroxene, pseudomorphs after the alteration of plagioclase and an accessory opaque mineral. clinopyroxene is preserved only in relicts and is largely replaced by green to light-yellow amphibole with lamellae of an opaque mineral (<100 µm in size) and chlorite with interference in a blue colour. plagioclase pseudomorphs form euhedral tabular grains, composed of a microcrystalline aggregate of albite, an epidote group mineral and chlorite. the opaque mineral is anhedral. metagabbro is a fineto medium-grained rock exhibiting a primary hypidiomorphic-granular texture. some clasts exhibit no primary textures. intensively fractured clasts of presumably altered volcanic glass (fig. 7e) consist of pale-green and colourless chlorite with minor hydrogarnet and fineto medium-grained aggregates of quartz, albitite, epidote group mineral and chlorite which are produced from an unidentified rock. figure 6. stratigraphic column of volcaniclastic breccia with interbeds of limestones and cherts. a – breccia with volcaniclastic matrix; b – breccia with carbonate matrix; c – limestone; d – radiolarian chert; e – position of samples with radiolarians and their numbers. numbers of units according to the description are shown to the right of the column. g eologia c roatica 121bragin et al.: the radiolarian age and petrographic composition of a block of the lower jurassic volcaniclastic breccia and chert of the mamonia ... figure 7. clasts typical of breccia. a – plagioclase-pyroxene porphyric basalts with intersertal groundmass (sample 18-17-6, unit 4); b – clasts of amygdaloidal aphyric basalt with a hyalopilitic groundmass and chlorite presumably after volcanic glass in carbonate matrix (sample 18-17-3, unit 4); c – diabase (metadolerite), enriched by ore minerals (sample 18-16-2, unit 8); d – metagabbro with plagioclase replaced by albite, zoisite and chlorite, and with clinopyroxene replaced by amphibole (sample 18-20-2, unit 1); e – fractured clast of chlorite with minor hydrogarnet presumably after volcanic glass in sandstone matrix dominated by quartz and plagioclase (sample 18-15-2, unit 10); f – clasts of siltstone and aggregate of quartz, albite, epidote group mineral and chlorite (sample 18-15-3, unit 10); g – detail of siltstone clast, polarized light (sample 18-15-3, unit 10); h – detail of siltstone clast (sample 18-15-3, unit 10). g eo lo gi a c ro at ic a 122 geologia croatica 75/1 siltstone clasts (sample 18-15-2, unit 10, fig. 7f-h) are composed of quartz and feldspar (albite). the supporting matrix is composed of chlorite and an epidote group mineral. thin fractures are filled by carbonate minerals. sandstone-gravel matrix sandstone-gravel matrix is represented by the same lithologies as in the blocks and clasts. the matrix exhibits no layering or sorting. occasional veins of calcite are present. 4.3. limestone and radiolarian chert beds and lenses within the breccia succession limestones and radiolarian cherts form interbeds and lenses within the breccia. limestones are represented by micrites which are commonly brecciated, and sometimes contain recrystallized radiolarian remains. stylolites and fractures filled by calcite are common; these fractures are commonly confined to limestone clasts (fig. 8c, d). red radiolarian cherts usually yield abundant, moderately, to poorly preserved radiolarian assemblages. fractures are filled by quartz (fig. 8e, f). 5. radiolarian assemblage and age of breccia abundant radiolarians are present in the chert beds of the upper part of the studied section (plate 1, 2, localities 18-15 and 18-16). the systematic composition of the radiolarian assemblages refigure 8. sedimentary rocks intercalated with breccia. a – brecciated limestone with rare clasts of aphyric and plagioclase porphyry metabasalts, and chlorite supposedly after volcanic glass. fractures filled with calcite cut both matrix and clasts (sample 18-17-5, unit 4); b – limestone with clast of plagioclase porphyry metabasalt with intersertal groundmass (sample 18-17-5, unit 4); c, d – brecciated micritic limestones with relics of radiolarians (sample 18-15-1, unit 9); e – red radiolarian chert with moderately preserved radiolarians (sample 18-15-7, unit 9); f – dark-red radiolarian chert with abundant, moderately to poorly preserved radiolarians (sample 18-6-6, unit 7). g eologia c roatica 123bragin et al.: the radiolarian age and petrographic composition of a block of the lower jurassic volcaniclastic breccia and chert of the mamonia ... covered from units 7 and 9 (fig. 6) is similar (table 1). the presence of several characteristic taxa within the radiolarian assemblages is used to determine the age of the radiolarian cherts ( fig. 9). primary attention was given to well-preserved radiolarians determined to the species level useful for dating. taxa described in open nomenclature are of secondary importance. sample 18-15-6 this sample yielded an abundant and diverse assemblage that allowed successful dating (fig. 9, table 1). bagotum maudence pessagno & whalen is present in the upper sinemurian – lower toarcian of canada (pessagno & whalen, 1982; carter et al., 2010), in the lower toarcian of japan (yao, 1997), and in the upper pliensbachian of oman (bleichschmidt et al., 2004). the presence of this species in the upper sinemurian is documented on kunga island (haida gwaii) in the sinemurian part of the sandilands formation together with the ammonite tetraspidoceras sp. (see fig. 3 in (carter et al., 2010)). the range of species according to the present data is upper sinemurian – lower toarcian. beatricea argescens (cordey) is known from the pliensbachian of british columbia, canada (cordey, 1998; goričan et al., 2006) and from the lower jurassic of japan and new zealand (goričan et al., 2006). bipedis hannai whalen & carter, 1998 is known from the lower hettangian – lower sinemurian of canada (carter et al., 1998), from the lower sinemurian of the philippines (yeh & cheng, 1998) and from the hettangian – sinemurian of turkey (tekin, 2002). the known range of the species is hettangian – lower sinemurian, but it needs additional study because it is proven by macrofossils only in haida gwaii, british columbia, canada (carter et al., 1998). bipedis japonicus goričan et al., 2006 was firstly reported from the hettangian to the pliensbachian of japan (hori, 1990). it was documented later in the lower pliensbachian of canada (carter et al., 2010). due to the absence of macrofossils in the lower jurassic chert sequences of japan, we can state that the range is from the hettangian to pliensbachian under question. gorgansium gongyloideum (kishida & hisada) is a worldwide known species with a large stratigraphic range – from the rhaetian (upper triassic) to the middle toarcian (cifer et al., 2020; tekin et al., 2020). katroma ninstintsi carter is known from the pliensbachian of canada (carter et al., 1988; carter et al., 2010), the philippines (yeh & cheng, 1998), austria (gawlick et al., 2001; cifer et al., 2020), turkey (tekin, 2002), and eastern russia (bragin & bragina, 2017). pantanellium sixi whalen & carter, 1998 is known from the upper sinemurian of canada (carter et al., 1998). this species is known from only one region, and its stratigraphic range needs additional study. paronaella grahamensis carter was reported from numerous localities: from the lower pliensbachian to the aalenian of canada (carter et al., 1988; carter et al., 2010), from the pliensbachian of mexico (whalen & carter, 2002), greece table 1. taxonomic composition of studied samples of radiolarian cherts. a – abundant, c – common, r – rare. radiolarian taxa samples 18-15-6 18-15-7 18-15-8 18-16-7 bagotum maudense pessagno & whalen r beatricea sp. cf. b. christovalensis whalen & carter r beatricea sp. c r r bipedis hannai whalen & carter r c bipedis patricki whalen & carter r r c canoptum sp. cf. c. anulatum pessagno & poisson r canoptum sp. cf. c. artum yeh r charlottea weedensis whalen & carter r gorgansium gongyloideum kishida & hisada a c c c gorgansium morganense pessagno & blome r katroma sp. cf. k. irwingi whalen & carter r r c katroma ninstintsi carter c r c lantus sp. r pantanelluim sixi whalen & carter a r r paronaella grahamensis carter c c paronaella sp. cf. p. notabilis whalen & carter r praehexasaturnalis tetraradiatus kozur & mostler r pseudoeucyrtis busuangaensis (yeh & cheng) r c pseudoeucyrtis sp. cf. p. busuangaensis (yeh & cheng) r r udalia sp. cf. u. primaeva whalen & carter r figure 9. stratigraphic ranges of selected radiolarian taxa and proposed dating of the breccia unit. g eo lo gi a c ro at ic a 124 geologia croatica 75/1 (chiari et al., 2013), eastern russia (bragin & bragina, 2017), and austria (cifer et al., 2020). the range of this species is from the pliensbachian to the aalenian. praehexasaturnalis tetraradiatus kozur & mostler is present in the hettangian of germany (kozur & mostler, 1990), and canada (carter et al., 1998; carter & hori, 2005; longridge et al., 2007), the pliensbachian of mexico (whalen & carter, 2002), the hettangian to sinemurian of turkey (tekin, 2002), and the lower pliensbachian of austria (cifer et al., 2020). the range is hettangian to lower pliensbachian. pseudoeucyrtis busuangaensis (yeh & cheng) is known from the lower jurassic of the philippines (yeh & cheng, 1998), japan (hori, 2004), and oman (bleichschmidt et al., 2004). recently it is documented from the lower sinemurian – lower pliensbachian of turkey (tekin et al., 2020). udalia primaeva whalen & carter, 1998 is present in the hettangian and lower sinemurian of canada (carter et al., 1998) and from the hettangian to the sinemurian of turkey (tekin, 2002). the range of this species needs additional study. certain contradictions between the stratigraphic ranges of the radiolarian taxa are observed. for example, the last appearance data of bipedis hannai whalen & carter is upper sinemurian, whereas the first appearance data of katroma ninstintsi carter and paronaella grahamensis carter are lower pliensbachian. the age determination of this assemblage as it is, is estimated with caution as sinemurian–pliensbachian. sample 18-15-7 this sample yielded only few taxa determined at species level (fig. 9, table 1). these are: bipedis japonicus goričan et al., 2006 (hettangian? – pliensbachian?), gorgansium gongyloideum (kishida & hisada) (rhaetian – middle toarcian), katroma ninstintsi carter (pliensbachian), and pantanellium sixi whalen & carter (upper sinemurian). this poses a similar contradiction: between the ranges of katroma ninstintsi and pantanellium sixi. the age of the sample can be supposed to be sinemurian – pliensbachian. sample 18-15-8 only three species are represented here, two of them were determined in open nomenclature (fig. 9, table 1): gorgansium gongyloideum kishida & hisada, katroma sp. cf. k. irvingi whalen & carter and pseudoeucyrtis sp. cf. p. busuangaensis (yeh & cheng). their presence confirmed the early jurassic age of the sample, but did not allow more detailed dating. sample 18-16-7 this sample yielded a diverse and moderately well-preserved assemblage which slightly differs from sample 18-15-6. canoptum? megathelus cordey is present in the lower jurassic of canada (cordey, 1998). the stratigraphic importance of this species is poorly known. charlottea weedensis whalen & carter, 1998 was previously reported from the hettangian and lower sinemurian of canada (carter et al., 1998), from the middle jurassic (bathonian) of oregon (yeh, 2009), and from the hettangian – sinemurian of turkey (tekin, 2002). it seems that this species has a broad stratigraphic range – from the hettangian to the bathonian. gorgansium morganense pessagno & blome is known from the lower pliensbachian of british columbia (carter et al., 2010) and oregon (pessagno & blome, 1982; yeh, 1987). the stratigraphic range is questionable, because this species is studied only in two regions of north america. other species are the same as in sample 18-15-6: bipedis hannai whalen & carter (hettangian – sinemurian), bipedis japonicus goričan et al., 2006 (hettangian? – pliensbachian?), gorgansium gongyloideum kishida & hisada (rhaetian – middle toarcian), katroma ninstintsi carter (pliensbachian), pantanellium sixi whalen & carter (upper sinemurian), paronaella grahamensis carter (pliensbachian – aalenian), and pseudoeucyrtis busuangaensis (yeh & cheng) (lower sinemurian – lower pliensbachian). as a result, we have for this sample clear contradictions between the stratigraphic ranges of the determined samples. for example, the lad of bipedis hannai and pantanellium sixi is the upper sinemurian, while the fad for gorgansium morganense, katroma ninstintsi, and paronaella grahamensis is the lower pliensbachian. the presence of such contradictions in both of the two most diverse assemblages may be explained by the insufficient current knowledge of the lower jurassic radiolarian stratigraphic ranges and occurrences that need more detailed study. the age of this assemblage can be estimated only with caution as a broad range – sinemurian to pliensbachian. we cannot currently give a more precise age, but the presen ce of lower jurassic radiolarian chert layers in this breccia represents a significant discovery for the stratigraphy of the dhiarizos group, as previously a large hiatus (the lower jurassic and part of the middle jurassic) had been recorded in the typical sections of the mamonia complex (bragin & krylov, 1996, 1999). it should be noted that the lower jurassic radiolarian cherts are relatively rare in the mediterranean area (baumgartner et al., 2003; bortolotti et al., 2003; chiari et al., 2013). similar rare lower jurassic cherts are observed as intercalations within ophiolitic breccia in the old zod pass section of the lesser caucasus along the armenian-azerbaijan border zone (knipper et al., 1987), and as a chert unit (angelokastron chert) covered by the dhimaina and potami formations (ophiolitic sandstones and breccias) at the argolis in greece (chiari et al., 2013). the lower jurassic cherts intercalated with micritic limestones were described and dated by tekin et al. (2020) in southeastern turkey. 6. the origin and significance of breccia the studied block of volcaniclastic breccia represents a new undescribed unit of the dhiarizos group. it differs from other units of the dhiarizos group by its composition and origin. the breccia consists of fragments of metabasalts, diabases and metagabbro with minor fragments of siltstones. the supporting matrix of the breccia can vary – from sandy consisting of grains of diabase and other igneous rocks to recrystallized micritic carbonates. several beds of micritic limestone and radiolarian chert are present within the breccia. the presence of siltstone fragments and sedimentary contacts between the breccia, limestone and chert beds are an indication of the sedimentary origin of the breccia. the volcaniclastic breccia is closely related with the volcanic units of the dhiarizos group, such as the phasoula and loutra tis aphroditis formations, which could be the source of the clastic material. the breccia may have originated via underwater erosion of previously formed basic volcanics. the breccia is characterized by the irregular, poorly rounded character of the rock g eologia c roatica 125bragin et al.: the radiolarian age and petrographic composition of a block of the lower jurassic volcaniclastic breccia and chert of the mamonia ... fragments, and by the absence of any sorting or stratification. the deposition of the breccia was probably local – along steep slopes or in narrow depressions triggered by tectonic movements. the formation of the breccia took place simultaneously with deepwater carbonate-chert sedimentation. the beds of micritic limestone and radiolarian chert within the breccia display a close affinity with the upper triassic – lower jurassic kholetria member of the dhiarizos group. similar mesozoic volcaniclastic sedimentary breccias are known in various regions of the mediterranean, either related to the upper part of plutonic and intrusive sequences of ophiolite complexes or formed within volcanic sequences (knipper, 1978). the latter type is characterized by the predominance of clastic material consisting of dolerites, basalts and altered gabbro, while serpentinites are rare. these breccias can occur within or at the top of volcanic sections and they usually have sedimentary relationships with chert layers. such breccias were studied in detail in the ligurian alps (gianelli & principi, 1974). thus, the lower jurassic breccia in the akamas peninsula represents the lower part of the dhiarizos group sedimentary section. the presence of radiolarian cherts related with volcaniclastic breccia is of significant interest as according to many studi es the rhaetian to toarcian (liassic) cherts are very rare in the mediterranean region, and, if present, they can be related to breccias, as in the lesser caucasus (knipper et al., 1987) and greece (chiari et al., 2013). 7. conclusions volcaniclastic breccia of sedimentary origin, composed mainly of blocks and clasts of metabasalts, diabase and metagabbro, has been described from the akamas peninsula, western cyprus. interbeds of radiolarian cherts within breccia yield radiolari an assemblages that allow dating of the breccia as lower jurassic, sinemurian – pliensbachian. the triassic volcanics of the phasoula formation can be the source of the clastic material of the breccia. the breccia represents a previously unknown lower part of the sedimentary cover of the triassic volcanics (phasoula formation, mamonia complex). acknowledgements this work was supported by the russian foundation for basic research, grant 19-55-25001-cyprus_a, by the research and innovation foundation of cyprus (rif) under the grant bilateral/ russia (rfbr)/1118/0025 and by russian governmental assignment project 0114-2021-0003. the authors highly appreciate comments and corrections suggested by špela goričan and duje kukoč. references baumgartner, p.o., bernoulli, d., stampfli, g.m. & chiari, m. (2003): radiolarian ages, formation, and emplacement history of ophiolites in eastern greece. – in: interrad x, lausanne (switzerland), abstract, 30–32. bleichschmidt, i., dumitrica, p., matter, a., krystin, l. & peters, t. (2004): stratigraphic architecture of the northern oman continental margin – mesozoic hamrat duru group, hawasina complex, oman. – geoarabia, 9/2, 81–132. blome, c.d. & irwin, w.r. (1985): equivalent radiolarian ages from ophiolitic terranes of cyprus and oman. – geology, 13/6, 401–404. doi: 10.1130/0091-7613(1985)13%3c401:erafot%3e2.0.co;2 bortolotti, v., carras, n., chiari, m., fazzuoli, m., marcucci, m., photiades, a. & principi, g. (2003): the argolis peninsula in the palaeogeographic and geodynamic frame of the hellenides. – ofioliti, 28,79–94. bragin, n.y. (2007): late triassic radiolarians of southern cyprus. – paleontological journal, 41, 951–1029. doi: 10.1134/s0031030107100012 bragin, n.y. (2010): stratigraphy of mesozoic (upper triassic–lower cretaceous) volcanogenic-sedimentary deposits of the dhiarizos group, the allochthonous mamonia complex of cyprus. – stratigraphy and geological correlation, 18/2, 118–132. doi: 10.1134/s0869593810020024 bragin, n. & bragina, l. (2017): early and middle jurassic (pliensbachian to bajocian) radiolaria from cherts of kiselevka-manoma accretionary complex (amur river, eastern russia).– ofioliti 42: 1–19. bragin, n.y. & krylov, k.a. (1996): stratigraphy and lithology of the upper triassic deposits of southwestern cyprus (vlambouros formation). – stratigraphy and geological correlation, 4/2, 132–140. bragin, n.y. & krylov, k.a. (1999): stratigraphy and formation conditions of the jurassic siliceous and terrigenous deposits in southwestern cyprus.– stratigraphy and geological correlation, 7/4, 333–342. bragin, n.y., bragina, l.g. & krylov, k.a. (2000): albian–cenomanian deposits of the mamonia complex, southwestern cyprus.– in: panayides, i., xenophonthos, c. & malpas, j. (eds.): proceedings of the third international conference on the geology of the eastern mediterranean, nicosia, 1998, 309–315. bragina, l.g. (2012): radiolarian biostratigraphy of the perapedhi formation (cyprus): implications for the geological evolution of the troodos ophiolite.– bulletin de la société géologique de france, 183/4, 347–353. doi: 10.2113/gssgfbull.183.4.343 bragina, l.g. (2016): radiolarian-based zonal scheme of the cretaceous (albian– santonian) of the tethyan regions of eurasia.– stratigraphy and geological correlation, 24/2, 141–166. bragina, l.g. & bragin, n.y. (1996): stratigraphy and radiolarians from the type section of perapedhi formation (upper cretaceous of cyprus).– stratigraphy and geological correlation, 4/3, 246–253. bragina, l.g. & bragin, n.y. (2016): cretaceous (albian to turonian) radiolarians from chert blocks of moni mélange (southern cyprus).– revue de micropaléontologie, 59/4, 311–338. doi: 10.1016/j.revmic.2016.05.002 carter, e.s., cameron, b.e.b. & smith p.l. (1988): lower and middle jurassic radiolarian biostratigraphy and systematic, paleontology, queen charlotte islands, british columbia. – bulletin geological survey canada, 386, 1–109. carter, e.s. & hori, r.s. (2005): global correlation of the radiolarian faunal change across the triassic–jurassic boundary.– canadian journal of earth sciences, 42, 777–790. doi: 10.1139/e05-020 carter, e.s., whalen, p.a. & guex, j. (1998): biochronology and paleontology of lower jurassic (hettangian and sinemurian) radiolarians, queen charlotte islands, british columbia.– bulletin geological survey canada, 496, 1–162. carter, e.s., goričan, š., guex, j., o’dogherty, l., de wever, p., dumitrica, p., hori, r.s., matsuoka, a. & whalen, p. (2010): global radiolarian zonation for the pliensbachian, toarcian and aalenian.– palaeo., palaeo., palaeo., 297, 401–419. doi: 10.1016/j.palaeo.2010.08.024 chan, g.h.-n., malpas, j., xenophonthos, c. & lo, c.-h. (2007): timing of subduction zone metamorphism during the formation and emplacement of troodos and baër-bassit ophiolites: insights from 40ar-39ar geochronology.– geological magazine, 144, 797–810. doi: 10.1017/s0016756807003792 chan, g.h.-n., malpas, j., xenophonthos, c. & lo, c.-h. (2008): magmatism associated with gondwanaland rifting and neo-tethyan oceanic basin development: evidence from the mamonia complex, sw cyprus.– journal of the geological society, 165, 699–709. doi: 10.1144/0016-76492007-050 chiari, m., baumgartner, p.o., bernoulli, d., bortolotti, v., marcucci, m., photiades, a. & principi, g. (2013): late triassic, early and middle jurassic radiolaria from ferromanganese-chert “nodules” (angelokastron, argolis, greece): evidence for prolonged radiolarite sedimentation in the maliacvardar ocean.– facies, 59, 391–424. doi: 10.1007/s10347-012-0314-4 cifer, t., goričan, š., gawlick, h.-j., auer, m. (2020): pliensbachian, early jurassic radiolarians from mount rettenstein in the northern calcareous alps, austria.– acta palaeontologica polonica, 65/1, 167–207. doi: 10.4202/ app.00618.2019 cordey, f. (1998): radiolaires des complexes d’accrétion de la cordillére canadienne (colombie-britannique).– commission géologique du canada, bulletin 509, 1–209. gass, i.g. (1960): the petrography, structure and evolution of the troodos massif, cyprus.– (unpubl. phd thesis) – university of leeds, 279 p. gawlick, h.-j., suzuki, h. & missoni, s. (2001): nachweis von unterliassischen beckensedimenten in hallstätter fazies (dürrnberg-formation) im bereich der hallein-berchtesgadener hallstätter zone und des lammer beckens (hettangiumsinemurium).– mitteilungen ges. geol. bergbaustud österr., 45, 39–55. geological survey department of cyprus (2008): geological map of paphos–kallepeia area. nicosia, sheet 16 iii–iv. scale 1:25000. geological survey department of cyprus (2015): geological map of the pegeia–steni area. nicosia, sheet 16 i–ii. scale 1:25000. g eo lo gi a c ro at ic a 126 geologia croatica 75/1 gianelli, g. & principi, g. (1974): studies on mafic and ultramafic rocks. 4. breccias of the ophiolitic suite in the monto bocco area (ligurian apennine). – bolletino societa geologica italiana, 93, 277–308. goričan, š., carter, e.s., dumitrica, p., whalen, p.a., hori, r.s., de wever, p., o’dogherty, l., matsuoka, a. & guex, j. (2006): catalogue and systematics of pliensbachian, toarcian and aalenian radiolarian genera and species.– zrc publishing, scientific research centre of the slovenian academy of sciences and arts, ljubljana, 446 p. henson, f.r.s., browne, r.v. & mcginty, j. (1949): a synopsis of the stratigraphy and geological history of cyprus.– quarterly journal of the geological society of london, 105, 1–41. doi: 10.1144/gsl.jgs.1949.105.01-04.03 hori, r. (1990): lower jurassic radiolarian zones of sw japan.– trans. proc. palaeont. soc. japan, n. s., 159, 562–586. hori, n. (2004): jurassic radiolarians from chert and clastic rocks of the chichibu belt in the toyohashi district, aichi prefecture, southwest japan.– bulletin of the geological survey of japan, 55, 335–388. knipper, a.l. (1978): ophicalcites and some other types of breccia accompanying pre-orogenic formation of ophiolite assemblage. – geotectonics, 2, 50-66 (in russian). knipper, a.l., satian, m.a. & bragin, n.y. (1997): upper triassic-lower jurassic volcanogenic and sedimentary deposits of the old zod pass (transcaucasia). – stratigraphy, geological correlation, 3, 58–65. (in russian). kozur, h. & mostler, h. (1990): saturnaliacea deflandre and some other stratigraphically important radiolaria from the hettangian of lenggries/isar (bavaria, northern calcareous alps). – geol. paläontol. mitt. innsbruck, 17, 179–248. lapierre, h. (1975): les formations sédimentaires et éruptives des nappes de mamonia et leurs relations avec le massif du troodos.– mémoires de la société géologique de france, 123, 127 p. longridge, l.m., carter, e.s., smith, p.l., & tipper, h.w. (2007): early hettangian ammonites and radiolarians from the queen charlotte islands, british columbia and their bearing on the definition of the triassic–jurassic boundary.– palaeogeography, palaeoclimatology, palaeoecology, 244, 142–169. doi: 10.1016/j. palaeo.2006.06.027 malpas, j., xenophonthos, c. & williams, d. (1992): the ayia varvara formation of sw cyprus: a product of complex collisional tectonics. – tectonophysics, 212, 193–211. doi: 10.1016/0040-1951(92)90291-d martini, r., peybernés, b. & moix, p. (2009): late triassic foraminifera in reefal limestones of sw cyprus. – journal of foraminiferal research, 39/3, 218–230. doi: 10.2113/gsjfr.39.3.218 pessagno jr., e.a. & whalen, p.a. (1982): lower and middle jurassic radiolaria (multicyrtid nassellariina) from california, east-central oregon and the queen charlotte islands, b.c.– micropaleontology, 28, 111–169. doi: 10.2307/1485228 robertson, a.h.f. (1977): the kannaviou formation, cyprus: volcaniclastic sedimentation of a probable late cretaceous volcanic arc.– journal of the geological society london, 134/3, 269–292. doi: 10.1144/gsjgs.134.3.0269 robertson, a.h.f. & hudson, j.d. (1974): pelagic sediments in the cretaceous and tertiary history of cyprus.– in: hsu, k.j. & jenkyns, h.c. (eds.): pelagic sediments: on land and under the sea.– special publications international association sedimentologists, 1, 403–436. robertson, a.h.f. & woodcock, n.h. (1979): mamonia complex, southwest cyprus: evolution and emplacement of a mesozoic continental margin.– bull. geol. soc. of america, 1/9, 651–665. doi: 10.1130/0016-7606(1979)90%3c651: mcscea%3e2.0.co;2 swarbrick, r.e. & robertson, a.h.f. (1980): revised stratigraphy of the mesozoic rocks of southern cyprus.– geological magazine, 117/5, 547–563. doi: 10.1017/s0016756800028892 tekin, u.k. (2002): lower jurassic (hettangian–sinemurian) radiolarians from the antalya nappes, central taurids, southern turkey.– micropaleontology, 48/2, 177–205. doi: 10.2113/48.2.177 tekin, u.k., krystyn, l., okuyucu, c., bedi, y., sayit, k. (2020): late triassic to early jurassic radiolarian, conodont and ammonite assemblages from the tavuscayiri block, mersin mélange, southern turkey: time constraints for the t/j boundary and sedimentary evolution of the southern margin of the northern neotethys. – geodiversitas, 42/27, 493–537. doi: 10.5252/geodiversitas2020v42a27 torley, j.m. & robertson, a.h.f. (2018): new evidence and interpretation of facies, provenance and geochemistry of late triassic–early cretaceous tethyan deep-water passive margin-related sedimentary rocks (ayios photios group), sw cyprus in the context of eastern mediterranean geodynamics.– sedimentary geology, 377, 82–110. doi: 10.1016/j.sedgeo.2018.09.001 whalen, p.a. & carter, e.s. (1998): systematic paleontology.– in: carter, e.s., whalen, p.a. & guex, j. (1998): biochronology and paleontology of lower jurassic (hettangian and sinemurian) radiolarians, queen charlotte islands, british columbia. geological survey of canada bulletin, 496, 1–147. whalen, p.a. & carter, e.s. (2002): pliensbachian (lower jurassic) radiolaria from baja california sur, mexico.– micropaleontology 48/2, 97–151. doi: 10.2113/48.2.97 wilson, r.a.m. (1959): the geology and mineral resources of the xeros–troodos area.– memoirs geological survey cyprus 1, 1–136. yao, a. (1997): faunal change of early-middle jurassic radiolarians. – news of osaka micropaleontologists, spec. vol. 10, 155–182. yeh, k.-y. (1987): taxonomic studies of lower jurassic radiolaria from east-central oregon.– national museum of natural science, special publication 2, 1–169. yeh k.-y. (2009): a middle jurassic radiolarian fauna from southfork member of snowshoe formation, east-central oregon.– collection and research 22, 15–125. yeh, k.-y. & cheng, y.-n. (1998): radiolarians from the lower jurassic of the busuanga island, philippines.– bull. nat. mus. nat. sci. (taiwan) 11, 1–65. g eologia c roatica 127bragin et al.: the radiolarian age and petrographic composition of a block of the lower jurassic volcaniclastic breccia and chert of the mamonia ... plate 1. lower jurassic radiolaria (spumellaria) a, b – pantanellium sixi whalen & carter; c, d – gorgansium gongyloideum kishida & hisada; e – gorgansium morganense pessagno & blome; f – charlottea weedensis whalen & carter; g – paronaella grahamensis carter; h – praehexasaturnalis tetraradiatus kozur & mostler; i – beatricea? argescens (cordey); j – paronaella sp. cf. p. notabilis whalen & carter; k – udalia primaeva whalen & carter; l, m – udalia spp. magnification – 1-5, 8 – 1; 6, 7, 9-13 – 2. scale 100 μm. figs. a, b, c, g, i, k, l, m – sample 18-15-6; figs. d, e, f, h, j – sample 18-16-7 g eo lo gi a c ro at ic a 128 geologia croatica 75/1 plate 2. lower jurassic radiolaria (nassellaria) a, b – bipedis japonicus hori; c, h – bipedis hannai whalen & carter; d – pseudoeucyrtis busuangaensis (yeh & cheng); e – pseudoeucyrtis sp. cf. p. busuangaensis (yeh & cheng); f, g – katroma ninstintsi carter; i – bagotum maudense pessagno & whalen; j – canoptum? megathelus cordey; k, l – canoptum sp. cf. c. anulatum pessagno & poisson; m – katroma sp. cf. k. irvingi whalen & carter; n – lantus sp. cf. l. obesus (yeh). scale 100 μm. figs. a, b, f, i, k, l, n – sample 18-15-6, fig. e – sample 18-15-8; figs. c, d, g, h, j, m – sample 18-16-7 www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2024 | 77/3 | 243–251 | 5 figs. | 2 suppl. tabs. | 1. introduction speleothems, cave carbonate deposits that decorate many karst caves around the world, are valuable continental natural archives of past climate changes. the vast majority of palaeoclimate studies dealing with speleothems utilised their geochemical properties, (also known as proxies), to explore the causes and timing of past climate variability at sub-annual to orbital timescales (treble et al., 2003; borsato et el., 2007; drysdale et al., 2009; cheng et al., 2016; warken et al., 2018). among all the geochemical properties, the isotopic composition of oxygen and carbon are the most often used, while an increasing number of studies apply a multi-proxy approach by combining these two commonly used proxies with other geochemical properties, including for example trace element ratios, fluorescence, and petrography. although a multi-proxy approach generally improves the reliability of palaeoclimate reconstructions from speleothems, the underlying climate signal is not always straightforward to interpret because the proxy-climate relationship can be affected by site specific processes. these site-specific processes may occur in the soil and epikarst zone above the cave or within the cave itself, including for example changes in hydrological routing (treble et al., 2022), cave ventilation (spötl et al., 2005; mattey et al., 2010), or evaporation in seasonality in cave dripwater and air properties – implications for speleothem palaeoclimatology, nova grgosova cave (croatia) petra bajo1, maja briški1,*, anica benutić2, aneta piplica3, vlatko brčić1, bernardo marciuš2, iva palatinuš1 and andrej stroj1 1 croatian geological survey, milana sachsa 2, 10000 zagreb, croatia; (*corresponding author: mbriski@hgi-cgs.hr) 2 croatian institute of public health, rockfellerova 7, 10000 zagreb, croatia 3 faculty of veterinary medicine, heinzelova 55, 10000 zagreb, croatia doi: 10.4154/gc.2024.16 abstract due to the wealth of climate-sensitive properties, speleothems have been propelled into prominence as one of the most powerful continental archives of past climate changes. however, the multitude of processes that operate in the unsaturated karst zone and in the cave atmosphere can make palaeoclimate interpretations of the speleothem proxies challenging and site specific. hence, to better understand the climate-proxy relationship, cave monitoring studies are usually undertaken. here, we present the first results of an ongoing cave monitoring study in the nova grgosova cave in croatia covering an eighteen-month long monitoring period. the driving mechanisms for mg/ca and sr/ca variability in dripwater samples that feed ten stalagmites are discussed. the results reveal high variability in infiltration among the monitored sites as well as strong seasonal variability in cave air carbon dioxide (co2) concentrations. a strong positive correlation between dripwater mg/ca and sr/ca suggests that prior calcite precipitation (pcp) is taking place at this site affecting the chemical composition of dripwater. principal component analysis furthermore reveals that dripwater mg/ca and sr/ca are in strong negative correlation with cave air co2 concentrations, while there is a weak correlation with dripwater quantity. cave ventilation is a primary process leading to the pcp at the nova grgosova cave. the seasonality revealed in this study suggests the possibility that the mg/ca and sr/ca ratio in the speleothems from this cave site can be used to aid seasonal reconstructions of past climate conditions in central croatia and beyond. the epikarst and/or cave environment (mickler et al., 2004) all of which may mask the ingenious climate signal. to better understand how the climate signal is transferred into speleothem proxies at a particular cave site, it is common nowadays to perform complex monitoring campaigns. these monitoring studies, particularly when performed for longer time periods, (treble et al., 2015; tadros et al., 2016; riechelmann et al., 2022) sometimes almost over a decade (treble et al., 2015; tadros et al., 2019), are often of paramount importance for reliable palaeoclimate interpretation of the studied speleothem proxies. magnesium and strontium easily substitute calcium in the carbonate crystal lattice, and they are the most often utilised trace elements (te) in speleothem palaeoclimatology. the uptake of these elements into carbonate is described by the partition coefficient (k) defined as kte = [te/ca] carbonate / [te/ca] dripwater. partition coefficients for both elements are experimentally determined and relatively well understood (day & henderson, 2013; wassenburg et al., 2020). magnesium and strontium in dripwater may be sourced from atmospheric dust and overlying soil, but in most of the cases the main source is the bedrock (fairchild & treble, 2009; riechelmann et al., 2022). numerous studies reveal that the trace element to calcium (te/ca) ratio of cave article history: manuscript received: may 08, 2024 revised manuscript accepted: july 09, 2024 available online: october 01, 2024 keywords: cave monitoring, cave air co2 concentrations, recharge, dripwater mg/ca and sr/ca, icp-ms, nova grgosova cave, croatia g eo lo gi a c ro at ic a 244 geologia croatica 77/3 dripwaters, and hence of speleothems is not constant through time and that it may be responsive to several climate and environmental processes operating in the unsaturated karst zone above the cave (mcdonald et al., 2004; nava-fernandez et al., 2020; wortham et al., 2021; bernal et al., 2023) as well as the processes occurring within the cave itself (mattey et al., 2010; treble et al., 2015; lyu et al., 2023). the predominance of a particular process affecting the dripwater te/ca ratio can be cave specific (treble et al., 2015; tadros et al., 2016), but it can also vary among the observed drip sites within a single cave (wong et al., 2011; tremaine & froelich, 2013). here, we present the first results of an ongoing cave monitoring campaign undertaken at nova grgosova cave in central croatia. the isotopic composition of oxygen and carbon in two speleothems from this site has already been used to explore climate variability throughout the holocene (surić et al., 2021), underpinned by 12 consecutive months of cave monitoring results (surić et al., 2018). the results published in surić et al. (2018) revealed seepage flow for two drip sites and a seasonal flow type for one monitored dripsite. the stable isotope composition record for this 12 month period implies well homogenised groundwater for three monitored dripsites (surić et al., 2018). in this new research, we expand the monitoring into more detailed investigations of the processes occurring in the atmosphere, soil, cave air and modern speleothems, in order to gain better understanding of the proxy climate relationship at this cave site. here, we discuss the variations in dripwater elemental ratios (sr/ca and mg/ca) and explore their potential for palaeoclimate research of speleothems from this site. we provide the first interpretations for the observed patterns by combining hydrochemistry data with monitoring results of cave air microclimate properties, (i.e., the carbon dioxide concentration of cave air) and dripwater recharge data. the results presented in this study will support palaeoclimate interpretations of geochemical proxies in speleothems from this cave site which is the subject of ongoing research. 2. study site location, climate and geological setting the nova grgosova cave is located in the samobor hills in northwestern croatia (45⁰49’7” n, 15⁰40’42” e, 239 m asl) about 30 km to the west of the capital city of zagreb (fig. 1). the explored sections of the cave have a relatively simple morphology, featuring a few chambers linked by a single passage with a total length of 97 m, depth of 14 m and no active river flow (fig. 1a). it is important to note, however, that these passages were predominantly filled with sediments, including both clastic materials and speleothems. it is likely that the explored portion represents only a small fragment of the entire network of passages. slightly less than one hundred metres figure 1. geographic, geological and climate setting of the nova grgosova cave. plan of the cave with marked positions of ten sampling locations (a). local geological setting with basic chronostratigraphic units (šikić et al., 1978, 1979; vrsaljko et al., 2005). position of the cave is marked with letter a (b). climate of the area is characterised as temperate humid continental with warm summers according to köppen classification (c). photographs of cave monitoring set up in nova grgosova cave (d and e). g eologia c roatica 245bajo et al.: seasonality in cave dripwater and air properties – implications for speleothem palaeoclimatology, nova grgosova cave (croatia) away, there is an entrance to another cave (the stara grgosova cave), with passages developed on two levels. both caves lacked natural entrances and were only discovered during quarrying and construction works in the hill slope. while no direct connection between them has been found, it is highly probable that these caves are parts of the same interconnected system. the nova grgosova cave was sealed with metal doors soon after discovery in 2004. it is open for touristic visits throughout the year. cave monitoring has been conducted at the far end of the cave, in a lower chamber not accessible to tourists. the climate of the wider area is classified as belonging to the type cfb – continental temperate humid with warm summers (peel et al., 2007). the mean annual temperature of the area is 11.4 °c and the mean annual precipitation is 1089 mm, both based on meteorological data collected from 1981 to 2023 at the samobor meteorological station located 3 km away from the cave site, (data provided by croatian meteorological and hydrological service – cmhs, 2024). the annual distribution of rainfall is uniform with the maximum in september and a minimum recorded in january (fig. 1c). maximum temperatures are recorded in july and minimum in january (fig. 1c). potential evapotranspiration is at its maximum during the summer months (surić et al., 2018) causing the main infiltration season to coincide with the colder part of the year (i.e., from october to march). the nova grgosova cave is formed in the so called “lithothamnium limestones” (fig. 1b, m4), shallow-marine carbonates deposited from the middle to upper badenian (šikić et al., 1978, 1979; vrsaljko et al., 2005). these biolithic limestones were formed in reef to lagoonal (rhodolitic and back reef bioclastic facies) paleoenvironments, in a temperate to subtropical climate zone of the southwestern part of central paratethys. vertical and lateral distributions of these deposits shows diversification of the depositional conditions followed by synsedimentary tectonic movements (magyar et al., 1999; vrsaljko et al., 2005). the nova grgosova cave area tectonically belongs to the border zone between the eastern and southern alps, dinarides and the pannonian basin, south of the periadriatic line, with highly deformed preneogene units (tomljenović & csontos, 2001). these deposits are most commonly in tectonic and transgressive contact with mesozoic carbonates of the žumberak mt. (šikić et al., 1978, 1979). 3. methodology – sampling, analyses and data processing the dripwater results we present here were collected between october 2022 and february 2024 at 10 monitoring locations positioned above stalagmites spread around the cave chamber (fig. 1). the monitoring set up is composed of a drip logger, above which a watch glass is placed for harvesting recent carbonate samples. the drip logger is positioned in the funnel firmly attached to a bottle which is in some cases connected with the tubing to the canister of various sizes. the water from the bottle and canister is collected and analysed monthly usually at the end of the calendar month. the co2 concentrations in the cave air were measured with a handheld vaisala mi70 meter attached to the gmp252 co2 probe (manufacturer’s accuracy: +/2% for readings in the range 3000 10 000 ppm) during monthly cave visits. another vaisala mi70 meter with gmp252 co2 probe is kept in the cave chamber for monitoring of co2 concentrations at hourly resolution and the results replicate well (unpublished data). temperature and relative humidity were recorded at hourly intervals by a hobo onset pro v2 temperature and relative humidity logger beginning from december 2022. the logger was mounted in a holder off the cave wall, next to the position of the ng-2 stalagmite (fig. 1). the amount of infiltrated water at ten drip locations was monitored by stalagmate acoustic driploggers (collister & mattey, 2008) at an hourly resolution. for this study, we calculated the number of drips corresponding to the time periods between the dripwater sample collection dates so that the resolution is comparable to other parameters discussed (i.e., trace metal to calcium ratios and co2 in the cave air). we used a 0.05 conversion factor for converting the number of drips to litres. the factor was selected based on the cross check of the total calculated volume with field notes of the approximate amount of water collected in containers between the two visits. as the volume of the collected water exceeded the canister capacity in some cases (i.e., ng-2 and ng-11), we were not able to do the comparison for those data. a 20 ml aliquot of dripwater was filtered with a chromafill xtra pfte 1 µm filter, subsampled to an acid-clean hdpe bottle, and acidified in the cave with 20 µl of 60% suprapure hno3 in order to prevent carbonate precipitation pre-analyses. the samples were stored in a refrigerator (≈ 4 °c) and analysed within a few days at the croatian institute for public health in zagreb. a total of 176 dripwater samples were analysed throughout the study period. a larger number of elements was analysed, but here we focus on mg, sr and ca results. sample analysis was undertaken on an icp-qms system (agilent technologies, icp-ms 7900). calibration was performed with standard element calibration solutions 1000 mg/l for ca and mg (certified reference material, cpa chem) and a multi-element calibration solution 10 µg/ml (multi-element calibration standard 2a, agilent technologies) for sr. estimated measurement uncertainties for mg, sr and ca were 11%, 8% and 20% respectively. two samples of the host rock were sampled for elemental analysis. one sample (ng rock 1) was sampled from the surface outcrop above the cave. another sample (ng-wr-1) was taken from the weathered zone at 30 to 40 cm depth and is composed of 5 to 10 cm large fragments of host rock. microwave digestion of samples was performed in a closed microwave digestion system (multiwave go, anton paar). approximately 50 mg large subsamples were weighed with the addition of 2 ml mili-q water (18,2 mω at 25 °c), 5 ml nitric acid (hno3, traceselecttm ≥ 69%) and 2 ml hydrogen peroxi de (h2o2, suprapure® 30%) into teflon digestion vessels. sample blanks were prepared using the same amount of reagents. the microwave digestion programme was set as follows: tmax = 185 °c (ramp = 10 min, hold = 10 min). after digestion, g eo lo gi a c ro at ic a 246 geologia croatica 77/3 each sample aliquot was quantitatively transferred to a 50 ml pp sample cup and diluted with mili-q water to approximately 50 g. no precipitate or residue was observed. samples were analysed on an icp-qms system (agilent technologies, icpms 7900) at the croatian institute for public health in zagreb. calibration was performed with standard element calibration solutions: 1000 mg/l for ca and mg (certified reference material, cpa chem) and multi-element calibration solution 10 µg/ml (multi-element calibration standard 2a, agilent technologies) for sr. estimated measurement uncertainties for mg and ca were both 5% and 6% for sr. to unravel the underlying patterns and relationships among the collected dataset, principal component analysis (pca) was employed. the parameters used in analysis included cave air co2 concentrations, dripwater amount and dripwater mg/ca and sr/ca ratios. in the statistical programming language r (r core team, 2024), the factominer and factoextra packages were utilized for the pca analysis, tailored to the specific requirements of the study. before conducting pca, all the variables were standardized individually for each sampling location, except for the ng-9 sample as explained further below. the standardization ensured that the data were on a comparable scale and retained information about spatial variability across the study area. 4. results magnesium, strontium and calcium concentrations, mg/ca and sr/ca molar ratios, dripwater amount, cave air temperature and co2 concentrations are all listed in supplement table 1. dripwater quantity results reveal high variability between the sites. due to the large spread in the data, they are presented on two separate y-axes in figs. 2a and 2b. the minimum monthly amount of 25 ml was recorded in the sample collected in november 2022 at the site ng-9 and a maximum monthly amount of > 49 l was registered in february 2023 at site ng-2. the time series analyses of the monthly data presented here, demonstrate that some sites display uniform drip rates (e.g., ng-3, ng-9, ng-10 and ng-11) with no seasonal variability, while others show higher variability in dripwater quantities throughout the investigated period (e.g., ng-2, ng8, ng-12, ng-13, ng-14 and ng-15). monthly data on co2 concentration in the cave air (fig. 2c) show large seasonal variations with lower co2 values observed from november to april, and higher co2 throughout the rest of the year. a minimum of 658 ppm was measured during the cave visit on the 1st of march 2023 (winter), and a maximum of 7600 ppm was recorded on the 30th of august 2022 (summer). although exploring the mechanisms responsible for seasonal fluctuations in the cave air co2 is beyond the scope of this publication, it is likely that the observed seasonality in cave air co2 in nova grgosova cave is caused by ventilation of the cave driven by strong outside temperature seasonality (fig. 1). seasonal temperature variability at the surface leads to differences in density between surface and cave air, a process often observed in other mid-latitude cave sites (spötl et al., 2005; frisia et al., 2011; van rampelbergh et al., 2014; treble et al., 2015; gabrovšek, 2023). our results demonstrate effective cave ventilation during periods of colder air outside the cave compared to the cave air, which leads to a decrease in cave air co2 concentration. the monthly average data on cave air temperature and relative humidity are presented in supplement table 2. the average monthly cave air temperature is 11.42 +/–0.01 °c, throughout the monitoring period. the cave temperature is stable throughout the year and corresponds to the average surface temperature of 11.4 °c as measured at samobor meteoro logical station (cmhs, 2024) for the period 1981–2023. results on relative humidity reveal 100% saturation throughout the monitoring interval. however, these data should be taken with caution due to the possibility of instrument malfunction when the saturation of 100% is reached. dripwater magnesium results (fig. 3a) reveal low and rather stable concentrations throughout the monitoring period and most of the samples are within the range from 600 to 1500 ppb. the maximum mg concentration is observed at site ng9, which also shows the largest variability in mg concentration in the whole dataset. the higher variability in ng-9 data compared to all other sites may be a result of different hydrogeological characteristics of the preferential flow paths feeding this particular stalagmite. to confirm this particularity, a longer time series and higher resolution data are needed. dripwater strontium data (fig. 3b) do not display seasonal variability, similar to the mg results. most of the samples range in between 70 ppb and 110 ppb. the maximum of 165 ppb is recorded in sample ng-10 collected in july 2023. indeed, all samples collected in july 2023 show an unusual systematic increase in sr concentrations, accompanied by a systematic increase in mg and a decrease in ca concentrations. this sugfigure 2. dripwater amount (a i b) and cave air co2 concentration (c) results. while co2 shows strong seasonal variability, dripwater amount data reflective of discharge at particular monitoring positions reveal a large range in data as well as differences in variability between the monitored sites. g eologia c roatica 247bajo et al.: seasonality in cave dripwater and air properties – implications for speleothem palaeoclimatology, nova grgosova cave (croatia) gests a possible analytical problem with this dataset. therefore, the results from samples collected in july 2023 are considered as outliers and were not included in further statistical treatment of the data nor their discussion. unlike mg and sr, ca results (fig. 3c) reveal strong seasonal variability with higher values measured in the summer and autumn while lower ca concentrations are generally observed in samples from the winter and spring seasons. a maximum of 95 630 ppb was observed in sample ng-13 in october 2022, and a minimum of 30 239 ppb was recorded in january 2024 at site ng-8. the majority of the observed sites reveal seasonal variability in their trace elements to calcium ratios, although seasonality is more pronounced in the sr/ca than in the mg/ca data (figs. 3d and 3e). a minimum of mg/ca of 10.431 mmol/ mol (ng-13) was recorded in october 2022, and a/maximum of 78.542 mmol/mol (site ng-8) in january 2024. a minimum in sr/ca of 0.40157 mmol/mol (site ng-11) was observed in august 2023, and a maximum of 1.4398 mmol/mol (site ng-8) in january 2024. 5. discussion results of our study indicate a strong positive correlation between mg/ca and sr/ca with the pearson correlation coefficient (r) ranging from 0.89 (ng-15) to 0.98 (ng-2), (p<0.001) for all samples except ng-9 (supplement table 2). a positive correlation between mg/ca and sr/ca in cave dripwaters and in speleothems is often interpreted as an indication of prior carbonate precipitation (pcp) (fairchild et al., 2000; tooth & fairchild, 2003; riechelmann et al., 2022). pcp is defined as a process of carbonate precipitation from percolation solution enroute, within the unsaturated karst zone or in the cave, but prior to the dripwater collection site (fairchild et al., 2000). sinclair et al. (2012) proposed that the slope of a trendline through ln(mg/ca) versus ln(sr/ca) in speleothems or dripwater samples spanning from 0.709 to 1.003 is indicative of pcp affecting the te/ca ratio at the monitored location. wassenburg et al. (2020) showed that an even larger range (up to 1.45) in the slope is possible if pcp plays a main role in infiltration by considering variable partition coefficients for mg and sr as well as accounting for variable host rock composition. our ln(mg/ca) vs ln(sr/ca) (fig. 4a) shows slopes ranging from 1.01 to 1.15 and this indicates a strong effect of pcp in the infiltration dynamics at all the monitored locations, apart for site ng-9. the slope for site ng-9 is only 0.33. this different behaviour of ng-9 data compared to other sampling locations might be related to a high variability of mg content in groundwater feeding this drip site but is yet to be resolved in more detail in future research. pcp may be driven by two processes, often operating at the same time: 1) variability in water residence time in the epikarst because of seasonal variations in the infiltration process (wortham et al., 2021; riechelmann et al., 2022; bernal et al., 2023) and 2) seasonal variability in cave air co2 concentrations (treble et al., 2015; lyu et al., 2023). during dry periods, the infiltration amount is usually low and the infiltrated water will equilibrate with a lower pco2 in the unsaturated zone, causing calcite (or aragonite) precipitation in the air-filled voids. since the partition coefficient of mg and sr is much smaller than 1, mg/ca and sr/ca in the remaining water solution, and hence in dripwater will increase. drier periods will also result in a lower drip rate in the cave, additionally enhancing the pcp on the cave ceiling (johnson et al., 2006). conversely, during wet periods, the epikarst is saturated with water and few air-filled voids are available. therefore, an earlier degassing process in the epikarst is unlikely to occur, leading to a lower influence of pcp on mg/ca and sr/ca ratios in cave dripwater. mg/ca and sr/ca ratios in dripwater can additionally be influenced by variations in the water-rock interaction including processes such as recrystallization or the incongruent dis solution of calcite/dolomite (tooth & fairchild, 2003). the role of incongruent dissolution of dolomite can be excluded from this study site, because the host rock is mainly limestone with no observed dolomite. this is additionally evidenced in low mg and sr concentrations and the low mg/ca ratio of the analysed host rock samples (supplement table 1, fig. 4b), as well as in the analysed dripwater samples (fig. 4b), compared to other studies where dolomite is present within the cave host rock (tremaine & froelich, 2013; wassenburg et al., 2020). recrystallization and incongruent dissolution of calcite (icd) is another possible process which could lead to positive figure 3. magnesium (a), strontium (b) and calcium (c) contents in dripwater; magnesium to calcium (d) and strontium to calcium (e) ratios. samples from july 2023 are identified as outliers (for explanation please see the text) and they are not included in the plot with mg/ca and sr/ca molar ratios. g eo lo gi a c ro at ic a 248 geologia croatica 77/3 dripwater mg/ca and sr/ca correlation, but to make the distinction between pcp and icd, additional methods should be applied including sr isotopic composition of dripwater (wong et al., 2011). however, both processes pcp and icd would have the same effect on the mg/ca and sr/ca ratios in the dripwater (wong et al., 2011) and would increase the mg/ ca and sr/ca ratios during drier periods. this is unlikely to occur in the nova grgosova cave, because higher mg/ca and sr/ca ratios correspond to seasons with higher infiltration, rather than drier periods. another driving process for pcp is the variability in co2 concentration of the cave air. this is particularly evident in mid-latitude ventilated caves, where seasonal changes in surface air temperature a density difference between air at the surface and within the cave, leading to stronger ventilation during the cooler period of the year. such a process would lead to lower cave air co2 concentrations during the cooler part of the year, and weaker or no ventilation during warmer periods resulting in higher cave air co2 concentrations (spötl et al., 2005; frisia et al., 2011.; kukuljan et al., 2021). in the nova grgosova cave, the cave air temperature is stable throughout the year and it is very close to the mean annual surface temperature. however, the cave air co2 concentration is highly sensitive to the seasonal difference between surface and cave air temperatures, thus depicting a ventilation process occurring in the studied cave. lower cave air co2 concentrations during the cooler season would increase the in-cave pcp process through the increase of degassing and the precipitation of carbonate in the form of stalactites or soda straws on the cave ceiling. an increase of mg/ca and sr/ca ratios in the remaining dripwater seems to follow such a process. in contrast, increased cave air co2 concentrations during warmer seasons would suppress the in-cave pcp, leading to a decrease in dripwater mg/ca and sr/ca ratios. numerous stalactites and soda straws observed on the ceiling of the nova grgosova cave, as well as a disproportionate number of stalagmites on the cave floor also indicate the important role of in-cave pcp at this cave site. to further distinguish between hydrological and cave atmosphere effects on pcp evidenced in the strong positive correlation of mg/ca and sr/ca ratios, principal component analysis (pca) was utilised. the analysis was undertaken for data from all the monitored locations, except for site ng-9 where pcp was not identified as a major influencing factor, according to the criteria of sinclair et al. (2012) and wassenburg et al. (2020). the results of pca analysis are presented in figure 5. on the pca biplot (fig. 5), sr/ca and mg/ca are positioned close to each other confirming the strong correlation between both parameters, because of the influence of pcp. the inverse relationship of the mg/ca and sr/ca ratios with respect to the cave air co2 concentrations on the pca biplot, indicate a strong negative correlation between mg/ca (sr/ca) and co2. in contrast, the position of mg/ca and sr/ca with respect to the dripwater amount on the pca biplot, indicate a weak correlation between mg/ca and sr/ca ratios and dripwater quantity. the pca analysis results reveal that two principal components explain a total of 92% of the variance in the dataset. pc1 explains a substantial portion of the variance (68%), while pc2 accounts for an additional 24% of the variance. in the context of our study, pc1 most likely reflects the dominant influence of cave ventilation on the seasonal variability in cave air co2 concentrations and consequently, dripwater mg/ca figure 4. dripwater ln(mg/ca) versus ln(sr/ca) data for each of ten monitored locations with linear fits. slopes of the fit lines span from 1.01 to 1.15 indicating prior carbonate precipitation influence at nine out of ten dripwater sites (a). mg/ca vs sr/ca data plotted with respect to the two host rock samples. red circles present samples corresponding to the may to october collection period, and blue circles indicate samples collected from november to april (b). g eologia c roatica 249bajo et al.: seasonality in cave dripwater and air properties – implications for speleothem palaeoclimatology, nova grgosova cave (croatia) and sr/ca ratios. pc2, although explaining a smaller portion of the total variance (24%), represents an additional mode of variation, distinct from pc1. in our study, pc2 most likely reflects the influence of dripwater amount on the dripwater mg/ca and sr/ca ratios. however, the mg/ca and sr/ca are positioned almost under 90⁰ with respect to the dripwater amount, indicating a weak correlation between mg/ca and sr/ca and dripwater amount. taken together, the analyses reveal that seasonal changes in cave air co2 is the main driver of pcp observed in this dataset. low air co2 concentrations during the cooler period (from november to april), will increase the degassing process and calcite precipitation on soda straws and stalactites, thus increasing the pcp influence on dripwater trace element composition. in contrast, higher co2 concentrations from may to october, due to low ventilation conditions, will suppress the pcp effect. the dripwater composition is closer to the bedrock values (fig. 4b) during this warmer part of the year. the results of this ongoing study show the role of seasonal changes in cave air co2 in modifying mg/ca and sr/ca ratio in cave dripwater of the nova grgosova cave. if the dripwater is supersaturated with calcite throughout the year, it is likely to expect that the seasonality observed in dripwater te/ca would be captured in speleothems in this cave. depending on the growth rate te/ca, particularly sr/ca, ratio in speleothems from nova grgosova cave can then be used as a seasonality proxy in palaeoclimate studies from these speleothems. 6. conclusions cave monitoring program over 18 months has been conducted in nova grgosova cave (croatia) encompassing dripwater chemical composition (mg/ca and sr/ca ratios) and dripwater amount at 10 drip sites as well as cave air properties (co2 concentration, temperature and relative humidity). two host rock samples were additionally collected and analysed for their mg/ca and sr/ca ratios. the results of the cave monitoring program conducted in this cave so far show strong seasonal variability in cave air co2 concentrations. water infiltration is generally higher in winter and spring, and lower in summer and autumn, but it is very variable among the monitored sites. some of the observed sites do not show any seasonal variability in the dripwater amount. mg/ca and sr/ca ratios for nine drip sites reveal a strong positive correlation with a slope ranging from 1.01 to 1.15 on the ln(sr/ca) vs ln(mg/ca) plots. such correlations imply the influence of pcp on sr/ca and mg/ca ratios in the cave dripwater. pca analysis between te/ca ratios, co2 concentrations in the cave air and dripwater amount shows that the pcp at nova grgosova cave is likely driven by the seasonal variability in cave air co2 due to cave ventilation. the role of dripwater amount related to the seasonal infiltration is probably of minor importance. assuming continuous supersaturation of the dripwater throughout the year, it is likely that the seasonal change in dripwater chemical composition would be reflected in the mg/ca and sr/ca ratios of the calcite. acknowledgment we acknowledge financial support from croatian science foundation installation grant scheme (unlock-cave project, uip-2020-7355) and a croatian geological survey internal research project „grga“, funded by the national recovery and resilience plan 2021–2026 of the european union figure 5. results of principal component analysis confirm the strong positive correlation between mg/ca and sr/ca indicative of pcp and strong negative correlation between te/ca ratios and cave air co2 concentrations but weak correlation to dripwater amount. the arrow lines are used to reflect the variables of the dataset (parameters), and dots are used to show the observations (samples). the different colours correspond to the samples taken at different months throughout the monitoring period. g eo lo gi a c ro at ic a 250 geologia croatica 77/3 – next-generation eu, monitored by the ministry of science and education of the republic of croatia. we also thank the grgos family for their kind support and for giving us access to the cave site. we are grateful to two anonymous reviewers and a guest editor for their constructive comments. references bernal, j.p., revolorio, f., cu-xi, m., lases-hernández, f., piacsek, p., lachniet, m.s., beddows, p.a, lucia, g., lópez-aguiar, k., capella-vizcaino, s., lópez-martinez, r. & vásquez, o.j. (2023): variability of trace-elements and δ18o in drip water from gruta del rey marcos, guatemala; seasonal and environmental effects, and its implications for paleoclimate reconstructions.– front. earth. sci., 11, 1112957. doi: 10.3389/feart.2023.1112957 borsato, a., frisia, s., fairchild, i.j., somogyi, a. & susini, j. (2007): trace element distribution in annual stalagmite laminae mapped by micrometer-resolution x-ray fluorescence: implications for incorporation of environmentally significant species.– geochim. cosmochim. ac., 71/6, 1494–1512. doi: 10.1016/j.gca.2006.12.016 cheng, h., spötl, c., breitenbach, s.f.m., sinha, a., wassenburg, j.a., jochum, k.p., scholz, d., li, x., yi, l., peng, y., lv, y., zhang, p., votintseva, a., loginov, v., ning, y., kathayat, g. & edwards, r.l. (2016): climate variations of central asia on orbital to millennial timescales.–sci. rep., 6, 1–11. doi: 10.1038/ srep36975 collister, c. & mattey, d. (2008): controls on water drop volume at speleothem drip sites: an experimental study.– j. hydrol., 358/3–4, 259–267. doi: 10.1016/j.jhydrol.2008.06.008 day, c.c. & henderson, g.m. (2013): controls on trace-element partitioning in cave-analogue calcite.– geochim. cosmochim. ac., 120, 612–627. doi: 10.1016/j.gca.2013.05.044 drysdale, r.n., hellstrom, j.c., zanchetta, g., fallick, a.e., sánchez goñi, m.f., couchoud, i., mcdonald, j., maas, r., lohmann, g. & isola, i. (2009): evidence for obliquity forcing of glacial termination ii.– science, 325/5947, 1527–1531. doi: 10.1126/ science.1170371 fairchild, i.j., borsato, a., tooth, a.f., frisia, s., hawkesworth, c.j., huang, y., mcdermott, f. & spiro, b. (2000): controls on trace element (sr-mg) compositions of carbonate cave waters: implications for speleothem climatic records.– chem. geol., 166, 255–269. doi: 10.1016/s0009-2541(99)00216-8 fairchild, i.j. & treble, p.c. (2009): trace elements in speleothems as recorders of environmental change.– quaternary sci. rev., 28/5–6, 449–468. doi: 10.1016/j.quascirev.2008.11.007 frisia, s., fairchild, i.j., fohlmeister, j., miorandi, r., spötl, c. & borsato, a. (2011): carbon mass-balance modelling and carbon isotope exchange processes in dynamic caves.– geochim. cosmochim. ac., 75/2, 380–400. doi: 10.1016/j.gca.2010.10.021 gabrovšek, f. (2023): how do caves breathe: the airflow patterns in karst underground.– plos one, 18/4, e0283767. doi: 10.1371/journal.pone.0283767 johnson, k.r., hu, c., belshaw, n.s. & henderson, g.m. (2006): seasonal trace-element and stable-isotope variations in a chinese speleothem: the potential for high-resolution paleomonsoon reconstruction.– earth planet. sc. lett., 244/1–2, 394–407. doi: 10.1016/j.epsl.2006.01.064 kukuljan, l., gabrovšek, f. & covington, m.d. (2021): the relative importance of wind-driven and chimney effect cave ventilation: observations in postojna cave (slovenia).– int. j. speleol., 50/3, 275–288. doi: 10.5038/1827-806x.50.3.2392 lyu, y., luo, w., wang, y., zeng, g., chen, j. & wang, s. (2023): response of drip water mg/ca and sr/ca variations in ventilated caves to hydroclimate. sci.– total environ., 874, 162626. doi: 10.1016/j.scitotenv.2023.162626 magyar, i., geary, d.h. & müller, p. (1999): paleo-geographic evolution of the late miocene lake pannonian in central europe.– palaeogeogr. palaeocl. palaeoeco., 147, 151–167. doi: 10.1016/s00310182(98)00155-2 mattey, d.p., fairchild, i.j., atkinson, t.c., latin, j.p., ainsworth, m. & durell, r. (2010): seasonal microclimate control of calcite fabrics, stable isotopes and trace elements in modern speleothem from st michaels cave, gibraltar.– in: pedley, h.m. & rogerson, m. (eds.): tufas and speleothems: unravelling the microbial and physical controls. geological society, london, special publications, 336, 323–344. doi: 10.1144/sp336.17 mcdonald, j., drysdale, r. & hill, d. (2004): the 2002–2003 el niño recorded in australian cave drip waters: implications for reconstructing rainfall histories using stalagmites.– geophys. res. lett., 31, 1–4. doi: 10.1029/2004gl020859 mickler, p.j., banner, j.l., stern, l., asmerom, y., lawrence edwards, r. & ito, e. (2004): stable isotope variations in modern tropical speleothems: evaluating equilibrium vs. kinetic isotope effects.– geochim. cosmochim. ac., 68/21, 4381–4393. doi: 10.1016/j. gca.2004.02.012 nava-fernandez, c., hartland, a., gázquez, f., kwiecien, o., marwan, n., fox, b., hellstrom, j., pearson, a., ward, b., french, a., hodell, d.a., immenhauser, a. & breitenbach, s.f.m. (2020): pacific climate reflected in waipuna cave dripwater hydrochemistry.– hydrol. earth syst. sc., 24/6, 3361–3380. doi: 10.5194/hess-24-3361-2020 peel, m.c., finlayson, b.l. & mcmahon, t.a. (2007): updated world map of the köppen-geiger climate classification.– hydrol. earth syst. sc., 11/5, 1633–1644. doi: 10.5194/hess-11-1633-2007 r core team (2024): r: a language and environment for statistical computing. r foundation for statistical computing, vienna, austria. https:// www.r-project.org/ van rampelbergh, m., verheyden, s., allan, m., quinif, y., keppens, e. & claeys, p. (2014): monitoring of a fast-growing speleothem site from the han-sur-lesse cave, belgium, indicates equilibrium deposition of the seasonal δ18o and δ13c signals in the calcite.– clim. past, 10/5, 1871–1885. doi: 10.5194/cp-10-1871-2014 riechelmann, d.f.c., riechelmann, s. & schröder-ritzrau, a. (2022): long-term elemental trends in drip waters from monitoring bunker cave: new insights for past precipitation variability.– chem. geol., 590, 120704. doi: 10.1016/j.chemgeo.2021.120704 sinclair, d.j., banner, j.l., taylor, f.w., partin, j., jenson, j., mylroie, j., goddard, e., quinn, t., jocson, j. & miklavič, b. (2012): magnesium and strontium systematics in tropical speleothems from the western pacific.– chem. geol., 294–295, 1–17. doi: 10.1016/j. chemgeo.2011.10.008 spötl, c., fairchild, i.j. & tooth, a.f. (2005): cave air control on dripwater geochemistry, obir caves (austria): implications for speleothem deposition in dynamically ventilated caves.– geochim. cosmochim. ac., 69/10, 2451–2468. doi: 10.1016/j.gca.2004.12.009 surić, m., lončarić, r., bočić, n., lončar, n. & buzjak, n. (2018): monitoring of selected caves as a prerequisite for the speleothembased reconstruction of the quaternary environment in croatia.– quatern. int., 494, 263–274. doi: 10.1016/j.quaint.2017.06.042 surić, m., columbu, a., lončarić, r., bajo, p., bočić, n., lončar, n., drysdale, r.n. & hellstrom, j.c. (2021): holocene hydroclimate changes in continental croatia recorded in speleothem δ13c and δ18o from nova grgosova cave.– the holocene, 31/9, 1401– 1416. doi: 10.1177/09596836211019120 šikić, k., basch, o. & šimunić, a. (1978): osnovna geološka karta sfrj 1:100000, list zagreb l33–80 [basic geological map of sfry 1:100.000, the zagreb sheet l33–80 – in croatian].– institut za geološka istraživanja zagreb (1972), savezni geološki zavod, beograd. šikić, k., basch, o. & šimunić, a. (1979): osnovna geološka karta sfrj 1:100000. tumač za list zagreb l33–80 [basic geological map of sfry 1:100000, geology of the zagreb sheet – in croatian].– institut za geološka istraživanja zagreb (1972), savezni geološki zavod, beograd, 81 p. g eologia c roatica 251bajo et al.: seasonality in cave dripwater and air properties – implications for speleothem palaeoclimatology, nova grgosova cave (croatia) tadros, c.v., treble, p.c., baker, a., fairchild, i., hankin, s., roach, r., markowska, m. & mcdonald, j. (2016): ensocave drip water hydrochemical relationship: a 7-year dataset from southeastern australia.– hydrol. earth syst. sc., 20/11, 4625–4640. doi: 10.5194/hess-20-4625-2016 tadros, c.v., treble, p.c., baker, a., hankin, s. & roach, r. (2019): cave drip water solutes in south-eastern australia: constraining sources, sinks and processes.– sci. total environ., 651, 2175–2186. doi: 10.1016/j.scitotenv.2018.10.035 tomljenović, b. & csontos, l. (2001): neogene–quaternary structures in the border zone between the alps, dinarides and pannonian basin (hrvatsko zagorje and karlovac basin, croatia).– int. j. earth. sci., 90, 560–578. doi: 10.1007/s005310000176 tooth, a.f. & fairchild, i.j. (2003): soil and karst aquifer hydrological controls on the geochemical evolution of speleothem-forming drip waters, crag cave, southwest ireland.– j. hydrol., 273/1–4, 51–68. doi: 10.1016/s0022-1694(02)00349-9 treble, p.c., shelley, j.m.g. & chappell, j. (2003): comparison of high resolution sub-annual records of trace elements in a modern (1911– 1992) speleothem with instrumental climate data from southwest australia.– earth planet. sc. lett., 216/1–2, 141–153. doi: 10.1016/s0012821x(03)00504-1 treble, p.c., fairchild, i.j., griffiths, a., baker, a., meredith, k.t., wood, a. & mcguire, e. (2015): impacts of cave air ventilation and in-cave prior calcite precipitation on golgotha cave dripwater chemistry, southwest australia.– quaternaty sci. rev., 127, 61–72. doi: 10.1016/j.quascirev.2015.06.001 treble, p.c., baker, a., abram, n., hellstrom, j.c., crawford, j., gagan, m., borsato, a., griffiths, a., bajo, p., markowska, m., priestley, s., hankin, s. & paterson, d. (2022): ubiquitous karst hydrological control on speleothem oxygen isotope variability in a global study.– commun. earth. environ. 3, 29. doi: 10.1038/s43247-022-00347-3 tremaine, d.m. & froelich, p.n. (2013): speleothem trace element signatures: a hydrologic geochemical study of modern cave dripwaters and farmed calcite.– geochim. cosmochim. ac., 121, 522–545. doi: 10.1016/j.gca.2013.07.026 vrsaljko, d., pavelić, d. & bajraktarević, z. (2005): stratigraphy and palaeogeography of miocene deposits from the marginal area of žumberak mt. and the samoborsko gorje mts. (northwestern croatia).– geol. croat., 58/2, 133–150. doi: 10.4154/gc.2005.07 warken, s.f., fohlmeister, j., schröder-ritzrau, a., constantin, s., spötl, c., gerdes, a., esper, j., frank, n., arps, j., terente, m., riechelmann, d.f.c., mangini, a. & scholz, d. (2018): reconstruction of late holocene autumn/winter precipitation variability in sw romania from a high-resolution speleothem trace element record.– earth planet. sc. lett., 499, 122–133. doi: 10.1016/j.epsl.2018.07.027 wassenburg, j.a., riechelmann, s., schröder-ritzrau, a., riechelmann, d.f.c., richter, d.k., immenhauser, a., terente, m., constantin, s., hachenberg, a., hansen, m. & scholz, d. (2020): calcite mg and sr partition coefficients in cave environments: implications for interpreting prior calcite precipitation in speleothems.– geochim. cosmochim. ac., 269, 581–596. doi: 10.1016/j.gca.2019.11.011 wong, c.i., banner, j.l. & musgrove, m. (2011): seasonal dripwater mg/ca and sr/ca variations driven by cave ventilation: implications for and modeling of speleothem paleoclimate records.– geochim. cosmochim. ac., 75/12, 3514–3529. doi: 10.1016/j.gca.2011.03.025 wortham, b.e., montañez, i.p., bowman, k., kuta, d., contreras, n.s., brummage, e., pang, a., tinsley, j. & roemer-baer, g. (2021): monitoring of sierra nevada caves reveals the potential for stalagmites to archive seasonal variability.– front. earth sci., 9, 781526. doi: 10.3389/feart.2021.781526 (2024) croatian meteorological and hydrological service – cmhs, meteorological data sets. electronic supplementary material is available online at http://www.geologia-croatica.hr/index.php/gc/article/view/1231/1963 2022 | 75/1 | 17–33 | 16 figs. | 2 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction in the literature, the most used definition of a landslide is a mass of rock movement, of debris or earth down a slope under gravity (cruden & varnes, 1996). intensive rainfall, earthquakes, and human activities are the main triggering factors of slope failure, whereas the occurrence of a landslide is controlled by different factors such as geology and geomorphology as the most important ones (van westen et al., 2008). landslide processes can be better understood by preparing landslide inventory maps (soeters & van westen, 1996; fell et al., 2008; ghosh et al., 2012). landslide inventory maps document the extent of landslide phenomena in a region and show information about the distribution, types, pattern, recurrence, and statistics of slope failures (guzzetti, et al. 2012). it is important to prepare inventory maps for areas where landslides are frequent and abundant, and where slope failures are sparse or rare (van den eeckhaut et al., 2007) so landslide susceptibility, hazard, and risk at the regional, national and continental scales could be determined more accurately (brabb et al., 2000). an overview of traditional techniques and recent developments for landslide inventory mapping is given by van westen et al. (2008) and guzzetti et al. (2012). one of the recently most critical techniques of landslide investigation includes the use of airborne light detection and ranging (lidar) method. lidar is used to create accurate and precise high-resolution digital elevation models (hr a case study in the research polygon in glina and dvor municipality, croatia-landslide susceptibility assessment of geological units marina filipović*, ivan mišur, vlatko gulam and marija horvat croatian geological survey, sachsova 2, hr-10000 zagreb, croatia; (*corresponding author: mfilipovic@hgi-cgs.hr) doi: 10.4154/gc.2022.04 abstract in this paper, a preliminary analysis of the landslide inventory is presented for the wider area of the municipalities of glina and dvor, within sisak-moslavina county in croatia, where lidar scanning for 45.85 km2 was conducted. landslide polygons were outlined based on the visual interpretation of hrdem derivates. in total, 477 landslides were contoured with an average landslide density of 9.85 per km2. most of the landslides are characterised as moderate, shallow, and not recent. the spatial relationship between landslides and geological units is expressed with the landslide index. subsequently, the geological units were grouped into four engineering geological units representing different susceptibilities to landslides. the geological units most prone to landslides are the eocene, oligocene, palaeocene and jurassic sandstones. even though all geological units were analysed here, the majority of landslides are within sandstones. a particular emphasis was on landslide occurrence in metamorphic and igneous rocks of the ophiolite sequence, a distinctive characteristic of the research area where less susceptibility to landslide processes was observed. moreover, to further distinguish the differences between the units in the area a morphometric characteristic (relief) and drainage network was also analysed. the purpose of this analysis was to additionally confirm the landslide susceptibility assessment and the division of geological units into engineering geological units, which again implied the different behaviours between landslides in igneous and metamorphic rocks compared to sandstones. because the research area is poorly studied regarding landslide susceptibility, relief, and drainage networks, these findings will be a step forward in recognising the relationship between them and creating a base for the development of a landslide susceptibility map for this area. the most common definition of a landslide is movement of a mass of rock, debris, or earthdown a slope under gravily (1996) dem) in raster grid representations of the topography or true 3d point clouds with a high density of information (jaboyedoff et al., 2010) in the geographic information system (gis) environment. as field reconnaissance is time-consuming, hrdem derivates enable desktop mapping of landslides to be far more manageable, faster, and more precise (van westen et al., 2008; guzzetti et al. 2012). moreover, advances in gis technology have solved the problem of showing multiple forms of landslide information on one map (guzzetti et al., 2012). these new and emerging mapping methods have greatly facilitated the production and updating of landslide maps (guzzetti et al., 2012). this highly detailed topographic data enables interpretation of the morphological features, often associated with landslides and allows us to overcome a major limitation of mapping from aerial imagery since the morphology beneath the forest cover can be observed (van den eeckhaut et al., 2007). all of this information can later serve as an input for the development of landslide susceptibility maps (lsm). various methods and procedures have been described in the literature, explaining the basic principles and techniques to evaluate landslide susceptibility and evaluate the hazards posed therein (ahmed et al., 2014). it is rarely the case where all of the existing methods in the literature are applied during the creation of lsm because such analyses depend upon the quality and resolution of available data. based on a review of published literature (hutchinson, article history: manuscript received april 02, 2021 revised manuscript accepted september 13, 2021 available online february 28, 2022 keywords: inventory map, landslide susceptibility assessment, engineering-geological units, lidar, hrdem, dvor and glina municipality, croatia g eo lo gi a c ro at ic a 18 geologia croatica 75/1 1995; van westen et al., 1997; guzzetti et al., 1999) lsm’s categorised according to various criteria and always denoted as being quantitative or qualitative, direct or indirect, heuristic, probabilistic or deterministic, for differentiated or undifferentiated types of landslide mechanism (ahmed et al., 2014, peshevski et al., 2019). within project safearth (transnational advanced management of land use risk through landslide susceptibility maps design), carried out from 2017 to 2019 under the interreg ipa cross-border cooperation programme croatia-bosnia and herzegovina-montenegro 2014-2020, six polygons covering an area of approximately 310 km2 were scanned using lidar. in this paper, research results of one of the pilot areas in sisak-moslavina county covering 45.85 km2 is presented. bearing in mind that the research polygon is located in the municipalities of dvor and glina areas, where many people were displaced by the events of the independence war in croatia (1991-1995), large parts of the terrain are inaccessible and overgrown by vegetation, so the use of airborne laser scanning flights (lidar) was requisite. furthermore, a scanned polygon in the study area was chosen due to characteristic geological features since a considerable part of the lithological units in the area is composed of metamorphic and igneous rocks, covering more than 20 % of the research area. the other parts of the terrain, mostly covered with sedimentary rocks, have also been a part of this study. therefore, a landslide inventory by visually analysing hrdem derivatives from lidar were made for this area for the first time. the main goal of this paper is to determine the influence of lithology, extracted from the geological map of sisak-moslavina county in the scale of 1:100 000 (hećimović & avanić, 2014), on the spatial distribution of landslides and to analyse geometric characteristics in different geological units (gu). additionally, the relationship between geomorphological properties (i.e. relief), drainage density, and spring occurrence (extracted from the topographical map on the scale of 1:25 000 in areas where multiple springs appear) with the occurrence of landslides within different gu’s was also examined. also, a microscopic analysis was made to determine the major mineral composition of rocks and alteration processes caused by weathering, which consequently can lead to soil instabilities causing landslides. furthermore, to deal with this great variety of sources prepared at different scales, a large part of the work included homogenising the data in a gis environment (lucianetti et al, 2019). as a result of these analyses, a landslide susceptibility assessment of gu’s was made by grouping them into 4 geological engineering units (egu). 2. study area description 2.1. study area the investigated area is located in sisak-moslavina county, northwest of the city of glina and southeast of the city of dvor (figure 1). the area is positioned in the zrinska gora mt. surrounded by the una river to the east, the sava river to the south, and the kupa river to the north, while in the west, it borders with the bosnia and herzegovina. the mountain has a very developed relief with steep slopes and deeply incised stream valleys. the study area comprises 48.45 km2 with the lowest elevation point at 167 metres a.s.l. and the highest at 552 m.a.s.l. around 25 % of the area is in an elevation category ranging from 201-300 m.a.s.l., whereas 40 % of the investigated area belongs to the elevation category ranging from 301-400 m.a.s.l., and 30 % of the area is in the category from 401-500 m.a.s.l. only 4 % of the area is in elevation category 167-200 m.a.s.l., and 2 % in elevation category 501-552 m. according to slope classification by demek (1972), more than half of the terrain (54 %) belongs to very sloping terrain and sloping terrain (24 %), whereas 13 % can be classified as very steep. 6 % of the area is slightly sloping terrain, and only 2 % of the area is plain. the research area belongs to the geomorphological region of the pannonian basin, where hills/mountains of the broader research polygon belong to a micro-geomorphological region (bognar, 2001). neogene and quaternary regional uplift elevated the area for approximately 500 m (čubrilović et al., 1967) causing the formation of relief of high erosive energy. therefore, the investigated polygon is characterised by a branched relief. major watercourses of the zrinska gora mt. are the sunja, petrinjčica, žirovac (žirovnica), maja, and utinja streams, while in the research area, the primary streams are the žirovac and its tributary stupnica, which have their confluence with the una river near the city of dvor. according to the köppen & wegener (1924) classification, šapić (2012) characterised the climate of this area as a moderately warm and wet. this type of climate is characterised by small amounts of precipitation during the winter, but without a dry period during the whole year. according to the thornthwaithe (1931) classification, the investigated area belongs to the humid climate area. the lowest central air temperature is during january, while the highest is in july. data taken from meteorological stations in the vicinity show that the average annual precipitation is approximately 1000 mm and is equally distributed in all stations. the driest month is february, while the highest rainfall period is during september and november (pintarić, 2020). the predominant vegetation is beech, sessile oak, hornbeam, and chestnut forests, while grasslands, meadows, and pastures cover the remaining area. half of the research polygon belongs to the municipality of dvor, and half to the municipality of glina. in the nearby area, several smaller villages are still inhabited. as already mentioned in the previous section, unfortunately during the croatian war of independence, the area was deserted, and the population in these settlements has been significantly reduced. most households are empty, and access roads are covered with vegetation making it difficult to move around. despite the small population, several landslides have been reported in this area, especially during the 2014 and 2018 weather extremes. this was also one of the reasons why this research polygon was chosen for lidar scanning. 2.2. geological setting zrinska gora mt. represents an extension of the sana-una unit and belongs to the inner dinarides (nenadić et al., 2010). the geology of the zrinska gora mt. is heterogeneous and complex. most of the zrinska gora mt. is composed of eocene flysch and the igneous-sedimentary complex of jurassic and lower cretaceous age. the central part of zrinska gora mt. (šamarica and the surrounding hills) comprises palaeogene deposits. the categorisation is based on chronostratigraphic division and labelled as gu’s, 1 12, except for ββ which is lithostratigraphic category (table 1, figure 1). the most dominant lithological members of these units will be emphasised in section 3.2. in the map legend, units m2 and k2 3 do not have a number and are not a part of the analysis because they are outside the lidar scanned area. 3. methods and materials factors responsible for landslide occurrence can be divided into controlling and triggering factors. slope failures can be triggered g eologia c roatica 19filipović et al.: a case study in the research polygon in glina and dvor municipality, croatia-landslide susceptibility assessment of geological units figure 1. geological map of the investigated area (hećimović & avanić, 2014), with the sites of engineering-geological observations (labelled mf) and sampling points for mineralogical-petrographic analyses (labelled mvim) marked. g eo lo gi a c ro at ic a 20 geologia croatica 75/1 by rainfall, earthquakes, volcanic eruptions, and manmade activities. e.g. clear-cutting (papathanassiou et al., 2021), whereas controlling factors can be represented by relevant thematic maps using gis techniques (moradi & rezaei, 2014). many landslide susceptibility studies focus on the identification of those parameters or variables that generally control the slope instability of a given area. controlling variables can be identified by gathering the available geomorphological and environmental factor maps across the study area (ahmed et al., 2014). the first step for examining the correlation of the characteristics of the landslide occurrence, for example the landslide area with the controlling factors, is to develop an inventory map where all slope failures are reported (papathanassiou et al., 2021). therefore, the mein topic of this paper is analysis of lidar data and afterwards preparation of hrdem derivates and finally, development of a landslide inventory. further on, the research focuses on the correlation of a landslide inventory with: i) geology/lithology ii) relief and iii) drainage network. spring analysis was also considered during the analyses but only within gu 12, where multiple springs appear. the data used to prepare these layers were derived from topographic maps, geological maps, and hrdem at different scales as already previously mentioned. based on the analysis of these layers and field reconnaissance a categorization of lithological units into engineering geological units was made. the resultant statistical analysis and thematic maps represent a base for developing landslide susceptibility maps in the future. 3.1. landslide inventory the landslide inventory was derived from lidar post-processing hrdem data with a spatial resolution of 0.5 x 0.5 m. associated airborne laser scanning flights were undertaken in february and march 2018 by an external company fulfilling the requirements for at least 20 points per square metre and assuring the accuracy for each point of at most 10 cm in all directions. at the same time, topographic scanning was performed resulting in hr orthophotos with a 10 cm resolution. morphological terrain characteristics were explored in the arcgis 10.2.1 environment. lidar high-resolution digital terrain model (hrdem) derivates for interpretation of the main landslide features included: i) curvature map, ii) hillshade maps calculated with sun azimuth angles of 315⁰ and 45⁰, and the sun elevation angles of 45⁰, iii) slope map displayed in green to red colour ramp, iv) orthophotos with a spatial resolution of 10 cm and v) contour line map with the elevation equidistance of 10 m. furthermore, landslide polygons were outlined and the main landslide features were extracted by combining these derivates. landslide inventory was made based on visual interpretation and by combining the above-mentioned hrdem derivates. based on the experience in mapping landslides in other studies, a recommendation for using as many lidar derivates as possible, both singularly and in combinations, to recognise and precisely delineate the boundaries of individual landslide features is very important (jagodnik et al., 2020). during this process, landslides were graded in a range from one to ten. the given numbers were based on visual interpretation of several main landslide characteristics (varnes, 1978, van den eeckhaut et al., 2012): i) the main scarp located in the upper part of a landslide as a most important feature in landslide recognition, ii) the main scarp often transforms into the flanks, which represent the landslide edges and they usually appear perpendicular and downslope to the main scarp, iii) radial and transverse cracks in a landslide body area which often contain some minor scarps and usually appear very rough, iv) the landslide toe as a curved margin of the displaced material. therefore, number one represents a landslide with the least visible landslide features while number ten, is where almost all of the main landslide features are visible. furthermore, based on these landslide rankings (lr) three groups were formed: low lr (grades 1-3), moderate lr (grades 4-6), and high lr (7-10). additionally, because of the subdued morphological characteristics of some landslides, it is generally harder to consistently map landslides accurately. typically, these subdued characteristics are associated with older landslides (van den eeckhaut et al., 2007, petchko et al., 2016). hence, low grade landslides could therefore represent older landslides. figure 2. landslide polygon delineation using different dem derivates: a) curvature map, b) hillshade map with contour lines, c) slope map, d) orthophoto, e) hillshade map with a) low graded and b) high graded landslides. figure 3. landslide rankings visible on lidar hillshade derivates: a) high lr, b) moderate lr and c) low lr. g eologia c roatica 21filipović et al.: a case study in the research polygon in glina and dvor municipality, croatia-landslide susceptibility assessment of geological units two landslides, graded low (a) and high (b) are displayed in figure 2 and in figure 3. assessment of the corresponding lr is shown. figure 3a. shows high lr where most of the main landslide features are visible such as the main scarp, hummocky topography etc. and landslide contours are easily drawn. in figure 3b. moderate lr is presented, where the landslide main scarp and toe are clearly visible, but the borders of the landslide are not so clear and also the hummocky nature of the terrain is not so well emphasised. finally, in figure 3c. is an indication of the main scarp and toe, but it is difficult to follow the landslide contours. also, it is hard to distinguish other landslide main characteristics. 3.2. geology/lithology the geological map of the republic of croatia 1:300.000 reports that the oldest rock types in the investigated area belong to the upper palaeozoic complex (c, d); (šikić, 2009a). in presented study this rocks belongs to gu 12. the complex is described as a heterogenic flysch sequence, composed of low grade metamorphosed clastic sediments (slate, metasiltite, metasandstone, metaconglomerate) and carbonates (limestone and recrystallised limestone). the upper palaeozoic complex is mostly in tectonic contact with triassic rocks. the lower triassic (t1), gu 11, is represented by sandstone, siltstone, marl, and limestone, while the middle triassic (t2), gu 10, is represented by carbonates and occasionally marls. the upper triassic (t3), gu 9, is represented by various dolomites (sokač, 2009a,b). the jurassic lithology is composed of various igneous, sedimentary, and metamorphic rocks of middle to upper jurassic age as part of the ophiolitic-sedimentary complex (šikić, 2009b), called the “dinaridic ophiolite zone” (pamić et al., 1998) and in more recent literature the “western vardar ophiolitic unit” (schmid et al., 2008). the igneous rocks (j2,3) (šikić et al., 2009b), gu 8, are mainly altered lherzolites and harzburgites, pyroxenite, gabbro, dolerite diabase as smaller rock sections. hypabyssal (shallow intrusions) to effusive basic rocks (ββ), gu 6 are represented with diabase, basalt, and spilite diabase (i.e. spilites). the basalt bodies are most common and occasionally show pillow structures. the sedimentary rocks of the j2,3 (šikić et al., 2009b), gu 7, represent deep-sea facies, mainly sandstones, shales, and various silicic types (radiolarites, cherts), subordinate siltstones, limestones, and pyroclastic rocks. metamorphic rocks of j2,3, gu 7, are represented by varieties of metamorphosed basic igneous rocks and metamorphosed sedimentary rocks, mainly metapelites, metapsammites, metapsefites, subordinate recrystallised limestone, chert, and pyroclastic rocks (šikić, 2009c). the lower – upper cretaceous series (k1,2), gu 5, is represented by diverse clastic rocks, marls, limestones, and cherts (šikić & bergant, 2009; šparica et al., 2009). the palaeogene sequence (gu 3, 4) is represented by oligocene eocene, and palaeocene (ol, e, and pc) breccias, conglomerates, sandstones, siltites, shales and marls, and to a lesser extent limestones (šimunić, 2009). pliocene rock formations are mainly represented by lacustrine – fluvial clastic rocks interlayered with coal lenses (i.e. the “paludin beds” named by the genus of the lacustrine snail viviparus). to a lesser extent there are the fluvial-lacustrine clastic sediments of pliocene – pleistocene age (basch, 2009). typical quaternary deposits (hećimović, 2009) are pleistocene loess and various holocene clastic rocks, mainly gravel, sand, silt, and clay (gu 1). 3.3. landslide geometric analysis the geometric characteristics (shape, sizes) of landslides in this area within each gu were defined. information on the gu’s, with dominant lithology, of sisak-moslavina county at the scale of 1:100 000 were derived from the croatian geological survey (hećimović & avanić, 2014). landslide areas were derived automatically, whereas length and width ratios were extracted manually in the arcgis environment. landslide areas in square metres are shown with box and whisker plots. landslides are divided into five classes according to šestanović (2001): from very small (< 100 m), small (100 m – 1,000 m), moderate (1,000 m – 10,000 m), large (10,000 m – 50,000 m), and very large (> 50,000 m) landslides. basic statistical analysis of landslide cadastre data was made in arcgis 10.2.1 with analysis tools and excel 2016. the landslide width to length ratio is expressed with the landslide aspect ratio (la). according to the four-group classification of la, landslides are categorised as transverse (la≤0.8), isometric (0.8<la≤1.2), longitudinal (1.2<la≤3), and elongated (la>3) (tian et al., 2017). to compare the occurrence of landslides within different gu’s a landslide index (li) was calculated. the li was used to quantitatively define the strength of the relationship between the occurrence of landslides in different gu’s (lee & talib, 2005). the landslide index is expressed as the ratio in percentage between the landslide area and the area of each gu (conforti & ietto, 2020). consequently, the li can be used to quantitatively assess the landslide susceptibility of each gu. 3.4. relief analysis relief analysis is a numerical parameter determined by altitude difference between the highest and lowest points within the unit area and is calculated using the arcgis tool focal statistics. the radius of a circle taken around each cell to calculate the elevation range is set to 240 m. the radius was chosen based on the approximate average slope length in the study area. in the local context, relief is conditioned by the specifics of the terrain and represents a parameter of the intensity of the development of exogenous processes (gerić, 2019). landslides, as any geological phenomena, are formed due to the simultaneous action of exogenous and endogenous forces (niyazov & nurtaev, 2017). in areas with higher relief, the intensity of erosion is higher, and in areas with lower relief, there is an increased accumulation of material. therefore, maximum and minimum values represent the most unstable parts of the terrain, i.e. areas of the largest sediment concentrations. therefore, this analysis was made because relief is considered one of the essential parameters influencing landslide occurrence. regionally, relief reflects the youngest tectonic movements (lozić, 1995). a map of the relief provides an evaluation of tectonic uplift and fluvial erosive action (conforti & ietto, 2020). it is important to highlight that the interpretation of relief is always better when the influence of lithological composition on the erosion intensity and accumulation is determined (marković, 1983). relief is categorised based on the natural breaks (jenks) algorithm in 5 classes as follows: 13-66 m (very low relief), 67-91 m (low relief), 92-116 m (moderate relief), 107-147 m (high relief) and 147-215 m (very high relief). the jenks natural breaks classification method was useful for comparing multiple maps created from different underlying information, giving the best group similar values and maximising the differences between classes (zhou et al, 2016). 3.5. drainage network and spring features drainage provides a basis for understanding the initial gradient, variation in rock resistance, geological and geomorphologic hisg eo lo gi a c ro at ic a 22 geologia croatica 75/1 tory of the drainage basin, or watershed (kumar et al., 2017). to improve the knowledge between slope and fluvial processes (ng, 2006), the drainage network was manually extracted using a topographic map of croatia at the scale of 1:25 000. moreover, some additional watercourses were added from hrdem hillshade substrates. drainage density is an important aspect of the drainage network composition, which measures the degree of drainage development within a region (horton, 1945). in areas close to streams, water erosion processes often cause slope undercutting, which often leads to landslides. furthermore, debris and soil materials close to water bodies are prone to collapse during heavy rainfall (bathrellos et al., 2009). a drainage density map was produced using the line density tool in the arcgis spatial analyst tools to see how the formation of watercourses affects the occurrence of landslides in different gu’s. additionally, the distance to springs was also taken into consideration during the description of gu 12 behaviour, concerning the occurrence of landslides. four categories representing low to high drainage density (i-iv) are extracted based on the jenks natural breaks algorithm. category 0 is also shown on the map and in the graphs but due to the great distance from landslides was not processed. 3.6. field recognition and verification field campaigns included landslide recognition and verification of the landslide inventory in each geological unit in the research polygon (figure 4). identification of landslides from lidar derivatives is verified with several field recognitions. landslide inventory data can be seen in figure 1. in october and november of 2019, the first two campaigns were focused on the processes in metamorphic and igneous rocks of the research area. during the remaining field campaigns (march and april of 2020), landslide verification was made for the rest of the lithological units of the research polygon. this research aimed to determine the depth of regolith, mineralogical and granulometric material composition using terrain methods. according to the oxford dictionary of earth sciences (allaby & allaby, 2003), regolith is a figure 4. field verification and an example of the terrain determination of the depth of regolith and granulometric composition (gu 11). figure 5. left: photo of the outcrop of sample mvim32. right: photomicrograph of sample mvim32 under polarised light (a) and (b) with crossed polars. g eologia c roatica 23filipović et al.: a case study in the research polygon in glina and dvor municipality, croatia-landslide susceptibility assessment of geological units layer of unconsolidated weathered material, including rock fragments, mineral grains, and all other superficial deposits on unaltered solid bedrock. 3.7. analysis of the rock samples during the field investigations, 34 rock samples were collected, from which 17 samples labelled mvim (28 thin sections) were selected for micropetrographic analysis (figures 1 and 5). macroscopic and microscopic observations were performed at the croatian geological survey to determine the textural and structural features and mineralogical composition of the rock samples and alteration processes. photomicrographs were taken with a zeiss axio lab. a1 hal 35 and a5 petrographic microscopes equipped with a digital camera. 4. results 4.1. landslide geometric analysis the landslide inventory map was composed for an area of 48.45 km2 in sisak-moslavina county. a total of 477 landslides were recognised, comprising an area of 2.32 km2 (4,8%). subsequently, the inventory analysis showed that the average number of landslides per km2 is 9.85 for the total area. twelve different gu’s are registered. in table 1 a general overview of the main statistical parameters is given. it is evident that in gu’s a, ap (gu 1); pl, q (gu 2), and t2 (gu 10) landslides are not registered. in gu 1 alluvium deposits represent the youngest part of the terrain where sediments that have been eroded by water are redeposited in the lowest part of the terrain. less than 1 % of the area within gu 2 and gu 10 is covered with lidar scan therefore, the absence of landslides was expected. hence, some of the gu areas have less than 1 % of the area covered with landslides (c, d (gu 12); t1 (gu 11), and k1,2 (gu 5)). on the other hand, in some of the gu’s (j2,3_f (gu 8) and ββ (gu 6)), where more of the surface was detected with lidar scanning, landslide areas range from 1% to 2 %. gu, where the highest number of landslides were recorded, are j2,3 (gu7); pc (gu 4), and e, ol (gu 3). looking at the size of the landslides polygons, four groups of similar size ranges prevail (figure 6). average sizes range from 2700 m2 to 3500 m2 and belong to gu 5 and gu 8. the second groups are gu 3 and gu 4, where the average size is around 5700 m2. the third group consists of gu 4 and gu 7 with average sizes of around 6500 m2. the fourth group (gu 9 and gu 12) table 1. summary table of landslide distribution. chronostratigraphic division geological unit geological unit area [km2] geological unit area [%] no. of landslides landslide area [km2] landslide area [%] landslide distribution [%] no. of landslides per km2 a, ap 1 1.10 2.26 pl, q 2 0.04 0.08 e, ol 3 8.47 17.49 177 0.86 10.11 1.77 20.89 pc 4 1.80 3.72 17 0.09 4.78 0.18 9.43 k1,2 5 1.86 3.83 6 0.01 0.41 0.02 3.23 ββ* 6 1.62 3.34 16 0.03 1.63 0.05 9.88 j2.3_s 7 14.82 30.59 190 1.06 7.17 2.19 12.82 j2.3_f 8 8.57 17.70 49 0.12 1.42 0.25 5.71 t3 9 2.25 4.64 10 0.09 4.00 0.19 4.45 t2 10 0.25 0.51 t1 11 1.35 2.78 1 0.01 0.38 0.01 0.74 c, d 12 6.32 13.04 11 0.06 0.92 0.12 1.74 *lithological classification figure 6. area of mapped landslides for each geological unit. legend for each geological unit is presented in table 1. g eo lo gi a c ro at ic a 24 geologia croatica 75/1 has the highest average size for landslides ranging from 8000 m2 to 9200 m2. according to šestanović (2001), all landslides in this polygon are considered moderate in size. it is also important to emphasise that maximum landslide sizes within all gu range from 13000 m2 to 43000 m2. they are categorised as large, according to the scale mentioned above, except for the largest landslide (104440 m2) in the polygon belonging to gu 3 which is categorised as very large. the smallest landslide (89 m2) belongs to gu 7. looking at figure 6 it can be seen that only a few very small landslides (<100 m2) are mapped. moreover, landslide shapes and sizes (figure 7) also show that most of them are longitudinal with an average length of 132 m and width of 51 m, which results in la 2.58. only in gu’s 3 and 4 do average la values exceed 3 and landslides are characterised as elongated. nevertheless, the mean values within these units are slightly below 3. for all other gu units, values are between 2.5 and 2.8, so they are considered longitudinal. field prospection, which also included landslide verification, gave insight into shallow soil slides prevalent in most gu’s. understanding this specific type of landslide mechanism could be dependent on the composition of land sliding material, which was identified during terrain observations as a mix of coarse-grained dust, sand, gravel, and often containing bedrock fragments. moreover, underlining bedrock material is 0.5 to max 1.5 metres below the shallow regolith in all gu’s of the research area. 4.2. landslide index the landslide index (li), expressed as the ratio in percentage between the landslide area and the area of each lithology class in the researched polygon, shows values from a maximum of 10 %, figure 7. hillshade map derived from the dtm with an azimuth angle of 315⁰ with landslide inventory of characteristic landslides in different gu’s: a) conglomerate, sandstone, marl, clay and coal (eocene), b) sandstone, shale and flysch marls (paleocene), c) sandstone, shale and limestone (cretaceous) d) diabase and spilite (jurassic) e) sandstone, shale and chert (jurassic) f ) schist, phyllites, serpentinites and amphibolites (jurassic) g) dolomites (triassic) h) shale and sandstone with limestone traces (carboniferous, devonian). figure 8. areal distribution of landslides compared to the lithologies of different gu’s. legend in table 1. g eologia c roatica 25filipović et al.: a case study in the research polygon in glina and dvor municipality, croatia-landslide susceptibility assessment of geological units 7 %, 5 % for the three gu’s mainly consisted of sandstones (gu 3; gu 7; gu 4) (figure 8). in gu 9 the li is around 4 %. the dominant lithology in gu 9 is dolomite, so these values are quite unexpected. from the map (marked yellow polygon in figure 1 with symbol a), it is notable that unit gu 9 is in contact with gu 5 where once again the dominant lithology is sandstone. given the scale of the map used in this analysis, it is more likely that the geological boundary is not entirely accurate and that the landslides are developed in sandstone regolith that is hypsometrically above the dolomites. lower values of li around 1.5 % are recorded for igneous and metamorphic rocks (gu 8 and gu 6). the lowest values of li are below 1 %, and they are observed for limestone, dolomite, sandstone and shale deposits (gu 10; gu 11 and gu 12). from figure 9 it can be seen that more than 60 % of all of the landslides in our research polygon are classified in the low lr range. gu’s 1, 2 and 10 are omitted from the graph because no landslides were recorded there. the average grade for all of the gu’s presented in this area is 2.7. according to the average grades, it could be concluded that the landslides on the investigated polygon are characterised by ambiguous landslide main features (varnes, 1978), which may be an indication of older landslides. gu’s mostly composed of sandstones, in this case, gu 3 and gu 7, have the most significant number of landslides in the third, high lr category, around 10 %. also, moderate lr in these gu’s is present (30%). the gu consisting primarily of metamorphic rocks (gu 8) has around 35 % of landslides in the second category and only 5 % of landslides are categorised in the high lr range. gu 6, gu 9, and gu 12 have 10 % of landslides in the moderate lr range and less than 5 % of landslides in the high lr range. 4.3. relief analysis the map of the morphometric parameter concerning relief is given in figure 10. the general conclusion is that the research area is characterised by geomorphological heterogeneity. the first category has the lowest relief values ranging from 13-66 m which are mostly observed on floodplains and gently sloping terrain. the second category curve grows from 67-91 m, where gently sloping terrain is also observed. in the third category, values figure 9. landslide ranking (lr) within each gu with mapped landslides. legend in table 1. figure 10. relief map with gu’s from 1-12. g eo lo gi a c ro at ic a 26 geologia croatica 75/1 range from 92-116 m. in this moderate relief category, slightly steeper terrain is observed. the fourth, high relief category ranging from 117-147 m, indicates steep terrain. the fifth and very high relief category (148-215 m) show a very high energy terrain, with steep slopes and deeply incised valleys. in the fourth and fifth categories, and also in part of the third relief category, higher values are an indication that the area is characterised by hard rocks and deep incised, narrow valleys. from the values of relief categories in the various gu’s, several differences could be distinguished. gu 1 and 2 are only represented in the first three categories with average relief values of around 80 m. gu 1 has a maximum value of 143 m even though its geological setting implies that the terrain should be plain, but due to the scale of the geological map, i.e. geological boundaries positioning, these values could be expected. sandstones from gu 2 and 4 in comparison to sandstones from gu 7 have slightly lower relief values. the average relief values in gu 3 are 100 m with a maximum of 171 m. the average values for gu 4 are 90 m, and the maximum is 128 m. the average values of all other gu’s range from 100-120 m except for gu 11, with an average value of 138.5 m and a maximum of 215 m. the maximum values of gu 7, 8, 9, 10 are around 200 m. maximum values for gu 3, 5, and 12 are slightly lower, around 170 m, and gu 4 is around 130 m. minimal values are ranging from 13 m to even 60 metres. figure 11a shows that all categories are present within gu’s which cover the highest areas of the investigated polygon. nevertheless, within gu’s 6, 7, 8, 11, 12, higher categories dominate lower ones. this indicates the prevalence of harder rock materials and older geology. from figure 11b it can be seen that in gu’s 1, 2, more than 70 % of the surface is accounted for in the first figure 11. relief categories (i-very low relief, ii-low relief, iii-moderate relief, iv-high relief, and v-very high relief) within all gu’s in square km (a) and percentages (b). legend for each geological unit is presented in table 1. figure 12. relief categories (i-very low relief, ii-low relief, iii-moderate relief, iv-high relief, and v-very high relief) within all gu’s with mapped landslides in square km (a) and percentages (b). legend for each geological unit is presented in table 1. g eologia c roatica 27filipović et al.: a case study in the research polygon in glina and dvor municipality, croatia-landslide susceptibility assessment of geological units two categories. in contrast, more than 65 % of gu 3, 4, and 5 is in the second and third category, and less than 15 % is in the fourth category. for gu 6 and 11, 90 % of the area is in the last three categories. more than 65 % of gu’s 7, 8, and 12 are in the second, third, and fifth categories. in gu 9, 85% of the area is in the first two categories. figure 12 shows landslide areas within different relief categories among gu’s. it is evident that in gu’s where the largest number of landslides are recorded almost all relief categories are present (figure 12a). nevertheless, the predomination of categories i, ii, and iii exists. from figure 12b it can be recognised that in gu 3, 28 % of the landslide area is in the first relief category and 33 and 36 % in the second and third categories respectively. for gu 7, 39 % is in category ii, 37 % in category iii, 14 % in category iv, and only 3 % in the last category. more than 80% of gu 8 and gu 12 are in categories ii, iii, and iv. in gu 5, 6 landslides are predominantly present in the last two categories (> 60 %). in gu 4, landslides are predominantly present in the third category. in gu 9 landslides are predominant in the first two categories, whereas in gu 11 one recorded landslide is in the fourth category. 4.4. drainage network drainage network morphological analysis provided an insight into the spatial distribution of landslides in the context of drainage network development in the different gu’s. extracted drainage network order and stream density are shown in figure 13. the investigation area has developed steeper and narrower incisions in places where the bedrock is closer to the surface. in places where sandstone rocks prevail, drainage networks are slightly wider. by visual checking, four individual basins (figure 13) are recognised in the research area, however complete catchments are not recorded with lidar, so it is assumed that this number is probably even higher. in figure 14, the spatial distribution of the drainage network categories within different gu’s is shown. it is noticed that in figure 13. stream network with manually extracted watercourses and calculated stream density (with line density tool in the arcgis spatial analyst tools) to examine the effect of watercourses on the occurrence of landslides in the various gus. figure 14. stream network drainage density from low to high (i-iv) different gus in square km (a) and percentages (b). legend for gus in table 1. g eo lo gi a c ro at ic a 28 geologia croatica 75/1 gu’s 3, 7, 8, and 12, all categories are present (figure 14a). from figure 14b, it is observable that in gu 3 more than 50 % of the area is in the first two categories, whereas the second and third categories are equally distributed, only 11 % of the drainage area is in category iv. for gu 7 the first three categories are equally distributed throughout the whole area, and only 12 % of the area is in category iv. in gu 8 categories ii, iii, and iv are all almost equally distributed, whereas a slight domination of category iii with 38 % is seen. in gu 12 the first three categories are equally distributed and there is also a slight domination of category ii (40%) and the area in category iv accounts for 7 %. given the small distribution of areas from other gu’s, it is expected that the distribution of categories is not equal. in gu 5 all categories are visible, in gu 4, 6 and 9 first two categories are dominant and in gu 1 and 11 category ii and iii are dominant. looking at figure 15a gu 3 and gu 7, where dominant lithological units are sandstones, drainage density is much higher compared to other gu’s. in both gu 3 and 7, all categories are present but in different percentages (figure 15b). for gu 3 the first three categories have similar percentages, whereas the last category has a value of 7 %. geological unit 7 has similar values in the first two and last two categories, whereas the second category is slightly predominant with 38 %. in gus 4, 9, and 12, landslides close to the drainage network are also present, but in much smaller quantities. in gu 4, only the first two categories are present with the predomination of category ii at 71 %. a similar situation occurs with gu 9, the only difference being that the biggest area is category i with 93 %. in gu 12, 77 % is in category i. in gu 8 all categories are present with a predomination of category ii at 49 %. 4.5. microscopic analysis from the microscopic analysis, two analysed samples defined as sandstones, six samples belong to the group of metasandstones, and metasiltstones and six are altered basalts. the other three samples are determined as diabase/dolerite, serpentinised peridotite, and radiolarian chert (table 2). metasediments of the upper palaeozoic complex (c, d), gu 12, are mainly composed of metasiltstone, and metasandstones with limestone interlayers. these rocks most probably are the product of hydrothermal alterations up to very low metamorphic grade. alteration of the majority of the feldspars by processes of sericitisation and chloritization, is one of the major characteristics of these rocks. from these groups, 7 samples were analysed: mvim 15, mvim 16, mvim 17, mvim 18, mvim 32, mvim 33, and mvm 34 (table 2). the main constituents of the mineral composition of the metasediments are quartz, plagioclase (often altered by sericite), white micas, and secondary chlorite, which is a product of the alteration. lithoclasts and chert particles occur in smaller quantities. the diabase/dolerite and altered basalts of the middle jurassic (ββ) (gu 6 and gu 8) are represented by analysed samples with glomeroporphyritic texture and porphyritic texture and amygdaloidal structure (mvim 21, mvim 23, and mvim 24). figure 15. stream network drainage density from low to high (i-iv) different gu’s with landslides in square km (a) and percentages (b). legend in table 1. table 2. the micropetrographic features of the studied rocks: rock type, main mineral phases, and minerals formed by alterations. the last column gives their correspondence to gu’s. samples rock type main minerals main alteration processes products of alterations gu mvim 7 mvim 12 sandstone q, white mica, feldspar sericitisation, weathering clay minerals, iron oxides 7, 5 mvim 15 mvim 16 mvim 17 mvim 18 mvim 33 mvim 34 metasandstone, metasiltstone, q, white mica, ± plagioclase, sericitization, chloritization, white mica, chlorite, 12 mvim 2 mvim 3 mvim 5 mvim 21 mvim 23 mvim 26 altered basalt clinopyroxene, plagioclase, albitization, uralitization, chloritization, calcitization albite, amphibole, chlorite, calcite 6, 8 mvim 24 dolerite/diabase clinopyroxene, plagioclase chloritization, calcitization chlorite, calcite 6, 8 mvim 11 peridotite olivine, pyroxene serpentinization serpentine, magnetite,magnesite 6, 8 mvim 32 radiolarian chert quartz recrystallization quartz modifications 12 g eologia c roatica 29filipović et al.: a case study in the research polygon in glina and dvor municipality, croatia-landslide susceptibility assessment of geological units samples contain relicts of pyroxene affected by chloritization and uralitisation, resulting in secondary minerals of chlorite and actinolite. plagioclase grains are albite, often affected by sericitisation and calcitization. samples mvim 2, mvim 3, mvim 5, and mvim 26 have aphyric/vitrophiric and intersertal texture, where chlorite is a product of the devitrification of volcanic glass. the sample mvim 11 is serpentinised peridotite. olivine and orthopyroxene, under the influence of water, were turned into fibrous-leaf aggregates of serpentine (chrysotile/antigorite), located in olivine grain cracks. in addition to these minerals, talc, carbonates, and chlorite appear secondary. iron from olivine most probably accumulates into a fine-grained aggregate of magnetite, and a part of the magnesium is bound into magnesite. siltstones, sandstones, and cherts of the middle-upper jurassic (gu 7), were represented with a sandstone sample (mvim 12). the mineral composition of the sample is dominated by polygonal quartz grains, plagioclase, and white mica. the sample shows initial phase of chloritization and sericitisation processes rarely. sandstones, siltstone, and cherts from the upper cretaceous series (k2) gu 5 are represented by diverse clastic rocks, marls, limestones, and cherts. the collected sample of sandstone (mvim 7) is composed of polygonal quartz grains and numerous plagioclases and lithoclasts, mainly composed of quartz aggregates. the sample does not show foliation and acts as a slightly altered/weathered sandstone, with sparse opaque minerals probably resulting from limonitization processes. 5. discussion the lithology of an area is a major factor in the formation of landslides in that area (regmi et al., 2012). thus, this study aimed to determine the influence of lithology, drainage, and relief on the distribution of landslides. from a lithological point of view the presented area shows a distinction between several gu’s even though the geometric characteristics of the landslides are very similar. moreover, some gu’s are more prone to landslide processes than others (figure 8). the performed analysis made it possible to group the area into four engineering geological units (egu) as follows: 1) sandstones; 2) metamorphic and igneous rocks; 3) dolomites and metasandstones, and 4) sand and gravel (figure 16). furthermore, these units should represent the basis for further analyses (e.g. landslide susceptibility map). landslide geometric analysis gave insight into the main landslide features. firstly, the area was chosen because metamorphic and igneous rocks are present. the main objective was to determine the susceptibility to landslides of these units. moreover, several units in which sandstone prevails were also covered with lidar scan and analysed herein. at first, it seemed that the figure 16. egu on the studied area. g eo lo gi a c ro at ic a 30 geologia croatica 75/1 whole area behaves as one geological unit (figure 7) as the landslide geometric characteristics are very similar. over the whole area, average landslides are in the moderate category according to šestanović (2001) (figure 6). also, from the length/width ratio it is evident that longitudinal and elongated landslides prevail (tian et al., 2017). terrain prospection also gave insight into the thickness of landslide material. typical landslides are shallow to very shallow, not exceeding 1.5 metres. to understand which class in lithology has more influence on landslide formation, a landslide inventory map has to be combined with the lithological map of the study area (regmi et al., 2012). the relationship between the gu’s and landslide occurrence can be described with the li. li (figure 8) shows a clear distinction between gu’s. relief analysis confirmed that the terrain, in general, is characterised by heterogeneity due to the lithological and geomorphological characteristics of the investigated area (conforti & ietto, 2020). this was partly expected due to the geological characteristics of the mapped units of the area. the similarity of these units exists because older (jurassic) geology, with slightly weathered rocks prevails. hence, the rock mass is very near the surface and not many landslides, with low lr, are recorded (figure 9). most commonly, the landslide age is relative, and landslides can be defined as recent, old, or very old (mccalpin, 1984; antonini et al., 1993). here, high lr points to more recent, younger landslides appearing fresh on the lidar hrdem derivates. furthermore, within older landslides, usually with lower lr, more of their morphology is reshaped and the landslide features are less recognisable (mccalpin, 1984; keaton & degraff, 1996; bell et al., 2012; petschko et al., 2014). moreover, from figure 11 it can be seen that where more surface of a certain gu is present, more or less, all relief categories exist. also, it can be noticed that in gu’s where sandstone prevails, more surface has lower relief values whereas, in the area with metamorphic and igneous rocks, higher relief is prevalent. it is observed that in older gu’s with igneous and metamorphic rocks there are somewhat fewer processes (e.g. erosion, landslides, etc.). drainage networks have a negative impact on landslide susceptibility due to undercutting slope toe and saturating slope material, thereby reducing the stability of the slope (demir et al., 2013). the statistical analyses of drainage show a differentiation between several geological units. firstly, the link between landslides and drainage network within some geological units can be explained due to the lithological composition. lithology and rock structure play a vital role in the development of the drainage network in any drainage basin. the drainage patterns upon land surface develop as directed by the underlying lithology and rock structure (mukherjee & jha, 2011). in figures 14 and 15 it is evident that in gu 3 and in gu’s where sandstones prevail, the drainage network is much more dense. drainage networks can be quantitatively described using parameters such as drainage density, which is the ratio of the total length of streams within a network to the surface area of the network. secondly, drainage network categories are equally distributed in areas where more area of the gu was scanned with lidar and analysed here. furthermore, in all other geological units, particularly the igneous and metamorphic ones it can be concluded that landslides are not dependent on the vicinity of and drainage network development. from these results, several conclusions can be drawn. given the heterogeneity of the presented gu’s, it can be observed that some of them are more susceptible to landslides than others. therefore, an engineering geological categorisation of the area into four zones with similar degrees of landslide susceptibility was made. in the first egu category (gu 3, 4, 5 and 7), where sandstones predominate, a slightly thicker regolith was recorded (> 1m) during field research. regolith is a mixture of mud, sand, and gravel. in these units, the li (figure 8) ranges from 5 % to a maximum of 10 %. in the second egu category (gu 6 and 8), where metamorphic and igneous rocks are observed, regolith values range from 0.5-1.0 m and it is also a mixture of sand and gravel with a very small amount of mud component. for this category the li index is around 1.5 %. regolith in the third category (gu 9, 10, and 12) has a thickness of less than 0.5 m and is a mixture of sand and gravel. the li index shows values lower than 0.5 %. only with gu 9, with a predominant dolomite lithology, the li is around 4 %. this unit is classified as egu 3 for several reasons. firstly, during field prospection and cabinet analysis, it is observed that the boundaries between the geological units are not always precise, this is also attributed to the scale of the map used as a basis for these analyses (hećimović & avanić, 2014). given that the landslides are present on the border of the previously mentioned dolomites and sandstones from gu 5, it is evident that the landslide started in gu 5, located hypsometrically above unit gu 9 (see the yellow polygon in figure 1 with symbol a). landslides are formed in a slightly thicker sandstone regolith, which subsequently slides on a solid impermeable dolomite surface. as for gu 12, it is categorised as egu 3, even though sandstones and shale prevail which are placed in egu 1. the decision was made because the unit is not so susceptible to landslides, as its landslide index is around 1 %. in the unit, landslides only appear near major important springs on the geological boundary with the sandstones of gu’s 7 and 12 (see the green polygon in figure 1 with symbol b). also, the reason why the unit is not susceptible to landslide can be found in the composition of these sandstones. microscopic analyses indicate that these sandstones are siliciclastic, and therefore during the formation of the regolith quartz, feldspars and mica are more abundant, whereas in other sandstones with slightly greater susceptibility to sliding, units may also contain clay minerals in the regolith. the fourth egu group involves a mixture of sand, gravel, silt and clay from the holocene (gu 1). in the aforementioned unit, there are no landslides, this is expected as the terrain is almost flat. it is important to emphasise that a mixture of gravel, sand, and clay from quaternary deposits are not grouped into any egu because a very small area is covered with lidar. even though in the literature (jurak et al, 1998) it is emphasised that the greatest number of landslides can be found in the area of miocene (m7 1-2) and plioquaternary deposits (pl,q), if more surface would be covered, the unit would be classified as egu 1. lithology is one of those parameters known to influence landslides in some regions because certain geological conditions accelerate weathering and prepare the rock for mass movements (goretti, 2010). fresh rocks contain a large amount of quartz, with some calcite, sericite, and some feldspar, while the weathered rocks are rich in clay minerals and a few opaque minerals (regmi et al., 2012). for this reason, microscopic analyses gave insight into the mineral composition of the gu’s. gu 3 has not been investigated microscopically in more detail in this study as there are valid data available in the literature. investigation of these sediments was done by tibljaš & šćavničar (1985), tibljaš (1987), tibljaš et al. (2017a, b), tibljaš (2019) and radić (2019). they reported zeolites, stibnite and laumontite, in the form of cement and in veinlets. the authors, using x-ray g eologia c roatica 31filipović et al.: a case study in the research polygon in glina and dvor municipality, croatia-landslide susceptibility assessment of geological units diffraction on polycrystalline samples, additionally determined the kübler (ki) and árkaiev (ai) index as indicators of thermal changes and reported that clay minerals in the vicinity of hrvatska kostajnica are represented by smectites or vermiculites (swelling clay), corrensite and chlorite. these sediments correspond to our gu 3 deposits. at the same time, the presence of illite and chlorite-smectite interstratifications and minor swelling clay reported in the references of the same authors are linked to gu 5. swelling clays are emphasised in gu 4 deposits. gu 5 clastic and metasedimentary rocks are difficult to distinguish from gu 3 units due to the absence of fossils and unclear geological relationships. it could be concluded that landslide occurrence and higher li values in these deposits with prevalent siliciclastic sediments (gu 3, 4, and 5) can be explained by the presence of clay minerals. clay minerals can take up large amounts of water in their interlayers, which raises pore pressure, consequently lowering the effective strength of the material. in the middle to upper jurassic igneous rocks (gu 6 and 8) instabilities and sliding were not reported, therefore lower li values were to be expected and sliding, therefore lower li values were to be expected. in contrast, in the middle-upper jurassic metamorphic rocks (gu 7) with prevalent sandstones, shallow landslides are formed. alteration products contain clay minerals and iron oxides which can explain the higher number of landslides in this unit than units gu 6 and gu 8. minerals found in these sandstones include quartz, white mica, feldspar which explains the lower li values in gu 7 than the gu 3 sandstones where clay minerals are present. the overall conclusion is that the area, in general, is characterised by very similar types of landslides. in all the lithological units, landslides are quite shallow, up to 1.5 metres, with bedrock material often very close to the surface. moreover, landslides in these units are moderate to large, and sometimes even exceed a dozen square kilometres. usually not all of the main landslide characteristics are visible and because of this, we suppose that most of the landslides in a studied polygon can be classified as old landslides (mccalpin, 1984; antonini et al., 1993). moreover, a very small number of landslides are highly ranked just for this reason (figure 9). still, several high graded landslides are registered near important springs in gu12, which typically is not prone to landslides, as stated above. bearing in mind that the gu 12 on the boundary with the gu 3 with a predominant sandstone lithology, it can be assumed that the water infiltrates into the thicker sandstone regolith, and springs appear when it reaches the impermeable gu 12 metasandstone lithology (marked green polygon in figure 1 with symbol b). moreover, weather extremes very often affect the hydrological conditions, which can raise the pore water pressure and decrease the effective stress, which can consequently trigger landslides. nevertheless, the extent of these phenomena also depends on the amount of precipitation, lithological composition, and terrain relief. however, morphological relief analysis showed that landslides are present on the borders of a steep and low relief where erosion processes are still active. relief analysis also shows some differences between the analysed processes in gu’s. a small number of landslides in gu 12 can be explained by the presence of the mineral quartz, which is physically and chemically resistant to weathering, white mica and plagioclase. 6. conclusion this study represents the first analyses of the lidar hrdem derivates in identifying and mapping landslides in a 48.45 km2 polygon in sisak moslavina county. a total of 477 landslides are mapped with a landslide density of 9.85 landslides per square km. landslide sizes range from 89 m2 to 104440 m2 with average sizes of 4835 m2 and a median of 2430 m2 which can be characterised as moderate landslides. further analyses of the specific geometric properties of these landslides can be used as a starting point in understanding the underlying structural processes controlling the movement of the landslides. the li was calculated to quantitatively define the strength of the relationship between the occurrence of landslides in different geological units. consequently, li was used as one of the main factors to quantitatively assess the landslide susceptibility of each gu. with the help of li, it was possible to group the gus into four egu of rocks with similar properties. the first group of rocks, with the highest li values, belongs to the eocene-oligocene (gu 3); palaeocene (gu 4), lower-upper cretaceous (gu 5), and middle-upper jurassic (gu 7) where sandstone lithology prevails. moreover, the lower triassic (gu 11) is also classified as egu 1 even though the li is very small. therefore, grouping was made considering the prevailing sandstone lithology in the unit and that only an area of 1.35 km2 is covered with lidar scanning. the second egu group involves middle-upper jurassic metamorphic and igneous rocks, of ββ (gu 6) and j2,3(gu 8). the third egu groups involve upper and middle triassic dolomites (gu 9 and gu 10) and carboniferous and devonian (gu 12) metasandstones. the fourth egu group involves a mixture of sand, gravel, silt, and clay from the holocene (gu 1). it is important to emphasise that a mixture of gravel, sand, and clay from quaternary deposits are not grouped into egu because a very small area covered with lidar. relief and drainage network parameters in regard to landslide occurrence were also analysed. the purpose of this analysis was to additionally confirm the division of egu units based on geometric parameters and li index. firstly, analysis of relief showed that in gu’s where sandstone prevails more surface has lower relief values whereas where metamorphic and igneous rocks are predominant higher relief is prevalent. moreover, drainage network analysis indicate that in formations where sandstone lithology prevails, the drainage network is more dense and consequently causes weakening of slope stability, which is often the cause of landslides. microscopic analyses gave insight into the mineral composition of the gu’s. landslide occurrence in deposits with general sandstone lithology and higher li values can be explained by the presence of clay minerals that can take up large amounts of water in their interlayers, which raises pore pressure, consequently lowering the effective strength of the material leading to landslide. lower li values and shallow landslides in the middle-upper jurassic igneous rocks could be explained by the presence of more resistant minerals. middle-upper jurassic metamorphic rocks with prevalent sandstones are associated with a slightly thicker regolith mainly composed of silt, sand, and gravel forming shallow landslides. this could be explained by the products of alteration which can result in the formation of clay minerals. very low li values can be attributed to more resistant minerals such as quartz. the lidar hrdem was advantageous for identifying and mapping landslides in this inaccessible and forested area for which a historical landslide inventory was made. results of landslide spatial distribution in comparison to lithology, relief and drainage serve as a basis for the determination of landslide susceptibility of this area. given the different scales of the maps used g eo lo gi a c ro at ic a 32 geologia croatica 75/1 during the interpretation of the data it would be advantageous to include more detailed, larger scale, geological maps during the interpretation of lidar data in the future. furthermore, lidar data enables the production of statistically based landslide susceptibility maps. this research is also a basis for further work on landslide susceptibility in areas with similar geological conditions and it offers a basis for a more detailed geomorphological analysis with regard to landslide susceptibility. acknowledgment this study was carried out within the safearth interreg ipa croatia-bosnia and herzegovina and montenegro 2014-2020 project – transnational advanced management of land use risk through landslide susceptibility maps design. the authors are thankful for the provision of lidar hrdem data obtained during this project. the analysis of the six samples from the mvim-21 sampling point was studied through the bachelor thesis of matteo blatančić. (university of zagreb faculty of mining, geology and petroleum engineering). additionally, the authors appreciate koraljka bakrač (head of department of geology, croatian geological survey) for permission to use the geological map of sisak-moslavina county 1:100.000 (hećimović & avanić, 2014) for the purpose of this scientific publication. references ahmed, m.f., rogers, j.d. & ismail, e.h. (2014): a regional level preliminary landslide susceptibility study of the upper indus river basin.– european journal of remote sensing, 47/1, 343–373. doi: 10.5721/eujrs20144721 allaby, a. & allaby, m. (2003): dictionary of earth sciences.– oxford university press, uk. 619 p. antonini, g., cardinali, m., guzzetti, f., reichenbach, p. & sorrentino, a. (1993): carta inventario dei fenomeni franosi della regione marche ed aree limitrofe.– cnr, gruppo nazionale per la difesa dalle catastrofi idrogeologiche, publication n. 580, 2 sheets, scale 1:100.000 (in italian). basch, o. (2009): paludinske naslage (dacij, romanij – pl) [paludine beds – pl – in croatian] – in: velić, i. & vlahović, i. (eds.): explanatory note for the geological map of the republic of croatia 1:300.000. croatian geological survey, department of geology, zagreb, 90-91. bathrellos, g.d., kalivas, d.p.& skilodimou, h.d. (2009): gis-based landslide susceptibility mapping models applied to natural and urban planning in trikala, central greece.– estudios geológicos, 65/1, 49–65. doi:10.3989/egeol.08642.036 bell, r., petschko, h., röhrs, m. & dix, a. (2012): assessment of landslide age, landslide persistence and human impact using airborne laser scanning digital terrain models.– geografiska annaler: series a, physical geography, 94, 135–156. doi: 10.1111/j.1468‐0459.2012.00454.x bognar, a. (2001): geomorfološka regionalizacija hrvatske [geomorphological sregionalisation of croatia – in croatian].– acta geographica croatica, 34, 7–29. brabb, e.e., grazmer, r.w. & jones, d.l. (2000): geologic map and map database of the palo alto 30’ x 60’ quadrangle, california.– u.s. geological survey miscellaneous field studies map mf-2332. u.s., menlo park, ca. conforti, m. & ietto, f. (2020): influence of tectonics and morphometric features on the landslide distribution: a case study from the mesima basin (calabria, south italy).– journal of earth science, 31, 393–409. doi: 10.1007/s12583-0191231-z cruden, d.m. & varnes, d.j. (1996): landslide types and processes.– in: turner, a.k. & schuster, r.l. (eds.): landslides, investigation and mitigation. transportation research board. special report 247, washington d.c., usa, 36–75. čubrilović, p., palavestrić, lj., nikolić, t.& ćirić, b. (1967): inženjerskogeološka karta sfr jugoslavije 1:500000 [basic engineering geological map of sfry 1:500.000 – in croatian].– savezni geološki zavod, beograd. demek, j. (1972): manual of detailed geomorphological mapping.– commission on geomorphological survey and mapping, 334 p. demir, g., aytekin, m., akgün, a.,ikizler, s.b.& tatar, o. (2013): a comparison of landslide susceptibility mapping of the eastern part of the north anatolian fault zone (turkey) by likelihood–frequency ratio and analytic processes methods.– natural hazards, 65, 1481–1506. doi: 10.1007/s11069-012-0418-8 fell, r., corominas, j.& bonnard, c. (2008): guidelines for landslide susceptibility, hazard and risk zoning for land use planning.– engineering geology, 102, 85–98. doi: 10.1016/j.enggeo.2008.03.022 ghosh, s., van westen, c.j.&carranza, e.j.m. (2012): generating eventbased landslidemaps in a data-scarce himalayan environment for estimating temporal and magnitude probabilities.– engineering geology, 128, 49–62. doi: 10.1016/j.enggeo.2011.03.016 gerić, a.(2019): geomorfološki značaj klizišta sjevernog dijelakarlovačke županije [geomorphological significanceof landslides in northern part of karlovac county – in croatian].– unpubl. master thesis, faculty of science, department of geography, univerity of zagreb, 59 p. goretti, k.k.m. (2010): landslide occurrence in the hilly areas of bududa districts in eastern uganda and their causes.– unpubl. phd thesis, makerere university, department of geology, uganda, 106 p. guzzetti, f., carrara, a., cardinal, m. & reichenbach, p. (1999): landslide hazard evaluation: a review of current techniques and their application in a multi-scale study, central italy.– geomorphology, 31, 181-216. doi: 10.1016/ s0169-555x(99)00078-1 guzzetti, f., mondini, a.c., cardinali, m., fiorucci, f., santangelo, m. & chang, k.t. (2012): landslide inventory maps: new tools for an old problem.– earth-science reviews, 112, 42–66. doi: 10.1016/j.earscirev.2012.02.001 hećimović, i. (2009): klastične naslage (pliokkvartar – pl, q) [clastic deposits (plioquaternary – pl, q – in croatian].– in: velić, i. & vlahović, i. (eds.): explanatory note for the geological map of the republic of croatia 1:300.000. croatian geological survey, department of geology, zagreb, 94–95. hećimović, i.& avanić, r. (2014): studija potencijala i osnove gospodarenja mineralnim sirovinama sisačko-moslavačke županije [study of potenical and basics of minerals resources management in sisak-moslavina county – in croatian].– unpubl. report, hrvatski geološki institut, zagreb, 489 p. horton, r.e. (1945): erosional development of streams and their drainage basins: hydrophysical approach to quantitative morphology.– bulletin of the geological society of america, 56, 275–370. doi: 10.1177/030913339501900406 hutchinson, j.n. (1995): landslide hazard assessment.– in: proceedings vi, international symposium on landslides, christchurch, 1, 1805–1842. jaboyedoff, m., oppikofer, t. & abellan, a., (2010): use of lidar in landslide investigations: a review.– natural hazards, 61, 5–28. doi: doi.org/10.1007/ s11069-010-9634-2 jagodnik, p., jagodnik, v., arbanas, ž. & mihalić arbanas, m. (2020): landslide types in the slani potok gully, croatia.– geologia croatica, 73/1, 13–28. doi: 10.4154/gc.2020.04 jurak, v., matković, i., miklin, ž. & cvijanović, d. (1998): landslide hazard in the medvednica submountain area under dynamic conditions.– in: marić, b., lisac, z. & szavits-nossan, a. (eds.): geotechnical hazards, xith danube-european conference on soil mechanics and geotechnical engineering, poreč, croatia. keaton, j.r. & degraff, j.v. (1996): surface observation and geologic mapping.– in: turner, a.k. & schuster, r.l. (eds.): landslides – investigation and mitigation, national research council, washington, dc, 178–230. köppen, w.& wegener, a. (1924): the climates of the geological past.– facsimile of the german original and english translation of die klimate der geologischen vorzeit, berlin, stuttgart. kumar, v., gupta, v. & sundryal, y.p. (2018): spatial interrelationship of landslides, litho‐tectonics, and climate regime, satluj valley, northwest himalaya.– geological journal, 54, 537–551. doi:10.1002/gj.3204 lee, s.& talib, j.a. (2005): probabilistic landslide susceptibility and factor effect analysis.– environmental geology, 47, 982–990. doi: 10.1007/s00254-005-1228-z lozić, s. (1995). vertikalna raščlanjenost reljefa kopnenog dijela republike hrvatske[vertical relied dissection analysis of the land part of the reepublic of croatia – in croatian].– acta geographica croatica, 30/1, 17–26. marković, m. (1983): osnovi primjenjene geomorfologije[basis of geomorphology– in serbian].– geoinstitut, oour istraživanje mineralnih sirovina, inženjerska i hidrogeologija, beograd, 174 p. mccalpin, j. (1984): preliminary age classification of landslides for inventory mapping.– proceedings of the 21st engineering geology and soils engineering symposium.ng 2005. moradi, s. & rezaei, m. (2014): a gis-based comparative study of the analytic hierarchy process, bivariate statistics and frequency ratio methods for landslide susceptibility mapping in part of the tehran metropolis, iran.– geopersia, 4, 45–61. doi:10.22059/jgeope.2014.51191 mukherjee, s. & jha, v.,c. (2011): role of lithology and rock structure in drainage development in the kaliani river basin, assam, india.– ethiopian journal of environmental studies and management. 4, 2. doi: 10.4314/ejesm.v4i2.7 nenadić, ž., lovrić, m., šimović, v.& salopek, d. (2010): zrinska gora.– grad petrinja, sisačko-moslavačka županija, sveučilište u zagrebu, učiteljski fakultet – odsjek petrinja, matica – hrvatska – ogranak petrinja, 174 p. ng, k.y. (2006): landslide locations and drainage network development:a case study of hong kong.– geomorphology, 76, 229–239. doi:10.1016/j.geomorph.2005.10.008 g eologia c roatica 33filipović et al.: a case study in the research polygon in glina and dvor municipality, croatia-landslide susceptibility assessment of geological units niyazov, r. & nurtaev, b. (2017): the role of simultaneous impact of exogenousand endogenous forces in landslide processactivation.– in: mikos et al. (eds.): advancing culture of living with landslides. 4th world landslide forum ljubljana, slovenia. springer international publishing ag 2017m. doi:10.1007/9783-319-53485-5_2. pamić, j., gušić, i. & jelaska, v. (1998): geodynamic evolution of the central dinarides.– tectonophysics, 297, 4; 251–268. doi: 10.1016/s0040-1951(98)00171-1 papathanassiou, g., valkaniotis, s. & ganas, a. (2020): spatial patterns, controlling factors, and characteristics of landslides triggered by strike-slip faulting earthquakes: case study of lefkadaisland, greece.– bulletin of engineering geology and the environment, 80, 3747–3765. doi: 0.1007/s10064-021-02181-x petschko, h. bell, r. & glade, t. (2014): relative age estimation at landslide mapping on lidar derivatives: revealing the applicability of land cover data in statistical susceptibility modelling.– in: sassa, k., canuti, p. & yin, y. (eds.): landslide science for a safer geoenvironment, springer, 337–343. doi: 10.1007/978-3-319-05050-8_53 peshevski, i., jovanovski, m., abolmasov, b., papić, j., đurić, u., majranović, m., haque, u. & nedelkovska, n. (2019): preliminary regional landslide susceptibility assessment using limited data.– geologia croatica, 72/1, 81–92. doi: 10.4154/gc.2019.03 pintarić, l. (2020): šumski stanišni tipovi zrinske gore prema nacionalnoj klasifikaciji staništa i europskimklasifikacijama [forests of zrinska gora mt. according to national habitat classification and european classifications – in croatian].– unpubl. graduate thesis,faculty of forestry, university of zagreb, 53 p. radić, s. (2019): clay minerals in eocene rocks from hrvatska kostajnica surroundings.– unpubl. seminar iii, university of zagreb, faculty of science, 32 p. regmi, d.a., yoshida, k., nagata, h., pradhan, s.m.a., pradhan, b.& pourghasemi, r.h. (2012): the relationship between geology and rock weathering on the rock instability along mugling–narayanghat road corridor, central nepal himalaya.– natural hazards, 66, 501–532. doi: 10.1007/s11069-012-0497-6 schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine-carpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss journal of geosciences, 101/1, 139–183. doi:10.1007/s00015-008-1247-3 soeters, r. & van westen, c.j. (1996): slope instability recognition, analysis, and zonation.– in: turner, a.k. & schuster, r.l. (eds.): landslides, investigation and mitigation. transportation research board, special report 247, washington d.c., usa, 129–177. sokač, b. (2009a): sajske i kampilske naslage (donji trijas – t1) [siusi and campil beds – (lower triassic – t1) – in croatian].– in: velić, i. & vlahović, i. (eds.): explanatory note for the geological map of the republic of croatia 1:300.000. croatian geological survey, department of geology, zagreb, 29–32. sokač, b. (2009b): karbonatne naslage (srednji trijas – t2) [carbonate deposits (middle triassic – t2) – in croatian].– in: velić, i. & vlahović, i. (eds.): explanatory note for the geological map of the republic of croatia 1:300.000. croatian geological survey, department of geology, zagreb, 32–34. šapić, i. (2012): šumska vegetacija zrinske gore [forest vegetation of zrinska gora – in croatian].– unpubl. ph.d. thesis, faculty of forestry, university of zagreb, 216 p. šestanović, s. (2001): osnove geologije i petrografije [fundamentals of geology and petrography – in croatian].– sveučilište u splitu, građevinski fakultet, 234 p. šikić, k. (2009a): klastične i karbonatne naslage (devon, karbon – d, c)[clastic and carbonate deposits – (devonian, carboniferous – d,c) – in croatian].– in: velić, i. & vlahović, i. (eds.): explanatory note for the geological map of the republic of croatia 1:300.000. croatian geological survey, department of geology, zagreb, 18–19. šikić, k. (2009b): ofiolitno-sedimentni kompleks [ophiolite-sedimentary complex – in croatian].– in: velić, i. & vlahović, i. (eds.): explanatory note for the geological map of the republic of croatia 1:300 000. croatian geological survey, department of geology, zagreb, 54–54. šikić, k. (2009c): metamorfne stijene (srednja–gornja jura – j2,3) [metamorphic rocks (middle–upper jurassic –j2,3 – in croatian].– in: velić, i. & vlahović, i. (eds.): explanatory note for the geological map of the republic of croatia 1:300.000. croatian geological survey, department of geology, zagreb, 54–55. šikić, k. & bergant, s. (2009): hemipelagičke i turbiditne naslage (donja kreda – k1)[hemipelagic and turbidite beds (lower cretaceous – k1 – in croatian)].– in: velić, i. & vlahović, i. (eds.): explanatory note for the geological map of the republic of croatia 1:300.000. croatian geological survey, department of geology, zagreb, 69–70. šikić, k., halamić, j. & belak, m. (2009): ofiolitne stijene (srednja-gornja jura – j2,3) [ophiolite rocks (middle–upper jurassic) – j2,3 – in croatian].– in: velić, i. & vlahović, i. (eds.): explanatory note for the geological map of the republic of croatia 1:300.000. croatian geological survey, department of geology, zagreb, 57–60. šimunić, an. (2009): karbonatni fliš i klastiti (paleocen, eocen – pc, e) [carbonate flysch and clastic beds (paleocene, eocene – pc, e)– in croatian].– in: velić, i. & vlahović, i. (eds.): explanatory note for the geological map of the republic of croatia 1:300.000. croatian geological survey, department of geology, zagreb, 75–76. šparica, m., bukovac, j. & bergant, s. (2009): karbonatni klastiti (pretežito fliš) i ‘scaglia’ vapnenci (gornja kreda – k2) [carbonate clastic beds (mostly flysch) and ‘scaglia’ limestones (upper cretaceous – k2) – in croatian].– in: velić, i. & vlahović, i. (eds.): explanatory note for the geological map of the republic of croatia 1:300.000. croatian geological survey, department of geology, zagreb, 70–72. tian, y., xu, c., chen, j., zhou, q. & shen, l. (2017): geometrical characteristics of earthquake-induced landslides and correlations with control factors: a case study of the 2013 minxian, gansu, china, mw 5.9 event.– landslides, 14, 1915–1927. doi: 10.1007/s10346-017-0835-6 tibljaš, d. & šćavničar, s. (1985): zeoliti u eocenskom konglomeratu kod velešnje (zapadno od kostajnice) [zeolites in eocene conglomerates from velešnja (west of kostajnica) – in croatian].– mineralogija, 1, godišnjak jam, 207–215. tibljaš, d. (1987): mineraloška istraživanja zeolita iz kenozojskih sedimenata kod velešnje na baniji i donjeg jesenja u hrvatskom zagorju [mineralogical investigation of zeolites from cenozoic sediments near velešnja in banija and donje jesenje in hrvatsko zagorje – in croatian].– unpubl. msc. theses, university of zagreb, faculty of science, 87 p. tibljaš, d., topalović, e. & balen, d. (2017a): clay minerals as thermal history indicators of inner dinarides lithologies from the surroundings of hrvatska kostajnica (croatia).– in: xvi international clay conference, icc 2017, granada, spain. scientific research abstracts, vol. 7, digilabs pub., bari, p. 756. topalović, e. (2017b): minerali glina kao indikatori termalnih promjena u stijenama okolice hrvatske kostajnice [clay minerals as indicators of thermal alteration in the rocks in the vicinity of hrvatska kostajnica – in croatian, with english abstract].– unpubl gradutate thesis. faculty of science, university of zagreb. v+69 p. thornthwaithe, c.w. (1931): the climates of north america: according to a new classification.– geographical review, 21, 633–655. doi: 10.2307/209372 tibljaš, d. (2019): termalna povijest terena u kredi (kristalinitet illita) [thermal history of cretaceous deposits (illite crystallinity) – in croatian].– cretaceous geodynamic proofs in the dinarides and pannonian basin, project public presentation of results and project outcomes, theme 07, 17 p. van den eeckhaut, m., poesen, j., verstraeten, g., vanacker, v., nyssen, j., moeyersons, j., van beek, l.p.h. & vandekerckhove, l. (2007): use of lidar-derived images for mapping old landslides under forest.– earth surface processes and landforms, 32, 754–769. doi: 10.1002/esp.1417 van den eeckhaut, m., hervás, j., jaedicke, c., malet, j.p., montanarella, l. & nadim, f. (2012): statistical modeling of europe-wide landslidesusceptibility using limited landslide inventory data.– landslides, 9, 357–369. doi: 10.1007/s10346-011-0299-z van westen, c.j., rengers, n., terlien, m.t.j. & soeters, r. (1997): prediction of the occurrence of slope instability phenomena through gis-based hazard zonation.– geologische rundschau, 86: 404–414. doi: 10.1007/s005310050149 van westen, c.j., rengers, n. & soeters, r. (2003): use of geomorphological information in indirect landslide susceptibilitz assesment.– engineering geology, 102, 112–131. doi: 10.1007/s10346-011-0299-z van westen, c.j., castellanos, e. & kuriakose, s.l. (2008): spatial data for landslide susceptibility, hazard, and vulnerability assessment.– natural hazards, 30, 399–419. doi: 10.1023/b:nhaz.0000007097.42735.9e varnes, d.j. (1978): slope movement types and processes.– in: schuster. r.l. & krizek r.j. (eds.): landslides, analysis and control, special report 176. transportation research board, national academy of sciences, washington, dc., 11–33. zhou, s., chen, g., fang, l. & nie, y. (2016): gis-based integration of subjective and objective weighting methods for regional landslides susceptibility mapping.– sustainabilty, 8, 334. doi: 10.3390/su8040334 www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2024 | 77/2 | 159–178 | 18 figs. | article history: manuscript received: april 16, 2024 revised manuscript accepted: may 29, 2024 available online: june 21, 2024 keywords: minjera, istrian palaeogene bauxites, pyritisation in karst bauxites, iron sulphide morphology in karst bauxites, stable sulphur isotopes in karst bauxites 1. introduction the minjera bauxites are a unique and historically important group of karst bauxite deposits from istria, croatia, as they represent the first locality where bauxite was mined in the world, even though, at that time, it was not known that this material would be named bauxite in the future. the mining activity dates back as far as the 16th century, but was historically recorded only from 1784 until 1824, when the majority of mining activity occurred (d’ambrosi, 1926). the bauxite ore was used in the production of alum and vitriol, which were obtained after the ore was processed in the production plant. the ore was particularly suitable for the production of these materials as it has a high pyrite content, a very specific feature of these deposits compared to other palaeogene bauxites in istria. all this has made these deposits appealing for geological investigations and field excursions, with the first and most complete study being that by tracing the evolution of the world's first mined bauxite from palaeotopography to pyritization: insights from minjera deposits, istria, croatia ivor perković1,*, maja martinuš2, blanka cvetko tešović2, igor vlahović1, darko matešić1, robert j. newton3, tianchen he3,4, marin šoufek5, ivan razum5 and goran durn1 1 university of zagreb, faculty of mining, geology and petroleum engineering, 10000 zagreb, croatia; (* corresponding author: ivor.perkovic@rgn.unizg.hr) 2 university of zagreb, faculty of sciences, department of geology, 10000 zagreb, croatia 3 university of leeds, school of earth and environment, ls2 9jt leeds, united kingdom 4 hohai university, college of oceanography, 210024 nanjing, china 5 croatian natural history museum, 10000, zagreb, croatia doi: 10.4154/gc.2024.12 abstract the minjera bauxites are the first analysed and mined bauxites in the world. they are a group of pyritised bauxites situated in northern istria, developed during the subaerial exposure phase which marked a major part of the late cretaceous and palaeocene in northern istria. in this study, the morphology, petrography, mineralogy, geochemistry as well as stable sulphur isotopes of the d-1 and d-15 deposits from minjera were studied, as well as the evolution of their bedrock and cover. this study found that those two deposits differ in morphology, mineralogy and geochemistry as a consequence of their different palaeotopographical positions, with the d-1 deposit located at a higher position at the time of its formation compared to d-15, which led to the higher degree of leaching and desilicification in the d-1 deposit. the pyritisation in the studied deposits was a multi-phase process, which began with the deposition of framboidal pyrite and micrometre-sized anhedral pyrite, over which colloform pyrite was precipitated. this indicates that the solutions were initially supersaturated with iron sulphide, saturation of which subsequently changed, as finally euhedral, dendritic and acicular pyrite were deposited, indicating undersaturated conditions. the final stage was marked by deposition of pyrite veins. this formational sequence of pyrites is also supported by stable sulphur isotopes, as the δ34s values exhibit a wide range from -40.86 to 2.32 ‰, where lower values indicate an open system with an unrestricted sulphate supply in which supersaturated conditions could have been achieved, while the higher values indicate a change towards a closed system with limited sulphate supply. the organic matter necessary for microbial sulphate reduction was derived from the marshy environment established atop of the bauxite. the initial flooding started in the palaeocene, with the first part of the sequence being deposited under lacustrine conditions, which changed towards fully marine with the deposition of foraminiferal limestones. šinkovec et al. (1994), which was followed by brief investigations for field excursions led by durn et al. (2003, 2006, 2023). pyritised bauxites have been documented all over the mediterranean bauxite belt (bardossy, 1982; dragović, 1989; öztürk et al., 2002; laskou & economouelio poulos, 2007, 2013; radusinović & papa dopoulos, 2021, economou-eliopoulos et al., 2022), and elsewhere (zarasvandi et al., 2012; ellahi et al., 2015, 2017; chen et al., 2022; zhao et al., 2023). the pyritisation phase is a consequence of diagenetic changes and is related to the transgression that followed the bauxitisation phase, during which a marshy environment was established on top of the bauxites, promoting the mobilisation of iron and pyrite formation. pyrite morphology is a useful tool in the palaeoenvironmental and redox reconstructions in sedimentary settings and in the formation of ore deposits (chen, 1978; g eo lo gi a c ro at ic a 160 geologia croatica 77/2 raiswell, 1982; wignall & newton, 1998; barrie et al., 2009; huang et al., 2020; he et al., 2022; mederski et al., 2022; wang et al., 2022). this is also used as one of the foundations for the reconstruction of the genetic evolution of pyritised bauxites (öztürk et al., 2002; laskou & economou-eliopoulos, 2007, 2013; zarasvandi et al., 2012; ellahi et al., 2017; chen et al., 2022; zhao et al., 2023), which is commonly coupled with the use of stable sulphur isotopes allowing the identification of the sulphur source and its evolutionary pathway which led to pyrite formation (öztürk et al., 2002; laskou & economoueliopoulos, 2007; chen et al., 2022; zhao et al., 2023). such an approach was also used here through careful analysis of iron sulphide morphologies and sulphur isotopes, in an attempt to produce improved reconstruction of diagenetic changes that led to the pyritisation of the minjera bauxites. since the flooding of the bauxite and its alteration in a marshy environment is one of the key aspects of those deposits, the kozina beds from the immediate cover of the bauxites were also studied, in order to better understand the palaeoenvironmental changes that followed the subaerial exposure phase. to additionally enhance the reconstruction of the diagenetic changes that the minjera bauxite experienced, as well as the original conditions in which they formed, the trace and rare earth elements (ree) were carefully studied. namely, their behaviour has been extensively used to reconstruct the genesis of different bauxite deposits, since they respond to physico-chemical changes, intensity of chemical weathering as well as changes in ph and redox potential (maksimović et al., 1991; maksimović & pantó, 1991; mongelli, 1997; abedini & calagari, 2014; mongelli et al., 2014, 2017; ellahi et al., 2017; abedini et al., 2018, 2019; yang et al., 2019; tomašić et al., 2021). overall, this study aims to enhance the current knowledge regarding the historically important minjera bauxites and istrian palaeogene bauxites in general, through the construction of an updated genetic model based on different analytical methods, which should also prove useful in the future studies of pyritised bauxites elsewhere. 2. regional geotectonic setting palaeogene bauxites are common throughout northern, eastern and southern istria, and their stratigraphic position fits within the widespread perimediterranean bauxitization event resulting in formation of a vast bauxite belt stretching from hungary through slovenia, croatia, bosnia and herzegovina, montenegro, and albania to greece. this widespread bauxitization event coincided with the late cretaceous closure of the vardar ocean (schmid et al., 2008, 2020; van hinsbergen et al., 2020), which led to the formation of a large foreland basin in the area of today's internal dinarides, causing the tectonic uplift of the adriatic carbonate platform area due to the development of the flexural forebulge in response to the overburden pressure generated by the advancing nappes (otoničar 2006, jež & otoničar, 2018). the emerged areas in the flexural forebulge served as the environment in which the palaeogene bauxites of istria and dalmatia formed. consequently, these bauxites belong to those formed in collisional settings, known as type-1 bauxites according to d’argenio & mindszenty (1995). the duration of subaerial exposure between the cretaceous and palaeogene in istria lasted mostly between 28 my (in southern istria and mt. učka klippe) and 40 my (in northern istria). however, in the western istrian anticline subaerial exposure locally persisted for more than 75 my, as indicated by erosional remnants of eocene foraminiferal limestones which locally transgressively cover different levels of karstified lower cretaceous limestones (the oldest being valanginian in age; matičec et al., 1996). more than 10,000 bauxite occurrences and small bauxite deposits are known in istria (milan mihovilović, pers. comm.), serving as evidence of widespread and intense bauxitization during this period. as deformation continued, rapid subsidence of the foreland area along the partially exposed former adriatic carbonate platform commenced, leading to restoration of marine carbonate production in the form of foraminiferal limestones, followed by deepening, recorded by transitional marls and turbidites (vlahović et al., 2005). 3. geological setting the minjera bauxites are located in the easternmost part of the northern istrian buzet–savudrija anticline (fig. 1), also known as the buje anticline (bergant et al., 2020). bauxites are situated on karstified upper cenomanian limestones belonging to the milna fm. (bergant et al., 2020), with their hanging wall comprising the freshwater to brackish palaeogene kozina beds (šinkovec et al., 1994). during the albian, relatively uniform shallow-marine environments predominated over the entire area of the adriatic carbonate platform. however, in northern istria, significant changes in depositional environments occurred during the early cenomanian (vlahović et al., 1994). in the western part of northern istria, shallow marine sedimentary environments persisted, while in the central part, prograding sand bars composed of finely crushed rudist and chondrodont bioclasts formed. in contrast, the eastern part of northern istria, including the study area, experienced a deepening of sedimentary environments. there, in addition to typical lagoonal limestones, hummocky cross-stratified deposits occasionally occurred in the offshore-transition zone, along with limestones reflecting pelagic influences containing calcisphaeres, silicisponge spicules, algae, and rare planktonic foraminifera (vlahović et al., 1994). towards the end of the cenomanian, a gradual regression occurred throughout northern istria, leading to a regional unconformity in the area, although pelagic influences persisted occasionally in the eastern part. throughout the entire area of the savudrija–buzet anticline, the topmost parts of the upper cenomanian limestones are heavily karstified due to subaerial exposure. in the studied area of the mirna river valley, an irregularly karstified surface is covered with numerous small bauxite bodies and transgressive palaeogene beds. intense karstification occurred especially along fractured zones, resulting in numerous smaller and larger sinkholes and decametre-sized karstic canyons that served as sediment traps for the accumulation of the source material for bauxite formation. the red colour and common oolitic structure of the palaeogene g eologia c roatica 161perković et al.: tracing the evolution of the world's first mined bauxite from palaeotopography to pyritization: insights from minjera deposits ... bauxites in northern istria indicate highly elevated and intensely karstified carbonate bedrock, typical of vadose lithofacies in carbonate terrains uplifted at least several dozen metres above sea level (d’argenio & mindszenty, 1995). some bauxite occurrences in northern istria were exposed to reduced pore waters during the subsequent transgression, resulting in the reduction of iron oxides and the precipitation of iron sulphides. in some cases entire bauxite bodies were exposed to this process, resulting in their complete transformation into grey and pyritised bauxite, as observed in the minjera bauxites. the transgression was marked by deposition of the palaeogene kozina beds directly overlying the bauxites, deposited in freshwater and brackish ponds developed in a network of bauxite-filled sinkholes, empty palaeodepressions, and vadose canyons. the kozina beds in this area consist of a sequence of bituminous, gastropod-rich limestones with some coal seams. the presence of charophyte oogonia in most layers confirms a freshwater to brackish-water depositional environment, although their alternation with layers abundant in milliolids indicates periodic marine incursions during their deposition (šinkovec et al., 1994). the kozina beds are overlain by foraminiferal limestones, indicating a gradual transition to open marine environments on the slopes of the newly formed pazin foreland basin to the south. 4. materials and methods after detailed investigation of all deposits from the minjera locality, only two deposits (d-1 and d-15; fig. 2) were deemed suitable for further investigation, since they still contained enough unweathered bauxite. these two deposits were selected for sampling, with the addition of the red bauxite sample from the tailing heaps left by the historic mining activity, which was found next to the d-14 deposit (fig. 2). in the d-15 deposit most bauxite samples were collected from the sides of the deposit, as most of the bauxite was completely mined out. two smaller profiles (profile 1 – fig. 2a: d15-1, d15-2, d15-3 and d15-10, profile 2 – fig. 2b: d15-5, d15-6, d15-7 and d15-8) encompassing the upper metre of the bauxite were sampled, as well as a portion close to the bedrock (d15-4), and the top section of the bauxite in the adit (d15-9). in the d-15 deposit, the footwall and the hanging wall of the bauxite were sampled over a total thickness of 6.1 m (figs. 4, 6c). in the d-1 deposit, samples were collected in the lower section of the deposit, as the upper section was not accessible. most of the samples were collected on the eastern side of the deposit (d1-1 to d1-9, fig. 6), while additional samples were collected from the central part of the deposit (d1-10 to d1-12; fig 6d). in this deposit, only the bedrock of the deposit was sampled. red bauxite was collected from tailing heaps near one of the historic processing plants (fig. 2), as it was previously located in the centre of the pyritised deposits but it was mined out from all deposits (šinkovec et al., 1994). thin-sections were prepared from all the limestone and bauxite samples. additionally, thin-sections were made from separated heavy and light mineral fractions using sodium polytungstate (spt) solution (3.0 g/cm3) after obtaining granulometric fractions ranging from 250 to 63 μm from both the grey and the red bauxite. prior to sieving, iron oxides from the red bauxite underwent dissolution using the dithionitecitrate-bicarbonate method (mehra & jackson, 1960) to release individual mineral grains. all thin sections were figure 1. geological map of the istrian peninsula and its position in europe. a – geological map of istria, modified after velić et al. (1995) with the schematic geological column. legend: m1 – 1st megasequence (lower bathonian–lower kimmeridgian); m2 – 2nd megasequence (upper tithonian–lower/upper aptian); m3 – 3rd megasequence (lower/upper albian– upper santonian); m4a – carbonate deposits of the 4th megasequence (mostly lower–middle eocene); m4b – clastic deposits of the 4th megasequence (middle–upper eocene); q – quaternary deposits. position of the palaeogene bauxites on the schematic geological column is indicated by a red arrow. (b) map of central, western and southern europe with the indicated location of istrian peninsula. (c) map of buzet area and geographic position of the minjera bauxites. figure 2. geological map of the minjera area with different types of bauxite deposits indicated, modified after šinkovec et al (1994). legend: 1 – upper cenomanian limestones; 2 – palaeocene kozina beds; 3 – eocene foraminiferal limestones; 4 – quaternary; 5 – red bauxite tailing heaps; 6 – sinkhole bauxite deposits; 7 – small canyon bauxite deposits; 8 – large canyon bauxite deposits; a – remnants of the processing plants and infrastructure from the past mining activities. g eo lo gi a c ro at ic a 162 geologia croatica 77/2 analysed using the optika b-1000 series polarizing microscope, equipped with the optika c-p6 fl camera and optika proview software. bauxites were analysed following the micromorphological and petrographic methodologies outlined by bardossy (1982), while sedimentological and micropalaeontological analyses of limestone sections were performed according to flügel (2004). for the additional study of iron sulphide morphology and general mineralogy sem-eds was employed on three samples, using the tescan vega gmu sem. eds analysis was also used, and was available using live sem scanning window of essence™ software using a fully integrated energy dispersive x-ray spectroscopy (eds) detector. x-ray powder diffraction (xrpd) analysis was conducted on most bauxite samples. a portion of each sample was gently crushed and sieved through a 0.5 mm sieve. subsequently, samples were milled in a mccrone micronizing mill for 15 minutes with a mixture of 2 ml of the sieved material and 7 ml of isopropyl alcohol. the resulting slurry was air-dried and disaggregated in an agate pestle and mortar. dried samples were side-loaded to ensure random orientation and uniform grain size, essential for accurate rietveld refinement. rietveld refinement was performed using profex version 5.2.4 software (doebelin & kleeberg, 2015), utilizing structural data from built-in files and the crystallography open database (graulis et al., 2009). to determine concentrations of major, minor, trace, and rare earth elements, five bauxite samples from both deposits and one red bauxite sample were selected. these samples were analysed using inductively-coupled-plasma mass-spectrometry (icp-ms) at the bureau veritas, canada commercial laboratory. analysis was performed using the lithium metaborate/tetraborate fusion and nitric acid digestion. total sulphur and carbon values were measured separately from other major oxides. trace element and rare earth element (ree) values were normalized to the upper continental crust values according to taylor & mclennan (1985). samples from both deposits were selected for stable sulphur isotope analysis. the procedure started with silver sulphide extraction from pyrite in the samples using the chromous chloride distillation method (canfield et al., 1986). sulphur-isotope analysis was undertaken on the resulting silver sulphide precipitates, which was performed on an elementar vario pyro cube linked to a gv isoprime mass spectrometer in continuous f low mode, in the cohen geochemistry laboratories of the school of earth and environment, university of leeds. about 0.150 mg of silver sulphide was weighed and packed into tin cups, which was afterwards flash-combusted at 1150 °c in the presence of pure research grade o2 and helium carrier gas to produce so2. excess o2 was consumed by reaction with copper wires at 850 °c and water was removed by a sicapent trap. subsequently, so2 was separated from other gases using a temperaturecontrolled trap and purge column. results were calibrated to the vienna-canyon diablo troilite (v-cdt) using a seawater laboratory standard (sws-3) and a chalcopyrite inter-lab standard (cp1), with their respective values of +20.3 and -4.56 ‰, respectively. the calibration of this material was in turn performed using the iaea s-3 (-32.06 ‰) international standard. figure 3. plans of the d-1 and d-15 deposits with their respective cross-sections and sampling sites. note that the b–b' and c–c' cross-sections are enlarged with respect to both plans and a–a' cross-section, in order to demonstrate the sampled profiles and sample positions more clearly. g eologia c roatica 163perković et al.: tracing the evolution of the world's first mined bauxite from palaeotopography to pyritization: insights from minjera deposits ... 5. results 5.1. outcrop and field descriptions 5.1.1. bauxite bedrock and cover – lithostratigraphy and biostratigraphy the minjera section comprises the 3.6 m thick succession of upper cenomanian beds underlying the regional unconformity and the d-15 bauxite deposit, and the 3.4 m thick palaeogene beds overlying the bauxite (fig. 4). based on the macroand microscopic lithological and microfossil features, four lithofacies types (lf1–lf4) were differentiated (fig. 4). peloidal-bio-intraclastic wackestone–packstone to packstone– grainstone with small benthic foraminifera, fragmented and micritized bivalve shells and in places small pelagic bioclasts figure 4. a stratigraphic column of the minjera section (d-15 bauxite bedrock and cover) with structures, fossil content, lithofacies and biostratigraphy. g eo lo gi a c ro at ic a 164 geologia croatica 77/2 (lf1), in the lower part of the cenomanian strata indicate formation in subtidal environments of an inner carbonate platform, with occasional input of material from the open sea (fig. 5a, b). the upper part of the cenomanian strata comprises peloidal-bioclastic mudstone–wackestone and wackestone–packstone with similar fossil content (lf2), but the presence of fenestrae, circumgranular cracks and pedotubules indicates shallowing of the depositional environment (very shallow subtidal and intertidal) and occasional subaerial exposures preceding the prolonged terrestrial phase marked by the regional unconformity (fig. 5c–e). a microfossil assemblage composed of various benthic foraminifera, among which the most important taxa are chrysalidina gradata, nezzazata simplex, pseudolituolunella reicheli, trochospira avnimelechi, pseudonummuloculina sp., and cuneolina pavonia, indicates the upper cenomanian age of the strata underlying the regional unconformity at the studied minjera locality (fig. 4). the irregular unconformity and the d-15 bauxite deposit is overlain by decimetre-thick beds of brownish to dark grey lacustrine limestones (lf4; figs. 4, 6c), which include centimetreto decimetre-thick coal interbeds in their base, formed in freshwater marsh (lf3; fig. 5f). the contact between the bauxite and the cover sequence is marked by dark brown, organic matterand coal-rich bauxite mixed with large carbonate pebbles and in places boulders likely eroded from the surrounding carbonate rocks and embedded within the top sections of the bauxites during the initial flooding of the area. in their lower part, the lacustrine limestones are composed of green algal (cladophorites) wackestone with gastropod shells and rare small rotalids indicating lacustrine near-shore and shore depositional settings (lf4a; fig. 5g, h). the middle part is composed of wackestone with cladophorites, gastropod shells, decastronema, ostracods, and discorbids commonly with pedotubules and in places desiccation cracks, indicating a lake shore environment with plants (lf4b; fig. 5i). in the figure 5. photomicrographs of the lithofacies (lf) in the minjera bauxite bedrock and cover. a – lf1: peloidal packstone-grainstone with benthic foraminifera (sample mi-6). b – lf1: peloidal-bio-intraclastic packstone-grainstone (sample mi-10). c – lf2: bioclastic mudstone with circumgranular cracks and rare benthic foraminifera (sample mi-8). d – lf2: fenestral peloidal mudstone-wackestone with rare benthic foraminifera (sample mi-16). e – lf2: indistinctly laminated peloidal-bioclastic wackestone with pedotubules (sample mi-17). f – lf3: laminated coal with iron ooids (pisoids) ( sample mi-20). g – lf4a: laminated green algal (cladophorites) mudstone-wackestone (bafflestone) with gastropod shells (sample mi-22a). h – lf4a: laminated green algal (cladophorites) mudstone-wackestone with gastropod shells and rotalid foraminifera (sample mi-23). i – lf4b: decastronemaostracod-discorbid wackestone (sample mi-24a). j – lf4c: discorbid-charophycean wackestone (sample mi-34). k – lf4c: discorbid-charophycean wackestone with wood fragments (sample mi-34). size of the scale bar is 1 mm on all photomicrographs. g eologia c roatica 165perković et al.: tracing the evolution of the world's first mined bauxite from palaeotopography to pyritization: insights from minjera deposits ... upper part of the lacustrine limestones, charophyceandiscorbid wackestone prevails with discorbids, charophycean oogonia and thalli parts, cladophorites, gastropod and ostracod shells, and in places wood fragments (lf4c; fig. 5j, k). such fossil remains indicate similar lacustrine near-shore settings including brackish environments of a coastal lake. small rotalid foraminifera often present in thin laminae in all lithofacies were probably transported by storm events from neighbouring marine environments. the microfossil assemblage including bangiana hanseni, kayseriella decastroi and fragments of pachycolumella indicates a palaeocene age of the strata directly overlying the d-15 bauxite deposit at the studied minjera locality (fig. 4). 5.1.2. description of bauxite deposits three main deposit types were distinguished based on field observations (fig. 2): the large canyon (elongated, deeper than 10 metres and between 20 and 40 metres in its longer axis), small canyon (elongated, less than 10 metres deep with the longer axis shorter than 20 metres) and sinkhole deposits (spherical, less than 10 metres deep and smaller than 10 metres in diameter). most of the smaller canyon and sinkhole deposits are located south of the mirna river, while most of the large canyon deposits are located north of the mirna river. the d-1 deposit is of the large canyon type, being very steep, almost 40 metres long and thicker than 15 metres (figs. 2 and 3), while the d-15 deposit represents the smaller canyon type, as it is less steep, up to 20 metres long and up to five metres thick (figs. 2 and 3). the bauxite from these two deposits also differs macroscopically, with those from the d-15 being mostly grey (fig. 6a and b) and those from the d-1 deposit being darker due to the higher pyrite content (fig. 6d and f). coalrich bauxite can be found on top of the bauxite in both d-1 (fig. 6a and b) and d-15 deposits, but it has only been sampled in the d-15 deposit. in the d-15 and other deposits, it can be seen that a number of carbonate clasts are embedded within the bauxite in its uppermost part (fig. 6a and b). several pyritised bauxite types can be discerned visually: the “striped” or “spotted” bauxite composed of a grey matrix within which large veins or spots of iron sulphides are visible (fig. 6g), grey bauxite containing visibly very little pyrite (fig. 6a, b, d, f), and black bauxite completely impregnated with iron sulphides (fig. 6d and f). pyritised root relics have also been observed but only in the grey bauxite from the d-15 deposit. 5.2. petrography and micromorphology all bauxite samples from d-1 and d-15 deposits as well as sampled red bauxite have oolitic texture (fig. 7a−f), with varying proportions of ooids (sensu bardossy, 1982) and the pelitomorphic matrix. the ooids in the red bauxite are between 50 and 200 µm in size, composed of iron oxide-rich and oxide-poor laminae, with the majority having an iron oxide-poor outer cortex (fig. 7a). large bauxite clasts can also be found in the red bauxite (fig. 7a), which are usually richer in iron oxides than the surrounding matrix, but occasionally have a deferrified outer rim. the aforementioned iron oxide enrichment and depletion in clasts and ooids was preserved through pyritisation in samples from both the d-1 and d-15 deposits, as the pyritised ooids display an alternation of pyriterich and pyrite-poor laminae (fig. 7b), while bauxite clasts commonly contain more iron sulphides than the surrounding matrix (fig. 7c). in places, in the d-15 deposit, the ooids are figure 6. photographs of the sampled profiles and sample positions. a – profile 1 in the d-15 deposit with sample locations, composed of grey and coal-rich bauxite; b – profile 2 in d-15 deposit with sample locations, composed of grey and coal-rich bauxite; c – bauxite hanging wall composed of kozina limestones in the d-15 deposit, with indicated position of the sampled hanging wall; d – profile 1 in the d-1 deposit with indicated sample positions; e – entrance into the adit exposing d-1 deposit with indicated sample positions on the second profile; f – zonation of pyrite-poor and pyrite-rich bauxite with indicated sample positions; g – “striped“ and “spotty“ bauxite, composed of pyrite-poor bauxite and veins or spots of pyrite-rich bauxite. g eo lo gi a c ro at ic a 166 geologia croatica 77/2 completely replaced by kaolinite (fig. 7b). organic matter and coal were also detected, but only in the coal-rich bauxite, alternating with reworked bauxite clasts and ooids (fig. 7d). the samples from the d-15 deposit contain less aluminium oxide minerals than those from the d-15 deposit. the aluminium oxide minerals are diaspore and boehmite in both deposits. these two minerals make up the iron-poor laminae in ooids (fig. 7e) and they are also likely present in the cryptocrystalline matrix. besides the ooids, diaspore is also present in veins or nests (fig. 7f). the two deposits also differ in their iron sulphide content, the d-1 deposit contains much more iron sulphide, while the d-15 deposit contains less iron sulphide. the iron sulphides are mainly present as pyrite in both deposits with the sporadic occurrence of marcasite. pyrite displays an array of different morphologies, most of which are present in both deposits. it is present as framboids with a diverse size range between 5 and 40 µm, which are either present individually in the matrix (fig. 8a), or are aggregated (fig. 8c) and concentrated within the pores between ooids or in the matrix. framboids are commonly associated with micrometre-sized anhedral pyrite (msap, fig. 8b), which also impregnates large portions of the bauxite matrix in some samples (figs. 4c and d), as well as ooid lamellae and bauxite clasts (fig. 8d). both the framboids and msap are frequently overgrown with colloform pyrite, which is present as: 1 – impregnations of msap (fig. 8d), 2 – thin overgrowths of individual framboids (fig. 8a), and 3 – large-scale impregnations, overgrowths and replacements of msap and framboids in the matrix (fig. 8c), ooid laminae (fig. 8d) or bauxite clasts. colloform pyrite also forms banded textures in places and is commonly overgrown with euhedral pyrite (fig. 8f). euhedral pyrite can be also found as a replacement of individual framboids within the matrix (fig. 8e), preserving their original size and shape, dominated by octahedrons and hexahedrons (fig. 8e). dendritic pyrite was also observed, mainly present as overgrowths over euhedral pyrite (fig. 8g). acicular pyrite also formed in some samples and is exclusively present in the bauxite matrix (fig.8h). the pyrite veins were found in most samples, cross-cutting other pyrite features and structural elements (fig. 8i and j). pyritised root remains were found in the samples from the d-15 deposit, composed of hollow tubes of colloform or euhedral pyrite, filled with matrix material or some authigenic phase such as diaspore or kaolinite (fig. 8l). besides pyrite, marcasite was also found, but mostly in rosettes composed of elongated crystals smaller than 100 µm (fig. 8k). extracted light and heavy mineral fractions were also studied: in the heavy mineral fraction staurolite, gruneritecummingtonite, tourmaline and barite were detected (figs. 9a–d), while chert and opal were detected in the light mineral fraction (figs. 9e and f). most of the minerals from the heavy mineral fraction and chert are rounded to subrounded, while only barite displays some euhedral grains. opal is found as irregular masses and shards, indicating its authigenic origin. 5.3. xrpd the mineralogical composition was primarily analysed using xrpd, as most phases in bauxites are hard to identify microscopically due to their cryptocrystalline occurrence. clear differences in mineralogy were found between the d-1 and d-15 deposits, with the samples from the d-1 deposit containing much higher amounts of pyrite and boehmite figure 7. photomicrographs of red, pyritised and coal-rich bauxite in plane-polarised (ppl)b or cross-polarised light (xpl). a – red bauxite with numerous ooids with visible deferrification in their cortices or lamellae, and a clast of iron-oxide rich oolitic bauxite (1), sample rb (ppl); b – kaolinitised and pyritised ooids, sample d1-3 (xpl); c – pyritised oolitic bauxite with a completely pyritised bauxite clast (2), sample d15-9 (ppl); d – coal-rich bauxite, composed of fan-like alternation of coal intercalations (3), reworked bauxite material and ooids, with the coal lenses cross-cut by gypsum veins, sample d1-6 (ppl); e – pyritised bauxite with visible ooids composed of boehmite, sample d1-3 (xpl); , f – pyritised bauxite clast and diaspore veins (4) and nests (5), sample d15-9 (ppl). g eologia c roatica 167perković et al.: tracing the evolution of the world's first mined bauxite from palaeotopography to pyritization: insights from minjera deposits ... compared to samples from the d-15 deposit, which mostly have a lower boehmite content and higher kaolinite content (fig 10). based on this, samples from the d-1 deposit are genuinely bauxites while the ones from d-15 deposit are clayey bauxites. in both deposits, variable amounts of diaspore and marcasite are present, together with anatase, rutile and different secondary sulphate minerals such as pickeringite, jarosite and gypsum. red bauxite differs from those samples since it is composed mainly of boehmite and haematite with smaller amounts of kaolinite, anatase and rutile. 5.4. geochemistry and stable sulphur isotopes the major oxide content of the studied samples is in accordance with their mineralogical composition, with the pyriteand boehmite-rich samples from the d-1 deposit having a higher amount of fe2o3, loi, na2o and tot/s, while the kaoliniterich samples from the d-15 deposit have higher amounts of cao, k2o, mgo, mno and sio2 (fig. 11). the d15-6 sample is an exception in the d-15 deposit, as it has a lower content of the aforementioned elements and is enriched in tot/c (fig. 11), indicating its high organic matter content, which corresponds to the abundance of coal in that sample (fig. 7d). compared to samples from both the d-1 and d-15 deposits, red bauxite has a higher cr2o3 and mno and lower loi, na2o, p2o5 and tot/s values (fig. 11). the ternary diagram sio2–al2o3–fe2o3 (after aleva, 1994) also highlights the differences between the two deposits (fig. 12), as most of the samples from the d-15 deposit are kaolinitic bauxites or pure figure 8. photomicrographs taken using xpl or reflected light (rl) and bse images of different iron sulphide morphologies. a – pyrite framboids (1) overgrown with colloform pyrite, sample d15-10 (rl); b – dispersed grains of msap (2) in the bauxite matrix, sample d15-10 (bse); c – mixture of pyrite framboids and msap (3) overgrown with colloform pyrite (4), sample d1-12 (rl); d – photomicrograph of pyritised ooids and bauxite matrix impregnated with msap (5), with visible impregnations of colloform pyrite (5) and replacement of msap with colloform pyrite in ooid lamellae (6), sample d13 (rl); e – individual euhedral pyrite crystals in the bauxite matrix, sample d1-3 (bse); f – colloform pyrite (7) overgrown with euhedral pyrite crystals with visible growth bands (8), sample d15-10 (bse); g – euhedral pyrite crystals (9) overgrown with dendritic pyrite (10), sample d15-10 (bse); h – acicular pyrite crystals in the bauxite matrix, sample d1-6 (rl); i – veins composed from pyrite and kaolinite (11), sample d1-8 (rl); j – ooid cross-cut by pyrite veins (12), sample d1-9 (rl); k – marcasite rossete (k) in bauxitic matrix with different pyrite morphologies, sample d15-10 (rl); l – pyritised root filled with diaspore crystals (14), sample d15-8 (xpl). g eo lo gi a c ro at ic a 168 geologia croatica 77/2 bauxites, while those from the d-1 deposit are ferritic bauxites or pure bauxites. the red bauxite falls in the ferritic bauxite field. the differences between the deposits and sample types are also visible in the trace element contents. the samples from the d-1 deposit are enriched in as, cu, co, ni and sb when compared to the d-15 deposit and red bauxite, while the samples from the d-15 deposit are enriched in ba, cs, rb, sr, u and zn compared to d-1 deposit and red bauxite (fig. 13). samples from both deposits are enriched in cd, hg, mo, se and tl, as well as depleted in bi, ga, nb, sn, ta, th, v and zr compared to the red bauxite sample (fig. 13). red bauxite has a higher ga, nb, pb, sn, ta, th, v and zr content than samples from d-1 and d-15 deposits (fig. 13). while showing some similarities to other samples from the d-15 deposit, the coalrich bauxite shows several differences – higher hg, mo and sb values and lower values of co, cs, cu, ni, pb, th and tl (fig. 13). compared to the upper continental crust, all samples are enriched in as, ga, hf, hg, nb, ni, sb, sn, u, v, w, y and zr, while being depleted in ba, rb, se and sr (fig. 14a). rare earth elements display similar trends in all sample types with few variations. generally, all samples display a “saddle” pattern, with a visible depletion in middle rare earth elements (mree) compared to light (lree) and heavy rare earth elements (hree, fig. 14b–d). red bauxite has a higher hree and mree content than the samples from the d-1 and d-15 deposits, and a pronounced negative ce anomaly (fig. 15). samples from the d-1 and d-15 have the same ree patterns (fig. 14b, c), but the samples from d-15 deposit have higher lree values, total ree values and la/y ratios, as well as lower y/ho ratios (figs. 14b, c and 15). the d15-6 differs from the rest of the samples from the d-15 deposit in rees as well, having lower lree values and la/y as well as higher y/ho values (figs. 14c and 15). both deposits display either very low negative ce anomalies or their absence (fig. 15). δ34s values do not display any apparent differences between the deposits and their position within them (fig. 16). their values range between -40.86 to 2.32 ‰ (fig. 16). 6. discussion 6.1. genesis of the minjera deposits the minjera bauxites were developed over the karstified upper cenomanian limestones which announced the subaerial exposure phase, partly through the shallowing of the depositional environment and the repeated occurrence of brief subaerial exposure surfaces and partly by features such as fenestrae, circumgranular cracks and pedotubules. finally, the start of the subaerial exposure phase is indicated by the formation of the minjera bauxites in the studied area. the source and the type of material from which the minjera figure 9. photomicrographs of different mineral grains from the light and heavy mineral fractions in ppl. a – staurolite, b – cummingtonite-grunerite group amphibole, c – tourmaline, d – baryte, e – chert, f – opal. figure 10. mineralogical bulk composition of samples analysed using xrpd. g eologia c roatica 169perković et al.: tracing the evolution of the world's first mined bauxite from palaeotopography to pyritization: insights from minjera deposits ... bauxites have formed is hard to determine, since bauxitisation leads to the loss of primary textures, structure and composition of the parent material. nevertheless, the material from which these bauxites formed can be tentatively reconstructed based on the content of the light and heavy mineral fractions. the presence of metamorphic minerals such as staurolite, tourmaline and clinohumite-grunerite amphiboles (fig. 5a–d) indicate the contribution of a mixture of aeolian material during its formation. the insoluble residue from the underlying carbonates can neither be confirmed nor disputed and should be regarded as a possible minor source of the parent material. karst bauxites are also commonly formed from volcanic dust (bardossy, 1982; d’argenio & mindszenty, 1995; kelemen et al., 2017, 2023; brlek et al., 2021), but there is no evidence for such an input in the case of the minjera bauxites, as no zircons have been found which could have been dated and connected to contemporaneous volcanic activity. the deposition and accumulation of source materials for the bauxites was initiated by the tectonic deformation of the adriatic carbonate platform in response to the load of the advancing nappes following the closure of the vardar ocean at the end of the cretaceous (van hinsbergen et al., 2020; schmid et al., 2008, 2020). following this, karstification also ensued, creating a diverse karst landscape, as seen by the different morphologies and sizes of the minjera deposits (fig. 2). the prevalence of large canyon deposits north of the mirna river and their absence south of the river coupled with the abundance of sinkhole and smaller canyon deposits (fig. 2) suggests the geomorphological differences between these two areas. the kozina beds are also much thicker south of the mirna river (fig. 2), indicating altogether the lower palaeotopographical position of the deposits on the southern side compared to the northern side, which resulted in the formation of deeper karstic features on the northern side. this is reflected in the mineralogical and geochemical composition of the two studied bauxite deposits, as the differences in the morphology of the deposits affected the drainage and the intensity of fluid-flow of percolating porewaters. the larger and steeper d-1 deposit has a higher boehmite content compared to the d-15 deposit, and is composed of bauxite and ferritic bauxite (fig. 12). the d-15 deposit contains more kaolinite (fig. 10) and is composed of bauxite and kaolinitic bauxite (fig. 12), which is probably a result of better drainage and higher distance from the water table in the d-1 deposit and vice-versa. the clear relationship between bauxites and their palaeotopographical position was described by d’argenio & mindszenty (1995) and has also been observed in other studies (yang et al., 2017; mo et al., 2023), indicating that the bauxite lithofacies and grade depend on their position in the karst terrains. based on this, the bauxites on the northern side of the mirna river can be attributed to the vadose bauxite lithofacies, while those from the southern side represent the intermediate bauxite lithofacies sensu d’argenio & mindszenty (1995). diagenetic resilicification is a figure 11. values of different major oxides plotted against individual samples. figure 12. a bauxite classification diagram based on al2o3 fe2o3 and sio2 content according to aleva (1994). 1 – bauxite, 2 – kaolinitic bauxite, 3 – ferritic bauxite, 4 – laterite, 5 – bauxitic kaolinite, 6 – kaolinite, 7 – ferritic kaolinite, 8 – bauxitic ferrite, 9 – ferrite, 10 – kaolinitic ferrite, 11 – ferrite. g eo lo gi a c ro at ic a 170 geologia croatica 77/2 common phenomenon in bauxites after their formation (bardossy, 1982; mameli et al., 2007; mongelli et al., 2021) and should not be excluded as a factor resulting in the higher kaolinite content of the d-15 deposit, as the replacement of boehmite with kaolinite in ooids can be seen in some samples (fig. 7b). veins filled by an association of pyrite and kaolinite crystals were also found (fig. 8i) in both deposits, indicating that resilicification was also present in the d-1 deposit. diaspore also formed during this phase, replacing boehmite in the bauxite matrix and within the ooids but also forming nests within the pyritised roots and the bauxite as well as in veins (figs. 7f and 8l). diaspore can form in several ways, either in response to increasing pressure during burial diagenesis (bardossy, 1982; williams, 2014; gamaletsos et al., 2017; mondillo et al., 2022), or it can form in the reducing environment (nia, 1968; bardossy, 1982; d’argenio & mindszenty, 1995; liu et al., 2013; zhang et al., 2022). in the case of minjera bauxites, it is clear that diaspore formation happened in reducing conditions, as it crystallised directly from percolating solutions, as indicated by its presence in nests and veins (figs. 7f and 8l). a proportion of diaspore might also be inherited from the originally red bauxite, as a minor amount of diaspore has been detected in the red bauxite (fig. 10). 6.2. iron sulphide morphology and stable sulphur isotopes a large number of iron sulphide morphologies were found in the minjera bauxites, the formation of which was initiated as the microbial sulphate reduction and dissolution of iron oxides figure 13. values of different trace elements plotted against individual samples. figure 14. values of trace elements and rare elements in different samples after normalisation against the upper continental crust. a – values of trace elements, b – values of rare earth elements in the d-1 deposit, c – values of rare earth elements in the d-15 deposit, d – values of rare earth elements in the red bauxite. g eologia c roatica 171perković et al.: tracing the evolution of the world's first mined bauxite from palaeotopography to pyritization: insights from minjera deposits ... began in a newly established marshy environment. macroscopically, they exhibit several different types across the two studied deposits, where they form bands and nodules within the iron-poor bauxite matrix in the cases of “striped” and “spotted” pyritised bauxites (fig. 6g). this can be linked to the differences in the redox potential and the degree of pyrite saturation in the porewaters, allowing its crystallisation in spots or bands, with the bands of the “striped” bauxite being controlled by the direction of fluid-flow. in the case of the d-1 deposit, a zonal arrangement of pyrite-rich and pyrite-poor bauxite was observed, with the increase of pyrite content towards the interior of the deposit, with the completely pyritised region separating the zone with less and more pyrite (fig. 6f). this zonation is parallel to the karstified bedrock and is probably a result of changes in the redox potential, with the completely pyritised zone likely indicating the redox boundary, where conditions for iron sulphide precipitation were apparently optimal. this could also reflect the ph differences within the sediment, as the inflow of saline and karstic porewaters during the flooding of the bauxite was the highest in this zone, where the pyrite-rich zone could reflect the zone with near-neutral to slightly alkaline conditions which are generally required for its formation (wilkin & barnes, 1996). on the micro-scale, there is a clear order in the formation of different iron sulphide morphologies (figs. 17 and 18). the first pyrite morphologies that formed (figs. 17 and 18) were the framboidal pyrite and the impregnations of msap (figs. 8a–d), which formed in the pore spaces, in the matrix (figs. 8b, 8d and 18a), as a replacement of roots (figs. 8l and 18a), or as an in-situ replacement of originally iron oxide-rich bauxite clasts and ooid lamellae (figs. 7b, 7c and 18a). it should be noted that pyrite framboids were also found in other pyritised bauxites (laskou & economou-eliopoulos, 2007; zarasvandi et al., 2012; economoueliopoulos et al., 2022), appearing to be a common feature in pyritised bauxites. framboidal pyrite usually forms first from the initially precipitated iron monosulphides (berner, 1970; hámor 1994), which can then serve as crystallisation sites for later stages of pyrite growth (yue et al., 2020). as such, both the framboids and msap were overgrown by colloform pyrite (figs. 8a, c and d). the presence of both framboidal and colloform pyrite in the first two stages (figs. 17, 18a and 18b) indicates that the solutions were supersaturated with respect to pyrite (roedder, 1968; chen, 1978; barrie et al., 2009). it should be noted that the colloform pyrite also frequently displays a banded character, indicating the fluctuations in pyrite saturation during its precipitation (barrie et al., 2009). the formation of colloform pyrite was followed by the formation of euhedral pyrite which overgrows framboids as well as colloform pyrite (figs. 8f and 18c), and which replaces framboids with individual euhedral crystals (figs. 8e and 18c). the formation of euhedral pyrite indicates that the porewaters became undersaturated with respect to pyrite in this stage (raiswell, 1982; barrie et al., 2009; cavalazzi et al., 2012; he et al., 2022). they also commonly display distinct growth bands, where some of them contain matrix impurities (fig. 8f), indicating the fluctuations in growth rates. the further drop in pyrite saturation is figure 15. values of different ree groups, total ree content, ce anomaly and different ree ratios plotted against individual samples. g eo lo gi a c ro at ic a 172 geologia croatica 77/2 recorded via the precipitation of dendritic pyrite (barrie et al., 2009), which represents the final overgrowth on the previously deposited pyrite morphologies where present (figs. 8g and 18c). its formation is also coupled with the crystallisation of acicular pyrite (figs. 8h, 17 and 18c). the final pyrite deposition and late diagenesis is marked by the consolidation and brittle fracturing of the bauxite within which the final stage of iron sulphides precipitated as pyrite and kaolinite veins (figs. 8k, 8l, 17 and 18d). marcasite is found only as rosettes or radial crystal clusters which cannot be precisely related to any of the stages of pyrite formation (figs. 8k and 17). its presence indicates the local presence of acidic conditions within the deposit, as la/y ratios >1 indicate that the bauxites generally formed under alkaline to nearalkaline conditions (fig. 11; maksimović & pantó, 1991). stable sulphur isotope values indicate the role of microbial sulphate reduction in pyrite formation, as most of the δ34s values are negative (fig. 16). similar δ34s values were figure 16. the position of different δ34s values in the d-1 and d-15 deposits, together with the histogram of obtained δ34s values. figure 17. a paragenetic sequence of the minjera deposits and the succession of the formation of different iron sulphide morphologies. g eologia c roatica 173perković et al.: tracing the evolution of the world's first mined bauxite from palaeotopography to pyritization: insights from minjera deposits ... found in most pyritised bauxites where stable sulphur isotopes were studied (öztürk et al., 2002; laskou & economou-eliopoulos, 2007; zarasvandi et al., 2012; ellahi et al., 2015; zhao et al., 2023). the δ34s values from the minjera bauxite also display a wide range of values, from -40.86 to 2.32 ‰ (fig. 16), which compared to the global seawater 34s values between 17 ‰ and 19 ‰ during the late cretaceous and palaeocene (algeo et al., 2015) yield enrichment factors between -60 ‰ and -15 ‰. the high negative values indicate that the system was open, since the sulphate content was not limited, allowing the continuous enrichment of 32s via microbial reduction (chambers & trudinger, 1979; algeo et al., 2015; pasquier et al., 2017; hough et al., 2019). the sulphate-rich marine to brackish solutions were likely pumped through the underground karstic conduits and channels through tidal pumping, a common phenomenon which induces salinity changes in blue holes in the bahamas (martin et al., 2012; smith et al., 2021). on the other hand, the intermediate and lower values (fig. 16) indicate the shift towards a closed or partially open system in which the sulphate content was limited, which leads to utilisation of heavier 34s in microbial sulphate reduction, as the sulphate with 32s was depleted and not replenished (chambers & trudinger, 1979; algeo et al., 2015; hough et al., 2019; pasquier et al., 2021). this was also observed in other studies (zarasvandi et al., 2012; ellahi et al., 2015; zhao et al., 2023), and in the case of the minjera bauxites it can be related to their progressive and final burial, which led to the hydrological closure of this system. the progressive closure could also be related to the progressive undersaturation of pore solutions with respect to pyrite, as indicated by the presence of euhedral, dendritic and acicular pyrite in the later stages (figs. 8e–h, 17 and 17c), as the sulphur content became a limiting factor during its precipitation. 6.3. geochemistry of the minjera bauxites when comparing the trace element composition of the minjera bauxites with the upper continental crust values (taylor & mclennan, 1985), they are enriched in most trace elements such as lithophile and high field strength elements (hfse), while being depleted in large ion lithophile elements (lile, fig. 13). this is commonly observed in most bauxite deposits as elements such as hfse are retained during bauxitisation (mongelli, 1997; calagari & abedini, 2007; abedini & calagari, 2014; mongelli et al., 2014, ellahi et al., 2017; abedini et al., 2020) while the more mobile elements including bases and lile are leached away (mongelli, 1997; calagari & abedini, 2007; xiao et al., 2021). fractionation of trace elements changed figure 18. a schematic reconstruction of the succession of different iron sulphide morphologies. a – formation of msap in the bauxite matrix (1), bauxite clasts (2), root remains (3) and ooid lamellae, coupled with the formation of pyrite framboids (4) together with msap or individually in the bauxite matrix; b – overgrowth of colloform pyrite (6) over msap and framboids in the matrix, bauxite clasts, pyritised roots or ooid lamellae, which locally display banded textures (7); c – overgrowth and recrystallisation of framboids (8), msap and colloform pyrite into euhedral pyrite (9), followed by its overgrowth with dendritic pyrite (10) and formation of acicular pyrite in the matrix (11); d – formation of pyrite and kaolinite veins (12), over the previously formed iron sulphide morphologies and bauxite. legend: 1 – msap; 2 – bauxite clasts; 3 – pyritised root remains; 4 – pyrite framboids; 5 – bauxite matrix; 6 – colloform pyrite; 7 – banded colloform pyrite; 8 – replacement of individual framboids with euhedral pyrite crystals; 9 – euhedral pyrite overgrowths; 10 – dendritic pyrite overgrowths; 11 – acicular pyrite; 12 – kaolinite and pyrite veins. g eo lo gi a c ro at ic a 174 geologia croatica 77/2 during the reduction and pyritisation of the red bauxite, as the newly established reducing and hydrogen sulphide-rich environment led to the accumulation and enrichment of chalcophile and redox-sensitive elements such as cd, hg, mo, se, and tl (fig. 13). this also affected the content of trace elements such as pb and v which are preferentially enriched by iron oxides (wanty & goldhaber, 1992; tabelin et al., 2018; shaheen et al., 2019), released during their reduction and dissolution, leading to their depletion in the pyritised bauxites compared to the red bauxite (fig. 13). rees were also affected by this process, since there is a significant depletion in mrees within the pyritised bauxites (fig. 14b, c), which is linked to the dissolution of iron oxides during their reduction which usually enriched the mrees (tang & johannesson, 2003; grybos et al., 2007; laveuf et al., 2008; davranche et al., 2011; zhou et al., 2020). this is further supported by the higher mree content of the red bauxite sample compared to the pyritised bauxites (fig. 15), confirming that they were indeed leached during the dissolution of iron oxides. organic acids also preferentially adsorb mrees compared to other rees (grybos et al., 2007; pourret et al., 2007; davranche et al., 2011), which could have been the mechanism through which they were removed from the bauxite as the organic-rich marshy environment was established on top of the bauxite. this is more pronounced in the organic-matter rich d15-6 sample, where lrees and mrees are even more depleted (figs. 14c and 15). they also exhibit an enrichment in hg, mo, and sb, which can be linked to the higher organic matter content of this sample (figs. 13 and 14a). the pyritised bauxites also differ from red bauxite with respect to the ce anomaly, as the red bauxite displays a negative ce anomaly which is either weaker or absent in the pyritised bauxites (figs. 14b–c and 14). the ce anomaly in the red bauxite is likely a result of preferential retention of ce in the upper parts of the bauxite (mongelli, 1997; wang et al., 2013; vind et al., 2018), since this leads to the development of a negative ce anomaly in the lower sections of bauxites (mongelli, 1997). this negative anomaly could have been masked by the remobilisation of ce in the presence of organic matter and acids during the flooding of the bauxite. this process preferentially concentrated ce (pourret et al., 2008; davranche et al., 2011), because this could have caused its redistribution in the pyritised bauxite, masking the previously developed ce anomalies. the trace elemental content also supports the differences between the d-1 and d-15 deposits discussed in section 6.1, as besides the aforementioned differences in major elements between the deposits, the d-15 deposit also displays higher values of leachable elements such as ca, k, mg, mn and lile compared to d-1 (figs. 12 and 13), which is in turn enriched in chalcophile elements such as as, cu, co, ni and sb (fig. 13), indicating their association with iron sulphides which are much more abundant in the d-1 deposit. the higher y/ho ratio in the d-1 deposit compared to the d-15 deposit (fig. 15) also indicates its higher degree of leaching, as this ratio can be used as a proxy for the intensity of water–rock interactions in soils (ji et al., 2004; feng, 2010), since ho is more mobile than y in the aqueous environment (bau et al., 1997; diakonov et al., 1998) and complexes more easily with organic matter and hco3 (kawabe et al., 1991). the higher content of leachable elements in the d-15 deposit is also related to the greater alkalinity in this deposit, indicated by the higher la/y values compared to the d-1 deposit (fig. 15), which are commonly used as ph proxies in bauxites, with values >1 indicating formation under alkaline condit ions (maksimović & pantó, 1991). the increased alkalinity is also evident from the higher total ree content in the d-15 deposit (fig. 15), as rees are more stable in alkaline solutions (cao et al., 2001; ferreira da silva et al., 2009; olías et al., 2018). 6.4. bauxite cover sequence the palaeocene lacustrine limestone cover sequence began with coal intercalations overlying the dark brown bauxite rich in organic matter, altogether indicating the flooding of a previously exposed karst terrain. the topmost section of the bauxite is commonly intermixed with carbonate clasts and boulders (fig. 6a, b), which were likely eroded from the surrounding carbonate rocks and embedded within the bauxites during the initial flooding. the first part of the cover sequence was deposited in a lacustrine environment with typical flora and fauna composed of fresh water green algae cladophorites, ostracods, gastropods and charophyta. the strengthening of a marine influence is visible upwards in the cover sequence through the common presence of benthic foraminifera. this phase is linked to the internal transgression of the exposed carbonate terrain, which was later followed by overland transgression, during which the fully marine foraminiferal limestones were deposited. the evolution of the bauxite cover from restricted lacustrine, brackish and freshwater environments towards fully marine carbonate deposition can be described as a typical “blue hole” sequence (rasmussen & neumann, 1988, carannante et al., 1994a, b). the presence of coal-seams, organic matter and plant remains in the top sections of the bauxite and the rest of the cover sequence confirms the establishment of a marshy environment on top of the bauxites, which served as a source of organic matter for microbial sulphate reduction. 7. conclusions this study focused on the genesis of the historically important minjera bauxites, situated in the western part of the savudrija– buzet anticline, which developed during the subaerial exposure phase that marked the end of the cretaceous and palaeocene periods in istria. this was done using the trace and rare earth elements as proxies for the physicochemical changes during the formation of the studied bauxites, as well as stable sulphur isotopes and iron sulphide morphology. this study also focused on the evolution of the cover in the studied bauxite deposits, in order to reconstruct the immediate palaeo environmental changes that followed the subaerial exposure phase. several conclusions can be drawn from the collected data and their interpretation: 1 – the parent material from which the minjera bauxites developed was polygenetic in origin, and was accumulated and bauxitised in karstic canyons and sinkholes developed over upper cenomanian limestones the shallowing trend g eologia c roatica 175perković et al.: tracing the evolution of the world's first mined bauxite from palaeotopography to pyritization: insights from minjera deposits ... of which and subaerial exposure features anticipated the long-lasting subaerial exposure phase during which the istrian palaeogene bauxites developed. 2 – the pyritisation of the minjera bauxites produced geochemical differences between the originally red bauxite and the pyritised bauxite, as chalcophile elements were enriched during pyritisation under euxinic conditions, while the mrees, v, and pb were dissolved and depleted as a consequence of the solubilisation of iron oxides. 3 – petrographic, mineralogical and geochemical differences were observed between the d-1 and d-15 deposits, as the d-1 deposit contains more pyrite, boehmite, chalcophile elements and a higher y/ho ratio, while the d-15 deposit formed in more alkaline conditions, and contains more kaolinite as well as more leachable elements such as lile, mn, ca, mg and k. based on this, the d-1 deposit is of the true vadose type, which formed in a higher palaeotopo graphical position and higher above the water table compared to the d-15 deposit, which exhibits some features of phreatic bauxites and was formed in a lower palaeotopographic position, closer to the water table. 4 – pyritisation in the minjera bauxites was a multi-stage process. in the first phase, micrometre-sized anhedral pyrite and pyrite framboids were formed, which were later overgrown and replaced by colloform pyrite in the second phase, where all of these morphologies indicate that the solutions were supersaturated with respect to pyrite. in the following stages, euhedral, dendritic, and acicular pyrite formed, indicating that the solutions became undersaturated with respect to pyrite. the final stage of pyritisation is marked by the formation of pyrite veins. 5 – stable sulphur isotopes support the diagenetic evolution of the system outlined by pyrite morphologies, as the δ34s values exhibit a large range between -40.86 and 2.32 ‰. this indicates the evolution from an open system, during which the sulphate source was not restricted and the solutions were supersaturated with respect to pyrite, towards a closed system as the bauxite deposit was being progressively buried and more isolated, in which the sulphate supply was limited, leading to the drop in saturation of the solutions with respect to pyrite. 6 – the cover sequence of the bauxite is of palaeocene age and can be described as a “blue hole” sequence, typical for the internal transgression of karst terrains, as it exhibits the transition from lacustrine conditions, characterised by fresh water green algae, charophyta and ostracods, towards a more marine environment indicated by the appearance of benthic foraminifera, before transitioning into the fully marine foraminiferal limestones. based on the above, this study significantly added to the previous knowledge of the historically important minjera bauxites, as it provides novel insight into their genesis and subsequent pyritisation. the detailed reconstruction of the different stages of their subsequent pyritisation is also a valuable addition to the current knowledge on pyritisation in bauxites, as few studies distinguished and described the pyritisation of a bauxite deposit in such detail. this study also revealed that the local differences in palaeorelief on subaerially exposed karst terrains can produce bauxites of different morphology and mineralogy, as well as different geochemical signatures. the important contribution is also the determination of the cover of minjera deposits as palaeocene, which is a new finding in the studied area. acknowledgement this work has been fully supported by the croatian science foundation under the project ip-2019-04-8054 – wianlab (western istrian anticline as an ideal natural laboratory for the study of the regional unconformities in carbonate rocks; pi professor goran durn). references abedini, a., azizi, m.r. & calagari, a.a. (2019): ree mobility and tetrad effects in bauxites: an example from the kanisheeteh deposit, nw iran.– acta geodynamica et geomaterialia, 16/1, 11–26. doi: 10.13168/ agg.2019.0002 abedini, a. & calagari, a.a. (2014): ree geochemical characteristics of titanium-rich bauxites: the permian kanigorgeh horizon, nw iran.– turkish journal of earth sciences, 23, 513–532. doi: 10.3906/yer-1404-11 abedini, a., calagari, a.a. & azizi, m.r. (2018). the tetrad-effect in rare earth elements distribution patterns of titanium-rich bauxites: evidence from the kanigorgeh deposit, nw iran.– journal of geochemical exploration, 186, 129–142. doi: 0.1016/j.gexplo.2017.12.007 abedini, a., mongelli, g., khosravi, m. & sinisi, r. (2020): geochemistry and secular trends in the middle–late permian karst bauxite deposits, northwestern iran.– ore geology reviews, 124, 1–20. doi: 10.1016/j.oregeorev.2020.103660 aleva, g.j.j. (1994): laterites: concepts, geology, morphology and chemistry.– in: international soil reference and information center (isric) the corlat handbook, corlat technical, isric, wageningen, 169 p. algeo, t.j., luo, g.m., song, h.y., lyons, t.w. & canfield, d.e. (2015): reconstruction of secular variation in seawater sulfate concentrations.– biogeosciences, 12/7, 2131–2151. doi: 10.5194/bg-12-2131-2015 bárdossy, g. (1982): karst bauxites: bauxite deposits on carbonate rocks.– elsevier scientific publishing company, amsterdam–oxford– new york, 441 p. barrie, c.d., boyce, a.j., boyle, a.p., williams, p.j., blake, k., ogawara, t., akai, j. & prior, d.j. (2009): growth controls in colloform pyrite.– american mineralogist, 94/4, 415‒429. doi: 10.2138/ am.2009.3053 bau, m., möller, p. & dulski, p. (1997): yttrium and lanthanides in eastern mediterranean seawater and their fractionation during redox-cycling.– marine chemistry, 56/1–2, 123‒131. doi: 10.1016/s03044203(96)00091-6 bergant, s., matičec, d., fuček, l., palenik, d., korbar, t., šparica, m., koch, g., galović, i. & prtoljan, b. (2020): basic geological map of the republic of croatia scale 1:50.000, sheet: rovinj 2.– department of geology, croatian geological survey, zagreb. berner, r.a. (1970): sedimentary pyrite formation.– american journal of science, 28, 1‒23. doi: 10.2475/ajs.268.1.1 brlek, m., gaynor, s.p., mongelli, g., bauluz, b., sinisi, r., brčić, v., peytcheva, i., et al. (2021): karst bauxite formation during miocene climatic optimum (central dalmatia, croatia): mineralogical, compositional and geochronological perspectives.– international journal of earth sciences, 110/531. doi: 10.1007/s00531-021-02091-z calagari, a.a. & abedini, a. (2007): geochemical investigations on permo-triassic bauxite horizon at kanisheeteh, east of bukan, west-azarbaidjan, iran.– journal of geochemical exploration, 94/1, 1–18. doi: 10.1016/j.gexplo.2007.04.003 g eo lo gi a c ro at ic a 176 geologia croatica 77/2 canfield, d.e., raiswell, r., westrich, j.t., reaves, c.m. & berner, r.a. (1986): the use of chromium reduction in the analysis of reduced inorganic sulfur in sediments and shales.– chemical geology, 54/1, 149‒155. doi: 10.1016/0009-2541(86)90078-1 cao, x., chen, y., wang, x., & deng, x. (2001): effects of redox potential and ph value on the release of rare earth elements from soil.– chemosphere, 44/4, 655–661. doi: 10.1016/s0045-6535(00)00492-6 carannante, g., mindszenty, a., neumann, a.c., rasmussen, k.a., simone, l. & tóth, k. (1994): inland blue-hole-type ponds in the mesozoic–tertiary karst filling sequences.– in: ias 15th regional meeting, abstracts. ischia, 102–103. carannante, g., d'argenio, b., mindszenty, a., ruberti, d., & simone, l. (1994). cretaceous–miocene shallow water carbonate sequences. regional unconformities and facies patterns.– in: carannante, g & tonielli, r. (eds.): field trip guide book: 15th regional ias meeting. de frede, napoli, 25–60. cavalazzi, b., barbieri, r., cady, s.l., george, a.d., gennaro, s., westall, f., lui, a., et al. (2012): iron-framboids in the hydrocarbon-related middle devonian hollard mound of the anti-atlas mountain range in morocco: evidence of potential microbial biosignatures.– sedimentary geology, 263/264,183‒264. doi: 10.1016/j.sedgeo.2011.09.007 chambers, l.a. & trudinger, p.a. (1979): microbiological fractionation of stable sulfur isotopes: a review and critique.– geomicrobiology journal, 1/3, 249‒293. doi: 10.1080/01490457909377735 chen, j., wang, q., zhang, q., carranza, e.j.m. & wang, j. (2018): mineralogical and geochemical investigations on the iron-rich gibbsitic bauxite in yongjiang basin, sw china.– journal of geochemical exploration, 188. doi: 10.1016/j.gexplo.2018.02.007 chen, p., liu, b., wang, t., zhou, l., wang, y., sun, g., hou, k., et al. (2022): genesis of the danping bauxite deposit in northern guizhou, southwest china: constraints from in-situ elemental and sulfur isotope analyses in pyrite.– ore geology reviews, 148. doi: 10.1016/j.oregeorev.2022.105056 chen, t. (1978): colloform and framboidal pyrite from the caribou deposit, new brunswick.– canadian mineral., 16/1, 9‒15. d’ambrosi, c. (1926): rapporti fra morfologia e trasgresioni nel cretaceo e nel terziario dell’istria.– atti della accademia scientifica veneto– trentino–istriana, 16/13, 90–98. d’argenio, b. & mindszenty, a. (1995): bauxites and related paleokarst: tectonic and climatic event markers at regional unconformities.– eclogae geologicae helvetiae, 88/3, 453‒499. davranche, m., grybos, m., gruau, g., pédrot, m., dia, a. & marsac, r. (2011): rare earth element patterns: a tool for identifying trace metal sources during wetland soil reduction.– chemical geology, 284/1–2, 127‒137. doi: 10.1016/j.chemgeo.2011.02.014 diakonov, i.i., ragnarsdottir, k.v. & tagirov, b.r. (1998): standard thermodynamic properties and heat capacity equations of rare earth hydroxides: ii. ce(iii)-, pr-, sm-, eu(iii)-, gd-, tb-, dy-, ho-, er-, tm-, yb-, and y-hydroxides. comparison of thermochemical and solubility data.– chemical geology, 151/1–4, 327‒347. doi: 10.1016/s00092541(98)00088-6 doebelin, n. & kleeberg, r. (2015): profex: a graphical user interface for the rietveld refinement program bgmn.– journal of applied crystallography, 48, 1573‒1580. doi: 10.1107/s1600576715014685 dragović, d. (1989): the red and white karstic bauxites of montenegro (yugoslavia.).– travaux, 19/22, 249–257. durn, g., mindszenty, a., tišljar, j. & mileusnić, m. (2006): clay mineralogy of bauxites and palaeosols in istria formed during regional subaerial exposures of the adriatic carbonate platform.– in: vlahović, i., tibljaš, d. & durn, g. (eds.): 3rd mid-european clay conference: field trip guidebook, university of zagreb, faculty of science and faculty of mining, geology and petroleum engineering, zagreb, croatia, 3–30. durn, g., ottner, f., tišljar, j., mindszenty, a. & barudžija, u. (2003): regional subaerial unconformities in shallow-marine carbonate sequences of istria: sedimentology, mineralogy, geochemistry and micromorphology of associated bauxites, palaeosols and pedo-sedimentary complexes.– in vlahović, i. & tišljar, j. (eds.): field trip guidebook: evolution of depositional environments from the palaeozoic to the quaternary in the karst dinarides and the pannonian basin. 22nd ias meeting of sedimentology, institute of geology zagreb, zagreb, 209–255. durn, g., perković, i., mileusnić, m., vlahović, i., ružičić, s., matešić, d., cvetko tešović, b., et al. (2023): red istria: western istrian anticline as an ideal natural laboratory for the study of the regional unconformities in carbonate rocks.– in: fio firi, k. & čobić, a. (eds.): field trip a2, excursion guide-book, 7th croatian geological congress with international participation, hrvatski geološki institut, zagreb, 33–58. economou-eliopoulos, m., kontou, m. & megremi, i. (2022): biogeochemical redox processes controlling the element cycling: insights from karst-type bauxite, greece.– minerals, 12/4:446. doi: 10.3390/ min12040446 ellahi, s.s., taghipour, b. & nejadhadad, m. (2017): the role of organic matter in the formation of high-grade al deposits of the dopolan karst type bauxite, iran: mineralogy, geochemistry, and sulfur isotope data.– minerals, 7/6. doi: 10.3390/min7060097 ellahi, s.s., taghipour, b., zarasvandi, a., bird, m.i. & d somarin, a.k. (2015): mineralogy, geochemistry and stable isotope studies of the dopolan bauxite deposit, zagros mountain, iran.– minerals, 6/1. doi: 10.3390/min6010011 feng, j. l. (2010): behaviour of rare earth elements and yttrium in ferromanganese concretions, gibbsite spots, and the surrounding terra rossa over dolomite during chemical weathering.– chemical geology, 271/3–4, 112–132. doi: 10.1016/j.chemgeo.2010.01.003 ferreira da silva, e., bobos, i., xavier matos, j., patinha, c., reis, a.p. & cardoso fonseca, e. (2009): mineralogy and geochemistry of trace metals and ree in volcanic massive sulfide host rocks, stream sediments, stream waters and acid mine drainage from the lousal mine area (iberian pyrite belt, portugal).– applied geochemistry, 24/3, 383‒401. doi: 10.1016/j.apgeochem.2008.12.001 flügel, e. (2004): microfacies of carbonate rocks, microfacies of carbonate rocks.– springer verlag, berlin, 976 p. doi: 10.1007/978-3-66208726-8 gamaletsos, p.n., godelitsas, a., kasama, t., church, n.s., douvalis, a.p., göttlicher, j., steininger, r., et al. (2017): nano-mineralogy and geochemistry of high-grade diasporic karst-type bauxite from parnassos–ghiona mines, greece.– ore geology reviews, 84. doi: 10.1016/j.oregeorev.2016.11.009 graulis, s., chateigner, d., downs, r.t., yokochi, a.f.t., quirós, m., lutterotti, l., manakova, e., et al. (2009): crystallography open database – an open-access collection of crystal structures.– journal of applied crystallography, 42/4. doi: 10.1107/ s0021889809016690 grybos, m., davranche, m., gruau, g. & petitjean, p. (2007): is trace metal release in wetland soils controlled by organic matter mobility or fe-oxyhydroxides reduction?– journal of colloid and interface science, 314/2, 490‒501. doi: 10.1016/j.jcis.2007.04.062 hámor, t. (1994): the occurrence and morphology of sedimentary pyrite.– bulletin of the hungarian geological society, 37/1–2, 153–181. he, j., yang, l., shi, x., zhao, s., cao, l., pan, s., wu, f., et al. (2022): genetic mechanism of pyrite in the shale of the longmaxi formation and its influence on the pore structure: a case study of the changning area, south sichuan basin of sw china.– frontiers in earth science, 10. doi: 10.3389/feart.2022.919923 van hinsbergen, d.j.j., torsvik, t.h., schmid, s.m., maţenco, l.c., maffione, m., vissers, r.l.m., gürer, d., et al. (2020): orogenic architecture of the mediterranean region and kinematic reconstruction of its tectonic evolution since the triassic.– gondwana research, 81, 79–229. doi. 10.1016/j.gr.2019.07.009 g eologia c roatica 177perković et al.: tracing the evolution of the world's first mined bauxite from palaeotopography to pyritization: insights from minjera deposits ... hough, g., swapp, s., frost, c. & fayek, m. (2019): sulfur isotopes in biogenically and abiogenically derived uranium roll-front deposits.– economic geology, 114/2, doi: 10.5382/econgeo.2019.4634 huang, f., gao, s., chen, l., su, l., li, y., meng, l., liu, k., et al. (2020): micro-texture and in situ sulfur isotope of pyrite from the baiyunpu pb–zn deposit in central hunan, south china: implications for the growth mechanism of colloform pyrite aggregates.– journal of asian earth sciences, 193. doi: 10.1016/j.jseaes.2020.104302 jež, j., otoničar, b. (2018): late cretaceous geodynamics of the northern sector of the adriatic carbonate platform (western slovenia).– newsletters on stratigraphy, 51/4, 381–410. ji, h., wang, s., ouyang, z., zhang, s., sun, c., liu, x. & zhou, d. (2004): geochemistry of red residua underlying dolomites in karst terrains of yunnan–guizhou plateau ii. the mobility of rare earth elements during weathering.– chemical geology, 203/1–2, 1‒27. doi: 10.1016/j.chemgeo.2003.08.012 kawabe, i., kitahara, y. & naito, k. (1991): non-chondritic yttrium/ holmium ratio and lanthanide tetrad effect observed in pre-cenozoic limestones.– geochemical journal, 25/1, 31–44. doi:10.2343/geochemj.25.31 kelemen, p., dunkl, i., csillag, g., mindszenty, a., von eynatten, h. & józsa, s. (2017): tracing multiple resedimentation on an isolated karstified plateau: the bauxite-bearing miocene red clay of the southern bakony mountains, hungary.– sedimentary geology, 358/1, 84‒96. doi: 10.1016/j.sedgeo.2017.07.005 kelemen, p., dunkl, i., csillag, g., mindszenty, a., józsa, s., fodor, l. & von eynatten, h. (2023): origin, timing and paleogeographic implications of paleogene karst bauxites in the northern transdanubian range, hungary.– international journal of earth sciences, 112/1. doi: 10.1007/s00531-022-02249-3 laskou, m. & economou-eliopoulos, m. (2007): the role of microorganisms on the mineralogical and geochemical characteristics of the parnassos–ghiona bauxite deposits, greece.– journal of geochemical exploration, 93/2, 67‒77. doi: 10.1016/j.gexplo.2006.08.014 laskou, m. & economou-eliopoulos, m. (2013): bio-mineralization and potential biogeochemical processes in bauxite deposits: genetic and ore quality significance.– mineralogy and petrology, 107/4, 471‒486. doi: 10.1007/s00710-012-0257-z laveuf, c., cornu, s. & juillot, f. (2008): rare earth elements as tracers of pedogenetic processes.– comptes rendus – geoscience, 340/8, 523–532. doi: 10.1016/j.crte.2008.07.001 liu, x., wang, q., feng, y., li, z. & cai, s. (2013). genesis of the guangou karstic bauxite deposit in western henan, china.– ore geology reviews, 55/c, 162‒175. doi: 10.1016/j.oregeorev.2013.06.002 maksimović, z., mindszenty, a. & panto, g. (1991): contribution to the geochemistry of hungarian karst bauxites and the allochthony/ autochthony problem.– acta geologica hungarica, 34/4, 317‒334. maksimović, z. & pantó, g. (1991): contribution to the geochemistry of the rare earth elements in the karst-bauxite deposits of yugoslavia and greece.– geoderma, 51/1–4, 93–109. doi: 10.1016/0016-7061(91)90067-4 mameli, p., mongelli, g., oggiano, g. & dinelli, e. (2007): geological, geochemical and mineralogical features of some bauxite deposits from nurra (western sardinia, italy) insights on conditions of formation and parental affinity.– international journal of earth sciences, 96/5, 887–902. doi:10.1007/s00531-006-0142-2 matičec, d., vlahović, i., velić, i. & tišljar, j. (1996): eocene limestones overlying lower cretaceous deposits of western istria (croatia): did some parts of present istria form land during the cretaceous.– geologia croatica, 49/1, 117‒127. doi: 10.4154/gc.1994.46 mederski, s., pršek, j., majzlan, j., kiefer, s., dimitrova, d., milovský, r., koch, c.b., et al. (2022): geochemistry and textural evolution of as–tl-sb-hg-rich pyrite from a sediment-hosted as-sb-tlpb ± hg ± au mineralization in janjevo, kosovo.– ore geology reviews, 151, doi: 10.1016/j.oregeorev.2022.105221 mehra, o.p. & jackson, m.l. (1960), iron oxide removal from soils and clays by a dithionite–citrate system buffered with sodium bicarbonate.– in: clays and clay minerals: proceedings of the seventh national conference, clays and clay minerals. mo, h., yang, r., luo, c., li, x., ji, y., yang, g., zhou, x., et al. (2023): effect of karst geomorphology on the sedimentary mineralization and geochemical distribution of bauxite: an example from the xiaoyuan area in qingzhen, guizhou province.– minerals, 13/8. doi: 10.3390/ min13081013 mondillo, n., di nuzzo, m., kalaitzidis, s., boni, m., santoro, l. & balassone, g. (2022): petrographic and geochemical features of the b3 bauxite horizon (cenomanian‒turonian) in the parnassos– ghiona area: a contribution towards the genesis of the greek karst bauxites.– ore geology reviews, 143. doi: 10.1016/j.oregeorev.2022. 104759 mongelli, g. (1997): ce-anomalies in the textural components of upper cretaceous karst bauxites from the apulian carbonate platform (southern italy).– chemical geology, 140/1–2, 69‒79. doi: 10.1016/s00092541(97)00042-9 mongelli, g., boni, m., buccione, r. & sinisi, r. (2014): geochemistry of the apulian karst bauxites (southern italy): chemical fractionation and parental affinities.– ore geology reviews, 63, 9‒21. doi: 10.1016/j.oregeorev.2014.04.012 mongelli, g., boni, m., oggiano, g., mameli, p., sinisi, r., buccione, r. & mondillo, n. (2017): critical metals distribution in tethyan karst bauxite: the cretaceous italian ores.– ore geology reviews, 86, 526‒536. doi: 10.1016/j.oregeorev.2017.03.017 mongelli, g., mameli, p., sinisi, r., buccione, r. & oggiano, g. (2021): rees and other critical raw materials in cretaceous mediterranean-type bauxite: the case of the sardinian ore (italy).– ore geology reviews, 139/b. doi: 10.1016/j.oregeorev.2021.104559 nia, r. (1968): geologische, petrographische, geochemische untersuchungen zum problem der boehmit-diaspor-genese in griechischen oberkreide-bauxiten der parnass-kiona-zone.– phd thesis, university of hamburg, 1–133. otoničar, b. (2006): upper cretaceous to palaeogene forebulge unconformity associated with foreland basin evolution (kras, matarsko polje and istria, southwestern slovenia and northwestern croatia).– acta carsologica, 36/1, 101–120. doi.org/10.3986/ac.v36i.213 olías, m., cánovas, c.r., basallote, m.d. & lozano, a. (2018): geochemical behaviour of rare earth elements (ree) along a river reach receiving inputs of acid mine drainage–. chemical geology, 493, 468‒477. doi: 10.1016/j.chemgeo.2018.06.029 öztürk, h., hein, j.r. & hanilçi, n. (2002): genesis of the doǧankuzu and mortaş bauxite deposits, taurides, turkey: separation of al, fe, and mn and implications for passive margin metallogeny.– economic geology, 97/5, 1063‒1077. doi: 10.2113/gsecongeo.97.5.1063 pasquier, v., fike, d.a. & halevy, i. (2021): sedimentary pyrite sulfur isotopes track the local dynamics of the peruvian oxygen minimum zone.– nature communications, 12/1:440312/1. doi: 10.1038/s41467-02124753-x pourret, o., davranche, m., gruau, g. & dia, a. (2007): rare earth elements complexation with humic acid.– chemical geology, 243/1–2, 128–141. doi: 10.1016/j.chemgeo.2007.05.018 pourret, o., davranche, m., gruau, g. & dia, a. (2008): new insights into cerium anomalies in organic-rich alkaline waters.– chemical geology, 251/1–4, 120‒127. doi: 10.1016/j.chemgeo.2008.03.002 radusinović, s. & papadopoulos, a. (2021): the potential for ree and associated critical metals in karstic bauxites and bauxite residue of montenegro.– minerals, mdpi, 11/9, 975. doi: 10.3390/min11090975 raiswell, r. (1982): pyrite texture, isotopic composition and the availability of iron.– american journal of science, 282/8, 1244‒1263. doi: 10.2475/ajs.282.8.1244 rasmussen, k., neumann, a.c.n. (1988): holocene overprint of pleistocene paleokarst: bight of abaco, bahamas.– in: james, n.p., choquette p.w. (eds.): paleokarst. springer-verlag, 132–148. g eo lo gi a c ro at ic a 178 geologia croatica 77/2 roedder, e. (1968): the non-colloidal origin of ‘colloform’ textures in sphalerite ores.– economic geology, 63/5, 451‒471. doi: 10.2113/gsecongeo.63.5.451 schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m., et al. (2008): the alpine–carpathian–dinaridic orogenic system: correlation and evolution of tectonic units.– swiss journal of geosciences, 101/1, 139–183. doi: 10.1007/s00015-008-1247-3 schmid, s.m., fügenschuh, b., kounov, a., maţenco, l., nievergelt, p., oberhänsli, r., pleuger, j., et al. (2020): tectonic units of the alpine collision zone between eastern alps and western turkey.– gondwana research, 308–374. doi: 10.1016/j.gr.2019.07.005 shaheen, s.m., alessi, d.s., tack, f.m.g., ok, y.s., kim, k.h., gustafsson, j.p., sparks, d.l., et al. (2019). redox chemistry of vanadium in soils and sediments: interactions with colloidal materials, mobilization, speciation, and relevant environmental implications – a review.– advances in colloid and interface science, 265, 1–13. doi: 10.1016/j.cis.2019.01.002 šinkovec, b., sakač, k. & durn, g. (1994): pyritized bauxites from minjera, istria, croatia.– natura croatica, 3/1, 41–65. tabelin, c.b., igarashi, t., villacorte-tabelin, m., park, i., opiso, e.m., ito, m. & hiroyoshi, n. (2018): arsenic, selenium, boron, lead, cadmium, copper, and zinc in naturally contaminated rocks: a review of their sources, modes of enrichment, mechanisms of release, and mitigation strategies.– science of the total environment, 645/7, 1522‒1553. doi: 10.1016/j.scitotenv.2018.07.103 tang, j. & johannesson, k.h. (2003): speciation of rare earth elements in natural terrestrial waters: assessing the role of dissolved organic matter from the modeling approach.– geochimica et cosmochimica acta, 67/13, 2321–2339. doi: 10.1016/s0016-7037(02)01413-8 taylor, s.r. & mclennan, s.m. (1985): the continental crust: its composition and evolution, the continental crust: its composition and evolution. an examination of the geochemical record preserved in sedimentary rocks.– blackwell science, oxford, 312 p. tomašić, n., čobić, a., bedeković, m., miko, s., ilijanić, n., gizdavec, n. & matošević, m. (2021): rare earth elements enrichment in the upper eocene tošići‐dujići bauxite deposit, croatia, and relation to ree mineralogy, parent material and weathering pattern.– minerals, 11/1:1260. doi: 10.3390/min11111260 velić, i., matičec, d., tišljar, j. & vlahović, i. (1995): opći prikaz geološke građe istre (a review of the geology of istria).– in: vlahović, i. & velić, i. (eds.): 1st croatian geological congress, excursion guidebook. croatian geological survey, zagreb, 5–30. vind, j., malfliet, a., blanpain, b., tsakiridis, p.e., tkaczyk, a.h., vassiliadou, v. & panias, d. (2018): rare earth element phases in bauxite residue.– minerals, 8/2:77. doi: 10.3390/min8020077 vlahović, i., tišljar, j. & velić, i. (1994): influence of synsedimentary tectonics and eustatic changes on deposition of the cenomanian platform carbonates in istria (western croatia).– géologie méditerranéenne, 21/3‒4, 189‒193. doi: 10.3406/geolm.1994.1561 vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeography, palaeoclimatology, palaeoecology, 220/3–4, 333–360. doi: 10.1016/j.palaeo.2005.01.011 wang, x., jiao, y., du, y., ling, w., wu, l., cui, t., zhou, q., et al. (2013): ree mobility and ce anomaly in bauxite deposit of wzd area, northern guizhou, china.– journal of geochemical exploration, 133, 103–117. doi: 10.1016/j.gexplo.2013.08.009 wang, b., lei, h. & huang, f. (2022): impacts of sulfate-driven anaerobic oxidation of methane on the morphology, sulfur isotope, and trace element content of authigenic pyrite in marine sediments of the northern south china sea.– marine and petroleum geology, 139. doi: 10.1016/j. marpetgeo.2022.105578 wanty, r.b. & goldhaber, m.b. (1992): thermodynamics and kinetics of reactions involving vanadium in natural systems: accumulation of vanadium in sedimentary rocks.– geochimica et cosmochimica acta, 56/4, 1471–1483. doi: 10.1016/0016-7037(92)90217-7 wignall, p.b. & newton, r. (1998): pyrite framboid diameter as a measure of oxygen deficiency in ancient mudrocks.– american journal of science, 298/7, 537‒552. doi: 10.2475/ajs.29 wilkin, r.t., barnes, h.l. (1996): pyrite formation by reactions of iron monosulfides with dissolved inorganic and organic sulfur species.– geochimica et cosmochimicha.acta, 60/21, 4167–4179. doi: 10.1016/ s0016-7037(97)81466-4 williams, j.r. (2014): karst-associated bauxite deposits of parnassos– ghiona, central greece: ore genesis and structural evolution.– ph.d. thesis, university of brighton, 311 p. xiao, j., li, y., yang, h., xu, j. & huang, m. (2021): geochemistry of the yudong bauxite deposit, south-eastern guizhou, china: implications for conditions of formation and parental affinity.– journal of geochemical exploration, 220. doi: 10.1016/j.gexplo.2020.106676 yang, l., wang, q., zhang, q., carranza, e.j.m., liu, h., liu, x. & deng, j. (2017): interaction between karst terrain and bauxites: evidence from quaternary orebody distribution in guangxi, sw china.– scientific reports, 7/1. doi: 10.1038/s41598-017-12181-1 yang, s., wang, q., deng, j., wang, y., kang, w., liu, x. & li, z. (2019): genesis of karst bauxite-bearing sequences in baofeng, henan (china), and the distribution of critical metals.– ore geology reviews, 115. doi: 10.1016/j.oregeorev.2019.103161 yue, l., jiao, y., wu, l., rong, h., fayek, m. & xie, h. (2020): evolution and origins of pyrite in sandstone-type uranium deposits, northern ordos basin, north-central china, based on micromorphological and compositional analysis.– ore geology reviews, 118. doi: 10.1016/j.oregeorev.2020.103334 yuste, a., bauluz, b. & mayayo, m.j. (2017): origin and geochemical evolution from ferrallitized clays to karst bauxite: an example from the lower cretaceous of ne spain.– ore geology reviews, 84/3, 67‒79. doi: 10.1016/j.oregeorev.2016.12.025 zarasvandi, a., carranza, e.j.m. & ellahi, s.s. (2012): geological, geochemical, and mineralogical characteristics of the mandan and deh-now bauxite deposits, zagros fold belt, iran.– ore geology reviews, 48, 125‒138. doi: 10.1016/j.oregeorev.2012.02.010 zhang, j.-y., wang, q., liu, x.-f., zhou, g.-f., xu, h.-p. & zhu, y.-g. (2022): provenance and ore-forming process of permian lithium-rich bauxite in central yunnan, sw china.– ore geology reviews, 145. doi: 10.1016/j.oregeorev.2022.104862 zhao, l., liu, x., wang, q., ma, x., liu, l., sun, x. & deng, j. (2023): genetic mechanism of super-large karst bauxite in the northern north china craton: constrained by diaspore in-situ compositional analysis and pyrite sulfur isotopic compositions.– chemical geology, 622. doi: 10.1016/j.chemgeo.2023.121388 zhou, w., han, g., liu, m., song, c. & li, x. (2020): geochemical distribution characteristics of rare earth elements in different soil profiles in mun river basin, northeast thailand.– sustainability, 12/2, 457. doi: 10.3390/su12020457 2020 | 73/2 | 85–94 | 5 figs. | 1 tab. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the studied upper jurassic outcrops are located to the north of the town of tiaret on the boundary of the southern tellian domain (fig. 1). the uppermost jurassic deposits are distributed in north africa along the southern margin of the former tethys ocean. in northwestern algeria, the oxfordian strata stretch over the tellian atlas and are named as the ammonitico rosso de frid and argiles rouges de kheneg (atrops & benest, 1994), in the oran and arzew mountains (northern tell) they are known as the upper oxfordian “grès chocolatés” and eventually as “l’ensemble détritique à ostracodes” in the tessala mountains (fenet, 1975). in the high plateaus oxfordian rocks have been either referred to the “argiles de saïda’’ in the tlemcenian domain (augier, 1967; elmi & benest, 1978; cherif et al., 2015, 2018; halamski & cherif, 2017), or as the “grès de sidi saâdoun” and “argiles de faïdja” (caratini, 1970; atrops & benest, 1981). the argiles rouges de kheneg formation is composed of red marly limestone in the lower part, thick sandstone in the middle, and red to green clay-limestone-sandstone intercalations in the upper part. the best exposures are located in the oued kheneg and aïn el hamra areas (fig. 1). they have been mapped and investigated since the late 19th century (e.g., welsch, 1890; polvèche, 1960; tchoumatchenco & khrischev, 1992). so far, these deposits had never been described from ichnological and sedimentology points of view. the present paper presents the first ichnologic and sedimentological study of the oxfordian deposits exposed at oued kheneg and aïn el hamra (north of tiaret). our contribution provides a list of ichnotaxa and a facies inventory that aid the interpretation of the depositional environment. 2. geographical and geological framework geographically, the study site belongs to the northern domain of algeria called ”alpine algeria”, which consists of three domains first record of trace fossils from the oxfordian argiles rouges de kheneg formation (tiaret, northwestern algeria) mourad belaid(1,2)*, amine cherif(1,3)*, olev vinn(4) and mohammed nadir naimi(1,3) 1 kasdi-merbah university, faculty of hydrocarbons, renewable energies, earth sciences and universe, department of earth sciences and universe, ghardaïa road, ouargla, 3000, algeria (*corresponding author) 2 kasdi-merbah university, laboratory of underground reservoirs: petroleum, gas and aquifers; (belaid.mourad@univ-ouargla.dz) 3 kasdi-merbah university, laboratory of geology of sahara, algeria; acherif11@gmail.com (amine cherif), mohammednadirnaimi@gmail.com (mohammed nadir naimi) 4 university of tartu, department of geology, , ravila 14a, 50411 tartu, estonia; (olev.vinn@ut.ee) doi: 10.4154/gc.2020.10 abstract three main facies associations fa-1 to fa-3 occur in the oxfordian argiles rouges de kheneg formation in northwestern algeria. they correspond respectively to the deeper part of a mixed siliciclastic-carbonate shelf, upper shoreface and offshore transition-lower offshore. the trace fossil association of the argiles rouges de kheneg formation contains fifteen ichnogenera and is moderately diverse for the upper jurassic. the formation contains diverse and abundant deep water or dominantly deep water trace fossils (i.e. belorhaphe, chondrites, helminthopsis, nereites, megagrapton). they indicate that a part of the formation was deposited in offshore transition to lower offshore environments. comprising young mountains formed during the alpine orogeny. these domains are, from north to south: (i) the tellian atlas (knappe domain, composed of sedimentary rocks ranging from the jurassic to miocene in age); (ii) the high plateaus (the foreland of the alpine range bearing a thin sedimentary cover of jurassic age). in the western part, there are a series of mountain ranges such as the saïda mountains and the frenda mountains; (iii) the saharan atlas (formed from an elongated trough pinched between the high plateaus and the saharan platform, infilled with a thick sedimentary sequence during the mesozoic times). from the palaeogeographic point of view, alpine algeria was a part of north-western africa during the mesozoic, and was characterized by the individualization of two different paleogeographic domains: the autochthonous intracontinental chains (the atlas s.s., frizon de lamotte et al,. 2008) and the rif range with the tellian-kabylian belt (maghrebides), composed of parautochthonous to allochthonous units (chalouan et al., 2008). the history of these domains is contemporary with the opening of the central atlantic and neo-tethys oceans (brede et al., 1992; gomez et al., 2000) during the late jurassic, on the southern shelf of western tethys (e.g. dercourt et al., 1993; berra & angiolini, 2014). however, the study area was likely to have bathyal water depths (tchoumatchenco & khrischev, 1992). the argiles rouges de kheneg formation contains the upper jurassic marine deposits outcropping in the southern tell atlas. these deposits are mostly of pelagic origin, with subordinate yet locally important detrital beds at the midupper oxfordian ‘’grès intercalaires’’. in the uppermost late oxfordian, intermittent siliciclastic deposits have been described as the argiles de saïda facies (subunit c-2 in this study) and interpreted as a result of intra-oxfordian tectonic movements (atrops & benest, 1981). in the middle oxfordian to late oxfordian, of the argiles de saïda formation in the saïda mountains and the frenda mountains, the depositional environment was characterized by shallow article history: manuscript received april 25, 2020 revised manuscript accepted june 30, 2020 available online june 29, 2020 keywords: oxfordian, kheneg, algeria, trace fossil, offshore mailto:belaid.mourad@univ-ouargla.dz mailto:acherif11@gmail.com mailto:olev.vinn@ut.ee g eo lo gi a c ro at ic a geologia croatica 73/286 water mixed carbonate-siliciclastic deposition, as evidenced by frequent tidal and tempestite structures (cherif et al., 2015, 2018; halamski & cherif, 2017). 3. facies characteristics and stratigraphy the argiles rouges de kheneg formation was defined by atrops & benest (1994), in order to accommodate a series of marine deposits above the middle oxfordian ammonitico rosso de frid formation and overlain by the kimmeridgian calcaires du bou rheddou formation. these deposits display a wide array of different lithologies, such as marly and nodular/pseudo-nodular limestones, and bioturbated sandstones. however, the formation can be subdivided into three informal units, based on their respective faunal and lithologic features (corresponding to the facies-type, namely f1-f4) (fig. 2). unit a (lowermost part of the formation – lower ammonitico rosso) this first unit is up to 25 m thick in the aïn el hamra area, and about 15 m thick in oued kheneg. it consists of the alternation of red claystone /marlstone interlayers (facies f1) 0.10 to 0.50 m thick (displaying planktonic foraminifers and ostracods) and red to green nodular limestone (facies f2), occurring in 0.20 to 3 m thick packages. both f1 and f2 commonly contain ammonites, echinoids, crinoids, bivalves and brachiopods. the microscopic scale of f2 (atrops & benest, 1984, 1986) shows skeletal and intraclast components with non-skeletal grains (ooids and pellets) forming wackestone and packstone-textured carbonates. the fossil allochems include echinoid debris, crinoid fragments, bivalves, and planktonic foraminifers. the ammonite communities indicate the stenocycloides subzone with gregoryceras fouquei (kilian) and the grossouvrei subzone with rare perisphinctes (dichotomoceras) bifurcatus (quenstedt) (atrops & benest, 1984). unit b (middle part of the formation – middle sandstone) this 5-15 m thick unit is easily distinguished from the upper part of the lower unit by the presence of a 0.20 to 1 m thick sandstone (facies f3), separated by centimetre thick red to green claystone interlayers. the middle sandstone unit shows a large variation in thickness from 15 m in the oued kheneg section to 5 m in the aïn el hamra section. the sandstone beds are yellow to brown when weathered, grey to greenish in fresh cuts. they show sharp erosive bases, pebble impressions, are channelized (fig. 3c), and show sole marks (flute-casts). the wave/current structures are usually represented by horizontal and sigmoidal bedding, thick sets of hummocky-cross stratification (hcs) and large wavy cross-bedding (fig. 3d). commonly, the beds show unidirectional, linguoid ripple-marks (fig. 3e) or mega-ripples (fig. 3f). at the top of this unit, the upper surface of the sandstone is highly bioturbated with large thalassinoides (fig. 5d). no body fossils have been recorded in this unit. figure 1. location map of the study area: (a and b) geographic location and satellite image of northwestern algeria; (c) satellite image of the study area (from google earth). g eologia c roatica belaid et al.: first record of trace fossils from the oxfordian argiles rouges de kheneg formation (tiaret, northwestern algeria) 87 unit c (uppermost part of the formation upper ammonitico rosso) this 40-45 m thick unit is divided into two subunits: 3.1. subunit c-1 (lower part of the unit) as the lower part of the formation, this 22-30 m subunit is mostly composed of alternations of interlayered decimetre thick red (rarely green) claystone/marlstone (f1) (0.60-1 m) and red, pink to green micritic limestone (f2) (0.10-0.20 m). the limestone is nodular to pseudo-nodular and bioturbated. the bioturbation is generally represented by filled burrows. in the lower part, the limestone beds are rich in ammonites, echinoids, crinoids, echinoderm debris, and brachiopods. broadly, the lithostratigraphic characteristics as well as the fossil content and the microscopic texture are similar to the lower unit. subunit c-2 (upper part of the unit) this subunit is 12 to 15 m thick, cropping at the upper part of the argiles rouges de kheneg formation (fig. 3g). it is mostly composed of green shales to red claystone (f1) and thin sandand siltstones (facies f4). f4 embrace fine-grained sandstones (subfacies f4-a) and millimetre to centimetre thick siltstone laminae (subfacies f4-b). the f4-a and f4-b are brown in colour, and are 0.02-0.15 m thick, show channelized and sharp erosive bases, contain septarian nodules (lower part of the succession). the beds display abundant flute-cast, groove-mark, load-cast, horizontal lamination, small scale hcs, unidirectional, wavy and linguoid ripple-marks (fig. 3h). the unit c was dated as the upper kimmerdgian (bimammatum zone, hypselum subzone to the planula zone, minutum subzone) on the basis of ammonites (atrops & benest, 1994). figure 2. stratigraphic succession, vertical distribution of trace fossils and facies association inventory of the upper oxfordian argiles rouges de kheneg formation (northwestern algeria). g eo lo gi a c ro at ic a geologia croatica 73/288 4. facies interpretation the table below summarizes the main facies (f1, f2, f3 and f4) with their principal lithological, sedimentological and ichnological features: 5. facies association and palaeoenvironment three facies associations have been distinguished, namely fa-1 to fa-3 5.1. facies association (fa-1): the deeper part of platform fa-1 comprises mudstone facies (f1) and limestone facies (f2), f1 includes red claystone (subfacies f1-a) and marlstone interlayers (subfacies f1-b). f1 and f2 are rhythmically interbedded and correspond to the ammonitico rosso facies of the lower unit and the subunit c-1 of the upper unit and locally to some parts of the subunit c-2. sediments of fa-1 were likely deposited in the deeper part of the carbonate shelf. 5.2. facies association (fa-2): upper shoreface fa-2 occurs exclusively in the middle unit and is composed of thick sandstone (f3), mostly thinning upward. it contains subordinate thin green claystone interlayers (f1-a). it may be attributed to the upper shoreface deposits and is the shallowest facies of the argiles rouges de kheneg formation. 5.3. facies association (fa-3): offshore transition-lower offshore the upper part of the argiles rouges de kheneg formation is composed of the facies association fa-3, which is made of interbedded fine-grained sandstones (f4-a), siltstones (f4-b) and claystone intervals (f1-a) (fig. 3g). the shallow-water and high-energy conditions are proven by several wave/current sedimentary structures, and the recorded trace fossils belong to the cruziana ichnofacies-nereites ichnofacies transition. this facies association represents deposition in offshore transition-lower offshore environments. 6. ichnology trace fossils are abundant and diverse in the subunit c-2 (uppermost part of the formation), but less frequent in the middle sandstone. fifteen ichnotaxa are recognized, presented in alphabetical order. belorhaphe zickzack heer, 1877 (fig.4a) this trace fossil is hypichnial zigzag and meanders in fine grained sandstones. most of the zigzags are with an apical angle table 1. distribution of the main facies, ichnogenera and depositional settings. facies-type general description fossils structures sedimentary process facies association and environment fa ci es f 1: m ud st on es subfacies f1-a claystone 0.10-1 m thick, massive, laminated or lumpy mudstone very finely flaky, dark red, grey to green color, ammonites, echinoids, crinoids, bivalves, brachiopods, foraminifers and ostracods. without wave/current or biogenic structures below storm-wave base f1a: suspension sedimentation at f1b: chimic, biochimic decantation of limestone process and fine argillaceous fraction input fa1= f1 + f2 (deeper part of carbonate shelf) subfacies f1-b marlstone facies f2: limestone nodular and pseudonodular, red, pink, green, 0.05-0.30m tick ammonites, echinoids, crinoids, bivalves, brachiopods, foraminifers and ostracods. chondrites isp., thalassinoides below storm wave-base, sedimentation speed, from decreased sediment input or secondarily increased winnowing by shelf currents. facies f3: thick sandstone thick beds, thinning upward. 0.20-1 m, yellow to brown, channelized, sharp erosive bases azoic thalassinoides isp., horizontal and sigmoidal bedding, hcs ripple-marks and mega-ripples, sole marks, pebble impressions deposition above storm-wave base fa2= f1 + f3 (upper shoreface) fa ci es f 4: th in sa nd a nd si lts to ne . su bf ac ie s f 4a: sa nd st on es brown to yellow, 0.02-0.15 m thick, channelized, sharp erosive bases azoic septarian nodules, flute-cast, groove-mark and load-cast horizontal lamination, hcs, wavy and ripple-marks. sandstones: above storm-wave base (offshore-transition) siltstones: post-storm deposits fa3= f1+ f4 (f1a) (offshore transition –lower offshore) belorhaphe zickzack, cf. bergaueria isp., helminthopsis isp., megagrapton irregulare, m. submontanum nereites isp., nereites irregularis, ophiomorpha isp., ophiomorpha rudis, o. annulata, palaeophycus isp., planolites isp., protovirgularia isp., thalassinoides isp. su bf ac ie s f 4b: si lts to ne s g eologia c roatica belaid et al.: first record of trace fossils from the oxfordian argiles rouges de kheneg formation (tiaret, northwestern algeria) 89 of 45°, 3 mm wide and 3-4 mm high. belorhaphe zickzack is a typical graphoglyptid burrow (seilacher, 1977) and occurs in clastic sediments of the deep sea (uchman, 1998; demircan & uchman, 2017). cf. bergaueria isp. (fig. 4b) this trace is a hypichnion perpendicular to the stratification plane. it occurs mainly in the upper part of the second and third units. bergaueria is a cylindrical structure, with an apical depression. it is considered as a resting or dwelling trace, produced by suspension feeders (fürsich, 1975; pemberton et al., 1988) and reported from shallow to deeper marine environments (crimes & anderson, 1985; uchman, 1998; cherif et al, 2015). chondrites isp. (fig. 4c) this trace is preserved as full relief, composed of a branching dendritic burrow network, mostly horizontal to the bedding. the burrows are from 0.5 to 1 mm wide, less than 30 mm long. chondrites is frequent in the bioturbated limestone of the lower and upper ammonitico rosso facies. it is considered as a fodinichnion (richter, 1927) of marine annelids (simpson, 1956), figure 3. some sedimentary features of the argiles rouges de kheneg formation. except the figures a, b, d, all the illustrations are from the aïn el hamra section: (a) ammonitico rosso (facies f2 from the uppermost part of the formation, the oued kheneg section), (b) detail of a, showing nodular red limestone, (c) lower bedding surface with pebble impression (middle part of the formation), (d) hummocky-cross stratification (hcs) (middle part of the formation, the oued kheneg section), (e) ripple-marks (middle part of the formation), (f) mega-ripples (red line) (middle part of the formation, the oued kheneg section), (g) interbedded claystone (f1-a) and thin sandstones (f4-a)/siltstone laminae (f4-b), (h) small scale hcs (subunit c2, upper part of the formation). g eo lo gi a c ro at ic a geologia croatica 73/290 and is classified as a chemichnion (bromley, 1996). generally, chondrites is reported from offshore (cherif et al, 2015, 2018) to deep-sea deposits or in deep tier (bromley, 1990), often considered to be an indicator of anoxia in sediments (bromley & ekdale 1984) helminthopsis isp. (fig. 4d) this trace is a hypichnial meandering ridge 0.2 to 2 mm wide and 100 mm long. it is attributed to polychaete worms (książkiewicz, 1977); mostly reported from deeper facies (chamberlain; 1971; wetzel et al., 2007). megagrapton irregulare książkiewicz, 1968 (fig. 4e) this trace fossil is preserved as a system of hypichnial, winding branched semi-cylindrical ridges forming an irregular net. the ridges are 1-2 mm wide, the branching points are 30-150 mm apart. m. irregulare has been observed in deposits of a wide spectrum of environments (buatois et al., 2017), but is considered to be typical of turbiditic deposits (książkiewicz, 1977; uchman, 1998). megagrapton submontanum azpeitia moros, 1933 (fig. 4f) these are hypichnial, winding branched ridges forming net with meshes bordered by strings, which are 1.0–1.7 mm wide and about four meshes are preserved. the maximum width of the mesh is 30 and 50 mm. m. submontanum occurs exclusively in deep water, mainly in flysch deposits (uchman, 1998). nereites isp. (fig. 5a) this is a set of hypichnial horizontal, meandering ribbons, 2.0-5.0 mm wide, bounded by an even zone which is 1-2 mm wide. nereites irregularis schafhäutl, 1851 (fig. 5b) this trace is preserved as an epichnial meandering burrow, made of a shallow furrow, 4-5 mm wide. nereites are locomotion traces of annelid worms (seilacher, 2007), commonly occurring in deep-sea deposits. it is composed of a median faecal string and bounding zones, which indicate sediment reworking (uchman, 1995). figure 4. trace fossils from the subunit c-2, upper part of the argiles rouges de kheneg formation: except for figures a and d, all the traces are from the oued kheneg section. (a) belorhaphe zickzack (bel) (the aïn el hamra section); (b) cf. bergaueria; (c) chondrites isp. (arrows) in nodular red limestone; (d) helminthopsis and unknown trace (ut) (the aïn el hamra section); (e) megagrapton irregulare; (f), megagrapton submontanum. g eologia c roatica belaid et al.: first record of trace fossils from the oxfordian argiles rouges de kheneg formation (tiaret, northwestern algeria) 91 ophiomorpha isp. (fig. 5c) this consists of a horizontal, cylindrical burrow 5 to 10 mm wide, and at a least of 70 mm long, covered by irregular pellets and co-occurs with planolites. cf. ophiomorpha annulata książkiewicz, 1977 (fig. 5d) occurs as a straight to slightly curved, horizontal tunnel, preserved in epirelief, on the sandstone bed, 2.5-8 mm in diameter, and about 250 mm long. o. annulata maybe smooth or showing arranged granules as a meniscate shape. ophiomorpha rudis książkiewicz, 1977 (fig. 5d) it co-occurs with palaeophycus and planolites as simple cylindrical burrows, straight or slightly curved, horizontal to bedding plane. this trace is 2.5–5 mm wide on average and 300 mm long, showing scratches or small to strong nodular external surfaces. ophiomorpha is produced by shrimp-like crustaceans, living in burrows made in high-energy coastal marine sand environments (frey et al., 1978), but it has also been reported from deep-sea deposits (kerrn & warme, 1974; uchman, 1995; uchman, 2009). palaeophycus isp. (fig. 5c-d and e) slightly sinusoidal horizontal and unbranched cylindrical burrows, 5 to 10 mm in diameter, a few centimetres to 150-200 mm-long; studied specimens are preserved as positive/negative epior hyporeliefs. this trace characterizes mainly the upper part figure 5. following on from figure. 4: except for figures b and g, all the traces are from the oued kheneg section, with (a) nereites isp.; (b) nereites irregularis (the aïn el hamra section), (c) ophiomorpha isp. (oph), planolites isp. (pla), (d) cf ophiomorpha annulta (opha) and ophiomorpha rudis (ophr), palaeophycus isp. (pal) and planolites isp. (pla), (e) palaeophycus isp. (f) protovirgularia isp. (pro) and another set of small to very small burrows (arrows) in the sole of fine grained saindstone, (g) large size thalassinoides isp. (middle sandstone unit, the aïn el hamra section), (h) thalassinoides isp. (th) and planolites isp. (pla) on the top of fine grained sandstone. g eo lo gi a c ro at ic a geologia croatica 73/292 of the third unit. palaeophycus is an extremely eurybathic faciescrossing trace, interpreted as a mostly dwelling burrow of suspension feeding or predatory worms (pemberton & frey, 1982). planolites isp. (fig. 5c-d and h) a straight, gently curved cylindrical burrow, preserved mostly as hypichnial ridges which are 2-4 mm wide and about 8.0 mm long. they are found solitarily or in association with ophiomorpha, palaeophucys and thalassinoides. planolites is attributed to vermiform deposit-feeders (pemberton & frey, 1982; uchman, 1995) and considered as facies-crossing from distal platforms (dam, 1990; cherif et al, 2015) to deepsea deposits (demircan, 2008). protovirgularia isp. (fig. 5f) protovirgularia occurs as horizontal cylindrical straight trail preserved as epirelief, 2.5 mm in diameter, with regular to irregular chevron-shaped markings. this trace is commonly attributed to fodinichnia and cubichnia of molluscs such as bivalves and it has been documented in estuarine deposits and wave-influenced deposits (mangano & buatois, 2004; uchman & gazdzicki, 2006; cherif et al, 2015, 2018). thalassinoides isp. (fig. 5g-h) thalassinoides consists of horizontal, sub-cylindrical systems of irregular burrows, generally dichotomous, y-shaped branching. all specimens are preserved as full-relief structures. burrow diameter ranges from 4 to 50 mm, they are 50 to 250 mmlong. thalassinoides is a facies-crossing ichnogenus, representing deposit-feeding and dwelling activities of crustaceans (fürsich, 1973), reported from shallow-marine (schlirf, 2000, cherif et al, 2015, 2018) to deep-marine (uchman, 1995) environments. 7. discussion and conclusions three main facies associations (fa-1 to fa-3) occur in the oxfordian argiles rouges de kheneg formation in northwestern algeria. two facies (fa-2 and fa-3) associations characterize shelf environments from the shallowest (fa-2) to deeper ones (fa-3), while fa-1 could be interpreted as the deepest part of the shelf, attributed to the intra-oxfordian tectonic movements (benest & atrops, 1998; cherif et al., 2015). the transition from fa-1 (lower ammonitico rosso unit) to fa-2 (middle sandstone unit) have been interpreted as an intermittent sandstone discharge caused by tectonic instability. the passage from fa-1 to fa-3 was attributed to an important sw current provenance of clastic influx, infilling and reducing the bathymetry, namely the argiles de saïda facies (atrops & benest, 1984). such evolution is indicated by stratal colour variations and attributed to temporal changes in sediment composition (e.g., clastic vs. carbonate content, savrda, 2007). hence, the oxfordian argiles rouges de kheneg formation is characterized by a diverse trace fossil association (15 ichnotaxa), occurring in a wide range of marine environments (i.e. bergaueria, ophiomorpha, palaeophycus, planolites, thalassinoides). however, deep water traces or predominantly deep water traces (i.e. belorhaphe, chondrites, helminthopsis, nereites, megagrapton) are also diverse and abundant in the argiles rouges de kheneg formation, indicating that this part of the formation was deposited under deep water conditions. they are interpreted as the cruziana ichnofacies-nereites ichnofacies transition, and the absence of the typical turbiditic sequence excludes the really deep flysch deposits, whereas the frequent wavy/storm structures could correspond to the offshore transition-lower offshore environment. in well-oxygenated substrates, the ichnofossil component is characterized by high diversity assemblages that contain forms of large diameter up to several centimetres (savrda, 2007). the presence of infaunal communities and traces of their activities is dependent on bottom-water oxygenation. the less diverse bioturbation is related to lower oxygen concentrations (e.g., rhoads and morse, 1971; savrda et al., 1984). therefore, the occurrence of chondrites without the other trace fossils in the ammonitico rosso facies (f2) from the lower and upper part of argiles rouges de kheneg formation have been regarded as an indicator of the low oxygen concentrations in bottom waters (bromley & ekdale, 1984; savrda and bottjer, 1989; wignall, 1991), or dysoxic conditions representing a probably pipe zone (savrda, 2007) in deep water sediments during particular time intervals. it can also occur in well oxygenated deposits in deep tier, where oxygenation of pore waters is already low. the intense bioturbation in the uppermost part of the argiles rouges de kheneg formation may be attributed to the increasing supply and higher food availability caused by oxygen levels related to storm events. definite shallow water traces are only represented by protovirgularia. this is somewhat surprising considering the occurrence of shallow water facies in the argiles rouges de kheneg formation. acknowledgement we thank pr. bhawanisingh g. desai (school of petroleum technology, pandit deendayal petroleum university, gandhinagar, india) for his help in the determination of trace fossils. we are grateful to the reviewers, pr. alfred uchman and anonymous reviewer for their constructive comments of the manuscript. references atrops, f. & benest, m. (1981): données biostratigraphiques nouvelles sur l’oxfordien et kimméridgien du djebel nador et tiaret (avant-pays tellien, algérie): conséquences paléogéographiques.– geobios, 1/14, 155–122. doi: 10.1016/ s0016-6995(81)80170-2 atrops, f. & benest, m. (1994): les formations à ammonites du malm dans le bassin tellien, au nord de tiaret: leur importance pour les corrélations avec les séries de l’avant-pays de l’ouest algérien.– in: cariou, e. & hantzpergue, p. (eds.): 3rd international symposium on jurassic stratigraphy, poitiers, 1991.– geobios, 79–91. doi : 10.1016/s0016-6995(94)80127-4 augier, c. (1967): quelques éléments essentiels de la couverture sédimentaire des hauts plateaux.– publication du service géologique de l’algérie, 34, 47–80. azpeitia moros, f. (1933) : datos para el estudio paleontólogico del flysch de la costa cantábrica y de algunos otros puntos de españa.– boletín del instituto geológico y minero de españa, 53, 1–65. baucon, a., bednarz, m., dufour, s., felletti, f., malgesini, g., de carvalho, cn., niklas, kj., wehrmann, a., batstone, r., bernardini, f., briguglio, a., cabella, r., cavalazzi, b., ferretti, a., zanzerl, h., mcilroy, d. (2019): ethology of the trace fossil chondrites: form, function and environment.– earth-science reviews, 202. doi: 10.1016/j. earscirev.2019.102989 benest, m., ouardas, t., perriaux, j & uselle, jp. (1998): dynamique et contrôle de la sédimentation détritique de l’oxfordien supérieur ou kimméridgien supérieur (zone à acanthicum) dans le cadre paléostructurale de la plate-forme ouest algérienne.– bulletin su service géologique de l’algérie, 9/2, 95–121. berra, f. & angiolini, l. (2014): the evolution of the tethys region throughout the phanerozoic: a brief tectonic reconstruction.– in: marlow, l., kendall, c. & yose, l. (eds.): petroleum systems of the tethyan region.– american association of petroleum geologists memoir, 106, 1–27. doi: 10.1306/13431840m1063606 g eologia c roatica belaid et al.: first record of trace fossils from the oxfordian argiles rouges de kheneg formation (tiaret, northwestern algeria) 93 bottjer, dj., droser, ml. & jablonskl, d. (1987): bathymetric trends in the history of trace fossils.– in: bottjer dj. et al. (eds.): new concepts in the use of biogenic sedimentary structures for palaeoenviromental interpretation.– sepm, 3dcifi section, los angeles, 57–65. brede, r., hauptmann, m. & herbig, h-g. (1992): plate tectonics and the intracratonic mountain ranges in morocco–themesozoic-cenozoic development of the central high atlas and the middle atlas.– geologische rundschau, 81, 127–141. bromley, rg. (1990): trace fossils. biology and taphonomy.– special topics in palaeontology series. london, boston, sydney, wellington: unwin hyman, 280 p. bromley, rg. (1996): trace fossils. biology, taphonomy and applications.– chapman & hall, london, 361 p. bromley, r.g. & ekdale, a.a. (1984): chondrites: a trace fossil indicator of anoxia in sediments.– science, 224(4651), 872–874. doi: 10.1126/science.224.4651.872 buatois, l.a., wisshak, m., wilson, m.a. & mangano, m.g. (2017): categories of architectural designs in trace fossils: a measure of ichnodisparity.– earthscience reviews, 164, 102–181. doi: 10.1016/j.earscirev.2016.08.009 caratini, c. (1970): etude géologique de la région de chellala-reibell.– publication du service géologique de l’algérie, 40/21, 311 p. chalouan, a., michard, a., el kadiri, kh., negro, f., frizon de lamotte, d., soto, j.i. & saddiqi, o. (2008): the rif belt.– in: michard, a., saddiqi, o., chalouan, a. & frizon de lamotte, d. (eds.): continental evolution: the geology of morocco structure, stratigraphy, and tectonics of the africa atlantic-mediterranean triple junction. lecture notes in earth sciences, springer, berlin heidelberg, 116, 203–302. doi: 10.1007/978-3-540-770763_5 cherif, a., benyoucef, m., ferré, b., et benhamou, m. (2018): etude sédimentologique et ichnologique de la formation des argiles de saïda (jurassique supérieur) dans les monts de frenda (algérie nord-occidentale).– revue de paléobiologie, genève, 37 (1). cherif, a., bert, d., benhamou, m. & benyoucef, m. (2015): la formation des argiles de saïda (jurassique supérieur) dans le domaine tlemcenien oriental (takhemaret, algérie): données biostratigraphiques, ichnologiques et sédimentologiques.– revue de paléobiologie, genève, suisse, 34/2, 363–384. crimes, tp. & anderson, mm. (1985): trace fossils from late precambrian early cambrian strata of southeastern newfoundland (canada): temporal and environmental implications.– journal of paleontolology, 59, 310–343. dam, g. (1990): palaeoenvironmental significance of trace fossils from the shallow marine lower jurassic neill klinter formation, east greenland.– palaeogeography, palaeoclimatology, palaeoecology, 79, 221–248. doi: 10.1016/00310182(90)90019-4 demircan, h. (2008): trace fossil associations and palaeoenvironmental interpretation of the late eocene units (sw-thrace).– bulletin of the mineral research and exploration (mta) of turkey, 136, 29–47. demírcan, h & uchman, a. (2017): short distance variability of trace fossils in submarine slope and proximal basin plain deposits: a case study from the ceylan formation (upper eocene), gelibolu peninsula, nw turkey.– bollettino della società paleontologica italiana, 56/2, 253–275. dercourt, j., ricou, l.e., & vrielynck, b. (eds.) (1993): atlas tethys palaeoenvironmental maps.– commission de la carte géologique du monde, gauthier-villars, paris, 307 p. elmi, s. & benest, m. (1978): les « argiles de saïda », faciès flyschoïde du callovo-oxfordien du sillon tlemcénien (ouest algérien): stratonomie, environnement, interprétation et évolution paléogéographique.– livre jubilaire jacques flandrin, document des laboratoires de géologie, lyon, 4, 203–261. fenet, b. (1975): recherche sur l’alpinisation de la bordure septentrionale du bouclier africain à partir de l’étude d’un élément de l’orogène nord-magrébien: les monts du djebel tessala et les massifs du littoral oranais.– thèse ès-sciences, université de nice, 301 p. frey, r.w., howard, j.d. & pryor, w.a. (1978): ophiomorpha: its morphologic, taxonomic, and environmental significance.– palaeogeography, palaeoclimatology, palaeoecology, 23, 199–223. doi: 10.1016/0031-0182(78)90094-9 frizon de lamotte, d., leturmy, p., missenard, y., khomsi, s., ruiz, g., saddiqi, o., guillocheau, f. & michard, a. (2009): mesozoic and cenozoic vertical movements in the atlas system (algeria, morocco, tunisia): an overview.– tectonophysics, 475, 9–28. fürsich, f.t. (1973): a revision of the trace fossils spongeliomorpha, ophiomorpha and thalassinoides.– neues jahrbuchfür geologie und paläontologie, monatshefte, 719–735. fürsich, f.t. (1975): trace fossils as environmental indicators in the corallian of england and normandy.– lethaia, 8, 151–172. doi: 10.1111/j.1502-3931.1975. tb01309.x gomez, f., beauchamp, w. & barazangi, m. (2000): role of the atlas mountains (northwest africa) within the african eurasian plate-boundary zone.– geology, 28/9, 775–778. doi: 10.1130/0091-7613(2000)028%3c0775:rotamn%3 e2.3.co;2 halamski, a.t. & cherif, a. (2017): oxfordian brachiopods from the saïda and frenda mountains (tlemcenian domain, north-western algeria).– annales societatis geologorum poloniae, 87, 141–156. doi: 10.14241/asgp.2017.006 kerrn, jph. & warme, je. (1974): trace fossils and bathymetry of the upper cretaceous point loma formation, san diego, california.– bulletin of geologic society of america, 85, 893–900. doi: 10.1130/0016-7606(1974)85%3c893:tfab ot%3e2.0.co;2 książkiewicz, m. (1968): o niektórych problematykach z flszu karpat polskich, część iii. (on some problematic organic traces from the flysch of the polish carpathians. part 3).– rocznik polskiego towarzystwa geologicznego, 38, 3–17. ksiazkiewicz, m. (1977): trace fossils in the flysch of the polish carpathians.– palaeontology polonica, 36, 1–200. malpas, j.a., gawthorpe, r.l., pollard, j.e. & sharp, i.r. (2005): ichnofabric analysis of the shallow marine nukhul formation (miocene), suez rift, egypt: implications for depositional processes and sequence stratigraphic evolution.– palaeogeography, palaeoclimatology, palaeoecology, 215, 239–264. doi: 10.1016/j.palaeo.2004.09.007 pemberton, g.s., frey, r.w. & bromley, r.g. (1988): the ichnotaxonomy of conostichnus and other plug-shaped. ichnofossils.– canandian journal of earth sciences, 25, 866–892. polveche, j. (1960) : contribution à l’étude géologique de l’oranais.– publication du service de la carte géologique, 24, 96 p. richter, t. (1927): die fossilen fährten und bauten der würmer, ein überblick über ihre biologischen grundformen und deren geologische bedeutung.– paläont z, 9, 193–240. rhoads, d.c. & morse, j.w. (1971): evolutionary and ecologic significance of oxygen-deficient basins.– lethaia, 4, 413–428. doi: 10.1111/j.1502-3931.1971. tb01864.x savrda, c.e. (2007): trace fossils and marine benthic oxygenation.– in: miller iii w. (ed.): trace fossils, concepts, problems, prospects. elsevier, arcata, 149–156. doi: 10.1016/b978-044452949-7/50135-2 savrda, c.e. & bottjer, d.j. (1989): trace fossils model for reconstructing oxygenation histories of ancient marine bottom waters: application to upper cretaceous niobara formation, colorado.– palaeogeography, palaeoclimatology, palaeoecology, 74, 49-74. doi: 10.1016/0031-0182(89)90019-9 savrda, c.e., bottjer, d.j. & gorsline, d.s. (1984): development of a comprehensive oxygen-deficient marine biofacies model: evidence from santa monica, santa barbara, and san pedro basins, california continental borderland.– american association of petroleum geologists bulletin, 68, 1179–1192. schafhäutl, k.e. (1851): geognostische untersuchungen des südbayerischen alpengebirges literarischartistische˗anstalt, münchen, p. 208. schlirf, m. (2000): upper jurassic trace fossils from the boulonnais (northern france).– geologica et palaeontologica, 34, 145–213. seilacher, a. (1977): pattern analysis of paleodictyon and related trace fossils.– in: crimes, t.p. & harper, j.c. (eds.): trace fossils 2. geological journal, special issue, 9, 289–334. seilacher, a. (2007): trace fossil analysis.– springer, new york, 226 p. simpson, s. (1956): on the trace-fossil chondrites.– quarterly journal of the geological society, 112, 21–24, london. doi: 10.1144/gsl.jgs.1956.112.01-04.23 tchoumatchenco, p. & khrischev, kh. (1992): le jurassique dans les monts de tiaret et de l’ouarsenis occidental (algérie).– geologica balcanica, 22/5, 29–39. uchman, a. (1995): taxonomy and palaeoecology of flysch trace fossils: нe marnoso -arenacea formation and associated facies (miocene, nortern apennines, italay).– beringeria, 15, 1–115. uchman, a. (1998): taxonomy and ethology of flysch trace fossils: revision of the marian ksiǎzkiewicz collection and studies of complementary material.– ann soc geol polon, 68,105–218. uchman, a. & gaździcki, a. (2006): new trace fossils from the la meseta formation (eocene) of seymour island, antarctica.– polish polar research 27/2, 153–170. uchman, a. (2009): the ophiomorpha rudis ichnosubfacies of the nereites ichnofacies: characteristics and constraints.– palaeogeography, palaeoclimatology, palaeoecology, 276, 107–119. doi: 10.1016/j.palaeo.2009.03.003 welsch, j. (1890): les terrains secondaires des environs de tiaret et de frenda (département d’oran, algérie). thèse présentée à la faculté des sciences de paris pour obtenir le grade de docteur s-sciences naturelles.– série a, no 139; no d’ordre 692. le bigot frères, lille, 204 p. wignall, p.b. (1991): dysaerobic trace fossils and ichnofabrics in the upper jurassic kimmeridge clay of southern england.– palaios, 6, 264–270. doi: 10.2307/3514906 g eo lo gi a c ro at ic a geologia croatica 73/294 www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2024 | 77/2 | 85–97 | 9 figs. | 3 tabs. | article history: manuscript recieved: january 13, 2024 revised manuscript accepted: april 18, 2024 available online: june 21, 2024 keywords: calcareous tufas, manganese district, palaeoenvironmental, reconstruction, mexico 1. introduction calcareous tufa is a sedimentary rock composed of calcium carbonate deposited as calcite, aragonite or dolomite. these deposits are formed mainly by the precipitation of calcium carbonate, associated with karst outcrops on the continent (carcavilla et al., 2019). these deposits are generated in aquatic conditions related to carbonate aquifers that adopt different morphologies and contain remains of micro and macrophytes that have been covered with carbonate, being located around upwellings or are associated with fluvial systems rich in calcareous materials (carcavilla et al., 2019; arenas et al., 2010; pentecost, 2005; ford & pedley, 1996). the calcareous tufa deposits are associated with different environments: along the coast; in areas of saline or alkaline lakes; springs; barriers; margins of fluvial courses; marshes; and fluvial-lacustrine environments, where the dynamics of karstic aquifers control the distribution of such deposits (arenas-abad, 2017). according to pentecost palaeoenvironmental reconstruction of holocene calcareous tufas distributed over a manganese deposit in mexico maría jesús puy-alquiza1,*, raúl miranda-avilés1, miren yosune miranda puy2, pooja vinod kshirsagar1, gabriela a. zanor3 and ma. cristina del rincon-castro4 1 universidad de guanajuato, departamento de minas, metalurgia y geología, división de ingenierías, campus guanajuato, 36000 guanajuato, méxico; (*corresponding author: yosune.puy155@gmail.com) 2 universidad nacional autónoma de méxico, departamento de ciencias agrogenómicas, escuela nacional de estudios superiores unidad león, 37684 guanajuato, mexico 3 universidad de guanajuato, departamento de alimentos, división de ciencias de la vida, universidad de guanajuato, campus irapuato-salamanca, 311 guanajuato, méxico 4 universidad de guanajuato, departamento de ciencias ambientales, división ciencias de la vida, campus irapuato-salamanca, 311 guanajuato, mexico doi: 10.4154/gc.2024.08 abstract the holocene calcareous tufa deposits are located in the north-central sector of the state of hidalgo, mexico. these deposits outcrop on the upper jurassic chipoco formation in the molango manganese district. calcareous tufa deposits correspond to carbonate formations of inactive tufas disconnected from the current hydrological network. to better understand the textural, geochemical, and biological characteristics and environmental conditions during their formation, a detailed study involving field analysis, x-ray diffraction analysis, x-ray fluorescence analysis, and morphometric analysis with light microscopy, and scanning electron microscopy was carried out. similarly, 14c analysis was undertaken to determine the age of the deposit. on this basis, two biofacies were defined, one with stem structures and the other with phyto clasts, bryophytes (plagiomnium cuspidatum), and copepods, limited both at the base and the top by lenticular-shaped erosive surfaces and sigmoidal clinoforms. these bio facies formed in lacustrine and paludal environments, and barrier waterfalls. from a geomorphological point of view, the accumulations of these calcareous tufas originated on slopes and/or at the foot of karstic springs, where the accumulation of material originated from the height of the spring with respect to the bottom of the valley, giving rise to a set of stepped tuffaceous plains with a wedge-shaped profile, colonized by important masses of bryophyte mounds, copepods, and vascular plants. this suggests a swampy environment where sedimentation took place in shallow water accumulations, where there is clear evidence of exposure and pedogenetic modification, indicating wet and dry episodes that translate into seasonal fluctuations in the water table. six mineral phases were observed including silicates, carbonates and arsenates. the 14c analysis indicates that the plant found in the charcoal sample within the calcareous tufa deposit is of holocene age. & viles (1994) and arenas-abad (2017), several factors are required for calcareous tufa deposits to form: warm climate; physicochemical processes favourable for carbonate precipitation; organic structural elements; tectonics; and characteristics of the substrate (lithological composition). carbonate precipitation is influenced by the physical and chemical properties of the water, the amount of co2 degassing, and the development of vegetation (cyanobacteria, mosses, vascular plants), causing different morphologies, such as springs, rivers, and lake barriers, waterfalls, and stromatolites. regarding the physicochemical conditions of the water (jones & renaut, 2010; pentecost et al., 2003; pentecost, 2005; arenas-abad et al., 2010), mention that the waters that form calcareous tufa deposits usually have temperatures below 20°c, while the ph is generally greater than 7 and very frequently around 8 to 8.5, favouring the development of vegetation of the community due to high humidity, and carbonate saturation. concerning the g eo lo gi a c ro at ic a 86 geologia croatica 77/2 precipitation of calcareous tufas, the pressure of co2 plays a very important role, with the most common range of pco2 being between 4x10-4 and 8x10-4 atmospheres (kano et al., 2003; minissale, 2004; dilsiz, 2006; auqué et al., 2009, 2013; arenas et al., 2014). for the accumulation of calcareous tufa deposits to occur, the geo-environmental factor plays a very important role when it interacts with the morpho-structural conditions of the area and the hydrological conditions (viles et al., 2007). all these elements in one way or another regulate the types of precipitate and their rate of growth. based on this, calcite precipitation is physically controlled by the degassing rate of dissolved co2 and water temperature, determining factors that unbalance the ionic solution, while the soil tends to exclusively influence scale nucleation which occurs at upwelling points or along with the turbulent flow, in rapids, jumps, and waterfalls of the fluvial course. the carbonate impregnation of cyanobacterial covers, mosses, and vascular plants occurs both in calm waters and waterfalls with thin water runoffs (carcavilla et al., 2009). the molango manganese district reveals the existence of a series of geomorphological and palaeoenvironmental elements that had gone unnoticed in the descriptions and studies carried out to date and where a series of calcareous tufa deposits can be observed. one of the problems represented by the study of calcareous tufa deposits is the difficulty of recognizing them since their morphologies are highly modified by erosion and diagenesis, so their recognition requires the characterization of the biofacies. another problem is the small number and volume of the outcrops, which are being ignored due to their lack of perceived relevance. taking into account the above, the objectives of this study were: 1) to characterize the geomorphological and geological context on which the calcareous tufa deposits developed; 2) to characterize these deposits from the petrological, mineralogical, and geochemical points of view; and 3) to establish the most probable time range for the development of calcareous tufa deposits using 14c dating, to highlight geomorphological, palaeo-ecological and palaeoenvironmental reconstructions. 2. tectonic and regional geologic setting the study area (fig. 1) is part of the sierra madre oriental physiographic province, formed by the uplift and deformation of jurassic siliciclastic and marine rocks (eguiluz et al., 2000). these deposits represent basin material related to the opening of the gulf of mexico (carrillo & suter, 1982). during this geological time, the tethys sea flooded areas where evaporitic-carbonate banks and platforms were developed (eguiluz et al., 2000). in the manganese district of molango, carbonate rocks from the lower, middle, and upper jurassic can be observed, which correspond to the huayacocotla sector (carrillo & suter, 1982). this sector is located at the southeast end of the sierra madre oriental, corresponding to an anticlinorium, represented by low-angle reverse faults and thrusts (carrillo & suter, 1982). the lower jurassic is characterized by the huayacocotla formation, represented by three members: the lower member (conglomerate, sandstones, siltstones, and mudstone with fusulinids and crinoids); intermediate member (conglomerate, sandstones, siltstones, and mudstone with ammonites); and upper member (sandstones, figure 1. geological map of the study area. g eologia c roatica 87puy-alquiza et al.: palaeoenvironmental reconstruction of holocene calcareous tufas distributed over a manganese deposit in mexico siltstones, mudstone, and conglomerate with continental fossil plants). the middle jurassic is comprised of two units: red layers of the cahuasas formation and the tepexic formation, characterized by sandy limestone, marl, and mudstone with trigonous and oysters. the upper jurassic comprises the santiago, chipoco, and pimienta formations. the santiago formation consists of black and calcareous siltstone, resting concordantly on the tepexic formation. the chipoco formation corresponds to a set of sedimentary rocks that represent the transition zone between the cuenca and platform deposits (hermoso de la torre & martinez-perez, 1972), made up of four lithological units: unit 1, composed of manganese limestone with calcareous mudstone intercalations; unit 2, characterized by calcareous sandstone interbedded with sandy calcareous shale; unit 3, formed of limonite and calcareous mudstone with intercalations of clayey limestone; and unit 4 comprising a limestone sequence rhythmically interbedded with black mudstone, dark gray grain-stones and mudstones, alternating with calcareous mudstone (ochoacamarillo 1996; ochoa-camarillo et al., 1998). according to hermoso de la torre & martínezpérez (1972), the chipoco formation rests concordantly on the mudstone of the calcareous-clay member of the tamán formation (santiago formation) which, in turn, lies below the pimienta formation. at the beginning of the palaeogene, the entire mesozoic sequence was uplifted and folded derived from the laramide orogeny (carrillo-martínez & suter, 1982). during the eocene and early oligocene (54-30 ma), a normal fault system prevailed, forming steep graben and horst fault blocks and volcanic activity (ochoa-camarillo, 1996). the oligocene-miocene (30-3 ma) records the presence of an active intracontinental volcanic arc (trans-mexican volcanic belt). active volcanism together with the laramide orogeny caused changes in the topography and the formation of basins and lakes, allowing great diversification of freshwater fish (ochoa-camarillo et al., 1998). during the quaternary, glaciation effects from climate change, causing vegetation changes can be observed. at the end of the pliocene (2-4 ma), the mafic volcanism that obstructed the drainage of the basins manifested itself and generated palaeo-lakes (lópez ramos, 1972), (fig. 1). 3. study area the study area is located within the manganese district of molango in the north-central sector of the state of hidalgo, and belongs to the municipality of tehuacan de guerrero, within the geographic coordinates 20°98' n and 98° 73' w. the molango manganese district represents the most important manganese deposit in north and central america and one of the ten largest deposits in the world, covering an area of 960 km2 (figure 2), (hermoso de la torre & martinezperez, 1972). the calcareous tufa deposits extend 50 m over the chipoco formation, reaching 5 to 10 m in thickness. macroscopically, it presents as an ochre color, with an irregular wavy base, spongy texture, and massive or stratified structure with decametric strata. one of the characteristics of these deposits is their occurrence in the form of layers on a gently sloped palaeo-topography (< 10°). figure 2. location of the study area. g eo lo gi a c ro at ic a 88 geologia croatica 77/2 4. materials and methods 4.1. characterization of the geomorphological and geological context field reconnaissance was carried out allowing for the selection of outcrops in which a geological section was raised, creation of a stratigraphic profile, and sampling of calcareous tufas with remains of vascular plants, bryophytes, and pieces of coal. samples were taken from both the base and the top of the outcrop. to classify the type of habitat where the calcareous tufa deposits were formed in the molango manganese district, the classification proposed by carcavilla et al. (2019) was taken into account. the classifications of buccino et al. (1978), pedley (1990), and violante et al. (1994) allowed classifying the biofacies of calcareous tufas concerning their biological components. 4.2. analytical methods 4.2.1. petrographic analysis four samples were obtained from the calcareous tufa deposits that outcrop in the manganese district of molango hidalgo. these samples were analyzed using various techniques such as petrographic analysis whereby samples were cut into thin sections with a circular rock cutter and mounted on glass slides with epoxy resins. the samples were ground and polished with carbide shot to a thickness of 0.3 mm. the sections were then covered with glass slides so that the texture and minerals in the stone could be characterized by optical microscopic analysis. the identification and characterization of minerals were carried out employing the olympus bx41 petrographic microscope, using cross-polarized light. 4.2.2. geochemical analysis for determination of their chemical composition, the samples were analyzed using a rigaku nex cg x-ray fluorescence (xrf) spectrometer, using energy dispersive mode (edxrf). the spectrometer has an x-ray tube with a pd anode and maximum power of 50 w (maximum voltage of 50 kv and current of 2 ma), and operates in a he atmosphere. calibration was performed with the mca standard (rigaku patent). 4.2.3. mineralogical analysis to determine the mineral phases, the four samples were analyzed using the ultima iv x-ray rigaku diffractometer with cukα radiation. xrd patterns were compared with the powder diffraction file (pdf) data from international center for diffraction data (icdd) to determine the phases present. 4.2.4. scanning electron microscope (sem-eds) analysis the morphological properties of the four samples were investigated by sem observations without any sample coating. a jeol scanning electron microscope (sem-eds), model jsm-6010 plus/la, was used, operated at 15 kv in a low vacuum, while an energy dispersive spectrometer (eds), attached to the sem, was used for semiquantitative chemical analysis. all the analyses were carried out in the licamm laboratory of the university of guanajuato. 4.3. radiocarbon analysis one sample was dated using the radiocarbon method. a fragment of charcoal found within the calcareous tufa deposits was sent to the beta analytic laboratory in miami florida. vegetable remains (plant) and organic sediments were found inside. the content recovered from the plant remains was 2.6 mg, while the content of the organic sediments was 408.8 mg. the plant was pretreated with acid/alkali/acid for the removal of carbonates and soluble humic acids, while the organic sediment was pretreated with acid only to eliminate carbonate (fig. 3). the plants were dated as they are short-lived and, figure 3. charcoal analyzed for 14c dating. a) facies of calcareous tufa deposits. b, c) sample of charcoal found in calcareous tufa deposits; d) sample of charcoal pretreatment, e) plant pre-treatment with acid/alkali/acid. g eologia c roatica 89puy-alquiza et al.: palaeoenvironmental reconstruction of holocene calcareous tufas distributed over a manganese deposit in mexico therefore, represent a unique event in time. the organic sediment was not dated as it could represent an open system, where carbon could enter or leave the depositional environment. the date of the plant material represents the carbon within the plant cells, while the date of the sediment represents an average of the multiple organic components it contains. based on this, only the plant material was dated. 5. results 5.1. geomorphological, and geological characterization of calcareous tufa deposits 5.1.1. geomorphological and calcareous tufa appearance the topographic characteristics of the molango manganese district have led to tributaries cutting into carbonate deposits, favouring the development of important tufaceous formations during the holocene. along the section between the towns of otongo and chipoco, there are terraced morphologies on the banks of the chipoco river, with little longitudinal development and reduced thickness showing a longitudinal geometry of the calcareous tufa deposits. the calcareous tufa formations discussed in this article are white to yellow in colour, have cavities, and are porous with a large number of trunks observed. russell (1883, 1889) was one of the first to describe carbonaceous tufa types based on structural variation and depositional age. taking into account their classification, the molango calcareous tufa deposits correspond to the lithoid and dendritic types. the lithoid type is presented as a stony variety, in the form of porous and tubular masses, while the dendritic type is characterized by a structure of compact columns with stems branching upwards. these two types can occur in layers of different thicknesses to form a calcareous tufa tower. the origin was possibly in a paludine environment, where the calcareous tufa developed on poorly drained soils, in slopes colonized by hydrophyte macrophytes and bryophyte mounds. waters enriched in calcium carbonate leaked, depositing a vegetal cover on the surface (figure 4 (al)). small ephemeral pools may develop in the valley bottoms and may persist for a sufficient time to allow carbonate fouling of associated macrophytes and aquatic vegetation. microdetrital tufa (lime mud) can also accumulate locally within the pools partly from rainfall on the site and partly from material washed in from the surrounding swamp slopes (figure 4 (al)). the thicker bioclastic material can enter the system by this route and leaf fall can also lead to the deposition of humus-rich layers (gyttja) within shallow and stagnant bodies of water. 5.1.2. classification of biofacies in the calcareous tufa deposits in the calcareous tufa of molango, the biological components developed in the spring system sub-environment and a barreracascade sub-environment, where an abundance of fragments of vascular plant communities, replaced by calcite, are observed. taking into account the biofacies classification (buccino et al., 1978; pedley, 1990; violante et al., 1994), two types of biofacies can be observed in the calcareous tufa deposits in the molango district (table 1): biofacies i (phytoclastic tufa) and biofacies ii (mosse tufa). biofacies i (phytoclastic tufa) represents allochthonous deposits that correspond to a macrodetritic tufa. these facies are formed by fragments of stems and leaves from 5 mm to 7 cm long and figure 4. biofacies in the calcareous tufa deposits: a, b, c) the lithoid type is presented as a stony variety, in the form of porous and tubular masses; d, e, f) the dendritic type is characterized by a structure of compact columns with stems branching upwards bryophyte; g, h, i) bryophyte replaced by calcium carbonate; j, k, l) vascular plants replaced by calcium carbonate. g eo lo gi a c ro at ic a 90 geologia croatica 77/2 with diameters of 0.5 to 1 cm (fig. 5). they are coated with calcite, locally derived within the sedimentation zone. these fragments of vegetable stems are exposed in the upper part of the calcareous deposit. the calcitic envelopes' thickness is variable and usually laminated, with evidence of microbes. sometimes the fragments are arranged parallel to the flow. 5.2. petrological, mineralogical, and geochemical characterization of calcareous tufa deposits 5.2.1. petrological analysis twenty-five thin sections were made of the rock samples collected in the field. the main mineral observed is calcite, table 1. main features of the depositional environments and the associated sedimentary facies. facies geometry of deposits texture and structure characteristics environment photography facies i: phytoclastic tufa tabular, lenticular, and domic; centimeters to decimeters of thickness, and meters to decameters of extension boundstones of plants that grow upwards or pendants. plant stems are recrystallized by calcite. calcite precipitation around the part submerged hydrophilic plants. marshy areas on the banks of rivers and lakes, river floodplains, and areas between river channels. vertical and staggered cascades. facies ii. moss tufa lenticular, plano-convex, and domic; centimeters to meters thickness and decimeters to decameters of lateral spread boundstones of mosses. a succession of centimetric layers and sheets made of mosses whose caulidia and phyllidia are arranged perpendicular or oblique to the deposit surface. these items are covered by calcite and have their interior empty or filled with calcite cement. calcite precipitation around caulidia and phyllidia of mosses, forming mats. waterfalls, waterfall barriers, and small jumps, spray zones; illuminated areas of caves. figure 5. classification of the calcareous tufa facies according to the biological components. g eologia c roatica 91puy-alquiza et al.: palaeoenvironmental reconstruction of holocene calcareous tufas distributed over a manganese deposit in mexico and manganese oxides are minor constituents. textural analysis of the analyzed samples showed that the deposits are composed of calcite coatings on biological substrates (mosses and vascular plants). the mosses are replaced by calcite where spherical structures are observed showing a concentric or radiant internal pattern. vascular plants, especially the tubes, are filled with mosaics of equigranular calcite. microbial structures are generally associated with copepods, bryophytes, vascular plants, trunk fragments, and possible reproductive systems (fig. 6). 5.2.2. mineral phases – x-ray diffraction (xrd) table 2 shows the different mineralogical phases found in the calcareous tufa deposits studied. the dominant mineral phases are silicates (quartz (sio2), and moganite (sio2)), carbonates figure 6. photographs of the thin layers of calcareous tufa deposits. a) the external mould of the bryophyte can be observed, replaced by calcite; b) calcite microcrystals; c) copepod; d) reproductive system. table 2. x-ray diffraction (xrd). mineralogical phases of carbonate tufa deposit. sample xrd xrd diffractogram m1 quartzsio2 moganitesio2 calcite, magnesian (ca, mg) co3 pyrosmalite -(mn) (mn+2 fe)8(si6o15) (oh, cl)10 muscovite (k, na) (al, mg, fe)2(si3.1al0.9) o10(oh)2 hidalgoite pbal3(aso4) (so4) (oh)6 pennantite-1miib mn5 +2 al (si3al) o10(oh)8 wallkilldellite, (ca, mn)4 mn6 +2 as4o16(oh)8 x 18h2o m2 calcite caco3 calcite, magnesian (ca, mg) co3 m3 and m4 calcite caco3 quartz sio2 moganite sio2 g eo lo gi a c ro at ic a 92 geologia croatica 77/2 (calcite (caco3), and magnesian calcite ((ca, mg) co3)). moganite is a mineral that is a type? of chalcedony. the formation of chalcedony is linked to the existing ph in the medium, so the presence of chalcedony is justified in alkaline ph. chalcedony in carbonate tufa deposits is found as a replacement material for calcite and/or dolomite and cementing pores. the presence of silica (sio2) may be due to local geological and environmental conditions. silica could be incorporated through the interaction of silica-rich rocks and water; it may also come from decomposing organic material such as diatoms or other organisms that contain silica in their structures. other identified mineral phases are arsenates (wallkilldellite, hidalgoite), the chlorite group minerals (pennantite), and other phyllosilicates (muscovite, pyrosmalite(mn)). these mineral phases are associated with the molango manganese deposit, which is considered to be a large-scale marine sedimentary deposit typical of the kimmeridgian tithonian in mexico. the calcareous tufa deposits were formed on the chipoco formation, where manganese enrichment occurs, hence the presence of mineral phases related to the manganese deposit. 5.2.3. geochemistry – x-ray fluorescence (xrf) the main mineralogical phases are carbonates, represented by calcite. chemical analyses indicate that calcite (caco3) contains quantities of magnesium (mg), iron (fe) and manganese (mn). other elements that appear are chlorine (cl), sulfur (s), phosphorous (p), aluminum (al), silicon (si), potassium (k), vanadium (v), cobalt (co) nickel (ni), copper (cu), zinc (zn), tin (sn), titanium (ti), strontium (sr), barium (ba), arsenic (as) and lead (pb) (table 3). 5.2.4. microbial structures – scanning electron microscopy (sem-eds) analysis the morphological aspects of the microbial samples are shown in figure 7. in all samples, the sem examination revealed carich particles, and magnesium (mg), aluminum (al), silicon (si), and sulfur (s). wollastonite occurs in all the samples analyzed, it is calcium inosilicate (casio3) that can contain small amounts of iron, magnesium, and manganese substituting for calcium (ca). regarding the biological structures, it is observed that these are covered by calcite formed around the bryophytes, where it is common to distinguish palisades of calcite tubes perpendicular to the substrate. it is important to mention the absence of lithic sediments in the samples. the presence of pyrite microcrystals, circular spheres (microbial), and phytoclasts is common. as for the metals, it can be observed that most of the samples studied contain iron, copper, zinc, manganese, molybdenum, and sulfur. 5.3. radiocarbon dating the results of the radiocarbon dating indicate that by pretreating the charcoal, no carbon was recovered. instead, plant fragments were recovered, which were pre-treated with acid/ alkali to remove carbonate and soluble humic acids. the plant fragments were dated by the 14c method, obtaining the conventional radiocarbon age of 360 ±30 bp. two-time intervals are shown in figure 8, where there is the first interval of 490-421 cal bp, and a second interval of 410-316 cal bp. these data place the deposit of calcareous tufa in the holocene. 5.4. palaeoenvironmental reconstruction the calcareous tufa deposits found in the upper part of the chipoco formation in the molango manganese district correspond to deposits of a spring system sub-environment and a barrera waterfall sub-environment. the sub-environment of a spring system relates to places where groundwater emerges to the surface through fractures or discontinuities, with a horizontal or gently sloping topography, favouring the accumulation of these deposits in conical mounds, frequent in underwater springs (lacustrine and paludine) (capezzuoli et al., 2014; della porta, 2015), while the barrera waterfall sub-environment originates from the accumulation of phytoclasts or calcification linked to plants and microorganisms. the development of a barrier generates a topographic drop immediately downstream, giving rise to a waterfall. the morphology of this sub-environment is a mound composed of clinoforms. the succession of barrier-cascade pairs generates stepped sections (chafetz et al., 1994; ordoñez et al., 2005; arenas-abad et al., 2010; gradziński et al., 2013). the calcareous tufa deposits studied were formed by physicochemical or biological precipitation or by a combination of these two processes. organic factors such as vascular plants' presence have influenced these deposits' geomorphological characteristics. the petrological, morphological, and geochemical characteristics observed in the molango calcareous table 3. chemical compositions of the carbonate tufa deposit obtained with x-ray fluorescence (major elements in wt%, and minor elements in ppm; nd – not determined). sample m1 sample m2 sample m3 sample m4 major elements (wt%) mgo 1.92 0.43 0.32 0.75 k2o 1.38 0.76 0.53 0.37 cao 30.90 57.50 74.80 79.40 al2o3 9.29 2.05 1.32 2.53 sio2 26.10 4.61 2.82 5.42 p2o5 0.16 0.01 0.00 0.04 so3 4.30 0.84 0.99 2.41 tio2 0.42 0.06 0.05 0.01 mno 16.90 15.0 6.19 8.0 fe2o3 8.60 18.7 12.90 1.08 na2o nd nd nd nd minor elements (ppm) v 65 nd 5.36 nd cr nd nd nd nd co 216 17.6 nd 30.2 ni 60.2 21.7 nd 116 cu 28.2 9.64 5.54 32.6 zn 55 32.3 3.17 100 as 42.9 2.07 nd 2.89 sr 402 172 139 415 sn 29.9 11.5 12.6 19.6 sb nd nd nd nd ba 194 nd nd nd hg nd nd nd nd pb 13.3 5.58 2.66 12.6 cl 152 25.6 27.8 nd g eologia c roatica 93puy-alquiza et al.: palaeoenvironmental reconstruction of holocene calcareous tufas distributed over a manganese deposit in mexico figure 7. images obtained with the scanning electron microscope in the samples of the calcareous tufa deposits. a, b) mould of bryophyte stem. c) packing of pentagonal-dodecahedral pyrite microcrystals. d) microbes formed by connected circular spheres. e) detail of circular sphere (microbial). f) phytoclast. g) wollastonite. tufa deposits suggest that they were formed in a marshy environment, located in a disk system in low-lying areas near or associated with lagoons or springs that provided them with water, allowing the colonization of macrophytes, hydrophytes, mounds of bryophytes with little presence of lichens. they represent shallow and stagnant bodies of water, relating to a marshy environment (fig. 9). the palustrine carbonates were formed by periods of saturated water and subaerial exposure, figure 8. results of 14c dating. g eo lo gi a c ro at ic a 94 geologia croatica 77/2 indicating fluctuations due to seasonal or long-term climatic changes. these deposits provide evidence of pedogenic carbonate precipitation, a process that suggests calcite saturation in the vadose zone fluids. alonso-zarza (2003) suggests that marsh deposits are formed mainly during periods of very low subsidence, with limited accommodation space for basins with more fill, giving way to facies deposition in more shallow systems. furthermore, platt & wright (1992) suggest that marsh deposits are common in relatively stable basins, usually formed during periods of tectonic quiescence where clastic supply from alluvial-fluvial systems is reduced. it is then suggested that the sedimentation took place in shallow water accumulations, where there is a clear evidence of exposure and pedogenic modification, indicating wet and dry episodes that translate into seasonal fluctuations of the water table. according to golubic (1969), calcareous tufa deposits are subject to subaerial exposures where such deposits are susceptible to local changes within drainage patterns and short-term fluctuations in the water table that can lead to stream incision, thus the development of these deposits is cyclic and the deposition ends at the end of a natural cycle by incision and erosion of the deposits. this subaerial exposure occurred in the calcareous tufa deposits studied where the development of vadose calcite cement and the mobilization of fe and mn are observed, the latter precipitated at the air/water interface. 6. discussion in the molango district, the origin of the carbonates that make up the tufa deposits is linked to the nature of karstic aquifers. the water flows generated by the calcareous tufas come from karstic massifs and are associated with meteoric waters with temperatures usually close to 10ºc with slightly basic ph values (7.5 -8.4), and calcium concentrations between about 30 mg l-1 and 60 mg l-1 (merz preiß & riding, 1999; pentecost & zhaohui, 2002; pentecost, 2005). according to slack (1967), the origin of calcareous waterfalls is primarily in the precipitation of calcium carbonate due to the degassing of the dissolved co2 and the temperature of the water. in biochemical precipitation, plants are an essential component, and the loss of co2 could be linked to the extraction of co2 from the water through the photosynthesis of macrophytes, bryophytes (mosses), filamentous algae, diatoms, charophyte algae, cyanobacteria, bacteria, vascular plants, and prokaryotes. especially, the organic substrate plays a key role in the nucleation of calcite incrustations and the primary porosity is provided by the calcareous tufa material (pentecost, 2005). an important characteristic of calcareous tufa deposits is that their study allows us to understand the regional evolution of the geographical areas in which they are located, providing information on their karstic evolution, their tectonic behaviour, and the gradation or incision processes of their watercourses. in the molango district, the calcareous tufa deposits are considered the only morphological witnesses that are found interacting with the karstic morphology, being able to link the origin of the carbonated tufas with the dissolution processes developed on the exo-karstic morphologies modeled in a more or less closed environment. taking into account the pedley (1990) classification, the deposits of calcareous tufa molango correspond to phytoherms, where the tufa constructions are porous, derived from primary factors linked to the insertion of multiple plant elements (hydrophytes and semiaquatic macrophytes) colonized by microfilms cemented by calcitic carpets with a low content of magnesium. these deposits are composed of multiple plant devices generally cemented after their sedimentation. under magnification, the calcified stem casts are 2 cm long, 2-3 mm in diameter, and are covered with micrite (fig. 4). the biofacies i was formed on gentle slopes, in lacustrine and swampy environments, favouring hydrophilic soil development plants, for which stem and phytoclast abound. biofacies ii (bryophyte hummocks tufa) alternates with biofacies i. bryophytes are non-vascular plants, do not have roots or vascular tissue, and absorb water and nutrients from the air over their entire surface. most of them just reach a few centimetres in height, they grow in places where other plants could not, such as on the surface of rocks, walls, pavements, etc. bryophytes grow in humid and shady environments but can be found in diverse and even extreme habitats, from deserts to arctic areas. in the facies described, the dominant species corresponds to plagiomnium cuspidatum. these bryophytes grew on carbonate rocks, which formed figure 9. palaeoenvironmental reconstruction. diagram illustrating the associations of calcareous tufa lithofacies in a paludal environment. a) paludal environment resurgence point; b) bryophyte hummocks and phytoclasts; c) cascade constituted by calcareous tufas; d) palaeosols. modelled from calcareous tufa deposits of molango, hidalgo, mexico (modified from pedley, 1990). g eologia c roatica 95puy-alquiza et al.: palaeoenvironmental reconstruction of holocene calcareous tufas distributed over a manganese deposit in mexico mounds developed in a palustrine environment. the aforementioned facies is made up of a succession of centimetre layers and sheets of hummocky bryophytes that are arranged perpendicular or oblique to the surface of the deposit, and formed in small stepped cascades (fig. 5). plagiomnium cuspidatum, also known as toothed or “baby-tooth”, is a species of thyme-moss that originated in north america, but can now also be found throughout middle america, africa, northern and southern asia (excluding china), and europe. copepods have been observed within this species. the facies arrangement in all the environments indicates the initial incision of the fluvial network, subsequent development of ponded/shallow lacustrine areas, and formation of cascades on steps in the palaeo-relief (carcavilla et al., 2019). the sampling points studied indicate that the present facies are associated with marsh carbonates formed by periods of saturated water and subaerial exposure, indicating fluctuations due to seasonal or long-term climate changes. these deposits provide evidence of pedogenic carbonate precipitation, a process that suggests calcite saturation in the vadose zone fluids. considering the model proposed by platt & wright (1992) for marshy environments, the deposits studied were deposited in a moderate climate, characterized by the presence of vascular plants, bryophytes, and rhizolites. the work of alonsozarza (2003) suggests that marshy deposits are formed mainly during periods of very low subsidence, with limited accommodation space for basins with more fill, giving way to a facies deposition in shallower systems. furthermore, platt & wright (1992) suggest that salt marsh deposits are common in relatively stable basins, typically formed during periods of tectonic inactivity where the supply of clastic material from alluvial-fluvial systems is reduced. it is then suggested that sedimentation took place in shallow water accumulations, where there is clear evidence of exposure and pedogenic modification, indicating wet and dry episodes that translate into seasonal fluctuations in the water table. calcareous tufa deposits formed under these conditions are very common in tropical forests where the presence of plant matter is common. the plant structures found in the calcareous tufa deposits were dated using 14c, and a holocene age was obtained. the holocene has been catalogued as one of the quaternary epochs in which the formation of calcareous tufa deposits occurred throughout all the karstic regions of the planet. this was due to the increase in atmospheric co2 during said period (griffiths & pedley, 1995). in hidalgo, during the holocene, mafic volcanism obstructed the drainage of basins, generating karst palaeo-lagoons where a great diversity of copepods, calanoids and cyclopoids as well as structures of stems and vascular plants were replaced by calcium carbonate. this formed a part of the biofacies of the calcareous tufa deposits (lópez ramos, 1972; fernández-badillo et al., 2016). regarding the mineral phases and chemical composition, the calcareous tufa deposits are mainly composed of calcium carbonate, varying its composition in some samples such as m1, where the presence of other minerals is observed (silicates and arsenates) as a result of its proximity to the molango manganese deposit, which exerted specific conditions for formation of the calcareous tufa deposits, influencing the texture, colour and characteristics of these deposits. 7. conclusion the calcareous tufas of molango have their origin in springs located on the slopes of gently sloping valleys and at the foot of karstic springs related to a marshy environment. considering the model types proposed by pedley (1990), the calcareous tufa deposits studied originated in a palaeoenvironment in their distal part, where cascading formations dominated by mounds of bryophytes, vascular plants, and phytoclasts, and associated with local channels, can be observed. these have an almost horizontal shape with a gentle slope, constituting a series of terraces that present properties of the paludal environment. its longitudinal development is in the form of a cascade of small to moderate growth with concave profiles, where bryophytes, lichens and vascular plants tend to adapt to a centimetre jump in terraces developed parallel to the watercourse, providing progradation structures downstream. the sedimentation of the calcareous tufa in molango took place in shallow water accumulations, where there is clear evidence of exposure and pedogenic modification, indicating wet and dry episodes that translate into seasonal fluctuations in the water table. precipitation due to the physico-chemical degassing is the main factor for the deposition of calcareous tufa deposits. these carbonatic accumulations, rich in vegetal remains and not exclusive of karstic substrates, are precipitated in springs, where they formed deposits consisting of calcite with a low magnesium content, and are generally not stratified. in addition, they are formed by bodies of irregular distribution, scarce lateral continuity, are poorly to strongly lithified, and of different petrographic facies. their genesis and development are determined by tectonics and/or trends towards the aggravation or incision of river networks during the holocene. acknowledgment our thanks to the licamm laboratory for their support in carrying out the x-ray diffraction, x-ray-fluorescence, and sem analyses. special thanks to the beta analytic laboratory for the care and support in performing the c14 analysis. we thank the ciic 2023 institutional call for scientific research for the support for the dating of 14c. funding we thank the ciic 2023 institutional call for scientific research for the support for the dating of 14c. references alonso zarza, a.m. (2003): palaeoenvironmental significance of palustrine carbonates and calcretes in the geological record.– earth. sci. rev., 60, 261–298. doi: 10. 1016/s0012-8252(02)00106-x arenas abad, c., vázquez-urbez, m., pardo-tirapu, g. & sancho-marcén, c. (2010): fluvial and associated carbonate deposits.– dev. sedimentol., 61, 133–175. doi: 10.1016/s0070-4571(09)06103-2 arenas abad, c. (2017): tobas y facies asociadas. una factoría de carbonatos continentales en el cuaternario.– enseñ. cien. tierra., 25, 65–73. doi: 471050/110020171023 arenas, c., osácar, c., sancho, c., vázquez-urbez, m., auqué, l. & pardo, g. (2010): seasonal pentecost record from recent fluvial tufa deposits (monasterio de piedra, ne spain).– sedimentol. stable. isot. data., geological society, london, special publications., 336/1, 119–142. doi: 10.1144/sp336.7 g eo lo gi a c ro at ic a 96 geologia croatica 77/2 arenas, c., vázquez-urbez, m., auqué, l., sancho, c., osácar, c. & pardo, g. (2014): intrinsic and extrinsic controls of spatial and temporal variations in modern f luvial tufa sedimentation: a thirteen-year record from a semi-arid environment.– sedimentol., 61, 90–132. doi: 10.1111/sed.12045 auqué, l.f., acero, p., gimeno, m.j., gómez, j.b. & asta, m.p. (2009): hydrogeochemical modeling of a thermal system and lessons learned for co2 geologic storage.– chemi. geol., 268/3, 324–336. doi: 10.1016/j.chemgeo.2009.09.011 auqué, l., arenas, c., osácar, c., pardo, g., sancho, c. & vázquez-urbez, m. (2013): tufa sedimentation in changing hydrological conditions: the river mesa (spain).– geol. acta., 11/1, 85– 102. doi: 10.1344/105.000001774 buccino, g., d’argenio, b., ferreri, v., brancaccio, l., ferreri, m., panichi, c. & stanzione, d. (1978): i travertini della bassa valle del tanagro (campania); studio geomorfologico, edimentológico e geochimic.– boll. soc. geol. ital., 97/4, 617–646. doi: 10.1016/00370738(90)90124-c capezzuoli, e., gandin, a. & pedley, m. (2014): decoding tufa and travertine (freshwater carbonates) in the sedimentary record: the state of the art.– sedimentol., 61/1, 1–21. doi: 10.1111/sed.12075 carcavilla, l., de la hera, á., fidalgo, c. & gonzález, j.a. (2009): formaciones tobáceas generadas por comunidades briofíticas en aguas carbonatadas.– in: vv.aa. bases ecológicas preliminares para la conservación de los tipos de hábitat de interés comunitario en españa.– ministerio de medio ambiente y medio rural y marino. madrid, 62 p. carcavilla, l., vegas, j. & cabrera, a.m. (2019): establecimiento de una tipología específica de formaciones tobáceas. serie. metodologías para el seguimiento del estado de conservación de los tipos de hábitat.– ministerio para la transición ecológica, madrid, 20 p. carrillo-martínez, m.& suter, m. (1982): tectónica de los alrededores de zimapán, hidalgo, in libro-guía de la excursión geológica a la región de zimapán y áreas circundantes early.– in: alcayde, m. & de cserna, z.: vi convención geológica nacional. sociedad geológica mexicana, mexico, 1–20. chafetz, h.s., srdoc, d. & horvatincic, n. (1994): diagenesis of plitvice lakes waterfall and barrier travertine deposits.– geograph. phys. quat., 48/3, 247–255. doi: 10.7202/033006 della porta, g. (2015): carbonate build-ups in lacustrine, hydrothermal, and fluvial seƫ ngs: comparing depositional geometry, fabric types, and geochemical signature.– geol. soc., london, special publications, 418, sp418-4. doi:10.1144/sp418.4 dilsiz, c. (2006): conceptual hydrodynamic model of the pamukkale hydrothermal field, southwestern turkey, based on hydrochemical and isotopic data.– hydrogeol. j., 14/4, 562–572. doi: 10.1007/s10040-0050001-4 eguiluz de antuñano, s., aranda garcía, m. & marrett, r. (2000): tectónica de la sierra madre oriental, méxico.– bol. soc. geol. mex., 53, 1–26. doi: 10.18268/bsgm2000v53n1a1 fernández-badillo, l., manríquez-morán, n. l., castillo-cerón, j. m., goyenechea, i. (2016): análisis herpetofaunístico de la zona árida del estado de hidalgo.– rev. mex. bio., 87/1, 156–170. doi: 10.1016/j.rmb.2016.01.009 ford, t.d. & pedley, h.m. (1996): a review of tufa and travertine deposits of the world.– earth. sci. rev., 41/3–4, 117–175. doi: 10.1016/s00128252(96)00030-x gradziński, m., hercman, h., jaśkiewicz, m. & szczurek, s. (2013): holocene tufa in the slovak karst: facies, sedimentary environments, and depositional history.– geol. quat., 57/4, 769–788. doi: 10.7306/gq.1131 golubić, s. (1969): cyclic and noncyclic mechanisms in the formation of travertine.– internationale vereinigung für theoretische und angewandte limnologie.– verhandlungen, 17/2, 956–961. doi: 10.1080/ 03680770.1968.11895941 griffiths, h.i. & pedley, h.m. (1995): did changes in late last glacial and early holocene atmospheric co2 concentracions control rates of tufa precipitation.– the holocene, 5/2, 238–242. hermoso de la torre, c. & martínez-pérez, j. (1972): medición detallada de formaciones del jurásico superior en el frente de la sierra madre oriental.– bol. asoc. mex. geol. petroleros, 24/1–3, 45–63. jones, b. & renaut, r.w. (2010): calcareous spring deposits in con tinental settings.– dev. sedimentol., 61, 177–224. doi: 10.1016/s00704571(09)06104-4 kano, a., matsuoka, j., kojo, t. & fujii, h. (2003). origin of annual laminations in tufa deposits, southwest japan.– palaeogeol. palaeoclimatol. palaeoecol., 191/2, 243–262. doi: 10.1016/0031-0182(02)00717-4. lópez-ramos, e. (1972): estudio del basamento ígneo y metamórfico de las zonas norte y poza rica (entre nautla, ver. y jiménez, tamps.).– bol. asoc. mex. geol. petroleros., 24, 265–323. merz-preiß m. & riding r. (1999): cyanobacterial tufa calcification in two freshwater streams: ambient environment, chemical thresholds, and biological processes.– sediment. geol., 126, 103–124. doi: 10.1016/ s0037-0738(99)00035-4 minissale, a. (2004): origin, transport, and discharge of co2 in central italy.– earth-sci. rev., 66/1, 89–141. doi: 10.1016/j.earscirev.2003.09.001 ochoa-camarillo, h.r. (1996): aspectos bioestratigráficos, palaeoecológicos y tectónicos del jurásico (anticlinorio de huayacocotla) en la región de molango, hidalgo.– in: gómez-caballero, a. & alcayde-orraca, m. (eds.): ii convención sobre la evolución geológica de méxico y recursos asociados, pachuca, hidalgo, méxico. universidad autónoma del estado de hidalgo, instituto de investigaciones en ciencias de la tierra, uaeh, instituto de geología, unam, simposio y coloquio, mexico. ochoa-camarillo, h., buitrón, b.e. & silva-pineda, a. (1998): contribución al conocimiento de la bioestratigrafía, palaeoecología y tectónica del jurásico (anticlinorio de huayacotla) en la región de molango, hidalgo, méxico.– rev. mex. cien. geol., 15/1, 57–63. ordóñez, s., marơ n, j.g., del cura, m.g. & pedley, h.m. (2005): temperate and semi-arid tufas in the pleistocene to recent fluvial barrage system in the mediterranean area: the ruidera lakes natural park (central spain).– geomorphol., 69/1, 332–350. doi: 10.1016/j.geomorph.2005.02.002 platt, n.h. & wright, v.p. (1991): lacustrine carbonates facies models, facies distributions, and hydrocarbon aspects.– in: anadón, p., cabrera, l. & kelts, k. (eds.): lacustrine facies analysis. special publication of the international association of sedimentologists. ghent, belgium. inter. assoc. sedimentol., 13, 57–74. doi: 10.1002/9781444303919. ch3 pedley, h.m. (1990): classification and environmental models of cool freshwater tufas.– sediment. geol., 68, 143–154. doi: 10.1016/00370738(90)90124-c pentecost, a. & viles, h. (1994): a review and reassessment of travertine classification: geography.– phys. quat., 48, 305–14. doi: 10.7202/033011ar pentecost, a. & zhaohui, z. (2002): bryophytes from some tra vertinedepositing sites in france and the uk: relationships with climate and water chemistry.– j. bryol., 24/3, 233–241. doi: 10.1179/ 037366802125001402 pentecost, a., jones, b. & renaut, r.w. (2003): what is a hot spring?– canadian j. earth. scien., 40/11, 1443–1446. doi: 10.1139/e03-083 pentecost, a. (2005): travertine.– springer berlín-heidelberg. 445 p. doi: 10.3141/pp445a platt, n.h. & wright, v.p. (1992): palustrine carbonates and the florida everglades: towards an exposure index for the freshwater environment?– g eologia c roatica 97puy-alquiza et al.: palaeoenvironmental reconstruction of holocene calcareous tufas distributed over a manganese deposit in mexico j. sediment. petrol., 62, 1058– 1071. doi: 10.1306/d4267a4b-2b26-11d78648000102c1865d russell, i.c. (1883): sketch of the geological history of lake lahonton.– u.s. geology survey annu. rep., 3, 189–235. russell, i.c. (1889): quatemary history of mono valley, california.– u.s. geology survey annu. rep., 8, 261–394. slack, k.v. (1967): physical and chemical description of birch creek, a travertine depositing stream, inyo county, california.– us government printing office. doi: 10.3133/pp549a viles, h.a., taylor, m.p., nicoll, k. & neumann, s. (2007): facies evidence of hydroclimatic regime shifts in tufa depositional sequences from the arid naukluft mountains, namibia.– sediment. geol., 195/1, 39–53. doi: 10.1016/j.sedgeo.2006.07.007 violante, c., ferreri, v., d’argenio, b. & golubic, s. (1994): quaternary travertines at rochetta a volturno (isernia, central italy). facies analysis and sedimentary model of an organogenic carbonate system.– in: premeeting fieldtrip guidebook, a1, international association of sedimentologists, ischia’94, 15th regional meeting, italy, 5–23. 2017 | 70/2 | 87–92 | 10 figs. | 3 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction and geological setting the investigated well is located in the southern part of the da­ nube-tisza interflow, hungary. samples for analysis were taken from the lower pannonian age basal marl succession, namely from the endrőd marl formation (juhász, 1992; 1998). this basal marl sequence is an initial member of the pannonian-plio­ cene age prograding – dominantly siliciclastic – lacustrine selfsystem (magyar et al., 2013). in the early stage of deposition due to the rapid thermal subsidence of the pannonian basin, a so called „starved” sedimentation phase formed in the basin. dur­ ing this stage, the siliciclastic sediment input was limited to the edges of the depocentre and a carbonate rich sequence was de­ posited almost throughout the pannonian basin area. this se­ quence generally began with a high carbonate content calcareous marl, to marl sequence (tótkomlós calcareous marl member) overlain by a deep water, pelagic clay-marl sequence (nagykörű claymarl member), developed with a continuous transition from the underlying carbonate rich rocks (juhász, 1992; 1998). the carbonate content decreases upwards, caused by the increasing terrigenous material input (due to the prograding shelf-system), providing a characteristic and easy to recognize wireline pattern (figure 1). in the study area, the calcareous marl-marl sequence developed almost everywhere except for the south-western, shallowmost part of the basin (figure 2). the calcareous marl has several lithofacies, but in general dark grey, black, laminated-microlaminated facies were deposited in the deep basin areas, while under the shallow water con­ ditions light grey – yellowish or brownish grey, whitish coloured, massive or laminated facies accumulated (juhász, 1992; 1998; lemberkovics, 2016). the investigated samples represent pore characterization, acoustic and permeability measurements on core plug triplets, from the miocene tótkomlós (calcareous marl) formation of the pannonian-basin, hungary péter koroncz1, péter ács1, viktor lemberkovics2 and ferenc fedor1 1 geochem ltd., viola str. 55/1., h-7761 kozármisleny, hungary; (geochem@geochem-ltd.eu) 2 rag hungary ltd., bocskai rd. 134-146., h-1113 budapest, hungary; (viktor.lemberkovics@rag-hungary.hu) doi: 10.4154/gc.2017.09 abstract the tótkomlós calcareous marl (tcm), a member of the late miocene endrőd formation was investigated as a potential cap and source rock and also as a local tight reservoir in the pannonian basin. only a limited dataset is available for petrophysical characterisation of this formation. the study reports on a complex measurement campaign performed on three core triplet samples of the tótkomlós calcareous marl, including pore structure and petrophyiscal analysis at various pressure conditions. direct laboratory measurements of compressional (p) and shear (s) wave velocities on oriented rock samples provide information about the anisotropic behaviour of the studied samples. a quantitative description of seismic anisotropy can improve the quality of seismic data processing. pore structure investigations indicated plate-like materials with a typical pore throat size between 75-110 nm. gas permeability measurements showed very low permeability values in the order of magnitude between 10-16-10-18 m2. weak acoustic anisotropy is observed both for pand swaves. decreasing anisotropy with increasing confining pressure indicated that the samples become less anisotropic with increasing effective stress. the shallow water facies (figure 2. represents approximately the palaeo-geomorphology on which deposition of the calcareous marl occurred). their colour is generally yellowish grey to grey, mainly massive, but sometimes laminated, occasionally organic rich bands, layers of few – ten centimetres scale carbonate rich sandstone layers are interbedded with the monotonous calcare­ ous marl in the core samples (figure 3). article history: manuscript received january 31, 2017 revised manuscript accepted may 26, 2017 available online june 28, 2017 keywords: calcareous marl, acoustic anisotropy, pore structure figure 1. a typical log pattern of the tótkomlós calcareous marl member as recorded in a battonya borehole. 1. calcareous marl, 2. limestone, 3. marl, 4. metamorphic basement, 5. clay-marl, 6. core sample with the measured carbonate content (modified after magyar et al., 2001). g eo lo gi a c ro at ic a geologia croatica 70/288 2. theoretical background of thomsen’s anisotropy parameters in the case of elastic materials, the relationship between stress and strain can be described by hooke’s law (auld, 1973): s eij ijkl klc= (1) where: s – the second-rank stress tensor e – the second-rank strain tensor i, j and k, l = 1, 2, 3 indicating one of three orthogonal axes c – the fourth-rank stiffness tensor with 81 tensor compo­ nents symmetry of the stress and strain tensors, as well as internal energy arguments lead to reduction of the number of indepen dent elements to 21 (hemsing, 2007). elastic properties of shales and shale-type rocks (as well as calcareous marls) are known to be anisotropic, typically considered to have a transversely isotropic (or hexagonal) symmetry with a symmetry axis perpendicular to the bedding plane. the main sources of anisotropy are layering (ti symmetry), the pre­ ferred orientation of clay minerals, microcracks and pores. in the case of vertically transversely isotropic (vti) materials with hexagonal symmetry, the stiffness tensor could be de­ scribed by 5 independent tensor components. c c c c c c c c c c c c cij = − − 11 11 66 13 11 66 11 13 13 13 33 44 2 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 00 0 0 0 0 0 0 0 0 0 44 66 c c                     (2) elastic constants (c11, c33, c44, c66, c13) that describe a vti medium as a function of phase velocities are given by thom­ sen (1986): c vp11 90 2= r , (3) c vp33 0 2= r , (4) c vs44 0 2= r , (5) c vsh66 90 2= r , (6) c c v c c c c cp 13 44 45 2 11 33 44 11 33 1 2 2 4 = − + − − − − −        (4 ) ( )2 2r , / (7) figure 2. basal pannonian (base calcareous marl member) twt seismic depth map of the study area. the investigated well is highlighted with the red circle. calcareous marl is non-deposited or eroded at the reddish coloured acreages (lemberkovics, 2016). figure 3. core photo and its macroscopic description of the investigated sediments. various rock types or subfacies were identified in the calcareous marl sequence (lemberkovics, 2016). the colour code of the rectangles highlights the same rock facies. where vp,90, vp,0, vs,0 and vsh,90 are the compressional and shear wave velocities measured in the different orientations according to figure 5. and r is the bulk density of the sample. thomsen’s anisotropy parameters (e, g, d) which are usually used in depth migration in seismics are dimensionless combina­ tions of elastic moduli that characterize transversely isotropic materials. they are defined in the following way: e = −c c c 11 33 332 (8) g = −c c c 66 44 442 (9) d = + − − − ( ) ( ) ( ) 2 2c c c c c c 13 44 33 44 33 33 442c (10) where e is the p-wave anisotropy factor, g is the sh-wave anisotropy factor and δ is a more complicated expression that may be interpreted as a measure of the anellipticity of the p wave curve (cholach & schmitt, 2006). as thomsen (1986) de­ g eologia c roatica koroncz et al.: pore characterization, acoustic and permeability measurements on core plug triplets, from the miocene tótkomlós (calcareous marl) ... 89 scribed, δ is the difference between the smallest offset normal moveout (nmo) velocity and vertical velocity to interpret the small avo response (tsvankin, 1997, ostadhassan et al., 2012). depth migration algorithms in seismic processing require thomsen’s e and d values, and these parameters can reliably be calculated from direct laboratory measurements. in the case of sedimentary rocks, values of e, g and d are generally in the same order of magnitude, usually smaller than 0.2. moreover, the values are typically higher than 0 in most rocks but negative values are also possible (thomsen, 1986). 3. samples three plug-triplet samples were taken from a homogenous part of the calcareous marl core sections and are macroscopically characterised in table 1. table 1. macroscopic description of investigated core sections. s-01 light brown calcareous marl bands (thickness 1-3 cm). transitions from the lighter bands to the darker ones are continuous. s-02 light yellowish-greyish brown calcareous marl with disperse organic matter. s-03 greyish brown, homogenous calcareous marl. 4. test methods an ultrasonic pulse-transmission technique was used to deter­ mine the pand s-wave velocities. in this case two transducers are placed on the end faces of the samples. the frequency of the transducers used for measurements was centred around 1 mhz, both for compressional and shear waves. travel times for velo city data were determined with a „first-break” record (figure 4). for an accurate and exact determination of flying times, a new algo­ rithm was developed based on the akaike information criteria (akaike, 1973, koroncz & fedor, 2016). previous stud­ ies (e.g. dellinger & vernik, 1994; hornby, 1998) con­ firmed that ultrasonic laboratory measurements represent phase velocities. for the analysis of acoustic anisotropy, a multicore test method was used. in this case, multiple 1” diameter plugs were drilled parallel (90°), perpendicular (0°) and at 45° to bedding planes from a larger sample (figure 5). multi-core methods have been used by many authors to quantify anisotropy (e.g. johnston & christensen, 1995; vernik & liu, 1997; hemsing, 2007) however there are dis­ advantages of the multi-core method. for example, coring may sample different heterogeneities of the material (hemsing, 2007). figure 4. a typical record of compressional (above) and shear (below) waveforms with first-break detection using a modified akaike information criteria (saic) algorithm. figure 5. schematic figure of multicore sampling with the polarization directions of shear wave transducers used for velocity measurements (martínez & schmitt, 2011). for the investigation of the effect of effective stress, measurements were carried out in a high pressure triaxial cell in the range of 0-50 mpa effective stress using 5 mpa pressure incre­ ments. plugs were dried at 60°c to preserve the chemically bound water in the lattice of clay minerals, and were stored in a desic­ cator before measurement. in order to prevent contamination of samples, coupling media were not used. due to the low coupling, measurement error is slightly higher at 0 mpa effective stress. at higher confining pressures, the rms (root-mean-square) error of velocities was less than 1%. for investigating the stress sensitive behaviour of porosity, „boyle’s law single cell method“ (api, 1998) was used to deter­ mine porosity using 10 mpa pressure steps. helium gas perme­ abilities were also measured with the „pressure-falloff, axial gas flow measurement technique” (api, 1998) at a constant pres­ sure of 15 mpa. g eo lo gi a c ro at ic a geologia croatica 70/290 for pore structure measurements, plugs with different diameters (1”, 9 mm) were studied. every sample was dried at 60 °c in a drying oven for a week prior to measurement. the skeletal volume of plugs with 1” diameters were measured at 25 °c with a pentapyc 5200e (ppy-30t) instrument. knowing the geometric volume and the skeletal volume, the he­ lium porosity (φhe) of the plugs was calculated. skeletal density (ρskeletal) and bulk density (ρbulk) were also calculated from the measured data. the n2 and co2 adsorption-desorption isotherms of small plugs (9 mm diameter) were measured with a quantachrome au­ tosorb as-1 instrument. after the drying process the samples were outgassed for 24 h at 60 °c before measurement. physisorp­ tion tests were carried out with n2 (at 77 k) and co2 (at 273 k) gases, in the case of n2 gas bet (brunauer-emmett-teller method) surface area (sbet), total pore volume (vtot) parameters were calculated. the co2 gas is very useful for exploring the mi­ cropore structure of the samples (cazorla-amoros et al., 1996), the micropore surface area (smic) and micropore volume (vmic) were determined with the dubinin-radushkevich method. a quantachrome poremaster-60 gt instrument was used during the mercury intrusion porosimetry (mip) tests. the maxifigure 6. acoustic wave velocities of cores with different orientations at sample-01 and -02. figure 7. calculated elastic constants and anisotropic parameters as a function of effective stress. g eologia c roatica koroncz et al.: pore characterization, acoustic and permeability measurements on core plug triplets, from the miocene tótkomlós (calcareous marl) ... 91 mum (420 mpa) and minimum (1.5 kpa) applied pressure corre­ sponds to cylindrical pore sizes of 3 nm and 800 μm, respectively. contact angles were determined with a mercury contact anglometer (quantachrome) as an average value of three independent measurements. mip was used to investigate the pore throat size distribution in the macroand mesopore region as well as the mer­ cury porosity (φhg) and surface area (shg) of the samples. 5. results and interpretation figure 6. shows acoustic velocity measurements as a function of confining pressure. all of the cores show an increase in velocity with increasing pressure. this is the result of self-sealing, as pores and microcracks begin to close when a sample is pressurized. plugs drilled parallel to bedding show higher velocities than cores drilled perpendicularly to bedding. the velocities of 45° cores were between these values. velocities perpendicular to bedding increase more with pres­ sure, which could suggest that pores in the samples are aligned horizontally (martínez et al., 2012). figure 7. presents the calculated elastic constants and anisotropy parameters as a function of effective stress in the case of sample-01 and sample-02. weak anisotropy is observed in both samples, sample-01 showing slightly higher anisotropy values compared to sam­ ple-02. for sample-01 compressional wave anisotropy (e) measured at 5 mpa is up to 11.5%, while shear wave anisotropy (g) of 6.5% was observed. both pand s-wave anisotropy (e, g) de­ creased with increasing confining pressure, so indicating that the samples become less anisotropic with increasing effective stress. in the case of the third plug-triplet (sample-03) higher ani­ sotropy could be observed (figure 8). although macroscopically no difference could be observed between the samples, the much lower porosity (5.07 %) in the case of sample s-03-90° (drilled parallel to bedding planes) indicated that plug-triplets may not represent the same rock type. the explanation of this phenome­ non requires a more detailed petrological characterization (in­ cluding thin section analysis, xrd, dta) in the future. gas permeability measurements indicate very low permea­ bility values in the order of magnitude between 10-16-10-18 m2. since pressure fall-off permeability data are less reliable in such figure 8. acoustic velocity measurements of sample-03. figure 9. porosity reduction due to increasing effective stress in the case of samples perpendicular to bedding. figure 10. typical co2 (left) and n2 (right) adsorption-desorption isotherms of plugs. g eo lo gi a c ro at ic a geologia croatica 70/292 a low permeability range, these measurements will be measured in a future work by a pressure pulse decay (ppd) technique that provides more accurate results in the case of permeabilities lower than 10-15 m2 (fedor et al., 2008). the decrease of porosity is clearly observed during measure­ ments as figure 9. shows. initial porosity values of tested samples vary between 10-15 % (table 2). porosity reduction due to in­ creasing effective stress can reach 10% in the 50 mpa range. table 2. test results of he-pycnometry measurements. sample id ρskeletal [g/cm3] ρbulk [g/cm3] φhe [%] s-01 2.6591±0.0072 2.259±0.013 15.06±0.71 s-02 2.6524±0.0043 2.296±0.012 13.43±0.45 s-03* 2.6573* 2.433* 10.16* *remark: only two samples were measured the adsorption isotherms of the samples can be classified in the type ii iupac (international union of pure and applied chemistry) class, which is related to macroporous materials (figu re 10). hysteresis was observed on all isotherms. the shape of the hysteresis loop is similar with h3 type according to the iupac classification. the h3 loop is often associated with type ii isotherms and is related to non-rigid aggregates of plate-like materials (thommes, 2015). in addition, macropores that are not completely filled with pore condensate also caused such a hysteresis loop. the main pore throat size is between 75-110 nm according to the mercury porosimetry measurements. calculated hg-porosity (φhg) values are lower than the heporosity values (φhe) indicating micropores (< 2 nm pore diameter) in the pore structure. besides, the sbet values are also higher than shg which also suggests the presence of micropores (table 3). table 3. test results of pore structure investigations. sample id physisorption hg-porosimetry n2 co2 sbet [m2/g] vtot [cm3/g] vmic [cm3/g] smic [m2/g] shg [m2/g] psdmax [μm] s-01 7.74 4.26e-02 2.82e-03 8.10 4.66 9.33e-02 s-02 5.60 3.38e-02 2.04e-03 5.84 4.24 7.79e-02 s-03 7.61 3.99e-02 2.93e-03 8.40 4.76 1.09e-01 6. conclusions a detailed petrophysical investigation was performed on 3 plugtriplets drilled from the tótkomlós calcareous marl section, in­ cluding acoustic anisotropy and complex pore structure characterization. using the multicore test method, acoustic wave velocities were measured at different confining pressures. based on accurate velocity measurements on plugs with different orientations, ani­ sotropy could be described in a quantitative way. these parameters could be applied in seismic depth migration. porosity measure­ ments showed porosity reduction as a function of increasing effec­ tive stress. pore structure investigations indicated plate-like mate­ rials with a typical pore throat size between 75-110 nm. micro pores (< 2 nm pore diameter) were also observed in the pore space. in conclusion, self-sealing in marl could be observed during the measurements. ppd permeability measurements under reservoir conditions parallel with ultrasonic velocity measurements would help to track and understand the process and hence petro­ physically characterize marls of sedimentary basins. references akaike, h. (1973): information theory and an extension of the maximum likelihood principle.– in: petrov, b.n. & csaki, f. (eds.): second international sympo­ sium on information theory. academiai kiado, budapest, 267–281. american petroleum institute (1998): recommended practices for core analysis – api publishing services, washington. auld, b.a. (1973): acoustic fields and waves in solids.– john wiley & sons inc, new york, 423 p. cazorla-amoros, d., alcaniz-monje, j. & linares-solano, a. (1996): characterization of activated carbon fibers by co2 adsorption.– langmuir, 12. 2820–2824. doi: 10.1021/la960022s cholach, p.y. & schmitt, d.r. (2006): intrinsic elasticity of a textured transverse­ ly isotropic muscovite aggregate: comparisons to the seismic anisotropy of schists and shales.– journal of geophysical. research, 111, 410–427. doi: 10.1029/2005jb004158 dellinger, j. & vernik, l. (1994): do traveltimes in pulse-transmission experi­ ments yield anisotropic group or phase velocities?– geophysics, 59, 1774–1779. doi: 10.1190/1.1443564 fedor, f., hámos, g., jobbik, a., máthé, z., somodi, g. & szűcs, i. (2008): laboratory pressure pulse decay permea laboratory pressure pulse decay perme­ ability measurement of boda claystone, mecsek mts, sw hungary.– physics and chemistry of the earth, 33, s45–s53. hemsing, d.b. (2007): laboratory determination of seismic anisotropy in sedimen­ tary rock from the western canadian sedimentary basin: m.sc. thesis, university of alberta. hornby, b.e. (1998): experimental laboratory determination of the dynamic elastic properties of wet, drained shales.– journal of geophysical. research, 103, 29945–29964. doi: 10.1029/97jb02380 johnston, j.e. & christensen, n.i. (1995): seismic anisotropy of shales.– jour­ nal of geophysical. research, 100, 5991–6003. doi: 10.1029/95jb00031 juhász, gy. (1992): a pannóniai (s.l.) formációk térképezése az alföldön: elterjedés, fácies és üledékes környezet [pannonian (s.l.) lithostratigraphic units in the great hungarian plain: distribution, facies and sedimentary environment – in hungar­ ian].– földtani közlöny, 122/2–4, 133–165. juhász, gy. (1998): a magyarországi neogén mélymedencék pannóniai képződményeinek litosztratigráfiája [litostratigraphy of pannonian formations of hungarian neogene basins – in hungarian].– in: jámbor et al.: magyarország geológiai képződményeinek rétegtana, budapest, 469–483. koroncz, p. & fedor, f. (2016): experimental investigation of stress-dependent petrophysical behaviour of reservoir rocks.– in: cvetković et al. (eds.): 8th croatian-hungarian and 19th hungarian geomathematical congress, trakošćan, 83–87. lemberkovics, v. (2016): distribution and heterogeneity of tótkomlós calcareous marl member of endrőd marl formation, kiskunhalas & kelebia exploration areas – mészmárga ankét, szolnok – verbal presentation, 11 slides. magyar, i., juhász, gy., szurominé korecz, a. & sütőné szentai, m. (2004): a pannóniai tótkomlósi mészmárga tagozat kifejlődése és kora a batton­ ya-pusztaföldvári-hátság környezetében [the tótkomlós calcareous marl member of the lake pannon sedimentary sequence in the battonya-pusztaföldvár region, se hungary – in hungarian].– földtani közlöny, 133/4, 521–540. magyar, i., radivojević, d., sztanó, o., synak, r., ujszászi, l. & póc­ sik, m. (2013): progradation of the paleo-danube shelf margin across the pan­ nonian basin during the late miocene and early pliocene.– global and planetary change, 103, 168–173. doi: 10.1016/j.gloplacha.2012.06.007 martínez, j.m. & schmitt, d. (2011): investigating anisotropy in rocks by using pulse transmission method.– canadian society of exploration geophysicists re­ corder, 36/10, 38–43. martínez, j.m., schmitt, d.r. & kofman, r. (2012): anisotropy measurements in a multi-faced core sample by using pulse transmission method, geoconvention, calgary, alberta. ostadhassan, m., zeng, z., jabbari, h. (2012): anisotropy analysis in shale using advanced sonic data – extended abstract, bakken case study, aapg an­ nual convention and exhibition, usa. thommes, m., kaneko, k., neimark, a.v., olivier, j.p., rodriguez-rei­ noso, f., rouquerol, j. & sing, k.s.w. (2015): physisorption of gases, with special reference to the evaluation of surface area and pore size distribution (iupac technical report).– pure and applied chemistry, 87, 9–10, 1051–1069. doi: 10.1515/pac-2014-1117 thomsen, l. (1986): weak elastic anisotropy.– geophysics, 51, 1954–1966. doi:10.1190/1.1442051 tsvankin, i. (1997): reflection move-out and parameter estimation for horizontal transverse isotropy.– geophysics, 62, 614–629. doi: 10.1190/1.1444170 vernik, l. & liu, x. (1997): velocity anisotropy in shales: a petrophysical study.– geophysics, 62, 521–532. doi: 10.1190/1.1444162 2019 | 72 / special issue | 127–143 | 12 figs. | 3 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society article history: manuscript received april 23, 2019 revised manuscript accepted july 17, 2019 available online december 20, 2019 keywords: quartz vein type gold deposit, fluid inclusion, δdh2o and δ18oh2o, fluid immiscibility, fancha, henan province 1. introduction the xiaoqinling gold deposit area is an important rock gold producing areas in china (chen et al., 1998; fan et al., 2000a; mao et al., 2002; wang et al., 2010). although the area has been the subject of a great deal of investigative research, the way in which the gold deposits formed here is still debated. in xiaoqinling, the primary type of deposit is quartz vein gold of which the fancha gold is a typical example (li et al., 1996; ren, 2012; zhou et al., 2014). research on the fancha gold deposits can therefore, not only potentially identify the metallogenic formation mechanism of such deposits, but also provide critical theoretical support for the mineral exploration of the area. previous studies have investigated the ore-forming fluids of the gold deposits in the area (chen et al., 2007; fan et al., 2003; li et al., 2012b; mao et al., 2002; ). the phases of the inclusions in the current gold deposits are three-phase co2-rich, three-phase co2-bearing, two phase aqueous, liquid, vapours, and threephase daughter mineral-bearing inclusions (zhao et al., 2017; zhou et al., 2015). currently the main theories on the origins of the ore-forming fluids include: (1) metamorphic fluids (wang and zhou, 1996), (2) magmatic fluids (nie et al., 2001), (3) deep mantle fluids (lu et al., 2003), and (4) mixed fluids (chen et al., 2007). regarding the ore fluid evolution, there are generally two theories: (1) magmatic water gradually evolves into meteoric wa ore-forming fluids of the fancha gold deposit, lingbao, henan province zhang yu1*, cao yi2 and li hongmeng2 1 china university of geosciences (beijing), school of ocean sciences, 100083 beijing, p.r.china; (zhangyu_cugb@foxmail.com) 2 china university of geosciences (beijing), school of earth sciences and resources, 100083 beijing, p.r.china doi: 10.4154/gc.2019.22 abstract the fancha gold deposit is a representative of the auriferous quartz vein type gold deposits in the xiaoqingling gold district where the ore-forming fluid is one of the key controlling factors in the deposits formation, and also the main focus of ore deposit research. here, the geological characteristics and fluid inclusions of the fancha deposit are presented in detail, with a description of the potential origin and evolution of the fluid and the genesis of the deposit. field investigation and petrographic observation show that ore-bodies in the fancha deposit are preferentially hosted in the amphibolites of the taihua group and are controlled by brittle fracture. hydrothermal alteration in the fancha deposit includes silicification, potash feldspathization, sericitization, pyritization and carbonatization. the mineral assemblage, cross-cutting and replacement relationships indicate that the ore-forming process can be divided into quartz-k-feldspar (i), quartz-coarse pyrite (ii), quartz-fine pyrite (iii), quartz-polymetallic sulfide (iv) and carbonate stages (v). gold is mainly precipitated in stages iii and iv. three types of fluid inclusions have been identified in the fancha deposit, based on their characteristics at room temperature: three-phase co2-rich, three-phase co2-bearing and two-phase aqueous inclusions. the fluid inclusions demonstrate the modes of homogenization temperatures of 363.3°c, 325.5°c, 273°c, 258.62°c and salinities of 14.53, 9.59, 11.61, 8.03 wt% nacl.equiv., for stages ii, iii, iv, and v respectively. the ore-forming fluid in the fancha deposit belonged to the co2-h2o-nacl-(±ch4) fluid system with mid-low temperature and mid-low salinity. the δ18oh2o of the metallogenic fluids was between 1.36 and 6.28, and the δdh2o was between -87 and -53.1. hydrogen and oxygen isotope data indicate that the ore-forming fluids were dominated by metamorphic fluids in the early stage, and that the metamorphic fluid gradually mixed with circulating meteoric water during the later stages. petrographic observation and microthermometry suggest that fluid mixing and immiscibility obviously occurred during the main metallogenic stage. fluid mixing and fluid immiscibility probably led to gold deposition in the fancha deposit. ter (fan et al., 2000a; fan et al., 2000b), and (2) metamorphic water gradually evolves into meteoric water (qi et al., 2002). there are also various views on the ore sources from: (1) mesozoic granites (nie et al., 2001; zhao et al., 2017), (2) the taihua group (feng et al., 2014; li et al., 1996), (3) mainly the centrosphere, and a small proportion from the wall rock (lu et al., 2003), and (4) a multi-material source (chen et al., 2007). the placement of basic dykes in xiaoqinling reflects the tectonic setting of the crustal extension. the lithology is mainly diabase and lamprophyre, which are spatially related to the goldbearing quartz vein (chen et al., 2008; luan et al., 1985; zhang et al., 2009a). presently, in terms of the relationship between these two, there is debate: li et al. (1996) considered that the basic dykes provide a material source for gold mineralization, while chen et al. (1998), li et al. (2012a), li et al. (2012b) challenged this theory. in addition, some scholars believe that the volatiles in the lamprophye mainly act as mineralizers (ni, 1994). fluid inclusions can preserve various geological and geochemical information during mineralization. therefore, conducting a detailed physico-chemical and thermodynamic study of fluid inclusions can yield important data on the mineralization process, which may also inform and guide prospecting and exploration (lu, 2004; melfos et al., 2016; roedder, 1984; tasev et al., 2018). therefore, our main objective focused on studying the fancha gold deposits, and in particular, thoroughly g eo lo gi a c ro at ic a geologia croatica 72 / special issue128 investigating the geology, fluid inclusions and their stable isotope geochemistry. furthermore, we explored the metallogenic mechanism by tracking the source of the ore-forming fluids and analyzing the fluid evolution. 2. regional geology the xiaoqinling area is located at the northern margin of the eastern qinling orogenic belt (mao et al., 2010; wang et al., 2008). the east side of this area begins in the zhuyang basin in henan and ends 50km away in the west at shanxi huashan. the southern boundary is the xiaohe fault, and to the north, the taiyao fault. the area is 7 to 15km wide, and overall it appears as an irregular strip (fig. 1). the emergent stratum of this area is the taihua group (luan et al., 1990), which in accordance with other studies is divided into an upper and a lower basement. the upper basement is further sub-divided, from bottom to top, into the guanyintang formation and the huanchiyu formation (xu et al., 2009). the guanyintang formation is dominated by biotiteplagiogneiss and plagioclase amphibole gneiss, while the huanchiyu formation is composed of mainly marble and diopside marble. the lower basement comprises three units; from bottom to top they are the basic supracrustal rock, the yangzhaiyu formation, and the sifangou formation (feng et al., 2014). the supracrustal rock is mainly composed of amphibolites and plagioclase amphibole gneiss, most of which is in the form of inclusions in metamorphic granite. the yangzhaiyu formation is dominated by biotite-plagiogneiss and plagioclase amphibole gneiss while the sifangou formation is mainly biotite plagiogneiss and biotite monzogneiss. in terms of construction and development, the region’s major fold structures are the wuli village anticline, qishuping syncline and the laoyacha anticline (luan and chen, 1990; mao et al., 2005). the fault structures consist mainly of the approximately e-w trending axial folds, and the similarly trending e-w and nearly s-n trending faults. more than 500 ductile-brittle faults have been discovered in the area (hu et al., 2005; mao et al., 2005), mostly trending e-w (zhang et al., 2009b). from the regional perspective, the e-w trending faults are the main ore-controlling structures. the south directed faults of the middle ore belt and the north directed faults of the northern ore belt are the main ore-controlling structures of large and medium-sized gold deposits in the region, striking several kilometres. both the ductile shear zone and the brittle shear zone were found to contain gold-bearing quartz veins. the magmatic rocks in the area include palaeoproterozoic granites, early mesozoic granites and late mesozoic granites (gao et al., 2012; wang et al., 2010). among them, the palaeoproterozoic granites are mainly the xiaohe and guijiayu rock masses. from east to west, the mesozoic granites contain the niangniangshan, wenyu and huashan rock masses. in addition, most gold deposits in the region developed into palaeoproterozoic and late mesozoic mafic dykes, with the gold-bearing quartz veins existed as a symbiotic or mutual cross-cutting complex. the lithology is mainly diabase and lamprophyre, and the lamprophyre consisted of mainly camptonite and kersantite (ni, 1994; wang et al., 2008; wang et al., 2010). 3. geology the administrative division of the fancha gold mining area belongs to zhuyang town, lingbao city, henan province. the excavation strata in the mining area consist mainly of supracrustal rock (ar3b), the yangzhaiyu (ar3yn), sifangou (ar3sf ), and guanyintang formations (ar3g) in the taihua group. magmatic figure 1. map of the research area. a) tectonic subdivisions of china (modified from liu et al., 2015) cco: central china orogen; b) tectonic subdivisions of the qinling orogen. (modified from zhou et al., 2015); c) geological map of the xiaoqinling gold belt (modified from zhou et al., 2015). g eologia c roatica yu et al.: ore-forming fluids of the fancha gold deposit, lingbao, henan province 129 rocks exposed in the mining area include diabase porphyrite, monzonitic granite and granitic pegmatite (fig. 2) (gao et al., 2012; ni, 1994; wang et al., 2008; wang et al., 2010). diabase porphyrite is gray-green, with a blastoporphyritic texture, blocky structure and strong sericite alteration. it is widely distributed in the eastern mining area, mainly intruded in an approximately n-s orientation, and partially intruded as e-w trending veins. monzonitic granite is medium-fine grained, has a blocky structure, and is composed mainly of plagioclase, k-feldspar, quartz, biotite, a small amount of amphibole, and magnetite. it is distributed in the centre of the mining area. granitic pegmatite is grayish white, with a blocky structure. it is composed of microcline, plagioclase, quartz, and biotite and located in the southeast of the mining area. the mining area mainly developed near e-w trending ductile-brittle faults. the faults are divided into compression-torsional and tensile faults, according to their mechanical properties. the compression-torsional faults are the ore-controlling structure, and the tensile faults have a destructive effect on the ore body. the mining area is located in the eastern tip of the xiaoqinling anticline, and the anticline trends e-w with a vertical axial plane (chen, 2013; ren, 2012). 3.1. characteristics of the ore body the fancha gold deposit consists of four gold veins s902, s431, s310 and s301. this study is focused on the s902 vein (fig. 2). the wall rocks of the s902 vein are mainly composed of striped migmatite, palaeoproterozoic granites and plagioclase amphibole gneiss of the taihua group. the ore body is controlled by nne brittle faults and its maximum depth is c. 710m.the ore body strikes 280° in a sw direction, with an inclination angle of c. 40 °, an average vein thickness of 0.50m, and a plate-like or evenly veined profile (ren, 2012). 3.2. ore characteristics the ore minerals are pyrite, chalcopyrite, sphalerite, galena, and a small amount of natural gold. the ores are mainly quartz, kfeldspar, sericite and carbonate. paragenetic sequences of different ore stages with corresponding mineral assemblage are shown in fig. 3i. 3.2.1. the main ore minerals pyrite is grayish yellow or light yellow and distributed throughout the entire mineralization process. grain size varies greatly, mostly as fine particles but a small amount exhibits a visible cubic crystalline form. it often occurs as agglomerate with fine veins, or sparsely disseminated in quartz veins or mineralized altered rocks. in the early stage of mineralization, it is mostly a coarse pyrite euhedral-semi-shaped structure, with a disseminated or blocky structure in milky quartz (fig. 3a,b). cracks often occur at this stage, and the fissures can contain a small amount of gold (lu et al., 2013). during the main mineralization stage, the pyrite is mostly of medium-fine subhedral-allotriomorphic granular form, co-existing with the quartz and various metal sulfides (fig. 3c,d). the pyrite appears as disseminated veinlets and lumps distributed on the side of the quartz vein or in the micro-cracks of the rock, usually with a higher gold content. at the late stage of mineralization, pyrite is generally fine subhedralallotriomorphic granular in form, distributed in carbonate veins or altered rocks and is associated with carbonate minerals such as calcite (fig. 3e). the gold content is low. gold content is general ly figure 2. geological sketch map of the fancha gold deposit and geological cross section along the no.2 exploration line (modified from ren, 2012). g eo lo gi a c ro at ic a geologia croatica 72 / special issue130 positively correlated with the pyrite content in quartz veins or mineralized altered rocks. chalcopyrite is bright yellow, with a metallic lustre, and is fractured shell-like, and irregularly granular in shape (figs. 3d,f). usually it is found in quartz fine-grain pyrite and quartz polymetallic sulfide stages. it forms as an agglomerate, disseminated or fine veins and is produced in quartz vein fissures or altered rocks, commonly associated with other sulfides. galena is mid gray with a metallic lustre, and occurs mainly in quartz veins. it is very unevenly distributed, with most at the figure 3. the main ore types and paragenetic sequences of different ore stages with corresponding mineral assemblages of the fancha gold deposit. a) sparsely disseminated coarse pyrite in quartz; b) cataclastic coarse pyrite and fine-grained pyrite in quartz; c) fine-grained pyrite and chalcopyrite in smoky gray quartz; d) chalcopyrite encrusts fine-grained pyrite in quartz; e) veinlet pyrite + chalcopyrite + sphalerite + galena in quartz; f ) quartz + pyrite + chalcopyrite + galena in quartz-polymetallic sulfide stage; g) potassium feldspar in early stage cut by quartz coarse-grained veins; h) quartz and calcite at the end of mineralization; i) paragenetic sequences of different ore stages with corresponding mineral assemblages. q-quartz; py-pyrite; ccp-chalcopyrite; sp-sphalerite; cal-calcite; gn-galena; kf-k-feldspar. g eologia c roatica yu et al.: ore-forming fluids of the fancha gold deposit, lingbao, henan province 131 polymetallic sulfide stage. it occurs in veinlets or as mass distribution with a euhedral-hypidiomorphic granular structure (fig. 3e, f). a small amount is fine-grained. it is combined with pyrite, chalcopyrite, sphalerite and quartz as minerals, and is closely related to gold enrichment. sphalerite is bright silver gray, with a metallic lustre, medium-fine grained structure, and is mostly associated with the quartz polymetallic sulphide stage. it is mainly observed in association with galena and net veins, as agglomerations and is distributed in quartz veins (fig. 3e). 3.2.2. main gangue minerals quartz is the most important gangue mineral in the ore (usually > 90%), and generally occurs in different-sized veins discontinuously distributed in the cracks. in the coarse-grained pyrite stage of mineralization, quartz is a milky white dense block assembly, often forming thick veins (fig. 3a). during the fine pyrite phase, it is the colour of cigarette ash with a fine granular structure, often co-existing with pyrite and chalcopyrite (fig. 3c). it is mainly distributed in fine vein quartz at micro-cracks in the veins and is slightly more transparent during this phase. at the polymetallic sulphide stage, quartz is generally colourless, transparent, translucent, and euhedral or subhedral, co-existing with polymetallic sulphides (fig.3e). it is distributed in the early stage quartz veins. at the carbonate stage, the quartz is white and granular and associated with calcite (dolomite) and pyrite. the fine veins or small clumps are scattered at the edges of, or in the altered rocks of the veins (fig. 3g). k-feldspar is pink and belongs to a group of potash altered minerals. it is generally distributed in the form of aggregates, which are produced in large veins or dip-like forms, and often co-exists with quartz. the type of k-feldspar is microcline, and polysynthetic twins and crosshatched twins are visible under the microscope (fig. 3g). sericite forms microscopic scaly aggregates with directional alignment, complete cleavage and a silky lustre. it is closely related to gold mineralization. carbonate is mainly calcite and it is colourless, transparent or translucent, with complete cleavage in both directions and a low degree of crystallization. it forms as irregular veins (fig. 3h) among other surrounding rocks with carbonate minerals and very low levels of mineralization. through detailed ocular and microscopic observation, it can be concluded that the fancha gold ore includes the following structures: euhedral or subhedral-granular, allotriomorphic granular including, cataclastic and filling structure with a metasomatic texture. the fancha gold is mainly a vein-like, disseminated, and agglomerate structure. 3.3. wall rock alteration the common surrounding rock alterations in the mining area include silicification, beresitization, potash feldspathization, chloritization, epidotization and carbonation. rock alteration in the area is not strong, and all kinds of alterations are distributed at the boundary of the contact zone between the gold-bearing quartz vein and wall rocks, showing characteristics of linear alteration. silicide is the most widely developed alteration in the fancha gold deposit, and it is disseminated in wall rocks within the fault zone as lumps and mesh-vein by metasomatism and infilling. the hydrothermal fluid is relatively well developed in the early and middle stages, and rare in the later stage. the lithology of beresitization is accompanied by mineralization, and densely disseminated as lumps and fine veins. it is particularly well developed in the early and middle stages of hydrothermal alteration and is closely associated with mineralization. potash feldspathization often occurs in the early stage of mineralization, is spread in the distal rocks in disseminated or veined forms, and is occasionally observed in the adjacent wall rock. chloritization and epidotization is evidenced by a pale green colour and is distributed in the wall rock in clumped and disseminated forms, and is not closely related to mineralization. carbonation is formed in the late stage of mineralization with mainly fine veins, usually of quartz carbonate. the main minerals are calcite, dolomite and ferro-dolomite. 3.4. metallogenic stage based on comprehensive field and laboratory study, the fancha gold deposit mineralization process can be divided into five stages recognised by different mineral assemblages (fig. 4). quartz-k-feldspar stage (i): early potassium-rich fluid migrated along the fractured zones and reacted (water-rock) with the roof and floor of the wall rocks, forming a strong planar massive potassic alteration. this stage is the preparatory stage of mineralization. quartz coarse pyrite stage (ⅱ): ore-bearing hydrothermal fluids filled fractures of the wall rock appearing as large milky quartz veins and the ore is a coarse-grained pyrite type. the pyrite is bright yellow, and generally occurs as medium-coarse cubes or pentagonal dodecahedron with a good degree of euhedral form. quartz fine-grain pyrite stage (ⅲ): this stage is the main mineralization stage. the ore-forming hydrothermal fluids penetrate into the large quartz vein fractures of the early stage as fine veins, characterized by fine-grained pyrite and smoky quartz. it is accompanied by a small amount of allotriomorphic chalcopyrite deposition. quartz-polymetallic sulfide stage (ⅳ): the ore-bearing hydrothermal fluids continue to fill the quartz vein fractures and are enriched in the local area by metasomatism. sulphide ores disseminated by veinlets are typically present in this stage. the main metallic mineral assemblage is pyrite, chalcopyrite, galena, sphalerite and gold. the gangue minerals are smoky quartz, with a granular texture. a small amount of sericite is developed in the fractures. quartz carbonate stage (v): the last stage of mineralization with no gold mineralization. the plagioclase amphibole gneiss is mainly filled with carbonate veins (calcite, dolomite), and in open space, the carbonate mineral precipitated as crystal clusters with the quartz. 4. fluid characteristics 4.1. samples and analytical methods all the samples were collected from the s902 vein in the fancha gold deposit. based on the different mineralization stages, we collected 5 samples at each stage for further study (table 1). the samples were processed by the hebei institute of geology and mineral resources survey laboratory into 10 inclusion sections. micro thermometric measurements were performed using a linkammdsg600 heating-freezing stage attached to a leitz ortholux transmitted light microscope connected to a television camera and screen. the stage was calibrated using synthetic fluid inclusions. the estimated accuracy was ±0.1 ℃ at temperatures below 30 ℃ and ±1 ℃ at temperatures above 30 ℃. the warmg eo lo gi a c ro at ic a geologia croatica 72 / special issue132 ing rate was maintained at 0.2 to 5 ℃ per minute, and the heating rate was reduced to 0.2 ℃ per minute when close to phase-change conditions. freezing experiments were performed first on all sections to avoid inclusion decrepitation. the measured phase transitions included the melting temperature of ice (tm-ice), the melting temperature of solid co2 (tm-co2), the temperature of co2-clathrate dissociation (tm-cl), the homogenization temperature of co2 (th-co2), and the total homogenization temperature (th). salinities were calculated using the equations of bodnar (1993) for aqueous fluids and collins (1979) for aqueous-carbonic fluids. six samples were collected for each metallogenic stage. as we failed to collect suitable carbonate samples at the carbonate stage and it is not the main research focus, we did not investigate figure 4. characteristics of the different types of mineralization of the fancha gold deposit. a1) a3) photographs of stage i, potassium feldspar vein cut by quartz coarse-grained pyrite vein in hand specimen; b1) b3) photographs of stage ii, massive or sparsely disseminated coarse pyrite in milky white quartz, and the completely filled fractures of the wall rock as veins; c1) c3) photographs of stage iii, smoky gray quartz fine-grained pyrite veins of stage iii are filled in milky white quartz fractures of stage ii; d1) d3) photographs of stage iv, polymetallic sulfide veins fill in the fractures of milky white quartz; e1) e3) photographs of stage v, polymetallic sulfide veins cut by carbonate veins. q-quartz; kf-k-feldspar; py-pyrite; ccpchalcopyrite; gngalena; cal-calcite. g eologia c roatica yu et al.: ore-forming fluids of the fancha gold deposit, lingbao, henan province 133 it further. the oxygen and hydrogen isotopes were analyzed on a finnigan mat253 mass spectrometer in the analytical laboratory, beijing research institute of uranium geology, using the methods outlined by ding (1980). oxygen gas was generated from the samples by a quantitative reaction with brf5 in externally heated nickel vessels. hydrogen in the extracted water from the fluid inclusions within the quartz separates was replaced by zinc at c. 600 ℃ and released for mass spectrometry. the isotope data are reported in ppm relative to the vienna smow standard for oxygen and hydrogen. total uncertainties were estimated to be better than ±0.2‰ for δ18o and ±1‰ for δd. the oxygen isotope ratios of water in equilibrium with the minerals are calculated using the fractionation formula reported by clayton et al. (1972). 4.2. types of fluid inclusions 4.2.1. genetic types based on their genesis, fluid inclusions of the fancha gold deposit are classified as primary, secondary and pseudo secondary inclusions (lu, 2004). isolated primary inclusions of suborbicular or oval shape with a diameter of 5~40μm often have a discrete distribution (fig. 5a) and are occasionally observed along the growth zoning of quartz (fig. 5b). linear secondary inclusions are often distributed in micro-cracks cutting through the boundary of quartz crystals, with a elongate but irregular in shape and irregular shape (fig. 5c, d). however, since they cannot represent ore fluid, they are not discussed further. pseudo secondary inclusions, with compositions consistent with the primary inclusions, are elongate and formed as linear groups distributed within quartz micro-cracks during crystal growth and represent the oreforming fluids. 4.2.2. phase types petrographic observations indicated that the fluid inclusions of the fancha gold deposit have 3 main phases: three-phase co2bearing inclusions (vco2 + lco2 + lh2o, lh2o > 50%), threephase co2-rich inclusions (vco2+lco2+lh2o, lh2o<50%) and two-phase aqueous inclusions (lh2o+vh2o). occasionally there are also vapour inclusions (vco2 or vh2o) and liquid inclusions (lco2 or lh2o). three-phase co2-bearing inclusions consisted of brine solution, vco2 and lco2. these inclusions are widely distributed throughout the entire process of mineralization, representing the main inclusion type of the fancha gold deposit. the vco2+ lco2 phase accounts for about 15 50% of the inclusion volume, and the ratio of vco2 and lco2 is approximately 5 35%. such inclusions are often suborbicular, irregularly-shaped, or negative crystalline with a diameter of 10 to 40μm (fig. 6a1-a3). three-phase co2-rich inclusions consisted of brine solution, vco2 and lco2. these inclusions are mainly found in the polymetallic sulfide stage, and rarely in other mineralization stages. the volume of vco2 + lco2 accounts for c. 50 – 80% of the total volu me. the ratios of vco2 and lco2 are approximately 5 – 15%. inclusions often are suborbicular or oval, and columnar crystalline or negative crystalline. compared with the size of the threephase co2-bearing inclusions, they have a slightly smaller diameter of usually 5 – 25μm (fig. 6b1-b3). two-phase aqueous inclusions are comprised of lh2o and vh2o. the vapour-liquid ratio is less than 15%, and they are often elongated and suborbicular, with a diameter mostly less than 20μm (fig. 6c1-c2). vapour inclusions develop in all stages, showing vapourphase at room temperature with no liquid and no significant change with increasing and decreasing temperature. they are dark black, mostly suborbicular, short cylindrical and regular shapes, with a typical diameter of 5–15μm (fig. 6e2). liquid inclusions at room temperature, are only a single liqu id phase (lh2o) with no vapour phase and do not change with changes in temperature. there are only a few of this type of infigure 5. genetic types of fluid inclusions in the fancha deposit. a) isolated primary inclusions in single quartz; b) a group of primary inclusions distributed along the growth zoning of quartz; c) linear secondary inclusions traverse crystals; d) linear secondary inclusions along cracks of crystal. g eo lo gi a c ro at ic a geologia croatica 72 / special issue134 clusion, they are colourless, transparent and filled with aqueous solution. the general size is 5 – 10μm, mainly formed in the late stages of mineralization (fig. 6e1, e3). in addition, microscopic observation showed that daughter mineral-bearing inclusions are found in the polymetallic sulphide stage (fig. 6d). however, due to their rarity, they were ignored. there are a few pure lco2 inclusions, mainly found in the metallogenic stage. vco2 occurs during cooling to below 20 °c. the possible mechanism is that the original homogeneous fluid is subjected to structural decompression or mixed with meteoric water to cause fluid boiling, so a large amount of vapour escapes and the mineral captures the inclusion. there are many “bottle-neck” shapes in the sample, probably because these inclusions have been subjected to local stress effects associated with the primary mineral after crystallization. it is noteworthy that different types (or one type with various ratios of phases) of inclusions are present in the field during the main mineralization stage, suggesting the possibility of fluid immiscibility with the ore-forming fluid (lu, 2004; roedder, 1984). 4.3. fluid inclusion assemblage the concept of the fluid inclusion assemblage (fia) was proposed by touret (2001) and goldstein (2001). fia represents a set of the representative period inclusions captured in a certain stage. all inclusions of a fia have similar features and they should have a substantially similar homogenization temperature (the difference does not exceed 15 ℃). however, due to frequent tectonic activity in the xiaoqinling area, the mineralization and geological complexity means that the same fia inclusions have a slight temperature variation. the reason for this is that after being captured, the inclusions suffered varying degrees of destruction and transformation (stretching or partially open), with stretching typically resulting in a high temperature (chi et al., 2008). therefore, if the temperature difference of the inclusions in one fia is within a 20–25℃ range, it is still considered that the inclusion thermometry data are valid. robust data was not obtained for potash feldspathization (stage i) so it was excluded from further study. the distribution of inclusions and the inclusion characteristics of each mineralization stage are shown in fig. 7. figure 6. phase types of fluid inclusions in the fancha deposit. a1) a2) three-phase co2-bearing inclusions; b1) b3) three-phase co2-rich inclusions; c1) c2) twophase aqueous inclusions; d) three-phase daughter mineral-bearing inclusion; e1) aqueous inclusion; e2) vapour inclusions (co2); e3) liquid inclusion (co2). g eologia c roatica yu et al.: ore-forming fluids of the fancha gold deposit, lingbao, henan province 135 quartz coarse-pyrite stage (ⅱ): the main inclusions are three-phase co2-bearing inclusions, accounting for c. 70 percent of the total number of inclusions. inclusions are distributed as large strips and large planar forms, as well as visible strips and linear discrete shapes. their abundance can reach 80%, they have a large volume, and range from 15 to 40 μm in diameter. they are usually negatively crystalline, suborbicular, nearly elliptical and elliptical. the filling degree generally varies from 50% to 80% (fig. 7a1-a2). a few three-phase co2-rich inclusions were also discovered. quartz fine-grain pyrite stage (ⅲ): mainly composed of three-phase co2-bearing inclusions (60%), some three-phase co2-rich inclusions (30%) and a few two-phase aqueous inclusions (10%) (fig. 7b1-b3). primary inclusions are distributed in discrete isolates, partially banded and occurring in groups. inclusion size is smaller than at stage (ⅱ), 10–25μm in diameter. shape morphology is suborbicular, elliptical or irregular. the fill degree is 40% to 60%. polymetallic sulphide stage (ⅳ): three-phase mainly co2rich inclusions (95%), two-phase liquid-rich inclusions (5%), very small amounts of pure liquid phase (lco2) inclusions, and occasionally some three-phase daughter mineral-bearing inclusions (fig. 7c1-c3). the inclusions are disordered, distributed in groups, and mostly a primary isolated shape. the abundance of the inclusions decreased slightly in comparison with the earlier stages, and the primary inclusions were negative crystalline, and suborbicular, or elliptical. inclusion diameter is 5–20μm, with generally less than 50% infill. carbonate stage (ⅴ): mainly two-phase liquid-rich inclusions (40%), three-phase co2-bearing inclusions (35%) and a few three-phase co2-rich inclusions. the inclusions are sparse, disordered and discretely distributed. occasionally, small-area clusters are distributed in a strip. the number of inclusions is small, and nearly circular, elliptical, negative crystal, pointed, or a regular shape. the inclusion volume is small, with a diameter generally from 5–10μm. the fill degree is 20%–80% (fig. 7d1-d3). figure 7. characteristics of fia in quartz in different stages of mineralization. a1) a2) threephase co2-bearing and three-phase co2-rich inclusions in stage ii; b1) b3) three-phase co2-bearing inclusions, three-phase co2-rich and two-phase aqueous inclusions in stage iii; c1)-c3) three-phase co2-rich inclusions and two-phase aqueous inclusions in stage iv; d1) d3) twophase aqueous, three-phase co2-rich and three phase co2-bearing inclusions in stage v. g eo lo gi a c ro at ic a geologia croatica 72 / special issue136 4.4. homogenization temperature, salinity and density the microscopic temperature measurement data of fluid inclusions in each metallogenic stage in the fancha gold deposit can be described as follows (table 2). quartz coarse-pyrite stage (ⅱ): the homogenization temperature of three-phase co2-rich inclusions is 255.4–315.1℃, with a mean of 277.5 ℃, equalizing to a homogeneous vapour phase. the homogenization temperature of three-phase co2bearing inclusions is 261.4–363.3 ℃, with a mean of 293.1℃, equalizing to a homogeneous liquid phase. the melting temperature of the solid-phase co2 is -60.0–-56.7℃, which is below the melting temperature of pure co2 in the solid phase (-56.6 ℃). this indicates that in addition to co2 inclusions, the vapour may also contain other ingredients (e.g., ch4). the melting temperature of co2 clathrate in the three-phase co2-rich inclusion is 3.0–6.5℃. the salinity was determined from a temperature – salinity table for co2 clathrate melting (collins, 1979). the salinity is 6.54 – 11.89 wt% nacl equiv., with an average of 9.24 wt% nacl equiv. the co2 clathrates of threephase co2 bearing inclusion has a melting temperature of 0.9 to 7.0 ° c. the salinity varies from 5.68 to 14.53 wt% nacl equiv., with an average of 9.63 wt% nacl equiv. the homogenization temperature of the co2 part is 25.0 – 31.0℃. according to the known relationship between the homogenization temperature of each part and the co2 phase density, the relative density of the co2 phase was calculated as c. 0.70–0.80g/cm3. quartz fine-pyrite phase (ⅲ): the homogenization temperature of three-phase co2-rich inclusions is 235.2–325.5℃, with a mean of 275.7℃, equalizing to a homogeneous vapour phase. the homogenization temperature of three-phase co2bearing inclusions is 258.5–310.3 ℃, with an average of 288.1℃, equalizing to a homogeneous liquid phase. the melting temperature of the solid-phase co2 is -60.0–56.7℃, which is below the melting temperature of pure co2 in the solid phase (-56.6 ℃). for co2 clathrate of three-phase co2-rich inclusion, the melting temperature is 4.6 – 8.4℃. salinity is 3.15 – 9.59 wt% nacl equiv., with an average of 6.44 wt% nacl equiv. the co2 clathrates of three-phase co2 bearing inclusion has a melting temperature of 5.7 to 8.7 ℃. the salinity is from 2.58 to 7.87 wt% nacl equiv., (average 6.47 wt% nacl equiv.). the homogenization temperature of the co2 part is 13.6 – 30.8℃. according to the known relationship between the homogenization temperature of each part and the co2 phase density, the relative density of the co2 phase was calculated as c. 0.60–0.82g/cm3. some measured data for the two-phase aqueous inclusions was also obtained. the complete homogenization temperature is 182.0 – 240.9℃, (mean of 206.7 ℃). the freezing point ranges from -5.6 to -1.2 ℃. the corresponding salinity is 2.07–8.86 wt% nacl equiv., (mean of 4.59 wt% nacl equiv), from the table in bodnar, (1993). polymetallic sulfide stage (iv): the homogenization temperature of the three-phase co2-rich inclusions varies from 203 – 273 ℃, (mean 245.2 ℃), equalizing to a homogeneous vapour phase. for clathrates with a different phase ratio, they have a similar homogenization temperature. the solid co2 melting temperature varies from -59.1 to -56.5 c; co2 clathrate melting temperature is 3.2–7.2℃. and the corresponding salinity is 5.33 to 11.61 wt% nacl equiv., (average 8.79 wt% nacl equiv.). the partable 1. characteristics of fluid inclusion samples in different stages. sample stage host mineral description location fx013 i quartz quartz coarse-grained pyrite fine vein cutting k-feldspar adit1100 fx037 ii quartz quartz coarse-grained pyrite veins in wall rocks 3w10, adit1050 fx016 iii quartz smoky quartz vein with fine-grained pyrite filling in the fractures of milky quartz 6e18, adit1020 fx028 iv quartz fine-grained densely disseminated polymetallic sulphide ore w9, adit1050 fx038 v quartz a small amount of calcite on the quartz in the late stage 6e16, adit1020 table 2. summary of microthermometric data on fluid inclusions in the fancha gold deposit. stage sample host mineral type content/% tm,icm/°c tm,cla/°c th/°c average th/°c ω(nacl)/% average salinity ω(nacl)/% homogenization ii fx037 quartz three-phase co2-rich 30 3.0~6.5 255.4 ~315.1 277.5 6.54 ~11.89 9.10 vapor three-phase co2-bearing 70 0.9~7.0 261.4 ~363.3 293.1 5.68 ~14.53 9.63 liquid iii fx016 quartz three phase co2-rich 30 4.6~8.4 235.2 ~325.5 275.7 3.15 ~9.59 6.44 vapor three-phase co2-bearing 60 5.7~8.7 258.5 ~310.8 288.1 2.58 ~7.87 6.47 liquid two-phase aqueous 10 -5.6~-1.2 182 ~240.9 206.7 2.07 ~8.86 4.6 liquid iv fx028 quartz three-phase co2-rich 95 3.2~7.2 203 ~273 245.2 5.33 ~11.61 8.79 vapor two-phase aqueous 5 -2.0~-0.7 238.7 ~257.6 245.4 1.23 ~3.39 2.45 liquid v fx038 quartz three-phase co2-rich 40 4.6~8.4 190 ~258.6 216.9 3.15 ~9.59 7.85 vapor three-phase co2-bearing 35 5.6~9.4 201.3 ~243.5 226.1 1.22 ~8.03 5.79 liquid two-phase aqueous 25 -4.8~-1.2 182.4 ~225.6 203.5 2.07 ~7.59 5.78 liquid g eologia c roatica yu et al.: ore-forming fluids of the fancha gold deposit, lingbao, henan province 137 tial homogenization temperature is 6.1– 23.8 ℃, and thus the estimated co2 phase density is c. 0.83–0.97g/cm3. only 3 two-phase aqueous inclusions, which formed in the same stage as three-phase co2-rich inclusions, were measured, and their homogenization temperatures are 257.6 ℃, 238.7 ℃, and 240.0 ℃, with a mean of 245.4 ℃, equalizing to a homogeneous liquid phase. however, at this stage, the homogenization temperature of the three-phase co2-rich inclusions is concentrated between 235 and 265 ℃, with a mean of 245.5 ℃, equalizing to a homogeneous vapour phase. the homogenization temperatures of these two are similar. the freezing point of two-phase aqueous inclusions are -2.0, -0.7 and -1.6 ℃, with estimated salinities of 3.39, 1.23 and 2.74 wt% nacl equiv., with a mean of 7.85 wt% nacl equiv. 4.5. pressure and depth to estimate pressure using inclusion mineralization we measured co2 partial homogenization temperature th with a micro thermometer. then, according to shepherd et al. (1985), the co2 phase density (ρco2) was be determined from a graph of the correlation between homogenization temperature and density. to determine the salinity of the fluid, the co2 clathrate melting temperature tm, cla, co2 is initially measured, followed by measurement of the complete homogenization temperature th of the inclusions. since the salinity largely influences the pressure estimation, and our measured average salinity at various stages of mineralization of the fancha gold deposit is nearly 6 wt% nacl equiv., we utilized the correlation graph listed in schwartz (1989), and checked the xco2-vco2-ρ-th in co2-h2o-nacl inclusion with figure 8. histograms showing homogenization temperature a) and salinity b). g eo lo gi a c ro at ic a geologia croatica 72 / special issue138 6% salinity. the resulting th and ρco2 values were used to obtain the xco2 and vco2. again, utilizing the graph, we determined the minimum trapping pressure of the inclusion. in this paper, we estimated the pressure by directly choosing inclusions with a salinity of 6 wt% nacl equiv. in nearly all stages. from the graph we estimated the pressure in stage (ⅱ) at 120-180mpa; stage (ⅲ), 85-140mpa; and stage (ⅳ), 70-120mpa; a declining trend in oreforming pressure. since in our estimation process, we considered that the ore-forming fluid system is approximated as a co2-h2onacl system, and ignoring the impact of ch4, our estimation may be slightly different from the actual value. however, since the level of ch4 is rather low, its impact on our estimation is probably trivial. as the excavation stratum of the fancha gold deposit is mainly the taihua group, we used a rock density of 2.7 g/cm3 in the lithostatic pressure calculations. the lithostatic pressure depth in the quartz coarse-pyrite stage varies from 4.5 to 6.7 km. in the quartz fine-pyrite stage, it is from 3.5 to 5.2 km, and from 3.5 to 4.0 km in the quartz polymetallic sulphides stage. in general, the depth decreased as mineralization progressed. 4.6. hydrogen and oxygen isotopes hydrogen and oxygen isotope analysis is a reliable method for determining the origin of the mineralising fluid. to determine the ore-forming fluid source of the fancha gold deposit, samples were collected from all stages (except for the carbonate mineralization stage) for hydrogen and oxygen isotope experiments. the oxygen isotopic composition was obtained using the oxygen isotopic fractionation equilibrium of the mineral and water as follows: 1000lnαquartz water =3.38×106t-2 -2.90 (200~500℃) (clayton et al., 1972), where t is the formation temperature of the mineral, which is the average homogenization temperature of the inclusion. the δ18oh2o of metallogenic fluids is between 1.36 and 6.28, and the δdh2o is between -87 and -53.1 (table 3). from stage ⅰ to stage ⅳ, the δdh2o initially declined and then gradually rose. 5. discussion 5.1. diagenesis and mineralization age using multiple techniques, much research has focused on the chronology of the xiaoqinling gold field (guo et al., 2009; he et al., 2009; wang et al., 2008; zhang et al., 2009a). the 40ar/39ar ages of biotite and sericite at the yangzhaiyu gold deposit area indicate two stages of gold mineralization (li et al., 2012b), one from 134.5 to 132.3 ma and the other from 124.3 to 123.7 ma. in comparison, the ages of gold-bearing quartz veins at the dongchuang gold deposit exhibit multi-stage mineralization: 142.9±2.9ma, 132.2±2.6ma and 128.3±6.2ma (sericite 40ar/39ar age) (li et al., 2002). ren (2012) suggested that the 40ar/39ar age of the fancha gold deposit was 130.5 ma or 120.2 ma, based on two sericite table 3. the o-h isotopic compositon of quartz in the fancha gold deposit. sample host mineral stage homogenization temperature/°c δdh 2 o (‰) δ18oqz(‰) δ18oh 2 o(‰) fx013 quartz i 380 -87 10.8 6.28 fx027 quartz ii 320 -66.1 10.7 4.49 fx032 quartz ii 320 -58.5 10.5 4.29 fx015 quartz iii 270 -53.1 10.5 2.44 fx016 quartz iii 270 -54.1 11.4 3.34 fx028 quartz iv 240 -79 10.8 1.36 figure 9. a) xco2 vco2 (40°c) ρ th diagram of co2-h2o-nacl inclusions with a salinity of 6%; b) xco2 vco2 (40°c) p diagram of co2-h2o-nacl inclusions with a salinity of 6% (after schwartz, 1989). g eologia c roatica yu et al.: ore-forming fluids of the fancha gold deposit, lingbao, henan province 139 samples. these estimates suggest formation in the early cretaceous, during the yanshanian period. it is noteworthy that in yangzhaiyu and dongchuang, similar gold mineralization events occurred in the same period. considering the isotopic composition and micro-thermometer evidence of the fluid inclusion data, it can be concluded that the fancha gold deposit experienced two stages of hydrothermal activity. 5.2. metallogenic conditions 5.2.1. geological conditions according to previous reports, the main mineral assemblages of the fancha gold deposit are quartz-pyrite-chalcopyrite, quartzpyrite-chalcopyrite-galena-sphalerite-gold and quartz-carbonatepyrite, of predominantly fine-grained and metasomatic texture. wall rock alteration mainly includes silicification, beresitization, potash feldspathization and carbonation, where beresitization is an important criterion for ore prospecting. other studies also show that the fancha gold deposit belongs to the yanshanian (ren, 2012), a period when lithospheric thinning and asthenosphere upwelling events occurred very frequently in eastern china (mao et al., 2010; mao et al., 2005). in the regional tectonic setting, extension stretch, archean metamorphic core uplift and granite emplacement resulted in strengthening regional metamorphism, causing formation of metamorphic fluids from early plate collision and continued activity. activated deep fluids or the early metamorphic fluid rise along the well-formed fracture zone, extracting minerals of the wall rock during migration. later, they formed into hydrothermal ore and, minerals, resulting in the taihua group stratum. the ore-bearing hydrothermal fluid was enriched within the fractures and formed the fancha gold deposit. 5.2.2. metallogenic fluid properties micro-thermometer measurements and petrographic observations show that the fancha gold mineralization fluid system experienced regular changes: ore-forming fluids from the early stage of a h2o-co2-nacl fluid system to the co2-h2o fluid system of the main metallogenic stage, and finally evolving into the h2o-nacl fluid system. from stages ⅱ to v, the average homogenization temperature declined from 283.6 ℃, to 273.8 ℃, to 245.5 ℃ and finally 217.7 ℃. in general, the fluid salinity was low and changed little (mean 9.24, 6.45, 8.79 and 5.78 wt% nacl equiv., respectively). as discussed above and according to some previous reports, the fancha ore-forming fluids show the following characteristics: 1. low homogenization temperatures, between 180 ℃ and 360 ℃. 2. low salinity range from 5 to 10 wt% nacl equiv. with little variation. 3. medium density range from 0.50 to 0.97g/cm3, with little variation. 4. fluid mineralization pressure from 70 to 180mpa, and mineralization depth from 3.5 to 6.7km. 5. wall rock alteration including silicification, chlorite and sericitization, and an assumed weakly acidic its ore-forming environment. in summary, the main metallogenic fluid of the fancha gold deposit is a low-temperature, low-salinity, medium-density nacl-h2o-co2 fluid system. the mineralization environment had low pressure, and was weakly acidic. 5.2.3. source of the metallogenic fluid the source of the metallogenic fluid is inferred from the hydrogen and oxygen isotope composition of the fluid inclusions. the isotope data of the fancha gold deposit in various stages of mineralization were mapped on the δ18oh2o–δdh2o diagram (fig. 10). at only one stage (the quartz feldspar stage), does the data point fall below the primary magmatic water, while for the other stages, namely quartz coarse pyrite and quartz fine pyrite stages, all four data points were located near the left boundary of metamorphic water. the data point of stage (ⅳ) is below the low left boundary of metamorphic water indicating that the metallogenic fluid was mainly metamorphic water (fig 10). there is a trend towards the meteoric water line, indicating the addition of meteoric fluid. furthermore, according to the discussion above, the fancha gold metallogenic fluids are characterized by low temperature, low salinity and high co2 levels, in contrast to typical magmatic hydrothermal fluids (high temperature and high salinity). thus, we suggest that the metallogenic fluid may be hydrothermal fluid of metamorphic origin. in summary, at the early stages of mineralization, metallogenic fluids were mainly metamorphic fluids, but during the main mineralization stage, the fluid was a mix of metamorphic hydrothermal fluids and meteoric fluids. at the final stage, the fluid is mostly meteoric water. 5.3. mineralization process 5.3.1. the evolution of the metallogenic fluids during the quartz coarse-grained pyrite stage, there were primarily three-phase co2-bearing inclusions and some three-phase co2-rich inclusions. the inclusions discovered at the quartz finegrained pyrite stage were mostly three-phase co2-rich inclusions, three-phase co2-bearing inclusions and two-phase aqueous inclusions. petrographic observation shows that three-phase co2-bearing inclusions with a different vapour-liquid ratio coexisted with the two-phase aqueous inclusions in this stage (fig. 7b1-b3). during the polymetallic sulphides stage, three-phase co2-rich inclusions were dominant, and some other visible inclusions or the same type of inclusions with different vapour-liquid ratios were also observed in the same field of view. the homogenization temperature of inclusions was similar. the fact that inclusions with different gas-liquid ratios have a similar homogenization temperature suggests that in the primary mineralization figure 10. δdh2o(‰)-δ18oh2o(‰)diagram of the fancha gold deposit (after taylor, 1974). g eo lo gi a c ro at ic a geologia croatica 72 / special issue140 stage, the inclusions were captured in an uneven state (lu, 2004, 2008, 2014). the inclusions in the carbonate stage are generally small and sparsely distributed, and mainly composed of twophase aqueous inclusions and a few three-phase co2-bearing inclusions. occasionally three-phase co2-rich inclusions were also observed. evidence above reflects both the initial metallogenic fluid of nacl-h2o-co2 injected along the fracture, and the subsequent mixing of meteoric fluid leading to a temperature drop. furthermore, the pressure was reduced due to changes in the tectonic environment. consequently, fluid immiscibility occurred, characterized by co2 escaping, and the whole system evolved into a nacl-h2o and h2o-co2 fluid system. as can be seen from the salinity/temperature graph (fig. 11), the inclusion temperatures overlapped and the salinity showed a declining trend. at various stages, mineral compositions represent both different fluid temperatures and crystallized mineral compositions. the results also show that declining salinity has a positive effect on the crystallization of the minerals. in addition, from the microscopic temperature measurement, we observed combinations of the same salinity but different temperatures, or of different salinities but the same temperature. at the quartz fine-grain pyrite stage, the quartz polymetallic sulfide stage, and the main metallogenic stage, the salinity data are clearly separated into low and high salinity groups, suggesting immiscibility of the ore-forming fluids. that, together with the hydrogen and oxygen isotope results, suggests that in the early stage, fluids were metamorphic and hydrothermal, of low temperature, and high salinity. in the primary mineralization stage, the main fluids were metamorphic hydrothermal fluid mixed with meteoric water. in the late mineralization stage, the main fluids were meteoric water of low-temperature and low-salinity. 5.3.2. the gold mineralization mechanism boiling and fluid immiscibility are considered to be the main gold precipitation mechanisms in many deposits. boiling should have the following indicators: (1) explosive breccia exists in ore bodies; (2) gas-liquid ratio and homogeneous temperature of inclusions vary greatly in the same stage (hayba et al., 1986). there is no obvious sign of boiling in the fancha gold deposit, and the existence of multi-stage fluids can be seen in field observations. as discussed earlier, the homogenization temperature of the fluid inclusions in the deposit is low and has shown little change. therefore, this paper explains the enrichment of gold in the deposit from the point of view of fluid immiscibility. figure 11. salinity-homogenization temperature diagram of fluid inclusions in the fancha gold deposit. figure 12. schematic diagram of metallogenic model of the fancha gold deposit. g eologia c roatica yu et al.: ore-forming fluids of the fancha gold deposit, lingbao, henan province 141 the coexistence of two or more fluids in a system is called the immiscibility of fluids (lu, 2004; roedder, 1992). scholars discovered the mineralization of hydrothermal gold deposits is closely related to the immiscibility of h2o-co2-nacl fluid (craw, 1992; hu et al., 2005; lu, 2014). immiscibility causes a phase separation of the single fluid phase, breaking the balance of the original fluid system, resulting in precipitation of valuable components. microscopic observation of the fancha gold deposit inclusions shows a group of primary inclusions (formed simultaneously at a single mineral, including two-phase aqueous inclusions, three-phase co2-bearing inclusions and three-phase co2-rich inclusions) can co-exist in the same field of view, although the filling degree is very different. they formed a continuous series, and occasionally there are daughter mineral-bearing inclusions. the above phenomenon illustrates the petrographic characteristics of fluid immiscibility. at the primary mineralization stage, there are two-phase co2-bearing inclusions and three-phase co2-rich inclusions with different vapour-liquid ratios. while these two types of inclusions have different means of homogenization, their homogenization temperatures are similar. for the polymetallic sulfide stage, the homogenization temperature of three two-phase aqueous inclusions is 257.6 ℃, 238.7 ℃ and 240.0 ℃, with a mean of 245.4 ℃, equalizing to a liquid phase. the homogenization temperature of two-phase co2-rich inclusions ranges from 235 to 265 ℃, with an average of 245.5℃, equalizing to a vapour phase. these two inclusions formed at the same time but with different end-members, and with similar homogenization temperatures but different means of homogenization. considering both the definition of immiscible inclusions and the microscopic features of the observed inclusions, it can be concluded that they are immiscible inclusions. fluid immiscibility is the main metallogenic mechanism of the fancha gold deposit. furthermore, h-o isotope mapping (fig. 10) and the homogenization temperature-salinity data (fig. 11), suggest that metallogenic fluids in the primary mineralization stage were mixed significantly with meteoric water. therefore, the mixture of fluids may also be one of the metallogenic mechanisms for the fancha gold deposit. 5.3.3. the metallogenic process geological and mineralogical data presented here support a preliminary idealized fluid-based mineralization model for the fancha gold deposit. the fancha gold deposit is located in the north china craton. the collision of the yangtze and north china cratons occurred 245–210ma ago (ames et al., 1993; li et al., 2011). at the end of the mid-triassic, the strong compressional environment led to different degrees of metamorphic deformation of the strata. severe dehydration of a large number of water-bearing minerals resulted in the formation of metamorphic hydrothermal fluid with k, na and si, and various volatiles. the metallogenic hydrothermal fluid rose along fractures, accompanied by a potash alteration that is closely related to the gold-bearing quartz veins (stage ⅰ). with the qinling orogenic belt thrust from north to south, the strata experienced varying degrees of deterioration and deformation, and metamorphic fluids were formed once again (chen et al., 1998; mao et al., 2005). as the temperature declined in the high-pressure ductile shear environment, metamorphic fluids rich in co2 and other volatiles formed large, weakly mineralized milky quartz veins in some parts (stage ⅱ). fluid inclusions were mainly highly filled three-phase co2-bearing inclusions and some three-phase co2-rich inclusions. large quartz veins that formed early, developed a series of small fractures due to tectonic stress. ore-bearing metamorphic hydrothermal fluid and some meteoric water filled the fractures, forming fine-pyrite smoky quartz veins (stage ⅲ). in this stage, the main inclusions are three-phase co2-rich inclusions, threephase co2-bearing inclusions and two-phase aqueous inclusions. fluid mixing may have occurred in this stage. in the late mineralization stage, a small amount of metamorphic fluid and meteoric water mixed and filled the fractures of the silica fine-pyrite veins, forming polymetallic sulphide veins (stage ⅳ). at this stage, the main inclusions were three-phase co2-rich inclusions and two-phase aqueous inclusions; different types of inclusions but with similar homogenization temperature. for the same type of inclusions, the gas-liquid ratio continuously changes. at this stage, the tectonic environment altered from compressive to tensile, and the decompression caused the original fluid to decompress and potentially boil. in addition, the mixture of meteoric water caused the temperature of the original high-temperature metallogenic fluid to decline, resulting in immiscibility of the fluid. the metallogenic fluid is separated from the nacl-h2o-co2 fluid system into a h2o-nacl and co2-h2o fluid system, with co2 acting as a ph buffer in the metallogenic fluid. the metallogenic elements are in a weak acid environment. the au-s complex had the highest solubility (lu, 2008), then co2 escape caused au to precipitate from the fluid. the immiscibility caused the metallogenic material to precipitate and be enriched at favourable locations. as the meteoric water continued mixing, the fluid properties changed further. the temperature and pressure continued to decline, associated with further escape of co2. in the late mineralization stage, meteoric water formed some weakly developed carbonate veins (stage ⅴ). 6. conclusions both detailed field investigations and laboratory research were undertaken on the fancha gold deposit. the geological characteristics of the deposit were identified and insights into the fluid inclusions at various stages of mineralization in terms of petrography, thermometry and stable isotope geochemistry were obtained. the main conclusions are: 1. the fancha gold deposit is a typical quartz vein type gold deposit in the xiaoqinling gold field. the main ore minerals are pyrite, chalcopyrite, native gold, sphalerite and galena, gangue minerals include quartz and calcite. according to the combination of minerals and vein interpenetration, the metallogenic process can be divided into five metallogenic stages: the quartz-k-feldspar (i), quartz-coarse pyrite (kagami et al., 1995), quartz-fine pyrite (iii), quartz-polymetallic sulfide (iv) and carbonate stages (v). gold was mainly precipitated in stages iii and iv. 2. the petrographic observations of fluid inclusions show that in the fancha gold deposit, there are mainly three-phase co2bearing, three-phase co2-rich and two-phase aqueous inclusions. regarding the composition of inclusions, there are mainly threephase co2-bearing and a few three-phase co2-rich inclusions in stage ⅱ; mainly three-phase co2-bearing inclusions, two-phase aqueous inclusions and a small amount of three-phase co2-rish inclusions in stage ⅲ; in stage iv, the main types are three-phase co2-rich and a few two-phase aqueous inclusions; for stage v the main ones are two-phase aqueous, a small number of twophase co2-bearing and three-phase co2-rich inclusions. g eo lo gi a c ro at ic a geologia croatica 72 / special issue142 3. the fluid inclusions temperature data show that metallogenic fluids are generally of low temperature and salinity, features of co2-rich metamorphic fluids. in the early mineralization stage, the main fluids were metamorphic water, while in the primary mineralization stage, the main fluids were mixtures of metamorphic and meteoric water. in the late stage, most fluids were meteoric water. 4. the immiscibility and mixing of fluids are the primary precipitation mechanisms of the fancha gold deposit. references ames, l., tilton, g.r. & zhou, g.z. (1993): timing of collision of the sino-korean and yangtze cratons – u-pb zircon dating of coesite-bearing eclogites.– geology, 21/4, 339–342. doi: 10.1130/0091-7613(1993)021<0339:tocots>2.3.co;2 bodnar, r.j. (1993): revised equation and table for determining the freezing-point depression of h2o-nacl solutions.– geochim. cosmochim. acta, 57/3, 683–684. doi: 10.1016/0016-7037(93)90378-a chen, y.j. (2013): the development of continental collision metallogeny and its application.– acta petrologica sinica, 29/1, 1–17. chen, y.j., guo, g.j. & li, x. (1998): metallogenic geodynamic background of mesozoic gold deposits in granite-greenstone terrains of north china craton.– sci china ser d, 41/2, 113–120. doi: 10.1007/bf02932429 chen, y.j., ni, p., fan, h.r., pirajno, f., lai, y., su, w.c. & zhang, h. (2007): diagnostic fluid inclusions of different types hydrothermal gold deposits.– acta petrologica sinica, 23/9, 2085–2108. doi: 10.3969/j.issn.1000-0569.2007.09.009 chen, y.j., pirajno, f. & qi, j.p. (2008): the shanggong gold deposit, eastern qinling orogen, china: isotope geochemistry and implications for ore genesis.– j. asian earth sci., 33/3–4, 252–266. doi: 10.1016/j.jseaes.2007.12.002 chi, g.x. & lu, h.z. (2008): validation and representation of fluid inclusion microthermometric data using the fluid inclusion assemblage (fia) concept.– acta petrologica sinica, 24/9, 1945–1953. doi: 10.1134/s0869593808050109 clayton, r.n., o’neil, j.r. & mayeda, t.k. (1972): oxygen isotope exchange between quartz and water.– journal of geophysical research, 77/17, 3057–3067. doi: 10.1029/jb077i017p03057 collins, p.l.f. (1979): gas hydrates in co2 – bearing fluid inclusions and the use of freezing data for estimation of salinity.– economic geology, 74/6, 1435–1444. doi: 10.2113/gsecongeo.74.6.1435 craw, d. (1992): fluid evolution, fluid immiscibility and gold deposition during cretaceous recent tectonics and uplift of the otago and alpine schist, new-zealand.– chem. geol., 98/3–4, 221–236. doi: 10.1016/0009-2541(92)90186-9 ding, t.p. (1980): hydrogen and oxygen isotope geochemistry, geological publishing house, beijing. fan, h.r., xie, y.h., zhai, m.g. & jin, c.w. (2003): a three stage fluid flow model for xiaoqinling lode gold metallogenesis in the he’ nan and shaanxi provinces, central china.– acta petrologica sinica, 19/2, 260–266. doi: 10.3969/j. issn.1000–0569.2003.02.007 fan, h.r., xie, y.h., zhao, r. & wang, y.l. (2000a): dual origins of xiaoqinling gold-bearing quartz veins: fluid inclusion evidence.– chinese sci. bull., 45/15, 1424–1430. doi: 10.1007/bf02886252 fan, h.r., xie, y.h., zheng, x.z. & wang, y.l. (2000b): ore-forming fluids in hydrothermal breccia-related gold mineralization in qiyugou, henan province.– acta petrologica sinica, 16/4, 559–563. doi: 10.3969/j.issn.1000–0569.2000.04.015 feng, j.z., zhang, d.t., zhang, w.m., wang, x.c., cui, x.x., liu, z.y. & wang, z.q. (2014): ree geochemical characteristics of xiaoqinling gold deposits and their geological significance.– geoscience, 28/6, 1151–1160. doi: 10.3969/j.issn.1000-8527.2014.06.005 gao, x.y., zhao, t.p., gao, j.f., xue, l.w. & yuan, z.l. (2012): la–icp-ms zircon u-pb ages,hf isotopic composition and geochemistry of adakitic granites in the xiaoqinling region,the south margin of the north china block.– geochimica, 41/4, 303–325. doi: 10.19700/j.0379-1726.2012.04.002 goldstein, r.h. (2001): fluid inclusions in sedimentary and diagenetic systems.– lithos, 55/1–4, 159–193. doi: 10.1016/s0024-4937(00)00044-x guo, b., zhu, l.m., li, b., gong, h.j. & wang, j.q. (2009): zircon u-pb age and hf isotope composition of the huashan and heyu granite plutons at the southern margin of north china craton: implications for geodynamic setting.– acta petrologica sinica, 25/2, 265–281. hayba, d.o., foley, n.k. & healdwetlaufer, p. (1986): characteristics that distinguish types of epithermal deposits.– j. geochem. explor., 25/1–2, 231–231. doi: 10.1016/0375-6742(86)90016-6 he, y.h., zhao, g.c., sun, m. & xia, x.p. (2009): shrimp and la-icp-ms zircon geochronology of the xiong’er volcanic rocks: implications for the paleo-mesoproterozoic evolution of the southern margin of the north china craton.– precambrian res., 168/3–4, 213–222. doi: 10.1016/j.precamres.2008.09.011 hu, f.f., fan, h.r., shen, k., zhai, m.g., jin, c.w. & chen, x.s. (2005): nature and evolution of ore-forming fluids in the rushan lode gold deposit, jiaodong peninsula of eastern china.– acta petrologica sinica, 21/5, 1329–1338. doi: 10.3969/j. issn.1000-0569.2005.05.002 kagami, h., yuhara, m., tainosho, y., iizumi, s., owada, m. & hayama, y. (1995): sm-nd isochron ages of mafic igneous rocks from the ryoke belt, southwest japan – remains of jurassic igneous activity in a late cretaceous granitic terrane.– geochem. j., 29/2, 123–135. doi: doi 10.2343/geochemj.29.123 li, j.w., bi, s.j., selby, d., chen, l., vasconcelos, p., thiede, d., zhou, m.f., zhao, x.f., li, z.k. & qiu, h.n. (2012a): giant mesozoic gold provinces related to the destruction of the north china craton.– earth planet. sc. lett., 349, 26–37. doi: 10.1016/j.epsl.2012.06.058 li, j.w., li, z.k., zhou, m.f., chen, l., bi, s.j., deng, x.d., qiu, h.n., cohen, b., selby, d. & zhao, x.f. (2012b): the early cretaceous yangzhaiyu lode gold deposit, north china craton: a link between craton reactivation and gold veining.– economic geology, 107/1, 43–79. doi: 10.2113/econgeo.107.1.43 li, n., chen, y.j., fletcher, i.r. & zeng, q.t. (2011): triassic mineralization with cretaceous overprint in the dahu au-mo deposit, xiaoqinling gold province: constraints from shrimp monazite u-th-pb geochronology.– gondwana res., 20/2–3, 543–552. doi: 10.1016/j.gr.2010.12.013 li, q.z., chen, y.j., zhong, z.q., li, w.l., li, s.r., guo, x.d. & jin, b.y. (2002): 40ar–39ar dating on the metallogenesis of the dongchuang gold deposit in the xiaoqinling area.– acta geol sin-engl, 76/4, 488–493. li, s.m., qu, l.q., su, z.b., huang, j.j., wang, x.s. & yue, z.s. (1996): geology and metallogenic prognosis of gold deposits in the xiaoqinling district, geological publishing house, beijing, 250 p lu, h.z. (2004): fluid inclusions, science press, beijing, 487 p – (2008): role of co2 fluid in the formation of gold deposits: fluid inclusion evidences.– geochimica, 37/4, 321–328. doi: 10.19700/j.0379-1726.2008.04.004 – (2014): fluid inclusion petrography:a discussion.– geological journal of china universities, 20/2, 177–184. doi: 10.16108/j.issn1006-7493.2014.02.003 lu, h.z., zhu, x.q., shan, q. & wang, z.g. (2013): hydrothermal evolution of gold-bearing pyrite and arsenopyrite from different types of gold deposits.– mineral deposits, 32/4, 823–842. doi: 10.16111/j.0258-7106.2013.04.014 lu, x.x., wei, x.d., yu, z.p. & ye, a.w. (2003): characteristics of ore-forming fluids in gold deposits of xiaoqinling-xiong’ershan area.– mineral deposits, 22/4, 377–385. doi: 10.16111/j.0258-7106.2003.04.007 luan, s.w., cao, d.c., fang, y.k. & wang, j.y. (1985): geochemistry of xiaoqinling gold deposits.– journal of mineralogy and petrology, 02, 2–7. doi: 10.19719/j.cnki.1001-6872.1985.02.001 luan, s.w. & chen, s.d. (1990): main ore controlling factors and metallogenic model of gold deposits in xiaoqinling area.– contributions to geology and mineral resources research/4, 1–14. mao, j.w., goldfarb, r.j., zhang, z.w., xu, w.y., qiu, y.m. & deng, j. (2002): gold deposits in the xiaoqinling-xiong’ershan region, qinling mountains, central china.– miner. deposita, 37/3–4, 306–325. doi: 10.1007/s00126-001-02481 mao, j.w., xie, g.q., pirajno, f., ye, h.s., wang, y.b., li, y.f., xiang, j.f. & zhao, h. j. (2010): late jurassic-early cretaceous granitoid magmatism in eastern qinling, central-eastern china: shrimp zircon u-pb ages and tectonic implications.– aust. j. earth sci., 57/1, 51–78. doi: 10.1080/08120090903416203 mao, j.w., xie, g.q., zhang, z.h., li, x.f., wang, y.t., zhang, c.q. & li, y.f. (2005): mesozoic large-scale metallogenic pulses in north china and corresponding geodynamic settings.– acta petrologica sinica, 21/1, 169–188. doi: 10.3321/j. issn:1000-0569.2005.01.017 melfos, v. & voudouris, p. (2016): fluid evolution in tertiary magmatic-hydrothermal ore systems at the rhodope metallogenic province, ne greece. a review.– geologia croatica, 69/1, 157–167. doi: 10.4154/gc.2016.12 ni, s.j. (1994): a new model of gold mineralization with the contribution of meso-basic dyke rocks in xiaoqinling, southwest jiaotong university press, chengdu, 136 p. nie, f.j., jiang, s.h. & zhao, y.m. (2001): lead and sulfur isotopic studies of the wenyu and the dongchuang quartz vein type gold deposits in xiaoqinling area, henan and shaanxi provinces, central china.– mineral deposits, 20/2, 163–173. doi: 10.16111/j.0258-7106.2001.02.009 qi, j.p., chen, y.j. & li, q.z. (2002): synthesis of hydrothermal metallogenesis in xiaoqinling orogenic gold field.– mineral deposits/a1, 1009–1012. doi: 10.16111/ j.0258-7106.2002.s1.260 ren, z.y. (2012): mineralization characteristic and genesis of the fancha and yisishan gold deposit in the eastern xiaoqinling district [master mineral deposits]: china university of geosciences (wuhan), 106 p. roedder, e. (1984): fluid inclusions.– rev. mineral, 12, 1–&. – (1992): fluid inclusion evidence for immiscibility in magmatic differentiation, 5–20 p. schwartz, m.o. (1989): determining phase volumes of mixed co2–h2o inclusions using microthermometric measurements.– miner. deposita, 24/1, 43–47. shepherd, t.j., rankin, a.h. & alderton, d.h.m. (1985): a practical guide to fluid inclusion studies blackie academic & professional, london. g eologia c roatica yu et al.: ore-forming fluids of the fancha gold deposit, lingbao, henan province 143 tasev, g., serafimovski, d. & serafimovski, t. (2018): evolution of oreforming fluids in the bukovik-kadiica porphyry cu deposit, republic of macedonia.– geologia croatica, 71/1, 1–18. doi: 10.4154/gc.2018.01 touret, j.l.r. (2001): fluids in metamorphic rocks.– lithos, 55/1–4, 1–25. doi: 10.1016/s0024-4937(00)00036-0 wang, t.h., mao, j.w. & wang, y.b. (2008): research on shrimp u-pb chronology in xiaoqinling-xionger’ shan area: the evidence of delamination of lithosphere in qinling orogenic belt.– acta petrologica sinica, 24/6, 1273–1287. wang, y.t., ye, h.s., ye, a.w., shuai, y., li, y.g. & zhang, c.q. (2010): zircon shrimp u-pb ages and their significances of the wenyu and niangniangshan granitic plutons in the xiaoqinling area, central china.– scientia geologica sinica, 45/1, 167–180. doi: 10.3969/j.issn.0563-5020.2010.01.015 wang, z.w. & zhou, y.z. (1996): the characteristic and geological significance of ore-forming fluid of gold deposits in xiaoqinling area.– bulletin of mineralogy petrology and geochemistry, 15/4, 225–227. xu, x.s., griffin, w.l., ma, x., o’reilly, s.y., he, z.y. & zhang, c.l. (2009): the taihua group on the southern margin of the north china craton: further insights from u-pb ages and hf isotope compositions of zircons.– miner. petrol., 97/1–2, 43–59. doi: 10.1007/s00710-009-0062-5 zhang, d.q., she, h.q., feng, c.y., li, d.x. & li, j.w. (2009a): geology, age, and fluid inclusions of the tanjianshan gold deposit, western china: two orogenies and two gold mineralizing events.– ore geol. rev., 36/1–3, 250–263. doi: 10.1016/j.oregeorev.2009.06.002 zhang, y.h., mao, j.w., zongyan, l.i., cuijie, q., zhang, x.m. & zhang, x.w.i. (2009b): ore deposit types and characteristics of magmatic-hydrothermal systems and implication for exploration.– acta geologica sinica, 83/3, 399–425. doi: 10.3321/j.issn:0001-5717.2009.03.009 zhao, h.x., ji, j., zhao, z., chen, j.s. & li, b. (2017): fluid inclusion characteristics and ore genesis of the dahu gold and molybdenum deposits in the xiaoqinling gold belt.– geological journal of china universities, 23/1, 72–82. doi: 10.16108/j.issn1006-7493.2015122 zhou, z.j., chen, y.j., jiang, s.y., hu, c.j., qin, y. & zhao, h.x. (2015): isotope and fluid inclusion geochemistry and genesis of the qiangma gold deposit, xiaoqinling gold field, qin ling orogen, china.– ore geol. rev., 66, 47–64. doi: 10.1016/j.oregeorev.2014.10.020 zhou, z.j., chen, y.j., jiang, s.y., zhao, h.x., qin, y. & hu, c.j. (2014): geology, geochemistry and ore genesis of the wenyu gold deposit, xiaoqinling gold field, qinling orogen, southern margin of north china craton..– ore geol. rev., 59, 1–20. doi: 10.1016/j.oregeorev.2013.12.001 www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2024 | 77/2 | 127–144 | 11 figs. | 5 tabs. | 2 supplements | 1. introduction karst aquifers are challenging to exploit, manage, and protect due to the extreme variability of hydraulic properties (palmer, 2010). the pathways and residence time of groundwater within the subsurface often depend upon not only the geometry of a complex underground network of conduits and fissures, but also the prevailing hydrological conditions (ford & willams, 2007; vasić et al., 2020; milanović et al., 2023; torresan et al., 2020; terzić et al., 2012; torkar & brenčič, 2015; živanović et al., 2022). the dinaric karst system represents a geologically heterogeneous, south european orogenic belt, developed in highly vulnerable carbonate aquifers, which are the main drinking water resource for the region. the system stretches from the carso area in italy in the north and crosses over several countries from slovenia to albania (stevanović et al., 2016). the north dinaric karst in croatia remains uniquely unaffected by its neighbouring countries, boasting very high groundwater quality (biondić 2013; pavlić & parlov, 2019). hence, it has been declared as part of the first-degree strategic reserve of drinking water by the croatian water management strategy (water management strategy 2008). these strategic reserves include the gacka river catchment in the south, aquifers across kapela tracing hydrological processes: insights from hydrochemical and isotopic investigations in the northern part of croatian dinaric karst ivana boljat1, josip terzić1, željko duić2,*; jasmina lukač reberski1, ana selak1 and maja briški1 1 croatian geological survey, department of hydrogeology and engineering geology, sachsova 2, 10000 zagreb, croatia 2 university of zagreb, faculty of mining, geology and petroleum engineering, department of geology and geological engineering, pierottijeva 6, zagreb, 10000, croatia; (*corresponding author: zeljko.duic@rgn.unizg.hr) doi: 10.4154/gc.2024.09 abstract this study presents the findings derived from a three-year monitoring programme focusing on the hydrochemical composition and stable isotope signatures (δ18o, δ2h) within the vulnerable karst groundwater system in croatia's northern dinaric karst region. covering an area of 1980 km2 across kapela mountain and its foothills, this groundwater system falls within the kupa river basin and encompasses the catchment areas of the main springs across two spring levels of the dobra, mrežnica, and slunjčica rivers (namely the vitunj, zagorska mrežnica, dretulja, veliko vrelo, gojak, tounjčica, mrežnica, and slunjčica springs). given the complex hydrogeological framework, prior studies have not extensively addressed the hydrochemical characteristics of this region, thereby necessitating a comprehensive investigation to elucidate system dynamics. this paper outlines the first investigation employing stable isotopic analyses within the karst groundwater system of kapela mt. the main results and conclusions of the research include: (i) the aquifers across kapela mt. drain mainly limestones, (ii) water–rock interaction and carbonate weathering are significant contributors to water geochemistry, (iii) there is a slight human impact on the gojak and tounjčica spring waters, (iv) the mean residence time of water in the observed aquifer is up to 1.5 years, (v) the new lmwl was calculated for kapela mt. based on a three-year dataset (june 2018 – may 2021), (vi) in the north dinaric karst, the predominant origin of precipitation is from the mediterranean air mass, (vii) velebit mt. has a strong influence on the precipitation isotopic composition of the study area. mt., and the mountainous section of the kupa river’s immediate catchment to the north. the catchments of the gacka river (mandić et al., 2008; lukač reberski et al., 2009, 2013; stroj et al., 2023) and kupa river (biondić et al., 2021; pavlić & parlov, 2019; frančišković-bilinski et al., 2013), have been hydrogeological explored. however, there is limited knowledge regarding the hydrogeological and groundwater characteristics of the aquifer spanning kapela mt. and the ogulin-plaški valley, with only local studies conducted (bočić et al., 2015; bonacci & andrić, 2010; buljan et al., 2019; gladović et al., 2023; terzić et al., 2012). this research endeavour is poised to address this gap in knowledge. the local hydrogeological studies, specifically focusing on hydrochemical and stable isotopic analyses were carried out in the neighbouring area of the plitvice lakes catchment (babinka, 2007; biondić et al., 2006, 2010; čanjevac et al., 2023; hunjak et al., 2013; meaški et al., 2016), krbavica (stroj et al., 2020) and velebit mt. (stroj & paar, 2019). long-term hydrochemical monitoring provides valuable insights into the mechanisms governing water-rock interactions, dissolution processes, groundwater flow pathways, and anthropogenic impacts in karst aquifers (gibbs, 1970; article history: manuscript recieved: january 13, 2024 revised manuscript accepted: april 18, 2024 available online: june 21, 2024 keywords: karst hydrogeology, environmental tracer, excess air, mean recharge altitude, local meteoric water line, kupa river catchment g eo lo gi a c ro at ic a 128 geologia croatica 77/2 meybeck 1987; akter & ahmed, 2019; marković et al., 2022). moreover, stable isotopes, such as oxygen-18 (δ18o) and deuterium (δ2h), serve as natural tracers, offering clues about the origin (vreča et al., 2007; hunjak, 2013; mezga et al., 2014), mean residence time (kralik, 2015), mean recharge altitudes (mohammed et al., 2014; fiket et al., 2021), mixing patterns (terzić et al., 2014), and the groundwater dynamic (mance et al., 2022) within the karst system. we conducted a comprehensive analysis using a threeyear dataset, examining hydrochemical and physical parameters alongside the δ18o and δ2h stable isotope content of the groundwater. the investigation spanned eight distinct locations (vitunj, zagorska mrežnica, dretulja, veliko vrelo, gojak, tounjčica, mrežnica, and slunjčica springs) within two spring zones situated in the area of kapela mt. we integrated insights from the neighbouring catchments to interpret our research findings. this integration enriches the depth and scope of the analysis. the research holds significant value as it marks the inaugural regional study of its kind within the northern part of the dinaric karst in croatia. 2. settings 2.1. study area the study area belongs to the black sea basin and is located in the northern part of the croatian dinaric karst, spanning an approximate area of 1980 km2. it encompasses the catchments of the main springs of the dobra, mrežnica, and slunjčica rivers catchments (fig 1). the northern boundary of the investigated area is demarcated by the interface between the immediate catchments of the kupa and dobra rivers. the western boundary coincides with the watershed between the adriatic and danube river basins, while the southern boundary extends from the plitvice lakes to slunj. the eastern boundary is defined by the springs of the dobra, mrežnica, and slunjčica rivers. catchment boundaries for the zagorska mrežnica, dretulja, veliko vrelo, and slunjčica springs were defined during the establishment of sanitary protection zones. however, it should be noted that these boundaries are zonal and depend upon the hydrological conditions prevailing within the respective watershed (terzić et al., 2012; biondić, 2013; buljan et al., 2019). the area falls within the continental climatic belt, characterized by mountain climate elements. kapela mt., with a peak of 1534 m a.s.l., acts as a barrier to moisture-laden air masses from the west, causing significant precipitation. this area lacks dry periods. annual precipitation levels vary between 1750 and 2500 mm, conditioned by both vertical and horizontal relief divisions, generally increasing from se to nw. the snow cover duration averages 50 days per annum over the period from 1949 to 2022, as per croatian mete orological and hydrological service (dhmz) records. average annual air temperatures oscillate between 3 to 6°c. the ogulin-plaški valley, located at an altitude of 300 to 400 m a.s.l., experiences dry and hot summers contrasting with wet and cold winters. average annual precipitation varies from 1250 to 1750 mm, and air temperature between 10 to 11°c. dhmz records from 1949 to 2022 indicate an average yearly duration of snow cover lasting 39 days. the northern part of the dinaric karst in croatia is predominantly composed of karstified carbonate rocks, which were deposited from the triassic to lower cenozoic periods. non-karstic rocks occupy small and scattered areas, often surrounded by karst terrain (bahun 1968; buljan et al. 2019). the typical orientation in a nw-se direction can be attributed to thrust-related deformation between the palaeogene and the eocene or miocene epochs (tari, 2002; schmid et al., 2008; korbar, 2009). however, the region's evolution is still an essential subject of investigation (dragičević & velić, 2002; vlahović et al., 2005; velić, 2007; korbar, 2009;). a comprehensive basic geological map, at the 1:100,000 scale, was created for the entire research area, covered by six sheets, each accompanied by interpretations. the sheets include: delnice (savić & dozet, 1983), crikvenica (šušnjar et al., 1970), črnomelj (bukovac et al., 1983), ogulin (velić & sokač, 1982), otočac (velić et al., 1974) and slunj (korolija et al., 1980). according to the structural-geological position and lithology, the rocks within the area were divided into the following distinct hydrogeological groups (fig. 1): quaternary deposits – encompass heterogeneous depostits, mostly mixtures of rock fragments and fine-grained material. the soil covers the carbonate base across the entire area, but their hydrogeological significance is only notable within morphological depressions such as karst poljes: ogulin, plaški, lička jesenica. high permeability carbonates – represented predominantly by limestones. these formations were deposited between the jurassic and eocene periods. permeable carbonate rocks – represented predominantly by dolomitic limestone to thinner beds or interbeds of dolomite, deposited during the jurassic and cretaceous periods. low permeability carbonates – characterized by lower karstification intensity, mainly composed of dolomite, dolomitized limestone, or dolomite/limestone exchange, with dissolution cavities often filled with secondary materials including silt, sand and rock fragments. deposition occurred from the upper triassic to lower cretaceous periods. the hydrogeological relationships in the study area result from compressional tectonics (tari, 2002) and are intrinsically complex. the mountainous terrain of kapela mt. serves as the first recharge area formed by substantially fractured mesozoic limestones and dolomites exhibiting high secondary porosity. due to numerous karstic forms, the area is characterized by rare, ephemeral surface watercourses limited to karst poljes. highly karstified rocks enable the substantial accumulation of groundwater. the monitored springs vitunj, zagorska mrežnica, dretulja, and veliko vrelo emerge at the foot of the mountain, where permeable carbonate rocks meet with less permeable dolomites. the hydrogeological barrier is represented by several karst poljes with short watercourses. geomorphologically, the hydrogeological barrier is represented by the una-korana karst plateau, the largest plateau in dinaric karst (bočić et al, 2003, 2015; 2010). among these, the largest are ogulin, plaški, and ličkojeseničko polje, and smaller begovac and saborsko poljes. g eologia c roatica 129boljat et al.: tracing hydrological processes: insights from hydrochemical and isotopic investigations in the northern part of croatian dinaric karst watercourses of the zagorska mrežnica, dretulja, and lička jesenica rivers flow across the karst plateau, where they sink into the highly permeable limestones. they resurface at an elevation around 100 m lower than the plateau, eventually forming the kupa river tributaries: dobra, mrežnica, and slunjčica rivers. eight springs have been strategically selected for moni­ toring, considering their spatial distribution and contribution to the hydrological network of the three kupa river tributaries. the first spring zone encompasses four springs located at the foot of kapela mt. namely the vitunj, zagorska mrežnica, dretulja, and veliko vrelo springs. the second spring zone is represented by the gojak, tounjčica, mrežnica, and slunjčica springs, serving as the main outlets of the sinking rivers, which are formed by the springs in the first spring zone. the second spring area marks the transition between deep (classical) and shallow karst (fluviokarst) (bahun, 1968; kovačević, 2005). although this border is primarily descriptive and based solely on structural units, the entirety of the area east of the kapela mt. differs greatly from the rest of the croatian dinaric karst in terms of karstification depth. the vitunj spring forms the vitunjčica river, a main tributary of the sinking ogulinska dobra river, which resurfaces at the gojak spring, initiating the dobra river’s watercourse. the zagorska mrežnica spring is the main spring in the ogulin polje, which feeds the catchment area of the tounjčica river, or the west tributary of the mrežnica river. the dretulja spring forms the eponymous sinking river, which emerges through the mrežnica spring, serving as the starting point of the mrežnica river. the veliko vrelo spring forms the lička jesenica sinking river, proven to be connected with the slunjčica spring (engineering project institute, 1948). the discharge regime of springs and rivers in the study area shows a distinctly karstic nature, characterized by notable differences in minimum and maximum discharges and fast responses (within a day) to precipitation in the hinterland (buljan et al., 2019). an illustration of substantial fluctuations in discharge under low and high hydrological conditions is shown in figure 2. the supplementary material (1 and 2) presents all monitored springs during varying water levels. the available literature data shows that the ratio of the lowest, medium, and maximum discharges in veliko vrelo spring is 1:6.75:100 (terzić et al., 2012), in vitunjčica river figure 1. hydrogeological map of the north dinaric karst region in croatia. g eo lo gi a c ro at ic a 130 geologia croatica 77/2 1:14:143 (pavlić & parlov, 2020), and the ratio of minimum and maximum discharge of the zagorska mrežnica spring is 1:222 (biondić, 2013); 1:6:64 slunjčica (dhmz). 3. monitoring, sampling, and data analysis hydrochemical and isotopic investigations have been conducted within the study area, focusing on eight springs: the vitunj, zagorska mrežnica, dretulja, veliko vrelo, gojak, tounjčica, mrežnica, and slunjčica springs. table 1 provides details regarding the geographic position, sample numbers for chemical and isotopic analyses, and in situ measurements at selected sampling locations (fig 1). monthly observations of chemical and physicochemical parameters were undertaken over a span of 33 monitoring campaigns between september 2018 and may 2021. stable isotopes were observed in spring waters during 40 campaigns, from february 2018 to may 2021. additionally, isotopic precipitation analyses were performed in 36 campaigns, at monthly intervals from june 2018 to may 2021. the precipitation sampler was located at kapela mt. the physico-chemical parameters (water temperature, ph, specific electrolytic conductivity (sec), and oxygen concentration) were measured in situ using a wtw (multi 3630 ids set g) multi-parameter probe. the hco3 – ion concentration or alkalinity was measured in the field through volumetric titration using 1.6n h2so4 to ph 4.5, employing a hach digital titrator. the groundwater and precipitation samples were analysed in the hydrochemical laboratory of the department of hydrogeology and engineering geology of the croatian geological survey. the concentrations of the major anions (cl−, no3 –, and so4 2−) and cations (ca2+, mg2+, na+, and k+) were measured using ion chromatography (thermo scientific dionex ics-6000 hpic system). the ion analyses balance was checked by the relative deviation from the charge balance (δmeq = 100 × (σmeq+ − σmeq−)/(σmeq+ + σmeq−) < ±5%) (mandel & shiftan, 1981; domenico & schwartz, 1990). stable isotopes of oxygen and hydrogen were analyzed with a picarro l2130-i isotope and gas concentration analyzer (picarro, santa clara, ca, usa), using the secondary water isotopes standard kit (picarro) for calibration of the results. the results are presented in delta notation (‰), normalised to the international measurement standard vsmow (vienna standard mean ocean water) (craig, 1961a). precipitation was collected using oil-free palmex® rain collectors (palmex d.o.o., zagreb, croatia) that effectively prevent evaporative isotopic enrichment (michelsen et al., 2018). the sampler was positioned at the observation station of croatian roads (hac) (45°05'3422 n, 15°12'42'' e) on kapela mt, at 888 m a.s.l. the direct distance by air between the sampler and the adriatic coast is about 25 km. out of 36 samples collected, three were excluded from further interpretation due to technical difficulties. specifically, during the months of august 2018, may 2020, and january 2021, the precipitation collector funnel encountered blockages, causing figure 2. the mrežnica spring during high (a) and low water conditions (b). the spring is located within the military training area "eugen kvaternik" and is inaccessible to the general population. table 1. sampling location, altitude, type, and number of samples per analysis. location lat. (deg n) long. (deg w) altitude (m a.s.l.) no. of samples for analysis of δ2h and δ18o isotopes no. of samples for chemical analysis in situ measurements of physical parameters vitunj spring 45.291221 15.140482 345 39 32 32 zagorska mrežnica spring 45.195624 15.221742 326 40 33 32 dretulja spring 45.074659 15.342673 359 40 32 33 veliko vrelo spring 44.966213 15.460677 484 38 33 33 gojak spring 45.297340 15.262693 197 40 33 33 tounjčica spring 45.248871 15.322711 225 40 33 33 mrežnica spring 45.090260 15.495816 320 29 29 28 slunjčica spring 45.078297 15.588019 258 40 33 33 kapela mt. (precipitation) 45.092973 15.211796 888 36(33*) total 339 258 257 * number of samples taken in the interpretation g eologia c roatica 131boljat et al.: tracing hydrological processes: insights from hydrochemical and isotopic investigations in the northern part of croatian dinaric karst inadequate data. the recorded values deviated by more than 200% from the obtained maximal/minimum value, necessitating exclusion from the analyses. daily discharge data were acquired from the croatian meteorological and hydrological service (dhmz) and the croatian electric power company (hep). to delineate the hydrochemical facies of springs, monthly water samples were subjected to major anion and cation analyses. the results were used to construct a piper diagram (piper, 1944) that graphically represents the major ion ratios. the interactions among the chemical and physicochemical parameters were further analyzed using pearson's correlation coefficient (r). this statistical measure is widely employed to explore relationships between the various parameters within hydrochemical samples. the dimensionless number in question falls between the range of +1 to –1, where +1 signifies a perfect positive correlation, 0 indicates no linear relationship, and –1 denotes a perfect negative correlation between the parameters. more precisely, parameters with a correlation coefficient r > 0.7 are considered to have a strong correlation, while values between 0.5 and 0.7 indicate a moderate correlation (freedman et al. 2007). the molar ratio mg2+/ ca2+ was utilized to derive information regarding the source, evolution, and geochemical processes influencing water chemistry in aquifers (appelo & postma, 2005). analyses of oxygen (δ18o) and hydrogen (δ2h) stable isotopes in spring water and precipitation samples were used to define spring water origin by comparing it with local precipitation characteristics. the local meteoric water line (lmwl) was calculated using the ordinary least square table 2. main statistical descriptors of in situ measured parameters and major ion concentrations at the eight locations in catchment areas of dobra, mrežnica, and slunjčica rivers. site statistic t ph sec (µs/cm) o2 (mg/l) na+ (mg/l) mg2+ (mg/l) k+ (mg/l) ca2+ (mg/l) cl (mg/l) no3 (mg/l) so4 2 (mg/l) hco3 (mg/l) vi tu nj max 9.4 8.36 407 12.3 1.76 29.64 0.94 64.64 2.14 8.36 8.05 285.4 min 7.6 7.0 272 10.9 0.0 4.5 0.0 42.4 0.7 1.4 1.6 165.9 median 7.8 7.9 319 11.6 0.6 7.0 0.3 55.5 1.3 5.2 5.4 203.7 average 7.9 7.9 326 11.3 0.6 9.2 0.3 55.4 1.3 4.9 4.9 208.4 sd 0.4 0.2 33 2.0 0.3 5.7 0.2 5.4 0.3 1.7 1.9 27.2 za go rs ka m re žn ic a max 10.9 8.3 437 14.6 5.0 23.6 1.0 82.8 4.1 7.9 11.1 295.2 min 7.6 7.4 336 7.7 0.6 5.2 0.0 41.0 1.8 0.5 1.9 184.2 median 9.1 7.6 409 10.6 1.8 8.4 0.4 71.3 2.8 4.5 6.0 252.5 average 9.2 7.7 405 10.5 1.9 9.6 0.4 70.2 2.8 4.4 5.8 250.8 sd 0.8 0.2 22 2.4 0.7 4.1 0.2 8.7 0.7 1.5 2.2 24.0 d re tu lja max 10.2 8.1 488 14.3 1.8 16.7 2.0 93.9 2.6 7.4 11.6 339.2 min 8.2 0.0 423 9.0 0.0 7.2 0.0 61.8 0.5 1.3 2.3 219.6 median 8.7 7.4 462 10.4 0.6 10.7 0.3 83.5 1.1 4.4 6.4 292.8 average 8.9 7.2 461 10.2 0.6 11.1 0.4 82.6 1.3 4.4 6.4 292.1 sd 0.7 1.3 11 2.0 0.3 2.3 0.4 6.1 0.5 1.5 2.3 22.2 ve lik o vr el o max 8.7 8.1 506 14.3 1.7 22.9 0.8 84.8 2.3 8.5 8.3 347.7 min 7.0 7.4 278 10.0 0.3 8.5 0.1 48.1 0.7 2.5 2.3 253.8 median 7.8 7.5 439 11.4 0.6 14.1 0.3 73.0 1.3 5.2 5.7 285.5 average 7.7 7.5 439 11.4 0.7 14.8 0.3 73.1 1.3 5.2 5.4 284.1 sd 0.3 0.1 33 0.7 0.3 3.5 0.2 6.4 0.4 1.3 1.7 19.9 g oj ak max 16.9 8.4 432 12.8 5.2 24.0 2.8 75.7 10.6 10.4 10.3 273.3 min 7.7 7.5 344 9.5 1.7 8.0 0.2 40.5 2.1 3.3 3.0 178.1 median 10.0 7.9 391 11.2 3.4 13.1 0.8 60.7 5.1 6.3 6.6 235.5 average 11.1 7.9 392 10.6 3.5 13.1 0.9 60.7 5.1 6.5 6.5 233.8 sd 2.5 0.2 22 2.8 0.9 3.4 0.5 6.4 1.7 1.7 2.1 18.0 tu nj či ca max 16.1 8.2 659 12.1 34.9 15.0 2.4 88.3 67.1 17.6 10.9 305.0 min 6.9 7.5 355 1.9 0.8 4.5 0.2 53.0 1.8 2.7 2.5 180.6 median 9.5 7.8 393 9.5 1.8 7.5 0.6 70.1 2.8 5.9 6.2 240.3 average 9.8 7.8 407 8.4 4.0 7.8 0.7 71.1 6.5 7.2 6.2 239.8 sd 1.6 0.2 55 3.3 6.1 2.2 0.4 7.6 11.5 3.9 2.3 26.3 m re žn ic a max 13.7 8.1 470 12.6 1.2 18.0 1.8 86.0 2.8 7.7 9.2 324.5 min 6.4 6.8 387 9.6 0.1 6.3 0.1 45.8 1.1 0.5 2.6 169.6 median 9.7 7.7 446 10.4 0.8 12.4 0.7 76.7 1.7 4.3 6.0 278.2 average 9.9 7.7 443 10.3 0.7 12.5 0.8 74.8 1.8 4.4 5.9 278.8 sd 1.7 0.2 17.5 2.1 0.3 2.6 0.5 8.2 0.5 1.5 1.7 27.8 sl un jč ic a max 10.9 8.0 460 14.2 2.2 15.7 1.4 94.9 3.1 7.8 10.5 345.3 min 8.7 0.0 390 9.2 0.4 4.4 0.1 53.8 0.7 1.6 2.4 213.5 median 9.5 7.5 443 10.8 1.0 9.7 0.4 78.4 1.8 4.7 6.3 273.3 average 9.7 7.3 438 10.8 1.1 9.9 0.4 78.8 1.8 4.5 6.3 278.2 sd 0.6 1.3 17 0.8 0.4 2.9 0.3 7.1 0.5 1.4 2.1 21.3 g eo lo gi a c ro at ic a 132 geologia croatica 77/2 regression (olsr), excluding improperly collected samples. spring water isotope values were plotted and compared with the lmwl, and the groundwater lines (gwl) were calculated for the monitored springs (clark & fritz, 1997). the d-excess was calculated for each sample following the equation: d-excess = δ2h − 8δ18o (dansgaard, 1964). the d-excess can be used as an indicator of the origin of precipitation and conditions during the vapour formation (clark et al., 2015). isotopic analyses also enabled a rough estimation of spring water mean residence time (mrt) in the aquifer by using a simple equation based on observed annual oscillation amplitudes in rainwater and spring water samples. the mrt in the karst aquifers were a rough estimation using an exponential model by the following equation: t=ω–1[(a/b)–2–1]0.5 (1) where t is the mean residence time, a is the amplitude of precipitation δ18o, b is the amplitude of the spring water and the ω is the angular frequency. the theoretical background of the applied equation is elaborated upon in the works by małoszewski et al. (1983), mcguire & mcdonnell (2006), and rodgers et al. (2005). the calculation examines the sinusoidal oscillation of the stable isotope content in precipitation and the subsequent reduction of this oscillation in observed springs due to the mixing and retention of water in the karst aquifers. 4. results the descriptive statistics of the physico-chemical and chemical parameters of the sampled waters are summarised in table 2 and shown in figure 3. the ph ranges between 6.8 and 8.2, which indicates the slightly alkaline water, typical for karst aqifers. the most dispersed and highest values were observed in the gojak spring figure 3. dissolved oxygen, precipitation, ph, water temperature, and sec compared with daily discharge and precipitation data, which represent hydrological conditions. g eologia c roatica 133boljat et al.: tracing hydrological processes: insights from hydrochemical and isotopic investigations in the northern part of croatian dinaric karst water. in general, the dretulja spring water has the lowest, while the vitunj spring water has the highest ph values. the water temperature of the monitored springs ranges from 6.4 to 16.9°c, with pronounced temperature homo geniza tion of the springs at the foot of the kapela mt. the most consistent water temperature was recorded in the veliko vrelo (δ 1.7°c) and vitunj (δ 1.8°c) springs, while the water temperature in the dretulja spring oscillates around 2.4°c, and in zagorska mrežnica spring around 2.8°c. the temperature oscillations in the spring water at the second spring level are more pronounced. within the area of shallow karst, the temperature of the slunjčica spring amounts to only 2.2°c. however, the springs to the north, such as mrežnica, tounjčica, and gojak exhibit much larger temperature oscillations of δ 7.3°c, δ 9.2°c, and δ 9.2°c, respectively. the sec in spring waters ranges between 272 and 506 µs/ cm, with an anomaly noted in december 2019 in the tounjčica spring, when the sec measured 659 µs/cm. the observed anomaly is further explained in the discussion. in general, there is a trend of increasing sec values in springs from the north to the south of the study area. the vitunj spring water has the highest degree of oscillation, with the lowest overall values (median of 319 µs/cm). the median sec value in zagorska mrežnica spring water was 409 µs/cm. however, at the foot of the kapela mt. slightly higher sec values were detected in dretulja (median of 462 µs/cm) spring waters than in the veliko vrelo spring (median of 439 µs/cm). this pattern is mirrored in the second spring zone, in mrežnica (median of 446 µs/cm) and slunjčica (median of 443 µs/cm) springs. the tounjčica spring water (median of 393 µs/cm) has similar sec values to the gojak spring waters (median of 391 µs/cm), but with a higher degree of oscillation. the oxygen concentration in the monitored spring waters ranges between 7.73 to 14.63 mg/l, except for tounjčica spring water, where extremely low values up to 1.88 mg/l were observed. the median values of oxygen concentration showed the following order: vitunj (11.6 mg/l) > gojak (11.2 mg/l) > veliko vrelo (11.4 mg/l) > slunjčica (10.8 mg/l) > zagorska mrežnica (10.6 mg/l) > dretulja (10.4 mg/l) > mrežnica (10.4 mg/l) > tounjčica (9.5 mg/l). the results of the chemical analysis indicated ca2+ as a dominant cation in monitored spring waters, followed by mg2+, na+, and k+. the average contribution of ca2+ to the cation budget is 84 – 87% in all spring water, except gojak spring water, which is 78%. the dominant anion in monitored spring waters is hco3 – followed by cl–, no3 –, and so4 2–. the average contribution of hco3 – is 96% to the anion budget in the mrežnica, veliko vrelo, and slunjčica springs, 95% in the vitunj and zagorska mrežnica springs, and 93% in the dretulja and tounjčica springs. spring water mineralization was calculated from a chemical analysis of major anions and cations. the mineralization during the monitoring period was in the range of 236 – 370 mg/l for the vitunj spring, 267 – 430 mg/l for the mrežnica spring, 273 – 378 mg/l for the gojak spring, 273 – 495 mg/l for the tounjčica spring, 281 – 395 mg/l for the zagorska mrežnica spring, 306 – 450 mg/l for the dretlja spring, 317 – 455 mg/l for the slunjčica spring, and 342 – 453 mg/l for the veliko vrelo spring. the minimum, maximum, and median isotopic com position of δ18o and δ2h in monitored springs and precipitation collected on kapela mt. are reported in table 3. in spring waters, the measured δ18o values ranged from –10.65 to –8.01‰, and the δ2h values ranged from –70.46 to –50.48‰. the results align with the previous study in lika and gorski kotar regions (brkić et al., 2020; stroj et al., 2020; paar et al., 2019; hunjak, 2013). the amplitude in precipitation is expectedly much higher; the measured δ18o values ranged from –12.33 to –4.99‰, and the δ2h varied from –88.00 to –25.55‰. the higher amplitude of δ18o was observed in the spring water of vitunj spring (2.39‰), followed by the gojak (2.08‰), tounjčica (2.06‰), zagorska mrežnica (1.84‰), slunjčica (1.80‰), mrežnica (1.55‰), veliko vrelo (1.41‰) and dretulja (1.30‰) springs. the amplitude of the observed isotope table 3. minimum, maximum, median, and amplitude values of the δ18o, δ2h and d-excess isotope compositions for vitunj, zagorska mrežnica, dretulja, veliko vrelo, gojak, tounjčica, mrežnica and slunjčica springs, and kapela mt. precipitation. location values δ18o ( ‰) δ2h (‰) d-excess vitunj maximum -10.65 -70.46 15.86 minimum -8.26 -51.83 13.06 median -9.12 -59.52 14.62 amplitude 2.39 18.63 2.80 zagorska mrežnica maximum -10.28 -67.75 15.29 minimum -8.43 -53.39 13.11 median -9.50 -61.92 14.48 amplitude 1.84 14.36 2.18 dretulja maximum -10.60 -70.49 15.46 minimum -9.30 -60.26 13.46 median -10.20 -67.08 14.48 amplitude 1.30 10.22 2.00 veliko vrelo maximum -10.48 -69.10 15.49 minimum -9.07 -57.57 11.96 median -10.10 -66.09 14.69 amplitude 1.41 11.53 3.53 gojak maximum -10.10 -67.40 14.69 minimum -8.01 -50.48 12.84 median -9.26 -60.23 12.84 amplitude 2.08 16.92 1.85 tounjčica maximum -10.51 -70.27 15.06 minimum -8.46 -53.65 12.47 median -9.49 -62.25 13.76 amplitude 2.06 16.62 1.85 mrežnica maximum -10.44 -68.75 15.39 minimum -8.89 -57.23 12.80 median -9.95 -65.69 14.08 amplitude 1.55 11.52 2.58 slunjčica maximum -10.58 -70.38 14.86 minimum -8.78 -55.73 13.16 median -9.94 -65.57 14.15 amplitude 1.80 14.64 1.70 kapela mt. precipitation maximum -12.33 -88.00 18.56 minimum -4.99 -25.55 8.75 median -7.87 -47.52 15.00 amplitude 7.34 62.45 9.81 g eo lo gi a c ro at ic a 134 geologia croatica 77/2 indicates the residence time of water in the aquifer, characterizing the lowest amplitude with the highest homogenization, i.e., the longest retention (clark & fritz, 1997). 5. discussion 5.1. major ion chemistry the chemical composition analysis of spring waters was plotted on a piper diagram (fig. 4) to define their hydrochemical facies. all water samples from the monitored springs exhibited the ca–mg–hco3 hydrogeochemical facies, indicating the dissolution and weathering of carbonates (limestone and dolomite), with no discernible interaction between groundwater and non-carbonate rocks such as evaporites. the spring waters from tounjčica, veliko vrelo, slunjčica, and dretulja displayed a more uniform and clearly defined ca–hco3 facies, while the samples from zagorska mrežnica, vitunj, gojak, and mrežnica showed mixed facies ranging from ca–hco3 to ca– mg–hco3. the ph indicates alkaline waters, which are vital for the dissolution of carbonate rocks within the watershed. the molar mg2+/ca2+ ratio (fig. 5) was used to determine the predominant dissolution of carbonate minerals. in all spring waters, the mg2+/ca2+ ratio indicated the predominant presence of limestone rocks in the study area (fig. 5a). specifically, the calcite dissolution results in water characterized by a mg2+/ ca2+ ratio below 0.1. however, the simultaneous dissolution of calcite and dolomite results in a mg2+/ca2+ ratio of about 0.33. if the mg2+/ca2+ ratio is equal to 1, this indicates that the pure dolomite dissolution is in equilibrium with the water (mayo & loucks, 1995; szramek et al., 2011). the ratio was higher during recession periods and lower during high water conditions in all monitored spring waters (fig. 5b). regardless of hydrological conditions, in the groundwaters of the dretulja, slunjčica, tounjčica, and mainly zagorska mrežnica springs, the mg2+/ca2+ ratio consistently indicates the dissolution of limestone rocks. in contrast, during recession periods in the vitunj, gojak, mrežnica, and veliko vrelo spring waters, the increase in the mg2+/ca2+ ratio was significantly more pronounced. this could be attributed to a higher proportion of dolomite in their respective catchment areas or to the extended water residence time within small aquifer fractures (stroj et al., 2020). the correlation analysis of physico-chemical and chemical parameters, conducted on 258 samples, is presented in table 4. a strong positive correlation was observed between the dominant ca2+ cation and the dominant hco3 – anion, indicating a robust linear relationship. furthermore, the sec showed a strong positive correlation with both ca2+ and hco3 ions, while its correlation with mg2+, cl–, na+, and k+ was weak to moderate. this is attributed to an interaction between the groundwater and mainly limestone. no correlation was present with the no3 – ion. conversely, the no3 – ion displayed a strong positive correlation with so4 2– ions and moderate correlation with cl– and na+ ions, indicating the anthropogenic source of those ions. moreover, na+ ions had a strong positive correlation with cl–, and weak correlation with k+, no3 –, and so4 2–. the temperature values positively correlated with k+ and so4 2– ions. ph did not display any conspicuous correlations with any of the studied parameters. despite the high quality of the spring waters in the study area, with all parameter values falling significantly below their maximum allowable concentrations (mac), there is a figure 4. the piper diagram of hydrochemical facies within the study area. figure 5. the mg2+/ca2+ ratio in monitored springs. g eologia c roatica 135boljat et al.: tracing hydrological processes: insights from hydrochemical and isotopic investigations in the northern part of croatian dinaric karst noticeable anthropogenic impact. the natural sources of sulfates are the dissolution of gypsum and anhydrite, as well as the oxidation of sulfide minerals (fernando et al., 2018; lukač reberski et al., 2009). however, the strong correlation with nitrate (r=0.69) and weak correlation with cl (r=0.17) and k+(r=0.17) and its spatial distribution and seasonal variation indicate human impact, such as inputs from wastewater, agriculture, or fertilizer usage. in general, it can be observed that the concentration of nitrates and sulphates is diluted in all springs during periods of higher water levels, e.g. in february and may as well as november 2019 and october 2020. (fig. 6). the slightly higher sulfate, nitrate, and chloride concentrations are determined in the gojak and tounjčica spring waters, located downstream from the ogulin urban area table 4. pearson correlation analysis of physico-chemical and chemical parameters in the eight karst spring waters in the north dinaric region of croatia. variables t ph ec o2 (mg/l) na+ (mg/l) mg2+ (mg/l) k+ (mg/l) ca2+ (mg/l) cl– (mg/l) no3 – (mg/l) so4 2– (mg/l) hco3 – (mg/l) t 1 ph 0.033 1 ec 0.094 –0.245 1 o2 (mg/l) –0.265 0.016 –0.042 1 na+ (mg/l) 0.243* 0.061 0.234* –0.061 1 mg2+ (mg/l) 0.193 0.009 0.279* 0.086 –0.040 1 k+ (mg/l) 0.330* 0.078 0.197* –0.164 0.473* 0.053 1 ca2+ (mg/l) –0.085 –0.282 0.687 0.012 –0.029 –0.147 0.061 1 cl– (mg/l) 0.184 0.049 0.261* –0.052 0.975 –0.050 0.458* –0.013 1 no3 – (mg/l) 0.166 0.091 –0.053 –0.432 0.313* –0.053 0.145 –0.296 0.346* 1 so4 2– (mg/l) 0.342* –0.024 0.192 –0.364 0.158 0.286* 0.174 –0.171 0.166 0.688 1 hco3 –(mg/l) –0.050 –0.208 0.737 0.088 –0.080 0.262 –0.027 0.643 –0.050 –0.251 –0.005 1 *week correlation figure 6. time series of sulfates, nitrates and chlorides in vitunj, zagorska mrežnica, dretulja, veliko vrelo, gojak, tounjčica, mrežnica and slunjčica spring waters. g eo lo gi a c ro at ic a 136 geologia croatica 77/2 april 2018, likely caused by the impact of melted snow cover on the kapela mt. therefore, samples collected during the hydrograph peaks should be discarded if seasonal variations are considered, as well as in the mean residence time and mean recharge altitude calculations. the precipitation isotope data were plotted in a binary δ18o– δ2h diagram to create the lmwl of kapela mt (fig. 7a) based on three-year series of δ18o and δ2h values, as follows: δ2h = 7.81 δ18o + 13.72 the obtained relationship coincides well with the regional western mediterranean meteoric water line (wmmwl) established by celle-jeanton et al. (2001), suggesting that the air mass has predominant mediterranean sources. calculated d-excess values (fig. 7b) of monthly precipitation mixtures in almost all samples also indicate a predominant origin from the mediterranean air mass, (d-excess value higher than 10‰ taken as a reference as suggested by merlivat & jouzel (1979)). considering the precipitation amount and frequency, only two monthly precipitation samples could be predominantly originating from the atlantic, collected in july 2019 and february 2020 (fig. 7b). monthly values of δ18o and δ2h isotopic composition in spring waters are plotted in figure 8 and compared with the kapela mt. lmwl. the plotted δ values for all springs construct the groundwater lines (gwls). the gwls of the monitored springs conform to the kapela lmwl, veryfing the meteoric origin of groundwater (fig. 8). based on the gwls, we observed two distinct isotopic fingerprints of precipitation influencing the vitunj and and ogulin polje, where agriculture activities are prevalent. in both springs, a slight increase in the chloride content was observed during recession periods. furthermore, three monitoring campaigns determined extremely high concentrations of na+ and cl–, as well as elevated sec values in the tounjčica spring water. while these occurrences in december of 2018 and 2019 could be attributed to road salting practices, it is not the case for august 2018. the data suggests that the cabbage pickling plants, located between the sabljaki lake dam and the southern part of the ogulin city urban area, are within the tounjčica catchment area, and anecdotal evidence suggests overflow from salty water tanks may end up in the underground under certain conditions. in addition, in the springs of tounjčica, unusual movements of dissolved oxygen can be observed, which drops to very low values during the recession periods. hydrogeological relationships do not explain this phenomenon; it is more likely due to the impact of wastewater, particularly water from a wastewater treatment plant situated within the catchment area. 5.2. stable isotopes the isotopic composition of spring waters displays muted seasonal fluctuations in contrast to the isotope composition of precipitation collected at the kapela mt. (fig. 7c). the changes in discharge exerted a stronger influence on the δ18o and δ2h content in spring waters than the seasonal variations. the noticeable enrichment in stable isotopes is observed in two water waves, in december of 2019 and november of 2020, indicating the sampling of spring water with a noteworthy component of freshly infiltrated precipitation. conversely, a noticeable decrease in the isotope content was observed in figure 7. a. local meteoric water line (lmwl) for the kapela mt vs. western mediterranean meteoric water line (wmmwl) (celle-jeanton et al. 2001); b. d-excess of precipitation; c. time series of the isotope composition of a δ18o in monitored springs, compared with precipitation of the ogulin station and discharge data for the mrežnica river station. g eologia c roatica 137boljat et al.: tracing hydrological processes: insights from hydrochemical and isotopic investigations in the northern part of croatian dinaric karst zagorska mrežnica springs vs. the veliko vrelo and dretulja springs. the veliko vrelo and dretulja springs generally have more negative values of δ18o and δ2h than the vitunj and zagorska mrežnica water springs. the gwls of monitored springs across the kapela mt. coincide well with the kapela mt. lmwl showing the lack of precipitation evaporation before infiltration to the subsurface. during periods of elevated water levels, the zagorska mrežnica spring is fed from surface waters originating from flooded poljes in the hinterland (buljan et al., 2019). however, the impact of evaporation is insignificant due to the relatively short duration of flooding and the low temperature, which render the evaporation effect negligible (clark & fritz, 1997). in the second spring zone, the content of stable isotopes in the spring waters follows the trend across kapela mt.; decreasing in heavy isotopes from north to south. in the north, the gojak spring is generally enriched in heavy isotopes in relation to the upstream vitunj spring, which was especially noticeable during the recession period of 2018, indicating a large proportion of water from other directions and the lower immediate hinterland. this corroborates the results of tracer testing linking the gojak spring with sinkholes in the ogulin dobra watercourse (known only from unpublished reports, as the original reports are unavailable). the slope of the tounjčica gwl (fig 8.) indicates a slight evaporation effect in the spring waters, probably caused by a more lengthy atmospheric influence on the spring water, which suggests that sabljaki lake belongs to its catchment area. the mrežnica and gojak springs have interesting, similar gwls, with the same slope and intercept. still, the observed isotope values in mrežnica spring waters have more negative values than those of the gojak spring water. in the southern part of the study area, the δ18o average contents of spring waters exhibited the most negative values in dretulja, followed by the veliko vrelo, mrežnica, and slunjčica springs. the impact of precipitation impoverishment is clearly visible in this area, since the dretulja spring is 110 metres lower in elevation but located 11 kilometres north of the veliko vrelo spring. the dynamic of stable isotopes in spring waters in the south is similar, but seasonal f luctuations depend on hydrological conditions (fig. 7). in the summer of 2018, during the recession period, the water of dretulja spring had a noticeably lower stable isotopic content compared to the veliko vrelo spring. in contrast, differences were relatively minor during the moderate water levels. this observation suggests a greater influx of water into the veliko vrelo spring. the mrežnica and slunjčica springs were enriched in heavy isotopes compared to the upstream veliko vrelo and dretulja springs. possible interpretations of the spatial distribution and general depletion of the stable isotope content from north to south can be interpreted as follows: (1) the precipitation continental effect (kern et al., 2020; mezga et al., 2014), (2) the more significant influence of the atlantic air mass, evident in the neighbouring area of plitvice lake (babinka, 2008), (3) the potential impact of lake water evaporation on precipitation composition (hunjak, 2015). although the calculated gradients for the continental effect in the adriaticpannonian region are much lower than those observed in this area (kern et al., 2020); it is essential to consider the significant altitude effect caused by the rugged terrain. in the south, the mediterranean air masses must cross the velebit mt., with a peak of 1754 m a.s.l, before reaching the kapela mt., or ~ 60 km to the catchment areas of dretulja and veliko vrelo. conversely, in the north, the kapela mt. is the first significant barrier for mediterranean air masses, affecting the catchment areas of vitunj and zagorska mrežnica, with an aerial distance to the adriatic coast of ~20 km. in addition, the d-excess value depends on humidity, sea temperature, and wind speed during primary evaporation (or geographic location of forming air masses). the three-year data set reveals figure 8. correlation diagram of δ18o and δ2h values and groundwater lines for four springs in the first spring zone, situated at the foot of the kapela mt (a), and four springs in the second spring zone situated in the shallow karst zone (b). g eo lo gi a c ro at ic a 138 geologia croatica 77/2 average d-excess values ranging between 14.48 and 14.69 in aquifers within the kapela mt., or in the spring water of the first spring zone. conversely, in the second spring zone, the d-excess values range from 13.72 to 14.15 (fig. 9, table 3). the calculated d-excess values are very similar in the observed groundwater and undoubtedly suggest the spring being fed predominantly from the mediterranean air masses. slightly lower values were expected in the second spring zone, as its immediate catchment area is located on the ne side of kapela mt. the mountain obstructs air masses with a lower d-excess coming from the north, which are emptied before crossing the mountain range. similar d-excess values were calculated for the plitvice lakes area (hunjak, 2015), but with a different interpretation emphasizing the impact of lake water evaporation on precipitation composition. a detailed interpretation of the origin of the precipitation origin is beyond the scope of this research. however, the authors lead towards understanding the intricate interplay between the influence of relief and continental effect on the isotopic signatures observed in the region (fig. 10). the stable isotopes and spring water temperature are widely recognized natural tracers for assessing groundwater's origin, retention time, and dynamics. higher groundwater residence times result in greater homogenisation of the observed parameters (clark & fritz, 1997). to estimate groundwater mean residence times (mrt) and elevation of the recharge area, only δ18o values are considered due to the strong correlation between δ18o and δ2h values (r >0.96) (fig.8) 5.3. estimation of the groundwater mean residence times in determining mrts, it is crucial to be careful due to established variations in spring gwls caused by differences in the composition of stable isotopes in precipitation. however, figure 9. the box plots of the d-excess values observed in monitored spring waters. figure 10. interplay between relief and continental effect on depletion of the δ18o and δ2h composition across the north dinaric karst region. g eologia c roatica 139boljat et al.: tracing hydrological processes: insights from hydrochemical and isotopic investigations in the northern part of croatian dinaric karst given that the precipitation sampler was situated in the middle of the study area, the mrts could be calculated since the calculation does not consider absolute but relative values (eq. 1). the mrts of groundwater were determined based on equation 1 using the amplitudes of δ18o isotopes in pre cipi tation as input data and amplitudes of spring waters as output data, (without extreme values caused by a single event and assumed high proportion of freshly infiltrated water). the data in table 5 represent the average mrt values of three calculations, one per monitored year. the mrt for monitored springs is between 9 and 16 months (table 5), indicating a system with significantly low storage capacity, similar to the nearby regions in the dinaric karst: in northern velebit ≤ 1 year (paar et al., 2019); in postojna, the established mrt in the systems was 7 months to 10 years (mandić, et al., 2013); in the catchment area of plitvice lakes 1.3–2.9 year (meaški, 2011). the mrt for the water that drains kapela mt. (in the aquifers of vitunj, zagorska mrežnica, veliko vrelo, and dretulja springs) was ascertained over one year, and the established average retention of water in aquifers in shallow karst area is for less than one year. the temperature fluctuations are correlated with the obtained values in spring waters as a water retention indicator. the pronounced temperature fluctuation in the water of the zagorska mrežnica springs may be attributed to the recharge of spring with water from flooded poljes during high water conditions (fig.3). 5.4. estimation of the mean recharge altitude the precipitation isotope content is linearly depleted with increasing altitude due to the water's physical characteristics, known as the altitude effect, meaning that spring waters fed from higher altitudes are more depleted in heavy isotopes (clark & fritz, 1997). in the study area, anomalies are detected by comparing the isotopic content in spring water (fig.11b.). based on the mean δ18o value, the tounjčica and gojak catchment areas are situated at higher elevations compared to the upstream zagorska mrežnica and vitunj springs within their respective catchment areas. the obtained data indicates the impact of evaporation from surface waters within the immediate catchment of springs and the intake from other directions in the gojak spring. furthermore, geomorphology attributed to mean spring temperature data contradicts the isotope data's assertion that the dretulja catchment area is at a higher elevation than the veliko vrelo watershed. (fig. 11 a). these anomalies are in line with the interpreted continental effect (fig. 10). therefore, the spring's mra is determined based on the mean spring water temperature as a reliable indicator and compared with isotope content. the spring water temperature reflects the annual air temperature of the spring catchment area. vertical temperature gradients in continental croatia, including the study area, amount to 0.5°c/100 m (zaninović et al., 2008). therefore, based on water temperature, the mra of the monitored springs spreads within 710 metres from the lowest positioned catchment area of gojak to the highest table 5. average recharge altitudes and mean residence times for the monitored springs. spring average recharge altitude (m a.s.l.) average temperature (3-year data set) mean residence times (month) δ18o amplitude (‰) temperature amplitude (°c) vitunj 1080 7.9 16 0.81 1.8 (1.2*) zagorska mrežnica 840 8.9 15 0.83 2.3 dretulja 840 8.9 13 0.97 1.6 veliko vrelo 1120 7.7 12 1.19 1.7 (1.4*) gojak 400 11.1 10 1.25 9.2 tounjčica 660 9.8 13 0.97 9.2 mrežnica 440 9.9 11 1.12 7.3 slunjčica 680 9.7 9 1.32 2.2 *the amplitude without two measurements in the highest hydrogram peaks figure 11. the mean spring water temperature vs. springs' elevation (a), the δ18o value vs. springs' elevation (b). g eo lo gi a c ro at ic a 140 geologia croatica 77/2 situated at veliko vrelo. the lowest elevation of the gojak catchment area corresponds to the previously mentioned northward connection. according to the morphological characteristics, the estimated mean recharge altitude of the gojak catchment is approximately 400 m a.l.s. the springs mra in shallow karst areas of tounjčica, mrežnica, and slunjčica, extends to ~640–680 m a.s.l. in the kapela mt, the zagorska mrežnica and dretulja springs feed from similar average altitudes ~840 m a.s.l, as well as the vitunj and veliko vrelo springs ~1080–1120 m a.s.l. 6. conclusion here, the hydrochemical and isotopic fingerprints have been used to gain insight into the highly karstified aquifers situated across kapela mt. these aquifers play a pivotal role in the provision of drinking water within the region. the study area comprises two spring zones: the first one is represented by four springs located at the foot of kapela mt., with the vitunj spring to the north, and zagorska mrežnica, dretulja, and veliko vrelo spings to the south. the second spring zone is represented by the gojak, tounjčica, mrežnica, and slunjčica springs. the results of major ion analysis reveal a monolithological drainage basin. all eight springs exhibit calcium–hydrogen carbonate (ca–hco3) to calcium-magnesium hydrogen carbonate (ca–mg–hco3) hydrochemical facies, indicating the dissolution and weathering of carbonates (limestone and dolomite), with the absence of evaporites and other noncarbonate rocks. from the mg2+/ca2+ ratio and the piper diagram, we observed a higher proportion of dolomite component in the vitunj and gojak springs which belong to the dobra river catchment, and in the veliko vrelo and mrežnica spring waters. groundwater mineralization generally increases from the north to the south of the area, with the lowest mineralization observed in the vitunj spring and the highest in the dretunja and veliko vrelo springs. the concentrations of nitrates, sulfates, and chlorides are low, indicating the relatively unpolluted quality of the groundwater, but the human impact is still observed in the gojak and tounjčica springs located downstream from the urban area and ogulin polje. although the observed concentrations are not alarming, it is crucial to consider the aquifers' high vulnerability when planning the spatial development of the region. the new lmwl calculated for kapela mt. based on a three-year dataset (june 2018 – may 2021) can be used as a background for investigating precipitation, groundwater, and surface water origin and their interrelationships. from the new lmwl we observed a predominant origin of precipitation from the mediterranean air mass regardless of the season, in contrast to earlier studies which suggested a much more significant inf luence of atlantic air masses on winter precipitation in the neighbouring areas. the isotopic composition of spring waters indicates the meteoric origin of groundwater, rapid dynamics, and a mean residence time in the aquifer of up to 1.5 years. the seasonal fluctuations of isotopic composition are muted in spring waters due to water mixing in the subsurface. however, all calculated d-excess values in the monthly spring samples indicate a dominant reach from the mediterranean air masses. based on the spatial distribution of monitored springs, a significant continental (altitude) effect is detected on the isotopic composition of spring waters in the southern area, which are depleted of the heavier isotopes. the air masses from the mediterranean have to cross velebit mt. and several smaller massifs to the dretulja and veliko vrelo catchment areas. on that path, the heavier isotopes are broken down by the high mountain’s obstruction of the air masses, resulting in depletion of the δ18o and δ2h in the groundwaters. due to the significant enrichment of stable isotopes from south to north, the mean recharge altitude calculation based on stable isotopes is not applicable in the study area. the mra was calculated based on the average spring water temperature as a reliable indicator, the mra of the monitored springs ranges over 710 metres from the lowest positioned catchment area of gojak to the highest situated at veliko vrelo. acknowledgement the authors express their gratitude to the croatian meteorological and hydrological service and the croatian electric power company for the provided data. this work was financially supported by interreg danube camaro-d project co-funded by the european regional development fund, project b2z30-76/19 funded by the croatian electric power company, and nona project funded by the national recovery and resilience plan 2021–2026 of the european union – nextgenerationeu, and monitored by the ministry of science and education of the republic of croatia. the field investigations and analysis were funded and supported by the croatian geological survey, department of hydrogeology and engineering geology. references akter, s. & ahmed, k.r. (2019) water chemistry and water quality of a tidal river system in relation with riverbank land use pattern and regional climate in the southwest bengal delta of bangladesh.– sustain. water resour. manag. 5, 1259–1279. doi: 10.1007/s40899-019-00308-3 appelo, c.a.j & postma, d. (1994): geochemistry, groundwater and pollution.– balkema, rotterdam, 536 p. babinka, s. (2007): multi-tracer study of karst waters and lake sediments in croatia and bosnia and herzegovina: plitvice lakes national park and bihać area.– doctoral thesis, universität bonn, 168 p., bonn. babinka, s. (2008): environmental isotopes as a tool for hydrological characterisation of karsta aquifer , groundwater protection and estimation of groundwater reserves – case study: plitvice lakes and bihać area.– in: savjetovanje hidrološka mjerenja i obrada podataka, nacionalni park plitvička jezera, 232–255. bahun, s. (1968): geološka osnova hidrogeoloških odnosa krškog područja između slunja i vrbovskog (geological basis of the hydrogeological relations in the karst area between slunj and vrbovsko).– geološki vjesnik, 21, 19–82. biondić, b., biondić, r. & kapelj, s. (2006): karst groundwater protection in the kupa river catchment area and sustainable development.– environ. geol., 2006, 49/6, 828–839. doi: 10.1007/s00254-006-0178-4 biondić, b., biondić, r. & meaški, h. (2010): the conceptual hydrogeological model of the plitvice lakes.– geol croat, 63/2, 195 – 206. doi: 10.4154/gc.2010.17 biondić, r. (2013): zones of sanitary protection of springs in the ogulin area (in croatian).– unpublished, the archive of university of zagreb, faculty of geotechnical engineering. biondić, r., meaški, h., biondić, b. & loborec, j. (2021): karst aquifer vulnerability assessment (kava) method – a novel gis-based g eologia c roatica 141boljat et al.: tracing hydrological processes: insights from hydrochemical and isotopic investigations in the northern part of croatian dinaric karst method for deep karst aquifers.– sustainability, 13/6, 3325, 20. doi: 10.3390/su13063325 bočić, n. (2003): relation between karst and fluviokarst relief on the slunj plateau (croatia).– acta carsologica, 32/2, 11, 137–146. doi: 10.3986/ ac.v32i2.343 bočić, n., pahernik, m. & mihevc, a. (2015): geomorphological significance of the palaeodrainage network on a karst plateau: the una– korana plateau, dinaric karst, croatia.– geomorphology, 247, 55–65. doi: 10.1016/j.geomorph.2015.01.028 bočić, n., pahernik, m. & maradin, m. (2016): temeljna geomorfološka obilježja karlovačke županije.– prirodoslovlje, 16/1–2, 153–172. bonacci, o. & andrić, i. (2010): impact of an inter‐basin water transfer and reservoir operation on a karst open streamflow hydrological regime: an example from the dinaric karst (croatia).– hydrol process, 24/26, 3852–3863. doi: 10.1002/hyp.7817 brkić, ž., kuhta, m., hunjak, t. & larva, o. (2020): regional isotopic signatures of groundwater in croatia.– water, 12, 1983. doi: 10.3390/w12071983 bukovac, j., šušnjar, m., poljak, m. & čakalo, m. (1983): osnovna geološka karta 1:100 000, list črnomelj [(basic geological map scale 1:100.000 sheet črnomelj), l 33 – 91].– geološki zavod zagreb i geološki zavod ljubljana, savezni geološki zavod, beograd, 63 p. buljan, r., pavlić, k., terzić, j. & perković, d. (2019): a conceptual model of groundwater dynamics in the catchment area of the zagorska mrežnica spring, the karst massif of kapela mountain.– water, 11/10. doi: 10.3390/w11101983 clark, m., fan, y., lawrence, d.m., adam, j.c., bolster, d., gochis, d., hooper, r., kumar, m., leung, l.r., mackay, d.s., maxwell, r.m., shen, c., swenson, s.c. & zeng, x. (2015): improving the representation of hydrologic processes in earth system models.– water resources research, 51, 5929–5956. doi:10.1002/ 2015wr017096 clark, i. & fritz, p. (1997): environmental isotopes in hydrogeology.– lewis, 328 p. craig, h. (1961a): isotopic variations in meteoric waters.– science, 133, 1702 – 1703. doi: 10.1126/science.133.3465.1702 celle-jeanton. h., travi. y. & blavoux. b. (2001): isotopic typology of the precipitation in the western mediterranean region at three different time scales.– geophysical research letters, 28, 1215–1218. doi:10.1029/2000gl012407 croatian parliament (2008): water management strategy.– official gazette of croatia, zagreb, 91 p. čanjevac, i.,martinić, i., radišić, m., rubinić, j. & meaški, h. (2023): hydrology, hydrogeology and hydromorphology of the plitvice lakes area, plitvice lakes.– in: miliša, m. & ivković, m. (eds): plitvice lakes. springer water. springer, cham., 17–64. doi: 10.1007/9783-031-20378-7_2 dansgaard, w. (1964): stable isotopes in precipitation.– tellus, 16, 436–468. doi: 10.1111/j.2153-3490.1964.tb00181.x domenico, p.a. & schwartz. f.w. (1990): physical and chemical hydrogeology.– john willey and sons, new york, 824 p. dragičević, i. & velić, i. (2002): the northeastern margin of the adriatic carbonate platform.– geologia croatica, 55/2, 185–232. fernando. w.a.m., ilankoon. i., syed. t.h. & yellishetty. m. (2018): challenges and opportunities in the removal of sulphate ions in contaminated mine water: a review.– miner. eng., 117, 74–90. doi: 10.1016/j.mineng.2017.12.004 fiket, ž., furdek turk m., ivanić, m. & kniewald , g. (2021): non-traditional stable isotope signatures in geological matrices as a tool for interpreting environmental changes – a review. – geol. croat., 74/2, 177–187. doi: 10.4154/gc.2021.12 frančišković-bilinski, s., cuculić, v., bilinski, h., häusler, h. & stadler, p. (2013): geochemical and stable isotopic variability within two rivers rising under the same mountain, but belonging to two distant watersheds.– chemie der erde, geochemistry, 73/3, 293–308. doi: 10.1016/j.chemer.2013.02.004 freedman, d., pisani, r., & purves, r. (2007): statistics (international student edition).– ww norton &amp company, new york. ford, d. & williams, p. (2007): karst hydrogeology, in: karst hydrogeology and geomorphology.– john wiley & sons ltd, 103–144. doi: 10.1002/9781118684986.ch5 gibbs r.j. (1970): mechanisms controlling world water chemistry.– science, 170, 1088–1090. doi: 10.1126/science.170.3962.1088 gladović, d., parlov, j., peroković, d., nakić, z. & kovač, z. (2023): the role of slope inclination, doline density and water budget analysis in delineation of complex karst catchment area of slunjčica river (croatia).– geofizika, 40. doi: 10.15233/gfz.2023.40.1 hunjak, t. (2015): spatial distribution of oxygen and hydrogen stable isotopes from precipitation in croatia.– unpubl. phd thesis, university of zagreb, 75 p. hunjak, t., lutz, h. o. & roller-lutz, z. (2013): stable isotope composition of the meteoric precipitation in croatia.– isot. environ. healt s., 49/3, 336–345. doi: 10.1080/10256016.2013.816697 kern, z., hatvani, i.g., czuppon, g., fórizs, i., erdélyi, d., kanduč, t., palcsu, l. & vreča, p. (2020): isotopic ‘altitude’ and ‘continental’ effects in modern precipitation across the adriatic–pannonian region.– water, 12, 1797. doi: 10.3390/w12061797 korolija, b., živaljević, t. & šimunić, a. (1980): osnovna geološka karta sfrj 1: 100.000: list slunj [basic geological map of sfry: sheet slunj].– savezni geološki zavod, beograd korbar, t. (2009): orogenic evolution of the external dinarides in the ne adriatic region: a model constrained by tectonostratigraphy of upper cretaceous to paleogene carbonates.– earth-sci. rev., 96, 296–312. doi: 10.1016/j.earscirev.2009.07.004 kovačević, a. (2005): hydrogeological features of karlovac county.– unpubl. master thesis, faculty of mining, geology and petroleum engineering, department of geology and geological engineering, university of zagreb, croatia, 126 p. kralik, m. (2015): how to estimate mean residence times of groundwater.– proced earth plan. sc., 13, 301–306. doi: 10.1016/j.proeps.2015.07.070 lukač reberski, j., kapelj, s. & terzić j. (2009): an estimation of groundwater type and origin of the complex karst catchment using hydrological and hydrogeochemical parameters: a case study of the gacka river springs.– geologia croatica, 62/3, 157–178. doi: 10.4154/gc.2009.14 lukač reberski, j., marković, t. & nakić z. (2013): definition of the river gacka springs subcatchment areas on the basis of hydrogeological parameters.– geologia croatica, 66/2, 39–53. doi: 10.4154/ bc.20i3.04 małoszewski, p., rauert, w., stichler, w., herrmann, a. (1983): application of flow models in an alpine catchment area using tritium and deuterium data.– journal of hydrology, 66, 1–4, 319–330. doi: 10.1016/0022-1694(83)90193-2 mance, d., radišić, m., lenac, d. & rubinić, j. (2022): hydrological behavior of karst systems identified by statistical analyses of stable isotope monitoring results.– hydrology, 9, 82. doi: 10.3390/hydrology9050082 mandić, m., mihevc, a., leis, a., lojen, s. & krajcar bronic, i. (2013): mean residence time of drip water in postojna cave, slovenia. in: 3rd international conference "waters in sensitive & protected areas". zagreb, croatia, 171–174. mandel., s. & shiftan., z.l. (1981): groundwater resources: investigation and development.– academic press, new york, 269 p. mandić, m., bojić, d., roller lutz, z., lutz, h. & bronić krajcar, i. (2008): note on the spring region of gacka river (croatia).– isot. environ. health stud., 44, 201–208. marković, t.,sladović, ž., domitrović, d., karlović, i. & larva, o. (2022): current utilization and hydrochemical characteristics of geothermal aquifers in the bjelovar sub-depression.– geol. croat., 75/2, 223-233. doi: 10.4154/gc.2022.21 mayo a.l. & loucks m.d. (1995): solute and isotopic geochemistry and ground water flow in the central wasatch range, utah.– journal of hydrology, 172/1, 31–59. doi: 10.1016/0022-1694(95)02748-e g eo lo gi a c ro at ic a 142 geologia croatica 77/2 mcguire, k. & mcdonnell, j. (2006): a review and evaluation of catchment transit time modeling.– journal of hydrology, 330, doi: 10.1016/j.jhydrol.2006.04.020 mezga, k., urbanc, j. & cerar, s. (2014): the isotope altitude effect reflected in groundwater: a case study from slovenia.– isot. environ. healt s., 50/1, 33–51, doi: 10.1080/10256016.2013.826213 meaški, h. (2011): model of the karst water resources protection on the example of the plitvice lakes national park [in croatian].– unpubl. phd thesis, faculty of mining, geology and petroleum engineering, university of zagreb, 211 p. meaški, h., marciuš, m. & ptiček siročić, a. (2016): hidrogeološke značajke vodotoka plitvica na području plitvičkih jezera, hrvatska.– environmental engineering = inženjerstvo okoliša, 3, 21–32. merlivat, l. & jouzel, j. (1979): global climatic interpretation of the deuterium-oxygen 18 relationship for precipitation.– j. geophys. res, 84, 5029 – 5033 meybeck, m. (1987): global chemical weathering of surficial rocks estimated from river dissolved loads.– am. j. sci., 287, 401–428. doi: 10.2475/ ajs.287.5.401 michelsen, n., geldern, v.r., roßmann, y., bauer, i., schulz, s., barth, j.a.c. & schüth, c.(2018): comparison of precipitation collectors used in isotope hydrology.– chemical geology, 488, 171–179. doi:10.1016/j.chemgeo.2018.04.032 milanović, s., vasić, l., petrović, b., dašić, t., marinović, v. & vojnović, p. (2023): the impact on karst aquifer regimes induced by a surface reservoir in karst through multiparametric analyses (reservoir bileća – herzegovina).– sustainability, 15, 11968. https://doi. org/10.3390/su151511968 mohammed, n., celle-jeanton, h., huneau f., le coustumer, p., lavastre, v., bertrand, g., charrier, g. & clauzet, m.l. (2014): isotopic and geochemical identification of main groundwater supply sources to an alluvial aquifer, the allier river valley (france).– j hydrol., 508, 181–196. doi: 10.1016/j.jhydrol.2013.10.051 paar, d., mance, d., stroj, a. & pavić, m. (2019): northern velebit (croatia) karst hydrological system: results of a preliminary 2h and 18o stable isotope study.– geol. croat., 72/3, 205–213. doi: 10.4154/gc.2019.15 palmer, a.n. (2010): understanding the hydrology of karst.– geol. croat., 63/2, 143–148. doi: 10.4154/gc.2010.11 pavlić, k. & parlov, j. (2019): crosscorrelation and cross-spectral analysis of the hydrographs in the northern part of the dinaric karst of croatia.– geosciences; 9/2, 86 p. doi: 10.3390/geosciences9020086 piper, a.m. (1944): a graphic procedure in the geochemical interpretation of water-analyses.– trans. am. geophys. union, 25, 914–928. doi: 10.1029/tr025i006p00914 rodgers, p., soulsby, c., waldron, s. & tetzlaf, d. (2005): using stable isotope tracers to assess hydrological flow paths, residence times and landscape influences in a nested mesoscale catchment.– hydrology and earth system sciences, 9, 139–155. doi:10.5194/hess-9-139-2005 savić, d. & dozet, s. (1983): osnovna geološka karta sfrj 1: 100.000: list delnice [(basic geological map of sfry, sheet delnice) l 33–90]. – geološki zavod; oour za geologiju i paleontologiju, zagreb; geološki zavod, ljubljana (1970.–1983.); savezni geološki institut, beograd. schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine-carpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss j. geosci., 101, 139–183. doi: 10.1007/s00015-008-1247-3 stevanovic, z., krešić, n., & kukuric, n. (2016): karst without boundaries (1st ed.).– crc press. doi: 10.1201/b21380 stroj, a., briški, m., lukač reberski, j. & frangen, t. (2023): regional analysis of tracer tests in the karstic basin of the gacka river (croatian dinaric karst).– hydrology, 10, 106. doi: 10.3390/hydrology10050106 stroj, a., briški, m. & oštrić, m. (2020): study of groundwater flow properties in a karst system by coupled analysis of diverse environmental tracers and discharge dynamics.– water, 12/9, 2442. doi: 10.3390/w12092442 stroj, a. & paar, d. (2019): water and air dynamics within a deep vadose zone of a karst massif: observations from the lukina jama–trojama cave system (−1,431 m) in dinaric karst (croatia).– hydrol process, 33, 551–561. doi: 10.1002/hyp.13342 szramek, k., walter, l., kanduč, t. & ogrinc, n. (2011): dolomite versus calcite weathering in hydrogeochemically diverse watersheds established on bedded carbonates (sava and soča rivers, slovenia).– aquatic geochemistry, 17, 357–396. doi: 10.1007/s10498-011-9125-4 šušnjar, m., bukovac, j., nikler, l., crnolatac, i., milan., a., šikić, d., grimani, i., vulić, ž. & blašković, i. (1970): osnovna geološka karta sfrj 1:100.000: list crikvenica [basic geological map of sfry, sheet crikvenica, l 33–102].– inst. geol. istraž. zagreb, 1970., sav. geol. zavod beograd. tari, v. (2002): evolution of the northern and western dinarides: a tectonostratigraphic approach.– stephan mueller spec. publ. 1, eur. geosci. union, 1, 223–236. terzić j., stroj, a. & frangen, t. (2012): hydrogeological investigation of karst system properties by common use of diverse methods: a case study of lička jesenica springs in dinaric karst of croatia.– hydrological processes, 26/21, 3302–3311. doi: 10.1002/hyp.9194 terzić, j., marković, t. & lukač reberski, j. (2014): hydrogeological properties of a complex dinaric karst catchment: miljacka spring case study.– environ. earth., sci, 72, 1129–1142. doi: 10.1007/s12665013-3031-6 torkar, a. & brenčič, m. (2015): spatio-temporal distribution of discharges in the radovna river valley at low water conditions.– geologija, 58/1, 47–55. doi: 10.5474/geologija.2015.003 torresan, f., fabbri, p., piccinini, l., libera, n. d., pola, m. & zampieri, d. (2020): defining the hydrogeological behavior of karst springs through an integrated analysis: a case study in the berici mountains area (vicenza, ne italy).– hydrogeol. j., 28, 1229–1247. doi: 10.1007/s10040-020-02122-0 unknown author (1948): basic project of dobra-mrežnica, hydrological substrata; trecer tests, engineering project institute, zagreb, (in croatian). osnovni projekt dobra-mrežnica, hidrološke podloge; bojadisanje ponornica, inženjerski projektni zavod, zagreb. vasić, l., milanović, s., stevanović, z. & palcsu, l. (2020): definition of groundwater genesis and circulation conditions of the complex hydrogeological karst system mlava–belosavac–belosavac-2 (eastern serbia).– carbonate evaporite, 35, 16 p. doi: 10.1007/s13146-020-00550-3 velić, i., bahun, s., sokač, b. & galović, i. (1974): osnovna geološka karta sfrj, list otočac 1:100 000, l 33–115; [basic geological map sfrj, sheet otočac 1:100 000].– institute of geology zagreb, federal institute of geology, beograd. velić, i. & sokač, b. (1982): basic geological map of the republic of croatia 1:100.000; sheet ogulin.– croatian geological survey, zagreb, croatia. velić, i. (2007): stratigraphy and palaeobiogeography of mesozoic benthic foraminifera of the karst dinarides (se europe) – part 1..– geol. croat., 60/1, 1–60. vlahović, i., tišljar, j., velić, i. & matičec, d (2005): evolution of the adriatic carbonate platform: palaeogeography. main events and depositional dynamics.– palaeogeography, paleoclimatology, palaeoecology, 220, 333–360. doi: 10.1016/j.palaeo.2005.01.011 vreča, p., brenčič, m. & leis, a. (2007): comparison of monthly and daily isotopic composition of precipitation in the coastal area of slovenia.– isot. environ. health stud., 43, 307–321. doi: 10.1080/10256010701702739 zaninović, k., srnec, l. & perčec-tadić, m. (2004): digitalna godišnja temperaturna karta hrvatske [digital map of the air temperature in croatia].– hrvatski meteorološki časopis, 39, 51–58. zaninović, k., gajić-capka, m., perčec tadić, m. & vučetić, m. (2008): klimatski atlas hrvatske = climate atlas of croatia 1961–1990. –državni hidrometeorološki zavod: zagreb. g eologia c roatica 143boljat et al.: tracing hydrological processes: insights from hydrochemical and isotopic investigations in the northern part of croatian dinaric karst supplement 1. – the karst springs at the foot of the kapela mountain the vitunj spring during high (a) and low water conditions (a'); the zagorska mrežnica spring during high (b) and low water conditions (b'); the dretulja spring during high (c) and low water conditions (c'); the veliko vrelo spring during high (d) and low water conditions (d') g eo lo gi a c ro at ic a 144 geologia croatica 77/2 supplement 2. – the main karst springs of the kordun rivers the gojak spring during high (a) and low water conditions (a'); the tounjčica spring during high (b) and low water conditions (b'); the mrežnica spring during high (c) and low water conditions (c'); the slunjčica spring during high (d) and low water conditions (d') 2023 | 76/3 | 113–129 | 12 figs. | 7 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction globally, loess is a homogeneous rock concerning its sedimentological properties, geochemical and mineral composition. geomorphologically, it is mostly found today on plateaus (mainly on river terraces) or on gentle slopes. the spatial distribution of palaeosols intercalated in the loess indicates a similar topography during the pleistocene as it is in the present. generally, the surface was covered by steppe during the cold periodes and by forest during the warm periods (bronger, 2003). local differences in the mineralogical composition of loess/palaeosol sections in eastern croatia were established (galović & peh, 2016). they were a consequence of the different source areas of aeolian material. loess/palaeosol successions, as a record of climatic changes, have been investigated in the area of eastern croatia since the end of the 19th century (pilar, 1875; gorjanović-kramber ger, 1911, 1922; šandor, 1912) and are still the focus of investigation (galović et al., 2009, 2011; galović, 2014, 2016; galović & peh, 2016). jenny (1941) defined five factors influencing pedogenesis: climate, organisms, parent material, relief and time. analyzing available factors and minorizing their variations could give us an insight into the length and intensity of warming periods during the pleistocene. evidence and mineralogical and physico-chemical properties of chernozem and chernozem-like soils in croatia lidija galović1, stjepan husnjak2, ajka šorša1 and jasmina martinčević lazar1,* 1 croatian geological survey, sachsova 2, zagreb, croatia; (*corresponding author: jmartincevic@hgi-cgs.hr) 2 university of zagreb, faculty of agriculture, svetošimunska 25, 10000 zagreb, croatia doi: 10.4154/gc.2023.08 abstract the aim was to determine possible local differences between the parent materials of recent leoss-derived soils in eastern croatia (dalj, zmajevac). furthermore, it highlights the existence of chernozem and chernozem-like soils in croatia and describes their basic physical, chemical and mineral properties. for this purpose, two soil profiles (p-3 and p-6) south of the dalj settlement and one soil profile (p-10) near the zmajevac settlement were excavated. the investigation included a detailed pedological analysis, a modal analysis of the heavy and light mineral fraction and a mineralogical analysis of bulk samples (the < 2 mm fraction) and the fraction < 2 µm. by comparing the obtained results with the criteria of the croatian soil classification and the world reference base for soil resources, the soil profiles p-3 and p-6 can be defined as chernozem on loess or hortic calcic chernozem (epiloamic, endosiltic, aric, humic). the systematic unit for profile p-10 was defined as rendzina according to the croatian soil classification or calcic chernozem (siltic) according to the wrb. based on the results of the pedological analysis of the soil profile horizons, a gradual degradation of the chernozem was observed as a result of anthropogenic influence, but also due to recent climate change. the degradation is particularly evident in the form of a reduction in organic matter and the relocation of carbonates from the surface to deeper zones. due to the increasing degree of weathering caused by recent climate changes, some differences in the mineralogical composition of the studied soils were also observed. the progressive degradation of the chernozem due to the effects of recent weathering processes is indicated mainly by the presence of goethite in the fraction < 2 µm as a weathering product of iron minerals (magnetite, pyroxenes…). although the parent material of all three profiles is loess sediments, the reason why the soil material of profile p-10 has not developed a chernic horizon is the constant contribution of aeolian material and a short period of exposure to pedogenetic processes. the scope of this work is, through detailed pedological and mineralogical analyzes, to establish possible local differences in the parent materials of the recent leoss-derived soils. the soil profiles are located on a plain to avoid differences caused by relief. since the organisms present in the soil depend on the prevailing climate, the type of mineralogical composition of palaeosol that developed during warming is a function of time and climate (galović & peh, in press). according to dokuchaev, the chernozems were defined as steppe soils. their pedogenesis was mainly characterised by the soil-forming factors of the dry continental climate, steppe vegetation and loess as a carbonaceous parent material (dokuchaev, 1948). it is generally assumed that his definition, although referring to russian soils, can be generally applied to eastern and central europe. in publications dealing with the problem of chernozem in central europe, its existence in croatia is usually not mentioned (e.g., nejgebauer, 1983; eckmeier et al., 2007; łabaz et al., 2018, 2022). however, according to the soil classification formerly used in croatia (originally the classification of soils of yugoslavia, škorić et al., 1973, 1985) and the croatian soil classification (csc) (husnjak, 2014), chernozem occurs in croatia. the reason for the rare mention is probably that it is a relatively small area and has not been reserched and worked on article history: manuscript received may 02, 2023 revised manuscript accepted august 21, 2023 available online october 16, 2023 keywords: chernozem, loess-derived soils, soil mineralogy, eastern croatia mailto:jmartincevic@hgi-cgs.hr g eo lo gi a c ro at ic a geologia croatica 76/3114 for more than 60 years. in fact, the chernozem soil type occupies an area of only about 50,000 ha in croatia (bogunović et al., 1988; husnjak, 2014). about 95% of the chernozem soil has long been used as arable land in intensive agriculture and the remaining 5% is mainly anthropogenic grassland. the presence of chernozem in croatia according to the national soil classification is also mentioned by other authors but without detailed research (gračanin, 1951; škorić, 1960; ćirić, 1965; škorić et al., 1977; bogunović et al. 1998; špoljar et al. 2001; bašić, 2013; pernar, 2017). it is common knowledge that the most important type of soil for food production in the world is chernozem. therefore, it has been used in agriculture for a long time both globally and in croatia (nejgebauer, 1951; škorić, 1960; škorić et al., 1977; altermann et al., 2005; husnjak, 2014; poznaik, 2019). chernozem is considered one of the most fertile agricultural soils in the world. consequently, chernozem is one of the most useful soils for agriculture and contributes to high agricultural yields. furthermore, in croatia, where chernozem occurs, there are other soils that are very similar to chernozem, but which, according to csc, do not meet the criterion of the depth of the a horizon (> 40 cm) to be classified as chernozem. therefore, we would like to point out the existence of chernozem and chernozem-like soils in croatia and the basic physical, chemical and mineral properties of these soils. the results of this research will be the starting point for the correlation of modern pedogenesis (as a reflection of modern climate) with palaeopedogenesis (as a reflection of palaeoclimate). this will significantly facilitate the palaeoclimatic reconstruction of the warming periods recorded in the loess/palaeosol sequences during the pleistocene at the local level. 1.1. geological and geographical setting quaternary sediments are widespread in eastern croatia and include alluvial, marsh and lake sediments, often covered by aeolian silt-rich loess sediments formed during the pleistocene cold periods (fig. 1a). an area with extensive loess thickness is located in the “loess plateau” in eastern croatia. the dalj profiles are located in the east, and the zmajevac profile is located in the northeast of eastern croatia. in the baranja area, neotectonic movements uplifted the bansko brdo, exposing loess-palaeosol sequences up to 30 m thick on the south-eastern edge of the hill (hećimović, 1991), where a microlocation of the zmajevac profile is located (fig. 1b). in the croatian lowlands, aeolian sediments were deposited in lakes, ponds and shallow swamps during the quaternary (bačani et al., 1999) until they were infilled. then aeolian sedimentation continued and loess sessu stricto formed (bačani et al., 1999; galović et al., 2009). some of these sediments were eroded by the danube, drava and sava ri vers and/or redeposited further downstream as alluvial sediments. similar deposits have been reported and studied from the abony section in hungary (frechen & pécsi, 2004). the microlocation of the dalj profiles is in the croatian lowlands near the bank of the danube. the climate of the region is continental and the annual rainfall is about 700 mm (jelić & kalogjera, 2002). three analyzed profiles are located in the area, which is characterized by a temperate continental climate with dry summers (peel et al., 2007). the area is known as the driest part of the country and differs from central and western croatia which is influenced by continental climate (perčec et al., 2023). nw and ne winds prevail at both sites. the mean annual wind speed is 4.6-4.8 ms–1 (croatian meteorological and hydrological service, 2023). the mineralogical and geochemical composition of the loess as parent material is consistent at both sites and has been described in detail in numerous publications (galović, 2014, 2016; galović & peh, 2016). dalj the bedrock of the daljska planina (dalj hill) consists of miocene conglomerates, limestones and sandstones covered by clayey and sandy sediments from the lower pliocene (velić et al., 1985). at the beginning of the quaternary, the subsidence rate increased, resulting in intense sedimentation. tectonic activity during the middle and upper pleistocene caused an uplift of the erdut hill, while the northern and southern slopes underwent relative subsidence (velić et al., 1985; trifunović, 1985; bačani et al., 1999). the dalj profiles (p-3: 45°26’14” n. lat., 18°58’10” e. long. and p-6 45°26’46” n. lat., 18°56’34” e. long.) are located about 5 km south-southwest of the center of dalj village (fig. 1b). profile p-3 is at an altitude of 88.7 and profile p-6 at an altitude of 88.3 m above sea level. zmajevac the bansko brdo is an asymmetric horst, tectonically elongated in a ne-sw direction and has a height of about 243 m a.s.l. tectonic activity led to synsedimentary effusion of basaltic andesite and deposition of volcanic breccias. the miocene age of the andesites is confirmed by k-ar dating (14.5±0.4 and 13.8±0.4 ma at two sites) (pamić & pikija, 1987). loess is exposed over the volcaniclastic material. recent tectonic uplift has formed a complex horst, the bansko brdo. these neotectonic movements are still active (hećimović, 1991). the studied profile is located about 2 km ne of the village of zmajevac (45°48’49” n. lat., 18°49’33” e. long.), at an altitude of 124 m above sea level. 1.2. pedological setting in croatia, chernozem occurs only in the extreme northeast (fig. 2a, b), where it developed on carbonate loess with a high content of primary carbonates under conditions of a continental climate and grassland vegetation. it is assumed that the chernozem in croatia was a relict soil formed when the continental climate was characterized by dry summers and colder winters compared to today’s climate. such conditions enabled the humification of organic matter and contributed to the formation of a deep and humus-rich a horizon (gračanin, 1951; nejgebauer, 1951; škorić, 1960). the time of the formation of the chernozem in central europe, i.e. its absolute age, cannot yet be determined with certainty. a majority of authors of publications consider the early holocene as the time of chernozem formation (roeschmann et al., 1982; scheffer & schachtschabel, 2002), i.e., they believe that the formation of the chernozem ended around 5.500 years bc. this is because during this period there were favourable climatic conditions for the formation of a deep mollic a horizon. the climate conditions during this period were characterised by warm and humid springs, which allowed the growth of large amounts of biomass, i.e., dry and hot summers and cold winters, during which more intensive mineralisation of organic matter was prevented/limited. although it occupies only a small g eologia c roatica galović l. et al.: evidence and mineralogical and physico-chemical properties of chernozem and chernozem-like soils in croatia 115 figure 1. a) location of the studied soil profiles in eastern croatia (europe relief map, maps-for-free.com last accessed on june 21, 2022); b) geological map of eastern croatia (croatian geological survey, 2009) with the positions of the soil profiles in zmajevac – p-10 and in dalj p-3 and p-6). file:///c:\poslovno\radni\radovi\ðurðevaèki peski\note\submitted\geologica carpathica\again\maps-for-free.com g eo lo gi a c ro at ic a geologia croatica 76/3116 area (0.9 %), chernozem is an extremely important soil in croatia. the composition of typical chernozem in croatia is a-ac-c. confirmation of the existence of chernozems in croatia is provided, for example, by work referring to the existence of chernozems in neighbouring serbia, which croatia borders (gajić et al., 2006; bokhorst, et al., 2009; vidojević et al., 2016; radaković et al., 2019). in the area where chernozem is distributed in croatia, there is soil similar to chernozem, characterized by the presence of a humus accumulative horizon < 40 cm deep, and formed under the same conditions as chernozem. according to the croatian soil classification, such soil cannot be classified as chernozem due to the above criteria, but is classified as rendzina on loess, the composition of which is mostly a-c, more rarely a-ac-c. since such soils can be classified as chernozems according to the world reference base for soil resources (iuss working group wrb, 2022), they are treated as chernozem-like soils in this document. the area of this soil is not known, but it is estimated that it is not large. 2. methods 2.1. pedological analyses for the study of chernozem, two soil profiles were dug south of the dalj settlement, and for the study of rendzina chernozemlike soils, one soil profile was excavated near the zmajevac settlement (figs. 1b, 2b). for the pedological and mineralogical analy ses, soil samples were taken in disturbed and undisturbed conditions according to the pedogenetic horizons. the pedological analyses were carried out in the laboratory of the department of soil science, faculty of agriculture at the university of zagreb. various types of soil analyses were carried out according to standard methods. soil samples were prepared according to hrn iso 11464 (2009); determination of soil particle size distribution (mechanical composition), i.e. fine earth, was carried out using sieving and sedimentation methods according to hrn iso 11277 (2011) with evaluation of texture classes according to fao (2006); the stability of structural microaggregates was determined according to the vageler method (jdpz, 1971; škorić, 1982); the determination of the volume density of dry soil was carried out according to hrn iso 11272 (2017); the determination of the density of solid particles was carried out according to hrn iso 11508 (2004); determination of water retention capaci ty of soil, total pore content in soil and air capacity of soil was performed according to the gračanin method (jdpz, 1971; škorić, 1982); ph determination (h2o 1m kcl) was performed according to hrn iso 10390 (2005); humus content was determined according to the tjurin method (jdpz, 1966); determination of carbonate content volumetric method was performed according to hrn iso 10693 (2004). the organic carbon content was calculated from the humus content using the van bemmelen conversion factor (humus content/1.724). the colour of the soil in the wet and dry state was determined according to the munsell soil color charts (2013) and the structure according to fao (2006). 2.2. mineralogical analysis 2.2.1. modal analysis to determine the qualitative and semi-quantitative mineral composition of heavy and light mineral associations, ten samples of pedgenetic horizons (four from the p-3 and four from the p-6 soil profiles in dalj and two from the p-10 profile in zmajevac) were examined. after disaggregation in an ultrasonic bath and sieving to the size fraction 0.09-0.125 mm, the calcite was dissolved. this fraction was selected for analysis because it contains all the virtual mineral species in a ratio representative of the bulk sample. the heavy mineral fraction (hmf) was separated with sodium polytungstate (spt) (ρ = 2.8 g cm-3). the slides of the heavy and light mineral fraction (lmf) were examined with the polarising microscope axiolab.a1 from carl zeiss. the qualitative and semiquantitative composition of a sample was determined after 300400 grains were identified and the percentage of each mineral was calculated. since the specific gravity of muscovite is between 2.76 and 3.00 g cm-3, it is predominantly a component of hmf, but some crystals remain in lmf. therefore, the number of muscovite crystals counted as a component of lmf was multiplied by the percentages of lmf and added to the percentages of muscovite in hmf. canada balsam was used as the embedding medium. the weathering index (w.i.) was used to examine the degree of alteration of the analysed soil horizons. the w.i. was defined figure 2. a) the area with a dominant presence of chernozem, with occasional occurrences of rendzina on the loess; b) locations of soil profiles p-3, p-6 and p-10. g eologia c roatica galović l. et al.: evidence and mineralogical and physico-chemical properties of chernozem and chernozem-like soils in croatia 117 by brewer (1976) and applied by faivre et al. (2019) and galović & peh (in press) as the ratio of the percentages of resistant and non-resistant minerals: w.i. = (zrn + tur + rt + ttn + st + grt) / (ep-zo + amp + px + ky). it is calculated to four decimal places on the basis of the percentage contents of the mine rals analysed. a higher w.i. indicates significant or repeated weathering of the analysed grains due to long exposure to a warm and humid geochemical environment (pedogenesis) and/or resedimentation. 2.2.2. x-ray diffraction method the mineral composition of the soil samples of the fractions < 2 mm and < 2µm was measured by x-ray powder diffraction (xrd) with a panalytical x’ pert pro diffractometer, equipped with a cu-tube, graphite monochromator and pixel detector. samples of the fraction <2 mm (bulk samples) were dried, crushed and homogenised in an agate mortar to the powder fraction. the fraction <2 µm was separated from the insoluble residue by centrifugation after dissolving the carbonates with a 1 m naoac solution buffered to ph 5 with hoac and removing the organic matter with h2o2. the time and number of revolutions were determined according to stocks law. xrd patterns of the clay fraction were obtained on oriented mounts after different treatments: (a) air drying, (b) ethylene glycol solvation of air dried samples, (c) k+ saturation with 4m kcl solution, (d) mg2+ saturation with 4m mgcl2 solution, (e) dmso solvation of k-saturated samples, (f) ethylene glycol solvation of k-saturated samples, (g) solvation of mg-saturated samples with ethylene glycol, (h) solvation of mg-saturated samples with glycerol, (i) heating to 400°c for 1h, (j) heating of the saturated samples to 350°c and (k) heating to 550°c for 1h. according to brown (1961), brindlay & brown (1980), moore & raynolds (1997), velde & meunier (2008) and haris & white (2008), these treatments are a very efficient means of identifying and distinguishing clay minerals. semiquantitative estimates of minerals detected in bulk samples were determined by rietveld refinement using panalytical highscore plus software linked to the iccd mineralogical database. semiquantitative estimates of clay minerals in the fraction <2µm were determined from the relative intensities of characteristic x-ray reflections using the method of johns et al. (1954), where the number of plus signs represents their relative abundance in the sample. the abbreviations for the mineral names are used according to whitney & evans (2010). 3. results 3.1. soil properties according to the croatian soil classification (husnjak, 2014), the physico-chemical and mineralogical properties of chernozem are presented on the basis of two soil profiles and those of rendzina on loess (chernozem-like soil) based on one soil profile. soil profile p-3 is characterised by the structure of the apa-ac-c profile, where the surface part of the a horizon is anthropogenic down to a depth of about 42 cm and represents the arable horizon. the depth of the a horizon is about 65 cm (fig. 3). table 1. mechanical composition of soil and stability of macroaggregates. profile number horizon depth (cm) content of mechanical particles (%) in na-pyrophosphate (mm) 1texture stability of microaggregates 2.0-0.2 0.2-0.063 0.063-0.02 0.02-0.002 <0.002 2ss assessment p-3 ap 0-42 0.2 3.1 37.9 31.7 27.1 prgi 62.0 fairly stable a 42-65 0.3 2.8 36.9 32.2 27.8 prgi 55.3 fairly stable ac 65-110 0.6 2.9 38.6 33.4 24.5 pri c 110-150 0.7 9.1 42.1 32.0 16.1 pri p-6 ap 0-40 0.2 2.4 35.8 34.3 27.3 prgi 56.9 fairly stable a 40-72 0.2 4.8 33.7 33.7 27.6 prgi 51.4 fairly stable ac 72-106 0.3 3.5 35.6 36.4 24.2 pri c 106-140 0.5 5.1 40.8 36.6 17.0 pri p-10 a 0-30 0.5 6.4 51.7 28.4 13.0 pri 64.1 fairly stable c 30-100 0.3 7.5 51.6 28.3 12.3 pri 28.9 slightly stable 1pri silty loam; prgi silty clay loam; 2ss stability index figure 3. landscape with the corresponding soil profile p-3. g eo lo gi a c ro at ic a geologia croatica 76/3118 the soil texture in the ap and a horizons is silty clay loam, i.e. at the boundary between silty clay and silty clay loam. deeper in the soil profile it is silty loam. the clay particle content determined in the c horizon -parent substrate (loess) is significantly lower than in the upper horizons, where the reduction is about 40% (table 1). the stability of the structural microaggregates is fairly stable in the arable soil as well as in the lower part of the a horizon. the soil structure in the ap and a horizons is granular and the colour is very dark grayish brown (table 2). as a result of the anthropogenic influence on the soil by trampling, porosity is lowest in the surface ap horizon and then increases with depth (table 3). the water capacity of the soil changes slightly with depth down to the c horizon, where it is the lowest. the air capacity of the soil is broadly similar in trend to porosity, being lowest in the ap horizon and highest in the c horizon the parent substrate. this soil is carbonate-rich throughout the depth of the profile, although the carbonate content in the ap horizon is significantly lower compared to the other horizons. the content in the ap horizon is only 8% of the total carbonate content in the parent substrate (table 4). in the zone between 50 and 100 cm, the existence of secondary carbonates in the form of caco3 concretions and pseudomycelia was observed. accordingly, the soil reaction is alkaline, with the soil ph being lowest in the ap horizon and increasing with depth. the organic carbon content is highest in the ap horizon, followed by horizons a and ac ( table 4). the soil profile p-6 is also characterized by the horizon sequence ap-a-ac-c, whereby the surface part of the a horizon is also anthropogenic to a depth of about 40 cm (fig. 4). the soil texture is very similar to that of soil profile p-3. the ap and a horizons are silty clay loam, i.e. at the boundary between silty clay and silty clay loam. in the deeper horizons, the texture is silty loam. it is also characteristic of this profile that the content of clay particles in the parent substrate of the c horizon is significantly lower than in the upper horizons, where it amounts to about 35% (table 1). the structural microaggregates are fairly stable in the arable ap horizon as well as in the remaining part of the a horizon. the soil structure in the ap and a horizons is table 2. structure and colour of the soil. profile number horizon depth (cm) structure colur in the wet state in the dry state p-3 ap 0-42 granular 10yr 3/2 10yr 5/2 a 42-65 granular 10yr 3/2 10yr 5/2 ac 65-110 granular to crumbly 10yr 4/2 10yr 6/3 c 110-150 undeveloped 10yr 6/3-10yr 8/3 10yr 7/3-10yr 8/4 p-6 ap 0-40 granular 7.5yr 3/1 10yr 4/2 a 40-72 granular 10yr 3/2 10yr 6/2 ac 72-106 granular to crumbly 2,5yr 4/3 10yr 6/2 c 106-140 undeveloped 10yr 8/4-7,5yr 5/3 10yr 8/3-7,5yr 6/4 p-10 a 0-30 granular 10yr 3/2 2.5y 5/2 c 30-100 undeveloped 10yr 6/3 2.5y 7/4 table 3. basic physical properties of soil. profile number depth (cm) 1𝜌b g/cm3 2𝜌s g/cm3 3p 4swc 5ac % vol p-3 0-42 1.44 2.62 45.0 36.6 8.4 42-65 1.32 2.68 50.9 39.8 11.1 65-110 1.25 2.69 53.6 42.2 11.4 110-150 1.19 2.65 55.2 37.7 17.5 p-6 0-40 1.27 2.66 52.3 38.6 13.7 40-72 1.21 2.68 54.9 41.7 13.3 72-106 1.23 2.73 55.0 40.9 14.1 106-140 1.22 2.72 55.2 40.1 15.1 p-10 0-30 1.25 2.65 53.1 38.0 15.1 30-100 1.21 2.70 55.2 43.4 11.8 𝜌b volume density; 2 𝜌s – soil particle density; 3p total porosity; 4swc soil water capacity; 5ac air capacity figure 4. landscape with the corresponding soil profile p-6. g eologia c roatica galović l. et al.: evidence and mineralogical and physico-chemical properties of chernozem and chernozem-like soils in croatia 119 granular, and the color is dark brown in the ap horizon and brown in the rest of the a horizon (table 2). the porosity of the soil barely increases with depth. as a result of anthropogenic compaction, it is lowest in the ap horizon and then increases slightly with depth (table 3). the water capaci ty of the soil also increases with depth down to the c horizon – the parent substrate, where it is slightly lower. the air capacity of the soil is lowest in the ap horizon and increases with depth, being significantly higher in the c horizon compared to the upper horizons. the soil is carbonate-rich throughout the depth of the profile, and the carbonate content in this profile is significantly lower in the ap horizon compared to the other horizons (table 4). compared to the carbonate content in the parent substrate in the ap horizon, it is only 11%. the soil acidity is correspondingly alkaline, with the soil ph being lowest in the ap horizon and increasing with depth. secondary carbonates were found in the zone from 50 to 100 cm in the form of pseudomycelia and caco3 concretions in this soil profile. the organic carbon content is highest in the ap horizon and decreases with depth (table 4). soil profile p-10 is characterized by the horizon profile a-c, with the depth of the a horizon being about 30 cm (soil is beneath natural vegetation). the soil texture is silty loam in both the a and c horizons. interestingly, there are no significant differences in the content of individual particles between the a and c horizons. the structural microaggregates are fairly stable in the a horizon, while in the c horizon the stability of the aggregates is low (table 1). the soil structure in the a horizon is granular and in the c horizon it is not pronounced, while the soil colour is very dark grayish brown in the a horizon and pale brown in the c horizon (table 2). soil porosity and soil water capacity increase with depth, while soil air capacity and soil volume density decrease with depth (table 3). the soil is carbonate-rich throughout the depth of the profile, with lower carbonate content in the a horizon than in the c horizon. accumulations of secondary carbonates in the form of pseudomycelia and nodules were found in the c horizon. in relation to the carbonate content of the parent substrate in the a horizon, it is about 68%. the soil acidity is correspondingly alkaline, with a slightly lower soil ph in the a horizon compared to the c horizon. the organic carbon content is significantly higher in the a horizon compared to its content in the parent substrate (table 4). 3.2. mineralogical characteristics 3.2.1. modal composition the lmf in almost all samples is > 95%, even if muscovite is reported as a heavy mineral (see section 2.2.1, table 6 and figs. 6 and 7). the dominant component in the light mineral fraction is quartz (74 83%), followed by feldspar (16 8%) and lithic fragments (12 5%). comparing the proportions of weathered and fresh quartz grains, fresh grains account for 66% of all quartz in profiles p-3 and p-6 compared to 33% for weathered grains, while they are equally represented in profile p-10. feldspars are almost exclusively represented by k-feldspars, mostly orthoclase, rarely microcline. fresh feldspar grains predominate in the uppermost horizons of profiles p-3 and p-6 (fig. 6a), while weathered feldspars predominate in all other horizons. the fresh grains are rich in elongated inclusions (fig. 6b). in the rare cases where this was possible, they were determined to be idiomorphic zircon inclusions. weathered feldspars are kaolinized and sometimes even sericitized and contain no inclusions (fig. 6b). plagioclase is represented by up to 1 % of na-rich, equally weathered and fresh grains with a characteristic polysynthetic twinning. lithic fragments are mostly represented by metamorphic rocks (undulose quartz, muscovite and chlorite (rarely biotite and feldspars)) and sporadically by quartzite or chert. the contribution of hmf ranges from 1.85 to 5.54% and increases with depth in each profile. an exception is the uppermost horizon ap in profile p-6. the highest proportion of hmf is found in profile p-10 (3.96–5.54%). among the hmf, transparent heavy minerals predominate (69–87%). opâque grains (5–12%) are rare in profile p-10 (5–8%) and are mainly represented by limonite. chlorite (6–18%) is well rounded and often represents table 4. basic chemical properties of the soil. profile number depth (cm) ph caco3 (%) humus (%) 1soc (%)h2o kcl p-3 0-42 8.31 7.40 2.12 2.51 1.46 42-65 8.41 7.77 19.52 1.81 1.05 65-110 8.51 7.83 25.88 1.01 0.59 110-150 8.60 7.99 26.31 0.18 0.10 p-6 0-40 8.23 7.44 2.97 2.86 1.66 40-72 8.41 7.75 18.67 1.74 1.01 72-106 8.34 7.88 26.13 1.07 0.62 106-140 8.65 7.92 26.46 0.22 0.13 p-10 0-30 7.91 7.56 15.60 2.12 1.23 30-100 8.38 7.94 20.40 0.38 0.22 1soil organic carbon figure 5. soil profile p-10. g eo lo gi a c ro at ic a geologia croatica 76/3120 figure 6. photomicrographs of minerals from lmf and hmf of samples of the investigated profiles in polarized light: a) fresh k-feldspar rich in elongated inclusions – p3 65-110; b) weathered k-feldspar – p3 65-110; c) well-rounded fresh biotite (upper left) and chloritized biotite (lower right) – zn a; d) well-rounded fresh chlorite; e) well-rounded muscovite – p3 110-150; f ) muscovite with ragged rims containing elongated minerals with parallel extinction – zn c. table 5. modal composition of the light mineral fraction (values in %) and weathering index (legend in table 6). profile depth from the surface (cm) quartz feldspar lithic particles 1w.i.k-feldspar plagioclase fresh weathered fresh weathered fresh weathered quartzite chert other p-3 0-42 52 22 10 5 + 0 2 4 4 0.63 42-65 46 26 6 9 + 0 1 2 9 0.71 65-110 55 23 4 7 + 1 1 1 9 0.93 110-150 62 21 5 7 0 0 2 1 2 1.00 p-6 0-40 52 28 7 6 1 0 2 1 3 0.66 40-72 53 27 5 7 0 1 2 1 4 0.63 72-106 51 26 6 9 0 0 2 2 3 0.80 106-140 55 28 4 5 1 + 1 1 6 0.69 p-10 0-30 43 41 3 5 1 0 1 1 6 0.50 30-100 39 37 4 9 0 1 0 1 9 0.70 1w.i. – weathering index g eologia c roatica galović l. et al.: evidence and mineralogical and physico-chemical properties of chernozem and chernozem-like soils in croatia 121 chloritised biotite (fig. 6c & d). chlorite is most abundant in the p-10 profile (14–18%), which is also richest in biotite (3–7%). biotite is present in all samples. muscovite is present in all samples, but its content varies considerably (8–65%). it is mostly represented by flakes and rarely by sericite. the muscovite flakes in profiles p-3 and p-6 are wellrounded (fig. 6e), while the flakes from profile p-10 have ragged rims and contain many needle-like minerals with parallel extinction (fig. 6f). like other sheet minerals (biotite and chlorite), muscovite is most abundant in profile p-10 (41–65%). primary chlorite crystals can be confirmed by the presence of primary chlorite in lithic fragments (metamorphic rocks). however, in many coloured leaflets, it was difficult to determine if it was still biotite or if it could be considered chlorite (chloritised biotite). the most abundant transparent heavy minerals are resistant garnet grains (12–34%), followed by amphiboles (12–27%), the epidote-zoisite group (5–17%) and pyroxenes (3–16%). garnet grains are often pink, sometimes colourless. amphiboles are mostly represented by weathered dark green to olive green hornblende, sometimes by fresh brown to light olive brown amphiboles and sporadically by bluish purple glaucophane. green hornblende grains are often chloritised. the ap horizon of the p-3 profile is enriched in amphiboles. the epidote-zoisite group is represented by equal-sized, irregular, weathered grains. epidote is generally yellow to greenish-yellow and shows weak pleochroism, while zoisite is colourless and shows a characteristic anomalous blue interference colour. the pyroxene group is dominated by clinopyroxene. accompanying minerals are kyanite, staurolite, tourmatable 6. modal composition of heavy and light mineral association. profile depth from the surface (cm) composition of lmf 100% hmf w % composition of hmf 100% transparent heavy minerals 100% qz fsp l op chl bt thm ms ep-zo amp px grt ky st tur zrn rt ttn chr ap p-3 0-42 74 16 10 1.85 8 11 0 81 18 14 27 8 26 1 2 + + 2 1 0 + 42-65 72 16 12 2.65 11 10 1 79 28 17 16 8 19 0 3 1 3 3 1 0 2 65-110 77 12 10 3.28 11 7 1 81 19 14 12 15 26 1 2 1 2 6 2 0 1 110-150 83 12 5 4.85 5 8 1 87 11 14 18 12 34 0 2 2 2 2 2 0 0 p-6 0-40 80 14 6 2.45 9 6 1 85 8 17 22 16 26 1 3 2 1 3 1 + 0 40-72 80 13 7 1.91 8 12 1 79 17 12 25 12 24 2 2 3 0 1 2 0 1 72-106 77 16 7 2.30 10 11 1 78 19 14 18 11 30 1 2 + 1 1 1 0 1 106-140 82 10 8 2.64 12 15 0 73 15 15 24 11 25 + 2 2 1 3 1 0 + p-10 0-30 83 8 9 2.65 8 14 3 75 41 16 16 7 18 + 1 0 1 + + 0 + 30-100 76 14 10 3.28 5 18 7 69 65 5 12 3 12 0 1 1 0 0 0 0 0 legend: lmf = light mineral fraction, hmf = heavy mineral fraction, thm = transparent heavy minerals, qz = quartz, fsp = feldspar, l = transparent lithic particles, op = opâque minerals, chl = chlorite, bt = biotite, ms = muscovite, ep-zo = epidote–zoisite, amp = amphibole, px = pyroxene, grt = garnet, ky = kyanite, st = staurolite, tur = tourmaline, zrn = zircon, rt = rutile, ttn = titanite, chr = chromite, ap = apatite, + = minerals with occurrence < 0.5% (symbology according to warr (2021)). figure 7. modal composition of lmf (values in %). legend in figure 8. g eo lo gi a c ro at ic a geologia croatica 76/3122 line, zircon, rutile and titanite. the results of the modal analyses are presented in tables 5 and 6 and in figs. 6, 7 and 8. the uppermost ap horizons of dalj profiles p-3 and p-6 are characterised by sporadic spherical grains of devitrified volcanic glass in the lmf (fig. 7) and weathered carbonate grains in the hmf (fig. 8), in addition to a higher content of fresh quartz and feldspar grains. since the specific gravity of calcite is 2.71 g cm–3, dolomite is 2.85 ± 0.01 g cm-3 and the applied heavy liquid is 2.8 g cm–3, they are determined as dolomite grains. the most important morphological feature of the analysed grains is that they are highly spherical, rounded, hypidiomorphic to allotriomorphic grains. this is most noticeable in the rounded habit of typical (hyp-)idiomorphic crystals such as tourmaline and zircon (fig. 8). the distribution of w.i. along the investigated soil profiles (table 5; fig. 9) shows a clear increase in w.i. along profiles p-3 and p-10 and an increasing trend along profile p-6. 3.2.2. semiquantitative x-ray diffraction analysis the investigated xrd patterns of randomly oriented powder samples from profiles p-3 and p-6 show that quartz, micaceous minerals (muscovite/illite) and carbonates (caco3) predominate (table 7). their content is largely uniform across the profile, with the exception of carbonates, which decrease sharply in the ap horizon, while their content increases deeper in the profile. plagioclase, potassium feldspar, dolomite and chlorite are present in lower amounts. negligible contents of amphiboles are present in all samples. unlike the profile of dalj, samples from profile p-10 contain large amounts of quartz, carbonate minerals, micaceous minerals, and plagioclase. potassium feldspars, amphiboles and other phyllosilicates are present in lower amounts. compared with the profiles in dalj this horizon contains a slightly larger amount of dolomite and amphiboles. figure 8. modal composition of hmf (values in %). legend: lmf = light mineral fraction, hmf = heavy mineral fraction, thm = transparent heavy minerals, qz = quartz, fsp = feldspar, l = transparent lithic particles, op = opâque minerals, chl = chlorite, bt = biotite, ms = muscovite, ep-zo = epidote–zoisite, amp = amphibole, px = pyroxene, grt = garnet, ky = kyanite, st = staurolite, tur = tourmaline, zrn = zircon, rt = rutile, ttn = titanite, chr = chromite, ap = apatite, + = minerals with occurrence < 0.5% (symbology according to warr (2021)). figure 9. distribution of w.i. (w.i. = (zrn + tur + rt + ttn + st + grt) / (ep-zo + amp + px + ky) in investigated soil profiles. (legend in table 6). g eologia c roatica galović l. et al.: evidence and mineralogical and physico-chemical properties of chernozem and chernozem-like soils in croatia 123 analysis of the fraction < 2µm determined that the most abundant clay minerals in all profiles are illite and chlorite. their basal reflections at about 14 å for chlorite and at 10 å for illite are clearly visible after each treatment. their content is constant over the entire length of the profiles. except in the clay fraction, the clearly visible peak at 4.7 å of bulk samples indicates the prese nce of chlorite in the silt fraction. in addition, the presence of expandable vermiculite was noted in all horizons, except in horizon c from profile p-10 were smectite is present. the content of vermiculite increases with depth, so it is most abundant in the table 7. semiquantitative mineral composition of the fractions < 2 mm and < 2 µm. profile mineral composition of fraction < 2 mm clay minerals in fraction < 2 µm qtz cal dol plg k-fs amp ms/il phyl + gt* chl il vr sm lcv/ hcs klnd mlm gt p-3 ap 32 3 4 9 22 1 22 6 ++ +++ + + + a 28 18 4 18 7 ~ 21 4 ++ +++ + + + ac 26 25 7 12 5 ~ 20 5 ++ +++ ++ + + c 26 26 8 13 8 ~ 14 5 ++ +++ ++ + + + p-6 ap 40 2 4 14 10 1 22 7 ++ +++ + + + a 26 19 7 12 8 1 24 2 ++ +++ + + ac 27 26 8 11 3 1 21 3 ++ +++ ++ + c 27 26 10 12 3 ~ 20 2 ++ +++ ++ + + + p-10 a 30 12 15 12 11 2 12 6 ++ +++ ~ + ~ c 29 18 11 14 6 2 13 6 ++ +++ + + ~ legend: qtz-quartz, cal-calcite, dol-dolomite, k-fs-potassium feldspar, plg-plagioclase, amp-amphibole, ms/il-muscovite or illite (micaceous minerals), il – illite, chl-chlorite, vr-vermiculite, sm-smectite, gt-goethite, phyl – phyllosilicates, klnd – well crystallized kaolinite (which reacted with dmso), mlmmixed layer minerals which could be chlorite–vermiculite ore chlorite–smectite, lcv/hcv – low charge vermiculite/high charge smectite, ~ in trace, + relative abundance of clay minerals within horizons based on x-ray diffraction (no quantitative value is assigned to +), * based on the analysis of fraction < 2 µm. figure 10. x-ray diffraction patterns of the clay fraction (< 2µm) from p-3 profile – horizon ac. ad – air dried, eg – ethylene glycol solvation, mg – saturated with mg2+, ksaturated with k+, glc – solvated with glycerole, dmso – solvated with dimethyl sulfoxide, 400 – heated to 400°c, 550 – heated to 550°c. (legend in table 7). g eo lo gi a c ro at ic a geologia croatica 76/3124 horizons ac and c in profiles p-3 and p-6. evidence for the presence of expandable vermiculite is the shift of the 14 å reflections to the 17 å position after glycolisation of air-dried and mg-saturated samples, but the same is not observed in k-saturated samples (moore & raynolds, 1997). furthermore, there is a clear sign of the presence of goethite in horizons from profiles p-3 and p-6, but only in the clay fraction. in profile p-10 the presence of goethite is in trace amounts. its diffraction reflection is visible at 4.17 å in all samples but disappeared after heating above 350°c (brindlay & brown, 1980; moore & raynolds, 1997). a minor amount of well-crystallised kaolinite (kaolinite that has reacted with dmso) is found in all samples from the p-3 profile and in the a horizon of the p-6 profile (fig. 10). the reflex at 7 å of the samples saturated with dmso may indicate pedogenetically formed kaolinite but also the chlorite and vermiculite. however, the clear and sharp peak instead of the small and very broad peak indicates that there is probably no or a very low presence of poorly crystallized kaolinite. there are also some differences between the two analyzed soil profiles. in horizon c of the profile p-3, the presence of low charge vermiculite (lcv) or high charge smectite (hcv) was detected. namely, after treatment of the mg-saturated samples with glycerol, the 14 å reflections were found to expand to 17–18 å, but this effect was not visible in the reflections after ethylene glycol solvation of the k-saturated samples. it means that a clay mineral is present in the samples that has a characteristic of both vermiculite and smectite (moore & raynolds, 1997; terhorst et al., 2012, durn et al., 1999). however, in a sample from horizon c in p-6 profile, the presence of mixed-layer clay minerals was detected on the basis of the occurrence of reflections at 12-13 å after heating to 550°c, and it is most likely that this is some kind of interstratification between chlorite and vermiculite (fig. 11; brindley & brown, 1980; moore & raynolds, 1997). 4. discussion according to the criteria of the croatian soil classification (husnjak, 2014), the systematic unit for profiles p-3 and p-6 can be defined as chernozem on loess, carbonate, medium deep, unglazed, and anthropogenic. according to the criteria of the world reference base for soil resources (iuss working group wrb, 2022) and based on the identified soil properties, the presence of a chernic horizon and a calcic horizon was determined in both profiles, based on which the pedosystematic unit can be defined as hortic calcic chernozem (epiloamic, endosiltic, aric, humic). the systematic unit for profile p-10 can be defined as rendzina on loess, carbonate, medium deep, according to the above-mentioned soil classification of croatia. as chernic and figure 11. x-ray diffraction patterns of the clay fraction (< 2µm) from p-6 profile – horizon c. ad – air dried, eg – ethylene glycol solvation, mg – saturated with mg2+, ksaturated with k+, glc – solvated with glycerole, dmso – solvated with dimethyl sulfoxide, 400 – heated to 400°c, 550 – heated to 550°c. (legend in table 7). g eologia c roatica galović l. et al.: evidence and mineralogical and physico-chemical properties of chernozem and chernozem-like soils in croatia 125 calcic horizons were also detected in this profile, the pedosystematic unit can be defined as calcic chernozem (siltic) according to the wrb. research findings indicate a change or degradation of chernozem. although it was established as early as 1960 that the chernozem in croatia is gradually degrading, i.e. turning brown, due to higher temperatures and greater precipitation compared to the period of its formation (škorić, 1960), part of the chernozem is still carbonised. the research results indicate that the signs of degradation in the chernozem are mainly in the form of reduced carbonate content in the surface zone, which is result of centuries of continuous movement of carbonates from the surface zone to the subsurface zone. it is assumed that the chernozem had > 4% humus in the a horizon at the time of its complete formation. however, due to climate change and human influence, especially during the last century, the humus content has decreased drastically. the significant influence of human activities is highlighted by dokuchaev (1948), who believes that the rapid and intensive cultivation of chernozem began as early as the 17th century. the degradation of chernozem in croatia is noted by škorić (1960), who found a humus content of only 2-3.5%, and nejgebauer (1951), who found 2-4% humus in chernozem in the northern part of neighbouring serbia (vojvodina). other authors also confirm the degradation of chernozem, for example krupenykov (2008); łabaz et al. (2019), and kravichenko et al. (2012). the significantly higher content of clay particles in the ap, a, and ac horizons in both chernozem soil profiles compared to the content of clay particles in the c horizon, parent substrate, indicates the current processes of transformation of mineral matter with the formation of secondary clay minerals. at the same time, as already mentioned, the significantly lower content of carbonates in the ap horizon compared to the other horizons and especially compared to the parent substrate indicates the current processes of carbonates displacement (leaching, migration). this means that carbonates are leached from the surface into the deeper horizons due to the processes of desilication and acidification of the soil. these processes can be a consequence of heavy rainfall, but also of agricultural activities, as is the case with the soils of profiles p-3 and p-6. the content of organic carbon indicates the presence of long-term processes of mineralization of organic matter in the soil in connection with the processes of humification, which also confirms the gradual degradation of the soil from the aspect of this property. based on the previously published analysis of the modal composition of loess as the parent material of the investigated recent soil profiles in the area investigated in this paper (galović, 2016) and on the basis of the discriminant function analysis of the obtained mineral composition (galović & peh, 2016), it can be concluded that the parent material of the studied recent soils has a similar mineral composition. the authors note that the modal composition in the areas covered by this work points to the danube floodplain region (thamó-bozsó & kovács, 2007) and redeposited loess from hungary (thamó-bozsó et al., 2014; újvári et al., 2008, 2014, 2016) as the main source of the material. as the danube originates from the same region as the sava and drava rivers (the alpine region), its mineral composition is similar. however, as galović (2016) noted, the analysis of the modal composition of the loess horizons showed significant differences in the proportion of phyllosilicates (muscovite, biotite and chlorite), indicating the different area of origin and provenance of the source material. the source material for profile p-10 (rich in muscovite and other phyllosilicates) could be regional tertiary sediments. these sediments are partly derived from the paleozoic muscovite-rich rocks (e.g. garnet-muscovite gneisses, biotite gneisses and muscovite-biotite gneisses, mica schists, pegmatites and aplites) of the slavonian mountains (kovačić et al., 2011; slovenec et al., 2020; šegvić et al., 2022). higher amounts of chemically stable muscovite indicate the possibility of multiple cycles of repeated resedimentation (frechen et al., 2003; galović, 2014, 2016). these conclusions are also supfigure 12. modal composition of hmf without muscovite (values in %). legend in figure 8. g eo lo gi a c ro at ic a geologia croatica 76/3126 ported by the frequent presence of regeneration rims on the weathered quartz grains in all investigated profiles. klepikov et al. (2022) described the mechanism of tangential growth from existing surfaces and concluded that regeneration growth is very rapid due, to the absence of the limiting nucleation stage of a new atomic layer (kempe, 2012). thus, alpine and local source areas are the sources of the aeolian sediments in the pannonian basin. however, the proportion and habitus of muscovite and other phyllosilicates indicate different local origins. namely, soil profiles p-3 and p-6 contain well-rounded, smooth muscovite flakes, whereas the flakes from profile p-10 have fissured margins and contain a lot of needle-like inclusions. galović (2016) described in detail possible causes and sources for the enrichment of muscovite (and other flaky minerals). she claimed that the flat shape significantly favours aeolian transport. namely, there is a possibility that the wind force that caused the accumulation of muscovite in the sediments was too weak to transport large quantities of uniformly sized and elongated grains. modal compositions of loess in croatia are presented in many publications (mutić, 1990; durn, 2003; durn et al., 2007; rubinić et al., 2015, 2018; wacha et al., 2013). they indicate a homogeneous and uniform composition of the loess dominated by quartz and containing muscovite as a component of lmf. since the muscovite-rich layers have a homogeneous composition along the p-10 profile, it can be concluded that there was no enrichment after the deposition of eolian sediments. the muscoviterich material was homogenised before or during aeolian transport and then deposited in zmajevac as homogeneous sediment before the onset of pedogenetic processes. fractionation by wind energy in semi-arid mid-latitude regions during the late pleistocene could be influenced by both the aerodynamic properties of the particles (surface, shape) and density (újvári et al., 2016). muscovite is resistant to chemical weathering and inert during pedogenesis. however, the unusual enrichment of muscovite led to a depletion of all other components of the transparent minerals of the hmf. in a “compositional dataset”, changes in the content of one variable in a sample are accompanied by changes in the contents of other variables in the same sample (aitchison, 1986, 1997; galović, 2016; galović & peh, 2016, in press). therefore, to enable a comparison of the composition of the transparent heavy minerals in the investigated profiles, an additional diagram was created that excludes the proportion of muscovite (fig. 12). figure 12 shows the enrichment of chemically (pedogenetically) not resistant amphibole in the uppermost horizon of profile p-3. galović (2016) claims that abrasion dominates over chemical weathering because less weathering-resistant minerals (e.g. amphibole) are present in all studied horizons. however, in this research, the intense weathering of unstable mineral grains is confirmed by the chloritisation of amphibole and biotite. although the presence of primary chlorite crystals can be proven by the occurrence of primary chlorite in lithic fragments originating from the mica schists, it was difficult to distinguish whether some particles were primary biotite or chloritised biotite. the decision was based on the degree of chloritisation of the biotite. detailed modal analyses of the lmf indicate that there are twice as many fresh quartz grains as weathered ones in soil profiles p-3 and p-6, while they are equally represented in profile p-10. furthermore, weathered feldspar grains predominate in the uppermost horizons of profiles p-3 and p-6, especially in the uppermost horizon of profile p-3. there are twice as many fresh grains compared to weathered grains. in the p-10 profile, fresh and weathered grains are equally represented. the higher proportion of fresh grains in the surface horizons can also be confirmed by the modal composition of the hmf. the w.i. (ratio of chemically resistant and non-resistant transparent heavy minerals) shows an increasing trend with depth of the investigated profiles (table 5; fig. 9). a higher w.i. indicates significant or repeated weathering of the analyzed grains due to long exposure to a warm and humid geochemical environment and/or redeposition (faivre et al., 2019). the analyzed soils are poorly developed compared to very well-developed mediterranean soils, with a w.i. between 5.11 and 11.48% (faivre et al., 2019). the dominance of unstable minerals (epidote-zoisite group, amphibole, pyroxene and kyanite) in the surface horizons and the tendency for their proportion to decrease with depth indicate a continuous eolian enrichment of the soil with fresh, unweathered material. the new eolian contribution was introduced into the soil profiles naturally (profile p-10) and/or by human action (profiles p-3 and p-6). the evidence for synpedological aeolian sedimentation is the higher content of fresh quartz and feldspar grains, sporadic spherical grains of devitrified volcanic glass and weathered dolomite grains in the ap horizons of profiles p-3 and p-6. the eolian contribution in recent soil profiles is described in galović & peh (2014). faivre et al. (2019) assumed that the milna drainage basin have a polygenetic origin, similar to terra rossa along the eastern adriatic coast (durn et al., 2007; romić et al., 2014). furthermore, a recent investigation of loess sections in the south-eastern and central carpathian basin (marković et al., 2023) indicates that favourable local vegetation conditions for dust uptake existed throughout the late pleistocene. these environmental conditions promote higher availability of source material for further aeolian activities. the present records provide new insights into dust accumulation regimes over the eastern side of the bačka loess plateau. they represent an important step towards the establishment of a chain line from the thin loess-like sediments of the banat foothills in the east to the thicker and apparently more complete loess sections of the southeastern and central carpathian basin. in addition to the modal analysis, the composition of the clay fraction also suggests that the parent material of investigated soil profiles is underlying loess-paleosol sequences, the mineralogical composition of which is also consistent with some previous works (galović, 2016; grizelj et al., 2016; urumović et al., 2017). according to them, the mineralogical composition of the underlying loess-paleosol sequence consists of quartz, micaceous minerals (illite and muscovite), chlorites and expandable clay minerals, while to a lesser extent it contains kaolinite, carbonates and feldspars. a very similar composition was obtained by analysis of the soil samples from profiles p-3 and p-6. quartz, micaceous minerals and calcite predominate in bulk composition, which is also the case in the parent material. in the fraction < 2 µm of soil profiles p-3 and p-6, the dominant clay minerals are illite and chlorite, whose content is constant in all horizons. they most likely originate from the parent material, especially the chlorite grains present in the silt fraction. modal analysis revealed that a small proportion of chlorite was formed by the chloritisation of biotite and amphiboles. similar to chlorite, vermiculite can also be formed by the decomposition of biotite or by the decomposition of chlorite during pedogenesis (velde & meunier, 2008). this is indicated by the presence of chlorite mixed layer clay minerals in the c horizons of profile p-6. slightly lower amounts of vermiculite in the upper part of both profiles could indicate the displacement of the clay fraction by water infiltration g eologia c roatica galović l. et al.: evidence and mineralogical and physico-chemical properties of chernozem and chernozem-like soils in croatia 127 and wind erosion (altay, 1997) or the transformation of a vermiculite clay mineral to kaolinite. in well developed soils, the end product of weathering of soil minerals is kaolinite or smectite together with iron oxides and hydroxides. in analyzed soils, the presence of well crystallized kaolinite is clearly detectable and most likely inherited. there is no clear evidence of the presence of poorly crystallized kaolinite in the samples. although modal analysis revealed the presence of feldspar grains with weathered rime that could consist of poorly crystallized kaolinite the 7 å kaolinite peak is not present in the x-ray diffraction analysis. the reason for this may be the small amount of poorly crystallized kaolinite, but also the presence of chlorite and vermiculite, whose reflection at the same diffraction position masks the reflection of kaolinite. the presence of kaolini te, even in very small quantities, as well as goethite, may indicate an influence of chemical weathering on the degradation of chernozem profiles. in this case, it cannot be claimed with certainty that the feldspars have been weathered recently, primarily due to the basic environment with a ph of > 8 (table 4). 5. conclusions the research results confirm the existence of chernozem in croatia, both according to the soil classification of croatia and the world reference base for soil resources. considering the area occupied by the chernozem soil type according to the croatian soil classification, which is about 50,000 ha, it cannot be claimed on the basis of these studies that the entire chernozem area belongs to the reference group of chernozem soils according to the word reference base for soil resources. based on soil characteristics, changes indicating soil degradation have been identified, in particular the reduction of organic matter and the displacement of carbonates from the surface to deeper zones. the presence of a chernozem degradation process due to the impact of recent weathering processes can only be indicated by the presence of goethite in the fraction < 2 µm. kaolinite and weathered feldspar grains are not products of recent weathering, primarily due to the alkaline environment, but are most likely inherited. although the parent material of the studied recent soils has a similar mineral composition, differences in the proportion of phyllosilicates (muscovite, biotite and chlorite) and their habitus indicate the different area of origin and provenance of the source material. furthermore, the dominance of unstable minerals (epidote-zoisite group, amphibole, pyroxene and kyanite) in the surface horizons and the tendency for their proportion to decrease with depth indicate a continuous eolian enrichment of the soil with fresh, unweathered material. the synpedological eolian sedi mentation is confirmed by the higher content of fresh quartz and feldspar grains, sporadic spherical grains of devitrified volcanic glass and weathered dolomite grains in the ap horizons of profiles p-3 and p-6. following the principle of actualism, it is therefore important to be aware, during investigations of paleosols, even buried ones, that synpaleopedological aeolian sedimentation could occur and lower a certain degree of pedogenesis. acknowledgment this work has been fully supported by the croatian science foundation under the project accent [3274]. the authors thank nina hećej for her cooperation. we are grateful to the reviewers petar stejić and domagoj rastija and associated editor goran durn for their thorough reviews, which greatly improved the manuscript. references aitchison, j. (1986): the statistical analysis of compositional data.– chapman and hall, london, new york, 416 p. doi: 10.1007/978-94-009-4109-0 aitchison, j. (1997): the one-hour corse in compositional data analysis or compositional data analysis.– iamg97, 33 p. altay, i. (1997): red mediterranean soils in some karstic regions of taurus mountains, turkey.– catena, 247–260. doi: 10.1016/s0341-8162(96)00041-0 altermann, m., rinklebe, j., merbach, i., körschens, m., langer, u. & hofmann, b. (2005): chernozem – soil of the year 2005.– j. plant nutr. soil sc., 168/6, 725-740. doi: 10.1002/jpln.200521814 bačani, a., šparica, m. & velić, j. (1999): quaternary deposits as the hydrogeological system of eastern slavonia.– geol. croat., 52/2, 141–152. bašić, f. (2013): soils of croatia.– the world soils book series. springer/series 8915, 179 p. doi: 10.1007/978-94-007-5815-5 bogunović, m., vidaček, ž., husnjak, s. & sraka, m. (1988): inventory of soil in croatia.– agriculturae conspectus scientificus, 63/3, 105–112. bogunović, m., vidaček, ž., racz, z., husnjak, s., špoljar, a. & sraka, m. (1998): fao unesco pedološka karta 1:1.000.000 [fao unesco pedologycal map 1:1.000.000 – in croatian].– agronomski fakultet sveuč. u zagrebu, zavod za pedologiju, zagreb. bokhorst, m.p., beets, c.j., marković, s.b., gerasimenko, n.p., matviishina, z.n. & frechen, m. (2009): pedo-chemical climate proxies in late pleistocene serbian–ukranian loess sequences.– quatern. int., 198/1–2, 113–123. doi: 10.1016/j.quaint.2008.09.003 brewer, r. (1976): fabric and mineral analysis of soils.– krieger, huntington, new york, 482 p. brindley, g.w. & brown, g. (1980): crystal structures of clay minerals and their x-ray identification.– miner. soc., london, 495 p. doi: 10.1180/mono-5 bronger, a. (2003): corelation of loess-paleosol sequences in east and central asia with se central europe: towards a continental queternary pedostratigraphy and paleoclimatic history.– quat. int., 106/107, 11–31. brown, g. (1961): the x-ray identification and crystal structures of clay minerals.– miner. soc, london, 544 p. cgs-department of geology (2009): geological map of republic of croatia, m 1:300.000.– croatian geological survey, department of geology, zagreb. ćirić, m. (1965): atlas šumskih zemljišta jugoslavije. jugoslavenski poljoprivredno šumarski centar beograd. grafički zavod hrvatske, zagreb, 250 p. croatian meteorological and hydrological service (2023): wind atlas, https://meteo.hr/klima.php?section=klima_hrvatska&param=k1_8 (last accessed 1st march, 2023). dokuchaev, v.v. (1948): russian chernozem: selected works [in russian].– sel´ khozgiz, moscow, 1, 21–476. durn, g., ottner, f. & slovenec, d. (1999): clay minerals as an indicator of the polygenetic nature of terra rossa in istria, croatia.– geoderma, 91, 1–2, 125–150. durn, g. (2003): terra rossa in the mediterranean region: parent materials, composition and origin.– geol. croat., 56/1, 83–100. doi: 10.4154/gc.2003.06 durn, g., aljinović, d., crnjaković, m. & lugović, b. (2007): heavy and light mineral fractions indicate polygenesis of extensive terra rossa soils in istria, croatia.– in: mange, m.a. & wright, d.t. (eds.): heavy minerals in use. dev. sedim., 58, 701–737. doi: 10.1016/s0070-4571(07)58028-3 eckmeier, e., gerlach, r., gehrt, e. & schmidt, m.w.i. (2007): pedogenesis of chernozems in central europe – a review.– geoderma, 139, 288–299. doi: 10.1016/j.geoderma.2007.01.009 faivre, s., galović, l., sümegi, p., cvitanović, m., náfrádi., k. & horvatinčić, n. (2019): palaeoenvironmental reconstruction of the milna valley on the island of vis (central adriatic) during the late holocene.– quatern. int., 510, 1–17. doi: 10.1016/j.quaint.2018.11.017 fao (2006): guidelines for soil description. 4th ed.– fao, rome, 97 p. frechen, m., oches, e.a. & kohfeld, k.e. (2003): loess in europe – mass accumulation rates during the last glacial period.– in: derbyshire, e. (ed.): loess and the dust indicators and records of terrestrial and marine palaeoenvironments (dirtmap) database.– quat. sci. rev., 22/18–19, 1835–1857. doi: 10.1016/s0277-3791(03)00183-5 frechen, m. & pécsi, m. (2004): abony brickyard: irsl and tl analysis of “infusion loess”.– loessinform, 4, 63–70. gajić, b., živković, m. & dugalić, g. (2006): aggregate composition of carbonate chernozem from south banat.– zemljište i biljka, 55/ 2, 131–140. galović, l. (2014): geochemical archive in the three loess/paleosol sections in the eastern croatia: zmajevac i, zmajevac and erdut.– aeolian res., 15, 113–132. doi: 10.1016/j.aeolia.2014.07.004 galović, l. (2016): sedimentological and mineralogical characteristics of the pleistocene loess/paleosol sections in the eastern croatia.– aeolian res., 20, 7–23. doi: 10.1016/j.aeolia.2015.10.007 g eo lo gi a c ro at ic a geologia croatica 76/3128 galović, l., frechen, m., halamić, j., durn, g. & romić, m. (2009): loess chronostratigraphy in eastern croatia – a first lu minescence dating approach.– quatern. int., 198, 85–97. doi: 10.1016/j.quaint.2008.02.004 galović, l. & peh, z. (2016): mineralogical discrimination of the pleistocene loess/ paleosol sections in srijem and baranja, croatia.– aeolian res., 21, 151–162. doi: 10.1016/j.aeolia.2016.04.006 gorjanović-kramberger, d. (1911): iz prapornih predjela slavonije [from the loess areas of slavonia – in croatian and german].– vijesti geol. povjerenstva, 2, 28–30, zagreb. gorjanović-kramberger, d. (1922): morfologijske i hidrografijske prilike prapornih predjela u srijemu te pograničnih česti županije virovitičke [morphological and hydrographic conditions of flag areas in srijem and the border areas of virovitica county – in croatian].– glasnik hrv. prir. društva, 34/2, 111–164, zagreb. gračanin, m. (1951): pedologija, iii. dio sistematika tala [pedology, part iii. systematics of soils – in croatian].– školska knjiga, zagreb, 298 p. hećimović, i. (1991): osnovna geološka karta sfrj 1:100.000. tumač za list mohač, geomorfološka analiza [basic geological map of sfry 1:100.000, geology of the mohač sheet, geomorphological analysis – in croatian].– fond struč. dok. hgi zagreb, 5 p. hrn iso 10390 (2005): soil quality – determination of ph (iso 10390:2005).– croatian standard institute, zagreb. hrn iso 10693 (2004): soil quality – determination of carbonate content – volumetric method (iso 10693:1995).– croatian standard institute, zagreb. hrn iso 11272 (2004): soil quality– determination of dry bulk density (iso 11272:1998).– croatian standard institute, zagreb. hrn iso 11277 (2011): soil quality – determination of particle size distribution in mineral soil material – method by sieving and sedimentation (iso 11277:2009).– croatian standard institute, zagreb. hrn iso 11464 (2009): soil quality – pretreatment of samples for physico-chemical analysis (iso 11464:2006).– croatian standard institute, zagreb. hrn iso 11508 (2004): soil quality – soil quality – determination of particle density (iso 11508:1998).– croatian standard institute, zagreb. husnjak, s. (2014): sistematika tla hrvatske [soil systematics of croatia – in croatian].– hrvatska sveučilišna naklada, zagreb, 375 p. iuss working group wrb (2022): world reference base for soil resources. international soil classification system for naming soils and creating legenda for soil maps. 4th edition.– international union of soil sciences (iuss), vienna, austria, 234 p. jdpz (1966): priručnik za ispitivanje zemljišta, knjiga 1, hemijske metode ispitivanja zemljišta [manual for soil testing, book 1, chemical methods of soil testing – in serbian].– jugoslovensko društvo za proučavanje zemljišta (jdpz), 270 p. jdpz (1971): priručnik za ispitivanje zemljišta, knjiga 5, metode istraživanje fizičkih svojstava zemljišta [manual for soil testing, book 5, methods of investigation of physical properties of soil – in serbian].– jugoslovensko društvo za proučavanje zemljišta (jdpz), 205 p. jelić, t. & kalogjera, a. (2002): tematski zemljovidi [thematic maps – in croatian].– in: borovac, i. (ed.): veliki atlas hrvatske [the big atlas of croatia – in croatian]. mozaik knjiga, zagreb, 338–355. jenny, h. (1980): the soil resource: origin and behaviour. springer, new york, 281 p. kempe, u., götze, j., dombon, e., monecke, t. & poutivtsev, m. (2012): quartz regeneration and its use as a repository of genetic information.– in: götze, j. & möckel, r. (eds.): quartz: deposits, mineralogy and analytics. springer verlag, 331–355. doi: 10.1007/978-3-642-22161-3_15 klepikov, i.v., vasilev, e.a. & antonov, a.v. (2022): regeneration growth as one of the principal stages of diamond crystallogenesis.– minerals, 12, 327. doi: 10.3390/min12030327 kovačić, m., horvat, m., pikija, m. & slovenec, d. (2011): composition and provenance of neogene sedimentary rocks of dilj gora mt. (south pannonian basin, croatia).– geol. croat., 64/2, 121–132. doi: 10.4154/gc.2011.10. kravchenko, y., rogovska, n., petrenko, l., zhang, x., song, c. & chen, y. (2012): quality and dynamics of soil organic matter in a typical chernozem of ukraine under different long-term tillage systems.– can. j. soil sci., 92/3, 429–438. https://doi.org/10.4141/cjss2010-053 krupenykov, i.a. (2008): chernozems. appearance, perfection, tragedy degradation, path of protection and renaissance [in russian].– pontos, kishineu, 288 p. łabaz, b. , waroszewski, j., dudek, m., bogacz, a. & kabala, c. (2022): persistence of arable chernozems and chernic rendzic phaeozems in the eroded undulating loess plateau in central europe.– catena, 216, 1–13. doi: 10.1016/j. catena.2022.106417 łabaz, b., kabala, c., dudek, m. & waroszewski, j. (2019): morphological diversity of chernozemic soils in south-western poland.– soil science annual, 70/3, 211–224. doi: 10.2478/ssa-2019-0019 łabaz, b., musztyfaga, e., waroszewski, j., bogacz, a., jezierski, p. & kabala, c. (2018): landscape-related transformation and differentiation of chernozems – catenary approach in the silesian lowland, sw poland.– catena, 161, 63–76. doi: 10.1016/j.catena.2017.10.003 marković, s.b., vandenberghe, j., perić, z.m., filyó, d., bartyik, t., radaković, m.g., hao, q., marković, r.s., lukić, t., tomić, n., gavrilov, m.b., antić, a., cvijanović, i. & sipos, g. (2023): local differentiation in the loess deposition as a function of dust source: key study novo orahovo loess paleosol sequence (vojvodina, serbia).– quaternary, 6/1, 23. doi: 10.3390/quat6010023 moore, d. & raynolds, r. (1997): x-raj diffraction and the identification of and analysis of clay minerals (2nd ed.).– oxford university press, new york, 378 p. munsell soil color book (2013): munsell soil color charts with genuine munsell color chips.– macbeth division of kollmorgem instruments corporation, new windsor. mutić, r. (1990): korelacija kvartara istočne slavonije na osnovi podataka mineraloško-petrografskih analiza [correlation of the eastern sla vonian quaternary deposits based onthe mineralogical and pet rological analyses (eastern croatia) – in croatian].– acta geol. 20/2, 1–52. nejgebauer, v. (1951): vojvođanski černozem – njegova veza sa černozemom istočne i jugoistočne europe i pravac njegove degradacije [vojvodina chernozem its connection with the chernozem of eastern and southeastern europe and the direction of its degradation – in serbian].– naučni zbornik matice srpske, 1, 1–78. nejgebauer, v., vuchich, n., milkovich, n. (1983): the jugoslavian chernozem.– počvovedenje, 9, 22–32. pamić, j. & pikija, m. (1987): badenian andesites and pyroclastics from baranja in northern croatia (yugoslavia).– acta geol. hung., 30/1-2, 111–132, budapest. peel, m.c., finlayson, b.l. & mcmahon, t.a. (2007): updated world map of the köppen–geiger climate classification.– hydrol. earth syst. sci., 11/5, 1633–1644. doi: 10.5194/hess-11-1633-2007 perčec tadić, m., pasarić, z. & guijarro, j.a. (2023): croatian high-resolution monthly gridded dataset of homogenised surface air temperature.– theor. appl. climatol., 151, 227–251. doi: 10.1007/s00704-022-04241-y pernar, n. (2017): tlo, nastanak, značajke, gospodarenje [soil, formation, characteristics, management – in croatian].– udžbenik sveučilišta u zagrebu, 799 p. pilar, d. (1875): podravina, đakovština i dilj gora [podravina, đakovo area and dilj gora mt. – in croatian].– rad jazu, 33,38–57, zagreb. pozniak, s. (2019): chernozems of ukraine: past, present and future perspectives.– soil science annual, 70/3, 193–197. doi: 10.2478/ssa-2019-0017 radaković, m.g., gavrilov, m.b., hambach, h., randall schaetzl, j., tošić, i., ninkov, j., vasin, j. & marković, s.b. (2019): quantitative relationships between climate and magnetic susceptibility of soils on the bačka loess plateau (vojvodina, serbia).– quatern. int., 502/part a, 85–94. doi: 10.1016/j.quaint.2018.04.040 roeschmann, g., ehlers, j., meyer, b. & rohdenburg, h. (1982): paläoböden in niedersachsen, bremen und hamburg [paleosoils in lower saxony, bremen and hamburg – in german].– geologisches jahrbuch. f, 14, 255–309. romić, m., bragato, g., zovko, m., romić, d., mosetti, d., galović, l. & bakić, h. (2014): the characteristics of cultivated soils developed from coastal paleosand (korčula island, croatia).– catena, 113, 281–291. doi: 10.1016/j.catena.2013.08.009 rubinić, v., galović, l., husnjak, s. & durn, g. (2015): climate vs. parent material – which is the key of stagnosol diversity in croatia?.– geoderma, 250– 261. doi: 10.1016/j.geoderma.2014.11.029 rubinić, v., galović, l., lazarević, b., husnjak, s. & durn, g. (2018): pseudogleyed loess derivates the most common soil parent materials in the pannonian region of croatia.– quatern. int., 494, 248–262. doi: 10.1016/j. quaint.2017.06.044 scheffer f. & schachtschabel p. (2002): lehrbuch der bodenkunde. 15. auflage [textbook of soil science. 15th edition – in german].– spektrum akademischer verlag, heidelberg, 593 p. slovenec, d., belak, m., mišur, i., šegvić, b. & schuster, r. (2020): the early paleozoic cumulate gabbroic rocks from the southwest part of the tisza mega-unit (mt. papuk, ne croatia) evidence of a gondwana suture zone.– int. j. earth sci., 109/6, 2209–2233. doi: 10.1007/s00531-020-01896-8 šandor, f. (1912): istraživanja prapora iz vukovara, bilogore i sa rajne (prethodne vijesti) [investigations of loess from vukovar, bilogora and the rhine river (previous news) – in croatian].– vijesti geol. povjerenstva, 2, 103–107, zagreb. šegvić, b., slovenec, d. & badurina, l. (2022): major and rare earth element mineral chemistry of low-grade assemblages inform dynamics of hydrothermal ocean-floor metamorphism in the dinaridic neotethys.– geol. mag., first view, 1–27. doi: 10.1017/s0016756822001030 škorić, a. (1960): degradacija černozema u hrvatskoj [degradation of chernozem in croatia – in croatian].– poljoprivredno znanstvena smotra, 17, 187–226. g eologia c roatica galović l. et al.: evidence and mineralogical and physico-chemical properties of chernozem and chernozem-like soils in croatia 129 škorić, a. et al. (1977): tla slavonije i baranje [soils of slavonia and baranja – in croatian].– projektni savjet pedološke karte hrvatske, posebna izdanja, knjiga 1, 256 p. škorić, a. (1982): priručnik za pedološka istraživanja [soils of slavonia and baranja – in croatian].– sveučilište u zagrebu fakultet poljoprivrednih znanosti, 57 p. škorić, a., filipovski, g. & čirić, m. (1973): klasifikacija tala jugoslavije [classification of soils of yugoslavia – in croatian].– zavod za pedologiju fakulteta poljoprivrednih znanosti sveučilišta u zagrebu, 72 p. škorić, a., filipovski g. & ćirić, m. (1985): klasifikacija zemljišta jugoslavije [classification of soils of yugoslavia – in croatian].– akademija nauka i umjetnosti bosne i hercegovine, sarajevo, 72 p. špoljar, a., husnjak, s., peremin volf, t. & žibrin, d. (2001): zemljišne kombinacije pedološkog pokrova hrvatske [soil combinations of pedological cover in croatia – in croatian].– agronomski glasnik, 63/1–2, 3–21. terhorst, b., ottner, f. & wriessnig, k. (2012): weathering intensity and pedostratigraphy of the middle to upper pleistocene loess/paleosol sequence of welsaschet (upper austria).– quatern. int., 265, 142–154. doi: 10.1016/j.quaint.2011.08.042 thamó-bozsó, e. & kovács, l. (2007): evolution of quaternary to modern fluvial network in the mid-hungarian plain, indicated by heavy mineral distributions and statistical analysis of heavy mineral data.– in: mange, m., wright, d. (eds.): heavy minerals in use. developments in sedimentology, elsevier, amsterdam, 58, 491–514. doi: 10.1016/s0070-4571(07)58019-2 thamó-bozsó, e., kovács, l.o., magyari, á. & marsi, i. (2014): tracing the origin of loess in hungary with the help of heavy mineral composition data.– quatern. int., 319, 11–21. doi: 10.1016/j.quaint.2013.04.030 trifunović, s. (1985): osnovna geološka karta sfrj 1:100.000. tumač za list odžaci l34-87 [basic geological map of sfry 1:100.000, geology of the ođaci sheet – in croatian].– geološki institut beograd i nafta-gas novi sad (1984), sav. geol. zavod, beograd. 54 p. újvári, g., kok, j.f., varga, g. & kovács, j. (2016): the physics of wind-blown loess: implicationsfor grain size proxy interpretations in quaternary paleoclimate studies.– earth sci. rev., 154, 247–278. doi: 10.1016/j.earscirev.2016.01.006. újvári, g., varga, a. & balogh-brunstad, z. (2008): origin, weathering, and geochemical composition of loess in southwestern hungary.– quaternary res., 69, 421e437. doi: 10.1016/j.yqres.2008.02.001 újvári, g., varga, a., raucsik, b. & kovács, j. (2014): the paks loess-paleosol sequence: a record of chemical weathering and provenance for the last 800 ka in the mid-carpathian basin.– quatern. int., 319, 22–37. doi: 10.1016/j.quaint.2012.04.004 urumović, k., martinčević lazar, j. & kosović, i. (2017): relations between mineralogical compound and hydrogeological properties of typical finegrained sediments in eastern croatia.– in: posavec, k. & marković t. (eds.): 44th annual congress of the international association of hydrogeologists (iah), book of abstracts, iah, dubrovnik, 146. velde, b. & meunier, a. (2008): the origin of clay minerals in soils and weathered rocks. springer verlag, berlin, 407 p. doi: 10.1007/978-3-540-75634-7 velić, j., dragičević, i. & prelogović, e. (1985): geološki odnosi kvartarnih naslaga okolice erduta (istočna slavonija).– geol. vjesnik, 38, 87–100. vidojević, d., manojlović, m., đorđević, a., nešić, lj. & dimić, b. (2016): organic carbon stocks in the chernozems of serbia. eurosoil, istambul, abstract book, 288. wacha l., galović l., koloszár l., magyari á., chikán g. & marsi i. (2013). the chronology of the šarengrad ii loess-palaeosol section (eastern croatia).– geol. croat., 66, 191–203. doi: 10.4154/gc.2013.18 warr l.n. (2021): ima–cnmnc approved mineral symbols.– mineral. mag., 85, 291–320. doi: 10.1180/mgm.2021.43 whitney, d.l. & evans, b.w. (2010): abbreviations for names of rock-forming minerals, am. mineral., 95, 185–187. doi: 10.2138/am.2010.3371 2016 | 69/2 | 245–253 | 9 figs. | 3 tabs. | www.geologia-croatica journal of the croatian geological survey and the croatian geological society 1. introduction influences on the chemistry of groundwater are numerous. apart from the geological setting and hydrogeological characteristics, groundwater quality can be impacted by anthropogenic influen­ ces. increased population growth rates, intensive agriculture and mining could significantly change the groundwater geochemistry. the groundwater investigation in macedonia as part of the pro­ ject „hydrogeological survey of groundwater in macedonia” was one of the newest projects in this area of research (jovanovski, 2009). in addition, numerous studies were also performed in macedonia and the strumica valley, including a systematic hy­ drogeological investigation in macedonia, performed as part of the framework of the hydrogeological map of sfr yugoslavia, 1:500 000 (ivković et al., 1983). micevski et al. (2005) stu­ died the hydro geothermal potential of the strumica valley. a wa ter quali ty assessment was undertaken of the water resources in the strumica river basin (popovska & geshovska, 2014), and the chemical element composition of water samples from the river vardar (republic of macedonia and greece) and its major tributa ries was also studied (ilić popov et al., 2014). some hydroche mical data were determined in the groundwaters of the pelagonia valley (mirčovski et al., 2015). more recently, the con centration of macro­, micro­, trace and ultratrace elements in some natural waters from eastern and south­eastern macedonia were reviewed by šijakova­ivanova & ambarkova (2015). groundwater in the strumica valley was used mainly in the irrigation system and to a considerably lesser degree as drinking water. the main goal of this investigation was to establish any correlations between various analytes, define their sources (geo­ genic and anthropogenic), present their spatial distribution and investigate the influence of the ilovica mining area on ground­ water composition in the region using multivariate statistics (fac­ tor analyses). ­the­use­of­factor­analysis­to­distinguish­the­influence­ of parent material, mining and agriculture on groundwater composition in the strumica valley, macedonia ivan boev1, ajka šorša2, biljana kovačević3, saša mitrev3 and blažo boev1 1 „goce delčev“ university štip, faculty of natural and technical sciences, bul. krste misirkov, 10-a, p.o. box 210, 2,000, štip, republic of macedonia; (ivan.boev@ugd.edu.mk, blazo.boev@ugd.edu.mk) 2 croatian geological survey, department of geology, sachsova 2, 10,000, zagreb, croatia; (corresponding author: ajka.sorsa@hgi-cgs.hr) 3 ”goce delčev” university štip, faculty of agricultures, bul. krste misirikov, 10-a, p.o. box 210, 2,000 štip, republic of macedonia; (biljana.kovacevic@ugd.edu.mk, sasa.mitrev@ugd.edu.mk) doi: 10.4154/gc.2016.19 abstract determination of groundwater chemistry in the strumica valley was essential given its widespread use for irrigation in the agricultural industry. 224 samples were collected form boreholes forming the dataset for the study. the groundwater chemical composition was examined for selected analytes: as, sr, mn, ni, cu, zn, mo, ba, pb, na, mg, al, k, ca, ti, li, cr, fe, u, caco3, cl-, no3 -, nh4 +, so4 2and po4 3-. the source and internal correlations of the analytes were subjected to multivariate statistical analyses (factor analyses), which yielded 7 factors. geochemical maps of these factors were generated using the kriging method. the groundwater chemistry was predominantly controlled by the geology with some anthropogenic influence due to agriculture and mining, affecting the concentrations and spatial distribution of arsenic, phosphates, sulphates, nitrates and some metals (copper, iron, chromium, lead, nickel, zinc). mining of copper/ gold (molybdenum) in the region of ilovica increased the concentration of al, cu, pb, cr, no3 -, ni, zn, na, k, li and po4 3in groundwater, but only at a local level. 2. study area the republic of macedonia is located in southern europe, in the central part of the balkans, at latitude of approximately 42o north and longitude of 22o east (fig. 1), and covers a geographic area figure 1. study area. article history: manuscript received march 01, 2016 revised manuscript accepted may 31, 2016 available online june 28, 2016 keywords: groundwater, chemistry, factor analyses, strumica, macedonia g eo lo gi a c ro at ic a geologia croatica 69/2246 other to the south, along the border of belasica mountain in the vardar zone (rakikevik et al., 1978, 1980; micevski et al., 2005; fig. 2). the oldest rocks are precambrian high­temperature metamorphites, represented by various gneisses and schists. meta­ morphites and magmatites prevailed in the older palaeozoic. the younger palaeozoic rocks were not found. the mesozoic (juras­ sic) is represented by diabase, granite, granodiorite and rhyolites. the tertiary rocks are comprised of upper eocene volcanogenic sediments, conglomerates and sandstones, dacites and andesites and the pliocene epoch is represented by clays, sands and gravels. the strumica valley is predominantly covered by quaternary sed­ iments: sandy clay, gravel, sands and tufaceous sediments. micevski et al. (2005), on the basis of geophysical data, sup­ posed that the depth of the basin varies from 700 – 1,200 m. the metal occurrences are numerous throughout the inves­ tigated area: around strumica, kukliš, veljuša; the northern stru­ mica drainage basin in kalugerica and poderiš, but most impor­ tantly in ilovica located to the east of the investigated area (rakikevik et al., 1978, 1980; popovska & geshovska, 2014). the copper/gold (molybdenum) mine in ilovica extends over 3,100 hectares (carter, 2007). of 25,713 km2, of which 79% is composed of hills/mountainous areas, 19.1% plains and 1.9% surface water. the strumica valley is located in the south east of macedo­ nia, near the border with bulgaria. the biggest city is strumica, with 45,000 inhabitants. the strumica river flows through the valley and the drainage basin gravitates to the black sea. mace­ donia’s climate is variable with different climatic zones, from continental to mediterranean being represented. the strumica valley has a temperate mediterranean climate, characterized by warm and dry summers and cold wet winters. the temperature varies between 40 °c in summer to ­20 °c in winter (carter, 2007). the annual average rainfall is approximately 547 milli­ metres (jovanovski, 2009), and prevailing winds are from the north­west and south­east. 3. geological, hydrogeological and pedological characteristics the largest part of the investigated area is located in the strumica valley. the valley is a tectonic graben formed in the pliocene be­ tween two parallel faults, one to the north along the border of the ogražden mountain in the serbo­macedonian massif and the figure 2. a geological map of the investigated area (rakikevik et al., 1978, 1980; micevski et al., 2005.) g eologia c roatica boev et al.: the use of factor analysis to distinguish the influence of parent material, mining and agriculture on groundwater composition ... 247 macedonia is divided into four catchments: the vardar, stru­ mica, crni drim and južna morava basins. the catchment area of the strumica river comprises part of the serbo­macedonian massif to the north­east, the strumica valley in the middle and part of the vardar zone to the south­west (popovska, 2014, figs. 2, 3). the importance of groundwater in this area and its use has a long history. according to ivković et al. (1983), a special effort was made in the strumica valley of building hydro meliora­ tion systems which involved digging a number of wells to depths between15 to 250 m. groundwater monitoring in the strumica catchment basin was established in 1953 with 23 piezometric wells, but since 2000 only two of them have been in use. water quality is regulated by the „law on waters” (official gazette of rm 4/98, 1998), and the surface waters (rivers, natural and man­ made lakes) were classified into five classes (official gazette of rm 18/99, 1999). water quality in the strumica basin belongs to classes iii and iv, i.e. water for irrigation and polluted water, re­ spectively. an assessment based on the geochemistry of some natural waters in macedonia including five samples from the strumica valley showed satisfactory levels of water quality (šijakova­ivanova & ambarkova, 2015). fluvisols cover the flood plain surface of the strumica river. these alluvial soils were developed on the proluvium and upper river terrace sediments (maksoil, 2016; fig. 2.). the sampling points were predominantly located at the fluvisol, about 10% were in urban areas, only 6 samples north­west from strumica city at humic calcaric regosol, 2 samples south from bansko city at cambisol and 2 samples north­east from ilovica settlement at leptosol and regosol. land use was observed at corine land cover 2006 (dis­ comap, 2016). the largest part of the investigation was un­ dertaken on non-irrigated arable land and complex cultivation patterns land use categories. land use of the disconti nuous urban fabric, inland marshes, natural grasslands and vineyards covered a smaller part of the area. the sample points are distributed over all land use categories, except for the natural grasslands. 4. materials and methods 4.1. sampling and analysis groundwater samples were collected from 224 boreholes over the field area. water from the borehole was pumped out for 10 minu­ tes by electrical pump. samples were stored in 1 l sterile glass bottles which were washed out several times with water from the borehole before filling to the top in order to exclude air. samples were transferred to the laboratory for plant and environmental protection at the agriculture faculty, ugd­štip, within two hours. unfiltered and untreated samples were used to determine alkalinity within an hour after arrival at the laboratory. the rest of each sample was filtered (mn 640 m de ø125, no. 43 (white ribbon)). one part (500 ml) was treated with 1 ml hno3 (pure trace, sigma) for qualitative and quantitative determination of sulphates and trace elements, 300 ml was treated with 0.6 ml h2so4 (pure trace, sigma) for determination of nitrates and am­ monia. samples were stored in a refrigerator at +4 ºс and tested within two days (johnston, 2007). alkalinity is determined according to the epa method 305.1 (1974a) and expressed as mg/l caco3. for that purpose, 20 ml of the sample, 30 ml distilled water and several drops of methyl ora nge are transferred to a 250 ml erlenmeyer flask for titration with 0.01 m hcl until the colour of white wine (pale yellow). sulphatеs were determined by the colorimetric method us­ ing a spectrophotometer (jenway 6715, uv vis) according to the epa method 375.4 (1978). for this purpose, 20 ml concen­ trated sample was transferred to a 25 ml volumetric flask. then, 1 ml glycol alcohol, 1 ml nacl (60 g/l + 1.25 ml hcl), 1 ml bacl2 (150 g/l) and distilled water was added up to the mark. absorb­ ance was read after 30 minutes at a wavelength of 420 nm. the apparatus was calibrated in five calibration levels in the concen­ tration range of 0.1 – 0.5 mg/l using a sulphates standard for ic (1000 mg/l ± 4 mg/l, fluka analytical). determination of nitrates was undertaken by the colorimet­ ric method using the same spectrophotometer type jenway 6715, uv vis. the concentrated sample was directly transferred into a 2 ml cuvette and the absorbance was read at wavelengths of 220 nm and 275 nm. the apparatus was calibrated in five cali­ bration levels in a range from 1 – 5 mg/l using the nitrate stand­ ard for ic, 1000 mg/l ± 4 mg/l (fluka analytical) (dalmacija & agbaba, 2006). the po4 3­ was stochiometrically determined from the value of p dissolved in the waters with the assumption that all the p is in phosphate forms. p was determined by inductively coupled plasma mass spectrometry (icp – ms), apparatus type agilend 7500 cx. calibration of the apparatus for p is in range from 10 – 100 μg/l. results are expressed as μg/l po4 3­. ammonium ions were determined by the colorimetric method using the spectrophotometer type jenway 6715, uv vis. here, 20 ml of the treated sample was transferred to a 25 ml volumetric flask. then 1 ml of potassium sodium tartrate (25%), 1 ml naoh (7.5%), 1 ml nessler’s reagent and distilled water were add up to the mark. the absorbance was read after 30 minu­ tes at a wavelength of 420 nm. the apparatus was calibrated in five calibration levels in the concentration range of 5 – 30 mg/l using the ammonium standard for ic (1000 mg/l ± 4 mg/l, fluka analytical) (epa, 1974b). qualitative and quantitative determination of trace elements was made by inductively coupled plasma mass spectrometry (icp – ms), using an agilend 7500 cx apparatus. calibration of the apparatus for the total cation and anion content of the elements li, ti, cr, mn, ni, cu, as and pb was in the concentration range from 1 – 10 μg/l. for sr (tot) and ba (tot) the calibration range was from 10 – 100 μg/l and for ca (tot), mg (tot), na and к a cal­ ibration range from 1,000 – 5,000 μg/l was used. multi element standard solutions (periodic table mix 1 for icp, 92091, fluka) were used for calibration of these elements. for calibration of the total oxidation state of mo an agilent standard solution 7500 se­ ries pa tuning 2 (100 mg/l) (cas: 7697­37­2) was used in the range of 1 – 10 μg/l. u was calibrated in the range of 1 – 10 μg/l using an agilent standard solution 7500 series pa tuning 1 (5 mg/l) (7697­37­2). the titanium standard for icp (998 mg/l ± 2 mg/l) was used for calibration of ti (tot) in the calibration range of 1 – 10 μg/l. a chloride standard for icp (1,000 mg/l) was used for calibration of cl (tot) in the range of 1,000 – 5,000 μg/l. the bias ranged from 1% – 10% and precision, expressed as interme­ diate precision was better than 10% for all the analysed elements. 4.2. data processing the analytical data were screened in order to carry out univari­ ate and multivariate (factor analysis) statistical analyses. analyti­ cal results falling below the detection limit (dl; rollinson, 1993) were calculated to half of the dl value for the parti cular element. the geochemical data generally never follow a normal distribution, but for carrying out factor analyses it is essential that g eo lo gi a c ro at ic a geologia croatica 69/2248 all variables are close to it (reimann & filzmoser, 2000). therefore, the data were log­transformed to base 10 logarithms (reimann et al., 2008). factor analysis (fa) of the data was performed to reduce the observed variables and detect possible hidden correlations in the dataset in order to acquire a better un­ derstanding and to simplify the interpretation. the kaiser­meyer­ olkin test (kmo) and bartlett’s test of sphericity were used to estimate data adequacy for factorizing. the eigenvalues greater than 1 were selected (kaiser, 1960). the retained factor load­ ings were rotated by varimax rotation with kaiser normalization to facilitate explanation of the factors. statistical analysis was performed using ibm spss software. the calculated factor scores were stored as a new variable in the database and used for generating geochemical maps in gis software arcgistm using its geostatistical analyst extension. after variogram analyses, the geochemical maps based on the factor score values were generated using the kriging method. the factor scores on the factor maps were classified into 50 classes (one class for two percentiles) to gain a smooth transition from the lowest to the highest values. as a result, the different geogenic and/or anthropogenic influences of the factorized geochemical data could be evaluated. 5. results and discussion table 1. reveals that the range for most analytes proved to be con­ siderable. comparing the mean and median values, it can be seen that the means were notable higher. the descriptive statistics of the data conclusively indicated the great variability of the con­ centration of a particular analyte in the groundwater. the values of the kmo test of 0.722 and bartlett’s test of sphericity < 0.001 showed that the data were adequate for fac­ torization. the 7 factors were retained (those with eigenvalues >1) which explains 70.0 % of the variance. a more detailed over­ view about the factors is given in tables 2. and 3. the influence of a particular analyte to the factor increases by the increasing the value of its factor loading. the biggest impacts have factor loadings greater than 0.5, since lower factor loadings give only some additional explanation about an individual factor. in that sense the factor loadings lower than 0.3 could be ignored. table 2. the eigenvalue and explained variance of retained factors. factor eigenvalue variance (%) cumulative variance (%) 1 3.47 13.9 13.9 2 3.42 13.7 27.6 3 2.79 11.2 38.8 4 2.39 9.6 48.3 5 1.99 8.0 56.3 6 1.87 7.5 63.7 7 1.56 6.2 70.0 the association of analytes within the factor loadings greater than 0.5 for factor 1 were as (0.80), fe (0.74), mn (0.68), so4 2­ (­0.61), ba (0.58) and po4 3­ (0.54). the factor scores were highest in the lower part of the strumica river and at the mouth of the turija and štučka tributaries at robovo, sučevo, bosilovo, ednokućevo, murtino, radovo, turnovo, borievo and monos­ pitovo (tab. 3; figs. 2 & 3). an elevated concentration of arsenic in groundwater was due to weathering and leaching as from the as­rich minerals of magmatic and metamorphic rocks originat­ ing from the serbo­macedonian massif and the vardar zone. the arsenic could partly be transported from the northern part of the strumica river from the rich metal occurrences around areas such as the village of podareš. the permeability of fluvisol and allu­ vial parent material and use of pesticides, fertilizers, sludge and table 1. descriptive statistics of the contents of analyses in the groundwater samples (n=224). element/ion mean median standard deviation range minimum maximum as (mg/l) 20.68 1.91 38.41 209.51 0.08 209.59 sr (mg/l) 252.53 188.32 206.78 1244.18 0.09 1244.27 mn (mg/l) 443.32 166.28 625.84 3600.25 0.01 3600.27 ni (mg/l) 3.38 2.62 2.67 21.28 0.31 21.58 cu (mg/l) 1.38 1.05 1.70 21.45 0.10 21.55 zn (mg/l) 48.88 13.95 155.35 1369.10 2.31 1371.41 mo (mg/l) 17.61 8.52 25.38 165.65 0.52 166.17 ba (mg/l) 28.04 22.60 21.01 127.42 0.55 127.97 pb (mg/l) 0.89 0.49 1.55 16.28 0.06 16.35 na (mg/l) 7.18 6.10 4.94 36.38 0.33 36.71 mg (mg/l) 12.62 9.07 12.44 95.83 0.31 96.14 al (mg/l) 9.96 5.32 21.62 208.96 0.46 209.43 k (mg/l) 11.63 5.48 33.74 353.76 0.68 354.44 ca (mg/l) 47.76 37.97 38.34 405.41 5.77 411.18 ti (mg/l) 154.76 123.16 136.27 1034.49 1.98 1036.47 li (mg/l) 6.05 2.62 9.74 86.00 0.40 86.40 cr (mg/l) 0.79 0.48 0.92 6.04 0.00 6.04 fe (mg/l) 197.19 70.35 364.61 3160.71 5.00 3165.71 u (mg/l) 2.99 0.67 8.91 95.34 0.14 95.49 caco3 (mg/l) 213.56 193.62 138.91 915.04 0.03 915.07 cl(mg/l) 36.54 22.18 52.23 610.11 4.19 614.30 no3 (mg/l) 21.85 2.86 44.01 284.30 0.14 284.44 nh4 + (mg/l) 0.96 0.07 4.63 55.86 0.03 55.89 so4 2(mg/l) 23.73 15.86 35.66 300.25 0.25 300.50 po4 3(mg/l) 0.51 0.16 1.05 7.80 0.00 7.80 g eologia c roatica boev et al.: the use of factor analysis to distinguish the influence of parent material, mining and agriculture on groundwater composition ... 249 manure in the intensive agricultural production increased the concentration of arsenic in both soil and groundwater (mak­ soil, 2016; discomap, 2016). according to kabata­pendias & pendias (2001), in well drained soils and sediments, arsenic leaches out downwards into the lower soil horizons. additionally, irrigation with arsenic loaded groundwater recycles as again to the groundwater. these assumptions suggest that part of the arsenic content is of anthro­ pogenic origin. the geochemical behaviour of other analytes in this factor was close. the colloidal fe and mn oxides are important in the sorption other colloidal substances and ions, such as po4 3­ ion (kabata­pendias & mukherjee, 2007; kabata­pen­ dias & pendias, 2001). ba is associated with k in the mag­ matic rocks, mobilizes during weathering and is easily adsorbed onto mn and fe oxides. the barium ion is mobile in solutions without sulphates as revealed by the negative factor loadings of so4 2­. there were also relatively high negative factor loadings of two more analytes cl­ and u. the lack of these elements indicate that in the geological background there are small amounts of na, ca or mg chlorides or soluble uranium minerals present. the lowest factor scores were recorded in the areas of ban­ sko and banica. the low values were also on the upper flow part of the strumica river, north of the confluence of the jazga and turija rivers and in the ilovica area. the spatial distribution of factor scores of factor 2 is divided by separation lines running north north­east – south south­west which passed through murtino (fig. 4). towards strumica city were located the highest factor scores values while the smallest values were at the opposite part of the investigated area. this was clearly connected with the geology (rakikevik et al., 1978, 1980). the magmatite and metamorphites of the vardar zone near strumica city and beyond in the strumica valley, are composed of rocks which when weathered release to the environment and groundwater, ions with the highest factor loadings, including; mg (0.80), ca (0.75), ti (0.69), cl­ (0.69), mo (0.62), ba (0.54), u (0.46) and so4 2­(0.45) (tab. 3; fig. 4). a large proportion of the analytes have their geological origin in the rocks of the vardar zone and the quaternary proluvium of the upper river terrace, (mainly connected to that zone and partly to the serbo­ macedo­ nian massif), (fig. 2). several metal occurrences were recorded table 3. rotated factor matrix of the factors. analyte factor loading 1 2 3 4 5 6 7 as 0.80 –0.01 –0.26 0.24 –0.04 0.09 0.09 fe 0.74 –0.05 0.20 –0.05 0.02 –0.09 –0.07 mn 0.68 0.11 –0.11 0.43 –0.29 0.06 –0.14 so4 2– –0.61 0.45 0.26 –0.10 0.06 0.07 0.15 ba 0.58 0.54 0.05 0.11 0.32 –0.02 0.02 nh4 + 0.48 0.02 –0.35 0.10 –0.20 –0.36 0.12 mg –0.14 0.80 0.06 0.05 0.20 –0.16 –0.07 ca 0.06 0.75 0.10 0.19 0.35 0.26 –0.00 ti 0.20 0.69 –0.08 –0.13 –0.28 –0.20 0.19 cl– –0.41 0.69 0.30 0.23 0.14 0.18 0.01 mo 0.12 0.62 –0.14 0.21 –0.42 0.03 0.09 u –0.40 0.46 0.24 –0.26 0.11 0.04 0.41 al 0.00 –0.14 0.79 –0.15 0.06 –0.04 0.20 cu –0.16 0.05 0.78 0.04 0.13 0.14 –0.21 pb 0.00 0.06 0.67 –0.15 0.03 –0.19 0.28 cr –0.09 0.20 0.51 0.02 0.15 –0.06 –0.05 caco3 0.17 0.01 –0.11 0.94 –0.08 –0.04 0.02 sr 0.12 0.2 –0.04 0.93 0.11 0.00 0.11 no3 – –0.21 0.17 0.21 –0.07 0.73 0.27 0.22 ni 0.06 0.09 0.49 0.06 0.56 0.13 0.20 zn 0.08 0.07 0.11 0.21 0.54 –0.47 0.04 na 0.14 –0.07 –0.17 –0.01 –0.07 0.76 –0.05 k –0.16 0.09 0.10 0.05 0.26 0.74 0.11 li –0.14 0.06 0.13 0.20 0.19 –0.06 0.81 po4 3– 0.54 0.05 –0.04 –0.07 0.05 0.21 0.57 figure 3. spatial distribution of factor scores of factor 1. g eo lo gi a c ro at ic a geologia croatica 69/2250 including uranium in the rhyolites of the strumica region (rakikevik et al., 1978, 1980). the factor loadings of ba and so4 2­ were almost the same; they are balanced as a result of the presence of sulphates which reduce the mobility of barium. in the south­eastern part of the study area, factor scores were lower, with the lowest in the areas of ilovica and bansko. the high factor scores of al (0.79), cu (0.78), pb (0.67), cr (0.51) and ni (0.49) in factor 3 were recorded in the north­western and south­eastern parts of the investigated area, whereas in the middle zone, factor scores were lower (fig. 5). the high factor score on a line from piperovo – prosenikovo – strumica could be linked with some metal occurrences of copper, iron, chromium, uranium and magnetite in the strumica region and farther north, especially in kalugerica and poderiš (rakikevik et al., 1978, 1980). the highest factor score of this factor was, as expected, in the ilovica region, due to the mining of copper/gold (molybde­ figure 4. spatial distribution of factor scores of factor 2. figure 5. spatial distribution of factor scores of factor 3. g eologia c roatica boev et al.: the use of factor analysis to distinguish the influence of parent material, mining and agriculture on groundwater composition ... 251 num) and numerous lead­zinc (copper) and gold occurrences. the bansko area is well known as a geothermal reservoir and the geo­ logical background of the ilovica and bansko region is relevant to this (fig. 2). factor 4 was characterized by high factor loadings of caco3 (0.94) and sr (0.93) and low mn (0.43) in the region of banica, strumica and dobrejci (fig 6). this part of the vardar zone is defined by the presence of magmatites and metamorphites such as marble, which are good sources of ca and sr (rakikevik et al., 1978, 1980; fig. 2). the lowest factor values were registered in the areas of kukliš, svidovica and bansko. the factor loadings of factors 5 were; no3 ­ (0.73), ni (0.56) and zn (0.54). higher factor scores were noted in the areas of banica – strumica, ilovica, bosilovo, monospitovo and svi­ dovica (fig. 7). apart from the evident geological composition, factor loadings were increased by mining in ilovica and agricul­ figure 6. spatial distribution of factor scores of factor 4. figure 7. spatial distribution of factor scores of factor 5. g eo lo gi a c ro at ic a geologia croatica 69/2252 ter which reduce its mobility and entry into groundwater. another reason is the opposite behaviour of mo compared to most metals, as molybdenum is more mobile in the alkaline environment (salminen et al., 2005). the lowest factor scores were noted in two regions prosenik­ ovo – debila and east of bansko. figure 8. presents the distribution of factor scores of factor 6. factor loadings are high for na (0.76), k (0.74) and zn (­0.47). ture in other locations (rakikevik et al., 1978, 1980; fig. 2; discomap, 2016). a nitrate (no3 ­) in factor 5 with a high factor value in the area of the strumica and banica settlements also probably stems from two types of origin, a natural one and another due to inten­ sive agricultural production. a negative factor loading of mo in factor 5 is a result of the geochemical behaviour of this metal. weathered mo tends to make strong complexes with organic mat­ figure 8. spatial distribution of factor scores of factor 6. figure 9. spatial distribution of factor scores of factor 7. g eologia c roatica boev et al.: the use of factor analysis to distinguish the influence of parent material, mining and agriculture on groundwater composition ... 253 the factor scores were highest in the zone east of bansko and in the ilovica areas. zinc had a positive factor loading in factor 5 where it was correlated with no3 ­ and ni and negative in factor 6 where it was correlated with na and k. the lowest factor scores were observed in the areas of dobrejci, east of petralinci and bosilovo and south­east of the city of strumica. the analytes were geogenic in origin. the last factor with an eigenvalue >1 was factor 7. the fac­ tor loadings in this factor were li (0.81), po4 3­ (0.57) and u (0.41) (tab. 3; fig. 9). a possible explanation for the large variations in factor scores for this factor throughout the investigated is due to some local geological phenomena. in addition, phosphates (po4 3­) may be contributed due to the use of fertilizers and pesticides, septic systems and small amounts of manure. the ilovica region is home to porphyry copper/gold (molyb­ denum) ore which increased the concentration of metals in the groundwater (rakikevik et al., 1978, 1980; carter, 2007). additionally, the high concentration of a number of the studied analytes was increased in groundwater due to intensive mining. this was one of the highest factor scores in the area of ilovica in four factors (3, 5, 6, and 7). the elevated factor loadings in the area were noted by a number of analytes: al, cu, pb, cr, no3­, ni, zn, na, k, li and po4 3­. 6. conclusion performing factor analysis yielded 7 factors with eigenvalues >1 which explained 70.0 % of the variance in the data. factors 1, 2, 3, 4, 5, 6 and 7 explained 13.9, 13.7, 11.2, 9.6, 8.0, 7.5 and 6.2 % of variance, respectively. the chemistry of groundwater in stru­ mica valley was predominantly influenced by the geology, and only some minor additional anthropogenic effects were re­ corded. the clear regional geological background was observed in factors 1, 2, 3 and partly in factors 4 and 5. the last two factors 6 and 7 were affected by more local geological variations. the high factor loading of as in factor 1 could be linked to the ele­ vated concentration of arsenic in groundwater. the observed in­ crease of as was predominantly attributed to the geogenic back­ ground and to a lesser degree due to anthropogenic influences, especially intensive agricultural production. further research is required on this subject. besides arsenic, some nitrate, phosphates and some metals, including cu, pb, cr, ni, zn, li have an anthropogenic origin as a consequence of intensive agriculture production and/or mining. the influence of mining in ilovica on the groundwater in the strumica valley was of a more local nature. references carter, g.s. (2007): technical report on the copper gold resources on the ilovitza project, macedonia on behalf of euromax resources limited.– report for ni 43­ 101, broad oak associates, toronto, ontario, canada. dalmacija, b. & agbaba, j. (eds.) (2006): kontrola kvaliteta vode za piće [quality control of drinking water – in serbian].– prirodno­matematički fakultet, de­ partmant za hemiju, novi sad. discomap (2016): http://discomap.eea.europa.eu/map/eeabasicviewer/?webmap=b 5cbf63906584ef2ac5d29d627faf923 (22.2.2016). epa (environmental protection agency) method 305.1 (1974a): acidity by titration.– approved for npdes. editorial revision 1974. epa (environmental protection agency) method 350.2 (1974b): nitrogen, ammonia (colorimetric, titrimetric, potentiometric distillation procedure).– approved for npdes. editorial revision 1974. epa (environmental protection agency) method 375.4 (1978): sulfate (turbidimetric).– approved for npdes. editorial revision 1978. ilić popov, s., stafilov, t., šajn, r., tănăselia, c. & bačeva, k. (2014): applying of factor analyses for determination of trace elements distribution in water from river vardar and its tributaries, macedonia/greece.– hindawi publish­ ing corporation, the scientific world journal, 2014, 11 p. doi:10.1155/2014/809253 ivković, a., šarin, a. & komatina, m. (1983): tumač za hidrogeološku kartu sfr jugoslavije 1:500000 [eplanation for hydrogeological map of sfr yugoslavia, 1:500000 – in croatian].– savezni geološki zavod, beograd. johnston, d. (2007): epa guidelines: regulatory monitoring and testing ground­ water sampling.– environmental protection agency, 38 p. isbn 978­1­921125­ 48­5. jovanovski, m. (2009): hydrogeological survey on groundwater in macedonia.– gtz project, skopje. https://www.researchgate.net/publication/282612958_hy­ drogeological_survey_of_groundwater_in_macedonia?enrichid=rgreq­ 6d809b4d­970d­4e89­928d­324c897e3ba7&enrichsource=y292zxjqywdlozi 4mjyxmjk1odtbuzoyode2mzg5ntgzmje2njlamtq0nde1otm2odq4 mg%3d%3d&el=1_x_2 (16.2.2016) kabata­pendias, a. & mukherjee, a.b. (2007): trace elements from soil to human.– springer­verlag berlin heidelberg, 561 p. kabata­pendias, a. & pendias, h. (2001): trace elements in soils and plants.– 3rd ed., crc press, boca raton, fl. 403 p. kaiser, h.f. (1960): the application of electronic computers to factor analysis.– edu­ cational and psychological measurement, 20, 141–151. maksoil (2016): http://www.maksoil.ukim.mk/masis/ (22.2.2016). micevski, e., popovski, k. & ligovski, m. (2005): hydrogeothermal potential of the strumica valley with a special review of the bansko locality.– proceed­ ings world geothermal congress, antalya, turkey, 24­29 april 2005. mirčovski, v., boev, b., efremoski, z., šorša, a. & dimov., đ. (2015): hy­ drochemical data for the ground waters in the bitola’s part of the pelagonia valley, republic of macedonia.– geologica macedonica, 29, 1, 15–24. official gazette of republic of macedonia (1998): law on waters.– skopje, no. 4/98. official gazette of republic of macedonia (1999): regulation for clas­ sification of water.– skopje, no. 18/99. popovska, c. & geshovska, v. (2014): water balance model for vulnerability assessment of water resources in strumica river basin.– irrigation & drainage systems engineering, 3, p. 127. doi:10.4172/2168­9768.1000127. rakikevik, t., pendžerovski, j. & kovačevik, m. (1978): osnovna geološka karta sfrj 1:100000, list strumica k34­94 [basic geological map of sfry 1:100000, strumica sheet – in macedonian].– geološki zavod, skopje (1969­1972), savezni geološki zavod, beograd. rakikevik, t., kovačevik, m., radovik, n. & pendžerovski, j. (1980): osnovna geološka karta sfrj 1:100000. tumač za list strumica k34­94 [basic geological map of sfry 1:100000, geology of the strumica sheet – in macedo­ nian].– geološki zavod, skopje, savezni geološki zavod, beograd, 69 p. reimann, c. & filzmoser, p. (2000): normal and lognormal data distribution in geochemistry: death of a myth. consequences for the statistical treatment of geo­ chemical and environmental data.– environmental geology, 39, 1001–1014. reimann, c., filzmoser, p., garrett, r.g. & dutter, r. (2008): statistical data analysis explained.– john wiley & sons, ltd., 362 p. rollinson, h. (1993): using geochemical data: evaluation, presentation, interpre­ tation.– longman group uk limited, england, 352 p. salminen, r., batista, m.j., bidovec, m., demetriades, a., de vivo, b., de vos, w., duris, m., gilucis, a., gregorauskiene, v., halamić, j., heitzmann, p., jordan, g., klaver, g., klein, p., lis, j., locu­ tura, j., marsina, k., mazreku, a., o’connor, p.j., olsson, s.å., ottesen, r.­t., petersell, v., plant, j.a., reeder, s., salpeteur, i., sandström, h., siewers, u., steenfelt, a. & tarvainen, t. (2005): geochemical atlas of europe, part 1, background information, metho­ dology and maps.– geological survey of finland, espoo, 526 p. šijakova­ivanova, t. & ambarkova, v. (2015): geochemical assessment of some natural waters from eastern and south­eastern macedonia.– geologia mace­ donica, 29, 1, 5–14. 2017 | 70/2 | 73–78 | 7 figs. | 3 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the goal of the study is to identify genetically similar deposi­ tional units by separating them with a clustering technique. be­ sides, the study focused on the optimization of the separated sed­ imentary elements by analysing the optimal number of clusters. these separated units reflected in particular the lithological and petrophysical properties. moreover, the analysed rock body does reflect that in the lithification stage of sandstone diagenesis, the applied petrophysical properties were still determined by the depositional genetics. one of the most important consequences of this finding is that the separated units are able to represent depositional facies with some additional parametrized geometry information about spatially extended clusters. the cluster units may be the „cornerstones” as structural ele­ ments of a 3d­facies model. during the spatial visualization, the cluster defined sedimentary elements of deep-water clastic depositional systems and their 3d spatial visualization using parametrization: a case study from the pannonian-basin janina horváth, szabolcs borka and jános geiger university of szeged, department of geology and paleontology, hungary; (th.janina@geo.u-szeged.hu) doi: 10.4154/gc.2017.06 abstract many multivariate statistical techniques have the ability to handle large data sets or a great number of parameters. therefore, these multivariate statistical approaches are widely used in clastic sedimentology for facies analysis. furthermore, most of the techniques which try to separate more or less homogeneous subsets can be subjective. this subjectivity raises several questions about the significance and confidence of clustering. the goal of this study is to optimize cluste­ ring and to evaluate the proper number of clusters needed in order to describe sedimentary and lithological facies through common characteristics. also, with the interpretation of the clusters, the parametrized geometry adds further but quasi-subjective information to a 3d geological model. two assumptions must be met: (1) well­definable geometries must correspond to the architectural elements (2) it is assumed that exactly one sedimentary or lithological facies belongs to each structural element and the flow properties are determined by these structural elements. this approach was applied to the clastic depositional data from a miocene hydrocarbon reservoir (algyő field, hungary) to demonstrate the fidelity of the clustering method yielding an optimum of five cluster facies. the revealed clusters represent lithological characteristics within a (delta fed) submarine fan system. the paper deals with two stressed clusters in particular, showing sinusoid channels which were recognizable and measureable using parametrisation. goal was to use methods which could handle and honour the ge­ ometries of depositional structural elements. the parametrized geometry adds an extra but quasi­subjective information to this 3d geological model. during the clustering two assumptions must be met: (1) well-definable geometries must correspond to the architectural elements (2) it is assumed that exactly one sedi­ mentary or lithological facies belongs to each structural element and the flow properties are determined by these structural ele­ ments. this paper demonstrates the method through a case study. the study area is located in the algyő sub-basin of the pannon­ ian-basin geographically belonging to the great hungarian plain. according to the paper by (grund & geiger; 2011; borka, 2016) this study area was characterized as sequences represent­ ing a prodeltaic submarine fan (fig. 1). article history: manuscript received january 31, 2017 revised manuscript accepted april 24, 2017 available online june 28, 2017 keywords: cluster analysis, deep-water depositional system, geo-object, optimised clustering figure 1. the algyő delta sequences macrosedi men tary model (based on bérczi, 1988). g eo lo gi a c ro at ic a geologia croatica 70/274 this paper deals in particular with the details of the optimi­ zation of the clustering results and their spatial interpretation. hence, the method chapter comprises the following: the param­ eters used, distribution of the data, the problems during the clus­ tering such as the correlation between different parameters, how to define the proper number of separated clusters and the inter­ pretation of spatial clusters. why does this paper focus on these problems? usually it is complicated to determine the adequate number of clusters since the most essential parameter of clustering algorithms is to deter­ mine the number of clusters and the validity of the clustering. clustering is an unsupervised technique so the researcher has lit­ tle or no information about the number of clusters. at the same time, the number of clusters is a required parameter so this is a general problem as old as cluster analysis itself. of course, geo­ logical knowledge about the field and information about the core samples can give a rough number of clusters. in addition, the fol­ lowing questions may arise: does the method have the ability to segregate all groups in the property space or not, are the created subsets adequately „homogeneous” or not? in this case the „ho­ mogeny groups” means that the cluster analysis divides data into groups when the main information in the groups is not the de­ scription of the linked objects, but rather their relationship gan et al., 2007. the most common problem is when we separate too many – however homogeneous – groups, and we are not able to label all of them geologically. in contrast, if we have a small number of clusters, they can be relatively too heterogeneous and in this case, it is also hard to define them geologically. 2. methods 2.1. data pre-processing the clustering technique focused on the determination of litho­ logy and facies based on four variables coming from interpreted well­logs: porosity, permeability, sand and shale contents, and also based on some core samples, which provided additional in­ formation. these core samples were also available from one well, which included continuous data from a thickness interval of about 35 metres. these samples acted as sign­posts in the interpretation of cluster results to define lithofacies. the core analysis was presented by borka (2016). accord­ ing to the core analysis, part of a typical mixed sand­mud sub­ marine fan complex, with quasi­inactive parts (zones of thin sand sheets and overbank), channelized lobes (persistent sandstones in them may denote distributary channels), and a main deposi­ tional channel were revealed. however, due to the low number of core samples it was difficult to extend the lithological informa­ tion to the whole area which contains 141 wells. hence, the inter­ preted logs were used to define the lithology types and facies in the case of clustering. usually clustering does not require normal transformation but most clustering algorithms are sensitive to the input para­ meters and to the structure of the data set. the clustering may be more efficient if a good structure exists for the transformed variable, which can approximate the symmetric distribution. it should be close to symmetry prior to entering cluster analysis (templ et al., 2006). significant skewness could be measured in the dis­ tribution of the variables, especially in the shale content and per­ meability (fig. 2 base on eq.1.). a principal component analysis (pca) was applied as pre-processing for the clustering which also required a normal distribution. y x= = + − ≠ + =      a aa a a a a (x ) log(x ) 2 2 1 1 0 0 eq.1 box­cox transformations (box & cox, 1964) of all single variables do not guarantee symmetry of the distribution, but more closeness to them (asante & kreamer, 2015; templ et al., 2006). the applied transformation is a modification of the power transformation by box & cox (1964). this modified power transformation is defined for those cases when variables are negative or equal to zero (eq.1) (sakia, 1992). between the porosity (fiap) and permeability(perm) variables and also the sand (vsnd) and shale volume (vsha) the correlations were significant (coefficient was 0.82 and -0.71). hence, the pca was used to reduce redundancy and create new components (the first component is based on permeability and porosity and the second component is based on sand content and shale content). the goal of the pca method was to create new components which are able to preserve as much of the variance of the original variables as possible. besides this, it was important that the new latent variables are able to combine optimally the weighted ob­ served variables. the first component retained 90.65% of total variance of porosity and permeability and the second component figure 2. results of box-cox transformation. g eologia c roatica horváth et al.: cluster defined sedimentary elements of deep­water clastic depositional systems and their 3d spatial visualization ... 75 also retained a similar large percentage (85.55%) of the total variance of sand and shale volume. the pca required a normal dis­ tributions as well. the clustering was done on the new pca components. one of the neural network clustering (nnc) techniques was applied in the separation of the data set. this clustering method was ap­ plied because nnc was used in similar problems to characteri­ zation of clastic sedimentary environments (e.g. horváth, 2015; horváth & malvić, 2013). in the initial settings the size of the training set was fixed at 70% for all data points. for the validation and testing, 15-15% of the whole set was used, evenly divided. these three subsets were collected by the network in a random way to avoid bias. the learning rate of nnc clustering converged monotonically in the [0,1] interval from the first to the last training cycle. the start value was specified as 0.05 and 0.002 for the end value. the initial number of clusters was determined to be a low value, which resulted in a robust lithofacies. then the number of clusters was increased from value 3 to 8 one by one. (three sub­ set was set as minimum number of clusters in the separation ac­ cording to the core samples. that suggested at least lithofacies – sand­, silt­ and marlstone are separable as clusters in the data set.) but the selection of the proper number of clusters from the possible solutions is not trivial. 2.2. selecting the proper number of cluster solutions a number of authors have suggested various indexes to solve these problems but this means that usually the researcher is confronted with crucial decisions such as choosing the appropriate clustering method and selecting the number of clusters in the final solution. numerous strategies have been proposed to find the right number of clusters and such measures (indexes) have a long history in the literature. the study focused on trying to determine the right number of clusters and to analyse some suggested sum of squares indexes (called wb indexes). the „leave-one out” (loo) classi­ fication method was used in the discriminant function analysis (dfa) as cross validation (asante & kreamer, 2015). to determine the stable number of clusters the dfa with loo cross validation technique was used. a cluster structure was declared stable if dfa predicted at least 80% of the members in each cluster grouping. this threshold was set based on practical observations. overall cross­validated results for each clustering of stable clusters range from 88.0-91.9%. to select the optimal number of clusters in the final solution, a statistics test based on the sum of squares was applied. since a single statistics test method cannot be depended upon, additional methods were used (asante & kreamer, 2015). there are several suggested indexes depending on the sum of squares (eq.2–5): hartigan (1975): ht ss ss b w = log (k) (k) eq.2 explained variance: eta ss ssk b t 2 = (k) eq.3 proportional reduction of error: pre ss ssk w w 2 1 = − (k) (k ) eq.4 f­max statistics: f max ss k ss n k b w − = − − (k) (k) 1 eq.5 eq.5 is equal to the calinsky & harabasz index (1974) which is called the variance ratio criterion (vrc). well­ defined clusters have a large ssb (sum of squares between groups) and a small ssw (sum of squares within groups). the larger the vrc ratio, the better the data partition is. so the opti­ mal number of clusters is determined by maximum vrc. eq.2 is the hartigan index, the so­called crude rule of thumb which is able to estimate the optimal number of clusters with the minimum value of second differences. 2.3. interpretation of the separated clusters the goal of the clustering method is to define „cluster facies” en­ dowed with lithological and petrophysical parameters and the ex­ tension of these separated clusters based on multiple­point (cell­ figure 3. parameters of geoobjects (modified after pyrcz et. al, 2008; maharaja, 2008). g eo lo gi a c ro at ic a geologia croatica 70/276 based), object­based and process mimicking (non cell­bas ed) algorithms. they are able to handle the additional geological in­ formation e.g. geometry. including these additional parameters as inputs is based on the consideration that the flow properties in a clastic reservoir are mostly determined by the geometries and the lithofacies of ancient sub­environments. the latter means that these methods can use only categorical variables, and exactly one lithofacies be­ longs to an ancient sub­environment. the parameter of geometry can be regarded as a quasi­subjec­ tive geological data. although the method of measurement has widespread literature, the final result moderately depends on the practitioner. moreover the defined geometry possesses a distribu­ tion (mean, minimum and maximum values etc.), but it isn’t as veri­ fiable as the parameters and results of variogram-based algorithms. currently several parametric shapes (i.e. geo­bodies, geo­ objects) are available. these geo­bodies are generalized shapes mimicking the true architectural elements. in case of deep­water submarine complexes, the following geo­bodies correspond to the sub­environments: (1) sinusoid ob­ jects: braided or meandering channels (normark, 1970; reading & richards, 1994); (2) lobe objects: channelized or unchannelized lobes (mutti, 1985; reading & richards, 1994); (3) bar objects: mouth­bar at terminus of main depositional valley on the lower part of upper­fan (fgs) (nor­ mark, 1970); (4) ellipsoid objects: crevasse splays attached to channels (pyrcz et. al, 2008; maharaja, 2008). figure 3 shows the measureable parameters of these geo­ bodies. sinusoid geometry should be characterized by: amplitude, wavelength, width, thickness and sinuosity (ratio of true stream­ line length (on the interval of wavelength) and wavelength) of the geo-body. lobe geometry: mouth (x1), width (x2), length to largest width (y1), total length (y2), thickness (h) of the geo­body. bar geometry: width (x), length (y) and thickness of the geo­body. ellipsoid/ellipse geometry: semi­principal­axes (x, y, z) of a tri­ axial ellipsoid. 3. results 3.1. results of clustering optimization the analysis of cluster stability by dfa has eventuated in several stable cluster results (thresholds in excess of 80%); however, ac­ cording to cross validation the 5 cluster solution was determined to be optimal. based on loo, 91.9% of the cross-validated group ed cases are correctly classified. the analyses of differences reduction between training error and validation error also showed the same optimum. the difference­plot (fig. 4­a) reached the el­ bow point at the case of the five cluster solution. in practice the error rate was acceptable if it was appropriately low and good fit (the training­test­validation error rate approximated each other but the validation error was slightly higher than the training error). in addition, the plot of hartigan values (fig. 4­b) and f-max(f) values (fig. 4-c) determined a similar ’best fit’ in the case of the five cluster solution. from the explained variance values etak 2 , the three cluster solution explained 68% of the variance in the dataset; the four cluster solution explained ~78% and so (tab. 1). the table shows that the increment in the proportional reduction of error etak 2 significantly stopped from cluster five. also the prek 2 values sharply decreased from cluster five. 3.2. interpretation of clusters according to the optimality analysis the five cluster solution was approved. during the interpretation of these five clusters they were also matched to the lithological description of core samples (fig. 5). in figure 5 the 0-cluster facies (black colour in the litho­ facies from nnc) shows the impermeable units which were omit­ ted from the analyses. according to this comparison – between the lithofacies coming from clusters and genetic lithofacies com­ ing from core samples – together with the statistical characters (tab. 2) the clusters were labelled: (1) siltstones and marls, inter­ bedded sandstones; (2) spatially dispersed, low permeability sandstones; (3) alternation of siltstones and sandstones; (4) silty sand; (5) massive sandstones. of course, the goal was not to define „cluster facies” as sim­ ple lithological types. the spatial extension of clusters can also show well-defined depositional geometries. 2 out of the 5 clusters were chosen with the highest porosity, sand­content and permeability values (clusters 4 and 5). table 2 summarized the group average of two clusters chosen from the five (clusters 4 and 5). the purpose of the visualization was to examine what geometries are shown by clusters 4 and 5. a quasi-3d model (flatted to the impermeable argillaceous marlstone seal) was constructed by voxler 3’s facerender module. in this case cluster 4 and 5 show two sinusoid geo­bodies at 13 me­ tres beneath the seal (fig. 6). direct measurement isn’t available in voxler 3, so from the same depth, sand and porosity contour maps using kriging estimation were used for the parametrization. the two results show good similarity (fig. 6), although one is based on discrete values, and the other is based on continuous figure 4. a) difference plot based on nnc; b) plot of hartingan indexes, c) f-max(f) plot table 1. test statistics results for estimating the number of clusters. no.clust. 3 4 5 6 7 8 prek 2 0.681758 0.782905 0.848698 0.867727 0.878515 0.904526 etak 2 not defined 0.317831 0.304513 0.123945 0.081557 0.214392 g eologia c roatica horváth et al.: cluster defined sedimentary elements of deep­water clastic depositional systems and their 3d spatial visualization ... 77 figure 5. comparison of nnc lithofacies (right sequence) with genetic lithofacies (left sequence) and lithofacies based on grain-size distribution (middle sequence) (based on borka, 2016). figure 6. picture ‘a’ shows two sinusoid geo-objects related to clusters 4 and 5; picture ‘b’ shows the same shapes in a sand-content contour map. the two slices are from the same depth, at 13 metres beneath the seal. g eo lo gi a c ro at ic a geologia croatica 70/278 variables. therefore, measurement on the contour maps was valid. the measured parameters are shown in figure 7. the geometric values are summarized in table 3. the sinu­ soid geo­objects could be well tracked through approximately 45 slices i.e. contour maps (0.4 metres/1 slice). this means that thicknesses of both of the bodies are 18 metres (0.4 m x 45). core samples of well­a were available from this depth. these can be characterized by massive, structureless fine sand­ stones with ripped intraclasts. they are deposits of sandy debris figure 7. notations with number 1 and 2 belong to the right sinusoid geo-object, while 3 and 4 belong to the left sinusoid geo-object; a – amplitude, w – width, wl – wavelength, s – length of streamline table 3. measured values of the sinusoid geo-objects dimension: meter, except the sin (ratio). right geobody ab br ev ia tio ns a – amplitude a1 a2 wl1 w1 w2 s1 sin th1 w – width 637 775 2156 496 685 2935 1.36 18 wl – wavelength left geobody s – length of streamline a3 a4 wl3 w3 w4 s3 sin th3 th – thickness 310 309 1658 277 286 2358 1.42 18 sin – sinuosity table 2. mean of clusters 4 & 5 based on the original data. cluster-4 cluster-5 por (%) 18.39 20.25 perm(md) 32.24 87.16 vsha (%) 15.30 8.79 vsnd (%) 65.93 71.23 flows (shanmugam, 2006) related to distributary channels or the proximal part of lobes. the gr and sp logs show cylindrical shapes which usually denotes channels (reading & ri­ chards, 1994). 4. summary the study demonstrated that the transformed variables by the box-cox and pca process reduced the impact of skewness and the redundancy in variables to avoid misclassification. the nn clustering with the final settings is validated using the dfa loo method. members in each cluster grouping were validated by over 80% prediction. evaluation of optimal cluster solution relied on more wb indexes. all of them determined the „best fit clus­ tering“ with a five number of clusters solution. also, it is represented that in a case of mature field (dense hard data) ’optimized’ clusters (i.e. lithofacies) can show geomet­ ric features. clusters with the highest porosity, permeability and sand content – which may denote the most active part of the sub­ marine fan – correspond to a sinusoid structural element (i.e. channel). the parameters of this geo­object can be used as input data of multiple­point or object based simulations. acknowledgement this paper was supported by the new national excellence program of the ministry of human capacities. references asante, j. & kreamer, d. (2015): a new approach to identify recharge areas in the lower virgin river basin and surrounding basins by multivariate statistics.– mathematical geosciences, 47/7, 819–842. doi: 10.1007/s11004-015-9583-0 bérczi, i. (1988): preliminary sedimentological investigation of a neogene depression in the great hungarian plain.– in: royden, l.h., & horváth, f. (eds.): the pannonian basin: a study in basin evolution, aapg memoir, 45, 107–116. borka, sz. (2016): markov chains and entropy tests in genetic-based lithofacies analy­ sis of deep-water clastic depositional systems.– open geosci., 8, 45–51. doi: 10.1515/geo­2016­0006 box, g.e.p. & cox, d.r. (1964): an analysis of transformations, journal of the royal statistical society, series b, 26, 211–252. calinski, t. & harabasz, j. (1974): a dendrite method for cluster analysis, com­ munications in statistics, 3, no. 1, 1–27. doi: 10.1080/03610927408827101 gan, g., ma, c. & wu, j. (2007): data clustering: theory, algorithms, and applica­ tions, society for industrial and applied mathematics (siam), philadelphia, penn­ sylvania, 466 p. doi: 10.1137/1.9780898718348 grund, sz., & geiger, j. (2011): sedimentologic modelling of the ap-13 hydrocarbon reservoir, central european geology, 54/4, 327–344. doi: 10.1556/ceuge­ ol.54.2011.4.2 hartigan, j.a. (1975): clustering algorithms– john wiley and sons, inc., ny, usa 351 p. horváth, j. (2015): depositional facies analysis in clastic sedimentary environments based on neural network clustering and probabilistic extension.– unpubl. phd the­ sis, university of szeged, 118 p. horváth, j. & malvić, t. (2013): characterization of clastic sedimentary environ­ ments by clustering algorithm and several statistical approaches – case study, sava depression in northern croatia.– central european geology, 56/4, 281–296. maharaja, a. (2008): tigenerator: object­based training image generator, computers and geosciences.– elsevier, 34, 1753–1761. doi: 10.1016/j.cageo.2007.08.012 mutti, e. (1985): turbidite systems and their relations to depositional sequences.– in: zuffa, g.g. (ed.): provenance of arenites. d. reidel publishing company, 65–93. doi: 10.1007/978-94-017-2809-6_4 normark, w.r. (1970): growth patterns of deep sea fans. aapg bulletin, 54, 2170–2195. pyrcz, m.j. & deutsch, c.v. (2014): geostatistical reservoir modelling.– oxford university print, 2nd edition, university of oxford, 448 p. pyrcz, m.j., boisvert, j.b. & deutsch, c.v. (2008): a library of training images for fluvial and deepwater reservoirs and associated code. computers and geosciences, elsevier, 34, 542–560. doi: 10.1016/j.cageo.2007.05.015 reading, h.g. & richards, m. (1994): turbidite systems in deep­water basin mar­ gins classified by grain size and feeder system.– aapg bulletin, 78, 792–822. sakia, r.m. (1992): the box­cox transformation technique: a review.– the statistician, 41, 169–178. doi: 10.2307/2348250 shanmugam, g. (2006): deep-water processes and facies models: implications for sandstone petroleum reservoirs.– elsevier, 1st ed., amsterdam, the netherlands, 498 p. templ, m., filzmoser, p. & reimann, c. (2006): cluster analysis applied to re­ gional geochemical data: problems and possibilities.– research report­cs­2006­5, vienna university of technology, 39 p. 2018 | 71/2 | 105–111 | 4 figs. | 2 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction hydrogeological maps were considered useful basic documents with the increasing demand for water before the middle of the 20th century, particularly in the industrialized countries, that called for a rational planning of water resources to serve agriculture, industry and the public supply. consequently, compilation of hydrogeological maps at various scales and for various purposes commenced by 1940. since then, more and more areas in more and more countries have been covered by hydrogeological maps, but large land surfaces of the earth have still not yet undergone detailed and systematic hydrogeological mapping (struckmeier & margat, 1995). to reflect new advances of hydrogeological mapping in dif­ ferent periods, iah paid great efforts to develop legends and guidelines for the compilation of hydrogeological maps. several editions of the legends were published, such as a draft legend published by unesco in 1963 (anon, 1963), a new legend pub­ lished by the institute of geological sciences (london) iahs, iah and unesco in 1970 (anon, 1970), a revised legend pub­ lished by unesco in 1983 (struckmeier et al., 1983) and common and different features of chinese and italian hydrogeological mapping guidelines wu aimin1, martarelli lucio2, ma rong3, wang huang1, yang huifeng3 and bu hua4 1 china geological survey, beijing, china (waimin@mail.cgs.gov.cn) 2 geological survey of italy-ispra, rome, italy; (lucio.martarelli@isprambiente.it) 3 institute of hydrogeology and environmental geology-cags, shijiazhuang, china 4 south-shandong institute of geo-engineering exploration, yanzhou, china doi: 10.4154/gc.2018.07 abstract the definition of common international guidelines for the compilation of high quality hydrogeological maps has been attempted from the second half of the last century for hydrogeologists, to solve the lack of uniformity among national guidelines due to the various geological-hydrogeological and climatic situations of different countries worldwide. with this aim, the china geological survey and the geological survey of italy-ispra are undertaking cooperative research in implementing 1:50,000 scale hydrogeological survey and mapping at selected sites in both countries. the project intends to develop a new generation of hydrogeological and groundwater resource maps with descriptive effectiveness and consistency with field survey data. the project will promote improvements of technologies in hydrogeological survey and mapping of the two countries and might even be agreed at a wider international level. chinese and italian hydrogeological guidelines have similar aspects as well as concerns: 1) the undertaking of field surveys at the 1:50.000 scale and more detailed (1:25000) scale; 2) building of a hydrogeological database; 3) publication of the official map in both paper and electronic form; 4) inclusion of several small scale maps inlayed at the margin of a main map in the hydrogeological map layout; 5) comparable level in required survey quota. furthermore, more attention will be paid to a 3d map, conceptual model, aquifer structure, groundwater cycle and hydrogeological parameter description. in contrast, the most important difference regards the following. the hydrogeological mapping guidelines of italy have integrated specifications for both survey and mapping, i.e. they deal with a structural layout characterized by survey contents followed by mapping contents and reflect a technical route of surveying for mapping. in contrast, there are no mapping contents in the current hydrogeological guidelines of china and these then needed to be formulated. the italian guidelines could provide important references for china in legend organization, mapping rules, survey quota and so on. finally, the collaboration between china and italy is of great significance for the two ancient civi­ lized countries sharing the “one belt and one road” international initiative. a final version of the international legend for hydrogeological maps published by iah in 1995 (struckmeier & margat, 1995). all of these extensively promoted developments of hydro­ geological mapping worldwide and were successful. however, these guides and legends are mainly suitable for the compilation of general hydrogeological maps at small­scale, e.g. 1:200.000, 1:500.000 and less. many medium­ and large­scale special purpose maps have been developed at national level, or for selected areas within countries from the second half of the last century. therefore, the definition of common international guide­ lines for the compilation of high quality hydrogeological maps at medium­ and large­scale has been attempted by hydrogeologists globally, in attempts to solve the lack of uniformity among na­ tional guidelines due to the various geological­hydrogeological and climatic situations of different countries. hydrogeological map production in italy is extensive (e.g., giannotti et al., 1970; pietracaprina et al., 1980; boni et al., 1986; centamore et al., 1991; boscherini et al., 2005; celico et al., 2005; civita et al., 2005) and includes article history: manuscript received december 23, 2017 revised manuscript accepted may 03, 2018 available online june 21, 2018 keywords: hydrogeology, hydrogeological mapping, comparative research, china, italy g eo lo gi a c ro at ic a geologia croatica 71/2106 studies carried out for many different purposes and at very dif­ ferent reference scales. two sheet maps (servizio geologico d’italia, 1973 and 1976) represent early attempts of realizing hydrogeological maps combining hydrogeological thematic elements with geo­ logical contents. after 1989, when the new italian geological and geothematic mapping project (carg project, 1:50.000 scale) be­ gan, the first official hydrogeological guidelines to field survey and mapping for the hydrogeological map of italy at 1:50.000 scale were issued by the geological survey of italy (quaderni, serie iii, guidance n.5; servizio geologico nazionale, 1995). they are composed of a standard legend accompanied with technical specifications about data collection. nevertheless, they were thought of for manual mapping work, not yet computer assisted. these italian hydrogeological mapping guidelines fol­ low the general specifications of the international legend for hy­ drogeological maps, though they adopt specific standards due to the different reference scales and the peculiar and diverse geo­ logical and hydrogeological features of the italian territory. only one official hydrogeological map sheet (servizio geolo­ gico d’italia, 1993) was issued following a preliminary ver­ sion of the 1995 guidelines, but many non­standard hydrogeo­ logical maps published in italy referred to them with regard to the main aspects. in 2008 the geological survey of italy (scalise & mar­ tarelli, 2008) promoted field testing of the “guidance n.5” and new guideline proposals were discussed. these tests also started the discussion about digital mapping by the organization of thematic informative layers constituting a gis. according to these new guideline proposals, four sheet maps are in preparation and a sheet map (conte et al., 2016) and a not standard size map (la vigna & mazza, eds., 2015) were realized. through these field practices, new guideline specifications were gradually improved and an english unpublished provisional version of the hydrogeological map of italy – guidelines to survey and map­ ping was produced in 2016. although china is one of the earliest countries in the world to develop and use groundwater, organized, scientific hydrogeo­ logical mapping in china did not start until 1949 when the peo­ ple’s republic of china was founded. china’s hydrogeological mapping can be divided into 2 stages: (1) the period of the mini­ stry of geology and mineral resources; and (2) the period of the china geological survey, ministry of land and mineral re­ sources. for the period of ministry of geology and mineral re­ sources from 1949 to 1998, the basic scale of regional hydrogeo­ logical maps has been adopted at 1:200.000. in remote districts or high mountainous regions, where the implementation of geo­ logical investigation was difficult, the prevailing scales were 1:500.000 to 1:1.000.000. in the 1950s, the hydrogeological map contained more geological factors and fewer hydrogeological ele­ ments. people who are not specialists in this subject will have some difficulties in understanding it. conforming to the princi­ ples of simplicity, clarity and practicality, the methods of compi­ lation were improved in the 1960s. emphasis was placed upon the water storage capacity of water­bearing formations. in the 1970s, according to the standardized international legends (anon, 1970) and actual situation in china, the methods of the hydrogeological survey and mapping were continually improved. a set of technical standards for the hydrogeological survey, re­ ferring to the plain areas, mountainous areas, karst areas, coastal area, etc. (geological bureau of national plan­ ning commission, 1974, 1975a, 1975b, 1975c, 1978) were developed. in 1993, a new legend and colour standard for the comprehensive hydrogeological map was published (geolo­ gical bureau of national planning commis­ sion, 1974, 1975a, 1975b, 1975c, 1978; state bureau of technical supervision, 1993). with respect to the second stage, the basic scale of the re­ gional hydrogeological maps has been changed to 1:50.000, from 1999 to the present. to adapt to the new demands of the economic and social developments and the ecological and environmental protections to geological works, four projects on a hydrogeolo­ gical mapping scale of 1:50.000 have been undergone. the first is the groundwater exploration and water supply demonstration in water shortage regions; the second is the investigation and assessment of hydrogeological and environmental geology in karst regions; the third is the investigation and assessment of hydrogeology in key energy bases; and the fourth is the inves­ tigation and assessment of hydrogeological and environmental geology in key urban agglomerations. to obtain high qualities of hydrogeological maps, cgs paid tremendous efforts to formulate a specification of hydrogeologi­ cal survey at the scale of 1:50.000. china has a territory of 9.6 million km2 with very different hydrogeological characteristics, which are difficult to portray on maps in a set of simple legends and symbols. although the formulation of the specification com­ menced in 2006, it was not promulgated until 2015. it experienced complicated procedures, including pre­research, draft version, field trial, revision and improvement (wang guiling et al., 2008; wen dongguang et al., 2012; wu aimin et al., 2015). in 2015, the specification for the hydrogeological survey at 1:50.000 promulgated and became effective as a professional standard ­ dz/t 0282­2015 (the ministry of land and mineral resources, 2015). only 2.3% of the whole territory has been completed for this round of hydrogeological mapping at the scale of 1:50.000. for all the map sheets that were completed after 2015, the new speci­ fication for hydrogeological mapping was followed; the map sheets that were completed from 2012 to 2014 contributed to the field trial of the specification and to its improvement; and map sheets that were completed before 2011 followed the old specifi­ cations for hydrogeological mapping. currently, the china geological survey (cgs) and geolo­ gical survey of italy (ispra) have respectively implemented projects on hydrogeological survey and mapping at a scale of 1:50.000 and, according to this issue, are carrying out coopera­ tive research aimed at improvements of the technologies and methods. the cooperative project intends to develop a new gene­ ration of hydrogeological and groundwater resource maps with descriptive effectiveness and consistency with field survey data. the objectives are: (1) to research the methodology of the 1:50.000 scale hydrogeological survey and mapping; (2) to conduct demonstration and comparative studies on the 1:50.000 scale hydrogeological survey and mapping by selecting sites in both countries with similar hydrogeological conditions and test its applicability; (3) to formulate guidelines on a 1:50.000 scale hydrogeological survey and mapping and promote its standardization. among these, it constitutes a cornerstone and starting point for cooperative research to compare common and diverse features of chinese and italian hydrogeological mapping guidelines. the pilot areas are: (1) the luan river plain in the north part of the north china plain, china; (2) the rieti plain, central italy. g eologia c roatica aimin et al.: common and different features of chinese and italian hydrogeological mapping guidelines 107 both pilot areas consist of piedmont alluvial­proluvial fans and plains, share similar hydrogeological conditions, and thus will benefit from collaborative and comparative research. in october 2015, ispra researchers visited china and attended a field survey to the luan river plain; cgs researchers showed the hy­ drogeological survey methods and research findings (fig. 1). in november 2016, cgs researchers visited italy and attended a field survey to the rieti plain; ispra researchers showed some different hydrogeological survey methods, monitoring instru­ ments and mapping findings (fig. 2). the researchers of both countries have had a deeper understanding of the hydrogeologi­ cal survey methods and technical standards of both countries. 2. research methods and results the following describes the research methods and results of the comparison between the hydrogeological map of italy ­ guide­ lines to survey and mapping, english unpublished version 2016 (here in after referred to as the italian guideline) and the specification for hydrogeological survey, dz/t 0282 ­ 2015 (hereinafter referred to as the chinese guideline). they are identified in 5 respects to better demonstrate the common and different features of both guidelines. 2.1. basic requirements in the basic requirement for hydrogeological survey and mapping at 1:50.000 scale, both the chinese and italian guidelines have almost the same concerns including the following: (1) the geographic map in more detailed scale, normally at 1:25.000 scale; (2) building a hydrogeological database; (3) publication of official maps in both paper and electronic form; (4) several small scale maps inlaid at the margin of a thematic map in hydrogeo­ logical map layout; (5) the compilation outline on the specification of the hydrogeological map; (6) more attention paid to a 3d map, conceptual model, aquifer structure, groundwater cycle and hy­ drogeological parameter description. 2.2. general layout of hydrogeological map chinese guideline and italian guideline have mostly the same concerns in the layout of the hydrogeological map. both guidelines stipulate that a hydrogeological map should be composed of the following basic elements: (1) map heading and editorial information, (2) a hydrogeological thematic map, (3) hy­ drogeological cross­section maps, (4) hydrogeological complex columns, (5) hydrogeological perspective and small scale insets, (6) legends and symbols, etc. there are only a few differences between them. for the chi­ nese guideline, legends are placed on the right of the map and hydrogeological complex columns are put on the left; for the ital­ ian guideline, legends are on the left with hydrogeological complex columns on the right. the general layout of the hydrogeological map in the italian guideline is shown in fig. 3. figure 1. hydrogeological survey in china. the luan river near its mouth (left) and alluvial sediments of the luan river plain (right) can be seen in the background. figure 2. hydrogeological survey in italy. the rieti plain landscape (left) and some calcareous rocks cropping out at the rieti plain margin (right) can be seen in the background. g eo lo gi a c ro at ic a geologia croatica 71/2108 2.3. structure tree of legends and symbols the italian guideline comprises eight tables from which to reflect and choose the legend structure and its caption. each table indi­ cates rules and specifications portraying features on the kind of hydrogeological characters expected. (1) table a describes the surface hydrology. it deals with ri­ vers, lakes, wetland, swamps and reservoirs, and also characterizes the attributes of rivers and the relationship between rivers and groundwater. (2) table b describes the groundwater hydrology. it reflects the attributes of groundwater, including groundwater emergences, aquifer features, hydrodynamic features, and hydrochemical features. (3) table c describes hydrogeological complexes distin guis­ h ed on the relative degree of permeability. four degrees of relative permeability were defined (high permeability complexes, ap; intermediate permeability com plexes, mp; scarce permeability complexes, sp; very low perme­ ability complexes, bp) according to parameters including grain size, fissuration index, karst index, specific yield (or annual mean groundwater flow, in m3/a/km2) and in par­ ticular in comparison to the hydrogeological features of adjacent complexes. (4) table d describes the artificial works for water abstrac­ tion. only the main or relevant water supply works, wells and hydraulic works have to be represented on the hydro­ geological map. (5) table e describes the karst area. it is dedicated to the symbols regarding the most significant karst morpholo­ gies such as dolines, sinkholes and caves. (6) table f describes the lithological symbols. this table in­ cludes thirty symbols, which involve sedimentary rock, volcanic rock and metamorphic rock. it emphasizes the sedimentary rock and unconsolidated sediment with stronger water abundance. (7) table g describes the hydrogeological boundaries and other boundary typologies of hydrogeological relevance. this table includes three boundaries: infiltration waters totally or partially pass through the limit; flowing ground­ water passes through the limit under the saturation sur­ face elevation; and the limit occurs at the contact between permeable and impermeable/very low permeable rocks. (8) table h describes hydrogeological complexes. it stipulates how to distinguish hydrogeological complexes by effec­ tive infiltration and transmissivity. for example, according to the effective infiltration, the complexes are distinguished into three types (i.e. covering deposits; sed­ imentary deposits; volcanic and metamorphic rocks) and the covering deposits may also be divided into four groups according to their effective infiltration values. comparison with the italian guideline shows that the chinese guideline does not give the specifications for the compilation of a hydrogeological map. the current chinese guideline is only a hydrogeological survey guideline, rather than a mapping guide­ line. the legend and colour standard for the comprehensive hydrogeological map (state bureau of technical su­ pervision, 1993) can be used for guiding the hydrogeological map, but it is special for the 1:200.000 scale, only partly suitable to 1:50.000 scale. based on the italian guideline and the legend and colour standard for comprehensive hydrogeological map, at present, the china geological survey is formulating a guideline for the compilation of a hydrogeological map at a 1:50.000 scale. a draft version of these guideline proposals has been completed and, according to them, a hydrogeological map draft in a pilot area of china is shown in figure 4. 2.4. field workload quota the chinese guideline defines the field workload quota in a lon­ ger table in detail (table 1), while the italian guideline also de­ fines them in a shorter table in brief (table 2). some work items, such as survey points, water level points and water sampling points, are listed in both guidelines and with comparability in the workload quotas. some work items, such as survey route intervals, geophysical exploration profiles and exploration boreholes, only appear in the chinese guideline. some work items, such as transmissivity/hydraulic conductivity tests, spring/karst inflow­outflow points, river flowrate tests, only appear in the italian guideline. since the aim of the research is not the definition of the best methodology for the acquisition of the aforementioned survey parameters but the necessity of their availability, it is assumed that each parameter listed in both tables 1 and 2 may be estimated by different criteria (e.g.: hydraulic conductivity from grain size, pumping test data, soil mechanic lab tests, etc.; water level measurements by manual or time con­ tinuous data­logging instruments; river flowrate and spring dis­ charge measurements in temporary or permanent stations by vol­ umetric tests, f low meter or other gauging devices; water sampling for chemical analyses by diverse methods; geophysical exploration profiles using various methodologies). the different requirements of field workload quota in the chinese and italian guidelines reflect the different philosophies for hydrogeological survey and mapping in both countries. the chinese guideline pays more attention to the exploration of aquifer structures (and therefore geophysical surveys and exploration boreholes are expressly requested), while the italian guideline pays more attention to the acquisition of hydrogeolo­ gical parameters (transmissivity/hydraulic conductivity, spring/ karst inflow­outflow and river flowrate tests are requested). the chinese guideline reflects the high equipment capability and technological skills available at the cgs. figure 3. a demonstration of hydrogeological map layout. among the basic elements are: map heading and editorial information, a hydrogeological thematic map, hydrogeological cross-sections, hydrogeological complex columns, hydrogeological small scale insets, legends, symbols, etc. g eologia c roatica aimin et al.: common and different features of chinese and italian hydrogeological mapping guidelines 109 in any case, it is finally observed that an opportune assess­ ment on typology and the distribution of surveys for any hydro­ geological mapping purposes is in direct connection with the strategic importance of the groundwater resources of the region which is being mapped. 2.5. items to be surveyed in the chinese guideline, a large number of words are used to de­ fine the common requirements for a field hydrological survey, covering the structure of unsaturated zones, the spatial structure of aquifers and water­bearing formations, parameters of aquifers and water­bearing formations, groundwater system boundary, re­ charge runoff discharge conditions of groundwater, dynamic characteristics of groundwater, chemical characteristics of groundwater, development and utilization of groundwater, envi­ ronmental geological problems related to groundwater, special groundwater. another significant part is used to define the special requirements for a hydrological survey in the plain and basin area, mountain and hilly area, and karst area. the italian guideline deals with a structural layout chara­ cterized by survey contents followed by mapping contents. it re­ flects a technical route in which the field surveying serves as a compilation for the hydrogeological map and the survey contents should tightly grasp the needs of compilation of the hydrogeo­ logical maps. the survey requirements include surface water hy­ drology, groundwater hydrology, characteristics of groundwater hydraulics, characteristics of groundwater chemistry, effective infiltration, groundwater conductivity, etc. 3. next step of the project as a next step, cgs and ispra will jointly compile the hydro­ geological maps for each of the pilot areas using both metho­ dologies, thus adopting the advantages of both sets of guidelines, in accordance with international conventions. the aim is to figure 4. a thematic map demonstration of a hydrogeological map draft in a mapping area of china according to the new compilation proposals at a 1:50.000 scale. the legend symbols can be divided into four groups according to the hydrogeological features they represent. the first group includes 4 that show the productivity of pore aquifers in unconsolidated rocks; 1. flow rate of a single well 300-1000 m3/d; 2. flow rate 100-300 m3/d; 3. flow rate <100 m3/d; 4. flow rate <100 m3/d. the second group shows the productivity of pore-fracture aquifers in clastic rocks and includes 2 symbols; 5. flow rate <10 m3/d; 6. flow rate 10-100 m3/d. the third group shows the productivity of karst cave-fracture aquifers in carbonate rocks and includes 28 symbols; ordovician systems, exposed type: 7. flow rate >5000 m3/d; 8. flow rate 1000-5000 m3/d; 9. the flow rate 300-1000 m3/d; 10. flow rate 100-300 m3/d; 11. flow rate <100 m3/d. ordovician systems, covered type: 12. flow rate >5000 m3/d; 13. flow rate 1000-5000 m3/d; 14. flow rate 100-300 m3/d; 16. flow rate <100 m3/d. upper-middle cambrian system, exposed type: 17. flow rate 10005000 m3/d; 18. flow rate 300-1000 m3/d; 19. flow rate 100-300 m3/d; 20. flow rate <100 m3/d. upper-middle cambrian system, covered type: 21. flow rate >5000 m3/d; 22. flow rate 1000-5000 m3/d; 23. flow rate 300-1000 m3/d; 24. flow rate 100-300 m3/d; 25. flow rate <100 m3/d. lower cambrian system, exposed type: 26. flow rate 1000-5000 m3/d; 27. flow rate 300-1000 m3/d; 28. flow rate 100-300 m3/d; 29. flow rate <100 m3/d. lower cambrian system, covered type: 30. flow rate >5000 m3/d; 31. flow rate 1000-5000 m3/d; 32. flow rate 1000-5000 m3/d; 33. flow rate 100-300 m3/d; 34. flow rate <100 m3/d. the fourth group shows the typical hydrogeological features that influence and control the formation and movement of the regional groundwater and includes 7 symbols; 35. ascending spring; 36. seasonal spring group; 37. boundary of aquifer; 38. groundwater recharge from river; 39. groundwater discharge into river; 40. groundwater flow direction; 41. fault. g eo lo gi a c ro at ic a geologia croatica 71/2110 achieve the goal to translate the hydrogeological setting into a visual representation which can be understood without error and bias by the map user; and more straightforwardly, to develop a profound grasp of the complex hydrogeological situation and to portray it in a clear and easily readable manner on a map. 4. conclusions chinese and italian guidelines have some common features including the graphic map at a scale of 1:50.000, the building of a hydrogeological database, publication of the official map in both paper and electronic form, general layout of hydrogeological map, comparable levels of the amount of survey data required. fur­ thermore, more attention will be paid to a 3d map, conceptual model, the aquifer structure, groundwater cycle and hydrogeo­ logical parameter description. in addition there are also some differences including the guideline structure, some survey content, and some field workload quotas. the most important point is that the italian guideline is an integrated guideline both for surveying and for mapping; while the chinese guideline is only for the hydrogeological survey. the china geological survey is now formulating a hydrogeological mapping guideline at 1:50.000 scale. in the coming years, the cgs and ispra will combine the advantages of the chinese and italian guidelines to establish a new guideline for hydrogeological mapping at 1:50.000 scale, which will benefit both china and italy, as well as other nations around the globe. the collaboration on hydrogeological mapping between china and italy is of great significance for the two ancient civi­ lized countries sharing the “one belt and one road” interna­ tional initiative. acknowledgement this work is jointly supported by the china geological survey and the geological survey of italy–ispra. this paper is dedicated to mr giovanni conte who produced some parts of the draft paper, and who unfortunately died in a traffic accident in january, 2016 in rome. references anon (1963): international legend for hydrogeological maps.unesco, paris, do­ cument ns/nr/20, 32 p. anon (1970): international legend for hydrogeological maps.unesco, paris. cook, hammond & kell ltd., england, 101 p. (text in english, french, spanish and russian). boni, c.f., bono, p. & capelli, g. (1986): schema idrogeologico dell’italia cen­ trale “hydrogeological sketch map of central italy”.memorie società geologica d’italia, 35, 991-1012. boscherini, a., checcucci, r., natale, g. & natali, n. (2005): carta idro­ geologica della regione umbria (scala 1:100.000) “hydrogeological map of um­ bria region (1:100.000 scale)”.giornale di geologia applicata 2. celico, p.b., de vita, p., monacelli, g., scalise, a.r. & tranfaglia, g. (2005): carta idrogeologica dell’italia meridionale scala 1:250.000 “hydrogeo­ logical map of southern italy at 1:250.000 scale”.ispra, rome, italy. centamore, e., panbianchi, g., deiana, g., calamita, f., cello, g., dramis, f., gentili, b. & nanni, t. (1991): ambiente fisico delle marche. geologia, geomorfologia, idrogeologia (scala 1:100.000) “physical environment of marche. geology, geomorphology, hydrogeology (1:100.000 scale)”.re­ gione marche. civita, m., lo russo, s. & vigna, b. (2005): carta idrogeologica schematica del piemonte (nw italia) (scala 1:250.000) “hydrogeological sketch map of piedmont (nw italy) (1:250.000 scale)”.cnr­gndci/politecnico di torino, firenze, italy. conte, g., martarelli, l., monti, g.m., motteran, g., scalise, a.r., serafini, r. & silvi, a. (2016): caratteristiche idrogeologiche dell’area del foglio 348 antrodoco alla scala 1:50.000 “hydrogeological features of the sheet n.348 antrodoco area, 1:50.000 scale”.memorie descrittive della carta geo­ logica d’italia. geological bureau of national planning commission (1974): tech­ nical regulation of regional hydrogeological survey in karst areas.the people’s republic of china, beijing (in chinese). geological bureau of national planning commission (1975a): technical regulation of regional hydrogeological survey in plain areas.the peo­ ple’s republic of china, beijing (in chinese). geological bureau of national planning commission (1975b): technical regulation of regional hydrogeological survey in mountainous areas. the people’s republic of china, beijing (in chinese). geological bureau of national planning commission (1975c): technical regulation of regional hydrogeological survey in coast areas.the peo­ ple’s republic of china, beijing (in chinese). geological bureau of national planning commission (1978): com­ pilation method of comprehensive hydrogeological map.the people’s republic of china beijing (in chinese). giannotti, g.p., lombardi, l. & sido, g. (1970): carta idrogeologica della si­ cilia sud occidentale (scala 1:200.000) “hydrogeological map of south­western sicily (1:200.000 scale)”.comitato nazionale en ergia nucleare – laboratorio geomineralogico. table 1. field workload quota in chinese guideline (unless specified, values refers to number of required survey points per 100 km2). types of survey area survey route interval (km) survey points water level points geophysical exploration profiles (km) unsteady flow pumping tests exploration boreholes water sampling points plain basin simple area 1.7~2.0 40~55 8~10 12~15 1~2 1.5~2 6~8 medium area 1.5~1.7 55~65 10~12 15~18 1~3 2~3 8~12 complex region 1.2~1.5 65~70 12~16 18~20 1~4 3~4 12~26 mountain and hill simple area 1.2~1.5 45~55 6~8 2~5 1~2 1.5~2 4~6 medium area 0.9~1.2 55~80 8~10 3~5 1~3 2~3 6~8 complex region 0.6~0.9 80~120 10~12 4~6 1~5 3~5 8~12 karst region simple area 1.2~1.5 40~60 8~10 2~5 1~2 1.5~2 5~8 medium area 0.9~1.2 60~90 10~14 3~5 1~3 2~3 8~12 complex region 0.6~0.9 90~130 14~18 4~6 1~5 3~5 12~18 table 2. field workload quota in italian guideline (values refers to number of required survey points per 100 km2). types of survey area survey points water level points transmissivity/hydraulic conductivity tests spring/karst inflow-outflow points river flowrate tests water sampling points plain 50~70 20~25 10~15 0~5 20~25 10~15 mountain 50~70 10~15 0~5 30~35 10~15 10~15 karst region 50~70 10~15 0~5 30~35 10~15 10~15 g eologia c roatica aimin et al.: common and different features of chinese and italian hydrogeological mapping guidelines 111 la vigna, f. & mazza, r (eds.) (2015): hydrogeological map of rome – 1:50.000 scale.po.li.graf., pomezia, rome, italy. ministry of land and mineral resources (2015): specification for hy­ drogeological survey 1:50,000.dz/t 0282­2015. the people’s republic of chi­ na (in chinese). pietracaprina, a., dettori, b. & mouton, j. (1980): carta delle risorse id­ riche della sardegna alla scala 1:250.000. schema idrogeologico “groundwater resource map of sardinia at 1:250.000 scale. hydrogeological sketch”.in: “ricerche idriche sotterranee in sardegna”. università degli studi di sassari­cas­ sa per il mezzogiorno, progetto speciale 25. scalise, a.r., martarelli, l. (eds.) (2008): studi sperimentali finalizzati alla car­ tografia idrogeologica “field surveys for the implementation of the hydrogeolo gical cartography”.– memorie descrittive della carta geologica d’italia, lxxxi, 176 p. servizio geologico d’italia (1973): carta idrogeologica alla scala 1:50.000 – f.611 mistretta ”hydrogeological map at 1:50.000 scale – sheet n.611 mistre­ tta”.– ipzs, rome, italy. servizio geologico d’italia (1976): carta idrogeologica alla scala 1:50.000 – f.291 pergola “hydrogeological map at 1:50.000 scale – sheet n.291 pergola”.– ipzs, rome, italy. servizio geologico d’italia (1993): carta idrogeologica alla scala 1:50.000 – f.389 anagni “hydrogeological map at 1:50.000 scale – sheet n.389 anagni”. ipzs, rome, italy. servizio geologico nazionale (1995): carta idrogeologica d’italia 1:50.000. guida al rilevamento e alla rappresentazione “hydrogeological map of italy 1:50.000. guideline to survey and mapping”.quad. sgn n.5, serie iii, ipzs, rome, italy. state bureau of technical supervision (1993): legend and color standard for comprehensive hydrogeological map.gb/t 14538­93. the people’s repub­ lic of china, beijing (in chinese). struckmeier, w.f., monkhouse, r.a., jelgersma, s. & gilbrich, w.h. (1983): international legend for hydrogeological maps (revised edition).– un­ esco, paris. struckmeier, w.f. & margat, j. (1995): hydrogeological maps. a guide and a standard legend.– international contribution to hydrogeology, 17, 77 p. iah. ver­ lag heinz heise, hannover, germany. wang, g. & yang, h. (2008): the report on hydrogeological survey of selected typical regions at 1:50.000.– the institute of hydrogeology and environmental geology, cags, shijiazhuang (in chinese). wen, d., wang, g., zhang, e. & yang, h. (2012): the specification for hydro­ geological survey 1:50.000 – trial version.– china geological survey, beijing (in chinese). wu, a., wang, g. & yang, h. (2015): the explanation on formulating specification for hydrogeological survey 1:50.000.– china geological survey, beijing (in chi­ nese). g eo lo gi a c ro at ic a geologia croatica 71/2112 2020 | 73/2 | 119–130 | 5 figs. | 1 tab. | 1 supp. tab. www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction stretching discontinuously for about 9500 km, from the european alps to southern tibet, the tethyan ophiolites structurally overlie passive margin successions of collided continents and commonly show fully developed ophiolitic sequences, which also include high-grade sub-ophiolite metamorphic rocks (dilek & furnes, 2019: fig. 8b, and references therein). the latter are present at the base of many tethyan ophiolite complexes, which formed at temperatures not exceeding 1200°c (e.g. guilmette et al., 2008; sarifakioǧlu et al., 2010; borojević sostarić et al., 2014; kakar et al., 2015; mulder et al., 2016; šegvić et al., 2016). sub-ophiolite or metamorphic soles are characteristic for subduction realms, more specifically for the zones of high temperatures and variable pressures, which exist below the upper plate’s hot sub-oceanic mantle (e.g. pamić et al., 2002; lázaro et al., 2013). soles emerge in the form of thin dismembered sheets and, therefore, outcrop only sporadically (e.g. pomonis et al., 2002), yet they are of great geotectonic importance as they adumbrate a shift in the regional dynamics of the oceanic floor (dilek & flower, 2003), which provides vital information on the evolution of the ocean as well as on the subsequent sm-nd geochronology and petrologic investigation of a sub-ophiolite metamorphic sole from the dinarides (krivaja-konjuh ophiolite complex, bosnia and herzegovina) branimir šegvić*1, damir slovenec2, ralf schuster3, elvir babajić4, luka badurina1 and †boško lugović5 1 texas tech university, department of geosciences, 1200 memorial circle, lubbock tx 79409, usa; (*corresponding author: branimir.segvic@ttu.edu; luka.badurina@ttu.edu) 2 croatian geological survey, department of geology, sachsova 2, 10000 zagreb, croatia; (dslovenec@hgi-cgs.hr) 3 geological survey of austria, neulinggasse 38, 1030 vienna, austria; (ralf.schuster@geologie.ac.at) 4 university of tuzla, faculty of mining, geology and civil engineering, univerzitetska 2, 75100 tuzla, bosnia and herzegovina; (elvir.babajic@untz.ba) 5 university of zagreb, faculty of mining, geology and petroleum engineering, perottijeva 6, 10000 zagreb, croatia doi: 10.4154/gc.2020.09 abstract the dinaridic segment of neotethys was affected by a widespread shortening and related subduction-accretion-obduction processes that commenced in the middle jurassic. in the dinarides, the krivaja-konjuh ophiolite complex (kkoc) stands as the largest ophiolite complex with a well-exposed metamorphic sole which is the key to understanding the dynamics of intraoceanic subduction initiation in this part of neotethys. in this contribution we present sm-nd geochronology on a granulite facies amphibolite from the kkoc, as well as a detailed petrological description. a five-point isochrone age calculated from clinopyroxene, plagioclase, garnet, amphibole and whole rock is 162 ± 14 ma (mswd = 6.2), whereas garnet and whole rock yield 160 ± 7 ma. ages calculated from all data points except clinopyroxene are 162 ± 5 ma (mswd = 1.09). petrographic investigations suggest that these ages date granulite facies metamorphic conditions (i.e. peak metamorphism of grt-cpx amphibolite) rather than post-peak exhumation or obduction processes. phase textural relationships are in line with previous research, which indicated a peak metamorphism equilibration pressure and temperature of ~1 gpa and ~800 °c, respectively. granulite facies conditions are elucidated for an igneous precursor, which underwent a multi-stage metamorphism that gave rise to recrystallization of igneous clinopyroxene and plagioclase, epitaxial growth of amphibole, and garnet blastosis. taking into account the age of gabbronorite from the youngest segment of the kkoc oceanic crust (taorcian to bathonian) and ages of radiolarian assemblages from the kkoc mélange (bajocian to bathonian), it may be inferred that within ~25 ma the dinaridic segment of neotethys evolved rapidly from active ridge spreading through a stage of intraoceanic subduction and arc magmatism toward sub-ophiolite exhumation and further obduction along the adria passive margin at the end of the jurassic era. ophiolite emplacement history (çelik & delaloye, 2006; parlak, 2016). the jurassic ophiolites of the dinarides form a narrow and elongated zone usually divided into two major regional belts the central dinaridic ophiolite belt (cdob) in the west and the vardar zone in the east (fig. 1). there are two schools of thought with respect to the origin of these belts. the first argues for a derivation of both ophiolite belts from the same marginal segment of neotethys, which ultimately led to the actual position of ophiolites within the dinarides-hellenides nappe stack (pamić et al., 1998; schmid et al., 2008; faul et al., 2014), while the second one favours the existence of two neotethyan oceanic branches (e.g. lugović et al., 1991; robertson, 2004), which were also defined in the hellenides (ferrière et al., 2012). both ophiolitic belts contain high-grade jurassic metamorphic rocks (e.g. majer & lugović, 1985; gjata et al., 1992; robertson & karamata, 1994; bébien et al., 2000; srećkovićbatoćanin et al., 2002; chiari et al., 2011). the focus of this study is the metamorphic sole rocks of the krivaja-konjuh ophiolite complex (kkoc), which is the biggest ultramafic exposure in the dinarides (fig. 1). amphibolite and granulite dominate the metamorphic suite of the kkoc (pamić et al., 1977; article history: manuscript received february 25, 2020 revised manuscript accepted june 02, 2020 available online june 30, 2020 keywords: dinarides, sm-nd ages, high-grade metamorphic sole, neotethys closure, jurassic ophiolites mailto:branimir.segvic@ttu.edu mailto:luka.badurina@ttu.edu mailto:dslovenec@hgi-cgs.hr mailto:ralf.schuster@geologie.ac.at mailto:elvir.babajic@untz.ba g eo lo gi a c ro at ic a geologia croatica 73/2120 operta et al., 2003). these rocks underwent high temperature metamorphism at variable intermediate pressures (šegvić, 2010). k-ar dating yielded ages in the range of 170 to 160 ma (lanphere et al., 1975), which correlate relatively well with the dating of radiolarian chert from the kkoc mélange, which was determined to be from late bajocian to early bathonian in age (šegvić et al., 2014). the research on orogenic belts has particularly benefited from sm-nd geochronology and related p-t-t studies as the former determines the timing of specific tectonic events during the evolution of metamorphic complexes and, therefore, of continental lithosphere (e.g. xu et al., 1994; thöni, 2002; plotnikov et al., 2003; cheng et al., 2011; dragovic et al., 2015; cheng, 2019; wang et al., 2019). in the high-grade metamorphic assemblage of the metamorphic sole garnet is a critical phase, because it enriches sm with respect to nd, giving the opportunity to measure ages with a precision better than 1% (e.g. mezger et al., 1992; dutch & hand, 2010; romer & rötzler, 2011; baxter et al., 2017). moreover, the closure temperature of the sm-nd system in garnet is high enough to define the age of the peak metamorphic assemblage instead of events during the cooling of the system. careful petrographic and figure 1. upper part: a geotectonic schematic map of se europe showing the mesozoic tethyan ophiolites stretching parallel to the dinarides. the rectangle indicates the position of the krivaja-konjuh ophiolite complex (study area). map modified after robertson (2002) and šegvić et al. (2019); lower part: a simplified geological map of the krivaja-konjuh ophiolite complex. modified after pamić (1968; 1970), đorđević and pamić (1972), and šegvić et al. (2019). the sw-ne cross-section a-b depicts the tectonic nature of the contact between large blocks of ultramafites and subordinate mafic rocks. g eologia c roatica šegvić et al.: sm-nd geochronology and petrologic investigation of a sub-ophiolite metamorphic sole from the dinarides ... 121 mineralogical considerations are however needed to address the difference. in this contribution we report a sm-nd isochron age combined with petrologic observations, which are used to constrain the p-t-t evolution of the metamorphic sole of the kkoc. several stages of the subduction-extrusion cycle are reconstructed based on metamorphic parageneses and their respective mineral reactions. details on the jurassic dynamic evolution in the dinarides are of broader regional significance as contemporaneous subduction processes took place in the albanides and hellednides (bortolotti et al., 2013; tremblay et al., 2015; kydonakis et al., 2016), while in the taurides, the subophiolitic sole is largely cretaceous in age (çelik & delaloye, 2006; elitok & drüppel, 2008; hässig et al., 2019). 2. geological setting in the dinarides a large number of ophiolite rocks occurs either in the form of small blocks (m to km in size) or as large thrust sheets, which may cover as much as 1000 km2 (e.g. trubelja et al., 1995; šuica et al., 2018). fragments of the ophiolite sequence are also present in a mélange (fig. 1; dimitrijević & dimitrijević, 1973; šegvić et al., 2014) consisting of a pelitic to silty sedimentary matrix which incorporated various igneous and sedimentary rocks during tectonic processes (pamić et al., 2002). such a mélange is present in the footwall of the ophiolite complexes in the dinarides (tari, 2002). the oceanic crust décollement was followed by the late jurassic obduction of oceanic crust onto adria’s passive margin (pamić et al., 1977; chiari et al., 2011), which largely explains the recent tectonic position of the dinaridic ophiolites. the kkoc is located in central bosnia and herzegovina and covers an area of about 650 km2 with a distinct nw-se elongation (fig. 1; pamić et al., 1977; pamić & hrvatović, 2003). the complex is divided into two large blocks, the western krivaja block, which represents an amalgamation of ultramafic and mafic rocks, while the eastern konjuh block largely consists of peridotite (fig. 1; pamić, 1968, 1970; đorđević & pamić, 1972). the ophiolite blocks are tectonically incorporated in a mélange which was thrust onto lower to middle jurassic sedimentary rocks of the adria continental margin and the whole sequence is overstepped by the cretaceous basinal pogari formation (pamić, 1970; hrvatović, 2006). the reporting of jurassic foraminifera such as vidalina martana, glomospira sp., cristellaria sp. (pamić & hrvatović, 2000) from micrite interlayered with shale and greywacke correlates well with the previously mentioned bajocian to bathonian age of the radiolarian chert, thus defining the late jurassic age of the mélange (šegvić et al., 2014). the kkoc ultramafics are mostly peridotite (~80%; pamić, 1968, 1970; đorđević & pamić, 1972) with some minor dunite and pyroxenite (pamić et al., 1977; maksimović & majer, 1981; lugović et al., 1991; trubelja et al., 1995). the mafic rocks are predominantly represented by gabbro (pamić et al., 1977; babajić, 2009). in addition to mafic and ultramafic rocks, an elongated zone composed of greenschist to granulite facies metabasaltic and metapelitic rocks occurs discontinuously at the base of the eastern peridotite block (pamić et al., 1977; operta et al., 2003). the contact of metamorphic rocks with the overlying peridotites is largely syn-metamorphic. conversely the contact with the mélange has hitherto not been documented (pamić et al., 2002; šegvić, 2010). at several locations within the complex a clear metamorphic zonation is reported with the granulite exposed adjacent to the peridotite, whereas the rocks of upper and lower amphibolite facies are found further away from the contact (pamić et al., 1977; šegvić, 2010). metamorphic conditions of the granulite facies rocks were estimated to be in the range of 850 to 1100 °c and from 1.1 to 1.3 gpa. the protoliths were most likely mafic cumulates formed in a supra-subduction zone setting and to a lesser extent morb-like mafic extrusives entrained in the subduction/thrusting system as a result of middle jurassic contraction of neotethys (šegvić et al., 2019). 3. materials and methods rocks were sampled from 11 locations dispersed throughout the kkoc. in most cases analyzed samples were taken from natural outcrops and only exceptionally, in the event of outcrop inaccessibility, were they gathered from nearby mountain streams. data on the phase chemistry discussed in this contribution represent a subset of microprobe data given in šegvić et al. (2019) and are provided here as supplementary material (supplementary material table 1). the metamorphic p-t space has been defined through the respective reaction curves calibrated in a basaltic system (ncfmash and cfmash) (fig. 5). reaction curves (1), (2), and (3) are from ernst and liu (1988), (4), (5), and (6) from green and ringwood (1967), (7), (8), and (9) from mukhopadhyay and bose (1994), (11) and (12) from liu et al. (1996) and (13) from frey et al. (1991). for dating by the sm-nd method, sample u22 derived from the prevailing kkoc metamorphic lithotype was carefully chosen to ensure mineral freshness. mechanical and chemical sample preparation was performed at the austrian geological survey, following the procedure described by sölva et al. (2005). for sm-nd isotopic analyses a whole rock powder and handpicked mineral separates of garnet, clinopyroxene, plagioclase and amphibole were used. the weights of material used for dissolution were 100 to 200 mg. overall blank contributions were < 200 pg for nd and sm. isotopic measurements were carried out at the university of vienna, austria. spiked sm and nd ratios were measured by a finnigan® mat 262, whereas unspiked nd and sr ratios were analyzed using a thermofinnigan® triton thermal ionisation mass spectrometer (tims). all elements were run from re double filaments. on the triton ti the la jolla standard yielded 143nd/144nd = 0.511844 ± 0.000001 (2σ) (n = 45) during the period of measurements. errors for the 147sm/144nd table 1. sm-nd isotopic data of sample u-22 from the krivaja-konjuh ophiolite complex material sm (ppm) nd (ppm) 147sm/144nd 143nd/144nda ±2sm whole rock 0.518 1.087 0.2878 0.513115 0.000003 pyroxene 0.648 1.432 0.2737 0.513090 0.000003 garnet 0.311 0.367 0.5119 0.513349 0.000007 plagioclase 1.683 3.716 0.2738 0.513101 0.000003 amphibole 2.042 5.274 0.2341 0.513056 0.000002 sm and nd concentrations were detected by isotope dilution. nd isotopic ratios are calculated from 650-800 valid runs at 1.7 to 5.0 v intensity. errors are given at the 2s-level. g eo lo gi a c ro at ic a geologia croatica 73/2122 figure 2. selected photomicrographs (crossed nicoles, (c), (d), (f ), (g); parallel nicoles, (a); and bse images, (b), (e), (h)) and analyzed rocks. for details see the text; amp-amphibole; cpxclinopyroxene; opxorthopyroxene; mtmagnetite; grtgarnet; plplagioclase; rtrutile. mineral abbreviations after kretz (1983). g eologia c roatica šegvić et al.: sm-nd geochronology and petrologic investigation of a sub-ophiolite metamorphic sole from the dinarides ... 123 ratio are ± 1% or smaller, determined based on iterative sample analysis and spike recalibration. ages were calculated with the isoplot/ex software (ludwig, 2003). 4. results 4.1. petrography the texture of high-grade metamorphic rocks of kkoc is granoblastic to porphyroblastic. the former is defined by coarse blasts of amphibole and plagioclase, whereas in the latter one reports on porphyblasts of garnet (up to 1 cm) merged in a fine-grained homogenous matrix. further rock subdivisions have been made based on their geochemistry (i.e. meta-cumulates vs. metabasalts; šegvić et al., 2019). accordingly, the sapphirine-bearing and corundum-bearing amphibolite, garnet-clinopyroxene (±orthopyroxene) amphibolite and amphibolite per se are classified as metacumulates, whereas clinopyroxene±garnet amphibolite and clinopyroxene-plagioclase±garnet gneiss represent metabasalts. more details on petrography of kkoc metamorphic rocks may be found in šegvić et al. (2019). here, further information is provided for garnet-clinopyroxene±orthopyroxene (grt-cpx±opx) amphibolite, which is the most common type of the kkoc metamorphic rocks and was therefore chosen for sm-nd dating. paragenesis of grt-cpx(±opx) amphibolite accounts for garnet, amphibole, clinopyroxene, and plagioclase. texturally equilibrated orthopyroxene may also emerge as a major paragenetic mineral, appearing in the form of pinkish crystalloblasts (fig. 2a). minor phases are ti-minerals such as rutile, titanite, and ilmenite as well as magnetite. subrounded porphyroblasts of garnet and lesser amounts of clinopyroxene and amphibole define a porphyroblastic texture (fig. 2b). garnet is pyrope to almandine (supplementary material table 1) and displays either a characteristic ushape of its pyrope component or no compositional zonation when equilibrated at peak metamorphic conditions (šegvić et al., 2019). it may contain embedded clinopyroxene, amphibole, plagioclase, rutile and titanite (fig. 2c). formation of kelyphitic coronas around some garnet blasts reflects the geochemical disequilibrium of the system after the metamorphic peak (fig. 2d). garnet retrograde decomposition gave rise to the formation of secondary ca-rich plagioclase, orthopyroxene and magnetite, while xonotlite, albite, epidote, pumpellyite and prehnite are reported only sporadically (fig. 2c). yet there are numerous grains of garnet, which document peak equilibrium with amphibole and plagioclase. amphibole’s composition spans from edenite to pargasite (supplementary material table 1; fig 7b in šegvić et al., 2019) and is texturally equilibrated with high-al diopside (supplementary material table 1; fig. 8b in šegvić et al., 2019). the latter may be found embedded in amphibole, which testifies to the igneous nature of the clinopyroxene (moazzen & oberhänsli, 2008). fine rims of amphibole and orthopyroxene may also be developed around larger crystalloblasts of clinopyroxene (fig. 2e). this textural feature along with ubiquitous garnet coronas is taken as a sign of incomplete re-equilibration of granulite facies assemblages during later overprints (e.g. groppo et al., 2015; šegvić et al., 2019). the an-rich plagioclase is commonly structured within the matrix while large blasts are rare and unrepresentative of plagioclase appearance (fig. 2a; fig 8b in šegvić et al., 2019). when present, the non-kelyphitic orthopyroxene is represented by pinkish pleochroitic crystalloblasts texturally equilibrated with amphibole and plagioclase (fig. 2a). it is primarily hypersthene with 68.2 to 78.6 wt% en (supplementary material table 1; šegvić et al., 2019). ti-rich phases, rutile and ilmenite, are also abundant in the analyzed amphibolite. 4.2. sm-nd geochronology sm-nd analyses were performed on clinopyroxene, plagioclase, garnet, amphibole and whole rock separates of sample u22 (table 1. and fig. 3). the whole rock, as well as the analyzed minerals are characterized by their low nd and sm contents (0.3-5.3 ppm) typical for basaltic rocks. for the whole rock an et nd(chur) value of 7.4 was calculated for t = 160 ma. the lowest 147sm/144nd ratio was measured in amphibole (0.2341), while the whole rock plots in between plagioclase and garnet that display the highest ratio (0.5119). an isochron age calculated from all five data points yields an age of 162 ± 14 ma (mswd = 6.2). the large error and mswd value are due to a limited spread in the 147sm/144nd ratios and clinopyroxene plotting below the regression line. ages calculated from all data points except clinopyroxene and from whole rock and garnet only are 162 ± 5 ma (mswd = 1.09) and 160 ± 7 ma, respectively. 5. discussion 5.1. p-t-t metamorphic evolution peak-metamorphic conditions of granulite facies can often be reset by diffusion, which is referred to in the literature as the ‘granulite uncertainty principle’ (harley, 1989). metamorphic rocks studied herein are suggested to have been formed by a short-time metamorphic overprint induced by the rapid subduction below a hot upper-plate and subsequent rapid cooling during ophiolite exhumation and obduction, thus preserving the peakmetamorphic assemblages intact. the orthopyroxene-free grtcpx amphibolite analyzed in this contribution is diagnostic for high-grade metamorphic assemblages potentially transitional to eclogite facies (e.g. mukhopadhyay & bose, 1994; pattison et al., 2003). the presence of garnet and rutile in metabasite indicates a minimum pressure of 0.8 to 1.0 gpa regardless of the temperature (ernst & liu, 1998). the appearance of clinopyroxene with no orthopyroxene at such pressures denotes a peak temperature in the range of 750 to 800 °c (guilmette et al., 2008). the amphibole-plagioclase geothermometers yielded equilibration temperatures for this rock type of between 725 to 950 °c. the garnet-clinopyroxene and garnet-amphibole fe-mg exchange thermometers also fit the suggested temperature figure 3. sm-nd isochron diagram of grt-cpx amphibolite (sample u-22) from the southern parts of the kkoc (duboštica area). the age and the related initial nd ratio is calculated from clinopyroxene, plagioclase, garnet, amphibole and whole rock. g eo lo gi a c ro at ic a geologia croatica 73/2124 values (šegvić et al., 2019). garnet-clinopyroxene-plagioclase geobarometers consistently show equilibration pressures of 0.94 to 1.30 gpa. if orthopyroxene is present, the pressure interval seems to be somewhat narrower ranging from 1.10 to 1.30 gpa (šegvić et al., 2019). we propose a multi-stage metamorphic history for grt-cpx amphibolite outlined by the trajectory in figure 5. the igneous protolith, comprising clinopyroxene and plagioclase, must have undergone a high-grade pressure-dominated amphibolite to granulite facies metamorphism reaching its peak with amphibole consumption (reaction 7 in fig. 4; mukhopadhyay & bose, 1994; bucher & frey, 2002). the course of prograde metamorphism is documented by pargasitic substitution in amphibole and is characteristic of the u-shape of the pyrope component in garnet (šegvić et al., 2019). the peak-metamorphic conditions did not last long enough to allow for the complete consumption of amphibole (minimal required temperature of >850 °c), nor any foreign fluid having a low ah2o entered the metamorphic system to enhance amphibole dehydration. the course of prograde metamorphism in the grt-cpx amphibolite was essentially multifold consisting of three stages: (1) recrystallization of igneous clinopyroxene and plagioclase, (2) epitaxial growth of pargasitic amphibole over clinopyroxene relicts (fig. 2e), and (3) garnet crystallization at high subto super-solidus temperatures (600-800 °c) by the reaction of amphibole and plagioclase that are regularly found as inclusions in garnet (fig. 2f; reaction 3 in fig. 4; wolf & wyllie, 1994). high temperatures of garnet crystallization allowed for the appearance of rutile needles (fig. 2g), which are normally formed as a response to induced strain in high-grade metabasalts when micro-scale partial melts react with garnet giving rise to the formation of the oriented rutile needles (e.g. hwang et al., 2007). high-grade metamorphic conditions inferred for grt-cpx amphibolite must have been achieved during the intraoceanic subduction of the dinaridic part of neotethys. thereupon, the peak metamorphic assemblages were altered at continued high temperatures, which led to the formation of well-preserved reaction textures around both garnet and clinopyroxene (figs. 3d,h; brandt et al., 2003; rao & chmielowski, 2011). for similar metamorphic complexes a mechanism was suggested that involves a reaction of garnet and clinopyroxene with silica, which leads to the formation of orthopyroxene along with plagioclase and magnetite (prakash et al., 2007; grt + cpx + silica → opx + pl + mt). bearing in mind that the analyzed metamorphic rocks are practically quartz-free, silica was likely mobilized by the breakdown of igneous clinopyroxene and its replacement by amphibole (~50 vs. ~40 wt% sio2). orthopyroxene from garnet coronas in grt-cpx(±opx) amphibolite is rich in al2o3 (up to 6.08 wt. %, šegvić et al., 2019), which testifies to the high-temperature conditions that prevailed during garnet decomposition (harley, 1989). furthermore, orthopyroxene rims around clinopyroxene (fig. 2e) are taken as diagnostic for further decompression accompanied by a temperature rise (~50 °c; mukhopadhyay & bose, 1994; tamashiro et al., 2004; seo et al., 2005). this event must have lasted only for a short time, but long enough to form the discrete orthopyroxene rims. an enhanced retrogression is also indicated by intergrowths of titanite and ilmenite (reaction 11 in fig. 4), which suggest a rapid cooling and decompression accompanied by hydration (harlov et al., 2006). the occurrences of xonotlite, albite, epidote, pumpellyite and prehnite at the expense of decomposing garnet can be linked to this late stage of metamorphism (hacker & mosenfelder, 1996; dubacq et al., 2019). based on this discussion, a prograde pressure dominated high-temperature metamorphism is suggested for the analyzed grt-cpx(±opx) amphibolite. this event was followed by decompression induced decomposition of the garnet and orthopyroxene formation during a short temperature rise at moderate pressure conditions. final cooling and decompression took place under greenschist facies conditions. in the grt-cpx(±opx) amphibolite where orthopyroxene emerges as a texturally equilibrated phase (fig. 2a), the heating event at moderate pressures likely lasted somewhat longer giving rise to the blastosis of orthopyroxene, which may contain inclusions of amphibole. this documents the last temperature rise in this metamorphic system (d’el-rey silva et al., 2007). 5.2. sm-nd geochronology the high-grade metamorphic assemblage consisting of fresh garnet, pyroxene and plagioclase was found suitable for dating by the sm-nd method and according to the literature this method is characterized by high closure temperatures (e.g. mezger et al., 1992; dutch & hand, 2010). with respect to garnet, varying values of more than 600 or even 800 °c are suggested for eclogite and granulite facies metabasalt at dry conditions and high cooling rates (jung and metzger, 2001; thöni, 2002). as the investigated rocks experienced temperatures of more than 800 °c and fast cooling, a sm-nd isochron defined by the major components will indicate crystallization of the metamorphic peak assemblage instead of later rejuvenations along the cooling path of the rocks. the age calculated from amphibole, plagioclase, clinopyroxene, garnet and the whole rock yielded 162 ± 14 ma (fig. 3). the large error is also expressed by the mean squared weighted deviation (mswd) of 6.2, which is a measure for the fit of the data points to the isochron line. as already mentioned in section 4.2., the error is mostly due to clinopyroxene plotting below the regression line, indicating a disequilibrium with respect to the other mineral phases. this disequilibrium might be explained by the petrographic investigations pointing to a partly preserved inherited igneous chemical composition of clinopyroxene (cf. section figure 4. hypothetical p-t path for grt-cpx amphibolite of kkoc. the drawing in the upper left corner depicts a supra-subduction setting in which the metamorphic sole formed. g eologia c roatica šegvić et al.: sm-nd geochronology and petrologic investigation of a sub-ophiolite metamorphic sole from the dinarides ... 125 4.1.). therefore, the isochron ages of 162 ± 5 ma (mswd = 1.09) calculated from whole rock, amphibole, plagioclase and garnet or 160 ± 7 ma determined from whole rock and garnet are more meaningful. in conclusion, a late middle to early late jurassic age of 160 ± 7 ma can be predicted for the crystallization of the peak-assemblage of the grt-cpx(±opx) amphibolite. the initial 143nd/144nd ratio is 0.512814 ± 0.000002, corresponding to an et nd(chur) value of 7.4. 5.3. implications for the geology of the dinarides field evidence and petrogenesis of the kkoc metamorphic rocks adumbrate their genetic link with the adjacent mafic and ultramafic rocks, which are the dominant lithologies of the complex (pamić et al., 1977; šegvić et al., 2019). this aids the definition of the studied metamorphic rocks as dismembered dynamothermal metamorphic soles formed in a supra-subduction system, where newly born lithosphere remains hot (e.g. robertson, 2004; saccani et al., 2011). in the dinarides the age of the metamorphic sole has thus far been positioned to the onset of the oxfordian (e.g. lanphere et al., 1975) which is supported by this study (mid-oxfordian; fig. 3). this complements well with the latest bajocian to early bathonian age of radiolarian assemblages obtained from the chert-rich shaly to silty matrix of the kkoc mélange (šegvić et al., 2014). taking into account the sm-nd age of gabbronorite from the youngest segment of the kkoc oceanic crust, which is set to the toarcian to bathonian time (babajić, 2009) we argue for a geodynamic evolution that ultimately resulted in intraoceanic subduction and closure of the major part of neotethys by the end of the jurassic. high-ti basalts with n-morb affinity derived from the tectonic lower plate as well as low-ti iat basalts from the upper plate (babajić, 2009; šegvić et al., 2019) were both entrained in the mélange of the subduction channel (fig. 5a). based on a hypothesized subduction angle (~30°) and an average subduction velocity of 5 cm per year (e.g. dewey, 1981) less than 10 ma is suggested from initiation of subduction till the down-going plate attained lithospheric depths of the wadati–benioff zone (flower et al., 2005). this emphasizes the time needed for a rapid transition of the geological setting in the dinaridic segment of neotethys from active ridge magmatism to intraoceanic subduction and related arc volcanism. it took further 5 to 7 ma for igneous lithologies to attain critical depths in the subduction zone and be metamorphosed at peak conditions of about 800 °c and 1 gpa during oxfordian time (figs. 6a-b). this is in line with the average duration of subduction cycles that last about 5 ma (murphy, 2006). the analyzed sole rocks must have been stripped off from the downgoing plate after the metamorphic peak was reached (fig. 5b). exhumed along the ancient subduction channel high-grade metamorphic rocks were thrust onto the adria margins along with the rest of the ophiolite sequence (pamić et al., 2002; robertson et al., 2009a; bortolotti et al., 2013; šegvić et al., 2016). the exhumation-obduction process was inferred to last between 10 to 15 ma as otherwise the upper plate would become too thick to obduct onto the continental margin and instead it would bulldoze the margin during the collision (šegvić et al., 2019). according to the scenario proposed herein the main branch of the dinaridic neotethys was closed by the end of the jurassic (fig. 5c). obducted ophiolites were partly incorporated in an early cretaceous over-stepping cycle by fluvial to shallow marine sediments of the pogari formation. in northern bosnia the latter figure 5. geodynamic model explaining the formation of the kkoc amphibolites adapted after šegvić et al. (2019). (a) the near-ridge subduction adumbrating the formation of an infant proto arc and aborted spreading centres in the marginal back-arc basin. sketch detail: intraoceanic subduction stage and formation of metamorphic sole and subsequent early exhumation of metamorphic sole relative to the ophiolite (adapted after wakabayashi and dilek (2000; 2003). (b) the late subduction stage and progressive accretionary emplacement. (c) the ophiolite and metamorphic sole obduction and final stage of oceanic closure. apaccretionary prism, babback-arc basin. g eo lo gi a c ro at ic a geologia croatica 73/2126 consists of conglomerate, sandstone, and some marly limestone (jovanović, 1961; hrvatović, 2006). the remaining backarc basins of the dinaridic segment of neotethys, characterized by local extension and back-arc magmatism, did not cease to exist by the end of the jurassic thus setting the final closure of neotethys in the barremian to aptian times (robertson et al., 2009b; slovenec & lugović, 2009; cvetković et al., 2014). the petrogenesis and the sm-nd age of the amphibolites from the krivaja-konjuh ophiolite complex correspond well to the models suggested for other metamorphic soles reported in the dinarides (karamata, 1968; trubelja et al., 1995) and the albanides-hellenides (gaggero et al., 2009; gartzos et al., 2009) thus advocating for similar ocean-floor dynamics for large parts of the westernmost neotethys, now present in the central and eastern mediterranean. 6. conclusions middle jurassic time was marked by the regional shortening of oceanic lithosphere of the dinaridic segment of neotethys which in turn caused complex subduction-accretion-obduction processes to occur. these developments were parental to the range of tethyan ophiolite complexes documented throughout the dinarides and beyond. the krivaja-konjuh ophiolite complex of central bosnia and herzegovina is the largest complex in the dinarides and is characterized by numerous exposures of well-preserved metamorphic sole rocks. welded to the upper peridotite plate during early subduction, the dating of the sole puts effective constraints on the onset of intraoceanic subduction. for the kkoc grt-cpx amphibolite, a five point sm-nd isochrone age was calculated from clinopyroxene, plagioclase, garnet, amphibole and whole rock corresponding to 162 ± 14 ma (mswd = 6.2), whereas garnet and whole rock yielded 160 ± 7 ma. petrological investigation of the dated amphibolite confirmed that these ages coincide with the peak metamorphism rather than reflecting an event that might have taken place during exhumation or obduction. peak pressures and temperatures are suggested to revolve around ~1 gpa and ~800 °c based on the related phase chemistry in textural equilibria. the mafic precursor of the analyzed amphibolite has undergone a multi-stage metamorphism which firstly led to the recrystallization of magmatic clinopyroxene and plagioclase followed by the growth of epitaxial amphibole and garnet blastosis. comparing the toarcian to bathonian age of gabbronorite from the youngest segment of the kkoc oceanic crust and the age of subduction onset in the dinaridic segment of neotethys, we propose less than ~25 ma were needed for the ocean floor rapid transformation from the ridge spreading through intraoceanic subduction to ophiolite obduction along adria’s margins at the end of the jurassic. acknowledgement this work has been supported by the croatian ministry of science, education and sport (grant no. 195-1951126-3205 to bl) and in part by the croatian science foundation under the project ip-2019-04-3824. we thank branka prša for her help with mineral separation. monika horschinegg is acknowledged for her assistance performing isotopic measurements. the first author is especially in debt to vesnica garašić, vladica cvetković, and ivan dragičević for fruitful scientific discussions at an early stage of the project. finally, constructive reviews by kristina šarić, ondrej nemec and one anonymous reviewer as well as the editorial handling and suggestions from dražen balen contributed significantly to the quality of the manuscript. references babajić, e. (2009): petrološko-geohemijska obilježja mafitnih stijena krivajskokonjuškog ofiolitnog kompleksa [petrological and geochemical characteristic of mafic rocks from the krivanja-konjuh ophiolitic complex – in bosnian, with an english abstract].– phd thesis, university of tuzla, 158 p. baxter, e., caddick, m. & dragović, b. (2017): garnet: a rock-forming mineral petrochronometer.– rev. mineral. geochem., 83, no. 1, 469–533. bébien, j., dimo-lahitte, a., vergély, p., insergueix-filippi, d. & dupeyrat, l. (2000): albanian ophiolites. i magmatic and metamorphic processes associated with the initiation of a subduction.– ofioliti, 25, 39–45. doi:10.4454/ ofioliti.v25i1.112 borojević šoštarić, s., palinkaš, a.l., neubauer, f., cvetković, v., bernroider, m. & genser, j. (2014): the origin and age of the metamorphic sole from the rogozna mts., western vardar belt: new evidence for the oneocean model for the balkan ophiolites.– lithos, 192–195, 39–55. doi:10.1016/j. lithos.2014.01.011 bortolotti, v., chiari, m., marroni, m., pandolfi, l., principi, g. & saccani, e. (2013): geodynamic evolution of ophiolites from albania and greece (dinaric-hellenic belt): one, two, or more oceanic basins?– int. j. earth sci., 102, 783–811. doi:10.1007/s00531-012-0835-7 brandt, s., klemd, r. & okrusch, m. (2003): ultrahigh-temperature metamorphism and multistage evolution of garnet–orthopyroxene granulites from the proterozoic epupa complex, nw namibia.– j. petrol., 44, 1121–1144. doi:10.1093/petrology/44.6.1121 bucher, k. & frey, m. (2002): petrogenesis of metamorphic rocks.– springer-verlag, berlin, heidelberg, 341 p. çelik, ö.f. & delaloye, m.f. (2006): characteristics of ophiolite-related metamorphic rocks in the beysehir ophiolitic mélange (central taurides, turkey), deduced from whole rock and mineral chemistry.– j. asian earth sci., 26, 461–476. doi:10.1016/j.jseaes.2004.10.008 cheng, h., zhang, c., vervoort, j.d., li, x., li, q., zheng, s. & cao, d. (2011): geochronology of the transition of eclogite to amphibolite facies metamorphism in the north qinling orogen of central china.– lithos, 125, 969–983. doi:10.1016/j.lithos.2011.05.010 cheng, h.a.o. (2019): garnet lu–hf and sm–nd geochronology: a time capsule of the metamorphic evolution of orogenic belts.– geol. soc. spec. pub., 474, 47–67. doi:10.1144/sp474.7 chiari, m., djerić, n., garfagnoli, f., hrvatović, h., krstić, m., levi, n., malasoma, a., marroni, m., menna, f., nirta, g., pandolfi, l., principi, g., saccani, e., stojadinović, u. & trivić, b. (2011): the geology of the zlatibor-maljen area (western serbia): a geotraverse across the ophiolites of the dinaric-hellenic collisional belt.– ofioliti, 36, 139–166. doi:10.4454/ofioliti.v36.i2.3 cvetković, v., šarić, k., grubić, a., cvijić, r. & milošević, a. (2014): the upper cretaceous ophiolite of north kozara-remnants of an anomalous midocean ridge segment of the neotethys.– geol. carpath., 65, 117–130. doi:10.2478/ geoca-2014-0008 d’el-rey silva, l.j.h., dantas, e.l., teixeira, j.b.g., laux, j.h. & da silva, m.d.g. (2007): u–pb and sm–nd geochronology of amphibolites from the curaçá belt, são francisco craton, brazil: tectonic implications.– gondwana res., 12, 454–467. doi:10.1016/j.gr.2006.11.008 dewey, j.f. (1981): episodicity, sequence and style at convergent plate boundaries.– in: the continental crust and its mineral deposits. geol. ass. can., spec. paper, 20, 553–572. dilek, y. & flower, m.f.j. (2003): arc-trench rollback and forearc accretion: 2. a model template for ophiolites in albania, cyprus, and oman.– geol. soc. spec. publ., 218, 43–68. doi:10.1144/gsl.sp.2003.218.01.04 dilek, y. & furnes, h. (2019): tethyan ophiolites and tethyan seaways.– j. geol. soc., 176, 899–912. doi:10.1144/jgs2019-129 dimitrijević, m.d. & dimitrijević, m.n. (1973): olistostrome mélange in the yugoslavian dinarides and late mesozoic plate tectonics.– j. geol., 81, 328–340. đorđević, d. & pamić, j. (1972): petrološki izvještaj za osnovnu geološku kartu, list vlasenica [basic geological map of sfry 1:100000, vlasenica sheet – in serbo-croatian].– federal geological survey, sarajevo, belgrade. dragovic, b., baxter, e.f. & caddick, m.j. (2015): pulsed dehydration and garnet growth during subduction revealed by zoned garnet geochronology and thermodynamic modeling, sifnos, greece.– earth planet. sci. lett., 413, 111–122. doi:10.1016/j.epsl.2014.12.024 dubacq, b., soret, m., jewison, e. & agard, p. (2019): early subduction dynamics recorded by the metamorphic sole of the mt. albert ophiolitic complex (gaspé, québec).– lithos, 334–335, 161–179. doi:10.1016/j.lithos.2019.03.019 dutch, r. & hand, m. (2010): retention of sm-nd isotopic ages in garnets subjected to high-grade thermal reworking: implications for diffusion rates of major and rare earth elements and the sm-nd closure temperature in garnet.– contrib. mineral. petrol., 159, 93–112. doi:10.1007/s00410-009-0418-1 g eologia c roatica šegvić et al.: sm-nd geochronology and petrologic investigation of a sub-ophiolite metamorphic sole from the dinarides ... 127 elitok, ö. & drüppel, k. (2008): geochemistry and tectonic significance of metamorphic sole rocks beneath the beyşehir-hoyran ophiolite (sw-turkey).– lithos, 100, 322–353. doi:10.1016/j.lithos.2007.06.022 ernst, w.g. & liu, j. (1998): experimental phase-equilibrium study of aland ticontents of calcic amphibole in morb; a semiquantitative thermobarometer.– am. mineral., 83, 952–969. doi:10.2138/am-1998-9-1004 faul, u.h., garapić, g. & lugović, b. (2014): subcontinental rift initiation and ocean-continent transitional setting of the dinarides and vardar zone: evidence from the krivaja–konjuh massif, bosnia and herzegovina.– lithos, 202–203, 283–299. doi:10.1016/j.lithos.2014.05.026 ferrière, j., chanier, f. & ditbanjong, p. (2012): the hellenic ophiolites: eastward or westward obduction of the maliac ocean, a discussion.– int. j. earth sci., 101, 1559–1580. doi:10.1007/s00531-012-0797-9 flower, r.m., bowring, s.a., tulloch, a.j. & klepeis, k.a. (2005): tempo of burial and exhumation within the deep roots of a magmatic arc, fiordland, new zealand.– geology, 33, 17–20. doi:10.1130/g21010.1 gaggero, l., marroni, m., pandolfi, l. & buzzi, l. (2009): modeling the oceanic lithosphere obduction: constraints from the metamorphic sole of mirdita ophiolites (northern albania).– ofioliti, 34, 17–42. doi:10.4454/ofioliti.v34i1.376 gartzos, e., dietrich, v.j., migiros, g., serelis, k. & lymperopoulou, t. (2009): the origin of amphibolites from metamorphic soles beneath the ultramafic ophiolites in evia and lesvos (greece) and their geotectonic implication.– lithos, 108, 224–242. doi:10.1016/j.lithos.2008.09.013 gjata, k., kornprobst, j., kodra, a., briot, d. & pineau, f. (1992): subduction chaude à l’aplomb d’une dorsale? exemple des enclaves de pyroxenite à grenat de la breche serpentineuse de derveni (albanie). [hot subduction close to ridge? examples of the garnet pyroxenite enclaves in the serpentinite breccia at derveni, albania in french, with an english abstract].– bull. soc. geol. fr., 163, 469–476. green, d.h., ringwood, a.e. (1967): the genesis of basaltic magmas.– contrib. mineral. petrol., 15, 103–190. groppo, c., rolfo, f., liu, y.-c., deng, l.-p. & wang, a.-d. (2015): p-t evolution of elusive uhp eclogites from the luotian dome (north dabie zone, china): how far can the thermodynamic modeling lead us?– lithos, 226, 183–200. doi:10.1016/j.lithos.2014.11.013 guilmette, c., hébert, r., dupuis, c., wang, c. & li, z. (2008): metamorphic history and geodynamic significance of high-grade metabasites from the ophiolitic mélange beneath the yarlung zangbo ophiolites, xigaze area, tibet.– j. asian earth sci., 32, 423–437. doi:10.1016/j.jseaes.2007.11.013 hacker, b.r. & mosenfelder, j.l. (1996): metamorphism and deformation along the emplacement thrust of the samail ophiolite, oman.– earth planet. sci. lett., 144, 435–451. doi:10.1016/s0012-821x(96)00186-0 harley, s.l. (1989): the origins of granulites: a metamorphic perspective.– geol. mag., 126, 215–247. doi:10.1017/s0016756800022330 harlov, d., tropper, p., seifert, w., nijland, t. & förster, h.-j. (2006): formation of al-rich titanite (catisio4o–caalsio4oh) reaction rims on ilmenite in metamorphic rocks as a function of fh2o and fo2.– lithos, 88, 72–84. doi:10.1016/j.lithos.2005.08.005 hässig, m., rolland, y., melis, r., sosson, m., galoyan, g. & bruguier, o. (2019): p-t-t history of the amasia and stepanavan sub-ophiolitic metamorphic units (nw armenia, lesser caucasus): implications for metamorphic sole development and for the obduction process.– ofioliti, 44, 43–70. doi:10.4454/ofioliti.v44i1.464 hrvatović, h. (2006): geološki vodič kroz bosnu i hercegovinu. [geological guide through bosnia and herzegovina in bosnian, with an english abstract].– geol. survey of federation of bosnia and herzegovina, ilidža (sarajevo), 203 p. hwang, s. l., yui, t. f., chu, h. t., shen, p., schertl, h. p., zhang, r. y. & liou, j. g. (2007): on the origin of oriented rutile needles in garnet from uhp eclogites.– j. metamorph. geol., 25, 349–362. doi:10.1111/j.1525-1314.2007.00699.x jovanović, r. (1961): prilog poznavanju prostranstva i facija mezozoika “unutrašnje zone dinarida” u nr bih [on the distribution of mesozoic facies of the internal dinarides in nr bih in serbo-croatian] – 3rd geological congress of yugoslavia, the union of geological societies of sfr yugoslavia, 148–176. jung, s. & mezger, k. (2001): geochronology in migmatites – a sm– nd, u–pb and rb–sr study from the proterozoic damara belt (namibia): implications for polyphase development of migmatisation in high-grade terranes.– j. metamorph. geol., 19, 77–97. doi: 10.1046/j.0263-4929.2000.00297.x kakar, m.i., mahmood, k., khan, m. & plavsa, d. (2015): petrology and geochemistry of amphibolites and greenschists from the metamorphic sole of the muslim bagh ophiolite (pakistan): implications for protolith and ophiolite emplacement.– arab. j. geosci., 8, 6105–6120. doi:10.1007/s12517-014-1613-6 karamata, s. (1968): zonality in contact metamorphic rocks around the ultramafic mass of brezovica (serbia, yugoslavia).– proceedings 23th international geological congress, 1, 197–207. kretz, r. (1983): symbols for rock-forming minerals.– am. mineral., 68, no. 1-2, 277–279. kydonakis, k., brun, j.-p., poujol, m., monié, p. & chatzitheodoridis, e. (2016): inferences on the mesozoic evolution of the north aegean from the isotopic record of the chalkidiki block.– tectonophysics, 682, 65–84. doi:10.1016/j. tecto.2016.06.006 lanphere, m.a., coleman, r.g., karamata, s. & pamić, j. (1975): age of amphibolites associated with alpine peridotites in the dinaride ophiolite zone, yugoslavia.– earth planet. sci. lett., 26, 271–276. doi:10.1016/0012821x(75)90001-1 lázaro, c., blanco-quintero, i.f., rojas-agramonte, y., proenza, j.a., núñez-cambra, k. & garcía-casco, a. (2013): first description of a metamorphic sole related to ophiolite obduction in the northern caribbean: geochemistry and petrology of the güira de jauco amphibolite complex (eastern cuba) and tectonic implications.– lithos, 179, 193–210. doi:10.1016/j.lithos.2013.08.019 liu, j., bohlen, s.r., ernst, w.g. (1996): stability of hydrous phases in subducting oceanic crust.– earth planet. sci. lett., 143, 161–171. ludwig, k.r. (2003): isoplot 3.00: a geochronological toolkit for microsoft excel.– berkeley geochronology center special publication, 4, 70 p. lugović, b., altherr, r., raczek, i., hofmann, a.w. & majer, v. (1991): geochemistry of peridotites and mafic igneous rocks from the central dinaric ophiolite belt, yugoslavia.– contrib. mineral. petrol., 106, 201–216. doi:10.1007/ bf00306434 majer, v. & lugović, b. (1985): metamorphic rocks from the ophiolite zone in banija, yugoslavia: amphibolites.– acta geologica zagreb, 15, 1–25. maksimović, z. & majer, v. (1981): accessory spinels of two main zones of alpine ultramafic rocks in yugoslavia.– bulletin de l’académie serbe des sciences et des arts, 21, 13–26. mezger, k., essene, e.j. & halliday, a.n. (1992): closure temperatures of the sm-nd system in metamorphic garnets.– earth planet. sci. lett., 113, 397–409. doi:10.1016/0012-821x(92)90141-h moazzen, m. & oberhänsli, r. (2008): whole rock and relict igneous clinopyroxene geochemistry of ophiolite-related amphibolites from nw iran implications for protolith nature.– neus jb. miner. abh., 185, 51–62. doi:10.1127/00777757/2008/0106 mukhopadhyay, b. & bose, m.k. (1994): transitional granulite-eclogite facies metamorphism of basic supracrustal rocks in a shear zone complex in the precambrian shield of south india.– mineral. mag., 58, 97–118. mulder, j.a., berry, r.f., meffre, s. & halpin, j.a. (2016): the metamorphic sole of the western tasmanian ophiolite: new insights into the cambrian tectonic setting of the gondwana pacific margin.– gondwana res., 38, 351–369. doi:10.1016/j.gr.2015.12.010 murphy, j.b. (2006): igneous rock associations 7. arc magmatism i: relationship between subduction and magma genesis.– geosci. can., 33, 145–167. operta, m., pamić, j., balen, d. & tropper, p. (2003): corundum-bearing amphibolites from the metamorphic basement of the krivaja-konjuh ultramafic massif (dinaride ophiolite zone, bosnia).– mineral. petrol., 77, 287–295. doi:10.1007/ s007100300002 pamić, j. (1968): petrološki izvještaj za tumač lista zavidovići, osnovne geološke karte sfrj [basic geological map of sfry 1:100000, zavidovići sheet – in serbocroatian].– federal geological survey, sarajevo, belgrade. pamić, j. (1970): petrološki izvještaj za tumač lista vareš, osnovne geološke karte sfrj [basic geological map of sfry 1:100000, vareš sheet – in serbo-croatian].– federal geological survey, sarajevo, belgrade. pamić, j., gušić, i. & jelaska, v. (1998): geodynamic evolution of the central dinarides.– tectonophysics, 297, 251–268. doi:10.1016/s0040-1951(98)00171-1 pamić, j. & hrvatović, h. (2000): dinaride ophiolite zone (doz). basic data on the geology and petrology of the krivaja-konjuh ophiolite complex. pancardi 2000 fieldtrip guidebook.– vijesti hrvatskoga geološkog društva, 37, 60–68. pamić, j. & hrvatović, h. (2003): main large thrust structures in the dinarides – a proposal for their classification.– nafta, 54, 443–464. pamić, j., sunarić-pamić, o., olujić, j. & antić, r. (1977): petrografija i petrologija krivajsko-konjuškog ofiolitskog kompleksa i njegove osnovne geološke karakteristike: geology, petrography, and petrology of the krivaja-konjuh ophiolite complex in the central part of the dinarides, yugoslavia.– acta geologica zagreb, 9, 59–135. pamić, j., tomljenović, b. & balen, d. (2002): geodynamic and petrogenetic evolution of alpine ophiolites from the central and nw dinarides: an overview.– lithos, 65, 113–142. doi:10.1016/s0024-4937(02)00162-7 parlak, o. (2016): the tauride ophiolites of anatolia (turkey): a review.– j. earth sci., 27, 901–934. doi:10.1007/s12583-016-0679-3 pattison, d.r.m., chacko, t., farquhar, j. & mcfarlane, c.r.m. (2003): temperatures of granulite-facies metamorphism: constraints from experimental phase equilibria and thermobarometry corrected for retrograde exchange.– j. petrol., 44, 867–900. doi:10.1093/petrology/44.5.867 plotnikov, a.v., kruk, n.n., vladimirov, a.g., kovach, v.p., zhuravlev, d. z. & moroz, e.n. (2003): sm-nd isotope systematics of metamorphic rocks in the western altai-sayan fold belt.– dokl. earth sci., 388, 63–67. g eo lo gi a c ro at ic a geologia croatica 73/2128 pomonis, p., tsikouras, b. & hatzipanagiotou, k. (2002): origin, evolution and radiometric dating of subophiolitic metamorphic rocks from the koziakas ophiolite (w. thessaly, greece).– neus jb. miner. abh., 177, 255–276. doi:10.1127/0077-7757/2002/0177-0255 prakash, d., arima, m. & mohan, a. (2007): ultrahigh-temperature mafic granulites from panrimalai, south india: constraints from phase equilibria and thermobarometry.– j. asian earth sci., 29, 41–61. doi:10.1016/j.jseaes.2006.01.002 rao, c.v.d. & chmielowski, r.m. (2011): new constraints on the metamorphic evolution of the eastern ghats belt, india, based on relict composite inclusions in garnet from ultrahigh-temperature sapphirine granulites.– geol. j., 46, 240–262. doi:10.1002/gj.1251 robertson, a.h.f. & karamata, s. (1994): the role of subduction-accretion processes in the tectonic evolution of the mesozoic tethys in serbia.– tectonophysics, 234, 73–94. doi:10.1016/0040-1951(94)90205-4 robertson, a. (2002): overview of the genesis and emplacement of mesozoic ophiolites in the eastern mediterranean tethyan region. lithos, 65, 1–67. https://doi. org/10.1016/s0024-4937(02)00160-3 robertson, a. (2004): development of concepts concerning the genesis and emplacement of tethyan ophiolites in the eastern mediterranean and oman regions.– earth-sci. rev., 66, 331–387. doi:10.1016/j.earscirev.2004.01.005 robertson, a., karamata, s. & šarić, k. (2009a): overview of ophiolites and related units in the late palaeozoic–early cenozoic magmatic and tectonic development of tethys in the northern part of the balkan region.– lithos, 108, 1–36. doi:10.1016/j.lithos.2008.09.007 robertson, a.h.f., karamata, s. & šarić, k. (2009b): ophiolites and related geology of the balkan region.– lithos, 108, vii-x. doi:10.1016/j.lithos.2008.10.013 romer, r.l. & rötzler, j. (2011): the role of element distribution for the isotopic dating of metamorphic minerals.– eur. j. mineral., 23, 17–33. doi:10.1127/09351221/2011/0023-2081 saccani, e., beccaluva, l., photiades, a. & zeda, o. (2011): petrogenesis and tectono-magmatic significance of basalts and mantle peridotites from the albanian–greek ophiolites and sub-ophiolitic mélanges. new constraints for the triassic–jurassic evolution of the neo-tethys in the dinaride sector.– lithos, 124, 227–242. doi:10.1016/j.lithos.2010.10.009 sarifakioǧlu, e., özen, h., çolakoǧlu, a. & sayak, h. (2010): petrology, mineral chemistry, and tectonomagmatic evolution of late cretaceous suprasubduction-zone ophiolites in the izmir-ankara-erzincan suture zone, turkey.– int. geol. rev., 52, 187–222. doi:10.1080/00206810902818479 schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpinecarpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss j. geosci., 101, 139–183. doi:10.1007/s00015-008-1247-3 šegvić, b. (2010): petrologic and geochemical characteristics of the krivaja-konjuh ophiolite complex (ne bosnia and herzegovina) petrogenesis and regional geodynamic implications.– phd thesis, university of heidelberg, heidelberg, 310 p. šegvić, b., kukoč, d., dragičević, i., vranjković, a., brčić, v., goričan, š., babajić, e. & hrvatović, h. (2014): new record of middle jurassic radiolarians and evidence of neotethyan dynamics documented in a mélange from the central dinaridic ophiolite belt (cdob, ne bosnia and herzegovina).– ofioliti, 39, 33–43. doi:10.4454/ofioliti.v39i1.427 šegvić, b., lugović, b., slovenec, d. & meyer, h.-p. (2016): mineralogy, petrology and geochemistry of amphibolites from the kalnik mt. (sava unit, north croatia): implications for the evolution of north-westernmost part of the dinaricvardar branch of mesozoic tethys.– ofioliti, 41, 35–58. doi:10.4454/ofioliti. v41i1.441 šegvić, b., slovenec, d., altherr, r., babajić, e., mählmann, r.f. & lugović, b. (2019): petrogenesis of high-grade metamorphic soles from the central dinaric ophiolite belt and their significance for the neotethyan evolution in the dinarides.– ofioliti, 44, 1–30. doi:10.4454/ofioliti.v44i1.462 seo, j., choi, s. g., oh, c. w., kim, s. w. & song, s. h. (2005): genetic implications of two different ultramafic rocks from hongseong area in the southwestern gyeonggi massif, south korea.– gondwana res., 8, 539–552. doi:10.1016/ s1342-937x(05)71154-0 slovenec, d. & lugović, b. (2009): geochemistry and tectono-magmatic affinity of mafic extrusive and dyke rocks from the ophiolite mélange of the sw zagorje-mid-transdanubian zone (mt. medvednica, croatia).– ofioliti; 34, 63–80. doi:10.4454/ofioliti.v34i1.378 sölva, h., grasemann, b., thöni, m., thiede, r. & habler, g. (2005): the schneeberg normal fault zone: normal faulting associated with cretaceous se-directed extrusion in the eastern alps (italy/austria).– tectonophysics, 401, 143–166. doi:10.1016/j.tecto.2005.02.005 srećković-batoćanin, d., milovanović, d. & balogh, k. (2002): petrolo gy of the garnet amphibolites from the tejići village – povlen mt., western serbia.– geološki anali balkanskog poluostrva, 64, 187–198. šuica, s., lugović, b. & kukoč, d. (2018): tectono-magmatic significance of the pillow basalts from the ophiolitic mélange of the dinarides.– ofioliti, 43, 85– 101. doi:10.4454/ofioliti.v43i1.506 tamashiro, i., santosh, m., sajeev, k., morimoto, t. & tsunogae, t. (2004): multistage orthopyroxene formation in ultrahigh-temperature granulites of ganguvarpatti, southern india: implications for complex metamorphic evolution during gondwana assembly.– j. mineral. petrol. sci., 99, 279–297. doi:10.2465/jmps.99.279 tari, v. (2002): evolution of the northern and western dinarides: a tectonostratigraphic approach.– egu stephan mueller special publication series, 1, 223–236. thöni, m. (2002): sm-nd isotope systematics in garnet from different lithologies (eastern alps): age results, and an evaluation of potential problems for garnet sm-nd chronometry.– chem. geol., 185, 255–281. doi: 10.1016/s0009-2541(01)00410-7 tremblay, a., meshi, a., deschamps, t., goulet, f. & goulet, n. (2015): the vardar zone as a suture for the mirdita ophiolites, albania: constraints from the structural analysis of the korabi-pelagonia zone.– tectonics, 34, 352–375. doi:10.1002/2014tc003807 trubelja, f., marchig, v., burgath, k.p. & vujović, ž. (1995): origin of the jurassic tethyan ophiolites in bosnia: a geochemical approach to tectonic setting.– geol. croat, 48, 49–66. wakabayashi, j. & dilek, y. (2000): spatial and temporal relationships between ophiolites and their metamorphic soles: a test of models of forearc ophiolite genesis.– geol. s. am. s., 349, 53–64. wakabayashi, j. & dilek, y. (2003): what constitutes ‘emplacement’ of an ophiolite?: mechanisms and relationship to subduction initiation and formation of metamorphic soles.– geol. soc. spec. publ., 218, 427–447. doi:10.1144/gsl. sp.2003.218.01.22 wang, d., vervoort, j.d., fisher, c.m., cao, h. & li, g. (2019): integrated garnet and zircon-titanite geochronology constrains the evolution of ultra-high– pressure terranes: an example from the sulu orogen.– j. metamorph. geol., 37, 611–631. doi:10.1111/jmg.12477 wolf, m.b. & wyllie, p.j. (1994): dehydration-melting of amphibolite at 10 kbar: the effects of temperature and time.– contrib. mineral. petrol., 115, 369–383. doi:10.1007/bf00320972 xu, b., chen, b., zhang, c., bai, z., wang, h. & zhang, q. (1994): sm-nd isochron and significance of the wuhuaoubao block in northern margin of sinokorean plate.– sci. geol. sin., 29, 168–172. g eologia c roatica šegvić et al.: sm-nd geochronology and petrologic investigation of a sub-ophiolite metamorphic sole from the dinarides ... 129 su pp le m en ta ry m at er al – t ab le 1 . su pp le m en ta ry m at er ia l t ab le  1 . s el ec te d el ec tr on m ic ro pr ob e an al ys es (i n w t% ) o f a m ph ib ol e, g ar ne t, an d pl ag io cl as e fe ld sp ar fr om k ko c so le s a nd re sp ec tiv e st ru ct ur al fo rm ul as . ro ck v ar ie ty m g m g m g m g m g m g m b m g m g m g m g m g m g m g sa m pl e cc 1 u 22 g r7 v1 v4 v1 z 1c cc 1 v1 u 40 v4 m k2 v1 u 40 n o. a na l. 13 13 28 10 2 28 87 49 70 60 16 22 47 10 1 64 m in er al a m a m g rt g rt (k el .ri m ) g rt p l ( in g rt ) pl cp x c px (i n a m ) cp x cp x o px (c px .r) o px (k .ri m ) o px (k .ri m ) si o 2 44 .4 2 40 .7 6 40 .6 4 37 .0 9 40 .7 9 50 .5 3 58 .9 4 52 .4 3 51 .4 7 50 .7 3 53 .6 1 53 .7 5 51 .3 6 50 .5 7 ti o 2 0 .7 7 0. 09 0. 03 0. 03 0. 03 0. 41 0. 10 0. 37 0. 05 0. 11 0. 00 0. 05 a l2 o 3 11 .4 2 16 .7 6 21 .7 7 21 .4 0 22 .7 0 31 .4 9 26 .2 4 9. 03 3. 15 4. 14 1. 56 2. 13 5. 21 6. 08 cr 2o 3 0. 10 0. 20 0. 12 0. 20 0. 15 0. 07 0. 03 0. 03 0. 04 0. 07 0. 01 4 0. 18 fe 2o 3 0. 89 9 17 .2 8 0. 00 0. 32 0. 30 fe o 12 .2 7 9. 98 13 .1 7 0. 90 15 .7 2 4. 91 6. 53 7. 34 5. 09 15 .5 0 14 .7 3 16 .3 0 m no 0. 17 0. 36 0. 14 1. 20 0. 79 0. 1 0. 17 0. 26 0. 23 1. 47 1. 26 0. 79 m go 13 .7 4 14 .7 6 13 .8 7 22 .5 8 13 .5 1 11 .0 7 14 .8 4 13 .9 1 16 .0 2 26 .7 1 26 .4 8 25 .4 4 ca o 11 .2 1 11 .2 7 8. 26 0. 19 6. 26 13 .9 4 7. 42 19 .4 3 21 .5 8 22 .4 5 23 .3 0 0. 69 0. 29 0. 33 n a2 o 2. 08 3. 33 0. 00 0. 19 3. 71 7. 62 2. 21 0. 50 0. 59 0. 35 0. 00 0. 00 0. 01 k2 o 0. 06 0. 01 0. 02 0. 00 0. 00 0. 01 0. 04 0. 04 0. 00 0. 00 0. 00 0. 00 0. 00 0. 01 h 2o 3. 76 2. 49 to ta l 96 .2 4 97 .5 1 99 .0 0 10 0. 87 99 .9 7 10 0. 01 10 0. 56 99 .7 0 98 .3 7 99 .8 2 10 0. 26 10 0. 42 99 .3 4 99 .7 5 si 6. 60 5. 91 3. 02 2. 62 3. 01 2. 30 2. 62 1. 90 1. 92 1. 88 1. 96 1. 93 1. 86 1. 83 ti 0. 09 0. 01 0. 00 0. 00 0. 00 0. 01 0. 00 0. 01 0. 00 0. 00 0. 00 0. 00 a l 1. 99 2. 86 1. 90 1. 78 1. 98 11 .6 9 1. 38 0. 38 0. 14 0. 18 0. 07 0. 09 0. 22 0. 26 cr 0. 01 0. 02 0. 00 0. 01 0. 01 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 01 fe 3+ 0. 08 0. 34 0. 05 0. 97 0. 00 0. 01 0. 01 0. 00 0. 05 0. 09 0. 04 0. 03 0. 07 0. 07 fe 2+ 1. 43 0. 87 0. 82 0. 05 0. 97 0. 15 0. 16 0. 14 0. 12 0. 43 0. 38 0. 42 m n 0. 02 0. 04 0. 01 0. 07 0. 05 0. 00 0. 01 0. 01 0. 01 0. 05 0. 04 0. 02 m g 3. 03 3. 19 1. 53 2. 48 1. 49 0. 60 0. 83 0. 77 0. 87 1. 43 1. 43 1. 37 ca 1. 78 1. 75 0. 66 0. 01 0. 50 0. 68 0. 35 0. 76 0. 86 0. 89 0. 91 0. 03 0. 01 0. 01 n a 0. 60 0. 94 0. 00 0. 00 0. 00 0. 33 0. 66 0. 16 0. 04 0. 04 0. 03 0. 00 0. 00 0. 00 k 0. 01 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 o h 2. 00 2. 00 m g# 67 .8 78 .5 63 .8 7 70 .7 8 60 .5 0 m g# 80 .1 84 .0 84 .7 88 .0 76 .8 79 .0 76 .6 py 50 .8 2 94 .7 1 49 .5 3 w o 50 .1 45 .5 47 .0 46 .8 1. 3 0. 6 0. 7 g r 18 .7 2 0. 00 16 .0 0 en 39 .8 43 .5 40 .5 44 .8 72 .7 74 .2 72 .1 a n 67 .4 34 .9 fs 10 .1 11 .0 12 .4 8. 3 25 .9 25 .2 27 .2 ch em ic al a na ly se s o f m os t m in er al s p er fo rm ed w ith fo cu se d el ec tr on b ea m o f a pp ro x. 1 µ m ra di i. fe ld sp ar m ea su re d by e le ct ro n be am o f 1 0 µm . f e an al ys ed a s f eo to ta l a nd e st im at ed a s fe 2+ a nd f e3+ o n fix ed n um be r o f 8 c at io ns /1 2 ox yg en s f or g ar ne t a nd 1 5 ca tio ns /2 3 ox yg en s f or a m ph ib ol e. f or m ul as o f p la gi oc la se c al cu la te d on th e ba si s o f 8 o xy ge ns , f eo to ta l is e xp re ss ed a s f e 2 o 3. fe a na ly se d as f eo to ta l a nd e st im at ed a s f e2+ a nd f e3+ o n fix ed n um be r o f 4 c at io ns /6 o xy ge ns fo r p yr ox en e. m in er al a bb re vi at io n (k re tz , 1 98 3) : a m = a m ph ib ol e, g rt = g ar ne t, pl = p la gi oc la se , k el .ri m = k el yp hi tic ri m , c px = c lin op yr ox en e, o px = o rt ho py ro xe ne . w o = w ol la st on ite , e n = en st at ite , f s = fe rr os ili te , p y = py ro pe , g r = g ro ss ul ar e, a n = an or th ite (a ll in % ), m g# =m g/ (m g+ fe 2+ ), m t – m et atr oc to lit e; m g – m et ag ab br o; m b – m et ab as al ts . g eo lo gi a c ro at ic a geologia croatica 73/2130  geologia croatica 68/3 173–178 1 fig. 2 pls. zagreb 2015 montenegrella? gracilis n. sp., a new calcareous alga (dasycladales) from the upper barremian of mt. biokovo (dinarides mts., croatia)  branko sokač and tonći grgasović croatian geological survey, sachsova 2, zagreb, croatia; (tgrgasovic@hgi-cgs.hr) doi: 10.4154/gc.2015.14 geologia croaticageologia croatica abstract montegrella? gracilis n.sp. (dasycladales) is characterized by a thick calcareous envelope and narrow central cavity. branches display two orders of laterals with alternate arrangement between consecutive whorls. the primaries are visibly differentiated into a thin, tendril-like stalk in the proximal part and a club-shaped or ellipsoidal inflated swelling in the distal part. the secondaries are poorly visible, of unclear shape and number, with a supposedly common starting point. in the type-locality, the alga occurs within a rich, typically upper barremian, algal assemblage. the validity of the genus montenegrella, being disputed by barattolo (1983), is commented upon by showing the generic attribution of the same or different species either to suppiluliumaella or to montenegrella by different authors. keywords: calcareous algae (dasycladales), taxonomy, barremian, dinarides mts., croatia 1. introduction while re-reviewing thin-sections made from sample kj-18 from barremian deposits of mt. biokovo we noticed sections of some dasycladalean algae that were not mentioned in previously published papers. the description and illustrations of these previously identified algae, accompanied by short descriptions of lithology, lithofacies changes, and the stratigraphic position of the sample kj-18 in the local geological column, were given in sokač (2004, 2005, 2007) and sokač & grgasović (2004, partly 2008). in addition, the outcrop in question was visited and discussed by the participants of the 9th international congress on fossil algae, held in 2007 in croatia. data given in the afore-mentioned publications will not be repeated here. the new species has been questioningly ascribed to montenegrella, in spite of the validity of that genus being disputed. barattolo (1983), in the description of his new species suppiluliumaella schroederi, compared morphological characteristics of the species ascribed hitherto to suppiluliumaella and montenegrella and concluded, that morphological details mentioned in the generic description of montenegrella sokač & nikler (1973) were not sufficient for the erection of the new genus, which, should, therefore, be considered a younger synonym of suppiluliumaella. consequently, barattolo (1983) suggested the transfer of all species described as montenegrella by sokač & nikler (1973), except perhaps m. fusiformis, as well as those described by dragastan (1978; m. transdanubica and m. alimani), to suppilulliumaella. he accepts the possible identity of montenegrella verae and m. tubifera, according to bassoullet et al. (1978). bernier (1978) thinks that m. florifera is inadequately known to be ascribed to suppiluliumaella, whereas m. corbarica jaffrezo (1975) could be ascribed to some other genus. later authors also espoused different views. some authors follow (or partly follow) barattolo’s (1983) opinion, whereas other continue to use montenegrella in their identifications. thus dragastan (1989) transfers his species m. transdanubica and m. alimani (dragastan, 1978) without any comment to suppiluliumaella, adding simultaneously two new species (s.leini and s. riedeli). these, however, are represented by insufficiently clear illustrations, which make their generic attribution questionable. similarly, there is no correct explanation for their inclusion in the synonymy of salpingoporella pygmaea, as has been done by carras et al. (2006). granier & deloffre (1993), in their inventory of jurassic and cretaceous fossil dasycladales, omit any critical analysis of the relationship between suppiluliumaella elliott 1968, and montenegrella sokač & nikler, geologia croatica 68/3geologia croatica 174 1978, the latter being invalidly described (no holotype was designated for its type-species). in this paper lectotypes are selected by the authors, thus giving montenegrella and the species described on this occasion a valid status. in contrast to barattolo (1983), carras (1995) accepted the originally described montenegrella corbarica jafrezzo (1975) as a valid species, but transferred it to suppiluliumaella, with one illustration (pl. 45, fig. 2) labelled s. corbarica (jaffrezo). bucur (2001), in the chapter on the lower cretaceous, (p. 68), mentions suppiluliumaella (montenegrella) tubifera and in the same publication, on p. 142 (stop 6), mentions and illustrates (pl. 8, figs 7-8; pl. 9) montenegrella tubifera sokač & nikler as the dominant species in the algal association. bucur & săsărăn (2005), in their description of the upper jurassic and lower cretaceous deposits of the trascău mountains, mention and illustrate (p. 28, pl. 1, fig. 11), among others, montenegrella cf. florifera bernier; that is, they accept both the genus montenegrella and the species m. florifera. in michetiuc, catincut & bucur (2008), the type-species of montenegrella (m. tubifera) is mentioned and illustrated (p.220, pl. vi, fig. 2) as suppiluliumaella tubifera. schlagintweit et al. (2006) give a picture (fig. 3/16) of an alga that is neither mentioned in the list of fossils nor in the list of sections pictured in fig. 3. however, an identical section is figured in gawlick et al. (2008, fig. 5/7) under the original name montenegrella tubifera sokač & nikler. comments above show that there reigns a bewildering confusion regarding the attribution of individual species to one genus or another of suppiluliumaella and montenegrella. the usage of the two generic denominations by individual or even the same authors on different occasions, for the same or different species originally attributed to montenegrella, shows the author’s dilemmas, resulting in inconsistent generic attributions. this question can be viewed (and explained) from different perspectives, but the opinion here is that the main reason seems to be the lack of clearly defined criteria, summing up variously validated biologic parameters, in a sufficient and unambiguously applicable manner in order to establish a new taxon (genus or species). such criteria should be accompanied by photomicrographs of three, four or more clear and unequivocal characteristic sections. unfortunately, the establishing of new taxa is frequently based upon one or two, (seldom more), poorly preserved, often heavily recrystallized sections that do not permit the insight into real and robust morphological characteristics. the establishment of new taxa based on such inadequate sections, adjusted to the author’s goals and personal opinion, makes the validity of a newly described taxon questionable, opening, at the same time, possibilities for further new combinations (and speculation). a description need not restrain the author’s freedom of expression: the authors are free to write up, line up and follow their own ideas, but the facts should be the same and equally visible for everybody, without personal, supposed conclusions, being either described or shown graphically, and aimed at supporting the author’s interpretation. the consequences of such inadequate and variable ranking of individual morphological parameters (e.g., can a bigger or smaller d and d in relation to an original description be a decisive criterion for separating species and, if so, which will be the limiting values?), may (unjustifiably) encourage various authors to establish and/or transfer taxa according to somebody’s personal opinion, without providing new data. following the aforementioned lack of critical analysis, and accepting only the last published opinion (which is often the case), opens a number of questions regarding the validity of individual species and their generic attribution. examples abound, but we don’t want to single out any particular example (each having an author) or to exempt ourselves. we are not convinced that these questions can be objectively treated by partial corrections on a case-by-case basis, with uncoordinated criteria,; instead, they can only deepen the existing confusion. the difference between the genera suppiluliumaella and montenegrella is clearly visible in the growth of secondary branches. in suppiluliumaella secondaries grow out of the entire surface of the distal end of the primary branch in the form of finger-like protrusions, but in montenegrella secondaries grow out as a bunch or a bundle of branches (see comparison drawings in sokač & nikler, 1973, tab. i). this is completely clear when the original material of the type species of both genera are compared (elliott, 1968, pl. 95, fig. 1-3; sokač & nikler, 1973, pl. 2, fig. 1-4, pl. 3, fig. 1, 3). therefore we retain the genus montenegrella to which we assign the new species, montenegrella? gracilis n. sp. however, because of the unclear shape of the secondaries and their relationships with the distal ends of the primaries (a common point of departure is supposed), its generic attribution remains uncertain. 2. palaeontological description genus montenegrella sokač & nikler in granier & deloffre, 1993, non sokač & nikler, 1973 montenegrella? gracilis n. sp. (pls. i-ii) origin of the name: the species has been named after the thin, tendril-like stalks of the primary branches, giving the alga the appearance of a tender structure. type locality: mt. biokovo (south croatia), in a road cut situated approximately in the middle between the vošac mountain hut and the sv. jure peak (1762 m, fig. 1). coordinates: 43o 19’ 36’’ n, 17o 03’ 44’’ e. type stratum: the sample kj-18 with the new alga belongs to the level of light brown, well-bedded limestone, with bed thickness ranging from 0.3 to 1.2 m. the microfacies types are fenestral, skeletaland oncoid-bearing, intraclastic grainstone and skeletal–peloidal packstone. the allochems include irregular intraclasts, small pellets, micritized skeletons of benthic foraminifera and gastropods, and, less commonly, oncoids, skeletons and bioclasts of dasycladalean algae, and centripetally micritized shell bioclasts. the lithological succession is represented by an alternation of mudstone, algal and foraminiferal wackestone, and sporadic occurrences of skeletal–intraclastic grainstone. the stratigraphic position of sample kj-18 is the upper barremian, determined by the rich dasycladalean associasokač & grgasović: montenegrella? gracilis n. sp., a new calcareous alga (dasycladales) from the upper barremian of mt. biokovo (dinarides mts., croatia) geologia croatica 175 tion, and with the first occurrence of palorbitolina lenticularis in the strata immediately above the investigated sample. the first occurrence of p. lenticularis, before the occurrence of the early aptian praeorbitolinids, indicates a late barremian age in the karst dinarides (velić, 2007), although the lowermost occurrence of this foraminifera has been proven to be early barremian (granier et al., 2013). for a detailed description of the fossil assemblage, geographic and stratigraphic position see sokač (2004, 2005, 2007), sokač & grga so vić (2004, 2008). holotype: transverse-oblique section in slide kj18/126, pictured in pl. i, fig. 4. isotypes are re presented by variously oriented sections figured in pls. i-ii. the original material will be stored in the collection of holotypes at the croatian natural history museum in zagreb, demetrova 1. diagnosis: cylindrical, unbranched thallus with a relatively narrow central cavity (small value of d) with regard to the outer diameter (d). bipartite branches alternate in densely arranged whorls. primaries are characterized by a thin tendril-like stalk, which, in the outer half of their total length, visibly thickens, becoming club-shaped or ellipsoidal. the secondaries are of unclear shape, appearing to be very short, their existence being indicated by a funnel-shaped widening as a con tinuation of the primaries’ distal ends. the shape and the dimensions of the funnel-shaped widening suggest their common starting point. dimensions in mm maximum observed thallus length l 6,80 outer thallus diameter d 1,76-3,90 innet thallus diameter d 0,40-1,20 relation inner/outer diameter d/d 0,150 – 0,330 distance between neighbouring whorls h 0,16-0,24 proximal diameter of primaries p 0,04-0,09 distal diameter of primaries p’ 0,22-0,34 length of primaries l 0,92-1,56 number of primaries per whorl w 26-30 inclination of primaries α 30o-40o length of secondaries l’ ? 0,16-0,20 number of secondaries on a primary branch w’ ? 3-4 description: the new species is characterized by an unbranched, cylindrical thallus, consisting of fineto mediumgrained mosaic calcite which replaced the original, probably aragonite skeleton. the clearly delimited, narrow central cavity occupies from about 15% up to one third of the total diameter at the most. the outer surface of the thick calcite envelope, perforated by pores and small canals of the branches, depending on the position of the plane of section, appears to be rather uniformly abraded, thus being relatively regular and usually delimited by a thin, dark micritic rim. the inner surface is smooth and also delimited by a thin micritic rim. bipartite branches are arranged in regular whorls; in the neighbouring whorls, the primaries occupy alternating positions (pl. ii, figs. 1, 4). phloiophorous primaries are characterized by a thin, tendril-like stalk with a diameter of 0.04 to 0.09 mm in their proximal half; they gradually widen into a swollen distal half (p’ 0.22-0.34 mm), thus assuming, in general, a relatively regular club-like shape (pl. i, figs. 1, 4, 8). in oblique and oblique-tangential sections, the swollen distal parts appear as more or less rounded or ellipsoidal pores (pl. i, figs. 1, 6; pl. ii, figs. 1, 4). the variable shape of the pores, some of which suggest the possibility of being vertically compressed, is probably only the consequence of relationships between their being vertically inclined and the position of the plane of section. the branches grow obliquely and are directed upwards. the direction of their growth makes an angle with the horizontal plane section of (α) 30°-40°. whorls are comparatively densely arranged, so that the distal parts of individual branches touch mutually, both within the same whorl and with the branches of the neighbouring whorls (pl. i, fig. 2; pl. ii, fig. 4). the existence of secondaries seem without question; however, due to corrosion of the outer surface they are mostly erased, only seldom being preserved, and poorly visible in only some parts of some sections (pl. i, fig. 4). despite not knowing how much of the outer surface of the skeleton has been abraded during transport, the secondaries seem to have been very short indeed (length l’ 0.16-0.20 mm). the existence of secondaries, their dense arrangement, and probably their common starting point is also indicated by partially visible, shallow, funnel-shaped widenings occurring at the distal ends of the primaries (pl. i, figs. 4, 8; pl. ii, fig. 8). however, their number and shape remain unknown. the shape and width of the funnel-shaped widening suggests a phloiophorous shape for the secondaries and 3?-4 in number per bundle. these uncertainties in the position and growth form of the secondaries make the generic attribution debatable. similarities and differences: with regard to the originally described species of montenegrella, the new species is distinguished by the regularity of the primaries, pronounced thin, tendril-like stalks in the proximal half and regular, clubshaped or ellipsoidal swelling in the distal (outer) half of the calcareous envelope. in addition, it is distinguished by a thick calcite envelope and thin, regularly shaped central cavity. with regard to montenegrella florifera bernier and m. corbarica jafrezzo, the difference is visible in the distance between neighbouring whorls (h), the shape of the primaries, and in clearly visible and well-developed, rather massive, secondaries in both these species. with regard to suppiluliumaella transdanubica (dragastan) and s. alimani (dragastan), of which the latter does not show any remarkable difference to the type-species of suppiluliumaella, the differences concern the value of the inner diameter, shape of the primaries, and independent growth of the secondaries out of the primaries’ distal ends, as distinct from these characteristics being well-developed in the mentioned species. with regard to s. leini dragastan and s. riedeli dragastan, their unclear photographic illustrations make direct comparison impossible. the differences to s. elliotti bakalova and s. schroederi barattolo concern the shape and massiveness of the primary branches, the relationship between the inner and outer diameters, and the growth form of the secondaries, regarding the same features in the new species. geologia croatica 68/3geologia croatica 176 acknowledgement the authors would like to thank reviewers felix schlagint weit (munich) and bruno granier (brest) for their very helpful and constructive comments which improved the manuscript. this study was supported by the ministry of science, education and sports of the republic of croatia through projects 181-1811096-1093, 181-1951126-1134, and 1951953068-0242. references barattolo, f. (1984): osservazioni su suppiluliumaella schroederi n. sp. (alghe verdi, dasicladali) del cenomaniano del matese (appennino meridionale, italia).– boll. soc. natur. napoli, 92 (1983), 1–47. bassoullet, j.p., bernier, p., conrad, m.a., deloffre, r. & jaffrezo, m. (1978): les algues dasycladacées du jurassique et du crétacé.– géobios, mém. spéc, 2, 330 p. bernier, p. (1978): une nouvelle algue dasycladacee du portlandien du jura meridional francais: montenegrella florifera nov. sp.– geobios, 11/1, 141–147. bucur i.i. (2001) – paleozoic and mesozoic formations in the reşiţamoldova noůa zone (south carpathians).– in: bucur, i.i., filipescu, s. & săsărăn, e. (eds.): algae and carbonate platforms in the western part of romania, field trip guide, 4th regional meeting of ifaa. cluj university press, cluj-napoca, 137–166. bucur, i.i. & săsărăn, e. (2005): micropaleontological assemblages from the upper jurassic-lower cretaceous deposits of trascău mountains and their biostratigraphic significance.– acta pal. romaniae, 5, 27–38. carras, n. (1995): la piattaforma carbonatica del parnasso durante il giurassico superiore-cretacico inferiore (stratigrafia ed evoluzione paleogeografica).– mesonghion, athene, 232 p. (in greek, with italian summary). carras, n., conard, m.a. & radoičić, r. (2006): salpingoporella, a common genus of mesozoic dasycladales (calcareous green algae).– revue de paléobiologie, 25/2, 457–517. dragastan, o. (1978): microfaciès de la série calcaire cretacée inférieure d'aliman (dobrogea de sud).– dari de seama ale sedintelor, bucuresti, 64/4, 107–136. dragastan, o. (1989): calcareous algae (new and revised), microproblematicae and foraminiferida of jurassic – lower cretaceous deposits from the carpathian area.– rev. espan. micropal., 21/1, 5–65. elliot, g.f. (1968): three new tethyan dasycladaceae (calcareous algae).– palaeontology, 11/4, 491–497, 3 pl. (93–95). gawlick, h.j., frisch, w., hoxha, l., dumitrica, p., krystyn, l., lein, r., missoni, s. & schlagintweit, f. (2008): mirdita zone ophiolites and associated sediments in albania reveal neotethys ocean origin.– int. j. earth sci., 97, 865–881. granier, b. & deloffre, r. (1993): inventaire critiques des algues dasycladales fossiles. ii° partie – les algues dasycladales du jurassics-ii° partie – les algues dasycladales du jurassicssique et du crétacé.– rev. paléobiol., 12/1, 19–65. granier, b., clavel, b., moullade, m., busnardo, r., charollais, j., tronchetti, g. & desjacques, p. (2013): l'estellon (baronnies, france), a "rosetta stone" for the urgonian biostratigraphy.– carnets de géologie (notebooks on geology), 2013/04, 163–207. jaffrezo, m. (1975): montenegrella corbarica n. sp., algue dasycladacee du neocomien des corbières (france), avec une clé de détermination des dasycladacées jurassiques et crétacées a deux ordres de ramifications.– geol. rom., 14, 155–163. michetiuc, m.c., catincut, c. & bucur, i.i. (2008): microfacies and microfossils of the lower cretaceous limestones from the southern part of vâlcan mountains.– acta pal. romaniae, 6, 217–227. schlagintweit, f., gawlick, h.-j., missoni, s., lein , r. & hoxha, l. (2006): late jurassic to early cretaceous dasycladales and benthonic foraminifera from the munella carbonate platform s. l. of the mirdita zone (albania).– in: sudar, m., ercegovac, m. & grubić, a. (eds.): proceedings xviiith congress of the carpathianbalkan geological association (2006), 527–530. sokač, b. (2004): on some peri-mediterranean cretaceous dasyclad species (calcareous algae; dasycladales) previously assigned to different genera.– geol. croatica, 57/1, 15–53. sokač, b. (2005): linoporella vesiculifera n.sp., a new calcareous alga (dasycladales) from the upper barremian of mt. biokovo (karst dinarides, croatia).– geol. croat., 58/2, 119–131. sokač, b. (2007): stop 11 – upper hauterivian algae – south of mali troglav.– in: grgasović, t. & vlahović, i. (eds.): 9th international symposium on fossil algae – croatia 2007, field trip guidebook and abstracts. croatian geological survey, zagreb, 79–81. sokač, b. & grgasović, t. (2004): megaporella nikleri n.sp. new calcareous alga (dasycladales) from the upper barremian of mt. biokovo, croatia.– riv. ital. paleont. strat., 11/3, 651–658. sokač, b. & grgasović, t. (2008): on some salpingoporella species from the lower cretaceous of dinaric karst.– geol. croat., 61/2–3, 251–271. sokač, b. & nikler, l. (1973): calcareous algae from the lower cretaceous of the environs of nikšić, crna gora (montenegro).– paleont. jugoslav., 13, 7–57. velić, i. (2007): stratigraphy and palaeobiogeography of mesozoic benthic foraminifera of the karst dinarides (se europe).– geologia croatica, 60/1, 1–113, 26 pl. manuscript received july 23, 2015 revised manuscript accepted september 16, 2015 available online october 31, 2015 figure 1: (a) general location of the sample kj–18 locality in the croatian territory. (b) simplified map of the area of the central biokovo mt., type locality of montenegrella? gracilis n.sp. (from sokač, 2005). sokač & grgasović: montenegrella? gracilis n. sp., a new calcareous alga (dasycladales) from the upper barremian of mt. biokovo (dinarides mts., croatia) geologia croatica 177 plate i montenegrella? gracilis n. sp. 1 longitudinal-oblique section. slide kj-18/4, x22. 2 oblique section. slide kj-18/141, x14. 3 tangential-longitudinal section. slide kj-18/142, x17. 4 transverse-oblique section. holotype. slide kj-18/146, x17. 5–6 longitudinal-tangential sections. slides: fig. 5, kj-18/245, x22; fig. 6, kj-18/242, x14. 7 a montenegrella? gracilis n. sp., transverse section. b cylindroporella lyrata masse & luperto-sinni, longitudinal-tangential section. slide kj-18/93, x14. 8 transverse section (fragment). slide kj-18/216, x22. geologia croatica 68/3geologia croatica 178 plate ii montenegrella? gracilis n. sp. 1 oblique-tangential section. slide kj-18/27, x17. 2–3 oblique sections. slides: fig. 2, kj-18/229, x14; fig. 3, kj-18/156, x14. 4 tangential section. slide kj-18/218, x17. 5–7 transverse sections. slides: fig. 5, kj-18/64, x14; fig. 6, kj-18/183, x17; fig. 7, kj-18/215, x22. 8 part of oblique section. slide: kj-18/16, x22. 9 a cymopolia velici sokač & nikler, transverse section. b montenegrella? gracilis n. sp., fragment. section kj-18/214, x22. 2017 | 70/3 | 115–161 | 1 fig. | 19 pls. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the genus selliporella sartoni & crescenti, 1962 was established on the basis of inadequately illustrated, fragmented sections of individual whorls. thus, the lack of more complete parts of thallus resulted, then, in an incomplete diagnosis as follows: „essentially cylindrical thallus, with generally detached and separately fossilized whorls. fertile whorls in a basket shape, each one formed by laterals of two or more superposed rows. phloiophorous laterals are welded together. laterals of the same row communicate with one another; but the laterals of the various rows of the same whorl have rare, sporadic and often absent communication.“ (sartoni & crescenti, 1962). such inadequate and even, to some extent confusing, diagnosis resulted in fragments or sections of different characteristics being ascribed to selliporella donzellii, and even in the description of a new species, teutloporella gallaeformis radoičić, 1965, which, after the establishment of the new genus neoteutloporella bassoullet et al., 1978, will be ascribed to the latter. in neither species description (selliporella donzellii and teutloporella gallaeformis) are the articulation of the thallus and the bipartite laterals explicitly mentioned, though radoičić (1965) did show two sections with visible articulation (radoičić, 1965, pl. iv, figs. 3-4). besides, in the explanatory note to a figure radoičić, (1965, pl. iii, fig. 3), mentioned a type of annulation, which, however, she supposed to be a secondary feature, due to subsequent break-off, and which, therefore, cannot be related to original thallus annulation. though frequently mentioned in various papers as evidence or confirmation of stratigraphic age, selliporella donzellii was not, at that time, analysed in more detail. a short repeated description given by nikler & sokač (1967) was in many respects inaccurate and confusing, along with the photographs attached, which failed to give any contribution to a better understanding of the species-specific – and thus, implicitly, to the genus-specific – characteristics. in a later, more complete description of both the genus selliporella and the species selliporella on the species of the genus selliporella sartoni & crescenti, 1962 from the middle jurassic of the coastal dinarides of croatia branko sokač & tonći grgasović croatian geological survey, sachsova 2, 10000 zagreb, croatia; (tgrgasovic@hgi-cgs.hr) doi: 10.4154/gc.2017.15 abstract an emended diagnosis of the genus selliporella and its type-species, s. donzellii sartoni & crescenti is proposed, based on the proven existence of non-ramified laterals in the mature (basal) part of the thallus and their ramification in its higher (juvenile) parts. given the differences in the morphological characteristics of laterals in the upper parts of the thallus, the type-species has been split into two varieties: s. donzellii var. donzellii sartoni & crescenti and s. donzellii var. galaeformis n. comb. selliporella cornutuformis n. sp. is proposed, characterized by a distinctly articulated (segmented) and spiky thallus, with each primary lateral bearing a bundle of several trichophorous secondaries. the generic attribution of species originally described as diplopora johnsoni praturlon and triploporella neocomiensis radoičić has been reviewed, resulting in their being unified as the same species, which, according to its newly observed morphological characters, has been ascribed to the genus pseudoclypeina. as diplopora johnsoni has been validly described, triploporella neocomiensis becomes, taxonomically, the younger synonym of pseudoclypeina johnsoni (praturlon) n. comb. donzellii, given by sokač & velić (1978), the presence of segments with two or three rows of whorls was explicitly mentioned for the first time, but still with an emphasis on undivided laterals of the piriferous type. however, as later emphasized by barattolo et al. (1992), that addition could not be accepted due to the afore-mentioned morphological characteristics and also because the form illustrated by sokač & velić (1978; pls. i-v) didn’t correspond to the type-species characteristics. a new amended diagnosis of selliporella donzellii sartoni & crescenti was given by barattolo et al. (1992, p. 604). based on analysis of numerous sections from samples collected from a number of localities in the apennines and dinarides, they gave a detailed description concerning the shape and distribution (arrangement) of bipartite laterals, the thallus morphology, with both the sections illustrated (barattolo et al., 1992, pls. i-iv) and with graphic interpretation (barattolo et al., 1992, figs. 1-4). they summed up the characters of the species as follows: „euspondyle dasyclad alga uniformly articulated or, instead, articulated only in some regions of the thallus. each article is provided of primary branches arranged in a couple of secondary branches. the primaries are short, and laterally compressed, they are subrectangular in cross-section. the secondary branches are trichoporous, sturdy, and relatively long; they are proximally perpendicular to the main axis but outwards they bend gradually upwards. they grow in tufts of two on each primary branch.“ based on these characteristics of the type-species, they also gave a summary diagnosis of the genus, and commented on neoteutloporella gallaeformis (radoičić), for which they stated that it „might be“ a higher, non-segmented part of the selliporella donzellii thallus, thus being its younger synonym. as for the form ascribed to selliporella donzellii and illustrated in sokač and velić (1978, pls. i-v), they emphasized its being impossible to be identified with the type-species, but possibly belonging to the same genus (i.e., selliporella). article history: manuscript received august 03, 2017 revised manuscript accepted october 04, 2017 available online october 31, 2017 keywords: selliporella genus, dasycladales, taxonomy, biostratigraphy, dinarides, croatia g eo lo gi a c ro at ic a geologia croatica 70/3116 after extensive investigations of numerous sections in the samples from the dinaridic coastal region, it was noticed that only a part of these sections may be reliably ascribed to selliporella donzellii, within the frame and according to the emended diagnosis of barattolo et al. (1992). quite a large amount of sections, contained in the type-species bearing sample, showed bipartite laterals differing in morphology from what was previously described. some sections, rather rare in the bulk of algal fragments, mixed with variously preserved sections of the type species, differ from those in being distinctly smaller, showing an articulated thallus, and having mutually separated, undivided, clearly piriferous laterals. taken individually, with their completely different morphology of both thallus and laterals, these sections appeared unidentifiable with selliporella donzellii and, at first glance, suggested a possibility of belonging to the genus neoteutloporella (a similar section was illustrated by rado ičić, 1965, pl. iv, fig. 4, and labelled? teutloporella). we identified these sections as representing the basal parts of the thalli of the type-species. however, in reviewing the existing descriptions and amendments, we noticed the lack of more detailed biometric parameter values. thus in the original description (sartoni & crescenti, 1962) there were only three values mentioned (l, d, w) or, if we take neoteutloporella gallaeformis as a younger synonym of selliporella donzellii, two more can be added (l, p). the position of sections figured by sokač & velić (1978, tab. i-v) and ascribed to the type-species, remain unsolved. such open questions resulting from earlier papers, and more of the same, inspired us to undertake a revision of our own earlier determinations and opinions. in this paper, we again analysed numerous algal-bearing samples from several localities in the central and southern dalmatian coastal area (mt. biokovo, the environs of neum, osojnik nw of dubrovnik, as well as the konavle hills se of dubrovnik). the samples analysed and illustrated here have been collected by several researchers from the croatian geological survey (former institute of geology) during the last 30 years or so. their localities with greenwich coordinates are listed below: mt. biokovo: sample ppb-29 43°15 5́6,8´́ n, 17°6́ 33,6́ ´e; sample ppb-125 43°18´33,8´́ n, 17°2 5́8,1́ ´e; sample sb-8 43°16́ 25,2´́ n, 17°6́ 15,7´́ e environs of neum: sample nu-41 42°56́ 28,5́ ´n, 17°37´25,4´́ e environs of village osojnik: sample os-9 42°42’14“ n, 18°4 4́1́ ´e; sample os-79 42°43’29“ n, 18°4 4́0´́ e konavle hills: sample kob-372 42°35´51́ ´n, 18°17´32,3´́ e after the analysis of the aforementioned samples we came to the following conclusions: – selliporella donzellii is highly variable with regard to the morphology of the thallus and laterals, depending primarily on which parts of thallus, i.e. mature or juvenile, are compared; – that the emendation of selliporella donzellii sartoni & crescenti as given by barattolo et al. (1992) is fully applicable only for juvenile (higher) parts of thallus; – that the supposition in the separately given opinion of barattolo and de castro in barattolo et al. (1992), that teutloporella gallaeformis radoičić is a younger synonym of selliporella donzellii, i.e., its juvenile (higher) thallus part, is correct. sections with the characteristic shape and bulkiness of the secondary laterals, usually illustrated under the name teutloporella gallaeformis, should be separated as a new variety of the type-species; – that the sections illustrated in sokač & velić (1978, tab. i-v) under the name selliporella donzellii sartoni & crescenti, whose assignment to that species was questioned by barattolo et al. (1992), doubtlessly belong to the genus selliporella and can be singled out as a new species, introduced here as selliporella cornutuformis n. sp.; – that the biometric parameters of the type-species should be given separately for different parts of its thallus; – that the variability in the building elements of selliporella donzellii is intraspecific, but individual specimens with distinctly pronounced peculiar morphologic characteristics may be separated as varieties of the same species. – that a new description of selliporella donzellii sartoni & crescenti is needed. moreover, discussion of the generic attribution of the species originally described under the name triploporella neocomiensis radoičić, which was subsequently transferred to selliporella is warranted (bucur & săsăran, 2003). 2. systematic palaeontology selliporella donzellii sartoni & crescenti var. donzellii pls. i – ix after studying a large number of variously oriented sections in one or several samples, a new and more complete understanding of the very variable morphology of the thallus as a whole and of changing type and shape of laterals from undivided to divided has arisen. laterals may be present in sections cutting different parts of the thallus, depending on their growth stage. dimensions in mm: a b c l = 10,46 d 0,58–1,70 1,44–2,52 1,70–3,78 d 0,16–0,82 0,48–1,05 0,34–0,98 d/d 0,230–0,500 0,200–0,541 0,210–0,356 h 0,14–0,46 0,20–0,62 0,28–0,30 p 0,04–0,16 – – p´ – 0,05–0,24 0,16–0,30 p´´ – 0,06–0,20 0,18–0,30 l 0,50–0,94 – – l´ – 0,24–0,30 0,20–0,35 l´´ – 0,48–0,72 0,50–1,10 w 6–12 12–20 do 30 α 20–50° explanation of symbols: a – lower (mature) part of thallus; b – middle part of thallus; c – upper (juvenile) part of thallus l – maximum observed length d – outer diameter d – inner diameter d/d – relationship between inner and outer diameter h – distance between consecutive whorls p – diameter of laterals at their widest p´ – diameter of primary laterals p´´ – diameter of secondary laterals at their widest l – length of laterals l´ – length of primary laterals l´´ – length of secondary laterals w – number of laterals per whorl w ‘– number of secondaries on a primary lateral w’’ – number of tertiaries on a secondary lateral α – dip of laterals from horizontal plane g eologia c roatica sokač & grgasović: on the species of the genus selliporella sartoni & crescenti, 1962 from the middle jurassic ... 117 the calcareous thallus has a rather variable shape, depending on the distance between neighbouring whorls, the shape of undivided or divided laterals, and their inclination. basal (= mature) part of thallus is distinctly articulated, and thus acquiring a spiny (spinose) shape, as a result of clearly separated whorls of piriferous laterals with distally individualized calcareous envelopes (pl. i, figs. 1-5, 7-9). going upwards, laterals became divided (pl. i, fig. 6, pl. iv, figs. 1-2; pl. v, fig. 5), resulting in more massive articles, with, in some sections, visible annulation in between (pl. iv, figs. 1-2; pl. vi, fig. 8; pl. vii, fig. 7; pl. viii, fig. 1). in other sections, annulation is unclear or absent. each article represents one whorl. in higher (= juvenile) parts of the thallus, the distance between neighbouring whorls gradually diminishes, while the diameter of both primaries and secondaries, as well as the height of the articles, visibly increases, with reduced annulation which leads to the appearance of a seemingly non-articulated thallus. in some sections of the juvenile part of the thallus horizontal fissures are visible (pl. vi, fig. 8, part.; pl. vii, fig. 6, part.; pl. viii, figs. 6,8), which represent reduced annulation resulting from calcification of the individual whorls of ramified laterals. vertical, oblique, or irregular, sections, observed in places (pl. vii, fig. 1-2, bottom; pl. viii, fig. 9), mainly divide pairs of secondary laterals, as a result of the calcification of individual laterals. generally, annulation is typically present in the basal part of the thallus, more or less displayed in middle parts, and reduced in the upper parts. that is a result of differences in the distance between neighbouring whorls and the shape and the inclination of the laterals, together with the presence of individual calcareous sheets (de castro, 1997) of laterals. in its basal part, the thallus is cylindrical and distinctly annulated, becomes slightly club-shaped, with reduced annulation and thus acquiring a seemingly compact shape (pl. iv, fig. 8; pl. v, fig. 2; pl. vii, fig. 6). outer surfaces of the upper parts, strewn with shallow spines, are a consequence of individual calcareous sheets of the secondaries’ distal ends (pl. v, fig. 2; pl. vi, figs. 2-3; pl. vii, figs. 2-3; pl. viii, fig. 5). in the basal and middle parts of the calcareous skeleton, the central cavity is cylindrical and delineated with a continuous thin black micrite layer (pl. i, figs. 3-4; pl. ii, figs. 1, 3-4, 7-8; pl. iv, figs. 1-7, 8-9). in the upper parts of the thallus, this black layer is seldom continuous (pl. v, part. figs. 1-2, 4; pl. viii, figs. 2-3, 6); more frequently, it disappears due to erosion of the thallus interior (pl. v, figs. 1-2) or due to the connected pores of the proximal ends of neighbouring primary laterals (pl. iv, fig. 8; pl. v, fig. 6; pl. vii, fig. 3). in earlier papers (sartoni & crescenti, 1962), these features were described as circular „annular“ canals. the central cavity occupies, on average, 20-40% of the outer thallus diameter. euspondylity is clearly visible in all parts of the thallus. as already mentioned, going from the mature to juvenile parts of the thallus, the type of laterals, their shape, and their number per whorl change. in the basal thallus parts, the laterals are piriferous simple (undivided), not distinctly pear shaped (pl. i, figs. 1-5, 7-9; pl. ii, figs. 2, 4-5, 7-9; pl. iv, fig. 1 bottom). by their proximal ends, the laterals of the same whorl are mutually in close contact, thus forming an uninterrupted calcareous ring. (pl. iii, figs. 1-3, 6-7). more distally, the laterals of the same whorl grow more wide apart and became more clearly separated, each one being enveloped in a thin individual calcareous sheath, giving the thallus a distinctly spiky (spinose) appearance. the number of laterals in a whorl at this level of the thallus increases gradually from a minimum of 6 (pl. iii, fig. 7) to 10-12 (pl. iii, figs. 1-2, 6, 8-9). the laterals are directed obliquely upwards, under an angle of 20°50°, more steeply in the upper thallus parts (pl. i, figs. 1, 3-5, 7-8), also, going to higher levels, the simple (undivided) laterals pass into ramified laterals, more gently inclined to the horizontal plane (pl. iv, fig. 1). the appearance of the first ramified laterals is characterized by variably shaped primaries, ranging from short tubular (pl. iv, fig. 3, 5, 9), proximally more or less irregularly widened (pl. iv, part fig. 5, 7, fig. 8 bottom), to visibly swollen (pl. iv, fig. 1 top, fig. 8 top). in the middle part of the thallus, the proximal ends of the primaries are, in general, well preserved, so that the central cavity is still clearly defined (pl. iv, figs. 2-7, 9-10, 8 bottom). articulation here can be either clearly pronounced (pl. iv, figs. 1-2 top; pl. vi, fig. 8; pl. vii, figs. 5, 7) or just indicated, but barely observable. going upwards, the primaries became larger, of ellipsoidal, or irregularly circular shape (pl. v, figs. 2-3, 6) or, sometimes, with lowered (dropped) bases, acquiring a stocky, basket-like shape (pl. v, fig. 2; pl. vi, fig. 1; pl. vii, fig. 5), as mentioned and illustrated by barattolo et al. (1992, fig. 3), thus indicating the pronounced variability in the primaries’ shape. in the upper parts of the thallus, the number of laterals per whorl varies from 20 to 30. the distance between neighbouring whorls decreases, leading to ever more close contact of their laterals (pl. vi, fig. 1), sometimes to the joining of their pores in their proximal parts (pl. v, fig. 6; pl. vii, figs. 2-3). in this region of the thallus, the primaries are most frequently, partly or completely, destroyed, their shape being recognizable only with difficulty, with a secondarily widened and indistinctly delineated central cavity (pl. iv, fig. 8 top; pl. v, part. fig. 2; pl. ix, fig. 1). such an appearance is caused by the laterals being pressed together and, consequently, having thinner (or non-existent) calcareous envelopes, easily prone to destruction. each primary lateral bears a pair of piriferous secondaries, of which the lower one is always larger, attaining up to three times a larger diameter then that for the upper lateral, and having a more distinctly piriferous shape. in tangential sections through the upper parts of the thallus, the different diameter of the secondaries belonging to the same pair, is indicated by alternately occurring large and smaller pores (pl. vi, fig. 8; pl. vii, figs. 6-7; pl. viii, fig. 8). the secondaries, though being approximately horizontal in their proximal parts, going outwards gradually bend upwards and their calcareous envelopes become separated. in the distal tangential sections, this feature gives a picture of an joint envelope of the same pair (outer parts of the skeleton being fissured), whereas in the top parts it appears as single circular pores with individual envelopes (pl. vii, fig. 2 bottom, pl. viii, fig. 9; pl. ix, fig. 2 top) and shallow spinose outer surface. laterals of the same pair grow one above the other, but going upwards, the direction of growth of the thinner, upper lateral slightly diverges sideways, in relation to the lower, larger lateral. in tangential sections this appears as an alternating distribution of rows with larger pores, belonging to larger lower laterals, and rows of smaller pores, deriving from thinner, upper laterals of neighbouring pairs of the same whorl (pl. vii, fig. 6-7; pl. viii, fig. 8; pl. ix, fig. 2 top). variability concerning the size and shape of the lower, larger secondary lateral is very frequent, whereas the dividing (branching) of the secondaries is anomalous and occurs only rarely (pl. v, fig. 3 arrow). specimens with enormously large and visually variously shaped secondaries have been singled out as the new variety. the species is most likely cladosporous, a conclusion based on the large relative size of its laterals. this may be supported by the presence of single micritic bodies of 0.10 mm in diameter, possibly representing dispersed cysts, that have been observed in g eo lo gi a c ro at ic a geologia croatica 70/3118 the primaries, and more frequently in the larger of the secondaries (not illustrated). the type species is characterized by a wide range of morphology from the basal to the top part of the thallus. this is due to the type of laterals, their gradual increasing number per whorl going upwards, their variable declining angle in relation to the central axis of growth, variable distance between the neighbouring whorls, their more or less pronounced growth (becoming larger) of the primaries and secondaries, leading to variable values of outer and inner diameters. we propose the following emended diagnosis of selliporella donzellii sartoni & crescenti: the type species of the genus selliporella is clearly euspondyle, cylindrical to slightly claviform shape, distinctly articulated in the lower parts and with reduced annulation in the upper parts. in the lower part, it has undivided piriferous laterals, each having a distally individualized calcareous envelope. going upwards, the undivided laterals pass into clearly differentiated primaries and secondaries. each primary lateral bears a pair of more or less distinctly piriferous secondaries, which diverge laterally. in accordance with the emended species-specific diagnosis, we propose the following emended generic diagnosis of the genus selliporella sartoni & crescenti: cylindrical to slightly claviform, more or less segmented thallus. laterals arranged in whorls, undivided in the lower part of the thallus, divided in the upper. primaries of variable shape, from tubular to more or less inflated. secondaries trichophorous to piriferous. selliporella donzellii sartoni & crescenti var. gallaeformis (radoičić) n. comb., n. var. pl. iii, fig. 13a; pl. viii, fig. 6b; pls. x-xii the establishment of a new variety within selliporella donzellii sartoni & crescenti is based on differences between individual biometrics in the upper thallus part with regard to the same parameters in the typical variety. this results in morphological variability, intensity of calcification, and, thus, the state of preservation. the lack of sections of transition from the lower to the upper part of the thallus in s. donzellii var gallaeformis may be a question, but the discovery of such a section is merely luck. for s. donzellii, along with its numerous illustrations by many authors, the transition from the lower to the upper part of the thallus has only been observed in a few sections, in the 50 years from its first description. in numerous sections derived from the same sample (o-79), the new variety is represented by about 10% of the total number of sections of the various parts of the thallus of the type species. the analysed and illustrated sections (pls. x-xii) have been ascribed to the upper parts of the typical variety, because other thallus parts, which would, by their characteristics, diverge from the above described in the typical variety of selliporella donzellii, have not been observed. moreover, some sections (pl. ix, figs. 3-4) partly include features characteristic of both varieties, which, in such cases, makes their undoubted separation impossible, but clearly indicates their belonging to the same species. in the analysed material, selliporella donzellii var. gallaeformis is present with variously oriented sections and frequently preserved only by the outer, peripheral parts of the thallus (pl. iii, fig. 13a; pl. x, figs. 4-6), with more or less preserved secondaries. this makes a more detailed insight into the inner morphology impossible, particularly for the primaries, and also prohibits obtaining more numerous biometric parameters and their mutual relationships. the outer diameter (d) can reach 5 mm. as a rule, the central cavity is secondarily widened through destruction of the primaries and the proximal parts of the secondaries (pl. x, figs. 3-4; pl. xiii, figs. 1, 4, 6), most probably because of poorly developed calcification in this part of the alga (pl. x, fig. 9; pl. xi, figs. 7, 9; pl. xiii, fig. 8). only a few sections (pl. x, fig. 9; pl. xi, figs. 7, 9; pl. xii, fig. 8) enable partial, but insufficient, insight as to the shape and dimensions of the primaries. the impression is, they are much larger, more irregular, and, more often than in the typical variety, proximally compressed, both in the case of the laterals of the same whorl and those of the neighbouring whorls, which makes questionable the existence of an integral inner calcareous envelope, suggesting, instead, its honey-combed structure. secondary laterals are of the piriferous type, and because of the destruction of their proximal parts, their growth in pairs and the relationship with the primaries are only rarely observable. thus, these features make the main and recognizable characteristics of the new variety. in sections, the visibly piriferous secondaries are very large, having much larger diameters than the same values in the typical variety, and are of a different shape, being distinctly piriferous (pl. x, figs. 2, 5; pl. xi, figs. 4, 9), baggy elongated (pl. x, fig. 8; pl. xi, figs. 1, 8; pl. xii, figs. 1-2), or irregular (pl. x, figs. 1, 4; pl. xi, fig. 7; pl. xii, figs. 7-8), and different shapes may appear in the same thallus. secondary laterals of the same pair, in the typical variety being distinguishable by different diameters (lower ones are larger and with larger diameter, upper ones thinner), in this variety this distinction can be seen only in a few sections (pl. x, fig. 3 top), so this feature remains unclear. the secondaries are distinctly swollen in the first third or half of their total length, except for those that are baggy or irregularly shaped (pl. x, figs. 2, 6, 9; pl. xii, fig. 8). more distally, more or less bent upwards, they, either gradually or abruptly, taper into spiny terminations of individual calcareous envelopes. because of being swollen, the secondaries of both the same whorl and of the neighbouring whorls are tightly pressed together, compressing each other and leading to vertical and lateral deformations. in tangential sections or in part of the tangential sections, vertical or approximately vertical sections of laterals appear as more or less rounded (pl. x, fig. 3; pl. xi, figs. 5-6), polygonal or irregular, sometimes distinctly deformed pore shapes (pl. x, part. fig. 6; pl. xi, figs. 4, 6; pl. xii, fig. 3). individual circular bodies, 0.1 mm in diameter can be observed, dispersed in the secondaries’ cavities, only rarely grouped together within a common envelope, elliptical in section, with longer axis of 0,24-0,28 mm, shorter axis of 0,15-0,17 mm, and 6-?10 particles in a group (pl. xi, fig. 5; pl. xii, figs. 9-10, arrow). these circular bodies are probably cysts. selliporella cornutuformis n. sp. pl. xiii – xvi the species name derives from the spiky segments, which give such an appearance to the whole thallus. type locality: mt. biokovo (south croatia), in a road cut situated between „lemišini doci“ and „ravna vlaška“ localities (fig. 1). it is stop 9 of the 9th international symposium on fossil algae field trip (sokač & velić, 2007). coordinates: 43o16’25.2“ n, 17o6’15.7“ e. type stratum contains numerous algal remnants in algal fenestral biomicrites with corrosion cavities, geopetal internal sediment and microcrystalline cement. sporadically late diagenetic dolomite appears. the sedimentary environment is determined g eologia c roatica sokač & grgasović: on the species of the genus selliporella sartoni & crescenti, 1962 from the middle jurassic ... 119 as the upper intertidal zone with vadose diagenesis and shortterm emersions with palaeokarstification. holotype: longitudinal, slightly oblique section in slide sb8b/12, figured in pl. xiv, fig. 2. isotypes are represented by variously oriented sections, figured in pls. xiii-xvi. the entire material of branko sokač’s personal collection in the croatian geological survey will be permanently stored, after publication, in the croatian natural history museum, zagreb. diagnosis: cylindrical, slightly claviform skeleton, distinctly articulated; comparatively regular central cavity slightly constricted in the level of whorls and slightly widened between neighbouring whorls, situated rather far apart. each article bears one whorl of ramifying laterals. primary laterals are small, tuberous or elongated, bearing secondaries in a finger-like arrangement. the number of laterals per whorl increases from the basal to upper parts of the thallus. secondary laterals of the piriferous type, with variously inclined growth directions and distally individualized calcareous envelopes give the alga a distinctly spiky (spinose) appearance. description: generally cylindrical skeleton is distinctly articulated. slightly claviform shape is due to gently but gradually increasing of the segments’ outer diameter from the basal to the top parts (pl. xiii, fig. 1). each article represents the calcified part between the ramified laterals of the same whorl. the distance between consecutive whorls is relatively large, but varies from specimen to specimen. height and diameter of individual articles gently increases from the basal to the top part of the thallus, depending on the number, length, and inclination of the laterals. (pl. xiii, fig. 1). the calcareous envelope between the segments is the thinnest immediately above the lower segment and slightly thickens going toward the upper one, thus acquiring the shape of an inverted cone which passes, more or less abruptly, into the next (superimposed) segment (pl. xiii, figs. 3, 5-6; pl. xiv, figs. 1-2, 5). the calcareous skeleton is composed of grainy calcite (sparite), bordered by thin, black, micritic envelopes. sparry crystals figure 1. location of selliporella cornutuformis n. sp. type locality in the central biokovo mt. (arrow). map: opentopomap.org. g eo lo gi a c ro at ic a geologia croatica 70/3120 represent the filling of the mould cavity, which remained after the primary, most probably aragonitic, skeleton, was dissolved. a thin micritic lining, enveloping the central cavity and the inner parts of laterals, is, generally, of very uniform thickness (pl. xiii, fig. 1 lower part; pl. xiv, figs. 2-3, 5-6; pl. xv, figs. 6, 8-11; pl. xvi, figs. 9-11) and possibly represents the primary micritic algal envelope. in places, this micritic envelope is of uneven thickness, sometimes in the interior of the thallus and more frequently on the outer wall, being probably the result of the activity of endolithic and epilithic microbes. the central cavity displays a more or less well pronounced narrowing at the levels of whorls, and slight widening in the intervals between the whorls (pl. xiii, figs. 1, 3; pl. xiv, figs. 2, 5; sokač & velić, 1978, pl. i, fig. 3). the euspondyle character of the species is pronounced by clearly visible, mutually separated whorls, which, in the basal parts, bear undivided laterals, and in the upper parts, ramifying ones. the unramified, piriferous laterals of the basal parts of the thallus, are inclined steeply upwards (pl. xv, fig. 8), and going upwards pass into ramified primaries and secondaries (pl. xiii, fig. 1; pl. xv, fig. 5; pl. xvi, fig. 7). the exit of a lateral from the central cavity is realised through a tiny pore, which continues into a short tubular canal (pl. xiii, fig. 3; pl. xiv, fig. 5; pl. xv, fig. 1 arrow, 13), which often suddenly widens into a tuberous shaped swelling (pl. xvi, fig. 5, arrow; sokač & velić, 1978; pl. i, fig. 3), longitudinally elongated (pl. xiv, fig. 5) or globular shape (pl. xv, fig. 6 arrow,?fig. 10-11; sokač & velić, 1978, pl. iii, fig. 5) and from which in finger-like arrangement, piriferous secondaries grow out. in spite of the large number of variously oriented sections, the relationship between the proximal swelling of the primary lateral and the secondary laterals, remain unclear. the piriferous secondaries, directed toward the outer surface, grow in various directions, directed both upwards and downwards (pl. xiii, figs. 1, 4-6; pl. xvi, figs. 5-6). in segments with ramified laterals, in different planes of section, the visible number of the secondaries per primary lateral varies from 3 to 4 (pl. xiii, figs. 4-5; pl. xv, figs. 1, 4, 6). in deeper tangential sections of individual segments, in the supposedly upper parts of the thallus, the pores suggest a bundle of as much as five secondaries (pl. xiv, fig. 8; pl. xv, fig. 12), which, however, remains questionable with regard to the possibility of intergrowth of neighbouring laterals. individual calcareous sheets of the secondaries distally separate, becoming independent and sticking out like spines. the spines are fragile and the peripheral parts of the thallus are therefore partly or completely eroded, which makes the full value of the outer diameter (d) inadequately defined. similarities and differences: selliporella cornutuformis n. sp. includes the main characteristics of the genus, comparable to the type species: euspondility, unramified or ramified laterals depending on the growth age of thallus (lower or upper part), distally individualized secondaries, articulation of the skeleton, and similar values of biometric parameters. in addition to the similarities, specific characteristics of the two species enable their clear separation. selliporella cornutuformis n. sp. is characterized by a much larger distance between the neighbouring whorls, strongly pronounced alternation of articles, mutually connected by conical parts of the thallus below the whorls along the entire length of the skeleton, which is lacking in the upper parts of selliporella donzellii. in the upper parts of the type species, the central cavity is often secondarily widened, due to erosion of poorly calcified densely arranged whorls, and clearly bordered by a micritic envelope in the lower parts of the thallus, as distinct from the new species, in which the central cavity is clearly delimited along the whole length, with constrictions at the level of whorls and slight widening in the intervals between the whorls. the other main difference between the two species concerns the shape of the primary laterals and the number of the secondaries. in the type species, the laterals in the upper part of the thallus grow out in pairs, the lower lateral being, as a rule, larger and distally more or less directed upwards, with individualized calcareous envelopes only at their distal ends. in the new species, with only primary laterals in the basal part, with their ramifying in the upper parts, the number of secondary laterals varies from 3 to 4 (questionably 5). as distinct from the type species, in the new species the piriferous secondaries are of more uniform diameter along their length, diverging from each other and directed both upwards and downwards. in the new species, the individualization of calcareous envelopes of the secondaries occurs as early as in the first third or half of their total length, giving the segments a clearly spiky appearance, as distinct from the type species, in which the separation of calcareous envelopes of individual secondaries occurs only at their distal ends. stratigraphic position: at all localities where observed, selliporella cornutuformis n. sp. derives from various levels of the selliporella donzellii biozone. the accompanying fossil contents, varies from locality to locality. it is most frequently associated with more or less numerous sections of the type species, with clear predominance either of the new species, or of the type species. at the osojnik locality (sample o-79), in the wealth of algal remains, the type species is represented by both varieties, accompanied by frequent sections of uragiella ragusina sokač and particularly numerous salpingoporella croatica sokač (the latter has been wrongly considered synonymous with salpingoporella annulata carozzi by carras et al., 2006, p. 160). based on foraminiferal assemblages from both underand overlying beds, velić (2005, 2007) defines the range of the type species selliporella donzellii sartoni & crescenti in the mt. biokovo area as extending from the early bajocian to the late bathonian. this also defines the stratigraphic range of the new species. note on the generic attribution of the species originally described as triploporella neocomiensis radoičić, 1963 the generic attribution of the species originally, but invalidly, described as triploporella neocomiensis radoičić, has been, for years past, considered by several authors. most lately it was ascribed to selliporella by bucur & săsăran (2003), which motivated us to include it in this paper. diagnosis of triploporella neocomiensis, as described by radoičić (1963), represented this alga by an articulated thallus and with a broad central cavity. each article corresponds to one whorl of 16 spherical, somewhat laterally compressed, primary laterals, each bearing a bunch of about 10 secondary laterals of variable length. at the same time, while the paper of radoičić (1963) was in press, praturlon (1964) established diplopora johnsoni, with approximately identical characteristics. this great similarity between the two species, prompted bucur & săsăran (2003) to publish comparable, side by side, tables of their biometric parameters and the description of important morphological characteristics, leaving the conclusion of their identity (i.e., synonymy), open, with the recommendation to restudy the type material of diplopora johnsoni praturlon. if this recommendation is accepted, it would question the correctness of a number of previous emendations and novae combinationes of numerous species belonging to various genera. in our opinion, triploporella neocomiensis radoičić, 1963, in g eologia c roatica sokač & grgasović: on the species of the genus selliporella sartoni & crescenti, 1962 from the middle jurassic ... 121 spite of minor differences in the original author’s description, gains its validity only in the paper of radoičić (1975), thus being clearly the younger synonym of diplopora johnsoni praturlon, 1964. the generic attribution of these species, which were in earlier papers attributed to various genera, suggests the necessity of further analysis, based on both a comparison of the literature data and the analysis of our material, collected from the lower cretaceous deposits of mt. dinara and the island of mljet. the generic attribution of triploporella neocomiensis radoičić was first questioned by granier (1988). he disputed its attribution to triploporella and ascribed it formally (though questionably) to the genus pseudoclypeina as pseudoclypeina? neocomiensis radoičić, 1963 n. comb., based on the similarity of its morphology with that of pseudoclypeina crnogorica radoičić, but without detailed discussion. granier & delofre (1993), however, did not comment on its generic status and thus retained its original name. this possible abandoning of granier’s opinion (1988) and following emendation of the generic diagnosis of selliporella (barattolo et al., 1992) probably prompted further re-investigation of the generic attribution of triploporella neocomiensis. thus yilmaz (1999), on the basis of the similarity of its morphological characteristics with the emended diagnosis of the genus selliporella, mentioned it, informally, under the name selliporella cf. neocomiensis radoičić. similarly, it will be informally ascribed to selliporella by săsăran & bucur (2001). bucur & săsăran (2003) compared the emended diagnosis of the genus selliporella with morphological characteristics of triploporella neocomiensis radoičić and proposed to be included into the genus selliporella, introducing it, formally, as selliporella neocomiensis (radoičić, 1975 non 1963) n. comb. in this comparison bucur & săsăran (2003) accept the trichophorous type of laterals as the main diagnostic feature defining its assignment to the genus selliporella, referring mainly to the reconstruction of the branches in radoičić (1963, fig. 1), which, however, cannot be accepted as an accurate representation of the illustrated sections. examining the illustrated sections of both the species originally described as triploporella neocomiensis and the identical diplopora johnsoni does not enable a decisive conclusion to be reached on the trichophorous type of secondary laterals, because their distal ends are not preserved in a single one of the rather numerous illustrated sections (radoičić, 1963, pls. 15; praturlon, 1964, figs. 12-16; jaffrezo, 1974, pl. i, fig. 4, pl. ii, figs. 11-12; luperto-sinni & masse, 1986, pl. 3, figs. 4-5; mancinelli, 1992, pl. ii, figs. 8-10; luperto-sinni & masse, 1993, pl. 1, figs. 9-10). though in the description of diplopora johnsoni the author mentions long, thin (i.e., trichophorous) laterals, he later wrote that they sometimes present distally a sharp widening, continuing into thin assimilatory filaments. also, the existence of trichophorous type secondaries cannot be deduced from sections illustrated in the paper by bucur & săsăran (2003, pls. i-iii), to which the authors do not refer; furthermore, the sections (pl. ii, fig. 1 top; enlarged details in the same plate, figs. 7-9), by the club-shaped primaries and the pores of the secondaries, appear very close to some sections of pseudoclypeina? crnogorica radoičić, 1972, emend radoičić, cararas & conrad, 2013. however, bucur & săsăran (2003) did not comment on the comparison between those two morphologically similar species, attributed to different genera. as the type of the secondaries (interpreted as trichophorous), though questionable, was considered to be decisive to the generic attribution, so their number in a tuft on the primary lateral, too, remained questionable. according to comparative table in bucur & săsăran (2003, table 1), the number of secondaries varies from 7 to 10. analysis of the illustrated sections in their paper suggests that the number is maybe lower (5-6) some of the published sections suggest the possibility of tertiary laterals (radoičić, 1963, pl. 1, fig. 1 topmost part). a similar situation occurs with the section figured in bucur & săsăran (2003, pl. iii, fig. 10), if it refers to the same form. the same question of the number of secondaries and the existence of tertiaries remains unanswered in the description of diplopora johnsoni praturlon. in conclusion, there are some unclear points in the descriptions of triploporella neocomiensis and diplopora johnsoni, in which some mentioned morphological characteristics seem more to reflect the authors’ impression than to be confirmed by the figured sections. all these suggest that an emended description and generic attribution are needed, more so because of our conviction of the two species being identical. we consider, on the base of the analysis of our material and the analysis of published illustrations, together with the fact that we changed the diagnosis of the genus selliporella, that the characteristics of this alga fit best to the genus pseudoclypeina radoičić (1970). bucur (2014) discussed the characteristics of the genus pseudoclypeina based on the shape of the primary branches, their biometric relationship with the secondary branches and the type of calcitization of the skeleton which is in three species assigned to the genus pseudoclypeina represented by the yellowish fibrous calcite (p. cirici, p. farinacciae, and p. distomensis). as for the species p. crnogorica, the bucur (2014) thinks that is most likely to be affiliated to selliporella, based on the similarity to s. neocomiensis. we think that, beside other features, the shape of the primary branches of the investigated species is coherent with that of the genus pseudoclypeina and is analogues to that of the type species p. cirici. a variety of branch shapes can often be seen in species of same genera (eg in the genus dissocladella and palaeodasycladus). as regards the calcitization of the skeleton, conrad & varol (1990) showed that it can be different in species of the same genus (eg the genera of clypeina and salpingoporella). berger et al. (2003) showed, based on genetic research, that the genus acicularia, by then distinct from the genus acetabularia by the type of calcification, is genetically identical to it and thus represents a synonym. all this excludes the type of calcitization as a reliable generic characteristic, although it may serve at the species level. pseudoclypeina johnsoni (praturlon) n. comb. pls. xvii –xix selected synonymy 1963 triploporella neocomiensis n. sp. – radoičić, 159-173, pls. 1-5; syntypes: pl. i, fig. 1; pl. ii, figs. 1-2; pl. iii, 42 1964 diplopora johnsoni n. sp. – praturlon, 179-182, figs. 12-26 1972 triploporella neocomiensis radoičić – fenninger & holzer, 123, pl. 18, fig. 2 1972 triploporella cf. neocomiensis radoičić – fourcade et al., 235, pl. 2, figs. 1-4 1974 triploporella neocomiensis radoičić – jaffrezo, 2830, pl. ii, figs. 11-12 1975 triploporella neocomiensis radoičić – radoičić, 277; lectotype: radoičić, 1963, pl. i, fig. 1 1986 triploporella neocomiensis radoičić – lupertosinni & masse, 37, 41, pl. 3, figs. 4-5 g eo lo gi a c ro at ic a geologia croatica 70/3122 1988 pseudoclypeina? neocomiensis radoičić, 1963, n. comb. – granier, 48, pl. 41, figs. a-d 1992 diplopora johnsoni praturlon – mancinelli, pl. i, fig. 4, pl. ii, figs. 8-10 1993 triploporella neocomiensis radoičić – lupertosinni & masse, pl. 1, figs. 9-10 1999 selliporella cf. neocomiensis radoičić, 1963 – yilmaz, 91, pl. 3, fig. 50 2001 selliporella neocomiensis (radoičić) – săsăran & bucur, 197, pl. 4, figs. 1-7 2003 selliporella neocomiensis radoičić, 1975 (non 1963), n. comb. – bucur & săsăran, 57 – 66, pls. i-iii 2005a selliporella neocomiensis (radoičić) – bucur & săsăran, 31, pl. iii, figs. 2-3 and bucur & săsăran 2005b, p., fig.6j,m,n 2005b selliporella neocomiensis (radoičić) – bucur & săsăran, figs. 6j,m,n 2006 pseudoclypeina? neocomiensis (radoičić) – husinec & sokač, 421, fig. 3g, fig. 4a dimensions in mm: l = 30,74 d 2,14-3,40 d 0,82-1,60 d/d 0,320 – 0,450 h 0,14-0,46 p 0,10-0,15 p´ 0,06-0,20 l 0,18-0,24 l´ 0,40-0,50 w 6-18 (?20) w’ 5-6 (?7) w’’ ?3-4 description: a relatively large calcareous alga, with cylindrical skeleton, clearly articulated all along its length. central cavity, only seldom completely preserved, occupies 30-45% of the entire diameter. (pl. xvii, figs. 1 upper part, 3, 6; pl. xviii, figs. 1, 8; pl. xix, figs. 1, 4-5). most frequently, it is secondarily widened, owing to destruction of the probably poorly calcified proximal ends of primary laterals (pl. xvii, figs. 1 lower part, 2; pl. xviii, figs. 2-3; pl. xix, figs. 2, 7). in some sections, the central cavity has a slight widening at the level of whorls and narrowing between the whorls, which makes the inner surface gently undulating (pl. xviii fig. 5). bipartite laterals are arranged into distinctly and regularly well-spaced whorls. each whorl corresponds to one article of the skeleton, formed by the amalgamation of individual calcareous sheets of tufts of neighbouring secondary laterals from the same whorl (pl. xvii, figs. 1, 4, 6; pl. xviii, figs. 1-4, 8; pl. xix, figs. 2-4, 6). primary and secondary laterals are clearly distinguishable. the primaries, slightly inflated and approximately globular in shape, vary only negligibly (pl. xvii, figs. 5-6; pl. xviii, figs. 2, 5; pl. xix, figs. 1, 5, 7). each primary lateral bears a tuft of secondaries, which were, in sections illustrated in previous papers poorly defined, mostly interpreted as being trichophorous in shape. each bundle of secondary laterals, grown out of an individual primary lateral, consists of 5-6, possibly 7-8, individual secondaries, undoubtedly visible in deeper tangential sections, cutting through their proximal parts (pl. xvii, fig. 4; pl. xviii, figs. 2-4, 6-7; pl. xix, figs. 3, 6). starting from their initial point of growth, going distally they are slightly inclined upwards or downwards. generally of a phloiophorous shape, they slightly widen distally (pl. xvii, figs. 5-6; pl. xviii, figs. 2-3; pl. xix, figs. 1, 4, 7). in some sections, ring-like constrictions of secondaries may be visible, though indistinctly, possibly indicating their articulation (pl. xvii, figs. 5-6; pl. xviii, fig. 8; pl. xix, fig. 8). the outer ends of calcified tufts are typically eroded, thus making it impossible to gain a full insight into the distal ends of the secondaries. the large number of small pores in distal tangential sections, cutting through individual tufts (pl. xix, fig. 3; also radoičić, 1963, pl. 1, fig, 1 top; praturlon, 1964, figs. 12, 14 bottom), suggests the possible existence of tertiary laterals, yet to be undoubtedly proven. this possibility is also indicated in some of our sections, in which, in their outer marginal zone, possible traces of tertiaries can be discerned (pl. xvii, fig. 7; pl. xix, fig. 7). their origin can only be supposed by the existence of tiny tufts of short tertiaries. thus the question of tertiary laterals remains open in the focus of future investigations of this interesting alga. stratigraphic position: determination of the stratigraphic range of pseudoclypeina johnsoni (praturlon) in lower cretaceous deposits of the coastal dinarides in southern croatia is based on discoveries of associated or superposed fossil assemblages in the investigated localities on mt. dinara and on the island of mljet. on mt. dinara, at the „bravči dolac” locality, this species is accompanied by the dasyclad algae salpingoporella annulata carozzi, salpingoporella steinhauseri conrad et al., falsolikanella campanensis (azema & jaffrezo), pseudoclypeina? crnogorica radoičić, clypeina marteli emberger. among the foraminifers, varcorsella camposaurii (sartoni & crescenti), and varcorsella tenuis (velić & gušić) are the most frequent, accompanied by undetermined small foraminifers. taken as a whole, the accompanying fossil assemblage at the mt. dinara locality, together with that in both the immediately overand underlying deposits, indicates a stratigraphic age range of upper berriasian – lower valanginian. the sample from the mljet island (mlj-46) comes from a poorly fossiliferous interval, typical of continuous shallow water sedimentation on a carbonate platform. the stratigraphic position can only be intermediately defined. in the analysed column, the sample mlj-46 is situated about 30 m below the first occurrence of campanellula capuensis de castro, accompanied by rare sections of falsolikanella danilovae (radoičić) and salpingoporella genevensis (conrad); immediately upwards, the algal assemblage gets richer, with typically barremian species. because campanellula capuensis in this area is characteristic of a narrow zone (taxon-range zone, velić, 1988, 2007) transitional from the late hauterivian to the barremian and because in the interval between the mlj-46 sample and the beginning of the above mentioned zone salpingoporella annulata gradually disappears, the stratigraphic position of pseudoclypeina johnsoni on the mljet locality can be ascribed to a middle hauterivian level. acknowledgement it is our pleasure to thank most cordially our colleagues ivan galović, ivo velić, božo prtoljan and igor vlahović, for field work and collecting the copious material used in this paper. moreover, we thank ivo velić for the determination of foraminiferal assemblages and explanation of their stratigraphic ranges. thanks to ivan gušić for translation and judith mcg eologia c roatica sokač & grgasović: on the species of the genus selliporella sartoni & crescenti, 1962 from the middle jurassic ... 123 kenzie for the language review of this paper. this study was supported by the ministry of science, education and sports of the republic of croatia through projects 181-1811096-1093, 1811951126-1134, and 195-1953068-0242. we especially express our gratitude to the reviewers marc conrad and ioan i. bucur for the effort, useful corrections and suggestions which have contributed to our work. in the interest of the protection of the personal attitude of ion i. bucur we must emphasize his opposition to our opinion and arguments for the assignation of the species triploporella neocomiensis radoičić to the genus pseudoclypeina. the reviewer remains of the opinion stated in his previously published papers that we, for the reasons explained in the text, could not adopt. granier, b. & deloffre, r. (1994): inventaire critique de algues dasycladales fossiles. iio partie – les algues dasycladales du jurassique et du crétacé.– rev. paléobiol., 12/1 (1993), 19–65, genève. husinec, a. & sokač, b. (2006): early cretaceous benthic associations (foraminifera and calcareous algae) of a shallow tropical-water platform environment (mljet island, southern croatia).– cretac. res., 27/3, 418–441. doi: 10.1016/j.cretres.2005.07.008 jaffrezo, m. (1974): les algues calcaires du jurassique supérieur et du crétacé inférieur des corbières (2ème parte).– rev. micropal., 17/1, 23–32, paris. luperto-sinni, e. & masse, j.-p. (1986): données nouvelles sur la stratigraphie des calcaires de plate-forme du crétacé inférieur du gargano (italie meridionale).– riv. it. paleont. strat., 92/1, 33–66, milano. luperto-sinni, e. & masse, j.-p. (1993): the early cretaceous dasycladales from the apulia region (southern italy) : biostratigraphic distribution and paleobiogeographic significance.– in: barattolo, f., de castro, p. & parente, m. (eds). studies on fossil benthic algae. proceedings of the 5th international symposium on fossil algae (capri, 7–12 april, 1991).– boll. soc. paleont. ital., spec. vol. 1, 295–309. mancinelli, a. (1992): distribuzione delle dasicladali (alghe verdi) nei sedimenti del cretaceo inferiore in facies di piattaforma carbonatica dell appennino centro-meridionale (lazio e abruzzo).– studi geol. camerti, 12, 7–29, camerino. nikler, l. & sokač, b. (1967): fosilne dasycladaceae gornje jure velebita i sjeverozapadne velike kapele (fossil dasycladaceae from upper jurassic of the mount velebit and the nw part of the mount velika kapela).– rad jugosl. akad. znan. umjet., 345, 101–134, zagreb. nikler, l. & sokač, b. (1968): biostratigraphy of the jurassic of velebit (croatia) (biostratigrafija jure velebita).– geol. vjesnik, 21 (1967), 161–176, zagreb. praturlon, a. (1964): calcareous algae from jurassic-cretaceous limestone of central apennines (southern latium – abruzzi).– geol. romana, 3, 171–202. radoičić, r. (1963): triploporella neocomiensis spec. nov. iz slojeva valendis-otriva crne gore (triploporella neocomiensis spec. nov. des couches valanginiennes-hautiriviennes du montenegro).– vesnik, a, 21, 139–144, beograd. radoičić, r. (1965): teutloporella gallaeformis spec. nov. iz jure spoljašnjih dinarida (teutloporella gallaeformis spec. nov. du jurassique des dinarides externes).– geol. glasnik, 4, 219–226, titograd. radoičić, r. (1966): microfacies du jurassique des dinarides externes de la yougoslavie.– geologija, 9, 5–376, ljubljana. radoičić, r. (1970) deux pseudoclypéines du jurassique supérieur des dinarides yougoslaves.– rev micropal, 13/2, 115–121. radoičić, r. (1975): linoporella buseri sp. nov. from the liassic of the julian alps (a preliminary report). bull. sci. cons. acad. sci. arts rsf yougosl.– sect. a: sci. nat., techn. méd., 20, 277–278, zagreb. radoičić, r., carras, n. & conrad, m.a. (2013): pseudoclypeina? crnogorica radoičić, 1972. – stratigraphic revision and taxonomic note on a little known dasycladalean alga from montenegro.– geol. anali balkan. poluostrva, 74, 25–37, beograd. sartoni, s. & crescenti, u. (1962): ricerche biostratigrafiche nel mesozoico dell’appennino meridionale.– giorn. geol., ser. 2, 29, 162–302. săsăran, e. & bucur, i.i. (2001): upper jurassiclower crelaceous microbolites and calcareos algae from strambrk-like limestones in cheile turzii area.– in: bucur, i.i. & săsăran, e. (eds): algae and carbonate platforms in western part of romania. field-trip guidebook (4th meeting of ifaa, august 29-september 5, 2001), 191–207. cluj university press, cluj-napoca. sokač, b. (1992): two new species of calcareous algae (dasycladaceae) from the upper dogger of southern dalmatia (croatia) (dvije nove vrste vapnenačkih alga (dasycladaceae) iz gornjeg dogera južne dalmacije (hrvatska)).– geol. croatica, 45, 15–24, zagreb. doi: 10.4154/gc.1992.02 sokač, b. & velić, i. (1978): redescription of the genus selliporella (calcareous algae, dasycladaceae) (ponovni opis roda selliporella (vapnenačke alge, dasycladaceae)).– geol. vjesnik, 30/1, 225–242, zagreb. sokač, b. & velić, i. (2007): stop 9 – middle jurassic with selliporella donzellii.– in: grgasović, t. & vlahović, i. (ed.): 9th international symposium on fossil algae, field-trip guidebook and abstracts. hrvatski geološki institut, 63–67, zagreb. velić, i. (1988). lower cretaceous benthic foraminiferal biostratigraphy of the shallow water carbonates of the dinarides.– rev. paléobiol., spec. vol. 2 (benthos ’86), 467– 475. velić, i. (2005): „misterij dogera”: foraminiferske zajednice i stratigrafska raščlamba srednjojurskih naslaga u krškim dinaridima (jadranska karbonatna platforma) (benthic foraminifera assemblages and stratigraphic subdivision of the middle jurassic in karst dinarides, adriatic carbonate platform).– in: velić, i., vlahović, i. & biondić, r. (eds.): 3. hrvatski geološki kongres (3rd croatian geological congress), opatija, 2005, knjiga sažetaka (abstracts book), hrvatski geološki institut (croatian geological survey), 159–160. velić, i. (2007): stratigraphy and palaeobiogeography of the mesozoic benthic foraminifers on the adriatic carbonate platform (karst dinarides, croatia).– geol. croat., 60/1, 1–113. doi: 10.4154/gc.2007.01 yilmaz, i̇. ö. (1999): taxonomic and paleogeographic approaches to the dasyclad algae in the upper jurassic (kimmeridgian) – upper cretaceous (cenomanian) peritidal carbonates of the fele (yassıbel) area (western taurides, turkey).– turkish journ. earth sci., 8, 81–101. supplement selliporella donzellii sartoni & crescenti var. gallaeformis (radoičić) n. comb., n. var. dimensions in mm: d 3,20–5,00 d ? 1,58 p 0,24 p´ 0,40–0,52 l 0,20–0,40 l 0,80–1,20 selliporella cornutoformis n. sp. dimensions in mm: l = 19,4 d 2,40–4,20 d 0,48–1,15 d/d 0,200–0,400 d´ 0,80–1,64 d 0,45–0,98 d´/d´ 0,500–0,800 h 0,98–2,38 p 0,10–0,24 p´ 0,14–0,24 l 0,15–0,20 l 0,60–1,94 w 15–25 w´ 1–3 ?5 references barattolo, f., de castro, p. & radoičić, r. (1992): the genus selliporella sartoni & crescenti 1963 (chlorophyta, dasycladales) and its type-species.– mem. soc. geol. ital. 41(1988), 593–604, roma. bassoullet, j.-p., bernier, p., conrad, m.a., deloffre, r. & jaffrezo, m. (1978): les algues dasycladales du jurassique et du crétacé.– géobios, mémoire special 2, 330 p., lyon. berger, s., fettweiss, u., gleissberg, s., liddle, l., richter, u., sawitzky, h. & zuccarello, g. (2003): 18s rdna phylogeny and evolution of cap development in polyphysaceae (formerly acetabulariaceae; dasycladales, chlorophyta).– phycologia, 42/5, 506–561. doi: 10.2216/i0031-8884-42-5-506.1 bucur i.i. (2014): a new dasycladalean alga from the lower cretaceous of the eastern carpathians (romania): andreiella rajkae nov. gen., nov. sp..– facies, 60, 217–228. doi: 10.1007/s10347-013-0375-z bucur, i.i. & săsăran, e. (2003): selliporella neocomiensis radoićič, 1975 (non 1963), nov. comb., a lower cretaceous dasyclad alga from the tethyan realm.– acta micropal. sinica, 20, 57–66. bucur, i.i. & săsăran, e. (2005a): micropaleontological assemblages from the upper jurassic-lower creataceous deposits of trascău mountains and their biostratigraphic significance.– acta pal. roman., 5, 27–38. bucur, i.i. & săsăran, e. (2005b): relationship between algae and environment: an early cretaceous case study, trascău mountains, romania.– facies, 51, 274–286. doi: 10.1007/s10347-005-0001-9 carras, n., conrad, m.a. & radoičić, r. (2006): salpingoporella, a common genus of mesozoic dasycladales (calcareous green algae).– revue de paléobiologie, 25/2, 457–517, genève. conrad, m.a. & varol, b. (1990): cylindroporella taurica n.sp., urges to rewiew different patterns of calcification in the mesozoic dasycladales (green algea).– arch. sci. geneve, 43, 193–214. de castro, p. (1997): an approach to thin-section study of fossil dasycladales (introduzione allo studio in sezione sottile delle dasicladali fossili).– quad. accad. pontaniana napoli, 22, 261 p. granier, b. (1988): algues chlorophyceae du jurassique terminal et du crétacé inférieur en alicante.– mediterranea, serie est. geol., 5 (1986), 5–96, alicante. g eo lo gi a c ro at ic a geologia croatica 70/3124 plate i 1–9 selliporella donzellii sartoni & crescenti var. donzellii (basal part of the thallus). 1,3,5 oblique-tangential sections – demonstrating the basal part of the thallus with undivided piriferous laterals. slides: fig. 1, 0-79/1; fig. 3, 0-79/216; fig. 5, 0-79/185, x22. 2 part of a tangential section – demonstrating distally individualized sheets of undivided laterals. slide: 0-79/75, x22. 4 longitudinal section. slide: 0-79/297, x22 6 longitudinal section – demonstrates the lower part of the thallus with a transition from undivided to divided laterals. the gradual increase in the outer diameter (transition to claviform thallus, complete central cavity in the lower part and secondary extended in the upper part). slide: 0-79/61, x12,5. 7–9 oblique sections – undivided piriferous laterals, with differently inclined growth and variable diameter. slides: fig. 7, 0-79/75; fig. 8, 0-79/79; fig. 9, 0-79/38, x22. g eologia c roatica g eo lo gi a c ro at ic a geologia croatica 70/3126 plate ii 1–9 selliporella donzellii sartoni & crescenti var. donzellii (basal part of the thallus). 1 longitudinal-tangential section. slide: 0-79/165, x22. 2–9 oblique and transverse-oblique sections. fig. 6a, selliporella donzellii sartoni & crescenti var. gallaeformis (radoičić). slides: fig. 2, 0-79/90, x22; fig. 3, 0-79/29, x34; fig. 4, 0-79/202, x22; fig. 5,0-79/185, x14; fig. 6, 0-79/125, x14; fig. 7, 0-79/94, x22; fig. 8, 0-79/150, x22; fig. 9, 0-79/26, x22 g eologia c roatica g eo lo gi a c ro at ic a geologia croatica 70/3128 plate iii 1–14 selliporella donzellii sartoni & crescenti var. donzellii (basal part of the thallus). 13a selliporella donzellii sartoni & crescenti var. gallaeformis (radoičić) n. comb., n. var. 1–2 transverse sections – sections of undivided laterals with distally individualized sheets. slides: fig. 1, 0-79/72, x34; fig. 2, 0-79/73; x34. 3 transverse-oblique section – demonstrates a section of three successive whorls of undivided laterals with distally individualized sheets. slides: 0-79/86, x22. 4–5 oblique sections – undivided laterals with a more or less pronounced piriferous shape. slides: fig. 4, 0-79/52, x34; fig. 5, 0-79/15, x22. 6–10 transverse sections – demonstrateing a variable number of laterals in the whorl. slides: fig. 6, 0-79/60, x22; fig. 7, 0-79/29, x34; fig. 8, 0-79/26, x25; fig. 9, 0-79/57, x25; fig. 10, 0-79/186, x25. 11 tangential section of the proximal and distal parts of whorls of undivided laterals. slide: 0-79/59, x12,5. 12–14 different sections of lower and upper parts of the thallus with undivided and divided laterals. slides: fig. 12, 0-79/79; fig. 13, 0-79/197; fig. 14, 0-79/26; x12,5. g eologia c roatica g eo lo gi a c ro at ic a geologia croatica 70/3130 plate iv 1–11 selliporella donzellii sartoni & crescenti var. donzellii 1 longitudinal section demonstrates a transition from the lower part of the thallus with undivided laterals to the upper part with divided laterals, showing an evident increase in the height of articles. slide: 0-79/112, x17 2 oblique section demonstrates a part of the thallus with a transition from the whorls with undivided laterals to the whorls with divided laterals. slide: 0-79/1, x22 3–6 more or less oblique sections of the middle part of the thallus with poorly visible primary laterals of tubular shape or slightly inflated proximally. secondary laterals approximately equidimensional. slides: fig. 3, 0-79/24; fig. 4, 0-79/214; fig. 5, 0-79/91; fig. 6, 0-79/206; x12,5 8 oblique-longitudinal section demonstrates the transition from the poorly developed primary laterals of the complete central cavity in the visibly swollen laterals of secondary extended central cavity. slide: 0-79/22; x12,5 7,9–11 transverse sections of the middle part of the thallus with poorly developed primary laterals of the complete central cavity. slides: fig. 7, 0-79/172; fig. 9, 0-79/70; fig. 10, 0–79/150; fig. 11, 0-79/214; x12,5 g eologia c roatica g eo lo gi a c ro at ic a geologia croatica 70/3132 plate v 1–6 selliporella donzellii sartoni & crescenti var. donzellii 1 longitudinal-slightly oblique section. lower part of the thallus with undivided laterals of the complete central cavity give rise to the upper part with proximally connected large primary laterals of secondary extended central cavity. slides: 0-9/65, x12,5. 2 longitudinal-oblique section demonstrates a transition to a slightly claviform shape with enlargement of the primary laterals in the upper part through proximal intercommunication of neighbouring laterals alongside a secondary extension of the central cavity. slide: 0-79/90, x17. 3 oblique section. rare occurrence of branching of secondary laterals – arrow. slide: 0-79/208, x22. 4 transverse, slightly oblique section. slide: 0-79/141, x12,5 5 tangential-longitudinal section. pronounced articulation of the lower part of the thallus making the transition to the upper part with divided large primary laterals and reduced annulation of the thallus. slide: 0-79/106. x14. 6 oblique section. oblique irregular primary laterals with proximally partly visible intercommunication. slide: 0-79/85, x12,5. g eologia c roatica g eo lo gi a c ro at ic a geologia croatica 70/3134 plate vi 1–8 selliporella donzellii sartoni & crescenti. var. donzellii 1 tangential-oblique section. the central part of the image shows the lateral compression of the primary laterals. slide: 0-79/89, x17. 2 oblique-tangential section. relatively regularly inflated primary laterals. slide: 0-79/190, x14. 3,5 oblique sections. slides: fig. 3, 0-79/73, x14; fig. 5, 0-79/35, x12,5 4,7 transverse sections. slides: fig. 4, 0-79/33; fig. 7, 0-79/47, x12,5 6 longitudinal section. transition from cylindrical to a slightly claviform part of the thallium with pronounced enlargement of the primary and secondary laterals. slide: 0-79/115, x14. 8 oblique-tangential section. the transition from the highly articulated part of the thallus to the part of visible but reduced annulation. slides: 0-79/199, x12,5. g eologia c roatica g eo lo gi a c ro at ic a geologia croatica 70/3136 plate vii 1–7 selliporella donzellii sartoni & crescenti var. donzellii 1–2 tangential-oblique sections. in the lower part of the pictures, part of the preserved articulation, reduced annulation and outer fissuring of the skeleton resulting from the individualization of the primary and secondary laterals can be observed. in the lower part of the pictures, the enlargement of the primary and secondary laterals is visible. slides: fig. 1, 0-79/201, x22; fig. 2, 0-79/30, x17. 3 longitudinal-tangential section. enlargement of laterals with emphasized intercommunication of the primary laterals of adjacent whorls. slide: 0-79/192, x22. 4 transverse section. in the central cavity of s. donzellii is transverse section of salpingoporella croatica sokač. slide: 0-79/210, x17. 5 longitudinal section. a complete central cavity with well-preserved squatty primary laterals. slide: 0-79/94, x22. 6 tangential section. in the lower part of the thallus, articulation is still apparent, passing to the upper part to reduced annulation indicated by horizontal fissures between adjacent whorls. slide: 0-79/115. 7 tangential section. a well-accentuated annulation between the articles of neighbouring whorls. slide: fig. 7, 0-79/121, x12,5. g eologia c roatica g eo lo gi a c ro at ic a geologia croatica 70/3138 plate viii 1–9 selliporella donzellii sartoni & crescenti var. donzellii 1 oblique section. an example of the articulation of part of the skeleton. slide: 0-79/174, x22. 2–3 oblique sections of a clearly marked central cavity with well-preserved primary laterals. slides: 2,0-79/188, x14; fig. 3, 0-79/195, x17. 4 oblique-transverse and transverse section. slide: 0-79/63, x17 5 oblique sections. a fragment of salpingoporella croatica sokač on the right. slide: 0-79/182, x14. 6 different sections of both varieties of the species selliporella donzellii. slide: 0-79/175, x12,5. 7 transverse, slightly oblique section with a clearly marked central cavity. slide: 0-79/192, x17. 8 tangential section. the articulated part of the skeleton passes into the part of the induced annulation. slide: 0-79/209, x12,5. 9 tangential section with fissured outer surface and the separation of envelopes of pairs of secondary laterals. slide: 0-79/134, x12,5. g eologia c roatica g eo lo gi a c ro at ic a geologia croatica 70/3140 plate ix 1–4 selliporella donzellii sartoni & crescenti var. donzelli 1 longitudinal section. slide: 0-79/113, x14 2 tangential section. slide: 0-79/183, x14 3 oblique section. slide: 0-79/99, x14 4 oblique section. slide: 0-79/42, x12,5 g eologia c roatica g eo lo gi a c ro at ic a geologia croatica 70/3142 plate x 1–9 selliporella donzellii sartoni & crescenti var. gallaeformis (radoičić) n. comb., n. var. 1–2 oblique sections – demonstrating extremely large secondary laterals, in fig. 2 of a pronounced piriferous shape. slides: fig. 1,0-79/173; fig. 2, 0-79/125, x17. 3 oblique-tangential section. extremely large secondary laterals. slide: 0-79/163, x17. 4–6 oblique sections – demonstrate very large irregular secondary laterals, in fig. 6 partially clearly piriform. slides: fig. 4, 0-79/182, x17; fig. 5, 0-79/197, x22; fig. 6, 0-79/177, x14. 7–8 oblique sections. in the pores of very large secondary laterals, the weakly visible accumulation of cysts can be observed. slides: fig. 7, 0-79/183; fig. 8, 0-79/123, x17. 9 transverse section. slide: 0-79/156, x14. g eologia c roatica g eo lo gi a c ro at ic a geologia croatica 70/3144 plate xi 1–9 selliporella donzellii sartoni & crescenti var. gallaeformis (radoičić) n. comb., n. var. 1,3 oblique sections demonstrate large, partly very irregular, secondary laterals. the secondary expanded central cavity is the result of the destruction of the primary laterals. slides: fig. 1, 0-79/162, x14; fig. 3, 0-79/122, x17. 2 longitudinal-tangential section. slide: 0-79/170, x14. 4–6 tangential sections demonstrate various types of pores of secondary laterals, round, polygonal, irregular in fig. 6 and deformed as a result of reciprocal pressing of adjacent laterals. in the pores of the cross section in fig. 5, individual cysts can be observed. slides: fig. 4, 0-79/56, fig. 5, 0-79/144; fig. 6, 0-79/164, x22. 7–9 oblique sections. in the sections of fig. 7 and 9, the large primary laterals have been partly preserved with noticeable intercommunication. slides: fig. 7, 0-79/156; fig. 8, 0-79/120, fig. 9, 0-79/156, x17. g eologia c roatica g eo lo gi a c ro at ic a geologia croatica 70/3146 plate xii 1–10 selliporella donzellii sartoni & crescenti var. gallaeformis (radoičić) n. comb., n. var. 1 longitudinal section. secondary laterals of bagged piriform shape. slide: ppb-125, x12,5. 2 tangential section. visible deformed pores of secondary laterals. slide: 0-79/147, x17. 3,7 oblique sections. in fig. 7 partly preserved primary laterals of visible intercommunication slides: fig. 3, 0-79/100, fig. 7, 0-79/120, x17. 4–5,8 approximate cross-sections. sections show different shaped secondary laterals. in fig. 5, the large primary laterals of visible intercommunication are preserved. fig. 9 demonstrates the section of the preserved outer part of the skeleton – the primary and proximal parts of the secondary laterals are destroyed. slides: fig. 4, 0-79/169, x22; fig. 5, 0-79/186, x17; fig. 8, 0-79/36, x14. 6 cross-oblique section with only the preserved distal part of the calcareous envelope. slide: 0-79/56, x17. 9–10 details of sections. arrow – a cluster of cysts in common envelopes. slides: fig. 9, 0-79/180; fig. 10, 0-79/183, x40. g eologia c roatica g eo lo gi a c ro at ic a geologia croatica 70/3148 plate xiii 1–9 selliporella cornutuformis n. sp. 1 longitudinal-tangential section. slightly claviform thallus with noticeable widening and destruction of the central cavity. undivided pirifer laterals in the basal part with short segments which are developed upwards into dividing laterals, with an increase in the number of dense and differently directed secondary laterals with a significant increase in the height of the segments. slide: ppb-125, x12,5. 2 longitudinal section. slide: kob-372/10, x12,5. 3 oblique-tangential section. in the higher part of the cross-section, the number of pores in each segment suggests 3-4 secondary laterals. slide: sb-8b/20, x12,5. 4–9 oblique sections. slides: fig. 4, sb-8b(9, fig. 5; sb-8b/8; fig. 6, sb-8c; fig. 7, ko13-372/3; fig. 8, sb-8b/18; fig. 9, sb-8b/17. figs. 4-6 demonstrating different directional growth of a larger number of secondary laterals (3-4), x12,5 g eologia c roatica g eo lo gi a c ro at ic a geologia croatica 70/3150 plate xiv 1–9 selliporella cornutuformis n. sp. 1 tangenial-longitudinal section. the number of pores in individual segments suggests a greater number of secondary laterals as a consequence of the higher segments. slide: kob.372/3. 2 longitudinal, slightly oblique section (holotype). it demonstrates the slight widening and narrowing of the central cavity and the greater distance of adjacent whorls. the entrance pore of the primary lateral is at the level of the central cavity narrowing. in the upper part of the section are 3-4 secondary laterals. slide: sb-8b/12. 3,6–7,9 transverse sections. the sections are at different segments levels, each at approximately the level of the entrance pores of the primary laterals. the sections demonstrate distal individualization of secondary laterals and their spiny shape. slides: fig. 3, sb-813/12; fig. 6, sb-8b/14; fig. 7, sb-813/15; fig. 9, sb-8b/9. 4 oblique section. slide: sb-8b/20 5 longitudinal section. at the level of narrowing, the small entrance pore of the primary lateral slide: sb-8b/4. 8 tangential section of a segment. grouped pores suggest up to 5 secondary laterals. slide: kob-372/14. g eologia c roatica g eo lo gi a c ro at ic a geologia croatica 70/3152 plate xv 1–14 selliporella cornutuformis n. sp. 1–2 tangential-oblique sections. fig. 1, arrow – a small output pore of the primary lateral. slides: fig. 1, ppb-125; fig. 2, kob-372, x12,5. 3–4,6 oblique sections. the comparison of these cross sections shows differentiated and differently directed secondary laterals. figure 6, arrow – mildly inflated primary lateral. slides: fig. 3, sb-8c/1; fig. 4, sb-8c/2; fig. 6, sb-8c, x12,5. 5,7–8 longitudinal sections. figs. 7-8 demonstrate the basal part of the thallus with undivided pirifer laterals. in both instances the spreading and narrowing of the central cavity is present. slides: fig. 5; kob-372/31; fig. 7; bv-52/3; fig. 8, ppb-125/4, x12,5. 9–11 transverse sections. the distal individualization of the secondary laterals in the shape of the spine is clearly visible. slides: fig. 9, sb-8c/1; fig. 10, ppb-125; fig. 11, ppb-125/3, x12,5. 12 tangential section of a segment. the section points to, or suggests, a larger number of secondary laterals. slide: sb-8b/1, x12,5. 13 transverse, slightly oblique section. slide: sb-8c/1, x12,5. 14 cross section of part of the thallus between whorls. calcareous envelope is perforated by a vertical tubule of unknown origin and function. slide: sb-8b/5, x12,5. g eologia c roatica g eo lo gi a c ro at ic a geologia croatica 70/3154 plate xvi 1–11 selliporella cornutuformis n. sp. 1 tangential-oblique section. slide: kob-372/5, x12,5. 2–4 longitudinal-tangential section. slides: fig. 2, kob-372/4;fig. 3–4, kob-372/39, x12,5. 5–6 longitudinal section of two segments. in fig. 5 the differently directed growth of the secondary laterals and tuber-like primary lateral (arrow) is clearly visible. slides: fig. 5, sb-8c/3; fig. 6, kob-372/23, x12,5. 7–8 longitudinal sections demonstrate the sections of the thallus of a different stage of growth. slides: fig. 7, kob-372/16; fig. 8, ppb-125/2, x12,5. 9–11 longitudinal, slightly oblique sections demonstrate different diameters of the secondary laterals. slides: fig. 9 sb-8b/21; fig. 10, kob-37/38, fig. 11, sb-8b/18, x12,5 g eologia c roatica g eo lo gi a c ro at ic a geologia croatica 70/3156 plate xvii 1–7 pseudoclypeina johnsoni (praturlon) n. comb. 1 longitudinal-oblique, partly tangential section. slide: mlj-46, x7,3 2–3 oblique sections. slides: fig. 2, mlj-46/22, fig. 3, mlj-46/21, x20,4 4 tangential-oblique section. in the tangential section of the proximal part of the secondary laterals their number is 5-6. slide: mlj-46/1, x25. 5 transverse section. poorly visible phloiophorous shape and articulation of secondary laterals. slide: mlj-46/4, x20,4. 6 oblique section. poorly visible phloiophorous shape and articulation of secondary laterals. slide: mlj-46/1, x25. 7 a fragment of a transverse section. in the edge section, an enlarged number of small pores is a possible indication of tertiary laterals. slide: mlj-46/25, x25. g eologia c roatica g eo lo gi a c ro at ic a geologia croatica 70/3158 plate xviii 1–8 pseudoclypeina johnsoni (praturlon) n. comb. 1 oblique-tangential section. slide: mlj-46/2, x13 2 tangential-oblique section. clearly visible phloiophorous shape of the secondary laterals. slide: di-031a/1, x13 3 oblique section. slide: mlj-46/2, x13. 4 tangential-oblique section. in the tangential section part there are isolated bundles of secondary laterals of adjacent articles. the number of secondary laterals is 6,?7. slide: di-031a/4, x25. 5 longitudinal section. the slight waviness of the central cavity with the incisions at the level of the primary laterals is visible. slide: di-031a, x25. 6–7 fragments of tangential sections of isolated bundles of adjacent articles. the number of pores of secondary lateral branches in the individual bundles is 6.slides: fig. 6, di-031a/3; fig. 7, di-031a/4, x25. 8 cross section of two adjacent articles. see the articulation of secondary lateral – arrow. slide: mlj-46/18, x20,4 g eologia c roatica g eo lo gi a c ro at ic a geologia croatica 70/3160 plate xix 1–10 pseudoclypeina johnsoni (praturlon) n. comb. 1 oblique section. irregularly inflated primary laterals are visible. slide: mlj-46/3, x20,4. 2 oblique section. slide: di-031a/7, x25 3 tangential section. slide: di-2a, x13 4 oblique section. in the outer edge is the indication of the tertiary lateral – arrow. slide: mlj-46/17, x20,4. 5 oblique section. irregularly inflated primary laterals are visible. slide: mlj-46/5, x20,4. 6 tangential-oblique section. slide: mlj-46, x15 7 slightly oblique section. clearly visible phloiophorous shape of the secondary laterals and the indications of the tertiary laterals is expresse – arrow. slide: mlj-46/3, x20,4. 8 slightly oblique section. see the articulation of secondary lateral – arrow.slide: mlj-46/5, x20,4. 9 oblique section. slide: mlj-46/3, x13. 10 transverse section. slide: di-031b/5, x13 g eologia c roatica www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2025 | 78/3 | 257–265 | 4 figs. | 1. introduction the external (outer) dinarides can be considered as the de­ tached and highly deformed upper crust of the central adriatic microplate (adria) during its subduction to the ne (korbar, 2009 and references therein). possible multiphase reactivation of triassic rifting structures (lineaments), formed during sepa­ ration of adria from gondwana, as well as movement of adria within the western tethys (van hinsbergen et al., 2020), strongly affected mesozoic extension to cenozoic com­ pression of its central part. the process has strongly affected the stratigraphy and styles of tectonic deformations within the upper crust, and that is why the central part of the external dinarides is divided into several major tectonic (tectonostrati­ graphic) units (schmid et al., 2008; korbar, 2009; fig. 1). during the early­orogenic thin­skinned tectonic deforma­ tions, and progressive migration of the deformation front of the dinaric (alpine) orogen from the ne to the sw, sedimen­ tary successions were detached on various decollements. the inactive thrust front of the central part of the external dinar­ ides is nowadays recognized offshore, sw of the outer ne adriatic islands (fig. 1). the axial zone of the external dinar­ ides is characterized by moderate earthquakes (fig. 1) that are probably nucleated along the pre­orogenic crustal lineament that was reactivated during a late­orogenic transpressional stage (picha, 2002; korbar, 2009). tectonic transport along the zone is probably still active during the present-day escape tectonics (picha, 2002). thus, the pre­existing upper crustal structures related to the early orogenic deformations are masked during this latest stage of the geodynamic evolu­ tion of the external dinarides. conflicting tectonic interpretations of the central external dinarides tvrtko korbar1,* 1,* croatian geological survey, department of geology, sachsova 2, 10000 zagreb, croatia; (*corresponding author: tkorbar@hgi-cgs.hr) doi: 10.4154/gc.2025.17 abstract the tectonic structure and orogenic evolution of the central part of the external (outer) dinarides in croatia (northern dalmatia, velebit, and lika) has been interpreted in different, sometimes conflicting ways. one of the recent models interprets the external dinarides as a fold and thrust belt, characterized by the early orogenic thin-skinned contractional phase, followed by thick-skinned exhumation and related gravitational collapse of the thin-skinned cover. another recent model offers the same tectonic style in the first phase of the orogenesis, followed by formation of a triangle zone and low angle north directed passive roof backthrusts in the intermediate phase, and final uplift because of antiformal south directed duplex stacking and multiple thrusting in the former tectonic basement. however, despite up-to-date geological cross section analysis, the later model seems to lack field data supporting it. this paper will discuss the need for such a complex and completely new regional tectonic interpretation that requires more thorough checking of existing observations previously published in numerous local studies and maps, and meticulous redebating of earlier interpretations before they are replaced. moreover, it is concluded that the former model, reinterpreted here, combining the early-orogenic thin-skinned and late-orogenic crustal thick-skinned tectonics, seems to fit better both the seismological fault mechanism solutions and updated geological maps of the area. in the last few years, balling et al. (2021a, b, 2023) published three papers dealing with the orogenic evolution of the central part of the external dinarides, offering inter pretation of the genesis of some important tectonostratigraphic units, and a completely new model of the orogenic evolution and the tectonic structure of this complex fold­and­thrust belt. the authors used state­of­the­art structural geology software, but the input data is not supported by verifiable field mea surements. although published by a group of distinguished struc­ tu ral geologists, the complexity of the belt advocates a more systematic approach to the new outcomes. besides, since some interpretations are similar to those in the previous models, there is a need to give due credit to the previous authors. in the first paper, balling et al. (2021a) argue for mantle delamination constrained by the uplifted miocene marine terraces that the authors recognized during their trip along the eastern adriatic coastal dinarides. however, in the supple­ mental kml file of the paper there are hundreds of polygons marking "horizontal surfaces" that are supposed to be marine terraces, although there is neither evidence that any of the marked surfaces is of marine origin nor that they are of miocene age. besides, and more importantly, most of the "terraces" are not horizontal at all. maybe the surfaces seem horizontal on the scale of the eu-dem (25 m resolution and vertical accuracy of 7 m vertical), but on more detailed official topographic maps of the republic of croatia (e.g., dgu, 2023) it is clear that most of the small "horizontal surfaces" marked on the kml file of balling et al. (2021a) are neither horizontal nor flat, except for some small karst poljes, that are not terraces. however, the "terraces" are not in the focus of this paper. article history: manuscript received: july 16, 2024 revised manuscript accepted: july 29, 2025 available online: october 13, 2025 keywords: external dinarides, geological structure, various models, active faults, seismotectonics mailto:tkorbar@hgi-cgs.hr g eo lo gi a c ro at ic a 258 geologia croatica 78/3 the focus is on the papers of balling et al. (2021b, 2023) that combine state­of­the­art structural geology tools and modern terminology for reinterpretation of comprehensive published data from the official geological maps, i.e., sheets and explanatory notes of basic geological map (bgm) of former yugoslavia at the 1:100,000 scale in the region of the central external dinarides (bgm, 1965–1984), cited also in balling et al. (2021b, 2023). however, after a thorough reading of the papers, and cross­checking of the papers and maps cited in the paper, as an author of the previously published model (korbar, 2009), i felt i should add new data and the discussion to support that model, and also to point to some weak points of the latest model. namely, that was already the third paper of phillip balling and a group of the co­authors in a series in which they proposed a completely new and the most complex model of the central part of the external dinarides to date, but with unverifiable data that are supposed to document the reinterpreted elements. the model of balling et al. (2023) shows a greater com­ plexity of structural architecture than previous interpretations, but it seems that the model is not supported either in the field geological data nor in the seismological data presented in the paper itself. in the following sections the most questionable issues are addressed. 2. discussion 2.1. previous models and tectonic subdivision although there are several tectonic models for the external dinarides published during the 20th century (korbar, 2009 and references therein), in this paper i will focus only to the most recent, modern models published in scientific journals figure 1. tectonic map of the area of the central external dinarides of balling et al. (2023), showing the main faults and the earthquakes epicenters with general magnitudes and focal depth as well as focal mechanism solutions (fms). additions are in yellow: yellow lines mark the positions of the regional geophysical and geological cross-sections: 1 – šumanovac et al. (2016), 2 – korbar (2009), both discussed in the text and shown on other figures, and 3 – balling et al. (2023) that is reinterpreted on figure 4 (this paper); yellow polygon marks area shown on figure 3; yellow question mark indicates the questionable boundary between the two traditional regional tectonic units that is drawn along minor faults by schmid et al. (2020), as especially obvious on the island of cres in kvarner (compare with map of fuček et al., 2015). g eologia c roatica 259korbar et al.: conflicting tectonic interpretations of the central external dinarides during the 21st century, which include also the most important issues of the previous models. one of these is a model of korbar (2009) and another one is a model of balling et al. (2021b, 2023). balling et al. (2021b, 2023) used an overview tectonic map of schmid et al. (2020) rather than an older version that had a better fit to the local data (schmid et al., 2008). however, the former became very popular also among the other authors working in the external dinarides, although the authors of the map did not consider modern data, especially the data published during the last decade on the new lithostratigraphical maps of the republic of croatia at the 1:50,000 scale that are much more detailed than the older bgm (1965 – 1984). the bgm is the only map that covers a complete investigated territory and is thus used by balling et al. (2021b, 2023), but the published sheets of the new lithostratigraphical map at the 1:50,000 scale should be used where available. for example, the new supra-regional map of schmid et al. (2020) proposed a new boundary between the dalmatian and high karst tectonic units that is not supported by published new local maps and scientific papers. namely, in the central part of the island of cres in the kvarner area, the boundary is a local fault without such importance (fuček et al., 2015; fig. 1). moreover, it is obvious that balling et al. (2023) did not give credit to the most important issues of the orogenic evolution of the region that are proposed in the previous models: (i) stratigraphically various detachments on evaporite horizons (permian – triassic and jurassic – cretaceous transition), (ii) early­orogenic foreland propagating thin­ skinned tectonics (confirmed also by balling et al., 2023), and (iii) the general geotectonic setting of the promina basin as a wedge­top (korbar, 2009). geophysical studies based on teleseismic data (šumanovac et al., 2016; kapuralić et al., 2019), indicate crustal thickening in the area, that is also supported by gravimetry data and deep seismic profiles (prelogović et al., 1995; tari kovačić & mrinjek, 1994). this thickening is compatible with activity of crustal scale high angle transpressive faults that could be related to the major crustal ne adriatic fault and exhumation along the crest of the external dinarides (korbar, 2009; fig. 2). in the model of balling et al. (2021b, 2023), the authors do not consider these previous data and interpretations and resolve the issue proposing an antiformal stack. besides, balling et al. (2023) introduces a new terminology for distinguishing structural units in this part of the external dinarides (lower high karst and upper high karst), although chorowicz (1974, 1975) had already proposed a subdivision into inner karst and high karst. chorowicz's subdivision was harmonized and accepted for the entire area of the external dinarides in a review of korbar (2009), although the author was not fully consistent with the original names of the units, but proposed alternative names that were nevertheless compared with the traditional ones. i would like to highlight here a positive example of an acceptable reinterpretation of a traditional overall tectonic structure in the northern calcareous alps, that is constrained by a comparison of a previous and a new model that illustrate less shortening for the previously considered large scale thrusting of this well-known fold and thrust belt (fernandez et al., 2024). 2.2. reinterpretation of the data from the basic geological maps 1:100,000 – velebit fault system and "lika backthrust" some of the main input data for the presented modelling are from the reinterpreted basic geological maps 1:100,000 (bgm) that are cited in balling et al. (2023), which in the researched area are in principle very well made based on comprehensive fieldwork and the results of many local studies performed during the 20th century. however, many of the data presented on bgm sheets and accompanying explanatory notes (with references therein) were neglected by balling et al. (2023). geological boundaries mapped over any distance (if done reliably with continuous outcrop conditions or adequate constraints) have more significant regional value than a local outcrop observation (fernandez et al., 2009; stewart, 2020). it is especially true in carbonate rocks of the external dinarides. there are numerous well-defined but local fault planes visible within open outcrops in carbonate rocks in the forested area (e.g., quarries) that have only a very local significance and disappear within a few metres, thus probably bounding small blocks. therefore, the interpretation of regional­ scale geometry is much better constrained by the relationship between fault traces and relief. for example, there are many local measurements in the kvarner area of the external dinarides (korbar et al., 2020, supplementary file), that resemble tectonically important fault planes, but do not have a significance for drawing of the main faults on the geological map. the abovementioned criticism mainly refers to the reinterpretation of the important faults that were originally interpreted as steep normal faults on the bgm (see also chorowicz, 1974; korbar, 2009). however, according figure 2. simplified crustal geological section across the central external dinarides (crop of fig. 12 of šumanovac et al. (2016, coloured, black dots = hypocenters), modified with supposed active crustal transpressional faults along a supposed ne adriatic fault zone (korbar, 2009, white lines and general dextral slip, for details see text and fig. 4 in this paper). vf – velebit fault = ne adriatic fault. location is indicated on figure 1. g eo lo gi a c ro at ic a 260 geologia croatica 78/3 to balling et al. (2021b, 2023), the so-called "lika fault system" (lfs) is composed of several relatively shallowly dipping passive roof backthrust faults that are thrust top­to­ north in the hinterland (so­called the "lika backthrust"), and even further to north, as far as the plitvice fault system (pfs) or the "plitvice backthrust" (fig. 1). for the purpose of forward modelling, balling et al. (2023) use several selected field measurements (without the information about locations) to re-interpret the lfs and pfs as gently sw dipping and top­to­north directed backthrusts, but without detailed structural elaborations on the outcrops or new geological maps, although these are shown subvertical on the all sheets of the bgm (produced by various authors). the velebit fault system (vfs) seems conjugated to the lika fault (brušane fault, paklenica fault etc.) and could indeed be composed of sw dipping reverse faults (velić et al., 2014), but the fault planes are certainly very steep, which is revealed also by the rather rectilinear traces on the map, regardless of the relief cut by the faults. the steep fault planes of the vfs are also clearly visible in panoramic view, along the slopes of the central part of velebit mt. (sokač et al., 1974; fig. 3). besides, the lika fault dissects the older dinaric thrust (nappe) that encompass the bruvno dome from the north and east (bgm: šušnjar et al., 1973; chorowicz, 1974; fig. 4 of korbar, 2009). noteworthy, the inner karst nappe encompassing the bruvno dome from the north and east does not include palaeozoic clastics that are exposed only in the core of the bruvno dome and along the velebit structure – the two thick­skinned units separated by the subvertical lika fault (šušnjar et al., 1973; chorowicz, 1974; korbar, 2009). however, balling et al. (2023) reinterpreted the lika fault as a single nappe encompassing the bruvno dome also from the south, although, even according to the authors, the detachment horizons are different, i.e., the older thrust sheet (northern) was detached at lower triassic and was thrust to the south, while the younger thrust sheet (southern) includes also the palaeozoic strata and was thrust to the north. the "plitvice backthrust" or “plitvice fault system” (pfs) of balling et al. (2023; fig. 1), is also obviously a subvertical fault since its trace appears rectilinear on the regional geological maps (bgm), and thus probably belongs to the plitvice – una spring fault zone along the northern margin of the transpressional system of the ne adriatic fault zone (fig. 4). the selected measurements that are supposed to elaborate the gently inclined pfs are used as the main input data for the model of balling et al. (2023), but the locations of the measurements are not provided (neither are provided in the cited graduate student diploma). consequently, the entire modelling and final interpretation of balling et al. (2023) took place in an unusual direction, which led to an unusual interpretation, or, as the authors themselves stated, contrary to the similar systems modeled so far elsewhere in the world. 2.3. the bruvno structure another questionable structure modelled by balling et al. (2021b, 2023) is a complex duplex system of multiple thrust faults forming an antiformal stack of the bruvno dome, that is interpreted as the latest phase compressional structure responsible for the uplift of velebit mt. and its hinterland. the relative timing of the formation of the dome is also proposed by other authors (korbar, 2009), however, published data imply that this is a para-autochthonous pop-up structure (šušnjar et al., 1973; sokač et al., 1976). the bruvno duplex shown by balling et al. (2021b, 2023) consists of as many as 5 thrust faults within palaeozoic clastics, stacked one above the other, of which the structurally highest one intersects the bruvno borehole located in the central part of the dome (for position see fig. 4 of korbar, 2009; fig. 2 of balling et al. (2023); fig. 4). the fact is, instead, that there are no reported faults within the more than 3 km deep bruvno borehole, that was drilled through carboniferous and probably older clastics. such an undocumented interpretation certainly strongly contributes to the unnecessary complexity of the resulting model, which can be performed in a much simpler way. for example, korbar (2009) also considered the largescale thrusting in the first phase of the orogenesis as balling et al. (2021b, 2023) that affected only thin-skinned cretaceous and younger units within the high karst unit (lower high karst of balling et al., 2023), and triassic and younger units within the inner karst unit (upper high karst of balling figure 3. a interpreted aerial panoramic western view to the brušane anticline area (central velebit mt., compare with bgm sheet gospić (sokač et al., 1974) and fig. 6 of balling et al., 2023). note rectilinear trace (red line) of the brušane fault, one of the main faults of the vfs that is conjugated to the lika fault (indicated in the background). erosional remnants of the jelar/velebit breccia (vb) are not in contact with the brušane fault; b interpreted eastern view on dabarski kukovi (marked by a white arrow on "a") that are built of massive cenozoic jelar/velebit breccia (vb) resting unconformably(?) on top of well-bedded upper jurassic platform carbonates (black lines). note the steep brušane fault to the south (red line). g eologia c roatica 261korbar et al.: conflicting tectonic interpretations of the central external dinarides et al., 2023). however, the palaeozoic (carboniferous and permian) units were probably deformed later, during the late­ orogenic thick­skinned tectonics, responsible for the uplift of the velebit mt. core and the bruvno dome (korbar, 2009). 2.4. split – karlovac fault the regional transverse split – karlovac fault (skf) was proposed by chorowicz (1977), but there were no later papers published with the details that would characterize its character, geometry, and more detail descriptions on the most important localities. balling et al. (2021b) regarded the fault as a dextral strike-slip fault without field measurements and/or new geological maps and combined state­of­the­art structural geology tools to re­interpret the role of that still controversial regional tectonic feature in the tectonic evolution of the region (fig. 1). besides, balling et al. (2021b) offer evidence for the supposed cretaceous deposits in the footwall of plavno tectonic window by using a single photomicrograph that is determined as cretaceous foraminifera that should be the final proof of the window that is also shown on the bgm. however, the single equatorial transection of the foraminifera is an unreliable biostratigraphic element, i.e., it could be determined as the lower triassic index fossil meandrospira dinarica that is a common microfossil in the area (kochansky-devidé & pantić, 1965). moreover, my own observations (including mirko belak pers. comm., 2006), suggest that the supposed cretaceous deposits in the plavno tectonic window litho lo gically resemble lower triassic deposits, implying that the plavno need not be a tectonic window at all. balling et al. (2021b) claim that the thrusts are south directed east of the skf, while west of it there are mostly north directed backthrusts at the surface. however, according to the bgm sheets (see also herak & bahun, 1979), there are sw directed thrusts west of the skf (stražbenica, čemernica, etc., šušnjar et al., 1973; chorowicz, 1974; fig. 5 of korbar, 2009). large thrusts that include permian clastics can be found in gorski kotar (herak et al., 1961). further to the west, in southern slovenia and northern istria, there are also obvious frontal nappes of the external dinarides (korbar, 2009 and references therein; placer et al., 2010). noteworthy, the north directed low­angle and long­ traveling backthrust in the external dinarides are recognized so far only by balling et al. (2021b, 2023). 2.5. velebit/lika/jelar breccia the massive cenozoic (oligocene?) carbonate breccia that outcrops along the sw and ne slopes of velebit mt. and the lika area is traditionally referred to as the jelar deposits/ formation/breccia (bahun, 1962, 1963, 1974; herak & bahun, 1979; korbar, 2009 and references therein). in the work of balling et al. (2023) it is stated, without any evidence, that the "velebit breccia" and "lika breccia", are two different formations that crop out on the sw and ne slopes of velebit mt., respectively. however, even the data mentioned sporadically in the paper of balling et al. (2023) indicates that such a distinction is not acceptable. it is clear from the geological maps (see overview map of the synonymous velebit breccia of vlahović et al., 2012) that the breccia belt periclinally and almost continuously encompasses velebit mt. and appears in places separately in the lika area (velebit hinterland). besides, the breccia has a similar tectonostratigraphic position since it rests unconformably on top of the upper jurassic carbonates on the sw (fig. 3) as well as on the ne slopes, and has a similar composition in both these areas (vlahović et al., 2012), implying that they are probably of the same genesis (see korbar, 2009). in the case that the velebit breccia would be related to the vfs faults (fig. 6 of balling et al., 2023), the clasts in the breccia would also be from the permian and triassic rocks outcropping along the fault contact with the outcrops of upper jurassic, but that is not the case (vlahović et al., 2012). instead, the breccia belt is dissected by the vfz faults that are thus younger than the breccia, and the erosional remnants of the breccia are not consistently in contact with the brušane fault (sokač et al., 1974; fig. 3). however, there are differences in the composition of this type of breccia outcropping around velebit mt. (typical jelar/ velebit breccia), and those outcropping in the eastern lika area (upper stream of una river, bahun, 1985). thus, the composition of the widespread cenozoic breccia in the central part of the external dinarides depends on the thickness of the thin­skinned stratigraphic succession in the highly deformed hanging walls of the thin-skinned nappes formed in the first phase of the orogeny (korbar, 2009). namely, the lithoclasts probably collapsed during the secondary phase of the orogenesis, i.e., thick­skinned uplift of the whole sedimentary succession (including the palaeozoic), resulting in extension within the previously thin­skinned upper parts of the succession due to the supposed gravitational reactivation of the early­orogenic compressional detachments (korbar, 2009). if so, the extension resulted in the local deposition of large masses of collapse breccia that include older strati graphi­ cal members in eastern lika (inner karst = upper high karst of balling et al., 2023) than in the velebit mt. area (high karst = lower high karst of balling et al., 2023). in the velebit area (including lika polje), typical jelar/velebit breccia clasts originate from all stratigraphic members from the lower cretaceous to dinaric flysch, since the detachment was within the jurassic – cretaceous transition. in the eastern lika area (una spring area), where the detachment was within permian evaporites, the breccias are characterized by the older stratigraphic members in the clasts, e.g., lower triassic clastics and younger carbonates. thus, in the eastern lika the breccia could indeed be re­named, e.g., lika or una breccia, since the composition differs from the typical jelar/velebit breccia on velebit mt, although the main mechanism of the origin of both is probably the same (korbar, 2009 and references therein). nevertheless, all the cenozoic tectonic breccia mentioned above could be broadly and traditionally recognized as the jelar group. 2.6. relative timing of deformations within the "foreland" and the main crest of the external dinarides according to balling et al. (2021b, 2023) there are three main phases of the orogenic deformation along the main crest of the external dinarides: early­orogenic south directed thin­ g eo lo gi a c ro at ic a 262 geologia croatica 78/3 skinned thrusting (the same was proposed by korbar (2009), the newly proposed north­directed thin­skinned backthrust during an intermediate phase, and the latest again south directed "thick­skinned" antiformal nappe stack within the palaeozoic basement along a "triangle zone". the latest nappe stack is supposed by balling et al. (2023) to cause the uplift of the thin-skinned palaeozoic and mesozoic successions along velebit mt. and the exhumation of the bruvno dome. the latest (exhumation) phase was also suggested by korbar (2009), who proposed late­orogenic uplift accommodated by relatively steep transpressional faults, that are also responsible for the recent seismicity (see next section). although the frontal thrust of the external dinarides is situated in the adriatic sea, sw of the outer dalmatian islands (fig. 1), balling et al. (2021b, 2023) consider the islands as a foreland of the velebit structure. however, even according to their model, velebit was uplifted in the latest phase within the triangle zone. it should be emphasized that, according to the latest previous model (korbar, 2009), the thin­skinned structures of the northern dalmatian islands were also formed before the uplift of velebit mt., the complex thick-skinned figure 4. geological sections across the central part of the external dinarides of a korbar (2009, fig. 5) with an indication of the frame of "b", broken frame), and b balling et al. (2023, fig. 11), coloured in the background, and the crustal transpressional faults (thick black lines, modified after korbar, 2009). locations are indicated on figure 1. g eologia c roatica 263korbar et al.: conflicting tectonic interpretations of the central external dinarides structure along the main crest of the external dinarides. that is why the northern dalmatian islands also belong to the external dinarides, rather than to its recent foreland, as proposed by balling et al. (2021b, 2023). 2.7. discrepancy between the latest model and the seismological data the most challenging issue in the model presented by balling et al. (2023) is the discrepancy in the position of the earthquake hypocenters, and especially their focal mechanism solutions (fms), with the interpreted faults that are active in the underground of southern velebit (fig. 11 of balling et al., 2023; fig. 4). even in a tentative comparison it is clear that the main faults in the previous models overlap better with the hypocenters and the fault mechanism solutions (fms) than in the new model of balling et al. (2023). this is particularly illustrated by one of the strongest recent earthquakes (01/11/2020, m4.6), with computed fms showing clearly a relatively steep reverse slip. besides, there was an even stronger recent earthquake (ml4.8 on 11th of february 2025) in the same area with the fms showing a clear subvertical strike-slip along generally e – w or n – s trending faults deeper in the crust (pmf, 2025). this newly registered strike-slip mechanism in combination with the former predominantly oblique slip and reverse dip-slip solutions (herak, 2025), further points to the presumed transpressional active tectonic regime in the wider velebit area (korbar, 2009). comparison of the spatial position of the hypocenters with the interpreted active faults and its fms (herak, 2025) is the main test of any seismotectonic model. therefore, due to the apparent inconsistency of these two elements, the model of balling et al. (2023) is not reliable, and the fms has a better fit to the deeper and steeper crustal transpressional faults of korbar (2009) than to the shallow thrusts of the so-called velebit – bruvno triangle zone proposed by balling et al. (2023). namely, it seems that major crustal thick­skinned steep reverse (transpressional) faults, striking nw – se along the main crest of the external dinarides, fit well with the modern hypocenters and fms (fig. 4). thus, active faulting is probably related to the still active late­ orogenic transpression that is responsible for the exhumation and uplift of the main crest of the external dinarides, rather than multiple low-angle thrusting within the palaeozoic basement. a similar mechanism is proposed in the nw zagros (mouthereau et al., 2012), but a more detailed comparison is beyond the scope of this paper but should be performed in future analyses. 2.8. updated tectonic model possibly still active and deeply penetrating transpressional faults striking along the velebit mt. were originally proposed by korbar (2009) and are reinterpreted in this paper according to the new idea of blind active faulting in the sw front of the ne adriatic fault zone, since they probably do not dissect the thin-skinned early-orogenic cover (fig. 4). the hypocentral depths between 8 and more than 20 km, as well as its distribution, support the interpretation. the focal mechanisms (fms) imply that the faults are mostly relatively steep, reverse, oblique and strike-slip, thus they probably accommodated transpression within the upper crust. however, there must be lower crustal or even a deeper driver of the upper crustal dynamics mentioned above, and that is why the ne adriatic fault, separating the dinaric and adriatic segments of the adria, is proposed (korbar, 2009). the active faults are probably blind sw of velebit mt. since they are not shown on the geological maps. thus, the thin­skinned cover probably gravitationally glided down (stripped) along the former low­angle compressional detachments during the late-orogenic uplift of velebit mt. in the first phase of the uplift, the gravitational extension on the flanks of the uplifting velebit structure (thick arrows on fig. 4a) could result in the gravitational collapses within the thinskinned cover and therefore deposition of the late­orogenic jelar/velebit breccia (korbar, 2009) that encompasses the velebit mt. central ridge (vlahović et al., 2012). however, some branches of the late­orogenic and possibly still active transpressional faults dissect the breccia belt (sokač et al., 1974; fig. 3), while the thin-skinned orogenic cover is completely eroded along the central crest of the mountain, along with its exhumed tectonic basement (fig. 4b). there are mapped active dextral strike­slip seismogenic faults in the nw part of the external dinarides, striking generally nw – se, that are referred to the dinaric fault system (moulin et al., 2016). the active faults are characterized by subvertical fault planes along a crustal fault zone (vičič et al., 2019) that obviously dissect the thinskinned cover and continue further to the se in the kvarner area (korbar et al., 2020). the fault zone could be equivalent to the ne adriatic fault zone of korbar (2009), that also strikes along the velebit mt. and its wider hinterland (fig. 4). it is still not clear why the seismicity is weak along the velebit mt. (herak, 2025). however, some of the active faults within such a wide zone may be currently locked (vičić et al., 2019). interestingly, the ne adriatic fault zone resembles the active and slowly-deforming wide shear zone of eastern california (garvue et al., 2024). if so, velebit mt. and other positive flower structures along the zone could be formed along the complex system of the active strike­slip faults and several restraining bends. the restraining bends could be formed at the crossing points of the main pre­orogenic crustal faults that were not all reactivated in the first compressional phase of the dinaric orogenesis, but probably completely covered by the thin­skinned early­orogenic highly deformed topmost sedimentary successions (korbar, 2009; balling et al., 2021b, 2023). the subvertical active dextral strike­slip faults are well documented in the nw part of the external dinarides and could also have a continuation along velebit mt. and its wider hinterland. however, such faults are not mapped on the surface, but some of the active faults could be blind, since they do not dissect everywhere the thin­skinned tectonic cover. moreover, recent seismicity, in combination with the former predominantly reverse oblique-slip mechanisms, also imply an overall transpressional active tectonic regime in the central external dinarides, but further targeted multidisciplinary research should be performed. g eo lo gi a c ro at ic a 264 geologia croatica 78/3 conclusion balling et al. (2021b, 2023) deal with the orogenic evolution of the central part of the external dinarides, offering a complex new model and the tectonic structure of the area that combine state­of­the­art structural geology tools and modern termi no­ logy. however, the new model is constrained neither by com­ prehensive data from the official geological maps in the region, nor with the new data and necessary local structural geology studies that could contribute to the elucidation of the still not completely understood tectonic evolution in the region. balling et al. (2023) introduces a new terminology for distinguishing structural units in this part of the external dinarides, although previous authors already proposed almost the same subdivision that was harmonized and proposed previously for the entire area of the external dinarides (korbar, 2009 and references therein). the so­called lika fault and the other faults of the velebit fault system (vfs) were originally interpreted as subvertical normal faults (šušnjar et al., 1973; sokač et al., 1974) but are re­interpreted by balling et al. (2023) as low angle backthrusts, although the faults have rather long rectilinear routes, regardless of the relief cut by the faults. besides, the lika fault dissects the older dinaric low­angle thrusts (nappes) that encompass the bruvno dome from the north and east (chorowicz, 1974; korbar, 2009). balling et al. (2023) reinterpret and divide an important tectonostratigraphic unit in velebit mt. and lika polje, i.e., the jelar/velebit breccia. however, the breccia has a similar stratigraphy and composition, regardless of the location on the northern or southern slopes of the huge but dissected velebit anticline, and therefore it likely has the same genesis. korbar (2009) proposes that the late­orogenic uplift (exhumation) resulted by gravitational reactivation of the thin­skinned detachment (stripping), related collapses within the thin­ skinned cover, and the deposition of the late­orogenic breccia above the detachment. the bruvno dome is interpreted by balling et al. (2023) as the latest phase compressional structure of the supposed velebit – bruvno triangle zone that consists of as many as five low-angle thrust faults within the palaeozoic basement of the earlier thin­skinned cover, although there are no thrusts reported from the more than 3 km deep bruvno well. thus, the palaeozoic (carboniferous and permian) units were rather deformed along steeply dipping and deeply penetrating crustal faults reactivated during the late­orogenic thick­skinned tectonics, responsible for the uplift of the velebit mt. core and the bruvno dome. the most problematic issue in the model presented by balling et al. (2023) is the discrepancy in the spatial position of the earthquake hypocenters, and especially their focal mechanism solutions (fms), with the interpreted low-angle faults. an updated older model (korbar, 2009) offers steeper faults that fit better with the hypocenters and fms. however, the supposedly still active crustal transpressional faults along the main crest of the external dinarides probably did not dissect the early­orogenic thin­skinned cover along the sw foothills of the huge velebit anticline, and thus are probably mostly blind and active below the thin-skinned cover that was “stripped” from the main ridge of velebit mt. acknowledgment i thank the late professor ivan gušić for encouraging me to write the manuscript. very constructive and com pre hensive reviews of dr. oscar fernandez (university of vienna) and the associated editor silvia mittempergher are greatly acknowledged, as well as a review of an anonymous reviewer. references bahun, s. (1962): vapnenci promina-naslaga u području kruščice u lici [limestones in the promina deposits of the territory of kruščica in lika].– geološki vjesnik, 15, 101–107. bahun, s. (1963): geološki odnosi okolice donjeg pazarišta u lici (trijas i tercijarne jelar-naslage) [geological relations of the surroundings of donje pazarište in lika].– geološki vjesnik, 16, 161–171. bahun, s. (1974): tektogeneza velebita i postanak jelar-naslaga [the tectogenesis of mt. velebit and the formation of jelar-deposits].– geološki vje­ snik, 27, 35–51. bahun, s. (1985): trijaske naslage i jelar-formacija u dolini une između srba i brotnje (hrvatska) [triassic deposits and jelar formation in the una valley between srb and brotnja (croatia)].– geološki vjesnik, 38, 21–30. balling, p., grützner, c., tomljenović, b., spakman, w. & ustaszewski, k. (2021a): post-collisional mantle delamination in the dinarides implied from staircases of oligo-miocene uplifted marine terraces.– scientific reports, 11/1, 2685. https://doi.org/10.1038/s41598021-81561-5 balling, p., tomljenović, b., schmid, s.m. & ustaszewski, k. (2021b): contrasting along-strike deformation styles in the central exter­ nal dinarides assessed by balanced cross­sections: implications for the tectonic evolution of its paleogene flexural foreland basin system.– global and planetary change, 205, 103587. http://doi.org/10.1016/j.gloplac­ ha.2021.103587 balling, p., tomljenović, b., herak, m. & ustaszewski, k. (2023): impact of mechanical stratigraphy on deformation style and dis­ tribution of seismicity in the central external dinarides: a 2d forward kinematic modelling study.– swiss journal of geoscience, 116, 7. https:// doi.org/10.1186/s00015-023-00437-0 chorowicz, j. (1974): le chevauchement du velebit (croatie, yougoslavie).– bulletin de la société géologique de france, 7/16, 74–85. chorowicz, j. (1975): le devenir de la zone de budva vers le nord-ouest de la yougoslavie.– bulletin de la société géologique de france, 7/17, 699–709. chorowicz j. (1977): étude géologique des dinarides le long de la structure transversal split-karlovac.– thèse univ. pierre et marie curie, paris, 322 p. fernandez, o., jones, s., armstrong, n., johnson, g., rava­ glia, a. & muñoz, j.a. (2009): automated tools within workflows for 3d structural construction from surface and subsurface data.– geoinfor­ matica, 13, 291–304. https://doi.org/10.1007/s10707-008-0059-y fernandez, o., ortner, h., sanders, d., grasemann, b. & leitner, t. (2024): salt-rich versus salt-poor structural scenarios in the central northern calcareous alps: implications for the hallstatt facies and early alpine tectonic evolution (eastern alps, austria).– international journal of earth sciences, 113, 245–283. https://doi.org/10.1007/s00531023-02377-4 fuček, l., matičec, d., vlahović, i., oštrić, n., prtoljan, b., korolija, b., korbar, t., husinec, a. & palenik, d. (2015): osnovna geološka karta republike hrvatske 1:50 000, list cres i lošinj [basic geological map of the republic of croatia, cres and lošinj sheet – in croatian].– hrvatski geološki institut, zagreb. garvue, m.m., spotila, j.a., cooke, m.l. & curtiss, e.r. (2024): what controls early restraining bend growth? structural, morphometric, and numerical modeling analyses from the eastern california shear zo­ ne.– tectonics, 43, e2023tc008148. https://doi.org/10.1029/2023tc008148 https://doi.org/10.1186/s00015-023-00437-0 https://doi.org/10.1186/s00015-023-00437-0 g eologia c roatica 265korbar et al.: conflicting tectonic interpretations of the central external dinarides herak, m. (2025): croatian catalogue and database of focal mechanism so­ lutions, characteristic mechanisms, and stress field properties in the di­ narides and the surrounding regions.– geofizika, 41/2, 79–123. http://doi. org/10.15233/gfz.2024.41.5 herak, m. & bahun, s. (1979): the role of the calcareous breccias (jelar formation) in the tectonic interpretation of the high karst zone of the di­ narides.– geološki vjesnik, 31, 49–59. herak, m., bojanić, l., šikić, d. & magdalenić, a. (1961): novi elementi tektonike u području gornjeg toka rijeke kupe [in croatian].– geološki vjesnik, 14, 245–251. kapuralić, j., šumanovac, f. & markušić, s. (2019): crustal stru­ cture of the northern dinarides and southwestern part of the pannonian basin inferred from local earthquake tomography.– swiss journal of ge­ osciences, 112, 181–198. https://doi.org/10.1007/s00015-018-0335-2 kochansky-devidé, v. & pantić, s. (1965): meandrospira u donjem i srednjem trijasu i neki popratni fosili u dinaridima [meandrospira in der unteren und mittleren trias sowie einige begleitende fossileien in der dinariden – in croatian and german].– geološki vjesnik, 19, 15–35, zagreb. korbar, t. (2009): orogenic evolution of the external dinarides in the ne adriatic region: a model constrained by tectonostratigraphy of upper cre­ taceous to palaeogene carbonates.– earth-science reviews, 96/4, 296– 312. http://dx.doi.org/10.1016/j.earscirev.2009.07.004 korbar, t., markušić, s., hasan, o., fuček, l., brunović, d., belić, n., palenik, d. & kastelic, v. (2020): active tectonics in the kvarner region (external dinarides, croatia) – an alternative appro­ ach based on focused geological mapping, 3d seismological, and shallow seismic imaging data.– frontiers in earth science, 8, 582797. https://doi.org/10.3389/feart.2020.582797 moulin, a., benedetti, l., rizza, m., jamšek rupnik, p., gosar, a., bourlès, d., keddadouche, k., aumaître, g., arnold, m., guillou, v. & ritz, j.f. (2016): the dinaric fault system: lar­ ge­scale structure, rates of slip, and plio­pleistocene evolution of the tran­ spressive northeastern boundary of the adria microplate.– tectonics, 35, 2258–2292. https://doi.org/10.1002/2016tc004188 mouthereau, f., lacombe, o. & vergés, j. (2012): building the za­ gros collisional orogen: timing, strain distribution and the dynamics of arabia/eurasia plate convergence.– tectonophysics, 532–535, 27–60. https://doi.org/10.1016/j.tecto.2012.01.022 picha, f.j. (2002): late orogenic strike-slip faulting and escape tectonics in frontal dinarides-hellenides, croatia, yugoslavia, albania, and greece.– aapg bulletin, 86/9, 1659–1671. https://doi.org/10.1306/61eedd32173e-11d7-8645000102c1865d placer, l., vrabec, m. & celarc, b. (2010): the bases for understan­ ding of the nw dinarides and istria peninsula tectonics.– geologija 53/1, 55–86, https://doi.org/10.5474/geologija.2010.005 prelogović, e., aljinović, b. & bahun, s. (1995): new data on stru­ ctural relationships in the northern dalmatian dinaride area.– geologia croatica, 48/2, 167–176. schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine-carpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss journal of geosciences, 101, 139– 183. https://doi.org/10.1007/s00015-008-1247-3 schmid, s.m., fügenschuh, b., kounov, a., maţenco, l., nievergelt, p., oberhänsli, r., pleuger, j., schefer, s., schuster, r., tomljenović, b., ustaszewski, k. & van hinsbergen, d.j.j. (2020): tectonic units of the alpine collision zone between eastern alps and western turkey.– gondwana research, 78, 308–374. https://doi.org/10.1016/j.gr.2019.07.005 sokač, b., nikler, l., velić, i. & mamužić, p. (1974): osnovna geo­ loška karta sfrj 1:100 000, list gospić l 33-127 [basic geological map of sfry 1:100 000, gospić sheet l 33-127 – in croatian].– institut za ge­ ološka istraživanja, zagreb, savezni geološki zavod, beograd. sokač, b., šušnjar, m., bukovac, j. & bahun, s. (1976): osnovna geološka karta sfrj 1: 100 000. tumač za list udbina l 33-128 [basic geological map of sfry 1: 100 000, udbina sheet l 33-128 – in croa­ tian].– institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd, 62 p. stewart, s.a. (2020): scale dependence of strike and dip in sedimentary basins: implications for field measurements and integrating subsurface datasets.– journal of structural geology, 131, 103943. https://doi.or­ g/10.1016/j.jsg.2019.103943 šumanovac, f., hegedűs, e., orešković, j., kolar, s., kovács, a.c., dudjak, d. & kovács, i.j. (2016): passive seismic experiment and receiver functions analysis to determine crustal structure at the con­ tact of the northern dinarides and southwestern pannonian basin.– geophysics journal international, 205, 1420–1436. http://doi.org/10.1093/ gji/ggw101 šušnjar, m., sokač, b., bahun, s., bukovac, j., nikler, l. & iva­ nović, a. (1973): osnovna geološka karta sfrj 1: 100 000, list udbina l 33-128 [basic geological map of sfry 1:100 000, udbina sheet l 33-128 – in croatian].– institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd. tari kovačić, v. & mrinjek, e. (1994): the role of palaeogene clastics in the tectonic interpretation of northern dalmatia (southern croatia).– geologia croatica, 47/1, 127–138. van hinsbergen, d.j.j., torsvik, t.h., schmid, s.m., maţenco, l., maffione, m., vissers, r.l.m., gürer, d. & spakman, w. (2020): orogenic architecture of the mediterranean region and kine­ matic reconstruction of its tectonic evolution since the triassic.– gond­ wana research, 81, 79–229. https://doi.org/10.1016/j.gr.2019.07.009 velić, i., velić, j., vlahović, i. & cvetković, m. (2014): geološki vodič kroz np paklenica [geological guide of np paklenica – in croa­ tian].– ju np paklenica, starigrad paklenica, 325 p. vičič, b., aoudia, a., javed, f., foroutan, m. & costa, g. (2019): geometry and mechanics of the active fault system in western slovenia.– geophysics journal international, 217, 1755–1766. https://doi.org/10.1093/ gji/ggz118 vlahović, i., mandic, o., mrinjek, e., bergant, s., ćosović, v., de leeuw, a., enos, p., hrvatović, h., matičec, d., mikša, g., nemec, w., pavelić, d., pencinger, v., velić, i. & vranj­ ković, a. (2012): marine to continental depositional systems of outer dinarides foreland and intra-montane basins (eocene-miocene, croatia and bosnia and herzegovina).– in: 29th ias meeting of sedimentology – journal of alpine geology, 55, 405–470. web sources: bgm (1965 – 1984): basic geological maps of former yugoslavia in scale 1:100,000. federal geological institute, belgrade, prepared by institute of geology, zagreb available at: https://www.hgi-cgs.hr/en/geoloske-kar­ te/. accessed on: february 15th 2023. dgu (2023): the croatian state geodetic administration. topographic map of croatia 1:25,000. available at: https://geoportal.dgu.hr/. accessed on: january 15th 2023. pmf (2025): department of geophysics, faculty of science, university of za­ greb. earthquakes web page. available at: https://www.pmf.unizg.hr/geof/ popularizacija_geofizike/o_potresima?@=1ohdn#news_133606. acces­ sed on: may 15th 2025. https://doi.org/10.3389/feart.2020.582797 https://doi.org/10.1007/s00015-008-1247-3 https://www.hgi-cgs.hr/en/geoloske-karte/ https://www.hgi-cgs.hr/en/geoloske-karte/ https://geoportal.dgu.hr/ 2020 | 73/3 | 153–175 | 14 figs. | 2 tabs. | 2 suppl. tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the studied area is located in the middle part of croatia (fig. 1a), in the south-western part of the pannonian basin system (pbs) (horváth & royden, 1981; royden, 1988) and belongs to the north croatian basin (ncb) (pavelić & kovačić, 2018). the investigated litostratigraphical column of hrvatska kostajnica (kos-i) (45.228337 °n, 16.559051 °e) represents the main scarp of the landslide located in the hrvatska kostajnica area on the eastern slopes of the kubarnovo brdo hill, north of the una river and west of the kostajničica stream. soil breakdown and sliding formed 30 m outcrop of the badenian–sarmatian marly deposits on which sedimentological, mineralogical, geochemical and palaeontological investigations were performed. the simplified basic geological map of the sfry, 1 : 100 000, kostajnica (fig. 1b) represents the latest complete geologi cal investigation of the area of hrvatska kostajnica. according to jovanović & magaš (1986a, 1986b), a broader landslide area is composed of neogene and quaternary deposits. badenian deposits conformably overlie early miocene sediments and disconformably/transgressively cover eocene sediments and volcanic-sedimentary sequences. the lower sarmatian deposits conformably overlie badenian deposits and contain marls and clayey limestones. according to recent research, the ncb during the early miocene was predominantly characterised by a fresh-water depositional environment. marine sedimentation began in the middle badenian (ćorić et al., 2009; brlek et al., 2016; pavelić & kovačić, 2018 and mandic et al., 2019a) when this basin was connected to the hrvatsko zagorje basin (hzb). the badenian marine sedimentation was presented by the deposition of marls palaeoecological and sedimentological characterisation of middle miocene sediments from the hrvatska kostajnica area (croatia) anita grizelj1, monika milošević1, koraljka bakrač1, ines galović1, tomislav kurečić1, valentina hajek-tadesse1, radovan avanić1, mirjana miknić1, marija horvat1, ana čaić janković1 and mario matošević2 1 hgi-cgs – croatian geological survey, department of geology, sachsova 2, 10 000 zagreb, croatia; (corresponding author: agrizelj@hgi-cgs.hr) 2 ina – industrija nafte d.d, exploration & production, exploration & upstream portfolio development, rock & fluid analysis, lovinčićeva 4, 10 000, zagreb, croatia doi: 10.4154/gc.2020.15 abstract the miocene deposits of the hrvatska kostajnica (kos-i) area belong to the south-western marginal part of the pannonian basin system (pbs). investigation of the lithostratigraphical column included: mineralogical, geochemical, sedimentological and integrated palaeontological (calcareous nannofossil, foraminifers, ostracodes, palynomorphs) analyses. badenian and sarmatian sediments of this column were deposited in a marine offshore environment with local input of terrigenous material represented by marls and silty marls. based on palaeontological data, the recorded palaeoclimate was subtropical in the late badenian changing to a warm temperate climate of the early sarmatian. marly sediments predominantly consist of carbonate (calcite and aragonite) and clay minerals, while quartz and plagioclase are less abundant. most samples contain a small amount of zeolite minerals from the clinoptilolite/heulandite series. among the clay minerals, smectite and illite/muscovite are the most abundant. based on provenance analyses we concluded that the badenian-sarmatian marls were predominantly formed by the weathering of acidic (si-rich) source rock derived material from the neighbouring inner dinarides. in the offshore environment (vejalnica formation) and coarsegrained material in the shoreface depositional environment (trstenik member and vrapče formation) (avanić et al., 2018). during the sarmatian, reduced salinity occurred, while sediments were represented by shallow-water conglomerates, calcarenites and limestones (the pećinka member) as well as horizontally laminated pelitic sediments (the dolje formation) deposited in a deeper marine environment (avanić et al., 2018; pavelić & kovačić, 2018 and references therein). studies of the provenance of the middle miocene sedimentary rocks of the sw margin of ncb are deficient. the only reliable data about the provenance of these sedimentary rocks are from areas n and ne of hrvatska kostajnica investigated by kovačić et al. (2011) and grizelj et al. (2017). according to these investigations in the area of medvednica mt. and the slavonian mts., the sources of material for the middle miocene clastic sedimentary rocks were located to the south of the investigated area, in the area of the northern inner dinarides, while some of the material was also supplied from locally uplifted blocks in the sw part of the pbs. the aim of this paper is to reconstruct the badenian/sarmatian transition in the area of the sw marginal part of the ncb and pbs based on a multiproxy approach: mineralogical, geochemical, sedimentological and integrated palaeontological analyses (calcareous nannofossil, foraminifers, ostracodes, palynomorphs determination) and palaeoecological reconstruction putting the results in the frame of new chronostratigraphic divisions within the middle miocene. furthermore, the aim of the present study is also to make a contribution to the discussion about the evolution, palaeogeography and climate history of the marine succession in the south-western pbs. article history: manuscript received july 29, 2020 revised manuscript accepted october 05, 2020 available online october 23, 2020 keywords: pannonian basin system, hrvatska kostajnica area, badenian, sarmatian, microfossils, pelitic sedimentary rocks, provenance g eo lo gi a c ro at ic a geologia croatica 73/3154 2. geological settings the pbs represents one of the mediterranean back-arc basins, which is surrounded by mountain chains comprising the alps, carpathians, and dinarides. furthermore, it includes several different-sized, deep depressions (sub-basins) separated by a comparatively shallow complex of basement rocks (horváth & royden, 1981; royden, 1988), which influenced the distribution of marine organisms and the development of stress-tolera nt species (steininger et al., 1988; galović & young, 2012). palaeogeographically, it belongs to the central paratethys figure 1. geographic and geological settings of the lithostratigraphical column hrvatska kostajnica (kos-i) within the kubarnovo brdo landslide: a. map of the principal tectonic and geographic units of the area of the pbs with an indicated position for the hzb and ncb (simplified after cvetković et al., 2019). b. geological map of the hrvatska kostajnica area, simplified after the basic geological map of sfry, 1:100.000, sheet kostajnica (jovanović & magaš, 1986a) showing the position of the investigated outcrop. stratigraphic and lithological legend: m4 – badenian: layered marls & sandstones; m5 1 – sarmatian: marls & clayey limestones; m5 2 – sarmatian: laminated sands with clays & gravels; m6 1 – pannonian: clayey limestones; q – quaternary: alluvial & slope deposits. g eologia c roatica grizelj et al.: palaeoecological and sedimentological characterisation of middle miocene sediments from the hrvatska kostajnica area (croatia) 155 realm, a sedimentation area that, during the miocene lost and reestablished connections with the mediterranean and the indopacific ocean on several occasions (harzhauser & piler, 2007; kováč et al., 2017; 2018). thus, the early/late badenian boundary was marked by a gradual weakening in the connection with the mediterranean sea, leading to the interruption of the water exchange between the western and eastern central paratethys (kováč et al., 2017). this event is called the badenian salinity crisis (bsc) which began at 13.81± 0.08 ma (de leeuw et al., 2010). moreover, gradstein et al. (2012) observed a causal relationship between cooling during the glacial event mi-3b (13.81 ma) and evaporite formation. formation of the pbs back-arc basin began in the early miocene with continental collision and subduction of the european plate beneath the apulian plate. in the area of north croatia during the early miocene two basins with different depositional histories evolved: the hrvatsko zagorje basin (hzb), which occupied a small area in north-western croatia, and the north croatian basin (ncb), that covered almost the entire area of north croatia (pavelić & kovačić, 2018). the syn-rift phase of basin development was characterized by tectonic thinning of the crust and isostatic subsidence, while the post-rift phase was marked by subsidence caused by cooling of the lithosphere (horváth & royden, 1981; royden et al., 1983; royden, 1988). in the south-western part of the pbs, the syn-rift phase lasted from the ottnangian to the middle badenian, while the post-rift phase extended from the late badenian to the end of the quaternary (pavelić & kovačić, 2018). the oldest deposits of the ncb are early miocene fresh-water, alluvial deposits (avanić et al., 2003; 2018, pavelić, 2001, pavelić & kovačić 1999). these deposits were covered by lower badenian marls and sandstones deposited in a hydrologically open lake (pavelić et al., 1998, pavelić & kovačić, 2018 and references therein). the lacustrine environment was replaced by marine environments with a transitional brackish interval (pavelić et al., 1998; hajek-tadesse et al., 2009). at the beginning of the middle badenian, due to the marine connection, lithothamnium limestones, sandstones and marls intercalated with pyroclastic rocks (caused by occasional volcanic activity) were deposited (avanić et al., 2003, pavelić et al., 1998). the badenian/sarmatian transition is correlated with the top of polarity chron c5ar2n at 12.829 ma (hohenegger et al., 2014 and references therein). in the sarmatian, the connections of the pbs with marine areas were significantly reduced which caused changes in depositional environments from marine to marine with reduced salinity and stratification. sarmatian marls and sandstones were deposited mostly conformable on the badenian deposits (pavelić, 2001; pavelić & kovačić, 2018 and references therein). 3. methods 3.1. fieldwork fieldwork included the following: outcrop rigging and sampling via single rope technique, in situ determination of sediment type, observation of the type of contacts between intervals, measurement of the dimensions of the sedimentary bodies, sampling for various analyses and finally construction of a lithostratigraphic column. 3.2. mineralogical and geochemical analysis mineralogical and geochemical analysis included the following: x-ray powder diffraction (xrpd) analyses (6 samples), chemical analysis of major and trace elements (7 samples) and measurement of caco3 using scheiblers calcimeter (15 samples). preparation for xrpd analyses included: sieving the samples through the 63 µm sieve, carbonate fraction dissolution by acetic acid with ammonium acetate (1 mol dm-3) buffer of ph 5 (jackson, 1956) and separation of the < 2 µm fraction from the insoluble residue of the sample. xrpd patterns were recorded on random mounts of bulk samples, fraction < 63 µm and oriented mounts of the < 2 µm fraction using the philips vertical goniometer (type x`pert) equipped with a cu-tube (hgi-cgs), and using the following experimental conditions: 45 kv, 40 ma, pw 3018/00 pixcel detector, primary beam divergence 1/4° and continuous scan (step 0.02 °2θ/s). oriented mounts of the < 2 µm fraction were recorded after the following treatments: a) air drying, b) ethylene-glycol solvation, c) heating to 400°c and 550°c. the x-ray interpretation was performed using the high score plus (2016) calculation and pdf-4 / minerals 4.5 (2020) databases. quantitative analysis was performed according to schultz (1964). chemical analyses of samples were undertaken by the bureau veritas commodities canada ltd., (www.acmelab.com) in vancouver (canada). after lithium borate (libo2) fusion, the major elements content was determined by inductively coupled plasma emission spectroscopy (icp-es), while trace elements were measured on an inductively coupled plasma mass spectrometer (icp-ms). provenance analyses were performed following the results of chemical analysis of major and trace elements using oxide or elemental ratios, ternary diagrams and diagrams based on the ele mental ratios. reconstruction of provenance based on the major elements was performed by sio2/al2o3, k2o/al2o3 and na2o/k2o ratios. for the analysis of provenance based on trace element content, elemental ratios dependant on provenance including la/co, th/co, th/sc, th/cr, eu/eu* [eu*=tb·(sm/tb)-⅔], lree/ hree and diagrams la-th-sc, th-sc-zr/10, nb/y – zr/tio2 proposed by bhatia & crook (1986), cullers (1994; 2000) and winchester & floyd (1977) were used. the degree of chemical weathering of the source rocks was constrained by calculating the chemical index of alteration (cia= [al2o3/(al2o3+cao*+na2o+k2o)]x100 (nesbitt & young, 1982). oxides are expressed in molar proportions and cao* is the amount of cao in siliciclastic minerals only, i.e. excluding carbonates and apatite. the data for cao* have been corrected according to the procedure described by mclennan (1993). because all the analysed samples contained significant amounts of carbonate component, it was assumed that the correction of cao is equal to that of na2o. 3.3. palaeontological analysis 3.3.1. calcareous nannofossil analyses the preparation method of shamrock et al. (2015) was followed for tlm (transmitted light microscope) analyses of calcareous nannofossils, while for sem (scanning electron microscope) analyses, calcareous nannofossils were coated with gold. slides were examined using an olympus bh-2 tlm (hgi-cgs) and jeol jsm-6510 lv sem (ina – industrija nafte d.d.). the relative abundance of the calcareous nannoplankton was estimated after randomly counting more than 200 coccoliths along transects at 750x magnification (using a 60 x objective) according to schmidt (1978). g eo lo gi a c ro at ic a geologia croatica 73/3156 figure 2. lithostratigraphic column of the hrvatska kostajnica showing sample position, caco3 content, fossil distribution and sedimentological history with a palaeoenvironmental interpretation. g eologia c roatica grizelj et al.: palaeoecological and sedimentological characterisation of middle miocene sediments from the hrvatska kostajnica area (croatia) 157 3.3.2. palynological analyses palynological analyses were carried out on four samples collected from the lower 10 m of the column. standard palynological processing techniques were used to extract the organic matter (e.g. moore et al., 1991; wood et al., 1996). the samples were treated with sodium pyrophosphate (na4p2o7), cold hcl (15%) and hf (40%), to remove carbonates and silica. heavy liquid (zncl2, density >2.1 kg/l) was used to separate the organic matter from the undissolved inorganic components. the organic residue was sieved through a 10 µm mesh. for palynofacies analysis slides were mounted in glycerine and for palynomorphs analysis in silicon oil. microscopic analyses were performed using an olympus bh-2 and leica dm2500 microscopes (hgi-cgs). photomicrographs were taken using an amscopetm camera adapter connected to the amscope v.3.7 camera software and a leica mc190 hd camera connected to the leica las ez software. the palynofacies analyses represent qualitative examinations of the organic matter component groups according to the classifications proposed by tyson (1995). samples are plotted in the aom-phytoclast-palynomorph (app) ternary diagram to characterize the palaeoenvironment according to tyson (1995). 3.3.3.. foraminiferal and ostracod analyses altogether 12 samples along the column were prepared for ostracod and foraminiferal analyses, both benthic and planktonic species. approximately 200 g of sediment per sample was disaggregated by soaking in diluted hydrogen peroxide for 48 h, then washed through sieves (0.25; 0.125; 0.09 and 0.063 mm) and dried at room temperature. all fossil remains (ostracods, foraminifera, bryozoans, gastropods, pteropods, bivalves fragments, otoliths, and fish remains) were hand-picked from each dried residue and observed under a binocular microscope (wild m3z) and zeiss stereomicroscope. all picked specimens were classified and counted but not statistically analyzed. planktic and benthic foraminifers are mainly classified based on cicha et al. (1998); popescue & crihan (2004; 2005 a,b; 2008; 2011); filipescue & silye (2008); gedl et al. (2016); peryt et al. (2014); schütz et al. (2007); dumitriu et al. (2017) and tóth et al. (2010). ostracod species identifications were based on van morkhoven (1963), hartmann & puri (1974) and horne et al. (2002). to interpret palaeoenvironmental conditions, calcareous benthic foraminifera are divided into different morphogroups based on their test morphology and mode of coiling. this widely used approach shows the relationship between the test morphology and ecological life preference of modern benthic taxa (silye, 2015 and references therein,). ecological conditions required for each foraminiferal species are mainly accepted from murray (2006) and silye (2015) and references therein. specimens considered stratigraphically important were documented using the sem jeol jsm-35cf system at the hgicgs. all micropalaeontological samples, organic residues and paly nological slides are curated at the department of geology, hgi-cgs, zagreb, croatia. 4. results 4.1. sedimentology the hrvatska kostajnica (kos-i) lithostratigraphic column has a total thickness of 25.6 m, which consists of upper badenian and sarmatian pelitic sedimentary rocks (figs. 1b, 2). field research and measurement of caco3 has shown that the column consists of marls, and clayey limestones, while calcareous marls and silty marls are rare. marls contain 48-60% caco3, silty marls 29-49% caco3, calcareous marls 77% caco3 and clayey limestones 81-88% caco3 (fig. 2). there is visible bedding dipping toward the north (n-nw) at a 10° angle, although the internal structure in individual layers is rarely visible. lithological boundaries between the described intervals are mostly sharp and planar or gradational, except at 1.3 m and 6.6 m from the base of the outcrop, where the boundary is described as sharp and irregular. horizontal lamination is present in the lower part of the outcrop and rarely in the upper part. at the top of the outcrop (from 22.6 to 25.6 m) there are bioturbation marks. finally, there is no clearly visible discordance between the lower (badenian) and upper (sarmatian) parts of the lithostratigraphical column. 4.2. mineralogy and geochemistry the mineralogical composition and chemical composition of the marl samples are given in tab. 1. table 1 shows the results of the quantitative mineral composition of the bulk marl samples and semi-quantitative results of the fraction < 63 µm and < 2 µm of the insoluble residue obtained by xrpd. the main mineral components are calcite and clay minerals while quartz and aragonite are present in a lesser quantity. in the fraction < 63 µm of insoluble residue, besides clay minerals and quartz, all samples contain a small amount of plagioclase. zeolites from the clinoptilolite/heulandite series are present in a lesser quantity in all samples except sample 15 (fig. 3 and tab. 1). sample 1 contains a small amount of pyrite. in the fraction < 2 µm of insoluble residue smectite/i-s and illite/mustable 1. quantitative mineral composition of bulk samples and the semi-quantitative mineral composition of the <63 µm fraction of insoluble rock residue obtained by xrpd according to the procedure described by schultz (1964). clay mineral content was determined from the <2 μm fraction of insoluble rock residue. qtz – quartz, cal – calcite, arg – aragonite, cli/hul – clinoptilolite/heulandite, pl – plagioclase, py – pyrite, sme/i-s – smectite/illite-smectite, ill/ms – illite/muscovite, vrm – vermiculite, kln – kaolinite, chl – chlorite, xxx – dominant (>50%), xx – abundant (20-50%), x – subordinate (1-20%), + – traces (<1%). sample kos-i 1 4 5 9 11 15 bulk sample (wt. %) qtz 7 8 11 11 8 7 cal 41 38 33 16 59 58 arg 18 18 16 13 clay 34 36 40 60 31 35 <63 µm qtz xx xx xx x xx xx clay xxx xxx xxx xxx xxx xxx cli/hul + x x x x pl x x x x + x py x <2 µm sme/i-s xx xx xx xx xx xx ill/ms xx xx xx xx xx xx vrm + + kln x x x x x x chl + + + qtz + + + + + g eo lo gi a c ro at ic a geologia croatica 73/3158 covite are well represented in all samples, while kaolinite is present in all samples in a lesser quantity (tab. 1 and fig. 4). quartz is present in trace amounts in all samples except sample 15. vermiculite and chlorite were determined in only a few samples (tab. 1). in tab. 2, besides the chemical composition of marl sediments, the major element oxide ratios, trace element ratios, and the cia index are listed. 4.3. micropalaeontology 4.3.1. calcareous nannofossil assemblages among 42 taxa of calcareous nannofossils based on the occurrence frequency, 13 taxa were identified in all samples: calcidis­ cus leptoporus, ca. pataecus, coccolithus pelagicus, cyclicar­ golithus f loridanus, helicosphaera carteri, pontosphaera longiforaminis, reticulofenestra haqii, r. minuta, r. minutula, figure 3. xrd pattern of the <63 µm fraction of the insoluble rock residue. a: kos-i 1, b: kos-i 4, c: kos-i 5, d: kos-i 9, e: kos-i 11, f: kos-i 15. abbreviations are the same as in table 1. figure 4. xrd pattern of the <2 µm fraction of insoluble rock residue of sample kos-i 1 recorded after the following treatments: red line: air-dried sample, grey line: ethylene-glycol treated sample, blue line: sample heated to 400°c; green line: sample heated to 550°c. g eologia c roatica grizelj et al.: palaeoecological and sedimentological characterisation of middle miocene sediments from the hrvatska kostajnica area (croatia) 159 rhabdosphaera sicca, sphenolithus abies, syracosphaera clath­ ratae, umbilicosphaera rotula. two main biostratigraphic zones nn6 and nn7 were identified (martini, 1971) (fig. 2). species diversity is highest (36 taxa) in zone nn7 in sample 9, while up to 32 taxa were determined in zone nn6 in sample 1. the most equally dominant species in the record (up to 24%) are coc­ colithus pelagicus and umbilicosphaera jafari, followed by less abundant reticulofenestra producta (up to 17%), r. minuta (up to 16%), small reticulofenestra sp. (up to 14%) and reticulofen­ estra haqii (up to 12%). all scattered and rare taxa (≤ 9%) are omitted from the results because they did not affect the palaeoecological interpretations. on the other hand, two rare index species (calcidiscus pataecus and discoaster kugleri) contributed to the biostratigraphy. late badenian nn6c subzone (mărunţeanu, 1999; amended by galović, 2019) (0-5.7 m) the first occurrence (fo) of calcidiscus pataecus is characteristic for the late badenian where it marks subzone nn6c of paratethys (mărunţeanu, 1999). umbilicosphaera jafari (up to 24%) is the main component in the assemblage with equally abundant (up to 14%) small re­ ticulofenestra (reticulofenestra sp., r. minuta, r. producta) and less abundant small coccolithus pelagicus (up to 12%) and re­ ticulofenestra haqii (up to 11%) (figs. 2, 5). early sarmatian nn6d?-nn7a subzone (galović, 2019) (7.8-23.5 m) the first occurrence (fo) of discoaster kugleri is characteristic for the early sarmatian subzone nn7a of paratethys (galović, 2019). small to medium-sized coccolithus pelagicus (up to 24%) dominates in the assemblage with less abundant small reticu­ lofenestra producta (up to 17%), r. minuta (up to 16%) and r. haqii (up to 12%) (figs. 2, 5). 4.3.2. palynology all samples contain palynomorphs in various amounts. the preservation degree of the grains is medium to good, i.e. the structure and sculpture of several grains are partially destroyed, making more precise determination impossible. in the lower part of the column (samples 1 and 4), gymnosperm species (mostly pinus) prevailed (90%). the dinocyst assemblage is dominated by chorate gonyaulacoids (cleisto­ sphaeridium placacanthum (fig. 5/17), lingulodinium machaerophorum, polysphaeridium zoharyi, spiniferites ramo­ sus (fig. 5/16), melitasphaeridium choanophorum (fig. 5/15), hystrichokolpoma rigaudiae (fig. 5/13), operculodinium cen­ trocarpum, op. piaseckii, achomosphaera andalousiensis (fig. 5/14), nematosphaeropsis labyrinthus (fig. 5/18), n. lemniscata, dapsilidinium sp.? cordosphaeridium minimum). in addition, proximate gonyaulacoids (cerebrocysta poulsenii, batiacas­ phaera sphaerica) are also present, as well as prasinophyte algae titthodiscus mecsekensis, and foraminifera linings. the dinocyst assemblage indicate the cleistosphaeridium placacanthum zone (cpl), bakrač et al. (2012), and the cerebrocysta poulsenii assemblage biozone (cpo), jimenez-moreno et al. (2006). the palynofacies is dominated by the amorphous group, mainly derived from terrestrially degraded material (roughly 40-45%), whereas the phytoclast group is the second most dominant (35%) and the palynomorph group is the least (20-25%). pyrite inclusions, resins and charcoal are present. the depositional environtable 2. content of major (wt. %), trace elements (ppm) and some ratios and cia weathering index. elements kos-i 1 4 5 6 9 11 15 sio2 21.41 25.08 28.79 9.44 38.43 22.73 23.66 al2o3 6.73 7.34 8.77 3.00 12.29 6.53 6.77 fe2o3 2.40 1.31 3.12 1.42 5.17 2.58 2.29 mgo 0.99 1.02 1.12 0.66 1.57 0.95 1.23 cao 34.02 32.07 27.69 45.96 17.33 33.69 32.97 na2o 0.38 0.44 0.45 0.15 0.63 0.33 0.28 k2o 1.17 1.32 1.66 0.54 2.27 1.19 1.23 tio2 0.33 0.39 0.45 0.15 0.70 0.33 0.36 p2o5 0.15 0.13 0.22 0.06 0.08 0.21 0.23 mno 0.01 0.01 0.02 0.02 0.03 0.01 0.02 cr2o3 0.01 0.02 0.02 0.01 0.02 0.01 0.01 ba 225.00 517.00 629.00 219.00 535.00 494.00 165.00 ni 91.00 54.00 72.00 38.00 102.00 65.00 57.00 sc 7.00 8.00 9.00 4.00 13.00 7.00 7.00 loi 32.10 30.50 27.30 38.40 21.10 31.10 30.70 sum 99.71 99.69 99.71 99.83 99.73 99.76 99.80 tot/c 9.93 8.18 6.40 10.81 5.22 7.77 7.70 tot/s 1.18 0.12 0.04 <0,02 2.14 0.03 <0,02 v 172.00 183.00 189.00 72.00 206.00 150.00 161.00 cr 95.79 109.48 116.32 41.05 123.16 88.95 68.42 co 5.80 3.00 7.90 1.80 13.10 2.80 3.90 ga 7.30 8.00 9.90 3.00 13.60 6.30 6.60 rb 58.20 65.50 76.30 25.20 107.30 57.40 57.40 sr 1685.00 1796.70 1570.40 983.10 1118.60 1308.40 920.50 y 16.90 17.90 20.00 8.20 21.40 16.40 17.50 zr 73.00 78.20 86.80 30.80 127.10 70.20 76.30 nb 5.90 7.00 7.40 2.80 11.50 5.80 6.10 th 5.00 5.20 6.10 1.90 8.50 4.70 4.90 cs 5.80 6.30 7.30 2.40 9.70 5.70 5.70 hf 2.20 2.30 2.30 0.70 3.30 1.90 2.00 la 17.60 18.50 22.40 8.60 26.40 17.20 18.20 ce 32.00 32.90 41.70 13.30 50.10 30.00 32.90 pr 3.92 3.92 4.93 1.66 5.79 3.57 4.00 nd 13.50 15.30 17.60 5.90 21.60 14.40 15.60 sm 2.82 2.97 3.70 1.20 4.22 2.69 3.01 eu 0.63 0.66 0.75 0.28 0.80 0.59 0.65 gd 2.75 3.01 3.65 1.31 3.80 2.78 2.87 tb 0.47 0.49 0.58 0.22 0.62 0.42 0.47 dy 2.64 2.78 3.40 1.27 3.65 2.69 3.02 ho 0.62 0.60 0.75 0.30 0.75 0.56 0.56 er 1.70 1.76 2.21 0.87 2.29 1.62 1.73 tm 0.26 0.25 0.31 0.13 0.34 0.23 0.26 yb 1.62 1.58 1.92 0.81 2.15 1.43 1.53 lu 0.29 0.25 0.33 0.12 0.32 0.22 0.25 sn 2.00 2.00 2.00 <1 3.00 1.00 2.00 ta 0.50 0.50 0.40 0.20 0.60 0.40 0.40 u 7.00 14.60 5.70 3.40 14.10 5.80 7.10 sio2/al2o3 3.18 3.42 3.28 3.15 3.13 3.48 3.49 al2o3/ti2o 20.39 18.82 19.49 20.00 17.56 19.79 18.81 k2o/al2o3 0.17 0.18 0.19 0.18 0.18 0.18 0.18 na2o/k2o 0.20 0.33 0.27 0.28 0.28 0.28 0.23 la/co 3.03 6.17 2.84 4.78 2.02 6.14 4.67 th/co 0.86 1.73 0.77 1.06 0.65 1.68 1.26 th/sc 0.71 0.65 0.68 0.48 0.65 0.67 0.70 la/sc 2.51 2.31 2.49 2.15 2.03 2.46 2.60 th/cr 0.05 0.05 0.05 0.05 0.07 0.05 0.07 eu/eu* 0.49 0.50 0.51 0.32 0.53 0.46 0.50 lree/hree 6.36 6.47 6.50 5.77 7.34 6.44 6.50 ∑ ree 80.82 84.97 104.23 35.97 122.83 78.4 85.05 cia 72.76 71.82 72.77 73.54 73.04 73.31 75.01 g eo lo gi a c ro at ic a geologia croatica 73/3160 figure 5. 1. calcidiscus pataecus (sample 15) scale bar = 1 µ; 2. umbilicosphaera jafari (sample 5) scale bar = 1 µ; 3. small reticulofenestra species (sample 9) scale bar = 2 µ; 4. calcidiscus pataecus (sample 15) scale bar = 1 µ; 5. partially disintegrated coccosphaeres of coccolithus pelagicus (sample 1) scale bar = 5 µ; 6. palynofacies; pal-palynomorph pinus with pyrite grains; ph-phytoclast; aomamorphous organic matter (sample 9); 7. lingulodinium machaerophorum (sample 9), 8. operculodinium piaseckii (sample 9); 9. batiacasphaera sphaerica (sample 9); 10. impagidinium patulum (sample 6); 11. cerebrocysta poulsenii (sample 6); 12. titthodiscus mecsekensis (sample 6); 13. hystrichokolpoma rigaudiae (sample 4), 14. achomosphaera andalousiensis (sample 4), 15. melitasphaeridium choanophorum (sample 1), 16. spiniferites ramosus (sample 1); 17. cleistosphaeridium placacanthum (sample 1). 18. nematosphaeropsis labyrinthus (sample 1) scale bar = 10 µ for figs. 6-18. g eologia c roatica grizelj et al.: palaeoecological and sedimentological characterisation of middle miocene sediments from the hrvatska kostajnica area (croatia) 161 ment was a distal dysoxic-anoxic shelf according to the palynofacies (fig. 6). on land, zonal vegetation developed, represented by a warmtemperate mixed mesophytic forest, with a large contribution from extrazonal elements (mountain conifer-rich forest). above the horizon there is one thin layer (sample 6). dinocysts prevail (60 %), mostly chorate gonyaulacoids (spiniferites spp., cleistosphaeri­ dium placacanthum, lingulodinium machaerophorum, operculo­ dinium piaseckii). in addition, proximate gonyaulacoids (cerebro­ cysta poulsenii, fig. 5/11, impagidinium patulum, fig. 5/10) are also present, as well as chlorophyte algae botryococcus braunii, prasinophyte algae crassosphaera sp., and titthodiscus mecsek­ ensis (fig. 5/12). the assemblage indicates the cleistosphaeridium placacanthum zone (cpl), bakrač et al. (2012) and cerebro­ cysta poulsenii assemblage biozone (cpo) jimenez-moreno et al. (2006). the amount of the organic residue is very low in proportion and barely enough to allow palynofacies analysis. it is dominated by the palynomorph group (50%), whereas the phytoclast group was the second most dominant (40%). the amorphous group account for only ca. 10% of the organic particles. some phytoclasts are gelified. pyrite inclusions and charcoal are present. this palynofacies suggests that deposition took place in a mud-dominated oxic shelf environment (fig. 6). in the middle part of the column (sample 9), the dinocyst proportion is somewhat higher than gymnosperm pollen (mostly pinus). the dinocyst assemblage is dominated by chorate gonyaulacoids (spiniferites spp., cleistosphaeridium placacanthum, lingulodinium machaerophorum (fig. 5/7), polysphaeridium zo­ haryi, operculodinium piaseckii (fig. 5/8), melitasphaeridium choanophorum, labyrinthodinium truncatum). in addition, proximate gonyaulacoids (cerebrocysta poulsenii, batiacasphaera sphaerica (fig. 5/9) are also common, as well as prasinophyte algae titthodiscus mecsekensis, crassosphaera sp., mecsekia spinosa and foraminifera linings. the terrestrial palynolfora is represented only by elements characteristic for extrazonal vegetation such as montane conifer-rich forests. this assemblage is assigned to the polysphaeridium zoharyi – lingulodinium macha­ erophorum zone (pzo-lma) bakrač et al. (2012) and the cleistosphaeridium placacanthum assemblage biozone (cpl) jimenez-moreno et al. (2006). the palynofacies (fig. 5/6) is dominated by the phytoclast group (50%), whereas the amorphous group attains 40% of the particles, while the palynomorph group is the least abundant (10%) element. some phytoclast particles are gelified. pyrite inclusions and charcoal are present. according to the palynofacies from sample 9, the depositional environment was a proximal suboxic-anoxic shelf (fig. 6). alongside the zonal vegetation (warm-temperate mixed mesophytic forest at a very low ratio), extrazonal mountain coniferrich forests were developed. 4.3.3. foraminifera the distribution of foraminifera from the marl samples is given in supplement tab. 1 and fig. 7. altogether, 81 benthic and 31 planktonic species of foraminifera are determined in the lithostratigraphic kos-i column. large amounts of reworked badenian microfossils within the sarmatian sediments, together with the rare occurrence of sarmatian index fossils, is the main characteristic of the kos-i column. planktonic species are mostly represented by specimens of the genus globigerina, globigerinoides, together with orbulina species, globoturborotalita sp., and turborotalita quinqueloba, with rare occurrences of velapertina indigena, paragloborotalia siakensis, and globigerinita glutinata. benthic foraminifera are predominantly represented by calcareous species, miliolids are scarce, while agglutinated species are absent. an engaging feature of the benthic foraminiferal assemblage is the slightly higher occurrence of unicameral foraminifera. favulina hexagona, porosolenia tibiscens, fissurina severantoni, palliolatella sp. are species determined in the lower part of the column (samples 1 – 4). a high amount of bolivinids and buliminids is determined the kos-i column as a whole. benthic species have ranges varying from the early badenian (e.g. planularia moravica, lenticulina cf. clypeiformis, bolivina fas­ tigia, amphimorphina hauerina) to the late badenian (uvigerina brunnensis, pappina neudorfensis) which, together with the scarce occurrence of sarmatian index species (nonion bogdano­ wiczi) point to a high rate of reworking along the column. the sarmatian index fossil is identified in the upper part of the column (above sample 7). the lower part of the column due to the co-occurrence of bolivina dilatata, bulimina elongata longa, uvigerina brunnensis, u. semiornata together with globigerina bulloides, g. praebulloides, g concinna, and globigerinoides trilobus is attributed to the late badenian (dumitriu et al., 2017). furthermore, index fossils including nonion bogdanowiczi, bolivina sagittula, b. nisporenica, b. pseudoplicata, b. moravica, b. moldavica granensis, fursenkoina sarmatica, elphidium per­ scitum, e. ex gr. puscharovski, e. macellum tumidocamerale, e. incertum, e. excavatum, elphidiella artifex, and nonion tumidu­ lus point to the sarmatian age. benthic foraminiferal taxa, based on their test morphology and mode of coiling, were clustered into six morphogroups. morphogroup m1 is composed of forms with a rounded planispiral test (elphidiella, nonion, non-keeled elphidiids). they are present throughout the whole kos-i column. we presume that species from this group belong to the autochthonous assemblage. morphogroup m2 includes elphidiids (elphidium crispum, e. figure 6. palynofacies data (aom-phytoclast-palynomorph) presented based on tyson (1995) diagram. i highly proximal shelf or basin; ii marginal dysoxicanoxic basin; iii heterolithic oxic shelf (proximal shelf ); iv shelf to basin transition (iva dysoxic-suboxic; ivb suboxic-anoxic); v mud-dominated oxic shelf (distal shelf ); vi proximal suboxic-anoxic shelf; vii distal dysoxic-anoxic shelf; viii distal dysoxic-oxic shelf; ix proximal suboxic-anoxic basin. g eo lo gi a c ro at ic a geologia croatica 73/3162 figure 7. sem photomicrographs of selected foraminifers from the kos-i succession. 1. bolivina plicatella; 2. bolivina plicatella mera; 3. bolivina pseudoplicata; 4. bolivina moldavica; 5. bolivina moldavica granensis; 6. bolivina nisporenica; 7. bolivina moravica; 8. bolivina papulata; 9. bolivina sagittula; 10. bolivina sarmatica; 11. bolivina striatulla; 12. favulina hexagona; 13. fissurina severantoni; 14. cursina porocostata; 15. porosolenia tibiscens; 16. nonion biporus; 17. porosononion martkobi; 18. elphidium excavatum; 19. elphidium perscitum; 20. elphidium ex gr puscharovski; 21. elphidium reussi; 22. elphidiella artifex; 23. elphidiella vignaeuxi. g eologia c roatica grizelj et al.: palaeoecological and sedimentological characterisation of middle miocene sediments from the hrvatska kostajnica area (croatia) 163 macellum) of the shallow-shelf environment. morphogroup m3 is composed of the low trochospiral tests of ammonia. in the kos-i column, ammonia species are more frequent in sample 7. morphogroup m4 is composed of unilocular lagenids. this morphogroup characterizes the outer shelf to bathyal environments, suboxic marine environments with a low-moderate organic influx (silye, 2015 and references therein). in the kos-i column, they only appear in the lower part. morphogroup m5 is composed of two genera, bolivina and bulimina. morphogroup m6 represents low-trochospiral rotalids, cibicidoides and lo­ batula species. in samples from the kos-i column morphogroups with an infaunal mode of life prevail, while the epifaunal lifestyle is subordinate. 4.3.4. ostracods a total of 10 samples were used for ostracod analyses, taken successively from the kos-i column. twenty four ostracod taxa belonging to 15 genera were identified, of which eight species remained in open nomenclature. distributions of ostracod species are summarised in supplement tab. 2, listed alphabetically. some of the species are illustrated in fig. 8. the ostracod fauna within the kos-i succession includes marine ostracod species that represent six families: callisto­ cythere cf. postvallata, callistocythere canaliculata, cnesto­ cythere sp., cnestocythere truncata within cytheridae; aurila cf. notata, aurila cf. merita, aurila sp., bosquetina carinella, tenedocythere slebrosa, tenedocythere sp., tenedocythere sul­ catopunctata within the hemicytheridae; amnicythere ? sp. within the leptocytheridae; buntonia sp., costa sp., olimfalunia ? plicatula, grinioneis haidingeri within the trachyleberididae; paracytheridea triquetra, semicytherura filicata, semicytherura cf. alata within cytheruridae; loxoconcha sp., loxocorniculum hastatum, loxocorniculum cf. schmidi within the loxoconchidae; and xestoleberis glaberscens and xestoleberis sp. within the xestoleberidae. ostracods were discovered in small numbers in nine samples, and their species richness was low. ostracods were absent in sample 6. common species in samples from the kos-i column are: aurila sp. (8 records), callistocythere cf. postvallata (6 records) and xestoleberis glaberscens (4 records). the diversity varies throughout the column and is generally low. the maximum number of species (11) was reported in sample 11. sample 4 contain 10 species. other samples include relatively low numbers of species: samples 2 and 13; 7 species each, and samples 1 and 5 with 6 species each. in other samples, the number of species vari es between 3 and 4, and one sample contains only 2 species. 4.3.5. other microfossils rare bryozoans, probably crisia sp. and tubulipora sp. (samples 9 and 11), according to filipescu et al. (2014), prefer unstable, shallow and high energy environments. they usually belong to pioneer assemblages. pteropods, probably limacina valvatina, are recognized in samples 4 to 9. their occurrence is documented from the early to late badenian and even in the lower sarmatian (bošnjak et al., 2017 and references therein). according to bohn-havas & zorn (2002), the species was widely distributed during the badenian. 5. discussion 5.1. sedimentology the lithostratigraphic column in fig. 2 shows continuous sedimentation from the late badenian to the early sarmatian. such a situation is well known from the area of the ncb, where sarmatian sediments overlie upper badenian sediments in a continuous depositional succession (vrsaljko et al., 2006; pavelić & figure 8. sem photomicrographs of selected ostracods from the kos-i succession. 1. aurila cf. notata, rv external view; 2. semycytherura cf. alata, rv external view; 3. xestoleberis sp., rv external view; 4. aminocythere ? sp., rv external view; 5. loxocorniculum cf. schmidi, lv external view; 6. semicytherura filicata , rv external view; 7. loxocorniculum hastatum, rv external view; 8. 10. aurila sp., lv external view; 9. aurila cf. merita, rv, external view. scale bars: 100 μm. g eo lo gi a c ro at ic a geologia croatica 73/3164 kovačić, 2018). structureless marls, that are represented in most of the lithostratigraphic profile (fig. 2), suggest sedimentation of fine-grained siliciclastic material from suspension in an open marine environment. similar conditions recorded on the ne part of mt. medvednica indicate sedimentation in the deeper part of the basin which was not significantly affected by the sea-level fall at the end of the badenian (vrsaljko et al., 2006). the analysed samples contain calcite and in a lesser quantity aragonite. carbonates were predominantly deposited from seawater (discussed in section 4.2.). the small amount of carbonate content in the marls could be associated with carbonate detritus derived from fossil skeletons and bioerosion of older carbonate bedrock. the fragments of bryozoans, gastropods, pteropods, bivalves, otoliths, and fish remains, together with marine ostracods, foraminifera, calcareous nanofossils, and palynomorphs indicate a marine depositional environment. the absence of wave action indicators and the presence of palaeontological species from deeper marine environments suggests that sediments were deposited on the shelf or below the base of the wave action (offshore). in contrast, the badenian/sarmatian boundary is discontinuous in many cases within central paratethys (vrsaljko et al., 2006; mandic et al., 2019b; mandic et al., 2019c). this discontinuity is the result of the sea-level fall during the latest badenian, and the formation of archipelagoes which were affected by erosion resulting in the deposition of shallow-water sediments and reworked badenian flora and fauna (pavelić & kovačić, 2018). figure 9. shows the stratigraphic position of the kos-i column correlated with the ugljevik (mandic et al., 2019c) and donje orešje columns (vrsaljko et al., 2006; galović, 2003). the depositional environment of kos-i column is similar to the environment of the donje orešje. nevertheless, during the sarmatian deposition occured in the donje orešje in a lagoon, while in the studied area it continues in the deeper sea. the badenian/sarmatian boundary at the ugljevik column (bosnia and herzegovina) as in many other parts of pbs, is marked by a weakly expressed erosive omission and hiatus (mandic et al., 2019c). according to avanić et al. (2003), these differences were proba bly the result of local tectonics in the earliest post-rift phase that has a significant role controlling sedimentation in these part of the pbs. 5.2. mineralogical composition of marls the bulk analyses of marls show that the main mineral components are calcite and clay minerals, while quartz and aragonite are present in lesser quantities. the amount of aragonite is probably of biogenic and/or chemical origin. it is well known that the type of carbonate and its morphology depends on the temperature of the water in which it is generated, together with the concentration of ca2+ and mg2+ ions in the solution, salinity and pressure of co2 (rao, 1996). calcite may form when the mg/ca ratio is < 2, while aragonite occurs when the mg/ca ratio is between 2 and 12 (müller et al., 1972). moreover, calcite may occur in different environments, while aragonite is usually formed in warm (20–30 °c), shallow marine environments by direct precipitation from seawater, or it forms skeletons of various organisms (lippmann, 1973; rao, 1996; chang et al., 1998, tišljar, 2001). such marine and marine environments with reduced salinity existed during both the badennian and the sarmatian. also, part of the aragonite, that is unstable in the subsurface and at standard temperature and pressure, could be altered to the more stable isomorph calcite. in the fraction < 63 µm of insoluble residue, besides clay minerals and quartz, all samples contain a small amount of plagioclase and zeolites from the clinoptilolite/heulandite series. zeolites are present in almost all samples, indicating that they were probably transported from some local source of origin. such a local source could be the upper cretaceous deposits in the locality of volinja near kos-i column, in which marković (2002) mentions the occurrence of zeolite minerals. the results of previous provenance studies suggest also that the neighbouring inner dinarides produced a significant amount of clastic detritus during the middle miocene (kovačić figure 9. illustration showing the stratigraphic position of the investigated hrvatska kostajnica column (kos-i) and its correlation with the ugljevik (mandic et al., 2019c) and donje orešje columns (galović, 2003; vrsaljko et al., 2006). magnetostratigraphy is from hilgen et al. (2012). the geological time scale is from gradstein et al. (2012) and hohenegger et al. (2014). g eologia c roatica grizelj et al.: palaeoecological and sedimentological characterisation of middle miocene sediments from the hrvatska kostajnica area (croatia) 165 et al., 2011, grizelj et al., 2017). in the < 2 μm fraction of insoluble residue, the main components are smectite/i-s and illite/ muscovite, while kaolinite is present in a lesser amount. in some samples, chlorite and vermiculite are also present. while illite/ muscovite and chlorite are considered typical terrigenous mineral species, formed directly from disintegrating intrusive and metamorphic rocks, kaolinite and vermiculite are characteristic products of chemical weathering (chamley, 1989). it should also be noted that chlorite is poorly resistant to chemical weathering, which probably explains its presence in small amounts in the analysed marls. according to weaver (1989), most smectite occurs as interlayer i-s. smectites may form from the alteration of volcanic rocks in subaerial and submarine environments and do not suffer from marine and river transportation, and are often carried in the marine environment farther than other minerals because of their high buoyancy (chamley, 1989). in the investigated profile there were no traces of volcanic activity in the sediment. the occurrence of smectite could be explained by re-deposi tion from volcanic material from older formations such as tuffs that were determined in the area of banovina (mandic et al., 2012 and marković, 2017) or alteration of volcanic material which was transported over long distances. intensive volcanic activity was reported for the middle miocene in the wider area of the pbs (pamić et al., 1995; kováč et al., 2007; mandic et al., 2012; marković, 2017; brlek et al., 2020). 5.3. chemical composition and provenance of terrigenous material 5.3.1. major elements variation in the chemical composition of major elements of the samples may be explained by the observed variation in the mine ralogy of the samples. al2o3 values range between 3.00–12.29 wt %, an amount related to clay minerals, zeolites and plagioclase. the amount of al2o3 and other major elements is dictated to by the amount of cao, which is mainly related to the amount of calcite and/or aragonite in the samples. this is illustrated in fig. 4, which shows good positive correlations of sio2, fe2o3, mgo, na2o, k2o and tio2 with al2o3, while cao is strongly negatively corfigure 10. cross-plots of major oxides (wt. %) against al2o3 (wt. %) showing their correlations. g eo lo gi a c ro at ic a geologia croatica 73/3166 related. except for clay minerals, zeolites and plagioclase, a certain amount of sio2 is also associated with the amount of quartz (tab. 1). the sio2/al2o3 ratio proposed by cullers (2000) was used as an indicator of the maturity of the clastic sedimentary rocks, as well as for the presence of quartz in relation to the clay minerals and feldspar. this ratio in all samples ranges from 3–3.5 (tab. 2), and is lower than the values characteristic for the upper continental crust (taylor & mclennan, 1985). the al2o3/tio2 ratio in clastic sedimentary rocks is used to distinguish the types of source rocks (garcia et al., 1994; andersson et al., 2004). this ratio < 14 is indicative of mafic source rocks, whereas a ratio ranging from 19–28 is characteri stic for felsic source rocks. the al2o3/tio2 ratio in the badennian -sarmatian marls of kos-i column ranges from 17.56 to 20.39 (tab. 2), suggesting that these sediments are derived from felsic source rocks. the k2o/al2o3 ratio is used as an indicator of the source composition of pelitic sedimentary rocks and is significantly different for clay minerals and feldspars. the k2o/al2o3 ratio ranging from 0–0.3 is indicative of clay minerals, and for feldspars, it ranges from 0.3–0.9 (cox et al., 1995). a k2o/al2o3 ratio of sediments > 0.5 indicates a significant content of alkali feldspar relative to other minerals in the source rocks, while a k2o/al2o3 ratio < 0.4 suggests recycling of pelitic sedimentary rocks (cox et al., 1995). in the analysed samples, this ratio is less than 0.2 (tab. 2) suggesting, therefore, they could have been derived from older pelitic sedimentary rocks. from the mineral composition of the analysed marls, it could be presumed that the potassium content in the samples originates from the presence of illite/muscovite. such a conclusion is supported by the perfect correlation of k2o and al2o3 (figure 10f) and the mineral composition of the samples (tab. 1). the na2o/k2o ratio ranges from 0.20–0.33 in the analysed samples. sodium in marls has been associated mainly with plagioclase, and in lesser amounts it could be related to the exchangeable interlayer cations of clay minerals. na2o has a perfect correlation with al2o3 in the analysed samples (fig. 10e). the degree of chemical weathering of the source rocks can be constrained by calculating the chemical index of alteration (cia) proposed by nesbitt & young (1982). according to nesbitt & young (1982), the cia values for average shale range from 70–75, and for clay minerals, illite and montmorillonites from 75.00–85.00. for the analysed marls, the cia values range from 71.81–75.01 (tab. 2), and are higher than the ucc values (< 50; taylor & mclennan, 1985). the intensity of weathering of the source rock was also deduced by the triangular al2o3-(cao+na2o)-k2o plot (after nesbitt & young 1982; 1984) with the values of the upper continental crust given by taylor & mclennan (1985), and the idealized compositions of plagioclase, k-feldspar, illite/muscovite, smectite and kaolinite/chlorite (nesbitt & young, 1984) (fig. 11). figure 11. al2o3-(cao+na2o)-k2o plot of marl samples of kos-i column (after nesbitt & young 1982; 1984) in comparison to the data for upper continental crust (ucc) given by taylor & mclennan (1985) and the idealized mineral compositions of plagioclase, k-feldspar, kaolinite, chlorite, muscovite, illite and smectite (from nesbitt & young, 1984). figure 12. rare earth element plots of marl samples from the kos-i column normalized to chondrite after taylor & mclennan (1985). g eologia c roatica grizelj et al.: palaeoecological and sedimentological characterisation of middle miocene sediments from the hrvatska kostajnica area (croatia) 167 the marl samples were plotted between the idealized compositions of smectite and illite/muscovite, implying that the source rocks underwent an intermediate degree of weathering. 5.3.2. trace elements the chemical composition and element ratios of samples critical for understanding provenance, such as la/co, th/co, th/sc, la/sc, th/cr, eu/eu*, lree/hree, σree are given in tab. 2. values of the la/co, th/co, th/sc, la/sc, th/cr, and eu/eu* ratios correspond to the values for acid (si-rich) rocks, according to cullers (1994, 2000). figure 12. represents the ree plots of samples normalized to chondrite (taylor & mclennan, 1985). all samples show lree > hree and a negative eu-anoma ly, which is in accordance with the eu/eu* ratio as indicators of the size of eu-anomalies (cox et al., 1995). the sum of ree, depending on the carbonate content, varies in the analysed samples from 36–123 ppm, while the lree/hree ratios are more uniform (lree/hree = 5.8–7.3 ppm). high lree/hree ratio indicate predominantly acid (si-rich) source rocks. figure 13. shows nb/y – zr/tio2 diagrams proposed by winchester & floyd (1977) and illustrates that all the analysed samples plot to the rhyolite field, further suggesting acid (si-rich) source rocks. 5.3.3. inferred tectonic setting la-th-sc and th-sc-zr/10 diagrams proposed by bhatia & crook (1986) were used to determine tectonic settings (fig. 14). according to these diagrams, the badennian and sarmatian marls plot close to the average composition of the upper continental crust (taylor & mclennan, 1985), and within the field of the continental island arc, representing inter-arc, fore-arc, or back-arc basin, adjacent to a volcanic-arc developed on a thick continental crust or thin continental margins (bhatia & crook, 1986). the inferred tectonic position corresponds to the fact that the pbs was one of the mediterranean basins that existed from the miocene to the pliocene (horvath & royden, 1981; royden, 1988). figure 13. nb/y vs. zr/tio2 discrimination diagram after winchester & floyd (1977) for marl samples of the kos-i column. figure 14. discrimination plots la-th-sc and th-sc-zr/10 for tectonic settings according to bhatia & crook (1986). average composition of the upper continental crust (ucc), bulk continental crust (bcc) and ocean crust (oc) after taylor & mclennan (1985) are additionally plotted. g eo lo gi a c ro at ic a geologia croatica 73/3168 5.4. biostratigraphy, palaeobiogeography, palaeoecology lithologically and according to microfossil content, three different depositional environments can be distinguished (fig. 2). 5.4.1. late badenian; lower part of the column (0.0 – 5.2 m; samples 1 – 5) silty marls dominate, followed by marls with intercalations of sand. the depositional environment varies from the distal dysoxic-anoxic shelf through a mud-dominated oxic shelf without terrigenous input to the proximal suboxic-anoxic shelf. such conditions, affected by a humid climate, caused the development of a stratified water column and low oxic conditions at the sea bed. low oxic conditions and a stratified environment were also confirmed by the presence of pyrite inclusions. these conditions are confirmed by the domination of buliminids, bolivinids and uvigerinids and the mass occurrence of globigerina bulloides and turborotalita quinqueloba (kováč et al., 2017 and references therein). based on the different genera identified, the ostracod fauna from the kos-i column can be defined as a shallow-water marine fauna. some species of the genera loxoconcha, amino­ cythere and xestoleberis tolerate lower water salinity, ranging from meso to oligohaline values. a late badenian age is determined based on the calcareous nannofossil assemblages (samples 1 and 5, fig. 2) that identifies subzone nn6c (mărunţeanu, 1999), as well as palynomorphs (samples 1 and 4, fig. 2), foraminifera (samples 1-5, fig. 2), and ostracods (sample 4, supplement tab. 2). during the late badenian, vegetation in the southernmost parts of the central paratethys was thermophilous, partly sub-humid under subtropical climatic conditions (kvaček et al., 2006; utescher et al., 2007). nevertheless, coccolith umbilico­ sphaera is typical for the warm water, oligotrophic marine environments of subtropical to temperate climate (kinkel et al., 2000; krammer et al., 2006), while small reticulofenestra are typical for oligotrophic, warm waters of lower latitudes (haq, 1980; rahman & roth, 1990). umbilicosphaera jafari in assemblage with small reticulofenestra species, noticed in sample 1, implies warmer and saltier shelf waters. this interval (fig. 2; samples 1-2) probably belongs to the beginning of the late badenian period of climate change from subtropical to warm, temperate humid climate recorded from 13.5 ma according to böhme (2003), known as the middle miocene climatic transition (mmct). occurrence of the dinocyst achomosphaera andalous­ iensis in sample 4 points to an age younger than 13.3 ma – serravallian (lourens et al., 2004). cleistosphaeridium placacan­ thum and cerebrocysta poulsenii together indicate an age no younger than the latest serravallian or earliest tortonian (jimenez-moreno et al., 2006). the ho of cerebrocysta poulsenii is calibrated against basal c5r (~11.7 ma) in italy (zevenboom, 1995). an assemblage from the lower part (sample 1) is very similar to an assemblage from the cerebrocysta poulsenii assemblage biozone of jimenez-moreno et al. (2006). they stated that the cpo zone indicates a late early serravallian age and lies within nannofossil zone nn6, as we detected here, and the bolivina–bulimina zone of the regional benthic eco-zonation of grill (1941). this zone is also a correlative of the achomosphaera andalousiensis (aan) interval zone in the mazzapiedi and cassinasco sections of northwest italy of late serravalian age (zevenboom, 1995). however, jimenezmoreno et al (2006) assigned this zone to the latest badenian (late early serravallian) in the central paratethys based on other fossils. the absence of agglutinated species with a dominance of bulimina spp. and bolivina spp. in the foraminiferal assemblage suggests a late badenian age as well (paulissen et al., 2011). the oceanic to outer neritic nematosphaeropsis labyrinthus suggests that relatively open-marine conditions existed, which is in accordance with palynofacies that indicate a dysoxic-anoxic shelf environment (fig. 6). among the foraminifera (sample 1-6), morphogroups m4 and m5 dominate. the presence of the aforementioned unicameral foraminifera also indicates a late badenian age (popescu & crihan, 2004). the main characteristic of this assemblages is its infaunal lifestyle in the muddy sediments mostly restricted to a shelf and slope environment (li & mcgowran, 1994). they prefer high productivity or a cold water environment (li & mcgowran, 1994), which is probably a consequence of a periodic influx of the cold mediterranean current that affected the climate as well as humid periods under the subtropical climate detected here. the proportions of juveniles/adults and valves/carapaces of ostracods in the sedimentary record provide an estimate of wave energy during deposition (whatley, 1988 and boomer et al., 2003). higher energy conditions lead to the removal of smaller juvenile valves and cause the disarticulation of carapaces. previous research showed that this relationship is autochthonous and characterizes the environment in which it is found when most ontogenetic stages are present in samples (whatley, 1988; boomer & eisenhauer, 2002). in all samples of kos-i column valves and a few fragments were found. in three samples (kos-i 2, 4 and 5) juvenile valves are dominant. the population structure suggested that ostracods from the kos-i column are allochthonous. most of them are transported from a high-energy environment, and deposited in a low-energy environment. resediment ostracods can be readily distinguished by examining adult to juvenile ratios. the ratio of adults and juveniles, as well as their general low frequency, suggests unfavourable conditions for the development of ostracods. finer grained particles, such as juvenile valves, are more readily transported over greater distances such as transported assemblages have cleary skewed adult to the juvenile ratio (lord et al., 2012). besides, a small portion of foraminifera morphogroups m1 and m2 also suggests reworking from the shallower, well-oxygenated environment. 5.4.2. thin layer of clayey limestone (5.70 – 6.05 m; sample 6). restricted marine conditions are inferred from the low species richness of the dinocyst assemblages, but some oceanic influence was present as indicated by the rare occurrence of impagidinium species in sample 6. according to jimenez-moreno et al. (2006), the cerebrocysta poulsenii assemblage biozone (cpo) reflects shallowing of the sea, before the emergence and erosion that led to the unconformity between the cpo and cpl zones at the badenian–sarmatian boundary. a general cooling trend appears as reflected by an increasing role of deciduous elements. sometimes it overlaps with the lowermost sarmatian, which is floristically barely distinguishable (kvaček et al., 2006). based on calcareous nannofossils, a cooling event defines the badenian/ sarmatian transition as recorded in subzone nn6c, while max. regression at the base of nn6d, close to the base of the sarmatian (galović, 2017; galović, 2020), which is in accordance with hohenegger et al. (2014). sample 6 has not been adequate for calcareous nannofossils, but this interval could apply to subzone nn6d, and stress developments recognised near the badenian/sarmatian boundary. a characteri stic feature of the period is the predominance of coniferae pointing to extrazonal mountain forests. g eologia c roatica grizelj et al.: palaeoecological and sedimentological characterisation of middle miocene sediments from the hrvatska kostajnica area (croatia) 169 the stressed marine environment is confirmed by prasinophytes. some prasinophytes are “disaster species” because of their ability to survive in a stressed environment. they have a short-lived population increase, and they are most often replaced by opportunists (harries et al., 1996, van de schootbrugge et al., 2007). the environment was probably stressful, and the assemblage was dominated by disaster species which explains the co-occurrence of prasinophyte phycomata and redeposited dinocysts. lingulodinium machaerophorum is restricted to coastal regions and regions in the vicinity of continental margins. high relative abundances can be observed in sediments near upwelling cells or below river discharge plumes or in highly stratified waters (zonneveld et al., 2013). domination of foraminifera morphogroups m3 and m6 also suggests stressful and unfavourable environmental conditions. small-sized and fragile tests of cibicidoides species and prevailing ammonia species are considered to be pioneer specimens. based on all the investigated palaeontological data the badenian/ sarmatian boundary in the kos-i column is in line with the proposed position of the boundary (fig. 2). 5.4.3. early sarmatian; upper part of the column (6.05 – 23.50 m; samples 7 – 15). marls dominate, followed by silty marls with intercalations of clayey limestone in the lower part to calcitic marls in the upper part. small, microperforate planktonic foraminifera species of the genera tenutellinata and tenuitella (indicative of the uppermost badenian – the lowermost sarmatian, according to filipescue and silye (2008)) point to the aforementioned stress conditions that occurred in paratethys at 12.73 ma (hohenegger et al. 2014), but here probably reworked from the earlier interval during the beginning of the transgression. adult badenian redeposited valves of the ostracod species bosquetina carinella, grinio­ neis haidingeri, costa sp., semicytherura filicata, olimfalunia ? plicatula, tenedocythere slebrosa, tenedocythere sulcatopunc­ tata, occur in samples 7, 8, 11 and 13. these species are very common in the badenian deposits of the north croatia basin (hajek-tadesse & prtoljan, 2011; vesel lukić & hajek-tadesse, 2017) and wider area (zorn, 2003, 2004; gross, 2006; gebhardt et al., 2009). ostracod species including: amnicythere sp. cnestocythere truncata, callistocythere cf. postvallata, aurila cf. merita, aurila cf. notata, loxocornicu­ lum hastatum, identified in the samples of the kos-i column, are known from sarmatian deposits of the wider area (gross, 2006; tóth, 2008). sample 7 has not been adequate for calcareous nannofossils nor for palynomorphs, which is supportedby aforementioned intermediate weathering and reworked shallow water ostracods and forams (fig. 2). following the lowstand in the early sarmatian, sea level rose in paratethys at ca. 12.5 ma (kováč et al., 2001) which influenced connections with the mediterranean sea and indo-pacific ocean (galović, 2017 and references therein). occurrence of the sarmatian index species nonion bogdanowiczi in sample 7 characterised the sarmatian age. an early sarmatian age is confirmed in sample 9 based on assemblages of calcareous nannofossils that identify subzone nn7a (fig. 2). the appearance of discoaster kugleri in the assemblage with rare calcidiscus pa­ taecus, helicosphaera walbersdorfensis, rhabdosphaera spp. and pontosphaera spp. characterises subzone nn7a (galović, 2019). the base of zone nn7 for paratethys is close to the fo(global) d. hexapleuros at 12.186 ma, de kaenel et al. (2017) and possibly sets the sample 9 close to 12.18 ma for paratethys (galović, 2020 and references therein) (fig. 2). according to jimenez-moreno et al. (2006), the cleis­ tosphaeridium placacanthum assemblage biozone (cpl), contains a low diversity assemblage indicating environmentally unfavourable conditions for most marine dinoflagellates. they correlate this event to the shallow depths and oscillating environmental conditions of the early sarmatian. a similar assemblage is also found in sample 9 from the kos-i column. impagidinium spp. and nematosphaeropsis labyrinthus disappeared there, indicating marginal marine environments also documented by the common occurrence of the genus batiacasphaera (gedl, 2005). high relative abundances of lingulodinium machaerophorum indicate enhanced nutrient levels and hyposaline conditions with seasonal stratifications (jimenez-moreno et al., 2006)., while increments of the coccolith r. producta, as in high latitudes (wei & thierstein, 1991), indicates periods of weaker upwelling and warmer surface water. enhanced species diver sity in zone nn7 implies a deeper and more stable environment. the increase of coccolithus pelagicus and small reticulofe­ nestra species in the upper part (fig. 2) may be interpreted as the continues influence of weaker upwelling waters that slightly induced productivity extended from the margin, where a warmer surface current along the outer shelf and upper slope appears during the winter period, similar to the present west coast of portugal (cachao & moita, 2000). 6. conclusions 1. the lithostratigraphic hrvatska kostajnica column (kos-i) represents continuous sedimentation from the late badenian to the early sarmatian. an interpretation of the depositional history was performed based on the integration of data from the sedimentological fieldwork, mineralogical, geochemical and palaeobiological (calcareous nannofossil, foraminiferas, ostracods, palynomorphs) analyses that suggest marine, offshore sedimentation. 2. the mineral composition of pelitic sedimentary rocks is common for middle miocene deposits. however, the appearance of smectite indicates possible local volcanic activity in this period, while the presence of minerals from the clinoptilolite/heulandite series indicates a local source of material. provenance analyses based on the chemical composition show that the badenian-sarmatian marls were predominantly formed by the weathering of acidic (si-rich) source rocks in the continental island arc area. 3. the investigated column was recorded from the subtropical late badenian to a warmtemperate climate of early sarmatian. a high rate of reworked microfossil species, especially foraminife ra, together with small changes in the sedimentological composition and lack of significant tectonic features make it difficult to precisely define the badenian/sarmatian boundary. the biostratigraphy based on the fossil assemblages shows that the badenian/ sarmatian boundary could be located within the column at 6.05 m from the base. 4. the position of the hrvatska kostajnica column (kos-i) at the edge of the ncb shows different attributes in depositional settings and ecological conditions than the rest of the area studied to date (the slavonian mts. and mt. medvednica). the main feature of the kos-i column, concerning fossil assemblage, reworking, can also be explained due to its position mostly detected at the edge of the basin. g eo lo gi a c ro at ic a geologia croatica 73/3170 acknowledgement this study was co-financed by the project interreg ipa cbc croatia-bosnia and herzegovina-montenegro 2014 – 2020 “safearth” (transnational advanced management of land use risk through landslide susceptibility maps design). we are very grateful to stjepan ćorić (geological survey of austria) and anonymous reviewer for their valuable and helpful reviews. references avanić, r., kovačić, m., pavelić, d., miknić, m., vrsaljko, d., bakrač, k. & galović, i. (2003): the midle and upper miocene facies of mt. medvednica (northern croatia).– in: vlahović, i. & tišljar, j. (eds.): evolution of depositional environments from paleozoic to the quarternary in the karst dinarides and the pannonian basin, field trip guidebook, 22nd ias meeting of sedimentology. institute of geology, zagreb, 167–172. avanić, r, kovačić, m., pavelić, d. & peh, z. (2018): the neogene of hrvatsko zagorje.– in: tibljaš, d., horvat, m., tomašić, n., mileusnić, m. & grizelj, a. (eds.): 9th mid-european clay conference, zagreb, conference book field trip guide book, croatian geological society, zagreb, 128–129. andersson, p.o.d., worden, r.h., hodgson, d.m. & flint, s. (2004): provenance evolution and chemostratigraphy of a palaeozoic submarine fan-complex: tanqua karoo basin, south africa.– marine petrol geo, 21, 555–577. doi: 10.1016/j. marpetgeo.2004.01.004 bakrač, k., koch, g. & sremac, j. (2012): middle and late miocene palynological biozonation of the south-western part of central paratethys (croatia).– geol. croat., 65/2, 207–222. doi: 10.4154/gc.2012.12 bhatia, m.r. & crook, k.a.w. (1986): trace element characteristics of greywackes and tectonic setting discrimination of sedimentary basins. contrib.– mineral petr., 92, 181–193. böhme, m. (2003): the miocene climatic optimum: evidence from ectothermic vertebrates of central europe.– palaeogeogr. palaeoclimatol. palaeoecol., 195, 389–401. doi: 10.1016/s0031-0182(03)00367-5 bohn-havas, m. & zorn, i. (2002): biostratigraphic correlation of planktonic gastropods in the neogene of the central paratethys. bulletin t. cxxv. de l’académir serbe des sciences et des arts, classe des sciences mathématiques et naturelles.– sciences naturelles sci. naturelles, 41, 199–207. boomer, i. & eisenhauer, g. (2002): ostracod faunas as palaeoenvironmental indicators in marginal marine environments.– in: holmes, j.a. & chivas, a.r. (eds.): the ostracoda: applications in quaternary research. geophysical monograph, 131, american geophysical union, washington, dc. 135–149. doi: 10.1029/131gm07 boomer, i. horne, d.j. & slipper, i. (2003): the use of ostracodes in paleo-environmental studies, or what can you do with an ostracod shell?– the palaeontological society papers, 9, 153–180. bošnjak, m., sremac, j., vrsaljko, d., aščić, š. & bosak, l. (2017): the miocene ‘pteropod event’ in the sw part of the central paratethys (medvednica mt., northern croatia).– geol. carpath., 68/4, 329–49. doi: 10.1515/geoca-2017-0023 brlek, m., špišić, m., brčić, v., mišur, i., kurečić, t., miknić, m., avanić, r., vrsaljko, d. & slovenec, d. (2016): mid-miocene (badenian) transgression on mesozoic basement rocks in the mt. medvednica area of northern croatia.– facies, 62/3, 1–21. doi: 10.1007/s10347-016-0470-z. brlek, m., kutterolf, s., gaynor, s., kuiper, k., belak, m., brčić, v.,holcova, k., wang, k., bakrač, k., hajek-tadesse, v., mišur, i., horvat, m., šuica, s. & schaltegger, u. (2020): miocene syn-rift evolution of the north croatian basin (carpathian–pannonian region): new constraints from mts. kalnik and požeška gora volcaniclastic record with regional implications.– int. j. earth sci. doi: 10.1007/s00531-020-01927-4 cachao, m. & moita, m.t. (2000): coccolithus pelagicus, a productivity proxy related to moderate fronts off western iberia.– mar. micropaleontol., 39, 131–155. doi: 10.1016/s0377-8398(00)00018-9 chang, l.l.y., howie, r.a. & zussman, m.a. (1998): rock forming minerals, vol. 5b, non-silicates: sulphates, carbonates, phosphates, halides.– the geological society geol. soc., london, 383 p. chamley, h. (1989): clay sedimentology.– springer-verlag. berlin, 623 p. doi: 10.1007/978-3-642-85916-8 cicha, i., rögl, f., rupp, c. & ctyroka, j. (1998): oligocene miocene foraminifera of the central paratethys.– abhandlungen der senckenbergischen naturforschenden gesellschaft, 549, 1–153. ćorić, s., pavelić, d., rögl, f., mandic, o., vrabac, s., avanić, r., jerković, l. & vranjković, a. (2009): revised middle miocene datum for initial marine flooding of north croatian basins (pannonian basin system, central paratethys).– geol. croat., 62/1, 31–43. doi: 10.4154/gc.2009.03. cox, r., dengate, j. & cullers, r.l. (1995): the influence of sediment recycling and basement composition on evolution of mudrock chemistry in the southwestern united states.– geochim. cosmochim. acta, 59, 2919–2940. doi: 10.1016/00167037(95)00185-9 cullers, r.l. (1994): the chemical signature of suorce rocks in size fractions of holocene stream sediment derived from metamorphic rocks in the wet mountains region, colorado u.s.a.– chem. geol., 113, 327–343. cullers, r.l. (2000): the geochemistry of shales, siltstones and sandstones of pennsylvanian-permian age, colorado, usa: implications for provenance and metamorphic studies.– lithos 51, 181–203. doi: 10.1016/s0024-4937(99)00063-8 cvetković, m., matoš, b., rukavina, d., kolenković močilac, i., saftić, b., baketarić, t., baketarić, m., vuić, i., stopar, a., jarić, a. & paškov, t. (2019): geoenergy potential of the croatian part of pannonian basin: insights from the reconstruction of the pre-neogene basement unconformity.– j. maps., 15, 651–661. doi: 10.1080/17445 647.2019.16450 52 de kaenel, e., bergen, j., browning, e., blair, s. & boesiger, t. (2017): uppermost oligocene to middle miocene discoaster and catinaster taxonomy and stratigraphy in the circum north atlantic basin: gulf of mexico and odp leg 154.– j. nannoplankton research j. nano. res., 37, 215–244. de leeuw, a., bukowski, k., krijgsman, w. & kuiper, k.f. (2010): age of the badenian salinity crisis; impact of miocene climate variability on the circummediterranean region.– geology, 38/8, 715–718. doi: 10.1130/g30982.1 dumitriu, s., loghin, s., dubicka, z., melinte-dobrinescu, m.c., paruch-kulczycka, j. & ionesi, v. (2017): foraminiferal, ostracod, and calcareous nannofossil biostratigraphy of the latest badenian sarmatian interval (middle miocene, paratethys) from poland, romania and the republic of moldova.– geol. carpath., 68/5, 419–44. doi: 10.1515/geoca-2017-0028 filipescu, s. & silye, l. (2008): new paratethyan biozones of planktonic foraminifera described from the middle miocene of the transylvanian basin (romania).– geol. carpath., 59 /6, 537–44. filipescu, s., miclea, a., gross, m., harzhauser, m., zágoršek, k. & jipa, c. (2014): early sarmatian paleoenvironments in the easternmost pannonian basin (borod depression, romania) revealed by the micropalaeontological dana. – geol. carpath, 65/1, 67–81. doi: 10.2478/geoca-2014-0005 galović, i. (2020). sarmatian biostratigraphy of a marginal sea in northern croatia based on calcareous nannofossils.– mar. micropaleontol, doi.org/10.1016/j.marmicro.2020.101928. galović, i. (2003): kremični i vapnenački nanofosičli sarmatskih naslaga medvednice [siliceous and calcareous nannofossils from sarmatian beds in the mt. medvednica. – in croatian, with an english abstract].– unpubl. master thesis, faculty of science, university of zagreb, 82 p. galović, i. (2017): sarmatian calcareous nannofossil assemblages in the sw paratethyan marginal marine environments: implications for palaeoceanography and the palaeoclimate.– prog. oceanogr., 156, 209–220. doi: 10.1016/j.pocean.2017.05.011 galović, i. (2019): sarmatian (late serravallian–early tortonian) biostratigraphy: a case-study in a marginal sea.– in: bybell, l.m. (eds.): 17. ina conf.-santos, brazil. j. nano. res., 39–39. galović, i. & young, j. (2012): revised taxonomy and stratigraphy of middle miocene calcareous nannofossils of the paratethys.– micropaleontology, 58, 305–334. garcia, d., fonteilles, m. & moutte, j. (1994): sedimentary fractionations be tween al, ti, and zr and the genesis of strongly peraluminous granites.– j. geol, 102, 411–322. gebhardt, h., zorn, i. & roetzel, r. (2009): the initial phase of the earlysarmatian (middle miocene) transgression. foraminiferal and ostracod assemblages from an incised valley fill in the molasse basin of lower austria.– austrian j. earth sc., 102, 100–119. gedl, p. (2005): in situ and recycled dinoflagellate cysts from middle miocene deposits at bêczyn, carpathian foredeep, poland.– stud. geol. polon., 124, 371–394. gedl, p., peryt, d. & peryt, t.m. (2016): foraminiferal and palynological organic matter records of the upper badenian (middle miocene) deposits at anadoly (marginal part of the ukrainian carpathian foredeep basin).– geol. q., 60/2, 517–536. doi: 10.7306/gq.1300.gedl gradstein, f.m., ogg, j.g., schmitz, m.d. & ogg, g. (2012): the geologic time scale 2012.– elsevier, amsterdam, 1144 p. grill, r. (1941): stratigraphische untersuchungen mit hilfe von mikrofaunen im wiener becken und den benachbarten molasse-anteilen.– öl kohle, 37, 595–602. grizelj, a., peh, z., tibljaš, d., kovačić, m. & kurečić, t. (2017): mineralogical and geochemical characteristics of miocene pelitic sedimentary rocks from the south-western part of the pannonian basin system (croatia): implications for provenance studies.– geosci. front., 8 /1, 65–80. doi:10.1016/j.gsf.2015.11.009 gross, m. (2006): mittelmiozäne ostracoden aus dem wiener becken (badenium/sarmatium, österreich).– österr. akad. wissenschaft., schriften reihe der erdwiss. komm. sonderbd, wien, 1, 1–224. hajek-tadesse, v. & prtoljan, b. (2011): badenian ostracoda from the pokupsko area (banovina, croatia).– geol. carpath., 62, 447–461. doi: 10.2478/v10096-0110032-9 hajek-tadesse, v., belak, m., sremac, j., vrsaljko, d. & wacha, l. (2009): lower miocene ostracods from the sadovi section (mt. požeška gora, croatia).– geol. carpath., 60/3, 251–262. g eologia c roatica grizelj et al.: palaeoecological and sedimentological characterisation of middle miocene sediments from the hrvatska kostajnica area (croatia) 171 haq, b.u. (1980): biogeographic history of miocene calcareous nannoplankton and paleooceanography of the atlantic ocean.– micropaleontology, 26, 414–443. harries, p.j., kauffman, e.g. & hansen, t.a. (1996): models for biotic survival following mass extinction.– in: hart, m.b. (eds.): biotic recovery from mass extinction events. geol. soc. london. special publications, 102, 41–60. doi: 10.1144/gsl.sp.1996.001.01.03 hartman, g. & puri, h.s. (1974): summary of neontological and palaeontological classification of ostracoda.– mitt. hamburg. zool. mus. inst., 70, 7–73. harzhauser, m. & piller, w.e. (2007): benchmark dana of a changing sea – paleogeography, paleobiogeography and events in the central paratethys during the miocene.– paleogeogr. aleoclimatol. paleoecol., 253, 8–31. high score plus, version 4.5 (4.5.0.22741) (2016): panalytical b.v.. almeo, the netherlands. hilgen, f.j., lourens, l.j., van dam, j.a. & ogg, j.g. (2012): the neogene period.– in: gradstein, f.m., schmitz, m.d. & ogg, g.m. (eds.): the geologic time scale 2012. vol. 2. elsevier, amsterdam, 923–978. doi: 10.1016/b9780-444-59425-9.00029-9 hohenegger, j., ćorić, s. & wagreich, m. (2014): timing of the middle miocene badenian stage of the central paratethys.– geol. carpath., 65, 55–66. doi: 10.2478/geoca-2014-0004 horne, d.j., cohen, a. & martens, k. (2002): taxonomy, morphology and biology of quaternary and living ostracoda.– in: holmes, j.a. & chivas, a.r. (eds.): the ostracoda. applications in quaternary research. geophys. monograph ser., 131, 5–6. doi: 10.1029/131gm02 horváth, f. & royden, l.h. (1981): mechanism for the formation of the intracarpathian basins: a review.– earth sci. reviews, 3–4, 307–316. jackson, m.l. (1956): soil chemical analysis – advanced course. medison. wisconsin wisc., published by the author, 894 p. jiménez-moreno, g., head, m.j. & harzhauser, m. (2006): early and middle miocene dinoflagellate cyst stratigraphy of the central paratethys, central europe.– j. micropalaeontol., 25, 113–139. doi: 10.1144/jm.25.2.113 jovanović, č. & magaš, n. (1986a): osnovna geološka karta sfrj 1:100000, tumač za list kostajnica [basic geological map of sfry, 1:100000, geology of the kosta­ jnica sheet – in croatian].– savezni geološki zavod, beograd, 46 p. jovanović, č. & magaš, n. (1986b): osnovna geološka karta m 1:100.000, list kostajnica [basic geological map of sfry, 1:100000. kostajnica sheet – in croatian].– savezni geološki zavod, beograd. kinkel, h., baumann, k.h. & cepek, m. (2000): coccolithophores in the equatorial atlantic ocean: response to seasonal and late quaternary sueface water variability.– mar. micropaleontol., 39, 87–112. doi: 10.1016/s0377-8398(00)00016-5 kováč, m., andreyeva-grigorovich, a., bajraktarević, z., brzobohatý, r., filipescu, s., fodor, l., harzhauser, m., nagymarosy, a., oszczypko, ni, pavelić, d., rögl, f., saftić, b., sliva, l. & studencka, b. (2007): badenian evolution of the central paratethys sea: paleogeography, climate and eustatic sea-level changes.– geol. carpath., 58/6, 579–606. kováč, m., halásová, e., hudáčková, n., holcová, k., hyžný, m., jamrich, m. & ruman, a. (2018): towards better correlation of the central paratethys regional time scale with the standard geological time scale of the miocene epoch.– geol. carpath., 69/3, 283–300. doi: 10.1515/geoca-2018-0017 kováč, m., hudáčková, n., halásová, e., kováčová, m., holcová, k., oszczypko-clowes, m., báldi, k., less, g., nagymarosy, a., ruman, a., klučiar, t. & jamrich, m. (2017): the central paratethys palaeoceanography: a water circulation model based on microfossil proxies, climate, and changes of depositional environment.– acta geol. slovaca, 9/2, 75–114. kováč, m., nagymarosy, a., holcová, k., hudáčková, n. & zlinská, a. (2001): paleogeography, paleoecology and eustasy: miocene 3rd order cycles of relative sea-level changes in the western carpathian north pannonian basins.– acta geol. hung., 44, 1–45. kovačić, m., horvat, m., pikija, m. & slovenec, d. (2011): composition and provenance of neogene sedimentary rocks of dilj gora mt. (south pannonian basin, croatia).– geol. croat., 64/2, 121–132. krammer, r., baumann, k.-h. & henrich, r. (2006): middle to late miocene fluctuations in the incipient benguela upwelling system revealed by calcareous nannofossils assemblages (odp site 1087a).– palaeogeogr. palaeoclimatol. palaeoecol., 230, 319–334. doi:10.1016/j.palaeo.2005.07.022 kvaček, z., kováč, m., kovar-eder, j., doláková, n., jechorek, h., parashiv, v., kováčová, m. & sliva, l. (2006): miocene evolution of landscape and vegetation in the central paratethys.– geol. carpath., 57/4, 295–310. li, q. & mcgowran, b. (1994): evolutionary morphologicalchanges in the new genus duoforisa: implication forclassification and habitat of unilocular foraminifera.– alcheringa, 18, 121–134. lippmann, f. (1973): sedimentary carbonate minerals.– springer – verlag, berlin, 228 p. doi: 10.1007/978-3-642-65474-9 lord, a.r., boomer, i., brouwers, e. & whittaker, j.e. (2012): ostracod taxa as palaeoclimate indicators in the quaternary.– dev quat sci., 17, 37–45. doi: 10.1016/b978-0-444-53636-5.00003-2 lourens, l., hilgen, f., shackleton, n.j., laskar, j. & wilson, d. (2004): the neogene period.– in: gradstein, f., ogg, j. & smith, a. (eds.): a geological time scale 2004. cambridge univ. press, cambridge, u.k., 409–440. doi: 10.1017/cbo9780511536045.022 mandic, o., de leeuw, a., bulić, j., kuiper, k.f., krijgsman, w. & jurišićpolšak, z. (2012): paleogeographic evolution of the southern pannonian basin: 40ar/39ar age constraints on the miocene continental series of northern croatia.– int. j. earth sci., 101, 1033–1046. doi: 10.1007/s00531-011-0695-6. mandic, o., hajek-tadesse, v., bakrač, k., reichenbacher, b., grizelj, a. & miknić, m. (2019a): multiproxy reconstruction of the middle miocene požega palaeolake in the southern pannonian basin (ne croatia) prior to the badenian transgression of the central paratethys sea.– palaeogeogr. palaeoclimatol. palaeoecol., 516, 203–219. doi:10.1016/j.palaeo.2018.12.003 mandic, o., rundić, lj., ćorić, s., pezelj, d., theobalt, d., sant, k. & krijgsman, w. (2019b): age and mode of the middle miocene marine flooding of the pannonian basin – constraints from central serbia.– palaios, 34, 71–95. doi: 10.2110/palo.2018.052 mandic, o., sant, k., kallanxhi, m.-e., ćorić, s., theobalt, d., grunert, p., de leeuw, a. & krijgsman, w. (2019c): integrated bio-magnetostratigraphy of the badenian reference section ugljevik in southern pannonian basin implications for the paratethys history (middle miocene, central europe).– glob. planet. change, 172, 374–395. doi: 10.1016/j.gloplacha.2018.10.010 marković, f. (2017): miocenski tufovi sjevernohrvatskoga bazena [miocene tuffs from north croatian basin – in croatian, with an english abstract].– unpubl. master thesis, faculty of science, university of zagreb, 174 p. marković, s. (2002): hrvatske mineralne sirovine [croatian mineral resources – in croatian].– institute of geology, zagreb, 543 p. martini, e. (1971): standard tertiary and quaternary calcareous nannoplankton zonation.– in: farinacci, a. (ed.): proceedings of the 2 plank. conf., roma, 739–785. mărunţeanu, m. (1999): lithoand biostratigraphy (calcareous nannoplankton) of the miocene deposits from the outer moldavides.– geol. carpath., 50, 313–324. mclennan, s.m. (1993): weathering and global denudation.– the journal of geology, 101, 295–303. doi: 10.1086/648222 moore, p.d., webb, j.a. & collinson, m. (1991): pollen analysis (second edition).– blackwell sci. publication. london, 216 p. müller, g., irion, g. & foerstner, u. (1972): formation and diagenesis of inorganic ca-mg carbonates in the lacustrine environment.– naturwissenschaften, 59/4, 158–164. doi: 10.1007/bf00637354 murray, j.w. (2006): ecology and applications of benthic foraminifera.– cambridge university press, cambridge, uk, 426 p. doi: 10.1017/cbo9780511535529 nesbitt, h.w. & young, g.m. (1982): early proterozoic climates and plate motions inferred from majorelement chemistry of lutites.– nature, 299, 715–717. nesbitt, h.w. & young, g.m. (1984): prediction of some weathering trends of plutonic and volcanic rocks based on thermodynamic and kinetic considerations.– geochim. et cosmochim. ac., 48, 1523–1534. doi: 10.1016/0016-7037(84)90408-3 pamić, j., mckee, e. h., bullen, t. & lanphere, m.a. (1995): tertiary volcanic rocks from southern panonnian basin, croatia.– int. geol. rev., 37, 259–283. paulissen, w., luthi, s., grunert, p., čorić, s. & harzhauser, m. (2011): integrated high-resolution stratigraphy of a middle to late miocene sedimentary sequence in the central part of the vienna basin.– geol. carpath., 62/2, 155–169. doi: 10.2478/v10096-011-0013-z. pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.– basin res., 13, 359–376. doi: 10.1046/j.0950-091x.2001.00155.x pavelić, d. & kovačić, m. (1999): lower miocene alluvial deposits of the požeška mt. (pannonian basin, northern croatia): cycles, megacycles and tectonic implications.– geol. croat., 52, 67–76. pavelić, d. & kovačić, m. (2018): sedimentology and stratigraphy of the neogene rift-type north croatian basin (pannonian basin system, croatia): a review.– mar. petrol. geol., 91, 455–469. doi: 10.1016/j.marpetgeo.2018.01.026 pavelić, d., miknić, m. & sarkotić šlat, m. (1998): early to middle miocene facies succession in lacustrine and marine environments on the southwestern margin of the pannonian basin system.– geol. carpath., 49, 433–443. pdf-4/minerals (2020): international centre for diffraction data. sn: mind 2001334545. peryt, d., gedl, p. & peryt, t.m. (2014): foraminiferal and palynological records of the late badenian (middle miocene) transgression in podolia (shchyrets near lviv, western ukraine).– geol. q., 58/3, 465–84. doi: 10.7306/gq.1195. popescu, g. & crihan, i.m. (2004): contribution to the knowledge of the calcareous unicameral foraminifera from the middle miocene of romania.– acta palaeontol. rom., 4, 403–421. popescu, g. & crihan, i.m. (2005a): middle miocene foraminifera from romania: order buliminida, part i.– acta palaeontol. rom., 5, 379–96. popescu, g. & crihan, i.m. (2005b): middle miocene foraminifera from romania: order buliminida, part ii.– acta palaeontol. rom., 5, 397–412. g eo lo gi a c ro at ic a geologia croatica 73/3172 popescu, g. & crihan, i.m. (2008): contributions to the knowledge of the rotaliiform foraminifera from the marine middle miocene deposits from romania.– acta palaeontol. rom., 6/4, 287–324. popescu, g. & crihan, i.m. (2011): middle miocene globigerinas of romania.– acta paleontol. rom., 7, 291–314. doi: 10.1016/j.bcp.2004.07.023. rahman, a. & roth, p.h. (1990): late neogene paleoceanography and paleoclimatology of the golf of aden region based on calcareous nannofossils.– paleoceanography, 5, 91–107. rao, p.c. (1996): modern carbonates, tropical, temperate, polar. introduction to sedimentology and geochemistry.– university of tasmania, tasmania, 206 p. royden, l.h. (1988): late cenozoic tectonics of the pannonian basin system.– in: royden l.h. & horvath, i.f. (eds.): the pannonian basin. a study in basin evolution. aapg memoir, tulsa, 45, 27–48. royden, l.h., horvath, f., nagymarosy, a. & stegena, l. (1983): evolution of the pannonian basin system 2, subsidence and thermal history.– tectonics, 2, 91–137. doi: 10.1029/tc002i001p00091 schmidt, r.r. (1978): calcareous nannofossils.– in: zachariasse, w.j., riedel, w.r., sanfilippo, a., schmidt, r.r., brolsma, m.j., schrader, h.j., gersonde, r. drooger, m.m. & broekman, j.a. (eds.): micropalaeontological counting methods and techniques-an expercise on an eight metres section of the lower pliocene of capo rossello, sicily. utrecht micropalaeontological bulletins, utrecht: schotanus and jens, 241–265. schütz, k., harzhauser, m., rögl, f., ćorić, s. & galović, i. (2007): foraminiferen und phytoplankton aus dem unteren sarmatium des südlichen wiener beckens (petronell, niederösterreich).– jahrbuch der geologischen bundesanstalt, 147, 449–488. schultz, l.g. (1964): quantitative interpretation of mineralogical composition from x-ray and chemical data for the pierre shale.– u. s. geological survey professional paper, 391–c, 31 p. shamrock, j.l., munoz, e.j. & carter, j.h. (2015): an improved sample preparation technique for calcareous nannofossils in organic–rich mudstones.– j. nannoplankton research, 35, 101–110. silye, l. (2015): sarmatian foraminiferal assemblages from southern transylvanian basin and their significance for the reconstruction of depositional environments.– presa universitară clujeană, cluj, 228 p. steininger, f.f., müller, c. & rögl, f. (1988): correlation of central paratethys, eastern paratethys, and mediterranean neogene stages.– in: royden, l.h. & horvath, f. (eds.): the pannonian basins. a study in basin evolution. am. assoc. petrol. geol. mem., 45, 79–87. taylor, s.r. & mclennan, s.m. (1985): the continental crust: its composition and evolution.– blackwell, oxford, 312 p. tišljar, j. (2001): carbonate and evaporite sedimentology.– institut za geološka istraživanja, zagreb, 375 p. tóth, e. (2008): sarmatian (middle miocene) ostracod fauna from. zsámbék basin, hungary.– geol. pannonica, 36, 101–151. tóth e., görög, a., lécuyer, c., moissette, v.b. & monostori, m. (2010): palaeoenvironmental reconstruction of the sarmatian (middle miocene) central paratethys based on the palaeontological and geochemical analyses of foraminifera, ostracods, gastropods and rodents.– geol. mag., 147/2, 299–314. tyson, r.v. (1995): sedimentary organic matter. organic facies and palynofacies.– chapman and hall, london, 615 p. doi: 10.1007/978-94-011-0739-6 utescher, t., djordjevic-milutinovic, d., bruch, b. & mosbrugger, v. (2007): climate and vegetation changes in serbia during the last 30 ma.– palaeogeogr. palaeoclimatol. palaeoecol., 253, 139–150. doi:10.1016/j.palaeo.2007.03.037 van de schootbrugge, b., tremolada, f., rosenthal, y., bailey, t.r., feist-burkhardt, s., brinkhuis, h., pross, j., kent, d.v. & falkowski, p.g. (2007): end-triassic calcification crisis and blooms of organic-walled “disaster species”.– palaeogeogr. palaeoclimatol. palaeoecol., 244, 126–141. doi:10.1016/j.palaeo.2006.06.026. van morkhoven f.p.c.m. (1963): post-palaeozoic ostracoda. their morphology, taxonomy and economic use. vol. ii. generic descriptions.– elsevier publ. co., amsterdam/london/new york, 1–478. vesel lukić, m. & hajek tadesse, v. (2017): badenian ostracods from požeška gora and papuk mts.– in: horvat, m. & wacha, l. (eds.): 7th international workshop neogene of central and south-eastern europe, zagreb, croatian geological society, 73–74. weaver, c.e. (1989): clays, muds, and shales.– elsevier, amsterdam, 721 p. wei, w. & thierstein, h. r. (1991): upper cretaceous and cenozoic calcareous nannofossils of the kerguelen plateau (southern indian ocean) and prydz bay (east anatarctica).– in: barron, j. & larsen, b. (eds.): proceedings of the ocean drilling program, scientific results, college station, tx (ocean drilling program), 119, 467-493. doi: 10.2973/odp.proc.sr.119.165.1991 whatley, r.c. (1988): population structure of ostracods: some general principles for the recognition of palaeoenvironments.– in: de deckker, p., colin, j.p. & peypouquet, j.p. (eds.): ostracoda in the earth sciences. elsevier, amsterdam, 245–256. winchester, j.a. & floyd, p.a. (1977): geochemical discrimination of different magma series and their differentiation products using immobile elements.– chem. geol., 20, 325–343. doi: 10.1016/0009-2541(77)90057-2 wood, g.d., gabriel, a.m. & lawson, j.c. (1996): palynological techniques: processing and microscopy.– in: jansonius, j. & mcgregor, d.c. (eds.): palynology: principles and applications. am. assoc. stratigr. palynol. found., 1, 29–50. vrsaljko, d., pavelić, d., miknić, m., brkić, b., kovačić, m., hećimović, i., hajek-tadesse, v., avanić, r. & kurtanjek, n. (2006): middle miocene (upper badenian/sarmatian) palaeoecology and evolution of the environments in the area of medvednica mt., (north croatia).– geol. croat., 59/1, 51–63. zevenboom, d. (1995): dinoflagellate cysts from the mediterranean late oligocene and miocene.– unpubl. phd thesis, university of utrecht, utrecht, 221 p. zonneveld, k.a.f., marret, f., versteegh, g.j.m., bogus, k., bonnet, s., bouimetarhan, i., crouch, e., de vernal, a., elshanawany, r., edwards, l., esper, o., forke, s., grøsfjeld, k., henry, m., holzwarth, u., kielt, j.f., kim, s., ladouceur, s., ledu, d., chen, l., limoges, a., londeix, l., lu, s.h., mahmoud, m.s., marino, g., matsouka, k., matthiessen, j., mildenhal, d.c., mudie, p.j., neil, h. l., pospelova, v., qi, y., radi, t., richerol, t., rochon, a., sangiorgi, f., solignac, s., turon, j. l., verleye, t., wang, y., wang, z. & young, m. (2013): atlas of modern dinoflagellate cyst distribution based on 2405 data points.– rev. palaeobot. palynol., 191, 1–197. doi: 10.1016/j.revpalbo.2012.08.003 zorn, i. (2003): ostracoda from the gaindorf formation (middle miocene, lower badenian) of mühlbach (molasse basin, lower austria).– ann. naturhist. mus. wien 104 a, 77–84. zorn, i. (2004): ostracoda from the lower badenian (middle miocene) grund formation (molasse basin, lower austria).– geol.carpath, 55/2, 179–189. g eologia c roatica grizelj et al.: palaeoecological and sedimentological characterisation of middle miocene sediments from the hrvatska kostajnica area (croatia) 173 supplement table 1. distribution of foraminifera in samples from the sedimentary kos-i column. foraminifera kos-i 1 2 4 5 6 7 8 9 11 13 15 benthic amphimorphina hauerina (neugeboren) x x x x x ammonia vienensis (d'orbigny) x x ammonia pseodobeccarii putrja x x anomalinoides cf. badenensis (d'orbigny) x asterigerinata planorbis (d'orbigny) x x astrononion perfossum clodius x x articulina sp. x x baggina arenaria (karrer) x x x x x x bolivina antiqua d'orbigny x x x bolivina dilatata reuss x x x x x x x x bolivina ex gr. pokorny cicha & zapletalova x x bolivina moldavica didkowski x x x x x bolivina granensis cicha & zapletalova x x x x x bolivina fastigia cushman x x bolivina moravica cicha & zapletalova x x bolivina papulata cushman x x bolivina pseudoplicata heron-allen & earland x x x x x x x bolivina pokornyi cicha&zapletalova x x x bolivina sagittula didkowski x x x x x x bolivina sarmatica didkowski x x x bolivina plicatella cushman x x bolivina striatula cushman x x x x bolivina nisporenica didkovski x x bulimina buchiana d'orbigny x x bulimina elongata longa d'orbigny x x x bulimina gutsulica livental x x bulimina subulata cushman&parker x x chilostomella ovoidea reuss x x cibicidoides ungerianus (d'orbigny) x x x cursina porocostata popescu&crihan x x elphidium cf. excavatum (terquem) x x x elphidium cf. subumbilicatum czjzek x x x x elphidium crispum (linne) x elphidium ex gr. hauerinum (d'orbigny) x x x elphidium reussi marks x x elphidium grilli papp x x x elphidium fichtelianum d'orbigny x x x x elphidium perscitum serova x elphidium macellum tumidocamerale bogdanowicz x x x elphidium incertum williamson x x x x x elphidium macellum (fichtel & moll) x x x x x elphidium joukovi serova x x elphidiella vignaeuxi (caralp&julius) x x x x x elphidiella artifex (serova) x favulina hexagona (williamson) x x x fissurina marginata (montagu) x x fissurina severantoni popescu x x oolina globosa (montagu) x x fursenkoina sarmatica (venglinski) x x g eo lo gi a c ro at ic a geologia croatica 73/3174 foraminifera kos-i 1 2 4 5 6 7 8 9 11 13 15 benthic fursenkoina acuta (d'orbigny) x x globobulimina pupoides (d'orbigny) x x globobulimina pyrula (d'orbigny) x x globulina gibba d'orbigny x x guttulina communis d' orbigny x hanzawaia crassiseptata (luczkowska) x x x heterolepa dutemplei (d'orbigny) x x x laevidentalina elegans (d'orbigny) x x lenticulina austriaca (d'orbigny) x x lenticulina inornata (d'orbigny) x lenticulina calcar (linne) x lobatula lobatula (walter & jacob) x x x x x x x loxostomina digitalis (d'orbigny) x neugeborina longiscata (d'orbigny) x x nonion bogdanowiczi voloshinova x nonion biporus krashenninikov x x oolina globosa (montagu) x x palliolatella sp. x x pappina neudorfensis (toula) x x x x x planularia moravica (karrer) x x x x porosolenia tibiscens popescu x porosononion martkobi (bogdanowicz) x x x pseudotriloculina consobrina (d'orbigny) x x x sigmavirgulina tortuosa (brady) x siphonodosaria consobrina (d'orbigny) x x x x spirosigmoilinita tenuis (czjzek) x spirorutilus carinatus (d'orbigny) x x uvigerina brunensis karrer x x x uvigerina pygmoides papp & turnovsky x x uvigerina semiornata d'orbignyi x x x x uvigerina venusta franzenau x valvulineria complantata (d'orbigny) x x planktonic globigerina bulloides d'orbigny x x x globigerina cf. subcretacea lomnicki x x globigerina conncina reuss x x globigerina diplostoma reuss x x x globigerina praebulloides blow x x x globigerina tarchanensis (subbotina & chutzieva) x x x globigerina cf. lentiana rogl x x globigerinella regularis (d'orbigny) x x x x globigerinita glutinata (egger) x x x x globigerinoides apertasuturalis (jenkins) x x globigerinoides quadrilobatus (d'orbigny) x x x x x x globigerinoides sacculifer (brady) x globigerinoides trilobus (reuss) x x x x x globoquadrina altispira (cushman & jarvis) x ? x globorotalia bykovae (aisenstat) x x x globorotalia cf. scitula brady x x globoturborotalita decoraperta x globoturborotalita druryi akers x x g eologia c roatica grizelj et al.: palaeoecological and sedimentological characterisation of middle miocene sediments from the hrvatska kostajnica area (croatia) 175 supplement table 2. distribution of the ostracod species within the samples of the kos-i succession. ostracods kos-i 1 2 4 5 7 8 11 13 15 aurila cf. notata (reuss) x x x aurila cf. merita zalányi x aurila sp. x x x x x x x x amnicythere sp. x bosquetina carinella (reuss) x butonia sp. x x callistocythere cf. postvallata pietrzeniuk x x x x x x callistocythere canaliculata (reuss) x x x cnestocythere sp. x x cnestocythere truncata (reuss) x x costa sp. x grinioneis haidingeri (reuss) x x x loxoconcha sp. x x loxocorniculum cf. schmidi (cernajsek) x loxocorniculum hastatum (reuss) x x olimfalunia ? plicatula (reuss) x paracytheridea triquetra (reuss) x semicytherura filicata (schneider) x semycytherura cf. alata (linenklaus) x x x tenedocythere slebrosa (uliczny) x tenedocythere sp. x x tenedocythere sulcatopunctata (reuss) x xestoleberis glaberscens (reuss) x x x x xestoleberis sp. x x x x foraminifera kos-i 1 2 4 5 6 7 8 9 11 13 15 planktonic globoturborotalita woodi (jenkins) x x x jenkinsella mayeri (cusman&ellisor) x orbulina bilobata d'orbigny x x orbulina suturalis bronnimann x x x x x x orbulina universa d'orbigny x x x paragloborotalia siakensis (leroy) x x x teniutellinata pseudoedita (subbotina) x x x tenuitella clemenciae (bermudez) x x x x tenuitella selleyi li, radford & banner x x x x tenuitellinata angustiumbilicata (bolli) x tenuitellinata juvenilis bolli x x x x turborotalita quinqueloba (natland) x x x x x x velapertina indigena luczkowska x x x 2019 | 72 / special issue | 1–1 | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society dear colleagues, it is our pleasure to present to you a selection of papers from the 6th international conference on geology resources management and sustainable development (icgrmsd2018) held in beijing, china, on december 27-28, sponsored by two organizations: hubei zhongke geology and environment technology service centre and the school of energy resources, china university of geosciences (beijing). in china, geological science is the state’s premier research area which forms part of the government planning and environment strategy. over one hundred scholars from china have joined us and presented their latest research, reporting on geophysical, geochemical, and geospatial data in the conference. the scientific content of the conference spanned 10 topics including: (1) management of geological and mineral resources and sustainable development; (2) safety engineering and evaluation of geological resources; (3) geological resource management and environmental economic evaluation; (4) land resource management and sustainable development; (5) development, planning and management of tourism resources; (6) evaluation of the value of geological relics, mining parks 6th international conference on geology resources management and sustainable development (icgrmsd2018) doi: 10.4154/gc.2019.30 and geoparks; (7) mine geological environment protection, restoration and control and mine geological hazard prevention; (8) investment and operation management of mining enterprises; (9) the development and management of the resource industry; (10) investment and operation management of geological prospecting units and mining enterprises. the 6th international conference on geology resources management and sustainable development (icgrmsd2018) received over 200 papers and chose 11 of the most suitable and outstanding ones to publish in geologia croatica, which elaborates on almost all the mentioned topics covered at the conference. additionally, this special issue tries hard to represent both the traditional and new methods in geological research. some of the new research studies dealing with the application of innovative technologies and their application in china for geological research are also exhibited within it. we wish to express our gratitude to both authors and reviewers and we hope that the presented papers will be useful not only to geologists but also to other professionals as well. guangli xu, guest editor lidija galović, editor-in-chief 2019 | 72 / special issue | 33–45 | 14 figs. | 4 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society article history: manuscript received april 11, 2019 revised manuscript accepted july 17, 2019 available online december 20, 2019 keywords: qinling orogenic belt, north china block, shirenshan, geochronology, geochemistry, petrology 1. introduction qinling orogenic belt is a complex subduction-collision orogenic belt that traverses china from east to west (xu et al., 1990, 2015 and fig. 1). it was formed during several tectonic events and types of activities including subduction, collision, and the intracontinental orogeny of the yangtze plate and the north china block (pei et al., 1995; zhang et al., 1997; song et al., 2002, 2006). the qinling orogenic belt can be divided into several tectonic zones including the southern margin of the north china block, the north qinling, the south qinling, and the northern margin of the yangtze block, based on its petrology and geotectonic features (zhang et al., 2001; dong et al., 2003; wu et al., 2018). the north china block has become one of the research hotspots in recent years due to its proximity to the north qinling, complex, its composition, and multi-stage tectonic evolution. the shirenshan gneiss (the object of this paper), is located on the southern margin of the north china block. it coincides with the northern margin of the north qinling. previous studies have shown (ren et al., 2013) that it is a product of subduction of the north qinling beneath the north china block. therefore, an in-depth study of the structural geology, petrology, geochemistry, and geochronology of the shirenshan gneiss is of great importance to further current understanding of the interactions between the north qinling and the southern margin of the north geochronology, geochemistry, and tectonic significance of the shirenshan gneiss in the southern margin of the north china block wang jingya1, ren shenglian1*, dong shuwen2, li longming1, jiang dazhi3, shi yonghong1, li jiahao1, song chuanzhong1, han xu1, li zhenqiang1, and ouyang jue3 1 hefei university of technology, school of resources and environmental engineering, hefei 230009, china; (migorhappyday@126.com; ren_lotus@126.com) 2 nanjing university, school of geoscience and engineering, nanjing 230026, china 3 western university, london, school of earth sciences, ontario n6a 3k7, canada doi: 10.4154/gc.2019.21 abstract the shirenshan block is a complex geological body located in the southern margin of the north china block (ncb). from south to north, it can be divided into the taihua group migmatite, and the shirenshan gneiss and magmatic rocks. the petrographic features, tectonic setting, provenance, and geological age of the shirenshan gneiss using comprehensive field investigations, microstructural analysis, zircon u-pb radioactive dating, and geochemical analyses were investigated for this study. the petrology, geochemistry, and geochronology of the shirenshan gneiss suggests that it is mainly a felsic rock and its protolith was a high-k calc-alkaline series a-type granite. the protolith is high in sio2, al2o3, k2o, na2o, and low in cao and mgo. overall, the sr-nd isotope composition of the samples showed no significant difference, indicating that the taihua group migmatite and the shirenshan gneiss have the same source material. the shirenshan block may be partially melted from the taihua group and formed during activity of the luoluan fault. by the method of zircon dating analysis, the protolith age of the shirenshan block was determined as 1559±16ma (early proterozoic). then, the crystallization age of the syntectonic migmatite is 439.2±7.6ma, which was formed by subduction of the taihua group. during the early cretaceous (119.5±1.3ma), the shirenshan gneiss may have experienced regional migmatization and formed the zircon rims age of the yanshanian period. litho-geochemical features of the shirenshan block are similar to a1-type granites indicating that they are post-orogenic. therefore, the metamorphic deformation of the shirenshan gneiss reflects the tectonics in the southern margin of the ncb. china block. therefore, on the basis of previous studies, comprehensive field petrology and structural geology investigations were undertaken, combined with geochemical and zircon u-pb chronology, to investigate the tectonic setting and to determine the absolute age of the shirenshan gneiss. the results obtained from this research provide a foundation for further studies on the tectonic evolution of the mesozoic intracontinental orogeny in the southern margin of the north china block. the focus of previous studies in this area was on the genesis and chronology of magmatic rocks. wang et al. (1988) concluded that the shirenshan gneiss was formed by remelting processes. they also proposed that the shirenshan gneiss was an stype granite formed by repeated metasomatism-remelting of the kuanping group schist and gneiss. they suggested that evidence such as the gradual transition between the undeformed granite bodies and the surrounding gneiss, their complex mineralogy and chemical composition supports this idea. zhang et al. (1990) concluded that the shirenshan gneiss is a mixed granitic gneiss, which is a progressive granite resulting from the effects of plate collision effect. lu et al. (1995) believed that the leftward horizontal sliding of the luoluan fault zone was responsible for partial melting and the diapiric uprising of the taihua group rocks. the partial melt was then intruded into the taihua group in a “wedge-shape” and deformed together with the luoluan fault zone to form the granitic gneiss – shirenshan gneiss. although there have been several research investigations reported on the g eo lo gi a c ro at ic a geologia croatica 72 / special issue34 petrology of the shirenshan gneiss, there is still a lack of understanding of its deformation and tectonic evolution. hence, the main objective of this research work is to address this issue. 2. geological setting the shirenshan gneiss is located in nanzhao county, henan province. it is a geological body with characteristic evidence of metamorphic deformation in the shirenshan block of the luanchuan-fangcheng section (fig. 1). the shirenshan block has a surface exposure of about 2000 km2 and is structurally controlled by faults. to the north, the checun fault separates the shirenshan gneiss from the xiong’er group volcanics. to the south, it is separated from the kuanping group by the luoluan fault zone. the shirenshan block consists of granite, shirenshan gneiss and the taihua group migmatite from north to south, respectively. except for the northern granite, both the middle part of the shirenshan gneiss and the southern taihua group migmatite have experienced multiple episodes of strong deformation. they all show evidence of tectonic activities such as subduction, collision, and subsequent intracontinental orogeny in different periods. 3. sampling and petrographic studies in order to understand the deformation of the shirenshan gneiss and the taihua group migmatite, samples from these two types were collected for petrographic studies. the shirenshan gneiss samples nz11, sample nz26, and nz33 were collected from the middle of the shirenshan block. they have a medium grain size, platy granitic structure, a gneissic structure, and a local banded and eye-shaped texture. the eyeball structure is composed of flattened and elongated figure 1. geological map of the shirenshan block, north qinling (accroding to zhang et al., 1997). g eologia c roatica jingya et al.: geochronology, geochemistry, and tectonic significance of the shirenshan gneiss in the southern margin of the north china block 35 gray-white plagioclase and light-coloured red plagioclase. the content varies greatly and exhibits obvious preferred orientation. mylonitization can be commonly observed in the gneiss. the quartz is elongated, similar to a ribbon, and the feldspar is porphyroclastic. the shape of the feldspar has the characteristics of asymmetric organization, illustrating the left-lateral sliding shearing motion. sample nz11 is a felsic gneiss collected from the nanzhaocuhuang section (sampling position coordinates: n33º36’21.06”, e112º23’13.8”). it is mainly composed of quartz (50-65 vol %), feldspar (30-35 vol %), mica (10-15 vol %), and amphibole (<1vol %) (fig. 2a). quartz is fine-grained in the form of striped singlegrains and granular aggregates showing preferred orientation which is an indication of the direction of tectonic movement. plafigure 2. microstructural features of the samples. (a) nz-11; (b) nz-26; (c) nz-33; (d) nz-17; (e) nz-20; (f) nz-21 g eo lo gi a c ro at ic a geologia croatica 72 / special issue36 gioclase is fresh with polysynthetic twin development. dark minerals are mainly composed of biotite, which are distributed as fine pieces. they are also sparsely distributed and show preferred orientation and gneissic structure. sample nz26 is a biotite plagio-gneiss collected from liangshichuan (sampling position coordinates: n33º36′18.36″, e112º19′48.18″). it is mainly composed of quartz (65-70 vol %), feldspar (35-40 vol %), mica (5-10 vol %), and amphibole (<1 vol %) (fig. 2b). part of the feldspar is sericitized and characterized by irregular grain boundaries, wavy and banded extinction, and preferred orientation. dark minerals are mainly composed of biotite and a small amount of amphibole. the biotite shows a strongly preferred orientation. sample nz33 is a biotite-bearing granitic gneiss, collected from baichitan, nanzhao county, henan province (sampling location coordinates: n33º39′24.66″, e112º17′19.44″). it is mainly composed of quartz (45-50 vol %), feldspar (50-55 vol %), mica (10-15 vol %), and amphibole (<1 vol %) (fig. 2c). quartz particles are relatively uniform in size with curved grain boundaries. the feldspar particles are small, dominated by potassium feldspar, with lattice-like twin crystal development, some with sericitization. dark minerals are mainly composed of amphibole and biotite with obvious preferred orientation and a gneissic structure. the three rock samples from the shirenshan gneiss are generally from the magmatic rock structure and the minerals did not undergo obvious dynamic recrystallization except for the obvious dynamic recrystallization phenomenon and the mylonite structure in a localised deformation strip. in addition, the dark minerals have obvious orientation, and the microscopic features also show that the dark minerals did not undergo dynamic recrystallization. this indicates that the dark minerals were oriented during the rock crystallization process and are associated with the same tectonic magmatic rock, and the gneiss-like texture is protogenetic. the taihua group migmatite samples nz17, nz20, and nz21 were taken from the taihua group located in the south of the shirenshan region. these rocks show a mainly massive structure and are oriented in a northwest-southeast direction. the main rock types include banded migmatites and amphibolite-bearing gneiss, biotite plagiogneiss, and felsic granulite. quartz grains are all finegrained, irregular, lenticular, strip-like shape and sub-particleboundary migration recrystallization. the feldspar is curved crystal faces, and at the side, forming a core mantle structure. sample nz17 is a plagioclase amphibole-bearing gneiss, collected from the cuizhuang-cangfang section (sampling position coordinates: n33º35′9.42″, e112º22′30.06″). it is mainly composed of quartz (40-45 vol %), feldspar (50-55 vol %), mica (<5 vol %), and amphibole (5-10 vol %) (fig. 2d). the quartz particles are small and are distributed around a feldspar due to sub-grain dynamic recrystallization. the feldspar crystals are fresh showing polysynthetic twin development and exhibiting plastic deformation characteristics and clear subgranularization. some of the residual speckles have a core-mantle structure, which shows strong metamorphic deformation. the inner side has a creep deformation structure which is a representative of high temperature. the dark minerals are mainly composed of biotite and hornblende. the biotite is more idiomorphic than the hornblende indicating that it is crystallized later. sample nz20 is a hornblende-bearing felsic gneiss collected from yangshuzhuang village, nanzhao county, henan province (sampling location coordinates: n33°35’17.16′′, e112°19′29.94′′). it is mainly composed of quartz (40-45 vol %), feldspar (35-40 vol %), mica (<1 vol %), and amphibole (20-25 vol %) (fig. 2e). quartz is strip-shaped, the grain boundary is curved into a leaf shape, and dynamic recrystallization is dominated by boundary migration with a sub-particle form. the feldspar residuals are large, in irregular eyeball shape, with strong wavy extinction, much deformation and cracks. most of the feldspars are striped with deformation distortion. there are some albite rims around the grains along with some recrystallization at the edges of the granules. the dark mineral is mainly hornblende. sample nz21 is a biotite hornblende-bearing gneiss, collected from shimiao bay in nanzhao county, henan province (sampling location coordinates: n33°35’44.88′′, e112°19′42.6′′). it is mainly composed of quartz (30-35 vol %), feldspar (60-65 vol %), mica (510 vol %), and amphibole (10-15 vol %) (fig. 2f). quartz is with fine granules and signs of strong deformation. all of the minerals exhibit sub-particle-boundary migration recrystallization with strong wavy extinction. the feldspar is in rotating porphyritic form and the ridges are bulged and recrystallized. the biotite is strongly deformed and shows signs of bending and kinking. in general, the three rock samples from the taihua group show strong dynamic recrystallization. this is an indication that they have experienced a certain intensity of tectonic stress after crystallization. from north of the luoluan fault zone, the grain size of the rocks gradually changes from fine granular, long strips, with strong preferred orientation to coarse-grained and semi-orientated to the granite protolith. the quartz changes from elongate crystals to granular texture, and the recrystallization migrates from sub-particles to the high-temperature boundary. the feldspar gradually changes from fractured and stress textures to subgranulation, with a core-mantle structure and k-metasomatism. these characteristics indicate that under the impact of the luoluan fault zone, the intensity of deformation inside the shirenshan block gradually weakens from the south taihua group to the central shirenshan gneiss. 4. analytical methods 4.1. zircon dating analysis the single mineral separation of zircon was completed by the langfang laboratory of the hebei provincial geological prospecting bureau. after polishing, the optical and cathode fluorescence (cl) of the zircon was observed and the u-th-pb isotope analysis was carried out using la-icp-ms. the zircon u-pb dating analysis was completed in the la-icpms clean laboratory of the hefei university of technology. the laser ablation aperture was 24μm, helium was used as the carrier gas, argon was used as the compensation gas to adjust the sensitivity, and the international standard 91500 was used as the external standard. the nistsrm610 was selected as the external standard of element content. for every test, 5 samples were selected and tested twice according to standard 91500. the off-line data processing (including selection of sample and blank signals, instrument sensitivity drift correction, element content and u-th-pb isotope ratio and age calculation) was performed using the icpmsdatecal 9.0 software. detailed instrument operating conditions and data processing methods can be found in the literature (liu et al., 2010). 4.2. analysis of major and trace elements the whole-rock element analysis was carried out in the australian minerals laboratory (guangzhou) of the aussie analytical testing group. the main elements were tested by fluorescence spectrometer (xrf), from the axios instrument produced by panalytical in the netherlands. the trace elements were anag eologia c roatica jingya et al.: geochronology, geochemistry, and tectonic significance of the shirenshan gneiss in the southern margin of the north china block 37 lyzed by icp735-es in the australian minerals laboratory (guangzhou) of the aussie analytical testing group. the multielement content of the rock sample was determined by inductively coupled plasma emission spectroscopy (icp-aes) after tetracid digestion, and 33 elements were detected (for list of elements see table 2). the alkali fusion method was also adopted for rare earth element (ree) analysis. the rock sample was added to libo2 to be uniformly mixed, melted in a furnace above 1000°c, and 31 elements were detected by inductively coupled plasma mass spectrometry (icp-ms). the detection instrument used is the perkin elmer, usa production of elan 9000. 4.3. whole rock sr-nd isotopic analysis the sr-nd isotope separation test of rock samples was completed on the mc-icp-ms from the laboratory of nanjing polypeptide detection technology co., ltd. the rb-sr and sm-nd isotope separations of whole rock samples include the process of sample preparation, chemical separation, and testing. the rock powder was dried in an oven and then weighed. similar to the method of treating samples by icp-ms, the acid dissolution method was used for the dissolution of the sample. rb-sr and sm-nd isotope separation was carried out using the conventional cation exchange resin method. the type of resin used for rb-sr separation is agsow-x8, and hdehp resin was used for sm-nd separation. for detailed separation and test procedures, see liu et al. (2004). 5. results 5.1. zircon u-pb age the zircon crystals of the shirenshan gneiss are generally 50150μm in diameter in the form of elongated grains with an aspect ratio of 2:1~3:1 (fig. 3). the cl image shows that all zircons have a core-mantle structure. the core is relatively wide, generally larger than 40μm, with bright luminescence and an obvious magmatic crystallization zone. the rims are narrow, generally less than 10μm, with very few around 25μm, with weak luminescence and no obvious structure. the zircon rim and the mantle are rugged, bay-like, jagged, and some dark patches are needle-like or bay-like into the magma core and light core residual can be found in the dark patches which indicate that it is a heterogeneous metamorphic recrystallized structure. the zircon cl structure indicates that the core is part of the magmatic original zircon which was not affected by the metamorphism, and the rim is formed by the later metamorphism episode. the 206pb/238u age-weighted average of 11 analysis points from the zircon rims is 119.5±1.3ma (mswd=1.5) (table 1 and fig. 4a). the 206pb/238u age of 9 analysis points from the zircon mantle ranges from 424 to 461 ma with the weighted mean age of 439.2 ± 7.6 ma (mswd = 1.14) (table 1 and fig. 4b). in addition, the 206pb/238u age of 7 analysis points from the zircon cores is 1506ma ~ 1592ma with the weighted average age of 1559±16ma (table 1). table 1. zircon u-pb isotopic data for the samples. spot no. content (ppm) isotopic ratios isotopic ages (ma) th u pb 207pb/206pb 207pb/235u 206pb/238u 207pb/206pb 207pb/235u 206pb/238u nz-1 589 2030 42.96 0.0509 0.1291 0.0183 235 123 117 nz-2 472 1985 42.76 0.0472 0.1208 0.0184 57.5 116 118 nz-3 527 3965 81.86 0.0499 0.1282 0.0184 191 122 118 nz-4 549 2347 49.66 0.0490 0.1257 0.0185 146 120 118 nz-5 604 1982 46.91 0.0495 0.1318 0.0186 172 126 119 nz-6 379 2093 45.39 0.0507 0.1325 0.0187 228 126 120 nz-7 650 2808 60.01 0.0513 0.1335 0.0188 254 127 120 nz-8 154 1319 27.28 0.0463 0.1217 0.0190 16.8 117 121 nz-9 553 2112 46.50 0.0506 0.1342 0.0191 220 128 122 nz-10 363 1730 37.18 0.0499 0.1319 0.0191 191 126 122 nz-11 154 1208 25.45 0.0532 0.1414 0.0191 339 134 122 nz-12 204 364 122.4 0.1022 3.7389 0.2631 1665 1580 1506 nz-13 182 366 124.9 0.0970 3.6212 0.2681 1569 1554 1531 nz-14 464 691 270.3 0.0959 3.5843 0.2684 1546 1546 1532 nz-15 181 537 219.7 0.0994 3.6717 0.2728 1613 1565 1555 nz-16 271 580 197.2 0.0981 3.7342 0.2729 1589 1579 1556 nz-17 150 204 74.9 0.0973 3.7539 0.2766 1574 1583 1574 nz-18 360 505 188.4 0.0997 3.9078 0.2801 1618 1615 1592 nz-19 60.9 678 420 0.0682 0.6413 0.0680 876 503 424 nz-20 55.0 575 459 0.0544 0.5141 0.0680 387 421 424 nz-21 29.8 229 243 0.0842 0.8079 0.0698 1298 601 435 nz-22 17.8 137 181 0.0545 0.5242 0.0699 394 428 436 nz-23 21.1 147 218 0.0560 0.5445 0.0704 454 441 439 nz-24 40.7 403 328 0.0549 0.5369 0.0710 409 436 442 nz-25 29.8 290 221 0.0715 0.7043 0.0719 972 541 447 nz-26 22.4 106 242 0.0595 0.6009 0.0728 583 478 453 nz-27 32.0 275 245 0.0727 0.7396 0.0741 1006 562 461 g eo lo gi a c ro at ic a geologia croatica 72 / special issue38 5.2. major elements a geochemical study of the samples was carried out to shed some light on the provenance of the shirenshan gneiss and the taihua group (table 2). the shirenshan gneiss and taihua group migmatites are rich in silica sio2 is 69.11-75.43wt%, aluminum al2o3 is 13.41-17.81wt%, and potassium k2o is 4.05-5.29wt%, with an aluminum saturation index (a/cnk) of 1.37-1.58; which belongs to the high-k calc-alkaline series of strong aluminous granite (figs. 5, 6). in the harker diagram (fig. 7), the contents of tio2, al2o3, mgo, cao, tfe2o3, na2o, and p2o5 decrease with increasing sio2 content showing a good negative linear correlation and indicating that fractional crystallization of sideromelane, plagioclase, and apatite may have played an important role in the process of magma evolution. the rock is rich in iron and poor in magnesium. the mass fraction of tfe2o3 is 1.46-5.24wt% and the mass fraction of mgo is 0.20-1.86wt%. the ratio of tfeo/mgo is 2.54-13.39 (average 6.08 wt%); which is within the range of variation tfeo/mgo in figure 3. representative cathodoluminescence (cl) images for zircons from the sample, the open circles are spot analyses with available 206pb/238u ages. figure 4. la-icp-ms zircon u-pb isotopic dating. (a) u-pb isotopic data from the zircon rims and (b) u-pb isotopic data from the zircon mantles. figure 5. sio2-k2o diagram for the samples (peccerillo et al., 1976). figure 6. a/cnk-a/nk diagram for the samples (maniar et al., 1989). g eologia c roatica jingya et al.: geochronology, geochemistry, and tectonic significance of the shirenshan gneiss in the southern margin of the north china block 39 type a granite (king et al., 1997), and higher than the general i type (the average is 2.27) granite, the s type granite (the average is 2.38) and the m type granite (average 2.37) (king et al., 1997). in the w(tfeo)/(tfeo+mgo)-w(sio2) diagram (fig. 8), all of the samples fall into the iron region and also the area of a-type granite. from the characteristics of the main elements of the sample, there is no obvious difference between the shirenshan gneiss and the taihua group migmatite which indicates that the original rocks of the shirenshan gneiss may come from the taihua group. 5.3. trace and rare earth elements the total rare earth element (σree) content of the shirenshan gneiss and taihua group migmatite samples is between 84ppm230ppm and the content of light rare earth elements is 73ppm219ppm. the heavy rare earth elements range between 10ppm25ppm and the ratio of lree/hree is 6.41-20.07. fig. 9a shows the chondrite-normalized rare earth element distribution and the rock generally indicates lree enrichment, relative to hree which are depleted. the ratio of (la/yb)n in the shirenshan gneiss sample is 4.85-10.23 indicating that the light and heavy rare earth elements are highly fractionated. the δeu is also between 0.28 and 0.85 with an average of 0.56 showing a generally v-shaped rare earth element distribution mode with moderate eu negative anomaly. the mean value of δce is 0.97 and there is basically no ce anomaly. the (la/yb)n ratio of the taihua group is 35.08-63.42 indifigure 7. harker variation diagrams for the samples. figure 8. w(tfeo)/(tfeo+mgo)-w(sio2) diagram for the samples (frost et al., 2001). g eo lo gi a c ro at ic a geologia croatica 72 / special issue40 cating that the fractionation of light and heavy rare earth elements is weak. the eu of the rock samples shows an evident negative anomaly, and the eu/eu* is between 0.47-0.82. figure 9b illustrates the primitive mantle standardized trace element spider diagram, where the shirenshan gneiss and taihua group migmatites are rich in cs, rb, th, u, la, and other large ion lithophile elements and high field strength elements nb, ta, zr, and hf. they are also very poor in sr, p, ti, and other elements; which, is different from arc magmas. compared to the taihua group migmatite, the shirenshan gneiss is richer in th, u, zr, and hf, and depleted in ba, ce, and y where p and sr are negative anomalies indicating the presence of plagioclase in the rock as a table 2. main and trace elements geochemical test results for the samples (main elements: wt%; rare earth and trace elements: ppm). sample nz11 nz26 nz33 nz17 nz20 nz21 sio2 69.14 69.11 75.43 67.64 69.36 74.72 tio2 0.57 0.22 0.13 0.78 0.41 0.12 al2o3 13.60 17.81 13.41 15.18 14.94 13.45 tfe2o3 (total of fe2o3) 5.24 4.17 1.65 3.83 2.83 1.46 tfeo (total of feo) 4.72 3.75 1.48 3.45 2.55 1.31 mno 0.09 0.13 0.05 0.09 0.04 0.04 mgo 1.86 0.28 0.22 0.93 0.72 0.20 cao 1.48 1.07 0.56 0.82 1.76 1.03 na2o 3.09 7.08 3.70 4.02 3.87 4.06 k2o 4.05 4.84 4.98 5.29 4.87 4.52 p2o5 0.11 0.05 0.02 0.28 0.20 0.03 loi 0.51 0.30 0.36 1.03 0.64 0.67 total 99.83 100.16 100.59 100.06 99.98 100.40 a/cnk 1.58 1.37 1.45 1.50 1.42 1.40 tfeo/mgo 2.54 13.39 6.73 3.71 3.54 6.55 na2o/k2o 0.76 1.46 0.74 0.76 0.79 0.90 ba 590 580 440 780 2060 600 cr 62 6 15 10 9 13 hf 6.2 15.8 4.8 4.9 6.2 4.0 nb 20.7 65.7 39.2 25.6 20.1 27.9 ga 18.9 21.1 19.0 20.5 20.7 19.4 rb 210 122.0 280 120.5 127.0 191.5 sr 187.0 193.5 120.0 240 850 175.0 ta 1.7 2.5 5.3 1.9 2.3 2.2 th 0.88 0.47 0.97 0.82 0.57 0.45 u 5.18 0.71 14.85 2.00 4.39 5.41 y 29.1 13.8 38.8 24.5 14.4 19.4 zr 230 837 131 184 227 111 la 44.8 16.2 40.8 40.1 50.4 28.9 ce 83.8 39.2 75.7 84.2 107.0 53.7 pr 8.97 4.90 7.91 9.61 11.50 5.19 nd 34.1 20.0 27.9 37.8 42.1 17.2 sm 6.37 3.77 5.30 6.36 6.88 3.01 eu 3.15 1.64 4.29 2.25 1.30 2.11 gd 5.80 3.18 5.46 5.80 4.61 2.77 tb 0.88 0.47 0.97 0.82 0.57 0.45 dy 5.40 2.78 6.48 4.66 3.02 3.14 ho 1.05 0.54 1.31 0.87 0.51 0.66 er 3.15 1.64 4.29 2.25 1.30 2.11 tm 0.48 0.28 0.71 0.32 0.18 0.35 yb 3.12 1.85 4.72 1.92 1.18 2.46 lu 0.51 0.33 0.80 0.29 0.17 0.40 y 29.1 13.8 38.8 24.5 14.4 19.4 lree 178.68 73.06 158.51 179.7 219.3 108.5 hree 20.39 11.07 24.74 15.83 10.93 10.33 lree/hree 8.76 6.60 6.41 11.35 20.07 10.50 ∑ree 199.07 84.13 183.25 195.6 230.3 118.8 (la/yb)n 10.23 4.85 6.25 35.08 63.42 46.07 eu/eu* 0.56 0.85 0.28 0.82 0.74 0.47 ce/ce* 0.97 0.97 0.97 1.02 1.05 0.99 g eologia c roatica jingya et al.: geochronology, geochemistry, and tectonic significance of the shirenshan gneiss in the southern margin of the north china block 41 molten residual phase or a crystalline separation phase. this supports a close relationship between the source rock material of the shirenshan gneiss and the continental crust (sylvester, 1998). the large losses of p and ti indicate that the magma has undergone crystallization and separation of secondary minerals such as apatite and rutile (roberts, 1993). in addition, the rb/sr ratio of the shirenshan gneiss and taihua group migmatite samples is higher than the rb/sr ratio of the crust (0.25), indicating that the source rock material may have an argillaceous crustal protolith (sisson, 2005). in general, the shirenshan gneiss and taihua group migmatite samples show similar curve characteristics indicating that trace elements have similar geochemical behaviour and common source region properties. 5.4. sr-nd isotope in this paper, six samples from the shirenshan gneiss and taihua group migmatite were selected for sr-nd isotope analysis (table 3). there is no significant difference between the sr-nd isotopic compositions of the taihua group migmatite and the shirenshan gneiss samples. among the shirenshan gneiss samples, (87sr/86sr)i=0.71158-0.71763, εsr(t) = 61.9-62.4, (143nd/144nd)i= 0.511688-0.5122124, εnd(t)=-6.3-6.0, among the taihua group migmatite samples, (87sr/86sr)i=0.71193-0.71751, εsr(t)=61.8-62.2, (143nd/144nd)i=0.5116956-0.5123385, εnd(t)=-5.9--5.5. 6. discussion 6.1. geochronological significance in order to define the ages of multiple tectonic activity, la-icpms zircon u-pb dating was performed on the shirenshan gneiss and the weighted average age of 206pb/238u was obtained; 119.5±1.3ma and 439.2±7.6ma. some of the zircon cores are older and have a weighted average age of 1559±16 ma which represents the age of the intact rock without complete melting. it can be seen from the mineralogical characteristics and zircon age determinations (table 1) that the zircon core of the shirenshan gneiss was formed during the mesoproterozoic. this is similar to the age of the taihua group (gao et al., 2014) and indicates that the zircons of the shirenshan gneiss originated from the ancient taihua group. zircon metamorphism is relatively low and the characteristics of magma crystallization are preserved. the age of 439.2±7.6 ma in the mantle is the crystallization age of the magma after melting, which is consistent with the age of subduction of the luoluan fault zone in the south of the taihua group gneiss (ren et al., 2016). this can be attributed to partial melting of the taihua group resulting from subduction and shearing of the luoluan fault zone in the south of the taihua group. the age of the zircon rim of 119.5 ± 1.3 ma corresponds to the intrusive age of the undeformed granite on the north side of the shirenshan gneiss (wang et al., 2017). in the yanshanian period, due to regional migmatization, undeformed granite of yanshanian age invaded the north side. these results together with previous research data (ren et al., 2013) suggest that the shirenshan gneiss protolith may have originated from the ancient geological bodies around the southern margin of the north china block. subduction of luoluan fault zone from the south to the north in the late caledonian particularly caused partial melting of the taihua group on the upper plate, and then invaded the weak zone caused by the left-lateral sliding leading to the formation of homotectonic magmatic rocks. the left-lateral sliding during the plastic phase resulted in the formation of the primary surface. after the crystallization of the magma, the left-lateral sliding activity continued and formed a mylonite strip in the gneiss. during the early cretaceous period, figure 9. (a) chondrite normalized ree patterns and (b) primitive mantle normalized trace element diagrams. (normalization values after sun et al., 1989). table 3. sr-nd isotope data for the samples. sample nz11 nz26 nz33 nz17 nz20 nz21 87sr/86sr 0.711608 0.715894 0.717684 0.711963 0.715518 0.717557 (87sr/86sr)i 0.71158 0.71586 0.71763 0.71193 0.71555 0.71751 εsr (t) 61.9 62.3 62.4 61.9 62.2 61.8 143nd/144nd 0.511759 0.5117169 0.5122322 0.5120851 0.5123903 0.5117765 (143nd/144nd)i 0.511703 0.511688 0.5122124 0.512064 0.5123385 0.5116956 εnd (t) -6.0 -6.3 -6.1 -5.6 -5.5 -5.9 g eo lo gi a c ro at ic a geologia croatica 72 / special issue42 due to regional migmatization, a large number of undeformed granites intruded into the northern part of the shirenshan gneiss and experienced extensive thermal transformation. 6.2. precursor of the shirenshan gneiss pitcher (1982) classified granites into four types (i, s, m, and a) based on their differences in protolith and geochemical properties. this classification has been widely applied in the research on petrogenesis (coltiss et al., 1982; whalen et al., 1987; eby, 1990). the m-type granite parental magma is derived from subducted oceanic crust or mantle wedge melting. after extensive fractional crystallization, a series of continuous gabbro and diorite rock combinations (pitcher, 1982) were formed with geochemical properties of low rb, zr, nb, y, and ree content (whalen et al., 1987). since a/cnk<1 and this characteristic is not consistent with the characteristics of the shirenshan gneiss, the protolith is highly unlikely to be an m-type granite. the stype granite source rocks are dominated by al-rich sedimentary rocks. al supersaturation and the minerals cordierite and muscovite often occur. alternatively, s-type granites generally have lower oxygen fugacity, fe3+/(fe3++fe2+) is about 0.153 (chappell, 1999). there is no aluminium-rich mineral production in the shirenshan gneiss and the mean value of fe3+/(fe3++fe2+) is 0.53. this is obviously different from that of s-type granites. the sample shows a peraluminous feature, a/cnk>1.1, 87sr/86sr>0.705, which is not inconsistent with the geochemical characteristics of type i granites. the shirenshan gneiss has the characteristics of high silicon (sio2 content > 67.64), alkali-rich ((na2o+k2o) content > 7.14%), calcium-poor (cao content < 2.87%), and high feot/mgo ratio (>3.5). the sample data points in the na2o-k2o diagram (fig. 10) fall into the a-type granite range. furthermore, the rock is relatively rich in ree (except eu) and the large ion lithophile elements (cs, rb, th, u, la). however it is very poor in nb, ti, and hf and the other high field strength elements with a high 10000ga/al ratio >2.6, (the lower limit of the a-type granite is 2.6). these features show that the shirenshan gneiss originated from a a-type granite (figs. 11 & 12). type a granites are a product of post-collision or an intraplate environment. according to their geochemical characteristics, type a granites can be further divided into two subtypes, a1 and a2 (eby, 1992). the a1 type granite generally represents figure 10. na2o-k2o diagram of the samples, legend a, i, s type granite (collins et al., 1982). figure 11. (na2o + k2o-cao) -sio2 diagram of the samples (frost et al., 2001). figure 12. na2o + k2o and nb-10000ga/al diagram of the samples (whalen et al., 1987). g eologia c roatica jingya et al.: geochronology, geochemistry, and tectonic significance of the shirenshan gneiss in the southern margin of the north china block 43 a non-orogenic continental rift or intraplate environment. an a1 type granite source area is similar to the source area of the ocean island basalt (oib) intruding into the continental rift under the non-orogenic system or the tectonic setting related to the mantle plume and hotspot. the source rock of the a2 type granite originates from the continental crust or crust formed during underplating in a continent-continent collision or island arc environment and its characteristic element ratio is between the island arc basalt (iab) and the average continental crust (eby, 1992). since the ratio of y/nb and yb/ta is mainly controlled by the rock type in the source area, the crystallization differentiation of pyroxene, hornblende, and opaque minerals has a weak influence on the above ratio, the ratio of y/nb and yb/ta can be used to distinguish between the two types of a-type granites (eby, 1992). in the y/nb-yb/ta and ce/nb-y/nb discriminant diagrams, the sample basically falls into the a1 type granite area (fig. 13). it can be concluded here that the shirenshan gneiss has a geochemical signature of an a1 type granite. 6.3. material source and genetic model the following genetic mechanisms were proposed in the literature for the formation of a-type granites: (1) partial melting of crustal materials at low pressure and high temperature (collins et al., 1982; whalen et al., 1987; douce, 1995); (2) direct derivation from the mantle source alkali basaltic magma (eby, 1992; turner et al., 1992); and (3) a mixed product of the mantle source alkali basaltic magma and the magma formed under crust source anatexis (mingram et al., 2000; bonin, 2004). since the y-yb incompatibility is stronger than the nb and ta, the magma formed by the partial melting of the lower crust or the upper crust has a higher yb/ta and y/nb ratio than the lower crust or the upper crust (rudnick et al., 2003). the ratio of the above elements in the shirenshan gneiss is significantly lower than the ratio of the crust indicating that the genetic mechanism of partial melting of crustal material can be ruled out. previous studies have also shown that type a granite can be formed directly by fractional crystallization of mantle source basaltic magma (turner et al., 1992; douce, 1995; king et al., 1997). the intermediate-acid intrusive rocks with the same age as the shirenshan gneiss such as the taishanmiao granite and the funiu mountain granite, are common at the southern margin of the north china block (ren et al., 2013). these rocks are often rich in rb, ba, and sr, large ion lithophile elements and high field strength elements such as nb, ta, zr, and hf, and relatively low in nd isotopes, derived from the oib melt formed by the asthenosphere metasomatized lithospheric mantle (wang et al., 2019). the shirenshan gneiss is enriched with light rare earth elements, large ion lithophile elements, and high field strength elements. this is consistent with the basalt formed from the asthenosphere metasomatized lithospheric mantle (turner et al., 1992). hence, it is speculated that the shirenshan gneiss may have a close genetic relationship with the mantle-derived magma at that time. in general, crustal contamination can result in the loss of nb and ta in the magma, the enrichment of pb, and also affect the composition of the sr, nd, and hf isotopes in the rock (rudnick et al., 2003). according to gao et al. (2014), zircons in the gneiss in the shirenshan area have a negative εhf(t) value (table 4), a relatively discrete age distribution, and relatively enriched pb elements. this shows that the magma has undergone a degree of crustal contamination during the upwelling process. however, there is no loss of nb and ta in the shirenshan gneiss, which may be related to the relatively high concentration of high field strength elements and relatively weak crustal contamination in the rock source area. table 4. la-mc-icp-ms zircon hf isotope data of the shirenshan gneiss (according to gao et al., 2014). spot 176yb/177hf 176lu/177hf 176hf/177hf εhf(t) tdm1(ma) tc dm flu/hf no.1 0.013499 0.000608 0.281904 -27.9 1877 2930 -0.98 no.2 0.024122 0.001022 0.282429 -9.4 1165 1777 -0.97 no.3 0.032895 0.001364 0.282356 -12.0 1279 1942 -0.96 no.4 0.030050 0.001279 0.282241 -12.8 1309 1993 -0.96 no.5 0.012840 0.000612 0.282394 -15.9 1412 2190 -0.98 no.6 0.009096 0.0011124 0.282262 -10.6 1379 1856 -0.97 figure 13. y/nb-yb/ta and ce/nb-y/nb diagrams (eby, 1992). g eo lo gi a c ro at ic a geologia croatica 72 / special issue44 based on the above analysis, it can be concluded that the shirenshan gneiss was formed from the asthenosphere metasomatized lithospheric mantle during fractional crystallization. in addition, this set of oib-like melts were affected by a degree of crustal contamination during the magma emplacement process. 6.4. geodynamic setting type a granites have special petrogenetic significance and are only produced in a specific tectonic setting. the formation of a2 type granite is completed in a continent-continent collision environment or related to island arc magmatism; while the formation of a1 type granite occurs in a non-orogenic environment such as a continental fracture or inner plate related to an extension system (eby, 1992). the shirenshan gneiss in this study is an a1 type granite formed at 439 ma. its source area is similar to an oceanic island environment signature and is related to the taihua group migmatite. as shown in fig.15, the sample points all fall into the area of granite at the plate. the previous studies concluded that this type of magmatic activity is often associated with mantle plume or asthenosphere mantle upwelling (eby, 1992). the existing geological data indicates that the southern margin of the north china block was outwith the non-supercontinent and an ancient oceanic basin developed at the margin (cawood et al., 2013). in addition, there are no continental flood basalts in the north qinling block. it can be concluded here that the shirenshan gneiss is highly unlikely to be associated with mantle plume activity. the fracture zone of the subduction plate leads to back-arc extension and crustal thinning which can induce upwelling of the hot asthenospheric mantle forming a magma similar to oib. for example: the eastern alps (qorbani et al., 2015), mediterranean region (jolovet et al., 2015), and central mexico (ferrari, 2004). hence, we suggest that the shirenshan gneiss was formed in the following dynamic setting: prior to formation of the shirenshan gneiss, the southern margin of the north china block was in a subduction-related island arc environment. the widely exposed shirenshan gneiss is an a1 type granite and was formed in a back-arc extension environment. the geochemical characteristics of the shirenshan gneiss are similar to the geochemical characteristics of the magmatic rocks formed in relation to the fracture zone of the subduction plate in both china and around the world. both are rich in large ion lithophile elements rb, k, u, and pb and high field strength (hfs) elements nb, ta, zr, and hf from the asthenosphere metasomatized lithospheric mantle. due to the similarity of the sr-nd isotope composition of the shirenshan gneiss and the taihua group migmatite, the geochemical characteristics of the main trace elements are inherited. this indicates that the taihua group rock has the same material source as the gneiss in the middle of the shirenshan area. based on the above regional geological data and previous research, the authors believe that at the southern margin of the north china block, subduction and the strike-slip luoluan fault zone resulted in crustal thinning, asthenosphere mantle upwelling, partial melting of the taihua group rocks, and the formation of a syntectonic magma during the late caledonian period. beneath the subduction plate fault system, the intrusive fault zone along the tectonically weak zone facilitated the gneiss formation. during the early cretaceous period, due to regional migmatization, a large number of undeformed granites intruded the north side resulting in the yanshanian age. hence, the metamorphic deformation of the shirenshan gneiss is a reflection of the tectonic-magmatic activity in the shirenshan area on the southern margin of the north china block. this is of great significance for further studies on the plate edge deformation during the subduction process. 7. conclusions through a detailed study of structural geology, petrology, geochemistry, chronology, and tectonic environment of the shirenshan gneiss, the following conclusions can be drawn: (1) the protolith age of the shirenshan gneiss is 1559±16ma (early mesoproterozoic). then, it was melted under the impact of the subduction of the plate and formed an isostructure magmatite with a crystallization age of 439.2±7.6ma (late caledonian). at 119.5 ± 1.3 ma, the early cretaceous, the shirenshan gneiss may have undergone regional migmatization which results in the age of the yanshanian. (2) the shirenshan gneiss is mainly composed of biotite plagiogneiss and felsic gneiss characterized by its high sio2, al2o3, k2o, na2o, and low cao, mgo. it is a strong peraluminous highk calc-alkaline a1 granite formed in an oceanic island environment molded by the asthenosphere metasomatized lithospheric mantle under fractional crystallization with a degree of crustal contamination. (3) there is no significant difference in the main trace elements and sr-nd isotopic compositions of the samples. this indicates that the taihua group migmatite and the shirenshan gneiss have the same material source, namely the shirenshan figure 14. a granitic gneiss tectonic discrimination map. legend: volcanic arc granite (vag), syn-tectonic collision granite (syn-colg), within plate granite (wpg) and ocean ridge granite (org) (pearce et al., 1984). g eologia c roatica jingya et al.: geochronology, geochemistry, and tectonic significance of the shirenshan gneiss in the southern margin of the north china block 45 block. gneiss may be formed due to partial melting of the taihua group and deformation of the luoluan fault zone. (4) combining regional tectonic evolution characteristics and geochemical characteristics of the shirenshan gneiss, the authors believe that the shirenshan gneiss in the southern margin of the north china block has the structural properties of an intraplate granite. this suggests that during the late caledonian period, the southern margin of the north china block was in a back-arc extension environment caused by the rupture of the subducting slab. acknowledgement this study was supported by the national nature science foundation of china (nos. 41572177, 41272213, 41573023, 41072161, 41502193, 41272222). the authors wish to express their gratitude to the reviewers for their thoughtful suggestions and comments. thanks are also due to all who have contributed to the execution of this research. references bonin, b. (2004). do coeval mafic and felsic magmas in postcollisional to within-plate regimes necessarily imply two contrasting, mantle and crustal, sources? a review.– lithos, 78/1, 1–24. doi: 10.1016/j.lithos.2004.04.042 cawood, p. a., wang, y. j. & xu, y. j. (2013): locating south china in rodina and gondwana: a fragment of greater india lithosphere? – geology, 41/8, 903–906. doi: 10.1130/g34395.1 chappell, b. (1999): aluminium saturation in i and s-type granites and the characterization of fractionated haplogranites.– lithos, 46/3, 535–551. doi: 10.1016/s00244937(98)00086-3 collins, w.j. (1982): nature and origin of a type granites with particular reference to southeastern australian.– contributions to mineralogy and petrology, 80/6, 189–200. dong, y.p., zhang, g.w. & zhao, x. (2003): the proterozoic tectonic framework and evolution of the north qinling orogen, central china. (in chinese, with an english abstract).– geotectonica et metallogenia, 27/2, 115–124. douce, a.e.p. & beard, j.s. (1995): dehydration-melting of biotite gneiss and quartz amphibolite from 3 to 15 kbar.– journal of petrology, 36/3, 707–738. doi: 10.1093/ petrology/36.3.707 eby, g.n. (1990): the a-type granitoids: a review of their occurrence and chemical characteristics and speculations on their petrogenesis.– lithos, 26/1–2, 115–134. doi: 10.1016/0024-4937(90)90043-z eby, g.n. (1992): chemical subdivision of the a-type granitoids: petrogenetic and tectonic implication.– geology, 20/7, 641–644. doi: 10.1130/0091-7613(1992)020< 0641:csotat>2.3.co;2 ferrar, l. (2004): slab detachment control on mafic volcanic pulse and mantle heterogeneity in central mexico.– geology, 32/1, 77. doi: 10.1130/g19887.1 frost, b.r., barnes, c.g., collins, w.j., arculus, r.j., ellis, d.j. & frost, c.d. (2001): a geochemical classification for granitic rocks.– journal of petrology, 42/11, 2033–2048. doi: 10.1093/petrology/42.11.2033 gao, x.y., zhao, t.p. & chen, w.t. (2014): petrogenesis of the early cretaceous funiushan granites on the southern margin of the north china craton: implications for the mesozoic geological evolution.– journal of asian earth sciences, 94/2014, 28–44. doi: 10.1016/j.jseaes.2014.07.042 jolivet, l., menant, a. & sternai, p. (2015): the geological signature of a slab tear below the aegean.– tectonophysics, 659, 166–182. doi: 10.1016/j.tecto.2015. 08.004 king, p.l., white, a.j.r. & chappell, b. w. (1997): characterization and origin of aluminous a-type granites from the lachlan fold belt, southeastern australia.– journal of petrology, 38/3, 371–391. doi: 10.1093/petroj/38.3.371 liu, y.s., gao, s., yuan, h.l., zhou, l., liu, x.m., wang, x.c., hi, z.c. & wang, l.s. (2004): u/pb zircon ages and nd, sr and pb isotopes of lower crustal xenoliths from north china craton: insights on evolution of lower continental crust.– chemical geology, 211/1–2, 87–109. doi: 10.1016/j.chemgeo.2004.06.023 liu, y.s., hu, z.c., zong, k.q., cao, c.g., cao, s., xu, j. & chen, h.h. (2010): reappraisement and refinement of zircon u-pb isotope and trace element analyses by la-icp-ms. (in chinese, with an english abstract).– chinese science bulletin, 55/15, 1535–1546. lu, s.w. (1995): geological characteristics of granite in funiushan region and its genesis. (in chinese, with an english abstract).– henan geology, 13/3, 183–190. maniar, p.d. & piccololi, p.m. (1989): tectonic discrimination of granitoids.– geological society of america bulletin, 101/5, 635–643. doi: 10.1130/0016-7606(1989) 101%3c0635:tdog%3e2.3.co;2 mingram, b., trumbull, r. b. & littman, s. (2000): a petrogenetic study of anorogenic felsic magmatism in the cretaceous paresis ring complex, namibia: evidence for mixing of crust and mantle-derived components.– lithos, 54/1, 1–22. doi: 10.1016/s0024-4937(00)00033-5 pearce, j.a., harris, n.b.w. & tindle, a.g. (1984): trace element distrimination diagrams for the tectonic interpretation of granitic rocks.– journal of petrology, 25/4, 956–983. peccerillo, a. & taylor, s.r. (1976): geochemistry of eocene calc-alkaline rocks from kastamonu area – northern turkey.– contributions to mineralogy and petrology, 58, 63–81. pei, x.z., zhang, w.j. & wang, t. (1995): geological features and tectonic evolution of the north qinling mountains orogenic belt. (in chinese, with an english abstract).– northwestern geology, 16/4, 8–12. pitcher, w.s. (1982): granite type and tectonic environment.– mountain building processes.– academic press, london, 19–40. qorbani, e., bianchi, i. & bokelmann, g. (2015): slab detachment under the eastern alps seen by seismic anisotropy.– earth and planetary science letters, 409, 96–108. doi: 10.1016/j.epsl.2014.10.049 ren, s.l. (2013): metamorphic deformation analysis of the funiushan tectonic belt, qinling.– hefei university of technology press. ren, s.l, liu, g.t. & song, c.z. (2016): deformation and metamorphic characteristics of amphiboles in the luonan-luanchuan fault belt of the qinling orogen and its significance. (in chinese, with an english abstract).– acta petrologica sinica, 32/3, 775–786. roberts, m.p. & clemens, j.d. (1993): origin of high-potassium, talc-alkaline, itype granitoids.– geology, 21, 825–828. doi: 10.1130/0091-7613(1993)021%3c08 25:oohpta%3e2.3.co;2 rudnick, r.l. & gao, s. (2003): composition of the continental crust. in: rudnick r. l. ed., treatise on geochemistry 3.– elsevier, amsterdam, 1–46. doi: 10.1016/b008-043751-6/03016-4 sisson, t., ratajeski, k., hankins, w. & glazner, a. (2005): voluminous granitic magmas from common basaltic sources.– contrib. miner. petrol., 148, 635–661. doi: 10.1007/s00410-004-0632-9 song, c.z., liu, g.s. & niu, m.l. (2002): genozoic structures and dynamics on the northern margin of the qinling-dabie orogenic belt. (in chinese, with an english abstract).– geological bulletin of china, 21/9, 530–535. song, c.z., zhang, g.w. & niu, m.l. (2006): oblique collision and convergence factor on the northern margin of the qinling orogenic belt. (in chinese, with an english abstract).– geology in china, 33/1, 48–55. sun, s.s. & mcdonough, w.f. (1989). chemical isotopic systematics of oceanic basalts: implications for mantle composition and processes.– magmatism in the ocean basins.– geological society of london special publication, 42/1, 313–345. doi: 10.1144/gsl.sp.1989.042.01.19 sylvester, p.j. (1998): post-collisional strongly peraluminous granites.– lithos, 45, 29–44. doi: 10.1016/s0024-4937(98)00024-3 turner, s., sandiford, m. & foden, j. (1992): some geodynamic and compositional constraints on “postorogenic” magmatism.– geology, 20/10, 931. wang, j.g. & lu, x.x. (1988): the petrological features of funiushan granite. (in chinese, with an english abstract).– geology of henan, 6/3, 35–40. wang, j.y., ren, s.l. & li, j.h. (2017): study on deformation of shirenshan block in the north qinling.– acta geologica sinica – english edition, 91/1, 351–352. wang, j.y., ren, s. l., jiang, d. z., dong, s. w., li, j. h., li, l. m., song, c. z., han, h. & li, z. q. (2019): new zircon u-pb ages of the shirenshan gneiss, north qinling and their geological implications.– acta geologica sinica – english edition, 93/1, 238–240. doi: 10.1111/1755-6724.13792 whalen, j.b., currie, k.l. & chappell, b.w. (1987): a-type granites: geochemical characteristics, discrimination and petrogenesis.– contributions to mineralogy and petrology, 95/4, 407–419. doi: 10.1007/bf00402202 wu, a.m., martarelli, l., ma, r., wang, h., yang, h.f. & bu, h. (2018): common and different features of chinese and italian hydrogeological mapping guidelines.– geologia croatica, 71/2, 105–111. doi: 10.4154/gc.2018.07 xu, z.q., li, y. & liang, f.h. (2015): a connection between of the paleo-tethys suture zone in the the taihua group on the southern margin of the north china craton: further insights from u–pb ages and hf isotope compositions of zircons.– mineral. petrol., 97, 43–59. xu, z.q., li, y.l. & tang, y.q. (1990): the formation of the qinling mountain china as the backbone of china, convergence, collision and intracontinental subduction – in chinese, with an english abstract.– bulletin of the chinese academy of geological sciences, 20/1, 130–132. zhang, g.w., dong, y.p. & yao, a.p. (1997): the crustal compositions,structures and tectonic evolution of the qinling orogenic belt – in chinese, with an english abstract.– geology of shanxi, 15/2, 1–14. zhang, z.w. & li, s.m. (1998): sm–nd and rb–sr ages of the archean taihua group metamorphic rocks in the xiong’ershan region, western henan province.– in: cheng, y.q. (ed.: precambrian geological research papers of the north china platform. geological publishing house, beijing, 123–132. zhang, g.w., zhang, b.r., yuan, x.c. & xiao, q.h. (2001). qinling orogenic belt and continental dynamics (in chinese, with an english abstract).– sci. press, beijing, 1–806. 2021 | 74/2 | 153–162 | 7 figs. | 5 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction during the last decade, numerous studies addressed the accumulation, distribution, association, and mobilization of trace metals in recent sediments and soils (morelli et al., 2012; kalantzi et al., 2013; jurina et al., 2015; kalnejais et al., 2015; brunović et al., 2019). recently, sondi et al. (2017) studied the distribution of trace metals as pollution and palaeo-redox proxies and indicators of authigenic mineral formation in a modern shallow anoxic carbonate of the mljet lakes. in the same sedimentation system, bura-nakić et al. (2020) studied the geochemical cycling of mo and u isotopes used as proxies to determine the physicochemical conditions in the water column during sedimentation and trace metal accumulation processes in sedi ments in the recent past. cuculić et al. (2018) determined metal concentrations in associated sediments and the surrounding bedrocks and soils around marine lakes at the mljet island. the authors discovered that anthropogenic influences and natural processes of soil leaching and dry/wet precipitation were responsible for the elevated trace metals. razum et al. (2020) investigated element concentrations in a sediment core from the veliko jezero lake to obtain information about environmental conditions and recent sedimentation processes. the relationship between the geochemical and mineralogical characteristics of calcocambisol, colluvium and recent marine lake sediment of the narrow seashore intertidal zone: a case study from the veliko jezero (mljet island, croatia) stanko ružičić1,*, goran durn1, ivan sondi1, lucija mihaljević1 and maja ivanić2 1 university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, hr-10000 zagreb, croatia; (*corresponding author: stanko.ruzicic@rgn.unizg.hr) 2 ruđer bošković institute, division for marine and environmental research, bijenička cesta 54, hr-10000 zagreb, croatia doi: 10.4154/gc.2021.10 abstract this study investigates the mineral composition, particle size distribution and geochemical characteristics of calcocambisol, colluvium and recent marine lake sediment in a narrow intertidal seashore zone of the veliko jezero on the island of mljet (croatia). the obtained results show that the fractions of calcocambisol/colluvium less than 2 mm and 2 µm display similar particle size distribution (psd) curves compared to marine lake sediments containing larger particles in these fractions. the smallest fractions of the investigated materials that are less than 1 µm show identical psd curves. the bulk and clay mineral composition of the marine lake sediment show that the non-carbonate fraction is derived from weathering of the surrounding soils and colluvium containing quartz, feldspars and phyllosilicates (illitic material, kaolinites, chlorite, and a mixedlayer clay mineral, mlcm), as well as the authigenic formation of early-diagenetic pyrite, while one part is related to the yield of material by aeolian deposition (amphibole). the observed difference between the phyllosilicate mineral phases in the clay fraction of the calcocambisol/colluvium and the carbonate-free clay fraction of the marine lake sediment is related to 1) the presence of chlorite in the marine lake sediment and 2) the higher content of mlcm in the calcocambisol/colluvium. the chlorite in the marine lake sediment was inherited from the calcocambisol/colluvium as a result of soil erosion prior to its complete destabilization in the soil. high chemical index of alteration (cia) values in the calcocambisol and colluvium clearly indicate their intense weathering. based on the sm/nd and ti/al ratios, it can be concluded that the aluminosilicates in the calcocambisol, colluvium and marine lake sediment are of the same provenance. the distribution of each analysed element among the sequential fractions is very similar in both the calcocambisol and colluvium. the highest concentrations for most of trace elements in the calcocambisol, colluvium and marine lake sediment was determined in their residual fraction. mn, co and pb show a different partitioning between the calcocambisol/colluvium and marine lake sediment, respectively. however, systematic studies of the influence of soils on the formation and geochemical characteristics of recent sediments from the seashore intertidal zone of the adriatic sea have, to our knowledge, rarely been reported in the literature (sondi et al., 1994; jurina et al., 2015). rogan šmuc et al. (2018) studied the distribution of heavy metals in surface sediments from koper bay (north adriatic sea) using a sequential extraction procedure. the authors found that the majority of the analyzed metals could be considered immobile due to their high affinity for binding to the residual phase. it is well-known that the presence and distribution of the mineral phase gives an indication of the origin of the material of which the sediments are composed. numerous studies of mineral distributions in recent marine sediments dealing with this issue have been implemented (tomadin, 2000; govorčin et al., 2001; sondi & juračić, 2010). most recently, ivanić et al. (2020) analyzed the mineral composition of recent marine sediments and concluded that the dominant input of terrigenous material into the mljet marine lake system is limited to soil erosion and aeolian deposition. previous studies (sondi & juračić, 2010) of the mljet lakes have shown that the authigenic formaarticle history: manuscript received december 09, 2020 revised manuscript accepted march 22, 2021 available online june 30, 2021 keywords: calcocambisol, colluvium, marine lake sediment, mineralogy, geochemical characterization g eo lo gi a c ro at ic a geologia croatica 74/2154 tion of aragonite is the main source of sedimentary material in the deeper parts of the mljet lakes, while mg-calcite is the product of biomineralization. calcite and a small amount of dolomite are derived from the surrounding carbonate rocks. until now, no studies have been conducted in the mljet lakes that would indicate the role of weathering of calcocambisols and colluvium and their contribution to the formation of recent sediments and the distribution of trace elements in the intertidal seashore zone of the mljet marine lakes. this study aims to investigate the influence of local soil (calcocambisol) and colluvium (consisting of soil and rock fragments accumulated on the lower parts of the slopes along the lakeshore) as a potential detrital source material for marine lake sediments of the intertidal zone of the veliko jezero. in addition, the influence of soil wear on the geochemical distribution of trace elements in this zone was also investigated. accordingly, this study is based on detailed mineralogical and geochemical analyses (sequential extraction analysis and selected geochemical indicators). 2. study area the veliko jezero (the part of the mljet lakes system) is located on the western part of the island of mljet (adriatic sea) (fig. 1a). the geological features of this area were described in detail by korolija et al. (1977) and gušić et al. (1995). according to korolija et al. (1977), mljet island is divided into two geological units: mesozoic carbonate deposits, which form most of the island, and quaternary deposits, which are sporadically present on the mesozoic carbonates. the mesozoic carbonates are divided into the upper jurassic limestones, jurassic-cretaceous dolomites, lower cretaceous limestones, and cretaceous limefigure 1. geographical map of the western part of mljet island with the sampling locations (a) and with corresponding pedological map (b) (modified after martinović, 1982). g eologia c roatica ružičić et al.: the relationship between the geochemical and mineralogical characteristics of calcocambisol, colluvium and recent marine ... 155 stones and dolomites. the lower cretaceous limestone is characterized by laminated and fenestrae mudstone. this setting is characterized by several karst depressions (sinkholes or dolines) formed under subaerial exposure. some of these depressions are submerged today due to holocene sea-level rise (surić et al., 2005), one of which is the present-day veliko jezero. since the semi-enclosed water bodies of veliko jezero are loosely connected to the open sea, they contain seawater and can therefore be called marine lakes (bakran-petricioli & petricioli, 2008; sondi & juračić, 2010). the main soil types on mljet island are calcocambisol, rendzina, and calcomelanosol (martinović, 1982) (fig. 1b). according to martinović (1982), the most common soil type in the study area is calcocambisol. this soil was developed on lower cretaceous limestone and jurassic dolomite (gušić et al., 1995). 3. materials and methods 3.1. fieldwork and sampling the calcocambisol, colluvium, and recent marine lake sediment were collected during field investigations in june 2015. the first sample was a subsurface soil taken from a depth of up to 20 cm and represents the b horizon (vj-1a). it was determined as a calcocambisol (fig. 2a, and b). sample (vj-1b) (fig. 2a and c), was sampled in a flat area of the veliko jezero coastal zone and determined as colluvium. colluvium is situated in contact with the veliko jezero and besides the erosion and accumulation of materials and formation of the colluvial soil, there is occasional flooding during tides from the lake. the third sample (vj-1c) was collected from surface marine lake sediment (at a depth of approx. 2 m) originating from the veliko jezero (fig. 2a). 3.2. laboratory methods a portion of each sample was crushed and sieved through a 2 mm sieve for physical, chemical, and mineralogical analyses. the < 2 μm and < 1 μm fractions of the soil samples were separated by sedimentation in a cylinder and quantitatively obtained after the appropriate settling time. the ph, both in h2o and kcl (c = 1m), was measured in the 1:5 suspension (iso 10390, 2005). electrical conductivity of the samples was measured in water with a soil to water ratio of 1:5 using a cond 3110 wtw ec meter (iso 11265, 1994). particle-size distribution (psd) measurements were performed using laser diffraction (ls 13320, beckman coulter inc., usa). prior to measurements, the samples were dispersed in deionized water, left to soak overnight, and sonicated for 5 min before analysis. the particle size was calculated with proprietary software using the mie theory of light scattering (optical parameters: refractive index, 1.53; absorption index, 0.1). the mineral composition of the < 2 mm, < 2 μm, and < 1 μm fractions of the analyzed samples was determined by x-ray powder diffraction (xrd) using a philips diffractometer (graphite monochromator, cukα radiation, proportional counter). identification of clay minerals was based on the methods outlined by brown (1961), brindley & brown (1980), and moore & reynolds (1989). semi-quantitative mineral composition of all fractions was determined by comparison with standards of mixed minerals (quartz, plagioclase, halite, and carbonates). the carbonate content was determined by the volumetric method (iso 10693, 1995). iron and manganese extractable with na dithionite-citrate bicarbonate (fed, mnd) were obtained using the method of mehra & jackson (1960), while proportions extractable with ammonium oxalate (feo, mno) were acquired according to schwertmann (1964). the organic matter (om) from the samples was removed using sodium hypochlorite (naocl) according to the slightly modified treatment proposed by kaiser & guggenberger (2003). the total organic carbon (toc) content of the samples (after dilution of organic matter and carbonates) was determined by combustion of acid-insoluble matter in a leco ir–212 carbon analyser (usa), after treatment with hot 1:1 diluted 18% hcl. figure 2. a) larger area of seashore intertidal sampling locations displayed in figure 1 (source: https://geoportal.dgu.hr/); b) calcocambisol soil; c) colluvium. g eo lo gi a c ro at ic a geologia croatica 74/2156 different binding sites of trace metals in samples were analyzed by sequential extraction. a series of reagents were used to extract operationally-defined phases (selectivity depends on factors such as chemicals used, time and nature of contact, and the sample to volume ratio) in a defined sequence from 1 g of the sample. a sequential extraction scheme was used according to the european community bureau of reference bcr (ure et al., 1993), which gave four fractions: acid (bound to carbonates cc), reducible (bound to iron and manganese oxides, hydroxides and oxyhydroxides femn), oxidizable (bound to organic matter and/or sulphides or) and residual (total dissolving using aqua regia res). the sequential extraction was performed in centrifuge tubes (polyethylene, 50 ml). between each successive extraction step, the liquid phase was separated by centrifugation at 3000 rpm for 10 minutes. all reagents used in the extraction procedures were of analytical grade. the resulting solutions were analyzed by flame atomic absorption spectrometry (aanalyst 700, perkin elmer). the chemical composition of the samples was determined using the commercial acme analytical laboratory. major oxides were determined using an x-ray fluorescence spectrometer (xrf) following libo2 fusion. in order to characterize the calcocambisol/colluvium/marine lake sediment geochemically, the cia, and the molecular ratio of selected elements (ti/al, al/si, ba/sr, sm/nd, σ base (ca, mg, na, k)/al, σ base (ca, mg, na, k)/ti) were used according to sheldon & tabor (2009). 4. results and discussion 4.1. physico-chemical properties of the analyzed samples all the analyzed samples showed a moderately alkaline reaction (phh2o), while phkcl steadily increased from calcocambisol (7.09) to marine lake sediment (8.17) (table 1). similar values of phh2o and phkcl were expected in marine lake sediment because it contains pore water with a high nacl content, which affects the phh2o measurement (both nacl and kcl are neutral salts). marine lake sediment was enriched in carbonates (table 1). compared to the calcocambisol (0.6 wt.%), the colluvium showed a slightly higher proportion of carbonates (0.8 wt.%). the highest organic matter (om) content (0.6 wt.%) was observed in the marine lake sediment and the lowest value (0.1 wt.%) was found in the colluvium sample (table 1). electrical conductivity (ec) increased rapidly from calcocambisol to marine lake sediment (table 1). the colluvium sample was collected on location in contact with the veliko jezero (fig. 2c), and occasional flooding during high tides from the marine lake occurs at this site. accordingly, marine salt water is the major carrier of ions responsible for the higher ec values in the colluvium sample. the highest ec value was determined in the marine lake sediment (table 1). this is also an effect of salt water which is confirmed by the determination of halite in marine lake sediment (table 3). apart from salt water, the highest value of ec can be explained with the leaching and weathering process of σbase/al (table 5) from calcocambisol and its accumulation in marine lake sediment. the fed/fet ratio (which is taken as an index of weathering, e.g. bech et al., 1997) in calcocambisol and colluvium is 0.6 and 0.54, respectively, and reflects a moderate degree of weathering of fe-containing primary silicates (table 1). low values of feo and the feo/fed ratio in calcocambisol and colluvium (tab le 1) indicate the low content of poorly crystalline fe oxides in these samples. in contrast, the marine lake sediment was relatively enriched in poorly crystallized fe oxides (feo/fed is 0.4) compared to the calcocambisol and colluvium samples. reverse trends were observed for poorly and well-crystallized mn phases (tab le 1). both the light brownish-grey colour of the marine lake sediment (table 2) and the low fed/fet ratio (table 1) clearly indicate that table 2. physical characteristics of analyzed samples. color (munsell soil color chart, 1994) material sand 2-0.063 mm (%) silt 0.063-0.002 mm (%) clay <0.002 mm (%) texture (soil science division staff, 2017) 2.5 yr 4/4 reddish brown calcocambisol 6.68 61.50 31.82 clayey silt 10 yr 4/4 brown colluvium 6.72 58.54 34.74 clayey silt 2.5 y 6/2 lightly brownish grey marine lake sediment 47.85 42.68 9.47 silty sand table 1. soil/colluvium and sediment physical and chemical characteristics. legend: ecelectrical conductivity (µs/cm), omorganic matter (wt. %), caco3carbonate content (wt. %), fediron extractable with na dithionite-citrate bicarbonate (wt. %), mnd-manganese extractable with na dithionite-citrate bicarbonate (mg/kg), feoiron extractable with ammonium oxalate (wt. %), mnomanganese extractable with ammonium oxalate (mg/kg), fettotal content of iron (wt. %). material phh2o phkcl ec caco3 om fet fed feo mnd mno feo/fed mno/mnd fed/fet calcocambisol 8.20 7.09 256 0.564 0.1 5.48 3.29 0.14 529 440 0.04 0.83 0.6 colluvium 8.07 7.67 7513 0.846 0.07 5.34 2.87 0.19 713 697 0.07 0.98 0.54 marine lake sediment 8.21 8.17 9550 72.44 0.64 1.01 0.29 0.12 23 9 0.4 0.37 0.29 table 3. semi-quantitative mineral composition of the < 2 mm fraction (based on the analysis of < 2 mm, < 2 μm and < 1 μm fractions). hl: halite. cal: calcite. cal 2: mg calcite. arg: aragonite. dol: dolomite. qtz: quartz. pl: plagioclase. kfs: potassium feldspar. amp: amphibole. gt: goethite. hem: hematite. py: pyrite. m: micaceous minerals (mica and illitic material). kln: kaolinite. chl: chlorite. 14å: smectite and/or vermiculite. mlcm: mixed-layer clay minerals in which type of interstratification and constituting clay minerals were not recognized with certainty. am: amorphous matter. material hl (%) cal (%) cal 2 (%) arg (%) dol (%) qtz (%) pl (%) kfs amp gt hem py m kln chl 14 å mlcm am calcocambisol ? 13 2 x x x x xxx xx ? xx x colluvium 1 1 14 3 x x x xxx xx ? xxx x marine lake sediment 2 35 7 39 8 x x x x ? ? x x x x ? x x “x” relative abundance of minerals based on x-ray diffraction (no quantitative value is assigned to x). “?” mineral phase was not detected with certainty. g eologia c roatica ružičić et al.: the relationship between the geochemical and mineralogical characteristics of calcocambisol, colluvium and recent marine ... 157 this sediment is depleted in fe oxides and hydroxides compared to the calcocambisol and colluvium samples. the colour of the samples varied from reddish-brown (calcocambisol) to brown (colluvium) to a light brownish grey (marine lake sediment) (table 2). according to soil science division staff (2017) calcocambisol and colluvium are clayey silt, while marine lake sediment is silty sand (table 2). the particle size distribution (psd) curves for the native soil and sediment samples and their fractions of less than 2 and 1 μm are shown in figure 3. the native calcocambisol and colluvium show identical psd curves, indicating the presence of the clay and clayey silt fractions with an average particle size of 18 μm (fig. 3a). in contrast, the marine lake sediment contains larger particles (sand and clayey silt fraction) with an average particle size of 131 μm. the fraction of soils ˂ 2 µm shows comparable psd curves (average sizes 0.5 and 0.4 μm), while the pds curve for the marine lake sediment shows the presence of larger particles (average size 1.2 μm) (fig. 3b). the smallest fraction (< 1 µm) of all samples has similar psd curves, indicating the presence of a predominantly submicron-sized fraction (fig. 3c). 4.2. mineral composition of the analyzed samples both the bulk and clay mineral compositions of the calcocambisol and colluvium are very similar (tables 3 and 4; figs. 4 and 5). the main mineral phases in the calcocambisol and colluvium are phyllosilicates and quartz. plagioclase, k-feldspar, and fe-oxides (goethite and hematite) were determined as minor mineral phases. amphibole was detected as a minor phase only in the calcocambisol. colluvium contains calcite and dolomite as minor components. these mineral phases are derived from limestone and dolomite fragments incorporated in the colluvium situated on the lower parts of the slopes along the lakeshore. the main mineral phases in the clay fraction are illitic material, kaolinites, and a mixed-layer clay mineral (mlcm), in which the type of the interstratification and the constituent clay minerals were not recognized with certainty (table 4). quartz, hematite, and goethite are the minor mineral phases in this fraction. both samples also contain amorphous matter. aragonite and calcite are major constituents, mg-calcite, and dolomite subordinate while halite, quartz, plagioclase, k-feldspar, amphibole, pyrite, and phyllosilicates are minor mineral phases in the marine lake sediment (table 3, fig. 6). since this sample is rich in carbonates, it was necessary to analyze the carbonate-free residue to compare the non-carbonate components of the marine lake sediment with the calcocambisol and the collutable 4. mineral composition of the < 2 µm fraction of calcocambisol, colluvium and insoluble residue of the marine lake sediment, respectively. ill: illitic material. for other abbreviations see table 3. material qtz pl gt hem py ill kln chl 14å mlcm am calcocambisol x x x xxx xx ? xx xx colluvium x ? x x xxx xx ? xxx xx marine lake sediment x ? ? x xxx xx xx ? x x table 5. ratios of analyzed chemical indicators. material al/si ti/al σbase/al σbase/ti cia ba/sr sm/nd calcocambisol 0.24 0.06 0.49 3.20 77.51 3.36 0.1832 colluvium 0.24 0.06 0.65 4.29 72.13 a 1.97 0.1833 marine lake sediment 0.20 0.07 19.85 14.86 5.04 a 0.04 0.1750 cia=chemical index of alteration calculated as ala 100/(al + ca + k + na). a -sample contains calcite and dolomite. figure 3. particle-size distribution of (a) original samples (< 2 mm), (b) original samples (< 2 µm) and (c) original samples (< 1 µm). legend: calcocambisol (–), colluvium (-), marine lake sediment ( _ ). g eo lo gi a c ro at ic a geologia croatica 74/2158 vium samples (table 4). the main mineral phases in the carbonate-free clay fraction of the marine lake sediment are illitic material and kaolinites (both the poorlyand well-crystallized kaolinite were determined). these minerals were also determined as the main constituents in the clay fraction of calcocambisol and colluvium. compared to the calcocambisol and colluvium, the carbonate-free clay fraction of the marine lake sediment contained pyrite and chlorite. it is important to point out that mlcm, which occurs along with illite and kaolinite as the main mineral phase in the clay fraction of calcocambisol and colluvium, was also determined in the clay fraction of the marine lake sediment, but as a subordinate mineral phase. the bulk mineralogy of the studied marine lake sediment (table 3, fig. 6) agrees with the results previously obtained by sondi & juračić (2010) and sondi et al. (2017). they found that the authigenic formation of aragonite is the main source of sedimentary material in the mljet lakes, mg-calcite is the product of biomineralization, while calcite and dolomite originate from the surrounding carbonate rocks. the occurrence of aragonite is significant and is a consequence of its authigenic formation in the aquatic system during the whiting events (sondi & juračić, 2010). they also documented that the increased concentration of strontium in the recent sediment of the mljet lakes is an indicator of authigenic aragonite formation. according to sondi et al. (2017), the formation of aragonite in the mljet lakes has been a continuous process over several hundred years. we found pyrite in both < 2 mm and < 2 µm fractions. this mineral phase indicates occasional events of oxygen deficiency in the lake system. indeed, ivanić et al. (2020) determined micron-sized early-diagenetic framboidal pyrite in sediments from the malo jezero (fig. 1a). they also analyzed the mineral composition of the clay fraction of the sediment from malo jezero and discovered that illite and kaolinites were the main phyllosilicate phases, while mlcms were determined as a minor mineral component. they concluded that the input of terrigenous material into the lake system is limited to soil erosion and aeolian deposition. in addition to illite, kaolinites and mlcm in the marine lake sediment from veliko jezero we also detected chlorite (table 4). it is important to note that this mineral phase was not detected in either the calcocambisol or colluvium (table 4). dominant mineral phases in the < 2 µm fraction of calcocambisol and colluvium are comparable to the dominant mineral phases found in the clay fraction of calcocambisol samples from istria. durn et al. (2019) found that kaolinites (both the poorly and well-crystallized kaolinite) and illitic material are the dominant clay mineral phases in the calcocambisol sample from istria, while the main mineral phases in the clay fraction of calcocambisol and colluvium are illitic material, kaolinites and mlcm. we presume that mlcm probably formed as a result of chlorite destabilization during pedogenesis, a process already observed figure 5. x-ray diffractograms of clay fractions (< 2 µm and < 1 µm) (a-f) of the colluvium, a-untreated clay fraction (< 2 µm) with difraction line 060 [a], b-untreated clay fractions (< 1 µm) with difraction line 060 [b], ctreated clay fraction (< 2 µm) 24 hours with hcl (1:1), dclay fraction (< 2 µm) glycerol solvated, eclay fraction (< 2 µm) ethylene glycol solvated, fclay fraction (< 2 µm) heated for 2 hours at 650°c. figure 4. x-ray diffractograms of clay fractions (< 2 µm and < 1 µm) (a-f) of the calcocambisol, a-untreated clay fraction (< 2 µm) with difraction line 060 [a], buntreated clay fractions (< 1 µm) with difraction line 060 [b], ctreated clay fraction (< 2 µm) 24 hours with hcl (1:1), dclay fraction (< 2 µm) glycerol solvated, eclay fraction (< 2 µm) ethylene glycol solvated, fclay fraction (< 2 µm) heated for 2 hours at 650°c. g eologia c roatica ružičić et al.: the relationship between the geochemical and mineralogical characteristics of calcocambisol, colluvium and recent marine ... 159 figure 6. x-ray diffractograms of bulk sample (a-b) and clay fractions (c) of the marine lake sediment from veliko jezero a-untreated, b-treated with ph 4.5 nahac/ ac pufer, c-untreated sample with clay fraction < 2 µm. for abbreviations see tables 3 and 4. figure 7. distribution of trace elements in the analyzed samples. a) cu; b) fe; c) mn; d) zn; e) co; f) ni; g) cr; h) pb. units are in mg/kg. legend: ccbound to carbonates, femnbound to iron and manganese oxides, hydroxides and oxyhydroxides, orbound to organic matter and/or sulphides and resresidual (total dissolving using aquaregia). g eo lo gi a c ro at ic a geologia croatica 74/2160 in the formation of mixed-layer chlorite vermiculite in pseudogley on loess in the pannonian region of croatia (rubinić et al., 2015) and in polygenetic soil on late glacial loess at susak island (durn et al., 2018). the presence of amphibole in calcocambisol indicates that its parent material can mostly be derived from aeolian sands deposited on the se part of mljet island rather than from the insoluble residue of limestone and dolomite. namely, pavelić et al. (2014) found amphiboles in aeolian deposits on the central adriatic islands. they determined that the amphiboles were formed by the weathering processes of various metamorphic and magmatic rocks originating from the inner dinarides, which were transported to the coastal belt by the palaeo-neretva river during glacial sea-level subsidence when the central adriatic islands were part of the mainland. during the interglacials and interstadials in the pleistocene, the aeolian deposits found on the coast and on the islands along the adriatic sea were exposed to soil-forming processes. therefore, thin aeolian sediments situated on limestones and dolomites might have contributed to the soil parent material. based on the mineral composition, we can conclude that the noncarbonate fraction of the marine lake sediment originates from weathering and erosion of the surrounding soils and colluvium (quartz, feldspars, and phyllosilicates), authigenesis (appearance of early-diagenetic pyrite) and probably direct aeolian deposition of mineral components into the marine lake (amphibole could be derived from local soils and/or direct aeolian input). the observed difference between the phyllosilicate mineral phases in the clay fraction of calcocambisol/colluvium and the carbonate free clay fraction of the marine lake sediment is related to 1) the presence of chlorite in the marine lake sediment and 2) the higher content of mlcm in the calcocambisol/colluvium. we tentatively propose that the chlorite in the marine lake sediment was inherited from calcocambisol/colluvium as a result of soil erosion prior to complete chlorite destabilization in the soil. the higher share of mlcm in calcocambisol/colluvium compared to marine lake sediment supports this proposal. the absence of chlorite in the sediment from malo jezero (ivanić et al., 2020) is probably the result of local soil distribution/erosion and the fact that the marine lake sediment in this study was sampled closer to the lake shore, whereas in the case of malo jezero the sediment was sampled in the deeper part of the lake. 4.3. sequential chemical extraction results in this study, sequential extraction analyses were applied to determine the diverse distribution of trace elements in sequenced fractions of the investigated calcocambisol/colluvium and marine lake sediment (fig. 7). trace elements in soils are partitioned between the different phases present, i.e. organic matter, oxyhydroxides of iron and manganese, sulphides, clay minerals, and are retained on these solid phases by different mechanisms, i.e. ion exchange, complexation, precipitation or co-precipitation (benedetti et al., 1995; nemati et al., 2011), or are retained in the lattice of soil minerals. the partitioning of all analyzed elements among the fractions (cc, femn, or, res) is very similar for calcocambisol and colluvium (fig. 7). different partitioning compared to the marine lake sediment was observed for mn, pb and co (figs. 7c and e). the content of cu, mn, zn, co, ni, and cr is significantly lower in the marine lake sediment compared to calcocambisol and colluvium, as this sample contains more than 70% carbonate mineral phases and consequently a lower share of clay minerals and fe and mn oxyhydroxides (table 1). the relatively low concentrations of mn, co, ni, pb and cr (fig. 7) in all the analyzed samples were measured in the cc fraction. the distribution of trace elements in the calcocambisol/colluvium showed the highest concentrations of cu, fe, zn, ni, cr and pb in the res fraction, while the highest concentrations of mn and co were present in the femn fraction (figs. 7c, e). the manganese content in the femn fraction of calcocambisol and colluvium also agrees well with the data for poorly and well-crystallized mn phases (table 1), clearly indicating that mn is predominantly associated with mn oxides. cobalt is also classically associated with mn oxides, which is confirmed by other studies (latrille et al., 2001; palumbo et al., 2001; liu et al., 2002; bradl, 2004; cornu et al., 2005). according to vodyanitskii et al. (2009) in the formation of oxides in soils, mn acts as an individual phase carrying metals such as cu, co, cr, ni, pb and zn, which are associated with mn oxides by coprecipitation and substitution. in many studies (gasparatos et al., 2005; neaman et al., 2008), the distribution of co in femn fine-grained soil aggregates follows that of mn. this accumulation of co on soil particles is due to the oxidation of absorbed co(ii) to co(iii) on mn oxides and their incorporation into the mn oxide mineral structure. based on the distribution of trace elements in the marine lake sediment (fig. 7), it can be concluded that the highest concentrations of all the analyzed elements (except pb) were determined in the res fraction. the highest concentrations of pb were present in the femn fraction (fig. 7h). this can probably be explained by the formation of stable complexes between pb and fe oxyhydroxides. other studies (ip et al., 2007; rogan šmuc et al., 2018) also confirmed a high bounding affinity of pb to the reducible phase in marine sediments. after the residual fraction, the femn fraction is the most fe-rich fraction in calcocambisol and colluvium (fig. 7b). in contrast, in marine lake sediment, after the residual fraction, the or fraction is enriched in fe (fig. 7b). besides fe, this fraction in the marine lake sediment is also enriched in pb, cr, ni, zn and cu, which can probably be linked to sulphides (pyrite) and organic matter. 4.4. geochemical indicators of weathering for geochemical characterization of weathering, the molecular al/si ratio, and the chemical index of alteration (cia) were used. both indexes are considered to be measures for weathering and “clayness” (sheldon & tabor, 2009), while the ba/sr, the ʃbase (ca, mg, na, k)/al and the ʃbase (ca, mg, na, k)/ti ratios represent the leaching behaviour during weathering processes (sheldon, 2006). it was also established that the ti/al and sm/nd ratios can be used as provenance indicators (sheldon, 2006). the al/si ratio in both calcocambisol and colluvium is the same (table 5), which equally indicates processes of hydrolysis and the distribution of clay minerals. perez-huerta & sheldon (2006) used ʃbase/al for the exchangeable terrigenous input of nutrients in shallow marine systems derived from soils. according to the ʃbase/al and ʃbase/ ti ratios (table 5), the colluvium is slightly enriched in basic cations, probably related to the presence of calcite and dolomite, which are accessory mineral phases in this sample (table 3). lower cia and ba/sr values in the colluvium are consistent with this statement (tables 3 and 5). both the ʃbase/al and ʃbase/ti ratios, show that the marine lake sediment is highly enriched in basic cations, which is a consequence of the presence of carbona te g eologia c roatica ružičić et al.: the relationship between the geochemical and mineralogical characteristics of calcocambisol, colluvium and recent marine ... 161 minerals, particularly aragonite, calcite and mg-calcite, which are the dominant mineral components in this sample (table 3). very high cia values in the calcocambisol and colluvium clearly indicate intense weathering (table 5). according to sheldon & tabor (2009), the cia is a measure of the weathering of feldspar minerals and their hydration during the formation of clay minerals. accordingly, as the clay content increases, the al concentration also increases, whereas the ca, k, and na content should decrease, resulting in higher cia values. the cia values obtained in this study are in general agreement with the mineral composition and particle size distribution of the analysed calcocambisol and colluvium. the predominance of kaolinite and illite, the share of the clay fractions (table 2) and a lower proportion of k-feldspar and plagioclase (tables 3 and 4), confirmed the high cia values in the calcocambisol/colluvium (table 5). the sm/nd ratio indicates potential source materials, acidification, leaching, and weathering intensity and can be used in relatively stable pedogenic environments (sheldon & tabor, 2009). the sm/nd ratio was slightly lower in the marine lake sediment compared to the calcocambisol/colluvium samples (table 5). the ti/al ratio is particularly useful as a provenance indicator because ti contents may be quite variable among the different types of rocks (sheldon & tabor, 2009). in addition, durn et al. (2018) found that the ti/al ratio is also a good indicator of provenance for polygenetic soils formed on loess. the obtained results of the ti/al ratio for all the analyzed samples are almost the same (table 5) with a slight increase for the marine lake sediment. this is in accordance with the mineral composition of the insoluble residue of the samples (table 4), which is very similar except for pyrite and chlorite. therefore, based on both the sm/nd and ti/al ratios, we can conclude that the aluminosilicate part of the calcocambisol, colluvium and marine lake sediment is of the same provenance. based on the mineralogical and geochemical results, we concluded that the detrital parent material for the marine lake sediments of the veliko jezero are calcocambisol and colluvium. according to sondi et al. (2017), the detrital component of the first 50 cm of the sediment originates from the surrounding soil of the veliko jezero lake. apart from weathering and erosion of the surrounding soils, direct aeolian deposition of detrital material into the marine lake cannot be neglected. the results of the mineralogical analyses of the marine lake sediment of veliko jezero showed the presence of amphibole, which may indicate an aeolian source of the material. indeed, razum et al. (2020) found that the recent detrital part of the medium to coarse silt and sand fraction material in veliko jezero comes from aeolian sands, which are rich in minerals derived from mafic and ultramafic magmatic rocks. these observations are also in agreement with the origin of quaternary aeolian sands deposited on the southern sides of the mljet island and surrounding islands (babić et al., 2013; pavelić et al., 2014; kovačić et al., 2018). 5. conclusions the results of this study provide insight into the particle size distribution (psd), mineral composition, and geochemical characteristics of the calcocambisol, colluvium, and recent marine lake sediment of the narrow intertidal seashore zone of the veliko jezero lake on mljet island. the fractions of calcocambisol/colluvium < 2 mm and < 2 µm show similar psd curves compared to the marine lake sediment, which contains larger particles in these fractions. however, the smallest fraction (< 1 µm) of all analyzed materials have similar psd curves implying the presence of a predominantly submicron-sized fraction with an average particle size less than 1 μm. very high cia values in calcocambisol and colluvium clearly indicate their intense weathering. based on both the sm/nd and ti/al ratios, we can conclude that the aluminosilicate part of the calcocambisol, colluvium and marine lake sediment is of the same provenance. both bulk and clay mineral compositions of the recent marine lake sediment revealed that the noncarbonate fraction originated from weathering of the surrounding soils and colluvium (e.g. illitic material, kaolinites, chlorite and mixed-layer clay minerals), authigenesis (early-diagenetic pyrite) and possibly direct aeolian deposition of mineral components to the marine lake ( amphibole). the distribution of each analysed element among the sequential fractions is very similar in both the calcocambisol and colluvium. different partitioning in the calcocambisol/colluvium compared to the marine lake sediment was observed for mn, co and pb. the femn fraction is a major sink for mn and co in the calcocambisol/colluvium and for pb in the marine lake sediment respectively. acknowledgement this work has been fully supported by the croatian science foundation under the project nanomin (grant no. 2504). we thank prof. m. mileusnić for her help during fieldwork and n. tadej for suggestions during mineralogical analysis. references babić, lj., zupanič, j., vidović, j., razum, i., lužar-oberiter, b. & crnjaković, m. (2013): preservation of hanging aeolian deposits in insular karst depressions: sediment sources and implications for the pleistocene palaeogeography of the se adriatic archipelago.– aeolian research, 11, 171–189. doi: 10.1016/j.aeolia.2013.06.003 bakran-petricioli, t. & petricioli, d. (2008): habitats in submerged karst of eastern adriatic coast – croatian natural heritage.– croatian medical journal, 49, 455–458. doi: 10.3325/cmj2008.4.455 bech, j., rustullet, j., garigo, j., tobias, f.j. & martinez, r. (1997): the iron content of some red mediterranean soils from northeast spain and its pedoge nic significance.– catena, 28/3-4, 211–229. doi: 10.1016/s0341-8162(96)00039-2 benedetti, m.f., milne, c.j., kinniburgh, d.g., van riemsdijk, w.h. & koopal, l.k. (1995): metal ion binding to humic substances: application of the non-ideal competitive adsorption model.– environmental science & technology, 29, 446–457. doi: 10.1021/es00002a022 bradl, h.b. (2004): adsorption of heavy metal ions on soils and soils constituents.– journal of colloid and interface science, 277/1, 1–18. doi: 10.1016/j.jcis.2004.04.005. brindley, g.w. & brown, g. (1980): crystal structures of clay minerals and their x-ray identification.– mineralogical society, london, 495 p. doi: 10.1180/mono-5 brown, g. (1961): the x-ray identification and crystal structures of clay minerals.–mineralogical society, london, 544 p. brunović, d., miko, s., ilijanić, n., peh, z., hasan, o., kolar, t., šparica miko, m. & razum, i. (2019): holocene foraminiferal and geochemical records in the coastal karst dolines of cres island, croatia.– geologica croatica, 72/1, 19–42. doi: 10.4154/gc.2019.02 bura-nakić, e., sondi, i., mikac, n. & andersen, m.b. (2020): investigating the molybdenum and uranium redox proxies in a modern shallow anoxic carbonate rich marine sediment setting of the malo jezero (mljet lakes, adriatic sea).– chemical geology, 533, 119441. doi: 10.1016/j.chemgeo.2019.119441 cornu, s., deschatrettes, v., salvador-blanes, s., clozel, b., hardy, m., branchut, s. & le forestier, l. (2005): trace element accumulation in mn—fe—oxide nodules of a planosolic horizon.– geoderma, 125/1–5, 11–24. doi: 10.1016/j.geoderma.2004.06.009 cuculić, v., cukrov, n., kwokal, ž., strmečki, s. & plavšić, m. (2018): assessing trace metal contamination and organic matter in the brackish lakes as the major source of potable water.– environmental geochemistry and health, 40, 489–503. doi: 10.1007/s10653-017-9935-4 durn, g., rubinić, v., wacha, l., patekar, m., frechend, m., tsukamoto, s., tadej, n. & husnjak, s. (2018): polygenetic soil formation on late glacial loess on the susak island reflects paleo-environmental changes in the northern adriatic area.– quaternary international, 494, 236–247. doi: 10.1016/j.quaint.2017.06.072 durn, g., škapin, s.d., vdović, n., rennert, t., ottner, f., ružičić, s., cukrov, n. & sondi, i. (2019): impact of iron oxides and soil organic matter on the surface physicochemical properties and aggregation of terra rossa and calcog eo lo gi a c ro at ic a geologia croatica 74/2162 cambisol subsoil horizons from istria (croatia).– catena, 183, 104184, doi:10.1016/j. catena.2019.104184 gasparatos, d., tarenidis, d., haidouti, c. & oikonomou, g. (2005): microscopic structure of soil fe-mn nodules: environmental implications.– environmental chemistry letters, 2, 175–178. doi: 10.1007/s10311-004-0092-5 govorčin, d.p., juračić, m., horvatinčić, n. & onofri, v. (2001): holocene sedimentation in the soline channel (mljet lakes, adriatic sea).– natura croatica, 10/4, 247–258. gušić, i., velić, i. & sokač, b. (1995): geology of the mljet island.– in: durbeić, p. & benović, a. (eds.): proceedings of the symposium: island of mljet natural characteristics and social evaluation. croatian ecological society, zagreb, 35–53 ip, c.c.m., li, x.d., zhang, g., wai, o.w.h. & li, y.s. (2007): trace metal distribution in sediments of the pearl river estuary and the surrounding coastal area, south china.– environmental pollution, 147/2, 311–323. doi: 10.1016/j.envpol.2006.06.028 iso 10390 (2005): soil quality–determination of ph.– international organisation for standardisation, switzerland. iso 10693 (1995): soil quality–determination of carbonate content–volumetric method.– international organisation for standardisation, switzerland. iso 11265 (1994): soil quality – determination of the specific electrical conductivity.– international organisation for standardisation, switzerland. ivanić, m., durn, g., škapin, s.d. & sondi, i. (2020): size-related mineralogical and surface physicochemical properties of the mineral particles from the recent sediments of the eastern adriatic sea.– chemosphere, 249, 126531. doi: 10.1016/j. chemosphere.2020.126531 jurina, i., ivanić, m., vdović, n., troskot-čorbić, t., lojen, s., mikac, n. & sondi, i. (2015): deposition of trace metals in sediments of the deltaic plain and adjacent coastal area (the neretva river, adriatic sea).– journal of geochemical exploration, 157, 120–131. doi: 10.1016/j.gexplo.2015.06.005 kaiser, k. & guggenberger, g. (2003): mineral surfaces and soil organic matter.– european journal of soil science, 54/2, 219–236. doi: 10.1046/j.1365-2389.2003. 00544.x kalantzi, i., shimmield, t.m., pergantis, s.a., papageorgiou, n., black, k.d. & karakassis, i. (2013): heavy metals, trace elements and sediment geochemistry at four mediterranean fish farms.– science of the total environment, 444, 128–137. doi: 10.1016/j.scitotenv.2012.11.082 kalnejais, l.h., martin, w.r. & bothner, m.h. (2015): porewater dynamics of silver, lead and copper in coastal sediments and implications for benthic metal fluxes.– science of the total environment, 517, 178–194. doi: 10.1016/j.scitotenv.2015.02.011 korolija, b., borović, i., grimani, i., marinčić, s., jagačić, t., magaš, n. & milanović, m. (1977): osnovna geološka karta sfrj, tumač za listove lastovo k 33-46, korčula k 33-47 i palagruža k 33-57 [basic geological map of sfry 1:100000, geology of the lastovo, korčula, palagruža sheets – in croatian].– geološki zavod zagreb, savezni geološki zavod, beograd, 53p. kovačić, m., pavelić, d., vlahović, i., marković, f., wacha, l., kampić, š., rončević, s. & drempetić, d. (2018): pleistocene alluvial and aeolian deposits with tephra on the island of lopud (eastern mid adriatic, croatia): provenance, wind regime, and climate controls.– quaternary international, 494, 92–104. doi: 10.1016/j.quaint.2017.11.054. latrille, c., elsass, f., van oort, f. & denaix, l. (2001): physical speciation of trace metals in fe-mn concretions from a rendzic lithosol developed on sinemurian limestones (france).– geoderma, 100/1-2,127–146. doi: 10.1016/s00167061(00)00083-5 liu, f., colombo, c., adamo, p., he, j.z. & violante, a. (2002): trace elements in manganese–iron nodules from a chinese alfisol.– soil science society of america journal, 66, 661–670. doi: 10.2136/sssaj2002.6610 martinović, j. (1982): pedološka karta sfrj mjerilo 1:50 000, list mljet 1 [pedological map of sfry 1:50000, mljet sheet – in croatian].– projekt i savjet za izradu pedološke karte sr hrvatske, zagreb. mehra, o.p. & jackson, m.l. (1960): iron oxide removal from soils and clays by a dithionite-citrate system buffered with sodium bicarbonate.– clays clay minerals, 7, 317–327. doi: 10.1016/b978-0-08-009235-5.50026-7 moore, d.m. & reynolds, r.c. (1989): x-ray diffraction and the identification and analysis of clay minerals.– oxford university press, inc.,new york, 332 p. morelli, g., gasparon, m., fierro, d., hu,w.p. & zawadzki, a. (2012): historical trends in trace metal and sediment accumulation in intertidal sediments of moreton bay, southeast queensland, australia.– chemical geology, 300–301, 152–164. doi: 10.1016/j.chemgeo.2012.01.023 munsell soil color charts (1994): macbeth division of kollmorgen instruments.– new windsor, new york, usa. neaman, a., martinez, c.e., trolard, f. & bourrie, g. (2008): trace elements associations with fe-mn oxides in soil nodules: comparison of selective dissolution with electron probe microanalysis.– applied geochemistry, 23, 778–782. doi: 10.1016/j.apgeochem.2007.12.025 nemati, k., abu bakar, n.k., radzi abas, m. & sobhanzadeh, e. (2011): speciation of heavy metals by modified bcr sequential extraction procedure in different depths of sediments from sungai buloh, selangor, malaysia.– journal of hazardous materials, 192/1, 402–410. doi: 10.1016/j.jhazmat.2011.05.039 palumbo, b., bellanca, a., neri, r. & roe, m.j. (2001): trace metal partitioning in fe–mn nodules from sicilian soils, italy.– chemical geology, 173/4, 257–269. doi: 10.1016/s0009-2541(00)00284-9 pavelić, d., kovačić, m., vlahović, i., mandić,o., marković, f. & wacha, l. (2014): topography controlling the wind regime on the karstic coast: late pleistocene coastal calcareous sands of eastern mid-adriatic, croatia.– facies 60/4, 843–863. doi: 10.1007/s10347-014-0411-7 perez-huerta, a. & sheldon, n.d. (2006): pennsylvanian sea level cycles, nutrient availability, and brachiopod community structure.– paleogeography, palaeoclimatology, palaeoecology, 230/3, 264–279. doi: 10.1016/j.palaeo.2005.07.020 razum, i., miko, s., ilijanić, n., hasan, o., šparica miko, m., brunović, d. & v. pawlowsky-glahn, v. (2020): a compositional approach to the reconstruction of geochemical processes involved in the evolution of holocene marine flooded coastal karst basins (mljet island, croatia).– applied geochemistry, 116, 104574. doi: 10.1016/j.apgeochem.2020.104574 rogan šmuc, n., dolenec, t., kramar, s. & mladenović, a. (2018): heavy metal signature and environmental assessment of nearshore sediments: port of koper (northern adriatic sea).– geosciences, 8/11, 398. doi: 10.3390/geosciences8110398 rubinić, v., lazarević, b., husnjak, s. & durn, g. (2015): climate and relief influence on particle size distribution and chemical properties of pseudogley soils in croatia. – catena, 127, 340–348. doi: 10.1016/j.catena.2014.12.024 schwertmann, u. (1964): differenzierung der eisenoxide des bodens durch photochemische extraktion mit saurer ammoniumoxalat-lösung.– z. pflanzenernähr. bodenkund., 105, 194–202. doi: 10.1002/jpln.3591050303 sheldon, n.d. (2006): abrupt chemical weathering increase across the permian-triassic boundary.– paleogeography, palaeoclimatology, palaeoecology, 231/3–4, 315–321. doi: 10.1016/j.palaeo.2005.09.001 sheldon, n.d. & tabor, n.j. (2009): quantitative paleoenvironmental and paleoclimatic reconstruction using paleosols.– earth-science reviews, 95/1–2, 1–52. doi: 10.1016/j.earscirev.2009.03.004 soil science division staff (2017): soil survey manual.– in:ditzler, c., scheffe, k. & monger, h.c. (eds.): usda handbook 18 government printing office, washington, d.c. sondi, i., juračić, m., prohić, e. & pravdić, v. (1994): particulates and the environmental capacity for trace metals: a small river as a model for a land-sea transfer system: the raša river estuary.– science of the total environment, 155/2, 173–185. doi: 10.1016/0048-9697(94)90290-9 sondi, i. & juračić, m. (2010): whiting events and the formation of aragonite in mediterranean karstic marine lakes: new evidence on its biologically induced inorganic origin.– sedimentology, 57/1, 85–95. doi: 10.1111/j.1365-3091.2009.01090.x sondi, i., mikac, n., vdović, n., ivanić, m., furdek, m. & škapin, s.d. (2017): geochemistry of recent aragonite-rich sediments in mediterranean karstic marine lakes: trace elements as pollution and palaeoredox proxies and indicators of authigenic mineral formation.– chemosphere, 168, 786–797. doi: 10.1016/j.chemosphere.2016.10.134 surić, m., juračić, m., horvatinčić, n. & krajcar bronić, i. (2005): late pleistocene-holocene sea-level changes and pattern of karstic coasts submersionrecords from submerged speleothems along the eastern adriatic coast (croatia).– marine geology, 214/1–3, 163–175. doi: 10.1016/j.margeo.2004.10.030 tomadin, l. (2000): sedimentary fluxes and different dispersion mechanisms of the clay sediments in the adriatic basin.– rendiconti lincei. scienze fisiche e naturali, 11/3, 161–174. doi: 10.1007/bf02904649 ure, a.m., quevauviller, ph., muntau, h. & griepink, b. (1993): speciation of heavy metal in soils and sediments. an account of the improvement and harmonisation of extraction techniques undertaken under the auspices of the bcr of the commission of the european communities.– international journal of environmental analytical chemistry, 51/1–4, 135–151. doi: 10.1080/03067319308027619 vodyanitskii, y.n., vasilev, a.a., vlasov, m.n. & korovushkin, a.v. (2009): the role of iron compounds in fixing heavy metals and arsenic in alluvial and soddy-podzolic soils in the perm area eurasian.– soil science, 42, 738–749. doi: 10.1134/s1064229309070047 2022 | 75/special issue | 349–363 | 10 figs. | 4 appendix tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the polymetallic ore deposits in the territory of the republic of north macedonia from the geotectonic, structural, magmatic and metallogenetic point of view belong to the large geotectonic and metallogenetic units such as the metallogenetic belts, provinces, zones, regions etc. the tethys-eurasian metallogenetic belt is of special importance in metallogenetic zoning, which combines polymetallic mineralization of different rank and intensity, but with similar magmatic and mineralization features (jankovic, 1977; serafimovski, 1993; moritz & baker, 2019). the polymetallic mineralization from the regional point of view belong to the alpine-balkan-carpathian-dinarides metallogenetic belt (heinrich & neubauer, 2002). the serbo-macedonian metallogenetic province, which occupies central parts of the balkan peninsula, is a large metallogenetic unit with typical polymetallic ore deposits in the territories of serbia, the republic of north macedonia and greece (jankovic et al.,1980; serafimovski, 1993; arvanitidis, 2010). the lece-chalkidiki metallogenetic zone is especially important for the temporal and spatial distribution of polymetallic ore deposits at the contact parts of the serbo-macedonian mass (smm) and the vardar zone (vz) including the macedonian ore deposits (jankovic, 1990; serafimovski, 1990; serafimovski, 1993; alderton & serafimovski, 2007). regional geotectonic structures nnw-sse and tertiary volcanic intrusions and extrusions are very important for the distribution of polymetallic ore deposits in the central part of the balkan peninsula, see also (arsovski & ivanov, 1977; karamata, 1983; serafimovski, 1993; serafimovski et al., 2003; jelenkovic et al., 2008; volkov et al., 2019). in the territory of the republic of north macedonia, polymetallic mineralizations are paragenetically related to the tertiary volcanic intrusions of calc-alkaline character (16-37 ma; harkovska et al., 1989; boev & yanev, 2001; schefer et al., 2011), as well as the various tectonic structures trending in a nnw-sse direction (ivanov, general features of some polymetallic ore deposits in the republic of north macedonia todor serafimovski1, goran tasev1 and trajče stafilov2 1 university goce delcev, faculty of natural and technical sciences, stip, repubic north macedonia, str. goce delcev 89, 2000 stip; (todor.serafimovski@ugd.edu.mk) 2 ss cyril and methodius university, institute of chemistry, faculty of natural sciences and mathematics, arhimedova 5, 1000 skopje, north macedonia; (trajcest@pmf.ukim.mk) doi: 10.4154/gc.2022.27 abstract the general features of several important mineral deposits of polymetallic character in the republic of northern macedonia that have been actively exploited in the past are described. these include the buchim copper mine and sasa, zletovo and toranica lead-zinc mines, as well as some ore prospects that have been extensively explored for years. in addition, sites with known ore reserves, but which are not yet at the exploitation stage are presented, including plavica, ilovica, kadiica, borov dol and others. the elaborated ris-reserves program is used to affirm numerous parameters related to the definition of ore reserves in the deposits, and has now provided the opportunity for preparation of an overview which shows the major metallogenetic characteristics of the deposits with their techno-economic parameters. this approach enables affirmation of the potential of the polymetallic ore deposits in the republic of northern macedonia. 1966; serafimovski, 1993; serafimovski et al., 1997; dumurdzanov et al., 2005; schmid et al., 2013) and lithostratigraphic complexes representative of the serbo-macedonian massif and vardar zone in these terrains (burchfiel et al., 2008a; burchfiel et al., 2008b; lehmann et al., 2013; petrušev et al., 2021). 2. regional geotectonic and metallogenic setting of the macedonian polymetallic ore deposits the studied polymetallic deposits in the republic of north macedonia belong to two large geotectonic units; the vardar zone to the west and to the east the serbian-macedonian massif and they occupy the central parts of the balkan peninsula extending in a general northwest-southeast direction. the geological and geotectonic setting of these two large geotectonic units has been studied by dimitrijevic (1958), jankovic (1977), arsovski & ivanov (1977), serafimovski (1993), dumurdzanov et al (2005), robertson et al., (2009). ), lehmann et al., (2013), schimdt et al., (2013), antic et al., (2016) and šoster et al., (2020). the vardar zone is treated as a zone of ophiolitic melange, while the serbian-macedonian massif is described as a rigid mass built of precambrian rocks that make up the base and palaeozoic shales. in the post-collision processes in both settings, oligo-miocene volcanism took place (boev & yanev, 2001) with which the polymetallic deposits in macedonia and adjacent regions are associated (serafimovski et al, 2003; alderton & serafimovski, 2007 fig. 1). from a metallogenetic point of view, the polymetallic mineralizations on the territory of the republic of north macedonia belong to a part of the lece-chalkidiki metallogenetic zone, which is completely defined by serafimovski (1990), and it covers the contact parts between the vardar zone and the serbomacedonian massif (fig. 1), while the other part belongs to the article history: manuscript received may 31, 2022 revised manuscript accepted august 17, 2022 available online october 17, 2022 keywords: polymetallic deposits, ore minerals, ore reserves, metallogeny mailto:todor.serafimovski@ugd.edu.mk mailto:trajcest@pmf.ukim.mk g eo lo gi a c ro at ic a geologia croatica 75/3350 metallogenetic zone besna kobila-osogovo-thassos defined by serafimovski (1990) and aleksandrov (1992). this zone is completely located in the terrains of the serbo-macedonian massif. both zones have a general direction of northwestsoutheast beginning in serbia and continuing through macedonia to northern greece. their main features are tertiary volcanic rocks, regional fault structures with a northwest-southeast direction and polymetallic mineralizations such as lead, zinc, copper, gold, silver, molybdenum and others. the first data for the lecechalkidiki zone appear in the works of jankovic et al (1980), and later in the works of serafimovski (1993), alderton & serafimovski (2007) and volkov et al. (2019), while for the besna kobila-osogovo-thassos metallogenetic zone more detailed information can be found in the works of tasev (2010) and tasev et al. (2019). 3. polymetallic ore deposits in the republic of north macedonia almost all alpine polymetallic ore deposits in the republic of north macedonia are related to the major geotectonic units (vardar zone-vz and serbo-macedonian mass-smm) and metallogenetic units (serbo-macedonian metallogenic province). the enclosed lece-chalkidiki and besna kobila-osogovo-thassos metallogenetic zones have an emphasized significance in regard to the polymetallic ore deposits (fig. 2). in terms of the production of lead, zinc and copper in the territory of the republic of north macedonia the ore regions of kratovo-zletovo, sasa-toranica, damjan-buchim, are particularly important as well as the ore fields kadiica and ilovica (serafimovski, 1993; tasev, 2010; forward et al., 2017). the ore veins in the zletovo deposit, as well as the quartz-graphite series in the sasa and toranica deposits are bountiful from the aspect of lead and zinc production (serafimovski & aleksandrov, 1995). copper ores are abundant in the buchim (čifliganec, 1993) and borov dol (volkov et al., 2010; gjorgiev, 2020) , while in terms of potentiality, the plavica (serafimovski et al., 2017), kadiica (tasev, 2010 ) and ilovica deposits (forward, 2017) are interesting. some of the more significant metallogenetic characteristics of these deposits are presented in the following section. 3.1. plavica the area where the plavica deposit mineralization is located is a classic volcanic cone, which is part of the famous tertiary volcanism in the zletovo-kratovo volcanic area (stojanov, 1980). it consists of ignimbrite, dacite-andesite volcanic tuff, breccia and dacite-andesite as well as quartz-latite intrusions which form the figure 1. the location of tertiary volcanics and major metallogenic units in the southern part of the balkan peninsula (after alderton & serafimovski, 2007). g eologia c roatica serafimovski et al.: general features of some polymetallic ore deposits in the republic of north macedonia 351 figure 2. location of the polymetallic deposits in the territory of the r. n. macedonia (after tasev, 2003). wmz-western macedonian zone; pm-pelagonian massif; smm-serbo-macedonian massif figure 3. schematic genetic model of the plavica cu-au polymetallic ore deposit (after serafimovski et al., 2017). hs-high sulfidization; op-opalitization g eo lo gi a c ro at ic a geologia croatica 75/3352 basis of the lithological structure of the plavica volcanic apparatus (serafimovski et al., 2017; fig.3), which resembles a typical volcanic caldera that is degraded on its southern side (markovic, 1971; serafimovski, 1990). the general characteristic of the mineralized part of the plavica is the intense hydrothermal alteration which is dominated by kaolinization, sericization, silicification and allunization. several types of mineralization have been identified as part of a long research process that began intensively in 1971 and continues to this day with some interruptions. porphyry copper mineralizations have been of primary interest, but the remains of the old mining (primarily adits) attest to the fact that the quartz-pyriteenargite veins were exploited in roman times and in the period after world war ii (ivanov & denkovski, 1978; ivanov & denkovski, 1980). gold-bearing mineralizations in the quartz-alunite zones (vuggy silica) are of economic interest with the gold content of up to 3 g/t au (serafimovski & rakic, 1999). in the northwestern and southeastern peripheral parts of the mineralized volcanic apparatus, thin lead-zinc veins have been registered, which continue towards the southeast and the zletovo deposit. the economic parameters for the plavica deposit were prepared in accordance to selection criteria parameters geological criteria, social licensing, environmental management, project permitting, skills availability (appendix 1 – table 1 and table 2, which were adjusted to republic north macedonian standard) and their summary is in appendix 2; table 1. 3.2. buchim buchim has long been the only copper mine not only in macedonia, but also in the lece-chalkidiki zone. copper ores of the porphyry type with characteristically low contents of 0.25% cu and 0.3 g/t au have been exploited for more than 40 years (čifliganec, 1993; volkov et al., 2010). the porphyry copper ores in the buchim deposit are spatially localized around the andesitic intrusions in the precambrian gneiss and amphibolite (serafimovski, 1993). the tertiary volcanic intrusions aged 27-24 ma (lehmann et al., 2013) intruded in the form of dykes and necks in the precambrian complex 27-24 ma ago. three types of copper mineralization are distinguished in the buchim deposit: primary chalcopyrite, secondary deposits? in the cementation zones (chalcocite-covellite; secondary sulfide enrichment) and a mixed deposit localized mainly in the vrsnik ore body (čifliganec, 1987; čifliganec, 1993; strmić palinkaš et al., 2022). cu-au mineralization is associated with hydrothermal alteration assemblages within and around the ore body as it is shown for the youngest buchim ore body of vršnik (strmić palinkaš et al., 2022). the productive remaining mineralization of the porphyry ores in the buchim mine is located in the bunardzik and cukar 2 east ore bodies (fig. 4). the potential of the buchim ore deposit from the aspect of primary mineralization can be observed below the 405 m level, where the mineralization shows continuity in distribution. the economic parameters for the buchim deposit were prepared in accordance to selection criteria parameters geological criteria, social licensing, environmental management, project permitting, skills availability (appendix 1 – table 1 and table 2, which were adjusted to the republic of north macedonia standard) and their summary can be found in appendix 2; table 1. 3.3. borov dol the borov dol deposit spatially belongs to the vardar zone different phases of tertiary volcanic rocks, 32-27 ma , where stratified volcanic tuffs and volcanic breccia participate in its lithological construction (tudzarov, 1993; lehmann et al., 2013). porphyry copper mineralization is localized around the fine-grained andesite that has intruded the coarse-grained altered figure 4. a 3d model of the cu grades of bunardzik and chukar ore bodies within the buchim mine, looking northeast (after gray et al., 2017). g eologia c roatica serafimovski et al.: general features of some polymetallic ore deposits in the republic of north macedonia 353 andesite (fig. 5) containing copper mineralization averaging 0.3% cu and 0.3 g / t au (serafimovski, 1993). kaolinization, silicification and sericitization are the most intense hydrothermal alterations of the volcanic rocks while the higher parts are affected by epidotization, chloritization and limonization (knežević et al., 1975; gjorgjiev, 2020). the porphyry copper mineralization style is defined by a genesis study of the borov dol deposit, especially fluid inclusions, isotope compositions, geochronological and alteration type studies. primary ore solutions were defined by carbon and oxygen isotopes (tudzarov & serafimovski, 1994; tudzarov & serafimovski, 1995) and sources of metal by the sulfur isotope compositions (serafimovski, 1993; serafimovski & tasev, 2013; gjorgjiev, 2020). geochronological data were defined by lehmann et al., (2013). the economic parameters for the borov dol deposit were prepared in accordance to selection criteria parameters geological criteria, social licensing, environmental management, project permitting, skills availability (appendix 1 – table 1 and table 2, which were adjusted to the republic of north macedonia case) and their summary can be found in appendix 2; table 1. 3.4. kadiica kadiica-bukovic is one of the few, if not the only, porphyry copper mineralization located in the easternmost metallogenetic zone of besna kobila-osogovo-thassos, which is mainly dominated by the mineralization of lead and zinc sulfides, sometimes followed by the appearance of scheelite and molybdenite (jankovic & petkovic, 1974; jankovic et al., 1980; serafimovski et al., 1995; tomson et al., 1998). the geological composition of the kadiica deposit is represented by eocene-oligocene quartzlatites (35-27 ma; harkovska, 1984; harkovska et al., 1989) and hydrothermally altered schist (stojanov et al., 1995; tasev, 2010). copperbearing mineralization is mainly manifested as secondary chalcocite and covellite that occur in the form of pyrite coatings and less frequently chalcopyrite in the form of stockworks and disseminations (tasev, 2010). the identified mineralizations clearly define the zones of leaching and secondary sulfide enrichment (fig. 6). morphostructural analysis classifies ore bodies as poor hypogenic copper mineralizations (<0.15% cu) and richer ore bodies of secondary sulfide enrichment of copper (with average copfigure 5. a visual presentation of assay and modelled borov dol copper grades (after gray et al., 2017). g eo lo gi a c ro at ic a geologia croatica 75/3354 per concentrations of around 0.22% cu). hypogenic mineralization is of a disseminated stockwork character with variable contours. at depth, copper mineralization occupies a space between the 90 and 220 m levels (tasev, 2010). calculated ore reserves and the associated economic parameters of bukovik-kadiica were prepared in accordance to selection criteria parameters geological criteria, social licensing, environmental management, project permitting, skills availability (appendix 1 – table 1 and table 2, which were adjusted to the republic of north macedonia case) and summarised in appendix 2; table 1. the study of the fluid-inclusions within quartz associated with the mineralizations confirmed that the formation of the copper mineralization in the kadiica deposit took place over a wide temperature range (627-326 °c) and with three main compositional phases of the ore solutions. the solutions were characterized by different salinities i.e. from 6-16 wt% nacl through 3-24 wt% nacl equiv to those with 32-45 wt% nacl (tasev, 2010; tasev et al., 2018) 3.5. ilovitsa the porphyry cu deposit of ilovitsa is another example of mineralization within the lece-chalkidiki-thassos metallogenic zone (serafimovski, 1990; heinrich & neubauer, 2002; tasev, 2003). the geological basis of the ilovitsa ore deposit is composed of precambrian (two-mica gneiss, biotite gneiss, muscovite gneiss, mica-schist and amphibolite) and riphean-cambrian (amphibolite and epidote-quartz-sericite-chlorite schist) rocks. at the time of the palaeozoic (hercynian orogeny) figure 6. a geological cross-section at bukovik-kadiica (after tasev, 2010). note: exploration drill holes 09 (depth 423 m), 10 (depth 400 m) and 11 (263.5 m) figure 7. ilovitsa ore deposit geological cross-section and alterations, west-east cross section (after forward et al., 2017). g eologia c roatica serafimovski et al.: general features of some polymetallic ore deposits in the republic of north macedonia 355 this foundation was intruded by granite in the form of batholiths. later in the late eocene-oligocene this area was protruded by dacites and andesites, which are characterized by mineralization of economic or non-economic character (fig. 7). the tertiary rocks are affected by hydrothermal alterations, which in places lead to the complete destruction of the primary structures and change of the initial mineral composition. these alterations are manifested by an advanced argillic zone, phyllic zone and potassic core, while silicification, sericitization, alunitization, opalization and chloritization were rarely determined (fig. 7). the mineralization is associated spatially and genetically with a granodiorite stock that occupies a surface area of 100 x 200 m (100 m to the north-south and 200 m to the east-west), while at depth can be detected down to approximately 700 m. the main ore minerals of the stockwork mineralization are: chalcopyrite, pyrite, bornite, native gold, magnetite, haematite, tennantite, galena, sphalerite, chalcocite, covellite, etc. a cementation zone formed below the oxidation zone, and has a thickness in the range of 3.5 to 9 m, and the main ore minerals are chalcocite and covellite (serafimovski, 1993; serafimovski & tasev, 2011). the economic parameters for the ilovitsa deposit were prepared in accordance to selection criteria parameters geological criteria, social licensing, environmental management, project permitting, skills availability (appendix 1 – table 1 and table 2, which were adjusted to the republic of north macedonia case) and are summarised in appendix 2; table 1. 3.6. zletovo the lead-zinc deposit of zletovo is a typical vein type hydrothermal deposit of subvolcanic character, localized in the ignimbrite and tuff of tertiary age which are intruded by dacite and andesite dykes and necks [serafimovski, 1993; serafimovski & aleksandrov, 1995; tasev, 2003]. the ore veins in the zletovo deposit have a general trend of northwest-southeast and belong to the group of single or simple ore veins (fig. 8). only ore veins 13 and 10 have opposite directions of strike and slip, but have the same mineral characteristics as the other ore veins (serafimovski, 1990).. the third shape of the ore bodies in the zletovo mine is the ore pillars or the thickening of the ore veins in their surface parts. these are parts of ore veins with a high concentration of predominantly galena ores, and the lead content is about 0.15% pb. on average, the thickness of the ore veins ranges from 1 to 3 m, and the salband parts of the veins are mostly kaolinized, silicified and carbonized. zoning of the basic ore metals in the ore veins going from surface to depth is characteristic. in the superficial parts, lead dominates, followed by a transition with pb + zn, then pb + zn itself and in the deeper parts zn + cu [efremov, 1993; tomson et al., 1998]. the mineral association is dominated by galena and sphalerite, followed by chalcopyrite, pyrite, tetrahydrite, tennantite, arsenopyrite, argentite, polybasite. it is regularly associated with quartz, siderite and barite with kaolinite [serafimovski 1990; serafimovski et al., 2006]. the content of lead and zinc and their economic parameters within the zletovo ore deposit were prepared in accordance to selection criteria parameters geological criteria, social licensing, environmental management, project permitting, skills availability (appendix 1 – table 1 and table 2, which were adjusted to the republic of north macedonia case) and their summary can be found in appendix 2; table 2. from the genetic point of view zletovo can be defined as a sub-volcanic hydrothermal vein type ore deposit with pb-zn mineralization localized within the volcanic tuff and ignimbrite of andesite and dacite composition. a fluid inclusion study confirmed the hydrothermal character of the ore-bearing fluids dominated by their chloride composition with homogenization temperatures within the range of 335–145°c and salinities from 4.4 to 8.6 wt% eqv. nacl (tasev & serafimovski, 2012; tafigure 8. a geological cross section through the zletovo mine (after aleksandrov, 1992). g eo lo gi a c ro at ic a geologia croatica 75/3356 sev et al., 2019), while within the lower temperature cleophane parageneses, salinity ranged between 10-25 wt% eqv. nacl. sulfur isotope composition in galena and sphalerite has an endogenic origin while the carbon isotope composition points to the participation of meteoric waters in ore-bearing fluids (mudrinić & serafimovski, 1990-91). 3.7. toranica the lead-zinc ore deposit of toranica belongs to the group of deposits that were explored in the period between 1974 1978, when the mine started active exploitation (bogojevski & gasteovski, 1990). the ore is located in precambrian metamorphic rocks such as gneiss and quartz-graphite schist, intruded by tertiary volcanics dated at 32 ma (tasev et al., 2005). productive lead-zinc ore is localized predominantly in quartz graphite schists in the form of elongated pseudolayers and lenses in the so-called hanging wall gneiss (bogojevski, 1990; dobrovolskaya & stankovski, 1997; stankovski, 1997). the contact ore bodies between gneiss and quartz latite, as well as between quartz graphite schist and quartz latite, are less significant than the so-called central ore bodies (fig. 9) localized in quartz graphite schist (serafimovski & aleksandrov, 1995). the qualitative-quantitative characteristics of the ores in the toranica deposit were prepared in accordance to selection criteria parameters geological criteria, social licensing, environmental management, project permitting, skills availability (appendix 1 – table 1 and table 2, which were adjusted to the republic of north macedonia case) as summarised in appendix 2; table 2. analysis of the mineral compositions, ore textures and structures as well as the chemical properties of the main ore sulfides defines the following mineral parageneses: quartz-pyrrhotitеgalеna-sphalerite, pyrite-chalcopyrite-sphalerite, quartz-epidotesphalerite-galena, quartz-calcite. the slight difference in the parageneses is defined by sulfide predominance. parageneses of pyrite, sphalerite, galena, quartz, calcite, epidote and actinolite are represented by several generations. the composition of sphalerite is discriminated from early to late parageneses by the percentage of fe, mn, cd, cu, while galena has a variable composition of bi, ag, se. the rock-forming minerals differ in the percentage of fe and mn (serafimovski & tasev, 2006). geochemical properties of minerals and their structural relationship indicate the repeated input of ore-forming solutions (serafimovski et al., 2006). figure 9. a geological section through the central part of the toranica ore deposit (after stankovski, 1997) 1) ore body, 2) pb-zn mineralization, 3) cipolino marble, 4. quartzgraphite schist, 5) gneiss, 6) quartzlatite, 7 drill hole. g eologia c roatica serafimovski et al.: general features of some polymetallic ore deposits in the republic of north macedonia 357 a fluid inclusion study of quartz, calcite and sphalerite, confirmed the hydrothermal character of ore-bearing fluids and the intermittent input of the ore-bearing solutions. the initial stage occurred at 320-370°c and higher salinities (14-16% wt eqv. nacl; serafimovski et al., 1997), while the later ore-forming stage is characterized by temperatures ranging between 190250°c and respective lower salinities (4-9 %wt eqv. nacl). such numbers indicated later ore forming stages when the ore-bearing capacity decreased significantly. a study of δ34s in pyrite, sphalerite and galena from the toranica ore deposit showed a narrow range of variation (+3.15 to 7.54 ‰ δ34s, -0.73 to +7.23‰ δ34s) respectively for pyrite, sphalerite and galena (+0.72 to 5.11‰ δ34s), representing a magmatic origin of the sulfur (serafimovski et al., 1997). a discrepancy of +14‰ δ34s (found in pyrite from quartz-graphite schist) was attributed to a sedimentary origin (ohmoto & rye, 1979). 3.8. sasa the sasa ore deposit, from an economic perspective is the most important lead-zinc deposit in the republic of north macedonia, and is listed in the group of several major deposits in europe. the geological structure of the deposit consists of precambrian gneiss, lower palaeozoic quartz-graphite schist, chlorite-sericite figure 10. a geological plan and cross section through the sasa ore deposit (after serafimovski & aleksandrov, 1995). a. level xv, kozja river; b. geological cross section svinja river; c. geological cross section golema river; d. geological cross section kozja river; 1. ore body; 2. quartz-latite; 3. cipoline; 4. quartz-graphite schist; 5. gneiss. g eo lo gi a c ro at ic a geologia croatica 75/3358 schist with intercalation of limestone, calcite schist and quartzlatite dykes of tertiary age (bogojevski, 1964; aleksandrov, 1992). lead-zinc mineralization is localized mainly within the quartz-graphite series with calcite skarn, johansenite and bustamite skarn (fig. 10). the concentration of lead and zinc in some pseudo-layers and lenses in places is very high and exceeds 20% pb + zn, with a silver content of over 50 g/t ag (serafimovski & aleksandrov, 1995). this productive zone extending from the northwest to the southeast and a southwest dipping slope at depth can be followed for more than 1200 m with an average width of 50 m. the main ore minerals and bearers of lead-zinc mineralization are galena and sphalerite, regularly followed by a lot of pyrrhotite, pyrite and silver-bearing minerals (aleksandrov et al., 1990). skarn paragenesis consists of garnet, large johansenite, bustamite, ilvaite, epidote and in places calcite and aragonite in the lower parts (serafimovski & aleksandrov, 1995; aleksandrov et al., 1999; strmić-palinkaš et al., 2013; strmić-palinkaš et al., 2018) the qualitative-quantitative characteristics of the ores in the sasa deposit were prepared in accordance to selection criteria parameters geological criteria, social licensing, environmental management, project permitting, skills availability (appendix 1 – table 1 and table 2, which were adjusted to the republic of north macedonia case) and are summarised in appendix 2; table 2. the origin of lead-zinc ores in the sasa mine, stratified in the palaeozoic quartz-graphite schist was interpreted as a syngenetic type tufar & strucal (1984). however, bogojevski (1964), aleksandrov (1992) defined this deposit as hydrothermal whereas the lead-zinc mineralization is localized in the calcite skarn. this thesis is also supported by strmićpalinkaš et al., (2018), who also analytically confirms hydrothermal lead-zinc ores within the calcite and bustamite skarn. our position is based on lead, sulfur, carbon and oxygen isotope analyses data and fluid-inclusions that define the primary origin of ore metals and ore fluids and the hydrothermal character of the deposit. most of the analyzed samples indicate the pronounced anomaly of lead isotopic composition (uranogenic or torogenic; serafimovski et al., 1997). the anomaly (18.589-18.700 206pb/204pb, 15.680-15.827 207pb/204pb and 38.929-38.990 208pb/204pb) could be attributed to contamination by surrounding rocks or due to the redeposition of lead. analysis of sulfur in sulfides from the sasa ore deposit shows narrow ranges of variation. in pyrite values were determined from +4.34 to +6.94‰ δ34s, in sphalerite -1.22 to +5.18‰ δ34s, in galena from +2.13 to +3.64 ‰ δ34s, pyrrhotite from +1.80 to +3.97 ‰ δ34s and chalcopyrite from +4.39 to +4.41 ‰ δ34s, which together indicates a magmatic origin of s (ohmoto & rye, 1979; serafimovski et al., 1997). the study of the isotopic composition of carbon from the sasa ore deposit (from -5.50 to -1.48 ‰ δ13c) indicates its endogenous origin (ohmoto & rye, 1979; serafimovski et al., 1997). the δ18o isotopic composition results varied from +16.79 to +23.21‰ δ18o, probably indicating the significant fractionation of oxygen from the place of mineral material deposition and its mobilization from carbonates (serafimovski et al., 1997), which is very representative for similar mid to low-temperature hydrothermal ore deposits where meteoric water formed a significant part of hydrothermal solutions (ohmoto & rye, 1979). a study of fluid inclusions in quartz determined primary and secondary fluid inclusions (strmić palinkaš et al., 2013). primary fluid inclusions were characterized as two-phase (l+v) inclusions with variable shapes and a degree of fill of 0.75. temperatures of homogenization vary from 270°c to 300°c while salinities were on the lower end (6.3-7.9 wt% equ nacl). post-mineralization minerals analysis, mainly in calcite, proved homogenization temperatures of 125-233°c and even lower salinities, which suggests deposition from colder and relatively diluted ore-bearing fluids. 4. mining potential as can be seen from published data by the world mining data (reichl & schatz, 2022), the republic north macedonia contributes to the world mining of copper, lead and zinc at relatively fair level. between 2019 and 2020, copper, lead and zinc were officially listed, ranking republic north macedonia on position 49 and 47 in regards to copper production, position 15 and 13 in regards to lead production and position 31 in regards to zinc production (reichl & schatz, 2022). aforementioned data based on the real geological potential identified for the three commodities, copper, lead and zinc, republic north macedonia is capable of performing even at higher level. here we are discussing, the three indicators of mining potential, grouped by commodity. 4.1. indicator 1: world production ranking 4.1.1. copper the world production of copper was 20 788 363 metric tons in 2019, and at the same time, copper production originating from the republic of north macedonia reached 6 625 metric tons, which is 0.03% of the total production in 2019. bearing in mind the reserves and resources of the active copper deposits (mines) within the republic of north macedonia and the annual production of 4 to 5 mt of ore annually, a mine lifetime of more than 20 years looks very realistic. at the present rate of copper production (2019-2020), macedonia ranks in the lower part of the list (reichl & schatz 2022), partly due to the fact that in the respective period there was a transition from the production at the buchim mine to the newly developed borov dol mine. 4.1.2. lead with regard to lead, annual production from macedonia amounts to 44 930 metric tons compared to the 4 747 983 metric tons of world production. this represents 0.95% of world production of lead. bearing in mind only the reserves of the active lead (and zinc) mines within the republic of north macedonia (> 31 mt of ore)) and annual production of 1.5-2 mt of ore annually, a mine lifetime of more than 15 years looks very realistic, even not considering the resources. at the present rate of lead production (2019-2020), macedonia ranks in the top 33 % of the world producer rankings list (reichl & schatz 2022). 4.1.3. zinc the world production of zinc reached 12 608 299 metric tons in 2019, and at the same time, zinc production in the republic of north macedonia was 31 750 metric tons, (0.25% of total world production in 2019). due to the fact that zinc is exploited together with lead from the lead-zinc mines (toranica, sasa and zletovo), reserves of more than 31 mt of lead-zinc ore and an annual production of 1.5-2 mt of ore should be sufficient for a mine lifetime of more than 15 years (combined). this mine life projection g eologia c roatica serafimovski et al.: general features of some polymetallic ore deposits in the republic of north macedonia 359 doesn’t consider resources. at the present rate of zinc production (2019-2020), macedonia ranks in the middle of the world producers ranking list (reichl & schatz 2022). 4.2. indicator 2: selfsufficiency recently one of the most vital issues related to the mineral commodities industry became the topic of self-sufficiency. namely, we cannot ignore the fact regarding the import of necessary mineral commodities. with regard to copper, lead and zinc we would like to emphasize that the republic of north macedonia’s, according to official statistics (simovski, 2020), imports are either very low or absent for these commodities. in contrast, the export of the aforementioned commodities is at significant levels. before presenting numerical data we would like to stress that due to the proximity of smelting facilities and ports for export, the majority of copper, lead and zinc concentrated production is exported to the neighbouring country of bulgaria, although certain quantities are coming back to macedonia due to industry needs. of a total copper concentrate production if 31 226 metric tons and 28 484 metric tons (in 2019 and 2020, respectively; simovski, 2020) around 97-98% was exported. lead concentrate production amounted to 60 154 metric tons and 62 400 metric tons (in 2019 and 2020, respectively; simovski, 2020) of which around 86-97% was exported while in the case of zinc concentrate production (31 254 metric tons and 46 959 metric tons in 2019 and 2020, respectively; simovski, 2020) around 49-77% was exported. 4.3. indicator 3: economic contribution the mining potential of the republic of north macedonia can also be expressed through economic parameters. as can be seen in simovski (2020), the export of copper, lead and zinc from active mines in the republic of north macedonia, expressed in monetary units, reaches 163 256 000 us$, which compared with the total exports for 2019 of 7 185 157 000 us$ represents a 2.27% contribution. however, in regards to the economic importance of this industry, the contribution to the gross domestic product of the republic of north macedonia in 2020 of up to 1.8% is more illustrative, while the related industry category that includes mining and quarrying, manufacturing, electricity, gas, steam and air conditioning supply as well as water supply; sewerage, waste management and remediation activities contributed up to 18.1% in 2019 and 17.3% in 2020 of total gdp simovski, 2020). also, here we should take into account the estimated values of reserves/resources of the kadiica ore deposit, which are up to 369 000 000 us$ (as of year 2014), the plavica ore deposit of up to 622 000 000 us$ (as of year 2014) and the ilovitsa ore deposit of up to 3 500 000 000 us$ (as of 2011), which makes an impressive sum of approximately 4.5 billion us $. in the case of the kadiica, plavica and ilovitsa ore deposits we would like to emphasize that calculations were based on their respective years of calculation of reserves, but since then metal prices have increased substantially, which should increase their values accordingly. 5. conclusion the polymetallic ore deposits (lead, zinc, copper, gold and silver) in the territory of the republic of north macedonia are spatially related to the vardar zone and the serbo-macedonian massif as the two large geotectonic units of regional scale, and are paragenetically connected to the tertiary complexes which belong to the metallogenetic zones of lece-halkidiki and besna kobilaosogovo-thassos, both within the serbo-macedonian metallogenetic province. two types of lead-zinc deposits have been defined in the republic of north macedonia, a typical lead-zinc zletovo deposit and skarn pb-zn deposits at sasa and toranica, with the latter having the greater potential. porphyry copper deposits are located at plavica, buchim borov dol, kadiica and ilovitsa. the most important porphyry copper deposit is at ilovitsa, which belongs to the serbo-macedonian massif, with proven ore reserves of around 500 mt. ore reserves in the plavica, buchim and borov dol localities are in the order of 100 to 150 mt, which generally corresponds to the quantities of ore in the porphyry deposits within the lece-halkidiki zone, where the lece deposit in serbia and the skouries deposit in greece have similar features. all of them are located in the contact zones between the serbo-macedonian massif and the vardar zone and are a product of calc-alkaline volcanic intrusions that were intruded at sub-volcanic levels. the kadiica deposit may be promising, but for now only porphyry mineralizations in the oxidation and cementation zones have been defined in that area, while the primary mineralizations need to be further explored. acknowledgement the proposed review article was part of the activities in the frame of the ris-reseerve project (https://eitrawmaterials. eu/project/reseerve/), funded by the eit rawmaterials, part of the european innovation institute (eit), funded by the european union. references alderton, h.m.d. & serafimovski, t. (2007): the geology and genesis of the plavica copper-gold deposit, macedonia.– applied earth science (trans. inst. min. metall. b), 116/2, 94–105. doi: 10.1179/174327507x167073 aleksandrov, m. (1992): metalogenetske karakteristike polimetalicnog rudnog polja sase-lstocna makedonija [metallogenetic characteristics of the sasa polymetallic ore field – in serbian].– phd thesis, university “sts. cyril and methodius”skopje, faculty of mining and geology, stip, 264 p. aleksandrov, m., mankov, s. & serafimovski, t. (1990): srebrenite minerali od olovno-cinkovoto naogaliste sasa istocna makedonija [siver minerals from the lead-zinc deposit sasa, eastern macedonia – in macedonia].– in: xii congress of geologists of yugoslavia, ohrid, 3, 86–102. aleksandrov, m., serafimovski, t. & m’nkov, s. (1999): silver-bearing contents and mode of occurence of silver in the sasa pb-zn deposit, eastern macedonia.– geologica macedonica, 12, 23–36. antić, m., peytcheva, i., von quadt, a., kounov, a., trivić, b., serafimovski, t., tasev, g., gerdjikov, i. & wetzel, a. (2016): pre-alpine evolution of a segment of the north-gondwanan margin: geochronological and geochemical evidence from the central serbo-macedonian massif.– gondwana research, 36, 523–544. doi: 10.1016/j.gr.2015.07.020 arsovski, m. & ivanov, t. (1977): neotectonics magmatism and metallogeny on the territory of yugoslavia.– in: janković, e. (ed.): metallogeny and platetectonics in the ne mediterranean. faculty of mining and geology, belgrade, 471– 482. arvanitidis, n. (2010): new metallogenetic concepts and sustainability perspectives for non-energy metallic minerals in central macedonia, greece.– bulletin of the geological society of greece, 43/5, 2437–2445. boev, b. & yanev, y., (2001): tertiary magmatism within the republic of macedonia: a review.– acta vulcanologica, 13/1–2, 57–71. bogojevski, k. & gateovski, v. (1990): koncentracija na korisnite metali /pbzn/ vo podinskata rudna zona na rudnoto ležište toranica, [concentration of useful pb-zn within footwall ore zone in the toranica ore deposit – in macedonian].– in: xii congres of geologists of jugoslavia, ohrid, 129–136. bogojevski, k. (1964): metalogenija vezana za tercijarni magmatizam u oblasti osogovo-besna kobila [metallogeny related to tertiary magmatism of the osogovo-besna kobila – in serbian].– phd thesis, faculty of mining and geology, belgrade, 322 p. bogojevski, k. (1990): strukturna gradba na podinskata rudna zona vo rudnoto ležište toranica [structural composition of the footwall ore zone within the torang eo lo gi a c ro at ic a geologia croatica 75/3360 ica ore deposit – in macedonian].– in: xii congres of geologists of jugoslavia, ohrid, 137–145. burchfiel, b.c., king, w.r., nakov, r., tzankov, t., dumurdzanov, n., serafimovski, t., todosov, a. & nurce, b. (2008a): patterns of cenozoic extensional tectonism in the south balkan extensional system.– in: husebye, e.s. (ed.): earthquake monitoring and seismic hazard mitigation in balkan countries. springer science+business media b.v., 3–18. doi: 10.1007/978-14020-6815-7_1 burchfiel, b.c., nakov, r., dumurdzanov, n., papanikolaou, d., tzankov, t., serafi movski, t., king, r.w., kotzev, v., todosov, a. & nurce, b. (2008b): evolution and dynamics of the cenozoic tectonics of the south balkan extensional system.– geosphere, 4, 919–938. doi: 10.1130/ ges00169.1 čifliganec, v. (1987): metalogenetske karakteristike ležišta bakra bučim u srpskomakedonskoj metalogenetskoj provinciji [metallogenetic features of the bučim copper deposit in the serbo-macedonian metallogenetic province – in serbian].– ph.d. thesis, faculty of mining and geology, belgrade, serbia, 190 p. čifliganec, v. (1993): rudišta i pojavi na bakar vo republika makedonija: tipovi i reonizacija [copper mineralization in the republic of macedonia: types and distribution patterns – in macedonian with extended summary in english].– university “sts. cyril and methodius” skopje, faculty of mining and geology stip, spec. issue, 1, 303 p. dimitrijevic, m.d. (1958): geološki sustav i struktura bujanovačkog granitskog masiva.–rasp. zav. za geol. i geof. istr. nr srbije, 7/7, 145. dobrovolskaya, m.g. & stankovski, r. (1997): structural-textural relations and succession of ore deposition in the toranica pb-zn deposit (macedonia).– geology of ore deposits c/c of geologiia rudnykh mestorozhdenii, 39, 79–92. dumurdzanov, n., serafimovski, t. & burchfiel, b.c. (2005): cenozoic tectonics of macedonia and its relation to the south balkan extensional regime.– geosphere 1, 1–22. doi: 10.1130/ges00006.1 efremov, i. (1993): metalogenija na kratovsko-zletovskata vulkanska oblast [metallogeny of the kratovo-zletovo volcanic area – in macedonian].– faculty of mining and geology, stip, university “sts. cyril and methodius”skopje, phd thesis, 286 p. forward, p., ligovski, m. & davies, r. (2017): resource modelling at the ilovica-štuka porphyry copper-gold deposit, eastern macedonia.– geologica macedonica, 31/1, 21–40. gjorgjiev, l. (2020): povekjefazno modeliranje na orudnuvanjeto vo borovdolskiot bakaren porfirski system [multiphase modelling of ore mineralization witjin the borov dol’s copper porphyry system – in macedonian].– university “goce delcev”-stip, faculty of natural and technical sciences, phd thesis, 262 p. gray, h.j., bird, c.s., meintjes, t. & trout, g. (2017): preliminary economic assessment for the buchim mine and borov dol property in macedonia.– moose mountain technical services, 43–101, 216. harkovska, a., yanev, y. & marchev, p. (1989): general features of the paleogene orogenic magmatism in bulgaria.– geologica balcanica, 19, 1, 37–72. harkovska, a. (1984): tertiary magmotectonic zones in southwest bulgaria. in:vozar, j. (ed.): magmatism of the molasse-forming epoch and its relation to endogenous mineralization: bratislava, geologicky ustav dioyza stura, 9–34. heinrich, c.a. & neubauer, f. (2002): cu–au–pb–zn–ag metallogeny of the alpine-balkan-carpathian-dinaride geodynamic province.– miner. depos., 37, 533–540. doi: 10.1007/s00126-002-0271-x ivanov, t. (1966): metalogenija juznog dela vardarske zone [metallogeny of the southern part ov the vardar zone – in serbian].– in: proceedings of the vith counceling, v. ii, ohrid, 424–448. ivanov, t. & denkovski, đ. (1978): geology of the metallogenetic knot plavicazlatica within the kratovo-zletovo area [geologija na metalogenetskiot jazel plavica-zlatica vo kratovsko-zletovskata vulkanska oblast – in macedonian].– in: ix congress of geologists of sfry, sarajevo, 565–570. ivanov, t. & denkovski, đ. (1980): hydrothermal alterations in the plavica–zlatica porphyry copper deposit in the kratovo–zletovo volcanic area. symposia of alteration of rocks and minerals [hidrotermalni alteracii vo porfirskoto leziste plavica-zlatica, vo kratovsko-zletovskata vulkanska oblast – in macedonian].– in: a 100 years of geological school and science in serbia. faculty of mining and geology, university in belgrade, 139–162. janković, s. (1977): the copper deposits and geotectonic setting of the thethyan eurasian metallogenetic belt.– mineralium deposita, 12, 37–47. janković, s. & petković, m. (1974): metallogeny and concepts of the geotectonic development of yugoslavia.– faculty of mining and geology, belgrade, 443–477. janković, s. (1990): types of copper deposits related to volcanic environment in the bor district, yugoslavia.– geol. rundsch., 79, 467–478. jankovic, s., petkovic, m., tomson, i. n. & krasov, v. (1980): porphyry copper deposits in the serbo-macedonian province, southeastern europe.– in: janković. s. & sillitoe, r.h: european copper deposits, sga-spec. publ. no. 1. unesco-igcp projects no. 169 and no. 60, 424–448. jelenković, r., kostić, a., životić, d. & ercegovac, m. (2008): mineral resources of serbia.– geologica carpathica, 59, 345–361. karamata, s. (1983): koncentracija nekih mikroelemenata u tercijarnim magmatitima istočnih delova jugoslavije povezanih sa njihovom geotektonskom pozicijom [concentration of some microelements in tertiary magmatites of eastern part of yugoslavia related to their geotectonic position – in serbian].– glas cccxxxv sanu, 49, 39–54. knežević-djordjević, v., karamata, s. & djorgjević, p. (1975): studija hidrotermalnih izmena oko rudnih pojava na lokalnosti borov dol [study of hydrothermal alterations around the ore occurrences in the borov dol locality – in serbian].– rudarsko geološki fakultet, laboratorija za petrologiju, beograd, 29 p. lehmann, st., barcikowski, j., von quadt, a., gallhofer, d., peytcheva, i., heinrich, c.a. & serafimovski, t. (2013): geochronology, geochemistry and isotope tracing of the oligocene magmatism of the bučimdamjan-borov dol ore district: implications for timing, duration and source of the magmatism.– lithos, 180/181, 216–233. marković, m. (1971): prilog poznavanja vulkanske morfologije kratovko-zletovske oblasti [contribution to knowledge about the volcanic morphology of the kratocozletovo volcanic area – in serbian].– geoloski anali balkanskog poluostrva, 36, 39–44. moritz, r. & baker, t. (2019): metallogeny of the tethyan orogenic belt: from mesozoic magmatic arcs to cenozoic back-arc and postcollisional settings in southeast europe, anatolia, and the lesser caucasus: an introduction.– economic geology, 114/7, 1227–1235. doi: 10.5382/econgeo.4683 mudrinić, c. & serafimovski, t. (1990–91): geochemical and geochronological examinations by isotopes in zletovo ore field.– geologica macedonica, 5/1, 105–120. ohmoto, h. & rye, r.o. (1979): isotopes of sulfur and carbon.– in: barnes, h.l. (ed.): geochemistry of hydrothermal ore deposits, 2nd ed. wiley & sons, inc., new york, 509–567. petrušev, e., stolić, n., šajn, r. & stafilov, t. (2021): geological characteristics of the republic of north macedonia.– geologica macedonica, 35/1, 49–58. doi: 10.46763/geol21351372049ep reichl, c. & schatz, m. (2022): world mining data 2022: iron and ferro-alloy metals, non-ferrous metals, precious metals, industrial minerals, mineral fuels.– (minerals production, vol. 37), federal ministry of agriculture, regions and tourism, republic of austria, vienna (checked on 5/10/2022). robertson, a., karamata, s. & saric, k. (2009): overview of ophiolites and related units in the late palaeozoic–early cenozoic magmatic and tectonic development of tethys in the northern part of the balkan region. ophiolites and related geology of the balkan region.– lithos, 108/1–4, 1–36. schefer, s., cvetkovic, fügenschuh, b., kounov, a., ovtcharova, m., schaltegger, u. & schmid, s.m. (2011): cenozoic granitoids in the dinarides of southern serbia: age of intrusion, isotope geochemistry, exhumation history and significance for the geodynamic evolution of the balkan peninsula.– international journal of earth sciences, 100, 1181–1206. doi: 10.1007/s00531010-0599-x schmid, s.m., bernoulli, d., fügenschuh, b., kounov, a., oberhänsli, r., schefer, s., van hinsbergen, d. & ustaszewski, k. (2013): similarities and differences between alps carpathians, dinarides–hellenides and anatolides–taurides.– egu, 15, 3525. serafimovski, t. & aleksandrov, m. (1995): lead and zinc deposits and occurrences in the republic of macedonia.– rgf, stip, 387 p. serafimovski, t. & rakić, s. (1999): new geochemical data concerning gold related to silification zones in the plavica volcanic structure, eastern macedonia.– in: stanley et al. (eds.): mineral deposits: processes to processing. balkema, roterdam, 585–588. serafimovski, t. & tasev, g. (2011): report for ore-microscopic explorations of the samples at the ilovica site – strumica.– faculty of natural and technical sciences, university “goce delcev”, stip, serafimovski, t. & tasev, g. (2013): ore-microscopic study of samples from the plavica deposit; department of mineral deposits.– faculty of natural and technical sciences, university “goce delcev”, stip, 411 p. serafimovski, t. (1990): metalogenija na zonata lece-halkidiki [metallogeny of the lece-chalkidiki zone – in macedonian].– ph.d. thesis, faculty of mining and geology, stip, 390 p. serafimovski, t. (1993): structural metallogenetic characteristics of the lece-chakidiki zone: types of mineral deposits and distribution.– special edition of rgf stip, 2, 328 p. serafimovski, t. & tasev, g. (2006): some contact metamorphic-metasomathic phases in the toranica pb-zn deposit, macedonia.– in: cherkasov, s.v. (ed.): understanding the genesis of ore deposits to meet demand of the 21st century: 12th quadrennial iagod symposium. moscow, 120 p. serafimovski, t., dolenec, t. & tasev, g. (2006): actinolite-phengite-chlorite metasomatites from the toranica pb-zn ore deposits in macedonia.– rmz-materials and geoenvironment, 53/4, 445–453. g eologia c roatica serafimovski et al.: general features of some polymetallic ore deposits in the republic of north macedonia 361 serafimovski, t., dolenec, t. & tasev, g. (2006): new data concerning the major ore minerals and sulphosalts from the pb-zn zletovo mine, macedonia.– rmz-mater. geoenviron., 52/3, 535–548. serafimovski, t., dolenec, t. & tasev, g. (2006): new data concerning the major ore minerals and sulphosalts from the pb-zn zletovo mine, macedonia.– rmz-mater. geoenviron., 52/3, 535–548. serafimovski, t., dovrovolskaya, m.g., alexandrov, m. & stankovski, r. (1997): new data on the genesis of some pb-zn deposits in the serbomacedionian massif in the territory of the republic of macedonia.– in: symposium-annual meeting, dojran, 69–76. serafimovski, t., janković, s. & čifliganec, v. (1995): alpine metallogeny and plate tectonics in the sw flank of the carpatho-balkanides.– geologica macedonica, 9/1, 3–14. serafimovski, t., jelenkovic, r., tasev, g. & lazarov, p. (2003): mineral deposits related to tertiary magmatism in the southern part of the balkan peninsula.– geologica macedonica, 17, 19–23. serafimovski, t., tomson, i. n. & kocneva, n. t. (1997): alpine orogenic structures and metallogeny in the serbo-macedonian massif and the vardar zone of the territory of macedonia.– in: symposium-annual meeting, proceeding, dojran, 113–117. serafimovski, t., volkov, v.a., serafimovski, d., tasev, g., ivanovski, i. & murashov, y.k. (2017): plavica epithermal au-ag-cu deposit in eastern macedonia: geology and 3d model of valuable component distribution in ore.– geol. ore depos., 59, 296–304. simovski, a. (2020): statistical yearbook of the republic of north macedonia 2020.– state statistical office of the republic of north macedonia, skopje, 686 p. šoster, a., zavašnik, j., o’sullivan, p., herlec, u., potočnik krajnc, b., palinkaš, l., zupančič, n. & dolenec, m. (2020): geochemistry of bashibos-bajrambos metasedimentary unit, serbo-macedonian massif, north macedonia: implications for age, provenance and tectonic setting.– geochemistry, 80, 125664. doi: 10.1016/j.chemer.2020.125664 stankovski, r. (1997): morfostrukturno-strukturni i genetsko paragenetski karakteristiki na naogalisteto toranica [morpho-structural, genetic and paragenetic features of the tornica deposit – in macedonian].– master thesis , faculty of mining and geology, stip, 114 p. stojanov, r. (1980). vulkanskata kupa plavica polimetalnite mineralizacii i okolurudnite promeni vo nea [volcanic cone plavica and polymetallic alterations around it – in macedonian].– in: symposia rock alterations and minerals: 100 years of geological school and science in serbia, belgrade. stojanov, r., hadži-petrusev, b. & aleksandrov, m. (1995): dacitic rhyolitic volcanic products at bukovic-kadijca (pehčevo district) and the related porphyry copper mineralization.– geol. balk., 25-5/6, 83–90. strmić palinkaš, s, perkovic, i, čobič, a, jurkovic, i, tasev, g, serafimovski, t. & spangenberg, j. (2022): evolution of ore-forming fluids in a post-collisional porphyry cu-au system:a case study from the bucim deposit, republic of north macedonia.– ore geology reviews, 146, 1–20. doi: 10.1016/j.oregeorev.2022.104913 strmić palinkaš, s., peltekovski, z., tasev, g., serafimovski, t., šmajgl, d., rajic, k., spangenberg, е. ј., neufeld, k. & palinkaš, l. (2018): the role of magmatic and hydrothermal fluids in the formation of the sasa pb-zn-ag skarn deposit, republic of macedonia.– geosciences, 8/444, 1–28. doi: 10.3390/geosciences8120444 strmić palinkaš, s., tasev, g., serafimovski, t., palinkaš, l., šmajgl, d. & peltekovski, z. (2013): ore-fluid evolution at the sasa pb-zn skarn deposit, republic of macedonia.– in: 2013 ausimm new zealand branch annual conference proceedings. nelson, 487–494. tasev, g. & serafimovski, t. (2012): fluid inclusions study in the quartz from the zletovo mine.– in: jovanovski, m. & boev, b. (eds.): second congress of geologists of the republic of macedonia, proceedings book (special issue of geologica macedonica, № 3). macedonian geological society, 83–90. tasev, g. (2003): polimetalnite mineralizacii povrzani so tercierniot magmatizam vo republika makedonija [the polymetallic mineralizations related with tertiary magmatism in the republic of macedonia – in macedonian].– masters thesis, faculty of mining and geology, university “sts. cyril and methodius”, stip, 176 p. tasev, g. (2010): metalogenija na polimetaličniot rudonosen system bukovik-kadiica [metallogeny of the polymetallic ore bearing system bukovik-kadiica – in macedonian].– phd, university “goce delcev”, faculty of mining, geology and polytechnics, stip, 207 p. tasev, g., serafimovski, d. & serafimovski, t. (2018): evolution of oreforming fluids in the bukovik-kadiica porphyry cu deposit, republic of macedonia.– geologica croatica, 71/1, 1–18. doi: 10.4154/gc.2018.01 tasev, g., serafimovski, t & lazarov, p. (2005): new k-ar, 87sr/86sr, ree, and xrf data for tertiary volcanic rocks in the sasa-toranica ore district, macedonia.– in: mao, j. & bierlein, f.p. (eds.): mineral deposit research: meeting the global challenge: 8th sga biennial meeting, beijing, 837–840. tasev, g., serafimovski, t., dolenec, m. & rogan šmuc, n. (2019): contribution to understanding of ore fluids in the zletovo mine based on fluid inclusion data.– materials and geoenvironment, 66/2, 75–86. doi: 10.2478/ rmzmag-2019-0008 tomson, i.n., serafimovski, t. & kochneva, n.t. (1998): cenozoic metallogeny of eastern macedonia.– geol. ore dep., 40/4, 195–204. tudzarov, n. & serafimovski, t. (1994): general model for the formation of the borov dol porphiry copper deposit (macedonia).– annual of the mine and geology university sofia, 40/1, 125–137. tudzarov, n. & serafimovski, t. (1995): geotectonic setting and metallogenetic features of the borov dol porphyry copper deposit.– geologica macedonica, 9/1, 89–96. tudzarov, n. (1993): metalogenija na naogjališteto na bakar borov dol [metallogeny of the borov dol copper deposit – in macedonian].– phd thesis, faculty of mining and geology, stip, 195 p. tufar, w. & strucal, i. (1984): the sasa lead-zinc deposit (macedonia/yugoslavia) and its position in the serbian-macedonian ore province.– in: wauschkuhn, a., kluth, c. & zimmermann, r.a. (eds.): syngenesis and epigenesis in the formation of mineral deposits. springer, berlin, heidelberg, 412–421. doi: 10.1007/978-3-642-70074-3_37 volkov, a., serafimovski, t. & stefanova, v. (2010): formation mechanism of dwarfish cu-au porphyry deposits of macedonia.– dokl. earth sci., 431/5, 649–655. volkov, a., serafimovski, t., galyamov, a. & tasev, g. (2019): geophysic model of the earth’s crust and geodynamic position of lead-zinc deposits of the republic of north macedonia and neighboring countries.– geologica macedonica, 33/2, 89–98. g eo lo gi a c ro at ic a geologia croatica 75/3362 ap pe nd ix 1 ta bl e 1: s el ec tio n cr ite ria p ar am et er s g eo lo gi ca l c rit er ia se le ct io n cr ite ria 2 (a cc or di ng to w or d ri sk r ep or t) pa ra m et er s ( de fin ed by in ve st r m co ns or tiu m ) ra n k (d efi ne d by in ve st r m c on so rt iu m ) a b c g eo lo gi ca l c rit er ia le ve l o f c ur re nt ge ol og ic al kn ow le dg eda ta qu al ity th e ge ol og ic al c ha ra ct er is tic s o f t he tr ea te d po ly m et al lic d ep os its ar e fu lly a va ila bl e th ro ug h offi ci al p ub lic at io ns (e xp er t a nd sc ie nt ifi c pa pe rs , p er io di c re po rt s, fu nd d oc um en ta tio n of th e co m pa ni es th at h av e co nc es si on s f or e xp lo ita tio n or d et ai le d ge ol og ic al re se ar ch , g eo lo gi ca l e la bo ra te s f or c al cu la tio n an d re -c at eg or iz at io n of g eo lo gi ca l o re re se rv es , c on tin uo us p ro je ct s fo r d et ai le d ge ol og ic al a nd a dd iti on al e xp lo ra tio n of th e de po si ts , as w el l a s t he a va ila bi lit y of q ua lit at iv e an d qu an tit at iv e ch ar ac te ris tic s o f t he u se fu l m in er al c om po ne nt s i n th e de po si t). a ll ge ol og ic al in fo rm at io n on tr ea te d po ly m et al lic d ep os its is pu bl ic a nd a cc es si bl e an d ve ry w el l s tr uc tu re d an d cl as si fie d. h ig h le ve l o f a va ila bi lit y of g eo lo gi ca l d at a an d da ta re la te d to m aj or o re a nd a ss oc ia te d m et al s f or a ct iv e po ly m et al lic m in es o f: co pp er , l ea d an d zi nc . g eo lo gi ca l da ta a va ila bl e fro m p ro fe ss io na l a nd sc ie nt ifi c pa pe rs a nd sc ie nt ifi c pu bl ic at io ns a nd o pe ra tio na l d at a av ai la bl e fro m ge ol og ic al re po rt s t ha t a re p re pa re d ev er y 5 ye ar s. a nn ua l m et al p ro du ct io n re po rt s a re a ls o a go od so ur ce o f re le va nt in fo rm at io n. c op pe r d ep os its (p la vi ca , k ad iic a, ilo vi ca ) t ha t a re in th e st ag e of d et ai le d ex pl or at io n, b ut ar e no t a ct iv e ha ve g oo d qu al ity in fo rm at io n, a t t he le ve l of sc ie nt ifi c pu bl ic at io ns a nd re po rt s, bu t n ot a t t he le ve l of p er io di c re po rt s a nd o ffi ci al st at e da ta . in re ga rd s o f t he p ol ym et al lic d ep os its th at a re in a ct iv e ex pl oi ta tio n (b uc hi m , bo ro v d ol , s as a, to ra ni ca , z le to vo ) o nl y ce rt ai n pa rt s h av e th e ch ar ac te r o f un ex pl or ed p ot en tia l a re a (a ni sh te in th e ar ea o f t or an ic a, c rn v rv -k os he vo in th e ar ea o f b uc hi m , p et ro va r ek a in th e ar ea o f s as a, b liz an ci in th e ar ea o f zl et ov o) a nd th er e th e in fo rm at io n is m os tly o ld , m ai nl y fu nd so ur ce s a nd o ld re po rt s f or p ro sp ec tiv e an d in so m e pl ac es d et ai le d ge ol og ic al e xp lo ra tio n w ith dr ill in g, b ut w ith ou t u pd at in g th e da ta , a nd th e po te nt ia l i s g iv en b as ed o n si m ila r c rit er ia fr om m ai n si te s, on ly . i n th e po ly m et al lic , m ai nl y co pp er d ep os its su ch a re k ad iic a an d ilo vi ca , w hi ch a re st ill a t t he le ve l o f d et ai le d ex pl or at io n, th e in fo rm at io n ab ou t t he n ew n ea rb y po te nt ia l a re as is b as ed o n m od er n ge op hy si ca l r es ea rc h (te llu r g eo ph ys ic s) o r o n th e ba si s o f s ci en tifi c as se ss m en t of th e po te nt ia l o f t he lo ca lit yar ea . le ve l o f c ur re nt ge ol og ic al kn ow le dg equ an tit y le ad -z in c: l ev el a , m or e th an 3 .0 00 .0 00 t of re se rv es (a +b +c ca te go ry ) a nd e xp er t j ud ge m en t. co pp er : l ev el a d at a qu al ity , m or e th an 1 0. 00 0. 00 0 t o f r es er ve s ( a +b +c c at eg or y) . le ad -z in c: l ev el b , l es s t ha n 2. 00 0. 00 0 t o f r es er ve s (a +b +c c at eg or y) a nd e xp er t j ud ge m en t. co pp er : l ev el a da ta q ua lit y, le ss th an 1 0. 00 0. 00 0 t o f r es er ve s ( a +b +c ca te go ry ). le ad -z in c: a ny le ve l o f d at a qu al ity , i na cc es si bl e do cu m en ta tio n, e xp er t ju dg em en tsh or t e xp la na tio ns b as ed o n ar ea g eo lo gi ca l c ha ra ct er is tic s a nd hi st or ic al d at a. l ev el c o f d at a qu al ity w ith in ac ce ss ib le re se rv es d oc um en ta tio n co ns id er in g ex pe rt ju dg em en t.. ta bl e 2: s el ec tio n cr ite ria p ar am et er s s oc ia l l ic en ci ng , e nv iro nm en ta l m an ag em en t, pr oj ec t p er m itt in g, s ki lls a va ila bi lit y se le ct io n cr ite ria 2 (a cc or di ng to w or d ri sk r ep or t) pa ra m et er s ( de fin ed b y in ve st rm co ns or tiu m ) a b c so ci al li ce nc in g ac ce pt an ce b y lo ca l co m m un ity ex ce lle nt , l oc al c om m un ity is a w ar e of n ee d fo r e co no m ic al pr os pe rit y th at in du st ry b rin gs a lo ng , l oc al m in es o pe ra te w ith ou t c on fli ct , s up po rt ed b y lo ca l c om m un ity , l oc at io n of th e de po si t i s w ith in p oo r r ur al a re a in th e vi ci ni ty o f u rb an ar ea su ffi ci en t, lo ca l c om m un ity is a w ar e of n ee d fo r e co no m ic al pr os pe rit y th at in du st ry b rin gs a lo ng , h ow ev er se ve ra l in ci de nt s h av e be en re ce nt ly re po rt ed fr om lo ca l m in es op er at e, lo ca l c om m un ity is p ar tly su pp or tiv e bu t w or rie d fro m th e as pe ct s o f h ea lth a nd sa fe ty in su ffi ci en t o r p ro bl em at ic b as ed o n cu rr en t s ta te o f m in in g ac tiv iti es ; l oc al c om m un ity d oe s n ot a cc ep t i nd us tr y du e to fo cu s o n ot he r a re a (a gr ic ul tu re , t ou ris m ), us ua lly u rb an ar ea . l oc al m in es e xp er ie nc e va rio us p ro bl em s r el at ed to so ci al a cc ep ta nc e. en vi ro nm en ta l m an ag em en t le ga l r eq ui re m en ts : m as te r p la n, ei a , e nv iro ne m en ta l p er m it ex ce lle nt – e nv iro m en ta l p er m it is su ed g oo d – ei a p re pa re d in su ffi ci en t – e xp lo ita tio n fil ed n o t in cl ud ed in th e m as te r pl an pr oj ec t p er m itt in g le ga l r eq ui re m en ts : pr el im in ar y in ve st ig at io n w or k, m in in g pr oj ec t, co nc es si on p er m it ex ce lle nt – c on ce ss io n pe rm it is su ed g oo d – m in in g pr oj ec t a pp ro ve d in su ffi ci en t – n o re se ar ch a pp ro ve d an d/ or n o re se rv es de te rm in ed sk ill s av ai la bi lit y la bo ur c os t, sk ill s, ta sk fo rc e de fin ed in a w p2 s oc ia l a nd ec on om ic s d at a 45 un iq ue ra nk fo r b &h ; i n ge ne ra l 15 % h ig he r t ha n av er ag e sa la rie s g eologia c roatica serafimovski et al.: general features of some polymetallic ore deposits in the republic of north macedonia 363 ap pe nd ix 2 . b as e m et al s de po si ts in r ep ub lic n or th m ac ed on ia ta bl e 1. c upo ly m et al lic d ep os its in th e re pu bl ic n or th m ac ed on ia (d at a co m pl ie d af te r r ef er en ce s u se d in v er ifi ca tio n an d ev al ua tio n ph as e: č if li g a n ec (1 98 7) ; t a se v (2 01 0) ; g ra y et a l., (2 01 7) ; f o rv a rd e t a l., (2 01 7) ); se ra fi m o vs ki et a l., (2 01 7) . a re a d ep os it ke y to fi gu re 1 ag e sh ap e m in er al co m m od ity au (g /t ) cu (% ) re se rv es (t ) re so ur se s ( t) re se rv es + re so ur se s (a +b +c ₁+ c₂ +d ) d at a le ve l q ua nt ity pe rs pe ctiv ity so ci al lic en ci ng en vi ro nm en ta l m an ag em en t pr oj ec t pe rm ittin g (a +b +c ₁) (c ₂+ d ) kr at ov o zl et ov o pl av ic a 1 o lig oc en em io ce ne di ss em in at ed , s to ck w or k (p or ph yr y st yl e) ch al co py rit e en ar gi te -lu zo ni te cu -a uag 0. 28 1 0. 14 2 24 10 00 00 0 50 0, 00 0, 00 0. 0 74 1, 00 0, 00 0. 0 a a b b c bu ch im d am ja n bo ro v d ol bu ch im (r em ai ni ng bu na rd zi k an d cu ka r 2 ea st o re b od ie s) 2 o lig oc en em io ce ne di ss em in at ed , s to ck w or k (p or ph yr y st yl e) ch al co py rit epy rit ecu ba ni te -b or ni te na tiv e au cu -a uag 0. 12 80. 12 9 0. 18 60. 19 4 23 49 00 00 12 ,2 32 ,0 00 .0 35 ,7 22 ,0 00 .0 a a + a a a bo ro v d ol 3 o lig oc en em io ce ne di ss em in at ed , s to ck w or k (p or ph yr y st yl e) cu -a u 0. 12 80. 16 7 0. 22 80. 25 6 63 84 50 00 18 ,4 69 ,0 00 .0 82 ,3 14 ,0 00 .0 a a + a a a o gr az de n ilo vi ca 4 o lig oc en e po rp hy ry c uau st oc kw or k ch al co py rit epy rit ech al co ci te -c ov el lit ebo rn ite cu -a u 0. 27 -0 .2 8 0. 18 40. 18 9 45 87 61 68 0 30 0, 00 0, 00 0. 0 75 8, 76 1, 68 0. 0 a a c b c pe hc ev o ka di ic a ka di ic a 5 o lig oc en em io ce ne di ss em in at ed , s to ck w or k (p or ph yr y st yl e) , m ai n m in er al be ar in g m in er al iz at io n se co nd ar y su lfi de e nr ic hm en t ch al co ci te -c ov el lit epy rit ech al co py rit e cu 0. 21 36 0. 21 81 69 31 31 34 32 ,0 00 ,0 00 .0 10 1, 31 3, 13 4. 0 a a c b c ta bl e 2: le ad a nd zi nc d ep os its in r ep ub lic n or th m ac ed on ia (d at a co m pl ie d af te r r ef er en ce s u se d in v er ifi ca tio n an d ev al ua tio n ph as e: s er af im o vs ki & a le ks an d ro v (1 99 5) ; s tr m ić -p al in ka š et a l., (2 01 3) ; s tr m ić -p al in ka š et a l., (2 01 8) ) a re a d ep os it ke y to fi gu re 1 ag e sh ap e m in er al co m m od ity ag (g /t ) pb +z n (% ) re se rv es (t ) re so ur se s ( t) re se rv es + re so ur se s (a +b +c ₁+ c₂ +d ) d at a le ve l q ua nt ity pe rs pe ct iv ity so ci al lic en ci ng en vi ro nm en ta l m an ag em en t pr oj ec t pe rm itt in g (a +b +c ₁) (c ₂+ d ) sa sa to ra ni ca sa sa 8 o lig oc en em io ce ne irr eg ul ar , v ei n g al en asp ha le rit e pb -z nag 22 7. 58. 39 18 93 77 97 77 30 00 00 96 23 77 97 a a + a a a to ra ni ca 7 o lig oc en em io ce ne irr eg ul ar , b an ds , la ye rs , l en se s g al en asp ha le rit e pb -z nag 20 6. 33 -7 .4 0 49 59 10 1 76 40 89 9 12 60 00 00 a a + a a a kr at ov o zl et ov o zl et ov o 6 o lig oc en em io ce ne irr eg ul ar , v ei n, im pr eg na tio ns a nd st oc kw or k g al en asp ha le rit e pb -z nag 42 7. 95 -8 .0 1 69 58 70 8 17 70 91 9 87 29 62 7 a a + a a a g eo lo gi a c ro at ic a geologia croatica 75/3364 2021 | 74/2 | 121–126 | 4 figs. | 2 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the ichnogenus cardioichnus smith & crimes, 1983 embraces heart-shaped structures interpreted as a resting trace (cubichnia), produced by deposit-feeding, spatangoid irregular echinoids (known as heart urchins or potatoes) (smith & crimes, 1983; gibert & goldring, 2008). it is common in deepand shallow -marine deposits throughout the meso-cenozoic, from the kimmeridgian (bouchemla et al., 2020) to the pleistocene (mayoral et al., 2013; caruso & monaco, 2015). this trace fossil is preserved as a convex or concave form, ovoid or subquadrate in shape, in positive hyporelief or negative epirelief on sandstone beds, and formed by two symmetrical broad lateral lobes connected at the depressed v-shaped region (smith & crimes, 1983; gibert & martinell, 1995; kappus & lucas, 2019). five ichnospecies of cardioichnus are distinguished, including c. planus smith & crimes, 1983, the type ichnospecies; c. ovalis smith & crimes, 1983; c. foradadensis plaziat & mahmoudi, 1988; c. reniformis mayoral & muñiz, 2001 and c. biloba kappus & lucas, 2019. furthermore, this ichnogenus is found in association with locomotion traces, and it may co-occur with scolicia (mayoral & muñiz, 2001; uchman, 2007a), and bichordites (bernardi et al., 2010; mayoral et al., 2013; kappus & lucas, 2019). here, the ichnospecies c. planus is recorded for the first time from algeria and in the african continent. the interpretation of abundant c. planus from the lower miocene tiaret marl formation in western algeria is presented and discussed. furthermore, the spatangoid echinoid echinocardium nummuliticum péron & gauthier, 1885 has been proposed as the probable producer of the studied c. planus specimens. finally, a stratigraphic, palaeogeographic and palaeoenvironmental review of cardioichnus and its ichnospecies is presented. 2. geological setting and locality in the northwesternmost part of algeria, the lower chelif (e.g., naimi & cherif, 2021a; naimi et al., 2020), tafna (e.g., naimi the trace fossil cardioichnus planus from the lower miocene of algeria: the first record from africa and a probable endemic tracemaker mohammed nadir naimi1, amine cherif1,* and mourad belaid2 1 université de kasdi merbah, département des sciences de la terre et de l'univers, fherstu, ghardaïa road, ouargla, 30000, algeria; (*corresponding author: mohammednadirnaimi@gmail.com (mohammed nadir naimi); acherif11@gmail.com (amine cherif)) 2 université de kasdi merbah, laboratoire des réservoirs souterrains, pétroliers, gaziers et aquifères, ghardaïa road, ouargla, 30000, algeria; (mouradgeo14@gmail.com) doi: 10.4154/gc.2021.09 abstract abundant cardioichnus planus smith & crimes, 1983 have been reported for the first time from africa. they occur in lower miocene deep-marine deposits near tiaret in northwestern algeria. morphological features of the trace, coupled with the spatial interrelationships between cardioichnus and the echinoids documented in this area, provide evidence that the endemic spatangoid echinocardium nummuliticum péron & gauthier, 1885 represents the tracemaker of the studied c. planus. cardioichnus is known from the upper jurassic to the pleistocene and it has a wide geographic and environmental distribution. et al., 2021), the tiaret (cherif et al., 2021) neogene basins are located. they belong to the tell atlas (naimi & cherif, 2021b). the studied material comes from the tiaret marl formation (cherif et al., 2021) of sidi ali mellal section in the tiaret basin (polvêche, 1960). the section is located some kilometeres to the northwest of the town of tiaret (fig. 1a–c). the lower miocene tiaret marl formation crops out widely in the tiaret area. it overlies visean rhyolites (polvêche, 1960), or jurassic marine deposits (cherif et al., 2015, 2018; halamski & cherif, 2017; belaid et al., 2020), and is overlain by the upper miocene tiaret sandstone formation (cherif et al., 2021). the tiaret marl formation has been attributed to the lower miocene on the basis of a foraminiferal assemblage including cibicides mexicanus, c. pseudoungerianus, globigerinoides sac­ culiferus irregularis, g. triloba, nonion pompilioides, orbulina universa, pullenia bulloides and uvigerina rustica (polvêche, 1960; cherif et al., 2021). in sidi ali mellal section, the tiaret marl formation overlies the tardi-hercynian rhyolites and it has been subdivided into two main units (cherif et al., 2021). ichnological and sedimentological studies allowed the attribution of this formation to a deep-sea fan system, dominated by graphoglyptid trace fossils which characterize the turbidite successions and the nereites ichnofacies (cherif et al., 2021). moreover, these trace fossils have been subdivided into three ichnoassemblages corresponding to the nereites, paleodictyon, ophiomorpha rudis ichnosubfacies. the trace fossil assemblage reported from this formation includes cardioichnus isp., cf. chondrites isp., cosmorhaphe isp., desmograpton isp., gordia isp., helminthorhaphe isp., helminthopsis isp., cf. megagrapton isp., nereites isp., ophiomorpha isp., o. annulata, o. rudis, pala­ eophycus isp., paleodictyon majus, p. maximum, p. minimum, p. miocenicum, p. strozzii, cf. planolites isp., p. montanus, scoli­ cia isp., s. prisca, s. vertebralis, tisoa siphonalis, tubulichnium cf. incertum, urohelminthoida appendiculata and zoophycos isp. in the sidi ali mellal section, the ichnoassemblage of the first unit contains the trace fossil cardioichnus (fig. 1d). article history: manuscript received november 17, 2020 revised manuscript accepted march 05, 2021 available online june 30, 2021 keywords: cardioichnus planus, resting trace, echinocardium nummuliticum, lower miocene, algeria g eo lo gi a c ro at ic a geologia croatica 74/2122 figure 1. a) location of orania (northern algeria) in the western mediterranean. b) the main structural domains of western algeria. c) geological map of the study area. table 1. length, width and l/w ratio of the studied 65 cardioichnus planus (in mm). sample length width l/w ratio sample length width l/w ratio car-sam-001 24 21 1.14 car-sam-034 23 19 1.21 car-sam-002 24 18 1.33 car-sam-035 28 22 1.27 car-sam-003 23 16 1.43 car-sam-036 26 20 1.3 car-sam-004 26 24 1.08 car-sam-037 32 24 1.33 car-sam-005 21 20 1.05 car-sam-038 27 24 1.12 car-sam-006 27 22 1.22 car-sam-039 25 22 1.13 car-sam-007 26 22 1.18 car-sam-040 27 24 1.12 car-sam-008 27 22 1.22 car-sam-041 26 23 1.13 car-sam-009 23 19 1.21 car-sam-042 33 25 1.32 car-sam-010 21 20 1.05 car-sam-043 24 21 1.14 car-sam-011 24 20 1.2 car-sam-044 37 25 1.48 car-sam-012 22 20 1.1 car-sam-045 25 19 1.31 car-sam-013 26 22 1.18 car-sam-046 32 24 1.33 car-sam-014 23 19 1.21 car-sam-047 26 22 1.18 car-sam-015 23 16 1.43 car-sam-048 32 26 1.23 car-sam-016 21 18 1.16 car-sam-049 26 21 1.23 car-sam-017 21 18 1.16 car-sam-050 22 18 1.22 car-sam-018 22 20 1.1 car-sam-051 24 19 1.26 car-sam-019 27 22 1.22 car-sam-052 25 23 1.08 car-sam-020 27 20 1.35 car-sam-053 25 18 1.38 car-sam-021 22 18 1.22 car-sam-054 21 18 1.16 car-sam-022 25 21 1.19 car-sam-055 30 26 1.15 car-sam-023 21 17 1.23 car-sam-056 27 21 1.28 car-sam-024 28 21 1.33 car-sam-057 29 23 1.26 car-sam-025 24 21 1.14 car-sam-058 33 25 1.32 car-sam-026 23 17 1.35 car-sam-059 30 21 1.42 car-sam-027 24 17 1.41 car-sam-060 22 21 1.04 car-sam-028 22 19 1.15 car-sam-061 31 25 1.24 car-sam-029 24 21 1.14 car-sam-062 25 23 1.08 car-sam-030 22 18 1.22 car-sam-063 30 22 1.36 car-sam-031 27 20 1.35 car-sam-064 24 19 1.26 car-sam-032 25 22 1.13 car-sam-065 26 21 1.23 car-sam-033 25 20 1.25 average 25.58 20.87 1.22 g eologia c roatica naimi et al.: the trace fossil cardioichnus planus from the lower miocene of algeria: the first record from africa and a probable endemic tracemaker 123 3. material and methods more than seventy specimens of c. planus have been observed and collected by the authors during several field trips in to the tiaret basin between 2019 and 2020. the studied collection (n = 65) is deposited at the laboratory of geology of sahara at kasdi merbah ouargla university (car-sam-001 to car-sam-065). these sixty-five specimens were selected because of their preservation. they were photographed both in the field and the laboratory. the measurements were taken in the laboratory (table 1). also, the ichnotaxonomic identification of c. planus is in accordance with smith & crimes (1983). 4. results 4.1. description cardioichnus planus is very abundant in the sidi ali mellal section. it is a hypichnion in the sandstone beds, and co-occurs with scolicia vertebralis (fig. 2). the studied traces (fig. 3a-f) are heart-shaped mounds. they are ovoid or subquadratic in outline, bilobate and bilaterally symmetrical. their two lateral lobes are generally rounded, curved, and merged at the central axial depressed v-shaped depression. some specimens show a well developed posterior impression with a sharp edge at the terminus, which extends from the v-shaped depression, and separates the two distinct lobes. the mounds are 20–37 mm long and 16–26 mm wide, with a length/width ratio of about 1.05–1.42. the mean length (n = 65) is 25.58 mm, whereas the mean width is 20.87 mm (table 1). 4.2. remarks the selected samples have been attributed to cardioichnus planus due to their dimensions (l= 20–37 mm; w= 16–26 mm), and the length/width ratio which are similar to that described by smith & crimes (1983) and brustur (2005). the ovoid to subquadratic form of the studied specimens, their preservation as a convex body and the presence of two curved lateral lobes merged at the median longitudinal v-shaped depression and posterior impression characterize c. planus (smith & crimes, 1983; uchman, 2007a), and confirm their determination as this ichnospecies. 5. discussion 5.1. probable local tracemakers of the algerian c. planus spatangoid echinoderms or heart urchins are known from the early jurassic (buatois & mángano, 2018). they are the producers of bichordites, cardioichnus and scolicia. bichordites and scolicia are attributed to the burrowing of spatangoids. scoli­ cia is the best known among these ichnogenera. its oldest occurrence is from the tithonian of bulgaria (tchoumatchenco & uchman, 2001). all cardioichnus ichnospecies are considered to be resting traces produced by spatangoid echinoids (smith & crimes, 1983; plaziat & mahmoudi, 1988; mayoral & muñiz, 2001; kappus & lucas, 2019). the determination of tracemaker is problematic. in the oligocene of trentino (northeastern italy), cardioichnus isp. and the associated bichordites have been attributed to eupatagus ornatus (bernardi et al., 2010). furthermore, bichordites recorded from the middle miocene of spain has been attributed to the grazing activity of spatangoid echinoids assigned to the genus maretia (gibert & goldring, 2008). recently, the spatangoid heteraster has been considered as the tracemaker of the ichnospecies c. biloba, described from the mid-cretaceous of new mexico in the united states of america (kappus & lucas, 2019). the studied outcrop belongs to the southern tellian border of the ouarsenis range which constitutes the northern edge of the tiaret miocene basin. the most important palaeontological infigure 2. the stratigraphic succession and vertical distribution of trace fossils of the lower miocene tiaret marls formation in the sidi ali mellal section. figure 3. cardioichnus planus from the lower miocene of the sidi ali mellal section. a) car-sam-043. b) car-sam-044. c) car-sam-063. d) car-sam-055. e) car-sam-056. f) car-sam-057 (scale: 1 cm). g eo lo gi a c ro at ic a geologia croatica 74/2124 vestigations which yielded a rich echinoid fauna in the southern border of the ouarsenis range have been carried out at the kef ighoud section, located 50 km to the ene of our study area. kef ighoud echinoid-rich deposits have been attributed to the eocene (pomel, 1885), the oligocene (dalloni, 1936; mattauer, 1958) and finally to the lower to middle miocene on the basis of their planktonic foraminifera (derkaoui, 2017). several spatangoid echinoids have been described from the lower-middle miocene of the kef ighoud section (cotteau et al., 1885; pomel, 1885). the most important ones are echino­ cardium dubium péron & gauthier, 1885; e. nummuliticum péron & gauthier (fig. 4), 1885; euspatangus cruciatus péron & gauthier, 1885; e. hangenmulleri péron & gauthier, 1885; e. subrostratus péron & gauthier, 1885; pericosmus nicaisei pomel, 1885; p. subœquipetalus pomel, 1885; sarsella mauritanica pomel, 1885; schizaster mac carthyi pomel, 1885; spatanus (pseudopatagus) cruciatus pomel, 1885 and tuberaster tuberculatus péron & gauthi er, 1885. some taxa such as s. mauritanica and t. tuberculatus have been placed into the spatangoid genus hemipatagus (kroh, 2007). this echinoid fauna is important due to its endemism, and has never been reported out of this area. probable producers of cardioichnus are proposed on the basis of the similarities in size and morphology between the spatangoids and cardioichnus (kappus & lucas, 2019). however, among the spatangoid assemblage of kef ighoud, three species have similar sizes to the studied cardioichnus specimens. they include echinocardium dubium (l= 26 mm; w= 25 mm), e. nummuliticum (l= 26 mm; w= 23 mm) and euspatangus hangen­ mulleri (l= 25; w= 25). according to the l/w ratio, the two echi­ nocardium species resemble cardioichnus planus. however, the morphology of echinocardium nummuliticum allows proposing it as the probable tracemaker (fig. 4). the size decreases near the posterior part of the test where a prominent rostrum is present. accordingly, the posterior impression at the terminus of the trace could be interpreted as the imprint of this rostrum. alternatively, the ambitus of this species is heart-shaped, whereas it is rounded in e. dubium. this confirms that c. planus most closely resembles e. nummuliticum in size and morphology. echinocardium species occur generally in shallower environments. pomel (1887) indicated that the attribution of e. nummuliticum to this genus by péron & gauthier is incorrect, and these specimens should be revised. however, it co-occurs with other sea urchins such as schizaster (pomel, 1885) figure 4. echinocardium nummuliticum péron & gautier (1885) holotype, mnhn.f.j01420. photography peter massicard, program recolnat (arn-11-inbs-0004). a) aboral view. b) oral view. c) posterior view. d) side view. e) anterior view (scale: 0.5 cm). table 2. stratigraphic and geographic record of the ichnogenus cardioichnus. age ichnotaxa country references upper jurassic cardioichnus isp. algeria bouchemla et al. (2020) lower cretaceous cardioichnus isp. spain monaco et al. (2005); giannetti et al. (2014) c. biloba united states of america kappus & lucas (2019, 2020) c. foradadensis united states of america kappus & lucas (2020) upper cretaceous c. planus poland smith & crimes (1983) c. planus spain smith & crimes (1983) c. planus italy uchman (2007a) cardioichnus isp. poland książkiewicz (1977); rajchel & uchman (2012) cardioichnus isp. iran bayet-goll et al. (2016) paleocene cardioichnus isp. italy uchman (2007b) eocene c. ovalis switzerland smith & crimes (1983) c. foradadensis spain plaziat & mahmoudi (1988) c. ovalis romania brustur (1996) c. cf. planus romania brustur (1996) cardioichnus isp. romania buatois et al. (2001) cardioichnus isp. argentina lópez-cabrera et al. (2008) cardioichnus isp. italy monaco et al. (2017) oligocene cardioichnus isp. italy bernardi et al. (2010) oligocene/miocene c. planus romania brustur (2005) cardioichnus isp. tunisia riahi et al. (2014) miocene cardioichnus isp. new zealand manley & lewis (1998) c. reniformis spain mayoral & muñiz (2001) c. planus spain mayoral & muñiz (2001) cardioichnus isp. spain mayoral & muñiz (2001) cardioichnus isp. spain gibert & robles (2005) cardioichnus isp. argentina lópez-cabrera et al. (2008) cardioichnus isp. algeria cherif et al. (2020) cardioichnus planus algeria this paper pliocene cardioichnus isp. spain gibert & martinell (1995) c. planus spain gibert & martinell (1999) pleistocene cardioichnus isp. cape verde mayoral et al. (2013) cardioichnus isp. italy caruso & monaco (2015) g eologia c roatica naimi et al.: the trace fossil cardioichnus planus from the lower miocene of algeria: the first record from africa and a probable endemic tracemaker 125 which could be found in deep basins (mckinney, 1986). also, echinoids of the echinocardium group are responsible for traces with one drain such as bichordites, which could be continuous with cardioichnus and produced by the same organism. bichordi­ tes occurs from shallow-marine settings (uchman & krenmayr, 1995; bernardi et al., 2010; caruso & monaco, 2015) to slope deposits in soft substrates (villegas-martín et al., 2014). 5.2. stratigraphy, palaeoenvironments and palaeogeography the oldest cardioichnus were observed in the kimmeridgian of northwestern algeria, near this study area (bouchemla et al., 2020) (table 2). it occurs in the lower to transitional offshore environment characterizing the archetypal cruziana ichnofacies. this area belongs to the south tethyan ocean. this constitutes the only record of this ichnogenus in the jurassic. in the lower cretaceous, cardioichnus occurred in similar environments to those of the upper jurassic of algeria. it has been reported in seve ral domains from spain (tethyan realm) (monaco et al., 2005; giannetti et al., 2014) to north america (kappus & lucas, 2019, 2020). cardioichnus is common in flysch deposits from as early as the upper cretaceous. it has been found in iran, italy, poland and spain (książkiewicz, 1977; smith & crimes, 1983; uchman, 2007a; rajchel & uchman, 2012; bayet-goll et al., 2016). the cenozoic records seem to be more numerous. this ichnogenus is known from the palaeocene siliciclastic flysch deposits of italy (uchman, 2007b). it had a larger distribution during the eocene, generally in the circum-tethyan region (smith & crimes, 1983; plaziat & mahmoudi, 1988; brustur, 1996; buatois et al., 2001; monaco et al., 2017) and south american (lópez-cabrera et al., 2008) deep-sea systems, within ichnoassemblages assigned to the zoophycos and nereites ichnofacies. cardioich­ nus also has been reported from the oligocene and the oligomiocene of the mediterranean tethys in shallow (bernardi et al., 2010) to deep-sea deposits (brustur, 2005; riahi et al., 2014). miocene records of cardioichnus are widespread, e.g., it occurs in new zealand (manley & lewis, 1998), argentina (lópez-cabrera et al., 2008), and the western mediterranean basin, especially in spain (mayoral & muñiz, 2001; gibert & robles, 2005) and algeria (cherif et al., 2021; this paper). miocene cardioichnus have been reported from infralittoral shelf sands to deep-sea deposits. in the pliocene, car­ dioichnus is known only in spain from sandy storm beds, typical of the cruziana ichnofacies (gibert & martinell, 1995, 1999). finally, the newest records of this trace fossil are from the pleistocene of the tropical eastern atlantic (cape verde), in a moderate to high-energy shallow marine environment, where it constitutes part of the proximal cruziana ichnosubfacies (mayoral et al., 2013), and from the shallow deposits of southern italy (caruso & monaco, 2015). 6. conclusions the studied samples allow the following conclusions to be drawn: abundant cardioichnus planus has been found for the first time in africa; the studied specimens are dated as being of the lower miocene age, and co-occur with scolicia vertebralis; the endemic spatangoid echinoderm echinocardium num­ muliticum péron & gauthier, 1885 represents the probable tracemaker of the studied c. planus. acknowledgment we thank the managing editor of geologia croatica t. fluksi and the reviewers a. uchman (jagiellonian university, poland) and o. vinn (university of tartu, estonia) for their useful comments that have contributed to improving the original manuscript. the authors thank j. falconnet (mnhn of paris, france), who permitted us the use of the e. nummnliticum holotype photography. references bayet-goll, a., monaco, p., jalili, f. & mahmudy-gharaie, m.-h. (2016): depositional environments and ichnology of upper cretaceous deep-marine deposits in the sistan suture zone, birjand, eastern iran.– cretaceous research, 60, 28–51. doi: 10.1016/j.cretres.2015.10.015 belaid, m., cherif, a., vinn, o. & naimi, m.n. (2020): first record of trace fossils from the oxfordian argiles rouges de kheneg formation (tiaret, northwestern algeria).– geologia croatica, 73/2, 85–94. doi: 10.4154/gc.2020.10 bernardi, m., boschele, s., ferretti, p. & avanzini, m. (2010): echinoid burrow bichordites monastiriensis from the oligocene of ne italy.– acta palaeontologica polonica, 55, 479–486. bouchemla, i., bendella, m., benyoucef, m., lagnaoui, a., ferré, b., scherzinger, a. & bel haouz, w. (2020): the upper jurassic faïdja formation (northwestern algeria): sedimentology, biostratigraphy and ichnology.– journal of african earth sciences, 169, 103874. brustur, t. (1996): the stages of the paleoichnological studies in romania.– geoeco-marina, 2, 205–216. brustur, t. (2005): the ichnogenus cardioichnus from the vineţişu formation (upper oligocene-lower miocene, romania).– proceedings of the romanian academy, series b, 2, 51–53. buatois, l.a., mángano, m.g. & sylvester, z. (2001): a diverse deep-marine ichnofauna from the eocene tarcau sandstone of the eastern carpathians, romania.– ichnos, 8, 23–62. doi: 10.1080/10420940109380172 buatois, l.a. & mángano, m.g. (2018): the other biodiversity record: innovations in animal-substrate interactions through geologic time.– gsa today, 28/10, 4–10. doi: 10.1130/gsatg371a.1 caruso, c. & monaco, p. (2015): bichordites monastiriensis ichnofabric from the pleistocene shallow-marine sandstones at le castella (crotone), ionian calabria, southern italy.– rivista italiana di paleontologia e stratigraphia, 121/3, 381–397. doi: 10.13130/2039-4942/6524 cherif, a., bert, d., benhamou, m. & benyoucef, m. (2015): la formation des argiles de saïda (jurassique supérieur) dans le domaine tlemcenien oriental (takhemaret, algérie): données biostratigraphiques, ichnologiques et sédimentologiques.– revue de paléobiologie, 34/2, 363–384. cherif, a., benyoucef, m., ferre, b. & benhamou, m. (2018): etude sédimentologique et ichnologique de la formation des argiles de saïda (jurassique supérieur) dans les monts de frenda (algérie nord-occidentale).– revue de paléobiologie, 37/1, 121–135. cherif, a., naimi, m.n. & belaid, m. (2021): deep-sea trace fossils and depositional model from the lower miocene tiaret marl formation (northwestern algeria).– journal of african earth sciences, 175, 104115. doi: 10.1016/j.ja frearsci.2021.104115 cotteau, g., peron, a. & gauthier, v. (1885): echinides fossiles de l’algérie: terrains tertiaires.– masson edition, paris, 273 p. dalloni, m. (1936): matériaux pour l’étude géologique du massif de l’ouarsenis.– bulletin du service de la carte géologique de l’algérie, 2, 1–41. derkaoui, s. (2017): etude paléontologique, ichnologique et sédimentologique de la série miocène inférieur/moyen de kef ighoud (ouarsenis oriental, algérie).– unpubl. msc thesis, university of oran 2, 65 p. giannetti, a., monaco, p., corbí, h. & soria, j.m. (2014): integrated taphonomy in an open-marine platform: the lower cretaceous of sierra helada (betic cordillera, se spain).– cretaceous research, 51, 274–284. doi: 10.1016/j.cretres.2014.07.001 gibert, j.m. de & martinell, j. (1995): sedimentary substrate and trace fossil assemblages in marine pliocene deposits in northeast spain.– geobios, 28/supp.1, 197–206. doi: 10.1016/s0016-6995(95)80166-9 gibert, j.m. de & martinell, j. (1999): proximal-distal variations of trace fossil assemblages in a pliocene ria, baix llobregat, northeastern spain.– revista de la sociedad geológica de españa, 12/2, 209–214. gibert, j.m. de & robles, j.m. (2005): firmground ichnofacies recording highmarine flooding events (langhian transgression, vallès-pendès basin, spain).– geologica acta, 3, 295–305. gibert, j.m. de & goldring, r. (2008): spatangoid-produced ichnofabrics (bateig limestone, miocene, spain) and the preservation of spatangoid trace fossils.– pag eo lo gi a c ro at ic a geologia croatica 74/2126 laeogeography, palaeoclimatology, palaeoecology, 270/3–4, 299–310. doi: 10.1016/j.palaeo.2008.01.031 halamski, a.t. & cherif, a. (2017): oxfordian brachiopods from the saïda and frenda mountains (tlemcenian domain, north-western algeria).– annales societatis geologorum poloniae, 87, 141–156. doi: 10.14241/asgp.2017.006 kappus, e.j. & lucas, s.g. (2019): a new ichnospecies of cardioichnus from the cretaceous (albian) of new mexico.– ichnos, 26, 127–133. kappus, e.j. & lucas, s.g. (2020): ichnology of the lower cretaceous (albian) mesilla valley formation, cerro de cristo rey, southeastern new mexico, usa.– new mexico geology, 42, 3–30. kroh, a. (2007): hemipatagus, a misinterpreted loveniid (echinodermata: echinoidea).–journal of systematic palaeontology, 5/2, 163–192. doi: 10.1017/ s1477201906002021 książkiewicz, m. (1977): trace fossils in the flysch of the polish carpathians.–palaeontologia polonica, 36, 1–208. lópez-cabrera, m.i., olivero, e.b., carmona, n.b. & ponce, j.j. (2008): cenozoic trace fossils of the cruziana, zoophycos and nereites ichnofacies from fuegian andes, argentina.– ameghiniana, 45/2, 377–392. mattauer, m. (1958): etude géologique de l’ouarsenis oriental (algérie).– bulletin du service géologique de l’algérie, 17, 1–534. manley, r. & lewis, d.e. (1998): ichnocoenoses of the mount messenger formation, a miocene submarine fan system, taranaki basin, new zealand.– new zealand journal of geology and geophysics, 41/1, 15–33. doi: 10.1080/00288306. 1998.9514787 mayoral, e. & muñiz, f. (2001): new ichnospecies of cardioichnus from the miocene of the guadalquivir basin, huelva, spain.– ichnos, 8/1, 69–76. doi: 10.1080/10420940109380174 mayoral, e., ledesma-vazquez, j., baarli, b.g., santos, a., romalho, r., cachão, m., da silva, c.m. & johnson, m.e. (2013): ichnology in oceanic islands: case studies from the cape verde archipelago.– palaeogeography, palaeoclimatology, palaeoecology, 381–382, 47–66. doi: 10.1016/j.palaeo.2013.04.014 mckinney, m.l. (1986): ecological causation of heterochrony: a test and implications for evolutionary theory.– paleobiology, 12/3, 282–289. doi: 10.1017/ s0094837300013786 monaco, p., giannetti, a., caracuel, j.e. & yébenes, a. (2005): lower cretaceous (albian) shell-armoured and associated echinoid trace fossils from the sácaras formation, serra gelada area, southeast spain.– lethaia, 38/4, 333–344. doi: 10.1080/00241160500355277 monaco, p., rodríguez-tovar, f. & uchman, a. (2017): the ichnocoenosis of the bottom nepheloid layer (bnl) deposits: a case study from the scaglia toscana formation (paleogene, central italy).– bollettino della società paleontologica italiana, 56/2, 243–251. doi: :10.4435/bspi.2017.13 naimi, m.n. & cherif, a. (2021a): ichnological analysis of the late miocene shallow marine diatomaceous deposits of the lower chelif basin (northwestern algeria): paleoenvironmental insights and comparison with deep diatomites.– journal of african earth sciences, 104239. naimi, m.n. & cherif, a. (2021b): inventory and assessment of significant scientific algerian geoheritage: case of remarkable geosites from orania (western algeria). – international journal of geoheritage and parks, 9, 13–29. naimi, m.n., mansour, b., cherif, a., chekkali, m.c., benkhedda, a. & belaid, m. (2020): lithostratigraphie et paléoenvironnements des dépôts messiniens de la terminaison nord-orientale des monts des ouled ali (bassin du bas chélif, algérie nord-occidentale).– revue de paléobiologie, 39, 467–483. naimi, m.n., vinn, o. & cherif, a. (2021): bioerosion in ostrea lamellosa shells from the messinian of the tafna basin (nw algeria).– carnets de géologie, 21/5, 127–135. plaziat, j.c. & mahmoudi, m. (1988): trace fossils attributed to burrowing echinoids: a revision including new ichnogenus and ichnospecies.– geobios, 21/2, 209–233. doi: 10.1016/s0016-6995(88)80019-6 polveche, j. (1960): contribution à l’étude géologique de l’ouarsenis oranais.– bulletin du service de la carte géologique de l’algérie, 24, 1–577. pomel, a. (1885): les échinides du kef ighoud.– matériaux pour la carte géologique de l’algérie, algiers, 31 p. pomel, a. (1887): echinodermes, fascicule 2.– paléontologie ou description des animaux fossiles de l’algérie, algiers, 344 p. rajchel, j. & uchman, a. (2012): ichnology of upper cretaceous deep-sea thickbedded flysch sandstones: lower istebna beds, silesian unit (outer carpathians, southern poland).– geologica carpathica, 63/2, 107–120. doi: 10.2478/v10096012-0009-3 riahi, s., uchman, a., stow, d., soussi, m. & ben ismail lattrache, k. (2014): deep-sea trace fossils of the oligocene-miocene numidian formation, northern tunisia.– palaeogeography, palaeoclimatology, palaeoecology, 414/15, 155–177. doi: 10.1016/j.palaeo.2014.08.010 smith, a.b. & crimes, t.p. (1983): trace fossils formed by heart urchins – a study of scolicia and related traces.– lethaia, 16, 79–92. doi: 10.1016/j.pa laeo.2014.08.010 tchoumatchenco, p. & uchman, a. (2001): the oldest deep-sea ophiomorpha and scolicia and associated trace fossils from the upper jurassic-lower cretaceous deep-water turbidite deposits of sw bulgaria.– palaeogeography, palaeoclimatology, palaeoecology, 169/1–2, 85–99. doi: 10.1016/s0031-0182(01)00218-8 uchman, a. & krenmayr, h.g. (1995): trace fossils from lower miocene (ottnangian) molasse deposits of upper austria.– paläontologische zeitschrift, 69/3, 503–524. doi: 10.1007/bf02987810 uchman, a. (2007a): deep-sea trace fossils from the mixed carbonate-siliciclastic flysch of the monte antola formation (late campanian–maastrichtian), north apennines, italy.– cretaceous research, 28/6, 980–1004. doi: 10.1016/j.cretres.2007.01.005 uchman, a. (2007b): trace fossils of the pagliaro formation (paleocene) in the north apennines, italy.– beringeria, 37, 217–237. villegas-martín, j., netto, r.g., lavina, e.l.c. & rojas-consuegra, r. (2014): ichnofabrics of the capdevila formation (early eocene) in the los palacios basin (western cuba): paleoenvironmental and paleoecological implications.– journal of south american earth sciences, 56, 214–227. doi: 10.1016/j. jsames.2014.09.006 www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2024 | 77/3 | 235–242 | 5 figs. | 1 supplement | 1. introduction karst caves are formed in carbonate rocks mainly due to a pro­ cess of rock removal by dissolution when water circulates un­ derground and interacts with the carbonates (e.g. ford & williams, 2007). this process leaves behind empty spaces with shapes and morphological features that are informative of the various parametres that guide the process of speleogene­ sis, namely the hydrology, chemistry and availability of rock fractures and discontinuities. other agents can additionally contribute to the formation of caves including erosion in mainly well­formed mature cave systems (e.g. farant & smart, 2011), breakdown when physical conditions are fa­ vourable for ceiling collapse (e.g. white & white, 2000; osborne, 2002), or condensation corrosion by water that condenses on the rock surface when it is colder than the air (e.g. dreybrodt et al., 2005; gabrovšek et al., 2010). a process-based classification of caves can be found in la­ zaridis (2022). all these various processes are amalga­ mated during speleogenesis and they shape the expansion of the cave space. they can act simultaneously or in successive phases of development with variations in their intensity. the resulting morphology of each agent is predictable and can be investigated in the karst cave environment. this is the key to identifying morphological features at various scales when understanding speleogenesis. large­scale features including the ground plan pattern are related to the speleogenetic phases, whereas features in the dimensions of passages or even smaller openings are relatively susceptible to phase changes and mainly reflect events of various cave modifications such as corrosion by invasive water, erosion, condensation corrosion, and collapse (e.g. lauritzen & lundberg, 2000). deciphering rock surface origins in a karst cave: insights from the rača cave, lastovo, croatia georgios lazaridis1,*, konstantinos p. trimmis2, ivan drnić3 and kristina brkić drnić4 1 aristotle university of thessaloniki, faculty of sciences, school of geology, 54124 thessaloniki, greece; (*corresponding author: geolaz@geo.auth.gr) 2 university of bristol, department of anthropology and archaeology, 43 woodland road, bs8 100 bristol, uk 3 archaeological museum, trg nikole zrinskog 19/1, 10000 zagreb, croatia 4 university of zadar, department of archaeology, ulica mihovila pavlinovića 1, 23000 zadar, croatia doi: 10.4154/gc.2024.13 abstract this paper outlines a comprehensive fieldwork methodology for discerning the origin of rock surfaces within a karst cave environment. this methodology is particularly utilized in a cave with breakdown morphology. using rača cave in lastovo, croatia as a case study, we explore geological and morphological features through advanced surface analysis. the approach involves meticulous measurement of rock discontinuities, joint patterns, and surface formations. cost-efficient and time-efficient data collection and processing during field-work were undertaken with fieldclino move and polycam applications on smartphones. visualization techniques were employed to elucidate the interplay between erosion, deposition, and speleogenetic processes. however, when it comes to studying these forms various factors obscure observations and interpretations. these are mainly depositional phases of clastic and chemical sediments that cover the floor and the upper part of the cave passages, respectively. to summarise, the following surfaces can be observed in caves and studied to understand their development: • dissolution surfaces of the carbonate rock due to flowing underground water • dissolution surfaces due to condensation corrosion that re­sculpt wall­rocks and speleothems • surfaces that correspond to bedding planes and rock fractures revealed after breakdown events • depositional features • erosional sensu lato surfaces that correspond to paragenesis (e.g. pasini, 2009). the complexity of these processes and their interaction can make the identification and discrimination of the various morphological features during fieldwork challenging and sometimes questionable. this was the case during fieldwork in the archaeological rača cave in croatia. the first impression when entering the cave is that it is formed due to collapse favoured by the intermediate dip­angle of the bedding planes. the goal of this research is to identify speleogenetic processes and to distinguish the cause­and­effect relationship of primary structural elements (bedding, faults) with the occurrence of different dissolution and depositional forms in the speleological object. to investigate, identify, and visualize specific surfaces we combined measurements of the orientation of a large number of structural elements, dissolution features, together with 3d scanning of the cave. article history: manuscript received: august 22, 2023 revised manuscript accepted: june 04, 2024 available online: october 02, 2024 keywords: cave survey, 3d scanning, structural analysis, adriatic sea, dinarides, speleogenesis, dissolution, breakdown g eo lo gi a c ro at ic a 236 geologia croatica 77/3 2. geological setting lastovo island is located in the vicinity of a notable seismi­ cally active area (e.g. garašić, 2021). along with 45 other smaller islands, it forms the lastovo archipelago, where up­ per jurassic to mid-cretaceous limestones were deposited on the adriatic carbonate platform (vlahović et al., 2002). the karst landform of the area was formed after the alpine orogeny (vlahović et al., 2005; korbar, 2009) that shaped the area, due to the exogenous processes. most of the continental karst caves in croatia are of vertical development (garašić, 1991), whereas most of the submerged caves are horizontally developed (surić et al., 2010). late jurassic mudstone and wackestone are the oldest rocks that crop out on the island. a fault running along the northern shoreline of the island distinguishes the younger carbonate rocks from the older succession (sokač et al., 2014). the island's landscape features the presence of karst depressions and formations such as poljes and karren. 3. cave description rača cave is located on the island of lastovo at 140 m asl (n42˚ 44´ 05´́ , e016˚ 54´ 38´́ wgs84; fig. 1a), and is the largest recorded cave on the island to date (marjanac, 1956; drnić & brkić drnić, 2023). the cave's developmental orientation aligns along a w­e axis, and its entrance is a result of breakdown processes (refer to fig. 1b). the initial chamber stands as the largest, while subsequent chambers are demarcat ed by the presence of speleothem depositions, which take shape as expansive columns and flowstone. small windows formed amidst the speleothems establish inter connections between different areas of the chambers. notably, the vertical span of the cave measures ~17 metres. enclosing the cave's ground plan, the minimum encompassing rectangle spans dimensions of ~73 metres by ~20 metres, as extracted from the 3d scan. within the cave, the floor is covered with clastic sediments, forming a cone of debris near the entrance. as one ventures towards the cave's depths, the sediment-laden floor assumes a relatively horizontal disposition. subsequent chambers exhibit progressively lower elevations above sea level. the ceiling primarily consists of flat inclined surfaces. dominating the central expanse of the cave, substantial speleothems such as stalagmites and columns partition the various chambers. these formations exhibit signs of breakage, characterized by an array of cracks, some of which are filled with calcite deposits. in the entrance zone, it can be observed and should be noted, that these formations display evidence of corrosion attributed to condensation processes. however, in the cave's more profound recesses, the speleothems appear unaffected by this corrosive phenomenon, either covered by calcite encru­ stations stemming from stagnant water or otherwise not subjected to this specific process. 4. methodology to identify and visualize dissolution surfaces within the cave, the approach involved creating a comprehensive dataset of rock discontinuities in the limestone above the cave. this dataset encompasses measurements of dip direction and dip angle for both bedding planes and rock fractures, such as joints. these measurements were meticulously acquired using the fieldmove clino application by midland valley (petroleum engineering and structural geology software), after checking the calibration of the smartphone’s sensors (magnetometer/ gyroscope/accelerometer; see software’s manual at www. petex.com). the collected data were associated with the "limestone" unit utilized in our analysis. subsequently, random measurements were conducted within the cave, correlating with a designated unit termed "cave". notably, these mea sure­ ments were taken on exposed surfaces devoid of speleothem coverings and were distributed throughout the cave's extent. the next phase involved projecting and comparing the two datasets on a unified stereo net diagram and scatter diagram. the scatter diagram served to establish the 99% confidence interval ellipses for bedding planes and the pair of joint sets defined within the limestone unit. plot and confidence intervals are drawn in past software (hammer et al., 2001). for classification purposes, any measurements from the "cave" figure 1. location and three-dimensional space of the rača cave: a – croatia map with lastovo island and rača cave depicted. b – ground-plan of the cave. g eologia c roatica 237lazaridis et al.: deciphering rock surface origins in a karst cave: insights from the rača cave, lastovo, croatia dataset that overlapped with the range of the "limestone" dataset were categorized as breakdown surfaces. conversely, measurements outside this range were indicative of dissolution processes. to comprehensively document these features, we utilized photo documentation and 3d modelling techniques employing the 3d scanner application and lidar sensors integrated into the iphone 14 pro. with respect to the mapping grades of the international union of speleology (uis) as given in häuselmann (2011), the survey has the possibility to provide scans that are reliable to a single centimetre (zaczekpeplinska & kowalska, 2022) and although variable, they easily fit grade 5 and, in many cases, can reach the prerequisites for grade 6. map detail grade corresponds to 4, which is the maximum detail, and regarding qualifications the suffixes b to f fit to this method (häuselmann, 2011). in terms of qualitative assessment, various criteria were employed to distinguish different sections of side walls and ceilings see supplement: • condensation corrosion was discerned through observed cuts in speleothems, which formed cupolas or similar pockets • breakdown surfaces were typified by a flat ceiling following bedding planes, angular connections between planar surfaces, and abrupt terminations of adjacent smooth dissolution pockets • surfaces not aligning with the aforementioned criteria commonly pertained to dissolution stages of speleogenesis and could exhibit attributes including cupolas, scallops, flutes, pendants, and more • furthermore, surfaces linked to erosion sensu lato, referred to as paragenesis, were discerned by their distinctive dissolution forms. these features were intricately connected with specific cave passages and micro-scale morphologies. notable examples encompassed paragenetic pendants, meandering paragenetic canyons, lateral notches with half-tube configurations, and scallops (farrant & smart, 2011; lauritzen & lauritsen, 1995). 5. results and discussion caves represent underground voids that emerge through distinct geological and biological processes (refer to lazaridis, 2022, for a formal definition). these spaces are delineated by boundaries (curl, 1964), referred to as surfaces throughout the text, and are intimately linked to the direct action of speleogenetic processes. examining these surfaces facilitates the identification of various events and agents responsible for their creation, encompassing both erosional and depositional manifestations. although this methodology primarily concentrates on surfaces with erosional characteristics, it's important to recognize that both types of surfaces offer crucial insights into comprehending cave evolution. we meticulously measured rock discontinuities (n=52) of thick-bedded limestone on the surface above the cave and at a distance of about 50 metres from the cave entrance (fig. 2). in this area, where the limestone crops out, we recognized bedding planes, exhibiting an average dip direction and angle of 12°/14° and two groups of joints: j1: 184°/50° and j2: 111°/72°. within the cave's interior, we conducted measurements on arbitrary rock surfaces (n=139), deliberately avoiding those concealed by speleothems. these measurements were plotted on the stereonet diagram illustrated in fig. 3a. while an overlap between the two datasets is evident, it is noteworthy that a substantial number of cave surfaces do not align with the orientations of rock discontinuities. in pursuit of deeper insight, we further projected all data onto the scatter diagram shown in figure 3c. correlating strike with dip angle. as anticipated, the two datasets display partial overlap. ellipses on this diagram represent the 99% confidence interval (the percentage of the population that falls in these ellipses), underscoring that surfaces falling within these ellipses cannot be rejected as belonging to the rock's discontinuities, at a level of significance α=0.01. the shared domain between the "cave" dataset and the "limestone" dataset signifies surfaces that reasonably align with bedding planes figure 2. a – location of the entrance of rača cave and the area where “limestone” dataset of rock discontinuities was measured. b – characteristic appearance of the limestone in the cave surroundings. g eo lo gi a c ro at ic a 238 geologia croatica 77/3 figure 4. the first and largest chamber of rača cave, with ceiling surfaces dominated by breakdown surfaces along bedding planes and joints of the limestone. figure 3. analysis of “limestone” and “cave” datasets from rača cave. a – rock discontinuities and random rock surfaces of the cave boundaries are plotted together: bedding planes (b.p.), and two joint sets j1 and j2 are indicated. b – random rock surfaces that correspond to dissolution surfaces; data for which the hypothesis to belong to limestone discontinuities cannot be rejected have been excluded (see fig. 5 and text). c – scatter diagram of the “limestone” and “cave” datasets analysed from rača cave. coloured dots and ellipses of 99% confidence intervals are plotted for the “limestone” dataset that consists of the group of bedding planes (b.p.; green dots) and joint sets j1 (blue dots) and j2 (red dots). black dots represent the “cave” dataset of random rock surfaces that define the cave boundaries. d – sw view of the cave, where the ceiling defined by bedding planes (b.p.) and the walls defined by joints (j1) can be observed (see text). g eologia c roatica 239lazaridis et al.: deciphering rock surface origins in a karst cave: insights from the rača cave, lastovo, croatia and joints originating from breakdown events. qualitatively, these surfaces significantly contribute to the definition of the cave's contours, a characteristic demonstrated in the threedimensional cave model showcased in figure 3d. and in figure 4. of the first chamber. considering both the quantitative findings and qualitative observations, the overall morphology of rača cave distinctly exhibits characteristics associated with collapse formations (fig. 4). within diverse insular environments, such as mallorca, a range of cave classifications are discernible, encompassing "va­ dose shafts," "vadose located caves," "phreatic caves," and "in­ sular caves" (as described by ginés, 1995). notably, break­ down caves are prevalent within the category of "vadose located caves." these cases comprise segments, where the original cave boundaries undergo transformation due to the dislodgment of blocks from the ceiling or walls. this phenomenon, coupled with the deposition of speleothems, often muddles observations and complicates speleogenetic interpretations. it is worth not­ ing that numerous other cave types, such as structurally con­ trolled caves, conduit­caves, network caves, and mechanical shafts, as discussed by ginés (1995), commonly exhibit sec­ tions influenced by breakdown-related alterations. rača cave, while predominantly showcasing breakdown characteristics, appears to offer indications of processes be­ yond mere breakdown. as delineated in figure 3c., several surfaces deviate from the 99% confidence interval designated for limestone discontinuities. this subset of the dataset is pro­ jected on the stereonet of figure 3b. and is indicative of dis­ solution surfaces, with the caveat that paragenetic features lack qualitative verification. these surfaces predominantly define the southern segments of the cave and manifest as relatively diminutive cupolas adorning the cave ceilings or resemble a long smooth and curved surface that extends along the long axis of the cave (fig. 5). speleothems formed within these regions exhibit signs of condensation corrosion (fig. 5a), signifying some degree of modification resulting from this process. such surfaces are delimited upwards to breakdown surfaces. old and younger breakdown events can be recognized by differences in the smoothness of the surfaces (fig. 5b), indicating that this process took place in multiple events. various methodologies that relate structural analysis, cave morphology, cave morphometry and hydrogeology have been introduced and applied on numerous caves and karst systems (e.g. plan et al., 2009; picini, 2011; jouves et al., 2017; szczygieł et al., 2022; dora et al., 2023) in order to in­ vestigate their speleogenesis. however, in the case of rača cave, these methods had limitations or cannot even be applied due to the extent of breakdown morphology. that means in every explored passage of the cave the dominant features are related to collapse. the origin of the very few dissolution fea­ tures that were identified is speculative. the general shape of the cave exhibits an e-w elongation, affected by the joint sets j1 and the bedding planes. according to studies on cave de­ velopment and active tectonics, (so­called cavitonics), cave passages tend to be developed perpendicular to the extensional component of the stress field (littva et al., 2015; shanov & kostov, 2015; lazaridis et al., 2024) and this con­ forms to the orientation of the nontectonic e­w structures in the broader area (marinčić, 1997). regarding the employed fieldwork techniques, it's important to highlight that the capability to gather and promptly visualize data significantly and instantly enhanced our comprehension of the diverse morphological surfaces within the cave. furthermore, the concurrent generation of 3d models (fig. 1b) facilitated the documentation of these characteristics, emerging as a comprehensive tool for cave site investigation. by enabling observations from multiple perspectives and presenting the cave as a cohesive entity, this approach transcended the practice of examining individual segments in isolation. figure 5. a – illustration of a dissolution surface at the lower part of the first chamber in rača cave and how it is associated with breakdown surfaces and corroded speleothems by condensation corrosion. b – the same spot observed from the northern part of the first chamber, where breakdown surfaces of two different events can be observed. g eo lo gi a c ro at ic a 240 geologia croatica 77/3 6. conclusions it's not uncommon for breakdown morphology to obscure the clear identification of features associated with the dissolution stages of speleogenesis. through our analysis, we have presented compelling evidence for the existence of additional processes within rača cave, a site predominantly characterized by breakdown formations. the manifestation of these processes becomes evident through the presence of dissolution surfaces, which exhibit a statistically significant distinction from the rock discontinuities. these distinctions are effectively visualized using scatter diagrams. by employing qualitative criteria, we have successfully identified condensation corrosion and particular original phreatic features. the selected tools not only proved to be time-efficient but also enabled engagement in real-time data visualization while perceiving the cave's morphology as a cohesive entity. in its entirety, our fieldwork analysis has provided a comprehensive understanding of various intricacies related to the surfaces that delineate the boundaries of the cave. moreover, this analysis has enabled us to perform statistical comparisons of datasets, thereby attributing a level of significance to our observations. acknowledgment we sincerely thank the anonymous reviewers for their constructive comments, which greatly contributed to the improvement of our paper. references curl, r.l. (1964): on the definition of a cave.– bulletin of national speleo­ logical society, 26, 1, 1−6. dora, d., lazaridis, g., vouvalidis, k., tokmakidis, k. & veni, g. (2023): morphometric analyses of greek caves: how mor­ phology predicts cave origin.– bulletin of the geological society of greece, 60/1, 14–26. doi: 10.12681/bgsg.34887 dreybrodt, w., gabrovšek, f. & perne, m. (2005): condensation corrosion: a theoretical approach.– acta carsol., 34/2, 317–347. doi: 10.3986/ac.v34i2.262 drnić, k.b. & drnić, i. (2023): an island in the heart of the adriatic sea – finds from the rača cave on the island of lastovo.– in: drnić, k.b., trimmis, p.k. & drnić, i. (eds): finds stories, addressing mobility through people and object biographies. archaeological museum in za­ greb, 17–30. farrant, a.r. & smart, p.l. (2011): role of sediment in speleogenesis; sedimentation and paragenesis.– geomorphology, 134, 79–93. doi: 10.1016/j.geomorph.2011.06.006 gabrovšek, f., dreybrodt, w. & perne, m. (2010): physics of con­ densation corrosion in caves.– in: carrasco, f., valsero, j.j.d. & lamoreaux, j.w. (eds.): advances in research in karst media. spring­ er, berlin, heidelberg, 491–496. doi: 10.1007/978-3-642-12486-0_75 garašić, m. (1991): morphological and hydrogeological classification of speleological structures (caves and pits) in the croatian karst area.– ge­ ološki vjesnik, 44, 289–300. garašić, m. (2021): the dinaric karst system of croatia: speleology and cave exploration.– springer international publishing, 462 p. doi: 10.1007/978-3-030-80587-6 ginés, j. (1995): l'endocarst de mallorca: els mecanismes espeleogenètics/ mallorca's endokarst the speleogenetic mechanisms.– endins: publicació d'espeleologia, 71–86. hammer, ø., harper, d.a. & ryan, p. (2001): pasτ: paleontological statistics software package for education and data analysis.– palaeon­ tologia electrónica, 4, 1–9. häuselmann, p. (2011): uis mapping grades.– international journal of speleology, 40/2, 15. jouves, j., viseur, s., arfib, b., baudement, c., camus, h., collon, p. & guglielmi, y. (2017): speleogenesis, geometry, and topology of caves: a quantitative study of 3d karst conduits.– geomorphology, 298, 86–106. doi: 10.1016/j.geomorph.2017.09.019 lauritzen, s. & lauritsen, a. (1995): differential diagnosis of para­ genetic and vadose canyons.– cave and karst science 21/2, 55–59. lauritzen, s. & lundberg, j. (2000): solutional and erosional morp­ hology of caves.– in: klimchouk, a., ford, d.c., palmer, a.n. & dreybrodt, w. (eds.): speleogenesis. evolution of karst aquifers. huntsville, national speleological society. lazaridis, g.t. (2022): definition and process-based classification of ca­ ves.– acta carsol., 51/1, 65–77. doi: 10.3986/ac.v51i1.10611 littva, j., hok, j. & bella, p. (2015): cavitonics: using caves in active tectonic studies (western carpathians, case study).– journal of structu­ ral geology, 80, 47–56. doi: 10.1016/j.jsg.2015.08.011 marinčić, s. (1997): tectonic structure of the island of hvar (southern cro­ atia).– geologia croatica, 50/1, 57–77. marjanac, s. (1956): pećine i jame otoka lastova.– speleolog, 4/1–2, 10–19. osborne, r.a.l. (2002): cave breakdown by vadose weathering.– int. j. speleol., 31/1, 37–53. doi: 10.5038/1827-806x.31.1.3 pasini, g. (2009): a terminological matter: paragenesis, antigravitative ero­ sion or antigravitational erosion?– international journal of speleology, 38/2, 129–138. doi: 10.5038/1827-806x.38.2.4 piccini, l. (2011): recent developments on morphometric analysis of karst caves.– acta carsologica, 40/1. doi: 10.3986/ac.v40i1.27 plan, l., filipponi, m., behm, m., seebacher, r. & jeutter, p. (2009): constraints on alpine speleogenesis from cave morphology – a case study from the eastern totes gebirge (northern calcareous alps, austria).– geomorphology, 106/1–2, 118–129. doi: 10.1016/j.geomorph. 2008.09.011 shanov, s. & kostov, k. (2014): dynamic tectonics and karst.– springer, 123 p. doi: 10.1007/978-3-662-43992-0 sokač, b., grgasović, t. & husinec, a. (2014): clypeina lagustensis n. sp., a new calcareous alga from the lower tithonian of the lastovo island (croatia).– geologia croatica, 67/2, 75–86. doi: 10.4154/gc.2014.06 surić, m., lončarić, r. & lončar, n. (2010): submerged caves of cro­ atia: distribution, classification and origin.– environmental earth scien­ ces, 61, 1473–1480. doi: 10.1007/s12665-010-0463-0 szczygieł, j., sobczyk, a., maciejewski, m. & fernandez, o. (2022): variscan vs. alpine structural controls: karstic proto­conduit development within palaeozoic marble post­conditioned by alpine fault­ ing (the niedźwiedzia cave, ne bohemian massif).– geomorpho­ logy, 415, 108423. doi: 10.1016/j.geomorph.2022.108423 vlahović, i., tišljar, j., velić, i. & matičec, d. (2002): the karst dinarides are composed of relics of a single mesozoic platform: facts and consequences.– geologia croatica, 55/2, 171–183. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– paleogeography paleoclimatology paleoeco­ logy, 220, 333–360. doi: 10.1016/j.palaeo.2005.01.011 white, e. & white, w. (2000): breakdown morphology.– in: kimchouk, a.b., ford, d.c., palmer, a.n. & dreybrodt, w. (eds.): speleo­ genesis: evolution of karst aquifers. huntsville, national speleological society, 2000, 427–429. zaczek-peplinska, j. & kowalska, m. (2022): evaluation of the lidar in the apple iphone 13 pro for use in inventory works.– in: xxvii fig congress, 11–15. g eologia c roatica 241lazaridis et al.: deciphering rock surface origins in a karst cave: insights from the rača cave, lastovo, croatia table s1. analytic presentation of measured discontinuities in the dataset “limestone”. structural element measured surfaced bedding 22 joint set j1 19 joint set j2 11 table s2. dataset of limestone discontinuities measured on the surface above the cave. planetype dip dipazimuth strike joint 70.1904 183.722 93.72202 joint 71.92961 186.2168 96.21678 joint 60.76754 192.3736 102.3736 joint 62.6535 192.4151 102.4151 joint 64.44534 193.5039 103.5039 joint 77.69932 197.5304 107.5304 joint 68.17551 198.4231 108.4231 joint 74.88907 199.1452 109.1452 joint 58.83289 199.8249 109.8249 joint 63.27093 199.9023 109.9023 joint 69.60873 200.4109 110.4109 joint 85.67558 200.4482 110.4482 joint 71.74333 201.4845 111.4845 joint 57.07592 203.2287 113.2287 joint 54.55397 204.0684 114.0684 joint 66.88847 205.9646 115.9646 joint 65.23213 216.743 126.743 joint 87.45946 222.5092 132.5092 joint 50.05435 230.8193 140.8193 joint 72.88331 111.2763 201.2763 joint 72.42332 292.5967 202.5967 joint 72.5682 295.1761 205.1761 joint 73.54114 295.1895 205.1895 joint 84.91031 295.4134 205.4134 joint 86.36198 296.3551 206.3551 joint 86.05621 117.4916 207.4916 joint 80.64629 302.1627 212.1627 joint 77.13354 302.394 212.394 joint 75.96823 123.3732 213.3732 joint 87.56434 304.0756 214.0756 bedding 33.92595 11.76361 281.7636 bedding 18.18498 13.17101 283.171 bedding 49.6176 22.13975 292.1398 bedding 43.83539 33.53652 303.5365 bedding 17.92305 35.95442 305.9544 bedding 34.05956 37.33838 307.3384 bedding 24.52202 39.90214 309.9021 bedding 24.21395 40.07541 310.0754 bedding 21.47653 42.40966 312.4097 bedding 23.21844 46.46361 316.4636 bedding 25.54895 46.49007 316.4901 bedding 21.27693 46.68997 316.69 bedding 26.13662 47.05231 317.0523 bedding 21.49175 50.81533 320.8153 bedding 24.11968 50.95646 320.9565 bedding 23.2489 53.51107 323.5111 bedding 15.40437 56.47585 326.4758 bedding 21.90978 56.59077 326.5908 bedding 20.95658 56.98454 326.9845 bedding 20.81037 57.46151 327.4615 bedding 15.07527 62.99094 332.9909 bedding 14.88991 76.0735 346.0735 table s3. dataset of randomly measured wall and ceiling surfaces inside the cave. dip dipazimuth strike 51.81017685 25.68552208 295.6855 38.88447952 340.7792358 250.7792 34.71315765 17.41595268 287.416 52.15966415 16.62786484 286.6279 47.99376678 353.7681274 263.7681 48.86156464 347.1168823 257.1169 60.07530594 13.40961266 283.4096 46.13370514 348.4091187 258.4091 43.0787735 2.44380283 272.4438 54.68507385 289.0726013 199.0726 50.70658493 38.46739197 308.4674 46.82404327 23.12981987 293.1298 45.12934875 32.50724792 302.5073 34.96255875 21.45202637 291.452 30.47458839 24.12602997 294.126 43.03783417 353.1479492 263.1479 43.27635574 354.4704285 264.4704 46.67576599 5.80060196 275.8006 79.74478912 359.5907593 269.5908 38.39340973 32.11775589 302.1178 43.78738022 1.73403418 271.734 47.98820877 22.04389 292.0439 53.92189026 58.53795242 328.538 15.10485268 74.88994598 344.89 55.31650925 274.9995422 184.9995 56.0885582 231.2857666 141.2858 34.16085052 182.554245 92.55425 11.69459152 57.89809036 327.8981 40.20506668 176.2858124 86.28581 86.48286438 341.5631409 251.5631 80.80680847 176.1418762 86.14188 80.18000793 175.7680359 85.76804 44.0525589 188.3782349 98.37823 16.46254921 192.9366455 102.9366 41.74983597 192.8010559 102.8011 37.04017639 202.0323181 112.0323 50.96066284 196.0754395 106.0754 51.62998581 197.9461517 107.9462 6.95496511 114.7550278 24.75503 35.15284348 197.7796936 107.7797 53.35619354 172.0287781 82.02878 63.40547562 203.5804443 113.5804 38.98209763 189.9543915 99.95439 36.01334763 189.4803619 99.48036 26.29405022 178.7600708 88.76007 47.84452438 184.2487488 94.24875 42.01301956 179.4407654 89.44077 51.16294861 179.5746765 89.57468 61.87059021 176.6659546 86.66595 55.70941544 169.532074 79.53207 18.06053925 103.279274 13.27927 30.76000023 168.9787598 78.97876 22.31475639 152.1667175 62.16672 12.49810219 85.66561127 355.6656 51.95710754 147.5499573 57.54996 17.23378563 41.6733284 311.6733 43.19434357 196.2207336 106.2207 supplement 1. g eo lo gi a c ro at ic a 242 geologia croatica 77/3 64.37724304 182.5814514 92.58145 43.95110321 185.7926483 95.79265 16.25034142 10.27902889 280.279 48.64162827 180.4055176 90.40552 57.17521667 180.3766937 90.37669 50.62455368 128.3023834 38.30238 37.45290375 176.8956909 86.89569 52.34550476 169.4284363 79.42844 21.38539886 36.22367477 306.2237 62.66679764 163.6212921 73.62129 89 163.9104157 73.91042 65.28587341 176.6878815 86.68788 69.71627045 170.976471 80.97647 51.29399872 165.8537598 75.85376 14.28626442 29.36658859 299.3666 66.05008698 165.7699432 75.76994 56.39934158 118.6528854 28.65289 25.03895378 6.43108511 276.4311 70.78977966 95.69387054 5.693871 54.30705261 135.006073 45.00607 73.24403381 315.0262451 225.0262 85.31558228 301.187439 211.1874 41.76155853 124.7254257 34.72543 38.45618439 157.5586548 67.55865 51.37637329 99.48777771 9.487778 50.13928604 135.6249085 45.62491 61.85085297 144.1279602 54.12796 68.43937683 87.5002594 357.5002 43.7901001 62.85770798 332.8577 72.55857849 118.746788 28.74679 61.11566925 149.2992249 59.29922 51.21696472 136.0491486 46.04915 51.47016525 133.4876251 43.48763 79.19998932 266.4174194 176.4174 87.05994415 339.9796753 249.9797 83.25766754 318.3826294 228.3826 32.68767929 14.32559872 284.3256 22.32835007 7.10480309 277.1048 36.77183151 2.26389885 272.2639 46.52796555 29.3073349 299.3073 35.97826767 29.97133255 299.9713 37.30485153 22.42285919 292.4229 87.18093872 349.376648 259.3766 22.72686386 23.99195671 293.9919 45.86300278 14.26215935 284.2621 87.20011902 329.190033 239.19 83.81307983 335.3583984 245.3584 44.34930038 11.4164257 281.4164 20.08646393 30.0602951 300.0603 54.93972778 5.80375576 275.8038 51.82859802 36.19450378 306.1945 27.45674896 33.88423157 303.8842 11.77245617 43.2335968 313.2336 5.56982136 340.2375794 250.2376 53.21250534 23.3540554 293.3541 35.98528671 24.30040359 294.3004 42.97766876 38.8841629 308.8842 28.94192314 314.7141113 224.7141 19.21271324 243.3904572 153.3905 38.65695953 35.6414032 305.6414 73.00608826 125.1915512 35.19155 50.79981613 196.4559631 106.456 74.38387299 121.3219833 31.32198 28.61218643 23.44040871 293.4404 37.10426712 153.8766785 63.87668 44.60998154 151.1885681 61.18857 46.7310257 22.80583572 292.8058 27.00732613 121.293747 31.29375 38.61858749 124.3654327 34.36543 42.93967056 117.3129196 27.31292 56.49079895 123.5715027 33.5715 36.60788345 158.1975555 68.19756 35.08895874 158.9268341 68.92683 20.82408524 152.7225952 62.7226 31.75463486 18.40585899 288.4059 46.60958099 206.6821899 116.6822 38.52404785 16.68103218 286.681 80.98046112 124.2035065 34.20351 43.18328857 204.8309326 114.8309 14.6488924 36.44748306 306.4475 18.79786301 51.42290497 321.4229 37.2375946 26.81740189 296.8174 table s3. continued. 2024 | 77/1 | 41–56 | 12 figs. | 6 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction dumortierite [(al,□)al6(bo3)si3o13(o,oh)2] is relatively uncommon but is the second most abundant aluminum borosilicate in the earth's crust after tourmaline. it is the most widespread member of the dumortierite group which also includes very rare magnesiodumortierite [(mg,ti,□)al4(al,mg)2(bo3)si3o12(o,oh)3] and first occurrence of dumortierite in croatia: its chemical composition and appearance as an igneous mineral in leucogranite-hosted pegmatite vesnica garašić*1, boško lugović (†)1, mirjana sekušak1, šime bilić1, hans-peter meyer2, ralf schuster3 and maja vrkljan1 1 university of zagreb, faculty of mining, geology and petroleum engineering, institute for mineralogy, petrology and mineral resources, pierottijeva 6, hr-10000 zagreb, croatia; (*corresponding author: vesnica.garasic@rgn.unizg.hr) 2 heidelberg university, faculty of chemistry and geosciences, institute of earth sciences, im neuenheimer feld 234-236, 69120 heidelberg, germany 3 geosphere austria, geophysics and applied geology, neulinggasse 38, 1030 vienna, austria doi: 10.4154/gc.2024.01 abstract in this article, dumortierite from croatia is described for the first time. dumortierite formed in a pegmatite dyke cutting through cretaceous two-mica leucogranite of the magmatic-metamorphic complex of mt. moslavačka gora. the pegmatite dyke shows a magmatic mineral association of coarse-grained quartz, orthoclase, microcline and albite, less abundant muscovite, biotite, pinkish andalusite and blue-coloured prismatic dumortierite i crystals. subsequent alteration by titanium-rich hydrothermal fluids led to partial replacement of dumortierite i and andalusite by secondary fibrous to acicular purple dumortierite ii enriched in mg and ti. during temperature decrease perthite developed in feldspars and at a still later stage, sericite partially replaced not only feldspars but also andalusite and both types of dumortierite along grain boundaries and cracks. final alteration at very low temperatures caused formation of clay minerals at the expense of feldspars. according to mineral chemical analyses, the feldspars are represented by albite and k-feldspar with a low albite component. biotite corresponds to annite and its subhedral shape and chemical composition point to magmatic crystallisation from a peraluminous melt derived from a crustal source. coarse muscovite flakes contain 1.31-1.48 wt.% feo and 0.56-0.70 wt.% tio2. their na/(na+k) ratios (0.08–0.09) prove a magmatic origin, whereas lower ratios in sericite (0.04–0.06) indicate formation during retrogression. magmatic muscovite is in textural equilibrium with andalusite, also implying an igneous origin for the latter, which belongs to the s3 textural type of andalusite in felsic igneous rocks. electron microprobe analyses clearly show a strong positive correlation between si tetrahedral deficiency (3-si) and the sum of al+ti, (r2= 0.85) in both types of dumortierite, implying al replacement by ti. however, al replacement by ti is not restricted to al in the octahedral position, as generally accepted, but most probably also in the tetrahedral position. distinct pleochroic colours in dumortierite are usually explained by the [fe/(fe+ti)]x100 factor, but according to this study, elevated mg contents stabilize red to violet coloured dumortierite at higher [fe/(fe+ti)] x100 factors than those previously suggested. dumortierite-bearing pegmatite and host two-mica leucogranite show strong chemical similarities in their major, minor and trace element contents. both rock types have a strong peraluminous character (asi = 1.6 in pegmatite vs 1.8 in leucogranite), low cao/na2o ratios (0.11 vs 0.14), high rb/ba (74.5 vs 16.4) and rb/sr ratios (78.4 vs 43.3) as well as relatively high al2o3/ tio2 ratios (261 vs 210). for the leucogranitic melt these characteristics indicate derivation from a pelitic source and low melting rates at relatively low temperatures. with respect to the field relationships and the chemical similarities, formation of the pegmatitic melt by fractional crystallisation during solidification of the two-mica leucogranite is inferred. based on the mineralogical composition, the dumortierite-bearing pegmatite from mt. moslavačka gora may be a member of the abyssal pegmatite class and the ab-bbe subclass. however, its formation by fractional crystallisation from a granitic melt argues against this interpretation, as all other dumortierite-bearing granitic pegmatites occur in high-grade metamorphic host rocks and are thought to be products of anatectic melting of country rocks. therefore, the investigated pegmatite is quite unique and not fully comparable with any previously described dumortieritebearing pegmatite worldwide. holtite [(ta,nb,□,al)al6(bo3)(si, sb,as)3o12(o,oh,□)3] (evans et al., 2012). dumortierite occurs as a minor constituent in pegmatite (fuchs et al., 2005; čempirek & novak, 2006; pieczka et al., 2011; groat et al., 2012), granite (puxeddu, 2022), aluminous regional metamorphic rocks (visser & senior, 1991; willner & schreyer, 1991; vrana et al., 2009; article history: manuscript recieved: october 18, 2023 revised manuscript accepted: november 28, 2023 available online: february 27, 2024 keywords: dumortierite, andalusite, granitic pegmatite, mt. moslavačka gora, croatia g eo lo gi a c ro at ic a geologia croatica 77/142 dokukina et al., 2017; korsakov et al., 2019) and hydrothermally altered rocks (black, 1973; taner & martin, 1993; choo & kim, 2003; khaleghl, 2019). dumortierite was first observed at chaponost, in the rhônealps near lyons, france, by m.f. gonnard in november 1879 who named the new mineral after the influential french paleontologist eugène dumortier (gonnard, 1881). the orthorhombic space group of dumortierite (pmcn) as well as its first general formula were determined by claringbull & hey (1958). its unusually complex crystal structure was resolved by golovastikov (1965). later studies revealed the presence of vacancies and water inside the crystal structure (moore & araki, 1978; werding & schreyer, 1983, alexander et al., 1986). the full occupation of the tetrahedral sites, even if there is a si-deficiency, was demonstrated by alexander et al. (1986), who explained this by al substitution for si. the same authors postulated that the blue colour of dumortierite can be attributed to fe2+-fe3+ charge transfer, and the pale red colour to fe2+-ti4+ charge transfer. the most recent refinements of the crystal structure were done by evans & groat (2012), evans et al. (2012) and groat et al. (2012) as according to them, dumortierite is strongly pseudohexagonal and contains two types of double chains of al octahedra running parallel to the c-axis. the al 2 and al 3 double chains are characterised by edge-sharing octahedra, whereas the al 4 double chain consists of face-sharing octahedral dimers. the two types of double chains are linked to one another by corner sharing and form small trigonal channels, which contain bo3 triangles and large hexagonal channels incorporating the al 1 chain of face-sharing octahedra. the a11 chain is connected to the double chain framework via six sio4 tetrahedra having two si 1 and four si 2 sites. chemical substitutions occur mostly in the hexagonal channel, for instance ti4+, mg2+, fe2+, fe3+ at a11 and al3+ at si 1 and si 2 sites (evans et al., 2012). vacancies occurring at the a11 site are charge compensated by the replacement of o atoms by oh primarily at the o2 and o7 sites (evans & groat, 2012). the aim of this study is to present the first known occurrence of dumortierite in croatia. it was found in a pegmatite dyke cutting a two-mica leucogranite of the srednja rijeka quarry (45°42'45.4''n/16°41'31.5''e). the latter is located about 5 km figure 1. tectonic map of the northern dinarides and the surrounding area showing the tectonic subdivision according to schmid et al. (2008). the position of mt. moslavačka gora within the sava suture zone is indicated by the red square. g eologia c roatica garašić v. et al.: first occurrence of dumortierite in croatia: its chemical composition and appearance as an igneous mineral in leucogranite-hosted ... 43 southeast of the city of čazma in the northern part of mt. moslavačka gora (fig. 1, 2). based on petrographic, mineral, chemical and whole rock geochemical data, the mineralogy of dumortierite, the host pegmatite and the surrounding leucogranite are described and their genetic relationships discussed. finally, data from the studied locality are compared to other dumortierite-bearing pegmatite occurences worldwide. 2. geological setting the described dumortierite occurs in one of the pegmatite dykes cutting a late cretaceous two-mica leucogranite of the magmatic-metamorphic complex of mt. moslavačka gora (fig. 2). the crystalline complex forms an inselberg of about 180 km2 in the southwestern part of the pannonian basin, which is filled by neogene and quaternary sediments (pamić, 1990). regarding its position in the regional tectonic framework, the magmaticmetamorphic complex of mt. moslavačka gora was previously deemed to be a part of the tisia mega unit (pamić, 1998; pamić & jurković, 2002), which is characterised by a variscan metamorphic basement. however, more recent studies recognised a dominant cretaceous igneous and metamorphic imprint (balen & petrinec, 2011) and, therefore, it is nowadays attributed to the sava zone, forming the suture between europe and the adriaderived tectonic units in the pannonian basin and the dinarides (schmid et al., 2008) (fig. 1). the magmatic-metamorphic complex of mt. moslavačka gora is composed of highto medium-grade (predominantly migmatite and orthoand paragneiss) and medium-grade metamorphic rocks (mostly micaschist and amphibolite), with rare intercalations of quarzite and marble (tućan, 1953; barić, 1972; crnko & vragović, 1990; garašić, 1993; balen et al., 2000). this sequence is intruded by various types of granitic rocks, such as two-mica granite, granodiorite, monzogranite and leucogranite (crnko & vragović, 1990; pamić, 1990) as well as different types of gabbro (kišpatić, 1887; tućan, 1953; pamić, 1987; balen et al., 2003). besides the common granite minerals (quartz, k-feldspar, acid plagiclase, biotite and muscovite), andalusite, sillimanite and tourmaline were recognised in some granitic bodies of mt. moslavačka gora (cohen, 1887; kišpatić, 1887; crnko & vragović, 1990; garašić et al. 2007; balen, 2007; balen & petrinec, 2010; balen & broska, 2011). pegmatite and aplite dykes are scarce in the medium-grade metamorphic rocks, but are more frequent and thicker in migmatite and particularly in the granitic rocks (tućan, 1904; crnko & vragović, 1990). the latter also contain different types of enclaves, “forfigure 2. geological sketch map of the mt. moslavačka gora area modified after crnko (1990) and korolija & crnko (1985). the investigated dumortieritebearing pegmatite is located at srednja rijeka quarry (45°42'45.4''n/16°41'31.5''e) and the sample location is marked by a star symbol. g eo lo gi a c ro at ic a geologia croatica 77/144 eign“ (gneiss, amphibolite xenoliths, etc,) and „cognate“ (tourmaline nodules), ranging in size from a few millimetres up to hundreds of metres in size. according to a study by balen & petrinec (2010), they indicate a complex evolution for at least some of the granitic rocks of mt. moslavačka gora. geochronological age data indicate a prolonged period of geological evolution of the magmatic-metamorphic complex of mt. moslavačka gora. zircon dating revealed an early ordovician age (486-491 ma) for the granitic rocks now metamorphosed to orthogneiss (starijaš et al., 2010). the granulite facies lp/ ht metamorphic overprint at ~750°c and 3–4 kbar occured in the early late cretaceous at about 90 to 100 ma, as indicated by monazite dating of metapelites (starijaš et al. 2010). this is in agreement with amphibole ar-ar cooling ages of 80-90 ma determined for amphibolites (balen et al. 2001). according to the zircon ages of starijaš et al. (2010), the two-mica leucogranite crystallised in a late phase of the cretaceous metamorphic event at 82±1 ma. subsequent cooling is documented by arar muscovite ages of 73±1 and 74±1 ma measured in both the pegmatite and two-mica leucogranite (palinkaš et al., 2000; balen et al. 2001). 3. analytical methods the chemistry of dumortierite and associated minerals in the studied dumortierite-bearing pegmatite was investigated using the cameca sx51 electron microprobe, equipped with five wavelength-dispersive crystal spectrometers, at the mineralogical institute of the university of heidelberg (germany). the following operating conditions were applied: accelerating voltage of 15 kv, beam current of 20 na, about 1 μm beam diameter and 10 s counting time for all elements. calibration standards included natural and synthetic silicates and oxides. the cameca pap matrix correction program was applied to the raw data. whole rock chemical analyses were performed by bureau veritas commodities canada ltd.. inductively coupled plasma optical emission spectroscopy (icp-oes) was used for the determination of major and minor elements with detection limits ranging from 0.04 to 0.002 wt.%, and inductively coupled plasma mass spectrometry (icp-ms) for the trace elements showing detection limits in the range from 8 to 0.01 ppm. 4. petrography the dumortierite-bearing pegmatite dyke is up to 6 cm thick. it consists of coarse-grained quartz, orthoclase, microcline and albite, less abundant muscovite, biotite, pinkish andalusite and blue-coloured dumortierite crystals. in hand specimens (fig. 3) and back-scattered electron (bse) images (fig. 4), the rock shows no indications of postmagmatic deformation. quartz grains are irregularly shaped, often with amoeboid grain boundaries. in cross polarised light they show weak undulose extinction. they commonly enclose smaller flakes of biotite and/or muscovite. microcline grains vary in size from 1.0 up to 3.5 mm whereas orthoclase grains are usually coarser (up to 6.0 mm). both k-feldspars are subhedral to anhedral in shape, perthitic (fig. 4b) and partially altered to sericite and clay minerals. fine-grained intergrowths of quartz and microcline are also observed. biotite flakes and quartz grains are locally enclosed in orthoclase. albite occurs as subhedral to anhedral grains with common polysynthetic twinning lamellae and varies in size from 4.0 to 15.0 mm (fig. 4a). it contains various mineral inclusions: microcline, biotite, quartz and dumortierite and also shows alteration to sericite and clay minerals. muscovite forms subhedral to anhedral flakes up to 0.7 mm in size (fig. 4a). in some cases, it is intergrown with biotite at the rims. tiny muscovite (sericite) flakes or aggregates occur at the rims and within cracks of andalusite and dumortierite (fig. 4b). biotite flakes vary in size from 0.5 up to 1.9 mm and are commonly subhedral in shape (fig. 4a). they are pleochroic ranging from light brown to deep brown (fig. 5). andalusite occurs as prismatic euhedral to subhedral crystals ranging from 0.1 to 0.5 mm in thickness and from 0.2 to 0.9 mm in length. it shows strong pleochroism from colourless and pale pinkish to pink colour (fig. 5). the colour is not homogeneous but partly shows a normal concentric zoning with straight to curved gradational boundaries, but sector zoning is also observed. at the rims, andalusite shows replacement by polycrystalline sericite aggregates and dumortierite (dum ii) (fig. 5). the microscopic studies identified two types of dumortierite crystals: dum i and dum ii. the dum i crystals are subhedral, prismatic and up to 26 mm in size. they are strongly pleochroic ranging from colourless to azure blue (fig. 6). dum ii represents bundles of parallel fibrous or acicular crystals, which figure 3. hand specimens of dumortierite-bearing pegmatite from the srednja rijeka quarry in mt. moslavačka gora. a) fine-grained leucogranite (right side) and coarse-grained pegmatite with bluish dumortierite (left side). both rock types consist of white feldspars, grey quartz, black biotite, silvery-white muscovite and tiny pale pinkish andalusite. b) pegmatite composed of white feldspars, grey quartz, black biotite flakes and blue dumortierite. g eologia c roatica garašić v. et al.: first occurrence of dumortierite in croatia: its chemical composition and appearance as an igneous mineral in leucogranite-hosted ... 45 are up to 1.4 mm long. their strong pleochroism ranges from colourless to red-violet (fig. 7). a zoned subhedral prismatic dumortierite crystal is also observed. it exhibits a blue to colourless pleochroic core overgrown by a colourless to red-violet pleochroic rim (fig. 8). small muscovite flakes (sericite) replace both types of dumortierite along rims and cracks (fig. 4b). figure 4. back-scattered electron (bse) images of dumortierite-bearing pegmatite. a) the mineral assemblage includes coarse-grained quartz (qtz), k-feldspar (kfs), albite (ab), muscovite (ms), biotite (bt) and andalusite (and). b) perthitic k-feldspar (kfs), albite (ab) slightly altered to sericite (ser) and dumortierite (dum i), which is replaced by sericite (ser) along the cracks. figure 5. photomicrographs of andalusite (and), showing strong pleochroism from pale pinkish to pink colour and zoning expressed by the intensity of the colour. it is slightly replaced by sericite and ti-rich red-violet dumortierite (dum ii) at the rims. biotite (bt) flakes are pleochroic from light brown to deep brown. figure 6. photomicrographs of dumortierite i (dum i) showing strong pleochroism from pale blue to colourless. the subhedral prismatic crystal is associated with k-feldspar and albite intensely altered to dark brown clay minerals. g eo lo gi a c ro at ic a geologia croatica 77/146 5. mineral chemistry chemical compositions of feldpars are given in table 1. their chemical formulae were calculated on the basis of 8 oxygens and the total fe was determined as feo. the analysed plagioclase ab91-98an1.4-8or0.6-1 corresponds to albite, whereas k-feldspar contains only minor na (0.069 to 0.105 pfu). the fe content is very low, varying from 0.000 to 0.001 pfu in albite and from 0.000 to 0.003 pfu in k-feldspar. the chemistry of mica minerals is shown in table 2. their chemical formulae were calculated on the basis of 11 (o,oh) and total fe as fe2o3 for muscovite but as feo for biotite. coarse muscovite flakes (analyses mg-27 and mg-28) and fine-grained muscovite (sericite) replacing andalusite and dumortierite (analyses mg-02, mg-04, mg-11, mg-14) show compositional differences. the coarse muscovite flakes are richer in ti (0.0280.034 pfu), fe (0.073-0.082 pfu), mg (0.033-0.040 pfu) and na (0.078-0.082 pfu) but poorer in altot (2.786-2.827 pfu) than the sericite (ti = 0.003-0.013 pfu, fe = 0.000-0.031 pfu, mg = 0.0030.011 pfu, altot = 2.873-2.924 pfu). the analysed biotite flakes are characterised by high altot (1.852-1.894 pfu) and high fe (1.737-1.776 pfu), have a moderate variation in aliv (1.336-1.373 pfu) and a narrow range of high fe2+/(fe2++mn+mg) ratios (0.829 to 0.836). this corresponds to a common annite composition according to the classification diagram of deer et. al. (1982). the concentration of ti varies from 0.165 to 0.173 pfu. the content of k is in the range of 0.895 and 0.930 pfu and na ranges from 0.010 to 0.013 pfu, yielding low na/(na+k) ratios (0.010 to 0.014). the chemical composition of andalusite is displayed in table 3. the chemical formulae of andalusite were calculated on the basis of 3 cations and 5 oxygens and total fe as fe2o3. except for si and al, only fe shows a noticeable concentration varying from 0.016 to 0.017 pfu. the distribution of fe is not homogeneous but produces a chemical zoning. the zoning is expressed by the intensity of the pinkish colour, whereby the colour intensity is positively correlated with the fe content. the chemical composition of dumortierite is presented in table 4. its chemical formulae were calculated on the basis of 17 (o,oh), assuming that the contents of b2o3 and h2o correspond to 6.20 wt. % and 1.30 wt. %, respectively, in accordance with the measured values of these components in fuchs et al. (2005). the dum i crystals occurring as large prismatic grains have lower mg contents (0.033-0.055 pfu) and ti (0.001-0.011 pfu) than the smaller dum ii crystals occurring as fibrous or acicular crystals (mg: 0.047-0.087 pfu; ti: 0.043-0.064 pfu). the differences in fe abundance (0.038-0.072 pfu vs 0.037-0.057 pfu) and al/si ratios (2.35-2.47 vs 2.27-2.49) are not significant. a si deficiency (<3.0 pfu) is observed in 95% of the epma spot analyses. 6. bulk chemistry of dumortierite-bearing pegmatite and two-mica leucogranite the chemical composition of dumortierite-bearing pegmatite (sample mg-d-pg-13) and host two-mica leucogranite (sample mg-d-g13) is given in table 5. the two rocks show great similarities with respect to both major and trace elements, and the obtained values are in accordance with published analyses for leucogranite from srednja rijeka from balen & petrinec (2011). with respect to the major elements, the investigated rocks are characterised by high contents of sio2 (72.67 in pegmatite versus 75.30 wt. % in leucogranite), al2o3 (15.63 vs 14.67 wt. %) and na2o (3.35 vs 3.58 wt. %), and low contents of tio2 (0.06 vs 0.07 wt. %), fe2o3 (0.55 vs. 0.79 wt. %), mgo (0.06 vs 0.08 wt. figure 7. photomicrographs of dumortierite ii (dum ii) showing strong pleochroism from very pale violet to colourless. dumortierite forms bundles of parallel fibrous or acicular crystals in a mineral assemblage with pleochroic light to deep brown biotite (bt) and feldspar (fsp), which is strongly altered to dark brown clay minerals. figure 8. a photomicrograph of a zoned prismatic dumortierite crystal exhibiting a blue to colourless pleochroic core overgrown by a colourless to red violet pleochroic rim. g eologia c roatica garašić v. et al.: first occurrence of dumortierite in croatia: its chemical composition and appearance as an igneous mineral in leucogranite-hosted ... 47 %) and cao (0.36 vs 0.51 wt. %). only the k2o content is significantly higher in dumortierite-bearing pegmatite (6.13 wt.%) than in the host two-mica leucogranite (3.86 wt.%). the aluminium-saturation index (asi), which is defined by the molar ratio of al2o3/(cao+na2o+k2o), is comparable (1.6 vs. 1.8), indicating a strong peraluminous character of the rocks. in comparison to the host two-mica leucogranite, the dumortierite-bearing pegmatite is slightly enriched in co (4.5 vs 0.2 ppm), rb (298 vs 229 ppm) and pb (22.0 vs 5.3 ppm), but depleted in ba (4 vs 14 ppm). low concentrations of sr (3.8 and 5.3 ppm) and zr (31.9 and 29.8 ppm) are typical for both rock types. the trace element compositions normalised to the upper continental crust (taylor & mclennan, 1985) demonstrate great similarities (fig. 9a). both rocks exhibit a slight, up to threefold enrichment in cs, rb, k and ta, whereas all other trace elements are depleted. the depletion is strong for ba and sr but only moderate for zr and ti. the rare earth element (ree) concentrations of dumortierite-bearing pegmatite and the host two-mica leucogranite are presented in table 6. the eu value for dumortierite-bearing pegmatite is missing because it is below the detection limit. the total sum of ree (σree) is low (18.15 and 17.85 ppm) and the individual ree abundances are 5 to 15 times higher than those in chondrite (sun & mcdonough, 1989). in the chondrite normalised ree diagram, the investigated rocks display identical ree patterns. they are relatively flat with a weak m-type tetrad effect (fig. 9b) and a pronounced negative eu anomaly (eu/eu* = 0.06 for pegmatite and 0.08 for leucogranite, where table 1. electron microprobe compositions of feldspars. mineral albite k-feldspars analysis mg-06 mg-08 mg-10 mg-22 mg-23 mg-09 mg-25 mg-26 sio2 68.25 67.64 67.72 66.02 65.89 64.39 64.74 64.57 tio2 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 al2o3 19.99 20.07 20.54 21.51 21.51 18.95 18.84 18.69 cr2o3 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 feo 0.01 0.00 0.00 0.03 0.03 0.03 0.01 0.09 mno 0.00 0.00 0.00 0.05 0.04 0.00 0.00 0.00 cao 0.29 0.32 0.56 1.78 1.79 0.00 0.00 0.00 na2o 11.74 11.53 11.32 10.87 10.74 0.77 1.17 1.03 k2o 0.13 0.17 0.18 0.14 0.20 15.53 14.61 15.08 σ 100.41 99.73 100.32 100.41 100.21 99.67 99.37 99.46 si 2.974 2.967 2.953 2.891 2.891 2.978 2.989 2.988 ti 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 al 1.026 1.038 1.056 1.110 1.112 1.033 1.025 1.019 cr 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 fe2+ 0.000 0.000 0.000 0.001 0.001 0.001 0.000 0.003 mn 0.000 0.000 0.000 0.002 0.001 0.000 0.000 0.000 ca 0.014 0.015 0.026 0.084 0.084 0.000 0.000 0.000 na 0.991 0.981 0.957 0.923 0.914 0.069 0.105 0.092 k 0.007 0.010 0.010 0.008 0.011 0.916 0.861 0.890 σ 5.012 5.009 5.002 5.019 5.015 4.998 4.981 4.994 chemical formula was calculated on the basis of 8 oxygen and total fe was determined as feo. figure 9. chemical composition of dumortierite-bearing pegmatite and two-mica leucogranite from mt. moslavačka gora. a) trace element composition normalised to the upper continental crust with the values from taylor & mclennan (1985). b) chondrite-normalised ree pattern using the values from sun & mcdonough (1989). g eo lo gi a c ro at ic a geologia croatica 77/148 ta bl e 2. e le ct ro n m ic ro pr ob e co m po si tio ns o f m ic as . m in er al m us co vi te m in er al bi ot ite a na ly si s m g -0 2 m g -0 4 m g -1 1 m g -1 4 m g -2 7 m g -2 8 a na ly si s m g -2 4 m g -2 9 m g -3 0 m g -3 2 m g -3 1 fin egr ai ne d fin egr ai ne d fin egr ai ne d fin egr ai ne d co ar se -g ra in ed co ar se -g ra in ed si o 2 45 .8 1 45 .9 3 46 .4 8 47 .1 0 45 .8 9 46 .5 7 si o 2 33 .2 4 33 .3 0 33 .3 9 32 .1 5 33 .6 7 ti o 2 0. 06 0. 07 0. 07 0. 27 0. 56 0. 70 ti o 2 2. 77 2. 76 2. 80 2. 69 2. 90 a l 2o 3 37 .1 4 37 .0 0 36 .6 3 37 .2 2 36 .1 8 35 .9 0 a l 2o 3 19 .9 7 19 .8 5 19 .8 6 19 .6 6 19 .8 7 cr 2o 3 0. 03 0. 00 0. 00 0. 01 0. 00 0. 00 cr 2o 3 0. 00 0. 06 0. 00 0. 02 0. 01 fe o 0. 05 0. 00 0. 04 0. 56 1. 31 1. 48 fe o 26 .7 4 26 .7 2 26 .4 5 25 .6 7 26 .2 5 m no 0. 01 0. 00 0. 00 0. 00 0. 10 0. 00 m no 0. 84 0. 77 0. 89 0. 87 0. 93 m go 0. 03 0. 04 0. 05 0. 11 0. 34 0. 41 m go 2. 48 2. 51 2. 46 2. 37 2. 51 ca o 0. 00 0. 00 0. 00 0. 01 0. 00 0. 01 ca o 0. 00 0. 01 0. 00 0. 00 0. 00 n a 2 o 0. 44 0. 40 0. 24 0. 27 0. 61 0. 65 n a 2 o 0. 08 0. 06 0. 08 0. 08 0. 08 k 2 o 10 .5 4 10 .6 6 10 .3 9 10 .0 6 10 .2 9 9. 82 k 2 o 8. 97 8. 89 9. 09 8. 92 8. 87 σ 94 .1 0 94 .1 1 93 .8 9 95 .6 1 95 .2 7 95 .5 2 σ 95 .0 8 94 .9 5 95 .0 3 92 .4 1 95 .0 8 si 3. 06 0 3. 06 9 3. 10 3 3. 08 5 3. 04 1 3. 06 7 si 2. 64 0 2. 64 7 2. 65 1 2. 62 7 2. 66 4 ti 0. 00 3 0. 00 3 0. 00 4 0. 01 3 0. 02 8 0. 03 4 ti 0. 16 6 0. 16 5 0. 16 7 0. 16 5 0. 17 3 a l 2. 92 4 2. 91 4 2. 88 1 2. 87 3 2. 82 7 2. 78 6 a l 1. 86 9 1. 85 9 1. 85 9 1. 89 4 1. 85 2 cr 0. 00 1 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 cr 0. 00 0 0. 00 4 0. 00 0 0. 00 1 0. 00 0 fe 3+ 0. 00 3 0. 00 0 0. 00 2 0. 03 1 0. 07 3 0. 08 2 fe 2+ 1. 77 6 1. 77 6 1. 75 7 1. 75 4 1. 73 7 m n 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 5 0. 00 0 m n 0. 05 6 0. 05 2 0. 06 0 0. 06 0 0. 06 2 m g 0. 00 3 0. 00 4 0. 00 4 0. 01 1 0. 03 3 0. 04 0 m g 0. 29 3 0. 29 8 0. 29 1 0. 28 8 0. 29 6 ca 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 0 0. 00 1 ca 0. 00 0 0. 00 1 0. 00 0 0. 00 0 0. 00 0 n a 0. 05 7 0. 05 2 0. 03 0 0. 03 4 0. 07 8 0. 08 2 n a 0. 01 2 0. 01 0 0. 01 2 0. 01 3 0. 01 2 k 0. 89 8 0. 90 9 0. 88 5 0. 84 1 0. 87 0 0. 82 5 k 0. 90 9 0. 90 2 0. 92 1 0. 93 0 0. 89 5 σ 6. 95 0 6. 95 1 6. 91 0 6. 88 8 6. 95 5 6. 91 8 σ 7. 72 0 7. 71 2 7. 71 8 7. 73 2 7. 69 1 n a/ (n a+ k) 0. 06 0 0. 05 4 0. 03 3 0. 03 9 0. 08 2 0. 09 1 n a/ (n a+ k) 0. 01 3 0. 01 0 0. 01 3 0. 01 3 0. 01 4 a liv 1. 36 0 1. 35 3 1. 34 9 1. 37 3 1. 33 6 a lvi 0. 50 9 0. 50 6 0. 51 0 0. 52 1 0. 51 6 fe +m n+ m g 2. 12 5 2. 12 5 2. 10 8 2. 10 2 2. 09 5 fe /( fe +m n+ m g) 0. 83 6 0. 83 6 0. 83 3 0. 83 4 0. 82 9 ch em ic al fo rm ul as w er e ca lc ul at ed o n th e ba si s o f 1 1 (o , o h ) a nd to ta l f e w as d et er m in ed a s f e 2 o 3 f or m us co vi te , a nd a s f eo fo r b io tit e. g eologia c roatica garašić v. et al.: first occurrence of dumortierite in croatia: its chemical composition and appearance as an igneous mineral in leucogranite-hosted ... 49 eu/eu* = eun/(√(smn*gdn)). the (la/yb)n ratios, usually used for the evaluation of ree fractionation, are low and very similar in both rocks (1.74 and 2.39). 7. discussion 7.1. mineral chemistry and ion substitutions in dumortierite two types of dumortierite can be distinguished in the studied pegmatites on the basis of their textural and optical properties. the large prismatic dum 1 grains with the colourless to azure blue pleochroism and dum ii appearing as smaller bundles of parallel fibrous or acicular crystals with a colourless to red-violet pleochroism are also characterised by their different chemical compositions. dum i crystals have lower contents of mg and ti (0.033-0.055 pfu and 0.001-0.011 pfu) than dum ii (0.047-0.087 pfu and 0.043-0.064 pfu.), whereas the difference in fe2+ is not significant (table 4). however, it is interesting to note, that fe2+ shows a moderately negative correlation with the sum of ti and mg in dum i, but a clear positive correlation in dum ii (fig. 10a). table 3. electron microprobe compositions of andalusite. analysis mg-19 mg-20 sio2 36.23 35.97 tio2 0.06 0.04 al2o3 62.82 62.88 cr2o3 0.00 0.03 feo 0.72 0.76 mno 0.00 0.03 σ 99.83 99.72 si 0.981 0.976 ti 0.001 0.001 al 2.006 2.011 cr 0.000 0.001 fe3+ 0.016 0.017 mn 0.000 0.001 σ 3.006 3.010 chemical formulas were calculated on the basis of 13 cations and 5 oxygen, and total fe as fe2o3. table 4. electron microprobe compositions of selected durmotierite analyses. analysis mg-06-1 mg-06-3 mg-06-5 mg-06-7 mg-06-12 mg-06-13 dum i dum i dum i dum i dum ii dum ii prismatic prismatic prismatic prismatic fibrous fibrous crystal crystal crystal crystal aggregate aggregate sio2 30.26 29.57 30.29 30.43 29.79 31.16 tio2 0.04 0.13 0.04 0.15 0.72 0.59 b2o3* 6.20 6.20 6.20 6.20 6.20 6.20 al2o3 62.15 61.87 61.65 61.42 60.75 60.09 cr2o3 0.02 0.00 0.01 0.03 0.06 0.02 feo 0.68 0.76 0.89 0.64 0.58 0.70 mno 0.05 0.04 0.02 0.03 0.02 0.01 mgo 0.25 0.25 0.24 0.26 0.48 0.60 cao 0.01 0.03 0.01 0.00 0.00 0.00 na2o 0.01 0.02 0.02 0.02 0.01 0.00 k2o 0.00 0.01 0.00 0.01 0.00 0.02 h2o* 1.30 1.30 1.30 1.30 1.30 1.30 σ 100.96 100.16 100.66 100.49 99.90 100.68 si 2.926 2.887 2.940 2.956 2.916 3.022 ti 0.003 0.009 0.003 0.011 0.053 0.043 b 1.035 1.045 1.039 1.040 1.047 1.038 al 7.083 7.119 7.054 7.032 7.008 6.869 cr 0.002 0.000 0.001 0.002 0.005 0.002 fe2+ 0.055 0.062 0.072 0.052 0.047 0.057 mn 0.004 0.003 0.002 0.003 0.002 0.001 mg 0.036 0.036 0.034 0.037 0.070 0.086 ca 0.001 0.003 0.001 0.000 0.000 0.000 na 0.002 0.004 0.003 0.003 0.001 0.000 k 0.000 0.001 0.000 0.001 0.000 0.003 h 0.839 0.847 0.842 0.842 0.849 0.841 σ 10.949 10.970 10.952 10.939 10.950 10.922 al/si 2.42 2.47 2.40 2.38 2.40 2.27 [fe/(fe+ti)]x100 95 87 96 82 47 57 chemical formulas were calculated on the basis of 17 oxygens, total fe as feo. *it is assumed that b2o3 = 6.20 wt. % and h2o =1.30 wt. %, on the basis of paper fuchs et al. (2005). g eo lo gi a c ro at ic a geologia croatica 77/150 this indicates complex substitution reactions which will depend on many factors, including bulk chemistry of the host rock, fluid composition and p-t conditions. the differences in chemical composition certainly affect the pleochroic colours of dumortierite. alexander et al. (1986) tried to explain distinct pleochroic colours in dumortierites by an [fe/(fe+ti)]x100 factor. they postulated a pale red colour at [fe/(fe+ti)]x100 < 25, a purple colour at [fe/(fe+ti)]x100 = 25 and a blue colour at [fe/ (fe+ti)]x100 >25. however, according to the data presented in this study, the blue pleochroic colour appears at [fe/(fe+ti)]x100 = 82 99, while in contrast to the study of alexander et al. (1986), the red to violet pleochroic colour is observed at [fe/ (fe+ti)]x100 = 38 – 57 (table 4, fig. 10b). the deviating results could be due to a slightly different chemical composition of the examined dumortierite crystals. the samples used by alexander et al. (1986) are characterised by lower mg contents (mostly less than 0.020 pfu) and lower [fe/(fe+ti)]x100 ratios (mostly less than 32) than the dumortierite crystals investigated in this study. interestingly, the red to violet pleochroic dumortierite from this study shows a strong positive correlation between [fe/(fe+ti)]x100 and mg content (fig. 10b). this may indicate a stabilisation of the red to violet colour by mg even at [fe/(fe+ti)]x100 factors exceeding 25. the si tetrahedral deficiency in dumortierite is conventionally balanced by al, based on the evidence of tetrahedral al in natural (alexander et al., 1986) and synthetic dumortierite (werding & schreyer, 1983). in this study, not only is the si tetrahedral deficiency confirmed, but there is also a positive correlation between 3-si and al (r2 = 0.51). the correlation is moderate if dum i and dum ii are taken together, but is better when the two types are considered separately (fig. 10c). however, when ti is included in the substitution, there is a strong cortable 5. the major and trace element analyses of dumortierite bearing pegmatite and two-mica leucogranite. dumortierite bearing pegmatite two-mica leucogranite sample mg-d-pg13 mg-d-g13 wt.% sio2 72.67 75.3 tio2 0.06 0.07 al2o3 15.63 14.67 cr2o3 <0,002 <0,002 fe2o3 0.55 0.79 mno 0.02 0.03 mgo 0.06 0.08 cao 0.36 0.51 na2o 3.35 3.58 k2o 6.13 3.86 p2o5 0.28 0.25 loi 0.9 0.8 tot/c <0,02 <0,02 tot/s <0,02 <0,02 σ 99.99 99.98 asi 1.60 1.80 al2o3/tio2 261.00 210.00 cao/na2o 0.11 0.14 ppm ba 4 14 be <1 2 co 4.5 0.2 cs 9.0 10.9 ga 18.6 19.2 hf 1.2 1.4 nb 13.3 17.7 rb 297.9 229.4 sn 10 13 sr 3.8 5.3 ta 2.3 2.8 th 1.1 1.0 u 2.2 2.3 v <8 <8 w 3.8 2.7 zr 31.9 29.8 y 9.1 9.4 mo <0,1 <0,1 cu 1.1 0.4 pb 22.0 5.3 zn 36 28 ni 1.9 0.5 as 1.4 1.7 cd 0.1 <0,1 sb 0.1 <0,1 bi 5.4 2.3 ag 0.1 <0,1 au 28.6 17.7 hg 0.01 <0,01 tl 0.2 0.3 se <0,5 <0,5 sc 6 7 rb/ba 74.5 16.4 rb/sr 78.4 43.3 table 6. ree composition of dumortierite bearing pegmatite and two-mica leucogranite. ppm dumortierite bearing pegmatite two-mica leucogranite sample mg-d-pg13 mg-d-g13 la 2.50 3.00 ce 6.00 5.70 pr 0.77 0.77 nd 2.50 2.20 sm 0.89 0.94 eu <0,02 0.03 gd 1.13 1.15 tb 0.23 0.24 dy 1.52 1.66 ho 0.29 0.29 er 0.98 0.71 tm 0.13 0.13 yb 1.03 0.90 lu 0.16 0.13 σree 18.15 17.85 eu/eu* 0.06 0.09 (la/yb)n 1.74 2.39 g eologia c roatica garašić v. et al.: first occurrence of dumortierite in croatia: its chemical composition and appearance as an igneous mineral in leucogranite-hosted ... 51 relation between 3-si and al+ti (r2 = 0.85). this suggests that ti replaces not only al in the octahedral position, as generally accepted (evans et al., 2012), but also together with al it substitutes for si in the tetrahedral position (fig. 10d). the results of this study clearly indicate that higher al and ti contents in the crystal structure compensate for a higher si tetrahedral deficiency. werding & schreyer (1990) found that dumortierites synthesised at low pressures (3-5 kbar) exhibit higher al/si ratios of 2.77-2.94 than those synthesised at high pressures (15 to 20 kbar), which yield al/si ratios of 2.33-2.55. in this study, the measured al/si ratios for dum i and dum ii range from 2.35-2.47 and 2.27-2.49, respectively (table 4). this might be interpreted as crystallisation of the investigated dumortierite at elevated pressure. however, due to the presence of magmatic andalusite in the mineral assemblage of the pegmatite, pressures of >5 kbar can be excluded. this supports the assumption by werding & schreyer (1990), who proposed that the al/si ratio of natural dumortierite depends not only on the pressure but also on additional components (fe, mg, ti) present in its crystal structure. 7.2. mineral chemistry of mica minerals and their origin in the investigated dumortierite-bearing pegmatite two types of muscovite can be distinguished. coarse muscovite flakes are in textural equilibrium with the other minerals of the pegmatite mineral assemblage and are obviously of magmatic origin. in contrast, tiny flakes of retrograde muscovite (sericite) partly replace k-feldspar, andalusite and dumortierite along the crystal rims and cracks. they also show chemical differences, as the coarse flakes are richer in ti, fe, mg and na but poorer in al than sericite (table 2). furthermore, the coarse muscovite flakes are characterised by na/(na+k) ratios of 0.08 to 0.09, whereas in the sericite the na/(na+k) ratios range from 0.04 to 0.06. these values prove a magmatic origin for the coarse muscovite flakes, because according to monier et al. (1984), the na/(na+k) ratios in muscovite of magmatic origin are greater than 0.06. the chemical composition of magmatic biotite depends on the chemistry of the parent magma and therefore might be used to estimate the pressure-temperature conditions during crystallisation, the chemical affinity and the origin of the plutonic host rock (tang et al., 2019). nevertheless, due to the sensitivity of the biotite chemistry to the coexisting mineral assemblage, subsequent hydrothermal activity and metamorphic overprinting, its primary composition may be disturbed. therefore, caution is recommended when using discrimination and petrogenetic diagrams involving biotite chemistry (samadi et al., 2021). all analysed biotite flakes of the dumortierite-bearing pegmatite are classified as annite. its magmatic origin is supported both by petrographic criteria, such as a subhedral morphology (fig. 4a, 5a and 5b), and also by its chemical composition. in the ternary tio2*10(feo+mno)-mgo diagram of nachit et al. (2005), all biotite figure 10. chemical composition of dumortierite from mt. moslavačka gora. a) fe2+ vs (ti+mg) diagram showing a clear positive correlation between fe2+ and the sum of ti and mg in the crystal lattice of red to violet dum ii but a moderately negative correlation for blue dum i crystals. b) in the mg2+ vs [fe/(fe+ti)]x100 ratio diagram, a strong positive correlation is visible for dum ii, whereas dum i shows a moderately negative correlation. c) in the altot vs 3-si diagram, all dumortierite analyses taken together show a badly defined moderately positive correlation (r2 = 0.51) but when considering dum i and dum ii separately, a well defined correlation is visible. d) in the altot +ti vs 3-si diagram, a strong positive correlation (r2 = 0.85) is visible, suggesting that ti in dumortierite replaces not only al in octahedra, but also together with al may substitute for si in the tetrahedral position. g eo lo gi a c ro at ic a geologia croatica 77/152 analyses plot in the field of primary magmatic biotite (fig. 11a). the aluminum-saturation of the host magma can be estimated by plotting the biotite analyses in the ternary mgo-feotot-al2o3 diagram of abdel-rahman (1994). in this diagram, the biotite analyses indicate the peraluminous nature of the dumortierite-bearing pegmatite (fig. 11b). the source of the biotite parental melt was determined with the feotot /(feotot + mgo)-mgo diagram by zhou (1986), which indicates a crustal source for the biotite (fig. 12). the content of ti in biotite is extensively used as a geothermometer. however, the incorporation of ti in biotite is additionally influenced by the biotite crystal chemistry (especially the mgo/(mgo+feo) ratio), the mineral assemblage of the host rock and the pressure (henry et al., 2005). biotites from dumortierite-bearing pegmatite are not suitable for geothermometry for several reasons: i) the measured xmg = mg/(mg+fe) values are 0.141 to 0.146 and, therefore, outside of the calibration range of the ti-in-biotite geothermometer after henry et al. (2005), which is calibrated for xmg = 0.275-1.000; and ii) the absence of minerals indicating ti-saturation, such as ilmenite or rutile. both reasons may lead to underestimated temperatures. a strong positive correlation between the total al (tal) content in biotite and the solidification pressure of the host granitic rock was found by uchida et al. (2007). they expressed this correlation as an empirical equation: p (kb) = 3.03 x tal-6.53 (±0.33) where tal is the total al content in biotite, calculated on the basis of 22 oxygens. using this geobarometer, an approximate solidification pressure of 4.70 to 4.95 kbar (470 to 495 mpa) is estimated for the studied dumortierite-bearing pegmatite. this is consistent with solidification at a depth of 15.7 to 16.5 km. however, this pressure range is not in accordance with the presence of andalusite in the mineral assemblage of the dumortierite-bearing pegmatite. even though there is an ongoing discussion about the precise location of the al2sio5 triple point in the p-t space, most petrologists agree that it is somewhere between 3.8 kbar at 500⁰c and 4.5 kbar at 550⁰c (pattison, 2001). most probably, the primary biotite composition was changed during late magmatic/ hydrothermal activity and no precise pressure conditions can be determined from the biotite. 7.3. chemistry of andalusite and its origin in andalusite the chemical substitution of si and al is restricted to only a few trace elements such as fe, mn, ti and cr. in a comprehensive paper on magmatic andalusite, clarke et al. (2005) found that feo contents in the range of 0.08 to 1.71 wt% are typical of andalusite of magmatic origin. in the andalusite of the dumortierite-bearing pegmatite, only fe was found in noticeable concentrations of 0.72 to 0.76 wt. %, which are in agreement with a magmatic origin. also the chemical equilibrium of andalusite with coexisting minerals is an important criterion to prove a magmatic origin. clarke et al. (2005) analysed 108 samples of andalusite-bearing felsic igneous rocks and concluded that biotite coexisting with andalusite has aliv ⁓2.68 ± 0.07 pfu and muscovite is characterised by 0.57 to 4.01 wt. % feo and 0.02 to 2.85 wt. % tio2. as the investigated biotite from the dumortieritebearing pegmatite contains only 1.336 to 1.373 aliv pfu, it seems not to be in equilibrium with andalusite. in contrast, the feo figure 12. in the feotot /(feotot + mgo) vs mgo diagram after zhou (1986), all biotite analyses from dumortierite-bearing pegmatite plot in the field of a crustal source. figure 11. chemical composition of biotite from the dumortierte-bearing pegmatite of mt. moslavačka gora. a) in the ternary (tio2*10)-(feo+mno)-mgo diagram of nachit et al. (2005), all biotite analyses plot in the field of magmatic biotite. b) according to the ternary mgo-feotot-al2o3 diagram of abdel-rahman (1994), the biotite analyses indicate the peraluminous nature of the host rock. g eologia c roatica garašić v. et al.: first occurrence of dumortierite in croatia: its chemical composition and appearance as an igneous mineral in leucogranite-hosted ... 53 (1.31 – 1.48 wt. %) and tio2 (0.56-0.70 wt. %) contents of muscovite fulfil the criteria. besides chemical criteria, textural criteria can also be useful to identify an igneous origin for andalusite (clarke et al., 2005). on the one hand, the single euhedral to subhedral andalusite grains in the dumortierite-bearing pegmatite are comparable in size with the other minerals (biotite, muscovite) present and fit to the s3 textural type of andalusite in felsic igneous rocks (textural classification after clarke et al., 2005). however, no mineral inclusions typical for metamorphic andalusite, such as, for instance, carbonaceous material defining a chiastolite cross, are present. taking into account both chemical and textural criteria, an igneous origin is likely for the andalusite of dumortierite-bearing pegmatite. although the replacement of andalusite by muscovite may take place under magmatic conditions (clarke et al., 2005), the textural relationships with fine-grained muscovite and additional dum ii suggest a replacement at subsolidus hydrothermal conditions in the studied dumortierite-bearing pegmatite. the stability field of magmatic andalusite in a granitic host rock is defined by the water-saturated granite solidus, the andalusite-sillimanite polymorphic transformation reaction and the stability field of muscovite (clarke et al., 2005). among the many factors that favour crystallisation of andalusite from magma (overview in clarke et al., 2005), the following are significant in the studied dumortierite-bearing pegmatite: i) an excess of al2o3 (asi = 1.60), ii) increased boron content (presence of dumortierite) may contribute to lowering of the granite solidus, and iii) the presence of small amounts of transition element solid solution in andalusite (presence of fe3+-rich pinkish cores) may contribute to broadening the andalusite stability field. furthermore, water-saturated melting reactions at low temperature and pressure are known to favour crystallisation of andalusite (clarke et al., 2005). 7.4. relationships of dumortierite-bearing pegmatite and two-mica leucogranite and genesis of the granitic melt the strong similarities in major, minor and trace element contents of dumortierite-bearing pegmatite and the host two-mica leucogranite (fig. 9a and 9b) clearly indicate their common origin. the chemical similarities in addition to the spatial relationship are a strong argument that the pegmatite melt developed by fractional crystallisation during solidification of the two-mica leucogranite. for this reason, it is important to discuss the formation of the two-mica leucogranite to understand the chemical composition of the dumortierite-bearing pegmatite. the two-mica leucogranite is strongly peraluminous (asi = 1.8), enriched in cs, rb, u, k, ta and nb and characterised by a low cao/na2o (0.14) and high rb/ba (16.4) as well as rb/sr (43.3) ratios. the low cao/na2o and high rb/ba and rb/sr ratios reflect a low amount of plagioclase in the source because plagioclase readily incorporates ca, ba and sr, but not rb (harris & inger, 1992). in contrast, micas are rich in k and rb but poor in ca, ba and sr. according to sylvester (1998), pelite-derived melts usually have cao/na2o ratios less than 0.3. this indicates melting of a plagioclase-poor and mica-rich source, represented by mica-rich schists and paragneiss derived from a pelitic protolith. according to sylvester (1998), the al2o3/tio2 ratio of strongly peraluminous granite melts commonly reflects the melting temperature, even though pressure and water addition have to be taken into account. in fact, an increase of the melting temperature leads to increasing breakdown of ti-bearing phases (ilmenite, biotite) and, consequently, to a decrease of the al2o3/ tio2 ratio. the al2o3/tio2 ratio of the investigated two-mica leucogranite is 210 and corresponds to relatively low temperatures and a low degree of melting. this is in accordance with temperatures calculated by balen & broska (2011) for the crystallisation of a two-mica granite with tourmaline nodules from mt. moslavačka gora. they determined zircon and monazite saturation temperatures of ⁓730⁰c and ⁓720⁰c, respectively. on the basis of chemical and isotopic data, garašić et al. (2007) concluded that the two-mica leucogranite from mt. moslavačka gora formed by the melting of continental crust in a collisional environment. as potential field evidence for crustal melting in a collisional environment, balen & broska (2011) described the occurrence of metapelitic xenoliths within the twomica granite. the authors emphasised that the strong muscovite depletion in the metapelitic xenoliths argues for their restitic nature. according to sylvester (1998), strongly peraluminous granitic intrusions occur as a consequence of post-collisional processes in various orogens. the european alps and himalayas are regarded as high pressure collisions characterised by overthickened crust. in this environment, melting is caused by the radioactive decay of k, u and th, and strongly peraluminous granitic melts with high al2o3/tio2 ratios develop at relatively low temperatures (<875⁰c). in contrast, the european variscides and the lachlan fold belt (australia) are defined as high temperature collisions with less crustal thickening (≤ 50 km), where anatexis is related to the upwelling of hot asthenosphere, resulting in hot (≥ 875⁰c) melts having low al2o3/tio2 ratios. even though the al2o3/tio2 ratio in the two-mica leucogranite from mt. moslavačka gora is high and corresponds to low melting temperatures, high pressure metamorphism and an overthickened crust is lacking in the area. therefore, similarities with the genesis of the peraluminous leucogranites of the european alps are highly questionable. as the majority of the strongly peraluminous granites of the european variscides are the result of high temperature melting and are characterised by low al2o3/ tio2 ratios, they also exhibit minor similarities with the two-mica leucogranite from mt. moslavačka gora. taking all arguments into account, it seems that the two-mica leucogranite of mt. moslavačka gora is quite unique and not comparable with the majority of the peraluminous granites from the european alps, himalayas and european variscides. 7.5. genesis of the dumortierite-bearing pegmatite comparing the chemical characteristics of dumortierite-bearing pegmatite and two-mica leucogranite, the asi, the contents of cs, rb, u, k, ta and nb as well as the rb/ba and rb/sr ratios of the pegmatite are higher, whereas the cao/na2o ratio is lower than that of the leucogranite. all these features are compatible with fractional crystallisation of a granitic melt and the formation of a residual melt which subsequently crystallised as pegmatite. the primary mineral assemblage of the pegmatite consists of blue dumortierite i (dum i), andalusite, biotite, muscovite, plagioclase, k-feldspar and quartz. with respect to the presence of magmatic andalusite, crystallisation occured at shallow crustal levels, maybe at 5-6 km depth as for the nearby two-mica granite (balen & broska (2011). g eo lo gi a c ro at ic a geologia croatica 77/154 later circulation of ti-rich hydrothermal fluids led to the partial replacement of primary dum i by secondary purple dum ii enriched in mg and ti. additional dum ii formed at the expense of magmatic andalusite. during the temperature decrease, perthite formed in feldspar and at still lower temperatures, sericite partially replaced, not only feldspars, but also andalusite and both types of dumortierite along grain boundaries and cracks. the last alteration includes the formation of clay minerals at the expense of feldspars. the dumortierite-bearing pegmatite lacks deformation and, therefore, is associated with a late to post-tectonic phase of the continental collision along the sava suture zone. the formation of dumortierite instead of tourmaline in the pegmatite may be explained by the high al2o3 (15.63 wt. %) content and quite low content of iron and magnesium oxides in the melt (fe2o3 = 0.55 wt.%; mgo = 0.06 wt.% in dumortierite-bearing pegmatite). in fact, tourmaline occurs frequently in the twomica granite and the host two-mica leucogranite of mt. moslavačka gora. in the two-mica leucogranites, it is characterised by a chemical zoning and a schorl-foitite composition (garašić et al., 2007). balen & petrinec (2011) recognised differences between tourmaline occurring in nodules within the two-mica granite and disseminated tourmaline in cross-cutting leucogranite dykes. 7.6. classification of dumortierite-bearing pegmatite according to the presented data, the dumortierite-bearing pegmatite from mt. moslavačka gora developed by fractional crystallisation of a granitic melt and based on the modal mineral composition, it is a granitic pegmatite. except for minor amounts of dumortierite and andalusite, no special minerals are observed and there is only slight enrichment of some rare elements (e.g. cs, rb, u, ta and nb). with respect to the most commonly used classification of granitic pegmatite by černy & ercit (2005), the studied dumortierite-bearing pegmatite can be attributed to the abyssal class and ab-bbe subclass, when considering the mineralogical composition only. some elements typical for the lct family are enriched, but even though the li content is not determined, no strong enrichment is indicated by the absence of typical li-rich minerals. however, the abyssal pegmatite class is known to occur in high-grade metamorphic host rocks of upper amphibolite to granulite facies, and frequently originated by anatectic melting (čempirek & novak, 2006). additionally, the ab-bbe subclass is often considered as an indicator for high pressure metamorphic conditions in the country rocks (čempirek & novak, 2006). in contrast, the investigated dumortierite-bearing pegmatite of mt. moslavačka gora developed by magmatic differentiation from a two-mica leucogranite and the presence of magmatic andalusite as well as the data concerning the regional geological evolution argue against a relationship with high pressure metamorphic conditions. for these reasons, it does not represent a typical abyssal pegmatite. alternatively, the classification of granitic pegmatites by wise et al. (2022) can be applied. according to this classification, the studied dumortierite-bearing pegmatite belongs to group 3 pegmatites, because of its strongly peraluminous nature, the mineral composition consisting of quartz, k-feldspar, plagioclase, muscovite, biotite, primary andalusite and a b-mineralization expressed by dumortierite. however, wise et. al (2022) claim that group 3 pegmatites occur in high-grade metamorphic areas and are direct products of the anatexis (dpa) of amphiboliteto granulite-facies metamorphic metapelite, amphibolite, paragneiss and migmatite. in contrast, the dumortierite-bearing pegmatite crystallised from a residual granitic melt (rgm in terms of wise et al., 2022). in summary, it is difficult to classify the dumortierite-bearing pegmatite from mt. moslavačka gora using the existing classification schemes. 7.7. comparison of dumortierite-bearing pegmatite with other dumortierite occurrences worldwide according to the literature mentioned in the introduction, dumortierite is relatively rare, but most frequently found as a minor component in alumina-rich regional metamorphic rocks. additionally, it appears in acidic magmatic rocks, such as granite and granitic pegmatite, and within hydrothermally altered rocks. the rare dumortierite-bearing pegmatite dykes almost all occur in high-grade metamorphic areas, and they are thought to represent products of the anatexis of metapelitic country rocks. for instance, dumortierite-bearing pegmatite dykes are known from several localities in the gföhl unit of the easternmost moldanubian mega unit located in the bohemian massif in austria (fuchs et al., 2005) and the czech republic (cempírek & novak, 2006). they are all characterised by a small thickness, al-rich mineral assemblages and elevated contents of light elements (b, be). their host rocks show a polyphase variscan metamorphic evolution with a granulite facies hp/ht metamorphic overprint (cempírek & novak, 2006). with respect to their mineral composition and the tectonic environment, they are classified as abyssal pegmatites of the ab-bbe subclass, according to the classification of černý & ercit (2005). similar abyssal pegmatite dykes of the ab-bbe subclass were reported from other high-grade metamorphic terranes, for example from antarctica (schüssler & henjes-kunst, 1994; grew, 1998), norway (huijsmans et al., 1982), sri lanka (grew et al., 1995) or india (mahapatra & chakrabarty, 2011). due to the frequent occurrence of dumortierite-bearing abyssal pegmatite dykes in high pressure metamorphic terranes, černý & ercit (2005) suggested that dumortierite-bearing abyssal pegmatites may be a good indicator of hp metamorphism. dumortierite-bearing pegmatite dykes related to a parental granite, as the one described from mt. moslavačka gora, are obviously extremely rare. in the literature, only one example is described that is associated with the szabo bluff granite located in the queen maud mountains in antarctica. however, dumortierite occurs there solely as an alteration product of andalusite (burt & stumf, 1983) and, therefore, this occurrence is not fully comparable. 8. conclusions the investigated pegmatite dyke from mt. moslavačka gora is characterised by a magmatic mineral assemblage of quartz, orthoclase, microcline and albite, and less abundant muscovite, biotite, pinkish andalusite and blue-coloured dumortierite. dumortierite is present as large prismatic grains with a colourless to azure blue pleochroism (dum i) and as smaller bundles of parallel fibrous or acicular crystals with a colourless to redviolet pleochroism (dum ii). both types show differences in their chemical composition. dum i crystals have lower contents of mg (0.033-0.055 pfu) and ti (0.001-0.011 pfu) than dum ii crystals (0.047-0.087 pfu and 0.043-0.064 pfu, respectively). a strong correlation between 3-si and al+ti ( r2 = 0.85) in both dum i and dum ii suggests that ti replaces al in the octahedral position but g eologia c roatica garašić v. et al.: first occurrence of dumortierite in croatia: its chemical composition and appearance as an igneous mineral in leucogranite-hosted ... 55 also together with al, may substitute for si in the tetrahedral position. the presented data confirm that the al/si ratio in natural dumortierite depends not only on pressure conditions but also on additional components, such as fe, mg or ti, in its crystal structure. most probably, an elevated mg content favours a red to violet colour at comparable [fe/(fe+ti)]x100 factors. coarse-grained magmatic muscovite shows na/(na+k) ratios varying between 0.08 and 0.09. biotite chemistry corresponds to annite and indicates not only a magmatic origin but also the peraluminous nature and crustal source of the parental melt of the dumortierite-bearing pegmatite. calculations of the pressure during solidification using the al (tal) content in biotite as a geobarometer yielded pressures of 470 to 495 mpa. these values are not in accordance with the presence of andalusite in the magmatic mineral assemblage. most probably the biotite chemistry is slightly influenced by late hydrothermal fluids. andalusite forms euhedral to subhedral grains which are comparable in size to the magmatic muscovite and biotite. because of these textural criteria and additional chemical criteria defined by clarke et al. (2005), it is part of the magmatic mineral assemblage. dumortierite-bearing pegmatite and the host two-mica leucogranite show strong similarities in major, minor and trace element contents. these chemical similarities, in addition to the spatial relationships, argue for the development of the pegmatite melt by fractional crystallisation during solidification of the twomica leucogranite. the investigated pegmatite is quite unique and not fully comparable with any described dumortierite-bearing pegmatite worldwide. most dumortierite-bearing granitic pegmatites occur in high-grade metamorphic host rocks and are thought to be products of anatectic melting of the country rocks. even if the mineralogical composition of the dumortierite-bearing pegmatite from mt. moslavačka gora allows a classification in the abyssal pegmatite class and the ab-bbe subclass, its formation by fractional crystallisation from a granitic melt is not in accordance with such an interpretation. acknowledgement this work was supported financially by the ministry of science and education, republic of croatia in the scope of the scientific project: „magmatism and mineral deposits of dinaride carst area“, no.195-1953068-3206. references abdel-rahmen, a.f.m. (1994): nature of biotites from alkaline, calc-alkaline and peraluminuous magmas.– journal of petrology, 35, 525–541. alexander, v.d., griffen, d.t. & martin, t.j. (1986): crystal chemistry of some feand ti-poor dumortierites.– american mineralogist, 71, 786–794. barić, lj. (1972): kontaktnometamorfni mramori iz okolice podgarića u moslavačkoj gori (hrvatska) [contact metamorphic marbles from the surrounding area of podgarić in mt. moslavačka gora (croatia) – in croatian].– vii kongres geologa sfrj, 2, 1–28. balen, d. (2007): tourmaline nodules occurrence in moslavačka gora (croatia) granite: a snapshot of magmatic processes.– in: tomljenović, b., balen, d. & vlahović, i. (eds.): 8th workshop on alpine geological studies: abstract volume. croatian geological survey, zagreb, 3–3. balen, d., belak, m., tibljaš, d. & tomašić, n. (2000): the succession of metamorphic paragneisses in mineral assemblage from marble – zorovac creek (moslavačka gora, northern croatia).– in: vlahović, i. & biondić, r. (eds.): proceedings of the 2nd croatian geological congress. institute of geology, zagreb, 93–96. balen, d., schuster, r. & garašić, v. (2001): a new contribution to the geochronology of mt. moslavačka gora (croatia).– in: ádam, a., szarka, l., szendrὅi, j. (eds): pandcardi 2001. ii. abstracts, 2–3. balen, d., schuster, r., garašić, v. & majer, v. (2003): the kamenjača olivine gabbro from moslavačka gora (south tisia, croatia).– rad hrvatske akademije znanosti i umjetnosti, 486, knjiga 27, 57–76. balen, d. & petrinec, z. (2010): complex cretaceous evolution of the moslavačka gora crystalline: different aspects from various types of „foreign“ and „cognate“ enclaves inside granites.– in: horvat, m. (ed)., 4th croatian geological congress, abstracts book. croatian geological survey, zagreb, 135–136. balen, d. & broska, i. (2011): tourmaline nodules – products of devolatilization within the final evolutionary stage of granitic melt?– in: sial, a.n., bettancourt, j.s., de campos. c.p., ferreira, v.o. (eds.): granite-related-ored deposits geological society, london special publications 350, 53–68. doi: 10.1144/ sp350.4 balen, d. & petrinec, z. (2011): contrasting tourmaline types from peraluminous granites: a case study from moslavačka gora (croatia).– miner. petrol. 102, 117–134. doi: 10.1007/s00710-011-0164-8 black, p.m. (1973): dumortierite from karikari peninsula: a first record in new zealand.– mineralogical magazine, 39, 245. doi: 10.1180/minmag.1973.039.302.14 burt, d. & stumf, e. (1983): mineralogical investigation of andalusite-rich pegmatites from szabo bluff, scott glacier area.antarctic journal of the united states, 18, 5, 49–52. choo, c.o. & kim, y. (2003): textural and spectroscopic studies on hydrothermal dumortierite from an al-rich clay deposit, southeastern korea.– mineralogical magazine, 67/4, 799–806. doi: 10.1180/0026461036740136 claringbull, g.f. & hey, m.h. (1958): new data for dumortierite.– mineral. magazine, 31, 901–907. doi: 10.1180/minmag.1958.031.242.02 clarke, d.b., dorais, m., barbarin, b., barker, d., cesare, b., clarke, g., baghdadi, m.e., erdmann, s., förster, h.-j., gaeta, m., gottesmann, b., jamieson, r.a., kontak, d.j., koller, f., gomes, c.l., london, d., morgan vi, g.b., neves, l.j.p.f., pattison, d.r.m., pereira a.j.s.c., pichavant, m., rapela, c.w. renno, a.d., richards, s., roberts, m., rottura, a., saavedra, j., sial a.n., toselli, a.j., ugidos, j.m., uher, p., villaseca, c., visona, d., whitney. d.l., williamson, b. & woodard, h.h. (2005): occurrence and origin of andalusite in peraluminous felsic igneou rocks.– journal of petrology, 46/3, 441–472. cohen, e. (1887): andalusitführende granite.– neues jahrb. min. geol. paleont., 2, 178–180. crnko, j. (1990): osnovna geološka karta republike hrvatske 1:100 000, list kutina l 33-90. [basic geological map of the republic of croatia, scale 1 : 100.000, sheet kutina l33-94 – in croatian].– hrvatski geološki institut (zavod za geologiju) zagreb, 2014. crnko, j. & vragović, m. (1990): osnovna geološka karta republike hrvatske 1:100.000. tumač za list kutina l 33-94. [basic geological map of the republic of croatia, scale 1 : 100.000, interpreter for sheet kutina l33-94 – in croatian].– hrvatski geološki institut (zavod za geologiju) zagreb, 2014. 75 p. čempirek, j. & novak, m. (2006): mineralogy of dumortierite-bearing abyssal pegmatites at starkoč and bestvina, kutna hora crystalline complex.– journal of the czech geological society, 1/3–4, 259–270. černý, p. & ercit, t.s. (2005): the classification of granitic pegmatites revisited.– the canadian mineralogist, 43, 2005–2026. doi: 10.2113/gscanmin.43.6.2005 černý, p., london, d. & novak, m. (2012): granitic pegmatites as reflections of their sources.– elements, 8, 289–294. doi: 10.2113/gselements.8.4.289 deer, w.a., howie, r.a. & zussman, j. (1982): an introduction to the rock-forming minerals, orthosilicates.– longman, 936 p. dokukina, k.a., konilov, a.n., van, k.v. & mints, m.v. (2017): dumortieriteand corundum-bearing quartz-feldspar-mica rocks of the belomorian eclogite province: an example of melting of phengite + quartz.– doklady earth sciences, 477/1, 1353–1357. doi: 10.1134/s1028334x17110204 evans, r.j., fyfe, c.a., groat, l.a. & lam, a.e. (2012): mas nmr measurements and ab initio calculations of the 29si chemical shifts in dumortierite and holtite.– american mineralogist, 97, 329–340. doi: 10.2138/am.2012.3880 evans, r.j. & groat, l.a. (2012): structure and topology of dumortierite and dumortierite-like minerals.– the canadian mineralogist 50/5, 1197–1231. fuchs, y., ertl, a., hughes, j.m., prowatke, s., brandstätter, f. & schuster, r. (2005): dumortierite from the gföhl unit, lower austria: chemistry, structure, and infra-red spectroscopy.– eur. j. mineral. 17, 173–183. doi: 10.1127/0935-1221/2005/0017-0173 garašić, v. (1993): metamorfni uvjeti stijena amfibolitnog facijesa moslavačke gore [metamorphic conditions of rocks of amphibolite facies of mt. moslavačka gora – in croatian].– unpubl. magister thesis, faculty of science, university of zagreb, 171 p. garašić, v., kršinić, a., schuster, r. & vrkljan, m. (2007): leucogranite from srednja rijeka (moslavačka gora, croatia).– in: tomljenović, b., balen, d. & vlahović, i. (eds.): 8th workshop on alpine geological studies: abstract volume. croatian geological survey, zagreb, 21–21. g eo lo gi a c ro at ic a geologia croatica 77/156 golovastikov, n.i. (1965): the crystal structure of dumortierite.– doklady akad. nauk. sssr, 162/6, 1282–1284 (in russian, english trans., sov. phys. doklady), 10, 493–495. gonnard, f. (1881): note sur l'existence d'une espèce minérale nouvelle, la dumortiérite dans le gneiss de beaunan, au-dessus des anciens aqueducs gallo-romains de la vallé de l'izeron (rhone).– bull. soc. minéral. fr., 4, 2–8. grew, e.s. (1998): boron and beryllium minerals in granulite-facies pegmatites and implications of beryllium pegmatites or origin and evolution of the archean napier complex of east antarctica.–memoirs of national institute of polar research, special issue 53, 74–92. grew, e.s., hiroi, y., motoyoshi, y., kondo, y., jayatileke, s.j. m. & marquez, n. (1995): iron-rich kornerupine in sheared pegmatite from the wanni complex, at homagama, sri lanka.– eur. j. mineral., 7, 623–636. doi: 10.1127/ ejm/7/3/0623 groat, l.a., evans, r.j., grew, e.s. & pieczka, a. (2012): the crystal chemistry of asand sb-bearing dumortierite.– the canadian mineralogist, 50, 855–872. doi: 10.3749/canmin.50.4.855 harris, n.b.w. & inger, s. (1992): trace element modelling of pelite-derived granites.– contrib. mineral. petrol., 110, 46–56. doi: 10.1007/bf00310881 henry, d.j., guidotti, c.v. & thomson, j.a. (2005): the ti-saturation surface for low-to medium pressure metapelitic biotites: implications for geothermometry and ti-substitution mechanism.– am. miner., 90/2–3, 316–328. doi: 10.2138/ am.2005.1498 huijsmans, j.p.p., barton, m. & van bergen, m.j. (1982): a pegmatite containing fe-rich grandidierite, ti-rich dumortierite and tourmaline from the precambrian, high-grade metamorphic complex of rogland, s.w. norway.– neues jahrbuch für mineralogie, abhandlungen, 143, 249–261. kišpatić, m. (1887): olivinski gabro iz moslavačke gore (hiperstenit) [olivine gabbro from the mt. moslavačka gora (hyperstenite) – in croatian].– rad jazu, 95, 24– 51. khalegl, f. (2019): occurrence, mineral chemistry and origin of dumortierite in ali javad porphyry cu-au deposit, sheivar dagh alteration system, nw iran.– periodico di mineralogia, 88, 131–145. korolija, b. & crnko, j. (1985): osnovna geološka karta sfrj 1 : 100 000, list bjelovar, l 33-82 [basic geological map of sfr yugoslavia, scale 1 : 100 000, sheet bjelovar, l 33-82 – in croatian].– hrvatski geološki institut (zavod za geologiju), savezni geološki zavod beograd, 1985. korsakov, a.v., rezvukhina, o.v., rezvukhin, i., greshnyakov, e.d. & shur, v.ya. (2019): dumortierite and tourmaline from the barchi-kol diamond-bearing kyanite gneisses (kokchetav massif): a raman spectroscopic study and petrological implications.– j. raman sectrosc., 51, 1839–1848. doi: 10.1002/ jrs.5699 mahapatra, s. & chakrabarty, a. (2011): dumortierite from susunia hill, bankura district, west bengal, india.– current science, 100,3 299–301. monier, g., mergoil-daniel, j. & la bernardie, h. (1984): generations successives de muscovites et feldspaths potassiques dans les leucogranite du massif de millevaches (massif central francais).– bulletin de mineralogie, 107, 55–68. moore, p.b. & araki, t. (1978): dumortierite si3b-[al6,75□0,25o17,25 (oh)0,75]: a detailed structure analysis.– n. jahrb. mineral. abh. 132, 231–241. nachit, h., ibhi, a., abia, e.h. & ohoud, m.b. (2005): discrimination between primary magmatic biotites, reequilibrated biotites and neoformed biotites.– comptes rendus geoscience., 337, 1415–1420. palinkaš, a.l., balogh, k., strmić, s., pamić, j. & bermanec, v. (2000): ar/ar dating and fluid inlusion study of muscovite, from the pegmatite of srednja rijeka, within granitoids of moslavačka gora mt., north croatia.– in: tomljenović, b., balen, d. & saftić, b. (eds): pancardi 2000, special issue, vijesti hrvatskog geološkog društva, 37, 95–96. pamić, j. (1987): granites and associated monzodiorites and gabbros from kamenac creek on mt. moslavačka gora (northern croatia, yugoslavia).– rad jazu, 431/22, 179–199. pamić, j. (1990): alpine granites, migmatites and metamorphic rocks from mt. moslavačka gora and the surrounding basement of the pannonian basin (northern croatia, yugoslavia).– rad jugoslavenske akademije znanosti i umjetnosti, 10, 7–121. pamić, j. (1998): crystalline basement of the south pannonian basin based on surface and subsurface data.– nafta, 49, 371–390. pamić, j. & jurković, i. (2002): paleozoic tectonostratigraphic units of the northwest and central dinarides and the adjoining south tisia.– international journal of earth sciences (geologische rundschau), 91, 787–798. pattison, d.r.m. (2001): instability of al2sio5 „tripple-point“ assemblages in muscovite+biotite+quartz-bearing metapelites, with implications.american mineralogist, 86, 1414–1422. pieczka, a., grew, e.s., groat, l.a. & evans, r.j. (2011): holtite and dumortierite from the szklary pegmatite, lower silesia, poland.– mineralogical magazine, 75/2, 303–315. doi: 10.1180/minmag.2011.075.2.303 puxeddu, m. (2022): interaction of b-rich supercritical magmatic fluids with granite: first report of dumortierite in a geothermal field, larderello, italy.– south florida journal of development, 3/3, 3162–3169. doi: 10.46932/sfjdv3n3-009 samadi, r., torabi, g., kawabata, h. & miller, k.n. (2021): biotite as a petrogenetic discriminator: chemical insights from igneous, meta-igneous and meta-sedimentary rocks in iran.– lithos, 386–387, 106016. doi: 10.1016/j.lithos.2021.106016 schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpinecarpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss j geosci, 101, 139–183. doi: 10.1007/s00015-008-1247-3 schüssler, u. & henjes-kunst, f. (1994): petrographical and geochronological investigations on a garnet-tourmaline pegmatite from ringgold knoll, oates coast, antarctica.– chem. erde, 54, 297–318. starijaš, b., gerdes, a., balen, d., tibljaš, d. & finger, f. (2010): the moslavačka gora crystalline massif in croatia: a creataceous heat dome within remnant ordovician granitoid crust.–swiss j. geosc, 103, 61–82. doi: 10.1007/ s00015-010-0007-3 sylvester, p.j. (1998): post-collisional strongly peraluminous granites.– lithos, 45, 29–44. doi: 10.1016/s0024-4937(98)00024-3 taner, m.f. & martin, r.f. (1993): significance of dumortierite in an aluminosilicate-rich alteration zone, louvicourt, quebec.– canadian mineralogist, 31, 137–146. tang, p., chen, y., tang, j., wang, y., zheng, w., leng, y., lin, b. & wu, c. (2019): advances in research of mineral chemistry of magmatic and hydrothermal biotites.– acta geologica sinica (english edition), 2019, 93/6, 1947–1966. doi: 10.1111/1755-6724.14395 tućan, f. (1904): pegmatit u kristaliničnom kamenju moslavačke gore [pegmatite in crystalline rocks of mt. moslavačka gora – in croatian].– rad jazu, 159, 166–208. tućan, f. (1953): nov prinos poznavanju kristalastih stijena moslavačke gore [new contribution to understanding of crystalline rocks of mt. moslavačka gora – in croatian].– jazu, spomenica miše kišpatića, 39–69. uchida, e., endo, s. & makino, m. (2007): relationship between solidification depth of granitic rocks and formation of hydrothermal ore deposits.– resource geology, 57/1, 47–56. doi: 10.1111/j.1751-3928.2006.00004.x visser, d. & senior, a. (1991): mg-rich dumortierite in cordierite-orthoamphibolebearing rocks from the high-grade bamble sector, south norway.– mineralogical magazine, 55, 563–577. doi: 10.1180/minmag.1991.055.381.09 vrana, s., štedra, v. & nahodilova, r. (2009): geochemistry and petrology of high-pressure kyanite-garnet-albite-k-feldspar felsic gneisses and granulites from the kutna hora complex, bohemian massif.– journal of geosciences, 54, 159–179. doi: 10.3190/jgeosci.045 werding, g. & schreyer, w. (1983): synthesis, crystal chemistry, and preliminary stability of dumortierite in the system sio2-al2o3-b2o3-h2o.– fortschr. min. 6/1, 219–220. werding, g. & schreyer, w. (1990): synthetic dumortierite: its ptx-dependent compositional variations in the system al2o3-b2o3-sio2-h2o.– contrib. mineral. petrol., 105, 11–24. doi: 10.1007/bf00320963 willner, a.p. & schreyer, w. (1991): a dumortierite-topaz-white mica fels from the peraluminous metamorphic suite of bushmanland (south africa).– n. jb. miner. mh., 1991, 5, 223–240. wise, m.a., müller, a. & simmons, w.b. (2022): a proposed new mineralogical classification system for granitic pegmatites.– the canadian mineralogist, 60, 229–248. doi: 10.3749/canmin.1800006 zhou, z.x. (1986): the origin of intrusive mass in fengshandong, hubei province.– acta petrol. sin., 2/1, 59–70. 2023 | 76/1 | 47–56 | 10 figs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the žune ore deposit in bosnia and herzegovina is part of the ljubija ore field and is located about 2.5 km west of the town of ljubija (fig. 1). the ljubija ore field is situated within the upper palaeozoic sequence of the sana-una palaeozoic complex of the inner dinarides. in the wider area of ljubija, there are smaller and larger bodies of mineralization (metres to hundreds of metres in size), mainly involving fe carbonates with subordinate fe, pb, zn and cu sulphides that usually occur in a later phase, as well as slightly younger barite and fluorite mineralization (palinkaš et al., 2016). of the numerous occurrences of barite in the region, the most interesting (from an economic perspective), is the phenomenon with fluorite in the donja ljubija zone, on the dolinacžune-dobrića do line (čičić, 1976). the žune barite-fluorite deposit is a vein-type deposit situated in the upper palaeozoic dolostone and close to the contact with lower triassic schists and sandstones. in the žune area, barite was exploited by the surface mining method until 1961. total reserves were 10.000 t, containing 82-98 % of barite, 0.3-1.3 % of sio2, 0.4-1.5 % of al2o3, 0.1-0.4 % of fe2o3 and 0.01-6.02 % of cao. exploitation ceased when the barite to fluorite ratio became so unfavourable that the economic separation of barite and fluorite could no longer be carried out with the available technology (jeremić, 1958). the aim of this study is to explore the žune ore deposit in more detail and to define the depth of the ore body and spatial distribution of the mineralization. therefore, detailed geological mapping of the žune mining cut and surrounding area was carried out indicating that the ore body is laid out vertically with an east-west extension, while a transverse fault with an approximate north-south direction divides the body into the eastern and west the žune ba-f epithermal deposit: geophysical characterization and exploration perspective jasna orešković1,*, aleksej milošević2, saša kolar1 and sibila borojević šoštarić1 1 university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, hr-10000 zagreb, croatia; (*corresponding author: jasna.oreskovic@rgn.unizg.hr) 2 university of banja luka, faculty of mining, bulevar vojvode petra bojovića 1a, 78000 banja luka, bosnia and herzegovina doi: 10.4154/gc.2023.04 abstract the žune barite-fluorite ore body in northwestern bosnia and herzegovina has been explored using geophysical methods to determine the spatial distribution of the mineralization. the mineralization occurs in a 50 m long ese-wnw fault zone in the form of a subvertical barite-fluorite vein, transforming to strings of tiny barite veins and impregnations at the immediate contact with the host dolostone. the geophysical research included 2d electrical resistivity tomography (ert) measured along four profiles. in addition to resistivity inversion results, forward modelling has been performed along two profiles transecting the mining cut. prior to surface geophysical measurements, detailed geological field mapping of the ore body and host rocks was undertaken. the main faults defined by geological field mapping, have been confirmed with geophysical results as well as the contact of the host dolostone with lower to middle triassic sandstones. the contact is defined to the south of the deposit. however, based on the resistivity model, the position of the contact is about ten metres further south. the forward modelling results revealed that the barite-fluorite vein in the area of the mining cut is limited to a depth of about 10 m and the length is about 70 m. the vein is up to 5 m thick and almost 10 m wide. there is no indication for barite-fluorite mineralization in the area south of the studied mining cut with predominant triassic sandstones, while anomalies that may be associated with ore bodies are present in the northern and northeastern parts, composed of carboniferous dolostone. ern parts (fig. 2). the possibility of a coherent deposit with several ore bodies, apart from the carboniferous dolomites as host rocks, is indicated by the regional fault of the east-west direction. several long faults of mostly dinaric extension intersect the deposits and separate them to about ten blocks. exploration of the žune barite-fluorite mineral deposit is challenging due to the complex structural setting driven by subvertical faults and a number of joint-systems (borojević šoštarić et al., 2022). therefore, geophysical methods can help identify areas of a blind ore mineralization since mineral deposits usually have physical properties that contrast with their host rocks (e.g. bishop & emerson, 1999; meju, 2002). depending on the physical properties of rocks associated with the mineral deposit and in contrast with surrounding material, different geophysical methods can be applied (ford et al., 2007). electrical resistivity is a physical property of rocks that generally shows a contrast between mineralized units and surrounding rocks (evrard et al., 2018). the current study focuses on the evaluation of a baritefluorite deposit where barite veins and the barite-fluorite ore are hosted in layered and brecciated dolostone. the barite-fluorite deposits resistivities are expected to be high (e.g. akpan et al., 2014; batista-rodríguez & pérez-flores, 2021) compared to the surrounding rocks. this makes barite veins detectable by electrical and electromagnetic methods. the density of barite is also high, therefore the gravity method can be applied utilizing the high density contrast that exists between barite, especially massive ore bodies, and most of the host rocks (barnes et al., 1982). in the present case, the gravity method was not applied due to the small size of the ore bodies and very steep flanks of the mining cut. therefore, electrical resistivity tomography (ert) has been applied to characterize the ore deposit. two-dimensional article history: manuscript received december 27, 2021 revised manuscript accepted january 23, 2023 available online february 23, 2023 keywords: barite-fluorite deposit, electrical resistivity tomography (ert), inversion, forward modelling g eo lo gi a c ro at ic a geologia croatica 76/148 models of the resistivity distribution in the study area are obtained and correlated to geological mapping data. finally, the results on the dimensions and characterization of the žune deposit and the possible presence of barite deposits north and south of the žune mining cut are discussed. 2. geological setting 2.1. regional setting the dinaric palaeozoic basement units with corresponding triassic cover are overthrust onto the adriatic carbonate platform in a distinct nw-se trending zone extending for almost 700 km and separating the external from the internal dinarides units (pamić et al., 1998; fig. 1a, b). at the north-westernmost and central part of the dinaride basement outcrops in a zone <100 km in cross-section, widening toward the southeast to almost 400 km in cross section. the palaeozoic units vary in age from the ordovician (mid-bosnian schists mts.; hrvatović, 2006) to the late permian and permo-triassic, as well as the degree of metamorphism that generally increases from the northwesternmost, non-metamorphosed part, toward the central part of the dinarides showing greenschist to lower amphibolite facies metamorphism (borojević šoštarić et al., 2009 and references therein). figure 1. (a) geological map of the sana-una complex showing locations of the iron ore deposits and barite occurrences (modified after grubić et al., 2015) and (b) geological map of the main tectonic units in the northwestern and central dinarides with the location of the žune ore body (modified after pamić (1993), pamić et al. (1998), schmid et al. (1998), willingshofer (2000) and tomljenović (2002)). g eologia c roatica orešković et al.: the žune ba-f epithermal deposit: geophysical characterization and exploration perspective 49 the sana-una palaeozoic complex is located to the east of the una river in the north-western part of bosnia and herzegovi na. to the northwest, the sana-una palaeozoic complex is separated from its continuation, the trgovska gora palaeozoic region in croatia by the una river and surrounded by the lower to middle triassic terrigenous-carbonate strata. 2.2. local geological setting a wider area of the žune deposit displays two main lithostratigraphic units (fig. 2): (1) the carboniferous flysch with olistostromes (the olistostrome member of grubić et al., 2015) is a deep-sea unit of variable thickness (between 100 to 300 m), composed of flysch matrix embedding carbonate olistolith segments and blocks of decametres to a hundredmetres in size. fossiliferous olistoliths are of devonian, early and later carboniferous ages (jurić, 1971), setting the age of the unit as middle to upper carboniferous (grubić & cvijić, 2003). this agrees with recent palaeontological data according to which the carbonate blocks are of bashkirian age (milošević et al., 2021). carbonate olistoliths are composed of black micrites, dark grey organogenic and fossiliferous sparites, dolomitic limestones and dolostone. they are often metasomatised and mineralized containing siderite, ankeri te and iron-rich carbonate (garašić & jurković, 2012; strmić-palinkaš et al., 2009; palinkaš et al., 2016). (2) lower to middle triassic terrigenous formations are represented by carbonate clastic development with intercalations of terrigenous, micaceous limestone, siltstone and sandstone, and in the wider area colourful marls, peloid rocks and breccia (grubić & protić, 2003). mineralization the žune barite-fluorite ore body is embedded in porous tectonized dolostone of the carboniferous olistostrome member and close to the contact with the lower to middle triassic terrigenous carbonates (fig. 3), in the ese-wnw trending variscan fault zone. thin-bedded host dolostone occupies the central part of the deposit and the lower parts of the mining cut (figs. 3 and 4). the thickness of the dolostone layers ranges from 2 to 5 cm, sometimes up to 20 cm. the stratification is well-defined and dips to the east-southeast. the host dolostone is subvertical with a steep slope to the north-northeast, thickness varies from 3 to 20 m along exposed length of 50 m. a 36.5-metre-long exploration drift leaves the ore body after 20.5 metres (fig. 3). the variscan fault zone likely functioned as a pathway for the circulation of hydrothermal fluids, acting as the main control factor for barite-fluorite mineralization. the mineralization is vein-type, composed of the main barite-fluorite vein (3 to 9 m thick), emplaced sub vertically with an east-west extension. the barite to fluorite ratio is 80:20. the contact zone between dolostone and mineralization consists of metasomatically recrystallized host dolostone, quartz associated with accessory minerals and pyrite with strings of tiny barite veins and impregnations and is mostly brecciated. accessory minerals provide evidence for pre-mineralization conditions with temperatures exceeding 300°c (borojević šoštarić et al., 2022). the central part of the vein consists of pure barite, some fluorite and accessory sulfide minerals (jeremić, 1958). syn-mineralization conditions from nacl-cacl2-h2o fluids under temperature of 100–310 °c were determined by palinkaš et al. (2016). furthermore, based on the fluorite-hosted fluid inclusions, the authors reported evidence for a low-pressure boiling event under epithermal conditions. hydrothermal fluids were interpreted as being a mixture of high-temperature-high-salinity permian evaporitic sea water, diluted by low-temperature-low-salinity marine or meteoric waters. at the lowest level, the ore body appears to narrow, while it broadens toward the higher levels, retaining similar structural figure 2. location map of the žune survey area with the positions of ert profiles and the mining cut. the main geological units and faults within exploration area are displayed. g eo lo gi a c ro at ic a geologia croatica 76/150 features (jurić, 1971). the upper part of the ore body is enriched with limonite of supergene origin, related to oxidation of minor sulfide mineralization associated with the barite-f luorite (jeremić, 1958). dolostone from both sides of the main barite-fluorite vein contains irregular barite veinlets imprinted in various fracture directions (stockwork to impregnation type), usually across the bedding or isolated barite lenses (figs. 3 and 4). barite lenses are 20 x 30 cm in size and can sometimes be traced for as far as 10 m. the contact with the surrounding dolostone is usually sharp. in the southern part of the deposit, lower to middle triassic formations are exposed and consist mainly of intercalations of reddish and purple quartz sandstones with sericite and shaly clays. the contact with the dolostone is tectonic. the central part of the exploration drift is covered with a 2 m thick barite embankment consisting of variable-size dolomite, barite and barite with fluorite blocks in clayey-sandy detritus, representing a remnant of previous mining activities (fig. 3). 3. methodology 3.1. geophysical data acquisition geophysical data acquisition was carried out covering the wider area of the abandoned mining cut in žune (fig. 2). electrical resistivity tomography (ert), a surface geophysical method was used to map the prospective baritefluorite area. the ert technique is used to image both vertical and lateral variations of resistivity along the measured line. as a result, a pseudosection of apparent resistivities is plotted. four profiles were set up at the žune survey area and the data were collected using an abem sas 1000 resistivity meter and the es 10-64 selector. the first ert line was a 760 m long profile (ert-1 in fig. 2) that covered figure 3. a cross–section of the žune barite–fluorite body along the line ab in a ssw-nne direction. location of the cross-section is marked on the map in fig. 2 (modified after jeremić, 1958). figure 4. a cross – section of the žune ore body along the southern side of the mining cut. g eologia c roatica orešković et al.: the žune ba-f epithermal deposit: geophysical characterization and exploration perspective 51 the barite-fluorite outcrop in the direction of its longer axes. to cover a larger prospective area, two additional 400 m long ert lines almost parallel to ert-1 (ert-2 and ert-3 in fig. 2), and one diagonal line were set up (ert-4 in fig. 2). the wenner electrode configuration with a unit electrode spacing of 10 m was used for the electrical resistivity measurements along lines ert1, ert-3 and ert-4, while an electrode spacing of 5 m was used along the line ert-2. thus, the investigation depth along the longest ert-1 line is about 135 m and other profiles reach about 70 m at the deepest part. the measured 2d apparent resistivity sections were interpreted using inversion and forward modelling based on the method published by loke & barker (1996). 3.2. inversion and forward modelling the electrical resistivity tomography (ert) measurements give 2d apparent resistivity pseudosections, and to obtain true resistivity models that reflect the subsurface geology, an inversion of the data is required. the recorded apparent resistivity data along four ert profiles were interpreted using inversion as well as forward modelling. automatic inversion of observed data was used to rapidly determine the best resistivity model that fits the measured field data. the boundaries in the inverse model are difficult to define since the transition zone from low to high resistivity is wide, therefore forward modelling was applied in order to interpret the inversion results more reliably. during modelling, the apparent resistivity pseudosection is calculated for an a priori defined 2d subsurface model. the advantage of forward modelling is that the model can be lithologically constrained by data from other sources (geological data or results of other geophysical surveys). it also provides the opportunity to test several possible models with different depths of boundaries or lateral extent of structures. during inversion, an homogenous resistivity 2d model consisting of rectangular blocks was used. the number of blocks and their distribution is set according to the distribution of observed data points in the pseudosection. the inversion is performed using a non-linear smoothness-constrained least-squares optimisation technique (de groothedlin & constable, 1990; loke et al., 2003). the convergence criterion was the relative change in the rms error between two iterations. the forward modelling simulation calculates the apparent resistivity pseudosection for a userdefined 2d subsurface model. the results based on this model are inverted and then compared to the results of observed data. this involves dividing the subsurface into a number of blocks using a rectangular mesh, with each block characterized by its resistivity. the size of the blocks, i.e. how finely defined the mesh is, depends on the complexity of the geological structure being modelled. in 2d forward modelling the finitedifference method (dey & morrison, 1979) was used to determine the potential at each node of the mesh. 4. geophysical models 4.1. inversion of ert data the geophysical survey of the žune barite-fluorite deposit started with the longest profile located through the abandoned mining cut (ert-1 in fig. 2) and was followed by three additional profiles of half the length. the measured data along four profiles are interpreted using inversion (figs. 5-7). during inversion of the measured data, least-square equations are solved using a standard gauss-newton method. a relative change in the rms error of 0.1 was used to test the convergence of calculated apparent resistivity data. the models are displayed with the maximum depth in the central part corresponding to the depth of investigation with the largest electrode spacing (edwards, 1977). the final inverted resistivity model along ert-1 was obtained after five iterations with an rms error of 3.6 % (fig. 5). the interpreted depth is about 100 m in the central part of the profile. the obtained model provides information about the subsurface in the mining cut and in the surrounding area. the most prominent feature of the resulting model is high resistivity (> 4000 ωm) in the central part of the profile exactly where the mining cut is located. the high resistivity structure extends to a depth of 5-10 m. at the beginning of the profile, the resistivity is lower (about 200 ωm), as well as in the second part of the profile at a very shallow depth (to about 10 m). in the deeper parts of the profile the resistivities are rather high (between 1000 and 2000 ωm), with the greatest values at distances between 250 and 320 m. these resistivities most probably originate from carbonate rocks while lower resistivities in the first 180 m of the profile could be associated with sandstones and the near surface resistivities originate from soil and clay. according to the results of geological mapping presented in figure 2, the žune mining cut is bordered by two faults at about 335 m (f1) and 430 m (f2) profile distance. the western fault can be recognized in the inverted model as a sharp resistivity transition near 340 m, while the position of the eastern one is not so clearly visible. profiles ert-2 and ert-3 are about half the length of profile ert-1 and are nearly parallel to it (fig. 6). the ert-2 is located 40 to 20 m north of the profile ert-1, and ert-3 is south of it. unit electrode spacing on the ert-2 profile was 5 m, since the electrode spacing is one of the factors affecting the resolution of observed data, besides array configuration and signal-to-noise ratio (cardarelli & de donno, 2019). smaller spacing has been expected to produce better resolution. the inverted model figure 5. 2d inversion along profile ert-1 stretching in the direction of the longer axes of the mining cut. the intersection with profile ert-4 is marked by an arrow, and location of the mining cut is indicated. positions of the major faults defined within location map in fig. 2 are indicated with red line at the surface. g eo lo gi a c ro at ic a geologia croatica 76/152 of the ert-2 profile was obtained after five iterations and the rms error is 3.0% (fig. 6a). the ert-2 shows the highest resistivities in the survey area. the high resistivity anomaly stretches approximately from 110 m to 170 m and between 230 and 250 m. the depth of the anomaly can be estimated to be about 5-10 m. a minor high resistivity anomaly is observed at a distance of 200 m close to the surface. however, the inversion results of profile ert-3 show that the resistivities south of ert-1 are generally low, especially near the surface (to 5 m depth) as well as at the western part of the profile at greater depths (fig. 6b). high resistivity can be observed only at the beginning of the profile, between 50 and 75 m, at shallow depths. profile ert-4 is 370 m long and extends diagonally to the other three profiles in an ese-wnw direction, and intersects the mining cut transversely at the distance of 110 to 130 m. at the beginning of the profile, the resistivity is about 400 ωm until the distance of 70 m (fig. 7). this is significantly lower than the resistivity along the rest of the profile. from a distance of 70 m, the resistivity increases sharply and reaches about 2000 ωm. this is also expected according to the location map in figure 2, since the sandstones in the southern part of the žune deposit are in contact with tectonized dolostone. the 3d subsurface resistivity image by combining the inverted ert models of two profiles (ert-2 and ert-4) is presented in fig. 8. the models show that the highest resistivity is found in the central and western part of profile ert-2, while profile ert-4 crosses this anomaly at its eastern edge (figs. 6 and 8). the highest resistivity could be associated with a barite or barite-fluorite deposit, although high resistivity values are also figure 6. inverted 2d resistivity models nearly parallel to ert-1: (a) ert-2 and (b) ert-3. the intersection with the profile ert-4 which is laid diagonally is indicated by an arrow. figure 7. inverted 2d resistivity model along profile ert-4 which intersects transversely the mining cut. intersections with the other three profiles are indicated with arrows. g eologia c roatica orešković et al.: the žune ba-f epithermal deposit: geophysical characterization and exploration perspective 53 expected for dolomites. the eastern part of the exploration area in figure 2 is poorly explored, but there is evidence for the presence of an ore body based on several excavated barite veins. profiles ert-2 and ert-4 in their easternmost parts include this area, but resistivities are rather low and do not indicate the presence of a major barite or barite-fluorite vein in the eastern part. also, there are no anomalies south of the mining cut that could be associated with a barite ore body. 4.2. forward modelling results in the electrical resistivity tomography method, the problem of ambiguity is present similar to onedimensional resistivity methods, but it has a more complicated 2d character. the ambiguity manifests in the fact that there may be many correct geoelectrical models that fit within the accepted rms error limits. in addition, ert survey data are affected by structures located some distance from the survey line. thus, 2d inverted models include spurious effects due to resistivity changes perpendicular to the surveyed profile (cardarelli & de donno, 2019). only in the case where the geological structure is uncomplicated and can be approximated with a 2d model, can an interpreted resistivity section be related to a structure present directly beneath the survey line (bania & ćwiklik, 2013). furthermore, the inverted model has rather wide transitions between high and low resistivities and the boundary is not easy to define. therefore, the inverted models and interpretation results were verified by forward modelling along two profiles, ert1 and ert4 (figs. 9 and 10) that provide a more distinctive picture. in the current study, the geometry of the main structures in the initial models was defined according to the ert inversion results and, where available, data from detailed geological field mapping. the electrode arrays and unit electrode spacing were the same as in the field layout, but topography was not considered. the response (apparent resistivity), for the defined model is calculated using the finite-difference method, and the results are compared to the ert inversion results. in addition to the geometry, resistivities in the model need to be defined. since no laboratory or borehole resistivity measurements were available, the models are based on inversion results and resistivities of the main lithologies published in the literature (schön, 2011; telford et al., 1990). the resistivities for the same rock type have a wide range of values, sometimes over several orders of magnitude. for example, the resistivity range for sandstones (10 to 104 ωm) and dolomites (102 to 7·104 ωm) overlap but sandstones tend to have generally lower resistivity (schön, 2011; ward, 1990). however, the resistivity of rocks depends not only on lithology, but also on rock conditions (degree of fracturing) and fluid content. the resistivities of minerals are more specific, and in ba-f deposits measured resistivity will depend on the barite and fluorite content. both barite and fluorite as minerals are characterized by high resistivity (1.2·107 ωm for barite and 7.7·1013 ωm for fluorite; schön 2011). in the present study, the žune barite-fluorite ore body is imprinted in porous dolostone and barite occurs as pure barite accompanied with fluorite in the central part and porous barite in the ne part of the deposit. fluorite also occurs in lenses or as impregnations within barite veins and dolostone. the deposit is clearly visible on both profiles (ert-1 and ert-4) as a shallow high resistivity anomaly and in resistivity models it is defined with 5·103 ωm. along profile ert-1, the main features are a thin body of high resistivity at shallow depths (yellow in fig. 9) and a high resistivity block to a depth of about 50 m. 2d modelling of the resistivity data confirmed that the anomaly at shallow depth is due to the presence of a 5 m thick block of high resistivity. a greater thickness is unlikely because the inversion results of the block model with a thickness greater than 5 m yield an anomaly that is not consistent with the inversion results of the observed data. the lower resistivity of this block results in a less pronounced anoma ly than the measured one (fig. 9c). the depth to the upper base of the block is about 5 m, since a shallower or deeper structure cannot produce an anomaly that fits the ert inversion results. according to the location, it belongs to a barite-fluorite deposit within the mining cut. the length of the deposit is about 70 m. this structure is also observed on profile ert-4, which extends diagonally to ert-1 (fig. 10). a small anomaly of high resistivi ty figure 8. subsurface resistivity distribution on profiles ert-2 and ert-4 displayed in 3d. the hatch pattern marks the position of the mining cut. g eo lo gi a c ro at ic a geologia croatica 76/154 is interpreted as a block at a distance of 140 to 150 m at a very shallow depth (up to 7 m). the origin of this high resistivity is the same as on ert-1, but the geophysical signature is slightly different due to the orientation of the profile with respect to the ore deposit. according to the forward resistivity model of profile ert-1, the deeper high resistivity anomaly (distance 335 380 m) can be associated with a structure at about 20 m depth (fig. 9), which is probably massive dolostone. the thickness is between 40 60 m. when a smaller resistivity is defined between two blocks of higher resistivity that can be associated with a fault zone (distance 320 350 m in fig. 9b), very good agreement with the observed data is obtained. a zone wider than 30 m is unlikely. the contact between lower resistivity rocks at the beginning of the profile (probably sandstones) and higher resistivity rocks is defined at a distance of about 160 m (fig. 9a and b). forward modelling results indicate that the contact is sharp, as a gradual change between higher and lower resistivities results in a weaker match (fig. 9c). figure 9. 2d forward modelling along profile ert-1. the synthetic resistivity models are shown on the left and calculated resistivity pseudosections are on the right. the inverted resistivity model of measured data is at the top. figure 10. 2d forward modelling along profile ert-4. resistivity models are on the left and inversion of calculated resistivity pseudosections on the right. the inverted resistivity model of measured data is at the top. g eologia c roatica orešković et al.: the žune ba-f epithermal deposit: geophysical characterization and exploration perspective 55 the initial resistivity model along the profile ert-4 (fig. 10a) was constructed according to the inversion results and previous investigations presented in fig. 2, showing the main geological units and faults within the study area. the contact between the lower to middle triassic sandstones and the dolostone is defined by the f3 fault at the southern part of the deposit (fig. 2). profile ert-4 intersects this contact, and therefore lower resistivities are defined in the first part of the model (left in fig. 10) to about 100 m. from 100 m to the end of the profile higher resistivities are expected, and a sharp contact between sandstones and dolostone is defined. the main features of the inverted model (fig. 7 and top of fig. 10) are a high resistivity anomaly near the surface at a distance of about 140 m, and a deeper anomaly at a distance of 210 to 250 m. therefore, a shallow, small block of high resistivity was defined at a profile distance of 140-150 m, corresponding to the position of the mining cut and the barite-fluorite deposit. a deeper block of higher resistivity was defined at a distance of 190 to 250 m. a calculated pseudosection based on the initial model shows a similar resistivity distribution as the observed one in the shallow part, and in the deeper part from a distance of about 150 m (fig. 10a). however, the anomaly present in the inverted model of observed data between 50 and 100 m is not evident. therefore, a higher resistivity was introduced down to a depth of 40 m, which required a larger width of the central block (fig. 10b). finally, the most probable model (fig. 10c) is similar to model (b) but includes a greater thickness of a surface low resistivity layer and consequently a greater thickness of the body at the location of the mining cut. a smaller thickness of the central block is possible which extends over a distance of 190 m to 270 m. the contact could be defined at a distance of about 70 m corresponding to f1 in figure 2, while according to the geological map it is located at a profile distance of 100 m (f3 in figure 2). 5. conclusions the wider area of the žune barite-fluorite ore body was investigated using an electrical resistivity tomography method to characterize the ore body and to identify possible new deposits. four ert profiles were measured to obtain the resistivity distribution in the subsurface. ert forward modelling was used to create more accurate resistivity models than those obtained by automatic inversion. interpretation of the ert data confirmed that the mineralization occurs in an ese-wnw fault zone in the form of a subvertical barite-fluorite vein that is 50 to 70 m long. a strong resistivity anomaly associated with the main barite-fluorite vein is only visible on the longest profile ert-1, which extends along the direction of the žune ore body, and on profile ert-4 which is diagonal to the mining cut. modelling results indicate that the main barite-fluorite vein is located at a depth of 5 to 10 metres and is approximately 70 m long. the thickness of the vein is up to 5 m. based on the forward modelling along profile ert-4, the width of the vein is almost 10 m. according to the location of the most prominent shallow anomaly, the results confirmed the association of the main vein with shallow mineralization. the main faults, which extend in a northeast-southwest direction, have been confirmed on profiles ert-1, ert-2 and ert-4 but are also recognized on profile ert-3. the contact of the host dolostone with lower to middle triassic sandstones, defined in the southern part of the deposit (figs. 2 and 3), has been proved with profile ert-4. however, based on the resistivity model, the position of the contact is about ten metres further south. there is no evidence of barite-fluorite mineralization south of the mining cut, in the area with predominant triassic sandstones. anomalies that can be associated with ore bodies are present in the northern and northeastern part, composed of carboniferous dolostone. profiles ert-2 and ert-4 show high resistivity anomalies, and the major one is located to the north of the mining cut. in the eastern part, the anomalies are less pronounced. their cause could be isolated barite lenses and the presumed occurrences in the form of stockworks and impregnation veins, which show a lower intensity of anomalies than a massive barite-fluorite ore body. since barite veins are hosted in dolostone that is also characterized by high resistivity values, the existence of a high resistivity anomaly cannot provide complete information about the ore body. therefore, exploratory drilling is necessary to ascertain results of geophysical exploration. acknowledgement this work has been financially supported by eit rawmaterials project no. 17051 invest rm: multifactor model for investments in the raw material sector, a part of the horizon 2020 program. we would like to thank the invest rm team (https://investrm.eu/) for continuous fieldwork support, helpful advice, and discussion. a special thanks to colleagues from the mining institute prijedor supervised by director dragoja lajić for their assistance during the geophysical field survey. references akpan, a.e., ebong, d.e., ekwok, s.e. & joseph, s. (2014): geophysical and geological studies of the spread and industrial quality of okurike barite deposit.– am. j. environ. sci., 10/6, 566–574. doi: 10.3844/ajessp.2014. bania, g. & ćwiklik, m. (2013): 2d electrical resistivity tomography interpretation ambiguity – example of field studies supported with analogue and numerical modelling.– geology geophysics & environment, 39/4, 331–339. doi: 10.7494/ geol.2013.39.4.331 barnes, d.f., mayfield, c.f., morin, r.l. & brynn s. (1982): gravity measurements useful in the preliminary evaluation of the nimiuktuk barite deposit, alaska.– econ. geol., 77/1, 185–189. doi: 10.2113/gsecongeo.77.1.185 batista-rodríguez, j.a. & pérez-flores, m.a. (2021): contribution of ert on the study of ag-pb-zn, fluorite, and barite deposits in northeast mexico.– minerals, 11, 249, 1–16. doi:10.3390/min11030249 bishop, j. r. & emerson, d. w. (1999): geophysical properties of zinc‐bearing deposits.– aust. j. earth sci., 46/3, 311–328. doi: 10.1046/j.1440-0952.1999.0 borojević šoštarić, s., palinkaš, a.l., strmić palinkaš, s., bermanec, v., neubauer, f., spangenberg, j.e. & prochaska, w. (2009): origin of siderite–barite-polysulfide mineralisation in petrova and trgovska gora mts., nw dinarides.– miner petrol, 97, 111–128. borojević šoštarić, s., roglić, m., milošević, a., brenko, t. (2022): žune ba-f epithermal deposit part 1: mineralogical and geochemical characteristics.– geol. croat., 75/3, 393–410. doi: 10.4154/gc.2022.24 cardarelli, e. & de donno, g. (2019): advances in electric resistivity tomography: theory and case studies.– in: persico, r., piro, s. & linford, n. (eds.): innovation in near-surface geophysics, 23–57, elsevier. doi:10.1016/b9780-12-812429-1.00002-7 čičić, s. (1976): mineralne sirovine bosne i hercegovine: ii knjiga – ležišta nemetala.– geoinženjering, sarajevo, 231–446. de groot-hedlin, c. & constable, s. (1990): occam’s inversion to generate smooth, two-dimensional models form magnetotelluric data.– geophysics, 55, 1613–1624. doi: 10.1190/1.1442813 dey, a. & morrison, h.f. (1979): resistivity modelling for arbitrary shaped twodimensional structures.– geophys. prospect., 27, 1020–1036. doi: 10.1111/j.1365 2478.1979.tb00961.x edwards, l.s. (1977): a modified pseudosection for resistivity and induced polarization.– geophysics, 42, 1020–1036. evrard, m., dumont, g., hermans, t., chouteau, m., francis, o., pirard, e. & nguyen, f. (2018): geophysical investigation of the pb–zn deposit of lontzen–poppelsberg, belgium.– minerals, 8/6, 233. doi:10.3390/ min8060233 ford, k., keating, p. & thomas, m.d. (2007): overview of geophysical signatures associated with canadian ore deposits.– in: goodfellow, w.d. (ed.): mineral deposits of canada: a synthesis of major deposit types, district metalg eo lo gi a c ro at ic a geologia croatica 76/156 logeny, the evolution of geological provinces, and exploration methods. geological association of canada, mineral deposits division, st. john’s, 939–970. garašić, v. & jurković, i. (2012): geochemical characteristics of different iron ore types from the southern tomašica deposit, ljubija, nw bosnia. – geol. croat. 65/2, 255–270. doi:10.4154/gc.2012.16 grubić, a. & cvijić, r. (2003): new contribution in geology and metallogeny of the ljubija iron mine. institute of mining prijedor, prijedor, 137 p. grubić, a., cvijić, r., milošević, a. & čelebić, m. (2015): importance of olistostrome member for metallogeny of ljubija iron ore deposits.– arch. techn. sci., 13/1, 1–8. doi: 10.7251/afts.2015.0713.001g grubić, a. & protić, lj. (2003): novi prilozi za geologiju i metalogeniju rudnika gvožđa ljubija.– rudarski institute, prijedor, 63–137. hrvatović, h. (2006): geological guidebook through bosnia and herzegovina.– geological survey of federation bosnia and herzegovina, sarajevo, 163 p. jeremić, m. (1958): baritno-fluoritno ležište žune kod ljubije.– rudarko-metalurški zbornik, 4, 465–474. jurić, m. (1971): geologija područja sanskog paleozoika u sjeverozapadnoj bosni.– poseb. izd. geol. glas., 11, 1–146. loke, m.h., acworth, i. & dahlin, t. (2003): a comparison of smooth and blocky inversion methods in 2d electrical imaging surveys.– explor. geophys., 34/3, 182–187. doi: 10.1071/eg03182 loke, m.h. & barker, r.d. (1996): rapid least-squares inversion of apparent resistivity pseudosections by a quasi-newton method.– geophys. prospect., 44, 131–152. doi: 10.1111/j.1365-2478.1996.tb00142.x meju, m.a. (2002): geoelectromagnetic exploration for natural resources: models, case studies and challenges.– surveys in geophysics, 23, 133–205. doi: 10.1023/a:1015052419222 milošević, a., alekseev, a., zaytseva, e., novak, m., kolar jurkovšek, t. & jurkovšek, b. (2021): late carboniferous biota from the ljubija iron mine area, bosnia and herzegovina.– geologija, 64/(1), 65– 80, doi: 10.5474/geologija.2021.004 palinkaš, a.l., borojević šoštarić, s., strmić palinkaš, s., prochaska, w., pécskay, z., neubauer, f. & spangenberg, j.e. (2016): the ljubija geothermal field: a herald of the pangea break-up (nw bosnia and herzegovina).– geol. croat., 69/1, 3–30. doi: 10.4154/gc.2016.02 pamić, j. (1993): eoalpine to neoalpine magmatic and metamorphic processes in the northwestern vardar zone, the easternmost periadriatic zone and the southwestern pannonian basin.– tectonophysics, 226/1–4, 503–518. doi: 10.1016/00401951(93)90135-7 pamić, j., gušić, i. & jelaska, v. (1998): geodynamic evolution of the central dinarides.– tectonophysics, 297/1–4, 251–268. doi: 10.1016/s00401951(98)00171-1 schmid, s.m., berza, t., diaconescu, v., froitzheim, n. & fügenschuh, b. (1998): orogen-parallel extension in the southern carpathians.– tectonophysics, 297/(1), 209–228. doi: 10.1016/s0040-1951(98)00169-3 schön, j.h. (2011): physical properties of rocks a workbook.– in: cubitt, j. (ed.): vol. 8: handbook of petroleum exploration and production. elsevier, netherlands, 273–335. strmić palinkaš, s., spangenberg, j.e. & palinkaš a.l. (2009): organic and inorganic geochemistry of ljubija siderite deposits, nw bosnia and herzegovina.– miner deposita, 44, 893–913. doi 10.1007/s00126-009-0249-z telford, w.m., geldart, l.p., sheriff, r.e. (1990): applied geophysics, 2nd edt.– cambridge university press. tomljenović, b. (2002): strukturne značajke medvednice i samoborskog gorja [structural characteristics of the mt. medvednica and the samoborsko gorje mt. – in croatian].– phd thesis, faculty of mining, geology and petroleum engineering, university of zagreb, 208 p. ward, s.h. (1990): resistivity and induced polarization methods.– geotechnical and environmental geophysics, volume i: review and tutorial, 147–190. doi: 10.1190/1.9781560802785.ch6 willingshofer, e. (2000): extension in collisional orogenic belts: the late cretaceous evolution of the alps and carpathians.– phd thesis, vrije university, amsterdam, 146 p. 2022 | 75/1 | 129–144 | 14 figs. | 5 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the pre-neogene basement of the croatian portion of the pannonian basin represents a part of the alpine-carpathian-dinaridic orogenic system, predominantly covered by younger deposits (schmid et al., 2020). it is mainly composed of igneous and metamorphic rocks (e.g. pamić, 1986, 1999). only a minor part of these units is exposed at the surface as isolated outcrops, e.g. the palaeozoic granito-metamorphic complex/complexes of the psunj and papuk mts. (e.g. pamić & lanphere, 1991; balen et al., 2006, 2015; horvat et al., 2018) with the late devonian granitoids (380±4 to 283±5 ma, horvat et al., 2018), or the late cretaceous granite of the moslavačka gora (82 ± 1 ma, starijaš et al., 2010) and the late cretaceous bimodal basalt and rhyolite complex along with accompanying a-type granites (83.6±1.5 ma, balen et al. 2020) of the požeška gora (šparica & pamić, 1986; pamić et al., 1988, 1988/1989; balen et al., 2020). although hydrocarbon exploration has provided valuable borehole material from the pre-neogene basement units of the croatian part of the pannonian basin, the published data remain scarce, which causes uncertainty when reconstructing the major tectonic units. since the eastern part of the slavonia-srijem depression (ssd) in eastern croatia represents the area where the adria-derived tectonic units, the europe-derived tectonic units and the sava zone are juxtaposed (schmid et al., 2020), we chose this area to study the granites and spatially associated acidic rocks from samples obtained from boreholes. this paper petrography and geochemistry of granitoids and related rocks from the pre-neogene basement of the slavonia-srijem depression (croatia) sanja šuica1, vesnica garašić2 and alan b. woodland3 1 ina-industrija nafte, d.d., upstream laboratory, lovinčićeva 4, 10000, zagreb, croatia; (sanja.suica@ina.hr) 2 university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, 10000, zagreb, croatia 3 goethe universität frankfurt, institut für geowissenschaften, altenhöferallee 1, 60438 frankfurt, germany doi: 10.4154/gc.2022.09 abstract the pre-neogene basement of the slavonia-srijem depression (eastern croatia) is composed of various types of igneous, metamorphic and sedimentary rocks. here we present the petrography and geochemistry of a heterogenous group represented by two types of alkali granite, granite, syenite, rhyolite and orthogneiss. the alkali granite type 1 has an a-type geochemical affinity: a ferroan character, high alkali content, high concentration of rare earth elements (ree3+), rb, zr, nb and y, and low cao, mgo, p2o5, ba, sr and eu contents. the syenite has similar characteristics, but displays enrichment in ba, k, eu and zr, which could be a consequence of feldspar and zircon accumulation. the alkali granite type 2 is an a-type granite but differs from the alkali granite type 1 in having lower k2o and rb, accompanied by higher na2o and sr concentrations, possibly resulting from alteration or a different parental magma/evolutionary process. the granite and rhyolite are distinguished from both types of alkali granite by their magnesian character, lower zr, nb and y concentrations, less pronounced eu negative anomaly, as well as higher ba, sr and lree/hree. the orthogneiss displays differences in major element chemistry compared to the alkali granite type 1, but has similar trace element and ree patterns. the alkali granites are characterized by y/nb<1.2, indicating an ocean island basalt-like source, while the granite originated from melting of a crustal, probably metasedimentary source. the atype granites could belong to the late cretaceous a-type magmatism of the sava zone, while the granite is significantly different from the sava zone a-type granites as well as the other rocks investigated in this study. reports the results of petrography and whole-rock geochemistry for two types of alkali granite, granite, syenite, rhyolite and orthogneiss as well as the mineral chemistry for alkali granite type 1. the aim of this study was to define granitoid rocks in the preneogene basement of the ssd, obtain information about their sources, potential genetic relationships and suggest the regional context of the examined rocks. 2. geological setting the sava zone is defined as a relatively narrow belt composed of various types of igneous and metamorphic rocks along with the late cretaceous sedimentary rocks. it is interpreted as a suture zone between the european plate (tisia-dacia) and the adriatic plate, stretching e-w from zagreb to belgrade and nnw-sse along the vardar river to the aegean sea (fig. 1; schmid et al., 2008, 2020; ustaszewski et al., 2010). according to schmid et al. (2008), the north-western tip of the sava zone takes on a sw-ne strike, following the mid-hungarian fault zone. ustaszewski et al. (2009, 2010) interpreted the sava zone as an ocean basin, a relic of the mesozoic tethys (vardar ocean) that remained open during the late cretaceous and early palaeogene. according to gallhofer et al. (2015) the subduction of this oceanic lithosphere led to establishment of the late cretaceous magmatic arc of the apuseni-banat-timok-srednogorie belt. one of the most distinctive features of the sava zone is the late cretaceous bimodal magmatism, manifested predominantly by basic and acidic volcanism with minor shallow plutonism (e.g. article history: manuscript received may 20, 2021 revised manuscript accepted november 22, 2021 available online january 31, 2022 keywords: a-type granite, pre-neogene basement, slavonia-srijem depression, sava zone g eo lo gi a c ro at ic a geologia croatica 75/1130 pamić, 2002), outcropping on the požeška gora in croatia (šparica & pamić, 1986; pamić et al., 1988, 1988/1989), the kozara (ustaszewski et al., 2009; cvetković et al., 2014) and the prosara (pamić & injuk, 1988; ustaszewski et al., 2010) in bosnia and herzegovina and the klepa in north macedonia (prelević et al., 2017). this bimodal magmatism covers the time span of 83.6-81 ma (ustaszewski et al., 2009; balen et al., 2020). the geodynamic context of this magmatism varies between different authors: it is possibly related to a backarc basin (pamić, 2002; ustaszewski et al., 2009), or an anomalous iceland-type mid-oceanic ridge (cvetković et al., 2014), or a continental rift/pseudo-rift (belak et al., 1998), or an upper-plate fore-arc basin (prelević et al., 2017), or due to intracontinental extension induced by transtensional tectonics (prelević et al., 2017). the acidic magmatism itself also has various interpretations: from a product of partial melting of basic oceanic crust on the kozara (cvetković et al., 2014), or a product of basic melt fractionation, along with minor crustal contamination on the požeška gora (pamić et al., 2000). the atype granite of the požeška gora is considered to be a product of partial melting of the continental crust, along with a possible mantle contribution (balen et al., 2020). besides this bimodal volcanism, late cretaceous ultrapotassic lamprophyric volcanism was recently described at the ripanj locality, near belgrade, serbia by sokol et al. (2020). they attributed this volcanism to melts derived from the partial melting of metasomatized lithospheric mantle either in a fore-arc or an intracontinental setting associated with transtensional tectonics. the eastern part of the ssd is completely covered by quaternary deposits (brkić et al., 1989; čičulić-trifunović & galović, 1984). according to the regional interpretations of schmid et al. (2008, 2020), the pre-neogene basement of the ssd includes adria-derived tectonic units, the sava zone and europe-derived units (fig. 2). it is mainly composed of igneous (diabase, gabbro, granite, syenite) and metamorphic (gneiss and mica schist, low grade metasediments) rocks, while sedimentary rocks such as flysch-like sandstones and shales are subordinate. based on the results of whole rock k-ar ages, pamić & pécskay (1994) considered basic rocks from the ssd to comprise part of a late cretaceous ophiolite sequence. the granite and gneiss, along with low grade metamorphic rocks have been correlated with the hercynian complex of the papuk mts. (pamić & lanphere 1991). 3. sampling and analytical methods a brief overview on the core samples along with the borehole number, depth interval and type of analysis is provided in table 1. the borehole data was obtained from ina-industrija nafte d.d. well reports. in the studied boreholes, the basement is composed of alkali granite type 1 (b-1 borehole, apparent thickness > 205 m), alkali granite type 2 (b-2 borehole, apparent thickness > 98 m), syenite (b-3 borehole, apparent thickness > 61 m), ortho gneiss (b-4 and b-5 boreholes, apparent thickness > 57 m and 308 m, respectively) and cataclastic porphyritic granitic breccia with rhyolite fragment (b-6 borehole, apparent thickness of 489 m). a rhyolite fragment was sampled along with the granite in order to test whether there is any cogenetic relationship between these two types of rocks. the orthogneiss from b-4 and b-5 boreholes was sampled for the same reason, i.e. to check for a possible relationship with the adjacent granites. the sampled rocks are covered by late miocene marls, except in b-5, where early-middle miocene breccia-conglomerates are present. the only borehole that was drilled through the studied units was b-6, where flysch-like interbedded sandstone and shale underlie the granitic breccia. in total, nine samples were investigated from six boreholes. petrographic analysis was done using leitz wetzlar orthoplan and figure 1. regional map of the major tectonic units simplified after schmid et al. (2020). europe-derived units include the tisia and dacia megaunits, while the adria-derived units include the adriatic microplate, deformed adriatic margin and adria-derived thrust sheets. oceanic units are the neotethyan obducted ophiolites. the yellow rectangle denotes the position of the study area depicted in fig. 2. mg: moslavačka gora, pp: papuk, ps: psunj, pg: požeška gora, pr: prosara, ko: kozara. g eologia c roatica šuica et al.: petrography and geochemistry of granitoids and related rocks from the pre-neogene basement of the slavonia-srijem depression (croatia) 131 olympus bx51 polarizing microscopes at the upstream laboratory, ina-industija nafte, d.d., zagreb. modal analysis was obtained by point-counting of at least 500 points. the mineral chemistry for one sample was obtained with a jeol jxa 8900 electron probe micro-analyser (epma) at the institut für geowissenschaften, goethe universität frankfurt. measurements on a carbon-coated thin section and polished grain mount were performed in wavelength-dispersive mode (wds) with a 15 kv accelerating voltage, a 20 na (12 na for feldspars) beam current and ~ 3 μm beam diameter. raw data were corrected with the citzaf quantitative matrix correction implemented by jeol. the whole rock chemical analysis was performed by inductively coupled plasma emission spectroscopy (icp-es) for major elements, carbon and sulphur, while trace elements including rare-earth elements (ree) were determined by inductively coupled plasma mass spectrometry (icp-ms), at the bureau veritas minerals, vancouver, canada. the rocks were analysed after sample solution by 4-acid digestion of 0.25 g sample, while the ree were determined after libo2/li2b4o7 fusion and nitric acid digestion of a 0.1 g sample. detection limits for icp-es analyses was 0.01%, except for sio2 (0.04%), al2o3 (0.03%) and fe2o3 (0.04%), while detection limits for icp-ms analysis were 0.1 ppm. gcdkit 4.1 (janoušek et al., 2006) was used for data handling. 4. results the granitoid rocks analysed in this study are classified based on geochemical characteristics, using the classification of de la roche et al. (1980; fig. 3). the main reason for using this classification instead of the quartz-alkali feldspar-plagioclase (qap) table 1. list of samples with borehole number, depth interval and type of analysis. wra – whole rock analysis. empa – mineral chemistry by electron probe micro-analyser. sample borehole depth interval (m) analysis rock type b-1-3 b-1 1010-1011 wra alkali granite type 1 b-1-4 b-1 1070-1072 wra alkali granite type 1 b-1-5 b-1 1140-1141.5 wra, empa alkali granite type 1 b-2-1 b-2 1028-1029.5 wra alkali granite type 2 b-3-5 b-3 1093-1099 wra syenite b-4-5 b-4 1156-1158.5 wra orthogneiss b-5-2 b-5 1568-1570 wra orthogneiss b-6-2 b-6 1427-1430 wra granite b-6-2 b-6 1427-1430 wra rhyolite figure 2. map of the major tectonic units of the study area with an approximate outline of the slavonia-srijem (ss) depression, along with the position of the boreholes from which the samples were obtained. simplified after schmid et al. (2020). figure 3. classification diagram based on major elements after de la roche et al. (1980). g eo lo gi a c ro at ic a geologia croatica 75/1132 classification of streckeisen (1974) based on modal composition is the lack of mineral chemistry data for all the samples. consequently, we have not made the distinction between albite with <5% ab component, which is according to strec keisen (1974), included in the alkali feldspar group and albite with >5% ab which is included in the plagioclase group. rhyolite is classified according to major element composition, i.e. total alkali-silica diagram (le bas et al, 1986; not displayed). 4.1. petrography the alkali granite type 1 (samples b-1-3, b-1-4, b-1-5) is a pinkcoloured, leucocratic, medium-grained rock with an equigranular texture (fig. 4a) and is locally porphyritic. the rock is composed of k-feldspar (58-67%) and quartz (25-37%) followed by minor albite (2-6%), accessory biotite and hornblende, magnetite, ilmenite, zircon and apatite. the subsolidus mineral assemblage includes chlorite (1-2%), stilpnomelane, allanite, epidote, fluorite, titanite, haematite, pyrite, calcite, sericite and kaolinite. anhedral k-feldspar (up to 5 mm) has perthitic texture with irregular albite lamellae (20-50% of the host mineral). it forms graphic intergrowths with quartz, which is especially pronounced in the finegrained matrix of the porphyritic varieties, where these intergrowths are irregular and of different size. quartz (up to 3 mm) is anhedral, with undulose extinction. prismatic albite (up to 2 figure 4. photomicrographs of: a) k-feldspar (kfs) and quartz (qtz) in equigranular alkali granite type 1 (b-1-5); b) clusters of albite (ab), biotite (bt) and hornblende (hbl) with chlorite (chl) and epidote (ep) replacing albite in alkali granite type 1 (b-1-5); c) albite (ab), sericitized k-feldspar (kfs) and quartz (qtz) in alkali granite type 2 (b-2-1); d) k-feldspar (kfs), albite (ab) and quartz (qtz) in syenite (b-3-5), interstitial biotite (bt); e) granite (b-6-2) with quartz (qtz) and k-feldspar (kfs) containing albite (ab) inclusions; f ) rounded quartz (qtz) phenocrysts, k-feldspar (kfs) with albite (ab) inclusions, sericite (ser) in groundmass of rhyolite (b-6-2r); g) kfeldspar (kfs) microcline (mc), quartz (qtz) and biotite (bt) in gneiss (b-5-2); h) k-feldspar (kfs) porphyroclast mantled by quartz (qtz) and secondary chlorite (chl) in gneiss (b-4-5). abbreviations of mineral names after whitney & evans (2010). g eologia c roatica šuica et al.: petrography and geochemistry of granitoids and related rocks from the pre-neogene basement of the slavonia-srijem depression (croatia) 133 mm), with thin polysynthetic twining, is associated with rounded clusters of hornblende and biotite (fig. 4b), where it is characterized by altered cores containing different proportions of small epidote grains and/or chlorite aggregates, usually surrounded by fresh albite rims. biotite (up to 2 mm) is the most abundant mafic mineral and it occurs as anhedral flakes, with light to dark brown pleochroism. it is mainly interstitial to feldspar and quartz. hornblende (< 1 mm) is euhedral to subhedral, pleochroic from light to dark green and is mainly altered to stilpnomelane and minor chlorite, along with epidote, titanite and opaques. the alkali granite type 2 (b-2-1) is a grey to pinkish, leucocratic, fine-grained (<1.5 mm) rock, characterized by pronounced quartz-feldspar graphic intergrowths. it generally has an equigranular texture (fig. 4c) but is locally porphyritic. the rock is composed of quartz (46%), albite (40%) and k-feldspar (8%), followed by accessory apatite, zircon and opaques. subsolidus minerals include sericite (6%), chlorite, haematite, carbonate and kaolinite. feldspars and quartz (to a lesser extent) occur as larger grains, and in the granophyric groundmass of the porphyritic variety. they are extensively altered to sericite. albite locally has an antiperthitic texture, with k-feldspar exsolution lamellae, and a subordinately altered core with fresh rim. k-feldspar is perthitic. the primary ferromagnesian mineral has been completely altered to chlorite. chlorite and sericite also occur interstitially as fan-shaped aggregates. the syenite (b-3-5) is a pinkish, leucocratic, coarse-grained rock, displaying a cataclastic and locally granular texture. the rock is composed of k-feldspar (56%) and albite (32%), followed by minor quartz (5%), biotite (4%), and hornblende (2%). accessory minerals are zircon, apatite and opaques. subsolidus minerals are chlorite, epidote, haematite, carbonate, sericite and kaolinite. microstructures indicative of the plastic deformation were observed: e.g. larger grains of k-feldspar surrounded by myrmekite, distortion of polysynthetic twining in albite and kink-bands in biotite laths. k-feldspar (up to 30 mm) has an anhedral habit, perthitic texture, and contains inclusions of albite. albite (up to 10 mm) is anhedral and displays thin polysynthetic twinning. it occurs predominantly with narrow fresh rims around altered grains. quartz is anhedral, interstitial, and up to 0.5 mm in size (fig. 4d). biotite (up to 2 mm) is interstitial, with light to dark brown pleochroism. hornblende (up to 2 mm) is subhedral and pleochroic from light to dark green. the granite (b-6-2) is leucocratic rock, with red k-feldspar, pinkish-orange albite and greyish quartz, displaying seriate porphyritic texture (fig. 4e). k-feldspar megacrysts occur locally. the texture is locally cataclastic, with fragments of granite in a dark green matrix, and shear zones up to 1 cm wide. the rock is composed of albite (37%), k-feldspar (31%) and quartz (26%). accessory minerals are zircon, apatite and opaques. subsolidus minerals are chlorite (6%), white mica, clay minerals and carbonate. k-feldspar (0.1 to >50 mm) has an anhedral habit and perthitic texture with thin albite exsolution. larger grains of k-feldspars contain inclusions of albite microliths and quartz grains. k-feldspar megacrysts are anhedral, without sharp boundaries with surrounding matrix and contain zonally distributed quartz, albite and chlorite inclusions (up to 0.5 mm in size). these large grains also exhibit cracks filled with subsolidus quartz or carbonate. albite (0.1 to 15 mm) has an anhedral to subhedral habit and thin polysynthetic twining. larger albite grains contain k-feldspar and quartz inclusions. quartz (up to 10 mm) is anhedral, displaying segmentation, undulose extinction and deformation lamellae. larger quartz grains contain albite, k-feldspar and chlorite inclusions. chlorite (0.1-1.5 mm) displays light green to green pleochroism. it occurs as pseudomorphs after primary ferromagnesian minerals, probably biotite, with opaque inclusions and locally developed kink-band structures. it also occurs as interstitial and fracture filling fine-grained aggregates. the rhyolite (b-6-2r) is a light olive grey rock with aphyric texture and a phenocryst to matrix ratio of 1:40. it contains few phenocrysts of quartz and subordinate feldspar in a devitrified spherulitic and micropoikilitic groundmass (fig. 4f). quartz phenocrysts (~0.5 mm) are rounded, sub rounded, subhedral and partially embayed. quartz is also a part of the groundmass, filling cuspate areas between spherulites. feldspar phenocrysts (up to 1.1 mm) are subhedral, with a prismatic habit and are almost completely altered to sericite and clay minerals. the groundmass is composed of quartz, feldspar and secondary white mica. the orthogneiss (b-5-2, b-4-5), with porphyroclastic texture, contains pinkish feldspar porphyroclasts in greyish green matrix. the foliated fabric is defined by the alternation of quartz and/or quartz-feldspar ribbons and strips of parallel-oriented mica. the rock is composed of quartz (35-45%), albite (20-28%), k-feldspar (13-25%), muscovite (5-12%), biotite (6%), garnet (1%) and local clinozoisite (0-3%). accessory minerals are zircon, apatite and opaque minerals, along with local tourmaline. secondary minerals are chlorite, sericite, carbonate, haematite, pyrite and clay minerals. quartz (0.05 to 2 mm) is anhedral, displaying subgrains or undulose extinction, mainly forming monomineralic aggregates. larger quartz grains, locally mantled by fine-grained quartz aggregates, display segmentation to prismatic subgrains. k-feldspar (0.1 to 20 mm) is anhedral, locally with tartan twinning (fig. 4 g). it is mainly associated with quartz-rich domains. larger k-feldspar grains are perthitic, locally surrounded by finegrained aggregates of quartz and subordinately plagioclase, contain fractures and display undulose extinction (fig. 4h). albite (0.1 to 2 mm) has an anhedral habit and thin polysynthetic twining, which is locally deformed. biotite (0.1 to 1 mm) has an anhedral habit and light to dark brown pleochroism. it occurs in quartz domains and as inclusions inside larger k-feldspar grains and locally forms lenticular clusters. muscovite (0.1 to 0.6 mm) is anhedral to subhedral and parallel-oriented, forming the strips. garnet (0.1-1 mm) is anhedral to subhedral and mainly atollshaped. clinozoisite (up to 1 mm), occuring only in sample b-45, displays a preferred orientation of elongate grains. 4.2. mineral chemistry the sample of the alkali granite type 1 (b-1-5) was selected for mineral chemical analysis based on petrographic observations. the rest of the samples have not been subjected to the analysis of mineral chemistry due to alteration. the analysed minerals were amphibole, biotite and feldspar. the results of the selected epma analyses of amphibole from the alkali granite type 1 (b-1-5) are listed in table 2. the structural formula of amphibole was calculated based on 23 oxygen atoms and 15 cations. according to leake et al. (1997), the analysed amphibole is calcic with cab>1.5 atom per formula unit (apfu), corresponding to ferro-edenite (fig. 5), with (na+k)a = 0.54-0.75 apfu. the fe/(fe+mg) ratios range from 0.79 to 0.85, while total aluminium altot is low (1.08-1.34 apfu). the results of the selected epma analyses of biotite are provided in table 3. the structural formula of biotite was calculated based on 24 atoms (o, oh) and 15 cations. the analysed biotite corresponds to annite, with fe/(fe+mg) ratio ranging from 0.66 g eo lo gi a c ro at ic a geologia croatica 75/1134 to 0.71, and tio2 contents ranging from 1.57 to 3.77 wt%. in a mg vs. altot diagram (fig. 6), most biotite analyses display chemical characteristics of biotite from alkaline-peralkaline rocks (nachit et al., 1985). the results of the selected epma analyses of feldspars from the alkali granite type 1 (b-1-5) are listed in table 4. the structural formula was calculated based on 8 oxygen atoms. both k-feldspar and albite exsolution lamellae were analysed, along with single albite grains associated with clusters of mafic minerals. k-feldspar is homogeneous with a composition or94-98ab2-6. albite exsolution lamellae range in composition from an0 to an5, similar to albite grains, which range in composition from an4 to an6 and are homogeneous. the k-feldspar component in the plagioclase ranges from or1 to or2. figure 5. classification diagram for the amphiboles from the alkali feldspar granite (b-1-5 sample) after leake et al. (1997). table 2. selected epma analyses and structural formulae of amphibole from the alkali granite type 1 (b-1-5). calculated based on 23 oxygen atoms and 15 cations. sample b-1-5 b-1-5 b-1-5 b-1-5 b-1-5 b-1-5 b-1-5 b-1-5 b-1-5 b-1-5 b-1-5 b-1-5 mineral amphibole amphibole amphibole amphibole amphibole amphibole amphibole amphibole amphibole amphibole amphibole amphibole grain 1 1 2 2 2 3 3 3 3 3 3 3 position core core rim rim core rim rim core rim rim rim rim sio2 42.23 43.36 42.70 42.58 42.87 42.25 42.83 42.66 42.81 43.14 43.26 43.16 tio2 1.54 1.37 1.64 1.60 1.71 1.19 1.11 1.19 1.14 1.19 1.21 1.54 al2o3 6.65 5.71 7.07 7.11 6.82 7.05 6.75 6.90 6.84 6.91 7.19 6.54 cr2o3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.02 0.00 0.02 0.01 0.00 feo 29.67 30.06 28.70 28.86 27.74 29.58 29.15 29.37 29.66 29.25 29.32 29.06 mno 0.72 0.61 0.64 0.67 0.63 0.72 0.72 0.72 0.74 0.72 0.66 0.73 nio 0.00 0.01 0.02 0.01 0.00 0.00 0.01 0.00 0.01 0.02 0.00 0.04 mgo 3.16 2.98 3.59 3.56 4.21 3.25 3.50 3.52 3.24 3.25 3.17 3.28 cao 10.08 8.42 10.07 10.01 9.95 10.04 10.11 10.08 9.96 9.99 10.17 9.96 na2o 2.46 3.23 2.53 2.51 2.44 2.29 2.20 2.42 2.39 2.35 1.97 2.43 k2o 0.95 0.77 1.03 0.99 0.97 1.07 1.07 1.07 1.11 1.06 0.98 0.91 s 97.93 96.86 98.00 97.91 97.34 97.45 97.44 97.95 97.91 97.91 97.93 97.65 si 6.76 6.98 6.76 6.75 6.79 6.76 6.83 6.78 6.81 6.84 6.84 6.85 al(iv) 1.23 1.02 1.24 1.25 1.21 1.24 1.17 1.22 1.19 1.16 1.16 1.15 st 7.99 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 al(vi) 0.01 0.06 0.07 0.08 0.06 0.08 0.10 0.07 0.09 0.13 0.18 0.08 ti 0.19 0.17 0.20 0.19 0.20 0.14 0.13 0.14 0.14 0.14 0.14 0.18 fe2 3.57 3.64 3.42 3.44 3.31 3.56 3.50 3.51 3.55 3.49 3.49 3.47 fe3 0.40 0.40 0.38 0.38 0.37 0.40 0.39 0.39 0.39 0.39 0.39 0.39 mn 0.10 0.08 0.09 0.09 0.08 0.10 0.10 0.10 0.10 0.10 0.09 0.10 mg 0.75 0.72 0.85 0.84 0.99 0.77 0.83 0.83 0.77 0.77 0.75 0.78 sc 5.02 5.07 5.00 5.03 5.02 5.05 5.05 5.04 5.04 5.01 5.03 5.00 ca 1.73 1.45 1.71 1.70 1.69 1.72 1.73 1.72 1.70 1.70 1.72 1.69 na 0.25 0.48 0.29 0.27 0.29 0.23 0.22 0.24 0.26 0.29 0.25 0.31 sb 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 na 0.51 0.53 0.49 0.50 0.46 0.48 0.46 0.51 0.48 0.43 0.35 0.44 k 0.19 0.16 0.21 0.20 0.20 0.22 0.22 0.22 0.23 0.21 0.20 0.18 sa 0.71 0.69 0.69 0.70 0.66 0.70 0.68 0.72 0.70 0.65 0.55 0.62 g eologia c roatica šuica et al.: petrography and geochemistry of granitoids and related rocks from the pre-neogene basement of the slavonia-srijem depression (croatia) 135 4.3. whole-rock geochemistry nine samples were analysed for major and trace elements, including ree: three samples of alkali granite type 1 (b-1-3, b-1-4, b-1-5), one sample of alkali granite type 2 (b-2-1), syenite (b-35), granite (b-6-2), rhyolite (b-6-2r) and two samples of orthogneiss (b-5-2, b-4-5). the whole-rock analyses are presented in table 5. the analysed rocks have a wide range of sio2 content (61.1577.89 wt%). harker diagrams exhibit negative correlations between sio2 and al2o3, feot, cao, p2o5, and tio2 contents (fig. 7). the k2o and na2o contents are positively correlated with sio2, with an exception of the highest alkali content in the syeni te (b-3-5) and the lowest k2o content in the alkali granite type 2 (b-2-1). the mgo content is generally low (0.12-1.28 wt%), displaying a slight negative correlation with sio2. all analysed rocks have low p2o5 contents (0.01-0.19 wt%). in the classification scheme of frost et al. (2001) and frost & frost (2008), based on three variables: fe*, modified alkali-lime index (mali) and aluminium saturation index (asi), the analysed samples display certain differences. regarding the fe*, index defined as feotot/(feotot+mgo) (fig. 8a), both types of alkali granite and syenite, along with one sample of the orthogneiss (b-5-2) are classified as ferroan (fe*=0.81-0.93), while the granite, rhyolite, and the other orthogneiss sample ( b-4-5) are classified as magnesian (fe*=0.65-0.78). based on the mali index defined as na2o+k2o-cao (fig. 8b), the figure 6. discrimination diagram for biotite from the alkali feldspar granite (b1-5 sample) after nachit (1985). sid; siderophyllite, phlog: phlogopite, east: eastonite, ann: annite, zw: zinnwaldite. table 3. selected epma analyses and structural formulae of biotite from the alkali granite type 1 (b-1-5). calculated based on 24 atoms (o, oh) and 15 cations. sample b-1-5 b-1-5 b-1-5 b-1-5 b-1-5 b-1-5 mineral biotite biotite biotite biotite biotite biotite grain 1 1 2 2 3 3 position core rim core rim core rim sio2 29.47 34.46 36.55 36.39 36.1 36.32 tio2 1.13 2.02 3.66 3.77 3.55 3.25 al2o3 13.93 12.42 12.61 12.91 12.33 13.12 cr2o3 0.01 0 0 0.03 0 0 feo 36.75 31.6 29.26 29.23 29.6 28.6 mno 0.31 0.31 0.27 0.27 0.7 0.22 nio 0.01 0.03 0 0 0 0.03 mgo 6.48 5.41 4.47 4.07 4.8 4.71 cao 0.09 0.04 0.01 0.04 0 0.01 na2o 0 0.03 0.04 0.04 0.03 0.07 k2o 1.91 7.25 8.86 9.18 9.12 9.07 s 90.29 93.94 95.75 95.93 96.21 95.82 si 4.86 5.47 5.63 5.6 5.58 5.61 al (iv) 2.71 2.32 2.29 2.34 2.25 2.39 st 7.57 7.79 7.92 7.95 7.83 7.99 al (vi) 0 0 0 0 0 0 ti 0.14 0.24 0.42 0.44 0.41 0.38 fe3+ 2.03 1.68 1.51 1.51 1.53 1.48 fe2+ 3.04 2.52 2.26 2.26 2.3 2.22 mn 0.04 0.04 0.03 0.03 0.04 0.03 mg 1.59 1.28 1.03 0.93 1.11 1.08 sm 6.84 5.75 5.25 5.17 5.38 5.18 ca 0.02 0.01 0 0.01 0 0 na 0 0.01 0.01 0.01 0.01 0.02 k 0.4 1.47 1.74 1.8 1.8 1.79 si 0.42 1.48 1.75 1.82 1.81 1.81 table 4. selected epma analyses and structural formulae of feldspar from the alkali granite type 1 (b-1-5). calculated based on 8 oxygen atoms. sample b-1-5 b-1-5 b-1-5 b-1-5 b-1-5 b-1-5 mineral k-feldspar k-feldspar albite albite albite albite grain 1 1 1 2 2 3 position core rim lamella core rim rim sio2 64.24 64.70 68.06 67.35 67.60 67.70 al2o3 17.97 17.93 19.54 19.81 19.65 19.68 fe2o3 0.02 0.06 0.10 0.64 0.33 0.06 bao 0.04 0.02 0.00 0.02 0.04 0.01 cao 0.00 0.05 0.61 0.76 1.04 0.95 na2o 0.34 0.40 11.39 10.96 11.00 11.20 k2o 16.58 15.91 0.18 0.13 0.08 0.21 s 99.23 99.11 99.94 99.67 99.75 99.87 si 3.00 3.01 2.98 2.96 2.97 2.97 al 0.99 0.98 1.01 1.03 1.02 1.02 fe3+ 0.00 0.00 0.00 0.02 0.01 0.00 ba 0.00 0.00 0.00 0.00 0.00 0.00 ca 0.00 0.00 0.03 0.04 0.05 0.04 na 0.03 0.04 0.97 0.93 0.94 0.95 k 0.99 0.95 0.01 0.01 0.00 0.01 s 5.01 4.98 5.00 4.99 4.99 5.00 or 96.99 96.04 0.98 0.75 0.44 1.15 ab 3.01 3.70 96.18 95.61 94.64 94.44 an 0.00 0.26 2.85 3.64 4.93 4.41 g eo lo gi a c ro at ic a geologia croatica 75/1136 table 5. results of whole-rock chemical analyses. ag 1 alkali granite type 1; ag 2 alkali granite type 2; loi loss on ignition; a/nk=al2o3/(na2o+k2o); fe*= feotot/( feotot+mgo); mali=na2o+k2o-cao; asi=al/(ca-1.67×p+na+k). major element in wt%; trace element in ppm. sample b-1-5 b-1-3 b-1-4 b-1-5 b-2-1 b-5-2 b-4-5 b-6-2 b-6-2r rock type syenite ag 1 ag 1 ag 1 ag 2 orthogneiss orthogneiss granite rhyolite sio2 61.15 72.59 74.57 74.66 77.89 67.11 68.21 69.52 75.18 tio2 0.88 0.27 0.19 0.2 0.12 0.62 0.54 0.41 0.08 al2o3 17.31 13.71 12.85 12.84 12.91 15.18 15.03 14.54 14.08 fe2o3 4.53 2.37 1.94 1.99 1.11 3.63 3.76 2.58 0.7 mno 0.07 0.04 0.03 0.02 <0.01 0.09 0.06 0.06 <0.01 mgo 0.97 0.22 0.13 0.14 0.12 0.83 1.28 1.28 0.18 cao 2.07 0.84 0.64 0.55 0.07 2.32 1.51 1.05 0.26 na2o 4.6 4.5 4.04 3.92 5.25 3.24 3.05 3.7 3.09 k2o 6.05 4.58 4.77 4.94 1.41 3.84 4.12 4.62 5.07 p2o5 0.19 0.05 0.03 0.03 0.01 0.2 0.18 0.16 0.03 loi 2 0.7 0.7 0.6 1 2.8 2.1 1.9 1.2 s 99.79 99.88 99.89 99.9 99.93 99.85 99.85 99.85 99.96 ba 597 251 192 217 78 429 472 595 698 rb 105.7 198.5 216.8 206.4 66.4 129.6 162.8 207.9 194.1 sr 191.2 48.4 39 36.5 100.6 139 85.4 171.2 87.4 y 22.1 42.5 44.2 49.1 39.3 45.4 38.5 17.7 15.6 nb 35 43.6 49.2 43.7 46.4 16.8 17.2 16 11.1 zr 630.9 283.5 320.5 324.2 205.1 236.5 246.6 175.1 56.3 hf 13.8 8.7 9.9 10 8 5.9 6.8 4.5 2.4 ta 1.9 4.1 4.4 3.6 4.4 2.1 1.6 1.4 1.2 th 4.5 22.9 25.9 22.8 31 30.7 16.2 14.6 14.5 u 2.1 4.1 5.5 5 4.9 4.8 8.6 8.2 4.3 sc 8 4 2 2 <1 11 10 5 3 co 8 1.3 1.3 1.7 0.7 5.6 6.2 4.2 0.6 cs 0.9 4.4 4.2 4.8 0.9 11.1 6 4.6 3.7 pb 2 5.4 7.8 6.5 4 5 11.5 10.2 10.6 zn 30 54 50 40 11 57 33 43 6 ni 3.4 1 0.7 0.8 0.7 3.2 4.5 4.8 1.5 ga 23.8 23.2 22.8 22.5 23.6 19.5 22.6 19.2 14.9 la 24.3 55.1 48.6 47.2 45.6 45.7 43.4 38.4 15.5 ce 47.3 105.8 91 89.6 86 90.7 91.9 70.1 28.3 pr 5.5 11.17 9.72 9.7 8.39 10.81 10.42 7.33 3.26 nd 21.9 37.8 35.1 35.6 29.3 40.6 39.1 24.8 11.8 sm 4.16 7.29 7.27 7.64 6.2 9.2 8.13 4.18 2.5 eu 1.33 0.63 0.52 0.53 0.24 1.37 0.96 0.91 0.52 gd 3.97 7.05 7.44 7.75 5.99 8.85 7.61 3.51 2.76 tb 0.66 1.22 1.21 1.4 1.11 1.37 1.21 0.56 0.42 dy 3.84 7.39 7.59 8.68 6.54 7.65 6.79 2.66 2.59 ho 0.9 1.51 1.54 1.74 1.42 1.64 1.44 0.59 0.49 er 2.46 4.31 4.64 5.43 4.4 4.41 4.01 1.48 1.5 tm 0.38 0.73 0.69 0.81 0.7 0.62 0.59 0.24 0.23 yb 2.5 5.03 4.78 5.33 4.51 4.47 4.01 1.77 1.46 lu 0.36 0.72 0.7 0.76 0.7 0.63 0.57 0.29 0.23 sree 119.56 245.75 220.8 222.17 201.1 228.02 220.14 156.82 71.56 a/nk 1.23 1.11 1.09 1.09 1.27 1.60 1.59 1.31 1.33 fe* 0.81 0.91 0.93 0.93 0.89 0.80 0.73 0.65 0.78 mali 8.58 8.24 8.17 8.31 6.59 4.76 5.66 7.27 7.9 asi 0.98 0.99 0.99 1.01 1.26 1.13 1.25 1.14 1.28 eu/eu* 1.00 0.27 0.22 0.21 0.46 0.37 0.72 0.60 0.61 (la/sm)cn 3.65 4.72 4.17 3.86 4.59 3.10 3.33 5.74 3.87 (gd/yb)cn 1.28 1.13 1.26 1.18 1.07 1.60 1.54 1.60 1.53 g eologia c roatica šuica et al.: petrography and geochemistry of granitoids and related rocks from the pre-neogene basement of the slavonia-srijem depression (croatia) 137 samples mainly plot in the alkali-calcic field, except for the syenite and alkali granite type 2, which plot in the alkalic and calcic fields, respectively. regarding the asi index defined as al/(ca-1.67p+na+k), the alkali granite type 1 and the syenite are metaluminous, to slightly peraluminous while the rest of the samples are peraluminous (fig. 8c). harker diagrams for selected trace elements are displayed in fig. 9. among the lile (light ion lithophile elements), the ba and sr contents are negatively correlated with sio2. exceptions are the granite and the rhyolite in the ba vs. sio2 diagram and sr vs. sio2 diagram, as well as the alkali granite type 2 in the sr vs. sio2 diagram. rb contents are positively correlated with sio2, except for the alkali granite type 2, which is characterized by very low concentrations. among the hfse (high field-strength elements), zr, nb and y concentrations display considerable scatter, with very high zr in the syenite, very low zr in the rhyolite, high nb in both types of alkali granite and the syenite and high y in both types of alkali granite and the orthogneiss. primitive mantle normalized (sun & mcdonough, 1989) trace element patterns (fig. 10) indicate a general enrichment of incompatible over compatible elements. both types of alkali granite and the orthogneiss display negative ba, sr, p, eu, and ti anomalies, as well as a negative nb anomaly. the syenite displays distinctive positive anomalies in k and zr, as well as slightly negative anomalies in sr, p, and ti. the granite and the rhyolite display negative ba, nb, sr, p, and ti anomalies and have a distinctive positive pb anomaly. chondrite normalized (mcdonough & sun, 1995) ree patterns are generally similar for all samples (fig. 11), with slight lree enrichment (la/sm)cn=3.10-5.74 and an almost flat hree pattern (gd/yb)cn=1.07-1.60. the main difference between the samples is a negative eu anomaly, which is well pronounced in both types of alkali granite (eu/eu*=0.12-0.27), moderately pronounced in the orthogneiss (eu/eu*=0.37-0.46), less pronounced in the granite and rhyolite (eu/eu*=0.60-0.72) and absent in the syenite (eu/eu*=1.00). 5. discussion the results of petrographic analysis indicate that the rocks presented in this study comprise a very heterogenous group. both types of the alkali granites and the rhyolite have preserved the igneous fabric, the syenite and granite were affected by brittle figure 7. harker variation diagrams of major element oxides for the analysed whole rocks. magmatic series fields in e) after pecerillo & taylor (1976). pg: požeška gora. granite (balen et al., 2020); ko: kozara acidic rocks (ustaszewski et al., 2009); ps prosara granite (pamić & injuk, 1988). g eo lo gi a c ro at ic a geologia croatica 75/1138 and subordinately plastic deformation, but with the preserved igneous microstructure on a thin-section scale, while the orthogneiss was subjected to plastic deformation. the alkali granite type 1 and syenite are characterized by their similar mineralogical composition, with the main difference of lower quartz, accompanied by higher plagioclase, biotite and hornblende modal content in the syenite compared to the alkali granite type 1. syenite is like the alkali granite type 1 with anhedral biotite and subhedral hornblende as ferromagnesian phases, while it differs from the alkali granite by the presence of two feldspars, defining its clear subsolvus character. the alkali granite type 1 is mainly composed of hypersolvus alkali feldspar, indicating high-temperature and low-pressure crystallization at higher crustal levels. the granophyric intergrowths imply a high degree of magma undercooling and are very common in shallow intrusions (vernon, 2004; lowenstern et al., 1997; candela, 1997; deer et al., 2013). single albite grains, present in minor proportions (<6%), are restricted to clusters of mafic minerals, possibly representing an early phase of crystallization. albite is characterized by fresh rims and cores altered to chlorite and epidote, which could be a consequence of the crystallization of these clusters at a deeper level, thus prior to final emplacement. the subhedral habit of hornblende indicates that it crystallized earlier than the interstitial biotite, which represents a late crystallizing phase. primary hornblende indicates a minimum water content of 4 wt. % in the melt (dall’agnol et al. 1999). the high fe contents of hornblende and biotite indicate crystallization under reducing conditions. the alkali granite type 2 is characterized by high quartz and plagioclase content as well as minor k-feldspar and accessory amounts of mafic minerals. like the alkali granite type 1, it is also characterized by granophyric intergrowths, but with a finer grain size. the granite is composed of plagioclase, k-feldspar and quartz, with minor chlorite replacing a primary ferromagnesian mineral, probably biotite. the rock has porphyritic texture charafigure 8. classification diagrams based on the major elements after frost et al. (2001): a) sio2 – feotot/(feotot+mgo); b) sio2 – na2o+k2o-cao; c) asi – a/nk. symbols as in fig. 7. figure 9. harker variation diagrams of trace elements for the analysed whole rocks. symbols as in fig. 7. g eologia c roatica šuica et al.: petrography and geochemistry of granitoids and related rocks from the pre-neogene basement of the slavonia-srijem depression (croatia) 139 figure 10. primitive mantle-normalized multi-element patterns for: a) alkali granite type 1; b) orthogneiss; c) alkali granite type 2 and syenite; d) granite and rhyolite. normalization values for the primitive mantle after sun & mcdonough (1989). pg: požeška gora alkali feldspar granite (data from balen et al., 2020), ko: kozara acidic rocks (ustaszewski et al., 2009). figure 11. ree chondrite-normalized patterns for: a) alkali granite type 1; b) orthogneiss; c) alkali granite type 2 and syenite; d) granite and rhyolite. normalization values for chondrite after mcdonough & sun (1995). pg: požeška gora granite (data from balen et al., 2020), ko: kozara acidic rocks (ustaszewski et al., 2009). g eo lo gi a c ro at ic a geologia croatica 75/1140 cterized by the same minerals occurring as the phenocrysts and as a part of the groundmass, which is the evidence of two-stage cooling, caused by abrupt increase in undercooling (vernon, 2004; candela, 1997). this could be a consequence of magma ascent to shallower levels or rapid loss of water, both processes pointing to crystallization in higher crustal levels. the existence of two feldspars indicates subsolvus crystallization, probably due to high water pressure (deer et al., 2013). the rhyolite is characterized by aphyric texture with sparse quartz and feldspar phenocrysts in the spherulitic and micropoikilitic groundmass. according to bachman & bergantz (2004), the crystal-poor rhyolites are the products of interstitial melt extraction from the silicic crystal mush preserved as granitoid after the crystallization. the orthogneiss is characterized by higher quartz and mica contents, compared to the analysed granitoids, as well as a predominance of plagioclase over k-feldspar. quartz ribbons with elongated subgrains and undulose extinction, as well as porphyroclasts of k-feldspar with intracrystalline cracks and undulose extinction indicate plastic deformation under the low-grade metamorphic conditions. 5.1. geothermobarometry the al content in amphibole can be used for estimation of the pressure (depth) of emplacement in hornblende-bearing granite (hammastrom & zen, 1986; hollister et al., 1987; johnson & rutherford, 1989; schmidt, 1992; mutch et al., 2016). based on the microstructural characteristics of the alkali granite type 1 indicating shallow emplacement, we applied the geobarometer of johnson & rutherford (1989), since it was specifically developed for low pressure conditions. our pressure estimation for the alkali granite type 1 ranges between 1.2 and 2.5 kbar, with the higher-pressure value corresponding to a depth of ~8 km. according to anderson & smith (1995), the al-in-hornblende geobarometer is suitable only for amphiboles with fe/(fe+mg)<0.65 and granitic systems with t<800°c, otherwise the pressure will be overestimated. the fe/(fe+mg) ratio of the analysed amphibole from the alkali feldspar granite (b-1-5) is 0.79 and 0.85, so the pressures calculated with al-inhornblende barometer should be considered as an upper pressure limit. the magmatic temperatures of the analysed igneous rocks were estimated by a zircon saturation thermometer (watson & harrison, 1983). this temperature refers to an estimate of melt temperature before extensive crystallization (miller et al., 2003). the thermometer is based on a zircon solution solubility model defined as ln dzr=12900/t-0.85×(m-1)-3.80, where dzr is distribution coefficient of zr between zircon and melt, t is the absolute temperature (k) and m is the cationic ratio defined as m=(na+k+2ca)/(al×si). all samples are within the calibration range for the value of cationic ratio m (1.09-1.49), except for the syenite (m=1.79). estimated temperatures are relatively high for the alkali granite type 1 (831-850°c) and type 2 (832°c), lower for granite (797°c) and lowest for the rhyolite (721°c). a revised zircon saturation thermometer (boehnke et al., 2013) defined by ln dzr=(10108±32)/t-(1.16±0.15)(m-1)-(1.48±0.09) yielded lower temperatures, namely 789-813°c for alkali granite type 1, 805°c for alkali granite type 2, 754°c for granite and 673°c for rhyolite. the obtained temperatures are generally in line with microstructural observations. 5.2. granite typology the geochemical discrimination scheme of frost et al. (2001) clearly discriminates two groups of analysed rocks, ferroan, consisting of both types of alkali granite, syenite and one sample of orthogneiss and magnesian, consisting of granite, rhyolite and the other sample of orthogneiss. according to frost & frost (2011), the category of ferroan granites is equal to the a-type granite. alkali granite type 1 is indeed an a-type granite as defined by loiselle & wones, (1979); collins et al. (1982), whalen et al. (1987) and eby (1990) which is evident from its mineral chemistry (fe-rich rich biotite and fe-rich hornblende as ferromagnesian phases), major element contents (high feot/ (mgo+feot), k2o, na2o, accompanied by low cao, mgo, and p2o5) i.e. ferroan, alkali-calcic and metaluminous to slightly peraluminous character, as well as trace element concentrations (high ree3+, rb, zr, nb and y, and low ba, sr and eu). it is characterized by a ree pattern typical for a-type granites, with a pronounced negative eu anomaly, significant lree enrichment and an almost flat hree (papoutsa et al., 2015). the alkali granite type 2 also has an a-type affinity, as implied by its major element chemistry (high feot/(mgo+feot), na2o, low cao and mgo), trace element concentrations (high ree3+, nb and y, low ba and eu) as well as the shape of the ree pattern. the exception from the classical a-type granite definition is low k2o and rb, as well as a high sr concentration. consequently, it is a ferroan, calcic (due to low k2o) and peraluminous rock. the syenite, with its ferroan, alkali and metaluminous character is geochemically similar to the alkali granite type 1 in terms of major and trace element contents and could also be defined as an a-type rock. the main differences are positive k and zr anomalies in a primitive mantle normalized trace element plot and a smooth chondrite normalized ree pattern with no eu anomaly in the syenite. the high ga/al of both types of alkali granite and the syenite confirms the a-type affinity of these rocks (whalen et al., 1987, fig. 12). additionally, the a-type affinity of both types of alkali granite is corroborated by within-plate character based on rb, nb, ta, y and yb concentrations, while the syenite, due to lower ta is not exclusively placed in the within-plate field (pearce et al., 1984, fig. 13). on the other hand, the granite differs from the above described a-type rocks by its magnesian character, lower zr, nb and y concentrations, less pronounced eu negative anomaly, higher ba, sr and lree/hree. the granite probably correfigure 12. discrimination diagram for granites after whalen et al. (1987). i & s: iand s-type granites, a: a-type granites. symbols as in fig. 7 pg: požeška gora granite (data from balen et al., 2020). g eologia c roatica šuica et al.: petrography and geochemistry of granitoids and related rocks from the pre-neogene basement of the slavonia-srijem depression (croatia) 141 sponds to an s-type rock since it is peraluminous, characterized by low cao at given feot, as well as relatively high pb, rb and k2o (chapell & white, 1974, 2001). on the other hand, resolving the typology of this rock is not straightforward because it is also characterized by relatively high na2o and sio2<72 wt.%. the rhyolite is magnesian, alkali-calcic and peraluminous like granite, with similar trace element and ree patterns. the orthogneiss generally has primitive mantle normalized trace element patterns and chondrite normalized ree patterns, very similar to the alkali granite type 1. y concentration is high and similar to both types of alkali granite. it plots on the border of an a-type and i/s type fields in the zr vs. 10000*ga/al diagram (fig. 12), and mainly displays within-plate character based on rb, nb, ta, y and yb concentration (fig. 13). on the other hand, it is characterized by moderate feot/(mgo+feot), higher cao and p2o5, as well as lower nb, unlike the alkali granite types 1 and 2. according to bonin (2008), the y content and ree patterns are reliable indicators of a-type affinity of orthogneiss, while major element contents and nb concentrations are more prone to change during the metamorphic processes. thus, it is possible that a protolith of porphyritic granite is similar to the analysed alkali granite type 1. 5.3. petrogenesis the similarity between alkali granite type 1 and syenite has already been mentioned in the previous section. the positive k and zr anomalies, an eu/eu* ~1 of the syenite and enrichment in ba compared to alkali granite type 1, point to k-feldspar, plagioclase and zircon crystal accumulation and a silicic cumulate origin for this rock (schaen et al., 2017). significant negative ba, sr and eu anomalies in the alkali granite type 1, along with the fact that these anomalies are absent (ba and eu) or considerably less pronounced (sr) in the syenite, indicate that these rocks could be related through the processes of fractional crystallisation/crystal accumulation. the process of feldspar accumulation also explains the elevated mali index and resulting offset to the alkali series for the syenite (frost & frost, 2008). the less pronounced ti negative anomaly followed by the absence of nb depletion in syenite and higher nb/ta in syenite (18.42) compared to alkali granite type 1 (10.63-12.13) points to biotite accumulation (were & keppler, 2021). the alkali granite type 2, with its ree pattern similar to alkali granite type 1 and more pronounced eu depletion could represent the more fractionated member of the same series, but lower k2o and rb, accompanied by higher na2o and sr cannot be explained by a fractionation process. while alteration of the alkali granite type 2 could be a possible cause of such differences, a different parental magma or alternative evolutionary process(es) cannot be excluded. frost & frost (2011) claim that ferroan calcic peraluminous granites are theoretically possible, but they have not identified any examples of this peculiar composition. since the ree of the alkali granite type 1 and the syenite, display almost parallel chondrite normalized patterns, apart from the eu/eu*, it is reasonable to conclude that this pattern was not affected by the late-stage process of fractional crystallization/ crystal accumulation and can be used as a proxy for the source rock or parental magma composition. the enrichment in lree, coupled with the flat hree pattern and negative sr anomaly, common to both syenite and alkali feldspar granite type 1 indicate the presence of clinopyroxene/hornblende and plagioclase, along with the absence of garnet in the residual or early-stage fractionating assemblage (hanson, 1979). the negative p and ti anomalies could be a result of apatite and ti-bearing mineral in the residual or early-stage fractionating assemblage (e.g. rollinson & pease, 2021). figure 13. discrimination diagrams for granites after pearce et al. (1984). wpg: within plate granite, syn-colg: syncollisional granite; vag: volcanic arc granite; org: ocean ridge granite. symbols as in fig. 7 g eo lo gi a c ro at ic a geologia croatica 75/1142 the origin of a-type granites, particularly the nature of their magma source, is a matter of long-lasting debate (summarized in bonin, 2007). proposed models for a-type magma generation include: a) direct fractionation of mantle-derived magma that could be accompanied by the interaction with crustal rocks (eby, 1990; chen et al. 2009); b) partial melting of crustal material – for instance, previously melted lower crustal granulitic residues (collins et al., 1982; whalen et al., 1987), or tonalitic to granodioritic rocks that suffered no previous episode of partial melting (creaser et al., 1991). according to frost & frost (2011), ferroan granites, their substitute for a-type granite term, could be generated by extreme differentiation of basalts, by partial melting of tonalitic to granodioritic crustal rocks, or by a combination of these processes. eby (1992) distinguished two types of a-type granite: a1-type granite, derived from an ocean-island basalt (oib)-like source and possibly related to intracontinental rifting events and an a2-type granite, derived from a crustal source and related to post-collisional extension. since the author explicitly claims that his discrimination can be applied only on rocks that plot in the a-type granite field of whalen et al. (1987) and the within-plate granite field of pearce et al. (1984), we plotted exclusively the alkali granite type 1 and 2 in the discrimination diagrams y-nb-ce and y-nb-3ga (fig. 14). based on these diagrams, both alkali granite types 1 and 2 plot in the a1-type field. this should be taken with caution due to a restricted dataset and the fact that they plot close to the boundary with the a2-field. on the other hand, the granite probably represents an s-type granite, originating from the melting of immature, feldspar-rich metasedimentary crustal rock. rhyolite could originate from the melting of similar parental material, but the dataset is insufficient to establish any reliable connection between these rocks. weak eu negative anomalies in the granite and the rhyolite, accompanied by negative sr and ba anomalies point to residual or fractionated plagioclase and k-feldspar, while hree depletion in the porphyritic granite suggests residual/fractionated garnet. negative anomalies of nb and ti point to a residual/fractionated ti-phase, while a negative p anomaly indicates residual/fractionated apatite. 5.4. possible surface counterparts pamić & lanphere (1991) considered the granites and gneiss from the studied boreholes as the hercynian s-type granites and migmatites of the papuk mts. however, according to pamić et al. (1996) the s-type granites of papuk have a lower alkali content (k2o+na2o), lower k2o/na2o ratio, higher cao, along with different trace element concentrations (higher ba and sr, lower rb, etc.), so granites and gneiss from this study cannot be correlated with the papuk s-type granites. the only known a-type granites in the wider region of eastern croatia, northern bosnia and herzegovina or north-western serbia are the a-type granites associated with late cretaceous bimodal magmatism of the sava zone on the požeška gora (pamić, 1987; balen et al., 2020) and the prosara. (pamić & injuk, 1988; ustaszewski et al., 2010). the a-type granite of the požeška gora is a hypersolvus granite, as is the alkali granite type 1 from this study and displays many similarities with both types of alkali granite and syenite from this study, including trace element and ree patterns, high feot/(mgo+feot), k2o and na2o, accompanied by low cao and mgo (fig.7). on the other hand, the a-type granite of the požeška gora is an a2-type according to eby (1992) and it is characterized by lower nb ( fig. 9). the prosara a-type granite, which was subjected to lowgrade solid-state deformation (ustaszewski et al., 2010), also displays similar major element and trace element geochemistry (pamić & injuk, 1988; fig. 7, fig. 9). however, the nb concentration for the prosara a-type granite is even lower than the požeška gora a-type granite (fig. 13). if the studied a-type granites are indeed late cretaceous and if they represent a protolith for the studied orthogneiss, then the low-grade metamorphic event that produced this gneiss could be the same as that proposed for the prosara a-type granite, that is a palaeogene compressional phase (ustaszewski e al., 2010). rhyolites are an important part of the late cretaceous bimodal complexes of the požeška gora (pamić et al., 2000) and the kozara (ustaszewski et al., 2009). the rhyolite from this study compared to the požeška gora rhyolite and the kozara rhyolite has a different ree signature (fig.11) with higher eu/eu*, (gd/yb)cn and (la/sm)cn,. the granite is significantly different from the a-type granites of the sava zone as well as the a-type rocks analysed in this study. however, it is impossible to set a reliable correlation based on geochemical and petrographic data, so any connection with surface outcrops remains open and unconstrained. further work focused on radiometric and isotope data is necessary for resolving a number of open questions presented in this paper. radiometric age data would, besides putting the analysed rocks in a figure 14. discrimination diagrams for a-type granites after eby (1992). g eologia c roatica šuica et al.: petrography and geochemistry of granitoids and related rocks from the pre-neogene basement of the slavonia-srijem depression (croatia) 143 regional geological context, aid in testing the hypothesis of the presumed co-genetic relationship of the alkali granite type 1 and the syenite, or speculation about the alkali granite type 1-like protolith for the analysed orthogneiss. additionally, isotope data are necessary for resolving the origin of the parental magmas, especially for the analysed alkali granites, which were according to the classification of eby (1992) derived from an enriched mantle source. since the a-type granites are indicators of large-scale extensional events (e.g. bonin, 2007), the rocks presented in this study could be crucial for understanding the tectonic evolution of the study area and consequently the wider area of the europe-adria suture zone. 6. conclusions this paper presented analysis of the petrography and geochemistry of the granitoids and related rocks from the pre-neogene basement of the ssd. these data enabled the recognition of two types of alkali granite, granite and syenite. the spatially related orthogneiss and rhyolite were also included in this study. although the dataset is relatively restricted, several conclusions can be drawn. the alkali granite type 1 is a hypersolvus granite, crystallized from a high-temperature shallow intrusion (with <8 km depth of intrusion). the overall characteristics of this rock point to an a-type affinity, while the trace element ratios (y/nb) indicate the mantle source of the parental magma (i.e. a1-type affini ty). the syenite displays geochemical and mineralogical features like the alkali granite type 1, but with the characteristics of a silicic cumulate rock. the alkali granite type 2 is an a-type granite too, with a1-type affinity, but compared to the alkali granite type 1, is characterized by low k2o and rb, accompanied by high na2o, which could be a consequence of alteration or different parental magma/evolutionary process(es). these rocks could tentatively be related to the a-type granites of the sava zone. the granite is porphyritic, indicating a shallow-intrusion origin, but with a subsolvus two-feldspar assemblage, pointing to crystallization under higher water pressure compared to the alkali granites presented. overall geochemical characteristics, namely the magnesian character, clearly suggest that it is not genetically related to the a-type rocks described above. geochemical characteristics suggest the s-type affiliation of this rock. the associated rhyolite displays certain similarities with the granite but setting any connection between these rocks is impossible based on the presented dataset. acknowledgement the authors are grateful to mario matošević and lutz nasdala for their critical comments that helped to improve an early version of the manuscript. neven šuica is acknowledged for graphical help. we are very greatful to three anonymus reviewers for valuable reviews. this work was supported by the croatian ministry of science, education and sports ( 195-1951293-0237). references anderson, j.l. & smith, d.r. (1995): the effects of temperature and fo2 on the alin-hornblende barometer.– am. mineral., 80, 549–559. bachman, o. & bergantz, g.w. (2004): on the origin of crystal-poor rhyolites: extracted from batholitic crystal mushes.– j petrology, 45/8, 1565–1582. doi: 10.1093/petrology/egh019 balen, d., schneider, p., massonne, h.-j., opitz, j., luptáková, j., putiš, m. & petrinec, z. (2020): the late cretaceous a-type alkali-feldspar granite from mt. požeška gora (n croatia): potential marker of fast magma ascent in the europe –adria suture zone.– geol. carpathica, 71, 361–381. doi: 10.31577/geolcarp.71.4.5 balen, d., massonne, h.-j. & petrinec, z. (2015): collision-related early paleozoic evolution of a crustal fragment from the northern gondwana margin (slavonian mountains, tisia mega-unit, croatia): reconstruction of the p–t path, timing and paleotectonic implications.– lithos, 232, 211–228. doi: 10.1016/j.lithos.2015.07.003 balen, d., horvath, p., tomljenović, b., finger, f., humer, b., pamić, j. & arkai, p. (2006): a record of pre-variscan barrovian regional metamorphism in the eastern part of the slavonian mountains (ne croatia).– mineral. petrol., 87, 143–162. doi: 10.1007/s00710-006-0120-1 belak, m., halamić, j., marchig, v. & tibljaš, d. (1998): upper cretaceouspalaeogene tholeiitic basalts of the southern margin of the pannonian basin: požeška gora mt (croatia).– geol. croat., 51, 163–174. boehnke p., watson e.b., trail d., harrison t.m. & schmitt a.k. (2013): zircon saturation re-revisited.– chemical geology, 351, 324–334. doi: 10.1016/j. chemgeo.2013.05.028 bonin, b. (2008): death of super-continents and birth of oceans heralded by discrete atype granite igneous events: the case of the variscan–alpine europe.– j. geosci., 53, 237–252. doi: 10.3190/jgeosci.036 bonin (2007): a-type granites and related rocks: evolution of a concept, problems and prospects.– lithos, 97, 1–29. doi: 10.1016/j.lithos.2006.12.007 brkić, m., galović, i. & buzaljko, r. (1989): osnovna geološka karta sfrj 1:100 000 list vinkovci [basic geological map of sfry 1:100 000, sheet vinkovci – in croatian].– savezni geološki zavod, beograd. candela, p.a. (1997): a review of shallow, ore-related granites: textures, volatiles, and ore metals.– j petrology, 38/12, 1619–1633. doi: 10.1093/petroj/38.12.1619 chappell b.w. & white a.j.r. (2001): two contrasting granite types: 25 years later.– austral ian journal of earth sciences, 48, 489–499. doi: 10.1046/j.1440-0952.2001.00882.x chappell, b.w. & white, a.j.r. (1974): two contrasting granite types.– pacific geology 8, 173–174. chen, l., ma, c.q., she, z.b., mason, r., zhang, j.y. & zhang, c. (2009): petrogenesis and tectonic implications of a-type granites in the dabie orogenic belt, china: geochronological and geochemical constraints.– geol mag, 146, 638–651. doi: 10.1017/s0016756808005918 collins, w.j., beams, s.d., white, a.j.r. & chappell, b.w. (1982): nature and origin of a-type granites with particular reference to southeastern australia.– contrib. to mineral. petrol., 80, 189–-200. doi: 10.1007/bf00374895 creaser, r.a., price, r.c. & wormald, r.j. (1991): a-type granites revisited: assessment of a residual-source model.– geology, 19, 63–166. doi: 10.1130/0091-7613(1991)019%3c0163:atgrao%3e2.3.co;2 cvetković, v., šarić, k., grubić, a., cvijić, r. & milošević, a. (2014): the upper cretaceous ophiolite of north kozara – remnants of an anomalous mid-ocean ridge segment of the neotethys?– geol. carpathica, 65, 117–130. doi: 10.2478/geoca-2014-0008 čičulić-trifunović, m. & galović, i. (1984): osnovna geološka karta sfrj 1:100 000: list bačka palanka [basic geological map of sfry 1:100 000, sheet bačka palanka].– savezni geološki zavod, beograd. dall’agnol, r., scaillet, b. & pichavant, m. (1999): an experimental study of a lower proterozoic a-type granite from the eastern amazonian craton, brazil.– j. petrol. 40, 11, 1673–1698. doi: 10.1093/petroj/40.11.1673 deer, w.a., howie, r.a. & zussman, j. (2013): an introduction to the rock-forming minerals.mineralogical society, london, 498 p. doi: 10.1180/dhz de la roche, h., leterrier, j., grandclaude, p. & marchal, m. (1980): a classification of volcanic and plutonic rocks using r1r2-diagram and major element analyses – its relationships with current nomenclature.– chem. geol. 29, 183– 210. eby, g.n. (1992): chemical subdivision of the a-type granitoids: petrogenetic and tectonic implications.– geology, 20, 641–644. eby, g.n. (1990): the a-type granitoids: a review of their occurrence and chemical characteristics and speculations on their petrogenesis.– lithos, 26, 115–134. doi: 10.1016/0024-4937(90)90043-z frost, b.r. & frost, c.d. (2008): a geochemical classification for feldspathic igneous rocks.– j petrology, 49/11, 1955–1969. doi: 10.1093/petrology/egn054 frost, b.r., barnes, c.g., collins, w.j., arculus, r.j., ellis, d.j. & frost, c.d. (2001): a geochemical classification for granitic rocks.– j. petrol., 42/11, 2033– 2048. doi: 10.1093/petrology/42.11.2033 frost, c.d. & frost, b.r. (2011): on ferroan (a-type) granitoids: their compositional variability and modes of origin.– j. petrol., 52/1, 39–53. doi: 10.1093/petrology/egq070 gallhofer, d., von quadt, a., peytcheva, i., schmid, s.m. & heinrich, c.a. (2015): tectonic, magmatic, and metallogenic evolution of the late cretaceous arc in the carpathian-balkan orogen.– tectonics, 34/9, 1–24. doi: 10.1002/2015tc003834 hammastrom, j.m. & zen, e. (1986): aluminium in hornblende: an empirical igneous geobarometer.– am. mineral., 71, 1297–1313. g eo lo gi a c ro at ic a geologia croatica 75/1144 hanson g.n. (1978): the application of trace elements to the petrogenesis of igneous rocks of granitic composition.– earth planet. sci. lett., 38/1, 26-43. doi: 10.1016/0012-821x(78)90124-3 hollister, s., grissom, g.c., peters, e.k.m., stowell, h.h. & sisson, v.b. (1987): confirmation of the empirical correlation of al in hornblende with pressure of solidification of calc-alkaline plutons.– am. mineral., 72, 231–239. horvat, m., klötzli, u., jamičić, d., buda, g., klötzli, e. & hauzenberger, c. (2018): geochronology of granitoids from psunj and papuk mts., croatia.– geochronometria, 45/1, 198–210. doi: 10.1515/geochr-2015-0099 janoušek, v., farrow, c.m. & erban, v. (2006): interpretation of whole-rock geochemical data in igneous geochemistry: introducing geochemical data toolkit (gcdkit).– j. petrol., 47, 1255–1259. doi: 10.1093/petrology/egl013 johnson, m.c. & rutherford, m.j. (1989): experimental calibration od the aluminium-in-hornblende geobarometer with application to long valley caldera (california).– geology, 17, 837–841. le bas, m.j., le maitre, r.w., streckeisen, a. & zanettin, b. (1986): a chemical classification of volcanic rocks based on the total alkali-silica diagram.– j petrology, 27, 745–750. leake, b.e., woolley, a.r., arps, c.e.s., birch, w.d., gilbert, m.c., grice, j.d., hawthorne, f.c., kato, a., kisch, h.j., krivovichiev, v.g., linthout, k., laird, j., maresch, w.v., nickel, e.h., rock, n.m.s., schumacher, j.c., smith, d.c., stephenson, n.c., ungaretti, l., whittaker, e.j.w. & youzhi, g. (1997): nomenclature of amphiboles: report of the subcommittee on amphiboles of the international mineralogical association, commission on new minerals and mineral names.– can. mineral., 35, 219–246. loiselle, m.c. & wones, d.r. (1979): characteristics and origin of anorogenic granites.– geol. soc. am. abstr. programs, 11, p. 468. lowenstern, j.b., clynne, m.a., & bullen, t.d. (1997): comagmatic a-type granophyre and rhyolite from the alid volcanic center, eritrea, northeast africa.– journal of petrology, 38, 1707–1721. doi: 10.1093/petroj/38.12.1707 mcdonough, w.f. & sun, s.s. (1995): the composition of the earth.– chem. geol., 120, 223–253. doi: 10.1016/0009-2541(94)00140-4 miller, c.f., meschter mcdowell, s. & mapes, r.w. (2003): hot and cold granites? implications of zircon saturation temperatures and preservation of inheritance.– geology, 31, 529–532. doi: 10.1130/0091-7613(2003)031%3c0529:hac gio%3e2.0.co;2 mutch, e.j.f., blundy, j.d., tattitch, b.c., cooper, f.j. & brooker, r.a. (2016): an experimental study of amphibole stability in low pressure granitic magmas and a revised al in hornblende geobarometer.– contrib. mineral. petrol., 171, 85. doi: 10.1007/s00410-016-1298-9 nachit, h., razafimahefa, n., stussi, j.m. & carron, j.p. (1985): composition chimique des biotites et typologie magmatique des granitoides [chemical compositiona of biotite and magmatic typology of granites – in french].– c.r. academic sciences paris, series 2, 301, 813–818. pamić, j. (2002): the sava–vardar zone of the dinarides and hellenides versus the vardar ocean.– eclogae geol. helv., 95, 99–113. pamić, j. (1999): kristalina podloga južnih dijelova panonskog bazena – temeljena na površinskim i bušotinskim podacima [crystalline basement of the south pannonian basin based on surface and subsurface data – in croatian].– nafta, 50, 291–310. pamić, j. (1987): mladoalpinski alkalijsko-feldspatski graniti (aljaskiti) požeške gore u slavoniji [young-alpine alkali feldspar granites (alaskites) from mt. požeška gora in slavonia, northern yugoslavia – in croatian].– geologija, 30, 183–205. pamić, j. (1986): magmatic and metamorphic complexes of the adjoining area of the northernmost dinarides and pannonian mass.– acta. geol. hung., 29, 203–220. pamić, j., belak, m., bullen, t.d., lanphere, m.a. & mckee, e.h. (2000): geochemistry and geodynamics of a late cretaceous bimodal volcanic association from the southern part of the pannonian basin in slavonia (northern croatia).– mineral. petrol., 68, 271–296. pamić, j., lanphere, m. & belak, m. (1996): hercynian i-type and s-type granitoids from the slavonian mountains (southern pannonian basin, northern croatia).– n. jb. miner. abh., 171, 155–186. pamić, j. & pécskay, z. (1994): geochronology of upper cretaceous and tertiary igneous rocks from the slavonia–srijem depression (southern pannonian basin) and their basic petrological features.– nafta, 45, 331–339. pamić, j. & lanphere, m. (1991): hercinske granitne i metamorfne stijene papuka, psunja, krndije i okolne podloge panonskog bazena u slavoniji (sjeverna hrvatska, jugoslavija) [hercynian granites and metamorphic rocks from the mts. papuk, psunj, krndija, and the surrounding basement of the pannonian basin in slavonija (northern croatia, yugoslavia) – in croatian].– geologija, 34, 81–253. pamić, j., injuk, j. & jakšić, m. (1988/1989): prilog geokemijskom poznavanju gornjokredne bimodalne vulkanske asocijacije požeške gore u slavoniji (sjeverna hrvatska, jugoslavija) [some geochemical features of the upper cretaceous bimodal volcanic association from the požeška gore mt. in slavonija (northern croatia, yugoslavia) – in croatian].– geologija, 31, 415–435. pamić, j. & injuk, j. (1988): alpinske granitoidne stijene planine prosare u sjevernoj bosni [alpine granitoid rocks of prosara mt. in northern bosnia, yugoslavia – in croatian].– in: slišković, t. (ed): zbornik referata naučnog skupa „minerali, stijene, izumrli i živi svijet bih“,zemaljski muzej bosne i hercegovine, 93–103. pamić, j., lanphere, m. & mckee, e. (1988): radiometric ages of metamorphic and associated igneous rocks of the slavonian mountains in the southern part of the pannonian basin, yugoslavia.– acta geologica, 18, 13–39. papoutsa, a., pe-piper, g. & piper, d.j.w. (2015): systematic mineralogical diversity in a-type granitic intrusions: control of magmatic source and geological processes.– geol. soc. am. bull. doi:10.1130/b31245 pearce, j.a., harris, n.b.w. & tindle, a.g. (1984): trace element discrimination diagrams for the tectonic interpretation of granitic rocks.– j. petrol., 25/4, 956–983. doi: 10.1093/petrology/25.4.956 pecerillo, a. & taylor, s.r. (1976): geochemistry of eocene calc alkaline volcanic rocks from kastamonu area, northern turkey.– contrib. to mineral. petrol., 58, 63–81. prelević, d., wehrheim, s., reutter, m., romer, r.l., boev, b., božović, m., van den bogaard, p., cvetković, v. & schmid, s.m. (2017): the late cretaceous klepa basalts in macedonia (fyrom) – constraints on the final stage of tethys closure in the balkans.– terra nova, 29, 145–153. doi: 10.1111/ ter.12264 rollinson, h. & pease, v. (2021): using geochemical data: to understand geological properties (2nd ed.).– cambridge: cambridge university press, 358 p. schaen, a.j., cottle, j.m., singer, b.s., keller, c.b., garibaldi, n. & schoene, b. (2017): complementary crystal accumulation and rhyolite melt segregation in a late miocene andean pluton.– geology, 45/9, 835–838. doi: 10.1130/ g39167.1 schmid, s.m., fügenschuh, b., kounov, a., matenco, l., nievergelt, p., oberhänsli, r., pleuger, j., schefer, s., schuster, r., tomljenović, b., ustaszewski, k. & van hinsenberg, d.j.j. (2020): tectonic units of the alpine collision zone between eastern alps and western turkey.– gondwana res., 78, 308–374. doi: 10.1016/j.gr.2019.07.005 schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine-carpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss j. geosci., 101, 139–183. doi: 10.1007/s00015-008-1247-3 schmidt, m.w. (1992): amphibole composition in tonalite as a function of pressure: an experimental calibration of the al-in-hornblende barometer.– contrib. to mineral. petrol., 110/2-3, 266–268. doi: 10.1007/bf00310745 sokol, k., prelević, d., romer, r.l., božović, m., van der bogaard, p., stefanova, e., kostić, b. & čokulov, n. (2020): cretaceous ultrapotassic magmatism from the sava-vardar zone of the balkans.– lithos, 354–355. doi: 10.1016/j.lithos.2019.105268 sun, s.s. & mcdonough, w.e. (1989): chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes.– in: saunders, a.d. & norry, m.j. (eds). magmatism in the ocean basins, saunders, geological society, london, special publications, 42, 313–345. doi: 10.1144/gsl. sp.1989.042.01.19 starijaš, b., gerdes, a., balen, d., tibljaš, d. & finger, f. (2010): the moslavačka gora crystalline massif in croatia: a cretaceous heat dome within remnant ordovician granitoid crust.– swiss. j. geosci., 103/1, 62–82. doi: 10.1007/ s00015-010-0007-3 streckeisen, a. (1974): classification and nomenclature of plutonic rocks. geol. rundsch., 63, 773–786. šparica, m. & pamić, j. (1986): prilog poznavanju tektonike požeške gore u slavoniji. [contribution to the knowledge of tectonics of požeška gora in slavonia – in croatian].– rad jazu, 424, 85–96. ustaszewski, k., kounov, a., schmid, s.m., schaltegger, u., krenn, e., frank, w. & fügenschuh, b. (2010): evolution of the adria-europe plate boundary in the northern dinarides: from continent-continent collision to back-arc extension.– tectonics, 29/6. doi: 10.1029/2010tc002668 ustaszewski, k., schmid, s.m., lugović, b., schaltegger, u., bernoulli, d., hottinger, l., kounov, a., fügenschuh, b. & schefer, s. (2009): late cretaceous intra‐oceanic magmatism in the internal dinarides (northern bosnia and herzegovina): implications for the collision of the adriatic and european plates.– lithos, 108/1-4, 106–125. doi: 10.1016/j.lithos.2008.09.010 vernon, r.h. (2008): a practical guide to rock microstructure.– cambridge university press, cambridge, 606 p. watson, e.b. & harrison, t.m. (1983): zircon saturation revisited: temperature and composition effects in a variety of crustal magma types.– earth planet. sci. lett., 64, 295–304. doi: 10.1016/0012-821x(83)90211-x whalen, j.b., currie, k.l., chappell, b.w. (1987): a-type granites: geochemical characteristics, discrimination and petrogenesis.– contrib. to mineral. petrol., 95, 407–419. doi: 10.1007/bf00402202 were, p. & keppler, h (2021): trace element fractionation between biotite, allanite, and granitic melt.– contrib. mineral. petrol, 176/9, 74. doi: 10.1007/s00410-02101831-3 whitney, d.l. & evans, b.w. (2010): abbreviations for names of rock-forming minerals.– am. mineral., 95/1, 185–187. doi: 10.2138/am.2010.3371 2018 | 71/3 | 121 – 133 | 14 figs. | 3 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the cretaceous to neogene marine successions are in the northern, western and eastern parts of the isparta angle. within the context of the regional stratigraphy, sedimentology and tectonic evolution, many studies were carried out by gutnic et al. (1979), karaman (1990, 1994), yağmurlu (1994), şenel (1997), görmüş & özkul (1995), görmüş et al. (2001, 2004), poisson et al. (2003) and robertson et al. (2003). there are problems concerning the geological mapping, age of sedimentation and environmental interpretation of palaeogene and neogene sediments in the region. in previous studies the marine clastics and the carbonate rock series of the studied area were mainly described as eocene flysch by gutnic et al. (1979), the kayıköy formation (eocene) by yağmurlu (1994), isparta flysch (eocene) by görmüş & özkul (1995), the elmalı formation (lutetian to burdigalian) by şenel (1997) and yavuz flysch (eocene) by poisson et al. (2003). clastic and carbonaceous deposits, belonging to the güneyce formation in the studied area, were interpreted by barrier & vrielynck (2008) as the derinçay formation corresponding to platform or shallow shelf carbonate or terrigenous clastics, deposited at the back-arc basin or on the low-land margin of the active subduction zone placed in the eastern mediterranean basin. the scope of the study is to provide new biostratigraphic data from the sediments of the isparta and the güneyce formations for the new geologic map. the proposed new lower miocene marine clastics of the güneyce formation, which extend in the northern part of the isparta angle, are significant for the eastern mediterranean geology. 2. geological setting there are two different geological interpretations on the stratigraphy of the palaeogene and neogene marine sequences and their revised chrono-biostratigraphy of lower miocene deposits of the eastern mediterranean (sw turkey), based on calcareous nannofossils gülin yavuzlar* and enis kemal sagular suleyman demirel university, faculty of engineering, departament of geological engineering, west campus, cunur, tr32260 isparta, turkey; (corresponding author: gulinyavuzlar@gmail.com*, eniskemal@gmail.com) doi: 10.4154/gc.2018.15 abstract lower miocene deposits of the güneyce formation formerly described as the elmalı formation of lutetian-burdigalian age are located near the villages of gökçebağ (burdur) and yakaören (isparta), (southwestern turkey), eastern mediterranean, and overlie the pre-neogene tectonostratigraphic units of the isparta angle. the purpose of this study is to discuss new biostratigraphic data calibrated to originally classified nannofossil records. three early miocene nannofossil biozones, nn1 triquetrorhabdulus carinatus zone, nn2 discoaster druggii zone and nn3 – sphenolithus belemnos zone, were defined in clastic sediments of the güneyce formation. in addition, one lutetian biozone, np16 – discoaster tanii nodifer zone, was recognized in the remaining outcrops of the isparta formation unconformably underlying the güneyce formation. nannofossil assemblages of shallow marine deposits in the güneyce formation contain high amounts of reworked (palaeogene and cretaceous) specimens. new biostratigraphic data and sedimentary features of the güneyce formation clastics indicate shallow marine deposition and the beginning of the transgression, spreading over an erosional surface on the ophiolitic melange and cretaceous to eocene marine successions rising to the west of the region. structural constructions related to the study area. the accepted former (and common) view is that the eocene marine sedimentary successions (elmalı formation) were overthrust by the ophiolitic melange (gökçebağ melange) after the early miocene (fig. 1). however, the results of this study show that there are two angular unconformable marine successions, the isparta formation (lutetian) and the güneyce formation (early miocene), overlying the ophiolitic melange (fig. 2). in the region, the yavuz flysch (gutnic et al., 1979), was described as marine carbonate and clastics deposited during the paleocene to eocene (lutetian interval) and the second succession, the elmalı formation (şenel, 1997), was described as marine shelf clastics deposited during the lutetian or ranging from the lutetian to the burdigalian. according to görmüş et al. (2001), the studied güneyce formation comprises six lithological units from the bottom to the top: (1) mudstone dominated facies (muddy facies); (2) sandstone dominated facies (sandy facies); (3) olistostrome facies; (4a) rhythmic sandstone-mudstone facies; (4b) carbonate facies; (5) sandstone facies and (6) coarse clastics-conglomerates facies. in this area, there are particularly clastic facies 1 to 4a. the overlying units of the investigated area are plio-quaternary volcanics and quaternary alluvium or colluvial fan deposits. 3. material and methods in this study, 35 samples of various grain-sized clastic or carbonate rocks such as marls, mudstones, sandstones or limestones were collected and examined from 17 locations within the three measured stratigraphic sections. all the study material obtained from yavuzlar (2015) is preserved in the general geology laboratory of suleyman demirel university. the three stratigraphic sections, necibin tepe, arapdere and abidinoğlutaşı tepe were researched in the field (fig. 3). the sedimentary succession article history: manuscript received january 08, 2018 revised manuscript accepted july 16, 2018 available online october 17, 2018 keywords: aquitanian, burdigalian, biostratigraphy, calcareous nannofossils, marine deposits, geologic map g eo lo gi a c ro at ic a geologia croatica 71/3122 of the güneyce formation begins with terrestrial deposits including gypsum and coal-bearing sandy-mudstones, and continues with rhythmic sandstone and mudstone/marl alternations including sand-dominated levels. clastic rock packages seen are partially similar to the depositional facies 1-4a of görmüş et al. (2001). 3.1. stratigraphic sections the necibin tepe stratigraphic section (figs. 3 a, 4) belongs to the first sedimentary levels of the güneyce formation overlying the ophiolitic melange. in the lower part of the succession (up to 44 m), there are sandy mudstones with sandstone interbeds of sandy facies of the güneyce formation, followed by dolomitic limestone lenticular beds within the muddy marine sedimentation. in addition, these levels include lense-shaped gypsum and coal intercalations that could belong to very shallow olistostrome facies. above sixty metres, there is a shallow marine sandstone and mudstone alternation in the upper part of the succession belonging to the rhythmic sandstone-mudstone facies of the güneyce formation. in the necibin tepe section, a transgression figure 1. a new detailed version of the map, built on the existing geologic maps (gutnic et al., 1979, şenel, 1997). figure 2. a new geologic 3d map was built based on nannofossil biostratigraphy (emended from yavuzlar & sagular, 2016). g eologia c roatica yavuzlar and sagular: revised chrono-biostratigraphy of lower miocene deposits of the eastern mediterranean (sw turkey) ... 123 figure 3. measured stratigraphic sections in the güneyce formation: a. necibin tepe stratigraphic cross section, b. arapdere stratigraphic cross section, c. abidinoğlutaşı tepe stratigraphic cross section (emended from yavuzlar & sagular, 2017). figure 4. lithostratigraphy of the necibin tepe section. g eo lo gi a c ro at ic a geologia croatica 71/3124 resulted in deposition of shallow marine sediments on top of terrestrial sedimentary rocks and facies of the succession. the arapdere stratigraphic section (figs. 3 b, 5) belongs to the middle levels of the güneyce formation following the sediments of necibin tepe section. here, sediments and facies of the succession exhibit the rhythmic alternations of mudstones and sandstones representing shallow marine sedimentation. the abidinoğlutaşı tepe stratigraphic section (figs. 3 c, 6) belongs to the rhythmic sandstone-mudstone facies of the güneyce formation, overlies the ophiolitic melange and coincides with the sediments of the arapdere section. the sedimentary successions and facies of this section also include mudstone and sandstone rhythmic alternation representing shallow marine sedimentation. 3.2. investigation methods the standard nannofossil preparation method was used without applying any concentration or cleaning process and taxonomic figure 5. lithostratigraphy of the arapdere section. figure 6. lithostratigraphy of the abidinoğlutaşı tepe section. figure 7. distribution of original nannofossil percentages in the necibin tepe section (* indicates nannofossil data in thin section). g eologia c roatica yavuzlar and sagular: revised chrono-biostratigraphy of lower miocene deposits of the eastern mediterranean (sw turkey) ... 125 concepts were followed perch-nielsen (1985a), bown & young (1998). analyses were carried out by polarized light microscopes at x2500 magnification, using a nikon optiphot-pol and leica dm2700 p, at the department of geology, suleyman demirel university. for each smear slide, nannofossil specimens were counted in 200 fields of view and the identified species were separated into two groups as autochthonous and reworked taxa. in addition, thinned (20-25 microns) petrographic sections were prepared from coarse grained rock samples such as sandstone and limestone (sagular, 2003a, 2003b). nannofossil records within lithoclasts or within the matrix in thin-sections of a sandstone are considered to be mainly reworked sedimentary grains. the nannofossils within intraclasts or within the calcite cement of a calcarenite or limestone could be coeval with sedimentation (synsedimentary). nannofossil records observed in lithoclasts are considered as reworked from extrabasin sources whereas those in intraclasts are considered as removed from elsewhere within the basin. whereas, fossil data found in matrix or cement are considered either reworked or resedimented. thus, the autochthonous or reworked nannofossil assemblages and their sedimentological properties were determined in both nannofossil smear-slides and thin-sections. the results of the laboratory determinations were correlated with field observations and previous studies. melinte (2005), wade & bown (2006) used the nannofossil population as an indicator of sea level changes. sagular (2003b) described another method based on reworked nannofossil data, where the reworked specimen proportions are used as an indicator of sea level changes in coastal environments. the method which sagular (2003b) described is applied in this study. 4. results 4.1. nannofossil biostratigraphy four nannofossil biozones according to martini’s (1971) zonation were identified (fig. 10). 4.1.1. discoaster tani nodifer zone (np16) definition: the last occurrence (lo) of rhabdolithus gladius to the lo of chiasmolithus solitus authors: hay et al. (1967), emend. martini (1970) age: lutetian, middle eocene type locality: the np16 zone covers the isparta formation observed in only a few outcrops within the investigated area (south of gökçebağ village, west of the investigated area, fig. 2). remarks on assemblage: the lo of chiasmolithus solitus in the upper part of the zone and the first occurrence (fo) of reticulofenestra umbilicus and lo blackites inversus at the base figure 8. distribution of original nannofossil percentages in the arapdere section (*indicates nannofossil data in thin section). figure 9. distribution of original nannofossil percentages in the abidinoğlutaşı tepe section (* indicates nannofossil data in thin section). g eo lo gi a c ro at ic a geologia croatica 71/3126 figure 10. biozones and marker nannofossils of the isparta and the güneyce formations. figure 11. smear slide images of dinoflagellate cysts in sample 14g004b:1a-d) t. heimii and coalized thoracosphaera spp. (t. heimii ?); 2-4) t. heimii (pl: polarized light, cl: phase contrast, ql: with quartz wedge, gl: with gypsum wedge). g eologia c roatica yavuzlar and sagular: revised chrono-biostratigraphy of lower miocene deposits of the eastern mediterranean (sw turkey) ... 127 (bown & newsam 2017, perch-nielsen 1985) is noticed in the assemblage with d. saipanensis, d. tanii nodifer, r. dictyoda and s. radians and b. inversus. 4.1.2. triquetrorhabdulus carinatus zone (nn1) definition: lo of helicosphaera recta and/or sphenolithus ciperoensis to the fo of discoaster druggii authors: bramlette & wilcoxon (1967), emend. martini & worsley (1970) age: aquitanian, early miocene type locality: the base of the arapdere section remarks on assemblages: the lo of cyclicargolithus abisectus is observed in the assemblage with t. caritanus, c. floridanus, reticulofenestra bisecta, sphenolithus dissimilis. in this zone, the presence of s. moriformis, s. compactus and t. heimii were observed in samples from the necibin tepe section. in the arapdere section the following species were identified: c. miopelagicus, c. pelagicus, c. abisectus, c. floridanus, r. bisecta, r. gelida, r. producta, s. compactus, s. dissimilis, s. moriformis and t. carinatus. 4.1.3. discoaster druggii zone (nn2) definition: fo of discoaster druggii to the lo of triquetrorhabdulus carinatus. authors: martini & worsley (1970) age: aquitanian to burdigalian, early miocene table 1. list of calcareous nannofossil species distribution, counts and percentages in the necibin tepe section (* indicates thin section nannofossil data). sp ec ie s s. c om pa ct us s. m or ifo rm is t. h ei m ii ∑ c oe va l l ow er m io ce ne % a ut oc ht on ou s r. h es sl an di i s. m or ifo rm is t. sa xe a ∑ e oc en e % re w or ke d eo ce ne m . m ur us w . b ar ne si ae ∑ c re ta ce ou s % re w or ke d c re ta ce ou s tr iq ue tro rh ab du lu s c ar ita nu s z on e (n n 1) 14g003a* 1 1 33 1 1 2 67 14g003b 1 1 100 14g003c 1 1 2 4 57 2 2 29 1 1 14 14g004b 50 50 100 14g004c 1 1 50 1 1 50 14g004d 1 1 50 1 1 50 14g004e* sterile 14g004f 1 1 100 14g002a* sterile 14g002b sterile 14g002c sterile 14g006a sterile 14g006b* sterile 14g006c* sterile table 2. list of calcareous nannofossil species distribution, counts and percentages in the arapdere section (* indicates thin section nannofossil data). b io zo n e sa m pl es b. b ig el ow ii c . m io pe la gi cu s c . p el ag ic us c . a bi se ct us c . fl or id an us d . d ru gg ii r. b is ec ta r. g el id a r. h aq ii r. m in ut a r. p ro du ct a s. c om pa ct us s. d is si m ili s s. m or ifo rm is t. h ei m ii t. c ar in at us ∑ c oe va l l ow er m io ce ne % a ut oc ht on ou s b. b ig el ow ii c . e op el ag ic us c . p el ag ic us d . b ar ba di en si s d . k ue pp er i e. o va lis r. h es sl an di i s. m or ifo rm is z. b iju ga tu s ∑ re w or ke d eo ce ne % re w or ke d eo ce ne t. sa xe a ∑ re w or ke d pa le oc en e % re w or ke d pa le oc en e m ic ul a sp . m . m ur us m . s ta ur op ho ra ∑ re w or ke d c re ta ce ou s % re w or ke d c re ta ce ou s n n 3 14k007 2 6 2 10 62 2 2 14 4 4 25 bi003a 1 2 4 2 4 13 38 1 14 4 2 21 62 bi003b* 1 2 3 100 14k006 2 2 2 2 1 1 10 100 14k004 2 2 6 2 4 2 6 24 75 2 2 2 6 19 2 2 6 14k005 12 6 15 8 5 2 22 70 97 2 2 3 n n 2 bi001a* 2 1 1 1 9 14 93 1 1 7 bi001b 1 1 2 67 1 1 33 bi001c 1 1 1 1 1 3 1 1 3 13 87 1 1 2 13 n n 1 14k001a 2 6 3 12 18 2 6 2 11 16 2 80 100 14k001b 2 2 2 1 7 58 2 2 1 5 42 g eo lo gi a c ro at ic a geologia croatica 71/3128 type locality: arapdere section remarks on assemblages: discoaster druggii, reticulofenestra haqii, coccolithus miopelagicus and sphenolithus moriformis are present. apart from the samples of the measured section, triquetrorhabdulus challengeri were identified in the mudstone spot sample bi016d. 4.1.4. sphenolithus belemnos zone (nn3) definition: lo of triquetrorhabdulus carinatus to lo of sphenolithus belemnos authors: bramlette & wilcoxon (1967) age: burdigalian, early miocene type locality: arapdere section and abidinoğlutaşı tepe section remarks on assemblages: sphenolithus belemnos, s. disbelemnos, s. compactus and s. conicus are considered as marker species in this zone. 4.2. assemblage composition 4.2.1. necibin tepe section in this section fourteen samples were studied and half of them were sterile. the following species were identified: sphenolithus figure 12. thin section images with reworked nannofossil taxa in the matrix of sandstones 1-4) r. hesslandii, (arapdere section, sample bi001a) 5-6) s. moriformis, (arapdere section, sample bi001a), 7-8) c. pelagicus (arapdere section, sample bi001a), 9-10) c. floridanus (abidinoğlutaşı tepe section, sample 14g0013a) (pl: polarized light, cl: phase contrast, ql: with quartz wedge, gl: with gypsum wedge). g eologia c roatica yavuzlar and sagular: revised chrono-biostratigraphy of lower miocene deposits of the eastern mediterranean (sw turkey) ... 129 compactus, s. moriformis and thoracosphaera heimii. almost half of the assemblage contains reworked specimens from the eocene: reticulofenestra hesslandii, t. saxea and from the cretaceous: micula murus and watznaueria barnesiae (table 1). above 60 m in the section, deposits turn to the 4a rhythmic sandstone-mudstone facies of the güneyce formation defined in calcareous nannofossil nn1, nn2 and nn3 zones at the arapdere section. below 60 m in the section, sediments contain only very sparse miocene sphenolithus compactus, the first appearance of which is also observed in the nn1 zone (perch-nielsen (1985) and aubry (1989)) in the autochthonous nannofossil assemblage with 33 to 67% reworked nannofossils from the cretaceous and 33 – 100% from the lutetian (fig. 7). this section is very close to the arapdere section (fig. 2) and it is positioned at the base of the arapdere section. 4.2.2. arapdere section from a total of eleven samples, two were thin-sections and contain reworked nannofossil taxa. these samples contain: braarudosphaera bigelowii, coccolithus miopelagicus, c. pelagicus, cyclicargolithus abisectus, c. floridanus, discoaster druggii, reticulofenestra bisecta, r. gelida, r. haqii, r. minuta, r. producta, s. compactus, s. dissimilis, s. moriformis, t. heimii and t. carinatus. the reworked assemblage from the eocene contains: b. bigelowii, c. eopelagicus, c. pelagicus, discoaster barbadiensis, d. kuepperi, e. ovalis, r. hesslandii, s. moriformis, z. bijugatus. t. saxea is determined as reworked from the paleocene. the reworked cretaceous nannofossils are micula sp., m. murus and m. staurophora (table 2). in the samples of the arapdere section, the nn1 zone contains 28% autochthonous and 72% reworked nannofossils. the nn2 zone contains from 50 to 60% autochthonous and 40 to 50% reworked forms. the nn3 zone includes 58 to 98% autochthonous forms and between 2 and 42% reworked nannofossil taxa (fig. 8). 4.2.3. abidinoğlutaşı tepe section of nine samples studied, five were thin sections and two were sterile smear slides. the autochthonous species are c. miopelagicus, c. pelagicus, c. floridanus, d. druggii, r. bisecta, r. haqii, sphenolithus belemnos, s. disbelemnos, s. compactus, s. conicus, s. dissimilis, s. moriformis, t.heimii. the reworked species are as follows from the eocene: chiasmolithus solitus, coccolithus formosus, c. pelagicus, discoaster lodoensis, d. mohleri, d. saipanensis, ericsonia robusta, e. subpertusa, pyrocyclus inversus, reticulofenestra dictyoda, s. moriformis, s. radians, s. spiniger and z. bijugatus. paleocene taxa include: t. saxea and from the cretaceous, the following were determined: calculites obscurus, lucianorhabdus cayeuxii, m. murus, m. staurophora and watznaueria barnesiae. in samples 14g017b, 14g018b and 14g016b ascidian spicules were observed (table 3). the autochthonous species belonging to the nn3 zone display percentages from 50 to 73% and reworked species comprise 27 to 50% of the assemblage (fig. 9). 5. discussion 5.1. biostratigraphy and palaeoecology previous studies in this region were undertaken by görmüş et al. (2001) who first identified the nn1 and nn2 zones. the nn1 zone was defined by the presence of: c. floridanus, c. abisectus, c. pelagicus, discoaster deflandrei, d. bisectus, helicosphaera obliqua, s. conicus, s. compactus, s. dissimilis and z. bijugatus. the nn2 zone was defined by the presence of discoaster drug-ta bl e 3. l ist o f c al ca re ou s n an no fo ss il sp ec ie s d ist rib ut io n, c ou nt s a nd p er ce nt ag es in th e ab id in oğ lu ta şı te pe se ct io n (* in di ca te s t hi n se ct io n na nn of os sil d at a) . biozone species c. miopelagicus c. pelagicus c. abisectus c. floridanus d. druggii r. bisecta r. haqii s. belemnos s. disbelemnos s. conicus s. compactus s. dissimilis s. moriformis t. heimii ∑ coeval lower miocene % autochtonous c. solitus c. formosus c. pelagicus d. lodoensis d. mohleri d. saipanensis e. robusta e. cf. subpertusa p. inversus r. dictyoda s. moriformis s. radians s. spiniger z. bijugatus ∑ reworked eocene % reworked eocene t. saxea ∑ reworked paleocene % reworked paleocene c. obscurus l. cayeuxii m. murus m. staurophora w. barnesiae ∑ reworked cretaceous % reworked cretaceous ascidian spicule nn314 g 01 7a * st er il e 14 g 01 7b 1 12 3 1 5 18 1 1 1 11 6 60 76 4 5 3 3 2 2 3 18 23 1 1 1 5 14 g 01 8a * st er il e 14 g 01 8b 3 6 3 3 3 3 8 5 5 39 59 3 8 3 3 3 1 21 29 3 5 8 12 3 14 g 01 3a * 1 3 4 44 5 5 56 14 g 01 3b 24 64 32 40 1 1 1 9 10 84 26 6 80 3 16 10 20 16 65 20 1 1 0 14 g 01 3c * 1 1 10 0 14 g 01 6a 3 8 11 44 1 1 4 13 13 52 14 g 01 6b * 1 1 8 3 1 1 4 9 76 1 1 8 1 1 8 1 g eo lo gi a c ro at ic a geologia croatica 71/3130 gii, d. deflandrei, c. floridanus, c. abisectus, calcidiscus sp, and s. dissimilis. these zones are very diverse and were determined in relatively deeper marine environments than presented here. in this region, the nn3 zone was first described by hepdeni̇z & sagular (2009), defined by the presence of triquetrorhabdulus carinatus, discoaster cf. druggii, sphenolithus belemnos, dictyococcites perplexus, pyrocyclus cf. orangensis, reticulofenestra haqii, sphenolithus compactus, sphenolithus conicus, coccolithus miopelagicus. a general distinction of autochthonous and reworked nannofossil taxa allows the definition of depositional and paleoenvironmental characteristics and leads to more reliable sedimentary and stratigraphic interpretations, especially for a fluctuating and unfavourable coastal environment (sagular, 2003a, b). in this type of environment, marine deposits, such as the güneyce formation, generally contain very low amounts of autochthonous nannofossil assemblages. reworked nannofossil assemblages are predominant in the sediments of the güneyce formation (tables 1, 2 and 3). while autochthonous nannofossils display percentages between 33 and 100%, the reworked taxa account for between 6 and 100% of the assemblage composition. based on the generally very high percentages of reworked taxa in the assemblages the güneyce formation can be interpreted as representing a very shallow marine environment (figs. 7, 8 and 9). the calcareous nannofossil assemblages of the güneyce formation, are dominated by the sphenolithus genus, as being more common in lower latitudes, preferring warm and shallow waters than open ocean (perch–nielsen 1985b). according to wei figure 13. thin section images of sandstones with reworked nannofossil taxa 1-2) c. solitus in lithoclast (abidinoğlutaşı tepe section, sample 14g0013a), 3-4) r. hesslandii in matrix (necibin tepe section, sample 14g003a); 5-8) c. pelagicus in matrix, and 5-7 & 9) c. pelagicus in matrix (abidinoğlutaşı tepe section, sample 14g013a) (pl: polarized light, cl: phase contrast, ql: with quartz wedge, gl: with gypsum wedge). g eologia c roatica yavuzlar and sagular: revised chrono-biostratigraphy of lower miocene deposits of the eastern mediterranean (sw turkey) ... 131 figure 14. thin section images of sedimentary structures in sandstone sample 14g0016b of the abidinoğlutaşı tepe section 1) general view of the sandstone, 2-3) isopachous rim cement and ascidian spicule enclosed in intergranular sparry calcite cement of an intertidal sandstone, 4-6) neomorphic fibrous fine crystalline spherulite flügel (1982). g eo lo gi a c ro at ic a geologia croatica 71/3132 & wise (1990) sphenolith diversity is higher in equatorial sites, being less diverse in the mid-latitude areas. only s. moriformis existed in the high-latitude sites. within the whole asemblage, 150 individuals were counted and s. moriformis is presented here as the most abundant species. based on the work of the aforementioned authors sphenolithus spp. abundance and diversity indicate a shallow marine environment of the mid-latitudes. 5.2. necibin tepe section the clastic levels in approximately the first 44 m of the section have no nannofossil data due to a prevailing terrestrial or shoreline environment (figure 4, table 1). from 44 m 60 m, the presence of gypsum and microalgal (derived from dinoflagellate cysts) sapropelic coal lenses can be observed in the muddy levels of the succession. due to the presence of such coal (fig. 11) and gypsum lenses in the samples of the necibin tepe section, it is considered that the early miocene sedimentation was started in terrestrial and continued to occur in a littoral environment (fig. 7). besides, nannofossil data indicate the nn1 biozone, this section includes the beginning of the early miocene sedimentation of the güneyce formation. 5.3. arapdere section depending on the original distribution of nannofossil assemblages within the miocene to cretaceous (table 2), the arapdere section represents transgressive shallow marine sediment levels in the güneyce formation. they include beach sediments or shoreline sandstones representing shallow marine environments such as littoral, tidal or the offshore-transitional zone or clastic shelf and contain mudstones with low coeval nannofossil contents. the distribution of autochthonous and reworked nannofossils in rock samples indicate sea level fluctuations in the early miocene shoreline transgression (figs. 8 and 12). 5.4. abidinoğlutaşı tepe section according to the nannofosil records of the abidinoğlutaşı tepe section, autochthonous nannofossil species decrease from the bottom levels and then become dominant again in the upper parts of the section (fig. 9, table 3). the interpretation of this section is that the sediments of these levels represent shallow marine depositional environments. additionally, the presence of ascidian spicules in the samples 14g017b, 14g018b and 14g016b (table 3) can be considered as an indicator of a shallow environment (van name, 1945). from the bottom to the top of the section, the transgressive character and sea level fluctuations continue throughout. the proportions of autochthonous and reworked nannofossil assemblages in the samples of the abidinoğlutaşı tepe section indicate a generally transgressive trend with unstable sea level change observed in a very shallow coastal environment during the burdigalian after the beginning of the miocene (figs. 9, 13 and 14). based on the new results, in addition to previous studies in the southern part of isparta (görmüş et al., 2001; hepdeni̇z & sagular, 2009), the marine carbonate and clastics of the isparta formation were deposited during the lutetian and the shallow marine shelf clastics of the güneyce formation were deposited during the lower miocene. 6. conclusions the following nannofossil biozones are represented in this study: the np16 discoaster tanii nodifer zone, which was defined in the isparta formation and three zones in the lower miocene: the nn1 triquetrorhabdulus carinatus zone, nn2 discoaster druggii zone and nn3 sphenolithus belemnos zone in the güneyce formation. based on the high amount of reworked nannofossil species the güneyce formation was probably deposited in a shallow marine environment. the map of the study area was refined and two marine clastic sedimentary units were revised and described (the isparta and güneyce formations). an ophiolitic melange (gökçebağ melange) was illustrated in regional maps in former studies as having been thrust over all the sedimentary sequence, in this study the map is modified according to the presented results. marine clastic sediments unconformably overlie the ophiolitic melange. in addition, the 3d geologic map of the study area is revised and presented here. acknowledgment the data of this study supported by the bap 3913-yl1-14 project of süleyman demirel university. the authors are thankful to madalina-elena kallanxhi (babeș–bolyai university, romania) for suggestions and comments on the manuscript and would also like to thank two anonymous reviewers for their comments and helpful suggestions. references akbulut, a. (1980): eğirdir gölü güneyinde çandır (sütçüler-isparta) yöresindeki batı torosların jeolojisi [the geology of the western taurids in the area of çatıdır (sütçüler, i̇sparta), south the eğridir lake – in turkish, with an english abstract].– bulletin of geological society of turkey, 23/1, 1–9. aubry, m.p. (1989): handbook of cenozoic calcareous nannofossils, book 3.– new york: micropaleontology press, 279 p. barrier, e. & vrielynck, b. (2008): map 12. early burdigalian (20.4-17.4 ma), in palaeotectonic maps of the middle east: tectono-sedimentary-palinspastic maps from late norian to pliocene, commission for the geological map of the world. bown, p.r. & newsam, c. (2017). calcareous nannofossils from the eocene north atlantic ocean (iodp expedition 342 sites u1403–1411).– journal of nannoplankton research, 37/1, 25–60. bown, p.r. & young, j.r. (1998): techniques. in: bown p.r. (ed.): calcareous nannofossil biostratigraphy.− kluwer academic publications, dordrecht, 16–28. doi: 10.1007/978–94–011–4902–0_2 bramlette, m.n. & wilcoxon, j.a. (1967): middle tertiary calcareous nannoplankton of cipero section, trinidad, w. i. tulane stud. geol., 5, 93–131. flügel, e. (1982): microfacies analysis of limestones.− translated by k. chresresen, springer-verlag, berlin, 633 p. doi: 10.1007/978-3-642-68423-4 görmüş, m. & özkul, m. (1995): gönen-atabey (isparta) ve ağlasun (burdur) arasındaki bölgenin stratigrafisi [stratigraphy of gönen-atabey (isparta) and aǧlasun (burdur)– in turkish, with an english abstract].– suleyman demirel university journal of science institute, 1, 43–64, isparta. görmüş, m., sagular, e.k. & çoban, h. (2001): the miocene sequence characteristics, its contact relation to the older rocks and lamprophyric dikes in the dereboğazı area (southern isparta, turkey).− proceedings of the 4th international symposium on eastern mediterranean geology, isparta, 69–90. görmüş, m., sagular, e.k., bozcu, a., uysal, k. & poisson, a. (2004): why is reworking important? an example from the cretaceous and tertiary sediments around isparta (sw turkey).− proceedings of the 4th international congress ‘environmental micropaleontology, microbiology and meiobenthology’, isparta, 84–87. gutnic, m., monod, o., poisson, a. & dumont, j.f. (1979): geologie des taurides occidentales (turquie).− memories société géologique de france, 137, 1–112. hepdeni̇z, k. & sagular, e.k. (2009): direkli ve darıdere köyleri (isparta güneyi) yöresindeki tersiyer yaşlı denizel kırıntılılarının nannofosil verilerinin kökensel ayırımına dayanan stratigrafik çözümlemesi [stratigraphical analysis based upon generic discrimination of the nannofossil data of the tertiary-aged marine clastics around the district of direkli and darıdere villages (south of isparta) – in turkish, with an english abstract].– suleyman demirel university journal of science institute, 13/3, 245–264. karaman, m.e. (1990): isparta güneyinin temel jeolojik özellikleri [basic geological characteristics of southern i̇sparta – in turkish, with an english abstract].– geological bulletin of turkey, 33, 57–67. karaman, m.e. (1994): isparta-burdur arasının jeolojisi ve tektonik özellikleri [geology and tectonic features between i̇sparta and burdur area (sw turkey) – in turkish, with an english abstract].– geological bulletin of turkey, 37/2, 119–134. martini, e. (1971): standard tertiary and quaternary calcareous nannoplankton zonations.– in: farinacci, a. (ed.): proceedings 2nd international conference on planktonic microfossils, roma 1970. rome ed. tecnoscienza, 2, 739–785. g eologia c roatica yavuzlar and sagular: revised chrono-biostratigraphy of lower miocene deposits of the eastern mediterranean (sw turkey) ... 133 martini, e. & worsley, t. (1970): standard neogene calcareous nannoplankton zonation.– nature, 225, 289–90. doi: 10.1038/225289a0 martini, e. & müller, c. (1986): current tertiary and quaternary calcareous nannoplankton stratigraphy and correlations.− newslett. stratigr., 16/2, 99–112. doi: 10.1127/nos/16/1986/99 melinte, c.m. (2004): calcareous nannoplankton, a tool to assign environmental changes.− article in geo-eco-marina, doi: 10.5281/zenodo.57517 perch-nielsen, k. (1985a): mesozoic calcareous nannofossils.– in: bolli, h.m., saunders, j.b. & perch-nielsen, k. (eds.): plankton stratigraphy volume 1. cambridge university press, cambridge, 329–426. perch-nielsen, k. (1985b): cenozoic calcareous nannofossils.– in: bolli, h.m., saunders, j.b. & perch–nielsen, k. (eds.): plankton stratigraphy.– cambridge university press, 427–554. poisson, a., yağmurlu, f., bozcu, m. & sentürk, m. (2003): new insights on the tectonic setting and evolution around the apex of the isparta angle (sw turkey).− geological journal, 38/3–4, 257–282. doi: 10.1002/gj.955 robertson, a.h.f., poisson, a. & akinci, o. (2003): developments in research concerning mesozoic-tertiary tethys and neotectonics in the isparta angle, sw turkey.− geological journal, 38/3–4, 195–234. doi: 10.1002/gj.953 sagular, e.k. (2003a): nannofosil verilerinin stratigrafik yaş ve ortamsal yorumlarda kullanımına ilişkin yeni bir inceleme yöntemi [a new determination method on using nannofossil data in stratigraphic ageing and paleoenvironmental analyses – in turkish, with an english abstract].– suleyman demirel university journal of science institute, special issue, 7/2, 25–36. sagular, e.k. (2003b): denizel kırıntılı kayaçlarda, eşyaşlı veya yeniden çökelimin nannofosil tanımlamalarına dayanan sayısal analizi [discriminate analysis of synsedimentation or reworking in marine clastic sedimentary rocks based on nannofossil determinations – in turkish, with an english abstract].– turkish association petroleum geologists bulletin, 15/2, 75–107. şenel, m. (1997): 1:100000 ölçekli türkiye jeoloji haritaları no: 13, isparta-j10 paftası [in turkish].– publication of mineral research and exploration institute, department of geological research, ankara, turkey, 26 p. van name, w.g. (1945): the north and south american ascidians.– bull. am. mus. nat. hist., 84, 1–476. wade, b.s. & bown, p.r. (2006): calcareous nannofossils in extreme environments: the 1352 messinian salinity crisis. polemi basin, cyprus.− palaeogeogr. palaeoclimatol. 1353 palaeoecol., 233/3–4, 271–286. doi: 10.1016/j.palaeo.2005.10.007 wei, w. & wise, s.w.jr. (1990): biogeographic gradients of middle eocene–oligocene calcareous nannoplankton in the south atlantic ocean.− palaeogeogr. palaeoclimatol. palaeoecol., 79/1–2, 29–61. yağmurlu, f. (1994): isparta güneyinde yeralan tersiyer yaşlı türbiditik birimlerin fasiyes özellikleri [in turkish].– geosound, 24, 17–28. yavuzlar, g. (2015): burdur ve isparta arasında bulunan geç tersiyer denizel tortul kayaçlarının nannofosillerle krono-biyostratigrafik çözümlenmesi [chronobiostratigraphical analysis based on nannofossils of late tertiary marine sedimentary rocks located between burdur and isparta – in turkish, with an english abstract].– süleyman demirel university, natural and applied sciences institute, master thesis, 102 p. yavuzlar, g. & sagular, e.k. (2017): burdur ve isparta arasında bulunan üst tersiyer denizel tortul kayaçlarının nannofosillerle biyostratigrafik çözümlenmesi [biostratigraphical analysis based on nannofossils of upper tertiary marine sedimentary rocks located between burdur and isparta – in turkish, with an english abstract].– suleyman demirel university, journal of natural and applied sciences, volume 21, issue 1, 79–87. young, j.r. (1998): neogene.– in: bown, p.r. (ed.): calcareous nannofossil biostratigraphy. kluwer academic publications, dordrecht, 225–265. doi: 10.1007/978– 94–011–4902–0_8 young, j.r, bown, p.r. & lees, j.a. (2013): nannotax website.– international nannoplankton association (2013). list of calcareous nannofossil taxa miocene nannofossil taxa: coccolithus miopelagicus bukry cyclicargolithus abisectus (müller) wise cyclicargolithus floridanus (roth & hay) bukry discoaster druggii bramlette & wilcoxon reticulofenestra bisecta (hay, mohler & wade) roth reticulofenestra haqii backman reticulofenestra minuta roth reticulofenestra producta (kamptner) wei & thierstein reticulofenestra pseudoumbilicus (gartner) gartner sphenolithus belemnos bramlette & wilcoxon sphenolithus compactus backman sphenolithus conicus bukry sphenolithus disbelemnos fornaciari & rio sphenolithus dissimilis bukry & percival sphenolithus moriformis (bronnimann & stradner) bramlette & wilcoxon thoracosphaera heimii (lohmann) kamptner triquetrorhabdulus carinatus martini triquetrorhabdulus challengeri perch-nielsen palaeogene nannofossil taxa: blackites inversus (bukry & bramlette) bown & newsam chiasmolithus gigas (bramlette & sullivan) radomski chiasmolithus solitus (bramlette and sullivan) locker coccolithus eopelagicus (bramlette & riedel) bramlette & sullivan coccolithus formosus (kamptner) wise coccolithus pelagicus (wallich) schiller discoaster barbadiensis tan discoaster deflandrei bramlette & riedel discoaster kuepperi stradner discoaster lodoensis bramlette & riedel discoaster mohleri bramlette & percival ericsonia robusta (bramlette & sullivan) edwards & perch-nielsen discoaster saipanensis bramlette & riedel ericsonia subpertusa hay & mohler reticulofenestra dictyoda (deflandre in deflandre & fert) stradner reticulofenestra gelida (geitzenauer) backman reticulofenestra hesslandii (haq) roth sphenolithus moriformis (bronnimann & stradner) bramlette & wilcoxon sphenolithus radians deflandre sphenolithus spiniger bukry thoracosphaera heimii (lohmann) kamptner thoracosphaera saxea stradner zygrhablithus bijugatus (deflandre) deflandre mesozoic nannofossil taxa: calculites obscurus (deflandre) prins & sissingh in sissingh lucianorhabdus cayeuxii deflandre micula vekshina micula murus (martini) bukry micula staurophora (gardet) stradner thoracosphaera heimii (lohmann) kamptner watznaueria barnesiae (black) perch-nielsen 2020 | 73/2 | 95–106 | 7 figs. | appendix www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction although tropical mesozoic carbonate platform successions in the peri-adriatic region (figs. 1a, b) are characterized by a hiatus that encompasses the cretaceous–palaeogene (k–pg) boundary (eberli et al., 1993; bosellini et al., 1999; vlahović et al., 2005; korbar, 2009), there are rare outcrops characterized by a more or less continuous record of the stratigraphic interval of global interest (korbar, 2019, and references therein). the adriatic-dinaridic carbonate platform (adcp cf. pamić et al., 1998) that was separated into two major segments: adriatic carbonate platform (acp) and dinaridic carbonate platform (d’argenio et al., 1971; korbar, 2009; figs. 1a, b), also recognized as a unified adriatic carbonate platform (adcp cf. vlahović et al., 2005; fig. 1c), was the largest mesozoic neritic depositional system in the region. because of a regional emergence of the platform during the late cretaceous into the palaeogene, and the related hiatus within the succession, only a few exceptional localities from the central part of the adriatic carbonate platform sensu stricto (acp cf. korbar, 2009) are characterized by a more or less continuous sedimentary record across the k–pg boundary. this boundary is marked within the sections by a deposit which is a few centimetres to a few metres thick, inter preted as the k–pg tsunamite (korbar et al., 2015, 2017a). the contact of the upper cretaceous and palaeogene limestones on the island of biševo (fig. 1c) is characterized by ap maastrichtian to palaeocene and eocene pelagic carbonates on the island of svetac (central adriatic, croatia) tvrtko korbar1*, ladislav fuček1, vlasta premec fućek2 and nenad oštrić1 1 croatian geological survey, department of geology, sachsova 2, hr-10000 zagreb, croatia; (*corresponding author: tkorbar@hgi-cgs.hr) 2 ina-industrija nafte d.d., lovinčićeva 4, hr-10000 zagreb, croatia doi: 10.4154/gc.2020.07 abstract maastrichtian to palaeocene pelagic carbonates on the central adriatic island of svetac (sveti andrija) are the only outcrops reported to date that document pelagic deposition during the cretaceous–palaeogene (k–pg) transition within the adriatic basin. an approximately 3 m thick succession at the smokvica locality contains a rich and diverse planktonic foraminiferal assemblage which allows dating of the succession and the recognition of some biostratigraphic zones. the lower part of the smokvica section consists of 1.5 m thick pelagic biomicrite characterized by the abundance of late maastrichtian planktonic foraminifera that indicate the abathomphalus mayaroensis zone. an intercalation of intraclastic floatstone <0.5 m in thickness occurring on top of maastrichtian pelagic biomicrite is characterized by unsorted pelagic intraclasts floating within the pelagic matrix, and both components only contain maastrichtian planktonic foraminifera. the floatstone is overlain by another <0.5 m thick intraclastic-bioclastic floatstone characterized by rounded pelagic intraclasts (plasticlasts) containing maastrichtian planktonic foraminifera floating in the pelagic matrix. the matrix of the later floatstone contains maastrichtian and palaeocene planktonic foraminifera mixed together. thus, the transition from the maastrichtian to the palaeocene is not continuous but is characterized by amalgamated debrites that are related to at least two separated re-depositional events within the basin. the overlying pure pelagic biomicrite is rich in planktonic foraminifera that indicates the palaeocene p3 zone. a few metres apart, after the covered interval, there are also eocene pelagic biomicrites with planktonic foraminifera which indicate the eocene e9 zone, characterized by the co-appearance of benthic foraminifera (discocyclina) floating within the pelagic matrix. it is assumed that a maastrichtian opening of the deep-water environment connected to the adriatic basin within the former adriatic carbonate platform west of the island of vis could be related to a re-activation of an inherited transverse fault zone. proximately 50 million years of non-deposition and erosion (korbar et al., 2012) which is typical for the outermost acp tectonostratigraphic unit i.e., the istrian karst (korbar, 2009). the k–pg hiatus within the shallow-water succession is also recognized in the boreholes located to the southeast of the island of svetac (sveti andrija), while to the southwest there is the realm of the adriatic basin (grandić et al., 1999, 2002; fig. 1c). the k–pg transition within the central part of the adriatic basin is penetrated by the koraljka borehole (125 km nw of the island of svetac; fig. 1c) is characterized by pelagic chalky limestones with bioclastic (allodapic) platform-derived intercalations (lučić et al., 1993). deeper-water carbonates deposited within the adcp intraplatform basins were characterized by calcisphere wackestonepackstones with rare planktonic foraminifera, indicating a restricted connection with the open sea (gušić & jelaska, 1990; fuček et al., 1991). the openings and durations of the intra-platform basins were diachronous, within the range from the turonian to the campanian, while the maastrichtian was generally characterized by platform emergence, although peritidal deposition occurred within distinct tectonostratigraphic units of the acp (korbar, 2009). most of the data on the stratigraphy and palaeoenvironments along the buried acp margin and the adriatic basin in the cenarticle history: manuscript received january 17, 2020 revised manuscript accepted may 06, 2020 available online june 30, 2020 keywords: adriatic platform and basin, cretaceous, palaeogene, planktonic foraminifera mailto:lfucek@hgi-cgs.hr g eo lo gi a c ro at ic a geologia croatica 73/296 2. geological setting the central adriatic area belongs to the central part of the adriatic microplate (adria) that has been affected by a very complex mesozoic to cenozoic geodynamic evolution characterizing the peri-adriatic region (channell et al., 1979; rosenbaum et al., 2004; schmid et al., 2008). the evolution was recorded within a sedimentary succession several kilometres thick starting from the triassic rifting phase of pangea to the latest stage of the alpine orogeny, when the orogenic belts developed along the circum-adriatic margins (fig. 1a). seismic data and deep wells revealed a thick pile of mesozoic to quaternary sediments that are in places tectonically disturbed mostly by salt diapirs that contain incorporated middle to upper triassic magmatic rocks (grandić et al., 1999, 2002; geletti et al., 2008; korbar, 2009). the diapirs were driven by mobilized middle triassic salt that in places pierced the sedimentary succession and appears at the surface (belak et al., 2005; korbar et al., 2012). the ditral adriatic area have been collected for the oil industry, and are synthesised in the published papers (grandić et al., 1999; vlahović et al., 2005; korbar, 2009). grandić et al. (1999) interpreted the acp margin as lying some 20 km sw of the island of svetac, along a rather complex tectonic system characterized by salt diapirs (geletti et al., 2008). although korbar et al. (2012) show only shallow-water cretaceous carbonates on the island (fig. 1c), new more detailed investigations revealed important data on pelagic sedimentation during the latest cretaceous to palaeogene period. the aim of this paper is to document deep-water pelagic facies on the island of svetac. the facies is important for re-interpretation of the local palaeogeography and for the evolution of depositional environments in this part of the central adriatic at the end of the mesozoic (fig. 1c), as well as for future reconstruction of the western tethys palaeogeography during the transition from the late cretaceous to the early palaeogene. figure 1. location map of the island of svetac (arrows) on: a) a peri-adriatic geotectonic sketch (after korbar, 2009); b) a peri-adriatic palaeogeographic map sketch showing the existence of two segments of the adcp domain: the adriatic and dinari dic (modified after korbar, 2009 and korbar, 2019); c) the adriatic carbonate platform (adcp) domain (light grey, modified after vlahović et al., 2005) along the northeastern adriatic coast (major croatian islands and towns are indicated). g eologia c roatica korbar et al.: maastrichtian to palaeocene and eocene pelagic carbonates on the island of svetac (central adriatic, croatia) 97 apirs outcropped presumably during the miocene (pikelj et al., 2015), and are still growing (geletti et al., 2008; babić et al., 2012). thus, salt tectonic related deformations of the overlying adriatic carbonate platform succession and quaternary erosion created prominent geological structures and interesting geomorphological features of the central adriatic islands (korbar et al., 2012), that have been recognized recently as unesco global geopark vis archipelago. the island of svetac is the outermost island of the central adriatic (dalmatian) archipelago, located about 50 km south of the mainland, and 22 km west of the island of vis (fig. 1c). palaeogeographically, the island of svetac is considered to be an integral part of the adriatic carbonate platform (vlahović et al., 2005), and is at the surface built of tectonic blocks derived from a >1500 m thick succession of typical cretaceous shallowwater (neritic) carbonates (korbar et al., 2012). the wider area of the island belongs to the adriatic foreland of both the dinarides and the apennines (scisciani & calamita, 2009; fig. 1a). the cretaceous to palaeogene dinaric forebulge stage and the long-lasting subaerial exposure of the platform was followed by deposition during the oligocene foreland stage at the end of the dinaric foredeep migration phase (korbar, 2009). the upper cretaceous rudist-bearing carbonates outcropping on the island of svetac is recognized as a typical acp succession of the gornji humac formation (gušić & jelaska, 1990), although the uppermost part resembles the open-platform and slope carbonates reported from the acp domain: the turonian carbonates in the western part of the island of dugi otok (fuček et al., 1991), the turonian–santonian of the islands of premuda, ist and silba (moro & ćosović, 2013), or the middle campanian facies on the islands of brač (cvetko tešović et al., 2001; steuber et al., 2005) and hvar (korbar et al., 2010). the gornji humac formation on the island of svetac, outcropping on the south-eastern coasts of the island (slatina locality, fig. 2), is characterized by recrystallized medium to thick-bedded limestones with typical peritidal rudist lithosomes composed of various radiolitid rudists. in contrast, the northern and western outcrops referred to as the gornji humac formation are built of recrystallized thick-bedded to massive bioclastic limestones rich in rudist fragments and recrystallized biomicrite. the carbonates are in distinct tectonic contacts with the lower cretaceous peritidal carbonates of the goveđari and babino polje formations (husinec, 2002) from the south and from the north, respectively (korbar et al., 2012; fig. 2 and 2/ supplement – appendix). 3. materials and methods the first discovery of the pelagic facies on the island of svetac was in 2005, documented by the analyses of the sample from the observation point vn-214 (wgs: 15.762892e, 43.026051n; htrs (e/n): 439927/4765401). in 2014, focused mapping was performed for the purpose of defining the spatial distribution of the pelagic facies. the narrow zone of pelagic carbonates strikes east-west and is bordered by distinct and indistinct faults. the carbonates were partly covered by colluvium in crna ploča cove, along a major fault that borders the zone from the north (figs. 2 and 2/supplement – appendix). because of the faults and indistinct bedding (it seems that the bedding within the tectonic block is nearly vertical), it was possible to measure and sample only one section along the narrow pedestrian trail in the smokvica area (fig. 2). the section extends from the southwest where it is in tectonic contact with predominantly bioclastic recrystallized carbonates containing radiolitid rudist bioclasts, to the northeast figure 2. geological map of the island of svetac (korbar et al., 2012), showing the position of the studied section vss and sample vn-214 at smokvica locality (black arrow) within a narrow zone of maastrichtian to palaeogene thick-bedded to massive pelagic carbonates (hatched). g eo lo gi a c ro at ic a geologia croatica 73/298 where it is in tectonic contact with the zone of maastrichtian pelagic biomicrites (fig. 2). the smokvica section is measured and sampled within the zone of massive pelagic carbonates, starting from sample vss-1 (wgs: 15.762634e, 43.026043n; htrs (e/n): 439905/4765400) to sample vss-4 (wgs: 15.762635e, 43.026076 n; htrs (e/n): 439905/4765404), and, a few metres north of the covered part (fig. 3), to sample vss-5 (wgs: 15.762635e, 43.026106 n; htrs (e/n): 439906/4765407). the preliminary palaeontological and facies observations were undertaken in the field by hand lens. thin-sections were prepared at the croatian geological survey according to the standard procedure for microfacies and micropaleontological analyses (flügel, 2010). the optical microscopy and photomicrographs of the selected thin-sections were taken by an olympus szx12. the taxonomic determinations of planktonic foraminifera were based on un-oriented cross sections of the foraminiferal tests and observations of the morphological characteristics such as the size and the shape of the test, size, shape, number and arrangements of chambers, thickness of the wall, presence or absence, position and number of peripheral thickenings or keels. the species concept for cretaceous taxa after sliter (1989) and premoli silva & verga (2004) was used, together with the papers of sari (2006, 2009). palaeocene and eocene species were determined after olsson et al. (1999), premoli silva et al. (2003), and pearson et al. (2006). the foraminifera sections of young et al. (2017) has also been used. 4. results the research resulted in discovery of the pelagic thick-bedded to massive carbonates in the crna ploča cove (figs. 2, 2/supplement – appendix, 3, and 4). these are predominantly mudstones to skeletal wackestones (rarely floatstones) with intercalations of recrystallized bioclastic packstone to grainstone. fine-grained reddish skeletal wackestones in places resemble typical pelagic facies a biomicrite rich in planktonic foraminifera that lack any benthic fossils. 4.1. cretaceous to palaeogene (k–pg) pelagic carbonates at smokvica the vis-svetac-smokvica (vss) section on the island of svetac is characterized by a ~3 m thick succession of thick-bedded cretaceous and palaeocene pelagic limestones with a few intraclastic and bioclastic intercalations (fig. 3 and 3/supplement – figure 3. illustrated stratigraphic column vis-svetac-smokvica (vss) showing the position of the samples, distribution of the determined fossils, and photographs of polished slabs of intraclastic floatstones (debrites) that mark the contact of maastrichtian and the palaeocene: a) sample vss-3, b) sample vss-3a. g eologia c roatica korbar et al.: maastrichtian to palaeocene and eocene pelagic carbonates on the island of svetac (central adriatic, croatia) 99 appendix). the lower part of the succession is characterized by a 1.5 metre thick package of pelagic limestones (biomicrite) characterized by the mass occurrence of maastrichtian planktonic foraminifera (fig. 5). an intercalation <0.5m thick of intraclastic floatstone is located above the maastrichtian pelagic biomicrite. the intercalation is characterized by unsorted 2−20 mm long light-grey intraclasts of pelagic wackestone to packstone (biomicrite) that are “floating” within the pinkish-grey pelagic wackestone to packstone (polished slab vss-3; figs. 3a and 4). both lithological components contain exclusively maastrichtian planktonic foraminifera (fig. 5). directly overlying the intraclastic floatstone (fig. 3) there is another intraclastic-bioclastic floatstone, (<0.5m thick) characterized by a pelagic matrix and semi-rounded intraclasts (plasticlasts) of similar pelagic facies, along with tiny molluscan bioclasts (polished slab vss-3a on fig. 3b). the floatstone is figure 4. a) composite photomicrograph of the sample vss-3a showing the mixture of palaeocene and maastrichtian pelagic lime mud and intraclasts/plasticlasts (rim of a maastrichtian intraclast is indicated by arrows); b and d) magnified parts of the rim; c and e) magnified maastrichtian planktonic foraminifera from the palaeocene matrix. g eo lo gi a c ro at ic a geologia croatica 73/2100 characterized by 2−20 mm long intraclasts and bioclasts floating in a pelagic wackestone to packstone containing maastrichtian (figs. 5e, g, and h) and palaeocene (fig. 6a−c, and f) planktonic foraminifera in the matrix and in the intraclasts (fig. 4). thus, the palaeocene pelagic floatstone that is characterized by mixed maastrichtian intraclasts and lime mud containing maastrichtian and palaeocene planktonic foraminifera, directly overlies the maastrichtian pelagic floatstone. it should be noted that the lowermost palaeocene (danian) planktonic foraminiferal associations are not observed (fig. 3). the overlying metre thick pelagic limestone only contains palaeocene planktonic foraminifera (figs. 3 and 6d). in the middle part of the limestone there is an intercalation of intraclastic-bioclastic floatstone that contains solely palaeocene pelagic intraclasts. two metres north of the maastrichtian to palaeocene succession (the walking trail is covered by vegetation, fig. 3/supplement – appendix), there is a metre long outcrop of eocene pelagic limestone (figs. 3 and 6) that is characterized by the appearance of palaeogene benthic foraminifera (discocyclinids) floating within the eocene pelagic mudstone (fig. 6o). the eocene pelagic limestone is in tectonic contact with a light-grey maastrichtian pelagic mudstone outcropping north of the fault. figure 5. photomicrographs of selected maastrichtian planktonic foraminifera from sample vn-214 and samples vss 1-3. a – contusotruncana patelliformis, sample vss-2; b – contusotruncana contusa, sample vn-214; c – contusotruncana fornicata, sample vn-214; d – globotruncanita stuarti, sample vss-3; e – globotruncanita insignis, sample vss-3a; f – kuglerina rotundata, sample vn-214; g, h – globotruncanella havanensis, sample vss-3a; i – globotruncanella pschadae, sample vn-214; j – racemiquembelina fructicosa, sample vn-214; k – planoglobulina acervulinoides, sample vss-3; l planoglobulina acervulinoides and fragment of abathomphalus mayaroensis, sample vn-214. all scale bars 0.2 mm. g eologia c roatica korbar et al.: maastrichtian to palaeocene and eocene pelagic carbonates on the island of svetac (central adriatic, croatia) 101 figure 6. photomicrographs of selected palaeogene planktonic foraminifera from samples vss 3a-5. a,b – morozovella angulata, sample vss-3a; c – igorina tadjikistanensis, sample vss-3a; d – subbotina velascoensis, sample vss-4a; e – globanomalina ehrenbergi; sample vss-4; f – parasubbotina pseudobulloides, sample vss3a; g, – turborotalia frontosa, sample vss-5; h – subbotina yeguaensis, sample vss-5; i – morozovelloides crassatus, sample vss-5; j – subbotina eocaena, sample vss-5; k – globigerinatheka kugleri, sample vss-5; l – pseudoglobigerinella bolivariana, sample vss-5a; m – acarinina mcgowrani, sample vss-5; n – acarinina bullbrooki, sample vss-5; o – discocyclinid benthic foraminifera within the pelagic matrix of sample vss-5a. all scale bars 0.2 mm. g eo lo gi a c ro at ic a geologia croatica 73/2102 4.2. biostratigraphy the analysed planktonic foraminifera unambiguously indicate the successive appearance of maastrichtian and palaeocene species within a ~3 m thick succession in the geological column vss (figs. 3 and 3/supplement– appendix). a few metres north of the succession, after a covered interval, there are also pelagic carbonates that contain eocene species. the sample from the observation point vn-214 is observed 20 m east of samples vss-1 and 2, within the same zone of the light-grey pelagic mudstones, and is analyzed here because of the exceptionally well preserved thinsections of maastrichtian planktonic foraminifera. the following maastrichtian taxa have been determined: contusotruncana patelliformis (fig. 5a), globotruncanella havanensis (figs. 5g, h), globotruncanella pschadae (fig. 5i), globotruncanella cf. petaloidea, globotruncana arca, globotruncanita insignis (fig. 5e), globotruncana cf. orientalis, globotruncanita stuarti (fig. 5d), globotruncanita conica, abathomphalus mayaroensis (fig. 5l), kuglerina rotundata (fig. 5f), contusotruncana fornicata (fig. 5c), contusotruncana contusa (fig. 5b), planoglobulina acervulinoides (figs. 5k, l), ventilabrella sp., gublerina sp., racemiguembelina fructicosa (fig. 5j), macroglobigerinelloides sp., muricohedbergella sp., heterohelix sp., pithonella ovalis, p. innominata and p. sphaerica. the assemblage of planktonic foraminifera indicates the late maastrichtian abathomphalus mayaroensis zone (premoli silva & verga, 2004). a mixed assemblage of maastrichtian and palaeocene planktonic foraminifera occurs in sample vss-3a. the following palaeocene taxa have been determined: morozovella angulata (figs. 6a, b), igorina tadjikistanensis (fig. 6c), i. pusilla, subbotina triloculinoides, s. triangularis, parasubbotina pseudobulloides (fig. 6f), globanomalina ehrenbergi (fig. 6e) and globanomalina chapmani. the association is characteristic for the palaeocene p3 zone, i.e. the morozovella angulata lowest occurrence zone, defined as the interval between the lowest occurrence (lo) of morozovella angulata and the lo of globanomalina pseudomenardii (wade et al., 2011). the very rare occurrence of small benthic foraminifera has also been observed. sample vss 4 contains the following planktonic foraminiferal species: morozovella angulata, igorina tadjikistanensis, subbotina velascoensis (fig. 6d), s. triloculinoides, s. triangularis, s. cancellata, globanomalina ehrenbergi and globanomalina chapmani. the planktonic association indicates upper part of the palaeocene p3 zone (morozovella angulata). a rich and highly diverse eocene planktonic foraminiferal association has been observed in samples vss-5 and 5a. species such as turborotalia frontosa (fig. 6g), morozovelloides crassatus (fig. 6i), subbotina yeguaensis (fig. 6h), s. eocaena (fig. 6j), globigerinatheka kugleri (fig. 6k), pseudoglobigerinella bolivariana (fig. 6l), acarinina mcgowrani (fig. 6m) and a. bullbrooki (fig. 6n) are characteristic of the middle eocene e9 zone (globigerinatheka kugleri/morozovella aragonensis) defined as the concurrent range zone of the nominate taxa between the lo of globigerinatheka kugleri and the highest occurrence (ho) of morozovella aragonensis (berggren & pearson, 2005; wade et al., 2011). in addition to the planktonic foraminiferal taxa many specimens of the large benthic foraminifera discocyclina sp. are also present (fig. 6o). 5. discussion the pelagic facies described on the island of svetac do not resemble intra-platform basinal facies reported from elsewhere on the adriatic carbonate platform (acp) domain, that are characterized by a paucity of planktonic foraminifera and an abundance of calcispheres (gušić & jelaska, 1990; fuček et al., 1991). instead, the pelagic carbonates on the island of svetac are rich in various species of planktonic foraminifera, suggesting a direct connection of the depositional environment with the open sea. thus, it is inferred that during the maastrichtian a deep embayment developed west of the island vis (fig. 7). the embayment did not exist during most of the cretaceous in the area of the island of svetac, since the typical peritidal carbonates represented by the well-known shallow-water formations deposited on top of the acp (adcp cf. vlahović et al., 2005) are reported from the island (korbar et al., 2012; fig. 2). within the 3 m thick maastrichtian to palaeocene pelagic succession on the island of svetac (fig. 3) there are two types of intraclastic pelagic floatstones at the contact of the maastrichtian and palaeocene deposits (fig. 3). according to the abundance of pelagic mud and the pelagic intraclasts floating in a cohesive matrix, the floatstones are interpreted as muddy debrites (mulder & alexander, 2001). considering a deep-water depositional environment, the debrites have probably been deposited from debris flows within the basin or on the slope. the two debrites are amalgamated and it seems that the upper one eroded the lower one (fig. 3). thus, the k–pg transition is characterized by two amalgamated 0.5m thick debrites deposited at the top of maastrichtian and at the bottom of palaeocene, respectively. re-deposition and mixing of the maastrichtian and palaeocene pelagic mud intraclasts imply slope instability and a continuous basinal depositional environment during the maastrichtian to palaeocene in the area of the island of svetac. the lower (top maastrichtian) debrite is characterized by intraclasts (plasticlasts) of pelagic carbonates in a pelagic matrix that lack palaeocene planktonic foraminifera (fig. 3). the association of late maastrichtian planktonic foraminifera suggests mixing of a few biozones (fig. 5), while the latest one is referred to the abathomphalus mayaroensis zone. skeletons (bioclasts) of shallow-water benthic foraminifera and rudists are absent in the lower (maastrichtian) part of the section that points to re-deposition within the basin without the influence from the carbonate platform. it must be highlighted that the carbonate platform margins in the region were characterized by emergence and sediment starvation during the k–pg transition (mutti et al., 1996; vecsei & moussavian, 1997; bosellini et al., 1999). the figure 7. central-adriatic palaeogeography and depositional environments (grades of gray and italicised text) during the cretaceous–palaeogene (k–pg) transition. conservative reconstruction related to the recent arrangement of the central dalmatian islands (contoured by dotted lines). inferred transverse faults indicated by broken lines. g eologia c roatica korbar et al.: maastrichtian to palaeocene and eocene pelagic carbonates on the island of svetac (central adriatic, croatia) 103 emergence is also recognized on the acp southern margin (korbar, 2009), and the starvation could strongly influence the sedimentation rate within the supposed embayment (fig. 7). considering the unusual event beds reported from the islands of hvar (korbar et al., 2015) and brač (korbar et al., 2017a), both deposited within the peritidal domain of the acp at the k–pg boundary (fig. 7), the maastrichtian part of the complex debrite on the island of svetac could be tentatively interpreted as the k–pg event deposit. if so, it could be related to an extraordinary hydrodynamic event or an earthquake that was able to mobilize pelagic mud and semiconsolidated pelagic sediment from the deep embayment floor, and redeposit the mixture of mud and the intraclasts (plasticlasts) as a sedimentary load within the same pelagic depositional environment (fig. 7). the palaeocene debrite at the k–pg contact on the island of svetac contains both maastrichtian and palaeocene planktonic foraminifera in the matrix and maastrichtian pelagic intraclasts (fig. 3). the content of the debrite implies the existence of a slope along which re-deposition of unconsolidated and semi-consolidated pelagic mud occurred. the content thus implies mixing of fluidized maastrichtian pelagic mud and pelagic mudstone intraclasts, as well as palaeocene pelagic mud (cf. bice et al., 2007). considering the fact that the thin-sections of palaeocene (danian?) planktonic foraminifera cannot be determined to species level, the age of the upper debrite is related to the palaeocene p3 zone, defined according to the youngest association of planktonic foraminifera in the sample vss-4 (fig. 3). thus, the palaeocene debrite could be tentatively correlated to one of the palaeocene regional submarine landslides that are recorded within the pelagic succession of the neighbouring umbria-marche basin (montanari et al., 1989; bice et al., 2007). the maastrichtian to palaeocene was a period of intermittent collapses of the northern margin of the apulian carbonate platform into the adriatic basin (bosellini et al., 1999) and into the ionian counterpart on the southwest (rubert et al., 2012; fig. 1b). at least one of the regional danian events is also probably recorded within the danian peritidal succession on the neighbouring island of hvar (korbar et al., 2015). the benthic foraminifera in the separated eocene part of the presumably discontinuous pelagic succession on the island of svetac (fig. 3) imply a possible shallowing upward trend or a development of nearby neritic environments. in case of the later, it could also be interpreted as a skeletal muddy debrite. although the typical upper cretaceous lithostratigraphic unit of the gornji humac formation is characterized by peritidal limestones, the upper cretaceous carbonates referred to the formation on the basic geological map of the island of svetac (korbar et al., 2012) are characterized by highly diversified facies. besides, the carbonates are intensively tectonically fractured and recrystallized. therefore, it is not always possible to distinguish between typical peritidal and deeper-water facies (pelagic limestones with bioclastic intercalations, resembling allodapic limestones). however, the presented results suggest that during the maastrichtian the area of the island of svetac became a part of the adriatic basin, probably in the form of a deep embayment developed within the former platform domain (fig. 7). it is possible that the embayment has been opened along a transverse lineament that has been active during the various periods of the mesozoic, and could be related to the intermittent activity of the deep rooted fault zone striking sw-ne, along which the visšolta trough/graben formed during the triassic (grandić et al., 2002). presumably the deep-rooted fault also initiated development of a cenomanian-turonian intraplatform basin on the island of šolta that is characterized by the same strike (korbar et al., 2017b). the šolta intraplatform basin is situated along the northeastern continuation of the supposed transversal lineament (fig. 7). however, further investigations are necessary to test this hypothesis. nevertheless, the discovery of pelagic carbonates on the island of svetac is important for the reconstruction of the latest cretaceous to palaeogene palaeogeography of the central adriatic area. considering the hypothetical k–pg boundary tsunami that possibly originated in the atlantic ocean (korbar, 2019), the local palaeogeography could also be important for the reconstruction of the western tethys at the end of the mesozoic. 6. conclusions according to the micropaleontological and sedimentological analyses of the pelagic carbonates on the island of svetac it is possible to conclude the following: 1) the unusually thick-bedded to massive pelagic limestones on the island of svetac are rich in various species of planktonic foraminifera that imply a direct connection of the depositional environment with the open sea of the nearby adriatic basin. 2) the 3m thick succession is characterized by the assemblages of planktonic foraminifera that indicate the late maastrichtian abathomphalus mayaroensis zone and the upper part of the palaeocene p3 zone (morozovella angulata). 3) the transition from maastrichtian to palaeocene pelagic carbonates is not continuous but is characterized by amalgamated debrites that are related to at least two separated re-depositional events within the basin. 4) although the direct contact of palaeocene and eocene pelagic carbonates is not documented, the eocene pelagic facies, outcropping a few metres from the maastrichtian to palaeocene succession, implies a possible continuous maastrichtian to eocene pelagic environment on this part of the former adriatic carbonate platform. 5) it is possible to suppose that the maastrichtian opening of the deep-water pelagic environment of the adriatic basin within the former adriatic carbonate platform west of the island of vis could be related to a re-activation of an inherited transverse fault zone. acknowledgements this work was supported by the croatian ministry of science, education and sports through the scientific project “stratigraphy and geodynamic context of cretaceous deposits in the ne adriatic region” (181-1191152-2697) and “the basic gological map of the republic of croatia, scale 1:50000” (181-1811096-1093). we would like to thank to vlatko brčić for technical preparation of a composite photomicrograph. two anonymous reviewers are greatly acknowledged for their constuctive suggestions. we also wish to thank the editors for handling the manuscript until publication of the paper. references babić, lj, crnjaković, m. & asmerom, y. (2012): uplifted pleistocene marine sediments of the central adriatic island of brusnik.– geologia croatica, 65/2, 223–232. doi: 104154/gc.2012.13 belak, m., koch, g., grgasović, t., vlahović, i., velić, i., sokač, b. & benček, đ. (2005): novi prinos stratigrafiji evaporitno-karbonatno-klastičnovulkanogenog kompleksa komiškog zaljeva (otok vis, hrvatska) [new contribution to the stratigraphy of evaporitic-carbonate-clastic-volcanogenic complex of komiža bay (island of vis, croatia) – in croatian].– in. vlahović, i. & biondić, r. (eds.): 3. hrvatski geološki kongres (3rd croatian geological congress), opatija, abstract book, 13–14. g eo lo gi a c ro at ic a geologia croatica 73/2104 lučić, d., benić, j., stanković, d. & miletić, d. (1993): cretaceous/tertiary boundary from the koraljka-1 offshore well (sw of zadar, adriatic sea).– geologia croatica, 46, 41–61. montanari, a., chan, l.s. & alvarez, w. (1989): synsedimentary tectonics in the late cretaceous-early tertiary pelagic basin of the northern apennines.– in: crevello, p., wilson, j.l., sarg, r. & reed, f. (eds.): controls on carbonate platforms and basin development: sepm special publication, 44, 379–399. moro, a. & ćosović, v. (2013): upper turonian–santonian slope limestones of the islands of premuda, ist and silba (adriatic coast, croatia).– geologia croatica, 66/1, 1–13. doi: 10.4154/gc.2013.01 mulder, t. & alexander, j. (2001): the physical character of subaqueous sedimentary density flows and their deposits.– sedimentology, 48, 269–299. doi: 10.1046/j.1365-3091.2001.00360.x mutti, m., bernoulli, d., eberli, g.p. & vecsei, a. (1996): depositional geometries and facies associations in an upper cretaceous prograding carbonate platform margin (orfento supersequence, maiella, italy).– journal of sedimentary research, 66, 749–765. olsson, r.k., hemleben, c., berggren, w.a. & huber, b.t. (1999): atlas of paleocene planktonic foraminifera.– smithsonian contributions to paleobiology, 85, 252 p. doi: 10.5479/si.00810266.85.1 pamić, j., gušić, i. & jelaska, v. (1998): geodynamic evolution of central dinarides.– tectonophysics, 297, 273–307. pearson, p.n., olsson, r.k., huber, b.t., hemleben, c. & berggren, w.a. (2006): atlas of eocene planktonic foraminfera.– the cushman foundation for foraminiferal research, special publication, 41, 507 p. pikelj, k., juračić, m., hernitz-kučenjak, m. & aščić, š. (2015): surface sediment around the jabuka islet and the jabuka shoal: evidence of miocene tectonics in the central adriatic sea.– marine geology, 359, 120–133. doi: 10.1016/j. margeo.2014.11.003 premoli silva, i., rettori, r. & verga, d. (2003): practical manual of paleocene and eocene planktonic foraminifera.– department of earth sciences, university of perugia, italy, 152 p. premoli silva, i. & verga, d. (2004): practical manual of cretaceous planktonic foraminifera.– in: verga & rettori (eds.): international school on planktonic foraminifera, 3o course: cretaceous. universities of perugia and milan, tipografia pontefelcino, perugia (italy), 283 p. rosenbaum, g., lister, g.s. & duboz, c. (2004): the mesozoic and cenozoic motion of adria (central mediterranean): a review of constraints and limitations.– geodinamica acta, 17, 125–139. doi: 10.3166/ga.17.125-139 rubert, y., jati, m., loisy, c., cerepi, a., foto, g., & muska, k. (2012): sedimentology of resedimented carbonates: facies and geometrical characterisation of an upper cretaceous calciturbidite system in albania.– sedimentary geology, 257–260. 63–77, doi:10.1016/j.sedgeo.2012.02.009 sari, b. (2006): upper cretaceous planktonic foraminiferal biostratigraphy of the bey daglari autochton in the korkuteli area, western taurides, turkey.– journal of foraminiferal research, 36, 241–261. doi: 10.2113/gsjfr.36.3.241 sari, b. (2009): planktonic foraminiferal biostratigraphy of the coniacian-maastrichtian sequences of the bey daglari autochton, western taurides, turkey: thin-section zonation.– cretaceous research, 30, 1103–1132. doi: 10.1016/j.cretres.2009.03.007 schmid, s. m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski. k. (2008): the alpine-carpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss journal of geosciences, 101, 139–183. doi 10.1007/s00015008-1247-3 scisciani, v. & calamita, f. (2009): active intraplate deformation within adria: examples from the adriatic region.– tectonophysics, 476/1–2, 57–72. doi:10.1016/j.tecto.2008.10.030 sliter, w.v. (1989): biostratigraphic zonation for cretaceous planktonic foraminifers examined in thin section.– journal of foraminiferal research, 19, 1–19. doi: 10.2113/gsjfr.19.1.1 steuber, t., korbar, t., jelaska, v. & gušić, i. (2005): strontium-isotope stratigraphy of upper cretaceous platform carbonates of the island of brač (adriatic sea, croatia): implications for global correlation of platform evolution and biostratigraphy.– cretaceous research, 26, 741–756. doi:10.1016/j.cretres.2005.04.004 vecsei, a. & moussavian, e. (1997): paleocene reefs on the maiella platform margin, italy: an example of the effects of the cretaceous/tertiary boundary events on reefs and carbonate platforms.– facies, 36, 123–140. doi: 10.1007/bf02536880 vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: paleogeography, main events and depositional dynamics.– palaeogeography, palaeoclimatology, palaeoecology, 220, 333–360. doi:10.1016/j.palaeo.2005.01.011 wade, s.b., pearson, p.n., berggren, w.a. & pälike, h. (2011): review and revision of cenozoic tropical planktonic foraminiferal biostratigraphy and calibration to the geomagnetic polarity and astronomical time scale.– earth-science reviews, 104, 111–142. doi: 10.1016/j.earscirev.2010.09.003 young, j.r., wade, b.s. & huber, b.t. (2017, eds): pforams@mikrotax website.– 21 apr. 2017. url: http://www.mikrotax.org/pforams berggren, w.a. & pearson, p.n. (2005): a revised tropical to subtropical paleogene planktonic foraminiferal zonation.– journal of foraminiferal research, 35, 279–298. bice, d.m., montanari, a. & rusciadelli, g. (2007): earthquake-induced turbidites triggered by sea level oscillations in the upper cretaceous and paleocene of italy.– terra nova, 19, 387–392. doi: 10.1111/j.1365-3121.2007.00752.x bosellini, a., morsilli, m. & neri, c. (1999): long-term event stratigraphy of the apulia platform margin (upper jurassic to eocene, gargano, southern italy).– journal of sedimentary research, 69, 1241–1252. doi: 10.2110/jsr.69.1241 channell, j.e.t., d’argenio, b. & horvath, f. (1979): adria, the african promontory, in mesozoic mediterranean palaeogeography.– earth-science review, 15, 213–292. doi: 10.1016/0012-8252(79)90083-7 cvetko tešović, b., gušić, i., jelaska, v. & bucković, d. (2001): stratigraphy and microfacies of the upper cretaceous pučišća formation, island of brač, croatia.– cretaceous research, 22, 591–613. doi: 10.1006/cres.2001.0279 d’argenio, b., radoičić, r. & sgrosso, i. (1971): a paleogeographic section through the italo-dinaric external zones during jurassic and cretaceous times.– nafta, 22/4–5, 195–207. eberli, g.p., bernoulli, d., sanders, d. & vecsei, a. (1993): from aggradation to progradation: the maiella platform (abruzzi, italy).– in: simo, a.j., scott, r.w. & masse, j.-p. (eds): cretaceous carbonate platforms, memoirs of american association of petroleum geology, 56, 213–232. flügel, e. (2010): microfacies of carbonate rocks.– heidelberg, springer, 984 p. doi: 10.1007/978-3-642-03796-2 fuček, l., jelaska, v., gušić, i., prtoljan, b. & oštrić, n. (1991): padinski turonski sedimenti uvale brbišnica na dugom otoku [turonian slope deposits in the brbišnica cove, dugi otok island, croatia – in croatian].– geološki vjesnik, 44, 55–67, zagreb. geletti, r., del ben, a., busetti, m., ramella., r. & volpi, v. (2008): gas seeps linked to salt structures in the central adriatic sea.– basin research, 20, 473–487. doi: 10.1111/j.1365-2117.2008.00373.x. grandić, s., boromisa-balaš, e., šušterčić, m. & kolbah, s. (1999): hydrocarbon possibilities in the eastern adriatic slope zone of croatian offshore area. – nafta, 50/2, 51–73. grandić, s., biancone, m. & samaržija, j. (2002): geophysical and stratigraphic evidence of the adriatic triassic rift structures.– mem. soc. geol. it., 57, 315–325. gušić, i. & jelaska, v. (1990): stratigrafija gornjokrednih naslaga otoka brača u okviru geodinamske evolucije jadranske karbonatne platforme [upper cretaceous stratigraphy of the island of brač within the geodynamic evolution of the adriatic carbonate platform – in croatian].– djela jugoslavenske akademije znanosti i umjetnosti, 69, institut za geološka istraživanja, oour za geologiju, 160 p., zagreb. husinec, a. (2002): stratigrafija mezozojskih naslaga otoka mljeta u okviru geodinamske evolucije južnoga dijela jadranske karbonatne platforme.– unpublished phd thesis, zagreb university, 300 p. (includes english summary). korbar, t. (2009): orogenic evolution of the external dinarides in the ne adriatic region: a model constrained by tectonostratigraphy of upper cretaceous to paleogene carbonates.– earth-science reviews, 96, 296–312. doi: 10.1130/2019.2542(16). korbar, t. (2019): the cretaceous-paleogene boundary tsunamite on the adriatic carbonate platform and possible source of a hypothetical atlantic-to-western-tethys megatsunami.– in: koeberl, c. & bice, d. (eds): 250 million years of earth history in central italy: celebrating 25 years of the geological observatory of coldigioco, geological society of america special papers, 542. 319–332. doi: 10.1130/b31084.1 korbar, t., cvetko tešović, b., radovanović, i., krizmanić, k., steuber, t. & skelton, p.w. (2010): campanian pseudosabinia limestones from the pučišća formation on the island of hvar (adriatic sea, croatia).– turkish journal of earth sciences, 19/6, 721–731. doi:10.1016/j.cretres.2005.04.004 korbar, t., belak, m., fuček, l., husinec, a., oštrić, n., palenik, d. & vlahović, i. (2012): osnovna geološka karta republike hrvatske m 1:50 000, vis 3 i biševo 1 (571/3 i 621/1) [basic geological map of the republic of croatia 1:50000, sheet vis 3 and biševo 1 – in croatian].– hrvatski geološki institut, zavod za geologiju, zagreb. isbn: 978-953-6907-27-4. http://www.hgi-cgs.hr/ ogk50/vis.html korbar, t., montanari, a., premec-fućek, v, fuček, l., coccioni, r., mcdonald, i., claeys, p., schulz, t. & koeberl, c. (2015): cretaceous-paleogene boundary tsunami deposit in the intra-tethyan adriatic carbonate platform section of hvar (croatia).– geological society of america bulletin, 127, 1666–1680. doi: 10.1130/b31084.1 korbar, t., mcdonald, i., premec fućek, v., fuček, l. & posilović, h. (2017a): post-impact event bed (tsunamite) at the cretaceous–palaeogene boundary deposited on a distal carbonate platform interior.– terra nova, 29, 135–143. doi: 10.1111/ter.12257 korbar, t., fuček, l., brčić, v. & palenik, d. (2017b): osnovna geološka karta republike hrvatske m 1:50 000, list “šolta, čiovo, drvenik” [basic geological map of the republic of croatia, sheet „šolta, čiovo, drvenik“ – in croatian].– hrvatski geološki institut, zavod za geologiju, zagreb. isbn: 978-9536907-59-5. http://www.mikrotax.org/pforams http://www.hgi-cgs.hr/ogk50/vis.html http://www.hgi-cgs.hr/ogk50/vis.html g eologia c roatica korbar et al.: maastrichtian to palaeocene and eocene pelagic carbonates on the island of svetac (central adriatic, croatia) 105 appendix list of maastrichtian, palaeocene and eocene taxa cited in the text and figure captions (in alphabetical order according to genus): maastrichtian planktonic foraminifera abathomphalus mayaroensis (bolli, 1951) contusotruncana contusa (cushman, 1926) contusotruncana fornicata (plummer, 1931) contusotruncana patelliformis (gandolfi, 1955) globotruncana arca (cushman, 1926) globotruncana cf. orientalis el-naggar, 1966 globotruncanella havanensis (voorwijk, 1937) globotruncanella cf. petaloidea (gandolfi, 1955) globotruncanella pschadae (keller, 1946) globotruncanita conica (white, 1928) globotruncanita insignis (gandolfi, 1955) globotruncanita stuarti (de lapparent, 1918) gublerina sp. heterohelix sp. kuglerina rotundata (broennimann, 1952) macroglobigerinelloides sp. muricohedbergella sp. pithonella innominata (bonet, 1956) pithonella ovalis (kaufmann, 1865) pithonella sphaerica (kaufmann, 1865) planoglobulina acervulinoides (eger, 1899) racemiguembelina fructicosa (egger, 1899) ventilabrella sp. palaeocene planktonic foraminifera globanomalina chapmani (parr, 1938) globanomalina ehrenbergi (bolli, 1957) igorina pusilla (bolli, 1957) igorina tadjikistanensis (bykova, 1953) morozovella angulata (white, 1928) parasubbotina pseudobulloides (bolli, 1957) subbotina cancellata blow, 1979 subbotina triangularis (white, 1928) subbotina triloculinoides (plummer, 1926) subbotina velascoensis (cushman, 1925) eocene planktonic foraminifera acarinina bullbrooki (bolli, 1957) acarinina mcgowrani wade & pearson, 2006 globigerinatheka kugleri (bolli, loeblich & tappan, 1957) morozovelloides crassatus (cushman, 1925) pseudoglobigerinella bolivariana (petters, 1954) subbotina eocaena (guembel, 1868) subbotina yeguaensis (weinzierl & applin, 1929) turborotalia frontosa (subbotina, 1953) g eo lo gi a c ro at ic a geologia croatica 73/2106 figure 2/supplement. outcrops of massive maastrichtian pelagic carbonates on the eastern coast of the island of svetac partly covered by colluvial carbonate breccia (p) deposited along a generally east-west striking sveti andrija fault (fig. 2). outcrops of lower cretaceous carbonates are visible in the background. figure 3/supplement. the main sampling points within the thick-bedded to massive pelagic carbonates on the eastern part of the island of svetac along the walking trail at smokvica. note the heavily vegetated area around the section. 2020 | 73/1 | 29–48 | 14 figs. | 12 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction there are several bentonite deposits and occurrences in croatia and neighbouring countries formed by alteration of volcanic ash, in different geological settings with ages ranging from the late jurassic to the middle miocene. some of these deposits were exploited in the past, and with technological advancements and new applications emerging, some of them could be economically viable again. bentonite is used for numerous purposes, most commonly in drilling fluids, metal castings, civil-engineering, as pet-waste adsorbents, desic­ cants, environmental sealants etc. other uses of bentonite, includ­ ing the pharmaceutical and cosmetic industries, nanotechnology and various other uses, such as barrier materials for storing nu­ clear waste or removing contaminants from wastewater, are gain­ ing momentum. such diversity and abundance of possible appli­ cations calls for a thorough understanding of bentonite, including its different types and properties. properties of different bentonites vary widely because of the variations in their mineralogical composition. the smectite spe­ cies is the most important factor determining bentonite proper­ ties, such as adsorption capacity or swelling behaviour. as the main constituent and the one giving bentonite its specific char­ acteristics, smectite is the obvious object of interest in most of the research done on bentonites. different types of smectites were distinguished by grim & kulbicki (1961), schultz (1969), brigatti & poppi (1981), and brigatti (1983). they proposed trivial names, de­ rived from the provenance of the most typical samples, such as wyoming, tatatilla, chambers, and otay (cheto), which differ in comprehensive characterisation of bentonites from croatia and neighbouring countries zvonka gverić1, darko hanžel2, štefica kampić1, andrej pleša3 and darko tibljaš*,1 1 university of zagreb, faculty of science, department of geology, division of mineralogy and petrology, horvatovac 95, hr-10 000, zagreb, croatia; (*corresponding author: dtibljas@geol.pmf.hr) 2 jožef stefan institute, jamova cesta 39, si-1000 ljubljana, slovenia 3 ina d.d., exploration and production, avenija većeslava holjevca 10, hr-10 000, zagreb, croatia doi: 10.4154/gc.2020.02 abstract bentonites are an important industrial resource and are also interesting from the mineralogical point of view. the main component of bentonites is a mineral from the smectite group in which chemical and structural variations, influencing bentonite properties, provide a great deal of interesting research topics. the aim of this study was to better describe bentonites from 11 known deposits from croatia and neighbouring countries: bednja, bunarić, draga, divoselo, sjeničak, paripovac, lončarski vis and poljanska luka (croatia), zaloška gorica (slovenia), šipovo (bosnia and herzegovina) and vranjska banja (serbia). thirteen samples were analysed using several available techniques in order to obtain the data necessary for currently accepted bentonite classification. the mineralogical composition was analysed using xrd and ftir, and crystallochemical properties were investigated by thermal analysis, cec determination with ammonium index cations, chemical analyses (icp-aes and icp-ms) and mössbauer spectroscopy. the results showed that the main mineral constituent of most local bentonite deposits is a fe-poor smectite, with a predominantly medium layer charge mostly as a result of octahedral substitutions, with calcium or sodium cations occupying the interlayer. nevertheless, the variations between samples are prominent enough to provide a good overview of the range of crystallo-chemical properties which exist in different smectites resulting in varying bentonite properties. layer charge (particularly in its value and whether it originates from substitutions in the tetrahedral or octahedral sheets), hightemperature transformations, and fe content. unfortunately, these trivial names do not reflect some of the important chemical and structural parameters. furthermore, several montmorillo­ nites could not be assigned to the proposed types according to this classification system. therefore emmerich et al. (2009) proposed a new comprehensive classification, which allowed modifications and extension of the old one. it is based on the chemical composition (tetrahedral/octahedral charge distribu­ tion), the layer charge and exchangeable cations, the diand trioctahedral character, fe content and the structure of the octa­ hedral sheet (cis­, trans-vacancy). the new classification (which is also used here) is based on standardised laboratory techniques used in characterisation of smectites. the most extensive research on bentonites in croatia was done by braun (1991) and it has served as a foundation for many later works. some of the other research was undertaken for industrial purposes, which goes along with the fact that 9 samples (from 7 locations) used in this study were taken from active or once active bentonite mines where bentonite was used in drilling fluids and castings. the data gathered from this industrial-based research has been compiled by marković (2002). additionally, bentonite deposits in the north­eastern part of croatia have been studied by tibljaš (1996), and those in south croatia by šegvić et al. (2006) and biševac et al. (2007). samples of bentonite contain different smectite, resulting in their varying properties. considering the large array of possibili­ ties for bentonite use, it is important to be able to choose the article history: manuscript received september 25, 2019 revised manuscript accepted january 17, 2020 available online february 29, 2020 keywords: bentonite deposits, smectite crystallo-chemical properties g eo lo gi a c ro at ic a geologia croatica 73/130 sample with desirable properties appropriate for the specific ap­ plication. consequently, an accurate identification and classifica­ tion of the different smectites is important and the aim of this study was to reinvestigate croatian bentonites by several available techniques and methods, and classify them in accordance with the criteria from contemporary literature. for comparison, a few samples of bentonites of similar ages from neighbouring countries were also studied. 2. geological setting the investigated bentonites differ in age and depositional envi­ ronments (fig. 1, table 1) whereby the oldest, bunarić (from the maovice-štikovo area), located in the external dinarides, was deposited in late jurassic (malmian-kimmeridgian) lemeš beds. the sedimentary succession, consisting of light­coloured platy limestone and/or dolomitic limestone and dolomite with chert intercalations, formed on the adriatic carbonate platform in an intraplatform trough, connected to the open tethyan realm (vlahović et al., 2005). two bentonite layers exist within the succession, separated by 4 to 6 m of limestone and chert. the lower layer is approx. 3.5 m thick while the thickness of the up­ per layer varies between 1.5 and 5.5 m (braun, 1991). bentonites from zaloška gorica and bednja were deposited during the oligocene and the early miocene (eggenburgian), re­ spectively, in the slovenia-zagorje basin (szb). the szb is also known as the trans-tethyan trench corridor which acted as a marine connection between the paratethys and the mediterranean (rögl, 1998). this region formed prior to the southern panno­ nian basin (spb) installation at the south-eastern margin of the paratethys basin (mandic et al., 2012). the zaloška gorica deposit is located in the northern part of the celje basin within a bentonite belt extending for 15 km. the bentonite occurs in three exploitable layers in the upper part of an andesitic tuff horizon which is up to 100 m thick and is intercalated with the oligocene clays overlying triassic rocks. these clays are conformably overlain by the badenian lithothamnium sandstones and conglomerates and quartz sands as the youngest miocene sediments (rihteršič, 1958; držaj & lukacs, 1968). in the bednja area (known for its bentonite deposits), the šaša clay pit is the largest. the irregular plate-shaped bentonite body which occurs there is 10 to 35 m thick and 165 m wide, tec­ tonically embedded within coarse-grained marine arenites. the body is composed of a random mixture of different varieties of altered pyroclastic rocks: volcanic agglomerates, lapilli tuff, banded and pelitic tuff (braun, 1991). based on the fossil con­ tent and superposition, the sediments were deposited during the late eggenburgian-early ottnangian and belong to the vrbno member of the macelj formation (avanić, 2012). another group of deposits was formed in the spb, prior to paratethys flooding, in lakes closely related to the dinaride lake system (dls) (mandic et al., 2012 and references therein). in the area around gornja jelenska, bentonite clays, formed by the alteration of andesitic vitroclastic tuff, were discovered in several deposits. a sample from the draga deposit was used in this study. according to braun (1991), three bentonite layers (0.15-0.9 m, 0.2-1.2 m and 0-2.0 m thick) occur in continental, most probably lacustrine ottnangian, strongly tectonized sediments, repre­ sented by gravel, sand, silt, sandy and tuffitic marl, tuffite and sandy clay which alternate both vertically and laterally. all three bentonite layers have a sharp contact with the underlying layer, while they gradually transit to tuffite in the overlying layer. based on palynological analyses, krizmanić (1995) con­ cluded that the bentonite was deposited during the late karpatian to the early badenian in a swamp with gently inclined shores, but with deeper water areas. in the area around šipovo (bosnia and herzegovina), several bentonite deposits (vujnović, 1981) formed in the intra-mon­ taine basin of the dls (krstić et al., 2001). in the grabež and sarići deposits, three bentonite layers are underlain by lower miocene sandy clay. the bentonite layers (approximately 2.5, 2 and 5.5 m thick) are separated by 1 5 m of clastic rocks. to the south, in the babići and greda deposits, two bentonite layers were de­ scribed by miladinović (1976) and vujnović (1981). there are some controversies concerning their age. according to litera­ ture, they were deposited in the middle miocene (miladinović, 1976), middle to late miocene (vujnović, 1981) or even the late miocene (trubelja & barić, 1979), but the newest palaeontological data (krstić et al., 2001 and references therein) figure 1. sampling locations (abbreviations defined in table 1), a = austria; bih = bosnia and herzegovina; h = hungary; hr = croatia, i = italy; mne = montenegro; rks = kosovo; slo = slovenia; srb = serbia. table 1. list of samples. sample sampling location age bu bunarić, central dalmatia, s croatia late jurassic (kimmeridgian) (braun, 1991) zg* zaloška gorica, e slovenia oligocene (rihteršič, 1958) bd bednja, hrvatsko zagorje, nw croatia early miocene (eggenburgianottnangian) (braun, 1991) dr draga, moslavina, central croatia early miocene (ottnangian) (braun, 1991) ši1 sokolac, šipovo, central bosnia and herzegovina early miocene (krstić et al., 2001) ši2 greda, šipovo, central bosnia and herzegovina early miocene (krstić et al., 2001) sj sjeničak, central croatia middle miocene (badenian) (mandic et al., 2012) pr paripovac, central croatia middle miocene (badenian) (mandic et al., 2012) di1 divoselo, lika, sw croatia unknown di2 divoselo, lika, sw croatia unknown lv lončarski vis, slavonija, e croatia early miocene (karpatian) (marković et al., 2018) vb* vranjska banja, se serbia early to middle miocene (krstić et al., 2001) pl poljanska luka, hrvatsko zagorje, nw croatia middle miocene (badenian) (braun, 1991) *samples from the collection of the division of mineralogy and petrology, faculty of science. g eologia c roatica gverić et al.: comprehensive characterisation of bentonites from croatia and neighbouring countries 31 show that the lacustrine sediments were deposited in the middle early miocene, i.e. between 19 and 17 ma ago. other lacustrine deposits are observable at sjeničak and paripovac (30 km apart), in the karlovac and glina sub-depressions where a 0.5 m thick altered volcanic ash occurs in the upper part of the sediments deposited in the early badenian (≈16.0 ma, based on 40ar/39ar dating). in sjeničak, the bentonite is represented by a biotite­bearing montmorillonite clay layer, underlain by more than 6 m of interbedded sands, pelites and limestone, and is posi­ tioned 2 m below the transgression horizon, marked by a marine organogenic limestone of badenian age. in paripovac, the ash is grey, medium-size sand, with white calcite veins and biotite flakes. it is intercalated in a sedimentary sequence consisting of 2 m of clays and silts below the ash and about 1 m of clays and lacustrine limestone above the ash deposit (mandic et al., 2012). bentonite from divoselo most probably also belongs to this group of deposits, based on the similarity of the tuff mineral as­ sociations and mineral morphology with those from neogene ba­ sins in dalmatia, although its age and depositional environment is unknown. clays were discovered under a thin quaternary cover on the palaeorelief formed on malmian carbonates. in the boreholes, usually one to three bentonite layers occur in the first 10 m (0.3-0.5, 1.6-2.0 and approx. 2 m thick). these are separated by tuff layers, though sometimes due to erosion the first one or two layers are missing. in one of the deeper boreholes, a 13.2 m thick clay layer was observed, and in another, bentonite clay was observed at a depth of 24.3 m (marković, 2002). in the spb, bentonites were also formed in marine environ­ ments. in lončarski vis, (an area close to gradac village), there are several quartz-trachyandesite quarries. apart from the main volcanic body, smaller flows and tuff layers are interstratified within karpatian marine sediments (breccia-conglomerates, gravels, sands and marls) (pamić, 1997 and references therein). some tuff layers are altered to bentonite. radiometric dating us­ ing 40ar/39ar dated tuffs at 16.96 ± 0.03 ma, corresponding to karpatian age (marković et al., 2018). the poljanska luka bentonite deposit, also formed in the spb after the paratethys flooding, and contains four beds of ben­ tonite clay as a result of the alteration of vitroclastic tuff. two lower layers, between 0.6 and 1 m thick, extend over 1800 m and were previously exploited. they are bound on the upper and lower surfaces by 0.5 m thick layers of altered tuffite. bentonites are interstratified in badenian marls, calcilutites and biomicrites, which were deposited in a lagoon environment (braun, 1991; marković, 2002). the bentonite sample from vranjska banja (serbia) was taken from the collection of the division of mineralogy and pe­ trology at the faculty of science, university of zagreb, so its ex­ act geographic and stratigraphic positions are unknown. it origi­ nates from the area in which pyroclastic material is widespread and is better known for zeolite than bentonite deposits (simić, 2001; simić et al. 2014). according to krstić et al. (2001) a large outcrop from vranje to vranjska banja with prevailing tuff layers and subordinate tuffaceous sandstones and breccias, and an andesite lava flow, formed in a fresh water lacustrine environ­ ment (serbian lake) during the transition from the lower into the middle miocene. according to the older sources (vukanović et al., 1977) this outcrop belongs to the upper eocene sedimentary succession within the pčinja palaeogene ba­ sin comprising up to 750 m of pyroclastic rocks. the pyroclastics were deposited on land and in shallow fresh water (lacustrine, braided river) environments which prograded into a marine one. 3. materials and methods the bentonite samples used in this study, named after the loca­ tions where they were collected from are: bednja, poljanska luka, draga, lončarski vis, paripovac, sjeničak, bunarić, two samples from divoselo (croatia); two samples from šipovo (bosnia and herzegovina); vranjska banja (serbia) and zaloška gorica (slovenia) (fig. 1, table 1). preparation of the samples included either grinding in an aga te mortar to prepare whole rock (wr) samples or separation of the clay-size (< 2 µm) fraction by centrifugation. approximately 50 g of sample was dispersed in approximately 600 ml of dis­ tilled water, then the resulting slurry was centrifuged using a teht­ nica centric 322a machine, configuration time calculated using centrifuge software (krumm, 1994). the suspended clay-size particles were taken from the top of the suspension. wr samples were used to determine the mineral composition (xrd), cation exchange capacity (cec) and chemical composition, while the clay-size fraction was used for clay mineral determination (xrd), ftir analysis, chemical analysis, determination of the structural iron characteristics and thermal properties. 3.1. x-ray diffraction (xrd) xrd analyses were performed on both wr and clay-size frac­ tion samples using a philips pw3040/60 x’pert pro diffractometer equipped with cu tube (40 kv and 40 ma), graphite mono­ chromator and proportional counter. the following slits were used: mask 10 mm, 1/2° divergence slit, 1° and 2° antiscatter slits on tube and detector side respectively, and a 0.2 mm receiving slit. the samples were scanned in continuous mode at a speed of 0.02 °2θ/s. diffraction patterns were processed using an x’pert highscore computer program (pananalytical, 2004) and com­ pared with the powder diffraction file database and with the data from literature (brown, 1961; brindley & brown, 1980; moore & reynolds, 1997). the clay-size fraction (< 2 μm) was analysed as a randomly oriented powder and was also used to make oriented mounts on glass slides (after moore & reyn­ olds, 1997). oriented samples were analysed as air-dried, after leaving the glass slides overnight in ethylene glycol vapour, and after heating for 1 h at 400 °c and 550 °c. clay minerals were identified by observing changes on diffractograms after different treatments using the flowchart from starkey et al. (1984). to differentiate between smectites and vermiculites, mont­ morillonite and beidellite, and to estimate the layer charge, clay­ size fractions were treated with magnesium, lithium and potas­ sium chloride solutions (concentrations: 3m for lithium chloride and 1m for magnesium and potassium chloride solutions). ap­ proximately 200 mg of the sample (<2 µm fraction) was mixed with 30 ml of solution (done separately for each chloride solution) in cuvettes and left overnight on a shaker at 250 rpm. the suspen­ sion was then centrifuged at 3500 rpm for 15 minutes, the super­ natant then decanted and the sample washed three times with ethanol solution (80%). materials saturated with a cation of interest were dispersed in a few drops of distilled water and analysed as oriented glass slide mounts using xrd. magnesium saturated samples were solvated with glycerol following the procedure pro­ posed by środoń (1980), i.e. left overnight covered with glycerol-soaked filter paper. lithium saturated samples were heated to 200 °c and treated with glycerol (again covered overnight with glycerol-soaked filter paper) following greene-kelly (1955). the approximate layer charge was inferred using part of the method described by christidis & eberl (2003). the swell­ ing behaviour of potassium saturated samples, which were fully expandable in the original form was observed, adopting the prin­ g eo lo gi a c ro at ic a geologia croatica 73/132 ciple that low-charge smectites would swell to >16.6 å after 12+ hours in a desiccator with ethylene-glycol vapours, while the highcharged ones would show a basal peak between 13.5 and 15.5 å. a randomly oriented clay-size powder was additionally ana­ lysed in step-scan mode (step 0.02 °2θ, time 5 s) in the range from 58.5 to 64.5 °2θ to measure 060 peak positions and determine the b cell dimension (by multiplying d060 by 6). quartz was used as an external standard. 3.2. fourier transform infrared (ftir) spectroscopy approximately 2 mg of the clay size fraction was mixed with ap­ proximately 200 mg of kbr powder, homogenized and pressed into pellets with a diameter of 13 mm. the spectra were recorded immediately after pressing, after which the pellets were heated at 150 °c overnight and cooled down in a desiccator before repeated recording. the spectra were obtained using a bruker tensor 27 ftir spectrometer equipped with a kbr beam splitter. thirty-two scans in the mir (4000 – 400 cm-1) region were recorded for each sample with a resolution of 2 cm-1. the spectra were interpreted using data from the literature (madejová & komadel, 2001; russell & fraser, 1994). 3.3. cec determination nh4 + ions were used as index cations to determine the cation ex­ change capacity following the procedure proposed by minato (1997) for zeolites. homogenized portions of the wr sample (1 g) were dried and suspended in 30 ml 1m ammonium acetate so­ lution. after mixing, the suspension was centrifuged at 3500 rpm for 17 minutes and the precipitate was washed three times with ethanol. nh4 + cations were then exchanged with potassium cations using 30 ml 1m potassium chloride solution, centrifuged at 3500 rpm for 8 minutes and the supernatant was preserved. this was repeated three times for each sample. the released ammo­ nium cations were measured using a hach ammonium probe. 3.4. thermal analyses six samples (bd, bu, di1, dr, pl and ši1) of about 20 mg were analysed using a shimadzu tg/dta instrument. the heating rate was 20 k/min in the 30 – 1000 °c range. the analysis was performed in an air current (flow rate: 100 ml/min), samples were placed in platinum crucibles and an empty crucible was used as a reference material. the instrument was calibrated using in­ dium, tin and aluminium for temperature and dta correction. the remaining 7 samples were analysed using a mettler to­ ledo tg/sdta 851e. the heating rate was 10 k/min in the 30 – 1000 °c range. samples (around 35 mg of each) were analysed in aluminium oxide crucibles in an oxygen atmosphere (flow rate: 150 ml/min) while nitrogen was used as a protective gas (50 ml/ min). an empty crucible was used as a reference material. dehydration and dehydroxylation temperatures were read by observing the peak positions on dta/dtg curves, no peak de­ composition was made. 3.5. chemical analysis major and trace elements both in the wr and clay-size fraction of the samples were analysed using icp-aes (spectro ciros vi­ sion instrument) and icp-ms (elan 9000 instrument) in the bu­ reau veritas mineral laboratories (vancouver, canada). the sample weight used was 0.2 g for each analysis. for major and some trace element analysis samples were fused with lithium metaborate and tetraborate and dissolved in diluted nitric acid. other trace elements (au, ag, as, bi, cd, cu, hg, mo, ni, pb, sb, se, tl and zn) were analysed using icp-ms after the samples were dissolved in aqua regia. carbon and sulfur were analysed on leco induction furnace cs230 and loi was determined after burning the sample at 1000 °c. the chemical composition of the <2 µm fraction was used to calculate the chemical formulae of the samples. considering the impurities found in this fraction (both by xrd and ftir methods), corrections for the crystalline impurities were made. their quantities were assumed based on xrd peak intensities and for some samples a trial­and­error type deduction, necessary to obtain reasonable formulae (e.g. si<4, sum of octahedral cations = 2, charge balance of the layer and interlayer cations) was undertaken. mostly, the impurities were present only in relatively small amounts. the corrected chemical composition was then used to calcu­ late the structural formula based on half a unit cell with o10oh2 and 22 negative charges and calculated after stevens (1946). cations were appointed to different positions as follows: – all si atoms were assigned to the tetrahedral sheet – the rest of the spaces in the tetrahedral sheet were given to al or al and fe3+ where mössbauer spectroscopy showed tetrahedrally coordinated fe3+ – the remaining al and fe3+ together with fe2+ were assigned to the octahedral sheet table 2. mineral compositions of the samples (wr and <2 µm fractions) determined by xrd. sample smectite kaolinite illite plagioclase quartz opal-ct calcite zeolite volcanic glass bu + x + + + x + zg + x + x + + + x bd + x + x + + + + x + dr + x + x + + x ši1 + x + x + x + ši2 + x + x + x + sj + x + x + pr + x + x + + di1 + x + x + di2 + x + x + + + x lv + x + vb + x + + + x + pl + x + + + x + present in the wr sample x present in the < 2 µm fraction g eologia c roatica gverić et al.: comprehensive characterisation of bentonites from croatia and neighbouring countries 33 – the unoccupied spaces in the octahedral sheet were filled by mg – na, ca, k and leftover mg were assigned to the interlayer. 3.6. mössbauer spectroscopy fe distribution among the tetrahedral and octahedral sheets and its valence state was analysed using mössbauer spectroscopy. mössbauer spectra were recorded at room temperature using a constant acceleration wissel spectrometer, in transmission mode with co-57 source in rh matrix. velocity calibration was per­ formed using a thin α-fe foil. the isomer shifts are expressed relative to α-fe at room temperature. the spectra were fitted with the analysis code recoil (lagarec & rancourt, 1998) using quadrupole doublets of lorentzian lineshape. 4. results 4.1. x-ray diffraction (xrd) randomly oriented powder mounts of wr samples revealed that, apart from clay minerals, the samples contain variable amounts of other minerals: quartz, opal-ct, calcite, plagioclase feldspars figure 2. xrd patterns of bu <2 µm fraction, oriented samples, (a) air dried, (b) glycolated, (c) heated to 400 °c, (d) heated to 550 °c, cuka radiation. figure 3. xrd patterns of di1 sample (<2 µm) after greene-kelly test, lithium saturated sample heated at 200 °c (grey); after glycerol treatment (black), cuka radiation. g eo lo gi a c ro at ic a geologia croatica 73/134 ta bl e 3. d -v al ue s [ å ] o f 0 0l a nd 0 60 p ea ks m ea su re d on o rie nt ed sa m pl e (e xc ep t f or 0 60 ) o f d iff er en tly tr ea te d <2 μ m fr ac tio n, a nd c v va lu es fo r e g tr ea te d ksa tu ra te d sa m pl es . bu zg bd a d eg 55 0 °c li -2 00 -g ly m gg ly keg a d eg 55 0 °c li -2 00 -g ly m gg ly keg a d eg 55 0 °c li -2 00 -g ly m gg ly keg 00 1 14 .5 0 16 .7 8 9. 80 9. 70 18 .0 7 14 .1 2 14 .5 6 17 .3 8 9. 69 (b ) 9. 41 18 .0 6 16 .3 6 10 .6 6 17 .1 5 9. 85 9. 60 18 .0 9 15 .7 0 00 2 8. 54 6 4. 81 2 4. 75 6 9. 06 8. 28 6 8. 35 7 8. 86 (b ) 4. 86 8 8. 72 4. 82 2 4. 71 73 9. 03 00 3 4. 94 7 5. 52 8 3. 20 12 5. 91 9 4. 62 9 5. 67 3 5. 97 5 5. 56 (b ) 3. 19 57 5. 60 3. 20 (b , a ) 00 4 4. 48 4 3. 39 74 4. 43 4. 32 00 5 2. 99 31 3. 34 06 1. 92 93 3. 55 28 3. 42 82 3. 46 1 1. 93 92 3. 37 1. 93 31 3. 39 51 00 6 2. 78 00 2. 99 00 2. 84 28 2. 82 9 (b ) 2. 82 2. 82 57 cv 2. 72 2. 96 4. 40 06 0* 1. 49 83 1. 49 52 1. 50 23 d r ši 1 ši 2 a d eg 55 0 °c li -2 00 -g ly m gg ly keg a d eg 55 0 °c li -2 00 -g ly m gg ly keg a d eg 55 0 °c li -2 00 -g ly m gg ly keg 00 1 12 .4 9 17 .2 0 9. 84 9. 71 18 .1 0 16 .4 0 14 .3 2 17 .3 2 10 .1 1 17 .6 0 18 .4 7 14 .2 3 15 .0 9 17 .1 5 9. 67 9. 65 18 .1 6 15 .7 7 00 2 4. 93 4 8. 58 6 4. 81 4 4. 74 5 9. 08 (b ) 8. 93 (b ) 8. 44 3 4. 88 9 9. 13 9. 14 8. 51 8 4. 74 4 4. 77 4 9. 02 3 00 3 5. 62 0 3. 15 04 5. 95 (b ) 5. 59 (b ) 4. 90 3 5. 61 1 5. 84 7 5. 88 8 4, 67 (b ) 4. 98 5. 62 3 5. 94 7 00 4 3. 11 50 4. 27 8 3. 56 5 4. 23 3 4. 55 1 4. 43 9 3. 42 6 00 5 3. 36 29 1. 93 02 3. 41 7 2. 99 3 3. 36 44 3. 50 88 3. 58 8 2. 77 9 (b ) 3. 00 3. 37 02 3. 41 80 00 6 2. 83 11 2. 79 05 3. 02 95 3. 00 2 2. 81 62 2. 82 4 (b ) cv 3. 62 1. 54 5. 69 06 0* 1. 49 91 1. 49 83 1. 49 68 sj pr d i1 a d eg 55 0 °c li -2 00 -g ly m gg ly keg a d eg 55 0 °c li -2 00 -g ly m gg ly keg a d eg 55 0 °c li -2 00 -g ly m gg ly keg 00 1 14 .8 8 17 .2 8 9. 59 18 .8 14 .0 7 (1 7. 56 ) 16 .7 4 14 .6 1 17 .1 5 9. 91 9. 68 17 .8 4 (1 4. 24 ) 17 .2 6 13 .6 1 17 .0 3 9. 70 17 .9 2 18 .2 5 16 .6 8 00 2 7. 19 5 8. 53 3 4. 74 9 9. 56 7. 13 (b ) 8. 68 6 8. 53 3 4. 81 9 4. 74 4 8. 92 1 8. 65 9 7. 41 0 8. 47 0 4. 78 9. 11 9 8. 89 3 00 3 5. 00 8 5. 65 7 4. 73 5 5. 71 2 4. 94 4 5. 66 1 5. 92 9 5. 73 8 5. 62 0 5. 93 8 5. 62 3 00 4 3. 59 03 4. 24 7 4. 70 2 4. 35 0 4. 25 75 4. 74 9 4. 32 35 3. 62 1 4. 50 02 00 5 3. 03 00 3. 39 43 3. 42 51 3. 02 74 3. 39 61 3. 43 87 3. 15 18 3. 36 93 3. 55 56 3. 42 48 00 6 2. 83 24 2. 85 79 2. 83 18 2. 86 82 2. 81 14 3. 01 64 2. 84 90 cv 1. 39 0. 29 2. 44 06 0* 1. 49 52 1. 49 75 1. 49 36 g eologia c roatica gverić et al.: comprehensive characterisation of bentonites from croatia and neighbouring countries 35 d i2 lv vb a d eg 55 0 °c li -2 00 -g ly m gg ly keg a d eg 55 0 °c li -2 00 -g ly m gg ly keg a d eg 55 0 °c li -2 00 -g ly m gg ly keg 00 1 15 .2 2 17 .4 6 10 .0 0 18 .0 7 18 .5 7 17 .2 7 15 .0 5 17 .3 3 10 .1 5 9. 70 18 .5 9 (1 5. 16 ) 16 .2 0 12 .9 (b , a ) 17 .1 3 9. 77 17 .8 5 18 .0 6 17 .2 6 00 2 8. 62 1 4. 84 9 9. 16 (b ) 9. 05 5 8. 64 8 8. 58 8 4. 82 7 4. 75 8 9. 16 2 6. 17 6 8. 52 1 4. 82 5 9. 35 7 8. 97 5 8. 68 3 00 3 5. 04 7 5. 65 9 6. 01 3 5. 65 8 4. 96 6 5. 65 1 6. 00 1 5. 66 7 5. 65 7 5. 95 5 5. 72 4 00 4 4. 28 9 4. 81 7 3. 12 33 4. 24 54 4. 60 6 4. 47 6 4. 31 47 00 5 3. 39 32 3. 42 99 2. 98 86 3. 38 63 3. 40 79 2. 48 81 3. 39 07 3. 44 31 00 6 2. 81 94 2. 86 36 2. 82 51 2. 83 94 2. 82 98 2. 86 27 cv 0. 74 2. 47 0. 42 06 0* 1. 49 75 1. 49 73 1. 49 67 pl a d eg 55 0 °c li -2 00 -g ly m gg ly keg 00 1 14 .9 5 17 .0 2 9. 84 9. 68 17 .8 2 17 .0 4 00 2 8. 49 6 4. 76 2 4. 70 5 8. 94 3 8. 71 6 00 3 4. 99 0 5. 63 6 3. 18 (b , a ) 5. 92 6 5. 68 2 00 4 4. 22 2 2. 50 00 5 3. 02 25 3. 37 89 1. 93 61 3. 55 91 3. 42 23 00 6 2. 81 83 2. 96 88 2. 86 27 cv 0. 94 06 0* 1. 49 75 *m ea su re d on ra nd om ly o rie nt ed sa m pl es (v al ue s i n pa re nt he se s i nd ic at e w ea ke r p ea k) b – br oa d a a sy m m et ric g eo lo gi a c ro at ic a geologia croatica 73/136 and zeolite from the heulandite-clinoptilolite series (table 2). opal-ct and quartz were also detected in the <2 µm fraction of some samples. both randomly oriented powder samples and ori­ ented clay-size mounts on glass slides showed that the main mineral in all of the samples is dioctahedral smectite (d060 ≈ 1.50 å) with small amounts of kaolinite present in some samples. smec­ tite was determined by a typical behaviour after eg treatment (d001 ≈ 17 å) and after heating at 400 and 550 °c (d001 ≈ 10 å) (fig. 2, table 3), while the first order kaolinite basal peak re­ mained unchanged around 7 å after eg treatment and heating to 400 °c, collapsing after heating to 550 °c. a couple of samples showed the presence of an amorphous substance (presumed to be volcanic glass), visible as a “hump” between and 20 and 30 °2θ, on both randomly oriented and oriented mounts. the greene-kelly test revealed the presence of beidellite in samples di1 (fig. 3), di2 and ši1. after prolonged treatment with glycerol, an additional shift to 18 å was observed for the vb and sj samples. mg-test confirmed the main mineral to be montmo­ rillonite in most of the samples (fig. 4a). some samples (lv, pr and sj) showed two peaks after glycerol treatment, one between 17 and 18 å and a smaller one (more prominent only in the case of the sj sample) around 14 å (fig. 4b, table 3). samples saturated with k and treated with eg showed either full expansion to about 17 å, negligible expansion with the 001 figure 4. xrd patterns of <2 µm fraction of samples exchanged with mg: (a) pl sample, before (grey) and after (black) glycerol solvation, showing behaviour typical for smectite and (b) lv sample showing the splitting of the 001 peak after the same treatment, cuka radiation. g eologia c roatica gverić et al.: comprehensive characterisation of bentonites from croatia and neighbouring countries 37 peak remaining around 14 å, or exhibited in-between values (ta­ ble 3, fig 5). observed d060 values were in the range of values for mont­ morillonite: 1.492 – 1.504 å (moore & reynolds, 1997) (table 3). 4.2. fourier transform infrared (ftir) spectroscopy results of the ftir analysis of the clay-size fraction (table 4) are in accordance with the xrd results. a well-defined 3700 cm-1 band, as well as the 795 and 753 cm-1 doublet (fig. 6) confirm the presence of kaolinite in some samples. the spectra also allowed figure 5. comparison of xrd patterns of (a) low(pr), (b) medium(lv), and (c) high-charged (ši1) smectites after k saturation and eg treatment of <2 µm fraction, cuka radiation. figure 6. ftir spectrum of di1 (<2 µm) sample with wave numbers of bands showing presence of kaolinite. g eo lo gi a c ro at ic a geologia croatica 73/138 a more detailed definition of some structural properties, e.g. cations in the octahedral coordination. the type of octahedrally coordinated cations pre­ sent in the smectite structure is visible from alaloh (915 cm-1), almgoh (840 cm-1) and alfeoh (885 cm–1) deformation bands (madejová & komadel, 2001) (fig. 7). all samples showed the alaloh band, while the presence of the almgoh and alfeoh bands varied (table 4). a broad band around 3420 cm-1 representing the oh stretching of water is visible on all spectra. after heating the kbr pellets, its intensity diminished, how­ ever its complete disappearance was not achieved. 4.3. cec determination cec of the samples varied between 44 and 94 cmol(+)/ kg with one sample from divoselo (di2) showing an anomalously low value of 19 cmol(+)/kg (table 5). 4.4. thermal analyses all of the samples show a single or double endothermic peak assigned to the dehydration process between 100 and 200 °c, as well as one or more endothermic peaks at higher temperatures, between 450 and 700 °c as­ signed to dehydroxylation (table 6). some samples show exothermic peaks around 450 °c indicating organic mat­ ter oxidation and/or above 900 °c due to recrystalliza­ tion (fig. 8). 4.5. chemical analysis the chemical composition of wr and of the <2 µm frac­ tion of the samples is shown in tables 7 and 8. data for the <2 µm fraction were used to calculate the chemical formula of smectite (table 9), while the wr chemistry, specifically the concentration of immobile elements, was used to deduce the composition of parent (volcanic) ma­ terial. 4.6. mössbauer spectroscopy mössbauer spectra recorded at room temperature differ significantly between samples (fig. 9, table 10). some of them (bu and ši1) could be fitted with a single dou­ blet characteristic for fe3+ in the octahedral coordina­ tion, while others had to be fitted with more doublets. spectra of ši2 and di1 were fitted with two doublets for fe3+ in the octahedral coordination, while for the rest of the samples (except bd) one additional doublet attributed to fe2+ in octahedral coordination had to be used. for the bd sample, the fit was made with four doublets, three previously mentioned and an additional one for fe3+ in tetrahedral coordination. assignment to different fe species was made in accordance with baron et al. (2017), pelayo et al. (2018) and references therein. there is no clear evidence of the presence of a magneti­ cally ordered phase, which indicates that most of the fe present in the fine fraction of the investigated smectites is incorporated into the smectite structure. 5. discussion 5.1. mineral and parent material composition the mineral composition of both the wr and clay-size fractions show the samples vary between almost monomineralic to polymineralic containing a number of ta bl e 4. a ss ig nm en ts o f f ti r ba nd s o bs er ve d in th e <2 µ m fr ac tio ns o f b en to ni te s ( af te r m a d ej o vá & k o m a d el , 2 00 1) . m nt – m on tm or ill on ite , k ln – k ao lin ite . w av en um be rs [ cm -1 ] a ss ig ne m en t bu zg bd d r ši 1 ši 2 sj pr d i1 d i2 lv vb pl 37 04 36 95 o h st re tc hi ng o f i nn er -s ur fa ce h yd ro xy l g ro up s ( kl n) 36 25 36 28 36 27 36 29 36 29 36 25 36 28 36 32 36 26 36 28 36 30 36 34 36 28 o h st re tc hi ng o f s tr uc tu ra l h yd ro xy l g ro up s ( m nt ) 16 30 16 30 16 31 16 31 16 32 16 27 16 22 16 29 16 26 16 27 16 31 16 22 16 27 o h d ef or m at io n of w at er 14 00 14 02 14 03 14 02 w ea k 14 01 14 02 n h 4 d ef or m at io n of n h 4b r 13 84 13 16 10 89 br oa d br oa d si -o st re tc hi ng o f c ris to ba lit e 10 30 10 39 10 27 10 35 10 36 10 37 10 37 10 48 10 38 10 47 10 39 10 44 10 39 si – o st re tc hi ng 91 3 91 3 in fle ct io n 91 5 91 2 91 5 91 8 92 0 91 2 91 8 91 6 91 6 91 6 a la lo h d ef or m at io n (m nt ) in fle ct io n 88 0 in fle ct io n 88 9 88 4 in fle ct io n 88 4 in fle ct io n 88 5 a lf eo h d ef or m at io n (m nt ) 84 3 84 2 in fle ct io n 84 3 83 8 84 5 in fle ct io n 84 7 85 2 84 5 in fle ct io n 84 9 a lm go h d ef or m at io n (m nt ) w ea k 80 0 w ea k 80 0 80 2 80 8 si -o st re tc hi ng o f q ua rt z an d si lic a 79 5 79 5 79 5 79 8 79 7 79 5 si -o st re tc hi ng o f c ris to ba lit e 79 8 79 3 si – o (k ln ) 78 2 75 3 75 3 si – o p er pe nd ic ul ar (k ln ) 69 7 69 2 si -o , p er pe nd ic ul ar 62 5 62 7 62 6 62 4 62 6 62 4 62 6 co up le d a l-o a nd s i-o , o ut -o f-p la ne ; s i-o o f c ris to ba lit e 60 7 52 0 52 9 52 3 52 0 52 7 52 2 52 5 52 5 53 3 52 5 52 2 52 5 52 1 a l – o – s i d ef or m at io n (m nt ) 46 6 47 2 47 0 47 0 46 8 46 7 47 0 46 8 46 9 46 7 46 7 46 9 46 7 si – o – s i d ef or m at io n (m nt ) 43 0 42 4 si – o d ef or m at io n g eologia c roatica gverić et al.: comprehensive characterisation of bentonites from croatia and neighbouring countries 39 additional minerals (table 2). smectite is the dominant mineral in the <2 μm fraction. kaolinite is present in 8 samples, and some silica minerals (quartz and/or opal-ct) remained in the <2 μm fraction after separation. the most problematic for further ana­ lyses was the presence of amorphous impurities (most likely vol­ canic glass) in samples zg, di1 and di2. the greene-kelly test showed the majority of samples con­ tain montmorillonite and only some (di1, di2 and ši1) could un­ ambiguously be classified as beidellite following their expansion after lithium saturation and glycerol treatment. for the other sam­ ples (sj, pr and vb) that showed swelling after the greene-kelly test, other analyses were not conclusive for the presence of beidel­ lite. the mg-test was even less conclusive and showed some sam­ ples (sj, pr and lv) retained (almost completely or partially) the 14 å peak position after glycerol treatment, even when other analyses showed that their layer charge was not high enough for vermiculite. this could be due to incomplete glycerol saturation, or the presence of interstratification of differently charged layers which was confirmed by the irrational order of the 00l series. the determined mineral composition of the samples is in overall good correlation with the existing literature data table 5. measured cec values (wr samples). sample cec [cmol(+)/kg] bu 60 zg 60 bd 85 dr 94 ši1 82 ši2 91 sj 78 pr 53 di1 64 di2 19 lv 85 vb 44 pl 72 figure 7. ftir spectrum of bd (<2 µm) sample with bands characteristic of the different octahedral cations indicated. table 6. observed temperatures of thermal reactions measured on <2 µm fractions of bentonites. sample dehydration temperature [°c] dehydroxylation temperature [°c] bu 105 + shoulder at 165 660 zg 125 + shoulder at 180 510 + weaker broad peak at 620 bd 110 broad peak below 600 + shoulder at 680 dr 105 peak at 635 + weaker broad peak at 480 ši1 110 + shoulder 180 485 ši2 135 + shoulder at 180 670 sj 125 + shoulder at 175 broad 670 + weak broad at 520 pr 120 + shoulder at 160 680 di1 100 + shoulder at 150 470 and a weak broad peak at 670 di2 110 + shoulder at 165 650 lv 120 + shoulder at 170 670 vb 120 + shoulder at 160 asymmetric peak at 670 with a shoulder at 610 pl 100 + shoulder at 155 660 g eo lo gi a c ro at ic a geologia croatica 73/140 (braun, 1991; marković, 2002; miladinović, 1976; vujnović, 1981), with the exception of beidellite found in sam­ ples from divoselo. ftir spectra provided more information on dioctahedral smectite in the samples and confirmed the presence of some min­ eral impurities (table 4). kaolinite was confirmed in samples zg and di1; however, it was not confirmed in other samples where xrd indicated its presence. the 3700, 3620 cm-1 doublet is char­ acteristic of the kaolin group, as well as oh deformation bands at 938 and 916 cm-1 (russell & fraser, 1994). in the inves­ tigated samples, the 3620 cm-1 band was overshadowed by a broad stretching band of the structural hydroxyl group in smectites and 938 and 916 cm-1 bands are probably also covered by smectite bands. the zg and di1 samples also showed two small bands around 795 and 753 cm-1 of roughly equal intensity, characteris­ tic for kaolinites (russell & fraser, 1994). silica impurities were also confirmed: a most notable band around 1090 cm-1 rep­ resenting si-o stretching of cristobalite in samples bu, vb and pl and 795 cm-1 in samples bu, ši2, di2, lv, vb and pl. quartz or silica, determined by a si-o stretching band at 800 cm-1 was found in samples bd, dr, pr and pl. some discrepancy between the content of impurities shown between xrd and ftir results could be the result of peak over­ lapping in recorded xrd patterns and ftir spectra and/or the presence of impurities in concentrations below the detection limit. this demonstrates the benefits of using both methods to complement each other. additionally, the thermal analysis showed an exothermal peak in the 450 °c region indicating pos­ sible presence of organic matter in some samples (bu, bd and pl) which have the highest tot/c. the mineral composition of the samples is the result of the parent material chemical composition. with that in mind, immo­ bile element (ti, zr, nb and y) content was used to determine parent material composition from the discrimination diagram af­ ter winchester & floyd (1977) (fig. 10). this diagram shows that most samples originate from acidic to neutral volcan­ oclastic material, with sample bd standing out as andesitic in composition. this can explain the highest fe content in the bd figure 8. dta curves of three representative samples, ši1, di1 and pl (<2 µm fractions) differing in dehydroxylation temperature range. in addition to endothermic peaks due to dehydration and dehyroxilation pl sample shows exothermal peak caused by organic matter oxidation while peaks due to recrystallization are visible on ši1 and di1 dta curves. ta bl e 7. c he m ic al c om po si tio n of w r sa m pl es . a na ly te u ni t m d l bu w r zg w r bd w r d r w r ši 1 w r ši 2 w r sj w r pr w r d i1 w r d i2 w r lv w r vb w r pl w r si o 2 % 0. 01 63 .6 6 49 .8 0 53 .7 5 53 .4 4 45 .5 5 51 .3 1 51 .4 2 52 .9 9 45 .1 2 64 .6 1 52 .5 9 65 .1 8 63 .1 9 a l 2o 3 % 0. 01 11 .0 1 21 .1 3 14 .0 3 15 .2 8 18 .2 8 17 .3 1 19 .8 5 18 .3 6 25 .7 8 14 .2 7 16 .7 7 13 .4 7 12 .4 6 fe 2o 3 % 0. 04 0. 73 2. 54 5. 93 3. 15 4. 35 1. 97 2. 78 4. 08 4. 4 2. 41 2. 36 2. 24 1. 7 m go % 0. 01 2. 78 3. 05 4. 15 4. 48 2. 25 3. 58 2. 43 2. 48 0. 77 0. 70 3. 62 1. 95 2. 27 ca o % 0. 01 4. 58 0. 97 1. 4 1. 52 5. 62 2. 44 2. 29 2. 87 1. 63 1. 40 1. 93 1. 70 2. 36 n a 2 o % 0. 01 0. 24 0. 01 1. 75 1. 01 0. 02 0. 04 0. 05 0. 61 0. 05 1. 74 0. 20 0. 67 0. 31 k 2 o % 0. 01 1. 28 0. 11 0. 88 0. 41 0. 26 0. 20 0. 39 0. 20 0. 12 3. 48 0. 53 0. 78 0. 35 ti o 2 % 0. 01 0. 11 0. 27 0. 63 0. 11 0. 53 0. 25 0. 29 0. 26 0. 22 0. 13 0. 20 0. 21 0. 09 p 2 o 5 % 0. 01 0. 02 <0 .0 1 0. 07 0. 02 0. 01 0. 05 0. 09 0. 11 0. 04 0. 01 0. 07 0. 05 0. 02 m no % 0. 01 <0 .0 1 <0 .0 1 0. 02 0. 01 0. 03 <0 .0 1 0. 01 0. 01 0. 04 0. 05 <0 .0 1 0. 04 <0 ,0 1 cr 2o 3 % 0. 00 2 0. 00 4 <0 .0 02 0. 00 4 0. 00 2 0. 00 8 <0 .0 02 <0 .0 02 <0 .0 02 0. 00 3 <0 .0 02 <0 .0 02 0. 00 3 0. 00 8 ba pp m 5 17 3 46 15 3 40 2 80 7 29 8 13 8 14 1 11 58 61 7 26 6 16 9 22 1 n i pp m 20 30 <2 0 21 <2 0 28 <2 0 <2 0 <2 0 <2 0 <2 0 <2 0 <2 0 35 sr pp m 2 56 60 35 0 24 0 16 6 30 40 12 6 21 44 11 8 31 2 15 8 zr pp m 5 88 20 8 19 1 10 5 24 2 16 1 13 4 16 7 41 7 23 9 28 0 90 13 8 y pp m 3 20 18 38 23 18 10 7 10 41 36 26 13 18 n b pp m 5 16 13 6 11 17 17 11 9 33 19 27 12 .3 12 sc pp m 1 3 6 14 5 12 5 4 4 20 11 4 4 7 lo i % -5 .1 15 .5 22 .0 17 .2 20 .4 22 .9 22 .7 20 .3 17 .9 21 .6 11 .0 21 .5 13 .6 17 .1 su m % 0. 01 99 .9 5 99 .9 0 99 .9 2 99 .9 1 99 .9 3 99 .8 6 99 .8 9 99 .8 7 99 .9 5 99 .8 6 99 .8 3 99 .8 8 99 .9 6 to t/ c % 0. 02 0. 71 0. 04 0. 31 0. 19 0. 98 <0 .0 2 0. 05 0. 18 0. 09 0. 02 0. 02 0. 11 0. 24 to t/ s % 0. 02 <0 .0 2 <0 .0 2 <0 .0 2 <0 .0 2 <0 .0 2 <0 .0 2 <0 .0 2 0. 02 <0 .0 2 <0 .0 2 <0 .0 2 <0 .0 2 <0 .0 2 m d l m et ho d de te ct io n lim it g eologia c roatica gverić et al.: comprehensive characterisation of bentonites from croatia and neighbouring countries 41 ta bl e 8. c he m ic al c om po si tio n of < 2 µm fr ac tio n. a na ly te u ni t m d l bu < 2 µm zg < 2 µm bd < 2 µm d r <2 µ m ši 1 <2 µ m ši 2 <2 µ m sj < 2 µm pr < 2 µm d i1 < 2 µm d i2 < 2 µm lv < 2 µm vb < 2 µm pl < 2 µm si o 2 % 0. 01 60 .5 5 50 .1 7 51 .1 3 53 .2 6 46 .7 7 50 .0 7 50 .2 2 52 .8 8 45 .2 52 .5 1 51 .5 3 62 .2 5 63 .2 6 a l 2o 3 % 0. 01 13 .2 8 22 .1 8 13 .8 5 15 .9 1 20 .4 7 17 .2 8 19 .7 8 17 .6 2 24 .5 6 17 .4 9 16 .8 4 14 .7 8 12 .3 3 fe 2o 3* % 0. 04 1. 41 2. 47 5. 61 3. 58 4. 99 2. 28 2. 37 3. 55 4. 68 3. 86 2. 27 2. 17 1. 58 fe o * % 0. 00 0. 11 0. 91 0. 47 0. 00 0. 00 0. 14 0. 28 0. 00 0. 32 0. 32 0. 12 0. 07 m go % 0. 01 3. 86 2. 98 4. 23 4. 03 2. 55 3. 59 2. 38 2. 57 0. 89 1. 94 3. 84 2. 19 2. 35 ca o % 0. 01 2. 29 0. 97 1. 33 1. 36 1. 66 2. 56 2. 49 2. 26 1. 71 2. 53 1. 96 2. 00 2. 39 n a 2 o % 0. 01 0. 10 0. 07 2. 74 1. 25 0. 01 0. 06 0. 08 0. 09 0. 09 0. 27 0. 12 1. 09 0. 17 k 2 o % 0. 01 1. 09 0. 11 0. 50 0. 80 0. 24 0. 17 0. 16 0. 07 0. 15 0. 62 0. 31 0. 22 0. 20 ti o 2 % 0. 01 0. 12 0. 25 0. 64 0. 20 0. 42 0. 25 0. 18 0. 14 0. 18 0. 16 0. 18 0. 08 0. 08 p 2 o 5 % 0. 01 <0 .0 1 <0 .0 1 0. 06 0. 07 0. 02 <0 .0 1 <0 .0 1 <0 .0 1 0. 02 <0 .0 1 0. 02 <0 .0 1 <0 ,0 1 m no % 0. 01 <0 .0 1 <0 .0 1 0. 02 0. 02 0. 02 <0 .0 1 <0 .0 1 <0 .0 1 0. 03 0. 05 <0 .0 1 0. 02 <0 ,0 1 cr 2o 3 % 0. 00 2 0. 00 6 <0 ,0 02 0. 00 4 0. 01 1 0. 00 9 <0 ,0 02 <0 ,0 02 <0 ,0 02 <0 ,0 02 <0 ,0 02 <0 ,0 02 <0 ,0 02 <0 ,0 02 ba pp m 5 72 50 26 4 32 8 15 4 62 64 67 10 92 17 6 10 3 24 16 0 n i pp m 20 62 <2 0 <2 0 31 32 <2 0 <2 0 <2 0 21 <2 0 <2 0 <2 0 <2 0 sr pp m 2 28 59 25 1 18 3 15 5 28 35 78 24 22 11 8 26 9 15 2 zr pp m 5 81 23 2 20 2 97 16 5 99 57 84 27 0 23 4 20 8 68 10 3 y pp m 3 19 20 34 21 15 9 5 8 32 27 23 7 13 n b pp m 5 21 13 6 12 17 16 7 7 14 25 29 9 10 lo i* * % -5 .1 17 .2 20 .6 18 .6 18 .8 22 .7 23 .6 22 .1 20 .4 22 .3 20 .1 22 .4 15 .0 17 .5 su m % 0. 01 99 .9 2 99 .8 9 99 .9 1 99 .9 2 99 .9 3 99 .9 0 99 .9 3 99 .9 1 99 .9 3 99 .8 7 99 .8 5 99 .9 0 99 .9 6 to t/ c % 0. 02 0. 25 0. 14 0. 44 0. 24 0. 15 0. 05 0. 13 0. 19 0. 14 0. 25 0. 08 0. 35 0. 40 to t/ s % 0. 02 <0 .0 2 <0 .0 2 <0 .0 2 <0 .0 2 <0 .0 2 0. 02 <0 .0 2 <0 .0 2 <0 .0 2 <0 .0 2 <0 .0 2 0. 06 <0 .0 2 * va lu es c al cu la te d ac co rd in g to m ös sb au er sp ec tr a ** va lu e co rr ec te d fo r f eo ta bl e 9. c al cu la te d ch em ic al fo rm ul ae o f i nv es tig at ed b en to ni te sa m pl es . sa m pl es bu zg bd d r ši 1 ši 2 sj pr d i1 d i2 lv vb pl co rr ec tio ns -2 5% o pa l-c t -1 0% k ao lin ite -1 % c al ci te -1 % k ao lin ite -2 % q ua rt z -1 % q ua rt z -1 % k ao lin ite -1 0% k ao lin ite -2 0% o pa l-c t -2 5% o pa l-c t te tr ah ed ra l ca tio ns si 3. 72 a l 0. 28 si 3. 80 a l 0. 20 si 3. 91 fe 3+ 0. 03 a l 0. 06 si 3. 91 a l 0. 09 si 3. 62 a l 0. 38 si 3. 89 a l 0. 11 si 3. 82 a l 0. 18 si 3. 94 a l 0. 06 si 3. 54 a l 0. 46 si 3. 93 a l 0. 07 si 3. 94 a l 0. 06 si 3. 88 a l 0. 12 si 3. 95 a l 0. 05 ch ar ge (% o f t ot al la ye r c ha rg e) -0 .2 8 (3 5% ) -0 .2 0 (4 3% ) -0 .0 9 (1 5% ) -0 .0 9 (1 7% ) -0 .3 8 (6 7% ) -0 .1 1 (2 2% ) -0 .1 8 (4 0% ) -0 .0 6 (1 6% ) -0 .4 6 (9 4% ) -0 .0 7 (2 3% ) -0 .0 6 (1 3% ) -0 .1 2 (2 8% ) -0 .0 5 (1 2% ) o ct ah ed ra l ca tio ns a l 1. 36 f e3+ 0. 11 m g 0 .5 3 a l 1. 59 f e3+ 0. 15 fe 2+ 0. 01 m g 0 .2 5 a l 1. 17 fe 3+ 0. 30 fe 2+ 0. 06 m g 0 .4 7 a l 1. 34 f e3+ 0. 21 fe 2+ 0. 03 m g 0 .4 2 a l 1. 51 f e3+ 0. 30 m g 0 .1 9 a l 1. 47 fe 3+ 0. 13 m g 0 .4 0 a l 1. 59 fe 3+ 0. 14 fe 2+ 0. 01 m g 0 .2 6 a l 1. 49 f e3+ 0. 20 fe 2+ 0. 02 m g 0 .2 9 a l 1. 66 f e3+ 0. 31 m g 0 .0 3 a l 1. 47 fe 3+ 0. 22 fe 2+ 0. 02 m g 0 .2 2 a l 1. 46 fe 3+ 0. 13 fe 2+ 0. 02 m g 0 .3 9 a l 1. 48 fe 3+ 0. 15 f e2+ 0. 01 m g 0 .3 0 a l 1. 45 f e3+ 0. 12 fe 2+ 0. 01 m g 0 .3 6 su m o f o ct ah ed ra l c at io ns 2. 00 2. 00 2. 00 2. 00 2. 00 2. 00 2. 00 2. 00 2. 00 1. 93 2. 00 1. 94 1. 94 ch ar ge (% o f t ot al la ye r c ha rg e) -0 .5 3 (6 5% ) -0 .2 6 (5 7% ) -0 .5 3 (8 5% ) -0 .4 5 (8 3% ) -0 .1 9 (3 3% ) -0 .4 0 (7 8% ) -0 .2 7 (6 0% ) -0 .3 1 (8 4% ) 0. 03 (6 % ) -0 .2 4 (7 7% ) -0 .4 1 (8 7% ) -0 .3 1 (7 2% ) -0 .3 7 (8 8% ) to ta l l ay er c ha rg e (t +o ) -0 .8 1 -0 .4 6 -0 .6 2 -0 .5 4 -0 .5 7 -0 .5 1 -0 .4 5 -0 .3 7 -0 .4 9 -0 .3 1 -0 .4 7 -0 .4 3 -0 .4 2 in te rla ye r ca tio ns ca 0. 26 m g 0 .0 7 n a 0 .0 2 k 0. 15 ca 0. 09 m g 0 .1 2 n a 0 .0 1 k 0 .0 1 ca 0. 06 m g 0 .0 2 n a 0 .4 1 k 0. 05 ca 0. 11 m g 0 .0 4 n a 0 .1 8 k 0. 08 ca 0. 14 m g 0 .1 1 k 0 .0 2 ca 0. 21 m g 0 .0 2 n a 0 .0 1 k 0. 02 ca 0. 20 m g 0 .0 1 n a 0 .0 1 k 0 .0 2 ca 0. 18 n a 0 .0 1 ca 0. 16 m g 0 .0 9 n a 0 .0 2 k 0. 02 ca 0. 20 n a 0 .0 4 k 0 .0 6 ca 0. 16 m g 0 .0 5 n a 0 .0 2 k 0. 03 ca 0. 20 n a 0 .1 9 k 0 .0 3 ca 0. 26 n a 0 .0 3 k 0. 03 ch ar ge +0 .8 3 +0 .4 4 +0 .6 2 +0 .5 6 +0 .5 2 +0 .4 9 +0 .4 5 +0 .3 7 +0 .5 4 +0 .5 0 +0 .4 7 +0 .6 2 +0 .3 2 g eo lo gi a c ro at ic a geologia croatica 73/142 sample. the initial hypothesis that the samples containing beid­ ellite, and thus less sio2, originate from more basic material was not confirmed. still, in the case of altered pyroclastic rocks, elemental analyses should be taken cautiously as different materials could have been deposited in the same basin. moreover, the volcanic material could have been separated during transport, especially in the case of distant depositional basins, which is mostly the case for the studied samples. figure 9. mössbauer spectra of (a) bu and (b) bd samples (<2 µm) recorded at room temperature. a b g eologia c roatica gverić et al.: comprehensive characterisation of bentonites from croatia and neighbouring countries 43 5.2. crystallo-chemical properties of the investigated smectites and their classification some trends could be observed regarding the chemical composi­ tion of the investigated smectites (tables 7 and 8): the main ele­ ments did not show large variation between wr and the <2 µm fraction with the exception of a much higher calcium concentra­ tion in wr of bu and ši1 samples, due to calcite presence. among microelements, zirconium, usually present in zircon which is expected in the silt fraction, is more abundant in the wr, as well as strontium which can replace calcium in calcite and pla­ gioclase. in contrast, the ni and fe concentrations showed nega­ tive correlation with particle size. structural chemical formulae calculated from the chemical composition of samples’ <2 μm fractions could be compromised with crystalline and especially amorphous impurities present (brigatti, 1983). therefore, the resulting chemical formulae (table 9) represent an approximate distribution of cations in the smectite structure. they can show some chemical and structural features of the smectite, such as layer charge, its distribution and the chemical composition of the octahedral sheet. nevertheless, additional analyses were used to confirm (or disprove) these. some calculated formulae show inconsistencies, e.g. charge im­ balance or divergence from the results of other analyses. for ex­ ample, the calculated layer charge for bu and, to lesser extent, for bd samples is too high for smectites, yet the mg­test did not show the presence of vermiculite in those samples. samples di2 and vb have a significant discrepancy between their calculated layer charge and the interlayer cations compensating for it, which could be explained by the presence of amorphous impurities in the di2 sample, but remains speculative in the case of the vb sample. according to the chemical composition, the dominant cation in the interlayer is ca for most samples, except bd and dr where na is more abundant and vb in which both cations are equally represented. in the zg sample, the calculated structural formula would suggest mg is the dominant interlayer cation; however we cannot be sure of the accuracy of the formula due to amorphous impurities detected in this sample, it is probably more likely ca as well (držaj & lukacs, 1968). there are a number of smectite classification schemes in the existing literature (grim & kulbicki, 1961; schultz, 1969; brigatti & poppi, 1981) taking into account different criteria, such as layer charge, chemical composition and structure. emmerich et al. (2009) proposed a new classification scheme, in order to account for many discrepancies between known samples of bentonites not fitting into historical classifica­ tion criteria, based on the following groups of analytical data: – layer charge, – structure of the octahedral sheet, – iron content, and – charge location. these four criteria were used to further describe the smec­ tite in the investigated bentonites. figure 10. content of immobile elements in analyzed bentonites plotted on the diagram for determination of original composition of altered rocks (winchester & floyd, 1977). table 10. mössbauer parameters obtained from the fit of the mössbauer spectra recorded at room temperature on the studied smectites [mm/s], assignment to different fe-species and their relative concentrations. width is expressed as half width at half maximum (hwhm), isomer shift is specified relative to α-fe. fe3+ (vi) (a) fe3+ (vi) (b) fe2+ (vi) fe3+ (iv) δ δ width area δ δ width area δ δ width area δ δ width area sample [mm/s] [mm/s] [mm/s] [%] [mm/s] [mm/s] [mm/s] [%] [mm/s] [mm/s] [mm/s] [%] [mm/s] [mm/s] [mm/s] [%] bu 0.35 0.48 0.23 100.0 zg 0.36 0.53 0.25 61.0 0.36 1.00 0.48 35.0 1.06 2.69 0.42 4.8 bd 0.37 0.45 0.20 33.3 0.40 1.10 0.37 44.1 1.10 2.73 0.20 15.3 0.19 0.57 0.18 7.4 dr 0.35 0.43 0.26 63.4 0.39 1.24 0.30 23.9 1.13 2.66 0.22 12.7 ši1 0.36 0.50 0.27 100.0 ši2 0.36 0.52 0.17 52.0 0.36 0.87 0.38 48.0 sj 0.36 0.52 0.20 58.0 0.38 1.08 0.36 36.0 1.11 2.57 0.30 6.0 pr 0.34 0.68 0.33 88.2 0.67 1.11 0.13 3.8 0.97 2.81 0.37 8.0 di1 0.35 0.51 0.22 72.0 0.39 0.96 0.39 28.0 di2 0.35 0.54 0.22 68.3 0.45 1.19 0.33 23.2 0.99 2.68 0.37 8.5 lv 0.35 0.43 0.23 50.0 0.38 1.11 0.39 36.0 1.16 2.82 0.22 13.5 vb 0.33 0.46 0.28 49.0 0.41 0.94 0.51 45.0 1.12 2.82 0.18 5.9 pl 0.35 0.58 0.26 48.0 0.36 1.09 0.44 47.0 1.30 2.40 0.14 4.9 s – broad peak with shoulder g eo lo gi a c ro at ic a geologia croatica 73/144 according to emmerich et al. (2009) the interlayer cations are not considered for classification, nevertheless the descriptive name can be extended with respect to the original or exchanged interlayer cations, which, on one hand indicate conditions during smectite formation, and on the other, are responsible for its prop­ erties. 5.2.1. layer charge the layer charge was determined using both calculated and ob­ served data, bearing in mind that chemical formulae calculations are affected by the presence of impurities in the samples. the layer charge from the calculated chemical formulae showed most samples are in the medium charge range, with values 0.31-0.54 per formula unit (fu) or half unit cell, with a few exceptions: ši1 (0.57), bd (0.62), and especially bu (0.81). smectites are defined as 2:1 phyllosilicates with expandable layers and a layer charge between approximately 0.2 and 0.6/fu (guggenheim et al., 2006); therefore, bu would not satisfy that criteria. however, due to the already mentioned difficulties in obtaining an accurate chemical formula, and thus a calculated layer charge, the empha­ sis is put on the swelling behaviour of mg-saturated samples treated with glycerol when it comes to differentiation between smectites and vermiculites. all of the investigated samples (in mg-form), except sj and partly pr and lv swelled after glycerol solvation, even if for some of them (bd and bu were not among them) a longer time was necessary for full swelling. the sj sam­ ple, which is medium charged according to both its chemical for­ mula and swelling behaviour of k-saturated form, showed split­ ting of the 001 peak: only a small portion of the peak moved to 17.6 å while the majority remained at 14.0 å. samples saturated with k and treated with eg showed either full expansion to about 17 å, negligible expansion (001 peak re­ maining around 14 å) or showed in-between values. accordingly, based on the layer charge inferred from such swelling be­ haviours samples can be divided into three groups: those with low layer charge expanding fully, those with high layer charge (non-expanding) and the samples showing in-between values and an irrational series of 00l peaks. coefficient of variation (cv) of d00l values for k-saturated samples analysed after eg treatment were used to determine the stacking order of the clay mineral layers. fully expandable samples, i.e. those with low-charge lay­ ers (pr, vb, di2 and pl) exhibit a rational order of basal peaks and have a cv below or slightly above 0.75% (value defined by bailey, 1982) indicating periodic stacking of layers. samples with expansion behaviour that suggests their layers are medium to high-charged show an irrational order of basal peaks and higher cv values (table 3). číčel & machajdík (1981) in­ vestigated the three types of layers (expandable, partly expandable and non-expandable) in smectites saturated with monovalent ions with low solvation energy and concluded they are most com­ monly randomly distributed in the minerals. likewise, the over­ all conclusion drawn about the layer charge approximations (also applicable to the results of greene-kelly and mg-test) is that the studied samples may not be homogeneous, i.e. they could consist of different layers and thus show intermediate properties. this would explain the inconclusive behaviour in different analyses and can be backed up by evidence of cv values which suggest an irrational order sequence in 9 out of 13 samples. it should be noted however that cv values should be calculated on at least 10 basal peaks (bailey, 1982) which were not all present in this case. furthermore, cv calculations are strongly influenced by inaccurate reading (done by software profile fitting), of the 001 peak position, which is especially true for wider peaks in the case of inhomogeneous samples with a small number of smectite lay­ ers in stacks. there are a few samples (most notably ši1) where there is a discrepancy between the calculated and observed layer charge (fig. 11), so for the purposes of classification the observed (in­ ferred) layer charges were used, on account of the fact that the chemical data could be compromised with mineral and amor­ phous impurities. when comparing the calculated tetrahedral and octahedral charge with the observed swelling behaviour, the samples largely follow the trend postulated by sato et al. (1992) (fig. 12). on their diagram, sample ši1, with a higher charge in the tetrahedral sheet, which notably deviated from the linear correlation of cal­ culated and inferred layer charge (fig. 11) shows behaviour in accordance with the theory that swelling depends not only on the total layer charge but also on its location. cec was measured on wr rather than clay-size fractions since all the investigated bentonites are pure enough to not have figure 11. the relationship between calculated and inferred layer charge (after eg-swelling behaviour of k-exchanged samples i.e. observed d001) showing relatively good correlation, with some outliers (notably ši1). figure 12. octahedral and tetrahedral sheet charge and observed swelling behaviour of k-saturated <2 μm sample fractions after eg solvation plotted on the diagram by sato et al. (1992). white circles – samples fully expanding to about 17 å; black dots – negligibly expanding samples with 001 peak remaining around 14 å; black squares –samples showing in-between values. g eologia c roatica gverić et al.: comprehensive characterisation of bentonites from croatia and neighbouring countries 45 to be treated before prospective applications. several samples show cec values (table 5) lower than those expected for smec­ tites. meier & nüesch (1999) denoted the lower cec limit to be 65 ± 2 cmol(+)/kg; however some samples are even lower than this limit. in this case the issue is most likely due to the fact that wr samples contain variable amounts of mineral and amor­ phous phases which do not contribute to the cec. 5.2.2. structure of the octahedral sheet when it comes to the octahedral sheet structure, chemical data indicate aluminium abundance. xrd analysis, done on randomly oriented clay-size fraction in the 59 – 65 °2θ region, showed all the investigated clay minerals to be dioctahedral (table 3). additional cations occupying the octahedral sheet are ferric, ferrous and magnesium cations; the last two contributing to the octahedral charge. the oh vibrations visible in the ftir spectra are affected by the octahedral cations to which the oh group is coordinated (petit, 2006). the octahedral cation occupancy can be deduced from characteristic bands: around 920 cm-1 for alaloh, 885 cm-1 for alfeoh and 845 cm-1 for almgoh. there is a correlation between the octahedral charge and the prominence of the different bands. beidellites (di1, di2 and ši1) have a more prominent alaloh band and other less prominent bands, while samples with a higher number of octahedral substitutions show other more prominent bands. samples with a higher amount of octahedral fe (e.g. bd) can also be distinguished from the ftir spectra. thermal analyses performed on clay-size samples provided additional information about the structure of the octahedral sheet. the nature of octahedral cations and their bonding strength affect the endothermic peak position. the dehydroxylation temperature increases as fe–oh < al–oh < mg–oh (köster, 1993). drits et al. (1995) showed that the temperature depends not only on the mineral species, but also on the position of vacant octahe­ dra in dioctahedral clay minerals. they set the limit of the dehy­ droxylation peak temperature discriminating between a trans­va­ cant and cis-vacant octahedral sheet at 600 °c. this means that ideal trans-vacant (tv) montmorillonites should lose their ohgroups below 600 and ideal cis-vacant (cv) montmorillonites above 600 °c. wolters & emmerich (2007) expanded on this and postulated a model for estimating the tv and cv sheets in a given sample. komadel & madejová (2010) stated that beidellitic samples would show a lower dehydroxylation tempera­ ture, i.e. more trans­vacant sites. dehydroxylation temperatures varied significantly between the analysed samples with some samples showing multiple dehy­ droxylation peaks (table 6). generally speaking “ideal” montmo­ rillonites lose their structural water in the 700 °c region, while “ideal” beidellites have their main dehydroxylation peak below 550 °c (greene-kelly, 1953). the fact that some samples can­ not be attributed to either group shows that some of the samples are “non-ideal”, i.e. structurally inhomogeneous. a small number of samples and their low fe content did not allow determination of the influence of fe on the dehydroxylation temperature. in the present study, the peak modelling of the mass-spec­ trometer curves of evolved water proposed by wolters & em­ merich (2007) was not used; however, by observing the peak dehydroxylation temperature it was possible to deduce the pre­ dominant nature of the octahedral sheets (table 6). the samples in which the dehydroxylation peak was below 550 °c show an exothermic peak around 900 °c attributed to the recrystallization process. 5.2.3. iron content bd is the only sample in which fe made up a considerable pro­ portion of the octahedral cations (almost 20%) and is considered ferrian. samples coming close to the limit of 15% percent of the octahedral positions occupied by fe ions are di1 and ši1; how­ ever, those would not be considered ferrian, noting as well that other samples taken from the same deposits (di2 and ši2) do not follow the same trend. information about fe speciation, its oxidation state and co­ ordination, is necessary for the correct structural formula calcu­ lations. in this study, mössbauer spectroscopy was used to pro­ vide the required data (table 10). it showed that fe2+ is present in the majority of samples (9 out of 13). its content is small but in some samples not negligible (> 10 % of total fe). there is no ev­ ident relationship between the geological environment (lacustrine or marine) and the total iron or fe2+ content. traditionally, in for­ mula calculations, only al for si substitutions have been ac­ counted for, mostly due to the smaller ion size of al in compari­ son with fe3+, but also due to the difficulties with ivfe3+ measurement, which persist even in mössbauer spectroscopy analyses. gates et al. (2002) concluded that tetrahedral fe3+ is unlikely to be present in smectites with < 34 wt% fe2o3 but kaufhold et al. (2017) found tetrahedral fe3+ even in sam­ ples containing 2.1 wt% fe2o3. in sample bd with 6.6 wt% (the highest fe content among analysed samples) fitting of mössbauer spectra revealed that 7.4 % of the total iron is present in the tet­ rahedral coordination. nevertheless, it must be said that for this sample a reasonable fit could also be obtained without the doublet corresponding to ivfe3+. some of the spectra showed only one or one dominant dou­ blet (with a quadrupole splitting value in the range 0.43-0.68 mm/s) characteristic for fe3+ in the octahedral coordination. for others, an additional doublet attributed to fe3+ in the octahedral coordination (with a quadrupole splitting value ranging between 0.87 and 1.24 mm/s) had to be used. some authors attribute (e.g. coey, 1980) these two doublets to fe3+ in octahedral cis­ and transpositions, respectively. several authors (baron et al., 2017; pelayo et al., 2018 and references therein) doubt this in­ terpretation. the studied samples speak in favour of the latter: both bu and ši1 samples have only the first doublet and accord­ ing to the thermal properties the first is cis-vacant while the sec­ ond is trans-vacant. other authors (pelayo et al., 2018 and ref­ erences therein) relate these doublets to less and more distorted octahedral environments. pelayo et al. (2018) attribute distor­ tion to the substitution of al with fe but for the studied samples no correlation of total iron content and % area of the second dou­ blet was observed. sometimes, a reliable structural formula calculation, includ­ ing proper iron content evaluation, is problematic due to impuri­ ties, especially amorphous ones. in such cases, relationships be­ tween chemical and physical properties are used to evaluate the content of an element of interest. an example of such physical properties, which can be easily measured, are unit-cell dimen­ sions. it is known that the length of the b­unit cell edge is corre­ lated with structural fe content (radoslovich, 1962; brig­ atti, 1983; köster et al., 1999; heuser et al., 2013). for the analysed set of samples, most of which have a low iron content, no correlation of fe content and b­unit cell dimen­ sion was observed (fig. 13). there are several possible explana­ tions for this. such a lack of correlation can be caused by inac­ curate structural formulae resulting from impurities present in the sample, e.g. the very low unit cell dimension for given fe g eo lo gi a c ro at ic a geologia croatica 73/146 content for di2 sample could be because of the presence of amor­ phous material. another source of error could be the calculation of the b­unit cell dimension by multiplying d060, since the ob­ served reflection is not a single one (desprairies, 1983). the lack of correlation could also be explained by the fact that the b-dimension does not depend only on iron content (ra­ doslovich, 1962), and that for low iron content other factors (octahedral mg and tetrahedral al content) can be more impor­ tant. this is in agreement with the results by brigatti (1983) who stated that correlation of the b-unit cell edge with the struc­ tural fe content is valid only for samples with an iron content > 0.50 atoms per half-cell and none of the analysed samples ful­ fil that requirement. heuser et al. (2013) also observed poorer correlation for samples with low fe contents. in contrast, köster et al. (1999) do not mention the lack of correlation; however, their regression was determined on only five samples of nontronites and fe­rich smectites. observed b-unit cell dimensions were compared with those calculated using different regressions (table 11, fig. 14). there is a poor correlation between the observed and calculated values for the regression of köster et al. (1999), which takes only the in­ fluence of fe into account. better correlation was observed for values calculated using the regression of radoslovich (1962), which takes into account other substitutions; however, all calculated values are greater than those observed. 5.2.4. charge location overall (with the exceptions of the sj, vb and di2 samples), the greene-kelly test results are in accordance with the distribution of layer charge which can be observed from the calculated chemical formulae. they are also predominantly in accordance with the observed dehydroxylation temperatures which are, as ex­ pected, lower for beidellitic samples (komadel & made­ jová, 2010). based on the distribution of the layer charge between octa­ hedral and tetrahedral sheets, smectites can be divided into mont­ morillonites (90–100% of charge originating in octahedral sheet – o), beidellitic montmorillonites (50–89% o), montmorillonitic beidellites (10–49% o) and beidellites (0–9% o) (emmerich et al., 2009). most of the studied samples fall into the “beidellitic mont­ morillonite” category, even though their octahedral charge ranges from 57, which is close to “montmorillonitic beidellite” to 88% o which is very close to “montmorillonite”. only di1 and ši1 can be classified as beidellite and montmorillonitic beidellite, re­ spectively. those two samples are also the only ones consistently showing the higher amount of tetrahedral charge, i.e. other analyses (chemistry, dta) are in accordance with their beidellitic nature. 5.2.5. interlayer cations chemical analysis and subsequent formula calculation (table 9) show that ca is the dominant interlayer cation in the majority of the investigated bentonites. na is dominant only in two samples (bd and dr), while one sample (vb) shows an approximately equal ratio of ca and na in the interlayer. the sample zg shows quite large quantities of mg in the interlayer, though this could be a miscalculation due to amorphous impurities (volcanic glass) present in the sample. dta results largely confirm the chemical data when it comes to the interlayer cations. the majority of samples (except bd and dr) show a two-step dehydration process. this is in accordance with the fact that in both the bd and dr samples na is the dominant interlayer cation. according to greene-kelly (1953) and schultz (1969), na-smectites show a single endotherm peak around 100-150 °c, while ca-smectites have two distinct endotherm peaks. according to greene-kelly (1953) this is the result of the premature loss of water during dehydration caused by limited stability of the monolayer na-smectite com­ plex. in the vb sample in which chemical analysis determined na and ca in the interlayer, two distinct peaks are visible, though the higher temperature one is very small. samples with na cations in the interlayer showed an addi­ tional endothermic peak at around 850 °c. the presence of an nh4br deformation band in ir spectra of some samples indicates nh4 + ions in their interlayer (made­ jová & komadel, 2001). 6. conclusions thirteen bentonite samples from eleven known deposits in cro­ atia, bosnia and herzegovina, serbia and slovenia contain dioctahedral smectite as the main component. some of them are al­ most monomineralic while others contain a number of additional phases (kaolinite, illite, quartz, opal-ct, plagioclase feldspars, calcite, zeolite from the heulandite-clinoptilolite series, amor­ phous impurities, and organic matter), some of those also being present in the <2 μm fraction. figure 13. correlation of b-unit cell dimension and number of fe ions obtained by structural formula calculation. figure 14. correlation of observed and calculated b-unit cell dimension (black dots – regression of radoslovich, 1962; gray dots – regression of köster et al., 1999). g eologia c roatica gverić et al.: comprehensive characterisation of bentonites from croatia and neighbouring countries 47 smectites show prominent variations in their crystallochemical properties resulting in different bentonite properties. they were classified (table 12) according to the newest classifi­ cation scheme proposed by emmerich et al. (2009) based on: – layer charge – both swelling properties of k-saturated sam­ ples and calculated structural formulae showed (in spite of some discrepancies) that samples ranged from those with low layer charge to those with high-layer charge but most are medium to low-charged. results showed that samples are most probably not homogeneous, i.e. they consist of layers of different charges. – octahedral sheet structure – all investigated smectites are dioctahedral. ir spectra and chemical analyses showed variations in the al, fe and mg content of the octahedral sheet. dehydroxylation temperature, as a proxy for the location of the vacancy in the octahedral sheet (tv vs. cv) varied significantly between the samples with some samples showing multiple dehydroxylation peaks indicating that some of the samples are structurally inho­ mogeneous. – iron content – most of the samples are non-ferrian. the ex­ ceptions are bd in which fe accounts for almost 20% of the oc­ tahedral cations, and di1 and ši1 samples which are close to the limit defined as 15% percent of the octahedral positions occupied by fe ions. in the mössbauer spectrum of the bd sample there is an indication of fe3+ in tetrahedral coordination. mössbauer spec­ troscopy showed that fe2+ is present in the majority of samples (9 out of 13). its content is small but in some samples not negli­ gible (> 10 % of total fe). overall, mössbauer spectra differ sig­ nificantly between samples. – charge location – calculated structural formulae, which are in accordance with the results of greene-kelly tests and ftir spectroscopy, showed that most of the samples fall into the “bei­ dellitic montmorillonite” category, even though their octahedral charge ranges from 57%, which is close to “montmorillonitic bei­ dellite” to 88% o (pl sample) which is very close to “montmo­ rillonite”. samples di1 and ši1 contain “beidellite” and “mont­ morillonitic beidellite, respectively. – type of interlayer cation the dominant cation in the inter­ layer is ca for most samples, except bd and dr where na is more abundant and vb in which both cations are present in approxi­ mately equal amounts. acknowledgment the research has been financially supported by the 119-11911551156 project of the croatian ministry of science and education, research program p1–0112 by slovenian research agency, and annual support over several years from the university of zagreb. the authors are grateful to dobroslav supan†, stanislav međimorec, franjo percela, frane marković and vanja biševac for their help in providing samples and to dražan jozić (university of split, faculty of chemistry and technology) and dominik cinčić (university of zagreb, faculty of science, department of chemistry) for recording thermal curves. the authors also express their gratitude to anita grizelj and an anonymous reviewer for their valuable constructive comments and suggestions. references avanić, r. (2012): litostratigrafske jedinice donjeg miocena sjeverozapadne hrvatske [lower miocene lithostratigraphic units from north-western croatia – in croatian with english summary].– unpl. phd thesis, faculty of science, university of zagreb, 162 p. bailey, s.w. (1982): nomenclature for regular interstratifications.– am. mineral., 67, 394–398. doi: 10.1180/claymin.1982.017.2.09 baron, f., petit, s., pentrák, m., decarreau, a. & stucki, j.w. (2017): revisiting the nontronite mössbauer spectra.– am. mineral., 102, 1501–1515. biševac, v., šegvić, b., tibljaš, d. & lugović, b. (2007): mineralogy of al­ tered tephra layers in the upper jurassic lemeš deposits near maovice (dalmatia, croatia).– in: rocha, f., terroso, d. & quintela, a. (eds.): euroclay 2007, abstract book. university of aveiro, aveiro, 75–76. braun, k. (1991): mineraloško-petrografske karakteristike i geneza ležišta bentonit­ nih glina maovica, gornje jelenske, bednje i poljanske luke [mineralogical-petrographical characteristics and genesis of the bentonite deposits of maovice, gornja jelenska, bednja and poljanska luka – in croatian, with an english ab­ stract].– prirodoslovna istraživanja, 63, acta geol., 21/1, 1–34. brigatti, m.f. (1983): relationship between composition and structure in fe-rich smectites.– clay miner., 18, 177–186. doi: 10.1180/claymin.1983.018.2.06 brigatti, m.f. & poppi, l. (1981): a mathematical model to distinguish the mem­ bers of the dioctahedral smectite series.– clay miner., 16, 81–89. doi: 10.1180/ claymin.1981.016.1.06 brindley, g.w. & brown, g. (1980): the x-ray identification and crystal structures of clay minerals.– mineralogical society, london, 495 p. doi: 10.1180/mono-5 brown, g. (1961): the x-ray identification and crystal structures of clay minerals.– mineralogical society, clay minerals group, london, 544 p. christidis, g.e. & eberl, d.d. (2003): determination of layer charge characteristics of smectites.– clay. clay miner., 51, 644–655. doi: 10.1346/ccmn.2003.0510607 číčel, b. & machajdík, d. (1981): potassiumand ammonium-treated montmoril­ lonites. i. interstratified structures with ethylene glycol and water.– clay. clay miner., 29, 40–46. doi: 10.1346/ccmn.1981.0290106 coey, j.m.d. (1980): clay minerals and their transformations studied with nuclear tech­ niques: the contribution of mössbauer spectroscopy.– atom. energy rev., 18, 73–124. desprairies, a. (1983): relation entre le parametre b des smectites et leur contenu en fer et magnesium. application a l’etude des sediments.– clay miner., 18, 165–175. doi: 10.1180/claymin.1983.018.2.05 table 12. proposed descriptive names of the smectite mineral dominant in the investigated samples, following classification criteria proposed by emmerich et al. (2009). sample proposed descriptive name bu ca-saturated high-charge cv beidellitic montmorillonite zg mg,ca-saturated medium-charge tv/cv beidellitic montmorillonite bd na-saturated medium-charge ferrian tv/cv beidellitic montmorillonite dr nasaturated medium-charge cv/tv beidellitic montmorillonite ši1 ca,mgsaturated high-charge tv montmorillonitic beidellite ši2 casaturated medium-charge cv beidellitic montmorillonite sj casaturated medium-charge cv/tv beidellitic montmorillonite pr casaturated low-charge cv beidellitic montmorillonite di1 casaturated medium-charge tv/cv beidellite di2 casaturated low-charge cv beidellitic montmorillonite lv casaturated medium-charge cv beidellitic montmorillonite vb ca,nasaturated low-charge cv beidellitic montmorillonite pl casaturated low-charge cv beidellitic montmorillonite table 11. observed (6 x d060) and calculated (after relationships of radoslovich, 1962 and köster et al., 1999) b unit cell dimensions. sample b observed b – calculated after radoslovich (1962) b – calculated after köster et al. (1999) bu 8.9898 9.0158 8.9377 zg (s) 8.9712 8.9908 8.9433 bd 9.0138 9.0299 8.9693 dr 8.9946 9.0107 8.9523 ši1 8.9898 9.0051 8.9591 ši2 8.9808 8.9990 8.9400 sj 8.9712 8.9900 8.9422 pr 8.9850 8.9952 8.9501 di1 8.9616 8.9937 8.9602 di2 8.9850 8.9908 8.9523 lv 8.9838 8.9981 8.9422 vb 8.9802 8.9926 8.9433 pl 8.9850 8.9929 8.9400 s – broad peak with shoulder g eo lo gi a c ro at ic a geologia croatica 73/148 drits, v.a., besson, g. & muller, f. (1995): an improved model for structural transformations of heat-treated aluminous dioctahedral 2:1 layer silicates.– clay. clay miner., 43, 718–731. doi: 10.1346/ccmn.1995.0430608 držaj, b. & lukacs, e. (1968): nekatere geološke in tehnološke značilnosti ben­ tonitov iz nahajališč v okolici celja [some geological and technological characteristics of bentonites in deposits from celje surroundings – in slovenian].– ge­ ologija, 11, 129–136. emmerich, k., wolters, f., kahr, g. & lagaly, g. (2009): clay profiling: the classification of montmorillonites.– clay. clay miner., 57, 1, 104–114. doi: 10.1346/ccmn.2009.0570110 gates, w.p., slade, p.g., manceau, a. & lanson, b. (2002): site occupan­ cies by iron in nontronites.– clay. clay miner., 50, 223–239. doi: 10.1346/ 000986002760832829 greene-kelly, r. (1953): irreversible dehydration in montmorillonite. part ii.– clay mineral bull, 2, 52–56. greene-kelly, r. (1955): dehydration of the montmorillonite minerals.– mineral. mag., 30, 604–615. doi: 10.1180/minmag.1955.030.228.06 grim, r.e. & kulbicki, g. (1961): montmorillonite: high temperature reactions and classification.– am. mineral., 46, 1329–1369. guggenheim, s., adams, j.m., bain, d.c., bergaya, f., brigatti, m.f., drits., v.a., formoso, m.l.l., galán, e., kogure, t. & stanjek, h. (2006): summary of recommendations of nomenclature committees relevant to clay mineralogy: report of the association internationale pour l’etude des argiles (aipea) nomenclature committee for 2006.– clay miner., 41, 863–877. doi: 10.1180/0009855064140225 heuser, m., andrieux, p., petit, s. & stanjek, h. (2013): iron-bearing smec­ tites: a revised relationship between structural fe, b cell edge lengths and refrac­ tive indices.– clay miner., 48, 97–103. doi: 10.1180/claymin.2013.048.4.06 kaufhold, s., stucki, j.w., finck, n., steininger, r., zimina, a., dohr­ mann, r., ufer, k., pentrák, m. & pentráková, l. (2017): tetrahedral charge and fe content in dioctahedral smectites.– clay miner., 52, 51–65. doi: 10.1180/claymin.2017.052.1.03 komadel, p. & madejová, j. (2010): identification and characterization of inter­ stratified clay minerals with spectroscopic and classical methods.– in: fiore, s, cuadros, j. & huertas, f.j. (eds.): interstratified clay minerals: origin, characterization and geochemical significance. aipea educational series, pub. no. 1., 89–113. köster, h.m. (1993): beschreibung einzelner tonminerale.– in: jasmund, k. & lagaly, g. (eds.): tonminerale und tone: struktur, eigenschaften, anwendun­ gen und einsatz in industrie und umwelt. steinkopff verlag, darmstadt, 33–58. doi: 10.1007/978-3-642-72488-6_2 doi: 10.1180/claymin.1999.034.4.06 köster, h.m., ehrlicher, u., gilg, h.a., jordan, r., murad, e. & on­ nich, k. (1999): mineralogical and chemical characteristics of five nontronites and fe-rich smectites.– clay miner., 34, 579–599. krizmanić, k. (1995): palynology of the miocene bentonite from gornja jelenska (mt. moslavačka gora, croatia).– geol. croat., 48, 147–154. krstić, n., dumurdžanov, n., olujić, j., vujnović, l. & jankovićgolubović, j. (2001): interbedded tuff and bentonite in the neogene lacustrine sediments of the central part of the balkan peninsula. a review.– acta vulcano­ logica, 13, 91–99. krumm, s. (1994): centrifuge, erlangen.– http://www.ccp14.ac.uk/ccp/web-mirrors/ krumm/html/software/winsoft.html lagarec, k. & rancourt, d.g. (1998): recoil mössbauer spectral analysis software for windows.– department of physics, university of ottawa. madejová, j. & komadel, p. (2001): baseline studies of the clay minerals society source clays: infrared methods.– clay. clay miner., 49, 5, 410–432. doi: 10.1346/ ccmn.2001.0490508 mandic, o., de leeuw, a., bulic, j., kuiper, k.f., krijgsman, w. & jurišić-polšak, z. (2012): paleogeographic evolution of the southern pan­ nonian basin: 40ar/39ar age constraints on the miocene continental series of north­ ern croatia.– int. j. earth sci. (geol rundsch), 101, 1033– 1046. doi: 10.1007/ s00531-011-0695-6 marković, s. (2002): hrvatske mineralne sirovine [croatian raw materials – in cro­ atian].– institut za geološka istraživanja, zagreb, 544 p. marković, f., kovačić, m., ćorić, s., tibljaš, d., pezelj, đ., hajek-ta­ desse, v., hernitz-kučenjak, m. & bakrač, k. (2018): miocene tuffs from the north croatian basin.– in: ganić, m., cvetko, v., vulić, p., đurić, d. & đurić, u. (eds.): book of abstracts 17th serbian geological con­ gress, vrnjačka banja, 166–168. meier, l.p., & nüesch, r. (1999): the lower cation exchange capacity limit of montmorillonite.– j. coll. interf. sci., 217, 77–85. doi: 10.1006/jcis.1999.6254 miladinović, d. (1976): bentoniti [bentonites – in bosnian].– in: varićak, d. (ed.): mineralne sirovine bosne i hercegovine, knjiga ii, ležišta nemetala [mineral raw materials of bosnia and hercegovina, book ii, deposits of non-metallic raw materials]. geoinžinjering sarajevo, 402–406. minato, h. (1997): standardization of methods for zeolite speciality determination and techniques for zeolite resources utilization.– in: kirov, g., filizova, l. & petrov, o. (eds.): natural zeolites sofia ‘95, pensoft, sofia, 282–292. moore, d.m. & reynolds jr. r.c. (1997): x-ray diffraction and the identifica­ tion and analysis of clay minerals.– oxford university press, oxford, 378 p. pamić, j. (1997): vulkanske stijene savsko-dravskog međuriječja i baranje (hrvatska) [volcanic rocks from the sava-drava interfluve and baranja in the south pannonian basin (croatia) – in croatian with an english summary].– nafta, zagreb, 192 p. pananalytical (2004): x’pert highscore plus, version 2.1. – almelo. pelayo, m., marco, j.f., fernández, a.m., vergara, l., melón, a.m. & pérez del villar, l. (2018): infrared and mössbauer spectroscopy of fe-rich smectites from morrón de mateo bentonite deposit (spain).– clay miner., 53, 17–28. doi: 10.1180/clm.2018.1 petit, s. (2006): fourier transform infrared spectroscopy.– in: bergaya, f., theng, b.k.g. & lagaly, g. (eds.): dev. clay sci., vol. 1. handbook of clay science, elsevier, amsterdam, 909–918. doi: 10.1016/b978-0-08-098259-5.00009-3 radoslovich, e. (1962): the cell dimensions and symmetry of layer-lattice sili­ cates. ii. regression relations.– am. mineral., 47, 617–636. rihteršič, j. (1958): bentoniti v celjski kotlini [bentonites in celje basin – in slove­ nian].– geologija, 4–13, 193–196. rögl, f. (1998): paleogeographic considerations for mediterranean and paratethys sea­ ways (oligocene to miocene).– ann. naturhist. mus. wien, 99a, 279–310. russell, j.d. & fraser, a.r. (1994): infrared methods.– in: wilson, m.j. (ed.): clay mineralogy: spectroscopic and chemical determinative methods, chapman & hall, london, 11–67. doi: 10.1007/978-94-011-0727-3_2 sato, t., watanabe, t. & otsuka, r. (1992): effects of layer charge, charge lo­ cation, and energy change on expansion properties of dioctahedral smectites.– clay. clay miner., 40, 103–113. doi: 10.1346/ccmn.1992.0400111 schultz, l.g. (1969): lithium and potassium absorption, dehydroxylation tempera­ ture and structural water content of aluminous smectites.– clay. clay miner., 17, 115–149. doi: 10.1346/ccmn.1969.0170302 šegvić, b., toševski, a, števanić, d., biševac, v. & lugović, b. (2006): altered tephra layers in the upper jurassic lemeš deposits near maovice (dalmatia, croatia): clay mineralogy and basic soil mechanic properties.– in: vlahović, i., tibljaš, d., durn, g. & biševac, v. (eds.): 3rd mid-euro­ pean clay conference (mecc 06), abstracts book. faculty of science & faculty of mining, geology and petroleum engineering, zagreb, 104–104. simić v. (2001): bentoniti i bentonitske gline srbije – stanje i perspektiva [bentonites and bentonitic clays of serbia – actual state and prospects – in serbian with an english abstract].– zbornik radova iii međunarodnog savetovanja o površinskoj ekspolataciji glina, ruma, 186–191. simić, v., životić, d., andrić, n., radosavljević-mihajlović, a. & kašić, v. (2014): zeolite deposits and occurrences in serbia – an overview.– in: zeolite 2014, 9th international conference on the occurrence, properties and utilization of natural zeolites, belgrade, serbia, 217–218. środoń, j. (1980): precise identification of illite/smectite interstratifications by x-ray powder diffraction.– clay. clay miner., 28, 401–411. starkey, h.c., blackmon, p.d. & hauff, p.l. (1984): the routine mineralogical analysis of clay-bearing samples.– u.s. geol. surv. bull., 1563, washington, 32 p. stevens, r.e. (1946) a system for calculating analyses of micas and related minerals to end members.– contributions to geochemistry, 1942-45. geol. surv. bull., 950, 101–119. tibljaš, d. (1996): zeoliti i drugi produkti alteracijskih procesa u oligocenskim i donjomiocenskim piroklastitima na širem području macelja [zeolites and the other products of the alteration processes in oligocene and early miocene pyroclastic rocks from the macelj area – in croatian, with an english summary].– unpl. phd thesis, faculty of science, university of zagreb, 167 p. trubelja, f. & barić, lj. (1979): minerali bosne i hercegovine [minerals of bosnia and herzegovina – in croatian, with an english summary].– zemaljski muzej bih, sarajevo, 236–245. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography,main events and depositional dy­ namics.– palaeogeogr. palaeocl., 220, 333–360. doi: 10.1016/j.palaeo.2005.01.011 vujnović, l. (1981): osnovna geološka karta sfrj 1:100000. tumač za list bugojno l33−143 [basic geological map of sfry 1:100000, geology of the bugojno sheet – in bosnian, with an english summary].– savezni geološki zavod, beograd, 58 p. vukanović, m., dimitrijević, n., dimitrijević, m.n., karajičić, lj. & rakić, m.o. (1977): osnovna geološka karta sfrj 1:100000. tumač za list vranje l34−54 [basic geological map of sfry 1:100000, geology of the vranje sheet – in serbian, with an english summary].– savezni geološki zavod, beograd, 53 p. winchester, j.a. & floyd, p.a. (1977): geochemical discrimination of different magma series and their differentiation products using immobile elements.– chem. geol., 20, 325–343. doi: 10.1016/0009-2541(77)90057-2 wolters, f. & emmerich, k. (2007): thermal reactions of smectites – relation of dehydroxylation temperature to octahedral structure.– thermochim. acta, 462, 80–88. doi: 10.1016/j.tca.2007.06.002 2021 | 74/2 | 127–137 | 10 figs. | 3 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction pleistocene deposits may be found on many islands along the eastern adriatic coast in the form of a thin, patch-like cover overlying mesozoic and palaeogene carbonate rocks. they are represented by various types of sediments including breccia, gravel, sand, loess-like sediment and sandy silt, deposited in subaqueous and subaerial environments (bognar et al., 1992; marjanac & marjanac, 2004; lužar oberiter, 2006; pavelić et al., 2006; pavelić et al., 2011; babić et al., 2013, pavelić et al., 2014). these deposits usually overlie small areas of insular karst dolines or they form vertical outcrops along the shoreline where their thickness rarely exceeds 10 m. these various types of sediments are characterized by two main types of the sedimentary record of pleistocene aeolian – alluvial deposits on vrgada island (eastern adriatic coast, croatia) adriano banak1*, kristina pikelj2, borna lužar – oberiter2 and branko kordić1 1 croatian geological survey, department for geology, sachsova 2, hr-10000 zagreb, croatia; (*corresponding author: abanak@hgi-cgs.hr tel.: +385 1 6160 708; fax: +385 1 6160 799) 2 university of zagreb, faculty of science, department of geology, horvatovac 102, hr-10000 zagreb, croatia doi: 10.4154/gc.2021.14 abstract vrgada island is situated in the central part of the eastern adriatic coast. upper cretaceous limestones crop out on the surface and pleistocene sediments cover them in some parts of the island. this study focused on a coastal cliff trending n – s on the northern part of the island. aeolian-alluvial deposits, which are 12.5 m thick were analysed and three different facies in this succession described. the lowermost facies a highlights a strong aeolian influence marked by an increased silt percentage and was deposited during colder climate conditions. sand and gravel in facies b were deposited by streams of dense, cold water formed by melting snow and ice from the nearby dinaric mountains. the bioturbated sandy facies c was probably formed during a warmer climate. an unusually high percentage of augite in the lowermost part of facies a can be explained by the input of volcanic dust, most likely from the roman or campanian volcanoes in italy. this, combined with the surface textures on quartz grains detected from sem photographs indicates a short distance transport for the sediment, no matter which mechanism was dominant. the sediments from vrgada island represent a transitional zone between the north adriatic islands, where aeolian sediments dominate and the south eastern adriatic archipelago, where mixed alluvial and aeolian sediments were observed. deposition: aeolian and alluvial (pavelić et al., 2011, 2014; babić et al., 2013). aeolian sediments were deposited during glacial or stadial dry climate intervals, while alluvial sediments were deposited during interglacial or interstadial warmer and wet climate conditions, indicating that their deposition was climate-driven (kovačić et al., 2018). aeolian and alluvial deposits repeat along the successions on some islands, but they also appear separately on others (bognar et al., 1992; pavelić et al., 2011; babić et al., 2013). pleistocene sediments formed by complex, dual depositional mechanisms also appear to crop out on vrgada island (fig. 1) in the form of coastal cliffs. the main goal of this study is to present a thorough analysis of the sedimentary charaarticle history: manuscript received september 23, 2020 revised manuscript accepted april 23, 2021 available online june 30, 2021 keywords: pleistocene, aeolian, alluvial, facies analysis, adriatic sea, coastal cliff figure 1. location map showing the position of vrgada island and the investigated cliff on the northern part of the island, marked with a yellow arrow. g eo lo gi a c ro at ic a geologia croatica 74/2128 cteristics of these pleistocene sediments and define the sedimentary mechanisms that shaped them. in addition, we compare the sediments of vrgada island with similar deposits described from other islands situated along the eastern adriatic coast. aeolian, silt-sized deposits are the dominant type of pleistocene sediment in the northern part of the eastern adriatic (cremaschi, 1990b; mikulčić pavlaković et al., 2011; wacha et al., 2011a). loess-like sediment intercalated with sand is widespread and well described, especially on susak island where the sediment thickness exceeds 50 m (mikulčić pavlaković et al., 2011; wacha et al., 2011a). together with the padane area in northern italy, this northern part of the eastern adriatic coast formed a large ‘‘loess basin’’ during the last glacial maximum (lgm), when global sea level was -135 m relative to the present sea level (cremaschi, 1990a; 1990b; peltier et al., 2006; clark et al., 2009). most authors concluded that the lgm sea level in the mediterranean was 120±5 m lower than at present (lambeck & bard, 2000; surić et al., 2005). this sea level drop exposed a vast, flat area of the northern adriatic, which enabled the deflation of alluvial plain deposits of the northern adriatic shelf. the source area of material for this large alluvial plain was in the alps and apennines and sediments were transported by the paleo river po. contrary to the northern part of the eastern adriatic coast, its southern part which includes the islands of hvar, vis, lopud, mljet and lastovo displays sand and gravel as the dominant types of pleistocene sediment, in the form of dune sands, sand sheets and gravel-sand filled channels (babić et al., 2013; kovačić et al., 2018). this group of islands is referred to as the south-eastern adriatic (sea) archipelago where aeolian sands were deposited in karst depressions, with the most complete sedimentary records occurring in the central parts of larger depressions (babić et al., 2013). lopud island is an exception, where the thickest sand and gravel deposits are located at the shoreline (kovačić et al., 2018). the main source area for the sea archipelago was the dinarides and material was redeposited by strong southerly winds, so it is fundamentally different from the loess province of the northern adriatic (babić et al., 2013; kovačić et al., 2018). vrgada island is situated in the central part of the eastern adriatic coast (fig. 1), between the northern adriatic islands and the sea archipelago. this makes it an interesting case study, as it represents a transitional zone in the sense of geography and sediment source area. this is why the alluvial aeolian cliff deposits of vrgada island have been chosen for detailed study in order to improve the understanding of the depositional mechanisms and paleo-climate conditions during the pleistocene in the central part of the eastern adriatic coast. 2. geological setting vrgada island is located in the middle part of the croatian coast (northern dalmatia), along the eastern part of the adriatic sea and it is a part of the dinaric mountain range (fig. 1). like the wider surroundings, vrgada island is composed of cenomanian to santonian shallow-water limestones (fig. 2; mamužić & nedela-devidé, 1968; mamužić, 1982), deposited in carbonate platform environments formed on the adria microplate, (detailed information is given in gušić & jelaska, 1993; vlahović et al., 2002; 2005; korbar, 2009 and references therein). accordingly, most of the coast of vrgada island is a steep and rocky carbonate coast, typical of the eastern adriatic (pikelj & juračić, 2013). however, in several places (including the small artina island) pleistocene clastic rocks crop out (figs. 2 and 3). in this study, we focused on a n-s oriented coastal cliff, where the best outcrops are observed (figs. 2 and 3). the total thickness of the outcrop is 12.5 m, and its width is approximately 80 m (fig. 3). the bottom of the outcrop is at 0.5 m a.s.l. and the top is at 13 m a.s.l. an up to 8 m wide sandy beach is developed in front of the studied part of the cliff (fig. 3), as well as on its less steep e-w oriented part. beach sediment is mostly reworked cliff material, subsequently distributed by longshore drift (pikelj & furčić, 2020). the entire cliff top is vegetated with pine trees. 3. methods 3.1. field research initial fieldwork took place in early june 2016, when the cliff was sampled every 25 cm for grain-size analysis and every 2 m for carbonate content, sem and heavy mineral content. a total of 49 sediment samples were taken for various analyses. the entire succession is covered by 1 m of modern soil (fig. 3., on top of section b) and the lowest part of the sediment overfigure 2. geological map of vrgada island and the surrounding area of northern dalmatia: k1lower cretaceous limestones and dolomites; k2upper cretaceous carbonate clastics, scaglia limestones and rudist limestones; pc, e-palaeocene and eocene carbonate turbidites (flysch); liburnia deposits, foraminiferal limestones and transitional deposits; e2,3eocene flysch; e, ol-eocene-oligocene promina beds and carbonate breccias; q1-pleistocene fluvial and fluvioglacial deposits; q2holocene alluvial, lake and pond deposits; aeolian sands, terra rossa. studied pleistocene cliff sediments are marked by red oval (right picture). sediments positioned in the north-west oriented bay are also pleistocene (thick, black line), but their thickness is considerably less. g eologia c roatica banak et al.: the sedimentary record of pleistocene aeolian – alluvial deposits on vrgada island (eastern adriatic coast, croatia) 129 lies carbonate bedrock – upper cretaceous, rudist bearing limestones (fig 3., section a). the investigated deposits are composed of sand, gravel, silt, and carbonate crusts, and form three, lithologically heterogeneous units in vertical succession (fig. 3). 3.2. grain size analysis grain size analysis was carried out on 49 samples in the laboratory of the croatian geological survey by the combined method of wet sieving (for particles > 63 µm) using astm standard stainless sieves and the pipette method (for particles < 63 µm). grain size parameters (mean-mz, median-md, sorting-so, skewness-sk and kurtosis-kg) were calculated using the gradistat statistic package (blott & pye, 2001) according to the original folk & ward (1957) logarithmic graphical measures. in order to characterize the hydrodynamic conditions during sediment deposition, results of the grain size analysis were used to create a cm plot proposed by passega (1957). the cm plot is a binary plot of the coarsest one-percentile (c; in microns) plotted against the median grain size (md; in microns) on a log-probability scale. results of the cm diagram are shown as “clouds” corresponding to the various transport and depositional conditions. 3.3. quantitative heavy mineral analysis heavy minerals were separated from 7 sand samples following standard procedures (mange & maurer, 1992) using the 63-125 µm fraction previously treated with 5% hydrochloric acid and tribromomethane (bromoform: density 2.89 g/cm3). the heavy mineral fractions were mounted onto glass slides and approximately 250 transparent heavy mineral grains were identified per sample by ribbon counting under a polarizing microscope. 3.4. carbonate content the carbonate (caco3) content was calculated from the weight difference before and after cold hydrochloric acid (5%) treatment for each of the 7 samples that were also used for heavy mineral and sem analysis. 3.5. sem analysis photographs of quartz grains were taken using a scanning electron microscope (sem) in the laboratory of geochemistry, ina oil company. previously extracted light mineral fractions from 7 sand samples were chosen for scanning electron microscopy. sand grains were coated with a 25 nm thin gold layer and analysed using a scanning electron microscope jeol, model jsm6510lv. more than 200 different grains were photographed, and the best images that show complete quartz grains were selected for further studies. photographs were taken of the quartz grains in order to identify the shapes of the grains and inspect the detailed morphology of the grain surface. microscopy was conducted within a magnification range of x100 – x950. in this study, the classification method and implemented terminology for quartz grain surface textures and shapes are based on studies of mahaney (2002), strand et al. (2003), strand & immonen (2010) and banak et al. (2013). 4. results 4.1. facies analysis the lower part of the outcrop up to the height of 4.8 m is dominated by silt and fine to medium-grained sand with a zone of femn concretions at 1 m, a 30 cm thick sub-horizontal carbonate crust at the height of 3.1 m and a single thin gravel lens (3 cm) at 3.6 m (figs. 4 and 5). this sediment is determined as facies a. most of this facies, up to the height of 4 m (samples vr-49 to vr-33) is characterized by the moderate dominance of silt (approx. 51%) compared to sand (approx. 40%), while gravel was found to make up less than 5% throughout this entire interval. only the uppermost part of the interval (samples vr-32 and vr31) is marked by the dominance of sand (approx. 62%) over silt figure 3. outcrop of alluvial – aeolian sediment at the shoreline on vrgada island in the form of a coastal cliff. sections a and b display the exact sampling locations. note that the outcrop provides the mixed sandy-gravelly material for the approx. 8 m wide beach. figure 4. details from the vertical succession on vrgada island. facies a (samples vr-49 to vr-31) is dominated by silt and fine to medium – grained sand with a horizon of possible volcanic ash in terra rossa and a carbonate crust in the sand. facies b (samples vr-30 to vr-9) is composed of mostly homogeneous sand and at least 13 gravel lenses and/or layers. facies c (samples vr-8 to vr-1) at the top of the section is represented by medium to coarse grained sand which contains a carbonate crust of irregular shape and vertical, tube-like bioturbations; these last mostly abundant in the uppermost part. g eo lo gi a c ro at ic a geologia croatica 74/2130 (approx. 32%). a shift in the sand to silt ratio in this interval strongly affected the percentage of gravel, which dropped to 0%, while the clay percentage slightly increased. gravel lenses are not present in this interval of facies a. this facies, which is dominated by the finer particles of silt and fine to medium sand (table 1), was formed by deposition from suspension that might also have contained some proportion of grains deposited by rolling (fig. 6). in this facies, the sediment is homogeneous and poorly sorted, probably due to the smaller grain size of the particles and the twofold origin of sediment transport. the lowermost sample vr-49, which is the most fine-grained, with the maximum percentage of clay (24%) and up to 54% of silt represents terra rossa (figs. 4 and 5). this is a reddish clayey to silty-clayey soil developed on top of limestones and it is widespread in the mediterranean region (durn et al., 1999). terra rossa is defined as a polygenetic relict soil, formed during the palaeogene, neogene and/ or hot and humid periods of the quaternary (atalay et al., 1997; durn et al., 1999). the high clay percentage recorded at the bottom of this facies is probably a consequence of a redistribution and possible redeposition of the terra rossa on which the silt was deposited. a conspicuous dark coloured layer several centimetres thick, possibly representing a tephra horizon is intercalated within the otherwise red terra rossa horizon (fig. 5c). close inspection in the field and later microscopic observations revealed that the material contains prismatic augite and abundant, sand-sized biotite grains, which are commonly euhedral (fig. 8). facies b consists of overall horizontally stratified sand and gravel horizons, interfingering in the form of channel type lenses (fig. 4 and fig. 5). this is observed from 4.8m up to 10 m (samples vr-30 to vr-9) in the cliff face. the boundary with facies a is neither sharp nor erosional, but rather a gradual transition from fine to medium-grained sand to coarse-grained sand as seen from grain size analysis. the first gravel lenses appear 30 cm from the top of facies a, but they are barely visible and rather figure 5. the different facies recognized during field research and after grain-size analysis. a) overview photograph of the vrgada island outcrop. b) terra rossa at the lowest part of facies a. shovel for a scale is 1.2 m tall. smaller photo shows fe – mn concretions from silty sediment just above the terra rossa. c) dark gray, 5 cm thick layer within terra rossa. d) uppermost facies c and the upper part of facies b. note the tubular bioturbations at the top 1.5 m. e) close up of the middle part of facies b with a 20 cm gravel-sand unit displaying faint cross bedding topped by erosive channelised gravel unit. graphic scale in the upper left corner is 30 cm. f) part of facies b with horizontally stratified sand and gravel horizons. sand displays colour changes between yellowish and reddish varieties. gravel units have sharp lower boundaries, often with channel forms or laterally extended undulatory surfaces. graphic scale in the upper left corner is 30 cm. g eologia c roatica banak et al.: the sedimentary record of pleistocene aeolian – alluvial deposits on vrgada island (eastern adriatic coast, croatia) 131 thin, only 2 to 3 cm. most of the gravel lenses are present from a height of 5.6 m and to the boundary with facies c. mostly homogeneous, medium to coarse-grained, poorly to very poorly sorted sands are dominant in this part of the succession. they are seemingly without any structures and display vertical colour changes and mottling between yellowish and reddish varieties suggestive of pedogenic processes (fig. 5d and f). at least 17 visible, subhorizontal gravel lenses and/or layers displaying channel forms and occasional faint cross-bedding are observed in this facies (fig. 5f). they rarely exceed 10 cm in thickness. most of the lenses do not have continuous extension through the entire outcrop, but wedge out laterally. channel forms are both gravel dominated and complex gravel-sand units occasionally with crude cross bedding (fig. 5e). gravel textures include a clast supported open framework, bimodal grain supported, and matrix supported varieties. the lower boundaries of the gravel units are sharp, often in the form of channels or laterally extended undulatory surfaces. these surfaces appear to have been amplified by soft-sediment deformation where the gravels are depressed into the underlying sand. gravel clasts are 0.5 3 cm in size and dominantly angular, with a smaller percentage of sub-rounded ones. laboratory analysis revealed that the clasts are of carbonate comtable 1. grain size statistics and textural parameters of the studied vrgada cliff sediment. (legend for the sediment type: gms – gravelly muddy sand; ms – muddy sand; (g)ms –slightly gravelly muddy sand; sm – sandy mud; (g)sm – slightly gravelly sandy mud; gm – gravelly mud). note: sample vr-49 is the bottom-most, while vr-1 is the top-most sample. sample gravel (%) sand (%) silt (%) clay (%) sediment type mz (µm) md (µm) so (phi) sk (phi) kg (phi) c (µm) vr-1 14 56 30 0 gms 225.4 353.6 3.052 0.268 0.725 6727 vr-2 12 54 34 0 gms 243.7 250 2.471 0.01 0.656 3776 vr-3 10 60 30 0 gms 164.3 102.8 2.114 -0.463 0.888 3732 vr-4 8 67 25 0 gms 150 96.68 1.891 -0.52 1.192 3668 vr-5 0 50 50 0 ms 103.9 63 1.678 -0.637 0.974 1834 vr-6 5 48 47 0 (g)ms 122.2 73.79 1.925 -0.566 0.843 3482 vr-7 6 78 16 0 gms 134.2 99.48 1.536 -0.519 1.613 3653 vr-8 0 82 18 0 ms 103.6 92.55 1.575 -0.134 3.056 1741 vr-9 18 44 38 0 gms 142.2 109 3.445 -0.136 0.794 7408 vr-10 0 75 16 9 ms 90.1 97.74 2.35 0.131 2.097 1778 vr-11 8 69 23 0 gms 102.6 110.4 2.321 0.025 2.065 3668 vr-12 6 71 23 0 gms 140.5 112.3 2.125 -0.204 1.365 3563 vr-13 3 77 20 0 (g)ms 172.2 142.1 1.968 -0.176 1.165 3176 vr-14 0 77 23 0 ms 131.8 114.4 1.647 -0.17 1.104 1741 vr-15 0 84 16 0 ms 195.6 168.2 1.869 -0.052 1.122 1852 vr-16 0 81 19 0 ms 152.5 138 1.8 -0.085 1.418 1866 vr-17 20 62 18 0 gms 298.1 206.9 2.506 -0.216 0.822 6964 vr-18 0 72 28 0 ms 118.5 118.1 2.094 0.069 1.391 2518 vr-19 0 67 25 8 ms 95.2 104.5 2.245 0.17 1.416 2377 vr-20 8 71 11 0 gms 200.8 173.6 2.468 -0.02 1.182 3668 vr-21 0 80 20 0 ms 178.4 196.4 2.32 0.179 1.258 1887 vr-22 5 71 24 0 (g)ms 168.9 157.5 2.223 -0.026 1.14 3482 vr-23 0 69 31 0 ms 79.3 97.23 1.88 0.229 1.311 2372 vr-24 4 77 19 0 (g)ms 177.5 169 1.936 -0.027 1.15 3364 vr-25 0 73 27 0 ms 112.5 146.7 2.147 0.291 1.183 1414 vr-26 6 70 24 0 gms 165.2 160.8 2.397 0.029 1.224 3563 vr-27 0 72 28 0 ms 103.3 140.9 2.298 0.258 1.294 2518 vr-28 0 76 24 0 ms 113 139.8 2.081 0.237 1.591 1741 vr-29 4 74 22 0 (g)ms 105.7 136.3 0.823 0.309 1.887 3364 vr-30 2 70 20 8 (g)ms 79.8 131.8 2.227 0.556 1.629 2828 vr-31 0 71 29 0 ms 91.9 114.7 1.614 0.33 1.212 1000 vr-32 0 53 35 12 ms 43.8 66.6 2.018 0.501 1.542 707.1 vr-33 0 28 56 16 sm 23.8 33.36 2.221 0.325 0.915 233.3 vr-34 0 30 70 0 sm 41.6 36.64 1.366 -0.195 0.961 420.4 vr-35 0 35 50 15 sm 27.7 44.38 2.206 0.424 1.106 397.8 vr-36 0 44 38 18 sm 26.2 50.87 2.466 0.469 0.99 707.1 vr-37 0 23 77 0 sm 27.2 23.78 1.627 -0.197 0.931 420.4 vr-38 5 45 39 11 (g)ms 55.6 63 2.586 0.084 2.37 3482 vr-39 0 27 73 0 sm 43.3 39.29 1.381 -0.206 1.207 793.9 vr-40 5 41 54 0 (g)sm 77.1 58.17 1.926 -0.408 1.412 287.2 vr-41 6 52 42 0 gms 116.3 81.79 2.419 -0.262 1.119 280.7 vr-42 6 47 47 0 (g)ms 78.5 71.1 2.527 -0.128 1.13 280.7 vr-43 6 43 51 0 gm 71.9 60.39 2.548 -0.194 1.012 280.7 vr-44 5 67 20 8 (g)ms 89.8 92.73 2.523 0.041 1.933 287.2 vr-45 6 38 56 0 gm 78.3 53.55 2.457 -0.321 1.361 280.7 vr-46 3 43 54 0 (g)sm 70.7 54.63 2.172 -0.265 0.952 314.9 vr-47 0 42 58 0 sm 50.1 49.78 1.928 -0.013 1.036 629.8 vr-48 0 52 31 17 ms 35.3 66.16 2.741 0.393 1.052 1682 vr-49 0 18 58 24 sm 18.08 13.98 2.259 0.19 0.775 217.6 g eo lo gi a c ro at ic a geologia croatica 74/2132 position. this sediment can be compared with alluvial non-confined and channel deposits generated from ephemeral streams (flash floods) identified in the sea archipelago (babić et al., 2013, pavelić et al., 2014). the uppermost part of the sediment succession (samples vr-8 to vr-1) consists of a 2.5 m thick interval marked by fine to medium grained sand and gravel which have been largely altered by an array of vertical, tube-like bioturbations and a carbonate crust (fig. 4 and fig. 5). this sediment is defined as facies c. modern soil, which is approx. 1 m thick overlies this facies. the lower part of the facies, between 10 11 metres, is characterized by a branched, carbonate crust of irregular shape. the character of the boundary with facies b is unclear because the primary structures are altered. in the middle of this interval there is only one clearly visible gravel lens which is 5 cm thick. two cycles with decreasing gravel percentage from the top to the bottom (table 1) are detected in facies c. bioturbations in the form of vertical, tubular feature throughout the whole succession, but are most dense in the top 60 – 70 cm of the interval. they are brown coloured and filled with silt sediment. the density of the carbonate crust structures and bioturbations have completely destroyed the original internal structure of the sand, especially in the uppermost and the lowest segment (fig. 5e). changes in colour of the sediment were detected throughout the succession (fig. 5). using the munsell colour chart we distinguished an almost regular change in facies (a), (b) and (c). the colour change ranges from 5yr 5/8 to 7.5yr 5/6. other variations in colour, but not represented in many horizons include 5yr 5/6, 2.5yr 4/8, 2.5yr 3/6 and 7.5yr 4/4 (all are yellowred). the lowermost part of facies (c) is represented by yellowish red coloured sediment, defined as 5yr 5/8 in the munsell colour chart. 4.2. grain – size results results of the grain size analysis and the textural parameters obtained are summarized in table 1. in general, sand and silt dominate in all samples with averages of 58.7% and 34.8%, respectively. the average percentage of gravel is 3.7%, with a higher proportion in samples from the upper part of the succession, showing almost regular cycles of high and low percentages of gravel. the sediment texture shows a gradual decreasing downward trend in the gravel fraction, whereas the clay content exhibits the opposite trend with samples in its lower part containing up to 24% of the clayey fraction. calculated median (md) and mean size (mz) clearly separate the upper part of the outcrop (samples vr-1 to vr-30) as being coarser, with values generally above 100 microns for both parameters. in contrast, samples from the lower part (vr-31 to vr-49) have median and mean sizes below 100 microns (the exception is sample vr-41). accordingly, prevailing sediment types in the upper part are sands (muddy sands; gravelly muddy sands; slightly gravelly muddy sands), while muds (sandy muds, gra velly sandy muds; slightly gravelly sandy muds) prevail in the lower part of the cliff (table 1). the sediment has been characterized to be poorly to very poorly sorted with so ranging mostly between 1.5–3 with an average value of 2.13 (table 1). skewness varies between 0.56 – 0.64 (average of -0.01) indicating both the presence of finer and coarser fractions along the succession. kurtosis ranges widely between 0.65 and 3.06, with the distribution curves being mostly leptokurtic (average around 1.3). the cm plot shows that all samples are distributed in fields corresponding to transport by tractive currents (fig. 6 and fig. 7), forming the “step” between uniform suspension (rs) and rolling (no). the environmental conditions for the upper 30 coarser samples indicated deposition of sediment from both rolling (no) and suspension and rolling (op and pq). these samples have valu es of c > 1mm (falling in fields i, ii and iii; fig. 6), confirming that they contain grains either transported and deposited by rolling or deposited near the sediment source (passega & byramjee, 1969). the rest of the finer samples fell in field vii (fig. 6) indicating that these grains were deposited from suspension that might contain some rolled grains < 1 mm. these sediment samples correspond to fields rs (uniform suspension) and qr (graded suspension) fields on the cm plot. 4.3. heavy mineral assemblages results of the quantitative heavy mineral analysis on 7 samples from the vrgada succession are shown in table 2. the identified transparent heavy mineral species include zircon, tourmaline, rutile, garnet, augite, cr-spinel, titanite, staurolite, and occasionally kyanite and epidote. all the samples contain essentially the same assortment of heavy minerals, however, the proportions of the individual mineral species such as garnet and augite show distinct differences between samples from the upper and lowermost part of the succession (fig. 4 and fig. 8). figure 6. transport mechanisms of the vrgada sediments shown in the passega cm diagram. fields labelled by roman numbers designate fields of various c and m values (e.g. for fields i-ii-iii c> 1000 microns; for field viii m<100 and c<1000 microns). figure 7. depositional environments of the vrgada sediments shown in the passega cm diagram. as for the depositional environment shown in figure 7, cm plot indicates that the vrgada sediments were deposited by surface flow. g eologia c roatica banak et al.: the sedimentary record of pleistocene aeolian – alluvial deposits on vrgada island (eastern adriatic coast, croatia) 133 4.4. caco3 content the carbonate content in the samples varied significantly from 2.5% in the lowermost sample (vr-49) to 72.9% in the uppermost sample (vr-1), giving a mixed character to the studied deposits. the nature of carbonate grains needs to be further investigated in order to determine their source(s). the average caco3 value for facies a is 21.76 %, for facies b is 53.88 % and for facies c is 59.83 %. 4.5. sem analysis of quartz grains all scanned and photographed quartz grains from the vrgada outcrop are sand-sized particles (>63 µm). in all the seven samples, angular grains dominate (fig. 9). their proportion is over 60% of the total number of grains in the samples. around 5% of grains are very angular or sub-angular. rounded and wellrounded grains make up to another 5%. over 70% of the grains in all samples are of low sphericity. on most grains, conchoidal fractures and v-shaped percussion marks were visible. conchoidal fractures were detected in over 50% of the grains in the samples (fig. 9). a small number of grains showed conchoidal fractures that are nearly the size of the length of the longer axis of the grain, while the majority of grains had conchoidal fractures with 1/3 of that dimension. v-shaped percussion marks were visible on only 3 individual grains. the size of these surface micro textures is in the range of 2–5 µm. they are usually clustered on smooth, flat surfaces of grains in groups that consist of 3 to 5 marks. about 10% of all grains display sets of parallel striations. the length of striation marks is on average between 15 and 20 µm and sets consist of 5 to 6 striations on average. upturned plates are observed on more than 10% of grains. 5. discussion sediments from the vrgada outcrop are divided into 3 different facies: a, b and c. grain size analysis of facies a, b as well as the upper part of facies c indicate deposition of sand and gravel by both, rolling (no) and suspension and rolling (op and pq) which is supported by sem analysis of sandy quartz grains (figs. 6, 7 and 9). aeolian transport was dominant in this facies at least in the lower and middle interval, as the mineral assemblage with an increased percentage of augite (table 2; fig. 8) and sem images of quartz grains (fig. 9) suggest. the occurrence of gravel could represent a fluvial channel incised into the sandy silt, a feature encountered at other localities of pleistocene deposits along the adriatic coast (see babić et al., 2013). based on the grain size distribution, sediment from this facies can be compared to sandy loess horizons from susak island (mikulčić pavlaković et al., 2011). the carbonate content of 21.76% is also comparable to that from susak island which is in the range of 14.9% 25% (mikulčić pavlaković et al., 2011). sand from facies b is similar to lopud island (southern-eastern adriatic) structureless sands from unit u3, deposited by traction from sheet flows in an unconfined stream (kovačić et al., 2018). the lack of lamination in sands from facies b could be a consequence of diagenetic processes following deposition (walker et al., 1978), which is possible considering the changes in sediment colour and mottling that are visible throughout this facies. channel type, gravel lenses and gravel-sand units from facies b can be compared with alluvial non-confined and channel deposits generated from ephemeral streams (flash floods) identified in the sea archipelago islands (babić et al., 2013; pavelić et al., 2014; kovačić et al., 2018). gravel-sized clasts within channel type lenses point to a repeated, almost regular increase in water energy (stronger floods) and transport by rolling from locally exposed carbonate highs or the dinaric mountains. the silt sized fraction from facies b is likely deposited from sustable 2. quantitative heavy mineral analysis of 7 selected samples from the vrgada succession. sample heavy fraction 100% other transparent minerals 100% op lf ot zr tu ru gr au sp ti st ky ep un vr-1 60 1 39 9 5 6 53 6 9 5 2 1 2 2 vr-9 72 1 27 11 2 5 59 2 9 4 5 1 2 vr-17 79 1 20 20 4 9 52 3 6 4 1 1 vr-25 58 3 39 27 1 12 39 1 7 6 5 2 vr-33 75 1 24 13 5 8 47 4 6 9 6 1 1 vr-41 58 2 40 11 1 10 28 35 6 3 3 1 2 vr-49 57 3 40 6 1 16 58 5 12 1 1 figure 8. abundant euhedral biotite grains (a) and green augite (b) from the conspicuous several centimetre-thick dark coloured layer within the lowermost terra rossa horizon. g eo lo gi a c ro at ic a geologia croatica 74/2134 pension and weak traction currents in a pond (nemec & steel, 1984; platt & keller, 1992). it is possible that the sand-gravel body from facies b is the result of sediment transport and deposition within dense and cold water (harasimiuk, 1991; gaudin et al., 2006). these cold, dense water flows probably originated from the melting of snow and ice in the dinaric mountains which are located nearby, in the hinterland of vrgada island (marjanac & marjanac, 2004; krklec et al., 2015). these flows could wash out the sediment deposited in flattened areas at the foothills of the dinaric mountains and transport it over relatively short distances to the present-day location of vrgada island. during the upper pleistocene, the area of vrgada island was most likely connected to the mainland, because the sea level fluctuated and it was significantly lower compared to the present day, even during the warmer periods of the pleistocene (lambeck & bard, 2000; figure 9. morphology of grain surfaces on selected quartz grains from the vrgada outcrop. a) overview of sand sized, quartz grains from facies b. angular and subangular grains dominate. b) v-shaped percussion marks on the surface of the quartz grain from facies b. c) conchoidal fracture on the grain from facies a. d) conchoidal fracture on the sub angular grain from facies b. e) parallel striations on a large flat surface and upturned plates at the bottom of the angular grain. f) conchoidal fracture on the right side of the grain from facies a. radial steps are visible at the upper edge. figure 10. facies a, b and c from the vrgada island cliff with a schematic presentation of the different depositional mechanisms. g eologia c roatica banak et al.: the sedimentary record of pleistocene aeolian – alluvial deposits on vrgada island (eastern adriatic coast, croatia) 135 surić et al., 2005). exact dates of flood events are not known, but a recent study from the southern part of velebit mountain 40 km to the south yielded an age of 20.7 ± 2.2 ka to 22.7 ± 2.7 ka bp, for the retreat of glaciers (sarikaya et al., 2020). dating was performed by cosmogenic 36 cl chronology from a moraine complex known as the rujanska kosa. the authors used 20 mm ka−1 erosion corrected ages for carbonate boulders, as the study area is composed of well-karstified carbonate deposits and located in one of the highest precipitation regions of europe. based on their results we can tentatively suggest that the sediment from facies b could have been deposited shortly after the glaciers started to melt and retreat, during the last glacial maximum lgm (sarikaya et al., 2020). based on the shape, relief, roundness (or angularity) and surface micro textures of sand-sized quartz grains, we can conclude the following: grains with sharp edges, angular or sub-angular in shape and with medium to high relief are dominant in all three facies. conchoidal fractures which are present in most of the grains, are the product of glacial processes and aeolian transport of silt and sand. the smaller number of grains exhibiting socalled v-shaped percussion marks on their surfaces resulted from bouncing and collision between grains in the process of saltation during aeolian transport. they can also be the product of the same process in rivers and streams with high water energy (mahaney, 2002). a small number of grains with visible sets of parallel striations suggest glacial abrasion of grains under the pressure of ice (mahaney, 2002). grains from facies a display surface textures typical for aeolian transport, while grains from facies b and facies c display surface textures which point to mixed, alluvial-aeolian transport. the combination of surface textures on the quartz grains from the vrgada outcrop indicates a short transport distance for sediment no matter which mechanism (aeolian or alluvial) was dominant. muddy and gravelly-muddy sands in facies c are strongly altered by numerous bioturbations and carbonate crust; therefore, it was not possible to recognize any original sedimentary structures (fig. 10). as a consequence, the carbonate content is the highest in this part of the succession and grain size analysis displays high median values (table 1 and fig. 4). sorting is poor throughout the facies, regardless of grain-size (table 1). exact processes leading to cementation and the formation of carbonate crusts are not completely determined, however, they partially include the dissolution of calcareous material by pore waters in buried sediments, followed by the precipitation of calcite during compaction (marshall & pirrie, 2013). carbonate crusts or calcretes are soil related phenomena and much of the calcium carbonate derives from dust (dorn, 1998). they typically form when a mineral precipitates and cements sediment around a nucleus, which is often organic, such as a leaf, tooth, root, or fossil (mozley & davis, 2005), but can also be a gravel clast (dorn, 1998). it is very likely that the process of crust forming began with the formation of a thin calcium carbonate coating around the gravel clasts that are present in facies c. thin coatings grow first on clast undersides and over time, coatings become more continuous on the upper and lower sides (dorn, 1998). gradually, pore spaces between the gravel clasts infill with carbonate and when the pores are blocked, a horizon of laminar calcrete precipitates on top of the impermeable soil (dorn, 1998). bioturbations which permeate almost the whole of facies c probably correlate to the most recent holocene age, reflecting increased biological activity near the present-day surface. heavy mineral assemblages provided information regarding the source of the siliciclastic material found in the vrgada sediments. samples from the upper part of the studied section (facies c and upper part of facies b) are strongly dominated by garnet which regularly constitutes more than 50% of the transparent heavy minerals, while zircon, cr-spinel, augite, titanite, tourmaline and rutile each make up roughly 1-10 % (up to 27 %; table 2, fig. 4). the specific carbonate-dominated lithological makeup of the recent eastern adriatic coastlines hides the potential sources of considerable siliciclastic material arriving from the direction of the dinarides to the east. nevertheless, the observed assemblages clearly indicate that the siliciclastic material most likely derived from the erosion of garnet rich eocene sandstones in clastic deposits which stretch along the eastern adriatic coast and islands (fig. 2; majcen & korolija, 1973; pavičić et al., 2000; 2003). considering that these source rocks are not exposed on vrgada island, the material was probably transported to the studied location by combined alluvial and aeolian mechanisms during times when the sea level was considerably lower. the absence of epidote and hornblende indicates that northern italian rivers, including the po, which otherwise supplied most of the quaternary sediments of the northern adriatic sea bottom and some of the northern adriatic islands (pigorini, 1968; mikulčić pavlaković et al., 2011), did not contribute material to the studied part of the eastern adriatic coastal area. this includes the westerly rivers draining the northern apennines which along with garnet also carry substantial amounts of epidote and amphiboles, but also characteristic minerals such as glaucophane (rizzini, 1974). the pyroxene-amphibole dominated albanese province of the southeastern adriatic, which sourced pleistocene sands of the sea archipelago, is also an unlikely source (babić et al., 2013). unlike samples from the upper two facies in the cliff, those from the lowermost facies a of the section contain a conspicuously high percentage of green clinopyroxene (augite), exceeding 50%. the remainder of the heavy mineral fraction is composed of the same assortment of minerals as in other samples. this addition of clinopyroxene can be explained by volcanic input, from the roman or campanian volcanoes in italy (pigorini, 1968; pouclet et al., 1999; horváth, 2001), with the campanian province as the most probable source area (calanchi & dinelli, 2008). this increase in augite occurs in the terra rossa, in the lowermost part of facies a of the studied section. this sediment is characterized by a dominance of silt, where sedimentation rates were probably lower and most of the siliciclastic input can be attributed to aeolian processes. durn et al. (2007) concluded that in some isolated karst terrains, terra rossa may have formed exclusively from the insoluble residue of limestone and dolomite, but most often it comprises a variety of materials, which in terra rossa from the istrian peninsula are middle pleistocene loess, flysch, tephra and reworked bauxites. due to the grain-size, mineral composition and colour of the terra rossa from vrgada island, this proposed model of external material influx can also be applied in our research. the conspicuous, 5 cm thick, dark grey coloured layer encountered within the otherwise red terra rossa horizon is rich in biotite and green augite and may represent a possible tephra horizon. it is likely that volcanic material which settled from an eruption cloud has been partly mixed into the background sediment at the vrgada site by pedogenic processes, and remains concentrated in the possible tephra horizon described above. tephra layers are a common feature of pleistocene deposits along the g eo lo gi a c ro at ic a geologia croatica 74/2136 croatian coast and have been identified at numerous localities (mikulčić pavlaković et al., 2011; babić et al., 2013; kovačić et al., 2018). due to the absence of absolute dating on the potential tephra horizon, the exact age of this material from vrgada island remains unclear. however, based on the presence of idiomorphic green augite in dark grey coloured aeolian silt, the ‘’tephra’’ from vrgada island could be correlated with the youngest, greyish tephra layer dated at 29.1 ka (wacha et al., 2011b) from susak island, which is located approx. 100 km to the north west. this points to an upper pleistocene age, possibly to mis 3 for the sandy silt from facies a. accordingly, and coupled with the la test study of sarikaya et al. (2020) sand and gravel from facies b and facies c are younger, and the age of the sediment is probably mis 2 or lgm. by means of lithology upper pleistocene deposits on the vrgada island are somewhat similar to those of lopud island (kovačić et al., 2018) in the southern part of the adriatic (table 3), because sand is a dominant fraction and the outcrops are located at the shoreline of both of the islands. 6. conclusion this study presents preliminary results and the first description of the pleistocene sediment succession of the coastal cliff situated on the eastern mid-adriatic vrgada island. studied sediments form a vertical, 12.5 m thick succession composed of alluvial sand intercalated with more than 20 channel type gravel lenses deposited on top of silty, aeolian material and containing a potential tephra layer at the very bottom. three different facies were identified and described. lowermost facies a has a strong aeolian influence marked by an increased silt percentage and was deposited on top of terra rossa during colder climate conditions. sand and gravel in facies b were presumably deposited from sheet flows generated by the melting and retreat of nearby glaciers from the dinaric mountains. bioturbated and concretion-rich sandy facies c was probably formed during a warmer climate. results of modal analysis show that garnet rich eocene sandstones from the flysch basins in dalmatia are likely to have been the source area for the siliciclastic material deposited on vrgada island. an unusually high percentage of augite (58%) in the lowermost part of facies a can be explained by volcanic input, from the roman or most likely campanian volcanoes in italy, which was later mixed into the background sediment. the combination of surface textures on quartz grains detected with sem indicates a short transport distance for the sediment, no matter which mechanism (alluvial or aeolian) was dominant. correlation of the possible tephra horizon from vrgada island with tephra layers on other adriatic islands suggests an upper pleistocene age for the sediment of facies a. vrgada island sediments composed of three different facies represent a transitional zone between the north adriatic islands, where aeolian sediments dominate and the sea archipelago where mixture of alluvial and aeolian sediments are observed. the eastern adriatic coast is mostly described as a karstic hard rocky coast; however, results of this study provide new data about the geological structure of its rare segments developed in soft rocks. new insight into the composition and origin of the studied succession will undoubtedly contribute to the understanding of coastal changes and coastal erosion on vrgada island as well as in similar coastal environments along the croatian coast. furthermore, the obtained results will provide valuable information for the production of new geological maps of the republic of croatia, which is currently underway. the results of this research form the basis for future research of similar sediments and the first step will be to date the potential tephra layer. acknowledgement this paper was partially supported by projects no. 181-181-10961093, 195-1951293-2703 and 195-1951293-0237 of the croatian ministry of science, education and sports. hereby we express our thanks to nikola šoić for his assistance in taking samples from the vertical cliff by applying alpine climbing techniques. we are grateful to robert košćal for his assistance in artwork preparation. we thank the reviewers whose advice and corrections helped us to significantly improve the second version of the manuscript. references atalay, i. (1997): red mediterranean soils in some karstic regions of taurus mountains, turkey.– catena, 28/3–4, 247–260. doi: 10.1016/s0341-8162(96)00041-0 babić, lj., zupanić, j., vidović, j., razum, i., lužar-oberiter, b. & crnjaković, m. (2013): preservation of hanging aeolian deposits in insular karst depressions: sediment sources and implications for the pleistocene palaeogeography of the se adriatic archipelago.– aeol. res., 11, 171–189. doi: 10.1016/j. aeolia.2013.06.003 banak, a., pavelić, d., kovačić, m. & mandic, o. (2013): sedimentary characteristic and source of loess in baranja (eastern croatia).– aeol. res., 11, 129–139. doi: 10.1016/j.aeolia.2013.08.002 blott, s.j. & pye, k. (2001): gradstat: a grain size distribution and statistics package for the analysis of unconsolidated sediments. earth surface process.– landforms, 26, 1237–1248. bognar, a., klein, v., mesić, i., culiberg, m., bogunović, m., sarkotić-šlat, m. & horvatinčić, n. (1992): quaternary sands at the south-eastern part of the mljet island.– in: bognar, a. (ed.): proceedings of the international symposium ‘geomorphology and sea’ and the meeting of the geomorphological commission of the carpatho–balkan countries. department of geography, faculty of science, university of zagreb, zagreb, 99–110. calanchi, n. & dinelli, e. (2008): tephrostratigraphy of the last 170 ka in sedimentary successions from the adriatic sea.– j. volc. geoth. res., 177, 81–95. doi: 10.1016/j.jvolgeores.2008.06.008 clark, p.u., dyke, a.s., shakun, j.d., carlson, a.e., clark, j., wohlfahrt, b., mitrovica, j.x., hoestetler, s.w. & mccabe, a.m. (2009): the last glacial maximum.– science, 325, 710–714. doi: 10.1126/science.1172873 cremaschi, m. (1990a): the loess deposits in northern and central italy: a loess basin between the alps and the mediterranean regions.– in: cremaschi, m. (ed.): the loess in northern and central italy. centro di studio per la stratigrafia e petrografia delle alpi centrale. editrice gutenberg, milan, 15–19. cremaschi, m. (1990b): stratigraphy and palaeoenvironmental significance of the loess deposits on susak island (dalmatian archipelago).– quat. int., 5, 97–106. doi: 10.1016/1040-6182(90)90029-4 table 3. comparison of main characteristics of vrgada island deposits with two previously described sedimentary provinces of the eastern adriatic coast. northern adriatic vrgada island sea archipelago dominant deposits sandy loess, loess like sediment silty sand with gravel lenses dune sands, sand sheets main heavy minerals amphibole, epidote, garnet garnet, zircon, augite clinopyroxene, orthopyroxene, amphibole tephra occurance yes possible yes source area alps, apennines dinarides, alps? dinarides g eologia c roatica banak et al.: the sedimentary record of pleistocene aeolian – alluvial deposits on vrgada island (eastern adriatic coast, croatia) 137 dorn, r.i. (1998): rock coatings. developments in earth surface processes 6. elsevier science. amsterdam, netherlands, 429 p. durn, g., ottner, f. & slovenec, d. (1999): mineralogical and geochemical indicators of the polygenetic nature of terra rossa in istria, croatia.– geoderma, 91, 1–2, 125–150. doi: 10.1016/s0016-7061(98)00130-x durn, g., aljinović, d., crnjaković, m. & lugović, b. (2007): chapter 28: heavy and light mineral fractions indicate polygenesis of extensive terra rossa soils in istria, croatia.– dev. in sed., 58, 701–737. folk, r.l. & ward, w. (1957): brazos river bar: a study in the significance of grain size parameters.– j. sed. petro., 27, 3–26. doi: 10.1306/74d70646-2b21-11d78648000102c1865d gaudin, m., serge berné, jouanneau, j.-m., palanques, a., puig, p., mulder, t., cirac, p., rabineau, m. & imbert, p. (2006): massive sand beds attributed to deposition by dense water cascades in the bourcart canyon head, gulf of lions (northwestern mediterranean sea).– mar. geol., 234, 111–128. doi: 10.1016/j.margeo.2006.09.020 gušić, i. & jelaska, v. (1993): upper cenomanian–lower turonian sea-level rise and its consequences on the adriatic–dinaric carbonate platform.– geologische rundschau, 82/4, 676–686. harasimiuk, m. (1991): vistulian glacial cycle of the fluvial processes development in the valley of the middle wieprz river (se poland).– annales umcs, 46, 81–109. horváth, e. (2001): marker horizons in the loesses of the carpathian basin.– quat. int., 76/77, 157–163. doi: 10.1016/s1040-6182(00)00099-9 korbar, t. (2009): orogenic evolution of the external dinarides in the ne adriatic region: a model constrained by tectonostratigraphy of upper cretaceous to paleogene carbonates.– earth. sci. rev., 96/4, 296–312. doi: 10.1016/j.earscirev.2009.07.004 kovačić, m., pavelić, d., vlahović, i., marković, f., wacha, l., kampić, f., rončević, s. & drempetić, d. (2018): pleistocene alluvial and aeolian deposits with tephra on the island of lopud (eastern mid-adriatic, croatia): provenance, wind regime, and climate controls.– quat. int., 494, 92–104. doi: 10.1016/j.quaint.2017.11.054 krklec, k., domíngez-villar, d. & perica, d. (2015): depositional environments and diagenesis of a carbonate till from a quaternary paleo glacier sequence in the southern velebit mountain (croatia).– palaeogeogr. palaeocl. palaeoec., 436, 188–198. doi: 10.1016/j.palaeo.2015.07.004 lambeck, k. & bard, e. (2000): sea-level change along the french mediterranean coast for the past 30 000 years.– earth. plan. sci. lett., 175, 203–222. doi: 10.1016/ s0012-821x(99)00289-7 lužar-oberiter, b. (2006): usporedba sastava i porijekla obalnih pijesaka otoka hvara i raba.– unpublished msc thesis, university of zagreb, 85 p. mahaney, w.c. (2002): atlas of sand grain surface textures and applications.– oxford university press, 237 p. majcen, ž. & korolija, b. (1973): explanatory notes for sheet zadar, basic geological map of yugoslavia, 1:100000.– federal geological institute, belgrade, croatian geological institute, zagreb, 40 p. mamužić, p. & nedela-devidé, d. (1968): basic geological map of sfry: biograd sheet, scale 1: 100.000, k33-7.– inst. geol. istraž., zagreb (1963), sav. geol. zavod beograd. mamužić, p. (1982): basic geological map of sfry: šibenik sheet, scale 1: 100.000, k33-8.inst. geol. istraž., zagreb (1962-1965), sav. geol. zavod beograd. mange, m.a. & maurer, h.f.w. (1992): heavy minerals in colour.– chapman and hall, london, 151 p. doi: 10.1007/978-94-011-2308-2 marjanac, lj. & marjanac, t. (2004): glacial history of croatian adriatic and coastal dinarides.– in: ehlers, j. & gibbard, p.l. (eds.): quaternary glaciations – extent and chronology, elsevier, 19–26. doi: 10.1016/s15710866(04)80053-8 marshall, j.d. & pirrie, d. (2013): carbonate concretions-explained.– geol. today, 29, issue 2, 53–62. doi: 10.1111/gto.12002 mikulčić pavlaković, s., crnjaković, m., tibljaš, d., šoufek, m., wacha, l., frechen, m. & lacković, d. (2011): mineralogical and geochemical characteristics of quaternary sediments from the island of susak (northern adriatic, croatia).– quat. int., 234, 32–49. doi: 10.1016/j.quaint.2010.02.005 mozley, p.s. & davis, j.m. (2005): internal structure and mode of growth of elongate calcite concretions: evidence for small-scale microbially induced, chemical heterogeneity in groundwater.– geol. soc. am. bullett., 117, 1400–1412. doi: 10.1130/b25618.1 nemec, w. & steel, r.j. (1984): alluvial and costal conglomerates: their significant features and some comments on gravelly mass-flow deposits.– in: coster, e.h. & steel, e.h. (eds.): sedimentology of gravels and conglomerates, vol. 5. canadian society of petroleum geologists memoir, 597–604. passega, r. (1957): texture as characteristics of clastic deposition.– am. assoc. petro. geol. bullett., 41, 1952–1984. passega, r. & byramjee, r. (1969): grain-size image of clastic deposits.– sedimentology, 11, 233–252. pavelić, d., kovačić, m. & vlahović, i. (2006): periglacial aeolian–alluvial interaction: pleistocene of the island of hvar (eastern adriatic, croatia).– in: hoyanagi, k., takano, o. & kano, k. (eds.): from the highest to the deepest: abstracts, volume a, 218, isc 2006, fukuoka. pavelić, d., kovačić, m., vlahović, i. & wacha, l. (2011): pleistocene calcareous aeolian-alluvial deposition in a steep relief karstic coastal belt (island of hvar, eastern adriatic, croatia).– sed. geol., 239, 46–79. doi: 10.1016/j.sedgeo.2011.05.005 pavelić, d., kovačić, m., vlahović, i., mandic, o., marković, f. & wacha, l. (2014): topography controlling the wind regime on the karstic coast: late pleistocene coastal calcareous sands of eastern mid-adriatic, croatia.– facies, 60, 843–863. doi: 10.1007/s10347-014-0411-7 pavičić, lj., babić, lj., crnjaković, m., & zupanič, j. (2000): the provenance of sands on north dalmatian beaches: between ignorance and the need for coastal zone management.– period. biolog., 102, 349–354. pavičić, lj., zupanič, j. & babić, lj. (2003): changing heavy mineral associations along the outer dinaric eocene flysch belt: evidence for different structures along the rising dinarides.– in: vlahović, i. (ed.): 22nd ias meeting of sedimentology: abstracts book, p. 149. peltier, w.r. & fairbanks, r.g. (2006): global glacial ice volume and last glacial maximum duration from an extended barbados sea level record.– quat. sci., 25, 3322–3337. doi: 10.1016/j.quascirev.2006.04.010 pigorini, b. (1968): sources and dispersion of recent sediments of the adriatic sea.– marine geol., 6, 187–229. doi: 10.1016/0025-3227(68)90031-5 pikelj, k. & juračić, m. (2013): eastern adriatic coast (eac): geomorphology and coastal vulnerability of a karstic coast.– j. coast. res., 29/4, 944–957. doi: 10.2112/jcoastres-d-12-00136.1 pikelj, k. & furčić, n. (2020): impact of cliff erosion on marine sediment composition indication of local coastline evolution (vrgada island, croatia).– in: bono ra, l. et al. (eds.): proceedings of the eighth international symposium monitoring of mediterranean coastal areas. problems and measurement techniques. livorno, italy, 2020, 462–468. platt, n.h. & keller, b. (1992): distal alluvial deposits in a foreland basin setting – the lower freshwater molasse (lower miocene), switzerland: sedimentology, architecture and paleosols.– sedimentology, 39, 545–565. pouclet, a., horváth, e., gábris, g.y. & juvigné, e. (1999): the bag tephra, a widespread tephrochronological marker in middle europe: chemical and mineralogical investigations.– bullet. volc., 60, 265–272. doi: 10.1007/s004450050275 rizzini, a. (1974): holocene sedimentary cycle and heavy-mineral distribution, romagna-marche coastal plain, italy.– sed. geol., 11, 17–37. doi: 10.1016/00370738(74)90003-7 sarikaya, m.a., stepišnik, u., žebre, m, ciner, a., yildirim, c., vlahović, i., tomljenović, b., matoš, b. & wilcken, k.m. (2020): last glacial maximum deglaciation of the southern velebit mt. (croatia): insights from cosmogenic 36cl dating of rujanska kosa.– med. geosci. rev., 2, 53–64. doi: 10.1007/s42990-020-00030-9 strand, k., passchier, s. & näsi, j. (2003): implications of quartz grain microtextures for onset of eocene/oligocene glaciation in prydz bay, odp site 1166, antarctica.– palaeogeogr. palaeoclim. palaeoec., 198, 101–111. doi: 10.1016/ s0031-0182(03)00396-1 strand, k. & immonen, n. (2010): dynamics of the barents-kara ice sheet as revealed by quartz sand grain microtextures of the late pleistocene arctic ocean sediments.– quat. sci. rev., 29, 3583–3589. doi: 10.1016/j.quascirev.2010.09.017 surić, m., juračić, m., horvatinčić, n. & krajcar bronić, i. (2005): late pleistocene holocene sea-level rise and the pattern of coastal karst inundation records from submerged speleothems along the eastern adriatic coast (croatia).– marine geol., 214, 1/3, 163–175. doi:10.1016/j.margeo.2004.10.030 vlahović, i., tišljar, j., velić, i. & matičec, d. (2002): the karst dinarides are composed of relics of a single mesozoic platform: facts and consequences.– geol. croat., 55/2, 171–183. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeogr. palaeoclim. palaeoec., 220/3–4, 333–360. doi: 10.1016/j.palaeo.2005.01.011 wacha, l., mikulčić pavlaković, s., novothny, á., crnjaković, m. & frechen, m. (2011a): luminescence dating of upper pleistocene loess from the island of susak in croatia.– quat. int., 234, 50–61. doi: 10.1016/j. quaint.2009.12.017 wacha, l., mikulčić pavlaković, s., frechen, m. & crnjaković, m. (2011b): the loess chronology of the island of susak, croatia.– eiszeitalter und gegenwart e quat. sci. j., 60, 153–169. doi: 10.3285/eg.60.1.11 walker, t.r.,waugh, b. & grone, a.j. (1978): diagenesis in first-cycle desert alluvium of cenozoic age, southwestern united states and northwestern mexico.– geol. soc. am. bulletin, 89, 19–32. doi: 10.1130/0016-7606(1978)89<19:difdao>2.0.co;2 2019 | 72 / special issue | 3–17 | 19 figs. | 1 tab. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society article history: manuscript received april 23, 2019 revised manuscript accepted september 06, 2019 available online december 20, 2019 keywords: arcgis, petrel, sequential indicator simulation, quaternary, 3d geological modeling 1. introduction beijing is a city built on quaternary sediments. therefore, its urban geological exploration, sustainable energy development and mining are closely related to unconsolidated quaternary sediments. therefore an understanding of these quaternary sediments and their three-dimensional geological structure in beijing are urgently needed. international researchers (velić & durn, 1993; velić et al., 1999; terhorst et al., 2013; antoine et al., 2013; brkić, 2017; grizelj et al., 2017; lehmkuhl et al., 2018) are currently conducting research on quaternary sediments, while the study of these sediments in beijing by chinese scientists has a history of more than 100 years. there have been numerous scientific findings regarding quaternary palaeoclimate change (zhao et al., 1984; wei et al., 1997; yao et al., 2007; zhao et al., 2008), animal and plant development and evolution (zhou et al., 1987; kong et al., 1980; shan et al., 1994), palaeogeographic environmental evolution (zhang et al., 1981; hao et al., 2002; yuan et al., 2002; luan et al., 2008) and quaternary stratigraphic division (li et al., 1979; li & chen, 1992, 1994; guo et al., 2008). this paper focuses on the threedimensional structure of the quaternary system in the beijing plain (cao et al., 2004; pan et al., 2006; cai et al., 2009a, 2009b; zhu et al., 2012; shen et al., 2015). however, it should be emphasized that previous modeling works were all based on sufficient drilling, logging, geophysical and geochemical data, which requires the cooperation of multiple departments. furthermore, economic and time costs are expensive. at present, researchers can obtain very little drilling information at the beginning of the study. due to this paucity of drilling information, the three-dimensional modeling of underground structures is difficult to complete and researchers are unable to conduct in-depth research on urban disaster prevention and mitigation. integrated 3d modeling of quaternary sediments in the beijing plain, based on a sequential indicator simulation ai xiao1, sun baitao2 and chen xiangzhao1 1 institute of engineering mechanics, china earthquake administration, key laboratory of earthquake engineering and engineering vibration, china earthquake administration; (axz.1988@163.com) 2 institute of engineering mechanics, china earthquake administration, key laboratory of earthquake engineering and engineering vibration, china earthquake administration; (corresponding author: sunbt@iem.cn) doi: 10.4154/gc.2019.28 abstract the study of quaternary sediments has long been a focus for geologists, primarily because they are closely aligned with urban safety assessment, energy exploitation and sustainable development. the beijing plain was selected for this study. using existing drilling data and knowledge of the sedimentary characteristics in this study area, a geological model was developed with petrel software using the sequential indicator simulation algorithm. the main aims were firstly, to integrate arcgis and petrel with drilling information, a digital elevation model, a stratum sedimentary thickness plan and other multi-platform data on the same platform. secondly, establish a lithology variogram model and then construct a quaternary lithology model based on the variogram model and finally, use the established lithology model to preliminarily analyze the lateral and vertical distribution rules of quaternary lithology in the study area. these results provide new methods for the establishment of geologic modeling during the preliminary stages when studying engineering geology. the results will also provide baseline information for later research. with the maturity of the commercial software for three-dimensional modeling, sequential instruction simulation technology is a new modeling technology which can solve the above problems. this technology can not only reproduce the underground geological properties, but also contextualize the known well data (wang, 2017; zhou, 2017; yuan et al., 2017; liu & zhou, 2018). it can also obtain multiple three-dimensional models with equal probability to satisfy the description and analy sis of underground uncertainty. at present, the mainstream geological modeling software represented by the petrel software has been widely used in modeling work during the early stages of exploration (wang et al., 2014; li & wei, 2015; song et al., 2016). in this study, sequential instruction simulation technology will conduct three-dimensional modeling of quaternary systems in the beijing plain. this study aims to provide new thinking and methods for geological modeling in the early stages of urban safety assessments, and to provide theoretical support and baseline information for future urban geological research in beijing. 2. geological setting beijing geotectonics are located in the western part of the yanshan subsidence zone, which is the central part of the north china platform. during its long geological history, beijing has experienced a great subsidence and violent orogeny. the tectonic activity was dominated by the yanshanian movement in the mesozoic which finally laid the foundation framework of the geological structure and the embryonic geomorphological development in beijing (huo, 1989). when combined with the influence of the himalayan movements since the cretaceous, the geological history and geomorphological types of beijing have become more complex and diverse. until the middle and late quaternary, beijing’s landforms were being shaped. beijing is a city with high mountains in the northwest and low plains in the southeast. sediments are mostly transported from the mountainous areas to the plains (bug eo lo gi a c ro at ic a geologia croatica 72 / special issue4 reau of geology and mineral resources of beijing municipality, 1991). the quaternary system in the beijing plain is generally composed of several huge river fans and depressions. the bedrock burial depth in the beijing plain varies greatly and is cut by several faults, forming the famous beijing fault basin (fig. 1). here, the study area is located in the middle and lower areas of beijing (fig. 2), comprising a total area of approximately 5600 km2. this includes the main urban area of beijing and the northern changping district, the shunyi district and the tongzhou district. it also incorporates some areas around the main urban area of beijing, such as the yanqing, miyun, fangshan districts and so on. this geological modeling study focuses on samples from 832 drill holes provided by the beijing earthquake agency. the drilling locations cover the entire study area, with the distribution concentrated in the urban area of beijing (within the fourth ring). there is a small number outside the urban area (fig. 3). 3. technical routes the key components of this modeling study consist of three sections: 1) processing and loading the drilling data, 2) constructing the model’s framework and 3) conducting the geological modeling (fig. 4). we divided the construction of the model’s framework into three steps: 1) the establishment of the model’s top and base, 2) the model’s quality control and 3) the construction of its horizontal and vertical grid. in order to show the real landscape of the study area, the modeling process of its top and base was different to a traditional software workflow. after building the framework, we completed the geological modeling of the study area by setting reasonable parameters for the sequential indicator simulation. 4. sequential indicator simulation 4.1. variogram a variogram is the core concept in geostatistics. its accuracy is directly related to the accuracy of the sequential indicator simulation results. in view of this, we firstly introduce the concept of the variogram before explaining the principle of sequential indicator simulation. the variogram is a method used to describe the space variation of the underground geological property, and the spatial corfigure 1. sketch map of geological structures in beijing plain (modified from cai et al., 2016). figure 2. location of the study area. g eologia c roatica xiao et al.: integrated 3d modeling of quaternary sediments in the beijing plain, based on a sequential indicator simulation 5 relation of regionalized variables can be described quantitatively (clayton & andre, 1998). its principle is that the correlation between close samples in space is strong, while the correlation between distant samples is weak. when the distance between samples exceeds a minimum correlation (range), the influence of distance is small (fig. 5). petrel provides three variogram models, which are exponential, spherical and gaussian (fig. 6). in practice, not all combinations of the variogram are as typical as the theoretical models. figure 6. demonstrates that among the three kinds of theoretical models, the exponential model shows the most significant change in data correlation within the range, the gauss model shows the least change in data correlation, and the spherical model shows a moderate change in data correlation. due to the anisotropy of geological bodies, the variogram calculations must be from three different directions, the main direction, the secondary figure 3. drilling locations in the study area. figure 4. the conceptual framework for the modeling process. figure 5. a classic variogram model. figure 6. three types of variogram models. g eo lo gi a c ro at ic a geologia croatica 72 / special issue6 direction and the vertical direction. the main direction represents the maximum correlation between data points in this direction, the secondary direction is the direction perpendicular to the main direction and the vertical direction is the direction perpendicular to the plane formed by both the main and the secondary directions. 4.2. the principle of sequential indicator simulation and its implementation the principle of sequential indicator simulation can be explained as follows (feng et al., 2001): assume that {z(x), x∈a} is a random function corresponding to regional variables, wherein a represents a region. for a threshold z0 of regionalized variables, a two-dimensional indicator random variable i (x; z 0) is defined as: i x z z x z z x z ( ; ) ( ) ( ) 0 0 0 1 0 = £ > ì í î if the random function z(x) has a set of observations {z(xα), α∈(n)}, then the conditional probability distribution of z(x) based on the set of observations is equal to the conditional expectation of i(x; z0): e{i (x; z0) | z(xα) α∈(n)}=p{z (x) ≤ z0| z(xα), α∈(n)} then the conditional probability p{z(x)≤z0 i(x; z0) | z(xα),α∈(n)} can be estimated by the estimates of the indicative conditional expectations e{i;x z0) | z(xα), α∈(n)}. according to the kriging method, the kriging estimate is the conditional cumulative probability of the point, which is expressed as follows: f(x; z0 | z(xα), α∈(n) = p{z(x)≤z0 | z(xα), α∈(n) }= n 1= ∑ a a l (x; z0) i (xα; z0) among these, i (xα; z0) represents the indicative value of the sample point at the threshold z0, and λα(x;z0) represents the corresponding indicator kriging weight, which is determined by the following kriging equations: ( ) ( ) ( ) ( ) ( ) n 0 i 0 0 i 0 1 n 0 1 x ;z c x x ;z x;z c x x ;z 1 , 2,3, , x ;z 1 n = =  − + = − = …    =  ∑ ∑ b a a b b lb m a lb in the formula, ci (x; z0) is a covariance function. it can be seen that ci (xβ-xα; z0) represents the covariance function between all known points, and ci (x-xα; z0) represents the covariance function between the selected unknown points and all known points, while (x; z0) is a lagrange multiplier. this means that k thresholds need such kriging equations, and the covariance function of each kriging equation is different, so the actual calculation process is very complex. in summary, under given k thresholds, each threshold corresponds to a kriging equation for any point to be evaluated. the figure 7. 3d visualization of the drill holes in the study area. g eologia c roatica xiao et al.: integrated 3d modeling of quaternary sediments in the beijing plain, based on a sequential indicator simulation 7 corresponding probabilities under each threshold can be obtained by solving the equations. then all the probabilities belonging to each threshold are normalized to determine the conditional distribution probability function at the point to be estimated and a concrete implementation of the point to be estimated can be obtained. when the random variable z (x) is a discrete variable (such as sedimentary facies), the formula is simpler. the number of k thresholds corresponds to the k type of the random variable z (x). assuming that there are three lithologies in the study area and their corresponding numbers are 1, 2 and 3, the corresponding threshold is the number of these three lithologies. it can change the formula of the indicator variable to the following formula: i x z z x ( ; ) ( ) 0 1 0 = îì í î type k else in summary, the implementation steps of sequential instruction simulation are as follows: (1) divide variables into k thresholds. (2) calculate the variation function of each indicator variable. (3) simulate the estimated point. a. define conditional data within the search scope. b. for any k = 1, 2,..., k, which represents the corresponding threshold, establish the ordinary kriging equations based on the indicator covariance model of the threshold. then solve the kriging equations and calculate the probability that the sample points belong to the corresponding threshold. c. normalize all the probability belonging to each threshold, and then determine the conditional distribution probability function at the point to be evaluated and its concrete implementation can be obtained. d. add the point to the original data. (4) repeat step (3) until all unknown points are simulated. figure 8. the framework of the model; a) the top surface of the model, b) the bottom surface of the model. a b g eo lo gi a c ro at ic a geologia croatica 72 / special issue8 5. geological modeling 5.1. data loading drilling data provided by the beijing earthquake agency (832 drills), was pre-processed and completed according to the loading format of the petrel software and the well head data template, stratigraphic data template and lithological data template. then, the drilling data in the study area were uploaded into the software. the well head data was the basic data for the study area, and included four basic data, which were the well name, well coordinates, well elevation and well depth. as the drills used in this study are all safety evaluation drills, the true vertical depth (tvd) of all drills used in this research ranges from 50 to 350 metres (only through quaternary sediments). stratigraphic data is the basic data to build the top and basal framework of the model. among these, the top data of the framework is the real elevation of each drill hole in the study area, and the basal data of the framework is the bottom depth of the quaternary strata. lithological data are the lithological information for each drilling hole, which needs to be loaded as the format of the well log. according to the sequence of well head data, stratigraphic data and lithological data, the database establishment in the early stage of modeling was completed (fig. 7). 5.2. construction of the model framework for this study, the drilling data were mainly used for safety evaluation. unlike petroleum geological exploration, they generally do not have a seismic interpretation horizon. therefore, how to determine a realistic top and base of the research area without adequate drilling was a key problem. the solutions, following (zhao & liu, 2007) were as follows: (1) download the beijing digital elevation model (dem) from the geospatial data cloud and use the mosaic tool in arcgis to mosaic and tailor the data. (2) convert the processed data into point files with corresponding elevation information and convert point files into data formats supported by the petrel software using the data interoperability tool in arcgis. (3) perform the interpolation operation of point files and conduct quality control using stratigraphic data. after interpolation, assign corresponding colours to different heights to reflect the real landforms of the study area. (4) clip the surface file formed in step (3) by using the boundary of the study area, to obtain the top surface of the model (fig. 8a). (5) obtain the quaternary sedimentary thickness contour map of the study area by reviewing the relevant literature (cai et al., 2009a, 2009b). vectorize and convert the thickness contour map into a point file with thickness information using arcgis (fig. 9). (6) convert point files into data formats supported by petrel software using the data interoperability tool in arcgis, then interpolate the point files into a thickness surface using petrel. (7) perform the subtraction operation on the top and thickness surfaces using petrel to form the basal surface of the model (fig. 8b). in summary, this method will retain the geomorphological characteristics of beijing to the greatest extent and reflect the real surface and underground information of the study area. when the establishment of the top and bottom of the model was finalized, the horizontal and vertical grids were built based on these surfaces. four vertical grid building methods are provided in petrel: according to the trend of the top surface of the model (fig. 10a); according to the trend of the bottom surface of the model (fig. 10b); according to the proportion of manual settings (fig. 10c); and according to the number of vertical layers by the equal proportion (fig. 10d). there is no precise seismic data in this study, so the distribution law of underground strata in the study area is not known. for this reason, the fourth method is chosen in this model. after testing, setting the number of vertical layers to 400 can achieve higher accuracy. finally, the adjustment of relevant parameters of the geological modeling was conducted. figure 9. thickness distribution of the quaternary strata. g eologia c roatica xiao et al.: integrated 3d modeling of quaternary sediments in the beijing plain, based on a sequential indicator simulation 9 5.3. computation of the variogram after the model framework has been established, we simulated the main lithology of the study area. due to the confidentiality of relevant data, only five main lithologies were selected in this study area, each lithologic code and its percentage content is shown in table 1. the anthropogenic layer (backfill) is widely distributed over the surface of the study area after the extensive human development and transformation in beijing. therefore, the overall distribution of backfill does not conform to the sedimentary law of the study area. in order to reflect the true three-dimensional structure of quaternary sediments, backfill was not added to lithological modeling in this study. the selection of the major direction in the variogram is the most important part in the whole process. the main direction represents the direction with the best correlation among the sample points, which has the largest range. the scale of variation not only reflects the change of regional variables in a certain direction, but also reflects the average scale of the carrier of regional variables (such as lithology in the model) in a certain direction. therefore, in order to realize the analysis of the underground three-dimensional structure in the study area, the range can be used to predict the extension size of lithology in a particular direction. li et al. (1999) argued that before stochastic simulation, the spatial structure of sedimentary facies should be considered comprehensively to determine the ellipse size used to search the simulated grid points and conditional data around a grid node. in figure 10. four vertical grid building methods; a) follow top, b) follow base, c) manual settings, d) equal proportion. figure 11. sketch map showing quaternary geological units and their combination in the beijing plain (modified from cai et al., 2009a). figure 12. isopach map of pebble deposits. g eo lo gi a c ro at ic a geologia croatica 72 / special issue10 addition, the number of simulated grid points and conditional data needed to simulate a grid point should also be considered comprehensively. based on this theory, duan et al. (2007) holds that in practice, two methods can be used to determine the major direction and verify each other. one is to refer to the sedimentary facies map and the other is to examine the contour line or trend surface map of certain attributes. the cenozoic of beijing inherited the tectonic framework of the late mesozoic. from the end of the cretaceous to the pliocene, there was a very large ancient lake (fault basin) in the beijing plain, which (the beijing ancient lake). the lake surface expanded and the lake water became deeper during the neogene. during the pliocene, the rise of the xishan mountain accelerated, the ancient lake of yanqing formed and the water surface gradually expanded. the ancient yongding river was eroded by fissures along the axis of the youzhou anticline. when the water level of the ancient lake in yanqing was high, the fissures along the axis of the youzhou anticline were connected with the ancient yongding table 1. variogram parameters of lithology in the study area. codes lithology percentage（%） major range（m） minor range（m） vertical range（m） major direction（o） 1 pebble 25.1 13911 11845 30 287 2 silty clay 25.8 10528 9049 23 307 3 sand 13.0 5819 4950 15 320 4 clayey & sandy silt 11.0 5917 3582 11 323 5 other lithology 22.8 10872 7185 21 303 figure 13. variogram models of each lithology in the study area; a) variogram model of other lithology in the major direction, b) variogram model of other lithology in the minor direction. a b g eologia c roatica xiao et al.: integrated 3d modeling of quaternary sediments in the beijing plain, based on a sequential indicator simulation 11 figure 13. continued. c) variogram model of pebbles in the major direction, d) variogram model of pebbles in the minor direction, e) variogram model of silty clay in the major direction. c d e g eo lo gi a c ro at ic a geologia croatica 72 / special issue12 figure 13. continued. f) variogram model of silty clay in the minor direction, g) variogram model of fine sand in the major direction, h) variogram model of fine sand in the minor direction f g h g eologia c roatica xiao et al.: integrated 3d modeling of quaternary sediments in the beijing plain, based on a sequential indicator simulation 13 river to form pulsating floods, and more than ten layers of diluvium were formed in the ancient lake in beijing. in the middle of the pliocene, from 3.33 ma to 3.58 ma, the high-water level of the yanqing ancient lake broke through the last obstacle of the gorge section, and an unprecedented great flood occurred. the yongding river was formed which carries a large amount of gravel and sediment, eventually filling up the ancient lake in beijing, and the huge river fan group in beijing began to form. after the formation of the yongding river, and due to the activities of huangzhuang-gaoliying fault and yongding river fault, the outlet of the yongding river moved from junzhuang to sanjiadian. after the rivers emerged from the mountains, they changed their courses many times due to tectonic movement, and gradually moved from north to south. the large river fans formed by each diversion of the yongding river overlapped with each other and eventually shaped the present beijing plain. quaternary sediments extensively covered the beijing plain. its sedimentary system is composed of two large fans, which are the yongding river fan and the chaobai river fan. the yongding river was further divided into the no. 1 fan of the yongding river and the no. 2 fan of the yongding river (cai et al., 2009). the yongding river fan mainly covers the study area, with the overall sedimentary direction of fans i and ii of the yongding river being nw-se (fig. 11). in addition to analyzing the distribution characteristics of pebble deposits, the major direction of nw-se can also be observed (fig. 12). from this, the range’s major direction of all lithologies in the study area can be preliminarily determined. after the main directions were established, the variogram model of each lithology was developed by further statistical analy sis of the drilling data (table 1, figure 13). as can be seen in figure 13, although the variogram models of this research were not as typical as figure 5, their degrees of fit were better. 6. preliminary analysis of the three-dimensional structure of quaternary with the use of variogram models, five equal probability models of the quaternary were generated for the study. through discusfigure 13. continued. i) variogram model of clayey & sandy silt in the major direction, j) variogram model of clayey & sandy silt in the minor direction. i j g eo lo gi a c ro at ic a geologia croatica 72 / special issue14 urban area of beijing has undergone a great anthropogenic transformation. although the anthropogenic layer is widely distributed in the urban area of beijing, its single layer thickness is relatively thin (10m). after surface analysis, it was observed that the silty clay deposits in the middle of the study area gradually decreased and the pebble deposits gradually spread to the middle of the study area (fig. 15). continuous downward observation of the model sion with experts, a relatively accurate model was finally selected. as shown in figure 14, although backfill was not included in the modeling process, the software can replace the location of drills in the model with the corresponding drill information. while this can be used for model checking, it can also allow researchers to observe the distribution of the anthropogenic layer. the drill holes in the central part of the study area (urban area of beijing) are all backfill, demonstrating that the surface of the figure 14. geological model of the study area (with backfill of surface). figure 15. geological model of the study area (the 50 layer of model). g eologia c roatica xiao et al.: integrated 3d modeling of quaternary sediments in the beijing plain, based on a sequential indicator simulation 15 (fig. 16) shows that the pebble deposits still show a trend of spreading throughout the region. furthermore, the older deposits such as sandstone, silt and clay deposits gradually replace some younger deposits such as pebbles in the southeastern part of the study area. at the bottom of the model (fig. 17), it can be seen that the younger deposits such as pebble deposits are clearly reduced, and the older silt and clay deposits are clearly increased. figure 16. geological model of the study area (the 175 layer of model). figure 17. geological model of the study area (the 373 layer of model). g eo lo gi a c ro at ic a geologia croatica 72 / special issue16 the observational results of vertical characteristics of the quaternary sediment show that at the top of quaternary strata, the coarse-grained sediments such as pebbles and sandstones are mostly distributed at the edges of the study area. the fine-grained sediments such as silt and clay are mostly distributed in the depositional centre of the study area. in the middle of quaternary strata, pebble is mainly deposited. to the bottom of the quaternary strata, pebble deposits are replaced by some silt and clay fine-grained deposits. the tongzhou district (southeast of the study area) is the depositional centre of the no. 1 fan of the yongding river. it can be seen from the geological profile (fig. 18) that the two predominant kinds of coarse-grained sediments are mainly gravel and sand, with fine-grained sediments and sand in the middle. longitudinal observation of the model profile (fig. 19) shows that the top and bottom sediments in the tongzhou area are primarily sandstone and pebble sediments, with finegrained sediments and sand sandwiched in the middle. the overall vertical sedimentary law is approximately consistent with the actual sedimentary law. figure 18. schematic diagram of the geological section of the river fan (modified from cai et al., 2009). figure 19. geological section of the depocentre in the study area. 7. conclusion firstly, based on the sedimentary regularity of the quaternary alluvial fan in the beijing plain area and the regular distribution of lithological thicknesses in the study area from known drilling data, lithological variogram models were established. the threedimensional geological model of the quaternary in beijing was then developed using the sequential indicator simulation method. secondly, through the verification of the model and examples, it shows that the model is accurate and can be used for researchers to preliminarily understand the distribution characteristics of quaternary strata in beijing plain. in summary, this study utilized the integration of drilling information, a digital elevation model, a stratum sedimentary thickness plan and other data on the same platform. besides, the methodology shown here will provide researchers with a preliminary understanding of the underground three-dimensional structure of the study area. more importantly, it plays an important role in the establishment of earthquake early warning system, g eologia c roatica xiao et al.: integrated 3d modeling of quaternary sediments in the beijing plain, based on a sequential indicator simulation 17 active fault detection and land subsidence analysis. the author believes that with the increase of drilling data in the later period, the model can describe the quaternary strata more precisely. acknowledgement national key r&d program of china (grant no. 2017yfc1500604), the national natural science foundation of china (grant no. 51708524) and the program for innovative research team in china earthquake administration (earthquake disaster simulation and evaluation in mainland of china) supported this study. we are very thankful to all the researchers of the beijing earthquake agency for access to the drilling data. we also thank professor sun baitao for his assistance with choosing the topic, defining the conceptual framework and revising the manuscript. references antoine, p., rousseau, d.-d., degeai, j.-p., moine, o., lagroix, f., kreutzer, s., fuchs, m., christine, h., gauthier, c., svoboda, j. & lisá, l. (2013). high-resolution record of the environmental response to climatic variations during the last interglacial–glacial cycle in central europe: the loess-palaeosol sequence of dolní věstonice (czech republic).– quaternary science reviews, 67, 17–38. doi: 10.106/j.quascirev.2013.01.014 brkić, z. (2017): the relationship of the geological framework to the quaternary aquifer system in the sava river valley (croatia).– geologia croatica, 70/3, 201–213. doi:10.4154/gc.2017.12 cai, x.m., guo, g.x., luan, y.b. & liang, y.n. (2009b): quaternary geological features of beijing piedmont plain using 3-d structural method.– acta geologica sinica, 83/7, 1047~1056. cai, x.m., luan, y.b., guo, g.x. & liang, y.n. (2009a): 3d quaternary geological structure of beijing plain.– geology in china, 36/5, 1021–1029. cai, x.m., zhang, l., guo, g.x., you, s.n., fang, t.m., lv, j.b. & liang, y.n. (2016): new progress in the study of quaternary geology in beijing plain.– geology in china, 43/3, 1055–1066. doi: 10.12029/gc20160327. cao, d.y. & wang, z.g. (2004): direct 3d-interaction in 3d geological model visualization.– journal of china university of mining & technology, 33/4, 384–387. clayton, v. d. & andre, g. j. (1998): gslib: geostatistical software library and user’s guide, second edition.– usa: oxford university press. duan, t.x., liu, x.m., zhang, y.j. & xiao, s.q. (2007): discussion on geologic modeling with petrel.– lithologic reservoirs, 19/2, 102–107. feng, g.q., li, y., lin, z.h. & wang, y.m. (2001): application of sequential indicator simulation method to delineating sedimentary microfacies.– journal of southwest petroleum institute, 23/2, 1–2. grizelj, a., bakrač, k., horvat, m., avanić, r. & hećimović, i. (2017): occurrence of vivianite in alluvial quaternary sediments in the area of sesvete (zagreb, croatia).– geologia croatica, 70/1, 41–52. doi: 10.4154/gc.2017.01. guo, g.x., luan, y.b., ye, c. & cai, x.m. (2008): discussion on the lower boundary of quaternary system and its application in the beijing plain.– city geology, 13/2, 13–16. hao, s.g., ma, x.p., xia, z.k., zhao, c.h., yuan, s.x. & yu, j.c. (2002): the early holocene loess section in the donghulin site near zhaitang in beijing.– journal of integrative plant biology, 167/13, 420–429. kong, z.c. & du, n.q. (1980): vegetational and climatic changes in the past 30000~10000 years in beijing.– journal of integrative plant biology, 22/4, 330–338. lehmkuhl, f., potter, s., pauligk, a. & bosken, j. (2018): loess and other quaternary sediments in germany.– journal of maps, 14/2, 330–340. doi: 10.1080/17445647.2018.1473817. li, c.a. (1994): late cenozoic stratigraphic division and establishment of stratigraphic succession in the northeast of the beijing plain.– journal of stratigraphy, 18/2, 138–145. li, d.r., peng, y.m. & liu, q.s. (1979): subdivision of pliocene-pleistocene series in beijing plain.– geological sciences, 4, 342–349. li, l.y. & chen, h.h. (1992): comprehensive criteria for the n/q boundary in huairou area, beijing, china.– earth science, 17/6, 631–637. li, l.y. & chen, h.h. (1994): on magnetostratigraphy of the borehole hr88-1 in huairou area, beijing.– journal of stratigraphy, 18/1, 39–44. li, s.h., zhang, c.m. & tang, j. (1999): application of sequential indicator simulation method and its application in pucheng oilfield reservoir heterogeneity.– journal of jianghan petroleum institute, 21/1, 13–17. li, t.t. & wei, b. (2015): application of petrel in multi-point statistical geological mode ling.– petrochemical industry technology, 11, 105. liu, y. & zhou, k.f. (2018): gold anomaly identification and its uncertainty analysis in the west junggar belt, xinjiang.– earth science, 43/9, 3186–3199. doi: 10.3799/dqkx.2018.151 luan, y.b., guo, l., guo, g.x. & huang, x. (2008): geochemical character of trace elements from well n5 in the quaternary sediments and research of palaeoclimate, palaeoenvironmental.– city geology, 13/13, 18–22. pan, m., fang, y. & qu, h.g. (2006): discussion on several foundational issues in three-dimensional geological modeling.– geography and geo-information science, 23/3, 1–5. shan, q.s., yang, h.l. & liu, l.g. (1994): the environmental evolution of quaternary of beijing tongxian region.– beijing geology, 4, 1–7. shen, y.y., guo, g.x., xin, b.d., xu, l. & liu, j.r. (2015): three-dimensional geological structure model based on gms in shunyi and pinggu districts.– beijing. urban geology, 10/2, 67–71. song, j.b., tian, t. & gao, p. (2016): reservoir modeling of chang 6 in shijia oil block, qingpingchuan oilfield, ordos basin.– geology of shanxi, 34/1, 19–24. terhorst, b., kuhn, p., damm, b., hambach, u., meyerheintze, s. & sedov, s. (2013): palaeoenvironmental fluctuations as recorded in the loess-palaeosol sequence of the upper palaeolithic site krems-wachtberg.– quaternary international, 351, 67–82. doi: 10.1016/j.quaint.2013.03.045 velić, j. & durn, g. (1993): alternating lacustrine-marsh sedimentation and subaerial exposure phases during quaternary: prečko, zagreb, croatia.– geologia croatica, 46/1, 71–90. velić, j., saftić, b. & malvić, t. (1999): lithological composition and stratigraphy of quaternary sediments in the area of the jakuševec waste depository (zagreb, northern croatia).– geologia croatica, 52/2, 119–130. wang, h. (2017): application of geostatistics method in reservoir modeling.– petrochemical industry application, 36/10, 58–60. doi: 10.3969/j.issn.1673-5285.2017.10.014 wang, j.r., hu, l.t. & yin, w.j. (2014): comparison of 3d geological modelings in beishan gansu province.– journal of beijing normal university (natural science), 50/5, 478–482. wei, l.y., peng, g. & yan, f.h. (1997): climatic changes and their environmental effects during the last deglaciation in beijing area.– quaternary sciences, 2, 183–191. yao, y.f., ye, c., kou, x.y., xu, j.x., jia, s.m., du, n.q. & li, c.s. (2007): vegetation succession and climate changing since the late pliocene in tianzhu region in beijing.– journal of palaeogeography, 19/11, 45–58. yuan, b.y., deng, c.l., lu, j.b., jin c.z. & wu, y.s. (2002): a late quaternary accumulation period and the prehistoric flood in beijing plain.– quaternary sciences, 22/5, 474–480. yuan, f., ma, l., xu, d.c., wen, x.g. & liu, y.z. (2017): sequential indicator simulation method in the application of the coal seam roof lithology prediction.– progress in geophysics, 32/5, 2126–2131. doi: 10.6038 /pg20170537 zhang, z.b., wang, d. & ding, j.x. (1981): environmental changes since 13000 years ago in beijing region.– geological sciences, 3, 259–268. zhao, s.j., cheng, j., yin, g.m. & zan, l.h. (2008): palynological assemblages and palaeoclimatic significance in beijing plain area since the middle pleistocene.– journal of palaeogeography, 110/16, 637–646. zhao, s.x. & liu, y.j. (2007): 3d visualizing of active fault surveying data.– seismology and geology, 29/4, 787–795. zhao, x.t., sun, x.p. & zhang, y.l. (1984): the palaeogeographic evolution since 30000 years ago in beijing plain.– china science, 6, 544–554. zhou, k.s., yan, f.h. & liang, x.l. (1987): pollen analysis of late quaternary in beijing plain and significance.– geological science, 1, 57–64. zhou, l.m. (2017): application of geostatistics inversion in the sandstone reservoir characterization of delta riverway.– chenmical intermediate, 1, 43–44. zhu, l.f., sun, j.z. & zhang, c.j. (2012): construction method of three-dimensional solid models for sedimentary stratigraphic systems.– rock and soil mechanics, 33/11, 3243–3250. doi: 10.16285/j.rsm.2012.11.007. 2022 | 75/2 | 249–267 | 11 figs. | 4 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction mt. papuk, situated at the southern edge of the pannonian basin in northern croatia (fig. 1a), is characterized by a complex geological evolution that comprises several orogenic events (jamičić, 1983; balen et al., 2006, 2013; horváth et al., 2010). these events led to a variety of rocks and complexes such as granitoids and metamorphic complexes of pre-variscan, variscan and alpine ages. together with late permian–jurassic sedimentary rocks, these complexes are part of the tisia megaunit and are surrounded by neogene and quaternary sedimentary rocks and sediments of the pannonian basin (jamičić, 1983, 1988; pamić et al., 1988; pamić & lanphere, 1991a). in addition to the rocks of the tisia mega-unit and those of the pannonian basin, there are relatively small occurrences of volcanic rocks in the vicinity of the town of voćin (jamičić & brkić, 1986; jamičić et al., 1987, 1989; jamičić, 1989; pamić, 1991). among them are rocks of the senonian basaltrhyolite formation (pamić, 1997), outcropping at mt. papuk near voćin known as the voćin volcanic mass (pamić, 1991). these rocks are difficult to distinguish from similar-looking miocene volcanic rocks in northern croatia. based on micropalaeontological records and geological relationships (jamičić & brkić, 1986; jamičić et al., 1987, 1989; jamičić, 1989; belak et al., 2000), it is concluded that the miocene rocks are related to the evolution of the pannonian basin. the age of the voćin volcanic rocks is questionable, because only k-ar dating on associated basalts (72.8–51.7 ma, pamić, 1991) and basalt cores from dating and geochemistry of zircon and apatite from rhyolite at the unesco geosite rupnica (mt. papuk, northern croatia) and the relationship to the sava zone petra schneider1,*, dražen balen1, joachim opitz2 and hans-joachim massonne2 1 university of zagreb, faculty of science, department of geology, horvatovac 95, 10000 zagreb, croatia; (*corresponding author: pschneider@geol.pmf.unizg.hr), (drbalen@geol.pmf.unizg.hr) 2 universität stuttgart, institut für mineralogie und kristallchemie (closed), azenbergstraβe 18, 70174 stuttgart, germany; (opitz.joachim@web.de, h-j.massonne@imi.uni-stuttgart.de) doi: 10.4154/gc.2022.19 abstract the rupnica geosite, a key locality of the unesco-protected papuk geopark in northern croatia, is well-known for an excellent exposure of columnar jointing in volcanic rock. this rock is defined as an albite rhyolite that comprises almost pure albite phenocrysts within a fine-grained matrix composed of microphenocrysts of albite, quartz and devitrified volcanic glass. primary accessory minerals are clinopyroxene, apatite, zircon and magnetite. haematite, apatite and anatase were found as inclusions in zircon. the albite rhyolite is characterized by a highly siliceous, peraluminous, oxidized (ferroan), dry, alkali-calcic to alkalic composition, with low cao, mgo, and mno contents and high feot/(feot+mgo) ratios. normalized trace element contents display positive anomalies of k, pb, and zr as well as negative anomalies of nb, p, ti, ba and eu, together with an enrichment of light rare-earth elements (ree) relative to heavy ree. zircon from the rhyolite of rupnica is characterized by ratios of th/u=1.13 and zr/hf=55 and contents of hfo2=1.04 wt. % typical for an early-stage igneous zircon crystallized from a dry high-temperature magma in a deep magma chamber. apatite ree patterns show enrichment of light ree over heavy ree and a pronounced eu anomaly, typical for apatite from granitoids formed in an oxidizing environment. the magma is of a-type and was generated at high temperatures at 800–900 °c by partial melting of lowerto mid-crustal rocks. the age of the albite rhyolite of rupnica is late cretaceous at 80.8±1.8 (2σ) ma, according to u-pb dating of zircon, coeval with geochemically similar igneous rocks of mt. požeška gora and mt. kozara within the sava zone. šnajder i borojević drillholes across the sava depression (83.4–32 ma, pamić, 1997) are available. the similar petrography and appearance of the voćin and miocene volcanic rocks, as well as the lack of reliable dating led to the above-mentioned age controversies, which also led to different views on the petrogenesis and geodynamic setting of the voćin rocks. the rupnica locality is a key outcrop of the voćin volcanic rocks with an excellent exposure of columnar jointing (balen & petrinec, 2014), and is the first protected geosite, i.e. “geological monument of nature”, in croatia. the exposed rocks are albite and aegirine-albite rhyolites (tajder, 1956, 1960). although these rocks are exposed in a part of the tisia mega-unit, they do not belong to it because volcanic rocks cross-cut through the rocks of the tisia mega-unit (jamičić & brkić, 1986). intense magmatic activity also took place in the late cretaceous within the adjacent geotectonic unit called the sava (-vardar) zone (pamić, 1993) or sava suture zone (schmid et al., 2008, 2020). the timing of geological processes in this zone and the geochemical features of volcanic rocks also show similarities to the characteristics of the voćin volcanic rocks at the rupnica locality. for this reason, we re-evaluated the petrographic and geochemical signatures of the albite rhyolite of rupnica and determined the trace and isotopic geochemistry of zircon and apatite to unravel and reconstruct the origin, evolution and especially the age of this rock. albite rhyolite is a type of acidic high-temperature volcanic rock, which compared to ordinary rhyolite, has high alkali conarticle history: manuscript received september 15, 2021 revised manuscript accepted april 19, 2022 available online june 23, 2022 keywords: zircon, apatite, rhyolite, cretaceous, papuk geopark, sava zone g eo lo gi a c ro at ic a geologia croatica 75/2250 tents (with na predominating over k) and shows low concentrations of ca and mg (tajder, 1953, 1960; balen & petrinec, 2014). moreover, albite rhyolite is often subjected to various alteration processes with zircon being the only remaining primary magmatic and unaltered mineral suitable for dating. in addition, the determination of minor and trace elements in zircon and apatite can provide further geochemical information on magma evolution and petrogenesis. our u-th-pb zircon dating, which is an improvement of previous age estimates, opens the link to the occurrence of igneous rocks with similar geochemistry and age in the vicinity of the rupnica site. 2. geological setting 2.1. tisia mega-unit the geology of mt. papuk is dominated by the tisia (also tisza, tisa) mega-unit. this complex and composite unit is regarded figure 1. simplified maps of the dinaride-alpine-pannonian region showing: (a) the mountain belts and pannonian basin and (b) major structural units after schmid et al. (2008, 2020). map modified after lužar-oberiter et al. (2012). (c) mt. papuk geological map (after jamičić & brkić 1986; jamičić et al. 1987, 1989; jamičić 1989; croatian geological survey 2009). the position of the study area is marked by the rectangle and circled stars. legend: 1 – metamorphic rock complex (precambrian); 2 – progressive metamorphic series (ordovician-devonian); 3 – metamorphic rock complex (ordovician-devonian); 4 – granitic rocks (ordovician-devonian); 8 – variscan/hercynian semi-metamorphic complex (devonian-permian); 13b – clastic sedimentary deposits (late permian); 14 – clastic sedimentary deposits and carbonates (early triassic); 15 – carbonate deposits (middle triassic); 27 – limestones (jurassic); 44 – clastic sedimentary deposits and carbonates (miocene, m2,3); 46 – “litavac” (bioclastic beech carbonate) and clastic sedimentary deposits with volcanic rocks (miocene, m4); 47 – carbonate clastic deposits (miocene, m5,6); 48 – clastic sedimentary rocks and coal (miocene, m7); 52 – clastic deposites (plio-quaternary); 54a – loess (pleistocene); 58b – alluvial deposits (holocene); α – andesites and rhyolites (miocene, m3,4). g eologia c roatica schneider et al.: dating and geochemistry of zircon and apatite from rhyolite at the unesco geosite rupnica (mt. papuk, northern croatia) ... 251 as a continental fragment which rifted and drifted away from europe in the middle jurassic as a consequence of kinematically linked opening of the easternmost branch of the alpine tethys ocean (ceahlau-severin ocean) (schmid et al., 2020). the final emplacement of the tisia mega-unit into the present-day configuration took place during the palaeogene and miocene, i.e. after its internal structuring, which mainly occurred during a cretaceous orogeny (schmid et al., 2020). only small parts of this unit are exposed in rare isolated and rather small so-called inselbergs within the pannonian basin, such as the mecsek and villany mts. of hungary, the northern apuseni mts. in romania and the slavonian mts. in croatia (fig. 1b). the slavonian mts. include the mt. papuk area where pre-variscan, variscan and alpine igneous and metamorphic rocks crop out (fig. 1c; balen et al., 2015, 2018; biševac et al., 2010; horvat et al., 2018; slovenec et al., 2020). 2.2. sava zone the western branch of the neotethys ocean was closed through convergence of the adria microplate (dinarides) and europe (tisia). this convergence caused the formation of a suture zone named the sava-vardar zone (pamić, 2002), sava zone or sava suture zone (schmid et al., 2008, 2020). the sava zone is a complex belt comprising ophiolites and related igneous, metamorphic and sedimentary rocks, including cretaceous to eocene deep water sediments and flysch. late cretaceous ophiolites represent the structurally lowermost unit of the sava zone. this zone runs from zagreb towards belgrade, and then further to the south through the vardar zone into greece (fig. 1b; schmid et al., 2008; ustaszewski et al., 2010). the northwestern end of the sava zone close to zagreb sharply turns into the sw-ne strike of the mid-hungarian fault zone and is further buried below the cenozoic cover of the pannonian basin (schmid et al., 2020). the formation age of the sava zone ranges from the cretaceous to the early palaeogene until the final collision of the dinarides with the tisia mega-unit (pamić, 2002). the relatively rare late mesozoic and cenozoic igneous rocks within the sava zone are related to magmatism along the europe-adria suture zone. known occurrences of these rocks (fig. 1b) are in northern bosnia (mts. kozara, prosara and motajica), northern serbia (mt. fruška gora) and eastern croatia (mts. požeška gora and moslavačka gora) (e.g. schmid et al., 2008). 2.3. senonian basalt-rhyolite formation in part of the slavonian mts. pamić (1997) described a senoni an basalt-rhyolite formation including a-type granites. rocks of this formation crop out in the areas of mt. požeška gora (with the only known surface occurrence of a-type granite at the gradski vrhovci locality; pamić, 1987; pamić & lanphere, 1991a) and mt. papuk. the volcanic rocks at the latter locality, the socalled voćin volcanic mass (pamić, 1997), are situated at the northern slopes of mt. papuk, near the town of voćin, and include the rocks from the rupnica locality. the voćin volcanic mass consists of basalts, rhyolites and pyroclastic rocks, covers an area of ~10 km2 (pamić, 1991), and penetrates the igneous, metamorphic and sedimentary rocks of surrounding complexes (fig. 1c). pamić (1991) proposed a late cretaceous age for the volcanic rocks in the immediate area of voćin, while the volcanic and pyroclastic rocks in the wider area were considered to be miocene in age (jamičić et al., 1987, 1989; belak et al., 2000). the whole-rock k-ar dating at 72.8‒51.7 ma presented in pamić (1991) was conducted on basalts. the older ages were obtained on relatively fresh basalts, whereas the younger ones resulted from the study of altered basalts (spilites). younger ages were interpreted as a consequence of a loss of radiogenic ar, possibly during the younger volcanic activity in the area, which also produced spatially associated basalts. furthermore, k-ar dating was performed on basalt cores from drillholes across the sava depression (pamić, 1997) with ages between 83.4 and 32 ma. 2.4. a-type granite of mt. požeška gora the a-type granite of mt. požeška gora (pamić, 1987; pamić et al., 1988/89; pamić & lanphere, 1991b) has been reinvestigated in detail by balen et al. (2020), who confirmed a late cretaceous age (83.6±1.5 ma) by u-th-pb dating on zircon. this recent study revealed the significance of this rather small granite body because it marks the activation of deep faults in an extensional tectonic environment at the suture zone, where the subduction of the adria plate under the european plate took place. therefore, this a-type granite indicates the local tectonic transition from compression to extension. the idea of a connection between the late cretaceous (senonian) volcanic masses at mt. požeška gora and mt. papuk was already postulated by pamić (1997). therefore, it is of interest to compare the geochemical features of rhyolite at the rupnica site, its accessory minerals and the crystallization age of zircon, with the same features of the atype granite from mt. požeška gora. 2.5. miocene volcanic rocks a detailed description of volcanic rocks from the northwestern part of mt. papuk (including voćin and its surroundings) can be found in lugović (1983), where an overview of the age constraints based on earlier reports is given. in these historical papers (stur, 1861/62; koch, 1919; poljak, 1939), besides details on field relationships, the prevailing opinion is that these rocks are of miocene age. in the basic geological map of croatia m 1:300,000 (croatian geological survey, 2009) volcanic rocks at voćin and its surroundings are described as andesites and rhyolites of miocene age (fig. 1c), as it was postulated in the basic geological map of sfry 1:100.000, sheets orahovica and daruvar (jamičić & brkić, 1986; jamičić et al., 1987, 1989; jamičić, 1989). the contact of the voćin volcanic rocks with the triassic and late cretaceous deposits is described as tectonic. according to the interpretation in the above mentioned explanatory notes, the volcanic activity was accompanied by sedimentary processes related to the evolution of the pannonian basin. 3. analytical methods 3.1. whole-rock chemistry from 20 collected homogeneous samples at the rupnica geosite, 3 samples plus 1 used in balen & petrinec (2014) were selected for whole-rock geochemistry. these samples were crushed in a jaw crusher, powdered in an agate mill, and analysed at the bureau veritas commodities canada ltd. (vancouver) by inductively coupled plasma mass spectrometry (icp-ms; trace elements including rare-earth elements (ree)) and inductively coupled plasma emission spectrometry (icp-es; major elements). powders were air-dried and sieved through a 0.125 mm stainlesssteel screen. the sample preparation included the splitting of 0.2 g rock powder each for libo2/li2b4o7 fusion for icp-es and icp-ms. natural rocks of known composition and pure quartz were used as reference materials. the analytical accuracy was g eo lo gi a c ro at ic a geologia croatica 75/2252 table 1. results of the whole-rock analyses of major (wt. %) and trace (ppm) elements with characteristic element ratios and zircon saturation temperatures (zst) after watson & harisson (1983) and gervasoni et al. (2016) for selected samples of rhyolite of rupnica. the compositions were determined with icp-ms and icp-es. sample 1 is from balen & petrinec (2014). major elements (wt. %) sample 1 rup sample 2 rupnica 3 sample 3 rup4 sample 4 rup7 d.l. (wt. %) min max mean sio2 66.41 66.83 69.5 68.27 0.01 66.41 69.50 67.75 tio2 0.45 0.42 0.41 0.41 0.01 0.41 0.45 0.42 al2o3 16.7 15.61 15.35 15.53 0.01 15.35 16.70 15.80 fe2o3 3.87 3.72 3.53 4.22 0.04 3.53 4.22 3.84 mno 0.03 0.07 0.05 0.04 0.01 0.03 0.07 0.05 mgo 0.53 0.48 0.27 0.38 0.01 0.27 0.53 0.42 cao 0.36 1.48 0.35 0.36 0.01 0.35 1.48 0.64 na2o 5.6 5.29 5.27 5.22 0.01 5.22 5.60 5.35 k2o 3.41 2.91 3.47 3.23 0.01 2.91 3.47 3.26 p2o5 0.12 0.11 0.1 0.11 0.01 0.10 0.12 0.11 loi 2.40 2.90 1.60 2.10 0.01 1.60 2.90 2.25 total 99.88 99.82 99.9 99.87 99.82 99.90 99.87 trace elements (ppm) (ppm) as 3.2 1.2 1.4 8.5 0.5 1.2 8.5 3.575 au (ppb) 0.3 1.9 32.4 28.1 0.5 (ppb) 0.3 32.4 15.7 ba 548 459 492 512 1 459 548 503 be 4 2 2 3 1 2 4 2.75 co 1.3 2.7 0.8 2.8 0.2 0.8 2.8 1.9 cs 0.4 <0.1 0.5 0.7 0.1 0.4 0.7 0.5 cu 1.3 16.2 7.3 14.7 0.1 1.3 16.2 9.9 ga 20 21 18 16 0.5 16.4 20.8 18.6 hf 9.0 9.5 7.6 7.9 0.1 7.6 9.5 8.5 mo 0.6 0.6 0.5 0.5 0.1 0.5 0.6 0.6 nb 26 27 22 25 0.1 22 27 25 ni 1.5 2.9 0.9 2.3 0.1 0.9 2.9 1.9 pb 3.7 8.4 11.0 14.6 0.1 3.7 14.6 9.4 rb 45 44 55 52 0.1 44 55 49 sb <0.1 0.2 0.5 0.4 0.1 0.2 0.5 0.4 sc 7 7 6 7 1 6 7 7 sn 4 4 4 4 1 4 4 4 sr 134 175 129 117 0.5 117 175 139 ta 1.7 1.7 1.6 1.4 0.1 1.4 1.7 1.6 th 9.4 9.8 8.8 7.7 0.2 7.7 9.8 8.9 u 2.0 2.1 2.0 2.1 0.1 2.0 2.1 2.1 v 11 17 12 14 8 11 17 13.5 w 1.5 2.0 1.3 1.5 0.5 1.3 2.0 1.6 y 32 37 29 32 0.1 29 37 32 zn 59 70 48 66 1 48 70 61 zr 354 386 329 339 0.1 329 386 352 la 29 33 29 18 0.1 18 33 27 ce 63 60 55 49 0.1 49 63 57 pr 6.6 6.9 6.6 4.4 0.02 4.4 6.9 6.1 nd 25 27 26 17 0.3 17 27 24 sm 5.6 5.7 5.6 4.1 0.05 4.1 5.7 5.3 eu 1.4 1.4 1.3 1.0 0.02 1.0 1.4 1.3 gd 5.9 6.4 5.1 5.2 0.05 5.1 6.4 5.6 tb 1.1 1.1 0.9 0.9 0.01 0.9 1.1 1.0 dy 6.0 6.4 5.8 5.6 0.05 5.6 6.4 5.9 ho 1.2 1.4 1.2 1.1 0.02 1.1 1.4 1.2 er 3.6 4.2 3.2 3.4 0.03 3.2 4.2 3.6 tm 0.6 0.6 0.5 0.5 0.01 0.5 0.6 0.5 yb 3.4 3.9 3.3 3.5 0.05 3.3 3.9 3.5 lu 0.5 0.6 0.5 0.6 0.01 0.5 0.6 0.5 g eologia c roatica schneider et al.: dating and geochemistry of zircon and apatite from rhyolite at the unesco geosite rupnica (mt. papuk, northern croatia) ... 253 controlled using internal geological reference materials, the compositions of which are comparable to the rocks in this study (stdgs311-1, std gs910-4, std ds10, std oreas45ea, std so-19). detection limits are shown in table 1. reference materials were certified in-house by analysis with canmet certified reference materials. loss on ignition (loi) was determined by weight difference before and after 4 hours ignition at 1000 °c. geochemical data and diagrams are recalculated and handled with the gcdkit software (janoušek et al., 2006). 3.2. scanning electron microscopy zircon was separated from the rhyolite (sample rupnica 3) by a standard procedure of extraction from the host rock (crushing of the rock, sieving, heavy-liquid separation with sodium polytungstate and magnetic separation) and analysed using scanning electron microscopy at the slovak academy of sciences, earth science institute, laboratory of electron microscopy in banska bystrica, in order to detect the external morphology of individual zircon grains. the analyses were performed with a jeol jsm6390lv equipped with a secondary electron detector for imaging and an acceleration voltage of 20 kv. the specimens were coated with gold. 3.3. raman spectroscopy separated zircon grains were also analysed with the aid of microraman spectroscopy in order to characterize the inclusions in zircon. this spectroscopy was performed at the slovak academy of sciences, earth science institute, laboratory of vibration spectroscopy in banska bystrica with a horiba jobin-yvon labram hr 800 spectrometer equipped with a czerny-turner monochromator, 600 grooves per mm grating, and a peltiercooled charge-coupled device detector coupled to an olympus bx41 microscope with a long working distance 100×/0.8 objective. zircon crystals were irradiated by a he–ne (633 nm) laser with a power of ~3 mw. a frequency-doubled nd:yag (532 nm) laser was only used for verifying possible luminescence effects. the rayleigh line (0 cm-1) and emission bands of ne glow lamps were used for calibration. wave-number accuracy and lateral reso lution were better than 0.8 cm−1 and 1 µm, respectively. the spectral resolution was ~3.6 cm−1 (red spectral range). the spectra of the unknown phases were collected in the range of 60–4000 cm−1 to additionally cover the region of oh-stretching bands. 3.4. laser ablation – inductively coupled plasma – mass spectrometry (la-icp-ms) isotopic concentrations of selected elements in zircon were determined by la-icp-ms. analyses were performed at the institut für mineralogie und kristallchemie, universität stuttgart (germany), using an agilent 7700 mass spectrometer after laser ablation with a cetac lsx-213 laser system. the diameter of the ablated spots was 25 µm. the laser energy was set to 100 % of the maximum (100 % = 4 mj at a spot diameter of 150 µm) at a laser pulse frequency of 10 hz and 330 (for elemental concentrations) or 375 (for dating) laser pulses per analysis. a mixed he and ar gas flow with 500 ml/min and 800 ml/min, respectively, served as carrier of the ablated material into the icp-ms system. zircon grains separated from the rhyolite were mounted in an epoxy resin and polished approximately to their centres. the details of the data evaluation methods and corrections are given in balen et al. (2020). 3.4.1. zircon chemical analysis glass standards for the determination of elemental concentrations in zircon were the following: dlh7 and dlh8 from p&h developments ltd. and nist612 and nist610 from national institute of standards and technology, usa. the validity of the calibration, data evaluation, and reproducibility were checked with the sample 1 rup sample 2 rupnica 3 sample 3 rup4 sample 4 rup7 min max mean mi 0.87 0.87 0.92 0.91 0.87 0.92 0.89 a/cnk 1.24 1.08 1.19 1.23 1.08 1.24 1.19 a/nk 1.29 1.32 1.24 1.29 1.24 1.32 1.28 k2o/na2o mol 0.40 0.36 0.43 0.41 0.36 0.43 0.40 ba/rb 12.1 10.6 9.0 9.8 9.0 12.1 10.4 10000·ga/al 2.2 2.5 2.2 2.0 2.0 2.5 2.2 zr/hf 39 41 43 43 39 43 42 y/ho 26 27 25 28 25 28 26 (la/yb)n 5.75 5.70 5.92 3.47 3.47 5.92 5.21 (la/sm)n 3.26 3.64 3.26 2.76 2.76 3.64 3.23 (gd/yb)n 1.40 1.32 1.25 1.20 1.20 1.40 1.29 ce/ce* 1.10 0.96 0.96 1.33 0.96 1.33 1.08 eu/eu* 0.74 0.71 0.74 0.66 0.66 0.74 0.71 σ ree 152 159 142 115 115 159 142 m 1.33 1.50 1.33 1.27 1.27 1.50 1.36 twh (°c) 866 860 858 867 858 867 863 g 8.20 7.81 8.98 8.51 7.81 8.98 8.38 tg (°c) 789 778 798 790 778 798 789 d.l. = detection limit; loi = loss on ignition; mi (mafic index) = feot/(feot+mgo); a/cnk = al2o3/(cao+na2o+k2o) in mol%; a/nk = al2o3/(na2o+k2o); m (cation ratio) = (na+k+2ca)/al·si; g = (3·al2o3+sio2)/(na2o+k2o+cao+mgo+feo) in molar proportions; twh and tg − zircon saturation temperatures after watson & harisson (1983) and gervasoni et al. (2016), respectively. table 1. continued. g eo lo gi a c ro at ic a geologia croatica 75/2254 ta bl e 2. c he m is tr y of z irc on fr om th e rh yo lit e of r up ni ca d et er m in ed b y la -ic pm s w ith c ha ra ct er is tic e le m en t r at io s a nd d et ec tio n lim its (d .l. ). el em en ta l m as s c on ce nt ra tio ns a nd d et ec tio n lim its a re g iv en in p pm . t i-i nzi rc on te m pe ra tu re w as c al cu la te d fo r s el ec te d gr ai ns a ft er w at so n e t a l. (2 00 6) . b .d .l. – b el ow d et ec tio n lim it. el em en t g ra in 1 a g ra in 2 a g ra in 3 a g ra in 4 a g ra in 5 a g ra in 6 a g ra in 7 a g ra in 8 a g ra in 9 a g ra in 1 0a g ra in 1 1a g ra in 1 2a g ra in 1 3a g ra in 1 4a d. l. m in m ax m ea n m ed ia n ba 0. 7 1. 0 0. 9 0. 8 1. 3 5. 0 0. 9 1. 5 1. 0 1. 6 1. 7 4. 2 13 .1 3. 9 0. 4 0. 7 13 2. 7 1. 4 ca 20 14 0 12 59 2 88 71 b. d. l. 14 40 9 34 73 0 27 97 8 15 07 9 15 17 4 32 29 1 62 27 37 44 41 19 25 62 4 77 0 37 44 34 73 0 16 99 8 15 07 9 cr 3. 5 3. 8 2. 1 2. 7 3. 2 3. 6 2. 0 3. 5 3. 9 3. 6 3. 0 2. 9 3. 9 2. 1 2 2. 0 3. 9 3. 1 3. 3 fe 65 2 42 6 75 1 32 3 35 6 45 18 21 19 68 3 27 0 95 4 38 9 34 7 20 06 76 3 33 27 0 45 18 10 40 66 7 g a 1. 1 b. d. l. b. d. l. b. d. l. 1. 1 2. 6 1. 3 3. 1 0. 6 1. 1 1. 5 b. d. l. 1. 0 1. 3 0. 4 0. 6 3. 1 1. 5 1. 2 h f 97 91 72 83 11 51 1 93 48 91 13 78 34 94 05 11 34 2 76 46 74 47 94 11 64 36 77 71 86 35 0. 3 64 36 11 51 1 87 84 88 74 m n 52 28 24 5. 9 45 10 3 13 7 53 67 78 28 17 52 77 2 5. 9 13 7 55 52 n b 9. 0 4. 4 7. 6 9. 9 15 28 8. 5 25 13 7. 9 13 9. 0 8. 0 7. 4 0. 04 4. 4 28 12 9. 0 p 82 80 65 39 34 02 91 1 10 09 7 12 97 2 13 34 6 96 97 68 84 14 37 2 25 29 31 82 25 92 12 59 0 14 8 91 1 14 37 2 76 71 75 82 pb 4. 2 2. 3 5. 6 10 7. 2 8. 9 5. 0 11 5. 1 3. 6 6. 5 12 11 7 3. 5 0. 2 2. 3 11 7 14 6. 1 si 15 14 00 15 14 00 15 14 00 15 14 00 15 14 00 15 14 00 15 14 00 15 14 00 15 14 00 15 14 00 15 14 00 15 14 00 15 14 00 15 14 00 12 23 15 14 00 15 14 00 15 14 00 15 14 00 sn 1. 0 b. d. l. b. d. l. b. d. l. b. d. l. 2. 0 1. 3 b. d. l. 1. 0 1. 0 1. 2 b. d. l. b. d. l. b. d. l. 0. 8 1. 0 2. 0 1. 2 1. 1 sr 23 14 6. 6 1. 6 18 35 31 17 12 29 12 4. 5 4. 4 27 0. 1 1. 6 35 17 16 ta 2. 8 1. 2 2. 1 2. 4 3. 3 2. 8 2. 6 5. 2 2. 7 1. 3 3. 3 1. 8 2. 0 1. 9 0. 04 1. 2 5. 2 2. 5 2. 5 th 40 5 10 7 30 2 42 5 79 9 87 1 53 9 14 11 55 8 27 2 71 5 33 7 35 0 34 8 0. 1 10 7 14 11 53 1 41 5 ti 78 15 2 34 19 21 49 0 41 38 21 60 5 10 8 55 26 89 2 19 60 5 12 7 48 u 40 0 13 7 29 1 38 0 66 7 53 6 46 6 95 8 50 5 28 2 58 8 34 2 33 6 32 0 0. 1 13 7 95 8 44 3 39 0 v 0. 6 0. 6 0. 2 0. 3 0. 1 1. 6 0. 9 0. 3 0. 2 0. 7 0. 2 0. 3 0. 6 0. 3 0. 2 0. 1 1. 6 0. 5 0. 3 y 36 25 11 78 36 56 37 10 61 54 44 65 35 70 59 97 52 23 31 27 49 20 35 77 23 15 29 75 0. 2 11 78 61 54 38 92 36 41 zn 7. 9 13 23 26 2 9. 9 29 15 14 7. 5 22 13 61 6 16 89 7. 3 2 7. 3 16 89 19 5 14 zr 45 21 14 43 23 94 48 84 23 52 53 78 48 04 23 44 67 24 49 17 55 50 89 04 48 15 39 45 31 72 48 65 56 43 88 20 45 12 41 46 76 46 8 43 23 94 52 53 78 47 17 92 47 40 34 la 63 23 17 3. 5 75 11 9 99 63 54 95 89 20 14 73 0. 06 3. 5 11 9 58 63 .0 ce 14 9 72 58 25 20 7 37 2 25 2 23 6 13 4 22 3 24 8 61 37 17 7 0. 08 25 37 2 16 1 16 3 pr 20 7. 6 5. 3 1. 5 23 52 40 30 14 29 34 6. 3 3. 7 25 0. 03 1. 5 52 21 21 n d 12 3 39 32 14 13 9 25 7 17 2 17 0 76 12 8 17 4 29 21 12 7 0. 26 14 25 7 10 7 12 5 sm 44 13 22 17 80 71 49 77 44 45 68 19 19 40 0. 29 13 80 43 44 eu 5. 5 1. 7 3. 9 2. 7 9. 9 7. 8 6. 0 8. 3 6. 3 5. 1 6. 8 2. 7 3. 2 4. 4 0. 07 1. 7 9. 9 5. 3 5. 3 g d 11 4 27 94 86 23 5 15 6 12 9 22 7 15 7 10 0 16 4 80 69 89 0. 22 27 23 5 12 3 10 7 tb 32 9. 0 28 28 65 40 36 59 47 28 42 24 22 27 0. 03 9. 0 65 35 30 d y 39 5 11 0 29 1 34 1 69 3 40 3 36 9 55 8 52 7 32 8 53 4 25 4 24 9 33 9 0. 23 11 0 69 3 38 5 35 5 h o 14 3 46 12 7 12 7 21 9 15 1 12 9 18 2 19 0 11 7 16 7 89 86 11 8 0. 04 46 21 9 13 5 12 8 er 64 1 22 9 67 0 59 3 86 9 65 2 57 0 88 4 78 7 53 3 74 1 40 0 37 1 49 5 0. 11 22 9 88 4 60 2 61 7 tm 12 6 47 14 1 11 4 15 9 12 3 12 1 17 7 15 3 10 3 14 5 82 71 10 1 0. 05 47 17 7 11 9 12 2 yb 11 20 44 4 11 22 94 4 13 77 98 3 10 71 15 17 12 39 87 4 12 35 71 1 58 5 87 7 0. 29 44 4 15 17 10 07 10 27 lu 22 2 87 22 6 18 1 27 7 17 0 20 3 30 2 21 4 15 9 22 4 13 6 11 2 17 0 0. 04 87 30 2 19 2 19 2 su m r ee 31 96 11 55 28 36 24 79 44 27 35 57 32 46 44 90 36 42 27 69 38 70 19 14 16 62 26 62 11 55 44 90 29 93 30 16 su m o xi de s ( w t % ) 10 0. 44 95 .3 8 10 2. 78 10 5. 75 10 4. 28 10 3. 44 10 8. 24 10 8. 54 10 3. 36 10 3. 38 10 2. 04 94 .6 2 96 .5 7 10 4. 01 94 .6 2 10 8. 54 10 2. 35 10 3. 37 h fo 2 11 54 7 85 88 13 57 4 11 02 4 10 74 7 92 39 11 09 2 13 37 6 90 17 87 82 11 09 8 75 90 91 64 10 18 4 75 90 13 57 4 10 37 2 10 74 7 y 2 o 3 46 03 14 95 46 43 47 11 78 15 56 70 45 34 76 16 66 33 39 72 62 48 45 43 29 40 37 78 14 95 78 15 50 33 46 43 th /u 1. 01 0. 78 1. 04 1. 12 1. 20 1. 62 1. 16 1. 47 1. 11 0. 97 1. 22 0. 99 1. 04 1. 09 0. 78 1. 62 1. 13 1. 10 zr /h f 46 59 42 56 53 57 52 45 63 61 52 68 58 54 42 68 55 55 .2 n b/ ta 3. 2 3. 7 3. 7 4. 0 4. 5 10 .0 3. 3 4. 8 4. 8 6. 3 4. 0 5. 0 4. 0 3. 9 3. 2 10 4. 7 4. 0 ce /c e* 1. 01 1. 31 1. 47 2. 63 1. 20 1. 14 0. 96 1. 31 1. 17 1. 02 1. 09 1. 31 1. 24 1. 00 0. 96 2. 63 1. 27 1. 19 eu /e u* 0. 24 0. 28 0. 26 0. 22 0. 22 0. 23 0. 23 0. 19 0. 23 0. 23 0. 20 0. 21 0. 27 0. 23 0. 19 0. 28 0. 23 0. 23 la n /y b n 0. 04 0. 03 0. 01 0. 00 0. 04 0. 08 0. 06 0. 03 0. 03 0. 07 0. 05 0. 02 0. 02 0. 06 0. 00 0. 08 0. 04 0. 04 la n /s m n 0. 90 1. 11 0. 49 0. 13 0. 59 1. 05 1. 27 0. 51 0. 77 1. 33 0. 82 0. 66 0. 46 1. 15 0. 13 1. 33 0. 80 0. 80 g d n /y b n 0. 08 0. 05 0. 07 0. 07 0. 14 0. 13 0. 10 0. 12 0. 10 0. 09 0. 11 0. 09 0. 10 0. 08 0. 05 0. 14 0. 09 0. 09 ti -in -z irc on (° c) 80 1 81 2 81 2 83 1 80 1 83 1 81 4 81 2 g eologia c roatica schneider et al.: dating and geochemistry of zircon and apatite from rhyolite at the unesco geosite rupnica (mt. papuk, northern croatia) ... 255 reference materials diorite (drn) and zinnwaldite (zw-c) from service d’analyses des roches et des minéraux du cnrs. relative elemental concentrations were calculated from the abundance of the corresponding isotopes, assuming natural isotopic distributions and individual calibration factors, which were determined under the same experimental conditions. absolute elemental concentrations were calculated on the basis of the known absolute elemental concentration of an internal reference element. for zircon chemical analysis, the following isotopes were monitored: 28, 29si, 31p, 42, 44ca, 45sc, 49ti, 51v, 52cr, 55mn, 56, 57fe, 59co, 60ni, 66zn, 71ga, 88sr, 89y, 90, 91zr, 93nb, 118sn, 137ba, 139la, 140ce, 141pr, 146nd, 147, 149sm, 151, 153eu, 157gd, 159tb, 161, 163dy, 165ho, 166er, 169tm, 172yb, 175lu, 177, 178hf, 181ta, 208pb, 232th and 238u. all elemental concentrations were calculated relative to si=15.14 wt. %, a value which is taken as an internal reference value in zircon, because si is least likely to be replaced by other elements in the zircon structure. therefore, the mean value of si, as derived from the isotopes 28, 29si, was set to 151,400 ppm. the calculated elemental concentrations are presented in table 2. the concentrations of elements, which are usually not incorporated in zircon, were either very near to the detection limit or clearly elevated and therefore ascribed to inclusions in zircon. 3.4.2. apatite chemical analysis through the process of zircon separation with sodium polytungstate, grains of apatite were also successfully separated due to their relatively high specific gravity. separated grains were used for chemical analysis of apatite, for which the same set of isotopes were monitored as for the chemical analyses of zircon. all elemental concentrations were calculated relative to p=18.25 wt. %, a value which is taken as a reference value in apatite, with the assumption that p is hardly replaced by some other elements in the apatite structure. therefore, the p concentration, derived from the isotope 31p, was set to 182,500 ppm. the calculated elemental concentrations are summarized in table 3. the figure 2. (a) columnar jointing of albite rhyolite at the rupnica geosite; person as scale; (b) plain-polarized transmitted-light photomicrograph of a typical microfabric of the rhyolite of rupnica taken from a thin section of the rupnica 3 sample; (c) backscattered electron image displaying the texture of the rhyolite of rupnica. the centre of the image shows an albite phenocryst. g eo lo gi a c ro at ic a geologia croatica 75/2256 ta bl e 3. c he m is tr y of a pa tit e fro m th e rh yo lit e of r up ni ca d et er m in ed b y la -ic pm s w ith c ha ra ct er is tic e le m en t r at io s a nd d et ec tio n lim its (d .l. ). el em en ta l m as s c on ce nt ra tio ns a nd d et ec tio n lim its a re g iv en in p pm . b .d .l. – b el ow d et ec tio n lim it. el em en t g ra in 1 g ra in 2 g ra in 3 g ra in 4 g ra in 5 g ra in 6 g ra in 7 g ra in 8 g ra in 9 g ra in 1 0 g ra in 1 1 d. l. m in m ax m ea n m ed ia n ba 4. 9 7. 0 5. 2 6. 8 5. 1 4. 0 4. 8 5. 8 6. 1 5. 9 7. 5 0. 49 4. 0 7. 5 5. 7 5. 8 ca 44 96 19 44 62 72 37 94 87 43 10 69 40 33 60 37 48 70 34 77 09 41 74 05 40 70 31 42 12 31 44 04 66 93 6 34 77 09 44 96 19 41 07 74 41 74 05 co b. d. l. 0. 31 0. 21 0. 25 0. 35 b. d. l. b. d. l. 0. 36 0. 66 0. 22 0. 20 0. 20 0. 20 0. 66 0. 32 0. 28 cr 3. 9 3. 0 2. 2 2. 3 2. 4 2. 4 4. 3 3. 1 4. 3 2. 8 3. 0 1. 9 2. 2 4. 3 3. 1 3. 0 fe 31 89 32 67 14 23 14 59 b. d. l. b. d. l. 65 25 84 42 7 b. d. l. 11 14 32 67 13 78 94 3 g a 11 17 17 12 6. 7 12 11 11 14 17 12 0. 35 6. 7 17 13 12 h f 0. 41 8. 1 0. 65 0. 24 0. 37 1. 5 b. d. l. 1. 1 2. 2 0. 83 0. 24 0. 22 0. 24 8 1. 6 0. 74 m n 75 0 84 4 89 2 85 1 79 3 10 22 72 1 81 7 10 66 10 16 80 1 1. 6 72 1 10 66 87 0 84 4 n b 1. 2 1. 1 0. 14 0. 09 12 0. 06 0. 10 0. 26 2. 0 5. 4 b. d. l. 0. 06 0. 06 12 2. 3 0. 70 p 18 25 00 18 25 00 18 25 00 18 25 00 18 25 00 18 25 00 18 25 00 18 25 00 18 25 00 18 25 00 18 25 00 12 5 18 25 00 18 25 00 18 25 00 18 25 00 pb 2. 5 3. 6 2. 1 2. 2 3. 6 1. 1 1. 7 1. 9 2. 3 3. 0 2. 0 0. 20 1. 1 3. 6 2. 4 2. 2 sc b. d. l. 2. 0 3. 5 1. 6 2. 5 2. 4 b. d. l. b. d. l. 2. 0 b. d. l. b. d. l. 1. 6 1. 6 3. 5 2. 3 2. 2 si 41 93 49 16 46 87 49 14 44 82 32 34 30 81 39 87 72 67 50 76 42 33 12 39 30 81 72 67 45 52 44 82 sn 1. 1 b. d. l. b. d. l. b. d. l. 2. 1 b. d. l. 1. 8 b. d. l. b. d. l. 1. 1 b. d. l. 0. 97 1. 1 2. 1 1. 5 1. 4 sr 38 6 38 2 37 9. 9 39 6 52 6 42 0 29 8 45 8 38 7 50 1 43 0 0. 09 29 8 52 6 41 5 39 6 ta 0. 04 0. 04 b. d. l. b. d. l. 0. 36 0. 05 b. d. l. b. d. l. 0. 07 0. 11 b. d. l. 0. 03 0. 04 0. 36 0. 11 0. 06 th 15 24 25 15 12 15 12 12 19 21 11 0. 07 11 25 16 15 ti 14 6 16 2 14 23 14 59 3. 6 b. d. l. 65 25 84 42 7 3. 3 3. 2 3. 3 25 84 48 9 10 5 u 5. 8 8. 5 9. 5 5. 7 4. 6 5. 9 5. 0 4. 9 8. 6 8. 0 3. 8 0. 09 3. 8 9. 5 6. 4 5. 8 v 3. 2 3. 5 0. 9 3. 3 5. 0 0. 3 3. 4 7. 6 8. 2 2. 4 7. 5 0. 21 0. 3 8. 2 4. 1 3. 4 y 10 29 16 17 13 46 10 19 69 3 95 1 95 4 98 0 11 72 15 30 10 52 0. 12 69 3 16 17 11 22 10 29 zn 5. 1 12 8. 1 10 9. 8 7. 1 5. 9 11 29 34 8. 3 2. 9 5. 1 34 13 10 zr 47 47 8 38 13 18 18 3 9. 1 42 17 4 57 12 0. 47 9. 1 47 8 97 42 la 76 6 12 65 12 76 89 1 53 9 85 4 71 7 76 7 11 94 12 31 96 9 0. 07 53 9 12 76 95 2 89 1 ce 17 50 30 89 29 01 22 58 13 39 21 34 17 93 18 05 27 72 29 09 21 49 0. 10 13 39 30 89 22 63 21 49 pr 23 1 45 0 37 9 32 5 19 6 28 2 24 6 26 3 35 6 40 3 27 5 0. 07 19 6 45 0 31 0 28 2 n d 11 39 19 21 19 01 15 82 96 2 14 17 12 54 12 54 17 91 21 06 12 29 0. 49 96 2 21 06 15 05 14 17 sm 27 1 49 5 44 4 34 4 25 1 37 5 31 3 31 1 41 4 52 8 29 8 0. 41 25 1 52 8 36 8 34 4 eu 34 49 43 45 56 53 32 41 44 54 41 0. 10 32 56 45 44 g d 28 4 45 8 41 3 33 4 28 8 32 5 27 1 30 9 40 3 42 8 32 0 0. 45 27 1 45 8 34 9 32 5 tb 41 59 68 44 39 42 40 45 57 63 47 0. 05 39 68 50 45 d y 21 6 35 7 41 9 27 0 20 7 20 9 22 2 21 2 34 6 35 5 25 4 0. 25 20 7 41 9 27 9 25 4 h o 42 63 75 50 38 36 47 40 66 66 48 0. 06 36 75 52 48 er 10 2 15 1 18 0 12 6 87 88 11 1 99 16 0 14 7 11 0 0. 12 87 18 0 12 4 11 1 tm 12 17 23 15 10 11 12 12 19 17 12 0. 04 10 23 15 12 yb 56 93 10 3 79 47 57 61 60 88 83 61 0. 28 47 10 3 72 61 lu 6. 9 11 12 10 5. 3 7. 6 6. 9 7. 5 11 10 8. 0 0. 06 5. 3 12 8. 7 8. 0 su m r ee 49 51 84 79 82 36 63 73 40 64 58 92 51 25 52 23 77 23 84 00 58 21 40 64 84 79 63 90 58 92 su m o xi de s ( w t % ) 10 6. 42 10 6. 27 96 .6 8 10 3. 98 10 0. 33 95 .7 7 91 .6 8 10 1. 84 10 1. 86 10 2. 83 10 5. 09 91 .6 8 10 6. 42 10 1. 16 10 1. 86 sr /y 0. 38 0. 24 0. 28 0. 39 0. 76 0. 44 0. 31 0. 47 0. 33 0. 33 0. 41 0. 24 0. 76 0. 39 0. 38 ce /c e* 1. 00 0. 99 1. 00 1. 01 0. 99 1. 05 1. 03 0. 97 1. 02 0. 99 1. 00 0. 97 1. 05 1. 01 1. 00 eu /e u* 0. 37 0. 31 0. 30 0. 41 0. 63 0. 47 0. 33 0. 41 0. 33 0. 35 0. 41 0. 30 0. 63 0. 39 0. 37 la n /y b n 9. 20 9. 15 8. 36 7. 65 7. 80 10 .0 9 7. 93 8. 65 9. 11 9. 95 10 .6 4 7. 65 10 .6 4 8. 96 9. 11 la n /s m n 1. 78 1. 61 1. 81 1. 63 1. 35 1. 43 1. 44 1. 55 1. 81 1. 47 2. 04 1. 35 2. 04 1. 63 1. 61 g d n /y b n 4. 08 3. 97 3. 24 3. 43 4. 99 4. 60 3. 59 4. 17 3. 68 4. 14 4. 20 3. 24 4. 99 4. 01 4. 08 la /s m 2. 8 2. 6 2. 9 2. 6 2. 1 2. 3 2. 3 2. 5 2. 9 2. 3 3. 2 2. 1 3. 2 2. 6 2. 6 y/ ʃr ee 0. 21 0. 19 0. 16 0. 16 0. 17 0. 16 0. 19 0. 19 0. 15 0. 18 0. 18 0. 15 0. 21 0. 18 0. 18 c e /t h 11 5 13 1 11 8 15 1 11 0 14 3 15 5 15 2 14 3 14 0 20 2 11 0 20 2 14 2 14 3 g eologia c roatica schneider et al.: dating and geochemistry of zircon and apatite from rhyolite at the unesco geosite rupnica (mt. papuk, northern croatia) ... 257 concentrations of elements, which are usually not incorporated in apatite (such as co, cr, ni, sc, sn, ta and v) were either only slightly above or below the detection limit. 3.4.3. zicon age-dating for zircon dating and isotopic corrections with la-icp-ms, 3 natural zircon reference materials were used: fc1 (1099.0±0.6 ma; paces & miller, 1993), peixe (564±4 ma; dickinson & gehrels, 2003 and 558±2.7 ma; shaulis et al., 2010), and plešovice (337.13±0.37 ma; sláma et al., 2008). the following ions were measured: 202hg, 204(hg+pb), 206pb, 207pb, 208pb, 232th, 235u, 238u, and 254(238u16o). the method and corrections used for data evaluation are described in detail in balen et al. (2020). by dating these 3 references as unknowns, using the aforementioned method and corrections, the obtained concordia ages plotted in a 206pb/238u vs. 207pb/235u diagram (fc1=1104.3±5.9 ma, mswd=0.5, n=8; peixe=564.8±4.1 ma, mswd=0.2, n=6; plešovice=335.6±3.7 ma, mswd=0.2, n=4) coincide with their literature values. 4. results 4.1. outcrop and rock description the rupnica locality is a small abandoned quarry in the northwestern part of mt. papuk within the papuk nature park. it is a key geosite of the papuk geopark protected under the unesco supervision, and is well-known for its columnar jointing developed in albite rhyolite (fig. 2a). the site is located near the town of voćin (fig. 1c, coordinates: 45.6049º n, 17.5320º e). balen & petrinec (2014) investigated the phenomenon of columnar jointing in detail, conducting a non-destructive statistical analysis of the geometric distribution of columns combined with petrography, geochemistry and the geology of the geosite. these authors suggested that the albite rhyolite formed via rapid cooling of a (sub)surface acidic lava body. the albite rhyolite of the rupnica locality and its variations (aegirine-albite and anorthoclase-aegirine rhyolite) are described as volcanic rocks, the chemical composition of which are not significantly affected by hydrothermal alteration or other types of figure 3. comparison of the rhyolite of rupnica, mt. požeška gora granite and acidic effusive rocks from the northern part of mt. kozara: (a) qap modal composition diagram after streckeisen (1974, 1978) for both volcanic and plutonic rocks: q – quartz; a – alkali feldspar; p – plagioclase; 2 – alkali-feldspar trachyte/q-rich granite; 3 – alkali-feldspar rhyolite/alkali-feldspar granite; 4 – rhyolite/syenogranite; 8 – q-alkali-feldspar trachyte/q-alkali-feldspar syenite. classification and discrimination diagrams based on major elements after (b) de la roche et al. (1980), and (c–e) frost et al. (2001) and frost & frost (2011). geochemical data for the acidic effusive rocks from the northern part of mt. kozara are from ustaszewski et al. (2009) and cvetković et al. (2014). g eo lo gi a c ro at ic a geologia croatica 75/2258 secondary processes (tajder, 1956, 1960). the rhyolites are leucocratic and light-grey to greenish in colour with porphyritic texture and phenocrysts of feldspar (albite). detailed petrographic descriptions of albite rhyolite and its variations can be found in tajder (1956, 1960) and balen & petrinec (2014). albite contains 98.1−99.9 % albite component (balen & petrinec, 2014) and occurs as phenocrysts (up to 30 vol. % of the rock) and as microliths in the fine-grained groundmass (fig. 2b−c) together with a devitrified volcanic glass (up to 10 vol. %). magnetite, apatite, zircon and in places alkali clinopyroxene (aegirine-augite) occur as accessory minerals, while kaolinite, illite, smectite, chlorite and calcite are secondary minerals. haematite, apatite and anatase are found additionally as inclusions in zircon (see section 4.3.2. inclusions in zircon). 4.2. whole-rock geochemistry the rhyolite of rupnica (table 1, fig. 3) is characterized by: (1) relatively high siliceous compositions (sio2 up to 69.5 wt. %), (2) high abundance of alkalies (k2o+na2o between 8.2 and 9.0 wt. % with k2o up to 3.5 wt. %), (3) relatively high k2o/na2o molar ratios (0.36–0.43), (4) high al2o3 (15.4–16.7 wt. %, molar a/cnk ratios = al2o3/(cao+na2o+k2o) of 1.08–1.24, a/nk ratios = al2o3/(na2o+k2o) of 1.24–1.32), (5) low cao (0.35–1.5 wt. %), mgo (0.27–0.53 wt. %), and mno (<0.07 wt. %), and (6) relatively high fe2o3 contents (3.5–4.2 wt. %); thus, the feot/ (feot+mgo) ratios (0.87–0.92) are high. these parameters indicate that the studied rocks are peraluminous, ferroan and alkalicalcic to alkalic (fig. 3c–e). in the primitive mantle-normalized element plot (fig. 4a), the analysed rhyolite samples display positive anomalies of k, pb, and zr and relatively pronounced negative anomalies of p, ba, eu, nb and ti. chondrite-normalized data of ree reveal an enrichment of light ree (lree) relative to heavy ree (hree) with (la/yb)n, (la/sm)n and (gd/yb)n of 3.47–5.92, 2.76–3.64, and 1.20–1.40, respectively (fig. 4b). eu/eu* parameters are between 0.66 and 0.74, whereas ce/ce* ranges between 0.96 and 1.33. the sum of ree is around 142 ppm. contents of y and yb are around 32 ppm and 3.5 ppm, respectively. the data presented for the major elements are in the good agreement with previous data from tajder (1956, 1960) and pamić (1991) for rhyolite of rupnica. 4.3. accessory minerals analyses 4.3.1. zircon external morphology the population of zircon analysed for external morphology consists of 65 grains which are 50‒110 μm long and 25‒55 μm wide. aspect ratios range from 1.4:1 to 3.3:1, with the median value of 2.3:1. such ratios, the colourlessness, high transparency and birefringence are usually characteristic of early crystallized zircon in a granitic magma (hoskin & schaltegger, 2003). around 40 % of the examined zircon population is partially dissolved, so the external morphology could not always be clearly defined. the rest of the separated zircon, i.e. grains with recognizable external morphology, was carefully examined. their external morphology is defined by {100} prisms and {101} > {211} bipyramids. after pupin’s (1980) zircon typology, types j4 (50 %), j3 (30 %), j5 (10 %) and j2 (<10 %) are present (fig. 5). according to pupin & turco (1972) and pupin (1980), such morphologies are considered to characterize zircon crystallized from high-temperature magmas with lower crust or upper mantle origin. 4.3.2. inclusions in zircon zircon grains are very rich in inclusions. even dozens of them can occur in a single zircon grain and therefore represent potential material for further detail research. the inclusions vary in shape; some of them are euhedral and needle-like, but all are smaller than 10 μm. raman bands of zircon (at 202, 212, 225, 356, 392, 438, 972–974 and 1005–1008 cm−1, strongest at 356, 972–974 and 1005–1008 cm−1, after frezzotti et al., 2012), despite the confocal mode, are very intense, making the identification of included phases difficult. so far, inclusions of haematite (bands at 223, 290, 409, 498, 609 and 1313 cm−1, strongest at 290 and 409 cm−1, after frezzotti et al., 2012), apatite (bands at 432, 449, 581, 592, 608, 965, 1042, 1053 and 1081 cm−1, strongest at 965 cm−1; characteristic for f-apatite after hurai et al., 2015; bands at 3100– 3800 cm−1 characteristic for o-h were not detected) and anatase (143, 195, 395, 514 and 638 cm−1, strongest at 143 and 638 cm−1, after frezzotti et al., 2012) were detected (fig. 6). 4.3.3. zircon geochemistry for zircon geochemistry, 14 grains were successfully analysed with la-icp-ms. the results, together with basic statistical parameters and characteristic elemental ratios, are presented in table 2. zircon from the rhyolite of rupnica shows variable figure 4. comparison of the rhyolite of rupnica, mt. požeška gora granite and rhyolite from the northern part of mt. kozara: (a) primitive mantle whole-rock incompatible trace element patterns after sun & mcdonough (1989) and (b) whole-rock chondrite-normalized patterns of ree after boynton (1984). references for mt. kozara are the same as in fig. 3. g eologia c roatica schneider et al.: dating and geochemistry of zircon and apatite from rhyolite at the unesco geosite rupnica (mt. papuk, northern croatia) ... 259 u (137–958, mean 443 ppm) and th (107–1411, mean 531 ppm) contents, with th/u ratios between 0.78 and 1.62 (mean 1.13), typical for igneous zircon (hoskin & schaltegger, 2003; kirkland et al., 2015). the compositional range of the determined ree patterns (fig. 7a) is characteristic for zircon from granitoids (belousova et al., 2002a; hoskin & schaltegger, 2003) with significant rise of contents from sm to lu and total contents of ree between 1155 and 4490 ppm (mean 2993 ppm). a positive ce anomaly (mean 1.27) indicates oxidized magma conditions, as does the finding of haematite as a primary inclusion in zircon. 4.3.4. zircon u-th-pb dating the results of dating on 20 zircon grains from the rupnica locality, selected on the basis of euhedral shape and elemental ratios (such as th/u), are presented in table 4 and in a concordia diagram in fig. 8. zircon yielded a concordia age of 80.8±1.8 (2σ) ma and a mean square weighted deviation (mswd) of 0.8. the zircon ages determined from the individual calibrated quotients of isotopic intensities 206pb/238u, 207pb/235u and 208pb/232th are 80.0±2.1, 82.7±3.3 and 81.7±1.8 ma, respectively, with errors given as 2σ values. the mswd values of 0.76, 0.45 and 1.00, respectively, suggest a single zircon generation. table 4. individual elemental and isotopic concentrations and ages of zircon from the rhyolite of rupnica obtained from calibrated isotopic ratios of 206pb/238u, 207pb/235u, and 208pb/232th. elemental concentrations of pb refer to the sum of the pb isotopes. grain elemental concentrations isotopic concentrations (ppm) si (wt. %) zr (wt. %) th (ppm) u (ppm) pb (ppm) th/u 204pb 206pb 207pb 208pb 1b 15.14000 47.13930 495.67 492.20 7.64 1.01 0.004 5.13 0.36 2.14 2b 15.14000 42.77307 328.12 343.58 7.41 0.96 0.024 4.39 0.60 2.40 3b 15.14000 46.23996 785.15 667.36 12.81 1.18 0.034 8.07 0.78 3.93 4b 15.14000 44.05930 221.57 279.74 4.89 0.79 0.052 3.28 0.30 1.26 5b 15.14000 43.30943 825.65 696.89 14.78 1.18 0.033 8.75 1.11 4.89 6b 15.14000 44.56110 404.35 517.83 9.19 0.78 0.013 6.50 0.55 2.12 7b 15.14000 43.86399 444.66 443.50 8.04 1.00 0.005 5.56 0.41 2.05 8b 15.14000 47.62453 770.86 705.22 13.30 1.09 0.001 9.00 0.66 3.65 9b 15.14000 48.44948 1552.14 917.59 18.77 1.69 0.012 12.21 0.70 5.85 10b 15.14000 45.80696 525.60 493.64 8.70 1.06 0.000 5.98 0.44 2.28 11b 15.14000 45.34541 828.67 684.20 11.90 1.21 0.017 8.40 0.41 3.08 12b 15.14000 44.69870 785.57 659.58 14.01 1.19 0.018 9.02 0.90 4.07 13b 15.14000 50.44010 524.08 476.65 10.30 1.10 0.058 6.30 0.79 3.15 14b 15.14000 48.10264 458.37 448.63 7.66 1.02 0.022 5.11 0.44 2.09 15b 15.14000 48.20173 964.95 718.38 13.46 1.34 0.023 8.23 0.82 4.38 16b 15.14000 43.88730 2157.05 1263.47 24.03 1.71 0.010 15.30 0.83 7.88 17b 15.14000 49.07538 386.88 281.20 5.82 1.38 0.026 3.62 0.34 1.83 18b 15.14000 49.54529 933.63 691.47 14.00 1.35 0.014 8.30 0.80 4.89 19b 15.14000 49.07977 396.54 360.44 7.04 1.10 0.016 4.73 0.42 1.87 20b 15.14000 48.50643 419.63 426.19 7.52 0.98 0.019 5.01 0.38 2.12 grain isotopic ratios age (ma) 206pb/238u 1σ 207pb/235u 1σ 208pb/232th 1σ 206pb/238u 1σ 207pb/235u 1σ 208pb/232th 1σ 1b 0.01160 0.00061 0.07659 0.00536 0.00421 0.00018 74.3 3.9 74.9 5.1 85.1 3.6 2b 0.01214 0.00063 0.08326 0.02146 0.00449 0.00066 77.8 4.0 81.2 20.1 90.9 13.3 3b 0.01228 0.00069 0.08622 0.01491 0.00410 0.00019 78.7 4.4 84.0 13.9 82.8 3.9 4b 0.01185 0.00041 0.07631 0.01193 0.00433 0.00041 75.9 2.6 74.7 11.3 87.6 8.3 5b 0.01221 0.00100 0.08209 0.01861 0.00412 0.00027 78.2 6.4 80.1 17.5 83.3 5.4 6b 0.01287 0.00132 0.08643 0.01170 0.00404 0.00018 82.4 8.4 84.2 10.9 81.7 3.6 7b 0.01310 0.00088 0.08697 0.00913 0.00407 0.00019 83.9 5.6 84.7 8.5 82.3 3.9 8b 0.01296 0.00087 0.09118 0.01000 0.00429 0.00012 83.0 5.6 88.6 9.3 86.7 2.5 9b 0.01383 0.00095 0.09191 0.00627 0.00385 0.00011 88.6 6.1 89.3 5.8 78.0 2.3 10b 0.01243 0.00042 0.08519 0.00735 0.00385 0.00020 79.6 2.7 83.0 6.9 77.8 4.1 11b 0.01319 0.00081 0.08792 0.00330 0.00397 0.00023 84.5 5.1 85.6 3.1 80.4 4.7 12b 0.01366 0.00109 0.09348 0.02380 0.00399 0.00054 87.5 6.9 90.7 22.1 80.7 10.9 13b 0.01332 0.00086 0.08398 0.01203 0.00393 0.00020 85.3 5.5 81.9 11.3 79.5 4.0 14b 0.01147 0.00124 0.07905 0.01466 0.00373 0.00028 73.5 7.9 77.3 13.8 75.6 5.7 15b 0.01178 0.00182 0.07547 0.01261 0.00368 0.00026 75.5 11.6 73.9 11.9 74.4 5.2 16b 0.01294 0.00101 0.08967 0.00631 0.00390 0.00017 82.9 6.4 87.2 5.9 78.9 3.4 17b 0.01322 0.00092 0.08653 0.01349 0.00392 0.00023 84.7 5.9 84.3 12.6 79.2 4.6 18b 0.01277 0.00073 0.08081 0.00622 0.00434 0.00015 81.8 4.6 78.9 5.8 87.7 3.1 19b 0.01351 0.00071 0.08925 0.01587 0.00372 0.00027 86.5 4.5 86.8 14.8 75.3 5.4 20b 0.01192 0.00069 0.07766 0.00590 0.00420 0.00024 76.4 4.4 75.9 5.6 84.9 4.9 weighted average (ma) 80.0 82.7 81.7 error 2σ (ma) 2.1 3.3 1.8 mswd 0.76 0.45 1.00 g eo lo gi a c ro at ic a geologia croatica 75/2260 4.3.5. apatite geochemistry for apatite geochemistry, 11 grains were successfully analysed with la-icp-ms (table 3). ree patterns (fig. 7b) with total contents of ree between 4064 and 8479 ppm (mean 6390 ppm) display a negative slope according to the relative enrichment of the lree, with a (la/yb)n mean ratio of 9.0, which is typical for apatite from granitoids (belousova et al., 2002b). pronounced negative eu anomalies with a mean of 0.39 were determined. this mean is close to the average for apatite from granitoid rock types (belousova et al., 2002b). 4.4. geothermometry a zircon saturation temperature (zst) was calculated after watson & harrison (1983) and gervasoni et al. (2016), using whole-rock zr concentrations (table 1). a negative sio2-zr covariation occurs in the whole-rock data for the rhyolite of rupnica. therefore, zrsio4 saturation during early magmatic crystallization is assumed (schiller & finger, 2019). calculated temperatures are within a narrow range of 858‒867 ºc (mean 863 ºc) using parameters from watson & harrison (1983), indicating a high-temperature environment. calculations with the model by gervasoni et al. (2016), which is considered to give more reliable values, yielded lower temperatures of 778‒798 ºc (mean 789 ºc), but these would still correspond to a high-temperature environment. the ti-in-zircon temperature after watson et al. (2006) was calculated for selected grains that are characterized by relatively low ti contents, i.e. analyses that exclude ti-rich inclusions (table 2). calculated temperatures are 801‒831 ºc (mean 814 ºc) with a precision of ±5 ºc (watson et al., 2006). these temperatures fit the range of the calculated zst and are only slightly lower than the zst after watson & harrison (1983). such a temperature difference is common for samples with m (cation ratio) = (na+k+2ca)/al·si <1.9 (fu et al., 2008; fig. 9). the apatite saturation temperature (ast) calculated after harrison & watson (1984) for metaluminous to slightly peraluminous systems is 900 ºc. as apatite generally crystallizes over a relatively restricted interval within 60‒100 ºc of the ast (piccoli & candela, 1994, 2002), the calculated ast would imply crystallization of apatite prior to crystallization of zircon (corroborated by apatite inclusions in zircon) or during zircon crystallization. because zst and ast are based on the wholerock analysis and not on glass separates, the calculated temperatures are considered to represent maximum ones (kirkland et al., 2015). 5. discussion 5.1. whole-rock geochemistry and comparison with an a-type granite at mt. požeška gora the whole-rock geochemistry in this paper was intended to provide the geochemical environment for zircon and apatite crystallization in the studied rocks. however, whole-rock geochemistry presented here shows noticeable similarities with the a-type granite of mt. požeška gora, despite the limited number of analysed samples. pamić (1997) associated the voćin volcanic rocks with those at mt. požeška gora. it was assumed that (sub-)volcanic rocks from both localities have a similar age and are therefore associated to a unique senonian basalt-rhyolite formation, although the volcanic rocks at mt. požeška gora also comprise a-type granite. pamić (1997) suggested a connection of these masses figure 5. (a) typical external morphologies of zircon from the rhyolite of rupnica. (b) morphologies and types of investigated zircon grains shown on the modified zircon typology diagram after pupin (1980). g eologia c roatica schneider et al.: dating and geochemistry of zircon and apatite from rhyolite at the unesco geosite rupnica (mt. papuk, northern croatia) ... 261 and a late cretaceous age based on petrography, geochemistry and mineralogical features of the samples. in addition, the rather arguable age data of k-ar dating on basalts from voćin (72.8‒51.7 ma; pamić, 1991) and the application of the rb-sr isochron method to granite and rhyolite from mt. požeška gora (71.5±2.8 ma; pamić et al., 1988) were used to support this connection. the latter age was recently revised by la-icp-ms dating of zircon to 83.6±1.5 ma by balen et al. (2020). the zircon age fits geological relations to the surrounding sedimentary rocks. when comparing mean values of whole-rock major element contents of granite from mt. požeška gora (balen et al., 2020, pamić, 1987) and rhyolite of rupnica (table 1), the following similar mean values were found: (1) highly siliceous compositions (69.9 and 67.75 wt. % sio2, respectively); (2) enrichment in alkalies (k2o+na2o content: 8.68 and 8.60 wt. %); (3) relatively high k2o/na2o molar ratios (0.56 and 0.40); (4) high al2o3 contents (15.3 and 15.8 wt. % al2o3; a/cnk ratio = 1.21 and 1.19; a/nk ratio = 1.27 and 1.28); (5) low contents of cao (0.28 and figure 6. (a) plain-polarized transmitted-light photomicrograph of a zircon grain rich in inclusions. arrows indicate the analytical spots for raman spectrometry and detected inclusions. magnification 1000x. ap – apatite; ats – anatase; hem – haematite. (b) raman spectra of anatase, apatite and haematite inclusions in zircon. spectra were compared with data given by frezzotti et al. (2012) and hurai et al. (2015). g eo lo gi a c ro at ic a geologia croatica 75/2262 0.64 wt. %), mgo (0.07 and 0.42 wt. %), and mno (<0.08 wt. %); (6) relatively high fe2o3 contents (3.30 and 3.84 wt. %); (7) high feot/(feot+mgo) ratios (0.98 and 0.89). according to the listed parameters, both the mt. požeška gora granite and the rhyolite of rupnica refer to peraluminous, oxidized, ferroan, and alkalicalcic to alkalic magmas (fig. 3c–e). trace element contents in both the granite from mt. požeška gora (balen et al., 2020) and the rhyolite of rupnica are also similar (fig. 4). in the primitive mantle-normalized element plots (fig. 4a) both rock types display positive anomalies of k, pb, and zr and relatively pronounced negative anomalies of high field strength elements (hfse), p, ba and eu. the main differences concern the contents of cs, u and th. whole-rock zr/hf ratios are also similar (mean: 39 for granite and 42 for rhyolite) and fall in the range for the average continental crust (pupin, 2000). chondrite-normalized data of ree (fig. 4b) reveal an enrichment of lree relative to hree with pronounced negative eu anomalies (mean: 0.46 for granite and 0.71 for rhyolite) and minor positive ce anomalies (mean: 1.01 for granite and 1.08 for rhyolite). the mean sum of ree is 165 ppm for the granite and 142 ppm for the rhyolite. ree patterns of the rhyolite of rupnica do not show the tetrad effect implying the absence of a significant h2o content in the melt (mclennan, 1994). instead, according to the zr/hf (39–43) and y/ho (25–28) ratios, the element distribution is charac (charge and radius controlled, bau, 1996). patfigure 7. (a) chondrite-normalized patterns of ree in (a) zircon and (b) apatite grains separated from the rhyolite of rupnica using normalizing factors after boynton (1984). result of the whole-rock (wr) analysis of sample rupnica 3, from which zircon and apatite grains were separated (thick line), is given for comparison. (c) hfo2 versus y2o3 diagram after pupin (2000). fields 1–2 are specific domains for anorogenic rocks, fields 5–6: orogenic rocks, fields 3–4 both types of rocks.1b – hypersolvus alkaline granite/rhyolite; 1d – hypersolvus alkaline granite/rhyolite or silica over/under-saturated alkaline/peralkaline syenite/trachyte; 2 – subsolvus alkaline granite/rhyolite. for other fields see the reference. (d) chondrite-normalized patterns of ree after boynton (1984); comparison of zircon grains from mt. požeška gora granite and the rhyolite of rupnica. figure 8. u-pb concordia diagram for zircon from the rhyolite of rupnica. error ellipses relate to 1σ errors. weighted average ages, errors and mswd values are given in table 4. figure 9. boxplot of temperature ranges for different geothermometers: 1 – apatite saturation temperature (ast) after harrison & watson (1984); 2 – zircon saturation temperature (zst) after watson & harrison (1983); 3 – ti-in-zircon after watson et al. (2006); 4 – zst after gervasoni et al. (2016). g eologia c roatica schneider et al.: dating and geochemistry of zircon and apatite from rhyolite at the unesco geosite rupnica (mt. papuk, northern croatia) ... 263 terns of incompatible trace elements (fig. 4a and 4b), trace element ratios (table 1), apparent enrichments in lree together with intermediate-to-low contents of hfse (except hf and zr), variable abundances of large ion lithophile elements (lile), and negative eu anomalies (fig. 4b) point to crustal sources of the corresponding magmas. according to the geochemistry in respect to reference materials (boynton 1984; sun & mcdonough,1989), standard geotectonic classification diagrams and classification of granitic rocks by whalen et al. (1987), eby (1990, 1992) and king et al. (1997), the rhyolite of rupnica shows a-type features (figs. 10 and 11), which are relatively high contents of hfse (ga, nb, ta, th, u, y, zr); significantly enriched lile compared to primitive mantle, high feo* (>1 wt. %), k and total contents of ree, 10000 × ga/al ratios of 2.0−2.5, and low mgo, cao, cr, ni, sr and ba contents. furthermore, the temperature characteristics for magmas forming the albite rhyolite of rupnica and the granite of mt. požeška gora are similar. both rocks originated from hot (ca. 800–900 ºc), dry and oxidized magmas generated at lowerto mid-crustal levels. an inhomogeneous source at such depth can be expected (kempton et al., 1990; burov et al. 2007), where tonalitic to granodioritic crust produces peraluminous alkali-calcic to calc–alkalic granitic melts (patiño douce 1997; frost & frost, 2011) by a low degree of partial melting at higher pressures (see skjerlie & johnston, 1993, for magnesian tonalite at pressures ≥ 10 kbar). a relatively fast ascent to (sub)surface levels of the a-type magma led to rhyolite with glass in the matrix at rupnica. 5.2. chemical compositions of zircon and apatite and their petrogenetic significance normalized patterns of ree in zircon, not contaminated by inclusions, demonstrate the igneous nature by negative eu anomalies and enrichment of hree (fig. 7a) with generally high sums figure 10. diagrams to discriminate a-type granitoids after whalen et al. (1987). i, s, and a denote i-, s-, and a-type granites, respectively. fg – fractionated felsic granites; otg – unfractionated m-, i-, and s-type granites. figure 11. (a) geotectonic discrimination diagram after batchelor & bowden (1985), (b) geotectonic discrimination diagrams for granites after pearce et al. (1984) and pearce (1996) and (c) after harris et al. (1986). vag – volcanic arc granites, wpg – within-plate granites, syn-colg – syn-collision granites, org – ocean-ridge granites, post-colg – post-collision granites, gcts – granites from collisional tectonic setting. g eo lo gi a c ro at ic a geologia croatica 75/2264 of ree. the positive ce and significantly negative eu anomalies are typical for zircon from granitoids especially for those with 65‒70 wt. % of sio2 (belousova et al., 2002a). a less developed eu anomaly accompanied by an enhanced hf content in zircon indicates co-crystallization of zircon and plagioclase (słodczyk et al., 2016). relative enrichment in hree over medium ree and apatite and a ti-phase detected by raman spectroscopy as inclusions in zircon suggest the co-crystallization of these phases (hoskin et al., 2000). in the rupnica samples, apatite also occurs as individual grains, which combined with ast values point to early crystallization of the apatite prior to or simultaneous with zircon. chemical compositions of zircon (e.g. hf, th, u) define it as an early crystallized mineral formed in a deep magma chamber at relatively high and constant temperatures (wang et al., 2010; kirkland et al., 2015). according to wang et al. (2010), an early-stage zircon is characterized by high zr/hf ratios (~39; compared to late-stage zircon ~29) and low hf concentrations (~1.35 wt. % hfo2 compared to 1.85 wt. % for the late-stage), which fit the chemistry of the studied zircon (mean zr/hf=55, hfo2=1.04 wt. %). zircon of rupnica has hf concentrations of 6436‒11511 ppm (mean 8784 ppm), which are characteristic of highly-evolved magmas (belousova et al., 2002a). according to pupin (2000), whole-rock and zircon zr/hf ratios are indicative of magmatic fractionation of a granitic melt. a decrease of these ratios in zircon from mantle-derived plagiogranites (median 60−70), through hypersolvus alkali granites, alkali syenites and hybrid calc-alkaline granitoids to the lowest values in peraluminous granites and migmatites (median 35−37) was noted by pupin (2000). in other words, the higher this ratio the higher is the mantle input in the generated magma. for the studied zircon, the zr/hf ratio is on ave rage 55, which points to a chemical mantle contribution to the magma. this view is supported by balen et al. (2020) who suggested a potential influence from a mantle source on the magma forming the a-type granite of mt. požeška gora based on zr/hf ratio, morphology of zircon and inclusions therein. furthermore, the zr/hf ratio of zircon crystallizing from a water-undersaturated melt is higher than the whole-rock zr/hf ratio (erdmann et al., 2013; breiter & škoda, 2017), which is valid for the rhyolite of rupnica (mean whole-rock zr/hf ratio = 42). zircon grains extracted from the mt. požeška gora granite and the rhyolite of rupnica also show similar geochemical signatures (fig. 7d) with mean zircon zr/hf ratios of 55 and 53, respectively, and th/u ratios of 0.74 and 1.13, respectively. these signatures point to a magma origin by partial melting of material from midto lower-crustal levels (hoskin & schaltegger, 2003). the high-temperature environment determined here by zst, ti-in-zircon and ast (789–863, 814 and 900 °c, respectively) was also found for the early crystallization of the studied accessory minerals in the mt. požeška gora granite (balen et al., 2020) with zst of 830‒950 ⁰c (mean 873 ⁰c). furthermore, zircon morphologies after pupin (1980) with d and j5 type prevailing in mt. požeška gora granite and j4 and j3 in the rhyolite of rupnica also suggest a high-temperature environment which is typical for an iand/or an a-type granitic melt. zircon crystallized from a magma which originated in the lower crust, but contributions from an upper mantle source should not be excluded due to the external zircon morphology (pupin & turco, 1972; pupin, 1980) and zircon zr/hf ratios (pupin, 2000). this crystallization occurred in a deep magma chamber at relatively constant temperature > 800 ⁰c (wang et al., 2010; kirkland et al., 2015). the amplitude of eu anomalies in apatite generally increases toward more fractionated rocks and is controlled by the crystallization of feldspar (belousova et al., 2002b). contents of mn are expected to be relatively high in apatite crystallized from a magma under reduced conditions (belousova et al., 2002b, reported mn contents of 0.1–1 wt. %). moreover, belousova et al. (2002b) demonstrated that there is an excellent correlation between contents of ree in apatite and the oxidation state of the magma. apatite from more oxidized granitic melts shows lower y/ʃree and higher la/sm and ce/th ratios than apatite from less oxidized rocks, regardless of the overall degree of fractionation of the magma following such relations, the apatite from rupnica with y/ʃree= 0.18, la/sm=2.6 and ce/th=142 crystallized in an oxidizing environment. this environment is also confirmed by primary inclusions of haematite in zircon from the rhyolite of rupnica and the red granite from mt. požeška gora (balen et al., 2020). 5.3. implications on the regional setting considering the afore-mentioned characteristics of the whole rock and the accessory minerals therein, it can be assumed that the magmas forming the mt. požeška gora granite and the rhyolite of rupnica have the same origin. thus, the rhyolite of rupnica should be considered as a part of an igneous suite that intruded not only the sava zone, but also the adjacent tisia mega-unit. this also concerns the mt. požeška gora granite together with the mt. prosara leucogranite (82.68±0.13 ma; pamić & injuk, 1988; pamić & lanphere, 1991b; ustaszewski et al., 2009) and late cretaceous acidic rocks from mt. moslavačka gora (82±1 ma; starijaš et al., 2010; balen & broska, 2011; balen & petrinec, 2011), but also basic rocks from the latter locality which show upper mantle isotopic signatures (109±8 and 83±9 ma; balen et al., 2003). also rhyolites from the northern part of mt. kozara (ustaszewski et al., 2009; cvetković et al., 2014), located in northern bosnia and herzegovina south of the slavonian mts. (figs. 1 and 3), can be included in the comparison. these rhyolites with a mean zircon 206pb/238u age of 81.60±0.12 ma (ustaszewski et al., 2009) are part of a bimodal magmatic association. mafic rocks of the same age occur and, according to geochemistry (normalized patterns of ree), originated from the same magma source as the acidic rocks. ustaszewski et al. (2009) placed these rocks into an intra-oceanic environment (island-arc, ocean island or mid-ocean ridge setting), based on sr and nd isotopes. cvetković et al. (2014) focused more on the acidic rocks of the bimodal association from the northern part of mt. kozara and confirmed the close petrogenetic link between basic and acidic rocks. furthermore, these authors revisited the basic suite and concluded that the entire ophiolite slice from the northern part of mt. kozara could represent the remnant of an anomalous ridge segment (similar to present day iceland). cogenetic acidic magmas most probably originated through the obduction-induced partial melting of hydrated oceanic crust. these voluminous magmas were emplaced as subaerial high-temperature rhyodacite-rhyolite. discrimination diagrams after batchelor & bowden (1985) place rhyolites from the northern part of mt. kozara together with the rhyolite of rupnica and the mt. požeška gora granite in an anorogenic or postorogenic environment, whereas rhyodacites from mt. kozara point to a somewhat different environment (fig. 11a). rhyolite of rupnica and the mt. požeška g eologia c roatica schneider et al.: dating and geochemistry of zircon and apatite from rhyolite at the unesco geosite rupnica (mt. papuk, northern croatia) ... 265 gora granite plot into the within plate or, less clearly, into the volcanic arc field (fig. 11b) of the discrimination diagrams after pearce et al. (1984), whereas the rhyolite of rupnica can be discriminated from the mt. požeška gora granite (within-plate setting vs. volcanic arc setting, fig. 11c) in the rb-hf-ta diagram by harris et al. (1986). according to hfo2 vs. y2o3 contents (7590‒13574 ppm hfo2, mean 10372 ppm; 1495‒7815 ppm y2o3, mean 5033 ppm), which are directly connected to the contrasting hf and y contents in zircon of orogenic and anorogenic rocks (pupin, 2000), zircon from the rhyolite of rupnica crystallized from a hypersolvus or subsolvus alkaline granitic magma of anorogenic origin (fig. 7c). according to the data presented here and those by balen et al. (2020) discussed above, the rhyolite of rupnica with a zircon u-pb age of 81 ma is related to the magmatism within the sava zone, i.e. the collisional environment between the adria and tisia microplates, and in the adjacent tisia mega-unit. this collision with adria as a subducted plate caused hot mantle to rise, leading to local extensional rift processes in the suture zone. the subsequent crustal extension caused a fast extrusion of rhyolitic magmas to the (sub)surface. the igneous rocks of the banatitic magmatic and metallogenetic belt (bmmb, berza et al., 1998) of late cretaceous age (zimmerman et al., 2008; overview in ilinca et al., 2011), known as banatites, extend to the balkan-south carpathian orogenic belt in southeastern europe. although the petrology of the banatites is extremely diverse, geochemical data (trace elements and isotope composition) point to subduction related magmas with sources in the upper mantle or even lower crust (ilinca et al., 2011). for the formation of the bmmb a slab rollback model is plausible (zimmerman et al., 2008). the rhyolite of rupnica and the mt. požeška gora granite share their age with those of banatites and therefore could represent the westernmost occurrences of the bmmb, as has been previously suggested by ilinca et al. (2011). this opens a new link and possible extension of research in the future, because the relationship between the bmmb and the igneous rocks, which penetrated the sava zone and tisia mega-unit in the south-western part of the panonnian basin, is currently far from clear. 6. conclusion the chemical compositions of zircon, apatite, and whole-rock, as well as the petrography of the rhyolite of rupnica indicate that the magma forming this rock originated from partial melting of midto lower-continental crust at temperatures > 800 °c. the compressional tectonics of the adria microplate towards europe and the closure of the neotethys ocean caused the opening of local extensional zones. in such a tectonic environment, the magmas of the rhyolite of rupnica were generated. these local extensional zones acted as pathways for the rapid ascent of hot, dry, and oxidized acidic magmas to (sub)surface levels in the late cretaceous at ca. 81 ma. the rhyolite of rupnica and the granite from mt. požeška gora have similar geochemical characteristics; both rocks formed contemporaneously from peraluminous, ferroan, alkali-calcic to alkalic a-type magmas of the same origin. the cretaceous (ca. 81 ma) magmas intruded the sava zone and the adjacent tisia mega-unit. acknowledgment the authors are grateful to jarmila luptakova () for her help with raman spectroscopy. the support with logistics provided by the papuk nature park and goran radonić is greatly appreciated. our gratitude goes to ralf schuster and vladica cvetković for their constructive comments and vesnica garašić for editorial handling. support by the croatian science foundation (ip 2014-09-9541) is acknowledged. references balen, d. & broska, i. (2011): tourmaline nodules: products of devolatilization within the final evolutionary stage of granitic melt?– geol. soc. london spec. publ., 350, 53–68. doi: 10.1144/sp350.4 balen, d. & petrinec, z. (2011): contrasting tourmaline types from peraluminous granites: a case study from moslavačka gora (croatia).– mineral. petrol., 102, 117–134. doi: 10.1007/s00710-011-0164-8 balen, d. & petrinec, z. (2014): development of columnar jointing in albite rhyolite in a rapidly cooling volcanic environment (rupnica, papuk geopark, croatia).– terra nova, 26, 102–110. doi: 10.1111/ter.12075 balen, d., schuster, r., garašić, v. & majer, v. (2003): the kamenjača olivine gabbro from moslavačka gora (south tisia, croatia).– rad hrvatske akademije znanosti i umjetnosti, 486, 27, 57–76. balen, d., horvath, p., tomljenović, b., finger, f., humer, b., pamić, j. & arkai, p. (2006): a record of pre-variscan barrovian regional metamorphism in the eastern part of the slavonian mountains (ne croatia).– mineral. petrol., 87/1, 143–162. doi: 10.1007/s00710-006-0120-1 balen, d., horváth, p., finger, f. & starijaš, b. (2013): phase equilibrium, geothermobarometric and xenotime age dating constraints on the alpine metamorphism recorded in chloritoid schists from the southern part of the tisia mega-unit (slavonian mts., ne croatia).– int. j. earth sci. (geol. rundsch.), 102, 1091–1109. doi: 10.1007/s00531-012-0850-8 balen, d., massonne, h.-j. & petrinec, z. (2015): collision-related early paleozoic evolution of a crustal fragment from the northern gondwana margin (slavonian mountains, tisia mega-unit, croatia): reconstruction of the p–t path, timing and paleotectonic implications.– lithos, 232, 211–228. doi: 10.1016/j.lithos. 2015.07.003 balen, d., massonne, h.-j. & lihter, i. (2018): alpine metamorphism of lowgrade schists from the slavonian mountains (croatia): new p-t and geochronological constraints.– int. geol. rev., 60/3, 288–304. doi: 10.1080/00206814. 2017.1328710 balen, d., schneider, p., massonne, h.-j., opitz, j., luptakova, j., putiš, m. & petrinec, z. (2020): the late cretaceous a-type alkali-feldspar granite from mt. požeška gora (n croatia): potential marker of fast magma ascent in the europe–adria suture zone.– geol. charpath., 71/4, 361–381. doi: 10.31577/geolcarp.71.4.5 batchelor, r. a. & bowden, p. (1985): petrogenetic interpretation of granitoid rock series using multicationic parameters.– chem. geol., 48, 43–55. doi: 10.1016/0009-2541(85)90034-8 bau, m. (1996): controls on the fractionation of isovalent trace elements in magmatic and aqueous systems: evidence from y/ho, zr/hf, and lanthanide tetrad effect.– contrib. mineral. petrol., 123, 323–333. doi:10.1007/s004100050159 belak, m., miknić, m., kruk, b., kastmuller, ž. & kruk, lj. (2000): bazalt-glinoviti peperiti: litofacijesni i kronostratigrafski prinos poznavanju vulkanita budima kod voćina [basalt-clayey limstone peperites: lithofacies and chronostratigraphic contribution to the knowledge of the volcanites of the mt. budim near voćin – in croatian, with an english abstract].− zbornik radova, 2. hrvatski geološki kongres, institut za geološka istraživanja, 109‒113. belousova, e.a., walters, s., griffin, w.l., o’reilly, s.y. & fisher, n.i. (2002a): igneous zircon: trace element composition as an indicator of source rock type.– contrib. mineral. petrol., 143, 602–622. doi: 10.1007/s00410-002-0364-7 belousova, e.a., griffin, w.l., o’reilly, s.y. & fisher, n.i. (2002b): apatite as an indicator mineral for mineral exploration: trace-element compositions and their relationship to host rock type.– j. geochem. explor., 76, 45–69. doi: 10.1016/ s0375-6742(02)00204-2 berza, t., constantinescu, e. & vlad, ş.n. (1998): upper cretaceous magmatic series and associated mineralization in the carpathian–balkan orogen.– resour. geol., 48, 291–306. doi: 10.2478/s13386-011-0023-8 biševac, v., balogh, k., balen, d. & tibljaš, d. (2010): alpine (cretaceous) very lowto low-grade metamorphism recorded on the illite-muscovite-rich fraction of metasediments from south tisia (eastern mt papuk, croatia).– geol. carpath., 61, 469–481. boynton, w.v. (1984): geochemistry of the rare earth elements: meteorite studies.– in: henderson, p. (ed.): rare earth element geochemistry. elsevier, 63–114. breiter, k. & škoda, r. (2017): zircon and whole-rock zr/hf ratios as markers of the evolution of granitic magmas: examples from the teplice caldera (czech republic/germany).− mineral. petrol., 111, 435−457. doi: 10.1007/s00710-0170509-z g eo lo gi a c ro at ic a geologia croatica 75/2266 burov, e., guillou-frottier, l., d’acremont, e., le pourhiet, l. & cloetingh, s. (2007): plume head–lithosphere interactions near intra-continental plate boundaries.– tectonophys., 434, 15–38. doi:10.1016/j.tecto.2007.01.002 croatian geological survey (2009): geological map of the republic of croatia, 1:300.000 (geološka karta republike hrvatske).– croatian geological survey, department of geology, zagreb (in croatian). cvetković, v., šarić, k., grubić, a., cvijić, r. & milošević, a. (2014): the upper cretaceous ophiolite of north kozara – remnants of an anomalous mid-ocean ridge segment of the neotethys?– geol. carpath., 65, 117–130. doi: 10.2478/geoca-2014-0008 de la roche, h., leterrier, j., grandclaude, p. & marchal, m. (1980): a classification of volcanic and plutonic rocks using r1r2-diagram and major element analyses – its relationships with current nomenclature.– chem. geol., 29, 183–210. doi: 10.1016/0009-2541(80)90020-0 dickinson, w. & gehrels, g. (2003): u–pb ages of detrital zircons from permian and jurassic eolian sandstones of the colorado plateau, usa: paleogeographic implications.− sediment. geol., 163, 29–66. doi: 10.1016/s0037-0738(03)00158-1 eby, g.n. (1990): the a-type granitoids: a review of their occurrence and chemical characteristics and speculations on their petrogenesis.– lithos, 26, 115–134. doi:10.1016/0024-4937(90)90043-z eby, g.n. (1992): chemical subdivision of the a-type granitoids: petrogenetic and tectonic implications.– geology, 20, 641–644. erdmann, s., wodicka, n., jackson, s.e. & corrigan, d. (2013): zircon textures and composition refractory recorders of magmatic volatile evolution?− contrib. mineral. petr., 165, 45–71. doi: 10.1007/s00410-012-0791-z frezzotti, m.l., tecce, f. & casgali, a. (2012): raman spectroscopy for fluid inclusions analysis.– j. geochem. explor., 112, 1–12. doi: 10.1016/j.gexplo.2011. 09.009 frost, c.d. & frost, b.r. (2011): on ferroan (a-type) granitoids: their compositional variability and modes of origin.– j. petrol., 32, 39–53. doi: org/10.1093/petrology/egq070 frost, b.r., branes, c.g., collins, w.j., arculus, r.j., ellis, d.j. & frost, c.d. (2001): a geochemical classification for granitic rocks.– j. petrol., 42, 2033– 2048. doi: 10.1093/petrology/42.11.2033 fu, b., page, f.z., cavosie, j.c., fournelle, j., kita, n.t., lackey, j.s., wilde, s.a. & valley, j.w. (2008): ti-in-zircon thermometry: applications and limitations.− contrib. mineral. petr., 156, 197–215. doi: 10.1007/s00410-008-02815 gervasoni, f., klemme, s., rocha-júnior, e.r.v. & berndt, j. (2016): zircon saturation in silicate melts: a new and improved model for aluminous and alkaline melts.– contrib. mineral. petr., 171, 21. doi: 10.1007/s00410-016-1227-y harris, n.b.w., pearce, j.a. & tindle, a.g. (1986): geochemical characteristics of collisionzone magmatism.– in: coward, m.p. & ries, a.c. (eds): collision tectonics.– geol. soc. london spec. publ., 19, 67–81. harrison, t.m. & watson, e.b. (1984): the behavior of apatite during crustal anatexis: equilibrium and kinetic considerations.– geochim. cosmochim. acta, 48, 1467–1477. doi: 10.1016/0016-7037(84)90403-4 hoskin, p.w.o. & schaltegger, u. (2003): the composition of zircon and igneous and metamorphic petrogenesis.– rev. mineral. geochem., 53, 27–62. doi: 10.2113/0530027 hoskin, p.w.o., kinny, p.d., wyborn, d. & chappell, b.w. (2000): identifying accessory mineral saturation during differentiation in granitoid magmas: an integrated approach,– j. petrol., 41/9, 1365–1396. doi: 10.1093/petrology/41.9.1365 horváth, p., balen, b., finger, f., tomljenović, b. & krenn, e. (2010): contrasting p-t-t paths from the basement of the tisia unit (slavonian mts., ne croatia): application of quantitative phase diagrams and monazite age dating.– lithos, 117, 269–282. doi: 10.1016/j.lithos.2010.03.004 horvat, m., klötzli, u., jamičić, d., buda, g., klötzli. e. & hauzenberger, ch. (2018): geochronology of granitoids from psunj and papuk mts., croatia.– geochronometria, 45/1, 198–210. doi: 10.1515/geochr-2015-0099 hurai v., huraiová, m., slobodník, m. & thomas r. (2015): geofluids – developments in microthermometry, spectroscopy, thermodynamics, and stable isotopes.− elsevier, amsterdam, 489 p. ilinca, g., berza, t., iancu, v. & seghedi, a (2011): field trip guidebook, the late cretaceous magmatic and metallogenetic belt and the alpine structures of the western south carpathians. 3rd international symposium on the geology of the black sea region, bucharest, 1–10 october 2011, 117 p. jamičić, d. (1983): strukturni sklop metamorfnih stijena krndije i južnih padina papuka [structural fabric of the metamorphosed rocks of mt. krndija and the eastern part of mt. papuk – in croatian, with an english summary].− geol. vjesnik, 36, 51‒72. jamičić, d. (1988): strukturni sklop slavonskih planina [structural fabric of the slavonian mts. (northern papuk, psunj, krndija) – in croatian, with an english summary].− phd thesis, faculty of science, university of zagreb, 152 p. jamičić, d. (1989): osnovna geološka karta sfrj 1:100000, list daruvar l 33-95 [basic geological map of sfry 1:100000, daruvar sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. jamičić, d. & brkić, m. (1986): osnovna geološka karta sfrj 1:100000, list orahovica l 33-96 [basic geological map of sfry 1:100000, orahovica sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. jamičić, d., brkić, m., crnko, j. & vragović, m. (1987): osnovna geološka karta sfrj 1:100000. tumač za list orahovica l 33-96 [basic geological map of sfry 1:100000, geology of the orahovica sheet – in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd, 72 p. jamičić, d., vragović, m. & matičec, d. (1989): osnovna geološka karta sfrj 1:100000. tumač za list daruvar l 33-95 [basic geological map of sfry 1:100000, geology of the daruvar sheet – in croatian].− geološki zavod, zagreb, savezni geološki zavod, beograd, 55 p. janoušek, v., farrow, c.m. & erban, v. (2006): interpretation of whole-rock geochemical data in igneous geochemistry: introducing geochemical data toolkit (gcdkit).– j. petrol., 47, 1255–1259. doi: 10.1093/petrology/egl013 kempton, p.d., harmon, r.s., hawkesworth, c.j. & moorbath, s. (1990): petrology and geochemistry of lower crustal granulites from the geronimo volcanic field, southeastern arizona.– geochim. cosmochim. acta, 54, 3401–3426. doi:10.1016/0016-7037(90)90294-u king, p.l., white, a.j.r., chappell, b.w. & allen, c.m. (1997): characterization and origin of aluminous a-type granites from the lachlan fold belt, southeastern australia.– j. petrol., 38, 371–391. doi:10.1093/petroj/38.3.371 kirkland, c.l., smithies, r.h., taylor, r.j.m., evans, n. & mcdonald, b. (2015): zircon th/u ratios in magmatic environs.– lithos, 212–215, 397–414. doi: 10.1016/j.lithos.2014.11.021 koch, f. (1919): grundlinien der geologie von west-slavonien.– glasnik hrv. prir. dr., 31/2, 217–236. lugović, b. (1983): efuzivne stijene sjeverozapadnog dijela papuka. [extrusive rocks from the nw part of mt. papuk (croatia, yugoslavia) – in croatian, with an english summary].– geol. vjesnik, 36, 131–156. lužar-oberiter, b., mikes, t., dunkl, i., babić, lj. & von eynatten, h. (2012): provenance of cretaceous synorogenic sediments from the nw dinarides (croatia).– swiss j. geosci., 105, 377–399. doi: 10.1007/s00015-012-0107-3 mclennan, s.m. (1994): rare earth element geochemistry and the “tetrad” effect.– geochim. cosmochim. acta, 58, 2025–2033. doi:10.1016/0016-7037(94)90282-8 paces, j.b. & miller, j.d. (1993): precise u–pb ages of duluth complex and related mafic intrusions, northeastern minnesota: geochro nological insights into physical, petrogenetic, paleomagnetic and tectonomagmatic processes associated with the 1.1 ga midcontinent rift system.– j. geophys. res., 98, 13997–14013. doi: 10.1029/93jb01159 pamić, j. (1987): mladoalpinski alkalijsko-feldspatski graniti (aljaskiti) požeške gore u slavoniji [young-alpine alkali feldspar granites (alaskites) from mt. požeška gora in slavonia, northern yugoslavia – in croatian, with english summary].− geologija, 30, 183–205. pamić, j. (1991): gornjokredne bazaltoidne i piroklastične stijene iz voćinske vulkanske mase na papuku (slavonija, sj. hrvatska) [upper cretaceous basaltoid and pyroclastic rocks from the voćin volcanic mass on the papuk mt. (slavonija, northern croatia) – in croatian, with an english summary].– geol. vjesnik, 44, 161–172. pamić, j. (1993): eoalpine to neoalpine magmatic and metamorphic processes in the northwestern vardar zone, the easternmost periadriatic zone and the southwestern pannonian basin.– tectonophysics, 109, 273–307. doi: 10.1016/00401951(93)90135-7 pamić, j. (1997): vulkanske stijene savsko-dravskog međuriječja i baranje (hrvatska) [volcanic rocks of the sava-drava interfluve and baranja (croatia) – in croatian, with english summary].– nafta, zagreb, 192 p. pamić, j. (2002): the sava-vardar zone of the dinarides and hellenides versus the vardar ocean.– eclogae geol. helv., 95, 99–113. doi: 10.5169/seals-168948 pamić, j. & injuk, j. (1988): alpinske granitoidne stijene prosare u sjevernoj bosni.– zbor. ref. nauč. skupa “minerali, stijene, izumrli i živi svijet bih”, 93–103, sarajevo. pamić, j. & lanphere, m. (1991a): hercynian granites and metamorphic rocks from the papuk, psunj, krndija and the surrounding basement of the pannonian basin (northern croatia, yugoslavia).– geologija, 34, 81–253. pamić, j. & lanphere, m. (1991b): a-type granites from the collisional area of the northernmost dinarides and pannonian basin. neues jahrb. mineral. abh., 161, 215–236. pamić, j., lanphere, m. & mckee, e. (1988): radiometric ages of metamorphic and associated igneous rocks of the slavonian mountains in the southern part of the pannonian basin.– acta geol., 18, 13–39. pamić, j., injuk, j. & jakšić, m. (1988/1989): prilog geokemijskom poznavanju gornjokredne bimodalne vulkanske asocijacije požeške gore u slavoniji (sjeverna hrvatska, jugoslavija) [some geochemical features of the upper cretaceous bimodal volcanic association from the požeška gore mt. in slavonija (northern croatia, yugoslavia) – in croatian, with an english summary].− geologija, 31–32, 415–435. g eologia c roatica schneider et al.: dating and geochemistry of zircon and apatite from rhyolite at the unesco geosite rupnica (mt. papuk, northern croatia) ... 267 patiño douce, a.e. (1997): generation of metaluminous a-type granites by lowpressure melting of calc-alkaline granitoids.– geology, 25, 743–746. doi:10.1130/0091-7613 piccoli, p.m, & candela, p.a. (1994): apatite in felsic rocks: a model for the estimation of initial halogen concentrations in the bishop tuff (long valley) and tuolumne intrusive suite (sierra nevada batholith) magmas.– am. j. sci., 294, 92–135. doi: 10.2475/ajs.294.1.92 piccoli, p.m. & candela, p.a. (2002): apatite in igneous systems.– rev. mineral. geochem., 48, 255–292. doi: 10.2138/rmg.2002.48.6 pearce, j.a. (1996): sources and settings of granitic rocks.– episodes, 19, 120–125. doi: 10.18814/epiiugs/1996/v19i4/005 pearce, j.a., harris, n.b.w. & tindle, a.g. (1984): trace element discrimination diagrams for the tectonic interpretation of ranitic rocks.– j. petrol., 25, 956–981. poljak, j. (1939): izvještaj o geološkom snimanju lista slatina-voćin (1:25.000).– godišnjak geol. inst. kr. jug. 1938, 1, 89–92, beograd (in croatian). pupin, j.p. (1980): zircon and granite petrology.– contrib. mineral. petr., 73, 207–220. doi: 10.1007/bf00381441 pupin, j.p. (2000): granite genesis related to geodynamics from hf-y in zircon.– trans. r. soc. edinburgh: earth sci., 91, 245–256. doi : 10.1017/s0263593300007410 pupin, j.p. & turco, g. (1972): une typologie originale du zircon accessoire.– bull. soc. fr. minéral. cristallogr., 95, 348–359. schiller, d. & finger, f. (2019): application of ti-in-zircon thermometry to granite studies: problems and possible solutions.– contrib. mineral. petr., 174, 51. doi: 10.1007/s00410-019-1585-3 schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alps– carpathians–dinarides connection: a compilation of tectonic units.– swiss j. geosci., 101, 139–183. doi: 10.1007/s00015-008-1247-3 schmid, s.m., fügenschuh, b., kounov, a., maţenco, l., nievergelt, p., oberhänsli, r., pleuger, j., schefer, s., schuster, r., tomljenović, b., ustaszewski, k. & van hinsbergen, d.j.j. (2020). tectonic units of the alpine collision zone between eastern alps and western turkey.– gondwana res., 78, 308–374. doi: 10.1016/j.gr.2019.07.005 shaulis, b., lapen, t.j. & toms, a. (2010): signal linearity of an extended range pulse counting detector: applications to accurate and precise u-pb dating of zircon by laser ablation quadrupole icpms.− geochem. geophys. geosyst., 11, q0aa11. doi: 10.1029/2010gc003198 skjerlie, k.p. & johanson, a.d. (1993): fluid-absent melting behavior of an f-rich tonalitic gneiss at mid-crustal pressures: implications for the generation of anorogenic granites.– j. petrol., 34, 785–815. doi:10.1093/petrology/34.4.785 sláma, j., kosler, j., condon, d.j., crowley, j.l., gerdes, a., hanchar, j.m., horstwood, m.s.a., morris, g.a., nasdala, l., norberg, n., schaltegger, u., schoene, n., tubrett, m.n. & whitehouse, m.j. (2008): plesovice zircon – a new natural reference material for u–pb and hf isotopic microanalysis.− chem. geol., 249, 1–35. doi: 10.1016/j.chemgeo.2007.11.005 słodczyk, e., pietranik, a., breitkreuz, c., fanning, c., anczkiewicz, r., ehling, b.-c. (2016): rhyolite magma evolution recorded in isotope and trace element composition of zircon from halle volcanic complex.– lithos, 248‒251, 402‒417. doi: 10.1016/j.lithos.2016.01.029 slovenec, d., belak, m., mišur, i., šegvić, b. & schuster, r. (2020): the early paleozoic cumulate gabbroic rocks from the southwest part of the tisza megaunit (mt. papuk, ne croatia): evidence of a gondwana suture zone.– int. j. earth. sci. (geol. rundsch.), 109, 2209–2233. doi: 10.1007/s00531-020-01896-8 starijaš, b., gerdes, a., balen, d., tibljaš, d. & finger, f. (2010): the moslavačka gora crystalline massif in croatia: a cretaceous heat dome within remnant ordovician granitoid crust.– swiss. j. geosci., 103, 61–82. doi: 10.1007/ s00015-010-0007-3 streckeisen, a. (1974): classification and nomenclature of plutonic rocks.– geol. rundsch., 63, 773–786. streckeisen, a. (1978): iugs subcommission on the systematics of igneous rocks: classification and nomenclature of volcanic rocks, lamprophyres, carbonatites and melilitic rocks; recommendation and suggestions.– neues jb. mineral abh., 134, 1–14. stur, d. (1861/62): die neogen tertiären ablagerungen von west slavonien.– jahrb. reichanst, 12, 285–299. sun, s.s. & mcdonough, w.f. (1989): chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes.– in: saunders, a.d. & norry, m.j. (eds.): magmatism in ocean basins.– geol. soc. spec. publ., 42, 313–345. doi: 10.1144/gsl.sp.1989.042.01.19 tajder, m. (1956): albitski efuzivi okolice voćina i njihova geneza [the albite volcanic rocks of the voćin area and their origin – in croatian, with an english summary].– acta geol. 1 (prir. istraž. jazu), 27, 35–48. tajder, m. (1960): anortoklasni egirinski riolit iz potoka rupnice kod voćina [anorthoclase-aegirine-rhyolite from rupnica brook near voćin – in croatian, with an english summary].– acta geol. 2 (prir. istraž. jazu), 29, 95–101. ustaszewski, k., schmid, s.m., lugović, b., schuster, r., schaltegger, u., bernoulli, d., hottinger, l., kounov, a., fügenschuh, b. & schefer, s. (2009): late cretaceous intra-oceanic magmatism in the internal dinarides (northern bosnia and herzegovina): implications for the collision of the adriatic and european plates.– lithos, 108, 106–125. doi: 10.1016/j.lithos.2008.09.010 ustaszewski, k., kounov, a., schmid, s.m., schaltegger, u., krenn, e., frank, w. & fügenschuh, b. (2010): evolution of the adria–europe plate boundary in the northern dinarides: from continent–continent collision to back-arc extension.– tectonics, 29, tc6017. doi: 10.1029/2010tc002668 wang, x, griffin, w.l. & chen, j. (2010): hf contents and zr/hf ratios in granitic zircons.− geochem. j., 44, 65−72. doi: 10.2343/geochemj.1.0043 watson, e.b. & harisson, t.m. (1983): zircon saturation revisited: temperature and composition effects in a variety of crustal magma types.– earth planet. sci. lett., 64, 295–304. doi: 10.1016/0012-821x(83)90211-x watson, e.b., wark, d.a. & thomas, j.b. (2006): crystallization thermometers for zircon and rutile.– contrib. mineral. petr., 151, 413–433. doi: 10.1007/s00410006-0068-5 whalen, j.b., currie, k.l. & chappell, b.w. (1987): a-type granites: geochemical characteristics, discrimination and petrogenesis.– contrib. mineral. petr., 95, 407–419. doi: 10.1007/bf00402202 zimmerman, a., stein, h.j., hannah, j.l., koželj, d., bogdanov, k. & berza, t. (2008): tectonic configuration of the apuseni–banat–timok–srednogorie belt, balkans-south carpathians, constrained by high precision re–os molybdenite ages.– miner. deposita, 43/1, 1–21. doi: 10.1007/s00126-007-0149-z 2023 | 76/3 | 105–112 | 10 figs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the liburnian coast is located on the western coast of rijeka bay. it is part of the kvarner channel zone of the northeastern adriatic (figure 1). the relief of the southern part of this coast looks like an escarpment. this escarpment, with a length of 6.5 km, is chara­ cterized by very steep to vertical slopes, which reach a height of 100 m above mean sea level. the submarine slopes are also very steep, so that the –50 isobaths run close to the coastline according to the navionics chart (figure 1a). high seismicity indicates active tectonic activity in recent times in the kvarner area (markušić et al., 2019; korbar et al., 2020). the northward displacement of the istrian peninsula has been determined based on gps measurements (weber et al., 2010). an istrian normal fault or the kvarner fault zone strik­ ing nne­ssw along the liburnian coast is very tectonically ac­ tive (del ben et al., 1991; korbar, 2009; placer et al., 2010). as a result of tectonic movements, very steep or vertical scarps are formed in the carbonate rocks or at the carbonate fly­ sch contact according to the authors. rock falls and rock slides have been found and described in the kvarner area in the rječina river valley along the carbonate – flysch contact (benac et al., 2009; benac et al., 2011). several active or dormant landslides of smaller dimensions formed in colluvium deposits on flysch have been found on the kvarner coasts, and they are a cause of marine erosion (juračić et al., 2009; ružić et al., 2014). landslides on the italian adriatic coast have a similar cause (iadanza et al., 2009). however, the cor­ relation between the numerous high escarpments and the possible large gravitational collapse structure on a rocky coast (kvarner, ne adriatic sea) čedomir benac1, sanja dugonjić jovančević1, dražen navratil2, andrea tadić1 and lovro maglić3 1 university of rijeka, faculty of civil engineering, r. matejčić 3, 51000 rijeka, croatia; (sanja.dugonjic@gradri.uniri.hr) 2 croatian geological survey, saschova 2, 10000 zagreb, croatia 3 university of rijeka, faculty of maritime studies, studentska 2, 51000 rijeka, croatia doi: 10.4154/gc.2023.10 abstract the studied rock collapse structure is located on the liburnian coast (rijeka bay, channel zone of the ne adriatic). the relief of the southern part of this coast, with a length of 6.5 km, is a large escarpment with very steep to vertical slopes reaching heights of 100 m above sea level, as a result of tectonic movements along the kvarner fault zone. these events probably led to a sudden relaxation of the highly fractured rock mass. the progressive expansion occurred at locations where previously favourably oriented faults and fissures had formed a polygonal rock collapse resembling a rock-slide which is the focus of this study. another aim of this study is to reconstruct and explain the complex morphological evolution of the studied landslide, from the pre-failure deformations, through the failure itself, to post-failure displacements, as well as possible future instabilities. recent techniques to survey the instability, location and to analyse the evolution of the rupture surface and its dimensions were combined (unmanned aerial vehicle, side scan sonar and remotely operated vehicles). the estimated total volume of displaced rock mass is 950,000 m3. the lower part of the instability phenomenon was submerged during the holocene sea level rise. since then, a large part of the displaced rock mass has been in a stable position, with sporadic rock falls. however, given unfavourable orientation and discontinuity characteristics, as well as unfavourable environmental influences, possible instabilities might also be expected in the future. instability phenomena along the kvarner coast has not yet been scientifically explained. the large gravitational rock collapse on the liburnian coast studied here (figure 1b) is located on a terrain with very steep coastal morphology, accessible only from the sea. the vertical article history: manuscript received may 11, 2023 revised manuscript accepted september 14, 2023 available online october 16, 2023 keywords: coastal instability, tectonic movements, rock slide, rock fall, structural analysis, sfm-mvs photogrammetry, submarine survey figure 1. location maps: a) the liburnian coast b) study area. legend: 1. south učka mt. reverse faults 2. suposed strike of kvarner fault zone, 3. studied collapse structure. g eo lo gi a c ro at ic a geologia croatica 76/3106 scarps bordering the sliding body are up to 100 m high, and the landslide toe is at a depth of about 40 m below mean sea level. modern techniques offer the possibility to explore the phenomena under these conditions (james & robson, 2012; fonstad et al., 2013). here, the aforementioned scarps were surveyed us­ ing an unmanned aerial vehicle (uav)1. recent surveying techniques are also being used in investi­ gating submarine zones (shang et al., 2019). in this research, the submarine zone was surveyed using a side­scan echo sounder and diving equipment, and remotely operated vehicles (rovs). based on the results obtained from the proposed methodology and analyses presented in the paper, the origin and geomorpho­ logical evolution of the investigated rock collapse is presented and discussed. 2. geological structure and geomorphological evolution the wider study area is part of the lower (southern) overthrust of the ridge of the učka mt. (figure 1a). overturned folds and re­ verse faults of the paraclasis dipping northeast, are common within the lower overthrust. upper cretaceous rudist limestones predominate in the southern liburnian coastal zone. the lime­ stone rocks exhibit distinct bedding. the bedding planes are mostly inclined to the east and southeast. the flysch rock mass is squeezed between the carbonate rocks and is mostly covered by younger colluvial deposits. tectonic breccia has been found near reverse faults (šikić et al., 1969; hgi, 2009). the movement of the adria plate towards the northeast and north is the main cause of the geodynamic evolution of the istrian peninsula and the kvarner area (marinčić & matičec, 1991). this evolution took place in two phases: the first phase from the eocene to the pliocene and the second phase from the upper pliocene to the present. during the first phase, the princi­ pal regional stress was ne–sw. the structures formed during this phase have a dinaric strike (nw–se). it is considered that the main uplift with exhumation in the kvarner area occurred during the first phase of the dinaridic compression. the absence of miocene and pliocene marine sediments indicates that the east­ ern slopes of učka mt. may have remained emerged since the late neogene (korbar, 2009). this emersion caused the denuda­ tion of siliciclastic sediments and the beginning of intense karsti­ fication. the istrian peninsula was separated from the highly de­ formed adriatic segment with the kvarner fault zone and rotated towards the northeast where it is underthrust beneath the exter­ nal dinarides (placer et al., 2010). during the second phase of the orogeny, the principal re­ gional stress changed to a n­s direction. this change caused the reactivation of pre-existing structures. during this tectonic phase the učka mt. ridge acquired its present-day nne-ssw (meridional) strike (marinčić & matičec, 1991). transpression and radial extension during the last phase of regional stress caused deformation of younger diagonal and transverse dextral strikeslip faults and opposite vertical tectonic movements on the east­ ern slopes of učka mt. the key prerequisite for the appearance of today’s very steep southern liburnian coast is the structural arrangement of the discontinuities in the carbonates along the kvarner fault zone (mihljević, 1996). the relatively rectilin­ ear extension of the liburnian coast is believed to be a conse­ 1 shape metrix uav 3d imaging for measuring and assessing rock and terrain surfaces drone imagery. user manual for version 4.3. 3gsm gmbh, graz, 2021. https://3gsm.at/produkte/shape-metrix-uav/ quence of the kvarner fault zone or the istrian fault (del ben et al., 1991). the interruption of the geological structures of the kvarner islands towards the northwest is visible on geological maps (korbar, 2009). a relatively narrow and elongated karst plateau is located between the ridge of the southern učka mt. and rijeka bay. this plateau is slightly inclined towards rijeka bay and is strongly limited by the aforementioned escarpment along the liburnian coast. due to the carbonate rock mass disintegration and erosion, slope deposits have accumulated at the foot of the fault (mihljević, 1996). this rock mass is karstified to about 70 m below recent sea level. intense morphogenetic processes caused by neotectonic movements and rapid changes in sea level, as well as climatic changes, have shaped the present form of the kvarner area, and also the relief of the studied area (benac & juračić, 1998) (figure 2). 3. methods a wide coastal area was surveyed using a uav in october 2021. the survey covered a coastal strip with a length of about 6.5 km and an average width of about 100 m. based on uav acquired images, a photorealistic 3d model was created. after a detailed analysis of this photorealistic model, the instability phenomenon and a study zone were selected for a detailed survey. the second uav survey was conducted in may 2022. the 3d point cloud was generated using the structure from motion (sfm) with multi­view stereo (mvs) photogrammetry. the im­ age sets were processed using sfm­mvs software agisoft metashape professional, v1.7.1. images were captured in jpg for­ mat using the uav dji phantom 4 professional, fc6310 camera with 20-megapixel, 100 cmos sensor, 8.8 mm focal length. due to its complex morphology, images were taken from different dis­ tances from the coastline, and from different camera angles. the overlap between images was constant, with all areas covered by more than 9 overlapping images. a total of 604 images were ac­ quired for the 0.0437 km² of complex coastline. the flight altitude was 26 m, resulting in a ground resolution of 1.05 cm/pixel. shapemetrix uav is used for metric acquisition of rock and terrain surfaces and noncontact measurement of geological/geo­ technical parameters through 3d metric models. results obtained include comprehensive documentation of the 3d model, geometry of imaged rock faces, measurement of geometric features such as points, distances, areas, spatial orientations, and integrated features for determining space, or hemispherical plots. site mapping, i.e., seafloor morphology analysis, which in­ cluded bathymetry survey, 3d mapping, and seafloor profile scan­ figure 2. simplified geological cross-section of the wider area. 1 – carbonate rock mass, 2 – marine sediments, 3 – neotectonic fault https://3gsm.at/produkte/shape-metrix-uav/ g eologia c roatica benac et al.: large gravitational collapse structure on a rocky coast (kvarner, ne adriatic sea) 107 ning, was conducted with humminbird solix 12 side-scan sonar chirp msi + gps g2. the measurements were post-processed using humminbird’s autochart pro software. this sonar com­ bines tournament­ready mega side imaging+, mega down imaging+, and dual spectrum chirp sonar technologies. this high­resolution 1,100 khz sonar is suitable for selected sites, i.e., for measurements at relatively shallow depths down to 60 metres. other operating frequencies of the sonar are 200, 455, and 800 khz. the size of the surveyed area (at the sea surface) was ap­ proximately 190 m × 80 m or 15,200 m2. the sonar was mounted on a rib (rigid inflatable boat) below the hull and engine to avoid interference. during the survey, the sea was calm and the cruising speed was 2 knots. to obtain the most accurate data, the area was surveyed in a mesh pattern, i.e., navigating parallel and perpendicular to the shoreline at 10 m intervals. the depths ob­ tained were corrected for tidal height during recording and there­ fore represent depths based on a hydrographic datum (chart da­ tum). interesting parts of the submarine slopes were surveyed us­ ing diving equipment and an rov. video and photo documenta­ tion of the sea bottom relief was obtained using the blueye pio­ neer inspection class rov manufactured by blueye robotics and installed on a boat anchored in the middle of the surveyed area near the coast. the rov has a built-in fhd camera with a lightsensitive wide-angle lens (1080p / 30 fps) and a powerful 3300-lu­ men led, which allows recording at night, at great depths, and/ or in poor visibility conditions. four powerful 350-watt thrusters enabled fast and precise movements in all directions. the rov was immersed in the sea and imaging began im­ mediately from the sea surface. this vehicle was operated ac­ cording to a predetermined movement and recording plan. the plan called for recording two straight transects perpendicular to the shoreline. the first transect ran from the shallowest part of the sea bottom near shore along the entire slope to its end at depth, i.e., to the area where the shallow sea-bottom with fine sediments begins, at approximately -50 m. the second transect was in the opposite direction, from the bottom of the slope to the shallowest area near the shore. both transects were located in the central part of the study area and were approximately 30 m apart. it should be emphasised that the rov used is designed to al­ ways be in an upright position, which means that all underwater objects and slopes seen in the photos and videos are as in reality. based on the video documentation recorded by the rov, a geo­ logical map of the submarine part of the investigated site was cre­ ated. however, data obtained from sfm­mvs photogrammetry were very useful in interpreting the surface part of the geological map. all modern imaging techniques of both the surface and un­ derwater parts of the study area were used in the detailed inter­ pretation and morphological evolution analysis of the resulting rock mass failure. using the overall 3d model and known facts from the previous research, the morphological analysis of the wider area was presented. key points needed to complete the whole theory of the origin of the rock mass failure were analyzed in detail, presented in the results, and later discussed in the mor­ phological evolution of investigated rock slide as well as in the tectonic interpretation of the collapse structure. 4. results the extension of the linear coastal escarpment, located at the edge of the karst plateau of the southern liburnian coast, is inter­ rupted by the semi­circular rock collapse. the studied collapse structure is separated from the edge of the karst plateau by a sys­ tem of fractures (faults and fissures) which form a polygonal out­ line of the main escarpment. the analysis revealed several sub­vertical discontinuities (89/88°; 16/89°; 22/88°; 140/89°; 233/80°) that define the position of the main scarp and lateral fracture. this is visible in a photo­ realistic model (figure 3a) and is shown on the diagram in the stereographic projection (figure 3b). it was also established that the strike direction and dip angle of the bedding plane (104/28°) are the same on both sides of the collapse structure (figure 3b). figure 3. a) photorealistic 3d model of the study area, acquired by sfm-mvs photogrammetry, b) analysis of the orientation of discontinuity planes (faults and fissures). g eo lo gi a c ro at ic a geologia croatica 76/3108 the vertical scarps adjacent to the rock collapse are several tens of metres high. based on this survey and analysis, it was concluded that the polygonal shape of the sliding surface is pre­ disposed by the location of the favourably oriented faults and fis­ sures. rock mass surrounding the rock collapse consists of the up­ per cretaceous rudist limestones. the limestones show a distinct layering, with bedding planes uniformly inclined to the southeast with a dip angle of 28°. the layers are 10 to 100 cm thick. in ad­ dition to bedding planes, vertical or oblique fissures are also visible. this kind of structural fabric can favour the collapse of both sides of the described collapse structure (figures 5a and 5b). the rock mass in the collapse structure consists of cataclas­ tic breccias. the size of the angular fragments ranges from a few centimetres to blocks over one metre in diameter. the matrix consists of calcitic reddish clay (figure 6). the landslide toe is located at a depth of about 40 m below mean sea level. the total volume of the displaced rock mass was estimated from the 3d model as about 950,000 m3. based on the underwater survey, the roughness of the submarine relief is ex­ pressed, and the slope has a very uneven inclination (figure 4). the bare rocky part is visible at a depth between 15 and 20 m (figures 4, 7 and 8a). boulders with a diameter of up to one metre reach a depth of 40 m (figures 4 and 8b). the deeper part of the bottom is slightly inclined and covered with sandy sediments. the total height (from the crown to the landslide toe) is 130 m. the geometry of the studied instability was described accord­ ing to the nomenclature for landslides proposed by wp/wli (iaeg, 1990) (figures 4 and 7): – the total length: l = 210 m; – the length of the displaced mass: ld = 200 m; – the width of the displaced mass: wd = 135 m; – the width of the fracture surface: wr = 135 m. the investigated collapse structure cannot be strictly classi­ fied into one type of landslide. in the initial phase of development, it was a rock collapse, because sliding of a rock mass occurred on a rupture surface consisting of several planes. rock collapse occurred on an irregular rupture surface consisting of a number of randomly oriented joints, separated by segments of intact rock. in the second phase, lasting until the present day, rock falls are still occurring, according to the varnes classification (hungr et al., 2013). figure 4. geological map of rock slide 1-upper cretaceous limestones, 2-cataclastic breccias, 3-colluvial boulders and blocks, 4-seabed sand with coarse fragments, 5-strike and inclination of bedding plane, 6-main scarp, 7-lateral discontinuities, 8-landslide toe, 9-geological boundary, 10-cross section (see figure 7), 11-position of photos. figure 5. structural interpretation of a possible slide in layered upper cretaceous limestones: a) south side, b) north side. both red arrows are oriented to the east. figure 6. cataclastic breccia in collapse structure (photo: č. benac). figure 7. geological cross-section (see figure 4): 1-upper cretaceous limestones, 2-cataclastic breccia, 3-boulders and fragments, 4-seabed sand with coarse fragments, 5-boundary of collapse structure (established or assumed), 6-geological boundary (established or assumed). g eologia c roatica benac et al.: large gravitational collapse structure on a rocky coast (kvarner, ne adriatic sea) 109 5. discussion the activity of the fault in the neogene caused vertical tectonic movements, and at the same time, the ridge of the southern učka was uplifted (marinčić & matičec, 1991). during the last phase of the tectonic evolution of the istrian peninsula and the kvarner area, tectonic movements along the kvarner fault zone might have been active (korbar, 2009; placer et al., 2010). these events could have the main impact on the formation of an escarpment in the southern part of the liburnian coast. recent tectonic activity in the wider area (markušić et al., 2019) probably triggered collapse events and caused the displacement of a large block of cataclastic breccia (figures 1a and 2). global positioning system (gps) and the inferred northward and north­ eastward movement of the istrian peninsula confirms this hy­ pothesis (weber et al., 2010). the present form of the described collapse structure has the shape of a rock slump, however, as de­ scribed earlier, it can be classified as a rock collapse with char­ acteristics of a compound rock slide (hungr et al., 2013.). mor­ phological evolution of the instability probably took place in four phases (figure 9). due to the subsidence of the present seabed, the formation of initial scarps occurred in phase a. this event led to a relaxa­ tion of the rock mass. progressive extension occurred at the loca­ tions of previously formed and favourably oriented paraclases of faults and fissures. in phase b, detachment of a block of the cataclastic breccia from the main slope and the beginning of a rock collapse or compound rock slide occurred. phase c led to the dis­ integration of the frontal part of the sliding body of the detaching large rocky blocks and the onset of periodic rock fall. sea flood­ ing of the lower part of the displaced material occurred in phase d, allowing the influence of sea erosion, partial rock fall and de­ bris fall, and sedimentation of fine-grained sediments. an important question is when the described rock collapse might have occurred. it certainly occurred before the late pleis­ tocene and holocene sea level rise. clear evidence of this is pro­ vided by well­developed tidal notches, which are located on the coast within and around the displaced rock mass. tidal notches are widespread along the carbonate coasts in the rijeka bay and on the liburnian coast (benac et al., 2004). the measurement shows that the roofs of the tidal notches (elevation point e*) are figure 8. a) very steep rocky bottom of the submerged part of the rock collapse at a depth of 15 m b) boulders at the landslide toe at a depth of 34 m (photo: l. maglić). figure 9. morphological evolution of the studied instability phenomenon. g eo lo gi a c ro at ic a geologia croatica 76/3110 located at a depth of 56 ± 2 cm (collapse structure) and 57 ± 2 cm (northern part of the coast) (figure 10). similar depths of eleva­ tion points have been found elsewhere on the liburnian coast (benac et al., 2004). therefore, it can be assumed that the up­ per part of the sliding body was in a relatively stable position be­ fore the late pleistocene­holocene sea level rise. in the northern adriatic, near the eustatic peak of holocene sea level rise, a period of equilibrium between regional tectonic subsidence and hydro­isostatic uplift was postulated. these two opposing processes probably caused relative sea level to remain stable for several thousand years (pirazzoli, 2005; benja­ min et al., 2017). however, to explain the elongated shape of the notches in the kvarner area, their excellent preservation (espe­ cially the notch roofs), and their present location, it has already been proposed that there was a long period of rather slow relative sea level rise before rapid tectonic (coseismic) subsidence (benac et al., 2004). this relative sea level standstill or very slow rise allowed the development of intertidal notches in rela­ tive resistant carbonate rocks. at the same time, the development of cliffs and narrow, pocket beaches on less resistant, highly frac­ tured rocks can be observed (benac & juračić, 1998; juračić et al., 2009). wave heights in the channel part of the northern adriatic are lower than in the western open zone, which is due to the relatively short wind fetch. the strongest northeast wind (bura or bora in italian), does not produce the highest waves due to the short wind fetch. alternatively, the stormy southeast wind (jugo or scirocco in italian) with a speed of 20 m/s can generate the highest waves (over 6 m) on the western open coast of the islands of cres and lošinj. the rijeka bay and the vela vrata strait are relatively closed channel parts with limited fetch areas and a tidal range between 30 and 35 cm (penzar et al., 2001). the studied coastal area is exposed to wind-driven waves from the south, southeast, north and northeast directions, and the waves are lower than in the open adriatic. as a result of bioerosion, tidal notches are well developed in cataclastic breccias, as well as in the surrounding limestone (figure 10). this means that the rock mass is suffi­ ciently resistant, so the impact of the waves and mechanical ero­ sion is minimal. since the beginning of instrumental measurements, sea level rise in the northern adriatic has been recorded in the range of 2.0 ± 0.9 – 3.4 ± 1.1 mm/year (tsimplis et al., 2012; surić et al., 2014). according to new analyses, the predicted sea level rise by the end of the 21st century could be 62 ± 14 cm (orlić & pasarić, 2013). new climate models predict extreme wave storms (bonaldo et al., 2017) and increased marine erosion (gallina et al., 2019). if we consider the possible future instabilities on this loca­ tion, with regard to the unfavourable orientation and discontinu­ ity features, but also the described external influences on the rock mass, we should consider possible instabilities of bedding planes on both sides of the studied rock collapse, as the next phase in the morphological evolution. the bedding plane position is 104/28° (figure 5). because of their unfavourable orientation in relation to the coastline and their reduced physical­mechanical properties due to marine erosion, sea level rise, strong winds, and wind­ figure 10. tidal notches: e* elevation point. g eologia c roatica benac et al.: large gravitational collapse structure on a rocky coast (kvarner, ne adriatic sea) 111 driven waves, discontinuities likely serve as initial patterns for the development of instability. discontinuities that are diagonal to bedding planes, and discontinuity planes with dip vectors that form an oblique dihedral angle with the bedding planes dip vec­ tor, both contribute significantly to the development of instabili ty. the aforementioned discontinuities are more persistent than others and run transverse to the bedding plane (figure 5). 6. conclusion along the southern part of the liburnian coast, there is a 6.5 km long escarpment of carbonate rocks with very steep or vertical slopes more than 100 m high. the submarine slopes are also very steep so the isobath of ­50 runs close to the coast. this steep slope was formed during the transpressive deformation along the kvarner fault zone. several large rock slides were recorded along this coast. the instability studied is a large gravitational collapse structure or rock collapse. this is one of the most interesting phe­ nomena on this part of the coast. the earthquakes recorded in the wider kvarner area proba­ bly led to a sudden release of the highly fractured rock mass bounded by the large discontinuities and to the formation of ini­ tial scarps. the progressive expansion occurred at the locations of previously formed and favourably oriented paraclases of faults and fissures. subsequently, the detachment of a block of cataclas­ tic breccia from the main slope and the beginning of a collapse structure or a rock slump occurred. the disintegration of the front part of the rock slump body and the periodic rockfalls continue to the present day. the lower part of the landslide was submerged during the holocene sea level rise. since then, a large part of the displaced rock mass has been in a stable position, resulting in a similar height to the reference points of the tidal notches on and around the landslide body. due to climate change and sea level rise, higher wave action is expected in the future at the study site. this may lead to accel­ erated erosion of cataclastic breccias and displacement of blocks located along bedding planes and fracture systems, as well as in­ stabilities of bedding planes on both sides of the studied rock col­ lapse. the kvarner area is a relatively well-explored and described area compared to other parts of the croatian coast. nevertheless, there is still not enough meaningful evidence to document its geomorphological evolution in detail, especially concerning the age of the tidal notches. in addition, possible tectonic movements and sea level fluctuations in recent times need to be investigated. therefore, the results of a new investigation, deeply rooted in time and space, would be an important step towards a better un­ derstanding of the geomorphological evolution of the studied col­ lapse structures and similar structures on escarpments around the kvarner area. this could significantly change the current re­ construction not only of relief evolution in the kvarner area, but also in other parts of the adriatic channel zone. acknowledgment the authors thank their colleague dr. tvrtko korbar for their useful advice during the preparation of this article. the authors also thank their colleague duje kalajžić for excellent photos using uav technique and for help with terrain analysis using sfm­mvs photogrammetry. funding this research has been partially financed by the university of rijeka (uniri-tehnic-18-97 and uniri-zip-2103-6-22). references benac, č. & juračić, m. (1998): geomorphological indicators of the sea-level changes during upper pleistocene (wuerm) and holocene in the kvarner region.– acta geograph. croat., 33, 27–45. benac, č., juračić, m. & bakran-petricioli, t. (2004): submerged tidal notches in the rijeka bay ne adriatic sea: indicators of relative sea-level change and recent tectonic movements.– marine geol., 212, 21–33. doi: 10.1016/j.mar­ geo.2004.09.002 benac, č., dugonjić, s., arbanas, ž., oštrić, m. & jurak, v. (2009): the origin of instability phenomena along the karst-flysch contacts.– in: vrkljan, i. (ed.): isrm int. symp. rock engineering in difficult ground conditions: soft rock and karst. dubrovnik, october 2009, crc press, boca raton-london-new yorkleiden, 757–761. benac, č., dugonjić, s., vivoda, m., oštrić, m. & arbanas, ž. (2011): a complex landslide in the rječina valley: results of monitoring 1998-2010.– geol. croat., 64/3, 239–249. doi: 104154/gc.2011.20 benjamin, j., rovere, a., fontana, a., furlani, s., vacchi, m., inglis, r.h., galili, e., antonioli, f., sivan, d., miko, s., mourtzas, n., felja, i., meredith-williams, m., goodman-tchernov, b., kolaiti, e., anzidei, m. & gehrels, r. (2017): late quaternary sea-level changes and early human societies in the central and eastern mediterranean basin: an interdisciplinary review.– quat. int., 449, 29–57. doi: 10.1016/j. quaint.2017.06.025 bonaldo, d., bucchignani, e., ricchi, a. & carniel, s. (2017): wind storm­ iness in the adriatic sea in a climate change scenario.– acta adriat., 58/2, 195–208. doi: 10.32582/aa.58.2.1 del ben, a., finetti, i., rebez, a. & slejko, d. (1991): seismicity and seismo­ tectonics at the alps dinarides contact.– boll. di geofisica teorica ad applicata, xxxiii (130–131), 155–176. fonstad, m.a., dietrich, j.t., courville, b.c., jensen, j.l. & carbon­ neau, p.e. (2013): topographic structure from motion: a new development in photogrammetric measurement.– earth surf. process landforms 38/4, 421–430. doi: 10.1002/esp.3366 hgi, 2009. geološka karta republike hrvatske 1:300.000 [geological map of republic of croatia 1:300.000 – in croatian].– hrvatski geološki institut, zagreb. hungr, o., leroueil, s. & picarelli, l. (2013): the varnes classification of landslide types, an update.– landslides 11/2, 1–28. doi: 10.1007/s10346-0130436-y iadanza, c., trigila, a., vittori, e. & serva, l. (2009): landslides in coast­ al areas of italy.– in: violante, c. (ed.): geohazard in rocky coastal areas. spec. publication 322. geological society, london, 121–142. doi: 10.1144/ sp322.5 iaeg (1990): suggested nomenclature for landslides.– bull. iaeg, 41, 13–16. james, m.r. & robson, s. (2012): straightforward reconstruction of 3d surfaces and topography with a camera: accuracy and geoscience application.– j. geophys. res. earth surf., 117(f03017), 1–17. doi: 10.1029/2011jf002289, 2012f030171of17 juračić, m., benac, č., pikelj, k. & ilić, s. (2009): comparison of the vulner­ ability of limestone (karst) and siliciclastic coasts (example from the kvarner area, ne adriatic, croatia).– geomorphology, 107/1–2, 90–99. doi: 10.1016/j.geo­ morph.2007.05.020 korbar, t. (2009): orogenic evolution of the external dinarides in the ne adriatic region: a model constrained by tectonostratigraphy of upper cretaceous to paleo­ gene carbonates.– earth-sci. rev., 96/4, 296–312. doi: 10.1016/j.earsci­ rev.2009.07.004 korbar, t., markušić, s., hasan, o., fuček, l., brunović, d., belić, n., palenik, d. & kastelic, v. (2020): active tectonics in the kvarner region (external dinarides, croatia) – an alternative approach based on new focused ge­ ological mapping, 3d seismological and shallow seismic imaging data.– frontiers in earth sci., 8, 1–21(582797). doi: 10.3389/feart.2020.582797 marinčić, s. & matičec, d. (1991): tektonika i kinematika deformacija na prim­ jeru istre [tectonics and kinematics of deformations, an istrian model – in croa­ tian].– geološki vjesnik, 44, 257–268. markušić, s., stanko, d., korbar, t. & sović, i. (2019): estimation of nearsurface attenuation in the tectonically complex contact area of the northwestern external dinarides and the adriatic foreland.– nat. hazards earth syst. sci., 19, 2701–2714. doi: 10.5194/nhess-19-2701-2019 mihljević, d. (1996). strukturno-geomorfološke značajke i morfotektonski model razvoja gorskog hrpta učke [structural-geomorphological characteristics and morphotectogenetic evolution model of the učka mountain range (croatia) – in croatian].– hrvatski geografski glasnik 58, 33–39. orlić, m. & pasarić, z. (2013): semi-empirical versus process-based sea-level pro­ jections for the twenty-first century.– nat. climat change, 3, 735–738. doi: 10.1038/nclimate1877 g eo lo gi a c ro at ic a geologia croatica 76/3112 penzar, b., penzar i. & orlić, m. (2001): vrijeme i klima hrvatskog jadrana [weather and climate of croatian adriatic – in croatian].– dr. feletar, biblioteka geographica croatica 16, zagreb, 258 p. pirazzoli, p.a. (2005): a review of possible eustatic, isostatic and tectonic contribu­ tions in eight late-holocene sea-level histories from the mediterranean area.– quat. sci. rev., 24, 1989–2001. doi: 10.1016/j.quascirev.2004.06.026 placer, l., vrabec, m. & celarc, b. (2010): the bases for understanding of the nw dinarides and istria peninsula tectonics.– geologija, 53/1, 55–86. doi: 10.5474/geologija.2010.005 ružić, i., marović, i., benac, č. & ilić, s. (2014): coastal cliff geometry derived from structure­from­motion photogrammetry at stara baška, krk island, croatia.– geo-marine letters, 34, 555–565. doi: 10.1007/s00367-014-0380-4 shang, x., zhao, j. & zhang, h. (2019): obtaining high-resolution seabed to­ pography and surface details by co­registration of side­scan sonar and multi­ beam echo sounder images.– remote sensing, 2019/11, 1–21 (1496). doi: 10.3390/rs11121496 www.mdpi.com/journal/ surić, m., korbar, t. & juračić, m. (2014): tectonic constraints on the late pleistocene­holocene relative sea­level change along the north­eastern adriatic coast (croatia).– geomorphology, 220, 93–103. doi: 10.1016/j.geo­ morph.2014.06.001 šikić, d., polšak, a. & magaš, n. (1969): osnovna geološka karta 1:100.000, list labin [basic geological map 1:100.000, labin sheet – in croatian].– institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd. tsimplis, m.n., raicich, f., fenoglio-marc, l., shaw, a.g.p., marcos, m., somot, s, & bergamasco, a. (2012): recent developments in under­ standing sea level rise at the adriatic coasts.– physics and chemistry of the earth parts a/b/c, 40–41, 59–71. doi: 10.1016/j.pce.2009.11.007 weber, j., vrabec, m., pavlovčič-prešeren, p., dixon, t., jiang, y. & stopar, b. (2010): gps-derived motion of the adriatic microplate from istria peninsula and po plain sites, and geodynamic implications.– tectonophysics, 483/3–4, 214–222. doi: 10.1016/j.tecto.2009.09.001 www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction according to the united nations (2024), 55% of the world's population lived in urban areas in 2018 and it is expected to increase to 68% by 2050. a large number of people living in a small, limited urban area has a severe impact on the environment. modern lifestyles lead to significant pollution. urban geochemical mapping provides information on the concentration, dispersion and distribution of potentially toxic elements (ptes) and other pollutants in the urban ecosystem (wong et al., 2006; long & lyons, 2020). such data are substantial for the assessment of contamination and potential environmental and health risks. urban soils are, in the broadest sense, soils that have developed in urban areas. they are exposed to strong anthropogenic influences and play an important role in the ecosystem (o'riordan et al., 2021). urban soils are an ideal reservoir for the storage of ptes, they accumulate them over time and therefore they often have elevated concentrations of potentially toxic elements (wong et al., 2006; šorša et al., 2017). urban geochemical studies conducted as part of the geochemical mapping of cities in different parts of the world aimed to determine the concentration and spatial distribution of ptes and other pollutants in soil or dust. research methods differ from city to city, making it very difficult to correlate the results obtained in different cities (birke & rauch, 2000; glennon et al., 2014; tarvainen et al., 2018). therefore, a european project of the eurogeosurveys geochemistry expert group project (egs-geg) “urban geochemistry in europe – soil, children, health (urge)” was launched to assess the environmental quality of urban topsoil using harmonized geochemical mapping in cities (demetriades & birke, 2015a, b). as part of the urge project, a geochemical survey of the urban soils of the city of sisak and its surroundings was carried out. historical maps as a tool in the interpretation of urban topsoil geochemistry: a case study from the roman city of sisak, croatia ajka pjanić1,*, goran durn2, josip halamić1 1 croatian geological survey, sachsova 2, 10000 zagreb, croatia; (*corresponding author: apjanic@hgi-cgs.hr; jhalamic@hgi-cgs.hr) 2 faculty of mining, geology and petroleum engineering, university in zagreb, pierottijeva 6, zagreb, croatia; (goran.durn@rgn.hr) doi: 10.4154/gc.2025.09 abstract topsoil geochemistry maps of the city of sisak were compared with historical maps to explain the geochemistry of the topsoil. historically, three periods of sisak's development can be distinguished: 1) the celtic and roman period; 2) the medieval period, and 3) the industrial era during the 20th century. comparison of the geochemical maps with the historical maps reveals 1) the accumulation of elements in the soil and their preservation over 2,000 years; 2) the influence of infrastructural interventions on the geochemical composition of the topsoil and 3) the high rate of accumulation of potentially toxic elements in the topsoil due to rapid industrialisation on purely arable land. the geochemical maps of the city of sisak area were generated using descriptive statistics of the concentration of individual elements in the topsoil (šorša & halamić, 2014), as well as using multivariate statistical analyses of the entire set of chemical elements and ph, including factor analysis (šorša et al., 2017) and discriminant analysis (šorša et al., 2018a). interpretation of the obtained geochemical maps considers the geological background, the pedological development and the anthropogenic influence. the geological and pedological influence on soil chemistry was visible on various geochemical maps of the area (pikija, 1987a, b; husnjak, 2012; šorša et al., 2017, 2018a, b, 2023). the anthropogenic influence is permanent and has been over a period of about 2,000 years, having a significant impact on the soil, as can also be seen on geochemical maps (šorša et al., 2017). anthropogenic activities can also be observed on historical maps. the numerous studies in old urban areas have focused on the study of environmental changes over time, landscape evolution through the creation of anthropogenic landforms, urban development under the influence of the geologicalgeomorphological characteristics of the area, and the urban geomorphology of a historical cities (amato et al., 2013, 2017; aucelli et al., 2021; mandarino et al., 2021). the aim of this study was to present the use and significance of historical maps for the interpretation and cartographic representation of geochemical mapping data of topsoil in the cities. 2. materials and methods 2.1. description of the study area sisak is a city in central croatia at 45°29' n and 16°20' e (fig. 1). the wider surroundings of sisak are lowlands with a groundwater table between 2 and 4 m below the surface. the deposits consist mainly of fine-grained quaternary alluvial sediments and loess. these are carbonate clastic sediments of article history: manuscript received: december 10, 2024 revised manuscript accepted: march 6, 2025 available online: june 30, 2025 keywords: roman siscia, geochemical maps, historical maps, ptes 2025 | 78/2 | 141–149 | 9 figs. | mailto:apjanic@hgi-cgs.hr mailto:jhalamic@hgi-cgs.hr mailto:goran.durn@rgn.hr g eo lo gi a c ro at ic a 142 geologia croatica 78/2 the sava river in the east, siliciclastic sediments of the kupa and odra rivers in the west and north, and loess deposits in the central part, within the large meander of the kupa river (pikija, 1987a, b). the urban part of the study area is dominated by technogenic soils (urban soils), while in the rural part of the study area hydromorphic soils, mainly gley soils prevail (husnjak, 2012; šorša et al., 2023). the climate in sisak is a “moderately warm rainy climate, without extreme dry periods” (lisac & herić-nekić, 1995). the average annual precipitation is 872 mm and most of it falls during the warm season. the study area includes the urban part of the city of sisak and the adjacent rural surroundings (fig. 1). 2.2. development of the city of sisak there are three important periods in the development of the city of sisak that have had the most influence on the type and concentration of ptes in the topsoil of the study area: 2.2.1. period 1 – the celtic and roman period (the ancient settlements of segestica and siscia) the development of settlements in the floodplains of the kupa, sava and odra rivers began due to their favourable location. it was an important transportation hub between pannonia and dalmatia as well as between the roman empire and the east. the celts most probably arrived in this area in the iv century bc and founded the settlement of segestica (segestika) on the right bank of the kupa river, together with the local illyrian population. in the 1st century bc, the romans conquered the area of sisak and founded the settlement of siscia on the left bank of the kupa river (fig. 2a, b). over time, segestica and siscia were united (slukan altić, 2004) and therefore, the designation siscia is used in this paper for both settlements. under the influence of the celtic tradition, the first production and sale of metal in the sisak region was recorded in segestica. in 262 ad, mints, for minting money for the entire roman empire, were established in siscia, which were active for over 140 years (buzov, 2009). 2.2.2. period 2 – the medieval period during the middle ages, the inhabitants of the sisak region were mainly engaged in agriculture. the city of sisak was located on the boundary with the ottoman empire. it was more of a village than a city (fig. 2c). the entire present-day old part of the city of sisak (the former ancient siscia) was surrounded by the sisak stream (sisački potok), which is marked on the historical map as alter stadt graben (fig. 2b). at the end of the 18th and in the 19th century, as part of urban infrastructural development, water bodies were also managed which includes the filling of the alter stadt graben in 1876. 2.2.3. period 3 – the industrial era during the 20th century due to intensive industrialization in the 1950s, sisak became one of the more powerful industrial cities in the former yugoslavia. the most important branches of industry were heavy industry (metallurgy, refinery, chemicals, textiles, food production and, to a lesser extent, the wood processing industry). the most intensive industrial development took place in the 1970s, which began to stagnate in the 1980s and has now almost disappeared. the heavy industry facilities were mainly located in the south in the newly developed part of the city of sisak (fig. 2d, e). 2.3. sampling, chemical analyses and quality control sampling was carried out in accordance with the urge manual (demetriades & birke, 2015b). a total of 144 topsoil composite samples and 7 field duplicates were collected. one composite sample consisted of five subsamples taken at the corners and in the centre of a 2 × 2 m square. the sampling figure 1. geographical location of the research area. g eologia c roatica 143pjanić et al.: historical maps as a tool in the interpretation of urban topsoil geochemistry: a case study from the roman city of sisak, croatia grid was 0.5 × 0.5 km in the urban and industrialized areas and 1 × 1 km in the adjacent rural areas covering the entire area of sisak (≈ 65 km2). samples were analysed for 53 elements using icp ms. quality control was performed both in the field and in the laboratory. a detailed description of the sampling and laboratory analyses as well as the quality control procedures for topsoil samples was explained in other publications (šorša et al., 2017; šorša et al., 2018a, b). 2.4. data treatment and presentation 2.4.1. historical maps historical maps are a valuable tool for understanding the urbanisation process of cities in the past. these maps are often very detailed and highlight important features such as city walls, rivers, channels, roads, railroads, factories, etc. the city of sisak was first recorded on the two most famous medieval maps from the 13th century, the ebstorf map from ebstorf abbey and the hereford mappa mundi from hereford (slukan altić, 2003; lolić, 2023). since sisak has belonged to different states during its long existence, the cartographic documentation is kept in various institutions such as the regional cadastral office in sisak, the chapter archive in zagreb, the war archive in vienna, the university library in bologna, and the national library in budapest (slukan altić, 2004; lolić, 2023). the overview of the collection of historical cartographic records of sisak has been published in several books and articles (slukan altić, 2004; lolić, 2023). the historical maps of the city of sisak have recorded different periods in the city's past: the ancient segestica and siscia, the transportation network, changes in infrastructure, changes in hydrography, urban and industrial development. the historical maps of sisak show the human fingerprint on the past urban landscapes of the city and were therefore a valuable tool for understanding the topsoil geochemical maps. 2.4.2. geochemical maps the geochemical maps of the single elements were created using two techniques: as dot maps and inverse distance weighting (idw) maps. in the dot maps technique, a point symbol is drawn at the sampling sites to emphasise the concentration at that point. the symbol is a dark grey filled circle that increases in size as the class increases. the class limits for dot maps are represented by the 5th, 10th, 25th, 50th, 75th, 90th and 98th perfigure 2. a) remnants of the roman siscia on the plan of ferdinando marsigli dating from 1726 (after slukan altić, 2004); b) hydrographic map of the sisak area with the siscia (alte stadt sissek) and the kontroba trench (alte stadt graben) from 1783 (cartographic collection of the war archives in vienna, after slukan altić, 2004); c) detail of the military (dorf neu sziszek) and old sisak (dorf alt sziszek) on the plan by ignjat pongrac from 1793 (cartographic collection of the state archive in zagreb; slukan altić, 2004); d) city of sisak on the map from 1901 (cartographic collection of the state archives in zagreb); e) on the urban plan from 2002 (gup, 2002). g eo lo gi a c ro at ic a 144 geologia croatica 78/2 centiles. this is the most accurate technique for visualising the spatial distribution of elements in urban areas. to make the geochemical maps clearer and more user-friendly, additional maps were created with the same data as the dot maps as their “background”. the idw method was used to generate the “background maps” and it was chosen because of the heterogeneity of the topsoil in the urban area, which is the reason for the large variability of the concentration values at the sampling sites. the idw method emphasises the value at a single site. the class limits for idw maps were every two percentiles. the coloured surface layer was generated by idw interpolation with a moving average window cell size of 600 m radius, a weighting power of 2, and the nearest neighbour function to include at least 3 sampling sites. the final geochemical maps for each element are shown as growing grey dark dots overlaid on a coloured surface map. the multi-element geochemical maps were created using the kriging technique. this method was chosen for the visualisation of the factor values in order to highlight regional trends in the study area. a continuous colour-scale with 50 gradations from dark blue (lowest class) to red (highest class) was used for presenting single element “background” and multi-element geochemical maps. the projection of the maps is wgs 1984. all data collected in the study, such as topsoil sample analysis results, fieldwork records, topographic, land use, geological, pedological and historical maps, are managed in arcgis ver. 10.2.1 from esri. the geochemical maps were created using the geostatistical analyst extension of this software. the statistical processing of the analytical data for the maps was prepared using the ibm spss statistics software package. 3. results and discussion the interpretation of geochemical maps of the spatial distribution of single elements and of multi-element maps as a result of statistical processing is related to the lithological and pedological background and the anthropogenic influence. however, some geochemical phenomena, such as unexpected higher concentration of elements or associations of elements in certain urban areas, cannot be explained using the geological and pedological maps alone, but only with the input from the historical maps. 3.1. period 1 – the celtic and roman period geochemical maps can indicate the long-lasting historical development of the area. since the cities were built in ancient times, traces of some elements such as au, ag, cu, pb were accumulated in the urban soils as indicated by their increased concentrations in the soil in the area. according to the geochemical map of gold in topsoil in the city of sisak, the measured concentrations of au in the soils of the entire urban area of sisak are not significant (fig. 3; fig. 4 in šorša et al., 2017). however, the distribution of this element in the analysed samples provide some interesting phenomenon for the area. the highest concentrations and extreme values of au were measured in ancient siscia. these elevated au concentrations in the soil indicate an anthropogenic input during the past two thousand years of human activity. the anomalous concentrations in the southern industrial zone are probably related to industrial activities (ironworks, refinery). the geochemical map of the spatial distribution of copper in the topsoil layer shows an area with elevated concentrations figure 3. a geochemical map of the spatial distribution of au in sisak topsoil. g eologia c roatica 145pjanić et al.: historical maps as a tool in the interpretation of urban topsoil geochemistry: a case study from the roman city of sisak, croatia of cu in the soil in the ancient settlement of siscia (fig. 2a–c). these values are the result of the anthropogenic input of cu into the soil at that time (smelters and mints, jewellery and various household and craft items). to the east of ancient siscia, cu levels are also elevated in the vicinity of the chemical plant, which can be linked to the production of pesticides. other areas with elevated cu levels are located along roads and railway lines and to the south in the industrial zone (fig. 4). in addition to the industrial facilities, cu was dispersed by the wind in the surrounding settlements and on agricultural land downwind on the left bank of the sava river. the map of the spatial distribution of lead in the study area shows that the pb is predominantly of anthropogenic origin. the first area with extreme and anomalous pb concentrations is located in the urban complex comprising the area of the siscia (fig. 2a, b). as siscia was a centre for the minting of coins for the needs of the roman empire, pb was released into the environment during the smelting of ores and the minting of coins. lead was also a widely used metal in ancient times for water pipes (fig. 5) and for many other commonly used items, so the high concentrations of pb in the topsoil are related to this period and only a small part is more recent, e.g. along roads due to the combustion of fuel in vehicles. another area with an elevated pb content in the topsoil is located in the southern industrial zone, then it was dispersed by the wind to the surrounding settlements and to the agricultural areas on the left bank of the sava river (fig. 6). due to the largest factor score associated with the mints, factor 6 (fa6) can be interpreted as an anthropogenic factor: roman mints (šorša et al., 2017). multi-element geochemical maps show groups of elements au, ag, hg, pb, bi and p associated with ancient siscia (fig. 7). copper coins with ag or au coating were minted in smelters and mints throughout the roman empire, also in siscia. the method of coating coins involved the use of mercury (ingo et al., 2006). the fa6 factor score is also elevated in the southern industrial zone due to heavy industry production. 3.2. period 2 – the medieval period the interpretation of the geochemical maps of the spatial distribution of cr, ni, co, fe, v, ce, ga, la, nb, rb and tl (šorša & halamić, 2014) was questionable in siscia. as expected, the concentrations of these elements were elevated in the industrial zone in the south, in the alluvium of the kupa and odra rivers, but concentrations were also elevated around figure 4. a geochemical map of the spatial distribution of cu in sisak topsoil (modified from šorša et al., 2018b). figure 5. a lead water pipe from the roman period kept in the city museum in sisak (photo: josip halamić). g eo lo gi a c ro at ic a 146 geologia croatica 78/2 figure 6. a geochemical map of the spatial distribution of pb in sisak topsoil (modified from šorša et al., 2018b). figure 7. a geochemical map of the score of the factor analyses in sisak topsoil – anthropogenic factor 6 – roman mints (modified from šorša et al., 2017). g eologia c roatica 147pjanić et al.: historical maps as a tool in the interpretation of urban topsoil geochemistry: a case study from the roman city of sisak, croatia tions in the topsoil along the old roads and the railway can be interpreted with the help of historical maps (čakširan, 2011; fig. 2d), on which we can see the beginning of the development of industry in the late 19th and early 20th century. the map in figure 2d is from 1901 and on it the future southern industrial area is the village of caprag without industrial facilities. on the 2002 map (gup, 2002; fig. 2e), the entire area is an industrial complex with settlements for the workforce in between. the elements with high factor loading values in fa1 are used in the metallurgy and chemical industries and released by the combustion of oil, fuel oil, coal and waste, then by exhaust fumes from vehicles, tyres and brakes on roads and railways, domestic waste, and sewage etc. as industrial development was intensive from the 1950s to the 1980s, the accumulation of trace elements in the topsoil is considerable. 4. conclusions the sisak area is scientifically notable due to its unique development over 2,000 years. three key phases of sisak's development were identified: 1) the celtic and roman period; 2) the medieval period; and 3) the modern industrial era. the origin of potentially toxic elements in the soil is clear since the roman siscia (north) and the modern industry (south) occupy different geographic areas. the city’s medieval phase had minimal anthropogenic influence. this allowed the tracing of: 1) the accumulation of elements in the soil and their preservation from the roman period to the present; 2) the impact of infrastructural changes on topsoil composition; and 3) the rate of element build up due to rapid industrialization on formerly arable land. a satisfying interpretation of the concentration and spatial distribution of chemical elements on geochemical maps in siscia. the satisfactory explanation for this was provided by the historical hydrographic maps, which showed the existence of the old sisak stream around roman siscia, labelled on the map as alter stadt graben (fig. 2b, c), which was connected to the kupa river and has the same alluvial parent material. although the stream was filled in, 130 years ago, its impact on the geochemistry of the topsoil layer is still recognisable. elevated levels of cr were measured in soils formed on the alluvial sediments of the kupa and oder rivers, which are of geogenic origin due to the weathering of basic and ultrabasic magmatic rocks in the hinterland (fig. 8). the high cr levels in the southern industrial zone and the surrounding urban and agricultural areas are the result of anthropogenic pollution. 3.3. period 3 – the industrial era during the 20th century factor 1 (fa1) is an anthropogenic factor with the highest factor score values of mo, zn, w, sn, sb, cd, mn, cu, pb, cr, fe, ba, ni, ti, na, bi, s, ag, in, as, u, hg and v in the southern industrial zone. the elements (variables) associated with anthropogenic pollution from heavy industry have the highest factor loading, and therefore fa1 can be interpreted as heavy industry. the highest values are located in the vicinity of the ironworks, refinery, the thermal power plant, the surrounding settlements and the agricultural land in the north-east, in the favoured wind direction of the industrial facilities (šorša et al., 2018b; fig. 9). the value of the factor load is also increased to the north of sisak (ancient siscia), along the old road and railway, then along the kupa river and in the southeast in the river port on the sava river. in the ancient part of sisak, ptes have accumulated in the soil due to the long-term existence of settlement (over 2,000 years) (fig. 2a–e). elevated concentrafigure 8. a geochemical map of the spatial distribution of cr in sisak topsoil. g eo lo gi a c ro at ic a 148 geologia croatica 78/2 urban areas can be obtained not only using geological and pedological maps, but also with the help of historical maps. acknowledgement this study was financially supported by the ministry of science, education and sports, republic of croatia – scientific project: the basic geochemical map of croatia, number 1811811096-1181. we are grateful to associate editor gevorg tepanosyan and the anonymous reviewers for their thorough evaluations, which significantly improved the manuscript. references amato, v., aucelli, p.p.c., capozzi, a., de benedittis, g., pappone, g. & rosskopf, c.m. (2013): environmental changes in the boiano intramontane basin (molise, italy) since the times of ancient bovianum (ivth century bc).– alpine and mediterranean quaternary, 26/1, 15–29. amato, v., aucelli, p.p.c., bracone, v., cesarano, m. & rosskopf, c.m. (2017): long-term landscape evolution of the molise sector of the central-southern apennines, italy.– geologica carpathica, 68/1, 29–42. https://doi.org/10.1515/geoca-2017-0003 aucelli, p.p.c., valente, e., di paola, g., amato, v., cesarano, m., cozzolino, m., pappone, g., scorpio v. & rosskopf, c.m. (2021): the influence of the geological–geomorphological setting on human settlements and historical urban development: the case study figure 9. a geochemical map of the score of the factor analyses in sisak topsoil – anthropogenic factor 1 – heavy industry (modified from šorša et al., 2017). of isernia (southern italy).– journal of maps, 17/4, 141–150. https://doi. org/10.1080/17445647.2020.1794989 birke, m. & rauch, u. (2000): urban geochemistry: investigations in the berlin metropolitan area.– environmental geochemistry and health, 22/3, 233–248. https://doi.org/10.1023/a:1026554308673 buzov, m. (2009): siscijska kovnica [the siscian mint – in croatian].– in: cambi, n. (ed.): dioklecijan, tetrarhija i dioklecijanova palača o 1700. obljetnici postojanja, književni krug, split, 621–645. čakširan, v. (2011): industrijska baština grada siska [industrial heritage of the city of sisak – in croatian].– gradski muzej sisak, sisak. demetriades, a. & birke, m. (2015a): urban topsoil geochemical mapping manual (urge ii).– eurogeosurveys, brussels, 52 p. demetriades, a. & birke, m. (2015b): urban geochemical mapping manual: sampling, sample preparation, laboratory analysis, quality control check, statistical processing and map plotting.– eurogeosurveys, brussels, 162 p. glennon, m.m., harris, p., ottesen, r.t., scanlon, r.p. & o’connor, p.j. (2014): the dublin surge project: geochemical baseline for heavy metals in topsoils and spatial correlation with historical industry in dublin, ireland.– environmental geochemistry and health, 36, 235–254. https://doi.org/10.1007/s10653-013-9561-8 gup (2002): generalni urbanistički plan grada siska [general urban plan of the city of sisak – in croatian].– izvršitelj: centar za prostorno uređenje i arhikteturu d.o.o. zagreb. naručitelj: rh, sisačko-moslavačka županija, grad sisak, sisak, 207 p. g eologia c roatica 149pjanić et al.: historical maps as a tool in the interpretation of urban topsoil geochemistry: a case study from the roman city of sisak, croatia husnjak, s. (2012): kompilirana pedološka karta grada siska i okolice [compiled pedological map of the city of sisak and its surroundings – in croatian].– unpubl. report, archive of the croatian geological survey, zagreb. ingo, g.m., balbi, s., de caro, s., fragalà, i., riccucci, c. & bultrini, g. (2006): microchemical investigation of greek and roman silverand gold-plated coins: coating techniques and corrosion mechanisms.– applied physics a, 83, 623–629. http://doi.org/10.1007/ s00339-006-3536-x lisac, i. & herić-nekić, s. (1995): prilog poznavanju klime siska [contribution to knowledge about the climate of sisak – in croatian].– hrvatski meteorološki časopis, 30, 79–99. lolić, t. (2023): urbanisation of roman siscia: interpretation of historical and modern maps, drawings and plans.– archaeopress roman archaeology 89, oxford, 200 p. long, t.d. & lyons, w.b. (2020): urban geochemistry.– encyclopedia of geology, 2nd edition. https://doi.org/10.1016/b978-0-12-409548-9.125266 mandarino, a., luino, f., turconi, l. & faccini, f. (2021): urban geomorphology of a historical city straddling the tanaro river (alessandria, nw italy).– journal of maps, 17/4, 29-41. https://doi.org/10.1080/1 7445647.2020.1746420 o’riordan, r., davies, j., stevens, c., quinton, j.n. & boyko, ch. (2021): the ecosystem services of urban soils: a review.– geoderma, 395. 115076. https://doi.org/10.1016/j.geoderma.2021.115076 pikija, m. (1987a): osnovna geološka karta sfrj 1:100 000, list sisak [basic geological map of sfrj 1:100000, sisak sheet – in croatian].– geol. zavod zagreb, savezni geol. zavod, beograd. pikija, m. (1987b): osnovna geološka karta sfrj 1:100 000. tumač za list sisak [basic geological map of the sfrj 1:100000, explantory notes for sisak sheet – in croatian with english summary].– geol. zavod zagreb, savezni geol. zavod, beograd, 55 p. slukan altić, m. (2003): povijesna kartografija – kartografski izvori u povijesnim znanostima [historical cartography. cartographic sources in historical sciences – in croatian].– meridijani, zagreb. 495 p. slukan altić, m. (2004): povijesni atlas gradova: sisak [historical – towns’ atlas: sisak – in croatian].– sisak state archive & croatian state archive, zagreb, 241 p. šorša, a. & halamić, j. (2014): geochemical atlas of sisak.– public library vlado gotovac sisak, city museum sisak and croatian geological survey, sisak-zagreb, 200 p. šorša, a., durn, g., halamić, j., husnjak, s., garašić, v. & mileusnić, m. (2017): urban geochemistry: sisak in croatia, a long-lasting historical, urban and industrial city.– geochemistry: exploration, environment, analysis, 17/2, 159-163. https://doi.org/10.1144/geochem2015-395 šorša, a., peh, z. & halamić, j. (2018a): geochemical mapping the urban and industrial legacy of sisak, croatia, using discriminant function analysis of topsoil chemical data.– journal of geochemical exploration, 187, 155–167. https://doi.org/10.1016/j.gexplo.2017.07.014 šorša, a., miler, m., gosar, m. & halamić, j. (2018b): follow-up geochemical studies and mineralogical investigations by scanning electron microscopy/energy dispersive spectroscopy (sem/eds) of soil samples from the industrial zone of sisak, croatia.– journal of geochemical exploration, 187, 168–183. ht tps://doi.org/10.1016/j. gexplo.2017.07.015 šorša, a., durn, g., grizelj, a., halamić, j. & prša gazilj, l. (2023): comparison of urban and rural soils based on speciation of heavy metals by bcr sequential extraction procedure: a case study in the historical and industrial city of sisak, croatia.– geologia croatica, 76/2, 87–103. https://doi.org./10.4154/gc.2023.06 tarvainen, t., ladenberger, a., snöälv, j., jarvaa, j., anderssonb, m. & eklunda, m. (2018): urban soil geochemistry of two nordic towns: hämeenlinna and karlstad.– journal of geochemical exploration, 187, 34–56. https://doi.org/10.1016/j.gexplo.2017.07.018 wong, c.s.c., li, x. & thornton, i. (2006): urban environmental geochemistry of trace metals-review.– environmental pollution, 142, 1–16. https://doi.org/10.1016/j.envpol.2005.09.004 web source: united nations (2024): department of economic and social affairs population dynamics, world urbanization prospects 2024. available at: https://population.un.org/wpp/. accessed on: december 6th 2024. https://doi.org/10.1144/geochem2015-395 https://doi.org/10.1144/geochem2015-395 https://doi.org/10.1016/j.envpol.2005.09.004 https://population.un.org/wpp/ www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2024 | 77/3 | 269–289 | 7 figs. | 5 tabs. | 1 supplement | article history: manuscript received: april 15, 2024 revised manuscript accepted: july 22, 2024 available online: october 28, 2024 keywords: pottery, raw materials, archaeometry, provenience 1. introduction the production process for each ceramic object starts with the selection of suitable raw materials. that procedure is very complex and commonly influenced by various cultural factors rather than it is just being a technologically determined choice (rice, 1987). in addition, raw materials (clayey and tempering material), as the essential elements of each ceramic product, directly affect the production process and properties of the final product (rice, 1987; velde & druc, 1999). their examination is therefore of great importance for understanding the technology of ancient societies, especially in the context of one of the oldest crafts in human history, pottery. from a materials science perspective, the properties of raw materials in ceramic production and the methods of processing result in a specific artefact structure and chemical composition (tite, 1999). from an archaeological perspective, these properties are indicative of a particular technological tradition, or material culture integral to past societies. the research approach, encompassing ancient materials science, facilitates the investigation of pottery technologies and enhances understanding of the selection of specific raw materials. simultaneously, the results can offer further insights into the use, exchange, and distribution of these products (tite, 1999; sillar & tite, 2000). tracing the origin of raw materials used for the production of ancient ceramics: a case study of multi-period archaeological sites in the turopolje area (continental croatia) natali neral1,*, andreja kudelić1, ana maričić2 and marta mileusnić2 1 institute of archaeology, jurjevska street 15, 10000 zagreb, croatia; (*corresponding author: nneral@iarh.hr) 2 university of zagreb, faculty of mining, geology and petroleum engineering, department of mineralogy, petrology and mineral resources, pierottijeva 6, 10000 zagreb, croatia doi: 10.4154/gc.2024.18 abstract the selection of raw materials for ancient pottery production was influenced by a variety of technological and cultural factors, underscoring the importance of characterising these materials to understand the technology of ancient societies. this research examines ancient ceramics from two multi-period archaeological sites: staro čiče-gradišće (neolithic, copper age, copper/early bronze age, early bronze age, late bronze age, roman period, and late mediaeval period) and kurilovec-belinščica (early bronze age and middle/late bronze age), alongside potential clayey raw materials collected near these settlements. using a multi-analytical approach (optical microscopy, x-ray powder diffraction, mass and emission spectrometry, and laser granulometry), the research aims to determine the characteristics of the paste recipes (raw clay and tempers) and to examine the type and provenience of the raw materials used for ancient pottery production over different periods of the past (from the neolithic to the late mediaeval period). the results showed that ancient potters preferred to use moderately plastic, sandy clay, while bronze age potters often used highly plastic clay. potters utilised various non-plastic tempering materials, such as sands and gravels, grog, and mollusc shells, with their choice being influenced by the need to enhance technological properties as well as by regional and culturally determined pottery traditions. most of the ceramics are of local origin, made from easily available raw materials that represent flood sedi ments of the nearby sava river. however, non-local materials were detected in neolithic samples, indicating the presence of exchange networks among those communities. following this approach, this paper aims to provide a detailed study of the textural, compositional and technological properties of the raw materials potentially used for ceramic vessel production over a long period of time. spatially, the research is conducted in the area of turopolje, near the sava river, which is located in the southwestern edge of the pannonian plain, in croatia. it is a strategically important, but often neglected border area between two geographical and geological zones, a frequent contact zone of different sociocultural traditions in the past. for these reasons, the regionally significant archaeological site staro čiče-gradišće was chosen as a main case study. since it is a multi-period site (neolithic, copper age, copper/early bronze age, early bronze age, late bronze age, roman period, and late mediaeval period), the research questions are focused on the characterization of ancient recipes, determining the differences in type and processing of the raw material used for pottery making between the fifth millennium bc and the first half of the second millennium ad. to appropriately discuss the selection of raw materials and the production and exchange of ceramics within past com munities, it is necessary to collect potential clayey materials from the surrounding area alongside analysing the archaeo logical ceramics. this approach enables the investigation of the origin and availability of resources, indirectly shedding mailto:nneral@iarh.hr g eo lo gi a c ro at ic a 270 geologia croatica 77/3 light on the interactions between past communities and their immediate environment. in contrast to the numerous studies focused on the provenance of the pottery raw materials (e.g. maritan et al., 2005; iordanidis et al., 2009; papachristodoulou et al., 2010; carloni et al., 2021; spataro, 2011; ionescu et al., 2011; ratto et al., 2015; santos rodrigues et al., 2015; amicone et al., 2020; sterba et al., 2020; maritan et al., 2021), fewer are conducted on both the ceramics and the raw materials collected in the nearby environment (e.g. žibrat gašparič, 2004; belfiore et al., 2014; andaloro et al., 2011; michelaki et al., 2014; šarić et al., 2018; gonzález et al., 2018; kałaska et al., 2020; beltrame et al., 2021). in croatia, such research is still very rare (mange & bezeczky, 2006; šegvić et al., 2012; maritan et al., 2019; miše et al., 2020; miše & quinn, 2022) whereas only several studies examine the potential raw materials collected near the place of production (kudelić et al., 2018; miše et al., 2019). these studies mainly consider a single archaeological site or specific period, whereas only one recent study provided an insight into the raw materials preferences throughout different periods of the past (neral et al., 2023). to that extent, this research represents a significant step forward in studying the variability of ancient potters' recipes, focusing on multi-period archaeological sites, which will enable the monitoring of changes in the use of resources within the immediate landscape. the study will therefore seek to answer the following questions: was pottery production exclusively local during all periods of the past? why were specific raw materials chosen? was the choice influenced by the availability and characteristics of the immediate environment, the optimisation of technological solutions, or cultural factors? to answer these questions, a multi-analytical approach, including optical microscopy, x-ray powder diffraction, mass and emission spectrometry, and laser granulometry, was applied to both the ceramics and clayey samples. among these, the optical microscopy of thin sections represents an essential method for determining the ceramic fabric groups and characterizing the potential raw materials, by making fired clay briquettes of the clayey material collected in the vicinity of the sites. in addition, geochemical analysis provides detailed compositional patterns of major, minor, trace and rare earth elements (ree) that enable identification of the specific raw material sources and facilitate differentiation between locally produced and imported ceramics. therefore, to enhance the understanding of raw material selection processes and ensure a more robust dataset for considering their provenance and distribution over time, the research incorporates geochemical data from ceramic sherds and clay samples from the nearby kurilovec-belinščica site (early bronze age and middle/late bronze age). accordingly, this study presents the results of integrated mineralogical, petrographic, and chemical analyses of various ceramic assemblages from multi-period archaeological sites, alongside clayey sediments gathered in their proximity. 2. geological and archaeological setting 2.1. geological setting the turopolje region is situated in the central part of the republic of croatia (fig. 1). the area of approximately 600 figure 1. the location and geological map of the turopolje region with locations of investigated archaeological sites (modified after: pikija, 1987b; basch, 1981; kudelić & sirovica, 2022). g eologia c roatica 271neral et al.: tracing the origin of raw materials used for the production of ancient ceramics: a case study of multi-period archaeological sites ... km2 is bordered by the two rivers: the sava in the northern and the kupa in the southern part. geologically, the turopolje is situated in the southwestern part of the pannonian basin system (pbs), a depositional area that palaeogeographically belonged to the central paratethys (rögl & steininger, 1984; pavelić, 2001; kurečić, 2017). the relief of turopolje is represented by two main morphographic types: the sava river valley and vukomeričke gorice, the hilly relief of smaller horsts formed by uplift along the dinaric extension fault (velić, 1983). the most common and the oldest deposits that outcrop along the horsts are the viviparus beds composed mostly of sand, gravel and clay sediments of pliocene age. the youngest, plio-quaternary f luvial-lacustrine sediments composed of the alternation of gravel, sand and clay deposits and pleistocene loess sediments are less frequent (šikić et al., 1978, 1979; pikija, 1987a, 1987b; kurečić, 2017). the alluvial sava river valley consists mainly of quaternary deposits, and is divided into three lithostratigraphic units. the oldest lithostratigraphic unit comprises gravels, sands, and clays whereas the middle one consists of loess deposits, fine clayey silts with interlayers of sands and gravels and, sporadically, peat and swamp sediments. the youngest unit is composed of gravels, sands, and silty clays (šimunić & basch, 1975; šikić et al., 1978, 1979; basch, 1983; pikija, 1987a, 1987b; barudžija et al., 2020). the multiperiod archaeological sites staro čiče-gradišće and kurilovecbelinščica are situated on fine-grained, floodplain sediments of the sava river formed as the result of occasional floods occurring in the wider area of the valley. the thickness of floodplain sediments in the longitudinal profile increases from west to east, while in the transverse profile, it decreases as it approaches the sava riverbed. flood sediments consist of finegrained unconsolidated deposits like gravels, sands, sandyclays or clayey silts with a transition to silty clays (basch, 1981, 1983). these deposits are mainly of carbonate origin, composed of limestone and dolomite, while quartz, siliciclastic sediments and fragments of siliciclastic rocks are subordinate (crnković & bušić, 1970; barudžija et al., 2020). 2.2. archaeological setting the turopolje is a cultural and historical region situated on the south-western fringe of the pannonian plain. it is primarily a marshy area located directly along the course of the sava river on the edge of the contact zone with the adriatic or karst region. this strategically important area and the crossroads of communication routes were the reason for the establishment of the settlement in not always ideal living conditions. this paper presents the ceramic assemblages from two archaeological sites. staro čiče-gradišće is one of the sites in the lowland of turopolje (fig. 1) and was almost continuously inhabited from the neolithic to the late middle ages. this makes this archaeological site unique in the wider area of continental croatia and the only site of the tell type. the archaeological excavations conducted back in the 80s (durman, 1983; težak-gregl & vojvoda, 1987) brought to light a stratified sequence with repeated layers of occupation phases dated to the neolithic, cooper age, early and late phase of the bronze age (balen-letunić, 1996; kudelić & sirovica, 2022), late antiquity and the late medieval period. in contrast, the nearby kurilovec-belinščica site (fig. 1) is a multi-period, primarily bronze age site with a sporadic occurrence of roman-period and modern-period archaeological remains. the most intensive activities were recorded during the middle and early phases of the late bronze age, with settlement remains dated to between the 15th and 13th centuries bc (kudelić, 2016; kudelić & sirovica, 2022). however, modest remains and very fragmented pottery dated to the early bronze age period between the middle of the 22nd to the middle of the 20th century bc were also discovered at the site (kudelić & sirovica, 2022). the positions of these sites were strategic, and probably played a key role, especially the site of staro čiče-gradišće, in the cultural and economic dynamics between the population in the border area between pannonia, the alps and the eastern adriatic. 3. materials and methods 3.1. archaeological ceramics investigating pottery from the site of staro čiče-gradišće, over 2,000 fragments, mostly prehistoric, were examined macroscopically. based on macroscopically determined groups of ceramic fabrics, 40 representative samples were selected for archaeometric analysis covering all the periods represented (table 1, fig. 2). to obtain a more reliable geochemical comparison of ceramics from the turopolje region, the research includes geochemical data of ceramic sherds from the bronze age site kurilovec-belinščica (14 samples, table 1, fig. 2) the mineralogical and petrographic characteristics of which were previously published in kudelić et al. (2018). 3.2. clayey samples field sampling of potential clayey raw materials was conducted in the vicinity of the staro čiče-gradišće site and was focused on watercourses that are common sources of clayey sediments. samples were collected in a zone up to 500 m away from the archaeological site. a total of 10 samples were collected in seven locations using a hand auger from 0.5 to 1.4 m in depth. in order to obtain a more reliable data set of geochemical compositions, the research also includes three clayey samples collected in the vicinity of the kurilovec-belinščica site, the mineralogical and petrographic characteristics of which were previously published (kudelić et al., 2018). 3.3. analytical methods to examine paste recipes and the characteristics and provenance of the raw materials used in ancient pottery production, the ceramic and clayey samples were analysed using the following methods: ceramic petrography, x-ray powder diffraction (xrpd), inductively coupled plasmamass spectrometry (icp-ms) and emission spectrometry (icp-es) and laser granulometry. analytical methods were conducted at the university of zagreb, faculty of mining, geology and petroleum engineering and at the institute of archaeology in zagreb. g eo lo gi a c ro at ic a 272 geologia croatica 77/3 the clayey samples were moulded in small briquettes, dried at room temperature and fired in a laboratory kiln at 650 °c for one hour with a 30-minute soaking period to investigate the characteristics of the collected clayey samples and obtain a relevant comparison with clayey materials found in archaeological ceramics. sample 101 was unsuitable for modelling clayey briquette due to its high sand content, which prevents proper briquette formation. the plasticity of the clayey samples was measured on-site, by simulating the conditions of actual processing and by manual modelling of a clay roller and observing deformation by bending force (plasticity range: no plasticity, low, moderate, and high plasticity). ceramic sherds and fired clay briquettes were cut vertically and prepared as thin sections for optical microscopy. the samples were studied under a polarizing microscope zeiss axiolab 5 in transmitted light. the petrographic analysis of ceramics included the determination of the colour of the matrix, its texture, optical activity, mineral composition, presence of natural and anthropogenic inclusions, voids, and pores. the fabric groups were determined according to the mineralogical composition, amount, size and sorting of the inclusions in the matrix (pcrg, 2010; quinn, 2013) which indicates different types of clayey raw materials. fabric subgroups were determined according to the type, size, amount, roundness and bior polymodal grain size distribution indicating temper materials. for the x-ray powder diffraction (xrpd, table 1), approximately five grams of the archaeological ceramics and clayey samples were crushed to a powder fraction using retsch vibratory disc mill rs 200. analysis was conducted on a panalytical empyrean diffractometer equipped with cu-kα radiation. scan settings were 3–70 °2θ on the rotating sample stage, 0.013 °2θ step size, 80 s per step. mineral identification was conducted according to moore & reynolds (1997) using panalytical x’pert highscore software with standardized powder diffraction files of the international centre for diffraction data (icdd). the semiquantitative mineralogical composition was estimated using the reference intensity ratio (rir) method (snyder, 1992), data obtained by calcimetry and diffraction maxima of the reference materials (quartz). in order to determine the type of the clay minerals, the < 2 µm fraction of each clayey sample was isolated from the bulk samples and recorded after the following treatments: k and mg saturation, ethylene glycol solvation, dimethyl sulfoxide solvation, heating to 350 °c and 650 °c. grain size distribution (in volumetric fractions) of clayey samples was estimated using a laser granulometer malvern panalytical mastersizer 3000 particle size analyzer with hydro ev unit and < 5 % obscuration. due to the volumetric fraction measurement and non-spherical particle shapes, the results of this method are not comparable to those based on mass fractions. to examine the shrinkage, 50 g of each clayey sample collected on site was modelled in a roller approximately 7 x 2 cm in size and left to dry at room temperature. the length and diameter of each roller were measured until they were completely dry. relative shrinkage (%) was assessed by the table 1. list of pottery samples from the staro čiče-gradišće and kurilovecbelinščica sites selected for analytical methods (/ – unknown vessel type, om – optical microscopy, xrpd – x-ray powder diffraction, icp-es – inductively coupled plasma-emission spectrometry, icp-ms – inductively coupled plasma-mass spectrometry). sample number vessel type period om xrpd icp-es, icp-ms st ar o či če -g ra di šć e 252 pot late mediaeval + 253 pot late mediaeval + + 254 pot late mediaeval + 255 pot late mediaeval + + 256 pot late mediaeval + + + 257 pot late mediaeval + 258 lid roman period + + 259 / roman period + + 260 / roman period + + 261 pot late bronze age + + 262 pot late bronze age + + 263 pot early bronze age + + 264 pot early bronze age + + 265 / early bronze age + + 266 / early bronze age + 267 / early bronze age + + 268 / early bronze age + 269 / copper/early bronze age + + 270 / copper/early bronze age + 271 bowl copper/early bronze age + + 272 / copper/early bronze age + 273 bowl copper age + 274 bowl copper age + + 275 / copper age + 276 / copper age + 277 / copper age + + 278 / copper age + + 279 / copper age + + 280 / copper age + + 281 / copper age + 282 / copper age + + 283 / neolithic + + 284 pot neolithic + + 285 pot neolithic + + + 286 / neolithic + + 287 / neolithic + 288 pot neolithic + + 289 pot neolithic + + 290 / neolithic + 291 / neolithic + + ku ril ov ec -b el in šč ic a 14130 bowl middle/late bronze age + 14131 pot middle/late bronze age + 14134 small jug middle/late bronze age + 14135 / middle/late bronze age + 14138 / middle/late bronze age + 14139 tripod pan middle/late bronze age + 14144 bowl middle/late bronze age + 14146 bowl middle/late bronze age + 14147 bowl middle/late bronze age + 14148 bowl middle/late bronze age + 14150 bowl middle/late bronze age + 14151 pot middle/late bronze age + 14152 pot middle/late bronze age + 14223 / early bronze age + g eologia c roatica 273neral et al.: tracing the origin of raw materials used for the production of ancient ceramics: a case study of multi-period archaeological sites ... difference between the original and dried volumes of each sample. a selection of 27 ceramic sherds (13 from staro čičegradišće and 14 from kurilovec-belinščica) and five clayey samples (two from staro čiče-gradišće and three collected near kurilovec-belinščica site) were subjected to inductively coupled plasmamass (icp-ms) and emission spectrometry (icp-es) in the bureau veritas minerals laboratory. the concentration of major oxides, together with minor elements, was determined by icp-es after lithium borate fusion, whereas the composition of trace and rare earth elements (ree) was determined after modified aqua regia digestion (1:1:1 hno3:hcl:h2o) by icp-ms. the detection limit for major oxides; sio2, al2o3, mgo, cao, na2o, k2o, tio2, p2o5 is 0.01 %, for cr2o3 the limit is 0.002 % and for fe2o3 is 0.04 %. detection limits for minor and trace elements are: v=8 ppm; ba, zr, nb=5 ppm; y=3 ppm; sr=2 ppm; sc, be, sn, zn=1 ppm; ga, sr, w, au, se=0.5 ppm; nd=0.3 ppm; co, figure 2. representative pottery from the staro čiče-gradišće and kurilovec-belinščica sites. more information about the ceramics is given in table 1. g eo lo gi a c ro at ic a 274 geologia croatica 77/3 figure 3. thin section photomicrographs of ceramics from the staro čiče-gradišće site. (a) fabric group 1, sample 291, (b) fabric group 2, sample 285, (c) fabric group 3, sample 279, (d) fabric group 4, sample 283, (e) fabric group 5, sample 286, (f) unclassified overfired sample 254, (g) lithoclast tempered ceramic sample 264, (h) calcite tempered sample 288, (i) mollusc shells tempered sample 274, (j) grog tempered sample 282. all photographs are taken in cross polarized light (xpl). g eologia c roatica 275neral et al.: tracing the origin of raw materials used for the production of ancient ceramics: a case study of multi-period archaeological sites ... th=0.2 ppm; cs, hf, rb, nb, ta, u, la, ce, mo, cu, pb, ni, cd, sb, ag, tl=0.1 ppm; gd, dy, yb=0.05 ppm; er=0.03 ppm; pr, eu, ho=0.02 ppm; tb, tm, lu, hg= 0.01 ppm. the results of geochemical analyses were subjected to biand multivariate statistical analysis in tibco statistica software 2020. all the elements with concentrations below the detection limit were excluded from the statistical analysis. 4. results 4.1. ceramic petrography the ceramic matrix is composed of naturally present, very fine (< 0.1 mm) and fine (0.1 – 0.25 mm) quartz, feldspar, and mica (muscovite and biotite) crystalloclast inclusions that are sparsely (< 10 %) to abundantly (40 %) present. these crystalloclasts are sub-angular and well to very well distributed in the matrix. by observing the amount and size of mineral inclusions in the clay matrix, five fabric groups have been determined (fig. 3, table 2). the matrix colour is brown to dark brown in ppl (plane polarized light) while the optical activity of the matrix, in xpl (cross polarized light), varies from low to high but it is mostly medium-high. two samples (254 and 257) remain unclassified regarding the highly vitrified clay matrix (fig. 3, table 2). along with naturally present crystalloclasts in the matrix, fragments of sedimentary, metamorphic, and igneous rocks (lithoclasts) are present in 18 samples (45 % of total samples, fig. 3g). sedimentary rocks are the most abundant within the first fabric group (1). these are mostly siltstones whereas limestone, dolomite and chert are less frequent. igneous rocks are present in most of the samples and are composed of feldspar, biotite and quartz indicating their acidic origin or quartz bearing intermediate rocks. among metamorphic rocks, quartzite is the most common, whereas schist is rarely present. most of these lithoclasts-tempered samples contain monoand polycrystalline quartz which sometimes contain cracks. lithoclasts are moderately to very commonly present (7 – 30 %), fine to very coarse (0.1 – > 3 mm) in size and mostly poorly to moderately sorted in the matrix. most of the samples contain both sub-angular and sub-rounded lithoclasts although the sedimentary inclusions are more rounded than the igneous and metamorphic clasts. very angular, fine to very coarse and poorly sorted calcite is recorded in one sample (288, fig. 3h). besides, nine samples (23 %) contain moderate to very common (10 – 30 %) amounts of elongated and slightly curved mollusc shell fragments (fig. 3i). grog (cheramoclasts) is determined in 12 samples (30 %, fig. 3j). the composition of grog is most often similar to the composition of the ceramic matrix whereas the main difference is in the colour and, sporadically, in the amount of very fine and/or fine crystalloclast inclusions. the amount, shape, and bimodal grain size distribution suggest that lithoclasts, calcite, grog, and mollusc shells were intentionally added inclusions (tempering material). therefore, by observing these intentionally added inclusions (tempering material), 14 fabric subgroups have been determined. clay pellets were recorded in negligible quantities. most of them are transparent with sharp and clear edges. the amount, size, and shape of the pores vary significantly among the samples. the pores are moderately present, 10 % on average, mostly elongated, parallel to the vessel walls, and sporadically filled with secondary calcite. rounded and irregular pores are less frequent. the mineral composition of the fired clay briquettes is very similar in all the samples, composed of angular and subangular monocrystalline quartz and feldspar inclusions (fig. 4, table 3). among the mica minerals, muscovite is the most common whereas biotite occurs less frequently. most of the samples contain sparse amounts (3 – 7 %) of fine and subfigure 4. thin section photomicrographs of fired clay briquettes; (a) sample 102, (b) sample 105, (c) sample 107 and (d) sample 108. g eo lo gi a c ro at ic a 276 geologia croatica 77/3 ta bl e 2. c er am ic p et ro gr ap hy a na ly si s o f p ot te ry th in s ec tio ns fr om th e st ar o či če -g ra di šć e si te (l – lo w , m h – m ed iu m -h ig h, h – h ig h; f – fi ne , m – m ed iu m , c – c oa rs e, v c – ve ry c oa rs e, p s – po or ly s or te d, m s – m ed iu m so rt ed , w s – w el l s or te d, v w s – ve ry w el l s or te d, s a – s ub -a ng ul ar , a – a ng ul ar , v a – v er y an gu la r, sr – s ub -r ou nd ed , + – p re se nt , + + – do m in an t, / – u na bl e to e st im at e th e am ou nt o f c ry st al lo cl as t i n th e m at rix s in ce th e sa m pl es a re o ve rfi re d. ra w c la y te m pe r m at er ia l sa m pl e nu m be r optical activity very fine crystalloclasts (%) fine crystalloclasts (%) quartz feldspar muscovite biotite temper amount (%) temper size temper sorting temper roundness metamorphic and igneous fragments sedimentary fragments calcite mollusc shells grog amount (%) grog size grog sorting grog roundness fabric subgroups 25 2 h <1 0 + + + + 30 f/ c m s sa /s r + + + 1. 1 25 3 m h + + + 25 f/ c m s sa /s r + + + 1. 1 25 5 m h + + + 30 vw s m s sa /s r + + + 1. 1 25 9 h + + 40 f/ m vw s sr + + + 1. 1 26 6 m h + + + 20 m /c ps sr + + + 1. 1 26 8 m h + + + 15 m /c m s sa /s r + + + 1. 1 27 8 h + + + 25 m c w s sa 1. 2 28 0 h + + + 7 m w s a + + 15 m c m s sa 1. 3 28 1 h + + + + 30 f/ vc ps a + + 10 m c w s sa 1. 3 28 9 h + + + 30 m /c m s sa /s r + + + 1. 1 29 0 h + + + + 40 f/ c ps sa + 1. 1 29 1 h + + + + 30 f/ c ps sa /s r + 1. 1 25 6 m h 15 – 2 5 3 – 10 + + + 25 m /c ps sa /s r + + + + 2. 1 26 4 m h + + + 20 m /v c ps sr + + 2. 2 27 3 h + + + 30 f/ c w s a + 2. 3 27 4 m h + + + 30 f/ c w s a + 2. 3 27 5 m h + + + 20 f/ c m s a + 2. 3 27 6 m h + + + + 10 f/ m w s a + 15 m /c m s sa 2. 4 27 7 m h + + + + 20 f/ c ps a + 2. 3 28 2 m h + + + 15 f/ m w s a + 30 f/ c m s sa 2. 4 28 5 m h + + + 2. 5 28 8 m h + + 25 f/ vc ps va + + 2. 6 26 1 h 20 – 3 0 10 – 1 5 + + + + 30 m /v c ps sa 3. 1 26 2 m h + + + + 40 m /v c ps sa 3. 1 26 3 m h + + + 20 m /v c ps sa + + + 3. 2 26 5 m h + + + + 15 m /c m s sa + + + 3. 2 26 7 h + + + 25 f/ c m s sa /s r + + 3. 2 26 9 m h + + + 25 m w s sa 3. 1 27 0 m h + + + 20 m w s sa 3. 1 27 1 m h + + + 15 m w s sa 3. 1 27 2 m h + + + 25 m /c w s sa 3. 1 27 9 h + + + 30 f/ c ps a + 3. 2 25 8 m h 40 3 – 10 + + + + 15 f/ m w s sa /s r + + + 4. 1 26 0 l + + + 4. 2 28 3 h + + + + 4. 2 28 4 m h + + + + 4. 2 28 7 m h + + + 4. 1 28 6 h 40 15 + + + 5. 1 25 4 l / / + + + 25 m /c w s sa + + / 25 7 l + + + + 25 f/ c m s sa /s r + + + / g eologia c roatica 277neral et al.: tracing the origin of raw materials used for the production of ancient ceramics: a case study of multi-period archaeological sites ... angular to sub-rounded metamorphic (quartzite, schist) and igneous rocks. sedimentary fragments are siltstones and less commonly dolomites, fine-grained in size and mostly subrounded. larger quartz grains have cracks as a result of the firing process. according to the high amount of the crystalloclasts in the matrix, all of the samples are determined as sandy clay. however, three samples (100, 106 and 107, fig. 4) can be discriminated from others regarding their significantly high amount of fine and medium quartz and feldspar inclusions. 4.2. mineralogy quartz, k-feldspar and plagioclase are the major components in almost all of the ceramic samples, partly as a result of the igneous and metamorphic inclusions present in the samples (table 4). the abundance of calcite discriminates samples 274 and 288 from all others. in sample 274, it suggests the thermal decomposition from aragonite in mollusc shells fragments (shell-tempered ceramics) whereas in sample 288 it reflects the common presence of calcite inclusions determined by optical microscopy. calcite is commonly associated with the traces of dolomite. spinel, haematite and anatase/rutile are rarely present in the samples. the diffraction maxima at 10 å, corresponding to mica and a dehydroxylated illite-like phase is determined in all the samples. the traces of 14 å phyllosilicates are sporadically recorded (samples 267, 274 and 282). the mineralogical composition of the clayey samples (table 4) consists mostly of quartz, k-feldspar, plagioclase and mica, including mica-illite and illite/smectite. carbonates, including calcite and dolomite, are characteristic of all the samples but the amount of dolomite generally exceeds that of calcite. the traces of ferrous minerals (haematite, goethite and/ or pyrite) are present in most of the samples whereas amphibole is only recorded in sample 105. the treatments conducted on the < 2 μm fraction revealed differences in the clay mineral compositions. samples 102, 103, 104 and 108 (fig. 5) are table 3. petrographic analysis of clayey sediments collected in the vicinity of the staro čiče-gradišće archaeological site (mh – medium-high; + – present). sample number optical activity very fine crystalloclasts (%) fine crystalloclasts (%) quartz feldspar muscovite biotite metamorphic and igneous fragments sedimentary fragments mollusc shells 99 mh 50 2 + + + + 100 mh 15 25 + + + + + + 102 mh 30 10 + + + + + + 103 mh 30 10 + + + + 104 mh 25 15 + + + + 105 mh 40 3 + + + + + 106 mh 20 20 + + + + + + 107 mh 15 30 + + + + + + 108 mh 25 15 + + + + figure 5. x-ray powder diffraction patterns of clayey sample 108. g eo lo gi a c ro at ic a 278 geologia croatica 77/3 discriminated from others regarding the high swelling clay mineral content, preferably vermiculite, which corresponds to the highest amount of the clay fraction determined by laser granulometry. the highest content of swelling clays is determined in sample 108. conversely, the other samples are characterized by kaolinite and chlorite with the trace presence of swelling clays. mixed-layer clay minerals are less frequently present. the dominance of the 10 å phyllosilicates (mica) and clay minerals (illite) together with the traces of 7 and 14 å clay minerals is in line with “no plasticity” of the sample 101 observed on site. 4.3. plasticity and grain size analysis test rollers were modelled from the clayey samples in order to estimate the shrinkage. two samples (101 and 107) were inappropriate for modelling a test roller due to their low plasticity and/or higher sand fraction. the results do not show the clear correlation between the plasticity range, grain size distribution and/or the shrinkage value (table 5) as it is affected by several factors including the type of clay minerals, chemical composition, crystallinity, ph, impurities etc. rather than just the particle size or shape (guggenheim & table 4. semiquantitative mineralogical composition of ceramics from the staro čiče-gradišće site and clayey material collected near the site determined by x-ray powder diffraction (qtz – quartz, pl plagioclase, kfs – k-feldspar, mca – micaceous material; including mica, illite and illite/smectite, cal – calcite, dol – dolomite, amph – amphibole, hem – hematite, gt – goethite, sp – spinel, ant – anatase, rt – rutile, kaol – kaolinite, chl – chlorite, sm – smectite, vm – vermiculite – not detected, * – traces, + – minor, ++ – intermediate, +++ – major). sample number qtz pl kfs mca cal dol amph hem/gt sp ant/rt kaol chl sm, vm ce ra m ic s 255 + + +++ + + * 256 ++ + + + + * 259 + + + ++ + * 260 + + ++ + * 262 + + + + * 263 + ++ + + + 267 ++ + + + * * * * 269 ++ + + * * 274 * + + +++ * * * 279 + + + + * 282 + + + + * * 283 ++ + + + 285 + + + ++ + 288 + + + +++ 289 ++ + + + * 291 + + ++ + * cl ay ey m at er ia l 99 ++ + + ++ + + * + + * 100 ++ + + ++ + + * + + * 101 ++ + + ++ + + * * * 102 ++ + + ++ * * + + ++ 103 ++ + * ++ * * + + ++ 104 ++ + + ++ * * * + + ++ 105 ++ + + ++ * + * + + * 106 ++ + + ++ + + + + * 107 +++ + + ++ * + ++ ++ * 108 ++ + + ++ * + + + ++ table 5. list of clayey samples from the staro čiče-gradišće site with sampling depth, plasticity, munsell colour and shrinkage values (/ not measured). sample number sampling depth (cm) plasticity munsell color shrinkage (%) 99 100 moderate 10 yr 3/1 very dark grey 35 100 120 moderate 10 yr 3/1 very dark grey 32 101 115 no plasticity 5y 4/2 olive grey / 102 50 moderate 10 yr 4/2 dark greyish brown 33 103 60 low 10 yr 4/2 dark greyish brown 28 104 30 moderate 2.5y 4/2 dark greyish brown 19 105 80 high 2.5y 3/2 very dark greyish brown 49 106 140 moderate 2.5y 3/1 very dark greyish brown 32 107 90 low 2.5y 3/1 very dark greyish brown / 108 50 high 2.5y 5/3 light olive brown 28 g eologia c roatica 279neral et al.: tracing the origin of raw materials used for the production of ancient ceramics: a case study of multi-period archaeological sites ... martin, 1995; semiz, 2017; moreno-maroto & alonso-azcárate, 2018). according to the grain size distribution of the clayey samples collected in the vicinity of the staro čiče-gradišće site, more than 90 vol. % of the particles in all of the samples are in a range between 4 and 113 µm. the majority of samples have more than 20 vol. % of sandy fraction (22 % – 42.50 vol. %) and less than 10 vol. % of clay. the remaining samples are characterized by their lower sand content (2 – 17.50 vol. %) and slightly greater amounts of clay (19 – 30 vol. %). all of the samples have the highest proportion of silt (52 – 72 vol. %) and can be therefore determined as sandy or clayey silt. however, the non-spherical shape of the clay particles combined with measurement limits, led to a different evaluation increasing the silt fraction (fedotov et al., 2007; polakowski et al., 2014; mako et al., 2017). taking that into account, all of the samples may be assigned as sandy or silty clay as confirmed by the optical microscopy. 4.4. geochemical analysis the major, minor, and rare earth element (ree) contents were measured to identify the element concentration patterns among both the ceramics (27 samples) and clayey material (five samples, suppl. 1). major oxide concentrations revealed some variations among the clayey and the ceramic samples (suppl. 1). the low cao content in the clayey material collected near the kurilovec-belinščica site (< 1 %) distinguishes the samples from those collected near staro čiče-gradišće which are characterized by higher cao values (up to 7.6 %) (fig. 6a, b). these clayey samples, related to the staro čiče-gradišće, are further distinguished from others according to their higher mgo (around 3 %) content which may reflect dolomite in the samples. the concentrations of other major oxides are generally uniform among the clayey samples. the abundance of sio2 (~59.65 %) may be related to the high quartz, feldspar, and illite/muscovite content (fig. 6a). the ceramic sherds from staro čiče-gradišće are discriminated from those found at the kurilovec-belinščica site by their higher cao (~5.68 %) content. the abundance of cao is commonly followed by the higher sr, a typical isomorphic element in ca-bearing minerals (gonzález et al., 2018; gutsuz et al., 2017). the very high concentration of cao and loss on ignition (loi) in sample 277 (suppl. 1) is the result of shell-tempered ceramics whereas the amount of sio2 in the ceramics is likely controlled by different types of igneous and metamorphic rocks added as a temper. therefore, the lower sio2 is in general recorded in the samples without or with a lesser amount of lithoclast temper (samples 265, 277, 278, 280 and 285). the p2o5 content is below 5 % except for sample 14147. this probably ref lects post-depositional figure 6. bivariate plots of (a) sio2 vs cao, (b) fe2o3 vs cao, (c) sr vs rb, (d) lree (la, ce, pr, nd, sm, eu) vs hree (gd, tb, dy, ho, er, tm, yb, lu), (e) projection of the variables on the factor-plane and (f) principal component analysis based on ree conducted on ceramics from the staro čiče-gradišće and kurilovec-belinščica site and on clayey samples. g eo lo gi a c ro at ic a 280 geologia croatica 77/3 alterations (freestone et al., 1994; from santos rodrigues et al., 2015) although some authors relate the phosphorus level primarily to the use of pots for cooking (costa et al., 2011). the samples from staro čiče-gradišće are slightly enriched in sr if compared with ceramics from the kurilovec-belinščica site (fig. 6c). although the concentration of the major and minor elements is commonly affected by tempers that potters add to the raw clay, the rare earth elements tend to be allocated to the reactive surface of the clay minerals (carloni et al., 2021 and references therein) which makes them suitable for investigating the provenience of the clayey raw materials. moreover, their concentration patterns do not significantly alter after the firing process (gutsuz et al., 2017). all of the samples have lree > hree. a diagram showing the total amount of light ree (la-eu) and heavy ree (gd-lu) exposed two separate groups that generally correspond to different archaeological sites; the ree-poor sherds from the staro čiče-gradišće site and ree-rich sherds from kurilovecbelinščica site (fig. 6d). the clayey samples collected near staro čiče-gradišće have similar ree composition to the ceramic sherds from the staro čiče-gradišće site whereas those collected near kurilovec-belinščica site corresponds to the sherds from kurilovec-belinščica site. principal component analysis based on ree concentrations shows samples’ distribution mainly according to the ce, la and nd concentrations (fig. 6e). a scatter plot of the component scores revealed a single cloud but with samples from staro čičegradišće having higher factor 1 values if compared with the ceramics from kurilovec-belinščica. two neolithic samples (285 and 286) represent outliers (fig. 6f). 5. discussion 5.1. clayey raw material investigations of pottery practices have shown that the process of procuring clayey material is mainly reduced to the minimal expenditure of time and a minimal distance from the place of production (arnold, 1985, 2005; gosselain & livingstone smith, 2005). according to ethnographic examples, the clayey materials can be extracted using four main methods (surface, pit, gallery, and underwater extraction) depending on the characteristics of the surrounding area. therefore, following the alluvial characteristics of the turopolje region it is assumed that the raw clays used for pottery production was procured in a nearby environment including floodplains, fields, marshes, riverbeds, etc., mainly as surface or underwater extraction (gosselain & livingstone smith, 2005). this is confirmed by the results of this study, which point to the local origin of the raw materials. comparison of the geochemical patterns of ceramics with the clayey samples shows that the ceramics from the kurilovec-belinščica site are most similar to the clayey samples collected in the brickyard located 3 km from the site. similarly, the ceramics from the staro čiče-gradišće correspond well with the clayey samples collected up to 0.5 km from the site. the collected clays are flood deposits with similar mineralogical composition and are characterized by moderate or high plasticity, which initially makes them suitable for pottery making. additionally, alluvial characteristics of the area suggest the collected samples are secondary clays transported from the parent rock (velde & meunier, 2008). apart from the clayey samples, ceramic sherds are characterized by similar mineralogical composition observed by xrpd analysis. however, optical microscopy of thin sections indicated differences in the size and amount of crystalloclasts in the matrix resulting in five determined fabric groups: from inclusion-poor, very plastic clay to the inclusionrich, moderately plastic clay. the variability of these inclusions is not necessarily associated with different source locations but may indicate different depths of the raw clay exploitation. namely, deposition of the larger mineral grains, mostly of quartz and feldspar, causes their enrichment with increasing depth. inclusion-poor clays are more common in the surface sediments and are characterized by greater amounts of the swelling clay minerals which is confirmed by both the mineralogical and grain size analyses. however, research has shown that particular communities from the past preferred one type of raw material over another. some patterns, concerning the proportion of sandy and inclusion-poor clay, can be observed by comparing thinsections of pottery from the staro čiče-gradišće but also those of the bronze age ceramics from kurilovec-belinščica site (kudelić & sirovica, 2022). the comparison shows that the most common type of clayey material during almost all the past periods is sandy clay with 15 – 30 % of very fine crystalloclast inclusions in the matrix. inclusion-poor or fat clays (less than 10 % of crystalloclasts) were less common but very frequently used during the bronze age. very sandy clay (more than 40 % of crystalloclasts) was sporadically present in the bronze age but more commonly used by potters during the neolithic and the late antiquity periods. therefore, based on the findings of this research, it is concluded that communities throughout all periods of the past exploited clayey materials from the vicinity of the settlement, as confirmed by the characteristics of the samples collected in the immediate environment. 5.2. temper material the study of raw materials used in the past is challenging because potters usually modify the original raw material in order to change its properties and adapt it to their needs. therefore, during analysis, it is important to distinguish the original from the added or modified material. pottery mixtures usually consist of two elements: raw clay as the basic element and temper that potters add to the clay (crushed rocks, minerals, ceramics or plant materials). the significance of temper material is manifested through its techno-functional role. they improve the viscosity of the clay paste, the strength of the vessel and the resistance to thermal stress (rice, 1987; velde & druc, 1999) or directly affect the properties of the final product (albero santacreu, 2014). the results showed that potters used different temper materials the choice of which is mostly very characteristic for a particular period of the past, i.e. for particular communities. the most common temper material are lithoclasts: sub-angular to sub-rounded fragments of various sedimentary, igneous and metamorphic rocks. these are used by the communities from g eologia c roatica 281neral et al.: tracing the origin of raw materials used for the production of ancient ceramics: a case study of multi-period archaeological sites ... the neolithic, early bronze age, late antiquity and late mediaeval periods (fig. 7a). the variability of the lithoclasts and the sub-rounded shape indicate that these materials are sand and gravel transported from rivers and smaller watercourses, probably from riverbed gravel bars at the bank of the nearby river. according to the investigation of the provenance of pebbles from the sava river (a nearby gravel pit located around 1 km from the staro čiče-gradišće site), carbonates are dominant with a smaller proportion of igneous rocks (barudžija et al., 2020). the pebble characteristics correspond to the rock temper present in ancient ceramics, particularly those from the late antiquity and late mediaeval periods. locally available temper material can also be assumed for the copper age community using crushed mollusc shells that were probably exploited from the nearby rivers and watercourses. such a choice of raw materials and such abundantly used temper have not been previously recorded in a wider area of research, representing the valuable evidence of specific technological praxis present among the community from the copper age. late copper/early bronze age together with late bronze age potters made exclusively grog-tempered pottery (kudelić et al., 2018; kudelić & sirovica, 2022; neral et al., 2023). however, four samples contain grog in addition to shell temper. although the local origin (of both clays and tempers) is confirmed for most of the ceramics, the sole exceptions are the neolithic samples. namely, a diverse geochemical pattern of two samples suggests a different source of clayey material. additionally, the third sample is calcite tempered. calcite is not of local origin considering the geological framework of the area (cgs, 2009), although its presence corresponds well with the ceramics from the eastern adriatic coast, i.e. karst environment (žibrat gašparič, 2004; dolenec et al., 2012; spataro, 2002; kudelić et al., 2023). this strongly suggests either exploiting resources from more distant locations or that exchange networks were present among the neolithic communities. according to previous studies and considerations (kreiter, 2007; albero santacreu, 2014), the choice of pottery raw materials, especially temper, can be culturally conditioned, which partly rejects environmental and technofunctional reasons. this research has shown that the choice of raw materials was certainly conditioned by resource’ availability in the immediate environment. however, despite the easily available and moderately plastic sandy clay, bronze age communities from turopolje also commonly exploited specific sources of the inclusion-poor, highly plastic clay. this kind of clayey material has a higher proportion of the swelling clay minerals that cause significant volume change that can negatively affect the final product. in order to achieve optimal plasticity and reduce the overall volume change these clays are most commonly tempered with non-plastic materials (velde, 1992) which has also been supported by this research (fig. 7b). however, according to the research results of pottery raw materials of bronze age communities from continental croatia, preference is given to sandy clay (neral et al., 2023). therefore, it can be assumed that the choice of inclusionpoor clay is of local significance. 6. conclusion this research presents the analyses of ancient ceramics from the multi-period archaeological sites in continental croatia and potential clayey raw materials collected in the immediate environment and experimental clayey briquettes made from the collected clay. the study employed a multi-analytical approach to examine paste recipes, characterise raw materials, and explore their provenance, availability, and spatial distribution. several key conclusions emerged from this investigation: – ancient potters preferred to use the moderately plastic, sandy clay, while highly plastic clay is frequently exploited only by the bronze age potters – the potters used various tempering materials related to particular social groups and/or different periods of the past – the most commonly used tempers, characteristic of the neolithic, the early bronze age, the late antiquity, and figure 7. (a) the proportion of different types of tempering material in ceramics from the staro čiče-gradišće site in relation to different periods of the past. (b) the proportion of different types of tempering material in ceramics from the staro čiče-gradišće and kurilovec-belinščica site in relation to different types of the clayey raw material. g eo lo gi a c ro at ic a 282 geologia croatica 77/3 the late mediaeval period are sands and gravels exploited from the nearby rivers. grog is characteristic only of the bronze age. copper age potters extensively used mollusc shells as a temper, which strongly indicates a specific technological praxis present among this community – most of the ceramics are of local origin, made from readily available raw materials present in the landscape composed of flood sediments of the nearby sava river – the only non-local raw materials were detected in the neolithic samples, as evidenced by the use of non-local calcite temper and their different geochemical composition. the study demonstrates that the investigated area possesses clay suitable for pottery production, thereby supporting the prevalent use of local sources. however, a more pronounced variety was recorded in the selection of tempering material, conditioned by the improvement of technological features but also by the regional pottery traditions specific to certain communities of the past. acknowledgement this research has been supported by the croatian science foundation under the project prepot – technological features and cultural practices in prehistoric pottery traditions in croatia (uip-2020-02-3637) and partly by the ministry of science and education of republic of croatia under the project dinaric karst: geological evolution, mineral resources, palaeosols and soils (195-1953068-2704). it was also created within the project synergy of diversity: archaeology of landscape and technological traditions in continental and adriatic croatia (1802, sirakt) funded by the european union-nextgenerationeu. references albero santacreu, d. (2014): materiality, techniques and society in pottery production: the technological study of archaeological ceramics through paste analysis. warsaw, poland: de gruyter open poland. https://doi.org/10.2478/9783110410204 amicone, s., freund, k., mancini, p., d'oriano, r. & berthold, c. (2020): new insights into early iron age connections between sardinia and etruria: archaeometric analyses of ceramics from tavolara.-journal of archaeological science: reports, 33, 102452. 10.1016/j.jasrep.2020.102452. andaloro, e., belfiore, c., francesco, a., jacobsen, j. & mittica, g. (2011): a preliminary archaeometric study of pottery remains from the archaeological site of timpone della motta, in the sibaritide area (calabria southern italy).-applied clay science, 53(3), 445–453. 10.1016/j.clay.2010.07.021. arnold, d.e. (1985): ceramic theory and cultural process, new studies in archaeology. cambridge university press, cambridge. arnold, d.e. (2005): linking society with the compositional analyses of pottery: a model from comparative ethnography. in: livingstone smith, a., bosquet, d. & martineau r. (eds.): pottery manufacturing processes: reconstitution and interpretation. bar international series 1349, archeopress, oxford, pp. 15–21 balen-letunić, d. (1996): new late bronze age sites from the zagreb area.– in: čečuk, b. (eds.): archaeological research in zagreb and the zagreb region and archaeology and reconstruction [novi kasnobrončanodobni lokaliteti sa zagrebačkog područja. u: čečuk, b. (ur.): arheološka istraživanja u zagrebu i zagrebačkoj regiji i arheologija i obnova – in croatian]. – izdanja hrvatskog arheološkog društva 17, hrvatsko arheološko društvo, zagreb, 13–27. barudžija, u., velić, j., malvić, t., trenc, n. & matovinović božinović, n. (2020): morphometric characteristics, shapes and provenance of holocene pebbles from the sava river gravels (zagreb, croatia).geoscience, 10(92), 1–20. https://doi.org/10.3390/geosciences10030092 basch, o. (1981): osnovna geološka karta sfrj 1:100.000, list ivanić-grad l33–81 [basic geological map of sfry 1:100000, ivanić-grad sheet – in croatian]. – geološki zavod, zagreb, savezni geološki institut, beograd. basch, o. (1983): osnovna geološka karta sfrj 1:100.000, tumač za list ivanić-grad l33–81 [basic geological map of sfry 1:100000, geology of the ivanić-grad sheet – in croatian].– geološki zavod, zagreb, savezni geološki institut, beograd, 66 p. belfiore, c., la russa, m., barca, d., galli, g., pezzino, a., ruffolo, s., viccaro, m. & fichera, g. (2014): a trace element study for the provenance attribution of ceramic artefacts: the case of dressel 1 amphorae from a late-republican ship.– journal of archaeological science, 43, 91–104. doi: 10.1016/j.jas.2013.12.015 beltrame, m., sitzia, f., arruda, a., barrulas, p., barata, f. & mirao, j. (2021): the islamic ceramic of the santarém alcaçova: raw materials, technology, and trade.– archaeometry, 63. doi: 10.1111/ arcm.12671 carloni, d., šegvić, b., sartori, m., zanoni, g., moscariello, a. & besse, m. (2021): raw material choices and material characterization of the 3rd and 2nd millennium bc pottery from the petit‐chasseur necropolis: insights into the megalith‐erecting society of the upper rhône valley, switzerland.– geoarchaeology, 36/6, 1009–1044. doi: 10.1002/gea.21867 croatian geological survey (2009): geological map of republic of croatia, m 1:300.000. croatian geological survey, zagreb. costa, m.l., rios, g.m., silva, m.m.c., silva, g.j. & valdes, u.m. (2011): mineralogy and chemistry of archaeological ceramic fragments from archaeological dark earth site in colombian amazon.– rev. esc. minas, 64/1, 17–23. doi: 10.1590/s0370-44672011000100002 crnković, b. & bušić, m. (1970): mineraloško-petrografski sastav nanosa rijeke save [mineralogical-petrographic composition of sava river deposits – in croatian].– in: zbornik radova rgn fakulteta sveučilišta u zagrebu u povodu 30 g. rada (1939–1969), 133–140. dolenec (kramar), s., lux, j., mladenovic, a., pristacz, h., mirtič, b., sagadin, m., rogan šmuc, n. (2012): mineralogical and geochemical characteristics of roman pottery from an archaeological site near mošnje (slovenia).– applied clay science, 57, 39–48. doi: 10.1016/j.clay.2011.12.008 durman, a. (1983): "gradišće" u starom čiču – brončanodobni tel ["gradišće" in staro čiče – bronze age tell – in croatian].– obavijesti hrvatskog arheološkog društva, 15/2, 26–27. fedotov, g.n., shein, e.v., putlynev, v.i., arkhangel’skaya, t.a., eliseev, a.v. & milanovskii, e.y. (2007): physicochemical bases of differences between the sedimentometric and laser diffraction techniques of soil particle-size analysis.– eurasian soil science, 40, 281– 288. doi: 10.1134/s1064229307030064 freestone, i., middleton, a. & meeks, n. (1994): significance of phosphate in ceramic bodies: discussion of paper by bollong et al.– journal of archaeological science, 21, 425–426. gonzález, i., romero-baena, a., galán, e., miras, a., castilla alcántara, j.c. & campos, p. (2018): ceramic materials from cuatrovitas archaelogical site (spain): a mineralogical and chemical study for determining the provenance and the firing temperature.– applied clay science, 166, 38–48. doi: 10.1016/j.clay.2018.09.003 gosselain, o.a. & livingston smith, a. (2005): the source: clay selection and processing practices in sub-saharan africa.– in: livingstone smith, a. bosquet, d. & martineau, r. (eds.): pottery manufacturing processes: reconstruction and interpretation. bar international series 1349, archaeopress, oxford, pp. 33–47. g eologia c roatica 283neral et al.: tracing the origin of raw materials used for the production of ancient ceramics: a case study of multi-period archaeological sites ... guggenheim, s. & martin, r.t. (1995): definition of clay and clay mineral: joint report of the aipea nomenclature and cms nomenclature committees.– clay and clay minerals, 43/2, 255–256. doi: 10.1346/ccmn.1995.0430213 gutsuz, p., kibaroğlu, m., sunal, g. & haciosmanoğlu, s. (2017): geochemical characterization of clay deposits in the amuq valley (southern turkey) and the implications for archaeometric study of ancient ceramics.– applied clay science, 141, 316–333. doi: 10.1016/j. clay.2017.03.004 ionescu, c., hoeck, v. & ghergari, l. (2011): electron microprobe analysis of ancient ceramics: a case study from romania.– applied clay science, 53/3, 466–475. doi: 10.1016/j.clay.2010.09.009 iordanidis, a., garcia-guinea, j. & karamitrou-mentessidi, g. (2009): analytical study of ancient pottery from the archaeological site of aiani, northern greece.– materials characterization, 60, 292– 302. doi: 10.1016/j.matchar.2008.08.001 kałaska, m., druc, i., chyla, j., nita, r., syczewski, m., siuda, r., makowski, k. & giersz, m. (2020): application of electron microprobe analysis to identify the origin of ancient pottery production from the castillo de huarmey, peru.– archaeometry, 62/6, 1095– 1114. doi: 10.1111/arcm.12581 kreiter, a. (2007): technological choices and material meanings in early and middle bronze age hungary: understanding the active role of material culture through ceramic analysis.– bar international series 1604, oxford. kudelić, a. (2016): kurilovec – belinščica – brončanodobno naselje u turopolju [kurilovec – belinščica – a bronze age settlement in the turopolje region – in croatian].– prilozi instituta za arheologiju 33, 5–52. kudelić, a. & sirovica, f. (2022): kurilovec – belinščica: tragom brončanodobnog turopolja / kurilovec – belinščica: tracing the bronze age of turopolje.– in: monographiae instituti archaeologici ix, institute of archaeology, zagreb. kudelić, a., mileusnić, m., grzunov, a., ottner, f. & wriesnig, k. (2018): archaeometry and comparative analysis of the bronze age pottery from turopolje and podravina region.– opvscula archaeologica, 39, 37–52. kudelić, a., neral, n. & paraman, l. (2023): archaeometry of bronze age ceramics from the area of trogir.– vjesnik arheološkog muzeja u zagrebu, 56/2. doi: 10.52064/vamz.56.2.1 kurečić, t. (2017): sedimentologija i paleoekologija pliocenskih viviparus slojeva vukomeričkih gorica [sedimentology and paleoecology of pliocene viviparus beds from the area of vukomeričke gorice – in croatian].– doctoral thesis, university of zagreb, faculty of science, pp. 153. mako, a., tóth, g., weynants, m., rajkai, k., hermann, t. & tóth, b. (2017): pedotransfer functions for converting laser diffraction particle-size data to conventional values.– european journal of soil science, 68, 769–782. doi: 10.1111/ejss.12456 mange, m. & bezeczky, t. (2006): petrography and provenance of laecanius amphorae from istria, northern adriatic region, croatia.– geoarchaeology, 21, 429–460. doi: 10.1002/gea.20115 maritan, l., mazzoli, c., nodari, l. & russo, u. (2005): second iron age grey pottery from este (northeastern italy): study of provenance and technology.– applied clay science, 29. 31–44. doi: 10.1016/j. clay.2004.09.003 maritan, l., mazzoli, c. & mazzocchin, s. (2019): provenance of wine and oil amphorae in northern adriatic: archaeometric and epigraphic approaches.– archéosciences, 203–210. doi: 10.4000/archeosciences.6732 maritan, l., gravagna, e., cavazzini, g., zerboni, a., mazzoli, c., grifa, c., mercurio, m., mohamed, a., usai, d. & salvatori, s. (2021): nile river clayey materials in sudan: chemical and isotope analysis as reference data for ancient pottery provenance studies.– quaternary international, 657/1. doi: 10.1016/j.quaint.2021.05.009 michelaki, k., braun, g.v. & hancock, r.g.v. (2014): local clay sources as histories of human–landscape interactions: a ceramic taskscape perspective.– journal of archaeological method and theory, 22, 783–827. doi: 10.1007/s10816-014-9204-0 miše, m. & quinn, p. s. (2022): origins and distribution of hellenistic and late republican transport amphorae in the dalmatian region and its implications for adriatic trade and economy.– archaeological and anthropological sciences, 14, 225. doi: 10.1007/s12520-022-01689-x miše, m., serneels, v., matana, a., montanari, a. & kirigin, b. (2019): provenance studies of amphorae from the greek colony pharos on the island of hvar, croatia.– in: koeberl, c. & bice, d.m. (eds.): 250 million years of earth history in central italy celebrating 25 years of the geological observatory of coldigioco. geological society of america special paper, 542 p., 471–499. doi: 10.1130/2019.2542(27) miše, m., quinn, p., charlton, m., serneels, v. & montanari, a. (2020): production and circulation of late hellenistic fine table ware in central dalmatia, croatia.– journal of archaeological science: reports, 33, 102537. doi: 10.1016/j.jasrep.2020.102537 moore, d.m. & reynolds, r.c. (1997): x-ray diffraction and the identification and analysis of clay minerals. second edition.– oxford university press, new york. moreno-maroto, j.m. & alonso-azcárate, j. (2018): what is clay? a new definition of “clay” based on plasticity and its impact on the most widespread soil classification systems.– applied clay science, 161, 57–63. doi: 10.1016/j.clay.2018.04.011 neral, n., kudelić, a., maričić, a. & mileusnić, m. (2023): pottery technology through time: archaeometry of pottery and clayey raw material from the multi-period site in eastern croatia.– the mining geology-petroleum engineering bulletin, 38/2, 1–21. doi: 10.17794/ rgn.2023.2.1 papachristodoulou, c., gravani, k., oikonomou, a. & ioannides, k. (2010): on the provenance and manufacture of red-slipped fine ware from ancient cassope (nw greece): evidence by x-ray analytical methods.– journal of archaeological science, 37, 2146–2154. doi: 10.1016/j.jas.2010.02.013 pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.– basin research, 13, 359–376. pcrg – prehistoric ceramic research group (2010): the study of later prehistoric pottery: general policies and guidelines for analysis and publication. prehistoric ceramic research group: occasional papers, nos 1 and 2, 3rd edition revised 2010. pikija, m. (1987a): osnovna geološka karta sfrj 1:100.000, tumač za list sisak l33–93 [basic geological map of sfry, 1:100000, geology of the sisak sheet – in croatian]. – geološki zavod, zagreb, savezni geološki institut, beograd, 55 p. pikija, m. (1987b): osnovna geološka karta sfrj 1:100.000, list sisak l33– 93 [basic geological map of sfry, 1:100000, sisak sheet – in croatian].– geološki zavod, zagreb, savezni geološki institut, beograd. polakowski, c., sochan, a., bieganowski, a., ryżak, m., földényi, r. & tóth, j. (2014): influence of the sand particle shape on particle size distribution measured by laser diffraction method.international agrophysics. 28, 195–200. quinn, p.s. (2013): ceramic petrography – the interpretation of archaeological pottery and related artefacts in thin section. archaeopress publishing ltd, oxford. ratto, n., gogni, v., bonoli escobar, m. & plá, r. (2015): mudclay banks and regional geochemistry: the provenance of ceramic raw materials (department tinogasta, catamarca, argentina).quaternary international, 375, 13–26. https://doi.org/10.1016/j.quaint.2014.07.018. rice, p.m. (1987): pottery analysis: a source book. the university of chicago press, chicago & london. rögl, f. & steininger, f.f. (1984): neogene paratethys, mediterranean and indopacific seaways. in: brenchley, p. (eds.), fossils and climate. john wiley & sons, new york, pp. 171–200. santos rodrigues, s.f., da costa, m.l., pöllmann, h., kern, d.c., imazio da silveira, m. & kipnis, r. (2015): pre-historic production of ceramics in the amazon: provenience, raw materials, and https://doi.org/10.1111/ejss.12456 g eo lo gi a c ro at ic a 284 geologia croatica 77/3 firing temperatures.applied clay science, 107, 145–155. https://doi. org/10.1016/j.clay.2015.01.016. semiz, b. (2017): characteristics of clay-rich raw materials for ceramic applications in denizli region (western anatolia).applied clay science, 137, 83–93. https://doi.org/10.1016/j.clay.2016.12.014 sillar, b. & tite, m.s. (2000): the challenge of technological choices for materials science approaches in archaeology.archaeometry, 42(1), 2–20. https://doi.org/10.1111/j.1475-4754.2000.tb00863.x snyder, r.l. (1992): the use of reference intensity ratios in x-ray quantitative analysis. powder diffraction, 7(4), 186–193. spataro, m. (2002): the first farming communities of the adriatic: pottery production and circulation in the early and middle neolithic. società per la preistoria e protostoria della regione friuli-venezia giulia, quaderno 9, edizioni svevo trieste. spataro, m. (2011): a comparison of chemical and petrographic analyses of neolithic pottery from south-eastern europe.journal of archaeological science, 38, 255–269. 10.1016/j.jas.2010.08.026. sterba, j., shinoto, m., shinzato, a., enomoto, m. & yomine, y. (2020): provenancing of pottery from kamuiyaki site in east asia by neutron activation analysis.archaeometry, 63 (5). 10.1111/arcm.12627. šarić, k., bikić, v. & erić, s. (2018): microstructural, mineralogical and petrographical characteristics of the medieval ceramics from the studenica monastery (unesco world heritage site): implications on the pottery technology and provenance of the raw material.microscopy and microanalysis, 24(6), 744–761, https://doi.org/10.1017/ s1431927618015349 šegvić, b., šešelj, l., slovenec, d., lugović, b., & mahlmann, r. f. (2012): composition, technology of manufacture, and circulation of hellenistic pottery from the eastern adriatic: a case study of three archaeological sites along the dalmatian coast, croatia.geoarchaeology, 27, 63–87. doi:10.1002/gea.21379 šikić, k., basch, o. & šimunić, a. (1978): osnovna geološka karta sfrj 1:100.000, list zagreb l33–80 [basic geological map of sfry, 1:100000, zagreb sheet – in croatian].– institut za geološka istraživanja, zagreb, savezni geološki institut, beograd. šikić, k., basch, o. & šimunić, a. (1979): osnovna geološka karta sfrj 1:100.000, tumač za list zagreb l33–80 [basic geological map of sfry, 1:100000, geology of the zagreb sheet – in croatian].– institut za geološka istraživanja, zagreb, savezni geološki institut, beograd, 81 p. šimunić, a. & basch, o. (1975): stratigraphy of the quaternary sediments of the zagreb posavlje area [stratigrafija kvartarnih sedimenata zagrebačkog posavlja – in croatian].– geološki vjesnik, 28, 153–164. težak-gregl, t. & vojvoda, p. (1987): staro čiče/gradišće – multilayered settlement [staro čiče/gradišće – višeslojno naselje – in croatian].– arheološki pregled, 27, 46. tite, m.s. (1999): pottery production, distribution, and consumption – the contribution of the physical sciences.journal of archaeological method and theory, 6 (3), 181–233. velde, b. (1992): introduction to clay minerals: chemistry, origins, uses and environmental significance. chapman & hall, hong kong. velde, b. & druc, i.c. (1999): archaeological ceramic materials: origin and utilization, springer. velde, b. & meunier, a. (2008): the origin of clay minerals in soils and weathered rocks. springer. velić, j. (1983): neotectonic relations and development of the western part of the sava basin [neotektonski odnosi i razvitak zapadnog dijela savske potoline – in croatian].– prirodoslovna istraživanja 47, acta geologica 13(2), jugoslavenska akademija znanosti i umjetnosti, zagreb. žibrat gašparič, a. (2004): archaeometrical analysis of neolithic pottery from the divaca region, slovenia.documenta praehistorica, 31. https://doi.org/10.4312/dp.31.15 g eologia c roatica 285neral et al.: tracing the origin of raw materials used for the production of ancient ceramics: a case study of multi-period archaeological sites ... sa m pl e nu m be r sa m pl e ty pe si te si o 2 ( % ) a l 2o 3 (% ) fe 2o 3 (% ) m go (% ) ca o (% ) n a 2 o (% ) k 2 o (% ) ti o 2 (% ) p 2 o 5 (% ) m no (% ) cr 2o 3 (% ) lo i ( % ) su m (% ) 10 5 cl ay sč g 40 .7 8 11 .7 7 3. 23 2. 88 7. 60 0. 62 1. 68 0. 56 0. 17 0. 02 0. 01 30 .5 0 99 .8 7 10 8 cl ay sč g 54 .1 8 13 .0 0 5. 16 3. 37 5. 01 0. 81 1. 88 0. 66 0. 12 0. 02 0. 01 15 .6 0 99 .8 9 14 12 4 cl ay kb 66 .1 0 15 .0 4 5. 68 1. 12 0. 48 0. 88 1. 92 1. 00 0. 09 0. 07 0. 01 7. 40 99 .8 4 14 12 6 cl ay kb 75 .7 8 11 .8 6 2. 26 0. 68 0. 44 0. 74 1. 54 0. 98 0. 04 0. 02 0. 01 5. 50 99 .8 4 14 12 7 cl ay kb 61 .3 9 16 .2 2 5. 71 1. 29 0. 60 0. 76 2. 24 0. 95 0. 15 0. 11 0. 02 10 .4 0 99 .8 3 25 3 ce ra m ic s sč g 58 .2 2 17 .3 2 4. 56 1. 55 3. 87 0. 59 1. 83 0. 59 1. 78 0. 03 0. 01 9. 40 99 .9 1 25 6 ce ra m ic s sč g 62 .5 5 15 .3 9 4. 41 1. 50 4. 21 0. 65 2. 03 0. 63 1. 30 0. 02 0. 01 7.1 0 99 .9 0 25 8 ce ra m ic s sč g 56 .8 3 14 .2 1 3. 89 1. 31 6. 82 0. 76 1. 89 0. 75 2. 63 0. 05 0. 01 10 .6 0 99 .9 1 26 1 ce ra m ic s sč g 53 .7 9 17 .9 6 6. 61 1. 63 2. 56 0. 69 2. 26 0. 77 2. 51 0. 10 0. 02 10 .8 0 99 .8 7 26 4 ce ra m ic s sč g 59 .9 5 18 .0 2 4. 66 1. 08 2. 31 0. 42 2. 06 0. 67 2. 52 0. 04 0. 02 8. 00 99 .9 1 26 5 ce ra m ic s sč g 50 .5 4 17 .3 3 4. 93 1. 66 6. 02 0. 72 1. 94 0. 72 3. 12 0. 10 0. 02 12 .6 0 99 .9 0 27 1 ce ra m ic s sč g 53 .7 5 16 .4 7 8. 15 0. 68 3. 10 0. 38 1. 16 1. 14 2. 61 0. 05 0. 02 12 .3 0 99 .9 2 27 7 ce ra m ic s sč g 34 .0 6 13 .2 4 2. 83 0. 60 20 .13 0. 24 1. 16 0. 61 2. 93 0. 07 0. 01 23 .9 0 99 .9 4 27 8 ce ra m ic s sč g 48 .9 6 19 .5 7 6. 72 1. 17 3. 69 0. 14 1. 30 0. 89 3. 03 0. 04 0. 02 14 .2 0 99 .8 9 28 0 ce ra m ic s sč g 49 .5 2 22 .11 3. 76 0. 99 4. 09 0. 20 1. 60 0. 67 1. 70 0. 03 0. 02 15 .1 0 99 .9 2 28 4 ce ra m ic s sč g 54 .12 18 .2 0 7.1 5 0. 88 2. 34 0. 56 1. 74 1. 00 3. 05 0. 02 0. 02 10 .7 0 99 .9 1 28 5 ce ra m ic s sč g 49 .4 3 11 .2 1 3. 20 0. 68 11 .8 4 0. 59 1. 14 0. 56 4. 17 0. 06 0. 01 16 .9 0 99 .9 4 28 6 ce ra m ic s sč g 55 .2 5 17 .8 2 5. 05 0. 57 2. 86 0. 14 2. 01 0. 89 4. 61 0. 06 0. 01 10 .5 0 99 .9 3 14 13 0 ce ra m ic s kb 47 .5 8 22 .2 3 8. 43 1. 38 0. 87 0. 44 2. 33 0. 85 2. 94 0. 12 0. 02 12 .6 0 99 .7 6 14 13 1 ce ra m ic s kb 43 .4 1 23 .5 1 8. 75 1. 30 1. 96 0. 35 1. 42 0. 97 2. 66 0. 10 0. 02 15 .3 0 99 .7 9 14 13 4 ce ra m ic s kb 46 .3 6 22 .4 7 7. 60 1. 27 1. 07 0. 46 1. 61 0. 85 1. 90 0. 04 0. 02 16 .1 0 99 .7 8 14 13 5 ce ra m ic s kb 46 .6 5 21 .7 3 7. 82 1. 10 1. 16 0. 45 2. 28 0. 90 5. 40 0. 11 0. 02 12 .1 0 99 .7 1 14 13 8 ce ra m ic s kb 51 .8 8 20 .4 3 7. 42 1. 40 0. 84 0. 56 2. 13 0. 91 2. 10 0. 06 0. 02 12 .0 0 99 .7 7 14 13 9 ce ra m ic s kb 49 .7 7 22 .3 2 7. 45 1. 19 0. 95 0. 45 2. 30 0. 96 3. 80 0. 08 0. 02 10 .5 0 99 .7 8 14 14 4 ce ra m ic s kb 46 .4 8 21 .1 4 7. 79 1. 28 1. 25 0. 46 2. 56 0. 86 4. 53 0. 10 0. 02 13 .3 0 99 .7 5 14 14 6 ce ra m ic s kb 51 .13 20 .7 8 7. 05 0. 78 0. 62 0. 53 1. 56 1. 06 0. 82 0. 03 0. 02 15 .5 0 99 .8 3 14 14 7 ce ra m ic s kb 47 .4 0 19 .9 8 7. 32 1. 06 1. 34 0. 49 2. 21 0. 90 5. 26 0. 10 0. 02 13 .6 0 99 .6 7 14 14 8 ce ra m ic s kb 49 .5 7 20 .2 9 7. 36 1. 29 1. 03 0. 50 2. 23 0. 90 4. 31 0. 12 0. 02 12 .1 0 99 .7 2 14 15 0 ce ra m ic s kb 47 .3 7 21 .6 6 6. 96 1. 53 1. 14 0. 45 2. 15 0. 85 3. 84 0. 05 0. 02 13 .7 0 99 .7 1 14 15 1 ce ra m ic s kb 50 .5 7 21 .0 6 5. 15 0. 80 0. 72 0. 29 2. 16 0. 98 3. 68 0. 04 0. 02 14 .3 0 99 .7 7 14 15 2 ce ra m ic s kb 50 .3 1 19 .7 8 6. 83 0. 94 0. 96 0. 54 2. 26 0. 96 4. 67 0. 09 0. 02 12 .4 0 99 .7 4 14 15 4 ce ra m ic s kb 58 .6 9 18 .7 0 4. 81 0. 67 1. 19 0. 79 1. 57 0. 88 0. 41 0. 07 0. 02 12 .0 0 99 .8 4 14 16 0 ce ra m ic s kb 50 .2 6 22 .2 6 8. 12 1. 60 0. 86 0. 34 3. 53 0. 86 0. 54 0. 08 0. 02 11 .3 0 99 .7 9 14 16 1 ce ra m ic s kb 46 .1 9 21 .9 6 7. 46 0. 74 1. 56 0. 35 1. 93 0. 84 0. 87 0. 04 0. 02 17 .9 0 99 .8 5 14 22 3 ce ra m ic s kb 62 .7 5 17 .3 3 4. 58 0. 59 0. 54 0. 71 1. 69 0. 82 0. 65 0. 10 0. 02 10 .1 0 99 .8 6 supplement 1. – geochemical composition of ceramics from staro čiče-gradišće and kurilovec-belinščica sites and of clayey samples collected near the sites (sčg – staro čiče-gradišće; k-b – kurilovec-belinščica) g eo lo gi a c ro at ic a 286 geologia croatica 77/3 sa m pl e nu m be r sa m pl e ty pe si te n i ( pp m ) sc (p pm ) ba (p pm ) be (p pm ) co (p pm ) cs (p pm ) g a (p pm ) h f ( pp m ) n b (p pm ) rb (p pm ) sn (p pm ) sr (p pm ) ta (p pm ) 10 5 cl ay sč g 44 .0 0 11 .0 0 42 6. 00 <1 15 .7 0 6. 70 19 .0 0 4. 20 10 .1 0 86 .8 0 3. 00 94 .2 0 0. 80 10 8 cl ay sč g 38 .0 0 12 .0 0 34 0. 00 1. 00 10 .3 0 5. 60 14 .7 0 5. 10 10 .8 0 96 .8 0 3. 00 81 .8 0 0. 90 14 12 4 cl ay kb 37 .0 0 14 .0 0 44 5. 00 <1 13 .6 0 8. 30 20 .7 0 8. 40 17 .7 0 10 8. 00 4. 00 89 .5 0 1. 20 14 12 6 cl ay kb 27 .0 0 10 .0 0 29 7. 00 2. 00 8. 20 6. 00 13 .8 0 10 .4 0 18 .7 0 87 .9 0 3. 00 77 .5 0 1. 30 14 12 7 cl ay kb 45 .0 0 15 .0 0 28 9. 00 <1 10 .0 0 6. 60 15 .0 0 7. 00 16 .8 0 13 4. 50 4. 00 84 .4 0 1. 30 25 3 ce ra m ic s sč g 50 .0 0 16 .0 0 44 6. 00 2. 00 9. 70 7.1 0 19 .1 0 3. 50 10 .1 0 98 .9 0 4. 00 12 8. 50 0. 80 25 6 ce ra m ic s sč g 37 .0 0 14 .0 0 44 9. 00 4. 00 10 .0 0 6. 60 17 .0 0 3. 80 11 .0 0 95 .6 0 4. 00 11 6. 40 0. 90 25 8 ce ra m ic s sč g 33 .0 0 13 .0 0 76 8. 00 6. 00 10 .5 0 5. 00 14 .3 0 5. 40 12 .3 0 86 .9 0 3. 00 18 2. 20 1. 10 26 1 ce ra m ic s sč g 74 .0 0 17 .0 0 73 8. 00 7. 00 14 .3 0 8. 70 19 .5 0 4. 70 12 .6 0 12 6. 90 5. 00 15 5. 60 0. 80 26 4 ce ra m ic s sč g 59 .0 0 16 .0 0 78 9. 00 <1 10 .9 0 7. 60 18 .9 0 3. 80 11 .5 0 99 .4 0 4. 00 14 3. 10 0. 90 26 5 ce ra m ic s sč g 73 .0 0 17 .0 0 96 3. 00 1. 00 12 .6 0 6. 20 18 .9 0 4. 80 12 .4 0 89 .7 0 4. 00 18 1. 40 1. 00 27 1 ce ra m ic s sč g 36 .0 0 18 .0 0 55 7. 00 2. 00 10 .0 0 5. 00 18 .6 0 6. 30 14 .9 0 61 .1 0 3. 00 14 2. 90 1. 20 27 7 ce ra m ic s sč g 40 .0 0 13 .0 0 71 9. 00 <1 5. 40 5. 20 15 .0 0 3. 40 11 .0 0 85 .0 0 3. 00 18 7. 40 0. 80 27 8 ce ra m ic s sč g 88 .0 0 18 .0 0 91 1. 00 3. 00 12 .9 0 8. 10 22 .9 0 3. 80 15 .0 0 74 .3 0 5. 00 16 0. 20 1. 10 28 0 ce ra m ic s sč g 61 .0 0 19 .0 0 64 7. 00 5. 00 11 .2 0 8. 40 25 .5 0 3. 90 11 .9 0 10 1. 00 5. 00 11 4. 50 0. 80 28 4 ce ra m ic s sč g 43 .0 0 17 .0 0 77 8. 00 3. 00 5. 40 7. 70 20 .5 0 7. 40 18 .2 0 90 .3 0 4. 00 12 5. 50 1. 40 28 5 ce ra m ic s sč g 32 .0 0 10 .0 0 93 5. 00 <1 7. 60 3. 30 10 .9 0 3. 40 9. 00 49 .9 0 3. 00 21 1. 40 0. 80 28 6 ce ra m ic s sč g 23 .0 0 18 .0 0 88 9. 00 3. 00 4. 70 4. 30 19 .1 0 5. 90 16 .3 0 67 .3 0 6. 00 15 5. 00 1. 20 14 13 0 ce ra m ic s kb 99 .0 0 21 .0 0 94 8. 00 <1 21 .1 0 11 .0 0 27 .7 0 4. 00 15 .2 0 14 4. 80 4. 00 94 .8 0 0. 90 14 13 1 ce ra m ic s kb 63 .0 0 21 .0 0 61 9. 00 2. 00 21 .7 0 5. 20 24 .3 0 4. 90 17 .1 0 70 .1 0 5. 00 92 .8 0 1. 40 14 13 4 ce ra m ic s kb 10 3. 00 21 .0 0 79 5. 00 5. 00 15 .8 0 10 .1 0 27 .2 0 4. 80 15 .2 0 11 7. 50 5. 00 79 .9 0 1. 10 14 13 5 ce ra m ic s kb 61 .0 0 21 .0 0 13 74 .0 0 6. 00 16 .4 0 8. 10 26 .0 0 5. 10 16 .5 0 12 2. 10 5. 00 15 0. 30 1. 30 14 13 8 ce ra m ic s kb 87 .0 0 20 .0 0 84 0. 00 4. 00 15 .6 0 9. 80 24 .4 0 5. 40 16 .7 0 13 6. 80 4. 00 88 .2 0 1. 10 14 13 9 ce ra m ic s kb 64 .0 0 21 .0 0 77 3. 00 6. 00 15 .6 0 7. 70 25 .6 0 5. 20 16 .1 0 11 3. 50 5. 00 10 3. 90 1. 50 14 14 4 ce ra m ic s kb 74 .0 0 21 .0 0 10 65 .0 0 3. 00 15 .1 0 10 .0 0 25 .4 0 4. 50 14 .9 0 13 6. 60 4. 00 13 8. 30 1. 10 14 14 6 ce ra m ic s kb 82 .0 0 19 .0 0 55 7. 00 5. 00 9. 80 8. 90 23 .2 0 6. 40 19 .2 0 89 .9 0 5. 00 59 .8 0 1. 40 14 14 7 ce ra m ic s kb 70 .0 0 19 .0 0 17 24 .0 0 3. 00 15 .5 0 8. 80 24 .1 0 5. 10 16 .9 0 12 9. 50 5. 00 17 8. 60 1. 20 14 14 8 ce ra m ic s kb 74 .0 0 20 .0 0 13 04 .0 0 2. 00 18 .9 0 9. 40 25 .8 0 5. 50 16 .3 0 13 7. 00 5. 00 13 8. 00 1. 20 14 15 0 ce ra m ic s kb 97 .0 0 21 .0 0 13 39 .0 0 5. 00 14 .1 0 10 .7 0 26 .5 0 4. 50 14 .6 0 14 1. 60 4. 00 11 6. 50 1. 10 14 15 1 ce ra m ic s kb 63 .0 0 19 .0 0 93 9. 00 6. 00 10 .5 0 7. 80 24 .3 0 6. 10 17 .3 0 10 3. 60 4. 00 93 .3 0 1. 10 14 15 2 ce ra m ic s kb 73 .0 0 20 .0 0 10 84 .0 0 1. 00 17 .8 0 9. 50 23 .9 0 6. 40 19 .0 0 13 2. 50 4. 00 15 2. 20 1. 10 14 15 4 ce ra m ic s kb 57 .0 0 15 .0 0 46 8. 00 3. 00 11 .4 0 5. 60 19 .1 0 6. 90 15 .1 0 79 .8 0 4. 00 77 .6 0 1. 20 14 16 0 ce ra m ic s kb 11 6. 00 21 .0 0 70 4. 00 5. 00 16 .9 0 11 .8 0 25 .7 0 4. 40 15 .6 0 13 2. 70 5. 00 61 .2 0 1. 20 14 16 1 ce ra m ic s kb 66 .0 0 18 .0 0 40 9. 00 2. 00 11 .5 0 6. 50 22 .6 0 4. 80 14 .7 0 85 .0 0 4. 00 50 .8 0 1. 00 14 22 3 ce ra m ic s kb 69 .0 0 15 .0 0 48 8. 00 2. 00 13 .7 0 6. 10 19 .0 0 5. 70 14 .3 0 82 .6 0 3. 00 60 .7 0 1. 00 supplement 1. – continued g eologia c roatica 287neral et al.: tracing the origin of raw materials used for the production of ancient ceramics: a case study of multi-period archaeological sites ... sa m pl e nu m be r sa m pl e ty pe si te th (p pm ) u (p pm ) v (p pm ) w (p pm ) zr (p pm ) y (p pm ) la (p pm ) ce (p pm ) pr (p pm ) n d (p pm ) sm (p pm ) eu (p pm ) g d (p pm ) 10 5 cl ay sč g 10 .5 0 3. 90 94 .0 0 1. 30 14 6. 10 25 .2 0 30 .0 0 57 .9 0 6. 77 25 .3 0 4. 85 0. 96 4. 60 10 8 cl ay sč g 11 .7 0 2. 70 92 .0 0 2. 50 18 5. 30 29 .0 0 32 .6 0 63 .2 0 7. 37 28 .0 0 5. 67 1. 15 5. 17 14 12 4 cl ay kb 12 .5 0 3. 80 12 1. 00 2. 20 33 8. 20 32 .9 0 40 .2 80 .8 0 9. 52 36 .0 0 6. 73 1. 44 6. 42 14 12 6 cl ay kb 11 .7 0 3. 60 87 .0 0 2. 70 40 0. 60 30 .5 0 41 .9 0 79 .8 0 8. 86 34 .0 0 6. 07 1. 18 5. 36 14 12 7 cl ay kb 13 .4 0 3. 60 12 8. 00 2. 90 25 0. 40 31 .3 0 42 .1 0 81 .6 0 9. 67 36 .6 0 7. 01 1. 37 6. 37 25 3 ce ra m ic s sč g 13 .6 0 3. 40 92 .0 0 1. 60 11 4. 00 27 .2 0 34 .3 0 65 .7 0 7. 73 28 .9 0 5. 87 1. 15 5. 32 25 6 ce ra m ic s sč g 13 .6 0 3. 50 95 .0 0 1. 60 14 3. 10 25 .6 0 34 .1 0 65 .1 0 7. 79 30 .0 0 5. 69 1. 14 5. 15 25 8 ce ra m ic s sč g 12 .7 0 2. 90 78 .0 0 1. 80 20 2. 50 31 .9 0 39 .2 0 74 .1 0 9. 06 35 .0 0 6. 77 1. 38 5. 99 26 1 ce ra m ic s sč g 16 .3 0 3. 00 10 7. 00 2. 00 17 3. 20 32 .8 0 41 .1 0 80 .0 0 9. 67 36 .2 0 7.1 3 1. 41 6. 52 26 4 ce ra m ic s sč g 13 .5 0 3. 50 15 2. 00 2. 20 13 4. 70 28 .0 0 36 .6 0 68 .1 0 8. 38 31 .9 0 6. 32 1. 26 5. 51 26 5 ce ra m ic s sč g 15 .8 0 2. 70 10 7. 00 1. 90 18 5. 20 34 .8 0 42 .9 0 82 .5 0 9. 90 37 .8 0 7. 20 1. 54 7. 00 27 1 ce ra m ic s sč g 12 .5 0 2. 80 14 0. 00 3. 20 25 3. 40 27 .4 0 31 .3 0 66 .0 0 7.1 7 27 .1 0 5. 41 1. 04 4. 83 27 7 ce ra m ic s sč g 14 .4 0 2. 70 89 .0 0 1. 90 14 2. 20 18 .1 0 34 .5 0 64 .8 0 7. 58 27 .5 0 4. 97 1. 03 3. 99 27 8 ce ra m ic s sč g 12 .8 0 4. 70 14 5. 00 2. 10 14 2. 10 22 .6 0 37 .9 0 70 .7 0 8. 16 30 .5 0 5. 45 1. 02 4. 40 28 0 ce ra m ic s sč g 15 .5 0 3. 60 13 3. 00 2. 00 14 2. 10 25 .5 0 33 .1 0 62 .6 0 7.1 5 26 .7 0 5. 06 1. 01 4. 70 28 4 ce ra m ic s sč g 21 .1 0 3. 70 13 0. 00 4. 10 28 5. 10 25 .7 0 36 .8 0 76 .1 0 8. 20 31 .1 0 5. 61 1. 02 4. 98 28 5 ce ra m ic s sč g 8. 40 2. 10 55 .0 0 1. 80 13 7. 30 17 .8 0 23 .3 0 43 .3 0 5. 20 19 .7 0 3. 88 0. 73 3. 24 28 6 ce ra m ic s sč g 12 .3 0 3. 70 11 7. 00 2. 40 21 4. 40 16 .9 0 32 .6 0 79 .9 0 6. 62 22 .9 0 4. 17 0. 78 3. 39 14 13 0 ce ra m ic s kb 15 .8 0 4. 30 16 3. 00 2. 90 14 7.1 0 35 .4 0 45 .8 0 84 .4 0 10 .7 4 42 .5 0 8. 33 1. 68 7. 82 14 13 1 ce ra m ic s kb 17 .7 0 3. 40 17 1. 00 2. 70 17 9. 40 39 .1 0 52 .0 0 97 .0 0 12 .0 9 46 .7 0 9. 49 1. 91 8. 77 14 13 4 ce ra m ic s kb 15 .2 0 4. 30 16 6. 00 2. 20 17 8. 30 32 .3 0 38 .6 0 74 .6 0 9. 69 37 .2 0 7. 42 1. 55 7. 20 14 13 5 ce ra m ic s kb 16 .0 0 4. 90 14 4. 00 2. 50 18 6. 00 36 .7 0 48 .1 0 86 .5 0 11 .3 8 43 .7 0 8. 64 1. 82 8. 08 14 13 8 ce ra m ic s kb 15 .5 0 3. 80 16 1. 00 1. 60 19 8. 00 37 .3 0 45 .0 0 82 .8 0 11 .0 0 40 .7 0 8. 44 1. 71 8. 00 14 13 9 ce ra m ic s kb 16 .2 0 4. 50 15 0. 00 2. 90 19 1. 40 38 .6 0 46 .5 0 89 .3 0 11 .5 4 43 .5 0 8. 66 1. 70 8. 18 14 14 4 ce ra m ic s kb 14 .6 0 3. 60 15 6. 00 2. 10 15 5. 30 37 .5 0 45 .1 0 82 .3 0 10 .5 8 39 .7 0 7. 90 1. 68 7. 72 14 14 6 ce ra m ic s kb 17 .6 0 4. 60 16 5. 00 2. 60 23 8. 20 28 .3 0 34 .2 0 65 .6 0 8. 34 33 .0 0 6. 25 1. 30 5. 70 14 14 7 ce ra m ic s kb 15 .1 0 4. 30 14 9. 00 2. 40 18 7. 40 42 .4 0 54 .0 0 90 .7 0 12 .6 1 48 .2 0 9. 24 2. 00 9. 21 14 14 8 ce ra m ic s kb 15 .1 0 4. 30 14 3. 00 2. 10 18 9. 60 41 .5 0 50 .6 0 92 .8 0 12 .0 0 45 .7 0 9. 09 1. 91 8. 59 14 15 0 ce ra m ic s kb 14 .9 0 4. 30 15 6. 00 2. 40 15 7.1 0 37 .9 0 46 .6 0 83 .3 0 10 .8 1 43 .0 0 8. 16 1. 61 7. 76 14 15 1 ce ra m ic s kb 15 .8 0 3. 70 13 6. 00 2. 50 21 5. 50 36 .8 0 47 .0 0 87 .1 0 10 .8 9 41 .6 0 8. 35 1. 57 7. 75 14 15 2 ce ra m ic s kb 16 .1 0 5. 10 13 9. 00 2. 40 22 4. 30 41 .6 0 54 .0 0 10 1. 90 11 .8 3 45 .9 0 8. 44 1. 74 8. 32 14 15 4 ce ra m ic s kb 14 .0 0 10 .3 0 13 0. 00 2. 10 24 0. 80 34 .1 0 36 .9 0 71 .3 0 8. 83 34 .6 0 7. 08 1. 43 6. 61 14 16 0 ce ra m ic s kb 17 .7 0 4. 40 14 5. 00 2. 40 15 9. 80 29 .9 0 34 .1 0 68 .6 0 8. 66 33 .5 0 7.1 6 1. 47 6. 43 14 16 1 ce ra m ic s kb 15 .7 0 9. 20 14 4. 00 2. 20 16 8. 10 35 .4 0 43 .4 0 76 .2 0 10 .2 0 38 .8 0 8. 23 1. 59 7. 22 14 22 3 ce ra m ic s kb 12 .6 0 5. 20 12 2. 00 1. 90 20 3. 50 29 .5 0 34 .6 0 75 .5 0 8. 28 31 .6 0 6. 35 1. 28 5. 86 supplement 1. – continued g eo lo gi a c ro at ic a 288 geologia croatica 77/3 sa m pl e nu m be r sa m pl e ty pe si te tb (p pm ) d y (p pm ) h o (p pm ) er (p pm ) tm (p pm ) yb (p pm ) lu (p pm ) m o (p pm ) cu (p pm ) pb (p pm ) zn (p pm ) n i ( pp m ) a s ( pp m ) 10 5 cl ay sč g 0. 72 4. 35 0. 87 2. 53 0. 36 2. 38 0. 37 0. 60 32 .0 0 21 .1 0 72 .0 0 30 .3 0 2. 40 10 8 cl ay sč g 0. 83 5. 08 1. 03 2. 94 0. 41 2. 61 0. 40 0. 70 18 .8 0 18 .8 0 61 .0 0 29 .3 0 9. 40 14 12 4 cl ay kb 1. 02 5. 96 1. 18 3. 49 0. 54 3. 38 0. 51 0. 50 17 .1 0 18 .4 0 60 .0 0 23 .9 0 11 .0 0 14 12 6 cl ay kb 0. 90 5. 22 1. 08 3. 39 0. 47 3. 20 0. 52 0. 10 9. 80 13 .3 0 30 .0 0 11 .6 0 1. 80 14 12 7 cl ay kb 1. 01 5. 81 1. 20 3. 27 0. 49 3. 15 0. 49 0. 50 19 .0 0 27 .1 0 71 .0 0 31 .0 0 10 .5 0 25 3 ce ra m ic s sč g 0. 80 4. 71 0. 92 2. 69 0. 39 2. 55 0. 37 0. 30 23 .7 0 16 .5 0 11 6. 00 33 .8 0 3. 80 25 6 ce ra m ic s sč g 0. 77 4. 59 0. 92 2. 76 0. 34 2. 56 0. 35 0. 30 20 .5 0 16 .7 0 94 .0 0 32 .4 0 3. 60 25 8 ce ra m ic s sč g 0. 91 5. 35 1. 16 3. 16 0. 45 2. 89 0. 45 0. 40 24 .3 0 15 .3 0 13 3. 00 30 .3 0 4. 00 26 1 ce ra m ic s sč g 0. 98 6. 04 1. 16 3. 36 0. 47 3. 06 0. 45 1. 10 35 .4 0 21 .7 0 17 5. 00 61 .7 0 12 .1 0 26 4 ce ra m ic s sč g 0. 83 5. 07 0. 94 2. 89 0. 40 2. 66 0. 39 0. 30 23 .8 0 17 .7 0 11 0. 00 35 .0 0 6. 60 26 5 ce ra m ic s sč g 1. 02 6. 21 1. 19 3. 45 0. 46 3. 12 0. 47 0. 40 38 .3 0 19 .0 0 15 5. 00 48 .0 0 12 .8 0 27 1 ce ra m ic s sč g 0. 77 5. 15 0. 99 3. 01 0. 44 2. 88 0. 43 0. 60 25 .9 0 19 .1 0 61 .0 0 29 .5 0 11 .8 0 27 7 ce ra m ic s sč g 0. 60 3. 54 0. 66 1. 83 0. 24 1. 87 0. 26 0. 20 21 .1 0 16 .9 0 75 .0 0 27 .1 0 7. 40 27 8 ce ra m ic s sč g 0. 65 3. 93 0. 76 2. 40 0. 35 2. 26 0. 33 0. 50 22 .7 0 23 .9 0 15 9. 00 63 .5 0 10 .3 0 28 0 ce ra m ic s sč g 0. 71 4. 44 0. 83 2. 74 0. 38 2. 60 0. 35 0. 10 26 .0 0 18 .9 0 11 2. 00 31 .6 0 10 .0 0 28 4 ce ra m ic s sč g 0. 72 4. 36 0. 87 2. 67 0. 36 2. 54 0. 37 0. 20 13 .6 0 20 .2 0 97 .0 0 37 .0 0 40 .0 0 28 5 ce ra m ic s sč g 0. 47 3. 07 0. 56 1. 74 0. 23 1. 58 0. 23 0. 40 18 .8 0 12 .8 0 95 .0 0 29 .3 0 9. 80 28 6 ce ra m ic s sč g 0. 51 3. 18 0. 61 1. 89 0. 26 1. 77 0. 25 1. 00 12 .0 0 25 .0 0 76 .0 0 20 .3 0 20 .7 0 14 13 0 ce ra m ic s kb 1. 22 6. 84 1. 25 3. 77 0. 56 3. 58 0. 53 0. 40 56 .6 0 34 .8 0 13 1. 00 79 .0 0 13 .6 0 14 13 1 ce ra m ic s kb 1. 32 7. 63 1. 48 4. 29 0. 62 4. 16 0. 59 0. 30 32 .6 0 36 .0 0 88 .0 0 42 .1 0 11 .0 0 14 13 4 ce ra m ic s kb 1. 13 6. 38 1. 22 3. 58 0. 50 3. 34 0. 51 0. 40 40 .0 0 28 .6 0 12 1. 00 75 .6 0 11 .7 0 14 13 5 ce ra m ic s kb 1. 25 7.1 8 1. 41 4. 07 0. 60 3. 89 0. 56 0. 40 26 .6 0 26 .4 0 12 5. 00 44 .3 0 8. 30 14 13 8 ce ra m ic s kb 1. 24 6. 89 1. 32 4. 04 0. 58 3. 63 0. 58 0. 40 29 .2 0 26 .0 0 11 0. 00 60 .3 0 11 .6 0 14 13 9 ce ra m ic s kb 1. 24 7. 03 1. 46 3. 83 0. 61 3. 91 0. 59 0. 30 24 .4 0 27 .9 0 87 .0 0 41 .1 0 9. 00 14 14 4 ce ra m ic s kb 1. 18 6. 62 1. 36 3. 80 0. 57 3. 56 0. 58 0. 60 38 .9 0 33 .0 0 13 5. 00 62 .4 0 16 .0 0 14 14 6 ce ra m ic s kb 0. 85 5. 13 1. 03 2. 89 0. 44 2. 82 0. 44 0. 30 28 .1 0 25 .2 0 60 .0 0 56 .6 0 15 .9 0 14 14 7 ce ra m ic s kb 1. 39 7. 56 1. 50 4. 07 0. 62 4. 14 0. 54 0. 40 41 .8 0 28 .7 0 13 1. 00 56 .8 0 10 .0 0 14 14 8 ce ra m ic s kb 1. 34 7.1 2 1. 45 3. 98 0. 62 4. 00 0. 61 0. 40 36 .6 0 30 .3 0 12 8. 00 59 .2 0 10 .7 0 14 15 0 ce ra m ic s kb 1. 22 6. 84 1. 33 3. 77 0. 56 3. 55 0. 55 0. 40 40 .0 0 29 .4 0 14 7. 00 73 .6 0 10 .9 0 14 15 1 ce ra m ic s kb 1. 23 6. 96 1. 48 4. 14 0. 59 3. 79 0. 59 0. 20 39 .6 0 27 .9 0 83 .0 0 38 .6 0 11 .7 0 14 15 2 ce ra m ic s kb 1. 23 6. 98 1. 47 4. 17 0. 56 3. 83 0. 58 0. 40 31 .2 0 25 .8 0 10 3. 00 50 .1 0 11 .9 0 14 15 4 ce ra m ic s kb 1. 01 5. 91 1. 22 3. 55 0. 49 3. 20 0. 51 0. 20 24 .1 0 29 .2 0 68 .0 0 44 .0 0 8. 20 14 16 0 ce ra m ic s kb 1. 06 6. 08 1. 23 3. 35 0. 51 3. 47 0. 53 1. 20 39 .3 0 39 .9 0 15 0. 00 10 2. 80 9. 60 14 16 1 ce ra m ic s kb 1. 17 6. 40 1. 29 3. 69 0. 55 3. 59 0. 53 0. 20 36 .9 0 34 .8 0 11 6. 00 59 .7 0 8. 20 14 22 3 ce ra m ic s kb 0. 94 5. 07 1. 08 3. 14 0. 44 3. 06 0. 47 0. 20 21 .2 0 25 .1 0 67 .0 0 44 .2 0 10 .3 0 supplement 1. – continued g eologia c roatica 289neral et al.: tracing the origin of raw materials used for the production of ancient ceramics: a case study of multi-period archaeological sites ... sa m pl e nu m be r sa m pl e ty pe si te cd (p pm ) sb (p pm ) bi (p pm ) a g (p pm ) a u (p pm ) h g (p pm ) tl (p pm ) se (p pm ) 10 5 cl ay sč g 0. 50 0. 30 0. 30 <0 .1 2. 10 0. 13 0. 10 5. 90 10 8 cl ay sč g 0. 20 0. 30 0. 20 <0 .1 1. 80 0. 10 0. 10 0. 80 14 12 4 cl ay kb <0 ,1 0. 40 0. 30 <0 ,1 2. 20 0. 08 0. 20 <0 ,5 14 12 6 cl ay kb <0 ,1 0. 20 0. 20 <0 ,1 2. 30 0. 05 0. 20 <0 ,5 14 12 7 cl ay kb 0. 30 0. 30 0. 30 <0 ,1 1. 80 0. 08 0. 20 0. 80 25 3 ce ra m ic s sč g 0. 20 0. 10 0. 30 <0 .1 0. 80 <0 .0 1 0. 30 <0 .5 25 6 ce ra m ic s sč g 0. 20 0. 20 0. 10 <0 .1 <0 .5 0. 02 0. 30 <0 .5 25 8 ce ra m ic s sč g 0. 50 0. 20 0. 10 <0 .1 1. 00 0. 02 0. 20 <0 .5 26 1 ce ra m ic s sč g 0. 80 0. 20 0. 30 <0 .1 1. 00 0. 04 0. 20 <0 .5 26 4 ce ra m ic s sč g 0. 30 0. 20 0. 20 <0 .1 0. 80 0. 02 0. 30 <0 .5 26 5 ce ra m ic s sč g 0. 60 0. 20 0. 20 <0 .1 3. 00 0. 03 0. 20 <0 .5 27 1 ce ra m ic s sč g 0. 30 0. 40 0. 20 <0 .1 1. 10 0. 02 0. 20 <0 .5 27 7 ce ra m ic s sč g 0. 50 <0 .1 0. 20 <0 .1 1. 00 0. 03 0. 20 <0 .5 27 8 ce ra m ic s sč g 0. 50 <0 .1 0. 30 <0 .1 1. 00 0. 03 0. 30 <0 .5 28 0 ce ra m ic s sč g 0. 30 <0 .1 0. 30 <0 .1 1. 60 0. 02 0. 30 <0 .5 28 4 ce ra m ic s sč g 0. 30 0. 10 0. 40 <0 .1 0. 70 0. 14 0. 20 <0 .5 28 5 ce ra m ic s sč g 0. 80 0. 20 0. 20 <0 .1 2. 20 0. 05 0. 20 <0 .5 28 6 ce ra m ic s sč g 0. 40 0. 30 <0 .1 <0 .1 2. 30 0. 04 0. 20 <0 .5 14 13 0 ce ra m ic s kb 0. 50 0. 20 0. 50 0. 10 2. 30 0. 02 0. 30 0. 60 14 13 1 ce ra m ic s kb 0. 60 0. 40 <0 ,1 0. 10 1. 80 0. 02 0. 30 <0 ,5 14 13 4 ce ra m ic s kb 0. 30 0. 20 0. 40 0. 10 1. 00 0. 01 0. 30 0. 50 14 13 5 ce ra m ic s kb 0. 50 0. 30 <0 ,1 <0 ,1 1. 20 0. 01 0. 40 <0 ,5 14 13 8 ce ra m ic s kb 0. 40 0. 20 0. 40 <0 ,1 2. 80 0. 02 0. 30 0. 80 14 13 9 ce ra m ic s kb 0. 30 0. 30 0. 20 0. 10 1. 70 0. 03 0. 40 0. 60 14 14 4 ce ra m ic s kb 0. 70 0. 20 0. 40 0. 10 1. 10 0. 02 0. 30 0. 70 14 14 6 ce ra m ic s kb 0. 30 0. 20 0. 30 0. 10 2. 30 0. 01 0. 30 <0 ,5 14 14 7 ce ra m ic s kb 0. 80 0. 20 0. 30 <0 ,1 1. 40 0. 02 0. 30 0. 50 14 14 8 ce ra m ic s kb 0. 70 0. 20 0. 30 <0 ,1 <0 ,5 0. 02 0. 30 0. 70 14 15 0 ce ra m ic s kb 0. 60 0. 10 0. 40 0. 10 2. 00 0. 02 0. 30 0. 60 14 15 1 ce ra m ic s kb 0. 40 0. 20 <0 ,1 0. 10 1. 20 0. 03 0. 20 <0 ,5 14 15 2 ce ra m ic s kb 0. 50 0. 20 0. 20 <0 ,1 0. 90 0. 02 0. 40 <0 ,5 14 15 4 ce ra m ic s kb 0. 30 0. 20 0. 30 <0 ,1 2. 60 0. 03 0. 30 0. 50 14 16 0 ce ra m ic s kb 0. 80 0. 20 0. 40 <0 ,1 2. 80 <0 ,0 1 0. 50 <0 ,5 14 16 1 ce ra m ic s kb 0. 40 0. 50 <0 ,1 <0 ,1 1. 40 0. 02 0. 20 0. 60 14 22 3 ce ra m ic s kb 0. 20 0. 20 0. 20 <0 ,1 0. 60 0. 02 0. 20 <0 ,5 supplement 1. – continued 2017 | 70/3 | 163–177 | 7 figs. | 1 tab. | 5 pls. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the lycian nappes consist of nappe piles and they tectonically overlie the relatively autochthonous metamorphosed menderes massif to the w–nw and the unmetamorphosed bey dağları autochthon to the e–se (fig. 1) in sw turkey (de graciansky, 1972; özgül, 1976; poisson, 1977; gutnic et al., 1979; şengör & yilmaz, 1981; şenel, 1991; 1997a, b, 2007; collins & robertson, 1998, 2003; okay & tüysüz, 1999; göncüoğlu, 2011; pourteau et al., 2016). the lycian nappe packages comprise several tectono-sedimentary units, which are dominated by thick mesozoic carbonate rocks and are tectonically overlain by ophiolite nappes (de graciansky, 1972; özgül, 1976; şenel, 1997a, b, özer et al., 2015, etc.). tectono-stratigraphic characteristics and the direction and timing of the translation of the lycian nappe piles have been studied in detail for almost 50 years by several researchers as the allochthon is unique in the eastern mediterranean region in having an extensive, well-preserved deformation record (collins & robertson, 1998). because of the complex geological history of the lycian nappes, the original positions of the nappe sequences are still debated. some authors favour a northern origin (north of the menderes platform) for all the nappe piles (de graciansky, 1968, 1972; gutnic et al., 1979; şengör & yilmaz, 1981; collins & robertson, 1997, 1998, 1999; lithostratigraphy and planktonic foraminifera of the uppermost cretaceous–upper palaeocene strata of the tavas nappe of the lycian nappes (sw turkey) bilal sarı dokuz eylül university, faculty of engineering, department of geological engineering, tınaztepe campus, 35160, buca-i̇zmir, turkey; (bilal.sari@deu.edu.tr) doi: 10.4154/gc.2017.14 abstract the lycian nappes lying on top of the para-autochthonous metamorphosed menderes and unmetamorphosed bey dağları successions in sw anatolia belong to the tauride segment of the anatolide-tauride block. the tavas nappe is one of several nappe slices of the lycian nappes and forms structurally the lowermost tectono-stratigraphic unit. the upper part of the tavas nappe succession is represented by planktonic foraminifera-bearing uppermost cretaceous cherty micritic limestones and calciturbidites of the babadağ formation and lower palaeogene micritic limestones and calciclastic rocks of the faralya formation in the study area. lithostratigraphic characteristics and planktonic foraminiferal assemblages of the two formations in the bozburun hill locality (s of köyceğiz) are documented for the first time in three stratigraphic sections in this study. the uppermost part of the babadağ formation mainly comprises of alternating calciclastic and micritic limestones, which include diverse planktonic foraminiferal assemblages of mainly keeled morphotypes. the presence of racemiguembelina fructicosa and abathomphalus mayaroensis within the assemblages indicates a late maastrichtian age for the uppermost part of the succession. two sections of the overlying faralya formation comprise mainly planktonic foraminifera-bearing laminated micritic limestones, brecciated limestones and mudstones. planktonic foraminiferal assemblages of the laminated micritic limestones are dominated by keeled late palaeocene morphotypes. the occurrence of morozovella acuta and globanomalina planoconica at the base of two sections suggests a thanetian age for the deposits. the boundary between the babadağ and faralya formations is characterized by a stratigraphic gap ranging from the latest maastrichtian to the earliest selandian. the gap was linked with the first of the three main events, when ophiolite obduction and incorporation of the köyceğiz thrust sheet into the lycian allochthon occured. cretaceous limestone clasts and foraminifers within the thanetian calciclastic rocks of the faralya formation could be clues to that exposure and erosion. article history: manuscript received june 06, 2017 revised manuscript accepted october 04, 2017 available online october 31, 2017 keywords: late cretaceous, maastrichtian, palaeocene, babadağ formation, faralya formation, tavas nappe, lycian nappes, sw turkey göncüoğlu, 2011), while some suggest a dual origin, which explains the root of the nappe piles originating from two basins, one located to the north of the menderes platform and the other located between the menderes and the bey dağları platforms (poisson, 1984; okay, 1989; özkaya, 1990, 1991; collins & robertson, 2003; arslan et al., 2013). several names have been ascribed for the same nappe piles through the years. a brief summary of names attributed for the tavas nappe is given in table 1. the tavas nappe (şenel, 1997a), (the lowermost tectono-stratigraphic unit of the lycian nappes) comprises table 1. correlation of several names attributed to the tavas nappe. graciansky (1972) karadere serie, tekedere serie, haticeana serie poisson (1977) boz dağ massif erakman et al. (1982) darıyer serie, ahat serie, haticeana serie konak et al. (1987) tavas unit okay (1989) göbecik tepe unit özkaya (1990) tavas thrust slice şenel et al. (1994) tavas nappe collins & robertson (1998) pourteau et al. (2016) teke dere nappe collins & robertson (2003) teke dere thrust sheet g eo lo gi a c ro at ic a geologia croatica 70/3164 upper devonian–norian karadağ serie and upper carboniferous–middle permian tekedere serie at the base and unconformably overlies the rhaetian–middle eocene haticeana serie (de graciansky, 1968, 1972; şenel, 1997a, b; moix et al., 2013). the upper part of the tavas nappe succession is represented by planktonic foraminifera-bearing uppermost cretaceous calciturbidites (babadağ formation) and lower palaeogene micritic limestones overlying flysch-type rocks (faralya formation) in the vicinity of fethiye (şenel, 1997a; gül, 2015). similar rocks are observed to the ne of the lycian nappes in the south figure 1. a) the main tectonostratigraphic zones of turkey (after görür & tüysüz, 2001). lycian nappes represents the westernmost part of the anatolide-tauride block, b) simplified geological map of sw turkey, showing main tectonostratigraphic units and location of the study area (after şenel, 1997a), c) geological map of bozburun hill and surroundings, showing the studied units of the babadağ and faralya formations and locations of the studied sections (simplified after şenel, 1997a). g eologia c roatica sarı bilal: lithostratigraphy and planktonic foraminifera of the uppermost cretaceous–upper palaeocene strata of the tavas ... 165 and east of denizli (i.e. kızılca village and honaz mountain) (poisson, 1984; okay, 1989) and were accepted as the deposits of the kızılca-çorakgöl trough (or intra-tauric trough) which opened between the menderes and bey dağları platforms (poisson & sarp, 1977; poisson, 1977; poisson, 1984; okay, 1989; collins & robertson, 2003). the basin was connected with the ionian trough (greece) to the west according to poisson (1984). a possible connection with the antalya ocean (or pamphylia ocean) through the north of the isparta angle was also claimed (poisson, 1984; şenel, 1991). although the uppermost cretaceous–lower palaeogene successions mentioned above are important as they yield valuable palaeontological data, they have been subject to a few studies, which provide some lists of foraminifera but without illustrations (e.g. şenel, 1991). the aim of this study is to document the lithostratigraphic characteristics and planktonic foraminiferal assemblages of the uppermost levels of the babadağ fm. and the lowermost part of the faralya fm. in and around bozburun hill (south of köyceğiz town) by the means of three measured stratigraphic sections (fig. 1). lithostratigraphic and depositional characteristics of the carbonate dominated rocks and planktonic foraminiferal assemblages of the successions in this locality have not been previously documented. 2. materials and methods this study is based on three stratigraphic sections measured from the bozburun hill locality (fig. 1). planktonic foraminifera were studied in thin section as the standard washed-sample methods (hydrogen peroxide and acetic acid) did not work due to hardness of the limestones of the babadağ fm. and the micritic and clayey limestones of the faralya fm. thin section analysis as a method has been widely used in planktonic foraminifera studies especially for the cretaceous with a high degree of confidence (see sari, 2009, 2013 for the literature). the position of apertures and the presence of supplementary and accessory structures which were later used for generic distinctions are not identifiable in thin section (caron, 1985). however, most of the diagnostic criteria including the size and shape of the test, thickness of the wall, size, shape, number and arrangements of chambers, form and position of the aperture, and forms of ornamentation such as ridges, spines, the position and number of peripheral thickenings or keels can be recognized in axial and subaxial sections (section passing through or parallel to the axis of coiling) (sliter, 1989) are usable data forms. unfortunately, there have been a limited number of attempts to study palaeocene planktonic foraminifera from thin section (e.g. postuma, 1971; van konijnenburg et al., 1998; sari, 2013; sarigül et al., 2017). the resolution of thin-section zonation is nearly as precise as zonal schemes based on isolated specimens for the cretaceous (sliter, 1989). the latest cretaceous planktonic foraminiferal zonation of the classical tethyan gubbio section (italy) has recently been reviewed by coccioni & premoli silva (2015), and they also discuss several planktonic foraminiferal bioevents. the late cretaceous traditional zonations and bioevents developed and refined by many researchers (i.e. robaszynski et al., 1984; caron, 1985; sliter, 1989; premoli silva & sliter, 1994; robaszynski & caron, 1995; li & keller, 1998 a, b; robaszynski, 1998; premoli silva & sliter, 1999; robaszynski et al., 2000; petrizzo, 2003; premoli silva & verga, 2004; huber et al., 2008; pérez rodríguez et al., 2012 etc.) for almost 30 years have lately been adjusted to an updated time scale (ogg & hinnow, 2012; anthonissen & ogg, 2012). van konijnenburg et al. (1998) showed that the subdivision of the palaeocene part of the gran sasso d’italy succession (central appennines) by thin section is nearly as precise as with isolated specimens. palaeocene planktonic foraminiferal identification is based on van konijnenburg et al. (1998), berggren et al. (1995), olsson et al. (1999) and olsson et al. (2011). biozonation of berggren et al. (1995), olsson et al. (1999), berggren & pearson (2005) and olsson et al. (2011) adjusted to an updated timescale (vandenberghe et al., 2012; anthonissen & ogg, 2012) is followed herein. because two dimensional axial views of some palaeocene species in thin section can have a similar appearance, separation of these taxa is not always possible. therefore, these species are grouped together such as the morozovella angulata – morozovella aequa group and morozovella conicotruncana – morozovella velascoensis group as in sari (2013). the other keeled late palaeocene taxa such as globanomalina planoco­ nica, globanomalina pseudomenardii, igorina albeari, moro­ zovella acuta, morozovella acutispira, morozovella occlusa, mo­ rozovella pasionensis and acarinina subsphaerica can be determined in thin section as their typical characteristics are seen in axial sections. thin sections were studied under an olympus bx50 microscope and photomicrographs were taken by an olympus e330 camera attached to the microscope. all the specimens and thin sections described and illustrated in this paper are stored in the department of geological engineering of dokuz eylül university. 3. geological setting and stratigraphy the nappe piles in sw turkey, which were named as lycian nappes by brunn et al. (1971) have been known since philipson’s work (1915). the lycian nappes comprise ophiolites and several tectono-stratigraphic units, which represent various environmental conditions (i.e. platform, slope and basin etc.) and were thrust on top of the para-autochthonous bey dağları and menderes successions (de graciansky, 1972; özgül, 1976; poisson, 1977; gutnic et al., 1979; şengör & yilmaz, 1981; şenel, 1991; 1997a, b, 2007; collins & robertson, 1998; pourteau et al., 2016). the lycian nappes were divided into five nappe packages by şenel (1997a, b); the tavas, bodrum, gülbahar, domuzdağ, and marmaris ophiolite nappes in structurally ascending order (figs. 1c, 2). they were mainly amalgamated as a result of three main successive tectonic phases including i) obduction of the lycian ophiolites on top of the campanian–maastrichtian mélange and the köyceğiz nappe, ii) thrusting on top of the lower eocene fore-deep, and iii) thrusting on top of the lower miocene fore-deep (i.e. de graciansky, 1972; gutnic et al., 1979; collins & robertson, 1998; pourteau et al., 2016). various names were attributed to the lycian nappe packages by different research groups and individual researchers through the years (see references in table 1 for correlation). different names ascribed to the tavas nappe of şenel et al. (1994) are briefly compiled in table 1. the tavas nappe, the lowermost tectonostratigraphic unit of the lycian nappes is divided into the karadağ, tekedere and haticeana serie (fig. 2a) (de graciansky, 1972; şenel, 1997a, b). the lowermost karadağ unit consists of a gondwana type neotethyan platform succession ranging from the upper devonian to the upper triassic. the upper carboniferous–middle permian tekedere succession is composed of several thrust sheets of palaeotethyan origin (moix et al., 2013). the haticeana serie unconformably overlies the karadağ and tekedere serie and comg eo lo gi a c ro at ic a geologia croatica 70/3166 prises from bottom to top, rhaetian–lower liassic continental clastics (çenger fm.), liassic platform limestones (ağaçlı fm.), toarcian–maastrichtian cherty micritic limestones and calciturbidites (babadağ fm.) and palaeocene–lutetian (middle eocene) micritic limestones, basic volcanics and clastics (faralya fm.) (fig. 2b) (şenel, 1997a, b; soycan et al., 2015). lithostratigraphic details of the upper parts of the babadağ fm. and the lowermost part of the faralya fm. observed on the bozburun hill locality are presented below. 3.1. the babadağ formation the babadağ fm. named by erakman et al. (1982) rests on the ağaçlı fm. along a local unconformity surface and comprises a 650–1020 m thick limestone dominated succession (şenel, 1997a). the unit locally includes toarcian ‘ammonitico rosso facies’ at the base and is mainly represented by cherty micritic limestones and calciturbidites. the limestone succession includes local lenses of radiolarites, cherts and shales several metres thick, comprising rudist shells and fragments at the top (şenel, 1997a; gül, 2015). sedimentological and petrographic characteristics and controlling factors of silicification and types of cherts of the bozburun hill locality were recently documented by gül (2015). approximately 80 m of the uppermost part of the babadağ fm., made up of four lithostratigraphic levels, was examined in this study (fig. 3). the succession has well-preserved outcrops at the top of bozburun hill and by the roadcut to the top of the hill (fig. 1c). the succession is dominated by light grey, whitish grey, grey, locally dark grey-coloured, medium to thick, locally thinbedded planktonic foraminifera-bearing micritic limestones (fig. 3, pl. 1). calciclastic (or calciturbidite) beds (calcirudites, calcarenites and calcilutites) are intercalated with the micritic limestones. the 8 m thick base of the section comprises chert bands and lenses and shows widespread bioturbation (level–1). the overlying 22 m (level–2) is represented by the alternation of micritic limestones and calcarenites, which include rare coarse lithoclasts and bioclasts (i.e. rudists and corals). level–3 is made up of 15 m of distinctly-bedded micritic limestones with thin siltstone interlayers and chert lenses and bands (pl. 1a). the thickness of the chert bands and lenses ranges between 0.5 to 2.5 m, and they are 0.2 to 3–4 m long. an approximately 35 m thick level–4 at the top of the section is represented by the dominance of thick calciclastic beds (mainly calcarenites and calcirudites) (0.5 to 1 m thick), which are intercalated with thin micritic limestone beds (0.2 to 0.3 m thick). calciclastic beds include abundant limestone lithoclasts, rudist shell fragments, benthic foraminifera (orbitoidae) and rare gastropods (pl. 1b, c). some of the rudist shells are complete or have well-preserved transverse sections (pl. 1c). a rudist association comprising hippurites cornucopiae, biradiolites aff. cha­ figure 2. a) a stratigraphic column of the tavas nappe (simplified after şenel, 1997a). studied sections correspond to the uppermost part of the babadağ formation and the lowermost part of the faralya formation (age of the tekedere and karadağ series is adapted from moix et al., 2013), b) tectonostratigraphic positions of the nappe piles of the lycian nappes over the relatively autochthonous units. the tavas nappe lies at the base of these nappe packages (simplified after şenel, 1997a). g eologia c roatica sarı bilal: lithostratigraphy and planktonic foraminifera of the uppermost cretaceous–upper palaeocene strata of the tavas ... 167 peri, bournonia cf. fascicularis, b. cf. triangulata, biradiolites sp., lapeirousia sp. and durania sp. was previouly determined in this level (özer et al., 2015; özer et al., 2017). h. cornucopiae within the association is known as a late maastrichtian taxa for the mediterranean province (özer et al., 2015; özer et al., 2017). a few large limestone lithoclast-rich interlayers are also observed within this level (pl. 1d). some levels comprise several limestone lithoclasts, many of which are planktonic foraminifera-bearing pelagic lithoclasts (pl. 1e). these lithoclasts have sinuous boundaries with the calciclastic facies, in which they are embedded. this indicates that the two facies (i.e. planktonic foraminifera-bearing micritic facies and calciclastic facies) were both soft and not lithified during transportation. a 1 m thick calciclastic bed (laminated calcarenites) in the middle of this level shows low-angle cross-lamination (pl. 1f). this bed is mainly made up of millimetreto centimetre-sized intraclasts and skeletal debris consisting mainly of rudist fragments. this type of calciclastic beds are interpreted as proximal storm deposits (tempestites) in the literature (aigner, 1985; wright, 1986; flügel, 2004). in thin section, the micritic limestones are represented by planktonic foraminifera-bearing wackestone depositional textures, which correspond to a background sedimentation in this type of calciturbidite deposits (pl. 2a–c) (flügel, 2004). planktonic foraminifera and other fine clasts show parallel lamination in some beds (pl. 2b), formed as a result of transportation. calciclastic beds are mainly represented by litho-bioclastic rudstone/ grainstone depositional textures, which are commonly associated with planktonic foraminifera (globigerinidae)-bearing wackestones/mudstones. carbonate lithoclasts showing various depositional textures were derived mainly from shallow water (i.e. carbonate mudstone with benthic foraminifera belonging to the family miliolidae) and slope environments (i.e. rudstone with rudist fragments and benthic foraminifera belonging to family orbitoidae). planktonic foraminifera-bearing pelagic lithoclasts are also observed. some of the lithoclasts are recrystallized. bioclasts are mainly represented by benthic foraminifera (chiefly orbitoidae) and rudist shell fragments (pl. 2d, e). these types of facies correspond to the allochthonous parts of the calciturbidite deposits (flügel, 2004). the irregular and sinuous nature of the boundary between the allochthonous rudstone/grainstone facies and the planktonic foraminifera-bearing wackestone facies suggests that the two facies were not lithified but were soft during transportation. similar calciclastic deposits were documented from the upper campanian of the eastern pontides by sofracioğlu & kandemir (2013) and sari et al. (2014). this type of calciclastic deposits (i.e. calciturbidites) (braunstein, 1961) is typically deposited both on the slope and on the deeper sea floor at the base of the slope to basin transition (meischner, 1964; mcilreath & james, 1984). silt to figure 3. a stratigraphic column of the babadağ formation with the distribution of planktonic foraminifera in section–1 (coordinates; base: 35 s 0646207/4070449, top: 35 s 0646052/4070553). see figure 2. for explanation of symbols. g eo lo gi a c ro at ic a geologia croatica 70/3168 boulder size carbonate particles were derived from the shallowwater platform margin, where benthic organisms such as foraminifera (mainly orbitoidae), rudists, corals and algae flourished. these deposits are transported down the slope by submarine debris-flows or other mass-transport mechanisms (mcilreath & james, 1984; payros & pujalte, 2008). the presence of reworked benthic organisms within the succession deposited in a deeper environment indicates that a carbonate platform persisted on a more marginal part of the late campanian–maastrichtian basin. 3.2. faralya formation the formation is composed of various ‘flysch–like’ lithologies (i.e. micritic limestones, sandstones, breccia etc.) and basic volcanics and was named by şenel et al. (1989). the lithostratigraphic characteristics and the lateral and vertical facies changes of the faralya fm. were documented in 12 stratigraphic sections by şenel (1991). eight of the sections were measured se of çameli (ne of fethiye), three measured around babadağ (se of fethiye) and one measured from the n of kalkan (fig. 1). according to the author, the unit ranges from the late palaeocene to lutetian (middle eocene) in age, disconformably overlies the babadağ fm. (fig. 2a) and is tectonically overlain by the bodrum nappe (şenel, 1991; 1997a, b). the thickness of the formation reaches a maximum 290 m (şenel, 1997b). the formation consists of micritic limestones and clayey limestones (or sandy limestones and calcarenites) with local chert lenses at the base in the ne and se of fethiye. towards the top, the formation includes basic volcanics, limestones, breccia with chert clasts, calciturbidites, sandstones, claystones, conglomerates etc., which interfinger with each other (şenel, 1991; şenel, 1997a, b). details of the lithostratigraphy of the faralya fm. in the bozburun hill locality have not been previously documented. the patchy outcrops of the faralya fm. are observed on the eastern slope of bozburun hill. lithological characteristics and planktonic foraminiferal assemblages of the formation were documented by two stratigraphic sections (figs. 1c, 4) as a composite section representing the whole formation could not be found in this locality due to the tectonically disturbed geology of the area. the succession can be divided into four different lithostratigraphic levels in section–2 (fig. 4). the 1.5 m thick lowermost part of the section (level–1) is made up of grey-coloured medium to thick-bedded bioclastic/lithoclastic limestones, which includes planktonic foraminifera-bearing thin pelagic micritic limestone interbeds. bioclastic/lithoclastic levels (i.e. the lowermost bed, where sample 15–17 was taken) comprise several limestone lithoclasts and bioclasts derived from the upper cretaceous. this level is overlain by 3 m of pinkish grey-coloured planktonic foraminifera-bearing laminated micritic limestones with rare chert bands (level–2). level–3 comprises an approximately 1 m thick sequence of reddish grey-pale red-coloured calcareous mudstones, with very rare planktonic foraminifera. the overlying level–4 is represented by mudstone-siltstone alternations with limestone blocks. this part of the section does not yield planktonic foraminifera (fig. 4). diverse lithoclasts and bioclasts are observed within the grainstone/packstone texture of the level–1 (samples 15–17, 15– 25) (fig. 4). many of the abundant bioclasts were derived from the uppermost cretaceous (i.e. benthic foraminifera belonging to the family orbitoidae and miliolidae, algae, corals and bryozoa). some lithoclasts include campanian–maastrichtian planktonic foraminifera and other litho-bioclasts are embedded within the rare palaeocene planktonic foraminifera-bearing micrite matrix. the bed, from which sample 15–24 was taken is a thin interlayer within the litho-bioclastic limestones and comprises planktonic foraminifera-bearing wackestones, which is represented by rare but index keeled late palaeocene taxa. limestones in level–2 are dominated by planktonic foraminifera-bearing wackestone depositional textures (fig. 4, pl. 2f), where several late palaeocene taxa were identified. the second stratigraphic section (section–3) from the faralya fm. was measured some 2 km east of the summit of bozburun hill along the bozburun hill–dalyan roadcut (figs. 1c, 5). a 12 m thick part of the formation is observed in this locality, which is made up of an alternation of micritic limestones and brecciated limestones. micritic limestone levels are represented by planktonic foraminifera-bearing wackestone depositional textures. intercalating brecciated limestone beds show similar depositional textures with the base of the section–2 (level–1). the limestone clasts suggesting various depositional settings (i.e. platform, slope and basin) are embedded within the planktonic foraminifera (palaeocene taxa)–bearing micritic matrix. transported benthic organisms such as the latest cretaceous foraminifera (orbitoidae), rudist fragments, algae and corals are also observed within the matrix. the angular clasts are larger in section–3 when compared to section–2 and ranges up to 15 cm with an average of some 7–8 cm. these data indicate that deep marine calciclastic deposition occurred during the latest cretaceous and prevailed in the late palaeocene after a sedimentary break corresponding to the early palaeocene. figure 4. a stratigraphic column of the faralya formation with the distribution of planktonic foraminifera in section–2 (coordinate; 35 s 0646439/4070628). see figure 2. for explanation of symbols. g eologia c roatica sarı bilal: lithostratigraphy and planktonic foraminifera of the uppermost cretaceous–upper palaeocene strata of the tavas ... 169 3.3. boundary between the babadağ and faralya formations the boundary between the babadağ and faralya formations was reported as a disconformity by şenel (1991) to the ne and se of fethiye. the boundary between the two formations is observed in a locality, where section–2 was measured, some 800 m east of the summit of bozburun hill (fig. 1c). the babadağ fm. in this locality is represented by grey-coloured, well-bedded limestones with chert bands and angular lithoclasts. the limestones are overlain by pinkish grey-coloured friable laminated clayey limestones. the succession is cut by faults to the west and east (fig. 6). cherty limestones of the babadağ fm. are represented by rare planktonic foraminifera-bearing wackestones with angular recrystallized intraclasts in thin section. sample 15–16 is barren, while sample 15–15 comprises a few campanian–maastrichtian double-keeled globotruncanids. the assemblage includes glo­ botruncana cf. bulloides, g. linneiana and g. mariei, but does not yield index taxa. in the absence of any characteristic taxa, occurrences of g. cf. bulloides and g. linneiana in the uppermost beds of the babadağ fm. in that section show that at least the uppermost maastrichtian is absent in this locality as both taxa make their last occurrences within the lower part of the abathompha­ lus mayaroensis zone (fig. 7). the overlying laminated micritic limestones are represented by wackestones with mainly globular/ semiglobular-chambered and a few keeled palaeocene morphotypes (sample 15–18). two such identified taxa are morozovella occlusa and acarinina subsphaerica suggesting that the age of the lowermost layers of the faralya fm. is late palaeocene (selandian–thanetian) in the bozburun hill locality as both taxa first appear within the p4a zone (around middle part of selandian) (fig 7). therefore, the boundary is disconformable in this locality and the time gap between the two formations corresponds to the latest maastrichtian to the earliest selandian. 4. planktonic foraminiferal assemblages of the studied sections 4.1. section–1 micritic limestones of the babadağ fm. comprise quite diverse planktonic foraminiferal assemblages, while calciclastic beds include limited amount of taxa (fig. 3). the planktonic foraminiferal assemblages are mainly represented by double and single keeled globotruncanids, which are associated with rare rugoglobigerinids and multiserial heterohelicids. the following taxa were observed through section–1; abathomphalus mayaroensis, con­ tusotruncana fornicata, c. cf. plummerae, c. walfischensis, gansserina gansseri, globotruncana cf. aegyptiaca, g. arca, g. arca­orientalis, g. bulloides, g. dupeublei, g. esnehensis, g. cf. falsostuarti, g. hilli, g. linneiana, g. mariei, g. neotricarinata, g. orientalis, g. ventricosa, globotruncanella havanensis, gl. petaloidea, globotruncanita conica, gt. pettersi, gt. stuarti, gt. stuartiformis, gublerina sp., racemiguembelina fructicosa, ra­ dotruncana subspinosa, rugoglobigerina pennyi and r. rugosa (fig. 3, pl. 3). many of the taxa identified above are classically observed within the tethyan campanian–maastrichtian deposits (see papers in introduction part). the presence of r. fructicosa and a. mayaroensis within the assemblages is important as they are the nominated taxa of the r. fructicosa and a. mayaroensis zones of the late maastrichtian (figs. 3, 7) (e.g. premoli silva & verga, 2004; gradstein et al., 2012; coccioni & premoli silva, 2015). both taxa were rarely observed in the uppermost part of the babadağ fm., where sample 15–06 and sample 15–04 include single specimens of r. fructicosa and a. mayaroensis respectively (fig. 3). the absence of g. bulloides and g. linneiana in sample 15–04 may indicate that the 10 m thick uppermost part of the succession corresponds to the upper part of the a. mayaroensis zone, or may be younger as these two taxa make their last appearance within the lower part of the a. mayaroensis zone (figs. 3, 7). the occurrence of ga. gansseri in sample 15–11 indicates that the age of this level and the limestones above should not be older than the latest campanian, while the age of the lowermost part of the succession may be late campanian. however, this part should not be older than the gl. ha­ vanensis zone as the nominated taxon of the ra. calcarata zone, ra. calcarata was not observed in any samples at the base of the babadağ succession (figs. 3, 7). 4.2. section–2 the lower part of section–2 (level–1) includes rare planktonic foraminifera as this part is made up of mainly calciclastic limestones (fig. 4). level–2 is represented by its relatively rich planktonic foraminifera content with the following taxa observed within the limestones; globanomalina pseudomenardii, igorina albeari, morozovella acuta, gr. m. angulata – m. aequa, gr. cf. m. conicotruncana – m. velascoensis, m. occlusa and m. prae­ angulata– angulata (fig. 4, pl. 4). the occurrence of m. acuta in sample 15–24 suggests that the age of the lowermost part of the section is not older than the thanetian, as the species makes its first appearance by the selandian–thanetian boundary (figs. 4, 7). other taxa such as g. pseudomenardii and i. albeari are restricted to the selandian–thanetian. m. occlusa makes its first figure 5. a stratigraphic column of the faralya formation with the distribution of planktonic foraminifera in section–3 (coordinate: 35 s 0647417/4070469). see figure 2. for explanation of symbols. g eo lo gi a c ro at ic a geologia croatica 70/3170 appearance at the base of the p4a zone (middle selandian) (berggren et al., 1995; olsson et al., 1999; anthonissen & ogg, 2012) (figs. 4, 7). 4.3. section–3 micritic limestone interlayers of section–3 yield planktonic foraminiferal assemblages, which are dominated by keeled late palaeocene morphotypes (fig. 5, pl. 5). the micritic matrix of the brecciated limestones contains rare planktonic foraminifera. the assemblages comprise g. planoconica, g. pseudomenardii, i. albeari, m. acuta, m. acutispira, gr. m. angulata–m. aequa, gr. m. conicotruncana–m. velascoensis, m. occlusa and m. pa­ sionensis (fig. 5, pl. 5). the occurrence of m. cf. acuta in sample 15–30 suggests that the age of the lowermost part of the section is not older than the thanetian as in section–2. likewise, the presence of g. planoconica in sample 15–34 shows that the age of the upper part of the section is late thanetian as the species makes its first appearance within the p4c zone (berggren et al., 1995; olsson et al., 1999; anthonissen & ogg, 2012) (figs. 5, 7). the planktonic foraminiferal assemblages observed in two sections show that the successions are more or less time equivalent. therefore, lithological differences between them (i.e. the absence of brecciated limestones in section–2) could be the result of lateral facies changes within the basin. acarinina subsphaerica and m. occlusa are observed in the lowermost limestone beds of the faralya fm. (fig. 6, sample 15– 18). both taxa make their first appearances close to the base of zone p4a and m. occlusa disappears before the end of zone p4b (berggren et al., 1995; olsson et al., 1999; anthonissen & ogg, 2012) (fig. 7). therefore the age of the lowermost layers of the faralya fm. is late palaeocene (middle selandian– middle thanetian) at the bozburun hill locality (figs. 6, 7). alternatively, taking into account the fact that the planktonic foraminiferal assemblages of both sections of the faralya fm. indicate a clear thanetian age, the age of the lowermost beds of the formation is also thanetian, but indicators of the thanetian (i.e. m. acuta, g. planoconica etc.) were somehow not observed in the sample. in this case, the danian and selandian (corresponding to some 7 ma duration of time), are missing at the bozburun hill locality. 5. discussion and conclusions lithostratigraphic characteristics and planktonic foraminiferal assemblages of the upper part of the babadağ fm. and the lower part of the faralya fm. have been documented for the first time by three stratigraphic sections from the bozburun hill locality of the tavas nappe of the lycian nappes. the upper parts of the babadağ fm. are mainly represented by cherty micritic and calciclastic limestones. micritic limestone beds comprise diverse planktonic foraminiferal assemblages yielding a late campanian–maastrichtian age. a late maastrichtian age is obtained from the uppermost layers of the babadağ fm., based on the presence of r. fructicosa and a. mayaroensis. an abundance of keeled globotruncanids (k–selection) within the assemblages indicates a relatively deep pelagic environment as these large, thick–walled, complex morhotypes dominate in open oceans, mainly during the onset of high sea level stands (caron & homewood, 1983; robaszynsi & caron, 1995; abramovich et al., 2010). figure 6. cretaceous/palaeocene boundary section, observed as a thin sequence package between two faults (coordinates: 35 s 0646439/4070628). the boundary includes a gap ranging from the latest maastrichtian to the earliest selandian. figure 7. latest cretaceous–palaeocene planktonic foraminiferal biozones and bioevents of some selected stratigraphically important taxa (first and last appearance datums) observed in this study. numerical ages, biozones and the first and last appearance datums of the selected taxa are adapted from ogg & hinnow (2012) and anthonissen & ogg (2012) (for the upper cretaceous) and vandenberghe et al. (2012) and anthonissen & ogg (2012) (for the palaeocene). g eologia c roatica sarı bilal: lithostratigraphy and planktonic foraminifera of the uppermost cretaceous–upper palaeocene strata of the tavas ... 171 the faralya fm. is studied in two sections, which have different lithological properties but similar planktonic foraminiferal assemblages and ages. section–2 is mainly made up of planktonic foraminifera–bearing wackestones with calciclastic beds at the base and mudstones with limestone blocks at the top. section–3 is represented by the alternation of planktonic foraminifera-bearing wackestones and brecciated limestones. planktonic foraminiferal assemblages of the two sections are dominated by keeled late palaeocene morphotypes. occurrence of m. acuta at the base of section–2 suggests that the age of the lowermost part of the section is not older that the thanetian. likewise, the presence of m. cf. acuta and g. planoconica at the base and top of section–3 respectively shows that the age of the lowermost part of the section is not older that the thanetian as in section–2 and the age of the upper part is late thanetian (zones p4c or p5). a unique section including the disconformable boundary of the babadağ and faralya formations at the bozburun hill locality shows that the latest maastrichtian to earliest selandian rocks are absent. a gap of similar duration between two formations was also reported to the north and east of the study area (n and e of fethiye) by şenel (1991). the latest cretaceous–early palaeocene unconformity in the tavas nappe was linked with the first of the three main tectonic events, when trench-passive margin collision caused ophiolite obduction and the köyceğiz thrust sheet was incorporated into the lycian allochthon (collins & robertson, 1998). during that time interval, the upper levels of the lycian allochthon were subaerially exposed. the presence of eroded cretaceous carbonates and foraminifera observed within the thanetian calciclastic rocks as lithoclasts or bioclasts could be clues to that exposure and erosion (i.e. the base of the section–2) (fig. 4). acknowledgement this work was financially supported by a tubi̇tak grant (project no: 113y144), which is acknowledged. i would like to thank sacit özer and talip güngör for participating in the field studies and providing suggestions on the manuscript. two anonymous reviewers and the associated editor vlasta ćosović are thanked for their constructive criticisms of the manuscript. references abramovich, s., yovel-corem, s., almogi-labin, a. & benjamini, c. (2010): global climate change and planktic foraminiferal response in the maastrichtian.– paleoceanography, 25, pa2201. doi: 10.1029/2009pa001843 aigner, t. (1985): storm depositional systems.– lecture notes in earth science, 3, 174 p., stuttgart (schweizerbart). anthonissen, d.e. & ogg, j.g. (compilers) (2012): appendix 3: cenozoic and cretaceous biochronology of planktonic foraminifera and calcareous nannofossils.– in: gradstein, f.m., ogg, j.g., schmitz, m.d. & ogg, g.m. (eds.): the geologic time scale 2012, volume 2. amsterdam, the netherlands: elsevier, 1083–1127. arslan, a., güngör, t., erdoğan, b. & passchier, c.w. (2013): tectonic transport directions of the lycian nappes in southwest turkey constrained by kinematic indicators.– journal of asian earth sciences, 64, 198–209. doi: 10.1016/j. jseaes.2012.12.016 berggren, w.a. & pearson, p.n. (2005): a revised tropical to subtropical palaeogene planktonic foraminiferal zonation.– journal of foraminiferal research, 35, 279–298. berggren, w.a., kent, d.v., swisher, c.c. iii & aubry, m.p. (1995): a revised cenozoic geochronology and chronostratigraphy.– in: berggren, w.a., kent, d.v., swisher, c.c., iii, aubry, m.p. & hardenbol, j. (eds.): geochronology, time scales and global stratigraphic correlation. society for sedimentary geology, special publication, 54, 129–212. doi: 10.2110/ pec.95.04.0129 braunstein, j. (1961): calciclastic and siliciclastic.– american association of petroleum geologists bulletin, 45, 2017. brunn, j.h., dumont, j.f., de graciansky, p.c., gutnic, m., juteau, t., marcoux, j., monod, o. & poisson, a. (1971): outline of the geology of the western taurides.– in: campbell, a.s. (ed.): geology and history of turkey. petroleum exploration society of libya: tripoli, libya, 225–255. caron, m. (1985): cretaceous planktic foraminifera.– in: bolli, h.m., saunders, j.b. & perch-nielsen, k. (eds.): plankton stratigraphy. cambridge university press, cambridge, 17–86. caron, m. & homewood, p. (1983): evolution of early planktic foraminifers.– marine micropaleontology, 7, 453–462. doi: 10.1016/0377-8398(83)90010-5 coccioni, r. & premoli silva, i. (2015): revised upper albian–maastrichtian planktonic foraminiferal biostratigraphy and magnetostratigraphy of the classical tethyan gubbio section (italy).– newsletter on stratigraphy, 48/1, 47–90. collins, a.s. & robertson, a.h.f. (1997): lycian mélange, southwestern turkey: an emplaced late cretaceous accretionary complex.– geology, 25, 255–258. collins, a.s. & robertson, a.h.f. (1998): processes of late cretaceous to late miocene episodic thrust–sheet translation in the lycian taurides, sw turkey.– journal of the geological society london, 155, 759–772. collins, a.s. & robertson, a.h.f. (1999): evolution of the lycian allochthonous, western turkey, as a north–facing late palaeozoic to mesozoic rift and passive continental margin.– geological journal, 34, 107–138. collins, a.s. & robertson, a.h.f. (2003): kinematic evidence for late mesozoic–mioecene emplacement of the lycian allochthonous over the western anatolide belt, sw turkey.– geological journal, 38, 295–310. erakman, b., meşhur, m., gül, m.a., alkan, h., öztaş, y. & akpinar, m. (1982): fethiye–köyceğiz–tefenni–elmalı–kalkan arasında kalan alanın jeolojisi [geology of the area between fethiye–köyceğiz–tefenni–elmalı–kalkan –in turkish]: 6th petroleum congress of turkey, ankara, 23–31. flügel, e. (2004): microfacies of carbonate rocks. analysis, interpretation and application.– springer, berlin, heidelberg, new york, 976 p. göncüoğlu, m.c. (2011): geology of the kütahya–bolkardağ belt.– mta bulletin, 142, 223–277. görür, n. & tüysüz, o. (2001): cretaceous to miocene palaeogeographic evolution of turkey: implications for hydrocarbon potential.– journal of petroleum geology, 24, 1–28. doi: 10.1111/j.1747-5457.2001.tb00664.x graciansky de, p. c. (1968): stratigraphie des unités superposées dans le taurus lycien et place dans l’arc dinaro–taurique.– mineral research and exploration bulletin, 71, 42–62. graciansky de, p. c. (1972): recherches géologiques dans le taurus lycien occidental.– thèse doctorat d’etat, université de paris–sud, orsay, france, 762 p. gradstein, f.m., ogg, j.g., schmitz, m.d. & ogg, g.m. (eds.) (2012): the geologic time scale 2012. elsevier, 1.144 p. gutnic, m., monod, o., poisson, a. & dumont, j.f. (1979): géologie des taurides occidentales (turquie).– mémoires de la société géologique de france, 137, 1–112. gül, m. (2015): occurrences of chert in jurassic–cretaceous calciturbidites (sw turkey).– central european journal of geosciences, open geosciences (scie), 7, 446–464. huber, b.t., macleod, k.g. & tur, n.a. (2008): chronostratigraphic framework for late campanian–maastrichtian sediments on blake nose (subtropical north atlantic).– journal of foraminiferal research, 38, 162–182. konak, n., akdeniz, n. & öztürk, e.m. (1987). geology of the south of menderes massif. igcp project no: 5, correlation of variscan and pre-variscan events of the alpine mediterranean mountain belt, field meeting: mineral research and exploration bulletin, 42–53. li, l. & keller, g. (1998a): maastrichtian climate, productivity and faunal turnovers in planktic foraminifera in south atlantic dsdp sites 525a and 521.– marine micropaleontology, 33, 55–86. li, l. & keller, g. (1998b): diversification and extinction in campanian–maastrichtian planktic foraminifera of northwestern tunisia.– eclogae geologicae helvetiae, 91, 75–102. mcilreath, i.a. & james, n.p. (1984): carbonate slopes.– in: walker, r.g. (ed.): facies models, 2nd ed. geoscience canada reprint ser., 1, 245–257. meischner, k.d. (1964): allodapische kalke, turbidite in riff–nahen sedimentationsbecken.– in: bouma, a.h. & brouwer, a. (eds.): developments in sedi-in: bouma, a.h. & brouwer, a. (eds.): developments in sedimentology, vol. 3. elsevier, amsterdam, 156–191. moix, p., vachard, d., allibon, j., martini, r., wernli, r., kozur, h.w. & stampfli, g.m. (2013): palaeotethyan, neotethyan and huğlu–pindos series in the lycian nappes (sw turkey): geodynamical implications.– in: tanner, l.h., spielmann, j.a. & lucas, s.g. (eds.): the triassic system. new mexico museum of natural history and science bulletin, 61, 401–444. ogg, j.g. & hinnov, l.a. (2012): cretaceous.– in: gradstein, f.m., ogg, j.g., schmitz, m.d. & ogg, g.m. (eds.): the geologic time scale 2012, volume 2. amsterdam, the netherlands: elsevier, 793–854. doi: 10.1016/b978-0-44459425-9.00027-5 g eo lo gi a c ro at ic a geologia croatica 70/3172 plate i field views of the calciclastic limestones of the babadağ formation along section–1. a) micritic limestones with a thin chert band (c) an allochthonous calcarenite bed (a), b) alternation of planktonic foraminifera-rich micritic limestone layers (l: light layers) and allochthonous lithobioclasts–rich calcarenite/calcirudite layers (d: dark layers), c) close-up view of a calcarenite/calcirudite bed, which is mainly composed of neritic bioclasts and lithoclasts. complete rudist shells (r) are also seen in these layers, d) close up view of a lithoclastic bed, which comprises neritic and pelagic carbonate lithoclasts (arrows) embedded within the planktonic foraminifera-bearing micritic matrix, e) a thick calciclastic bed including neritic and pelagic lithoclasts; almost all the pelagic lithoclasts (pl) have a sinuous boundary (sb) with the calciclastic facies (cf), f) a thick calciclastic bed showing cross-bedding. g eologia c roatica sarı bilal: lithostratigraphy and planktonic foraminifera of the uppermost cretaceous–upper palaeocene strata of the tavas ... 173 plate ii photomicrographs of several facies of the calciclastic and micritic limestones in the babadağ and faralya formations. a) planktonic foraminifera-rich wackestone, which is the dominant facies in the babadağ formation (sample 15–06), b) wackestone with planktonic foraminifera, showing a parallel orientation (sample 15–09), c) wackestone with planktonic foraminifera and fine recrystallized bioclasts (sample 15–11), d) the contact between the wackestone/lime mudstone with rare planktonic foraminifera (pf) and the litho-bioclastic rudstone/grainstone with benthic foraminifera belonging to family orbitoidae (obf). note the irregular and sinuous nature of the boundary (sample 15–02), e) litho-bioclastic rudstone/grainstone with angular lithoclasts (l) and benthic foraminifera (orbitoidae) (obf) (sample 15–13), f) wackestone with planktonic foraminifera (sample 15–20), which is the typical depositional texture of the micritic limestones of the faralya formation. planktonic foraminifera are dominated by keeled late palaeocene morphotypes. g eo lo gi a c ro at ic a geologia croatica 70/3174 a) abathomphalus mayaroensis, sample 15–05, b) contusotruncana fornicata, sample 15–09, c) contusotruncana walfischensis, sample 15–03, d) gansserina gansseri, sample 15–11, e) gansserina gansseri, sample 15–06b, f) globotruncana aegyptiaca, sample 15–09, g) globotruncana arca, sample 15–06b, h) globotruncana arca, sample 15–02, i) globotruncana arca, sample 15–09, j) globotruncana arca, sample 15–08, k) globotruncana arca-orientalis, sample 15–08, l) globotruncana bulloides, sample 15–12, m) globotruncana dupeublei, sample 15–06a, n) globotruncana esnehensis, sample 15–06a, plate iii thin section photomicrographs of the planktonic foraminifera observed in the upper part of the babadağ formation along the section–1. o) globotruncana esnehensis, sample 15–06a, p) globotruncana esnehensis, sample 15–06b, r) globotruncana hilli, sample 15–08, s) globotruncana hilli, sample 15–11, t) globotruncana linneiana, sample 15–08, u) globotruncana linneiana, sample 15–11, v) globotruncana linneiana, sample 15–15, y) globotruncana cf. mariei, sample 15–11, z) globotruncana neotricarinata, sample 15–12, a1) globotruncana neotricarinata, sample 15–09, b1) globotruncana cf. orientalis, sample 15–08, c1) globotruncana ventricosa, sample 15–12, d1) globotruncana ventricosa, sample 15–06b, e1) globotruncana ventricosa, sample 15–06b, f1) globotruncanella havanensis, sample 15–08, g1) globotruncanella havanensis, sample 15–02, h1) globotruncanella petaloidea, sample 15–12, i1) globotruncanita conica, sample 15–09, j1) globotruncanita pettersi, sample 15–09, k1) globotruncanita stuarti, sample 15–06b, l1) globotruncanita stuartiformis, sample 15–06b, m1) racemiguembelina fructicosa, sample 15–06a, n1) rugoglobigerina pennyi, sample 15–03, o1) rugoglobigerina pennyi, sample 15–08, p1) rugoglobigerina pennyi, sample 15–17, r1) rugoglobigerina rugosa, sample 15–08, s1) rugoglobigerina rugosa, sample 15–11. g eologia c roatica sarı bilal: lithostratigraphy and planktonic foraminifera of the uppermost cretaceous–upper palaeocene strata of the tavas ... 175 plate iv. thin section photomicrographs of the planktonic foraminifera observed in the lower part of the faralya formation along section–2. the planktonic foraminiferal assemblages are mainly represented by keeled late palaeocene morphotypes. a) acarinina subsphaerica, sample 15–18, b) igorina albeari, sample 15–20, c) igorina albeari, sample 15–21, d) igorina albeari, sample 15–21, e) igorina albeari, sample 15–21, f) igorina albeari, sample 15–23, g) morozovella cf. acuta, sample 15–21, h) morozovella cf. acuta, sample 15–20, i) morozovella aequa, sample 15–19, j) morozovella aequa, sample 15–19, k) morozovella occlusa, sample 15–22, l) morozovella occlusa, sample 15–18, m) morozovella occlusa, sample 15–19, n) morozovella occlusa, sample 15–19, o) morozovella occlusa, sample 15–22. g eo lo gi a c ro at ic a geologia croatica 70/3176 plate v. thin section photomicrographs of the planktonic foraminifera observed in the lower part of the the faralya formation along section–3. the planktonic foraminiferal assemblages are mainly represented by keeled late palaeocene morphotypes as in section–2. a) globanomalina planoconica, sample 15–34, b) globanomalina planoconica, sample 15–34, c) globanomalina pseudomenardii, sample 15–36, d) globanomalina pseudomenardii, sample 15–36, e) globanomalina pseudomenardii, sample 15–36, f) igorina albeari, sample 15–36, g) igorina albeari, sample 15–34, h) morozovella cf. acuta, sample 15–30, i) morozovella acutispira, sample 15–31, j) morozovella acutispira, sample 15–36, k) morozovella conicotruncana, sample 15–34, l) morozovella occlusa, sample 15–36, m) morozovella pasionensis, sample 15–36. g eologia c roatica sarı bilal: lithostratigraphy and planktonic foraminifera of the uppermost cretaceous–upper palaeocene strata of the tavas ... 177 okay, a.i̇. (1989): geology of the menderes massif and the lycian nappes south of denizli, western taurides.– mineral research and exploration bulletin, 109, 37–51. okay, a.i. & tüysüz, o. (1999): tethyan sutures of northern turkey.– in: durand, b., jolivet, l., horvath, f. & seranne, m. (eds.): the mediterranean basins: tertiary extension within the alpine oregen. geological society special publication, 156, 475–515. doi: 10.1144/gsl.sp.1999.156.01.22 olsson, r.k., hemleben, c., berggren, w.a. & huber, b.t. (1999): atlas of palaeocene planktonic foraminifera.– smithsonian contributions to paleobiology, 85, 1–252. olsson, r.k., hemleben, c., berggren, w.a. & huber, b.t. (2011): atlas of palaeocene planktonic foraminifera. http://services.chronos.org/foramatlas/pages/home.htm. özer, s., güngör, t., sari, b., sagular, e.k., özkar-öngen, i̇. & görmüş, m. (2015): stratigraphy of the metamorphic tectonic units of the lycian nappes based on palaeontological data (rudist, foraminifera, nannoplankton), kinematic characteristics and comparison with the menderes massif and afyon zone. tübi̇tak report. 263 p. (unpublished). özer, s., güngör, t., sari, b., sagular, e.k., görmüş, m. & özkar-öngen, i̇. (2017): cretaceous rudist-bearing platform carbonates from the lycian nappes (sw turkey): rudist associations and depositional setting.– cretaceous research, 79, 122–145. özgül, n. (1976): torosların bazı temel jeoloji özellikleri [some geological charac­ teristics of the taurides–in turkish].– türkiye jeoloji kurumu bülteni, 19, 65–78. özkaya, i̇. (1990): origin of the allochthons in the lycian belt, southwest turkey.– tectonophysics, 177, 367–379. özkaya, i̇. (1991): evolution of a tertiary volcanogenic trough in sw turkey – the alakaya basins of the lycien belt.– geologische rundschau, 80, 657–668. payros, a. & pujalte, v. (2008): calciclastic submarine fans: an integrated overview.– earth science reviews, 86, 203–246. doi: 10.1016/j.earscirev.2007.09.001 pérez rodríguez, i., lees, j.a., larrasoana, j.c., arz, j.a. & arenillas, i. (2012): planktonic foraminiferal and calcareous nannofossil biostratigraphy and magnetostratigraphy of the uppermost campanian and maastrichtian at zumaia, northern spain.– cretaceous research, 37, 100–126. doi: 10.1016/j.cretres.2012.03.011 petrizzo, m.r. (2003): late cretaceous planktonic foraminiferal bioevents in the tethys and in the southern ocean record: an overview.– journal of foraminiferal research, 23, 330–337. phillippson, a. (1910–1915): reisen und forschungen im westlichen kleinasien. – petermanns geographische mitteilungen/ergänzungsheft, 167–183. poisson, a. (1977): recherches géologiques dans les taurides occidentals (turquie) (ph.d. thesis): paris–sud (centre d’orsay), paris, 795 p. poisson, a. (1984): the extension of the ionian trough into southwestern turkey.– in dixon, j.e. & robertson, a.h.f. (eds.): the geological evolution of the eastern mediterranean, 241–249. doi: 10.1144/gsl.sp.1984.017.01.18 poisson, a. & sarp, h. (1977): la zone de kızlıca–çorakgöl–un exemple de sillon intra–plate–forme a la marge externe du massif du menderes.– in: izdar, e. & nakoman, e. (eds.): sixth colloquium on geology of the aegean region, ege university, i̇zmir, 555–564. postuma, j.a. (1971): manual of planktonic foraminifera.– elsevier publishing company, amsterdam, 420 p. pourteau, a., oberhänsli, r., candan, o., barrier, e. & vrielynck, b. (2016): neotethyan closure history of western anatolia: a geodynamic discussion.– international journal of earth sciences (geol rundsch), 105, 203–224. doi: 10.1007/s00531-015-1226-7 premoli silva, i. & sliter, w.v. (1994): cretaceous planktonic foraminiferal biostratigraphy and evolutionary trends from the bottacione section, gubbio, italy.– palaeontographia italica, 82, 1–89. premoli silva, i. & sliter, w.v. (1999): cretaceous paleoceanography: evidence from planktonic foraminiferal evolution.– in: barrera, e. & johnson, c.c. (eds.): the evolution of cretaceous ocean–climatic system. geological society of america, special paper, 332, 301–328. doi: 10.1130/0-8137-2332-9.301 premoli silva, i. & verga, d. (2004): practical manual of cretaceous planktonic foraminifera.– in: verga, d. & rettori, r. (eds.): international school on planktonic foraminifera, 3rd course: cretaceous. universities of perugia and milan, tiporafia pontefelcino, perugia (italy), 283 p. robaszynski, f. (1998): planktonic foraminifera–upper cretaceous, chart of cretaceous biochronostratigraphy.– in: de graciansky, p.c., hardenbol, j. & vail, p.r. (eds.): mesozoic and cenozoic sequence stratigraphy of european basins. society for sedimentary geology (sepm), special publication, 60, 782 p. robaszynski, f. & caron, m. (1995): cretaceous planctonic foraminifera: comments on the europe–mediterranean zonation.– bulletin de la société géologique de france, 166, 681–692. robaszynski, f., caron, m., gonzales donoso, j.m. & wonders, a.a.h. (1984): atlas of late cretaceous globotruncanids.– revue de micropaleontologie, 26, 145–305. robaszynski, f., gonzales donoso, j.m., linares, d., amedro, f., caron, m., dupuis, c., dhondt, a.v. & gartner, s. (2000): le crétacé supérieur de la région de kalaat senan, tunisie centrale. litho–biostratigraphie intégrée: zones d’ammonites, de foraminifères planctoniques et de nannofossiles du turonien supérieur au maastrichtien.– bulletin des centres de recherches ex-bulletin des centres de recherches exploration–production elf–aquitaine, 22, 359–490. sari, b. (2009): planktonic foraminiferal biostratigraphy of the coniacian–maastrichtian sequences of the bey dağları autochthon, western taurides, turkey: thin section zonation.– cretaceous research, 30/5, 1103–1132. sari, b. (2013): late maastrichtian–late palaeocene planktic foraminiferal biostratigraphy of the matrix of the bornova flysch zone around bornova (i̇zmir, western anatolia, turkey).– turkish journal of earth sciences, 22, 143–171. sari, b., kandemir, r., özer, s., walaszczyk, i., görmüş, m., demircan, h. & yilmaz, c. (2014): upper campanian calciclastic turbidite sequences from the hacımehmet area (eastern pontides, ne turkey): integrated biostratigraphy and microfacies analysis.– acta geologica polonica, 64/4, 393–418. sarigül, v., hakyemez, a., tüysüz, o., can genç, ş., yilmaz, i̇.ö. & özcan, e. (2017): maastrichtian–thanetian planktonic foraminiferal biostratigraphy and remarks on the k–pg boundary in the southern kocaeli peninsula (nw turkey).–turkish journal of earth sciences, 26, 1–29. sliter, w.v. (1989): biostratigraphic zonation for cretaceous planktonic foraminifers examined in thin section.– journal of foraminiferal research, 19, 1–19. doi: 10.2113/gsjfr.19.1.1 sofracioğlu, d. & kandemir, r. (2013): the upper cretaceous calciclastic submarine fan deposits in the eastern pontides, ne turkey: facies architecture and controlling factors.– turkish journal of earth sciences, 22, 588–610. soycan, h., erdoğan, k. & konak, n. (2015). aalenian–early bathonian (mid-aalenian–early bathonian (middle jurassic) radiolarian assemblages in the tavas nappe within lycian nappes in the western taurides (sw turkey): the first dating of carbonate platform drowning.– journal of asian earth sciences, 104, 3–21. şenel, m. (1991). likya napları içindeki volkanik katkılı paleosen–eosen çökelleri: faralya formasyonu [palaeocene–eocene sediments with volcanics intercalation in the lycian nappes: faralya formation – in turkish].– maden tetkik ve arama dergisi, 113, 1–16. şenel, m. (1997a): 1:100.000 ölçekli türkiye jeoloji haritaları no:1 fethiye–l7 paftası [1:250 000 scale geological maps of turkey no:1 fethiye l7 sheet – in turkish with an english abstract].– mta publications, 17 p. şenel, m. (1997b): 1:250.000 ölçekli türkiye jeoloji haritaları no:2 fethiye paftası [1:250 000 scale geological maps of turkey, no:2 fethiye sheet – in turkish with an english abstract].– mta publications, 26 p. şenel, m. (2007): characteristic features of the lycian nappes and their evolution. menderes massif colloqioum–proceedings, ankara, 51–55 (in turkish with english abstract). şenel, m., selçuk, h., bi̇lgi̇n, z.r., şen, m.a., karaman, t., di̇nçer, m.a., durukan, e., arbas, a., örçen, s. & bi̇lgi̇, c. (1989): çameli (denizli)– yeşilova (burdur)–elmalı (antalya) ve dolayının jeolojisi [geology of çameli (denizli)–yeşilova (burdur)–elmalı (antalya) and surroundings].– mineral research and exploration institute, report no. 9429, ankara (unpublished). şenel, m., akdeni̇z, n., öztürk, e.m., özdemi̇r, t., kadinkiz, g., meti̇n, y., öcal, h., serdaroğlu, m. & örçen, s. (1994): fethiye (muğla)–kalkan (antalya) ve kuzeyinin jeolojisi [geology of fethiye (muğla)–kalkan (an­ talya) and northern part].– mineral research and exploration institute, report no. 9761, ankara (unpublished). şengör, a.m.c., yilmaz, y. (1981): tethyan evolution of turkey: a plate tectonic approach.– tectonophysics, 75, 181–241. vandenberghe, n., hilgen, f.j. & speijer, r.p. (2012): the palaeogene period. in: gradstein, f.m., ogg, j.g., schmitz, m.d. & ogg, g.m. (eds.): the geologic time scale 2012, volume 2. amsterdam, the netherlands: elsevier, 855–921. van konijnenburg, j.h., wernli, r. & bernoulli, d. (1998): tentative biostratigraphy of palaeogene planktic foraminifera in thin section, an example from the gran sasso d’italia (central apennines, italy).– eclogae geol. helv., 91, 203–216. wright, v. r. (1986): facies sequences on a carbonate ramp: the carboniferous limestone of south wales.– sedimentology, 33, 221-241. doi: 10.1111/j.1365-3091.1986. tb00533.x http://services.chronos.org/foramatlas/pages/home.htm http://services.chronos.org/foramatlas/pages/home.htm g eo lo gi a c ro at ic a geologia croatica 70/3178 2023 | 76/1 | 37–46 | 7 figs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction long-lived lakes are often sites of endemic radiation in their various groups of biota. well-known examples include molluscs (e.g., haase & bouchet, 2006; wesselingh, 2007), that sometimes develop spectacular morphologies in such lakes, e.g., recent thalassoid snails in lake tanganyika (wilson et al., 2004) or molluscs of miocene lake pebas in south america (wesselingh et al., 2002). the late miocene – pliocene lake pannon, a large, deep, brackish lake in the intra-carpathian pannonian basin system, was also the habitat of a diverse endemic mollusc fauna (müller et al., 1999; neubauer et al., 2016). this fauna included some forms with highly unusual morphologies, such as the up to 10 cm long, thick-shelled dreissenid mussel congeria ungulacaprae (münster, 1837) (known as “goat’s hoof” to the locals), or the limpet-shaped, profundal dweller lymnaeid snail valenciennius rousseau, 1842 which could also grow up to 10 cm wide (e.g., ager, 1963, 1993). the most spectacular “freaks” from this lake, however, became widely known to the scientific public when gyula (‘julius’) halaváts, a geologist of the hungarian royal geological institute, discovered a new fossil locality near the small village of tirol, bánság/banat region, southeastern pannonian basin, in 1883 (halaváts, 1892; fig. 1). [the name of the locality became known as királykegye (hungarian) and königsgnade or königsgnad (german), referring to the act of franz i, emperor of austria, who settled exiled tyrolian freedom fighters here in 1810.] halaváts (1892) found a clay layer that had been deposited in the sublittoral zone of lake pannon and contained a diverse and well-preserved fauna of endemic cardiids, dreissenids, and deepwater-adapted lymnaeids. the most interesting member of the fauna was a cockle with spectaculary high, irregular, keeled radial ribs. in many specimens, the extreme part of the keel formed a t-shaped swelling in cross section, similar to the head of a railway track profile. halaváts (1892) recognized taxonomic revision of the lake pannon cockle subgenus lymnocardium (budmania) brusina, 1897 imre magyar1,2 and lajos katona3 1 elkh-mtm-elte research group for paleontology, budapest 2 mol hungarian oil and gas plc., budapest; (*corresponding author: immagyar@mol.hu) 3 natural history museum of the bakony mts., hungarian natural history museum, zirc; (katona.lajos@nhmus.hu) doi: 10.4154/gc.2023.01 abstract the lymnocardiine subgenus budmania is characterized by the most unusual and spectacular morphology in the endemic mollusc fauna of the late miocene – pliocene lake pannon. budmania possessed extremely high, hollow, irregular keels on its ribs, a pattern that was long considered an adaptation to the fluid, muddy substratum. eight species were described with this pattern between 1874 and 1973. our revision, based on the type materials and a large number of additional specimens from several collections, revealed however, that only two species can be distinguished with certainty: lymnocardium (budmania) ferrugineum (brusina, 1874) and l. (b.) cristagalli (roth, 1878). the former lived in the littoral zone of lake pannon, on a sandy substratum, whereas the latter inhabited the sublittoral zone with a muddy bottom. this habitat partitioning challenges the interpretation of the high, hollow keels as an adaptation to a soft, muddy substratum. the occurrence of both species seems to have been restricted to the period between 7.5-7.15 ma. this form as a new species and named it cardium (adacna) semseyi, in honor of andor semsey, a generous patron of earth sciences in hungary. this fossil was recovered in apparently unrestricted quantity from the layer, and specimens from tirol thus became treasured items in many fossil collections from bucharest to london and from vienna to washington. the extremely high, sometimes distally swollen, internally hollow keels with their multiple cavities challenged functional morphological interpretations. marinescu (1973) argued that the extreme size of the keels excludes any role in mechanical stregthening. he thought that the only adaptive significance of the keels was providing more stability to the large shells in a fluid mud. savazzi & sälgeback (2004) also discarded the mechanical enforcing role of the high ribs, and concluded that this peculiar sculpture served anchoring functions, preventing sinking within the water-laden, soupy, muddy sediment. specimens of lymnocardiine cockles with extraordinarily high keels from tirol and other localities were classified into eight species comprising a subgenus, budmania brusina, 1897. the authors of new species commonly failed to give clear differential diagnoses, and generally underestimated the high intraspecific variability, a pattern very characteristic of lake pannon endemic molluscs, including cardiids (e.g., müller & magyar, 1992). here, we revise these keeled lymnocardiines and discuss their palaeoenvironment, stratigraphic distribution, age, and possible evolutionary context. 2. taxonomic history in 1874, croatian palaeontologist s. brusina described a new species under the name cardium ferrugineum from remete (now a neighbourhood in the maksimir district of zagreb). his specimens were moulds (“steinkerns”) preserved in iron-stained sand, with the calcareous shell material completely dissolved (fig. 2). brusina did not depict the fossils, and gave only a very brief description: article history: manuscript received march 11, 2022 revised manuscript accepted november 28, 2022 available online february 23, 2023 keywords: mollusca, lake pannon, neogene, taxonomy, paleoecology, stratigraphy g eo lo gi a c ro at ic a geologia croatica 76/138 “cardium ferrugineum […] reaches the size of c. zagrabiense, resembles c. neumayri fuchs from matica north of ploeşti in wallachia [romania], but it can be easily distinguished at first glance from all other forms by its 5, rarely 6 to 7 high, lamellalike ribs, and by the ribless posterior part of the shell. the ribs are very similar to those of the recent c. (tropicardium) costatum l. […] from guinea and senegambia” (translated from german). four years later l. roth (1878) also published a description of a new species, cardium cristagalli, from multiple localities in southwestern hungary. his best-preserved specimens were found in the village of kurd (figs. 1, 3). roth (1878) compared his new species with brusina’s c. ferrugineum: “the species card. fer­ rugineum, proposed by brusina, as far as it can be judged from the very brief description, seems to be a close relative of c. cris­ tagalli […]. the ribs [of c. ferrugineum] are, according to brusina, very similar to those of c. (tropidocardium) costatum l., so they seem to be slightly different from the ribs of my new species. […] i had the opportunity to compare the original specimens of this cardium species living along the western coasts of africa with my fossils. i found that although the ribs of the two forms are similar in general, they are significantly different if details are observed. as i do not possess a drawing of c. ferrugineum, i am not in the position to say anything about any similarity of ribs between c. ferrugineum and c. cristagalli” (translated from hungarian). roth (1878) listed the additional localities around the mecsek mountains (southwestern hungary) where he and his colleague böckh collected c. cristagalli. its moulds (steinkerns) from iron-stained sand were recovered in hidas, németürög (now part of pécs), bükkösd, sormás, cserdi, zsibrik and pusztafalu (now part of lovászhetény), whereas its well-preserved shells were collected from bluish gray clay in bakóca and bükkösd. roth observed that specimens found in clay were always larger than those recovered from sand. he gave drawings of two specimens: one from a sand layer in kurd, and another, embedded into clay, from bükkösd (figs. 1, 3). in 1884, brusina described a new species, adacna meisi, based on a single, well-preserved right valve from zagreb–okrugljak. he noted that “perhaps my steinkerns that i described as cardium ferrugineum from remete belong to this species, but those fossils do not provide solid evidence for such a conclusion” (translated from german). brusina (1884) also described the highly keeled adacna histiophora from the clays of zagreb–okrugljak. in the description he referred to adacna cristagalli roth but did not present a comparison between the two species. halaváts (1892) argued that his new species, cardium (adacna) semseyi, belonged to the same group as cardium cris­ tagalli roth and adacna histiophora brusina. “the királykegye form is very closely related to both; they are all similar in their size, outline, number and spacing of radial ribs. the difference lies in the shape of the rib. the other two forms have evenly thin lamellae, whereas the királykegye form displays a thickened head at the top of the rib, similar to the cross-section of a railway track” (translated from hungarian). lőrenthey (1893), however, remarked that some thickening in the top of the lamellae is present in his l. cristagalli specimens from nagymányok, as well as in the sormás and bükkösd specimens (syntypes) of roth (1878). hoernes (1901) introduced the new name “limnocardium subferrugineum” for two right valves from tirol. he observed figure 1. the southern pannonian basin with confirmed localities of lymnocardium (budmania) ferrugineum (dots) and l. (b.) cristagalli (squares). the geographic distribution of the two species is restricted to the southern part of the basin where they largely overlap, and mark the position of the shelf in lake pannon between ca. 7.6 and 7.1 ma ago. 1) zagreb (remete and okrugljak), 2) jagnjedovac, 3) nyugotszenterzsébet, 4) ibafa, 5) bakóca, 6) bükkösd, 7) cserdi, 8) szentlőrinc, 9) pécs–cserebogár-dűlő, 10) kurd, 11) nagymányok, 12) hidas, 13) lovászhetény–pusztafalu, 14) himesháza, 15) paet-34p, 16) paet-29p, 17) paet-27, 18) paet-30, 19) novaci, 20) kuštilj, 21) tirol. g eologia c roatica magyar and katona: taxonomic revision of the lake pannon cockle subgenus lymnocardium (budmania) brusina, 1897 39 that “they are very closely related to the remete steinkerns described by brusina as cardium ferrugineum; they possibly belong together”(translated from german). hoernes (1901) claimed that l. semseyi is connected to l. cristagalli with transitional forms, and any distinction between the two forms would be arbitrary. he also claimed that there was no reason to distinguish l. histiophorum from l. cristagalli; the sail-like, triangular lamellae of the illustrated type specimen of l. histiophorum is presumably a pathological pattern which is not characteristic for all specimens of this species from okrugljak. in spite of these observations, he argued in favour of keeping the names “semseyi” and “cristagalli” denoting varieties (subspecies) with extreme morphologies. gorjanović-kramberger (1902) synonymized l. semseyi with l. histiophorum, coming to the conclusion that l. cristagalli and l. histiophorum are two subspecies (“varieties”) of the same, strongly variable species. he also argued that l. sub­ ferrugineum hoernes is identical to l. ferrugineum brusina. andrussoff (1903) went further: he claimed that b. meisi, b. cristagalli (the kurd form), b. histiophora and b. semseyi represent “vicariant forms” of one and the same species, each with its own distinct geographical distribution. in spite of these observations, all the above species names remained in use by subsequent authors. in fact, two new species names were introduced based on specimens from tirol. marinescu (1973) described limnocardium (budmania) aequico­ stata and l. (b.) obliquicosta, claiming that their types were first considered “aberrant individuals” or specimens with “distorted growth” of l. semseyi. brusina (1897) erected the subgenus budmania for the species “budmania histiophora” and “budmania meisi”, without further explanation or description. hoernes (1901) and gorjanović-kramberger (1902) disagreed with the idea of erecting a new subgenus for these species, because the character of the ribs is highly variable in all these forms, and because lym­ nocardium hungaricum and l. zagrabiensis, two species with moderately high ribs, were excluded from the subgenus. later authors, however, used budmania as a subgenus or genus for all lymnocardiines with extremely high, hollow ribs, i.e. for l. (b.) ferrugineum, l. (b.) cristagalli, l. (b.) histiophorum, l. (b.) meisi, l. (b.) semseyi, l. (b.) subferrugineum, l. (b.) aequicostata, and l. (b.) obliquicosta (e.g., marinescu 1973; stevanović 1990; basch 1990; savazzi & sälgeback 2004). 3. material in our revision, we used specimens from the following collections: croatian natural history museum, zagreb (hrvatski prirodoslovni muzej, hpm); natural history museum vienna (naturhistorisches museum wien, nhmw); supervisory authority of regulatory affairs, budapest (szabályozott tevékenységek felügyeleti hatósága, formerly geological institute of hungary, sztfh); and the hungarian natural history museum, budapest (magyar természettudományi múzeum, mtm). information on specimens was obtained from the collection of the university of graz (universität graz, ug). literature data was utilized from materials deposited in the geological institute of romania – national museum of geology, bucharest (institutul geologic al româniei – muzeul national de geologie, igrmng). 4. taxonomic decisions and their justification much confusion in the literature came from the fact that roth’s nominal species cardium cristagalli had a composite nature. roth (1878) failed to recognize that, in addition to size, there are several other consistent morphological differences between the sandand clay-associated specimens of c. cristagalli. in specimens from sand, the shell has a triangular or, rather, a quarter circle outline, the hinge is strongly curved in an s-shape, the posterior field is smooth, and all radial ribs curve anteriorly (as they run from the umbo towards the ventral margin). in contrast, specimens from clay sediments have an outline resembling a semi-circle, the hinge is straight to slightly sigmoidal, and the posterior field is covered with ribs that curve posteriorly. based on these consistent diagnostic features recognizable even in steinkerns and posterior fragments, the original syntypes of c. cristagalli (fig. 3) belong to two different species: the smaller, sand-associated form is identical with lymnocardium (b.) ferrugineum (brusina, 1874), whereas the larger, clay-associated form indeed represented a species that was new to science in 1878. later literature refers to either the kurd form or the bükkösd form, or both as c. cristagalli, causing ambiguities in identification. in order to avoid further confusion, we designate the specimen depicted by roth (1878, his fig. 2), found in clay at bükkösd, as the lectotype of l. cristagalli. we are entitled to do so particularly because the first scholar to further advocate this species name, lőrenthey (1890, 1893), applied the name for the bükkösd morphotype when identifying newly found specimens from nagymányok. the kurd specimens of roth (1878, his fig. 1) are identified as cardium ferrugineum brusina, 1874 herein. we share brusina’s (1884) original idea about the identity of his cardium ferrugineum and adacna meisi. thus, following the notion of hoernes (1901) and gorjanović-kramberger (1902), we regard both a. meisi and l. subferrugineum as subjective junior synonyms of cardium ferrugineum brusina. we also agree with hoernes (1901) and gorjanovićkramberger (1902) that c. cristagalli, a. histiophora and c. (a.) semseyi represent one highly variable species. we further argue that the diagnoses of l. (b.) aequicostata and l. (b.) obliqui­ costa by marinescu (1973) do not justify the erection of these new taxa. the very few features that marinescu (1973) mentions when comparing his new species to l. (b.) semseyi are not sufficient to distinguish his type specimens from other specimens of l. (b.) semseyi. the photographic illustrations do not provide such features either, and the author explicitly claims (in the case of l. (b.) obliquicosta) that there is a specimen that shows transitional character towards l. (b.) semseyi. in our view, marinescu’s type specimens only represent extreme morphological variants of l. (b.) semseyi. as a consequence, we claim that adacna his­ tiophora, cardium (adacna) semseyi, limnocardium (budmania) aequicostata and limnocardium (budmania) obliquicosta are all junior subjective synonyms of cardium cristagalli. systematic palaeontology genus lymnocardium stoliczka, 1870 type species: cardium haueri hörnes, 1861; od subgenus budmania brusina, 1897 type species: adacna histiophora brusina, 1884; sd, cossmann (1898) g eo lo gi a c ro at ic a geologia croatica 76/140 lymnocardium (budmania) ferrugineum (brusina, 1874) 1874 cardium ferrugineum brus. – brusina, p. 138. in part 1878 cardium cristagalli roth nov. sp. – roth, p. 54, pl. 4, fig. 1 (excl. fig. 2.) 1884 adacna ferruginea brusina – brusina, p. 138. 1884 adacna meisi brusina – brusina, p. 146, pl. 28, fig. 36. 1897 budmania meisi – brusina, p. 35, pl. 18, figs. 7, 8. 1901 limnocardium subferrugineum nov. form. – hoernes, p. 89, pl. 2, fig. 1; pl. 3, fig. 2. 1902 limnocardium (budmania) meisi brus. – gorja nović-kramberger, p. 9, pl. 2, fig. 3. 1902 limnocardium ferrugineum brus. – gor ja nović-kramberger, p. 11, pl. 1, figs. 1–6. 1903 limnocardium meisi brusina – andrussoff, p. 71, pl. 6, figs. 17–21. 1903 limnocardium crista galli roth – andrussoff, p. 72, pl. 7, figs. 10–12. 1933 limnocardium meissi brus. – šuklje, p. 16, pl. 1, fig. 1. non 1934 limnocardium ferrugineum brus. – poljak & šuklje, p. 17, pl. 2, fig. 1. 1968 limnocardium ferrugineum brus. – popović, p. 361, pl. 3, figs. 1–3. 1973 limnocardium (budmania) ferrugineum (brusi na) – ma rinescu, p. 21, pl. 6, fig. 2. 1990a limnocardium (budmania) meisi brusina – basch, p. 553, pl. 2, figs. 7–9. 1990b limnocardium (budmania) meisi (brusina) – basch, p. 54, pl. 16, figs. 3–5; pl. 17, fig. 5. in part 1990b limnocardium (budmania) ferrugineum (brusi na) – basch, p. 55, pl. 18, figs. 1–5, 7 (excl. figs. 6, 8) 1992 lymnocardium cristagalli (roth) – bujtor, p. 240, pl. 1, figs. 1, 2. 2015 lymnocardium ferrugineum – sztanó et al., p. 340, fig. 10e. 2018 lymnocardium ferrugineum – kovács et al., p. 339, pl. 1, figs. h, i. 2022 lymnocardium ferrugineum – radivojević et al., p.1561, fig. 7c type locality: zagreb–remete (district of maksimir). type material: syntypes (12 specimens) in hpm (5270-435/1-4, 5271-436.1-3, 5272-437.1-5). remarks: the syntypes of l. ferrugineum hold some uncertainty, because their original labels were lost. brusina (1874) did not originally specify the number of specimens that served as a basis for the description of the species, but 10 years later he claimed that there were 16 steinkerns of l. ferrugineum in the zagreb museum from remete (brusina 1884). gorjanovićkramberger (1902), who revised the subgenus budmania, wrote that “i had not only brusina’s originals at my disposal, but also sufficient comparative material”. we infer from this remark that all the remete specimens of l. ferrugineum in hpm, 4 of which were photographed and figured by gorjanovićkramberger (1902), are the syntypes of this species. of the paralectotypes of cristagalli that belong to ferrugi­ neum, some injured shells from kurd (pl.3145–3150, 3152; fig. 4/a, b) and steinkerns from hidas (pl.3037, 3039, 3041, 3042), figure 3. the first illustration of specimens of lymnocardium (budmania). this plate by roth (1878) clearly shows the difference between the two species of the subgenus. although roth (1878) considered both depicted specimens belonged to cardium cristagalli, we identify the upper specimen (1 a-c) from kurd as l. (b.) ferrugineum. the lower specimen (2) from bükkösd is designated herein as the lectotype of lymnocardium (b.) cristagalli. figure 2. lymnocardium (budmania) ferrugineum (brusina, 1874), syntypes from zagreb–remete. a: hpm 5271-436.3; b: hpm 5270-435. scale bar: 3 cm. g eologia c roatica magyar and katona: taxonomic revision of the lake pannon cockle subgenus lymnocardium (budmania) brusina, 1897 41 bükkösd (pl.2791–2793), cserdi (pl.2843), and lovászhetény– pusztafalu (pl.4360) are available at sztfh. the holotype of adacna meisi is reposited in the hpm (5011176/1, holotype by monotypy; milan et al. 1974; basch 1990). further specimens from zagreb-okrugljak are available in zagreb (hpm 5003-168.1-4; 5010-175.1-5; 3161/87; fig. 4f) and vienna (nhmw 1889/0002/0003; 1889/0002/0004; 1889/0002/0006; 1888/0014/0031; figs 4e, g, h). according to hoernes (1901), the two syntypes of lym­ nocardium subferrugineum from tirol were reposited in the collection of the university of graz, but they are presumed lost (b. hubmann, pers. comm. 2014). further specimens from tirol are figure 4. lymnocardium (budmania) ferrugineum (brusina, 1874). a, b: kurd (sztfh pl.3147 and 3150); c, d: paet-29p (mtm); e, g, h: zagreb–okrugljak (nhmw 1889/0002/0006; 1889/0002/0003; 1889/0002/0004); f: zagreb–okrugljak (hpm 175.1); i: tirol (nhmw 1900/0009/0050). scale bar: 3 cm. g eo lo gi a c ro at ic a geologia croatica 76/142 kept in vienna (nhmw 1900/0009/0050; fig. 4i), zagreb (hpm 4810-2450.2., gorjanović-kramberger 1902), and bucharest (igr-mng, marinescu 1973). distribution: confirmed occurrences (i.e. properly illustrated publications and collection materials studied here) include those from zagreb–remete (gorjanović-kramberger, 1902; basch, 1990b); kurd (roth, 1878; andrussoff, 1903); zagreb–okrugljak (brusina, 1884, 1897; basch, 1990a, 1990b; andrussoff, 1903); tirol/királykegye/königsgnad (hoernes, 1901; gorjanović-kramberger, 1902; marinescu, 1973); jagnjedovac (šuklje, 1933); kuštilj, (popo vić, 1968; radivojević et al., 2022); nyugotszenterzsébet (bujtor, 1992); bükkösd (sztanó et al., 2015); nagymányok (kovács et al., 2018); himesháza (budai et al., 2019); szentlőrinc (“l. cristagalli” by strausz, 1953, sztfh); pécs–cserebogárdűlő (possibly the same location as “németürög” in roth 1878; mtm); cserdi (sztfh, mtm); hidas (sztfh, mtm); pusztafalu (now part of lovászhetény, sztfh); and drill cores from near paks (paet-27, 29p, 30, 34p; mtm) (fig. 1). lymnocardium (budmania) cristagalli (roth, 1878) in part 1878 cardium cristagalli roth nov. sp. – roth, p. 54, pl. 4, fig. 2 (excl. fig. 1.) 1884 adacna histiophora brusina – brusina, p. 144, with text-fig. 1890 adacna cristagalli, roth – lőrenthey, p. 41, pl. 1, fig. 1. 1892 cardium (adacna) semseyi nov. sp. – halaváts p. 26, pl. 1, figs. 1–5. 1893 limnocardium cristagalli róth – lőrenthey, p. 121, pl. 5, fig. 4. 1897 budmania histiophora brus. – brusina, p. 34, pl. 18, figs. 4–6. 1901 lymnocardium semseyi halav. – hoernes, pl. 1, figs. 1, 2; pl 2, fig. 3; pl. 3, fig. 1. 1901 lymnocardium cristagalli roth – hoernes, pl. 2, fig. 2; pl. 3, fig. 3. 1902 limnocardium (budmania) histiophorum brus. – gorjanović-kramberger, p. 7, pl. 2, fig. 1. 1903 budmania histiophora brusina – andrussoff, p. 74, pl. 7, figs. 2, 3, 6. 1903 budmania semseyi halavats – andrussoff, p. 78, pl. 7, figs. 1, 4, 5, 7–9. figure 5. lymnocardium (budmania) ferrugineum (brusina, 1874). steinkerns from the mecsek mts. a, b: nyugotszenterzsébet (mtm); c: szentlőrinc (sztfh pl.2827); d, e: worn steinkerns (“pebbles”), himesháza (mtm). scale bars: 3 cm. figure 6. lymnocardium (budmania) cristagalli (roth, 1878). lectotype from bükkösd (sztfh pl.2789); width of the shell: 74 mm. the handwritten inscription says “drawn specimen”, with reference to fig. 2 of roth (1878) (see fig. 3 above). g eologia c roatica magyar and katona: taxonomic revision of the lake pannon cockle subgenus lymnocardium (budmania) brusina, 1897 43 1943 budmania cristagalli roth – gillet, p. 82, pl. 6, figs. 9, 9a. ? 1951 limnocardium (budmania) histiophora brus. – stevanović, p. 243, pl. 7, fig. 1. 1973 limnocardium (budmania) semseyi (halaváts) – marinescu, p. 22, pl. 6, figs. 3, 4; pl. 7, figs. 1–9. 1973 limnocardium (budmania) aequicostata sp. n. – marinescu, p. 24, pl. 8, fig. 4. 1973 limnocardium (budmania) obliquicosta sp. n. – marinescu, p 25, pl. 8, figs. 1, 3. ? 1990 limnocardium (budmania) cf. histiophora brus. – stevanović & škerlj, p. 171, pl. 1, figs. 12, 13. figure 7. specimens of lymnocardium (budmania) cristagalli (roth, 1878). a–d: syntypes of l. semseyi (halaváts, 1892) from tirol/királykegye (sztfh pl.60); e: steinkern from ibafa (mtm); f: tirol/königsgnad (nhmw 1900/0009/0057); g: lectotype of l. histiophorum (brusina, 1884) from zagreb–okrugljak (hpm 4998-163); h, i: zagreb–okrugljak (nhmw 1888/0014/0029a, b). scale bar: 3 cm. g eo lo gi a c ro at ic a geologia croatica 76/144 1990 limnocardium (budmania) histiophora brusina – stevanović, p. 481, pl. 6, fig. 4. 1990a limnocardium (budmania) histiophora brusi na – basch, p. 553, pl. 2, fig. 6. 1990b limnocardium (budmania) histiophorum (brusina) – basch, p. 53, pl. 16, figs 6, 7; pl. 17, figs. 1–4. 2000 lymnocardium (budmania) semseyi (halaváts) – geary et al., p. 470, figs. 5/3, 4. 2004 budmania semseyi (halaváts) – savazzi & sälgeback, p. 228, figs. a–d, f, h–o. 2004 budmania cf. aequicostata (marinescu) – savazzi & sälgeback, p. 228, fig. g. 2007 lymnocardium (budmania) semseyi – wesselingh, p. 294, fig. 18. 2015 lymnocardium cristagalli – sztanó et al., p. 340, fig. 9b. 2019 lymnocardium cristagalli (roth) – budai et al., p. 2011, figs. 8k, 8l. type locality: bükkösd, mecsek mts. type material: lectotype, designated herein (pl.2789; fig. 6) and paralectotypes (pl.3144, 3153 from bakócza; pl.2790 from bükkösd) in sztfh. remarks: although milan et al. (1974) indicated the originally figured specimen of l. histiophorum as a holotype, it was a syntype because brusina (1884) based his description on two specimens. the better preserved syntype (hpm 4998-163; fig. 7g) is designated herein a lectotype, because the other synytpe, an imprint with shell fragments (brusina, 1884), could not be identified and confirmed in hpm. further specimens from okrugljak are available in zagreb (hpm 160-167, 169-174, altogether 30 specimens) and in vienna (nhmw 1888/0014/0029; fig. 7h,i). the syntypes of l. semseyi from tirol are reposited in sztfh (pl.60; fig. 7a-d). further specimens from tirol are available in hpm, nhmw (fig. 7), sztfh, mtm, igr-mng, ug, naturalis – leiden (wesselingh, 2007), natural history museum – london (savazzi & sälgeback, 2004), smithsonian natural history museum – washington, etc. according to marinescu (1973), the holotype of l. aequi­ costata is in his own collection, whereas two paratypes are available in hpm (2465.1 and 2465.2), labelled as l. rothi. the holotype of l. obliquicosta is reposited in igr-mng (3347), whereas paratypes were selected from the collection of nhmw (without numbers) and from the collection of the author of the species (also without numbers), plus a specimen in igrmng (3391) (marinescu, 1973). distribution: confirmed occurrences (i.e. properly illustrated publications and collection materials studied here) include those from bükkösd (roth, 1878); bakóca (sztfh); zagreb– okrugljak (brusina, 1884, 1897; andrussoff, 1903; gorjanović-kramberger, 1902; basch, 1990a, 1990b); nagymányok (lőrenthey, 1890, 1893); királykegye/ königsgnad/tirol (halaváts, 1892; hoernes, 1901; andrussoff, 1903; gillet, 1943; marinescu, 1973; geary, et al. 2000; savazzi & sälgeback, 2004; wesselingh, 2007); novaci (stevanović, 1990); ibafa (sztanó et al., 2015); himesháza (budai et al., 2019) and, possibly, blatno (stevanović & škerlj, 1990) (fig. 1). 5. discussion 5.1. environment and adaptation although specimens of lymnocardium (b.) ferrugineum are known from the classic sites of zagreb–okrugljak and tirol where l. (b.) cristagalli is common, the two species usually occur in different sedimentary rocks and with different accompanying species. lymnocardium (b.) ferrugineum is typically found in fine very fine sands, which are interpreted to have been deposited in shallow-water, littoral and deltaic environments ( sztanó et al. 2015; kovács et al. 2018; budai et al. 2019; radivojević et al. 2022). the most common associated species, such as congeria triangularis partsch, dreissenomya schroeckingeri (fuchs), dreissena serbica brusina, proso­ dacnomya dainellii (brusina), lymnocardium szaboi lőrenthey, l. pelzelni (brusina), l. ochetophorum (brusina), pseudocatillus simplex (fuchs), viviparus sp. and others are considered shallow-water dwellers (e.g., stevanović, 1951; popović, 1968; müller & szónoky, 1990; müller & magyar, 1992; bujtor, 1992; sztanó et al., 2015; kovács et al., 2018; budai et al., 2019). in contrast, lymnocardium (b.) cristagalli commonly occurs in clays and silts, deposited below the wave-base, in the sublittoral zone of lake pannon (sztanó et al., 2015; budai et al., 2019). the associated species include, for example, congeria rhomboidea hörnes, c. zagrabiensis brusina, lymnocardium majeri (hörnes) and valenciennius reussi (neumayr) (brusina, 1884; halaváts, 1892; popović, 1968; budai, 2019), i.e. forms that were adapted to the sublittoral depth of lake pannon (korpás-hódi, 1983; lennert et al., 1999; cziczer et al., 2009). lymnocardium (b.) ferrugineum and l. (b.) cristagalli thus inhabited different environments. the specimens of l. (b.) fer­ rugineum that have been recovered from the offshore deposits of zagreb–okrugljak and tirol may have been transported from the shallow to the deeper environment, although no signs of mechanical wear were observed in their shells. lymnocardium (b.) cris­ tagalli, however, does not occur in shallow-water sediments. this relatively strict habitat partitioning between the two coeval species strongly challenges the interpretation of the high, hollow keels as an adaptation to fluid, muddy substratum (marinescu, 1973; savazzi & sälgeback, 2004). 5.2. geographical distribution, stratigraphy and age the subgenus budmania is geographically restricted to the southern part of the pannonian basin (fig. 1); when it first appeared, the northern part of the basin had already been infilled by sediments (magyar, 2021). lymnocardium (b.) ferrugineum occurs together with proso­ dacnomya dainellii (brusina) in several localities (kurd, nyugotszenterzsébet, cserdi and paks (paet drill cores), according to roth, 1878, bujtor, 1992, and our own observations), therefore its stratigraphic range seems to be restricted to the p. dainellii zone (müller & magyar, 1992; magyar, 2021). the only report of its co-occurrence with the younger prosodacnomya vutskitsi (brusina) came from jagnjedovac (šuklje 1933). in that paper, however, prosodacnomya vutskitsi and p. dainellii are treated as a single species, thus leaving the biostratigraphic assignement (p. dainellii zone or p. vutskitsi zone) uncertain. in the magnetostratigraphically dated and seismically correlated paet drill cores at paks, the lowermost occurrence of g eologia c roatica magyar and katona: taxonomic revision of the lake pannon cockle subgenus lymnocardium (budmania) brusina, 1897 45 lymnocardium (b.) ferrugineum is in paet-29p, 207.7 m, which corresponds to an age of 7.5 ma. the uppermost occurrence in the paks cores is in paet-34p, 177.6 m, having an age of 7.15 ma (kelder et al., 2018; magyar et al., 2019). lymnocardium (b.) cristagalli, a sublittoral dweller, occurs together with congeria rhomboidea hörnes and is thus restricted to the congeria rhomboidea zone (8–?4.5 ma; magyar & geary, 2012; mandic et al., 2015). lymnocardium (b.) cris­ tagalli was not found in the paks paet cores, and its occurence was not magnetostratigraphically dated in other locations either. the first appearance and last occurrence of this species is thus difficult to assess. in some transgressive successions, however, l. (b.) cristagalli appears directly above the basal shallow-water deposits with prosodacnomya dainellii and lymnocardium ferrugineum (bükkösd, nagymányok; cf. roth, 1878; lőrenthey, 1890, 1893; sztanó et al., 2015; kovács et al., 2018), whereas in others, its occurrence is directly followed by regressive deltaic sediments with l. ferrugineum (vršac mts., himesháza; halaváts, 1892; popović, 1968; budai et al., 2019). in both cases, its first appearance in the succession is very close to that of l. (b.) ferrugineum, suggesting a largely overlapping stratigraphic range of the two species. the geographic distribution of budmania thus reflects the position of the shelf of lake pannon between ca. 7.5 and 7.15 ma (fig. 1). 5.3. evolutionary relationships brusina (1897) introduced the new subgenus budmania for lymnocardium (b.) histiophorum (= l. (b.) cristagalli) and lym­ nocardium (b.) meisi (=l. (b.) ferrugineum). although not stated explicitly, the shared feature of the two species that justified their distinction as a new subgenus was the spectacularly high, hollow keel. because the two species lived in different environments, the evolution of the keel is therefore difficult to interpret as an adaptive trait that evolved independently in unrelated lineages. the characteristic and complex keel with its multiple cavities is probably a shared derived character (synapomorphy) between the two species and indicates their monophyletic origin. the currently available data on the stratigraphic distribution of the two species do not provide evidence as to which of them appeared earlier. lymnocardium (budmania) ferrugineum, however, shows a striking morphological similarity to lymnocardium (lymnocardium) inflatum (gorjanović-kramberger, 1899) in size, shape, number of ribs, curved hinge and smooth posterior field. the only obvious difference is the lack of high keels in l. (l.) inflatum. although poljak & šuklje (1934) reported the co-occurrence of l. (l.) inflatum and l. (b.) ferrugi­ neum from glogovnica, in our view all the glogovnica specimens belong to l. (l.) inflatum, thus no sympatric occurrence of the two species is known. lymnocardium (l.) inflatum is stratigraphically restricted to the shallow-water lymnocardium (l.) decorum zone (orešac: stevanović, 1951, 1990) and the younger prosodacnomya carbonifera zone (kötcse: müller & magyar, 1992). the magnetostratigraphically dated and seismically correlated age of its occurrence in the paet-26 drill core is 7.8-7.9 ma (magyar et al., 2019). based on the above data, we hypothesize the following phylogeny for the subgenus budmania. lymnocardium (l.) inflatum evolved anagenetically into l. (b.) ferrugineum sometime between 7.8 and 7.5 ma in the littoral zone of lake pannon. soon after, l. (b.) cristagalli appeared in the deeper, offshore environment, probably through allopatric speciation from l. (b.) ferrug­ ineum. both budmania species were likely to have become extinct before 7.15 ma, because their occurrence in younger layers has not yet been confirmed. 6. conclusions two out of the eight species names, introduced for various specimens of the subgenus budmania, such as cardium ferrugineum, cardium cristagalli, adacna meisi, limnocardium subferrugi­ neum, adacna histiophora, cardium (adacna) semseyi, limno­ cardium (budmania) aequicostata and limnocardium (budma­ nia) obliquicosta, are accepted as valid species names: lymnocardium (budmania) ferrugineum (brusina, 1874) and l. (b.) cristagalli (roth, 1878). both species seem to have been restricted in time to between 7.5–7.15 ma. l. (b.) ferrugineum probably evolved from l. (l.) inflatum and gave rise to l. (b.) cristagalli. l. ferrugineum was a shallow-water dweller in lake pannon, whereas l. cristagalli populated offshore, sublittoral environments. the widely held notion that the spectacularly high, keeled ribs of these cockles reflect adaptation to soft muddy substrate thus cannot be maintained. acknowledgement our work on the museum collections was supported by klára palotás, lászló makádi, bálint szappanos (sztfh); oleg mandic, mathias harzhauser (nhmw); katarina krizmanić and marija bošnjak (hpm). martin gross and bernhard hubmann kindly provided information on the ug collection. for taxonomic and iczn issues, we were advised by philippe bouchet (muséum national d’histoire naturelle, paris) and barna páll-gergely (elkh agrártudományi kutatóközpont, budapest). reviewers simon schneider and oleg mandic are thanked for their large effort to improve the original manuscript. this research was funded by the national research, development and innovation office (nkfih) project 143787. this is mta-mtm-elte paleo contribution no. 368. references ager, d.v. (1963): principles of paleoecology.– mcgraw-hill, new york, 371 p. ager, d.v. (1993): the new catastrophism.-cambridge university press, cambridge, 231 p. andrussoff, n. (1903): studien über die brackwassercardiden. lieferung 1.– mémoires de l’académie impériale des sciences de st.-pétersbourg, viiie série, classe physico-mathématique, 13/3, 1–82. basch, o. (1990a): die molluskenfauna der pontischen stufe in kroatien.– in: stevanović, p.m., nevesskaja, l.a., marinescu, fl., sokač, a. & jámbor, á. (eds.): chronostratigraphie und neostratotypen. neogen der westlichen („zentrale”) paratethys viii, pl1, pontien, jazu and sanu, zagrebbeograd, 538–557. basch, o. (1990b): cardiidae (mollusca, lamellibranchiata) pontskog kata u hrvatskoj (cardiidae (mollusca, lamellibranchiata) der pontischen stufe in kroatien).– palaeontologia jugoslavica, 39, 1–158. brusina, s. (1874): fossile binnen-mollusken aus dalmatien, kroatien und slavonien.– agram, druck der actienbuchdruckerei, zagreb, 144 p. brusina, s. (1884): die fauna der congerienschichten von agram in kroatien.– beiträge zur geologie und paläontologie österreich-ungarns und orients, 3, 125–187. brusina, s. (1897): matériaux pour la faune malacologique néogéne de la dalmatie, de la croatie et de la slavonie avec des espéces de la bosnie, de l’herzégovine et de la serbie.– imprimerie fondée par actions, zagreb, 43 p. with 21 plates. budai, s., sebe, k., nagy, g., magyar, i. & sztanó, o. (2019): interplay of sediment supply and lake-level changes on the margin of an intrabasinal basement high in the late miocene lake pannon (mecsek mts., hungary).– international journal of earth sciences, 108, 2001–2019. doi: 10.1007/s00531-019-01745-3 bujtor, l. (1992): an upper pannonian (pontian, neogene) mollusc fauna from the western mecsek hills, hungary.– ann. univ. sci. budapest, sect. geol., 29, 237–262. g eo lo gi a c ro at ic a geologia croatica 76/146 cossmann, m. (1898): revue critique de paléozoologie 2.– paris, 190 p. cziczer, i., magyar, i., pipík, r., böhme, m., ćorić, s., bakrač, k., sütő-szentai, m., lantos, m., babinszki, e. & müller, p. (2009): life in the sublittoral zone of long-lived lake pannon: paleontological analysis of the upper miocene szák formation, hungary.– international journal of earth sciences, 98, 1741–1766. doi: 10.1007/s00531-008-0322-3 geary, d.h., magyar, i. & müller, p. (2000): ancient lake pannon and its endemic molluscan fauna (central europe; mio-pliocene).– in: rossiter, a. & kawanabe, h. (eds.): ancient lakes: biodiversity, ecology, and evolution. advances in ecological research, 3, 463–482. doi: 10.1016/s00652504(00)31025-x gillet, s. (1943): les limnocardiidés des couches à congéries de roumanie.– memoriile institutului geologic al româniei, 4, 1–118. gorjanović-kramberger, k. (1902): über budmania brus. und andere oberpontische limnocardien kroatiens.– sitzungsberichte der kaiserlichen akademie der wissenschaften in wien, mathematisch-naturwissenschaftliche classe, 111, 5–25. haase, m. & bouchet, ph. (2006): the radiation of hydrobioid gastropods (caenogastropoda, rissooidea) in ancient lake poso, sulawesi.– hydrobiologia, 556, 17–46. halaváts, j. (1892): paläontologische daten zur kenntnis der fauna der südungarischen neogen-ablagerungen vi. die pontische fauna von királykegye.– mittheilungen aus dem jahrbuche der königlichen ungarischen geologischen anstalt, 10, 27–45. hoernes, r. (1901): über limnocardium semseyi halav. und verwandte formen aus den oberen pontischen schichten von königsgnad (királykegye).– sitzungsberichte der kaiserlichen akademie der wissenschaften in wien, mathematisch-naturwissenschaftliche klasse, 110, abt. 1, 78–94. kelder, n.a., sant, k., dekkers, m.j., magyar, i., van dijk, g.a., lathouwers, y.z., sztanó, o. & krijgsman, w. (2018): paleomagnetism in lake pannon: problems, pitfalls, and progress in using iron sulfides for magnetostratigraphy.– geochemistry, geophysics, geosystems, 19, 3405–3429. doi: 10.1029/2018gc007673 korpás-hódi, m. (1983): palaeoecology and biostratigraphy of the pannonian mollusca fauna in the northern foreland of the transdanubian central range. a dunántúli-középhegység északi előtere pannóniai mollusca faunájának paleoökológiai és biosztratigráfiai vizsgálata.– annals of the hungarian geological institute, 66, 1–163. kovács, á., sebe, k., magyar, i., szurominé korecz, a. & kovács, e. (2018): pannóniai üledékképződés és szerkezeti mozgások az északi-pikkely (kelet-mecsek) területén. upper miocene sedimentation and tectonics in the northern imbricate zone (eastern mecsek mts, sw hungary).– földtani közlöny, 148, 327–340. doi: 10.23928/foldt.kozl.2018.148.4.327 lennert, j., szónoky, m., gulyás, s., szuromi-korecz, a., shatilova, i.i., sütő-szentai, m., geary, d.h. & magyar, i. (1999): the lake pannon fossils of the bátaszék brickyard.– acta geologica hungarica, 42, 67–88. lőrenthey, e. (1890): die pontische stufe und deren fauna bei nagy-mányok im comitate tolna.– mittheilungen aus dem jahrbuche der königlich ungarischen geologischen anstalt, 9, 35–50. lőrenthey, i. (1893): a szegzárdi, nagy-mányoki és árpádi felső-pontusi lerakódások és faunájok.– a magyar királyi földtani intézet évkönyve, 10, 67–142. german translation: lőrenthey, e. (1894): die oberen pontischen sedimente und deren fauna bei szegzárd, nagy-mányok und árpád. mittheilungen aus dem jahrbuche der kön. ungarischen geologischen anstalt, 10, 73–160. magyar, i. (2021): chronostratigraphy of clinothem-filled non-marine basins: dating the pannonian stage.– global and planetary change, 205, 103609. doi: 10.1016/j. gloplacha.2021.103609 magyar, i. & geary, d.h. (2012): biostratigraphy in a late neogene caspian-type lacustrine basin: lake pannon, hungary.– in: baganz, o.w., bartov, y., bohacs k. & nummedal, d. (eds.): lacustrine sandstone reservoirs and hydrocarbon systems. aapg memoir, 95, 255–264. doi: 10.1306/13291392m953142 magyar, i., sztanó, o., sebe, k., katona, t.l., csoma, v., görög, á., tóth, e., szuromi-korecz, a., sujan, m., braucher, r., ruszkiczay-rüdiger, zs., koroknai, b., wórum, g., sant, k., kelder, n. & krijgsman, w. (2019): towards a high-resolution chronostratigraphy and geochronology for the pannonian stage: significance of the paks cores (central pannonian basin).– földtani közlöny, 149, 351–370. doi: 10.23928/ foldt.kozl.2019.149.4.351 mandic, o., kurečić, t., neubauer, t.a. & harzhauser, m. (2015): stratigraphic and palaeogeographic significance of lacustrine molluscs from the pliocene viviparus beds in central croatia.– geologia croatica, 68/3, 179–207. doi: 10.4154/gc.2015.15 marinescu, fl. (1973): les mollusques pontiens de tirol (banat roumain).– institut géologique, mémoires, 18, 7–56. milan, a., sakač, k. & žagar-sakač, a. (1974): katalog originala tipova vrsta pohranjenih u geološko-paleontološkom muzeju u zagrebu. katalog der im geologisch-paläontologischen museum in zagreb aufbewahrten originale von artentypen.geološko-paleontološki muzej u zagrebu, zagreb, 186 p. müller, p. & szónoky, m. (1990): faciostratotype the tihany-fehérpart (hungary) (“balatonica beds”, by lőrenthey, 1905).– in: stevanović, p.m., nevesskaja, l.a., marinescu, fl., sokać, a. & jámbor, á. (eds.): chronostratigraphie und neostratotypen. neogen der westlichen („zentrale”) paratethys viii, pl1, pontien, jazu and sanu, zagreb-beograd, 427–435. müller, p. & magyar, i. (1992): continuous record of the evolution of lacustrine cardiid bivalves in the late miocene pannonian lake.– acta palaeontologica polonica, 36, 353–372. müller, p., geary, d.h. & magyar, i. (1999) the endemic molluscs of the late miocene lake pannon: their origin, evolution, and family-level taxonomy.– lethaia, 32, 47–60. doi: 10.1111/j.1502-3931.1999.tb00580.x neubauer, t.a, harzhauser, m., mandic, o., kroh, a. & georgopoulou, e. (2016): evolution, turnovers and spatial variation of the gastropod fauna of the late miocene biodiversity hotspot lake pannon.– palaeogeography, palaeoclimatology, palaeoecology, 442, 84–95. doi: 10.1016/j.palaeo.2015.11.016 popović, r. (1968): some new evidence on the development of the upper pontian in southern banat.– vesnik zavoda za geološka i geofizička istraživanja, series a, 24–25, 309–316. radivojević, d., radonjić, m., katona, l.m. & magyar, i. (2022): against the tide: southeast to northwest shelf-edge progradation in the southeastern margin of lake pannon, banat (serbia and romania).– international journal of earth sciences, 111, 1551–1571. doi: 10.1007/s00531-022-02188-z roth, l. (1878): egy új cardium-faj az úgynevezett “congeria-rétegekből”. ein neues cardium aus den sogenannten „congerien-schichten”.–természetrajzi füzetek, 2, 53–56, 66–70. savazzi, e. & sälgeback, j. (2004): a comparison of morphological adaptations in the cardiid bivalves cardium and budmania.– paleontological research, 8, 221–239. doi: 10.2517/prpsj.8.221 stevanović, p.m. (1951): pontische stufe im engeren sinne – obere congerienschichten serbiens und der angrenzenden gebiete. serbische akademie der wissenschaften, sonderausgabe 187, mathematisch-naturwissenschaftliche klasse no. 2, beograd, 361 p. stevanović, p.m. (1990): die pontische halbbrackische molluskenfauna aus serbien und bosnien.– in: stevanović, p.m., nevesskaja, l.a., marinescu, fl., sokač, a. & jámbor, á. (eds.): chronostratigraphie und neostratotypen. neogen der westlichen („zentrale”) paratethys viii, pl1, pontien, jazu and sanu, zagreb-beograd, 462–537. stevanović, p. & škerlj, ž. (1990): the pontian sediments in slovenia.– in: stevanović, p.m., nevesskaja, l.a., marinescu, fl., sokač, a. & jámbor, á. (eds.): chronostratigraphie und neostratotypen. neogen der westlichen („zentrale”) paratethys viii, pl1, pontien, jazu and sanu, zagreb-beograd, 153–179. stoliczka, f. (1870): cretaceous fauna of southern india. volume 3, nos. 1–4: the pelecypoda.– memoirs of the geological survey of india: palaeontologia indica, calcutta, 1–222. strausz, l. (1953): felső-pannóniai ősmaradványok pécs környékéről (oberpannonversteinerungen aus der umgebung von fünfkirchen).– földtani közlöny, 83, 163–168. šuklje, f. (1933): pontijska fauna jagnjedovca i glogovca u hrvatskoj.– vesnik geol. inst. kralj. jugosl. za 1932, 57–82. sztanó, o., sebe, k., csillag, g. & magyar, i. (2015): turbidites as indicators of paleotopography, upper miocene lake pannon, western mecsek mountains (hungary).– geologica carpathica, 66, 331–344. doi: 10.1515/geoca-2015-0029 wesselingh, f. (2007): long-lived lake molluscs as island faunas: a bivalve perspective.– in: renema, w. (ed.): biogeography, time, and place: distributions, barriers, and islands. springer netherlands, topics in geobiology, 29, 275–314. doi: 10.1007/978-1-4020-6374-9_9 wesselingh, f.p., räsänen, m.e., irion, g., vonhof, h.b., kaandorp, r., renema, w., romero pittman, l. & gingras, m. (2002): lake pebas: a palaeoecological reconstruction of a miocene, long-lived lake complex in western amazonia.– cainozoic research, 1, 35–81. wilson, a.b., glaubrecht, m. & meyer, a. (2004): ancient lakes as evolutionary reservoirs:evidence from the thalassoid gastropods of lake tanganyika.– proc. royal society london b, 271, 529–536. doi: 10.1098/rspb.2003.2624 2023 | 76/1 | 13–36 | 12 figs. | 5 tabs. | 1 supp. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the study is focused on the metasedimentary succession of the palaeozoic-mesozoic metamorphic complex (pmmc) of medvednica mountain (mt.) north of the city of zagreb. the investigated metasediments are part of the jadar-kopaonik thrust sheet (basch, 1983a,b; karamata, 2006; schmid et al., 2008) (fig. 1), which originated at the continental margin of the adria microplate promontory and are located along the present day contact of the tisia and adria microplates (schmid et al., 2008; 2020, schefer et al., 2010 and references therein). between these microplates, the opening and extension of the neotethys occurred from the middle triassic to the middle jurassic, during which time intra-oceanic subduction occurred (babić et al., 2002; pamić, 2002; karamata, 2006; schmid et al., 2008; 2020; šegvić et al., 2014; 2020). this subduction was followed by an accretion process and the subsequent obduction of neotethys crust resulting in the formation of ophiolites (west vardar ophiolites sensu schmid et al., 2008; 2020, and references therein) at the continental margin of adria (cma). geochemistry and mineralogy of metasediments usually provide valuable information on the nature of the protolith and its metamorphic evolution. therefore, we conducted a petrochronological study on the metasedimentary succession of the pmmc to better understand its evolution. the study primarily focuses on a sample containing chloritoid as an index mineral of the highest metamorphic grade in metasediments on medvednica mt. chloritoid schists of medvednica mt. were earlier reported by vragović & majer (1979a,b), who described the petrog petrochronological study of chloritoid schist from medvednica mountain (zagorje mid-transdanubian zone, croatia) ivan mišur*1, dražen balen2, urs klötzli3, mirko belak1, hans-joachim massonne4,5, mihovil brlek1 and vlatko brčić1 1 croatian geological survey, department of geology, sachsova 2, hr-10000 zagreb, croatia (*corresponding author e-mail: imisur@hgi-cgs.hr) 2 university of zagreb, faculty of science, department of geology, division of mineralogy and petrology, horvatovac 95, hr-10000 zagreb, croatia 3 university of vienna, faculty of earth sciences, geography and astronomy, department of lithospheric research, josef-holaubek-platz 2 (uza ii), 1090 wien, austria 4 university of stuttgart, faculty of chemistry, pfaffenwaldring 55, 70569 stuttgart, germany 5 school of earth sciences, china university of geosciences, lumo road 388, wuhan, 430074, china doi: 10.4154/gc.2023.02 abstract the metamorphic conditions and evolution of the palaeozoic-mesozoic metamorphic complex of medvednica mountain (zagorje-mid-transdanubian zone, croatia) are still a matter of debate. the results of the investigation of five samples of metapelitic schists with the mineral association of quartz, white mica and chlorite are presented. the studied schists are part of the continental margin of adria and were metamorphosed under upper greenschistto amphibolite-facies conditions. the focus of this study is a sample representing the highest metamorphic grade that additionally contains chloritoid blasts. pressure-temperature pseudosection modelling together with classical geothermobarometric calculations yielded peak metamorphic conditions of 0.94 ± 0.05 gpa and 550 ± 20 °c for chloritoid schist. monazite in-situ u-th-total pb electron microprobe dating indicates two metamorphic events at 167 ± 2 ma and 143 ± 2 ma, which are interpreted as the time of monazite growth during two distinct metamorphic phases. the formation of the chloritoid paragenesis is related to the older event (around 167 ma) and linked with the middle jurassic subduction-accretion processes of neotethys-derived ophiolitic lithologies. the younger metamorphic event (around 143 ma) is related to the obduction of ophiolites onto the continental margin of adria. raphy and presented the chemical whole-rock compositions of their samples but without stating either a stratigraphic correlation or position within the pmmc of medvednica mt. mišur et al. (2013) presented petrographic and whole rock analyses of the chloritoid schist from the southeastern slopes of medvednica mt. we aimed to distinguish metamorphic records in the chloritoid schist. all samples in this study were analysed by petrographic microscope, followed by whole-rock analyses, whereas further chemical analyses of minerals were only carried out on the chloritoid-bearing sample. this research considers the possibility that the investigated metasedimentary succession of the pmmc could have recorded polymetamorphic overprinting of the aforementioned complex; a prograde phase, developed during the jurassic subduction and collision of adria and europe (i.e. tisia) (lanphere et al., 1975; okrusch et al., 1978; dimolahitte et al., 2001; schmid et al., 2008; 2020; šegvić et al., 2014; 2020; belak et al., 2022) and a subsequent retrograde phase in the early cretaceous (110 – 125 ma) related to ophiolite obduction onto the cma during the final stage of ocean closure (van gelder et al., 2015; belak et al., 2022). 2. geological setting the middle triassic opening of the neotethys ocean was followed by intermediate and basic volcanism (pamić, 1984; schmid et al., 2008; van gelder et al., 2015; slovenec et al., 2020 and references therein). the passive continental margin of eastern adria was formed simultaneously and is characterised mainly by siliciclastic and carbonate sedimentation article history: manuscript received april 20, 2021 revised manuscript accepted december 12, 2022 available online february 23, 2023 keywords: medvednica mountain, zagorje mid-transdanubian zone, chloritoid, geothermobarometry, monazite g eo lo gi a c ro at ic a geologia croatica 76/114 (pamić, 1984; schmid et al., 2008; van gelder et al., 2015). during the late middle jurassic, intra-oceanic subduction in the neotethys realm resulted in the formation of an accretionary wedge and thrusting of ophiolitic units forming a mélange (babić et al., 2002; schmid et al., 2008, 2020; slovenec et al., 2010; šegvić et al., 2014; van gelder et al., 2015). later on, during the late jurassic – early cretaceous, jurassic ophiolite lithologies (i.e. western vardar sensu schmid et al., 2008; 2020) were obducted onto the cma (pamić, 2002; babić et al., 2002; karamata, 2006; schmid et al., 2008; 2020). these events influenced the subsequent geological setup of the central part of medvednica mt. medvednica mt. is situated in an area where dinaridic, carpathian, and alpine units came into contact (fig. 1). this area is known as the zagorje–mid–transdanubian zone (zmtz after pamić & tomljenović, 1998), which evolved during the cretaceous-palaeogene collision of the adria microplate with the european margin (pamić, 2002; ustaszewski et al., 2009; toljić et al., 2013). the zmtz was the major regional shear zone in the oligocene-pliocene, where the northern tip of the dinaridic units was rotated clockwise from a nw-se to a ne-sw orientation (schmid et al., 2008; tomljenović et al., 2008; ustaszewski et al., 2008; van gelder et al., 2015). the northern boundary of the zmtz is the periadriatic transcurrent fault merging eastward into the balaton line (fodor et al., 1998; haas et al., 2000; tomljenović et al., 2008; and reference therein). the southern border of the zmtz is the zagreb-zemplin lineament which forms the border to the tisia-dacia megablock (csontos & nagymarosy, 1998; fodor et al., 1998; haas et al., 2000) (fig. 1). medvednica mt. is composed of exhumed jurassic ophiolitic lithologies that were obducted onto the pmmc and covered by cretaceous and tertiary sediments (fig. 2) (šikić et al., 1978; 1979; basch, 1983a,b; babić et al., 2002; judik et al., 2004; lugović et al., 2006; tomljenović et al., 2008; van gelder et al., 2015). the pmmc consists of metasediments, which were originally shale, sandstone, limestone, and chert interstratified with basalt and tuff, and was affected by several deformation events (belak et al., 1995a,b; judik et al., 2004; lugović et al., 2006; tomljenović et al., 2008; van gelder et al., 2015). according to tomljenović et al. (2008), these events were: (1) the aptian–albian nappe stacking in the central–northern dinarides, (2) early albian orogen-perpendicular shortening, (3) e–w shortening that took place after the palaeocene; and (4) right–lateral n–s shearing that was interpreted to be related to the right–lateral shearing of the sava zone during the eocene–oligocene (pamić & tomljenović, 1998; tomljenović, 2002; tomljenović et al., 2008). the metamorphic conditions of the pmmc were determined using the kübler index (judik et al., 2004), the chlorite empirical thermometer and vitrinite reflectance thermometry (lugović et al., 2006; judik et al., 2008). the temperature range of metamorphism of the pmmc was 300 – 410 °c, obtained using the kübler index method (judik et al., 2004; 2008) and 300 – 350 °c by applying chlorite geothermometry in metabasites (lugović et al., 2006). vragović & majer (1979b) assumed metamorphic p-t conditions for chloritoid schist up to figure 1. the regional geological position of medvednica mountain, compiled after schmid et al. (2016). sa – southern alps; ophiolitic units: sz – sava zone; wv – western vardar units; ev – eastern vardar units; adria derived units: pk&bf – pre-karst & bosnian flysch zone; ebd – east bosnian durmitor; di – drina ivanjica units; jk – jadar kopaonik units. yellow ellipse marks the position of the medvednica mt. g eologia c roatica mišur et al.: petrochronological study of chloritoid schist from medvednica mountain (zagorje mid-transdanubian zone, croatia) 15 500 ℃ and 5 – 6 kbar. these pressure conditions are consistent with medium pressures derived from the b0 unit cell dimension of potassic white mica (judik et al., 2004). only on the northeast slopes of medvednica mt., blueschist-facies metamorphic rocks occur (belak & tibljaš, 1998). this study on chloritoid schist from the metasedimentary sequence of the pmmc is based on a sample taken from the southern slope of medvednica mt. in the source area of the stari potok creek (fig. 2). the outcrop comprises metapelites to minor metapsammitic rocks and sparse metapsephitic interlayers. further up the sequence from this outcrop, the metasedimentary succession is in unconformable contact with tectonized metavolcanics, which are locally intercalated with recrystallized limestone dated by fossils to the middle triassic (belak, 2005). based on macroscopic investigations, five samples (st-1, st-2, st-4, st-5, st-6) were chosen for petrographic and whole-rock analyses. in addition, a chloritoid schist (sample st-6) was chosen for monazite dating, thermodynamic modelling and mineral analyses. 3. materials and methods 3.1. whole-rock chemistry the five selected specimens were powdered; air-dried powders were sieved through a 0.125 mm stainless-steel screen. wholerock geochemical data were provided by the bureau veritas commodities canada ltd. the sample preparation procedure included melting of 0.2 g rock powder mixed with lithium metaborate/ tetraborate (libo2/li2b4o7) and subsequent dissolution in aqua regia. uncertainties for the analysis of the prepared solution by inductively coupled plasma optical emission spectroscopy (icpoes) of the major elements range from 0.01 – 0.002 wt %. the trace-element uncertainties for the analyses by inductively coupled plasma mass spectrometry (icp-ms) are assumed to be in the range of 8 – 0.05 ppm with an exception for gold (au) analysed with an uncertainty of 0.0005 ppm. the rare-earth element (ree) data were normalized to chondrite (boynton, 1984); other trace-element data were normalized to the upper continental crust (taylor & mclennan, 1995). graphical presentation of selected data was undertaken using gcdkit v.4.1. (janoušek et al., 2006). 3.2. mineral chemistry quantitative analyses of minerals were obtained with a cameca sx100 emp at the institute for mineralogy and crystal chemistry, university of stuttgart (institut für mineralogie und kristallchemie, universität stuttgart), germany. operating conditions were: accelerating voltage of 15 kv, a beam current of 15 na, and a beam diameter of about three μm with 20 s counting time (both peak and background). standards for the measurements were natural minerals and pure oxides (albite, corundum, fayalite, periclase, barite, chromium oxide, wollastonite, orthoclase, rutile, rhodonite). results were corrected using the pap correction procedure provided by cameca (pouchou & pichoir, 1984; 1991). analytical uncertainties are reported in massonne (2012). x-ray compositional maps were produced simultaneously for several elements (fe, mg, mn) by area mapping under conditions of 50 na, 15 kv, 60 ms per step, and step width of 3 μm. the analytical procedure was described in massonne et al. (2012) and li et al. (2021). 3.3. monazite dating analyses of monazite were conducted with a cameca sx100 emp at the state geological institute of dionýz štúr, slovakia using 15 kv accelerating voltage and 180 na beam current. the counting times at peak position for the following elements were: 300 s for pb, 35 s for th, 80 s for u, 40 s for y, and 20 – 60 s for rees with longer times for the heavier rees, 120 s for as, 20 s for fe and sr, and 10 s for s, p, ca, al, and si. calibration was figure 2. a simplified geological map of medvednica mt. (modified after tomljenović, et al., 2008). the cross indicates the sampling site. on the right hand side is a simplified schematic geological column of the palaeozoic-mesozoic metamorphic complex (pmmc) of the medvednica mt., the white circle with the cross marks sample location (modified after belak et al., 2022). g eo lo gi a c ro at ic a geologia croatica 76/116 conducted with natural (apatite, wollastonite) and synthetic materials, glasses, and pure oxides (al2o3, sio2, (ree)po4, uo2, tho2) as reported in massonne (2014). the data were processed by the chemical th–u–total pb isochron method described in montel et al. (1996) and suzuki & kato (2008). the presented uncertainties refer to 2σ confidence limits. final calculations and data presentation were accomplished with the aid of “isoplotr” (vermeesch, 2018). 3.4. p-t calculations 3.4.1. classical thermobarometry the empirical geothermometer for chlorite–chloritoid pairs (vidal et al., 1999), was applied to the chloritoid schist sample (st-6). this geothermometer is based on the mg-fe2+ exchange between these minerals. the compositional criteria, <1 wt % mno and <2 wt % (cr2o3 + mno + cao + na2o + k2o) in chlorite and chloritoid pairs, are fulfilled for this sample. also, the main assumption of equilibrium between chlorite and chloritoid pairs is achieved by measuring these minerals in contact, or close to each other, at the rim of corresponding grains (vidal et al., 1999). chlorite thermometry is based on the content of tetrahedrally coordinated al in chlorite. vidal et al. (2016) argued that this type of geothermometry results in geologically relevant temperature estimates for chlorite formed at low temperatures (<300 c°) under the assumption that all iron is ferrous. however, at higher formation temperatures, calculated temperatures can scatter (vidal et al., 2016). we used the most recent calibration by inoue et al. (2018). phengite barometry, as experimentally calibrated by massonne & schreyer (1989) and massonne & szpurka (1997), was applied according to caddick & thompson (2008). this temperature-dependent barometer is based on incorporating mg and fe2+ in potassic white mica according to tschermak’s substitution. 3.4.2. pseudosections – thermodynamic modelling isochemical phase diagrams (i.e. pseudosections) were constructed with perple_x (version 6.8.8. downloaded from: http:// www.perplex.ethz.ch/, connolly, 1990; 2005; connolly & petrini, 2002). the p-t range of 0.2 to 1.2 gpa and 300 to 600 °c and the system mnnckfmashto (mno–na2o–cao– k2o–feo–mgo–al2o3–sio2–h2o–tio2–o2) were considered. the water content was increased to excess, presuming that watersaturated conditions prevailed at peak p-t conditions. for the perple_x calculations, the whole-rock composition of st-6 had to be adjusted: (1) iron and o2 were corrected for different fe3+ contents, for instance, to fit the assumption that 10% of iron was trivalent during metamorphism (see lo pò & braga, 2014), (2) phosphorus was eliminated, but a proportional quantity of calcium was subtracted from the whole-rock analysis as this element is mainly bound in apatite (ca5(po4)3oh, a correction was not performed for other phosphates as their abundances are minor compared to apatite), and (3) the whole-rock composition including the selected h2o content was normalized to 100%. the solid-solution models by white et al. (2014) were used: bi(w) for biotite, chl(w) for chlorite, crd(w) for cordierite, ctd(w) for chloritoid, gt(w) for garnet, ilm(wph) for ilmeni te, mica(w) for white mica, st(w) for staurolite. for feldspars, the model by fuhrman & lindsley (1988) was applied. contouring of the p-t pseudosections by isopleths for the si content in phengite, fe content in chlorite and fe content in chloritoid was also achieved with the perple_x software. 4. results 4.1. petrography of the samples five samples of metasediments were collected from the lithological succession in the vicinity of the source of the stari potok (tab. 1). the only sample with chloritoid (st-6), occurring at the top of this succession at a small outcrop (fig. 3a), was chosen for a detailed study of the peak metamorphic conditions. the four other selected samples are quartz schist (st-1, st-4) and quartzsericite-chlorite schist (st-2, st-5), for which no mineral analyses were performed (tab. 1). the minerals in samples st-2 and st-5 comprise ca. 60 vol% quartz, ca. 30 vol% white mica (without distinguishing between muscovite, paragonite, margarite and celadonite following parry et al., 1984; arbiol et al., 2021), ca. 5 vol% chlorite, and ca. 3 vol% plagioclase. the rest is dominated by opaque minerals. samples st-1 and st-4 comprise ca. 80 vol% quartz and ca. 15 – 20 vol% white mica; the rest is composed mainly of chlorite and opaque minerals. the s1 foliation is pronounced in all the investigated schists. samples st-2 and st-5 are lepido-granoblastic, consisting of micro-lithons composed of quartz and plagioclase, and show cleavage domains mainly composed of syn-metamorphic white mica, chlorite, and opaque minerals. zircon, apatite, tourmaline and rutile were found as accessory phases in all samples. chloritoid schist st-6 is grey in colour and has silky lustre (due to the high content of white mica). foliation and cleavage are easily discernible, (fig. 3b). the sample contains chloritoid porphyroblasts visible as dark, short prismatic grains. major minerals observed in sample st-6 are quartz (ca. 70 vol%), white mica (ca. 15 vol%), chloritoid (ca. 10 vol%), chlorite (ca. 3 vol%), and opaque minerals (ca. 1 – 2 vol%). accessory phases are zircon, baddeleyite (usually as zircon overgrowth), rutile, apatite, tourmaline, monazite, and xenotime. two distinct mineralogical domains occur which are either mainly composed of white mica or recrystallized quartz-rich micro-lithons. the shape and orientation of white mica flakes and quartz micro-lithons indicate a ‘c-type shear band cleavage microstructure (fig. 3c) (passchier & trouw, 2005). microstructure s1 is recognized as a metamorphic structure parallel to c’-type shear bands (fig. 3c) and mica-rich cleavage domains (passchier & trouw, 2005). remnant sedimentary bedding planes (s0) are not discernible. chloritoid porphyroblasts are 0.5 – 2 mm in diameter and show a hypidiomorphic shape (fig. 3c; d; e). syntectonic growth is evident in rotated and fractured porphyroblasts (fig. 3c; d; e). chloritoid grains are characterized by polysynthetic twins, hourglass-sector zoning, and rare radial aggregates (fig. 3c; d; e). this zoning is ascribed to fast growth along non-{001} faces resulting in the incorporation of inclusions, while the growth along {001} faces is table 1. locations of samples st-1, st-2, st-4, st-5, st-6 and their analysis. sample northing easting description applied methods st-1 5085642 460049 quartz, schist/metapelite pet; wr; st-2 5085788 459964 quartz, chloritic to sericitic schist/metapelite pet; wr; st-4 5085808 459724 quartz, schist/metapelite pet; wr; st-5 5085796 459685 quartz, chloritic to sericitic schist/metapelite pet; wr; st-6 5085804 459623 quartz, chloritoid, chlorite, sericite schist/ metapelite pet; wr; empa (coordinates are presented in htrs96 reference system, epsg: 3765) (pet – petrographical investigation under polarising microscope; wr – whole rock analysis; empa – electron microprobe analysis) g eologia c roatica mišur et al.: petrochronological study of chloritoid schist from medvednica mountain (zagorje mid-transdanubian zone, croatia) 17 figure 3. photographs of chloritoid schist from medvednica mt. (sample st-6). a) outcrop of the chloritoid schist; the yellow circle marks the sampling location. b) hand specimen of the chloritoid schist (dark grains are chloritoid crystals). c) photomicrograph of sample st-6; cyan lines mark the s1 foliation and red lines c’ shear bands. d) photomicrograph of sample st-6 (crossed polarizers), fractured chloritoid grain of prismatic habitus with visible hourglass sector zoning; on the right hand side is the same object seen under plane polarized light. e) photomicrograph of chloritoid with quartz pressure shadows; on the right hand side is the same object seen under plane polarized light. f) photomicrograph with visible quartz recrystallization boundaries (crossed polarizers); on the right hand side is the same features seen under plane polarized light. g eo lo gi a c ro at ic a geologia croatica 76/118 slower ensuring enough time for dissolution and dispersion of excess material (vernon, 2004; camilleri, 2018). strain shadows filled with polygonal and elongated quartz are discerned at the boundary of chloritoid grains (fig. 3d). quartz grains are equigranular, with sharp polygonal, slightly elongated boundari es, often oriented parallel to s1, indicating subgrain rotation recrystallization (sgr) and grain boundary migration recrystallization (gbm, fig. 3f) (passchier & trouw, 2005). quartz is preferentially bounded by white mica (fig. 3f). chlorite grains are mostly elongated with polygonal boundaries and are up to 250 μm in size. monazite grains are of highly irregular shape (amoeboid, lobate and elongated grain shapes prevail) and small in size (<200 μm). these grains are located in the mica-rich domains. 4.2. whole-rock chemistry results of the whole-rock analyses are presented in table 2. sio2 contents are between 75.0 wt% (st-1) and 88.3 wt% (st-2). total iron ranges from 1.07 wt% fe2o3 (st-5) to 5.38 wt% fe2o3 (st-1). the ree patterns of the samples normalized to chondrite (boynton, 1984) are similar in all the studied samples, showing higher values of light rees compared to heavy rees ((la/sm)n = 4.8 – 6.5) and negative eu anomalies (eu/eu* = 0.65 – 0.78) (see fig. 4). on the diagram of the trace elements normalized to upper continental crust (ucc, taylor & mclennan, 1995), ba, ta, nb and particularly sr show negative anomalies (fig. 4). chloritoid schist st-6 is characterized by similar values of the major and trace elements as the chloritoid-free samples (tab. 2; fig. 4). 4.3. chemistry of the main minerals in the chloritoid schist compositions of chlorite in sample st-6 are presented in table 3a. the chlorite formula was calculated on the basis of 14 oxygen atoms. all iron was considered as fe2+. due to the small size of the grains, the possible zonation of chlorite remains ambiguous. table 2. bulk rock compositions for samples: st-1, st-2, st-4, st-5, and st-6. for comparison samples of chloritoid schists, d7 (mišur et al., 2013) and vrma (vragović & majer, 1979b) were added. sample st 1 st 2 st 4 st 5 st 6 d 7 vrma major elements (wt%) chloritoid containing schist sio2 74.98 88.29 75.86 85.65 83.86 74.79 65.75 al2o3 10.96 4.94 10.92 8.38 8.67 13.22 20.43 fe2o3 5.38 2.40 6.59 1.07 3.27 4.73 4.83 mgo 1.55 0.89 0.69 0.42 0.42 0.99 1.79 cao 0.15 0.24 0.97 0.03 0.06 0.08 na2o 1.16 0.82 0.12 0.37 0.08 0.14 0.86 k2o 1.84 0.59 1.04 1.90 1.47 2.50 2.51 tio2 0.72 0.26 0.62 0.48 0.40 0.70 0.90 p2o5 0.11 0.18 0.09 0.02 0.05 0.05 0.02 mno 0.05 0.06 0.13 <0.01 0.04 0.05 0.05 cr2o3 0.02 0.01 0.01 0.00 0.00 0.01 loi 3.00 1.30 2.90 1.60 1.60 2.70 3.18 sum 99.87 99.95 99.94 99.92 99.95 99.96 100.32 trace elements (ppm) ba 219.00 138.00 188.00 251.00 165.00 300.00 be <1 1.00 2.00 1.00 3.00 1.00 co 11.20 11.30 7.40 2.20 2.60 5.10 cs 3.20 0.80 1.90 3.20 1.80 4.30 ga 11.20 4.60 11.00 6.70 8.30 15.30 hf 9.30 3.00 4.60 9.10 4.90 6.20 nb 9.20 4.10 8.60 8.40 6.80 12.30 figure 4. chondrite normalized ree patterns (ree in chondrite after boynton, 1984) at the top, and upper continental crust normalized spider diagram (traceelements in upper continental crust, after taylor & mclennan, 1995) at the bottom, for the studied metasediments from medvednica mt.. the sample in blue is d7 chloritoid schist from mišur et al. (2013) and the sample in red is the chloritoid schist (st-6) from this study. g eologia c roatica mišur et al.: petrochronological study of chloritoid schist from medvednica mountain (zagorje mid-transdanubian zone, croatia) 19 ni 39.60 27.00 28.00 <20 <20 24.00 sc 11.00 4.00 9.00 3.00 5.00 12.00 sr 23.90 12.40 16.80 46.90 20.40 40.70 ta 0.70 0.30 0.70 0.90 0.60 1.00 th 7.50 4.10 7.70 8.50 7.80 9.40 u 1.80 1.70 2.10 1.90 1.60 1.90 v 95.00 77.00 78.00 33.00 51.00 95.00 w 1.50 0.90 2.00 1.80 1.50 2.10 zr 337.40 105.10 167.10 331.60 179.30 208.90 y 18.80 16.20 16.70 15.00 19.00 21.00 la 20.30 13.60 19.70 16.30 19.00 20.20 ce 43.20 25.10 39.00 30.40 36.90 49.30 pr 5.02 3.32 4.75 3.86 4.68 5.54 nd 17.90 13.50 17.10 13.80 17.40 20.80 sm 3.52 2.82 3.55 2.51 3.51 3.82 eu 0.75 0.75 0.71 0.53 0.71 0.82 gd 3.48 3.03 3.19 2.38 3.01 3.36 tb 0.56 0.48 0.59 0.39 0.54 0.58 dy 3.27 2.84 3.34 2.32 3.62 3.74 ho 0.63 0.53 0.65 0.48 0.74 0.77 er 2.08 1.53 1.77 1.37 2.12 2.22 tm 0.29 0.24 0.28 0.24 0.35 0.32 yb 2.26 1.62 1.83 1.72 2.17 2.30 lu 0.35 0.24 0.27 0.28 0.32 0.34 mo 0.30 0.90 <0.1 <0.1 <0.1 cu 47.50 27.90 0.50 0.60 0.30 rb 73.40 23.30 37.30 76.10 45.60 89.40 pb 5.40 8.50 0.70 1.40 4.30 zn 92.00 19.00 19.00 8.00 5.00 ni 39.60 22.60 17.00 4.20 1.30 24.00 as 4.60 12.80 0.50 1.00 <0.5 cd 0.10 <0.1 <0.1 <0.1 <0.1 sb <0.1 <0.1 0.40 <0.1 <0.1 bi <0.1 0.40 0.10 <0.1 <0.1 ag <0.1 <0.1 <0.1 <0.1 <0.1 au (ppb) 0.90 <0.5 1.10 <0.5 0.80 hg 0.01 <0.01 <0.01 0.02 <0.01 tl <0.1 <0.1 <0.1 <0.1 <0.1 se <0.5 0.60 <0.5 <0.5 <0.5 sio2/al2o3 6.84 17.87 6.95 10.22 9.67 k2o/na2o 1.59 0.72 8.67 5.14 18.38 na2o/k2o 0.63 1.39 0.12 0.19 0.05 zr/hf 36.28 35.03 36.33 36.44 36.59 zr/sc 30.67 26.28 18.57 110.53 35.86 zr/th 44.99 25.63 21.70 39.01 22.99 th/co 0.67 0.36 1.04 3.86 3.00 th/sc 0.68 1.03 0.86 2.83 1.56 th/u 4.17 2.41 3.67 4.47 4.88 co/th 1.49 2.76 0.96 0.26 0.33 hf/sc 0.85 0.75 0.51 3.03 0.98 la/co 1.81 1.20 2.66 7.41 7.31 la/y 1.08 0.84 1.18 1.09 1.00 la/yb 8.98 8.40 10.77 9.48 8.76 la/sc 1.85 3.40 2.19 5.43 3.80 la/sm 5.77 4.82 5.55 6.49 5.41 la/th 2.71 3.32 2.56 1.92 2.44 y/ni 0.47 0.72 0.98 3.57 14.62 (la/yb)n 8.98 8.40 10.77 9.48 8.76 (la/sm)n 5.77 4.82 5.55 6.49 5.41 (gd/yb)n 1.54 1.87 1.74 1.38 1.39 eu/eu* 0.66 0.78 0.65 0.66 0.67 sree 103.61 69.60 96.73 76.58 95.07 d7 sample from mišur et al. (2013.), vrma sample from vragović & majer (1979 b) g eo lo gi a c ro at ic a geologia croatica 76/120 ta bl e 3a . s el ec te d m ic ro pr ob e an al ys es o f c hl or ite in th e in ve st ig at ed c hl or ito id sc hi st fr om m ed ve dn ic a m t. ch lo rit e w t% 115 118 119 123 125 127 130 146 148 153 212 249 26 241 29 238 214 23 243 219 21 225 216 245 m in m ax av r si o 2 24 .0 5 24 .3 1 23 .9 2 23 .8 9 24 .0 0 23 .9 4 23 .7 2 24 .7 0 23 .6 6 23 .8 3 23 .6 3 23 .6 6 23 .6 8 23 .6 8 23 .6 8 23 .7 9 23 .9 1 23 .9 3 23 .9 6 23 .9 7 24 .1 1 24 .1 2 25 .1 8 25 .3 1 23 .6 3 25 .3 1 24 .0 3 ti o 2 0. 02 0. 03 0. 04 0. 05 0. 04 0. 01 0. 02 0. 02 0. 02 0. 05 0. 06 0. 04 0. 04 0. 02 0. 05 0. 03 0. 06 0. 01 0. 03 0. 02 0. 04 0. 02 0. 05 0. 03 0. 01 0. 06 0. 03 a l 2o 3 23 .1 4 22 .2 6 23 .2 9 23 .0 4 23 .2 5 23 .2 3 23 .2 9 22 .8 2 23 .4 3 23 .0 7 23 .3 5 23 .1 9 23 .1 5 23 .0 1 23 .8 1 23 .4 3 23 .4 4 23 .7 0 23 .3 3 23 .5 2 23 .6 3 24 .2 7 23 .9 9 24 .6 1 22 .2 6 24 .6 1 23 .3 9 cr 2o 3 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 04 0. 05 0. 01 0. 01 0. 03 0. 06 0. 04 0. 02 0. 04 0. 01 0. 00 0. 03 0. 02 0. 07 0. 00 0. 07 0. 02 fe o 27 .3 6 26 .5 1 28 .5 7 28 .5 6 27 .6 1 27 .6 1 27 .2 8 27 .2 0 28 .8 9 29 .0 8 27 .2 7 27 .5 9 26 .9 7 25 .8 9 27 .4 7 27 .7 3 27 .1 8 27 .1 1 25 .8 5 27 .7 0 26 .9 9 26 .6 8 26 .1 4 25 .8 1 25 .8 1 29 .0 8 27 .2 9 m no 0. 14 0. 11 0. 17 0. 16 0. 17 0. 17 0. 21 0. 15 0. 14 0. 12 0. 16 0. 15 0. 18 0. 17 0. 12 0. 11 0. 09 0. 13 0. 17 0. 12 0. 22 0. 11 0. 14 0. 13 0. 09 0. 22 0. 15 m go 13 .3 6 14 .0 3 12 .7 2 11 .8 7 13 .1 9 12 .7 2 12 .8 6 12 .5 8 12 .0 6 11 .9 6 12 .9 6 13 .0 7 13 .1 4 13 .9 1 12 .8 5 12 .3 0 12 .4 6 12 .8 3 13 .6 6 12 .3 5 13 .4 7 11 .8 5 12 .2 6 11 .2 7 11 .2 7 14 .0 3 12 .7 4 to ta l 88 .0 8 87 .2 6 88 .7 0 87 .5 7 88 .2 6 87 .6 8 87 .3 8 87 .4 8 88 .2 0 88 .1 1 87 .4 7 87 .7 5 87 .1 7 86 .6 8 88 .0 1 87 .4 5 87 .1 8 87 .7 3 87 .0 4 87 .6 8 88 .4 6 87 .0 8 87 .8 0 87 .2 3 si 2. 55 2. 59 2. 54 2. 57 2. 54 2. 56 2. 54 2. 63 2. 53 2. 55 2. 53 2. 53 2. 54 2. 54 2. 52 2. 55 2. 56 2. 54 2. 55 2. 56 2. 54 2. 57 2. 65 2. 67 2. 52 2. 67 2. 56 a l t ot 2. 89 2. 80 2. 91 2. 92 2. 90 2. 92 2. 94 2. 87 2. 95 2. 91 2. 94 2. 92 2. 92 2. 91 2. 98 2. 96 2. 96 2. 97 2. 93 2. 96 2. 93 3. 05 2. 97 3. 06 2. 80 3. 06 2. 94 iv a l 1. 45 1. 41 1. 46 1. 43 1. 46 1. 44 1. 46 1. 37 1. 47 1. 45 1. 47 1. 47 1. 46 1. 46 1. 48 1. 45 1. 44 1. 46 1. 45 1. 44 1. 46 1. 43 1. 35 1. 33 1. 33 1. 48 1. 44 vi a l 1. 45 1. 39 1. 44 1. 48 1. 45 1. 48 1. 48 1. 50 1. 48 1. 46 1. 47 1. 44 1. 46 1. 45 1. 50 1. 50 1. 52 1. 51 1. 48 1. 51 1. 47 1. 62 1. 62 1. 73 1. 39 1. 73 1. 50 ti 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 fe 2+ 2. 43 2. 37 2. 53 2. 57 2. 45 2. 46 2. 44 2. 42 2. 58 2. 60 2. 44 2. 46 2. 42 2. 32 2. 44 2. 48 2. 43 2. 41 2. 30 2. 47 2. 38 2. 38 2. 30 2. 28 2. 28 2. 60 2. 43 m n 0. 01 0. 01 0. 01 0. 01 0. 02 0. 02 0. 02 0. 01 0. 01 0. 01 0. 01 0. 01 0. 02 0. 02 0. 01 0. 01 0. 01 0. 01 0. 02 0. 01 0. 02 0. 01 0. 01 0. 01 0. 01 0. 02 0. 01 m g 2. 11 2. 23 2. 01 1. 90 2. 08 2. 02 2. 05 2. 00 1. 92 1. 91 2. 07 2. 08 2. 10 2. 22 2. 03 1. 96 1. 99 2. 03 2. 17 1. 96 2. 11 1. 88 1. 92 1. 77 1. 77 2. 23 2. 02 so ct . (f e. m g, a lv i) 5. 99 5. 99 5. 99 5. 95 5. 98 5. 97 5. 97 5. 92 5. 98 5. 97 5. 97 5. 99 5. 98 5. 99 5. 97 5. 95 5. 94 5. 96 5. 96 5. 95 5. 97 5. 89 5. 84 5. 78 5. 78 5. 99 5. 95 sv ac .o ct . 0. 01 0. 01 0. 01 0. 05 0. 02 0. 03 0. 03 0. 08 0. 02 0. 03 0. 03 0. 01 0. 02 0. 01 0. 03 0. 05 0. 06 0. 04 0. 04 0. 05 0. 03 0. 11 0. 16 0. 22 0. 01 0. 22 0. 05 xf e= fe /( fe +m g+ m n) 0. 53 0. 51 0. 56 0. 57 0. 54 0. 55 0. 54 0. 55 0. 57 0. 58 0. 54 0. 54 0. 54 0. 51 0. 55 0. 56 0. 55 0. 54 0. 52 0. 56 0. 53 0. 56 0. 54 0. 56 0. 51 0. 58 0. 55 xm g 0. 47 0. 49 0. 44 0. 43 0. 46 0. 45 0. 46 0. 45 0. 43 0. 42 0. 46 0. 46 0. 46 0. 49 0. 45 0. 44 0. 45 0. 46 0. 48 0. 44 0. 47 0. 44 0. 46 0. 44 0. 42 0. 49 0. 45 ch lo rit e fo rm ul ae c al cu la te d on b as is o f 1 4 ox yg en a to m s a nd a ll iro n w as c on si de re d as f e2 +. * ∑o ct .(f e, m g, a lv i) is th e su m o f c at io ns in th e oc ta he dr al p os iti on , * *∑ va c. o ct . r ep re se nt s v ac an ci es a t t he o ct ah ed ra l p os iti on s. g eologia c roatica mišur et al.: petrochronological study of chloritoid schist from medvednica mountain (zagorje mid-transdanubian zone, croatia) 21 the composition of chlorite is characterized by feo and mgo contents between 25.8 and 29.1 wt% and 11.3 and 14 wt%, respectively (24 measurements, tab. 3a). the average composition of chlorite shows 1.44 atoms per formula unit (apfu) of tetrahedrally coordinated al. average xfe = fe2+/(mg+fe2++mn) is 0.55. the abundances of ti and mn are almost negligible (tab. 3a). the chemical compositions of chlorite show a uniform pattern and correspond to the ripidolite-chamosite series on the octahedral fe/(fe+mg) versus tetrahedral al diagram after foster (1962) and bailey (1980) as shown in figure 5a. according to the ternary mg – (al+vac oct.) – fe2+ diagram after zane & weiss (1998), chlorite is a trioctahedral (type i) fe-chlorite (fig. 5b). the ternary (fe+mg) – si – altot diagram after abd elmola et al. (2017) confines the analysed chlorites between daphnite and amesite (fig. 5c). nine emp analyses were performed on white mica. only grains of metamorphic origin, characterized by polygonal, elongated and hypidiomorphic habitus, were analysed. the possible zonation of grains remains unclear because of the minute size of the micas. all analyses are given in table 3b. the structural formula is based on 11 oxygen, resulting in si values between 3.06 and 3.11 apfu, na = 0.07 – 0.08 apfu, fe2+ = 0.12 – 0.17 apfu, and interlayer occupancies of 0.93 – 0.99 apfu (tab. 3b). these values classify the white mica in sample st-6 as muscovite (after arbiol et al. 2021 and references therein). on the al vs. fe+mg+si (apfu) binary diagram, analysed micas follow tschermak’s substitution (fig. 6b). by the classification principles described in tischendorf et al. (2007) the analysed micas are common true k micas. according to the occupancy of the octahedral layer, the analysed micas belong to the celadonite – muscovite series (fig. 6c) following the mgli-feal plot (mgli = mg – li; feal = (vifetot + mn + ti) vial, after; arbiol et al., 2021; tischendorf et al., 2007). also, the fe/al2o3 versus mg/al2o3 ratios of the analysed micas uniformly plot in the muscovite field (fig. 6d) (see arbiol et al., 2021). forty-nine emp analyses were performed on chloritoid grains. chemical mapping was performed on two selected chloritoid blasts and showed slight mg enrichment and mn depletion from the core towards the rim (fig. 7a; b). all grains show similar chemical compositions (tab. 3c). chloritoid is characterized table 3b. selected microprobe analyses of muscovite in the investigated chloritoid schist from medvednica mt. muscovite wt% 1-11 1-12 1-16 1-17 1-20 1-28 1-29 1-50 1-52 min max avr sio2 46.73 46.17 45.54 45.94 45.61 45.89 45.37 46.07 45.91 45.37 46.73 45.91 tio2 0.25 0.13 0.12 0.06 0.15 0.15 0.07 0.12 0.11 0.06 0.25 0.13 al2o3 34.79 34.76 34.89 35.30 34.72 34.98 35.12 35.15 35.44 34.72 35.44 35.02 feo 2.32 2.26 3.05 2.72 2.67 2.22 2.54 2.33 2.92 2.22 3.05 2.56 mno 0.00 0.00 0.03 0.01 0.01 0.00 0.00 0.00 0.01 0.00 0.03 0.01 mgo 0.47 0.59 0.45 0.46 0.49 0.54 0.40 0.55 0.44 0.40 0.59 0.49 cao 0.03 0.00 0.00 0.00 0.01 0.00 0.00 0.02 0.00 0.00 0.03 0.01 na2o 0.62 0.61 0.55 0.64 0.58 0.57 0.64 0.56 0.54 0.54 0.64 0.59 k2o 10.44 10.26 10.61 10.01 10.29 10.69 10.61 10.39 10.45 10.01 10.69 10.42 bao 0.13 0.05 0.18 0.15 0.21 0.14 0.15 0.12 0.11 0.05 0.21 0.14 h2o 4.51 4.48 4.46 4.49 4.45 4.47 4.44 4.49 4.50 4.44 4.51 4.48 total 100.29 99.30 99.89 99.78 99.18 99.66 99.34 99.80 100.44 si 3.11 3.10 3.06 3.07 3.08 3.08 3.06 3.08 3.06 3.06 3.11 3.08 ti 0.01 0.01 0.01 0.00 0.01 0.01 0.00 0.01 0.01 0.00 0.01 0.01 altot 2.73 2.75 2.77 2.78 2.76 2.77 2.79 2.77 2.79 2.73 2.79 2.77 aliv 0.89 0.90 0.94 0.93 0.92 0.92 0.94 0.92 0.94 0.89 0.94 0.92 alvi 1.84 1.85 1.83 1.86 1.84 1.85 1.85 1.85 1.85 1.83 1.86 1.84 fe+2 0.13 0.13 0.17 0.15 0.15 0.12 0.14 0.13 0.16 0.12 0.17 0.14 mn 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 mg 0.05 0.06 0.05 0.05 0.05 0.05 0.04 0.05 0.04 0.04 0.06 0.05 ca 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 na 0.08 0.08 0.07 0.08 0.08 0.07 0.08 0.07 0.07 0.07 0.08 0.08 k 0.89 0.88 0.91 0.85 0.89 0.92 0.91 0.89 0.89 0.85 0.92 0.89 ba 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 h 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 total 9.72 9.75 9.80 9.78 9.77 9.79 9.83 9.78 9.80 muscovite formulae calculated on basis of 11 oxygen atoms and all iron was considered as fe2+ g eo lo gi a c ro at ic a geologia croatica 76/122 ta bl e 3c . s el ec te d m ic ro pr ob e an al ys es o f c hl or ito id in th e in ve st ig at ed c hl or ito id sc hi st fr om m ed ve dn ic a m t. ch lo rit oi d rim rim rim rim co re co re co re co re rim rim rim rim rim rim rim rim w t% 11 13 14 15 16 17 18 19 110 114 121 132 133 134 135 136 137 138 139 140 141 149 151 153 242 250 si o 2 24 .1 0 24 .1 7 23 .9 3 23 .9 6 23 .8 0 23 .9 9 24 .1 3 24 .1 3 23 .9 9 23 .4 3 23 .7 6 23 .8 0 23 .9 9 23 .9 4 23 .8 0 24 .0 3 23 .8 9 24 .0 0 23 .9 8 24 .0 9 23 .9 6 24 .0 0 23 .8 2 24 .1 3 22 .8 9 23 .0 1 ti o 2 0. 02 0. 02 0. 00 0. 02 0. 00 0. 00 0. 01 0. 04 0. 17 0. 05 0. 00 0. 00 0. 00 0. 03 0. 00 0. 00 0. 02 0. 01 0. 01 0. 01 0. 03 0. 00 0. 55 0. 02 0. 00 0. 00 a l 2o 3 39 .3 5 39 .6 0 39 .6 3 39 .7 8 39 .0 9 39 .9 6 39 .8 0 39 .8 2 39 .8 0 39 .4 3 39 .0 8 39 .2 6 39 .5 4 39 .1 7 39 .2 3 39 .1 2 39 .4 3 39 .2 7 39 .4 8 39 .2 6 39 .5 4 39 .3 0 39 .4 0 40 .0 8 39 .5 5 39 .4 3 fe o 26 .1 4 26 .4 1 25 .7 8 25 .5 3 26 .5 5 25 .9 4 25 .8 5 26 .2 2 25 .6 0 24 .9 4 26 .5 9 25 .8 5 26 .0 2 26 .2 0 26 .4 0 26 .1 0 25 .8 0 25 .6 2 25 .6 8 25 .9 7 25 .7 9 25 .7 0 25 .0 8 25 .3 2 25 .0 6 25 .7 0 m no 0. 00 0. 34 0. 41 0. 41 0. 41 0. 38 0. 41 0. 28 0. 30 0. 44 0. 40 0. 35 0. 35 0. 44 0. 43 0. 38 0. 45 0. 42 0. 35 0. 39 0. 33 0. 33 0. 37 0. 34 0. 36 0. 32 m go 2. 69 2. 75 2. 77 2. 93 2. 71 2. 71 2. 99 2. 67 2. 75 2. 90 2. 66 2. 76 2. 85 2. 63 2. 66 2. 55 2. 66 2. 78 2. 75 2. 75 2. 79 2. 60 2. 85 2. 67 2. 69 2. 77 to ta l 92 .3 0 93 .2 9 92 .5 3 92 .6 2 92 .5 5 92 .9 8 93 .1 9 93 .1 5 92 .6 1 91 .1 8 92 .4 8 92 .0 2 92 .7 6 92 .4 0 92 .5 1 92 .1 9 92 .2 4 92 .1 0 92 .2 5 92 .4 6 92 .4 3 91 .9 2 92 .0 6 92 .5 5 90 .5 4 91 .2 4 a. p. f.u . si 2. 00 1. 99 1. 98 1. 98 1. 97 1. 98 1. 98 1. 98 1. 98 1. 96 1. 97 1. 98 1. 98 1. 99 1. 97 2. 00 1. 98 1. 99 1. 99 2. 00 1. 98 2. 00 1. 98 1. 99 1. 93 1. 93 ti 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 01 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 03 0. 00 0. 00 0. 00 a l 3. 85 3. 84 3. 87 3. 87 3. 82 3. 88 3. 85 3. 86 3. 88 3. 89 3. 82 3. 85 3. 85 3. 83 3. 84 3. 84 3. 86 3. 85 3. 86 3. 84 3. 86 3. 86 3. 86 3. 90 3. 94 3. 90 fe +2 1. 67 1. 65 1. 65 1. 63 1. 66 1. 67 1. 63 1. 66 1. 66 1. 64 1. 67 1. 65 1. 64 1. 66 1. 67 1. 66 1. 65 1. 63 1. 64 1. 64 1. 65 1. 65 1. 64 1. 65 1. 70 1. 70 fe +3 0. 15 0. 16 0. 13 0. 13 0. 18 0. 12 0. 15 0. 14 0. 11 0. 10 0. 18 0. 15 0. 15 0. 16 0. 16 0. 16 0. 14 0. 15 0. 14 0. 16 0. 14 0. 14 0. 11 0. 10 0. 06 0. 10 m n 0. 00 0. 02 0. 03 0. 03 0. 03 0. 03 0. 03 0. 02 0. 02 0. 03 0. 03 0. 02 0. 02 0. 03 0. 03 0. 03 0. 03 0. 03 0. 02 0. 03 0. 02 0. 02 0. 03 0. 02 0. 03 0. 02 m g 0. 33 0. 34 0. 34 0. 36 0. 34 0. 33 0. 37 0. 33 0. 34 0. 36 0. 33 0. 34 0. 35 0. 33 0. 33 0. 32 0. 33 0. 34 0. 34 0. 34 0. 34 0. 32 0. 35 0. 33 0. 34 0. 35 to ta l 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 xf e= fe /( fe +m g+ m n) 0. 85 0. 83 0. 83 0. 82 0. 83 0. 83 0. 82 0. 84 0. 83 0. 82 0. 84 0. 83 0. 83 0. 84 0. 84 0. 84 0. 83 0. 83 0. 83 0. 83 0. 83 0. 84 0. 82 0. 83 0. 83 0. 83 ch lo rit oi d fo rm ul ae c al cu la te d on b as is o f 1 2 ox yg en a to m s, iro n w as c al cu la te d as f e3+ =4 -(a l+ ti ) g eologia c roatica mišur et al.: petrochronological study of chloritoid schist from medvednica mountain (zagorje mid-transdanubian zone, croatia) 23 ta bl e 3c . ( co nt in ue d) . rim rim rim co re rim rim co re co re rim rim rim rim rim w t% 235 234 226 228 248 244 233 230 220 224 239 229 231 222 232 246 215 211 28 22 210 218 217 m in m ax av r si o 2 23 .0 6 23 .0 7 23 .1 1 23 .1 2 23 .1 8 23 .1 9 23 .3 0 23 .3 0 23 .3 9 23 .4 1 23 .4 6 23 .5 2 23 .5 4 23 .6 4 23 .7 2 23 .7 3 23 .8 5 23 .8 6 24 .0 1 24 .0 2 24 .1 2 24 .3 1 24 .4 6 22 .8 9 24 .4 6 23 .7 4 ti o 2 0. 02 0. 84 0. 01 0. 00 0. 01 0. 00 0. 01 0. 05 0. 00 0. 00 0. 02 0. 00 0. 02 0. 00 0. 02 0. 02 0. 02 0. 02 0. 05 0. 00 0. 00 0. 00 0. 08 0. 00 0. 84 0. 04 a l 2o 3 39 .8 3 38 .9 2 38 .9 9 38 .8 8 39 .7 4 39 .5 8 39 .6 3 39 .5 9 39 .1 3 39 .3 8 40 .4 1 38 .9 1 39 .1 6 39 .5 1 39 .6 9 39 .7 2 39 .6 2 39 .5 7 40 .5 5 39 .5 7 40 .6 2 39 .9 9 40 .4 4 38 .8 8 40 .6 2 39 .5 5 fe o 25 .5 6 25 .6 0 26 .0 5 25 .2 0 24 .3 6 24 .7 7 25 .6 4 25 .2 6 25 .8 4 25 .2 3 24 .7 0 25 .9 4 26 .0 6 25 .1 3 25 .2 0 25 .0 6 26 .1 0 25 .4 5 24 .6 3 25 .2 2 25 .0 3 25 .3 9 25 .0 8 24 .3 6 26 .5 9 25 .6 0 m no 0. 36 0. 35 0. 35 0. 38 0. 38 0. 35 0. 45 0. 38 0. 34 0. 35 0. 41 0. 35 0. 52 0. 37 0. 51 0. 46 0. 33 0. 31 0. 36 0. 37 0. 42 0. 39 0. 41 0. 00 0. 52 0. 37 m go 2. 66 2. 76 2. 64 2. 70 3. 05 2. 85 2. 75 2. 93 2. 76 2. 73 2. 82 2. 67 2. 79 2. 92 2. 64 2. 67 2. 69 2. 67 2. 78 2. 63 2. 77 2. 89 2. 65 2. 55 3. 05 2. 75 to ta l 91 .4 8 91 .5 3 91 .1 5 90 .2 8 90 .7 2 90 .7 5 91 .7 8 91 .5 2 91 .4 5 91 .1 1 91 .8 3 91 .4 0 92 .1 0 91 .5 8 91 .7 8 91 .6 6 92 .6 1 91 .8 8 92 .3 7 91 .8 0 92 .9 7 92 .9 7 93 .1 2 a. p. f.u . si 1. 93 1. 94 1. 94 1. 96 1. 95 1. 95 1. 94 1. 95 1. 96 1. 97 1. 95 1. 97 1. 96 1. 97 1. 98 1. 98 1. 97 1. 99 1. 98 2. 00 1. 98 2. 00 2. 01 1. 93 2. 01 1. 97 ti 0. 00 0. 05 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 00 0. 05 0. 00 a l 3. 93 3. 85 3. 87 3. 89 3. 93 3. 92 3. 90 3. 90 3. 86 3. 90 3. 96 3. 85 3. 84 3. 88 3. 90 3. 91 3. 86 3. 88 3. 95 3. 89 3. 93 3. 87 3. 91 3. 82 3. 96 3. 88 fe +2 1. 71 1. 70 1. 70 1. 67 1. 64 1. 67 1. 68 1. 66 1. 67 1. 67 1. 67 1. 67 1. 66 1. 64 1. 66 1. 66 1. 67 1. 66 1. 65 1. 65 1. 65 1. 62 1. 64 1. 62 1. 71 1. 66 fe +3 0. 07 0. 10 0. 13 0. 11 0. 07 0. 08 0. 10 0. 10 0. 14 0. 10 0. 04 0. 15 0. 16 0. 12 0. 10 0. 09 0. 14 0. 11 0. 05 0. 11 0. 07 0. 13 0. 08 0. 04 0. 18 0. 12 m n 0. 03 0. 02 0. 03 0. 03 0. 03 0. 03 0. 03 0. 03 0. 02 0. 02 0. 03 0. 03 0. 04 0. 03 0. 04 0. 03 0. 02 0. 02 0. 02 0. 03 0. 03 0. 03 0. 03 0. 00 0. 04 0. 03 m g 0. 33 0. 34 0. 33 0. 34 0. 38 0. 36 0. 34 0. 36 0. 34 0. 34 0. 35 0. 33 0. 35 0. 36 0. 33 0. 33 0. 33 0. 33 0. 34 0. 33 0. 34 0. 35 0. 32 0. 32 0. 38 0. 34 to ta l 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 8. 00 xf e= fe /( fe +m g+ m n) 0. 83 0. 83 0. 84 0. 83 0. 81 0. 82 0. 83 0. 82 0. 83 0. 83 0. 82 0. 84 0. 83 0. 82 0. 83 0. 83 0. 84 0. 83 0. 82 0. 83 0. 82 0. 82 0. 83 ch lo rit oi d fo rm ul ae c al cu la te d on b as is o f 1 2 ox yg en a to m s, iro n w as c al cu la te d as f e3+ =4 -(a l+ ti ) g eo lo gi a c ro at ic a geologia croatica 76/124 by fe3+ = 0.04 – 0.18 apfu, fe2+ = 1.62 – 1.71 apfu, mn = 0.00 – 0.04 apfu, and mg = 0.32 – 0.38 apfu based on calculations with 12 oxygen and 8 cations (without h2o). 4.4. chemistry and age of monazite the emp chemical dating data on monazite are presented in table 4 and figure 8. the structural calculations are based on 16 oxygen atoms. the examined monazites are characterized by the irregular grain shapes of lobate, amoeboid and elongated contours (fig. 8a; b). results of 30 analyses show a range of values for ce2o3 (34.1 – 22.7 wt%), la2o3 (15.3 – 4.6 wt%) and y2o3 (0.3 – 1.6 wt%). the tho2 contents vary from 1.56 to 5.89 wt.%. low sio2 (0.17 – 0.82 wt.%) contents and slightly elevated cao (0.45 – 1.1 wt.%) contents characterize the analysed monazite (tab. 4). concentrations of th, u, and total pb in 30 analyses were used for chemical age calculations, including uncertainties, utilizing the method as described in montel et al. (1996) and suzuki & kato (2008) (fig. 9a). monazite (mnz) analyses are marked using the first symbol to indicate the grain and the second one (after the slash) the number of the analysis. four analyses (mnz 2/1: 219 ± 19 ma; mnz c/1: 211 ± 18 ma; mnz 3/1x: 192.50 ± 16.70 ma and mnz i/1: 93 ± 8 ma) were rejected from the weighted mean as outliers by the generalized chauvenet criterion (chauvenet, 1863; empty boxes on fig. 9a). based on the crystal chemical composition (see below) the calculated ages from the remaining 26 measurements are separated into two age groups. the calculated weighted mean of 13 measurements of the younger monazite group is 142.95 ± 1.72 ma with an mswd value of 1.27. the calculated weighted mean age for the 13 measurements yielding older ages is 167.54 ± 2.01 with an mswd of 0.45 (tab. 4, fig. 9a). the two corresponding ages (143.0 and 167.5 ma) are visible as plateaus on the weighted mean diagram in figure 9a. the clustering of ages is compatible with the zonation that was observed in monazite grains on sem-bse images (fig. 8b). monazite grain mnz 6 with 7 analyses shows an age distribution split into two groups: (1) younger mnz 6/1x, mnz 6/2, mnz 6/3 and mnz 6/7 rim analyses with an average of 143 ± 6.2 ma and mswd of 0.38 and (2) older mnz 6/5, mnz 6/4 and mnz 6/1 core analyses with an average of 170 ± 8.5 ma, mswd of 0.024 (fig. 8b). the concentrations of heavy rees (hrees) in monazite of the younger age cluster (n=13) are lower than in the older monazite (n=13) as shown in figure 9b. in the triangular plot of lree2o3, (hree2o3+y2o3)10 and (tho2+uo2)20, the younger and older monazite age data can be discriminated (fig. 9c, after andersson et al., 2018; pyle et al., 2001). in the diagram 4(th+u+pb) vs. 4(ree+y+p), the measured monazites follow the cheralite substitution (ca(th,u)ree-2) rather than the huttonite ((th, u)siree-1p-1) exchange vector (pyle et al., 2001; ondrejka et al., 2012)(fig. 9d) with subordinate amounts of cheralite (4 – 9 wt.%) and huttonite (up to 2 wt.%) calculated according to pyle et al. (2001), (tab. 4). 4.5. chloritoid-schist geothermobarometry to correctly apply the geothermobarometers outlined in section 3.4.1., spots were chosen for the chemical analyses of chlorite, chloritoid and muscovite based on microtextural evaluation of mineral equilibrium using bse images (fig. 10). for classical thermometry 10 chlorite chloritoid pairs were analysed. these pairs were selected based on the criterion given by vidal et al. (1999), the main criterion being the achievement and preservation of textural and chemical equilibrium of chloritoid and chlofigure 5. chlorite classification diagrams for chloritoid schist, sample st-6 (in red circles), from medvednica mt. a) octahedral fe/(fe + mg) versus tetrahedral al diagram with different classes of fe-mg chlorite (classification after foster, 1962; clinochlore-chamosite boundary (vertical dashed line) after bailey, 1980; chlorite polytype area in grey colour after foster, 1962. b) compositional fields of chlorite (after zane & weiss, 1998). type i chlorite is dominantly mg-fe chlorite, depending on the dominant cation. type ii chlorite is dominantly al-chlorite. c) fe + mg – si – al(total) ternary diagram (after abd elmola et al., 2017). g eologia c roatica mišur et al.: petrochronological study of chloritoid schist from medvednica mountain (zagorje mid-transdanubian zone, croatia) 25 rite grains. with that in mind, nearest neighbours were selected and measured close to the rim (fig. 10). the temperatures obtained with the fe2+ mg exchange geothermometer, range between 527 and 568 °c (fig. 10, tab. 5). the application of the chlorite thermometry after inoue et al. (2018) yielded temperatures between 250 and 598 °c, calculated for 14 selected chlorite grains, which were not in contact with chloritoid grains. this temperature range might indicate that some analysed chlorites did not equilibrate with chloritoid (fig. 10, tab. 5). the nine white mica compositions were used to estimate pressure, resulting in 0.87 to 0.99 gpa at a temperature of 550 °c using the caddick & thompson (2008) formulation. this temperature resulted from the previously applied geothermometers. a change of the input temperature by ± 50 °c leads to a pressure change of about ± 0.08 gpa (see tab. 5). the p-t pseudosection modelling in the mnnckfmashto system with 0, 5, 10, 15, and 20 % fe as fe2o3 at water saturation with perple_x led to different p-t conditions by using the relevant mineral compositions (section 4.3.) of chloritoid (xfe = 0.81 – 0.85), chlorite (xfe = 0.51 – 0.58) and muscovite (3.06 – 3.11 si apfu) (supplementary 1). for example, at 550 °c (tab. 5), the si content (3.07 apfu) in muscovite points to 0.9 gpa in the calculation with 0 % fe as fe2o3 but to 1.05 gpa with 20 % fe as fe2o3. 5. discussion 5.1. protolith considering the field relationships, the petrographical analyses and geochemical analyses, the investigated samples are metamorphosed sediments, originally siltstones and sandstones. diagenesis and low-grade metamorphism can affect the chemical composition of the source sediments, but the rees, th, sc, and other semimobile to immobile trace elements are usually not affected by these processes and are, thus, useful for comprehending the source rocks (bhatia & crook, 1986; mclennan & taylor, 1991; cullers, 2002; balen et al., 2013). high values figure 6. white mica classification diagrams for chloritoid schist from medvednica mt., sample st-6 (in red circles). a) interlayer k – na – ca triangular plot (arbiol et al., 2021). b) al vs. fe + mg + si (apfu) binary diagram with scales of tschermak substitution of the mica. c) mgli/feal diagram with mica end-members, ideal endmembers, and a theoretical component. prefixes characterize varieties of the muscovite-celadonite series (mgli = mg – li; feal = (vifetot + mn + ti)-vial, after; arbiol et al., 2021; tischendorf et al., 2007). (d) feo/al2o3 vs. mgo/al2o3 binary diagram (after arbiol et al., 2021, and reference therein). g eo lo gi a c ro at ic a geologia croatica 76/126 for the ratios la/sc (1.85 – 5.43), th/sc (0.68 – 2.83), la/co (1.20 – 7.41), and th/co (0.36 – 3.86) in the studied samples are indicative of dominantly felsic rock compositions in the source area of the protoliths of the studied metasediments (bhatia & crook, 1986; cullers, 1994a,b; 2000) (tab. 2). the la/th versus hf diagram (after floyd & leveridge, 1987) also indicates acidic arc rocks and a passive continental margin as a possible source for these protoliths (fig. 11). comparable conclusions can be drawn from the curves with similar tendencies of hree depletion on the spider diagram of ree concentrations in the studied rocks (normalized to chondrite, boynton, 1984) (fig. 4). siliciclastic sediments coming from the mature continental crust are usually characterized by lree enrichment and reasonably high and flat hree values (cullers, 1994b; balen et al., 2013), which can be also seen in our samples (fig. 4). in addition, pronounced negative eu anomalies (eu/eu*) ranging between 0.65 and 0.78 are consistent with those for siliciclastic sediments from felsic/granitoid sources (cullers, 2000, figure 7. chemical maps of two analysed chloritoids from medvednica mt. (sample st-6). a) xmg distribution map obtained from a chloritoid grain with the emp. the measuring pattern is marked in red. on the right is the associated diagram of the measured profile with xmg values across the chloritoid grain. b) sem image of chloritoid grain with marked emp measuring pattern, and associated diagram of the measured profile with xmg values across the chloritoid grain, on the right. figure 8. a) sem-bse image of objects in sample st-6 with marked positions of the monazite grains, between the yellow lines is a cleavage domain (s1) composed of white mica and occasional metamorphic monazite (wm – white mica, ctdchloritoid, q-quartz). b) sem images of measured monazite grains with marked locations of the measurement spots (in red ellipse) and corresponding age data in white. g eologia c roatica mišur et al.: petrochronological study of chloritoid schist from medvednica mountain (zagorje mid-transdanubian zone, croatia) 27 2002). the contents of trace elements in our rocks show similar patterns and agree well with the composition of the upper continental crust (mclennan, 2001) (fig. 4). according to the geochemical features of the studied schists (tab. 2; fig. 4), the detritus for their protoliths is predominantly upper crustal material with felsic rocks dominating in the source area. similar conclusions can be drawn from analyses of metasediments from medvednica mt. by mišur et al. (2013; 2015). the authors analysed a sample of chloritoid schist (d7 in table 2) from the same locali ty as in this study but taken from a lower position of the outcrop. the difference in ree contents between the here studied sample st-6 and sample d7 is minor (fig. 4) and can be prescribed to common variations of similar metasediments within an outcrop. based on lithological analogy, the age of detrital zircons and palaeontological analyzes of the surrounding rocks, the chloritoid schist protolith sediment was deposited during the upper permian -lower triassic or younger (đurđanović, 1973; belak 2005; mišur, 2017; belak et al., 2022). figure 9. a) diagram presenting the weighted mean of the two age groups determined on monazite, 142.95 ma (n=13, in red) and 167.57 ma (n=13, in blue), four measurements were excluded as outliers (transparent rectangles). b) chondrite ree pattern from monazite, sample st-6 (ree in chondrite after boynton, 1984). c) triangular lree2o3 – (tho2+uo2)20 – (hree2o3+y2o3)10 plot of monazite composition from sample st-6, younger monazites (in red) and older monazite (in blue), trend lines are in the same colours (after andersson et al., 2018; spear & pyle, 2002). d) diagram 4(th+u+pb) vs. 4(ree+y+p) with exchange vectors; cheralite (ca(th, u)ree-2) in opposite to huttonite ((th, u)siree-1p-1) for a sample of chloritoid schist (st-6) medvednica mt. (after pyle et al., 2001; ondrejka et al., 2012). g eo lo gi a c ro at ic a geologia croatica 76/128 table 4. representative electron microprobe analyses of monazite composition, u, th, pb, ree and calculated forming ages, from chloritoid schist st-6 (medvednica mt.). the structural formulae are calculated based on 16 oxygen atoms (in atoms per formula unit, apfu). calculated ages (at the bottom) and selected chemical data (rees, y, th, u, pb normalized to chondrite after boynton, 1984). the younger monazite age group is highlighted in pale grey; dark grey refers to the older monazite group. monazite mnz i/1 mnz 3/4 mnz b/2 mnz 5/1 mnz 6/2 mnz 6/3 mnz 6/7 mnz b/1 mnz e/7 mnz 6/1x mnz 8/3 mnz 3/5 mnz 3/2 mnz 4/1 mnz 3/2x monazite mnz e/1 mnz 1/2 mnz e/6 mnz 6/5 mnz f/1 mnz 8/1 mnz 6/4 mnz 1/3 mnz 3/1 mnz b/3 mnz 6/1 mnz 3/6 mnz 3/1x mnz c/1 mnz 2/1 sio2 0.29 0.48 0.29 0.37 0.67 0.37 0.25 0.29 0.34 0.61 0.66 0.74 0.52 0.31 0.40 sio2 0.36 0.43 0.51 0.37 0.27 0.43 0.39 0.17 0.48 0.35 0.37 0.82 0.26 0.29 0.47 p2o5 29.05 27.23 28.71 28.00 27.41 27.75 27.92 28.40 28.99 27.40 27.28 27.04 27.70 28.46 28.03 p2o5 28.75 27.69 28.80 27.70 28.90 28.79 27.72 28.07 27.50 28.72 27.61 26.68 27.81 28.94 27.40 as2o5 0.02 0.00 0.00 0.00 0.02 0.07 0.00 0.05 0.01 0.02 0.01 0.00 0.00 0.00 0.00 as2o5 0.00 0.00 0.00 0.07 0.00 0.03 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 pbo 0.01 0.03 0.02 0.03 0.04 0.02 0.02 0.02 0.02 0.04 0.03 0.03 0.03 0.02 0.02 pbo 0.02 0.03 0.02 0.02 0.01 0.03 0.03 0.02 0.04 0.02 0.02 0.05 0.03 0.03 0.03 tho2 2.18 4.58 3.21 4.52 5.89 3.78 2.76 2.87 2.86 5.67 4.98 4.55 4.98 2.72 2.84 tho2 2.73 3.85 2.77 3.20 1.56 3.73 3.99 2.29 4.80 3.16 2.71 5.78 3.46 2.80 2.98 uo2 0.02 0.05 0.03 0.07 0.05 0.03 0.03 0.04 0.03 0.04 0.06 0.04 0.05 0.04 0.04 uo2 0.03 0.03 0.06 0.04 0.03 0.04 0.04 0.03 0.05 0.03 0.08 0.04 0.04 0.04 0.03 y2o3 0.45 0.66 0.59 0.65 0.85 0.83 0.54 0.57 0.56 0.67 0.64 0.55 0.68 1.62 0.37 y2o3 0.62 0.61 0.42 0.69 0.43 0.66 0.64 0.53 0.66 0.35 0.46 0.60 0.35 0.55 0.30 la2o3 13.17 11.88 12.54 13.02 4.60 4.96 9.99 12.65 14.56 8.21 11.09 13.45 11.86 9.59 14.17 la2o3 14.99 12.84 15.00 11.62 13.69 11.57 11.38 15.29 11.78 13.56 12.14 10.60 15.08 13.47 13.28 ce2o3 31.06 32.12 29.17 29.67 22.67 23.61 32.03 30.21 33.41 29.73 31.81 30.56 31.86 31.61 31.13 ce2o3 31.76 32.54 30.55 32.36 31.65 32.38 32.23 34.08 31.79 31.50 29.36 30.69 31.37 32.54 31.24 pr2o3 3.32 3.53 3.31 3.35 4.08 4.16 3.83 3.32 3.24 3.85 3.57 3.29 3.50 3.94 3.27 pr2o3 3.38 3.51 3.31 3.71 3.47 3.59 3.76 3.35 3.48 3.38 3.40 3.61 3.18 3.43 3.56 nd2o3 12.45 13.40 13.72 13.15 20.37 21.23 15.57 13.54 11.77 16.04 13.49 13.08 13.31 15.45 12.16 nd2o3 12.62 12.75 12.99 14.22 13.21 13.93 14.29 11.43 13.24 12.96 13.84 13.78 11.59 12.69 13.28 sm2o3 2.58 2.20 3.25 2.54 6.15 6.36 2.85 3.10 1.95 3.07 2.29 2.25 2.21 2.64 2.16 sm2o3 2.34 2.14 2.64 2.26 2.86 2.33 2.39 1.71 2.17 2.69 2.93 2.34 2.03 2.27 2.59 eu2o3 0.57 0.36 0.72 0.55 1.00 0.95 0.46 0.69 0.28 0.53 0.30 0.33 0.32 0.46 0.45 eu2o3 0.35 0.34 0.51 0.33 0.58 0.38 0.34 0.26 0.31 0.51 0.57 0.37 0.37 0.35 0.45 gd2o3 3.90 0.92 4.91 1.51 3.17 3.03 1.76 4.73 3.74 1.85 0.78 1.22 0.89 1.49 1.46 gd2o3 3.84 0.92 4.30 1.02 4.50 0.95 1.11 0.71 0.93 4.34 1.97 1.18 1.34 3.74 1.71 tb2o3 0.05 0.00 0.12 0.12 0.11 0.12 0.07 0.10 0.02 0.11 0.05 0.08 0.05 0.08 0.09 tb2o3 0.03 0.01 0.06 0.06 0.05 0.06 0.07 0.00 0.06 0.09 0.15 0.09 0.07 0.02 0.06 dy2o3 0.24 0.22 0.40 0.39 0.51 0.48 0.34 0.38 0.16 0.31 0.17 0.23 0.22 0.29 0.21 dy2o3 0.22 0.11 0.18 0.26 0.31 0.15 0.30 0.12 0.23 0.20 0.38 0.32 0.18 0.20 0.31 ho2o3 0.06 0.00 0.00 0.00 0.04 0.05 0.00 0.00 0.01 0.06 0.08 0.03 0.05 0.04 0.00 ho2o3 0.01 0.00 0.05 0.01 0.00 0.00 0.00 0.00 0.03 0.00 0.00 0.00 0.02 0.02 0.05 er2o3 0.39 0.31 0.41 0.33 0.34 0.30 0.32 0.37 0.40 0.32 0.33 0.31 0.38 0.30 0.30 er2o3 0.43 0.34 0.39 0.33 0.38 0.34 0.35 0.31 0.36 0.39 0.29 0.30 0.32 0.40 0.34 tm2o3 0.34 0.09 0.40 0.10 0.13 0.03 0.11 0.40 0.25 0.12 0.08 0.08 0.08 0.08 0.11 tm2o3 0.36 0.04 0.32 0.12 0.36 0.06 0.14 0.05 0.08 0.39 0.07 0.09 0.06 0.34 0.06 yb2o3 0.13 0.08 0.12 0.17 0.14 0.16 0.14 0.14 0.12 0.13 0.15 0.13 0.13 0.18 0.11 yb2o3 0.11 0.10 0.14 0.15 0.13 0.08 0.16 0.08 0.11 0.17 0.13 0.10 0.12 0.12 0.15 lu2o3 0.07 0.05 0.15 0.07 0.10 0.05 0.04 0.13 0.20 0.08 0.05 0.09 0.14 0.12 0.09 lu2o3 0.12 0.02 0.03 0.06 0.10 0.09 0.08 0.10 0.12 0.08 0.05 0.10 0.12 0.16 0.12 feo 0.05 0.60 0.07 0.88 0.07 0.04 0.09 0.13 0.06 0.10 0.51 0.58 0.55 0.03 0.04 feo 0.00 0.50 0.02 0.10 0.62 0.41 0.18 0.48 0.61 0.10 0.16 0.50 0.00 0.69 0.26 so3 0.12 0.68 0.16 0.09 0.10 0.25 0.19 0.13 0.22 0.09 0.10 0.05 0.12 0.11 0.26 so3 0.04 0.09 0.11 0.13 0.48 0.10 0.10 0.35 0.13 0.10 0.36 0.07 0.28 0.18 0.62 cao 0.53 1.10 0.84 0.98 0.99 0.98 0.73 0.68 0.75 0.83 0.77 0.60 0.80 0.65 0.86 cao 0.45 0.57 0.58 0.63 0.84 0.64 0.68 0.76 0.82 0.60 0.88 0.68 0.91 0.77 1.09 sro 0.10 0.42 0.12 0.17 0.07 0.06 0.08 0.13 0.10 0.07 0.06 0.03 0.07 0.05 0.16 sro 0.04 0.05 0.07 0.05 0.19 0.06 0.06 0.09 0.08 0.08 0.20 0.05 0.16 0.08 0.44 al2o3 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 al2o3 0.00 0.01 0.01 0.00 0.02 0.00 0.00 0.00 0.00 0.00 0.04 0.00 0.00 0.00 0.02 total 101.18 100.97 103.28 100.71 99.55 99.67 100.09 103.08 104.05 99.95 99.30 99.34 100.50 100.25 98.72 total 103.61 99.49 103.83 99.50 104.66 100.83 100.43 100.27 99.85 103.77 98.16 98.82 99.13 104.09 100.82 si 0.05 0.08 0.04 0.06 0.11 0.06 0.04 0.05 0.05 0.10 0.11 0.12 0.08 0.05 0.06 si 0.06 0.07 0.08 0.06 0.04 0.07 0.06 0.03 0.08 0.05 0.06 0.14 0.04 0.04 0.07 p 3.88 3.68 3.81 3.79 3.78 3.80 3.81 3.79 3.80 3.77 3.76 3.74 3.77 3.84 3.83 p 3.81 3.80 3.80 3.80 3.76 3.85 3.79 3.80 3.77 3.81 3.80 3.72 3.81 3.80 3.71 as 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 as 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 pb 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 pb 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 th 0.08 0.17 0.11 0.16 0.22 0.14 0.10 0.10 0.10 0.21 0.18 0.17 0.18 0.10 0.10 th 0.10 0.14 0.10 0.12 0.05 0.13 0.15 0.08 0.18 0.11 0.10 0.22 0.13 0.10 0.11 u 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 u 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 y 0.04 0.06 0.05 0.05 0.07 0.07 0.05 0.05 0.05 0.06 0.06 0.05 0.06 0.14 0.03 y 0.05 0.05 0.03 0.06 0.03 0.06 0.05 0.04 0.06 0.03 0.04 0.05 0.03 0.05 0.03 la 0.77 0.70 0.73 0.77 0.28 0.30 0.59 0.74 0.83 0.49 0.67 0.81 0.70 0.56 0.84 la 0.87 0.77 0.86 0.69 0.78 0.67 0.68 0.90 0.70 0.78 0.73 0.64 0.90 0.77 0.78 ce 1.79 1.88 1.67 1.74 1.35 1.40 1.89 1.74 1.90 1.77 1.90 1.83 1.88 1.85 1.84 ce 1.82 1.93 1.74 1.92 1.78 1.87 1.90 1.99 1.88 1.80 1.75 1.85 1.86 1.85 1.83 pr 0.19 0.21 0.19 0.20 0.24 0.25 0.23 0.19 0.18 0.23 0.21 0.20 0.21 0.23 0.19 pr 0.19 0.21 0.19 0.22 0.19 0.21 0.22 0.20 0.21 0.19 0.20 0.22 0.19 0.19 0.21 nd 0.70 0.76 0.77 0.75 1.18 1.23 0.90 0.76 0.65 0.93 0.78 0.76 0.76 0.88 0.70 nd 0.71 0.74 0.72 0.82 0.73 0.79 0.82 0.65 0.77 0.72 0.80 0.81 0.67 0.70 0.76 sm 0.14 0.12 0.18 0.14 0.35 0.36 0.16 0.17 0.10 0.17 0.13 0.13 0.12 0.15 0.12 sm 0.13 0.12 0.14 0.13 0.15 0.13 0.13 0.09 0.12 0.15 0.16 0.13 0.11 0.12 0.14 eu 0.03 0.02 0.04 0.03 0.06 0.05 0.03 0.04 0.01 0.03 0.02 0.02 0.02 0.03 0.02 eu 0.02 0.02 0.03 0.02 0.03 0.02 0.02 0.01 0.02 0.03 0.03 0.02 0.02 0.02 0.02 gd 0.20 0.05 0.26 0.08 0.17 0.16 0.09 0.25 0.19 0.10 0.04 0.07 0.05 0.08 0.08 gd 0.20 0.05 0.22 0.05 0.23 0.05 0.06 0.04 0.05 0.23 0.11 0.06 0.07 0.19 0.09 tb 0.00 0.00 0.01 0.01 0.01 0.01 0.00 0.01 0.00 0.01 0.00 0.00 0.00 0.00 0.00 tb 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 dy 0.01 0.01 0.02 0.02 0.03 0.03 0.02 0.02 0.01 0.02 0.01 0.01 0.01 0.01 0.01 dy 0.01 0.01 0.01 0.01 0.02 0.01 0.02 0.01 0.01 0.01 0.02 0.02 0.01 0.01 0.02 ho 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ho 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 er 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 er 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.01 0.02 0.02 0.02 0.02 tm 0.02 0.00 0.02 0.01 0.01 0.00 0.01 0.02 0.01 0.01 0.00 0.00 0.00 0.00 0.01 tm 0.02 0.00 0.02 0.01 0.02 0.00 0.01 0.00 0.00 0.02 0.00 0.00 0.00 0.02 0.00 yb 0.01 0.00 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 yb 0.01 0.00 0.01 0.01 0.01 0.00 0.01 0.00 0.01 0.01 0.01 0.00 0.01 0.01 0.01 lu 0.00 0.00 0.01 0.00 0.01 0.00 0.00 0.01 0.01 0.00 0.00 0.00 0.01 0.01 0.00 lu 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.01 0.01 0.01 0.01 fe2+ 0.01 0.08 0.01 0.12 0.01 0.01 0.01 0.02 0.01 0.01 0.07 0.08 0.07 0.00 0.01 fe2+ 0.00 0.07 0.00 0.01 0.08 0.05 0.02 0.06 0.08 0.01 0.02 0.07 0.00 0.09 0.03 s 0.01 0.08 0.02 0.01 0.01 0.03 0.02 0.02 0.03 0.01 0.01 0.01 0.01 0.01 0.03 s 0.01 0.01 0.01 0.02 0.06 0.01 0.01 0.04 0.02 0.01 0.04 0.01 0.03 0.02 0.07 ca 0.09 0.19 0.14 0.17 0.17 0.17 0.13 0.11 0.13 0.14 0.13 0.10 0.14 0.11 0.15 ca 0.07 0.10 0.10 0.11 0.14 0.11 0.12 0.13 0.14 0.10 0.15 0.12 0.16 0.13 0.19 sr 0.01 0.04 0.01 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.00 0.01 0.00 0.01 sr 0.00 0.00 0.01 0.00 0.02 0.01 0.01 0.01 0.01 0.01 0.02 0.00 0.01 0.01 0.04 al 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 al 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 x(cheralite) 0.04 0.09 0.07 0.08 0.08 0.08 0.06 0.06 0.06 0.07 0.06 0.05 0.07 0.05 0.07 x(cheralite) 0.04 0.05 0.05 0.05 0.07 0.05 0.06 0.06 0.07 0.05 0.08 0.06 0.08 0.06 0.09 x(huttonite) 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.02 0.01 0.02 0.01 0.00 0.00 x(huttonite) 0.01 0.01 0.00 0.00 0.00 0.01 0.01 0.00 0.01 0.00 0.00 0.02 0.00 0.00 0.00 x(monazite) 0.96 0.91 0.94 0.92 0.90 0.92 0.95 0.95 0.95 0.91 0.92 0.93 0.92 0.95 0.94 x(monazite) 0.96 0.94 0.95 0.94 0.95 0.94 0.94 0.95 0.92 0.95 0.94 0.92 0.93 0.94 0.93 sum kat. 8.06 8.15 8.11 8.15 8.09 8.09 8.10 8.12 8.10 8.09 8.12 8.13 8.12 8.08 8.08 sum kat. 8.10 8.11 8.10 8.10 8.15 8.07 8.11 8.12 8.13 8.10 8.10 8.12 8.09 8.14 8.15 age (ma) 93.30 132.50 132.80 135.10 140.10 142.50 144.40 145.00 145.50 145.60 146.80 149.20 152.80 154.10 159.60 age (ma) 160.60 162.70 164.10 168.80 168.80 168.90 169.30 169.50 169.70 169.70 173.00 176.80 192.50 211.00 219.40 2 sd 8.10 11.50 11.50 11.70 12.10 12.30 12.50 12.60 12.60 12.60 12.70 12.90 13.20 13.30 13.80 2 sd 13.90 14.10 14.20 14.60 14.60 14.60 14.70 14.70 14.70 14.70 15.00 15.30 16.70 18.30 19.00 g eologia c roatica mišur et al.: petrochronological study of chloritoid schist from medvednica mountain (zagorje mid-transdanubian zone, croatia) 29 table 4. representative electron microprobe analyses of monazite composition, u, th, pb, ree and calculated forming ages, from chloritoid schist st-6 (medvednica mt.). the structural formulae are calculated based on 16 oxygen atoms (in atoms per formula unit, apfu). calculated ages (at the bottom) and selected chemical data (rees, y, th, u, pb normalized to chondrite after boynton, 1984). the younger monazite age group is highlighted in pale grey; dark grey refers to the older monazite group. monazite mnz i/1 mnz 3/4 mnz b/2 mnz 5/1 mnz 6/2 mnz 6/3 mnz 6/7 mnz b/1 mnz e/7 mnz 6/1x mnz 8/3 mnz 3/5 mnz 3/2 mnz 4/1 mnz 3/2x monazite mnz e/1 mnz 1/2 mnz e/6 mnz 6/5 mnz f/1 mnz 8/1 mnz 6/4 mnz 1/3 mnz 3/1 mnz b/3 mnz 6/1 mnz 3/6 mnz 3/1x mnz c/1 mnz 2/1 sio2 0.29 0.48 0.29 0.37 0.67 0.37 0.25 0.29 0.34 0.61 0.66 0.74 0.52 0.31 0.40 sio2 0.36 0.43 0.51 0.37 0.27 0.43 0.39 0.17 0.48 0.35 0.37 0.82 0.26 0.29 0.47 p2o5 29.05 27.23 28.71 28.00 27.41 27.75 27.92 28.40 28.99 27.40 27.28 27.04 27.70 28.46 28.03 p2o5 28.75 27.69 28.80 27.70 28.90 28.79 27.72 28.07 27.50 28.72 27.61 26.68 27.81 28.94 27.40 as2o5 0.02 0.00 0.00 0.00 0.02 0.07 0.00 0.05 0.01 0.02 0.01 0.00 0.00 0.00 0.00 as2o5 0.00 0.00 0.00 0.07 0.00 0.03 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 pbo 0.01 0.03 0.02 0.03 0.04 0.02 0.02 0.02 0.02 0.04 0.03 0.03 0.03 0.02 0.02 pbo 0.02 0.03 0.02 0.02 0.01 0.03 0.03 0.02 0.04 0.02 0.02 0.05 0.03 0.03 0.03 tho2 2.18 4.58 3.21 4.52 5.89 3.78 2.76 2.87 2.86 5.67 4.98 4.55 4.98 2.72 2.84 tho2 2.73 3.85 2.77 3.20 1.56 3.73 3.99 2.29 4.80 3.16 2.71 5.78 3.46 2.80 2.98 uo2 0.02 0.05 0.03 0.07 0.05 0.03 0.03 0.04 0.03 0.04 0.06 0.04 0.05 0.04 0.04 uo2 0.03 0.03 0.06 0.04 0.03 0.04 0.04 0.03 0.05 0.03 0.08 0.04 0.04 0.04 0.03 y2o3 0.45 0.66 0.59 0.65 0.85 0.83 0.54 0.57 0.56 0.67 0.64 0.55 0.68 1.62 0.37 y2o3 0.62 0.61 0.42 0.69 0.43 0.66 0.64 0.53 0.66 0.35 0.46 0.60 0.35 0.55 0.30 la2o3 13.17 11.88 12.54 13.02 4.60 4.96 9.99 12.65 14.56 8.21 11.09 13.45 11.86 9.59 14.17 la2o3 14.99 12.84 15.00 11.62 13.69 11.57 11.38 15.29 11.78 13.56 12.14 10.60 15.08 13.47 13.28 ce2o3 31.06 32.12 29.17 29.67 22.67 23.61 32.03 30.21 33.41 29.73 31.81 30.56 31.86 31.61 31.13 ce2o3 31.76 32.54 30.55 32.36 31.65 32.38 32.23 34.08 31.79 31.50 29.36 30.69 31.37 32.54 31.24 pr2o3 3.32 3.53 3.31 3.35 4.08 4.16 3.83 3.32 3.24 3.85 3.57 3.29 3.50 3.94 3.27 pr2o3 3.38 3.51 3.31 3.71 3.47 3.59 3.76 3.35 3.48 3.38 3.40 3.61 3.18 3.43 3.56 nd2o3 12.45 13.40 13.72 13.15 20.37 21.23 15.57 13.54 11.77 16.04 13.49 13.08 13.31 15.45 12.16 nd2o3 12.62 12.75 12.99 14.22 13.21 13.93 14.29 11.43 13.24 12.96 13.84 13.78 11.59 12.69 13.28 sm2o3 2.58 2.20 3.25 2.54 6.15 6.36 2.85 3.10 1.95 3.07 2.29 2.25 2.21 2.64 2.16 sm2o3 2.34 2.14 2.64 2.26 2.86 2.33 2.39 1.71 2.17 2.69 2.93 2.34 2.03 2.27 2.59 eu2o3 0.57 0.36 0.72 0.55 1.00 0.95 0.46 0.69 0.28 0.53 0.30 0.33 0.32 0.46 0.45 eu2o3 0.35 0.34 0.51 0.33 0.58 0.38 0.34 0.26 0.31 0.51 0.57 0.37 0.37 0.35 0.45 gd2o3 3.90 0.92 4.91 1.51 3.17 3.03 1.76 4.73 3.74 1.85 0.78 1.22 0.89 1.49 1.46 gd2o3 3.84 0.92 4.30 1.02 4.50 0.95 1.11 0.71 0.93 4.34 1.97 1.18 1.34 3.74 1.71 tb2o3 0.05 0.00 0.12 0.12 0.11 0.12 0.07 0.10 0.02 0.11 0.05 0.08 0.05 0.08 0.09 tb2o3 0.03 0.01 0.06 0.06 0.05 0.06 0.07 0.00 0.06 0.09 0.15 0.09 0.07 0.02 0.06 dy2o3 0.24 0.22 0.40 0.39 0.51 0.48 0.34 0.38 0.16 0.31 0.17 0.23 0.22 0.29 0.21 dy2o3 0.22 0.11 0.18 0.26 0.31 0.15 0.30 0.12 0.23 0.20 0.38 0.32 0.18 0.20 0.31 ho2o3 0.06 0.00 0.00 0.00 0.04 0.05 0.00 0.00 0.01 0.06 0.08 0.03 0.05 0.04 0.00 ho2o3 0.01 0.00 0.05 0.01 0.00 0.00 0.00 0.00 0.03 0.00 0.00 0.00 0.02 0.02 0.05 er2o3 0.39 0.31 0.41 0.33 0.34 0.30 0.32 0.37 0.40 0.32 0.33 0.31 0.38 0.30 0.30 er2o3 0.43 0.34 0.39 0.33 0.38 0.34 0.35 0.31 0.36 0.39 0.29 0.30 0.32 0.40 0.34 tm2o3 0.34 0.09 0.40 0.10 0.13 0.03 0.11 0.40 0.25 0.12 0.08 0.08 0.08 0.08 0.11 tm2o3 0.36 0.04 0.32 0.12 0.36 0.06 0.14 0.05 0.08 0.39 0.07 0.09 0.06 0.34 0.06 yb2o3 0.13 0.08 0.12 0.17 0.14 0.16 0.14 0.14 0.12 0.13 0.15 0.13 0.13 0.18 0.11 yb2o3 0.11 0.10 0.14 0.15 0.13 0.08 0.16 0.08 0.11 0.17 0.13 0.10 0.12 0.12 0.15 lu2o3 0.07 0.05 0.15 0.07 0.10 0.05 0.04 0.13 0.20 0.08 0.05 0.09 0.14 0.12 0.09 lu2o3 0.12 0.02 0.03 0.06 0.10 0.09 0.08 0.10 0.12 0.08 0.05 0.10 0.12 0.16 0.12 feo 0.05 0.60 0.07 0.88 0.07 0.04 0.09 0.13 0.06 0.10 0.51 0.58 0.55 0.03 0.04 feo 0.00 0.50 0.02 0.10 0.62 0.41 0.18 0.48 0.61 0.10 0.16 0.50 0.00 0.69 0.26 so3 0.12 0.68 0.16 0.09 0.10 0.25 0.19 0.13 0.22 0.09 0.10 0.05 0.12 0.11 0.26 so3 0.04 0.09 0.11 0.13 0.48 0.10 0.10 0.35 0.13 0.10 0.36 0.07 0.28 0.18 0.62 cao 0.53 1.10 0.84 0.98 0.99 0.98 0.73 0.68 0.75 0.83 0.77 0.60 0.80 0.65 0.86 cao 0.45 0.57 0.58 0.63 0.84 0.64 0.68 0.76 0.82 0.60 0.88 0.68 0.91 0.77 1.09 sro 0.10 0.42 0.12 0.17 0.07 0.06 0.08 0.13 0.10 0.07 0.06 0.03 0.07 0.05 0.16 sro 0.04 0.05 0.07 0.05 0.19 0.06 0.06 0.09 0.08 0.08 0.20 0.05 0.16 0.08 0.44 al2o3 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 al2o3 0.00 0.01 0.01 0.00 0.02 0.00 0.00 0.00 0.00 0.00 0.04 0.00 0.00 0.00 0.02 total 101.18 100.97 103.28 100.71 99.55 99.67 100.09 103.08 104.05 99.95 99.30 99.34 100.50 100.25 98.72 total 103.61 99.49 103.83 99.50 104.66 100.83 100.43 100.27 99.85 103.77 98.16 98.82 99.13 104.09 100.82 si 0.05 0.08 0.04 0.06 0.11 0.06 0.04 0.05 0.05 0.10 0.11 0.12 0.08 0.05 0.06 si 0.06 0.07 0.08 0.06 0.04 0.07 0.06 0.03 0.08 0.05 0.06 0.14 0.04 0.04 0.07 p 3.88 3.68 3.81 3.79 3.78 3.80 3.81 3.79 3.80 3.77 3.76 3.74 3.77 3.84 3.83 p 3.81 3.80 3.80 3.80 3.76 3.85 3.79 3.80 3.77 3.81 3.80 3.72 3.81 3.80 3.71 as 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 as 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 pb 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 pb 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 th 0.08 0.17 0.11 0.16 0.22 0.14 0.10 0.10 0.10 0.21 0.18 0.17 0.18 0.10 0.10 th 0.10 0.14 0.10 0.12 0.05 0.13 0.15 0.08 0.18 0.11 0.10 0.22 0.13 0.10 0.11 u 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 u 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 y 0.04 0.06 0.05 0.05 0.07 0.07 0.05 0.05 0.05 0.06 0.06 0.05 0.06 0.14 0.03 y 0.05 0.05 0.03 0.06 0.03 0.06 0.05 0.04 0.06 0.03 0.04 0.05 0.03 0.05 0.03 la 0.77 0.70 0.73 0.77 0.28 0.30 0.59 0.74 0.83 0.49 0.67 0.81 0.70 0.56 0.84 la 0.87 0.77 0.86 0.69 0.78 0.67 0.68 0.90 0.70 0.78 0.73 0.64 0.90 0.77 0.78 ce 1.79 1.88 1.67 1.74 1.35 1.40 1.89 1.74 1.90 1.77 1.90 1.83 1.88 1.85 1.84 ce 1.82 1.93 1.74 1.92 1.78 1.87 1.90 1.99 1.88 1.80 1.75 1.85 1.86 1.85 1.83 pr 0.19 0.21 0.19 0.20 0.24 0.25 0.23 0.19 0.18 0.23 0.21 0.20 0.21 0.23 0.19 pr 0.19 0.21 0.19 0.22 0.19 0.21 0.22 0.20 0.21 0.19 0.20 0.22 0.19 0.19 0.21 nd 0.70 0.76 0.77 0.75 1.18 1.23 0.90 0.76 0.65 0.93 0.78 0.76 0.76 0.88 0.70 nd 0.71 0.74 0.72 0.82 0.73 0.79 0.82 0.65 0.77 0.72 0.80 0.81 0.67 0.70 0.76 sm 0.14 0.12 0.18 0.14 0.35 0.36 0.16 0.17 0.10 0.17 0.13 0.13 0.12 0.15 0.12 sm 0.13 0.12 0.14 0.13 0.15 0.13 0.13 0.09 0.12 0.15 0.16 0.13 0.11 0.12 0.14 eu 0.03 0.02 0.04 0.03 0.06 0.05 0.03 0.04 0.01 0.03 0.02 0.02 0.02 0.03 0.02 eu 0.02 0.02 0.03 0.02 0.03 0.02 0.02 0.01 0.02 0.03 0.03 0.02 0.02 0.02 0.02 gd 0.20 0.05 0.26 0.08 0.17 0.16 0.09 0.25 0.19 0.10 0.04 0.07 0.05 0.08 0.08 gd 0.20 0.05 0.22 0.05 0.23 0.05 0.06 0.04 0.05 0.23 0.11 0.06 0.07 0.19 0.09 tb 0.00 0.00 0.01 0.01 0.01 0.01 0.00 0.01 0.00 0.01 0.00 0.00 0.00 0.00 0.00 tb 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 dy 0.01 0.01 0.02 0.02 0.03 0.03 0.02 0.02 0.01 0.02 0.01 0.01 0.01 0.01 0.01 dy 0.01 0.01 0.01 0.01 0.02 0.01 0.02 0.01 0.01 0.01 0.02 0.02 0.01 0.01 0.02 ho 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ho 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 er 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 er 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.01 0.02 0.02 0.02 0.02 tm 0.02 0.00 0.02 0.01 0.01 0.00 0.01 0.02 0.01 0.01 0.00 0.00 0.00 0.00 0.01 tm 0.02 0.00 0.02 0.01 0.02 0.00 0.01 0.00 0.00 0.02 0.00 0.00 0.00 0.02 0.00 yb 0.01 0.00 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 yb 0.01 0.00 0.01 0.01 0.01 0.00 0.01 0.00 0.01 0.01 0.01 0.00 0.01 0.01 0.01 lu 0.00 0.00 0.01 0.00 0.01 0.00 0.00 0.01 0.01 0.00 0.00 0.00 0.01 0.01 0.00 lu 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.01 0.01 0.01 0.01 fe2+ 0.01 0.08 0.01 0.12 0.01 0.01 0.01 0.02 0.01 0.01 0.07 0.08 0.07 0.00 0.01 fe2+ 0.00 0.07 0.00 0.01 0.08 0.05 0.02 0.06 0.08 0.01 0.02 0.07 0.00 0.09 0.03 s 0.01 0.08 0.02 0.01 0.01 0.03 0.02 0.02 0.03 0.01 0.01 0.01 0.01 0.01 0.03 s 0.01 0.01 0.01 0.02 0.06 0.01 0.01 0.04 0.02 0.01 0.04 0.01 0.03 0.02 0.07 ca 0.09 0.19 0.14 0.17 0.17 0.17 0.13 0.11 0.13 0.14 0.13 0.10 0.14 0.11 0.15 ca 0.07 0.10 0.10 0.11 0.14 0.11 0.12 0.13 0.14 0.10 0.15 0.12 0.16 0.13 0.19 sr 0.01 0.04 0.01 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.00 0.01 0.00 0.01 sr 0.00 0.00 0.01 0.00 0.02 0.01 0.01 0.01 0.01 0.01 0.02 0.00 0.01 0.01 0.04 al 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 al 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 x(cheralite) 0.04 0.09 0.07 0.08 0.08 0.08 0.06 0.06 0.06 0.07 0.06 0.05 0.07 0.05 0.07 x(cheralite) 0.04 0.05 0.05 0.05 0.07 0.05 0.06 0.06 0.07 0.05 0.08 0.06 0.08 0.06 0.09 x(huttonite) 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.02 0.01 0.02 0.01 0.00 0.00 x(huttonite) 0.01 0.01 0.00 0.00 0.00 0.01 0.01 0.00 0.01 0.00 0.00 0.02 0.00 0.00 0.00 x(monazite) 0.96 0.91 0.94 0.92 0.90 0.92 0.95 0.95 0.95 0.91 0.92 0.93 0.92 0.95 0.94 x(monazite) 0.96 0.94 0.95 0.94 0.95 0.94 0.94 0.95 0.92 0.95 0.94 0.92 0.93 0.94 0.93 sum kat. 8.06 8.15 8.11 8.15 8.09 8.09 8.10 8.12 8.10 8.09 8.12 8.13 8.12 8.08 8.08 sum kat. 8.10 8.11 8.10 8.10 8.15 8.07 8.11 8.12 8.13 8.10 8.10 8.12 8.09 8.14 8.15 age (ma) 93.30 132.50 132.80 135.10 140.10 142.50 144.40 145.00 145.50 145.60 146.80 149.20 152.80 154.10 159.60 age (ma) 160.60 162.70 164.10 168.80 168.80 168.90 169.30 169.50 169.70 169.70 173.00 176.80 192.50 211.00 219.40 2 sd 8.10 11.50 11.50 11.70 12.10 12.30 12.50 12.60 12.60 12.60 12.70 12.90 13.20 13.30 13.80 2 sd 13.90 14.10 14.20 14.60 14.60 14.60 14.70 14.70 14.70 14.70 15.00 15.30 16.70 18.30 19.00 table 4. (continued) g eo lo gi a c ro at ic a geologia croatica 76/130 5.2. metamorphic evolution the mineralogical characteristics of the sample st-6 (chloritoid porphyroblasts with textural sector-hourglass zoning, hypidiomorphic chlorite blasts, synmetamorphic white micas) indicate metamorphic conditions of the greenschist to amphibolite facies. similar results can be seen in published studies (e.g. mposkos, 1989; bucher & grapes, 2011; castellanos-allarcòn et al., 2016). the c’-type shear band cleavage structure in sample st-6 points to specific ductile deformation mechanisms (fig. 3c) (passchier & trouw, 2005). the quartz grain boundaries formed by sgr and gbm processes (fig. 3f) are usually associated with recrystallization temperatures ranging from 400 to 600 ℃ (stipp et al., 2002). the two selected chloritoid blasts showed slight mg enrichment and mn depletion from the core towards the rim (fig. 7a; b), which is a typical feature of prograde metamorphism during the growth of chloritoid (e.g. mposkos, 1989; spear, 1995; franceschelli & memmi, 1999; koroknai et al., 2001). if we consider the p-t pseudosection with 10% of fe as fe2o3 to be the most appropriate for our sample (see lo pò & braga, 2014), the calculated fluid-free modal contents at these conditions are 78.7 vol% quartz, 13.1 vol% muscovite, 6.9 vol% chloritoid, 0.6 vol% chlorite, and 0.6 vol% ilmenite. thermodynamic modelling yielded an overlap of the isopleths of xfe in chlorite, xfe in chloritoid, and si in muscovite at peak metamorphic temperatures around 550 °c and pressures around 0.94 gpa (fig. 12). this result is also compatible with the results of the applied thermometers (chlorite–chloritoid: 527 – 568 °c, chlorite: 250 – 598 °c, tab. 5). the scatter of the chlorite thermometric results could be due to the high metamorphic temperature, which is not suitable figure 10. table with sem images of chloritoid schist from medvednica mt. the red ellipses indicate the position and names of emp measurements of chlorite (chl), chloritoid (ctd), muscovite (ms), rutile (rt), zircon (zrc) and quartz (q) (for results of measurements see tables 3 and 5). g eologia c roatica mišur et al.: petrochronological study of chloritoid schist from medvednica mountain (zagorje mid-transdanubian zone, croatia) 31 we note a considerable difference in the estimated p-t conditions for pmmc metasediments between our study and previous works (300 – 410 °c by the kübler index method; medium pressure by the b0 method, judik et al., 2004; 2008; 300 – 350 °c by chlorite thermometry, lugović et al., 2006). the b0 method applied to potassic white mica-bearing rocks of the pmmc (judik et al., 2004) is highly dependent on the mineral assemblage (massonne & schreyer, 1989; massonne & szpurka, 1997) and local equilibrium. for example, a graphical presentation of whole rock and the <2 µm fraction sample data (fig. 4 in judik et al., 2004) shows scattering from low-, mediumto high-pressure ranges with maximum frequency distributions in the medium-pressure range which is later ascribed to the values of 0.3 – 0.4 gpa. the likely reason for such a difference is that the investigated chloritoid schist is part of a sequence located at a higher metamorphic grade in comparison to the rocks studied by judik et al. (2004). the previous temperature estimates, based on the kübler index (illite crystallinity), empirical chlorite thermometry and vitrinite reflectance, should be taken as semiquantitative, but the difference of more than 100 °c between our study and the previous works (judik et al., 2004; 2008; lugović et al., 2006) cannot be a matter of the applied methods alone but also of the position in a metamorphic sequence. the temperature difference is considered to be broadly realistic and can be explained by a geodynamic scenario outlined in section 5.4. 5.3. monazite dating the investigated monazite grains are located in the cleavage domains (s1), which are mainly composed of syn-metamorphic white mica (fig. 8a). the u concentration in the investigated monazite is lower than 0.005 apfu (<0.0028 apfu) (tab. 4), which is characteristic of metamorphic monazite (spear & pyle, 2002). the measured monazite is highly irregular in shape and of small dimension (<200μm) (fig. 8b) which is also a typical feature of monazite in upper greenschistand amphibolite-facies rocks (parrish, for precise chlorite thermometry (see vidal et al., 2016), and/ or retrograde metamorphic reactions affecting chlorite. the geobarometry based on the si content in muscovite (after caddick & thompson, 2008) resulted in a pressure range from 0.87 to 0.99 gpa (at 550 ℃, tab. 5) which is also compatible with the modelling results. hence, we suggest that the metamorphic peak conditions were determined fairly precisely at 0.94 ± 0.05 gpa and 550 ± 20 °c (fig. 12). based on petrographic observations and thermodynamic calculations, the main mineral reaction to form chloritoid in sample st-6 is haematite + chlorite = magnetite + chloritoid + quartz + h2o. this reaction was also formulated by belak et al. (1995a). table 5. table with the results of the classic geobarometric calculations; geothermometer based on chloritoid – chlorite pairs (after vidal et al., 1999), chlorite geothermometer (after inoue et al., 2018) and phengite geobarometer (after caddick & thompson, 2008). chlorite-chloritoid geothermometry (vidal et al., 1999) chlorite-chloritoid pairs chlorite 1-15 1-19 1-25 2-12 2-49 2-9 2-14 2-43 2-1 2-16 chloritoid 1-10 1-1 1-32 2-11 2-50 2-10 2-15 2-44 2-2 2-17 t (°c) 545 568 556 546 553 561 556 534 527 547 average 549 °c min= 527 max= 568 chlorite thermometry (inoue et al., 1999) chlorite 1-18 1-23 1-27 1-30 1-46 1-48 1-53 2-6 2-38 2-3 2-19 t (°c) 598 363 385 400 331 452 411 424 365 370 362 chlorite 2-25 2-41 2-45 t (°c) 321 579 250 min= 250 max= 598 phengite barometry (chaddick & thompson, 2008) muscovite 1-11 1-12 1-16 1-17 1-20 1-28 1-29 1-50 1-52 min max t (°c) p (gpa) 600 0.94 1.07 1.01 0.99 1.01 1.06 0.98 1.06 1.00 0.94 1.07 550 0.87 0.99 0.94 0.92 0.94 0.98 0.90 0.98 0.93 0.87 0.99 500 0.79 0.92 0.86 0.84 0.86 0.91 0.83 0.91 0.85 0.79 0.92 450 0.72 0.84 0.79 0.77 0.79 0.83 0.75 0.83 0.78 0.72 0.84 average 0.94 gpa figure 11 .a discrimination diagram la/th versus hf for the investigated samples of metasediments from medvednica mt. in red circles, in the yellow circle is a sample (d7) from mišur et al. (2013) (after floyd & laveridge, 1987). g eo lo gi a c ro at ic a geologia croatica 76/132 1990; finger & krenn, 2007; schulz, 2021). no obvious relationship between age data and the shape of monazite grains is recorded. the presence of two age domains even within single monazite crystals (see tab 4, fig. 8b, e.g.; grain mnz 6, mnz 3, mnz e, mnz b, mnz 8) indicates a two-phase growth (or possible recrystallization and/or fluid overprinting) of monazite at 143 ± 2 ma and 167.5 ± 2 ma. the hree concentrations, followed by the y2o3 values indicate slightly different trends between younger and older monazite populations (tab. 4) with higher y2o3 concentrations in the younger monazite domains (fig. 9c). according to schulz, (2021), this feature could be related to a higher metamorphic grade in forming the younger population, but the influence of other assemblage phases, particularly the presence of xenotime could discourage that conclusion. nevertheless, the zonation of monazite indicates growth during different metamorphic phases (franz et al., 1996; heinrich et al., 1997; schulz, 2021). compared to previous ar-ar and k-ar dating of white mica and whole-rock (110 – 122 ma, belak et al., 1995a; 64 – 124 ma, judik et al., 2006; 122 – 135 ma borojević šoštarić et al., 2012) our study yielded older ages. even the oldest age from the literature is younger than the age of our young monazite group by about 8 ma. the monazite u-th total pb dating method has been proven to be a robust dating method for metamorphic conditions (parrish, 1991; montel et al., 1996; williams et al., 2007; schulz, 2021 and references therein), whereas the k-ar and ar-ar, methods suffer from resetting during higher metamorphic conditions because of the limited thermal retentivi ty of micas and feldspars resulting in the overprint of older metamorphic records (parrish, 1991). therefore, we assume that the previously published cretaceous k-ar and ar-ar ages represent cooling ages relevant to retrograde metamorphic conditions of the complex (e.g., ~300°c, according to van gelder et al., 2015) which is also suggested by judik et al. (2004). 5.4. geodynamic interpretation it is a common view that the opening and extension of the neotethys ocean between the tisia and adria microplates was followed by intra-oceanic subduction during which one part of the neotethys ocean was subducted (babić et al., 2002; pamić, 2002; karamata, 2006; schmid et al., 2008; 2020). subsequently, as a consequence of the shortening and subduction (i.e. closure of the ocean realm), a part of the oceanic crust collided and was obducted onto the cma to form ophiolites (lugović et al., 2006; schmid et al., 2008; 2020). it is possible that part of the cma, along with the oceanic neotethys crust, was subducted beneath the accretion melánge (middle jurassic-early cretaceous), and eventually, during subsequent divergence, exhumed to the surface along with thin parts of oceanic crust (see porkoláb et al., 2021). porkoláb et al. (2021) published numerical models of continental crust subducted beneath an oceanic plate utilizing thermo-mechanical simulations and the data from ophiolite belts around the world. in these models, the subducted continental crust, driven by buoyancy, extrudes along with fragments of the oceanic plate. a similar situation was described for the oman ophiolite region as a trench-passive margin (see robertson, 2004; and references therein). part of the configure 12. pseudosection diagram calculated in the system mnnckfmashto for sample st-6, (perple_x software package, connolly & petrini, 2002; connolly, 1990; 2005). the numbers in the circles refer to mineral assemblages given at the bottom. abbreviations: and – andalusite; bio – biotite; ca – carpholite; chl – chlorite; ctd – chloritoid; gt – garnet; ilm – ilmenite; mica – muscovite; st – stilpnomelane; ru – rutile; q – quartz. left hand side: calculated stability polygons with indicated mineral phases with legend below. right hand side: graph with isopleths of chloritoid (red line), chlorite (yellow line) and muscovite (blue line). the dark grey polygon marks the intersection of the chlorite, chloritoid and muscovite isopleths. the diagram on the right hand side at the bottom presents the results of the classic thermobarometric calculations. g eologia c roatica mišur et al.: petrochronological study of chloritoid schist from medvednica mountain (zagorje mid-transdanubian zone, croatia) 33 tinental crust (arabian plate) along with the oceanic neotethys crust was subducted under an accretion melánge until its thickened wedge prevented further subduction and was followed by buoyancy-driven exhumation (robertson, 2004). the omantype trench-passive margin collision model is widely applicable to the eastern mediterranean region and explains the emplacement of most of the jurassic and cretaceous ophiolites onto former passive margins (robertson, 2004). if we apply the above model to the part of the cma that was subducted to depths of 35 – 38 km (0.94 gpa) and heated up to 550 °c according to the investigated chloritoid schist, this part would have been originally located close to the sole of the hot ophiolite that was later obducted. metasediments of the pmmc that had experienced lower temperatures (300 – 410 °c) could have been not so deeply subducted with the consequence that their peak pressures were also lower. the age of the older monazite group (ca. 167.5 ma) of the studied chloritoid schist, should then be related to the metamorphic event caused by the subduction of an external part of the cma below the oceanic lithosphere. this age is consistent with those interpreted so far, referring to regional processes related to the adria-europe subduction margin during the middle jurassic (e.g. lanphere et al., 1975, ages from 160 – 170 ma, okrusch et al., 1978, ages from 161 – 169 ma; dimo-lahitte et al., 2001, ages from 160 – 174 ma; schmid et al., 2008; 2020; šegvić et al., 2014; 2019; 2020 ages from 160 – 162 ma; belak et al., 2022 ages from 150 – 165 ma). the younger monazite group (143 ma) could be related to the obduction process which included parts of the subducted cma along with parts of the oceanic crust (lugović et al., 2006). in the model of porkoláb et al. (2021), subduction and exhumation cycles usually last about 10 to 30 ma, which would agree with the difference in age of our monazite groups. 6. conclusions the investigated chloritoid schist from medvednica mt. originated by metamorphism of clastic sediment accumulated at the edge of the cma. peak metamorphic conditions of 0.94 ± 0.05 gpa and 550 ± 20 °c were estimated by applying pseudosection modelling and classical geothermobarometry. the formation of metamorphic monazite in the studied chloritoid schist occurred at 167 ± 2 ma and 143 ma ± 2 ma. the ages are interpreted to correspond to two distinct metamorphic episodes. the metamorphic changes in the investigated rocks are initiated by regional subduction-accretion tectonics, synchronous with regional processes of the west vardar ophiolite obduction onto the cma during the late jurassic. acknowledgment we would like to thank the personnel from the laboratory for sample preparation of the croatian geological survey for the support that enabled this research. support by the croatian science foundation (ip-2014-09-9541)and by the croatian ministry of science, education, and sports within the frame of the grant no. 181-1811096-1093 is acknowledged. we would also like to thank andrea mišur, marko špelić and marija horvat for their valuable suggestions in preparing the manuscript. references abd elmola, a., charpentier, d., buatier, m., lanari, p. & monié, p. (2017): textural-chemical changes and deformation conditions registered by phyllosilicates in a fault zone (pic de port vieux thrust, pyrenees).– applied clay science, 144, 88–103. doi: 10.1016/j.clay.2017.05.008. andersson, s.s., wagner, t., jonsson, e. & michallik, r.m. (2018): mineralogy, paragenesis, and mineral chemistry of rees in the olserum-djupedal ree-phosphate mineralization, se sweden.– american mineralogist, 103, 125–142. doi: 10.2138/am-2018-6202 arbiol, c., layne, g.d., zanoni, g. & šegvić, b. (2021): characteristics and genesis of phyllosilicate hydrothermal assemblages from neoproterozoic epithermal au-ag mineralisation of the avalon zone of newfoundland, canada.– applied clay science, 202, 105960. doi: 10.1016/j.clay.2020.105960 babić, lj., hochuli, p.a. & zupanič, j. (2002): the jurassic ophiolitic mélange in the ne dinarides: dating, internal structure and geotectonic implications.– eclogae geologicae helvetiae, 95, 263–275. doi: 10.5169/seals-168959 bailey, s.w. (1980): summary of recommendations of aipea nomenclature committee on clay minerals.– american mineralogist, 65, 1–7. balen, d., horváth, p., finger, f. & starijaš, b. (2013): phase equilibrium, geothermobarometric and xenotime age dating constrains on the alpine metamorphism recorded in chloritoid schists from the southern part of the tisia mega-unit (slavonian mts., ne croatia).– international journal of earth sciences., 102/4, 1091–1109. doi: 10.1007/500531-012-0850-8 basch, o. (1983a): osnovna geološka karta sfrj 1:100.000, list ivanić-grad l33-81 [basic geological map of sfry 1:100000, ivanić-grad sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd. basch, o. (1983b): osnovna geološka karta sfrj 1:100.000, tumač za list ivanićgrad [basic geological map of sfry 1:100000, geology of the ivanić-grad sheet – in croatian].– geološki zavod, zagreb, savezni geološki zavod, beograd, 81 p. belak, m. (2005): metamorfne stijene plavih i zelenih škriljavaca na medvednici [metamorphic rocks of the blueschist and greenschist on the medvednica mt. – in croatian, with an english abstract].– unpubl. phd thesis, faculty of science, university of zagreb, 295 p. belak, m. & tibljaš, d. (1998): discovery of the blueschist in the medvednica mountain (northern croatia) and their significance for the interpretation of the geotectonic evolution of the area.– geologia croatica, 51/1, 27–32. doi: 10.4154/ gc.199/05 belak, m., pamić, j., kolar-jurkovšek, t., peckay, z. & karan, d. (1995a): alpinski regionalnometamorfni kompleks medvednice (sjeverozapadna hrvatska) [alpine low-grade regional metamorphic complex of mt. medvednica northwestern croatia – in croatian].– in: vlahović, i. et al. (eds): 1st croatian geological congress, proceedings, 1, 67–70. belak, m., sremac, j., crnko, j. & kolar-jurkovšek, t. (1995b): paleozojske stijene niskog stupnja metamorfizma na jugoistočnoj strani medvednice (sjeverozapadna hrvatska) [palaeozoic rocks of low metamorphic degree on the southeastern side of medvednica (northwestern croatia) – in croatian].– in: vlahović, i. et al. (eds): 1st croatian geological congress, proceedings, 1, 71–74. belak, m., slovenec, d., kolar-jurkovšek, t., garašić, v., pécskay, z., tibljaš, d & mišur, i. (2022): low-grade metamorphic rocks of the tethys subduction–collision zone in the medvednica mt. (nw croatia).– geologica carpathica, 73, 3, 207–229. doi: 10.31577/geolcarp.73.3.3 bhatia, m.r. & crook, k.a.w. (1986): trace element characteristics of greywackes and tectonic setting discrimination of sedimentary basins.– contributions to mineralogy and petrology, 92, 181–193. boynton, w.v. (1984): geochemistry of the rare earth elements: meteorite studies.– in: henderson, p. (ed.): rare earth element geochemistry, elsevier, amsterdam, 63–114. borojević šoštarić, s., neubauer, f., robert, h. & palinkaš, a.l. (2012): tectonothermal history of the basement rocks within the nw dinarides: new 40ar/39ar ages and synthesis.– geologica carpathica, 63, 441–452. doi: 10.2478/v10096-012-0034-2 bucher, k. & grapes, r. (2011): petrogenesis of metamorphic rocks.– springerverlag berlin heidelberg, 419. doi: 10.1007/978-3-540-74169-5 caddick, m.j. & thompson, a.b. (2008): quantifying the tectono-metamorphic evolution of pelitic rocks from a wide range of tectonic settings: mineral composition in equilibrium.– contributions to mineralogy and petrology, 156, 177–195. doi: 10.1007/s00410-008-0280-6 camilleri, p.a. (2018): classification, character, and origin of textural zoning in porphyroblasts: significance and relation to strain.– journal of the tennessee academy of science, 93, 1-2, 50–60. castellanos-alarcón, o.m., ríos-reyes, c.a. & garcía-ramírez, c.a., (2016): occurrence of chloritoid-bearing metapelitic rocks and their significance in the metamorphism of the silgará formation at the central santander massif.– boletín de ciencias de la tierra, 40, 5-15. doi: 10.15446/rbct.n40.48416 chauvenet, w. (1863): a manual of spherical and practical astronomy, vol. 2.– j. b. lippincott company, philadelphia, pa. connolly, j.a.d. (1990): multivariable phase-diagrams— an algorithm based on generalised thermodynamics.– american journal of science, 290, 666–718. connolly, j.a.d. (2005): computation of phase equilibria by linear programming: a tool for geodynamic modeling and its application to subduction zone decarbong eo lo gi a c ro at ic a geologia croatica 76/134 ation.– earth and planetary science letters, 236, 524–541. doi: 10.1016/j. epsl.2005.04.033 connolly, j.a.d. & petrini, k. (2002): an automated strategy for calculation of phase diagram sections and retrieval of rock properties as a function of physical conditions.– journal of metamorphic geology, 20/7, 697–708. doi: 10.1046/j.1525-1314.2002.00398.x csontos, l. & nagymarosy, a. (1998): the mid-hungarian line: a zone of repeated tectonic inversions.– tectonophysics, 297/1, 51–71. doi: 10.1016/s00401951(98)00163-2 cullers, r.l. (1994a): the chemical signature of source rocks in size fractions of holocene stream sediment derived from metamorphic rocks in the wet mountains region, colorado, usa.– chemical geology, 113, 327–343. doi: 10.1016/00092541(94)90074-4 cullers, r.l. (1994b): the controls on the major and trace element variation of shales, siltstones, and sandstones of pennsylvanian-permian age from uplifted continental blocks in colorado to platform sediment in kansas, usa.– geochimica et cosmochimica acta, 58, 4955–4972. doi: 10.1016/0016-7037(94)90224-0 cullers, r.l. (2000): the geochemistry of shales, siltstones and sand stones of pennsylvanian-permian age, colorado, usa: implications for provenance and metamorphic studies.– lithos, 51, 181–203. doi: 10.1016/50024-4937(99)0063-8 cullers, r.l. (2002): implications of elemental concentrations for provenance, redox conditions, and metamorphic studies of shales and limestones near pueblo, co, usa.– chemical geology, 191, 305–327. doi: 10.1016/s0009-2541(02)00133-x dimo-lahitte, a., monie, p. & vergely, p. (2001): metamorphic soles from the albanian ophiolites: petrology, 40ar/39ar geochronology, and geodynamic evolution.– tectonics, 20, 78–96. doi: 10.1029/2000tc900024 đurđanović, ž. (1973): o paleozoiku i trijasu medvednice (zagrebačke gore) i područja dvora na uni na temelju konodonata [on the palaeozoic and triassic of medvednica (zagrebačke gora) and the dvor na una area based on conodonts (in croatian)].– geološki vjesnik, 25, 29–49. finger, f. & krenn, e. (2007): three metamorphic monazite generations in a highpressure rock from the bohemian massif and the potentially important role of apatite in stimulating polyphase monazite growth along a pt loop.– lithos, 95, 103–115. doi: 10.1016/j.lithos.2006.06.003 floyd, p.a. & leveridge, b.e. (1987): tectonic environment of the devonian gramscatho basin, south cornwall: framework mode and geochemical evidence from turbiditic sandstones.– journal of the geological society of london, 144, 531–542. doi: 10.1144/gsjgs.144.4.0531 fodor, l., jelen, b., márton, e., skaberne, d., čar. j. & vrabec, m. (1998): miocene‐pliocene tectonic evolution of the slovenian periadriatic fault: implications for alpine‐carpathian extrusion models.– tectonics, 17/5, 690–709. doi: 10.1029/98tc01605 foster, m.d. (1962): interpretation of the composition and a classification of the chlorites.– u.s. geological survey professional paper, 414, 1–33. franz, g., andrehs, g., & rhede, d. (1996): crystal chemistry of monazite and xenotime from saxothuringian-moldanubian metapelites, ne bavaria, germany.– eur. j. mineral. 8, 1097–1118. doi: 10.1127/ejm/8/5/1097 franceschelli, m. & memmi, i. (1999): zoning of chloritoid from kyanite-facies metapsammites, alpi apuane, italy.– mineralogical magazine, 63/1, 105–110. doi: 10.1180/minmag.1999.063.1.10 fuhrman, m.l. & lindsley, d.h. (1988): ternary-feldspar modelling and thermometry.– am. mineral., 73, 201–215. haas, j., mioč, p., pamić, j., tomljenović, b., árkai, p., bérczi-makk, a. & rálisch-felgenhauer, e. (2000): complex structural pattern of the alpine–dinaridic–pannonian triple junction.– international journal of earth sciences, 89/2, 377–389. doi: 10.1007/s005310000093 heinrich, w., andrehs, g., & franz, g. (1997): monazite-xenotime miscibility gap thermometry. i. an empirical calibration.– j. metamorph. geol., 15, 3–16. doi: 10.1111/j.1525-1314.1997.t01-1-00052.x inoue, a., inoue, s. & utada, m. (2018): application of chlorite thermometry to estimation of formation temperature and redox conditions.– clay minerals, 53, 143–158. doi: 10.1180/clm.2018.10 janoušek, v., farrow, c.m. & erban, v. (2006): interpretation of whole-rock geochemical data in igneous geochemistry: introducing geochemical data toolkit (gcdkit).– journal of petrology, 47/6, 1255–1259. doi: 10.1093/petrology/egl013 judik, k., árkai, p., horváth, p., et al. (2004): diagenesis and low-temperature metamorphism of mt. medvednica, croatia: mineral assemblages and phyllosilicate characteristics.– acta geologica hungarica, 47, 151–176. doi: 10.1556/ ageol.47.2004.2-3.5 judik, k., balogh, k., tibljaš, d. & árkai, p. (2006): new age data on the lowtemperature regional metamorphism of mt. medvednica (croatia).– acta geologica hungarica, 49, 207–221. doi: 10.1556/ageol.49.2006.3.2 judik, k., rantitsch, g., rainer, t.m., et al. (2008): alpine metamorphism of organic matter in metasedimentary rocks from mt. medvednica (croatia).– swiss journal of geosciences, 101, 605–616. doi: 10.1007/s00015-008-1303-z karamata, s. (2006): the geological development of the balkan peninsula related to the approach, collision and compression of gondwana and eurasian units.– in: robertson, ahf & mountrakis, d. (eds.): tectonic development of the eastern mediterranean region.– geological society, london, special publications, 260, 155–178. koroknai, b., horváth, p. & németh, t. (2001): chloritoid schist from the uppony mts (ne hungary): mineralogical, petrological and structural data from a new occurrence.– acta geologica hungarica, 44/1, 47–65. lanphere, m.a., coleman, r.g., karamata, s. & pamić, j. (1975): age of amphibolites associated with alpine peridotites in the dinaride ophiolite zone, yugoslavia.– earth and planetary science letters, 26, 271–276. doi:10.1016/0012 821x(75)90001-1 li, b., massonne, h.-j., koller, f. & zhang, j.-f. (2021): metapelite from the high-ultrahigh pressure terrane of the eastern alps (pohorje mts., slovenia) – new pressure, temperature, and time constraints on a polymetamorphic rock.– journal of metamorphic geology, 39/6, 695-726. doi: 10.1111/jmg.12581 lo pò, d. & braga, r. (2014): influence of ferric iron on phase equilibria in greenschist facies assemblages: the hematite-rich metasedimentary rocks from the monti pisani (northern apennines).– journal of metamorphic geology, 32, 371–387. doi: 10.1111/jmg.12076 lugović, b., šegvić, b. & altherr, r. (2006): petrology, geochemistry and tectonic significance of the orthogreenschists from the sw zagorje-mid-transdanubian zone (medvednica mts, croatia).– ofioliti, 31/1, 39–50. massonne, h.-j. (2012): formation of amphibole and clinozoisite-epidote in eclogite owing to fluid infiltration during exhumation in a subduction channel.– journal of petrology, 53, 1969–1998. doi: 10.1093/petrology/egs040 massonne, h.-j. (2014): wealth of p–t–t information in medium-high grade metapelites: example from the jubrique unit of the betic cordillera, s. spain.– lithos, 208-209, 137–157. doi: 10.1016/j.lithos.2014.08.027 massonne, h.-j. & schreyer, w. (1989): stability field of the highpressure assemblage talc + phengite and two new phengite barometers.– european journal of mineralogy, 1, 391–410. doi: 10.1127/ejm/1/3/0391 massonne, h.-j. & szpurka, z. (1997): thermodynamic properties of white micas on the basis of high-pressure experiments in the systems k2o-mgo-al2o3-sio2h2o and k2o-feo-al2o3-sio2-h2o.– lithos, 41, 229–250. doi: 10.1016/ s0024-4937(97)82014-2 massonne, h.-j., dristas, j.a. & martínez, j.c. (2012): metamorphic evolution of the río de la plata craton in the cinco cerros area, buenos aires province, argentina.– journal of south american earth sciences, 38, 57–70. doi: 10.1016/j. jsames.2012.05.005 mclennan, s.m., (2001): relationships between the trace element composition of sedimentary rocks and upper continental crust.– geochemistry geophysics geosystems, 2, 1021. doi:10.1029/2000gc000109 mclennan, s.m. & taylor, s.r. (1991): sedimentary rocks and crustal evolution: tectonic setting and secular trends.– j. geol., 99, 1–21. doi: 10.1086/629470 mišur, i. (2017): geodinamska evolucija metasedimentnih stijena niskog stupnja metamorfizma na medvednici [geodynamic evolution of low grade metasedimentary rocks on the mt. medvednica.– in croatian, with an english abstract].– unpubl. phd thesis, faculty of science, university of zagreb, 215 p. mišur, i., belak, m. & balen, d. (2013): petrographic features of chloritoid schist from southeastern slopes of mt. medvednica, (zagorje-mid-transdanubian zone, croatia).–in: schuster, r. (ed.): 11th workshop on alpine geological studies and 7th european symposium on fossil algae, abstracts & field guides. wien, geologische bundesanstalt, 66–67. mišur, i., belak, m., klötzli, u. & balen, d. (2015): evidence from chloritoid schists for muli-stage metamorphism in the mt. medvednica area (zagorje mid transdanubian zone, n croatia).– in: koller, f., kolitsch, u. & tessadri, r. (eds.): minpet2015, mitteilungen österreichischen minerogischen gesellschaft, 161, 89-89. montel, j., foret, s., veschambre, m., nicollet, c. & provost, a. (1996): electron microprobe dating of monazite.– chemical geology, 131, 37–53. doi: 10.1016/0009-2541(96)00024-1 mposkos, e. (1989): high-pressure metamorphism in gneisses and pelitic schists in the east rhodope zone (n. greece).– mineralogy and petrology, 41, 25–39. doi:10.1007/bf01164808 okrusch, m., seidel, e., kreuzer, h. & harre, w. (1978): jurassic age of metamorphism at the base of the brezovica peridotite (yugoslavia).– earth and planetary science letters, 39, 291–297. doi: 10.1016/0012-821x(78)90205-4 ondrejka, m., uher, p., putiš, m., broska, i., bačík, p., konečný, p. & schmiedt, i. (2012): two stage breakdown of monazite by post-magmatic and metamorphic fluids: an example from the veporic orthogneiss, western carpathians, slovakia.– lithos 142–143, 245–255. doi: 10.1016/j.lithos.2012.03.012 pamić, j. (1984): triassic magmatism of the dinarides in yugoslavia.– tectonophysics, 109/3–4, 273–307. pamić, j. (2002): the sava-vardar zone of the dinarides and hellenides versus the vardar ocean.– eclogae geologicae helvetiae, 95, 99–113. g eologia c roatica mišur et al.: petrochronological study of chloritoid schist from medvednica mountain (zagorje mid-transdanubian zone, croatia) 35 pamić, j. & tomljenović, b. (1998): basic geological data from the croatian part of the zagorje-mid-transdanubian zone.– acta geologica hungarica, 41(4), 389–400. parrish, r.r. (1990): u-pb dating of monazite and its application to geological problems.– canadian journal of earth sciences, 27, 1431–1450. doi: 10.1139/e90-152 parry, w.t., ballantyne, j.m. & jacobs, d.c. (1984): geochemistry of hydrothermal sericite from roosevelt hot springs and the tintic and santa rita porphyry copper systems.– econ. geol. 79, 72–86. doi: 10.2113/gsecongeo.79.1.72. passchier, c.w. & trouw, r.a.j. (2005): microtectonics.– heidelberg, springerverlag berlin, 366 p. doi: 10.1007/978-3-662-08734-3 porkoláb, k., duretz, t., yamato, p., auzemery, a. & willingshofer, e. (2021): extrusion of subducted crust explains the emplacement of far-travelled ophiolites.– nature communications, 12, 1499. doi: 10.1038/s41467-021-21866-1 pouchou, j.l. & pichoir, f. (1984): a new model for quantitative analysis: part i. application to the analysis of homogeneous samples.– larecherche aerospatiale, 3, 13–38. pouchou, j.l. & pichoir, f. (1991): quantitative analysis of homogeneous or stratified microvolumes applying the model “pap”.– in: heinrich, k.f.j. & newbury, d.e. (ed), electron probe quantitation, plenum, new york, 31–75. doi: 10.1007/978-1-4899-2617-3_4 pyle, j.m., spear, f.s., rudnick, r.l. & mcdonough, w.f. (2001): monazite–xenotime–garnet equilibria in metapelites and a new monazite–garnet thermometer.– journal of petrology, 42, 2083–2107. doi: 10.1093/petrology/42.11.2083 robertson, a (2004): development of concepts concerning the genesis and emplacement of tethyan ophiolites in the eastern mediterranean and oman regions.– earth-science reviews, 66, 331–387. doi: 10.1016/j.earscirev.2004.01.005 schefer, s., egli, d., missoni, s., bernoulli, d., fügenschuh, b., gawlick, h.-j., jovanović, d., krystyn, l., lein, r., schmid, s.m. & sudar, m.n. (2010): triassic metasediments in the internal dinarides (kopaonik area, southern serbia): stratigraphy, palaeogeographic and tectonic significance.– geologica carpathica 61, 89–109. doi: 10.2478/v10096-010-0003-6 schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpinecarpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss journal of geosciences, 101, 139–183. doi: 10.1007/s00015-0081247-3 schmid, s.m., bernoulli, d., fügenschuh, b., georgiev, n., kounov, a., matenco, l., oberhänsli, r., pleuger, j., schefer, s., ustaszewski, k. & van hinsbergen, d. (2016): map of the tectonic units of the alpine collision zone between eastern alps and western turkey. https://www.researchgate.net/publication/292606123 schmid, s.m., fügenschuh, b., kounov, a., matenco, l., nievergelt, p., oberhänsli, r., pleuger, j., schefer, s., schuster, r., tomljenović, b., ustaszewski, k. & van hinsbergen, d.j.j. (2020): tectonic units of the alpine collision zone between eastern alps and western turkey.– gondwana research, 78, 308–374. doi: 10.1016/j.gr.2019.07.005 schulz, b. (2021): monazite microstructures and their interpretation in petrochronology.– frontiers in earth science, 9, 668566. doi: 10.3389/feart.2021.668566 slovenec, d., lugović, b. & vlahović, i. (2010): geochemistry, petrology and tectonomagmatic significance of basaltic rocks from the ophiolite mélange at the nw external-internal dinarides junction (croatia).– geologica carpathica, 61, 4, 273–292. doi: 10.2478/v10096-010-0016-1 slovenec, d., šegvić, b., halamić, j., goričan, š. & zanoni, g. (2020): an ensialic volcanic arc along the northwestern edge of palaeotethys—insights from the mid‐triassic volcanosedimentary succession of ivanščica mt. (northwestern croatia).– geological journal, 55, 4324–4351. doi: 10.1002/gj.3664 spear, f.s. (1995): metamorphic phase equilibria and pressure-temperature-time paths. monograph 1 (2nd reprinted edition).mineralogical society of america, chantilly, virginia, 799. spear, f. s. & pyle, j. m. (2002): apatite, monazite and xenotime in metamorphic rocks.– rev. mineral. geochem. 48, 293–335. doi: 10.1515/9781501509636-010 stipp, m., stünitz, h., heilbronner, r. & schmid, s. m. (2002): dynamic recrystallisation of quartz: correlation between natural and experimental conditions.– in: s. de meer et al. (eds.): deformation mechanisms, rheology and tectonics: current status and future perspectives. geol. soc. spec. publ., 200, 171 – 190. suzuki, k & kato, t (2008): chime dating of monazite, xenotime, zircon and polycrase: protocol, pitfalls and chemical criterion of possibly discordant age data.– gondwana research, 14, 569–586. doi: 10.1016/j.gr.2008.01.005 šegvić, b., kukoč, d., dragičević, i., vranjković, a., brčić, v., goričan, š., babajić, e. & hrvatović, h. (2014): new record of middle jurassic radiolarians and evidence of neotethyan dynamics documented in a mélange from the central dinaridic ophiolite belt (cdob, ne bosnia and herzegovina).– ofioliti, 39, 33–43. doi:10.4454/ofioliti.v39i1.427 šegvić, b., slovenec, d., altherr, r., babajić, e., mählmann, r.f. & lugović, b. (2019): petrogenesis of high-grade metamorphic soles from the central dinaric ophiolite belt and their significance for the neotethyan evolution in the dinarides.– ofioliti, 44, 1–30. doi:10.4454/ofioliti.v44i1.462 šegvić, b., slovenec, d., schuster, r., babajić, e., badurina, l. & lugović, b. (2020): sm-nd geochronology and petrologic investigation of a sub-ophiolite metamorphic sole from the dinarides (krivaja-konjuh ophiolite complex, bosnia and herzegovina).– geologia croatica, 73/2, 119–130. doi: 10.4154/gc.2020.09 šikić, k., basch, o. & šimunić, a. (1978): osnovna geološka karta sfrj, list zagreb 1:100.000 l 33-80 [basic geological map of sfry 1:100000, zagreb sheet – in croatian].– institut za geološka istraživanja, zagreb, savezni geološki zavod beograd. šikić, k., basch, o. & šimunić, a. (1979): tumač osnovne geološke karte sfrj 1:100.000 l 33-80, list zagreb [basic geological map of sfry 1:100000, geology of the zagreb sheet – in croatian].– institut za geološka istraživanja, zagreb, savezni geološki zavod beograd. taylor, s.r. & mclennan, s.m. (1995): the geochemical evolution of the continental crust.– reviews of geophysics, 33/2, 241–265. doi: 10.1029/95rg00262 tischendorf, g., förster, h.j., gottesmann, b., rieder, m., (2007): true and brittle micas: composition and solid-solution series.– mineralogical magazine, 71/3, 285–320. doi: 10.1180/minmag.2007.071.3.285. toljić, m., matenco, l., ducea, m.n., stojadinović, u., milivojević, j. & đerić, n. (2013): the evolution of a key segment in the europe-adria collision: the fruška gora of northern serbia.– global planet. change, 103, 39–62. doi: 10.1016/j.gloplacha.2012.10.009 tomljenović, b. (2002): strukturne značajke medvednice i samoborskog gorja [structural characteristics of medvednica and samoborsko gorje mountains – in croatian, with an english abstract].– unpubl. phd thesis, faculty of science, university of zagreb, faculty of mining, geology and petroleum engineering. 208 p. tomljenović, b., csontos, l., márton, e. & márton, p. (2008): tectonic evolution of the northwestern internal dinarides as constrained by structures and rotation of medvednica mountains, north croatia.– geological society london, special publications, 298, 145–167. doi: 10.1144/sp298.8 ustaszewski, k., schmid, s.m., fügenschuh, b., tischler, m., kissling, e. & spakman, w. (2008): a map-view restoration of the alpine carpathian-dinaridic system for the early miocene.– swiss journal of geosciences, 101/1, 273–294. doi: 10.1007/s00015-008-1288-7 ustaszewski, k., schmid, s.m., lugović, b., schuster, r., schaltegger, u., bernoulli, d., hottinger, l., kounov, a., fügenschuh, b. & schefer, s. (2009): late cretaceous intra-oceanic magmatism in the internal dinarides (northern bosnia and herzegovina): implications for the collision of the adriatic and european plates.– lithos, 108/1–4, 106–125. doi: 10.1016/j. lithos.2008.09.010 van gelder, i.e., matenco, l., willingshofer, e., tomljenović, b., andriessen, p.a.m., ducea, m.n. & gruić, a. (2015): the tectonic evolution of a critical segment of the dinarides‐alps connection: kinematic and geochronological inferences from the medvednica mountains, ne croatia.– tectonics 34/9, 1952–1978. doi: 10.1002/2015tc003937 vermeesch, p. (2018): isoplotr: a free and open toolbox for geochronology.– geoscience frontiers, v.9, 1479–1493. doi: 10.1016/j.gsf.2018.04.001. vernon, r. h. (2004): a practical guide to rock microstructure.– cambridge university press, cambridge, 594. doi: 10.1017/cbo9780511807206 vidal, o., goffé, b., bousquet, r. & parra, t. (1999): calibration and testing of an empirical chloritoid-chlorite mg-fe exchange thermometer and thermodynamic data for daphnite.– journal of metamorphic geology, 17, 25–39. doi: 10.1046/j.1525-1314.1999.00174.x vidal, o., lanari, p., munoz, m., bourdelle, f. & de andrade, v. (2016): deciphering temperature, pressure, and oxygen activity conditions of chlorite formation.– clay minerals, 51, 615–633. doi: 10.1180/claymin.2016.051.4.06 vragović, m. & majer, v. (1979a): kloritoidni škriljci u metamorfnim kompleksima u sjevernoj hrvatskoj (jugoslavija) [chloritoid schists in metamorphic complexes in northern croatia (yugoslavia)(in croatian)].– geološki vijesnik, 31, 287–294 vragović, m. & majer,v. (1979b): prilozi za poznavanje metamorfnih stijena zagrebačke gore, moslavačke gore i papuka (hrvatska, jugoslavija)[contributions to the knowledge of metamorphic rocks of zagrebačka mt., moslavačka mt. and papuk mt. (croatia, yugoslavia)(in croatian)].– geol. vjesnik, 31, 295–308. williams, m., jercinovic, m.j. & hetherington, c.j. (2007): microprobe monazite geochronology: understanding geologic processes by integrating composition and chronology.– annual review of earth and planetary sciences, 35, 137–175. doi: 10.1146/annurev.earth.35.031306.140228. white, r.w., powell, r., holland, j.b., johnson, t.e. & green, e.c.r. (2014): new mineral activity–composition relations for thermodynamic calculations in metapelitic systems.– journal of metamorphic geology, 32, 261–286. doi: 10.1111/jmg.12071 zane, a. & weiss, z. (1998): a procedure for classifying rock-forming chlorites based on microprobe data.– rendiconti lincei, 9, 51–56. doi: 10.1007/bf02904455 g eo lo gi a c ro at ic a geologia croatica 76/136 supplementary data supplement 1. pseudosection calculated in the system mnnckfmashto with various (0%, 5%, 15%, 20%) percentages of ferric iron in the bulk-rock composition of sample st-6, (mnnckfmashto = mno–na2o–cao–k2o–feo–mgo–al2o3–sio2–h2o–tio2–o2) using the perple_x software package (connolly & petrini, 2002; connolly, 1990; 2005). the numbers in the circles refer to mineral assemblages given at the bottom. abbreviations: and – andalusite; bio – biotite; ca – carpholite; chl – chlorite; ctd – chloritoid; gt – garnet; ilm – ilmenite; mica – muscovite; st –staurolite; ru – rutile; q – quartz. the coloured lines in the diagrams refer to isopleths of chloritoid (red), muscovite (blue), and chlorite (yellow). www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2025 | 78/1 | 31–44 | 8 figs. | 1 suppl. | 1. introduction human interest in karst groundwater has been impacted by the huge amount of good quality water that karst aquifers can accumulate and yield. about 21.6% of the european land surface is covered by carbonate rocks, with a total area of actual carbonate rock outcrops of 13.8% of the total european surface. similar coverage of the surface, with limestone of the mesozoic period, occurs in serbia with open karst over 10.3% of the area (chen et al., 2017). therefore, it is necessary and crucial, to become familiar with karst aquifer characteristics to manage it sustainably. in karst areas, the upper layer of epikarst could play a crucial role in protecting karstic formations. epikarst re pre­ sents the highest part of the rock mass exposed to karstification, i.e. a layer of partially altered bedrock that has not yet deve­ loped into soil. in this layer, water permeability (due to cracking) and the diffuse circulation of water are significantly higher and more evenly distributed both vertically and horizontally compared to the rest of the karstified rock mass (klimchouk, 2000). in most karst regions and formations, the presence of an epikarst zone is expected. the thickness of the epikarst zone can vary widely, from 10 cm to 30 m, epikarst of the eastern part of suva planina mt.: a new perspective defined from an integrated survey branislav petrović1*, snežana ignjatović1, živojin smiljković2, veljko marinović1, violeta gajić1 1 university of belgrade, faculty of mining and geology, đušina 7, 11000 belgrade, serbia; (*corresponding author: branislav.petrovic@rgf.bg.ac.rs) 2 serbian environmental protection agency, žabljačka 10a, 11000 belgrade, serbia doi: 10.4154/gc.2025.03 abstract human interest in karst groundwater stems from the high-quality water that karst aquifers can accumulate. in europe, 21.6% of the land is covered by carbonate rocks, with serbia having 10.3% karst coverage. understanding karst aquifers is essential for sustainable water management. the epikarst layer has higher water permeability and diffuse circulation. this study focuses on the suva planina mt. karst aquifer system and its “first” layer – epikarst. during the survey, an innovative methodology was employed, combining indirect methods like remote sensing with field techniques such as geomorphological research, hydrogeological and epikarst mapping, geophysical surveys, petrological/sedimentological research, and pedological studies. this combined approach yielded exceptionally good results. using satellite imagery (remote sensing) helped define the general groundwater flow and the distribution of epikarst on the eastern slopes of suva planina mt. the epikarst potential (e) map created, guided further detailed field mapping, improving the understanding of the area's geology and geomorphology, and identified locations for geophysical surveys and sampling. field geomorphological research refined the distribution and characteristics of the epikarst, with hydrogeological mapping on benchmark profiles providing on-site data. four categories of epikarst were identified. geophysical surveys using vertical electrical sounding offered insights into fractured and karstified zones up to 30-100 metres deep. petrological research identified limestone types, while pedological analyses defined soil types and geochemical properties, highlighting the soil and epikarst's role in altering infiltrating water quality. continued multidisciplinary research on suva planina mt. is essential for understanding groundwater systems. enhanced geophysical methods and pre-field drone surveys are recommended for future studies, along with increased soil sampling from areas of diverse vegetation. typically estimated to be several metres up to 10­15 metres (klimchouk, 2000, 2004). there are many specific methods for researching the karst (epikarst) such as (petrović, 2020a; stevanović, 2015; goldscheider & drew, 2007): speleology, karst hydro­ logy/hydrogeology, karstology, speleobiology, cave diving (speleodiving), etc. here, we present integrated methods for surveying karst (specifically epikarst), which include remote sensing, geo­ morpho logical research, geophysics survey, hydrogeology and epikarst mapping, petrology/sedimentological research, and a pedological survey. these integrated methods were used to define the epikarst of the eastern part of suva planina mt. and to explore the formation and function of this specific layer in the aforementioned setting. 2. characteristics of the study area suva planina mt. is located approximately 230 km se of belgrade. the name of the mountain (suva = dry) originates from the fact that there are only a few springs on the higher slopes of the massif, and only two springs discharge almost all year round: bojanine vode (860 m a.s.l.) and rakoš (1280 m a.s.l.). the karst aquifer system of suva planina mt. is formed article history: manuscript received: july 26, 2024 revised manuscript accepted: november 05, 2024 available online: january 30, 2025 keywords: epikarst, applied research, karstification, suva planina mt., se serbia mailto:branislav.petrovic@rgf.bg.ac.rs g eo lo gi a c ro at ic a 32 geologia croatica 78/1 in the limestones of middle and upper jurassic and lower cretaceous age on the north­eastern slopes of the mountain (petrović, 2020a, b; marinović & petrović, 2021; petrović et al., 2023; petrović & marinović, 2023). the local faults provoked the enhancement of the karstification process in the limestone and dolomite, and the groundwater flow has been directed transverse to the original nw­se direction (stevanović, 1991; petrović, 2020a, b). on suva planina mt., peć cave in barski hrid and orlovica cave in ostrovica, north of the area that was the subject of detailed investigation works, as well as two small jamas (shafts): jama in the konjsko area and ledenica in the ždrebica area (on the western slope of suva planina) were found (petrović, 1976). underground karst formations are present on the eastern slopes of suva planina mt., but are dissimilar to those on the northern and western vertical limestone cliffs. the underground karst phenomena discovered in the research area are the prosek jama and the peč cave, in the area of the village of bežište (bukovica area) (petrović, 2020a; petrović, 2023). additional karstification provided further and finer division of the groundwater flow and resulted in quite a few orifices of the aquifers in the foothills of suva planina mt. (petrović & marinović, 2021; petrović et al., 2023). karst springs that originate from the carbonate rocks of suva planina mt. (fig. 1) and are used for the public water supply include: mokra, divljana, gornjekoritničko, bežište, ljube­ rađa, lazinje, sopotnica i and sopotnica ii, gornjedušničko and golemo. however, the bojanine vode, vrgudinac, ropot, provaljenik, izvor, pk proseka, and rakoš springs have also been used for water supply, but their quantity and sometimes the quality are not always adequate. during the 1980’s, a few of the karst springs were captured for a water supply to niš city: mokra (qavg ≈ 550 l/s), divljana (qavg ≈ 450 l/s), ljuberađa figure 1. location of the study area and hydrogeological map (adapted from petrović, 2020b). g eologia c roatica 33petrović et al.: epikarst of the eastern part of suva planina mt.: a new perspective defined from an integrated survey (qavg ≈ 850 l/s), and golemo (qavg ≈ 300 l/s), while gornje­ dušničko (qavg ≈ 200 l/s) has been captured for a water supply to the town of gadžin han. the recharge of aquifers is precipitation based with effective infiltration estimated up to 350 mm (stevanović, 1991, 1994; petrović, 2020b). the research area has a moderate­continental climate with characteristically long and cold winters and relatively warm summers. the average annual precipitation for the period 1991–2018 is 593.8 mm (according to data from the republic hydrometeorological institute of serbia, analysed in petrović, 2020b). the average multi­year air temperature for the same period is +12.6 °c. 3. methodology during the study, an innovative methodology of a combination of indirect survey methods (remote sensing) together with field survey (geomorphology research, hydrogeology and epikarst mapping, geophysics survey, petrology/sedimentology research and pedology research) was used, indicating that the combination gives extremely good results. field surveys and sampling have been conducted in several localities within the research area: rakoš spring, bukovica (area between peč cave and bežište), bežište village, mokra village and divljana village (figs. 2 and 3). the application of remote sensing of satellite images (landsat 8 image courtesy of the u.s. geological survey) and analysis of the rupture structure of the terrain taken from the basic geological map (bgm) of sfr yugoslavia, sheet bela palanka vujisić et al. (1971), served to define the presence of ruptures and as a basic preparation for field research of the epikarst. the interpretation of landsat 8 was performed with a channel 5, 6 and 7 combination (won­in & charusiri, 2003), as well as with a channel 7, 6 and 2 combination (gisgeography, 2024). the raster files were filtered with an image enhancement tool to improve the quality. contrast enhancement of "raw" images was performed by selective linear transformation of the original pixel values. the colour­ composite images allowed for easier observation of linear elements and the creation of a map of the rupture assembly, with the use of the convolution function in filtering the images (arcgis, 2024). also, spatial filtering of recordings was performed using the process of highlighting line elements with an edge enhancement tool to improve the perceptibility of ruptures. remote detection was also applied during vegetation analysis (agricolus, 2024), by determining the normalized difference vegetation index – ndvi, as well as by defining the normalized moisture deficit index – ndmi. as part of the epikarst research, analysis of the geomorphological charac­ teristics of the terrain was performed (e.g. of the topography of the terrain, and of the digital elevation model – dem 10 m resolution). furthermore, analysis of the geological composition was performed from the aspect of rock susceptibility to karstification as well as analysis of soil and vegetation as factors influencing the epikarst (petrović, 2020b; petrović et al., 2022). these analyses resulted in the creation of layers (n – vegetation ndvi; p – soil protection; s – slope; k – degree of karstification) that were used for designing the map of po tential for epikarst development – e map. the map of potential for epikarst development was created according to the formula: e=2n+p+2s+3k (petrović, 2020b; petrović et al., 2022). the final map has four categories of potential for epikarst development: 1 – low, 2 – medium, 3 – high and 4 – very high. geomorphological research was carried out in several stages, during which the existence, number, arrangement and size of large geomorphological objects such as sinkholes, uva­ las, jamas and caves within the research area were determined. the recording of the coordinates of phenomena and objects on the ground was carried out using the global positioning system (gps), while the dimensions of the objects were determined using a laser range finder (leica disto lite 5). geophysical surveys were undertaken using the electrical method, applying the technique of vertical electrical sounding (ves). the ves technique gives good results when examining horizontal or sub­horizontal layers (reynolds, 2011). the karst receives more water in the case of zones with higher resistivity, while it receives less water in the case of zones with lower resistivity. zones with low resistivity are more karstified, while zones with high resistivity are less karstified (veress et al., 2023). karst phenomena can be predominantly air­filled and then have high resistivity (e.g., >1000 ωm) or partly or totally water­filled with resistivity between 60 ωm to 1000 ωm. depending on the ionic concentration of the groundwater in the karst structures (features), which are partly or totally water­filled, they may have resistivity values varying from low (e.g., 60­100 ωm) to relatively high (e.g., 100­250 ωm), in comparison to the host rock (e.g., >2000 ωm for non­karst limestone) (torrese, 2020). the ves technique is applied to determine the change of electrical resistivity with depth using the schlumberger array. the schlumberger array is mostly used in vertical electrical sounding for its better depth penetration. in this array, four electrodes are placed in a line around a common midpoint. the two outer electrodes (a and b) are current electrodes, and the two inner electrodes (m and n), are potential electrodes placed close together. to obtain the maximum depth penetration in the ves procedure, the distance between the potential electrodes does not change and the current electrodes are moved away, thus increasing the depth penetration. as a result of the application of this technique, electrical sounding diagrams were obtained. these diagrams are displayed using a bi­logarithmic diagram where the electrical resistivity is given as a function of the half­ distance of the current electrodes (ab/2). during the survey, the distance between the current electrodes (ab/2) ranged from 30 m to 300 m. the rock samples, marked rs1 to rs7, taken during field investigations within the research area were subjected to petrological analysis. of the seven rock samples, three were taken from the peč cave and its immediate surroundings, while four others were taken from specific locations within the research area (figs. 2b and 3). the rock samples were taken from the surface of the terrain, except for sample rs2 that is taken from the interior of the cave. sample rs1 is from the surface above the cave peč and sample rs3 was taken about 100 metres from the entrance of the cave. two samples rs4 and rs5 were taken from the surface of the terrain between the peč cave and bežište karst spring – bukovica area (fig. 2b) and one sample rs6 was from the exposed limestone g eo lo gi a c ro at ic a 34 geologia croatica 78/1 brand polarizing microscope (type bh50). micropaleontological analysis of thin­sections included the determination of for­ amini fera and other microfossil content. within the framework of land cover (soil) research, parameters of soil samples (s1­s8) were determined in the laboratory: soil moisture, mineral composition, soil organic matter content, as well as the physico­chemical processes that occur within it, influencing the changing properties of surface (ground) waters. the soil samples were taken from the following locations: s1 – from the interior of the peč cave, sample s2 was taken about 100­150 metres from the entrance to the cave (fig. 2b). two samples (s3 and s4) were taken in the bukovica area between the peč cave and the bežište karst spring (fig. 2b) and one sample s5 was from immediate vicinity of the bežište karst spring. sample s6 was taken between the villages of gornja koritnica and divljana (fig. 3). samples s7 and s8 represent a soil from the immediate surroundings of the divljana karst spring and the mokra above the bežište karst spring. the sample rs7 represents a limestone rock from the immediate surroundings of the mokra spring and its hinterland (fig. 3). during macroscopic examination, the samples were tested with diluted hydrochloric acid (hcl). to determine the calcite content in these carbonate rocks and apply the appropriate classification, a quick method for determining the caco3 content in the rock – calcimetry – was applied. the mineral composition of the studied sedimentary rocks was determined by examining the petrographic preparations on a polarizing zeiss microscope for transmitted light coupled with a zeiss axiocam 208 colour digital camera. examinations of petrographic samples of sedimentary rocks included the determination of structure and grain orientation, as well as some of the textural characteristics. all analysed samples of limestone were first defined optically, which determined the direction of further study. micropale­ onto lo gical examinations were carried out via examination of thin­sections (transparent petrographic/micropaleontological preparations). analyses were performed using an olympus figure 2. a) the e map of the area with locations of the geophysical field surveys: rakoš spring (up) and bukovica area (down). b) the e map of the bukovica area and bežište karst spring area with sampling locations of soil (up) and rocks (down). g eologia c roatica 35petrović et al.: epikarst of the eastern part of suva planina mt.: a new perspective defined from an integrated survey spring, respectively (fig. 3). in addition, the objectives of the physico­chemical compositional research of the soil were to: – perform technical analysis of samples and determine the amount of organic matter present – determine whether the soil is contaminated with any heavy metals. the determination of the content of all major and trace elements that make up the soil was carried out at the labo­ ratories of the faculty of chemistry, university of belgra de. standards srps b.h8.390/1987 and iso 1171 were used for the preparation of samples for technical analysis (moisture and ash content) (smiljković, 2019; petrović, 2020b). ele­ mental analysis determined the content of hydrogen, nitrogen, sulphur, and organic carbon. organic carbon was analysed after the removal of carbonates with diluted hydrochloric acid (1:3 v/v). measurements were carried out on the vario el iii, chnos elemental analyzer, gmbh apparatus. sample preparation for the analysis of macro­ and microelements in soil was performed using microwave digestion (ethos1­ advanced microwave digestion milestone). the content of macro­ and microelements was determined by optical emission spectrometry with inductively coupled plasma (icp­oes) on a thermo scientific cap 6500 duo icp instrument (thermo fisher scientific, cambridge, uk). standards for the pre­ paration of the standard series were used during this process (multi­element plasma standard solution 4, specpure®; silicon, plasma standard solution, specpure®, si 1000 µg/ml; ss­low level elements icv stock 10 mg/l: ag, al, as, ba, be, cd, co, cr, cu, mn, mo, ni, pb, sb, se, th, tl, u, v, zn). hydrogeological and epikarst mapping was carried out in parallel with the geomorphological research, after geophysical surveys. the mapping included defining the characteristics of the epikarst on open rock outcrops and cuts, where the thickness of the epikarst, its composition and area of distribution were determined, and data collected were prepared for correlation with facts already collected by remote sensing and with details presented on the map of potential for epikarst development (petrović, 2020b; petrović et al., 2022). figure 2. continued. g eo lo gi a c ro at ic a 36 geologia croatica 78/1 4. results and discussion remote sensing was used during the analysis and extraction of lineaments on the processed (rgb) combination raster 567 and 762, as well as when defining the ndvi and ndmi, which together helped in the formation of the map of potential epikarst development (fig. 2). the potential for epikarst development depends firstly on existing tectonic conditions (faults and cracks) and the increased influence of vegetation. the influence of the forest vegetation is through the work of the root system, the retention of other living things in the surface litter created from fallen leaves, and the increase of carbon dioxide content due to the unfolding of life processes and the process of decomposition of organic matter, as well as other chemical compounds that have a corrosive effect on the limestone in the basement. the e­map has 4 categories (figs. 2 and 3; 1 pixel=100 m): 1 – low potential, 2 – medium potential, 3 – high potential, and 4 – very high potential. surfaces of different potential categories for epikarst development are shown in four colours from green (low potential) to red (very high potential). in the e map the area of the terrain that shows a low potential for the development of epikarst occupies only 1.5% of the area of exposed carbonate rocks in the research area, while the medium potential for the formation of epikarst represents 11.5% of the area. 53% of the exposed limestone area has a high potential for the formation and development of epikarst, and 34% is very high (petrović, 2020b; petrović et al., 2022). considering the size of the pixels it should be emphasized that the e map cannot be used independently to define the degree of real development of the epikarst, without further field research. therefore, the next step in the research was the mapping of the epikarst on open outcrops and cuts (fig. 4, a­d), when the thickness of the epikarst, its composition and area of distribution were determined. for the purposes of defining the degree of karstification and epikarst evolution in the research area of the suva planina mt. four categories of this subsurface layer were distinguished (fig. 4, 1­4). categories were made primarily according to the thickness of the zone, then according to the thickness of the soil layer located on the surface and finally the presence and type of vegetation. figure 3. the e map of the area with locations of geophysical field surveys, rock and soil sampling around mokra (up) and divljana (down) karst springs. g eologia c roatica 37petrović et al.: epikarst of the eastern part of suva planina mt.: a new perspective defined from an integrated survey the first category (fig. 4­1) is poorly developed epikarst up to 50 cm thick, sometimes up to 1 m, on which the presence of cracks filled with soil can be observed, the thickness of the soil layer is up to 10 cm, when it is present. the second category (fig. 4­2) is developed epikarst characterized by the presence of a significantly thicker layer of soil on the surface of 10 to 30 cm (rarely up to 50 cm), while the epikarst layer is about 1­1.5 metres thick, wider cracks and caverns (centimetre dimensions) can be observed, and which are often not fulfilled. the third category (fig. 4­3) is medium­developed epikarst characterized by a significant thickness of the base layer, up to 3 metres, but it is most often 1.5 to 2 metres thick, the soil is of varying thickness from 10 to 30 cm, it can also be absent on smaller areas (the epikarst is bare), cracks and channels are common, and are often filled with secondary material. the fourth category (fig. 4­4) is extremely well developed epikarst that has all the characteristics of the previous category, only the thickness of the epikarst is always over 3 metres. categories separated and created with the help of remote sensing methods coincide with mapping and field research to a lesser degree than expected. the inconsistency of the results obtained using remote sensing and field surveys exists for several reasons. primarily, the pixel size on the map (100 px) is larger than necessary for this level of research, because the local epikarst and its degree of development can change at distances of less than 50 m. it is necessary to have more detailed geological mapping than the 1:25 000 maps used here. the thickness of the epikarst in the survey area was defined by the ves technique as well. measurements using the ves technique were done on locations that have been chosen based on geomorphological and hydrogeological surveys. the ves was done on locations rakoš, bukovica, divljana and mokra. in the rakoš area (fig. 2a), the distance between the current electrodes (ab/2) was 30 m. in the bukovica area the distance between the current electrodes (ab/2) was 30 m and 110 m (fig. 2b). the distance between the current electrodes (ab/2) in mokra and divljana locations was 50 m to 300 m (fig. 3). the ves measurements on rakoš were done along profiles ves1–ves5 (fig. 2a). the results in points ves1, ves2 and ves3 show that the measurement is done in the fault zone (fig. 5a). this zone is without a diluvial overlay with high values of specific electrical resistivity from the surface to a depth of over 2 m. the measurement points ves1 and ves2 are located over the fault zone on a relatively raised block with a diluvial layer and debris material in it. the measurement points ves4 and ves5 are located on the raised flank of the fault and ves5 is located the farthest from the fault zone. the data from ves5 show that diluvium and clay are found in this part, which are washed closer to the fault and eroded onto the flank that descends. the results of ves measurements at the rakoš indicate that there are zones of lower and higher resistivity. in the shallowest part of the terrain, the resistivity is high indicating that this part of the terrain contains limestone rubble in a dried clay matrix. the change by the depth of high and low resistivity (ves1–ves4) is related to the change of dry larger limestone blocks and degraded limestone belts with water, or clay as a filling. the ves5 measurements show that such heterogeneity of the limestone is not visible, but beneath the clay layer lies weakly cracked limestone, to a depth of almost 20 m. the results of a geophysical survey on rakoš along the profile ves1–ves5 (fig. 5a) shows the layer consisting of decomposed and altered limestone rock material (breccia and debris) and soil, which in this case represents the epikarst. the thickness of the epikarst at the rakoš ranges from 3 to 15 metres. at the bukovica location, the ves measurements were undertaken along profiles ves6–ves9 (fig. 2a). the results in points ves6, ves7, ves8 and ves9 show that the measurement is also undertaken in the fault zone (fig. 5b). the results along the profile ves6–ves9 indicate that the resistivity increases with depth and that there is a dry system of cracks, pits and caverns below the surface. the results of figure 4. the mapping of the epikarst on open outcrops and cuts with degree of epikarst development: mapping of the epikarst on open outcrops and cuts – a), b), c) and d). epikarst categories: 1, 2, 3, 4; legend: s – soil, e – epikarst, k – karst. g eo lo gi a c ro at ic a 38 geologia croatica 78/1 ves on the bukovica profile show the layer consisting of decomposed and altered limestone rock material (breccia) and soil, which in this case represents the epikarst. the thickness of the epikarst at the bukovica ranges from 1.5 to 9 metres (fig. 5b). in this area, the epikarst overlies a well karstified limestone in which there is a system of dry cracks, caverns, and larger channels. at the mokra location, the ves measurements were made at three points ves10, ves11 and ves12 (fig. 3). this research indicated that the base of the karstification is located at >95 m depth. the results of ves at point ves10 show that there is dry karstification beneath the examined terrain (fig. 5c). the measurement point ves11 is located exactly above the karst spring and the results of the measurements indicate that there is cracked limestone below. at the level of the karst spring, at a depth of about 15 m, the influence of groundwater appears. the thickness of the epikarst at the mokra site ranges from 0.5 to 4 metres. finally, at the divljana location, the ves measurements were undertaken at three points ves13–ves15 (fig. 3). this research established that the base of the karstification depth in this area is around 100 m. the results of ves at point ves13 show that there is dry karstification below the examined terrain (fig. 5d). the measurement point ves14 is located above the karst spring and the results of the measurements indicate that there is fissured limestone with groundwater. the thickness of the epikarst at the divljana site ranges from 0.5 to 4 metres. the examined samples of limestone are dark grey in colour and have a crystalline structure. the rock surfaces are often covered with white calcite scrums (up to 3 mm thick) and powdery limonite (rust colour). limestones are strongly tectonized, which was manifested by the appearance of white calcite cracks/wires. the sample from the bežište area (rs5) underwent strong recrystallization (fig. 2b). they are very hard and compact, breaking into pieces with rough fracture surfaces and sharp fracture edges. considering the textural features, we can note that oscillogram­type stylolitic seams marked by dark, non­carbonate minerals (ingredients) stand out. macroscopically, allochemical components can be ob­ serv ed. usually, the allochemical component is relatively fine­ grained, consisting of peloids and organic residues, with sections of macrofossils, with uniform dimensions of 2 to 5 mm in most of the samples. in addition, sections of circular, ellipsoidal shapes up to 1 cm in size could be noticed in some samples (fig. 6). structurally, the rocks correspond to flugel (2004): wackestone (rs1, rs4 and rs5) and pack­ stone (rs2, rs6, rs7) microfacies and grainstone (rs3). irregular dissolution structures are also developed in some rocks; fenestrae, that are filled with crystalline calcite (geopetal structure). cracks and microcracks filled with coarse­grained neocalcite are also present. bioclasts are represented by an association of marine microorganisms and their content is 20­ 25%. according to the content of allochems and orthochems (folk, 1959), the investigated sample rs1 corresponds to bio­ pelmicrite, rs2 corresponds to pelbiosparite, rs3 corre s ponds to biointrasparite/biopelsparite, rs4 and rs5 corres ponds to biomicrite, rs6 corresponds to biointramicrosparite and rs7 corresponds to fossiliferous micrite/biomicrite. figure 5. the interpretation of the ves measurements at selected locations: a) rakoš spring area, b) bukovica area, c) mokra karst spring area, d) divljana karst spring area. legend: 1 – alluvium; 2 – colluvium with clay infill; 3 – breccia; 4 – resedimented breccias (fault area); 5 – breccia (limestone); 6 – sands, marls, gravels, clays; 7 – highly karstified limestone; 8 – limestone; 9 – fault; 10 – ves location. g eologia c roatica 39petrović et al.: epikarst of the eastern part of suva planina mt.: a new perspective defined from an integrated survey limestones are characterized by an association of benthic foraminifera microfauna, with a low diversity of forms, and the detritus of shallow marine fossils. bioclasts could be repre­ sented by an association of marine microorganisms and their content is up to 25%. the chambers of foraminifera are filled with crystalline calcite. some of the microfossils have been determined (fig. 6): debarina cf. hahounerensis fourcade, raoult & vila, novalesia sp., pseudocyclammina sp., vercorsella sp., nautiloculina sp. the sedimentological interpretation based on the analysis of the available investigated limestones of suva planina mt. shows that they were created in a marine environment of the very shallow subtidal and slightly deeper intertidal zones. the origin of these limestones is most probably related to the outer edge of the carbonate platform, with low water energy, with a transition to less protected parts of the platform (lagoon). based on the biostratigraphic considerations of the entire determined association of foraminifera, the studied limestones correspond to the upper jurassic (rs2) and lower cretaceous periods and are related to shallow to slightly deeper subtidal depositional environments. considering that the calcite content in the samples rs1 and rs2 exceeds 97%, it is not surprising that the karstification and the formation of channels and caverns of metre dimensions are very pronounced. it can also be concluded that the compo­ sition of the rocks on the eastern slope of suva planina mt. favours the emergence of the karstification process and its rapid progress, especially in combination with the tectonic movements that caused the rise of the anticline and cracking of the limestone layers, thus the emergence of epikarst on this terrain is not in question. the somewhat lower percentage of calcite in some samples was also reflected in the degree of karstification within the cretaceous rocks, which make up part of the terrain hypsometrically lower than the peč cave, as well as the terrain that forms a large part of the mokra, divljana, gornja koritnica and bežište springs catchment area. pedological research was initiated as part of the mapping process when basic data on the presence and thickness of soil were collected. samples for geochemical characterisation (s1­ s9) were collected from specific locations on the eastern slopes of the suva planina mt. (figs. 2b and 3). the technical analysis of 8 soil samples (s1­s8) and one rock sample of limestone (s9) were conducted (fig. 7), determining the quantity of organic matter (organic pollutants), and specific organic­geochemical parameters (smiljković, 2019; petrović, 2020b). the level of contamination (fig. 8) with heavy metals was defined according to serbian legislation (official gazette rs, 2018). the moisture content in the soil samples ranges from 2.62% to 7.72%, while in the reference sediment – s9 it is only 0.10%, which may indicate the absence of hygroscopic components that retain moisture. this assumption is also confirmed by the result showing that the sediment is composed of 99.90% carbonates. the ash content ranges from 62.94% to 90.71% indicating that the soil is expected to be predominantly mineral. the sediment has the lowest ash content compared to other samples, 56.83%, which can be explained by the fact that during heating to over 800 °c, carbonates degrade into oxides with the release of co2. carbonate content values range from 17.46% to 80.40%. a higher carbonate content is noticeable in figure 6. some of the microfossils determined during the research: a) sample rs4 in the centre debarina cf. hahounerensis; b) rs5 – in the centre vercorsella sp. c) rs5 – association of novalesia sp., debarina cf. hahounerensis and fossils of a shallow sea; d) sample rs6 – microfossils of a shallow sea – pseudocyclammina sp., bivalvia and other micromolluscs. g eo lo gi a c ro at ic a 40 geologia croatica 78/1 samples s1­s4, especially in sample s2, which can be explained by the fact that this sample was taken inside the peč cave, and the soil there is influenced by the erosion of limestone rocks and decomposed calcite ending up in the soil. the percentage of hydrogen and nitrogen ranges from 0.58% to 1.74% and from 0.11% to 0.86%, respectively. at locations s5­s8, a significantly lower carbonate content is observed compared to samples from the peč cave and bukovica locations. the cause can be found in the thicker layer of soil present at these locations (s5 and s6), as well as in the fact that pliocene and oligocene sedimentation of clastic materials was later eroded by weathering processes from the hypsometrically lower parts of suva planina mt., where the sampling locations (s6­s8) were situated. the nitrogen content positively correlates with the organic carbon content, indicating that nitrogen is bound to organic matter, which is present in the soil composition (smiljković, 2019; petrović, 2020b). the total carbon (c) content after carbonate removal ranges from 0.98% to 12.42%. a higher percentage of total carbon (c) in sample s1 is associated with a greater amount of organic matter, indicated not only by the increased organic carbon content but is also visually observed, as these samples had significantly more plant and animal remains. the sulphur content in all samples is below the detection limit, indicating the absence of sulphate and sulphide minerals, as well as the absence of contamination with sulphur organic compounds. the values of organic carbon content (corg) range from 0.38% to 4.92%. it was not possible to determine the organic carbon content in the sediment sample, as it is almost 99.9% carbonate that dissolved during acidic digestion. the main mineral components in the soil samples are aluminosilicate, likely represented by clay minerals, as well as si, al, and fe oxides. an exception in this regard is the s2 sample taken inside the peč cave, where ca (in the form of carbonates) dominates, and which is compositionally most like the reference sediment. except for s2, of all the macroelements in the soil samples (fig. 7), silicon is the most abundant, followed by aluminium, indicating that the main mineral component in the samples is aluminosilicates, likely represented by clay minerals. in the soil samples, the concentration of calcium has a wide range (from 3.917 to 149.046 mg/g), which is consistent with the extremely high concentration of carbonates. the concentration of magnesium in the soil samples is 110 times lower than the concentration of ca in the sediment s9 sample, indicating that the rock sample is almost entirely composed of caco3. the concentrations of mg and si are similar in sample s9, sug gest­ ing that besides carbonates, some mg may also be present in the form of silicates. the concentration of iron in s9 can be considered significant, although it is only at 345.87 μg/g. all other macro­ and microelements in the rock sample have signi­ ficantly lower contents <300 μg/g. the concentrations of trace elements: as, cd, co, cr, cu, ni, pb, se and zn were compared (fig. 8) with the permissible metal concentrations in sediments and soil (official gazette rs, 2018). basic correlations of the analysed ele­ ments have also been completed (supplement 1) (smiljković, 2019). the concentration of as is above the permissible value in samples s4­s8, with the concentration in samples s6 and s7 exceeding the remediation values, while it was not detected in the sediment. arsenic did not show a correlation with any of the macro­ and microelements, nor with the content of organic carbon, indicating that it is likely partially present in the orga­ nic and partially inorganic components of the soil. the concen­ tration of cd is above the permissible value in all samples except in sample s6, while it was not detected in sample s9. the concentration of co is above the permissible value in all samples. concentrations of cr were below the permissible concentration for soil in all samples. the concen tration of figure 7. the macroelements in the soil (s1-s8) and rock (s9) samples. g eologia c roatica 41petrović et al.: epikarst of the eastern part of suva planina mt.: a new perspective defined from an integrated survey cu is above the permissible value only in sample s2. cu has shown a remarkably positive correlation with ca and a solid one with carbonates (supplement 1), indicating that it is mainly present in the form of carbonates, i.e. natural basic carbonates such as malachite, cu2(oh)2co3, and azurite, cu3(oh)2(co3)2. therefore, the elevated con cen tration of cu in sample s2 can also be explained by its geogenic ori gin, as the high concentration of this trace element was observed in the sediment itself, represented by nearly pure carbonate, which was used as a reference sample. the concen tration of ni is above the permissible value in all soil samples except for s2, while in the sediment, it is an order of magnitude lower. based on the results of the correlation matrix (smiljković, 2019), a statistically significant positive correlation between ni content and fe content, as well as the content of these two elements with co content, was observed. considering that these are siderophile elements, the elevated concentration of ni is most likely of geogenic origin. the concentration of pb is above the permissible value only in sample s4. the concentration of se is above the permissible value in all samples but in samples s5 and s8 was not detected. the concentration of zn is above the permissible value in samples s2 and s4. the results of soil analyses have shown that there are many trace elements in the composition of the soil, which can enrich the mineral composition of the water infiltrating through the soil on its way to groundwater and yielding at karst springs. most of them are associated with the presence of clayey (aluminosilicate) particles that constitute the soil. however, analyses of the chemical composition of groundwater from karst springs (mokra, divljana, gornjekoritničko, bežište) have shown that the content of mineral substances significantly reflects an influence of carbonate rocks through which water percolates and circulates on its way to the point at which groundwater emerges from the aquifer (petrović, 2020b). therefore, the soil together with epikarst (because sometimes the boundary is not visible) can be regarded as a medium for the initial alteration of the quality of infiltrated surface water (usually in the form of rain and melted snow). these alterations are fragmentary, in other words, alterations may start in the soil, and some may occur in the epikarst layer, but the most substantial alteration of karst groundwater quality occurs within the saturated zone of the karst aquifer – limestones (dolostones). conclusion the results obtained using satellite imagery (remote sensing) have helped in defining the epikarst at the regional level (eastern slopes of the suva planina mt.). the designed e (epikarst potential) map aided in defining the regional development of the epikarst and served as a basis for more detailed mapping of the epikarst during field research as well figure 8. the concentration of trace elements in the soil samples (s1-s8) and rock sample (s9). g eo lo gi a c ro at ic a 42 geologia croatica 78/1 as in a better understanding of the area’s geology and geo­ morphology and defining locations of geophysics surveys and rock and soil sampling locations. geomorphological field research methods provided a better understanding of the degree of karstification, thus leading to a better definition of the distribution of the epikarst and its characteristics in the eastern slopes of suva planina mt. for defining the characteristics of the epikarst, (hydro) geological mapping was conducted on benchmark profiles defined according to the e map altogether with geomorpho­ logical field research. basic characteristics of the epikarst were defined on site, including the thickness and surface areas on exposed outcrops and sections. four categories of epikarst were identified. it is advisable to use other remote sensing methods as well, such as the use of unmanned aerial vehicles, especially in parts of the terrain with a particular potential for the formation of epikarst, characterized as inaccessible for visits and on­site measurements. geophysical surveys were conducted at four locations, with a total of 15 probes, within the research area using the geoelectric method, employing the vertical electrical sounding (ves) procedure with a schlumberger­type electrode display. the collected data provided new insights into the thickness and distribution of fractured and karstified zones up to a depth of 30 (100) metres, as well as in defining the thickness of the epikarst in areas subjected to geophysical surveys, thus helping in extrapolation of collected data of single point assessment conducted during mapping. petrological/sedimentological research precisely defined the types of limestone rocks at selected locations, each repre­ senting one type of carbonate rocks on the eastern slopes of the suva planina mt. pedological analyses allowed better definition of the soil types based on the macrocomponent content of soil, geo che­ mical characterization of soil and pollution, as well as the definition of organic­geochemical parameters of that, in combination with epikarst, the very first layer which at the same time protects, changes and sometimes could pollute infiltrated water. therefore, the soil along with the epikarst (since the boundary is sometimes indistinct) can be considered as a medium for the initial alteration of the quality of infiltrating surface water (typically in the form of rain and melted snow). these alterations are fragmentary, and changes may begin in the soil or occur within the epikarst layer, but the most signi­ ficant impact on karst groundwater quality takes place in the saturated zone of the karst aquifer. research on the eastern slopes of suva planina mt. should continue and extend to the entire mountain massif. this comprehensive approach, incorporating multidisciplinary and detailed geological research that comprises geomorphology, geophysics, hydrogeology, sedimentology and pedology, is necessary to understand the catchment area of springs, as well as the circulation patterns of groundwater in this complex hydrogeological system. technical constraints during the 2018­2020 field investi­ gations limited the number of vertical electrical sounding surveys, indicating a need for a broader application of this technique in future studies across other locations on suva planina mt. utilizing geoelectric tomography and/or ground­ penetrating radar could provide a more comprehensive picture of the epikarst development and the unsaturated zone within the karst aquifer system of suva planina mt. to accurately map the distribution of epikarst on the eastern slopes, an increased density of mapping points is needed. pre­field drone surveys should be conducted to identify reference profiles in less accessible areas. enhancing soil geochemical characterization requires increasing the number of samples from more reference profiles. these profiles should overlap with those used for defining epikarst characteristics. future soil sampling campaigns should focus on areas with noticeable changes in vegetation type and density. acknowledgement the authors would like to thank the ministry of science, technological development and innovation for providing resources under contract no. 451­03­66/2024­03/200126 and contract no. 451­03­65/2024­03/200126. the authors would also like to thank milena dunčić, m.sc., eng. of geology on the preparation of paleontological analyzes of limestones. references chen, z., auler, a.s., bakalowicz, m., drew, d., griger, f., hartmann, j., jiang, g., moosdorf, n., richts, a., steva­ novic, z., veni, g. & goldscheider, n. (2017): the world karst aquifer mapping project: concept, mapping procedure and map of eu­ rope.– hydrogeol j, 25, 771­785. https://doi.org/10.1007/s10040­016­1519­ 3 flugel, e. (2004): microfacies of carbonate rocks: analysis, interpretati­ on and application.– springer­verlag, berlin, heidelberg, new york, 976 p. http://dx.doi.org/10.1007/978­3­662­08726­8 folk, r.l. (1959): practical petrographic classification of limestones.– bu­ lletin american association petroleum geologists, 43, 1­38. goldscheider, n. & drew, d. (2007): methods in karst hydrogeology, international contribution to hydrogeology.– taylor & francis/balkema, london, 264 p. klimchouk, a.b. (2000): the formation of epikarst and its role in vadose speleogenesis.– in: klimchouk, a.b., ford, d.c., palmer, a.n. & dreybrodt, w. (eds.): speleogenesis: evolution of karst aquifers. national speleological society of america, huntsville, 261­273. klimchouk, a.b. (2004): towards defining, delimiting and classifying epikarst: its origin, processes and variants of geomorphic evolution, spe­ leogenesis and evolution of karst aquifers.– speleogenesis and evolution of karst aquifers, 2/1, 1­13. marinović, v. & petrović, b. (2021): stochastic simulation and predi­ ction of turbidity dynamics in karst systems. case study: mokra karst spring (se serbia).– review of the bulgarian geological society, 82/3, 222–224. https://doi.org/10.52215/rev.bgs.2021.82.3.222 official gazette of the republic of serbia (2018): no. 30/2018: regulation on limit values of polluting, harmful, and dangerous substan­ ces in soil. petrović, b. (2020a): intrinsic groundwater vulnerability assessment by multiparameter methods, a case study of suva planina mountain (se ser­ bia).– environ earth sci, 79, 85. https://doi.org/10.1007/s12665­020­ 8825­8 petrović, b. (2020b): the functioning and impact of epikarst oh the regi­ me, balance and groundwater quality of the eastern part of the suva pla­ nina mountain karst system [in serbian, abstract in english].– unpubl. phd thesis, university of belgrade, 305 p. https://doi.org/10.1007/s10040-016-1519-3 https://doi.org/10.1007/s10040-016-1519-3 http://dx.doi.org/10.1007/978-3-662-08726-8 https://doi.org/10.52215/rev.bgs.2021.82.3.222 https://doi.org/10.1007/s12665-020-8825-8 https://doi.org/10.1007/s12665-020-8825-8 g eologia c roatica 43petrović et al.: epikarst of the eastern part of suva planina mt.: a new perspective defined from an integrated survey petrović, b. (2023): the flow conditions in the epikarst zone of a karst aquifer. case study: suva planina mt., east serbia.– in: international scientific conference, man and karst 2022, september 12th ­ 17th, cu­ stonaci, italy. ragusa, 123­129. petrović, b. & marinović, v. (2021): application of the discrete au­ toregressive – cross­regressive moving average model for predicting the daily discharge values of mokra and divljana springs.– reports of the serbian geological society year 2020, 1 – 15. petrović, b. & marinović, v. (2023): quantitative and geochemical characterization of the mokra karst aquifer (se serbia) by time series analysis and stochastic modelling.– in: andreo, b., barberá, j.a., durán­valsero, j.j., gil­márquez, j.m., mudarra, m. (eds): eurokarst 2022, málaga. advances in karst science. springer, cham. https://doi.org/10.1007/978­3­031­16879­6_8 petrović, b., stevanović, z., marinović, v. & ignjatović s. (2022): prostorna analiza epikarsta u okviru karstnog sistema istočnog dela suve planina [spatial analysis of epiкarst within karst system of eastern part of suva planina mountain – in serbian].– in: xvi srpski simpozijum o hidrogeologiji sa međunarodnim učešćem. univerzitet u beogradu, rudarsko­geološki fakultet, beograd, 365­370. petrović, b., marinović, v. & stevanović, z. (2023): characteri­ zation of the eastern suva planina mt. karst aquifer (se serbia) by time series analysis and stochastic modelling.– environ earth sci, 82, 222. https://doi.org/10.1007/s12665­023­10911­5 petrović, j. (1976): jame i pećine sr srbije [jamas and caves of sr srbija – in serbian].– vojnoizdavački zavod, beograd, p. 511. reynolds, j.m. (2011): an introduction to applied and environmental ge­ ophysics, 2nd edition.– wiley­blackwell, 712 p. smiljković, ž. (2019): geohemijska karakterizacija zemljišta sa istočnih obronaka specijalnog rezervata prirode „suva planina“ [geochemical characterization of soil from the eastern slopes of the special nature reserve "suva planina" – in serbian].– unpubl. master thesis, univer­ sity of belgrade, 47 p. stevanović, z. (1991): hidrogeologija karsta karpato­balkanida istočne srbije i mogućnosti vodosnabdevanja [karst hydrogeology of the carpatho-balkanides of eastern serbia and water supply possibilities – in serbian].– university of belgrade, faculty of mining and geology, bel­ grade, 245 p. stevanović, z. (1994): karst groundwaters of carpatho­balkanides in ea­ stern serbia.– in: stevanović z. & filipović b. (eds.): ground­ waters in carbonate rocks of the carpatho­balkan mountain range. carpathian­balkan geological association, belgrade, 203­237. stevanović, z. (2015): karst aquifer – characterization and engineering.– springer, 692 p. https://doi.org/10.1007/978­3­319­12850­4 torrese, p. (2020): investigating karst aquifers: using pseudo 3­d electri­ cal resistivity tomography to identify major karst features.– journal of hydrology, 580, 124257. https://doi.org/10.1016/j.jhydrol.2019.124257 veress, m., deak, g. & mitre, z. (2023): the vertical electrical soun­ ding (ves) of the epikarst: a case study of the covered karst of the ba­ kony region (hungary).– acta carsologica, 52/2­3, 245­258. https://doi. org/10.3986/ac.v52i2­3.12149 vujisić, t., navala, m., kalenić, m., krstić, b., maslarević, lj., marković, b., buković, j. (1971): osnovna geološka karta sfrj 1:100.000, tumač za list bela palanka k34­33 [the basic geological map of sfry 1:100.000, explanatory text of the bela palanka sheet k34-33 – in serbian].– savezni geološki zavod, beograd, 69 p. won­in, k. & charusiri, p. (2003): enhancement of thematic mapper satellite images for geological mapping of the cho dien area, northern vietnam.– international journal of applied earth observation and ge­ oinformation, 4/3, 183­193. web sources: agricolus (2024): ndvi and ndmi vegetation indices: instructions for use, available at: https://www.agricolus.com/en/vegetation­indices­n­ dvi­ndmi/. accessed: 12/06/24. arcgis (2024): convolution function, available at: https://desktop.arcgis. com/en/arcmap/latest/manage­data/raster­and­images/convolution­fun­ ction.htm. accessed: 11/06/24. gisgeography (2024): landsat 8 bands and band combinations, available at: https://gisgeography.com/landsat­8­bands­combinations/. accessed: 21/05/24. https://doi.org/10.1007/978-3-031-16879-6_8 https://doi.org/10.1007/s12665-023-10911-5 https://doi.org/10.1007/978-3-319-12850-4 https://doi.org/10.1016/j.jhydrol.2019.124257 https://doi.org/10.3986/ac.v52i2-3.12149 https://doi.org/10.3986/ac.v52i2-3.12149 https://www.agricolus.com/en/vegetation-indices-ndvi-ndmi/ https://www.agricolus.com/en/vegetation-indices-ndvi-ndmi/ https://desktop.arcgis.com/en/arcmap/latest/manage-data/raster-and-images/convolution-function.htm https://desktop.arcgis.com/en/arcmap/latest/manage-data/raster-and-images/convolution-function.htm https://desktop.arcgis.com/en/arcmap/latest/manage-data/raster-and-images/convolution-function.htm https://gisgeography.com/landsat-8-bands-combinations/ g eo lo gi a c ro at ic a 44 geologia croatica 78/1 supplement 1. – pearson correlation matrix of soil samples analyses. www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the brina caves (pećine u brini), including the east, west and the small cave, located 4 km east of drniš, yielded one of the largest collections of alpine marmot (marmota marmota linnaeus, 1758) bone remains in croatia, with the east brina cave being the largest site in the dalmatian part of croatia. the alpine marmot skeletal remains were collected from the late pleistocene deposits in the brina caves during excavations conducted by mirko malez from 1960 – 1961, and from 1968 – 1970 (malez, 1963a, 1963b, 1970, 1971a, 1971b, 1975). besides alpine marmot remains, abundant late pleistocene vertebrate skeletal and dental material was recovered, along with the first palaeolithic artifacts found in the dalmatian area (malez, 1963a). marmots are the largest members of the sciuridae family and the second largest representative of rodentia after beavers. of the 15 species in the genus marmota, nine are found in europe and asia, while the remaining six species inhabit north america (armitage, 2013). the evolution of marmota began during the late miocene, about 10 million years ago in north america, and spread into eurasia afterwards (erbajeva & alexeeva, 2009). during the pliocene, eurasia became a centre for marmot diversification (menén­ dez et al., 2023), extending their range into eastern europe by the end of the pliocene (erbajeva & alexeeva, 2009). in the early pleistocene, marmots were extremely rare in europe and were seldom recorded at fossil sites, such as those in france (clot, 1975), austria (maul, 1990), georgia (tappen et al., 2002), and croatia (malez & rabeder, 1984; paunović & rabeder, 2000). the only exception is sierra de atapuerca in spain (estraviz­lópez et al., taphonomy of the alpine marmot (marmota marmota) remains from the late pleistocene deposits of the east brina cave, croatia ankica oros sršen1, rahela šanjek2, vibor novak1,* 1 croatian academy of sciences and arts, institute for quaternary paleontology and geology, ante kovačića 5, 10000 zagreb, croatia; (*corresponding author: vnovak@hazu.hr; aos@hazu.hr) 2 nova ulica 32, jalkovec, 42000 varaždin, croatia; (rahela.sanjek@gmail.com) doi: 10.4154/gc.2025.11 abstract the late pleistocene deposits of the east and west brina caves near drniš have yielded one of the largest collections of alpine marmot (marmota marmota linnaeus, 1758) remains in croatia. a total of 425 skeletal remains were recovered, with 411 originating from the east brina cave. taphonomic analysis of this assemblage reveals that multiple factors influenced the accumulation and preservation of marmot remains. while natural mortality, most probably, was the primary cause, secondary agents such as predation by small carnivores, particularly martens and foxes, played a significant role. additionally, a small number of bones bear cut marks, suggesting the occasional human exploitation of alpine marmots by palaeolithic hunters. bone surface modifications indicate that many remains were exposed before burial. these finds provide insights into the late pleistocene alpine marmot ecological dynamics, and human subsistence strategies in southeastern europe. 2021). during the middle pleistocene, there was a slight increase in the occurrence of marmot remains in spain and france, although they were still rare compared to other rodents (estraviz­lópez et al., 2021), as well as in italy and romania (paleobiology database, 2025). the habitat of late pleistocene marmota marmota was widespread across europe. their fossils have been found as far west as the cantabrian mountains in spain, across france and northern belgium, and as far south as italy, slovenia, croatia and montenegro. they also expanded eastward through slovakia, hungary, and moldova (malez, 1972; zimina & gerasimov, 1973; ramousse & le berre, 1993; toškan, 2007; borić et al., 2014; now data base, 2023). in croatia, the late pleistocene marmots have been discovered at 17 different localities, including the continental parts of the country: northwestern croatia, gorski kotar, and lika, as well as the coastal areas of istria and dalmatia (malez, 1972). although this would suggest a widely distributed habitat during the pleistocene, the amount of fossil remains is relatively low and fragmented at most localities (malez, 1995). the exceptions are the localities such as vindija, representing one of the richest marmot assemblages in southern europe, as well as the klek cave, šaftica cave, šandalja ii site, and the east brina cave, which is studied herein (malez, 1995; paunović et al., 2001; mauch lenardić & klepač, 2009). at present, marmots are not part of the recent croatian fauna, and it is assumed that they disappeared from this area either at the end of the late pleistocene or at the beginning of the holocene (mauch lenardić & klepač, 2009). article history: manuscript received: february 6, 2025 revised manuscript accepted: march 14, 2025 available online: june 30, 2025 keywords: alpine marmot, taphonomy, skeletal elements, brina caves, late pleistocene 2025 | 78/2 | 115–127 | 6 figs. | 5 tabs. | 2 plts. | mailto:vnovak@hazu.hr mailto:rahela.sanjek@gmail.com g eo lo gi a c ro at ic a 116 geologia croatica 78/2 although abundant literature exists on the ecology, morphology, and other aspects of marmots, taphonomic studies are still relatively rare. the purpose of this paper is to provide a taphonomic analysis, and to elucidate accumulation factors and post­depositional processes that affected the marmot fossil remains from the brina caves. 1.1. the brina caves the brina caves comprise three separate small caves (east, west, and small cave) and are located on the right­hand side of the čikola river 4 km southwest of the city of drniš (43°51'23"n, 16°06'29"e; fig. 1). the drniš area belongs to the north dalmatian hinterland. it is a karstic area surrounded by the promina mountains (1148 m a.s.l.) to the north, svilaja (1509 m a.s.l.) to the east, moseć (839 m a.s.l.) to the south, and the krka river to the west (hodžić & šorić, 2011). today, the brina caves are located 25 km from the coast, while during mis 2 the distance was 40 km (fig. 1). during the late pleistocene, the karstic hinterland was characterized by exposed karst and stands of trees, in contrast to the great adriatic plain (paunović et al., 2001; mauch lenardić et al., 2018; pilaar birch & vander linden, 2018). the entrances to the brina caves face south and are located at 250 m a.s.l. they were formed in thickly layered, light yellowish rudist limestones from the late cretaceous period (malez, 1963a). the largest of the three caves is the east cave, which is approximately 20 m in length and represents the central location within this cave complex (fig. figure 1. map showing the location of the brina caves near drniš, croatia, along with some known localities where late pleistocene marmot remains have been identified. red line represents sea level during mis 2. g eologia c roatica 117oros sršen et al.: taphonomy of the alpine marmot (marmota marmota) remains from the late pleistocene deposits of the east brina cave, croatia 2a, b). in the middle of the east cave, malez (1963b, 1975) logged a detailed profile (fig. 2c), recording the following stratigraphy: layer a – humus (5 – 15 cm thick), layer b – finely laminated yellow flowstone (10 – 15 cm), layer c – brown porous clay with scattered rock fragments (40 – 50 cm), layer d – red compact illite (15 – 20 cm), and layer e – olive green to dark grey illite (25 – 30 cm) (fig. 2c). within the layer e, a marmot burrow was detected during the excavations (fig. 2c, marked by “m”). in the topmost layer, rare recent bones from sheep and goats were recovered, along with the ceramic fragments of so­called "gradinska keramika". the flowstone covers fossiliferous illite layers, representing the oldest quaternary deposits in the cave. in layers d and e, evidence for the presence of late pleistocene humans was found, represented by charcoal, charred bones, and flint tools. according to malez (1975), all the collected artefacts belong to the upper palaeolithic, and the sediments were formed during the würm glacial. according to paunović et al. (2001), layer a is of holocene age, and layers b – d belong to the ois 2 (würm 3) (paunović et al., 2001; after malez, 1963a, b, 1975). based on the faunal assemblages, malez dated the east brina cave’s layers c – e and west brina cave layers d – e to the late pleistocene age (paunović et al., 2001; after malez, 1975). this was confirmed by radiometric dating (14c) on bison bone from the upper part of layer d in the west brina cave, that yielded an age of 18,388 years bp (malez, 1975). the fossiliferous late pleistocene layers (c, d, and e) comprise abundant fossil material, including: erinaceus sp. linnaeus, 1758, crocidura sp. wagler, 1832, lepus timidus linnaeus, 1758, oryctolagus cuniculus figure 2. the brina caves plan (a) with detailed profile (b) and transect (c) of the east cave (after malez, 1975). g eo lo gi a c ro at ic a 118 geologia croatica 78/2 linnaeus, 1758, ochotona pusilla pallas, 1769, marmota marmota linnaeus, 1758, cricetus cricetus linnaeus, 1758, arvicola scherman shaw, 1801, microtus sp. schrank, 1798, ursus spelaeus rosenmüller­ heinroth, 1794, mustela nivalis linnaeus, 1758, crocuta spelaea goldfuss, 1823, equus caballus fossilis linnaeus, 1758, asinus hydruntinus gray, 1824, sus scrofa linnaeus, 1758, cervus elaphus linnaeus, 1758, alces alces linnaeus, 1758, bovidarum gen. et spec. indet., capra ibex linnaeus, 1758, as well as abundant bird, amphibian, and snail finds (malez, 1963b). marmot burrows were recorded in the lowermost stratum e, which irrefutably proves that they lived in the east brina cave. 2. materials and methods a total of 425 skeletal remains were collected from the brina caves, of which 411 (96.7%) were found in the east brina cave (tables 1, 2). hence, we present here a taphonomic analysis of the east brina cave marmot assemblage, while the number of samples (14 remains) from the west cave is insufficient to offer statistically significant results. the material is stored at the institute for quaternary palaeontology and geology of the croatian academy of sciences and arts in zagreb. taxonomic identification and metrical analysis for long bones and skulls were already undertaken for 219 skeletal remains by tukša (2019). however, during the preparation of the master's thesis by one of the authors (šanjek, 2023), an additional 192 marmot skeletal remains were found in the institute’s collection. there are no available data about the excavation and sampling methods, and the bone remains do not have any provenance data, except that they were stored separately for the east and west caves. malez (1963a, 1975) recorded that the most of the marmot remains in the east cave were collected in the upper part of layer c, just below the flowstone (layer b). the remains included abundant limb bones, and two complete skulls, among other skeletal elements (table 2). based on the absence of small bone fragments and considering the site was excavated in the 1960s, we can presume that most of the skeletal remains were manually collected. skeletal analysis involved the detailed examination of each skeletal fragment and the documenting of anatomical, taxonomic and taphonomic information. anatomical and taxonomic identifications were made using a recent osteological reference collection of the institute for quaternary palaeontology and geology of the croatian academy of sciences and arts. the preservation category was based on the percentage of preserved bone compared to the original complete bone. the assessment was rounded to the closest percentage category: 10%, 25%, 50%, 75%, 90%, 95%, or 100%. poorly preserved bones were those below 75%, while bones with 75% or more preservation were considered well preserved. the relative age of the bones and teeth in the mandibles was determined by the criteria described in tomé (1998). based on the bone size, epiphysis fusion, teeth type and teeth wear, the remains were determined as being very juvenile (cub born in the spring of the same year), juvenile (cub from the previous year), and adult (3 years old and older). taphonomic analyses included careful bone examination under a 10x magnification hand lens and with a binocular microscope with camera (xtl­3400d, magnification up to 136.6x, camera dino­eye am4023x), followed by inter­ pretation based on the intensity and weathering type, mineral coating, burn marks, bite marks, gnawing, and cut marks. the types of taphonomic modifications were defined following behrensmeyer, 1978; behrensmeyer et al., 2003; lyman, 1987, 2008; fernández­jalvo & andrews, 2016; indra et al., 2022; nannini et al., 2022; roman­ dini et al., 2012; romandini et al., 2018; marques et al., 2018. since the purpose of this study was to determine the factors affecting the accumulation of marmots in the east brina caves, we separated taphonomic modifications into two table 1. most highly represented skeletal elements in the east brina cave and marmot age classes. element nisp mne adult juv very juv mni mandible 30 27 3 sin, 9 dex 7 sin, 4 dex / 16 ulna 29 29 2 sin, 2 dex 5 sin, 6 dex 5 sin, 9 dex 17 femur 29 24 4 sin, 2 dex 7 sin, 11 dex / 15 tibia 31 25 1 sin, 2 dex 4 sin, 1 dex 8 sin, 8 dex 14 table 2. identified skeletal elements of marmots in the east cave. nisp – number of identified specimens, mne – minimum number of elements, ra – relative abundance, fi – fragmentation index. nisp %nisp mne %ra fi cranium 12 2.9 5 29.4 0.4 mandibula 30 7.3 27 79.4 0.9 tooth 55 13.4 atlas 1 0.2 1 5.9 1 axis 1 0.2 1 5.9 1 cerv. v. 8 1.9 5 5.9 0.6 thorac. v. 15 3.6 13 6.4 0.9 lumb. v. 27 6.6 20 19.6 0.7 sacrum 2 0.5 2 11.8 1 caud. v. 10 2.4 7 2.2 0.7 sternum 1 0.2 1 5.9 1 rib 23 5.6 23 11.3 1 clavicula 8 1.9 8 23.5 1 scapula 11 2.7 10 29.4 0.9 humerus 23 5.6 19 55.9 0.8 radius 13 3.2 13 38.2 1 ulna 29 7.1 29 85.3 1 metacarpus 13 3.2 13 15.3 1 pelvis 36 8.8 13 76.5 0.4 femur 29 7.1 22 64.7 0.8 tibia 31 7.5 25 73.5 0.8 fibula 2 0.5 1 2.9 0.5 calcaneus 3 0.7 3 17.6 1 astragalus 2 0.5 2 11.8 1 metatarsus 13 3.2 13 15.3 1 phalanx 13 3.2 13 15.3 1 total 411 100 289 g eologia c roatica 119oros sršen et al.: taphonomy of the alpine marmot (marmota marmota) remains from the late pleistocene deposits of the east brina cave, croatia categories: weathering marks and predatory markings, to simplify the factors affecting accumulation. to achieve this, it was necessary to differentiate between marks obtained during predation and those developed during deposition. this approach also accounts for additional biotic markings (non­ related to predation or scavenging), including etching by plant roots, algae, fungi, or bacteria, along with abiotic modifications such as mechanical processes associated with deposition and possible post­mortem transport, as well as diagenesis (e.g. mineral coatings). bacterial corrosion occurs as pitting and usually has an irregular distribution, while soil corrosion affects a wider area of the bone, usually at one end, and creates a rough surface. digestive corrosion, on the other hand, usually affects the entire bone and produces smooth edges. predation marks include carnivore tooth marks, scratching (represented by a series of three or four parallel shallow striations), corrosion caused by digestion, cut marks, and possibly burned bones. weathering includes cracking, splitting, flaking, erosion, abrasion, and chemical etching. mechanical weathering typically occurs while the bone is still on the surface, whereas chemical etching occurs when the bone is buried. recent modifications caused by excavations or laboratory processing are included in the category of mechanical weathering. the relative abundance (ra) for each element of the skeleton was calculated using the formula by dodson & wexler (1979): %ra = (mne / (mni * e)) * 100, where mne represents the minimum number of skeletal elements, mni is the minimum number of individuals, and e is the number of specific elements present in one skeleton. mni was calculated based on the most abundant skeletal element, based on a body side and age. in addition to the relative abundance, the proportion of skeletal elements was calculated after nannini et al. (2022), using anatomical indices based on andrews (1990), lloveras et al. (2008, 2016), and the normalized ratios modified by pelletier et al. (2020). the following skeletal elements were grouped together to calculate the ratios mentioned above: postcranial elements (pctr), cranial elements (cr), limb elements (pcrap), postcranial long bones (pcrlb), autopodia (aut), zygopodia (z), stylopodia (e), anterior limb (an) and posterior limb (po). 3. results the analyzed samples include most of the skeletal elements present in the marmot skeleton, with a total nisp of 411 (number of identified specimens; table 1). bones (including mandibles with tooth rows) make up 86.6% (nisp = 356) of the samples from the east cave, while the isolated teeth account for 13.4% (nisp = 55). the bone samples exhibit varying degrees of preservation. the majority (nisp =256, 71.9%) of the bones (excluding teeth) from the east cave are well­preserved (with more than 75% of the bone's original structure intact), and almost half of these well­preserved bones are completely intact (nisp = 126, 49.2%). poorly preserved bones account for 28.1% (nisp = 155) of the bone sample from the east cave. based on the determined relative ages of the four most represented skeletal elements in the assemblage, and the side of the body to which the bone belongs, the minimum number of individuals (mni) was calculated (table 1). the highest mni is based on the ulna and includes a minimum of 17 individuals: 2 adults, 6 juvenile and 9 very juvenile. 3.1. anatomical representation the anatomical composition of the identified remains (table 2) shows that the most frequent elements are isolated teeth (13.4% nisp), pelvis (8.8% nisp), tibia (7.5% nisp), and mandible (7.3% nisp), while smaller elements including the atlas, axis and sternum show the lowest values. this can probably be explained by the excavation process, particularly overlooking the smaller bones during the primary excavation. the relative abundance shows a mean value of 28.4% (table 2, fig. 3) which is characterized as low, and is indicative that the sample was affected by the significant loss of some skeletal elements. based on the relative abundance, the ulna is the most represented bone in the assemblage (85.3%), followed by mandible (79.4%), pelvis (76.5%), tibia (73.5%) and femur (64.7%). the lowest relative abundance is calculated for caudal vertebrae (2.2%) and the fibula (2.9%), respectively. ratios between skeletal elements shown in table 3 are indicative of a deficiency in the numbers of postcranial remains compared to the cranial ones with pcrt/cr of 28.5% and pcrap/cr of 30.3%. only when cranial remains are compared with long bones does the pcrlg/cr index show a relatively balanced proportion of 72.4%. while comparison of the lower to upper limb elements shows the dominance of upper limbs (aut/ze = 4.8%), the z/e index of 40% shows a decrease in the abundance of stylopodia over zygopodia. similar numbers are derived in comparison between the posterior and anterior limb elements, showing a loss of the latter (an/po = 38.2%). figure 3. chart showing the relative abundance (ra) of the alpine marmot skeletal elements in the east brina cave. table 3. ratios between the different parts of the marmot skeleton from the east brina cave. index % pctr/cr 28.5 pcrap/cr 30.3 pcrlb/cr 72.4 aut/ze 4.8 z/e 40 an/po 38.2 g eo lo gi a c ro at ic a 120 geologia croatica 78/2 3.2. bone surface modifications 3.2.1. weathering in the analyzed material, mechanical weathering was more dominant (nr = 262; 63.8%) than chemical weathering (nr = 133; 32.4%), while 16 bone remains (3.9%) were not affected by weathering (table 4). among mechanical weathering, erosion was the most dominant type (45.5%), followed by fine line fractures and/or spalling (17.3%), while trampling (2.9%) and abrasion (1%) were rare. damage caused by recent manipulation (i.e. excavation) is recorded at 19 bones (4.6%). pitting, caused by bacterial corrosion, was by far the most prevalent type of chemical weathering (nr = 110; 26.7%), followed by root etching (nr = 21; 5.2%), while soil corrosion was identified on four bones (1.0%). it was very common for a single bone to exhibit multiple weathering marks, including multiple types of mechanical weathering, multiple types of chemical weathering, or a combination of both. 3.2.2. animal and predation marks a total of 98 remains (23.8%) displayed animal­origin surface modifications (fig. 4, pl. 1), with gnawing marks from small carnivores being predominant (nr = 58; 14.1%) compared to only 18 remains (4.3%), that display possible anthropogenic marks (table 5, fig. 5). samples with only animal­origin marks predominate, while a combination of animal and anthropogenic marks was recorded on eight specimens. the identified animal­origin marks include rodent gnawing (3.4%), gnawing of unknown origin (6.8%), small animal scratchin (6.31%), small carnivore bite marks (10.0%), a combination of rodent gnawing and small carnivore bite marks (4.1%), and bite marks of unknown origin (6.8%). anthropogenic­origin marks include cut marks (1.2%; fig. 5), possible cut marks (1.2%), and possible burning (1.9%). 4. discussion 4.1. preservation and representation of skeletal elements the long limb bones are very well preserved making up 30.9% (nisp = 127, table 2) of the nisp. besides being the largest bones, they are also among the most dense bones in the skeleton (lyman et al., 1992) which likely accounts for their high preservation potential and representation in the sediment. the same criterion can be applied to the lower jaws that are also relatively well represented in the sample (7.3% nisp); however, the same cannot be applied to pelvic bones (8.8% nisp) that are among the least dense marmot bones. therefore, it can be assumed that their relative frequency is related to their size and collection bias. the samples studied also contain a significant number of isolated teeth (13.4%), but since teeth are the most resistant part of the skeleton due to their composition, their abundance can be expected. however, 69% (nisp = 38) of nisp isolated teeth are incisors, which are the largest marmot teeth and were therefore the easiest to notice and hand­ pick during the excavation. when considering values of different anatomical indices (table 3), it can be inferred that there is a balanced proportion table 4. bone modification – weathering on alpine marmot skeletal remains from the east brina cave. abbreviations: nr – number of remains, ffs – fine line fractures and spalling, che – chemical etching, re – roots etching and bacterial pitting, ab – abraded, water-worn, er – eroded, tr – trampling, mi – mineral and caco3 coating, bs – black staining. skeletal element nisp ffs nr ffs % che nr che % re nr re % ab nr ab % er nr er % tr nr tr % mi nr mi % bs nr bs % cranium 12 0 0.0 0 0.0 2 0.0 0 0.0 3 25.0 0 0.0 7 58.3 9 75.0 mandibula 30 6 20.0 0 0.0 12 13.3 0 0.0 13 43.3 0 0.0 12 40.0 21 70.0 lower i1 11 9 81.8 0 0.0 4 0.0 0 0.0 3 27.3 2 18.2 5 45.5 9 81.8 upper i1 27 8 29.6 0 0.0 12 0.0 0 0.0 3 11.1 2 7.4 14 51.9 24 88.9 p3 4 to m3 17 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 vertebrae 62 4 6.5 0 0.0 18 3.2 0 0.0 36 58.1 1 1.6 42 67.7 27 43.5 sacrum 2 0 0.0 0 0.0 2 0.0 0 0.0 2 100.0 0 0.0 0 0.0 2 100.0 sternum 1 0 0.0 0 0.0 1 100.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 rib 23 0 0.0 0 0.0 5 115.0 1 4.3 4 17.4 0 0.0 1 4.3 18 78.3 clavicula 8 1 12.5 0 0.0 2 0.0 0 0.0 2 25.0 1 12.5 5 62.5 8 100.0 scapula 11 2 18.2 0 0.0 3 33.0 1 9.1 4 36.4 0 0.0 2 18.2 8 72.7 humerus 23 4 17.4 1 4.3 10 13.0 0 0.0 13 56.5 2 8.7 10 43.5 14 60.9 radius 13 3 23.1 0 0.0 1 0.0 0 0.0 6 46.2 0 0.0 6 46.2 10 76.9 ulna 29 11 37.9 0 0.0 4 0.0 0 0.0 11 37.9 0 0.0 19 65.5 24 82.8 metacarpus 13 0 0.0 0 0.0 9 69.2 1 7.7 5 38.5 0 0.0 5 38.5 10 76.9 pelvis 36 6 16.7 0 0.0 13 5.6 0 0.0 19 52.8 1 2.8 19 52.8 30 83.3 femur 29 11 37.9 2 6.9 10 0.0 0 0.0 17 58.6 2 6.9 10 34.5 19 65.5 tibia 31 5 16.1 0 0.0 4 0.0 0 0.0 26 83.9 0 0.0 6 19.4 20 64.5 fibula 2 0 0.0 0 0.0 1 0.0 0 0.0 0 0.0 0 0.0 0 0.0 2 100.0 calcaneus 3 0 0.0 0 0.0 2 33.3 0 0.0 3 100.0 0 0.0 0 0.0 1 33.3 astragalus 2 0 0.0 0 0.0 0 0.0 0 0.0 2 100.0 0 0.0 0 0.0 0 0.0 metatarsus 13 1 7.7 0 0.0 6 15.4 0 0.0 9 69.2 0 0.0 3 23.1 13 100.0 phalanx 13 0 0.0 1 7.7 10 76.9 1 7.7 6 46.2 1 7.7 4 30.8 13 100.0 total 411 71 17.3 4 1.0 131 31.9 4 1.0 187 45.5 12 2.9 170 41.4 282 68.6 g eologia c roatica 121oros sršen et al.: taphonomy of the alpine marmot (marmota marmota) remains from the late pleistocene deposits of the east brina cave, croatia very low anatomical index of aut/ze%, representing the ratio between the autopodial and long bones, of only 4.8% suggests the absence of paws, corresponding to the results of the analysis by nannini et al. (2022), aut/ze% = 6.5%. however, the pcrlb/cr% ratio, in which paws are excluded, between the front (an/po% = 38.2%) and hind limbs (z/e% = 40%). slightly less balanced proportions can be noted in the ratios between the cranial (pctr/cr% = 28.5%) and postcranial regions (pcrap/cr% = 30.3%), suggesting a decrease in autopodial elements as well as the vertebrae. a figure 4. specimen pbi 21 – left mandible of alpine marmot, lateral and medial views, showing small carnivore (fox) tooth marks, and delicate tooth marks (blue and white squares) of an unknown small animal, possibly from a fox cub. table 5. bone modification – animal and predation marks on the alpine marmot skeletal remains from the east brina cave. abbreviations: nr – number of remains, cm – cut marks, cm? – possible cut marks, pb – possible burning, rg – rodent gnawing, scg – small carnivore gnawing, rcg – rodent and small carnivore gnawing, ug – gnawing of the unknown origin, ssa – scratching from the small animals. skeletal element nisp cm nr cm % cm? nr cm? % pb nr pb % rg nr rg % scg nr scg % rcg nr rcg % ug nr ug nr% ssa nr ssa % cranium 12 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 1 8.3 0 0.0 mandibula 30 0 0.0 0 0.0 1 3.3 0 0.0 12 40.0 2 6.7 5 16.7 8 26.7 lower i1 11 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 1 9.1 1 9.1 upper i1 27 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 1 3.7 0 0.0 p3 4 to m3 17 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 vertebrae 62 0 0.0 1 1.6 0 0.0 0 0.0 0 0.0 0 0.0 1 1.6 0 0.0 sacrum 2 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 sternum 1 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 rib 23 0 0.0 0 0.0 1 4.3 1 4.3 0 0.0 0 0.0 0 0.0 0 0.0 clavicula 8 0 0.0 0 0.0 0 0.0 0 0.0 2 25.0 0 0.0 0 0.0 0 0.0 scapula 11 0 0.0 0 0.0 0 0.0 0 0.0 4 36.4 0 0.0 2 18.2 1 9.1 humerus 23 0 0.0 0 0.0 0 0.0 1 4.3 5 21.7 2 8.7 0 0.0 1 4.3 radius 13 1 7.7 0 0.0 1 7.7 0 0.0 7 53.8 1 7.7 2 15.4 0 0.0 ulna 29 2 6.9 2 6.9 1 3.4 5 17.2 3 10.3 4 13.8 1 3.4 3 10.3 metacarpus 13 0 0.0 0 0.0 0 0.0 0 0.0 1 7.7 0 0.0 1 7.7 0 0.0 pelvis 36 0 0.0 0 0.0 2 5.6 1 2.8 4 11.1 1 2.8 6 16.7 0 0.0 femur 29 1 3.4 1 3.4 2 6.9 4 13.8 1 3.4 4 13.8 4 13.8 5 17.2 tibia 31 1 3.2 1 3.2 0 0.0 2 6.5 2 6.5 3 9.7 2 6.5 7 22.6 fibula 2 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 calcaneus 3 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 astragalus 2 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 metatarsus 13 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 phalanx 13 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 1 7.7 0 0.0 total 411 5 1.2 5 1.2 8 1.9 14 3.4 41 10.0 17 4.1 28 6.8 26 6.3 g eo lo gi a c ro at ic a 122 geologia croatica 78/2 is on the other hand, showing the highest value of 72.4%. considering all the ratios, it can be concluded that the high proportion of almost complete skeletons is indicative of complete marmots whether they lived and died in situ or were transported into the east cave by predators. another correlation with the study of nannini et al. (2022) can be made in the low percentages of vertebrae and ribs. however, in the current study, the main reason for this is suggested to be the sampling method, since samples were collected in the 1960’s, when the focus was on larger fauna. additionally, the absence of paw and tail elements (fig. 3) might also be related to the same reason, caused by inadequate sampling. as noted before, the indices of relative abundances could be correlated with nannini et al. (2022), as well as therein mentioned references, all focusing on the late glacial anthropogenic accumulations, but also reporting the presence of complete skeletal remains. it should be noted that the majority of bones from the east cave are well preserved with only minimal signs of weathering, which can be due to the alkaline environment of the carbonate bedrock but also a taphonomic (collection) bias. it is also evident that a large part of the sample consists of juvenile (and very juvenile) marmot bones, which show no signs of predation and/or only minimal weathering. since marmot burrows were found in the east cave (fig. 2c; malez, 1963a), this could indicate that these juvenile individuals died from natural causes, most likely during their first hibernation when they are in their most vulnerable life stage because of lower body weight and body fat percentage (mann et al., 1993). considering that adult individuals leave the natal colony upon reaching sexual maturity (kryštufek, 1991), it can be concluded that, over the years, multiple generations of alpine marmot colonies chose the brina caves as their habitat. 4.2. animal traces the gnawing and bite marks from small carnivores such as martens and foxes are the most dominant taphonomic traces of animal origin (14.1%) within the studied samples (fig. 6). since excellent impressions of nearly complete predator bites have been preserved on certain specimens (pbi 21, pbi 100; fig. 4, pl. 1), a comparison with jaws from the recent comparative collection allowed for the precise identification of the predators as martens and foxes (pl. 1). although their bones were not found in the brina caves, according to malez (1979) both species lived in the area during the upper pleistocene. predator bite marks were also found on the lower jaws of juvenile individuals, whose permanent teeth had just begun to emerge, indicating that marmot pups, only a few months old, served as easy prey for predators. in the sciuridae family (squirrels), permanent teeth typically emerge at around 3–4 months of age (cardini & thorington, 2006), which would mean that predators hunted marmot pups in late summer or early autumn. during this period, as they prepare for hibernation, adult marmots have their highest body weight and fat content, making it logical that they, too, were more frequently preyed upon during this time. 4.3. anthropogenic traces one of the premises of this study was an attempt to find evidence of human hunting of marmots, considering that the upper pleistocene hunters from the area, and similar sites in montenegro, such as vrbička and crvena stijena, have been documented (borić et al., 2014; mihailović, 2017). large hunting camps specialized in hunting alpine marmots have also been documented in northern italy (nannini et al., 2022; romandini et al., 2012, 2018). although a complete taphonomic analysis of alpine marmot bones in croatia is still figure 5. specimen pbi 278 – thoracic vertebra showing fine line fractures, erosion, black staining and cut marks (white square). g eologia c roatica 123oros sršen et al.: taphonomy of the alpine marmot (marmota marmota) remains from the late pleistocene deposits of the east brina cave, croatia missing, miracle (2007) mentions a single alpine marmot bone with a cut mark in his monograph on the hušnjakovo neandertal site near krapina. in the samples studied, five bones have been definitively identified as bearing cut marks, with an additional five potentially exhibiting similar marks (table 5). however, a challenge in identifying these marks arises from the preservation of the brina cave bones in a light colour, as any potential cut marks also appear in a similar light, white shade. such cut marks were previously considered to be a product of recent manipulation by excavators or curation and were not considered in taphonomic analysis. nonetheless, recent forensic research (marin­monfort et al., 2018) has proven that there is no difference in colour between recent and fossil traces on bones. therefore, some of the incisions, which would otherwise be considered recent, were identified as fossil markings (fig. 5). for the five samples with potential cut marks, it could not be determined with certainty whether their characteristics can be classified as incisions, and further detailed research is necessary. when considering the number of specimens with (potential) anthropogenic manipulation, only 2.4% of the bones in the sample bear cut marks. this is four times fewer than at the grotte di pradis site, where a specialized camp for hunting alpine marmots was found in northern italy (nannini et al., 2022). burning on eight remains was labeled as potential, as the only criterion by which burning could be determined was the colour of the bones (marques et al., 2018). however, the bones could have also acquired such a colour from the sediment in which they were found since the sediment from layer c, where the majority of the marmot bones were found, was brownish clay (malez, 1963b, 1975), and therefore burning could not be confirmed with certainty. if all samples with potential burning were considered to have been charred, they would make up 1.9% of the bone samples, which is about three times fewer than in grotte di pradis (nannini et al., 2022). after the loss of plains during the late glacial interstadial warming, humans seasonally exploited high­altitude ecosystems (nannini et al., 2022, and references therein). in the italian pre­alps, humans exploited and consumed marmots in large numbers; moreover, some sites were specialized camps for marmot exploitation. when comparing the marmot assemblage from grotta di pradis (nannini et al., 2022) to that of east brina cave, excellent bone preservation can be noted at both sites, with no evidence of digested bone and a nearly identical representation of anatomical elements. however, there are striking differences in animal and anthropogenic traces: while anthropogenic modifications, such as cut marks, dominate at pradis and animal traces are rare, small carnivore gnawing marks are prevalent at east brina. in both caves, tooth marks correspond to fox and marten tooth­rows. additionally, in pradis, adult remains are more prevalent, whereas in brina, juvenile remains dominate. this difference also suggests distinct accumulation agents: humans in pradis and carnivores in brina. 5. conclusions the discovery of numerous skeletal remains of alpine marmots in the east brina cave near drniš provides significant insights into the palaeoecology and taphonomic processes of this species during the late pleistocene. a total of 356 bone remains (including mandibles with teeth) and 55 isolated teeth, making up a total of 411 skeletal fragments, were found in the east cave, representing the highest occurrence of alpine marmot skeletal remains in dalmatia. these finds suggest that the caves were used either as active burrowing sites or as accumulation areas resulting from predation and natural mortality. taphonomic analysis reveals that the preservation and representation of skeletal elements were influenced by a combination of factors, including bone density, collection bias, and environmental conditions. while natural death was the primary cause of bone accumulation, secondary agents such as small carnivores, particularly martens and foxes, played a significant role in modifying the sample. predation patterns indicate that marmots, especially juvenile individuals, were targeted by predators, primarily during the autumn when they are at their maximum weight, shortly before entering hibernation. the presence of cut­marked bones provides important, albeit limited, evidence of occasional human interaction with figure 6. specimen pbi 114 – right humerus, cranial and caudal view, with small carnivore gnaw marks (blue squares). g eo lo gi a c ro at ic a 124 geologia croatica 78/2 marmots in the region. while the frequency of anthropogenic modifications is lower than at specialized hunting sites in northern italy, the fossil remains contribute to the broader understanding of palaeolithic subsistence strategies in southeastern europe. although the extent of human exploitation remains uncertain, the combination of natural accumulation, carnivore activity, and occasional human intervention suggests a complex interplay of ecological and cultural factors shaping the entire sample of the brina caves. further research, including detailed microscopic and geochemical analyses such as environmental sem analyses of cut marks and eds analyses of mineral staining and coatings, may help clarify the role of humans in the accumulation of these remains and refine taphonomic interpretations. by integrating these finds with regional studies, the brina caves offer valuable data for reconstructing the pleistocene eco­ systems and understanding the dynamic interactions between humans, animals, and their environments in southeastern europe. references andrews, p. (1990): owls, caves and fossils: predation, preservation and accumulation of small mammal bones in caves, with an analysis of the pleistocene cave faunas from westbury­sub­mendip, somerset, uk.– university of chicago press, 239 p. armitage, k.b. (2013): climate change and the conservation of marmots.– natural science, 5, 36–43. https://doi.org/10.4236/ns.2013.51006 behrensmeyer, a.k. (1978): taphonomic and ecologic information from bone weathering.– paleobiology, 4/2, 150–162. http://doi.org/10.1017/ s0094837300005820 behrensmeyer, a.k., stayton, c.t. & chapman, r.e. (2003): taphonomy and ecology of modern avifaunal remains from amboseli park, kenya.– paleobiology, 29/1, 52–70. http://doi.org/10.1666/0094­8373 (2003)029%3c0052:taeoma%3e2.0.co;2 borić, d., cristiani, e., vušović­lučić, z., borovinić, n. & mihailović, d. (2014): lgm marmot hunting at vrbička cave in the dinaric alps.– in: where the wild things are, durham, 8–10 jan 2014, durham university, poster. cardini, a. & thorington, r.w. (2006): postnatal ontogeny of marmot (rodentia, sciuridae) crania: allometric trajectories and species divergence.– journal of mammalogy, 87/2, 201–215. https://doi.org/10.1644/05­mamm­a­242r1.1 clot, a. (1975): ii. les dépôts ossifères de montoussé (hautes­pyrénées).– quaternaire, 12, 205–206. https://doi.org/10.3406/quate.1975.1269 dodson, p. & wexlar, d. (1979): taphonomic investigations of owl pellets.– paleobiology, 5/3, 275–284. https://doi.org/10.1017/s0094837300006564 erbajeva, m.a. & alexeeva, n.v. (2009): pliocene­recent holarctic marmots: overview.– ethology ecology & evolution, 21/3–4, 339–348. https://doi.org/10.1080/08927014.2009.9522488 estraviz­lópez, d., cuenca­bescós, g., blain, h.a., lópez­garcía, j.m., núñez­lahuerta, c. & galán, j. (2021): the oldest european marmots: metrical study of the marmota fossils from the early and middle pleistocene of sierra de atapuerca sites (burgos, spain).– comunicações geológicas., 108, 57–61. https://doi.org/10.34637/crz1­da69 fernández­jalvo, y. & andrews, p. (2016): corrosion and digestion.– in: atlas of taphonomic identifications: 1001+ images of fossil and recent mammal bone modification. springer, 1–15. https://doi.org/10.1007/978­ 94­017­7430­7 hodžić, m. & šorić, ž. (2011): neke klimatske posebnosti prostora srednjodalmatinske zagore i njihov odnos prema priobalju [in croatian].– in: matas, m. & faričić, j. (eds): zagora između stočarsko­ratarske tradicije te procesa litoralizacije i globalizacije, zbornik radova, zadar – dugopolje, oct. 19–21, 2010, university of zadar, kulturni sabor zagore, ogranak matice hrvatske, split. indra, l., errickson, d., young, a. & löscher, s. (2022): uncovering forensic taphonomic agents: animal scavenging in the european context.– biology, 11, 601. https://doi.org/10.3390/biology11040601 kryštufek, b. (1991): sesalci slovenije [in croatia].– prirodoslovni muzej slovenije, ljubljana, 294 p. lloveras, l., moreno­garcía, m. & nadal, j. (2008): taphonomic analysis of leporid remains obtained from modern iberian lynx (lynx pardinus) scats.– journal of archaeological science, 35/1, 1–13. https://doi. org/10.1016/j.jas.2007.02.015 lloveras, l., maroto, j., soler, j., thomas, r., moreno­garcía, m., nadal, j. & soler, n. (2016): the role of small prey in human subsistence strategies from early upper palaeolithic sites in iberia: the rabbits from the evolved aurignacian level of arbreda cave.– journal of quaternary science, 31/5, 458–471. https://doi.org/10.1002/jqs.2870 lyman, r.l. (1987): zooarchaeology and taphonomy: a general consideration.– journal of ethnobiology, 7/1, 93–117. lyman, r.l. (2008): quantitative paleozoology.– cambridge university press, 374 p. lyman, r.l., houghton, l.e. & chambers, a.l. (1992): the effect of structural density on marmot skeletal part representation in archaeological sites.– journal of archaeological science, 19, 557–573. malez, m. (1963a): paleonotološka i speleološka istraživanja u 1960. godini [in croatian].– ljetopis jugoslavenske akademije znanosti i umjetnosti, 67, 250–269. malez, m. (1963b): paleontološka i stratigrafska istraživanja nekih kvartarnih lokaliteta u 1961. godini [in croatian].– ljetopis jugoslavenske akademije znanosti i umjetnosti, 68, 253–262. malez, m. (1970): izvještaj o paleontološkim i paleolitskim istraživanjima u 1968. godini [in croatian].– ljetopis jugoslavenske akademije znanosti i umjetnosti, 74, 429–436. malez, m. (1971a): kvartargeološka, paleontološka i speleološka istraživanja u 1969. godini [in croatian].– ljetopis jugoslavenske akademije znanosti i umjetnosti, 75, 399–405. malez, m. (1971b): izvještaj o kvartargeološkim istraživanjima u 1970. godini [in croatian].– ljetopis jugoslavenske akademije znanosti i umjetnosti, 75, 411–413. malez, m. (1972): rasprostranjenost hladnodobnih životinja u gornjem pleistocenu jugoistočne evrope [uber die verbreiteung kaltzeitlicher tiere im jungeren pleistozan sudost­europas – in croatian].– rad jugoslavenske akademije znanosti i umjetnosti, 364, 133–180. malez, m. (1975): neki problemi paleolitika na istočnoj obali jadrana [einige probleme des palӓolithikums an der ostküste des adriatischen meeres – in croatian].– rad jugoslavenske akademije znanosti i umjetnosti, 371, 121–153. malez, m. (1979): paleolitsko i mezolitsko doba.– in: benac, a. (ed.): praistorija jugoslavenskih zemalja, i. [in croatian].– svijetlost i akademija nauka i umjetnosti bosne i hercegovine, sarajevo, 195–295. malez, m. & rabeder, g. (1984): neues fundmaterial von kleinsäugern aus der altpleistozänen spaltenfüllung podumci i in norddalmatien (kroatien, jugoslawien).– beiträge zur paläontologie von österreich, 11, 439–510. malez, v. (1995): fosilni nalazi alpskog svizca (marmota marmota l.) u hrvatskim špiljama [in croatian].– in: vlahović, i., velić, i. & šparica, m. (eds.), zbornik radova 1. hrvatski geološki kongres, institut za geološka istraživanja, hrvatsko geološko društvo, 351–353. mann, c.s., macchi, e. & janeau, g. (1993): alpine marmota (marmota marmota, l.).– journal of mountain ecology, 1, 17–30. marin­monfort, m.d., suñer, m. & fernández­jalvo, y. (2018): characterization of recent marks produced on fossil bone surface during sullegic and trephic processes and their influence on taphonomic studies.– quaternary international, 481, 3–13. https://doi.org/10.1016/j.quaint.2017.07.039 https://doi.org/10.4236/ns.2013.51006 https://doi.org/10.4236/ns.2013.51006 https://www.jstor.org/stable/2400283 http://doi.org/10.1017/s0094837300005820 http://doi.org/10.1017/s0094837300005820 https://doi.org/10.1644/05-mamm-a-242r1.1 https://doi.org/10.1644/05-mamm-a-242r1.1 https://doi.org/10.3406/quate.1975.1269 https://doi.org/10.3406/quate.1975.1269 https://doi.org/10.1017/s0094837300006564 https://doi.org/10.1017/s0094837300006564 https://doi.org/10.1080/08927014.2009.9522488 https://doi.org/10.1080/08927014.2009.9522488 https://doi.org/10.34637/crz1-da69 https://doi.org/10.1007/978-94-017-7430-7 https://doi.org/10.1007/978-94-017-7430-7 https://doi.org/10.1007/978-94-017-7430-7 https://doi.org/10.3390/biology11040601 https://doi.org/10.1016/j.jas.2007.02.015 https://doi.org/10.1016/j.jas.2007.02.015 https://doi.org/10.1002/jqs.2870 https://doi.org/10.1002/jqs.2870 https://doi.org/10.1016/j.quaint.2017.07.039 https://doi.org/10.1016/j.quaint.2017.07.039 https://doi.org/10.1016/j.quaint.2017.07.039 g eologia c roatica 125oros sršen et al.: taphonomy of the alpine marmot (marmota marmota) remains from the late pleistocene deposits of the east brina cave, croatia marques, m.p.m., mamede, a.p. & vassalo, a.r. (2018): heat­induced bone diagenesis probed by vibrational spectroscopy.– scientific reports, 8, 15935. https://doi.org/10.1038/s41598­018­34376­w mauch lenardić, j. & klepač, k. (2009): late pleistocene alpine marmot (marmota marmot) (linnaeus, 1758) from some croatian sites.– in: abstracta & contacts quaver 2009 – meeting of the quaternary vertebrate research group, bradford, apr 16–17, 2009, university of bradford, 19. mauch lenardić, j., oros sršen, a. & radović, s. (2018): quaternary fauna of the eastern adriatic (croatia) with the special review on the late pleistocene sites.– quaternary international, 494, 130–151. https://doi.org/10.1016/j.quaint.2017.11.028 maul, l. (1990): überblick über die unterpleistozänen kleinsäugerfaunen europas.– quartärpaläontologie, 8, 153–191. menéndez, i., zelditch, m.l., tejero­cicuéndez, h., swiderski, d.l., carro­rodríguez, p.m., fernández, m.h., álvarez­sierra, m.á. & cano, a.r.g. (2023): dietary adaptations and tooth morphology in squirrels: insights from extant and extinct species.– palaeogeography palaeoclimatology palaeoecology, 629, 111788. https:// doi.org/10.1016/j.palaeo.2023.111788 mihailović, d. (2017): paleolithic­mesolithic crvena stijena in relation to other sites.– in: wallon, r. (ed.): crvena stijena in cultural and ecological context.– montenegrin academy of sciences and arts; national museum of montenegro, podgorica, 205–229. miracle, p.t. (2007): the krapina paleolithic site: zooarchaeology, taphonomy, and catalog of the faunal remains.– hrvatski prirodoslovni muzej, zagreb, 345 p. nannini, n., duches, r., fontana, a., romandini, m., boschin, f., crezzini, j. & peresani, m. (2022): marmot hunting during the upper palaeolithic: the specialized exploitation at grotte di pradis (italian pre­alps).– quaternary science review, 277, 107364. https://doi. org/10.1016/j.quascirev.2021.107364 paunović, m. & rabeder, g. (2000): paleoecological analysis of the early pleistocene vertebrate fauna from razvodje and tatinja draga (croatia).– beiträge zur paläontologie (wien), 25, 87–94. paunović, m., jambrešić, g., brajković, d., malez, v. & mauch lenardić, j. (2001): last glacial settlement of croatia: catalogue of fossil sites dated to the ois 2&3.– acta geologica, 26/2, 27–70. pelletier, m., desclaux, e., mallye, j.b. & crégut‐bonnoure, e. (2020): identifying the accidental‐natural mortality of leporids in the archaeological record: insights from a taphonomical analysis of a pitfall without evidence of human presence.– journal of quaternary science, 35/5, 677–694. https://doi.org/10.1002/jqs.3210 pilaar birch, s.e. & vander linden, m. (2018): a long hard road… reviewing the evidence for environmental change and population history in the eastern adriatic and western balkans during the late pleistocene and early holocene.– quaternary international, 465, 177–191. https://doi.org/10.1016/j.quaint.2016.12.035 ramousse, r. & le berre, m. (1993): management of alpine marmot populations.– oecologia montana, 2/1­2, 23–29. romandini, m., peresani, m., gurioli, f. & sala, b. (2012): marmota marmota, the most common prey species at grotta del clusantin: insights from an unusual case­study in the italian alps.– quaternary international, 252, 184–194. https://doi.org/10.1016/j.quaint.2011.03.016 romandini, m., thun hohenstein, u., fiore, i., tagliacozzo, a., perez, a., lubrano, v., terlato, g. & peresani, m. (2018): late neandertals and the exploitation of small mammals in northern italy: fortuity, necessity or hunting variability?– quaternaire, 29, 61–67. https://doi.org/10.4000/quaternaire.8626 šanjek, r. (2023): tafonomska analiza ostataka alpskog svisca (marmota marmota) iz gornjopleistocenskih naslaga istočne i zapadne pećine u brini kod drniša [taphonomic analysis of bone remains of alpine marmot (marmota marmota) from the late pleistocene deposits of the brini caves near drniš – in croatian].– unpubl. graduate thesis, faculty of science, university of zagreb, 79 p. tappen, m., adler, d.s., ferring, c.r., gabunia, m., vekua, a. & swisher iii, c.c. (2002): akhalkalaki: the taphonomy of an early pleistocene locality in the republic of georgia.– journal of archaeological science, 29/12, 1367–1391. https://doi.org/10.1006/jasc.2001.0790 tomé, c. (1998): étude de la marmotte des alpes (marmota marmota l.) et de son exploitation par les chasseurs du paléolithique final de la grotte colomb (méaudre­vercors­france).– mémoire de maîtrise, université pierre mendès france de grenoble ii, 200 p. toškan, b. (2007): remains of large mammals from divje babe i: stratigraphy, taxonomy and biometry.– in: turk i. (ed.): divje babe i: upper pleistocene palaeolithic site in slovenia. part i: geology and palaeontology, opera inst. arch. slov. 13, 221–278. tukša, i. (2019): metrijska analiza skeletnih ostataka planinskih svizaca (marmota marmota (linnaeus, 1758)) iz gornjopleistocenskih naslaga pećina u brini kod drniša. [metrical analyses of the alpine marmot (marmota marmota (linnaeus, 1758)) skeletal remains from the late pleistocene deposits of the pećine u brini caves near drniš – in croatian].– unpubl. graduate thesis, faculty of science, university of zagreb, 63 p. zimina, r.p. & gerasimov, i.p. (1973): the periglacial expansion of marmots (marmota) in middle europe during late pleistocene.– journal of mammalogy, 54, 2, 327–340. web sources: now database (2023): new and old worlds – database of fossil mammals. available at: https://nowdatabase.luomus.fi/species.php?p=locality. accessed on: march 11th 2025. paleobiology database (2025): marmota marmota (alpine marmot). available at: https://paleobiodb.org/classic/checktaxoninfo?taxon_no=47899&is_ real_user=1. accessed on: march 11th 2025). https://doi.org/10.1038/s41598-018-34376-w https://doi.org/10.1038/s41598-018-34376-w https://doi.org/10.1016/j.quaint.2017.11.028 https://doi.org/10.1016/j.quaint.2017.11.028 https://doi.org/10.1016/j.palaeo.2023.111788 https://doi.org/10.1016/j.palaeo.2023.111788 https://doi.org/10.1016/j.palaeo.2023.111788 https://doi.org/10.1016/j.quascirev.2021.107364 https://doi.org/10.1016/j.quascirev.2021.107364 https://doi.org/10.1002/jqs.3210 https://doi.org/10.1002/jqs.3210 https://doi.org/10.1016/j.quaint.2016.12.035 https://doi.org/10.1016/j.quaint.2016.12.035 https://doi.org/10.1016/j.quaint.2011.03.016 https://doi.org/10.1016/j.quaint.2011.03.016 https://doi.org/10.4000/quaternaire.8626 https://doi.org/10.4000/quaternaire.8626 https://doi.org/10.1006/jasc.2001.0790 https://nowdatabase.luomus.fi/species.php?p=locality https://paleobiodb.org/classic/checktaxoninfo?taxon_no=47899&is_real_user=1 https://paleobiodb.org/classic/checktaxoninfo?taxon_no=47899&is_real_user=1 g eo lo gi a c ro at ic a 126 geologia croatica 78/2 plate 1. a) pbi 15 – left mandible, lateral and medial views showing fine line fractures, spalling, rodent tooth marks (red square), mineral coating and black staining; b) pbi 221 – left tibia, caudal view, with four cut marks (green square); c) pbi 100 – left scapula of an alpine marmot with crenulated edge of the scapula blade and two (puncture) tooth marks that correspond to the lower canines of marten from the recent reference collection; d) pbi 21 – left mandible of an alpine marmot with tooth marks that correspond to the upper incisors of fox from the recent reference collection. g eologia c roatica 127oros sršen et al.: taphonomy of the alpine marmot (marmota marmota) remains from the late pleistocene deposits of the east brina cave, croatia plate 2. a) pbi 32 and pbi 37 – right mandible, medial and lateral views showing bacterial corrosion (blue square) and light-colored mineral coating; b) pbi 193 – right femur, caudal view showing bacterial corrosion (pitting, green square); c) pbi 200 – right juvenile femur, caudal view showing small animal scratching (red square); d) pbi 198 – right femur, cranial view showing small animal scratching (violet square); e) pbi 116 – right humerus, cranial and caudal views showing soil corrosion (yellow squares). www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2024 | 77/3 | 193–233 | 18 figs. | 1 tab. | 1. introduction 1.1. microorganisms and mineral substrates microorganisms are among the first occupants of mineral sur­ faces in aquatic environments, forming biofilms (krumbein et al., 2003) and microbial mats (gerdes et al., 1993). these coatings experience changed physico­chemical conditions upon contact with the substrate (kühl & revsbech, 2001) which include changes in carbonate saturation levels in the surrounding solution that may induce calcification (kühl et al., 2003; krause et al., 2019). carbonate dissolution can also occur (garcia­pichel et al., 2010; grange et al., 2015; guida & garcia­pichel, 2016; masse et al., 2020). microorganisms that settle on mineral surfaces as epiliths often exude organic acids and chelating agents able to dissolve mineral matter of the rock or shell surface and leave etch mark traces. microbial settlers use a variety of strategies to enter a rock’s interior and become endolithic. the conceptual understanding of microbial activities affecting rocks goes back to their first discoverers, the biologists bornet (1891) and bornet & flahault (1888, 1889). abbé pierre frémy, who published a comprehensive study on african and mediterranean cyanobacteria (frémy, 1930, 1934), expressed the distinction between etching and penetration for the phototrophs as “les algues cariant et perforant” (frémy, 1945). we follow the same distinction in describing microbial traces in the aphotic deep sea, by distinguishing between ichnotaxonomy of microboring traces in marine aphotic depths stjepko golubic1, gudrun radtke2, james e. hook3 and susan e. campbell4,* 1 boston university, department of biology, 5 cummington mall, boston ma, 02215, usa; (stjepko.golubicbu@gmail.com) 2 umwelt und geologie, hessisches landesamt für naturschutz, rheingaustraße 186, d-65203 wiesbaden, germany; (gudrun.radtke@hlnug.hessen.de) 3 cambridge, ma 02139, usa; (hookshyu@aol.com) 4 quincy, ma 02169, usa; (*corresponding author: bostoncampbell@gmail.com) doi: 10.4154/gc.2024.19 abstract microboring traces in carbonate skeletal fragments deposited in aphotic depths of the oceans are studied, evaluated, and described with respect to their marine ecology and palaeoecology as well as ichnotaxonomy. sand-size deep sea sediment particles dredged from depths ranging between 600 and 3266 m of the bermuda pedestal, central atlantic ocean, the florida escarpment, the mediterranean sea, the red sea and the indian ocean were studied. following ichnological rules, trace fossils are described as ichnogenera and ichnospecies, defined as products of organismal behaviour. this, in our view, refers to the growth habit of microboring organisms in response to environmental stimuli within the substrate they penetrate. the problem of palaeobathymetry is discussed in conjunction with the distinction between light-dependent and light independent microboring organisms, with the emphasis on the latter. we considered this distinction to be important because only the light-dependent microborers have been recognized as indicators of ancient depositional depths, whereas the light-independent ones are expected to occur at any depth, subject to the availability of organic nutrients. microboring organisms often leave morphologically similar traces due to convergent evolution. their responses may change during their life cycle; they may produce different traces when pursuing their vegetative vs. reproductive functions. new ichnotaxa are described. all are regarded as organotrophs given their aphotic zone deep sea origin. this work presents the most complete set of deep sea microbial euendolith traces, to date. traces of microboring organisms left in the interior of carbonate substrates from those expressed as etch marks on the surface of carbonate substrates. the presence of microorganisms in rocks and other mineral­supported hard substrates was noticed by researchers working in the photic zone who observed green, and some­ times, red or black lines about a millimeter beneath the surface of limestone rocks (ercegović, 1925; le campion­ alsumard, 1969; radtke & golubic, 2011), ooid grains (al­thukair & golubic, 1991a, b; al­thukair et al., 1994), mollusc shells (boekschoten, 1966; radtke, 1993; radtke & golubic, 2005; radtke et al., 2011), coral skeletons (chazottes et al., 1995; le campion­alsumard et al., 1995a, b; kolodziej et al., 2012; pica et al., 2016) as well as in stromatolites (reid et al., 2011). although endolithic microorganisms have been observed for many years, the distinction between epiliths and distinct types of endoliths was defined later by consensus (golubic et al., 1981). some microorganisms enter the rock by lining cracks and fissures of a substrate (e.g., diels, 1914) as chasmo­endoliths, or by colonizing preexisting cavities inside porous rocks (friedmann, 1971) as crypto­endoliths, while microboring organisms that actively penetrate limestone rocks (bachmann, 1915), dolomites, and carbonatic and phosphatic skeletons are defined as euendoliths though the term “endolith” is often used interchangably. microboring or euendolithic organisms penetrate carbonate substrates and article history: manuscript received: june 13, 2024 revised manuscript accepted: september 24, 2024 available online: october 28, 2024 keywords: bioerosion, deep sea, ichnotaxo nomy, microbial euendoliths, organotrophy, palaeobathymetry g eo lo gi a c ro at ic a 194 geologia croatica 77/3 reside in the boreholes they have produced. microbial euendoliths can be prokaryotic, eukaryotic, and potentially also archaea. they leave traces that conform closely to the morphological outlines of their makers (campbell & hoffman, 1979). a combination of microbial euendoliths and subsequent calcification in the formation of micritic envelopes around sediment particles was studied by bathurst (1966), who emphasized the importance of comparing ancient and modern environmental settings to ascertain the geological significance of such activities. this phenomenon was thought to be restricted to shallow subtidal ranges but was later found in the deep sea as well (hook et al., 1984). most studies of organismal impact on sediments (bioerosion) have been carried out in marine coastal regions (tribollet, 2008a; tribollet, 2008b), where it was shown that the presence of microborers conducting biocorrosion activity (tribollet et al., 2011a) attracts grazing and scraping animals, such as molluscs, echinoderms, and parrot fish. grazers remove the endoliths mechanically (bioabrasion), together with parts of the surrounding mineral substrate (schneider, 1976; schneider & torunski, 1983). together with chemical removal or biocorrosion by microorganisms, these activities described here amount to bioerosion (tribollet et al., 2011b; wisshak et al., 2011). biocorrosion and bioerosion are widely distributed activities on coral reefs (chazottes et al., 1995; tribollet & golubic, 2005; clements et al., 2016). both also take place in freshwater (schneider & le campion­ alsumard, 1999), terrestrial (ercegović, 1925; golubic & schneider, 2003; golubic et al., 2015), and in extreme desert environments (wierzchos et al., 2018). the ecologically important activities described here and by those authors differ from those in applied research that centre on the biocorrosion of metals (beech & gaylarde, 1999; hamilton, 2003). microbial biocorrosion and bioerosion are gradual but persistent activities affecting and shaping earth’s mineral surfaces. geologists view bioerosion as an important landscape­modifying force in modern and ancient environments (radtke et al. 1997; vogel et al., 2000). neumann (1966) and rioult & dangeard (1967) studied how they contribute to the development of coastal notches. the relationships between microborings and their grazers changes along vertical profiles of coastal notches (radtke et al., 1996), as it does across coral reef ecosystems (chazottes et al., 2009; tribollet et al., 2019). traces attracted the attention of geologists and palaeontologists because they are better preserved generally in the fossil record than the organisms that produce them. if correlated with environmental conditions under which they formed, traces can serve as palaeoenvironmental indicators. such information needs to be obtained from the study of modern environments (seilacher, 1967). both phototrophic and organotrophic euendoliths leave traces that readily preserve and are common in the fossil record (wisshak et al., 2019). euendoliths and their microboring traces have a long geologic history and an abundant fossil record, extending from the lower proterozoic to the recent. a microboring cyanobacterium eohyella campbellii zhang & golubic, 1987, penetrated lithified stromatolite layers in the early proterozoic dahongyu formation, hebei province, north china about 1.7 billion years ago (zhang & golubic, 1987, pl. 1). microbial euendoliths bored into ooids in precambrian time 570 to 700 million years ago (campbell, 1982a). endolithic cyanobacteria seem to have been well established and diversified by the end of the proterozoic (knoll et al., 1986; green et al., 1988). the shapes of microorganisms and their boring traces have changed remarkably little over enormous spans of geological time (campbell, 1982a, b; knoll & golubic, 1992; schopf & klein, 1992; golubic & knoll, 1993). fossils of non­endolithic multicellular red algae have been dated to 1.6 billion years ago (krumbein, 2010; bengtson et al. 2017), and fossils of multicellular fungi date to about one billion years ago (loron et al., 2019a, b). the early origin of eukaryotes is discussed in many contributions published in recent years (butterfield, 2015; javaux & knoll, 2016; adam et al., 2017; sanchez­baracaldo et al., 2017), but no eukaryotic fossil microborings have yet been described from that early age. the earliest microbial endoliths of the phanerozoic were reported from the lower cambrian (zhang & pratt, 2008). fossils of the euendolithic phase of a bangialean red alga palaeoconchocelis starmachii, and its microboring traces were described from the ca. 425­million­year­old upper silurian of poland (campbell et al., 1979; campbell, 1980) with the trace later named conchocelichnus (radtke et al. 2016) when found without an associated body fossil. the ichnoname is conchocelichnus seilacheri (radtke et al. 2016) in honour of seilacher. campbell et al. (1979) recognized the endolithic conchocelis stages of bangiacean rhodophytes in the fossil record and budd & perkins (1980) reported their modern distribution to 70 m depth. descriptions of fossil microboring traces are increasingly plentiful in the ordovician (vogel & brett, 2009) and later. they have been described from different periods throughout the phanerozoic (kazmierczak & golubic, 1976; vogel et al., 1987; schmidt, 1990; radtke, 1991; brett et al., 1993; glaub, 1994; hofmann, 1996; bundschuh, 2000; glaub et al., 2007). due to their microscopic dimensions and inaccessible habitat within solid rocky substrates, microboring organisms and their traces could not be studied in any detail until modern technology to create plastic casts of them that enable study by scanning electron microscopy was developed (see golubic et al., 1983, 2016, 2019; vogel & brett, 2009). our views on how to study and interpret fossil microbial euendoliths have developed over time. a key viewpoint that distinguishes our work from others is that traces of microbial endoliths lend themselves to population level studies. this allows multiple morphological features to be discerned as well as how they vary within an ichnotaxon within such populations. after four decades of observing vast numbers of bored substrates and studying many living taxa in great detail, we are confident our work has encompassed the great majority of both modern and g eologia c roatica 195golubic et al.: ichnotaxonomy of microboring traces in marine aphotic depths pleistocene examples of these deep sea ichnotaxa as well as many much older microbial euendolithic traces. this provides us with a perspective that is both broader and more specialized than at the outset of our work and also far more comprehensive than older contributions by colleagues who have contributed taxonomic descriptions of a single taxon from one or only a few localities. similarly, our earlier and current work has clarified many ichnotaxa previously described. 1.2. phototrophic vs. organotrophic microborers oxygenic photosynthesis that evolved in cyanobacteria, followed by endosymbiosis and then further differentiation into plastids, provided energy generation to various groups of algae and plants (falkowski et al., 2004), including microbial euendoliths. boring of carbonate substrates by microbes is known among light­dependent cyanobacteria (ercegović, 1925, 1932; couradeau et al.,2017; palinska et al., 2017), the eukaryotic red (batters, 1892; tseng & chang, 1955; miura, 1961; campbell & cole, 1984) and green algae (lukas, 1974, 1978; massé et al., 2020). light­independent microorganisms such as fungi (kohlmeyer, 1969; höhnk, 1969; golubic et al., 2005; golubic et al.,2007), protists (wisshak & rüggeberg, 2006), and suspected (i.e., inferred, not yet proved) organotrophic prokaryotes, also developed the euendolithic habit. the word “micro­organism” means small living thing and includes animals, like micro sponges. accordingly, we have included all micro­sized euendolithic traces we found in the deep sea in this work. bacterial involvement in the decomposition of molluscan periostracum coatings in the abyssal depths has been documented (hook & golubic, 1988, 1990, 1992), eventually also progressing to destruction of shell carbonate (hook & golubic, 1993). thus, the microorganisms that form the base of the bioerosion process fall into two major metabolic categories regarding sources of energy (and carbon): phototrophs (autotrophs) and organotrophs (heterotrophs). phototrophs, such as photobacteria, cyanobacteria and eukaryotic algae, are light­dependent and thus restricted to the illuminated photic zone in the upper parts of the ocean. they were first studied in coastal environments (nadson, 1900, 1927; ercegović, 1932). later, it was suggested that phototrophic microbial endoliths (boring algae) could serve as palaeo­bathymetric indicators to enable the estimation of depositional depths in ancient seas (boekschoten, 1966), with proposed depth ranges based on experiences from modern environments (swinchatt, 1969). this hypothesis was important, because clues based on storm­related sedimentary deposition extend only to depths of a few tens of meters. below that putative water depth, most sediment is a fine­grained cover that leaves no distinction in the fossil record (brett et al., 1997). this suggestion stimulated further research (e.g., le campion­alsumard et al., 1982; wisshak et al., 2005), which proved a substantial underestimate of the proposed depositional depth ranges, because their originators did not consider the adaptations of benthic phototrophs to extremely low levels of submarine light. phototrophs were observed across the tidal ranges (le campion­alsumard, 1969; golubic, 1990) and shallow subtidal, typically down to 200 m water depth, though occasionally deeper (vogel et al., 2000; glaub et al., 2007), down to 300 m for the specialized chlorophyte ostreobium queketii and to 380 m for the cyanobacterium leptolyngbya (plectonema) terebrans (le campion­alsumard et al., 1982). depositional depth in ancient seas is estimated from the depth distribution of foraminifera (e.g., murray, 1973, 1991; bou­dagher­ fadel & price, 2010). foraminiferal tests in deep sea sediments are widely used substrates to study deep sea euendoliths – including in this paper. two of our authors, s.e. campbell and j.e. hook were the first to identify the absence of borings into foraminifera and pteropod shells while in the water column and that it only occurs following deposition at the benthos (golubic et al., 1984a). see also materials and methods and acknowledgements section of this paper for details. reef corals originate mainly through interactions between phototrophs and organotrophs – both in the polyps and in the coral skeleton. each coral species has a species­specific endolith composition, bioerosion rates and vertical zonation; the coral skeleton is inhabited by microbial endoliths during life, but the species composition of endoliths may change after the coral’s death (chazottes et al., 2009). the presence of endolithic algae may help corals survive bleaching events (fine & loya, 2002; pernice et al., 2020). however, there is some evidence of added damage by phototrophic microborings during bleaching periods (hassenrück et al., 2013). organotrophic eukaryotes, such as most bacteria, protists, fungi and animals, are independent of light and attack any form of organic material in the substrate, and as this work shows, sometimes as apparent parasites of other types of euendoliths. accordingly, they may occur at any depth, depending on the availability of organic nutrients, but their actual vertical depth distribution remains uncharted. the vertical distribution of microboring traces was studied in polar regions, where the euphotic zone is generally shallower (wisshak et al., 2005, wisshak, 2006, 2012, 2019; meyer et al., 2020). these studies determined that organotrophs dominated in deeper ranges starting with the settling of microborers. a kind of “succession” was noted in which microboring organotrophs were followed by dendrinids formed by endolithic foraminifera and related protistan borers. the present study, as in a few earlier ones (e.g., zeff & perkins, 1979), concentrates on the aphotic deep sea to completely exclude the presence of light­dependent microboring organisms from consideration. 1.3. marine microbial bioerosion is a benthic phenomenon we examined numerous shells and other skeletal carbonates of planktonic organisms, and never observed any microborings or etchings in shells of active plankton, something our research also confirmed previously (golubic et al., 1984a), as well as in the present study (see materials and methods below). the light­independent microboring organisms in the aphotic deep sea represent an overprint on deposited skeletal remains before they are buried by sediments and enter the fossil record g eo lo gi a c ro at ic a 196 geologia croatica 77/3 (campbell et al., 1983; golubic et al., 1984a). organotrophic microbial euendoliths exploit the organic compounds incorporated within the skeletons of molluscs (mao­che et al., 1996) and corals (priess et al., 2000). they exploit the organic matter incorporated by the host organisms (poulicek & jaspar versali, 1984) into their skeletons (price et al., 1976). these compounds include proteins (samata et al., 1999; kobayashi & samata, 2006) that participated in the organization of carbonate crystallites of the host’s shell (albeck et al., 1993; sarashina & endo, 2001; marin et al., 2005). concentrations of organic compounds in the bored substrate (e.g., organic lamellae) may influence the orientation of organotrophic euendoliths (mao­che et al., 1996; golubic et al., 2014). endolithic organotrophs were also shown to attack coral polyps, which respond by producing special cone­shaped skeletal protrusions in defense (le campion­alsumard et al., 1995b; bentis et al., 2000). so, the substrate can influence the microborers just as they influence the substrate. in addition to euendoliths, we describe patterns of extremely fine traces that are integrated into the substrate surface, which may be caused by endolithic components of epilithic foraminiferal, thraustochytrid or actinomycete food­ collecting systems. boring sponges, some of them microscopic in size (wisshak, 2008), consume microorganisms that are in suspension. thus, the organotrophic euendoliths, studied in different settings and depths (wisshak, 2008; golubic et al., 2014), may be indirectly supported by a broad range of primary production in the oceans. this includes phototrophy of the phytoplankton (uchman, 2007) raining down from the much shallower water column, as well as chemolithotrophy in the abyssal seeps and vents (paull et al., 1984; reysenbach & cady, 2001; gleason et al., 2017, 2019). chemolithotrophy was recently reported in fungi (gleason et al., 2019). 1.4. ichnology, the study of fossil traces in the present study we describe traces, found in deep sea dredged, grab, and core samples, in accordance with ichnological rules and regulations. our approach includes the understanding that traces are products of organismal behaviour, i.e., the results of growth and reproduction of microbial euendoliths. we employ the convention that their naming should reflect the shapes of the respective fossil traces (bertling et al., 2006; bertling, 2007; bertling et al., 2022; wisshak et al., 2019). we also pay attention to the influence of the substrate that is bored with respect to the endolith cast shape and texture, as this sometimes provides additional clues to the behaviour of the maker. descriptions of ichnotaxa were carried out on the assumption that traces of microboring organisms adhere to the morphology of their makers as has always been the case in modern endoliths, when makers are present, as well as in fossil populations preserved both as trace and body fossils (campbell, 1980). in our description of organism behaviour, we document how the interplay of the boring activity and substrate consistency may have influenced the morphology of the resulting traces. although most of the taxonomic descriptions are probably complete, in two ichnogenera, saccomorpha and orthogonum, additional investigation may be needed. there is a tradition in the study of trace fossils based on traces left in soft deposits, to identify them mostly as expressing animal behaviour (vallon et al., 2016), frequently concentrating on movement (plotnick, 2012), although both movement and growth in response to environmental stimuli are also known for plants and microorganisms. in the present contribution we found that the traces we describe originate from the behaviour of a specialized group of microboring organisms (bertling et al., 2006; miller iii, 2007a), while accepting the general definition of behaviour from the merriam­webster dictionary as “the way that a person, an animal, a substance” (or a microorganism) “behaves in a particular situation or under particular conditions” (endolithic). we confirm the view of bromley & nielsen (2015) who noted that bioerosion structures constitute ‘ready­made fossils,’ suggesting that the onset of fossilization be equated with the death of the bio­eroding trace­maker. in our ichnotaxonomy of deep sea microbial endolithic traces, we subscribed to the understanding that fossilization of microboring traces starts when the boring stops. the rules of ichnology require a strict separation of trace nomenclature and classification from the biological identity of trace­makers. yet, the distinction in behaviour of phototrophic vs, organotrophic microborers required identification of their physiological, i.e., biological properties. however, the distinction between phototrophic and organotrophic microboring organisms based on the morphology of their traces can be difficult because of trace similarities caused by convergent evolution (golubic et al., 2016). the behaviour of an organism may change depending on the condition, age, development and reproductive mode, resulting in different traces that may be preserved and persist in the fossil record. studies of microbial traces have intensified in recent years (seilacher, 1967, 2007; crimes & harper, 1970; frey, 1975; bromley, 1990; miller iii, 2007b; wisshak & tapanila, 2008; schönberg et al., 2019), but by design they have not included the biological identity of trace­makers. given its importance for palaeoenvironmental interpretation (see seilacher, 1967, 2007), avoiding bio interpretation is short­sighted in our view. we emphasize the importance of careful attention to sample collection to rule out post­depositional sediment slumping or other transport in modern as well as fossil studies. we discuss the need for additional research, including comparative research on extant prokaryotic and eukaryotic light­independent microboring organisms, that includes working out ichnotaxonomic descriptions of these fossil microborers in relation to their traces, as well as their vertical distribution along limestone coasts. such comparative research should be conducted to relate microbial assemblages and processes in skeletal fragments to those in the surrounding deep sea (may and perkins, 1979; schauer et al., 2010) as well as in fossil settings that are presumed to be deep sea sediments. in our view, descriptions of microbial ichnotaxa should result from analyses of fossil assemblages, and never be based on single g eologia c roatica 197golubic et al.: ichnotaxonomy of microboring traces in marine aphotic depths fossils. as new trace assemblages are discovered, some ichnotaxonomic revisions may be called for – as in this paper. understanding of how modern organisms create the tunnels that can be resin­cast and studied in comparison with casts of ancient microbial euendoliths, and using this knowledge in perspective, will inevitably result in better decisions about lumping and splitting taxa. lumping and splitting is always an issue when characterizing ichnotaxa and describing them. when consideration is given to what we can learn from the study of modern microbial endoliths, better ichnotaxonomic results can be obtained than if shapes alone are described. similarly, studying populations of modern and fossil euendolith casts will yield better information about variation within an ichnotaxon and among ichnotaxa. in this sense, biotaxonomic thinking is key to excellence in ichnotaxonomy of the microbial euendoliths. the present paper resulted from a decades­long multi­ investigator collaboration in the us, croatia, germany and involved samples from the mediterranean sea, the indian ocean, the red sea, and the atlantic ocean and represents the known deep sea microbial euendolith ichnofossil traces as well as including etches. we have sought to produce a quite comprehensive standard for comparisons against which future findings in various fossil sites can be evaluated. we also conclude that the aggregate activity of microboring organisms in the deep sea adds significantly to the overall global cycling of carbon due to the ubiquitous nature of the boring of sedimented shells in the world oceans. there is no information about the geographic distribution or about the diversity of participating microorganisms throughout the abyssal depths, owing to an almost complete lack of information about the biological identity of the microbial tracemakers and etchmark makers, other than that they are light independent. this research paper involves new and revised ichnotaxonomic descriptions. it includes the few previously described by others. in this way, in addition to being a research paper, this work also constitutes a monograph of all presently known deepsea organotrophic microbial euendolithic ichnotaxa. 2. materials and methods 2.1. sample collections all sediment samples in this study were obtained from professional oceanographers who carefully controlled the depth of sampling. all were verified as being collected far below the photic zone. samples reported on originated from between 600 m (campbell, 1982) to 2323 m depth (hook, 1991). the sand­size fraction of deep sea sediment dredged or obtained via grab or core sampling techniques was evaluated for evidence of endolithic tunnels. all sediment samples were obtained from sites free of sediment slumping, in order to rule out transport from shallower depths. autochthony and bathymetric accuracy were assured by the researchers who collected and/or provided the samples. samples were provided to stjepko golubic by robert hessler, from the deep sea collections of r. hessler and andrew benson, at station 299, at 2076m depth on an expedition of scripps institute of oceanography in the gulf of aden, indian ocean. that sample is close to the gulf of aden sample location of radtke outlined below. the scripps gulf of aden sample was studied with c14 at woods hole oceanographic institute by co­author james e. hook in 2024. the hessler and benson samples were found to be less than 1000 years old. fossil endoliths reported in this paper that stem from the 1991 phd thesis of co­author gudrun radtke are palaeocene or older. samples of oceanographic collections were dominated by fragments of pteropod shells and the tests of foraminifera that represent substrates for microboring traces. they were analyzed initially by dissecting microscope for the presence and shapes of microboring traces. deep sea samples dredged and/or grabbed from the northern mediterranean benthos at montpellier from 600 to 1500 m, were provided courtesy of d. belan­santini, station marine d’endoume, marseille, france in 1982 to s.e. campbell. these samples were primarily composed of foraminifera with other shell fragments of planktonic origin. figure 1a illustrates a representative sediment sample that came from the gulf of aden, red sea provided to g. radtke (details below). depth­controlled plankton samples presorted to supply a pure pteropod fraction, clearly holocene in age, were also provided to campbell 1982 in montpelier, france by j. rampal. the purpose was to determine whether any planktonic pteropods were attacked by microbial endoliths during passage through the water column, but there was no evidence of such activity. deep sea dredged, grab, and core sediment samples from the central atlantic grounds of the bermuda pedestal, at 1645 m depth were obtained by j.e. hook via the courtesy of t. sleeter, at the bermuda biological station (fig. 1a), as were the sediment samples from the south atlantic ocean (36⁰ 53’ s’, 53⁰ 10’ w) at 2195 to 2323 m depth to j. hook. the materials included foraminifera and other shells of planktonic origin. the following collections of the senckenberg expedition meteor 1987 in the red sea me5­158 port sudan, 1558 m depth, me5­176 ne masamirit 1970 m and me5­281 gulf of aden 1065 m deep were obtained by courtesy of ronald janssen, senckenberg research institute, frankfurt am main to g. radtke. 2012. dredged sediment samples from the red sea had outstanding shell preservation involving foraminifera, pteropods and other planktonic shells and shell fragments and provided a high ichnotaxonomic diversity (based on the review of 1100 photographs). preparation and sem documentation (senckenberg research institute) followed in frankfurt am main. and wiesbaden by g. radtke. all specimens from radtke (1991) and younger are deposited in the senckenberg collection. discussions, as a part of collaboration with max wisshak, senckenberg am meer, wilhelmshaven, germany, included comparison with samples he collected (wisshak et al., 2014b, 2018; golubic et al., 2014). 2.2. sample preparation shell fragments of fossil pteropods (fig. 1a) were selected using a dissecting scope from among other carbonate particles as a standard substrate for comparisons whenever possible. pteropod shells have the following properties suitable for this study: they are optically clear and of uniform thickness, g eo lo gi a c ro at ic a 198 geologia croatica 77/3 allowing for initial survey by light microscopy at various magnifications (figs. 1b; 2). the uniform internal structure of pteropod shells caused minimum substrate­related morphological alterations of the cast microboring traces, making them suitable for the purpose of comparison. it is usually impossible with direct visual observation to accurately characterize the nature of microboring traces within shells because of the shells’ natural opacity. also, we have found it necessary to study populations of each taxon to be able to work out which features typify it. this is never possible using direct light microscopy due to optical interference by the subtrate and overlapping traces. our solution to this problem has been to first embed the shell in resin (through a decreasing acetone dilution series) and then carve the resulting resin block to expose a circumference of the shell. at this point the sample is placed in dilute hcl or similar acid to dissolve the actual carbonate shell. this process can yield a replication of the tunnels to an accuracy of <0.1 micrometres. the two halves are metal­coated and observed and documented photographically under sem. the detail of the method of embedding is as follows: selected shells were dehydrated, infiltrated, and cast by multicomponent araldite resin or spurr low viscosity medium, following procedures of the combined embedding­ casting method (golubic et al., 1970, 1983; wisshak, 2006, fig. 5). the resin­casts were exposed by partially or completely dissolving the carbonate substrate by dilute hcl and observed as inverted (replicated) images of microborings. dissolution of the carbonate substrate is a necessary step in the technique to obtain resin casts of microborings for study by sem. this always results in destruction of the original material, so it is not possible to preserve type material of the actual microboring traces studied. for further discussion see section 2.4. as a control, scanning electron microscopy (sem) was used to observe the bored substrates directly (figs. 1c, d, and e) and we compared these with resin casts (figs. 1f, g). this approach permitted study of the trace orientation and the three­dimensional display of the borings within shells (färber et al. 2015). the close relationship between microbial borings and the bored substrate (golubic, 1969; golubic et al., 1975) was studied on deep sea traces using light microscopy and sem. the methodology employed in the study of microbial endoliths and bioerosion using complementary approaches has been summarized and illustrated in a separate publication (golubic et al., 2019). 2.3. measurements measurements of the dimensions of euendolithic traces that characterize their shape were carried out at the level of trace populations within mineralized substrates, using light microscopy and the sem of casts of microborings. dimensions were measured using motic­2 (motic group, china), sigma­ scan and sigma­plot software (jandel scientific, ca) and are displayed at appropriate resolution with the support of photoshop elements 18 (table 1). measurements of properties that appeared to be stable and uniform in appearance, while characterizing the shape of the trace, were carried out in natural populations of traces. the results were used for reconstruction of the 3­dimensional morphology of traces as proportions. traces with constant morphological properties, such as diameters of tubular traces, were expressed as mean ± sd (n = number sampled). structures subject to change, such as reproductive structures in the process of growth, were measured and recorded as ranges, emphasizing the maximum achieved rather than an average. this is a key distinction in the morphometry of microbial endoliths and casts of their borings – especially in the case of globe­shaped forms. ramifications were measured for branching frequency, with their orientation recorded. the branch diameters were recorded for separate branching orders (table 1). 2.4. ichnotaxonomy here, the observed trace morphotypes were identified according to formally described ichnotaxa. when these were lacking, the morphotypes were described as new ichnogenera and ichnospecies including their possible varieties. the existing ichnological nomenclature has been based on fossil traces (baucon et al., 2012). new descriptions and modification of ichnotaxa can be safely made on the basis of information obtained from borings found in deep sea sediments where the microboring organisms were no longer active (bromley & nielsen, 2015). when a new ichnotaxon is to be established, the type material should be fossilized, according to article 1.3.6. of the international code of zoological nomenclature (iczn, 1999, p. 3). as mentioned above, we accept the opinion of bromley & nielsen (2015) of what constitutes a fossil: “because bioerosion structures constitute ‘ready­made fossils’, it is suggested that the onset of fossilization be equated with the death of the bioeroding tracemaker.” accordingly, all our material should be considered fossil. we disagree with the proposal of bertling et al. (2022) to “define ‘fossil’ as ‘not demonstrably postdating the beginning of the holocene”. the arbitrary age of 11,700 years bp (walker et al., 2009) for the base of holocene is defined as the “first signs of climatic warming at the end of the cold phase” and does not have anything to do with being fossil or not. accordingly, we suggest that the proposal of bertling et al. (2022), that is not yet included in the code and cannot be used as a taxonomic rule at this time, be rejected in the future by the iczn. because “many trace fossils are diagnosed inadequately, either by incorporation of too many different forms, or by using such specific criteria that the ichnotaxon remains monotypic” (bertling et al., 2006, p. 265), some ichnogenera needed to be widened in this study to accommodate more ichnospecies (e.g., saccomorpha guttulata wisshak et al., 2018). some ichnospecies, when first described, included morphologically distinct developmental stages (campbell, 1980; radtke et al., 2010) and behavioural expressions, including at different developmental stages, which needed to be formally dis tin­ guished and separately named (plotnick, 2012). according to rules, the names of ichnotaxa rely on morphology and sub­ strate as ichnotaxobases, rather than on biological relationships among the trace­makers (bertling et al., 2006, 2019; bertling, 2007). however, in contrast to most other ichno­ g eologia c roatica 199golubic et al.: ichnotaxonomy of microboring traces in marine aphotic depths taxa, for microbial endoliths there is a very close relationship between the biological identity of a trace maker and its growth habit, which results in a trace that replicates the surface outline of the trace­maker (campbell & hoffman, 1979) in the vast majority of cases (see campbell & cole, 1984). we applied our knowledge about how to characterize the living microbial euendolithic taxa we have encountered in the course of extensive research of the photic zone and used this thinking in our approach to characterize the fossil deep sea ichnotaxa. we hope this type of work will eventually support identifying extant deep sea euendolithic tracemakers as well as any ancient body fossils that may be found within their traces. behaviour may change during growth, development, and the functional differentiation of individual trace makers, resulting in production of a variety of trace shapes, especially in those characterized as compound complex traces (miller iii, 2007a). in addition to morphological differentiation of the trace­making organism (oncogeny), how the trace was formed (ichnogeny) needs to be identified and discussed. with populations of microbial euendolith traces concentrated within very small fragments of shell or rock, such distinctions are possible within and among the ichnotaxa, with a high degree of confidence. despite the specific requirements of the ichnotaxonomic approach that differs from the biological one, in future it is likely that many biological trace­makers of these ichnotaxonomically characterized borings will be discussed, especially if this morphometric approach is applied at the population level, as a standard part of ichnotaxonomic work going forward which we regard as essential, although the taxonomic code does not require it. taxonomy requires that every extant or fossil species has its holotype (iczn 1999, p. 79). in the case of microboring traces, the technique necessary to obtain these traces involves, as a necessary step, the destruction of the calcareous sample (see section 2.2.). therefore, the holotype can be an image. it is specifically allowed under art. 73.1.4. of iczn (1999, p. 80): figure 1. shell and test fragments of pteropods and foraminifera settled on sediment and exposed to boring by deep sea microbial euendoliths (ca. 10x). a. sand-size fraction of the deep sea (1,553 m) sediment me-5-158 port said, red sea. b. a pteropod test selected from a., affected by a dense assemblage of microbial borings. c. fractured test of the foraminifer oolina globosa (montagu, 1803) with numerous perforations by microborers. d. detail of c, showing substantial expansion of the excavations in the interior of the test compared to small holes where endoliths entered. e. detail of the external oolina test surface in d, note the collapsed roof of a subsurface hyphal tunnel. f. substrate surface view from the test’s interior: resin-replicated neck of sacomorpha isp. with collar and attached hyphal tunnels (same scale as in e). g. microboring assemblage in a test of the foraminifer laticarinina pauperata (parker & jones, 1865), replicated in polymerizing resin. microborings of saccomorpha guttulata wisshak et al., 2018, interspersed with traces of saccomorpha ispp. g eo lo gi a c ro at ic a 200 geologia croatica 77/3 “designation of an illustration of a single specimen as a holotype is to be treated as designation of the specimen illustrated; the fact that the specimen no longer exists or cannot be traced does not of itself invalidate the designation.” photographic images are accepted as holotypes in nomenclature, if necessary. garraffoni & freitas (2017) discuss the use of photographs as type specimens, arguing that in the case of soft­bodied meiofaunal animals, specimens deteriorate and most of their diagnostic characteristics vanish soon after preservation, but sharp photographs and videos instead allow a timeless and correct identification. they suggest a revision of the code to speci fi­ cally allow this practice, as do we. 2.5. study procedures evaluating microbial endolith traces our approach to study deep sea euendolithic traces has been standardized as follows: visual inspection of selected translucent to transparent shell slivers provided the initial way of confirming the presence of microbial euendolithic traces (figs. 1a, b), followed by a survey using light microscopy, using consistent image scales as far as possible (e.g. in fig. 2, all scales are 50 µm long), to record and roughly compare the size ranges (fig. 2a vs. 2b) and size variability (fig. 2b vs. 2c vs. 2e), to determine the presence of ichnocoenoses (e.g. fig. 2d), and to evaluate the morphological complexity of individual traces (fig. 2f). owing to the importance of size distinctions when morphological features may have limited utility for taxonomic distinctions, we added a table of morphometrics (table 1) which serves as a type of comparative key. direct scanning electron microscopy (sem) is used to assess bioerosional damage to a substrate (figs. 1c, d, e). the three­ dimensional display of microboring excavations is best illustrated by sem of resin casts, following partial or complete dissolution of the carbonate matrix (figs. 1f, g), revealing their orientation and distribution within the bored substrates ­ in figure 2. outlines of various microbial borings in transparent shells from the 1550 m deep blake platform – transmitted light micrographs, all scale bars are 50 μm long. a. shell fragment densely bored by orthogonum isp. b. a network of crisscrossed hyphal tunnels interconnecting sporangial swellings of saccomorpha. c. outlines of saccomorpha guttulata, with ramified sections and spindle-shaped swellings; note dark content indicating residual organism or precipitate. d. a network of saccomorpha (1) superimposed over the shell surface corroded by scolecia serrata (2) and s. urbimetra isp. nov. (3). e. network of saccomorpha stereodiktyon, with numerous sporangia adhering to the shell’s interior surface. f. saccomorpha guttulata, in a transparent keel of the foraminifera laticarinina pauperata (parker & jones, 1865) from 1,645 m depth at bermuda pedestal, atlantic ocean. g eologia c roatica 201golubic et al.: ichnotaxonomy of microboring traces in marine aphotic depths which details of the contacts between endoliths and substrate can be examined (e.g. fig. 1f). this technique can be applied to modern and fossil euendolithic traces to evaluate the complexity and interrelationships among traces within the endolithic landscapes (e.g., fig. 3). microboring traces are evaluated by morphology and size, preferably at an angle to include the relationships between microborings and the substrate surface in perspective (e.g., figs. 4 and 5). the presence of conspecific or unrelated microboring organisms is documented, e.g. fusions of euendolithic tubules may reflect cases of accidental entering of the preexisting microborings, a biologically specific anastomosing property, a case of intraspecific mating behaviour, or interspecific host­parasite relationship. possible preparation artefacts are discussed in the interpretation of results. 3. results and discussion 3.1. photic zone endolithic landscapes these aspects of research are reviewed and summarized in the introduction section (above). within the ocean’s illuminated photic zone, both phototrophic and organotrophic euendoliths penetrate the skeletons of live and dead molluscs, calcareous algae, and corals (le campion­alsumard et al., 1995a; radtke & golubic, 2005, 2011), and are often nutritionally interdependent (le campion­alsumard et al., 1995b), summarized by tribollet et al. (2011a, b). the light intensity reduction and spectral modification follow the gradient of increasing depth (golubic et al., 1975, fig.12.2). however, the gradient also depends on the physical properties of the ocean water, which, in turn depends on its chemical composition and water purity. the depth distribution of light­ dependent organisms, on the other hand, depends on their physiological properties, i.e., light requirements. (le campion­alsumard et al., 1982). the subdivision of the illuminated zone of the ocean into euphotic and disphotic ranges is, therefore, arbitrary (glaub et al., 2007), and so are the palaeobathymetric estimates as reported and discussed in the introduction above. one obvious question is whether microbial endoliths could ever have been bored while the host skeleton was descending through the water column to the benthos. to test that, one of the authors accessed samples collected by a foremost pteropod researcher of the time, mme janine rampal in montpelier, france who assured all had been collected in the open ocean at discrete depths. thousands were evaluated in samples that had been collected from numerous depths in the open ocean and none were bored (unpublished research by susan e. campbell during a nato postdoctoral fellowship, 1982). 3.2. deep sea endolithic landscapes deep sea endolithic landscapes contain only light­independent, mostly organotrophic euendoliths which exploit organic compounds incorporated in the shells of molluscs and the tests of foraminifera (fig. 1a). many planktonic and benthic organisms produce organic­rich calcareous structures, which post-mortem become part of the sediment. these organic compounds are available as nutrients for organotrophic euendoliths (fig. 1b). the amounts of organic compounds incorporated into the mollusc shells is substantial. it may be as much as 5.5% of the shell’s dry weight, which amounts to over 40% of the entire organism’s organic matter being invested into its shell (price et al., 1976). it contains diverse proteins (marin & luquet, 2004; marin et al., 2005, 2007) and promotes calcification within organic lamellae such as is known in foraminifera (spero, 1988). thus, deep sea endoliths depend largely on distant extraneous primary production imported from the illuminated parts of the ocean above. the exceptions are those deep sea endoliths that colonize skeletons of organisms in productive deep sea gardens around hydrothermal vents and deep seeps (e.g., paull et al., 1984) which may depend on bacterial chemolithotrophy as their source of primary product (gleason et al., 2019). 3.3. carbonate excavation progression here, we examined endolithic excavation inside the test of the foraminifer oolina globosa montagu, 1803 var. saetosa earland, 1934 (see golubic et al., 1984, fig. 2c), by analyzing development of the perforation process. the endolith often enters the substrate through a tiny perforation, but subsequently excavates voluminous spaces in the interior of the substrate. there, some taxa develop elaborately branched tunnel systems. a fractured shell of the foraminifer oolina globosa, collected from more than 3200 m depth on the atlantic sea f loor (32º05’n, 64º15’w), provided the opportunity to examine the extent of bioerosion damage evident from the external surface view (fig. 1c), compared with the extent of excavation in its interior (fig. 1d). the volume of the cavities exposed by the fracture of the test was measured and compared with the volume of a cylinder as wide as the surface entry extending into the shell as deep as 50 μm (the average depth of euendolith penetration, see tribollet et al., 2011a). results showed that the volume of the substrate removed from the interior of the test marked by small entry openings was almost an order of magnitude larger (8.95 times larger) than the damage calculated based on the size of the euendolith’s surface entry, assuming the same average depth of penetration. this insight is significant in calculating and comparing the extent and rates of microbial bioerosion (e.g., chazottes et al., 1995, 2009). this leads to the realization that the microboring contribution to carbon cycling may be an order of magnitude larger than has been previously recognized. the study of the substrate and the interrelationship between substrate surface and microboring organisms requires a view from the outside (fig. 1e) as well as from the inside (fig. 1f). the interior landscape is best visualized by casting microborings in polymerizing resins then observing them by scanning electron microscopy sem (figs. 1f, g). it is important to view the behaviour of carbonate penetrating organisms in developmental terms, starting from the moment of the euendolith’s settlement and the initial entry into the rock or shell, and then by following the direction and changes of their boring strategy in the pursuit of shelter, nutrition, or reproduction. euendoliths’ responses may vary, depending on the stage of a taxon’s life cycle. they may be different in the vegetative state while seeking food than in the generative state pursuing reproduction. increase in branching g eo lo gi a c ro at ic a 202 geologia croatica 77/3 frequency has been observed when microborers approached organic lamellae inside the shell (mao­che et al.,1996). sporangial cavities frequently expand toward the substrate surface apparently to release the spores (figs. 4c. d). reconstruction of the developmental sequences of euendoliths from their fossil traces was possible in cases where the microboring traces were present in sufficient abundance to assess their morphological variability in relation to the structure and composition of the bored substrate. the shape and orientation of microborings, including avoidance of contact vs. anastomosis, are all indicative of sensing and responding, and have genetic control in the background of that behaviour. concentrations of organic compounds may have a positive effect on a euendolith’s orientation, while the mineral matter may represent an obstacle to its progress. we have observed deep sea endolithic landscapes (fig. 3d), where representatives of complex (a), tubular (b) and vermicular (c) euendolithic traces co­occur. morphometric properties of the studied deep sea traces are summarized in table 1. 4. systematic ichnology 4.1. complex traces in deep sea shells complex euendolithic traces are defined as products of organisms with biological complexity. miller iii (2007a, p. 461) discusses the distinction between compound and composite traces. only compound traces are legitimate and require description and naming, while the composite traces do not, because they may have been produced by more than one organism. they do require the identification of the components. euendolithic microborings may also constitute a cumulative historical record, involving more than one microboring organism. such cases would constitute composite, rather than compound traces, which require recognition but do not require naming (miller iii, 2007a). although some individual ichnotaxa illustrated here are located within larger groups of different ichnotaxa in a few photomicrographs, we carefully selected photomicrographs that unambiguously illustrate the type for each ichnotaxon described to ensure clarity. complex traces that are also compound are produced by specialized parts of the same organism. these distinct structural elements serve different functions and may change during the organism’s growth and development. the ichnogenus saccomorpha (radtke, 1991) from the tertiary of the lower rhine embayment, upper oligocene is a good example of a compound complex trace. 4.1.1. historical background the microborin gs of the saccomorpha type were first observed by george zebrowski within sand grains on an australian beach. he believed that he could recognize in this trace a lower fungus belonging to the family cladochytriaceae and described these forms as organisms, adding the customary latin diagnosis (zebrowski, 1936). zebrowski first presented his results at the 1934 meeting of the mycological society in pittsburg, pa, and subsequently described the new genus as dodgella, with the type species d. priscus and two other species d. inconstans and d. radicatus (zebrowski, 1936). zebrowski’s observations of biological structures were limited to fine, rarely branched hyphae inside shells and sponge spicules, proliferating from the spherical bases of the sporangia and radiating in fairly straight lines for distances up to several hundred micrometres, while remaining just beneath the substrate surface. he noticed that the sporangial swellings were positioned along the hyphae terminally or sub terminally, with the longitudinal axis at right angles to the hyphae, whereas the sporangial neck reached the shell surface, opening a pore to the outside. zebrowski also extracted the spores using dilute hydrochloric acid, and found that they stuck together forming a clump, as they would if released and settled on a new carbonate substrate. our specimen (fig. 2b) corresponds well to zebrowski’s descriptions and to his original drawings (zebrowski, 1936, pl. 27, figs. 1–4). 4.1.2. development of the tracemaker when a spore of the dodgella fungus settles on a carbonate substrate it germinates and forms a hypha, which subsequently penetrates into the substrate. further development can be recognized by following the boring trace that the hypha has left in the substrate. the sporangium forms in a terminal position on the hypha (fig. 3c, right). the hypha can subsequently continue with undifferentiated growth, leaving the sporangium in a subterminal or an intercalary position (fig. 3c, left). differentiation of sporangia starts as a minor hemispherical swelling of the hyphal tube, which deepens and expands to form the club­shaped cavity. the position of contacts between hyphal tunnels and sporangial swellings and the sizes of these swellings in the sequence along hyphal progression, indicate the direction of growth in the development of the tracemaking organism. spores that germinate inside sporangial structures appear to have produced tunnels that emanate from the sporangial cavity and continue on through the shell (fig. 3b, c). in modern taxa that produce similar structures, spores are released through the sporangial neck, transported through the water column, and settle on a new substrate, which they then penetrate following germination. furthermore, as sands and sediment shift in present­day seas, shells especially friable ones such as pteropod shells, will often fracture and break, especially in areas that are densely bored, which is a likely additional conduit of spores to the modern environment. similar fossil structures are likely to reflect an equivalent reproductive strategy by the tracemaker. 4.1.3. classification – the ichnogenus saccomorpha the original diagnostic features defining the ichnogenus saccomorpha radtke, 1991 were based on the type ichnospecies s. clava, holotypus bo 7/161 sophia jacoba 8 ii/ pecten. it is oligocene in age. the author contrasted it with two additional new ichnospecies s. sphaerula and s. terminalis (radtke, 1991, p. 92–98). the same author investigated trace fossils from the palaeogene (early tertiary) on the basis of mollusc shells from well­studied depositional areas, in order to demonstrate the bathymetric dependence of trace fossils and other environmental parameters. radtke (1991) established 7 new ichnotaxa with 19 ichnospecies based on extensive sample material, (circa 200 samples, 550 resin samples, 5500 g eologia c roatica 203golubic et al.: ichnotaxonomy of microboring traces in marine aphotic depths sem images). four ichnotaxa (orthogonum, saccomorpha, polyactina, scolecia) are relevant here. the size of hyphal tunnels for this ichnogenus was initially narrowly conceived and was later modified to accommodate more ichnospecies, by removing the diameter constancy of the interconnecting hyphal tunnels as an ichnogeneric criterion (wisshak et al., 2018). original descriptions of ichnospecies are usually based on limited observations of traces, which often include morphological variations without identifying their causes, such as changes due to growth, development, substrate specificity and behaviour, as well as the possibility of biological taxonomic distinctions. once these have been identified as expressions of ichnospecies behaviour, the conventions of trace fossil naming require that they be named separately. biological identity of the trace­makers is not part of the ichnotaxobasis, but it is helpful to distinguish between light­dependent and light independent trace­makers as well as their traces, when pursuing work in ichnotaxonomy. as our store of microbial endolith collections increased, a feature noted in 1991 on a small number of saccomorpha clava sporangial cavities, was a ring­shaped widening of the neck, which we perceived in resin­replicated specimens as a collar and was found to be more common than originally thought. because we regard the collar as a clear morphological distinction which is how an ichnofossil must be described, we are splitting trace 1, s. clava with no collars from trace 2, s. collaris with collars commonly seen in larger sporangia. we have recognized other additional distinctive features in saccomorpha such as a bent f lag sporangium, a lobate figure 3. microscopic landscapes with traces within a bored pteropod shell, displayed as resin-replicates. a. a population of traces of saccomorpha clava radtke, 1991 with sporangial swellings attached to the interior shell surface by necks that are interconnected by hyphal tunnels. b. two s. clava sporangia with hyphae attached to both sporangial bodies as well as the neck. c. proliferation of a sporangium of s. clava in subterminal position (left), with a hyphal tunnel extended from its sporangial body that probably resulted from germination of an unreleased spore. note the differentiation of another sporangial swelling in terminal position (right). d. euendolithic trace assemblage in a pteropod shell with the complex trace saccomorpha collaris isp. nov. (insert a), next to a large tubular orthogonum tubulare radtke, 1991 (insert b), both under a cover of a vermicular trace scolecia serrata radtke, 1991 (see also hook, 1991, fig 6-3.). e. s. collaris isp. nov. with two additional hyphal tunnels connected to the sporangial swelling (arrows). f. broken sporangial swelling cast with spores exposed. g. a group of expanding collared sporangial swellings of s. collaris isp. nov and tunnels. g eo lo gi a c ro at ic a 204 geologia croatica 77/3 sporangium, and a few others that we describe below as distinct ichnotaxa. ichnotaxonomists as well as biological taxonomists tend to be “lumpers” or “splitters.” sometimes this is mindset or viewpoint, but at other times, lumpers have identified features that are no longer deemed distinctive (e.g., wisshak et al., 2018), or they identify previously unrecognized transitions that undermine the original taxonomic distinctiveness. splitters may identify previously unrecognized features that proved to be distinctive when more examples were found. here, we encountered a need to split the saccomorpha ichnogenus into several ichnospecies. several morphologically distinct traces have been observed and described under different informal names, but were revised upon detailed comparative observations, and are reclassified within the ichnogenus saccomorpha: s. velum, s. radiata, s. stereodiktyon, s. papilio and s. guttulata. we start by summarizing saccomorpha clava (radtke, 1991) and then split it to yield s. collaris isp. nov. the first saccomorpha ichnospecies to be formally described, s. clava (radtke, 1991) is a complex trace comprised of club­shaped to pear­ shaped cavities connected by tubes. as with the chytridiomycote dodgella priscus zebrowski, 1936, the club­shaped cavities likely contained sporangia, whereas the tunnels probably were made by fungal hyphae. the sporangial function of these club­shaped cavities has been demonstrated in a few broken resin casts exposing spores (fig. 3f), and in fractured skeletal fragments (golubic et al.,1984a, fig. 2e, f). fossilized spores have been shown to persist for hundreds of thousands of years (campbell, 1980) and should be anticipated to be more frequent than vegetative cells in the fossil record owing to their generally protective, more robust cellular structure. trace 1: saccomorpha clava radtke, 1991 (figs. 3a­c) 1991 ‘plain dodgella’ – hook, 1991, p. 126, fig. 5­3 1991 saccomorpha clava isp. nov. – radtke, 1991, p. 92– 95, pl. 13, figs. 1­3, 5 1991 non saccomorpha clava (= saccomorpha velum isp. nov.) – radtke, 1991, p. 93, pl. 13, fig. 4 1991 non saccomorpha clava (= saccomorpha collaris isp. nov.) – radtke, 1991, p. 93, pl. 13, fig. 6 key feature: the simple variety of sporangial swellings (ca. 25 μm long, 15 μm wide and 10 μm thick) circular or elon­ gated in cross section. the name clava derives from latin clava, a club. the formal description as a trace with the name saccomorpha clava was given by radtke (1991, p. 92). radtke (1991) described the saccomorpha ichnogenus as a complex and compound trace comprised of club­shaped to pear­shaped cavities, on purely morphological grounds. names and terms that could indicate possible biological mak­ ers of the traces were deliberately avoided. the cavities expand from the substrate surface into the interior of the bored sub­ strate, perpendicular (less frequently slightly inclined to the surface plane). they are interconnected by uniformly thin 1 to 3 μm wide (except in s. guttulata, see table 1) with occa­ sionally branched tunnels. the length of the interconnection tunnels and the frequency of branching vary. the club­shaped cavities vary in shape and size. they are circular or slightly elongated in cross section. the size of the s. clava club­shaped cavities is age­dependent, reaching up to 25 μm in height (= penetration depth), and up to 15 μm in width, expanding in­ ward from the shell surface. in resin cast preparations, these cavities appear as pear­shaped bodies positioned on top of a narrower 6–8 μm wide stalk (neck) up to 20 μm long, erected from a planar interior surface of the shell (figs. 3a­c). comment: saccomorpha clava may represent early tran­ sitional states during the expansion of sporangial cavities. such smaller specimens of simple shape lacking a collar are often associated with morphologically different saccomorpha ispp, fig. 4f shows that situation with s. lobata. saccomorpha clava is the type species of the ichnogenus saccomorpha. it was described from the tertiary of the lower rhine embayment, upper oligocene, grafenberg formation, holotype bo 7/161, sophia jakoba 8, from a shell of pecten (radtke, 1991, p. 92–95, pl. 13, figs. 1–6; holotype image, pl. 13, fig. 1). as a part of the original description, this com­ plex trace was interpreted to be formed by the chytridiomycote fungus and compared with dodgella priscus zebrowski, 1936 (radtke 1991, p. 93). porter & zebrowski (1937) expressed a certain departure from biological classifi­ cation in favour of a classification of the observed borings as fossils, considering that their specimens might be of any age from the cambrian to recent, and that the organisms which produced the described pattern may or may not exist at the present time. well­preserved microboring traces are common in sand particles at all marine depths, although it is rare to find the trace­makers inside the boreholes except in the coastal in­ tertidal zone and in coral reefs. we have not found hyphal makers in their boreholes in the aphotic zone sediments, but we encountered spore­like reproductive units (golubic et al., 1984a). spores typically are tougher than vegetative cells that form hyphae and are far more prone to fossilize as previ­ ously mentioned. the interpretation that this complex trace was assumed to be formed by the chytridiomycote dodgella priscus ze­ browski, 1936, suggested that the club­shaped cavities con­ tained sporangia, while the tunnels contained fungal hyphae. the sporangial function of these cavities has been shown in broken resin casts exposing spores (fig. 3f), and in fractured skeletal fragments (golubic et al., 1984a, figs. 2e, f). the fine tunnels containing fungal hyphae that intercon­ nect the sporangial swellings are attached to them at the point at which the sporangial neck meets the shell surface (fig. 3c, left). they are less frequently attached anywhere on the body of the sporangial swelling (figs. 3b, c). the appearance of this feature is explained by spores germinating inside the sporan­ gium and then continuing to penetrate the substrate from there, instead of being released through the neck into the water col­ umn and settling and germinating elsewhere. a conspicuous feature observed in a few saccomorpha casts (radtke, 1991) is a ring­shaped widening of the spo­ rangial neck, observed in resin­replicated specimens as a col­ lar. this widening of the stalk into a collar is steep on the side of the swelling and gradual and conical toward the surface g eologia c roatica 205golubic et al.: ichnotaxonomy of microboring traces in marine aphotic depths (fig. 3b, c). it was noted as ‘not always present’ (radtke, 1992). it is a morphological feature that may also have had a biological origin. we now regard the collar as the key feature of s. collaris (see trace 2, below). when populations of this morphotype have numerous members with a well­developed collar and sporangia attaining larger sizes than described for s. clava, we recognize it as s. collaris isp. nov. (see trace 2). trace 2: saccomorpha collaris isp. nov. radtke, hook, campbell & golubic (figs. 3d­e, g, 4a) 1991 ‘collar dodgella’ – hook, p. 126, fig. 5­4 1991 saccomorpha clava ­ radtke, p. 93, pl. 13, fig. 6 holotype image fig. 4a; paratype radtke 1991, pl. 13 fig.6. etymology: latin collaris = equipped with a collar. key feature (diagnosis): the largest cavities have a “neck” with a collar (figs. 3d,e; 4a), suggesting a feature of maturity, however a few smaller cavities show collared necks suggesting an occurrence of the collar feature early in its process of development (fig. 3g). the largest cavities of s. collaris are 40 x 30 x 20 μm. in s. clava they are smaller. like s. clava, most of the sporangial cavities in the process of development lack collars (fig. 3a,b). comment: the collar around the sporangial neck is a feature marked as “not always present,” both in the original descriptions of dodgella priscus (zebrowski, 1936), and in the description of that trace as saccomorpha clava (radtke, 1991, p. 92). these observations raise the question of whether the collar is an expression of a taxonomically specific dis­ tinction, a feature expressed at a certain stage in the development of the sporangium, or a response to environmental conditions within the bored substrate, such as a structural obstacle in the process of penetration into carbonate? radtke (1991, p. 93, pl. 13, fig. 6) found isolated instances of collar in saccomorpha clava and included that in the clava description as a paratype. figure 4. saccomorpha ispp. traces. a. saccomorpha collaris isp. nov., sporangial swelling with collared neck connected to a hyphal filament at the base. holotype. b. s. curvata isp. nov. with a bent flag – note the etched shell surface around the sporangial neck attachment (see hook, 1991, fig. 5-4). c. saccomorpha polypoda isp. nov. connected by two necks with the substrate surface. d. s. polypoda with two necks and two additional protrusions; note that only the “primary necks” have collars (see hook, 1991, fig. 5-5b.). holotype. e. saccomorpha lobata isp. nov. with lateral lobes widening sporangial cavities that tend to fill the available space. holotype. f. s. lobata, detail; note the presence of two sporangia of s. clava morphology, possibly representing similar appearing earlier stages in development of s. lobata. g eo lo gi a c ro at ic a 206 geologia croatica 77/3 however, we now hold it to be indicative of a separate ichnospecies. collar presence is indicative of s. collaris. we observed that the sacs are initiated terminally or sub­ terminally as small hemispherical swellings on the interior surface of hyphal tunnels (fig. 3c, right). the connection of a sporangial swelling to the substrate surface is often accompa­ nied by a small area of etched substrate surface (fig. 4b). filaments interconnecting the sporangial cavities often encounter one another, but do not fuse and anastomose. most commonly, one of the filaments dives deeper into the substrate, bends under, and bypasses a preexisting one (fig. 5d). another response by the arriving filament is to stop short of the pre­ existing filament and form a terminal sac. thus, the hyphae act as primary and the sacs as secondary structures of this compound trace. the third type of response is deflection of the arriving filament and continuation of its growth parallel to the preexisting one. euendolithic hyphae seem to react to inhab­ ited and empty borings in a similar fashion. they persist in their endolithic mode and tend to develop groups of sporangial clusters when they encounter fissures in the rock or shell. this is likely where and how the ichnotrace creators released their spores in life. distribution: saccomorpha-type complex and compound traces are common in carbonate fragments on the deep sea floor and are widely distributed. they have been found in all the oceans examined from the intertidal to the abyssal depths. in habitats deeper than a few hundred metres these forms are usually dominant (fig. 3a). they have been reported in fossil substrates from the ordovician onwards (vogel & brett, 2009). the curved flag­shaped traces represent a distinct mor­ phology, and are possibly a product of a separate biological entity, so according to ichnological rules they deserve to be considered a distinct trace, which we name as saccomorpha curvata isp. nov. trace 3: saccomorpha curvata isp. nov. hook, radtke, campbell & golubic (fig. 4b) 1991 ‘bent flag’ – hook, fig. 5­4 1991 hook, fig. 5­12d holotype image: fig. 4b. etymology: latin curvatus = bent, curved. key feature (diagnosis): s. curvata is characterized by its curved flag­like shape, usually occurring in forms with a plain, non­collared stalk, ca. 25 μm long, up to 15 μm wide and only 6 μm thick. bending of the sporangial flag­shaped cavity cor­ relates with neither the thickness of the shell nor with any dis­ continuity observed in the shell's architecture. comment: the bending is considered an inherent mor­ phological characteristic, possibly an environmentally induced one. the morphological distinction of the curved flag­shaped sporangial cavity justifies the description of a separate ichno­ species. both collared and plain dodgella shapes with differ­ ent curvature have been seen in shells at 480 m depth by zeff & perkins (1979) as well as in all deep sea collections pres­ ently under study. the new species of saccomorpha curvata stems from the original observation of radtke (1991) that clava sporangial cavities includes some that are wide and flat, elongated in cross section, forming a straight, inclined, or bent “flag”. the flat­ tening and curvature of the flag are often combined, yet no correlation with the structure bored was observed. because of the conspicuous shape of this flag, we split it out in this paper as a separate ichnofossil. some sporangial swellings are connected with the sub­ strate surface by more than one neck. we recognize this fea­ ture as one worthy of a separate ichnospecies: trace 4: saccomorpha polypoda isp. nov. hook, radtke, campbell & golubic (figs. 4c, d) 1991 ‘multipedal dodgella’ – hook, p. 127, fig. 5­5 holotype image: fig. 4d. etymology: greek: poly = many, podos = leg. key feature (diagnosis): s. polypoda is a morphotype sim­ ilar in height to s. clava, but wider. each sporangial sac ex­ tends from a primary stalk with a collar and widens into an relatively isodiametric shape (30–40 μm in diameter), often with a flat top (fig. 4c, d). secondary, relatively wide tubular protrusions emerge from the main body of the swelling and connect to the substrat e surface without forming a collar. this results in bipedal and tripedal structures. additional protru­ sions that do not reach the surface are observed as projections from the main body (fig. 4d, right). comment: it is conceivable that the secondary stalks served as additional portals for the release of spores. the flat top may reflect the thickness of the shell. hyphae­containing tunnels (ca. 2 μm across) are connected to the swellings or to the stalks, and to the substrate surface. a different variant, distinct from saccomorpha clava, re­ fers to lateral lobate widening of the sporangial swellings, that develops from simple juvenile shapes and expands later by lat­ erally protruding sporangial lobes. this very characteristic shape of sporangial cavity deserves to be described as a new ichnotaxon: trace 5: saccomorpha lobata isp. nov. hook, campbell, radtke & golubic (figs. 4e, f) holotype image: fig. 4e. etymology: latin lobatus = lobed. key feature (diagnosis): s. lobata represents a different form of proliferation in which the sporangial cavity widens laterally, forming two to several horizontal lobes (golubic et al. 1984a, figs. 3d, e). this type of expansion often extends to a point of crowding, forming a layer of expanding sporan­ gial cavities, often occupying a large area. interconnecting hyphal tunnels are not different from those in s. clava. comment: s. lobata forms appear to develop from small simplex-type stages with the sporangial cavities expanding lat­ erally to occupy an area of the shell, often crowded, and mutu­ ally flattened as they develop into shapes resembling interlock­ ing puzzle­pieces or cookies in a pan as they swell during baking (fig. 4e) – swelling that expands later into a multi­lobed form (fig. 4f), covering areas up to 60 μm across. s. lobata type traces have been observed previously in the tests of foraminif­ g eologia c roatica 207golubic et al.: ichnotaxonomy of microboring traces in marine aphotic depths era exposed to boring in sediments of the atlantic ocean at depths of over 3000 m (golubic et al. 1984a, figs. 1e–h). the above four newly described ichnospecies have several prop­ erties in common with the saccomorpha clava as originally described, although they are also morphologically different. trace 6: saccomorpha velum isp. nov. hook, radtke, campbell & golubic (figs. 5a­b, d–e) 1991 ‘ic­dodgella’ – hook, p. 127, fig. 5­6b, d 1991 saccomorpha clava – radtke, p. 93, pl. 13, fig. 4 holotype image: fig. 5e top centre. etymology: latin velum = sail. key feature (diagnosis): s. velum consists of euendolithic traces with flat­based, sail­shaped intercalary, and arrowhead­ shaped terminal sporangial swellings, interconnected by straight hyphae­containing tunnels, 1.5 to 2.5 μm in diameter (slightly wider than those interconnecting sporangial swellings in s. clava), extending straight for long distances. intercalary sporangial swellings form along these tunnels 40 to 150 μm figure 5. saccomorpha velum isp. nov with arrow-shaped swellings along hyphae vs. s. radiata isp. nov. that lacks the hyphal swelling. a. light microscopic image of s. velum, showing the radiating boring pattern departing from a central group of distributive sacs and typical arrow-shaped terminal and subterminal swellings. b. the resin-cast replica of a similar distributive group of sporangia with radially departing hyphal tunnels and terminal arrowhead-shaped swellings. c. saccomorpha radiata isp. nov.; a single distributive sporangial swelling with six departing hyphal tunnels (one broken). holotype. d. saccomorpha velum with a sail-shaped swelling in subterminal position next to several tunnels bypassing each other, without fusion. e. an area of the interior shell surface dominated by a s. velum network of straight hyphal tunnels with sailand arrowhead-shaped sporangial swellings (see hook, 1991, fig. 5-6.). holotype top centre displaying sail shape g eo lo gi a c ro at ic a 208 geologia croatica 77/3 apart. the trace network usually starts from a central distribu­ tion centre composed of one to several sporangial swellings in a group (figs. 5a, b) connected with the substrate surface by a slightly inclined neck. less frequently, the network originates by spores germinating inside sporangia, producing several hy­ phal tunnels exiting in all directions from a single central iso­ diametric swelling, described below as a separate morphotype s. radiata (fig. 5c). the intercalary swellings are elongated, ca. 10 μm wide, up to 18 μm long and 10 to 12 μm tall (deep) adhering directly to the hyphal tunnels (without a neck) usu­ ally in the form of a flat upright sail (fig. 5d). the terminal swellings have a distinctive arrowhead outline (fig. 5a, b, and e, lower left). comment: the property of straight radiating filaments, combined with the distinctive sail­shaped and arrowhead­ shaped sporangial swellings distinguishes s. velum from other saccomorpha ispp. as recognized by light microscopy of an affected shell, (fig. 5a) and by sem of resin casts (fig. 5b). the morphological properties of this trace provide some in­ sight into the processes of development of this and similar traces. this morph, described here from the bermuda pedes­ tal, has not been previously reported, but may have been pre­ sent in photomicrographs published by zeff & perkins (1979, fig. 7). it has also been observed in material collected from the intertidal zone in the gulf of california. this mor­ photype may be more common but is difficult to distinguish from the more ubiquitous types of saccomorpha when using light microscopy or sem images in vertical projections. it is classified within the ichnogenus saccomorpha because it fol­ lows the basic pattern of resin­replicated sporangial swellings interconnected by fine filaments (tunnels). trace 7: saccomorpha radiata isp. nov. radtke, hook, campbell & golubic (fig. 5c) 1991 ‘part of the ic­dodgella morph’ –hook, figs. 5­6a, c holotype image: fig. 5c. etymology: latin radiatus = beaming or radiating. key feature (diagnosis): s. radiata produces a trace in which a single stalked swelling serves as a point of departure of hyphal tunnels exiting from the body of the sporangial swelling. solitary occurrences have been observed in early tertiary fossils, which remain the basis of this formal trace description (golubic et al., 2005, fig. 1d). however, we have observed the same morphotype as part of the development of the trace s. velum, as described above and s. guttulata (wis­ shak et al., 2018, figs. 2f–h; 3b, c). thus, it is possible that this morphotype expresses similar function and strategy in different saccomorpha­type traces or might even been part of the developmental sequence of s. velum. comment: the direct departure of many hyphal tunnels from the sporangial swellings, rendering them an apparent dis­ tribution centre, appears to be a strategy, beneficial to and pos­ sibly used by different complex organotrophic microorganisms. we cannot ascertain to what extent a particular occurrence is supported by the genetic background of the organism. how­ ever, our observations do confirm that the radiating pattern of the trace s. radiata fulfills an important function of distribu­ tion that is morphologically expressed and, thus we conclude it deserves to be described as a separate trace. zebrowski (1936, pl. 27, fig 4) described a similar chytridiomycete dodgella radicatus with subterminal sporangia 17–21 x 27–43 μm in size and mentioned up to 8 “rhizoids” to a sporangium, which may refer to radiating hyphae described here. trace 8: saccomorpha papilio isp. nov. hook, radtke, campbell & golubic (figs. 6a–f) 1991 ‘ptero morph’ – hook, figs. 5­8, 5­9 holotype image: fig. 6c. etymology: latin papilio = butterfly. key feature (diagnosis): s. papilio is the name for the trace characterized by flat sporangial swellings widened into two opposite lateral lobes that resemble the shape of a butterfly with spread wings (figs. 6a, b), diverging at angles between 45⁰ and 180⁰. alternatively, the swelling may fuse to form a semicircular disk with several shallow lobes (figs. 6c, d, e). the flat sporangial blade is itself anchored to the interior shell surface by numerous short (ca 2.5 μm long), thin (1 to 3 μm wide) tapered tunnels. on the opposite side, at the centre of the flat (the concave side) of the sporangial swelling is a spine (4–5 μm in diameter) extending toward the opposite shell sur­ face (usually broken in cast preparations) figs. 6b. several (typically 4–7) tapered, monopodially branched tubular exten­ sions originate between the swelling and the shell surface from a single centre, radiating in all directions (figs. 6a, c). the main filaments, resin­replicated tunnels departing from the central body arch mildly counterclockwise for the first few hundred micrometres (fig. 6c). they are initially 1–2 μm wide, and narrower with each subsequent ramification. these tu­ bules form an extensive flat network, covering an area of 1–2 mm in diameter (fig. 6a, c). the branching is monopodial and alternating, producing up to at least 7 orders of progressively thinner branchlets that adhere to the substrate surface, depart at an angle of about 70⁰, and run in remarkably straight lines. filaments taper and become progressively finer as they ramify. the main filaments have a diameter of 1–2 μm at the base (fig. 6d, e), while the finest branches are less than 0.1 μm wide (fig. 6f). the extremely fine filaments originate at all ramification orders, appearing to have been created by tunnel­makers densely exploring the area. very fine networks were observed to affect the substrate surface forming a small yet distinct etch­ field around the termini of these finest grooves (fig. 6f, insert). comment: the function of the spiny protrusion (fig. 6b) is unknown. it may represent the original entry of the micro­ borer but may also represent a neck for spore release. during the preparation process, it is conspicuous that, unlike resin­ casts of other very fine filaments, these networks remain in place following the carbonate dissolution process and are not displaced (compared to e.g., resin­cast tunnels in saccomorpha and scolecia). their stability indicates that they are integral parts of the substrate surface. they appear to be traces that are grooved into the shell and are probably epilithic in origin (fig. 6f). s. papilio is a complex trace. the microorganism that pro­ duces this trace is unknown, but the pattern of this ichnotype is reminiscent of foraminifera and thraustochytrids that are g eologia c roatica 209golubic et al.: ichnotaxonomy of microboring traces in marine aphotic depths characterized by having a central body from which emanates an extensive, fibrous cytoplasmic network, which serves to collect particulate matter and move it to the central body for consumption. the very close shell surface integration of this trace indicates that the trace­making organism may have fed on material falling onto the mineral shell surface rather than exploiting the organic matrix incorporated in the shell, or both. trace 9: saccomorpha guttulata wisshak & newmann, 2018 (figs. 1g, 2c, f and 7a–f) 1991 ‘the fusiform morph’ – hook, 1p. 131, fig. 5­7a, b 1991 orthogonum tubulare – radtke, p. 61­64, pl. 5, fig. 5, 6 2018 saccomorpha guttulata isp. nov ­ wisshak & neumann, 2018, p. 525­533 etymology: latin guttula = droplet. s. guttulata consists of a complex euendolithic trace sys­ tem of a relatively irregular, multiply branched network of round tubes that gradually increase in size to distally form swellings detectable by light microscopy (figs. 2c, f). we refer to this pattern as “sections.” in fully grown networks, the swellings are seen to be regularly spaced at distances of 30–80 μm and are the most frequent sites of branching. each cast sec­ tion starts with a filament of circular cross­section, 3–7 or 4.4 + 1.0 (n = 100) μm wide, gradually increasing to form distal swellings 20–40 or 21 + 5.5 (n = 131) μm wide and up to 60 μm long. in fully grown networks, the swellings are seen to be regularly spaced at distances of 30–80 μm and are the most frequent sites of branching. the swellings are fusiform but asymmetric, distally emphasized, creating an impression of droplets of different lengths (fig. 7a, b). the distal ends of sacs are commonly wider and often forked, producing two or more figure 6. saccomorpha papilio isp. nov. hook, radtke, campbell & golubic. resin casts (hook, 1991) of the butterfly-shaped and fan-shaped traces in a pteropod shell from the bermuda pedestal (1,645 m deep). a. internal surface area of a pteropod shell showing s. papilio: flat, butterfly-shaped sporangial cavity and expanding, branched, tunnels, narrower with each subsequent branching order (note scolecia urbimetra isp. nov. background, low centre). b. detail of a flat sporangial cavity of s. papilio with a neck and departing tunnels of different diameters. c. a fan-shaped sporangial cavity of s. papilio trace with radiating tunnels, distributed on the interior surface of a cracked pteropod shell. holotype. d. detail of c: note the texture of the swelling’s surface and filaments of different diameters. e. s. papilio swelling with some tunnels accompanied by s. clava. f. distal branching network of s. papilio tunnels: note the diameter difference between subsequent ramification levels. insert: terminal etching pattern of a s. papilio trace (see hook, 1991, fig. 5-8). g eo lo gi a c ro at ic a 210 geologia croatica 77/3 branches (fig. 7c) diverging at narrow angles. branching di­ rections may vary forming secondary distribution centres (fig. 7d, e,), but the growth of the network is largely directional, maintained at a level parallel to the substrate surface (fig. 7a, c). this system consists of distally enlarged sections that con­ form to the rhythm of branching by connecting the branch points. each section starts as a tube, which expands very grad­ ually, reaching a maximum diameter at the distal end of the section, followed by a steep decline in diameter, resulting in an asymmetric spindle (dimensions in table 1.). comment: the size distribution is supported by numerous morphometric evaluations (wissak & neumann, 2018, table 2). there is commonly a ramification and/or a contact with the substrate surface at the wider end of each section. less commonly, the sections follow each other in a linear fash­ ion (fig. 7b, top). see symmetric spindles (wisshak & neumann, 2018, fig. 2) and in linear arrangements (figs. 7b, right, c, top). more commonly, at the wider, distal end of the section, the diameter of the swelling is sharply reduced and associated with branching. trace 10: saccomorpha stereodiktyon golubic et al., 2014 (figs. 2e, 8a–c) 2014 saccomorpha stereodiktyon isp. nov. ­ golubic et al., p. 106, figs. 1­4 s. stereodiktyon is a three­dimensional (stereo) complex trace, with specialized parts that appear to have different func­ tions and different responses to the microecological composi­ figure 7. saccomorpha guttulata wisshak et al., 2018, a complex segmented trace (see hook, 1991) with gradual transition between proximal hyphal tunnels and distal swellings. a. dense segmented and branched network; expanding in the picture from right to left. b. young peripherally expanding filaments of s. guttulata; note the transition between the proximal tubules and distal asymmetric spindle-shaped swellings. c. detail from a (centre), with spaced ramifications of segments; note the presence of saccomorpha ispp. d. formation of secondary distribution centres of s. guttulata. e. detached cast of a sporangial swelling acting as a secondary distribution centre, with surface attachment (arrow). f. a branch of s. guttulata showing multiple connections to the substrate surface (see hook, 1991, fig. 5-7b.). g eologia c roatica 211golubic et al.: ichnotaxonomy of microboring traces in marine aphotic depths tion of the bored substrate. the trace consists of a network of hyphal tunnels with regular dichotomous and trichotomous ramifications that interconnect sporangial swellings (figs. 8a, c). the boring strategy is differentiated by two differently ori­ ented hyphal systems: a ‘horizontal’ and a ‘vertical’ network (golubic et al. 2014, fig. 5) the ‘horizontal’ network spreading parallel to the substrate surface (golubic et al. 2014, fig 1, 3), seems to be exploring the shell by spreading the filaments similar to the hyphae of a fungus). tubules are 1.0–3.0 μm wide, increasing in diameter approaching bifurca­ tions and trifurcations. sporangial swellings 15–30 μm or 22.4 ± 5.5 (n = 375) μm long appear to arise from tunnels at right angles to the surface and adhere to the internal substrate sur­ face (figs. 8a. c). a “vertical” network of hyphal tubes departs from the “horizontal” one by dichotomous or trichotomous ramifications (fig. 8b, centre), which swell slightly. each di­ chotomy generates one horizontal and one vertical branch. each trichotomy generates two horizontal branches and a third upright one. the upright branches penetrate toward the interior of the shell, where they apparently engaged in diges­ tion of organic lamellae incorporated in the shell, leaving a clearly discernable trace of that activity (golubic et al. 2014, fig 2g, h). comment: when encountering organic lamellae incorpo­ rated within the host’s shell, the upright branches, oriented perpendicular to the sub­surface network, form a special cloud­like optical disturbance, which is detectable by light mi­ croscopy (golubic et al., 2014, fig 1d). the same texture is figure 8. saccomorpha stereodiktyon golubic et al., 2014 (a-c) and polyactina araneola radtke, 1991 (d-g). a. s. stereodiktyon: sporangial swellings attached to the substrate surface interior, interconnected by a network of hyphal tunnels (note ultrafine tunnels may belong to a different microborer). b. s. stereodiktyon: dichotomous and trichotomous branches of hyphal tunnels (the scale in b is also valid for a and c). c. a sporangial swelling with a depression facing the interior of the substrate, insert: proliferation of conical excavations when hyphae encounter organic lamellae in the shell. d. transmission light photomicrograph of polyactina araneola radtke, 1991, in a transparent pteropod shellof a trace indistinguishable from conchyliaster enderi zebrowski, 1936, surrounded by saccomorpha ispp. e.-f. resin-replica of a p. araneola trace among traces of saccomorpha guttulata (sem images). g. detached p. araneola trace replica, showing the connection to the opposite shell surface (arrow). g eo lo gi a c ro at ic a 212 geologia croatica 77/3 revealed as an upward diverging set of interconnected spaces forming an inverted cone around the replicated hyphal tunnel (fig. 8c, insert). golubic et al. (2014) described reproduc­ tive branches that are often bent into flat helices as they pro­ duce terminal sporangial swellings at the substrate surface in an apparent reproductive phase of this trace­maker. the swell­ ings are cylindrical (fig. 8a, c) but also can be bi­lobate to multi­lobate (golubic et al., 2014, fig. 2e). the trace was first observed on marine underwater cliffs of the kornati islands in croatia at 70 m depth. later, it was found at different sites (couradeau et al., 2017; roush & garcia­pichel, 2020), including the intertidal zone of the north sea, but it is also frequent in shell fragments from the deep sea sediments of the gulf of aden in the red sea at 1558 m depth; early tertiary occurrences from the eocene have also been confirmed (radtke, 1991; golubic et al., 2014). by re­examination of the early work on the dodgella traces by zebrowski, we could recognize among his drawings (zebrowski, 1936, pl. 27, fig. 8) a similar trace of what he described as a cladochytriacean fungus arborella kohli ze­ browski, 1936. the ten ichnospecies listed above represent the presently known morphological spectrum of the genus saccomorpha radtke, 1991. trace 11: polyactina araneola radtke, 1991 (figs. 8d–g) 1991 polyactina araneola isp. nov. ­ radtke, p. 86­88, pl. 12, figs. 1, 2 p. araneola was described by radtke (1991). it was the type ichnospecies of the ichnogenus. polyactina is defined as being “composed of many radi­ ally branching arms” (radtke, 1991, p. 86­88, pl. 12, figs. 1, 2) and was compared with the trace of a cladochytrid lower fungus that fits the description for conchyliaster enderi ze­ browski, 1936. it is a complex trace with two types of sporangial swell­ ings. a central isodiametric cavity approaching 100 mm in diameter) apparently contains the primary sporangium, while several outward radiating cylindrical chambers may contain secondary sporangia. such secondary sporangial swellings are often separated from the central body by a slight constriction. the secondary sporangial swellings extend distally into long radiating and gradually tapering tunnels (fig. 8d), that are sig­ nificantly thicker than the adjacent hyphal filaments of saccomorpha ispp. the three­dimensional display of p. araneola cast in resin and viewed by sem shows the relationships between different parts of p. araneola, and some variation that is remi­ niscent of a small spider (figs. 8e–g). comment: the trace corresponds closely to the original description and illustration of conchyliaster enderi (ze­ browski, 1936, plate 27, figs. 7, 9), where it was described together with dodgella priscus zebrowski, 1936 as a sep­ arate microorganism. traces of both organisms are commonly found together (figs. 8d, e). the ichnogenus flagrichnus wisshak & porter, 2006, with the ichnospecies f. profundus (type) and f. baiulus were described as compound traces and marine cold­water in­ dicators (wisshak & porter, 2006, p. 135–145). they were distributed at depths that include the aphotic zone. a new species is described here that shares some but not all the prop­ erties of the ichnospecies above. trace 12: flagrichnus polyfloges isp. nov. hook, radtke, campbell & golubic (figs. 9a–c) 1991 hook, p.106­112; fig. 4­3., 4­4 holotype image: fig. 9b. etymology: greek poly = many; floga = flame. key feature (diagnosis): flagrichnus polyfloges isp. nov. consists of complex traces composed of a basal fairly isodia­ metric, sporangia­like swelling having multiple tapered, flame­ shaped to thread­like extensions that penetrate and permeate the shell (fig. 9a). the new trace shares several morphological properties with the type ichnospecies f. profundus (wisshak & porter, 2006, p. 139). similar to f. profundus and f. baiulus, the new ichnospecies has a simple isodiametric body ad­ hering to the substrate surface. unlike f. profundus and f. baiulus with simple and forked filamentous extensions (wis­ shak & porter, 2006, fig. 4), the new trace is beset by nu­ merous flame­like tapered extensions 2­3 mm wide at base, suf­ ficiently unique to be described as a new ichnospecies: f. polyfloges isp. nov. light microscopy (fig. 9a) shows the iso­ diametric outlines of the lobed sporangial swelling with numer­ ous tapered extensions, which fill the spaces between the sub­ strate crystallites they have preferentially dissolved (hook & golubic, 1993). adherence to the substrate surface and the flame­like shape of the extensions are best observed on sem images of resin­casts (figs. 9b, c). comment: our sem images of flagrichnus polyfloges isp. nov. (fig. 9b, c) compare well with f. profundus and f. baiulus regarding the adherence of the basal swellings to the substrate surface (wisshak & porter, 2006, fig. 2h). similarly, the tapered extensions emanating from the basal swelling (fig. 9c) in f. polyfloges correspond to the distal por­ tions of filament extensions of f. baiulus, (wisshak & por­ ter, 2006, fig. 3b) permeating the shell’s carbonate matrix. the borings of f. polyfloges dominated the interior of bathymodiolus shells collected at the florida escarpment at a depth of 3,266 m (paull et al., 1984). boring sponges have been known for well over two cen­ turies. fossil traces were named entobia bronn 1837 (schön­ berg, 2008; wisshak, 2008; wisshak et al., 2014b). wisshak (2008) described two ichnospecies e. micra and e. nana as parts of the microbioerosion in aphotic depths. in our study, we observed, characterized, and illustrated the fol­ lowing: trace 13: entobia micra wisshak, 2008 (figs. 9d, e) 1991 ‘knobby morph’ – hook, 1991, p. 138, 171; fig. 5–16 2008 entobia micra isp. nov. – wisshak e. micra or the mini­sponge trace is a complex trace characterized by the penetration and progression of sponge tissue forming a bumpy irregular, sometimes branched cylindrical body, approximately 200 μm in length and varying between 20 and 35 μm in width (fig. 9d). it is said to be g eologia c roatica 213golubic et al.: ichnotaxonomy of microboring traces in marine aphotic depths produced by a boring sponge that was noted to be much smaller than the known cliona type of boring sponges (wisshak, 2008). the trace is considered complex, as is its surface interface, as revealed by the casts. they consist of hemispherical knobs, averaging 5 μm across, at the points where the actual carbonate bioerosion takes place. some knobs appear in casts as open and hollow with a lip­like rim (fig. 9e). comment: the description above is consistent with the distinctive boring mechanism known for boring sponges, except that the size of this one is a full order of magnitude smaller. boring sponges have specialized cells, each of which removes substrate by encircling and separating a piece ca. 50 μm across, which is then exported to the shell exterior. the hollowed hemispherical knobs of this form would suggest removal of smaller than 5 μm diameter particles (see also “scalloping borer” hook & golubic, 1988). this morph has been observed in the deep sea sediment of the bermuda pedestal and in other sites of the northern atlantic (wisshak, 2008). 4.2. tubular microboring morphotypes tubular traces are simple, but also subject to a wide range of variability regarding the size, orientation in relation to the substrate surface, modes of branching, relationships to surface texture and interactive behaviour with other traces: avoidance vs. anastomosis. in the deep sea, different prominent traces often occur together: the complex traces of the ichnogenus saccomorpha (fig. 3d­a), tubular traces of the ichnogenus orthogonum (fig. 3d­b) and the thin and intertwined vermiculate traces of the ichnogenus scolecia (fig 3d­c). the tubular traces are described here. the ichnogenus orthogonum with the type ichnospecies o. tubulare radtke, 1991 was described as predominantly two­dimensional networks of robust, often rectangular, multiply branched tubular traces, extending parallel to the substrate surface, with frequent, often widened ramifications, which may cover areas of up to several mm². branching angles commonly approach 90º (40 % of measured angles are between 85º and 90º), which inspired its formal ichnogenus name: orthogonum. the trace has been formally described from a shell of turritella in the priabonian, upper eocene (radtke, 1991, p. 60, pl. 5, fig. 3 – holotypus bo 7/110). the original description of the type species o. tubulare radtke, 1991 included a wide spectrum of morphological variations, which may have represented the work of different microboring organisms. here, the genus is refined by modifying diagnostic criteria for o. tubulare and figure 9. complex deep sea traces flagrichnus wisshak & porter, 2006 (a-c) and mini-sponge trace entobia micra wisshak & neumann, 2018 (d and e). a. flagrichnus polyfloges isp. nov. – light photomicrograph taken through a translucent shell of the deep sea bathymodiolus sp. clam from the florida escarpment (3,266 m depth). characteristic are :isodiametric, sporangial cavities with tapered and fibrous hyphal extensions (see golubic, 1984b and hook, 1991 fig. 4-4.). b. resin cast of a f. polyfloges sporangial cavity in profile view, adhering to the interior of the shell surface, with branched and tapered extensions; the scale in b is valid for c. c. dome-shaped, partially collapsed resin-cast sporangial cavity and partially exposed intact cast with protuberances; (golubic, 1984b; hook, 1991 fig. 3-3. and fig. 4-4.). d. deep sea mini-sponge trace entobia micra wisshak, 2008, a branched tunnel with carbonate-carving functional units, each 4–5 μm in diameter (see hook, 1991, fig. 5-15c). e. detail of d: some of the carbonate-boring units are open outlining the size of carbonate chips carved by the e. micra sponge (see hook, 1991, fig. 5-15d.). g eo lo gi a c ro at ic a 214 geologia croatica 77/3 o. lineare and refining o. spinosum, as well as adding the species o. arbor, o. tenue, and o. cellexpressum. trace 14: orthogonum tubulare radtke, 1991 (figs. 10a–c; 11a–c) 1991 orthogonum tubulare isp. nov. – radtke, p. 60­64, pl. 5, figs. 3­4 1991 non orthogonum tubulare (= s. guttulata wisshak & neumann, 2018) – radtke, p. 61­64, pl. 5, fig. 5, 6 1991 non orthogonum tubulare, radtke, p. 61­64, pl. 6, figs. 1, 2 1994 non orthogonum tubulare – glaub, p. 98­100, fig. 35 the original description of o. tubulare is given by radtke (1991, p. 60­64, pl. 5, and now refers only to fig. 3 and 4). some former paratypes are now interpreted as other ichnotraces. updated diagnosis: a large tunnel system parallel to the substrate surface with thick, straight, and usually right­angled branched tunnels. the distances between branching points vary. the diameter of the tunnel can increase at branch points. updated description: the form is characterized by branching tunnels (diameter 8–15 µm), some of which run in a very straight line and occasionally appear to create wide arches. in the case of unilateral branching, right angles prevail, although angles between 20–60 degrees can be found. vertical branching into the shell is also present. some side passages branching off from the main passage, briefly turn deeper into the substrate to later arc back to the shell surface. often the branching points of the tunnels are conically thickened (diameter 20–30 µm). sometimes the tunnels show an oval, f lattened cross­section. anastomosis formation can be observed (radtke, 1991, pl. 5, fig. 3). in the description of orthogonum tubulare the author combined several observations into one ichnospecies, which occurred in different localities, which could finally be corrected here. some of the paratypes have now been assigned to other figure 10. orthogonum tubulare radtke, 1991, sem of resin-cast tunnels (sample raj 158-1a_29); also see sems in hook (1991). a. interconnected network of repeatedly ramified and periodically anastomosing tunnels of very variable diameters, branch length and location, distributed along the interior surface of a pteropod shell, shared with saccomorpha ispp. b. detail of a (upper left): showing moderately branched exploratory tunnels with several anastomoses. c. detail (centre): showing the range of size variability of ramified tubules of the same trace (see also hook, 1991, fig. 5-2d. and fig. 6-1.). photos b and c are at the same scale. g eologia c roatica 215golubic et al.: ichnotaxonomy of microboring traces in marine aphotic depths ichnospecies. a few specimens from northern italy and the aquitaine basin have since been assigned to the new ichnospecies saccomorpha guttulata wisshak, et al. 2018. a large number of specimens with very detailed observations were described by radtke,1991 (table 11, p. 62­64, 92 specimens). o. tubulare is a euendolithic trace that forms an extensive network of tubules within a skeletal carbonate substrate, characterized by high variability in diameter, branching frequency and considerably varied branching density as observed by light microscopy in transparent shell fragments (fig. 2a) and by sem of resin­cast replicas of tunnels (figs. 10, 11). the network exhibits, in part, a loosely configured “exploratory” phase (figs. 10a, left; 10b) with straight branches, relatively uniform in size, 16.5 ± 1.8 μm (n = 35) wide, becoming significantly wider (25–30 μm) and slightly flattened when approaching ramifications (figs. 10a, c) or anastomoses (figs. 10b, 11b). sometimes, the same microborer generates densely branched areas with branches that successively narrow in diameter, reminiscent of the ramification of branches of a tree, thereby forming a dense “substrate­exploiting” region (fig.10a, centre; 10c, 11c). branching occurs at various distances, 20 to 200 μm apart, and at highly variable angles (mostly less than 90⁰), with diameters ranging from 10 to 60 μm (fig. 11c). the network of the o. tubulare tunnels is largely two­dimensional, forming at one or two levels parallel to the substrate surface, with few branches departing deeper into the substrate (fig. 11d). the outlines of the tunnels are mostly irregular and the surfaces contacting the substrate are rough. comment: the original holotype figure of the ichnospecies o. tubulare radtke, 1991, p. 65, pl. 5, fig. 3 is confirmed. trace 15: orthogonum lineare glaub, 1994 – modified (figs. 12a–c) 1991 ‘cylindrical morph’ ­ hook, p. 131, 153; figs. 5­7c, d 1994 orthogonum lineare isp. nov. – glaub, p. 103, fig. 37 o. lineare consists of tubes of relatively constant diameter of 7 to 12 (9.96 ± 1.7, n = 59) μm wide (fig. 12a). this was previously described by glaub (1994) with diameter 7–16 µm, pl. 7, fig. 1–4.). o. lineare has a smooth surface and round cross­section (fig. 12c). ramifications occur at variable intervals, at nearly right angles (fig.12b) conforming to the ichnogenus diagnosis. tunnels have smooth surfaces (fig. 12b) and rounded, sometimes slightly inflated tips (fig. 12c). the lack of anastomosis and the avoidance of pre­existing tunnels is consistent, even when there is a high density of filaments. filaments arch over each other or are deflected (fig. 12c). tubules often run parallel to each other (glaub, 1994, fig. 37; pl. 7, figs. 2 and 4), avoiding the edge of the substrate as well as each other. in light­microscopic preparations, the tunnels were found to contain gray­coloured content. the sem of fractured tunnels shows some of our samples to contain spore­like bodies. comment: glaub (1994) describes the ichnospecies orthogonum lineare, mirroring the approach made by radtke (1991) for o. tubulare. glaub’s diagnosis, based only on the more narrowly defined description of o. lineare, lists clearly discrepant size ranges for what she regards as the same ichnotaxon. she appears to have studied them as populations but assigned those size ranges incorrectly. glaub documented her new ichnospecies based on a very idealized drawing (glaub, 1994, p. 103, fig. 37). also, her figure 11. orthogonum tubulare radtke, 1991, details. note the irregularity of branching pattern and the wide variety of branch diameters. a. regular branching pattern intermixed with saccomorpha network. b. anastomosis, detail from fig. 10b. c. example of a fusion of several branches with a wide range of branch diameters. d. branching with flat branch points showing avoidance of anastomosis. g eo lo gi a c ro at ic a 216 geologia croatica 77/3 drawing (p. 99) combines features from different taxa, which is a by­product of a “lumping” approach. for this reason, as well as the incompatible size ranges. o. lineare is being modified here. hook (1991) described o. lineare as the “cylindrical morph.” his size range matches our description. orthogonum lineare glaub, 1994 was described as a tubular microboring in the brachiopod linguithyris aspasia (holotypus: bo 13/203) as an ichnospecies with a predominantly straight (linear), frequently branched borehole system, characterized by tubules with smooth surface and rounded figure 12. tubular microboring traces of orthogonum lineare glaub, 1994, displayed as resin replicas (a-c) and o. spinosum radtke, 1991 (d-f). also see images in hook (1991). a. o.lineare spread over the interior surface of a pteropod shell fragment from 1,645 m deep bermuda pedestal sediment (see hook, 1991, fig. 5-7a.), with saccomorpha ispp. and scolecia in the background, left (see hook, 1991, fig. 5-15.). b. typical display of orthogonum-type filaments with orthogonal branching; note that the branches are often slightly narrower at the initiation. c. filaments of o. lineare, showing smooth surface and rounded tunnel tips, with saccomorpha ispp. in the background. d. light photomicrograph of orthogonum spinosum radtke, 1991 in a transparent shell together with saccomorpha ispp. and a tip of s. guttulata wisshak et al., 2018 (in the lower part of the photo). e. resin-cast of o. spinosum radtke, 1991. fig. 12d and e are at the same magnification. f. detail of e: at a different place, showing spines (see also hook,1991, fig. 6-4.). g eologia c roatica 217golubic et al.: ichnotaxonomy of microboring traces in marine aphotic depths tips. o. lineare is now modified to restrict it to one of the two originally mentioned size ranges: 7–12 μm wide. in contrast, glaub wrote that o. lineare encompasses populations between 7 and 16 μm diameter (glaub, 1994, p. 102). yet, the tables in that publication included in the original description list two size­distinct populations with diameters of 7–8 vs. 14–16 μm (l.c. p. 104). we found this ichnotaxon to avoid anastomosis (mentioned in the diagnosis), which explains the common deflection and parallel advancement of borings described by glaub (see glaub, 1994, pl. 7, fig. 3). the added information calls for modification of the diagnosis of this trace which appears to have initially encompassed more than one taxon with similar behavioural properties. trace 16: orthogonum spinosum radtke, 1991 (figs. 12d­f) 1991 hook ch. 6, p. 176, 187; fig. 4 1991 orthogonum spinosum isp. nov. – radtke, p. 65­66, pl. 6, figs. 3, 4 o. spinosum (radtke, 1991, p. 65­66, pl. 6, figs. 3, 4) or “spiny tubule” varies in diameter from 20 to 50 μm, producing a complex pattern comprised of two morphological elements: frequently branched tubules and pointed spinose extensions. the traces are clearly recognizable by light microscopy in transparent pteropod shells (fig. 12d), as well as in sem images of resin casts (figs. 12e, detail in f). the tubules’ shapes and sizes are both widely variable in diameter, including the flexible spiny protrusions which characterize this ichnotaxon (fig.12f). hook (1991, ch. 6, fig. 4) found similar tubes 30–70 mm or 33,5 ± 7.6 mm (n = 69). comment: we discovered that spiny tubules in the aphotic depths are relatively rare. our illustrated examples correspond to those in the original description of this trace (radtke, 1991, pl. 6, figs. 3, 4). trace 17: orthogonum arbor isp. nov. hook, radtke, campbell & golubic (figs. 13a–d) 1991 ‘arboreal morph’ ­ hook, p. 132, 153, figs. 5­10 holotype image: fig. 13b. etymology: latin arbor = tree. key feature (diagnosis): o. arbor is a solitary, relatively short, tubular form with a notable resemblance to a tree (fig. 13a). like a tree, it consists of a "trunk'' which terminates with a dense "canopy" of branches. the trunk begins its growth at the point of entry into the substrate and curves to continue to grow, mostly parallel to the shell surface, as a straight or gently arched tunnel for 100 to 600 μm. it is circular in cross section with a diameter of ca 10 μm, gradually increasing distally to 12 μm. it may sometimes ramify (fig. 13a) or change direction if encountering obstacles (fig. 13b). it mostly remains unbranched and mildly curved (fig. 13c). the "canopy" results from a burst of ramifications at the end of the straight "trunk," with an average branch point distance of 30 μm. the branching pattern is planar, sympodial, expanding up to 5 orders, with a circumference of about 150 μm (fig. 13a). the planar growth of the tree trace may be dictated by the thinness of the shell. departures of this pattern were noticed in thicker shells where the taxon develops a three­ dimensional canopy (fig. 13b). branches are up to 130 μm long, sometimes arched, and always shorter than the main trunk. their diameter is narrower at the branch point, and gradually widens distally, up to 50 μm, assuming a clavate shape. older branches also enlarge laterally, becoming flat and oval in cross section. as the widened branches fill most of the space between, they figure 13. orthogonum arbor isp. nov. in a pteropod shell from the bermuda pedestal (1,645 m deep); images in hook (1991, fig. 5-10). a. the tree-shaped microboring with a flat, two-dimensional canopy, spread parallel to the shell surface, with saccomorpha velum, isp. nov. (upper left) and other traces. magnification is the same as in c. b. o. arbor with a branches become gradually wider in the “canopy” region. holotype. c. early development of o. arbor with saccomorpha traces. d. o. arbor in the context of a dense deep sea ichnocoenosis with saccomorpha ispp. and scolecia urbimetra isp. nov. on the shell surface in the background. g eo lo gi a c ro at ic a 218 geologia croatica 77/3 crowd and become mutually compressed and rectangular in cross section. this trace is typically an integral member of the deep sea ichnocoenosis (fig. 13d). comment: images of o. arbor adhere closely to the substrate surface. this may be a result of displacement following removal of carbonate support. in that case, these borings may originally have penetrated deeper into the shell. during the examination of shell fragments, it was noted that the tunnels of this form weaken the shell, which then becomes particularly susceptible to breakage along this feature probably due to its propensity to tunnel close to the surface of the substrate. due to shell fracturing, the frequency of this trace in shell fragments may be underestimated. trace 18: orthogonum tenue isp. nov. radtke, hook, campbell & golubic (fig. 14a­a) holotype image: fig. 14 a­a. etymology: latin tenuis = narrow. key feature (diagnosis): o. tenue consists of narrow, very straight, rarely branched tubular traces, with irregularly wound, crowded terminals (fig. 14 a­a). lateral branches are short with attenuated ends. the main tubules are 5.5 to 10 (6.9 ± 1.35, n = 32) μm wide. comment: this trace needed to be described as separate orthogonum ichnospecies as it forms trace assemblages that are consistently narrow, and distinct from o. lineare. the main trunk diameter of o. tenue corresponds to the diameter of the secondary branches of o. tubulare radtke 1991. the trace was observed in the shell of the pteropod limacina. trace 19: orthogonum cellexpressum isp. nov. golubic, campbell, hook & radtke (figs.14a, b. detail: figs. 14b, ­c) holotype image: fig. 14b. etymology: latin cella = cell, expressus = distinct. key feature (diagnosis): o. cellexpressum trace is a prod­ uct of a highly variable microborer leaving tubular traces that appear to distally change in size and shape, possibly reflecting figure 14. tubular traces observed inside the shell of the pteropod limacina helicina phipps, 1774. a. tubular traces associated with saccomorpha ispp. along the interior surface of the shell. photo includes new ichnospecies orthogonum tenue isp. nov. shown to the left of label a (holotype) and o. cellexpressum isp. nov., the wider tubular trace in the region surrounding both label b’s. b. o. cellexpressum isp. nov.; note the surface bumps that could have resulted from a serial arrangement of rounded cells or spores inside. holotype. c. detail of b. g eologia c roatica 219golubic et al.: ichnotaxonomy of microboring traces in marine aphotic depths that the tracemaker was adapting to the immediate microen­ vironment. the trace was studied in the shell of the pteropod limacina (figs. 14a, b) where it occupied most of the skeletal subsurface. the width of the branches varies from 14 to 30 μm averaging around 20 μm (20.08 μm ± 3.69 μm; n = 46). the branches are often thinner at their base. in distal and expand­ ing parts of its system, the tubules are slightly wider and flat­ tened, elliptical in cross section, repeatedly branched as they adhere to the interior substrate surfaces of the host’s skeleton (fig. 14a, centre and right; figs. 14b, c). this type of branch­ ing is similar to that shown in o. arbor. the inward oriented surfaces of the branches show a series of bumps alternating with slight depressions about 15 μm apart, suggesting a series of cells in the interior causing the swellings along distal tu­ bules – similar to peas in a pod. comment: although highly variable regarding size, cross section, and branching pattern, the different interconnected parts seem to have been produced by the same organism. the boring activity appears to have progressed in two phases. the tubules are initially straight, narrow, ca. 10 μm wide, circular in cross section, remaining unbranched for long stretches (up to 500 μm) yielding an impression of exploratory tunnels. in a second phase, the tunnels branch, widen, flatten somewhat, and make an impression that growth slowed and differentiated a little. 4.3. vermicular microboring morphotypes vermicular trace morphotypes include narrow (<15 μm), winding, infrequently branched tubules formally described as the ichnogenus scolecia radtke 1991, with the type ichno­ figure 15. scolecia nodosa isp. nov. and associated coccoid traces in a pteropod shell from the 1,553 m deep sediment collection me5–158 at port sudan, red sea. a. accumulation of narrow and tapered filaments of s. nodosa with intercalary and terminally positioned nodules. the trace was originally more widely spaced, but it collapsed following the removal of the carbonate support by acid treatment. b. detail of a: showing tubular termini of s. nodosa, including distal curled branches with and without terminal nodules. c. a young colony of s. nodosa with diverging primary filaments next to a colony of coccoid-shaped depressions of the shell surface. d. s. nodosa colony that illustrates the characteristic tapering of filaments, with laterally positioned nodules. holotype. e. a colony with filaments tapered down to a submicron size with terminal nodules. insert: a representative sample of euendolithic coccoids showing the reproductive pattern of multiple fission. f. margin of a collapsed colony of s. nodosa with tapered filament endings. g eo lo gi a c ro at ic a 220 geologia croatica 77/3 species s. maeandria radtke, 1991, from the lutetien, eo­ cene of paris basin (radtke 1991, p. 70­76, pl. 7, fig. 6, pl. 8), with three additional ichnospecies: s. filosa, s. serrata (trace 24) and s. botulifera. the present study of deep sea eu­ endoliths yielded a new discovery: a distally tapered or nodu­ lated vermicular trace described here as scolecia nodosa isp. nov. this resulted in the slight modification of the original ge­ nus diagnosis to include distal attenuation and formation of nodules as described below (compare with hook, 1991, p. 134­138, as ‘vermicular morphs’). trace 20: scolecia nodosa isp. nov. radtke, hook, campbell & golubic (figs. 15a–f) holotype image: fig. 15d. etymology: latin nodus = knot, swelling. key feature (diagnosis): s. nodosa or “nodulated vermic­ ular” boring is a euendolithic, intensely proliferating trace with long, filamentous, distally tapered microborings having a smooth surface and numerous lateral and often terminal nod­ ules. the trace consists of tunnels (filaments in resin­casts) with diameters of about 1 μm, tapering distally down to a di­ ameter of less than 0.1 μm (fig. 15a). the branching of s. nodosa is uncommon, with an increased frequency toward the terminal parts of the filaments where the last generation of branches are tightly curled (fig. 15b). the growth of s. nodosa starts in the form of a cluster of diverging round­tipped fila­ ments (tunnels, fig. 15c) and is later associated with nodules (figs. 15b, d, e), which finally occur on filaments or on the fila­ ment terminals (figs. 15d, e). however, the attenuated termi­ nals also often remain free of nodulation (fig. 15f). nodulation is the most intriguing property of this trace. nodules are either integrated into the filaments in a terminal position (fig. 15b, e) or are laterally attached (fig. 15d). nodules also group in­ dependently in the vicinity of a filament (fig. 15e, insert). comment: scolecia nodosa isp. nov. is by dimension and surface features somewhat similar to s. filosa (radtke, 1991, pl. 8, fig. 3). it differs from s. filosa by nodulation and terminal attenuation (tapering). the true euendolithic nature of the organism producing this trace is evident during the car­ bonate dissolution process of specimen preparation. these rep­ licas of fine tubules become dislodged during the acid treat­ ment. they float in the solution and collapse as the solution drains or evaporates and accumulate resembling a pile of spa­ ghetti (figs. 15a, d, f). only in young s. nodosa bunched short filaments still in contact with the substrate surface is their ori­ entation vertical to it (fig. 15c). the very small diameter tu­ bules are similar in size to finely etched grooves that are in­ corporated into the substrate surface. the resin­cast tubules remain in place after acid treatment, as we have observed for the finest branches of the complex trace saccomorpha papilio (see trace 8 above) and for substrate­bound traces of s. urbimetra isp. nov. (see trace 25 below). there are two possible explanations of the extensive ag­ glomerations of coccoid shapes that have been regularly ob­ served in the vicinity of this trace (figs. 15c, d, and e­insert). one is that they represent sporulation and the onset of daugh­ ter colonies. alternatively, there could have been host­parasite interactions. these coccoids vary in size as if they are organ­ ized into colonies – reminiscent of cyanobacteria that display reproduction by multiple fission; however, the fact that these traces are attached to hard grounds in the aphotic deep sea rules out cyanobacteria which, except for very few taxa, are light­dependent. the morphology and size suggest that the casts could belong to organotrophic bacteria with a cell divi­ sion pattern similar to that of cyanobacteria. whether there is any relationship between these coccoid­like units and the ones attached as nodules to the filaments of s. nodosa is not known. given that we have not seen them anywhere else, it is likely there is some relationship between them. close association of ultra­fine scolecia­type filamentous traces with complex and tubular deep sea traces are sugges­ tive of submicroscopic parasitic predation involving other members of the endolithic community. several additional mor­ photypes of such fine tubular structures were observed as resin­replicates by high magnification and resolution sem mi­ croscopy. two of the morphotypes were sufficiently regular and frequent to be described as new trace ichnospecies within the filamentous ichnogenus scolecia radtke, 1991: scolecia hirudo isp. nov. and s. acus isp. nov., both represent mi­ crometre­sized borings associated with larger traces, sugges­ tive of host­parasite relationships. trace 21: scolecia hirudo isp. nov. radtke, hook, campbell & golubic (figs. 16a, c, g) 1991 hook, p. 163, figs. 5­12c holotype images: figs. 16 g. etymology: latin hirudo = leach. key feature (diagnosis): s. hirudo consists of ultra­fine, filamentous traces that are up to 20 μm long, only a fraction of a micrometer wide, terminally tapered to submicron dimen­ sions, associated with much larger sporangial cavities of saccomorpha ispp. some of these ultra­fine tunnels are straight or mildly bent, attached to the saccomorpha hyphal tunnels (fig. 16a), or distributed over the sporangial swellings of saccomorpha ispp, either as repeatedly branched (fig. 16c) or as densely curled and tapered (fig. 16g). comment: ultra­fine tubular traces require further inves­ tigation. no relationships among the observed morphologically different properties of the traces of s. hirudo and the traces they were attached to could be established, and the biological iden­ tity, reproduction and dissemination all remain unknown. in addition to these flexible and curved ultrafine microborings, several different types of needle­like ultrafine structures were also found associated with larger deep sea euendolithic traces. trace 22: scolecia acus isp. nov. hook, campbell, radtke & golubic (figs. 16b, d, e) 1991 ‘needle morph’ – hook, p. 135, 163; figs. 5­16 holotype image: fig. 16b. etymology: latin acus = needle. key feature (diagnosis): s. acus in its simplest form refers to a short, straight ultrafine tubular, ca. 4 μm long and 0.1 to 0.2 μm wide needle­like structure, with a minor, slightly de­ tached and curved terminal swelling (fig. 16b). these were g eologia c roatica 221golubic et al.: ichnotaxonomy of microboring traces in marine aphotic depths originally termed “pinheads” (hook, 1991). they are loosely distributed and adhere to the interior substrate surface (fig. 16d, bottom). it is not clear whether these very small objects are depicted in their original positions, or whether they were displaced and redeposited in the process of dissolution of car­ bonate, and/or by surface tension forces exerted during evapo­ ration in preparation for scanning. the second type of ultrafine needle boring morphology, observed in situ, refers to needles that provide connections between larger endolithic traces and the internal substrate surface. s. acus is often connected with larger swellings and tubular microboring traces by its pointed end and attached to the substrate surface by a forked end at the opposing terminus. two sizes were observed, the larger ca. 13 μm long and < 1 μm wide (fig. 16d, right), and numerous smaller ones, similar in size to the above described “pinheads” (fig. 16e). the third type, consisting of ultrafine needles was ob­ served to be attached to relatively large isodiametric depres­ sions with crystalline outlines, described as trace 23. trace 23: scolecia stellaris isp. nov. hook, campbell, radtke & golubic (fig. 16f) 1991 ‘starburst morph’ – hook, p.137, 171; figs. 5­16b holotype image: fig. 16f. etymology: latin stellaris = star. from the original description of ‘starburst’ in hook (1991). key feature (diagnosis): these short (<10 μm long) and 0.3–0.5 μm wide filaments are polarly attached to crystal­ shaped casts. they appear to be scattered on the interior of the substrate surface. scolecia stellaris, in its initial stages, (see small tubes with triangular heads), is similar to the pinhead boring in 16b, d, and is likely a further developmental state. the triangular head widens into a larger angular, crystal­like swelling. detailed observations reveal a certain degree of serration outlining even the finest scolecia tubules (e.g., fig. 16d). this morphology reflects the chemical interaction between the mi­ figure 16. scolecia hirudo isp. nov. (a, c, g) and s. acus isp. nov. (b, d, e, f). both ichnotaxa have tiny micrometre-sized borings associated with larger traces, suggesting host-parasite relationships. a. ultrafine filaments probably of s. hirudo, attached to hyphal tunnels at the base of a sporangial swelling of saccomorpha curvata isp. nov. b. submicron size pinhead-shaped traces of s. acus, each with a terminal swelling, scattered on the interior shell surface. holotype. c. branched ultrafine filaments of s. hirudo adhering to a detached sporangial swelling of s. clava. d. inclined needle-shaped tubule similar but larger than s. acus leaning on s. curvata sporangial swelling, forked at the contact with the shell surface, and surrounded by smaller pinhead-type needles (as in b.) scattered over the inner substrate surface. e. s. acus comprised of numerous ultrafine inclined rods, forked at the base, connecting tubular traces with the substrate surface. f. s. stellaris isp. nov traces consist of scattered isodiametric holes with crystalline outlines, attached to ultrafine up to 10 µm long tubules. holotype. g. ultrafine tapered and wound filamentous s. hirudo borings curled at their tips, associated with the sporangial swelling of saccomorpha clava. holotype. g eo lo gi a c ro at ic a 222 geologia croatica 77/3 croborer and mineral substrate, which characterizes scolecia traces that all have serrated outlines (discussed below). comment: vermicular traces with serrated crystal­shaped outlines, described as scolecia serrata radtke, 1991 were frequently observed in deep sea samples. we note that when­ ever scolecia displays a serrated surface, it exhibits three dis­ tinct morphotypes: two planar and one three­dimensional. the serrated surface is the key characteristic of this group of traces. accordingly, the name and description s. serrata radtke, 1991 is retained and modified for that euendolithic borer, hav­ ing a three­dimensional display when it penetrates into the in­ terior of the substrate. the traces that differ in relation to the substrate, i.e., that are also integrated into the substrate’s sur­ face, represent different behavioural patterns, and are described as a separate ichnospecies: scolecia urbimetra isp. nov. trace 24: scolecia serrata radtke, 1991 (figs. 2d(2), 17a, b, c & d (left side)) 1991 ‘vermicular morph’ – hook, p. 134, 161; fig. 5­11 1991 scolecia serrata isp. nov. – radtke, 1991, p. 74. pl. 8, fig. 4 s. serrata was described as a very narrow, tightly wound and intertwined, infrequently branched vermicular boring trace, with a serrate outline (radtke, 1991, p. 74. pl. 8, fig. 4), found in the interior of mollusc (pteropod) shells. the tun­ nels are 2 to 4 μm in diameter, seen as tightly wound filaments when cast in resin (figs. 17a, b, c, d left side). the serration stems from etching or the complete removal of crystallites comprising the shell interior, via microbial biocorrosion of the host shell (fig.17b). these submicron­size etched grooves are replicated in resin as submicron size serrations on the filament. figure 17. vermicular traces with serrated surface outlines: scolecia serrata radtke, 1991 (a-c, d left), (see also hook, 1991, fig. 5-11.) and s. urbimetra isp. nov. (d-right, e, f) (see hook, 1991, fig. 5-13.). a. very densely packed tunnels of scolecia serrata radtke, 1991, located close to the substrate surface overlain by orthogonum and saccomorpha. b. a cluster of scolecia serrata with serrated outlines close to the shell surface. it is euendolithic on the margins of the cluster. the centre of the cluster is incorporated in (appears interwoven in) the substrate surface. also note how flat it is. c. the trace s. serrata, tightly wound covering the surface of a pteropod shell. d. s. serrata (left) and s. urbimetra isp. nov. (right) on the surface of the same pteropod shell; note the difference in size and spacing. e. detail of the trace s. urbimetra shown in d (right). f. direct sem image of the pteropod shell surface bio-corroded by s. urbimetra. the biocorrosion produces trenches outlined by the removal of aragonite crystallites. figs. e and f are at the same magnification. g eologia c roatica 223golubic et al.: ichnotaxonomy of microboring traces in marine aphotic depths comment: the dimensions above, and in the original de­ scription involve “serration”, i. e. substrate crystallites re­ moved lateral to a much thinner vermiculate microborer. the minimum width ranges from 0.5 to 1.2 μm, with a maximum width, including serration up to 3.8 μm (see also radtke and golubic 2005, fig. 4d). the 2­dimensional traces, which are integrated in the substrate also appear as surface etching. trace 25: scolecia urbimetra isp. nov. hook, radtke, campbell & golubic (figs. 2d(3), 17d upper right, e, f) 1991 ‘city map’ morph – hook,, p. 136, 165; fig. 5­13 holotype image: 17d upper right. etymology: latin urbs = city, metro = measure. key feature (diagnosis): s. urbimetra morphotype is com­ posed of a shallow, regularly spaced, and branched trace, rem­ iniscent of a city map (figs. 2d (upper right), 17e, f), which is integrated into the substrate surface. the replicas show a ser­ rated outline of the network of grooves that are more sparsely branching. direct sem of the attacked pteropod shell (fig. 17f) illustrates that the lines created by the trace are, in fact, grooves etched into the carbonate shell, and their serrated ap­ pearance reflects the removed aragonite crystallites of the shell. these trenches are quite uniform and narrow 1.08 ± 0.25 μm (n = 123) wide. branches occur either as alternate or op­ posing, with no apparent regularity, leaving large unaffected areas of the shell surface between them. the branching angle is variable, monopodial over smaller surface areas and sym­ podial over larger surface areas. the distances between branch points are extremely variable, ranging from 7 to 150 μm. the tracks often bend or suddenly change direction, rarely remain­ ing straight for any distance (fig. 17d­right). comment: continuous tracks show avoidance by bending away from each other. when crowded, the filaments usually form a tight, terminal "j" shaped hook. this morphotype is rarely solitary, mostly occurring in groups of several separate networks. tracks and branches sometimes appear discon­ nected, showing short, but distinct gaps. this suggests an in­ terruption of boring in which the trace­maker bridged the gap as an epilith, and then continued its trench excavation without abandoning the trace it had started. a similar case of a surface­ bound trace has been recently presented by wisshak et al. (2018), demonstrating the activity of an epilithic crawler that periodically sent branches into the substrate below. sem close­ up imagery was necessary to document the direction of pene­ tration. the causative agents of scolecia ispp. with serrated outline remain unknown. the consistent distinction in the shape and distribution pattern between s. serrata (fig. 17d left) vs. s. urbimetra (fig. 17e right) suggests strongly that biologi­ cally different microorganisms produced these traces. compare also figures 2d­c and 13d, where s. urbimetra creates a unique substrate­bound etch pattern that serves as a backdrop to eu­ endolithic traces. both s. sigillum and s. urbimetra are micro­ scopic grooves carved into the shell surface. the pattern ob­ served bears resemblance to that reported for actinobacteria, particularly those involving open loop or hook­type sporula­ tion. marine actinobacteria have only been demonstrated and studied recently (valliappan et al., 2014). trace 26: scolecia pluma isp. nov. radtke, hook, campbell & golubic (figs. 18a­c) 1991 ‘bottlebrush’ morph ­ hook, p. 137, 167, fig. 5­14 holotype image: fig. 18b. etymology: latin pluma = feather. key feature (diagnosis): s. pluma is a trace found slightly below the surface of pteropod shells. hook (1991) called it “bottlebrush” (fig. 18b) owing to the rod­like central filament with perpendicular extensions. the study of the development of this trace showed that it starts as a tunnel (a resin­cast fila­ ment), less than 1 μm in diameter, which conforms to the cri­ teria identifying it as a member of the group of scolecia traces (fig. 18b). the later development observed along the scolecia tunnel is seen in resin replication as flat foil­like lateral exten­ sions, which under light microscope appear fuzzy and golden in colour resembling feathers, which suggests the name s. pluma. the main axes curve horizontally, are on average 70– 80 μm long and surrounded by numerous extremely fine “downy” extensions (ca 0.1–0.2 μm wide, up to 10 μm long) departing at right­angles from it, as well as penetrating deeper into the substrate (fig. 18c). the main axis forms a submicron sized tunnel that determines the progression of the trace. comment: in the cast preparations, the lateral processes appear flat, probably consisting of thin, tapering resin­foils replicating the intercrystal spaces, widened by lateral carbon­ ate dissolution. this morph has not been previously reported, and the biological affiliation of the causative agent remains unknown. 4.4. etching patterns on deep sea carbonate surfaces carbonate substrates are known as firm settling grounds for many sessile and mobile benthic organisms. attachment and anchoring may affect the substrate and leave a trace of such attachments. this habit has been identified in the classification of traces under the group name podichnia (miller iii, 2007a). we encountered several forms of shallow etched areas marking the shell surfaces that are likely generated by differ­ ent and unrelated mechanisms. these traces are probably left by the anchoring components of epilithic organisms but may also have other origins. these patterns are conspicuous, so we were obliged to describe them as a new ichnogenus; vestigichnus igen. nov. with the type ichnospecies v. discus isp. nov. which consists of slightly depressed areas on the substrate surface with exposed crystalline patterns of the shell mineralogy. they can be distinguished as disk­shaped and ring depressions in the substrate surface. such traces are charac­ teristic. they are described as trace 27. trace 27: vestigichnus discus isp. nov. radtke, hook, campbell & golubic (figs. 18d, e, g, h, i) 1991 ‘plaque pit’ hook, p. 137; fig. 5­15 holotype image: fig. 18d. etymology: latin vestigium = remain, latin discus = disk shaped. g eo lo gi a c ro at ic a 224 geologia croatica 77/3 key feature (diagnosis): v. discus or “plaque morph” (fig. 18d, centre) consists of shallow circular lens­like depressions, up to 100 μm in diameter but only a few micrometres deep. two superimposed well­expressed and preserved circular plaque traces with sharp etch marks expressed are illustrated in an sem image that includes views of the resin­cast surface replicas of a pteropod shell (e.g. 18d, centre), and finer detail (fig. 18e). the detail shows that the etch patterns conform to the mineral organization of the shell with exposed outlines of the crystal boundaries of the shell substrate. comment: the surface etchings in fig. 18d form a back­ drop over which deeper boring traces are superimposed, in this case orthogonum tubulare radtke, 1991 as well as several colonies of the complex trace of saccomorpha ispp., with hy­ phal tunnels and sporangial swellings. the detail in fig. 18e shows two such traces and a spindle shaped swelling between two rounded sporangia of orthogonum fusiferum radtke, 1991 (p. 66­67, pl. 6, figs. 5, 6), a trace attributed to the fungus ostracoblabe implexa (bornet & flahault, 1889; eck­ blad & kristiansen, 1990). comparison can also be made with other studies of endolithic fungi (mao che et al. figure 18. etches. etching patterns observed on the resin-replicated internal surfaces of pteropod shells are made by scolecia pluma isp. nov. (a-c) (see hook, 1991, fig. 5-14.) vestigichnus discus igen. nov. et isp. nov. (d, e, g, h, i) and v. annulus isp. nov (f) (arrows). a. scolecia pluma isp. nov., a delicate feather-like euendolithic trace replicated by resin, consists of a widespread winding system of shallow traces, distributed beneath the substrate surface; composed of a filament, surrounded, and covered by foliose side branches perpendicular to the filament. b. detail of a: showing the scolecia filament bordered by a two-dimensional submicron diameter downy extensions. holotype. c. detail of b: view of resin-cast feathery extensions. d. vestigichnus discus isp. nov., shown as two superimposed, slightly depressed etch-fields (centre) possibly caused by attachments of epilithic organisms (hook, 1991, fig. 5-16a.). a surface biocorrosion marker forming a background to deeper borings of orthogonum tubulare radtke, 1991. e. detail of d: mineral patterns by overlapping vestigichnus etch fields behind hyphal tunnels and sporangial swellings of saccomorpha simplex isp. nov. and orthogonum fusiferum radtke, 1991. f. resin replica of an orthogonum tubulare boring with ring-shaped etch-fields (arrows; holotype) of vestigichnus annulus isp. nov. around the contacts of the tubular boring with the substrate surface. g. several superimposed circular etchmarks. h. linear arrangement of overlapping circular etchmarks, suggesting directional displacement of an epilithic causative agent. i. a thin euendolithic tunnel leaving a long trail of its surface travel in the form of an elongated etching field that widens. g eologia c roatica 225golubic et al.: ichnotaxonomy of microboring traces in marine aphotic depths 1996, fig.6). a series of vestigichnus annulus units with over­ lapping margins (fig. 18g) can be understood as a time­series of epilithic settlers. a similar time­series of vestigichnus units in a linear arrangement, (fig. 18h), suggests directional move­ ment of such a causative entity. furthermore, a trace connected to fine tubular microborings, (fig. 18i), documents convinc­ ingly such etch­related dynamics. it could possibly reflect epi­ lithic growth or even “crawling” that was faster than the circu­ lar expansion of the etch­field where it overlaps with penetration of a scolecia–type tunnel entering the shell’s interior. trace 28: vestigichnus annulus isp. nov. radtke, hook, golubic & campbell (fig. 18f – arrows) 1991 ‘ring pit’ – hook, p. 137; figs. 5­16b, d holotype image fig. 18f – arrows. etymology: latin annulum = ring. key feature (diagnosis): v. annulus or the ring­shaped morphs up to 150 mm diameter, are similar to v. discus plaque morphs and can be smaller or larger than the typical disk­ shaped etch­fields. they consist of a depressed ring with a cen­ tral area that remains elevated (not shown), or which is occu­ pied by a different structure, e.g. a sporangial neck or similar contact of traces to the substrate surface (fig. 4b). vestigichnus­ type etch fields have been observed associated with euendoliths contacting or exiting the substrate. the selected example shows a well­developed tubular euendolith orthogonum tubulare radtke, 1991, that penetrated the substrate, parallel to its surface and generated two connections that exited the sub­ strate, both surrounded by a halo of v. annularis etchings (fig. 4b; 18f, arrows). the etching seems to have occurred over time. comment: large ring pits (up to half a millimeter in di­ ameter, not illustrated) need more research. they may repre­ sent damage left from a holdfast attachment of a stalked ani­ mal, or of a foraminifer. we were able to demonstrate similar circular depressions formed on the shell surface following the microbial destruction of periostracum (hook & golubic, 1993, fig. 1b). the circular depressions extend deep enough to loosen the intercrystal matter of the shell and are sufficiently extensive to be recognized as a widespread removal of carbon­ ate. much larger traces named neodendrina, which are pos­ sibly caused by foraminifera or by attachment of algae (wis­ shak & neumann, 2018, figs. 3f–i), were not observed in our collection. a much smaller, somewhat elongated ring trace has been recently identified as the attachment trace of a sessile diatom (wisshak et al., 2014a). 4.5. summary of ichnotaxonomic evaluations some previously established ichnotaxa addressed in this study needed to be modified as required by the nomen clature and classification systems of traces – to maintain the trace identity as the expression of the behaviour of an unknown potential trace­maker. certain excessively narrow constraints introduced in the original description of ichnogenera were modified to accommodate newly discovered ichnospecies (wisshak et al., 2018). a few ichnospecies, too widely conceived in their original descriptions, proved to include more than one behavioural expression, and needed to be subdivided. complex­compound euendolithic traces, have been re­ cognized as products of organisms with biological complexity (miller iii, 2007b). they consisted mostly of interconnected traces produced by vegetative vs. reproductive functions of the same trace­making organism. they have been found within the ichnogenera saccomorpha radtke, 1991, polyactina radtke, 1991, and flagrichnus wisshak & porter, 2006. the complex trace saccomorpha clava radtke, 1991 is accepted as in the original description, represented by speci­ mens considered complete with sporangial cavities and a collar around the sporangial neck. traces that are morphologically distinct from that morphotype were described as a separate new ichnospecies. the most frequent morphologically distinct traces without a collar, are saccomorpha collaris isp. nov., and s. radiata isp. nov. and were described as new ichnospecies after consideration of whether these forms could represent undifferentiated developmental stages of one or more micro­ boring organisms. the following four previously established ichnospecies categorized as complex traces have been observed in the aphotic deep sea: s. clava radtke, 1991, s. stereodiktyon golubic et al., 2014, s. guttulata wisshak et al., 2018, and polyactina araneola radtke, 1991. eight ichnospecies novae are described and added to com­ plex­compound ichnospecies (7 to the ichnogenus saccomorpha radtke, 1991): s. collaris isp. nov., s. curvata isp. nov., s. polypoda isp. nov., s. lobata isp. nov., s. radiata isp. nov, s. velum isp. nov., s. papilio isp. nov., as well as one new ichnospecies flagrichnus polyfloges isp. nov. described within the ichnogenus flagrichnus wisshak & porter, 2006. tubular and vermicular traces consist of a single biological element, usually conforming with the outline of the trace­ maker’s body. among tubular traces, trace diversity within the ichnogenus orthogonum radtke, 1991 includes the three established, although variable ichnospecies orthogonum tubulare radtke, 1991, o. lineare glaub, 1994, and o. spinosum radtke, 1991. we add three new ichnospecies: o. arbor isp. nov., o. tenue isp. nov., and o. cellexpressum isp. nov. significant distinctions were also observed among simple vermicular i.e., worm­like filamentous traces of the ichnogenus scolecia radtke, 1991: s. serrata radtke, 1991 is shown to include etching as well as boring. five new ichnospecies are presented: s. nodosa isp. nov., s. hirudo isp. nov., s. acus isp. nov., s. urbimetra isp. nov., and s. pluma isp. nov. the vermicular traces with serrated outlines, originally described as scolecia serrata radtke, 1991 are now recognized to include euendolithic and/or surface etchings. we describe one new ichnospecies with serrated outlines that are integrated (etched) into the surface of the substrate: s. urbimetra. this drew attention to etching patterns on the substrate surface, which resulted in the description of 1 new ichnogenus: vestigichnus igen. nov. with 2 ichnospecies: v. discus isp. nov, and v. annulus isp. nov. g eo lo gi a c ro at ic a 226 geologia croatica 77/3 ta bl e 1. m or ph om et ric s of th e ic hn ot ax a. t he m or ph om et ric ta bl e is n ee de d be ca us e si ze s of th e fe at ur es o f e ac h ta xo n ca n be d ia gn os tic . h av in g a co nd en se d m or ph ol og ic al d es cr ip tio n ca n he lp d is tin gu is h si m ila r si ze ic hn ot ax a. it s er ve s a s a n id en tifi ca tio n ke y. tr ac e n o. ic hn oge nu s ic hn os pe ci es d es cr ib ed b y fi gu re n o. h ol oty pe sh or t d es cr ip tio n of tr ac e m or ph ol og y d im en si on s co m po un d tr ac es ig en . s ac co m or ph a ra d tk e 19 91 n /a sp or an gi al s w el lin gs in te rc on ne ct ed b y th in u ni fo rm b ra nc he d tu be s h yp ha l t ub e ø in m m sw el lin g l x w x d in m m 1 s. c la va ra d tk e 19 91 3a – c 3b cl ub -s ha pe d sw el lin g w ith c on ne ct io n ne ck la ck in g co lla r & h yp ha l c on ne ct io n 1 2 ; 1. 5 ± 0. 51 (3 8) 2 5 x 15 x 1 0 2 s. c ol la ris is p. n ov . r a d tk e et a l. 1f , 3 d – g, 4 a 1f cl ub -s ha pe d sw el lin g w ith a c ol la r a ro un d th e ne ck c on ne ct io n 1 2 ; 1 .2 7 ± 0. 22 (6 8) 4 0 x 30 x 3 0 3 s. c ur va ta is p. n ov . h o o k et a l. 4b 4b fl at te ne d an d cu rv ed c lu bsh ap ed s w el lin g an d ne ck w ith ou t c ol la r 1 2 2 5 x 15 x 6 4 s. p ol yp od a is p. n ov . h o o k et a l. 4c ,d 4d is od ia m et ric c lu bsh ap ed s w el lin g w ith m or e th an o ne n ec k 1. 5 2 .2 4 0 x 30 x 3 0 5 s. l ob at a is p. n ov . h o o k et a l. 4e ,f 4e w id en ed a nd fl at s w el lin g w ith la te ra l l ob es , o ft en c ro w di ng 1. 5 2 .2 5 0 x 50 x 3 5 6 s. v el um is p. n ov . h o o k et a l. 5 a – e 5e sa ilsh ap ed in te rc al ar y an d ar ro w -s ha pe d te rm in al s w el lin gs , n o ne ck 1. 0 2 .5 1 8 x 10 x 1 2 7 s. r ad ia ta is p. n ov . r a d tk e et a l. 5c 5c ce nt ra l s ph er ic al s w el lin g w ith n ec k an d ra di at in g na rr ow tu be s 2. 0 ± 0. 9 (4 60 ) 2 5 x 20 x 2 0 8 s. p ap ili o is p. n ov . h o o k et a l. 6a – f 6c fl at s w el lin g pa ra lle l t o su bs tr at e su rf ac e. t ub e di st al ly n ar ro w in g ta pe re d 5 t o < 1 < 10 0 x 60 x 5 9 s. g ut tu la ta w is sh a k et a l. 20 18 2c ,f; 7 a – f n /a sp in dl esh ap ed s w el lin gs in te rc on ne ct ed b y di st al ly w id en in g tu be s 6 -7 (4 .4 ± 1 .0 ) ( 10 0) 21 .4 ± 5 .5 (1 31 ) 10 s. s te re od ik ty on g o lu bi c et a l. 20 14 8 a – c n /a cy lin dr ic al o r l ob ed s w el lin gs te rm in al o n tr ic ho to m ou s b ra nc he d tu be s 1. 0 3 .0 15 -3 0; 2 2. 4 ± 5. 5 (3 75 ) 11 po ly ac tin a ar an eo la ra d tk e 19 91 8 d – g n /a ce nt ra l a nd c yl in dr ic al ra di at in g sw el lin gs e xt en de d by ta pe re d tu be s n /a n /a 12 fl ag ric hn us po ly flo ge s is p. n ov . g o lu bi c et a l. 9a – c 9b sw el lin g ap pr es se d to su bs tr at e su rf ac e w ith fl am elik e ex te ns io ns 2. 0 3 .0 40 x 3 0 x 40 13 en to bi a m ic ra w is sh a k 20 08 9d ,e n /a th ic k st ra nd s o f c lio na -t yp e ca rb on at eca rv in g ro un de d un its , s om e op en a t t ip 10 20 5 x 5 x 5 tu bu la r t ra ce s tu be s o f d iff er en t i n si ze a nd b ra nc hi ng p er pe nd ic ul ar to p ar al le l t o su rf ac e ig en . o rt ho go nu m ra d tk e 19 91 14 o rt ho go nu m tu bu la re ra d tk e 19 91 10 a – c; 1 1a – c n /a tu be s u ni fo rm in d ia m et er , s m oo th w ith ro un de d tip s 12 -1 8 (1 6. 5 ± 1. 8) (3 5) n /a 15 o . lin ea re g la u b 19 94 – m od ifi ed 12 a – c n /a tu be s o f r el at iv el y co ns ta nt d ia m et er , m os tly sm oo th su rf ac e an d ro un de d tip s 712 (9 .9 6 ± 1. 7) (5 9) n /a 16 o . sp in os um ra d tk e 19 91 12 d – f n /a tu be s v ar ia bl e in d ia m et er , c ov er ed b y m an y sp in y ex te ns io ns . 20 to 7 0 (3 3. 5 ± 7. 6) (6 9) n /a 17 o . ar bo r is p. n ov . h o o k et a l. 13 a – d, 1 3b 13 b tu be s s ta rt si m pl e th en b ra nc h; b ra nc he s d is ta lly w id er 10 -1 2 ; 1 250 n /a 18 o . te nu e is p. n ov . r a d tk e et a l. 14 a – a 14 aa tu be s c on si st en tly n ar ro w er a nd s tr ai gh te r t ha n ot he r d es cr ib ed 5. 410 (6 .9 ± 1 .3 5) (3 2) n /a 19 o . ce lle xp re ss um is p. n ov . g o lu bi c et a l. 14 a – b, c 14 b tu be s d is ta lly w id en ed a nd fl at te ne d w ith su rf ac e bu m ps 14 to 3 0 (2 0. 1 ± 3. 69 ) ( 46 ) n /a ve rm ic ul ar tr ac es tu be s t hi n an d w in di ng , r ar el y br an ch ed , o ft en c on st ric te d or ta pe re d ig en . s co le ci a r ad tk e 19 91 pr ox . d is t. 20 s. no do sa is p. n ov . r a d tk e et a l. 15 a – f 15 d tu be s t ap er ed , s m oo th , w ith la te ra l a nd te rm in al g lo bu le s. 1. 0 to < 0 .1 n /a 21 s. hi ru do is p. n ov . r a d tk e et a l. 16 a, c, g 16 c tu be s e xt re m el y fin e. a ss oc ia te d w ith o th er b or in gs l ik e pa ra si te s 0. 5 to < 0 .1 n /a 22 s. ac us is p. n ov . h o o k et a l. 16 b, d, e 16 b, f ex tr em el y fin e tu bu le w ith te rm in al s w el lin g lik e "p in he ad " 0. 10. 2 w id e by 3 -5 l on g n /a 23 s. st el la ris is p. n ov . h o o k et a l. 16 f 16 f ex tr em el y fin e tu bu le s a tt ac he d to c ry st al -s ha pe d sp ac es (b od ie s) 0. 5 to < 0 .1 n /a 24 s. se rr at a ra d tk e 19 91 17 a, b, c 18 b tu be s t ig ht ly w ou nd w ith s er ra te d m ar gi ns in si de th e su bs tr at e 12 (4) n /a 25 s. ur bi m et ra is p. n ov . h o o k et a l. 17 e – rig ht , f , g 17 f, g su rf ac e gr oo ve s r eg ul ar ly sp ac ed , t hi nn er ; b ra nc he s a t 4 5 9 0 de gr ee s 1 2 ; 1 .0 8 ± 0. 25 n /a 26 s. pl um a is p. n ov . r a d tk e et a l. 18 a, b, c 18 b sh al lo w g ro ov es p ro du ce d b y la te ra l, ta pe rin g fo ils a lo ng th e su bs tr at e su rf ac e 1 012 , < 1 n /a su rf ac e et ch m ar ks ig en . v es tig ic hn us 27 v. di sc us is p. n ov . r a d tk e et a l. 18 d, e, g 18 d sh al lo w c irc ul ar d ep re ss io ns w ith e tc hm ar ks o f t he m in er al su rf ac e v ar . up to 1 50 n /a 28 v. an nu lu s is p. n ov . r a d tk e et a l. 18 d 18 f, ar ro w s ri ng -s ha pe d et ch m ar ks a ro un d su bs tr at e su rf ac e et ch in g of p os si bl e ep ili th s v ar . up to 1 50 n /a g eologia c roatica 227golubic et al.: ichnotaxonomy of microboring traces in marine aphotic depths traces with serrated outlines form a group that includes transitions between euendolithic microborings in the substrate interior and the etch­marks carved into the external surfaces of carbonate substrates. such substrate surface integration was also recorded for the peripheral filament network of the complex trace saccomorpha papilio isp, nov. etch marks are shallow traces in the host’s shell surface. note the rough surface on the cast of s. papilio isp in fig. 6d. when cast in resin, etched regions tend to remain attached to the resin block following carbonate dissolution and are not dislodged during specimen preparation as are the casts of finer tunnels from the substrate interior. the traces described here as vestigichnus discus igen. nov. isp. nov. represent etch marks that were probably produced by epilithic organisms acting on the substrate surface from the outside, although some, such as v. annulus isp. nov. was observed also to be associated with euendoliths when the latter contacts the substrate surface from within the substrate. 5. conclusions this study presents a photomicrographically­supported review of light­independent euendolithic trace morpho types distributed in holocene and older sediments of the aphotic deep sea zone of modern oceans. a total of seven ichnogenera and twenty­eight ichnospecies were studied. a final list is summarized in the morphometrics table of new and modified ichnotaxa. the value of microboring traces as palaeo­environmental and palaeo­bathymetric indicators depends on the distinction between the traces of phototrophs and organotrophs, thus on information which concerns their biological affiliations, as well as our knowledge about their depth distribution. based on trace morphology alone, this distinction is difficult because of the morphological similarities between light­dependent and light­ independent microboring organisms, caused by convergent evolution due to their similar endolithic mode of life (golubic et al., 2016). both light­dependent and light­independent euendolithic microorganisms evolved adaptations relevant to the structural barriers and constraints posed by the substrate they penetrate. this detailed comprehensive assessment of the deep sea traces, which are all light­independent, was motivated by the need to provide sufficient morphological detail to distinguish them from traces of light­dependent microboring organisms, because only the latter serve in palaeo­bathymetry. we could establish that the excavations by non­clionid microborers of the interior of the bored substrate may be an order of magnitude greater than the damage observed on the substrate surface. this should be verified in future work given the implications for carbon cycling of this discovery. in the present contribution, we have briefly addressed the question of energy and carbon sources of deep sea light­inde­ pendent bioeroders. the observed orientation of euendolithic traces showed that organotrophic microbial euendoliths ex­ ploited the organic matter that the host organisms incorporated when constructing their skeletons (price et al.,1976; song et al., 2019), including proteins that participate in the organi­ zation of carbonate crystallites of the host’s shell (albeck et al., 1993; marin et al., 2005). a few euendolithic taxa might also have been able to exploit organic matter arriving to the benthos via the water column – but boring commenced only after sedimentation onto the benthos. we distinguished between the true euendolithic habit into the interior of the substrate and shallow etchmarks integrated in the substrate surface, as some produced patterns of extremely fine traces, which by comparison with the works of others and our knowledge of modern taxa, may be caused by foraminiferal, thraustochytrids or actinomycete food­collecting systems. boring sponges, some microscopic in size (wisshak, 2008), consume microorganisms that are in suspension. the organo­ trophic euendoliths, in various settings and depths (mao­ che et al., 1996; golubic et al., 2005, 2014; wisshak, 2008), may be indirectly supported by a wide range of primary pro ducers in the oceans, including phototrophy of the phytoplankton (uchman, 2007), and chemolithotrophy in the abyssal seeps and vents (golubic et al., 1984b; reysenbach & cady, 2001; gleason et al., 2017, 2019). the present study is limited by reliance on trace morphology in the sand­sized fraction of the deep sea sediment. hard grounds in the deep sea that have been shown to harbour some unique taxa (smith & demoupolos, 2003), need to be included in future studies with a greater variety of substrates to be examined along depth profiles. knowing the biological identity of traces that reflect the maker’s complete life cycle, can make distinctions among and interpretations of traces more reliable (campbell, 1980). when interpreting traces as ichnotaxa and describing ichnospecies, this work takes the viewpoint that traces are expressions of the behaviour of the organisms that produced them. the nomenclature and classification of traces requires separating the tunnels from the biological identity and classification of trace­making organisms. however, the interpretation of traces requires them to be related to the physiological properties of their biological producers as they behave in modern environments (seilacher, 1967). behaviour is just one of many biological properties of an organism (a member of a biological species), that may change during its growth, development, and physiological state (vegetative vs. reproductive) and produce different traces, documenting instantaneously a permanent change to the substrate it penetrates, leaving holes having sub­micron fidelity that can persist for eons. the microbial boring interactions of trace­makers, their shape and orientation, including features such as anastomosis and avoidance, are indicative of sensing mechanisms that must have a genetic background and control. however, the nature and extent of genetic control of such adaptations remains unknown. the difficulty of finding live deep sea trace­makers in situ and extracting them from the substrate in sufficient quantity to analyze genetically has been a main constraint for the genetic study of all types of endoliths including live ones, in addition to the difficulty of culturing them given their small size and relatively planar presentation. this limitation is only compounded in the oligotrophic deep sea where euendoliths are typically more sparsely settled than in the euphotic zone and no sampling technique of the ultrathin surface layer of newly deposited deep sea sediment is presently g eo lo gi a c ro at ic a 228 geologia croatica 77/3 available for the genetic study of deep sea euendoliths that are likely most active there. our results underline the importance of relating the biological diversity of microboring organisms to the traces they produce using molecular tools that have been available for decades (e.g., woese et al., 1990; amann et al., 1995) and have improved over time (averill et al., 2021). the results obtained from examination of fossil endoliths from deposits in the deep aphotic zones of the world oceans lead us to conclude that the traces can eventually be related to their makers. we also predict that it will be possible to identify many ancient fossil endolithic trace assemblages as well as their modern counterparts as demonstrated in campbell (1980), using careful morphometric analysis that encompasses populations of multiple ichnotaxa as the basis for the assertion that they were deposited in the aphotic depths of ancient seas. acknowledgment we thank the national science foundation for the earliest sup­ port of this work through the national science foundation (nsf) grant ear­8306179 (1980–1982) and nsf grant ear 8107686 (1983–1984) to s. golubic and s.e. campbell, as well as a national aeronautics and space administration (nasa) grant nagw­141 to s. golubic and s.e. camp­ bell. boston university gave a grant to j.e. hook. a us national academy of sciences (nas) eastern european sci­ entist award to s.e. campbell to former yugoslavia supported evaluation of fossil microborings and modern adriatic endo­ lith sample collections in collaboration with k. drobne at the slovenska akademija znanosti in umetnosti (sazu). they examined foraminifera deposited at the benthos. a north at­ lantic treaty organization (nato) postdoctoral fellowship to s.e. campbell to the istituto geologico, univer­ sità di napoli, italy was hosted by bruno d’argenio in 1983, who arranged her visit to his french colleague j. rampal to enhance the study of the mediterranean sea photic and apho­ tic zone endoliths by examining rampal’s extensive collection of foraminifera captured from the open sea water column at controlled depths. the hessisches landesamt für naturschutz, umwelt und geologie provided library and research resources to g. radtke. valuable time on a scanning electron microscope was gen­ erously provided by the museum of comparative zoology at harvard university with the capable assistance of tom seling to s. golubic and s.e. campbell, the univer­ sity of connecticut health centre, farmington ct where con­ nie giles provided the sem technical know­how and exten­ sive access to james e. hook. the woods hole oceanographic institute, the universities of marseille, goettingen, and senck­ enberg museum facilitated by numerous colleagues provided additional sem time, including sus honjo, therese lecampion, and juergen schneider. g. radtke ob­ tained deep sea samples from the red sea. t, sleeter of the bermuda biology station (now known as the bermuda insti­ tute of ocean sciences) provided access in the early 1980’s to deep sea transect samples collected by him in the 1970’s, and lab space to j.e. hook, as did d. belan­santini at the station marine d’endoume and j. rampal, montpellier france to s. e. campbell. professor ruth turner at har­ vard participated in many useful discussions with j.e. hook. boston university retired professors association provided funds for presentations by stjepko golubic of aspects of the research at two international symposia. ellen roosen and kathryn elder assisted james hook with c14 dating by nosams at the woods hole oceanographic institute. ken­ neth nealson of ucla pasadena provided helpful discussion. klaus hoffman critically read several versions of the man­ uscript. we also thank the reviewers and editors who helped ensure a comprehensive literature evaluation and ensured the improved clarity of our interpretation and taxonomic evaluation. the authors have no competing interests to declare that are relevant to the content of this manuscript. references adam, z.r., skidmore m.l., mogk, d.w. & butterfield, n.j. (2017): a laurantian record of the earliest fossil eukaryotes.– geology, 45/5, 387–390. doi: 10.1130/g38749.1 albeck, s., aizenberg, j., addadi, l. & weiner, s. (1993): interac­ tion of various skeletal intracrystalline components with calcite crys­ tals.– journal of the american chemical society, 115, 11691–11697. doi: 10.1021/ja00078a005 al­thukair, a.a. & golubic, s. (1991a): five new hyella species from the arabian gulf.– algological studies, 64, 167–197. al­thukair, a.a. & golubic, s. (1991b): new endolithic cyanobacteria from the arabian gulf. i. hyella immanis sp. nov.– journal of phycology 27, 766–780. doi: 10.1111/j.0022­3646.1991.00766.x al­thukair, a.a., golubic, s. & rosen, g. (1994): new euendolith­ ic cyanobacteria from the bahama bank and the arabian gulf: hyella racemus sp. nov.– journal of phycology, 30, 764–769. doi: 10.1111/j.0022­3646.1994.00764.x amann, r.i., ludwig, w. & schleifer, k.h. (1995): phylogenetic iden­ tification and in situ detection of individual microbial cells without cul­ tivation.– microbiological review 59/1, 143–169. doi: 10.1128/ mr.59.1.143­169.1995 averill, c., werbin, z.e., atherton, k.f., bhatnagar, j.m. & dietze, m.c. (2021): soil microbiome predictability increases with spa­ tial and taxonomic scale.– nature ecology and evolution, 5, 747–756. doi: https://doi.org/10.1038/s41559­021­01445­9 bachmann, e. (1915): kalkoesende algen.– berichte der deutschen bo­ tanischen gesellschaft, 33, 45­57. batters, e.a.l. (1892): on conchocelis, a new genus of perforating algae.– phycological memoirs, 1, 25–28. bathurst, r.g.c. (1966): boring algae, micrite envelopes, and lithification of molluscan biosparites.– journal of geology, 5, 15–32. baucon, a., bordy, e., brustur, t., buatois, l.a., cunning­ ham, t., de, c., duffin, c., felletti, f., gaillard, c., hu, b., hu, l., jensen, s., knaust, d., lockley, m., lowe, p., mayor, a., mayoral, ed., mikulas. r., muttoni, g., de carvalho, c.n. & zhang, w.­t. (2012): a history of ideas in ichnology.– in: bromley, d. & knaust, d. (eds.): trace fossils as indicators of sed­ imentary environments. developments in sedimentology, 64, 3–43. doi: 10.1016/b978­0­444­53813­0.00001­0 beech, i.b. & gaylarde, c.c. (1999): recent advances in the study of biocorrosion: an overview.– revista de microbiologia, 30/3, 177–190. do: 10.1590/s0001­37141999000300001 bengtson, s., sallstedt, t., belivanova, v. & whitehouse, m. (2017) three­dimensional preservation of cellular and subcellular struc­ tures suggests 1.6 billion­year­old crown­group red algae.– plos biol­ ogy, 15/3, e2000735. doi: 10.1371/journal.pbio.2000735 bentis, c.j., kaufman, l. & golubic, s. (2000): endolithic fungi in reef­building corals (order: scleractinia) are common, cosmopolitan, and g eologia c roatica 229golubic et al.: ichnotaxonomy of microboring traces in marine aphotic depths potentially pathogenic.– biological bulletin, 198, 254–260. doi: 10.2307/1542528 bertling, m. (2007): what’s in a name? nomenclature, systematics, ich­ notaxonomy.– in: miller iii, v. (ed.): trace fossils. elsevier, amster­ dam, 81–91. doi: 10.1016/b978­044452949­7/50131­5 bertling, m., braddy, s.j., bromley, r.g., demathieu, r., genise, j., mikuáš, j.k., nielsen, j.k., nielsen, k.s.s, rinds­ berg, k., schlirf, m. & uchman, a. (2006): names for trace fos­ sils: a uniform approach.– lethaia, 39, 265–286. doi: 10.18261/let.55.3.3 bertling, m., buatois, l., knaust, d., laing, b., mángano, m.g., meyer, n., mikuláš, r., minter, n.j., neumann, c., rindsberg, a.k., uchman, a. & wisshak, m. (2022): names for trace fossils 2.0: theory and practice in ichnotaxonomy.–lethaia 55: 1­19. doi: 10.18261/let.55.3.3 boekschoten, g. j. (1966): shell borings of sessile epibiontic organisms as paleoecological guides (with examples from the dutch coast).– pal­ aeogeography, palaeoclimatology, palaeoecology, 2, 333–379. doi: 10.1016/0031­0182(66)90023­x bornet, e. (1891): note sur l’ostracoblabe implexa bornet and flahault.– journal de botanique, 5, 397–400. bornet, e. & flahault, c. (1888): note sur deux noveaux genres d’al­ gues perforantes.–journal de botanique, 2, 161–165. bornet, e. & flahault, c. (1889): sur quelques plantes vivant dans le test calcaire des mollusques.– bulletin de la société botanique de france, 36, 147–179. boudagher­fadel, m.k. & price, g.d. (2010): american miogypsi­ nidae: an analysis of their phylogeny and biostratigraphy.– micropaleon­ tology, 56/6, 567­586 brett, c.e., boucot, a.j. & jones, b. (1993): absolute depths of silu­ r ian benthic assemblages.– lethaia , 26, 25– 40. doi: 10.1111/j.1502­3931.1993.tb01507.x brett, c.e., baird, g.c. & speyer, s.e. (1997): fossil lagerstätten: stratigraphic record of paleontological and taphonomic events.– in: brett, c.e. & baird, g.c. (eds.): paleontological events: stratigraph­ ic paleontological and evolutionary implications. columbia university press, new york, 3­40. bromley, r.g. (1990): trace fossils: biology and taphonomy.– special top­ ics paleontology series. unwin hyman, london, 310 p. bromley, r.g. & nielsen, k.s.s. (2015): bioerosional ichnotaxa and the fossilization barrier.– annales societatis geologorum poloniae, 85, 4453–4455. doi: 10.14241/asgp.2015.033 budd, d.a. & perkins, r.d. (1980): bathymetric zonation and palaeoeco­ logical significance of microborings in puerto rican shelf and slope sed­ iments.– journal of sedimentary petrology, 50, 881–904. doi: 10.1306/212f7b17­2b24­11d7­8648000102c1865d bundschuh, m. (2000): silurische mikrobohrspuren. ihre beschreibung und verteilung in verschiedenen faziesräumen (schweden, litauen, großbritannien und usa).– unpubl. ph.d. thesis, fb geowissenschaf­ ten, j.w.­goethe­universität frankfurt a.m., 129 p. butterfield, n.j. (2015): early evolution of the eukaryote.– palaeontol­ ogy, 58, 5–17. doi: 10.1111/pala.12139 campbell, s.e. (1980): palaeoconchocelis starmachii, a carbonate boring microfossil from the upper silurian of poland (425 million years old): implications for the evolution of the bangiaceae (rhodophyta).– phyco­ logia, 9/1, 25–36. doi: 10.2216/i0031­8884­19­1­25.1 campbell, s.e. (1982a): precambrian endoliths discovered.– nature, 299, 429–431. doi:10.1038/299429a0 campbell, s.e. (1982b): the modern distribution and geological history of calcium carbonate boring microorganisms.– in: westbroek, p. & jong, e.w. (eds.): biomineralization and biological metal accumula­ tion. d. reidel publ. co., dordrecht, 99–104. doi: 10.1007/978­94­009­ 7944­4_8 campbell, s.e. & cole, k. (1984): developmental studies on cultured endolithic conchocelis (rhodophyta).– hydrobiologia, 116, 201–208. doi: 10.1007/bf00027666 campbell, s.e. & hoffman, e.j. (1979): endoliths and their microbor­ ings: how close is the fit?.– 2nd international symposium on fossil al­ gae. abstract with program. campbell, s.e., kazmierczak, j. & golubic, s. (1979): palaeoconchocelis starmachii n. gen, n. sp., a silurian endolithic rhodophyte (ban­ giaceae).– acta palaeontologica polonica, 25, 405–408. campbell, s.e., drobne, k. & cimerman, f. (1983): microborings in foraminiferal tests: an ecological and paleoecological cross­refe­ rence.– rapports et proces­verbaux des reunions commission interna­ tionale pour l’exploration scientifique de la mer méditerranée monaco, 28/3, 245–246. chazottes, v., le campion­alsumard, t. & peyrot­claus­ ade, m. (1995): bioerosion rates on coral reefs: interactions between macroborers, microborers, and grazers (moorea, french polynesia).– pal­ aeogeography, palaeoclimatology, palaeoecology, 113, 189–198. doi: 10.1016/0031­0182(95)00043­l chazottes, v., cabioch, g., golubic, s. & radtke, g. (2009): bathymetric zonation of modern microborers in dead coral substrates from new caledonia – implications for palaeodepth reconstructions in holocene corals.– palaeogeography, palaeoclimatology, palaeoecology, 80, 456–468. doi: 10.1016/j.palaeo.2009.06.033 clements, k.d., german, d.p., piche, j., tribollet, a. & choat, j.h. (2016): integrating ecological roles and trophic diversification on coral reefs: multiple lines of evidence identify parrotfishes as microphag­ es. the linnean society of london.– biological journal of the linnean society, 120, 729–751. doi: 10.1111/bij.12914 couradeau, e., roush, d., scott guida, b. & garcia­pichel, f. (2017): diversity and mineral substrate preference in endolithic micro­ bial communities from marine intertidal outcrops (isla de mona, puerto rico).– biogeosciences, 14, 311–324. doi: 10.5194/bg­2016­254. crimes, t.p. & harper, j.c. (eds.)(1970): trace fossils.– seel house press, liverpool, 547 p. diels, l. (1914): die algenvegetation der südtiroler dolomitriffe.– berichte der deutschen botanischen gesellschaft, 32, 507–531. eckblad, f­e. & kristiansen, g. (1990): ostracoblabe implexa, a tax­ onomic reappraisal.– mycological research, 94, 706–708. doi: 10.1016/ s0953­7562(09)80673­4 ercegović, a. (1925): litofitska vegetacija vapnenaca i dolomita u hrvat­ skoj (la vegetation lithophytes sur les calcaires et les dolomites en cro­ atie).– acta botanica instituti botanici regalis universitatis zagrebien­ sis, 1, 64–114. ercegović, a. (1932): ekološke i sociološke studije o litofitskim cijanofice­ jama sa jugoslavenske obale jadrana (études écologieques et soci­ ologiques des cyanophycées lithophytes de la côte yougoslave del’adriatique).– bulletin international de l’academie yougoslavie des sciences at des arts, 244, 129–220. falkowski, p.g., katz, m.e., knoll, a.h., quigg, a., raven, j.a., schofield, o. & taylor, f.j.r. (2004): the evolution of modern eukaryotic phytoplankton.– science, 305, 354–360. doi: 10.1126/sci­ ence.1095964 färber, c., wisshak, m., pyko, i., bellou, n. & freiwald, a. (2015): effects of water depth, seasonal exposure, and substrate orienta­ tion on microbial bioerosion in the ionian sea (eastern mediterranean).– plos one, 10/4, e0126495. doi: 10.1371/journal.pone.0126495 fine, m. & loya, y. (2002): endolithic algae: an alternative source of pho­ toassimilates during coral bleaching.– proceedings of the royal society, london, 269,1205–1210. doi: 10.1098/rspb.2002.1983 frémy, p. (1930): les myxophycées de l áfrique équatoriale francaise.– ar­ chives de botanique, 2, 1–508. frémy, p. (1934): cyanophyceées des cotes d’europe.– memoires de la so­ ciete nationale des sciences naturelles et mathematiques de cherbourg, 41, 1–234. fremy, p. (1945): contribution à la physiologie des thallophytes marins per­ forant et cariant, des roches calcaires et des coquilles.– annales de l'ins­ titut océanographique, 22, 107–144. frey, r.w. (1975): the study of trace fossils.– springer­verlag, heidelberg. g eo lo gi a c ro at ic a 230 geologia croatica 77/3 friedmann, e.i. (1971): light and scanning electron microscopy of the en­ dolithic desert algal habitat.– phycologia, 10, 411–428. garcia­pichel, f., ramirez­reinat, e. & gao, q. (2010): micro­ bial excavation of solid carbonates powered by p­type atpase­mediated transcellular ca2+ transport.– proceedings of the national academy of sciences usa, 107, 21749–21754. doi: 10.1073/pnas.1011884108 garraffoni, a. r. s. & freitas, a.v.c. (2017): photos belong in the taxonomic code.­ science, 355, 6327. doi: 10.1126/science.aam7686 gerdes, g., claes, m., dunajtschik­piewak, k., riege, h., krumbein, w. & reineck, h.­e. (1993): contribution of microbial mats to sedimentary surface structures.–facies, 29, 61–74. doi: 10.1007/ bf02536918 glaub, i. (1994): mikrobohrspuren in ausgewählten ablagerungsräumen der europäischen jura und der unterkreide (klassifikation und palöko­ logie).– courier forschungs institut senckenberg, 174, 292 p. glaub, i., golubic, s., gektidis, m., radtke, g. & vogel, k. (2007): microborings and microbial endoliths: geological implications.– in: miller, w. (ed.): trace fossils: concepts, problems, prospects. el­ sevier, amsterdam, 368–381. doi: 10.1016/b978­044452949­7/50147­9 gleason, f.h., gadd, g.m., pitt, j.i. & larkum, a.w.d. (2017): the roles of endolithic fungi in bioerosion and disease in marine ecosystems. i. general concepts. mycology. 1–11. (published online). ii. potential facultatively parasitic anamorphic ascomycetes can cause disease in cor­ a l s and mol luscs .– mycolog y, 8/3, 216 –227. doi: 10.1080/21501203.2017.1352049 gleason, f.h., larkum, a.w.d., raven, j.a., manohar, c.s. & lilje, o. (2019): ecological implications of recently discovered and poorly studied sources of energy for the growth of true fungi especially in extreme environments.– fungal ecology, 39, 380–387. doi: 10.1016/j. funeco.2018.12.011 golubic, s. (1969): distribution, taxonomy, and boring patterns of marine endolithic algae.–american zoologist, 9, 747–751. golubic, s. (1990): shell boring microorganisms.– in: boucot, a. (ed.): the evolutionary paleobiology of behavior and coevolution. elsevier, amsterdam, 347–352. golubic, s. & knoll, a.h. (1993): fossil prokaryotes.– in: lipps, j.h. (ed.): fossil prokaryotes and protists. blackwell, 51–76. golubic, s. & schneider, j. (2003): microbial endoliths as internal bio­ films.– in: krumbein, w.e, dornieden, t. & volkmann, m. (eds.): fossil and recent biofilms. kluwer academic publishers, dordtre­ cht, 249–263. golubic, s., brent, g. & le campion, t. (1970): scanning electron microscopy of endolithic algae and fungi using a multipurpose casting­ embedding technique.– lethaia, 3, 203–209. golubic, s., perkins, r.d. & lukas, k.j. (1975): boring microorgan­ isms and microborings in carbonate substrates.– in: frey r.w. (ed.): the study of trace fossils. springer­verlag, heidelberg, 229–259. golubic, s., friedmann, i. & schneider, j. (1981): the lithobiontic ecological niche, with special reference to microorganisms.– journal of sedimentary petrology, 51, 475–478. golubic, s., campbell, s.e. & spaeth, c. (1983): kunsharzausgüsse fossiler mikroben­bohrgänge (resin­casting of fossil microbial bor­ ings).– der präparator, bochum, 29, 197–200. golubic, s., campbell, s.e., drobne, k., cameron, b., balsam, w.l., cimerman, f. & dubois, l. (1984a): microbial endoliths: a benthic overprint in the sedimentary record, and a paleobathymetric cross­reference with foraminifera.– journal of paleontology, 58, 351–361. golubic, s., hook, j.e., sikes, e. & curray, j. (1984b): biological communities at the florida escarpment resemble hydrothermal vent taxa.– science, 226, 965–967. doi: 10.1126/science.226.4677.965 golubic, s., radtke, g. & le campion­alsumard, t. (2005): en­ dolithic fungi in marine ecosystems.– trends in microbiology, 13, 229– 235. doi: 10.1016/j.tim.2005.03.007 golubic, s., radtke, g. & le campion­alsumard, t. (2007): en­ dolithic fungi.– in: ganguli, b.n. & deshmukh, s.k. (eds.): fun­ gi: multifaceted microbes. anamaya publishers, new delhi, 38­48. golubic, s., radtke, g., campbell, s.e., lee s.­j., vogel, k. & wisshak, m. (2014): the complex fungal microboring trace saccomorpha stereodiktyon isp. nov. reveals growth strategy of its maker.– ichnos, 21, 100–110. doi: 10.1080/10420940.2014.888301 golubic, s., pietrini, a.m. & ricci, s. (2015): euendolithic activity of the cyanobacterium chroococcus lithophilus erc. in biodeterioration of the pyramid of caius cestius, rome, italy.– international biodeteriora­ tion and biodegradation, 100, 7–16. doi: 10.1016/j.ibiod.2015.01.019 golubic, s., campbell, s.e., lee s­j. & radtke, g. (2016): depth distribution and convergent evolution of microboring organisms.– paläontologische zeitschrift, 90/2, 315­326. doi: 10.1007/s12542­016­ 0308­6 golubic, s., schneider, j., le campion­alsumard, t., camp­ bell, s.e., hook, j.e. & radtke, g. (2019): approaching micro­ bial bioerosion.– facies, 65, 1–18. doi: 10.1007/s10347­019­0568­1 grange, j.s., rybarczyk, h. & tribollet, a. (2015): the three steps of the carbonate biogenic dissolution process by microborers in coral reefs (new caledonia).– environmental science pollution research, 22,13625–13637. doi:10.1007/s11356­014­4069­z green, j.w., knoll, a.h. & swett, k. (1988): microfossils from oolites and pisolites of the upper proterozoic eleonore bay group, central east greenland.– journal of paleontology, 62, 835–852. doi: 10.1017/ s0022336000030109 guida, b.s. & garcia­pichel, f. (2016): extreme cellular adaptations and cell differentiation required by a cyanobacterium for carbonate ex­ cavations.– proceedings of national academy of science usa, 113/2, 5712–5717. doi: 10.1073/pnas.1524687113 hamilton, w.a. (2003) microbially influenced corrosion as a model sys­ tem for the study of metal microbe interactions: a unifying electron trans­ fe r hy p o t h e s i s . – b iofo u l i n g , 19 /1, 65 –76 . d o i : 10.1080/0892701021000041078 hassenrück, c., jantzen, c., försterra, g., häussermann, v. & willenz, p. (2013): rates of apical septal extension of desmophyllum dianthus: effect of association with endolithic photo­auto­ trophs.– marine biology, 160, 2919–2927. doi.: 10.1007/ s00227­013­2281 höhnk, w. (1969): űber den pilzlichen befall kalkiger hartteile von mee­ restieren.– deutsche wissenschaftliche komission für meeresforschung, hamburg, 20/2, 129–140. hofmann, k. (1996) die mikro­endolithischen spurenfossilien der borea­ len oberkreide nordwest­europas.– geologisches jahrbuch a, 136, 1­153. hook, j.e. (1991): microborings from the deep atlantic (bermuda pedestal; blake plateau) and gulf of mexico (florida escarpment): borers and the ecological and diagenetic fate of the microborings.– unpubl. ph.d. the­ sis. boston university graduate school, 207 p. hook, j.e. & golubic, s. (1988): mussel periostracum from deep­sea re­ dox communities as a microbial habitat: the scalloping periostracum bor­ er.– pubblicazioni della stazione zoologica di napoli i: marine ecology, 9, 347–364. doi: 10.1111/j.1439­0485.1988.tb00212.x hook, j.e. & golubic, s. (1990): mussel periostracum from deep­sea re­ dox communities as a microbial habitat 2: pit borers.– pubblicazioni del­ la stazione zoologica di napoli i: marine ecology, 11, 239–254. doi: 10.1111/j.1439­0485.1990.tb00242.x hook, j.e. & golubic, s. (1992): mussel periostracum from deep­sea re­ dox communities as a microbial habitat 3: secondary inhabitants.– pub­ blicazioni della stazione zoologica di napoli i: marine ecology, 13, 119–131. doi: 10.1111/j.1439­0485.1992.tb00344.x hook, j.e. & golubic, s. (1993): microbial shell destruction in deep­sea mussels, florida escarpment.– pubblicazioni della stazione zoologica di napoli i: marine ecology, 14, 81–89. doi: 10.1111/j.1439­0485.1993. tb00366.x hook, j.e., golubic, s. & milliman, j.d. (1984): micritic cement in microborings is not necessarily a shallow­water indicator.– journal of sedimentary petrology, 54, 425–431. doi: 10.1306/212f8431­2b24­11d7­ 8648000102c1865d international commission on zoological nomencla­ ture (iczn)(1999): international code of zoological nomenclature. g eologia c roatica 231golubic et al.: ichnotaxonomy of microboring traces in marine aphotic depths fourth edition.– international trust for zoological nomenclature, lon­ don, 306 p. doi: 10.5962/bhl.title.50608 javaux, e.j. & knoll, a.h. (2016): micropaleontology of the lower mes­ oproterozoic roper group, australia, and implications for early eukary­ otic evolution.– journal of paleontology, 91/2, 99–229. doi: 10.1017/ jpa.2016.124 kazmierczak, j. & golubic, s. (1976): oldest organic remains of bor­ ing algae from polish upper silurian.– nature, 261, 404–406. knoll, a.h., green, j.w., golubic, s. & swett, k. (1986): peritidal assemblages from the late proterozoic limestone­dolomite series, cen­ tral east greenland.– geological society of america, annual meeting 1986, abstracts and program, 17, 631. knoll, a.h. & golubic, s. (1992): proterozoic and living cyanobacteria.– in: schidlowski m., golubic, s., kimberley, m.m, mc­ kirdy, d.m & trudinger, p.a. (eds.): early organic evolution, implications for mineral and energy resources. springer­verlag, berlin, 450–462. kobayashi, i. & samata, t. (2006): bivalve shell structure and organic matrix.– materials science and engineering, 26/4, 692–698. doi.: 10.1016/j.msec.2005.09.101 kohlmeyer, j. (1969): the role of marine fungi in the penetration of ca­ lcareous substances.– american zoologist, 9, 741–746. kołodziej, b., golubic, s., bucur, i.i., radtke, g. & tribollet, a. (2012): early cretaceous record of microboring organisms in skele­ tons of g rowing corals.– lethaia , 45, 34 – 45. doi: 10.1111/j.1502­3931.2011.00291.x krause, s., liebetrau, v., nehrke, g., damm, t., büsse, s., lei­ pe, t., vogts, a., gorb, s.n. & eisenhauer, a. (2019): endolit­ hic algae affect modern coral carbonate morphology and chemistry.– frontiers of earth science, 7, 304. doi: 10.3389/feart.2019.00304 krumbein, w.e. (2010): gunflint chert microbiota revisited – neither stro­ matolites, nor cyanobacteria.– in: seckbach, j. & oren, a. (eds.): microbial mats. cellular origin, life in extreme habitats and astrobi­ ology, vol 14. springer, dordrecht. doi: 10.1007/978­90­481­3799­2_4 krumbein, w.e., paterson, d.m. & zavarzin, g.a. (eds)(2003): fos­ sil and recent biofilms: a natural history of life on earth.– kluwer academic publishers, dordrecht. doi: 10.1007/978­94­017­0193­8 kühl, m. & revsbech, n.p. (2001): biogeochemical sensors for bound­ ary layer studies.– in: boudreau, b.p. & jørgensen, b.b (eds.): the benthic boundary layer, 189–210. doi: 10.1093/ oso/9780195118810.003.0008 kühl, m., fenchel, t. & kazmierczak, j. (2003): growth, structure and calcification potential of an artificial cyanobacterial mat.– in: krumbein, w.e., paterson, d.m. & zavarzin, g.a. (eds) (2003): fossil and recent biofilms: a natural history of life on earth,. kluwer academic publishers, dordrecht 77–102. doi: 10.1007/978­94­ 017­0193­8_5 le campion­alsumard, t. (1969): contribution sur l’étude des cyano­ phycées lithophytes des étages supralittoral et médiolittoral (région de marseille).– tethys, 1, 119–171. le campion­alsumard, t., campbell, s.e. & golubic, s. (1982): endoliths and the depth of the photic zone; discussion.– journal of sedi­ mentary petrology, 52, 1333–1334. doi: 10.1306/212f8134­2b24­11d7­ 8648000102c1865d le campion­alsumard, t., golubic, s. & hutchings, p. (1995a): microbial endoliths in skeletons of live and dead corals: porites lobata (moorea, french polynesia).– marine ecology progress series, 117, 149– 157. doi: 10.3354/meps117149 le campion­alsumard, t., golubic, s. & priess, k. (1995b): fun­ gi in corals: symbiosis or disease? interaction between polyps and fungi causes pearl­like skeleton biomineralization.– marine ecology progress series, 117, 137–147. doi: 10.3354/meps117137 loron, c.c., francois, c., rainbird, r.h., turner, e.c., boren­ sztain, s. & javaux, e.j. (2019a): early fungi from the proterozoic era in arctic canada.– nature, 570, 232–235. doi: 10.1038/s41586­019­ 1217­0 loron, c.c, rainbird, r.h., turner, e.c., wilder greenman, j. & javaux, e.j. (2019b): organic­walled microfossils from the late mesoproterozoic to early neoproterozoic lower shaler supergroup (arc­ tic canada): diversity and biostratigraphic significance.– precambrian research, 321, 349–374. doi: 10.1016/j.precamres.2018.12.024 lukas, k.j. (1974): two species of the chlorophyte genus ostreobium from skeleton of atlantic and caribbean reef corals.– journal of phycology, 10, 331–336. doi: 10.1111/j.1529­8817.1974.tb02722.x lukas, k.j. (1978): depth distribution and form among common microbor­ ing algae from the florida continental shelf.– geological society of america. annual meeting 1978, abstracts and program, 10, 448. mao­che, l., le campion­alsumard, t., boury­esnault, n., payri, c., golubic, s. & bezac, c. (1996): biodegradation of shells of the black pearl oyster pinctada margaritifera var. cumingii, by micro­ borers and sponges of french polynesia.– marine biology, 126, 509–519. doi: 10.1007/bf00354633 marin, f. & luquet, g. (2004): molluscan shell proteins.– comptes ren­ dus palevol, 3, 469–492. doi : 10.1016/j.crpv.2004.07.009 marin, f., amons, r., guichard, n., stigter, m., hecker, a., luquet, g., layrolle, p., alcaraz, g., riondet, c. & west­ broek, p. (2005): caspartin and calprismin, two proteins of the shell calcitic prisme of the mediterranean fan mussel pinna nobilis.– journal of biological chemistry, 280/40, 33895–33908. doi: 10.1074/jbc. m506526200 marin, f., luquet, g., marie, b. & medakovic, d. (2007): mollus­ can shell proteins: primary structure, origin, and evolution.– current topics in developmental biology, 80, 209–276. doi: 10.1016/s0070­ 2153(07)80006­8 massé, a, tribollet, a., meziane, t., bourguet‐kondracki, m.l., yéprémian, c., sève, c., thiney, n., longeon, a., co­ uté, a. & domart‐coulon, i. (2020): functional diversity of mi­ croboring ostreobium algae isolated from corals.– environmental mi­ crobiology, 22/1, 4825–4846. doi.: 10.1111/1462­2920.15256 may, j.a. & perkins, r.d. (1979): endolithic infestation of carbonate sub­ strates below the sediment­water interface.– journal of sedimentary pe­ t rology, 49, 357–378. doi: 10.1306/212f7748­2b24­11d7­ 8648000102c1865d meyer, n., wisshak, m. & freiwald, a. (2020): ichnodiversity and bathymetric range of microbioerosion traces in polar barnacles of sval­ bard.– polar research, 39. doi: 10.33265/polar.v39.3766 miller iii, w. (2007a): complex trace fossils.– in: miller iii, w. (ed.): trace fossils: concepts, problems, prospects,. elsevier, amsterdam 458–465. doi: 10.1016/b978­044452949­7/50153­4 miller iii, w. (ed.)(2007b): trace fossils: concepts, problems, prospects.– elsevier, amsterdam, 632 p. miura, a. (1961): a new species of porphyra and its conchocelis­phase in nature.– journal of the tokyo university fisheries, 47, 305–311. murray, j.w. (1973): distribution and ecology of living benthic foraminif­ erids.– heinemann, london,. 274 p. murray, j.w. (1991): ecology and palaeoecology of benthic foraminifera.– logman scientific & technical, london, 408 p. nadson, g.a. (1900): die perforierenden (kalkbohrenden) algen und ihre bedeutung in der natur.– scripta botanica horti universitatis petropo­ lis,18, 1–40. nadson, g.a. (1927): les algues perforantes de la mer noire.– comptes rendus l’académie des science, 184, 896. neumann, c. (1966): observations on coastal erosion in bermuda and me­ asurements of the boring rate of the sponge, cliona lampa.– limnology and oceanography, 11, 92–108. palinska, k.a., abed, r.m.m., vogt, j.c., radtke, g. & golubic, s. (2017): microbial endoliths adriatic limestone coast: morphological vs. molecular diversity.– geomicrobiology, 34, 903–915. doi: 10.1080/01490451.2017.1297512 paull, c.k., hecker, b., commeau, r., freeman­lynde, r.p., neumann, c., corso,w.p., golubic, s., hook, j.e., sikes, e. & curray, j. (1984): biological communities at the florida escarpment g eo lo gi a c ro at ic a 232 geologia croatica 77/3 resemble hydrothermal vent taxa.– science, 226, 965–967. doi: 10.1126/ science.226.4677.965. pernice, m., raina, j­b., rädecker, n., cárdenas, a., pogore­ utz, c. & voolstra, c.r. (2020): down to the bone: the role of over­ looked endolithic microbiomes in reef coral health.– international society for microbial ecology journal, 14/2, 325–334. doi: 10.1038/s41396­019­ 0548­z pica, d., tribollet, a., golubic, s., bo, m., gioia di camillo, c., bavestrello, g. & puce, s. (2016): microboring organisms in living stylasterid corals (cnidaria, hydrozoa).– marine biology resear­ ch, 12/6, 573–582. doi: 10.1080/17451000.2016.1169298 plotnick, r.e. (2012): behavioral biology of trace fossils.– paleobiology, 38/3, 459–473. doi: 10.1666/11008.1 porter, c.l. & zebrowski, g. (1937): lime­loving molds from austral­ ian sands.– mycologia, 29, 252–257. poulicek, m. & jaspar versali, m.f. (1984): biodegradation de la trame organique des coquilles de mollusques en milieu marin: action des microorganismes endoliths.– société royale des sciences de liège, bul­ letin, 53, 114–126. price, t.j., thayer, g.w., lacroix, m.w. & montgomery, g.p. (1976): the organic content of shells and soft tissues of selected estuarine gastropods and pelecypods.– proceedings of national shellfish associa­ tion, 65, 26–31. priess, k., le campion­alsumard, t., golubic, s., gadel, f. & tomassin, b.a. (2000): fungi in corals: black bands and density­band­ ing of porites lutea and p. lobata skeleton.– marine biology, 136, 19–27. doi: 10.1007/s002270050003 radtke, g. (1991): die mikroendolitischen spurenfossilien im alt­tertiär west­europas und ihre palökologische bedeutung.– courier forschun­ gsinstitut senckenberg, 138, 1–185. radtke, g. (1992): microendolithic trace fossils of paris basin as facies in­ dicators.– proceeding 7th international coral reef symposium, 1, 419– 426. radtke, g. (1993): the distribution of microborings in molluscan shells from recent reef environments at lee stocking island, bahamas.– fa­ cies, 29, 81–92. doi: 10.1007/bf02536921 radtke, g. & golubic, s. (2005): microborings in mollusk shells, bay of safaga, egypt: morphometry and ichnology.– facies, 51, 118–134. doi: 10.1007/s10347­005­0016­02 radtke, g. & golubic, s. (2011): microbial euendolithic assemblages and microborings in intertidal and shallow marine habitats: insights in cyanobacterial speciation.– in: reitner, j., queric, w. & arp, g. (eds.): advances in stromatolite geobiology – lecture notes in earth sciences, 131, 213–244. springer, berlin. doi: 10.1007/978­3­ 642­10415­ 2_16 radtke, g., le campion­alsumard, t. & golubic, s. (1996): mi­ crobial assemblages of the bioerosional "notch" along tropical limestone coasts.– algological studies, 83, 469–482. doi: 10.1127/algol_ stud/83/1996/469 radtke, g., hofmann, k. & golubic, s. (1997): a bibliographic over­ view of micro­ and macroscopic bioerosion.– courier forschungsinstitut senckenberg, 201, 307–340 radtke, g., glaub, i., vogel, k. & golubic, s. (2010): a new di­ chotomous microboring: abeliella bellafurca isp. nov., distribution, var­ iability and biological origin.– ichnos, 17, 25–33. doi: 10.1080/10420940903358628 radtke, g., schäfer, p., blaschke, h. & golubic, s. (2011): mi­ croborings from shallow marine habitats on both sides of the panama isthmus.– annale des naturhistorischen museums, wien, series a, 113, 245–265. https://www.semanticscholar.org/paper/microborings radtke, g., campbell, s.e. & golubic, s. (2016): conchocelichnus seilacheri igen. and isp. nov., a complex microboring trace of bangialean rhodophytes.– ichnos, 23/3–4, 228–236. doi.: 10.1080/10420940. 2016.1199428 reid, r.p., foster, j.s., radtke, g. & golubic, s. (2011): modern marinestromatolites of little darby island, exuma archipelago, baha­ mas: environmental setting, accretion mechanisms and role of euendo­ liths. in: reitner, j., queric, w. & arp, g. (eds.): advances in stromatolite geobiology – lecture notes in earth sciences, 131, 77­89. springer, berlin. doi: 10.1007/978­3­642­10415­2_4 reysenbach, a­l. & cady, s.l. (2001): microbiology of ancient and modern hydrothermal systems.– trends in microbiology, 9, 79–86. doi: 10.1016/s0966­842x(00)01921­1 rioult, m. & dangeard, l. (1967): importance des cryptogames perfo­ rantes marines en geologie.– le botaniste, 50, 389–413. roush, l. & garcia­pichel, f. (2020): succession and colonization dy­ namics of endolithic phototrophs within intertidal carbonates.–microor­ ganisms, 2020, 8/2, 214. doi: 10.3390/microorganisms8020214 samata, t., hayashi, n., kono, m., hasegawa, k., horita, c. & akera, s. (1999): a new matrix protein family related to the nacreous layer formation of pinctada fucata.–federation of european biochemi­ cal society letters, 462, 225–229. doi: 10.1016/s0014­5793(99)01387­3 sanchez­baracaldo, p., raven, j., pisani, d. & knoll, a. (2017): early photosynthetic eukaryotes inhabited low salinity habitats.– pro­ ceedings of the national academy of sciences usa, 114, e7737­e7745. doi: 10.1073/pnas.1620089114 sarashina, i. & endo, k. (2001): the complete primary structure of mol­ luscan shell protein 1 (msp­1), an acidic glycoprotein in the shell matrix of the scallop patinopecten yessoensis.– marine biotechnology, 3, 362– 369. doi: 10.1007/s10126­001­0013­6 schauer, r., bienhold, c., ramette, a. & harder, j. (2010): bac­ terial diversity and biogeography in deep­sea surface sediments of the south atlantic ocean.– the international society for microbial ecology journal, 4, 159–170. doi: 10.1038/ismej.2009.106 schmidt, m. (1990): mikrobohrspuren in fossilien der triassischen hall­ stätter kalke und ihre bathymetrische bedeutung.– facies, 23, 109–119. doi: 10.1007/bf02536709 schneider j. (1976): biological and inorganic factors in the destruction of limestone coasts.– contributions to sedimentology, 6, 1–112. schneider, j. & le campion­alsumard, t. (1999): construction and destruction of carbonates by marine and freshwater cyanobacteria.– euro­ pean journal of phycology, 34, 417–426. doi: 10.1080/09670269910001736472 schneider, j. & torunski, h. (1983): biokarst on limestone coasts, mor­ phogenesis and sediment production.– marine ecology, 4, 45–63. schönberg, c.h.l. (2008): a history of sponge erosion: from past myths and hypotheses to recent approaches.– in: wisshak, m. & tapani­ la, l. (eds.): current developments in bioerosion, 165–202. springer­ verlag, new york. doi: 10.1007/978­3­540­77598­0_9 schönberg, c.l, gleason, f.h., meyer, n. & wisshak, m. (2019): close encounters in the substrate: when macroborers meet microborers.– facies 65,25. doi: 10.1007/s10347­019­0567­2 schopf, j.w. & klein c. (eds.)(1992): the proterozoic biosphere: a mul­ tidisciplinary study.– cambridge university press, 1374 p. doi: 10.1017/ cbo9780511601064 seilacher, a. (1967): fossil behavior.– scientific american, 217, 72–80. seilacher, a. (2007): trace fossil analysis.– springer­verlag, new york, 226 p. smith, c.r. & demoupolos, a.w.j. (2003): ecology of the pacific ocean floor.– in: tyler, p.a. (ed.): ecosystems of the world, 179–218. else­ vier, amsterdam. song, x., liu, z., wang, l. & & song l. (2019): recent advances of shell matrix proteins and cellular orchestration in marine molluscan shell bi­ omineralization.– frontiers in marine science, 10. https://doi.org/10.3389/ fmars.2019.00041 spero, h.j. (1988): ultrastructural examination of chamber morphogenesis and biomineralization in the planktonic foraminifer orbulina universa.– marine biology, 99, 9–20. doi: 10.1007/bf00644972 swinchatt, j.p. (1969): algal boring: a possible depth indicator in carbo­ nate rocks and sediments.– geological society of america, bulletin, 80, 1391–1396. g eologia c roatica 233golubic et al.: ichnotaxonomy of microboring traces in marine aphotic depths tribollet, a. (2008a): dissolution of dead corals by euendolithic micro­ organisms across the northern great barrier reef (australia).– microbial ecology, 55/4, 569–580. doi: 10.1007/s00248­007­9302­6 tribollet, a. (2008b): the boring microflora in modern coral reef ecosystems: a review of its roles.– in: wisshak, m. & tapanila, l. (eds.): current developments in bioerosion. springer­verlag, new york, 67–94. doi: 10.1007/978­3­540­77598­0_4 tribollet, a. & golubic, s. (2005): cross­shelf differences in the pattern and pace of bioerosion of experimental carbonate substrates exposed for 3 years on the northern great barrier reef, australia.– coral reefs, 24, 422–434. doi: 10.1007/s00338­005­0003­7 tribollet, a., golubic, s., radtke, g. & reitner, j. (2011a): on microbiocorrosion.– in: reitner, j., queric, w. & arp, g. (eds.): advances in stromatolite geobiology – lecture notes in earth sciences, 131, 265­276. springer, berlin. tribollet, a., radtke, g. & golubic, s. (2011b): bioerosion.– in: reitner, j. & thiel, v. (eds.): encyclopedia of geobiology. lecture notes in earth sciences series, 117–134. springer­verlag, new york. doi: 10.1007/978­1­4020­9212­1_25 tribollet, a., chauvin, a. & cuet, p. (2019): carbonate dissolution by reef microbial borers: a biogeochemical process producing alkalinity under different pco2 conditions.– facies, 65, 9. doi: 10.1007/s10347­018­ 0548­x tseng, c.k. & chang, t.j. (1955): studies on porphyra iii, sexual repro­ duction of porphyra.– acta botanica sinica, 4, 153–166. uchman, a. (2007): deep­sea ichnology: development of major concepts.– in: miller iii, w. (ed.): trace fossils: concepts, problems, prospects. elsevier, amsterdam, 248­267. doi: 10.1080/09853111.2015.1065306 valliappan, k., sun, w. & li., z. (2014): marine actinobacteria associa­ ted with marine organisms and their potentials in producing pharmace­ utical natural products.– applied microbiology and biotechnoogy, 98, 7365–7377. doi: 10.1007/s00253­014­5954­6 vallon, l.h., rindsberg, a.k. & bromley, r.g. (2016): an updated classification of animal behavior preserved in substrates.– geodinamica acta, 28, 5–20. doi: 10.1080/09853111.2015.1065306 vogel, k. & brett, c.e. (2009): record of microendoliths in different fa­ cies of the upper ordovician in the cincinnati arch region usa: the early history of light­related microendolithic zonation.– palaeogeogra­ phy, palaeoclimatology, palaeoecology, 281, 1–24. doi: 10.1016/j.pal­ aeo.2009.06.032 vogel, k., golubic, s. & brett, c.e. (1987): endolith associations and their relation to facies distribution in the middle devonian of new york state, usa.– lethaia, 20, 263–290. doi: 10.1111/j.1502­3931.1987. tb02047.x vogel, k., gektidis, m., golubic, s., kiene, w.e. & radtke, g. (2000): experimental studies on microbial bioerosion at lee stoking is­ land, bahamas and one tree island, great barrier reef, australia: im­ plications for paleoecological reconstructions.– lethaia, 33, 190–204. doi: 10.1080/00241160025100053 walker, m., johnsen, s., rasmussen, s.o., popp, t., steffensen, j.­p., gibbard, p., hoek, w., lowe, j., andrews, j., björk, s., cwynar, l.c., hughen, k., kershaw, p., kromer, b., litt, t., lowe, d.j., nakagawa, t., newnham, r. & schwander, j. (2009): formal definition and dating of the gssp (global stratotype section and point) for the base of the holocene using the greenland ngrip ice core, and selected auxiliary records.­ journal of quaternary science 24, 3–17. https://doi.org/10.1002/jqs.1227 wierzchos, j., casero, m.c., artieda, o. & ascaso, c. (2018): en­ dolithic microbial habitats as refuges for life in polyextreme environment of the atakama desert.– current opinion in microbiology, 43, 124–139. doi: 10.1016/j.mib.2018.01.003 wisshak, m. (2006): high­latitude bioerosion: the kosterfjord experi­ ment.– lecture notes in earth sciences, 109, 1–202. springer, heidel­ berg. doi: 10.1007/978­3­540­36849­6. wisshak, m. (2008): two new dwarf entobia ichnospecies in a diverse aph­ otic ichnocoenosis (pleistocene / rhodes, greece).– in: wisshak, m. & tapanila, l. (eds.): current developments in bioerosion. springer­ verlag, heidelberg, 213–233. doi: 10.1007/978­3­540­77598­0_11 wisshak, m. (2012): microbioerosion. in: bromley, d. & knaust, d. (eds.): trace fossils as indicators of sedimentary environments,. devel­ opments in sedimentology, 64, 213–243. elsevier, amsterdam. doi: 10.1016/b978­0­444­53813­0.00008­3 wisshak, m. (2019): taming an ichnotaxonomical pandora’s box: revision dendritic and rosette microborings (ichnofamily: dendrinidae).– euro­ pean journal of taxonomy, 390, 1–99. doi: 10.5852/ejt.2017.390 wisshak, m. & neumann, c. (2018): large dendrinids meet giant clam: the bioerosion trace fossil neodendrina carnelia igen. et isp. n. in a tridacna shell from pleistocene­holocene coral reef deposits, red sea, egypt.– fossil record, 21, 1–9. doi: 10.5194/fr­21­1­2018 wisshak, m. & porter, d. (2006): the new ichnogenus flagrichnus – a paleoenvironmental indicator for cold­water settings?.– ichnos, 13/3, 135–145. doi: 10.1080/10420940600851255 wisshak, m. & rüggeberg, a. (2006): colonisation and bioerosion of experimental substrates by benthic foraminiferans from euphotic to aph­ otic depths (kosterfjord, sw sweden).– facies, 52, 1–17. doi: 10.1007/ s10347­005­0033­1 wisshak, m. & tapanila, l. (eds.)(2008): current developments in bi­ oerosion.– springer­verlag, berlin, 516 p. doi: 10.1007/978­3­540­77598­ 0_11 wisshak, m., gektidis, m., freiwald, a. & lundälv, t. (2005): bioerosion along a bathymetric gradient in a cold­temperate setting (kosterfjord, sw sweden): an experimental study.– facies, 51, 93–117. doi: 10.1007/s10347­005­0009­1 wisshak, m., tribollet, a., golubic, s., jakobsen, j. & fre­ iwald, a. (2011): temperate bioerosion: ichnodiversity and biodiver­ sity from intertidal to bathyal depths (azores).– geobiology, 9, 492–520. doi: 10.1111/j.1472­4669.2011.00299.x wisshak, m., alexandrakis, e. & hoppenrath, m. (2014a): the diatom attachment scar ophthalmichnus lyolithon igen. et isp. n.– ichnos, 21, 111–118. doi: 10.1080/10420940.2014.907572 wisshak, m., schönberg, c.h.l., form, a. & freiwald, a. (2014b): sponge bioerosion accelerated by ocean acidification across spe­ cies and latitudes?.– helgoland marine research, 68, 253–262. doi: 10.1007/s10152­014­0385­4 wisshak, m., meyer, n., radtke, g. & golubic, s. (2018): saccomorpha guttulata, a new marine fungal microbioerosion trace fossil from cool­ to cold­water settings.–paläontologische zeitschrift, 92, 3, 525– 533. doi: 10.1007/s12542­018­0407­7 wisshak, m., knaust, d. & bertling, m. (2019): bioerosion ichno­ taxa: review and annotated list.– facies, 65, 24. doi: 10.1007/s10347­019­ 0561­8 woese, c.r., kandler, o. & wheelis, m.l. (1990): towards a natural system of organisms: proposal for the domains archaea, bacteria, and eucarya.– proceedings of national academy of sciences usa, 87, 4576– 4579. doi: 10.1073/pnas.87.12.4576 zebrowski, g. (1936): new genera of cladochytriaceae.– annals of the missouri botanical garden, 23, 553–564. zeff, n.l. & perkins, r.d. (1979): microbial alteration of bahamian deep­ sea carbonates.– sedimentology, 26, 175–201. doi: 10.1111/j.1365­ 3091.1979.tb00350.x zhang, y. & golubic, s. (1987): endolithic microfossils (cyanophyta) from early proterozoic stromatolites, hebei, china.– acta micropalaeon­ tologica sinica, 4, 1–12. zhang, x­g & pratt, b.r. (2008): microborings in early cambrian phosphatic and phosphatized fossils.– palaeogeography, palaeoclimato­ logy, palaeoecology, 267, 185–195. doi: 10.1016/j.palaeo.2008.06.015 2021 | 74/3 | 225–235 | 7 figs. | 3 tabs. | 1 suppl. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction drilling predation is one of the most studied biotic interactions in the fossil record, and papers dealing with this topic have been extensively published since the 1960s (see klompmaker et al., 2019 and references therein). information retrieved from the fossil traces, in this case preserved as drill holes, provide insight into the predator-prey relationship and other aspects of palaeoecology. according to klompmaker et al. (2019, fig. 2), the majority of the research papers on drilling predation refer to molluscs; the majority of predation evidence occurs as a drill hole, with predominantly molluscs being both prey and predator. fossil and extant gastropod families recorded as predators include the capulidae (parasitic), cassidae, eulimidae (parasitic), marginellidae, muricidae, nassariidae and naticidae (e.g., carriker, 1981; kabat, 1990; złotnik, 2001; klompmaker et al., 2019 and references therein). the most studied shell drilling preda tors among them are the naticids and muricids. while there are many papers dealing with predatory drillings on recent mollusc (bivalves and gastropods) shells, only a few of them document such behaviour in the middle miocene (badenian) of the central paratethys (e.g., hoffmann et al., 1974; görög & somody, 1988; kowalewski, 1990; hoffmeister & kowalewski, 2001; złotnik, 2001; sawyer & zuschin, 2011; ganić et al., 2016). in the aforementioned predation studies on the middle miocene molluscs from central paratethys, there are no data from croatia. here, we report for the first time drilling analysis on the middle miocene gastropods from croatia, on the south-western margin of the central paratethys. middle miocene serial killers: drilled gastropods from the south-western margin of the central paratethys, croatia marija bošnjak,1 jasenka sremac,2 bojan karaica,3 ivan mađerić,4 and anja jarić5 1 croatian natural history museum, demetrova 1, 10 000 zagreb, croatia; (marija.bosnjak@hpm.hr) 2 university of zagreb, faculty of science, department of geology, horvatovac 102a, 10 000 zagreb, croatia 3 the ministry of economy and sustainable development, radnička cesta 80, 10 000 zagreb, croatia 4 prudic 22, 10 291 zdenci brdovečki, croatia 5 tratinska 57, 10 000 zagreb, croatia doi: 10.4154/gc.2021.19 abstract this paper focuses on traces of drilling predation in the middle miocene gastropod assemblage of the zaprešić brijeg locality, croatia, which provides further insight into the palaeoecology of the south-western margin of the pannonian basin system during the badenian. the analyzed gastropod shells were collected in the first half of the 20th century, and are housed in the croatian natural history museum (cnhm) in zagreb. the cnhm zaprešić brijeg collections contain 11063 gastropod shells, of which 1024 have been identified as drilled (9.3% of the sample), with 633 successfully drilled, 113 unsuccessfully drilled, and 278 multiply drilled shells. the most represented families are potamididae, nassariidae, clavatulidae, turritellidae, cerithiidae, muricidae and naticidae. the gastropod families naticidae and muricidae are recognized as the probable predators based on the shape of the drill holes. middle miocene (badenian) gastropods drilling frequency at zaprešić brijeg is 5.72%, which is lower than the recorded badenian gastropods drilling frequency in the central paratethys, while the overall gastropod prey effectiveness from the studied locality (15.15%) is higher than the average of the neighbouring badenian localities in the central paratethys. among the most represented gastropods at this locality, the highest drilling frequency occurs in the infaunal suspension feeders turritellidae (14.45%), which mostly show traces of the naticid drilling. the croatian natural history museum (cnhm) in zagreb hosts a large collection of the middle miocene (badenian) marine gastropods from the zaprešić brijeg locality near samobor, 30 km west of zagreb, croatia (fig. 1), where many of the shells have predation marks in the form of drill holes. the zaprešić brijeg fossils (gastropods and bivalves) were originally collected at the beginning of the 20th century from the highly fossiliferous „light yellow sandstones“ outcropping in local vineyards of zaprešić brijeg (also known as zaprešić breg, zaprešićki vinogradi or vrhovčak). bulk sampling was organized by the curator of the samobor museum, stjepan orešković, and performed by the local residents (e.g., pavlovsky, 1957). the collection was later housed in the cnhm. our objective was to count drilling frequencies in the za pre šić brijeg material, and to compare them to the available data from the middle miocene (badenian) of the central paratethys (e.g., görög & somody, 1988; hoffmeister & kowalewski, 2001; sawyer & zuschin, 2011; ganić et al., 2016) (fig. 2). in this study the focus is on: (1) the frequencies of the drill holes present on the gastropods; and (2) their probable predator(s). 2. geological setting the zaprešić brijeg locality lies west of the centre of samobor, and 2 km south-east of the village of dubrava, towards the village of vrhovčak, around 30 km from zagreb (fig. 1). this area is part of the rift-type north croatian basin (ncb), located in the south-western part of the pannonian basin system (pbs) surrounded by the alps, carpathians and dinarides (e.g., pavelić & kovačić, 2018) (fig. 2). palaeogeographically it article history: manuscript received december 17, 2020 revised manuscript accepted august 25, 2021 available online october 20, 2021 keywords: drilling predation, naticidae, muricidae, badenian, croatia, central paratethys g eo lo gi a c ro at ic a geologia croatica 74/3226 belonged to the south-western margin of the central paratethys (e.g., rögl, 1998; pavelić, 2001; harzhauser & piller, 2007; kováč et al., 2007, 2017, 2018; piller et al., 2007; pavelić & kovačić, 2018). marine connections between the central paratethys and the neighbouring marine areas were repeatedly opened and closed during the miocene, controlling the deposition (rögl, 1998; pavelić, 2001; harzhauser & piller, 2007; kováč et al., 2007, 2017, 2018; piller et al., 2007; pavelić & kovačić, 2018). miocene marine transgressions did not cover the entire croatian part of the pannonian basin system simultaneously, and the basement is therefore unconformably overlain by neogene deposits of various ages (e.g., pavelić & kovačić 2018 and references therein). the presented zaprešić brijeg locality is part of the samoborsko gorje mt. (fig. 1). the neogene basement of the samoborsko gorje mt. is diverse and most commonly composed of triassic dolomites (gorjanović-kramberger, 1894; šuklje, 1929), with, at some localities a volcanogenic-sedimentary complex of cretaceous age, and less often a palaeogene clastic-carbonate complex (šikić k. et al., 1978, 1979; vrsaljko et al., 2005 and references therein). the oldest miocene sediments are badenian (langhian) deposits overlying triassic dolomites. vrsaljko et al. (2005) describe algal shallow-water limestones as the most common lithotype at the beginning of the transgression. they are overlain by silty marls. bakrač et al. (2010) recognized two badenian marine transgressive-regressive cycles (tb 2.4 and tb 2.5) in deposits of the neighbouring vrhovčak section. the late badenian marine transgressive-regressive cycle tb 2.5 could be a consequence of a short, but intense marine transgression due to eustatic sea level rise with the opening of the connection between the central paratethys and the indo-pacific ocean (vrsaljko et al., 2005; kováč et al., 2007; bartol et al., 2014). history of the zaprešić brijeg locality investigations the geology of the zaprešić brijeg locality was first described by gorjanović-kramberger (1894). the basement of the neogene sediments is composed of triassic dolomites, and the roof sediments are defined as the “leithakalk”. below the “leithakalk”, white and light yellow sandstones occur containing a large amount of mollusc shells and other fossils. gorjanović-kramberger (1894, 1896) collected and determined the fossil fauna (foraminifera, molluscs, balanids, fish and mammals), and assumed that these neogene sediments belonged to figure 1. geographical position of the zaprešić brijeg locality, between the villages of dubrava and vrhovčak, west of samobor (after google earth, december, 2020). figure 2. palaeogeography of the central paratethys during the badenian, ~ 14 ma (after sant et al. 2019, fig. 6a) with marked locations of the study area (1) and comparison localities (2 after ganić et al., 2016, 3 after sawyer & zuschin, 2011, and 4 after görög & somody, 1988). sketch of localities in austria and slovakia in the upper right corner after sawyer & zuschin (2011, fig. 2) (marked with red asterisks). the blue colour denotes marine areas of normal salinity based on the present-day outcrops; violet denotes regions with no outcrop data for the given time period; ? marks an uncertain area of palaeoconnection through the slovenian strait (after sant et al., 2019, fig. 6a). g eologia c roatica bošnjak et al.: middle miocene serial killers: drilled gastropods from the south-western margin of the central paratethys, croatia 227 the „mediterranean age“ (= badenian), and compared them with the grund formation near vienna, which he considered to be contemporaneous with the zaprešić brijeg sediments based on the fossil fauna and distribution of the gastropod pereiraea gervaisi (vézian, 1856) (previously pereiraia gervaisi) in croatia, slovenia and hungary. the grund formation belongs to the middle miocene – langhian, that is, in the central paratethys chronostratigraphy, the badenian (e.g., harzhauser et al., 2003, ćorić et al., 2004). the collected fauna also contains a freshwater species, vitta picta (férussac, 1823) (old name neritina picta férussac, 1823), which was probably brought into the marine sediments by river flows. šuklje (1929) pointed out that the most abundant fossils at zaprešić brijeg are gastropods, with the genera pleurotoma and cerithium as the most numerous, and confirmed the conclusions of gorjanović-kramberger (1894, 1896). pavlovsky (1957, 1960) continued the determinations of the zaprešić brijeg gastropods, and assigned the stratigraphic age of the locality to the middle miocene – langhian / lower badenian (in original: „lower tortonian“), comparing it to the “grund” layers. bajraktarević (1978), based on the zaprešić brijeg foraminifera, concluded that the age of the sediment is middle miocene – serravalian / upper badenian (in the original: „upper tortonian“ (ammonia (= rotalia) beccarii zone)). based on the presence of the genera cerithium, pirenella and nassa in the zaprešić brijeg assemblage, vrsaljko (1990) interpreted the palaeoenvironment as shallow marine with sporadic brackish and freshwater areas. mađerić (2017) described naticid and muricid drillings from zaprešić brijeg within his bsc thesis, based on gastropods housed at the faculty of science, university of zagreb. the age of the zaprešić brijeg horizons is still not precisely determined. we visited the area several times, in the hope of finding the fossiliferous horizon and conducting further research, but these deposits are no longer available at the surface due to the expansion of settlements, plantations and vineyards. however, due to the presence of the marine gastropod species pereiraea gervaisi (vézian, 1856) in the assemblage, the age could be further restricted to the upper part of the middle badenian or to the upper badenian (upper langhian – serravallian), close to the nn5 nn6 nannozone boundary (bartol et al., 2014; mikuž & šoster, 2014). 3. materials and methods analyses of the drilled gastropod shells from zaprešić brijeg were made on 11063 specimens from the cnhm collections, inventory numbers 1419-1544, and 10305-10414 (table 1, supplement 1). the analyzed fauna was taxonomically categorized into families according to the world register of marine species (worms). revision of the gastropod fauna in the collection is beyond the scope of this work. this material comprises representatives of marine (44), marine and brackish (2), and brackish (2) families. four families live as infauna (naticidae, turritellidae, aporrhaidae and nassariidae), while the other families live as epifauna. looking at the feeding type of the gastropods, they are categorized into four groups: carnivores, suspension feeders, detritivores and grazers. two families from freshwater and terrestrial environments were excluded from the analyses due to their non-marine origin. the first step was to distinguish the drilled from non-drilled gastropod shells. we counted the shells with one and more drillings visible, and based on that, the shells were divided into two groups, drilled and non-drilled gastropod shells. drilled gastrotable 1. analyzed gastropod families from the cnhm collection with drilling predation data. abbreviations: n = number of specimens; dhs = successfully drilled shells; udhs = unsuccessfully drilled shells; df (%) = drilling frequency; pe (%) = prey effectiveness. family n dhs udhs df (%) pe (%) 11063 633 113 5.72 15.15 trochidae 1 0 0 0 0 pisaniidae 1 0 0 0 0 neritidae 32 0 0 0 0 melanopsidae 2 0 0 0 0 pachychilidae 11 0 0 0 0 cerithiidae 508 65 15 12.8 18.75 litiopidae 1 0 0 0 0 scalioidae 1 0 0 0 0 potamididae 4459 201 36 4.51 15.19 turritellidae 1253 181 28 14.45 13.4 rissoidae 3 0 0 0 0 seguenziidae 2 0 0 0 0 zebinidae 1 0 0 0 0 strombidae 8 0 0 0 0 aporrhaidae 13 1 1 7.69 50 calyptraeidae 14 0 0 0 0 naticidae 90 5 4 5.56 44.44 triviidae 1 0 0 0 0 eratoidae 6 0 0 0 0 cassidae 2 0 0 0 0 charoniidae 6 0 0 0 0 epitoniidae 1 0 0 0 0 eulimidae 1 0 0 0 0 muricidae 150 10 2 6.67 16.67 tudiclidae 17 1 0 5.88 0 babyloniidae 1 0 0 0 0 buccinidae 2 1 0 50 0 nassariidae 2428 34 4 1.4 10.53 columbellidae 11 0 0 0 0 melongenidae 11 1 0 9.09 0 fasciolariidae 5 0 0 11.11 0 volutidae 18 0 1 0 100 mitridae 3 0 0 0 0 costellariidae 8 0 0 0 0 olividae 1 0 0 0 0 ancillaridae 70 2 2 2.86 50 cancellariidae 14 2 0 14.29 0 conidae 12 0 0 0 0 borsoniidae 18 1 0 5.56 0 drillidae 13 3 1 23.08 25 clavatulidae 1813 122 17 6.73 12.23 turridae 10 2 1 20 33.33 terebridae 4 1 1 25 50 pyramidellidae 1 0 0 0 0 acteonidae 15 0 0 0 0 ringiculidae 15 0 0 0 0 cylichnidae 5 0 0 0 0 retusidae 1 0 0 0 0 g eo lo gi a c ro at ic a geologia croatica 74/3228 pod shells were further categorized as (a) successfully drilled shells (dhs), (b) unsuccessfully drilled shells (udhs), and (c) multiply drilled shells (mult-dhs) (supplement 1). a successfully drilled gastropod shell has one complete drill hole with one entrance in the shell (figs. 3a, 3b, 3c, 3d), and an unsuccessfully drilled shell (figs. 3e, 3f) has one incomplete drill hole with only the outer layer of the shell drilled, and no entrance hole. multiply drilled shells have more than one successful and/or unsuccessful drill holes (figs. 3g, 3h, 3i, 3j), showing the traces of predator drillings and parasitic holes on the shell. in this study we focused on the successfully drilled shells (dhs) and unsuccessfully drilled shells (udhs) showing the predator drillings made by gastropods, not taking into consideration multiply drilled shells and their agents. analysis of predation intensity was determined as drilling frequency (df) (lower taxon frequency (ltf) according to kowalewski, 2002), which aims to estimate the frequency of interactions for a given taxon of prey (here family) measuring the rate of prey mortality due to the drilling predation (e.g., kelley & hansen, 1993; kowalewski, 2002; sawyer & zuschin, 2011; ganić et al., 2016; pahari et al., 2016; sarkar et al., 2016): df (ltf) = dk / nk, where k is a lower taxon target (here family), dk is the number of specimens of that taxon that contain one successful predation trace (drill hole) and nk is the total number of specimens of that taxon in the sample (after kowalewski, 2002). in the text we use the term drilling frequency (df) for the ltf (lower taxon frequency). the estimate that provides some measure of the predator’s failure is called the escalation parameter (kowalewski, 2002). the relative frequency of failed attacks is often referred to as „prey effectiveness“, which documents traces of unsuccessful attacks (e.g., repair scar or healed drill hole) as described in kowaleski (2002): pe = tf / tt, where pe is prey effectiveness computed as tf, the number of a particular trace fossil of predatory origin that records failed attacks (e.g., the number of incomplete and healed drill holes) divided by tt, the total number of these trace fossils (e.g., the total number of drill holes) (e.g., kowalewski, 2002; sawyer & zuschin, 2011; hutchings & herbert, 2013; ganić et al., 2016; pahari et al., 2016; sarkar et al., 2016). to indicate a probable predator, we categorized drill holes as made by naticid, muricid or an undeterminable agent, following the descriptions in e.g., hoffmann et al., 1974; carriker, 1981; kabat, 1990; kowalewski, 2002, 2004. naticid drillings are parabolic (straight or oblique) and the drill hole is countersunk (outer drill hole diameter is larger than the inner diameter). muricid drillings are cylindrical, with nearly straight edges. abbreviations used in the figures and tables in the following sections are as follows (alphabetically): df (%) = drilling frequency; dh = drill hole; dhs = successfully drilled shells; mult-dh = multiple drill holes; multdhs = multiply drilled shells; n = number of specimens in the sample; pe (%) = prey effectiveness; udhs = unsuccessfully drilled shells. 4. results among the 11063 analysed middle miocene (badenian) gastropod shells from the zaprešić brijeg locality from the cnhm, 1024 shells were drilled (dhs, udhs and mult-dhs), among which 746 shells belong to dhs and udhs, 6.7% of the studied sample (supplement 1). the distribution of these categories is shown in fig. 4. within the drilled sample (9.3% of the total), 61.8% exhibit one complete drill hole. the most numerous families exhibiting drillings in the sample are the potamididae (4459 specimens), nassariidae (2428 specimens), clavatulidae (1813 specimens), turritellidae (1253 specimens), cerithiidae (508 specimens), muricidae (150 specifigure 3. examples of drilled shells in the analyzed sample. a-d) successfully drilled shells. e-f) unsuccessfully drilled shells. g-j) multiply drilled shells. scale bar: 5 mm. a, i, j: inv. no. 10.403. clavatula (clavatula) granulatocincta (münster in goldfuss, 1840); b: inv. no. 10.374. cerithium (thericium) turonicum (mayer, 1878); d, g, h: inv. no. 10.379. turritella (eichwaldiella) bicarinata bicarinata eichwald, 1830; c, e, f: inv. no. 1425. natica (nacca) millepunctata tigrina (defrance, 1825). figure 4. distribution of the drilled shells categories. g eologia c roatica bošnjak et al.: middle miocene serial killers: drilled gastropods from the south-western margin of the central paratethys, croatia 229 mens), and naticidae (90 specimens) (fig. 5, supplement 2). the potamididae have the highest number of the successfully drilled shells (201), followed by the turritellidae (181), clavatulidae (122), cerithiidae (65), and other families (fig. 5a, supplement 2). potamididae live in the marine and brackish environments as epifauna. others (clavatulidae and cerithiidae) live in marine environments as epifauna, and the turritellidae are a marine semi-infauna (supplement 1). figure 5b. shows the distribution of the unsuccessfully drilled shells, again with the potamididae family showing the highest number of unsuccessfully drilled shells (36) as well as the highest number of specimens. the number of unsuccessfully drilled shells is relatively small compared to the successfully drilled shells (fig. 5a). other families are represented with less than 30 undrilled shells (supplements 1 and 2). the average rate of prey mortality due to the drilling predation (df) for the whole analyzed gastropod sample is 5.72% (table 1, supplement 1). when we look at the drilling frequencies of the most numerous families in the sample (supplement 2), df ranges from 1.4% (nassariidae) to 14.45% (turritellidae). figure 5. the most numerous gastropod families exhibiting drillings. a) successfully drilled shells. b) unsuccessfully drilled shells. c) multiply drilled shells. data in supplements 1 and 2. g eo lo gi a c ro at ic a geologia croatica 74/3230 relative frequency of failed attacks (pe) for the analyzed sample is 15.15% (table 1, supplement 1). looking at the numerously represented families in the sample (supplement 2), pe ranges from 10.53% (nassariidae) to 44.44% (naticidae). drilling differences between infauna and epifauna in the ana lyzed sample are shown in supplements 3 and 4. the average df of the infauna (5.84%) is slightly higher than the df of the epifauna (5.66%), while the average pe of the infauna (14.34%) is lower than the pe of the epifauna (15.57%) indicating that the infauna is less successful at resisting the drilling attack. this result may be affected by the biased preservation of epifaunal gastropod shells, while epifaunal shells are less resistant to various taphonomic processes. categorization of the gastropods based on their feeding type and drilling occurence is shown in supplement 5. most gastropods represented in the sample are grazers (5029 specimens). the highest df is observed in the suspension feeders (14.29%), represented mostly by turritellids, and the lowest among the carnivores (3.89%). the highest pe occurs within the detritivores (50%), and the lowest within suspension feeders (13.4%). to analyze which prey predators prefer, we looked at the shape of the drill holes and categorized them as naticid drill holes, muricid drill holes and undeterminable, where the attacker is uncertain (fig. 6, supplements 6 and 7). fig. 6a shows the distribution of the categorized drill holes in the sample within the most represented families with successfully drilled gastropod shells. as shown in fig. 6a, naticid drillings prevail, especially on the shells of the turritellidae. examination of the unsuccessfully drilled shells (fig. 6b), shows that the attacks are mostly undeterminable, and, if they are determinable, they are categorized as naticid drillings, with the majority of the prey belonging to the turritellidae. 5. discussion analyses of drilling predation can offer insight into the palaeoecology of fossil molluscs (e.g., kowalewski, 2002). available published papers on drilling predation describing the central paratethys miocene molluscs as prey and predators, geographically cover the present day area of poland, bulgaria, hungary, austria, slovakia and serbia (table 2 and references therein). figure 6. distribution of potential predators based on the drill hole shape of the most represented families in the sample. a) successfully drilled shells. b) unsuccessfully drilled shells. data shown in supplements 6 and 7. table 2. drilling predation recorded from the central paratethys gastropod assemblages. paper studied area age or epoch (in paper) predation hofmann et al. (1974) korytnica clays, poland “lower tortonian” (= lower badenian) muricid and naticid predation on molluscs (gastropods, bivalves, scaphopods) kowalewski (1990) korytnica clays, poland middle miocene quantitative paleoecological analysis of predation by shell drilling gastropods złotnik (2001) korytnica clays, poland middle miocene naticid predation on molluscs (bivalves, gastropods) kojumdgieva (1974) in kabat (1990) bulgaria middle miocene naticid and muricid predation on gastropods görög & somody (1988) hungary badenian predation on gastropods dávid (1993, 1999) wind brickyard, hungary late oligocene / egerian naticid predation on molluscs (bivalves, gastropods, scaphopods) sawyer & zuschin (2011) austria and slovakia karpatian and badenian drilling predation on molluscs (bivalves, gastropods, scaphopods) zagyvai & demeter (2008) waldhof, austria early sarmatian gastropods prey-predatory interaction ganić et al. (2016) rakovica sand, serbia badenian molluscs (bivalves, gastropods) drillings g eologia c roatica bošnjak et al.: middle miocene serial killers: drilled gastropods from the south-western margin of the central paratethys, croatia 231 comparison between the miocene marine deposits of europe (boreal and paratethys provinces – from the present areas of austria, slovakia and hungary) was analyzed by hoffmeister & kowalewski (2001), giving the spatial patterns on predation on the burdigalian and langhian molluscs. the authors conclude that numerous studies on predator-prey relationship are based on local palaeoecological interpretations and/or long-term temporal trends. since predation data can significantly vary from one locality or province to another due to the spatial variation in predation, hoffmeister & kowalewski (2001) suggest that analyses should concentrate more toward documenting spatial variation in predation analyzing multiple sites (e.g., sawyer & zuschin, 2011). in this presented predation analysis, it was not possible to include more sites into the palaeoecological study (as well as in e.g., ganić et al., 2016). in the published studies on the central paratethys badenian gastropod predation so far, data from croatia are missing. in the following section we describe and compare drilling predation on gastropods from the zaprešić brijeg locality with the available data obtained from the other trace fossil studies on the badenian gastropods from the central paratethys (görög & somody, 1988; sawyer & zuschin, 2011, and ganić et al., 2016). 5.1. gastropod drilling predation in the central paratethys during the badenian drilling predation studies on the middle miocene (badenian) gastropods from the central paratethys have been made on the collections from hungary (görög & somody, 1988) and bulk samples from the vienna basin (austria and slovakia, in sawyer & zuschin, 2011) and serbia (ganić et al., 2016). görög & somody (1988) describe drilling and settlement traces on badenian gastropods from the sand pit at várpalota in hungary. the várpalota fauna (further in the text we refer to it as v-h), with 6620 specimens (after table 1 in görög & somody, 1988) is dominated by the herbivorous gastropod families potamididae and turritellidae. the main predators are the naticids and muricids. sawyer & zuschin (2011) analyze drilling predation on molluscan assemblages from the lower and middle miocene (upper burdigalian/karpatian, langhian-lower serravallian/badenian) localities in austria and slovakia (vienna basin; further in the text we refer to it as vb). the bulk sample consists of 39234 mollusc shells (bivalves, gastropods, scaphopods and polyplacophorans), and the most numerous are gastropods (22292 specimens, of which 9101 are the badenian gastropods). the authors consider the muricids and naticids as the most likely predators. mollusc predation from the southern part of the central paratethys is described in ganić et al. (2016), on the middle miocene (badenian) bulk sample from the rakovi ca stream sands near belgrade (further in the text we refer to it as rsb-s). authors analyze 2301 shells of molluscs (gastropods and bivalves; 1617 gastropod specimens) drillings, and conclude that carnivorous gastropods are dominant in the sample and the main predators were muricids and naticids. in supplement 8. we show the abundance comparison between badenian gastropods from the zaprešić brijeg locality (further in the text is refered to as zbl-c), with part of the recorded badenian gastropods from v-h and rsb-s, based on both published and data presented herein for gastropods present in all three localities. the abundance from vb is not shown because that study includes both karpatian and badenian localities, with given abundance for only part of the gastropods represented in the badenian deposits. the most numerous gastropods in zbl-c and v-h belong to the potamididae, with the most abundant number of specimens belonging to the genera pirenella and terebralia (supplement 8), while in rsb-s the potamidids are not recorded. the nassariidae and turritellidae families are also abundant at the zbl-c and v-h localities, and are present in the rsb-s. among the turritellids the most numerous is the genus turritella, and from the nassariidae, the genus nassarius is the most abundant at the zbl-c, dorsanum at v-h, and nassa at rsb-s. when we compare the distribution of the gastropod predators, naticids and muricids, naticids prevail at v-h and rsb-s (genus natica), while in zbl-c prevail muricids (genus ocinebrina). the most likely predators at all the described localities, including the vb, are the naticidae and muricidae. it should be noted that when we compare the present fossil fauna, differences could be possible due to the gastropods classification. for example, in some cases one genus belongs to one family in one register, and in another register it is assigned to the other family. the numerical ratio of complete analyzed gastropod samples from the above described central paratethys localities is shown in figure 7. as presented in sawyer & zuschin (2011, table 3), mollusc drilling frequency (df) for the karpatian (upper burdigalian) and badenian (langhian and lower serravalian) of the central paratethys is 7.5%, which is lower in comparison with the neighbouring miocene areas of the boreal province (24.5%) and the entire paratethys (14%) (hoffmeister & kowalewski, 2001). the badenian gastropods of vb display a df of 9.2%. the df of the rsb-s gastropods is a similar value, 9.65%. in contrast, df in the zbl-c gastropods is significantly lower: 5.72% (table 3). there are no data for the df and pe for the v-h fauna, only the list and number of damaged specimens (see table 1 and 2 in görög & somody, 1988). results for the pe again differ between the compared areas. the pe of the vb badenian gastropods at 2.2% (sawyer & zuschin, 2011, fig. 6b) is lower than the pe of zbl-c which equals 15.15%, and the pe of 7.18% of the rsb-s gastropods (table 3). similarities between the df and pe of the most drilled gastropod shells between zbl-c, vb and rsb-s are shown in table 3. comparing the drillings of the most represented gastropods from the zbl-c, with the neighbouring badenian areas in the paratethys, the highest df in the marginal area of the central paratethys is in the turritellidae (14.45%, present paper, and 17.33% in rsb-s). cerithiidae also have a higher df value in the marginal areas of the central paratethys (12.8% in present paper, and 14.41% in rsb-s). the predator gastropods, naticidae and figure 7. ratio of gastropod numbers between the compared localities. legend: 1 = rsb-s after ganić et al. (2016); 2 = v-h after görög & somody (1988); 3 = vb after sawyer & zuschin (2011); 4 = this paper. g eo lo gi a c ro at ic a geologia croatica 74/3232 muricidae, have lower df values in the marginal central paratethys areas, than the average of the central paratethys (table 3). the families with the higher df values in the marginal area have lower values than the central paratethys values based on the results from the localities in austria and slovakia, and vice versa. comparison of the pe shown in table 3, indicates that the badenian gastropods from the central paratethys marginal areas have higher pe than the average of central paratethys. the highest pe in the marginal area have naticidae (44.44% in present study, and 25% in rsb-s). as shown in sawyer & zuschin (2011), dfs could fluctuate within similar environments at a single locality. it should be mentioned that comparison on drilling predation between the zbl-c (this paper), vb and rsb-s is based on uneven gastropod abundances (see figure 7). the number of specimens within families greatly differ at the mentioned study areas. also, sawyer & zuschin (2011) made an analyses on multiple sites, and ganić et al. (2016) and this paper only on one locality. differences in values between naticids and muricids (predator gastropods) could also be the consequence of a smaller amount of predator naticids in marginal areas (90 specimens zbl-c; 49 specimens in rsb-s) than in the central paratethys average (403 specimens in vb). 5.2. probable predators of zaprešić brijeg gastropods muricids and naticids are the most likely gastropod predators in the zaprešić brijeg. both groups use a highly specialized accessory boring organ (abo) which aids the drilling process chemically by secreting an acid which affects prey shell layers by dissolving them and excavates a hole through which the prey tissue is extracted (e.g., carriker, 1981; kabat, 1990). however, the families differ in their habitat and how they attack (predation style). muricids live as epifauna and attack mostly epifauna. muricoidea in general feed on bivalves, barnacles, gastropods, small crabs, encrusting bryozoans, fish carrion, and may be cannibals (e.g., carriker, 1981 and references therein) as well as herbivores, but the majority of muricids are shell drillers primarily interested in gastropods (e.g., kabat, 1990). also, muricids attack in groups, so the multiple muricid drilling could be a consequence of group hunt (e.g., hoffmann et al., 1974). on the other hand, naticids live as infauna and attack mostly infaunal organisms. they prey on gastropods, bivalves, scaphopods, ostracods, with infaunal gastropods and bivalves as their primary prey (e.g., kabat, 1990). however, they can also attack on the surface (e.g., hoffman et al., 1974; pahari et al., 2016). naticids do not attack in groups. as described in kabat (1990), the sequence of prey capture events by extant naticid includes detection of the prey, evaluation, seizure, covering and immobilization of the prey, wrapping in the dilated foot of the naticid, dragging for some distance and covering into sand for commencement of boring. as naticids enfold the prey with their foot and look for the boring place, multiple naticid drillings on one shell could be the consequence of the prolonged time of boring or the fact that naticids do not recognize if the prey is alive or dead and they drill shells which are already drilled (e.g., hoffmann et al., 1974). it is possible that naticids just produce multiple drill holes during a single attack (e.g., kabat, 1990), or as described in görög & somody (1988) the double borings may have been produced by two predators or by one which needed more space to extract the food. our assumption here is that the predator drilling was fatal to the prey, and shells having one successful drill hole can possibly support this, although a possibility remains that the prey could escape the predator (kowalewski, 1990, 2004). unsuccessfully drilled shells with regenerated drillings (repair scar on the shell) and/or incomplete drillings can be a sign of an unfinished attack from a predator (e.g., chattopadhyay & baumiller, 2007, 2010; hutchings & herbert 2013). other potential drillers, except muricidae and naticidae, could be the gastropods marginellidae, capulidae, nassariidae, and cassidae, as well as cephalopods, who are all capable of drilling holes in the shells (e.g., kabat, 1990; złotnik, 2001; klompmaker et al., 2019). marginellidae are not present in the analyzed sample, so we can discard them as other potential drillers at the studied site. capulidae are ectoparasitic symbionts of molluscs and echinoderms, with cylindrical drill holes similar to muricid drilling and leave an attachment scar on the host shell (kabat, 1990). capulidae are not present in the analyzed sample either, and an attachment scar in the surrounding area of the drill hole is not recorded, so we can also discard them. nassariidae (2428 specimens) are mobile scavengers and predators, but in the recent nassariids the drill hole diameter is not larger than 0.25 mm, and drillers are mostly juvenile nassariids (złotnik, 2001). however, we can exclude nassariids due to the fact that they are mostly herbivores or scavengers, in addition to the fact that the studied drillings do not correspond to nassariid drill hole measurements (e.g., kabat, 1990; kowalewski, 1990; złotnik, 2001). cassidae (2 specimens) mostly drill echinoid tests (e.g., kabat, 1990), and rarely bivalve shells (kabat, 1990; złotnik, 2001), so they are not the potential drillers here. cephalopods (octopuses) are shell boring predators of molluscs, with drillings of an irregular or oval outline and extremely small inner drill hole diameter (e.g. kabat, 1990). we have recorded smaller and larger drill hole diameters in the analyzed sample, but the drillings were circular so we dismiss cephalopods as possible predators here. the highest df from the zaprešić brijeg occurs in the fami ly turritellidae, with naticid drill holes as the most abundant drillings (fig. 6a, 6b, supplements 6 and 7). in the successfully drilled shells there are drill holes that look like muricid drillings, as well as undeterminable drill holes (fig. 6a). in the unsuccessfully drilled shells, the drillings are recognized as naticid or undeterminable (fig. 6b). looking at the analyses of the presented gastropod sample, the other naticid choices of prey were mostly potamidids, clavatulids and cerithiids (fig. 6a), although these table 3. comparison of drilling frequency and prey effectiveness in total and on the most drilled gastropod families between the zaprešić brijeg locality (a, this paper), the central paratethys (b, after sawyer & zuschin, 2011, fig. 6), and the belgrade area at the south-eastern margin of the central paratethys (c, after ganić et al., 2016). symbols: / = no available data; * = karpatian and badenian; – = without pe. family df (%) pe (%) a b c a b c potamididae 4.51 12.5 / 15.19 0.8 / turritellidae 14.45 7.1 17.33 13.4 0 7.14 clavatulidae 6.73 / 0 12.23 / – cerithiidae 12.8 7.6* 14.41 18.75 2.5* 10.53 nassariidae 1.4 8.5 5.03 10.53 4.4 0 muricidae 6.67 9.6* 0 16.67 9.1* – naticidae 5.56 8.3 6.12 44.44 0 25 total (all specimens) 5.72 9.2 9.65 15.15 2.2 7.18 g eologia c roatica bošnjak et al.: middle miocene serial killers: drilled gastropods from the south-western margin of the central paratethys, croatia 233 three families live as epifauna, and the naticids are characterized as predators of infaunal organisms. however, it was noted that muricids also attacked shallow-burrowing bivalves in more offshore habitats, explained by the hypothesis of atypical feeding behaviour, residual nature of the fossil assemblage, smaller fossilization potential of the epifauna, and misidentification of naticid drillings for muricid ones (kowalewski, 1990). most of the drill holes in the unsuccessfully drilled shells belong again to three epifaunal families (potamidids, clavatulids and cerithiids), beside turritellids, and most of the drillings are undeterminable in origin, except the majority of drillings on turritellids (fig. 6b). as shown in fig. 6, there are more naticid drillings in the sample than the muricid ones, although the number of naticids in the sample (90) is smaller than the muricids (150). although muricids attack more epifaunal organisms and gastropods, this sample is characterized by most of the drillings being either of naticid or undeterminable origin. possible reasons for the prevalence of naticids over muricid drillings are: (1) originally there were more naticids in the sample – due to the taphonomic processes they were not present at the locality because of their fragile shells that are more easily carried away in suspension than the muricid shells; (2) a possible rapid burial event – living as infauna, naticids find more easily their way to the surface than the muricids who are epifauna; and (3) mistaking muricid drillings for the naticids, and vice versa, and not recognizing the undeterminable drillings. other organisms that can produce naticidand muricidlike drill holes include nematodes, flatworms, octopods and other gastropods (kowalewski, 2004). at the neighbouring v-h locality görög & somody (1988) give an analyses of the naticid and muricid borings. although the muricidae are less abundant in the sample, their drillings prevail, with most drillings on potamididae (see table 2 in görög & somody, 1988). naticid drillings prevail on the turritellidae and nassariidae, which is in accordance with the predators mode of life. distinguishing naticid from muricid drilling solely on morphological criteria can be difficult because the drilling mechanisms are similar (złotnik, 2001). transitions from naticidto muricidtype of drilling have been noticed (hoffmann et al., 1974), and also, the same species can drill holes in different shapes (kowalewski, 2004). therefore the determination of the drill hole shape in our sample should be considered as only a probable indication of predator identity, especially given the great number of drill holes categorized as undeterminable (fig. 6). 5.3. comparison with the recent assemblages most of the recent research papers dealing with the origin of drillings in gastropod shells are based on laboratory experiments, and focused mostly on predator behaviour (e.g., chattopadhyay & baumiller, 2007; casey & chattopadhyay, 2008, chattopadhyay et al., 2014). złotnik (2001 and references therein) mentioned that the laboratory enduced behaviour (e.g., by starvation) differs from nassariid drilling behaviour in nature. in the samples collected from the northern adriatic sea, turritellids were the most commonly drilled (sawyer & zuschin, 2010). they were mostly drilled by naticids, but since they live buried directly under the sediment surface, they are more susceptible to both muricid and naticid drillers (sawyer & zuschin, 2010 and references therein), as it is also noted in our sample (fig. 6, supplements 6 and 7), and e.g., tull & böhning-gaese (1993). allmon (2011) described the ecology of the turritellidae, pointing out that recent turritellids are mainly sessile semi-infaunal suspension feeders living in shallow waters of full-marine salinity and temperatures below 20°c, but also occur as an active group which can crawl on the surface and thrive at a variety of depths, salinities and temperatures, and with probably changed environmental tolerances through history. as pointed out by allmon (2011) turritellid drilled shells indicate that their most frequent drilling predators are naticids, which is in concordance with the fossil data presented here and compared to the other studied samples from the central paratethys area. 6. conclusions information retrieved from the drilled gastropod shells provides a closer insight into the biotic interaction in this part of the pannonian basin system during the badenian. the zaprešić brijeg collections offer the possibility of understanding such biotic interaction due to the abundance of marine gastropod species and the abundance of the drilled shells. there are several gastropod families recognized as predators, which attack other molluscs, and the results of the presented data analysis point to the naticidae and muricidae as the most probable predators. in the studied sample, epifaunal potamididae have the highest number of the drilled shells, with the majority of them being successful. comparing the df of infauna versus epifauna, it is slightly higher in the case of infauna (5.84%, and 5.66%, respectively). df comparison between the feeding type is the highest for the suspension feeders (14.29%), represented mostly by the turritellids, and is lowest for carnivores (3.89%). the average rate of the gastropod df at zaprešić brijeg is 5.72%, which is lower than the badenian gastropods df average of 9.2% for central paratethys as given in sawyer & zuschin (2011, fig. 6a), and gastropods df of 9.65% from the south-eastern margin of the central paratethys (ganić et al., 2016). average gastropods pe of the presented assemblage is 15.15%, which is significantly higher than the pe of 2.2% in the central paratethys (sawyer & zuschin, 2011, fig. 6b), and pe at the southeastern margin of the central paratethys of 7.18% by ganić et al. (2016). comparison of the presented data with previously published data from the neighbouring paratethys areas shows that the badenian gastropod families with higher df in the marginal area of the central paratethys have lower df than the same families in the central paratethys. in addition, the badenian gastropods from marginal areas have higher pe than the average of the central paratethys. the highest df at the zaprešić brijeg is recorded in the infaunal suspension feeding turritellidae, with the most abundant naticid drillings. this is in concordance with their life habitat and known predators from both the fossil and recent data. acknowledgments the authors are grateful to the croatian science foundation project ip-2019-04-7042 (sedimentary paleobasins, water corridors and biota migrations, pi: professor marijan kovačić, faculty of science, university of zagreb) for the support in preparing the manuscript, the reviewers for the helpful suggestions and comments which improved the paper, nives borčić (croatian natural history museum) for taking the photographs of the gastropod specimens, robert košćal (faculty of science, university of zagreb) and mr. renato drempetić for the graphics, and davorka radovčić, phd (croatian natural history museum) for the english language suggestions during the preparation of the ms. g eo lo gi a c ro at ic a geologia croatica 74/3234 references allmon, w.d. (2011): natural history of turritelline gastropods (cerithioidea: turritellidae): a status report.– malacologia, 54/1–2, 159–202. bajraktarević, z. (1978): upper tortonian sediments of zaprešić brijeg near samobor, north croatia (in croatian with english summary).– geološki vjesnik, 30/1, 63–67. http://31.147.204.208/clanci/1978_bajraktarevic_571.pdf bakrač, k., hajek-tadesse, v., miknić, m., grizelj, a., hećimović, i. & kovačić, m. (2010): evidence for badenian local sea level changes in the proximal area of the north croatian basin.– geologia croatica, 63/3, 259–269. doi.org/10.4154/gc.2010.21. bartol, m., mikuž, v. & horvat, a. (2014): palaeontological evidence of communication between the central paratethys and the mediterranean in the late badenian/early serravalian.– palaeogeography, palaeoclimatology, palaeoecology, 394, 144–157. doi.org/10.1016/j.palaeo.2013.12.009. carriker, m.r. (1981): shell penetration and feeding by naticacean and muricacaean predatory gastropods: a synthesis.– malacologia, 20/2, 403–422. casey, m.m. & chattopadhyay, d. (2008): clumping behavior as a strategy against drilling predation: implications for the fossil record.– journal of experimental marine biology and ecology, 367, 174–179. doi:10.1016/j.jembe.2008.09.020. chattopadhyay, d. & baumiller, t.k. (2007): drilling under threat: an experimental assessment of the drilling behavior of nucella lamellosa in the presence of a predator.– journal of experimental marine biology and ecology, 352, 257–266. doi:10.1016/j.jembe.2007.08.001. chattopadhyay, d. & baumiller, t.k. (2010): effect of durophagy on drilling predation: a case study of cenozoic molluscs from north america.– historical biology, 22/4, 367–379. doi: 10.1080/08912961003600445 chattopadhyay, d., sarkar, d., dutta, s. & prasanjit, s.r. (2014): what controls cannibalism in drilling gastropods? a case study on natica tigrina.– palaeogeography, palaeoclimatology, palaeoecology, 410, 126–133. doi. org/10.1016/j.palaeo.2014.05.037. ćorić, s., harzhauser, m., hohenegger, j., mandic, o., pervesler, p., roetzel, r., rögl, f., scholger, r., spezzaferri, s., stingl, k., švábenická, l., zorn, i. & zuschin, m. (2004): stratigraphy and correlation of the grund formation in the molasse basin, northeastern austria (middle miocene, lower badenian).– geologica carpathica, 55/2, 207–215. dávid, á. (1993): trace fossils on molluscs from the molluscan clay (late oligocene, egerian) – a comparison between two localities (wind brickyard, eger, and nyárjas hill, novaj, ne hungary).– scripta geologica, special issue, 2, 75–82. dávid, á. (1999): predation by naticid gastropods on late – oligocene (egerian) molluscs collected from wind brickyard, eger, hungary.– malacological newsletter, 17, 11–19. ganić, m., radović, p., rundić, lj., bradić, k. & knežević, s. (2016): traces of drilling predation in the upper badenian (middle miocene) molluscs from the rakovica stream (belgrade).– geologia croatica, 69/2, 205–212. doi: 10.4154/gc.2016.14. google earth (2001): earth.google.com/web/ gorjanović-kramberger, d. (1894): geology of samoborsko gorje mt. and žumberak mt. (in croatian).– rad yugoslav academy of sciences and arts, 120, 1–82. gorjanović-kramberger, d. (1896): ueber das vorkommen der pereiraia gervaisii vez. sp. in croatien.– verhandlungen der k.k. geologischen reichsanstalt, 142–143. görög, á. & somody, á. (1988): trace fossils on badenian (miocene) gastropods from várpalota, hungary.– annales univ. sci. budapestinensis de rolando eötvös nom. sec. geologica, 28, 121–160. harzhauser, m., mandic, o. & zuschin, m. (2003): changes in paratethyan marine molluscs at the early/middle miocene transition: diversity, palaeogeography and palaeoclimate.– acta geologica polonica, 53, 4, 323−339. harzhauser, m. & piller, w.e. (2007): benchmark data of a changing sea – palaeogeography, palaeobiogeography and events in the central paratethys during the miocene.– palaeogeography, palaeoclimatology, palaeoecology, 253, 8–31. doi.org/10.1016/j.palaeo.2007.03.031. hoffman, a., pisera, a. & ryszkiewicz, m. (1974): predation by muricid and naticid gastropods on the lower tortonian mollusks from the korytnica clays.– acta geologica polonica, 24,/1, 249–260. hoffmeister, a.p. & kowalewski, m. (2001): spatial and environmental variation in the fossil record of drilling predation: a case study from the miocene of central europe.– palaoios, 16, 566–579. doi.org/10.1669/08831351(2001)016<0566:saevit>2.0.co;2. hutchings, j.a. & herbert, g.s. (2013): no honor among snails: conspecific competition leads to incomplete drill holes by a naticid gastropod.– palaeogeography, palaeoclimatology, palaeoecology, 379–380, 32–38. doi.org/10.1016/j.palaeo.2013.04.003. kabat, a.r. (1990): predatory ecology of naticid gastropods with a review of shell boring predation.– malacologia, 32, 1, 155–193. kelley, p.h. & hansen, t.a. (1993): evolution of the naticid gastropod predatorprey system: an evaluation of the hypothesis of escalation.– palaios, 8, 358–375. klompmaker, a.a., kelley, p.h., chattopadhyay, d., clements, j.c., huntley, j.w. & kowalewski, m. (2019): predation in the marine fossil record: studies, data, recognition, environmental factors, and behavior.– earthscience reviews, 194, 472–520. doi.org/10.1016/j.earscirev.2019.02.020 kováč, m., andreyeva-grigorovich, a., bajraktarević, z., brzobohatý, r.,filipescu, s., fodor, l., harzhauser, m., nagymarosy, a., oszczypko, n., pavelić, d., rögl, f., saftić, b., sliva, ľ. & studencka, b. (2007): badenian evolution of the central paratethys sea: paleogeography, climate and eustatic sea level changes.– geologica carpathica, 58/6, 579–606. kováč, m., hudáčková, n., halásová, e., kováčová, m., holcová, k., oszczypko-clowes, m., báldi, k., less, g., nagymarosy, a., ruman, a., klučiar, t. & jamrich, m. (2017): the central paratethys palaeoceanography: a water circulation model based on microfossil proxies, climate, and changes of depositional environment.– acta geologica slovaca, 9/2, 75–114. kováč, m., halásová, e., hudáčková, n., holcová, k., hyžný, m., jamrich, m. & ruman, a. (2018): towards better correlation of the central paratethys regional time scale with the standard geological time scale of the mio cene epoch.– geologica carpathica, 69/3, 283–300. doi: 10.1515/geoca 2018-0017 kowalewski, m. (1990): a hermeneutic analysis of the shell-drilling gastropod predation on mollusks in the korytnica clays (middle miocene; holy cross mountains, central poland).– acta geologica polonica, 40, 3–4, 183–213. kowalewski, m. (2002): the fossil record of predation: an overview of analytical methods.– in: kowalewski, m. & kelley, p.h. (eds.): the fossil record of predation. paleontological special papers, 8, yale university, new haven, 3–42. kowalewski, m. (2004): drill holes produced by the predatory gastropod nucella lamellosa (muricidae): palaeobiological and ecological implications.– journal of molluscan studies, 70/4, 359–370. mađerić, i. (2017): odnos predator-plijen u miocenskim bentičkim zajednicama na lokalitetu zaprešić brijeg kraj samobora [predator-prey relationship in the miocene benthic communities at the zaprešić brijeg locality near samobor – in croatian].– unpubl. bsc thesis, faculty of science, university of zagreb, zagreb, 15 p. mikuž, v. & šoster, a. (2014): several rare miocene gastropods from surroundings of šentjernej in krka basin, slovenia.– folia biologica et geologica, 55/1, 51–72. pahari, a., mondal, s., bardhan, s., sarkar, d., saha, s. & buragohain, d. (2016): subaerial naticid gastropod drilling predation by natica tigrina on the intertidal molluscan community of chandipur, eastern coast of india.– palaeogeography, palaeoclimatology, palaeoecology, 451, 110–123. doi. org/10.1016/j.palaeo.2016.03.020 pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.– basin research, 13, 359–376. pavelić, d. & kovačić, m. (2018): sedimentology and stratigraphy of the neogene rift-type north croatian basin (pannonian basin system, croatia): a review.– marine and petroleum geology, 91, 455–469. doi.org/10.1016/j.marpetgeo.2018.01.026 pavlovsky, m. (1957): ein beitrag zur kenntnis miozäner gastropoden von zaprešić-brijeg bei samobor (in croatian with german summary).– geološki vjesnik, 10 (1956), 51–56. http://31.147.204.208/clanci/1957_pavlovsky_81.pdf pavlovsky, m. (1960): neue elemente der fauna von zaprešić-brijeg bei samobor (in croatian with german summary).– geološki vjesnik, xiii (1959), 213–216. http://31.147.204.208/clanci/1960_pavlovsky_133.pdf piller, w., harzhauser, m. & mandic, o. (2007): miocene central paratethys stratigraphy – current status and future directions.– stratigraphy, 4, 151–168. rögl, f. (1998): palaeogeographic considerations for mediterranean and paratethys seaways (oligocene to miocene).– annalen des naturhistorischen museums in wien, serie a für mineralogie und petrographie, geologie und paläontologie, anthropologie und prähistorie wien, 99 (1997), 279–310. sant, k., palcu, d.v., turco, e., di stefano, a., baldassini, n., kouwenhoven, t., kuiper, k.f. & krijgsman, w. (2019): the mid langhian g eologia c roatica bošnjak et al.: middle miocene serial killers: drilled gastropods from the south-western margin of the central paratethys, croatia 235 flooding in the eastern central paratethys: integrated stratigraphic data from the transylvanian basin and se carpathian foredeep.– international journal of earth sciences, 108, 2209–2232. doi.org/10.1007/s00531-019-01757-z sarkar, d., bardhan, s., mondal, s., das, a., pahari, a., buragohain, d. & saha, s. (2016): predation on recent terebrid gastropods from the indian subcontinent and a spatiotemporal reappraisal based on a revised global database.– malacologia, 59/2, 271–302. http://dx.doi.org/10.4002/040.059.0207 sawyer, j.a. & zuschin, m. (2010): intensities of drilling predation of molluscan assemblages along a transect through the northern gulf of trieste (adriatic sea).– palaeogeography, palaeoclimatology, palaeoecology, 285, 152–173. doi:10.1016/j. palaeo.2009.11.007 sawyer, j.a. & zuschin, m. (2011): drilling predation in mollusks from the lower and middle miocene of the central paratethys.– palaios, 26, 284–297. doi:10.2110/palo.2009.p09-161r šikić, k.; basch, o. & šimunić, a. (1978): osnovna geološka karta sfrj 1:100000, list zagreb l33-80 [basic geological map of sfry 1:100000, zagreb sheet – in croatian].– institut za geološka istraživanja zagreb (1972), savezni geološki zavod, beograd. šikić, k.; basch, o. & šimunić, a. (1979): osnovna geološka kartasfrj 1:100000. tumač za list zagreb l33-80 [basic geological map of sfry 1:100000, geology of the zagreb sheet – in croatian].– institut za geološka istraživanja zagreb (1972), savezni geološki zavod, beograd, 81 p. šuklje, f. (1929): die mediterranfauna des zaprešić brijeg in der samoborska gora in kroatien (in croatian with german summary).– bulletin de l’institut geologique de zagreb, iii, 1–52. tull, d.s. & böhning-gaese, k. (1993): patterns of drilling predation on gastropods of the family turritellidae in the gulf of california.– paleobiology, 19/4, 476–486. vrsaljko, d. (1990): srednjemiocenski gastropodi zaprešić-brijega kraj samobora [the middle miocene gastropods from the zaprešić brijeg locality near samobor – in croatian].– unpubl. m.s. thesis, university of zagreb, zagreb, 52 p. vrsaljko, d., pavelić, d. & bajraktarević, z. (2005): stratigraphy and palaeogeography of miocene deposits from the marginal area of žumberak mt. and the samoborsko gorje mts. (northwestern croatia).– geologia croatica, 58/2, 133–150. https://doi.org/10.4154/gc.2005.07 worms editorial board (2021). world register of marine species. available from https://www.marinespecies.org at vliz. accessed 2021-06-26. doi:10.14284/170 zagyvai, á. & demeter, g. (2001): tracing prey-predatory interactions in the early sarmatian (mid-miocene) shelly community from rollsdorf formation, waldhof, austria based on bioerosional observations.– acta ggm debrecina geology, geomorphology, physical geography series, 3, 51–60. złotnik, m. (2001): size-related changes in predatory behaviour of naticid gastropods from the middle miocene korytnica clays, poland.– acta palaeontologica polonica, 46/1, 87–97. 2019 | 72/2 | 93–100 | 5 figs. | 1 tab. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction paratethys, an intracontinental sea, covered a vast proportion of present-day europe and asia during the miocene (rögl, 1998, 1999; kováč et al., 2017). the north croatian basin (including medvednica mt.; fig. 1), as part of the pannonian basin system, was located in the southwestern part of the central paratethys (pavelić, 2001, 2005; pavelić & kovačić, 2018). this area had a complex geological history, because connections to the mediterranean sea or neotethys and to the eastern paratethys realm were interrupted several times provoking changes in the sedimentary settings. the middle miocene marine transgressive phases, especially the badenian (langhian, lower serravallian) ones, could be easily traced in sediments due to their diverse and abundant fossil content (foraminifera in particular; kováč et al., foraminifera-based estimation of water depth in epicontinental seas: badenian deposits from glavnica gornja (medvednica mt., croatia), central paratethys đurđica pezelj* and lucija drobnjak university of zagreb, faculty of science, department of geology, division of geology and paleontology, horvatovac 102a, 10000 zagreb, croatia; (*corresponding author: djurdjica.pezelj@geol.pmf.hr) doi: 10.4154/gc.2019.08 abstract this study presents the first attempt to estimate the palaeo-depth, and to assess the environmental conditions at the sea bottom, by means of foraminifers during the deposition of earlier badenian deposits in the north croatian basin. the studied stratigraphic record, the glavnica gornja section is located in mt. medvednica, in the southwestern part of the pannonian basin system, and it belongs to the upper lagenidae zone (moravian substage of the badenian). three methods were tested to estimate the palaeo-depth; the plankton/benthos (p/b) ratio indicated the lower to upper bathyal zone, the modified p/b ratio indicated 886-987 m depth for the bathyal zone, whereas the hohenegger method indicated 142-204 m depth for the outer shelf. of the three estimates, the last is considered as best fitting the general environmental demands of the dominant and common small benthic forams. the well oxygenated sea bottom was temporarily replaced by more stressful conditions in the middle part of the studied interval, pointing to occasional variations in the organic flux. 2007; piller et al., 2007). the chronostratigraphic interpretation of the badenian stage is the subject of many debates, with numerous controversies and disagreements. differences include twoor three-part biostratigraphic subdivision of the stage and correlation with sedimentary cycles (kováč et al., 2007, 2018; rögl, 1998; piller et al., 2007; hohenegger et al., 2014; sant et al., 2017). in the north croatian basin, a “layer cake” stratigraphic model was adopted and the classical small benthic foraminifera (sbf) ecozones were applied (fig. 2): lower and upper lagenidae (moravian), spirorutilus (wielician) and buli­ mina­bolivina / ammonia beccarii (kosovian) zones (grill, 1943; papp & turnowsky, 1953; papp et al., 1978; harzhauser & piller, 2007). these ecozones mainly represent article history: manuscript received october 25, 2018 revised manuscript accepted february 14, 2019 available online may 31, 2019 keywords: benthic foraminifera, palaeo-depth estimation, badenian, north croatian basin, central paratethys figure 1. a. sampling locality glavnica gornja, medvednica mt. (šikić, 1995 – modified). b. location of medvednica mt. within the central parathetys during the early badenian (rögl, 1999-modified). g eo lo gi a c ro at ic a geologia croatica 72/294 2. geological setting and description of the studied section medvednica mt. is a 40 km long, southwest to the northeast trending „island mountain“ in the north croatian basin in northwestern croatia (fig. 1.a). the palaeozoic, mesozoic, and palaeogene rocks of the mountain are surrounded by neogene and quaternary sediments (šikić k., 1995; tomljenović, 2008). two concepts are known regarding the date of the initial miocene transgression in the north croatian basin. the older view holds that it occurred during the karpatian (corresponding to the tb 2.2, 3rd order sequence) because ottnangian freshwater deposits directly overlie palaeozoic rocks and are overlain by karpatian marine sediments (šikić et al., 1979; basch, 1983; šikić, 1995: hajek-tadesse, 2009). this view is supported by some recent planktonic foraminiferal data that confirm the karpatian age of the oldest miocene marine sediments (premec-fuček et al., 2017; hernitz kučenjak et al., 2018). according to the second concept (ćorić et al., 2009; pavelić & kovačić, 2018; martinuš et al., 2013; brlek et al., 2016, 2018) however, the beginning of initial marine transgression coincided with the early middle badenian (corresponding to the tb 2.4, 3 rd order sequence), as proved by dating of the čučerje tuffs (14.8 ma; marković, 2017). in this scenario, the continental phase lasted from the ottnangian to the early badenian, and in the early badenian the north croatian basin was characterized by longlived fresh-water lacustrine deposition (fig. 2). in either case, during the initial marine transgression the entire area of medvednica mt. was flooded and only the highest peak was emerged (an island surrounded by the sea). today, the middle miocene (badenian and overlying sarmatian), which forms a more or less continuous sedimentary belt around the mountain core (fig. 1a), the lateral shift of the sedimentary facies (ecological habitats, kováč et al., 2018). the aim of this study is to contribute to the knowledge of environmental conditions during the badenian (lagenidae biochron) in the central paratethys, and to describe the abundance, diversity, composition, and vertical distribution of benthic framiniferal assemblages across different productivity phases. in this paper, special attention is paid to estimation of water depth of the depositional environment. three independent methods were used in order to decide which provides the most realistic estimate. the discrepancies in estimated palaeo-depths obtained using p/b ratio (murray, 1991) or modified p/b ratio (van der zwaan et al., 1990, 1999) method/s and the transfer functional method – hohenegger method – based on known depth ranges of identified benthic foraminifera (hohenegger, 2005) are known for middle miocene deposits of the central paratethys (spezzaferri et al., 2002; hohenegger, 2005; báldi & hohenegger, 2008) and lower miocene karpatian (schlögl et al. 2011). until now, only a few papers dealing with quantified data of badenian sbf from the north croatian basin have been available, and those are mostly focused on the upper badenian (pezelj, 2006, 2007, 2013, 2017, 2018). at the glavnica gornja locality, analysis of the abundance and diversity of sbf assemblages from the upper lagenidae zone along with foraminiferal life-habitats preferences resulted in the reconstruction of sub-environments. thus, our present study, except for some preliminary research (pezelj, 2015; kovačić et al., 2015), presents the first attempt to estimate the palaeo-depths based on quantified data and to describe the sea bottom conditions during the deposition of earlier badenian deposits in the north croatian basin. figure 2. middle miocene local/regional small benthic foraminifera ecozones correlated to the regional and standard stages (modified after pezelj et al., 2013). g eologia c roatica pezelj and drobnjak: foraminifera-based estimation of water depth in epicontinental seas: badenian deposits from glavnica gornja ... 95 is characterized by recognizable transgressive contact, abundance of fossils and great facies diversity due to sea-level oscillations (basch, 1983; šikić, 1995). the beginning of the late badenian coincided with a widespread transgression over older rocks, including the pre-neogene basement, while the badeniansarmatian boundary coincided with partial isolation of the paratethys sea, causing a decrease in salinity and changes in the palaeoenvironment from marine-brackish to brackish (harzhauser & piller, 2007; pavelić & kovačić, 2018). the gornja glavica section is located on the southeast slopes of the central part of medvednica mt. (fig. 1a), and belongs to the so-called „čučerje deposits” (“čučerje development” after kochansky, 1944; kochansky-devidé, 1957). these deposits were considered the oldest and deepest marine sediments of the badenian stratigraphic record in medvednica mt. (avanić, 1997, ćorić et al., 2009, bošnjak et al., 2017). the sedimentary record at glavnica gornja (lat: 45° 56′ 21″ lon: 16° 08′ 23.943″) outcrops along the narrow macadam road leading from glavnica donja village to glavnica gornja village, with a total thickness of 26 m (fig. 3). massive grayish to green marls with scarce fragments of bivalves and echinoids dominate the lower and upper parts of the section. in the central part, structureless massive marls and clay marls are present. occasionally, up to 1 m thick marl layers occur. six samples were taken from the section g1 to g6), from places where lithological changes were observed. 3. methods sediment samples (about 300g each) were soaked in diluted h2o2 for a few hours, and then washed through a sieve system of 0.063, 0.125, 0.25 and 0.5 mm size. the selected fraction for this study was > 0.063 mm. the dried material was repeatedly split with the reich microsplitter until a standard sample of about 300 foraminiferal tests was obtained. after determining the p/b ratio, each sample was split again in order to obtain approximately 300 benthic foraminiferal tests for further quantitative and qualitative analysis. taxonomic identification of foraminifera is in accordance with papp et al. (1978), agip (1982), papp & schmid (1985), loeblich & tappan (1988 a,b), cimerman & langer (1991), cicha et al. (1998), and báldi (1999). determination was corrected according to the up-to-date worms database (world register of marine species, 2019) to exclude invalid names and synonyms. the ecological/palaeoecological preference of each benthic species was taken from murray (1991, 2006), báldi (2006); pezelj et al. (2013, 2016, including all references therein), and others referred to later in the text. species richness, dominant and common species were determined in each sample according to murray (1991). four diversity indices were computed using the past (palaeontology statistic) program (hammer et al., 2001): fisher α index, shannon-wiener index, dominance, and equitability. prior to all analyses and statistical data processing, the benthic foraminiferal assemblages were thoroughly studied to determine their autochtonity (autochtonous vs. allochtonous foraminiferal tests) and the degree of taphonomic alterations on the tests. taphonomic analysis of foraminiferal assemblages was completed using the concept of holcová (1999). for this purpose, size sorting of tests, degree of test fragmentation, abrasion and corrosion were recorded. this procedure also included the recording of stratigraphic ranges and palaeoecological requirements for the identified species. three different methods were used to calculate the palaeodepth: the plankton/benthos ratio, the modified plankton/benthos ratio, and the hohenegger method. the plankton/benthos (p/b) ratio. with the increased distance from the coast, the turbidity decreases, which enables the primary production to increase and consequently leads to an increased amount of the planktonic foraminifera in the system. p/b ratio is expressed as a percentage of planktonic foraminifera in the total foraminiferal community (murray, 1991). the modified plankton/benthos (p/b) ratio (van der zwaan et al., 1990, 1999) is based on the fact that the availability of nutrients at the seafloor usually depends on the water depth. deep infaunal species are excluded from the analysis because they are not directly dependent on the influx of organic matter and food on the sea floor. based on recent research in stressful environments, van hinsbergen et al. (2005) modified the original van der zwaan et al. (1999) formula so that the following taxa are excluded: bolivina (except b. plicatella, b. pseu­ doplicata); bulimina without ribs, uvigerina spp. (except u. semi­ ornata), rectuvigerina, valvulineria, cancris, fursenkoina, stainfortia, globobulimina, and chilostomella. the hohenegger method. hohenegger (2005) and báldi & hohenegger (2008) followed a two-step procedure for estimating palaeo-depth based on the presence/absence of species: (a) information about the distributions of recent species along the depth, and (b) a transfer equation. the bottom water oxygen content was estimated using the bfoi developed by kaiho (1994, 1999). the palaeo productivity was assessed using infaunal/epifaunal ratio. cluster analysis (ward’s method) and non-metric multidimensional scaling (euclidean distance dissimilarity measure) were used for the representation of relationships between samples and species. they were undertaken using the past (palaeontology statiatic) program (hammer et al., 2001), and applied to all identified species of benthic foraminifera. foraminiferal samples are stored at the university of zagreb, faculty of science, department of geology, division of geology and paleontology. 4. results the recovered microfossil assemblages are dominated by foraminifera, while rare ostracod shells and sponge spicules are present, too. foraminiferal assemblages are characterized by wellpreserved tests, considerable species diversity, and abundance of particular species. planktonic foraminiferal tests dominate in all studied samples, comprising more than 85% of the foraminiferal assemblages. the benthic foraminifera are in-situ, their tests are pristine, without corrosion, scraping marks or sorting by test size. altogether, 44 benthic species were identified (table 1): two species belong to sub-order textulariina, one species to the sub-order milioliina, 19 species are affiliated to the sub-order lageniina, and 22 species belong to the rotaliina. species richness ranges from 24 to 30 per sample (fig. 3). samples from the central part of the section (samples g3 and g4) show slightly lower values. toward the central part of the section, values of fisher α index (6.20 8.38), as well as the shannonwiener index (2.50 2.93), decrease, and the same trend is observed with the equitability (0.76 0.87) values. in contrast, dominance (0.07 0.14) reaches the highest values in the samples from the middle of the section (fig. 3). g eo lo gi a c ro at ic a geologia croatica 72/296 the depth estimation based on p/b ratio suggests an upper bathyal environment (85.2 to 92.2 % of planktonic foraminifera). based on the modified p/b ratio the water depth was between 886 and 987 m. according to the third applied model, the hohhenneger method, sedimentation took place at depths ranging from 142 down to 204 m. cluster analysis (ward’s method) and non-metric multidimensional scaling (euclidean distance dissimilarity measure, comparing the composition and abundances of all identified benthic foraminifera species) revealed three clusters, separated into two major groups, group i or the cibicidoides–bolivina assemblage and group ii, the bolivina assemblage, respectively (fig. 4). cluster 1, cibicidoides–bolivina assemblage, contains foraminiferal assemblages from the lower and upper parts of the section (lower samples g1 and g2 and upper samples g5 and g6) and includes 28 30 species. dominant species are cibicidoides ungerianus (average 14.9%), bolivina dilatata (average 12.8%) and b. viennensis (average 10.2%), whereas species c. austriacus (average 9.8%) and l. inornata (average 5.5%), while still common, are less abundant. cluster 2, bolivina assemblage, comprises samples from the central part of the section and consists of 24 27 species. it is characterized by the greater abundance of bolivina dilatata (average 29.9%) and b. viennensis (average 15.3%). still prominent, but less abundant within this cluster are c. ungerianus (average 9.7%), c. austriacus (average 5.2%) and melonis pompilioides (average 5.2%). benthic foraminiferal oxygen index values from 19.89 to 65.00 (bfoi, fig. 3) suggest that a shift in oxygen content took place during deposition. sediments from the lower and upper parts of the section originated during high oxic conditions. moderate oxic conditions prevailed during sedimentation of the central part of the section, and the lowest concentration of oxygen occurred during sedimentation of sample g4, approaching lowoxic conditions. suboxic species (comprising 35.7 to 51.1% of the total benthic assemblage) and oxic indicators (varying from 12.3 to 31.8%) prevail in the lower and upper parts of the section, while in the middle part of the section an increase in the proportion of disoxic indicators (17.2 49.7%) was observed. within the benthic community, infaunal forms (53.4 77.7%) dominate, especially in the central part of the section. 5. stratigraphy in this paper, the standard biozonation scheme (fig. 2) for the miocene of the central paratethys was applied (papp et al., 1978; papp & schmid, 1985; cicha et al., 1998; piller et al., 2007) along with the badenian stratigraphic correlation table proposed by hohenegger, 2014; kováč, 2018 and pavelić & kovačić, 2018 (for north croatian basin). it has to be stressed that recently, for dating of the miocene deposits of the north croatian basin, the sub-division model by hohenegger et al. (2014) was used, in which the moravian sub-stage is correlated with the lower and middle badenian (fig. 2). however, this proposal is still subject to numerous discussions and is not unanimously accepted (holcová, 2018). the early badenian age of the studied samples was confirm ed by the presence of uvigerina macrocarinata papp & turnovski as well as by various lageniids (fig. 5; table 1), some of which are index fossils for this sub-age (sensu cicha et al., 1998), such as planularia dentata (karrer) and p. lanceolata (d’orbigny). the occurrence of uvigerina grilli schmid, dentalina acuta d’orbigny, and pseudonodosaria brevis d’orbigny is typitable 1. list of identified species of benthic foraminifera, their abundance in samples and ecological/palaeoecological interpretation (o-oxic, s-suboxic, d-disoxic; e-epifauna. si-shallow infauna, i-infauna). species / sample g1 g2 g3 g4 g5 g6 amphicoryna badenensis (d´orbigny) 0 4 0 0 0 1 s/i amphicoryna hispida (d´orbigny) 1 0 0 0 0 1 s/i anomalinoides sp. 10 4 11 12 9 7 o/e bolivina antiqua d´orbigny 0 0 0 2 0 0 d/i bolivina dilatata reuss 41 31 93 81 42 32 d/i bolivina viennensis marks 26 18 35 54 30 41 d/i bulimina elongata d´orbigny 0 3 0 10 5 3 d/i bulimina striata d´orbigny 2 12 3 0 10 9 d/i cassidulina laevigata d´orbigny 0 3 7 0 9 12 s/i caveastomella adolphina (d´orbigny) 9 5 6 7 1 0 s/i ceratocancris hauerii (d´orbigny) 10 11 0 0 0 0 s/i cibicidoides austriacus (d´orbigny) 21 32 16 14 31 28 o/e-si cibicidoides ungerianus (d´orbigny) 52 43 35 21 45 30 o/e-si chilostomella ovoidea reuss 7 0 0 8 1 0 d/i dentalina acuta d´orbigny 1 0 0 0 0 2 s/i fursenkoina subacuta (d´orbigny) 6 6 0 0 1 3 d/i glandulina ovula d´orbigny 0 0 0 0 2 0 s/i globocassidulina crassa (d’orbigny) 0 5 4 0 8 10 o/i grigelis pyrulus (d´orbigny) 0 1 0 0 1 0 s/i hansenisca soldanii d´orbigny 4 0 6 5 8 8 s/e heterolepa dutemplei d´orbigny 6 0 1 0 3 0 o/e hoeglundina elegans (d´orbigny) 3 0 0 0 0 0 s/e laevidentalina communis (d´orbigny) 0 0 0 3 2 1 s/i laevidentalina elegans d´orbigny 0 3 5 2 7 0 s/i lenticulina inornata (d´orbigny) 15 21 10 11 12 15 o/si lenticulina vortex (fichtell & moll) 0 2 1 0 0 2 o/e marginulina hirsuta d´orbigny 2 0 4 5 3 0 s/i martinottiella communis (d´orbigny) 2 0 1 0 0 1 o/e melonis pompilioides (fichtell & moll) 11 8 14 16 14 18 s/i neugeborina longiscata (d´orbigny) 9 5 10 6 0 0 s/i nonion commune (d´orbigny) 0 5 9 0 2 0 s/i planularia casis (fichtell & moll) 0 0 0 0 1 3 s/i planularia dentata (karrer) 0 13 0 0 0 1 s/i planularia lanceolata (d´orbigny) 0 1 0 0 0 2 s/i planulina sp. 3 4 2 0 1 3 o/e pseudonodosaria brevis d´orbigny 3 4 2 0 0 4 s/i pullenia bulloides (d´orbigny) 15 21 3 15 4 15 s/i saracenaria arcuata (d´orbigny) 0 6 0 4 0 0 s/i spirosigmoilina tenuis (cžjžek) 2 7 0 1 4 8 o/e textularia gramen d´orbigny 8 5 2 1 0 2 s/i trifarina angulosa (williamson) 14 22 5 9 15 17 o/i uvigerina grilli schmid 2 0 0 2 1 0 d/i uvigerina macrocarinata papp & turnovski 1 0 0 1 0 0 d/i vaginulinopsis pedum (d´orbigny) 1 0 3 2 1 0 s/i summ 308 293 301 303 299 304 g eologia c roatica pezelj and drobnjak: foraminifera-based estimation of water depth in epicontinental seas: badenian deposits from glavnica gornja ... 97 cal for the early and middle badenian, and vaginulinopsis pedum (d’orbigny) is typical for the karpatian and early badenian. according to the standard small benthic ecobiozonation scheme (fig. 2), our samples belong to the lagenidae zone (moravian, lower badenian). presence of the planktonic foraminifera species orbulina suturalis brönnimann indicate a maximum depositional age of 14.56 ma (the fo datum of orbulina sutura­ lis in the mediterranean; iaccarino et al., 2012). therefore, the studied stratigraphic interval certainly correlates with the upper lagenidae zone, of the middle badenian (sensu hohenegger et al., 2014; sensu pavelić & kovačić, 2018 for north croatian basin), and can be correlated with the middle miocene sea level cycle tb 2.4 (fig. 2). 6. discussion the middle part of the glavnica gornja section reflects environmental changes, as the cibicidoides­bolivina assemblage is replaced by the bolivina assemblage. changes in the foraminiferal composition and species richness correspond to a decrease of diversity indices (fisher α index, shannon-wiener index, equitability) in the central part of the section, and a consequent increase in dominance (fig. 3). these changes could be related to more stressful conditions at the sea-bed. it would be reasonable to assume that they were triggered by changes in water depth. the abundance of planktonic foraminifera in the samples varies from 85.2% to 92.2%, and undoubtedly points to a good connections to the open sea. these very high values are indicative of the upper bathyal zone (murray, 1991), and the highest values, above 90%, for the lower bathyal zone (valchev, 2003). the ratio of p/b is a good proxy for water depth estimation, because the number of planktonic foraminifera increases with distance from the coast (grimsdale & morkhoven, 1955, murray, 1991). thus, the percentage of planktonic foraminifera within the fossil assemblages should indicate the water depth, but this is not a linear function (van hinsbergen et al., 2005). sometimes a high percentage of planktonic fora minifera can be present in shallow water environments as a consquence of predominating onshore winds (vella, 1962). the p/b ratio is not affected solely by the water depths; selective dissolution of planktonic tests and changes in the amount of dissolved oxygen at the sea-bed may also control the p/b ratio (sen-gupta & machan-castillo, 1993; jorissen et al., 1995, figure 3. glavnica gornja section with sampling points (g), number of benthic foraminifera species, diversity indices (fisher α index, shannon-wiener index, equitability, dominance), oxic disoxic indicators, epifauna/infauna ratio, bfoi, estimated depths of sedimentary basin after hohenegger method and modified p/b ratio, and percentage of planktonic taxa. figure 4. cluster analysis (ward’s method) and non-metric multidimensional scaling (euclidean). g eo lo gi a c ro at ic a geologia croatica 72/298 kouwenoven et al., 2003). it is known how reduced oxygenation at the seabed affects the quantity and quality of available food (nutrient composition) and causes an increase in the proportion of organic matter in the sediment (gooday et al., 2000). this leads to a drop in the abundance of less tolerant species, especially those that are epifaunal (de stigter et al., 1996). in contrast, species adapted to oxygen deficiency thrive because of an increase in nutrients (jorissen, 1999; duijnstee et al., 2004). under oxygen-deficient (unfavourable) conditions, deep infaunal species may dominate and for this reason the modified p/b ratio (van der zwaan et al., 1990, 1999) method excludes them. the calculated water depth for glavnica gornja samples, based on the modified p/b ratio, is between 886 to 987m, which corresponds to the middle bathyal zone of the mediterranean continental slope (einig, 1997). such great depths, however, do not fit with the depth range distribution of the identified benthic foraminifera, because their depth ranges coincide (overlap) with the outer shelf range. the absence or low abundance of typical bathyal and deeper water taxa (in particular uvigerina and agglutinated forms) certainly indicates shallower conditions than those suggested by the modified p/b ratio. the hohenegger method for estimation of palaeo-depth (hohenegger, 2005, báldi & hohenegger, 2008) is based on the depth range of recent species of benthic foraminifera. in any case, it should be emphasized that it is impossible to construct a general scheme of depth zoning that would be applicable to all areas of the world, because the species depth range depends on local physico-chemical and biological conditions. any particular species will be most abundant where the optimum ecological conditions are developed for them (murray, 2006). therefore, in the palaeoecological reconstruction, the ecological demand of the dominant and common species should be consiedered in the first place. at the glavnica gornja locality, palaeo-depths obtained by the hohenegger method range from 142 to 204 m and indicate the outer shelf, which is far more realistic than the results of the p/b and modified p/b methods. we can speculate that the high percentage of planktonic foraminifera in our samples suggests the predominance of onshore winds or increased primary production. regardless of the differences in the obtained water depth values (fig. 3) it is evident that all three methods show only minor oscillations in the depth of the depositional environment. the change in foraminiferal assemblages in the central part of the section thus cannot be attributed to changes in the palaeo-depth. what does the small benthic foraminifera of the glavnica gornja section suggest about the amount of oxygen at the sea bed? the values of bfoi (fig. 3) indicate that highly oxic conditions prevailed during sedimentation of the upper and lower parts of the section. good water circulation throughout the water column ensured oxygenation of sea-bottom water, and suggests that the local climate could be certainly warm (increased evaporation over precipitation and river influx to the basin). oxic indicative species, such as c. ungerianus, c. austriacus and l. inornata (table 1) were common within the cibicidoides­bolivina assemblage. in the central part of the section (bolivina assemblage) a reduction in oxygen content occurred. moderate to almost low oxic conditions (sample g 4) are defined based on bfoi indices. also, the apparent increase in the proportion of disoxic species and infaunal forms (fig. 3) (b. dilatata, b. viennensis and b. elon­ gata) suggests that there could be a change in the quantity and quality of available food. it is possible to assume that organic matter and nutrients were brought into the sedimentation system either due to increased primary production or to increased terrigenous influx. the results of analysis of small benthic foraminiferal assemblages from this study generally coincide with the results obtained from other badenian sites of the central parathetys (kováčová & hudáčková, 2005; báldi & hohenegger, 2008; báldi 2006; kopecka 2012; peryt 2013; pezelj 2013; doláková et al., 2014, 2015; rybar et al., 2015; nehyba et al., 2016). in the early badenian, an antiestuarine circulation pattern with a weakly stratified or non-stratified water column and well-ventilated sea bottom developed, supporting a relatively diverse assemblage of benthic foraminifera (báldi, 2006; kováč et al., 2007, kováč et al., 2017, 2018). at the glavnica gornja locality, a more stable, deep water environment (ca. 200 m) was established after the tb 2.4 transgression. it was characterized by occasional episodes of minor oscillations in water depth and fluctuations in the intensity of primary production or terrigenous influx. 7. conclusions diverse and abundant assemblages of small benthic foraminifera (44 species) thrived during the badenian (upper lagenidae biochron) in the area of the glavnica gornja section (medvednica mt.). the calculation of water depth by different methods highlighted that the hohenegger method produced the most plausible results (outer shelf) and thus it can be considered a reliable method for estimating water depth in epicontinental seas such as figure 5. selected benthic foraminiferal species from glavnica gornja. 1. vaginulinopsis pedum (d’orbigny), sample g3: 2. amphicoryna badenensis (d’orbigny). sample g2; 3. planularia lanceolata (d’orbigny), sample g6; 4. lenticulina vortex (fichtell & moll), sample g6; 5. planularia dentata (karrer), sample g2; 6. pseudonodosaria brevis d´orbigny, sample g2; 7. marginulina hirsuta d´orbigny, sample g5; 8. glandulina ovula d´orbigny, sample g5. g eologia c roatica pezelj and drobnjak: foraminifera-based estimation of water depth in epicontinental seas: badenian deposits from glavnica gornja ... 99 the central paratethys. high oxic conditions (cibicidoides­bo­ livina assemblage) prevailed at the sea-bed, whereas the central part of the section (bolivina assemblage) reflects moderate to nearly low oxic conditions. the succession of foraminiferal assemblages illustrates the interplay between oxygen and food availability, where a decrease of oxygen correlates to an increase in organic matter and nutrients. stressed conditions in the central part of the section were also confirmed by the decrease in diversity and increasing importance of dominance within the benthic foraminiferal assemblage as well as a significant increase in the proportion of disoxic and infaunal forms. the most important factors influencing the distribution of benthic foraminifera in the studied section are fluctuations in the amount of oxygen available at the sea bottom and/or flux of organic matter and nutrients into the environment, while minor oscillations in water depth are not reflected in the changes of the foraminiferal assemblages. acknowledgement many thanks go to n. hudáčková and an anonymous reviewer for critical suggestions helping to improve the manuscript. the authors are grateful to an anonymous associate editor and v. ćosović for helpful comments and suggestions. references agip s.p.a. (1982): foraminiferi padani (terziaro e quateriniario).– carlo saccardo & figli, milano, 52 p. avanić, r. (1997): analiza facijesa srednjeg miocena jugoistočnog dijela medvednice [middle miocene facies analysis of of southeastern part of medvednica mt. – in croatian, with an english abstract].– unpubl. master thesis, faculty of science, university of zagreb, zagreb, 54 p. báldi, k. & hohenegger, j. (2008): palaeoecology of benthic foraminifera of the baden – sooss section (badenian, middle miocene, vienna basin, austria).– geol. carpath., 59/5, 411–424. báldi, k. (2006): pleoceanography and climate of the badenian (middle miocene, 16.4-13.0 ma) in the central paratethys based on foraminifera and stable isotope (δ18 o and δ13 c) evidence.– int. j. earth sci. (geol. rundsch.), 95, 119–142. báldi, k. (1999): taxonomic notes on benthic foraminifera from sw-hungary, middle miocene (badenian) paratethys.– acta geol. hungar., 42/2, 193–236. basch, o. (1983): osnovna geološka karta sfrj, 1:100.000, tumač za list ivanić grad l 33-81 [basic geological map of sfry 1:100000, geology of the ivanić grad sheet – in croatian].– inst. geol. istraž., zagreb, savezni geološki zavod, beograd, 66 p. bošnjak, m., sremac, j., vrsaljko, d., aščić, š. & bosak, l. (2017). the miocene “pteropod event” in the sw part of the central paratethys (medvednica mt., northern croatia).– geol. carpath., 68/4, 329–349. brlek, m., iveša, l., brčić, v., santos, a., ćorić, s., milošević, m., avanić, r., devescovi, m., pezelj, đ., mišur, i. & miknić, m. (2018): rocky-shore unconformities marking the base of badenian (middle miocene) transgressions on mt. medvednica basement (north croatian basin, central pa ra tethys).– facies, 64/3, 1–25. doi: 10.1007/s10347-018-0537-0. brlek, m., špišić, m., brčić, v., mišur, i., kurečić, t., miknić, m., avanić, r., vrsaljko, d. & slovenec, da. (2016): mid-miocene (badenian) transgression on mesozoic basement rocks in the mt. medvednica area of northern croatia.– facies, 62/3, 1–18. doi: 10.1007/s10347-016-0470-z cicha, i., rögl, f., rupp, c. & ctyroka, j. (1998): oligocene-miocene foraminifera of the central paratethys.– abh. senckenberg. naturforsch. ges., 549, 1–325. cimerman, f. & langer, m.r. (1991): mediterranean foraminifera.– prir. istraž. slov. akad. znan. umjetn., 30, 1–118. ćorić, s., pavelić, d., rögl, f., mandic, o., vrabac, s., avanić, r., jerković, l. & vranjkovic, a. (2009): revised middle miocene datum for initial marine flooding of north croatian basins (pannonian basin system, central paratethys).– geol. croat., 62/1, 31–43. doi: 10.4154/gc.2009.03 de stigter, h.c., jorissen, f.j. & van der zwaan, g.j. (1996): modelling the population dynamics of benthic foraminiferal communities under seasonally fluctuating bottom water oxygen concentrations.– geol. ultraiect., 144, 179–208. doláková, n., holcová, k., nehyba, s., hladilová, š., brzobohatý, r., zágoršek, k., hrabovský, j., seko, m. & utescher, t. (2014): the badenian parastratotype at židlochovice from the perspective of the multiproxy study.– neues jahrb. geol. p.-a., 271/2, 169–201. duijnstee, i.a.p., de lugt, i., vonk noordegraaf, h. & van der zwaan, b. (2004): temporal variability of foraminiferal densities in the northern adriatic sea.– mar. micropalaeontol., 50, 125–148. doi: 10.1016/s0377-8398(03) 00069-0 einig, с.с. (1997). bathyal zones of the mediterranean continental slope: an attempt.– publ. espec. inst. esp. oceanogr., 23, 23–33. gooday, a.j., bernhard, j.m., levin, l.a. & suhr, s.b. (2000): foraminifera in the arabian sea oxygen minimum zone and other oxygen-deficient settings: taxonomic composition, diversity, and relation to metazoan faunas.– deep-sea res. ii, 47, 25–54. doi: 10.1016/s0967-0645(99)00099-5 grill, r. (1941): stratigraphische untersuchungen mit hilfe von mikrofaunen im wiener becken und den benachbarten molasse-anteilen.– oel. u. köhle berlin, 595–602. grimsdale, t.f. & morkhoven, f.p.c.m. (1955): the ratio between pelagic and benthonic foraminifera as a means of estimating depth of deposition of sedimentary rocks.– proc. world petroleum cong. 4th, rome, 4/1, 473–491. hajek-tadesse, v., belak, m., sremac, j., vrsaljko, d. & wacha, l. (2009): early miocene ostracods from the sadovi section (mt pozeska gora, croatia).– geol. carpath., 60, 251–262. doi: 10.2478/v10096-009-0017-0. hammer, o., harper, d.a.t. & ryan, p.d. (2001): past: palaeontological statistics software package for education and data analysis.– palaeol. electron., 4/1 (9pp. ://palaeoelectronica.org/2001_1/past/issue1_01.htm). harzhauser, m. & piller, w.e. (2007): benchmark data of a changing sea–palaeogeography, palaeobiogeography and events in the central paratethys during the miocene.– palaeogeogr. palaeoclimatol. palaeoecol., 253/1–2, 8–31. hernitz kučenjak, m., premec fućek, v., krizmanić, k., tadej, j., zlatar, s. & matošević, m. (2018): karpatian and badenian transgression in croatian part of the pannonian basin system (biostratigraphy and palaeoenvironments).– in: forams 2018 international symposium on foraminifera. foraminifera in a changing world. temporary abstracts collection, edinburgh. hohenegger, j., ćorić, s. & wagreich, m. (2014): timing of the middle miocene badenian stage of the central paratethys.– geol. carpath., 65/1, 55–66. doi: 10.2478/geoca-2014-0004 hohenegger, j. (2005): estimation of environmental palaeogradient values based on presence/absence data: a case study using benthic foraminifera for palaeodepth estimation.– palaeogeogr. palaeoclimatol. palaeoecol., 217, 115–130. holcová, k., doláková, n., nehyba, s. & vacek, f. (2018): timing of langhian bioevents in the carpathian foredeep and northern pannonian basin in relation to oceanographic, tectonic and climatic processes.– geol. q., 62/1, 3–17. doi: 10.7306/gq.1399 holcová, k., brzobohatý, r., kopecká, j. & nehyba, s. (2015): reconstruction of the unusual middle miocene (badenian) palaeoenvironment of the carpathian foredeep (lomnice/tišnov denudational relict, czech republic).– geol. q., 59/4, 654–678. holcová, k. (1999): postmortem transport and resedimentation of foraminiferal tests: relations to cyclical changes of foraminiferal assemblages.– palaeogeogr. palaeoclimatol. palaeoecol., 145/1–3, 157–182. doi: 10.1016/s0031-0182(98)00100-x iaccarino, s.m., di stefano, a., foresi, l.m., turco, e., baldassini, n., cascella, a., da prato, s., ferraro, l., gennari, r., hilgen f.j., lirer, f., maniscalco, r., mazzei, r., riforgiato, f., russo, b., sagnotti, l., salvatorini, g., speranza, f. & verducci, m. (2012): high-resolution intergrated stratigraphy of the upper burdigalian-lower langhian in the mediterranean: the langhian historical stratotype and new candidate sections for defining its gssp.– stratigraphy, 8, 195–215. jorissen, f.j. (1999): benthic foraminiferal successions across late quaternary mediterranean sapropels.– mar. geol., 153, 91–101. doi: 10.1016/s0025-3227 (98)000887 jorissen, f.j., de stigter, h.c. & widmark, j.g.v. (1995): a conceptual model explaining benthic foraminiferal microhabitats.– mar. micropalaeontol., 26, 3–15. doi: 10.1016/0377-8398(95)00047-x kaiho, k. (1999): effect of organic carbon flux and dissolved oxygen on the benthic foraminiferal oxygen index (bfoi).– mar. micropalaeontol., 37, 67–76. doi: 10.1016/ s0377-8398(99)00008-0 kaiho, k. (1994): benthic foraminiferal dissolved-oxygen index and dissolved-oxygen levels in the modern ocean.– geology, 22, 719–722. doi: 10.1130/0091-7613(1994) 022%3c0719:bfdoia%3e2.3.co;2 kochansky-devidé, v. (1957): o fauni miocena i o tortonskom “šliru” medvednice (zagrebačka gora) [about miocene fauna and tortonian “schlier” of medvednica mt. (zagrebačka gora) – in croatian].– geol. vjesnik, 10, 39–50. kochansky, v. (1944): fauna marinskog miocena južnog pobočja medvednice (zagrebačke gore) [marine miocene fauna from southern slopes of medvednica mt, (zagrebačka gora)– in croatian].– vjestnik hrv.– drž. geol. zavoda i hrv. drž. geol. muzeja, 2/3, 171–280. kopecká, j. (2012): foraminifera as environmental proxies of the middle miocene (early badenian) sediments of the central depression (central paratethys, moravian part of the carpathian foredeep).– bull. geosc., 87/3, 431–442. doi: 10.3140/bull.geosci.1299 kouwenhoven, t.j., hilgen, f.j. & van der zwaan, g.j. (2003): late tortonian – early messinian stepwise disruption of the mediterranean – atlantic connections: constrains from benthic foraminiferal and geochemical data.– palaeogeogr. palaeoclimatol. palaeoecol., 198, 303–319. doi: 10.1016/s0031-0182(03)00472-3 g eo lo gi a c ro at ic a geologia croatica 72/2100 kováč, m., halásová, e., hudáčková, n., holcová, k., hyžný, m., jamrich, m. & ruman, a. (2018): towards better correlation of the central paratethys regional time scale with the standard geological time scale of the miocene epoch.– geol. carpath., 69/3, 283–300. kováč, m., hudáčková, n., halásová, e., kováčová, m., holcová, k., oszczypko-clowes, m., báldi, k., less, g., nagymarosy, a., ruman, a., klučiar, t. & jamrich, m. (2017): the central paratethys palaeoceanography: a water circulation model based on microfossil proxies, climate, and changes of depositional environment.– acta geol. slov., 9/2, 75–114. kováč, m., andreyeva-grigorovich, a., bajraktarević, z., brzobohatŷ, filipescu, s., fodor, l., harzhauser, m., nagymarosy, a., oszczypko, n., pavelić, d., rögl, f., saftić, b., sliva, l. & studencka, b. (2007): badenian evolution of the central paratethys sea: palaeogeography, climate and eustatic sea-level changes.– geol. carpath., 58/6, 579–606. kovačić, m., marković, f., ćorić, s., pezelj, đ., hernitz-kučenjak, m., premec-fućek, v. & balen, d. (2015): geological section nježić badenian marine sediments with tuff.– in: horvat, m. & galović, l. (eds.): excursion guide-book. 5th croatian geological congress, osijek. croatian geological survey, zagreb, 44–47. kováčová, p. & hudáčková, n. (2005): lower/middle badenian foraminiferal associations from the vienna basin (slovak part) and carpathian foredeep: biostratigraphy and palaeoecology. – slovak geol. magazine, 11/4, 233–248. loeblich, a.r. & tappan, h. (1988a): foraminiferal genera and their classification.– van nostrand reinhold, new york, 970 p. doi: 10.1007/978-1-4899-5760-3 loeblich, a.r. & tappan, h. (1988b): foraminiferal genera and their classification. plates.– van nostrand reinhold, new york, 1059 p. marković, f. (2017): miocenski tufovi sjevrnohrvatskog bazena [miocene tuffs of the north croatian basin – in croatian, with an english abstract].– unpubl. phd thesis, faculty of science, university of zagreb, 170 p. martinuš, m., fio, k., pikelj, k. & aščić, š. (2013): miocene warm-temperate carbonates of central paratethys (mt. zrinska gora, croatia): palaeoenvironmental reconstruction based on bryozoans, coralline red algae, foraminifera, and calcareous nannoplankton.– facies, 59, 481–504. doi: 10.1007/s10347-012-0327-z murray, j.w. (2006): ecology and applications of benthic foraminifera. cambridge – university press, cambridge, 438 p. doi: 10.1017/cbo9780511535529 murray, j.w. (1991): ecology and palaeoecology of benthic foraminifera. longman – scientific and tehnical, harlow, essex, 397 p. nehyba, s., holcová, k., gedl, p. & doláková, n. (2016): the lower badenian transgressive-regressive cycles–a case study from oslavany (carpathian foredeep, czech republic).– neues jahrb. geol. p.-a., 279 /2, 209–238. papp, a. & schmid, m.e. (1985): the fossil foraminifera of the tertiary basin of vienna. die fossilen foraminiferen des tertiaren bekens von wien.– abh. geologisch. bundesanst., band 37, 1–311. papp, a. & cicha, i. (1978): 4. definition der zeiteinheit m – badenien.– in: papp, a., cicha, i., seneš, j. & steininger, f. (eds.): m4–badenien (moravien, wielicien, kosovien). chronostratigraphie und neostratotypen, miozän der zentralen paratethys. 6. veda, bratislava, 47–48. papp, a. & turnovsky, k. (1953): die entwicklung der uvigerinen im vindobon (helvet und torton) des wiener beckens.– jahrb. geol. bund., wien 96, 117–142. papp, a., cicha, i. & čtyroká, j. (1978): foraminifera.– in: papp, a., cicha, i., seneš, j. & steininger, f. (eds.): chronostratigraphie und neostratotypen miozän der zentralen parathetys. badenian, verlag der slowak. akad. der wissen., bratislava, 263–325. pavelić, d. (2005): cyclicity in the evolution of the neogene north croatian basin (pannonian basin system).– in: mabesoone, j.m. & neumann, v.h. (eds.): cyclic development of sedimentary basins. dev. sedim., elsevier, 57, 273–283. doi: 10.1016/s0070-4571(05)80011-1 pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.– basin res. 13, 359–376. doi: 10.1046/j .0950 -091x .2001 .00155. pavelić, d. & kovačić, m. (2018): sedimentology and stratigraphy of the neogene rift-type north croatian basin (pannonian basin system, croatia): a review.– mar. petrol. geol., 91, 455–469. doi: 10.1016/j.marpetgeo.2018.01.026 peryt, d. (2013): foraminiferal record of the middle miocene climate transition prior to the badenian salinity crisis in the polish carpathian foredeep basin (central paratethys).– geol. q., 57/1, 141–164. doi: 10.7306/gq.1080 pezelj, d. (2018): evidence of seasonality in middle miocene central paratethys shallow marine shelf – recorded by benthic foraminifera.– in: forams 2018 international symposium on foraminifera, foraminifera in a changing world. temporary abstracts collection, edinburgh. pezelj, đ., sremac, j., kovačić, m., alagić, s. & kampić, š. (2017): middle miocene badenian-sarmatian sedimentary sequence in the area of donje orešje/ medvednica mt., croatia.– in: horvat, m. & wacha, l. (eds.): 7th international workshop, neogene of central and south-eastern europe, abstracts book, may 2017, velika, croatia, 46-47. pezelj, đ., sremac, j. & bermanec, v. (2016): shallow-water benthic foraminiferal assemblages and their response to the palaeoenvironmental changes-example from the middle miocene of medvednica mt. (croatia, central paratethys).– geol. carpath., 67/4, 329–345. doi: 10.1515/geoca-2016-0021 pezelj, d. (2015): donjobadenske bentičke foraminifere lokaliteta glavnica gornja [ear­ ly badenian benthic foraminifera from glavnica gornja locality – in croatian].– in: mauch lenardić, j., hernitz kučenjak, m., premec fućek, v. & sremac, j. (eds.): international scientific meeting 100th birth anniversary of vanda kochansky-devidé, full member of academy, zagreb, hazu, 72–73. pezelj, d., mandic, o. & coric, s. (2013): palaeoenvironmental dynamics in the southern pannonian basin during initial middle miocene marine flooding.– geol. carpath., 64/1, 81–100. pezelj, đ., sremac, j. & sokač, a. (2007): palaeoecology of the late badenian foraminifera and ostracoda from the sw central paratethys (medvednica mt., croatia).– geol. croat., 60/2, 139–150. pezelj, đ. (2006): palaeoekološki odnosi badena i sarmata, planina medvednica [pala­ eoecological relationship beetwen badenian and sarmatian deposits from the med­ vednica mt. – in croatian, with an english abstract].– unpubl. phd thesis, faculty of science, university of zagreb, 132 p. piller, w.e., harzhauser, m. & mandic, o. (2007): miocene central paratethys stratigraphy – current status and future directions.– stratigraphy, 4, 151–168. premec fućek, v., hernitz kučenjak, m., krizmanić, k., tadej, j. & zlatar, s. (2017): controversies on karpatian and badenian transgressions in croatian part of the pannonian basin system (biostratigraphy and palaeoenvironments).– in: horvat, m. & wacha, l. (eds.): 7th international workshop, neogene of central and south-eastern europe, abstracts book, may 2017, velika, croatia, 50–51. rögl, f. (1999): mediterranean and paratethys. facts and hypotheses of an oligocene to miocene palaeogeography (short overview).– geol. carpathica, 50/4, 339–349. rögl, f. (1998): palaeographic consideration for mediterranean and paratethys seaways (oligocene to miocene).– ann. naturhist. mus., 99a, 279–310. rybár, s., halásová, e., hudáčková, n., kováč, m., kováčová, m., šarinová, k. & šujan, m. (2015): biostratigraphy, sedimentology and palaeoenvironments of the northern danube basin: ratkovce 1 well case study.– geol. carpath., 66/1, 51–67. sant, k., v. palcu, d., mandic, o. & krijgsman, w. (2017): changing seas in the early–middle miocene of central europe: a mediterranean approach to paratethyan stratigraphy.– terra nova, 29/5, 273–281. sen gupta, b.k. & machain-castillo, m.l. (1993): benthic foraminifera in oxygen poor habits.– mar. micropalaeontol., 20/1, 183–201. schlögl, j., chirat, r., balter, v., joachimski, m., hudáčková, n. & quillévéré, f. (2011): aturia from the miocene paratethys: an exceptional window on nautilid habitat and lifestyle.– palaeogeogr., palaeoclimatol., palaeoecol., 308/3, 330–338. doi: 10.1016/j.palaeo.2011.05.037 spezzaferri, s., coric, s., hohenegger, j. & rögl, f. (2002): basin-scale palaeobiogeography and palaeoecology: an example from karpatian (latest burdigalian) benthic and planktonic foraminifera and calcareous nannofossils from the central paratethys.– geobios, 24, 241–256. šikić, k. (1995): prikaz geološke građe medvednice (geological composition of the med­ vednica mt. – in croatian).– in: šikić, k. (ed.): geološki vodič medvednice. inst. geol. istraž., zagreb, 7–30. šikić, k., basch, o. & šimunić, a. (1978): osnovna geološka karta sfrj 1:100.000. tumač za list zagreb l 33-80 [basic geological map of sfry 1:100000, geology of the zagreb sheet – in croatian].– inst. geol. istraž., zagreb (1972), savezni geološki zavod, beograd, 81 p. tomljenović, b., csontos, l., márton, e. & márton, p. (2008): tectonic evolution of the northwestern internal dinarides as constrained by structures and rotation of medvednica mountains, north croatia.– in: fügenschuh, b., froitzheim, n. & siegesmund, s. (eds.): tectonic aspects of the alpine-dinaride-carpathian system, 298. geological society, special publications, london, 145–167. doi: 10.1144/sp298.8 valchev, b. (2003): on the potential of small benthic foraminifera as palaeoecological indicators: recent advances.– ann. umg, 46, part і, geol. and geophys., 51–56. van der zwaan, g.j., dujinstee, i.a.p., den dulk, m., ernst, s.r., jannink, n.t. & kouwenhoven, t.j. (1999): benthic foraminiferes: proxies or problems? a review of palaeoecological concepts.– earth scien. rev., 46, 213–236. van der zwaan, g.j., jorissen, f.j. & de stigter, h.c. (1990): the depth dependency of planktonic/benthic foraminiferal ratios: constrains and applications.– mar. geol., 95, 1–16. doi: 10.1016/0025-3227(90)90016-d van hinsbergen, d.j.j., kouwenhoven, t.j. & van der zwaan, g.j. (2005): palaeobathymetry in the backstripping procedure: correction for oxygenation effects on depth estimates.– palaeogeogr. palaeoclimatol. palaeoecol., 221, 245–265. vella, p. (1962): determining depths of new zealand tertiary seas.– tuatara, 10, 19–39. 2021 | 74/1 | 21–40 | 2 figs. | 6 pls. | 1 appendix | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction upper cretaceous and palaeogene deposits drilled in six deep exploration wells in the palmyrides, syria comprise an approximately 1300 metre thick succession of marine strata. these deposits are predominantly composed of hemipelagic argillaceous limestones and marls (upper cretaceous), deep water clayey limestones and marls (palaeocene and eocene), and sandstone, bioclastic limestone and marls (oligocene). their moderately to well preserved planktonic foraminiferal assemblages enable biostratigraphic determination. calcitic planktonic foraminiferal tests provide a valuable record of their natural habitats in ancient seas and oceans, and geochemical analyses allow determination of their ecological niche position within the water column (schackleton et al., 1985; pearson et al., 1993; pearson et al., 2001; edgar et al., 2010; birch et al., 2012). morphological characteristics of the tests (shape and size, wall texture, etc.) are usually developed as a response to the biotic and abiotic requirements of planktonic foraminiferal biostratigraphy and lithology of the upper cretaceous (upper campanian-maastrichtian) and palaeogene succession of the palmyrides (syria) vlasta premec fućek1,*, morana hernitz kučenjak2 and gabrijela pecimotika2 1 krvarić 36/1, 10 090 zagreb; (*corresponding author: vlasta.pfucek@gmail.com) 2 ina industrija nafte d.d., lovinčićeva 4, 10 000 zagreb, croatia doi: 10.4154/gc.2021.05 abstract an upper campanian to upper oligocene stratigraphic succession has been examined from six deep exploration wells in the palmyrides area of syria. most of the sedimentary succession contains rich and well to moderately preserved planktonic foraminiferal assemblages that enable successful age determination. the upper campanian and maastrichtian planktonic fauna is highly diverse with domination of warm water taxa such as globotruncana aegyptiaca, gansse­ rina gansseri, globotruncanella havanensis, globotruncanita angulata and pseudotextularia ele­ gans. the most dramatic turnover occurred across the cretaceous/palaeocene boundary when most planktonic foraminiferal species became extinct. the oldest palaeocene planktonic foraminiferal assemblage, rich in the number of specimens, but not very diverse, includes the following species: eoglobigerina eobulloides, globanomalina archeocompressa, chiloguembelina morsei, woodringina claytonensis and parasubbotina pseudobulloides. the late palaeocene is marked by origination of the morozovellids, acarininids and globanomalinids, while the early eocene is characterized by a tropical assemblage, dominated by muricate species, and by intensive speciation of acarinina and subbotina in the latest part. most of these species continue into the middle eocene and become a significant component of the planktonic community. the middle eocene is characterized by intensive speciation and domination of warm water genera such as acarinina, morozovelloides, and to a lesser degree turborotalia, globigerinatheka and hantkenina. the middle/late eocene boundary is marked by double extinction of the last muricate taxa acarinina mcgowrani and morozovelloides crasssatus, which indicate a variable climate, water column instability, and loss of surface habitats. in contrast, turborotalia and globi­ gerinateheka become more important in the late eocene. the eocene/oligocene boundary is marked by the extinction of most warm water taxa including turborotalia cerroazulensis group, hantkenina, globigerinatheka and some subbotinids. the beginning of the early oligocene is indicated by the domination of cool water taxa such as dentoglobigerina, globorotaloides, tenu­ itella and chiloguembelina. speciation of the spinose surface dweller ciperoella ciperoensis group reflects warming in the late oligocene. the combined observations of lithology with the diversity and composition of planktonic foraminifera assemblages indicate that the palmyrides area in syria was a tethyan bioprovince with a tropical to subtropical climate from the late campanian to the end of the eocene with deposition in deep sea environments (upper bathyal to outer shelf). in contrast, oligocene deposits and their microfossil content suggest temperate to warm climate conditions and sedimentation in middle to inner shelf environments. their natural habitats. these characteristics allow differentiation of four main upper ocean (i.e., photic zone) habitats: surface/subsurface, mixed-layers, thermocline and subthermocline. this study documents the composition, changes and frequency of the main planktonic foraminiferal groups during the geological time period spanning the late campanian to the end of the oligocene. here, the lithological characteristics and depositional environments of the upper cretaceous to palaeogene strata were determined, together with their correlation within the investigated palmyrides area of syria. previous biostratigraphic investigations of the upper cretaceous and palaeogene deposits from deep exploration wells in the palmyride area were conducted by lučić (2001), stanković et al. (2003; 2005), dacer et al. (2007), hernitz kučenjak et al. (2005, 2006), hernitz kučenjak (2008) and pecimotika et al. (2014). important biostratigraphic work on the palaeogene deposits in syria has been undertaken by krasheninnikov et al. (1996). article history: manuscript received may 07, 2020 revised manuscript accepted february 03, 2021 available online february 28, 2021 keywords: biostratigraphy, lithology, upper cretaceous, palaeogene, planktonic foraminifera, syria g eo lo gi a c ro at ic a geologia croatica 74/122 2. material and methods the biostratigraphic, lithological and palaeoecological results were obtained from drill cuttings collected from six exploration wells (numbered j-1 to j-6), and from two cored intervals in the j-3 well (842.5‒852 m and 1604‒1613 m). samples were collected every 10 to 20 m and a total of 453 samples were processed and analysed. sample preparation methods for micropalaeontological analyses varied according to the degree of lithification. loose rock samples were prepared by a standard washing procedure that included soaking in water with a small amount of 10‒15% hydrogen peroxide (h2o2), and washing after 24 hours under running water through 63 μm, 125 μm, 160 μm, 250 μm, 315 μm, and 630 μm sieves. these fractions were dried, and foraminifera were picked onto micropalaeontological slides. standard micropalaeontological analyses were performed by a stereomicroscope. scanning electron microscope (sem) was used for a detailed study of planktonic foraminiferal morphology (e.g., wall texture, ornamentation). petrographic thin-sections were also made from lithified rock samples. biostratigraphic interpretations were based on berggren & pearson (2005), and wade et al. (2011) for the palaeogene, and on robaszynski et al. (1984), caron (1985), robaszynski & caron (1995), premoli silva & sliter (1995, 1999) and premoli silva & verga (2004) for the upper cretaceous. determination of palaeogene planktonic foraminiferal genera and species was based on spezzaferri (1994), olsson et al. (1999), iaccarino et al. (2005), premoli silva & petrizzio (2006), pearson et al. (2006) and wade et al. (2018). the micropalaeontological investigation of the campanian and maastrichtian planktonic foraminiferal genera and species was focused on the vertical distribution, diversity and composition of mainly planktonic and less abundant benthic foraminiferal assemblages according to gawor-biedowa (1984), loeblich & tappan (1988), ismail (1992), bolli et al. (1994), ly & kuhnt (1994), kaiho (1998), premoli silva & verga (2004), ismail et al. (2007), and gasiński & uchman (2009), sari (2006, 2009), petrizzo et al. (2011) and pérez-rodríguez et al. (2012). genera and species of benthic foraminifera were also determined and counted for the calculation of plankton/benthos ratios (van der zwaan et al., 1990; murray, 1991). petrographic and sedimentological analyses focused on thinsections of rock samples taken every 10 to 20 m. the lithological column for each well is shown in figure 2. carbonate rocks were classified according to flügel (2010) and other rock types were classified using schemes published in pettijohn (1975). palaeoenvironmental interpretations were based upon the lithological and sedimentological analyses as well as the determined microfossil assemblages. 3. geological setting syria is located within the arabian plate (fig. 1), and almost completely surrounded by active plate boundaries. syria’s western boundary is marked by the dead sea fault system, which separates the arabian plate from the levantine subplate. to the north is the bitlis edge that represents the collision boundary between the arabian and eurasian plates. the zagros fault system is situated to the east and southeast and it marks the collision boundary between the arabian plate and iran (brew, 2001; brew et al., 2001). tectonically, syria can be divided into four major domains: 1) the palmyride fold and thrust belt; 2) the abd el aziz – sinjar uplift; 3) the euphrates graben or depression; and 4) the dead sea fault system (litak et al., 1998; brew, 2001; brew et al., 2001). the studied wells are located within the hayan exploration block (fig. 1), which is part of the palmyride area in the figure 1. map of syria showing the main tectonic zones (modified from brew, 2001). dark gray square indicates the location of the hayan exploration block in ne palmyrides, limited by the jihar fault and bilas block to the north, by the al daww depression to the se, the sw palmyrides to the south, and by the homs depression to the nw. the red point signifies the location of the j–1 to j–6 wells. g eologia c roatica premec fućek et al.: planktonic foraminiferal biostratigraphy and lithology of the upper cretaceous (upper campanian-maastrichtian) ... 23 central part of syria. the palmyrides are the most extensive and topographically prominent tectonic zone in syria. this area represents a 400 km long and 100 km wide intracontinental fold and thrust belt, extending from the dead sea fault zone in the west to the euphrates fault system in the east (lučić & foršek, 2000; brew, 2001). it is formed in between the two relatively undeformed tectonic blocks known as the allepo plateau to the north and the ruthbah uplift to the south. based on topography and structure, the palmyrides are commonly subdivided into the sw or frontal palmyrides and the ne or central palmyrides separated by the jihar fault (brew, 2001). the southwestern palmyrides are represented by a fold and thrust belt, whereas the northeastern palmyrides include the bilas and bishri blocks. the low-relief al daww depression, which is a 100 km long and 20 km wide inter-montaine basin, lies between the jihar fault and the short-wavelength folds of the southern palmyrides (lučić & foršek, 2000; brew, 2001; lučić et al., 2002; tomljenović et al., 2008). the hayan block is situated partly in the al daww depression and extends towards the bilas block. geophysical anomalies, identified both beneath and around the palmyrides, indicate that during the palaeozoic, mesozoic and part of the cenozoic this area was a tectonically unstable depocentre with 11 km thick deposits (mouty & al-maleh, 1983; chaimov et al., 1992; brew et al., 2001; križ et al., 2005; tomljenović et al., 2008). 4. lithology this investigation follows the lithostratigraphic distribution proposed by brew (2001). the examined succession spans the campanian to oligocene time interval and is represented by four lithostratigraphic units – the shiranish formation (upper campanian‒maastrichtian), kermav formation (palaeocene), jaddala formation (eocene) and chilou formation (oligocene). 4.1. shiranish formation (upper campanian–maastrictian) the shiranish formation (fig. 2) is characterized by argillaceous limestones, marls, chert and sporadic disc shaped or ovoid calcareous concretions (approx. 10‒30 cm in diameter). argillaceous limestone (mudstone/wackestone) and marls are composed of a clayey–microcrystalline calcitic matrix with abundant pelagic fauna. the abundance of planktonic foraminifera and the large amount of clayey detritus (sourced from the hinterland) evidently indicate an open-sea influence. accordingly, these sediments were deposited in upper bathyal to outer shelf environments. 4.2. kermav formation (palaeocene) the palaeocene deposits (fig. 2) are composed of clayey limestones and marls with pelagic fauna. clayey limestones and marls are generally grey in colour and may occasionally be yellowish or greenish, or locally dark grey. they are composed of micrite with variable amounts of clay and planktonic foraminifera. the lowermost palaeocene deposits consist of fossiliferous marl with phosphate grains, yellow or light brown in colour, present in the cored interval of the j-3 well (core-2, 1604‒1613 m). the only lithological differences relative to the underlying cretaceous deposits (shiranish formation) are the greater amount of clayey components and the different microfossil assemblage. the lithological characfigure 2. a schematic stratigraphic profile of the j-1 to j-6 wells. cored intervals belong to j-3 well, core-1 (842.5–852.0 m), middle eocene; core-2 (1604–1613 m), upper palaeocene. samples of the rock material from drill cuttings were taken every 10 to 20 metres. the lowest (lo) and the highest occurrences (ho) of the selected planktonic foraminiferal species are marked. g eo lo gi a c ro at ic a geologia croatica 74/124 teristics of these deposits, as well as their microfossil association dominated by planktonic species (over 95%) indicate deposition in deep sea environments (outer shelf to upper bathyal). 4.3. jaddala formation (eocene) the upper eocene deposits (fig. 2) are composed of two different facies. the lower facies is represented by chalky marl, which is in places very rich in glauconite, while the upper part is generally calcareous. the amount of glauconite locally increases high enough to form a horizon of glauconitic sands and glauconitic marl. the lower and middle eocene deposits are generally represented by limestones, calcitic marls and clayey limestones with a chalky appearance. chert is present in the lower part of these deposits as lenses, nodules and tabular beds. clayey limestones/ chalky limestones are light grey to brownish-white mudstone/ wackestone types with a variable amount of clayey components. planktonic and rare small benthic foraminifera are irregularly distributed within their micritic matrix. these limestones locally contain fine dispersed rounded to subrounded glauconite grains. marls are grey to brownish grey in colour and in places slightly silty with planktonic foraminifera. cherts are composed of very fine granular quartz with patches of chalcedony, which mostly have circular sections and resulted from infilling of the chambers of planktonic foraminifera or sponge spicules. in places, the siliceous matrix contains thin inclusions of micrite and microsparite in the shape of isolated crystals or fine aggregation of crystals with irregular edges marking the silicification front. glauconite grains are well-sorted with rounded to sub-rounded edges, mostly fine to medium sand-sized particles, and some have microscopic fissures. most of the glauconite grains have a homogenous and finely crystalline texture. surrounding the glauconite grains is a mainly micritic or clayey micritic matrix with some ferruginous oxide spots. lithological characteristics of these deposits, as well as their microfossil association with the domination of planktonic species indicate deposition in deeper sea environments (outer shelf to deep marine). 4.4. chilou formation (oligocene) the oligocene deposits (fig. 2) are represented by sandstone and conglomeratic sandstone with intercalations of sandy limestones or bioclastic limestones, which are yellow in colour, rich in large foraminifera, and alternating with marl and/or bioturbated limestone. sandstones are grey to brownish red, finemedium grained quartz arenite with subangular quartz grains in haematite and ferrous dolomite and, sporadically, calcite cement. conglomeratic sandstones are composed of subrounded quartz grains in dolomite (mostly ferrous) cement. limestones are light grey to yellowish in colour, mainly represented by homogenous or horizontally bioturbated mudstone/wackestone and rare sandy packestone, sporadically with fossil grains of mainly benthonic foraminifera and rare planktonic foraminifera or echinoids. in places, bioturbated limestones contain mud-balls, reaching 20‒30 cm in diameter. planktonic foraminifera are commonly pyritized. all types of limestones commonly contain nodules of different forms of chert as well as some detrital quartz arenite grains. marls are yellowish, light grey to dark grey in colour, partly silty or sandy, and commonly contain pyrite. moderately diverse microfossil associations of both planktonic and benthic foraminiferal species suggest temperate climate conditions. plankton/benthos ratio and lithofacies characteristics indicate sedimentation in middle to inner shelf environments. 5. biostratigraphy this micropalaeontological study covers a time period of over 50 million years (berggren et al., 1995; cohen et al., 2013; wade et al., 2011) with a sedimentary succession over 1300 m thick s (fig. 2). planktonic foraminiferal assemblages had changed during that time in the number of species, number of individuals, and test preservation. the micropalaeontological investigation of upper cretaceous and palaeogene microfauna was focused on the vertical distribution, diversity, and composition of mainly planktonic and less abundant benthic foraminiferal assemblages. genera and species of benthic foraminifera were also determined and counted for the calculation of plankton/benthos ratios after van der zwaan et al., 1990; murray, 1991. the boundary between palaeogene stratigraphic units was based on berggren & pearson (2005) and wade et al. (2011). 5.1. late campanian–maastrichtian identification of late cretaceous specimens is based on microscopic observations of thin-sections. studied material contains well preserved and diverse associations of foraminifera, especially in the j-5 and j-6 wells (fig. 2). these include highly diverse globotruncanids, rugoglobigerinids, globigerinelloids and heterohelicid planktonic foraminifera with rare small calcareous benthic foraminifera, and some inoceramids and echinoids. this assemblage is composed of the following representatives: contusotruncana contusa, racemiguembelina fructicosa, pseudotextularia elegans, globotruncanita conica, gansserina gansseri (pl. 1, fig. 1), plummerita hantkeninoides, globotrun­ canella pschadae, globotruncanita angulata, globotruncanita conica (pl. 1, fig. 2), rugoglobigerina macrocephala, globotrun­ cana aegyptiaca (pl. 1, fig. 3), globotruncana arca (pl. 1, fig. 4), globotruncana ventricosa (pl. 1, fig. 5), globotruncanella havanensis (pl. 1, fig. 6), globotruncanita stuarti and goglobige­ rinelloides alvarezi. according to hardenbol et al. (1998), the age of this unit is late campanian to maastrichtian. this assemblage also contains the following species with a wider stratigraphic range: muricohedbergella monmouthensis, glo­ botruncana insignis, globotruncana rosetta, rugoglobigerina rugosa (pl. 1, fig. 7), globotruncana bulloides (pl. 1, fig. 8), macroglobigerinelloides prairiehillensis (pl.1, fig 9), macroglobige­ rinelloides bolli (pl. 1, fig. 10), muricohedbergella holmdelensis (pl. 1, fig. 11), muricohedbergella monmouthensis (pl. 1, fig. 12), heterohelix globulosa (pl. 1, fig. 13), heterohelix striata, archaeo­ globigerina blowi (pl. 1, fig. 14), contusotruncana fornicata, glo­ bigerinelloides bollii and pseudotextularia elegans (pl. 1, fig. 15) and planoglobulina sp. the assemblage of small benthic foraminifera includes oridorsalis umbonatus, cibicidoides sp., bolivinoides sp., pullenia sp., tritaxia sp. and gavelinella sp. such a planktonic foraminiferal assemblage with diverse keeled taxa is characteristic for the tethyan warm water bioprovince. the high percentage (90‒95%) of planktonic taxa within the microfaunal assemblage suggests an upper to middle bathyal depth for this interval (boersma, 1988; murray, 1991; gräfe, 2005). the high diversity of planktonic foraminifera abruptly decreases in the uppermost part of this unit in all six wells. 5.2. early palaeocene the cretaceous/palaeocene boundary is marked by the extinction of most of the cretaceous planktonic foraminifera (olsson et al., 1999; wade et al., 2011). the lower palaeocene deposits, g eologia c roatica premec fućek et al.: planktonic foraminiferal biostratigraphy and lithology of the upper cretaceous (upper campanian-maastrichtian) ... 25 composed of clayey limestones and dark gray marls, contain rare, recrystallized specimens of planktonic foraminifera. therefore, in all the investigated wells the lowermost palaeocene is an almost sterile interval. there are only two exceptions with well preserved microfauna. samples collected in 1700‒1710 m interval in the j-2 well contains the oldest palaeocene planktonic foraminiferal association, rich in the number of specimens, but not very diverse. an almost identical planktonic community is determined from the cored interval (1604‒1613 m) in the j-3 well, where fossiliferous marls contain abundant planktonic foraminifera characteristic most probably of the lowermost palaeocene zones p0‒pα after olsson et al. (1999) and wade et al. (2011). this association contains the following taxa: eoglobigerina eo­ bulloides (pl. 2, fig. 1), e. edita, parasubbotina pseudobulloides (pl. 2, fig. 2), woodringerina claytonensis (pl. 2, fig. 3), chi­ loguembelina morsei, globanomalina archeocompressa and subbotina trivialis. in addition, sample 1540‒1545 m in j-3 well contain also subbotina triloculinoides (pl. 2, figs. 4 and 5) and chiloguembelina morsei (pl. 2, fig. 6). in the middle and upper part of the lower palaeocene interval, a more diverse planktonic foraminiferal assemblage has been determined: globanomalina compressa, praemurica pseudoin­ constans, praemurica inconstans, subbotina triloculinoides and s. triangularis. some of the recognized species, such as globanomalina imitata, g. ehrenbergi, morozovella praeangu­ lata, parasubbotina pseudobulloides and chiloguembelina mid­ wayensis first appeared in the early palaeocene and continue into the late palaeocene. the species morozovella praeangulata (pl. 2, fig. 7) is the first representative of an important palaeocene genus that had its lowest occurrence (lo) in the uppermost part of this interval. biserial genus chiloguembelina is present in the entire interval and the genera praemurica and globanoma­ lina are common in the upper part of this interval. based on the planktonic foraminiferal assemblage, this interval approximately corresponds to the early palaeocene zones p1 to p2 after wade et all. (2011). although planktonic foraminifera dominate in the assemblage (90%), some smaller benthic genera are also present: neoeponides, pullenia, tritaxia, dorothia and stilostomella. 5.3. late palaeocene the upper palaeocene deposits, present in all investigated wells, contain rich, highly diverse and moderately to very well preserved planktonic foraminiferal assemblages. the boundary between the lower and upper palaeocene is defined by the lowest occurrence (lo) of igorina pusilla and morozovella angulata (olsson et al., 1999). species which continue from the early palaeocene and became extinct in the late palaeocene include subbotina triangularis, subbotina triloculinoides, morozovella praeangulata, parasubbotina pseudobulloides and praemurica inconstans. the main characteristic of the upper palaeocene planktonic assemblage is the domination of warm water species with complex test morphology (ornamented taxa), including mo­ rozovella acuta, m. velascoensis, m. angulata (pl. 2, fig. 8 and 9), m. praeangulata, acarinina mckannai, igorina pusilla (pl. 2, fig. 10), i. tadjikistanensis and i. albeari. however, species with a thin and smooth wall texture such as globanomalina chapmani and globanomalina pseudomenardii are present with a few specimens each. subbotina cancellata (pl. 2, fig. 11), subbotina cf. triangularis (pl. 2, fig. 12) and s. triloculinoides are common. furthermore, species that have their first appearance in this interval and cross the palaeocene/eocene boundary include mo­ rozovella aequa, m. subbotinae, subbotina velascoensis, acarin­ ina coalingensis (pl. 2, fig. 13), a. soldadoensis (pl. 2, fig. 14) and acarinina sp. (pl. 2, fig. 15). microperforate biserial species are represented by chiloguembelina midwayensis, c. wilcoxen­ sis, c. crinita and zeauvigerina waiparaensis. the rich and highly diversified assemblage indicates the biostratigraphic interval from zone p3 to zone p5 after wade et al. (2011). benthic foraminifera appear with a small number of individuals per sample. the plankton/benthos ratio is approximately 90:10, indicating deep and open marine depositional environments. 5.4. early eocene the palaeocene/eocene boundary is marked by the lowest occurrence (lo) of acarinina sibaiyaensis (berggren and pearson, 2005; wade et al., 2011). the material studied contains rich and well preserved planktonic foraminiferal assemblages. pseudohastigerina wilcoxensis has its first appearance in the lowermost part of the lower eocene and indicates the beginning of zone e1. the lower part of the interval which most probably corresponds to zones e1 to e3, is dominated by tropical warm water taxa such as acarinina, mo­ rozovella and igorina. many of the species recognized in this interval, which appeared in the late palaeocene, continued into the early eocene such as morozovella subbotinae (pl. 3, fig. 1), mo­ rozovellaa aequa (pl. 3, fig. 2), morozovella acuta, acarinina coalingensis, acarinina soldadoensis, subbotina velascoensis, globanomalina planoconica (pl. 3, fig. 4) and chiloguembelina wilcoxensis. species that first occurred in the middle part of the early eocene (approximately correspond to the e4 to e6 zones, wade et al., 2011), and continued into the middle eocene are; morozovella aragonensis, morozovella crater, acarinina primitiva, acarinina pentacamerata (pl. 3, fig. 3), igorina broedermani (pl. 3, fig. 5), and acarinina cuneicamerata (pl. 3, fig. 6). in addition, morozo­ vella formosa, acarinina pseudotopilensis and acarinina quetra are present with a few specimens. the uppermost part of the lower eocene interval which approximately corresponds to zone e7 (wade et al., 2011), is characterized by the first occurrence (fo) of several new species and genera and some of them will become important constituents of the middle eocene fauna. also significant is the speciation of the genus acarinina, which is represented by the following species: acarinina bullbrooki (pl. 3, fig. 7), a. mcgowrani, and a. praetopilensis. the first appearance of turborotalia frontosa, (pl. 3, fig. 8), parasubbotina griffinae, subbotina yeguaensis, s. eocaena (pl. 3, figs. 9 and 10), s. linaperta (pl. 3, fig. 11), and subotina sp. (pl. 3, fig. 12) have been observed in this interval and all these species continue into the middle eocene. small benthic foraminifera comprise only 10% of the total assemblage. 5.5. middle eocene the base of the middle eocene is defined by the lowest occurrence (lo) of guembelitriodes nuttally (berggren & pearson, 2005; wade et al., 2011). in addition, the lowermost part of the middle eocene is characterized by the common occurrence of acarinina bullbrooki. the planktonic foraminiferal assemblage of the interval, which roughly corresponds to the zone e8 after wade et al. (2011), is dominated by acarininids, represented by acarinina pentacamerata, a. cuneicamerata, a. praetopilensis and a. primi­ tiva. acarininids together with other muricate taxa (morozovella, g eo lo gi a c ro at ic a geologia croatica 74/126 igorina and rare morozovelloides) comprise up to 45‒50% of the total foraminiferal assemblage. subbotinids are also common (20%) and include the following species: subbotina eocaena, s. yeguaensis, s. linaperta, s. crociapertura and s. senni. turborotalids are represented only by turborotalia frontosa. other species present include: parasubbotina griffinae, praemurica lozanoi, globanomalina australiformis and catapsydrax unica­ vus. specimens of the genera hantkenina (h. dumblei, pl. 4, fig. 1) and globigerinatheka represented with the species g. curry (pl. 4, fig. 2) and g. subconglobata (pl. 4, fig. 3) are rare in this interval. the first representatives of the new eocene genus mo­ rozovelloides occur with only a few specimens of m. bandy (pl. 6, fig. 4) per sample. pseudohastigerina micra and p. wilcoxen­ sis are the dominant species in the small size fraction (<125 μm) and make up to 40% of the small taxa. beside them planorotalites pseudoscitula, acarinina collactea and the biserial form chiloguembelina crinita are also present. deposits from the middle part of the middle eocene (approximately correspond to zones e10, e11 and e12) contain very rich and highly diverse planktonic foraminiferal assemblages, typi cal of low latitude areas. acarininids remain a dominant component and are represented by acarinina mcgowrani (pl. 4, fig. 5), a. praetopilensis, a. rohri, and a. topilensis (pl. 4, fig. 6). after the extinction of the two last representatives of morozovella (m. aragonensis and m. crater), the new middle eocene genus morozovelloides expanded in this interval. two new species mo­ rozovelloides crassatus (pl. 4, fig. 7) and m. coronatus become an important component of the planktonic community and together with acarininids made up to 45% of the total microfauna, whereas species morozovelloides lehneri (pl. 4, fig. 8) occurs rarely. subbotinids are still present with 20% of the total assemblage with the most common species s. eocaena (pl. 4, fig. 9) and s. lina­ perta (pl. 4, fig. 10). this tropical/subtropical fauna is also characterized by relatively rare (1‒2%) globigerinathekids as well as turborotalids (2‒3%) represented by turborotalia frontosa, t. possagnoensis, t. pomeroli (pl. 4, fig. 11) and t. cerroazulensis (pl. 4, fig. 12). besides planorotalites and pseudohastigerina, the small size fraction is enriched by common microperforate biserial taxa chiloguembelina ototara, chiloguembelina sp. and strep­ tochilus martini. the triserial species jenkinsina columbiana is present with a few specimens per sample. in the upper part of the middle eocene, which approximately corresponds to zones e13, muricate species significantly decrease in abundance. acarinina mcgowrani, morozovelloides crasatus and small acarininids made up to 20% of the total assemblage. they become replaced by an increasing number of turborotalids, subbotinids and globigerinatekids. in the latest middle eocene, species with cooler water preference such as subbo­ tina, dentoglobigerina, catapsydrax and turborotalita become an important component in the microfossil assemblage. the latest middle eocene is marked by the rare occurrence of the last large muricate representatives acarinina mcgowrani and morozovel­ loides crasatus and by their extinction at the middle/late eocene boundary. the percentage of planktonic foraminifera in the middle eocene deposits varies between 90 and 95%. 5.6. late eocene the middle/upper eocene boundary is marked by the double extinction of the last large muricate representatives acarinina mcgowrani and morozovelloides crassatus (wade, 2004; wade et al., 2012). small acarinids represented by a meddizai, a. colactea and a. echinata continue into the late eocene. based on the planktonic foraminiferal association standard biozonation from zones e14 to e16 after wade et al., (2011) have been recognized in the late eocene interval (hernitz kucenjak et al., 2006). planktonic foraminifera show significant changes in comparison with the middle eocene assemblage. turborotalids, which intensively diverse during the middle eocene, become a more important component of the upper eocene planktonic community and they are represented by turborotalia pomeroli, t. cerroazulensis (pl. 5, fig. 1), t cocoaensis (pl. 5, figs. 2 and 3) and t. increbescens. species turborotalia ampliapertura (pl. 5, fig. 4) occurred in the upper part of this interval which corresponds to zone e15. the last species of this lineage turborotalia cunialensis (pl. 5, fig. 5) appeared in the latest eocene with very few specimens and indicates zone e16 (wade et al., 2011). globigerinathekids was a successful group in the lower part of the late eocene zone e14 and comprised up to 5% of the total fauna. they are represented by globigerinatheka barry (pl. 5, fig. 6), g. kugleri, g. luterbacheri and g. index. they reduced in both diversity and number and only a few specimens of g. index are present in the middle part of this interval (zone e15). hantkeninids are represented by rare occurrences of hantkenina alaba­ mensis (pl. 5, fig. 7), h. nanggulanensis and cribrohantkenina inflata. subbotinids are still present with 20‒25% of the assemblage and include subbotina linaperta (pl. 5, fig. 8), s. utilisin­ dex, s. corpulenta, s. eocaena and s. yeguaensis (pl. 5, fig. 9). during the late eocene, dentoglobigerinids become more frequent, represented by the species dentoglobigerina galavisi (pl. 5, fig. 10), and d. tripartita, whereas d. pseudovenezuelana occur sporadically. small sized species globoturborotalita martini and g. ouachitaensis (pl. 5, fig. 11) are also present at 3‒4% of the planktonic assemblage. the microperforate biserial forms are represented by streptochilus martini and chiloguembelina oto­ tara, which persisted from the middle eocene, while chiloguem­ belina cubensis first appeared before the eocene/oligocene boundary (zone e16). during the late eocene small acarinids become very rare and are observed only in the small size fraction (<125 μm). pseudohastigerinids are represented by p. micra (pl. 5, fig. 12) and p. naguawichensis (125‒160 μm fraction). benthic foraminifera increase in abundance during the late eocene and vary between 35 and 40%, indicating shallowing of the depositional realm. 5.7. early oligocene the eocene/oligocene (e/o) boundary is marked by the extinction of all hantkeninids and the last representative of the genus globigerinatheka g. tropicalis. planktonic foraminiferal zones from o1 to o4 have been recognized (berggren & pearson, 2005; wade et al., 2011, 2018; hernitz kucenjak et al., 2006). the eocene/oligocene boundary represents a significant faunal overturn. most of the specialized warm water taxa such as the turborotalia cerroazulensis group, globigerinathekids and hantkeninids, which were important constituents of the middle and late eocene planktonic foraminiferal community were replaced by cool water taxa such as dentoglobigerina, cata­ psydrax, globorotaloides, tenuitella and chiloguembelina (keller, 1983; boersma & premoli silva, 1991; hernitz kucenjak et al., 2006). at the end of the late eocene, just before the e/o boundary, chiloguembelina cubensis (pl. 6, fig. 11) appeared, whereas cassigerinella chipolensis (pl. 6, fig. 1) occurred immediately after the e/o boundary in zone o1. the earliest oligocene planktonic foraminiferal assemblage in zones o1 and o2 comprises warm to temperate-water taxa ing eologia c roatica premec fućek et al.: planktonic foraminiferal biostratigraphy and lithology of the upper cretaceous (upper campanian-maastrichtian) ... 27 cluding dentoglobigerina tripartita (pl. 6, fig. 2), d. pseudovene­ zuelana, d. tapuriensis (pl. 6, fig. 3), subbotina gortanii, s. corpulenta, s. utilisindex, s. angiporoides, turborotalia amplia­ pertura (pl. 6, fig. 4) and t. increbescens. small sized species such as pseudohastigeina naguewichiensis (pl. 6, fig. 5), tenu­ itella gemma, tenuitella sp., globigerina officinalis (pl. 6, fig. 6) are also common. small sized biserial taxa such as chiloguem­ belina ototara (pl. 6, fig. 7), c. andreae, and streptochilus mar­ tini are present only in the lower part of the early oligocene (zones o1 and o2), whereas chiloguembelina cubensis (pl. 6, fig 8) and c. adriatica (pl. 6, fig. 9) occurred in the whole interval up to zone o4. in the upper part of the early oligocene which corresponds to zones o3 and o4, the planktonic foraminiferal association is somewhat different – the number of large globigerinids (dento­ globigerina, subbotina) is reduced, but the share of smaller, spinose forms such as specimens of ciperoella group, ciperoella anguliofficinalis (pl. 6, fig. 10); c. angulisuturalis (pl. 6, fig. 11), and c. ciperoensis (pl. 6, fig. 12) gradually increased. the number of benthic foraminiferal taxa gradually increased towards the end of early oligocene, and the plankton/ benthos ratio is 50:50. 5.8. late oligocene the boundary between the early and late oligocene is marked by the highest common occurrence (hco) of chiloguembelina cubensis (berggren et al., 1995; wade et al., 2011; 2018), with the proportion of this species in the community of planktonic foraminifera from the smallest sieved fraction (125‒63 mm) exceeding 5% (hernitz kucenjak et al., 2014; premec fućek et al., 2018). the lower part of the late oligocene which corresponds to zones o5 and o6 is characterized by large numbers of specimens of the genera ciperoella (c. angulisuturalis, c. ciperoensis, c. anguliofficinalis), and globoturborotalita (g. ouachitaensis, g. occlusa). the top of zone o5 is marked by the last occurrence of paragloborotalia opima. during zones o6 and o7 small size taxa are observed, including: cassigerinella chi­ polensis, tenuitella angustiumbilicata, streptohilus pristinum, and rare specimens of chiloguembelina cubensis and jenkinsina columbiana. in the uppermost part of the late oligocene (zone o7) the first appearance of the trilobatus primordius has been observed. the boundary between the oligocene and the miocene is defined by the first occurrence of globorotalia kugleri (berggren et al., 1995; berggren & pearson, 2005, wade et al., 2011; 2018). this planktonic foraminiferal species has not been observed in samples from the exploration wells examined here. however, in the latest oligocene, close to the miocene boundary, a large number of cassigerinela chipolensis specimens occurred in the planktonic foraminiferal association. this occurrence as well as the composition of the entire planktonic foraminiferal association was used to place the oligocene/miocene boundary. the upper oligocene benthic foraminiferal assemblage significantly increases both in diversity and in the number of specimens with plankton/benthos ratio of 30:70%. 6. discussion the studied succession encompasses a long geological period from the upper campanian to the end of the palaeogene, which is characterized by global changes in ocean circulation and general cooling climatic trends (haq et al., 1987; hardenbol et al., 1998; zachos, 2001; mackensen, 2004; miller et al., 1987, 2008;). the late cretaceous was characterized by low latitudinal thermal gradients (huber et al., 1995), and the formation of deep warm, saline bottom waters (thermospheric circulation; haq, 1981; almogi-labin et al. 1993; widmark & speijer, 1997). in contrast, the palaeogene was characterized by general climatic cooling, which led to more pronounced latitudinal thermal gradients and changes in ocean circulation (thermohaline circulation; haq, 1981). climatic changes in conjunction with global sea level f luctuation significantly affected planktonic foraminiferal populations in the late cretaceous and palaeogene in all word oceans (haq, 1981; haq et al., 1987; miller et al., 2008; katz et al., 2008). most of the deposits examined here contain rich and well-preserved foraminiferal assemblages, which help in palaeoceanographic and palaeoclimatic interpretations of the investigated area. 6.1. late cretaceous planktonic foraminiferal assemblages late cretaceous sediments contain rich and highly diverse foraminiferal assemblages which imply a well-stratified water column and warm surface water. the presence of ornamented and double-keeled globotruncanids which belong to highly specialized (k-strategist) genera indicate a long and relative stable period with a tropical to subtropical climate. globotruncanids are usually regarded as intermediate to deep ocean dwellers and were geographically limited to the tethyan tropical-subtropical belt during the late cretaceous (abramovich et al., 2002, 2003; petrizzo, 2002). planktonic foraminiferal species from the upper campanian to maastrichtian interval inhabited a different niche in the stratified water column (abramovich et al., 2003; huber et al., 1995; petrizzo, 2002). deep-water habitats (subthermocline) were occupied by relatively few species globotruncanella havanensis, gan­ sserina gansseri and planoglobulina sp. the most stressful niche was the surface layer inhabited only by pseudoguembelina species (abramovic et al., 2003). most species such as globotruncana, contusotruncana, rugoglobigerina, pseudotextularia and hetero­ helix occupied subsurface depths of the mixed layer. the assemblages could also vary between the thermocline layer and the subsurface mixed layer during cool and warm intervals. during cool climate intervals, keeled globotruncanids and perhaps globigerinel­ loides and racemiguembelina occupied the thermocline layer, whereas rugoglobigerina, pseudotextularia and heterohelicids inhibited the subsurface mixed layer (abramovich et al., 2003). sedimentation during the late campanian and maastrichtian took place in pelagic environments (outer shelf to upper bathyal), as indicated by the high percentage of planktonic foraminifera (90‒95%) and the presence of complex morphotypes (k-strategists) dominant in open oceans (robaszynski and caron, 1995; abramovich et al., 2002, 2003). the high diversity of planktonic foraminifera abruptly decreases in the uppermost part of this unit indicating changes and possible cooling in the latest cretaceous ocean. 6.2. palaeogene planktonic foraminiferal assemblages at the cretaceous/palaeocene (k/pg) boundary, due to the catastrophic chicxulub impact event, the planktonic foraminiferal assemblage was reduced to a minimum, with only a few species surviving across the boundary (olsson et al., 1999; arenillas et al., 2006; macleod et al., 2007; koutsoukos, 2014). however, a number of new genera and species originated in the earliest palaeocene during a relative short period of about 60 kya (arenillas et al., 2006; wade et al, 2011; birch et g eo lo gi a c ro at ic a geologia croatica 74/128 al., 2012). although the cretaceous/palaeogene boundary is not documented in the studied intervals, the oldest palaeocene planktonic foraminiferal assemblage is documented in the j-2 well (sample 1700‒1710 m) and in the cored interval (1604‒1613 m) from the j-3 well. this early palaeocene planktonic community is rich in the number of specimens but is not very diverse. it includes eoglobigerina eobulloides (pl. 2, fig. 1), e. edita, globanomalina archeocompressa, chiloguembelina morsei (pl. 2, fig. 6), woodringina claytonensis (pl. 2, fig.3), subbotina trivialis and parasubbotina pseudobulloides (pl. 2, fig. 2), which likely belong to the earliest palaeocene zones p0‒pα. small species are represented by eoglobigerina eobulloides, which dominates the assemblage and is together with parasubbotina pseu­ dobulloides, the first palaeogene representative with a cancelate spinose wall texture (hemleben et al., 1991; olsson et al., 1999). these innovations enabled these small foraminifera to occupy the surface niche in the water column like recent planktonic species (hemleben et al., 1989). isotopic data by birch et al. (2012) suggest that these small early palaeocene species had a rapid evolution after the cretaceous/palaeogene (k/pg) mass extinction and inhabited a different niche in the thermally stratified water column. birch et al. (2012) also identified a metabolic disequilibrium in carbon isotopes, which indicated the possible photosymbiotic relationship between foraminifera and algal symbionts. these data indicated that a photosymbiotic relationship may have been important in the early palaeocene after the mass extinction. although most of the surviving foraminiferal species belong to an opportunistic (r-strategist) group of organisms, the empty niche in the tropical to subtropical oligotrophic oceans provided them with an opportunity to evolve a new, more specialistic mode of life such as morphological adaptation to inhabit the surface and subsurface niche in the water column due to the metabolic requirements of the symbiotic algae (bé, 1982; hemleben et al., 1991). consequently, the test morphology of the early palaeocene species, including the spinose wall texture of eoglobigerina and subbotina or smooth surface of globanoma­ lina, are closely related to their preferred niche in the water column (birch et al, 2012). the late palaeocene is characterized by intensive speciation of the muricate genera morozovella and acarinina, which dominate the assemblage. together with the genus igorina they form up to 50% of the assemblage. these species with ornamented tests live in the surface/subsurface layer of the photic zone because of the metabolic requirements of their symbionts (schackleton et al., 1985; d’hondt et al, 1994, norris, 1996; quillévéré & norris, 2003; birch et al., 2012). in addition, opportunistic (r-strategists) species subbotinids and globanomalinids, are also common inhabitants of the thermocline layers. a rich and highly diverse planktonic community indicates oligotrophic habitats, warm surface water, and a very well stratified water column with a stable thermocline. the diversity peaked in the upper part of the late palaeocene. the predominance of planktonic foraminifera suggests sedimentation in deeper open sea environments (outer shelf to upper bathyal). the latest palaeocene is assigned as a period of global warming (zachos et al., 2001; guasty & speijer, 2007). the boundary between the palaeocene and the lower eocene is marked by the extinction of several muricate species which was one of the most successful groups during the late palaeocene. the boundary interval is marked by a negative shift in δ13c values, i.e. the carbon isotope excursion (cie), alegret et al., 2006. this warm period, also known as the palaeocene-eocene thermal maximum (petm), is characterized by stressful conditions in the upper mixed layer which was inhabited by muricate planktonic foraminifera with a symbiotic mode of life. global warming that occurred during the petm possibly caused the loss of the algal photosymbionts, i.e. bleaching (alegret et al., 2006; luciani et al., 2017 a, b). a similar event connected with muricate species extinction (acarinina and morozovelloides) is documented in the upper middle eocene (wade, 2004; wade et al., 2012). in addition, an increase of primary production and eutrophication, and decrease in oxygen level may also be unfavourable elements in the upper mixed layer which led to the extinction of these k-mode strategists. the early eocene planktonic assemblage is also dominated by muricate warm-water taxa including acarinina, morozovella and igorina, which comprise approximately 40% of the planktonic foraminiferal fauna. muricate species which hosted algal photosymbionts and occupied the upper mixed layer, are the most important calcifiers during the early eocene (premoli silva & boersma, 1988; pearson et al., 2006; luciani et al., 2017 a, 2017 b). these low latitude assemblages are also characterized by the common subbotina (20%), globanomalina (3%) and chiloguembelina (3%) species. such domination of warm water taxa indicate a tropical climate, warm surface water and a well-stratified column inhabited by many muricate species. the well-stratified water column, however, provided many niches and supported the species that also prefer cooler sea water such as the subbotinids, parasubbotinids and globanomalinids which inhabited the thermocline layer. the upper part of the lower eocene is characterized by significant speciation of the genera subbotina, parasubbotina and acarinina and also the first appearance of the genus turborotalia. most of the planktonic species that originated in the latest early eocene continued into the middle eocene. the trend of speciation continued into the middle eocene when many new species originated (premoli silva & boersma, 1988; pearson et al., 2006). the speciation rate exceeded the extinction rate and resulted in the highest diversity of the plankton community during the palaeogene. these highly diverse planktonic foraminiferal assemblages are characterized by the dominance of specialized (k-mode life strategists) acarininids, morozovelloids, globigerinathekids, and by the common occurrence of the opportunistic species (r-mode life strategists) subbotinids, turborotalids and catapsydraxids (premoli silva & boersma, 1988). all these observations suggest the presence of an oligotrophic ocean with a well-stratified water column that hosted many groups of planktonic foraminifera with different habitat preferences (pearson et al., 1993; pearson et al., 2001). the ocean stratification was supported by a tropical to subtropical climate and stable thermocline (pearson et al., 2001). both a warm climate and the high intensity of sun light were also favourable for the symbiotic mode of life of the specialized forms with ornamented calcite tests such as acarinina and morozovelloides (wade, 2004). in the upper part of the middle eocene, the number of muricate species decreased in abundance, indicating cooling and the instability of the water column (sexton et al., 2006; premec fućek et al., 2010). the last representatives of the larger muricate taxa acarinina mcgavrani and morozovelloides crassatus had their highest occurrence (ho) at the middle/late eocene boundary (wade, 2004; premec fućek et al., 2010; wade et al., 2012). the cooling that began in the middle eocene significantly affected the late eocene planktonic foraminiferal community g eologia c roatica premec fućek et al.: planktonic foraminiferal biostratigraphy and lithology of the upper cretaceous (upper campanian-maastrichtian) ... 29 (cavelier et al., 1981; premoli silva & boersma, 1988; boersma & premoli silva, 1991; hallock et al., 1991; spezzaferri et al., 2002). this climatic change is associated with a shallowing of thermocline depth and increased delivery of nutrients to the surface waters (spezzaferri et al., 2002). these events caused a reduction in the abundance of shallow and warm water species of planktonic foraminifera (spezzaferri et al., 2002). micropalaeontological results obtained from the studied wells are in accordance with these general trends. during the late eocene, most changes in the planktonic foraminiferal assemblage were associated with the mixed layer and the upper part of the thermocline. hantkeninids, globigerinatekids and turborotalids declined in abundance and diversity during this time. at the same time, the deeper dwelling forms such as subbotina, dentoglobigerina, catapsydrax and globigerinoides proliferated. the cooling that started in the middle eocene reached its maximum around the eocene/oligocene boundary, and this climate transition is marked by a distinct change in the association of planktonic foraminifera (keller, 1983, boersma & premoli silva, 1991; zachos et al., 1996). warm water species including representatives of the genera hantkenina, cribrohant­ kenina and globigerinatheka, and most representatives of the genus turborotalia became extinct. the surface mixed layer thinned due to shallowing of the thermocline (spezzaferri et al., 2002), resulting in higher diversity of the deeper dwelling and cool water forms (e.g., genera dentoglobigerina, subbotina, catapsydrax). in addition, a size reduction in specimens of the genus pseudohastigerina at the eocene‒oligocene transition, indicated unfavourable environmental conditions. the lower part of the early oligocene is characterized by the predominance of the genera dentoglobigerina and subbotina. they inhabit the deeper part of the water column and do not have symbionts. instead, they feed on organic particles in the water column (hemleben et al., 1989), which indicates blooming of phytoplankton and upwelling. a large number of individuals of the opportunistic genera such as dentoglobigerina, subbotina and pseudohastigerina in the early oligocene indicates thermocline shallowing due to mixing of the water mass, which in turn is an indicator of reduced temperatures (boersma & premoli silva, 1991). towards the top of the early oligocene, there was a shift in the distribution of species within the available niches. this is reflected in an increase in the number of species in the mixed layer and the appearance of specimens of the small spinose symbiont bearing genera ciperoella (c. ciperoensis, c. angulisuturalis), which are indicators of warmer water temperatures and oligotrophy (spezzaferri et al., 2002). in the late oligocene an increase in the number of species of planktonic foraminifera was documented in all wells. this especially applies to the species that inhabit the mixed layer – glo­ boturborotalita ouachitaensis, g. occlusa, ciperoella angulisu­ turalis, c. ciperoensis, and globigerina officinalis. these spinose species are adapted to oligotrophic conditions (hallock et al., 1991; pearson, 1998; spezzaferri et al., 2002) and live in symbiotic relationships with photosynthetic algae, mostly dinoflagellates (hemleben et al., 1989). furthermore, the species trilobatus primordius had its first occurrence in the late oligocene and indicates warmer climatic conditions. at the same time, the number of deep dwelling species (dentoglobigerina, subbo­ tina, catapsydrax) that fed mostly on particulate organic matter was reduced. these observations suggest reduced primary production and oligotrophy, and gradual warming during the late oligocene (spezzaferri & premoli silva, 1991; spezzaferri et al., 2002). 8. conclusion this study focused on the rich, well-preserved and diverse planktonic foraminiferal assemblages found in upper cretaceous to upper oligocene deposits from exploration wells in the palmyrides area of syria. the upper cretaceous strata predominantly consist of hemipelagic argillaceous limestones and marls with abundant pelagic microfauna. palaeocene and eocene deep-water clayey limestones and marls with a high percentage of planktonic foraminifera (90%) indicate upper bathyal to outer shelf environments. in contrast, oligocene sandstone, bioclastic limestone and marls with an increasing percentage of benthic foraminifera (70%) indicate sedimentation in middle to inner shelf environments. global palaeoenvironmental changes are reflected in the composition, speciation and extinction of the examined planktonic foraminiferal population. the upper campanian and maastrichtian planktonic fauna is highly diversified with the domination of warm water taxa such as contusotruncana contusa, racemiguembelina fructicosa, globotruncana aegyptiaca, glo­ botruncana ventricose, gansserina gansseri, globotruncanella havanensis, globotruncanita angulata, globotruncanita stuarti, rugoglobigerina macrocephala, macroglobigerinelloides alvarezi and pseudotextularia elegans. the most dramatic change occurred at the cretaceous/palaeocene boundary when most planktonic foraminiferal species became extinct. the oldest documented palaeocene planktonic foraminiferal assemblage in the investigated wells includes eoglobigerina eobulloides, globano­ malina archeocompressa, chiloguembelina morsei, woodringina claytonensis and parasubbotina pseudobulloides. this assemblage is rich in the number of specimens but is not very diverse and indicates a relatively rapid recovery and occurrence of new species with novel abilities, such as spinose wall texture and possible photosymbiotic relationships with algae. the late palaeocene was characterized by the origination and domination of warm water taxa with complex test morphology such as morozovella and acarinina which imply a tropical to subtropical climate. the palaeocene/eocene boundary is assigned as a period of global warming known as the palaeocene-eocene thermal maximum (petm), characterized by stressful conditions in the upper mixed layer which was inhabited by muricate planktonic foraminifera with a symbiotic mode of life. even though the plankton were affected, most planktonic foraminiferal species successfully survived into the eocene and there were no major extinctions. similar palaeoclimatic and palaeoceanographic trends with the domination of the muricate species morozovella, acarinina and igorina which hosted algal photosymbionts and occupied the upper mixed layer continued into the early eocene. the upper part of the early eocene is characterized by significant speciation of the genera subbotina, parasubbotina and acarinina and also first appearance of the genus turborotalia. the middle eocene was characterized by intensive speciation and the domination of warm water genera such as morozo­ velloides, turborotalia, globigerinatheka and hantkenina. in contrast to mid latitudes, the three important genera turborota­ lia, globigerinatheka and hantkenina are present in low numbers in the investigated area. double extinction of the last muricate taxa acarinina mcgowrani and morozovelloides crasssatus ocg eo lo gi a c ro at ic a geologia croatica 74/130 curred at the middle/late eocene boundary and indicates a changeable climate and water column instability. the eocene/oligocene boundary is marked by the extinction of most warm water taxa including the turborotalia cerroazu­ lensis group, hantkenina, globigerinatheka and some subbotinids, in association with intensive short-term global cooling. the beginning of the oligocene is characterized by the domination of cool water taxa such as dentoglobigerina, globorotaloides, tenu­ itella and chiloguembelina. speciation of the spinoze surface dweller ciperoella ciperoensis group in the late oligocene is indicative of warming. the lithology, diversity and composition of the planktonic foraminiferal assemblages indicate that the palmyrides area in syria was a tethyan bioprovince with a tropical to subtropical climate from the late campanian to the end of the eocene, when deposition took place in deep open marine environments. in contrast, oligocene deposits and the microfossil content suggest temperate to warm climate and sedimentation in middle to inner shelf environments. acknowledgement the authors thank two anonymous reviewers for their useful comments and suggestions. we are grateful to bosiljka glumac for discussions and critical reading that improved the original text of the manuscript. we also thank ina-industrija nafte d.d. zagreb for providing samples for analysis and renata slavković for taking sem images. references abramovich, s. & keller, g. (2002): high stress late maastrichtian palaeoenvironment: inference from planktonic foraminifera in tunisia.– palaeogeography, palaeoclimatolology, palaeoecology, 178, 145–164. abramovich, s., keller, g., stüben, d. & berner, z. (2003): characterization of late campanian and maastrichtian planktonic foraminiferal depth habitats and vital activities based on stable isotopes.– palaeogeography, palaeoclimatolology, palaeoecology, 202, 1–29. doi: 10.1016/s0031-0182(03)00572-8 alegret, l., ortiz, s., arenillas, i. & molina, e. (2006): palaeoenvironmental turnover across the palaeocene/eocene boundary at the stratotype section in dababiya (egypt) based on benthic foraminifera.– terra nova, 17/6, 526–536. doi: 10.1111/j.1365-3121.2005.00645.x almogi-labin, a., bein, a. & sass, e. (1993): late cretaceous upwelling system along the southern tethys (israel): interrelationship between productivity, bottom water environmens, and organic matter preservation.– paleoceanography, 8, 671–690. doi: 10.1029/93pa02197 arenillas, i., arz, j.a., grajales-nishimura, j., murillo-muñeton, g., alvarez, w., camargo-zanoguera, a., molina, e. & rosalesdomínguez, c. (2006): chicxulub impact event is cretaceous/paleogene boundary in age: new micropaleontological evidence.– earth and planetary science letters, 249, 241‒257. doi: 10.1016/j.epsl.2006.07.020 bé, a.w.h. (1982): biology of planktonic foraminifera.– in: buzas, m.a. & sen gupta, b.k. (eds.): notes for a short course, 219.– university of tennessee, dep. geol. sci., studies in geology, new orleans, 51–89. berggren, w.a. & pearson, p.n. (2005): a revised tropical to subtropical paleogene planktonic foraminifera zonation.– journal of foraminiferal research, 35/4, 279–298. berggren, w.a., kent, d.v., swisher c.c. & aubry, m. (1995): a revised cenozoic geochronology and chronostratigraphy.– in: berggren, w.a., kent, d.v., aubry, m. & hardenbol, j. (eds.): geochronology, time scales and global stratigraphic correlation.– special publication of society for sedimentary geology, 129–212. doi: 10.2110/pec.95.04.0129 birch, h.s., coxall, h.k. & pearson, p.n. (2012): evolutionary ecology of early paleocene planktonic foraminifera: size, depth habitat and symbionts.– paleobiology, 38/3, 374‒390. doi: 10.1666/11027.1 boersma, a. (1988): foraminifera.– in: haq, b.u. & boersma, a. (eds.): introduction to marine micropaleontology.– elsevier science, singapore, 19–78. doi: 10.1016/b978-044482672-5/50002-7 boersma, a. & premoli silva, i. (1991): distribution of paleogene planktonic foraminifera – analogies with the recent?– palaeogeography, palaeoclimatology, palaeoecology, 83, 29–48. doi: 10.1016/0031-0182(91)90074-2 bolli, h.m., beckmann, j.p. & saunders, j.b. (1994): benthic foraminifera biostratigraphy of the south caribbean region.– cambridge university press, 408 p. brew, g.e. (2001): tectonic evolution of syria interpreted from integrated geophysical and geological analysis.– phd thesis, cornell university, ithaca, new york, 323 p. brew, g., barazangi, m., al-maleh, a.k. & sawaf, t. (2001): tectonic and geologic evolution of syria.– geoarabia, 6/4, 573–616. caron, m. (1985): cretaceous planktonic foraminifera.– in: bolli, h.m., saunders, j.b. & perch nielsen, k. (eds.), planktonic stratigraphy.– cambridge university press, cambridge, 17–86. cavelier, c., chateauneuf, j., pomerol, c., rabussier, d., renard, m. & vergnaud-grazzini, c. (1981): the geological events at the eocene/oligocene boundary.– palaeogeography, palaeoclimatology, palaeoecology, 36, 223–248. doi: 10.1016/0031-0182(81)90108-5 chaimov, t a., barazangi, m., al-saad, d., sawaf, t. & gebran, a. (1992): mesozoic and cenozoic deformation inferred from seismic stratigraphy in the southwestern intracontinental palmyride fold-thrust belt, syria.– geol. soc. am. bull., 104, 704‒715. doi: 10.1130/0016-7606(192)104 cohen, k.m., finney, s.c., gibbard, p.l. & fan, j.-x. (2013; updated): the ics international chronostratigraphic chart. episodes, 36, 199‒204. url: http://www.stratigraphy.org/icschart/chronostratchart2020-01.pdf dacer, g., stanković, d., mesić, i.a. & ivaniček, z. (2007): upper campanian to maastrichtian foraminiferal assemblages of the palmyra region, syria.– geophysical research abstracts, cd, european geosciences union, vienna, 9. d’hondt, s., zachos, j.c. & schultz, g. (1994): stable isotops signals and photosymbiosis in late paleocene planktic foraminifera.– paleobiology, 20/3, 391–406. edgar, k.m., wilson. p.a., sexton, p.f., gibbs, s.j., roberts, a.p. & norris, r.d. (2010): new biostratigraphic, magnetostratigraphic and isotopic insights into the middle eocene climatic optimum in low latitudes.– palaeogeography, palaeoclimatology, palaeoecology, 297, 670–682. doi: 10.1016/j.palaeo.2010.09.016 flügel, e. (2010): microfacies of carbonate rocks.– springer, 984 p. doi: 10.1007/9783-642-03796-2 gasiński, m.a. & uchman, a. (2009): latest maastrichtian foraminiferal assemblages from the husów region (skole nappe, outer carpathians, poland).– geologia charpatica, 60/4, 283–294. doi: 10.2478/v10096-009-0020-5 gawor-biedowa, e. (1984): foraminiferal zonation of the upper cretaceous deposites in poland (except for the carpathians and sudeten). second international symposium of benthic foraminifera, pau, benthos′83.– revue de paléobiologie, 1, 213–233. gräfe, k.u. (2005): late creatceous benthic foraminifers from the basque-cantabrian basin, northern spain.– journal of iberian geology, 31/2, 277–298. guasti, e. & speijer, r.p. (2007): the paleocene‒eocene thermal maximun of the planktic foraminiferal record.– gsa special papers, 424, 53‒67. hallock, p. (1987): fluctuations in the trophic resource continuum: a factor in global diversity cycles.– paleoceanography, 215, 457–471. doi: 10.1029/pa002i005p00457 hallock, p., premoli silva, i. & boersma, a. (1991): similarities between planktonic and larger foraminiferal evolutionary trends through paleogene paleoceanographic changes.– palaeogeography, palaeoclimatology, palaeoecology, 83, 49–64. doi: 10.1016/0031-0182(91)90075-3 haq, b.u. (1981): paleogene paleoceanography: early cenozoic oceans revisited.– oceanographica acta, suppl. to vol. 4, proc. 26th int. geol. congress, 71−82. haq, b.u., hardenbol, j. & vail, p.r. (1987): chronology of fluctuating sea levels since the triassic.– science, 235, 1156‒1167. doi: 10.1126/science.235.4793.1156 hardenbol, j., thierry, j., farley, m.b., jacquin, t., de graciansky, p.c. & vail, p.r. (1998): mesozoic and cenozoic sequence chronostratigraphic framework of european basins.– sepm special publication 60, 3–13. doi: 10.2110/ pec.98.02.0003 hemleben, c., spindler, m. & anderson, o.r. (1989): modern planktonic foraminifera.– springer-verlag, new york, 363 p. doi: 10.1007/978-1-4612-3544-6 hemleben, c., muhlen, d., olsson, r.k. & berggren, w. (1991): surface texture and the first occurrence of spines in planktonic foraminifera from the early tertiary.– geologische jahrbuch, 128, 117‒146. hernitz kučenjak, m., premec fućek, v. & slavković, r. (2005): planktonic foraminifera turnover at the eocene/oligocene boundary (palmyra region, syria).– in: velić, i., vlahović, i. & biondić, r. (eds.): proceedings, third croatian geological congress, opatija, 55–56. hernitz kučenjak, m., premec fućek, v., slavković, r. & mesić, i.a. (2006): planktonic foraminiferal biostratigraphy of the late eocene and oligocene in the palmyride area, syria.– geologia croatica, 59/1, 19–39. hernitz kučenjak, m. (2008): oligocene planktonic foraminiferal associations from selected localities of neotethys.– master thesis, university of zagreb, faculty of science, zagreb, 101 p. hernitz kučenjak, m., premec fućek, v., huber, b.t. & wade, b.s. (2014): the test size and abundance variations in planktonic foraminifera chi­ loguembelina cubensis and c. ototara as response to climatic events in the oligocene. cbep 2014, ferrara, italy, july 1‒6.– in: dickens, g. & luciani, v. g eologia c roatica premec fućek et al.: planktonic foraminiferal biostratigraphy and lithology of the upper cretaceous (upper campanian-maastrichtian) ... 31 (eds.): rendiconti online della società geologica italiana, roma, 31, 103‒104. doi: 10.3301/rol.2014.68 huber, b., hodell, d.a. & hamilton, c.r. (1995): middle–late cretaceous of the southern high latitudes: stable isotopic evidence for minimal equator-to-poole thermal gradients.– gsa bulettin, 1164–1191. doi: 10.1130/00167606(1995)107 <1164:mlccot>2.3.co;2 iaccarino, s.m., premoli silva, i., biolzi, m., foresi, m., lirer, f. & petrizzo, m.r. (2005): practical manual of oligocene to middle miocene planktonic foraminifera.– international school on planktonic foraminifera, universita degli studi di perugia, università degli studi di parma, universita degli studi di milano, 124 p. ismail, a.a. (1992): maastrichtian-early eocene benthonic foraminiferal biostratigraphy and palaeoecology of west central sinai, egypt.– m.e.r.c. ain shams university, earth science series, 6, 139–150. ismail, a.a., hussein-kamel, y., boukhary, m. & ghandour, a.a.a. (2007): campanian-early eocene stratigraphy of the southern galala plateau, eastern desert, egypt.– geologia croatica, 60/2, 115–137. kaiho, k. (1998): phylogeny of deep-sea calcareous trochospiral benthic foraminifera: evolution and diversification.– micropaleontology, 44/3, 291–311. doi: 10.2307/1486051 katz, m., miller, k.g., wright, j.d., wade, b.s., browning. j.v., cramer, b.s. & rosenthal, y. (2008): stepwise transition from the eocene greenhouse to the oligocene icehouse.– nature geoscience, 1, 44/3, 229–334. doi: 10.1038/ ngeo179 keller, g. (1983): biochronology and paleoclimatic implications of middle eocene to oligocene planktonic foraminiferal faunas.– marine micropaleontology, 7, 463–486. koutsoukos, e.a.m. (2014): phenotypic plasticity, speciation, and phylogeny in early danian planktic foraminifera.– journal of foraminiferal research, 44/2, 109–142. doi: 10.2113/gsjfr.44.2.109 krasheninnikov, v.a., golovin, d.i. & mouravyov, v.i. (1996): the paleogene of syria – stratigraphy, lithology, geochronology.– geologisches jahrbuch reiche b, b 86, 136. križ, j., foršek, g., ivković, ž. & lučić, d. (2005): hydrocarbon discoveries in syria-carboniferous, permian and triassic petroleum systems.– in: velić, i., vlahović, i. & biondić, r. (eds.): proceedings, third croatian geological congress, opatija, croatia, 79–80. litak, r.k., barazangi, m., brew, g., sawaf, t. & al-youssef, w. (1998): structure and evolution of the petroliferous euphrates graben system, southeast syria.– aapg bulletin, 82/6, 1173–1190. loeblich, a.r. & tappan, h. (1988): foraminiferal genera and their classification. treatise on invertebrate paleontology.– van nostrand reinhold company, 970 p. luciani, v., d’onofrio, r., dickens, g.r., & wade, b.s. (2017a): did photosymbiont bleaching lead to the demise of planktic foraminifer morozovella at the early eocene climatic optimum?– paleoceanography, 32, 1115–1136. luciani, v., d’onofrio, r., dickens, g.r. & wade, b.s. (2017b): planktic foraminiferal response to early eocene carbon cycle perturbations in the southeast atlantic ocean (odp site 1263).– global and planetary change, 158, 119‒133. doi: 10.1016/j.gloplacha.2017.09.007 lučić, d. & foršek, g. (2000): palmyride evolution: geologic, stratigraphic and structural overview (central syria).– in: vlahović, i. & biondić, r. (eds.): proceedings, second croatian geological congress, cavtat, croatia, 311–316. lučić, d. (2001): litostratigraphical and petrographical guidebook of the typical facies in the wider area of hayan block (palmyrides, syria).– ina report, damascus, 47 p. lučić, d., maretić, s., foršek, g., takač, d. & mesić, i. (2002): mesozoic carbonate facies and reservoirs in central palmyrides, syria.– abstract, cd, ameri can association of petroleum geologists conference, cairo. ly, a. & kuhnt, w. (1994): late cretaceous benthic foraminiferal assemblages of the casamance shelf (senegal, nw africa). indication of a late cretaceous oxygen minimum zone.– revue de micropaléontologie, 37/1, 49–74. mackensen, a. (2004): changing southern ocean palaeocirculation and effects on global climate.– antarctic science, 16/4, 369–386. doi: 10.1017/ s0954102004002202 macleod, k.g., whitney, d.l., huber, b.t. & koeberl, c. (2007): impact and extinction in remarkably complete cretaceous-tertiary boundary sections from demerara rise, tropical western north atlantic.– gsa bulletin, 119, 1/2, 101‒115. doi: 10.1130/b25955.1 miller, k.m., browning, j.v., aubry,m.-p., wade, b.s., katz, m.e., kulpecz, a.a. & wright, j.d. (2008): eocene–oligocene global climate and sea-level changes: st. stephens quarry, alabama.– gsa bulletin, 120,1/2, 34‒53. doi: 10.1130/b26105.1 miller, k.g., janecek, t.r., katz, m. & keil, d.j. (1987): abyssal circulation and benthic foraminiferal changes near the paleocene/eocene boundary.– paleoceanography, 2/6, 741‒761. doi: 10.1029/pa002i006p00741 mouty, m. & al-maleh, k. (1983): the geological study of the palmyridian chain using ideal geological sections for exploration purposes and geological survey.– general establishment of geology and mineral resources, ministry of petroleum and mineral resources, damascus, syria, 4, 950 p. murray, j.w. (1991): ecology and paleoecology of benthic foraminifera.– longman scientific & technical, essex, 397 p. norris, r.d. (1996): symbiosis as an evolutionary innovation in the radiation of paleocene planktonic foraminifera.– paleobiology, 22, 461‒480. olsson, r.k., hemleben, c., berggren, w.a. & huber, b.t. (1999): atlas of paleocene planktonic foraminifera.– smithsonian contributions to paleobiology, no. 85, smithsonian institution press, washington d.c., 252 p. doi: 10.5479/ si.00810266.85.1 pearson, p.n., shackleton, n.j. & hall, m.a. (1993): stable isotope paleoecology of middle eocene planktonic foraminifera and multi-species isotope stratigraphy, dsdp site 523, south atlantic.– journal of foraminiferal research, 23/2, 123–140. doi: 10.2113/gsjfr.23.2.123 pearson, p.n. (1998): stable isotopes and the study of evolution in planktonic foraminifera.– in: norris, r.d. & corfield, r.m. (eds.): isotope paleobiology and paleoecology.– paleontol. soc. papers, 4, 138–178. doi: 10.1017/ s1089332600000425 pearson, p.n., ditchfield, p.w., signano, j., harcourt-brown, k.g., nicholas, c.j., olsson, r.k., shackleton, n.j. & hall, m.a. (2001): warm tropical sea surface temperatures in the late cretaceous and eocene epochs.– nature, 413, 481–487. doi: 10.1038/35097000 pearson, p.n., olsson, r.k., huber, b.t., hemleben, c. & berggren, w.a. (2006): atlas of eocene planktonic foraminifera.– the cushman foundation for foraminiferal research, special paper, 41, 513 p. pecimotika, g., cvetko tešović, b. & premec fućek, v. (2014): planktonic foraminiferal biostratigraphy and paleoecology of upper cretaceous deposits from the palmyride region, syria.– geologia croatica, 67/2, 87‒110. doi: 10.4154/ gc.2014.07 pérez rodrígez, i., lees, j.a., larrasoana, j.c., arz, j.a. & arenillas, i. (2012): planktonic foraminiferal and calcareous nannofossil biostratigraphy and magnetostratigraphy of the uppermost campanian and maastrichtian at zumaia, northern spain.– cretaceous research, 37, 100–126. doi: 10.1016/j.cretres.2012.03.011 petrizzo, m.r. (2002): palaeocenographic and palaeoclimatic inferences from late cretaceous planktonic foraminiferal assemblages from the exmouth plateau (odp sites 762 and 763, eastern indian ocean).– marine micropaleontology, 45, 117‒150. petrizzo, m.r., falzoni, f. & premoli silva, i. (2011): identification of the base of the lower to middle campanian globotruncana ventricosa zone: comments on reliability and global correlations.– cretaceous research, 32, 387–405. pettijohn, f.j. (1975): sedimentary rocks.– 3rd ed., harper and row, new york, ny. premec-fućek, v., pearson, p.n. & hernitz kučenjak, m. (2010): the biostratigraphy and stable isotope paleoecology of the late middle eocene planktonic foraminifera (north adriatic sea, croatia).– forams 2010, september 5–10, abstract book, 165‒166. premec-fućek, v., hernitz kučenjak, m. & huber, b. (2018): taxonomy, biostratigraphy, and phylogeny of oligocene chiloguembelina and jenkinsina.– in wade et al. (eds.): atlas of oligocene planktonic foraminifera. cush. found. spec publ., 46, 528 p. premoli silva, i. & boersma, a. (1988): atlantic eocene planktonic foraminiferal historical biogeography and paleohydrogeographic indices.– paleogeography, paleoclimatology, paleoecology, 67, 315–356. premoli silva, i. & sliter, w., v. (1995): cretaceous planktonic foraminiferal biostratigraphy and evolutionary trends from the bottacioni section, gubbio, italy.– paleontographica italica 82, 1–89. premoli silva, i. & sliter, w.v. (1999): cretaceous paleoceanography: evidence from planktonic foraminiferal evolution.– in: barrera, e. & johnson, c.c. (eds.): the evolution of cretaceous ocean–climatic system.– gsa, special paper, 332, 301–328. doi: 10.1130/0-8137-2332-9.301 premoli silva, i. & verga, d. (2004): practical manual of cretaceous planktonic foraminifera. international school on planktonic foraminifera.– in: verga, d. & rettori, r. (eds.): international school on planktonic foraminifera, 3rd course: cretaceous. university of perugia and milano, tipografia pontfelecino, perugia (italy), p. 283. premoli silva, i. & petrizzo, m.r. (2006): practical manual of eocene planktonic foraminifera.– international school on planktonic foraminifera, universita degli studi di perugia, universita degli studi di milano. perugia, 248 p. quillévéré, f., norris, r., moussa, i. & berggren, w. (2001). role of photosymbiosis and biogeography in the diversification of early paleogene acarininids (planktonic foraminifera).– paleobiology, 27/2, 311–326. robaszynski, f., caron, m., gonzales, j.m. & wonders, a.h. (eds.) (1984): atlas of late cretaceous globotruncanids.– revue de micropaleontologie, 26, 145–305. https://doi.org/10.1130/0016-7606(1995)107%3c1164:mlccot%3e2.3.co;2 https://doi.org/10.1130/0016-7606(1995)107%3c1164:mlccot%3e2.3.co;2 g eo lo gi a c ro at ic a geologia croatica 74/132 robaszynski, f. & caron, m. (1995): foraminifers planctoniques du crétacé: commentaire de la zonation europe-méditerrané.– bulletin de la société géologique de france, 6, 681–692. sari, b. (2006): upper cretaceous planktonic foraminiferal biostratigraphy of the bey dağlari autochthon in the korkuteli area, western taurides, turkey.– journal of foraminiferal research, 36, 241–261. doi: 10.2113/gsjfr.36.3.241 sari, b. (2009): planktonic foraminiferal biostratigraphy of the coniacian-maastrichtian sequences of the bey dağlari autochton, western taurides, turkey: thin-section zonation.– cretaceous research, 30, 1103–1132. sexton, p.f., wilson, p.a. & pearson, p.n. (2006): palaeoecology of late middle eocene planktic foraminifera and evolutionary implications.– marine micropaleontology, 60/1–6, 1–15. doi: 10.1016/j.marmicro.2006.02.006 shackleton, n.j., corfield, r.m. & hall, m.a. (1985): stable isotope data and the ontogeny of paleocene planktonic foraminifera.– journal of foraminiferal research, 15/4, 321–336. doi: 10.2113/gsjfr.15.4.321 spezzaferri, s. & premoli silva, i. (1991): oligocene planktonic foraminiferal biostratigraphy and paleoclimatic interpretation from hole 538a, dsdp leg 77, gulf of mexico.– paleogeography, paleoclimatology, palaeoecology, 83, 217–236. doi: 10.1016/0031-0182(91)90080-b spezzaferri, s. (1994): planktonic foraminiferal biostratigraphy and taxonomy of the oligocene and lower miocene in the oceanic record. an overview.– paleontographica italica, 81, 1–187. spezzaferri, s., basso, d. & coccioni, r. (2002): late eocene planktonic foraminiferal response to an extraterrestrial impact at massignano gssp (northeastern appennines, italy).– journal of foraminiferal research, 32/2, 188–199. doi: 10.2113/0320188 stanković, d., premec fućek, v., hernitz kučenjak, m., marić đureković, ž., ivak, p., slavković, r. & barbić, z. (2003): biostratigraphy and sedimentology of the campanian and maastrichtian sediments in the palmyra-1 well, palmyrides, syria.– in: vlahović, i. (ed.): abstracts book, 22nd ias meeting of sedimentology, opatija, croatia, p. 201. stanković, d., mesić, i.a., ivaniček, z., hernitz kučenjak, m. & premec fućek, v. (2005): upper campanian to maastrichtian foraminiferal assemblages of the palmyra region, syria.– in: velić, i., vlahović, i. & biondić, r. (eds.): proceedings, third croatian geological congress, opatija, croatia, p. 127. tomljenović, b., veseli, v. & takač, d. (2008): surface and subsurface structural styles in central syria.– faculty of mining, geology and petroleum engineering, university of zagreb, croatia, 81 p. van der zwaan, g.j., jorissen, f.j. & de stigter, h.c. (1990): the depth dependency of planktonic/benthic foraminiferal ratios: constraints and applications.– marine geology, 95, 1–16. doi: 10.1016/0025-3227(90)90016-d wade, b.s. (2004): planktonic foraminiferal biostratigraphy and mechanisms in the extinction of morozovella in the late middle eocene.– marine micropaleontology, 51, 23–38. doi: 10.1016/j.marmicro.2003.09.001 wade, b.s., pearson, p.n., berggren, w.a. & pälike, h. (2011): review and revision of cenozoic tropical planktonic foraminiferal biostratigraphy and calibration to the geomagnetic polarity and astronomical time scale.– earth-science reviews, 104, 111‒142. doi: 10.1016/j.earscirev.2010.09.003 wade, b.s. (2012): successive extinction of muricate planktonic foraminifera (morozovelloides and acarinina) as a candidate for marking the base priabonian.– newsletters on stratigraphy, 45/3, 245‒262. doi: 10.1127/0078-0421/2012/0023 wade, b.s., olsson, r., pearson, p.n., huber, b.t. & berggren, w.a. (2018): atlas of oligocene planktonic foraminifera.– the cushman foundation for foraminiferal research, special publication, 46, 528 p. widmark, j.g.v. & speijer, r.p. (1997): benthic foraminiferal faunas and trophic regimes at the terminal cretaceous tethyan seafloor.– palaios, 12, 354–371. doi: 10.2307/3515335 zachos, j., pagani, m., sloan, l., thomas, e. & billups, k. (2001): trends, rhythms, and aberrations in global climate 65 ma to present.– science, 292, 686–693. doi: 10.1126/science.1059412 zachos, j.c., quinn, t.m. & salamy, k.a. (1996): high-resolution (104 years) deep-sea foraminiferal stable isotope records of the eocene–oligocene climate transition.– paleoceanography, 11/3, 251–266. g eologia c roatica premec fućek et al.: planktonic foraminiferal biostratigraphy and lithology of the upper cretaceous (upper campanian-maastrichtian) ... 33 appendix list of planktonic foraminifera species cited in the text and figure explanation, in alphabetic order according to genus: cretaceous archaeoglobigerina blowi pessagno, 1967 contusotruncana contusa (cushman, 1926) contusotruncana fornicata (plummer, 1931) gansserina gansseri (bolli, 1951) globotruncana aegyptiaca nakkady, 1950 globotruncana arca (cushman, 1926) globotruncana bulloides vogler, 1941 globotruncana conica (white, 1928) globotruncana insignis gandolfi, 1955 globotruncana rosetta (carsey, 1926) globotruncana ventricosa white, 1928 globotruncanella havanensis (voorwijk 1937) globotruncanella pschadae (keller, 1946) globotruncanita angulata (tilev, 1951) globotruncanita conica (white, 1928) globotruncanita stuarti (de lapparent, 1918) heterohelix globulosa (ehrenberg, 1840) heterohelix striata (ehrenberg, 1840) macroglobigerinelloides alvarezi (eternod olvera, 1959) macroglobigerinelloides bollii (pessagno, 1967) macroglobigerinelloides prairiehillensis (pessagno, 1967) muricohedbergella holmdelensis (olsson, 1964) muricohedbergella monmouthensis (olsson, 1960) plummerita hantkeninoides (bröennimann, 1952) pseudotextularia elegans (rzehak, 1891) racemiguembelina fructicosa (egger, 1902) radotruncana calcarata (cushman, 1927) radotruncana subspinosa (pessagno, 1960) rugoglobigerina macrocephala bröennimann, 1952 rugoglobigerina rugosa (plummer, 1926) palaeogene acarinina bullbrooki (bolli, 1957) acarinina coalingensis (cushman & hanna, 1927) acarinina collactea (finlay, 1939) acarinina cuneicamerata (blow, 1979) acarinina echinate (bolli, 1957) acarinina mcgowrani wade & pearson, 2006 acarinina mckannai (white, 1928) acarinina medizzai (toumarkine & bolli, 1975) acarinina pentacamerata (subbotina, 1947) acarinina praetopilensis (blow, 1979) acarinina primitive (finlay, 1947) acarinina pseudotopilensis subbotina, 1953 acarinina quetra (bolli, 1957) acarinina rohri (brönnimann & bermúdez, 1953) acarinina sibaiyaensis (el-naggar, 1966) acarinina soldadoensis (brönnimann, 1952) acarinina topilensis (cushman, 1925) cassigeriella chipolensis (cushman & ponton, 1932) catapsydrax unicavus bolli, loeblich & tappan, 1957 chiloguembelina adriatica premec fućek, hernitz kučenjak & huber, 2018 chiloguembelina andreae premec fućek, hernitz kučenjak & huber, 2018 chiloguembelina crinita (glaessner, 1937) chiliguembelina cubensis (palmer, 1934) chiloguembelina midwayensis (cushman, 1940) chiloguembelina morsei (kline, 1943) chiloguembelina ototara (finlay, 1940) chiloguembelina wilcoxensis (cushman & ponton, 1932) ciperoella anguliofficinalis (blow, 1969) ciperoella angulisuturalis (bolli, 1957) ciperoella ciperoensis (bolli, 1954) cribrohantkenina inflata (howe, 1928) dentoglobigerina galavisi (bermúdez, 1961) dentoglobigerina pseudovenezuelana (blow & banner, 1962) dentoglobigerina tapuriensis (blow & banner, 1962) dentoglobigerina tripartita (koch, 1926) eoglobigerina edita (subbotina, 1953) eoglobigerina eobulloides (morozova, 1959) globanomalina archeocompressa (blow, 1979) globanomalina australiformis (jenkins, 1966) globanomalina chapmani (parr, 1938) globanomalina compressa (plummer, 1927) globanomalina ehrenbergi (bolli, 1957) globanomalina imitata (subbotina, 1953) globanomalina planocompressa (shutskaya, 1965) globanomalina planoconica (subbotina, 1953) globanomalina pseudomenardii (bolli, 1957) globigerina officinalis subbotina, 1953 globigerinatheka barri brönnimann, 1952 globigerinatheka curryi proto decima & bolli, 1970 globigerinatheka index (finlay, 1939) globigerinatheka kugleri (bolli, loeblich & tappan, 1957) globigerinatheka luterbacheri bolli, 1972 globigerinatheka subconglobata (shutskaya, 1958) globigerinatheka tropicalis (blow & banner, 1962) globoturborotalita martini (blow & banner, 1962) globoturborotalita occlusa (blow & banner, 1962) globoturborotalita ouachitaensis (howe & wallace, 1932) guembelitrioides nuttalli (hamilton, 1953) hantkenina alabamensis cushman, 1924 hantkenina dumblei weinzierl & applin, 1929 hantkenina nanggulanensis hartono, 1969 igorina albeari (cushman & bermúdez, 1949) igorina broedermanni (cushman & bermúdez, 1949) igorina pusilla (bolli, 1957) igorina tadjikistanensis (bykova, 1953) jenkinsina columbiana (howe, 1939) morozovella acuta (toulmin, 1941) morozovella aequa (cushman & renz, 1942) morozovella angulata (white, 1928) morozovella aragonensis (nuttall, 1930) morozovella crater (hornibrook, 1958) morozovella edgari (premoli silva & bolli, 1973) morozovella formosa (bolli, 1957) g eo lo gi a c ro at ic a geologia croatica 74/134 morozovella occlusa (loeblich & tappan, 1957) morozovella pasionensis (bermudéz, 1961) morozovella praeangulata (blow, 1979) morozovella subbotinae (morozova, 1939) morozovella velascoensis (cushman, 1925) morozovelloides bandyi (fleisher, 1974) morozovelloides coronatus (blow, 1979) morozovelloides crassatus (cushman, 1925) morozovelloides lehneri (cushman & jarvis, 1929) paragloborotalia griffinoides olsson & pearson, 2006 parasubbotina pseudobulloides (plummer, 1927) planorotalites pseudoscitula (glaessner, 1937) praemurica inconstans (subbotina, 1953) praemurica? lozanoi (colom, 1954) praemurica pseudoinconstans (blow, 1979) pseudohastigerina micra (cole, 1927) pseudohastigerina naguewichiensis (myatliuk, 1950) pseudohastigerina wilcoxensis (cushman & ponton, 1932) streptochilus martini (pijpers, 1933) streptochilus pristinum brönnimann & resig, 1971 subbotina cancellata blow, 1979 subbotina corpulenta (subbotina, 1953) subbotina crociapertura blow, 1979 subbotina eocaena (guembel, 1968) subbotina linaperta (finlay, 1939) subbotina senni (beckmann, 1953) subbotina triangularis (white, 1928) subbotina triloculinoides (plummer, 1927) subbotina trivialis (subbotina, 1953) subbotina utilisindex (jenkins & orr, 1973) subbotina velascoensis (cushman, 1925) subbotina yeguaensis (weinzierl & applin, 1929) tenuitella gemma (jenkins, 1966) trilobatus primordius (blow & banner, 1962) turborotalia ampliapertura (bolli, 1957) turborotalia cerroazulensis (cole, 1928) turborotalia cocoaensis (cushman, 1928) turborotalia cunialensis (toumarkine & bolli, 1970) turborotalia frontosa (subbotina, 1953) turborotalia increbescens (bandy, 1949) turbototalia pomeroli (toumarkine & bolli, 1970) turbototalia possagnoensis (toumarkine & bolli, 1970) woodringina claytonensis loeblich & tappan, 1957 zeauvigerina waiparaensis (jenkins, 1966) g eologia c roatica premec fućek et al.: planktonic foraminiferal biostratigraphy and lithology of the upper cretaceous (upper campanian-maastrichtian) ... 35 plate 1 figs. 1–15, upper campanian–maastrichtian; scale bar 100 μm. 1. gansserina gansseri, j-5, 1360–1370 m; 2. globotruncanita conica, j-5, 1370–1380 m; 3. globotruncana aegyptiaca, j-3, 1540–1545 m; 4. globotruncana arca, j-3, 1540–1545 m; 5. globotruncana ventricosa, j-4, 1735–1755 m; 6. globotruncanella havanensis, j-5, 1360–1370 m; 7. rugoglobigerina rugosa, j-5, 1340–1350 m; 8. globotruncana bulloides, j-5, 1370–1380 m; 9. macroglobigerinelloides prairiehillensis, j-4, 1735–1755 m; 10. macroglobigerinelloides bolli, j-4, 1735–1755 m; 11.  muricohedbergella holmdelensis, j-4, 1735–1755 m; 12. muricohedbergella monmouthensis, j-4, 1735–1755 m; 13. heterohelix globulosa, j-5, 1340–1350 m; 14.  archaeoglobigerina blowi, j-4, 1735–1755 m; 15. pseudotextularia elegans, j-5, 1340–1350 m. g eo lo gi a c ro at ic a geologia croatica 74/136 plate 2 figs. 1–7, lower palaeocene; figs. 8–15; upper palaeocene; scale bar 100 μm 1. eoglobigerina eobulloides, 1700–1710 m; 2. parasubbotina pseudobulloides, j-3, core-2, 1604–1613 m, i m, 20 cm; 3. woodringina claytonensis, j-2, 1700–1710 m; 4. and 5. subbotina triloculinoides, j-3, 1540–1545 m; 6. chiloguembelina morsei, j-3, 1540–1545 m; 7. morozovella praeangulata, j-2, 1550–1560 m; 8. morozovella an­ gulata, j-3, 1285–1290 m; 9. morozovella angulata j-2, 1540–1550 m; 10. igorina pussila, j-2, 1510–1520 m; 11. subbotina cancellata, j-2, 1450–1460 m; 12. subbotina cf. triangularis, j-2, 1270–1280 m; 13. acarinina coalingensis, j-2, 1370–1380 m; 14. acarinina cf. soldadoensis, j-2, 1285–1290 m; 15. acarinina sp., j-2, 1300-1310 m. g eologia c roatica premec fućek et al.: planktonic foraminiferal biostratigraphy and lithology of the upper cretaceous (upper campanian-maastrichtian) ... 37 plate 3 figs. 1–12, lower eocene, scale bar 100 μm 1. morozovella subbotinae, j-2, 1160–1180 m; 2. morozovella aequa, j-2, 1160–1180 m; 3. acarinina pentacamerata, j-3, core-1 (842-852 m), vii m, 70 cm; 4. globano­ malina planoconica., j-2, 1070–1080 m; 5. igorina cf. broedermanni, j-2, 1200–1220 m; 6. acarinina cuneicamerata, j-3, core-1 (842–852 m), vii m, 70 cm; 7. acarinina bullbrooki, j-2, 1160–1170 m; 8. turborotalia frontosa, j-1, 885-890 m; 9. subbotina eocaena, j-2, 1160–1180 m; 10. subbotina eocaena j 2, 1190–1200 m; 11. subbotina linaperta, j-2, 1100-1110 m; 12. subbotina sp., j-2, 1160-1170 m. g eo lo gi a c ro at ic a geologia croatica 74/138 plate 4 figs. 1–12, middle eocene, scale bar 100 μm 1. hantkenina cf. dumblei, j-3, 520–530 m; 2. globigerinatheka curryi, j-3, 520–530 m; 3. globigerinatheka subconglobata, j-3, 520–530 m; 4. morozovelloides cf. ban­ dyi, j-2, 720–740 m; 5. acarinina mcgowrani, j-2, 680–700 m; 6. acarinina topilensis, j-1, 540–550 m; 7. morozovelloides crassatus, j-3, 520-530 m; 8. morozovelloides lehneri, j-2, 720–740 m; 9. subbotina eocaena, j-3, 520–530 m; 10. subbotina linaperta, j-1, 540–560 m; 11. turbototalia pomeroli, j-1, 700–720 m; 12. turborotalia cerroazulensis, j-1, 600–610 m. g eologia c roatica premec fućek et al.: planktonic foraminiferal biostratigraphy and lithology of the upper cretaceous (upper campanian-maastrichtian) ... 39 plate 5 figs. 1–12, upper eocene, scale bar 100 μm 1. turborotalia cerroazulensis, j-3, 370–380 m; 2. and 3. turborotalia cocoaensis, j-6, 440–460 m; 4. turborotalia ampliapetura, j-2, 560–580 m; 5. turborotalia cuni­ alensis, j-6, 440–460 m; 6. globigerinatheka barri, j-2, 600–620 m; 7. hantkenina alabamensis, j-5, 280–290 m; 8. subbotina linaperta, j-3, 370–380 m; 9. subbotina yeguaensis, j-6, 440–460 m; 10. dentoglobigerina galavisi, j-6, 440–460 m; 11. globoturborotalita ouachitaensis, j-6, 440–460 m; 12. pseudohastigerina micra, j-2, 600–620 m. g eo lo gi a c ro at ic a geologia croatica 74/140 plate 6 figs. 1–12, oligocene; scale bar 100 μm, except figs. 1, 5, 10–50 μm. 1. cassigeriella chipolensis, j-5, 190–200 m; 2. dentoglobigerina tripartita, j-6, 400–420 m; 3. dentoglobigerina tapuriensis, j-6, 400–420; 4. turborotalia ampliapertura, j-6, 360–380 m; 5. pseudohastigerina naguewichiensis, j-5, 220–230 m; 6. globigerina officinalis; j-1, 240–250 m; 7. chiloguembelina ototara, j-6, 400–420 m; 8. chiloguembelina cubensis, j-6, 360–380 m; 9. chiloguembelina adriatica, j-6, 360–380 m; 10. ciperoella anguliofficinalis, j-5, 160–170 m; 11. ciperoella angulisu­ turalis, j-4, 455–475 m; 12. ciperoella ciperoensis, j-4, 455–475 m. www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2024 | 77/2 | 69–83 | 12 figs. | 4 supplements | 1. introduction the upper miocene sandstones of the north croatian basin are major hydrocarbon reservoirs not only in croatia but also in large parts of the pannonian basin. these rocks play a vital role in the energy sector (dolton, 2006). despite decades of exploration, a comprehensive understanding of the sandstones source rocks remains unsatisfactory (e.g., šćavničar, 1979; matošević et al., 2023). this knowledge is crucial for evaluating their potential as reservoir rocks, not only for traditional oil and gas exploration but also for emerging technologies such as carbon capture, utilization, storage, and geothermal energy initiatives (e.g., sneider, 1990; horváth et al., 2015; macenić et al., 2020; alcalde et al., 2019; tuschl et al., 2022). the composition of the hinterland source rocks influences sedimentary deposits in a basin (bhatia, 1983; pettijohn et al., 1987; garzanti, 2016, 2019), shaping sediment behaviour during burial diagenesis and impacting petrophysical parameters including porosity and permeability. provenance analysis is integral to assessing reservoir development and quality (worden et al., 1997, 2018; worden & burley, the alps as the main source of sand for the late miocene lake pannon (pannonian basin, croatia) mario matošević1,*, eduardo garzanti2, sanja šuica1, danilo bersani3, frane marković4, ivan razum5, anita grizelj6, krešimir petrinjak6, marijan kovačić4 and davor pavelić7 1 ina – oil company, plc., exploration & production, field development, exploration & production laboratory, lovinčićeva 4, 10000 zagreb, croatia; (*corresponding author: mario.matosevic@ina.hr) 2 university of milano-bicocca, department of earth and environmental sciences, laboratory for provenance studies, 20126 milano, italy 3 university of parma, department of mathematical, physical and computer science, 43124 parma, italy 4 university of zagreb, faculty of science, department of geology, division of mineralogy & petrology, horvatovac 95, 10000 zagreb, croatia 5 croatian natural history museum, demetrova 1, 10000 zagreb, croatia 6 croatian geological survey, department of geology, sachsova 2, 10000 zagreb, croatia 7 university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, 10000 zagreb, croatia doi: 10.4154/gc.2024.05 abstract the provenance of the upper miocene sandstones from the sava and drava depressions of the north croatian basin was investigated using petrographic, geochemical, and heavy mineral analyses, including raman spectroscopy. the study of these sandstones, which represent important oil and gas reservoirs in croatia, allowed reconstruction of the late miocene source-to-sink model of the lake pannon drainage system and the evolution of the southwestern pannonian basin. the studied feldspatho-litho-quartzose sandstones consist of a mixture of sedimentary, metamorphic, and igneous detritus. heavy-mineral assemblages are dominated by almandine-rich garnet with apatite, epidote, tourmaline, rutile, zircon, staurolite, and zoisite, indicative of low to medium-grade metamorphic source rocks. higher concentrations of ca and mg than in the upper continental crust standard (ucc) additionally reflect the abundance of limestone and dolostone rock fragments as well as carbonate cement. geochemical compositional variations between sandstone samples from the sava and drava depressions primarily stem from diagenetic processes. cix and alpha values indicate only minor weathering. compositional features indicate an orogenic source located in the eastern alps and primarily represented by austroalpine and penninic nappes. this research offers a novel perspective to distinguish the upper miocene reservoirs from other sedimentary units within the basin, contributing to a more comprehensive understanding of the regional geological dynamics and supporting future exploration projects also related to energy transition. 2003; lawan et al., 2021). notably, the upper miocene sandstones in the north croatian basin exhibit porosity values from 10% to over 30% and permeability values from 0.01 to 1000 md (vrbanac et al., 2010; novak zelenika et al., 2010; malvić & velić, 2011; velić et al., 2012; kolenković močilac et al., 2022). this study focuses on the upper miocene sandstones derived from the two largest depressions within the north croatian basin – the sava and drava depressions (pavelić & kovačić, 2018). the research delves into the geological history of the vast expanse of lake pannon, formed by the isolation of the central paratethys from the late miocene to the early pliocene (steininger & rögl, 1979; báldi, 1980; rögl & steininger, 1983; rögl, 1998; magyar et al., 1999; harzhauser et al., 2007; piller et al., 2007; harzhauser & mandic, 2008; kováč et al., 2017, 2018; magyar, 2021). the miocene epoch in the investigated region, linked with the dynamic history of the central paratethys, witnessed the formation of the pannonian basin in the early miocene due to the subduction of the eurasian plate beneath the african plate, article history: manuscript recieved: december 29, 2023 revised manuscript accepted: february 2, 2024 available online: may 14, 2024 keywords: sandstone reservoirs, sedimentary provenance, heavy minerals, geochemical composition, north croatian basin, late miocene, eastern alps mailto:mario.matosevic@ina.hr g eo lo gi a c ro at ic a 70 geologia croatica 77/2 leading to thermal perturbations, crustal weakening, and the basin’s formation as a back-arc sedimentary basin (royden, 1988; kováč et al., 1998; pavelić, 2001; matenco & radivojević, 2012; horváth et al., 2015; pavelić & kovačić, 2018). the subsequent evolution witnessed climate shifts, tectonic activity, and the formation of lake pannon, where the upper miocene sandstones were deposited by cyclic turbiditic currents fed by the progradation of delta systems (basch et al., 1995; magyar et al., 1999, 2013; ivković et al., 2000; saftić et al., 2003; kovačić et al., 2004; kovačić & grizelj, 2006; vrbanac et al., 2010; malvić & velić, 2011; sztanó et al., 2013, 2015; balázs, 2017; balázs et al., 2018; sebe et al., 2020; anđelković & radivojević, 2021; špelić et al., 2023). the primary contributor of detrital material to the pannonian basin can be traced back to the alpine-carpathian source region (e.g., kuhlemann et al., 2002). this is particularly evident in the alcapa tectonic mega-unit within the eastern alps and western carpathians – the region mostly comprising mesozoic carbonates, proterozoic to palaeozoic low to medium-grade metamorphic rocks, and palaeozoic granitoids (e.g., asch, 2003; schmid et al., 2008, 2020; matošević et al., 2023). predominant transport trajectories align with w/nw to e/se patterns in the croatian and hungarian sectors of the basin (ivković et al., 2000; saftić et al., 2003; kovačić et al., 2004; kovačić & grizelj, 2006; magyar et al., 2013; sebe et al., 2020). however, in the serbian sector (se tip of the pannonian basin) a smaller opposite se to nw source-to-sink system from the southern carpathians was identified (radivojević et al., 2022). selected publications addressing diverse sediments in the pannonian basin and adjacent basins include kovačić (2004), grizelj et al. (2011, 2017), as well as more recent studies by arató et al. (2021), amorosi et al. (2022), and matošević et al. (2023), offer valuable insight for comparative analysis. this facilitates assessment of the provenance of the upper miocene sandstones and aids understanding of the geological dynamics involved in the north croatian basin and its broader regional context during the late miocene. this study thoroughly examines the petrographic, heavymineral, and geochemical composition of the upper miocene sandstones to reveal the nature of their source rocks, assesses the degree of weathering, traces detrital pathways, unravels mixing processes, and aids comprehension of the final mechanisms of deposition in the basin. these results will enhance future exploration and correlation of the upper miocene sandstones in the north croatian basin and the wider area of the pannonian basin and help in modeling and calibration of compositional data, incorporating methodologies including well-log and seismic interpretation. 2. geological background the north croatian basin is an elongated extensional basin covering ~32,000 km2 in northern croatia and belonging to the pannonian basin, surrounded by the alps, carpathians, and dinaride mountains (fig. 1a). the north croatian basin is characterized by various depressions and sub-depressions, with the sava depression in the south and the drava depression in the north being the largest (pavelić & kovačić, 2018; fig. 1b). the basin is filled by lower to upper miocene age strata, deposited in a range of sedimentary environments, including marine, brackish, and freshwater (pavelić, 2001; lučić et al., 2001; saftić et al., 2003; pavelić & kovačić, 2018), resting unconformably on tectonized palaeozoic to palaeogene units (e.g., pamić, 1986, 1999; šuica et al., 2022a, b). the miocene epoch in the pannonian basin is closely associated with the dynamic history of central parathetys, which repeatedly connected and disconnected with the open ocean until it was definitively isolated at ~11.6 ma (steininger & rögl, 1979; báldi, 1980; rögl & steininger, 1983; rögl, 1998; magyar et al., 1999; harzhauser et al., 2007; piller et al., 2007; harzhauser & mandic, 2008; ter borgh et al., 2013; kováč et al., 2017, 2018; magyar, 2021). the pannonian basin formed in the early miocene in connection with the subduction of the eurasian plate beneath the african (apulian) plate, involving several continental figure 1. a – geographical overview of the pannonian basin within the alpine, carpathian, and dinaride mountain ranges in central europe. b – spatial representation of the north croatian basin, encompassing the sava and drava depressions, indicating the locations of the upper miocene reservoir sandstones extracted from exploration wells. g eologia c roatica 71matošević et al.: the alps as the main source of sand for the late miocene lake pannon (pannonian basin, croatia) fragments and leading to thermal perturbations in the upper mantle, weakening and extension of the crust, and the formation of a back-arc sedimentary basin (royden, 1988; horváth, 1993, 1995; kováč et al., 1998; pavelić, 2001; matenco & radivojević, 2012; horváth et al., 2015; balázs et al., 2016; pavelić & kovačić, 2018). in the initial “syn-rift” phase of pannonian basin development, crustal thinning and isostatic subsidence led to the transition from continental to marine environments (royden, 1988; tari et al., 1992). in the north croatian basin, normal listric faulting (pavelić, 2001) formed halfgrabens and these elongated sub-basins served as main depocentres, while the climate changed from semi-arid to humid, volcanism increased, and marine transgressions and regressions were associated with the activity of normal faults (pavelić, 2001; bigunac, 2022; pavelić & kovačić, 2018; rukavina et al., 2023). subsequently, reduced tectonic activity led to lithosphere cooling and subsidence, and the whole pannonian basin was isolated from marine influences of the central paratethys (“post-rift” phase; royden, 1988; tari et al., 1992), leading to the formation of the large and long-lived lake pannon (magyar et al., 1999; harzhauser & piller, 2007; piller et al., 2007; mandic et al., 2015). the upper miocene sandstones were deposited during this stage as prograding deltas in proximal settings and as turbidites in deeper areas of lake pannon (juhász, 1994; magyar et al., 1999; ivković et al., 2000; saftić et al., 2003; kovačić & grizelj, 2006; vrbanac et al., 2010; malvić & velić, 2011; sztanó et al., 2013, 2015; balázs et al., 2018; sebe et al., 2020; anđelković & radivojević, 2021; špelić et al., 2023). in the late miocene, the north croatian basin (as for the whole pannonian basin) experienced tectonic quiescence and thermal subsidence, while the surrounding alpine-carpathiandinaric fold belt underwent uplift and erosion. along with the prevailing humid climate (sztanó et al., 2013; balázs et al., 2018), this resulted in considerable lake depths and deposition of mainly siliciclastic post-rift sediments reaching a thicknesses of several thousand metres in the central part of the depressions (juhász, 1994; ivković et al., 2000; saftić et al., 2003; kovačić & grizelj, 2006; malvić & velić, 2011; velić et al., 2012; sebe et al., 2020; matošević et al., 2023; špelić et al., 2023). in the pliocene and quaternary, the north croatian basin underwent structural inversion, strike-slip faulting, counterclockwise rotation, and uplift of basement blocks leading to the formation of the present-day mountains (jamičić, 1995; márton et al., 1999, 2002; pavelić, 2001; tomljenović & csontos, 2001). 3. methods a total of 18 samples were carefully selected from exploration wells drilled by ina (industrija nafte d.d.). nine cored sandstone samples from six different exploration wells in the sava depression and nine cored sandstone samples from six different exploration wells in the drava depression were obtained to ensure the representativeness of the studied reservoir material (fig. 1b), consistently choosing thick beds without significant sedimentary structures and considering their stratigraphic association validated by biostratigraphic analyses previously conducted by ina. well-log correlation and seismic interpretation of key regional horizons also provided essential insight for the samples’ selection. 3.1. petrography and heavy minerals petrographic analyses of the upper miocene sandstones from the sava and drava depressions, coupled with scanning electron microscope (sem) and energy dispersive x-ray spectroscopy (eds) analyses, were conducted, and docu mented by matošević et al. (2023). full and detailed results are provided in the electronic supplements, accessible online via suppl. 1. sandstone classification is after garzanti (2016, 2019). sandstone samples were crushed into pieces > 5 mm and calcite cement was subsequently dissolved using a 5% acetic acid (ch3cooh) solution, followed by treatment with 15% h2o2 to eliminate organic matter. the processed samples were then sieved, and the more dense grains were separated from the 63-125 µm fraction using sodium polytungstate (spt; density 2.90 g/cm3), followed by centrifugation at 2500 rpm for 5 minutes. over 300 transparent heavy minerals (thm) were counted on each grain mount by the ribbon method (mange & maurer, 1992). results are provided in suppl. 2. 3.2. garnet raman spectroscopy the raman spectra of 104 garnet grains from seven sandstone samples from both the sava and drava depressions, encompassing various depth intervals within the same exploration well, were acquired using a bruker senterra ii confocal raman microscope. a 532 nm laser with 12 mw output power and a x50 ld objective were employed. spectra spanning the 50-1410 cm-1 range were recorded using a highresolution grating with 1200 lines/mm, with acquisition times between 9 and 15 s. calibration was performed automatically using surecaltm technology. peak positions were discerned via lorentzian curve fitting facilitated by opus software. the six peaks characteristic of garnets were harnessed as input data for an updated version of the matlab routine miragem (micro-raman garnets evaluation method) to estimate the relative abundance of garnet end members (bersani et al., 2009; karampelas et al., 2023). the new version of the software improves the reliability of the results working on a five end members basis (uvarovite is excluded). the complete dataset is provided in suppl. 3. 3.3. geochemistry whole rock chemical analyses on all 18 sandstone samples from the sava and drava depression were conducted at bureau veritas mineral laboratories (vancouver, canada) by lithium metaborate/tetraborate fusion and nitric acid digestion. major elements were quantified using inductively-coupled-plasma emission spectroscopy (icp-es) and trace elements by inductively-coupled-plasma mass spectrometry (icp-ms) (for detailed information on adopted analytical protocol, standards, and precisions see https://acmelab.com). handling and processing of geochemical data were carried out using gcdkit https://acmelab.com g eo lo gi a c ro at ic a 72 geologia croatica 77/2 figure 2. thin-sections of the upper miocene sandstones from the sava depression (plate a): 1 – main sandy grains and intergranular volume filled with carbonate (calcite) cement (s11, ppl), 2 – the same as 1, under xpl, 3 – intergranular volume between sandy grains filled with blue-dyed epoxy showing primary porosity of the sandstone (s41, ppl), 4 – the same as 3, under xpl; and thin-sections of the upper miocene sandstones from the drava depression (plate b): 1 – main sandy grains and primary intergranular porosity (intergranular volume filled with blue-dyed epoxy) (d2, ppl), 2 – the same as 1, under xpl, 3 – intergranular volume between sandy grains filled with carbonate (calcite) cement (d6, ppl), 4 – the same as 3, under xpl. qz – quartz, fsp – feldspar, lm – metamorphic rock fragment, lv – magmatic rock fragment, ls – sedimentary rock fragment, ms – muscovite, bt – biotite, tur – tourmaline. ppl = plane-polarized light, xpl = cross-polarized light. g eologia c roatica 73matošević et al.: the alps as the main source of sand for the late miocene lake pannon (pannonian basin, croatia) 4.1 (janoušek et al., 2006) and the r provenance package (vermeesch et al., 2016). chemical data are provided in suppl. 4. 3.4. statistical analyses petrographic, heavy-mineral, and geochemical data carry compositional information stored in ratios between components (aitchison, 1986; pawlowsky-glahn et al., 2015; vermeesch, 2018). sample space for compositional data is called simplex, defined as: s x x x x x i d x kd d ii d = = [ ] > = ={ }=∑1 2 1 1 0 1 2, ,... , , ,... ; , (1) where k is usually 100. to perform log-ratio transformations and enable data treatment in euclidian space, we eliminated zero values from the dataset by using bayesian multiplicative zero replacement (martín-fernández et al., 2015). isometric log-ratio transformation (ilr; egozcue et al., 2003) was used for both heavy-mineral and geochemical data. heavy-mineral data were transformed through a sequential binary partition (sbp; egozcue & pawlowskyglahn, 2005), by which minerals are continuously split into two groups until all groups consist of one mineral only. through this procedure, variables (called balances) are constructed as invariant (i.e., they do not change during transport or diagenesis and thus preserve the original source signal; razum et al., 2021, 2023). this was of the utmost importance since the selective dissolution of heavy minerals (hm) is expected and even documented in this particular geological setting (šćavničar, 1979; matošević et al., 2023). 4. results 4.1. petrography the studied sandstones are very fine to fine grained (ranging from 80 to 130 µm in the sava depression and from 100 to 220 µm in the drava depression), well to moderately-well sorted, and mainly show tangential grain-to-grain contacts (suppl. 1; fig. 2a & b). all samples except one are classified as feldspatho-litho-quartzose carbonaticlastic, with average composition almost identical in the sava depression (q50 f14 l36, lm26 lv10 ls64; suppl. 1; fig. 3a & b) and in the drava depression (q52 f13 l35, lm26 lv10 ls64; suppl. 1; fig. 3a & b). sedimentary grains are virtually all dolostones and limestones (mudstone to packstone or grainstone), with rare chert. metamorphic rock fragments include mica schist, quartzite, gneiss, slate, and phyllites. igneous rock fragments include granitoids and altered volcanic glass or tuff. rip-up clasts also occur. porosity is mostly primary intergranular (fig. 2). the intergranular volume may be partially or completely filled by carbonate cement (calcite and ankerite), micrite, small quartz, mica or feldspar grains, phyllosilicates (including detrital and authigenic clay minerals), or even silica cement in the form of quartz overgrowths. 4.2. heavy minerals heavy mineral concentration (hmc) ranges from 0.2% to 9.6% (average: 4.8%) in the sava depression and from 3.6% to 9.1% (average: 5.5.%) in the drava depression (stab. 2). the very poor to rich thm suites (0.1 ≤ thmc ≤ 5) are garnetdominated (28-79%, average 59% in the sava depression, 3084%, average 54% in the drava depression), with apatite (average 15% in the sava depression, 27% in the drava depression), epidote (average 10% in the sava depression but negligible in the drava depression), tourmaline (2-10% in the sava depression, 2-15% in the drava depression), rutile (1-10% in the sava depression, 3-12% in the drava depression), and zircon (2% in the sava depression, 3% in the drava depression) (suppl. 2; fig. 4). clinozoisite occurs in the sava depression (average 2%) but is negligible in the drava depression. titanite, chloritoid, staurolite, zoisite, brookite, chromite, kyanite, and anatase were also detected (suppl. 2; fig. 4). 4.3. garnet raman spectroscopy the studied garnets are mostly pyralspites (suppl. 3). almandine is the main component in the majority of the analyzed figure 3. petrographic classification of the upper miocene sandstones from the sava and drava depressions presented in the qfl diagram (a) and the lmlvls diagram (b) according to garzanti (2016, 2019). g eo lo gi a c ro at ic a 74 geologia croatica 77/2 figure 4. heavy mineral association of the upper miocene sandstones from the sava and drava depressions. a – anhedral garnet with conchoidal fractures, b-f – garnet grains showing small to large-scale etch facets due to advanced dissolution, g & h – apatite grains, i-k – tourmaline grains, l & m – rutile grains, n – zircon, o – opaque mineral grain, p – epidote, q – clinozoisite, r – zoisite, s – chlorite, t – biotite, u – titanite, v – chloritoid, w – staurolite, x – chromite, y – brookite, z – anatase, a’ – kyanite. figure 5. trace element plots of the upper miocene sandstones from the sava depression (a) and the drava depression (b), normalized to the upper continental crust (ucc, tylor & mclennan, 1985). g eologia c roatica 75matošević et al.: the alps as the main source of sand for the late miocene lake pannon (pannonian basin, croatia) garnets, ranging from ~38 to ~96%. other components include spessartine (<46%), pyrope (<26%), and grossular (<26%). spessartine garnet, with spessartine 40-62%, almandine <48%, pyrope <26%, and grossular <14%, is present in most samples although less abundant (12% in the sava depression, 4% in the drava depression). 4.4. geochemistry the studied samples contain 41-63% sio2, 5.7% to 12% al2o3 (generally lower in the drava depression), and 7.6% to 22% cao (generally higher in the drava depression) (suppl. 4). al2o3 correlates best with fe2o3 (r 0.94) and k2o (r 0.92), moderately well with na2o (r 0.64) and tio2 (r 0.62), weakly with sio2 (r 0.45), insignificantly with mgo (r 0.20), and negatively with cao (r -0.75) (stab. 4). in the drava depression samples, mgo correlates positively with fe2o3, al2o3, and tio2, but negatively with cao. mg and ca are enriched, and na, k, al, and fe depleted relative to the upper continental crust standard (ucc; taylor & mclennan, 1985). the lack of correlation between ba and k2o and very high ba content in some samples were observed (fig. 5). rare earth element (ree) patterns normalized to chondrite (boynton, 1984; fig. 6) show light ree enrichment (lacn/ybcn 8.1-9.6 for the sava depression and 7.7-8.9 for the drava depression) and a distinct negative eu anomaly (eu/eu* 0.64-0.78 for the sava depression and 0.62-0.74 for the drava depression; suppl. 4). in the case of sandstones with very high carbonate content, the cia index (nesbitt & young, 1982) widely used to assess weathering effects in sediments, requires a very large correction for calcium not hosted in silicates. we thus preferred to use the cix index, a simple modification of the cia that excludes cao in the calculation (garzanti et al., 2014). virtually identical cix values characterize both the sava and drava depression sandstones (73-77). the effect of weathering is however far better detangled from other controls if mobile elements (mg, ca, na, k, tb, sr, and ba) are considered one by one. this is done by using alpha indices (αale values) − defined as (al/e) sample / (al/e) standard (garzanti et al., 2013) −, which compare the concentration of any mobile element e with reference to non-mobile al in our samples versus an appropriately selected standard composition (e.g., ucc). aluminium, hosted in a wide range of rock-forming minerals with diverse density, shape, and size, including phyllosilicates (concentrated in mud) and feldspars (concentrated in sand), is used as a reference for all elements. alpha indices are very low for ca and mg and low for sr, whereas they range between 1 for rb and 1.5 for na. figure 6. rare earth element plots of the upper miocene sandstones from the sava (a) and the drava (b) depressions, normalized to chondrite according to boynton (1984). g eo lo gi a c ro at ic a 76 geologia croatica 77/2 the th/u ratio for both depressions ranges from 2.7 to 3.8 (mclennan et al., 1993; fig. 7a) and the zr/sc ratio from 14.9 to 24.1 (mclennan et al., 1993; fig. 7b). 5. provenance analysis the studied upper miocene sandstones from the sava depression and the drava depression are mostly feldspatholitho-quartzose carbonaticlastic indicating provenance from cover strata with contribution from metamorphic and igneous rocks (fig. 2 & fig. 3). the virtually identical composition of the sava and drava depression sandstones indicates they are part of the same sedimentary system with a common dispersal path from source to sink, typical of a recycled orogen (dickinson, 1985; fig. 8). matošević et al. (2023) envisaged a provenance from mesozoic carbonates, proterozoic to palaeocene low to medium-grade metamorphic rocks, and palaeozoic granitoids of the eastern alps and southern alps, possibly with minor additional detritus from the western carpathians, but excluding significant supply from the dacia tectonic mega-unit of the eastern and southern carpathians or from the dinarides, although the latter is geographically closer to the north croatian basin than the eastern alps. this inference is supported by dominant palaeoflow directions from w/nw, as widely indicated by measurements at the outcrops and by the interpretation of seismic profiles in both the sava depression and the drava depression (ivković et al., 2000; saftić et al., 2003; kovačić et al., 2004; kovačić & grizelj, 2006; sebe et al., 2020; špelić et al., 2023). provenance from metamorphic units of the eastern alps is supported by thm suites dominated by mostly almandinerich garnet and including chloritoid, biotite, kyanite, epidote, staurolite, and zoisite (suppl. 2; fig. 4). such an assemblage closely resembles that found in modern river sediments sourced from metamorphic rocks of the eastern alps, dominated by the alcapa (adria-derived) tectonic megaunit with the austroalpine and peninic nappes (e.g., drava and mura; schmid et al., 2008, 2020; garzanti et al., 2010; arató et al., 2021; matošević et al., 2023). the differential source influence can be attributed mostly to the upper and lower austroalpine basement, as well as the upper austroalpine cover (c.f., schuster et al., 2013; bousquet et al., 2012; mencin gale et al., 2019a, 2019b; hauke et al., 2019; janák et al., 2004). though the moderately high ztr index (15 ± 8) might indicate significant recycling from older sandstones (hubert, 1962; garzanti, 2017), in this case, it is primarily attributed to the substantial diagenetic dissolution of unstable hm in the subsurface (fig. 9). statistical discrimination of the most prevalent hm in the sandstones from both depressions indicates their shared source (fig. 9). the almost complete absence of chemically labile ferromagnesian minerals indicates that thm assemblages were significantly affected by selective intrastratal dissolution, more extensive in the drava depression, and thus do not represent the original mineral suite. for this reason, we focused on garnet, one mineral that proves to be relatively resistant during burial diagenesis (morton & hallsworth, 2007; garzanti et al., 2018). according to the classification of mange & morton (2007), garnet grains in the upper miocene sandstones are mostly of type b (typical of amphibolite-facies metasedimentary rocks and granitoids), with a minority of type c (found in high-grade metamafic rocks and quartz-biotite gneisses) and type a minerals (found in granulite-facies metasediments). this is consistent with the garnet variation diagram by aubrecht et al. (2009) figure 7. a – plot of th/u versus th indicating insignificant intensity of weathering for the upper miocene sandstones from the sava and drava depressions, with values similar to the upper crust, according to mclennan et al. (1993). b – plot of th/sc versus zr/sc indicating negligible influence from sedimentary sorting or recycling for the upper miocene sandstones from the sava and drava depressions according to mclennan et al. (1993). figure 8. tectonic setting discrimination diagram of the upper miocene sandstones from the sava and drava depressions according to dickinson (1985). g eologia c roatica 77matošević et al.: the alps as the main source of sand for the late miocene lake pannon (pannonian basin, croatia) revealing most garnets align within amphibolite-facies conditions (group 4, 5, 6, and 7; fig. 10). the geochemical composition of the studied sandstones ref lects the mineralogy of both detrital and authigenic components (e.g., enrichment in cao and mgo is an effect of the abundance of both detrital and diagenetic calcite, dolomite, and ankerite; fig. 11). because of extensive carbonate cement, ca and mg are enriched, and na, k, al, and fe depleted relative to the upper continental crust standard (ucc; taylor & mclennan, 1985). calcite cement is more common in deeper-water sediments especially in the drava depression, although fully cemented sandstones also occur in shallow-water deposits (matošević et al., 2023; fig. 2). for this reason, limited provenance information can be obtained from geochemical data. the lack of correlation between ba and k2o, coupled with a very high ba content in some samples (fig. 5), reflects the presence of barite identified by sem-eds analyses (matošević et al., 2023). a comparison of the geochemical signature of the upper miocene sandstones in the north croatian basin with sediments from neighboring basins in the po-adriatic region, particularly focused on elements figure 9. discrimination of heavy mineral assemblages in the upper miocene sandstones between the sava and drava depressions. a – balance dendrogram illustrating modeled balances (b1 = log ratio of garnet over other heavy minerals, sensitive to selective dissolution; b2 = log ratio of apatite and tourmaline over zircon and rutile, ultra-stable in burial diagenesis but sensitive to selective hydraulic sorting; b3 = log ratio of tourmaline over apatite; b4 = log ratio of rutile over zircon; both b3 and b4 include ratios of minerals with the same properties, making them transportand dissolutioninvariant and thus perfect provenance signals). b – balance b1 is decreasing with depth, indicating instability (selective dissolution) of garnet over other heavy minerals during burial diagenesis. c – scatterplot of balances b3 and b4, indicating no differences in heavy mineral composition between the sava and drava depressions, indicating the same provenance. figure 10. composition of garnets in the upper miocene sandstones from the sava and drava depressions, illustrated in the classification diagram “pyrope (py)-almandine (alm)-spessartine (sp)” according to aubrecht (2009). a – garnets from hp/uhp conditions, b – garnets from granulite and eclogite facies conditions, c1 – garnets from high amphibolite to granulite facies conditions, c2 – garnets from amphibolite facies conditions, no. 1-7: source rocks of the individual garnets (refer to the original paper for details). g eo lo gi a c ro at ic a 78 geologia croatica 77/2 figure 11. discrimination of geochemical composition in the upper miocene sandstones between the sava and drava depressions. a – compositional biplot explaining over 80% of total data variation, with 50% by the first principal component (pc1). variable loadings indicate that diagenesis is the key factor in the dataset’s variation, with cao and mgo showing negative loadings, while other major elements exhibit positive loadings on pc1. b – ratio of mobile to immobile elements (b1 = ratio of mno-cao/al2o3-tio2) indicating that the geochemical difference is a result of diagenetic processes. c – box plot of balances indicating that, when considering only immobile elements (associated with the detrital component, not the cement), there is no difference between the sava and drava depressions (b3 = tio2/al2o3). d – linear discrimination based on major oxides. e – linear discrimination based on rare earth elements. d and e clearly separate the sava and drava depressions. however, as previously concluded, this separation results from diagenesis and/or sediment dispersal (i.e., sorting), as indicated by the grain size presented in f. figure 12. simplified schematic source-to-sink model of the upper miocene sandstones from the north croatian basin. this model shows a broader view of the late miocene lake pannon region. the sediments from the sava and drava depressions exhibit virtually identical compositions, suggesting a common source in the alps during the late miocene. rapid subsidence within the pannonian basin facilitated substantial fluvial sediment transfer, potentially via the palaeo-sava and/or palaeo-drava river systems, from mountains to the lake. however, the connection with the palaeo-danube remains uncertain. the model is based on insights gleaned from previous studies (e.g., magyar et al., 2013; sztanó et al., 2013; pavelić & kovačić, 2018; sebe et al., 2020; matošević et al., 2023; špelić et al., 2023) and the findings of this research. it is important to note that the model represents a simplified overview in the late miocene, and possible islands and underwater elevations in the lake are not outlined. g eologia c roatica 79matošević et al.: the alps as the main source of sand for the late miocene lake pannon (pannonian basin, croatia) such as ni, cr, or v diagnostic of mafic-ultramafic source rocks (e.g., mclennan et al., 1993; amorosi et al., 2022), indicates a close affinity with river sediments derived from the eastern alps rather than the dinarides or the carpathians. the similar cix and alpha values suggest only minor weathering effects. very low alpha indices for ca and mg and low values for sr reflect the abundance of carbonates, whereas the range between 1 for rb and 1.5 for na indicates a very low weathering intensity. furthermore, the th/u ratio analysis also dismisses the presence of significant weathering processes (mclennan et al., 1993; fig. 7a). similarly, the zr/sc ratio indicates the inconsequential impact of sedimentary sorting or recycling (mclennan et al., 1993; fig. 7b), aligning with findings from prior research by matošević et al. (2023). during the late miocene, the eastern alps underwent significant uplift concurrent with the rapid subsidence of the pannonian basin, thus creating the conditions for massive fluvial sediment transfer from the mountains to the basin (fig. 12). previous investigations in the north croatian basin are consistent with this scenario (šćavničar, 1979; ivković et al., 2000; saftić et al., 2003; kovačić, 2004; kovačić et al., 2004, 2011; kovačić & grizelj, 2006; grizelj et al., 2007, 2017; pavelić & kovačić, 2018; špelić et al., 2023). the virtually identical detrital signatures in the sava depression and the drava depression indicate that the two depressions were connected within lake pannon during the late miocene, being part of the same dispersal system, possibly represented by the palaeo-sava and/or palaeo-drava rivers (fig. 12). the connection with the palaeo-danube remains uncertain (magyar et al., 2013; sebe et al., 2020) and in need of further provenance studies from the hungarian part of the pannonian basin. 6. conclusions the upper miocene feldspatho-litho-quartzose carbonaticlastic sandstones from the sava and drava depressions, that belong to the north croatian basin, include limestone, dolostone, mica schist, quartzite, gneiss, phyllite, and granitoid rock fragments. generally poor to moderately poorly preserved, transparent heavy-mineral assemblages are dominated by almandine-rich garnet, associated with epidote, staurolite, and zoisite sourced from low to medium-grade metamorphic source rocks. the low thmc index with a lack of ferromagnesian minerals and moderate amounts of durable zircon, tourmaline, and rutile, indicate the significant effects of selective diagenetic dissolution and of the addition of detritus recycled from older siliciclastic deposits. integrated petrographic, heavy-mineral, garnet raman spectroscopic, and geochemical signatures concur to indicate a major provenance from the eastern alps orogenic belt including the sedimentary, metamorphic, and igneous rocks of the austroalpine and penninic nappes. the late miocene uplift of the alps and subsidence of the pannonian basin created the conditions that led to massive fluvial sediment transfer from the orogen into lake pannon. the strikingly similar detrital signatures observed in both the sava and drava depressions suggest their shared origin within the lake’s depositional setting, characterized by the same sediment-dispersal system associated possibly with palaeo-sava and/or palaeo-drava rivers, following mainly the nw to se transport direction of detritus, which is also characteristic of the progradation system of the palaeo-danube but opposite to the system in the se part of the basin (radivojević et al., 2022). these insights, crucial for a better understanding of sedimentary processes and the geological evolution of the pannonian basin, offer a novel perspective to distinguish the upper miocene reservoirs from other sedimentary units within the basin and provide valuable information for the industry, i.e., future resource exploration and development also related to energy transition and environmental sustainability. despite the basin’s extensive exploration history, the reservoir properties of the sandstones remained relatively unexplored, highlighting the significance of this study the delineation of mineralogical and geochemical signatures enables improved reservoir characterization, facilitating chemo-stratigraphic assessment and prognosticative modeling in the subsurface. acknowledgement mario matošević’s phd scholarship is supported by the faculty of mining, geology and petroleum engineering, university of zagreb. the research forms part of the sedbas project funded by the croatian science foundation (ip-201904-7042). we extend our gratitude to the international association of sedimentologists (ias) for facilitating geochemical analyses through their support via the ias postgraduate research grant. special appreciation is expressed to ina (industrija nafte d.d.) for essential contribution to the research. our thanks also go to ljiljana kirin for assisting with sample preparation and adaleta perković for assisting with graphical representations. the authors acknowledge the valuable input from reviewers, dejan radivojević and an anonymous reviewer, whose constructive comments helped us to significantly improve the effectiveness of the manuscript. publication process is supported by the development fund of the faculty of mining, geology and petroleum engineering, university of zagreb. references aitchison, j. (1986): the statistical analysis of compositional data.– chapman and hall, london, 416 p. doi: 10.1007/978-94-009-4109-0 alcalde, j., heinemann, n., mabon, l., worden, r.h., de coninck, h., robertson, h., maver, m., ghanbari, s., swennenhuis, f., mann, i., walker, t., gomersal, s., bond, c.e., allen, m.j., haszeldine, r.s., james, a., mackay, e.j., brownsort, p.a., faulker, d.r. & murphy, s. (2019): acorn: developing full-chain industrial carbon capture and storage in a resourceand infrastructure-rich hydrocarbon province.– journal of cleaner production, 233, 963–971. doi: 10.1016/j.jcanlepro.2019.06.087 amorosi, a., sammartino, i., dinelli, e., campo, b., guercia, t., trincardi, f. & pellegrini, c. (2022): provenance and sediment dispersal in the po-adriatic source-to-sink system unraveled by bulk-sediment geochemistry and its linkage to catchment geology.– earth-science reviews, 104202. doi: 10.1016/j.earscirev.2022.104202 anđelković, f. & radivojević, d. (2021): the serbian lake pannon formations their significance and interregional correlation.– geološki anali balkanskog poluostrva, 82/2, 43–67. doi: 10.2298/gabp210420007a g eo lo gi a c ro at ic a 80 geologia croatica 77/2 arató r., obbágy, g., dunkl, i., józsa, s., lünsdorf, k., szepesi, j., molnár, k., benkó, z. & von eynatten, h. (2021): multi-method comparison of modern river sediments in the pannonian basin system – a key step towards understanding the provenance of sedimentary basin-fill.– global and planetary change, 199, 103446. doi: 10.1016/j.gloplacha.2021.103446 asch, k. (2003): the 1:5 million international geological map of europe and adjacent areas: development and implementation of a gis-enabled concept.– geological yearbook, sa 3, bgr, hannover, 172 p. aubrecht, r., meres, š., sykora, m. & mikuš, t. (2009): provenance of the detrital garnets and spinels from the albian sediments of the czorsztyn unit (pieniny klippen belt, western carpathians, slovakia).– geologica carpathica, 60/6, 463–483. doi: 10.2478/v10096-009-0034-z balázs, a., matenco, l., magyar, i., horváth, f. & cloe tingh, s. (2016): the link between tectonics and sedimentation in back-arc basins: new genetic constraints from the analysis of the pannonian basin.– tectonics, 35, 1526–1559. doi: 10.1002/2015tc004109 balázs, a. (2017): dynamic model for the formation and evolution of the pannonian basin: the link between tectonics and sedimentation.– utrecht stud. earth sciences, 132, 153. balázs, a., magyar, i., matenco, l., sztanó, o., tőkés, l. & horváth, f. (2018): morphology of a large palaeo-lake: analysis of compaction in the miocene-quaternary pannonian basin.– global and planetary change, 171, 134–147. doi: 10.1016/j.gloplacha.2017.10.012 báldi, t. (1980): a korai paratethys története.– földtani közlöny, 110, 456–472. basch, o., pavelić, d. & bakrač, k. (1995): gornjopontski facijesi sjevernog krila konjšćinske sinklinale kod huma zabočkog (hrvatsko zagorje).– in: vlahović, i., velić, i. & šparica, m. (eds.): first croatian geological congress, proceedings. institute of geology, croatian geological society, zagreb, 57–61. bersani, d., andò, s., vignola, p., moltifiori, g., marino, i.g., lottici, p.p. & diella, v. (2009): micro-raman spectroscopy as a routine tool for garnet analysis. spectrochimica acta part a: molecular and biomolecular spectroscopy, 73/3, 484–491. doi: 10.1016/j. saa.2008.11.033 bhatia, m. (1983): plate tectonics and geochemical composition of sandstones.– the journal of geology, 91, 611–627. doi: 10.1086/628815 bhatia, m. & crook, k.a.w. (1986): trace element characteristicsof graywackes and tectonic setting discrimination of sedimentary basins. contributions to mineralogy and petrology 92, 181–193. bigunac, d. (2022): depositional environments and subsurface settings of the lower miocene sediments in the slavonia-srijem, drava and sava depressions.– dissertation, faculty of mining, geology and petroleum engineering, university of zagreb. bousquet, r., oberhänsli, r., schmid, s.m., berger, a., wiederkehr, m., robert, c., möller, a., rosenberg, c., koller, f., molli, g. & zeilinger, g. (2012): metamorphic framework of the alps.– comision for the geological map of the world (ccgm/cgmw). boynton, w.v. (1984): cosmochemistry of the rare earth elements: meteorite studies.– in: henderson p. (ed.): rare earth element geochemistry.– elsevier, amsterdam, 63–114. doi: 10.1016/b978-0-44442148-7.50008-3 dickinson, w.r. (1985): interpreting provenance relations from detrital modes of sandstones.– in: zuffa g.g. (ed.): provenance of arenites.– reidel, dordrecht, nato asi series, 148, 333–361. doi: 10.1007/97894-017-2809-6_15 dolton, l.g. (2006): pannonian basin province, central europe (province 4808) – petroleum geology, total petroleum systems, and petroleum resource assessment.– u.s. geological survey, bulletin 2204-b. doi: 10.3133/b2204b egozcue, j.j., pawlowsky-glahn, v., mateu-figueras, g. & barcelo-vidal, c. (2003): isometric logratio transformations for compositional data analysis.– mathematical geology, 35/3, 279–300. doi: 10.1023/a:1023818214614 egozcue, j.j. & pawlowsky-glahn, v. (2005): coda-dendrogram: a new exploratory tool.– in: compositional data analysis workshop – codawork’05, proceedings, 1–10. garzanti, e., resentini, a., vezzoli, g., andò, s., malusà, m.g., padoan, m. & paparella, p. (2010): detrital fingerprints of fossil continental-subduction zones (axial belt provenance, european alps).– the journal of geology, 118/4, 341–362. doi: 10.1086/652720 garzanti, e., padoan, m., andò, s., resentini, a., vezzoli, g. & lustrino, m. (2013): weathering and relative durability of detrital minerals in equatorial climate: sand petrology and geochemistry in the east african rift.– the journal of geology, 121/6, 547–580. doi: 10.1086/673259 garzanti, e., padoan, m., setti, m., lópez-galindo, a. & villa, i.m. (2014): provenance versus weathering control on the composition of tropical river mud (southern africa).– chemical geology, 366, 61–74. doi: 10.1016/j.chemgeo.2013.12.016 garzanti, e. (2016): from static to dynamic provenance analysis – sedimentary petrology upgraded.– in: caracciolo, l., garzanti, e., von eynatten, h. & weltje, g.j. (eds.): sediment generation and provenance: processes and pathways.– sedimentary geology, 336, 3–13. doi: 10.1016/j.sedgeo.2015.07.010 garzanti, e. (2017): the maturity myth in sedimentology and provenance analysis.– journal of sedimentary research, 87/4, 353–365. doi: 10.2110/ jsr.2017.17 garzanti, e., andò, s., limonta, m., fielding, l. & najman, y. (2018): diagenetic control on mineralogical suites in sand, silt, and mud (cenozoic nile delta): implications for provenance reconstructions.– earth-science reviews, 185, 122–139. doi: 10.1016/j.earscirev.2018.05.010 garzanti, e. (2019): petrographic classification of sand and sandstone.– earth-science reviews, 192, 545–563. doi: 10.1016/j.earscirev.2018.12.014 grizelj, a., tibljaš, d. & kovačić, m. (2007): mineralogy and geochemistry of upper miocene pelitic sediments of zagorje basin (croatia): implications for evolution of pannonian basin.– geologica carpathica, 58/3, 263–276. grizelj, a., tibljaš, d., kovačić, m. & španić, d. (2011): diagenesis of miocene pelitic sedimentary rocks in the sava depression (croatia).– clay minerals, 46/1, 59–72. doi: 10.1180/claymin.2011.046.1.59 grizelj, a., peh, z., tibljaš, d., kovačić, m. & kurečić, t. (2017): mineralogical and geochemical characteristics of miocene pelitic sedimentary rocks from the south-western part of the pannonian basin system (croatia): implications for provenance studies.– geoscience frontiers, 8/1, 65–80. doi: 10.1016/j.gsf.2015.11.009 harzhauser, m., latal, c. & piller, w. (2007): the stable isotope archive of lake pannon as a mirror of late miocene climate change.– palaeogeography, palaeoclimatology, palaeoecology, 249, 335–350. doi: 10.1016/j.palaeo.2007.02.006 harzhauser, m. & piller, w.e. (2007): benchmark data of a changing sea – palaeogeography, palaeobiogeography and events in the central paratethys during the miocene.– palaeogeography, palaeoclimatology, palaeoecology, 253, 8–31. doi: 10.1016/j.palaeo.2007.03.031 harzhauser, m. & mandic, m. (2008): neogene lake systems of the central and south-eastern europe – faunal diversity, gradients and interrelations.– palaeogeography, palaeoclimatology, palaeoecology, 260, 417–434. doi: 10.1016/j.palaeo.2007.12.013 hauke, m., froitzheim, n., nagel, t.j., miladinova, i., fassmer, k., fonseca, r.o.c., sprung, p. & münker, c. (2019): two high-pressure metamorphic events, variscan and alpine, dated by lu–hf in an eclogite complex of the austroalpine nappes (schobergruppe, austria).– international journal of earth sciences (geol rundsch), 108, 1317–1331. doi: 10.1007/s00531-019-01708-8 horváth, f. (1993): towards a mechanical model for the formation of the pannonian basin.– tectonophysics, 226, 333–357. doi: 10.1016/00401951(93)90126-5 https://link.springer.com/article/10.1007/s00531-019-01708-8#auth-carsten-m_nker-aff3 g eologia c roatica 81matošević et al.: the alps as the main source of sand for the late miocene lake pannon (pannonian basin, croatia) horváth, f. (1995): phases of compression during the evolution of the pannonian basin and its bearing on hydrocarbon exploration.– marine and petroleum geology, 12, 837–844. doi: 10.1016/0264-8172(95)98851-u horváth, f., musitz, b., balázs, a., vegh, a., uhrin, a., nador, a., koroknai, b., pap, n., toth, t. & worum, g. (2015): evolution of the pannonian basin and its geothermal resources.– geothermics, 53, 328–352. doi: 10.1016/j.geothermics.2014.07.009 hubert, j.f. (1962): a zircon-tourmaline-rutile maturity index and the interdependence of the composition of heavy mineral assemblages with the gross composition and texture of sandstones.– journal of sedimentary research, 323, 440–450. doi: 10.1306/74d70ce5-2b21-11d78648000102c1865d ivković, ž., matej, s. & škoko, m. (2000): seismostratigraphic interpretation of upper miocene and pliocene sediments of the sava depression.– in: vlahović i. & biondić r. (eds.): second croatian geological congress, proceedings, zagreb, 219–222. jamičić, d. (1995): the role of sinistral strike-slip faults in the formation of the structural fabric of the slavonian mts. (eastern croatia).– geologia croatica, 48, 155–160. janák, m., froitzheim, n., lupták, b., vrabec, m. & ravna, e.j.k. (2004): first evidence for ultrahigh‐pressure metamorphism of eclogites in pohorje, slovenia: tracing deep continental subduction in the eastern alps.– tectonics, 23/5. doi: 10.1029/2004tc001641 janoušek, v., farrow, c.m. & erban, v. (2006): interpretation of whole-rock geochemical data in igneous geochemistry: introducing geochemical data toolkit (gcdkit).– journal of petrology, 47/6, 1255– 1259. doi: 10.1093/petrology/egl013 juhász, gy. (1994): comparison of the sedimentary sequences in late neogene subbasins in the pannonian basin, hungary [magyarországi neogén medencerészek pannóni ai s.l. üledéksorának összehasonlító elemzése – in hungarian].– földtani közlöny 124/4, 341–365. karampelas, s., hennebois, u., bersani, d., delaunvay, a. & fritsch, e. (2023): disambiguation of pyrope-rich garnet inclusions in coloured sapphires from tanzania and identification of other inclusions by raman spectroscopy.– journal of raman spectroscopy, 54/11, 1213–1219. doi: 10.1002/jrs.6570 kolenković močilac, i., cvetković, m., saftić, b. & rukavina, d. (2022): porosity and permeability model of a regional extending unit (upper miocene sandstones of the western part of sava depression, croatia) based on vintage well data.– energies, 15, 6066. doi: 10.3390/ en15166066 kováč, m., nagymarosy, a., oszczypko, n., slaczka, a., csontos, l., marunteanu, m., matenco, l. & márton, m. (1998): palinspastic reconstruction of the carpathian pannonian region during the miocene.– in: rakús m. (ed.): geodynamic development of the western carpathians. geol. survey of slovak republic, bratislava, 189–217. kováč, m., márton, e., oszczypko, n., vojtko, r., hók, j., králiková, s., plašienka, d., klučiar, t., hudáčková, n. & oszczypko-clowes, m. (2017): neogene palaeogeography and basin evolution of the western carpathians, northern pannonian domain and adjoining areas.– global and planetary change, 155, 133–154. doi: 10.1016/j.gloplacha.2017.07.004 kováč, m., halásová, e., hudáčková, n., holcová, k., hyžný, m., jamrich, m. & ruman, a. (2018): towards better correlation of the central paratethys regional time scale with the standard geological time scale of the miocene epoch.– geologica carpathica, 69/3, 283–300. doi: 10.1515/geoca-2018-0017 kovačić, m. (2004): sedimentologija gornjomiocenskih naslaga jugozapadnog dijela panonskog bazena [sedimentology of the upper miocene deposits from the south-western part of pannonian basin – in croatian with an english summary].– unpubl. phd. thesis, university of zagreb, 203 p. kovačić, m., zupanič, j., babić, l., vrsaljko, d., miknić, m., bakrač, k., hećimović, i., avanić, r. & brkić, m. (2004): lacustrine basin to delta evolution in the zagorje basin, a pannonian sub-basin (late miocene: pontian, nw croatia).– facies, 50/1, 19–33. kovačić, m. & grizelj, a. (2006): provenance of the upper miocene clastic material in the southwestern pannonian basin.– geologica carpathica, 57, 495–510. kuhlemann, j., frisch, w., székely, b., dunkl, i. & kázmér, m. (2002): post-collisional sediment budget history of the alps: tectonic versus climatic control.– international journal of earth sciences, 91/5, 818–837. doi: 10.1007/s00531-002-0266-y lawan, a.y., worden, r.h., utley, j.e.p. & crowley, s.f. (2021): sedimentological and diagenetic controls on the reservoir quality of marginal marine sandstones buried to moderate depths and temperatures: brent province, uk north sea.– marine and petroleum geology, 128, 104993. doi: 10.1016/j.marpetgeo.2021.104993 lučić, d., saftić, b., krizmanić, k., prelogović, e., britvić, v., mesić, i. & tadej, j. (2001): the neogene evolution and hydrocarbon potential of the pannonian basin in croatia.– marine and petroleum geology, 18, 133–147. doi: 10.1016/s0264-8172(00)00038-6 macenić, m., kurevija, t. & medved, i. (2020): novel geothermal gradient map of the croatian part of the pannonian basin system based on data interpretation from 154 deep exploration wells.– renewable and sustainable energy reviews, 132, 110069. doi: 10.1016/j.rser.2020.110069 magyar, i., geary, d.h. & müller, p. (1999): palaeogeographic evolution of the late miocene lake pannon in central europe.– palaeogeography, palaeoclimatology, palaeoecology, 147, 151–167. doi: 10.1016/ s0031-0182(98)00155-2 magyar, i., radivojević, d., sztanó, o., synak, r., ujszászi, k. & pócsik, m. (2013): progradation of the palaeo-danube shelf margin across the pannonian basin during the late miocene and early pliocene.– global and planetary change, 103, 168–173. doi: 10.1016/j.gloplacha.2012.06.007 magyar, i. (2021): chronostratigraphy of clinothem-filled non-marine basins: dating the pannonian stage.– global and planetary change, 205, 103609. doi: 10.1016/j.gloplacha.2021.103609 malvić, t. & velić, j. (2011): neogene tectonics in croatian part of the pannonian basin and reflectance in hydrocarbon accumulations.– in: schattner u. (ed.): new frontiers in tectonic research: at the midst of plate convergence.– intech, rijeka, 215–238. mandic, o., kurečić, t., neubauer, t.a. & harzhauser, m. (2015): stratigraphic and palaeogeographic significance of lacustrine molluscs from the pliocene viviparus beds in central croatia.– geologia croatica, 68, 179–207. doi: 10.4154/gc.2015.15 mange, m.a. & maurer, h.f.w. (1992): heavy mineral in colour. – chapman and hall, london 147 p. mange, m.a & morton, a.c. (2007): geochemistry of heavy minerals.– in: mange, m.a & wright, d.t. (eds): heavy minerals in use. developments in sedimentology series, 58, 345–391. doi: 10.1016/s00704571(07)58013-1 martín-fernández, j.a., horn, k., templ, m., filzmoser, p. & palarea-albaladejo, j. (2015): bayesian-multiplicative treatment of count zeros in compositional data sets.– statistical modelling, 15/2, 134–158. doi: 10.1177/1471082x14535524 márton, e., pavelić, d., tomljenović, b., pamić, j. & márton, p. (1999): first palaeomagnetic results on ternary rocks from the slavonian mountains in the southern pannonian basin, croatia.– geologica carpathica, 50/3, 273–279. márton, e., pavelić, d., tomljenović, b., avanić, r., pamić, j. & márton, p. (2002): in the wake of a counterclockwise rotating adriatic microplate: neogene palaeomagnetic results from northern croatia.– international journal of earth sciences, 91/3, 514–523. doi: 10.1007/s00531-001-0249-4 matenco, l.c. & radivojević, d. (2012): on the formation and evolution of the pannonian basin: constraints derived from the structure of the junction area between the carpathians and dinarides.– tectonics, 31/6. doi: 10.1029/2012tc003206 g eo lo gi a c ro at ic a 82 geologia croatica 77/2 matošević, m., marković, f., bigunac, d., šuica, s., krizmanić, k., perković, a., kovačić, m. & pavelić, d. (2023): petrography of the upper miocene sandstones from the north croatian basin: understanding the genesis of the largest reservoirs in the southwestern part of the pannonian basin system.– geologica carpathica, 74/2, 155– 179. doi: 10.31577/geolcarp.2023.06 mclennan, s.m., hemming, s., mcdaniel, d.k. & hanson, g.n. (1993): geochemical approaches to sedimentation, provenance, and tectonics.– geological society of america special paper, 284, 21–40. doi: 10.1130/spe284-p21 mencin gale, e., jamšek rupnik, p., trajanova, m., gale, l., bavec, m., anselmetti, f.s. & šmuc, a. (2019a): provenance and morphostratigraphy of the pliocene-quaternary sediments in the celje and drava-ptuj basins (eastern slovenia).– geologija, 62/2, 189–218. doi: 10.5474/geologija.2019.009 mencin gale, e., jamšek rupnik, p., trajanova, m., bavec, m., anselmetti, f.s. & šmuc, a. (2019b): morphostratigraphy and provenance of plio‐pleistocene terraces in the south‐eastern alpine foreland: the mislinja and upper savinja valleys, northern slovenia.– journal of quaternary science, 34/8, 633–649. doi: 10.1002/jqs.3156 morton, a.c. & hallsworth, c. (2007): stability of detrital heavy minerals during burial diagenesis.– developments in sedimentology, 58, 215–245. doi: 10.1016/s0070-4571(07)58007-6 nesbitt, h.w. & young, g.m. (1982): early proterozoic climates and plate motions inferred from major element chemistry of lutites.– nature, 299, 715–717. doi: 10.1038/299715a0 novak zelenika, k., malvić, t. & geiger, j. (2010): mapping of the late miocene sandstone facies using indicator kriging.– nafta, 61/5, 225–233. pamić, j. (1986): magmatic and metamorphic complexes of the adjoining area of the northernmost dinarides and pannonian mass.– acta geologica hungarica, 29, 203–220. pamić, j. (1999): kristalinska podloga južnih dijelova panonskog bazena – temeljena na površinskim i bušotinskim podacima.– nafta, 50/9, 291–310. pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.– basin research, 13, 359–376. doi: 10.1046/j.0950-091x.2001.00155.x pavelić, d. & kovačić, m. (2018): sedimentology and stratigraphy of the neogene rift-type north croatian basin (pannonian basin system, croatia): a review.– marine and petroleum geology, 91, 455–469. doi: 10.1016/j.marpetgeo.2018.01.026 pawlowsky-glahn, v., egozcue, j.j. & lovell, d. (2015): tools for compositional data with a total.– statistical modelling, 15/2, 175–190. doi: 10.1177/1471082x14535526 pettijohn, f.j., potter, p.e. & siever, r. (1987): sand and sandstone.– 2nd edition, springer, new york, 553 p. doi: 10.1007/978-1-46121066-5 piller, w., harzhauser, m. & mandic, o. (2007): miocene central paratethys stratigraphy – current status and future directions.– stratigraphy, 4, 151–168. doi: 10.29041/strat.04.2.09 razum, i., lužar-oberiter, b., zaccarini, f., babić, l., miko, s., hasan, o., ilijanić, n., beqiraj, e. & pawlowskyglahn, v. (2021): new sediment provenance approach based on orthonormal log ratio transformation of geochemical and heavy mineral data: sources of eolian sands from the southeastern adriatic archipelago.– chemical geology, 583, 120451. doi: 10.1016/j.chemgeo.2021.120451 razum, i., rubinić, v., miko, s., ružičić, s. & durn, g. (2023): coherent provenance analysis of terra rossa from the northern adriatic based on heavy mineral assemblages reveals the emerged adriatic shelf as the main recurring source of siliciclastic material for their formation.– catena, 226, 107083. doi: 10.1016/j.catena.2023.107083 rögl, f. & steininger, f.f. (1983): vom zerfall der tethys zu mediterran und paratethys. die neogene palaeogeographie und palinspastik des zirkum-mediterranen raumes.– annalen des naturhistorischen museum in wien, 85 a, 135–163. rögl, f. (1998): palaeogeographic considerations for mediterranean and paratethys seaways (oligocene to miocene).– annalen des naturhistorischen museum in wien, 99 a, 279–310. roser, b.p. & korsch, r.j. (1988): provenance signatures of sandstone -mudstone suites using discriminant function analysis of major-element dana. chemical geology 67, 119–139. royden, l.h. (1988): late cenozoic tectonics of the pannonian basin system.– in: royden l.h. & horváth f. (eds.): the pannonian basin: a study in basin evolution. aapg memoir, 45, 27–48. doi: 10.1306/ m45474c3 rukavina, d., saftić, b., matoš, b., kolenković močilac, i., premec fuček, v. & cvetković, m. (2023): tectonostratigraphic analysis of the syn-rift infill in the drvaa basin, southwestern pannonian basin system.– marine and petroleum geology, 152, 106235. doi: 10.1016/j.marpetgeo.2023.106235 saftić, b., velić, j., sztanó, o., juhász, gy. & ivković, ž. (2003): tertiary subsurface facies, source rocks and hydrocarbon reservoirs in the sw part of the pannonian basin (northern croatia and south-western hungary).– geologia croatica, 56, 101–122. schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine-carpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss journal of geosciences, 101, 139–183. doi: 10.1007/s00015-008-1247-3 schmid, s.m., fügenschuh, b., kounov, a., matenco, l., nievergelt, p., oberhänsli, r., pleuger, j., schefer, s., schuster, r., tomljenović, b., ustaszewski, k. & van hinsbergen, d.j.j. (2020): tectonic units of the alpine collision zone between eastern alps and western turkey.– gondwana research, 78, 308–374. doi: 10.1016/j.gr.2019.07.005 šćavničar, b. (1979): pješčenjaci pliocena i miocena savske potoline (sandstones of the pliocene and miocene age in the sava river depression).– zbornik radova 3. god. naučni skup sekcije za primjenu geol. geofiz. geokem. znan. savjeta za naftu, novi sad (1977), 2, 351–382. schuster, r., kurz, w., krenn, k. & fritz, h. (2013): introduction to the geology of the eastern alps.– berichte de geologischen bundes-anstalt wien, 99, 121–133. sebe, k., kovačić, m., magyar, i., krizmanić, k., špelić, m., bigunac, d., sütő-szentai, m., kovács, á., szuromi-korecz, a., bakrač, k., hajek-tadesse, v., troskot-čorbić, t. & sztanó, o. (2020): correlation of upper miocene-pliocene lake pannon deposits across the drava basin, croatia and hungary.– geologia croatica, 73/3, 177–195. doi: 10.4154/gc.2020.12 sneider, r.m. (1990): reservoir description of sandstones.– in: barwis j.h., mcpherson j.g. & studlick j.r.j. (eds.): sandstone petroleum reservoirs. casebooks in earth sciences. springer, new york, 1–3. doi: 10.1007/978-1-4613-8988-0_1 steininger, f.f. & rögl, f. (1979): the paratethys history – a contribution towards the neogene geodynamics of the alpine orogene (an abstract).– ann. géol. pays hellén., tome hors serie, fasc. iii, 1153–1165, athens. sztanó, o., szafián, p., magyar, i., horányi, a., bada, g., hughes, d.w., hoyer, d.l. & wallis, r.j. (2013): aggradation and progradation controlled clinothems and deepwater sand delivery model in the neogene lake pannon, makó trough, pannonian basin, se hungary.– global and planetary change, 103, 149–167. doi: 10.1016/j.gloplacha.2012.05.026 sztanó, o., sebe, k., csillag, g. & magyar, i. (2015): turbidites as indicators of palaeotopography, upper miocene lake pannon, western mecsek mountains (hungary).– geologica carpathica, 66, 331–344. doi: 10.1515/geoca-2015-0029 špelić, m., kovács, á., saftić, b. & sztanó, o. (2023): competition of deltaic feeder systems reflected by slope progradation: a high-resolution example from the late miocene-pliocene, drava basin, croatia.– international journal of earth sciences, 112, 1023–1041. doi: 10.1007/ s00531-023-02290-w https://www.researchgate.net/profile/orsolya-sztano?_sg%5b0%5d=iltbnhq0acl85kcdh12y9fmwyoub4t9y1gxe7pgkgrtowe2sna5pjdwt_gpamyhfoxyps4u.mlb6oasbmm7im58f3hcvbz4vk6kayoyl5d3ddykcxeqo3jzosjfmyhwsk4ck7zdyjweivplba45k4ftyyj4xsq&_sg%5b1%5d=yznwshjdh5p_exoqio9v1zaqcti_iskk9yokztnefn4gzrelzkmwiuayzu1zdsg8-uc-pts.48c84oh8kmfph35z3yg6byizatdzcrclx3-u1ap8xfdqrmqd-bgz-m7g9phmkinupqsp8i6ysbb-jfxafxnvmw&_tp=eyjjb250zxh0ijp7imzpcnn0ugfnzsi6inb1ymxpy2f0aw9uiiwicgfnzsi6inb1ymxpy2f0aw9uiiwichjldmlvdxnqywdlijoichjvzmlszsisinbvc2l0aw9uijoicgfnzuhlywrlcij9fq g eologia c roatica 83matošević et al.: the alps as the main source of sand for the late miocene lake pannon (pannonian basin, croatia) šuica, s., garašić, v. & woodland, a.b. (2022a): petrography and geochemistry of granitoids and related rocks from the pre-neogene basement of the slavonia–srijem depression (croatia).– geologia croatica, 75, 129–144. doi: 10.4154/gc.2022.09 šuica, s., tapster, s.r., mišur, i. & trinajstić, n. (2022b): the late cretaceous syenite from the sava suture zone (eastern croatia).– in: xxii international congress of the cbga, plovdiv, bulgaria, 7–11 september 2022, abstracts, 100. tari, g., horváth, f. & rumpler, j. (1992): styles of extension in the pannonian basin.– tectonophysics, 208, 203–219. https://doi. org/10.1016/0040-1951(92)90345-7 taylor, s.r. & mclennan, s.m. (1985): the continental crust: its composition and evolution.– blackwell science, oxford, 315 p. ter borgh, m., vasiliev, i., stoica, m., knežević, s., matenco, l., krijgsman, w., rundić, lj. & cloetingh, s. (2013): the isolation of the pannonian basin (central paratethys): new constrains from magnetostratigraphy and biostratigraphy.– global and planetary change, 103, 99–118. doi: 10.1016/j.gloplacha.2012.10.001 tomljenović, b. & csontos, l. (2001): neogene-quaternary structures in the border zone between alps, dinarides and pannonian basin (hrvatsko zagorje and karlovac basins, croatia).– international journal of earth sciences, 90, 560–578. doi: 10.1007/s005310000176 tuschl, m., kurevija, t., krpan, m. & macenić, m. (2022): overview of the current activities related to deep geothermal energy utilisation in the republic of croatia.– clean technologies and environmental policy, 24, 3003–3031. doi: 10.1007/s10098-022-02383-1 velić, j., malvić, t., cvetković, m. & vrbanac, b. (2012): reservoir geology, hydrocarbon reserves and production in the croatian part of the pannonian basin system.– geologia croatica, 65, 91–101. doi: 10.4154/gc.2012.07 vermeesch, p., resentini, a. & garzanti, e. (2016): an r package for statistical provenance analysis.– sedimentary geology, 336, 14–25. doi: 10.1016/j.sedgeo.2016.01.009 vermeesch, p. (2018): statistical models for point-counting data.– earth and planetary science letters, 501, 112–118. doi:10.1016/j.epsl.2018.08.019 vrbanac, b., velić, j. & malvić, t. (2010): sedimentation of deep-water turbidites in the sw part of the pannonian basin.– geologica carpathica, 61/1, 55–69. doi: 10.2478/v10096-010-0001-8 worden, r.h., mayall, m.j. & evans, i.j. (1997): predicting reservoir quality during exploration: lithic grains, porosity and permeability in tertiary clastic rocks of the south china sea basin.– geological society of london, special publications, 126, 107–115. doi: 10.1144/gsl. sp.1997.126.01.08 worden, r.h. & burey, s.d. (2003): sandstone diagenesis: the evolution of sand to stone.– in: burley, s.d & worden, r.h. (eds.): sandstone diagenesis: recent and ancient.– international association of sedimentologists, 4, 3–44. worden, r.h., armitage, p.j., butcher, a.r., churchill, j.m., csoma, a.e., hollis, c., lander, r.h. & omma, j.e. (2018): petroleum reservoir quality prediction: overview and contrasting approaches from sandstone and carbonate communities.– geological society of london, special publications, 435, 1–31. doi: 10.1144/sp435.21 electronic supplementary material is available online at http://www.geologia-croatica.hr/index.php/gc/article/view/1198/1953 https://doi.org/10.1016/0040-1951(92)90345-7 https://doi.org/10.1016/0040-1951(92)90345-7 http://www.geologia-croatica.hr/index.php/gc/article/view/1198/1953 www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2025 | 78/1 | 1–14 | 4 figs. | 1 tab. | 4 plts. | 1. introduction the northern calcareous alps have a complex mesozoic– cenozoic tectono-stratigraphic history and experienced seve ral mountain building processes. the first phase is the middle– late jurassic ophiolite obduction in the frame of the formation of the neotethyan belt (missoni & gawlick, 2011a, b), which is followed by “mid-cretaceous” orogenesis (tollmann, 1985; janák et al., 2004; schmid et al., 2004). after that the true alpine mountain building process occurred (handy et al., 2010 and references therein), with collision of the austroalpine unit as the northern part of the wider adria plate (gawlick & missoni, 2019) with europe (faupl & wagreich, 2000), and the subsequent lateral tectonic extrusion since miocene times (ratschbacher et al., 1991). therefore, the northern calcareous alps presently consist of several nappes that were differentiated into, and in some cases rotated blocks, by cenozoic faults and fault zones (linzer et al., 1995; frisch & gawlick, 2003; pueyo et al., 2007). during these polyphase mountain-building processes the original facies belts of the triassic–middle jurassic passive continental margin configuration were completely destroyed in parts. the outer shelf area (hallstatt shelf) can only be reconstructed by the analysis of reworked material in various mélanges (e.g., hallstatt mélange, defined by frisch & gawlick (2003); haselgebirge mélange defined by spötl et al. (1998)), and by a comparison with other mountain chains in the western tethyan realm (e.g., western carpathians, southern alps, dinarides, albanides, early jurassic radiolarians from the weitenau area (northern calcareous alps, austria) and their implications for palaeogeography tim cifer1,*, hans-jürgen gawlick2 & oliver krische3 1 research centre of the slovenian academy of sciences and arts, ivan rakovec institute of palaeontology novi trg 2, ljubljana 1000, slovenia; (corresponding author: tim.cifer@zrc-sazu.si) 2 montanuniversität leoben, energy geosciences, peter-tunner-straße 5, 8700 leoben, austria; (hans-juergen.gawlick@unileoben.ac.at) 3 haritzmeierstraße 12, 8605 parschlug, austria; (oliver_krische@gmx.at) doi: 10.4154/gc.2025.01 abstract the lower jurassic sedimentary sequence deposited on the outer shelf (hallstat shelf) of the neo-tethys passive margin occurs mainly as blocks in different mélanges, or in rare cases, far-travelled nappes formed in the frame of the middle–late jurassic mountain building process related to ophiolite obduction. datable lower jurassic blocks are very rare in the western tethyan realm, and are studied in detail for their age and sedimentological characteristics in order to reconstruct the jurassic distal parts of the neo-tethyan passive continental margin. one of these exotic blocks, belonging to the marly siliceous limestones of the dürrnberg formation, was discovered in the haselgebirge mélange of the weitenau area (northern calcareous alps, austria). the block yielded a well-preserved radiolarian fauna, which is assigned here to the uppermost lower pliensbachian gigi fustis–lantus sixi radiolarian zone. the occurrence of this lower jurassic block beside other exotic blocks in the upper jurassic haselgebirge mélange proves the allochthony of the haselgebirge mélange in the weitenau area. hellenides and units in the pannonian realm; gawlick & missoni, 2019 and references therein). while the triassic sedimentological history of the different hallstatt facies belts is fairly well understood (lein, 1987; krystyn, 2008) the early–middle jurassic depositional history is, except for some details, mostly enigmatic (gawlick et al., 2009 and references therein), due to the lack of datable blocks in different mélanges around the neotethyan belt. in fact, datable lower jurassic successions that derive from the outer (distal) shelf are at the moment only known from such mélanges in the northern calcareous alps (hallstat mélange and haselgebirge mélange). the eastern alps, including the northern calcareous alps, were palaeogeographically situated in a relatively central position (gawlick & missoni, 2019) of the west-northwest striking passive continental margin spanning from the hellenides to the western carpathians. to unravel the early jurassic outer (hallstatt) shelf history of the northern calcareous alps, it is important to study all the available blocks in these differentiated areas in terms of age, facies and depositional environment, to achieve a convincing early jurassic outer shelf reconstruction and depositional history for the whole western tethyan realm. radiolarians, besides the rare ammonoids, are usually the only available biostratigraphic tool to determine the age of these exotic blocks, and they have been widely applied in past tectono-stratigraphic studies and palaeogeographic reconstructions of the northern calcareous alps (e.g., gawlick et al., 2007; auer et al., 2009; gawlick et al., 2009). article history: manuscript received: april 09, 2024 revised manuscript accepted: october 01, 2024 available online: january 30, 2025 keywords: jurassic, pliensbachian, radiolarian biostratigraphy, eastern alps, palaeogeography, tethys g eo lo gi a c ro at ic a 2 geologia croatica 78/1 although well-preserved early jurassic radiolarian assem blages are rare, they are prerequisite for extensive and detailed taxonomic studies, which are the basis for precise age determinations. the best-preserved early jurassic assemblages in the western tethyan realm, and globally, were studied from pliensbachian limestones in turkey (pessagno & poisson, 1981; de wever, 1981a, b, 1982a, b) and from sinemurian– pliensbachian limestones in austria (o’dogherty & gawlick, 2008; cifer et al., 2020, 2022; cifer & goričan, 2023a, b). other studies from the western tethyan realm are from italy (bertinelli & marcucci, 2011), slovenia (goričan et al., 2003), austria (kozur & mostler, 1990; gawlick et al., 2001), greece (chiari et al., 2013), cyprus (bragin et al., 2022), and turkey (tekin, 2002; tekin et al., 2020). radiolarians generally radiate extremely fast and are globally abundant, but there are still major differences between the radiolarian assemblages of different provinces (the western tethyan realm, panthalassa, the boreal and the austral realm). many age-diagnostic species, important for the lower jurassic global radiolarian zonation (carter et al., 2010) are either not abundant or are completely missing in the western tethyan realm (goričan et al., 2013). therefore, each well-preserved early jurassic radiolarian assemblage from the western tethyan realm provides new important data on radiolarian taxonomy and biostratigraphy, further enhancing the use of radiolarians as an age diagnostic and palaeobiogeographical tool. in this study we present the radiolarian inventory and a precise age assignment of a well-preserved radiolarian fauna collected from an exotic block in the weitenau area in the central northern calcareous alps (austria), with the aim of providing new information on the age and distribution of early jurassic radiolarian species of the western tethyan realm, and to define the palaeogeographic provenance and the tectono-stratigraphic evolution of the radiolarian bearing block, which was incorporated in the haselgebirge mélange. 2. geological overview the weitenau area lies in the central part of the northern calcareous alps (figs. 1a, b) and belongs the tirolic mega-unit. it consists predominantly of uppermost jurassic to lower cretaceous sedimentary rocks of the oberalm, schrambach and rossfeld formations (plöchinger, 1987, 1990), with several windows made of the upper jurassic haselgebirge mélange, which is, according to spötl et al. (1998), a mixture of upper permian–lowermost triassic gypsum matrix (haselgebirge formation of grubach moosege; schorn & neubauer, 2011; krische et al., 2013a) and various exotic components of permian to jurassic age (kirchner, 1980; von eynatten & gaupp, 1999; von eynatten et al., 1996; neubauer et al., 2007; schorn et al., 2013). these components are limestone blocks and volcanics, occa sionally with blue amphiboles indicating high-pressure/low temperature metamorphism (kirchner, 1980). limestone blocks from the weitenau area have not been previously studied unlike the limestone blocks in the berchtesgaden or hallein-bad dürrnberg salt mines (gawlick et al., 2009; missoni & gawlick, 2011a). the haselgebirge mélange in the weitenau area is part of the widespread occurring haselgebirge mélange in the central northern calcareous alps (tollmann, 1985), forming the important salt and gypsum deposits, which have been variously exploited for more than 3000 years. the emplacement history of the haselgebirge mélange in the sense of spötl et al. (1998) is rather complicated and poly phase. after formation of the different hallstatt mélanges in bathonian to oxfordian times (see gawlick & missoni, 2019 and references therein), the haselgebirge mélange was emplaced above the hallstatt mélanges and sealed by the latest oxfordian to kimmeridgian deepto shallow-water limestones of the plassen carbonate platform (gawlick & schlagint weit, 2006; gawlick et al., 2009, 2012; missoni & gawlick, 2011a, b). this is in line with the component spectrum in the various hallstatt mélanges of the northern calcareous alps, in which clasts of the latest permian to earliest triassic haselgebirge formation are missing. the first reworked clasts of the haselgebirge formation appear in the latest oxfordian to kimmeridgian sillenkopf formation (missoni et al., 2001). later, during tithonian times, the haselgebirge mélange was remobilized and transported further to the north to the oberalm formation (plöchinger, 1974, 1976, 1979; tollmann, 1985; bujtor et al., 2013). at the contact between the gypsum (haselgebirge mélange) and the uppermost jurassic to lower cretaceous sedimentary sequence (oberalm, schrambach and rossfeld formations), upper kimmeridgian–lower tithonian saccocoma lime stones are preserved. they limit the time of early emplacement of the haselgebirge mélange, before its reworking into the oberalm formation, to be above the callovian–oxfordian hallstatt mélange (fig. 2; krische et al., 2013a). the sacco­ coma limestones were originally deposited above the haselgebirge mélange and seal its first emplacement around the oxfordian–kimmeridgian boundary. this early emplacement age of the alpine haselgebirge mélange (spötl et al., 1998) is in line with data obtained in the salzkammergut (rötelstein – steiger & wurm, 1980; altausee – gawlick et al., 2012; hallstatt – gawlick & schlagintweit, 2006; krahstein – schlagintweit et al., 2003) or in the salzburg-berchtesgaden calcareous alps (berchtesgaden and bad dürrnberg – missoni & gawlick, 2011b). in the late triassic, the weitenau area was part of the huge hauptdolomite-dachstein carbonate platform and situated in the transitional facies zone between the restricted area (hauptdolomite) and the open lagoon (lagoonal dachstein limestone). in the late norian to rhaetian, the kössen basin as a deepened lagoon was formed due to siliciclastic input with its maximal extent in the late norian. in the early rhaetian, reefs established at the southern rim of the kössen basin and prograded rapidly northwards during the rhaetian. south of the rhaetian reefs, the lagoonal dachstein limestones were formed. only the relatively small eiberg basin (golebiowski, 1991) remained as a deeper area. the biotic crisis at the triassic–jurassic boundary (sepkoski, 1996; pálfy, 2008), combined with a sea-level fall (hubbard & boutler, 2000; guex et al., 2004), stopped the shallow-water carbonate production in the northern calcareous alps and led to the demise of the hauptdolomite-dachstein carbonate platform g eologia c roatica 3cifer et al.: early jurassic radiolarians from the weitenau area (northern calcareous alps, austria) and their implications for palaeogeography (gawlick et al., 1999; hillebrandt & krystyn, 2009). deposition during hettangian–pliensbachian times followed the palaeotopography of the uppermost triassic. on morphological highs, red nodular limestones of the hettangian to aalenian adnet group were deposited whereas in the basins, (i.e. the eiberg basin) grey siliceous limestones accumulated (böhm, 1992). the only exception is a smallscale basin at the northern edge of today’s tennengebirgehagengebirge block (fig. 1b), where locally condensed grey siliceous limestones (gawlick et al., 2009; gawlick & missoni, 2013) with a characteristic lithoand microfacies were deposited (gawlick et al., 2009). after a long-lasting figure 1. a) a tectonic sketch map of the eastern alps and study area (marked by the red box; fig. 1b) in the central northern calcareous alps (after tollmann, 1977; frisch & gawlick, 2003, modified). gpu graz palaeozoic unit; gu gurktal unit; gwz greywacke zone; rfz rhenodanubian flysch zone. b) the recent block configuration of the upper jurassic tirolic knappes in the central northern calcareous alps with major faults during miocene lateral tectonic extrusion (simplified and modified after frisch & gawlick, 2003). the studied locality of weitenau (hochreith unit according to krische et al., 2013a) northeast of golling is marked by a red star. g eo lo gi a c ro at ic a 4 geologia croatica 78/1 gap in the bajocian, deposition of the extremely condensed red nodular limestones of the klaus formation began (gawlick et al., 2009 for a summary and references) in the area of the southern osterhorn block and the tennengebirge-hagengebirge block (figs. 1b, 2). these bositraand protoglobigerina limestones (klaus formation) are overlain by callovian to oxfordian radiolarites, which later also form the matrix in the newly formed trench-like basins in front of the propagating thrust belt (hallstatt mélanges; gawlick & missoni, 2019 for an overview and references) that were triggered by ophiolite obduction. the alpine haselgebirge formation, was deposited around the permian–triassic boundary in the area below the future hallstatt shelf (tollmann, 1985). later, after the partial detachment of the siliciclastic lower triassic sequence and the uppermost lower triassic to middle jurassic open-shelf sequence, it acts as a basal thrust plane for the obducting ophiolites. during this process, blocks of the underlying sequence were scraped off and incorporated into the haselge birge mélange, similar to other mélanges elsewhere (schmid et al., 2008; festa et al., 2016). these exotic blocks of the haselgebirge mélange also belong to the lower jurassic figure 2. jurassic to early cretaceous stratigraphic table of the northern calcareous alps with the main tectonic middle–late jurassic events and lithostratigraphic names of the jurassic–early cretaceous of the northern calcareous alps (modified after gawlick & missoni, 2019). the early–middle jurassic depositional environment follows the late triassic topographic inventory of the hauptdolomite-dachstein carbonate platform formed of the passive continental margin of the neo-tethys ocean to the south, according to the present-day position of the northern calcareous alps. in the frame of obduction of neo-tethys derived ophiolites a northward propagating thrust belt formed since middle jurassic times. the obducting ophiolites were scraped off the late permian evaporites and blocks from the continental margin to the outer shelf (position 1) and transported this haselgebirge mélange (spötl et al., 1998) to the north until the late oxfordian (position 2; for a detailed explanation see missoni & gawlick, 2011a, b). during the tithonian, in the frame of mountain uplift and unroofing, the haselgebirge mélange was remobilized and transported further to the north (position 3; plöchinger, 1976) and then sealed by the lower cretaceous rossfeld basin fill (krische et al., 2014; krische & gawlick, 2015). tectonic motions, related to the lateral tectonic extrusion (ratschbacher et al., 1991; linzer et al., 1995; pueyo et al., 2007), led to remobilization of the alpine haselgebirge mélange and also formed the hochreith unit, which contains the alpine haselgebirge mélange in the weitenau area (krische et al., 2013a). hsm – haselgebirge mélange. g eologia c roatica 5cifer et al.: early jurassic radiolarians from the weitenau area (northern calcareous alps, austria) and their implications for palaeogeography marly-siliceous dürrnberg formation and to the toarcian– aalenian birkenfeld formation (gawlick et al., 2009; missoni & gawlick, 2011a, b). during this process, the alpine haselgebirge mélange experienced a low-grade thermal overprint during oxfordian and early kimmeridgian times (spötl et al., 1998). later, in the frame of the latest jurassic mountain uplift and unroofing (fig. 2), parts of the alpine haselgebirge mélange glided northwards and were incor porated in the tithonian oberalm formation (plöchinger 1974, 1976; krische et al., 2018) and sealed by the lower cretaceous sedimentary succession (schrambach and rossfeld formations; krische et al., 2013b, 2014). this tectonostratigraphic evolution is also documented in the area east– northeast of golling (fig. 1b; plöchinger, 1979). the lower jurassic marly siliceous limestone block, east of the berggasthof hochreith (fig. 3) described here, is one of these exotic blocks transported to the actual position by the early emplacement of the alpine haselgebirge mélange, similar to the known lower jurassic blocks from the outer shelf in the berchtesgaden salt mine (gawlick et al., 2009). the block can be attributed to the dürrnberg formation, representing a deeper shelf facies (gawlick et al., 2009), which can only be reconstructed today from various blocks that are incorporated in different mélanges (i.e. haselgebirge mélange, hallstatt mélange). 3. radiolarian biostratigraphy the microfacies of this studied lower jurassic block is that of a slightly bioturbated marly siliceous radiolarian-spicule wacketo packstone with some broken crinoids, similar to the pliensbachian microfacies figured in o’dogherty & gawlick (2008; fig. 4). for radiolarian studies, three samples were processed in acetic acid (8–10 %) for five days. the residue was washed and sieved through a 63 µm mesh. radiolarians were picked and observed under a stereomicroscope and photographed with a leica scanning electron microscope. of all the processed samples, only one (ok-w368), yielded a well-preserved radiolarian assemblage. altogether 53 species belonging to 30 genera were identified (table 1), and are illustrated in pls. 1–4. of these, 14 species are in open nomenclature and six are described with either affinis or confer. we use the generic names revised by o’dogherty et al. (2009). the species level taxonomy is according to goričan et al. (2006) and more recent taxonomic studies (cifer et al., 2020; tekin et al., 2020; cifer & goričan, 2023a, b). for age determination, the global radiolarian zonation by carter et al. (2010) was used. the studied radiolarian assemblage from sample ok-w368 is assigned to the uppermost lower pliensbachian gigi fustis– lantus sixi radiolarian zone (ua 12–18 of carter et al., 2010), based on the first appearance of archaeohagiastrum figure 3. a simplified geological map of the western weitenau region, with the indicated sample locality of the haselgebirge mélange with the lower jurassic radiolarian-bearing block of the dürrnberg formation, after krische et al. (2013a). lammer basin: middle to upper jurassic, indicated with white; hochreith unit and the east and central weitenau: early cretaceous to quaternary, indicated with white. g eo lo gi a c ro at ic a 6 geologia croatica 78/1 longipes baumgartner and the last appearance of napora reiferensis (pessagno, whalen & yeh). other important age diagnostic taxa that support a pliensbachian age for the studied fauna are bagotum maudense pessagno & whalen (stratigraphic range from the lower pliensbachian canutus tipper–katroma clara zone to the lower toarcian napora relica–eucyrtidiellum disparile zone), helvetocapsa cf. plicata plicata (matsuoka) (lower pliensbachian zartus mostleri–pseudoristola megaglobosa zone to lower toarcian napora relica–eucyrtidiellum disparile zone), lantus praeobesus carter (lower pliensbachian canutus tipper–katroma clara zone to upper pliensbachian eucyrtidiellum nagaiae–praeparvicingula tlellensis zone); naropa vi hori, whalen & dumitrica (lower pliensbachian gigi fustits–lantus sixi zone to upper pliensbachian eucyrtidiellum nagaiae–praeparvicingula tlellensis zone); parahsuum mostleri (yeh) (lower pliensbachian zartus mostleri–pseudoristola megaglobosa zone to lower toarcian napora relica–eucyrtidiellum disparile zone) and paronaella variabilis carter (lower pliensbachian gigi-fustis–lantus sixi zone to aalenian higumastra transversa–napora nipponica zone). the ranges of naropa vi and parahsuum mostleri were later extended downwards to the canutus tipper–katroma clara radiolarian zone (cifer et al., 2022). this fauna is similar in age to the well-known and extremely well-preserved radiolarian assemblage from sample 1662d from the gümüʂlü allochthonous unit in turkey (e.g., de wever, 1981a, b, 1982a, b; pessagno & poisson, 1981; goričan et al., 2006) and the radiolarian fauna from sample bmw21 from the teltschengraben in the northern calcareous alps, austria (o’dogherty & gawlick, 2008). several species were identified in the studied sample from weitenau that were previously only identified from sample 1662d (turkey) and bmw21 (teltschengraben). these are paronaella tripla de wever, orbiculiformella radiata de wever and paronaella hirsuta (de wever). two of these species, orbiculiformella radiata de wever and paronaella hirsuta (de wever), were identified exclusively at these three localities, only paronaella tripla de wever was identified at one additional locality, in haida gwaii, british columbia (carter et al., 1988). other age diagnostic species that are common but not exclusive to the studied sample from weitenau and the afore mentioned samples from teltschegraben and turkey, are parahsuum mostleri (yeh), zhamoidellum sutnal (o’dogherty & gawlick), homoeoparonaella lowryensis whalen & carter, archaeohagiastrum longipes baumgartner. figure 4. microfacies of sample ok-w368 is a slightly bioturbated marly siliceous radiolarian-spicule wacketo packstone, belonging to the dürrnberg formation. the scale bar is 200 µm. g eologia c roatica 7cifer et al.: early jurassic radiolarians from the weitenau area (northern calcareous alps, austria) and their implications for palaeogeography 4. palaeogeographic provenance and importance of the lower jurassic outer shelf sedimentary sequence of the weitenau area the wider area around the present position of the analysed exotic block incorporated into the haselgebirge mélange is characterized throughout the whole early to early-middle jurassic by the deposition of red condensed nodular limestones (böhm, 1992; gawlick et al., 1999). in contrast, the provenance area of the studied block is characterized by predominantly grey siliceous limestones and in parts marly limestones and marls that were deposited on either the outer shelf (fig. 2; dürrnberg formation – gawlick et al., 2001), or deep-water basins in the tirolic unit (golebiowski, 1990, 1991), formed in the latest triassic lagoonal areas in the former central shelf position (fig. 2). the colouring is darker and the clay content is significantly higher in rocks of the outer (hallstatt) shelf than in the brighter, spicula-rich siliceous limestones in the central to proximal shelf areas (fig. 2; böhm, 1992; gawlick et al., 2009). in addition, the thickness of the lower jurassic sequence deposited in the outer shelf seems significantly higher in comparison with the age equivalent siliceous limestones in the proximal and central shelf areas of the tirolic unit. this difference can be easily recognized by the sequences preserved in the various known rocks of the dürrnberg and birkenfeld formation, with thicknesses of up to 30 m, deposited in a very short time interval (gawlick et al., 2001, 2009; o´dogherty & gawlick, 2008; missoni & gawlick, 2011b). it can be estimated that the thickness of the dürrnberg formation reaches up to 200 m in some cases. furthermore, the microfacies characteristics of the dürrnberg formation differ significantly from age equivalent grey siliceous limestones deposited in the former central shelf area (gawlick et al., 2009). nevertheless, the clay content in the outer shelf sedimentary sequence decreased during the rhaetian (zlambach formation; krystyn, 2008) to the sinemurian– pliensbachian (dürrnberg formation; gawlick et al., 2001). this decrease in clay content can be easily explained by the ongoing extension in the area of the later alpine atlantic where, during the evolving graben structure from middle to late hettangian times, a clay-rich sedimentary succession was deposited (bündner schists; tollmann, 1977 and references therein). in the toarcian to aalenian birkenfeld formation, the clay content increased again and led to the deposition of siliceous marls on the outer (hallstatt; fig. 2) shelf area. the increasing clay content on the outer shelf is interpreted as the result of the onset of ophiolite obduction (missoni & gawlick, 2011a, b). a similar general sedimentological evolution is known from various blocks in the hallstatt mélange of serbia (gawlick et al., 2017, 2018). lithological differences between the outer shelf sedimentation from the northern calcareous alps and dinarides are the much lower clay content in the grey siliceous and spicula-rich limestones and the limited thickness in the latter, while the microfacies are similar in both. however, a comprehensive biostratigraphic proof, e.g., with ammonoids or radiolarians, has not yet been table 1. identified radiolarian taxa in sample ok-w368. the stratigraphic range is indicated for species with known ranges expressed in unitary associations (ua; after carter et al., 2010).  indicates, which species have their stratigraphic ranges, published in carter et al. (2010), extended based on later studies (cifer et al., 2020, 2022; cifer & goričan, 2023a, b). the studied assemblage is assigned to the gigi fustis – lantus sixi radiolarian zone (ua 12–18). radiolarian taxa ua acaeniotylopsis? sp. archaeocenosphaera ruesti pessagno & yang archaeodictyomitra sp. archaeohagiastrum longipes baumgartner 14–41 bagotum erraticum pessagno & whalen bagotum maudense pessagno & whalen 02–26 beatricea? sp. canoptum anulatum pessagno & poisson 06–28 canoptum columbiaense whalen & carter 01–20 charlottea sp. crucella jadeae carter & dumitrica crucella squama (kozlova) crucella sp. doliocapsa sp. 1 sensu cifer et al. (2020) doliocapsa sp. c sensu cifer & goričan (2023a) droltus hecatensis pessagno & whalen dumitricaella aff. trispinosa dumitrica farcus cf. asperoensis pessagno, whalen & yeh farcus kozuri yeh hagiastrum macrum gr. de wever hagiastrum sp. helvetocapsa cf. plicata plicata (matsuoka) 08–27 homoeoparonaella lowryensis whalen & carter 03–20 katroma sp. lantus praeobesus carter 02–20 loupanus pliensbachicus cifer loupanus cf. sp. a sensu cifer & goričan (2023b) loupanus sp. c sensu cifer & goričan (2023b) mendacastrum? sp. a sensu cifer & goričan (2023b) napora reiferensis (pessagno, whalen & yeh) 09–17 naropa vi hori, whalen & dumitrica 12–19 orbiculiformella radiata de wever orbiculiformella sp. pantanellium carlense whalen & carter pantanellium inornatum pessagno & poisson 03–22 parahsuum mostleri (yeh) 06–27 parahsuum simplum yao 01–36 paronaella aff. bona (yeh) paronaella grahamensis carter 03–34 paronaella hirsuta (de wever) paronaella notabilis whalen & carter paronaella snowshoensis (yeh) paronaella tripla de wever paronaella variabilis carter 17–34 paronaella sp. a sensu cifer & goričan (2023b) praeconocaryomma bajaensis whalen 06–38 praeconocaryomma pravimamma pessagno & poisson praeconocaryomma whiteavesi carter 08–23 tozerium filzmoosense cifer tripocyclia? tortuosa dumitrica, goričan & whalen zhamoidellum sutnal (o’dogherty & gawlick) zhamoidellum yehae dumitrica zhamoidellum sp. g eo lo gi a c ro at ic a 8 geologia croatica 78/1 achieved, due to the lack of ammonoids and the generally predominant recrystallization of radiolarians. the age can only be estimated by the underlying conodont bearing latest triassic limestones and the overlying middle jurassic radiolarites. in the inner western carpathians similar successions are not known. although the deposition of open-marine sedimentary rocks in the outer shelf region of the western to north-western passive continental margin of the neo-tethys continued without a break from late triassic to early middle jurassic times, the detailed evolution is only poorly known due to the destruction of the whole outer shelf area during the middle– late jurassic ophiolite obduction (gawlick et al., 2008; schmid et al., 2008; gawlick & missoni, 2019), with the formation of various ophiolitic and sedimentary mélanges throughout the whole of the western tethyan realm. the analysis of the exotic block in the haselgebirge mélange of the weitenau area fills therefore an important gap in the knowledge of the evolution of the outer (hallstatt) shelf. the radiolarian bearing block is a missing part of the lower jurassic outer shelf sedimentary sequence and fits perfectly with the known blocks in the hallstatt mélange in the area of hallein-bad dürrnberg (gawlick et al., 2001) or the haselgebirge mélange in the berchtesgaden salt mine (missoni & gawlick, 2011b). furthermore, the existence of this block in the haselgebirge mélange shows the allochthony of the alpine haselgebirge as a far-travelled mélange complex. 5. conclusions the studied fauna is assigned to the lower pliensbachian gigi fustis–lantus sixi radiolarian zone (ua 12–18) of carter et al. (2010). altogether, the fauna comprises 53 species belonging to 30 genera. in terms of age and composition the studied assemblage is closest to the faunas from sample bmw21 (teltschengraben, austria) and sample 1662d (the gümüʂlü allochthonous unit, turkey) as it contains several taxa that were previously only found in these two samples. the well-preserved early jurassic radiolarian assemblage fills an important gap in the knowledge about the early jurassic depositional history of the outer shelf of the neo-tethys passive continental margin. the facies and age of the block, together with the rich and well-preserved radiolarian fauna, contrast significantly from the lower jurassic sedimentary sequence known from the wider area between the tennengebirge mts. to the south and the osterhorn unit to the north. they prove the allochthonous nature of this block, transported in the haselgebirge mélange to its present-day position. the position of the block also indicates a polyphase transport of the haselgebirge mélange during jurassic times from the outer shelf to the central shelf area; that is the former lagoon of the upper triassic hauptdolomite-dachstein carbonate platform. acknowledgment financial support for this work was provided by the slovenian research agency, research core funding no. p1-0008 and young researcher grant program (no. 39186), by the ceepus grant ciii-ro-0038, and in the frame of the igcp-710 projects “western tethys meets eastern tethys”. the samples were processed in the frame of the uzag-programme of the montanuniversität leoben, austria. we thank dr. špela goričan (ivan rakovec institute of palaeontology, research centre of the slovenian academy of sciences and arts) for valuable advice and comments on the manuscript. we also thank nevenka djerić, an anonymous reviewer and the handling editor duje kukoč for important comments and remarks on our study. refferences auer, m., gawlick, h.-j., suzuki, h. & schlagintweit, f. (2009): spatial and temporal development of the siliceous basin and shallow-water carbonate sedimentation in oxfordian northern calcareous alps.– facies, 55, 63–87. https://doi.org/10.1007/s10347-008-0155-3 bertinelli, a. & marcucci, m. (2011): middle and late hettangian radiolarians from mt. camicia succession (gran sasso, central apennines – italy).– riv. ital. paleontol. s., 117, 399–421. https://doi.org/10.13130/ 2039-4942/5983 böhm, f. (1992): mikrofazies und ablagerungsmilieu des lias und dogger der nordöstlichen kalkalpen.– erlanger geologische abhandlungen, 121, 55–217. bragin, n., ledneva, g., bragina, l., tsiolakis, e., symeou, v. & papadimitriou, n. (2022): the radiolarian age and petrographic composition of a block of the lower jurassic volcaniclastic breccia and chert of the mamonia complex, sw cyprus.– geol. croat., 75/1, 115–128. https://doi.org/10.4154/gc.2022.07 bujtor, l., krische, o. & gawlick, h.-j. (2013): late berriasian ammonite assemblage and biostratigraphy of the leube quarry near salzburg (northern calcareous alps, austria).– n. jb. geol. pal. abh., 267, 273– 295. http://doi.org/10.1127/0077-7749/2013/0309 carter, e.s., cameron, b.e.b. & smith, p.l. (1988): lower and middle jurassic radiolarian biostratigraphy and systematic paleontology, queen charlotte islands, british columbia.– geol. surv. can., bull., 386, 1–109. carter, e.s., goričan, š., guex, j., o´dogherty, l., de wever, p., dumitrica, p., hori, r.s., matsuoka, a. & whalen, p.a. (2010): global radiolarian zonation for the pliensbachian, toarcian and aalenian.– palaeogeogr. palaeocl. palaeoec., 297, 401–419. https://doi. org/10.1016/j.palaeo.2010.08.024 chiari, m., baumgartner, p.o., bernoulli, d., bortolli, v., marcucci, m., photiades, a. & principi, g. (2013): late triassic, early and middle jurassic radiolaria from ferromanganese-chert ‘nodules’ (angelokastron, argolis, greece): evidence for prolonged radiolarite sedimentation in the maliac-vardar ocean.– facies, 59, 391–424. https://doi.org/10.1007/s10347-012-0314-4 cifer, t. & goričan, š. (2023a): late sinemurian and early pliensbachian radiolaria from mount rettenstein (northern calcareous alps, austria). part 1. nassellaria.– rev. micropaleontol., 79, 100717. https://doi. org/10.1016/j.revmic.2023.100717 cifer, t. & goričan, š. (2023b): late sinemurian and early pliensbachian radiolaria from mount rettenstein (northern calcareous alps, austria). part 2. entactinaria and spumellaria.– rev. micropaleontol., 81, 100752. https://doi.org/10.1016/j.revmic.2023.100752 cifer, t., goričan, š., gawlick, h.-j. & auer, m. (2020): pliensbachian, early jurassic radiolarians from mount rettenstein in the nort hern calcareous alps, austria.– acta palaeontol. pol., 65/1, 167–207. https:// doi.org/10.4202/app.00618.2019 cifer, t., goričan, š., auer, m., demény, a., fraguas, á., gawlick, h.-j. & riechelmann, s. (2022): integrated stratigraphy (radiolarians, calcareous nannofossils, carbon and strontium isotopes) of the sinemurian–pliensbachian transition at mt. rettenstein, northern calcareous alps, austria.– global planet. change, 212, 103811. https://doi. org/10.1016/j.gloplacha.2022.103811 de wever, p. (1981a): hagiastridae, patulibracchiidae et spongodiscidae (radiolaires polycystines) du lias de turquie.– rev. micropaleontol., 24, 27–50. https://doi.org/10.1007/s10347-008-0155-3 https://doi.org/10.13130/2039-4942/5983 https://doi.org/10.13130/2039-4942/5983 https://doi.org/10.4154/gc.2022.07 http://doi.org/10.1127/0077-7749/2013/0309 https://doi.org/10.1016/j.palaeo.2010.08.024 https://doi.org/10.1016/j.palaeo.2010.08.024 https://doi.org/10.1007/s10347-012-0314-4 https://doi.org/10.1016/j.revmic.2023.100717 https://doi.org/10.1016/j.revmic.2023.100717 https://doi.org/10.1016/j.revmic.2023.100752 https://doi.org/10.4202/app.00618.2019 https://doi.org/10.4202/app.00618.2019 https://doi.org/10.1016/j.gloplacha.2022.103811 https://doi.org/10.1016/j.gloplacha.2022.103811 g eologia c roatica 9cifer et al.: early jurassic radiolarians from the weitenau area (northern calcareous alps, austria) and their implications for palaeogeography de wever, p. (1981b): parasaturnalidae, pantanellidae et sponguridae (radiolaires polycystynes) du lias de turquie.– rev. micropaleontol., 24, 138– 156. de wever, p. (1982a): nassellaria (radiolaires polycystines) du lias de turquie.– rev. micropaleontol., 24, 189–232. de wever, p. (1982b): radiolaires du trias et du lias de la tethys (systématique, stratigraphie).– société géologique du nord, publication, 7, 1–599. faupl, p. & wagreich, m. (2000): late jurassic to eocene palaeogeography and geodynamic evolution of the eastern alps.– mitt. osterr. geol. g., 92, 79–194. festa, a., pini, g.a., dilek, y., ogata, k. & alonso, j.l. (2016): origin and significance of olistostromes in the evolution of orogenic belts: a global synthesis. gondwana res., 39, 180–203. https://doi.org/10.1016/j. gr.2016.08.002 frisch, w. & gawlick, h.-j. (2003): the nappe structure of the central northern calcareous alps and its disintegration during miocene tectonic extrusion – a contribution to understanding the orogenic evolution of the eastern alps.– int. j. earth. sci., 92, 712–727. https://doi.org/10.1007/ s00531-003-0357-4 gawlick, h.-j. & missoni, s. (2013): field trip b2: triassic to early cretaceous geodynamic history of the central northern calcareous alps (northwestern tethyan realm).– berichte der geologischen bundesanstalt, 99, 216–270, wien. gawlick, h.-j. & missoni, s. (2019): middle-late jurassic sedimentary mélange formation related to ophiolite obduction in the alpine-carpathian-dinaridic mountain range.– gondwana res., 74, 144–172. http://doi. org/10.1016/j.gr.2019.03.003 gawlick, h.-j. & schlagintweit, f. (2006): berriasian drowning of the plassen carbonate platform at the type-locality and its bearing on the early eoalpine orogenic dynamics in the northern calcareous alps (austria).– int. j. earth. sci., 95, 451–462. http://doi.org/10.1007/s00531-0050048-4 gawlick, h.-j., frisch, w., vecsei, a., steiger, t. & böhm, f. (1999): the change from rifting to thrusting in the northern calcareous alps as recorded in jurassic sediments.– geol. rdschau., 87, 644–657. gawlick, h.-j., suzuki, h. & missoni, s. (2001): nachweis von unterliassischen beckensedimenten in hallstätter fazies (dürrnberg-formation) im bereich der hallein – berchtesgadener hallstätter zone und des lammer beckens (hettangium – sinemurium).– mitteilungen der gesellschaft der geologieund bergbaustudenten in österreich, 45, 39–55. gawlick, h.-j., schlagintweit, f. & suzuki, h. (2007): the late jurassic to early cretaceous sedimentary succession of the höhersteinsandling area (salzkammergut, austria) – implications for the reconstruction of the block puzzle in the central northern calcareous alps, the structure and evolution of the radiolaritic flysch basins and of the plassen carbonate platform.– neues jahrb. geol. p.-a., 243/1, 1–70. http://doi. org/10.1127/0077-7749/2007/0243-0001 gawlick, h.-j., frisch, w., hoxha, l., dumitrica, p., krystyn, l., lein, r., missoni, s. & schlagintweit, f. (2008): mirdita zone ophiolites and associated sediments in albania reveal neotethys ocean origin.– int. j. earth sci., 97, 865–881. http://doi.org/10.1007/ s00531-007-0193-z gawlick, h.-j., missoni, s., schlagintweit, f., suzuki, h., frisch, w., krystyn, l., blau, j. & lein, r. (2009): jurassic tectonostratigraphy of the austroalpine domain.– journal of alpine geology, 50, 1–152. gawlick, h.-j., missoni, s., schlagintweit, f. & suzuki, h. (2012): jurassic active continental margin deep-water basin and carbonate platform formation in the north-western tethyan realm (austria, germany).– journal of alpine geology, 54, 189–292. gawlick, h.-j., missoni, s., sudar, m.n., gorican, s., lein, r., stanzel, a.i. & jovanovic, d. (2017): open-marine hallstatt limestones reworked in the jurassic zlatar mélange (sw serbia): a contribution to understanding the orogenic evolution of the inner dinarides.– facies, 63, 29. http://doi.org/10.1007/s10347-017-0507-y gawlick, h.-j., missoni, s., sudar, m.n., suzuki, h., meres, s., lein, r. & jovanovic, d. (2018): the jurassic hallstatt mélange of the inner dinarides (sw serbia): implications for triassic-jurassic geodynamic and palaeogeographic reconstructions of the western tethyan realm.– neues jahrb. geol. p.-a., 288/1, 1–47. http://doi.org/10.1127/njgpa/2018/0721 golebiowski, r. (1990): the alpine kössen formation, a key for european topmost triassic correlations. a sequenceand ecostratigraphic contribution to the norian-rhaetian discussion.– albertiana, 8, 25–35. golebiowski, r. (1991): becken und riffe der alpinen obertrias – lithostratigraphie und biofazies der kössener formation.– in: nagel, d. & rabeder, g. (eds.): exkursionen im jungpaläozoikum und mesozoikums österreichs. österreichische paläontologische gesellschaft, wien, 79–119. goričan, š., šmuc, a. & baumgartner, p.o. (2003): toarcian radiolaria from mt. mangart (slovenian-italian border) and their paleoecological implications.– mar. micropaleontol., 49, 275–301. http://doi. org/10.1016/s0377-8398(03)00034-3 goričan, š., carter, e.s., dumitrica, p., whalen, p.a., hori, r.s., de wever, p., o’dogherty, l., matsuoka, a. & guex, j. (2006): catalogue and systematics of pliensbachian, toarcian and aalenian radiolarian genera and species.– zrc publishing, scientific research centre of the slovenian academy of sciences and arts, ljubljana, 446 pp. goričan, š., carter, e.s., guex, j., o’dogherty, l., de wever, p., dumitrica, p., hori, r.s., matsuoka, a. & whalen, p.a. (2013): evolutionary patterns and paleobiogeography of pliensbachian and toarcian (early jurassic) radiolaria.– palaeogeogr. palaeocl. palaeoec., 386, 620–636. http://doi.org/10.1016/j.palaeo.2013.06.028 guex, j., bartolini, a., atudorel, v. & taylor, d. (2004): high resolution ammonite and carbon isotope stratigraphy across the triassic– jurassic boundary at new york canyon (nevada).– earth planet. sc. lett., 225, 29–41. http://doi.org/10.1016/j.epsl.2004.06.006 handy, m.r., schmid, s.m., bousquet, r., kissling, e. & bernoulli, d. (2010): reconciling plate-tectonic reconstructions of alpine tethys with the geological-geophysical record of spreading and subduction in the alps.– earth-sci. rev., 102, 121–158. http://doi.org/10.1016/ j.earscirev.2010.06.002 hillebrandt, a.v. & krystyn, l. (2009): on the oldest jurassic ammonites of europe (northern calcareous alps, austria) and their global significance.– neues jahrb. geol. p.-a., 253, 163–195. http://doi.org/ 10.1127/0077-7749/2009/0253-0163 hubbard, r.n.b.l. & boutler, m.c. (2000): phytogeography and palaeoecology in western europe and eastern greenland near the triassic– jurassic boundary.– palaios, 15, 120–131. janák, m., froitzheim, n., lupták, b., vrabec, m. & krogh ravna, e.j. (2004): first evidence for ultrahigh-pressure metamorphism of eclogites in pohorje, slovenia: tracing deep continental subduction in the eastern alps.– tectonics, 23/5, tc5014. http://doi.org/ 10.1029/2004tc001641 kirchner, e.ch. (1980): natriumabphibole und natriumpyroxene als mineralneubildungen in sedimenten und basichen vulkaniten aus dem permoskyth der nörlichen kalkalpen.– verhandlungen der geologischen bundesanstalt, 1980/3, 249–279. kozur, h. & mostler, h. (1990): saturnaliacea deflandre and some other stratigraphically important radiolaria from the hettangian of lenggries/ isar (bavaria, northern calcareous alps).– geologisch paläontologische mitteilungen innsbruck, 17, 179–248. krische, o. & gawlick, h.-j. (2015): age and significance of lower cretaceous mass flows: ischler breccia revisited (rossfeld formation, northern calcareous alps, austria).– austrian j. earth sc., 108, 128–150. http:// doi.org/10.17738/ajes.2015.0017 krische, o., suzuki, h. & gawlick h.-j. (2013a): mikrofazies und radiolarienfauna der saccocoma-kalke in der westlichen weitenau (hochreith einheit) [nördliche kalkalpen, salzburg]: neue daten zur platznahme der alpinen haselgebirge mélange.– jahrbuch der geologischen bundesanstalt, 153/1–4, 75–96. krische, o., bujtor, l. & gawlick h.-j. (2013b): calpionellid and ammonite biostratigraphy of uppermost jurassic to lower cretaceous sedihttps://doi.org/10.1016/j.gr.2016.08.002 https://doi.org/10.1016/j.gr.2016.08.002 https://doi.org/10.1007/s00531-003-0357-4 https://doi.org/10.1007/s00531-003-0357-4 http://doi.org/10.1016/j.gr.2019.03.003 http://doi.org/10.1016/j.gr.2019.03.003 http://doi.org/10.1007/s00531-005-0048-4 http://doi.org/10.1007/s00531-005-0048-4 http://doi.org/10.1127/0077-7749/2007/0243-0001 http://doi.org/10.1127/0077-7749/2007/0243-0001 http://doi.org/10.1007/s00531-007-0193-z http://doi.org/10.1007/s00531-007-0193-z http://doi.org/10.1007/s10347-017-0507-y http://doi.org/10.1127/njgpa/2018/0721 http://doi.org/10.1127/njgpa/2018/0721 http://doi.org/10.1016/s0377-8398(03)00034-3 http://doi.org/10.1016/s0377-8398(03)00034-3 http://doi.org/10.1016/j.palaeo.2013.06.028 http://doi.org/10.1016/j.epsl.2004.06.006 http://doi.org/10.1016/j.earscirev.2010.06.002 http://doi.org/10.1016/j.earscirev.2010.06.002 http://doi.org/10.1127/0077-7749/2009/0253-0163 http://doi.org/10.1127/0077-7749/2009/0253-0163 http://doi.org/10.1029/2004tc001641 http://doi.org/10.1029/2004tc001641 http://doi.org/10.17738/ajes.2015.0017 http://doi.org/10.17738/ajes.2015.0017 g eo lo gi a c ro at ic a 10 geologia croatica 78/1 mentary rocks from the leube quarry (northern calcareous alps, salzburg, austria).– austrian j. earth sc., 106/1, 26–45. krische, o., goričan, š. & gawlick, h.-j. (2014): erosion of a jurassic ophiolitic nappe-stack as indicated by exotic components in the lower cretaceous rossfeld formation of the central northern calcareous alps (austria).– geol. carpath., 65, 3–24. http://doi.org/10.2478/geoca-2014-0001 krische, o., grabowski, j., bujtor, l. & gawlick, h.-j. (2018): latest jurassic to early cretaceous evolution in the central northern calcarous alps.– berichte der geologischen bundesanstalt, 126, 223–258. krystyn, l. (2008): the hallstatt pelagics – norian and rhaetian fossillagerstaetten of hallstatt.– berichte der geologischen bundesanstalt, wien, 86, 81–98. lein, r. (1987): evolution of the northern calcareous alps during triassic times.– in: flügel, h.w. & faupl, p. (eds.): geodynamics of the eastern alps. deuticke, wien, 85–102. linzer, h.-g., ratschbacher, l. & frisch, w. (1995): transpressional collision structures in the upper crust: the fold-thrust belt of the northern calcareous alps.– tectonophysics, 242/1–2, 41–61. http://doi. org/10.1016/0040-1951(94)00152-y missoni, s. & gawlick, h.-j. (2011a): evidence for jurassic subduction from the northern calcareous alps (berchtesgaden; austroalpine, germany).– int. j. earth sci., 100, 1605–1631. http://doi.org/10.1007/s00531010-0552-z missoni, s. & gawlick, h.-j. (2011b): jurassic mountain building and mesozoic-cenozoic geodynamic evolution of the northern calcareous alps as proven in the berchtesgaden alps (germany).– facies, 57/1, 137–186. http://doi.org/10.1007/s10347-010-0225-1 missoni, s., schlagintweit, f., suzuki, h. & gawlick, h.-j. (2001): die oberjurassische karbonatplattformentwicklung im bereich der berchtesgadener kalkalpen (deutschland) – eine rekonstruktion auf der basis von untersuchungen polymikter brekzienkörper in pelagischen kieselsedimenten (sillenkopf-formation).– zbl. geol. paläont., 2000/1/2, 117–143. neubauer, f., friedl, g., genser, j., handler, r., mader, d. & schneider, d. (2007): origin and tectonic evolution of eastern alps deduced from dating of detrital white mica: a review.– austrian j. earth sc., 100, 8–23. o’dogherty, l. & gawlick, h.-j. (2008): pliensbachian radiolarians in teltschengraben (northern calcareous alps, austria): a keystone in reconstructing the early jurassic evolution of the tethys.– stratigraphy, 5, 63–81. http://doi.org/10.29041/strat.05.1.05 o'dogherty, l., goričan, š. & de wever, p. (2009): catalogue of mesozoic radiolarian genera: part 2, jurassic-cretaceous.– geodiversitas, 31, 271–356. http://doi.org/10.5252/g2009n2a4 pálfy, j. (2008): triassic-jurassic boundary.– in: mccann, t. (ed.): the geology of central europe. volume 2: mesozoic and cenozoic, geological society, london, 826–827. pessagno, e.a. jr. & poisson, a. (1981): lower jurassic radiolaria from the gümüslü allochton of southwestern turkey (taurides occidentales).– bulletin of the mineral research and exploration institute of turkey, 92, 47–69. plöchinger, b. (1974): gravitativ transportiertes permisches haselgebirge in den oberalmer schichten (tithonium, salzburg).– verhandlungen der geologischen bundesanstalt, 1974/1, 71–88. plöchinger, b. (1976): die oberalmer schichten und die platznahme der hallstätter masse in der zone hallein-berchtesgaden.– neues jahrb. geol. p.-a., 151/3, 304–324. plöchinger, b. (1979): argumente für die intramalmische eingleitung von hallstätter schollen bei golling (salzburg).– verhandlungen der geologischen bundesanstalt, 1979/2, 181–194. plöchinger, b. (1987): geologische karte der republik österreich 1:50.000, blatt 94 hallein.– geologische bundesanstalt wien. plöchinger, b. (1990): geologische karte der republik österreich 1:50.000, erläuterungen zu blatt 94 hallein.– geologische bundesanstalt wien, 1–76. pueyo, e.l., mauritsch, h.j., gawlick, h.-j., scholger, r. & frisch, w. (2007): new evidence for block and thrust sheet rotations in the central northern calcareous alps deduced from two pervasive remagnetization events.– tectonics, 26/5, tc5011. http://doi.org/10.1029/ 2006tc001965 ratschbacher, l., frisch, w., linzer, h.-g. & olivier, m. (1991): lateral extrusion in the eastern alps, part 2: structural analysis.– tectonics, 10/2, 257–1991. http://doi.org/10.1029/90tc02623 schlagintweit, f., gawlick, h.-j., ebli, o., rünstler, h. & suzuki, h. (2003): die plassen-formation (kimmeridgium) des krahstein (steirisches salzkammergut, österreich) und deren unterlagerung: neue daten zur fazies, biostratigraphie und sedimentologie.– gmundner geo -studien, 2, 87–96. schmid, s.m., fügenschuh, b., kissling, e. & schuster, r. (2004): tectonic map and overall architecture of the alpine orogen.– eclogae geol. helv., 97, 93–117. http://doi.org/10.1007/s00015-004-1113-x schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine-carpathian-dinaride-orogenic system: correlation and evolution of tectonic units.– swiss j. geosci., 101, 139–183. schorn, a. & neubauer, f. (2011): emplacement of an evaporitic mélange nappe in central northern calcareous alps: evidence from the moosegg klippe (austria).– austrian j. earth sc., 104/2, 22–46. schorn, a., neubauer, f., genser, j. & bernroider, m. (2013): the haselgebirge evaporitic mélange in central northern calcareous alps (austria): part of the permian to lower triassic rift of the meliata ocean?– tectonophysics, 583, 28–48. http://doi.org/10.1016/j.tecto.2012. 10.016 sepkoski, j.j., jr. (1996): patterns of phanerozoic extinction: a perspective from global databases.– in: walliser, o.h. (ed.): global events and event stratigraphy in the phanerozoic, 35–51. springer, berlin heidelberg. spötl, ch., longstaffe, f.j., ramseyer, k., kunks, m.j. & wiesheu, r. (1998): fluid-rock reactions in an evaporitic mélange, permian haselgebirge, austrian alps.– sedimentology, 45, 1019–1044. http:// doi.org/10.1046/j.1365-3091.1998.00188.x steiger, t. & wurm, d. (1980): faziesmuster oberjurassischer plattformkarbonate (plassen-kalke, nördliche kalkaplen, steirisches salzkammergut, österreich).– facies, 2, 241–284. tekin, u.k. (2002): lower jurassic (hettangian–sinemurian) radiolarians from the antalya nappes, central taurids, southern turkey.– micropaleontology, 48, 177–205. http://doi.org/10.1661/0026-2803(2002)048[0177: ljhsrf]2.0.co;2 tekin, u.k., krystyn, l., okuyucu, c., bedi, y. & sayit, k. (2020): late triassic to early jurassic radiolarian, conodont and ammonite assemblages from the tavuscayiri block, mersin mélange, southern turkey: time constraints for the t/j boundary and sedimentary evolution of the southern margin of the northern neotethys.– geodiversitas, 42/27, 493– 537. http://doi.org/10.5252/geodiversitas2020v42a27 tollmann, a. (1977): geologie von österreich, band 1. deuticke, 766 pp, wien. tollmann, a. (1985): geologie von österreich, band 2: außerzentralalpiner anteil. deuticke, 1–710, wien. von eynatten, h. & gaupp, r. (1999): provenance of cretaceous synorogenic sandstones in the eastern alps: constraints from framework petrography, heavy mineral analysis and mineral chemistry.– sediment. geol., 124/1–4, 81–111. http://doi.org/10.1016/s0037-0738(98)00122-5 von eynatten, h., gaupp, r. & wijbrans, j.r. (1996): 40ar/39ar laser-probe dating of detrital white micas from cretaceous sedimentary rocks of the eastern alps: evidence for variscan high-pressure metamorphism and implications for alpine orogeny.– geology, 24/8, 691–694. http:// doi.org/10.1130/0091-7613(1996)024<0691:aalpdo>2.3.co;2 http://doi.org/10.2478/geoca-2014-0001 http://doi.org/10.2478/geoca-2014-0001 http://doi.org/10.1016/0040-1951(94)00152-y http://doi.org/10.1016/0040-1951(94)00152-y http://doi.org/10.1007/s00531-010-0552-z http://doi.org/10.1007/s00531-010-0552-z http://doi.org/10.1007/s10347-010-0225-1 http://doi.org/10.29041/strat.05.1.05 http://doi.org/10.5252/g2009n2a4 http://doi.org/10.1029/2006tc001965 http://doi.org/10.1029/2006tc001965 http://doi.org/10.1029/90tc02623 http://doi.org/10.1007/s00015-004-1113-x http://doi.org/10.1016/j.tecto.2012.10.016 http://doi.org/10.1016/j.tecto.2012.10.016 http://doi.org/10.1046/j.1365-3091.1998.00188.x http://doi.org/10.1046/j.1365-3091.1998.00188.x http://doi.org/10.1661/0026-2803(2002)048%5b0177:ljhsrf%5d2.0.co;2 http://doi.org/10.1661/0026-2803(2002)048%5b0177:ljhsrf%5d2.0.co;2 http://doi.org/10.5252/geodiversitas2020v42a27 http://doi.org/10.1016/s0037-0738(98)00122-5 http://doi.org/10.1130/0091-7613(1996)024%3c0691:aalpdo%3e2.3.co;2 http://doi.org/10.1130/0091-7613(1996)024%3c0691:aalpdo%3e2.3.co;2 g eologia c roatica 11cifer et al.: early jurassic radiolarians from the weitenau area (northern calcareous alps, austria) and their implications for palaeogeography plate 1. sample ok-w368. scale bar is 100 µm. a – 4, 21, 22; b – 1, 3, 7, 11, 13–16, 18–20; c – 2, 5, 6, 8–10, 12, 17. 1 – hagiastrum sp., ok-w368-1.001; 2 – archaeohagiastrum longipes baumgartner, ok-w368-1.002; 3 – hagiastrum macrum gr. de wever, ok-w368-1.003; 4 – crucella squama (kozlova), ok-w368-2.010; 5 – crucella jadeae carter & dumitrica, ok-w368-1.014; 6 – homoeoparonaella lowryensis whalen & carter, ok-w368-1.013; 7 – paronaella variabilis carter, ok-w368-1.015; 8, 10, 15 – paronaella sp. a sensu cifer & goričan (2023b), ok-w368-1.016, ok-w368-1.019, ok-w368-2.009; 9 – paronaella aff. bona (yeh), ok-w368-1.017; 11 – paronaella notabilis whalen & carter, ok-w368-1.006; 12 – paronaella tripla de wever, ok-w368-1.008; 13, 14, 18 – paronaella grahamensis carter, ok-w368-2.002, ok-w368-2.008, ok-w368-2.103; 16 – paronaella hirsuta (de wever), ok-w368-1.004; 17 – paronaella snowshoensis (yeh), ok-w368-2.101; 19 – orbiculliformella sp., ok-w368-2.032; 20 – orbiculiformella radiata de wever, ok-w368-1.007; 21 – crucella sp., ok-w368-2.104; 22 – mendacastrum? sp. a sensu cifer & goričan (2023b), ok-w368-2.017. g eo lo gi a c ro at ic a 12 geologia croatica 78/1 plate 2. sample ok-w368. scale bar is 100 µm. a – 17, 18; b – 1–16, 19–29. 1-6 – pantanellium inornatum pessagno & poisson, ok-w368-1.073, ok-w368-1.079, ok-w368-1.088, ok-w368-1.109, ok-w368-1.119, ok-w368-2.014; 7 – pantanellium carlense whalen & carter, ok-w368-2.026; 8, 9 – acaeniotylopsis? sp., ok-w368-1.098, ok-w368-1.123; 10 – loupanus pliensbachicus cifer, ok-w368-1.084; 11 – loupanus sp. c sensu cifer & goričan (2023b), ok-w368-2.018; 12, 15, 16 – beatricea? sp., ok-w368-1.112, ok-w368-2.023, ok-w368-2.080; 13, 14 – loupanus cf. sp. a sensu cifer & goričan (2023b), ok-w368-1.128, ok-w368-2.015; 17 – tozerium filzmoosense cifer, ok-w368-2.086; 18 – tripocyclia? tortuosa dumitrica, goričan & whalen, ok-w368-2.089; 19 – charlottea sp., ok-w368-2.097; 20-22 – archaeocenosphaera ruesti pessagno & yang, ok-w368-1.053, ok-w368-1.103, ok-w368-1.115; 23, 24, 27, 29 – praeconocaryomma whiteavesi carter, ok-w368-1.062, ok-w368-1.063, ok-w368-1.111, ok-w368-2.061; 25, 28 – praeconocaryomma bajaensis whalen, ok-w368-1.064, ok-w368-2.049; 26 – praeconocaryomma parvimamma pessagno & poisson, ok-w368-1.101. g eologia c roatica 13cifer et al.: early jurassic radiolarians from the weitenau area (northern calcareous alps, austria) and their implications for palaeogeography plate 3. sample ok-w368. scale bar is 100 µm. 1-5, 8 – parahsuum simplum yao, ok-w368-1.023, ok-w368-1.038, ok-w368-2.035, ok-w368-1.114, ok-w368-2.037, ok-w368-1.028; 6, 7 – parahsuum mostleri (yeh), ok-w368-2.044, ok-w368-1.124; 9-12 – droltus hecatensis pessagno & whalen, ok-w368-1.039, ok-w368-1.045, ok-w368-1.125, ok-w368-2.033; 13 – archaeodictyomitra sp., ok-w368-1.107; 14 – canoptum anulatum pessagno & poisson, ok-w368-1.026; 15-17 – canoptum columbiaense whalen & carter, ok-w368-1.029, ok-w368-1.030, ok-w368-2.036; 18-20 – lantus praeobesus carter, ok-w368-1.033, ok-w368-1.035, ok-w368-1.099; 21-23 – bagotum erraticum pessagno & whalen, ok-w368-1.126, ok-w368-2.069, ok-w368-2.075; 24-26 – bagotum maudense pessagno & whalen, ok-w368-2.070, ok-w368-1.024, ok-w368-2.081. g eo lo gi a c ro at ic a 14 geologia croatica 78/1 plate 4. sample ok-w368. scale bar is 100 µm. a – 1, 3, 5–16; b – 4; c – 2. 1 – zhamoidellum sp., ok-w368-1.066; 2, 3 – zhamoidellum yehae dumitrica, ok-w368-1.052, ok-w368-1.085; 4 – zhamoidellum sutnal (o'dogherty & gawlick), ok-w368-1.068; 5 – helvetocapsa cf. plicata plicata (matsuoka), ok-w368-2.068; 6, 7 – katroma sp., ok-w368-1.108, ok-w368-2.038; 8 – doliocapsa sp. 1 sensu cifer et al. (2020), ok-w368-2.055; 9 – doliocapsa sp. c sensu cifer & goričan (2023a), ok-w368-1.040; 10, 11 – farcus kozuri yeh, ok-w368-1.076, ok-w368-1.070; 12 – naropa vi hori, whalen & dumitrica, ok-w368-2.028; 13 – farcus cf. asperoensis pessagno, whalen & yeh, ok-w368-1.087; 14 – dumitricaella aff. trispinosa dumitrica, ok-w368-2.030. this specimen has bigger v and l spines than the type material. these spines are equal in size to the apical horn; 15 – napora reiferensis (pessagno, whalen & yeh), ok-w368-2.108. 2018 | 71/2 | 55–64 | 11 figs. | 3 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction natural disasters such as flash flooding, earthquakes, groundwater contamination and climate change have had an influence on national development activity, which has led to a negative impact on human health and the geo-environment. groundwater contamination is one of the most challenging geo-environmental issues encountered in many countries, resulting in rendering the quality of groundwater unsafe for consumption and agriculture (yousef et al., 2015). more complicated problems arise when the surface, or subsurface, has experienced an earthquake vibration, which then influences the migration of apl and napl into groundwater sources. vibration leads to the rearrangement of the soil structure resulting in the development of an unstable soil structure, cracked soil, and volumetric deformation of soil aggregate structures, all of which can create problems that affect the characteristic pore sizes of the soils (loke et al., 2017). these problems need to be overcome to ensure the sustainability of groundwater resources and the geo-environment. multiple porosity soil models have been widely used to characterize soil with different pore sizes and hydraulic properties (ngien et al., 2011). however, this requires further investigation especially with respect to a fractured soil condition and contaminant transport. the danger of releasing toxic chemicals means that on-site real-time studies are not feasible and have been replaced by physical experimental simulations and modelling. the most serious contaminants include petroleum hydrocarbons such as toluene, which can be classified as a type of liquid with a den study of aqueous and non-aqueous phase liquid in fractured double-porosity soil using digital image processing loke kok foong1, norhan abd rahman2 , ramli nazir2 and roland w lewis3 1 universiti teknologi malaysia, faculty of civil engineering, johor, malaysia; (edwinloke84@yahoo.com) 2 universiti teknologi malaysia, centre of tropical geoengineering, faculty of civil engineering, johor, malaysia 3 university of wales swansea, school of engineering, swansea, w. glam, sa2 8pp, united kingdom doi: 10.4154/gc.2018.12 abstract the leakage and spillage of non-aqueous phase liquids (napls) and aqueous phase liquids (apls) contribute to groundwater contamination, resulting in groundwater pollution and rendering the quality of groundwater unsafe for drinking and agriculture. ensuring the availability and sustainable management of water and sanitation for all was the goal and target of the 2030 united nations agenda for sustainable development, consisting of a plan of action for the population, the planet and general prosperity. this paper is intended to investigate the aqueous and nonaqueous phase liquid migrations in a deformable double-porosity soil, which has become important for both sustainable groundwater use and the comprehensive understanding of the behaviour of liquid migration into groundwater. a modelling experiment was conducted in an attempt to study the pattern and behaviour of aqueous and non-aqueous phase liquid migration in fractured double-porosity soil using a digital image processing technique. the results of the experiments show that the flow of the apl and napl migration was not uniformly downward. faster migration occurred where the soil surface was cracked compared to other locations where the soil surface was not cracked, even when liquids such as toluene were not used. it was concluded that the factors that significantly influenced the apl and napl migration were the structure of the soil sample, fracture pattern of the soil sample, physical interaction i.e. bonding between the liquid and soil sample, and the capillary pressure of the fluid. this study indicates that digital image analysis can provide detailed information to help researchers better understand and be able to simulate the pattern and characteristics of liquid migration that have an influence on groundwater resources. sity less than that of water. toluene is known as a light non-aqueous phase liquid (lnapl), and has been used in this study as a proxy for other hydrocarbon liquids. the structure of the soil affects the speed, rate, and pattern of liquid migration. under natural conditions, soil is typified by many different structures and hence is not a homogeneous medium. cracked soil increases the hydraulic conductivity and reduces the soil shear strength (fredlund et al., 2010). research by krisnanto et al. (2014) recognizes that fractured soil played an essential role in influencing the flow of liquids through problematic soil structures. in the same way, fredlund et al. (2010) stated that the mechanical properties and hydrological characteristics in cracked soils are significantly different. the term “double-porosity” refers to soil that displays two specific scales of porosity (carminati et al., 2008). double-porosity soil displays a pore-size bimodal distribution due to the conditions of intra-aggregate and inter-aggregate pores, which can be found in agricultural topsoil’s and compacted soil (li & zhang, 2009; el-zein et al., 2006). using first principles analysis, lakeland et al. (2014) verified that liquefaction is not a strictly undrained process. in fact, the interplay between soil rearrangement, permeability changes, and liquid migration leads to a loss of strength as detected in numerous examples of destructive earthquake situations. furthermore, masciopinto et al. (2001) demonstrated that fractured porosity formations were characterized by water-bearing formations where groundwater flows along fissures and fractures in the solid rock. the fractures article history: manuscript received december 19, 2017 revised manuscript accepted april 27, 2018 available online june 21, 2018 keywords: groundwater pollution, fracture porous media, saturation, liquid migration, digital image analysis. g eo lo gi a c ro at ic a geologia croatica 71/256 were a result of a fracture of the rock mass caused by tectonic forces, which is also known as an earthquake force. the dual-continuum method is more capable of dealing with a fracture-matrix interplay compared to the discrete-fracture model (fredlund et al., 2010). therefore, this study applied the model concept of a fractured double-porosity medium with the soil that overlaps the three continuums. these consist of fracture porosity, primary porosity and secondary porosity features as developed by loke et al. (2016). according to lewandowska et al. (2005), the double-porosity characteristics in soil could be generated in the laboratory, where most studies concerning double-porosity soil are carried out. furthermore, bagherieh et al. (2009) conducted a series of one-dimensional drying and consolidation experiments on laboratory-prepared aggregated kaolin samples. recently, a number of researchers (alazaiza et al., 2017; sitthiphat & siam, 2016; ngien et al., 2016; sa’ari et al., 2015; peng et al., 2015) have conducted experiments on double-porosity soil media that have contributed to the body of knowledge and understanding of soil characteristics. however, to the best of our knowledge, these studies were limited to the common intact double-porosity method and the effect of vibration imposed onto the double-porosity soil method was not implemented. based on the above, this experimental study uses kaolin soil to produce double-porosity soil characteristics in the laboratory. in malaysia, natural kaolin soil could be found in many states such as perak, johor, pahang, selangor, terengganu, kelantan, sabah and sarawak (seong, 2005). a powerful method used in many research areas is the image analysis method, which is used to investigate the complicated characteristics of contaminants and to determine the liquid saturation rate (luciano et al., 2010). therefore, this study used digital image analysis to understand and analyse the apl and napl migration in a fractured double-porosity soil. digital image analysis is a mode of analysis using a computer to obtain information and data from a digital image. the common ways to observe and monitor liquid migration involve many measuring apparatuses that may interfere with the original sample setup; however, using digital image processing techniques will overcome the problem using non-destructive and nonintrusive techniques. cnudde & boone (2013) found that image analysis is a reliable technique for the direct investigation and imaging of liquid migration in rock pore space. in this case, numerous researchers (alazaiza et al., 2017; ngien et al., 2016; zheng et al, 2015; bob et al., 2008; kechavarzi et al., 2008; bridge et al., 2007) have conducted non-intrusive image techniques for physical experiments in liquid migration analysis. porous and cracked soils are very hard to monitor with the naked eye, and for this reason, digital image processing analysis was suitable and acceptable for use in the study of the migration of liquids in fractured double-porosity soil. the difficult problem of gathering data concerning immiscible liquid movement characteristics and the appropriate physical experiments will help in the effort to comprehensively understand, monitor, observe, evaluate and solve groundwater contaminant problems (ngien et al., 2012). recent research by kristnanto et al. (2014) demonstrated the significance of understanding the flow behaviour through a cracked soil and suggested that further experimental studies on more complex crack patterns to investigate the liquid speed rate were required. therefore, a physical experimental model was conducted to study the characteristics of apl and napl migration in deformable double-porosity soil under the effects of vibration, by using digital image analysis. this study attempts to bridge the gap with the following objectives (i) to determine the behaviour of apl and napl migration in a fractured double-porosity soil using a digital image processing technique, (ii) to differentiate the pattern between apl and napl migration in fractured double-porosity soil, and (iii) to identify the apl and napl migration rate for a specific soil column circumference zone in the soil sample. 2. materials and methods in this study, details of the fracture double-porosity soil sample preparation, experimental setup and digital image processing setup are discussed in the following subsections. 2.1. fracture double-porosity soil sample preparation a commercially available artificial kaolin soil type s300 was used as the soil sample in this study to produce a double-porosity model. double-porosity displays the condition of intra-aggregate and inter-aggregate pores with different hydraulic properties in aggregated soil (maja et al., 2015). the kaolin soil properties were tested based on british standards bs1377-2: 1990 and bs1377-5: 1990 for the purpose of acquiring particle size distribution, atterberg limits, saturated permeability and soil particle density of the kaolin soil. the kaolin soil s300 properties are shown in table 1. the aggregated kaolin soil was prepared based on the method of loke et al. (2017) and bagherieh et al. (2009), where the dried kaolin powder was first mixed with water to produce a 25% moisture content for samples 1 and 2. distilled water is constantly poured when mixing the dried kaolin powder to control the moisture content within the mixture. the optimum moisture content for a kaolin s300 soil sample is 27%, whereas a 25% moisture content was chosen for this study. this is because the 25% moisture content was mouldable and not too wet to form the aggregate, while with a moisture content less than 25%, the kaolin was unable to form aggregates because the kaolin granules were too crumbly and dry (ngien et al., 2016). thereafter, the mixture was kept in a plastic bag to maintain the moisture content, and left to cure in cool conditions for a minimum of 24 hours in order to attain water content equilibrium. after the process of curing, the mixture was passed through a 2.36 mm sieve to obtain kaolin granules for the purpose of creating the double-porosity soil structure. the kaolin granules with a weight of 0.97kg were placed in an acrylic soil column and compressed to a height of 100 mm using a compaction machine at a compression rate of 1 kgf/cm2. the sample height of 100 mm was chosen to ensure uniformity throughout the soil sample depth. experiments were conducted on an acrylic soil column sealed base with dimension of 300 mm high x 100 mm-outer ditable 1. kaolin soil s300 properties. property value liquid limit (%) 40.50 plastic limit (%) 27.00 plasticity index (%) 13.50 particle density (mg/m3) 2.65 sand: 2mm to 0.06mm (%) 3 silt: 0.06mm to 0.002mm (%) 93 clay: smaller than 0.002mm (%) 4 uscs classification ml saturated permeability, k average (m/s) 5.41 x 10-9 g eologia c roatica foong et al.: study of aqueous and non-aqueous phase liquid in fractured double-porosity soil using digital image processing 57 ameter and 94 mm-inner diameter. the acrylic soil column has been custom designed to monitor and detect the phenomena occurring inside the whole area of the circular column. the acrylic soil column with kaolin granular “soil” was fixed and bolted onto the vibration table in order to prevent any random movement of the soil column during the vibration process. the setup of the vibration table used in the experiment was developed by loke et al. (2016) as shown in (fig. 1). moderate to low seismic activity, such as the magnitude 6.0 earthquake that struck ranau, malaysia on 5 june 2015 around 7:15 am is one of the examples used. this earthquake had a peak ground acceleration of 0.12g (harith et al., 2017). thus, based on the details, seismic activity and seismosignal software analysis display an approximate vibration frequency of only 0.95hz. therefore, a vibration frequency 0.98hz was adopted for this study. the double-porosity soil samples with 25% moisture content were placed on the vibration table and subjected to vibration frequencies following the loading protocol outlined by fema 461 (2007). the vibration frequency for the vibration table was set at a 0.98hz frequency and the vibration process duration was 60 seconds. this was twice as long as the 30 seconds real-time earthquake in order to simulate the worst case scenario based on the method and setup given by loke et al. (2016). the results of the fractured soil patterns before and after the vibration process for samples 1 and 2 (25% moisture content) are displayed in (fig. 2). the soil samples clearly display fracturing in the top region of the soil. thus, the concept of a fracture double-porosity phenomenon was to prove that in fact the vibration effect had caused the double-porosity soil to fracture. 2.2. experimental setup the fractured double-porosity in the soil column was used to measure and monitor the lnapl and water migration inside the whole circular column area with the aim of simulating groundwater contamination. the simulation did not interfere with the original soil sample as a digital image processing technique was used. in each sample, the experiment setup was arranged as shown in (fig. 3) for apl and napl migration image acquisition. a nikon d90 digital single lens reflex (dslr) camera was used for fluid migration image acquisition and the v shape reflection mirror was used to reflect the whole area of soil column image. the camera is equipped with a sensor size of 23.6mm x table 2. image acquisition frequency. duration (min) frequency interval (s) sample 1 sample 2 0 – 2 3 s 3s 2 – 4 5 s 5s 4 – 6 10 s 10 s 6 – 8 15 s 15 s 8 – 9 20 s 20 s 9 – 10 30 s 30 s 10 – 20 60 s 60 s 20 – 30 60 s 60 s 30 – 40 60 s – figure 1. vibration table setup (loke et al., 2016). figure 2. a) soil sample 1 before vibration process. b) soil sample 1 after vibration process with fracture. c) soil sample 2 before vibration process. d) soil sample 2 after vibration process with fracture. figure 3. digital image acquisition experiment setup. g eo lo gi a c ro at ic a geologia croatica 71/258 15.8mm and a medium size image format of 3216 x 2136 pixels was used resulting in each pixel having the size resolution of 5.6µm x 5.6µm. the camera, which also had a remote control, was used to capture images smoothly without vibration of the camera. the v shape mirror was set and adjusted until a clear image that allowed 100% of the soil column to be achieved. the experimental light source came from a linear fluorescent lamp40 watt with the light output luminous flux of 2600 lumens/watt, which was placed slightly above the soil column. both experiments began by pouring the liquid instantaneously (using the glass funnel with care to avoid damaging the soil surface) onto the top center fractured aggregated soil sample in the acrylic soil column. a volume of 70ml of distilled water (apl) and toluene (napl) were used in samples 1 and 2, respectively. the toluene and water in both experiments were dyed red using oil-red-o powder to enhance their visibility during the migration process. after the dyed water and toluene were poured onto the surface area of the fractured soil sample, the first digital image of fluid migration was taken. subsequent digital images were taken at specific time intervals to capture the fluid migration pattern for both experiments. sample 1 was recorded for a total of 36 minutes while sample 2 was recorded for 30 minutes based on the total time needed for the liquids to migrate the full depth of the soil column. using the image acquisition frequency given in table 2, a total of 115 images and 76 images were produced for sample 1 and 2, respectively. 2.3. digital image processing setup the digital image processing (dip) presents the use of computer algorithms to perform image processing on the digital images that have been captured. dip is a practical technology for classification, pattern recognition, feature extraction, projection, characteristics recognition, image editing, neural networks and multi-scale signal analysis. the recorded colour digital images were saved in jpeg format and transferred from the digital came ra to a computer for further image processing using a matlab routine and surfer software. surfer software can quickly and easily convert the matlab data into outstanding contours, surface, wireframe, vector, image, and post maps. the flow chart of dip is shown in (fig. 4). a matlab routine for digital image processing was used to extract an area of interest from the captured image and to transform that area of interest from a distorted image to a scale image via the affine transformation method. this involves converting the jpeg scale images to red green blue (rgb) and hue saturation intensity (hsi) images; then extracting the hsi digital value from the hsi image and saving the hsi value in a text file using american standard code for information interchange (ascii) format. the matlab routine coding © 2017 universiti teknologi malaysia – all rights reserved by “kfloke.l.m” as shown in (fig. 5). first, the surfer software was used to digitize the control point from the reference image to extract an actual true scale image coordinate as a control point. the area of interest refers to a pre-determined migration boundary area for samples 1 and 2 that contained the apl and napl as shown in (fig. 6). the matlab routine was then used to convert the area of interest into rgb and hsi image format, where the values were extracted and saved in ascii format. the matlab routine was repeated three times for the subsequent digital image to extract and save the intensity values for all three section areas of interest of the acrylic soil column. the matlab results were saved in a file along with the summary information of the digital image processing and displayed in the matlab command window as shown in (fig. 7). lastly, a map or plot contour pattern of the migration pattern of apl and napl in the fractured porous media using hsi values was generated. 3. results after the migration process for the top fractured soil surface with the actual size measurement, the column circumference zone was divided to visualize the crack position for sample 1 and 2 as shown in (fig. 8). based on the fig. 8 observation, it can be clearly observed that the soil structure was slightly different in terms of fracture pattern evolution and location of the fracture(s). the three-dimensional wireframe downward migration pattern of the hsi contour plots of dyed distilled water and toluene in the fractured double-porosity soil sample with 25% moisture content for samples 1 and 2, respectively, are shown in (fig. 9). it should be noted that the soil column experiment is practically one dimensional. however, due to random soil fracture, the migration pattern radially is not uniform. to capture this non-uniform migration pattern, the surface of the cylinder is unfolded to a flat 2d plot where the x-axis represent the column circumference while the y-axis is the soil depth. 3d wireframes are created by connecting z values along lines of x and y. a wireframe 3d model is a skeletal representation of the real migration phenomena and is characteristic of a double-porosity soil. the 3d modelling contour plot has a higher quality representation of the liquid migration as compared to a conventional 1d plot. in both samples, 70ml dyed apl and napl were poured instantaneously on the top centre of the soil sample surface to ensure that the dyed apl and napl penetrated in one-dimension. in both experiments, the flow of the water and lnapl migration was not uniformly downward at the front boundary horizontal line due to the inhomo geneity of the fractured double-porosity soil. in soil sample 1, the selected 3d wireframe hsi plots of dyed distilled water (apl) migration at intervals of 5, 180, 900, and 2160 seconds, respectively, can been seen in (fig. 9a). based on the 3d hsi intensity contour plot result, a faster migration ocfigure 4. the flow chart of digital image processing method. g eologia c roatica foong et al.: study of aqueous and non-aqueous phase liquid in fractured double-porosity soil using digital image processing 59 figure 5. matlab routine for l section named “kfloke.l.m”. g eo lo gi a c ro at ic a geologia croatica 71/260 figure 6. digitization of the control point for area of interest. figure 7. winding-up summary of the dip display in the matlab command window for l section area. figure 8. a) sample 1 (apl). b) sample 2 (napl) migrated soil surface with measurement of actual column circumference zone. g eologia c roatica foong et al.: study of aqueous and non-aqueous phase liquid in fractured double-porosity soil using digital image processing 61 curred at the cracked soil surface condition as compared to other locations on the soil surface that were not cracked in soil sample 1 as shown in (fig. 8a). the dyed water completely migrated over the whole top soil surface area into the fractured soil sample of the test, which took approximately 360 seconds. meanwhile, the duration for the dyed water migration from the top surface to the stop point was 2160 seconds and further observations at 3600 seconds indicated that no further changes in migration pattern had occurred where the apl migration between 90 to 150mm along the x-axis had migrated downward approximately 92% of the soil sample depth. after 5 seconds, the dyed apl had penetrated nearly halfway through the soil sample at the location of the fractured soil surface, as shown in fig. 9a. the deepest apl downward migration depth along the soil column was 92mm of the total length of the 100mm soil sample. the dyed distilled water (apl) migration stopped at 2160 seconds and did not fully migrate in this study because the water viscosity was 0.00089 kg/m/s, while toluene viscosity was 0.00055 kg/m/s, a viscosity figure 9. a) sample 1 (apl). b) sample 2 (napl) 3d wireframe hsi plots of downward migration in fracture double-porosity soil. g eo lo gi a c ro at ic a geologia croatica 71/262 difference of about 38% (assael et al., 2001 & joseph at al., 1978). thus, the dyed water caused the highest resistance and friction to gradual migration. in soil sample 2, intervals of 5, 180, 900 and 1800 seconds, respectively, were selected for the 3d wireframe dyed napl migration hsi contour plots as shown in fig. 9b. the napl migration was similar to the results found in sample 1. after 5 seconds, the dyed napl migration reached nearly halfway through the test sample at the location of the fractures in the soil surface as shown in fig. 8b. the lnapl completely receded from view over the whole top soil surface area into the fractured soil sample of the test, which took about 5 seconds. meanwhile, the overall duration for dyed water migration from the top surface to the bottom of the soil column was 1800 seconds and a further observation at 3600 seconds showed no changes in migration pattern where the napl migration fully reached the bottom of the soil column. the migration observation of sample 1 shows that the napl migration in sample 2 reached 100% of the soil column depth, but in contrast, the dyed water migration was the slower migration and did not fully reach the bottom of the soil column because water has a higher viscosity as compared to toluene. this could also be because the physical bonding between toluene and soil is weaker than that between water and soil. the physical bonding between toluene and soil was attributed to van der waals forces, which are weaker than hydrogen bonding, which has stronger physical bonding between water and soil. this was also one of the reasons why the water (apl) migration was slower than for the toluene (napl) migration. in previous research by sa’ari et al. (2015), an experiment on toluene migration in a double-porosity soil with 25% moisture content without vibration effect was performed, and the results showed that the toluene napl migration to the bottom took 2280 seconds compared to this study, where napl and apl migration took only approximately 1800 seconds and 2160 seconds, respectively, to reach the bottom of the soil column. this could be because the fracture that occurred at double-porosity loosened the soil structure in this study as compared to previous research migration in intact double-porosity that has a stronger and more compact soil structure. thus, this study supported the previous research by loke et al. (2017), which stated that the specific fractured double-porosity soil experienced a faster migration compared to the intact double-porosity soil. the measured values of dyed apl and napl migration, as a function of the column circumference, for the selected critical time interval in seconds are shown in figs. 10 and 11 for samples figure 10. measured values of apl migration depth as a function of the column circumference zone for selected critical time interval in seconds figure 10. measured values of apl migration depth as a function of the column circumference zone for selected critical time interval in seconds. figure 11. measured values of napl migration depth as a function of the column circumference zone for selected critical time interval in seconds figure 11. measured values of napl migration depth as a function of the column circumference zone for selected critical time interval in seconds. g eologia c roatica foong et al.: study of aqueous and non-aqueous phase liquid in fractured double-porosity soil using digital image processing 63 1 and 2, respectively. based on the results in fig. 10, the fastest and most critical migration downward depth of apl migration occurred between 90 to 140mm and 240 to 280mm along the soil column circumference within 5 seconds as demonstrated by the steep gradient of the graph within that duration. the significant difference is due to the condition of the fractured soil surface, compared to other locations on the soil surface, which were not fractured. meanwhile, the rest of the column circumference positions continue a slow, decreased migration from the start until the end of the experiment. based on the results shown in fig. 11, it was found that the cumulative migration depth of napl migration between 0 to 30mm and 260mm to 310mm along the column circumference, displayed the most critical migration downward within 5 seconds as shown by the steepest gradient on the graph within that duration. the napl migration sped up between 5 and 180 seconds, which shows a difference in the migration pattern. the speeding up of the napl is caused by high entry pressure at the top soil surface due to the weight of the liquid. meanwhile, the remaining column circumference positions displayed a slight decrease in napl migration from the start until the end of the experiment. the calculated migration speed rate for the higher and overall average speed for every 30 mm column circumference zone is demonstrated in table 3. sample 1 shows the higher migration speed rate from the start to 30 seconds was at the 270 mm co lumn circumference zone with a migration speed rate of 2.80 mm/s. the overall average dyed water (apl) migration rate for sample 1 is 0.09 mm/s. sample 2 displays the higher migration rate from initial to 30 seconds at 300 mm column circumference zone, with a migration speed of 4.07 mm/s. meanwhile, the overall average dyed toluene (napl) migration rate for sample 2 is 0.39 mm/s. this value is higher compared to the non-fractured soil condition (sa’ari et al., 2015). for both samples, the higher migration flow occurred at the column circumference position that displayed the larger fractured soil structure. 4. conclusions a physical laboratory experiment on apl and napl migration in a fractured double-porosity soil with 25% moisture content has been carried out. this laboratory experiment was intentionally designed to investigate and differentiate between the apl and napl migration characteristics and patterns in the fractured double-porosity soil placed in an acrylic circular soil column. the digital image processing technique using the matlab routine and surfer software was applied to extract and analyse the apl and napl migration data acquired from captured digital images. from the results observed, both experiments indicated that in comparison to the apl migration, the napl migrated faster from the top surface to the bottom of the soil column. the significant finding was that the napl had fully migrated to the bottom (100%), but the apl migration stopped at 92% of the soil column depth. liquid migration was observed to be faster for the fractured soil condition. this is because this study applied the effect of vibration on the double-porosity and the additional capillary force exerted by the fluid pressure on top of the fractured soil sample. from the results, it can be concluded that the factors that significantly influenced the apl and napl migration in samples 1 and 2, respectively, were the structure of the soil sample, the fracture pattern of the soil sample, viscosity of the liquid, physical interaction bonding between the liquid and the soil sample, and the capillary pressure of the fluid. in conclusion, this study indicates that the fractured double-porosity soil under a vibration effect with napl migration has very detrimental consequences for groundwater resources. the current model makes a more practicable contribution to future sustainable groundwater protection and remediation. acknowledgement this study was supported by the research management centre (rmc), universiti teknologi malaysia under research university grant – tier 1 (py/2016/06547) from the ministry of higher education, malaysia. the authors would also like to thank their respective university, public service department malaysia, geotechnical laboratory, hydraulic and hydrology laboratory, engineering seismology and earthquake engineering research group (eseer), and survey unit, faculty of civil engineering, universiti teknologi malaysia for their kind assistance in this research. the first author was supported through the federal training award by the public service department under prime minister’s department, malaysia. references alazaiza, m.y.d., ngien, s.k., bob, m.m., kamaruddin, s.a. & ishak, w.m.f. (2017): influence of macro-pores on dnapl migration in double-poro sity soil using light transmission visualization method.– transport in porous media, 117, 103–123. doi:10.1007/s11242-017-0822-3 assael, m.j., avelino, h.m.t., dalaouti, n.k., fareleira, j.m.n.a. & harris, k.r. (2001): reference correlation for the viscosity of liquid toluene from 213 to 373k at pressures to 250mpa.– international journal of thermophysics, 22/3, 789–799. doi:10.1023/a:1010774932124 bagherieh, a.r., khalili, n., habibagahi, g. & ghahramani, a. (2009): drying response and effective stress in a double porosity aggregated soil.– engineering geology, 105/1–2, 44–50. doi:10.1016/j.enggeo.2008.12.009 bob, m.m., brooks, m.c., mravik, s.c. & wood, a.l. (2008): a modified light transmission visualization method for dnapl saturation measurements in 2-d models.– advance water resource, 31, 727–742. doi:10.1016/j.advwatres.2008.01.016 bridge, j.w., banwart, s.a. & heathwaite, a.l. (2006): non-invasive quantitative measurement of colloid transport in mesoscale porous media using image lapse fluorescene imaging.– environment science technology, 37, 1859–1868. doi:10.1021/es060373l carminati, a., kaestner, a., lehman, p. & flühler, h. (2008): unsaturated water flow across soil aggregate contacts.– advances in water resources, 31/9, 1221–1232. doi:10.1016/j.advwatres.2008.01.008 cnudde, v. & boone, m. (2013): high-resolution x-ray computed tomography in geosciences : a review of the current technology and applications.– earth science reviews, 123, 1–17. doi:10.1016/j.earscirev.2013.04.003 el-zein, a., carter, j.p. & airey, d.w. (2006): three-dimensional finite elements for the analysis of soil contamination using a multiple-porosity approach.– international journal for numerical and analytical methods in geomechanics, 30/7, 577–597. doi:10.1002/nag.491 table 3. migration speed rate for every 30mm column circumference. column circumference zone (mm) migration speed rate (mm/s) soil sample 1 (apl) soil sample 2 (napl) higher flow between initial to 30 seconds average flow for all the time interval higher flow between initial to 30 seconds average flow for all the time interval 0 0.31 0.05 2.87 0.49 30 0.21 0.04 2.30 0.40 60 0.15 0.04 1.65 0.30 90 0.36 0.10 1.37 0.26 120 0.33 0.19 1.58 0.29 150 0.49 0.07 2.00 0.35 180 0.23 0.04 1.86 0.33 210 0.16 0.04 2.66 0.47 240 0.27 0.05 1.38 0.25 270 2.80 0.28 2.80 0.49 300 0.29 0.05 4.07 0.69 g eo lo gi a c ro at ic a geologia croatica 71/264 federal emergency management agency, fema 461 (2007): interim testing protocols for determnining the seismic performance characteristics of structural and nonstructural components.– applied technology council, redwood city, california. fredlund, d.g., houston, s.l., nguyen, q. & fredlund, m.d. (2010): moisture movement through cracked clay soil profiles.– geotechnical and geological engineering, 28/6, 865–888. doi:10.1007/s10706-010-9349-x harith, n.s.h., adnan, a. & shoushtari, a.v. (2017): deaggregation of probabilistic ground motions in the kota kinabalu and lahad datu towns of sabah, malaysia.– matec web of conferences. seoul, south korea, 09001, 2–11. doi:10.1051/matecconf/201713809001 joseph, k., mordechai, s. & william, a.w. (1978): viscosity of liquid water in the range 8oc to 150oc.– journal phys. chem. ref. data, 7/3, 941–948. doi:10.1063/1.555581 kechavarzi, c., soga, k., illangasekare, t.h. & nikolopoulos, p. (2008): laboratory study of immiscible contaminant flow in unsaturated layered sands.– vadose zone journal, 1–9. doi: 10.2136/vzj2006.0177 krisnanto, s., rahardjo, h., fredlund, d.g. & leong, e.c. (2014): mapping of cracked soils and lateral water flow characteristics through a network of cracks.– engineering geology, 172, 12–25. doi:10.1016/j.enggeo.2014.01.002 lakeland, d.l., rechenmacher, a. & ghanem, r. (2014): towards a complete model of soil liquefaction: the importance of fluid flow and grain motion.– proceedings of the royal society a – mathematical, physical and engineering sciences, london a470:20130453. doi:10.1098/rspa.2013.0453 lewandowska, j., szymkiewicz, a., gorczewska, w. & vauclin, m. (2005): infiltration in a double-porosity medium: experiments and comparison with a theoretical model.– water resources research, 41/2, w02022. doi:10.1029/2004wr003504 li, x. & zhang, l.m. (2009): characterization of dual-structure pore-size distribution of soil.– canadian geotechnical journal, 46, 129–141. doi: 10.1139/t08-110 loke, k.f., rahman, n.a. & nazir, r. (2017): experimental study on unsaturated double-porosity soil phenomena under vibration effect.– jurnal teknologi, 79/4, 65–72. doi:10.11113/jt.v79.9976 loke, k.f., rahman, n.a. & ramli, m.z. (2016): a laboratory study of vibration effect for deformable double-porosity soil with different moisture content.– malaysian journal of civil engineering, 28, si/3, 207–222. luciano, a., viotti, p. & papini, m.p. (2010): laboratory investigation of dnapl migration in porous media.– journal of hazardous materials, 176, 1006–1017. doi:10.1016/j.jhazmat.2009.11.141 maja, i., neda, v., sandra, d.b.b., vladimir, b. & ivan, s. (2015): mineralogy, surface properties and electrokinetic behaviour of kaolin clays derived from naturally occurring pegmatite and granite deposits.– geologia croatica, 68/2, 139– 145. doi: 10.4154/gc.2015.09 masciopinto, c., benedini, m., troisi, s. & straface, s. (2001): conceptual models and field test results in porous and fractured media in groundwater pollution control.– wit press, southampton, uk. ngien, s.k., chin, p.q., hasan, m., ali, m.i., tadza, m.y.m. & rahman, n.a. (2016): image analysis of non-aqueous phase liquid migration in aggregated kaolin.– arpn journal of engineering and applied sciences, 11/10, 6393–6398. ngien, s.k., rahman, n.a., ahmad, k. & lewis, r.w. (2012): a review of experimental studies on double-porosity soils.– scientific research and essays, 7/38, 3243–3250. doi:10.5897/sre11.2131 ngien, s.k., rahman, n.a., bob, m.m., ahmad, k., sa’ari, r., & lewis, r.w. (2011): observation of light non-aqueous phase liquid migration in aggregated soil using image analysis.– transport in porous media, 92/1, 83–100. doi: 10.1007/s11242-011-9892-9s peng, z., duwig, c., delmas, p., gaudet, j.p., strozzi, a.g., charrier, p. & denis, h. (2015): visualization and characterization of heterogeneous water flow in double-porosity media by means of x-ray computed tomography.– transport in porous media, 110, 543–564. doi:10.1007/s11242-015-0572-z sa`ari, r., rahman, n.a., latif abdul, n.h., yusof, z.m., ngien, s.k., kamaruddin, s.a., mustaffar, m. & hezmi, m.a. (2015): application of digital image processing technique in monitoring lnapl migration in double porosity soil column.– jurnal teknologi, 3/72, 23–29. doi:10.11113/jt.v72.4018 seong, k.p. (2005): sustainable mining of the clay resources in peninsular malaysia.– geological society of malaysia bulletin, 51, 1–-5. sitthiphat, e.a. & siam, y. (2016): investigation of average optical density and degree of liquids saturation in sand by image analysis method.– kku eng. journal, 43/s1, 147–151. doi:10.14456/kkuenj.2016.44 yousef, h.n., nassir, s.n.a.a., muhammad, k.j., hossam, a.k., habes, g., mahmoud, m.e.w., awni, b. & taisser, z. (2015): multivariate statistical analysis of urban soil contamination by heavy metals at selected industrial locations in the greater toronto area, canada.– geologia croatica, 68/2, 147–159. doi:10.4154/gc.2015.10 zheng, f., gao, y., sun, y., shi, x., xu, h. & wu, j. (2015): influence of flow velocity and spatial heterogeneity on dnapl migration in porous media: insights from laboratory experiments and numerical modelling.– hydrogeology journal, 23, 1703–1718. doi:10.1007/s10040-015-1314-6 www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2025 | 78/2 | 129–139 | 6 figs. | 3 tabs. | 1. introduction water is the most vital natural resource for the existence of life and the sustainability of ecosystems (macdonald et al., 2016). water quality is controlled by the concentration of dissolved elements and ions, constituting an integral part of its chemical composition (adetoyinbo et al., 2010; singh et al., 2008). groundwater is an important source of available freshwater across the globe. however, groundwater quality deteriorates due to many anthropogenic and geogenic factors contributing to freshwater contamination (talib et al., 2019). the contaminants in groundwater are leading cause for waterborne health issues worldwide (hashmi, 2000; li et al., 2021). according to the un environment programme, about 80% of the world’s wastewater, containing toxic chemicals and human waste, is discharged into the ecosystem without any treatment (lin et al., 2022). the yearly un world water development report, states that around 1.7 billion people worldwide use contaminated drinking water (un-water, integrated assessment of groundwater quality, agriculture suitability and health risk assessment in the upper indus basin, district gujranwala, pakistan faisal rehman1,*, mishal razaq1, tahir azeem1, muhammad toqeer1, haleema saeed1, jamil siddique1, syeda mahwish1, faisal rehman2 and salman mustafa1,3 1 quaid-i-azam university, department of earth sciences, islamabad, pakistan; (*corresponding author: frehman@qau.edu.pk; mishalrazaq451@gmail.com; mishalrazaq45@gmail.com; tazeem@qau.edu.pk; mtouqeer@qau.edu.pk; haleema1@geo.qau.edu.pk; jamils@qau.edu.pk; mahwishmzhr21@gmail.com; salman.1097@hotmail.com) 2 sargodha university, department of earth sciences, sargodha, pakistan; (faisal.rehman@uos.edu.pk) 3 land information and management system, strat projects, ghq, rawalpindi, pakistan doi: 10.4154/gc.2025.07 abstract public health protection, sustainable agricultural practices, and environmental degradation mitigation, all depend on the quality of groundwater. groundwater quality remains a critical concern in the densely populated cities of pakistan. integrated assessment of groundwater quality in an area provides a comprehensive understanding to support effective resource management and policy-making. the focus of this study is to evaluate the ionic concentration of groundwater and subsequent consequences based on twenty-eight groundwater samples acquired from different water schemes in the gujranwala district, punjab, upper indus basin, pakistan. this study analyzes the type of ions, the effect of contamination on agriculture and groundwater contamination-based health risks. results show that the concentration of major ions in nearly all the groundwater samples lies within world health organization (who) limits except for arsenic (as). in about 64% of the total samples, the arsenic concentration exceeds the limit recommended by who which is 10 μg/l. the chemical composition of groundwater is influenced by rock weathering according to the gibbs plot. magnesium, bicarbonate, and sodium ions contribute to the groundwater's total dissolved solids as indicated by a piper plot. most of the water samples are suitable for irrigation purposes, except magnesium hazard values of about 57% substantially impact soil alkalinity. hazard quotient (hq) and carcinogenic risk (cr) assessments were also used in the study. the hq values in the study area lie in the range of 0.012 to 4.97, with an average value of 1.21, and about 57% of samples exceed the toxic risk index values. the cr value range is 5.41667×10-6 to 0.001, indicating a serious health threat to the residents in the area. prolonged use of arsenic-contaminated water will cause severe health issues for the area's residents. appropriate remedial and preventive actions should be undertaken to mitigate arsenic pollution in the area. 2021). among the common contaminants in groundwater include arsenic (as), nitrate, iron, and manganese (ahmed et al., 2019; zhang et al., 2020). every physical state was declared as a severe risk to human health by the united states environmental protection agency (sarkar & rupali, 2007; us-epa, 2005). the consumption of groundwater contaminated with as for a prolonged period can have dire con sequences, resulting in bladder cancer, hyperkeratosis, coro nary heart disease, bronchiectasis and arsenicosis (mazum der, 2008; shaji et al., 2021). groundwater contaminated with as has been confirmed in about more than 105 countries of southeast asia, including pakistan (smedley, 2008). in pakistan, the percentage of groundwater with significant as contamination reaches about 9%. around 25% to 36% of residents of the sindh and punjab provinces of pakistan are consuming water polluted with as (zubair et al., 2018). punjab holds the most significant groundwater reservoirs in pakistan. the sediments in the indus plain are alluvial and article history: manuscript received: february 27, 2024 revised manuscript accepted: february 6, 2025 available online: june 30, 2025 keywords: agriculture, groundwater, arsenic, contamination, gujranwala, health risk mailto:frehman@qau.edu.pk mailto:mishalrazaq451@gmail.com mailto:tazeem@qau.edu.pk mailto:mtouqeer@qau.edu.pk mailto:haleema1@geo.qau.edu.pk mailto:jamils@qau.edu.pk mailto:mahwishmzhr21@gmail.com mailto:faisal.rehman@uos.edu.pk g eo lo gi a c ro at ic a 130 geologia croatica 78/2 deltaic, and their thickness varies in different parts of the plain. the groundwater aquifers in the indus plain mostly lie in the quaternary sedimentary deposits. elevated as concentrations were reported in the aquifers within the sedimentary deposits of this area (smedley, 2008; ali et al., 2019b). of the 40 million people living in the 27 districts of pakistan, about 13 million are exposed to drinking water contaminated with as (ali et al., 2019b). moreover, it is reported that 656 villages and 6,173,680 people are facing serious risk of as poisoning (ali et al., 2019a, b). in the jhelum and chakwal regions of punjab province, coal mining and anthropogenic activities are the main sources of as contamination (ullah et al., 2023). in the tharparkar desert of sindh province, the reductive dissolution of as and fluoride ion induced by the arid environment and complex geology led to contamination of 100–2580 μg/l in the groundwater sources (brahman et al., 2013). according to (rabbani et al., 2017) in the thari mirwah, kot digi, sobo dero, and kingri regions, the alluvial deposits of the indus is the main factor that affects the groundwater quality. to evaluate the suitability of groundwater quality, various hydro-chemical methods have been applied worldwide. many integrated approaches help delineate the causes and effects of deteriorating water quality (ashraf et al., 2018). consequently, identifying the concentra tion of ion-causing contamination and its source is the key aspect to comprehending the pattern of groundwater con ta mination and the associated health risk impact of any region (sappa et al., 2014). the evolution of surface water chemistry has been summarized by gibbs (1970) based on the analysis of samples collected from rainfall, lakes, rivers, and oceans of different regions. the gibbs diagram was originally developed to study surface water chemistry and the main governing processes of water chemistry, including evaporation, precipitation, and water-rock interactions (marandi & shand, 2018). the gibbs plot, however, may overlook the groundwater controlling mechanism, i.e., the geochemical processes and environmental factors which lead to the concentration of certain minerals and ions (alley et al., 1998; marandi & shand, 2018). to deal with this problem, hydrochemistry is further analyzed using the piper plot (merino et al., 2021; peeters, 2014). according to piper (1944), the triangular diagram evaluates the relationship between aquifer rock types and water composition (kumar, 2013). water quality for agricultural processes depends upon the concentration of the minerals dissolved in the water uptake by plants from soil (wilcox, 1958). an appropriate balance of each ion and mineral is necessary for better crop yields. to circumvent the accumulation of salt around the plant roots and soil deprivation, an appropriate balance of salt is necessary (letey et al., 2011; skaggs et al., 2012). prolonged usage of poor-quality water will not only affect crop production but also cause alkalinity and salinity in the region (shakir et al., 2002). the electrical conductivity method provides the crucial assessment of salinity hazard impacting the quality of water used in irrigation (abbas et al., 2015). consequently, the ratio of sodium (na) with respect to magnesium (mg) and calcium (ca) in water, also known as sodium-adsorption-ratio (sar) is sensitive to the permeability of the soil and provides information on the effect of infiltration rate on agriculture (tadesse et al., 2009). na is among the most important cations an excess of which can lead to a reduced crop yield (narsimha, 2012). kelly's ratio and na percentage also govern the impact of excessive na in water used for agricultural purposes (sudhakar & narsimha, 2013). similarly, a surplus of mg ion in the soil is responsible for alkalinity, which reduces crop production and is assessed through mg hazard analysis. therefore, the health risk assessfigure 1. the map of pakistan with the location and detailed section of the gujranwala district. g eologia c roatica 131rehman et al.: integrated assessment of groundwater quality, agriculture suitability and health risk assessment in the upper indus basin ... ment associated with the presence of certain contami nants in the water is vital (celebi et al., 2014). to assess the threat caused by various elements immersed in water, the u.s. environmental protection agency (us-epa) proposes the hazard quotient (hq) analysis (eid et al., 2024). this study investigates several physico-chemical parameters to detect the presence of ions or elements affecting the groundwater quality of the gujranwala district using statistical analysis and graphical techniques. these coordinated techniques enable the identification of the variables influencing the hydrochemistry of groundwater and produce more meaningful results for effectively managing water resources. the findings from this study can give us fundamental knowledge on the quality of the groundwater in the study area and may help with implementing sensible water quality management strategies. 2. study area the gujranwala district is located in the plains of punjab, upper indus basin, pakistan. the geographic coordinates of gujranwala are 32°9'58.8636''n, 74°11'45.2400''e with an area of 3,622 km² an average elevation of 231 m (758 ft) and hosting a population of 6,011,066 (2017 census). gujranwala is the 5th largest city in pakistan. adjacent regions of the gujranwala district are the gujrat, sialkot, mandi bahauddin, hafizabad and sheikhupura districts. it sits at the upper part of rachna doab, which is the piece of land between two rivers: the chenab and ravi, running from the northeast to the southwest. rachna doab is part of the indo gangetic plain, filled with alluvium. the population density of the gujranwala district is about 932 per sq. km. the main water source is groundwater which can be drawn by installing tube wells. the average water depth is almost 16.76 metres, and the depth of tube wells varies from 137–198 metres (greenman et al., 1967). the climate conditions of the district are moderate, with temperatures reaching up to 40 ⁰c in summer while the temperature can drop down to 5 ⁰c during the coldest part of the winter (janjua et al., 2021). 3. geology and hydrogeology of the study area the study area lies in the upper indus basin, pakistan. gujranwala lies in the upper part of rachna doab, which consists of alluvial deposits of tertiary age overlapping an older rock formation. lithological units in the upper part of rachna doab consist of silt, medium to fine-grain sand and clay, which the indus river and its tributaries deposit. recurring floods and meandering of river channels, along with the rate of change of flow across the land surface, have caused recent deposition. the soil texture chiefly ranges from medium to coarse grain with permeable aquifers (greenman et al., 1967). the sediments in the indus plain are alluvial and deltaic, and their thickness varies in different parts of the plain. the groundwater aquifers in the indus plain mostly lie in the quaternary sedimentary deposits (smedley, 2008; ali et al., 2019b). the historical river dynamics during the shekhupura aggradation stage, when the river originally flowed near sialkot through gujranwala to shahkot, generating broad floodplains between hafizabad and sheikhupura, have formed the hydrogeology of the gujranwala area. it is possible to identify at least three channels from this phase that demonstrate a steady westward migration. the sand, silt, and clay deposits of the floodplain are similar to the contemporary chenab river deposits and indicate high groundwater potential because of well-developed alluvial aquifers. a river as extensive as the current chenab is indicated by huge meander scars, indicating significant water flow and sediment transport under current climate conditions. these historical processes have produced alluvial aquifers with improved groundwater recharge and storage which are important for the management of the area's water resources (kazmi & jan, 1997). the high-yield aquifers are mostly deep, unconfined, and relatively homogeneous in the study area, while anisotropy is due to the presence of clay which causes lower vertical permeability than horizontal in the strata. the impermeable basement rocks provide the lower boundary of the groundwater reservoir. the specific yield of a sandy aquifer is 0.15 m, the clay layer is 0.06 m, and the hydraulic conductivities mean values range from 1.5e-5 m/s and 1.2e-3 m/s in the vertical and horizontal directions, respectively, in the inter-fluvial region of the rachna doab (greenman et al., 1967). 4. data set and methodology 4.1. groundwater sampling qualitative assessment of the groundwater in the district provides insight into determining the contamination caused by hazardous elements in the water. twenty-eight groundwater samples were taken from eighteen functional government schemes and three non-functional schemes to estimate the quality of groundwater supply schemes in the gujranwala district. functional government schemes are referred to as sources of water supply from boreholes to the surrounding community, while nonfunctional are not currently providing any water services. a total of twenty-one water schemes as shown in figure 2, were observed from which some were resamp led therefore acquiring a total of twenty-eight groundwater samples. from the twenty-one schemes, three of them, namely, nizaam abad, rasool nagar, and wandah were nonfunctional while the rest were functional. collecting the groundwater samples from each location was handled carefully to ensure the reliability of the data for water quality assessment. to collect water samples, bottles were properly decontaminated and cleaned. nitric acid was used to rinse the 1.5-litre sample bottles i.e., polythene bottles. samples were collected into two bottles. some important parameters, including electrical conductivity (ec), total dissolved solids (tds) and ph were determined by a portable tds meter in the field as soon as the samples were collected while the detailed analysis for water quality was carried out in the pakistan water resources research council (pcrwr) laboratory. collected samples were handled carefully and transported to prevent surficial reactions that could cause sample contamination. 4.2. methodology the physico-chemical properties of groundwater samples, collected from gujranwala district are examined through a g eo lo gi a c ro at ic a 132 geologia croatica 78/2 statistical summary that represents the concentrations of ions dissolved in groundwater, their comparison with maximum allowed limit proposed by the who and other hydrogeological parameters including hardness, ph, turbidity, electrical conductivity (ec), bicarbonates (hco3 −), chloride (cl−), carbonates (co3 2−), sulfate (so4 2−), magnesium-ion (mg2+), calcium-ion (ca2+), potassium-ion (k+), sodium-ion (na+), nitrate (no3 −), fluoride (f−), iron (fe), phosphate (po4 3−) and arsenic (as). the gibbs diagram is inferred by analyzing the scatter plots for cations and anions, displayed by the (na+k)/ (ca+na+k) ratio, which are plotted against total dissolved solids (salinity) for cations (fig. 3a) and cl/(cl+hco3 −) ratios are plotted against total dissolved solids (salinity) for anions (fig. 3b) respectively (marandi & shand, 2018). the piper diagram represents the major anions and cations percentages plotted on a separate triangle in a milli-equivalent unit, the overall character of water is determined by points projected into the central diamond field (sajil kumar p.j., 2012). for assessment of groundwater quality used for irrigation purposes sar analysis, salinity index, kelly’s ratio, magnesium-hazard ratio (mh) and na percentage (na%) were carried out. the soil permeability varies with sar, which is the measure of the relative concentration of na, ca and mg and is quantitatively calculated by the formula given in equation (1) (marghade et al., 2011): sar na ca mg = + + + +2 2 2 � (1) based on electrical conductivity values, qualitative analysis for determining the salt content in the water samples, and salinity hazard analysis was carried out (abbas et al., 2015; cardon et al., 2003; bauder et al., 2011). kelly's ratio and the na percentage also govern the impact of excessive na in water used for agriculture. kr and na% are quantitatively calculated using equations (2) and (3), res pec tively (sudhakar & narsimha, 2013). kr ca mg = + + + + na 2 2 (2) na na k ca mg na k % = + + + + × + + + + + +2 2 100 (3) mh is also known as the magnesium hazard or magnesium adsorption ratio. the presence of a higher mg content affects the soil quality, making it more alkaline, and affects crop yield (sudhakar & narsimha, 2013). the formula for mh is given in equation (4) as: mh mg ca mg = + × + + + 2 2 2 100 (4) figure 2. location map of groundwater samples collected from water schemes in the gujranwala district. g eologia c roatica 133rehman et al.: integrated assessment of groundwater quality, agriculture suitability and health risk assessment in the upper indus basin ... the concentration of all the parameters used in the above equations (1), (2), (3), and (4) are in meq/l units. health risk analysis was carried out to estimate the health implications of prolonged consumption of as-contaminated water with reference to average daily dose (add), the hq, and carcinogenic risks (cr). add can be assessed using us-epa derived model. the average daily dose of as intake through water was calculated using equation (5) (rehman et al., 2020; shahid et al., 2018; tabassum et al., 2019; us-epa, 2001). add c ir ed ef bw at = ∗ * * * (5) here, as concentration (in mg/l) is denoted by c, ir stands for water consumption rate (approximate 2 l/day), exposure duration is denoted by ed (approximately 67 years according to the literature), exposure frequency (365 days/ year) is denoted by ef, bw symbolizes average body weight (72 kg) and average life cycle (24,455 days) is represented by at (rehman et al., 2020; shahid et al., 2018; tabassum et al., 2019). hq was calculated in order to estimate the non-cancerous health concerns triggered by the consumption of as polluted groundwater using equation (6) (rasool et al., 2017; iris, 2011; us-epa, 2001; tabassum et al., 2019): hq add rfd = (6) the as oral reference dose is denoted by rfd and taken as 0.0003 mg/kg/day. samples with hq values < 1 mg/kg/day are considered safe, while samples > 1 mg/kg/day pose serious health concerns. carcinogenic threats related to as in groundwater are well documented and pose serious health risks for humans. cancer risk was estimated by equation (7) (us-epa, 2001): cr = add*csf (7) here cr represents the cancer risk, and the slope factor is denoted by csf. 5. results and discussion 5.1. statistical analysis the distribution of different hydro-chemical parameters examined in the gujranwala district compared to the who recommended limits in groundwater samples are listed in table 1. the groundwater samples from the gujranwala district are mostly slightly alkaline with ph values ranging from 7.00 to 8.06 with an average of 7.6 and all the collected samples lie within the maximum threshold limit (table 1). values of electrical conductivity range from 499–1140 µs/cm with an average value of 672.9 µs/cm (table 1), indicating that the values in all the groundwater samples are within the maximum allowed limit. furthermore, f luoride, sulfate, hardness, bicarbonate, potassium, magnesium, ph, chloride, and sodium in all 28 samples are within the standard limit described by who (table 1). in three samples, the concentration of iron is high (table 1). the as concentration ranged from 0.13 to 53.75 μg/l with an average of 13.14 μg/l (table 1). however, the maximum allowed limit suggested by who is 10 μg/l, so the as contamination in the region is quite alarming around 64% of all samples (table 1). table 1. summary of important parameters in the groundwater samples and comparison with who standards. observed parameters units minimum value maximum value average maximum concentration limit (who, 2011; who, 2017) % age within a limit % age exceeds the limit ec μs/cm 499 1140 672.9 1500 100 _ ph – 7 8.06 7.6 6.5–8.5 100 _ tds mg/l 182 848 392.3 1000 100 _ hco3 − mg/l 135 390 298.8 350 100 _ co3 2− mg/l nil nil nil 200 100 – cl− mg/l 2 142 16 250 100 _ so4 2− mg/l 2 179 29.9 400 100 _ ca2+ mg/l 20 64 43.6 300 100 _ mg2+ mg/l 13 58 30.4 150 100 _ hardness mg/l 140 310 232.9 500 100 _ na+ mg/l 14 180 51.5 200 100 _ k+ mg/l 2.2 11.7 5.17 10 100 _ no3 − mg/l 0.1 1 0.49 45 100 – po4 3− mg/l 0.002 0.1 0.04 0.3 100 _ f− mg/l 0.11 0.64 0.30 1.5 100 _ fe mg/l 0.03 0.41 0.14 3 89 11 as μg/l 0.13 53.75 13.14 10 36 64 g eo lo gi a c ro at ic a 134 geologia croatica 78/2 5.2. formation mechanism of groundwater chemistry two subplots were generated representing cations and anions controlling factors, as (na+k)/(na+k+ca) were plotted as a function of total dissolved solids (tds) and cl/(cl+hco3 −) as a function of tds, respectively as shown in figure 3. the data points on the gibbs diagrams for cations and anions suggest that the groundwater chemistry is controlled principally by the predominant rock type. a piper plot was developed in the study area from the geochemical data from the analyzed groundwater samples (fig. 4). the piper plot shows most of the cations are present in the c zone, a few samples lie in the zone of no dominance and two samples lie in the na type representing that the groundwater sample in the gujranwala area is mainly of the “mg type” cation chemical composition. while anion samples frequently lie in the e zone, that is the “bicarbonate type” except for two samples in the no dominance zone. nearly all the samples are figure 3. a) the cation-based gibbs plot indicating the controlling factors of the groundwater chemistry of the samples; b) the anion-based gibbs plot indicating the controlling factors of the groundwater chemistry of the samples. figure 4. the type of ions present in the acquired groundwater samples indicated by the piper plot. g eologia c roatica 135rehman et al.: integrated assessment of groundwater quality, agriculture suitability and health risk assessment in the upper indus basin ... present in zone 3, and two samples are plotted in zone 2. so, in the study area hco3 & na+ are abundant ions. the geology and mineral composition of the punjab plain have a significant impact on the groundwater in the area. the punjab plain, part of the larger indo-gangetic plain, sits atop a complex alluvial structure deposited during the mid-tertiary period in a tectonic trough. this diverse alluvial complex, largely composed of fineto medium-grained sands, silts, and clays, reflects the dynamic processes of the indus river and its tributaries. notably, the presence of calcium carbonate concretions within the fine-grained sediments points to extensive secondary mineralization activities. the interaction between water and the mineral components of the sediment in this area influences the geochemical processes that dictate the composition of the groundwater. the presence of mg cations in the groundwater is attributed to the dissolution of dolomite and magnesite rocks, while the prevalence of bicarbonate anions is a result of the dissolution of calcite and the reaction of carbon dioxide with water. the groundwater in this region is likely to be slightly alkaline due to presence of dissolved carbonate minerals and contributes to its bicarbonate-rich composition. the characteristics of groundwater are significantly influenced by hydrogeological factors. in the punjab plain, the alluvial deposits give rise to an exceptionally permeable aquifer system, resulting in unconfined groundwater. the flow and residence time of groundwater is affected by the permeability and heterogeneity of the alluvium, which is determined by the scattered distribution of fine-grained mate rials and local clay bodies. in summary, the distinct mineralogical composition, hydro-geochemical processes, and geological heritage of the punjab plain collectively inf luence the groundwater composition within the region. the chemical constituents of groundwater are determined by its interaction with heterogeneous alluvial sediments and the hydrogeological attributes of the aquifer. 5.3. agriculture potential of the study area the quality of groundwater used for irrigation has an important impact on the yield of crops. depending on the aquifer's exposure to the type of contaminant materials, groundwater may become polluted with domestic, agricultural, or industrial waste due to using fertilizers, pesticides, and other harmful chemical products. classification of the groundwater based on electrical conductance values shows that 78% of the water samples (22 out of 28) lie in this range of 271–750 μs/cm, which is considered as good quality water for irrigation (narany et al., 2014), while the other 21% of water samples falls in the permissible range. data of ec of the study area represent the range from 499 to 1140 μs/cm. the relative concentration of na content in groundwater was assessed through the sar analysis and it depicts that all the values of sar lie in the excellent water quality range used for irrigation as from table 2 we can infer that all the groundwater samples are lying in the range <10. na percentage values of the region indicate that around 7% of samples fall in the range of doubtful water quality, 10% of samples lie in the permissible range and 65% of samples are considered as good quality water. kelly’s ratio is basically used to assess groundwater quality used for irrigation purposes. by analyzing kelly’s ratio values from table 2, it is clear that 25 out of 28 samples (89% of samples) are considered as suitable for irrigation purposes and the remaining 3 samples lie in the marginally suitable range. in natural water, mg and ca are in a state of equilibrium if either one of these cations has high values it can increase the ph of the soil and reduce the infiltration capacity of the soil, which has a really bad impact on crop yield. as the mg percentage was found to be high in the collected samples, the mh ratio was evaluated in this study. based on the mh ratio, it is concluded that 12 out of 28 lie in the suitable range while the remaining 57% of samples have mh ratio values greater than 50, so they are considered harmful, affecting the soil. 5.4. spatial distribution of as concentration map of the gujranwala area arsenic concentrations calculated in groundwater of the gujranwala area range from 0.13 to 53.75 μg/l with an average table 2. outcomes of the agriculture analysis carried out for the acquired groundwater samples. electrical conductivity water quality range no. of samples % age of samples excellent 0–250 – – good 271–750 22 79% permissible 751–2250 6 21% high 2251–6000 – – very high 6001–10000 – – extremely high 10001–20000 – – sar quality range no. of samples % age of samples excellent <10 28 100% good 10–18 – – doubtful 19–26 – – na percentage quality range no. of samples % age of samples excellent <20 5 18% good 20–40 18 65% permissible 40–60 3 10% doubtful 40–60 2 7% unsuitable >80 – – kelly ratio quality range no. of samples % age of samples suitable <1 25 89% marginally suitable 1–2 3 11% unsuitable >2 – – mg ratio quality range no. of samples % age of samples suitable <50 12 43 harmful >50 16 57 https://link.springer.com/article/10.1007/s12517-016-2340-y#ref-cr23 g eo lo gi a c ro at ic a 136 geologia croatica 78/2 figure 5. a map depicting the concentration of arsenic indicates that the shades of blue and purple colour depict a contaminated area. the orange colour indicates a moderate concentration of as while the pink indicates a low as value. figure 6. the hq map with potential health risks indicated by red color. g eologia c roatica 137rehman et al.: integrated assessment of groundwater quality, agriculture suitability and health risk assessment in the upper indus basin ... of 13.14 μg/l. almost 36% of samples lie within the safe limits described by the who, while 64% of samples are considered to exceed the safe limit. the spatial distribution of as concentration in the study area is shown in figure 5. among the 28 water samples, 18 have as values higher than the maximum allowed limit described by the who. 5.5. health risk assessment the current research study results show that the average daily dose ranges from 3.61e-6 to 1.49e-3 mg/kg/day with an average of about 3.73e-4 mg/kg/day. the hq values of samples collected from the study area range from 0.012 to 4.97, with 1.21 as the average value. almost 43% of the collected samples have hq values within the threshold limit (i.e., “1”) while the rest of the 57% of samples exceed the toxic risk index. so, based on the overall results of “hq” it is suggested that there is a substantial risk of as poisoning in the study area. the carcinogenic risk due to as contamination ranges from 1.11e-3 to 5.41e-6. based on the above health analysis, we can conclude that the inhabitants of gujranwala are subjected to a substantial health risk from as contamination in the collected groundwater samples. conclusion a study of 28 groundwater samples from gujranwala district revealed that 64% of them have exceeded who arsenic levels. sodium, magnesium, and bicarbonate are the dominant ions. while 79% of the samples are irrigable, 57% are too rich in magnesium, which is a threat to soil health. health testing shows high risk, where 57% are above the toxic risk index. the hydrogeological characteristics of the punjab plain are significantly influenced by its geological formation, comprising a quaternary alluvial complex deposited within a tectonic depression. this geological setting gives rise to a diverse aquifer composed of predominantly fineto medium-grained sand, silt, and clay. the composition of groundwater is largely inf luenced by geochemical processes, particularly the weathering of rocks. when carbonate minerals including dolomite and calcite dissolve, the predominant ions in the groundwater are magnesium (mg), bicarbonate (hco3), and sodium (na). hydrogeological conditions, notably the high permeability of the uppermost alluvial deposits, facilitate the movement of groundwater and engender substantial interaction between water and rock, resulting in the enrichment of groundwater with dissolved minerals. in conclusion, the composition of groundwater in the gujranwala district is inf luenced by a intricate interplay of mineral content, geochemical processes, and geological structures. the quality and chemical composition of the groundwater are shaped by its interaction with alluvial sediments and the hydrogeological characteristics of the aquifer. this has significant implications for its suitability for drinking and irrigation purposes. acknowledgment the authors acknowledge the pakistan council for research in water resources (pcrwr) for giving material support. references abbas, h.h., rashed, h.s. & el-zaeaty, d.e.d.a. (2015): assessment of waste waters quality for irrigation purposes.– annals of agricultural science, moshtohor, 53/4, 765–774. http://doi.org/10.21608/assjm.2015. 109961 adetoyinbo, a., adebo, b. & alabi, a. (2010): hydrochemical investigation of groundwater quality in selected locations in uyo, akwaibom state of nigeria.– new york science journal, 3/4, 117–22. ahmed, n., bodrud-doza, m., islam, a.r.m.t., hossain, s., moniruzzaman, m., deb, n. & bhuiyan, m.a.q. (2019): appraising spatial variations of as, fe, mn and no3 contaminations associated health risks of drinking water from surma basin, bangladesh.– chemosphere, 218, 726–740. http://doi.org/10.1016/j.chemosphere.2018.11.104 ali, w., mushtaq, n., javed, t., zhang, h., ali, k., rasool, a. & farooqi, a. (2019a): vertical mixing with return irrigation water the cause of arsenic enrichment in groundwater of district larkana sindh, pakistan.– environmental pollution, 245, 77–88. http://doi.org/10.1016/j. envpol.2018.10.103 ali, w., rasool, a., junaid, m. & zhang, h. (2019b): a comprehensive review on current status, mechanism, and possible sources of arsenic contamination in groundwater: a global perspective with prominence of pakistan scenario.– environmental geochemistry and health, 41/2, 737–760. http://doi.org/10.1007/s10653-018-0169-x alley, w.m., winter, t.c., harvey, j.w. & franke, o.l. (1998): ground water and surface water: a single resource.– us geological survey circular, 1139, 79. table 3. the results of add (mg/kg/day), hq and cancer risk assessment for groundwater samples. as add hq cr 20.42 5.67e-4 1.890 8.51e-4 11.46 3.18e-4 1.061 4.78e-4 6.529 1.81e-4 0.604 2.72e-4 15.28 4.24e-4 1.414 6.37e-4 13.14 3.65e-4 1.216 5.48e-4 12.45 3.46e-4 1.152 5.19e-4 18.63 5.18e-4 1.725 7.76e-4 17.58 4.88e-4 1.627 7.33e-4 18.76 5.21e-4 1.737 7.82e-4 18.25 5.07e-4 1.689 7.6e-4 10.55 2.93e-4 0.976 4.4e-4 11.28 3.13e-4 1.044 4.7e-4 4.702 1.31e-4 0.435 1.96e-4 2.722 7.56e-5 0.252 1.13e-4 18.32 5.09e-4 1.696 7.63e-4 8.162 2.27e-4 0.755 3.4e-4 21.98 6.11e-4 2.035 9.16e-4 26.64 7.4e-4 2.466 1.11e-3 18.31 5.09e-4 1.695 7.63e-4 53.75 1.493e-3 4.976 2.24e-3 10.13 2.81e-4 0.937 4.22e-4 13.84 3.84e-4 1.281 5.77e-4 2.83 7.86e-5 0.262 1.18e-4 5.41 1.5 e-4 0.500 2.25e-4 2.31 6.42e-5 0.213 9.63e-5 2.67 7.42e-5 0.247 1.11e-4 0.13 3.61e-6 0.012 5.42e-6 1.69 4.69e-5 0.156 7.04e-5 g eo lo gi a c ro at ic a 138 geologia croatica 78/2 ashraf, a., ahmad, z. & akhter, g. (2018): monitoring groundwater flow dynamics and vulnerability to climate change in chaj doab, indus basin, through modeling approach.– in: mukherjee, a. (ed.): groundwater of south asia.– springer, singapore, 593–611. brahman, k.d., kazi, t.g., afridi, h.i., naseem, s., arain, s.s. & ullah, n. (2013): evaluation of high levels of fluoride, arsenic species and other physicochemical parameters in underground water of two sub districts of tharparkar, pakistan: a multivariate study.– water research, 47/3, 1005–1020. http://doi.org/10.1016/j.watres.2012.10.042 çelebi, a., şengörür, b. & kløve, b. (2014): human health risk assessment of dissolved metals in groundwater and surface waters in the melen watershed, turkey.– journal of environmental science and health: part a, 49/2, 153–161. https://doi.org/10.1080/10934529.2013.838842 cardon, g.e., waskom, r.m., bauder, t.a. & davis, j.g. (2003): managing salts in agricultural waters.– colorado state university extension, fort collins, usa. eid, m.h., awad, m., mohamed, e.a., nassar, t., abukhadra, m.r., el-sherbeeny, a.m., kovács, a. & szűcs, p. (2024): comprehensive approach integrating water quality index and toxic element analysis for environmental and health risk assessment enhanced by simulation techniques.– environmental geochemistry and health, 46/10, 409. http://doi.org/10.1007/s10653-024-02182-1 gibbs, r.j. (1970): mechanisms controlling world water chemistry.– science, 170/3962, 1088-1090. http://doi.org/10.1126/science.170.3962.1088 greenman, d.w., bennett, g.d. & swarzenski, w.v. (1967): ground-water hydrology of the punjab, west pakistan, with emphasis on problems caused by canal irrigation.– geological survey water-supply paper, 1608-h, 1-66. hashmi, s. (2000): the need for water quality guidelines for pakistan.– medical forum monthly, 11/1, 6–16. iris (2011): integrated risk information system. environmental protection agency region i: washington, dc, usa, 20460. janjua, a.a., aslam, m., sultana, n. & batool, z. (2021): identification of climate induced optimal rice yield and vulnerable districts rankings of the punjab, pakistan.– scientific reports, 11/1, 1–15. http:// doi.org/10.1038/s41598-021-02691-4 kazmi, a.h. & jan, m.q. (1997): geology and tectonics of pakistan.– graphic publishers. kumar, p.s. (2013): interpretation of groundwater chemistry using piper and chadha’s diagrams: a comparative study from perambalur taluk.– elixir geosciences, 54, 12208–12211. letey, j., hoffman, g.j., hopmans, j.w., grattan, s.r., suarez, d., corwin, d.l., oster, j.d., wu, l. & amrhein, c. (2011): evaluation of soil salinity leaching requirement guidelines.– agricultural water management, 98/4, 502–506. http://doi.org/10.1016/j.agwat.2010. 08.009 li, p., karunanidhi, d., subramani, t. & srinivasamoorthy, k. (2021): sources and consequences of groundwater contaminations.– archives of environmental contamination and toxicology, 80, 1–10. http://doi.org/10.1007/s00244-020-00805-z lin, l., yang, h. & xu, x. (2022): effects of water pollution on human health and disease heterogeneity: a review.– frontiers in environmental science, 10, 880246. http://doi.org/10.3389/fenvs.2022.880246 macdonald, a.m., bonsor, h.c., ahmed, k.m., burgess, w.g., basharat, m., calow, r.c. & yadav, s.k. (2016): groundwater quality and depletion in the indo-gangetic basin mapped from in situ observations.– nature geoscience, 9/10, 762–766. http://doi.org/10.1038/ ngeo2791 marandi, a. & shand, p. (2018): groundwater chemistry and the gibbs diagram.– applied geochemistry, 97, 209–212. https://doi.org/10.1016/j. apgeochem.2018.07.009 marghade, d., malpe, d.b. & zade, a.b. (2011): geochemical characterization of groundwater from northeastern part of nagpur urban, central india.– environmental earth sciences, 62/7, 1419–1430. http://doi. org/10.1007/s12665-010-0627-y mazumder, d.g. (2008): chronic arsenic toxicity & human health.– indian journal of medical research, 128/4, 436–447. merino, l.m., aguilera, h., gonzález-jiménez, m. & díaz-losada, e. (2021): d-piper, a modified piper diagram to represent big sets of hydrochemical analyses.– environmental modelling & software, 138, 104979. http://doi.org/10.1016/j.envsoft.2021.104979 narany, t.s., ramli, m.f., aris, a.z., sulaiman, w.n.a., juahir, h. & fakharian, k. (2014): identification of the hydrogeochemical processes in groundwater using classic integrated geochemical methods and geostatistical techniques, in amol‐babol plain, iran.– the scientific world journal, 1, 419058. narsimha, a., sudarshan, v., srinivasulu, p., vishnu, b., kumar, m.r. & kumar, s.n. (2012): groundwater quality and its suitability for drinking and agricultural purpose around chityal area, nalgonda district, andhra pradesh, india.– water resources development, 2/3, 68–75. peeters, l. (2014): a background color scheme for piper plots to spatially visualize hydrochemical patterns.– groundwater, 52/1, 2–6. http://doi. org/10.1111/gwat.12118 piper, a.m. (1944): a graphic procedure in the geochemical interpretation of water‐analyses.– eos, transactions american geophysical union, 25/6, 914–928. https://doi.org/10.1029/tr025i006p00914 rabbani, u., mahar, g., siddique, a. & fatmi, z. (2017): risk assessment for arsenic-contaminated groundwater along river indus in pakistan.– environmental geochemistry and health, 39/1, 179–190. http://doi.org/10.1007/s10653-016-9818-0 rasool, a., xiao, t., farooqi, a., shafeeque, m., liu, y., kamran, m.a. & eqani, s.a.m.a.s. (2017): quality of tube well water intended for irrigation and human consumption with special emphasis on arsenic contamination at the area of punjab, pakistan.– environmental geochemistry and health, 39, 847–863. rehman, f., cheema, t., azeem, t., naseem, a.a., khan, i., iqbal, n., shaheen, a. & rehman, q.u. (2020): groundwater quality and potential health risks caused by arsenic (as) in bhakkar, pakistan.– environmental earth sciences, 79/24, 1–13. http://doi. org/10.1007/s12665-020-09270-2 sajil kumar, p.j. (2016): influence of water level fluctuation on groundwater solute content in a tropical south indian region: a geochemical modelling approach.– modeling earth systems and environment, 2(4), 1–9. sappa, g., ergul, s. & ferranti, f. (2014): geochemical modeling and multivariate statistical evaluation of trace elements in arsenic contaminated groundwater systems of viterbo area, (central italy).– springerplus, 3/1, 1–19. http://doi.org/10.1186/2193-1801-3-237 sarkar, d. & rupali, d. (2007): biogeochemistry of arsenic in contaminated soils of superfund sites. united states environmental protection agency. shahid, m., khalid, m., dumat, c., khalid, s., niazi, n.k., imran, m., bibi, i., ahmad, i., hammad, h.m. & tabassum, r.a. (2018): arsenic level and risk assessment of groundwater in vehari, punjab province, pakistan.– exposure and health, 10, 229–239. http:// doi.org/10.1007/s12403-017-0257-7 shaji, e., santosh, m., sarath, k.v., prakash, p., deepchand, v. & divya, b.v. (2021): arsenic contamination of groundwater: a global synopsis with focus on the indian peninsula.– geoscience frontiers, 12/3, 101079. http://doi.org/10.1016/j.gsf.2020.08.015 shakir, m.s., ahmed, m. & khan, m.a. (2002): irrigational quality of underground water in kasur district.– asian journal of plant sciences, 1/1, 1–15. http://doi.org/10.3923/ajps.2002.53.54 singh, a.k., mondal, g.c., kumar, s., singh, t.b., tewary, b.k. & sinha, a. (2008): major ion chemistry, weathering processes and water quality assessment in upper catchment of damodar river basin, india.– environmental geology, 54/4, 745–758. http://dx.doi.org/10.1007/ s00254-007-0860-1 skaggs, t.h., suarez, d.l., goldberg, s. & shouse, p.j. (2012): replicated lysimeter measurements of tracer transport in clayey soils: https://doi.org/10.1080/10934529.2013.838842 g eologia c roatica 139rehman et al.: integrated assessment of groundwater quality, agriculture suitability and health risk assessment in the upper indus basin ... effects of irrigation water salinity.– agricultural water management, 110, 84–93. https://doi.org/10.1016/j.agwat.2012.04.003 smedley, p.l. (2008): sources and distribution of arsenic in groundwater and aquifers.– in: arsenic in groundwater: a world problem.– utrecht, the netherlands, international association of hydrogeologists publication, 5 (iah), 4–32. sudhakar, a. & narsimha, a. (2013): suitability and assessment of groundwater for irrigation purpose: a case study of kushaiguda area, ranga reddy district, andhra pradesh, india.– advances in applied science research, 4/6, 75–81. tabassum, r.a., shahid, m., dumat, c., niazi, n.k., khalid, s., shah, n.s., imran, m. & khalid, s. (2019): health risk assessment of drinking arsenic-containing groundwater in hasilpur, pakistan: effect of sampling area, depth, and source.– environmental science and pollution research, 26/20, 20018–20029. https://doi.org/10.1007/s11356018-1276-z tadesse, n., bheemalingeswara, k. & berhane, a. (2009): groundwater suitability for irrigation: a case study from debre kidane watershed, eastern tigray, ethiopia.– momona ethiopian journal of science, 1/1, 36–58. http://doi.org/10.4314/mejs.v1i1.46040 talib, m.a., tang, z., shahab, a., siddique, j., faheem, m. & fatima, m. (2019): hydrogeochemical characterization and suitability assessment of groundwater: a case study in central sindh, pakistan.– international journal of environmental research and public health, 16/5, 886. http://doi.org/10.3390/ijerph16050886 ullah, z., rashid, a., ghani, j., talib, m.a., shahab, a. & lun, l. (2023): arsenic contamination, water toxicity, source apportionment, and potential health risk in groundwater of jhelum basin, punjab, pakistan.– biological trace element research, 201/1, 514–524. http://dx.doi. org/10.1007/s12011-022-03139-0 us-epa (2001): united states environmental protection agency. quality assurance guidance document-model quality assurance project plan for the pm ambient air, 2. us-epa (2005): guidelines for carcinogen risk assessment.– in risk assessment forum us environmental protection agency, washington, dc epa/630/p-03 f, 1, 1-20. wilcox, l.v. (1958): determining the quality of irrigation water.– agricultural information bulletin, 197, 10–30. zhang, z., xiao, c., adeyeye, o., yang, w. & liang, x. (2020): source and mobilization mechanism of iron, manganese and arsenic in groundwater of shuangliao city, northeast china.– water, 12/2, 534. https://doi.org/10.3390/w12020534 zubair, m., martyniuk, c.j. & shaheen, a. (2018): rising level of arsenic in water and fodder: a growing threat to livestock and human populations in pakistan.– toxin reviews, 37/3, 171–181. https://doi.org/ 10.1080/15569543.2017.1348360 who (2011): world health organization: guidelines for drinking-water quality.– world health organization, geneva, switzerland. who (2017): world health organization: guidelines for drinking-water quality: fourth edition incorporating the first addendum.– world health organization, geneva, switzerland. web sources: bauder, t.a., waskom, r.m., sutherland, p.l. & davis, j.g. (2011): irrigation water quality criteria. colorado state university. fact sheet 0.506. available at: https://extension.colostate.edu/docs/pubs/ crops/00506.pdf. accessed on: january 25th 2025. un-water (2021): summary progress update: sdg 6 – water and sanitation for all. available at: https://www.unwater.org/sites/default/files/app/ uploads/. accessed on: january 25th 2025. https://doi.org/10.1080/15569543.2017.1348360 https://doi.org/10.1080/15569543.2017.1348360 https://extension.colostate.edu/docs/pubs/crops/00506.pdf https://extension.colostate.edu/docs/pubs/crops/00506.pdf https://www.unwater.org/sites/default/files/app/uploads/ https://www.unwater.org/sites/default/files/app/uploads/ www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2024 | 77/2 | 145–158 | 6 figs. | 2 tabs. | 2 supplements | article history: manuscript recieved: april 18, 2024 revised manuscript accepted: may 27, 2024 available online: june 21, 2024 keywords: karst hydrogeology, major ions, isotopes, time series analysis, emerging organic contaminants, jadro and žrnovnica springs 1. introduction karst aquifers are intricate, highly dynamic and heterogeneous systems with enlarged fractures, an often well-developed conduit network, direct surface-subsurface connection via ponors, and high hydraulic conductivity, leading to preferential flow pathways and significant drinking water resources susceptible to anthropogenic contamination (padilla & vesper, 2018; živanović et al., 2022). interpreting hydrochemical spring responses and identifying the origins of chemical compounds in karst water, some of which as natural traces allow the understanding of system functioning and structure (perrin, 2003; mudarra et al., 2011; sheikhy narany et al., 2019), can help to pinpoint contamination sources and pathways (hillebrand et al., 2014). the hydrochemical research of the karst aquifer in question is fundamental in characterising the behaviour and origin of emerging organic contaminants (eocs). in 26 sampling campaigns within the jadro and žrnovnica dinaric karst catchment (croatia), water samples were collected for ion and stable isotope analysis. notably, in seven of these campaigns, samples were hydrochemical characterization of a dinaric karst catchment in relation to emerging organic contaminants ana selak1, jasmina lukač reberski1,*, maja briški1 and lorena selak2 1 croatian geological survey, department of hydrogeology and engineering geology, sachsova 2, 10000 zagreb, croatia; (*corresponding author: jlukac@hgi-cgs.hr) 2 aarhus university, department of biology, section for microbiology, ny munkegade 114, 8000 aarhus c, denmark doi: 10.4154/gc.2024.10 abstract the main findings of a hydrochemical investigation conducted within a typical dinaric karst catchment located in southern croatia are outlined. the studied aquifer is drained by the jadro and žrnovnica springs, which are important for the regional and local water supplies, respectively. presumably, there is intercatchment groundwater flow coming from the neighbouring cetina river catchment. various factors governing aquifer hydrochemistry and their interplay with emerging organic contaminants (eocs) that were detected at different water resources in ng/l concentrations was assessed. a total of 26 sampling campaigns (october 2019 – october 2022) were conducted at two springs, in a river and at a deep borehole, all representative of this complex hydrogeological system. assessment of major ion constituents and saturation indices calculated with phreeqc revealed the sampled water resources are of a ca-hco3 type due to the predominant weathering of the carbonate mineral calcite. sharp spikes observed in chemographs indicated a highly karstified system with an effective conduit network allowing rapid spring responses to precipitation events. water resources are of good chemical status, as affirmed by anthropogenic contamination indicators, with nitrates, chlorides and sulphates all below maximum threshold values. strong positive correlations were found between eocs concentration, number of detected compounds, and nitrates in the cetina river, indicating a common origin, most likely wastewater. identification of persistent eocs including widely used repellent n,n-diethyl-metatoluamide (deet) during base flow conditions and its strong positive correlation with the ca2+ content in both the cetina and jadro samples, suggests potential storage in the epikarst and aquifer matrix. this coupling of conventional hydrochemical indicators and novel markers of anthropogenic impacts, including eocs, in vulnerable karst water resources is a crucial advancement in the assessment and management of emerging environmental and potential human health risks. such an approach is pivotal for the sustainable protection of hydrogeologically intricate sites. specifically taken for eoc analysis. eocs are typically encountered in karst water resources at concentrations ranging from ng/l to µg/l, encompassing a myriad of anthropogenic organic compounds (lukač reberski et al., 2023). some eocs exert adverse effects on aquatic ecosystems and human health (cizmas et al., 2015; schriks et al., 2010). numerous uncertainties persist regarding the presence and behaviour of eocs within large hydrogeological domains (llamas et al., 2022). due to diverse physico-chemical properties and sources, coupled with the intricacy of dinaric karst structures and (ground)water pathways, datasets and analyses necessary to comprehend eocs behaviour can be extensive. multivariate statistical analyses have a broad application in simplifying large datasets, facilitating characterization of interrelationships among numerous hydrogeological variables, uncovering main hydrogeological processes, and providing insights into temporal and spatial variations (matiatos et al., 2014; jebreen et al., 2018). these invaluable analytical tools were employed in this study for the reliable interpretation of intricate karst dynamics and mailto:jlukac@hgi-cgs.hr g eo lo gi a c ro at ic a 146 geologia croatica 77/2 hydrochemical fluctuations (caetano bicalho, 2012; vasić et al., 2020; ćuk đurović et al., 2022). the hydrological and hydrogeological features of the jadro and žrnovnica aquifer have been extensively documented in prior studies by jukić & denić-jukić (2008), kapelj et al. (2012), bonacci & andrić (2015), kadić et al., (2019), and selak et al. (2024). additionally, the (eco)toxicological aspects related to eocs occurrence in this karst aquifer were previously explored by selak et al. (2022, 2024). this study seeks to enhance our understanding of karst aquifer behaviour under varying hydrological conditions by utilizing major ion and stable water isotopes data. the analysis of stable isotopes of oxygen δ18o and hydrogen δ2h has been effective in discerning groundwater provenance and karst aquifer recharge processes (clark & fritz, 1997). we posited that certain identified eocs could correlate with physico-chemical parameters of water resources within the studied system. these relationships may facilitate the identification of potential contamination sources, behaviour, and transport. we pursued the objective of elucidating factors that govern the hydrochemistry of the jadro and žrnovnica springs catchment. this involved monthly sampling at two aforementioned karst springs, a deep borehole, and the adjacent cetina river from which presumably groundwater inflows into the studied catchment (fritz, 1979; jukić & denić-jukić, 2015). 2. materials and methods 2.1. study area the immediate catchment of the jadro and žrnovnica springs in southern dalmatia (croatia) extends to an area of around 500 km2 of heterogeneous relief defined by interchanging mountains and karst poljes. both jadro (35 m a.s.l.) and žrnovnica (spring zone 78 to 90 m a.s.l.) emerge at the foot of mosor mountain where an impermeable coastal flysch belt meets with the permeable carbonate rocks of the hinterland (for detailed hydrogeological map readers are referred to selak et al., 2024). typical karst, well-expressed geomorphology has a predominant nw-se dinaric orientation. the catchment mainly consists of karstified carbonate rocks of mesozoic and partly eocene age, characterized by their high permeability, lack of soil cover and consequently absence of surface watercourses (kapelj et al., 2012). jadro with a mean discharge of 9.4 m3/s (data period 2011-2022) is used for the regional water supply of split and its wider area. žrnovnica with mean discharge of 1.7 m3/s (data period 2011-2022) supplies the nearby settlement and local agricultural areas. previous studies denote overlap of the springs’ catchments and groundwater exchange between them (jukić & denić-jukić, 2008; bonacci & roje-bonacci, 1997; bonacci & andrić, 2015; kadić et al., 2017). moreover, a tracer test undertaken at the grabov mlin ponor proved the presence of intercatchment groundwater flows coming from the adjacent cetina river catchment (fig. 1) (geotehnika, 1975; fritz, 1979), thereby expanding the overall catchment area. the diverse relief affects the local climate, with a prevalence of temperate humid köppen climate type cfa, while the mountainous areas of kozjak and mosor exhibit a temperate humid climate type cfb (šegota & filipčić, 2003). the mean daily air temperature, recorded at split marjan meteorological station at 122 m a.s.l. (data period 2009-2022), is 17.4°c. annual precipitation averages 1304 mm (data period 2009-2022) with non-uniform spatial distribution within the catchment. figure 1. location of the study area (world karst aquifer map by bgr et al. (2017)). g eologia c roatica 147selak et al.: hydrochemical characterization of a dinaric karst catchment in relation to emerging organic contaminants both springs respond rapidly (within 24 hours) to rainfall, indicating the presence of a substantial rapid flow component (kadić et al., 2019) primarily generated by rainfall from the dugopolje area (jukić et al., 2022). consequently, rapid alterations in spring hydrochemistry, accompanied by prompt arrival of potential anthropogenic inputs can be anticipated. 2.2. sampling and analysis of physico-chemical and hydrochemical parameters in 26 sampling campaigns between october 2019 and october 2022, physico-chemical parameters were measured in situ using a wtw multi-parameter probe at the jadro and žrnovnica springs, cetina river and gizdavac borehole. only jadro was monitored in march 2019. the covid-19 pandemic disrupted regular monthly surveys in 2019 and 2020. measurements and sampling were undertaken directly at the springs, while a bucket of water was collected from the midstream of the cetina river. before conducting sampling and measurements in the bucket, three volumes of groundwater were pumped from the borehole gizdavac to ensure a representative sample of the aquifer. during our research, among the three deep boreholes used for groundwater monitoring, only the gizdavac borehole featured a functional pump (installed at the depth of 266 metres). alkalinity was determined by volumetric titration using 1.6n h2so4 until reaching a ph 4.5, employing hach digital titrator model 16900 with bromocresol green-methyl red as an indicator. the water temperature and electrical conductivity data in the jadro and žrnovnica springs, as well as the cetina river (upstream of trilj city at vedrine hydrological station), were recorded using hobo data loggers u24 from onset computer corporation (bourne, ma, usa). the data was captured with hourly readings, commencing on 10th march 2021 for the jadro and žrnovnica springs, and on 11th march 2021 for the cetina river. a total of 84 water samples were collected, including 26 from each of the cetina river, jadro and žrnovnica springs, and an additional 6 samples from the gizdavac borehole. samples were collected in 200 ml and 100 ml polyethylene bottles for analysis of major anions, cations, and stable water isotopes. for conservation purposes, samples were transported to the laboratory at 4°c and were analysed within 48h at the hydrochemical laboratory of the croatian geological survey. principal ion composition was determined using ion chromatography on a dionex ics-6000 dp. water quality analyses were assessed for cation-anion balance by calculating the relative deviation from charge balance (δmeq = 100 x (σmeq+ − σmeq−)/(σmeq+ + σmeq−) < ±5%) (domenico & schwartz, 1990). stable water isotopes δ18o and δ2h were measured using isotope-ratio mass spectrometry with a picarro l2130i (santa clara, usa) employing cavity ring-down spectroscopy (crds) technology. isotope measurements were crosschecked against picarro’s standards, which are periodically verified against international atomic energy agency (iaea) standards: vienna standard mean ocean water 2 (vsmow2) and standard light antarctic precipitation 2 (slap2). measurement precision was ± 0.3 ‰ for δ18ο and ± 1 ‰ for δ2h. deuterium excess (d-excess), defined as d = δ2h 8 x δ18o (dansgaard, 1964), was used as an indicator of precipitation air mass origin and non-equilibrium conditions during evaporation. in order to take into account the infiltration of precipitation into the system, mean isotopic precipitation values were weighted with the amount of precipitation using the following equation (yurtsever & gat, 1981): d d w i n i i i p p = × ∑= ∑ 1 (1) where pi is the monthly precipitation amount (mm), δi is the isotopic composition (‰), and n is the number of months. the croatian meteorological and hydrological service provided discharge data for the jadro and žrnovnica springs for the period 2011-2022 and precipitation data for 2009-2022. groundwater temperature and electrical conductivity data from the gizdavac borehole logger (period 2010-2022) were provided by croatian waters. they also provided discharge data for the cetina river, measured at the trilj žičara station. a piper plot was used for classifying the predominant water types for the springs, groundwater, and surface water. this plot characterizes water based on major cation and anion content in meq/l, enabling analysis of the chemical composition for each water source (piper, 1944; appelo & postma, 2005). saturation indices (si) were calculated to determine the chemical equilibrium between minerals and groundwater using phreeqc v. 3.7.3.15968 (parkhurst & appelo, 1999; usgs, 2021). when si values are negative, minerals will be dissolved, since the water is undersaturated with respect to them. conversely, positive si values indicate oversaturation and mineral precipitation. 2.3. multivariate statistical analysis statistical analyses were performed in r (v. 1.4.1717; r core team, 2021) using packages stats (r core team, 2023), dunn.test (dinno, 2017), corrplot (wei & simko, 2021), vegan (oksanen et al., 2022), and hmisc (harell, 2023). the shapiro-wilk test was performed to investigate whether the hydrogeochemical data is normally distributed (p-value > 0.05). a nonparametric kruskal-wallis test with a post hoc dunn test with bonferroni correction (hollander & wolfe, 1973; ogle et al., 2023) was used to test for a statistically significant difference between the hydrochemical parameters from different sampling locations. to gain insights into the relationships between the hydrochemical parameters in each sample, a correlation matrix was performed using spearman’s rank correlation coefficient (spearman, 1904) on a normalized dataset. furthermore, the total sum of eocs and their detection rate (number of detected compounds per sampling location) were correlated with major cations and anions. 4. results and discussion 4.1. hydrochemical composition of the springs, river and groundwater temporal variability in water quality inherent to the karstic system of jadro and žrnovnica springs was comprehensively monitored for three years. this facilitated the inclusion of the g eo lo gi a c ro at ic a 148 geologia croatica 77/2 entire spectrum of hydrological conditions and detailed hydrochemical characterization of the dinaric karst aquifer during both dry and wet seasons. table 1 summarizes the descriptive statistics of eleven physico-chemical parameters (t, ph, ec, na+, k+, mg2+, ca2+, cl-, no3 -, so4 2-, and hco3 -) ascertained across 26 distinct sampling campaigns and different hydrological conditions. consistent with findings for sizable karst aquifers (pulido-bosch, 2021), water temperature in both the springs and groundwater exhibited limited variability over the observed period. as expected, the cetina river displayed a broader temperature range with pronounced daily oscillations due to direct contact with the atmosphere (table 1). all water constituents in the investigated catchment exhibited a slightly alkaline ph typical of carbonate aquifers (matić et al., 2012; patekar et al., 2022; maldini et al., 2023). given the relatively low anthropogenic interference in the studied catchment (loborec et al., 2015), we postulate that the electrical conductivity oscillations are predominantly governed by the dissolution of karst aquifer rocks. comparatively, groundwater exhibited somewhat higher mean ec values, ref lecting prolonged residence periods. the piper plot (fig. 2) revealed a ca-hco3 hydrogeo chemical facies present in all the examined samples. this facies is indicative of prevailing carbonate weathering processes, aligning with the characteristic hydrochemical profile of dinaric karst water resources, as substantiated in prior studies (matić et al., 2012; terzić et al., 2014; filipović et al., 2023; maldini et al., 2023). in contrast to ca2+, mg2+ exhibits relatively low abundance (table 1, fig. 1), suggesting the predominance of limestone deposits over dolomite. this observation aligns with the lithological analysis of the table 1. main statistical descriptors of the physico-chemical parameters and discharge (m3/s) observed within the study area. water temperature (°c) and electrical conductivity (ec, µs/cm) data encompass the period from october 2019 to october 2022 for the jadro, and žrnovnica springs, and the cetina river, and from 9.11.2010.-31.10.2022 for the gizdavac borehole. commencing in march 2021, logger data for both springs and the river were incorporated into the statistical analysis. ph data is given for the period from october 2019 to october 2022, while discharge data is from january 2011december 2022 for the jadro and žrnovnica springs and from january 2019 – december 2022 for the cetina river (trilj žičara hydrological station). major ion data (mg/l) is shown for the period october 2019 – october 2022. site statistics t ec ph q na+ k+ mg2+ ca2+ cl– no3 – so4 2– hco3 – ja dr o sp rin g min 12.47 259.62 7.25 3.73 2.38 0.15 2.21 70.71 3.69 1.50 3.17 204.50 max 13.99 433.24 8.02 56.62 21.44 0.95 8.03 79.50 40.89 4.32 22.70 274.50 mean 13.12 355.36 7.47 9.42 9.43 0.52 5.56 75.55 14.84 2.31 12.47 236.07 median 13.09 351.45 7.46 6.62 6.39 0.50 5.75 75.62 9.47 2.27 11.61 236.07 variance 0.18 1573.60 0.03 49.9 36.17 0.03 2.60 4.01 120.00 0.36 31.48 171.41 žr no vn ic a sp rin g min 12.32 263.50 7.35 0.27 2.96 0.22 1.49 66.52 4.10 0.88 2.87 192.76 max 13.38 399.84 8.52 17.00 20.47 1.97 6.77 73.10 39.31 3.89 15.99 256.20 mean 12.84 320.01 7.79 1.73 8.99 0.72 4.44 70.50 14.29 1.66 9.00 222.36 median 12.88 312.20 7.76 0.87 6.88 0.57 4.59 71.08 10.49 1.50 8.20 224.48 variance 0.08 1311.65 0.05 4.96 30.57 0.18 2.34 4.51 104.19 0.45 12.23 176.59 ce tin a ri ve r min 6.89 263.10 7.80 11.10 1.71 0.32 3.32 55.55 2.53 0.52 9.36 176.90 max 16.90 562.00 8.57 305.00 52.76 2.25 7.37 73.07 85.92 3.26 28.49 267.18 mean 11.98 362.64 8.25 86.76 20.02 0.83 5.26 65.13 30.11 1.24 15.99 202.40 median 11.85 334.10 8.29 70.90 12.06 0.80 5.15 64.93 18.80 1.05 14.43 198.86 variance 8.26 5359.92 0.03 2771.38 304.56 0.19 0.91 10.57 713.30 0.43 23.10 316.55 g iz da va c bo re ho le min 12.00 329.60 7.26 / 2.36 0.19 2.30 91.92 3.83 2.47 2.59 296.46 max 12.80 501.60 7.58 / 3.38 0.78 6.43 108.89 9.93 4.22 5.65 318.42 mean 12.44 399.82 7.38 / 2.89 0.61 5.43 97.96 5.59 3.02 3.73 306.73 median 12.40 396.17 7.36 / 2.94 0.68 6.24 96.39 4.98 2.72 3.54 307.44 variance 0.005 0.0003 0.01 / 0.20 0.05 2.64 40.79 5.07 0.42 1.06 65.85 figure 2. piper plot presentation of the hydrochemical composition of the springs, river, and groundwater samples within the study area. g eologia c roatica 149selak et al.: hydrochemical characterization of a dinaric karst catchment in relation to emerging organic contaminants gizdavac borehole, which identified limestone as the sole aquifer rock constituent in that area (kapelj et al., 2006). si values calculated using phreeqc (table s3) indicate that most water samples are oversaturated with respect to calcite (fig. 4). sicalcite values ranged between -0.02 and 1.2 in the springs, ranged from 0.2 to 0.5 in groundwater, and varied between 0.4 and 1 in the cetina river. according to white (1997), a sicalcite of -0.3 marks the kinetic threshold for slowdown in dissolution processes, while a sicalcite value of +0.5 indicates the onset of precipitation. in contrast to the jadro spring and groundwater samples, the cetina river exhibited oversaturation with respect to dolomite, while over half of the žrnovnica spring samples showed dolomite undersaturation. these carbonate minerals are the prominent constituents of the host rocks within the studied aquifer. accordingly, river and spring samples exhibited ca2+ prevalence for cations, with an abundance order generally observed as ca2+ > na+ > mg2+ > k+. groundwater samples demonstrated a distinctive abundance order of cations, with ca2+ being the most prevalent, followed by mg2+ > na+ > k+. in groundwater and springs, a robust positive correlation (0.69 and 0.67, respectively) between ca2+ and hco3 suggests their common origin from calcite dissolution. most water samples were enriched with ca2+ and mg2+ relative to hco3 (fig. 3a) which confirms how the dissolution of calcite and dolomite by carbonic acid is not the only source of alkaline earths. excess ca2+ and mg2+ charges must be balanced by other major anions through dissolution or ion exchange processes. figure 3b shows samples aligning with the 1:1 line, suggesting gypsum and anhydrite dissolution alongside calcite and dolomite dissolution. this observation is further supported by gypsum saturation indices averaging around -2.5 for the springs, -2.9 for groundwater, and -2.4 for the cetina river, along with anhydrite saturation indices averaging around -3 for the springs, -3.3 for groundwater, and -2.8 for the cetina river (table s3). according to fritz’s hydrogeological study (1979), gypsum and anhydrite are expected near the surface in the northern part of the catchment along a fault delineating contact with triassic deposits and subsequent strata, north of muć polje. the average [mg2+]/[ca2+] molar ratios observed in all water samples approximated 0.1, as expected in aquifers draining predominantly limestone rocks. such ratios imply dolomite dissolution and calcite precipitation processes (appelo & postma, 2005). we noted a conspicuous decline in [mg2+]/[ca2+] during the hydrograph peaks and higher values in the recession periods. the highest values occurred at the later stages of recessions, consistent with the prevailing interpretation of increased mean residence time of karst groundwater during recession periods. elevated [mg2+]/[ca2+] ratios can be indicative of matrix water or diffuse recharge through the epikarst, whereas lower [mg2+]/[ca2+] values observed in spring water are associated with conduit recharge (toran & reisch, 2013). the observed lower [mg2+]/[ca2+] values, distinct positive and negative fluctuations in chemographs (fig. 4), and rapid hydrodynamic responses corroborate a highly karstified system with effective conduit network that transmits infiltration to springs under high flow conditions and the absence or presence of only thin overlying layers that fail to dampen the springs’ response to rainfall events. mobile compounds including cland so4 2-, which tend to accumulate in soil solution due to elevated evapotranspiration processes during the summer months (goldscheider & drew, 2007), display a concentration peak with the first significant autumn rainfall events (fig. 4). the measured levels of cl-, so4 2and no3 at all sampling sites remained appreciably below the maximum allowed concentrations (250 mg/l, 250 mg/l, and 50 mg/l, respectively) specified in the drinking water directive (2020/2184). in contrast to the springs and groundwater, the cetina river displayed a greater degree of variability in chemical composition, particularly with respect to concentrations of cl-, na+, hco3 -, and k+ ions (table 1, fig. 4). the strongest positive correlation of r=0.99 was observed between na+ and cl figure 3. a) biplots of (ca2+ + mg2+) versus (hco3 −). b) (ca2+ + mg2+) versus (hco3 − + so4 2−). g eo lo gi a c ro at ic a 150 geologia croatica 77/2 ions for the jadro, žrnovnica, springs and the cetina river (fig. s1). kruskal-wallis post hoc dunn test revealed no statistically significant distinction in terms of clion content among the observed locations (except for cetina vs. gizdavac) (table s2). this lends support to the presence of intercatchment groundwater flow, whereby groundwater from the cetina catchment traverses towards the jadro and žrnovnica springs. elevated na+ and clconcentrations are usually anticipated within coastal aquifers affected by seawater intrusion or input of airborne salts (lukač reberski et al., 2020; planfigure 4. multivariate chemographs showing the temporal variation in major ion and saturation indices for calcite and dolomite observed at the jadro and žrnovnica springs, cetina river and in groundwater from the gizdavac borehole. total eocs concentration per location (bar graph) were reported in selak et al. (2022a). x on the x-axis marks the sampling campaign with no eocs detected above limits of detection. g eologia c roatica 151selak et al.: hydrochemical characterization of a dinaric karst catchment in relation to emerging organic contaminants tak et al., 2021; patekar et al., 2022; filipović et al., 2023). in our case, the impermeable eocene flysch coastal belt hinders adriatic sea intrusion into the land, as observed by fritz (1979). however, strong positive correlations between so4 2-, mg2+, na+, and clin all water samples, and between those ions and k+ in the jadro spring and cetina river may indicate sea spray influence (fig. s1). furthermore, the presence of chloride may stem from evaporite dissolution (schmidt et al., 2013) or anthropogenic sources including wastewater and fertilizers (dogden et al., 2017), warranting additional research for comprehensive elucidation. elevated nitrate concentrations are typically associated with agricultural practices, encompassing the application of synthetic fertilizers (e.g. n/p/k and ammonium sulphate), the utilization of manure in cultivated fields, and septic systems discharges (dogden et al., 2017). the mean no3 concentrations observed within the research area remained below the recorded average in croatian dinaric karst groundwater, which stands at approx. 5 mg/l (ondrasek et al., 2021). over the course of six sampling campaigns at the deep borehole site, groundwater exhibited no3 concentrations somewhat higher than those observed at other sampling locations, with mean values of 3.02 mg/l compared to 2.31 mg/l for the jadro, and 1.66 mg/l for the žrnovnica springs, and 1.24 mg/l for the cetina river (table 1, fig. 4). loborec et al. (2015) observed the trajectory of increasing nitrate concentrations in the jadro spring over nearly four decades (1975-2014), substantiating the growing anthropogenic pressures exerted upon the catchment area. the presence of nitrates in groundwater may suggest rapid infiltration processes (celle-jeanton et al., 2003), which is also indicated by the occurrence of biodegradable eocs gabapentin identified in groundwater from the gizdavac borehole (selak et al., 2024). no3 displayed a strong positive correlation with so4 2in the žrnovnica spring (r=0.77) and groundwater from the gizdavac well (r=0.81) (fig. s1), as well as with k+ in groundwater (r=0.75). these ions could have similar anthropogenic sources in fertilizers and wastewater (han et al., 2016; mass et al., 2019; torres-martínez et al., 2020). as previously mentioned so4 2may originate from the dissolution of gypsum deposits north of muć, highlighting the intricate interplay between inherent hydrogeological processes and potential site-specific pollution sources. given the absence of concurrent stable nitrogen isotope analysis alongside nitrate measurement, a definite attribution of nitrate concentrations in groundwater to wastewater or agriculture pollution sources cannot be conclusively established. the strategically situated borehole along the regional muć-gizdavac-klis fault, delineates a prevailing groundwater flow direction from the nw to the se towards the jadro and žrnovnica springs (identified through a tracer test from the jablan ponor with high apparent groundwater flow velocities of 10.58 cm/s and 12.18 cm/s, respectively) (fritz, 1979). according to this, there is the potential conveyance of agricultural pollutants including fertilizers and pesticides from muć polje towards the sampled groundwater and spring locations within a relatively short time. it should be noted how recent research questions the reliability of the tracer tests conducted, as the electrical conductivity of the jadro spring does not display the rainfall effect from muć despite the highest apparent groundwater velocity (jukić et al., 2022). further investigation is necessary to deepen our understanding of the sources and pathways of anthropogenic contaminants within the studied catchment. 4.2. stable water isotopes table 2 provides a descriptive statistical overview of the stable water isotopes δ18ο and δ2h, including deuterium excess, for springs, river, groundwater, and precipitation. cetina river δ18ο data deviated from a normal distribution (table s1). the results for the jadro and žrnovnica springs corroborates earlier research by kapelj (2001; published in brkić et al., 2020) and poljak (2014), aligning with the average stable water isotopic values observed in dalmatian karst springs, which typically vary between -6.7‰ and -8.7‰ for δ18ο and -39.7‰ and -58‰ for δ2h (brkić et al., 2020). the isotopic content of precipitation is slightly depleted compared to the data presented by hunjak et al. (2013) for the split station, (located outside of catchment), that had an average of -5.5‰ for δ18o, -34.7‰ for δ2h and d-excess of 9.2 (for period 20072010). this is to be expected as our rain gauges were positioned in the hinterland and at higher altitudes than the split station (located near the coast at 40 m a.s.l.; fig. 1). the average d-excess values of karst groundwater, (springs and borehole) and surface water, correspond to the d-excess values of west mediterranean precipitation (gat & carmi, 1970; cellejeanton et al., 2001). precipitation at the dugopolje rain table 2. elementary statistics of isotopic signatures for all sampling points (data period october 2019 – october 2022 for springs, river, and groundwater, and data period march 2021 – october 2022 for precipitation). sampling location altitude (m.a.s.l.) δ18o (‰) δ2h (‰) d-excess (‰) min max mean sd min max mean sd mean jadro 35 –7.82 –7.05 –7.47 0.17 –47.31 –41.44 –44.76 1.43 15 žrnovnica 90 –8.05 –7.09 –7.56 0.22 –47.58 –40.79 –44.97 1.94 15.53 cetina ~294 –8.46 –7.20 –8.13 0.3 –52.93 –44.06 –50.1 2.02 14.96 gizdavac ~356 –7.09 –6.66 –6.94 0.17 –41.85 –39.31 –40.89 0.96 14.62 rain gauge dugopolje* 497 –9.09 –1.59 –6.42*** 1.94 –58.45 –6.33 –39.72*** 14.16 11.66*** rain gauge mosor** 869 –10.25 –3.43 –7.45*** 1.85 –62.53 –13.69 –43.33*** 13.47 16.28*** due to insufficient rain amounts collected in the rain gauge, the following data is missing: *no data for july 2021 and 2022; **no data from july to november 2021, and for july 2022. *** amount-weighted mean values. g eo lo gi a c ro at ic a 152 geologia croatica 77/2 gauge displayed a weighted-mean d-excess of 11.66‰, which is close to the global mean d-excess of 10‰ associated with atlantic air masses, but indicates a slight mediterranean influence. the mosor rain gauge recorded predominantly higher weighted-mean d-excess values (16.28‰), signifying a stronger mediterranean influence, but also the altitude effect (the rain gauge is located at 869 m a.s.l. in a mountainous area). water isotopic content is affected by meteoric processes and orographic effects (brkić et al., 2020). kapelj et al. (2012) determined an altitude gradient variation in δ18o, ranging from -0.2‰ to -0.4‰/100 m. slightly more negative δ18o and δ2h values for žrnovnica than jadro can be attributed to the altitude effect, i.e. recharge with precipitation from higher altitudes. the cetina river had an even lower average δ18o and δ2h values, which is attributed to a recharge area of higher altitudes and a stronger continental influence. in june 2021, there were notable similarities in the stable isotopic composition, particularly for δ18o and clcontent (fig. 4), between both springs and the cetina river. this observation hints at intercatchment groundwater flow coming from the cetina river to the jadro and žrnovnica springs. such inflows from the adjacent cetina river catchment were identified by jukić & denić-jukić (2015) in the partial auto-correlation function of the discharge signal. this phenomenon is likely more pronounced during dry periods, as indicated by the increase in the minimum flow rates at both springs (kadić et al., 2017). 4.3. correlation between hydrochemical parameters and emerging organic contaminants exploring relationships between emerging organic contaminants and other chemical indicators helps to understand the sources, occurrence, and transport of emerging contaminants in karst aquifers (katz & griffin, 2008; hillebrand et al., 2014; zemann et al., 2015). owing to a limited quantity of samples, the correlation between the hydrochemical parameters and concentrations of a particular eoc was solely feasible for the cetina river. readers are referred to the work by selak et al. (2022b) for a comprehensive inventory of analysed and identified eocs along with their limits of detection and physico-chemical properties. a very mobile pharmaceutical compound metformin (c4h11n5) was the only eoc detected more than twice at a single location (recorded in 4 out of 7 campaigns). metformin exhibited a statistically significant and strong positive correlation with ca2+ and no3 ions in the cetina river, with correlation coefficients of r=0.72 and r=0.89, respectively (fig. 5). additionally, a strong positive correlation (r=0.87) was observed between the total concentration of eocs and no3 ion in samples collected from the cetina river (fig. 6). nitrates, often indicative of anthropogenic contamination from wastewater or agriculture, were previously associated with particular eocs, including herbicides (hillebrand et al., 2014), x-ray contrast media (zemann et al., 2015), and carbamazepine (doummar et al., 2014). nitrates showed a positive correlation with increasing eocs detection number (zemann et al., 2015; richards et al., 2023) and total eoc sum (schaider et al., 2014). similar to findings of zemann et al. (2015) and richards et al. (2023), this research identified a statistically significant correlation (r=0.90) between the eocs number and no3 concentrations in the cetina river (fig. 6). these positive correlations validate the eocs sources map and conceptual model presented by selak et al. (2024). in groundwater samples, eocs detection number and total concentration were strongly negatively correlated with hco3 and ca2+ ions, while a strong positive correlation was observed between the eocs detection number, the total concentration and mg2+ ion (fig. 6). the prevalence of calcium and bicarbonate ions in groundwater, attributed to the predominance of limestone in the aquifer rocks, suggests that in this tectonically disturbed and highly permeable part of the aquifer with low matrix porosity typical of dinaric karst aquifers, the detected eocs undergo swift infiltration. this explains the presence of rapidly biodegradable gabapentin in the sample extracted from the gizdavac borehole. in the cetina river, we observed strong negative correlations (in descending order of correlation coefficient strength) between the number of eocs detections, the total concentration sum of eocs, and so4 2-, cl-, and na+, as well as between eocs detection rate and mg2+ and k+ ions, as depicted in fig. 6. similar patterns were noted in jadro samples, where the total eocs concentration and detection number displayed strong negative correlations with k+, na+, cl-, so4 2-, and mg2+ (fig. 6). moreover, žrnovnica spring samples exhibited strong negative correlations between eocs detection rate and mg2+, na+, cl-, so4 2-, and k+ ions. since cl-, na+, k+, so4 2-, and mg2+ ions can partly originate from sea spray, the negative correlation discerned with the eocs number and total concentration may suggest the absence of atmospheric input of eocs in the study figure 5. correlation matrix of hydrochemical parameters for cetina (correlation coefficients order with aoe algorithm the angular order of the eigenvectors) and eoc metformin. values marked with x are not significant. g eologia c roatica 153selak et al.: hydrochemical characterization of a dinaric karst catchment in relation to emerging organic contaminants area. conversely, a strong positive correlation was observed between the eocs detection number and total concentration sum with respect to ca2+ content in the cetina river and eocs detection number and ca2+ in the jadro spring samples. hillebrand et al. (2014) established a robust correlation between calcium ions and the herbicide atrazine, which they attributed to the gradual release of atrazine from the karst rock matrix into the groundwater. persistent and mobile compounds including deet detected in the cetina river and jadro spring, showed limited attenuation within the studied karst aquifer (selak et al., 2024). this compound showed elevated concentrations during autumn runoff and persisted even during base flow conditions, suggesting potential storage within the epikarst and matrix. 5. conclusions this hydrochemical characterization study has provided a comprehensive examination of the jadro and žrnovnica karst aquifer in both spatial and temporal dimensions, while analyzing factors influencing the quality of its water resources. the hydrochemical fingerprint of this aquifer is typical for coastal dinaric aquifers characterised by highly karstified structures, a prevalence of limestone, as indicated by the cahco3 hydrogeochemical facies, and clear evidence of seaspray influence. stable isotope signatures confirmed a common catchment area shared by the jadro and žrnovnica springs while also revealing intercatchment groundwater f low originating from the cetina river. figure 6. correlation matrix of hydrochemical parameters for the jadro (a), žrnovnica (b), gizdavac (c), and cetina (d) (correlation coefficients order with aoe algorithm the angular order of the eigenvectors), eocs detection number and total concentration sum. values marked with x are not significant. g eo lo gi a c ro at ic a 154 geologia croatica 77/2 alongside the hydrodynamics, hydrochemical characte­ rization has a pivotal role in comprehending the complexity of karst systems and assessing their susceptibility to eocs. sharp spikes in chemographs, alongside rapid hydrodynamic responses are evidence of a highly karstified and inherently vulnerable system. its well­developed conduit network can swiftly transport eocs via infiltrated water to springs under high flow conditions, as the absence of or thin overlying “protective” layers fail in their attenuation. while conventional indicators of anthropogenic pollution including no3 ­, cl­, and so4 2­ remain below their respective maximum allowable concentrations in drinking water, detections of eocs reflect the anthropogenic impact on water resources within the studied catchment. significant strong positive correlation between metformin and no3 ­ concentration in the cetina river, as well as significant strong positive correlation between total eocs concentration, number and no3 ­ ion, indicates potential contamination stemming from wastewater or agriculture. robust significant positive correlation between eocs detection rate and ca2+ content observed in the jadro spring samples suggests the persistence of certain eocs including deet within the epikarst and aquifer matrix. to enhance the reliability of multivariate analyses of hydrochemical parameters and eocs, we recommend that future research should involve a larger sample number and focus on monitoring prioritized eocs. in the context of this dinaric karst catchment, we propose directing research efforts towards persistent and mobile eocs, for example; deet, 1­h benzotriazole, and metformin. the future long­term monitoring and concurrent utilization of hydrochemical markers and novel tracers including eocs will offer enhanced clarity in discerning the intricate interplay of dominant factors shaping hydrochemical patterns within karst aquifers subject to various anthropogenic pressures. acknowledgement the authors express their gratitude to the croatian meteorological and hydrological service and croatian waters for the provided data. this work was financially supported by interreg central europe boderec­ce project co­funded by the european regional development fund, geotwinn project funded under h2020­eu.4.b., [grant number 809943] and nona project funded by national recovery and resilience plan 2021–2026 of the european union – nextgenerationeu, and monitored by the ministry of science and education of the republic of croatia. the field investigations and eocs analysis were funded and supported by the croatian geological survey, department of hydrogeology and engineering geology. references appelo, c.a.j., & postma, d. (2005): geochemistry, groundwater and pollution.– 2nd ed., a.a. balkema publishers, 672 p. bonacci, o., & andrić, i. (2015): karst spring catchment: an example from dinaric karst.– environ earth sci, 74/7, 6211–6223. doi: 10.1007/ s12665­015­4644­8 bonacci, o. & roje-bonacci, t. (1997): hidrološki vid određivanja bi­ ološkog minimuma rijeke žrnovnice. [hydrological aspects of determining the biological minimum of the žrnovnica river – in croatian].– hrvat vode, 5, 1997, 339–349. bgr, iah, kit, unesco (2017): world karst aquifer map, 1:40 000 000. berlin, reading, karlsruhe and paris. url: https://gdk.gdi-de.org/geo­ network/srv/api/records/473d851c­4694­4050­a37f­e421170eca8. brkić, ž., kuhta, m., hunjak, t., & larva, o. (2020): regional iso­ topic signatures of groundwater in croatia.– water, 12/7. doi: 10.3390/ w12071983 caetano bicalho, c., batiot­guilhe, c., seidel, j.l., van exter, s. & jourde, h. (2012): geochemical evidence of water so­ urce characterization and hydrodynamic responses in a karst aquifer.– j hydrol, 450–451, 206–218. doi: 10.1016/j.jhydrol.2012.04.059 celle­jeanton, h., emblanch, c., mudry, j. & charmoille, a. (2003): contribution of time tracers (mg2+, toc, δ13ctdic, no3 −) to understand the role of the unsaturated zone: a case study – karst aqu­ ifers in the doubs valley, eastern france.– geophys res lett, 30/6. doi: 10.1029/2002gl016781 celle­jeanton, h., travi, y. & blavoux, b. (2001): isotopic typo­ logy of the precipitation in the western mediterranean region at three different time scales.– geophys res lett, 28/7, 1215–1218. doi: 10.1029/2000gl012407 cizmas, l., sharma, v.k., gray, c.m. & mcdonald, t.j. (2015): pharmaceuticals and personal care products in waters: occurrence, toxi­ city, and risk.– environ chem lett, 13/4, 381–394. doi: 10.1007/s10311­ 015­0524­4 clark, i., & fritz, p. (1997): environmental isotopes in hydrology.– lewis publication. ćuk đurović, m., petrič, m., jemcov, i., mulec, j., grudnik, z. m., mayaud, c., blatnik, m., kogovšek, b. & ravbar, n. (2022): multivariate statistical analysis of hydrochemical and micro­ biological natural tracers as a tool for understanding karst hydrodyna­ mics (the unica springs, sw slovenia).– water resour res, 58/11, e2021wr031831. doi: 10.1029/2021wr031831 dansgaard, w. (1964): stable isotopes in precipitation.– tellus, 16/4, 436–468. doi: 10.1111/j.2153­3490.1964.tb00181.x dinno, a. (2017): dunn.test: dunn’s test of multiple comparisons using rank sums. https://cran.r­project.org/package=dunn.test directive (eu) 2020/2184 of the european parliament and of the council of 16 december 2020 on the quality of water intended for human con­ sumption. dodgen, l.k., kelly, w.r., panno, s.v, taylor, s.j., armstrong, d.l., wiles, k.n., zhang, y. & zheng, w. (2017): characterizing pharmaceutical, personal care product, and hormone contamination in a karst aquifer of southwestern illinois, usa, using water quality and stream flow parameters.– sci total environ, 578, 281–289. doi: 10.1016/j. scitotenv.2016.10.103 domenico, p.a. & schwartz, f.w.(1990). physical and chemical hy­ drogeology. john wiley and sons, new york, 824 p. doummar, j., geyer, t., baierl, m., nödler, k., licha, t. & sa­ uter, m. (2014): carbamazepine breakthrough as indicator for specific vulnerability of karst springs: application on the jeita spring, lebanon.– appl geochemistry, 47, 150–156. doi: 10.1016/j.apgeochem.2014.06.004 filipović, m., frangen, t., terzić, j. & lukač reberski, j. (2023): hydrogeology of a complex karst catchment in southern dalma­ tia (croatia) and western herzegovina (bosnia and herzegovina).– j maps, 19/1, 2112775. doi: 10.1080/17445647.2022.2112775 fritz, f. (1979): općina split. hidrogeološka studija. [split municipality. hydrogeological study – in croatian].– hrvatski geološki institut. fond stručne dokumentacije, 191. gat, j.r. & carmi, i. (1970): evolution of the isotopic composition of atmospheric waters in the mediterranean sea area.– j geophys res, 75/15, 3039–3048. doi: 10.1029/jc075i015p03039 geotehnika (1975): akumulacija đale – pribransko rješenje. istraživač­ ko projektna dokumentacija. idejni projekt za brtvljenje akumulacijskog bazena [đale reservoir – dam design. research project documentation. conceptual design for sealing the accumulation basin. – in croatian].– fond struč. dok. elektroprivrede dalmacije, split. g eologia c roatica 155selak et al.: hydrochemical characterization of a dinaric karst catchment in relation to emerging organic contaminants goldscheider, n. & drew, d. (2007): methods in karst hydrogeo­ logy.– iah: international contributions to hydrogeology, 26 (1st ed.). crc press, 260 p. doi: 10.1201/9781482266023 han, d., song, x., & currell, m.j. (2016): identification of anthropo­ genic and natural inputs of sulfate into a karstic coastal groundwater system in northeast china: evidence from major ions, δ13cdic and δ34sso4.– hydrol earth syst sci, 20/5, 1983–1999. doi: 10.5194/he­ ss­20­1983­2016 harrell, jr. f. (2023): hmisc: harrell miscellaneous. r package version 5.1­0, https://cran.r­project.org/package=hmisc. hillebrand, o., nödler, k., geyer, t., & licha, t. (2014): investi­ gating the dynamics of two herbicides at a karst spring in germany: consequences for sustainable raw water management.– sci total envi­ ron, 482–483, 193–200. doi: 10.1016/j.scitotenv.2014.02.117 hollander, m. & wolfe, d.a. (1973): nonparametric statistical methods.– john wiley, new york, new york. hunjak, t., lutz, h.o. & roller-lutz, z. (2013): stable isotope com­ position of the meteoric precipitation in croatia.– isotopes environ he­ alth stud, 49/3, 336–345. doi: 10.1080/10256016.2013.816697 jebreen, h., banning, a., wohnlich, s., niedermayr, a., gha­ nem, m. & wisotzky, f. (2018): the influence of karst aquifer mi­ neralogy and geochemistry on groundwater characteristics: west bank, palestine.– water, 10/12. doi: 10.3390/w10121829 jukić, d. & denić-jukić, v. (2008): estimating parameters of groundwater recharge model in frequency domain: karst springs jadro and žrnovnica.– hydrol process, 22/23, 4532–4542. doi: 10.1002/hyp.7057 jukić, d. & denić-jukić, v. (2015): investigating relationships between rainfall and karst­spring discharge by higher­order partial correlation functions.– j hydrol, 530, 24–36. doi: 10.1016/j.jhydrol.2015.09.045 jukić, d., denić-jukić, v. & kadić, a. (2022): temporal and spatial characterization of sediment transport through a karst aquifer by means of time series analysis.– j hydrol, 609. doi: 10.1016/j.jhydrol.2022.127753 kadić, a., denić-jukić, v. & jukić, d. (2017): revealing hydrological relations of adjacent karst springs by partial correlation analysis.– hydrol res, 49/3, 616–633. doi: 10.2166/nh.2017.064 kadić, a., denić-jukić, v. & jukić, d. (2019): analiza meteoroloških i hidroloških odnosa u kršu primjenom parcijalne kros­korelacijske funk­ cije višeg reda. [analysis of meteorological and hydrological relations in the karst using higher-order partial cross-correlation function – in croatian].– hrvatske vode, 27/109, 201­210. kapelj, s., kapelj, j., biondić, r., biondić, b., kovač, i., tušar, b., prelogović, e., marjanac, t., andrić, m., kovačić, d., strelec, s. & gazdek, m. (2006): studija upravljanja vodama sliva jadra i žrnovnice – prva faza studijsko istraživačkih radova [water management study of the jadro and žrnovnica springs recharge area – first phase – in croatian]. evv:1/2005.– hrvatske vode, split kapelj, s., kapelj, j., novosel, a. & singer, d. (2001): hidrogeo­ loška istraživanja slivnog područja izvora jadra i žrnovnice prelimi­ narni izvještaj, i faza istraživanja [hydrogeological study of the jadro and žrnovnica catchment area – preliminary report, first phase – in croatian]. fond str. dok. hgi, br. 42/01, zagreb. kapelj, s., kapelj, j. & švonja, m. (2012): hidrogeološka obilježja sliva jadra i žrnovnice [hydrogeological characteristics of the jadro and žrnovica catchement – in croatian].– tusculum, 5/1, 205–216. katz, b.g. & griffin, d.w. (2008): using chemical and microbiological indicators to track the impacts from the land application of treated mu­ nicipal wastewater and other sources on groundwater quality in a karstic springs basin.– environ geol, 55/4, 801–821. doi: 10.1007/s00254­007­ 1033­y llamas, m.i., jiménez­gavilán, p., luque­espinar, j.a., bena­ vente­herrera, j., candela, l., sanmiguel­martí, m., rambla­nebot, j., aranda­mares, j.l., & vadillo­pérez, i. (2022): hydrogeological, hydrodynamic and anthropogenic factors affecting the spread of pharmaceuticals and pesticides in water resources of the granada plain (spain).– j hydrol, 610, 127791. doi: 10.1016/j.jhy­ drol.2022.127791 loborec, j., kapelj, s. & novak, h. (2015): analysis of groundwater pollution hazard in karst: a case study of jadro and žrnovnica catchment area.– građevinar, 67/11, 1093–1103. doi: 10.14256/jce.1250.2015 lukač reberski, j., rubinić, j., terzić, j. & radišić, m. (2020): climate change impacts on groundwater resources in the coastal kar­ stic adriatic area: a case study from the dinaric karst.– nat resour res, 29/3, 1975–1988. doi: 10.1007/s11053­019­09558­6 lukač reberski, j., selak, a., lapworth, d. j., maurice, l. d., terzić, j., civil, w. & stroj, a. (2023): emerging organic conta­ minants in springs of the highly karstified dinaric region.– j hydrol, 621, 129583. doi: 10.1016/j.jhydrol.2023.129583 maldini, k., cukrov, n., pikelj, k., matić, n. & mlakar, m. (2023): geochemistry of metals and organic matter in water and sedi­ ments of the karst river cetina, croatia.– water, 15/7. doi: 10.3390/ w15071429 maas, b., peterson, e.w., honings, j., oberhelman, a., owa­ re, p., rusthoven, i. & watson, a. (2019): differentiation of sur­ face water and groundwater in a karst system using anthropogenic signatures.– geosciences, 9/4. doi: 10.3390/geosciences9040148 matiatos, i., alexopoulos, a. & godelitsas, a. (2014): multiva­ riate statistical analysis of the hydrogeochemical and isotopic composi­ tion of the groundwater resources in northeastern peloponnesus ( greece).– sci total environ, 476/477, 577–590. doi: 10.1016/j.scito­ tenv.2014.01.042 matić, n., maldini, k., cuculić, v. & frančišković-bilinski, s. (2012): investigations of karstic springs of the biokovo mt from the dinaric karst of croatia.– geochemistry, 72/2, 179–190. doi: 10.1016/j. chemer.2011.08.001 mudarra, m., andreo, b. & baker, a. (2011): characterisation of dissolved organic matter in karst spring waters using intrinsic fluores­ cence: relationship with infiltration processes.– sci total environ, 409/18, 3448–3462. doi: 10.1016/j.scitotenv.2011.05.026 ogle, d.h., doll, j.c., wheeler, a.p., dinno, a. (2023): fsa: simple fisheries stock assessment methods. r package version 0.9.5, https:// cran.r­project.org/package=fsa. oksanen, j., simpson, g., blanchet, f. g., kindt, r., legendre, p., minchin, p., hara, r., solymos, p., stevens, h., szöcs, e., wagner, h., barbour, m., bedward, m., bolker, b., borcard, d., carvalho, g., chirico, m., de cáceres, m., durand, s. & weedon, j. (2022): vegan community ecology pac­ kage version 2.6­2 april 2022. ondrasek, g., bakić begić, h., romić, d., brkić, ž., husnjak, s. & bubalo kovačić, m. (2021): a novel lumnaqsop approach for prioritising groundwater monitoring stations for implementation of the nitrates directive.– environ sci eur, 33/1, 23. doi: 10.1186/s12302­ 021­00467­1 padilla, i.y. & vesper, d.j. (2018): fate, transport, and exposure of emerging and legacy contaminants in karst systems: state of knowled­ ge and uncertainty bt.– in: white, w.b., herman, j.s., herman, e.k. & rutigliano, m. (eds.): karst groundwater contamination and public health. springer international publishing, 33–49. parkhurst, d.l. & appelo, c.a.j. (1999): user’s guide to phreeqc (version 2)—a computer program for speciation, batch­reaction, one­dimensional transport, and inverse geochemical calculations. – u.s. geological survey, water resources investigations report, 99­4259, washington dc. patekar, m., bašić, m., pola, m., kosović, i., terzić, j., lucca, a., mittempergher, s., berio, l. r. & borović, s. (2022): mul­ tidisciplinary investigations of a karst reservoir for managed aquifer re­ charge applications on the island of vis (croatia).– acque sotter – ital j groundw, 11/1 37–48. doi: 10.7343/as­2022­557 perrin, j. (2003): a conceptual model of flow and transport in a karst aqu­ ifer based on spatial and temporal variations of natural tracers. piper, m.a. (1944): a graphic procedure in the geochemical interpretation of water­analyses.– eos, trans am geophys union, 25/6, 914–928. doi: 10.1029/tr025i006p00914 g eo lo gi a c ro at ic a 156 geologia croatica 77/2 plantak, l., biondić, r., meaški, h. & težak, d. (2021): hydroc­ hemical indicators analysis of seawater intrusion in coastal karstic aquifers on the example of the bokanjac-poličnik catchment area in zadar, croatia.– applied sciences, 11/24. doi: 10.3390/app112411681 poljak, (2014): određivanje srednjeg vremena zadržavanja podzemne vode u kršu primjenom prirodnih izotopa primjer sliva jadro i žrnovnica. [determination of mean residence time of groundwater in karst using natural isotopes – example of jadro and žrnovnica catchment – in croatian].– phd thesis, university of zagreb, faculty of geotechnical engineering. varaždin. pulido-bosch, a. (2021): principles of karst hydrogeology.– springer international publishing. doi: 10.1007/978­3­030­55370­8 r core team (2023): r: a language and environment for statistical com­ puting.– foundation for statistical computing, vienna, austria, https:// www.r­project.org richards, l.a., guo, s., lapworth, d.j., white, d., civil, w., wilson, g.j.l., lu, c., kumar, a., ghosh, a., khamis, k., krause, s., polya, d.a. & gooddy, d.c. (2023): emerging organic contaminants in the river ganga and key tributaries in the middle gangetic plain, india: characterization, distribution & controls. ­environ pollut, 327, 121626. doi: 10.1016/j.envpol.2023.121626 schaider, l.a., rudel, r.a., ackerman, j.m., dunagan, s.c., & brody, j.g. (2014): pharmaceuticals, perfluorosurfactants, and other organic wastewater compounds in public drinking water wells in a shallow sand and gravel aquifer.– sci total environ, 468–469, 384–393. doi: 10.1016/j.scitotenv.2013.08.067 schmidt, s., geyer, t., marei, a., guttman, j. & sauter, m. (2013): quantification of long-term wastewater impacts on karst groun­ dwater resources in a semi­arid environment by chloride mass balance methods.– j hydrol, 502, 177–190. doi: 10.1016/j.jhydrol.2013.08.009 schriks, m., heringa, m.b., van der kooi, m.m.e., de voogt, p. & van wezel, a.p. (2010): toxicological relevance of emerging contaminants for drinking water quality.– water res, 44/2, 461–476. doi: 10.1016/j.watres.2009.08.023 selak, a., lukač reberski, j., boljat, i. & terzić, j. (2024): cha­ racterizing occurrence of emerging organic contaminants in dinaric karst catchment of jadro and žrnovnica springs, croatia.– emerg contam, 10/3, 100327. doi: 10.1016/j.emcon.2024.100327 selak, a., lukač reberski, j., klobučar, g. & grčić, i. (2022a): ecotoxicological aspects related to the occurrence of emerging conta­ minants in the dinaric karst aquifer of jadro and žrnovnica springs.– sci. total environ., 825, 153827. doi:10.1016/j.scitotenv.2022.153827 selak, a., lukač reberski, j., klobučar, g. & grčić, i. (2022b): data on occurrence and ecotoxicological risk of emerging contaminants in dinaric karst catchment of jadro and žrnovnica springs.– data br., 42, 108157. doi:10.1016/j.dib.2022.108157 sheikhy narany, t., bittner, d., disse, m. & chiogna, g. (2019): spatial and temporal variability in hydrochemistry of a small­scale do­ lomite karst environment.– environ earth sci, 78/9, 273. doi: 10.1007/ s12665­019­8276­2 spearman, c. (1904): the proof and measurement of association between two things.– am. j. psychol. 15, 72–101. šegota, t., & filipčić, a. (2003): köppen’s classification of climates and the problem of corresponding croatian terminology.– geoadria, 8/1, 17–37. http://hrcak.srce.hr/index.php?show=clanak&id_clanak_ je­ zik=14843 terzić, j., marković, t. & lukač reberski, j. (2014): hydrogeolo­ gical properties of a complex dinaric karst catchment: miljacka spring case study.– environ earth sci, 72/4, 1129–1142. doi: 10.1007/s12665­ 013­3031­6 toran, l. & reisch, c. e. (2013): using stormwater hysteresis to cha­ racterize karst spring discharge.– groundwater, 51/4, 575–587. doi: 10.1111/j.1745­6584.2012.00984.x torres-martínez, j. a., mora, a., knappett, p. s. k., ornelassoto, n. & mahlknecht, j. (2020): tracking nitrate and sulfate sources in groundwater of an urbanized valley using a multi­tracer ap­ proach combined with a bayesian isotope mixing model.– water res, 182, 115962. doi: 10.1016/j.watres.2020.115962 usgs (2021): phreeqc v. 3.7.3.15968. software release 5 december 2021. url: https://www.usgs.gov/software/phreeqc­version­3 vasić, l., živojinović, d. & rajaković-ognjanović, v. (2020): hydrochemical changes and groundwater grouping data by multivariate statistical methods within one karst system: recharge–discharge zone (eastern serbia case study).– carbonates and evaporites, 35/1, 15. doi: 10.1007/s13146­019­00548­6 wei, t. & simko, v. (2021): r package ‘corrplot’: visualization of a corre­ lation matrix. (version 0.92), https://github.com/taiyun/corrplot. white, w. (1997): thermodynamic equilibrium, kinetics, activation barri­ ers, and reaction mechanisms for chemical reactions in karst terrains.– environ geol, 30, 46–58. doi: 10.1007/s002540050131 yurtsever, y. & gat, j. (1981): atmospheric waters. stable isotope hydrology: deuterium and oxygen­18 in the water cycle.– in: gat, j.r. & gonfiantini, r. (eds.): technical reports series 210, iaea, vienna, 103–142. zemann, m., wolf, l., grimmeisen, f., tiehm, a., klinger, j., hötzl, h. & goldscheider, n. (2015): tracking changing x­ray contrast media application to an urban-influenced karst aquifer in the wadi shueib, jordan.– environ pollut, 198, 133–143. doi: 10.1016/j.en­ vpol.2014.11.033 živanović, v., jemcov, i. & dragišić, v. (2022): vulnerability meth­ ods in hard rock formation as a basis for groundwater risk assessment – from resource to source.– geol croat, 75, 381–392. doi: 10.4154/ gc.2022.23 https://www.usgs.gov/software/phreeqc-version-3 g eologia c roatica 157selak et al.: hydrochemical characterization of a dinaric karst catchment in relation to emerging organic contaminants figure s1. correlation matrix of physicochemical parameters for jadro (a), žrnovnica (b), gizdavac (c), and cetina (d) (correlation coefficients order with aoe algorithm – the angular order of the eigenvectors). values marked with x are not significant. supplement 1. – figure s1 g eo lo gi a c ro at ic a 158 geologia croatica 77/2 table s1. results of shapiro-wilk test (values in bold indicate normally distributed data i.e. p-value>0.05) (data october 2019 – october 2022). jadro žrnovnica gizdavac cetina parameter w p-value w p-value w p-value w p-value temperature 0.96 0.35 0.98 0.76 0.90 0.40 0.96 0.42 ph 0.89 0.01 0.92 0.04 0.89 0.34 0.96 0.49 electrical conductivity 0.98 0.83 0.97 0.52 0.93 0.61 0.89 0.01 na+ 0.86 2.36e-03 0.85 1.41e-03 0.89 0.30 0.84 8.02e-04 k+ 0.97 0.73 0.84 1.03e-03 0.80 0.06 0.87 2.93e-03 mg2+ 0.92 4.75e-02 0.94 0.14 0.71 0.01 0.99 1.00 ca2+ 0.97 0.62 0.90 0.02 0.90 0.36 0.87 3.01e-03 cl– 0.84 7.73e-04 0.82 4.68e-04 0.78 0.04 0.85 1.25e-03 hco3 – 0.95 0.28 0.97 0.50 0.95 0.77 0.81 2.28e-04 no3 – 0.76 3.74e-05 0.79 1.02e-04 0.79 0.05 0.78 7.93e-05 so4 2– 0.96 0.40 0.97 0.54 0.87 0.23 0.92 0.04 δ18o 0.96 0.48 0.96 0.43 0.83 0.11 0.86 2.40e-03 δ2h 0.97 0.71 0.94 0.16 0.86 0.18 0.92 0.05 o2 (%) 0.76 4.48e-05 0.93 0.07 0.95 0.77 0.91 0.02 jadro žrnovnica gizdavac cetina table s2. results of kruskal-wallis post hoc dunn test (values in bold indicate significant difference i.e. p.adjusted<0.05) (data october 2019 – october 2022). comparison p. adjusted ca2+ mg2+ na+ cl– hco3 – so4 2– no3 – cetina – gizdavac 1.72e-08 1 1.28e-04 1.94e-03 8.49e-08 5.06e-06 5.11e-06 cetina – jadro 5.14e-12 1 0.34 0.34 2.17e-08 0.13 1.44e-07 cetina – žrnovnica 5.40e-03 0.73 0.3 0.37 6.85e-03 4.60e-05 0.8 gizdavac – jadro 0.71 1 0.01 0.09 0.24 2.64e-03 0.13 gizdavac – žrnovnica 5.63e-04 0.42 0.01 0.08 1.40e-03 0.17 2.64e-03 jadro – žrnovnica 7.63e-04 0.04 1 1 0.05 0.18 6.21e-03 table s3. main statistical descriptors of saturation indices (si) calculated with phreeqc for jadro, žrnovnica, gizdavac, and cetina samples (data october 2019 – october 2022). site statistics calcite (caco3) dolomite (camg(co3)2) anhydrite (caso4) gypsum (caso₄·2h₂o) ja dr o sp rin g min –0.06 –1.22 –3.41 –2.97 max 0.71 0.65 –2.60 –2.16 mean 0.17 –0.51 –2.89 –2.45 median 0.16 –0.49 –2.87 –2.43 žr no vn ic a sp rin g min –0.02 –1.19 –3.49 –3.05 max 1.16 1.49 –2.76 –2.32 mean 0.43 –0.07 –3.04 –2.60 median 0.39 –0.10 –3.03 –2.59 ce tin a ri ve r min 0.37 –0.32 –3.04 –2.55 max 1.11 1.50 –2.56 –2.13 mean 0.79 0.77 –2.82 –2.36 median 0.82 0.77 –2.84 –2.37 g iz da va c bo re ho le min 0.17 –0.93 –3.47 –3.03 max 0.45 0.04 –3.13 –2.68 mean 0.27 –0.43 –3.31 –2.86 median 0.26 –0.42 –3.31 –2.86 supplement 2. – tables s1, s2 and s3. 2022 | 75/2 | 211–222| 8 figs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction breccia is a term used for a rock body that consists of a variety of individual clasts and fragments, which are commonly very angular and may have a fine-grain matrix and/or be cemented together by a mineral cement. the grains within the matrix may not have a similar composition to those of the rock fragments (laznicka, 1988; scholz, 1990). the origin of some breccias can be deduced from their texture, composition, and context (i.e., position within the brecciated body), but the origin or the three-dimensional geometry of other breccias is often uncertain. one problematic breccia formation mechanism is the gravitational collapse into voids formed either by dissolution (loucks, 1999), or by a mismatch of fault walls (e.g. woodcock et al., 2006; ferrill et al., 2011; walker et al., 2011). the pag town breccia body exposed west of pag town on the island of pag (fig. 1) highlights this dilemma. the stratigraphic position of the breccia is very close to the top of the upper cretaceous shallow-water carbonate succession capped with two unconformities; the older one which represents a regional emersion event lasting from the late cretaceous till the early eocene (e.g., durn et al., 2003; otoničar, 2007; korbar, 2009; brlek et al., 2013; peh & kovačević galović, 2016), and a younger emergence event, occurring during the early eocene that was much shorter but of indeterminate duration (a few millions of years?). both unconformities indicate long-term exposure during which karstification could develop in the relatively near-surface sections. for example, as the fractures in the exposed surfaces were enlarged over time by chemical dissolution, more flow the origin of a complex breccia body within the upper cretaceous/early eocene succession on pag island (karst dinarides, croatia): karstic dissolution and collapse or dilational faulting and collapse origin? dražen kurtanjek*, damir bucković, darko tibljaš and blanka cvetko tešović department of geology, faculty of science, university of zagreb, horvatovac 102a, hr-10000 zagreb, croatia; (*corresponding author: drkurtan@geol.pmf.hr) doi: 10.4154/gc.2022.15 abstract a kilometre west of pag town on pag island, croatia, within the upper cretaceous shallow-water carbonate succession, there is a large breccia body that has an irregular, quasi-circular shape and a subvertical-oblique position in relation to the bedding of the host rock. the breccia clasts and fragments consist almost entirely of the upper cretaceous host rock with only sporadic clasts of the lower eocene foraminiferal (alveolinid) limestones. in the brecciated body, there are three breccia types. 1) crackle breccia, 2) mosaic breccia, and 3) chaotic breccia. based on the textural and structural characteristics of these types of breccia such as chaotic appearance and random fabric, very poorly sorted material, angular fragments, the composition reflecting only the host rock lithology, two genetic scenarios or concepts for the origin of pag town breccia body were considered, with observations supporting each of them. the first concept involves host rock dissolution resulting in a widened dissolution cavity into which wall and roof rocks progressively collapsed, and the second concept involves the collapse of voids produced by dilational fault displacement. a common prerequisite to both opposing scenarios is the existence of a subsurface cavity or void where the accumulation of rock clasts and fragments occurred. it is assumed that the timing of the cavity formation is related mainly to karstification during the late cretaceous-early eocene emersion phase or is related to dilational faulting during the palaeogene dinarides thrusting event. is directed into the fractures. the fracture conductivity increases by several orders of magnitude with increasing fracture width. consequently, flow in a mature karst aquifer is characterized by efficient drainage through the fractures, which, when sufficiently enlarged, become cave systems (kaufmann & braun, 2000). alternatively, the presence of easily recognizable fault zones in the study area may also indicate the grinding action of two fault blocks as they slide past each other forming a dilationalfault void that underwent subsequent collapse. the objective of this investigation is to describe the structural setting and the composition, texture, and fabric of this breccia body and provide observations related to two postulated origins that can be used to suggest an interpretation of the genesis of the breccia body. 2. geological setting the island of pag is situated in the north-eastern part of the adriatic sea (fig. 1). the area is characterized by gentle folds, striking in the northwest, dinaridic direction (majcen et al., 1970). the fold limbs are refolded and faulted by local strike-slip fault systems. geomorphologically, the observed anticlines correspond to the elongated upland ridges and highs, while the synclines correspond to the narrow, shallow karstic valleys. the anticlines are composed of upper cretaceous rudist limestones and dolomites, and lower – middle eocene foraminiferal limestones. the synclines are filled with middle–upper eocene flysch clastics, sandstones, and marls, and are covered by the quaternary deposits (see majcen et al., 1970; mamužić et al., 1970; sokač et al., 1974 for details). the island of pag is located along article history: manuscript received september 10, 2021 revised manuscript accepted february 14, 2022 available online june 23, 2022 keywords: breccia, karstic dissolution, dilational faulting, upper cretaceous, pag island, karst dinarides g eo lo gi a c ro at ic a geologia croatica 75/2212 the ne adriatic coast, which is a part of the adriatic carbonate platform (adcp vlahović et al., 2005, also referred to as the adriatic–dinaridic carbonate platform – adcp – jenkyns, 1991; gušić & jelaska, 1993; pamić et al., 1998; jelaska, 2003), being one of the largest mesozoic and most longlasting carbonate platforms in the mediterranean region. the adcp comprises a 4–6.5 km thick succession of almost pure carbonate rocks deposited from the early jurassic to the end of the cretaceous (vlahović et al., 2005). it represents a significant part of the thicker succession (in places more than 8 km thick; tišljar et al., 2002; velić et al., 2002; vlahović et al., 2005) of mostly carbonate strata, which today form the karst dinarides (or external dinarides), with a stratigraphic range of more than 300 ma (the oldest outcrops are of carboniferous age; ramovš et al., 1990; temkova, 1990; sremac, 2005). this succession was originally deposited on the adria microplate, which represented a promontory of africa during the mesozoic (channell et al., 1979; schmid et al., 2008 and references therein). the succession is now incorporated into a complex imbricated thrust and fold belt characterized mostly by sw vergences, extending for more than 600 km along the ne adriatic coast (korbar, 2009 and references therein). by the end of the cretaceous, large areas of the platform emerged, and the area of deposition on the platform gradually reduced (durn et al., 2003; otoničar, 2007; korbar, 2009; brlek et al., 2013; peh & kovačević galović, 2016, and references therein). at the end of the cretaceous, a regional emergence took place, followed by karstification and sporadic bauxite formation. transgressive lower eocene foraminiferal limestones with evidence of sporadic emersion events commonly overlie this regional erosional surface recording foreland basin deposition of foraminiferal limestones on a carbonate ramp with progressive deepening and transition into flysch-type deposition (drobne et al., 1991; košir, 1997; marjanac & ćosović, 2000; vlahović et al., 2005; babić & zupanič, 2016 and references therein). 3. methods fieldwork included detailed mapping of the study area at 1:25000 scale and sampling breccia fragments for microscopic analyses and facies-type characterization. a petrographic study of thinsections was done using plane-polarized transmitted light. rock slabs and thin-sections were stained using a mixture of alizarin red s and potassium ferricyanide dissolved in a dilute hydrochloric acid solution in order to differentiate carbonate minerals (dickson, 1966; evamy, 1969). three breccia samples, four individual clasts samples separated from breccia, and four host rock samples were treated with 3.4% hydrochloric acid aiming to determine their insoluble residue content. x-ray powder diffraction (xrpd) analyses were performed on the insoluble residue of these samples and on one sample of the breccia matrix using a philips pw3040/60 x’pert pro diffractometer equipped with cu tube (40 kv and 40 ma) and proportional counter. given the small quantity of material, si zero-background sample holders on the spinner stage were used in parallel beam geometry (multilayer parabolic x-ray mirror). the relatively large iron content resulted in the high background, therefore several samples that were available in greater quantity (necessary for classic al-holders) were also scanned with divergent beam geometry that included a graphite monochromator. in this case, the following slits were used: mask 10 mm, 1/2° divergence slit, 1° and 2° antiscatfigure 1. (a) location map with the geographic position of the pag town breccia outcrop (circle) (coordinates: 44° 26’ 14.19’’ n, 15° 02’ 15.96’’ e) and (b) simplified geological map of the study area. legend: a) e1 – lower eocene, b) k2 3 – coniacian-lower campanian, c) k2 2 – upper turonian, d) strike and dip (notice the difference between dip and dipping direction of the surrounding host rock contrary to those of blocks within the breccia body), e) sampling positions, f ) geologic boundary, g) faults, h) breccia body g eologia c roatica kurtanjek et al.: the origin of a complex breccia body within the upper cretaceous/early eocene succession on pag island ... 213 ter slits on the tube and detector side respectively, and a 0.2 mm receiving slit. the samples were scanned in continuous mode at a speed of 0.02°2θ/s. diffraction patterns were processed using the x’pert highscore computer program (panalytical, 2004) and compared with the powder diffraction file database and with data from the literature (brown, 1961; brindley & brown, 1980; moore & reynolds, 1997). 4. stratigraphic position in the outcrop area, west of pag town (fig. 1), a 97 m thick section of the breccia occurs within the uppermost turonian to lower campanian carbonate succession (figs. 1b and fig 2). the breccia body generally has irregular margins to the adjacent upper cretaceous host rock. in the lower section of the host rock, the limestone succession containing the breccia body is bioclastic wackestone/ packstone/floatstone, composed of angular to subrounded bioclasts mainly derived from rudistid and other bivalves. the surrounding carbonate matrix generally contains calcareous dinoflagellate cysts (calcispheres, pithonellas) and various other fine-grained bioclasts such as echinoderm fragments, pelagic crinoids, sponge spicules, and echinoid spines. such bioand lithofacies characteristics can be correlated with the upper part of the sveti duh formation, originally described from the island of brač (gušić & jelaska, 1990), and represent the gradual recovery of shallow-platform environments after a drowned phase during the lower turonian. overlying these deposits are light gray to reddish-brown, moderately recrystallized mudstone and bioclastic wackestone/packstone/grainstone/floatstone limestone types, with various indeterminable miliolids, ataxophragmiids, rotaliids, thaumatoporellaceans (thaumatoporella parvovesiculifera (raineri)), calcimicrobes (decastronema kotori (de castro)), rudist (radiolitidae), echinoderm and gastropod fragments, ostracods, peloids and intraclasts. rare irregular fenestrae are also common. among the foraminifera, the most common are; scandonea samnitica de castro, pseudocyclammina sphaeroidea gendrot, cretaciclavulina gusici schlagintweit & cvetko tešović, montcharmontia compressa de castro, nezzazatinella picardi (henson) and psudonummoloculina spp. such bioand lithofacies indicate that these limestones were deposited in shallow subtidal environment, corresponding to the typical gornji humac formation (gušić & jelaska, 1990). therefore, the stratigraphic position of the host rock limestone succession surrounding the breccia body can be defined within the time interval from the late turonian to early campanian (from ca. 87 to 80 ma). 5. breccia features the breccia body geometry is irregular, quasi-circular, and is oriented subvertically-obliquely to the bedding of the host rock (fig. 1b). the northern, uppermost margin of the breccia body is faulted, revealing a straight contact plane with the upper cretaceous host rock (fig. 1b). these faults have approximately e w to ne sw strikes and are almost vertical. higher in the succession, at the cretaceous early eocene contact, there is a major left-lateral strike-slip fault striking nw se (fig. 1b). the breccia fragments are almost entirely composed of the surrounding host rocks, containing the same microfossil association. in chaotic breccias in several areas near the central part of the breccia body, sporadic pebble-sized fragments of lower eocene foraminiferal (alveolinid) limestone are noted (fig. 2). the breccia fragments range in size between a few millimetres to more than two metres diameter. many of the clasts can be designated as blocks (fig. 3a), slabs (fig. 3b), and chips (fig. 3c). davies (1949) and white & white (1969) defined blocks as masses of rock that still show bedding, slabs as fragments of single beds, and chips as bits of bedrock. the dip directions (from 200°–250°) of the blocks are different and even opposite to the dip directions of host rock strata (40°) (see in fig. 1b). clast shape is variable, but elongated and equidimensional clasts are the most common (fig. 3). roundness is low, with most clasts being angular to subangular, while in the stratified parts of the breccia the clasts may be subrounded to rounded (fig. 4a). throughout the breccia body, the breccia fragments can be observed in different interrelationships. therefore, the observed breccia fabrics can be classified into non-genetic breccia categories proposed by loucks & handford (1992), as well as in those of loucks (1999) for cave-collapse zones, or into the categories modified by mort & woodcock (2008), woodcock & mort (2008) for fault zone breccias. these categories include: (1) crackle breccia when the rock is highly fractured with thin fractures separating breccia clasts (fig. 3d); (2) mosaic breccia; when displacement between clasts is greater and some of the clasts are rotated (upper part of fig. 3e); this type includes both matrix-free and matrix-rich varieties. the crackle breccia, and mosaic breccia are present at the edges of the breccia body and are monomictic, that is they contain fragments of just one type of the host limestone. (3) chaotic breccia, is characterized by a predominantly polymictic composition and extensive rotation and displacement of clasts derived from different surrounding beds. figure 2. simplified geological column showing the occurrence of the breccia body within the upper cretaceous succession. g eo lo gi a c ro at ic a geologia croatica 75/2214 figure 3. examples of the characteristic types of breccia-fragments and non-genetic categories of the studied breccia: (a) block – a mass of rock that still shows bedding (marked with an ellipse) representing a rotated fragment of host rock within chaotic breccia. the dip direction of layers in this block (200°) is opposite to the dip direction of layers in the host rock (40°); person in front for scale 185 cm tall. (b) slab − a fragment of a single bed (more than 2m long) within a coarse-clast chaotic breccia. (c) chip – coarse-clast chaotic breccia fragment representing a bit of host rock; (b) and (c) rock hammer for scale (35 cm long). (d) crackle breccia – highly fractured host rock with thin fractures separating breccia clasts. there is no displacement or any sign of transport of clasts. note monomictic composition and tight fitting of clasts and noticeable reddish colouration. the small area (upper left) displays some more chaotic clasts organization. (e) mosaic breccia – displacement between the clasts is greater than in crackle breccia. some of the clasts have been rotated but the fitting is still recognizable. there is a transition from crackle breccia (upper part of the photo) to mosaic breccia (lower part of the photo). both types of breccia are monomictic. (f) chaotic breccia – internally disorganized polymictic breccia. clasts have been rotated and translated enough to obscure any match with each other. chaotic breccia appears as matrix free clastsupported (b, f), matrix-rich clast-supported (g), and matrix-supported type (h). clasts shape varies from elongated to equidimensional, roundness is low with most clasts being subangular to angular (b, f, g, h). coarse-clast chaotic breccia (a−c, f) belongs to one of six basic cave facies recognized in a palaeocave system (proposed by loucks & mescher, 2001) interpreted as collapsed-breccia cavern fill characterized by a mass of very poorly sorted granuleto bouldersized fragments of surrounding rocks that host the breccia. (e), (f), (g), (h) double-arrow line for scale 20 cm. g eologia c roatica kurtanjek et al.: the origin of a complex breccia body within the upper cretaceous/early eocene succession on pag island ... 215 clasts within the chaotic breccia have been rotated and translated to a point sufficient to obscure any match with each other (figs. 3b, c, f). the chaotic breccia appears as a matrix free clast-supported breccia (figs. 3b, f), matrix rich clast-supported breccia (fig. 3g), and a matrix-supported breccia (fig. 3h). the matrix within the matrix-rich type of breccia is a mixture of fineto micro-breccia material (fine breccia equals fragment sizes between 1–5 mm, spry, 1969; micro-breccia equals average clasts size of 0.2 mm, higgins, 1971), and detrital calcite silt. clast-supported chaotic breccia prevails; it occupies the lower half and some of the upper parts of the breccia body, while the matrixsupported chaotic breccia appears only as a narrow zone within the upper half of the breccia body. some breccias show stratification defined by clast shape and size, with lineation and poor development of imbricated pebbles (fig. 4a). other breccias show obstacle marks (fig. 4f), and some show a ribbon to tabularshaped breccia body, characterized by an irregularly undulating top and inversely graded clasts (fig. 4b). the dip of the brecciated strata is not parallel with the host rock stratification. fitted fabric, convex-concave, and sutured contacts between the grains and wavy stylolites with iron oxide-stained pressuredissolution seams are very common features of the breccia (figs. 4c, 5a). figure 4. facies determined in the studied breccia that match the basic palaeocave facies proposed by loucks & mescher (2001) (a, b, d, e) and some specific textural-structural features of the breccia (c, f): (a) finer-clast breccia displaying crude packaging and stratification defined by clast shape and size interpreted as hydrodynamically sorted, transported-breccia cavern fill. some pebbles show lineation and poorly developed imbrication and are mostly subrounded to rounded; meter for scale 42 cm. (b) inversely graded coarse-clast chaotic breccia displaying ribbon to tabular shaped body with the irregular, undulating top representing another variety of the same facies shown in fig. 3a−c, f−h; double-arrow line for scale 90cm. (c) detail of chaotic breccia showing common fitted fabric, concaveconvex and sutured contact between the grains, and fine-breccia material between larger clasts. reddish-brown fine-grained pore filling sediment is insoluble residue material. (d) host rock strata with visible bedding continuity; for scale-man in the picture is 185 cm tall. dip direction and dip: 40/66 (e) disturbed host rock strata. the bedding is visible but is folded and offset by small faults; the notebook at the left part of the outcrop is 20 cm long and 14.5 cm wide for scale. dip direction and dip: 40/45. (f) detail of chaotic breccia showing obstacle mark, a structure formed by secondary currents which originate when the main streamflow is obstructed by obstacles within the path of the current. coarse particle (boulder in the centre) was anchored to the bottom, the current was not able to remove it, and a shadow zone (upper left) is created by its protrusion. smaller particles can find protection in the shadow zone, where turbulence and velocity are reduced, and come to rest; meter for scale 42 cm. g eo lo gi a c ro at ic a geologia croatica 75/2216 figure 5. (a) fitted fabric resulting from strong mechanical and chemical compaction. wavy and sutured, microstyloltitic contacts between the grains are lined with the pressure-dissolution seams. original pores are filled with detrital/crystal ferroan calcite silt. plane-polarized light. stained with alizarin red s and k-ferricyanide. (b) typical breccia pore-filling cement. the calcite spar has a well-developed drusy mosaic fabric characterized by an increasing crystal size towards the centre of the cavity. detrital and crystal calcite silt fill the inner, uncemented pore space. both calcite spar and crystal silt turn blue after treatment with alizarin red s and k-ferricyanide indicating ferroan calcite with a late diagenetic, burial origin. plane-polarized light. stained with alizarin red s and k-ferricyanide. (c) microkarstic dissolution-cavity filling pattern similar to (b) but here, the drusy calcite spar and crystal silt have a non-ferroan composition (red colouration after staining) indicating an origin during early, near-surface diagenesis of microkarstic dissolution and cementation. this type of cavity-infill with non-ferroan calcite spar and detrital calcite silt occurs solely within the clasts and were formed in the original sediment i.e. in the surrounding breccia-host rock prior the brecciation. plane-polarized light. stained with alizarin red s and k-ferricyanide. (d) example of breccia pore-filling composed of a mixture of detrital and crystal calcite silt, silt-sand sized quartz grains, and insoluble residue material. crossed polarized light. (e−g) fissure-filling cements found within breccia-clasts. some fissures are cemented with ferroan calcite spar (blue) and some with non-ferroan calcite spar (red) indicating different stages of cementation. fissures cemented with non-ferroan calcite spar are found only within the clasts and are inherited from host rocks as a result of prebrecciation processes. note that the fissure filled with ferroan calcite spar transects the fissure filled with non-ferroan calcite spar indicating its later origin (e) and that fissures filled with blueish stained calcite spar can cut both the clasts and the matrix (f, g). micro-breccia material between larger grains is also visible, upper left in (f) and lower part in (g). micro-breccia material is interpreted as a result of rebrecciation processes related to tectonic and burial stress released during the late diagenetic phase. pore spaces within the micro-breccia are completely filled with ferroan (blue) detrital calcite silt (lower part in g). plane-polarized light. stained with alizarin red s and k-ferricyanide. (h) example of breccia poregeopetal infill where detrital calcite silt occupies the lower part of the pore representing the earlier fill regarding the calcite spar above (central part). other pores are completely filled with detrital calcite silt (upper left). blue colour of calcite spar and detrital calcite silt after treatment with alizarin red s and k-ferricyanide indicating their ferroan nature and late diagenetic, burial origin. plane-polarized light. stained with alizarin red s and k-ferricyanide. g eologia c roatica kurtanjek et al.: the origin of a complex breccia body within the upper cretaceous/early eocene succession on pag island ... 217 the intergranular pores and fissures within the breccia are cemented, but in some original pore spaces where spar fill is absent or incomplete the pores are now: a) completely or partially filled with cement crystals or detrital calcite silt (fig. 5a, b); b) filled with a reddish/yellowish-brown mixture of detrital calcite silt, silt/sand-sized quartz grains, and with a material that is assumed to be insoluble residue (fig. 5d); or c) filled with reddish/ yellowish-brown mixture of fineto micro-breccia and detrital calcite silt (figs. 4c, 5f–h). where calcite cement and detrital silt occur together within a void, the detrital silt either fills the centre, uncemented part of voids (fig. 5b), representing a later filling episode, or geopetally occupies the lower part of the voids, representing the earlier fill event before the overlying cement precipitated (fig. 5h). calcite spar, as well as calcite detrital silt, filling intergranular pores and fissures within the breccias, turns blue after alizarin red s and potassium ferricyanide treatment indicating the cements are ferroan. these cements are predominantly equant ferroan-calcite spar with drusy fabric characterized by crystal size increasing towards the cavity centre (fig. 5b). crystals may reach nearly 1 mm in diameter in the centre of the cavities. fissures within the breccia with ferroan calcite fill, are located within the clasts, but also extend through the lithified matrix, cutting both the clasts and the matrix (fig. 5f, g). on the other hand, there are fissures and dissolution-widened cavities that are confined within the clasts that reveal cementation with non-ferroan drusy mosaic calcite spar and detrital calcite-silt fill (fig. 5c). geopetally arranged infills of such cavities in different clasts show up orientations that vary indicating some rotation of clasts and therefore the deposition of cavity-infills before brecciation. also, fissures filled with ferroan calcite spar transect the fissure filled with non-ferroan calcite spar, indicating a later origin for the ferroan calcite fill (fig. 5e). recognition of identical fissures and dissolution-cavities within the host rock characterized by the presence of the nonferroan calcite spar and/or detrital silt and by the identical infill pattern indicates that the same type of cavities and associated cementation patterns found within clasts were formed in the original host rock, during earlier near-surface diagenesis of host rocks that were later brecciated. the insoluble residue content of the limestones that host the breccia and of individual clasts that were separated from breccia averages 1%. the insoluble residue content of the breccias as a whole is three times greater. xrpd analyses show that insoluble residues of host rock and separated breccia clasts contain quartz, kaolinite, and illitic material while the dominant mineral phases in the insoluble residues of breccias are quartz, kaolinite, illite, and goethite, with haematite, smectite, and anatase being present in subordinate amounts (fig. 6). xrpd analysis of the matrix as a whole showed that calcite is the dominant constituent, while quartz, anatase, goethite, and illite are present as minor or trace components. it was very difficult to collect enough pure sample of the matrix to obtain the appropriate amount of insoluble residue for xrpd analysis because of the specific occurrence of the matrix as a thin coating around the grains and its high calcitic composition. therefore, the composition of the insoluble residue of the matrix was deduced by combining the results of xrpd analyses of the insoluble residue of clasts and breccias and of xrpd analysis of the matrix as a whole. accordingly, the mineral composition of the insoluble residue of the matrix is quartz, goethite, haematite, smectite, anatase, and illite. 6. discussion many authors have written about the appearance of local and regional palaeokarstic periods and breccias in the adcp area during the late cretaceous and palaeogene, providing different interpretations as to their origin (e.g. prtoljan & glovacki jernej, 1994; durn et al., 2003; otoničar, 2007; korbar, 2009; venturini & tentor, 2010; brlek et al., 2013; peh & kovačević galović, 2016; otoničar, 2016). however, based on the geological setting and stratigraphic position of the pag town breccia body (figs. 1, 2), its textural and structural characteristics such as chaotic appearance and random fabric, very poorly sorted material, angular fragments, composition reflecting only the host rock lithology, we present two genetic figure 6. xrd patterns of insoluble reisdues of a breccia clast [a], and whole breccia [b]. a – anatase, ggoethite, i – illite, k – kaolinite, q – quartz, and s – smectite. cu kα radiation. g eo lo gi a c ro at ic a geologia croatica 75/2218 scenarios or concepts for the origin of this breccia body (fig. 7). the first concept involves host rock dissolution resulting in a widened dissolution cavity into which wall and roof rocks progressively collapsed and detrital sediment was imported (fig. 7a), as described by many authors (e.g. choquette & james, 1988; kerans, 1988, 1993; loucks, 1999; cooper & keller, 2001; loucks, 2007). an alternative scenario involves the origin of the breccia by collapse of voids produced by dilational fault displacement (fig. 7b), or by a mismatch of fault walls (e.g. woodcock et al., 2006; woodcock et al., 2014). thus, both concepts assume the gravitational collapse of blocks and slabs into an open void. the size of the original void may be the same as the breccia body, but it is typically smaller since the brecciated zone following collapse usually becomes wider than the original void (loucks, 1999). the question is whether the void originated by karstic dissolution or by extensional/transtensional tectonics. regardless of which mechanism led to the formation of the breccia body, its characteristics today are mashed, more or less masked, and overprinted by polyphase tectonic and diagenetic alterations. 6.1. karstic dissolution and collapse scenario palmer (1991) used a database of approximately 500 caves to develop statistics on the relative abundance of different modern cave system types. he concluded that approximately 92% of all cave types are products of near-surface karst processes (epigenic cave systems). esteban (1991) noted that extensive palaeokarst is more commonly associated with composite unconformities than with a single unconformity. composite unconformities represent long exposure times that may be more than 4 ma in duration and may coincide with two or more third-order regressive cycles. a new cycle of karst will develop during each cycle of exposure, and each newer karst cycle will overprint the previous cycle. an older system may be abandoned and collapse and then be overprinted by one or more younger systems (loucks, 1999). however, extensive palaeokarsts could also be related to a single unconformity, a good example being the cretaceous-palaeogene palaeokarst phase of the adcp (otoničar, 2007). it is also possible that long-lasting palaeokarsts show less pronounced palaeokarst features than shorter-lasting palaeokarsts (melim et al., 2002). the upper cretaceous host rocks in the studied area, as well as in the entire area of the adcp, were exposed to subaerial, nearsurface processes during the late cretaceous–early eocene regional emersion phase (e.g. jelaska et al., 1994; ćosović et figure 7. schematic diagram of the two possible genetic concepts of breccia origin discussed in the paper (modified after woodcock et al., 2014). figure 8. model showing the final stage of cave collapse during burial with six basic cave facies recognized by rock fabric and structures (modified after loucks & mescher, 2001). numbered facies refer to those found in the study area. subsidiary faults could be a secondary effect of movement on the main fault or could be attributed to suprastratal deformations that occur as a result of the final collapse during burial. g eologia c roatica kurtanjek et al.: the origin of a complex breccia body within the upper cretaceous/early eocene succession on pag island ... 219 al., 1994; matičec et al., 1996, cvetko tešović et al., 2020). the duration of the emersion phase was different on various parts of the platform, ranging from 0 ma to 90 ma (korbar, 2009; španiček et al., 2017; otoničar, 2007; peh & kovačević galović, 2016), but in the studied area it lasted at least ca. 25ma (korbar, 2009). in the studied area, the lower eocene foraminiferal (alveolinid) limestones were also subjected to a significant local emergence event of indefinite duration (local tectonic uplift?), that is clearly observed within the exposed lower eocene shallow-water carbonate sequence. these two emergence occurrences lasted longer than 25 ma, which corresponds to esteban’s (1991) criterion of long-term exposure of 4 ma. during each period of such prolonged subaerial exposure, the preburial cave of a near-surface karst environment could enlarge and partly collapse and fill with the debris of the surrounding host rock. the features such as microkarstic voids partially filled with internal sediment (fig. 5c), dissolution enlargements of tectonically induced fractures, and reddish (haematitic) colouration frequently found within the upper cretaceous rocks and within the numerous breccia fragments, are clear indications of the subaerial exposure and dissolution of the upper cretaceous host rock. in addition, a very common occurrence of fissures in numerous breccia fragments that are inherited from the host rocks indicates some late cretaceous tectonic stresses prior to brecciation processes (fig. 5e–g). this could lead to easier and more efficient dissolving-fluid activity when significant karstification processes took place and eventually could lead to extensive void formation. indubitably, all these features visible in numerous breccia fragments indicate that near-surface dissolution processes preceded the brecciation in the study area. this appears to be the case that is common in long-term composite unconformities where there is more than one karst event. the presence of insoluble residue material incorporated into the breccia matrix, and a mineralogy strongly correlated with the insoluble residues of the host rocks, also suggests that dissolution processes were most likely involved in breccia formation. loucks & mescher (2001) proposed a classification of six common palaeocave facies (fig. 8). four of them can be recognized within the studied breccia body so their presence may be evidence of the karstic dissolution and collapse scenario. these are: (1) undisturbed strata, which are interpreted as undisturbed host rock (fig. 4d). in this facies, bedding continuity can be traced even for tens of hundreds of metres. (2) disturbed host rock strata around the collapsed passage (fig. 4e). here, the bedding continuity is high, but it is weakly folded and offset by small faults. it is commonly overprinted by crackle and mosaic brecciation. (3) coarse-clast chaotic breccia is interpreted as collapsedbreccia cavern fill produced by ceiling and wall collapse (figs. 3a−f, 4b). it is characterized by a mass of very poorly sorted, granuleto boulder-sized chaotic-breccia clasts that can be graded. it is commonly clast supported but can contain matrix material. (4) finer-clast stratified chaotic breccia (fig. 4a) interpreted as hydrodynamically sorted, transported-breccia cavern fill characterized by a mass of clast-supported, moderately sorted granuleto cobble-sized clasts with varying amounts of the matrix. clasts can be imbricated. furthermore, the textural and structural characteristics of the breccia body indicate that the transport distance of the breccia fragments was very short (mosaic breccia with short gravitational displacement with or without rotation of fragments; fig. 3e) or, in places, there is practically a complete absence of any transport at all (highly fractured crackle breccia; fig. 3d). also, the appearance of breccia intervals displaying the sedimentary structures such as inverse grading, stratification, imbrication, and obstacle marks (fig. 4a, b, f) indicate void sediment fills deposited by hydrodynamically induced processes such as traction by subterranean streams or mass-flow mechanisms (loucks, 1999). based on the presence of these features that can only occur in an open space, there had to be a cavern connected to the surface within the upper cretaceous carbonate succession. the presence of sporadic pebble-sized fragments of lower eocene foraminiferal (alveolinid) limestone in the central part of the breccia body, a few tens of metres below the lower eocene succession, can only be explained by the presence of underground voids/channels. after the lithification of the lower eocene limestone, thin vadose karst channels/cracks cut through the underlying layers, large enough only for transport of pebble-sized lithified lower eocene limestone clasts into the subsurface void before the final cave roof collapse during burial. nevertheless, if we consider a karstic solution and collapse scenario during the long-lasting late cretaceous–early eocene emersion and subsequent short-lasting early eocene emersion, some of its features may be controversial. one of the controversies is reflected in the fact that if such a big underground void existed and extended more than a few tens of metres below the late cretaceous/early eocene palaeokarstic surface, one would expect at least some cave phenomena visible among the void breccia fragments, i.e., various allogenic and autogenic cave phenomena speleothems such as flowstones or some bauxite clasts formed on the palaeokarst surface. no such underground or surface palaeokarstic features can be found, neither near the studied breccia body nor within its fragments. but actually, speleothems and bauxite deposits are not commonly expected in caves. many modern caves today have no or rare speleothems so the lack of speleothems is a poor criterion for interpreting a non-karst origin. loucks (1999) has observed that speleothems could occlude a relatively minor fraction of pore volume in the whole cave system. palmer (1995) also referred to a similar observation of the lack of speleothems from his studies. ford & williams (1989) noted that some caves are totally devoid of speleothems, whereas in other caves they may be common. speleothems, therefore, should not be expected as obligatory defining characteristics for all palaeocave systems; however, where they are encountered in the ancient stratigraphic record, they are good indicators of karst processes. with regard to the lack of bauxite fragments, the mineral composition of the surrounding strata should be taken into consideration. since the host rocks are 99% calcite, their insoluble residues could make little contribution to the formation of bauxite, although conditions for intense leaching were present because of the active vertical drainage through fractured limestones. the aluminosilicate-rich parent material should be present for extensive bauxite formation. in a pure limestone terrain such as this, the aluminosilicate-rich material is present only in a very small amount. therefore, the accumulation of such material is usually sporadic and localized, so bauxite formation was not expected to occur everywhere on the emergent surfaces. furthermore, the fact that the final void collapse in this scenario occurred during burial can also be quite controversial. usually, cave ceilings become less stable closer to the surface because g eo lo gi a c ro at ic a geologia croatica 75/2220 a rock-ceiling beam may lose support especially if there are numerous fractures in the ceiling. such a cantilevered rock beam across a cave ceiling is able to resist gravitational stress in direct proportion to its thickness and inversely proportional to its length (white & white, 1969). that is why there are numerous examples of caves as stable forms deep below the surface, even from the dinarides. although palaeocaves are able to resist overburden pressure, they are also affected by tectonic stresses that can trigger cave collapse even in the subsurface burial environment. movements of the neighbouring main strike-slip fault (fig, 1b) have the potential to act in the same way. emphasized form-fitting fabric, extensive convex-concave and sutured contacts between grains, as well as pressure solution seams, stylolites, and numerous fissures cemented with a ferroancalcite spar of drusy mosaic fabric, indicate a strong influence of secondary diagenetic processes during burial on producing the final breccia features visible today. indirectly, this also implies the absence of extensive early near-surface breccia-cementation, as its presence would reduce the impact of later mechanical and chemical compaction. 6.2. dilational-fault void and collapse scenario it is very intriguing that a dilational faulting and collapse scenario could also produce the same types of breccia (woodcock et al., 2006; mort & woodcock, 2008; woodcock & mort, 2008; woodcock et al., 2014). several faults are visible in the studied area. one of the faults intersects and displaces the northern, uppermost part of the breccia body and represents a fault with vertical and horizontal displacement (fig. 1b). since it intersects the breccia body, it must have been formed after brecciation, so it could not have influenced the formation of the breccia body. two minor faults striking ne sw bound the northern margin of the breccia within the upper cretaceous strata and another one does not cut the breccia body (fig. 1b); therefore, these faults cannot be involved in the formation of the breccia either. the main fault, a left-lateral strike-slip fault, separates the upper cretaceous and eocene deposits (fig. 1b) and is not in contact with the breccia body. it could be assigned to the main dinaridic thrust-related deformation event where the complex tectonic structure of the whole region was formed that occurred during the palaeogene (aubouin et al., 1970; chorowitz, 1977; cadet, 1978; pamić et al., 1998; tari, 2002; schmid et al., 2004). although this fault may have had the potential for producing brecciation along the fault plane, there is no visible brecciated zone immediately adjacent to the fault line. fault influence is also questionable because it is not in direct contact with the breccia body. nonetheless, the proximity of this major strike-slip fault might have affected the surrounding rock. although this fault is not in direct contact with the breccia body, movements along its main slip surface could affect the neighbouring strata and trigger successive void collapses in both near-surface and subsurface areas. however, in any case, that does not imply the conclusion that this particular fault is responsible for the creation of the void. in addition, minor faults near this main fault could be attributed to subsidiary faults as a secondary effect of the movement on the main fault or be assigned to suprastratal deformations occurring because of final collapse during burial (loucks, 2007) (fig. 8). as the cavity collapsed during burial, overlying strata could sag or subside over the collapsed area, providing potential for the development of a fracture/fault system that can extend upwards from the collapsed interval. this effect is recorded at horizons more than 800 m above the cavity (loucks, 1999, 2007). thus, if we consider such a dilational faulting and collapse scenario during the main paleogene dinaridic thrust deformations, a controversy also arises. that is, if the studied breccia body was formed exclusively by the gravitational collapse of a fault-void or by direct fault fragmentation, the geometry of the breccia body should be conformable and parallel with the fault line (cooper & keller, 2001; woodcock et al., 2014). here, however, there are no visible faults striking parallel to the breccia body. in addition, the absence of some other indicators of collapse into fault-induced voids, such as clasts of crackle and mosaic breccia in the chaotic breccias, representing fragments of faulted wall rock collapsed into the fault void and slickensided clasts from the fault walls (woodcock et al., 2014), further excludes the possibility of such a scenario. irregular margins and irregular quasi-circular breccia-body geometry, inconsistent with bedding, additionally do not support the scenario of dilational faulting and collapse. in contrast, it is a regular and common feature of dissolution processes to form the voids for subsequent breccia infill (cooper & keller, 2001; woodcock et al., 2014). 7. conclusion if we consider the pros and cons for the two presented/discussed scenarios, the conclusion arises that the karst dissolution and collapse scenario is the most probable scenario for the pag town breccia origin. except for the fact that dilational-fault void collapse can produce the same type of breccia as karst dissolution void collapse, no other breccia features support the dilational faulting and collapse scenario for the pag town breccia origin. taking into account all of the data presented, the formation of the pag town breccia can be interpreted as follows. during the emersion phase from the late cretaceous to the early eocene, the karstification of the exposed upper cretaceous host rock occurred, accompanied by intense local fracturing. the fractures allowed easier and more intense penetration of fluids into the host rock, resulting in intense host rock (limestone) dissolution. the resulting and expanding subsurface void in the preburial phase was gradually and partially filled with upper cretaceous limestone fragments, both from its ceiling and walls. these rock fragments were even partially transported along the void by mass flow mechanisms and subsurface currents, resulting in clearly visible inverse grading, stratification, imbrication, and obstacle marks. during the early eocene, another local emergence of an undetermined duration occurred. at that time, when the cave was only partially filled, only sporadic pebbles of lithified foraminiferal limestone of the early eocene age entered the subsurface void through the narrow passages. thus, in preburial, near-surface conditions during each phase of prolonged subaerial exposure the subsurface void developed and partly collapsed. as burial progressed, the cracked roof of the void eventually collapsed and completely filled the remaining open space (fig. 8), burial cementation with ferroan calcite spar occurred, mechanical compaction increased, and restructured the breccia fragments and remaining cavities. continued burial led to further extensive mechanical and chemical compaction resulting in expressive, form-fitting structures, formation of stylolites, and rebrecciation/ refragmentation of some clasts leading to the formation of a fine to microbrecciated matrix. in addition to gravitational stresses caused by the weight of the overlying strata, tectonic stresses induced by the movements of the adjacent main strike-slip fault may have been the trigger for the collapses near the surface and especially in the subsurface. g eologia c roatica kurtanjek et al.: the origin of a complex breccia body within the upper cretaceous/early eocene succession on pag island ... 221 references aubouin, j., blanchet, r., cadet, j.-p., celet, p., charvet, j., chorowicz, j., cousin, m. & rampnoux, j.-p. (1970): essai sur la géologie des dinarides.– bull. soc. géol. fr. sér., 7, 12, 1060–1095. doi: 10.2113/gssgfbull.s7xii.6.1060 babić, lj. & zupanič, j. (2016): the youngest stage in the evolution of the dinaric carbonate platform: the upper nummulitic limestones in the north dalmatian foreland, middle eocene, croatia.– nat. croat., 25/1, 55–71. doi: 10.20302/ nc.2016.25.3 brindley, g.w. & brown, g. (1980): crystal structures of clay minerals and their x-ray identification.– min. soc., london, 495 p. doi: 10.1180/mono-5 brlek, m., korbar, t., cvetko tešović, b., glumac, b. & fuček, l. (2013): stratigraphic framework, discontinuity surfaces, and regional significance of campanian slope to ramp carbonates from central dalmatia, croatia.– facies, 59, 779–801. doi: 10.1007/s10347-012-0342-0 brown, g. (1961): the x-ray identification and crystal structures of clay minerals.– min. soc., clay minerals group, london, 544 p. cadet, j.p. (1978): essai sur l’évolution alpine d’une paléomarge continentale; les confi ns de la bosnie-herzegovine et du monténegro (yougoslavie).– mem. soc. geo. f., 133, 1−83. channell, j.e.t., d’argenio, b. & horváth, f. (1979): adria, the african promontory, in mesozoic mediterranean palaeogeography.– earth-sci rev., 15/3, 213−292. doi: 10.1016/0012-8252(79)90083-7 choquette, p.w. & james, n.p. (1988): introduction.– in: james, n.v. & choquette, p.w. (eds.): paleokarst, 1−21, springer, new york. chorowitz, j. (1977): etude geologique des dinarides le long de la structure transversale split-karlovac (yugoslavie).– unpubl. ph. d. thesis, publ. soc. geol. nord, villeneuve d ascq., 11, 1−331. cooper, j.d. & keller, m. (2001): paleokarst in the ordovician of the southern great basin, usa: implications for sea-level history.– sedimentology, 48, 855−873. cvetko tešović, b., martinuš, m., golec, i. & vlahović, i. (2020): lithostratigraphy and biostratigraphy of the uppermost cretaceous to lowermost palaeogene shallow-marine succession: top of the adriatic carbonate platform at the likva cove section (island of brač, croatia).– cretaceous research, 114, 104507. doi: 10.1016/j.cretres.2020.104507 ćosović, v., balončić, d., koić, m., marjanac, t., moro, a., gušić, i. & jelaska, v. (1994): paleontological evidence of paleogene transgression on adriatic carbonate platform.– geol. mediterr., 21/3–4, 49–53. davies, w.e. (1949): features of cave breakdown.– national speleothem society bulletin, 11, 34–35. dickson, j.a.d. (1966): carbonate identification and genesis as revealed by staining.– j. sediment. petrol., 36/2, 491−505. drobne, k., vlahović, i., trutin, m., pavlovec, r., ćosović, v., babac, d., cimerman, f., lučić, d. & pavšič, j. (1991): excursion b – ravni kotari, paleogene.– in: vlahović, i. & velić, i. (eds): some aspects of the shallowwater sedimentation on the adriatic carbonate platform (permian to eocene), 2nd international symposium on the adriatic carbonate platform, excursion guidebook. institute of geology, zagreb, 53–70. durn, g., ottner, f., tišljar, j., mindszenty, a. & barudžija, u. (2003): regional subaerial unconformities in shallow-marine carbonate sequences of istria: sedimentology, mineralogy, geochemistry and micromorphology of associated bauxites, palaeosols and pedo-sedimentary complexes.– in: vlahović, i. & tišljar, j. (eds): field trip guidebook: evolution of depositional environments from the palaeozoic to the quaternary in the karst dinarides and the pannonian basin, 22nd ias meeting of sedimentology, institute of geology, zagreb, 209–255. esteban, m. (1991): palaeokarst: practical applications.– in: wright, v.p., esteban, m. & smart, p.l. (eds.): palaeokarst and palaeokarstic reservoirs: university of reading, postgraduate research for sedimentology, pris contribution no. 152, 89−119. evamy, b.d. (1969): the precipitational environment and correlation of some calcite cements deduced from artificial staining.– j. sediment. petrol., 39/2, 787−821. ferrill, d.a., wyrick, d.y. & smart, k.j. (2011): coseismic, dilational‐fault and extension‐fracture related pit chain formation in iceland: analog for pit chains on mars.– lithosphere, 3/2, 133–142. doi: 10.1130/l123.1 ford, d.c. & williams, p.w. (1989): karst geomorphology and hydrology.– unwin hyman, london, 601 p. doi: 10.1007/978-94-011-7778-8 gušić, i. & jelaska, v. (1990): stratigrafija gornjokrednih naslaga otoka brača u okviru geodinamske evolucije jadranske karbonatne platforme (upper cretaceous stratigraphy of the island of brač within the geodynamic evolution of the adriatic carbonate platform).– opera acad. sci. art. slav. merid. zagreb, 69, 160 p. gušić, i. & jelaska, v. (1993): upper cenomanian-lower turonian sea-level rise and its consequences on the adriatic-dinaric carbonate platform.– geol. rundsch., 82/4, 676−686. higgins, m. w. (1971): cataclastic rocks.– prof. pap. u.s. geol. surv., 687, 97p. jelaska, v., gušić, i., jurkovšek, b., ogorelec, b., ćosović, v., šribar, l. & toman, m. (1994): the upper cretaceous geodynamic evolution of the adriatic–dinaric carbonate platform(s).– geol. mediterr., 21/3–4, 89–91. doi: 10.3406/ geolm.1994.1534 jelaska, v. (2003): carbonate platforms of the external dinarides.– in: vlahović, i. & , j. (eds.): evolution of depositional environments from the palaeozoic tothe quaternary in the karst dinarides and the panonian basin. 22nd ias meeting of sedimentology. field trip guidebook, 67−71 p. jenkyns, h.c. (1991): impact of cretaceous sea level rise and anoxic events in the mesozoic carbonate platform of yugoslavia.– am. assoc. pet. geol. b., 75, 1007−1017. kaufman, g. & braun, j. (2000): karst aquifer evolution in fractured, porous rocks.– water resources research, 36/6, 1381–1391. doi: 10.1029/1999wr900356 kerans, c. (1988): karst-controlled reservoir heterogeneity in ellenberger group carbonates of west texas.– am. assoc. petr. geol. b., 72, 1160−1183. kerans, c. (1993): description and interpretation of karst-related breccia fabrics, ellenburger group, west texas.– in: wilson, j.l. & yurewicz, d.a. (eds.): paleokarst related hydrocarbon reservoirs, 18, sepm core workshop, 181−200. korbar, t. (2009): orogenic evolution of the external dinarides in the adriatic region: a model constrained by tectonostratigraphy of upper cretaceous to paleogene carbonates.– earth-sci. rev., 96, 296−312. doi: 10.1016/j.earscirev.2009.07.004 košir, a. (1997): eocene platform-to-basin depositional sequence, southwestern slovenia.– gaea heidelbergiensis, 3, 205 p. laznicka, p. (1988): breccias and coarse fragmentites: petrology, environments, associations, ores.– developments in economic geology, 25, 351 p. loucks, r.g. (1999): paleocave carbonate reservoirs: origins, burial-depth modifications, spatial complexity, and reservoir implications.– am. assoc. petr. geol. b., 83, 1795−1834. loucks, r.g. (2007): a review of coalesced, collapsed-paleocave systems and associated suprastratal deformation.– acta carsologica, 36/1, 121–132. doi: 10.3986/ ac.v36i1.214 loucks, r.g. & handford, r.h. (1992): origin and recognition of fractures, breccias, and sediment fills in paleocave-reservoir networks.– in: candelaria, m.p. & reed, c.l. (eds.): paleokarst, karst related diagenesis and reservoir development: examples from ordovician-devonian age strata of west texas and the mid-continent: permian basin section, sepm publication, 92–33, 31−44. loucks, r.g. & mescher, p. (2001): paleocave facies classification and associated pore types.am. assoc. petr. geol., southwest section, annual meeting, dallas, texas, cd-rom, 18. majcen, ž., korolija, b., sokač, b. & nikler, l. (1970): osnovna geološka karta sfrj 1:100000, list zadar l 33–139 [basic geological map of sfry 1:10000, zadar sheet – in croatian].– inst. geol. istraživanja, zagreb, savezni geološki zavod, beograd. mamužić, p., sokač, b. & velić, i. (1970): osnovna geološka karta sfrj 1:100000, list silba l 33–126 [basic geological map of sfry 1:100000, silba sheet – in croatian].– inst. geol. istraživanja, zagreb, savezni geološki zavod, beograd. marjanac, t. & ćosović, v. (2000): tertiary depositional history of eastern adriatic realm.– vijesti hrvatskoga geološkog drustva, 37, 93–103. matičec, d., vlahović, i., velić, i. & tišljar, j. (1996): eocene limestones overlying lower cretaceous deposits of western istria (croatia): did some parts of present istria form land during the cretaceous?– geol. croat., 49/1, 117–127. melim, l.a., westphal, h., swart, p.k., eberli, g. & munnecke, a. (2002): questioning carbonate diagenetic paradigms: evidence from the neogene of the bahamas.– mar. geol., 185, 27–53. doi: 10.1016/s0025-3227(01)00289-4 moore, d.m. & reynolds, r.c. (1997): x-ray diffraction and the identification and analysis of clay minerals.– oxford university press, oxford, 378 p. mort, k. & woodcock, n.h. (2008): quantifying fault breccia geometry: dent fault, nw england.– j. struct. geol. 30, 701–709. doi: 10.1016/j.jsg.2008.02.005 otoničar, b. (2007): upper cretaceous to paleogene forbulge unconformity associated with foreland basin evolution (kras, matarsko podolje and istria; sw slovenia and nw croatia).– acta carsologica, 36/1, 101–120. doi: 10.3986/ac.v36i1.213 otoničar, b. (2016): stratigraphy and evolution of the forebulge related paleokarst – introduction to excursions a and c.– in: otoničar, b. & gostinčar, p. (eds.): paleokarst: abstracts & guide book, 24th international karstological school classical karst, postojna, 42–50. palmer, a.n. (1991): the origin and morphology of limestone caves.– geol. soc. am. bull., 103, 1−21. doi: 10.1130/0016-7606(1991)103%3c0001:oamolc%3e2.3. co;2 palmer, a.n. (1995): geochemical models for the origin of macroscopic solution porosity in carbonate rocks.– in: budd, d.a., saller, a.h. & harris, p.m. (eds.): unconformities and porosity in carbonate strata: aapg memoir, 63, 77–102. pamić, j., gušić, i. & jelaska, v. (1998): geodynamic evolution of the central dinarides.– tectonophysics, 297, 251–268. doi: 10.1016/s0040-1951(98)00171-1 panalytical (2004): x’pert highscore plus, version 2.1, almelo. peh, z. & kovačević galović, e. (2016): geochemistry of lower palaeogene bauxites – a unique signature for the tectonostratigraphic evolution of part of the croatian karst.– geol. croat., 69/2, 269–279. doi: 10.4154/gc.2016.24 g eo lo gi a c ro at ic a geologia croatica 75/2222 prtoljan, b. & glovacki jernej, ž. (1994): on the orgin of the oklad breccia on the island of brač (southern croatia).– geol. croat., 47/1, 67–72. ramovš, a., hinterlechner-ravnik, a., kalenić, m., karamata, s., kochansky-devidé, v., krstić, b., kulenović, e., mirković, m., petkovsky, p., sremac, j. & temkova, v. (1990): stratigraphic correlation forms of the yugoslav paleozoic.– rend. soc. geol. it., 12, 359−383. schmid, s.m., fügenschuh, b., kissling, e. & schuster, r. (2004): tectonic map and overall architecture of the alpine orogen.– eclogae geol. helv., 97, 93–117. doi: 10.1007/s00015-004-1113-x schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpinecarpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss j. geosci., 101, 139–183. doi: 10.1007/s00015-008-1247-3 scholz, c.h. (1990): the mechanics of earthquakes and faulting.– cambridge university press, 442 p. sokač, b., nikler, l., velić, i. & mamužić, p. (1974): osnovna geološka karta sfrj 1:100000, list gospić l 33–127 [basic geological map of sfry 1:100000, gospić sheet – in croatian].– inst. geol. istraživanja, zagreb, savezni geološki zavod, beograd. spry, a. (1969): metamorphic textures.– pergamon press, london, 1−350. sremac, j. (2005): equatorial shelf of the palaeozoic supercontinent – cradle of the adriatic carbonate platform.– geol. croat., 58/1, 1−19. doi: 10.4154/gc.2005.01 španiček, j., ćosović, v., mrinjek, e. & vlahović, i. (2017): early eocene evolution of carbonate depositional environments recorded in the čikola canyon (north dalmatian foreland basin, croatia).– geol. croat., 70/1, 11–25. doi: 10.4154/gc.2017.05 tari, v. (2002): evolution of the northern and western dinarides: a tectonostratigraphic approach.– european geosciences union stephan mueller special publication series, 1, 223–236. doi: 10.5194/smsps-1-223-2002 tišljar, j., vlahović, i., velić, i. & sokač, b. (2002): carbonate platform megafacies of the jurassic and cretaceous deposits of the karst dinarides.– geol. croat., 55/2, 139–170. doi: 10.4154/gc.2002.14 velić, i., vlahović, i. & matičec, d. (2002): depositional sequences and palaeogeography of the adriatic carbonate platform.– mem. soc. geol. it., 57, 141−151. venturini, s. & tentor, m. (2010): la breccias di slivia: una testimonianza di eventi paleotettonici campiano–maastrichtiano nel carso triestino.– natura nascosta, 41, 1–15. vlahović i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform; paleogeography, main events and depositional dynamics.– palaeogeogr. palaeoclim. palaeoec., 220, 333–360. walker, r.j., holdsworth, r.e., imber, j. & ellis, d. (2011): the development of cavities and clastic infills along fault-related fractures in tertiary basalts on the ne atlantic margin.– j. struct. geol., 33/2, 92−106. doi: 10.1016/j.jsg.2010.12.001 white, e.l. & white, w.b. (1969): processes of cavern breakdown.– national speleothem society bulletin, 31, 83–96. woodcock, n.h. & mort, k. (2008): classification of fault breccias and related fault rocks.– geol. mag., 145, 435−440. doi: 10.1017/s0016756808004883 woodcock, n.h., omma, j.e. & dickson, j.a.d. (2006): chaotic breccia along the dent fault, nw england: implosion or collapse of a fault void?– j. geol. soc. lond., 163, 431−446. doi: 10.1144/0016-764905-067 woodcock, n.h., miller a.v.m. & woodhouse c.d. (2014): chaotic breccia zones on the pembroke peninsula, south wales: evidence for collapse into voids along dilational faults.– j. struct. geol., 69, 91−107. doi: 10.1016/j.jsg.2014.09.019 2021 | 74/3 | 237–252 | 8 figs. | 1 tab. | suppl. 2 | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the neogene pannonian basin system (pbs) (fig. 1a) was part of the central paratethys sea (rögl & steininger, 1983; rögl, 1999; pavelić, 2001; popov et al., 2004; harzhauser & piller, 2007, kováč et al., 2017a). from the oligocene to the late early or early middle miocene however, the sea covered only the nw part of the pbs, whereas its other parts were subaerially exposed or characterized by continental deposition. marine sedimentation became widespread in the entire pbs only during the middle miocene, badenian age. the north croatian basin (ncb, fig. 1b) represents the south-western part of the pbs where specific lacustrine depositional environments developed prior to the marine flooding. the freshwater and brackish sediments contain endemic fauna, complicating biostratigraphic correlation and dating. the exact timing of the initial marine flooding in the ncb is thus currently unknown. estimates of the timing of the marine flooding event in the southern part of the pannonian basin range from 17 ma to 15 ma (hajek-tadesse et al. 2009; premec fućek et al., 2017; hernitz kučenjak et al., 2018; pavelić & kovačić, 2018; sant et al., 2018, 2019; mandic et al 2019a, brlek et al., 2020) and are a matter of debate. the main objective of this paper is to provide new radio-isotopic data using the 40ar/39ar method for tuffs from several localities in the ncb. in combination with micropaleontological analysis (calcareous nannofossils, foraminifera, ostracods and palynomorphs) these ages should enable better understanding of the ncb sedimentary evolution and constrain the middle miocene marine flooding event in the ncb. middle miocene marine flooding: new 40ar/39ar age constraints with integrated biostratigraphy on tuffs from the north croatian basin frane marković1,*, klaudia kuiper2, stjepan ćorić3, valentina hajek-tadesse4, morana hernitz kučenjak5, koraljka bakrač4, đurđica pezelj1 and marijan kovačić1 1 university of zagreb, faculty of science, department of geology, horvatovac 102b, 10 000 zagreb, croatia; (*corresponding author: frane.markovic@geol.pmf.hr) 2 faculty of sciences, vrije universiteit amsterdam, amsterdam, the netherlands 3 geological survey of austria, 1030 vienna, austria 4 croatian geological survey, sachsova 2, 10 000 zagreb, croatia 5 ina – industrija nafte, d.d., rock & fluid analysis, lovinčićeva 4, 10 000 zagreb, croatia doi: 10.4154/gc.2021.18 abstract in the north croatian basin which is located in the southwestern part of the pannonian basin system, miocene tuff deposits have been observed at several localities in the area of banovina, medvednica mt. and slavonia. here we present new 40ar/39ar age results obtained from volcanic glass from the laz tuff (15.42 ± 0.15 ma) intercalated with lacustrine freshwater/brackish deposits, the jovac tuff (15.10 ± 0.06 ma) intercalated with lacustrine freshwater deposits, the čučerje tuff (14.81 ± 0.08 ma) and the nježić tuff (14.40 ± 0.03 ma) both deposited in a marine environment. fossil data (calcareous nannofossils/foraminifera) from the underlying and overlying beds of the tuffs from čučerje and nježić match the geochronological data i.e. nn5 zone and m6 zone were determined. integration of biostratigraphic and geochronological data enable a better understanding of the ncb sedimentary evolution and constrain the middle miocene marine flooding event in the marginal areas of the western part of the ncb at ~15 ma i.e. early/middle badenian boundary. these results together with the existence of lower badenian marine sediments in the sava depression (in the southern part of ncb) suggest it is possible to conclude that during the early badenian in the ncb, freshwater lacustrine and marine environments coexisted. 2. geological setting the north croatian basin (ncb) geographically occupies the southwestern part of the pannonian basin system (pbs) (fig. 1a). the pbs is located between the mountain ranges of the carpathians, alps and dinarides. it is composed of a series of smaller, deep depressions or basins, separated by relatively shallow pre-neogene basement (schmidt et al., 2008; ustaszewski et al., 2014). palaeogeographically it belongs to the central paratethys area (cp) (rögl & steininger, 1983; popov et al., 2004; harzhauser & piller, 2007). the origin of the pbs is considered to be the time when lithospheric fragments of alcapa and tisza dacia were placed in their more or less current position, creating a domain for the initial stage of rifting (e.g. fodor et al., 1989; kováč et al., 2018b). the evolution of the pbs has been subdivided into the syn-rift and post-rift phases (horváth & tari 1999; horváth et al., 2006). the duration of these phases was diachronous across the basin (matenco & radivojević, 2012; balázs et al., 2016). in the southwestern part of the pbs, i.e. in the ncb, the synrift phase lasted from the ottnangian to the middle badenian (pavelić, 2001). it was characterized by tectonic thinning of the crust, isostatic subsidence, increased volcanic activity (pamić, 1997; lukács et al., 2015, 2018; szakács et al., 2018) and a transition from continental to marine sedimentary environments (pavelić & kovačić, 2018). this change was caused by the interplay of extensional tectonics, climate change and eustatic sea level changes. article history: manuscript received march 05, 2021 revised manuscript accepted july 07, 2021 available online october 13, 2021 keywords: 40ar/39ar chronology, tuff, miocene, north croatian basin, central paratethys g eo lo gi a c ro at ic a geologia croatica 74/3238 the post-rift phase started during the middle badenian and extended into the quaternary. during this phase, rifting stopped and subsidence continued due to cooling of the lithosphere (royden, 1988; pavelić, 2001; pavelić & kovačić, 2018). the post-rift phase is characterized by the transition from marine to continental sedimentary environments, a halt in volcanic activity and two compressional phases that caused the inversion of the basin and the uplift of individual blocks (jamičić, 1995; márton et al., 1999, 2002; pavelić, 2001; tomljenović & csontos, 2001; pavelić et al., 2003; ustaszewski et al., 2014). although connections with the mediterranean and the indopacific ocean were established occasionally during the oligocene and the middle miocene (nagymarosy & müller, 1988; steininger et al., 1988; rögl, 1996a; harzhauser & piller, 2007; kováč et al., 2007, 2017; piller et al., 2007; sant et al., 2017), most of the time the pbs was an isolated sedimentary environment. isolation has led to the development of endemic fauna. correlation of pbs miocene sediments to mediterranean sediments is therefore not straightforward (rögl & steininger, 1984; nagymarosy & müller, 1988; steininger et al., 1988). biostratigraphy based on endemic fauna only allows the establishment of regional stages for the central paratethys area (steiniger et al., 1976; modified by hohenegger et al., 2014; mandic et al., 2015; neubauer et al., 2015). the stratigraphic position of the oldest terrestrial deposits of the pbs in the ncb was problematic in the past due to either endemic fossil species or the complete lack of fossils. age data (ca. 18 ma) obtained from pyroclastics intercalated with alluvial deposits from kalnik mt. (mandic et al., 2012; brlek et al. 2020) confirmed their ottnangian age and marked the initial time of depo sition. early miocene environments with alluvial deposits (jamičić et al., 1987) and a salina type lake (šćavničar et al., figure 1. the geographic position of the north croatian basin (ncb) within the pannonian basin system (simplified after cvetković et al., 2019) (a). geographic position of the localities: jovac, laz, čučerje and nježić within the ncb (b). tri filea će ići, tri pdf-a prvi je tekst, drugi je supll file broj 1, a treći je suppl file 2 g eologia c roatica marković et al.: middle miocene marine flooding: new 40ar/39ar age constraints with integrated biostratigraphy on tuffs from the north croatian basin 239 1983) lasted up to the end of the karpatian (pavelić & kovačić, 2018). in the early badenian a fresh-water lacustrine environment was formed (ćorić et al., 2009). this lake covered either the whole area of the ncb (pavelić, 2001) or only the syn-rift depocentres (saftić et al., 2003) forming a system of lakes (mandic et al., 2019a). the lacustrine environment enabled an emergence of fresh-water mollusc and ostracod fauna. sedimentation was accompanied by the deposition of tuffs and tuffites and was influenced by a significant change to a humid climate and water level changes (mutić, 1969, 1973, 1980; jamičić et al., 1987; pavelić et al., 2000; pavelić, 2001). in older studies, the lacustrine deposits were correlated by their freshwater fauna and flora (šikić, 1968; kochansky-devidé, 1979; sokač, 1987; žagar-sakač, 2004), and they were attributed to the ottnangian – karpatian period. palynological study (krizmanić, 1995) suggested an age between the karpatian and early badenian. radio-isotope ages of tuff layers of ~16ma within lacustrine sediments defined an important chronostratigraphic marker (mandic et al., 2012). the transition from lacustrine to marine conditions was gradual in many localities in the ncb (pavelić & kovačić, 2018) except at medvednica mt. (brlek et al., 2016) and the nježić locality (kovačić et. al., 2015a). recent biostratigraphic studies (ćorić et al., 2009; martinuš et al., 2013; brlek et al., 2016) placed the initial marine sedimentation in the early middle badenian. the marine deposition regime persisted until the end of the middle miocene (11.6 ma) when the basin was finally isolated (rögl, 1996a, b; magyar et al. 1999; piller & harzhauser, 2005). 3. methods 3.1. fieldwork four outcrops were studied in the ncb, ranging from 1 – 140m in thickness, that include tuff layers: jovac, laz, čučerje, and nježić. gps coordinates are provided in the results section. the sections were logged in detail, including full lithostratigraphic and sedimentologic descriptions. in addition to recording observations in a field diary, all localities were documented with photos. the immediate underlying and overlying beds of the main tuff layers were sampled for micropaleontological analyses (calcareous nannofossils, foraminifera, ostracods and palynomorphs). the main tuff itself (or the main layers) was sampled at each site for mineralogical analysis i.e. for mineral separation of sanidine for 40ar/39ar dating. for thicker layers of tuff, two samples were obtained, one at the bottom and one at the top of the layer. sample codes are given according to the nearest toponym. 3.2. 40ar/39ar dating bulk tuff samples were crushed, washed, sieved and processed using standard heavy liquid and magnetic separation techniques. volcanic glass was irradiated for 12h at the oregon state clicit facility, together with fish canyon tuff sanidine (fcs). sample and standards were fused and released gas was analyzed on a helix mc noble gas mass spectrometer. for data reduction, the ararcalc software (koppers, 2002) was used, with fcs of 28.201 ma (kuiper et al., 2008), min et al. (2000) decay constants and the atmospheric air value of lee et al. (2006). analytical details are provided in the supplementary file 1 (6.1. & 7.1.) 3.3. palaeontological analysis 3.3.1. calcareous nannofossil analyses six samples from the nježić locality and two samples from the čučerje locality were prepared for calcareous nannofossil analyses. standard preparation techniques for calcareous nannofossil analyses were used as described in perch-nielsen, 1985. before smear slide preparation, a small amount of the sample was dispersed in an ultrasonic bath. the dispersed sample was mounted on the slide and fixed with eukit mounting medium. microscopic analysis was performed using a leica dmlp light microscope with 1000x magnification (cross and parallel nicols). biostratigraphic zones were defined using standard zonation after martini, 1971. 3.3.2. palynological analyses palynological analyses were carried out for samples from laz, čučerje and nježić. standard palynological processing techniques were used to extract the organic matter (e.g. moore et al., 1991; wood et al., 1996). to remove the carbonates and sili ca, samples were treated with cold hcl (15%) and hf (40%). separation of the organic matter from undissolved inorganic components was carried out using a heavy liquid (zncl2, density >2.1 g/cm3). the organic residue was sieved through a 10 μm mesh sieve. for palynomorph analysis, slides were mounted in silicon oil. microscopic analysis was performed using an olympus bh-2 and leica dm2500 microscope (hgi-cgs). photomicrographs were taken using an amscopetm camera adapter connected to the amscope v.3.7 camera software and a leica mc190 hd camera connected to the leica las ez software. 3.3.3. foraminiferal and ostracod analyses all available samples from both underlying and overlying beds of the tuff samples (12 samples in total) were prepared for ostracod and foraminiferal analyses. approximately 200 g of sediment per sample was disintegrated in diluted hydrogen peroxide for 48 hours. samples were then sieved (0.5; 0.25; 0.2; 0.125; 0.09; 0.063 mm) and dried at room temperature. some samples required additional cleaning, so the treatment with hydrogen peroxide was repeated, and then the samples were immersed in an ultrasonic bath for 20 seconds. all microfossil remains (ostracods, foraminfera, fish teeth, claws of freshwater crabs, algal thalli and rhizoliths) were examined under a zeiss stemi 2000 microscope (hgicgs), zeiss stemi sv 11 (university of zagreb) and olympus szx16 stereo microscope (ina). determination of the planktonic foraminifera genera and species was based on cicha et al. (1998); wade et al. (2018) and young et al. (2020). biostratigraphic interpretation was based on ćorić et al. (2009), iaccarino et al. (2011), wade et al. (2011), hohenegger et al. (2014), kováč et al. (2017a), kováč et al. (2018a) and lirer et al. (2019). photomicrographs of the planktonic foraminifera were taken by scanning electron microscope (sem) jeol jsm-6510 lv (ina). for the analysis of benthic foraminifera the dried material (four samples from nježić locality and one sample from čučerje) was repeatedly split by a retsch microsplitter to obtain standard samples with 300 randomly chosen foraminiferal specimens. then the plankton/benthos (p/b) ratio was calculated only for samples rich in individuals (njež-a-b, njež-b-t, njež-c-b and njež-c-t). furthermore, 300 individual benthic foraminifera were picked for further analyses. taxonomic identification of benthic foraminifera followed papp et al. (1978), papp & schmid (1985), cicha et al. (1998), and loeblich & tappan (1988a, b). ecological/palaeoecological requirements of benthic foraminifera species were taken from pezelj et al., 2013 (including all references therein). middle miocene local small benthic foraminifera ecozones for the north croatian basin were g eo lo gi a c ro at ic a geologia croatica 74/3240 defined after pezelj & drobnjak, 2019 and correlated to the regional and standard stages. ostracods were picked but not analyzed statistically. species identifications were based on van morkhoven (1963), meisch (2000), frenzel et al. (2010) and fuhrmann (2012). sem photomicrographs of ostracods, fish teeth and claws of freshwater crab were taken using gold-coated samples in an sem jeol jsm-35cf system at the croatian geological survey. 4. results 4.1. materials – sample location and outcrop description 4.1.1. laz the outcrop is located on medvednica mt. along the road at the laz pass (n45° 57’ 28.36“, e16° 05’ 26.03“) (fig. 1b). the sequence begins with a layer of gray-yellow marl, which is extremely rich in the fossil remains of leaves and ostracods (fig. 2). the thickness of the layer is at least 120 cm, (based on the exposed part of the layer). in the middle of the sequence a thin layer (2-3 cm thick), is prominent being dark green in colour (fig. 2c), which represents only the upper part of the tuff layer. the tuff layer consists of two parts. the lower part is very weathered ochre-brown in colour and relatively coarse-grained (fig. 2c). the upper part is dark green and completely fine-grained (clayey). it can be traced laterally over a length of 10 m. the transition to marls in the overlying bed is gradual. this tuff layer doesn’t look reworked i.e. there are no signs of reworking. the overlying beds are > 2 m thick, and the rest of the sequence is covered with vegetation. above the tuff layer itself, remnants of very delicate ostracod shells were observed. layers 1 to 4 cm thick and fossil leaf remains have been observed in the marl. five samples were taken (fig. 2a). figure 2. stratigraphic columns from localities: jovac, laz, čučerje and nježić with marked sample locations (a); contact between njež-a-t (marl) and njež-a2 (tuff) (b); layer of tuff from laz locality (in between the dashed lines, marked laz-tuff) (c) coin diameter = 2.2 cm. g eologia c roatica marković et al.: middle miocene marine flooding: new 40ar/39ar age constraints with integrated biostratigraphy on tuffs from the north croatian basin 241 4.1.2. jovac in the area of banovina, on the right side of the road leading to the village of jovac, on the saddle before the descent towards the bridge on the stream, a layer of tuff about ten centimetres thick was discovered in the outcrop (n45° 10’ 33.95“, e16° 28’ 03.82“). the tuff layer is gray, clayey and contains large crystals of biotite (up to 1.5 mm), bronze in colour, only in its lower part. this tuff layer doesn’t look reworked i.e. there are no signs of reworking. the underlying layer is composed of a clay rich marl at least 50 cm in thickness. two samples were taken (fig. 2a). 4.1.3. nježić nježić is located in the eastern part of the ncb in the slavonia region near the village of nježić on the southwestern slopes of papuk mt. (n45° 26’ 28.76“, e17° 31’ 52.73“) (fig. 1b). the outcrop is described in (krkalo & mutić, 1978) and is located along a macadam road leading from the village to the northwest, along which a 140-metre-thick sequence can be traced. within this sequence, five lithofacies were distinguished: metagabbro facies, algal limestone facies, marl facies, bioclastic limestone facies and tuff facies (fig. 2). the metagabbro facies occupies the lower 4 metres of the sequence and represents pbs basement rocks and corresponds to the metagabbro of the psunj metamorphic complex (jamičić, 1988). the algal limestones facies transgressively overlies the metagabbro, and is present only in the lower part of the sequence as a 3 metre thick layer. it consists of massive lithothamnium limestone in which there are rhodoliths preserved in some places. marl facies appear along the entire sequence and comprise about 70% of the deposits in the sequence. the marl is most often massive, weakly siltose, rich in microfossil fauna (benthic and planktonic foraminifera), as well as calcareous nanoplankton and fragments of echinoderms and bryozoans. the facies of bioclastic limestones comprises up to 5% of the sequence and appears along the entire sequence in the form of layers of centimetre-decimetre thicknesses. bioclastic limestones are composed of redeposited fragments of algae, foraminifera, molluscs, echinoderms and bryozoans. the tuff facies occupies about 25% of the sequence and is most abundant in its central part. the thickness of the tuff layers ranges from >10 cm to almost 20 m. tuff is fine-grained, light gray to greenish-gray in colour. tuff layers do not show signs of reworking. samples from three layers of tuff (at the bottom and at the top of the tuff layer) and marls from their immediate underlying and overlying beds were taken for analyses fig. 2b. the oldest in the tuff sequence is marked (a), the slightly younger (b) and the youngest (c). 4.1.4. čučerje on the southern slopes of medvednica mt., near the centre of čučerje village (n45° 53’ 45.44“, e16° 03’ 17.80“) (fig. 1b) along the stream, there is a steep outcrop described in the literature as the plaz or podplaz locality. a sequence of 42 m in thickness can be observed. the first to describe this outcrop was gorjanovićkramberger (1923) followed by other studies: kochansky-devidé (1944, 1956), šikić (1968), avanić (1995b, 1997) and ćorić et al. (2009). the first 15 metres of the sequence consist of marls and silts intercalated with thin layers of sand. the middle part consists of partially stratified sands and sandstones, while the upper part of the sequence contains a layer of tuff (~36m) and marl. the outcrop marked “čučerje” is located in a very steep cut in the forest about twenty metres east of the outcrop described as the podplaz locality. the sequence (fig. 2a) begins with a layer of limestone on top of which there is a 2m thick layer of gray tuff. the beds overlying the tuff consist of marl. the tuff layer is coarse-grained in the lower part with relatively large biotite crystals (up to 1.5 mm), while the upper part of the tuff layer is finegrained. the tuff layer doesn’t show signs of reworking. limestone from bottom deposits marked čuč-b, coarse-grained tuff marked čuč-tuff and marl from the overlying beds čuč-t were sampled (fig. 2a). the underlying and overlying beds of the tuff described in the podplaz outcrop are siltstones and limestone. these are not present in our section, so these two tuffs cannot be correlated based on lithology. based on the small distance (20 m) from the podplaz outcrop and the close position (altitude) of the layers, the sequence on the čučerje outcrop is very likely a continuation of the podplaz outcrop, so the tuff from the čučerje sequence is younger than the one exposed at the podplaz outcrop. 4.2 40ar/39ar dating results and age interpretation an overview of the results is displayed in tab. 1 and fig. 3. all the relevant analytical data is presented in supplementary tables for both samples and standards: jovac, čučerje, laz and nježić, fish canyon sanidines with sample codes f7, f8 and f9 (supplementary file 1: 1.1.–5.4. & 8.1.). the standard data yield a k/ca ratio between ~11-100 with radiogenic 40ar contents of ~99%. the weighted mean j value or neutron flux parameter/monitor of the three standards is reproducible and yields 0.0030906 ± 0.0000010 (n=20/21; mswd 1.37). ten fusion experiments with ~5 grains per hole for the 250500 μm jovac glass fraction (vu101-r2) were performed. the samples have low k/ca ratios. glass can have issues with ar retention or excess argon mcdougall & harrison (1999). however, the radiogenic argon content is around 90% which is good for a low k sample and results range from 14.99 ± 0.12 ma to 15.77 ± 0.03 (supplementary material – file 1: 2.1–2.3). note that spread in 40ar/39ar ages is also observed in other studies, although not necessarily in volcanic glass (de leeuw et al, 2010, 2013; mandic et al., 2012). the observed scatter can be explained by several potential mechanisms: 1) open system behaviour, i.e. argon (resulting in ages that are too young) and/or potassium loss (resulting in ages that are too old); 2) mixed age populations of volcanic glass implying some sort of reworking of the volcanic tuffs; 3) contamination with older detrital minerals. based on the data obtained it is not possible to test to what extent these factors had an impact on the observed ages. comparison of multiple vs. single grain data from miocene tuffs is discussed by sant et al., 2020. a reliable isochron could not be defined, but there are no indications for excess argon. the youngest dated samples might approach eruption age best if they did not suffer from argon loss. the table 1. summary of the 40ar/39ar results. locality weighted mean age (ma) n n mswd material nježić 14.40 ± 0.03 3 10 2.08 volcanic glass čučerje 14.81 ± 0.08 4 10 1.45 volcanic glass jovac 15.10 ± 0.06 4 10 0.96 volcanic glass laz 15.42 ± 0.15 12 20 1.64 volcanic glass mswd mean square weighted deviates, n is the number of experiments used to calculate the weight mean age, n is the total number of fusion experiments. errors are ±1σ analytical errors (not including uncertainties in standard age and decay constants). g eo lo gi a c ro at ic a geologia croatica 74/3242 weighted mean age of the 4 youngest analyses derived an age of 15.10 ± 0.06 ma. note that a multiple grain fraction was analysed which might obscure further complexity in the data set. twenty fusion experiments with ~10 grains per hole were performed on the 125-250 μm grainsize fraction of volcanic glass of the laz tuff (vu101-r6). samples are low in k and show somewhat lower in radiogenic 40ar yields (on average ~69%). due to the low k content beam intensities are low and analytical uncertainties are relatively large (±0.4 ma). due to the spread in ages (supplementary – file 1: 3.1.–3.3.), it is difficult to derive an eruption age accurately. when using the approach to include the highest number of analyses with a mswd smaller than the t test statistic at the 95% confidence level, a weighted mean age of 15.42 ±0.15 ma was calculated, based on 12 out of 20 analyses. note, that the inverse isochron does not show evidence of excess argon. ten fusion experiments with ~5 grains per hole of 250-500 μm glass from the čuč-tuff (vu101-r7) were performed. samples are also low in k and also somewhat lower in radiogenic 40ar (on average ~87%). due to the spread in ages (supplementary – file 1: 4.1.–4.3.), it is difficult to derive an accurate eruption age. the youngest dated samples might approach eruption age assuming that argon loss did not occur. using the same approach as above, the youngest ages were included in the weighted mean age until the mswd is larger than the t test statistic at 95% confidence level. this yields a weighted mean age of 14.81 ± 0.08 ma based on 4 out of 10 analyses. also for this sample the isochrons are poorly defined, but do not suggest the presence of excess argon. ten fusion experiments with ~5 grains per hole on 250-500 μm nježić – a1 volcanic glass (vu101-r9) were performed. it is also difficult for this sample to arrive at an accurate eruption age (supplementary – file 1: 5.1.–5.4.). the youngest date of ~10ma only has 4% radiogenic 40ar and is excluded. using the approach of including the youngest ages in a weighted mean until the mswd > t-test at 95% confidence, the calculated weighted mean age 14.40 ± 0.03 ma based on 3 out of 10 analyses was derived. note that the 4 oldest analyses show excess argon and provide an inverse isochron age of 15.02 ± 0.07 ma. 4.3. micropalaeontology 4.3.1. calcareous nannofossil assemblages calcareous nannofossil assemblages were determined for six samples from the nježić locality and two samples from the čučerje locality (fig. 2a). distributions of the calcareous nannofossil assemblages can be found in supplementary – file 2: table 1. and illustrations of most of the species in fig. 4. at the nježić locality, samples are rich in very well-preserved nannofossils. the assemblage from the sample njež-a-b is dominated by small sized reticulofenestrids (reticulofenestra minuta roth, 1970, reticulofenestra haqii backman, 1978) and coccolithus pelagicus (wallich 1877) schiller, 1930. presence of sphenolithus heteromorphus deflandre 1953 and the absence of helicosphaera ampliaperta bramlette & wilcoxon, 1967 allow determination of the nn5 zone (martini, 1971). in the sample njež-a-t, a very similar nannofossil assemblage is present. even though the zonal marker species, s. hete­ reomorphus has not been discovered, the whole assemblage dominated by r. minuta indicates the nn5 zone. the absence of s. hetereomorphus could be due to the palaeoenvironmental characteristics of the depositional environment. the remainder of the samples from this locality have very similar nannofossil assemblages, contain zonal marker species s. heteromorphus and are therefore attributed to the nn5 zone. in the sample njež-c-b numerous diatoms were also observed, which indicate an increased concentration of nutrients. the čuč-b sample contains rare, relatively well-preserved forms with helicosphaera cf. waltrans theodoridis, 1984. the presence of sphenolithus cf. heteromorphus and the appearance of h. cf. waltrans allow determination of the lower part of the nn5 zone. c. pelagicus dominates the assemblage, indicating a nearshore depositional environment, probably with strong upwelling characteristics. the čuč-t sample is rich in well-preserved calcareous nannofossils dominated by small reticulofenestrids (r. minuta, r. haqi) and helicosphaera carteri (wallich 1877) kamptner, 1954. the assemblage has a low diversity, probably due to limited palaeoecological conditions. numerous small reticulofenestrids, together with h. carteri indicate a nearshore, nutrient rich depositional environment. the lower part of the nn5 zone can be determined, although s. heteromorphus was not found in the sample. 4.3.2. palynology a total of seven samples from laz, čučerje and nježić have been analyzed. at the laz locality, four samples were analyzed. all samples are dominated by gymnosperm pollen (mostly pinus, fig. 5b), phytoclasts and resin. beside conifers in the sample lazb1, the fern spores polypodium and lygodium were determined. laz-b2 contains, beside conifers, fern spores polypodium and the chlorophyte algae botryococcus sp. (fig. 5a), that is tolerant to brackish conditions. figure 3: 40ar/39ar data of fusion analysis. all data are shown in (a). data excluding outliers are shown in (b). ~5 grains are fused simultaneously for jovac, čučerje and nježić; ~10 grains are fused simultaneously for laz. 1 sigma analytical errors are shown. the analyses included in weighted mean ages are shown in green. for the nježić locality an alternative age is represented by blue dots. the green/blue boxes represent the weighted mean age and standard error with data points excluded until mswd < t-test statistic. the light gray box represents the total spread. the darker gray box represents the mean age and standard deviation. g eologia c roatica marković et al.: middle miocene marine flooding: new 40ar/39ar age constraints with integrated biostratigraphy on tuffs from the north croatian basin 243 the laz-t1 sample has the same assemblage, while the lazt2 sample also contains fern spores verrucingulatisporites cf. rugosus (fig. 5c). at the čučerje locality, only one sample (from the marl overlying the tuff) was analyzed. among the abundant pollen of conifers, common pollen of the riparian tree carya and relatively rare fern spores polypodium were determined. infrequent findings of the marine dinocyst spiniferites pseudofurcatus (fig. 5e) and homotryblium tenuispinosum (fig. 5d) point to unstable coastal environments. at the nježić locality, only two samples from the middle part of the sequence were suitable for analysis, marls from the underlying and overlying beds of the nježić b1/b2 tuff. from the underlying marl, sample njež-b-b contains, besides a rare tropical-subtropical marine, the lagoonal dinocysts polyspha­ eridium zoharyi, also a chlorophyte algae botryococcus sp. that is tolerant to brackish conditions. high concentrations (> 90%) of the cysts p. zoharyi (fig. 5f) and rare prasinophyte phycoma hidasia sp. in the overlying bed, from sample njež-b-t have also been found. 4.3.3. ostracods five samples were used for ostracod analyses, four samples from the laz locality (laz-b1, laz-b2, laz-t1, laz-t2) and one sample from the jovac locality (jov-b). ostracods were found in all samples, and the ostracod specimens were differently preserved. carapaces and valves are well preserved in the sample from the jovac locality, while all samples from the laz locality contain deformed and strongly calcified ostracods. eleven ostracod taxa were identified of which most of the species remained in open nomenclature. distributions of ostracod species recorded in the miocene sediments of the investigated locality are summarized in the supplementary – file 2: table 4, listed alphabetically, and most of the species are illustrated in fig. 6. figure 4. photomicrographs of calcareous nannoplankton species: (1a) cyclicargolithus floridanus (roth & hay, in hay et al., 1967) bukry, 1971 (1b) reticulofenestra minuta roth, 1970; (2, 3) coccolithus miopelagicus bukry, 1971; (4) helicosphaera walbersdorfensis muller, 1974; (5) reticulofenestra gelida (geitzenauer 1972) backman 1978; (6a) coccolithus pelagicus (wallich 1877) schiller, 1930 (6b) helicosphaera carteri (wallich 1877) kamptner, 1954; (7, 8) sphenolithus heteromorphus deflandre 1953; (9a) reticulofenestra minuta roth 1970; (9b) helicosphaera carteri (wallich 1877) kamptner, 1954 (9c) sphenolithus heteromorphus deflandre 1953; (10, 11a) coccolithus pelagicus (wallich 1877) schiller, 1930 (11b) umbilicosphaera jafari muller, 1974; (12, 13) umbilicosphaera rotula ( kamptner, 1956) varol, 1982; (14) coccolithus pelagicus (wallich 1877) schiller, 1930; (15) rhabdosphaera sicca (stradner, 1963) fuchs & stradner 1977; (16) sphenolithus moriformis (brönnimann & stradner, 1960) bramlette & wilcoxon, 1967; (17, 18) sphenolithus heteromorphus deflandre 1953; (19) ponto sphaera multipora (kamptner, 1948 ex deflandre in deflandre & fert, 1954) roth, 1970. nr: 1 – 15 & 19 are from sample: njež-c-t; 16, 17 & 18 are from sample čuč-b. g eo lo gi a c ro at ic a geologia croatica 74/3244 ostracod fauna recorded in the five samples included eleven ostracod species that represent four families: cypridopsis cf. bi­ planata, herpetocypris sp., herpetocypris cf. reptans and hete­ rocypris sp. within cyprididae; candona sp., pontoniella sp. and cypria sp. (candonidae); paralimnocythere cf. rostrata within limnocytheridae; and amnicythere sp. and leptocythere ? sp. figure 5. photomicrographs of palynomorps from samples a: botryococcus, laz-b2; b: pinus, laz-b2; c: verrucingulatisporites cf. rugosus, laz-t2; d: homotryblium tenuispinosum, čuč-t; e: spiniferites pseudofurcatus njež-b-b; f: polysphaeridium zoharyi, njež-b-t) figure 6. sem photomicrographs of selected microfossils from laz and the jovac locality: a, c candona sp., sample laz t1; b cypria sp., sample laz t1; d paralimnocythere cf. rostrata, sample laz t1; e leptocythere ? sp., sample laz t2; f claw of freshwater crab, sample laz b2; g, pontoniella sp., sample laz t1; h amnicythere sp,. sample laz b1; i potamocypris sp., sample jov b; j herpetocypris sp., sample laz b1; k herpetocypris cf. reptans, sample jov b; l fish tooth, sample laz b1. scale bars: 100 μm. g eologia c roatica marković et al.: middle miocene marine flooding: new 40ar/39ar age constraints with integrated biostratigraphy on tuffs from the north croatian basin 245 within leptocytheridae. the most common records are of the genus herpetocypris (present in 5 samples), and candona (present in 3 samples), followed by amnicythere, heterocypris and cypria (in 2 samples). only one genus herpetocypris is present with two species, while another genus is represented by only one species. species richness is generally low. in addition to the ostracods, the investigated samples contained additional micropalaeontological remains, such as planktonic and benthic foraminifera, algal thalli (sample jov-b ) and rhizoliths (sample jov-b ), fish teeth (samples laz-b1 and lazt2) and the claws of freshwater crabs (laz-b2 and laz-t2). 4.3.4. foraminifera 4.3.4.1. planktonic foraminifera at the nježić locality six samples have been analyzed. the distribution of the foraminifera from the marl samples is given in the supplementary – file 2: table 2. the foraminiferal assemblage in the njež-a-b sample is diverse and well preserved. representatives of the trilobatus genera (t. trilobatus, t. quadrilobatus, t. sicanus) are very frequent in the planktonic foraminiferal association. specimens of paragloborotalia mayeri and praeorbulina curva have also been observed. planktonic foraminifera species determined in the njež-a-b sample have a somewhat wider stratigraphic range and suggest a late early badenian to middle badenian age (m5-m6 zone – according to wade et al., 2011 and mmi4c to mmi5 – according to lirer et al., 2019). sample nježa-t has a poorly preserved and less diverse planktonic foraminife ra assemblage suggesting the same age (late early badenian to middle badenian). in the sample njež-b-b the foraminiferal assemblage is relatively well preserved, with a slightly lower degree of biodiversity. specimens of the genus paragloborotalia predominate but t. trilobatus, praeorbulina curva, globigerina tarchan­ ensis etc. have also been identified. the assemblage indicates the late early badenian to middle badenian (m5 to m6 zone – according to wade et al., 2011 and mmi4c to mmi5 – according to lirer et al., 2019). in the sample njež-b-t planktonic foraminifera are relatively well preserved. in the planktonic foraminiferal association, beside numerous representatives of the genera paragloborotalia, the species praeorbulina curva, p. glomerosa and p. cf. circularis have been observed. the assemblage suggests a middle badenian age (m6 zone – according to wade et al., 2011; mmi4d to mmi5 – according to lirer et al., 2019). in the njež-c-b sample a well-preserved assemblage of planktonic foraminifera (praeorbulina glomerosa, p. circularis, p. curva, trilobatus trilobus) indicates a middle badenian age (m6 zone – according to wade et al., 2011 and mmi4d to mmi5 – according to lirer et al., 2019). in the sample njež-c-t, the planktonic foraminiferal association is diverse and well preserved with numerous specimens of the genera praeorbulina and or­ bulina. the presence of the index fossil orbulina suturalis suggests a middle badenian age – mmi 5a zone (lirer et. al, 2019) and the m6 zone (wade et al., 2011). at the čučerje locality, the marl from the overlying bed of the tuff (čuč-t) has been analyzed. the sample contains globige­ rina bulloides, g. tarchanensis, g. cf. subcretacea, globigerinita cf. uvula, globoturborotalita drury and tenuitella sp. determined species of planktonic foraminifera indicate a badenian age, most likely the middle badenian, however a typical middle badenian assemblage has not been observed. at the laz locality, few findings of planktonic foraminifera have been observed (samples laz-b1 ? trilobatus sp., laz-b2 and lazt2 globoturborotalita cf. pseudopraebulloides). 4.3.4.2. benthic foraminifera benthic foraminiferal assemblages at the nježić locality are well preserved and rich in individuals. the species richness (number of species level taxa) ranges from 27 to 36 per sample (total 54 species, supplementary – file 2: table 3.). along the entire section, the dominating species are cibicidoides ungerianus (d’orbigny), cassidulina laevigata d’orbigny and boliv­ ina dilatata reuss. the abundance of planktonic foraminifera in the samples varies from 80.9% to 94.2%. according to the benthic foraminifera, the studied section belongs to the lagenidae zone (moravian substage of the badenian), middle badenian (sensu hohenegger et al., 2014), traditionally early badenian, but no more precise stratigraphic placement is possible within the lagenidae zone. the index species for the lagenidae zone is uvigerina macrocarinata papp & turnovsky, while uvigerina grilli schmidt is the index species for the lagenidae zone and the spirorutilus zone. also, the determined species vaginulinopsis pedum (d’orbigny) and uvigerina bulbacea (gallowary & heminway) stratigraphically do not cross the upper part of the lagenidae zone. samples from the čučerje locality did not contain enough specimens to support a palaeoecological interpretation. only rare specimens of cibicidoides pseudoungeriana (d’orbigny) and bolivina dilatata (reuss) have been observed. at the laz locality, the benthic foraminifera cibicides sp. has been observed. 5. discussion 5.1. 40ar/39ar geochronology 40ar/39ar dating of tuffs at four localities in the ncb yielded ages of between 14.4–15.4 ma. this is consistent with the main volcanic activity in the pbs (lukács et al., 2015, 2018; szakács et al., 2018) during the syn-rift phase of basin development in the early miocene and the lower part of the middle miocene (pavelić, 2001; pavelić & kovačić, 2018). according to the microfossil assemblages from the underlying and overlying layers of the dated tuffs, a shift from terrestrial to marine environments occurred in parallel with the volcanic activity. the oldest tuffs analysed in this paper, were found in the north-western part of the ncb at the laz locality on mt. medvednica (fig. 1b), where the tuff yielded a 40ar/39ar age of 15.42 ± 0.15 ma (tab. 1, fig. 3). a similar age was obtained for volcanoclastic turbidites from požeška gora in the central part of the ncb, where brlek et al. (2020) dated sanidines and reported a 40ar/39ar age of 15.34 ± 0.32 / 15.43 ± 0.32 ma and ca id -tims u-pb zircon age of 15.345 ± 0.02 ma, respectively, from the same material. similar ages of pyroclastic material were found south of the ncb in the dinaride lake system area (dls). for example, dating of feldspar from tuff deposited in the gacko basin yielded a 40ar/39ar age of 15.31 ± 0.16 ma (mandic et al., 2011; de leeuw et al., 2012) and tuff deposited at the lučane locality in the sinj basin dated on sanidine yielded an 40ar/39ar age of 15.43 ± 0.05 ma (de leeuw et al., 2010, 2012). a slightly younger age is determined along the southern part of the ncb in the banovina area, where the tuff layer at the jovac locality (fig. 1b) is dated at 15.10 ± 0.06 ma. a similar age has not been previously determined in the ncb. in contrast, a tuff with an age corresponding to 14.81 ± 0.08 ma at the čučerje locality on medvednica mt. (fig. 1b) has been described at several localities in the pbs and its surroundings (lukács et al., 2018 and references therein). according to chronostratigraphic similarity, the čučerje tuff can be correlated with the demjén ignimbrite bükkalja volcanic field (bvf) erupg eo lo gi a c ro at ic a geologia croatica 74/3246 tion unit described by lukács et al. (2018). the youngest age of volcanic activity in this paper was determined in slavonia in the central part of the ncb. there, at the nježić locality, the oldest tuff layer from the lower part of the sequence is dated at 14.40 ± 0.03 ma. the thickness of the tuff layers at the nježić locality, reaching up to 18 m, as well as their number in a sequence one hundred metres thick, indicates strong and long-lasting volcanic activity in the middle of the badenian in the ncb area. the fact that the mid-badenian is characterized by strong volcanic activi ty throughout the pbs area is confirmed by layers of volcanic ash of similar age described from several localities. for example, handler et al. (2006) report a 40ar/39ar age of 14.39 ± 0.12 ma on sanidine crystals from the retznei locality in the styrian basin, while de leeuw et al. (2013) report a 40ar/39ar age of 14.37 ± 0.06 ma on sanidine crystals from the dej tuff complex in the transylvanian basin. according to chronostratigraphic similarity, the nježić tuff can be correlated with the harsány ignimbrite bvf eruption unit described by lukács et al. (2018). 5.2. biostratigraphy and depositional environments the microfossil assemblages from the underlying and overlying beds of the studied tuff layers indicate that tuff deposition occurred in different sedimentary environments. for example, the assemblage of ostracods (herepetocypris sp. and the genera cypria and potamocypris) determined in the underlying bed of the tuff layer at the jovac locality in banovina indicates a shallow freshwater lacustrine environment. based on the mollusc and ostracod fauna for the tuffs intercalated with marls at the paripovac locality in the glina sub-depression, and the sjeničak locali ty in the karlovac sub-depression, a freshwater environment was determined (mandic et al., 2012; hajek-tadesse et al., 2016). the age range of the afore-mentioned tuffs from 16.03 ± 0.06 ma at the paripovac locality and 15.91 ± 0.06 ma at the sjeničak locality (mandic et al., 2012) to 15.10 ± 0.06 ma at the jovac locality suggests that the freshwater lacustrine environment existed in the early badenian along the southern boundary of the ncb for at least one million years. south of the ncb, the same sedimentary environments existed in the early badenian, in the dls area, where tuff layers intercalate with freshwater lacustrine sediments in the gacko and sinj basins (mandic et al., 2011; de leeuw et al., 2010, 2012). at the same time, i.e. 15.42 ma ago, a slightly different sedimentary environment existed at the laz locality on medvednica mt., in the north-western part of the ncb, according to tuff dating results. findings of the freshwater but tolerant to brackish water chlorophyte algae botryococcus as well as the discovery of euhaline ostracod species from family leptocytheridae, indicate the existence of a freshwater to brackish water environment. brackish water and the possible ingression of seawater in the laz locality is further supported by findings of a few planktonic (glo­ boturborotalita cf. pseudopraebulloides, ? trilobatus sp.) and benthic foraminifera (cibicides sp.) in samples laz-b1, laz-b2 and laz-t2. findings of the fern spores verrucingulatisporites cf. rugosus (fig. 5c) indicate a late karpatian – early badenian age (nagy, 1985). according to the palynomorph assemblage, deposition occurred in a subtropical coastal freshwater – brackish environment. a similar ostracod assemblage was described in the central part of the ncb on požeška gora (hajek-tadesse et al. 2009; mandic et al., 2019a). such a brackish environment could be the result of occasional seawater ingression into the lake or a consequence of climate change from subtropical humid to more arid conditions (mandic et al., 2019a). the fossil assemblage of calcareous nannoplankton and planktonic foraminifera from the underlying and overlying beds of the tuffs at the čučerje locality on medvednica mt. and the nježić locality on papuk mt. shows that their deposition took place in a marine environment. the presence of sphenolithus cf. hete­ romorphus and the occurrence of helicosphaera cf. waltrans in the calcareous nannofossil assemblages of the čučerje locality enable the determination of the lower part of the nn5 zone, i.e. the upper part of the early badenian according to kováč et al. (2018a) and middle badenian according to hohenegger et al. (2014), which is consistent with the 40ar/39ar age of the tuff layer dated at 14.81 ± 0.08 ma (fig. 8). the dominance of coccolithus figure 7. planktonic foraminifera (nježić) – (1) trilobatus trilobus, njež-a-b; (2) globigerina tarchanensis, njež-b-b; (3) paragloborotalia mayeri, njež-b-t; (4) praeorbulina glomerosa, njež-c-b; (5) praeorbulina circularis, njež-c-b; (6) orbulina suturalis, njež-c-t. scale bar – 100 µm. g eologia c roatica marković et al.: middle miocene marine flooding: new 40ar/39ar age constraints with integrated biostratigraphy on tuffs from the north croatian basin 247 fi gu re 8 . c om pi la tio n of th e re su lts o bt ai ne d by m ic ro fo ss il an al ys is a nd 40 a r/ 39 a r d at in g fo r t he in ve st ig at ed lo ca lit ie s. lo ca lit ie s ar e re pr es en te d in d iff er en t c ol ou rs : n je ži ć – re d; č uč er je – b lu e; jo va c – gr ee n an d la z – br ow n. b ox es re pr es en t t he st ra tig ra ph ic p os iti on o bt ai ne d by m ic ro fo ss il an al ys is a nd th e ci rc le s r ep re se nt th e re su lts o bt ai ne d by 40 a r/ 39 a r d at in g. ab br ev ia tio ns : l o – la st o cc ur re nc e, lc o – l as t c om m on o cc ur en ce , f o – f irs t o cc ur re nc e, b sc – b ad en ia n sa lin ity c ris is, b se e – ba de ni an -s ar m at ia n ex tin ct io n ev en t, ab – a cm e ba se , a e – ac m e en d g eo lo gi a c ro at ic a geologia croatica 74/3248 pelagicus in the underlying bed and numerous small reticulofenestrids as well as the presence of helicosphaera carteri in the overlying bed, also indicate a nearshore sedimentary environment. the badenian age, most likely the middle part of the badenian, is also suggested by the planktonic foraminiferal assemblage. however, the assemblage typical of this period was not found. the palynofacies also suggests that deposition occurred in a marine environment in a subtropical climate during the badenian. at the nježić locality, where the oldest tuff layer is dated at 14.40 ± 0.03 ma, the calcareous nannofossil assemblages allow the determination of the nn5 zone, i.e. the middle part of the badenian (fig. 8). this assemblage is also rich in reticulofenestrids of small dimensions (3 μm), indicating an epicontinental marine environment and a stratified water column. a similar assemblage was observed from the scientific borehole baden-soos from the southern part of the vienna basin (ćorić & hohenegger, 2008). the nn5 zone was also attributed to the dej tuff in the transylvanian basin (mészáros & şuraru, 1991). the assemblage of planktonic foraminifera indicates the m6 zone according to wade et al. (2011) and the mmi4c to mmi5 zones according to lirer et al. (2019), i.e. also the middle part of the badenian. according to the benthic foraminifera, the studied samples from the nježić locality belong to the lagenidae zone (moravian substage of the badenian). correlation with the identified calcareous nannoplankton zone nn 5 (fig. 8), facilitates the conclusion that the studied time interval certainly indicates the upper lagenidae zone, i.e. middle badenian sensu hohenegger et al. (2014) or the early badenian sensu kováč et al. (2018a). a similar cibicidoides­ bolivina­cassidulina assemblage of benthic foraminifera with clear dominance of the species cibicidoides ungerianus (d’orbigny), cassidulina laevigata d’orbigny and boliv­ ina dilatata reuss was identified throughout the section. the high proportion of planktonic foraminifera (>80%) in the nježić samples indicates an upper bathyal environment (murray 2006), while the overlap of depth ranges of benthic foraminifera indicates a deep-water environment of the outer shelf (ca. 200 m). high concentrations (~90%) of polysphaeridium zoharyi cysts (fig. 5f) indicate blooms of a toxic dinoflagellate pyrodinium ba­ hamense (motile stage of p. zohary cyst). increased productivity in both modern and palaeo-oceans has been associated with volcanism (achterberg et al., 2013). abundances (> 50%) of p. zoharyi cysts occur where summer upper temperatures are >29.1°c and winter upper temperatures are >19.1°c (zonneveld & pospelova, 2015). rare prasinophyte phycoma hidasia sp. were also found, indicating shallow-sea and nearshore conditions. according to these findings, a badenian age could be suspected. palaeoenvironmental preferences of ‘’homotryblium complex’’ taxa (pyrodinium/polysphaeridium, eocladopyxis and homotryb­ lium) are discussed by de verteuil & norris (1996). they concluded that ‘’homotryblium complex’’ species are often dominant in dinocyst assemblages with moderate to low diversity, typically in unstable coastal environments. this trend suggests an opportunistic, bloom-forming ecology. this group also appears to reflect warm temperate to tropical palaeoceanographic provinces. pyrodinium bahamense is euryhaline and can be abundant in both low salinity and high salinity waters (dybkjær, 2004). hajek-tadesse (2006); hajek-tadesse & prtoljan (2011) and vesel lukić & hajek-tadesse (2017) published a detailed description of the badenian marine ostracods from the banovina area, čučerje and nježić locality. in the slavonia region, marine deposits were also described on požeška gora mt., interbedded with a tuff layer and dated to 15.34 ma (brlek et al., 2020). this age suggests that the marine environment in the central part of the ncb also existed during the early badenian sensu hohenegger et al. (2014). 5.3. timing of the initial marine transgression in the ncb the results of radioisotope dating of tuffs integrated with the results of calcareous nannoplankton, foraminifera, ostracods and palynomorph assemblages from the immediately underlying and overlying beds of the tuffs at four localities in the ncb area showed that tuffs older than about 15 ma were deposited in a lacustrine freshwater environment (jovac) and in a lacustrine freshwater/brackish water environment (laz), while tuffs younger than 15 ma were deposited in a marine environment (čučerje and nježić). these results suggest that the ncb area became part of the marine realm of central paratethys about 15 ma ago, i.e. in the early badenian sensu kováč et al. (2018a), or at the transition from the early to the middle badenian sensu hohenegger et al. (2014). determination of the calcareous nannoplankton zone nn5 at the nježić and čučerje localities and the m6 orbulina suturalis (wade et al., 2011) zone and mmi4c to mmi5 (lirer et al., 2019) at the nježić locality, respectively, confirm the results of radioisotope dating (fig. 8). these results are consistent with the results of the studies on the onset of marine transgression in the ncb based on biostratigraphy ćorić et al., 2009. in particular, they concluded that the onset of the marine transgression was at least one million years later than 16 ma, which was the prevailing opinion at that time. this early badenian sensu kováč et al. (2018a) or middle badenian sensu hohenegger et al. (2014) marine transgression could be related to the tb 2.4 cycle and their deposits are described in slovenj gradec basin, styrian basin and novohrad basin (hohenegger et al., 2014; ivančič et al., 2018; hudáčková et al., 2020; ruman et al., 2021). alternatively, premec fućek et al. (2017) determined the globigerinoides trilobus zone in wells from the sava depression in the southern part of the ncb, suggesting that the initial marine flooding corresponds to the tb 2.3 3rd order sequence. the same initial marine flooding indicates marine sediments underlying and overlying tuff beds dated to 15.35 ma in the northern margin of the sava depression (brlek et al., 2020). this flooding could be the result of a marine transgression from the mediterranean towards the central paratethys domain trough dinaride gateway in present-day slovenia (kováč et al., 2018a; mandic et al., 2019a). during this period, (early badenian; upper part of nn4), the sediments of the modrý kameň fm. were deposited in the western carpathians novohrad basin (kováč et al., 2018; hudáčková et al., 2020; ruman et al., 2021), and possibly also the “schlier” of the cerová-liesková site in the vienna basin (e.g. kováč et al., 2017b). in a deep well from the central part of the sava depression hernitz kučenjak et al. (2018) determined the globigerinoides bisphericus zone, suggesting an even earlier onset of the marine transgression, corresponding to the tb 2.2 3rd order sequence. this transgression was most likely the consequence of sea-level rise and deepening gateways with the mediterranean sea through the alpine foreland (hofmayer et al., 2019) and over slovenia (ivančić et al., 2018) during the tb 2.2 cycle (sensu hardenbol et al., 1998). marine deposits associated with the tb 2.2 cycle are well described in the styrian and vienna basins in austria (hohenegger et al., 2014, harzhauser et al., 2019, 2020) and in western carpathians, novohrad basin in slovakia (ruman et al., 2021). g eologia c roatica marković et al.: middle miocene marine flooding: new 40ar/39ar age constraints with integrated biostratigraphy on tuffs from the north croatian basin 249 considering the results of this paper and those published in ćorić et al. (2009), premec fuček et al. (2017), hernitz kučenjak et al. (2018) and brlek et al. (2020), it can be assumed that different parts of the ncb were flooded at different times as a result of various marine transgression events. the central parts of the ncb in the sava depression became part of the central paratethys sea as early as the karpatian during the tb 2.2 cycle, while marginal parts of sava depression were inundated in the early badenian, during the tb 2.3 cycle. marginal parts of the ncb were terrestrial, freshwater or brackish lacustrine environments until 15 ma, when they were finally inundated during the tb 2.4 cycle. 6. conclusions tuffs from four localities in the ncb yielded the following 40ar/39ar ages: jovac (15.10 ± 0.06 ma), laz (15.42 ± 0.15 ma), čučerje (14.81 ± 0.08 ma) and nježić (14.40 ± 0.03 ma). at the jovac locality, a freshwater lacustrine environment was determined. at the laz locality, a freshwater/brackish lacustrine environment was determined. at the čučerje and nježić localities, deposition took place in a fully marine environment, in a subtropical to moderately warm climate. calcareous nannofossil data as well as planktonic foraminiferal assemblages match the data obtained by the 40ar/39ar dating method at čučerje and nježić. according to chronostratigraphic similarity, the čučerje tuff can be correlated with the demjén ignimbrite bvf eruption unit and the tuff from the nježić locality can be correlated with the harsány ignimbrite bvf eruption unit. based on the presented results, the initial marine transgression in the marginal areas of the western part of the ncb can be constrained to a period from 15.10 ± 0.06 ma to 14.81 ± 0.08 ma i.e. at the early/middle badenian boundary. considering these results with the existence of lower badenian marine sediments in the sava depression (in the southern part of ncb), it is possible to conclude that during the early badenian in the ncb freshwater lacustrine and marine environments co-existed. acknowledgement this paper presents a part of the doctoral thesis of frane marković. this work has been also supported in part by the croatian science foundation under the project ip-2019-04-7042. we are very grateful to michal kováč, imre magyar and an anonymous reviewer for their valuable and helpful reviews. many thanks to roel van elsas (vrije universiteit, amsterdam) for support with mineral separation. sem images of the ostracods were taken using the facilities of the croatian geological survey in zagreb. many thanks to marija horvat for producing the electron photomicrographs. we thank renata slavković for taking the sem images of the planktonic foraminifera. references achterberg, e.p., moore, c.m., henson, s.a., steigenberger, s., stohl, a., eckhardt, s., avendano, l.c., cassidy, m., hembury, d., klar, j.k., lucas, m.i., macey, a.i., marsay, c.m., & ryan‐keogh, t.j. (2013): natural iron fertilization by the eyjafjallajökull volcanic eruption.– geophys. res. lett., 40, 921–926, doi:10.1002/grl.50221 anthonissen, e. & ogg, j.g. (2012): appendix 3. cenozoic and cretaceous biochronology of planktonic foraminifera and calcareous nannofossils.– in: gradstein, f.m., ogg, j.g., schmitz, m.d. & ogg, g.m. (eds.): the geological time scale 2012. elsevier, amsterdan, 1083–1127. avanić, r., pavelić, d., miknić, m., brkić, m. & šimunić, a. (1995b): karpatsko-donjobadenske naslage čučerja [karpatian–lower badenian beds from čučerje – in croatian].– in: šikić, k. (ed.): geološki vodič medvednice [geo­ logical guide of mt. medvednica – in croatian].– inst. za geol. istraž. ina-industrija nafte d.d., zagreb, 156–158. avanić, r. (1997): analiza facijesa srednjeg miocena jugoistočnog dijela medvednice [facies analysis of middle miocene on southern slopes of mt. medvednica – in croatian].– unpubl. msc thesis. faculty of science, university of zagreb, zagreb, 54 p. balázs, a., matenco, l., magyar, i., horváth, f. & cloetingh, s. 2016: the link between tectonics and sedimentation in back-arc basins: new genetic constraints from the analysis of the pannonian basin.– tectonics, 35, 1526–1559. doi: 10.1002/2015tc004109 brlek, m., kutterolf, s., gaynor, s., kuiper, k., belak, m., brčić, v., holcova, k., wang, k. l., bakrač, k., hajek-tadesse, v., mišur, i., horvat, m., šuica, s. & schaltegger, u. (2020): miocene syn-rift evolution of the north croatian basin (carpathian–pannonian region): new constraints from mts. kalnik and požeska gora volcaniclastic record with regional implications.– int. j. earth sci., 109, 2775–2800. doi: 10.1007/s00531-020-01927-4 brlek, m., špišić, m., brčić, v., mišur, i., kurečić, t., miknić, m., avanić, r., vrsaljko, d. & slovenec, d. (2016): mid-miocene (badenian) transgression on mesozoic basement rocks in the mt. medvednica area of northern croatia.– facies, 62/3, 1–21. doi: 10.1007/s10347-016-0470-z cicha, i., rögl, f., rupp, c. & ctyroka, j. (1998): oligocene miocene foraminifera of the central paratethys. abhandlungen der senckenbergerschen naturforscheneiden gesellschaft, 549, 1–153. cvetković, m., matoš, b., rukavina, d., kolenković močilac, i., saftić, b., baketarić, t., baketarić, m., vuić, i., stopar, a., jarić, a. & paškov, t. (2019): geoenergy potential of the croatian part of pannonian basin: insights from the reconstruction of the pre-neogene basement unconformity.– j. maps. 15, 651–661. doi: 10.1080/17445647.2019.1645052 ćorić, s., pavelić, d., rögl, f., mandić, o., vrabac, s., avanić, r. jerković, l. & vranjković, a. (2009): revised middle miocene datum for initial marine flooding of north croatian basins (panonnian basin system, central paratethys).– geol. croat., 62/1, 31–43. doi: 10.4154/gc.2009.03 ćorić, s. & hohenegger, j. (2008): quantitative analyses of calcareous nannoplankton assemblages from the baden-sooss section (middle miocene of vienna basin, austria).– geol. carpath., 59/5, 447–460. de leeuw, a., mandic, o., vranjković, a., pavelić, d., harzhauser, m., krijgsman, w. & kuiper, k.f. (2010): chronology and integrated stratigraphy of the miocene sinj basin (dinaride lake system, croatia).– palaeogeogr. palaeoclimatol. palaeoecol., 292, 155–167. doi: 10.1016/j.palaeo.2010.03.040 de leeuw, a., mandic, o., krijgsman, w., kuiper, k. & hrvatović, h. (2012): paleomagnetic and geochronologic constraints on the geodynamic evolution of the central dinarides.– tectonophysics, 530/531, 286–298. doi: 10.1016/j. tecto.2012.01.004 de leeuw, a., filipescu, s., matenco, l., krijgsman, w., kuiper, k. & stoica, m. (2013): paleomagnetic and chronostratigraphic constraints on the middle to late miocene evolution of the transylvanian basin (romania): implications for central paratethys stratigraphy and emplacement of the tisza-dacia plate.– glob. planet. change, 103, 82–98. doi: 10.1016/j.gloplacha.2012.04.008 de verteuil, l. & norris, g. (1996): middle to upper miocene geonettia clineae, an opportunistic coastal embayment dinoflagellate of the homotryblium complex.– micropaleontology, 42, 263–284. doi: 10.2307/1485875 dybkjær, k. (2004): morphological and abundance variations in homotryblium-cyst assemblages related to depositional environments; uppermost oligocene–lower miocene, jylland, denmark.– palaeogeogr. palaeoclimatol. palaeoecol., 206, 41–58. doi: 10.1016/j.palaeo.2003.12.021 frenzel, p., keyser, d. & viehberg, f.a. (2010): an illustrated key and (palaeo) ecological primer for postglacial to recent ostracoda (crustacea) of the baltic sea. boreas, 39/3, 567–575. doi: 10.1111/j.1502-3885.2009.00135.x fodor l., jelen b., márton e., skaberne d., čar j. & vrabec m. (1998): miocene-pliocene tectonic evolution of the slovenian periadriatic fault: implications for alpine-carpathian extrusion models.– tectonics 17/5, 690–709. doi: 10.1029/98tc01605 fuhrmann, r. (2012): atlas quartärer und rezenter ostrakoden mitteldeutschlands.– mauritianum, altenburg, 320 p. gorjanović-kramberger, d. (1923): der bruchrand des zagreber gebirges zwischen podsused und zagreb und seine bedeutung zur heranbildung der zagreber terasse.– glasnik hrvatskog prirodoslovnog društva, zagreb, 34, 3–15. hajek-tadesse, v. (2006). miocene ostracods of northern croatia [in croatian with english abstract].– unpubl. ph.d. thesis, faculty of science, university of zagreb, zagreb,179 p. hajek-tadesse, v., belak, m., sremac, j., vrsaljko, d. & wacha, l. (2009): early miocene ostracods from the sadovi section (mt požeška gora, croatia).– geol. carpath., 60/3, 251–262. doi: 10.2478/v10096-009-0017-0 g eo lo gi a c ro at ic a geologia croatica 74/3250 kochansky-devidé, v. (1944): fauna marinskog miocena južnog pobočja medvednice (zagrebačke gore) [fauna of marine miocene of southern flanks of mt. med­ vednica (mt. zagrebačka) – in croatian].– vjestnik hrv. drž. geol. zav. i hrv. drž. geol. muz., 2-3, 171–280, zagreb. kochansky-devidé, v. (1956): o fauni marinskog miocena i o tortonskom „šliru“ medvednice (zagrebačka gora) [on the marine miocene fauna and the tortonian “schlier” from mt. medvednica (mt. zagrebačka) – in croatian].– geol. vjesnik, 10, 39–50. kochansky-devidé, v. (1979): srednjomiocenske kongerijske naslage požeške gore [middle miocene congeria–beds of mt. požeška – in croatian].– geol. vjesnik, 31, 69–72. koppers, a. a. p. (2002): ararcalc – software for 40ar/39ar age calculations.– comput. geosci., 28, 605–619. doi: 10.1016/s0098-3004(01)00095-4 kováč, m., andreyeva-grigorovich, a., bajraktarević, z., brzobohatý, r., filipescu, s., fodor, l., harzhauser, m., nagymarosy, a., oszczypko, n., pavelić, d., rögl, f., saftić, b., sliva, l. & studencka, b. (2007): badenian evolution of the central paratethys sea: paleogeography, climate and eustatic sea level changes.– geol. carpath., 58/6, 579–606. kováč, m., hudáčková, n., halásová, e., kováčová, m., holcová, k., oszczypko-clowes, m., báldi, k., less, g., nagymarosy, a., ruman, a., klučiar, t. & jamrich, m. (2017a): the central paratethys palaeoceanography: a water circulation model based on microfossil proxies, climate, and changes of depositional environment.– acta geol. slovaca, 9/2, 75–114. kováč, m., márton, e., oszczypko, n., vojtko, r., hók, j., králiková, s., plašienka, d., klučiar, t., hudáčková, n. & oszczypkoclowes, m., (2017b): neogene palaeogeography and basin evolution of the western carpathians, northern pannonian domain and adjoining areas.– glob. planet. change, 155, 133–154. doi: 10.1016/j.gloplacha.2017.07.004 kováč, m, halásova, e., hudáčková, n., holcová, k., hyžný, m., jamrich, m. & ruman, a. (2018a): towards better correlation of the central paratethys regional time scale with the standard geological time scale of the miocene epoch.– geologia carpathica, 69, 3, 283–300. kováč, m., márton, e., klučiar, t. & vojtko, r. (2018b): miocene basin opening in relation to the north-eastward tectonic extrusion of the alcapa megaunit.– geol. carpath, 69, 3, 254–263. doi: 10.1515/geoca-2018-0015 kovačić, m., marković, f., ćorić, s., pezelj, đ., hernitz-kučenjak, m., premec-fućek, v. & balen, d. (2015a): geological section nježić badenian marine sediments with tuff.– in: horvat, m. & galović, l. (eds.): excursion guide book. 5th croatian geological congress, osijek. croatian geological survey, zagreb, 44–47. krizmanić, k. (1995): palynology of the miocene bentonite from gornja jelenska (mount moslavačka gora, croatia).– geol. croat., 48/2, 147–154. krkalo, e. & mutić, r. (1978): tufovi u naslagama donjeg tortona u području nježića kod slavonske požege [tuffs in lower tortonian deposits of nježić area near slavonska požega, north croatia – in croatian with an english abstract].– geol. vjesnik, 30, 341–350. kuiper, k.f., deino, a., hilgen, f.j., krijgsman, w., renne, p.r. & wijbrans, j.r. (2008): synchronizing rock clocks of earth history.– science, 320, 500–504. doi: 10.1126/science.1154339 lee, j.-y., marti, k., severinghaus, j.p., kawamura, k., yoo, h.-s., lee, j.b. & kim, j.s. (2006): a redetermination of the isotopic abundance of atmospheric ar.– geochim. cosmochim. acta, 70, 4507-4512. doi: 10.1016/j. gca.2006.06.1563 lirer, f., foresi, l.m., iaccarino, s.m., salvatorini, g., turco, e., cosentino, c., sierro, f. j. & caruso, a. (2019): mediterranean neogene planktonic foraminifer biozonation and biochronology.– earth-science reviews. 196, 1–36. doi: 10.1016/j.earscirev.2019.05.013 loeblich, a.r. & tappan, h. (1988a): foraminiferal genera and their classification. – van nostrand reinhold, new york, 970 p. doi: 10.1007/978-1-4899-5760-3 loeblich, a.r. & tappan, h. (1988b): foraminiferal genera and their classification. plates.– van nostrand reinhold, new york, 1059 p. lukács, r., harangi, s., bachmann, o., guillong, m., danišík, m., buret, y., von quadt, a., dunkl, i., fodor, l., sliwinski, j., soós, i. & szepesi, j. (2015): zircon geochronology and geochemistry to constrain the youngest eruption events and magma evolution of the mid-miocene ignimbrite flare-up in the pannonian basin, eastern central europe.– contrib. mineral. petrol.,170, 52. doi: 10.1007/s00410-015-1206-8 lukács, r., harangi, s., guillong, m., bachmann, o., fodor, l., buret, y., dunkl, i., sliwinski, j., von quadt, a., peytcheva, i. & zimmerer, m. (2018): early to mid-miocene syn-extensional massive silicic volcanism in the pannonian basin (east-central europe): eruption chronology, correlation potential and geodynamic implications.– earth sci. reviews,179, 1–19. doi: 10.1016/j.earscirev.2018.02.005 magyar, i., geary, d.h. & müller, p. (1999): paleogeographic evolution of the late miocene lake pannon in central europe.– palaeogeogr. palaeoclimatol. palaeoecol., 147, 151–167. doi: 10.1016/s0031-0182(98)00155-2 hajek-tadesse, v. & prtoljan, b. (2011): badenian ostracoda from the pokupsko area (banovina, croatia).– geol. carpath., 62/5, 447–461. doi: 10.2478/v10096011-0032-9 hajek-tadesse, v., bakrač, k., mandic, o. & kovačić, m. (2016): lacustrine karpatian to lowermost badenian ostracods and palynomorphs from sjeničak section (croatia).– rcmns interim colloquium – lake basin evolution 2016., zagreb, 26–27. handler, r., ebner, f. neubauer, f., bojar, a.v. & hermann, s. (2006): 40ar/39ar dating of miocene tuffs from the styrian part of the pannonian basin: an attempt to refine the basin stratigraphy.– geol. carpath., 57/6, 483–494. hardenbol, j., thierry, j., farley, m.b., jacquin, t., de graciansky, p.-c. & vail, p.r. (1998): mesozoic and cenozoic sequence chronostratigraphic framework of european basins.– in: de graciansky p.-c., hardenbol j., jacquin t. & vail p.r. (eds.): mesozoic and cenozoic sequence stratigraphy of european basins. sepm spec. publ., 60, 3–13. doi: 10.2110/pec.98.02.0003 harzhauser, m. & piller, w.e. (2007): benchmark data of a changing sea – palaeogeography, palaeobiogeography and events in the central paratethys during the miocene).– palaeogeogr. palaeoclimatol. palaeoecol., 253, 8–31. doi: 10.1016/j. palaeo.2007.03.031 hernitz kučenjak m., premec fućek v., krizmanić, k., tadej, j., zlatar, s. & matošević, m. (2018): karpatian and badenian transgressions in croatian part of the pannonian basin system (biostratigraphy and palaeoenvironments).– forams 2018. temporary abstract collection, edinburgh, 273–274. harzhauser, m., theobalt, d., strauss, p., mandic, o. & piller, werner e. (2019): seismic-based lower and middle miocene stratigraphy in the northwestern vienna basin (austria).– newsletters on stratigraphy, 52, 2, 221–247. doi: 10.1127/nos/2018/0490 harzhauser, m., kranner, m., mandic, o., strauss, p., siedl, w. & piller, werner e. (2020): miocene lithostratigraphy of the northern and central vienna basin (austria).– austrian journal of earth sciences, 113, 2, 169–199. doi: 10.17738/ajes.2020.0011 hernitz kučenjak m., premec fućek v., krizmanić, k., tadej, j., zlatar, s. & matošević, m. (2018): karpatian and badenian transgressions in croatian part of the pannonian basin system (biostratigraphy and palaeoenvironments).– forams 2018. temporary abstract collection, edinburgh, 273–274. hofmayer, f., kirscher, u., sant, k., krijgsman, w., fritzer, t., jung, d., weissbrodt, v. & reichenbacher, b. (2019): three-dimensional geological modeling supports a revised burdigalian chronostratigraphy in the north alpine foreland basin.– int. j. earth sci., 108, 2627–2651. doi: 10.1007/s00531019-01780-0 hohenegger, j., ćorić, s. & wagreich, m. (2014): timing of the middle miocene badenian stage of the central paratethys.– geol. carpath., 65/1, 55–66. doi: 10.2478/geoca-2014-0004 horváth, f., bada, g., szafián, p., tari, g., ádám, a. & cloetingh,s. (2006): formation and de-formation of the pannonian basin: constraints from observational data.– geol. soc. lond. mem., 32/1, 191–206. doi: 10.1144/gsl. mem.2006.032.01.11 horváth, f. & tari, g. (1999): ibs pannonian basin project: a review of the main results and their bearings on hydrocarbon exploration.– geol. soc., lond., spec. publ., 156, 195–213. doi: 10.1144/gsl.sp.1999.156.01.11 hudáčková, n., holcová, k., halásová, k., kováčová, m., doláková, n., trubač, j., rybár, s., ruman, a., stárek, d., šujan, m., jamrich, m. & kováč, m. (2020): the pannonian basin system northern margin paleogeography, climate, and depositional environments in the time range during mmct (central paratethys, novohrad-nógrád basin, slovakia).– palaeon­ tologia electronica, 23/3, 50. doi: https://doi.org/10.26879/1067 iaccarino, s. m., di stefano, a., foresi, l. m., turco, e., baldassini, n., cascella, a., da prato, s., ferraro, l., gennari, r., hilgen, f. j., lirer, f., maniscalco, r., mazzei, r., riforgiato, f., russo, b., sagnotti, l., salvatorini, g., speranza, f. & veducci, m. (2011): high-resolution integrated stratigraphy of the mediterranean langhian: comparison with the historical stratotype and new perspectives for the gssp. stratigraphy, 8/2–3, 199–215. ivančič, k., trajanova, m., ćorić, s., rožič, b. & šmuc, a. (2018): miocene paleogeography and biostratigraphy of the slovenj gradec basin: a marine corridor between the mediterranean and central paratethys.– geol. carpath., 69, 6, 528–544, doi: 10.1515/geoca-2018-0031 jamičić, d. (1988): strukturni sklop slavonskih planina (sjeverni psunj, papuk, krndija) [structural fabric of the slavonian mts. (northern psunj, papuk, krndija) – in croatian].– unpubl. phd thesis, university of zagreb, 152 p. jamičić, d., brkić, m.,crnko, j. & vragović, m. (1987): osnovna geološka karta sfrj 1:100.000, tumač za list orahovica l33-96 [basic geologic map of sfry 1:100000, geology of the orahovica sheet – in croatian].– geološki zavod, zagreb, savezni geološki institut, beograd, 72 p. jamičić, d. (1995): the role of sinistral strike-slip faults in the formation of the structural fabric of the slavonian mts. (eastern croatia).– geol. croat., 48, 155–160. g eologia c roatica marković et al.: middle miocene marine flooding: new 40ar/39ar age constraints with integrated biostratigraphy on tuffs from the north croatian basin 251 mandic, o., de leeuw, a., vuković, b., krijgsman, w., harzhauser, m. & kuiper, k.f. (2011) palaeoenvironmental evolution of lake gacko (southern bosnia and herzegovina): impact of the middle miocene climatic optimum on the dinaride lake system.– palaeogeogr. palaeoclimatol. palaeoecol., 299, 475– 492. doi: 10.1016/j.palaeo.2010.11.024 mandic, o., de leeuw, a., bulić, j., kuiper, k., krijgsman, w. & jurišićpolšak, z. (2012): paleogeographic evolution of the southern pannonian basin: 40ar/39ar age constraints on the miocene continental series of northern croatia.– int. j. earth sci., 101, 1033–1046. doi: 10.1007/s00531-011-0695-6 mandic, o., kurečić, t., neubauer, t.a. & harzhauser, m. (2015): stratigraphic and paleogeographic significance of lacustrine mollusks from the pliocene viviparus beds in central croatia.– geol. croat., 68, 179–207. doi: 10.4154/ gc.2015.15 mandic, o., hajek-tadesse, v., bakrač, k., reichenbacher, b., grizelj, a. & miknić, m. (2019a): multiproxy reconstruction of the middle miocene požega palaeolake in the southern pannonian basin (ne croatia) prior to the badenian transgression of the central paratethys sea.– palaeogeogr. palaeoclimatol. palaeoecol., 516, 203–219. doi: 10.1016/j.palaeo.2018.12.003 martini, e. (1971): standard tertiary and quaternary calcareous nannoplankton zonation.– in: farinacci, a. (ed.): proceedings of the 2 plankt. conf., roma, 739–785. martinuš, m., fio, k., pikelj, k. & aščić, š. (2013): middle miocene warmtemperate carbonates of central paratethys (mt. zrinska gora, croatia): paleoenvironmental reconstruction based on bryozoans, coralline red algae, foraminifera, and calcareous nannoplankton.– facies, 59, 481–504. doi: 10.1007/s10347-0120327-z márton, e., pavelić, d., tomljenović, b., pamić, j. & márton, p. (1999): first paleomagnetic results on tertiary rocks from the slavonian mountains in the southern pannonian basin, croatia.– geol. carpath., 50, 273–279. márton, e., pavelić, d., tomljenović, b., avanić, r., pamić, j. & márton, p. (2002): in the wake of a counterclockwise rotating adriatic microplate: neogene paleomagnetic results from northern croatia.– int. j. earth sci., 91, 514–523. doi: 10.1007/s00531-001-0249-4 matenco, l. & radivojević, d. (2012): on the formation and evolution of the pannonian basin: constraints derived from the structure of the junction area between the carpathians and dinarides.– tectonics, 31, tc6007. doi: 10.1029/2012tc003206 mcdougall, i. & harrison, t.m., (1999): geochronology and thermochrono logy by the 40ar/39ar method. oxford university press, new york, 269 p. meisch, c. (2000): freshwater ostracoda of western and central europe.– spektrum akademischer verlag, heidelberg, berlin, 522 p. mészáros, n. & şuraru, n. (1991): le nannoplancton et les foraminifères du complexe du tuf de dej de la région poimeni-pâgliţa.– in: mârza, i. (ed.): the volcanic tuffs from the transylvanian basin, romania. geological formations transylvania, romania, cluj-napoca, 3, 83–88. min, k., mundil, r., renne, p.r. & ludwig, k.r. (2000): a test for systematic errors in 40ar/39ar geochronology through comparison with u–pb analysis of a 1.1 ga rhyolite.– geochim. cosmochim. acta, 64/1, 73–98. doi: 10.1016/s00167037(99)00204-5 moore, p.d., webb, j.a., collinson, m., (1991): pollen analysis (second edition).– blackwell sci. publication. london, 216 p. mutić, r. (1969): neogenska magmatska aktivnost na jugoistočnim obroncima medvednice (zagrebačke gore) [neogene magmatic activity on the southeastern slopes of medvednica mt. (zagrebačka mt.) – in croatian].– geol. vjesnik, 22, 423–438. mutić, r. (1973): tufovi u neogenskim naslagama na sjevernim obroncima medvednice (zagrebačke gore) [tuffs in neogene deposits on the northern slopes of med­ vednica mt. (zagrebačka mt.) – in croatian].– geol. vjesnik, 25, 227–235. mutić, r. (1980): tufovi u donjohelvetskim naslagama u području brestika i bojne (banija, hrvatska) [tuffs in lower helvetian beds in the area of brestik and bojna (banija, croatia) – in croatian].– geol. vjesnik, 31, 253–266. murray, j.w. (2006): ecology and applications of benthic foraminifera. cambridge – university press, cambridge, 438 p. doi: 10.1017/cbo9780511535529 nagy, e. (1985): sporomorphs of neogene in hungary.– geologica hungarica, series palaeontologica, 47, 1–471. nagymarosy, a. & müller, p. (1988): some aspects of neogene biostratigraphy in the pannonian basin.– in: royden, l.h. & horváth, f. (eds.): the pannonian basin. a study in basin evolution. aapg mem., 45, 69–77. neubauer, t.a., harzhauser, m., kroh, a., georgopoulou, e. & mandic, o. (2015): a gastropod-based biogeographic scheme for the european neogene freshwater systems.– earth sci. reviews, 143, 98–116. doi: 10.1016/j.earscirev.2015.01.010 pamić, j. (1997): vulkanske stijene savsko-dravskog međuriječja i baranje (hrvatska) [volcanic rocks of the area between sava and drava rivers and baranja (croatia) – in croatian].– časopis nafta, zagreb, 192 p. papp, a. & schmid, m.e. (1985): the fossil foraminifera of the tertiary basin of vienna. die fossilen foraminiferen des tertiaren bekens von wien. – abh. geologisch. bundesanst., band, 37, 1– 311. papp, a., cicha, i. & čtyroká, j. (1978): foraminifera. – in: papp, a., cicha, i., seneš, j. & steininger, f. (eds.): chronostratigraphie und neostratotypen miozän der zentralen parathetys. badenian, verlag der slowak. akad. der wissen., bratislava, 263 – 325. pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.– basin research, 13, 359– 376. doi: 10.1046/j.0950-091x.2001.00155.x pavelić, d., avanić, r & zupanič, j. (2000): ottnangian lacustrine sediments on mt. medvednica: facies, depositional environments and tectonic controls (pannonian basin system (croatia).– in: vlahović, i. & biondić, r. (eds.): proceedings, second croatian geological congress, cavtat-dubrovnik, 17-20.5.2000., zagreb, 339–343. pavelić, d., avanić, r., kovačić, m., vrsaljko, d. & miknić, m. (2003): an outline of the evolution of the croatian part of the pannonian basin system.– in: vlahović, i. &. & tišljar, j. (eds.): evolution of depositional environments from the palaeozoic to the quaternary in the karst dinarides and the pannonian basin. 22nd ias meeting of sedimentology, opatija, field trip guidebook, 155–161. pavelić, d. & kovačić, m. (2018): sedimentology and stratigraphy of the neogene rift-type north croatian basin (pannonian basin system, croatia): a review.– mar. pet. geol., 91, 455–469. doi: 10.1016/j.marpetgeo.2018.01.026 perch-nielsen, k. (1985). mesozoic calcareous nannofossils.– in: bolli, h.m., saundes, j.b. & perch-nielsen, k. (eds.): plankton stratigraphy. cambridge university press, cambridge, 427–554. pezelj, đ. & drobnjak, l. (2019): foraminifera-based estimation of water depth in epicontinental seas: badenian deposits from glavnica gornja (medvednica mt., croatia), central paratethys.– geol. croat., 72/2, 5–18. doi: 10.4154/gc.2019.08 pezelj, ð., mandic, o. & ćorić, s. (2013): paleoenvironmental dynamics in the southern pannonian basin during initial middle miocene marine flooding.– geol. carpath., 64, 81–100. piller, w.e., harzhauser, m., & mandic, o. (2007): miocene central paratethys stratigraphy current status and future directions.– stratigraphy, 4, 151–168. popov, s.v., rögl, f., rozanov, a.y., steininger, f. f., shcherba, i.g. & kovác, m. (2004): lithological-paleogeographic maps of paratethys. 10 maps late eocene to pliocene.– courier forschungsinstitut senckenberg, 250, 1–46. premec fućek, v., hernitz kučenjak, m., krizmanić, k. tadej, j. & zlatar, s. (2017): controversies on karpatian and badenian transgressions in croatian part of the pannonian basin system (biostratigraphy and palaeoenvironments).– in: horvat, m. & wacha, l. (eds.): abstract volume seventh international workshop, neogeon of central and south-eastern europe, velika, croatia: croatian geological society, zagreb, 50–51. raffi, i., wade, b.s. & pälike, h. (2020): the neogene period. -in: gradstein, f.m., ogg, j.g., schmitz, m.d. & ogg, g.m. (eds.): geological time scale 2020. elsevier, amsterdam, 1141–1215. rögl, f. (1996a): migration pathways between africa and eurasia. oligocene-miocene paleogeography.– europal., 10, 23–26. rögl, f. (1996b): stratigraphic correlation of the paratethys oligocene and miocene.– mitt. ges. bergbaustud. österr, 41, 65–73. rögl, f. (1999): mediterranean and paratethys, facts and hypotheses of an oligocene to miocene paleogeography (short overview).– geol. carpath., 50/4, 339–349. rögl, f. & steininger, f.f. (1983): vom zerfall der tethys zu mediterran und paratethys. die neogene palaeogeographie und palinspastik des zirkum-mediterranen raumes.– annalen des naturhistorischen museums, wien, 85/a, 135–163. rögl, f. & steininger, f.f. (1984): neogene paratethys, mediterranean and indopacific seaways.– in: brenchley, p. (ed.): fossils and climate, john wiley & sons, new york, 171–200. royden, l.h. (1988): late cenozoic tectonics of the pannonian basin system.– in: royden, l.h. & horváth, f. (eds.): the pannonian basin. a study in basin evolution.– aapg mem., 45, 27–48. ruman, a., ćorić, s., halásová, e., harzhauser, m., hudáčková, n., jamrich, m., palzer-khomenko, m., kranner, m., mandic, o., rybár, s., šimo, v., šujan, m. & kováč, m. (2021): the “rzehakia beds” on the northern shelf of the pannonian basin: biostratigraphic and palaeoenvironmental implications.– facies, 67/1. doi: 10.1007/s10347-020-00609-6 saftić, b., velić, j., sztanó, o., juhász, g. & ivković, ž. (2003): tertiary subsurface facies, source rocks and hydrocarbon reservoirs in the sw part of the pannonian basin (northern croatia and south western hungary).– geol. croat., 56/1, 101–122. sant, k., palcu, d. v., mandic, o. & krijgsman, w. (2017): changing seas in the early-middle miocene of central europe: a mediterranean approach to paratethyan stratigraphy.– terra nova, 29, 273–281. doi: 10.1111/ter.12273 sant, k., mandic, o., rundić, l., kuiper, k. f. & krijgsman, w. (2018): age and evolution of the serbian lake system: integrated results from middle miocene lake popovac.– newsl. stratigr., 51, 117–143. doi: 10.1127/nos/2016/0360 sant, k., palcu, d.v., turco, e., di stefano, a., baldassini, n., kouwenhoven, t., kuiper, k.f., & krijgsman, w. (2019): the mid-langhian floodg eo lo gi a c ro at ic a geologia croatica 74/3252 ing in the eastern central paratethys: integrated stratigraphic data from the transylvanian basin and se carpathian foredeep.– int. j. earth sci., 108, 2209–2232. doi: 10.1007/s00531-019-01757-z sant, k., kuiper, k.f., rybar, s., grunert, p., harzhauser, m., mandic, o., jamrich, m., sarinova, k., hudackova, n. & krijgsman, w. (2020): ar-40/ar-39 geochronology using high sensitivity mass spectrometry: examples from middle miocene horizons of the central paratethys.– geol. carpath., 71, 166–182. doi: 10.31577/geolcarp.71.2.5 schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpinecarpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss j. geosci., 101, 139–183. doi: 10.1007/s00015-008-1247-3 sokač, a. (1987): pannoninotus n. gen. (crustacea, ostracoda) from the middle miocene of bjelanovac (psunj mountain, north croatia).– geol. vjesnik, 40, 39–44. steininger, f., rögl, f. & martini, e. (1976): current oligocene-miocene biostratigraphic concept of the central paratethys (middle europe).– newsl. stratigr., 4, 174–202. steininger, f.f., müller, c. & rögl, f. (1988): correlation of central paratethys, eastern paratethys and mediterranean neogene stages.– in: royden, l.h. & horváth, f. (eds.): the pannonian basin. a study in basin evolution. aapg mem., 45, 79–87. szakács, a., pécskay, z. & gál, á. (2018): patterns and trends of time-space evolution of neogene volcanism in the carpathian-pannonian region: a review.– acta geod. et geophys., 53, 347–367. doi: 10.1007/s40328-018-0230-3 šćavničar, s., krkalo, e., šćavničar, b., halle, r. & tibljaš, d. (1983): naslage s analcimom u poljanskoj [analcime bearing deposits in poljanska, sla­ vonia, northern croatia – in croatian].– rad jazu, 404, 137–169. šikić, l. (1968): stratigrafija miocena sjeveroistočnog dijela medvednice na osnovu faune foraminifera [stratigraphy of the miocene on basis of foraminiferal fauna – in croatian].– geol. vjesnik, 21, 213–227. tomljenović, b. & csontos, l. (2001): neogene–quaternary structures in the border zone between alps, dinarides and pannonian basin (hrvatsko zagorje and karlovac basins, croatia).– int. j. earth sci, 90, 560–578. doi: 10.1007/ s005310000176 ustaszewski, k., herak, m., tomljenović, b., herak, d. & matej, s. (2014): neotectonics of the dinarides-pannonian basin transition and possible earthquake sources in the banja luka epicentral area.– j. geodyn., 82, 52–68. doi: 10.1016/j.jog.2014.04.006 van morkhoven f.p.c.m. (1963): post-palaeozoic ostracoda. their morphology, taxonomy and economic use. vol. ii. generic descriptions.– elsevier publ. co., amsterdam/london/new york, 1–478. vesel lukić, m. & hajek-tadesse, v. (2017): badenian ostracods from požeška gora and papuk mts.– in: horvat, m. & wacha, l. (eds.): 7th international workshop neogene of central and south–eastern europe, zagreb: croatian geological society, 2017, 73–74. wade, b.s., pearson, p. n., berggren, w. a. & pälike, h. (2011): review and revision of cenozoic planktonic foraminiferal biostratigraphy and calibration to the geomagnetic polarity and astronomical time scale.– earth sci. reviews, 104, 111–142. doi: 10.1016/j.earscirev.2010.09.003 wood, g.d., gabriel, a.m. & lawson, j.c. (1996): palynological techniques: processing and microscopy.– in: jansonius, j. & mcgregor, d.c. (eds.): palynology: principles and applications. am. assoc. stratigr. palynol. found., 1, 29–50. young, j.r., wade, b.s. & huber, b.t. (2020, eds): pforams@mikrotax website.– 4th march 2020. url: http://www.mikrotax.org/pforams žagar-sakač, a. (2004): the ottnangian unionaceae from jelov dol.– nat. croat., 3/2, 225–252. zonneveld, k.a.f. & pospelova, v. (2015): a determination key for modern dinoflagellate cysts.– palynology 39/3, 387–407. doi: 10.1080/01916122.2014.990115 www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2025 | 78/2 | 173–183 | 5 figs. | 1 tab. | 1. introduction the lack of subsurface data and the inherent subjectivity of interpreters have been major contributors to imprecise or overly simplified interpretations and resulting geological models. well data are often too sparse to enable meaningful interpretations using traditional methods, so the implementation of seismic data with advanced machine learning techniques is expected to yield better modelling results (smirnoff et al., 2008; zhou et al., 2019; feng et al., 2024; zhou & liu, 2024). machine learning techniques enable the combination of well and seismic derived properties in a time efficient way which can greatly improve the accuracy and the resolution of the resulting geological model. visualizing subsurface lithology, including the volume and spatial distribution of rock types, typically starts with well data. this generally refers to well logs and information about the lithology of well cuttings and core samples if available. however, in many regions worldwide, the number of wells is shale volume, seismic attributes, and proper data preparation: critical components for modelling subsurface lithology distribution ana kamenski1, iva kolenković močilac2,*, marko cvetković2 1 croatian geological survey, sachsova 2, 10000 zagreb croatia; (akamenski@hgi-cgs.hr) 2 faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, 10000 zagreb, croatia; (*corresponding author: iva.kolenkovic@rgn.unizg.hr; marko.cvetkovic@rgn.unizg.hr) doi: 10.4154/gc.2025.12 abstract the scarcity of well data and the inherent subjectivity of geological interpretations often leads to imprecise or oversimplified subsurface models. traditional interpretation methods struggle with sparse datasets, necessitating the application of advanced machine learning techniques to enhance subsurface characterization. this study leverages artificial neural networks to predict lithology distribution using seismic attributes in the northern croatian part of the pannonian basin system, an area with numerous exploratory wells. seismic data, long employed as a supplementary interpretation tool, was used to generate a predictive lithological model, overcoming data limitations inherent to well-based methods. a key focus was the volume of shale, a lithological indicator, which was estimated using an extensive set of seismic attributes and processed through innovative data preparation techniques for artificial neural network analysis. a comprehensive artificial neural network based modelling approach was implemented over a 4365 km² 3d seismic dataset, targeting pannonian (late miocene–early pliocene) sediments deposited in deltaic, turbiditic, and lacustrine environments. results show that standardization of input data significantly improved model accuracy, particularly in capturing key geological features such as meandering sandstone-filled channels. in contrast, normalization led to unreliable predictions, while raw data substantially underestimated sandstone volumes. despite its advantages, the method’s limitations stem from the inherent uncertainty in the volume of shale estimation and interpreter subjectivity. the approach is well-suited for geological settings with two or three dominant lithologies distinguishable on geophysical well logs. while applicable to coalbearing strata and shale-rich carbonates, its effectiveness in more complex geological settings requires further refinement. the findings highlight the untapped potential of legacy seismic data for geo-energy applications, including hydrocarbon exploration, geothermal studies, and carbon storage. limited, they are either sparsely distributed, or the available data is old. the croatian part of the pannonian basin system is characterized by a several hundred, old exploratory wells, some of which were drilled over 50 years ago. therefore, seismic data has long been used as a supplementary tool to aid the geological interpretation process, offering valuable insights into subsurface characterization (novak zelenika et al., 2018; vukadin, 2022; xu & haq, 2022). in recent years, this type of study has increasingly relied on the application of artificial neural networks for various purposes: lithology prediction (brcković et al., 2017; kamenski et al., 2020), estimation of porosity and permeability (iturraránviveros & parra, 2014), seismic reservoir characterization (othman et al., 2021), shale volume prediction (taheri et al., 2021; mohammadinia et al., 2023), two-way-time prediction (kamenski et al., 2024). recent studies in northern croatia, specifically within the southwestern part of the pannonian basin system, have article history: manuscript received: february 10, 2025 revised manuscript accepted: march 25, 2025 available online: april 28, 2025 keywords: volume of shale, artificial neural networks, lithology mapping, geo-energy exploration mailto:akamenski@hgi-cgs.hr mailto:iva.kolenkovic@rgn.unizg.hr g eo lo gi a c ro at ic a 174 geologia croatica 78/2 explored the application of neural networks to enhance the independence and accuracy of subsurface interpretations based on various geophysical datasets (seismics, well logs), in combination with well data (brcković et al., 2017; kamenski et al., 2020; kamenski et al., 2024). these studies demonstrated the effectiveness of neural networks, particularly in scenarios with limited data. for instance, the inevitable challenges of time-to-depth conversions were successfully surpassed using neural networks, which predicted two-way-time data from stratigraphical and petrophysical parameters in the depth domain, particularly in scenarios where conventional time-to-depth conversion data were unavailable (kamenski et al., 2024). efforts have also been made to predict lithology based on sparse well and seismic data (brcković et al., 2017; kamenski et al., 2020). these investigations provided valuable new insights into subsurface characterization in northern croatia, while also highlighting challenges of lithology prediction, such as the inadequate upscaling of well logs (kamenski et al., 2020). to determine the lithology distribution in areas where only seismic data is available and well data is sparse, this study utilized an extensive set of seismic attributes to predict the volume of shale, a parameter that serves as an indicator of lithology distribution. furthermore, this approach was tested with legacy data, as pre-stack seismic data, which can be utilized for lithology prediction, is often unavailable (adeoti et al., 2017; bornard et al., 2005). to achieve this, innovative data preparation processes were implemented. this study highlights the successful application of available legacy data, revealing its substantial untapped potential that has yet to be fully utilized when processed by artificial neural network algorithms. neural networks were chosen for lithology distribution prediction over other machine learning approaches for several key reasons. primarily, neural networks represent an excellent tool for capturing complex, non-linear relationships inherent in geological data, which makes them well-suited for modelling intricate subsurface patterns. additionally, they have proven successful in similar applications, such as predicting porosity and permeability (e.g., iturrarán-viveros & parra, 2014), further validating their effectiveness in geoscientific tasks. to demonstrate this approach, a study area with available 3d seismic data, covering 4365 km2 in the northern part of croatia was selected (fig. 1) to investigate the possibility of predicting the general lithology distribution within the pannonian stratigraphic interval based on seismic attributes. results from this study can have application in geoenergy characterization for various purposes, from hydrocarbon exploration, geothermal investigations, carbon capture, utilization and storage, etc. 2. geological overview the study area, located in the north croatian basin (ncb), lies within the southwestern part of the pannonian basin system (pbs). base of the neogene-quaternary infill is represented by palaeozoic crystalline and partially meta morphosed rocks, which are in places overlain by mesozoic carbonates (pamić & lanphere, 1991; pamić, 1998; pavelić, 2001; velić, 2007; malvić & cvetković, 2013; pavelić & kovačić, 2018). basin evolution is associated with rifting, and syn-rift and post-rift sediments can be distinguished (lučić et al., 2001; saftić et al., 2003; pavelić & kovačić, 2018; rukavina et al., 2023). the extension began during the ottnangian and carpathian and is believed to have been driven by the eastward extrusion of the alps (fodor et al., 1999). in these conditions, deposition of coarse-grained sediments (rock-fall breccias and conglomerates) interlayered with sandy and silty layers took place (pavelić & kovačić, 2018). the extension was accompanied by a later marine transgression and volcanic activity in the badenian (lučić et al., 2001; saftić et al., 2003; ćorić et al., 2009; marković et al., 2021). depositional environments during the badenian were very diverse. locally, marsh-type fine-grained sediments can be found, which are overlain by carbonate deposits (bakrač et al., 2010). deepening of the depositional environment resulted in the lacustrine sedimentation of shales, and siltstones, together with thin, sandy turbidites and occasional conglomerates (pavelić & kovačić, 2018), with sporadic occurrences of pyroclastics resulting from accompanying volcanism (pavelić, 2001; saftić et al., 2003). a change of depo sitional environment from lacustrine to marine occurred during the middle badenian with deposition of shales interlayered with coarse grained clastics (pavelić & kovačić, 2018). the late badenian is characterized by the end of the syn-rift phase and the beginning of the post-rift phase (pavelić, 2001; pavelić & kovačić, 2018). during the late badenian, carbonate sedimentation on small carbonate platforms, formed around islands, was followed by marl deposition in the deeper parts of the sea (vrsaljko et al., 2006; pavelić & kovačić, 2018). by the latest badenian, a general shallowing occurred, marked by deposition of biocalcarenites and conglomerates, reduced volcanic activity, and localized emersions. the breakup of central paratethys started in the latest badenian when it lost connection to the indo-pacific ocean and the palaeo-mediterranean sea (rögl, 1999). the isolation of the basin and subsequent salinity fluctuations at the badenian/ sarmatian boundary led to the extinction of most stenohaline marine organisms, while unique associations adapted to the new conditions, emerged or migrated from eastern paratethys, marking the sarmatian age of the deposits (pavelić & kovačić, 2018 and references therein). the final separation of the pannonian basin system from other surrounding marine environments took place at the end of the middle miocene (ćorić et al., 2009). the post-rift phase of pbs development was characterized by a thermal subsidence due to lithospheric cooling (pavelić & kovačić, 2018), resulting in the creation of significant accommodation space. this phase was characterized by the deposition of thick sand and marl sequences in brackish conditions within lake pannon (lučić et al., 2001; saftić et al., 2003; pavelić & kovačić, 2018). during the pliocene and quaternary, the stress regime turned to compressional, which resulted in activation of reverse faults and reactivation of normal faults with reverse displacement characteristics (horváth & cloetingh, 1996). sedimentary environments were shallower than in the pannonian with g eologia c roatica 175kamenski et al.: shale volume, seismic attributes, and proper data preparation: critical components for modelling subsurface lithology distribution f luctuations from lacustrine and marsh to terrestrial (cvetković, 2013). lithologically, they are represented by sands, clays and gravel with occasional coal seams or layers. as the tectonic regime shifted from extensional to compressional, basin inversion occurred which led to the formation of structural traps within the older pannonian sediments. the ncb’s marginal position within the pbs results in generally thinner neogene sedimentary sequences compared to the central part of the pbs, with the exception of the drava basin where the neogene sedimentary sequence reaches a thickness of almost seven kilometres (saftić et al., 2003; velić, 2007; cvetković et al., 2019). the focus of this research is the sediments of the pannonian (late miocene–early pliocene), that were deposited after the central paratethys sea transitioned into the brackish lake pannon around 11.6 million years ago. pannonian sediments, primarily derived from the eastern alps and the western carpathians, were deposited in a variety of environments, including deltaic, turbiditic, and lacustrine settings (kovačić & grizelj, 2006; pavelić & kovačić, 2018; matošević et al., 2024a). the pannonian deposits include lacustrine marls and limestones in the early stages, followed by sands and siltstones from deltaic environments as the lake progressively filled. these deposits serve as significant source rocks, reservoirs, and caprocks in the croatian part of the pbs (lučić et al., 2001; saftić et al., 2003). 3. methodology for the task of determining the spatial distribution of lithology throughout the study volume, a comprehensive workflow was implemented. this began with the definition of the model figure 1. the pannonian basin system with the outline of the north croatian basin and the study area location. the red rectangle represents the extent of 3d seismic coverage of the “donji miholjac” 3d seismic block with the locations of 11 wells highlighted, enlarged in the inset at lower right corner (modified from cvetković et al. (2019), after dolton (2006) and schmid et al. (2008)). g eo lo gi a c ro at ic a 176 geologia croatica 78/2 boundaries. the top and bottom of the model were delineated based on regional well tops identified using resistivity well logs. for this study, focusing on the sediments of the pannonian stratigraphic interval, the regional marker “α” was chosen as the model’s top surface and “rs7” as its bottom, i.e. top pannonian and base pannonian surfaces respectively. lateral boundaries were defined with the 3d seismic volume coverage. exploratory wells within the study area were very scarce, so all the wells which at least partially intersected the chosen interval were taken into the analysis. a total of 11 wells were included: eight that drilled trough both the top pannonian (“α”) and base pannonian (“rs7”) boundaries, and three which were terminated before reaching the base of the pannonian, i.e. intersecting only part of the interval of interest. the top pannonian well top (“α”) is not identified by distinct patterns in the apparent electrical resistivity curve. instead, it is defined as the transition point where the resistivity curve shifts from a shallower zone with high variability in resistivity to a deeper zone characterized by more stable resistivity values. this transition is the result of change in depositional conditions, specifically the shift from deeper-water lacustrine sedi mentation during the pannonian to shallow lacustrine and alluvial sedimentation in the pliocene of the drava basin and also in the western part of the sava basin, which is characterized by more frequent vertical and lateral lithological variations, reflected on the resistivity curve (cvetković, 2017). well top “rs7” was defined by an emphasized increase in resistivity values at the transition from the lower pannonian limey shales to the middle miocene limestone, due to pronounced resistivity differences between the limestones and shales (palacky, 1988). a well to seismic tie was performed either on the basis of available vertical seismic profiling measurements in the wells or with the artificial neural network approach as in kamenski et al. (2024). these horizons were mapped across the “donji miholjac” 3d seismic block (fig. 2), producing interpreted surfaces that defined a study area of 4,365 km² with a total volume of 11,660 km³. a volume of shale (vsh) analysis was performed by interpreting the spontaneous potential (sp) log (fig. 3), as neutron, spectral radioactivity, resistivity, and gamma ray logs were excluded from the analysis due to technological and/ or geological constraints specific to the study area. this widely used procedure (serra, 1984; asquith & krygowski, 2004) is based on the assumption that the sp deflection between the static value of sp (ssp) in a clean sandstone and shale baseline (representing 100% shale) is proportional to the volume of shale (rider, 2002), i.e. it assumes that the volume of shale at any given point can be estimated by linear interpolation between the sp value having 0% of shale (spclean) and the shale baseline value (spshale) having 100% of shale (equation 1): v sp sp sp spsh clean shale clean = ×100 (1) where sp represents reading of sp value in any point of interest. once the volume of shale (vsh) values were obtained for all 11 wells, upscaling was performed to firstly average the vsh value within the corresponding model cell and to enable integration with the seismic data. this was performed for models with 20, 50, 100 and 200 layers. based on the results and to mitigate overestimation of the predominant lithology, the selected model was the one stratified into 200 layers, maintaining an average cell height of 6.5 metres. this approach effectively prevented excessive layering thickness, ensuring that the upscaling process did not introduce biases in lithology distribution predictions by the artificial neural networks (anns). overestimation of the predominant lithology had been a significant challenge in previous studies (kamenski et al., 2020), but this refined layering strategy minimized such distortions. following the upscaling of the volume of shale (vsh) values, selected seismic attributes were extracted at the upscaled data points, forming a comprehensive dataset for ann training. this step ensured that the model retained both the geological resolution necessary for more realistic lithology prediction and the statistically valid dataset required for effective machine learning applications. seismic attributes contain a huge amount of data which holds significant relationships between the physical char acteristics that remain undetectable through conventional seismic visualization techniques (taner et al., 1976; taner, 2001). these attributes, derived from seismic data, capture kinematic, dynamic, geometric, and statistical characteristics, play a fundamental role in structural, stratigraphic, and petrophysical interpretation. their application significantly enhances subsurface analysis and reservoir characterization (djeddi, 2016). in this study, the selection of seismic attributes was guided by their ability to emphasize lithological and morphological features, thereby aiding artificial neural networks in producing geologically coherent lithology distribution predictions. seismic attributes that capture key lithological and morphological features were generated based on comprehensive reviews of seismic attribute application (chopra & marfurt, 2006; liu & marfurt, 2006; ker et al., 2014; brcković et al., 2017; li et al., 2019; oumarou et al., 2021). twelve attributes were constructed: sweetness, 3d curvature, varifigure 2. inline seismic section highlighting the interpreted top and base pannonian surfaces of the subsurface model. the inset indicates the location of the seismic section within the study area. g eologia c roatica 177kamenski et al.: shale volume, seismic attributes, and proper data preparation: critical components for modelling subsurface lithology distribution ance, original amplitude, instantaneous frequency, envelope, instantaneous phase, generalized spectral decomposition, apparent polarity, reflection intensity, root-mean-square (rms) amplitude and relative acoustic impedance. sweetness and rms amplitude effectively detect and display coarse-grained intervals and compaction features (subrahmanyam & rao, 2008; koson et al., 2014). variance (edge) and reflection intensity serve as reliable indicators of lithology variations (pigott et al., 2013; koson et al., 2014), while original amplitude provides a clear representation of sediment continuity and discontinuity (brcković et al., 2017 and references therein). additionally, apparent polarity is mostly related to the useful detection of gas-charged layers (ker et al., 2014). oumarou et al. (2021, and references therein) demonstrated that instantaneous frequency aids in seismic facies recognition, while 3d curvature is crucial for identifying structural features such as channels, faults, anticlines, synclines, and salt domes. instantaneous phase delineates subsurface layering, whereas instantaneous frequency and generalized spectral decomposition assist in layer thickness estimation and seismic geomorphology analysis (liu & marfurt, 2006; li et al., 2019). furthermore, envelope and relative acoustic impedance (rai) provide insights into lithology, thickness estimation, and sequence delineation, and offer valuable information regarding porosity and permeability (oumarou et al., 2021; pigott et al., 2013; koson et al., 2014). input data for ann analysis consisted of data points created along well paths, each containing x, y, z coordinates, 12 seismic attributes and shale volume values (fig. 4a, b). data was statistically processed before the ann training process. feature scaling was applied to mitigate the significant scale differences among seismic attributes. three input versions were prepared: raw data, normalized data (rescaled between 0 and 1), and standardized data (centered at a mean of 0 with a standard deviation of 1). normalization and standardization processes ensured uniform scaling across all features, including seismic attributes and volume of shale values, which inherently range from 0 to 1. data normalization was performed using following equation 2: x x x xnormalized max = -( ) ( ) min x min (2) data standardization was performed using following equation 3: x of range standardized = -( )x mean standard deviation of range (3) ann analysis was performed in tibco statistica within the statistica (neural nets) module. the process consists of the general selection of the ann architecture constraints (minimum and maximum number of neurons in the hidden layer, activation functions and number of networks to be trained and retained), and the distribution of data into training, test and validation datasets. in this study, 80% of the cases were used for the training dataset, while the remaining 20% figure 3. well logs for well-1: the sp log is shown in red, the calculated volume of shale is represented in blue, and resistivity logs in both red and blue. green and black horizontal lines indicate the regional markers “α” and “rs7”. g eo lo gi a c ro at ic a 178 geologia croatica 78/2 was evenly split between testing and validation. the number of iterations of the learning process is not strictly defined but is in the function of the prediction error decay. the learning process stops when the error on the training dataset does not significantly change or the error value is extremely variable for 20 consecutive iterations. the workflow follows three possible end conditions. the first occurs when optimal parameters are achieved, ensuring accurate predictions. the second arises when the ann algorithm fails to predict the target variable, resulting in random output values. the third end condition is triggered when error values in the test and validation dataset begin to rise, indicating overtraining of the ann. in all cases, the final network parameters are determined based on their optimal performance across the training, test, and validation datasets. for prediction, 747,800 cells were generated within the geological model (fig. 4c, d), with appended seismic attribute values. the trained anns (using raw, standardized, and normalized datasets) were applied to predict shale volume for each cell. well-log interpretation was performed using interactive petrophysics (ip 2021) software, petrel schlumberger software package was used for seismic interpretation, attribute extraction, and model construction, and statistica tibco for ann analysis. additional calculations were performed in excel. 4. results four subsurface models were constructed to determine the optimal layer thickness for the training and prediction process. these models varied only in the number of layers, which were set to 20, 100 and 200. the corresponding vertical point spacings for these models were an average of 79 m, 16 m and 8 m, respectively. the layering itself has an impact on the analysis in two ways. first, the layer height has a direct effect on the upscaling of the vsh and seismic attribute values. as the layer thickness increases, more values will be averaged representing one data point in the well trajectory (fig. 4b). secondly, the number of cases for the ann analysis significantly decreases from 1888 for the 200-layer case to 193 for the 20-layer case. this has a significant impact on the degree of success of the anns training process as it is sensitive to the number of cases for analysis (alwosheel et al., 2018). numerous iterations of the ann parameters were tested to obtain the best output, as determined by correlation coefficients. the optimal neural network architecture was achieved with a learning rate of 80%, using a neural architecture search as the optimizer and the correlation coefficient as the error metric. regarding predictions based on standardized and normalized data, the logistic sigmoid function proved to be the best activation function for both the hidden and output layers. in contrast, for raw data, best performance was obtained using the logistic sigmoid function for the hidden layer and the sinusoidal function for the output layer. the predictive performance of anns for the volume of shale values was evaluated using correlation coefficients of the target (interpreted vsh value) and the predicted value of vsh (table 1), with the correlation coefficient serving as the primary metric for distinguishing between highand lowefficient neural networks. the highest predictive accuracy was achieved in the model with most layers (table 1, model 200 layers). among the tested models, the ann trained on input data from the 200-layer model demonstrated to be the most successful and was therefore selected for further investigation (table 1). anns trained on models with less than 100 layers had poorer performance (20-layer model) or were completely unable to predict the vsh data (50-layer model which was omitted from the study). to predict the volume of shale across the entire 3d seismic coverage, a model with 747,800 cells was generated (fig. 4c, d), each containing values from 12 selected seismic attributes. these input data were processed using the same methodology as the training dataset. the most effective ann architecture was then deployed to predict the volume of shale values across figure 4. a, b) the blue surface represents the top pannonian surface, while the purple surface denotes the base pannonian surface. red points indicate cells containing values for 12 seismic attributes and volume of shale (vsh), which served as training input data for the artificial neural networks (anns); c, d) white points represent the data points where ann predicted the volume of shale (vsh) based on assigned seismic attribute values. table 1. correlation coefficients representing the performance of artificial neural networks for the three differently layered models. bold results represent the model which is selected for artificial neural network analysis to predict the volume of shale values throughout the investigated area. the network architecture is represented by the number of neurons in the input, hidden and output layer, while the number in brackets indicates the number of learning iterations. input data correlation coefficients model 20 layers model 100 layers model 200 layers raw 0.34 0.49 0.68 normalized (norm) 0.31 0.60 0.70 standardized (std) 0.33 0.43 0.72 network architecture raw 12-123-1 (23) 12-161-1 (83) 12-128-1 (270) normalized (norm) 12-181-1 (22) 12-138-1 (124) 12-145-1 (208) standardized (std) 12-132-1 (21) 12-168-1 (92) 12-80-1 (209) g eologia c roatica 179kamenski et al.: shale volume, seismic attributes, and proper data preparation: critical components for modelling subsurface lithology distribution mineral composition of the pannonian sandstones, which are lithic arenites with significant content of calcite, feldspars and micas (matošević et al., 2023, 2024a, 2024b). namely, pimienta et al. (2019) indicate significant differences in the resistivities of quartz-rich sandstones and feldspar rich sandstones, the latter showing significantly lower resistivities which could result in overestimated values of shale volume. gamma ray (gr) cannot be used in the studied settings for the same reason – the significant content of feldspars and micas in the upper miocene sandstones, i.e. their potassium content, affects the gr readings (imam & trewin, 1991) leading to overestimated volume of clay/shale values (kamel & mabrouk, 2003). the thorium content from the spectral radioactivity log could be considered (rider, 2002) in a given setting, but the problem was the availability of spectral radioactivity logs that are very rare for the study area. sp should not be used to estimate shale volume in areas where formation water resistivity (rw) is not much different from mud filtrate resistivity (rmf) (kamel & mabrouk, 2003), but that was not a limiting factor in the study area where the mud filtrate generally shows significantly different resistivity compared to the formation water. however, the shallower parts of the investigated unit/intervals could be affected by this limitation, due to the lower total dissolved solids (tds) of the formation water, but short intervals of formation water salinity change mostly coincided with the upper boundary of the model – well top “α”, top pannonian surface. the upscaled volume of shale values served as the input variable for modelling, ensuring continuity rather than discrete categorization, as seen in previous studies (brcković et al., 2017; kamenski et al., 2020). this approach demonstrated the successful application of continuous input data in artificial neural networks, a methodology not commonly adopted in earlier research. additionally, the upscaling process was carefully managed by implementing thin layering, effectively preventing overestimation of the predominant lithology. this was evident by the network performance increase with the increase of the number of layers within the geological model. oversimplification in geological models with layers thicker than 16 metres led to poor performance or the complete inability of the ann processing the input data to predict the vsh. based on the performance of the ann training (table 1, model 200 layers), the best results were achieved using standardized input data, followed by normalized data and, lastly, raw data. it is anticipated that normalized or standardized input data would yield better predictions, as raw data contains original seismic attribute values that show significant variations and difference in magnitude. for example, the range of 3d curvature spans from -0.56 to 2.33, original amplitude units range from -63,668.92 to 52,227.58, and envelope values range from 459.39 to 73,946.72, while the volume of shale (vsh) values range from 0 to 1. this high inconsistency in scale poses substantial challenges for anns to accurately predict vsh from seismic attributes. the nor malization and standardization processes enable a more balanced representation of the features, improving model performance. the target dataset, which consisted solely of 3d seismic attribute values. table 1 demonstrates that standardized data produced the most efficient ann predictions, whereas raw datasets yielded the least accurate predictions (table 1, model 200 layers). predicted shale volume values were categorized as follows: ≤0.5 as sandstone, 0.5–0.7 as sandstone-shale, and ≥0.7 as shale. these classifications were upscaled for lithology modelling, resulting in three distinct models corresponding to raw, standardized, and normalized input data (fig. 5). the predicted lithology distribution for the model constructed from standardized (std) input data suggests 52.17% shale, 29.89% sandstone-shale and 17.94% sandstone. for the model based on normalized (norm) input data, the distribution was 55.14% shale, 42.59% sandstone-shale, and 2.27% sandstone. predictions from raw (raw) input data resulted in 38.12% shale, 48.57% sandstone-shale, 13.31% sandstone. 5. discussion the volume of shale (vsh) was calculated from the spontaneous potential (sp) log. the neutron log was not used due to the simple fact that only small intervals in the wells had a neutron log recorded, so in order to preserve consistency across the investigated interval, the electrolog was expected to be a better solution. also, the neutron log is, due to its shallow depth of penetration and consequential effect of wellbore conditions caused by the increased well diameter in clayey rocks, prone to misleading volume of shale estimates (kamayou et al., 2021). the resistivity log was not used be cause of the figure 5. lithology models developed using predicted volumes of shale values derived from: a, b) standardized (std) input data; c, d) normalized (norm) input data; and e, f) raw input data. g eo lo gi a c ro at ic a 180 geologia croatica 78/2 better performance of standardization compared to normalization can be attributed to the original data being more accurately characterized by mean and standard deviation, resulting in a standardized value range of -10.53 to 14.13, as opposed to the constrained normalization range of 0 to 1. these findings strongly suggest that preprocessing data, either by standardization or normalization, is essential for accurately predicting the volume of shale values from seismic attributes. however, the results from lithology modelling offer distinct insights into the impact of data preprocessing on model accuracy and geological consistency. while preprocessing input data generally improves model performance, this study confirms that the benefits are particularly pronounced when using standardized input data. the lithological model generated with std data produced results that align closely with geological expectations, exhibiting features such as welldeveloped meander channels filled with sandstones. these results are not only statistically reliable but also geologically meaningful, as they are supported by numerous independent geological studies (špelić et al., 2023; pavelić & kovačić, 2018 and references therein). the enhanced accuracy of this model suggests that standardization effectively preserves and enhances key lithological trends within the dataset. in contrast, models constructed using normalized (norm) input data produced less reliable predictions. in some cases, their performance was even inferior to models developed using raw (unprocessed) data. this suggests that normalization may distort the original statistical relationships between variables, leading to a loss of critical geological information. notably, the model derived from raw input data exhibited a significant underestimation of the total volume of sandstones, highlighting the risks associated with inadequate preprocessing. the omission or misrepresentation of such key geological features could lead to inaccurate interpretations of reservoir quality, depositional environments, or resource potential. these findings underscore the crucial role of data preprocessing in artificial neural network (ann)-based lithology distribution modelling. proper standardization of the input data has resulted in geologically accurate and statistically reliable models, reinforcing the importance of preprocessing in machine learning applications within geosciences. however, normalization appears to compromise model reliability, making it an unsuitable preprocessing method for lithological modelling. as a result, careful selection of preprocessing techniques is essential for ensuring reliable, geologically consistent predictions in lithology modelling. this study proved that combining machine learning with traditional geological methods holds great potential for improving predictive capabilities in the geosciences. the approach presented here is applicable in geological settings characterized by the relative uniformity of lithological composition, i.e. in settings with two to three main distinctive lithologies that can be distinguished based on the geophysical exploration data from wells. this approach is therefore expected to be applicable in constructing the model of coal bearing strata, where the density log could be used to identify different lithological categories. it could also be used for the characterization of shale-rich carbonates, i.e. the spatial zonation of carbonate reservoirs with respect to shale volume. modelling the spatial distribution of lithological composition prior to porosity modelling can be beneficial, as each lithological category can be associated with a specific porosity range (kolenković močilac et al., 2022). this approach allows the lithological model to control the porosity model, therefore representing a significant improvement over a simple sandstone-shale system. additionally, the methodology offers potential for various geo-energy explorations, including hydrocarbon and geothermal explorations, as well as co2 storage assessments. however, in more complex lithological settings, this methodology would require further refinement and development to achieve optimal accuracy. the transfer of this methodology to other settings is conditioned not only by geological characteristics but also by differences in the input data set. the presented methodology is limited to 3d seismic data due to the usage of a large number of attributes, some of which are not at all suited for calculation on 2d seismic data. furthermore, the effectiveness of standardization over normalization is linked to the specific numerical value ranges of the seismic attributes in this study. these ranges are not necessarily the same for all 3d volumes, meaning that in other cases, normalization may yield better results. therefore, the transferability of direct ann parameters to other regions with different input data is not expected to be as successful; however, the developed methodology concept has high potential to improve lithology prediction across diverse geological settings. 6. conclusion this study presents an ann approach for determining the subsurface lithology distribution based on well log and 3d seismic data. the importance of data preprocessing in annbased lithology modelling is highlighted. standardized input data produced geologically consistent results, accurately representing key features including fluvial meander channels filled with sandstones. in contrast, models using normalized data were less reliable, sometimes even underperforming compared to those using raw data, which significantly underestimated sandstone volume. these findings emphasize that standardization enhances model accuracy, while normalization should be avoided as it can compromise lithology predictions. the limitations of the approach presented in this work are mainly related to the estimation of the volume of shale, since the volume of shale represents a key input parameter, and its estimate is influenced by the available dataset as well as specific geological settings. furthermore, there is a certain amount of subjectivity of the interpreter affecting the final result, but these issues are inherent to all analyses which are influenced by the volume of shale parameter. the approach is suitable for geological settings with two to three main lithologies, distinguishable through geophysical well data. it can be applied to coal-bearing strata using density logs or to shale-rich carbonates for reservoir zonation. however, for geologically complex settings, it requires significant refinement. g eologia c roatica 181kamenski et al.: shale volume, seismic attributes, and proper data preparation: critical components for modelling subsurface lithology distribution acknowledgement this research was conducted as part of the project funded by the croatian science foundation (no. hrzz uip-2019-043846): “geological characterization of the eastern part of the drava depression subsurface intended for the evaluation of energy potentials (geodep).” the authors express their sincere gratitude to schlumberger for generously providing the petrel academic software license and geoactive for providing academic software licences for interactive petrophysics. additionally, we extend our appreciation to the croatian hydrocarbon agency for granting access to the data, without which this research would not have been possible to conduct. authors would like to thank professor marijan kovačić as welll as an anonymous reviewer for their thorough and detailed review. their insightful comments helped to identify and address shortcomings, ultimately improving the quality of the manuscript. references alwosheel, a., van cranenburgh, s. & chorus, c.g. (2018): is your dataset big enough? sample size requirements when using artificial neural networks for discrete choice analysis.– journal of choice modelling, 28, 167–182. https://doi.org/10.1016/j.jocm.2018.07.002 asquith, g. & krygowski, d. (2004): basic well log analysis.– aapg methods in exploration 16, 21-30. bakrač, k., hajek-tadesse, v., miknić, m., grizelj, a., hećimović, i. & kovačić, m. (2010): evidence for badenian local sea level changes in the proximal area of the north croatian basin.– geologia croatica, 63/3, 259-269. https://doi.org/10.4154/gc.2010.21 brcković, a., kovačević, m., cvetković, m., kolenković močilac, i., rukavina, d. & saftić, b. (2017): application of artificial neural networks for lithofacies determination based on limited well data.– central european geology, 60/3; 299–315. https://doi. org/10.1556/24.60.2017.012 bornard, r., allo, f., coléou, t., freudenreich, y., caldwell, d.h. & hamman, j.g. (2005): petrophysical seismic inversion to determine more accurate and precise reservoir properties. spe, 94144. chopra, s. & marfurt, k. (2006): seismic attributes – a historical perspective.– geophysics, 70/5, 3so–28so. http://doi.org/10.1190/1.2098670 cvetković, m. (2017): possibilities for well log correlation using standard deviation trends in neogene-quaternary sediments, sava depression, pannonian basin.– geologia croatica, 70/2, 79–85. https://doi. org/10.4154/gc.2017.07 cvetković, m., matoš, b., rukavina, d., kolenković močilac, i., saftić, b., baketarić, t., baketarić, m., vuić, i., stopar, a., jarić, a. & paškov, t. (2019): geoenergy potential of the croatian part of pannonian basin: insights from the reconstruction of the pre-neogene basement unconformity.– journal of maps, 15/2, 651–661. https://doi.org/10.1080/17445647.2019.1645052 ćorić, s., pavelić, d., rögl, f., mandic, o., vrabac, s., avanić, r., jerković, l. & vranjković, a. (2009): revised middle miocene datum for initial marine flooding of north croatian basins (pannonian basin system, central paratethys).– geologia croatica, 62/1, 31–43. https://doi.org/10.4154/gc.2009.03 djeddi, m. (2016): transformée de hilbert, signal analytique et attributs sismiques.– département de géophysique, fhc-université m’hamed bougara de boumerdes, algérie. dolton, g.l. (2006): pannonian basin province, central europe (province 4808) – petroleum geology, total petroleum systems, and petroleum resource assessment.– bulletin of the united states geological survey 2204, 47. feng, y., wen, g., shang, j., wen s. & wu, b. (2024): research on 3d geological modeling based on boosting integration strategy.– ore geology reviews, 171, 106157. https://doi.org/10.1016/j.oregeorev.2024.106157 fodor, l., csontos, l., bada, g., györfi, i. & benkovics, l. (1999): tertiary tectonic evolution of the pannonian basin system and neighbouring orogens: a new synthesis of palaeostress data.– geological society, london, special publications, 156/1, 295-334. https://doi. org/10.1144/gsl.sp.1999.156.01.15 horváth, f. & cloetingh, s. (1996): stress-induced late-stage subsidence anomalies in the pannonian basin.– tectonophysics, 266/1–4, 287–300. https://doi.org/10.1016/s0040-1951(96)00194-1 imam, md.b. & trewin, n.h. (1991): factors contributing to high gamma-ray levels in upper jurassic sandstone reservoirs of the claymore oilfield, north sea.– marine and petroleum geology, 8/4, 452–460. https://doi.org/10.1016/0264-8172(91)90067-b iturrarán-viveros, u. & parra, j.o. (2014): artificial neural networks applied to estimate permeability, porosity and intrinsic attenuation using seismic attributes and well-log data.– journal of applied geophysics, 107, 45–54. https://doi.org/10.1016/j.jappgeo.2014.05.010 kamayou, v., ehirim, c. & ikiensikimama, s. (2021): estimating volume of shale in a clastic niger delta reservoir from well logs: a comparative study.– international journal of geosciences, 12, 949–959. https://doi.org/10.4236/ijg.2021.1210049 kamel, m.h. & mabrouk, w.m. (2003): estimation of shale volume using a combination of the three porosity logs.– journal of petroleum science and engineering, 40/3-4, 145–157. https://doi.org/10.1016/ s0920-4105(03)00120-7 kamenski, a., cvetković, m., kolenković močilac, i. & saftić, b. (2020): lithology prediction in the subsurface by artificial neural networks on well and 3d seismic data in clastic sediments: a stochastic approach to a deterministic method.– gem international journal on geomathematics, 11/8, 1–24. https://doi.org/10.1007/s13137-020-01453 kamenski, a., cvetković, m., kapuralić, j., kolenković močilac, i. & brcković, a. (2024): from traditional extrapolation to neural networks: time-depth relationship innovations in the subsurface characterization of drava basin, pannonian super basin.– advances in geo-energy research, 14/1, 25–33. https://doi.org/10.46690/ ager.2024.10.05 ker, s., le gonidec, y., marsset, b., westbrook, g.k., gibert, d. & minshull, t.a. (2014): fine-scale gas distribution in marine sediments assessed from deep-towed seismic data.– geophysical journal international, 196/3, 1466–1470. https://doi.org/10.1093/gji/ggt497 kolenković močilac, i., cvetković, m., saftić, b. & rukavina, d. (2022): porosity and permeability model of a regionally extending unit (upper miocene sandstones of the western part of sava depression, croatia) based on vintage well data.– energies (basel), 15/16, 1–18. https://doi.org/10.3390/en15166066 koson. s., chenrai, p. & choowong, m. (2014): seismic attributes and their applications in seismic geomorphology.– bulletin of earth sciences of thailand, 6/1, 1–9. kovačić, m. & grizelj, a. (2006): provenance of the upper miocene clastic material in the southwestern part of the pannonian basin.– geologica carpathica, 57, 495−510. li, w., yue, d., wu, s., shu, q., wang, w., long, t. & zhang, b. (2019): thickness prediction for high-resolution stratigraphic interpretation by fusing seismic attributes of target and neighboring zones with an svr algorithm.– marine and petroleum geology, 113, 104153. https:// doi.org/10.1016/j.marpetgeo.2019.104153 liu, j. & marfurt, k.j. (2006): thin bed thickness prediction using peak instantaneous frequency.– seg technical program expanded, abstracts society of exploration geophysicists, 968–972. http://doi. org/10.1190/1.2370418 lučić, d., saftić, b., krizmanić, k., prelogović, e., britvić, v., mesić, i. & tadej, j. (2001): the neogene evolution and hydrohttps://doi.org/10.3390/en15166066 g eo lo gi a c ro at ic a 182 geologia croatica 78/2 carbon potential of the pannonian basin in croatia.– marine and petroleum geology, 18, 133–147. https://doi.org/10.1016/s0264-8172(00) 00038-6 malvić, t. & cvetković, m. (2013): lithostratigraphic units in the drava depression (croatian and hungarian parts) – a correlation.– nafta, 64/1, 27–33. marković, f., kuiper, k., ćorić, s., hajek-tadesse, v., hernitz kučenjak, m., bakrač, k., pezelj, đ. & kovačić, m. (2021): middle miocene marine flooding: new 40ar/39ar age constraints with integrated biostratigraphy on tuffs from the north croatian basin.– geologia croatica, 74/3, 237-252. https://doi.org/10.4154/gc.2021.18 matošević, m., marković, f., bigunac, d., šuica, s., krizmanić, k., perković, a., kovačić, m. & pavelić, d. (2023): petrography of the upper miocene sandstones from the north croatian basin: understanding the genesis of the largest reservoirs in the southwestern part of the pannonian basin system.– geologica carpathica, 74/2, 155– 179. https://doi.org/10.31577/geolcarp.2023.06 matošević, m., šuica, s., bersani, d., marković, f., razum, i., grizelj, a., petrinjak, k., kovačić, m. & pavelić, d. (2024a). the alps as the main source of sand for the late miocene lake pannon (pannonian basin, croatia).– geologia croatica, 77/2, 69-83. https://doi. org/10.4154/gc.2024.05 matošević, m., tomašić, n., perković, a., kampić, š., kovačić, m. & pavelić, d. (2024b): reservoir quality evaluation: unveiling diagenetic transformations through mineralogical and petrophysical analyses of the upper miocene lacustrine sandstones in the pannonian basin system, croatia.– rudarsko-geološko-naftni zbornik, 39/3, 153– 172. https://doi.org/10.17794/rgn.2024.3.12 mohammadinia, f., ranjbar, a., kafi, m., shams, m., haghighat, f. & maleki, m. (2023): shale volume estimation using ann, svr, and rf algorithms compared with conventional methods.– journal of african earth sciences, 205, 104991. https://doi.org/10.1016/j. jafrearsci.2023.104991 novak zelenika, k., novak mavar, k. & brnada, s. (2018): comparison of the sweetness seismic attribute and porosity–thickness maps, sava depression, croatia.– geosciences, 8, 426. https://doi. org/10.3390/geosciences8110426 othman, a., fathy, m. & mohamed, i.a. (2021): application of artificial neural network in seismic reservoir characterization: a case study from offshore nile delta.– earth science informatics, 14, 669– 676. https://doi.org/10.1007/s12145-021-00573-x oumarou, s., mabrouk, d., tabod., t.c., marcel, j., ngos iii, s., essi, j.m.a. & kamguia, j. (2021): seismic attributes in reservoir characterization: an overview.– arabian journal of geosciences, 14, 402. https://doi.org/10.1007/s12517-021-06626-1 palacky, g.v. (1988): resistivity characteristics of geologic targets.– in: electromagnetic methods in applied geophysics, 1, 53-129. tulsa, ok: society of exploration geophysicists. https://doi.org/10.1190/1.97815 60802631.ch3 pamić, j. (1998): crystalline basement of the south pannonian basin based on surface and subsurface data.– nafta, 49, 371–390. pamić, j. & lanphere, m. (1991): hercynian granites and metamorphic rocks from the mts. papuk, psunj, krndija, and the surrounding basement of the pannonian basin in slavonija (northern croatia, yugoslavia).– geologija, 34/1, 81–253. https://doi.org/10.5474/geologija.1991.004 pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.– basin research, 13, 359–376. https://doi.org/10.1046/j.0950-091x.2001.00155.x pavelić, d. & kovačić, m. (2018): sedimentology and stratigraphy of the neogene rift-type north croatian basin (pannonian basin system, croatia): a review.– marine petroleum geology, 91, 455–469. https://doi. org/10.1016/j.marpetgeo.2018.01.026 pigott, j.d., kang, m.-h. & han, h.-c. (2013): first order seismic attributes for clastic seismic facies interpretation: examples from the east china sea.– journal of asian earth sciences, 66, 34–54. https://doi.org/10.1016/j.jseaes.2012.11.043 pimienta, l., orellana, l.f. & violay, m. (2019): variations in elastic and electrical properties of crustal rocks with varying degree of microfracturation.– journal of geophysical research: solid earth, 124, 6376–6396. https://doi.org/10.1029/2019jb017339 rider, m.h. (2002): the geological interpretation of well logs (second edition).– sutherland, rider-french consulting, 280 p. rögl, f. (1999): mediterranean and paratethys – facts and hypotheses of an oligocene to miocene paleogeography (short overview).– geologica carpathica, 50/4, 339–349. rukavina, d., saftić, b., matoš, b., kolenković močilac, i., premec fuček, v. & cvetković, m. (2023): tectonostratigraphic analysis of the syn-rift infill in the drava basin, southwestern pannonian basin system.– marine and petroleum geology, 152, 106235, 23. https:// doi.org/10.1016/j.marpetgeo.2023.106235 saftić, b., velić, j., sztanó, o., juhász, g. & ivković, ž. (2003): tertiary subsurface facies, source rocks and hydrocarbon reservoirs in the sw part of the pannonian basin (northern croatia and south-western hungary).– geologia croatica, 56, 101–122. https://doi.org/10.4154/232 schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine-carpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss journal of geosciences. 101, 139– 183. https://doi.org/10.1007/s00015-008-1247-3 serra, o. (1984): 4. the spontaneous potential–sp.– in serra, o. (ed.): developments in petroleum science, elsevier, 15, part a, 77–88. https:// doi.org/10.1016/s0376-7361(08)70418-7 smirnoff, a., boisvert, e. & paradis, s.j. (2008): support vector machine for 3d modelling from sparse geological information of various origins.– computers & geosciences, 34/2, 127–143. https://doi.org/10.1016/j.cageo.2006.12.008 subrahmanyam, d. & rao, p.h. (2008): seismic attributes – a review.– 7th international conference & exposition on petroleum geophysics, university of hyderabad, hyderabad, 398–403. špelić, m., kovács, á., saftić, b. & sztanó, o. (2023): competition of deltaic feeder systems reflected by slope progradation: a high-resolution example from the late miocene-pliocene, drava basin, croatia.– international journal of earth sciences, 113, 1–19. https://doi.org/10.1007/ s00531-023-02290-w taheri, m., ciabeghodsi, a.a., nikrouz, r. & kadkhodaie, a. (2021): modeling of the shale volume in the hendijan oil field using seismic attributes and artificial neural networks.– acta geologica sinica (english edition), 95/4, 1322–1331. https://doi.org/10.1111/17556724.14739 taner, m.t. (2001): seismic attributes.– recorder, canadian society of exploration geophysicists, houston, usa, 26/7, 26–48. taner, m.t., sherif, r.e., koehler, e.d.f. (1976): extraction and interpretation of the complex seismic trace.– in: 6th annual convention proceedings, seg, huston, texas, 2, 305–316. velić, j. (2007): petroleum geology [geologija ležišta nafte i plina – in croatian].– in zorić, i. (ur.). university of zagreb, faculty of mining, geology and petroleum engineering, zagreb. vrsaljko, d., pavelić, d., miknić, m., brkić, m., kovačić, m., hećimović, i., hajek-tadesse, v., avanić, r. & kurtanjek, n. (2006): middle miocene (upper badenian/sarmatian) palaeoecology and evolution of the environments in the area of medvednica mt. (north croatia).– geologia croatica, 59, 51–63. vukadin, d. (2022): development of seismic interpretation procedure based on seismic inversion for the bjelovar depression reservoirs [razvoj postupka seizmičke interpretacije ležišta ugljikovodika bjelovarske depresije na temelju inverzije seizmičkih brzina – in croatian].– phd. university of zagreb, faculty of mining, geology and petroleum engineering, zagreb. https://doi.org/10.1016/s0264-8172(00)00038-6 https://doi.org/10.1016/s0264-8172(00)00038-6 https://doi.org/10.4154/gc.2021.18 https://doi.org/10.1190/1.9781560802631.ch3 https://doi.org/10.1190/1.9781560802631.ch3 g eologia c roatica 183kamenski et al.: shale volume, seismic attributes, and proper data preparation: critical components for modelling subsurface lithology distribution orefield, tongling copper district, china.– natural resources research, 34, 121–147. https://doi.org/10.1007/s11053-024-10430-5 zhou, c., ouyang, j., ming, w., zhang, g., du, z. & liu, z. (2019): a stratigraphic prediction method based on machine learning.– applied sciences, 9/17, 3553. https://doi.org/10.3390/app9173553 xu, q. & haq, u.b. (2022): seismic facies analysis: past, present and future.– earth-science reviews, 224, 103876. https://doi.org/10.1016/j.earscirev.2021.103876 zhou, f. & liu, l. (2024): machine learning prediction of deep potential ores and its explanation based on integration of 3d geological model and numerical dynamics simulation: an example from dongguashan 2018 | 71/2 | 113–119 | 3 figs. | 1 tab. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction te waikoropupū springs are the largest freshwater springs in new zealand with an average flow of 13.3 m3/sec and they have some of the clearest water in the world with a black-disc visibility of 63 m (stewart & thomas, 2008; davies-colley & smith, 1995). they are part of the large karst arthur marble aquifer (ama) complex. the springs are regarded as one of the main tourist attractions in golden bay with 90,000 visits annually. furthermore, they are a registered wahi tapu (sacred place), are a taonga tuku iho (treasure) for the three local iwi (tribes) and are listed in new zealand as a water of national importance for biodiversity and wetland values. recently, because of these extremely high natural values, ngāti tama manawhenua ki te tau trust and andrew yuill applied for a new zealand water conservation order (wco) for the springs and the ama (ngāti tama ki te waipounamu trust & yuill, 2017). the springs are located in the lower takaka valley, golden bay, about 4 km from the coast (figure 1; williams, 2004). as dairy farming in the valley bottom has intensified there has been a growing concern with increasing nitrate-n concentrations in the springs (mead, 2015). the impacts of increasing cow numbers are recognised as a major freshwater environmental problem in many parts of new zealand (scarsbrook et al., protecting the karst te waikoropupū springs in new zealand donald j mead 26 gibbs road, collingwood, 7073, new zealand; (don.mead@gmail.com) doi: 10.4154/gc.2018.08 abstract the sacred te waikoropupū springs are new zealand’s largest, have some of the clearest freshwater worldwide and are a major tourist attraction. they are part of a large karst system, the arthur marble aquifer complex of 180 km2 that has two main interconnected aquifers which have mean residence times of 10.2 and 1.2 years, respectively. the springs have a high water clarity of 63 m, due to the action of biofilms and stygofauna in the aquifers; to protect this water clarity it is recommended that the level of no3-n in the springs should not exceed 0.4 mg/l. in the aquifers’ unconfined zone there are 45 km2 of lowland, free-draining gravels that receive over 2000 mm/a rainfall. the intensification of dairy farming on these soils has resulted in the springs no3-n rising to above this trigger concentration of 0.4 mg/l. three processes, in order of effectiveness, are being considered to control farm impacts on water quality: 1. dairy farmers have volunteered to stop cattle having direct access to waterways, to manage their dairy-shed waste better and to plant narrow riparian strips. there is some evidence this has reduced farming impacts to waterways. 2. the second method, promoted by the local regional council, is to have stakeholders, assisted by professionals, to recommend water allocation and water quality guidelines for inclusion in their regional plan. this method is ongoing. however, it could be captured by special interest groups and the rules could be relaxed over time. consultation with the local indigenous iwi (tribe), who have strong spiritual values for water, is essential. 3. to afford the strongest protection a local iwi, ngāti tama, and andrew yuill have applied for a water conservation order (wco) on the springs complex and aquifers. this is allowed for in new zealand law, would provide the strongest long-term protection and, when granted, has to be implemented by the council. a very recent, but untested, alternative would be to give the waterbody personhood (legal status equivalent to a human), to be managed by guardians. this has been done for one new zealand river. to protect the aquifers, the wco, which offers the greatest control, is recommended. 2016; julian, et al., 2017) and as williams (2004) has stated, karst systems are particularly susceptible to pollution. this paper looks at the management options to ensure that te waikoropupū springs and associated aquifers are sustainably managed and their high values are conserved. while these options are detailed in a new zealand context the experience should be more widely applicable. 2. hydrogeological and land-use setting the geology and hydrology of the recharge area supplying te waikoropupū springs and its main marble aquifer have been described in detail by ford & williams (1989); williams (1977, 2004); mueller (1991); stewart & thomas (2008) and thomas & harvey (2013) and is only briefly described here (figure 1). the area of the ordovician arthur marble is about 180 km2 and has a thickness of 500 to perhaps 1000 m. shallow permeable quaternary gravels from a few to 50 m thickness cover about 90 km2 of the takaka valley bottom but in the downstream half of the area these gravels are underlain by the impermiable tertiary motupipi coal measures (increasing from zero in upper the takaka valley to 305-500 m close to the sea) which form the main cap of the artesian system (williams, 1977; williams pers. comm.). other tertiary formations include the tarakohe article history: manuscript received december 11, 2017 revised manuscript accepted may 25, 2018 available online june 21, 2018 keywords: water quality, nitrate, dairy farming, environmental protection, conservation order g eo lo gi a c ro at ic a geologia croatica 71/2114 mudstone (600 m thick) and the takaka limestone (on the northern and eastern side of takaka valley and 4 62 m thick). these formations overlie the arthur marble. the total area of unconfined marble aquifer is 135 km2 of which over 45 km2 is covered by the valley bottom gravels (williams, 2004). the takaka and waingaro rivers and the unconfined gravels, which are important for the recharge of the ama, are major contributors of water to the ama (williams, 2004; stewart & thomas, 2008). further allogenic recharge areas of about 80 km2 occur on the higher hills above the marble formation (williams, 2004; stewart & thomas, 2008). stewart & thomas (2008) have suggested there are two parts to the ama that supply the springs a larger ‘deep’ marble aquifer with a storage volume of 3 km3 and a ‘shallow’, smaller marble aquifer with 0.4 km3 of water. these aquifers are hydraulically connected but may operate fairly independently. there are two main springs at te waikoropupū. the main spring (figure 2) and the small adjacent dancing sands spring, which together have an average flow of 10 m3/sec, are largely fed by water from the deeper part of the marble aquifer with about a quarter being supplied by the shallow part of the aquifer (stewart & thomas, 2008). this main spring has a diameter of 60 m and has several vents (figure 2; williams, 2007). the fish creek springs are located at about 200 m to the south east and at 3 m higher elevation than the main spring. they have about a third of the flow rate of the main spring and three-quarters of their flow is from the ‘shallow’ aquifer (stewart & thomas, 2008). water balance calculations for the ama complex indicate a total discharge of ~20 m3/sec, implying there is some discharge into the ocean (williams, 2004; stewart & thomas, 2008). there are about 200 doline depressions in the lowland pastures (figure 3; thomas & harvey, 2013). isotope and other measurements of the springs waters indicate that the mean residence time of water in the ‘deep’ marble aquifer is 10.2 years, although the peak age of discharge is 3 years and there is a long tail of older water (stewart & thomas, 2008). the ‘shallow’ part of the aquifer has a mean residence time of 1.2 years with a peak at 0.9 years. the water in this shallow aquifer system is largely recharged from the upper takaka river and by valley rainfall. rainfall is high ranging from 2000 to 3500 mm/a, but pastures on the stony soils are usually water limited in summer (thomas & harvey, 2013). the high clarity of te waikoropupū springs is due to oxidization of colored organic matter by biofilms and stygofauna as it passes through the aquifers (ngāti tama ki te waipounamu trust & yuill, 2017, fenwick, 2016). as the ecology has not been researched, a precautionary approach is needed to protect this ecosystem. pastoral farming with sheep began in the takaka valley in the latter half of the 19th c and in the early 20th c following the felling of the native forest (mead, 2015). dairy farming was initially small scale but by the mid-1970s there were about 2500 cows being milked on the lowland unconfined aquifer. this expanded rapidly in the 1990s with increased irrigation (predominantly after 2007) and use of nitrogen fertilizer and imported supplementary feeds. dairy cows in the unconfined aquifer zone increased between 2005 and 2014 from 5,500 to 6,700 animals and this was followed by a decline to 6200 cows in 2017 (tasman district council (tdc), pers. comm.). there is an informal cap on water allocation in the unconfined area. this was fully allocated by 2012, and enabled about 45% of the dairy pastures (1020 ha) to be irrigated. dairy cows and beef cattle often lead to high leaching of nitrate-n (scarsbrook et al., 2016). thus nitrate-n in the main spring is 0.4 mg/l compared to <0.1 mg/l found in waterways in non-pasture areas (mead, 2015). the national policy statement on freshwater management (npsfm, 2014) and australian and new zealand environment and conservation council (anzecc, 2000) guidelines currently only cover rivers and lakes and do not have criteria for groundwater. in new zealand the drinking water must have than nitrate-n concentration below 11.3 mg/l. to better define the current nutrient status, friends of golden bay (inc) have been sampling the main and fish springs weekly since february 2016. this research highlighted that in the main spring the median nitrate-n concentration to march 2017 was 0.40 mg/l but that it increased to 0.44 mg/l between march 2017 and april 2018. fish springs have a slightly lower concentration; they increased over these same periods from 0.36 to 0.40 mg/l. fenwick (2016) has recommended that they should not be allowed to increase so as to safeguard this groundwater ecosystem. 3. legal setting new zealand’s resource management act (rma) governs land and water management (richmond et al., 2004; rouse et al., 2016). the act covers both national and regional levels and has an overarching aim of sustainability. in the case of freshwater, the central government has the npsfw (2014) that local government must comply with. for the te waikoropupū springs and associated aquifers this is tasman district council (tdc). however, currently this policy statement is largely silent on groundwater. the rma has provision for water conservation orders (wcos) that give protection almost equivalent to national parks. there are currently 15 wcos which cover 13 rivers and two lakes. under the rma, local government has the responsibility for setting policies and rules. tdc does not currently have comprehensive freshwater policies although some aspects, such as disposal of dairy shed waste and consents to take water for irrigation or other use, are prescribed. the rma prescribes that, because of the treaty of waitangi, māori values should be considered and be included in decision making (tipa et al., 2016). thus the npsfm (2014) includes māori values, while there is joint management by local iwi (tribes), tdc and the department of conservation for te waikoropupū reserve but not the associated aquifers. in their 2013 treaty of waitangi settlement, it was acknowledged that ngāti tama had a close connection to te waikoropupū springs and the takaka river and its tributaries (ngāti tama ki te waipounamu trust & yuill, 2017). with respect to the springs and ama, ngāti tama iwi have a song for formal occassions that talks about the bubbling waters that are the tears of spirit ancestors and are vital for their people’s health. they believe that huriawa, the guardian spirit of the springs, lives in the underground caves and streams. to them the waters are a link between the past and present. for this reason they state the water is sacred, needs to be protected for future generations and must not be polluted. both local and central government have made use of freshwater stakeholder advisory groups, advised by experts, to give guidance to elected officials (rouse et al., 2016). this advice is not binding. currently the takaka freshwater and land advisory group (tflag) are considering policies and rules that could affect te waikoropupū springs and its aquifers. g eologia c roatica donald j. mead: protecting the karst te waikoropupū springs in new zealand 115 4. protection options there are four options that are or could be employed to help protect te waikoropupū springs and the associated aquifers. these are: 1. voluntary freshwater plans 2. regional freshwater plans 3. national freshwater plans including a wco 4. legal personhood for the springs and aquifers the first three are overlapping. the fourth option is new and untested but is briefly discussed. the evaluation of the various options was made on the basis of new zealand experiences (table 1). 5. discussion in 2003 the dairy industry set up the dairying and clean stream accord; this was replaced in 2013 by the sustainable dairying water accord (holland, 2014). these voluntary plans have made substantial progress on excluding dairy cattle from larger waterways (sometimes with riparian planting), improved dairy shed waste management and more recently helped with farm nutrient management plans. for farmers in the unconfined area of the ama these efforts, along with less dairy intensification, might partly explain the levelling off of nitrate-n concentrations in te waikoropupū springs since 2013. farmers prefer voluntary agreements as they see this as being less costly and bureaucratic (table 1). however, the limitations are that standards or measures may be weak and some farmers will ignore them. just fencing off large streams, for example, does not address nitrate leaching in many situations or possible impacts of further intensification. holland (2014) criticized these dairy accords as they did not measure outcomes in terms of water quality, used voluntary recording and did not include all stakeholders. local government in new zealand has legally enforceable management plans. the tdc plan has or is developing new policies for freshwater, including aquifers. the tdc current plan includes requirements about waste disposal and water allocation but still has to deal with diffuse pollution. water allocation in the unconfined ama recharge zone has only had an interim maximum allocation. the tflag consultation process was set up to address such issues. the use of stakeholder advisory groups is frequently recommended as a means to facilitate decision making that reflects community wishes, including for groundwater (foster & van der gun, 2016; rouse et al., 2016). there can be pitfalls if powerful vested interest groups or politics subvert the process. several interest groups have left the nationally based new zealand’s land and water forum process as the government did not follow key recommendations. rouse et al. (2016) have argued that science advisors to stakeholder groups should act as technical ‘honest brokers’, although they noted it is doubtful that that they can be truly independent. this came to the fore within tflag. during tflag’s process the tdc experts recommended allowing more irrigation in the unconfined part of the aquifer; they also were part of an expert panel sponsored by dairynz to set water quality limits for the springs’ water. their recommendation was to increase the water allocation from the current informal cap of 500 to over 800 l/sec apparently to satisfy the needs of dairy farmers on the waiting list and to allow for any further expansion. to justify this, the scientists argued that it would not affect the ecology of the rivers. however, they did not consider possible impacts of greater farm intensification on the underground aquifers. when this proposal was shared with the wider public, the public came out solidly against further water allocation. thus for a high-conservation-value karst waterbody, such as the ama, using only the regional government approach has some dangers (table 1). further, controls could be relatively easily weakened over time. nationwide rules, such as the npsfm (2014), do have a direct bearing on the rivers in the takaka catchment but currently this policy statement does not have mandated rules for groundwater. the overarching policy is to maintain or improve water quality, which implies that nitrate-n should not be allowed to increase further in the ama and the springs. the ngāti tama ki te waipounamu trust and andrew yuill applied for a wco for te waikoropupū springs and associated aquifers in june 2013 and the minister of conservation accepted the application in may 2017. the high evidence requirement to show that a wdo is essential often makes this process slow. as mentioned above, ngāti tama consider the springs and the aquifer that supply them as a sacred treasure that deserves the highest protection; they have a spiritual connection with the waters. table 1. options for freshwater management in new zealand with examples given in italics. option organisational basis advantages limitations voluntary freshwater plans voluntary agreements best management practice (dairy accords in nz) fewer governmental controls reduced compliance costs weak control of offenders often minimal standards regional freshwater plans policies and rules at the regional level may employ stakeholder advisors (tasman district council and takaka freshwater and land advisory group) potentially controls both water use and quality stakeholder advisory groups helps public buy-in slow implementation, weak compliance and potential gradual erosion of standards. subject to lobby group capture national freshwater plans resource management plan national freshwater policy statement land and water forum (advisory group) water conservation order (tdc must follow wco) potentially gives uniformity and integration with government objectives wco is equivalent to national park status and less susceptible to erosion of standards subject to politics stakeholder groups subject to lobby capture sometimes a lengthy / expensive process legal personhood waterbody will have same legal rights as people management group (iwi and government joint guardians) recognises cultural views that water and people are inseparable untested g eo lo gi a c ro at ic a geologia croatica 71/2116 figure 1. a hydrogeologic map and cross-section of the takaka valley (from ford & williams, 1989). g eologia c roatica donald j. mead: protecting the karst te waikoropupū springs in new zealand 117 figure 1. continued. g eo lo gi a c ro at ic a geologia croatica 71/2118 in their application they have recommended clear water quality guidelines to protect the groundwater ecosystems of this karst system. these cover: • water abstraction, with no reduction in flow from the springs; • pollution by land use practices, including; • excessive biological oxygen demand; • toxins; • nitrates; • and effects on ph. in practice this means sinkholes and streamsides would be off-limits, management practices must avoid affecting the groundwater, while new land-use proposals need to show they will not affect aquifer water quality. the tdc management plan would provide the legal governance, including monitoring and penalties for non-compliance. a wco is a national process under the rma (richmond, et al., 2004). an application to the minister of the environment requires that he sets up a tribunal to advise him on the application. once the wco is accepted the agreed policies and rules become binding on the regional council. the minister was positive when accepting the wco application for te waikoropupū springs and aquifers and tflag has publically welcomed it. a major advantage of the wco is that it will be more difficult to alter and proposed changes would have to be publically notified figure 3. doline in the takaka valley bottom-land pasture (photo by d.j. mead). figure 2. the waikoropupū main spring (photo by d.j. mead). g eologia c roatica donald j. mead: protecting the karst te waikoropupū springs in new zealand 119 (table 1). a disadvantage is that it can sometimes be a long and costly process (richmond et al., 2004). in march 2017 the new zealand government passed an act to give the whanganui river legal personhood as part of its treaty of waitangi settlement to local iwi (new zealand government, 2017). this act recognized that the tribes regarded the river as inseparable from them ‘i am the river and the river is me’. the river is represented by two guardians, one appointed by the iwi and the other by the government. the guardians are advised by consultative groups who also must ensure the river’s health. as this is the first waterbody worldwide to be given the legal status of a person it is too early to know how well this solution will protect the river (table 1). however, it clearly fits the māori worldview that they are inextricably connected with the river and the land. 6. conclusions the very high conservation and iwi values of te waikoropupū springs, coupled with the ongoing pressure for further farming development in the area, makes the use of a wco the most appropriate mechanism for protecting this waterbody. it is equivalent to giving it national park status while acknowledging that farming has already modified the landscape. part of the advantage of the wco is that it can be supported by other processes including farmer-led voluntary agreements and local body and nationwide instruments. a wco is less likely to be captured by vested interests and would be more difficult to change once implemented. in this particular example it has been proposed that there would be no further water abstraction or discharge of contaminants that would cause the proposed limits in the wco to be exceeded. relying solely on voluntary accords or on regional plans, even where these are assisted by stakeholder groups, may not provide the same degree of long-term protection for an outstanding waterbody. stakeholder groups are usually advisory and their recommendations can be overruled at a later stage in the process. there is a danger that technical advisors to advisory groups might not act independently or may overlook some essential attribute. there would be some protection if plans are developed openly and wide debate within society is encouraged (foster & van der gun, 2016). giving te waikoropupū springs legal personhood status might also have been acceptable to the local iwi, although this was not part of their treaty of waitangi settlement. however, this option is untested while wco’s have been used to protect rivers and lakes for many years in new zealand. currently, a wco is the best option to protect te waikoropupū springs and associated aquifers; it is supported by the local community. acknowledgement the author thanks andrew yuill and paul williams for their help in the paper’s preparation. thanks are also due to the two anonymous referees. references anzecc (2000): australian and new zealand guidelines for fresh and marine water quality. vol. 1 and 2. australian and new zealand environment and conservation council and agriculture and resource management council of australia and new zealand: canberra. davies-colley, r.j. & smith, d.g. (1995): optically pure waters in waikoropupū (‘pupu’) springs, nelson, new zealand.n. z. j. marine and freshwater res., 29, 251–256. fenwick, g. (2016): groundwater ecosystems. in: jellyman, p.g., davie, t.j.a., pearson, c.p. & harding, j.s. (eds.): advances in new zealand freshwater science. n.z. freshwater sci. soc. & n.z. hydrol. soc., 345-355. ford, d.c. & williams, p.w. (1989): karst geomorphology and hydrology. chapman & hall, london. foster, s. & van der gun, j. (2016): groundwater governance: key challenges in applying the global framework for action.– hydrogeol. j., 24, 744-752. holland, p. (2014): the dirty dairying campaign and the clean streams accord.– lincoln planning rev., 6, 63-69. julian, j.p., de breues, k.m., owsley, b., davies-colley, r.j. & aussell, a.e. (2017): river water quality changes in new zealand over 26 years: response to land use intensity.– hydrol. earth syst. sci., 21, 1149-1171. mead, d.j. (2015): land use and water quality in te waikoropupu springs. powerpoint presentation to takaka fresh water and land advisory group, tasman district council on 22 may 2015. also available at https://www.researchgate.net/ publication/283939463_land_use_and_water_quality_in_te_waikoropupu_ springs mueller, m. (1991): karst hydrogeology of the takaka valley, golden bay, northwest nelson.n. z. j. geol. and geophys., 34, 11-16. ngāti tama ki te waipounamu trust & yuill, a. (2017): application for a water conservation order in respect of te waikoropupu springs and associated water bodies (including the aquifers, takaka river and tributaries). available at: http://www.mfe.govt.nz/fresh-water/what-government-doing/water-conservation-orders new zealand government (2017): te awa tupua (whanganui river claims settlement) bill. 89 p. available at: http://www.legislation.govt.nz/bill/government/2016/0129/latest/whole.html#dlm6830851 npsfwm (2014): national policy statement for freshwater management 2014 (amended 2017). new zealand government. 47 p. available at: http://www.mfe.govt.nz/ node/23603 richmond, c., froude, v., fenemor, a. & zuur, b. (2004): management and conservation of natural waters.in: harding, j., mosley, p., pearson, c. & sorrell, b. (eds): freshwaters of new zealand.n.z. hydrol. soc. & n.z. liminol. soc., 44.1-44.19. rouse, h.l., norton, n., sinner, j. & vattala, d. (2016): water policy and planning.in: jellyman, p.g., davie, t.j.a., pearson, c.p. & harding, j.s. (eds.): advances in new zealand freshwater science.n.z. freshwater sci. soc. & n.z. hydrol. soc., 663-684. scarsbrook, m., mcintosh, a., wilcox, b. & matthaei, c. (2016): effects of agriculture on water quality.in: jellyman, p.g., davie, t.j.a., pearson, c.p., harding, j.s. (eds.): advances in new zealand freshwater science. n.z. freshwater sci. soc. & n.z. hydrol. soc., 483-503. stewart, m.k. & thomas, j.t. (2008) a conceptual model of flow to the waikoropupū springs, nw nelson, new zealand, based on hydrometric and tracer (18o, cl,3h and cfc) evidence.hydrol. earth syst. sci., 12, 1–19. thomas, j.t. & harvey, m.m. (2013): water resources of the takaka water management area.tasman district council, 38 p. tipa , g., harmsworth, g.r., williams, e. & kitson, j.c. (2016): integrating mātauranga māori into freshwater management, planning and decision-making.in: jellyman, p.g., davie, t.j.a., pearson, c.p. & harding, j.s. (eds.): advances in new zealand freshwater science. n.z. freshwater sci. soc. & n.z. hydrol. soc., 613-637. williams, p.w. (1977): hydrology of the waikoropupu springs: a major tidal karst resurgence in northwest nelson (new zealand).j. hydrol. (netherlands), 35, 73-92. williams, p. (2004): karst systems.– in: harding, j., mosley, p., pearson, c. & sorrell, b. (eds.): freshwaters of new zealand. n.z. hydrol. soc. & n.z. liminol. soc., 31.1-31.20. www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction during the late jurassic, the dasycladales (green algae) flourish­­ed­during­a­period­that­followed­crisis­moments­at­the­ end­of­the­late­triassic­and­the­final­part­of­the­early­jurassic,­ as­ well­ as­ a­ very­ slow­ recovery­ in­ the­ middle­ jurassic­ (granier & deloffre, 1993; bucur, 1999; bucur & reolid,­2024).­in­the­oxfordian–tithonian­interval,­86­ dasycladalean­species­are­known,­72­of­which­are­mentioned­ in­ the­tithonian­ (bucur­&­reolid,­2024).­thirty­ four­ species­continued­their­evolution­into­the­early­cretaceous.­ regarding­the­upper­jurassic­dasycladaleans,­aloisalthella sulcata (alth)­[ex­clypeina jurassica favre,­ex­clypeina sulcata (alth), see granier­&­lethiers, 2019] and salpingoporella pygmaea (gümbel)­are­among­the­most­fre­ quently­encountered­and,­as­such,­the­best­known.­a­special­ place­is­occupied­by­neoteutloporella socialis (praturlon), a­dasycladalean­alga­that­develops­in­the­form­of­"mini­reefs"/ bioherms.­these­are­actually­agglomerations­of­thalli­in­the­ form­of­overlapping­"bushes"­that­can­reach­from­a­few­centi­ metres­to­a­few­decimetres­in­height­and­breadth. the­aim­of­the­present­work­is­to­describe­a­new­dasycla­ dalean alga, schlagintweitella inopinata nov.­gen.,­nov.­sp.,­ which,­like­neoteutloporella,­develops­in­the­form­of­thallus­ agglomerations.­although,­agglomeration­is­not­uncommon­ among­extant­dasycladales,­as­evidenced­by­numerous­recent­ illustrations­of­loose­agglomerations­(e.g.,­tropical­fish­ plus­(2024),­for­neomeris),­none­develops­neoteutloporella­ type­“mini­reefs”. 2. geological background the­mesozoic­deposits­in­the­cioclovina­băniţa­area­(also­ known­as­the­haţeg­pui­area;­fig.­1)­constitute­a­fragment­of­ the­sedimentary­cover­of­the­getic­nappe­(stillă,­1985;­ pleş­et­al.,­2019).­the­sedimentary­succession­of­this­area­ includes­ deposits­ from­ the­ lower­ jurassic­ to­ the­ upper­ schlagintweitella inopinata, a new genus and species of dasycladales (green algae) from the upper jurassic limestones of romania ioan i. bucur1,2,*, emanoil săsăran1, george pleş1 1 babeş-bolyai university, department of geology and center for integrated geological studies, m. kogălniceanu 1, 400084 cluj-napoca, romania; (*corresponding author: ioan.bucur@ubbcluj.ro; emanoil.sasaran@ubbcluj.ro; george.ples@ubbcluj.ro) 2 romanian academy, cluj branch, republicii 9, 400015 cluj-napoca, romania doi: 10.4154/gc.2025.10 abstract an outcrop identified within the upper jurassic deposits of the cioclovina-băniţa area (southern carpathians) most likely corresponds to a cavern fill. in several lithoclasts of this fill, including black-pebbles, a dasycladalean alga with morphological features that differentiate it from all other jurassic–cretaceous dasycladales with two orders of laterals was observed. it is described in the present work as a new species of a new genus: schlagin­ tweitella inopinata nov. gen., nov. sp. cretaceous­ (pre­maastrichtian).­ the­ terrigenous­ lower­ jurassic­ is­ developed­ in­ the­ gresten­ facies.­ the­middle­ jurassic­is­mainly­represented­by­siliciclastic­rocks­followed­ by­a­carbonate­sequence­in­the­upper­part.­the­upper­jurassic­ and­the­lowermost­cretaceous­are­represented­by­carbonate­ rocks­(figs.­1,­2).­although­initially­included­within­an­upper­ jurassic–aptian­carbonate­succession­(stillă,­1985),­the­ barremian–aptian­is­present­only­as­clasts­in­the­conglo­me­ ratic­breccia­deposits­in­the­lower­part­of­the­cenomanian­ (pleș­ et­ al.,­ 2019).­during­ the­albian,­ lateritic­ deposits­ formed,­leading­to­the­accumulation­of­bauxites.­the­upper­ cretaceous­ includes­a­marine­succession­ that­begins­with­ ceno­manian­breccias­and­conglomerates,­and­ends­with­cam­ panian­marls.­these­are­covered­by­the­maastrichtian­conti­ nental­deposits­of­the­haţeg­basin. the­limestones­containing­the­new­dasycladalean­alga­ belong­to­the­upper­jurassic.­the­outcrop­is­located­in­the­ lunca­ohabei­plateau,­near­albian­bauxite­lenses­(fig.­3).­ac­ cording­to­săsăran­et­al.­(2021),­the­outcrop­represents­a­ cavern­fill.­the­clasts­in­the­cavern­fill­originated­from­different­ depositional­environments­and­were­later­transported­into­the­ karst­void.­they­consist­of­bioclasts,­intraclasts,­calcrete­clasts,­ fragments­of­altered­carbonate­ rocks­pigmented­with­ iron­ oxides­hydroxides.­some­of­ these­ represent­black­pebbles­ formed­in­subaerially­exposed­areas­through­impregnation­ with­organic­matter. one­of­ these­clasts­(fig.­4)­ is­mainly­composed­of­an­ agglo­meration­of­algal­thalli.­their­study­revealed­the­dis­co­ very­of­a­new­genus­and­a­new­species­of­dasycladalean­green­ algae. 3. material and repository the­new­alga­was­found­in­two­samples,­from­which­four­thin­ sections­were­made.­additionally,­three­other­samples­were­ collected­from­the­type­locality,­resulting­in­thirteen­thin­ 2025 | 78/2 | 103–113 | 4 figs. | 6 plts. | article history: manuscript received: december 4, 2024 revised manuscript accepted: march 12, 2025 available online: june 3, 2025 keywords: dasycladales, upper jurassic, new genus, new species, romania g eo lo gi a c ro at ic a 104 geologia croatica 78/2 sections­used­for­studying­the­accompanying­micro­palaeonto­ logical­association.­all­thin­sections­are­stored­in­the­collection­ of­the­paleontology­museum­of­babeş­bolyai­university,­cluj­ napoca. 4. palaeontological description phylum­chlorophyta­pascher,­1914 class­ulvophyceae­mattox­&­stewart,­1984 order­dasycladales­pascher,­1931 family­triploporellaceae­(pia,­1920)­berger­&­kaever,­ 1992 tribe­triploporelleae­(pia,­1920)­bassoullet­et­al.,­1979 genus schlagintweitella nov. gen. type­species:­schlagintweitella inopinata­nov.­gen.,­nov.­sp. 1997­dasycladacean­with­unsegmented­primary­ and­ seg­ ment­ed­secondary­laterals­–­de­castro,­p.­200,­pl.­4,­figs.­ 1­3. derivation­of­name:­dedicated­to­dr.­felix­schlagintweit (münchen)­for­his­significant­contributions­to­the­study­of­ mesozoic­and­cenozoic­calcareous­algae. generic diagnosis:­dasycladalean­ algae­with­ cylindrical­ thallus­and­two­orders­of­laterals.­the­primary­laterals­are­ cylindrical­or­ovoid­elon­gated,­shorter­than­the­secondaries.­ the­secondary­laterals­are­also­cylindrical­and­consist­of­two,­ rarely­three­successive­segments­separated­by­constrictions.­ the­proximal­part­of­the­secondary­laterals­is­covered­by­a­ common­calcareous­sheath­(collective­sheath). remarks and comparisons: in­the­jurassic­and­cretaceous­ fossil­record,­29­genera­of­dasy­cladales­with­two­orders­of­ laterals­are­known­(e.g.,­bucur­et­al.,­2010;­table­1;­to­the­ genera­in­this­table­we­must­add­the­genera­steinmanniporella, bakalovaella, eodasy cladus, chinianella, granieria, diste­ fano polia, and cylindro porella? liasica).­ the­ differences­ between­all­these­taxa­are­given­by­the­shape­and­dimensions­ of­the­laterals,­the­diff­eren­ces­in­shape­between­the­first­and­ second­order­laterals,­as­well­as­the­dimen­sional­ratio­between­ the­two­types­of­laterals.­in­addition,­the­type­of­reproduction­ is­considered.­the­genus­linoporella,­with­the­type­species­ linoporella capriotica (oppenheim),­presents­three­orders­ of­ laterals­ and­ thus­ differentiates­ itself­ from­ this­ group­ (barattolo­&­romano,­2005).­we­can­also­add­to­this­ list the genus palaeo dasycladus,­ which­ has­ segmented­ secondary­ laterals,­but­ it­presents­ three­or­more­orders­of­ laterals,­and­thus­differs­from­the­new­genus.­three­of­the­ genera­ mentioned­ in­ table­ 1­ by­ bucur­ et­ al.­ (2010)­ (montenegrella, crinella, and helio porella)­are­most­likely­ recent­synonyms­of­the­genera­suppilu liu maella­(the­first­two)­ and neomeris,­respectively.­of­the­remaining­genera,­those­in­ the­tribe­neomeree­(genotella, montiella/bakalovaella, neo­ meris, and cymopolia)­ are­ distin­guished­ by­ the­ type­ of­ choristospore­reproduction­and/or­by­the­shape­of­the­thallus­ (e.g., cymopolia). conradella, chinia nella, eodasycladus, gra nieria, distefanopolia, and cylindro porella? liasica belong­to­the­same­group­(cf.­barattolo­&­parente,­ 2000;­barattolo­et­al.,­2008,­2012,­2021a).­among­the­ dasy­cladales­ in­ the­ triploporelleae­ tribe,­ acroporella, rajkaella, and triploporella­all­have­much­longer­first­order­ laterals­com­pared­to­second­order­laterals.­dis so cladella (tribe­ dissocla­delleae)­includes­species­with­primary­and­secondary­ laterals­that­are­comparable­in­dimension­but­differ­in­shape.­ selliporella­has­short,­globose­first­order­laterals­and­long,­ trichoform­second­order­laterals­(see­barattolo­et­al.,­ 2021b).­tersella and pseudocymopolia­are­distinguished­by­ the­different­general­morphology­of­the­thallus­(club­shaped,­ very­clearly­differen­tiated­into­head­and­stipe,­and­moniliform,­ respectively). the­new­genus­schlagintweitella­shows­the­greatest­simi­ larity­to­the­genus­neoteutloporella (bassoullet­et­al.,­1978)­ figure 1. a geological map of the cioclovina-băniţa area with the location of the studied section (red star). modified after pleş et al., 2019. g eologia c roatica 105bucur et al.: schlagintweitella inopinata, a new genus and species of dasycladales (green algae) from the upper jurassic limestones of romania de­castro,­1993.­the­genus­neoteutloporella­includes­two­ species,­both­from­the­upper­jurassic:­n. obsoleta­(carozzi,­ 1954)­and­n. socialis­(praturlon,­1963).­both­species­have­ relatively­short,­globose­or­ovoid­first­order­laterals­and­rela­ tively­long,­acrophorous­or­slightly­phloiophorous­second­order­ laterals­ that­ are­ segmented­ by­ several­ constrictions.­both­ species­ occur­ as­ dense­ agglomerations­ of­ thalli,­ often­ in­ overlapping­ generations­ in­ the­ case­ of­n. socialis,­with­ a­ “micro­reef”/bioherm­appearance. from­the­current­material­obtained,­schlagintweitella­nov.­ gen.­also­develops­as­an­agglomeration­of­thalli­(pl.­1,­figs.­ a­c).­however,­it­differs­from­neutloporella by­the­more­elon­ gated­cylindrical­shape­of­the­first­order­laterals­and­acrophore­ type­second­order­laterals,­which­have­rarer­constrictions­and­ often­an­irregular­arrangement.­these­laterals­are­included,­at­ least­in­their­lower­part,­in­a­collective­sheath.­moreover,­the­ skeleton­of­neoteutloporella­is­formed­„by­a­succession­of­very­ wide­articles,­roughly­funnel­shaped”­(de­castro,­1993,­p.­ 174),­and­the­thallus­is­branched. schlagintweitella inopinata nov. sp. pls.­1­5 derivation­of­name:­inopinatus­(latin)­=­unexpected. material:­ four­ thin­sections­from­two­samples,­containing­ more­than­50­specimens. holotype:­the­specimen­in­pl.­2­fig.­a,­thin­section­15207(2),­ stored­in­the­collection­of­the­paleontology­museum,­babeş­ bolyai­university­cluj­napoca­under­the­inventory­number­ 24412. paratypes:­specimens­in­pl.­2­fig.­b,­pl.3,­figs.­e­g,­ thin­ sections­3751(2),­15207(1)­and­3751(1)­stored­in­the­same­col­ lection­under­the­inventory­numbers­24410,­24411­and­24409­ respectivelly. type­locality:­lunca­ohabei­plateau,­cioclovina­băniţa­zone,­ southern­carpathians,­romania­(fig.­1).­gps­coordinates:­ 45°31'35.61"n;­23°­9'55.65"e. type­level:­upper­jurassic,­most­probably­upper­tithonian. diagnosis:­dasycladalean­alga­with­an­elongated­cylindrical­ thallus,­a­relatively­wide­axial­cavity­and­two­orders­of­lateral­ branches­arranged­obliquely­to­the­axial­cavity.­the­first­order­ laterals­are­cylindrical­(acrophores)­or­ovoid­to­elongated­and­ shorter­ than­ those­of­ the­ second­order.­the­ second­order­ laterals­are­also­cylindrical,­acrophorous,­longer­than­those­of­ the­first­order­and­have­one­or­more­constrictions­that­separate­ them­into­successive­segments.­the­calcification­consists­of­a­ calca­reous­sheath­surrounding­the­central­cavity­and­each­ lateral­branch.­in­their­lower­part,­the­second­order­laterals­are­ wrapped­in­a­collective­sheath.­ dimensions­(in­mm,­except­w1­and­w2) d­(external­diameter)­=­1.30–2.60­(median­=­1.97) d­(internal­diameter)­=­0.50–1.70­mm­(median­=­1.05­mm) p1­(diameter­of­the­primary­laterals)­=­0.06–0.12­mm­(median­ =­0.09­mm) l1­(length­of­the­primary­laterals)­=­0.13–0.30­mm­(median­=­ 0.19­mm) p2 (diameter­of­the­secondary­laterals)­=­0.05–0.10­mm­(median­ =­0.06­mm) l2­(length­of­the­secondary­laterals)­=­0.28–0.60­mm­(median­ =­0.41­mm) h­(distance­between­two­consecutive­verticils)­=­0.10–0.15­ (median­=­0.13) w1­(number­of­primary­laterals­in­a­verticil)­=­approx.­25­to­60 w2­(number­of­secondary­laterals­per­primary­lateral)­=­2–3 description:­the­new­alga­occurs­as­agglomerations­of­thalli­ within­cal­careous­clasts­or­black­pebbles­(pl.­1,­figs.­a–c).­ longitudinal­and­longitudinal­oblique­sections­(pl.­2,­figs.­ a–e)­show­a­cylindrical­thallus,­sometimes­slightly­curved­ (pl.­2a),­with­a­relatively­smooth­axial­cavity­and­a­rather­ irregular­external­surface,­marked­by­the­different­lengths­(and­ some­times­different­orientations)­of­the­secondary­laterals.­ these­features­are­also­visible­in­oblique­or­oblique­longitudinal­ figure 2. the general stratigraphic succession of the jurassic and cretaceous deposits from the cioclovina-băniţa area (modified from pleş et al., 2019). the arrow points to the stratigraphic position of the outcrop with the new alga. g eo lo gi a c ro at ic a 106 geologia croatica 78/2 sections­(pl.­3,­figs.­a–i;­pl.­4,­figs.­c,­i,­j)­and­in­transverse­ sections­(pl.­2,­fig.­f;­pl.­4.,­figs.­a,­b,­d,­g,­h).­the­primary­ laterals­are­tubular­(most­often­cylindrical;­e.g.,­pl.­3,­figs.­c­f;­ sometimes­they­are­ovoid­elongated,­e.g.,­pl.­5,­fig.­c).­the­ primary­laterals­are­provided­at­the­lower­part­with­a­relatively­ wide­pore­that­connects­them­with­the­axial­cavity.­from­the­ primary­ laterals­ two­(sometimes­ three)­secondary­ laterals­ originate­that­are­also­cylindrical­(acrophorous)­(pl.­5,­figs.­a,­ g,­i)­and­present­at­certain­intervals­constrictions­that­separate­ them­into­successive­segments­delimited­by­a­fine­micritic­ fringe­(pl.­5,­figs.­a,­d,­e,­arrows).­the­large­number­of­late­ rals­in­a­whorl­makes­it­difficult­to­observe­their­arrangement­ around­and­along­the­axial­cavity.­however,­some­sections­ through­smaller­specimens­(e.g.,­pl.­3,­figs.­e­g;­pl.­4,­figs.­d,­ h,­j),­where­the­thallus­is­tangentially­obliquely­sectioned,­ indicate­a­euspondyl­arrangement.­the­secondary­laterals,­ however,­occasionally­seem­to­orient­themselves­in­various­ directions­(pl.­3,­figs.­c,­d,­f),­giving­an­irregular­appearance­ to­the­external­part­of­the­thallus.­the­calcification­consists­of­ a­calcareous­sheath,­observable­in­some­places­around­the­ axial­cavity­(pl.­2,­figs.­a,­f;­pl.­3,­figs.­a,­f,­h,­i;­pl.­4,­figs.­ b,­h),­but­especially­around­the­laterals,­being­clearly­visible­ where­the­laterals­are­sectioned­more­or­less­transversely­(pl.­ 2,­fig.­b­–­lower­part;­pl.­3,­figs.­a,­d­i;­pl.­4,­fig.­g).­one­of­ the­important­characteristics­of­the­new­alga­is­the­presence­ of­ a­ common­ calcareous­ sheath­ (collective­ sheath­ cf.­de­ castro,­1997)­that­envelops­the­proximal­part­of­the­secon­ dary­laterals­(e.g.,­pl.­2,­fig.­g;­pl.­4,­figs.­e,­j;­pl.­5,­figs.­h,­j).­ the­term­collective­sheath­introduced­by­de­castro­(1997)­ was­illustrated­by­this­author­in­pl.­4,­figs.­1–3­through­two­ specimens­ of­ an­ alga­ defined­ as­ "dasycladacean­ with­ unsegmented­primary­and­segmented­secondary­laterals"­and­ which­actually­represents­the­first­illustration­in­the­literature­ of­schlagintweitela inopinata­nov.­gen.,­nov.­sp.­it­is­worth­ mentioning­that­while­some­specimens­present­a­calcareous­ sheath­of­sparitic­calcite­(pl.­3,­fig.­g;­pl.­4,­figs.­d,­f,­g;­pl.­5,­ fig.­h),­sometimes­with­a­yellowish­brown­tint­(pl.­3,­fig.­b;­ pl.­4,­figs.­e,­h,­j;­pl.­5,­fig.­j),­most­specimens­have­a­strongly­ blackened­sheath­due,­most­ likely,­ to­ the­accumulation­of­ organic­matter­during­the­blackening­process­that­affected­the­ black­pebbles­ in­which­ they­ are­ contained.­reproductive­ structures­were­not­encountered,­but­their­presence­in­the­first­ order­laterals­cannot­be­excluded­(cladospore). comparison:­within­the­large­group­of­jurassic–cretaceous­ dasycladales­with­ two­orders­of­ laterals,­schlaginweitella inopoinata­nov.­gen.,­nov.­sp.­is­most­­similar­to­species­of­the­ genus neoteut loporella (n. obsoleta and n. socialis)­and­with­ some­species­of­the­genus­steinmanniporella (e.g., s. kapelen sis, s. taurica).­it­differs­from­neoteutloporella­by­the­shape­and­ dimensional­ratio­of­the­primary­and­secondary­laterals,­as­ well­as­the­lack­of­articulation.­it­differs­from­steinmanniporella by­the­seg­men­tation­of­the­secondary­laterals. associated microfossils: in­ the­ outcrop­ from­ the­ lunca­ ohabei­plateau,­schlagintweitella inopinata­nov.­gen.,­nov.­sp.­ is­accompanied­by­an­assemblage­of­foraminifera­and­cal­­ careous­ algae­ consisting­ of:­everti cyclammina virguliana (koechlin), everticyclammina­sp.,­redmondoides lugeoni (septfontaine), charentia­sp.,­coscinoconus alpinus leupold­ (pl.­ 6,­ figs.­ g,­ i),­ salpingo porella annulata (carozzi)­ (pl.­ 6,­ figs.­a–d),­salpingopo rella pygmaea (gümbel)­(pl.­6,­figs.­e–f),­s.­cf.­praturloni (dragastan), aloisalthella sulcata (alth)­ (pl.­6,­fig.­ j),­campbelliella striata (carozzi),­and­ rivulariacean­like­cyanobacteria.­ figure 3. the outcrop from the lunca ohabei plateau (cioclovina-băniţa zone) representing most probably a palaeo-cave filling where the sample with schlagintweitella inopinata nov. gen., nov. sp. has been found. figure 4. a pebble of the cave filling showing the new alga on a weathered surface. g eologia c roatica 107bucur et al.: schlagintweitella inopinata, a new genus and species of dasycladales (green algae) from the upper jurassic limestones of romania some­of­the­microfossils­in­this­association­are­coloured­with­ a­light­brown­tint,­likely­due­to­the­partial­incor­poration­of­ organic­matter.­the­entire­association­indicates­a­late­jurassic­ age,­most­likely­late­tithonian. 5. conclusion a­new­dasycladalean­alga,­schlaginweitella inopinata­nov.­ gen.,­nov.­sp.­was­identified­in­the­upper­jurassic­limestones­ of­the­cioclovina­băniţa­area­(southern­carpathians,­roma­ nia).­by­its­morphological­characteristics,­the­new­alga­differs­ from­all­other­genera­ and­ species­of­ jurassic–cretaceous­ dasy­cladales­with­two­orders­of­laterals. acknowledgement we­thank­bruno­granier­(brest)­and­marc­a.­conrad­(geneve)­ for­their­remarks­and­suggested­corrections. references barattolo,­f.­&­parente,­m.­(2000):­new­observations­on­uragiella liasica (lebouché­&­lemoine)­(green­algae,­dasydadales)­from­ the­type­locality­(canders,­languedoc­–­southern­france).–­bollettino­ della­societa­paleontologica­italiana, 39/2,­123–137. barattolo,­f.­&­romano,­r.­(2005):­shallow­carbonate­platform­bio­ events­during­the­upper­triassic–lower­jurassic:­an­evolutive­interpre­ tation.–­italian­journal­of­geosciences,­124/1,­123­142. barattolo,­f.,­granier,­b.,­romano,­r.­&­ferré,­b.­(2008):­pe­ trascula iberica (dragastan­&­trappe), tersella genotii ba­ rattolo­&­bigozzi,­and­the­relationships­of­club­shaped­dasycla­ dalean­ algae­ during­late­triassic–early­ jurassic­ times.–­geologia­ croatica­61,­159–176.­https://doi.org/10.4154/gc.2008.15 barattolo,­f.,­parvanech­nejad­shirazi,­m.­&­vecchio,­e.­ (2012):­the­genus­eodasycladus­(lower­jurassic­dasycladalean­green­ alga)­and­its­relationship­with­palaeodasycladus.–­facies,­58/3,­445­455.­ https://doi.org/10.1007/s10347­012­0304­6. barattolo,­f.,­romano,­r.­&­conrad,­m.­(2021a):­evidence­of­ex­ ternal­gametophores­in­puzzling­late­triassic–early­jurassic­dasyclad­ alean­green­algae.–­acta­palaeontologica­polonica,­66/4,­901–919.­https:// doi.org/10.4202/app.00883.2021. barattolo,­f.,­amodio,­s.,­bucur,­i.i.­&­martino,­m.­(2021b):­se­ lliporella johnsonii (praturlon)­nov.comb.­and­selliporella neoco­ miensis (radoičić)­(green­algae,­dasycladales),­taxonomic­reconsi­ deration­and­chronostratigraphic­calibration.–­cretaceous­research,­125,­ 104848.­https://doi.org/10.1016/j.cretres.2021.104848 bassoullet,­j.­p.,­bernier,­p.,­conrad,­m.­a.,­deloffre,­r.­&­ jaffrezo,­m.­(1978):­les­algues­dasycladales­du­jurassique­et­du­ crétacé.–­geobios:­mémories­spécial, 2,­330­p. bassoullet,­j.­p.,­bernier,­p.,­deloffre,­r.,­génot,­p.,­jaffre­ zo,­m.­&­vachard,­d.­(1979):­essai­de­classification­des­dasyclada­ les­en­tribus.–­bulletin­des­centres­de­recherche­exploration­–­produ­ ction­elf­aquitaine,­3/2,­429­442. berger,­s.­&­kaever,­m.j.­(1992):­dasycladales:­an­illustrated­mono­ graph­of­a­fascinating­algal­order.–­thieme,­stuttgart,­247­p. bucur,­i.i.­(1999):­stratigraphic­significance­of­some­skeletal­algae­(dasyc­ ladales,­caulerpales)­of­the­phanerozoic.–­in:­farinacci,­a.­&­lord,­ a.r.­(eds.):­depositional­episodes­and­bioevents.­palaeopelagos­special­ publication,­2,­53–104. bucur,­i.i.­&­reolid,­m.­(2024):­incidence­of­the­early­toarcian­global­ change­on­dasycladales­(chlorophyta)­and­the­subsequent­recovery:­ comparison­with­end­triassic­mass­extinction.–­earth­science­reviews,­ 249,­104666.­https://doi.org/10.1016/j.earscirev.2023.104666. bucur,­i.i.,­granier,­b.­&­schlagintweit,­f.­(2010):­steinmanni­ porella, a­new­dasycladale­genus­name­for­“linoporella”­with­two­orders­ of­ laterals.–­facies­56,­317–321.­https://doi.org.­10.1007/s10347­009­ 0206­4. carozzi,­a.­(1954):­survivance­du­genre­teutloporella dans le jurassique supérieur­récifal­du­grande­salève.–­archives­des­sciences,­7/4,­219– 324. de­castro,­p.­(1993):­observations­on­campbeliella, radoičić,­1959­ and neoteutloporella, bassoullet­et­al.,­1978­(green­algae,­dasyc­ ladales).–­in:­barattolo,­f.,­de­castro,­p.­&­parente,­m.­ (eds.):­studies­on­fossil­benthic­algae.–­bollettino­della­societa­paleon­ tologica­italiana,­special­volume,­1,­121–184. de­castro,­p.­(1997):­introduzione­allo­studio­in­sezione­sottile­delle­da­ icladali­fossili­[an approach to thin­section study of fossil dasycladales –­in­italian].–­quaderni­dell’accademia­pontaniana,­22,­261­p. granier,­b.­&­deloffre,­r.­(1993):­inventaire­critiques­des­algues­da­ sycladales­fossiles.­iie­partie­–­les­algues­dasycladales­du­jurassique­et­ du­crétacé.–­revue­de­paléobiologie,­12/1,­19–65. granier,­b.­&­lethiers,­a.­(2019):­aloisalthella,­a­new­genus­of­fossil­ polyphysacean­green­algae­(chlorophyta,­dasycladales),­with­notes­on­ the genus clypeina­ (michelin,­ 1845).–­palaeontologia­electronica,­ 22.2.45a,­1–20.­http://doi.org/10.26879/923 mattox,­k.r.­&­stewart,­k.d.­(1984):­classification­of­the­green­al­ gae:­a­concept­based­on­comparative­cytology.–­in:­irvine,­d.e.g.­&­ john,­d.­(eds.):­systematics­of­the­green­algae.­academic­press,­lon­ don,­29–72. pascher,­a.­(1914):­über­flagellaten­und­algen.–­berichte­der­deutschen­ botanischen­gesellschaft,­32,­136–160. pascher,­a.­(1931):­systematische­übersicht­über­die­mit­flagellaten­in­ zusammenhang­stehenden­algenreihen­und­versuch­einer­einreihung­ dieser­algenstämme­in­die­stämme­des­pflanzenreiches.–­beihefte­zum­ botanischen­centralblatt,­48,­317–332. pia­j.­(1920):­die­siphoneae­verticillatae­vom­karbon­bis­zur­kreide.–­ab­ handlungen­der­zoologisch­botanischen­gesellschaft­in­wien,­wien,­ 11/2,­263­p. pleş,­g.,­oprişa,­a.,­bucur,­i.i.,­săsăran,­e.,­mircescu,­c.v.,­ol­ tean,­g.­&­iacob,­r.g.­(2019):­the­central­western­getic­carbonate­ platform:­upper­jurassic­to­lower­cretaceous­biostratigraphy­and­sedi­ mentary­evolution­of­the­cioclovina–băniţa­sector­(southern­carpat­ hians,­romania).–­facies,­65,­32.­https://doi.org/10.1007/s10347­019­ 0574­3 praturlon,­a.­(1963):­una­nuova­teutloporella (alga calcarea) nel giure­ se­superiore­di­m.­corno­(parco­nazionale­di­abruzze).–­geologica­ro­ mana,­2,­199–206. săsăran,­e.,­cîntă­pânzaru,­s.,­pleş,­g.,­bucur,­i.i.,­săsăran,­ l.,­tămaş,­t.,­mircescu,­c.­&­oprişa,­a.­(2021):­upper­jurassic­ cave­filling,­a­case­study.–­in:­abstracts­of­the­scientific­session­„ion­ popescu­voiteşti”,­cluj­university­press,­cluj­napoca,­24­p. stillă,­a.­(1985):­géologie­de­la­région­de­haţeg­cioclovina­pui­băniţa­ (carpathes­méridionales)­[geology of the haţeg-cioclovina-pui-băniţa –­in­romanian].–­annuaire­de­l’institut­de­geologie­er­geophysique,­66,­ 91–179. web sources: tropical­fish­plus­(2024):­neomeris.­available­at:­https://­tropicalfi­ shplus.com/products/neomeris.­accessed­on:­december­1st,­2024. https://doi.org/10.1016/j.earscirev.2023.104666 https://doi.org/10.1007/s10347-019-0574-3 https://doi.org/10.1007/s10347-019-0574-3 g eo lo gi a c ro at ic a 108 geologia croatica 78/2 plate 1. a–c general views of an agglomeration of thalli of schlagintweitella inopinata nov. gen., nov. sp. thin-sections: a, 3751(1); b, 3751(2); c, 15207(1). g eologia c roatica 109bucur et al.: schlagintweitella inopinata, a new genus and species of dasycladales (green algae) from the upper jurassic limestones of romania plate 2. schlagintweitella inopinata nov. gen., nov. sp. a–e longitudinal (a) and longitudinal oblique (b–f) sections. a = holotype; b = paratype; f = transverse section. thin-sections: a, d-f, 15207(2); b, 3751(2); c, 15207(1). g eo lo gi a c ro at ic a 110 geologia croatica 78/2 plate 3. a-i schlagintweitella inopinata nov. gen., nov. sp., oblique sections. e and g, paratypes. thin-sections: a, c-f, h-i, 15207(1); b, 3751(2); g, 3751(1). g eologia c roatica 111bucur et al.: schlagintweitella inopinata, a new genus and species of dasycladales (green algae) from the upper jurassic limestones of romania plate 4. schlagintweitella inopinata nov. gen., nov. sp. a, b, d, g transverse sections. c, f, h-j oblique sections. e is a close-up view of the lower part of j. thin-sections: a-c, h-i, 15207(1); d-g, j, 3751(2). g eo lo gi a c ro at ic a 112 geologia croatica 78/2 plate 5. schlagintweitella inopinata nov. gen., nov. sp. a-j details of laterals, showing the primary (r1) and the secondary laterals (r2). the arrows in a, d and e point to the constrictions separating segments inside the secondary laterals. the arrows in h and j point to the collective sheath around the secondary laterals. thin-sections: a, d-g, i-j, 15207(1); b, 15207(2); c, 3751(2); h, 3751(1). g eologia c roatica 113bucur et al.: schlagintweitella inopinata, a new genus and species of dasycladales (green algae) from the upper jurassic limestones of romania plate 6. microfossils associated with schlagintweitella inopinata nov. gen., nov. sp. a-d salpingoporella annulata (carozzi); e-f salpingoporella pygmaea (gümbel); h frentzenella involuta (mantsurova); g-i coscinoconus alpinus leupold. j aloisalthella sulcata (alth). thin-sections: a, 3747(2); b-d, g-i, 3767; e, 3751(9); f, 3751(6); j, 3747(5). www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2024 | 77/3 | 311–323 | 6 figs. | 7 tabs. | 1 supplement | 1. introduction weathering is a complex set of processes occurring at or near the earth’s surface, resulting in physical and chemical rock alteration. it involves processes that span many orders of magnitude in spatial and temporal scales (frings & buss, 2019), so consequently the meaning of “weathering” may be dependent on the standpoint, which leads to the need of its precise definition (hall et al., 2012). in this study, the term is used for parent material alteration (relating to the chemical composition) and secondary mineral formation in response to environmental factors, dominantly climate. apart from climate, dictating the weathering rate and intensity, parent material composition sets the “starting position” and is the dominant influence on the secondary weathering products, especially in the early stages of weathering. in this case, studying the profiles in a temperate climate region formed on different parent materials, both of these factors are taken into account. the use of (clay) minerals and geochemical signatures in studies of past weathering conditions has gained traction in the research of the critical zone, defined by banwart et al. (2012) as the terrestrial environment extending from the top the influence of weathering and pedogenesis on the geochemical record of miocene marls and plio-quaternary sediments, medvednica mt., croatia zvonka gverić1,*, nenad tomašić1, goran durn2 and vedran rubinić3 1 university of zagreb, faculty of science, department of geology, horvatovac 95, 10000 zagreb, croatia; (*corresponding author: zgveric@geol.pmf.hr) 2 university of zagreb, faculty of mining, geology and petroleum engineering, department of mineralogy, petrology and mineral resources, pierottijeva 6, 10000 zagreb, croatia 3 university of zagreb, faculty of agriculture, department of soil science, svetošimunska 25, 10000 zagreb, croatia doi: 10.4154/gc.2024.17 abstract the geochemical signature of weathering and pedogenesis in a temperate humid climate on two parent material types in the foothills of medvednica mt. was studied. five soil profiles on miocene marls and three sections of plio-quaternary (plq) proluvial sediments with overlying soil and weathered material were analyzed. the (clay) mineralogy of all profiles and sections had been determined in previous studies. the chemical composition of the samples was determined by inductively coupled plasma emission spectroscopy (icp-oes) and inductively coupled plasma mass spectroscopy (icp-ms). poorly ordered fe and mn oxides were determined in the plq sediment and overlying soil samples by atomic absorption spectroscopy (aas), after oxalate dissolution in the dark. the concentrations and element ratios were used to determine element enrichment/mobility and intensity of chemical weathering, material provenance, and to compare the geochemical signatures with previously obtained clay mineralogy results. trace elements in the miocene marls, including rare earth elements (ree), indicate the continental origin of the marl siliciclastic component, while more scattered geochemical data of the plq sediments reflect their proluvial/torrential nature. the mass transfer coefficient (τ) for major elements and element ratios of the miocene marl profiles indicate chemical weathering and pedogenesis of lower intensity. the geochemistry of these samples shows homogeneity within the profiles. in the geochemical signature of the plq sections, a chaotic proluvial deposition of the material is visible, as well as the heterogeneity with the overlying soil and weathered material. overall, the geochemistry results largely support the clay mineralogy of the samples and demonstrate how a multiproxy approach can help test hypotheses about past environments and provide valuable additional information for complex paleoenvironmental studies. of the vegetation canopy to the bottom of drinking water aquifers, in the past few decades (e.g., godoy et al., 2017; zollinger et al., 2017; dinis et al., 2020; błażejowski et al., 2023; corentin et al., 2023). clay minerals forming as secondary minerals in equilibrium with the prevalent environmental conditions serve as useful proxies for paleo­ environmental studies. the problem arises when clay minerals in recycled material undergo multiple weathering cycles, thus overwriting the past or misrepresenting more recent weathering processes. geochemical signatures, even though also prone to the same issues, can give an additional insight and contribute to the multiproxy approach needed in this type of studies. for this reason, geochemical analyses were included for samples where the clay mineralogy had already been analyzed. the reasoning behind adding another proxy, was the possibility of confirming or refuting conclusions drawn on the basis of mineralogical data. this paper focuses on the effect of weathering (and pedogenesis) on the sediments of the se slopes of medvednica mt., located north of the city of zagreb in croatia (fig. 1), i.e. in the sw part of the pannonian basin system (pbs). while article history: manuscript received: january 10, 2024 revised manuscript accepted: july 16, 2024 available online: october 28, 2024 keywords: geochemical weathering indices, temperate climate weathering, sediment provenance, pedogenesis geochemical signature, miocene marls, plio-quaternary proluvial sediments g eo lo gi a c ro at ic a 312 geologia croatica 77/3 the majority of the paleoenvironmental studies of the pbs so far have used sedimentological, paleontological and palyno lo­ gical proxies (for instance, bakrač & koch, 1999; bakrač et al., 2012), harzhauser et al. (2023) have included clay mineralogy and geochemical records alongside paleontological data to study changes in the paleoenvironment of the vienna basin during the late miocene. several papers on samples and soils from medvednica mt. and the adjacent areas have used (clay) mineralogy and/or geochemical records (e.g., galović & peh, 2014; grizelj et al., 2017; kurečić et al., 2021), but mostly in terms of provenance determination, defining the sedi­ mentary environ ment, or evaluating the influence of the parent material on the soil profiles. geo che mical data in the context of the weathering effect on the rocks and sediments of this area have, to the authors’ knowledge, not been as thoroughly con­ sidered. the benefits of this location, aside from its lithological variety, is its position in the temperate climate zone, where transient and intermediate steps of the weathering process can be studied and the effect of small changes in weathering intensity can be seen in the mineralogy and geochemistry. the clay mineralogy of the samples used in this study had been previously investigated (gverić et al., 2022, 2023). the profiles selected for the above­mentioned studies were developed on the miocene marls (ranging in age from early to late miocene) and plio­quaternary (plq) proluvial, molasse­ type, sediments, both of which are common soil parent materials in the study area. clay mineralogy of the studied miocene marls bedrock and the overlying soil indicates less intense weathering, also dictated by increased ph values due to the presence of carbonates. clay mineralogy of the marl parent material is dominated by smectite­rich illite­smectite and contains illite, kaolinite and sometimes chlorite. changes in clay mineralogy between the parent material and soil are subtle, visible in the appearance of transient mixed­layered phases including chlorite­vermiculite and possibly hydroxyl or organic interlayering of the expandable clay minerals in the soil profile (gverić et al., 2022). in contrast, the clay mine­ ralogy of the plq sediments (analyzed in gverić et al., 2023) consists of more clay mineral species typical of hot and humid areas (kaolinite, low­charge expandables), in addition to the presence of al (oxy)hydroxides. most of the plq sediments are covered with more recent proluvial material, while some are covered with older wind­blown material (loess). this loess cover is thin and usually completely degraded into a pseudo­ gleyed loess derivate, on which stagnosols are formed. the clay mineralogy of this overlying material and soil contains expandable clay minerals of higher layer charge and inter­ mediary clay phases, such as hydroxyl­interlayered minerals, suggesting moderate recent and current weathering conditions. the main aim of this paper is to investigate whether the geochemical records of the investigated miocene and plq sec­ tions are consistent with the composition of the clay mineralogy, i.e. with the intensity of weathering and pedogenesis inferred from the clay mineralogy. if this is the case, it would support our previous conclusions and confirm the key role of soil/sedi­ ment geochemistry together with clay minerals assemblage, in the multidisciplinary study of weathering in relation to (paleo)environmental conditions. 2. study area medvednica mt. is one of the inselbergs in the southwestern part of the pbs, consisting of exposed metamorphosed and non­metamorphosed sediments of paleozoic to mesozoic age, as well as of some mesozoic volcanics, all surrounded by miocene sediments (šikić et al., 1978; basch, 1981; tomljenović et al., 2008; croatian geological survey, 2009; van gelder et al., 2015). the pbs was formed during miocene extension as a back­arc basin and its sedimentary succession is characterized by the changing tectonic environment (pavelić & kovačić, 2018). early miocene sedimentation was dominantly continental with fluvio ­lacustrine sedimentation processes. previous prove­ nance research by kovačić et al. (2011) indicates that the material originated mainly from the inner dinarides during the early and middle miocene, while the upper miocene clastic detritus is mainly of alpine­carpathian provenance. plq sediments on medvednica mt. were deposited pre­ dominant ly as unsorted, molasse type fluvial and proluvial sediments with material sourced locally from the older medved nica mt. lithology (šikić, 1995). based on the sedimentological and paleontological record, the early miocene climate was semi­dry (pavelić et al., 2016) and it became progressively warmer and more humid in the middle miocene (marković et al., 2021). after another dry cycle in the middle miocene (jiménez­moreno et al., 2005), the late miocene climate became very humid and warm before cooling towards the end of the period (harzhauser et al., 2007). during the pliocene, the climate was still warmer than the present day, especially during the mid­pliocene warm period (prista et al., 2015; szabó et al., 2022), but it became subsequently colder and drier. the quaternary is marked by glaciation intervals in the pleistocene as well as coeval loess deposition (rubinić et al., 2018). the present day climate of the area is temperate humid (cfwbx in köppen classification), with a mean annual air temperature of 10°c and mean annual precipitation of 1000­1100 mm, and no distinct dry period (zaninović et al., 2008). vegetation cover, anthropologically substantially modified, mostly varies from deciduous forest comprising beech, hornbeam and oak (natural cover) to orchards and grassland. medvednica mt. is currently 1033 m high, with the mountain’s main ridge stretching in a sw­ne direction and it is divided into three distinct orographic units. due to young tectonic movements and denudation processes, the landscape is intersected by a number of streams and valleys extending from the central massif to the foothills, perpendicular to the direction of the mountain’s line of extension (fig. 1). it is a moderately to markedly dissected hilly and mountainous relief with rather versatile sloping, which can be very steep in places with the occurrence of landslides (lozić, 2001; mihalić arbanas et al., 2016). accordingly, the soils of the studied profiles are mostly thin (e.g., leptosols and regosols); however, some more developed soils, such as cambisols and stagnosols, also occur (gverić et al., 2022, 2023). in the study of parent material influence on soil properties on medvednica mt., spanning different lithologies, perković et al. (2017) iden­ tified dystric cambisol, eutric cambisol, calcaric cambisol, stagnosol, regosol and luvisol. g eologia c roatica 313gverić et al.: the influence of weathering and pedogenesis on the geochemical record of miocene marls and plio-quaternary sediments ... 3. materials and methods a total of 25 samples from 8 locations were studied (table 1, fig. 1). however, due to differences in parent material and sampling strategies, the samples are divided into two distinct groups: profiles developed on the miocene marls and soil sections overlying plq sediments. as a result, the data for the two groups of samples were, in some cases, treated differently to account for the differences between them. 3.1. miocene marl and argillaceous limestone profiles: description and analytical methods the (clay) mineralogy of these samples, along with selected physical and chemical properties, has already been presented in gverić et al. (2022). five soil profiles are developed on miocene marly sediments, with clay mineral content dominated by smectite­rich illite­smectite and containing illite, kaolinite and minor vermiculite. chlorite is detected only in some parent material samples. soil profiles overlying this parent material are poorly to moderately developed and there is no lithic discontinuity present. the texture class of miocene marls and the overlying soil samples is mainly silt loam and subordinately silt clay loam, the samples are calcareous throughout with phh2o values ranging from 7.6 to 8.4 and the chemical composition is dominated by si, al and ca (gverić et al., 2022). the chemical composition of the miocene marl profiles samples (table 2) was determined in the bureau veritas (acme analytical laboratories), in vancouver, bc, canada, using icp­oes and icp­ms after sample fusion with lithium metaborate as well as sample digestion in aqua regia for trace elements (e.g., sc and th used in provenance analysis). 3.2. plq sections: description and analytical methods another three locations are located on plq sediments overlain by weathered material and soil (at some locations genetically unrelated, i.e. interrupted by a lithic discontinuity), with the clay mineralogy dominated by expandable clay minerals (smectite and/or vermiculite) and containing some illite and kaolinite, as well as mixed­layer and hydroxyl­interlayered figure 1. the geographical position of the sample locations and local lithology (blue lines show recent drainage directions (streams) on the se slopes of medvednica mt.); modified after tomljenović (2002). lzb – laz bistrički, čuč – čučerje, mtr – markuševečka trnava, fur – furdini, jes – jesenovec, dot – dotrščina, opo – oporovec, h2 – horvatovac borehole. g eo lo gi a c ro at ic a 314 geologia croatica 77/3 table 1. investigated samples and their clay mineralogy; fe/al oxides are included if present. location sample label and depth in cm sample type clay minerals and fe/al oxides present in the samples m io ce ne p ro fil es laz bistrički n 45.957769 e 16.090546 lzb 0-10 soil i-s, i, v, k, ch-v* lzb 10-30 soil i-s, i, v, k* lzb 30-50 marl i-s, i, v, k* čučerje n 45.894835 e 16.063706 čuč 0-20 soil i-s, i, k, im?* čuč 200 marl i-s, i, k* markuševečka trnava n 45.880720 e 16.023345 mtr 0-20 soil i-s, i, v, k, ch-v/im?* mtr 35-40 marl i-s, i, v, k* mtr 150 marl i-s, i, v, k, ch* furdini n 45.872790 e 16.076558 fur 0-20 soil i-s, i, v, k, ch-v?* fur 20-60 soil i-s, i, v, k, ch-v?* fur 70 argillaceous limestone i-s, i, v, k, ch* jesenovec n 45.92005 e 16.14435 jes 0-20 soil i-s, i, v, k, ch, ch-v?* jes 20-40 soil i-s, i, v, k, ch, ch-v?* jes 40-90 soil i-s, i, v, k, ch, ch-v?* jes 220 marl i-s, i, v, k, ch* pl q s ec tio ns dotrščina n 45.86028 e 16.01972 dot 25 soil v, k, him** dot 120 soil v, s, i, k, ch-v/s?** dot 300 (proluvial) sediment v, s, i, k, gth, gbs, hem** oporovec n 45.84974 e 16.07052 opo 25 soil s, v, k, i, ch-v?** opo 40 soil s, k, i** opo 70 (proluvial) sediment s, k, i, v** horvatovac (borehole) n 45.825910 e 15.987865 h2 25 soil s, k, i, him, gth,** h2 70 soil him, k, i, gth** h2 150 (proluvial) sediment s, k, i, v** h2 250 (proluvial) sediment s, k, i, gth** i-s: illite-smectite, i: illite, v: vermiculite, k: kaolinite, ch-v: interstratified chlorite-vermiculite, im: interlayered clay mineral in which the types of interlayering were not recognized with certainty, ch: chlorite, him: hydroxy-interlayered mineral, s: smectite, ch-v/s: interstratified chlorite-expandable clay mineral, gth: goethite, gbs: gibbsite, hem: hematite. *data from gverić et al. (2022) **data from gverić et al. (2023) table 2. concentrations of major elements (in %) of the samples (from previous studies). sample sio2 al2o3 fe2o3 mgo cao na2o k2o tio2 p2o5 mno cr2o3 loi sum reference m io ce ne p ro fil es lzb 0-10 28.91 8.12 3.83 2.08 25.78 0.27 1.38 0.35 0.12 0.09 0.025 28.8 99.76 g ve ri ć et a l., 2 02 2 lzb 10-30 26.93 8.3 3.91 2.2 27.4 0.27 1.49 0.36 0.07 0.08 0.04 28.7 99.75 lzb 30-50 23.97 7.3 3.04 2.26 30.56 0.26 1.33 0.33 0.08 0.08 0.017 30.6 99.83 čuč 0-20 23.39 4.95 2.07 0.81 28.28 0.32 0.82 0.25 0.2 0.05 0.006 38.6 99.75 čuč 200 16.31 3.6 1.31 0.73 40.59 0.24 0.69 0.18 0.12 0.04 0.005 35.9 99.72 mtr 0-20 52.46 15.14 6.76 1.44 3.99 0.76 1.8 0.87 0.11 0.09 0.016 16.4 99.84 mtr 35-40 20.78 5.74 2.43 1.73 34.58 0.3 0.88 0.28 0.09 0.04 0.006 33 99.86 mtr 150 22.34 5.82 2.34 2.2 33.79 0.3 0.91 0.29 0.1 0.04 0.006 31.7 99.84 fur 0-20 45.04 14.83 5.97 1.57 9.03 0.6 2.19 0.72 0.12 0.11 0.015 19.6 99.80 fur 20-60 25.05 8.51 3.25 1.41 29.54 0.33 1.4 0.35 0.09 0.07 0.009 29.8 99.81 fur 70 26.64 8.38 3.31 1.7 27.46 0.4 1.32 0.36 0.09 0.08 0.009 30.1 99.85 jes 0-20 38.66 12.53 4.73 3.93 13.18 0.81 2.33 0.59 0.14 0.08 0.012 22.8 99.79 jes 20-40 42.48 13.85 4.84 4.04 12.56 0.91 2.48 0.64 0.11 0.07 0.014 17.8 99.79 jes 40-90 41.01 13.82 5.39 3.69 13.9 0.92 2.51 0.6 0.11 0.08 0.013 17.7 99.74 jes 220 47.82 15.16 5.18 4.69 7.56 1.07 2.86 0.7 0.12 0.07 0.015 14.5 99.75 pl q s ec tio ns dot 25 68.58 12.75 3.82 0.81 0.47 1.20 1.54 1.26 0.10 0.13 0.01 6.2 96.90 g ve ri ć et a l., 2 02 3 dot 120 61.75 14.00 6.01 1.09 0.51 1.00 1.79 1.11 0.12 0.47 0.01 6.2 94.07 dot 300 54.91 16.12 6.62 1.66 1.58 1.58 1.22 1.37 0.12 0.01 0.02 9.2 94.42 opo 25 66.53 12.94 3.86 0.59 0.29 0.90 1.61 1.20 0.08 0.05 0.01 6.8 94.87 opo 40 61.75 14.89 4.82 0.73 0.34 0.69 1.70 1.11 0.06 0.05 0.01 7.4 93.55 opo 70 59.24 16.80 5.16 1.20 0.47 0.60 1.95 1.00 0.08 0.08 0.01 9.2 95.78 h2 25 64.71 14.43 5.57 1.01 0.67 1.09 1.78 1.19 0.11 0.14 0.01 8.2 98.94 h2 70 68.13 14.19 4.31 1.16 0.67 1.30 1.88 1.24 0.11 0.07 0.01 5.6 98.67 h2 150 62.43 16.49 4.93 0.71 0.49 0.59 1.42 1.17 0.02 0.03 0.01 8.0 96.31 h2 250 57.65 18.59 5.15 0.97 0.61 0.64 1.60 1.00 0.03 0.02 0.01 9.2 95.46 g eologia c roatica 315gverić et al.: the influence of weathering and pedogenesis on the geochemical record of miocene marls and plio-quaternary sediments ... minerals in some samples. plq sections are more complicated as plq sediments were locally covered by loess which was subsequently altered. chaotic proluvial sedimentation during this period also resulted in substantial differences in plq sediment material, especially considering mineral content and granulometric properties. the samples show variation in texture; the dotrščina samples are silt loam throughout, while the oporovec samples vary from silty clay to silt loam and the horvatovac borehole plq sediment is silty clay with the overlying soil having silt and silt loam horizons. there is a lithic discontinuity present in the dotrščina and horvatovac sections. the samples do not contain carbonates; the chemical composition is dominated by si, al and fe (table 2), and the phh2o values range from 4.2 to 6.7 (gverić et al., 2023). the elemental composition for plq sections samples was determined at the institute of geology, jagiellonian university, kraków, poland, using spectro arcos (icp­oes) spectrometer (spectro analytical instruments gmbh, kleve, germany) with the radially (side­on) viewed torch configuration. the samples were digested in a mixture of spectrally clean and concentrated nitric, hydrochloric, and hydrofluoric acids in the presence of boric acid in the ethos­up milestone microwave oven (milestone srl, sorisole (bg), italy). certified reference material oreas 920 (oreas®, melbourne, australia) was processed and measured in the same way as the samples in the same analytical cycle to monitor the accuracy of the analyses. 3.3. provenance and selected weathering indicators to assert provenance, tio2/al2o3 and sm/nd ratios were related to the eu/eu* ratio in order to compare the geochemical signature of the samples to the known values for different types of rocks taken from condie (1993). the values taken are for the phanerozoic or average paleozoic and mesozoic protolith. the analysis of provenance based on trace and rare earth elements (rees) was undertaken on miocene marl samples and diagrams la­th­sc and th­sc­zr/10 proposed by bhatia & crook (1986) were used for this purpose. ree concentrations were normalized to chondrite values (mcdonough & sun, 1995) to detect any differentiation of the elements in earlier geological processes, and to upper continental crust values (rudnick & gao, 2014) to account for their subsequent distribution during weathering and pedogenesis. ratios of the major chemical elements (na/ti, ca/ti, al/ na, al/k, al/ti) as well as la/sm ratio were used to detect element (im)mobility and to make further comparisons between the parent material and the overlying soil, with respect to the weathering intensity and its impact on the mineral and chemical record. the extent of (chemical) weathering for profiles developed on miocene carbonate sediments was inferred from calculation of a mass transfer coefficient (τ) for the main elements (si, al, fe, mg, ca, na and k) with ti considered an immobile element (brimhall & dietrich, 1987; chadwick et al., 1990; yang et al., 2015). for plq sections, having a more complex development and exhibiting lithic discontinuity in two of the investigated localities, weathering indices listed in table 3 were used. given that the studied plq colluvial sediments incorporate geochemical signatures of past weathering cycles with various protoliths included, a range of different weathering indices was used and compared. the main motive was to observe the trends, not the absolute values, and also to evaluate the suitability of the indices used for proluvial material derived from multiple sources. weathering indices used were the chemical index of alteration (cia; nesbitt & young, 1982), as the most commonly employed quantitative measure of chemical alteration, and the plagioclase index of alteration (pia; fedo et al., 1995) which accounts for k immobilization due to clay mineral formation. we have also calculated the chemical index of weathering (ciw; harnois, 1988), which excludes k from the calculation due to its possible retention in some clay mineral phases, and chemical proxy of alteration (cpa; buggle et al., 2011), which omits both ca and k from the calculation and is found to be the most suitable for loess and paleosol samples. the aforementioned chemical indices, although initially mostly developed to measure geochemical weathering effects in silicate rocks, have so far been used for a wide variety of soil and sediment samples (e.g., wei et al., 2006; taboada et al., 2016; dinis et al., 2020; heidari et al., 2022). the fraction of poorly ordered fe and mn oxides was deter mined for the plq sections after dissolution of the samples in acid ammonium oxalate (method according to schwertmann, 1964). the samples were suspended in acid ammonium oxalate and the reaction proceeded in the dark. after filtration (also in the dark), fe and mn con cen­ trations (ammonium oxalate extractable iron and manganese) were measured from the filtrate using aas (analyst 700). 4. results and discussion 4.1. tectonic setting and material provenance relationships between eu/eu* and tio2/al2o3 as well as between eu/eu* and sm/nd show marl samples plotting near ucc and paas values, while the plq samples’ values are more scattered (fig. 2). provenance data for the miocene marl samples as well as for their derivatives imply their origin from a well­differentiated continental material that can be averaged to the shale geochemical signature. when assessing the provenance and tectonic setting for plq samples, a proluvial table 3. weathering indices used for the samples of plq sections (calculated on the basis of the molar proportions of the element oxides). index formula reference cia [al2o3 / (al2o3+k2o+cao+na2o)] x 100 nesbitt & young, 1982 pia [(al2o3-k2o )/(al2o3+cao+na2o-k2o)] x 100 fedo et al., 1995 ciw [al2o3/(al2o3 + cao +na2o)] x 100 harnois, 1988 cpa [al2o3/(al2o3 + na2o)] x 100 buggle et al., 2011 g eo lo gi a c ro at ic a 316 geologia croatica 77/3 nature of the sediments has to be taken into consideration; torrential streams eroded upstream rocks of various ages and origin, resulting in the accumulation of plq sediments in the foothills of medvednica mt (fig. 1). the tectonic setting for miocene sedimentary rocks and overlying soil samples was established using trace elements discriminatory plots proposed by bhatia & crook (1986). the results place the samples in the continental island arc field, thereby corresponding to the results of grizelj et al. (2017), obtained for miocene pelitic sediments of the area (fig. 3). this also corresponds with the definition of the pbs as a back­ arc basin (royden et al., 1983) and the postulated repeated extensions and inversion affecting the area since the early miocene (tomljenović & csontos, 2001; tomlje­ nović et al., 2008). the use of major elements in inferring provenance and tectonic setting (such as roser & korsch, 1986) has proven to give erroneous results. the issue with the parameters used in samples containing clay minerals could be the pre fe­ rential k+ retention in the interlayer space (bergaya et al., 2006), resulting in non­representative k2o/na2o ratio values. 4.2. ree distribution ree distribution (table 4) shows the primary enrichment of ree in the source material as evidenced by chondrite nor ma­ lization (figs. 4a,b). the enrichment of lree compared to chondrite values is particularly pronounced, with the enrich­ ment factor from 50 to up to several hundreds. all samples, except dot 120, show a negative eu anomaly. the general enrichment and trend is similar for both miocene and plq parent sediments as well as for their derivatives. the eu ano­ maly suggests the sediments were derived from already diffe­ ren tiated material. when rees are normalized to ucc (fig. 4c,d), all samples generally present ree abundances around those of nor ma li­ za tion standards. a flat distribution trend indicates no prefe­ rential leaching of particular rees during weathering or pedogenesis (see later discussion of the la/sm ratio throughout the samples). for all normalization cases, no significant dis­ figure 2. (a) eu/eu* and tio2/al2o3 binary plot, and (b) eu/eu* and sm/nd binary plot, showing the geochemical signature of the samples in relation to the reference values of some common rock types (data from condie, 1993). figure 3. samples from miocene marls profiles plotted on discrimination plots for tectonic settings according to bhatia & crook (1986). data on trace element composition used are available in the supplementary materials. g eologia c roatica 317gverić et al.: the influence of weathering and pedogenesis on the geochemical record of miocene marls and plio-quaternary sediments ... tinction between the parent material and soil/weathered ma­ terial is observed, supporting a presumption of overall inter­ mediate weathering intensity. miocene and plq profiles can be readily distinguished by the magnitude and the trend of ree distribution in all normalization cases. this could be partly attributed to the granulometric variations of the samples; miocene fine­grained samples contrast the sand­silt­clay features of the plq samples. additionally, these variations in ree distribution can also attest to different source material properties. 4.3. element mobility the mobility of chemical elements depends, among other factors, on the intensity of weathering processes. alkali and table 4. concentrations of ree (in ppm) of the studied samples. sample y la ce pr nd sm eu gd tb dy ho er tm yb lu eu/eu* (ch) (lree/ hree)ucc m io ce ne p ro fil es lzb 0-10 19.2 20.1 37.6 4.6 16.9 3.4 0.7 3.3 0.5 3.0 0.7 1.8 0.3 1.6 0.3 0.64 0.74 lzb 10-30 15.5 17.0 33.7 3.9 14.7 3.0 0.6 2.8 0.5 2.7 0.6 1.5 0.2 1.4 0.2 0.61 0.73 lzb 30-50 16.3 17.0 31.3 3.8 14.2 2.9 0.6 3.0 0.5 2.7 0.6 1.5 0.2 1.4 0.2 0.64 0.74 čuč 0-20 13.2 14.8 25.7 3.2 11.5 2.3 0.5 2.4 0.4 2.3 0.4 1.3 0.2 1.2 0.2 0.61 0.73 čuč 200 10.6 11.2 17.6 2.5 9.2 1.8 0.4 1.9 0.3 1.8 0.4 1.1 0.1 0.9 0.1 0.64 0.71 mtr 0-20 36.5 43.7 83.6 10.2 37.6 7.5 1.6 7.0 1.1 6.3 1.3 3.6 0.5 3.3 0.5 0.67 0.80 mtr 35-40 12.5 14.8 27.4 3.4 12.8 2.4 0.6 2.5 0.4 2.1 0.4 1.3 0.2 1.2 0.2 0.69 0.79 mtr 150 13.0 15.2 27.9 3.4 12.8 2.6 0.5 2.4 0.4 2.1 0.4 1.3 0.2 1.1 0.2 0.64 0.81 fur 0-20 29.3 39.0 72.8 8.7 32.1 6.3 1.3 5.7 0.9 5.0 1.0 2.9 0.4 2.7 0.4 0.65 0.86 fur 20-60 16.0 20.8 39.5 4.7 17.8 3.4 0.7 3.2 0.5 2.8 0.6 1.6 0.2 1.4 0.2 0.69 0.86 fur 70 16.6 21.6 39.6 4. 8 17.5 3. 5 0.7 3.3 0.5 2.9 0.5 1.6 0.2 1.5 0.2 0.66 0.86 jes 0-20 23.9 30.0 57.7 6.8 25.5 4.8 1.0 4.5 0.7 4.0 0.8 2.4 0.3 2.2 0.3 0.66 0.84 jes 20-40 24.4 31.4 61.5 7.2 27.0 5.1 1.1 4.7 0.7 4.1 0.8 2.4 0.4 2.2 0.3 0.69 0.85 jes 40-90 23.0 30.9 59.7 7.0 26.5 5.0 1.0 4.7 0.7 4.2 0.8 2.3 0.3 2.2 0.3 0.65 0.85 jes 220 26.2 34.0 65.4 7.9 29.4 5.7 1.2 5.2 0.8 4.7 0.9 2.7 0.4 2.5 0.4 0.66 0.84 pl q s ec tio ns dot 25 25.7 45.4 110.0 18.3 29.1 7.7 1.1 6.9 2.8 7.2 1.1 <5 <2 1.9 <2 0.44 1.21 dot 120 25.2 45.3 124.0 9.0 30.5 8.3 1.7 6.1 4.1 11.3 1.2 <5 <2 2.0 <2 0.73 0.87 dot 300 22.0 40.6 63.2 12.0 25.4 6.4 0.7 4.9 3.7 6.3 1.1 <5 <2 1.7 <2 0.39 0.82 opo 25 22.6 44.6 108.0 18.2 29.3 7.4 0.9 5.8 3.3 6.2 1.2 <5 <2 1.8 <2 0.42 1.11 opo 40 27.1 49.2 114.0 14.7 35.0 8.5 1.2 6.1 4.1 6.9 1.1 <5 <2 2.1 <2 0.49 1.00 opo 70 40.3 65.6 132.0 13.9 48.1 10.7 1.8 8.5 3.6 8.7 1.3 <5 <2 2.9 <2 0.56 1.15 h2 25 26.0 47.7 106.0 11.7 34.3 8.5 1.3 6.1 4.0 7.4 1.2 <5 <2 2.0 <2 0.55 0.96 h2 70 22.0 44.1 91.8 16.0 30.2 7.5 1.0 5.4 3.0 5.9 1.3 <5 <2 1.6 <2 0.47 1.11 h2 150 20.2 38.9 94.5 9.6 23.6 6.6 0.9 4.8 2.8 5.7 0.9 <5 <2 1.5 <2 0.47 1.03 h2 250 23.8 43.3 68.4 12.2 28.4 7.1 0.9 6.0 3.3 6.6 1.2 <5 <2 1.9 <2 0.43 0.93 figure 4. normalization plots for ree: (a) samples from the miocene marl profiles and (b) samples from the plq sections normalized to chondrite ( mcdonough & sun, 1995); (c) samples from the miocene marl profiles and (d) samples from the plq sections normalized to upper continental crust values (rudnick & gao, 2014). g eo lo gi a c ro at ic a 318 geologia croatica 77/3 alkaline earth elements are generally considered mobile and easily removed from the parent material during weathering (nesbitt et al., 1980; nesbitt & markovics, 1997), while elements such as al and ti tend to be conserved in weathered material and are considered immobile in the case of moderate chemical weathering, especially in slightly alka­ line environments (nesbitt et al., 1980; peuraniemi & pulkkinen, 1993; nesbitt & markovics, 1997). the strong positive correlation of the al and ti content in the mio­ cene marl profiles indicates a low mobility of the two elements and their enrichment in the detrital component of marls, which is also reflected in the overlying soil samples (fig. 5). the scatter of samples from the plq sections corre sponds to their multiple source origin. the sediment samples show a clear separation from the corresponding soil samples in the plq sections, although the scatter, which indicates a more chaotic origin, is also preserved in the overlying soil samples. elemental ratios sensitive to chemical weathering were compared between parent material and topsoil samples to discern the trends within profiles (fig. 6). since na and ca are figure 5. correlation of tio2 with al2o3 for samples of the miocene marl profiles (blue line) and the plq sections (orange line). figure 6. elemental ratios comparison between topsoil and the parent material/bedrock. the arrows indicate trends under increased weathering intensity. g eologia c roatica 319gverić et al.: the influence of weathering and pedogenesis on the geochemical record of miocene marls and plio-quaternary sediments ... easily removed during chemical weathering (nesbitt & young, 1982), their ratio to ti is decreased in more weathered samples. ti is expected to stay immobile under all circum­ stances apart from extreme chemical weathering conditions (nesbitt & markovics, 1997; sheldon & tabor, 2009), which is not assumed for these samples due to the presence of feldspars and expandable clay minerals (gverić et al., 2022, 2023). there is a similarity in the distribution of both ratios in the miocene marl samples, suggesting that topsoil is more depleted in the aforementioned elements than the parent material. however, in the plq samples the topsoil is depleted in ca, while the same is not true for na (fig. 6a,b). in the miocene profiles, the al/k ratio in the soil samples is generally higher than in the parent material, which is more pronounced in some of the studied profiles, whereas the trend is reversed in the plq sections (fig. 6d). al/k ratios tend to increase during chemical weathering of stronger intensity (wei et al., 2006), as k will then more easily be leached out instead of incorporated into clay minerals structure (nesbitt et al., 1980). this, albeit subtly, is evident in the marl profiles and soils developed on top of the genetically related parent material, suggesting an expected weathering and pedogenesis pattern. for plq sections, in which soil and parent material are not necessarily genetically related, the al/k ratio shows a geo­ chemical signature of higher weathering intensity, (or longer weathering exposure), in the plq sediment material than in the overlying soil samples. la/sm ratios, which can trace more intense chemical weathering occurrences (wei et al., 2006), indicate a similar conclusion, showing the greatest increase in plq sediments of dotrščina and horvatovac when compared to the respective topsoil samples (fig. 6f). substantial dif­ ferences shown in the element ratios between rock and soil samples in the plq sections also confirm the fact that this soil was developed on an unrelated parent material (most likely loess derivate), as previously postulated (gverić et al., 2023). differences in the absolute values of elemental ratios between different miocene marl profiles can also reflect the different source material for the siliciclastic component of the marls; material of local origin (inner dinarides) during the early miocene was gradually replaced with material from more distant source areas (the alps, carpathians) by the late miocene (grizelj et al., 2017). in the plq sections, the sediment is exclusively of local origin and was deposited in a shorter period of time from torrents, with a composition influ­ enced by local lithological variations, as well as the transport mechanism. 4.4. geochemical weathering signature and correspondence between geochemical and mineralogical proxies for profiles on miocene sedimentary rocks the clay mineralogy of marl samples indicates an inter mediate weathering intensity. clay minerals in the soil profiles developed on the miocene marls are largely inherited from the parent material with early stages of transformation visible in the occurrence of mixed­layered species detected in the uppermost soil horizons (gverić et al., 2022). transformations are, however, very subtle and impeded by the high ph caused by the presence of carbonates. changes in the major element composition in weathered material and soil samples developed on miocene carbonate­ rich sedimentary rocks (table 5), show the greatest variations in ca content, reflecting both carbonate dissolution in most profiles and secondary carbonate formation detected in the jesenovec profile (gverić et al., 2022). there is no notable accumulation of al and only a slight loss of alkali elements. loss of k observed in some soil samples reflects the progressive loss of illite layers in mixed­layered illite smectite towards the profile surface (gverić et al., 2022). 4.5. geochemical weathering signature and correspondence between geochemical and mineralogical proxies for the plq sediment and overlying soil most indices of chemical weathering show similar trends for all the plq sections (table 6). cia values are in the range of table 5. variations of major elements relative to parent material composition (τ mass coefficient) (brimhall & dietrich, 1987). τsi τal τfe τmg τca τna τk lzb 0-10 0.14 0.05 0.19 -0.13 -0.20 -0.02 -0.02 lzb 10-30 0.03 0.04 0.18 -0.11 -0.18 -0.05 0.03 čuč 0-20 0.03 -0.01 0.14 -0.20 -0.50 -0.04 -0.14 mtr 0-20 -0.22 -0.13 -0.04 -0.78 -0.96 -0.16 -0.34 mtr 35-40 -0.04 0.02 0.08 -0.19 0.06 0.04 0.00 fur 0-20 -0.15 -0.12 -0.10 -0.54 -0.84 -0.25 -0.17 fur 20-60 -0.03 0.04 0.01 -0.15 0.11 -0.15 0.09 jes 0-20 -0.04 -0.02 0.08 -0.01 1.07 -0.10 -0.03 jes 20-40 -0.03 0.00 0.02 -0.06 0.82 -0.07 -0.05 jes 40-90 0.00 0.06 0.21 -0.08 1.15 0.00 0.02 table 6. weathering indices calculated for plq sections samples. cia ciw pia cpa dot 25 80 88 87 91 dot 120 81 90 89 93 dot 300 79 84 82 91 opo 25 82 92 91 94 opo 40 85 94 93 96 opo 70 85 94 93 97 h2 25 80 89 88 93 h2 70 79 88 86 92 h2 150 87 94 93 97 h2 250 87 94 93 97 g eo lo gi a c ro at ic a 320 geologia croatica 77/3 geochemical indices and observed feo/fet ratios. the only exception, dotrščina, shows the most advanced pedogenesis and the development of a stagnosol, i.e. a pseudogley soil (gverić et al., 2023). even though the nature and origin of the plq sediments is problematic in the context of geochemically derived conclusions, all of the weathering indices used show the same trends, and correspond well with previously obtained mineralogical and pedological information. 5. conclusions the results of this study show that, in general, there is a good correlation between the geochemical and mineralogical weathering signatures in the parent materials, weathered materials and soil samples, which were analyzed in the foothill area of medvednica mt. the very subtle effects of weathering and pedogenesis in the miocene profiles studied, already suggested by the mineralogical data, are now confirmed by the absence of any appreciable enrichment of al and only a slight loss of alkali and alkaline earth elements, in agreement with the previously postulated changes in mineralogy. the geo che­ mi cal weathering indices in the investigated plq sections also agree with the previously determined mineralogical contents and show higher values in the samples that also contain more low-charge expandable clay minerals as well as fe and al oxides. while the geochemical signatures of the parent material are largely preserved in the soil profiles developed on the miocene sediments, they show marked heterogeneity both between the plq sediments and the overlying soil samples. within soils developed on miocene sediments, we therefore observe the consequences of pedogenesis with distinct geochemical and mineralogical (shown in previous study) changes on one and the same parent material. the observed discrepancy between the soils/weathered materials and the plq sediments is the result of the heterogeneity of the parent materials, (as a con­ sequence of proluvial sedimentation of these deposits) and their weathering status (pre-weathered sediments), prior to their final deposition as proluvial sediment. likewise, the geochemical composition indicates that the miocene marl samples are derived from a well-differentiated continental material, while the provenance signature of the plq sediments corresponds to their diverse multi­source origin. acknowledgement the authors would like to thank the editor and two anonymous reviewers for their thorough and helpful comments which substantially improved the manuscript. the results presented in this paper are a part of the phd dissertation of the first author. this work was partly financed by the university of zagreb [grants no. 20286304 and no. 20286480]. the authors are grateful to dr. dorota salata from the institute of geological sciences of the jagiellonian university in kraków for the chemical composition analysis of the plq samples, and to dr. michaela hruškova hasan from the department of mine ra logy, petrology and mineral resources of the faculty of mining, geology and petroleum engineering, university of zagreb for conducting the aas analysis. 79 to 87, corresponding to intermediate to intense degrees of weathering (nesbitt & young, 1982; fedo et al., 1995). ciw and pia show similar trends and range from 84 to 94 and 82 to 93, respectively. both indices show higher absolute values than the cia, which is expected due to the omission of k2o (ciw) or the correction for k2o (pia) in the calculations. cpa shows values of 91 to 97. there is a general discrepancy between the plq sediment samples and the overlying soil samples of the oporovec and horvatovac localities. the sediment samples consistently have indices corresponding to more intense weathering than the overlying soil samples. this is in line with the theory of soil formation in different weathering conditions and from more recent sediments, such as subsequently deposited loess material. ammonium oxalate extractable fe and mn were measured for the plq samples to determine the ratio of poorly crystallized fe and mn to total fe and mn (table 7). as a consequence of the initial stage of soil development at the sites studied, there is a higher ratio of poorly crystallized fe (feo) to total fe (fet) in the soil than in the parent material, as shown in table 5. this is not evident for mn, since mn oxyhydroxides are very readily remobilized in soil. geochemistry of the plq sections confirms the fact postulated in the previous study (gverić et al., 2023), that the soil horizons most likely developed from subsequently deposited material. the clay minerals assemblage in the plq samples generally corresponds to a higher intensity and degree of weathering during the earlier plq sediment deposition, observed by the presence of low-charge expandable minerals (smectite) and fe/al (oxy)hydroxides (gverić et al., 2023). however, the presence of feldspar (and expandable clay minerals) in all of the plq sediment samples suggests either that those possible intense weathering periods were not longlasting or that the material originates from multiple sources that have undergone various degrees of weathering. subsequent weathered material and overlying soil samples in which hydroxy-interlayered minerals were detected, as well as the (locally dominant) presence of high-charge expandable minerals (vermiculite), correspond to a lower intensity and degree of weathering, also evidenced by the calculated table 7. ammonium oxalate extractable fe and mn content (in ppm) and their fraction in total fe and mn of the plq sections. total fe and mn values are recalculated from table 2. sample feo mno feo/ fet mno/mnt dot 25 92 13 0.0034 0.0127 dot 120 126 66 0.0030 0.0180 dot 300* 59 8 0.0013 0.0682 opo 25 99 3 0.0037 0.0069 opo 40 88 3 0.0026 0.0074 opo 70* 77 7 0.0021 0.0109 h2 25 81 14 0.0021 0.0126 h2 70 77 4 0.0025 0.0082 h2 150* 16 b.d.l. 0.0005 h2 250* 22 2 0.0006 0.0183 * marks plq sediment samples b.d.l. = below detection limit g eologia c roatica 321gverić et al.: the influence of weathering and pedogenesis on the geochemical record of miocene marls and plio-quaternary sediments ... references bakrač, k. & koch, g. (1999): a palynological contribution to the qua­ ternary deposits in the wider area of zagreb (croatia).– acta palaeobot. suppl. 2, 467–469. bakrač, k., koch, g. & sremac, j. (2012): middle and late miocene palynological biozonation of the south­western part of central parate­ thys (croatia).– geol. croat., 65, 207–222. doi: 10.4154/gc.2012.12 banwart, s., menon, m., bernasconi, s.m., bloem, j., blum, w.e.h., souza, d.m., davidsdotir, b., duffy, c., lair, g.j., kram, p., lamacova, a., lundin, l., nikolaidis, n.p., no­ vak, m., panagos, p., ragnarsdottir, k.v., reynolds, b., robinson, d., rousseva, s., de ruiter, p., van gaans, p., weng, l., white, t. & zhang, b. (2012): soil processes and fun­ ctions across an international network of critical zone observatories: introduction to experimental methods and initial results.– comptes ren­ dus.– geosci., 344, 758–772. doi: 10.1016/j.crte.2012.10.007 basch, o. (1981): osnovna geološka karta sfrj 1:100 000. list ivanić grad l33­81 [basic geological map of sfry 1:100 000, ivanić grad sheet ­ in croatian] ­ geološki zavod, zagreb, savezni geološki zavod, beograd. bergaya, f., lagaly, g. & vayer, m. (2006): cation and anion exc­ hange.– in: bergaya, f., theng, b.k.g. & lagaly, g. (eds.): han­ dbook of clay science: developments in clay science, vol. 1. elsevier, 979–1001. doi: 10.1016/s1572­4352(05)01036­6 bhatia, m.r. & crook, k.a.w. (1986): trace element characteristics of graywackes and tectonic setting discrimination of sedimentary basins.– contrib. to mineral. petrol., 92, 181–193. doi: 10.1007/bf00375292 błażejowski, b., pszczółkowski, a., grabowski, j., wier­ zbowski, h., deconinck, j.­f., olempska, e., teodorski, a. & nawrocki, j. (2023): integrated stratigraphy and clay minera­ logy of the owadów–brzezinki section (lower–upper tithonian tran­ sition, central poland): implications for correlations between the boreal and the tethyan domains and palaeoclimate.– j. geol. soc. london, 180. doi: 10.1144/jgs2022­073 brimhall, g.h. & dietrich, w.e. (1987): constitutive mass balance relations between chemical composition, volume, density, porosity, and strain in metasomatic hydrochemical systems: results on weathering and pedogenesis.– geochim. cosmochim. acta, 51, 567–587. doi: 10.1016/0016­7037(87)90070­6 buggle, b., glaser, b., hambach, u., gerasimenko, n. & mar­ ković, s. (2011): an evaluation of geochemical weathering indices in loess­paleosol studies.– quat. int., 240, 12–21. doi: 10.1016/j.qua­ int.2010.07.019 chadwick, o.a., brimhall, g.h. & hendricks, d.m. (1990): from a black to a gray box – a mass balance interpretation of pedogenesis.– geomorphology, 3/3, 369­390. doi: 10.1016/0169­555x(90)90012­f condie, k.c. (1993): chemical composition and evolution of the upper con­ tinental crust: contrasting results from surface samples and shales.– chem. geol., 104, 1–37. doi: 10.1016/0009­2541(93)90140­e corentin, p., pucéat, e., pellenard, p., guiraud, m., blondet, j., bayon, g. & adatte, t. (2023): late cretaceous evolution of che­ mical weathering at the northeastern south american margin inferred from mineralogy and hf­nd isotopes.– mar. geol., 455, 106968. doi: 10.1016/j.margeo.2022.106968 croatian geological survey (2009): geological map of the repu­ blic of croatia 1:300000.– croatian geological survey, department of geology, zagreb. dinis, p.a., garzanti, e., hahn, a., vermeesch, p. & cabral­ pinto, m. (2020): weathering indices as climate proxies. a step forward based on congo and sw african river muds.– earth­science rev., 201. doi: 10.1016/j.earscirev.2019.103039 fedo, c.m., nesbitt, w.h. & young, g.m. (1995): unraveling the effe­ cts of potassium metasomatism in sedimentary rocks and paleosols, wi­ th implications for paleoweathering conditions and provenance.– geo­ logy, 23, 921. doi: 10.1130/0091­7613(1995)023<0921:uteopm>2.3.co;2 frings, p.j. & buss, h.l. (2019): central role of weathering in the geo­ sciences planetary weathering thermostats plants, ecosystems, and weathering sculpting earth’s surface combating climate change: en­ hanced weathering palaeoweathering weathering across the earth sciences.– elem. an int. mag. mineral. geochemistry, petrol, 15, 229– 234. doi: 10.2138/gselements.15.4.229 galović, l. & peh, z. (2014): eolian contribution to geochemical and mi­ neralogical characteristics of some soil types in medvednica mountain, croatia.– catena, 117, 145–156. doi: 10.1016/j.catena.2013.12.016 godoy, l.h., sardinha, d. de s. & moreno, m.m.t. (2017): major and trace elements redistribution in weathered claystones from the corumbataí formation, paraná sedimentary basin, são paulo, brazil.– brazilian j. geol., 47, 615–632. doi: 10.1590/2317­4889201720170086 grizelj, a., peh, z., tibljaš, d., kovačić, m. & kurečić, t. (2017): mineralogical and geochemical characteristics of miocene pelitic sedi­ mentary rocks from the south­western part of the pannonian basin system (croatia): implications for provenance studies.– geosci. front., 8, 65–80. doi: 10.1016/j.gsf.2015.11.009 gverić, z., rubinić, v., kampić, š., vrbanec, p., paradžik, a. & tomašić, n. (2022): clay mineralogy of soils developed from mi­ ocene marls of medvednica mt., nw croatia: origin and transformation in temperate climate.– catena, 216, 106439. doi: 10.1016/j.cate­ na.2022.106439 gverić, z., tomašić, n., kisiel, m., maj­szeliga, k., skiba, m. & rubinić, v. (2023): the effect of weathering on clay mineralogy of plio­quaternary sediments and the overlying material on se slopes of medvednica mt., croatia.– environ. earth sci., 82, 1–15. doi: 10.1007/ s12665­023­11042­7 hall, k., thorn, c. & sumner, p. (2012): on the persistence of “weat­ hering”.– geomorphology, 149–150, 1–10. doi: 10.1016/j.geo­ morph.2011.12.024 harnois, l. (1988): the ciw index: a new chemical index of weathering.– sediment. geol., 55, 319–322. doi: 10.1016/0037­0738(88)90137­6 harzhauser, m., latal, c. & piller, w.e. (2007): the stable isotope archive of lake pannon as a mirror of late miocene climate change.– palaeogeogr. palaeoclimatol. palaeoecol., 249, 335–350. doi: 10.1016/j. palaeo.2007.02.006 harzhauser, m., peresson, m., benold, c., mandic, o., ćorić, s. & de lange, g.j. (2023): environmental shifts in and around lake pannon during the tortonian thermal maximum based on a multi­proxy record from the vienna basin (austria, late miocene, tortonian).– pa­ laeogeogr. palaeoclimatol. palaeoecol., 610. doi: 10.1016/j.pala­ eo.2022.111332 heidari, a., osat, m. & konyushkova, m. (2022): geochemical in­ dices as efficient tools for assessing the soil weathering status in relation to soil taxonomic classes.– catena, 208, 105716. doi: 10.1016/j.cate­ na.2021.105716 jiménez­moreno, g., rodríguez­tovar, f.j., pardo­igúzqui­ za, e., fauquette, s., suc, j.p. & müller, p. (2005): high­reso­ lution palynological analysis in late early­middle miocene core from the pannonian basin, hungary: climatic changes, astronomical forcing and eustatic fluctuations in the central paratethys.– palaeogeogr. palaeocli­ matol. palaeoecol., 216, 73–97. doi: 10.1016/j.palaeo.2004.10.007 kovačić, m., horvat, m., pikija, m. & slovenec, d. (2011): com­ position and provenance of neogene sedimentary rocks of dilj gora mt. (south pannonian basin, croatia).– geol. croat., 64, 121–132. doi: 10.4154/gc.2011.10 kurečić, t., kovačić, m. & grizelj, a. (2021): mineral assemblage and provenance of the pliocene viviparus beds from the area of vuko­ meričke gorice, central croatia.– geol. croat., 74, 253–271. doi: 10.4154/ gc.2021.16 lozić, s. (2001): multivariate approach to relief classification and typo­ logy – the example of north­western croatia.– acta geogr. croat., 35, 19–42. marković, f., kuiper, k., ćorić, s., hajek­tadesse, v., herni­ tz kučenjak, m., bakrač, k., pezelj, đ. & kovačić, m. (2021): middle miocene marine flooding: new40 ar/39ar age constra­ g eo lo gi a c ro at ic a 322 geologia croatica 77/3 ints with integrated biostratigraphy on tuffs from the north croatian ba­ sin.– geol. croat., 74, 237–252. doi: 10.4154/gc.2021.18 mcdonough, w.f. & sun, s. (1995): the composition of the earth.– chem. geol., 120, 223–253. doi: 10.1016/0009­2541(94)00140­4 mihalić arbanas, s., krkač, m. & bernat, s. (2016): application of advanced technologies in landslide research in the area of the city of zagreb (croatia, europe).– geol. croat., 69/2, 231–243. doi: 10.4154/ gc.2016.18 nesbitt, h.w. & markovics, g. (1997): weathering of granodioritic crust, long­term storage of elements in weathering profiles, and petro­ genesis of siliciclastic sediments.– geochim. cosmochim. acta, 61, 1653–1670. doi: 10.1016/s0016­7037(97)00031­8 nesbitt, h.w. & young, g.m. (1982): early proterozoic climates and pla­ te motions inferred from major element chemistry of lutites.– nature, 299, 715–717. doi: 10.1038/299715a0 nesbitt, h.w., markovics, g. & price, r.c. (1980): chemical proce­ sses affecting alkalis and alkaline earths during continental weathering.– geochim. cosmochim. acta, 44, 1659–1666. doi: 10.1016/0016­ 7037(80)90218­5 pavelić, d. & kovačić, m. (2018): sedimentology and stratigraphy of the neogene rift­type north croatian basin (pannonian basin system, cro­ atia): a review.– mar. pet. geol., 91, 455–469. doi: 10.1016/j.marpet­ geo.2018.01.026 pavelić, d., kovačić, m., banak, a., jiménez­moreno, g., mar­ ković, f., pikelj, k., vranjković, a., premužak, l., ti­ bljaš, d. & belak, m. (2016): early miocene european loess: a new record of aridity in southern europe.– bull. geol. soc. am., 128, 110– 121. doi: 10.1130/b31280.1 perković, i., pernar, n., bakšić, d., glamočlija, n. & roje, v. (2017): the effect of parent material on physical and mineral soil proper­ ties on medvednica nature park.– šumar. list, 141, 237–245. doi: 10.31298/sl.141.5­6.2 peuraniemi, v. & pulkkinen, p. (1993): preglacial weathering crust in ostrobothnia, western finland, with special reference to the rauda­ skylä occurrence.– chem. geol., 107, 313–316. doi: 10.1016/0009­ 2541(93)90198­r prista, g.a., agostinho, r.j. & cachão, m.a. (2015): observing the past to better understand the future: a synthesis of the neogene climate in europe and its perspectives on present climate change.– open geo­ sci., 65–83. doi: 10.1515/geo­2015­0007 roser, b.p. & korsch, r.j. (1986): determination of tectonic setting of sandstonemudstone suites using sio2 content and k2o/na2o ratio.– j. geol., 94, 635–650. doi: 10.1086/629071 royden, l., horváth, f., nagymarosy, a. & stegena, l. (1983): evolution of the pannonian basin system 2. subsidence and thermal history.– tectonics, 2, 91–137. doi: 10.1029/tc002i001p00091 rubinić, v., galović, l., lazarević, b., husnjak, s. & durn, g. (2018): pseudogleyed loess derivates – the most common soil parent materials in the pannonian region of croatia.– quat. int., 494, 248–262. doi: 10.1016/j.quaint.2017.06.044 rudnick, r.l. & gao, s. (2014): composition of the continental crust.– in: holland, h.d. & turekian, k.k. (eds.): treatise on geoche­ mistry. elsevier, 1–51. doi: 10.1016/b978­0­08­095975­7.00301­6 schwertmann, u. (1964): differenzierung der eisenoxide des bodens durch extraktion mit ammoniumoxalat­lösung.– zeitschrift für pflan­ zenernährung, düngung, bodenkd., 105, 194–202. doi: 10.1002/ jpln.3591050303 sheldon, n.d. & tabor, n.j. (2009): quantitative paleoenvironmental and paleoclimatic reconstruction using paleosols.– earth­science rev., 95, 1–52. doi: 10.1016/j.earscirev.2009.03.004 šikić, k., basch, o. & šimunić, a. (1978): osnovna geološka karta sfrj 1:100.000 ­ list zagreb l33­80 [basic geological map of sfry 1:100000, sheet zagreb l33-80 – in croatian].– geological department of serbia, belgrade. šikić, k. (1995): geološki vodič medvednice [geological guide of medvednica – in croatian].– institut za geološka istraživanja, zagreb, 199 p. szabó, p., kovács, j., kocsis, l., vennemann, t., domingo, l., újvári, g., halmai, á., pirkhoffer, e. & codrea, v. (2022): pliocene ­ early pleistocene continental climate and vegetation in euro­ pe based on stable isotope compositions of mammal tooth enamel.– qu­ at. sci. rev., 288, 107572. doi: 10.1016/j.quascirev.2022.107572 taboada, t., rodríguez­lado, l., ferro­vázquez, c., stoops, g. & martínez cortizas, a. (2016): chemical weathering in the volcanic soils of isla santa cruz (galápagos islands, ecuador).– geode­ rma, 261, 160–168. doi: 10.1016/j.geoderma.2015.07.019 tomljenović, b. (2002): strukturne značajke medvednice i samoborskog gorja [structural features of medvednica and samobor mts – in croa­ tian].– unpublished phd thesis, university of zagreb, 208 p. tomljenović, b. & csontos, l. (2001): neogene­quaternary structures in the border zone between alps, dinarides and pannonian basin (hr­ vatsko zagorje and karlovac basins, croatia).– int. j. earth sci., 90, 560–578. doi: 10.1007/s005310000176 tomljenović, b., csontos, l., márton, e. & márton, p. (2008): tectonic evolution of the northwestern internal dinarides as constrained by structures and rotation of medvednica mountains, north croatia.– geol. soc. spec. publ., 298, 145–167. doi: 10.1144/sp298.8 van gelder, i.e., matenco, l., willingshofer, e., tomljeno­ vić, b., andriesen, p.a.m., ducea, m.n., beniest, a. & gru­ ić, a. (2015): the tectonic evolution of a critical segment of the dinari­ des­alps connection: kinematic and geochronological inferences from the medvednica mountains, ne croatia.– tectonics, 34, 1952–1978. doi: 10.1002/2015tc003937 wei, g., li, x.h., liu, y., shao, l. & liang, x. (2006): geochemical re­ cord of chemical weathering and monsoon climate change since the ear­ ly miocene in the south china sea.– paleoceanography, 21, 1–11. doi: 10.1029/2006pa001300 yang, j., cawood, p.a., du, y., li, w. & yan, j. (2016): reconstructing early permian tropical climates from chemical weathering indices.– ge­ ol. soc. am. bull., 128/5­6, 739–751. doi: 10.1130/b31371.1 zaninović, k., gajić­čapka, m., perčec tadić, m., vučetić, m., milković, j., bajić, a, cindrić, k., cvitan, l., katušin, z., kaučić, d., likso, t., lončar, e., lončar, ž., mihajlović, d., pandžić, k., patarčić, m., srnec, l. & vučetić, v. (2008): klimatski atlas hrvatske / climate atlas of croatia 1961­1990., 1971­ 2000.– meteorological and hydrological service of croatia, zagreb. zollinger, b., alewell, c., kneisel, c., brandová, d., petri­ llo, m., plötze, m., christl, m. & egli, m. (2017): soil forma­ tion and weathering in a permafrost environment of the swiss alps: a multi­parameter and non­steady­state approach.– earth surf. process.– landforms, 42, 814–835. doi: 10.1002/esp.4040 g eologia c roatica 323gverić et al.: the influence of weathering and pedogenesis on the geochemical record of miocene marls and plio-quaternary sediments ... supplement 1. concentrations of trace elements (in ppm) of the samples from profiles on marls. lzb 0-10 lzb 10-30 lzb 30-50 čuč 0-20 čuč 200 mtr 0-20 mtr 35-40 mtr 150 fur 0-20 fur 20-60 fur 70 jes 0-20 jes 20-40 jes 40-90 jes 220 ba 222 228 223 275 210 389 188 179 408 276 279 384 412 402 605 ni 199 270 148 45 35 65 33 31 70 44 42 51 55 62 61 sc 8 9 8 5 4 16 6 6 14 9 8 12 12 13 14 co 17.6 27.5 11.6 7.1 6.6 18.7 9.4 8.0 16.8 11.1 12.2 14.1 15.3 15.2 15.4 cs 13.5 14.6 12.6 3.2 2.7 7.9 3.4 3.5 8.5 5.1 5.1 6.7 7.2 7.6 8.3 ga 9.6 9.6 8.0 5.3 3.7 19.9 6.3 6.1 18.5 9.7 9.9 15.7 16.7 16.9 19.2 hf 2.3 1.9 1.8 1.6 1.5 6.0 1.3 1.3 4.4 1.5 1.8 3.7 4.2 2.9 3.9 nb 7.5 7.0 6.3 4.9 3.7 15.6 4.5 4.6 13.7 6.4 6.8 11.7 12.8 11.9 14.1 rb 61.7 70.2 60.7 49.1 35.9 104.9 42.1 45.1 118.7 68.2 65.7 109.4 114.5 116.3 134.3 sn 2 2 2 2 <1 3 1 1 3 2 2 3 3 3 4 sr 459.4 507.8 608.2 1214.2 2021.1 113.9 353.0 361.2 124.8 305.4 317.3 172.2 180.1 187.9 175.8 ta 0.5 0.5 0.4 0.4 0.3 1.1 0.4 0.3 0.9 0.5 0.4 0.8 0.8 0.8 0.8 th 6.5 7.4 5.4 4.3 3.4 13.0 5.1 5.3 12.4 7.4 7.2 10.5 11.1 11.4 12.1 u 2.1 1.8 1.6 2.2 2.6 2.5 1.5 2.2 2.1 2.1 1.4 2.2 2.2 2.0 3.0 v 62 64 62 46 38 127 53 51 116 67 64 95 107 105 120 w 1.4 1.6 1.9 0.9 1.1 2.1 0.7 0.9 2.2 1.4 1.1 1.9 2.0 2.1 2.2 zr 84.1 68.4 64.9 64.1 58.3 234.8 47.7 52.5 163.1 54.9 65.7 140.7 147.8 111.7 151.8 www.geologia-croatica.hr abstract comparative studies on hydrothermal alteration of submarine peperitic basalt occurrences related to the triassic early rifting of the neotethys were carried out in various parts of the dinarides and hellenides. the study areas included the displaced fragments of the dinarides in the darnó unit, ne hungary, the kalnik mts. in croatia and the vares-šmreka area in bosnia and herzegovina. in the hellenides, similar environments were studied in the stragopetra mts., greece. jurassic pillow basalts formed in a back-arc-basin of the neotethys were also studied in the szarvaskő unit, ne hungary, which also represents a displaced unit of dinaridic origin. within the submarine basaltic lava flows, six volcanic facies were distinguished. the hydrothermal alteration was characterised according to those facies. the first process was the albitisation of the rock-forming plagioclase at ~300°c in all localities. during the higher temperature stage of the subsequent cooling, chloritisation in the ground mass is typical for all types of basalts, however chlorite and rarely quartz formed in the fractures and amygdales of the triassic basalts, while chlorite, quartz and prehnite precipitated in the fractures of the jurassic rocks. at lower temperatures of this cooling-related process, calcite is a common mineral filling up the larger amygdales, jig-saw type fractures and other open spaces, but some epidote, pumpellyite, prehnite and laumontite also occur in the triassic basalts. the late stage alteration (occurring at the lowest temperature) is characterised by argillitisation at every locality. the observed hydrothermal alteration patterns also show slight differences according to the volcanic facies as a function of the distal/proximal setting in relation to the eruptive centres and the presence/absence of water-saturated and unconsolidated carbonate or siliciclastic sediments at the time of the emplacement of lava flows. the study revealed that the most important factors influencing mineralogy and zoning of hydrothermal alteration in these short lived local hydrothermal systems are the rapid cooling of the hydrothermal fluid, the dominance of the poorly evolved seawater as the source of hydrothermal fluid and the local, i.e. effective water/rock ratio, determined by the degree of fracturing in the rock. the mineralogical-textural peculiarities of the highly localised hydrothermal fluid/rock interaction in the studied submarine seamount type volcanoes are clearly different from the products of the large-scale hydrothermal processes occurring at mid-oceanic ridges. recognition of these differences is important in the evaluation of ore potential in the neotethyan realm or other areas with occurrences of submarine basaltic units. keywords: submarine basaltic volcanism, submarine hydrothermal processes, mineralogy and geochemistry of submarine fluid/ rock interaction, fluid inclusions, chlorite thermometry article history: received november 09, 2015 revised and accepted january 04, 2016 avaliable online february 29, 2016 1. introduction correlation and comparison of the triassic and jurassic submarine basaltic units in the darnó and szarvaskő units northeastern hungary, and similar occurrences in the dinarides and hellenides have been in the focus of several studies during past decades (see e.g. buda & kiss, 1980; balla et al., 1980; kubovics 1984; balla, 1987; downes et al., 1990; dosztály & józsa, 1992; harangi et al., 1996; józsa, 1999; haas & kovács, 2001; schmid et al., 2008; robertson et al., 2009 and the references cited therein). the results of the most recent investigations suggest that the formation of the triassic basaltic units found in ne hungary and in the dinarides and hellenides can be related to the advanced stage of rifting of the neotethys, while the jurassic basalts occurring in the same mélange in ne hungary have accumulated in a back-arc-basin or a marginal basin (harangi et al., 1996, aigner-torres & koller, 1999, kiss et al., 2008, 2010, 2012, kovács et al., 2008, 2010, haas et al., 2011). these basaltic units of different ages were emplaced into unconsolidated sediments (triassic – lime-mud, jurassic – fine grained siliciclastics) as discussed in detail in kiss et al. (2010, 2011, 2012). doi:10.4154/gc.2016.0439-64 17 figs. 7 tabs. hydrothermal processes related to some triassic and jurassic submarine basaltic complexes in northeastern hungary, the dinarides and hellenides gabriella b. kiss1,*, ferenc molnár1,2 and ladislav a. palinkaš3 1eötvös loránd university, faculty of science, department of mineralogy, pázmány p. stny 1/c, 1117 budapest, hungary (*corresponding author: g. b. kiss e-mail: gabriella.b.kiss@ttk.elte.hu, telephone number: +36-1-372-2500 ext. 8333) 2present address: geological survey of finland, po. box 96, fi-02151 espoo, finland 3university of zagreb, faculty of science, institute of mineralogy and petrology, horvatovac 95, 10000 zagreb, croatia vol. 69/1 40 comparison of the characteristics of submarine hydrothermal activities which affected these basaltic suites provides an additional tool to the correlation among the triassic localities. comparison of their overall characteristics to the jurassic system offers an opportunity to investigate the effect of the geotectonic setting on the peculiarities of submarine hydrothermal processes. this aids recognition of the timeand environmentindependent common characteristics of these hydrothermal systems. submarine volcanism related hydrothermal systems at the oceanic ridges are quite well known and documented, especially because of the formation of economically important volcanogenic massive sulfide ore deposits (see e.g. foustoukos & seyfried, 2007, pirajno, 2009 and the references therein). as a contrary, submarine volcanism-related hydrothermal processes have scarcely been studied in other geodynamic settings, e.g. advanced stage of rifting. distinguishing between the features of submarine hydrothermal alteration processes in the structurally-texturally similar basaltic rocks formed in different geotectonic settings is of obvious importance in mineral exploration. here, we present the mineralogical-textural-geochemical characteristics and the temporal and spatial evolution of the fluid/rock interaction in these submarine basaltic rocks. 2. regional setting the darnó unit the darnó unit (fig. 1.) is part of the bükk unit, located within the pelso unit of the alcapa block (alpine, carpathian, pannonian, csontos, 1995, schmid et al. (2008). it comprises an area of ca. 7km2 in ne hungary (centred on ~ n 47.936810, e 20.163246), in the vicinity of the city of eger. according to the latest tectonic models, the darnó unit forms the uppermost nappe in the complex structure of the bükk unit (which consists of four stacked nappes) (csontos, 1995, csontos, 1999, haas & kovács, 2001, kovács et al., 2008). the darnó unit consists of predominantly triassic and subordinately jurassic submarine basaltic suites and associated triassic and jurassic sedimentary rocks. the magmatic suites are pillow basalt sequences, however, in the triassic rocks, limey peperitic facies (i.e. unconsolidated sediment-lava mixing at the time of rock formation, skilling et al., 2002) also commonly occur (kiss et al., 2008, 2010, 2012, kovács et al., 2010). recent geochemical and volcanological studies of these triassic magmatic rocks suggest their emplacement occurred in an advanced rift-related tectonic setting. the whole figure 1. geological maps of the studied areas. a, structural sketch map of the circum-pannonian region and the balkan peninsula. b, geological sketch map of the darnó and szarvaskő units. c, geological sketch map of the area of vareš. d, geological sketch map of the area of hruškovec. e, geological sketch map of the avdella mélange. the studied localities are marked on each map. kiss et al.: hydrothermal processes related to some triassic and jurassic submarine basaltic complexes in northeastern hungary... 41 unit is interpreted as an accretionary mélange complex (balla et al., 1980, buda & kiss, 1980, dimitrijević et al., 2003, kovács et al., 2008, 2010, kiss et al., 2008, 2010, 2012). signs of alpine low grade metamorphism were observed nearby in the bükk mts. (see árkai, 2001 and references therein) and its effects on the darnó unit were documented by molnár et al. (2015). the szarvaskő unit the szarvaskő unit (fig. 1.) is also part of the bükk unit, within the alcapa block. it forms a nappe below the uppermost darnó unit, with outcrops mostly confined to a synform structure in the vicinity of the village of szarvaskő (n 47.988742, e 20.332144) (csontos, 1995, dosztály et al., 1998). the szarvaskő unit consists of an incomplete jurassic ophiolitic sequence intercalated with some deep water siliciclastic sediments. besides the well developed pillow basalt series with local siliciclastic peperite (kiss et al., 2011), gabbro and related plagiogranite, wehrlite, piroxenite and hornblendite also occur. however, other ultramafic rocks of true ophiolitic sequences are missing (szentpétery, 1953, balla, 1984, dosztály et al., 1998, pelikán ed. 2005). the k-ar age of the magmatic rocks is 165 +/5 ma and 166 +/8 ma according to árváné sós et al. (1987). balogh & pécskay (2001) obtained an ar-ar plateau age of 162.9 +/0.9 ma for contact-metasomatic k-mica occurring along the intrusive contact of a gabbro intrusion and host sediments. kohút & kiss (2013) reported 170 +/9 ma based on chemical emp dating of monazite of the plagiogranite associated with the gabbroic intrusion. current views suggest that formation of the incomplete ophiolitic sequence at szarvaskő is related to the opening of a back-arc-basin or a marginal basin (aigner-torres & koller, 1999, csontos, 2000, haas et al., 2011). its differentiation from characteristic midoceanic ridge related rocks was also proven by kiss et al. (2011). árkai (1983), árkai et al. (1995), sadek ghabrial et al. (1996), árkai (2001), péntek et al. (2006) and kiss et al. (2012) have also shown the occurrence of a very low and low grade alpine regional metamorphism related alteration mineral assemblage of cretaceous age. localities in the dinarides the kalnik mts. (fig. 1.) comprise two main tectonostratigraphic units in the northern part of croatia (centred on ~ n 46.150374, e 16.442340), in the zagorje-mid-transdanubian zone (zmtz) of the nw dinarides. one unit is the strongly tectonised ophiolitic mélange, the other being the late cretaceous-palaeogene flysch. the mélange mostly exhibits features characteristic of the dinarides, and is therefore interpreted as the most northwestern occurrence of the dinaridic ophiolite zone (pamić & tomljenović, 1998). the area of vareš (n 44.161424, e 18.326386) (fig. 1.) is located in bosnia and herzegovina, in the central dinarides. according to trubelja et al. (2004) the borovica-vareščeljanovići-kalinovik zone is part of the palaeozoic-mesozoic allochthonous series. recently, hrvatović (2006) interpreted this zone as a part of the dinaride ophiolitic mélange. triassic pillow basalt series and the limey peperitic facies rocks are important constituents of both ophiolitic mélange occurrences. in the kalnik mts., recent studies suggested a neotethyan rifting related origin for the pillow basalts (palinkaš et al., 2000, 2008, kiss et al. 2012). at vareš, controversy surrounds interpretations of the origins of the rock. trubelja et al. (2004) concluded subduction related formation, while pamić (1984), karamata et al. (2000) and kiss et al. (2012) presented observations strongly supporting a riftrelated origin of the basaltic volcanism. localities in the hellenides the avdella mélange formation (fig. 1.) of jurassic age occurs in nw greece, within the pindos zone of the hellenides. the mélange with basaltic and other magmatic and sedimentary blocks is one of the five main tectonostratigraphic units of the pindos zone. the accretionary mélange forms a nappe below the pindos ophiolites (jones & robertson, 1991, rassios & moores, 2006) occurring in the vicinity of the village of avdella (n 40.007489, e 21.125159) in the stragopetra mts. based on the geochemistry of the pillow basalt blocks, jones & robertson (1991) argued that their formation took place in a mid-oceanic ridge environment, while kovács et al. (2010), kiss et al. (2012) and ozsvárt et al. (2012) suggested a neotethyan rifting related origin and triassic age (from fossil evidence in the limestones of the peperitic facies). correlation possibilities the current geodynamic models correlate the darnó unit with the triassic submarine basalt occurrences in the northwestern parts of the dinarides (dimitrijević et al., 2003, haas & kovács, 2001, kovács et al., 2010, haas et al. 2011, kiss et al., 2008, 2010, 2012). geological correlation summarised in dimitrijević et al. (2003) and haas et al. (2011) also support the dinaridic origin of the submarine magmatic and sedimentary rocks of the szarvaskő unit. however, results of kovács et al. (2010) and kiss et al. (2012) have also extended this correlation to localities in the hellenides. thus, the studied ne hungarian, dinaridic and hellenidic units represent remnants of the neotethyan accretionary complexes (dimitrijević et al., 2003, haas et al., 2011). the ne hungarian ones were transported from the northwestern dinarides to the current position along the mid-hungarian lineament by approx. 400 km of horizontal displacement during the alp-carpathian collisional processes (csontos & vörös, 2004, schmid et al., 2008). 3. study methods field studies were carried out in quarries and at outcrops of the darnó unit and szarvaskő unit (ne hungary), kalnik mts. (n croatia), vareš area (central bosnia-herzegovina) and in the stragopetra mts. (n greece). field recognition of volcanic facies and representative sampling of relatively fresh and hydrothermally altered rocks were the focus of field studies. vol. 69/1 42 thin-section petrographic study of samples with emphasis on observation of the distinctive textures of rocks and hydrothermal alteration mineral assemblages was undertaken. an amray 1830 sem-eds instrument with pv9800 type detector at the department of petrology and geochemistry of the eötvös loránd university was also used for the petrographic characterisation of mineral assemblages. eds analyses were completed with focused electron beam with 20 kv accelerating potential, 1 na beam current and 100s detection time. the instrument was calibrated using well known natural and synthetic standards. the average detection limits were 0.1 wt% for the analysed elements. x-ray powder diffraction (xrpd, at the department of mineralogy of the eötvös loránd university) aided determination of other mineral phases. a siemens d-5000 type diffractometer with bragg-brentano geometric emission (θ-θ working method, cu kα (λ=0.154178 nm), secondary graphite crystal monochromator and scintillation detector was used together with the eva software (bruker-axs diffrac plus) for data analysis. chlorite compositions from different textural settings facilitated temperature determination of fluid/rock interaction via wavelength dispersive (wds) electron microprobe analyses (epma). calibrations by kranidiotis & maclean (1987), chatelineau & izquierdo (1988) and zang & fyfe (1995) aided determination of chorite formation temperatures, depending on the measured al(iv) and xfe values of the individual crystals. these methods bear about 20°c uncertainty of formation temperature estimation. the epma analyses of chlorite were performed at the carleton university (ottawa, canada) and at the masaryk university (brno, czech republic). elemental distribution maps of selected basalt samples were prepared at the eugen stumpfl laboratory of the university centre of applied geoscience, university of leoben, austria. at the carleton university, the quantitative analyses of chlorite were completed using 15kv accelerating voltage and a beam current of 20 na. the detection limits were as follows: sio2, tio2, cr2o3, mgo and cl 0.03 wt%; al2o3, k2o, cao and na2o 0.02 wt%; mno, nio and f 0.04 wt%; feo 0.05 wt%. at the university of leoben, elemental mapping was performed in wds mode, with 15 kv accelerating voltage and 10 na beam current. at the masaryk university, cameca sx 100 type instrument with 15 kv accelerating potential and a beam current of 10 na was used for determination of the major element compositions of chlorite. the detection limits were as follows: 0.06 wt% for na, 0.04 wt% for si and v, 0.035 wt% for al, 0.045 wt% for mg and k, 0.03 wt% for ca, cr, cl and ti, 0.12 wt% for ba, 0.08 wt% for fe and ni, 0.07 wt% for mn and f and 0.2 wt% for zn. a suite of reliable natural and synthetic minerals and compounds were used as calibration standards at all laboratories. fluid inclusion petrography and microthermometry were carried out at the department of mineralogy, eötvös loránd university, on 80-100 μm thick, double polished sections of hydrothermal calcite from various volcanic and hydrothermal facies of basalt. equipment was a chaixmeca-type and linkam ft-ir 600 type heating-freezing stage mounted on an olympus bx-51 type polarizing microscope with 1000 x opical magnification capability. precision of the microthermometric measurements was ±0.1 oc below 0 oc, and ±1 oc above it. co2 and h2o synthetic fluid inclusions were used for all equipment calibration. interpretation of microthermometric data involved using a macro program in ms excel, developed in visual basic environment by the first author, using the methods of hall et al. (1988), naden (1996), potter & clynne (1978) and zhang & frantz (1987). geochemical analysis of rock samples were carried out at the laboratory of the als laboratory group (vancouver, canada) and in the geochemical laboratory of the hungarian geological institute. geochemical data (8 samples) were published in kiss et al. (2012) and 19 samples were analysed in this study. the als laboratory used icp-aes to determine the major elements, pt, pd and au, and icp-ms to analyse the trace elements. detection limits and analytical procedures are described in the official booklet of als1. the hungarian geological institute analysed the major elements with icp-aes, the trace elements with icp-ms or icp-aes, and hg content with aas. detection limits and analytical procedures are described in the accreditation documentation of the laboratory2. major and trace element data were interpreted using the petrograph software (petrelli et al., 2005). mass transfer calculations (mtc) were also performed, according to the method described in grant (1986), maclean & kranidiotis (1987), brauhart et al. (2001) and ulrich & heinrich (2002). 4. results field study six different volcanic facies can be distinguished in submarine lava flows: (1) coherent basalt, (2) closely packed pillow basalt, (3) peperitic pillow basalt, (4) in situ hyaloclastite breccia, (5) pillow fragmented hyaloclastite breccia and (6) isolated pillow breccia facies (palinkaš et al., 2008, see also fig. 16. below). the quarry at hruškovec exposes all six distinguishable volcanic facies of a submarine lava flow (palinkaš et al., 2008, kiss et al., 2008). it was therefore used as the basis of comparison for volcanological features in other similar submarine basaltic volcanic centres. its characteristic features are summarised in the above referenced citations, and not repeated here. the closely packed pillow, peperitic pillow, in situ hyaloclastite and the pillow fragmented hyaloclastite breccia facies were all detected in five studied quarries and several outcrops in the darnó unit. the studied quarry and the surveyed smaller natural and artificial outcrops in the szarvaskő unit expose three main volcanic facies: closely packed pillow, peperitic pillow and pillow fragmented hyaloclastite breccia facies. the quarry and several small outcrops in the vareš-smreka area expose the closely packed pillow facies and the peperitic pillow facies. three large artificial outcrops (a quarry and two roadcuts) and two smaller natural outcrops were studied in detail on the western, southern and southeastern slopes of the stragopetra mts. these exposures contain closely packed pil1available at: http://www.alsglobal.com/our-services/minerals/geochemistry/downloads 2accreditation number: nat-1-1302/2012 kiss et al.: hydrothermal processes related to some triassic and jurassic submarine basaltic complexes in northeastern hungary... 43 low facies, but the most abundant is the peperitic pillow facies. petrography detailed petrographic investigations, coupled with xrpd and sem-eds analyses as well as epma elemental mapping revealed mineralogical, petrographic and textural similarities and differences between the studied localities. results are summarised in table 1. and presented below, highlighting the common and different features recognised in the four volcanic facies occurring in the study area. the closely packed pillow facies the closely packed pillow facies, formed around the coherent pillows of the lava flow, as a moderately distal facies in relation to the eruption centre (palinkaš et al., 2008). they are composed of grey, greyish green, or reddish grey basaltic pillows 30-100 cm in diameter at every locality (fig. 2a). the texture of the basalt is sphaerolitic, variolitic or interstertal. at the triassic localities, the rock is composed mostly of altered plagioclase laths and 40-50% microcrystalline and glassy groundmass, while the occurrence of clinopyroxene laths is very rare (fig. 2b,c). porphyry texture occurs only rarely, when the weakly altered (argillitised) plagioclase occur in two size groups: > 1 mm and 0.1 0.4 mm. the sem-eds studies proved that the plagioclase is predominantly albite in composition (table 2, fig. 3a). elemental mapping by epma revealed that these crystals contain more na and less ca closer to the margins of the pillows (where sphaerolitic-variolitic texture dominates), than in their inner parts (where variolitic-intersertal texture dominates) (fig. 4a-i). the augitic pyroxene in the triassic basalts is rather homogeneous (morimoto, 1989; table 3, fig. 3b). calcite, chlorite and opaque mine ral pseudomorphs after the 0.5-0.8 mm large olivine phenocrysts are common in the triassic basalts. the groundmass is altered to chlorite, clay minerals, calcite, haematite and titanite. the xrpd analyses revealed the presence of chlorite-smectite, chlorite-illite interlayering, celadonite and smectite. disseminated pyrite, figure 2. macroscopic and microscopic photos of the observed facies. a, closely packed pillow with abundant, mostly calcite-filled jig-saw veins and a small amount of interpillow hyaloclastite breccia (nagy-rézoldal quarry, darnó unit, hungary). b, intersertal textured triassic basalt with small, chlorite filled amygdales (nagy-rézoldal quarry, darnó unit, hungary). c, older, higher temperature quartz and prehnite filled cooling crack is cut by a younger, lower temperature calcite vein in a triassic basalt (rm-131 drillcore, darnó unit, hungary). d, porphyryc textured jurassic basalt with coarse grained pyroxene showing compositional zonation. the rock is cut by a thin, cooling related calcite vein (egerbakta quarry, szarvaskő unit, hungary). e, chaotic mingling of basalt and pinkish limestone from a triassic peperitic facies (stragopetra, greece). f, chaotic mingling of basalt and limestone from a triassic peperitic facies. the limestone contains basalt clasts, chloritised glassy shards as well as pieces of plagioclase laths (bájpatak quarry, darnó unit, hungary). g, pillow fragmented hyaloclastite breccia at a jurassic basalt location (egerbakta quarry, szarvaskő unit, hungary). h, glassy basaltic clast in a triassic hyaloclastite breccia. textural variation from the glassy, through sphaerolitic till variolitic is observable, while the cementing hydrothermal material is mostly calcite (rm-131 drillcore, darnó unit, hungary). abbreviations: b: basalt, cal: calcite, chl: chlorite, g: glass, hem: haematite, l: limestone, m: matrix, pl: plagioclase, px: pyroxene, q: quartz, preh: prehnite. vol. 69/1 44 triassic jurassic c lo se ly p ac ke d pi llo w b as al t rock texture sphaerolitic, variolitic, rarely intersertal porphyric intersertal main minerals plagioclase, rare clinopyroxene (augite) plagioclase, clinopyroxene (augite) other components pseudomorphs after olivine, pyrite, chalcopyrite, hematite, bornite, titanite pyrite, chalcopyrite alteration groundmass chlorite, chlorite-smectite and chlorite-illite interlayering, celadonite, smectite, calcite plagioclase albite, partly atered to clay minerals albite hydrothermal infillings amygdales, jig-saw veins, thin veinlets, former feeding channels, mineral bands of pyjamas-type pillows, interpillow hyaloclastite thin veinlets, interpillow hyaloclastite hydrothermal minerals chlorite, quartz, calcite, laumontite, haematite, epidote, prehnite chlorite, quartz, calcite, epidote, prehnite pe pe ri tic p ill ow rock basalt similar, than in the closely packed pillow similar, than in the closely packed pillow sedimentary rock red micritic limestone black aleurolite sedimentary rock composition calcite, bioclasts, plagioclase, glassy shards, pyroxene quartz, chalcedony, albite (alteration products) amount of sedimentary rock 50-70% 20-30% alteration groundmass haematite quartz, chalcedony, albite hydrothermal infillings thin veinlets, jigsaw veins, amygdales thin veinlets hydrothermal minerals calcite, chlorite, haematite, prehnite, laumontite calcite, quartz, chlorite, prehnite, albite in si tu a nd pi llo w fr ag m en te d hy al oc la st ite rock breccia clasts pillow basalt, fractured basalt, glass shards, micritic limestone fractured basalt, glass shards breccia matrix quartz, chlorite, calcite, prehnite, pumpellyite quartz, chlorite, prehnite and pumpellyite alteration basalt clasts haematite, chlorite chlorite table 1. petrographical characteristics of the triassic and jurassic rocks. chalcopyrite, haematite (also pseudomorphs after pyrite) and bornite also occur in the basalt. fluid/rock ineteraction processes and percolation of upheated sea-water in the piles of triassic basaltic lava flows, resulted in precipitation of hydrothermal minerals filling the amygdales (0.1-5 mm in size), cooling of related jig-saw veins of 1-3 mm thickness, infilling of the 0.1-0.5 mm thin cross-cutting veins and former internal feeding channels of the lava. the interpillow hyaloclastite breccia is also cemented by hydrothermal minerals (fig. 2a, b, c). the thin veinlets and the smaller (0.1-1 mm) amygdales contain only the oldest mineral paragenesis, while the bigger (1-5 mm) amygdales, the mineral bands in the pyjama-type pillows, the former feeding channels, and the jig-saw type veins also contain the older hydrothermal mineral phases along their walls, with younger mineral infillings of different composition in their central parts. the small amygdales are generally infilled with chlorite (fig. 2b), but sometimes quartz also occurs. larger amygdales are mostly infilled with calcite and lesser amounts of chlorite and quartz. the thin veinlets contain chlorite, quartz, epidote, calcite and prehnite, whereas the jig-saw type veins are mostly infilled with a calcite-quartz-chlorite assemblage (fig. 2c). the mineral bands of the pyjama-type pillows contain mostly calcite with a small amount of haematite, quartz, chlorite and laumontite. infillings of the former feeding channels are mostly calcite. the 0.5-5 cm glassy shards of the interpillow hyaloclastite breccia are cemented with a mixture of chlorite, calcite, quartz, epidote and prehnite at all the studied localities. alteration features in the jurassic basalt slightly differ from the peculiarities of the triassic basalt described above. it is generally characterised with a porphyric-intersertal texture and contains more clinopyroxene and lesser amounts of microcrystalline and glassy groundmass (fig. 2d). the weakly altered (argillitised) plagioclase and fresh pyroxene phenocrysts occur in two size groups: > 1 mm and 0.1 0.4 mm. the semeds studies proved that the plagioclase is predominantly kiss et al.: hydrothermal processes related to some triassic and jurassic submarine basaltic complexes in northeastern hungary... 45 table 2. results of the sem-eds studies (plagioclase analyses). na2o al2o3 sio2 k2o cao total na al si k ca total egerbakta q. (szarvaskő u.) porphyry albite mean (n=5) 10.79 19.77 69.04 b.d.l. 0.12 99.63 0.91 1.02 3.01 b.d.l. 0.01 4.94 st.dev. 0.39 0.16 0.37 b.d.l. 0.00 0.43 0.03 0.01 0.01 b.d.l. 0.00 0.02 groundmass albite mean (n=3) 10.70 19.90 68.79 b.d.l. 0.20 99.46 0.90 1.02 3.00 b.d.l. 0.01 4.93 st.dev. 0.28 0.16 0.21 b.d.l. 0.00 0.40 0.02 0.01 0.01 b.d.l. 0.00 0.02 hruškovec q. (kalnik mts.) groundmass albite mean (n=5) 9.92 20.01 69.23 b.d.l. 0.44 99.61 0.84 1.03 3.01 b.d.l. 0.02 4.90 st.dev. 0.33 0.26 0.38 b.d.l. 0.19 0.31 0.03 0.01 0.01 b.d.l. 0.01 0.02 mély valley q. (darnó u.) porphyry albite mean (n=6) 10.51 20.22 68.13 b.d.l. 0.54 99.40 0.89 1.04 2.98 b.d.l. 0.03 4.95 st.dev. 0.34 0.15 0.53 b.d.l. 0.17 0.29 0.03 0.01 0.01 b.d.l. 0.01 0.02 groundmass albite mean (n=4) 9.86 20.13 68.92 b.d.l. 0.67 99.58 0.83 1.03 3.00 b.d.l. 0.03 4.90 st.dev. 0.43 0.34 0.40 b.d.l. 0.09 0.28 0.04 0.01 0.01 b.d.l. 0.00 0.03 nagy-rézoldal q. (darnó u.) groundmass albite mean (n=2) 10.03 20.93 67.37 b.d.l. 1.48 99.81 0.85 1.08 2.95 b.d.l. 0.07 4.94 st.dev. 0.27 0.41 1.03 b.d.l. 0.61 0.25 0.03 0.02 0.04 b.d.l. 0.03 0.04 stragopetra mts. porphyry albite (n=1) 10.32 19.50 68.01 b.d.l. 2.19 100.02 0.87 1.01 2.98 b.d.l. 0.10 4.96 groundmass albite (n=1) 9.34 20.51 68.00 b.d.l. 1.64 99.49 0.79 1.06 2.97 b.d.l. 0.08 4.90 vareš q. porphyry albite mean (n=6) 10.11 20.06 68.91 b.d.l. 0.49 99.56 0.85 1.03 3.01 b.d.l. 0.02 4.91 st.dev. 0.55 0.18 0.50 b.d.l. 0.12 0.28 0.05 0.01 0.01 b.d.l. 0.01 0.04 groundmass albite mean (n=2) 10.35 20.16 68.68 0.31 0.46 99.80 0.87 1.04 2.99 0.02 0.02 4.93 st.dev. 0.18 0.37 0.47 0.00 0.08 0.02 0.01 0.02 0.01 0.00 0.00 0.01 analyses are given in mass%, while the cation numbers are calculated for 8 oxygene b.d.l.: below detection limit; q.: quarry u.: unit egerbakta quarry (szarvaskő unit) nagy-rézoldal quarry (darnó unit) vareš quarry porphyry augite (zoned-1) porphyry augite (zoned-2) porphyry augite groundmass augite later diopside groundmass augite groundmass augite mean (n=2) st.dev. mean (n=2) st.dev. (n=1) mean st.dev. mean (n=2) st.dev. mean (n=4) st.dev. mean (n=4) st.dev. mgo 17.35 0.01 19.42 0.23 17.01 16.10 0.52 8.72 0.12 10.10 0.97 15.85 0.29 al2o3 5.40 0.24 3.56 0.15 3.98 6.25 0.23 2.00 0.00 8.45 0.76 4.90 0.40 sio2 50.71 0.18 52.77 0.13 51.87 49.66 0.81 51.68 0.67 43.11 1.10 50.87 0.21 cao 20.22 0.19 18.41 0.42 20.28 19.53 0.19 24.06 0.62 21.84 0.26 20.24 0.50 tio2 0.51 0.00 0.19 0.03 0.38 0.89 0.05 b.d.l. b.d.l. 5.31 0.53 1.07 0.10 cr2o3 0.76 0.11 0.38 0.03 0.32 0.19 0.00 0.08 0.00 0.19 0.00 0.31 0.14 mno 0.19 0.01 0.20 0.01 0.26 0.26 0.01 0.99 0.23 0.18 0.05 0.23 0.02 feo 4.74 0.04 5.00 0.00 5.02 7.29 0.95 13.10 0.39 10.98 1.14 6.61 0.69 total 99.86 0.17 99.92 0.46 99.12 100.05 0.42 99.57 0.33 100.01 0.69 100.01 0.20 mg 0.95 0.01 1.05 0.01 0.93 0.89 0.02 0.50 0.00 0.58 0.05 0.87 0.02 al 0.24 0.01 0.16 0.01 0.17 0.27 0.01 0.09 0.00 0.38 0.03 0.21 0.02 si 1.86 0.01 1.91 0.00 1.91 1.83 0.01 1.99 0.03 1.65 0.02 1.87 0.01 ca 0.80 0.01 0.71 0.01 0.80 0.77 0.00 0.99 0.03 0.90 0.02 0.80 0.02 ti 0.01 0.00 0.01 0.01 0.01 0.03 0.01 b.d.l. b.d.l. 0.15 0.02 0.03 0.00 cr 0.02 0.00 0.01 0.00 0.01 0.01 0.00 0.00 0.00 0.01 0.00 0.01 0.01 mn 0.01 0.00 0.01 0.00 0.01 0.01 0.00 0.04 0.01 0.01 0.01 0.01 0.00 fe 0.15 0.01 0.15 0.00 0.15 0.23 0.04 0.42 0.01 0.35 0.04 0.20 0.02 total 4.02 0.01 4.00 0.00 3.99 4.02 0.01 3.98 0.01 4.01 0.01 3.99 0.01 analyses are given in mass%, while the cation numbers are calculated for 6 oxygene b.d.l.: below detection limit table 3.results of the sem-eds studies (pyroxene analyses). vol. 69/1 46 type of infilling locality number of measurements* th (mean,°c) scatte ring (°c) te (mean, °c) scatte ring (°c) tm (mean, c) scatte ring (°c) salinity (nacl equiv. wt%) scattering (nacl equiv. wt.%) amygdales of the closely packed pillow hosszú valley quarry (darnó unit) 18 101 11 -20.4 -2.73 0.36 4.54 0.55 nagy-rézoldal quarry (darnó unit) 32 136 19 -21.6 0.65 -2.10 0.40 3.49 0.62 pyjamas-type closely packed pillow hosszú valley quarry (darnó unit) 25 91 14 -21.3 0.82 -2.70 0.42 4.49 0.65 mély valley quarry (darnó unit) 37 92 13 -22.2 0.82 -3.30 1.00 5.33 1.50 jig-saw veins of the closely packed pillow hosszú valley quarry (darnó unit) 22 110 18 -21.3 -2.40 0.23 3.95 0.36 interpillow hyaloclastite breccia hosszú valley quarry , earlier calcite (darnó unit) 10 98 16 -1.90 0.14 3.20 0.23 4 70 5 -2.00 0.17 3.40 0.28 pillow fragmented hyaloclastite breccia hosszú valley quarry, later calcite (darnó unit) 27 88 13 -1.79 0.22 3.04 0.36 *: reveals to the no. of th measurements. te and tm data may differ, see text for explanation. th: homogenisation temperature te: eutectic temperature tm: final melting temperature table 4. results of the fluid inclusion study. albite in composition (table 2, fig. 3a), whereas the augite phenocrysts show compositional zoning due to slight variation in the ca and mg content (morimoto, 1989; table 3, fig. 3b). primary hydrothermal infillings are absent in the basalt, though the groundmass is altered to chlorite, clay minerals and calcite. disseminated pyrite and chalcopyrite also occur in the altered ground mass. the xrpd analyses revealed the prese nce of chlorite-smectite, chlorite-illite interlayered clay minerals, celadonite and smectite. the jurassic pillow basalt contains neither amygdales, nor jig-saw veins. only a limited amount of hydrothermal mineral-cemented interpillow hyaloclastite breccia and cooling related thin, short veinlets occur (fig. 2d). the peperitic pillow facies the peperitic pillow facies, which formed where the lava rocks were mixed with water soaked sediment (palinkaš et al., 2008, skilling et al., 2002), belong to the so-called blocky peperite subtype (skilling et al., 2002) at all the studied localities. this volcanic facies is characterised by 10-50 cm large basalt fragments (sometimes of pillow shape) in the matrix (5070%), which is a reddish limestone of triassic age (fig. 2e), whereas it is a fine grained, black siliciclastic rock in peperites of jurassic age. the so-called fluidal peperite subtype (skilling et al., 2002) is locally present (fig. 2e) and the transition from the closely packed pillow to the peperitic facies also occurs in the triassic localities. the sedimentary material forms not only the matrix of the basalt fragments, but infiltrates into the cooling cracks of the basalt or forms a chaotic mixture with it (fig. 2f). where mixing of the volcanic material with unconsolidated sediments is the most chaotic, a high amount hydrothermal minerals, such as calcite, quartz, chalcedony, chlorite, pumpellyite and laumontite is present as veinor cavity-filling. the texture of the triassic limestone is generally micritic, but it locally contains bioclasts and weakly preserved radiolarians, as well as fragments of bivalve shells. the carbonate matrix characteristically contains disseminated minerals and fragments of basaltic origin (mostly plagioclase laths, glassy shards, rarely pyroxene, fig. 2f). the limestone also contains disseminated, fine grained (below 3 µm) haematite laths and plates. the siliciclastic sedimentary rock in the jurassic peperites is completely altered to a fine grained mass of albite-quartz-chalcedony, but the original sedimentary textural features are preserved and resemble aleurolite. in both cases, the mineralogical and textural features of basalt fragments admixed to the sediments are very similar to the basalt of the closely packed pillow facies, though more glassy parts, as well as haematitisation are more common in the triassic basalts. the thin hydrothermal veinlets contain calcite, prehnite, quartz and chlorite in both occurrences. in addition, albite also occurs in the jurassic peperite. the amygdales in the triassic basalt contain calcite, chlorite and haematite, while the jig-saw veins are filled mostly with calcite, with some chlorite, laumontite and prehnite. the in situ hyaloclastite breccia and the pillow fragmented hyaloclastite breccia facies in the in situ hyaloclastite breccia facies only observed in localities of triassic age, smaller fractured basalt pillows (20-30 cm), and slightly disproportional pillow fragments, are cementkiss et al.: hydrothermal processes related to some triassic and jurassic submarine basaltic complexes in northeastern hungary... 47 ed by hydrothermal calcite and cogenetic chlorite and pyrite. glassy basalt shards and occasional pieces of reddish limestone fragments also occur. this facies forms close to the seafloor, immediately around the closely packed pillow facies (palinkaš et al., 2008). it is a transitional facies between the closely packed pillow and the more distal pillow fragmented hyaloclastite breccia facies. the latter is observed at both triassic and jurassic localities and it contains more matrix and less and smaller basalt fragments than the in situ breccia (fig. 2g). the hydrothermal cement is composed of quartz, chlorite, calcite, prehnite and pumpellyite. basalt in both breccia facies is characterised with the same features as described above, however, more glassy textures are also common (fig. 2h). the basalt is often strongly chloritised, but in the case of the triassic ones, haematitisation also occurs. fluid inclusion study fluid inclusion studies were performed on calcite from the hydrothermal infillings. microthermometric data from some triassic and jurassic localities are summarised in earlier publications (kiss et al., 2008, 2011, 2012). here we present microthermometric data for the jig-saw veins, interpillow hyaloclastite breccia, the pillow fragmented hyaloclastite breccia and some new closely packed pillow occurrences. interpretation is based on these new data together with that previously published. in all cases, the calcite often shows a spongy texture, making observation of the peculiarities of fluid inclusions difficult. primary fluid inclusions are characterised by a negative crystal shape and are very rare, occurring in isolation in the inclusion poor parts of calcite or in populations of randomly distributed inclusions forming ‘3d clouds” in some parts of the host minerals, far from the cleavage-plane related secondary fractures. the size of primary inclusions is generally between 4 10 µm, while the phase ratio with 95-90% liquid phase and 5-10% vapour phase appear to be constant, suggesting homogenous entrapment from a homogenous parent fluid. the small size of the inclusions, as well as the generally occurring metastable melting during freezing runs resulted in a low amount of microthermometry data. figures 5-8. and table 4. present the results obtained from the amygdale filling calcite, the mineral bands of the pyjamatype pillows, the jig-saw veins, the interpillow hyaloclastite breccia as well as the pillow fragmented hyaloclastite breccia of the triassic localities. chlorite thermometry temperatures of fluid-rock interaction were estimated on the basis of chlorite thermometry from samples of triassic and jurassic age. compositions of chlorite occurring in the groundmass of basalt, forming pseudomorphs after olivine, infilling amygdales and veins and confined to the cement of the interpillow and the pillow fragmented hyaloclastite breccia, were determined by electron microprobe analyses. results indicate that all chlorite samples belong to the type i, mg-chlorite group, defined by zane & weiss (1998). table 5. shows the compositions and calculated formation temperatures of chlorite crystals of different textural positions (chatelineau & izquierdo, 1988 and zang & fyfe, 1995). geochemical features of the fluid/rock interaction the results of the analyses for most major elements (ca, mg, na, k, fe, mn) as well as some precious and base metal trace elements (e.g. au, cu, zn) and the lile group of trace elements show highly variable amounts and scattering on the spider diagram. in contrast, si, al, cr, ti, the hfs and ree group of trace elements do not scatter significantly, when comparing the less and more altered samples in our database (table 6 and fig. 9 a, b, c, d). as a consequence, the spider diagram of the ree shows two narrow, distinguishable fields of results, one for the triassic and one for the jurassic basalts (fig. 9 c, d). enrichment in lree, thus a higher la/sm ratio (above 1) is characteristic for the triassic basalts, while a lower la/sm ratio (around or below 1) is typical for the jurassic basalts indicating their different origins (wilson, 1989). this topic has been exhaustively discussed in previous publications (see e.g. kiss et al., 2011, 2012 and references therein), therefore the data is evaluated herein terms of the fluid/rock interactions, with daigrams presented only for comparison with the earlier results. discrimination diagrams based on rather immobile elements by pearce & cann (1973) and meschede (1986) prove the different geotectonic position of the basaltic rocks of triassic and jurassic ages (fig. 9ef). enrichment in the incompatible elements in the triassic basalt shows relatively low partial melting, which together with the high zr/y ratio (generally above 4) supports the idea that this basalt is not related to mid-oceanic ridges (sun & mcdonough, 1989). geochemical analyses of the peperitic limestone are shown in table 7. mass transfer calculation (mtc, grant, 1986, maclean & kranidiotis, 1987, brauhart et al., 2001, ulrich & heinrich, 2002), which is widely accepted in ore deposit exploration, can also efficiently be used for quantitative modelling of element mobilisation occurring during submarine hydrothermal fluid-rock interaction processes. the calculations may be done on different scales; within a single pillow (from its centre to its margin), within a volcanic facies (from less to more altered parts) and for comparison of two or more volcanic facies. the present study shows the preliminary results of these calculations; a few examples for all these different scales. according to the mtc method, after determining the freshest samples in the data set, the most immobile components have to be determined. in the present study, we used the isocon method and thus y, zr, nb and tio2 were found to be the most immobile components. then the residual compositions of the altered samples were calculated, followed by determination of the gains/losses of mass. only data sets originating from the same locality (thus rocks from the same protoliths) were compared and used for mtc calculations (fig. 10). generally, a decrease in sio2, cao and the analysed metals and a slight increase in na2o and k2o are observable independently of the scale of observation. special features may be also identified (e.g. the amount of mass transfered is significantly higher when heading to the peperitic facies; see fig. 10). vol. 69/1 48 hosszú valley quarry (darnó unit) mély valley quarry (darnó unit) groundmass chlorite chlorite in amygdales chlorite in the matrix of the pillow fragmented hyaloclastite breccia chlorite in pseudomorphs after olivine chlorite in the matrix of the interpillow hyaloclastite breccia chlorite in thin veinlets of the closely packed pillow facies (type 1) chlorite in thin veinlets of the closely packed pillow facies (type 2) (n=1) mean (n=2) st.dev. mean (n=6) st.dev. mean (n=2) st.dev. mean (n=6) st.dev. mean (n=8) st.dev. mean (n=4) st.dev. sio2 29.03 30.16 0.15 29.86 0.30 30.86 1.15 30.35 1.64 29.57 0.84 33.35 1.48 tio2 0.08 0.02 0.01 0.04 0.04 0.51 0.70 0.02 0.00 0.08 0.02 0.11 0.01 al2o3 17.56 17.00 0.14 18.09 0.21 17.42 0.36 19.61 0.89 19.20 0.54 18.56 0.55 cr2o3 0.11 0.02 0.00 0.01 0.01 0.02 0.00 0.01 0.01 0.08 0.02 0.11 0.02 feot 18.65 17.92 0.20 20.39 0.22 19.39 1.45 13.77 0.73 17.26 0.54 15.69 0.48 mno 0.38 0.45 0.01 0.29 0.03 0.26 0.07 0.61 0.04 1.53 0.09 1.62 0.16 mgo 19.59 19.70 0.29 18.79 0.27 18.62 1.16 21.44 0.81 18.92 0.93 18.19 0.23 cao 0.33 1.37 0.18 0.38 0.12 1.54 1.59 0.44 0.10 0.55 0.42 0.42 0.09 na2o 0.05 0.06 0.07 0.06 0.02 0.10 0.05 0.05 0.02 n.a. n.a. n.a. n.a. k2o 0.06 0.05 0.00 0.07 0.02 0.13 0.06 0.37 0.59 0.03 0.01 0.09 0.04 v2o3 b.d.l. 0.05 0.01 0.02 0.01 0.01 0.00 0.01 0.01 n.a. n.a. n.a. n.a. nio 0.02 0.08 0.06 0.05 0.03 0.05 0.00 0.21 0.05 n.a. n.a. n.a. n.a. zno b.d.l. 0.17 0.06 0.13 0.07 0.16 0.06 0.15 0.09 n.a. n.a. n.a. n.a. cl 0.02 0.02 0.00 0.01 0.00 0.01 0.00 0.02 0.01 0.02 0.01 0.02 0.01 f b.d.l. b.d.l. b.d.l. 0.01 0.01 0.05 0.00 0.01 0.01 n.a. n.a. n.a. n.a. total 85.88 87.00 0.45 88.13 0.45 89.06 0.98 86.99 1.73 87.24 0.46 88.13 1.83 cation numbers calculated for 14 oxygene: si 3.01 3.08 0.00 3.04 0.03 3.10 0.06 3.03 0.09 3.00 0.07 3.29 0.07 al (iv) 0.99 0.92 0.00 0.96 0.03 0.90 0.06 0.97 0.09 1.00 0.07 0.71 0.07 total (iv) 4.00 4.00 0.00 4.00 0.00 4.00 0.00 4.00 0.00 4.00 0.00 4.00 0.00 al (vi) 1.16 1.13 0.00 1.20 0.02 1.16 0.06 1.33 0.13 1.30 0.09 1.45 0.06 ti 0.01 0.00 0.00 0.00 0.00 0.04 0.05 0.00 0.00 0.01 0.00 0.01 0.00 cr 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.00 fe 1.62 1.53 0.03 1.73 0.02 1.63 0.15 1.15 0.08 1.47 0.05 1.29 0.05 mn 0.03 0.04 0.00 0.03 0.00 0.02 0.01 0.05 0.00 0.13 0.01 0.13 0.01 mg 3.03 3.00 0.02 2.85 0.04 2.79 0.22 3.19 0.18 2.87 0.15 2.68 0.07 ca 0.04 0.15 0.02 0.04 0.01 0.16 0.17 0.05 0.01 0.06 0.04 0.04 0.01 k 0.01 0.01 0.00 0.01 0.00 0.02 0.01 0.05 0.07 0.00 0.00 0.01 0.01 na 0.01 0.01 0.01 0.01 0.00 0.02 0.01 0.01 0.00 n.a. n.a. n.a. n.a. v b.d.l. 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 n.a. n.a. n.a. n.a. ni 0.01 0.03 0.02 0.02 0.01 0.02 0.00 0.07 0.02 n.a. n.a. n.a. n.a. zn b.d.l. 0.05 0.02 0.04 0.02 0.05 0.02 0.04 0.03 n.a. n.a. n.a. n.a. total (vi) 5.91 5.88 0.01 5.88 0.02 5.84 0.12 5.82 0.07 5.84 0.07 5.62 0.06 vacancy 0.09 0.12 0.01 0.12 0.02 0.16 0.12 0.18 0.07 0.16 0.07 0.38 0.06 xfe 0.34 0.32 0.01 0.37 0.00 0.35 0.02 0.26 0.01 0.32 0.01 0.31 0.00 mg+fettot 4.65 4.54 0.00 4.58 0.05 4.42 0.38 4.34 0.26 4.33 0.19 3.97 0.11 al+vacancy 1.25 1.26 0.00 1.33 0.04 1.32 0.18 1.51 0.20 1.46 0.15 1.82 0.12 nomenclatura of zane and weiss (1998): type 1. 1 1. 1. 1. 1. 1. name* mg mg mg mg mg mg mg thermometry: t (oc) (c&i-1988) 256 233 2 252 30 259 22 167 23 t (oc) (z&f-1995) 221 5 216 0 table 5. results of the epma quantitative analyses of the chlorite crystals. analyses are given in mass% *: mg: magnesium chlorite thermometry based on c&i-1988: chatelineau and izquierdo, 1988; z&f-1995: zang and fyfe, 1995 **: though slightly differers from the criteria of the given method, based on frimmel (1997) the data still can be used for calculations. (n.a.: not available; b.d.l.: below detection limit, st.dev.: standard deviation) ***: only one analyses fit into the criteria of the thermometry methods, therefore mean and standard deviation were not calculated. kiss et al.: hydrothermal processes related to some triassic and jurassic submarine basaltic complexes in northeastern hungary... 49 nagy-rézoldal quarry (darnó unit) stragopetra mts. chlorite in small (only chlorite filled) amygdales chlorite in small amygdales groundmass chlorite chlorite in pseudomorphs after olivine chlorite in thin veinlets of the closely packed pillow facies chlorite on the rims of the big amygdales chlorite on the rims of the jig-saw veins chlorite in thin veinlets of the closely packed pillow facies mean (n=13) st.dev. mean (n=3) st.dev. mean (n=3) st.dev. mean (n=3) st.dev. mean (n=2) st.dev. mean (n=3) st.dev. mean (n=3) st.dev. mean (n=3) st.dev. sio2 30.53 0.42 30.60 0.25 31.33 1.85 28.94 0.30 29.73 0.73 29.60 0.64 30.10 0.90 26.97 1.74 tio2 0.02 0.01 0.01 0.00 0.03 0.01 0.02 0.01 0.02 0.00 0.01 0.00 0.02 0.00 0.02 0.00 al2o3 16.78 0.42 17.19 0.15 17.09 0.88 18.46 0.45 17.82 0.54 18.14 0.51 18.12 0.77 17.26 0.68 cr2o3 0.09 0.05 0.03 0.01 0.08 0.01 0.11 0.04 0.03 0.01 0.03 0.01 0.02 0.01 0.01 0.00 feot 20.74 0.42 20.98 0.25 22.88 1.40 24.08 0.51 23.41 0.04 23.57 0.09 23.72 0.27 23.25 1.36 mno 0.32 0.05 0.34 0.04 0.26 0.07 0.26 0.03 0.30 0.04 0.26 0.05 0.28 0.04 0.57 0.02 mgo 16.67 0.35 16.63 0.14 16.60 0.16 16.24 0.53 17.04 0.66 16.68 0.35 16.49 0.86 15.14 0.47 cao 0.31 0.03 0.33 0.01 0.40 0.13 0.21 0.03 0.27 0.02 0.22 0.04 0.24 0.04 2.23 2.03 na2o n.a. n.a. n.a. n.a. 0.10 0.08 0.03 0.02 0.06 0.01 0.01 0.00 0.06 0.01 0.06 0.05 k2o 0.01 0.01 0.02 0.01 0.05 0.03 0.09 0.06 0.04 0.00 0.03 0.01 0.15 0.21 0.14 0.13 v2o3 n.a. n.a. n.a. n.a. 0.03 0.02 0.03 0.02 0.01 0.01 0.02 0.01 0.02 0.01 0.03 0.01 nio n.a. n.a. n.a. n.a. 0.07 0.04 0.05 0.01 0.04 0.01 0.06 0.01 0.06 0.04 0.05 0.02 zno n.a. n.a. n.a. n.a. 0.14 0.12 0.10 0.09 0.08 0.06 0.08 0.08 0.06 0.00 0.15 0.07 cl 0.01 0.01 0.02 0.01 0.02 0.01 b.d.l. b.d.l. 0.02 0.00 0.02 0.00 0.01 0.00 0.02 0.01 f n.a. n.a. n.a. n.a. b.d.l. b.d.l. b.d.l. b.d.l. b.d.l. 0.00 b.d.l. b.d.l. b.d.l. b.d.l. 0.01 0.00 total 85.46 0.94 86.13 0.02 89.05 0.44 88.58 0.77 88.79 0.71 88.66 0.49 89.25 0.27 85.82 1.31 cation numbers calculated for 14 oxygene: si 3.20 0.03 3.18 0.02 3.18 0.16 2.99 0.01 3.05 0.04 3.04 0.05 3.07 0.08 2.91 0.12 al (iv) 0.80 0.03 0.82 0.02 0.82 0.16 1.01 0.01 0.95 0.04 0.97 0.04 0.93 0.08 1.09 0.12 total (iv) 4.00 0.00 4.00 0.00 4.00 0.00 4.00 0.00 4.00 0.00 4.00 0.00 4.00 0.00 4.00 0.00 al (vi) 1.27 0.03 1.29 0.01 1.23 0.04 1.23 0.06 1.20 0.04 1.23 0.03 1.24 0.06 1.11 0.14 ti 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 cr 0.01 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 fe 1.82 0.02 1.82 0.03 1.94 0.14 2.08 0.03 2.01 0.02 2.02 0.02 2.02 0.04 2.10 0.12 mn 0.03 0.00 0.03 0.00 0.02 0.01 0.02 0.00 0.03 0.00 0.02 0.00 0.02 0.00 0.05 0.00 mg 2.60 0.04 2.58 0.02 2.51 0.01 2.50 0.06 2.60 0.07 2.55 0.04 2.50 0.12 2.44 0.05 ca 0.03 0.00 0.04 0.00 0.04 0.01 0.02 0.00 0.03 0.00 0.02 0.00 0.03 0.00 0.26 0.24 k 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.01 0.01 0.00 0.00 0.00 0.02 0.03 0.02 0.02 na n.a. n.a. n.a. n.a. 0.02 0.01 0.01 0.00 0.01 0.00 0.00 0.00 0.01 0.00 0.01 0.01 v n.a. n.a. n.a. n.a. 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ni n.a. n.a. n.a. n.a. 0.02 0.01 0.02 0.00 0.01 0.00 0.02 0.00 0.02 0.01 0.02 0.01 zn n.a. n.a. n.a. n.a. 0.04 0.04 0.03 0.03 0.02 0.02 0.02 0.02 0.02 0.00 0.05 0.02 total (vi) 5.76 0.02 5.76 0.01 5.79 0.09 5.88 0.03 5.88 0.00 5.86 0.02 5.85 0.04 5.99 0.13 vacancy 0.24 0.02 0.24 0.01 0.21 0.09 0.12 0.03 0.12 0.00 0.14 0.02 0.15 0.04 0.01 0.13 xfe 0.41 0.00 0.41 0.00 0.43 0.02 0.45 0.00 0.43 0.01 0.44 0.01 0.44 0.01 0.43 0.02 mg+fettot 4.42 0.05 4.40 0.02 4.46 0.15 4.58 0.09 4.61 0.05 4.57 0.03 4.53 0.10 4.54 0.17 al+vacancy 1.51 0.05 1.53 0.02 1.44 0.13 1.35 0.09 1.32 0.05 1.37 0.03 1.39 0.07 1.11 0.27 nomenclatura of zane and weiss (1998): type 1. 1. 1. 1. 1. 1. 1. 1. name* mg mg mg mg mg mg mg mg thermometry: t (oc) (c&i-1988) t (oc) (z&f-1995) 174** 25 185** 4 221*** 223 2 212 4 213 9 215 9 240 26 table 5. results of the epma quantitative analyses of the chlorite crystals. analyses are given in mass% *: mg: magnesium chlorite thermometry based on c&i-1988: chatelineau and izquierdo, 1988; z&f-1995: zang and fyfe, 1995 **: though slightly differers from the criteria of the given method, based on frimmel (1997) the data still can be used for calculations. (n.a.: not available; b.d.l.: below detection limit, st.dev.: standard deviation) ***: only one analyses fit into the criteria of the thermometry methods, therefore mean and standard deviation were not calculated. vol. 69/1 50 d ar nó u ni t sz ar va sk ő u ni t l oc al ity b áj -p at ak n or th q ua rr y h os sz ú va lle y q ua rr y m él y va lle y q ua rr y r es zé l r id ge q ua rr y r m -1 36 dr ill co re e ge rb ak ta q ua rr y r es zé l r id ge n or th , va lle y sz ar va sk ő vi lla ge (n at ur al o ut cr op s) r m -1 36 dr ill co re r oc k ty pe cl os el y pa ck ed pi llo w pe pe ri tic ba sa lt cl os el y pa ck ed pi llo w cl os el y pa ck ed pi llo w cl os el y pa ck ed pi llo w (p ro ve n tr ia ss ic ) ce nt re o f a pi llo w tr an si tio n zo ne o f a pi llo w m ar gi n of a pi llo w pe pe ri tic ba sa lt pr ov en t ri as si c pi llo w ba sa lt cl os el y pa ck ed pi llo w cl os el y pa ck ed pi llo w pe pe ri tic ba sa lt cl os el y pa ck ed pi llo w cl os el y pa ck ed pi llo w cl os el y pa ck ed pi llo w cl os el y pa ck ed pi llo w cl os el y pa ck ed pi llo w cl os el y pa ck ed pi llo w cl os el y pa ck ed pi llo w pr ov en ju ra ss ic pi llo w ba sa lt sa m pl e 1* 2* 1* 2* 1* 1* 2* 3* 4* 1* 1* * 2* * 3* 1* * 2* 1* 2* * 3* * 4* * 5* * 1* si o 2 46 .6 42 .2 37 .8 4 40 .2 41 .0 33 .4 38 .4 51 .6 47 .1 47 .8 54 .3 53 .6 53 .2 51 52 .3 47 .8 49 .4 50 .3 46 .7 49 .3 47 .5 a l 2o 3 15 .6 14 .8 20 .7 53 20 .4 16 .7 23 .2 12 .6 16 .8 18 .8 21 .2 13 .9 5 13 .7 5 15 .8 16 .4 5 15 .7 15 .8 14 .5 13 .9 5 14 .8 14 .4 5 22 .4 fe 2o 3 3. 01 3. 02 8. 35 7. 66 4 2. 79 6. 85 5. 38 2. 35 7. 23 6. 85 9. 11 8. 66 9. 38 10 1. 98 3. 61 11 .8 10 .9 12 .6 5 11 .6 4. 67 fe o ** * 6. 15 4. 54 n. a. n. a. 8. 93 1. 78 2. 09 2. 10 n. a. 1. 58 n. a. n. a. n. a. n. a. 6. 08 7. 38 n. a. n. a. n. a. n. a. 4. 47 c ao 8. 72 10 .2 12 .1 10 .9 23 7. 72 11 .5 14 .4 5. 96 4. 80 3. 18 7. 6 7. 76 4. 74 7. 09 7. 48 10 .0 10 .1 8. 19 6. 63 10 .3 5 4. 21 m go 5. 46 4. 32 2. 14 1. 83 5 5. 60 5. 64 6. 10 4. 70 4. 28 2. 64 5. 69 6. 58 5. 99 5. 03 6. 28 6. 96 6. 84 6 7. 48 6. 73 4. 37 n a 2o 2. 53 3. 98 3. 21 0 3. 23 3. 77 3. 16 4. 17 7. 47 6. 17 4. 64 5. 04 5. 25 6. 32 5. 57 5. 29 2. 54 3. 33 4. 19 3. 05 3. 29 4. 85 k 2o 0. 51 1 0. 92 9 1. 31 1. 94 4 0. 23 9 <0 .2 <0 .2 0. 26 4 1. 12 3. 56 0. 03 0. 01 <0 .2 0. 05 <0 .2 0. 37 7 0. 17 0. 04 0. 13 0. 16 <0 .2 c r 2o 3 n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. 0. 02 0. 03 n. a. 0. 02 n. a. n. a. 0. 04 0. 03 0. 03 0. 04 n. a. ti o 2 2. 10 2. 00 1. 89 0 2. 02 8 1. 86 0. 64 5 0. 72 8 1. 02 2. 10 1. 37 0. 82 0. 79 0. 82 3 1 0. 82 6 1. 62 1. 66 1. 56 1. 29 1. 58 1. 43 m no 0. 11 2 0. 10 1 0. 10 0 0. 09 6 1. 22 0. 11 8 0. 12 6 0. 08 1 0. 07 7 0. 02 9 0. 16 0. 15 0. 14 5 0. 14 0. 14 6 0. 18 0 0. 18 0. 19 0. 69 0. 18 0. 25 8 p 2o 5 0. 25 8 0. 33 2 0. 36 3 0. 60 8 0. 26 0 <0 .1 5 <0 .1 5 <0 .1 5 0. 29 1 0. 27 5 0. 07 0. 04 <0 .1 5 0. 07 <0 .1 5 <0 .1 5 0. 16 0. 17 0. 1 0. 15 <0 .1 5 sr o 0. 02 6 0. 03 5 0. 02 4 0. 02 4 0. 01 5 0. 02 4 0. 03 3 0. 03 7 0. 07 4 0. 01 6 0. 01 0. 01 0. 01 5 0. 01 0. 01 7 0. 01 3 0. 03 0. 03 0. 01 0. 03 0. 01 7 b ao 0. 00 7 0. 01 1 0. 01 6 0. 01 7 0. 00 6 <0 .0 05 <0 .0 05 0. 00 7 0. 01 6 0. 01 2 0. 01 <0 .0 1 0. 00 6 <0 .0 1 0. 00 8 <0 .0 05 <0 .0 1 0. 01 <0 .0 1 <0 .0 1 <0 .0 05 c n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. 0. 1 0. 04 n. a. 0. 06 n. a. n. a. 0. 01 0. 04 0. 46 0. 02 n. a. s n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. 0. 03 0. 05 n. a. 0. 01 n. a. n. a. 0. 1 0. 02 0. 04 0. 06 n. a. a g n. a. n. a. <0 .2 <0 .2 n. a. n. a. n. a. n. a. <0 .1 n. a. <1 <1 <0 .1 <1 <0 .1 0. 29 <1 <1 <1 <1 n. a. b a 62 .7 98 .5 14 3. 3 15 2. 3 53 .7 <4 4. 8 <4 4. 8 62 .7 14 3. 3 10 7. 5 76 .6 48 .8 53 .7 65 .9 71 .7 <4 4. 8 10 .9 56 .5 70 .8 14 .2 <4 4. 8 c d 0. 11 0 <0 .1 0 <0 .0 6 <0 .0 6 <0 .1 0 0. 27 4 0. 20 1 <0 .1 0 <0 .0 6 <0 .1 0 n. a. n. a. <0 .0 6 n. a. <0 .0 6 <0 .0 6 n. a. n. a. n. a. n. a. 0. 15 3 c e 30 .6 26 .1 37 .4 47 .0 40 .9 5. 71 6. 30 6. 84 27 .0 23 .4 6. 4 6. 8 3. 83 12 .2 4. 91 12 .9 16 15 .4 16 .4 18 .9 10 .5 c o 47 .5 42 .6 36 .7 28 .0 43 .8 44 .5 41 .9 36 .3 49 .4 27 .5 33 .4 36 .5 42 .8 34 41 .2 50 .8 46 .2 40 .4 66 .7 56 .3 36 .8 c r 19 4 18 5 17 2 18 5 26 3 61 8 37 5 50 7 31 1 91 .5 11 0 24 0 15 3 10 0 16 9 23 8 27 0 19 0 22 0 33 0 80 .8 c s 0. 42 6 0. 44 3 1. 20 1. 76 0. 53 1 1. 56 1. 04 0. 79 0 4. 06 7. 27 0. 08 0. 05 <0 .2 5 0. 13 <0 .2 5 0. 47 0. 56 0. 3 1. 5 0. 72 0. 32 8 c u 50 .7 38 .5 20 .2 19 .6 56 .2 47 .0 99 .6 74 .5 40 .8 1. 15 61 44 62 .3 62 62 .6 51 .7 72 41 11 6 92 55 .2 d y 4. 87 4. 32 5. 61 7. 54 5. 50 2. 07 2. 21 2. 62 5. 22 3. 29 3. 85 3. 71 2. 68 4. 25 3. 28 5. 87 7. 3 6. 65 6. 27 8. 46 4. 62 e r 2. 99 2. 81 3. 42 4. 57 3. 46 1. 36 1. 48 1. 93 3. 14 2. 12 2. 42 2. 33 1. 68 2. 67 2. 11 3. 52 4. 56 4. 25 4 5. 34 3. 15 e u 1. 73 1. 51 1. 54 2. 19 2. 20 0. 55 2 0. 60 3 0. 62 0 1. 52 1. 11 0. 81 0. 88 0. 46 1. 04 0. 63 1. 31 1. 63 1. 67 1. 64 2. 01 0. 97 3 g a n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. 15 .6 13 .2 n. a. 19 .3 n. a. n. a. 20 .9 20 .4 22 .8 25 .8 n. a. g d 7. 02 6. 17 5. 39 7. 59 8. 12 2. 37 2. 51 2. 71 4. 79 4. 76 2. 87 2. 91 1. 83 3. 53 2. 32 4. 36 5. 92 5. 26 5. 21 6. 88 5. 07 h f n. a. n. a. 3. 72 4. 23 n. a. n. a. n. a. n. a. <0 .5 n. a. 1. 3 2. 1 <0 .5 5. 3 <0 .5 <0 .5 5. 5 4. 7 3. 7 6 n. a. h o 1. 07 0. 96 1. 16 1. 58 1. 21 0. 45 5 0. 48 2 0. 64 8 1. 17 0. 68 8 0. 81 0. 76 0. 60 0. 92 0. 78 1. 35 1. 53 1. 39 1. 33 1. 88 1. 08 l a 13 .5 11 .0 17 .8 22 .4 12 .2 2. 24 2. 31 2. 41 10 .4 9. 54 2. 3 2. 5 1. 38 4. 6 1. 80 4. 44 5. 4 5. 5 6. 9 6. 2 3. 93 l u 0. 45 5 0. 38 7 0. 42 3 0. 61 2 0. 51 1 <0 .2 5 <0 .2 5 0. 29 4 0. 38 0. 28 7 0. 34 0. 31 0. 25 0. 36 0. 29 0. 50 0. 6 0. 55 0. 54 0. 72 0. 46 8 m o 0. 77 7 0. 88 1 1. 10 1. 28 0. 70 4 <0 .2 5 <0 .2 5 <0 .2 5 <0 .2 0. 21 8 <2 <2 <0 .2 <2 0. 49 5 <0 .2 <2 <2 <2 <2 0. 37 2 n b 12 .0 12 .6 23 .3 25 .1 7. 02 1. 10 1. 28 1. 76 13 .0 5. 19 0. 9 1. 4 <0 .2 5 2. 1 <0 .2 5 1. 75 3. 5 3. 2 2. 8 4 2. 98 n d 19 .1 17 .3 19 .0 26 .8 23 .5 4. 29 4. 85 5. 73 18 .0 15 .6 5. 6 6 3. 72 8. 4 4. 93 11 .1 13 .7 13 .1 12 .5 16 .7 9. 65 n i 11 1 11 2 75 .5 64 .3 76 .1 38 7 24 0 21 1 14 3 46 .1 37 83 54 .4 47 60 .4 64 .7 69 61 29 2 95 44 .7 pb 0. 54 <0 .2 5 <0 .6 <0 .6 4. 55 <0 .2 5 <0 .2 5 <0 .2 5 <0 .6 6. 19 <5 <5 <0 .6 <5 <0 .6 <0 .6 n. a. n. a. n. a. n. a. 1. 74 pr 4. 29 3. 63 4. 77 6. 51 5. 28 0. 87 8 0. 99 1 1. 16 3. 90 3. 53 n. a. 1. 06 0. 63 1. 69 0. 86 2. 11 2. 61 2. 45 2. 39 3. 11 1. 82 r b 7. 30 12 .4 26 .9 36 .0 3. 54 0. 85 1. 46 2. 31 28 .1 10 7 0. 7 0. 6 <0 .2 5 0. 8 <0 .2 5 5. 89 4. 8 1. 1 4. 4 5. 8 1. 05 sm 5. 08 4. 72 4. 59 6. 28 6. 15 1. 42 1. 56 1. 91 4. 96 4. 10 2. 02 2. 07 1. 66 2. 73 1. 83 3. 89 4. 52 4. 01 3. 84 5. 47 3. 45 ta bl e 6. r es ul ts o f t he g eo ch em ic al a na ly se s ( ba sa lt) . kiss et al.: hydrothermal processes related to some triassic and jurassic submarine basaltic complexes in northeastern hungary... 51 d ar nó u ni t sz ar va sk ő u ni t l oc al ity b áj -p at ak n or th q ua rr y h os sz ú va lle y q ua rr y m él y va lle y q ua rr y r es zé l r id ge q ua rr y r m -1 36 dr ill co re e ge rb ak ta q ua rr y r es zé l r id ge n or th , va lle y sz ar va sk ő vi lla ge (n at ur al o ut cr op s) r m -1 36 dr ill co re r oc k ty pe cl os el y pa ck ed pi llo w pe pe ri tic ba sa lt cl os el y pa ck ed pi llo w cl os el y pa ck ed pi llo w cl os el y pa ck ed pi llo w (p ro ve n tr ia ss ic ) ce nt re o f a pi llo w tr an si tio n zo ne o f a pi llo w m ar gi n of a pi llo w pe pe ri tic ba sa lt pr ov en t ri as si c pi llo w ba sa lt cl os el y pa ck ed pi llo w cl os el y pa ck ed pi llo w pe pe ri tic ba sa lt cl os el y pa ck ed pi llo w cl os el y pa ck ed pi llo w cl os el y pa ck ed pi llo w cl os el y pa ck ed pi llo w cl os el y pa ck ed pi llo w cl os el y pa ck ed pi llo w cl os el y pa ck ed pi llo w pr ov en ju ra ss ic pi llo w ba sa lt sn 1. 00 0. 53 7 3. 71 2. 39 3. 24 <0 .5 <0 .5 <0 .5 3. 74 <0 .5 n. a. n. a. 4. 76 n. a. 3. 19 4. 16 n. a. n. a. n. a. n. a. 0. 55 7 sr 21 9. 9 29 6. 0 20 2. 9 20 2. 9 12 6. 8 20 2. 9 27 9. 0 31 2. 9 62 5. 7 13 5. 3 12 5 87 .2 12 6. 8 13 0. 5 14 3. 8 10 9. 9 31 9 29 3 18 2 39 1 14 3. 8 ta 0. 93 8 0. 99 3 5. 97 6. 28 0. 58 0 <0 .2 5 <0 .2 5 0. 13 3 1. 20 0. 38 4 0. 1 0. 1 <0 .2 5 0. 1 <0 .2 5 <0 .2 5 0. 2 0. 2 0. 2 0. 3 <0 .2 5 t b 0. 88 8 0. 78 9 0. 91 1. 28 0. 99 8 0. 35 9 0. 35 7 0. 40 3 0. 85 0. 57 6 0. 57 0. 55 0. 36 0. 62 0. 44 0. 91 1. 1 0. 99 0. 97 1. 29 0. 74 2 t h 1. 29 1. 24 1. 77 1. 89 0. 65 2 0. 42 <0 .2 5 <0 .2 5 3. 48 3. 52 0. 36 0. 3 2. 62 n. a. 2. 63 2. 61 0. 39 0. 44 0. 31 0. 46 0. 30 t l <0 .1 0 <0 .1 0 0. 10 6 0. 16 8 <0 .1 0 <0 .1 0 <0 .1 0 <0 .1 0 <0 .1 0. 42 0 <0 .5 <0 .5 <0 .1 <0 .5 <0 .1 <0 .1 <0 .5 <0 .5 <0 .5 <0 .5 <0 .1 0 t m 0. 47 5 0. 42 9 0. 46 2 0. 67 9 0. 56 5 0. 22 6 0. 25 1 0. 30 6 0. 49 0. 32 5 0. 37 0. 31 0. 26 0. 36 0. 33 0. 57 0. 66 0. 6 0. 56 0. 79 0. 51 2 u 0. 37 1 0. 52 5 0. 50 0 0. 50 3 <0 .2 5 <0 .2 5 <0 .2 5 0. 44 5 0. 62 0. 69 6 0. 1 0. 06 0. 42 0. 16 <0 .2 5 <0 .2 5 0. 14 0. 14 0. 09 0. 14 <0 .2 5 v 31 7 30 3 19 9 19 4 36 7 16 4 14 8 12 6 n. a. 14 7 25 6 23 0 n. a. 29 2 n. a. n. a. 34 9 33 5 30 0 43 3 33 7 w <0 .2 5 <0 .2 5 <0 .2 5 <0 .2 5 0. 64 <0 .2 5 <0 .2 5 <0 .2 5 0. 85 <0 .2 5 <1 n. a. 0. 90 n. a. 0. 87 0. 81 n. a. n. a. n. a. n. a. 0. 72 y 27 .6 24 .7 26 .6 36 .5 32 .7 12 .5 13 .0 16 .0 27 .2 17 .8 20 20 .8 13 .5 23 .4 18 .1 30 .9 40 .2 37 .1 35 .4 48 .8 27 .5 y b 2. 61 2. 38 3. 16 4. 06 3. 15 1. 25 1. 38 1. 77 2. 79 1. 78 2. 33 2. 21 1. 67 2. 52 2. 11 3. 47 4. 3 3. 86 3. 69 5. 01 2. 89 z n 81 .8 68 .7 85 .6 70 .4 98 .2 58 .1 72 .2 38 .9 68 .3 78 .8 70 64 65 .1 90 66 .5 92 .5 10 9 95 12 0 13 5 86 .7 z r 16 1 15 7 12 9 13 6 14 0 42 .0 49 .1 69 .8 13 0 10 8 45 72 39 .3 21 5 38 .1 97 .0 21 2 17 8 13 3 23 2 94 .2 a s n. a. n. a. 8. 48 9. 11 n. a. n. a. n. a. n. a. 4. 28 n. a. 3. 5 2. 4 62 .1 0. 9 2. 88 <0 .6 0. 2 0. 2 2. 8 0. 1 n. a. b i <0 .2 5 <0 .2 5 <0 .2 5 <0 .2 5 <0 .2 5 <0 .2 5 <0 .2 5 <0 .2 5 <0 .2 5 <0 .2 5 0. 05 0. 01 <0 .2 5 0. 04 <0 .2 5 <0 .2 5 0. 03 0. 01 0. 01 0. 01 <0 .2 5 h g n. a. n. a. 0. 00 4 0. 00 2 n. a. n. a. n. a. n. a. 0. 01 5 n. a. 0. 02 8 0. 00 8 0. 00 9 0. 01 6 0. 00 8 0. 00 8 0. 00 8 0. 01 2 0. 02 0. 01 1 n. a. sb 0. 66 1 <0 .1 0 <1 <1 0. 65 8 0. 49 1 0. 26 6 0. 23 1 1. 39 1. 87 0. 06 <0 .0 5 6. 95 <0 .0 5 2. 50 4. 73 <0 .0 5 0. 07 0. 19 <0 .0 5 0. 23 9 se n. a. n. a. <0 .6 <0 .6 n. a. n. a. n. a. n. a. <0 .6 n. a. 0. 6 0. 6 6. 06 0. 8 <0 .6 <0 .6 0. 8 0. 8 0. 8 0. 6 n. a. te n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. 0. 02 <0 .0 1 n. a. <0 .0 1 n. a. n. a. 0. 01 <0 .0 1 <0 .0 1 <0 .0 1 n. a. a u n. a. n. a. <0 .0 02 <0 .0 02 n. a. n. a. n. a. n. a. <0 .0 02 n. a. 0. 00 3 <0 .0 01 <0 .0 02 0. 00 6 <0 .0 02 <0 .0 02 0. 00 8 0. 00 1 <0 .0 01 <0 .0 01 n. a. pt n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. <0 .0 2 <0 .0 05 n. a. <0 .0 2 n. a. n. a. 0. 06 <0 .0 2 <0 .0 05 <0 .0 05 n. a. pd n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. <0 .0 2 0. 00 1 n. a. <0 .0 2 n. a. n. a. 0. 07 <0 .0 2 0. 00 1 <0 .0 01 n. a. o s n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. <0 .0 1 n. a. n. a. <0 .0 1 n. a. n. a. <0 .0 1 <0 .0 1 n. a. n. a. n. a. r u n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. <0 .0 5 n. a. n. a. <0 .0 5 n. a. n. a. <0 .0 5 <0 .0 5 n. a. n. a. n. a. ir n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. <0 .0 01 n. a. n. a. <0 .0 01 n. a. n. a. 0. 00 1 <0 .0 01 n. a. n. a. n. a. r h n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. <0 .0 05 n. a. n. a. <0 .0 05 n. a. n. a. <0 .0 05 <0 .0 05 n. a. n. a. n. a. _h 2o 0. 88 1. 52 0. 15 0. 19 0. 38 0. 69 0. 61 0. 25 n. a. 0. 78 n. a. n. a. n. a. n. a. 0. 27 0. 25 n. a. n. a. n. a. n. a. 0. 76 +h 2o 5. 44 3. 77 3. 96 4. 52 5. 66 4. 21 4. 09 3. 10 n. a. 4. 07 n. a. n. a. n. a. n. a. 3. 30 3. 00 n. a. n. a. n. a. n. a. 3. 82 c o 2 2. 45 7. 73 4. 07 2. 29 3. 72 8. 59 11 .1 4. 15 n. a. 1. 92 n. a. n. a. n. a. n. a. 0. 21 4 <0 .0 2 n. a. n. a. n. a. n. a. 1. 15 l o i n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. n. a. 3. 13 3. 05 n. a. 3. 42 n. a. n. a. 2. 24 3. 22 5. 68 2. 32 n. a. z r/ y 5. 8 6. 4 4. 8 3. 7 4. 3 3. 4 3. 8 4. 4 4. 8 6. 1 2. 3 3. 5 2. 9 9. 2 2. 1 3. 1 5. 3 4. 8 3. 8 4. 8 3. 4 l a/ sm 2. 7 2. 3 3. 9 3. 6 2. 0 1. 6 1. 5 1. 3 2. 1 2. 3 1. 1 1. 2 0. 8 1. 7 1. 0 1. 1 1. 2 1. 4 1. 8 1. 1 1. 1 r es ul ts o f m aj or e le m en t a na ly se s a re g iv en in o xi de % , w hi le m in or a nd tr ac e el em en ts a re g iv en in p pm . *: t he m ea su re m en ts w er e do ne in th e la bo ra to ry o f t he h un ga ria n g eo lo gi ca l i ns tit ut e. ** : t he m ea su re m en ts w er e do ne in th e la bo ra to ry o f t he a ls l ab or at or y g ro up . ** *: w he re f eo is n ot g iv en , t he re th e to ta l f e is g iv en in f e 2o 3. n. a. : n ot a va ila bl e ta bl e 6. r es ul ts o f t he g eo ch em ic al a na ly se s ( ba sa lt) . vol. 69/1 52 darnó unit locality báj-patak n q. reszél ridge q. rock type red limestone (peperitic facies) red limestone (peperitic facies) sample 1* 1* sio2 26.7 7.64 al2o3 5.08 5.17 fe2o3 29.5 43.2 feo** 5.85 n.a. cao 13.7 22.5 mgo 3.22 1.05 na2o 0.230 0.564 k2o <0.2 <0.2 tio2 0.093 0.124 mno 0.116 0.085 p2o5 0.277 0.317 sro 0.006 0.014 bao <0.005 0.005 ag n.a. <0.25 ba <44.8 44.8 cd 0.244 <0.06 ce 6.13 5.17 co 8.48 22.0 cr 14.5 7.29 cs 1.61 <0.625 cu 6.10 <0.2 dy 0.91 0.59 er 0.55 0.34 eu 0.365 0.13 gd 1.27 0.56 hf n.a. <1.25 ho 0.188 <0.125 la 4.10 2.89 lu <0.25 <0.125 mo 1.60 <0.2 darnó unit locality báj-patak n q. reszél ridge q. rock type red limestone (peperitic facies) red limestone (peperitic facies) nb 0.203 <0.625 nd 3.42 3.34 ni 62.8 136 pb <0.25 14.3 pr 0.761 0.80 rb 0.81 <0.625 sm 0.824 0.73 sn <0.5 3.61 sr 50.7 118.4 ta <0.25 <0.625 tb 0.144 <0.125 th <0.25 2.63 tl <0.10 <0.25 tm <0.10 <0.125 u 0.545 <0.625 v 281 n.a. w <0.25 0.88 y 6.27 2.74 yb 0.45 0.28 zn 54.6 71.0 zr 10.3 11.3 as n.a. 17.5 bi <0.25 <0.625 hg n.a. 0.012 sb 0.412 13.5 se n.a. 2.38 au n.a. <0.002 _h2o 0.85 n.a. +h2o 3.04 n.a. co2 11.1 n.a. table 7. results of the geochemical analyses (limestone). analyses of the major elements are given in oxide%, while minor and trace elements are given in ppm. *: the measurements were undertaken in the laboratory of the hungarian geological institute. **: where feo is not given, the total amount of fe is given as fe2o3. n.a.: not available 5. discussion temporal evolution of fluid-rock interactions the submarine basaltic rocks of triassic and jurassic ages from localities in this study area were not formed in a typical mid-oceanic ridge setting (aigner-torres & koller, 1999, balla et al., 1980, buda & kiss, 1980, csontos, 2000, ko vács et al., 2008, 2010, kiss et al., 2008, 2010, 2011, 2012), thus, widely used models for hydrothermal fluid circulation in ophiolitic sequences of oceanic ridges (see e.g. foustoukos & seyfried, 2007, pirajno, 2009, bodnar et al., 2014 and references therein) can not be applied to their hydrothermal systems. the triassic and jurassic basalts studied here were affected by hydrothermal alteration on slightly different scales. hydrothermal alteration minerals are more abundant in the triassic than the jurassic localities, but all occurrences can be categorised into three main groups, according to the model of hart (1973); (1) primary hydrothermal alteration, (2) cooling related hydrothermal alteration and (3) low-temperature hydrothermal alteration. this classification is followed in the discussion below. using this scheme for evaluation of all the available data, the characteristics of the single processes and the importance of the medium (i.e. seawater or unconsolidated sediment) can also be determined. primary hydrothermal alteration primary alteration is present at each studied locality, represented by albititisation of rock forming plagioclase. this took place imkiss et al.: hydrothermal processes related to some triassic and jurassic submarine basaltic complexes in northeastern hungary... 53 figure 3. classification diagrams based on the results of the sem-eds analyses. the composition of the studied plagioclase (a) and pyroxene (b) grains are shown. figure 4. results of the epma elemental mapping in a single thin section. plagioclase laths contain more na and less ca at the margin of the pillows (a-c), than ca. 1.5 cm closer to the middle (d-f) and ca. 3 cm closer to the middle (g-i). the section is from a triassic basalt (rm-131 drillcore, darnó unit, hungary). mediately after solidification of the submarine basaltic flows, as albitisation characterises both the groundmass plagioclase and the porphyric plagioclase. this process could occur around 300°c, according to hart (1973). cooling related hydrothermal alteration the textural characteristics of the basalt (sphaerolitic, variolitic or intersertal texture; skeletal crystal plagioclase, high amount of glassy/microcrystalline material) as well as the composition of the clinopyroxene (high ca, al and fe content, nisbet & pearce, 1977) suggest a very rapid cooling of the basaltic lava. this together with the known geotectonic position (i.e. the absence of a deep-seated long-lasting heatsource), have obvious effects on the possibilities of the fluid/ rock interaction. thus, only very rapid, cooling related hydrothermal processes took place and protracted fluid convection vol. 69/1 54 did not develop. however, some difference between the triassic and the jurassic localities can be observed, as signs of rapid cooling are less dominant in the jurassic basalts (intersertal textures with smaller amounts of microcrystalline material are more common). chloritisation of the ground mass and the formation of the different hydrothermal mineral infillings (cooling cracks, amygdales, mineral band of the pyjamas-type pillow, matrix of the hyaloclastite breccia) have taken place during this cooling related alteration. although the mineral paragenesis may be similar to that figure 5. results of the fluid inclusion study obtained from triassic amygdale filling calcite. figure 6. results of the fluid inclusion study obtained from the calcite of the mineral bands of triassic pyjamas-type pillow. kiss et al.: hydrothermal processes related to some triassic and jurassic submarine basaltic complexes in northeastern hungary... 55 usually connected to low-grade alpine metamorphism, the obvious textural features (e.g. the cooling cracks do not cross-cut the pillow boundaries) and also the observed fluid characteristics (t, x, see e.g. in kiss et al., 2011) help to distinguish different steps of the submarine hydrothermal process from the later low-grade metamorphic overprint (figs. 11-15). however, the cooling-related mineral paragenesis is slightly different in the triassic and jurassic basalts at the studied localities. the triassic basalts are generally characterised by chlorite with some quartz and prehnite in the early high temperature alteration stage, and abundant calcite, together with rare epidote, prehnite, zeolite and pumpellyte formation at the lowest temperatures. in contrast, the jurassic localities are abundant in the high temperature products of chlorite, quartz and prehnite, and only a low amount of lower temperature calcite and pumpellyite occur (figs. 11-15). on the basis of chlorite thermometry (table 5), chloritisation of the ground mass, pseudomorph formation after olivine, as well as formation of some thin, cooling related veinlets, took place at around 180-280°c. this kind of chlorite is associated with some calcite, quartz, prehnite, pumpellyite and epidote, and their formation was the earliest step of the cooling-related processes. infilling of the smaller and larger amygdales in the triassic basalts and some thin veins in both basalts, together with the onset of mineral precipitation in the matrix of the interpillow and pillow fragmented hyaloclastite breccia, collectively represent the next step of the cooling-related fluid/rock interactions. temperatures around 200 °c are characteristic for the small, chlorite or chloritequartz filled amygdales, for precipitation of chlorite along the walls of larger amygdales and in thin veins, as well as for the figure 7.: results of the fluid inclusion study obtained from triassic jig-saw vein filling calcite. figure 8. results of the fluid inclusion study obtained from the calcite of the matrix of triassic hyaloclastite breccias. vol. 69/1 56 earliest precipitation of chlorite grains in the matrix of hyaloclastite breccias (table 5). the fluid inclusion study revealed that the homogenisation temperatures and salinity values are similar to those from the calcite-filled amygdales, pyjama-type pillows and jig-saw veins of some other darnó hill locations, and others at vareš and the stragopetra mts. (kiss et al., 2012). combining all the data presented in kiss et al. (2012) and here (figs. 5-8, table 4), suggests that the lowest temperature stages of the cooling-related fluid/rock interactions can be related to precipitation of calcite in the amygdales, jig-saw veins, former feeding channels, mineral bands of the pyjama-type pillows and in the cement of the hyaloclastite breccia. as the homogenisation temperature corresponds to the minimum formation temperature in the case of the homogenous state of the parent fluid, the exact formation temperatures can be calculated if the pressure conditions of the entrapment of the inclusions are known. in these submarine systems, the pressure is determined by the depth of the seawater. for the triassic localities, 1.5 km water depth is proven at vareš-smreka from a combination of chlorite thermometry and fluid inclusion data (kiss et al., 2012), while a maximum of 4 km depth is assumed for the darnó area (balla et al., 1980). those pressures result in around 10-20 °c correction of the homogenisation temperatures. howe ver, in the case of the jurassic localities, deeper water (~4-6 km) is indicated by the combination of chlorite thermometry with fluid inclusion data (kiss et al., 2011), resulting in a 20-28 °c correction of the homogenisation temperature data. applying this correction to the triassic basalts, the highest temperature conditions for precipitation of calcite existed in the amygdales (~100-180 °c), whereas the lowest temperature conditions characterised the jig-saw veins (~70-140 °c) and the feeding channel and pyjamatype pillow infillings as well as from the hyaloclastite breccia matrix (~80-150 °c) (figs. 11-14). the rather wide range (together figure 9. results of the geochemical analyses. a, b: n-morb normalised trace element spider diagram of the triassic (a) and jurassic (b) basalts. c, d: chondrite normalised ree spider diagram of the triassic (c) and jurassic (d) basalts, note the clear difference observable between them. e: discrimination diagram of pearce & cann (1973), showing different fields of origin for the triassic and jurassic localities. f: discrimination diagram of meschede (1986), showing different fields of origin for triassic (mostly withinplate basalt) and jurassic (mostly islandarc and n-morb) localities. kiss et al.: hydrothermal processes related to some triassic and jurassic submarine basaltic complexes in northeastern hungary... 57 with the significantly lower temperature, in relation to the chlorite formation temperatures) can result from very rapid cooling, i.e. a significant difference can be observed from the margin to the centre of a single amygdale or vein. in contrast, the formation temperature range of the cooling crack calcite in the jurassic basalt is narrower at approx. 130-170 °c (kiss et al., 2011). another important characteristic parameter of the processes is the salinity of the parent fluid (see figs. 5-8 and table 4). for the triassic samples, the fluid inclusion salinities were 3.3-5.6 nacl equiv. wt%, which is around, and just a bit higher, than seawater salinity. the slightly higher salinities may be caused by the effect of the fluid-rock interactions on the composition of upheated seawater (nehlig, 1991). this process is a good explanation for the salinity increase in the thin veins, or amygdales (especially along their walls), where the effective local water/rock ratio is lower. however, it also explains the fact that in the case of the different hyaloclastite breccias (where the local water/rock ratio is obviously higher), the salinity is always similar to the seawater value (fig. 16). in contrast, the results of the thin cooling cracks found in the jurassic basalts correspond to 4.95-9.07 nacl equiv. wt% (kiss et al., 2011), thus a lower water/rock ratio is expected (nehlig, 1991), which may explain (together with the observed higher formation temperatures) the slightly different mineral paragenesis. the results of our studies can be compared with the characte ristics of the hydrothermal system at hruškovec, where a complete submarine volcanic lava flow is known (see above, palinkaš et al., 2008). there, a maximum of 150 °c as homogenisation temperature and seawater salinity is characteristic of the relatively distal facies in relation to the eruptive centre, while up to 250 °c homogenisation temperature, boiling of fluids and up to 23 nacl equiv. wt% salinities (which may be caused by boiling of the modified seawater, see e.g. pirajno, 2009 and bodnar et al., 2014) are typical in the central zones of the lava flow (borojević et al., 2000, borojević pers. comm.). therefore, the fluid inclusion data fully supports the results of the volcanic facies analysis of kiss et al. (2008, 2010, 2012), i.e. the presence of only distal facies at the presently studied, strongly tectonised localities. figure 10. results of the mass transfer calculations. gains and losses of mass of major elements within a single pillow, from core to rim (a), from more central to more distal parts of the same closely packed pillow facies (b), between the closely packed and peperitic pillow facies (c), between the closely packed pillow ad pillow fragmented hyaloclastite breccia facies (d) and gains and losses of mass of trace elements (e). abbreviations: bpé: báj-patak quarry, rt: reszél-tető quarry, hv: hosszú valley quarry, nr: nagy-rézoldal quarry, cl. packed: closely packed pillow facies, hyal. br. fac.: pillow fragmented hyaloclastite breccia facies. vol. 69/1 58 the low temperature hydrothermal alteration the low temperature hydrothermal alteration in the submarine basaltic mounds is the result of the long-lasting seawater-rock interaction at temperatures below 70 °c. according to hart (1973), formation of k-rich smectites is characteristic of this low temperature process. studies by pichler et al. (1999), alt & teagle (2003) and schramm et al. (2005) also confirmed this together with occurrences of celadonite, saponite, iron oxy-hydroxides and rarely, illite-smectite and chloritesmectite interlayered clay minerals. iron oxy-hydroxides occur at all localities studied, but it cannot be stated clearly, whether their occurrence is part of this low temperature alteration process, or to later processes (e.g. to weathering). however, the presence of abundant phyllosilicates can be related to this low temperature hydrothermal process as chlorite-smectite interlayered clay minerals occur both in the groundmass and in some amygdales of basalt. as well as the presence of chlorite-illite interlayered clay minerals, celadonite and smectite were also detected in the basalt at all the studied localities. figure 11. mineral precipitation sequence according to the volcanic facies at the darnó unit, hungary. figure 12. mineral precipitation sequence according to the volcanic facies at the kalnik mts., croatia. kiss et al.: hydrothermal processes related to some triassic and jurassic submarine basaltic complexes in northeastern hungary... 59 geochemical features of fluid/rock interaction as shown in the previous studies, the major and trace element characteristics of basaltic rocks from the studied localities support a different origin for the triassic and jurassic basalts; i.e. a rifting related (within-plate basalt) origin for the triassic examples (kiss et al., 2012) and a subduction related origin for the jurassic basalts (kiss et al., 2011). however, submarine hydrothermal processes certainly have strong effects on the geochemical composition of these rocks (see e.g. hart, 1973, wilson, 1989, karamata et al., 2000, etc), especially if the basalt interacted not only with the seawater, but also with the unconsolidated sediment. the latter may have significant effects also, though it has not been previously studied in detail (see e.g. mukherji, 1972). therefore the significant scattering of results for a few elements (e.g. ca, mg, na, k, fe, mn, au, cu, zn, pb, and lile group, fig. 9 a, b) can be explained by the mobility of those elements during hydrothermal processes. traces of component mobilisation using the mtc method, component mobilisation during the submarine hydrothermal processes were quantitatively modelled. although the number of available analyses does not allow generalised conclusions to be drawn, some preliminary interpretations can be made based on observed variations. slightly different mobilisation patterns were seen at different scales (fig. 10 a-d). within a single pillow, from the centre to its margin, or within the closely packed pillow facies from less to more distal parts, the amount of cao decreases, while the amount of na2o increases. both show good correlation with the macroscopically and microscopically observed alteration intensity of the studied samples. a slight increase of k2o is detected only on larger scales, from less to more distal parts of a single facies or between less and more distal facies, in relation to the centre of the lava flow. figure 13. mineral precipitation sequence according to the volcanic facies at vareš, bosnia and herzegovina. figure 14. mineral precipitation sequence according to the volcanic facies at stragopetra mts., greece. vol. 69/1 60 however, a decrease of sio2 was observed in all studied cases. these changes may be explained by the petrographically observed mineral paragenesis modifications, e.g. the albitisation of anorthite during primary hydrothermal alteration (change in na2o and cao content) or the formation of k-rich clay minerals (change in k2o and sio2 content) during low temperature alteration. important conclusions can be drawn regarding the metal content at the studied localities. copper, zinc and cobalt commonly decrease, from the less distal (thus less altered) to the figure 15. mineral precipitation sequence according to the volcanic facies at the szarvaskő unit, hungary. figure 16. schematic model of a submarine lava flow (palinkaš et al., 2008) and the results of the affecting hydrothermal processes. kiss et al.: hydrothermal processes related to some triassic and jurassic submarine basaltic complexes in northeastern hungary... 61 more distal (thus more altered) parts of either a single pillow or the volcanic centre (fig. 10 e). tracing the effects of the different steps of the hydrothermal processes was possible at several scales from a single pillow to an outcrop, raising the question of whether these phenomena are also present at microscopic (thin section) scale. the epma elemental mapping revealed, that at such a scale, the plagioclase crystals contain more na and less ca closer to the margins of the pillows (sphaerolitic-variolitic texture), than in their inner parts (variolitic-intersertal texture), thus the relative enrichment of na and depletion of ca in the more altered parts is obvious (fig. 4). the geochemical effects of the interaction with the unconsolidated sediment the slight differences in the hydrothermal mineral parageneses (i.e. higher amount of infilling hydrothermal minerals and also, more mineral species, see figs. 11-15) draw attention to the observation of the effects of unconsolidated sediment on the elemental compositon of the basalt. based on the preliminary mtc calculations, more intensive component mobilisation can be recognised in the peperitic facies compared to other facies (see the greater amounts of gains/losses of mass on fig. 10 c). hence the geochemical analyses support the earlier petrographical assumption, i.e. the presence of water saturated, unconsolidated sediment strengthens the effect of hydrothermal alteration in the basaltic rocks. however, it was found that the limestone in the peperitic facies is enriched in co, zn, ti and ni, in relation to a typical limestone (fig. 17, levinson, 1974). thus, where lime mud was present during the submarine hydrothermal processes, the metals escaping from the basalt did not (or not only) dissolve in the seawater, but were also captured in the sediment. determination of the water/rock ratio although at the submarine basaltic eruption centres ‘unlimited’ amounts of seawater is available for the fluid/rock interaction processes, obviously the amount of water taking part effectively in the hydrothermal processes is lower, mostly depending on the available interaction surface. the study of the mineral paragenesis, as well as results of the fluid inclusion study have drawn attention to the importance of this local water/rock ratio (see above). using the numerical results of the mtc calculations and the method described by shikazono et al. (1995), this effective water/rock ratio can be approximated. the results of the calculations support the earlier interpretations; at the closely packed pillow facies of the studied triassic localities a higher water/rock ratio (1520) occurred, while at the studied jurassic localities a lower ratio was obtained (5-10). this fact also supports the conclusion, that this local, effective water/rock ratio is a determining factor in these kinds of submarine hydrothermal systems. the general peculiarities of the hydrothermal process the observed main phases of the fluid/rock interaction processes, as well as the general features of mineral precipitation and the chemical changes are rather similar at both triassic and jurassic localities. in both cases the development of a small scale, rapidly cooling, and slightly modified/evolved seawater dominated system can be reconstructed. this is different from the typically large scale fluid circulation systems of the mid-oceanic ridges (see e.g. nehlig, 1991, foustoukos & seyfried, 2007, pirajno, 2009, bodnar et al., 2014 and references therein). in addition to the main peculiarities listed above, other evidence can also be collected, including the absence of high temperature fluids, differences in the fluid composition properties and the lack of sulfate and sulfide phases. the clear difference from the large scale submarine hydrothermal systems also seems to be obvious in other rifting related submarine basaltic-sedimentary successions e.g. the low temperature, seawater dominated hydrothermal processes in the mecsek mts., southern hungary (jáger et al., 2012). the observed slight, but important differences in the studied small-scale hydrothermal systems are also obvious. however, these differences in the texture, hydrothermal alteration mineralogy and fluid properties can be connected to the different position of the studied blocks in relation to the centre of the lava flow (i.e. different volcanic facies), particularly and practically by the different local, effective water/rock ratio (fig. 16). therefore, we conclude, that the features of the hydrothermal processes are typical to the volcanic facies and vice versa the observed characteristics may help in the spatial reconstruction of the original lava flow. the distinction between the volcanogenic massive sulfide deposit forming i.e. large scale, and the non-extended, i.e. small scale hydrothermal systems is also economically crucial, as the latter does not tend to contain significant ore deposits. the afore-mentioned characteristics may help in distinguishing these different types of ore-productive and barren hydrothermal processes. 6. conclusions submarine hydrothermal alteration of triassic, advanced rifting related pillow basalt at different localities from the dinarides, as well as from displaced fragments of the dinarides and the hellenides were compared with the alteration of jurassic, back-arc/marginal-basin opening related pillow basalt series. the study aimed to complete the earlier less detailed knowledge on the general characteristics of the non-extended, submarine basaltic complex related hydrothermal systems. the study revealed that the most important determining factors of these small scale hydrothermal systems are the extremely rapid cooling of the hydrothermal fluid, the dominance figure 17. selected trace element spider diagram of the studied peperitic limestones, showing enrichment in relation to typical limestones (levinson, 1974). vol. 69/1 62 of the slightly modified seawater as a hydrothermal fluid and the dependence on the local, effective water/rock ratio (i.e. distal/proximal position within the lava flow). the observed features are typical of the volcanic facies, thus may also help in the identification of the spatial relationships within a submarine lava flow. the overall characteristics of these local, submarine basaltic volcanic centre related hydrothermal systems are markedly distinct from the typical mid-oceanic ridge or back-arc-basin opening related, volcanogenic massive sulfide deposit forming large scale hydrothermal systems (see e.g. nehlig, 1991, foustoukos & seyfried, 2007, pirajno, 2009 and bodnar et al., 2014 and references therein). three main phases of submarine hydrothermal processes were distinguished and characterised: the primary hydrothermal processes, which took place at around 300 °c and caused the albitisation of the plagioclase; the hydrothermal alteration processes, during cooling from 300 °c to ~50-70 °c, resulting in the formation of the groundmass chlorite and all the other vein, cavity and amygdale filling hydrothermal minerals; and the low temperature hydrothermal processes below ~50-70 °c, resulting in formation of argillic alteration and iron oxy-hydroxides. based on detailed observation of the textural features and the use of different geothermometry methods, more steps can be distinguished within the cooling related phase of the fluid/rock interaction process. firstly the groundmass alteration product chlorite and the infilling minerals of the thin veinlets formed, which were followed by precipitation of the small and later the bigger amygdale infilling minerals. later still, the infillings of the former feeding channel, and the mineral banding of the pyjama-type pillows precipitated, which was followed by the formation and filling of the jig-saw veins. at the highest temperatures (300-150 °c) mostly chlorite, quartz and prehnite formed, while calcite, laumontite and pumpellyite are more common at lower temperatures (150-70 °c). thus, at those localities, where the higher temperature phases were longer lasting (e.g. the studied jurassic ones), minerals from the first group are dominant, while in the other localities, characterised by dominantly lower temperatures (e.g. the studied triassic localities), minerals from the latter group are more typical. component mobilisation during the different major phases and smaller steps of the hydrothermal processes were also traced. based on the epma elemental mapping and mass transfer calculations, the gains and losses of mass during the fluid/rock interaction were followed at different scales (from microscopic to outcrop scale). the water-saturated sediment of the peperitic facies has strengthened the alteration efficiency of the hydrothermal processes. during the progressive alteration, the amount of cu, zn and co decreased, thus these metals dissolved into the seawater, but in the peperitic facies, they were also captured in the limestone. acknowledgment federica zaccarini (university of leoben, austria), peter jones (carleton university, ottawa, canada) and zsolt bendő (eötvös loránd university, budapest, hungary) are thanked for their assistance with the epma and sem-eds analyses. the university centre for applied geosciences (university of leoben) is thanked for the access to the eugen f. stumpfl electron microprobe laboratory. todor serafimovski (university “goce delčev”-štip, macedonia) and an anonymous reviewer are thanked for their constructive comments, improving the original version of the manuscript. this work was supported by the hungarian-croatian science and technology agreement project no. 07/cro to f. molnár and l. a. palinkaš, by the otka (hnsf) research grant no. t 49633 to f. molnár and by the aöu research grant no. 85öu11 to g. b. kiss and f. zaccarini. references aigner-torres, m. & koller, f. (1999): nature of the magma source of the szarvaskő complex (ne-hungary).– ofioliti, 24, 1–12. alt, j.c. & teagle, d.a.h. (2003): hydrothermal alteration of upper oceanic crust formed at a fast-spreading ridge: mineral, chemical, and isotopic evidence from odp site 801.– chem. geol., 201, 191–211. árkai, p (1983): very lowand low-grade alpine regional metamorphism of the paleozoic and mesozoic formations of the bükkium, ne hungary.– acta geol. hung., 26, 83–101. árkai, p (2001): alpine regional metamorphism in the main tectonic units of hungary: a review.– acta geol. hung., 44/2–3, 329–344. árkai, p., balogh, k. & dunkl, i. (1995): timing of low-temperature metamorphism and cooling of the paleozoic and mesozoic formations of the bükkium, innermost western carpathians, hungary.– geologische rundschau, 84/2, 334–344. árváné sós e., balogh k., ravaszné baranyai l. & ravasz cs. (1987): mezozoós magmás kőzetek k/ar kora magyarország egyes területein (k/ar age of mesozoic magmatic rock sin hungary).– máfi évi jelentése az 1985. évről, 295-307 (in hungarian). balla, z. (1984): the north hungarian mesozoic mafics and ultramafics.– acta geol. hung., 27, 341–357. balla, z. (1987): a bükk-hegység mezozoós tektonikája és kapcsolata a nyugati-kárpátokkal és a dinaridákkal (tectonics of the bükkian (north hungary) mesozoic and relations to the west carpathians and dinarides).– ált. földt. sz., 22, 13–54 (in hungarian). balla, z., baksa, cs., földessy, j., havas, l. & szabó, i. (1980): the tectonic setting of the ophiolites in the bükk mountains (north hungary).– geol. carpath., 31/4, 465–493. balogh, k. & pécskay, z. (2001): k/ar and ar/ar geochronological studies in the pannonian-carpathians-dinarides (pancardi) region.– acta geol. hung., 44, 281–299. bodnar, r.j., lecumberri-sanchez, p., moncada, d. & steelemacinnis m. (2014): fluid inclusions in hydrothermal ore deposits.– in: holland, h.d. & turekian, k.k. (eds.): treatise on geochemistry, second edition, oxford: elsevier, 13, 119–142. boynton, w.v. (1984): cosmochemistry of the rare earth elements: meteorite studies.– in: henderson, p. (ed.): rare earth element geochemistry, elsevier, amsterdam, 63–114. borojević, s., palinkaš, l.a. & bermanec, v. (2000): fluid inclusions in pillow lavas of hruškovec, mt. kalnik.– proc. croat. geol. congr., 123–125. brauhart, c.w., huston, d.l., groves, d.i., mikucki, e.j. & gardoll, s.j. (2001): geochemical mass transfer patterns as indicators of the architecture of a complete volcanic-hosted massive sulfide hydrothermal alteration system, panorama district, pilbara, western australia.– econ. geol., 96, 1263–1278. buda, gy. & kiss, j. (1980): comparison some chromite and titaniferous magnetite, ilmenite ore bearing ultrabasic-basic complexes.– unesco int. symp. athens, 1, 21–45. cathelineau, m. & izquierdo, g. (1988): temperature — composition relationships of authigenic micaceous minerals in the los azufres geothermal system.– contrib. to mineral. petrol., 100/4, 418–428. csontos, l. (1995): tertiary tectonic evolution of the intra-carpathian area: a rewiev.– acta vulc., 7/2, 1–13. csontos, l. (1999): a bükk-hegység szerkezetének főbb vonásai (structure of the bükk mts.).–földt. közl., 129/4, 611–651 (in hungarian). csontos, l. (2000): a bükk hegység mezozoós rétegtani újraértékelése (reevaluation of the mesozoic stratigraphy of the bükk mts.).– földt. közl., 130/1, 95–131 (in hungarian). csontos, l. & vörös, a. (2004): mesozoic plate tectonic reconstruction of the carpathian region.– palaeogeogr., palaeoclimat., palaeoecol., 210, 1–56. dimitrijević, m. n., dimitrijević, m. d., karamata, s., sudar, m., gerzina, n., kovács, s., dosztály, l., gulácsi, z., less, gy. & pelikán, p. (2003): olistostrome/mélanges – an overview of the kiss et al.: hydrothermal processes related to some triassic and jurassic submarine basaltic complexes in northeastern hungary... 63 problems and preliminary comparison of such formations in yugoslavia and ne hungary.– slovak. geol. mag., 9/1, 3–21. dosztály, l. & józsa, s. (1992): geochronological evaluation of mesosoic formations of darnó hill at recsk on the basis of radiolarians and k-ar age data.– acta geol. hung., 35/4, 71–393. dosztály, l., gulácsi, z. & kovács, s. (1998): az észak-magyarországi jura képződmények rétegtana (stratigraphy of the n-hungarian jurassic rocks).– in: bérczi, i. & jámbor. á. (ed.): magyarország geológiai képződményeinek rétegtana, 309–318 (in hungarian). downes, h., pantó, gy., árkai, p. & thirlwall, m.f. (1990): petrology and geochemistry of mesozoic igneous rocks, bükk mountains, hungary.– lithos, 24/3, 201–215. foustoukos, d.i. & seyfried, w.e. (2007): fluid phase separation processes in submarine hydrothermal systems.– reviews mineral. geochem., 65, 213–239. grant, j.a. (1986): the isocon diagram—a simple solution to gresens’ equation for metasomatic alteration.– econ. geol., 81, 1976–1982. haas, j. & kovács, s. (2001): the dinaric-alpine connection as seen from hungary.– acta geol. hung., 44/2–3, 345–362. haas, j., kovács, s., pelikán, p., kövér, sz., görög, á., ozsvárt, p., józsa, s. & németh, n. (2011): a neotethys-óceán akkréciós komplexumának maradványai észak-magyarországon (remnants of the neotethyan accretionary complexes in n-hungary).– földt. közl., 141/2, 167– 196 (in hungarian, with english abstract). hall, d.l., sterner, s.m. & bodnar, r.j. (1988): freezing point depression of nacl-kcl-h2o solutions.– econ. geol., 83, 197–202. harangi, sz., szabó, cs., józsa, s., szoldán, zs., árva-sós, e., balla, m. & kubovics, i. (1996): mesozoic igneous suites in hungary: implications for genesis and tectonic settings in the northwestern part of tethys.– int. geol. rev., 38, 336–360. hart, r.a. (1973): a model for chemical exchange in the basalt-seawater system of oceanic layer ii. – can. j. earth. sci., 10, 799–816. hrvatović, h. (2006): geological guidebook through bosnia and herzegovina.– geological survey of federation bosnia and herzegovina, sarajevo, 172 p. jáger, v., molnár, f., buchs, d. & kodera, p. (2012): the connection between iron ore formations and “mud-shrimp” colonizations around sunken wood debris and hydrothermal sediments in a lower cretaceous continental rift basin, mecsek mts., hungary.– earth-sci. rev., 114/3–4, 250–278. jones, g. & robertson, a.h.f. (1991): tectono-stratigraphy and evolution of the pindos ophiolite and associated units.– j. geol. soc. london, 148, 267–268. józsa, s. (1999): a darnó-hegyi óceánaljzati magmás kőzetek petrológiaigeokémiai vizsgálata. – phd dissertation (petrological and geochemical analysis of the submarine igneous rocks of the darnó hill), eötvös loránd university (in hungarian with english abstract). karamata, s., knežević, v. & cvetković, v. (2000): petrology of the triassic basaltoid rocks of vareš (central bosnia).– acta geol. hung., 43/1, 1–14. kiss, g., molnár, f. & palinkaš l.a. (2008): volcanic facies and hydrothermal processes in triassic pillow basalts from the darnó unit, ne hungary.– geol. croat., 61/2–3, 385–394. kiss, g., molnár, f., †kovács, s. & palinkaš, l.a. (2010): field characteristics and petrography of the advanced rifting related triassic submarine basaltic blocks in the jurassic mélange of the darnó unit.– centr. eur. geol., 53/2–3, 181–204. kiss, g., molnár, f., koller, f. & péntek, a. (2011): triassic rifting and jurassic ophiolite-like magmatic rocks in the bükk unit, ne-hungary– an overview.– mitt. österr. mineral. ges., 157, 43–69. kiss, g., molnár, f., palinkaš, l.a., kovács, s. & hrvatović, h. (2012): correlation of triassic advanced rifting related neotethyan submarine basaltic volcanism of the darnó unit (ne hungary) with some dinaridic and hellenidic occurrences on the basis of volcanological, fluid-rock interaction and geochemical characteristics.– int. j. earth. sci., 101/6, 1503–1521. kohút, m. & kiss, g. (2013): plagiogranites from szarvaskő (bükk unit, ne-hungary): a monazite emp dating. occasional papers of the geological and geophysical institute of hungary, 1, 28–29. kovács, s., haas, j., szebényi, g., gulácsi, z., pelikán, p., b.árgyelán, g., józsa, s., görög, á., ozsvárt, p., gecse, zs. & szabó, i. (2008): permo-mesozoic formations of the recsk-darnó hill area: stratigraphy and structure of the pre-tertiary basement of the paleogene recsk orefield.– in: földessy, j. & hartai, é. (ed): recsk and lahóca geology of the paleogene ore complex, geosciences. publications of the university of miskolc, series a, mining, 73, 33–56. †kovács, s., haas, j., ozsvárt, p., palinkaš, l.a., kiss, g., molnár, f., józsa, s. & kövér, sz. (2010): re-evaluation of the mesozoic complexes of darnó hill (ne hungary) and comparisons with neotethyan accretionary complexes of the dinarides and hellenides – preliminary data.– centr. eur. geol., 53/2–3, 205–231. kubovics, i. (1984): on the petrogenesis of the north hungarian basic-ultrabasic magmatic rocks.– acta geol. hung., 27/1–2, 163–189. kranidiotis, p. & maclean, w.h. (1987): systematics of chlorite alteration at the phelps dodge massive sulphide deposit, matagami, quebec.– econ. geol., 82, 1898–1911. levinson, a.a. (1974): introduction to exploration geochemistry: calgary, applied publishing, ltd., 612 p. maclean, w.h. & kranidiotis, p. (1987): immobile elements as monitors of mass transfer in hydrothermal alteration: phelps dodge massive sulfide deposit, matagami, quebec.– econ. geol., 82, 951–962. doi: 10.2113/gsecongeo.82.4.951 meschede, m. (1986): a method of discriminating between different types of mid-ocean ridge basalts and continental tholeiites with the nb-zr-y diagram.– chem. geol., 56, 207–218. molnár, zs., kiss, g.b. & zaccarini, f. (2015): study of an epigenetic copper occurrence at the darnó hill (ne-hungary) and its correlation with some dinaridic and hellenidic occurrences.– carpathian j. earth environment. sci., 10/2, 59–76. morimoto, n. (1989): nomenclature of pyroxenes.– can. mineral., 27, 143– 156. mukherji, s. (1972): interaction of magma and sedimentary rock sin the bükk mountains, hungary.– acta geol. acad. sci. hung., 16, 29–42. naden, j. (1996): calcicbrine; a microsoft excel 5.0 add-in for calculating salinities from microthermometric data in the system nacl-cacl2-h2o.– in: brown, p.e. & hagemann, s.g. (eds.): pacrofi vi, madison , wi. nehlig, p. (1991): salinity of oceanic hydrothermal fluids: a fluid inclusion study.– earth planet. sci. letters, 102, 310–325. doi: 10.1016/0012-821x(91)90026-e nisbet, e.g. & pearce, j.a. (1977): clinopyroxene composition in marie lavas from different tectonic settings.– contrib. miner. petrol., 63, 149– 160. ozsvárt, p., dosztály, l., migiros, g., tselepidis, v. & kovács, s. (2012): new radiolarian biostratigraphic age constraints on middle triassic basalts and radiolarites from the inner hellenides (northern pindos and othrys mountains, northern greece).– int. j. earth sci., 101/6, 1487–1501. palinkaš, a.l., bermanec, v., borojević šoštarić, s., kolar jurkovšek, t., strmić palinkaš, s., molnár, f. & kniewald, g. (2008): volcanic facies analysis of a subaqueous basalt lava-flow complex at hruškovec, nw croatia-evidence of advanced rifting in the tethyan domain.– j. volc. geotherm. res., 178, 644–656. pamić, j. (1984): triassic magmatism of the dinarides in yugoslavia.– tectonophysics, 109/3–4, 273–277. doi: 10.1016/0040-1951(84)90145-8 pamić, j. & tomljenović, b. (1998): basic geological data from the croatian part of the zagorje-mid-transdanubian zone. acta geol. hung., 41/4, 389–400. pearce, j.a. & cann, j.r. (1973): tectonic setting of basic volcanic rocks determined using trace element analyses.– earth planet. sci. letters., 19, 290–300. pelikán, p. (ed.) (2005): a bükk-hegység földtana (geology of the bükk mts.).– magyar állami földtani intézet kiadványa, budapest, 284 p. (in hungarian). péntek, a, molnár, f. & watkinson, d.h. (2006): magmatic fluid segregation and overprinting hydrothermal processes in gabbro pegmatites of the neotethyan ophiolitic szarvaskő complex (bükk mountains, ne hungary).– geol. carpathica., 57/6, 433–446. petrelli, m., poli, g., perugini, d. & peccerillo, a. (2005): petrograph: a new software to visualize, model and present geochemical data in igneous petrology.– geochem., geophys., geosyst., doi: 10.1029/2005gc000932 pichler, t., ridley, w.i. & nelson, e. (1999): low-temperature alteration of dredged volcanics from the southern chile ridge: additional information about early stages of seafloor weathering.– marine geol., 159, 155–177. pirajno, f. (2009): submarine hydrothermal mineral systems.– in: pirajno, f. (ed.): hydrothermal processes and mineral systems, springer, 1250 p. potter, r.w. & clynne, m.a. (1978): solubility of highly soluble salts in aqueous media part i. nacl, kc1, cacl2, na2s04 and k2s04 solubilities to 100°c.– j. res. u. s. geol. survey., 6, 701–705. rassios, a. & moores, e. (2006): heterogeneous mantle complex, crustal processes and obduction kinematics in a unified pindos-vourinos ophiolitic slab (northern greece).– in: robertson, a.h.f. & mountrakis, d. (eds): tectonic development of the eastern mediterranean region. geological society, london, special publications, 260, 237–266. doi: 10.1144/gsl. sp.2006.260.01.11 robertson, a., karamata, s. & saric, k. (2009): overview of ophiolites and related units in the late palaeozoic–early cenozoic magmatic and tectonic development of tethys in the northern part of the balkan region. ophiolites and related geology of the balkan region.– lithos, 108/1, 1–36. sadek ghabrial, d., árkai, p. & nagy, g. (1996): alpine polyphase metamorphism of the ophiolitic szarvaskő complex, bükk mountains, hungary.– acta mineral. petrol., 37, 99–128. vol. 69/1 64 schmid, m.s., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine-carpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss j. geosci., 101/1, 139–183. doi: 10.1007/ s00015-008-1247-3 schramm, b., devey, c.w., gillis, k.m. & lackschewitz, k. (2005): quantitative assessment of chemical and mineralogical changes due to progressive low-temperature alteration of east pacific rise basalts from 0 to 9 ma. chem. geol., 218/3-4, 281–313. shikazono, n., utada, m. & shimizu, m. (1995): mineralogical and geochemical characteristics of hydrothermal alteration of basalt in the kuroko mine area, japan: implications for the evolution of a back arc basin hydrothermal system.– appl. geochem., 10, 621–642. doi: 10.1016/08832927(95)00032-1 skilling, i.p., white, j.d.l. & mcphie, j. (2002): peperite: a review of magma-sediment mingling.– j. volc. geotherm. res., 117, 1–17. doi: 10.1016/s0377-0273(01)00278-5 sun, s.s. (1980): lead isotopic study of young volcanic rocks from mid-ocean ridges, ocean islands and island arcs. philos.– transact. royal soc., a297, 409–445. doi: 10.1098/rsta.1980.0224 sun, s.s. & mcdonough w.f. (1989): chemical and isotopic systematics of oceanic basalts: implications for mantle compositions and processes.– in: norry, m.j. & saunders, a.d. (eds.): magmatism in the ocean basins.– geological society, london, 313–345. doi: 10.1144/gsl. sp.1989.042.01.19 szentpétery, zs. (1953): a déli-bükk-hegység diabáz és gabbrótömegei (the diabase and gabbro bodies of the southern bükk mts.).– magyar állami földtani intézet évkönyve, 41/1, 1–102 (in hungarian). trubelja, f., burgath, k-p. & marchig, v. (2004): triassic magmatism in the area of the central dinarides (bosnia and herzegovina): geochemical resolving of tectonic setting.– geol. croat., 57/2, 159–170. ulrich, t. & heinrich, c.a. (2002): geology and alteration geochemistry of the porphyry cu-au deposit at bajo de la alumbrera, argentina.– econ. geol., 97, 1865–1888. doi: 10.2113/gsecongeo.97.8.1865 wilson, m. (1989): igneous petrogenesis. a global tectonic approach.– harper collins academic, london, 466 p. doi: 10.1007/978-94-010-9388-0 zane, a. & weiss, z. (1998): a procedure for classifying rock-forming chlorites based on microprobe data.– rend. linc. sci. fis. nat., serie 9, 9, 51–56. zang, w. & fyfe, w.s. (1995): chloritization of the hydrothermally altered bedrock at the igarapé bahia gold deposit, carajás, brazil.– mineral. dep., 30, 30–38. zhang, y.g. & frantz, j.d. (1987): determination of homogenization temperatures and densities of supercritical fluids in the system nacl-kcl-cacl2h2o using synthetic fluid inclusions.– chem. geol., 64, 335–350. 2021 | 74/2 | 163–176 | 9 figs. | 3 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction although serbia is a small european country, it has a rich geo­ heritage. there are numerous geological and geomorphological sites, which are excellent representatives of geodiversity. the cur­ rent inventory of eighty protected geoheritage sites includes about 650 geological, hydrogeological, palaeontological, geomorpho­ logical, spelaeological and neotectonic phenomena (djurović & mijović, 2006, vasiljević, 2015). there are numerous geosites with unique diversity, which can provide authentic and unforgettable experiences to tourists. such an environment pos­ sesses an outstanding opportunity regarding geotourism deve­ lopment. devil’s town is an excellent representative of rich natu­ ral heritage and it can potentially represent high geotouristic values being as one of the protected geomorphological geoherita ge sites (stanković, 2004) and the most important geomor­ phological monument of nature in serbia formed by erosion (ristić et al., 2018). concerning major geostructures designated to geodiversity, devil’s town considers “geomorphological oc­ currences, erosion and depositional proccesses and landscapes’’ (djurović & mijović, 2006). the site is classified into the first category of protected sites, i.e. the category of natural mon­ uments of outstanding importance, and has been declared a geo­ logical monument of nature. regarding topography, the area is highly diverse. the occurrence of 202 stony topped earth pillars (french term ‘’demoiselle’’; north american term ‘’hoodoo’’; in­ cluding universal terms: ‘’pedestal rocks’’, ‘’rock pinnacles’’; ‘’earth pinnacles’’, earth pillars’’, ‘’rock pillars’’; earth pyra­ mids) is noteworthy. these are rare natural phenomena resem­ bling very attractive denudation relief forms (gullies are the most dominant forms, including ground­water seepages and scars). assessment of the geotouristic values of devil’s town, serbia danijela vukoičić1, danica srećkovićbatoćanin2, aleksandar valjarević3, dušan ristić1, milena nikolić1 and dragana valjarević4 1 university of priština in kosovska mitrovica, faculty of sciences and mathematics, department of geography, lole ribara 29, 38220 kosovska mitrovica 2 university of belgrade, faculty of mining and geology, đušina 7, 11000 belgrade, serbia 3 university of belgrade, faculty of geography, department of geospatial and environmental science studentski trg 3/iii, 11000 belgrade, serbia 4 university of pristina in kosovska mitrovica, faculty of sciences and mathematics, department of mathematics, lole ribara 29, 38220 kosovska mitrovica (*corresponding author: dragana.valjarevic@pr.ac.rs) doi: 10.4154/gc.2021.11 abstract serbia is a country rich in geoheritage with eighty geomorphological sites now under protection. although a canyon, the site of devil’s town is a unique geomorphological site in serbia and deserves special attention. the geotouristic values of devil’s town were assessed based on the analysis of its present state and comparison with three similar and nearby geosites on the balkan pennisula (the sand pyramids in bosnia and herzegovina and the stob and melnik earth pyramids in bulgaria). the assessment was performed using a ‘modified geosite assessment model’ (m-gam), which includes estimation of the main indicators and sub-indicators. devil’s town has an average level of major and additional values. indicators show that this geosite has great tourist, scientific and aesthetic value, as well as enough space for improving the ecological and functional values, as a basis for the development of tourism. devil’s town displays a higher touristic value than the sand pyramids and slightly lower than the stob pyramids. however, in comparison with the melnik earth pyramids in bulgaria, its touristic value is significantly lower. this study could serve as a guide for managing development strategies concerning decision-making and engagement in tourism of the analysed geosite, addressing the needs of modern tourists. however, the geotourism potential and geoturist values of this geosite remain partially hidden. the promotion of geological and geomorphological heritage is growing in importance when it comes to cultural tourism and landscape valorisation as thematic excursions and itineraries (reynard, 2009). the first official definition of geotourism was given by thomas hose, (1995,1996), and later reformulated (hose, 2000). geotourism, as a geoscience­based tourist activi ty, is a process of recognizing and giving a wider meaning to geoheritage objects in order to preserve them more effectively (hose, 2005a). a straightforward definition was given by joyce (2006), who defines geotourism as a situation where “people go to certain places to observe one or more aspects of geology and geomorphology and learn about them.” the definition of geo­ tourism given by gray (2008), takes a view on the need for geo­ conservation; “tourism is based on geological and geomorpholo­ gical resources of an area that attempts to minimize the (negative) impact of this tourism through geoconservation and sustainable management”. under geoconservation, burek & prosser (2008) include active site management in order to preserve the original state and prevent any changes. geoconservation measures in combination with the promotion of tourism are the most impor­ tant elements of geotourism (hose, 2005b). sadry (2009) states that geotourism is in fact knowledge­based tourism, interdisci­ plinary integration of the tourism industry with conservation and interpretation of the attributes, abiotic in nature, in order to bring the geosite closer to the general public. newsome & dowling (2010) have come to the conclusion that geotourism promotes tourism at geosites as well as the conservation of geodiversity and understanding of the geosciences by means of respect and understanding (learning). the latest definition of modern geo­ article history: manuscript received may 19, 2020 revised manuscript accepted march 22, 2021 available online june 30, 2021 keywords: geotourism, geosite assessment, m-gam, comparative analysis, devil’s town, sand pyramids, stob pyramids, melnik pyramids, serbia g eo lo gi a c ro at ic a 164 geologia croatica 74/2 tourism was developed by hose & vasiljević (2012): “pro­ viding interpretative content and services at geosites, geomor­ phological sites and the surrounding topography, together with related in­situ and ex­situ artifacts, in order to conserve them, improve their appreciation, education and scientific work both [by, and] for, the present and the future generations.” the basic principles of the fundamental importance for geo­ tourism are: geological basis, sustainability, geointerpretation, benefit to the local community and tourist satisfaction (dowl­ ing, 2011). the economic perspective should also be taken into account. geosites as a basis of geotourism development contribu te to both the original and the additional tourist offer (pralong, 2006). in the context of geotourism, geoheritage provides the original offer. the additional offer consists of the infrastructure, goods and services offered to tourists in order to complete, improve and facilitate their visit. these can be informative and interpretative boards, the construction of paths and lifts to hard­ to­reach places, or the organization and training of the guides (pralong & reynard, 2005; reynard, 2008). tourist exploitation of geography can have a negative impact on earth systems (newsome & dowling, 2006; hose, 2008; hose et al., 2011; hose & vasiljević, 2012) which can lead to deg­ radation and an increase in the vulnerability of the geodiversity. thus, it is necessary to create such an offer that will bring geo­ logical and geomorphological knowledge and scientific achieve­ ments to all visitors, as well as enabling the undisturbed and im­ proved development of tourist activities. numerous methods which were used for evaluating geosites were focused on the scientific value of the geosite, and only later included additional values (grandgirard & szepesi, 1997; braga, 2002; bruschi & cendrero, 2005; panizza & piacente, 2003; coratza & giusti, 2005; gray, 2013; pralong, 2005; brilha, 2005; reynard, 2009; rey­ nard et al., 2016; reynard & brilha., 2018; pereira et al., 2007; reis & henriques, 2009; tomić, 2011; vujičić et al., 2011; rocha et al., 2014). evaluation of geodi­ versities and geoheritage in serbia was carried out mainly using a descriptive method until the last decade of the 20th century when eminent experts from all geodisciplines established and proposed scientific and educational criteria for geoheritage evalu­ ation, while planning the protection of natural areas (nojković & mijović, 1998; mijović & miljanović, 1999). in the last few years, a lot of authors from serbia have contributed to the foundation of modern thought on the need and significance of protecting and promoting geodiversity and geoheritage (lješević, 2002; mijović, 2002; mijović et al., 2005; djurović & mijović, 2006; belij, 2007; 2008; 2009; vujičić et al., 2011; vasiljević et al., 2011; tomić, 2011; božić & tomić, 2015; boškov et al., 2015; tomić & božić, 2016; antić & tomić, 2017; valjarević et al., 2017; vukoičić et al., 2018; antić et al., 2019; antić et al., 2020). serbia has the potential for an increase in geotourism but is obviously lagging behind countries with developed tourism. hence, the main goal of this study is to assess the geotouristic values of devil’s town and its comparison with the three simi­ larly featured and nearby geosites in the balkans (sand pyramids in bosnia and herzegovina and stob and melnik earth pyramids in bulgaria) by applying the m­gam model. the results obtained should point to the potential advantages and disadvantages in these analyzed localities as well as to the main future tasks of management during the planning and development of a tourist offer aiming to adjust these to attractive tourist destinations. 2. material and methods 2.1. study area devil’s town spatially belongs to the municipality of kuršumlija, and the village of djake on radan mountain (central part of southern serbia). it covers an area of 8.31 ha, at an altitude of 660 – 796 m a.s.l. the devil’s town is located 290 km from belgrade, figure 1. location map of devil’s town (source of hypsometry: cgiar consortium for spatial information, 2017). g eologia c roatica 165vukoičić et al.: assessment of the geotouristic values of devil’s town, serbia 29 km from kuršumlija, and 9 km from the state road ib category no. 35 niš­priština. beside this state road, there is also the niš ­ prokuplje ­ kosovo polje railway. the closest airports are slatina in priština (57 km) and the airport in niš (92 km). prolom banja, which is one of the most visited spas of great touristic value in serbia (tomić & košić, 2020), is located nearby, 28 km from devil’s town. these two tourist­attractive destinations are con­ nected by a well­built hiking trail. parking for vehicles is 850 m away from devil’s town, and the hiking trail leads to the top of the erosive fountain with a viewpoint that allows sightseeing and photography of the stone formations. at the beginning of the hik­ ing trail, several ethno­style mountain lodges were built, one housing a restaurant with food prepared in the traditional serbian style and an art galery where the photo­contest “devil’s town” is traditionally held in may each year (fig. 1). regarding geology, devil’s town is located within the lece volcanic complex, which is one of the largest tertiary volcanic provinces in serbia. it is, (observing the geotectonic setting), situ­ ated along the boundary between the serbo­macedonian mass (smm) to the east and the eastern vardar zone to the west (fig. 2). these two units are delineated by the propolac–medvedja and tupala dislocation (stajević, 2004). the former unit has been interpreted as part of the deformed margin of the eurasia conti­ nental plate, while the latter is considered a remnant of the vast tethys ocean (e.g. schmid et al., 2008). according to the generally accepted explanation, the volca­ nic complex of lece was formed in response to the dinaride col­ lapse. magmatism took place along dextral strike­slip faults that resulted in transpressive crustal shortening and collision of the smm as a part of the european plate within a short time frame, from about 33 to 31 ma (dragić et al., 2014; tosdal, 2012). the unique geomorphological phenomenon in serbia con­ tains about 202 stone formations formed on steep slopes of two deep, parallel cut gullies. the formations are of different shapes and sizes. the oldest ones are the highest, up to 17 m high, and they are placed at about 670 m a.s.l., while smaller forms are up to 2 m high and are placed at about 680 to 700 m a.s.l. today, it is very easy to find videos of devil’s town on the internet. these specific natural formations are the result of an erosive process that lasted for at least two hundred thousand years, dur­ ing which those formations evolved and passed through different stages of development. the devil’s town rocks are andesitic vol­ canic and volcaniclastic rocks and have been protected since 1959. in 1995, the decree of the government of the republic of serbia proclaimed a site of national importance“ and placed into the highest category of protection. a total area of 67 hectares is protected, although there is a requirement to increase the pro­ tected area to 1014 ha. 2.2. geological background the geology of the broader area is presented on the basic geological map 1:100.000, sheets kuršumlija and podujevo (malešević et al., 1974; vukanović et al., 1975). the old­ est rocks are cambrian gneisses and subordinate devonian meta­ morphosed limestone. broad areas cover cretaceous products, conglomerate and flysch sediments associated with members of the jurassic ophiolite mélange (previously known as the “diabase­ chert formation” dimitrijević & dimitrijević, 1974). the most dominant lithological units are products of oligocene vol­ canism with a formation age of 32–28 ma (karamata et al., 1992; kostić et al., 2017). these volcanic products are andesites and volcaniclastic rocks including lava flows, pyroclastic brec­ cias, crystalline and lapilli tuffs (dimitrijević & drakulić, 1958; dragić et al., 2014). andesite displays a porphyritic tex­ ture, and contains plagioclase (fig.3a), amphibole­hornblende (fig.3b), biotite (less frequently) and monoclinic and orthorhom­ bic pyroxenes as phenocrysts. accessory constituents are apatite and opaque minerals. their uniform chemistry suggests uniform volcanism within the entire complex (jovanović et al., 1972). negligible variations in chemistry could be a consequence of figure 2. geological map of research area. source: map processed by authors based on data of geoliss, 2020). g eo lo gi a c ro at ic a 166 geologia croatica 74/2 minimal changes of steam pressure inside a volcanic vent or in­ ternal diffusion during peaceful phases as well as hydrothermal action and subsequent alteration (jovanović et al., 1972). py­ roclastic rocks, including some well­bonded ignimbritic types, comprise horizons from a few ­ 100 m thick. hydrothermally al­ tered rocks are most abundant in the area of interest occurring as reef zones due to their higher resistance (fig. 3c, d). the most intensive hydrothermal process is silicification revealing the re­ markable, several kilometers long zone of silicification known as the “quartzose­brecciated zones” (pešut, 1976). at higher ele­ vation, intense phyllic alteration occurs, which encompasses the mineralized rocks (dragić et al., 2014). hydrothermal altera­ tion developed along favourable volcanic­tectonic and tectonic rupture systems (stajević, 2004). fissures about 1km in length prevail, although some exceed a few km. in the same fracture zones precious minerals occur together with galena, sphalerite, pyrite and gold (e.g. the rasovača, vrtače, kameno rebro and bučumet deposit). precious silicate minerals include amethyst, amethyst­agate, agate, fibrous chalcedony, granular quartz and relic opal, which display very heterogeneous colour varieties (miladinović et al., 2010). although gemstone deposits be­ came the subject of interest after world war ii, on the basis of certain archaeological finds it is known that the amethyst and ag­ ate had been exploited by the ancient romans. numerous poorly explored occurrences, mostly placer deposits (eluvial, deluvial, proluvial and alluvial), distributed outwith the volcanic complex, i.e. on its eastern rim also exist. volcanic products affected by si­ liceous and/or siliceous­mineralized hydrothermal fluids were later exposed to further weathering and erosion along the already existing fissures. volcanoes in this area undoubtely exceeded 1000 m in height (gajtan caldera in spite erosion and shortenning reaches approxi­ mately 700 m a.s.l.). devil’s town is the largest and most complex caldera with a diameter of about 25 km. the best preserved parts are at sokolovica (in the north) and at markov vis (in the south). 2.3. relief shaping volcanism initially sculpted this area in the palaeogene, i.e. up­ per oligocene (dimitrijević & drakulić, 1958). accord­ ing to jovanović et al. (1972) and valjarević et al. (2015) volcanic activity evolved throughout three phases: 1. development of stratovolcanoes (emitting both tephra and viscous lava, building steep conical mounds), 2. formation of calderas, and 3. subsequent processes inside the calderas and consolida­ tion of the entire complex. 1. stratovolcanoes (complex, composite or gray volcanoes) are large, long­lived volcanoes, particularly those of andesitic com­ position that emit a combination of lava flows and tephra, building steep­sided volcanic cones. a growing lava dome might exceed 1000 m in height, as lava flows resist or slow down erosion and loss of tephra. the beautiful steep­sided cones of stratovolcanoes are among earth’s most picturesque sights (e.g. mount fuji in japan, mount rainier and mount st. helen in washington, former volcanoes in east serbia etc.). the height of volcanoes in this area undoubtely exceeded 1000 m (as the gajtan caldera is now, although eroded and shortened, nearly 700 m), with a basal diameter greater than 30 km. stra­ tovolcanoes are often transformed over time as calderas – roughly circular basins, the diameter of which can vary be­ tween 1 ­ 25 km, some of which are still preserved as relics. in general, a caldera develops by collapse after the partial or com­ plete emptying of a magma chamber. the unsupported roof of the empty chambers sinks slowly under its own weight. figure 3. microphotographs of porphyritic andesite: a) phenocryst of zoned plagioclase andesine; b) phenocryst of hornblende (red arrow); c) bluish chlorite formed over amphibole (white arrow: pl-plagioclase); d) epidote vein, thick (white arrow) and thin one (yellow arrow) in hydrothermally altered sample. g eologia c roatica 167vukoičić et al.: assessment of the geotouristic values of devil’s town, serbia 2. caldera dimensions exceeded the dimensions of the former vol­ canic cones. pyroclastic rocks as well as lava flows in the relics of former stratovolcanoes generally dip towards the volcano periphery, if not affected by subsequent tectonic events. devil’s town is, as mentioned above, within the volcanic complex of lece, a sub­volcanic pb­zn deposit, which consists of three large calderas: gajtan, devil’s town and tulari. however, at present, a significantly larger number of smaller calderas and volcanic vents are being observed (serafimovski, 1990; dragić et al., 2014). as a result of pronounced erosion ac­ companied by the effects of endogenic (volcanic) movements within the calderas. their height can not be precisely deter­ mined. the gajtan caldera is the oldest one with only the east­ ern part preserved at petrova gora. the southern part was eroded, whereas the western and northern parts were destroyed during development of the devil’s town caldera. the tulari caldera is the smallest and the best preserved suggesting that it is the youngest one. it has a complex fabric with a recognizable northward migration of the centre of effusion. the youngest ef­ fusion centre is still preserved in the form of the neck (braina) from where a radial dyke stretches towards the north. devil’s town caldera with a diameter of about 25 km is the largest and most complex, consisting of three smaller calderas: devil’s town, ivan kula and kravari. tectonic activity and faulting during the northward migration of its eastern part additionally destroyed and reworked it. the best preserved parts are at sokolovica (in the north) and at markov vis (in the south). their marginal parts are composed of pyroclastic rocks, while the in­ ternal parts (morphologically higher and closer to the inner cal­ dera) are of alternating pyroclastic rocks and lava flows. the outer zone is marked with well sorted material, according to grain size. tuffaceous sandstone and volcanic gravel overlie crystalline schists and cretaceous flysch in the footwall. vol­ canic breccias and agglomerates build the highest levels. the interior is composed of coarser volcanic products: agglomera­ tes, breccias, volcanic bombs (20­30 cm in diameter), and boul­ ders reaching a few metres in size. volcaniclastic rocks are rep­ resented by a mixture of coarse­grained blocks (from a few decimetres to a few metres in size) and fine­grained material explosively ejected from volcanoes. the pillars roofs are of an­ desite or dacite lava, which like umbrellas either protects them or slows down further erosion and destruction. 3. the presence of sinterized tuffs and younger lava flows in the gajtan caldera, including repeated volcanic activity in the tu­ lare caldera, reflects the continuation of volcanic activity within the previously formed calderas. during the final vol­ canic phases, after consolidation of the magmatic masses, ba­ sal uplift in the form of domas took place enabling the devel­ opment of radially distributed fissures through which hydrothermal solutions percolated. hydrothermal solutions, meso­ to epithermal, affected the host rocks which were sub­ jected to physical and chemical weathering and erosion. these processes finally shaped this area. the stone formations were dissected into twenty metre thick layers of weathered delluvial material (i.e. debris flow) and their growth was enabled by the existence of “caps or roofs” of more resistent material (lava flows) (fig. 4). similar forms have been noted in the high mountain ranges of the andes and alps (e.g. both sides of the brenner pass, in figure 4. a devil’s town; b the reef between devil’s town and hell’s gully; c hell’s gully; d earth pillars in devil’s town; e earth pillars in hell’s gully. g eo lo gi a c ro at ic a 168 geologia croatica 74/2 austria, italy and france etc.), where they were formed through leaching of glacial (moraine) material. spectacular forms in the garden of the gods (illinois, usa) were formed within sedi­ ments (red and white sandstone, limestone and conglomerates of carboniferous age, about 320 ma old) that were deposited hori­ zontally, but later have been tilted vertically and faulted by im­ mense mountain building forces (skinner & porter, 2000). in the sahara desert, the memuniat formation was created within the ordovician sandstone. however, in devil’s town, stone for­ mations are more abundant, larger in dimensions and more resist­ ant, providing a representative example of the diverse erosive ac­ tion of water supported by lithological differences and rare hydrothermal occurrences (fig. 5). the wider area of devil’s town is rich in ore (iron, alu­ minum, gold and silver), and demonstrates mines dating back to the 13th century and the arrival of german saxon miners (fig. 6). in fact, the saxon miners restored mines and the ore­forming sites known from the ancient and the prehistoric ages. the nearby neolithic site (5500 to 4700 b.c.) in the village of pločnik, near prokuplje, preserved a significant number of prehistoric metal­made weapons and copper tools. these artifacts suggest that this site was a centre of metallurgy in europe dating back to 5500­4800 b.c., i.e. that the copper age started in europe ear­ lier than previously understood. it is also thought that the ore was obtained from an azurite and malachite deposit from the site in the vicinity of toplica and kosanica, as neither immediate loca­ tions of ore excavation nor slag residues resulting from smelting were discovered (ćuzović et al., 2004). additionally, the re­ mains of the medieval fortification constructed on the basement of the former roman settlement of hammeum (second half of 1st century), were discovered at hisar hill (prokuplje). this site is also under state protection and considered to be a monument of great cultural importance. the entrances to the mine shafts are very narrow, which is characteristic of the castle mines. one of the three preserved mine shafts has been explored. its entrance is expanded and its length is about 800 m (http://www.djavoljavaros.com/). there are two rare hydrological phenomena in devil’s town, related to the last phases of vulcanism. extremely cold and acidic water (ph 1.5), highly mineralized (15 g / l, most of si, al, fe and s) with a hardness of about 21,050d springs in the upper part of the devil’s gully. this spring is known as the “devil’s water”. figure 5. the bird’s-eye view photograph of the devil’s town. figure 6. investigated mining shaft in devil’s тown. figure 7. adevil’s water; bred spring. g eologia c roatica 169vukoičić et al.: assessment of the geotouristic values of devil’s town, serbia one litre of water contains over 1.5 g of metal (al, fe, k, cu, ni) and 2.63 g of sulfur. due to its very low ph, this water is also a good solvent, suggesting that some amounts of al, fe and k were probably extracted from the surrounding rocks. water in the spring called “crveno vrelo (the red spring)” (to the right side of the yellow stream, about 400 m from the previously mentioned spring) is less acidic (ph 4.0) and iron­rich (198.8 mg / l). the oxidized iron along with substances which came from the sur­ rounding rocks led to changes in the water properties in the stream revealing its name “žuti potok (yellow stream)”. the wa­ ters of both springs have no healing properties, but they are a natural poison to the living world (protić, 1995; http://www. izjz­nis.org.rs/; srećković­batoćanin, d. et al., 2010) (fig. 7). 2.4. examples of similar localities in the balkans geolocalities in structure and origin similar to devil’s town (gs1) in the balkan area include: the sand pyramids (gs2) in bosnia and herzegovina and stob (gs3) and the melnik earth pyramids (gs4) in bulgaria (fig. 8). small peaks called “pyramids” appear in the southeastern­ most part of the macro region bosansko sredogorje near the vil­ lage of daničići (location šljivovice, 9 km from foča in bosnia and herzegovina). similar landmarks are noted in the vicinity, too. these forms consist of alternating pliocene clastites – con­ glomerate, gravel and sand derived in eluvial relief from the for­ mer miocene basin under the triggered action of proluvial and gravitational processes during the quaternary. the sand pyra­ mids represent a classic example of selective denudation due to the existence of more resistant layers of pliocene conglomerates in the hanging wall (lepirica, 2013). continual erosion facili­ tates their persistent growth. sculptured sand columns rise from a broad base and narrow towards the top revealing amazing geomorphological phenomena within the area. these sand pyramids were protected by a decla­ ration of the commission to preserve the national monuments of bosnia and herzegovina in 1959. at present the institution is revising the inventory of localities that have been protected up to 1992. due to its outstanding importance, specific protection mea­ sures are suggested for this locality. it needs to be evaluated in the sense of tourism, bearing in mind that it is commonly com­ pared to the devil’s town in serbia (lepirica, 2010). the stob pyramids, known as hoodoos, are located between the western foothills of rila mountain and the eastern localities of kulski rid and tsarkvishteto near the village of stob, about 5 km from the city of kocherinovo (kyustendil province) in bul­ garia. this site is very popular, in many ways like the melnik pyramids on the slopes of pirin mountain, (bulgaria) and devil’s town in serbia. the site is insufficiently explored and informa­ tion concerning it remains far behind similar localities elewhere in the world (e.g. the wheeler geological area in the usa and cappadocia in turkey). these erosive landmarks, up to 12 m in height with a stony top, up to 120 cm in diameter, occupy an area of about 7.4 ha at 600 to 750 m a.s.l. the pyramids are composed of weakly bonded neogene­quaternary sandstones and conglom­ erates deposited within the last 1–2 ma on the slope in a lacus­ trine environment. figure 8. position of geosites on the balkan peninsula. g eo lo gi a c ro at ic a 170 geologia croatica 74/2 table 1. the structure of the geosite assessment model (gam) (vujičić et al., 2011). indicators/sub-indicators description main values (mv) scientific/educational value (vse) 1. rarity number of nearby identical sites 2. representativeness didactic and exemplary characteristics of the site due to its own quality and general configuration 3. knowledge on geoscientific issues number of published papers in journals, thesis, presentations and other publications 4. level of interpretation level of interpretive possibilities on geological and geomorphologic processes, phenomena and shapes and level of scientific knowledge scenic/aesthetic (vsa) 5. viewpoints number of viewpoints accessible for pedestrians. each must be situated less than 1 km from the site. 6. surface whole surface of the site. each site is considered in quantitative relation to other sites 7. surrounding landscape and nature panoramic view quality, presence of water and vegetation, absence of human-induced deterioration, vicinity of urban area, etc. 8. environmental fitting of sites level of contrast to the nature, contrast of colours, appearance of shapes, etc. protection (vpr) 9. current condition current state of geosite 10. protection level protection by local or regional groups, national government, international organizations, etc. 11. vulnerability level of vulnerability of the geosite 12. suitable number of visitors supposed number of tourists on the site at the same time, according to surface area, vulnerability and current state of geosite additional values (av) functional values (vfn) 13. accessibility possibilities for approaching the site 14. additional natural values number of additional natural values in the radius of 5 km (geosites also included) 15. additional anthropogenic values number of additional anthropogenic values in the radius of 5 km 16. vicinity of emissive centers closeness of emissive centers 17. vicinity of important road network closeness of important road networks in the radius of 20 km 18. additional functional values parking lots, gas stations, mechanics, etc. touristic values (vtr) 19. promotion level and number of promotional resources 20. organized visits annual number of organized visits to the geosite 21. vicinity of visitors centers closeness of visitor center to the geosite 22. interpretative panels interpretative characteristics of text and graphics, material quality, size, fitting to surroundings, etc. 23. number of visitors annual number of visitors 24. tourism infrastructure level of additional infrastructure for tourist (pedestrian pathways, resting places, garbage cans, toilets etc.) 25. tour guide service if exists, expertise level, knowledge of foreign language(s), interpretative skills, etc. 26. hostelry service hostelry service close to geosite 27. restaurant service restaurant service close to geosite grades (0.00-1.00) 0.00 0.25 0.50 0.75 1.00 1. common regional national international the only occurence 2. none low moderate high highest 3. none local publications regional publications national publications international publications 4. none moderate level of processes but hard to explain to non-experts good example of processes but hard to explain to non-experts moderate level of processes but easy to explain to common visitor good example of processes and easy to explain to most visitors 5. none 1 2 to 3 4 to 6 more than 6 6. small medium large 7. low medium high utmost 8. unfitting neutral fitting 9. totally damaged (as a result of human activities) highly damaged (as a result of natural processes) medium damaged (with essential geomorphologic features preserved) slightly damaged no damage 10. none local regional national international 11. irreversible (with possibility of total loss) high (could be easily damaged) medium (could be damaged by natural processes or human activities) low (could be damaged only by human activities) none 12. 0 0 to 10 10 to 20 20 to 50 more than 50 13. inaccessible low (on foot with special equipment and expert guide tours) medium (by bicycle and other means of man-powered transport) high (by car) utmost (by bus) 14. none 1 2 to 3 4 to 6 more than 6 15. none 1 2 to 3 4 to 6 more than 6 g eologia c roatica 171vukoičić et al.: assessment of the geotouristic values of devil’s town, serbia 16. more than 100 km 100 to 50 km 50 to 25 km 25 to 5 km less than 5 km 17. none local regional national international 18. none low medium high utmost 19. none local regional national international 20. none less than 12 per year 12 to 24 per year 24 to 48 per year more than 48 year per 21. more than 50 km 50 to 20 km 20 to 5 km 5 to 1 km less than 1 km 22. none low quality medium quality high quality utmost quality 23. none low (less than 5000) medium (5001 to 10 000) high (10 001 to 100 000) utmost (more than 100 000) 24. none low medium high utmost 25. none low medium high utmost 26. more than 50 km 25–50 km 10–25 km 5–10 km less than 5km 27. more than 25 km 10–25 km 10–5 km 1–5 km less than 1 km the stob earth pyramids were declared a natural landmark in 1964. their formation, evolution and destruction are taking place in repeated stages driven by groundwater, temperature in­ version and wind. at the immediate site, two evolutionary stages could be recognized. the site is easily accessible to visitors via designated pathways and viewpoints, which offer a panoramic view over the whole geosite and nearby settlements (stob, poromi­ novo, barakovo, kocherinovo, rila). in the immediate vicinity of stob village, there are also ancient ruins that should be evalu­ ated in terms of tourism (https://www.andrey­andreev.com/en/ stob­pyramids­bulgaria/). the melnik pyramids are considered to be the most interest­ ing natural wonder in bulgaria, as well as on the balkan penin­ sula. these pyramids are similar to those at stob, but are much greater in size and spatial distribution. the melnik pyramids are located on the southwestern slope of pirin mountain at about 180 km south of sofia, in the blagoevgrad province and the munici­ pality of sandanski. the exact sites are melnik, gorna sushitsa, karlanovo, rozhen and sugarevo. this geosite has been pro­ tected since 1960 (enlarged and redeclared in 1978) over an area of 1165.6 ha. rock formations resembling pyramids are located from 350 ­ 850 m a.s.l. their variable colours and heights offer an amazing, very attractive image. the increasing number of visitors from all over the world required a number of buildings and recreation centres to be built in melnik. the melnik region consists of grayish­white pliocene sand, mixed with clay layers. it was deposited at the bottom of a shal­ low lake 3–5 ma ago. folding caused by the collision of continen­ tal plates led to the formation of mountain ranges, such as pirin, ograzden and belasica. the lake water flowed to the south and discharged into the aegean sea. in the newly formed valley, ter­ rigenous material was brought by mountain rivers and streams leading to the formation of about 500­600 m of alluvial deposits of weakly cemented and reddish sedimentary rocks. over the next thousands of years, sediments accumulated up to 120 m thick, nourished from the pirin range by mountain rivers and streams. in the variously shaped valleys the pyramid formation was addi­ tionally supported by wind action and temperature inversion. the melnik pyramids are of noteworthy shapes and of vari­ ous sizes that are subjected to changes due to the decomposition and decay of plants, such as deciduous trees, bushes and grasses that thrive there. the most visited pyramids are those located near the rozhen monastery. they are easily accessible by constructed pathways from the city of melnik to the rozhen monastery. the other attractive group of pyramids is in the village of karlanovo. although there are only four pyramids, they look impressive ex­ ceeding 100 m in height, having slopes barren of vegetation and with flattened peaks. the stony caps have the same protective role against erosion, as in the previously mentioned localities. the small city of melnik, additionally contributes to the attractive­ ness for tourists. renowned for its authentic architecture from the renaissance era it is declared an architectural reserve. addi­ tional anthropogenic tourist values include: the kordopulov house – a large house from the bulgarian national revival period, wine museum, rozhen monastery – the biggest orthodox church in the pirin mountain area. 2.5. methodology andesite samples were optically analyzed using a petrographic polarized microscope for transmitted light (leica dmlsp), which is connected to a leica dfc290 hd camera over the pro­ gram las v4. 2.5.1. m-gam model previous geosite assessment models involved geosite assessment criteria adjusted for tourists (pralong, 2005; serrano & gonzález­trueba, 2005; hose, 2007; pereira et al., 2007; zouros, 2007; reynard, 2008; reynard, 2009; reynard et al., 2016; reynard & brilha, 2018) and ex­ perts (bruschi & cendrero, 2005; coratza & giusti, 2005; hose, 2007; white & wakelin­king, 2014). vujičić et al. (2011) proposed a model for the evaluation of ge­ olocalities (gam) based on the experts’ opinion, whereas tomić & božić (2014) modified the gam model into the m­gam model, and based it on both the opinions of experts and visitors. this study includes the values of experts for all 27 sub­indi­ cators in gam (table 1) along with the tourist values (im) (table 2), which have already been presented by božić & tomić (2015). in the original gam model two important indicators are included: main values and additional values, and then divided into 12 and 15 indicators respectively, each scored between 0 and 1. this kind of model is made according to two general kinds of values: main – mostly generated by the geosite’s natural characteristics; and ad­ ditional – mostly generated by modifications for its use by visitors. the main values are conducted by three groups of indicators: sci­ entific/educational (vse), scenic/aesthetical values (vsa) and pro­ tection (vpr) while the additional values are divided into two groups of indicators, functional (vfn) and touristic values (vtr). the main and additional values are presented in table 1. g eo lo gi a c ro at ic a 172 geologia croatica 74/2 the gam is defined as a simple equation, a sum of 12 sub­ indicators of the main values, and 15 sub­indicators of the ad­ ditional values which are graded from 0 to 1: gam = mv + av (1) where mv and av represent the symbols for the main and addi­ tional values. we derive these two equations, because main and additional values consist of three or two groups of sub­indica­ tors, mv = vse + vsa + vpr (2) av = vfn + vtr (3) now that we know that each group of indicators consists of several sub­indicators, equations (2) and (3) can be written as fol­ lows: mv = vse + vsa + vpr = i= ∑ 1 12 simvi , where 0 ≤ simvi ≤ 1 (4) av = vfn + vtr = j= ∑ 1 15 siavi , where 0 ≤ siavi ≤ 1 (5) here, simvi and siavj represents 12 sub­indicators of the main values (i = 1…,12) and 15 subindicators ( j = 1,...,15) of the addi­ tional values. a matrix of main (x axes) and additional values (y axes) is created according to the results. the matrix is divided into nine fields represented by z(i,j), (i,j=1,2,3). depending on the final score, each geosite will fit into a certain field. for example, if a geosite’s main values are 7 and additional are 4, the geosite will fit into the z21 field (figure 9). high precision and applicability at several geolocalities (tomić et al., 2015; jonić, 2018; antić et al., 2019; vuković & antić, 2019; tomić et al., 2020) were the main reasons to introduce the importance factor (im) that has been presented by božić & tomić (2015). the importance factor (im) is the mean value for each sub­indicator given by tourists. a few more papers concerning the use of m­gam (păl & albert, 2018; antić table 2. values given by experts and visitors for each sub-indicators in the gam model. main indicators / sub-indicators (gam) expert’s estimation (0-1) im (m-gam) total estimation gs1 gs2 gs3 gs4 gs1 gs2 gs3 gs4 i scientific/educational values (vse) 2.12 1.58 1.47 1,88 1. rarity 0.75 0.50 0.25 0.25 0.89 0.67 0.45 0.22 0.22 2. representativeness 1.00 0.75 0.75 1.00 0.79 0.79 0.59 0.59 0.79 3. knowledge on geoscientific issues 0.50 0.25 0.50 0.50 0.45 0.23 0.11 0.23 0.23 4. level of interpretation 0.50 0.50 0.50 0.75 0.85 0.43 0.43 0.43 0.64 ii scenic/aesthetic (vsa) 2.22 1.72 2.79 2.96 5. viewpoints 0.75 0.50 1.00 1.00 0.79 0.59 0.40 0.79 0.79 6. surface 0.75 0.50 1.00 1.00 0.54 0.41 0.27 0.54 0.54 7. surrounding landscape and nature 0.75 0.75 1.00 1.00 0.95 0.71 0.71 0.95 0.95 8. environmental fitting of sites 0.75 0.50 0.75 1.00 0.68 0.51 0.34 0.51 0.68 iii protection (vpr) 1.8 1.31 1.90 2.09 9. current condition 0.75 0.75 0.75 0.75 0.83 0.62 0.62 0.62 0.62 10. protection level 0.75 0.25 0.75 1.00 0.76 0.57 0.19 0.57 0.76 11. vulnerability 0.50 0.50 0.50 0.50 0.58 0.29 0.29 0.29 0.29 12. suitable number of visitors 0.75 0.50 0.75 1.00 0.42 0.32 0.21 0.42 0.42 iv functional values (vfn) 1.66 2.28 2.89 3.24 13. accessibility 0.75 0.75 0.75 0.75 0.75 0.56 0.56 0.56 0.56 14. additional natural values 0.25 0.50 0.75 1.00 0.71 0.18 0.36 0.53 0.71 15. additional anthropogenic values 0.25 0.50 0.75 1.00 0.70 0.18 0.35 0.53 0.70 16. vicinity of emissive centers 0.25 0.50 0.75 0.75 0.48 0.12 0.24 0.36 0.36 17. vicinity of important road network 0.75 0.75 0.75 0.75 0.62 0.47 0.47 0.47 0.47 18. additional functional values 0.25 0.50 0.75 0.75 0.59 0.15 0.30 0.44 0.44 v touristic values (vtr) 3.9 1.66 4.67 5.78 19. promotion 1.00 0.25 0.75 0.75 0.85 0.85 0.21 0.64 0.64 20. organized visits 1.00 0.25 0.75 1.00 0.56 0.56 0.14 0.42 0.56 21. vicinity of visitors centers 0.25 0.25 0.50 0.75 0.87 0.22 0.22 0.44 0.65 22. interpretative panels 0.00 0.25 0.75 0.75 0.81 0 0.20 0.61 0.61 23. number of visitors 0.75 0.25 0.50 1.00 0.43 0.32 0.11 0.22 0.43 24. tourism infrastructure 0.75 0.25 0.75 1.00 0.73 0.55 0.18 0.55 0.73 25. tour guide service 0.50 0.25 0.75 0.75 0.87 0.44 0.22 0.65 0.65 26. hostelry service 0.50 0.25 0.75 1.00 0.73 0.37 0.18 0.55 0.73 27. restaurant service 0.75 0.25 0.75 1.00 0.78 0.59 0.20 0.59 0.78 gs1 – devil’s town (serbia), gs2 – sand pyramids (bosnia and herzegovina), gs3 – stob pyramids (bulgaria), gs4 – melnik pyramids (bulgaria) im – importance factor. g eologia c roatica 173vukoičić et al.: assessment of the geotouristic values of devil’s town, serbia et al., 2020; bratić et al., 2020; tomić et al., 2021) have been published in the most recent few months. the importance factor (im) is defined, as: im iv k kk k = =∑ 1 (6) where ivk is the assessment/score of one visitor for each sub­in­ dicator and k is the total number of visitors. note that the im pa­ rameter can have any value in the range from 0.00 to 1.00. finally, the modified gam equation is defined in the following form: m – gam = mv * av (7) mv im mvi i i n = = ∑ * 1 (8) av im avj j i n = = ∑ * 1 (9) as it can be seen from the m-gam equation, the value of the im­ portance factor (im), which is rated by visitors (for each sub­in­ dicator separately) is multiplied with the value given by experts (also separately for each sub­indicator). this is done for each sub­ indicator in the model. therefore, the values of m-gam sub­in­ dicators are always less or equal to the gam values (table 2). 3. results and discussion the unique geomorphological phenomenon in serbia, the devil’s town, (gs1), was being considered with respect to three similar localities on the balkan peninsula, the sand pyramids (gs2) in bosnia and herzegovina, and the stob (gs3) and melnik pyra­ mids (gs4) in bulgaria. geosites were evaluated using the above mentioned methodology (m­gam). values for the main indica­ tors and sub­indicators are given in table 2, whereas the final re­ sults of these values are presented in table 3 and figure 9. according to the results obtained, devil’s town (gs1) dis­ plays the highest scientific/educative value of the analyzed ge­ osites, being particularly emphasized by its representativeness. this could be explained by the high didactic and educational characteristics of the locality itself. the melnik pyramids (gs4) are also known by their representativeness due to features of the geosite. however, the sand pyramids (gs2) and stob pyramids (gs3) geosites are of significantly lower scientific value. the knowledge on their geoscientific issues has the lowest value within the analyzed sub­indicators of scientific value of all of the analyzed geosites. the lowest number of publications relates to the sand pyramids (gs2), while articles for the rest of geosites were commonly published in local publications, less commonly in regional and national journals. the stob (gs3) and melnik pyramids (gs4) also record low values for rarities, as both ge­ osites are in bulgaria in the circled area of 100 km. concerning scenic/aesthetic values, the melnik pyramids (gs4) exhibit the highest values due to the amazing landscape and beautiful natural scenery in the vicinity: a number of desig­ nated viewpoints, contrasting colours and shapes, as well as the overall appearance of the geosite. the stob pyramids (gs3) geo­ site has a lower aesthetic value in spite of the breathtaking pano­ ramic view, plenty of easy accessible pathways and viewpoints and contrasting colour with the surrounding nature. the geosite devil’s town (gs1) is of exceptional scenic/aesthetic value re­ garding nature and its vicinity. the lowest value is ascribed to its spatial distribution in comparison with the area of other geosites (gs4 and gs3). the lowest aesthetic value within the analyzed geosites relates to the sand pyramids (gs2) due to a smaller area and a lesser number of landscape areas. considering protection, which is a very important indicator of the main values, only small differences were noted between these four geosites. the lowest level of protection goes to the sand pyramids (1.31). some higher values were exhibited at dev­ il’s town (1.80) and the stob pyramids (1.90). the geolocality melnik is reasonably the highest ranked (2.09) as it has been un­ der protection much longer than the other three geosites. the big­ gest differences among the sub­indicators were recorded for the level of protection and accommodation capacities. the largest areas are occupied by the geosites melnik (gs4) and stob (gs3), hence their values are the highest. in contrast, the geolocality sand pyramids (gs2) covers the smallest area and thus displays the lowest value. considering the additional values, particularly the natural and anthropogenic ones, the best results were indicated by the geosite melnik (gs4). being well­known for its natural values and surrounding settlements of rich cultural­historical heritage, melnik (gs4) displays the highest additional, natural and anthro­ pogenic values. stob pyramids (gs3) are also surrounded by plenty of natural and anthropogenic values, whereas the remain­ ing two geosites (gs1 and gs2) are less worthy due to their dis­ tance from other attractive tourist destinations. the vicinity of emissive centers is among the functional values of the lowest value in all of the analyzed geosites. however, some higher valu es table 3. overall ranking of the analyzed geosites using m-gam. values main additional vse+vsa+vpr ∑ vfn+vtr σ field gs1 2.12+2.22+1.80 6.14 1.66+3.90 5.56 z22 gs2 1.58+1.72+1.31 4.61 2.28+1.66 3.94 z21 gs3 1.47+2.79+1.90 6.16 2.89+4.67 7.56 z22 gs4 1,88+2,96+2,09 6,93 3,24+5,78 9,02 z22 gs1 – devil’s town (serbia), gs2 – sand pyramids (bosnia and herzegovina), gs3 – stob pyramids (bulgaria), gs4 – melnik pyramids (bulgaria) figure 9. position of evaluated geosites in m-gam matrix. g eo lo gi a c ro at ic a 174 geologia croatica 74/2 were displayed by geosites melnik and stob in comparison with devil’s town and the sand pyramids. the important emissive centre in melnik (gs4) is the city of sandanski, approximately 20 km distant. this city in blagoevgrad province is the third big­ gest city and one of the famous spas in bulgaria. the nearest emissive centre to the stob pyramids (gs3) is blagoevgrad, at about 15 km. sarajevo, some 60 km away, is the nearest emissive centre to the sand pyramids (gs2). finally, the cities of niš and kruševac, being about 90 km distant, are the nearest to devil’s town. melnik (gs4), has the highest touristic value among the an­ alyzed geosites, being particularly noteworthy for its touristic infrastructure among the sub­indicators (designed long pedes­ trian pathways, resting places at viewpoints), hostelry and res­ taurant services placed next to the pyramids. however, the num­ ber of visitors is not in accordance with promotional activities, remaining insufficient and at a low level. slightly lower touristic value displays stob (gs3), whereas the geosite devil’s town (gs1) remains far behind melnik and stob due to insufficient interpre­ tative panels, the distance from visitor centers and hostelry ser­ vices. the advantage of devil’s town in comparison to the other analyzed localities is the significant level of promotional activi­ ties. the lowest touristic values exhibited by the sand pyramids (gs2) having low values of all the sub­indicators. according to the final results for all the analyzed geosites, given in table 3, are the determined positions in m­gam matrix (fig. 9). on the basis of the final results (table 3) it could be con­ cluded that in the future attention should be paid to the additional values at geosites gs1 and gs2. sub­indicators obtained low valu es due to the distance from broadcasting centres as well as visitor centres, and the geosite lacked accommodation services, interpretative boards and additional functional values. in addi­ tion to these elements, there is a high level of sensitivity of geo­ sites to natural and human interferences. in spite of all the geo­tourist values that the site of the dev­ il’s town has, the manager of ad “planinka” from kuršumlija must be ready for the development of competition in the wider area, while at the same time tightening the criteria for assessing the load on the environment. this company must improve the quality of the resulting solutions, innovate procedures and learn to continue the improvement of activities and successful achieve­ ment in competitive surroundings (sütőová et al., 2018). 4. summary and conclusion it could be concluded that the highest differences within the ana­ lyzed geolocalities display touristic values that rely on tourism development in the country where the geosite is located and on tourist valorization of geosites. sub­indicators from this group, such as promotion, organized visits, interpretative panels, tour­ ism infrastructure, guidelines, accommodation and restaurant services, could be easily changed and improved by human activi ty and investment in tourism development. according to the position of the evaluated geosites in the gem matrix, along with the final results presented in tables 2 and 3, the absolute domination of melnik (gs4) among the ana­ lyzed geosites is apparent. however, the inevitable upgrading of additional values for a better position in the matrix is necessary. the sand pyramids (gs2) occupy the lowest position in the matrix, having significant main values, but unfortunately display­ ing the lowest additional values. this suggests the high potential of the sand pyramids and direct progress in geotourism develop­ ment with the improvement of additional values, particularly touristic ones. devil’s town (gs1) is most similar to the stob pyramids (gs2) regarding the main values. concerning the additional valu es, both geosites belong to the moderate level. nevertheless, the stob pyramids occupy a higher position in the matrix due to higher additional values. thus, the appropriate increase of func­ tional and touristic values would contribute to a better position in matrix. furthermore, the management of each geosite should focus on a specific market segment shaping and directing the develop­ ment of the site towards the specific needs and preferences of tourism segments. therefore, this research indicates what is im­ portant for the different segments when visiting a geosite so it can be used as a framework for tourism planning. having said this, the management of each geosite should develop a tourism strate gy depending on whether it intends to become a destination for mass tourism or to attract smaller specific tourism segments such as pure geotourists and thus base the development of a geosite ac­ cording to their needs and preferences. in order to strike the right balance between the offer for general tourists and pure geotourists in the future, we should keep tourism development in a sustainable form, taking care of the protection of geosites and reducing the negative impact of tourism, which can be triggered by mass tourist visits. acknowledgment we are very grateful to the enterprise ‘’planinka’’ in kuršumlija for providing official records and for the efforts they have made to conduct surveys of visitors (tourists). references antić, a. & tomić, n. (2017): geoheritage and geotourism potential of the homolje area (eastern serbia).– acta geoturistica, 8/2, 67–78. doi: 10.1515/agta­2017­0007 antić, a., tomić, n. & marković, s. (2019): karst geoheritage and geotourism potential in the pek river lower basin (eastern serbia).– geographica pannonica, 23/1, 32–46. doi: 10.5937/gp23­20463 antić, a., tomić, n. & marković, s. (2020): karst­based geotourism in eastern carphatian serbia: exploration and evaluation of natural stone bridges.– geo­ conservation research, 3/2, 62–80. doi: 10.30486/gcr.2020.1903486.1023 belij, s. (2007): geodiverzitet i geonasleđe – savremeni trend razvoja geomorfologije u svetu i kod nas.– zbornik geografskog intituta jovan cvijić, 57, 65–70. doi: 10.2298/ijgi0757065b belij, s. (2008): geodiverzitet i geonasleđe u razvoju geomorfologije i zaštiti prirode.– zaštita prirode, 58/1–2, 5–14. belij, s. (2009): stanje i zaštita geodiverziteta i objekata geonasleđa u srbiji.– zaštita prirode, 60/1–2, 349–358. boškov, j., kotrla, s., jovanović, m., tomić, n., lukić, t. & rvović, i. (2015): аpplication of the preliminary geosite assessment model (gam): the case of the bela crkva municipality (vojvodina, north serbia).– geographica pannonica,19/3, 146–152. božić, s. & tomić, n. (2015): canyons and gorges as potential geotourism destina­ tions in serbia: comparative analysis from two perspectives – general geotourists’ and pure geotourists’.– open geoscence., 7/1, 531–546. doi: 10.1515/geo­2015­ 0040 braga, j.c. (coord.) (2002): propuesta de estrategia andaluza para la conservación de la geodiversidad [andalucia strategy proposal for the conservation of geodiversity – in spanish].– junta de andalucía, consejería de medio ambiente, 105 p. bratić, m., marjanović, m., radivojević, a.r. & pavlović, m. (2020): m­gam method in function of tourism potential assessment: case study of the sokobanja basin in eastern serbia.– open geosciences, 12, 1468–1485. doi: doi: 10.1515/geo­2020­0116 brilha, j. (2005): património geológico e geoconservação.– a conservação da natureza na suavertente geológica. viseu: palimage. bruschi, v.m. & cendrero, a. (2005): geosite evaluation. can we measure in­ tangible values?– il quaternario, 18/1, 293–306. g eologia c roatica 175vukoičić et al.: assessment of the geotouristic values of devil’s town, serbia burek, c.v. & prosser, c.d. (2008): the history of geoconservation: an introduc­ tion.– in: burek, c.v. & prosser, c.d. (eds.): the history of geoconserva­ tion. geological society, london, 1–5. doi: 10.1144/sp300.1 cgiar consortium for spatial information. srtm 90m digital elevation data. 2017. retrieved from: http://srtm.csi.cgiar.org/ (accessed: 22 february 2017). coratza, p. & giusti, c. (2005): methodological proposal for the assessment of the scientific quality of geomorphosites.– il quaternario, 18/1, 307–313. ćuzović, m., stajić, d. & ostojić, m. (2004): from unhealthy rock to black gold.– jp peu, resavica, 315 p. dimitrijević, m. & drakulić, n. (1958): kristalasti škriljci jablanice.– zbornik rudarsko­geološkog fakulteta, 6, 1–32. dimitrijević, m.d. & dimitrijević, m.n. (1974): o genezi ”dijabaz­rožnačke formacije“.– geološki glasnik, 7, 333–345. djavolja varoš: http://www.djavoljavaros.com/ (accessed: 28 february 2017). djurović, p. & mijović, d. (2006): geoheritage of serbia­representative of its to­ tal geodiversity.– zbornik radova geografskog fakulteta u beogradu, 54, 5–18. (in serbian). dowling, r.k. (2011): geotourism’s global growth.– geoheritage, 3/1, 1–13. doi: 10.1007/s12371­010­0024­7 dragić, d., miskovic, a., hart, c., tosdal, r., fox, ph. & glisic, s. (2014): spatial and temporal relations between epithermal and porphyry style mineraliza­ tion in the lece magmatic complex, serbia.– poster in seg conference 2014, keystone, co, usa. geoliss (geological information system of serbia; web publishing by geoliss team faculty of mining and geology, university of belgrade) (2020): basic geological map. belgrade: ministry of energy, development and environmental protection of republic of serbia. retrieved from http://geoliss.mre.gov.rs (accessed: 05 sep­ tember 2020). grandgirard, v. & szepesi, a. (1997): geomorphology and management of na­ tural heritage (the protection of the geotopes, a new task in geomorphology).– noosfera, 3, 59–65. gray, m. (2008): geodiversity: developing the paradigm.– proceedings of the geolo­ gists’ association, 119/3­4, 287–298. doi: 10.1016/s0016­7878(08)80307­0 gray, m. (2013): geodiversity: valuing and conserving abiotic nature.– wiley­black­ well. chichester, u.k. hose, t.a. (2000): european geotourism – geological interpretation and geoconser­ vation promotion for tourists.– in: barretino, d., wimbledon, w.p. & gallego, e. (eds.): geological heritage: its conservation and management. madrid: instituto tecnologico geominero de espana, 127–146. hose, t.a. (2005a): geo­tourism ­ appreciating the deep side of landscapes.– in: no­ velli, m. (ed.): niche tourism: contemporary issues, trends and cases. elsevier science, oxford, 27–37. hose, t.a. (2005b): geotourism and interpretation.– in: dowling, r.k. & new­ some, d. (eds.): geotourism. elsevier, oxford, 221–241. doi: 10.1016/b978­0­ 7506­6215­4.50020­8 hose, t.a. (2007): geotourism in almeria province, southeast spain.– tourism, 55, 259–276. hose, t.a. (2008): the genesis of geotourism and its management implications.– in: abstracts volume, 4th international conference, geotour 2008, geotourism and mining heritage, krakow. hose, t.a., marković, s.b., komac, b. & zorn, m. (2011): geotourism – a short introduction.– acta geographica slovenica, 51/2, 339–342. doi: 10.3986/ ags51301 hose, t.a. & vasiljević, đ.a. (2012): defining the nature and purpose of modern geotourism with particular reference to the united kingdom and south­east eu­ rope.– geoheritage 4/1–2, 25–43. doi: 10.1007/s12371­011­0050­0 institute of public health of nis: (http://www.izjz­nis.org.rs/) (accessed: 4 december 2010) jonić, v. (2018): comparative analysis of devil s town and bryce canyon geosites by applying the modified geosite assessment model (m­gam).– researches reviews of the department of geography, tourism and hotel management, 47/2, 113–125. jovanović, m., karajičić, lj., karamata, s. & vukanović, m. (1972): novi pogledi na razvoj vulkanizma u području leckog andezitskog kompleksa.– geol. anali balk. pol., 37/2, 165–177. joyce, e.b. (2006): geomorphological sites and the new geotourism in australia.– geological society of australia. melbourne. (http://web.earthsci.unimelb.edu.au/ joyce/heritage/geotourismreviewebj.htm) kostić, b., šarić, k., cvetković, v., krstekanić, n., pantelić, n. & bosić, d. (2017): a reinterpretation of the geological map of northwestern part of lece volcanic complex.–­ in: 13th workshop on alpine geological studies, zlatibor mts., belgrade, university of belgrade­faculty of mining and geology. karamata, s., stojanov, r., serafimovski, t. et al. (1992): tertiary magma­ tism in the dinarides of the vardar zone and the serbo­macedonian massif.– geo­ logica macedonica, 6/1, 127–186. lepirica, a. (2010): prirodni uslovi i mogućnosti za razvoj turizma u mezoregiji gor­ nje podrinje.– zbornik radova pmf, 7, 57–79. lepirica, a. (2013): geomorfologija bosne i hercegovine.– biblioteka university book, sarajevo publishing, 208 p. lješević, m.a. (2002): geodiverzitet kao uslov i iskaz životne sredine.– zbornik ra­ dova pmf, 50, 17–32. malašević, m., vukanović, m., brković, t., оbradinović, z., karajičić, lj., stanisavljević, r., dimitrijević, m. & urošević, m. (1974): basic geological map 1:100.000, kuršumliја k 34­31, savezni geološki zavod, belgrade. miladinović, z., ilić, m. & simić, v. (2010): gemstone deposits of lece volcanic complex (south serbia).– in: xix congress of carpathian­balkan geological as­ sociation, thessaloniki, greece, 23­26th september, akademichno izdatelstvo prof. marin drinov, bulgarian academy of sciences sofia. geologica balcanica, 39/1–2, 253–254. mijović, d. & miljanović, d. (1999): naučni i obrazovni kriterijumi evaluacije geonasleđa uplaniranju zaštite prirodnih predela.– zaštita prirode 51/2, 133–139. mijović, d. (2002): menadžment objekata geo­nasleđa u srbiji ­ put ka geoturizmu.– zaštita prirode, 53/2, 135–142. mijović, d., rundić, lj. & milovanović, d. (2005): zaštita geonasleđa u sr­ biji i pravci razvoja.– in: zbornik radova drugog naučnog skupa o geonasleđu srbije. zavod za zaštitu prirode srbije, beograd, 17–21. newsome, d. & dowling, r.k. (2006): the scope and nature of geotourism.– in: dowling, r.k. & newsome, d. (eds.): geotourism, elsevier, oxford, 3–25. doi: 10.1016/b978­0­7506­6215­4.50009­9 newsome, d. & dowling, r.k. (2010): geotourism: the tourism of geology and landscape.– goodfellow publishers, oxford. doi: 10.23912/978­1­906884­09­3­21 nojković, s. & mijović, d. (1998): zaštita geo­nasleđa u srbiji nekad i sad.– zaštita prirode, 50, 439–442. păl, m. & albert, g. (2018): comparison geotourism assessment models: an ex­ periment in bakony–balaton unseco global geopark, hungary.– acta geoturi­ stica, 9, 1–13. panizza, m. & piacente, s. (2003): geomorfologia culturale.– piatogora editrice, bologna, 350 p. pereira, p., pereira, d. & caetano alves, m.i. (2007): geomorphosite as­ sessment in montesinho natural park (portugal).– geographica helvetica, 62/3, 159–168. doi: 10.5194/gh­62­159­2007 pešut, d. (1976): geology, tectonics and metallogeny of lece massif.– rasprave za­ voda za geološka i geofizička istraživanja, 14, 1–59. (in serbian, english summa­ ry). pralong, j.p. (2005): a method for assessing the tourist potential and use of geomor­ phological sites.– géomorphologie. relief, processus, environnement, 11/3, 189–196. doi: 10.4000/geomorphologie.350 pralong, j.p. & reynard, e. (2005): a proposal for a geomorphological sites clas­ sification depending on their tourist value.– il quaternario, 18/1 (volume speciale), 313–319. pralong, j.p. (2006): géotourisme et utilisation de sites naturels d’intérêt pour les sciences de la terre. les régions de crans­montana­ sierre (valais, alpes suisses) et chamonix­mont­blanc (haute­savoie, alpes françaises).– travaux et recherch­ es n 32, lausanne, institutde géographie, 224 p. protić, d. (1995): mineral and thermal waters of serbia.– geoinstitute, special edi­ tions, 17, belgrade, 77. (in serbian) reis, r.p. & henriques, m.h. (2009): approaching an integrated qualification and evaluation system for geological heritage.– geoheritage, 1/1, 1–10. doi: 10.1007/ s12371­009­0002­0 reynard, e. (2008): scientific research and tourist promotion of geomorphological heritage.– geografia fisica e dinamica quaternaria, 31/2, 225–230. reynard, e. (2009): the assessment of geomorphosites.– in: reynard, e., coratza, p. & regolini­bissig, g. (eds): geomorphosites. pfeil verlag, münchen, 63–72. reynard, e., perret, a., bussard, j., grangier, l. & martin, s. (2016): integrated approach for the inventory and management of geomorphological heritage at the regional scale.– geoheritage, 8, 43–60. doi: 10.1007/s12371­015­ 0153­0 reynard, e. & brilha, j. (2018): geoheritage: assessment, protection, and ma­ nagement.– elsevier, amsterdam, 482 p. ristić, d., vukoičić, d., nikolić, m., dragojlović, j. & milentijević, n. (2018): prirodni resursi u funkciji razvoja zelenog turizma na području opštine kuršumlija.– ecologica, 25/92, 787–793. rocha, j., brilha, j. & henriques, m.h. (2014): assessment of the geological heritage of cape mondego natural monument (central portugal).– proceedings of the geologists’ association, 125/1, 107–113. doi: 10.1016/j.pgeola.2013.04.005 sadry, b.n. (2009): fundamentals of geotourism: with special emphasis on iran.– samt publisher, tehran, 220 p. schmidt, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine­ carpathian­dinaridic orogenic system: correlation and evolution of tectonic units.– swiss journal of geosciences, 101/1, 139–183. doi: 10.1007/s00015­008­1247­3 g eo lo gi a c ro at ic a 176 geologia croatica 74/2 serafimovski, t. (1990): metallogeny of the lece­chalkidiki zone.– unpub. ph.d. thesis. university of štip, macedonia, 380 p. (in macedonian) serrano, e. & gonzález­trueba, j.j. (2005): assessment of geomorphosites in natural protected areas: the picos de europa national park (spain).– géomor­ phologie. formes, processus, environnement, 11/3, 197–208. doi: 10.4000/geo­ morphologie.364 skinner, b.j. & porter, s.c. (2000): the dynamic earth: an introduction to physi­ cal geology, 4th edition.– american museum of natural history, new york; john wiley & sons, 575 p. sütöová, a., zgodavová, k. & lajczyková, m. (2018): quality and effec­ tiveness evaluation of the geological services using cedac method.– acta montanistica slovaca, 23/1, 18–25. srećković­batoćanin, d., vukoičić, d., papović, o., milovanović, d., kićović, d. & đekić, t. (2010): devil’s city­history of development and touristic potentials.– in: proceedings of the international symposium geoecolo­ gy­xxi century, geoeco, žabljak­nikšić, 21­24 september, 257–268. (in serbian, with english abstract). stajević, b. (2004): geochemical haloes of gold in the lece ore field (southern ser­ bia).– annales géologiques de la péninsule balkanique, 65 (2002–2003), 93–99. doi: 10.2298/gabp0301093s stanković, s.m. (2004): turistička valorizacija geomorfoloških objekata geo­nasleđa srbije.– glasnik srpskog geografskog društva, 84/1, 79–88. tičar, j., tomić, n., valjevac, b.m., zorn, m., marković, b.s. & gavrilov, b.m. (2018): speleotourism in slovenia: balancing between mass tourism and geoheritage protection.– open geoscience, 10/1, 344–357. doi: 10.1515/geo­2018­0027 tomić, n. (2011): the potential of lazar canyon (serbia) as a geotourism destination: inventory and evaluation.– geographica pannonica, 15/3, 103–112. tomić, n. & božić, s. (2014): a modified geosite assessment model (m­gam) and its application on the lazar canyon area (serbia).– international journal of envi­ ronmental research, 8/4, 1041–1052. tomić, n., marković, b.s., korać, m., mrđić, n., hose, a.t., vasiljević, a.đ., jovičić, m. & gavrilov, b.m. (2015): exposing mammoths: from loess research discovery to public palaeontological park.– quaternary internatio­ nal, 372/22, 142–150. doi: 10.1016/j.quaint.2014.12.026 tomić, n., marković, s., antić, a. & tešić, d. (2020): exploring the potential for geotourism development in the danube region of serbia.– international journal of geoheritage and parks, 8/2, 123–139. tomić, n. & košić, k. (2020): developing the spa assessment model (sam) and its application on the kopaonik­jastrebac spa zone (serbia).– tourism manage­ ment perspectives, 36, 100753. doi: 10.1016/j.tmp.2020.100753 tomić, n., sepehriannasab, b., marković, s.b., hao, q. & lobo, h.a.s. (2021): exploring the preferences of iranian geotourists: case study of shadows canyon and canyon of jinns.– sustainability, 13/2, 798. d o i : 1 0 . 3 3 9 0 / su13020798 tosdal, r.m. (2012): u­pb shrimp­rg ages and trace element geochemistry of the kiseljak and yellow creek porphyry cu­au prospects, southern serbia.– dunav resources doo internal report, 21 p. valjarević, a., srećković­batoćanin, d., živković, d. & perić, d. (2015): gis analysis of dissipation time of landscape in the devil’s city (serbia).– acta montanistica slovaca, 20/2, 148–155. valjarević, a., vukoičić, d. & valjarević, d. (2017): evaluation of the tou­ rist potential and natural attractivity of the lukovska spa.– tourism management perspectives, 22, 7–16. doi: 10.1016/j.tmp.2016.12.004 vasiljević, dj.a., marković, s.b., hose, t.a., smalley, i., o’hara­ dhand, k., basarin, b., lukić, t. & vujičić, m.d. (2011): loess towards (geo) tourism – proposed application onloess in vojvodina region (north serbia).– acta geographica slovenica, 51/3, 391–406. vasiljević, dj.a. (2015): geodiverzitet i geonasleđe vojvodine u funkciji zaštite i turizma. doktorska disertacija.– departman za geografiju, turizam i hotelijerstvo, prirodno­matematički fakultet, univerzitet u novom sadu. vujičić, m.d., vasiljević, d.a., marković, s.b., hose, t.a., lukić, t., hadžić, o. & janićević, s. (2011): preliminary geosite assessment model (gam) and its application on fruška gora mountain, potential geotourism desti­ nation of serbia.– acta geographica slovenica, 51/2, 361–377. doi: 10.3986/ ags51303 vukanović, m., dimitrijević, m., dimitrijević, m., karajičić, lj., rajčević, d., navala, m., urošević, m., malešević, m., trifunović, s., serdar, r. & atin, b. (1975): basic geological map 1:100.000, sheet podujevo k 34­43, savezni geološki zavod, belgrade. vukoičić, d., milosavljević, s., valjarević, a., nikolić, m. & srećković­batoćanin, d. (2018): the evaluation of geosites in the terri­ tory of national park „kopaonik“ (serbia).– open geoscience, 10, 618–633. doi: 10.1515/geo­2018­0049 vuković, s. & antić, a. (2019): speleological approach for geotourism develop­ ment in zlatibor county (west serbia).– turizam, 23/1, 53–68. doi: 10.5937/turi­ zam23­21325 white, s. & wakelin­king, g.a. (2014): earth sciences comparative matrix: a comparative method for geoheritage assessment.– geographical research, 52/2, 168–181. doi: 10.1111/1745­5871.12062 zouros, n.c. (2007): geomorphosite assessment and management in protected areas of greece. the case of the lesvos island coastal geomorphosites.– geographica helvetica, 62/3, 169–180. doi: 10.5194/gh­62­169­2007 2021 | 74/1 | 85–97 | 8 figs. | 2 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction slovenia features multiple alluvial plains that are naturally con­ ducive to the exploitation of mineral resources: two are located in north eastern slovenia, specifically the mura and prekmurska plains (mursko polje and prekmursko polje); next there is the drava and ptuj plain (dravsko polje and ptujsko polje) and finally the krško and brežice plain (krško polje and brežiško polje) in eastern slovenia. these are all characterised by relatively shal­ low groundwater. the exploitation of mineral resources in these areas takes place via a combination of dry extraction and the placer mining of various sand fractions of the mineral resources. the lower savinja valley (spodnja savinjska dolina) is another alluvial plain. however, due to its relative shallowness, it is irrele­ vant in terms of mineral resources (figure 1). below we discuss the situation in the drava and ptuj plain as an example of the im­ pact that an implemented decree (decree on the river basin management plan for the danube basin and the adriatic sea ba­ sin; official gazette of rs, no. 61/11, 49/12 and 67/16) has on the exploitation of mineral resources. natural resources self-sufficiency – how to balance groundwater protection and mineral resources exploitation – pleterje case, slovenia: legal and geological aspects senko pličanič1, željko pogačnik2, eva koren3 and goran vižintin3 1 university of ljubljana, faculty of law, poljanski nasip 2, 1000 ljubljana, slovenia; (senko.plicanic@pf.uni-lj.si) 2 georudeko, geologija rudarjenje in ekologija d.o.o., anhovo 1, 5210 deskle, slovenia; (zeljko.pogacnik@georudeko.si) 3 university of ljubljana, faculty of natural sciences and engineering, aškerčeva 12, 1000 ljubljana, slovenia; (eva.koren@guest.arnes.si, goran.vizintin@guest.arnes.si) doi: 10.4154/gc.2021.02 abstract the purpose of this article is to showcase opportunities for local communities to demonstrate selfsufficiency with respect to natural resources (gravel and sand) in the east of slovenia. limitations put in place for the exploitation of mineral resources by applicable regulations in the light of groundwater protection were analysed particularly in the context of mining undertaken in an area of shallow alluvium with a shallow groundwater table. it is essential that land disturbance (from mining activity) complies with the environmental limitations imposed by both eu and slovenian law. the study highlights the factors directly indicating the inadequacy of the applicable regulations in slovenia in relation to mining in areas of shallow groundwater; those limitations put in place the exploitation of mineral resources as unlawful works. this article outlines how such limitations negatively affect local communities’ self-sufficiency and the region with natural resources, specifically mineral resources. to this end, when selecting which alluvial plain to test, we focused on the area of the drava and ptuj plain (dravsko polje and ptujsko polje) in slovenia. the drava river flows through the area in question across this alluvial plain. the artificially regulated power canal of the zlatoličje hydroelectric power plant runs parallel to the river. pursuant to environmental regulations, mineral resources can be exploited in these areas only up to two metres above the highest groundwater level. this criterion makes it almost impossible to pursue the additional exploitation of mineral resources in this area, as well as similar areas in the catchment area of the danube river in slovenia. we believe that in terms of the shared use of physical space it is necessary to change this limitation and link it directly to the percentage of exploited physical space and the application of relevant extraction technologies, which do not pollute groundwater either directly or indirectly. we also believe that the criterion put in place does not withstand expert judgment as the requirement for excavation to cease up to two metres above the highest groundwater level was not defined by means of the scientific method. the article analyses inconsistencies and puts forward measures for the ongoing eco-friendly and economically sustainable exploitation of mineral resources. as an alternative, we thus suggest implementing the eu regulation via an act that would set out the necessary limitations, based on expert starting points arising from cartogra phic bases under consideration of the tetrahedral consensus-seeking methodology. the drava and ptuj plain (yellow area in figure 1), which is discussed here, falls under two geotectonic units: the smaller part to the west encompasses the east pohorje massif and belongs to the eastern alps, whereas the remaining part comprising the slovenske gorice hills, haloze hills, dravinjske gorice hills (between the dravinja river and the drava plain) and the low­ lands along the drava river belongs to the pannonian basin. the pannonian basin is formed from neogene sediments. meanwhile, the drava and ptuj plain is covered by quaternary sediments. the drava plain covers a large flat part of the štajerska re­ gion on the right (west) bank of the drava river. broadly speak­ ing it covers a triangle shaped area of 260 km2 between maribor, ptuj and pragersko. the average altitude of the plain is 250 me­ tres above sea level. to the east of the drava plain is the pohorje massif, to the north lie the slovenske gorice hills, with the haloze hills and the dravinjske gorice hills to the south. from the left (east) bank of the drava river towards ormož and ex­ tending to the east (around ptuj), the lowlands continue as the article history: manuscript received july 22, 2020 revised manuscript accepted january 13, 2021 available online february 28, 2021 keywords: mineral resources, groundwater protection, implementing the eu acquis mailto:senko.plicanic@pf.uni-lj.si mailto:zeljko.pogacnik@georudeko.si mailto:eva.koren@guest.arnes.si mailto:goran.vizintin@guest.arnes.si g eo lo gi a c ro at ic a geologia croatica 74/186 ptuj plain. the surface of the plain dips slightly from north west to south east. it should be noted that the flat part of the drava plain is not entirely flat, instead it was dissected in the pleisto­ cene and there are barely noticeable holocene river terraces (žlebnik, 1982). the ptuj plain is a plain between ptuj and ormož, which makes up, together with the drava plain, the lar­ gest flat area in north eastern slovenia. the divide between the plains is formed by the drava river (near ptuj). the ptuj plain transitions into the pesniška dolina valley to the north where it is enclosed by the slovenske gorice hills, and to the south by the haloze hills. the power canal of the formin hydroelectric power plant runs parallel to the drava river. other water courses in the plain are the pesnica and zvirenčina rivers and the sejanski po­ tok stream. the average altitude is 215 metres. the pre­neogene basement is composed of rocks of the east­ ern alps that crop out on the western edge of this geotectonic unit. neogene strata comprise miocene and pliocene sediments (figure 2). miocene sediments begin with helvetic (mioč & figure 1. important alluvial plains in the republic of slovenia. red marks the alluvial area where extraction is virtually impossible, yellow marks areas where extraction is heavily affected by legislation, green marks areas that have very deep groundwater, and the blue area marks the alluvial plain that is not relevant with regard to mineral resources. figure 2. study area shown on google earth based on the basic geological map of the maribor and leibnitz sheets at a scale of 1:100,000 (žnidarčič & mioč, 1987); below: groundwater height in the drava and ptuj plain. g eologia c roatica pličanič et al.: natural resources self-sufficiency – how to balance groundwater protection and mineral resources exploitation – pleterje case ... 87 žnidarčič, 1987) nowdays classified as ottnangian–karpa­ tian conglomerate, sandstone and sandy marl. these are overlain by badenian gravel, conglomerate, sand, marl and lithothamnion limestone covered by sarmatian layers of gravel, sand and sandy marl, followed by pannonian marl, sand and gravel. pliocene sed­ iments are coarser grained when compared to miocene sedi­ ments. gravel (sometimes loosely consolidated into conglomer­ ates) and sand prevail, while clay lenses and layers of clayey marl occur less frequently. quaternary sediments are represented by various deposits in the drava and ptuj plain: marsh sediments (silt and clay), gravel, sandy clay and alluvial, diluvial and prolu­ vial materials along the perimeter of the plain. plio–quaternary sediments such as gravel, clayey gravel, sand, and clay stretch along the western and southern edge of the drava plain. most of the gravel (up to 70 wt%) is deposited in river terraces that can reach up to 30 metres in height. the sand and sandy clay propor­ tion is 20 wt% and 10 wt%, respectively. an average sample of sandy gravel contains less than 50 wt% of sedimentary rock (pri­ marily limestone and dolomite, and lesser amounts of sandstone and chert), followed by metamorphic rocks (primarily gneiss and quartzite, with lesser amounts of mica, phyllite and amphibolite), whereas igneous rocks make up the lowest proportion (mostly granite, rhyolite, diorite, gabbro, trachyte and keratophyre). based on the hydrometeorological data (ogrin, 1996), the drava and ptuj plain falls under the moderately continental cli­ mate of eastern slovenia (sub­pannonian climate), where april averages are higher or approximately equal to october averages. the average annual precipitation is between 800 to 1000 mm and is therefore classified as a subcontinental precipitation regime. eastern and north eastern slovenia feature several locations of deposits of industrial and energy mineral resources, as well as sites of crushed stone resources, primarily gravel deposits (pits) (table 1). the state sets out in its overarching strategy paper (national mining strategy – mineral resource management, october 2018: original title: državna rudarska strategija – gospodarjenje z min­ eralnimi surovinami, oktober 2018), referred to here as “the na­ tional mining strategy”), under which it manages the natural re­ source, that the slovenian development strategy 2030 also seeks to establish a self­sufficiency dynamic (dubiński, 2013) and en­ sure the country’s independence from foreign mineral resources. this could be achieved considering the availability of natural re­ sources of economic value, the social acceptability of such exploi­ tation, and the minimisation of environmental influences. the available reserves of mineral resources (gravel and sand) ensure short­term self­sufficiency with mineral resources from the existing gravel pits and sand pits. considering the average consumption of the past 20 years, (2,705·106 metric tonnes per annum), these reserves will provide for 11 years of balanced ex­ traction of resources taking into account the available average reserves as of 2016. however, it is absolutely necessary to con­ sider how to ensure that, going forward, there will be sufficient resources available, whilst taking into consideration mining op­ erations, their economic efficiency (especially with variable ex­ penses per unit of resource associated with non­mining pro­ cesses; kudełko et al., 2013; henckens et al., 2016), and the limitations arising from the problems (voulvoulis et al., 2017) related to implementing this piece of legislation, with which the concessionaires are bound to comply. in the drava and ptuj plain, the remaining alluvial plain ex­ traction from sand pits takes place with hydraulic excavators, loaders und bulldozers (figure 3). typically, the extraction of mineral resources requires the prior deforestation of the area, clearing of undergrowth, and the stripping of the upper humus/ soil cover (from 0.3 m to 0.5 m thick) from the surface of the en­ tire extraction area. pedologic horizons b and c comprise a 0.5 m to 0.7 m thick layer of clayey gravel which counts as tailings in the technological process. humus and tailings are stored to the side of the extraction area in a heap (in line with the applicable mining project) and are then used for the rehabilitation and recul­ tivation of parts of the mineral resource exploration site (železnikar, 2015). table 1. tabular and graphical overview of production and reserves (in metric tonnes) of mineral resources gravel and sand for the construction industry in slovenia (senegačnik et al, 2019). 1988 1993 1998 2003 2008 2013 2016 2017 2018 production 3,455,355 2,668,860 2,440,115 3,437,911 4,506,076 2,143,013 1,833,732 2,047,403 1,810,666 reserves 63,227,742 39,080,471 18,019,921 34,241,209 46,148,792 34,904,839 29,927,107 30,535,719 28,976,748 g eo lo gi a c ro at ic a geologia croatica 74/188 we consider the concern regarding open water surfaces and the evaporation rate, which such surfaces increase, to be a pre­ requisite for sustainable development. nevertheless, restrictively set criteria that allow differing interpretations of the legislation do not support commercially agile mining operations and, by ex­ tension, fail to support self­sufficiency with regard to mineral re­ sources. namely, article 8 of the decree on the river basin manage­ ment plan for the danube basin and the adriatic sea basin (of­ ficial gazette of rs, no. 61/11, 49/12 and 67/16) specifically lays down the bans, conditions and limitations concerning groundwa­ ter usage, and the conditions for groundwater disturbances. six paragraphs outline the conditions for groundwater usage, and two paragraphs document the conditions for exploitation of mineral substances (relating to water). thus, in paragraph six, the decree sets out that if the mining right for the exploitation of primary mineral resources pertains to groundwater, it shall be granted under the following conditions: a. exercising of the mining right shall not open or increase the aquatic surface of groundwater, b. the maximum depth of excavation must lie at least two metres above the highest groundwater level. paragraph seven of the same article decrees that mining ac­ tivities shall involve only those substances, including explosives, which on their own, or their degradation products, shall not cause deterioration of the groundwater chemistry at the site of uptake. it arises from article 4 of the mining act (hereinafter: zrud­ 1), which defines mineral resources as an asset owned by the re­ public of slovenia as a natural resource, that primary mineral resources include energy, metallic, non­metallic and other mine­ ral resources. non­metallic mineral resources comprise: 1. mineral resources for the processing industry, including quartz and quartz sand; 2. mineral resources for construction materials and product industries; mineral resources for the construction industry including crushed stone (limestone, dolomite), all igneous and metamorphic rocks, and gravel, rubble and sand. the decree, zrud­1 and the water act (hereinafter: zv­1) fail to make clear when the mining right for the exploitation of mineral resources applies to groundwater. we believe that this provision of the decree is to be interpreted as meaning that the mining right for exploitation applies to groundwater only where the exercise of the mining right for exploitation of mineral re­ sources, i.e. mining (exploitation of mineral resources), impacts groundwater. as previously stated, the decree specifies in article 8 the bans, conditions and limitations on groundwater usage and conditions concerning groundwater disturbances. thus, the main objective of article 8 of the decree is to protect groundwater against pollution, also in cases when pollution might be brought about due to mining operations (exploitation of mineral re­ sources). for the legal analysis of applicable regulations concerning the issue at hand it is important to look at directive 2006/118/ec on the protection of groundwater against pollution and deteriora­ tion. the key is to determine whether the restrictions defined by the decree are enshrined in this directive. directive 2006/118/ec on the protection of groundwater against pollution and deteriora­ tion, which was adopted by the european parliament and the figure 3. excavation with hydraulic excavator (a); excavation and loading with loader (b) and excavation with bulldozer and loader (c). g eologia c roatica pličanič et al.: natural resources self-sufficiency – how to balance groundwater protection and mineral resources exploitation – pleterje case ... 89 council of the european union back in 2006 (hereinafter: the directive), establishes specific measures for the prevention and control of groundwater pollution, namely: • criteria for the assessment of good groundwater chemical status; • criteria for the identification and reversal of significant and sustained upward pollution trends and for the definition of starting points for trend reversals. this directive also complements the provisions preventing or limiting inputs of pollutants into groundwater already con­ tained in directive 2000/60/ec, which establishes a framework for community action in the field of water policy (the water framework directive – wfd), and aims to prevent the deteriora­ tion of the status of all bodies of groundwater. the directive 2000/60/ec establishes in this regard that member states shall implement the measures necessary to prevent or limit the input of pollutants into groundwater and to prevent the deterioration of the status of all bodies of groundwater. the directive does not contain any provision that would directly impose conditions for the exploitation of mineral resources with the aim of protecting groundwater against pollution. as part of the essential measures above, the directive is clear that it is up to the member states to establish how the measures are to be implemented. hence, the directive does not establish that it is necessary, in order to pro­ tect groundwater against pollution, to limit the base of excavation to a minimum of two metres above the highest groundwater level. by establishing (in the provisions of paragraph six of article 8 of the decree), that the mining right for the exploitation of pri­ mary mineral resources as it relates to groundwater may only be granted if exercising the mining right does not open or increase the water surface and groundwater, and that the excavation bot­ tom must be two metres above the highest groundwater level at a minimum, the government of the rs (hereinafter: the govern­ ment) defines that this is one of the (urgent) measures in order to prevent or limit the input of pollutants into groundwater and in order to prevent the deterioration of the status of all bodies of groundwater in slovenia. limiting the exploitation of mineral resources defined by the decree, therefore, is not a requirement set out by the relevant di­ rective. whether such limitations are compliant with the act on the government of the republic of slovenia, the water act, and the constitution, and how the arrangement in the decree affects the existing concessionaires are analysed below. the paper also analyses the constitutionality and legality of exploitation limitations as set out by the decree and their impact on self­sufficiency and proposes solutions for not only ground­ water protection but also the exploitation of mineral resources, and thus self­sufficiency. as pettersson and others show (petterson et al., 2015) in some other eu countries (sweden and finland) the environ­ mental aspects of mineral resource exploitation (the impact of mining operations on the groundwater included) are being as­ sessed through environmental impact assessment procedures (eia) on the case by case basis. this paper proposes that the same approach is also used in slovenia. 2. material and methods the manner in which the above measures, which aim to prevent or limit the input of pollutants into groundwater, and prevent the deterioration of the status of all bodies of groundwater, are to be carried out therefore falls entirely under the competence of the member states, including slovenia. slovenia implemented the requirements of this directive in various ways, for example by adopting a relevant decree, thus also with the provision under paragraph six, article 8 of the decree. this study focuses on the drava and ptuj plain as the decree strongly affects future concessions concerning the extraction of mineral resources in this particular area. it should be noted that the same implementation in an area with a similar hydrogeolo­ gical status would lead to the same issues that arise in the drava and ptuj plain. to prove the uneven depth of groundwater present, figure 4. interpretation of groundwater level measurements. g eo lo gi a c ro at ic a geologia croatica 74/190 we applied the data from exploration wells – piezometer meas­ urements and pumping tests. the drava and ptuj plain has been subject to numerous hy­ drogeological tests conducted in the f luvioglacial aquifer (breznik & žlebnik, 1961; žlebnik, 1982; supovec, 2004; tancar et al 2009 a, b; čenčur et al., 2013; vukelić & vulić, 2014). the layers of the quaternary fill are highly per­ meable for water. the coefficient of permeability of the pleisto­ cene sandy gravel fill in the drava plain ranges in various loca­ tions from 3.6 x 10­5 m/s to 8 x 10­2 m/s. the general direction of the groundwater flow (figure 4 or 5) is based on the measurement of groundwater levels (brilly & vižintin, 2011) for water resource management purposes (brilly & vižintin, 2011). there are two different approaches involved, the first one (figure 4) relies solely on interpolation, and the second one (figure 5) is a result of modelling. groundwater flow runs from west/north­west towards east/ south­east. the area is recharged by rainfall from the hilly out­ skirts of the pohorje massif and the haloze hills. based on these measurements it is possible to determine the fluctuation of the thickness of the unsaturated zone from a few metres to a little over 10 metres. similarly, the mathematical model (čenčur et al, 2013) indicates that lateral recharge occurs mostly from the west/north­west, i.e. the pohorje massif, and in lesser quantities from the south, i.e. the haloze hills. the study area is also sub­ ject to recharge from rainfall (figure 4 and 5). to create the model used to test the proportionality principle, we used visual modflow 2011.1, version 4.6.0.161, which applies the modflow (usgs) numerical groundwater flow model. the numerical model is based on solving the partial­differential equa­ tion of flow through a porous medium by using a finite­difference method. the entire plain was divided into a rectangular grid con­ taining 500 x 500 cells (91 m x 62.6 m). on the western and south­ ern outskirts of the drava plain we set recharge boundaries that are equivalent to neumann’s boundary condition. the starting value was set at 20,000 mm/m2 for each of them. the model cal­ ibration process is depicted on the flowchart in figure 6. in accord with figure 6, the model was calibrated using a tool referred to as pest. to achieve the required calibration, the model was run hundreds of times. in cases in which pest im­ provements did not generate the condition norm rms < 5%, we changed the model inflow areas and the k areas in the model. pest is a programme that is used for automatic model calibra­ tion and runs on the principle of considering certain areas in which it changes the values of selected physical parameters (in our case we chose hydraulic conductivity) set by the modeller. throughout the optimisation, the programme monitors model­ to­measurement residuals. the step involving a change is deter­ mined based on the model stability analysis which is either per­ formed beforehand by pest or determined by the user. typically, pest requires hundreds or thousands of mathematical model runs for which it tracks the residual changes. the combination of figure 5. modelled groundwater levels and recharge areas from the outskirts of the drava and ptuj plain. g eologia c roatica pličanič et al.: natural resources self-sufficiency – how to balance groundwater protection and mineral resources exploitation – pleterje case ... 91 relevant values of fluctuating parameters which will generate the best match of model­to­measurement piezometrics is generated at the end of the process as the calibration result. during calibra­ tion, the user can exclude specific values from the calibration and assign other values which the user deems to be correct. in the drava and ptuj plain the model was calibrated both with pest and manually; occasionally some parameters that were left un­ changed in pest were later changed during manual calibration in order to generate better results. the normalised root mean squared (norm rms) is the rms divided by the maximum difference in the observed head values. the normalised rms is expressed as a percentage and is a more representative measure of the fit than the standard rms, as it accounts for the scale of the potential range of data values. for example, an rms value of 1.5 will indicate poor calibration for a model with a range of observed values between 10 and 20, but it will indicate an excellent calibration for a model with a range of observed values between 100 and 200. however, the normalised rms value for the first model would be 15%, while the normalised rms for the second model would be 1.5%. in the second situation, the normalised rms values clearly indicate that the second model provides a good fit between the calculated and observed values (waterloo hydrogeologic, 2011). 3. results and discussion having started out with a model that initially featured three areas of hydraulic conductivity, the final model had 26 areas of hydrau­ lic conductivity (figure 7) for which we were able to change the values of k (figure 7) by using pest or manually, considering the restrictions of the pumping tests. it can be observed that the two methods of interpretation pro­ duce markedly different values for the same hydrological status figure 6. flowchart depicting the model calibration process for groundwater flow in the drava and ptuj plain (čenčur et al., 2013). figure 7. areas with varied hydraulic conductivity. the values range from 3.6 x 10-5 m/s to 8 x 10-2 m/s. g eo lo gi a c ro at ic a geologia croatica 74/192 (figures 4 and 5). the interpolation method plots water levels without considering different physical groundwater flow parame­ ters (figure 4), whereas these parameters are considered in the mathematically modular method (figure 5). the different methodologies (figure 4 and 5) result in differ­ ent groundwater level assessments and this issue of methodology must be appropriately addressed in the legislation, which is, as shown below are inadequately formulated and thereby impede groundwater protection, and reasonable land disturbances. the government established (with full autonomy) in the pro­ visions of paragraph six of article 8 of the decree – by establish­ ing that the mining rights for the exploitation of primary mineral resources as it relates to groundwater may only be granted if ex­ ercising the mining rights do not open or increase the water sur­ face and groundwater, and that the excavation base must be a minimum of two metres above the highest groundwater level. this is one of the (urgent) measures in order to prevent or limit the input of pollutants into groundwater and in order to prevent the deterioration of the status of all bodies of groundwater in slo­ venia. the limitations concerning exploitation of mineral resources as defined by the decree, and established above, are not a require­ ment that would arise from the said directive. whether these limi­ tations are in compliance with the government of the republic of slovenia act, the water act and the constitution are analysed below. i. the decree is a regulation enacted by the government in which it laid down the water management plan for the danube basin and the adriatic sea basin. pursuant to provisions 54 to 61 of the water act, the state manages waters by following a national water management pro­ gramme and plans were designed for the water management for both river basins. having regard to the provisions of article 55 of zv­1, the water management plan, inter alia, includes stipulating the pos­ sible types of use of water and marine assets, including a deter­ mination of conditions for or restrictions on use and other en­ croachments on water or marine assets. zv­1 defines natural and artificial public water assets as wa­ ter and marine assets. in this context, natural public water assets are inland waters (inland waters means all standing or flowing water on the surface of the land, and all groundwater on the land­ ward side of the baseline from which the breadth of territorial waters is measured), and (their) water land. artificial public wa­ ter assets are water land which is formed as a result of the reloca­ tion or regulation of a natural watercourse, the damming of run­ ning waters, the extraction or exploitation of mineral resources, or a similar type of encroachment in physical space which can be intended for general use. with this provision, zv­1 thereby authorises the govern­ ment to stipulate by way of the water management plan (also) the conditions or limitations for encroachment in water assets (which also includes groundwater). we believe that this provision of zv­1 must be interpreted as an authorisation given to the government to lay down in both river basins, not only the conditions and limitations for encroach­ ment on water assets which are already defined by zv­1 (among which there is no provision that pertains to the exploitation of mineral resources), but also other conditions and limitations for encroachment on water assets, as long as this is necessary to achieve the water management objectives, i.e. protection of groundwater against pollution, inter alia. the government adopted the decree based on article 55 of zv­1 and established that other such conditions and limitations of encroachment on water assets may, in line with the aforemen­ tioned provision of the decree, apply to, among other things the exploitation of mineral resources, if in the course of this (mean­ ing in the course of mining works pursuant to zrud­1) there might occur encroachments on groundwater. such conditions and limitations which may, as stated, also apply to the exploitation of mineral resources, are directly asso­ ciated with the formulation in zrud­1 that the landowner must obtain, in order to be able to exploit mineral resources located in or on the landowner’s land, a mining right for the exploitation of mineral resources. this legislation requiring a mining right for the exploitation of mineral resources (based on a concession) to be obtained, means that the manner in which property is acquired and enjoyed is set by the legislator pursuant to article 67 of the constitution, so that the economic, social, and environmental functions of the land area are preserved. the stipulation (in the decree) that the holder of the mining rights for the exploitation of mineral resources may conduct min­ ing works in such a way that the deepest excavation is at least two metres over the highest groundwater level, in our opinion regu­ lates the manner of exercising the mining right for the exploita­ tion of mineral resources. ii. in view of the provision of article 21 of the act on the gov­ ernment of the republic of slovenia, the government may gov­ ern and analyse in detail by way of an act or another regulation of the national assembly specific relationships considering the purpose and criteria arising from the act. it is only on the grounds of an explicit authorisation under the act that the government may also regulate by way of decree the manner of exercising the rights and obligations of citizens and other persons. it arises from the principle of legality concerning the opera­ tion of the executive and administrative branch of authority (the government and state administration), which is established by the constitution in article 120, that the operations of all those state bodies issuing and implementing general regulations must be legally dependent regarding substance, and may only techni­ cally supplement, analyse and describe the act through their regu­ lations. it must not in any way interfere with its substance, as in this case the legislative functions could pass to the government or the state administration. pursuant to the customary constitutional and legal practice, the principle of legality shall be weighed with particular attention to prevent executive bodies from independently laying down rights and obligations by regulating social relationships on a pri­ mary level. by the provision of article 87 of the constitution, the constitution­maker explicitly stipulated that the rights and obli­ gations of citizens and other persons, and their limitations, can be defined by the national assembly only through a relevant act. the phrase rights and obligations in the provision of article 87 involves not only rights (or obligations) from the constitution, as the provision of article 87 does not use the phrase human rights and fundamental freedoms. instead, the term rights also encom­ passes legal rights that are not directly steeped in the constitu­ tion (this also includes the right to the exploitation of mineral re­ sources). as mentioned, it is only with explicit authorisation g eologia c roatica pličanič et al.: natural resources self-sufficiency – how to balance groundwater protection and mineral resources exploitation – pleterje case ... 93 arising from the act that the government may regulate, by way of decree, the manner of implementing the rights and obligations of citizens and other persons. iii. the provision of article 55 of zv­1 (or any other provision of zv­1 or any other act) contains no explicit authorisation for the government to regulate the manner of the exercising of the min­ ing right for exploitation in the event that it should apply to groundwater (i.e. that it could impact groundwater). the said pro­ vision merely authorises the government in general to set the condition or limit the use and other encroachments on water or marine assets in both water areas by means of a water manage­ ment plan. we therefore opine that with the provision of article 8 of the decree, the government has acted in conflict with article 21 of the act on the government of the republic of slovenia, and in conflict with article 153 of the constitution from which it clearly arises that the government may regulate the manner in which the rights and obligations of citizens and other persons are exercised based only on an explicit authorisation arising from the act. this leads us to conclude that the decree is illegal and in conflict with the constitution. if no such authorisation arises from the act, the manner of exercising rights and obligations can be set out only by the act itself. in the case at hand, the principle of legality would be com­ plied with by way of an arrangement in which the act (zv­1) would outline the fundamental substantive framework for laying down the manner of exercising the mining right for the exploita­ tion of mineral resources, and the government would, based on such legal provision, stipulate a detailed manner regarding the exercising of the exploitation mining right. we also believe that provision 55 of zv­1 conflicts with ar­ ticle 153 of the constitution as it fails to stipulate any criteria, i.e. a substantive framework, for the government to consider when laying down conditions or limitations of use and other encroach­ ments on water or marine assets. as was clarified earlier, it arises from the principle of legali ty concerning the operation of the executive and administrative branch of authority, (the government and state administration), which is established by the constitution in article 120, that the legislator must stipulate, provided that the legislator authorises the government to issue an implementing regulation, clear­cut criteria and a substantial framework, based on which the govern­ ment shall issue such an implementing regulation. in doing so, the government may only technically supplement, analyse and describe the act through its regulations. it must not in any way interfere with its substance, as in this case the legislative func­ tions could pass to other state bodies. iv. as mentioned above, by making provision (in zrud­1) that the landowner must obtain mining rights for the exploitation of mineral resources in or on the land (based on a concession), the legislator determined the method of property enjoyment with the purpose of ensuring its ecological, social, and economic function in line with the provision from article 67 of the constitution. by requiring (with the decree) that the holder of the mining right may perform mining works to exploit mineral resources in a way to ensure that the deepest excavation is at least two metres above the highest groundwater surface, the government, in our opinion, regulated the mining right for exploitation of mineral resources unlawfully and in violation of the constitution. the afore­mentioned legal arrangement represents a deter­ mination of the method of property enjoyment pursuant to arti­ cle 67 of the constitution. this determination constitutes various limitations of the freedom to property, which are indispensable for ensuring the ecological, social, and economic function of the property. this, therefore, constitutes limitations to the freedom to property that are necessary in order to protect the environment and the interests of other owners. there is established constitutional case law in slovenia with regard to this issue. the legal order determines what is subject to private ownership and what are the protected property entitle­ ments by considering economic and social relationships. in that regard, the legal order must observe the purpose of the constitu­ tional guarantee of ownership, which means ensuring and imple­ menting individuals’ freedom. at the same time, property as a legal institution depends on the functions conferred by the legal order. the fact that an individual is not limited in exercising their property entitlement, but must observe the interests of other com­ munity members and the community in general, falls within the concept of ownership rights according to roman law. the constitutions of democratic countries protect the owner­ ship right as a special form of substantive protection of human freedom, which should, together with other constitutional rights, ensure the possibility of the freedom, satisfying vital needs and personal development within society. at the same time, the free­ dom of individuals with regard to ownership cannot be unlimited and linked only to one individual–the owner. instead, the exer­ cise of this right must observe the interests of other members of the community as well. these conclusions were also taken in consideration in the constitution. in general, the right to private property is provided for with article 33 of the constitution. article 67 of the consti­ tution states that the law provides for property acquisition and enjoyment in a way that ensures its economic, social, and eco­ logical function. in addition, this article includes the powers granted to the legislator to determine the content of the right of ownership within the functions of this right. therefore the provi­ sions set out in articles 33 and 67 of the constitution are inher­ ently linked, and must be observed by the legislator in providing specific expression of the content of the right to ownership. therefore, the right to ownership, provided for by article 33 of the constitution, cannot be examined without article 67 of the constitution, which addresses the economic, social, and ecolog­ ical function of property. article 67 of the constitution follows the assumption that, in addition to the individual function, prop­ erty must also have a function of serving the entire community. the right of the owner must also serve to exercise the freedom and personal development of others or the entire community. ar­ ticle 67 of the constitution allows and requires the legislator to determine the content of the property. the constitutional court’s position is that in cases where natural resources are in question, determining the method of ex­ ercising the right of ownership does not necessarily interfere with article 33 of the constitution, and that instead, such limitations fall within the social attachment of property. this means that the legislator, based on an authorisation from article 67 of the constitution, determines the content of the right to private property for single natural resources and assets g eo lo gi a c ro at ic a geologia croatica 74/194 (forests, waters, mineral resources etc.) which are protected by article 33 of the constitution. thus, determining the method of property enjoyment ac­ cording to article 67 of the constitution does not necessarily in­ terfere with the right to private property from article 33 of the constitution, although it does, to some extent, limit the indivi­ dual’s freedom in connection to property, or, in other words, it does not limit the individual’s freedom in connection to property, despite the fact that it removes certain property entitlements from the constitutional protection. however, the authorisation from article 67 of the constitu­ tion is limited. in case the legislator exceeds the limit, this is no longer considered a determination of the method of property en­ joyment; instead, it is considered an interference with the right to private property. such intervention may be allowed if it passes a rigorous constitutional review according to the so­called pro­ portionality test. in the opposite case, such intervention is not al­ lowed. the limit depends not only on the nature of the object of property, but also on the type of obligations that were imposed on the owner by the legislator in determining the method of prop­ erty enjoyment. in our opinion, any obligation set out in the process of deter­ mining the method of property enjoyment is indisputable, as long as it does not, in the implementation of one of the property func­ tions (economic, social or ecological), reduce the value of the ob­ ject or its yield for the owner. any other obligation is considered an interference with the right to private property, even if such interference is allowed. an interference with the right to private property is allowed in some cases as stated in paragraph 3 of article 15 of the con­ stitution. based on paragraph 3 of article 15 of the constitution, human rights may only be restricted in cases determined by the constitution and if they are restricted by the rights of others. ac­ cording to established constitutional case law, human rights and fundamental freedoms may be restricted if the legislator follows a constitutionally allowed objective and if such limitation is in line with the principles of the rule of law (article 2 of the con­ stitution), specifically with the principle forbidding excessive state interventions (general principle of proportionality). an assessment of the possible excessiveness of intervention is performed by the constitutional court based on the propor­ tionality test. this test includes an assessment of three aspects of the intervention: 1. is the intervention urgent (necessary) to attain the objec­ tive pursued? 2. is the intervention under assessment suitable to attain the objective pursued, meaning is it actually possible to attain this objective with the intervention? 3. is the severity of consequences of the assessed interven­ tion in the affected human right proportionate to the value of the objective pursued or the benefits that will follow (the principle of proportionality in its strict sense or the prin­ ciple of proportionality)? only if the intervention passes all three aspects of the test is it considered constitutionally allowed. when determining the method of property enjoyment, meaning determining limitations that are necessary to protect the environment and interests of other owners, especially when such limitations constitute an interference with the right to private property, the legislator (and the government, if authorised by the legislator) must observe the proportionality principle. given the regulation from the constitution and constitutional case law, we are of the opinion that the provision (in zrud­1) stat­ ing that the landowner must obtain mining rights for the exploi­ tation of mineral resources in or on the land (based on a conces­ sion) falls within the framework of determining the method of property enjoyment, which does not constitute an interference with the right to private property (article 33 of the constitution), despite limiting the individual’s freedom in connection to prop­ erty to some extent. however, the provision in the decree stating that the holder of the mining right is allowed to perform mining works to exploit mineral resources in a way to ensure that the base of any excava­ tion is at least two metres above the highest groundwater surface constitutes, in our opinion an interference with the right to pri­ vate property (article 33 of the constitution), since it imposes obligations on landowners which reduce the value or yield from the land. in addition to reducing the value or yield from the land (there were no such limitations in place before the decree was implemented which means that the owner was able to excavate significantly higher quantities of mineral substances when exer­ cising their mining rights), this obligation, considering that groundwater in the territory of pomurje flows three metres below ground, makes it effectively impossible for the customer to per­ form business operations to exploit mineral resources. furthermore, we believe that such interference with the right to private property is not allowed, since it fails in our opinion, to pass the review according to the so­called proportionality test. as mentioned before, the legislator (or the government act­ ing on the basis of an explicit authorisation in the law), is obli­ gated, in accordance with article 67 of the constitution, to define the content of the right to private property for single natural re­ sources or assets (forests, waters, mineral resources etc.). moreo­ ver, the legislator (or the government acting on the basis of an explicit authorisation in the law), is obligated, in accordance with articles 5 and 70 of the constitution, to draw acts and define terms to exploit natural assets, terms for the use of land, and terms and methods of performing business and other operations with the purpose of providing for a healthy living environment. the determination of terms applicable to the exercise of the mining right to exploit mineral resources complies with the above­mentioned constitutional provisions. this means that the government (in case there was legal basis) or the legislator (if such legal basis was defined by the legislator in zv­1) would have a constitutional basis for determining that the holder of the min­ ing right is allowed to perform mining works to exploit mineral resources in a way as to ensure that the maximum depth of exca­ vation is at least two metres above the highest groundwater sur­ face, and would thus also have a constitutionally allowed objec­ tive to interfere with the right to private property. as the next step, it must be assessed whether the limitation in question is in line with the general principle of proportiona lity. we are of the opinion that the limitation of the maximum depth of excavation to two metres above the highest groundwater surface for the entire territory of the country (the decree is valid for both the water bases, meaning for the entire territory of the country) is not an urgent action which would contribute towards attaining the objective pursued, that is, the protection of ground­ water from contamination. it is also not necessarily true that such a measure would actually contribute to attaining the objective of such limitation (meaning effective protection of groundwater from contamination). in our opinion, an assessment of the mea­ sures necessary to protect groundwater from contamination due g eologia c roatica pličanič et al.: natural resources self-sufficiency – how to balance groundwater protection and mineral resources exploitation – pleterje case ... 95 to mining works (when exercising the mining right to exploit mineral resources) should be performed separately based on the data on groundwater reserves below a particular territory (their depth). reliable and accurate data on groundwater reserves are only attainable by drilling test wells, which would reveal the ac­ tual depth of groundwater in a particular location. only once such data are available can the measures for the protection of ground­ water be assessed. moreover, suitable measures should be defined by weighing two concepts–protection of groundwater and protec­ tion of the right to private property. with regard to this, the severity of the consequences of the interference with the right to private property should be proportionate to the benefits that will follow such interference. with regard to questions on whether or not the intervention is urgent (necessary) to attain the objective pursued and whether or not the intervention under assessment is suitable to attain the objective pursued, (meaning that it is actually possible to attain this objective with the intervention), we are of the opinion that there are other more moderate measures available that do not in­ terfere with ownership rights to such an extent and would con­ tribute towards attaining the objective pursued and at the same time meet the criteria of proportionality in a more strict sense (meaning that the interference with the right to private property is proportionate to the benefits following such interference), for example: • setting the limitation of the maximum excavation depth to less than two metres (based on the data on groundwater re­ serves and other specific circumstances, retrieved on a case­by­case basis); • establishing the mandatory use of modern mining techno­ logy which prevents the risk of contamination of ground­ water while performing mining works. considering this, we believe that the decree is also in viola­ tion of the constitution because the limitation on excavation depth to at least two metres above the highest groundwater sur­ face is an interference with the ownership right, which is not al­ lowed by the constitution. in case that the legal basis for the limitations of ownership rights in question would be defined by law and by the govern­ ment implementing regulations, issued on the basis of such law, and in case that these limitations would pass the proportionality test, such interventions would be constitutionally allowed, but only if one additional condition would be met; that the landown­ ers would be entitled to receive compensation due to such inter­ ference with the right to private property. namely, if the legisla­ tor or the government with its regulations which, in determining the method of property enjoyment in accordance with article 67 of the constitution, interferes with the right to private property to the extent that it renders this right completely void (thus pre­ venting the owner from using it for their benefit) and if the owner is left with only a bare right (“nuda proprietas”), such interven­ tions should be considered as expropriating interventions. thus, if an intervention of power in the ownership right is such as to render the entitlements which constitute the ownership right com­ pletely void, such an intervention must be regarded as expropria­ tion. such expropriation intervention must not be implemented based on a regulation or other general measure, but only on a case­by­case basis according to an expropriation procedure and against payment of compensation or remuneration in kind. there are self­sufficiency possibilities (table 1 – the produc­ tion and reserves of mineral resources) that cannot be fully used due to the regulation. this is paradoxically contrary to the na­ tional environmental legislation that defines economic and finan­ cial instruments for the protection of the environment. these in­ struments are, in our opinion, significantly larger when the same unit of mineral resource requires drilling and blasting operations, transportation around raw material exploration sites (which rep­ resents up to 30% of the cost price for one unit of raw material; pogačnik, 2011), and longer transport distances from the ex­ ploration site to the user. therefore, based on the above, suitable research methods for the verification of the actual depth of groundwater presence on alluvial plains must be established before the beginning of min­ ing works which, according to the national legislation, also in­ clude research activities, the purpose of which is to determine the existence, position, and form of mineral deposits, their quality, quantity, and conditions for their exploitation. this includes the use of suitable complementary 3d geophysical techniques for groundwater detection, such as the gpr method (oliviera, 2019; uzoije et al., 2019; peterson et al., 2020; zajc & ur­ banc, 2019) or seismic electrical resistivity tomography – ert (acciano et al., 2019; chiemeke & felix, 2019; draskowitz et al., 1995; saad et al., 2012; redhaounia et al., 2015) which ensure sound results. of course, such research methods must always be referenced with specific data (mol­ lema & antonellini, 2016; voulvoulis et al., 2017), which can be retrieved from the research on existing infrastruc­ ture used to monitor the presence of groundwater level, its qua­ lity and, most importantly, management (voulvoulis et al., 2017; jovičić et al., 2009). in addition, there are a number of computer tools available to analyse data that enable production table 2. a representation of the co-decision method according to the vertical and horizontal component, including all stakeholders involved in the co-decision process of determining the location of the exploration site and its management based on environmental and spatial laws. vertical component mining act (zrud-1) environmental protection act (zvo) and its implementing regulations spatial management act (zurep) and spatial planning act (zpnačrt) considering expert suggestions and strategic documents, it indicates the location of the raw materials and suggests technical methods for their extraction. gives amended guidelines or assesses the appropriateness of performing mining works (given the applied technical methods) considering the presence of groundwater. when the works are acceptable and therefore the purpose of the land use and its consequences (changing the morphology for a more rational use of the surface of the area), only those areas are included, which allow for a safe exploitation of mineral resources and thus provide self-sufficiency to the local community. horizontal component improvement of research techniques and technological mining procedures with the purpose of obtaining data of improved quality and to reduce to a minimum the negative impact per unit of the space where works are performed to exploit natural resources. observing and managing environmental protection on the micro area of the exploration site and at local level (traceability of groundwater quality). active involvement of the local community (spatial planners and local politics) in the process of co-decision regarding the transformation and further use of the territory. g eo lo gi a c ro at ic a geologia croatica 74/196 of a more accurate cartographic basis which, in addition to those mentioned above, also include the modflow tool (izady et al., 2017). to achieve synergy in providing enough mineral resources and protecting the environment, we suggest the interdisciplinary approach provided for by the tetrahedral co­decision method (ta­ ble 2, figure 8). in the process of confirming a new extraction location as part of a detailed spatial plan process, such an ap­ proach enables the investor and other stakeholders included in area management and environmental protection to obtain an overview of the current condition, technology used, and the im­ pact of the works on a space unit where the natural resource is being extracted. 4. conclusion we accept that the protection of groundwater on an alluvial aqui­ fer is necessary and appropriate. regarding this, we shed light on issues arising from the implementation of the eu decree in the national legal system. as shown, slovenia opted for a very re­ strictive implementation that virtually disables the exploitation of mineral resources in shallow alluvial aquifers in the north east­ ern part of slovenia, which indirectly prevents self­sufficiency in natural resources (aggregate­technical stone) suitable for con­ struction use. in our opinion, the implementation raises a constitutional is­ sue due to the breach of several articles of the constitution. the implementation has been performed with a governmental decree which, in its content, expresses its position on the issue, which is not allowed by law. the decree interferes with ownership rights and limits the rights already granted, without awarding the right to compensation for the injured parties. in addition, the implementation does not provide consistent methodology records and a consistent method of establishing suf­ ficient non­protected zones above the section of the aquifer, satu­ rated with groundwater (figures 4 and 5). the content of the de­ cree is worded in a way to protect groundwater by imposing bans and causing damage to concessionaires, regardless of the impacts of single spatial interventions. such implementation fails to dis­ tinguish between various hydrogeological properties and the im­ pacts of gravel pits connected to these. the implementation should be carried out through a law defining the necessary limi­ tations set up based on expert background from cartographic bases and considering the tetrahedral method of achieving agree­ ment, which gives equal weight to selecting the location of the exploration site, environmental protection, and the performance of mining works. we are of the opinion that a systematic and expert approach should be employed to determine the maximum amount of open area, determine the technology to extract mineral resources with the minimal impact on groundwater quality, and lay down other measures aimed at maintaining groundwater levels, especially on riverbeds that in slovenia have mostly been modified by human intervention. references acciano, f., busetti, m., böhm, g., baradello, l., affatato, a., dal cin m. & nieto, d. (2019): geophysical investigation of the isonzo plain (ne italy): imaging of the dinaric­alpine chain convergence zone.– ital. j. geosci., vol. 138, 202–215. doi: 10.3301/ijg.2019.01 brilly, m. & vižintin, g. (2011): konceptualni model za dravsko ptujsko polje – bober, mejnik 2, poročilo p1b, ekspertno numerični sistem za podporo odločanju na aluvijalnih telesih podzemnih voda slovenije [the conceptual model for the drava ptujsko polje bober, milestone 2. report p1b, expert numerical system for a groundwater decision support in alluvial bodies of slovenia – in slovenian].– unpubl. report, ljubljana, 35 p. breznik, m. & žlebnik, l. (1961): geological conditions along the drava river between maribor and ptuj with special regard to the construction of water power plants. geologija, 61, 7, 146–169. chiemeke, c.c. & felix, o.o. (2019): evaluation of seismological activity and site characterization using seismic tomography.– earth science, 129, 53048–53052. čenčur, c., celarc, b., vižintin, g., brilly, m. & vidmar, a. (2013): bober ­ boljša opazovanja za boljše ekološke rešitve, izdelava modelskih oro­ dij za spremljanje suše, ocenjevanje stanja podzemnih voda in prognoziranje din­ amike morja, 3. sklop: ekspertno numerični sistem za podporo odločanju na alu­ vijalnih telesih podzemnih voda slovenije, kalibracija in validacija numeričnega modela toka podzemne vode za dravsko in ptujsko polje in izdelava poročila p3b, arso [bober ­ better observations for better ecological solutions, development of model tools for drought monitoring, assessment of groundwater status and forecasting of sea dynamics, lot 3: expert numerical system for decision support on alluvial bodies of groundwater in slovenia, calibration and validation of a numerical model for the drava and ptuj alluvial field and preparation of p3b report – in slovenian].– unpubl. report, arso, ljubljana, 150 p. draskowitz, p., magyar, b. & pattantyùs­á, m. (1995): geophysical me­ thods in groundwater prospecting and environmental protection.– fisica de la tiera, n°7, 53–86 dubiński, j. (2013): sustainable development of mining mineral resources.– journal of sustainable mining, vol. 12, no. 1, 1–6. doi: 10.7424/jsm130102 directive; official journal of the european union l 372/19, 27.12.2006. doi: 10.7424/jsm130102 henckens, m.l.c.m., van ierland e.c., driessen, p.p.j. & worrell, e. (2016): mineral resources: geological scarcity, market price trends, and future generations.– resources policy, 49, 102–111. doi: 10.1016/j.resourpol.2016.04.012 izady, a., abdalla, o., joodavi, a. & chen, m. (2017): groundwater model­ ing and sustainability of a transboundary hardrock–alluvium aquifer in north oman mountains.– water, 9, 161. doi: 10.3390/w9030161 figure 8. the tetrahedral method of achieving agreement considering the structure of the stakeholders included in the decision-making procedure. g eologia c roatica pličanič et al.: natural resources self-sufficiency – how to balance groundwater protection and mineral resources exploitation – pleterje case ... 97 jovičić, v., šušteršič, j. & vukelič, ž. (20096): the application of fibre rein­ forced shotcrete as primary support for a tunnel in flysch.– in: tunnelling and un­ derground space technology, 24/6, 723–730. kudełko, j., waniekista, k. & wirth, h. (2013): economic evaluation of mine­ ral extraction projects from fields of exploitation during operational periods.– jour­ nal of sustainable mining, vol. 12, no. 1, 41–45. doi: 10.7424/jsm130108 mioč, p. & žnidarčič, m. (1987): tolmač za lista maribor in leibniz, l 33­56 in l 33­44 [basic geological map of sfry 1:100000, geology of the maribor & leibniz sheet – in slovenian].– zvezni geološki zavod, beograd, 58 p. mollema p. n. & antonellini, m. (2016): water and (bio)chemical cycling in gravel pit lakes: a review and outlook.– earth­science reviews, 159, 247–270. doi: 10.1016/j.earscirev.2016.05.006 ogrin, d. (1996): climate types in slovenia.– geografski vestnil, 68, 39–56. oliviera, m.a. (2019): gpr stratigraphy and quaternary morphogenesis in the semi­ arid brazil.– mercator, fortaleza, v.18. doi: 10.4215/rm2018.e18027 pettersson, m., oksanen, a., mingaleva, t., petrov, v. & masloboev, v. (2015): license to mine: a comparison of the scope of the environmental as­ sessment in sweden, finland and russia.– natural resources, 6, 237–255. doi: 10.4236/nr.2015.64022 peterson, c.d., jol, h.m., percy, d. & perkins, r. (2020): use of ground penetrating radar, hydrogeochemical testing, and aquifer characterization to establish shallow groundwater supply to the rehabilitated ni­les’tun unit flood­ plain: bandon marsh, coquille estuary, oregon, usa.– journal of geography and geology, 12/1, 25–49. doi: 10.5539/jgg.v12n1p25 pogačnik, ž. (2011): recycled construction materials as supplemental raw materials for the opc clinker production in salonit anhovo.– in: žibret, g. &. šolar, s.v. (eds.): sustainable aggregates resource management: international conference, september 20­22, 2011, ljubljana, slovenia: abstract and short paper book. lju­ bljana: geological survey of slovenia, 2011, 24–25. redhaounia, b., ilondo, b.o., gabtni, h., sami, k. & bédir, m. (2015): electrical resistivity tomography (ert) applied to karst carbonate aquifers: case study from amdoun, northwestern tunisia.– pure appl. geophys. doi: 10.1007/s00024­015­1173­z saad, r., nawawi, m.n.m. & mohamad, e.t. (2012): groundwater detection in alluvium using 2­d electrical resistivity tomography (ert).– electronic jour­ nal of geotechnical engineering, vol. 17, 369–376. senegačnik, a., burger, a. & štih, j. (2019): stanje na področju mineralnih surovin v sloveniji v letu 2018 [situation in the field of mineral resources in slovenia in 2018 – in slovenian].– mineralne surovine, 15/1, 12–24. supovec, i. (2004): hidrogeološko poročilo za potrebe izdelave programa monito­ ringa podzemnih vod na območju odlagališča nenevarnih odpadkov gajke pri ptuju [hydrogeological report for the needs of the preparation of the groundwater monitoring program in the area of the non-hazardous waste landfill gajke near ptuj – in slovenian].– unpubl. report, hgem d.o.o., ljubljana, 50 p. tancar, m., supovec, i., vižintin, g. & pučko, t. (2009a): geološko, tehnično in hidrogeološko poročilo o izvedbi dveh piezometrov na lokaciji vmp dornava. [geological, technical and hydrogeological report on the implementation of two piezometers at the vmp dornava site – in slovenian].– unpubl. report, hgem d.o.o., ljubljana, 69 p. tancar, m., supovec, i. & vižintin, g. (2009b): geološko, tehnično in hidrogeološko poročilo o izvedbi dveh piezometrov na lokaciji vmp gerečja vas [geological, technical and hydrogeological report on the implementation of two piezometers at the vmp gerečja vas site – in slovenian].– unpubl. report, hgem d.o.o., ljubljana, 68 p. uzoije, a.p., chrysogonus nwaigwe, c. & bright, n. (2019): vulnerability assessment of a sand­rich alluvium; a drastic model approach.– interna­ tional journal of scientific & engineering research, vol. 10, issue 5, 1398–1428. voulvoulis, n., arpon, k.d. & giakoumis, t. (2017): the eu water frame­ work directive: from great expectations to problems with implementation.– sci­ ence of the total environment, 575, 358–366. doi: 10.1016/j.scitotenv.2016.09.228 vukelič, ž. & vulić, m. (2014): ocena in natančnost ocene 3d­položaja točk v vrtini [evaluation of 3d positions and the positional accuracy of points within a borehole – in slovenian].– geodetski vestnik: glasilo zveze geodetov slovenije, 58/2, 327–341. waterloo hydrogeologic (2011): visual modflow 2011.1 user’s manual.– waterloo hydrogeologic. retrieved 03.07.2020. zajc, m. & urbanc, j. (2019): using gpr on a problematic agricultural field for groundwater protection in a karst environment. near surface geoscience con­ ference & exhibition 2019, 8–12 september 2019, the hague, netherlands. zrud­1; mining act (official gazette of rs, no. 14/14 and 61/17 ­ gz) zv­1; the water act (official gazette of rs, no. 67/02, 2/04 – zzdri­a, 41/04 – zvo­ 1, 57/08, 57/12, 100/13, 40/14, 56/15 and 65/20). železnikar, v. (2015): mining project for obtaining a concession for exploitation with an estimate of the amount of rehabilitation costs after final exploitation.– monograph, no. 1­8 / 2014­vž, august, 62 p. žlebnik, l. (1982): hidrogeološke razmere na dravskem polju [hydrogeological conditions in the drava plain – in slovenian].– geologija, 82, 25/1, 151–164. 2020 | 73/1 | 69–84 | 11 figs. | 2 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society application and improvement of soil spatial distribution mapping using advanced modeling techniques jasminka alijagić* and robert šajn geological survey of slovenia, dimičeva ulica 14, si–1000 ljubljana, slovenia; (jasminka.alijagic@geo-zs.si; robert.sajn@geo-zs.si) *corresponding author doi: 10.4154/gc.2020.01 abstract the main purpose of this contribution is to develop realistic prediction digital soil maps in order to increase their visuality, and to evaluate and compare the performance of different modeling techniques: a) kriging, b) artificial neural network – multilayer perceptron (ann-mlp) and c) multiple polynomial regressions (mpr). the following criteria were used to determine selection of the testing site for the modeling: (1) intensive metal ore mining and metallurgical processing; (2) geomorphological natural features; (3) regular geological setting, and (4) the remaining minefields. the success of digital soil mapping and the plausibility of prediction maps increases with the availability of spatial data, the availability of computing power for processing data, the development of data-mining tools, geographical information systems (gis) and numerous applications beyond geostatistics. advanced prediction modeling techniques, ann-mlp and mpr include geospatial parameters sourced from digital elevation models (dem), land use and remote sensing, applied in combination with costly and time-consuming soil measurements, developed and finally incorporated into the models of spatial distribution in the form of 2d or 3d maps. innovative approaches to modeling assist us in the reconstruction of different processes that impact the entire study area, simultaneously. this holistic approach represents a novelty in contamination mapping and develops prediction models to help in the reconstruction of main distribution pathways, to assess the real size of the affected area as well as improving the data interpretation. article history: manuscript received november 28, 2019 revised manuscript accepted january 17, 2020 available online february 29, 2020 keywords: prediction maps, spatial distribution, soil contamination, kriging, artificial neural network – multilayer perceptron, multiple polynomial regressions, bosnia and herzegovina gies used for mass production generate an enormous quantity of mining waste which is considered hazardous due to the presence of toxic metals (singh et al., 2010; navarro et al., 2008). due to past and present mining activities, many worldwide rivers are significantly affected by multiple metal contamination (ferreira et al., 2016). metal containing particles are quite often transported over large distances by water. this can affect the alluvial sediments several hundred kilometres away from the main source of contamination (šajn et al., 2011; yi et al., 2012; zhao et al., 2013; pavlowsky et al., 2017). the soil maps can be generally understood as a graphic representation for transmitting information about the spatial distribution of soil attributes (yaalon, 1989). according to mcbratney et al. (2003), traditional soil mapping techniques mostly depend on ground-based surveys but they rarely inform us about the spatial distribution of soil properties at the desired resolution over the landscape. complex interactions between the soil and geospatial parameters of site factors sourced from digital elevation models (dem) is crucial for understanding the main spatial distribution pathways. their mutual coherence can be integrated by modeling techniques with an advanced prediction (alijagić, 2013). environmental surveys are usually based on sampling on the relatively small and quite well-delimited system, but in general, the measurements represent a continuum in space from which the sample has been drawn (oliver & webster, 2014). a great potential for improving predictive soil mapping (psm) techniques and understanding the relationships between soils and the environment, has been created after the increase in computer efficiency and capacity, geo-information technology, data availabi1. introduction the soil can be characterised as a natural purifying agent and a place where pollutants sink and/or accumulate. metals occur in rocks and in soils whether in the soil solution, organically bound, bound to hydrous oxides of fe, mn and al, exchangeable, acidsoluble (bound to carbonates, phosphates, etc.) or structurally bound in the residual fraction (kabata-pendias & pendias, 2001). when the metal retention capacity of the soils is exceeded (romić, 2012) and when soil conditions are changed (e.g. reaction kinetics, ph and eh values, organic matter content, microorganisms, etc.), simple ions can be released into solution, become mobile and thus accessible to plants (kabata-pendias & pendias, 2001). sources of trace elements in groundwater can be natural, (originating from earth materials), or the elements can be introduced by industrial activities, landfill, mining and transportation (bradl, 2005). important sources of trace metals input into the soils are from the metals industry. starting from mining and milling operations, concentrating, sintering and metal ore transportation to the disposal of tailings. smelting processes can include atmospheric discharges, blown dust and cause acidification of water bodies (dudka & adriano, 1997). it is known that the majority of ore minerals accommodate various other trace metals as minor inclusions, causing contamination with major and minor ore metals in areas surrounding mines and smelters (shallari et al., 1998; chopin & alloway, 2007; al-khashman & shawabkeh, 2009). the metal ore mining and processing are some of the largest releases of trace elements causing a considerable impact on the surrounding environment. obsolete metal production technolog eo lo gi a c ro at ic a geologia croatica 73/170 lity and demand for accurate and reliable maps (mcbratney et al., 2003; scull et al., 2003; bagheri bodaghabadi et al., 2015; zhang et al., 2017). it requires the creation of spatial soil information based on numerical models, which account for spatial and temporal variations in soil properties on the basis of soil information and related environmental variables (lagacherie & mcbratney, 2007). the main purpose of this study was to develop a visualisation model of contamination using linear and nonlinear mathematical methods that combine a sparse chemical analysis and various geospatial parameters in stavnja valley (bosnia and herzegovina) but at the same time to evaluate and compare the performance of different modeling techniques: kriging, artificial neural network – multilayer perceptron (ann-mlp) and multiple polynomial regressions (mpr). for this reason, five specific purposes of the present study were (1) to include various geospatial parameters in linear and nonlinear modeling; (2) to identify the main distribution pathways and change in concentrations according to the distance from the source of contamination; (3) model verification; (4) to assess the real size of the affected area, and (5) to provide an optimal methodology for geochemical researchers in areas with restricted sampling conditions. 2. materials and methods 2.1. description of the study area the river stavnja has a length of about 35 km, located in central bosnia and herzegovina, north of the capital sarajevo (fig. 1). approximately 30,000 people inhabit this valley, mostly settled figure 1. location of the study area. g eologia c roatica alijagić and šajn: application and improvement of soil spatial distribution mapping using advanced modeling techniques 71 into the small cities of vareš and breza. the stavnja river catchment has been known for intensive mining and metallurgic activities for more than 100 years. besides these activities, the valley was selected for study due to several other reasons: its unique geological setting – especially the metallogenic belt, the geomorphological characteristics that affect the contamination halo and remaining minefields from the last war, 1992-1995. the anthropogenic impact in the municipality of vareš can be reflected through the three abandoned iron ore deposits (smreka, brezik and droškovec), an abandoned pb-zn-ba deposit of veovača, the abandoned ironwork at vareš, and brown coal mining in the southern part of the study area. high concentrations of particular elements are released into the environment not only by anthropogenic activities but also by natural erosion and weathering reactions of the parental rocks that add to the complexity of the environmental assessment (alijagić, 2013). problems of contamination along the river can be demonstrated as the anisotropic appearance between the layered (isotropic) lithological units, which can be solved using advanced linear and nonlinear modeling techniques instead of a denser sampling grid which is restricted by the remaining minefields at 5-6 % of the study area. the physiography of the region displays great variability. contrasting landscapes are observed from the mountain environment in the northern part of the study with an altitude of more than 1000 m, to the southern part at approximately 400 m (fig. 2). 2.2. geological description of the study area the outcropping stratigraphic sequence exposes rock formations spanning the triassic to the cretaceous, and more recent times. ten major lithological units (fig. 3) had been isolated, ranging from the oldest to the youngest in a n-s direction. the most important geotectonic unit of the vareš metallogenic district belongs to the central ophiolite zone. vareš, siderite–haematite sedi mentary exhalative (sedex) deposits at smreka, droškovac and brezik are the locus typicus of mineralisation of the midtriassic. the deposits contain hydrothermal, stratiform siderite– haematite–chert beds. the mineralisation forms part of the anisian and ladinian sequences and displays distinct vertical zoning, reflecting a gradual change of redox conditions in the depositional environment. the veovača pb, zn, ba deposit contains ore breccia or ore conglomerates with dm to m sized clasts cemented by barite and pb–zn sulphides. the barite from veovača is typical for triassic sedex deposits elsewhere in the dinarides (palinkaš et al., 2008). 2.3. sampling, sample preparation and chemical analyses regarding the primary purpose of research, previous experience (šajn, 2005, 2006; alijagić, 2008; alijagić & šajn, 2006, 2010; stafilov et al., 2008a, 2008b), and some sampling difficulties (narrow gorge, inaccessible terrain and remained minefields), resulted in preparation of a sampling grid so that the soil profiles were raised transverse to the river flow (fig. 4). respectfigure 2. land use map. figure 3. isolated lithological units. g eo lo gi a c ro at ic a geologia croatica 73/172 ing the changes of environmental chemism according to the distance from the source of contamination, a change in altitude, and a transport mode, but at the same time understanding better the geogenic and anthropogenic influence on the level of trace element changes, the entire survey area was covered with 12 profile lines set to cross the river flow. some additional samples had been collected at the edges of the study area and some lithological units that were not covered by the profile lines. in the urban and industrial zones, the sampling grid is slightly more dense (fig. 4). the total number of soil sampling sites is 111 but at each site, samples were collected from two depths: in the topsoil (0 5 cm) and subsoil (20 30 cm) respectively. initially, the samples were air-dried and subsequently dried in a fan drier at 40 °c. all samples were analysed in the acme, ltd. laboratory in vancouver, canada (acme labs, 2010, 2011). determination of 36 chemical elements (ag, al, as, au, b, ba, bi, ca, cd, co, cr, cu, fe, ga, hg, k, la, mg, mn, mo, na, ni, p, pb, s, sb, sc, se, sr, th, ti, tl, u, v, w and zn) was performed by inductively coupled plasma mass spectrometry (icp-ms) after aqua regia digestion, during which we assisted with the results for precision and trueness based on alijagić (2013). 3. data acquisition and data processing all data processing and calculations, geostatistical data interpretation and visualization (mapping) have been performed using the following software: statistica (stat soft inc., 2012), autodesk map 3d (autodesk inc., 2012), arcinfo (esri inc., 2004) and surfer (golden software inc., 2012). in recent years, geographical information systems (gis) have been used for spatial data management and manipulation. for this purpose various spatial data were acquired by digitalization of existing topographic maps: (1) vareš 4 (475-4) in scale 1:50,000; vareš 4-1 (475-4-1); (2) vareš 4-2 (475-4-2), vareš 4-3 (475-4-3), vareš 4-4 (475-4-4), sarajevo 2-2 (525-2-2), sarajevo 2-1 (525-2-1) in scale 1:25,000 (provided by the geodetic survey of bosnia and herzegovina); (3) google earth maps (google inc., 2010); (4) maps breza-vareš, scale 1:50,000; (5) breza-podlugovi, brgule, karaule, in scale 1:10,000 (provided by bh mine action centre, in sarajevo); (6) geological maps vareš (l 34-133) and sarajevo (k 34-1) in scale 1:100,000 (provided by geological survey of slovenia and geological survey federation of bosnia and herzegovina); (7) 80 m srtm digital elevation model (cgiar consortium for spatial information, 2011); (8) 30 m aster digital elevation model (u.s. geological survey, 2011a) and (9) landsat multispectral satellite images – 7 bands (u.s. geological survey 2011b). all the aforementioned maps were used to obtain as much geospatial data as possible to be included in the database. the database includes the following information for 222 samples: identification number, sample label, sampling material, land use units, lithological units, defined zones, latitude, longitude, absolute distance from the ironworks chimneys (iron open pits, smre ka and brezik; ironworks vareš, breza coal mine) (fig. 5a), elliptical distance from the ironworks chimneys (fig. 5b), distance from the river stavnja (fig. 5c), altitude (fig. 6a), altitude above the stavnja valley bottom (fig. 6b), terrain slope (fig. 6c), aspect, plan curvature (fig. 7a), profile curvature (fig. 7b), tangent curvature (fig. 7c), and landsat spectral bands 1 7 (table 1, fig. 8). beside the aforementioned geospatial data and multispectral image bands, this database includes the analytical data (26 selected elements: ag, al, as, ba, bi, cd, co, cr, cu, fe, ga, hg, la, mg, mn, mo, ni, pb, sb, sc, th, ti, tl, v, w and zn). these elements represent mostly athropogenically entered into environment (pb-zn-hg-cd-cu-bi-ag-sb-mo-w-mn-bafe-ti) or they are mainly influenced by heterogeneous lithology (ni-cr-co-mg-th-la-as-sc-al-ti-v-ga) which content is determined by the parent material and soil properties (alijagić et al., 2015). for modeling of the spatial distribution of a group of elements with artificial neural network and multiple polynomial regression, a recall grid was used. this means that the whole study area was divided into 50 x 50 m grid cells. the total number of recall points is 41,471. this database includes only geospatial data and the landsat multispectral image bands mentioned before. 3.1. topographic and geological data the maps are constructed with the limitation of representing 3d real-world objects into a 2d representation, which involves some distortion of the shape, area, distance and direction of the spatial objects. since the topographic maps (scale 1:25,000 and 1:50,000) were ambulated in the late ̀ 70s, to get more realistic spatial data, the maps from google earth and multispectral satellite images were combined with them. particular land-use units are digifigure 4. sampling sites with determined zones. g eologia c roatica alijagić and šajn: application and improvement of soil spatial distribution mapping using advanced modeling techniques 73 talized and isolated directly from google earth in the form of kml files. such maps have been georeferenced, which means that we defined their existence in physical space, establishing locations in terms of map projections or a coordinate system. according to hill (2006), the term is used both when establishing the relationship between raster or vector images and coordinates, and when determining the spatial location of other geographical features. this procedure is thus imperative to data modeling in the field of gis and other cartographic methods. when data from different sources needs to be combined and then used in a gis application, it becomes essential to have a common referencing system. different maps may use different projection systems. georeferencing tools contain methods to combine and overlay these maps with minimum distortion. beside the topographic maps, the basic geological map (scale 1:100,000) has also been digitalized and vectored. isolation of the major lithological units is also an important step for the determination of the natural and anthropogenic background. the maps (1:25,000 and 1:10,000) of the remaining minefields and possible minefields were obtained from the bh mine action centre, in sarajevo. data about the minefields were isolated from them and incorporated into the previously digitalized topographic maps. the given data were presented into three different projection systems: topographic, geological and minefield maps in the gauss kruger projection (zone 6) with a hermanns-kogel datum; the google earth and astar in unprojected lat/long projection with a world geodetic system 1984 (wgs84) datum; and satellite images in the universal transverse mercator (utm 34n) projection with a wgs84 datum. all the aforementioned data have been converted into one projection system i.e. gauss krüger. 3.2. dem and terrain modeling (geomorphometry) a digital elevation model (dem) is a quantitative representation of the earth’s surface providing basic information about the terrain relief (guth, 2006). a dem is an important tool for geomorphometry, as its derived attributes (such as slope, aspect, drainage area and network, curvature, topographic index, etc.) are important parameters for information extraction or assessfigure 5. a – absolute distance from the ironworks chimneys; b –elliptical distance from the ironworks chimneys (ratio 1/5); c – distance from the river stavnja. g eo lo gi a c ro at ic a geologia croatica 73/174 ment of any process using terrain analysis (wolock & price, 1994). providing all these geomorphometrical data, a dem is prerequisite in different applications such as water flow modeling (jain & singh, 2003), volcanic hazards (vassilopouloua et al., 2002), terrain visualization and mapping (spark & williams, 1996), flood simulation and management (ramlal & baban, 2008, honghai & altinakar, 2011), climate and meteorological studies (thornton et al., 1997), etc. the outcomes of the models depend on the accuracy of the dem (zhang & montgomery, 1994; mukherjee et al., 2013). the accuracy of a dem is especially important when used for the spatial prediction of soil attributes, as differences in topography play a crucial role in the distribution of pedological relationships (thompson et al., 2001). like all models, dems contain a certain degree of error. errors in dem datasets are usually related to (1) data errors, (2) measurement errors and (3) processing errors (burrough, 1986; wise, 1998; wechsler, 2003). they can also be characterised as gross errors, systematic errors and random errors. the main question to be answered here is to which level of significance do certain errors extend (fisher & tate, 2006)? figure 5 provides the following geospatial information: (a) a cyclic distance from the vareš ironwork (the main source of contamination); (b) an elliptical distance from the vareš ironworks; and (c) the distance from stavnja. these three distance shapes are prepared at a scale of 1:5. the cyclic and elliptical distances have been calculated from the ironworks chimney. for easier understanding, each distance is represented by a different colour in seven equal percentile classes. several pieces of morphological spatial information: (a) an altitude; (b) an altitude above the bottom of the stavnja valley, and (c) a slope, are provided in fig. 6. terrain aspect calculates the downhill direction of the steepest slope (i.e. the dip direction) at each grid node, with values eported as azimuths. the dip direction is perpendicular to the contour lines on the surface and is exactly opposite the uphill gradient direction. terrain slope is reported in degrees from zero (horizontal) to 90 (vertical). it is based on the direction of the figure 6. a – altitude above sea level (absolute); b – altitude above the bottom of the stavnja river valley (relative); c – terrain slope. g eologia c roatica alijagić and šajn: application and improvement of soil spatial distribution mapping using advanced modeling techniques 75 steepest descent or ascent at that point (terrain aspect). this means that for a particular point on the surface the gradient direction can change. plan curvature calculates the curvature of the surface in the horizontal plane or the curvature of the contour. negative values indicate divergent water flow over the surface, and positive values indicate convergent flow. profile curvature measures the curvature of the surface in the direction of the gradient. it determines the downhill or uphill rate of change in the slope in the gradient direction (opposite of slope aspect direction) at each grid node. grid files of profile curvature produce contour maps that show isolines of a constant rate of change of the steepest slope across the surface. negative values are convex upward and indicate the accelerated flow of water over the surface. positive values are concave upward and indicate slowed flow over the surface. tangential curvature measures curvature in relation to a vertical plane perpendicular to the gradient direction, or tangential to the contour. the negative and positive areas are the same as for plan curvature, but the curvature values are different. tangential curvature measures the curvature of the surface in the vertical plane perpendicular to the gradient direction. the mathematical definitions, the general review of the methods, and applications of topographic analysis (terrain slope, terrain aspect, plan curvature, profile curvature and tangential curvature) were taken from mitasova & hofierka (1993) and moor et al. (1993). 3.3. satellite images since 1972, landsat satellites have continuously acquired spacebased images of the earth’s land surface, coastal shallows, and coral reefs and have since provided worldwide science and resource management communities with an archive of space-based land remotely sensed data – a valuable resource for people who need this data for their work (u.s. geological survey, 2011c). landsats 5 and 7 each complete approximately 14 full orbits of the earth each day. while each satellite has a 16-day full earth coverage cycle, their orbits are offset to allow 8-day repeat covera ge figure 7. a – plan terrain curvature, b – profile terrain curvature, c – tangent terrain curvature g eo lo gi a c ro at ic a geologia croatica 73/176 of any landsat scene area on the globe. landsat 7 carries the enhanced thematic mapper plus (etm+), with 30-metre visible, near-ir, and shortwave infrared bands, a 60-metre spatial resolution thermal band, and a 15-metre panchromatic band (table 1). moreover, since 2008 the usgs has freely provided all archived landsat images, along with newly acquired landsat 7 (launched in 1999) etm+ slc-off and landsat 5 (launched in 1984). tm images with less than 40 % cloud cover, thereby enabling free access to multiple images of the same sectors. it depends what you need as there are many landsat data formats: geotiff, mtl, gcp, wo) (u.s. geological survey, 2011c). in order to evaluate the capability of mapping contaminated areas from both landsat tm and etm data, we processed and analysed two available images for the study area (187 paths and figure 8. relative intensity of radiation landsat spectral bands. a – visible spectrum, 0.45 – 0.69 µm (bands 1 3); b – infrared spectrum, 0.76 – 0.90 µm (band 4); c – thermal radiation, 10.4 12.5 µm. table 1. landsat spectral bands. spectral bands wavelength (µm) resolution (ms) use band 1 (blue) 0.45–0.52 30 bathymetric mapping; distinguishes soil from vegetation; deciduous from coniferous vegetation. band 2 (green) 0.52–0.61 30 emphasizes peak vegetation, which is useful for assessing plant vigour. band 3 (red) 0.63–0.69 30 emphasizes vegetation slopes. band 4 (ir) 0.76–0.90 30 emphasizes biomass content and shorelines. band 5 (ir) 1.55–1.75 30 discriminates moisture content of soil and vegetation; penetrates thin clouds. band 6 (thermal) 10.4–12.5 120/60 useful for thermal mapping and estimated soil moisture. band 7 (ir) 2.08–2.35 30 useful for mapping hydrothermally altered rocks associated with mineral deposits. g eologia c roatica alijagić and šajn: application and improvement of soil spatial distribution mapping using advanced modeling techniques 77 29 rows). extracting information from satellite imagery often involves image interpretation techniques as well as gis integration of other spatial data. multispectral satellite imagery offers several advantages, such as a large number of data records, the availability of repeated images of a single place at different times, and the fact that virtually the entire planet is covered. we used images from 1990, in a period of intensive mining and smelting, and from 2005 after the civil war, a period when production was stopped. 3.4. data transformation transforming data means performing the same mathematical operation on each piece of original data the main purpose of which is to reduce the difference between extreme values (gringarten & deutsch, 2001). it is often observed that environmental variables are log-normal (krige, 1951, 1960; rose at al., 1979) or positively skewed (zhang et al., 1995; zhang & selinus, 1998), and data transformation is necessary to normalise such data sets. the box-cox transformation represents one of the most frequently used transformations in environmental sciences and geosciences where power transformation is needed (box & cox, 1962; jobson, 1991; zhang et al., 1998; mcgrath, et al., 2004). the box-cox transformation is given by: y x = − ≠ l l l 1 0; where y is the transformed value, and x is the value to be transformed. 3.5. modeling techniques 3.5.1. kriging kriging is one of the most popular geostatistical prediction methods successfully applied widely in the estimation and mapping of soil attributes in unsampled areas giving the best linear unbiased prediction of the concentration with minimal variance (li et al., 2016). kriging has become a quite effective tool for the study of hazard risk assessments and spatial uncertainty in general (goovaerts, 1999, 2001), but at the same time it enables quantification of the main spatial characteristic of soil attributes and spatial interpolation methods considering only the neighbouring points of estimation data (carlon et al., 2001; theodossiou & latinopoulos, 2006). the most commonly used geostatistical prediction method is ordinary kriging that uses a semivariance function based on the assumption that nearby objects tend to be more similar than those that are farther apart. an unbiased estimator of the semivariance function is half of the average squared difference between paired data values (oliver & webster, 2014): y h n h z x z x h i n h ( ) ( ) ( ) ( ) ( ) = − +[ ] = ∑1 2 1 1 2 1 where γ(h) is the semivariance at a given distance h; and n(h) is the number of sample pairs in h, and z(xi + h) and z(xi) are sample values at two points separated by h. the variogram model mathematically specifies the spatial variability of the data set and the resulting grid file. the interpolation weights, which are applied to data points during the grid node calculations, are direct functions of the variogram model (webster & oliver, 2001). the graphical display is the final goal of many environmental scientists in the chain of steps that begins with sampling the prime objective of which is to utilise the power of the visual appearance (oliver & webster, 2014). 3.5.2. artificial neural network – multilayer perceptron an artificial neural network (ann) is an information-processing paradigm that is inspired by biological nervous systems, which is both relatively easy to implement and very reliable (aitkenhead et al., 2012). it is composed of a large number of highly interconnected processing elements (neurons or nodes) working in unison to solve specific problems. an ann is configured for a specific application, such as pattern recognition or data classification, through a learning process. learning in biological systems involves adjustments to the synaptic connections that exist between the neurons (žibret et al., 2012). the development of layered feed-forward anns began in the late 1950s by rosenblatt‘s perceptron as the first model for learning with a teacher (i.e. supervised learning), which is often referred to as a single-layer perceptron. the multilayer perceptron (mlp) is one of the most popular feedforward anns that performs tasks such as function fitting and pattern recognition problems (asce, 2000). mlp can be used for the classification of linearly inseparable patterns and can also work as universal approximators. mlps are feedforward neural networks (fnns) with one or more layers of units between the input and output layers (du & swamy, 2006; agirre-basurko et al., 2006; danandeh & nourani, 2017). the output of a neuron is given by: x = − = − = ∑w x b w x bi i t i n 1 y = s x( ) whereis the ith input, wi is the link weight from the ith input, w = (wi ... wn)t, x = (x1 ... xn)t, b is a threshold or bias, and is the number of inputs. the activation function is usually some continuous or discontinuous function mapping the real numbers into the interval (-1,1) or (0,1) (du & swamy, 2006). a different function can be used as an activation function but the most used is the sigmoidal activation function. a standard sigmoidal activation function has the following form: s x x( ) � = + 1 1 e the success of the method can be laid down for the following reasons: (1) they can model extremely complex systems and due to their nature can be used to model nonlinear natural systems (linearity in the sense of mathematical properties of additivity and homogeneity); when using linear algebra (such as most of the multivariate statistics) to describe nonlinear systems we always have to make approximations; (2) there is no limitation with the dimensionality of the problem; it can be arbitrary, depending on the cpu speed and memory, and (3) simple and successful operation due to well-developed learning algorithms (žibret et al., 2012). 3.5.3. multiple polynomial regressions multiple regression, the term first used by pearson (pearson, 1908 in kelechi, 2012). refers to a regression application the main purpose of which is to learn more about the relationship between several independent or predictor variables and a dependent or criterion variable. polynomial regression is a special case of multiple regression in which the relationship between the ing eo lo gi a c ro at ic a geologia croatica 73/178 dependent variable and the dependent variable is modelled as an mth order polynomial (ostertagová, 2012). the general polynomial regression model is given by: y x x x xi m m i= + + + + + +b b b b b e0 1 2 2 3 3 ... where, for a set of i observations, yi is the predictand variable, β0 is a regression constant, β1,β2,…,βm are the coefficients of the x, x2,…, -xm independent variables (predictors), m is the order of the polynomial, and ɛi is the model error (the difference between observations and predicted values). although polynomial regression fits a nonlinear model to the data, the estimation problem is linear because the regression coefficients are linear in the parameters (kerrou et al., 2017). the goal of the regression analysis is to determine the values of the parameters of the regression equation and then to quantify the goodness of the fit in respect of the dependent variable (agirrebasurko et al., 2006). two following values: r2 and adjusted r2 describe how well the model fits the data. all regression models provide information regarding the influence of the combined interactions of the estimator variables on the response. however, the major conceptual limitation of the regression techniques is that one can only ascertain relationships, but never be sure about the underlying causal mechanism. 4. results and discussion 4.1. linear mathematical methods vs. artificial neural networks (ann-mp) the collection of geospatial data has already begun with data acquisition. from the land use map and digital elevation model (dem), many geospatial data had been sourced and later used in modeling. the main purpose of using such parameters (data) is the construction of a spatial distribution map of particular elements as a final product. geochemical maps, as final products are necessary for understanding both natural and anthropogenic distributions. due to the high cost and time-consuming nature of soil sampling, research in developing methods for the creation of soil maps from sparse soil data is becoming increasingly important. in recent years, the development of prediction methods (linear and nonlinear) that use secondary attributes sourced from the dem, land use, and remote sensing in combination with sparse and expensive soil measurements has been sharpening the focus of this research. consequently, the potential for applying such information to soil mapping is greater than ever before. applying various modeling techniques, different prediction methods for soil types were compared, but we also choose the best combination of prediction method and secondary information. various modeling techniques help us reconstruct different processes that influenced the entire study area simultaneously. their main purpose is not only the isolation of hotspots with the highest concentrations but also a spatial distribution pattern of particular trace elements. simultaneously they distinguish natural and anthropogenic influences as well as the transportation pattern, such as atmospheric or water transport of trace elements. studying this pattern will help in better interpretation and understanding of the processes that occurred in whatever particular period of time, they are related to. all the aforementioned data were used for preparing two spatial distribution models using two prediction methods, modeling by multiple polynomial regression (mpr) and artificial neural network multilayer perceptron (ann-mp), respectively. for both modeling methods, a recall grid has been used. the whole study area was divided into 50 x 50 m grids. the total number of recall points is 41,471. besides the standard position parameters, each particular recall point is also described by some new geospatial parameters. both methods were treated using the same conditions and same software packages, statistica 11 (stat soft inc., 2012) and surfer 11 (golden software inc., 2012). the kriging is a linear method and only considers the sparse measured data. modeling by ann-mp was undertaken using a large amount of input data; 240 of the hidden units and 25 train networks. aiming for the best model, we tried changing some input data; the number of neurons, as well as the number of training networks. our experience showed that more neurons and more neural architectures produced better results. models were constructed first for each particular element, then for groups of elements extracted by factor analysis. each particular model is trained to 25 networks but only 5 logical networks were retained, and finally, an average model of 5 retained networks was calculated. each training model contains a summary table with the following parameters: training perfection, test perfection, validation perfection, all perfection, training error, test error, validation error, training algorithm, hidden activation, and output activation. many data conversions, corrections and transformations had to be done prior to obtaining useful models. the main reason that we used so many different input data in modeling by mpr, lies in the fact that this method is very demanding compared to the ann-mp. the developed methods and procedures, especially annmp, mpr as a control method and kriging as a modified, worldwide successfully established method, have been used to predict the concentration of four leading elements pb, ni, ti, and as from their previously identified geochemical association. lead is a typi cal anthropogenic element, introduced solely by mining and smelting activities. nickel and titanium are typical natural elements, whose enrichment depends mainly on the parental material degradation, and the vague distributiom of arsenic can be probably explained with its enrichment in independent outcropping rocks (aijagić et al., 2015). further processing of the factor score values is avoided because they represent the new synthetic variables which are calculated and presented as the standard values. this means that those methods can only determine relative enrichment relationships. in any case, with any certainty, we cannot judge the prediction of the absolute values. the essence of the whole approach is that under the same conditions all three tested methods should give some stable distribution of results of the areas with anthropogenically enriched elements as well as examining natural enrichment. the expected results must be stable in all cases. procedures, approaches, preparing data and calculations were being developed over time until they become stable. the stable procedures are procedures under the same conditions that correctly predict the distribution of elements that represent the geochemical characteristics of the landscape. the estimation of reliability of the predictions and model applicability lies in the fact that all the given models are repeatable. so the developed procedures are not random or specific to a particular item or an isolated area, but such models can be applied anywhere, even in the distribution of some other observations. we critically evaluated the methods according to the significance of the applied transformations, the similarity between models, as well as the stability of predictions. basically, this represents the biggest contribution of this paper. g eologia c roatica alijagić and šajn: application and improvement of soil spatial distribution mapping using advanced modeling techniques 79 since computer equipment allows us to prepare a very large number of solutions in real-time, we used the principle which was used for knotting the enigma coding system (the german coding system in the second world war). the principle is very simple. discard illogical solutions and focus on those that are logical. the basic principle (principle of ockham cat) was applied: everything that happens around us must be logical and indeed simple. 4.2. contamination and natural enrichment of chemical elements (application of models) 4.2.1. anthropogenic impact the spatial distributions of three common anthropogenic chemical elements cd, pb, and zn according to the newdutch list (esdat, 2013) are presented in fig. 9. for a graphical display of spatial distribution, the maps with target and intervention values have been used, where different colours represent different concentration arrangements. in the scale used for its distribution we used five ranges: two green colours represent the ranges under the target values; the light green is one half of the target values; the yellow range represents the target values, the orange is one half of the sum of both, target and intervention, and the red range represents the intervention values. according to the newdutch list (esdat, 2013), the target value for cd is 0.8 mg/kg, for pb 85 mg/kg, and for zn 140 mg/kg. the intervention value for cd is 12 mg/kg, for pb 530 mg/kg, and for zn 720 mg/kg. high concentrations of these three chemical elements exceed their intervention values only in zone 1 and in alluvial soils. several samples with their high concentrations are collected from these two units with maximum concentrations in the range of 4.0 – 7.2 mg/kg cd, 880 – 1,700 mg/kg pb and 1,500 – 3,100 mg/kg zn. the maximum concentration of cd is 7.2 mg/kg, pb 1,700 mg/kg, and zn 3,100 mg/kg. if we compare these values to their target values, they exceed 9 times the maximum for cd, 20 times for pb, and 22 times for zn, respectively. even the intervention values are exceeded by more than 3 times for pb, and 4 times for zn. almost the entire area is not contaminated with the aforementioned figure 9. spatial distribution of cd–pb–zn pollution according to the newdutch list (esdat, 2013) recommendation: a – kriging; b – multiple polynomial regression (mpr); c – artificial neural network – multilayer perceptron (ann-mp). g eo lo gi a c ro at ic a geologia croatica 73/180 group, except for the two isolated units, alluvial soils and the industrial zone 1? fine-grained clay-sized particles are transported far from the source of contamination and have been detected by the three applied methods. the concentrations under the target values are detected at 73 km2 or 70 % of the entire study area with kriging, 70 km2 or 68 % with mpr and 77 km2 or 74.5 % with ann-mp. the first model extracts about 28 km2 or 27 % between the target values and intervention values (yellow and orange colour), the second model about 31km2 or 30 %, and the third model about 24 km2 or 23 %. the range that represents concentrations higher than the intervention values are isolated on about 2.5 km2 or 2.5 % of the study area with kriging and ann-mp and 2 km2 or 2 % with mpr (table 2). 4.2.2. natural enrichment the spatial distribution of natural enrichment is presented in the summarized map of co, ni, and cr (fig. 10). these prediction models show an arrangement in natural enrichment across the study area. for a graphical display of the spatial distribution, the maps with target and intervention values are presented, where different colours represent changes within them. the used colour scale is the same as for the anthropogenic impact (fig. 9). according to the newdutch list (esdat, 2013), the target value for ni is 35 mg/kg, co 20 mg/kg, and cr 100 mg/kg, but the intervention value for ni is 210 mg/kg, co 240 mg/kg, and cr 380 mg/kg. the maximum concentration of ni is 500 mg/kg, co 64 mg/kg, and cr 460 mg/kg. comparing these values to the target values of the newdutch list (esdat, 2013), natural enrichment exceeded 14 times for ni, 3 times for co, and 46 times for cr. compared to the intervention values, they exceed the values by 2.5 times for ni and for cr are more than the same again? it seems that the major enrichment is from ni and cr. all three models identify one major hotspot with its intervention concentration, the jurassic and cretaceous flysch, but also some outcropping rocks on the oligocene clastite complex. the first model isolates about 9 km2 or 9 % of the total study area figure 10. the spatial distribution of natural enrichment co–cr–ni according to the newdutch list (esdat, 2013) recommendation: a – kriging; b – multiple polynomial regression (mpr); c – artificial neural network – multilayer perceptron (ann-mp). g eologia c roatica alijagić and šajn: application and improvement of soil spatial distribution mapping using advanced modeling techniques 81 (103.7 km2), under the range of target values (two green colours), the second model identifies about 11.2 km2 or 11 %, and the last model about 8.6 km2 or 8 %. almost all the study area is enriched with these elements (yellow and orange colours), where all three applied models isolated the majority of the territory: kriging and ann-mp about 85 km2 or 82 % and mpr 82 km2 or 79 % (table 2). intervention values are observed at 10 km2 or 10 % of the entire study area with all applied models. the spatial distribution of arsenic according to the newdutch list (esdat, 2013) within all prediction methods is provided in fig. 11. the target value for as is 29 mg/kg and the intervention value is 55 mg/kg. comparing the values for as with the newdutch list (esdat, 2013), its concentrations exceed the target values at 35 km2 with kriging, 38 km2 with mpr and 41 km2 with ann-mp (table 2). for area between 18-26 km2 its concentrations exceed the intervention value for as. comparing the surfaces of all the selected elements (pb, zn, cr, ni) that includes major anthropogenic impact and natural enrichment, the natural enrichment with arsenic is the greatest. this enrichment has been absolutely unexpected and needs special attention in future investigations. total contamination (as-cd-co-cr-ni-pb-zn) that includes anthropogenic impact and geogenic enrichment, respectively exceeds their target values over two-thirds of the entire study area, and one-third of their values exceed the intervention values. the total contamination is not a simple summary of these two types of contamination but it is necessary to mention that some spatial distributions are overlapping, and those final values seem lower than the summary of their particular distributions. 5. conclusion along the stavnja river valley, intensive mining and smelting activities have been occurring for more than 100 years. diverse mineral occurrences, especially iron deposits and lead-zinc deposits make this study area interesting for geochemical research. also, this study area was a place of intensive military operation figure 11. the spatial distribution of arsenic according to the newdutch list (esdat, 2013) recommendation: a – kriging; b – multiple polynomial regression (mpr); c – artificial neural network – multilayer perceptron (ann-mp). g eo lo gi a c ro at ic a geologia croatica 73/182 during the last war, 1992–1995, which resulted in numerous remaining minefields, thus making this research more complex. the spatial distributions of particular trace elements are aiding the reconstruction of their main pathway in the study area and simultaneously isolating their hotspots. the problem of contamination along the river represents an anisotropic appearance between the isotropic lithological units and cannot be solved completely by standard interpolation kriging methods, based only on sparse soil measurements. two new powerful linear and nonlinear modeling techniques are applied for solving this problem. their arrangement in concentration across the stavnja river valley is more realistic and picturesque because they include more geospatial and geomorphological data such as geological background, land use, aspect, slope, altitude, etc. including all the aforementioned facts, results in better interpretation and understanding of the processes that occurred during the particular period of time that they are related to. various modeling techniques help to reconstruct different processes that affected the entire area. their main purpose is not only the isolation of hotspots with the highest concentrations. they simultaneously distinguish natural from anthropogenic influences as well as the transportation pattern (such as atmospheric or water transport). summarised maps that comprise solely three anthropogenic trace elements (pb-zn-cd) and three natural trace elements (nico-cr) according to the newdutch list (esdat, 2013) provide information about the overall anthropogenic impact and natural enrichment of study area. the results show: 1. all provided models indicate that natural enrichment is much higher than the anthropogenic impact. about 71 % or 73 km2 is under target values, in the range between target and intervention values about 26.5 % or 26 km2, and over the intervention values by only about 2-2.5 % or 2-2.5 km2 of entire study area for pb-zncd. 2. natural enrichment (ni-co-cr) shows the opposite situation, whereby only about 9 % or 10 km2 is under target values, about 84 km2 or 80 % between intervention and target values, and 10 % or 10 km2 over intervention values of the study area. 3. the three applied models are repeatable, which means that very similar spatial distribution can be obtained under the same conditions, with an unrestricted number of applications. the very important characteristic of each particular model is that one model isolates all the hotspots simultaneously. on the other hand, their similarities are confirmation and validation of all the different models at the same time. an important success in such modeling is that all models are repeatable. 4. natural enrichment with arsenic is the highest result. this enrichment has been absolutely unexpected and needs special attention in future investigations. references asce (2000): committee on the application of anns in hydrology artifical neural networks in hydrology i: preliminary concepts.– journal of hydrological engineering, 5/2, 115–123. agirre-basurko, e., ibarra-berastegi, g. & madariaga, i. (2006): regression and multilayer perceptron-based models to forecast hourly o3 and no2 levels in the bilbao area.– environmental modeling & software, 21, 430–446. doi: 10.1016/j.envsoft.2004.07.008 aitkenhead, m.j., coull, m.c., towers, w., hudson, g. & black, h.i.j. (2012): predicting soil chemical composition and other soil parameters from field observations using a neural network.– computers and electronics in agriculture, 82, 108–116. doi:10.1016/j.compag.2011.12.013 alijagić, j. & šajn, r. (2010): distribution of chemical elements in an old metallurgical area, zenica (bosnia and herzegovina).– geoderma, 162/1–2, 71–85. doi: 10.1016/j.geoderma.2011.01.007 alijagić, j. & šajn, r. (2006): influence of ironworks on distribution of chemical elements in bosnia and herzegovina and slovenia.– geologija, 49/1, 123–132. doi:10.5474/geologija.2006.010 alijagić, j., šajn, r. & rokavec, d. (2015): impact assessment of mining and metallurgical activities on the distribution of trace elements in the stavnja valley, bosnia and herzegovina.– in: daniels, j.a. (ed.): advances in environmental research – nova science publisher, 42, 139–200. alijagić, j. (2013): application of multivariate statistical methods and artificial neural network for separation natural background and influence of mining and metallurgy activities on distribution of chemical elements in the stavnja valley (bosnia and herzegovina).– phd dissertation, university of nova gorica, 110 p. alijagić, j. (2008): distribution of chemical elements in an old metallurgic area, zenica (central bosnia).– master dissertation, masaryk university of brno, 100 p. al-khashman, o.a. & shawabkeh, r.a. (2009): metal distribution in urban soil around steel industry beside queen alia airport, jordan.– environmental geochemistry and health, 31/6, 717–726. doi:10.1007/s10653-009-9250-9 autodesk, inc. (2012): autodesk map 3d, version 2012 – software. autodesk, inc. (http://www. autodesk.com) bagheri bodaghabadi, m., martínez-casasnovas, j., salehi, m.h., mohammadi, j., esfandiarpoor borujeni, i., toomanian, n. & gandomkar, a. (2015): digital soil mapping using artificial neural networks and terrain-related attributes.– pedosphere, 25/4, 580–591. doi: 10.1016/s1002-0160(15)30038-2 box, g.e.p. & cox, d.r. (1962) an analysis of transformations.– journal of the royal statistical society, series b, 26/2, 211–252. doi: 10.1111/j.2517-6161.1964. tb00553.x bradl, h.b. (2005): sources and origins of heavy metals.– heavy metals in the environment, 1–27. doi: 10.1016/s1573-4285(05)80020-1 burrough, p.a. (1986): principles of geographic information systems for land resources assessment.– oxford: oxford university press, 193 p. carlon, c., critto, a., marcomini, a. & nathanail, p. (2001): risk based characterisation of contaminated industrial site using multivariate and geostatistical tools.– environmental pollution, 111/3, 417–427. doi: 10.1016/s02697491(00)00089-0. chopin, e.i.b. & alloway, b.j. (2007): distribution and mobility of trace elements in soils and vegetation around the mining and smelting areas of tharsis, ríotinto and huelva, iberian pyrite belt, sw spain. water, air, and soil pollution, 182/1–4, 245–261. doi: 10.1016/j.scitotenv.2006.11.037 danandeh, m.a. & nourani, v. (2017): a pareto-optimal moving average-multigene genetic programming model for rainfall-runoff modeling.– environmental modeling & software, 92, 239–251. doi: 10.1016/j.envsoft.2017.03.004 du, k.l. & swamy, m.n.s. (2006): neural networks in an softcomputing framework. springer – verlag, london, 566 p. dudka, s. & adriano, d.c. (1997): environmental impacts of metal ore mining and processing: a review.– journal of environmental quality, 26, 590–602. doi: 10.2134/jeq1997.00472425002600030003x esdat (2013): dutch target and intervention values, 2000 (the newdutch list). ministry of infrastructure and the environment. url: http://www.esdat.com.au/. esri, inc. (2004): arcinfo ver 9, software.– environmental research institute (http:// www.esri.com/) table 2. areas of natural enrichment and pollution according to the newdutch list (esdat, 2013) recommendation. anthropogenic origin (cd-pb-zn) target level (km2) intervention level (km2) kriging 28 2.5 mpr 31 2.2 ann-mp 24 2.6 natural origin (co-cr-ni) kriging 85 9.7 mpr 82 10 ann-mp 85 10 natural origin (as) kriging 35 26 mpr 38 20 ann-mp 41 18 total (as-cd-co-cr-ni-pb-zn) kriging 64 37 mpr 67 30 ann-mp 68 30 g eologia c roatica alijagić and šajn: application and improvement of soil spatial distribution mapping using advanced modeling techniques 83 ferreira, v., koricheva, j., duarte, s., niyogi, d.k. & guérold, f. (2016): effects of anthropogenic heavy metal contamination on litter decomposition in streams – a meta-analysis.– environmental pollution, 210, 261–270. doi: 10.1016/j.envpol.2015.12.060 fisher, p.f. & tate, n.j. (2006): causes and consequences of error in digital elevation models.– progress in physical geography, 30/4, 467–489. doi:10.1191/ 0309133306pp492ra golden software, inc. (2012): surfer (surface mapping system), ver 11 – software.– golden software, inc. (http://www.goldensoftware.com/) google inc. (2010). google earth. area breza vareš (http://earth.google.com) goovaerts, p. (2001): geostatistical modeling of uncertainty in soil science.– geoderma, 103/1–2, 3–26. doi:10.1016/s0016-7061(01)00067-2 goovaerts, p. (1999): geostatistics in soil science: state of the art and perspectives.– geoderma, 89/1, 1–45. doi:10.1016/s0016-7061(98)00078-0 gringarten, e. & deutsch, c.v. (2001): teacher’s aide: variogram interpretation and modeling.– mathematical geology, 33/4, 507–534. doi:10.1023/a:1011093014141 guth, p.l. (2006): geomorphometry from srtm – comparison to ned. photogrammetric engineering and remote sensing, 72/3, 269–277. doi:10.14358/pers. 72.3.269 hill, l.l. (2006): georeferencing: the geographic associations of information, 2. cambridge, ma: mit press, 280 p. doi: 10.7551/mitpress/3260.001.0001 honghai, q. & altinakar, m.s. (2011): a gis-based decision support system for integrated flood management under uncertainty with two dimensional numerical simulations.– environmental modeling and software, 26/6, 817–821. doi: 10.1016/j.envsoft.2010.11.006 jain, s.k. & singh, v.p. (2003): water resources systems planning and management, 51, 858 p. jobson, j.d. (1991): applied multivariate data analysis.– regression and experimental design, springer-verlag, new york, 1, 662 p. doi: 10.1007/978-1-4612-0921-8 kabata-pendias, a. & pendias, h. (2001): trace elements in soils and plants. third edition.– crc press llc, boca raton, florica, 403 p. doi: 10.1201/b10158 kelechi, a.c. (2012): regression and principal component analyses: a comparison using few regressors.– american journal of mathematics and statistics, 2/1, 1–5. doi: 10.5923/j.ajms. 20120201.01 kerrou, j., deman, g., tacher, l., benabderrahmane, h. & perrochet, p. (2017): numerical and polynomial modeling to assess environmental and hydraulic impacts of the future geological radwaste repository in meuse site (france).–environmental modeling & software, 97, 157–170. doi: 10.1016/j.envsoft.2017.07.018 krige, d.g. (1960): on the departure of ore value distributions from lognormal models in south african gold mines.– journal of the south african institute of mining and metallurgy, 61, 231–244. krige, d.g. (1951): a statistical approach to some basic mine valuation problems on the witwatersrand.– journal of the chemical, metallurgical and mining society of south africa, 52/6, 119–139. lagacherie, p. & mcbratney, a.b. (2007): chapter 1. spatial soil information systems and spatial soil inference systems: perspectives for digital soil mapping.– in: lagacherie, p., mcbratney, a.b. & voltz, m. (eds.): digital soil mapping, an introductory perspective. developments in soil science, amsterdam, 31, 3–24. doi: 10.1016/s0166-2481(06)31001-x li, y., zhu, a.-x., shi, z., liu, j. & du, f. (2016): supplemental sampling for digital soil mapping based on prediction uncertainty from both the feature domain and the spatial domain.– geoderma, 284, 73–84. doi: 10.1016/j.geoderma.2016.08.013 mcbratney, a.b., mendonça santos, m. & minasny, b. (2003): on digital soil mapping.– geoderma, 117, 3–52. doi: 10.1016/s0016-7061(03)00223-4. mcgrath, d., zhang, c. & carton, o.t. (2004): geostatistical analyses and hazard assessment on soil lead in silvermines area, ireland.– environmental pollution, 127/2, 239–248. doi: 10.1016/j.envpol.2003.07.002 mitasova, h. & hofierka, j. (1993): interpolation by regularized spline with tension: ii. application to terrain modeling and surface geometry analysis.– mathematical geology, 25/6, 657–669. doi:10.1007/bf00893172 moor, i.d., lewis, a. & gallant, j.c. (1993): terrain properties: estimation methods and scale effects.– in: jakeman, a.j. (ed.): modeling change in environmental systems, john wiley and sons, new york, 189–214. mukherjee, s., joshi, p.k., mukherjee, s., ghosh, a., garg, r.d. & mukhopadhyay, a. (2013): evaluation of vertical accuracy of open source digital elevation model (dem).– international journal of applied earth observation and geoinformation, 21, 205–217. doi: 10.1016/j.jag.2012.09.004 navarro, m.c., pérez-sirvent, c., marti̇nez-sánchez, m.j., vidal, j., tovar, p.j. & bech, j. (2008): abandoned mine sites as a source of contamination by heavy metals: a case study in a semi-arid zone.– journal of geochemical exploration, 96/4, 183–193. doi: 10.1016/j.gexplo.2007.04.011 oliver, m.a. & webster, r. (2014): a tutorial guide to geostatistics: computing and modeling variograms and kriging.– catena, 113, 56–69. doi: 10.1016/j.catena.2013.09.006 ostertagová, e. (2012): modeling using polynomial regression.– procedia engineering, 48, 500–506. doi: 10.1016/j.proeng.2012.09.545 palinkaš, l.a., šoštarić, s.b. & palinkaš, s.s. (2008): metallogeny of the northwestern and central dinarides and southern tisia.– ore geology reviews, 34, 501–520. doi:10.1016/j.oregeorev.2008.05.006 pavlowsky, r.t., lecce, s.a., owen, m.r. & martin, d.j. (2017): legacy sediment, lead, and zinc storage in channel and floodplain deposits of the big river, old lead belt mining district, missouri, usa.– geomorphology, 299, 54–75. doi: 10.1016/j.geomorph.2017.08.042 pearson, h.w. (1908): the place of the great raised beaches in geology.– science, new ser., 27, 189–190. ramlal, b. & baban, s. (2008): developing a gis based integrated approach to flood management in trinidad, west indies.– journal of environmental management, 88/4, 1131–1140. doi:10.1016/j.jenvman.2007.06.010 romić, m. (2012): bioavailability of trace metals in terrestrial environment: methodological issues.– european chemical bulletin, 1/11, 489–493. doi: 10.17628/ ecb.2012.1.489-493 rose, a.w., hawkes, h.e. & webb, j.s. (1979): geochemistry in mineral exploration, 2nd edition.– academic press, london, 657 p. scull, p., franklin, j., chadwick, o.a. & mcarthur, d. (2003): predictive soil mapping: a review.– progress in physical geography, 27, 171–197. doi: 10.1191/0309133303pp366ra shallari, s., schwartz, c., hasko, a. & morel, j.l. (1998): heavy metals in soils and plants of serpentine and industrial sites of albania.– science of the total environment, 209, 133–142. doi: 10.1016/s0048-9697(98)80104-6 singh, k.p., basant, n., malik, a. & jain, g. (2010): modeling the performance of “up-flow anaerobic sludge blanket” reactor based wastewater treatment plant using linear and nonlinear approaches – a case study.– analytica chimica acta, 658/1, 1–11. doi: 10.1016/j.aca.2009.11.001 spark, r.n. & williams, p.f. (1996): digital terrain models and the visualization of structural geology.– computer methods in the geosciences, 15, 421–446. doi: 10.1016/s1874-561x(96)80032-0 stafilov, t., šajn, r., boev, b., cvetković, j. & mukaetov, d. (2008a): geochemical atlas of kavadarci and the environment – sts. cyril and methodius university, faculty of natural science, skopje, 109 p. stafilov, t., šajn, r., pančevski, z., boev, b., frontasyeva, m.v. & strelkova, l. (2008b): geochemical atlas of veles and the environs.– sts. cyril and methodius university, faculty of natural sciences and matematics, skopje, 123 p. statistica stat soft, inc. (2012) (data analysis software system): version 11 – software. stat soft, inc. (www.statsoft.com) šajn r., halamić, j., peh, z., galović, l. & alijagić, j. (2011): assessment of the natural and anthropogenic sources of chemical elements in alluvial soils from the drava river using multivariate statistical methods.– journal of geochemical exploration, 110/ 3, 278–289. doi:10.1016/j.gexplo.2011.06.009 šajn, r. (2006): factor analysis of soil and attic-dust to separate mining and metallurgy influence, meža valley, slovenia.– mathematical geology, 38/6, 735–747. doi: 10.1007/s11004-006-9039-7 šajn, r. (2005): using attic dust and soil for the separation of anthropogenic and geogenic elemental distributions in an old metallurgic area (celje, slovenia).– geochemistry, exploration environment analysis, 5/1, 59–67. doi: 10.1144/14677873/03-050 the cgiar consortium for spatial information (2011): srtm 90m digital elevation data. database: srtm_40_04 (http://srtm.csi.cgiar.org) theodossiou, n. & latinopoulos, p. (2006): evaluation and optimisation of groundwater observation networks using the kriging methodology.– environmental modeling & software, 21/7, 991–1000. doi: 10.1016/j.envsoft.2005.05.001 thompson, j.a., bell, j.c. & butler, c.a. (2001): digital elevation model resolution: effects on terrain attribute calculation and quantitative soil-landscape mode ling.– geoderma, 100, 67–89. doi:10.1016/s0016-7061(00)00081-1 thornton, p.e., running, s.w. & white, m.a. (1997): generating surface of daily meteorological variable over large regions of complex terrain.– journal of hydrology, 190/3, 214–250. doi:10.1016/s0022-1694(96)03128-9 u.s. geological survey (2011a): aster global digital elevation data (30 m). database: 20130113055119_468788446 (http://gdex.cr.usgs.gov/gdex/) u.s. geological survey (2011b): global land survey multispectral landsat satelite images p187-r29. databases: p188r029_5x19920914 and le71880292007259asn00 (http://earthexplorer. usgs.gov/) u.s. geological survey (2011c): landsat project description and land remote sensing (http://landsat.usgs.gov/) vassilopouloua, s., hurni, l., dietrich, v., baltsavias, e., pateraki, m., lagios, e. & parcharidis, i. (2002): orthophoto generation using ikonos imagery and high-resolution dem: a case study on volcanic hazard monitoring of nisyros island (greece).– isprs journal of photogrammetry and remote sensing, 57, 24–38. doi:10.1016/s0924-2716(02)00126-0 webster, r. & oliver, m.a. (2001): geostatistics for environmental scientists.– john wiley and sons ltd, chichester, 271 p. doi: 10.1002/9780470517277 wechsler, s.p. (2003): perceptions of digital elevation model uncertainty by dem users.– urisa journal, 15/2, 57–64. g eo lo gi a c ro at ic a geologia croatica 73/184 wise, s.m. (1998): the effect of gis interpolation errors on the use of digital elevation models in geomorphology.– in: lane, s.n., richards, k.s. & chandler, j.h. (eds.): landform modeling, monitoring and analysis. john wiley and sons ltd, chichester, 466 p. wolock, d.m. & price, c.v. (1994): effects of digital elevation model map scale and data resolution on a topography-based watershed model.– water resources research, 30/11, 3041–3052. doi:10.1029/94wr01971 yaalon, d.h. (1989): the earliest soil maps and their logic. bulletin of the international society of soil science.– international society of soil science, wageningen p 24. yi, q., dou, x.d., huang, q.r. & zhao, x.q. (2012): pollution characteristics of pb, zn, as, cd in the bijiang river.– procedia environmental sciences, 13, 43–52. doi: 10.1016/j.proenv.2012.01.004 zhang, c.s. & selinus, o. (1998): statistics and gis in environmental geochemistrysome problems and solutions.– journal of geochemical exploration, 64/1–3, 339–354. doi: 10.1016/s0375-6742(98)00048-x zhang, c.s., selinus, o. & schedin, j. (1998): statistical analyses on heavy metal contents in till and root samples in an area of southeastern sweden.– the science of the total environment, 212/2–3, 217–232. doi: 10.1016/s00489697(97)00341-0 zhang, c.s., zhang, s., zhang, l.c. & wang, l.j. (1995): background contents of heavy metals in sediments of the changjiang river system and their calculation methods.– journal of environmental sciences, 7/4, 422–429. zhang, w. & montgomery, d.r. (1994): digital elevation model grid size, landscape representation, and hydrologic simulations.– water resources research, 30/4, 1019–1028. doi: 10.1029/93wr03553 zhang, l., lyman, s., mao, h., lin, c.j., gay, d.a., wang, s. & wania, f. (2017): a synthesis of research needs for improving the understanding of atmospheric mercury cycling – atmospheric chemistry and physics discussions, 1–29. doi: 10.5194/acp-2017-375 zhao, x., dai, j. & wang, j. (2013): gis-based evaluation and spatial distribution characteristics of land degradation in bijiang watershed.– springerplus, 2, s8. doi: 10.1186/2193-1801-2-s1-s8 žibret, g., šajn, r., alijagić, j. & stafilov, t. (2012): use of neural networks in the geochemical data interpretation.– zeitschrift für geologische wissenschaften, 40/4–5, 253–266. 2023 | 76/2 | 73–85 | 10 figs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction soil pedocomplexes are unique, highly sensitive natural multicomponent systems capable of forming valuable archives for numerous signals that are indicative of intense palaeoclimatic and palaeoenvironmental changes over time (bronger et al., 1998; bronger, 2003). soil memory preserves diverse components which vary due to the type of evolutionary processes that have taken place during the time since deposition. therefore, combining studies of these complex physical and geo-chemical components allows detailed reconstruction of geoecological trends that drive the naturally induced soil transformation over different spatio-temporal scales (e.g. vasiljević et al., 2011; 2014). unlike modern soils, palaeosols are fossil relics which have undergone pedogenic processes in the geological past, capturing palaeoclimate components of ancient landscapes (nettleton et al., 2000). the danube watershed encompasses complex geological terrains comprised of diverse geomorphic units, such as the alps, bohemian massif, carpathians, dinarides, and the balkan mountains. the catchment has been a valuable source of thick loess deposits for study, which are especially well preserved within the middle danube basin, with sections dating back until at least the mid-quaternary (e.g. fenn et al., 2022; wacha et initial results of the colorimetric indices of the oldest exposed pedocomplex (titel loess plateau, serbia) tin lukić1, milica g. radaković1*, rastko marković2, warren thompson3, tanja micić ponjiger1, biljana basarin1, nemanja tomić4, vladimir m. tomović5, jovanka popov raljić6, milivoj b. gavrilov1, aleksandar valjarević7, györgy sipos8, dejan filipović7, cezar morar9 and slobodan b. marković1,10 1 university of novi sad, chair of physical geography, department of geography, tourism and hotel management, faculty of sciences, trg dositeja obradovića 3, 21000 novi sad, serbia; (*corresponding author: milicar@dgt.uns.ac.rs) 2 university of niš, chair of regional geography, department of geography, faculty of sciences, višegradska 33, 18000 niš, serbia 3 radiation physics, technical university of denmark, risë campus, fysikvej, 311, kgs. lyngby, denmark 4 university of novi sad, chair of tourism, department of geography, tourism and hotel management, faculty of sciences, trg dositeja obradovića 3, 21000 novi sad, serbia 5 university of novi sad, faculty of technology, bulevar cara lazara 1, 21000 novi sad, serbia 6 singidunum university, faculty of tourism and hotel management, danijelova 32, 11010 belgrade, serbia 7 university of belgrade, faculty of geography, studentski trg 3/iii, 11000 belgrade, serbia 8 university of szeged, geomorphological and geochronological research group, department of geoinformatics, physical and environmental geography, h-6722 szeged, egyetem u. 2-6, hungary 9 university of oradea, department of geography, tourism and territorial planning, 410087 oradea, romania 10 serbian academy of sciences and arts, kneza mihaila 35, 11000 belgrade, serbia doi: 10.4154/gc.2023.05 abstract in this study we present an in-depth description of the colorimetric values for the lowest section of the dukatar loess palaeosol sequence (lps) pedocomplex s5. formed during the marine isotope stage (mis) 13-15, it represents the oldest pedocomplex exposed at the base of the titel loess plateau (tlp), near the confluence of the tisa and danube rivers in vojvodina (northern serbia). the results of low-field magnetic susceptibility measurements (χlf) were compared to colour properties (obtained by conventional methods as well as instrumental measuring) and quantified soil development indices (sdi). of these measurements we found that the redness index (ri1) yielded the most useful results, as this index appears most sensitive to lithological changes and soil development intensity. it was also observed that a high level of correlation existed between χlf, and a* chromaticity. the initial results of this study highlight the utility of colorimetric methods as an interdisciplinary tool when evaluating the presence of ferromagnetics, and the application of rock magnetism to the middle and upper pleistocene lps of the middle danube basin. the presented approach can be used to observe the evolution of climatic and ecological conditions in the given study area, and for establishing correlations between sites extending over the eurasian lps provinces. al., 2021; banak et al., 2016; galović & peh, 2016; sümegi et al., 2019; marković et al., 2013). therefore, danubian river catchment loess deposits preserve some of the longest terrestrial records of palaeoenvironmental and palaeoclimatic changes in central and southeastern europe, and possess great palaeoecological significance (e.g. rubinić et al., 2018; galović, 2014, 2016; banak et al., 2013; marković et al., 2015). in serbia, loess-palaeosol sequences (lps) have been documented predominantly in the northern part of the country (marković et al., 2006; marković et al., 2008, marković et al., 2015; and references therein), but with a few exceptions occurring in southern parts of the carpathian basin (basarin et al., 2014; obreht et al., 2014; boesken et al., 2017; marković et al., 2021b). palaeosols developed on loess can be traced over extensive parts of europe and asia (kukla, 1987), and it is possible to correlate their chronostratigraphy based on different proxies and thus reconstruct pan-continental climate fluctuations. the most common proxies encompass: magnetic properties of soils and loess (radaković et al., 2019), grain size or grain size indices (vandenberghe, 2013), luminescence dating (berger et al., 1992; perić et al., 2019), stable isotopes (schatz et al., 2011), chemical analysis (potter et al., 2021; article history: manuscript received june 13, 2022 revised manuscript accepted may 12, 2023 available online june 16, 2023 keywords: loess, pedocomplex, soil color indices, vojvodina, titel loess plateau, dukatar, north serbia g eo lo gi a c ro at ic a geologia croatica 76/274 fenn et al., 2022), tephrochronology (timar-gabor et al., 2017), palynology (zhang et al., 2017), malacology (ludwig et al., 2021), and colour indices (sprafke et al., 2020). vasiljević et al. (2014) asserts that the aforementioned features of this widely spread sediment and pedocomplexes have proven to be of the utmost scientific, archaeological and agricultural significance within the eurasian loess belt. this study focuses on the colour indices proxy. different colours of lps were recorded by the pioneering loess researcher, aloisius ferdinando marsigli in his “danubius pannonico mysicus” (marsigli, 1726). one and a half centuries later, the geologist aleksandar popovics (1847-1877) wrote about the transition of yellow colour of the loess sediments on the fruška gora mountain in serbia. this study recorded the appearance of a red colour in loess, which is today known as a feature of the regions palaeosols (popovics, 1876). the main topic of our study is the colour of the dukatar lps, which was described primarily by jelena markovićmarjanović (1950), who noted the strong red colour visible at the bottom of the profile. in danubian loess stratigraphy, this layer is referred to as s5; where “s” stands for soil and 5 means that it was formed in the fifth interglacial period, counting from the present (marković et al., 2015). before the above-mentioned proxies were applied to loess research, the colour intensity was used to make connections between multiple loess profiles in serbia and allude to certain aspects of loess plateau geomorphological evolution. counting of the loess (yellow) or palaeosol (red) layers was utilised in around 70 papers in the former yugoslavia in an attempt to correlate loess profiles in serbia. as time passed, the more detailed the descriptions became, and the more differentiated the lps became (marković-marjanović, 1965, and references therein). presently, many lps in serbia still do not have determined colorimetric perspectives. the work of lukić et al. (2014) was the first detailed colour investigation, describing the orlovat lps (fig. 1), in the banat region of serbia. a strong correlation between frequency-dependent magnetic susceptibility and redness index was discovered. the orlovat lps spans the last glacial cycle, with the lowest palaeosol belonging to marine isotope stage (mis) 5, or s1 in danube loess stratigraphy. the second lps in serbia to be characterized in terms of its colorimetric properties was the profile at stalać (obreht et al., 2016). this archive is a valuable record of the transition from the mediterranean to continental climate in the central balkan region, which occurred between mis 9 and mis 1. the most recent profile to be described in terms of its colour proxies is the zemun lps, on the right bank of the danube (laag et al., 2021). the respective authors expanded the search to mis 11, or palaeosol s4. in general, it has been found that the luminance of the lps sediments follows glacial cycles; although in zemun the s4, which is the palest of all palaeosols, the signal is not as distinguishable as in other palaeosols. fortunately, there are other parameters of colour such as redness and blueness, with indices derived from them, that assist our interpretations of the lps, and pedogenetic processes (zykina et al., 2021). interestingly, coloured soils with shades of red and brown are already recognized as touristic attractions, for example in chamarel, mauritius (sheth, et al., 2010). highresolution colour measurements provide detailed palaeoenvironmental markers, which can even be linked to the migration of anatomically modern humans (sprafke et al., 2020). this study aims to characterize the oldest pedocomplex of the titel loess plateau, in terms of its magnetic and colorimetric properties, and the palaeoecological features that outline the scientific and educational values of the given lps. these sites are somewhat endangered by various factors, as presently they remain for the most part unprotected. 2. material and methods 2.1. study area the dukatar site (45°16’59” n, 20°14’33” e) is located 500 m downstream from the settlement of the same name and represents the most complete series of loess-palaeosol sequences of the tlp (fig. 1). it is situated at the foot of a loess section and is available for sampling only during the low water level of the tisa river. the sampled s5 pedocomplex part of the dukatar sequence, is approximately 2.7 m thick and was formed during the early middle pleistocene (e.g. marković et al., 2012). this site belongs to the highest protected zone of the special nature reserve tlp, as indicated with a thick red line in fig. 1 (sgrs, 2012). the site is situated in the contact zone of the tisa river and tlp. after building the dam at novi bečej, north of the tlp, the tisa river has a controlled regime. when the water level is high (aprilmay), it is not possible to reach the dukatar lps, while in september and october it is accessible. the maximum recorded amplitude of the tisa river at the tlp is 876 cm (pavić, 2006). in the north of dukatar there are two famous lps: veliki surduk (big gully) (perić et al., 2019) and feudvar (namier et al., 2021). in the south, three more exist: rogulić surduk, stara ciglana (old brickyard) and kalvarija. the list of protected lps in serbia is quite short: surduk (vujičić et al., 2011), batajnica (višnjić et al., 2016), stari slankamen (vasiljević et al., 2011), and zemun (šarić, 2008). 2.2. sampling strategy a field survey was undertaken prior to the onset of sampling the selected profiles for palaeoclimatic and palaeoecological reconstruction using colorimetric parameters. the field survey, carried out in 2013, involved a detailed description of lps, only then were samples collected for laboratory analysis. efforts were complicated by erosion and rockfall over the surface of the profile, resulting in colluvial deposits of considerable thickness; this greatly affected the consistency of the laboratory results. initial steps included the removal of colluvial deposits and recent vegetation in order to expose the undisturbed surface of the loess section. the next step involved cutting a vertical trench and sampling of the profile. on the tlp, at the site located near the dukatar settlement, a strongly rubified s5 pedocomplex was exposed and sampled. sampling of the s5 pedocomplex on the dukatar profile was undertaken at a high resolution of 3 cm from the bottom part of the l5 unit, across the upper part of the a horizon, on into the ck horizon in the basal part of this strongly rubified palaeosol. a total of 100 bulk samples were taken for palaeopedological research (fig. 2a). in addition, during sampling of this pedocomplex particular care was taken to avoid contact with widespread carbonate concretions in order to obtain valid results of the laboratory analysis. 2.3. magnetic and colorimetric measurements measurement of the χlf of palaeosol samples from the dukatar profile were undertaken at the laboratory of the loess research group at the department of geography, tourism and hotel management, faculty of sciences, university of novi sad, using a portable bartington susceptibility meter set to 300 hz. determing eologia c roatica 75 ing the colour of samples in wet conditions, drying of the samples, and re-examination of the colour in dry conditions was carried out during march and april 2014 at the laboratory for paleoecological reconstruction (laper), department of biology and ecology, faculty of sciences, university of novi sad. following the approach of lukić et al. (2014), the samples were dried in the oven for at least 12 h at 39 °c. instrumental measurement of loess-palaeosol sample colour involved the use of a tristimulus colorimeter, and expressing the obtained values in the cie l a* b* colorimetric system (hünter lab, 2001). this was undertaken at the department of food preservation technology, faculty of technology, university of novi sad. the calculation of rubification (ri) and melanization (mi) indices was performed using the following the approaches provided by harden (1982), harden and taylor (1983), vidić et al. (2004) and vidić and lobnik (1997). this methodology was based on the lotus template by taylor (1988), as it possesses robust approaches for quantification procedures and index calculations. the intensity of rubification indicates the formation of haematite crystals suspended in the soil matrix, which are responsible for the distinctive bright red colour of the soil. the mi indicates accumulation of humus and humic substances in the soil, and the ri quantifies the degree of soil reddening relative to the parent material. mi is used to calculate the degree of darkening (vidić et al., 2004, schaetzl, and anderson, 2005). the redness index (ri1), proposed by harden (1982), can be seen as a proxy for semi-quantitative soil reddening, and is indicative of the proportion of haematite in the pedocomplex. the figure 1. the upper panel shows the wider region of northern serbia and the higher resolution part covers the tisa and danube confluence, with the loess palaeosol sequences over the tlp; the lower panel shows the geological map and protected area of the highest importance indicated with a red line. g eo lo gi a c ro at ic a geologia croatica 76/276 redness rating index (rr) translates the increase in redness between a soil or palaeosol and its parent material into a numerical value by comparing the changes in hue and chroma (buggle et al., 2014). based on the obtained parameters, ri1 (barron & torrent, 1986; rossel et al., 2006) (equation 1) and rr were calculated (torrent et al., 1983), (equation 2): ri l a b b l 1 102 2 0 5 8 2 6 = + × × ( * * ) * . . , (1) rr h c v = − ×( )10 , (2) where l stands for lightness, a* for green-red colour, b* for blueyellow colour calculated by konica minolta chroma meter cr400, h for hue, c for chroma, and v for value in the munsell colour chart. as previously mentioned, the colour was determined in both dry and wet conditions. their difference was used in the calculation, following the approach by buggle et al. (2014). the indices described above belong to the group of “true” index values, presented by the non-dimensional number. 3. results 3.1. pedostratigraphy and chronostratigraphy the dukatar profile is a section where the oldest sediments on the tlp were discovered and which has a thickness of 10 m (e.g. marković et al., 2012, 2015). both the oldest loess unit (l5) and the oldest exposed pedocomplex (s5) of tlp are observed within this site. for the purposes of this study, the lowest part of the l5 loess unit and the s5 pedocomplex, with a total thickness of approximately 2.7 m, were sampled. the sampled sequence (300 cm thick) extends from the contact between the upper part of the humus accumulating horizon a (~ 20 cm thick) and the basal part of the l5 loess unit. beneath the a horizon there is a well-developed dark brown rubified cambic bw horizon, with moderately developed coarse polyhedral structure that is approximately 110 cm thick (fig. 2b). in the central part of the pedocomplex, s5 is a ck horizon containing many carbonate concretions, and bioturbation caused by roots that are now preserved as rhizoliths. the lower bw is a weakly rubified horizon disturbed by many hydromorphic features. in the bottom part of the pedocomplex s5 there is a horizon containing massive carbonate configure 2. a) the picture of dukatar lps (photo by lukić, t., september 2014) with indicated lithostratigraphy; b) pedostratigraphy of dukatar lps. figure 3. histograms indicating a) l; b) a* chromaticity; c) b* chromaticity; d) the same parameters plotted on the depth scale of dukatar lps. g eologia c roatica 77 cretions overlying loessoid material of alluvial origin (also with numerous hydromorphic forms). the description presented here corresponds well to the previous palaeopedological interpretations put forward by bronger, (1976, 2003), marković et al., 2012, 2015; basarin et al., 2014). chronostratigraphic models of the lpss in serbia, presented by marković et al. (2012, 2015) and basarin et al. (2014), provide correlation between the pedocomplex s5 at the dukatar profile (tlp) with the accepted mis 13-15 s5. marković et al. (2015) indicated a remarkable accordance between danubian and chinese loess records, thus opening up the possibility for a transcontinental correlation of european, central asian and chinese lpss, using a standardised nomenclature and chronostratigraphic model. 3.2. colorimetric and magnetic interpretation the histograms in fig. 3 illustrates the distribution of results for the colorimetric measurements l, a*, and b* parameters from the dukatar profile (s5). based on instrumental colour measurements, marked variations in l colorimetric values were observed. these variations displayed the following ranges: between the bottom part of the l5 unit, and the upper part of the a horizon within the s5 pedocomplex (64-66 units), and the bottom part of the bw horizon, and its contact with ck basal horizon (66-75 units) (fig. 3a and fig. 3d). the lowest values (56) are associated with the bw dark brown horizon, at 150 cm depth. variations are particularly noticeable between 180 and 195 cm from the upper part of the examined section (values vary between 61 and 68 units) and result from the presence of large diameter carbonate concretions that are characteristic of this part of the pedocomplex. again, the values of l increase towards the calcified ck horizon in the basal part of the s5 pedocomplex. the values of a* chromaticity (fig. 3b and fig. 3d) display variation that correspond to the detected variations in l colorimetric values. note that the a* values are mirrored to symmetrically match the l. they range from 3.4 units to 8.2 units at a depth of 15 cm to 120 cm. subsequently, the values gradually decline to a depth of 192 cm, where the lowest value (3.6) was recorded. the a* chromaticity gradually increases to the value of 6.5 units at a depth of 252 cm, and then begins to continuously decline to a depth of 270 cm (2.4), which is the lowest value in the pedocomplex. the highest measured a* values are 8.2 and were recorded in the upper part of the examined section, in the central part of the bw rubified horizon. observations of b* chromaticity (fig. 3c and fig. 3d) display fluctuating values that vary slightly starting from the top to the middle of the examined profile. these values range from 19.5 to 23.9 units. in the transitional part between the l5 unit, and the upper part of the a horizon within the s5 pedocomplex the values rise from 21.6 to 19.8 units (between the bottom part of the bw horizon and its contact with the ck basal horizon). as noted in the previously mentioned colorimetric parameters values, stronger fluctuations in b* chromaticity values are observed in the central part of the s5 pedocomplex. in general, these values gradually increase from the upper part of the pedocomplex to 171 cm, ranging from 21.5 units to 23.9 units, respectively. after this, b* chromaticity values start to gradually decrease towards the value of 21.2 units observed at a ck horizon, at the depth of 192 cm. the b* chromaticity values from this point display continuous fluctuations that are most likely to be the result of the presence of hydromorphic features and carbonate concretions that are common at the basal part of the bw horizon and its contact with the ck horizon. the depth plot of these parameters is presented in fig. 3d. results of the χlf measurements indicate that χlf variations are in good agreement with the pedostratigraphy (fig. 4a). the histogram fig. 4b illustrates the results of χlf for the dukatar profile (s5). values of χlf range from 40×10-8 m3 kg-1 in the upper part up to 132×10-8 m3 kg-1 at a depth of 114 cm. thereafter, the values gradually decline to 43×10-8 m3 kg-1 at a depth of 171 cm, after which they begin to progressively increase to the value of 93×10-8 m3 kg-1, observed at 229 cm from the top of the examined section (fig. 4a). a decrease in the χlf value was identified in the deeper parts of the horizon, with a sharp transition detected at a depth of 270 cm (61×10-8 m3 kg-1) and continuing to the basal part of the profile, where the values of 18×10-8 m3 kg-1 were recorded. the values represent the absolute minimum found on the examined profile. these low χlf values are probably the result of gleization due to variation in underground and surface water levels. the results display very similar variations to those recorded during previous research of lpss in serbia; also to those on the eastern and figure 4. a) the low-frequency magnetic susceptibility measurements (χlf) for the dukatar profile; b) histogram for χlf. g eo lo gi a c ro at ic a geologia croatica 76/278 western coast of the black sea and in central and east asia (china) (e.g. heller & evans, 1995; buggle et al., 2009; buggle et al., 2014; marković et al., 2009, 2012; basarin et al., 2014). in fig. 5 the four panels present the linear and polynomial fit of l and a* with magnetic properties of the s5 pedocomplex. the correlation between the χlf and l of the samples in dukatar is very strong; high values of l correlate to the low values of χlf. this can be explained by the higher concentrations of calcium carbonate (caco3) along some horizons of the pedocomplex, which do not possess fe minerals, and provides the white colour. the coefficient of determination r2 is best expressed as the polynomial fit, and has the value of 0.87. in contrast, the higher a* values correspond to higher χlf, and the trend is steadily rising. the high values of a* present the red colour which most likely comes from ferromagnetic haematite. the r2 value is also fitted better in polynomial case, with the value of 0.97. 3.3. soil developed indices (sdi): rubification (ri) and melanization (mi) indices in moist conditions, the hues determined using a munsell soil colour chart for the first 66 cm of the examined sequence hues, range between 10yr3/6 and 10yr5/6. in the next 90 cm the hues vary from 7.5yr3/4 to 7.5yr4/6; for a depth from 159 cm to 288 cm hues range from 10yr3/4 and 10yr5/6. in the remaining part of the profile, the hue has the value of 2,5y5/6. at the same depths in dry conditions, the values ranged from 2.5y6/4 to 10yr7/4, then from 10yr6/6 to 7.5yr5/6, from 10yr4/6 to 10yr7/4 and 2.5y7/4 respectively. quantified soil development indices (sdi), rubification (ri) and melanization (mi) are shown in fig. 6. the ri shows relatively low variability in the first 57 cm from the upper part of the sampled section. calculated values vary from 10 to 40, with only one extreme value observed at 24 cm (10). from 60 cm to 150 cm figure 5. polynomial amd linear fit of the magnetic susceptibility data χlf, l, and a* for dukatar lps. the y and x in the regression equalions refer to the mentioned parameters. figure 6. the rubification index (ri), melanization index (mi), redness index (ri1), and the redness rating index (rr) for the dukatar lps. g eologia c roatica 79 of the section, ri values progressively increase from 40 to 100. a pronounced decline in values was observed at a depth between 165 cm and 170 cm (90 to 40) which is consistent with measured a* chromaticity values. at a depth of 216 cm of the examined section, ri values gradually decline from 60 to 20. melanization index (mi) in the first 63 cm of the profile is characterized by moderate variations ranging from –10 to –30. thereafter, index values vary from –30 to –50 to a depth of 84 cm. then a progressive decline in values occurs, with –10 being the most extreme one, detected at 171 cm from the top of the profile. at a depth between 171 cm and 258 cm relatively stable mi values (–30) are present. in this part of the section, only one value of –40 was noted (at a depth of 222 cm). from 258 cm, a gradual decrease in values ranging from –30 to –10 was apparent. ri and mi values, obtained through soil sample analysis using a munsell soil colour chart (observed with the naked eye) also largely correspond to the results from measurement of a* chromaticity and l lightness values using a tristimulus colorimeter. 3.4. soil colour proxies: redness (ri1) and redness rating (rr) indices the calculated redness index values (ri1) are shown in fig. 6. values of ri1 that may relate to relative changes in haematite content (barron & torrent, 1986) in the examined pedocomplex, appear to correspond to the detected variations recorded in the signal of χlf (fig. 4a). these values remain relatively low in the top 30 cm of the upper part of the section, and vary between 0.12 and 0.11, presumably indicating a slightly lower haematite content. after this depth, the possible haematite concentration gradually increases to a depth of 126 cm, with a maximum value of 0.30. thereafter, the ri1 values decrease to a depth of 189 cm, where the minimum value was recorded (0.10). the values then gradually increase to a depth of 234 cm from the upper part (0.21), before decreasing again towards the basal part of the sequence. consequently, it can be noted that ri1 values generally correspond to the measured values of l, a*, and b* colorimetric indicators and sdi ri and mi. soil redness rating index (rr) values, associated with the pedostratigraphy of the section are also shown in fig. 6. therefore, ri1 as well as rr indices could reflect the haematite content in the examined dukatar s5 pedocomplex in a semi-quantitative manner. the values appear relatively uniform for the first 78 cm from the upper part of the section and amount to 0, with one exception, observed at 72 cm (7.5). thereafter, the index values increase to a depth of 156 cm, ranging from 7.5 to 11.25. at a depth of 171 cm the values again drop to zero. the basal part of this site is characterized by the highest rr values of 12. soil rr values correspond to a large degree to the values of l, a*, and b* colorimetric indicators, sdi ri and mi and χlf values for the first 156 cm from the top of the examined section. values detected in the second half of the dukatar section at the contact between horizons bw and ck show slightly higher deviations, especially in the basal part. this can be explained by the presence of massive carbonate concretions. 4. discussion 4.1. magnetic susceptibility and colour as indicators of palaeoclimatic and palaeoecological processes at the dukatar pedocomplex s5 studies focused solely on instrumental colour determination of palaeosols are relatively scarce in serbia. the results presented in this study represent the first palaeoclimatic/palaeoecological reconstruction based on colorimetric values of the strongly rubified interglacial s5 pedocomplex, formed in the time frame between mis 13-15 at the dukatar site. the observed changes, from yellowish-brown to reddishbrown, along with the corresponding indices, most likely indicate variations between haematite and goethite concentrations (ji et al., 2004; scheinost & schwertmann, 1999). studies undertaken in china indicate that on the loess plateaus, where soils are generally well drained, haematite and goethite concentration is closely associated with variations in soil temperature and precipitation/humidity. magnetic susceptibility measurement of palaeosols from the chinese loess plateau (clp) indicate palaeo-precipitation variability between 590-1120 mm-1 (sartori et al., 2005). comparable palaeo-precipitation data for the southeastern and central pannonian basin indicates variations of 580 to 650 mm a−1 over a similar timescale (panaiotu et al., 2001; bradák et al., 2011). palaeoclimatic forcing affects the production of pedogenically formed haematite and goethite. kämpf & schwertmann (1983) assert that pedogenic ferrihydrite conversion to haematite is initiated by dehydration in the soil, increasing aridity and/or a sustained increase in temperature. the same research states that unlike haematite, goethite production from ferrihydrite does not display a high degree of sensitivity to temperature change, with its formation being initiated under more humid conditions. therefore, haematite prevalence in relation to goethite rises with an increase in mean annual air temperature, while goethite prevalence is associated with increased soil moisture. based on these characteristics, the utilization of sdi along with magnetic measurements for detection of iron-bearing minerals can serve as a useful tool in lps research. increases in the haematite/ goethite ratio (hm/gt) indicate arid conditions, while lower values are an indicator of more humid conditions (liu et al., 2006). buggle et al. (2014) in their study on quaternary climate change in lpss from south-east europe, presented results obtained by using diffuse reflectance spectroscopy (drs) and colorimetric proxies. these were based on predetermined values from the munsell soil colour chart such as ri1 and rr. the ri1 and the rr rely upon the positive relationship between chroma, and the chroma to lightness ratio, to the total iron oxide content, as well as the power of hue to discriminate between the relative proportions of haematite and goethite (hurst, 1977; buggle et al., 2014). the aforementioned colour proxies in correlation with the χlf values were used to determine the variation in the presence of ferromagnetic minerals in the lpss of batajnica and stari slankamen in serbia, and mircea vodă in romania, as well as the initial results for this study. due to a general lack of absolute dating of lpss, chronostratigraphic models based on the correlation of χlf values on a regional scale, along with deep-sea sediment records, are crucial for the reconstruction of the palaeoclimatic change dynamics (buggle et al., 2009). the stratigraphic model developed for the vojvodina loess, while based upon the chinese loess-stratigraphic system, actually resulted from the systematically conducted research of marković et al. (2004a, b, 2005, 2006, 2007, 2008, 2009, 2011, 2012, 2014, 2015, 2021a). this stratigraphic model, enabled loess units and pedocomplexes to be linked with the corresponding mis for the first time. in general, cyclic fluctuations that occur in the χlf signal correlate well with variations of oxygen isotopes in deep-sea sediments. european stratigraphic members from s0 to s5 are in good agreement with g eo lo gi a c ro at ic a geologia croatica 76/280 stratigraphic members from the clp (lu et al., 1999), corresponding to the mis 1, 5, 7, 9 and 11 interglacials. the thick s5 pedocomplex at dukatar correlates well with mis 13 to 15 (marković et al., 2015). according to its palaeopedological characteristics, this stratigraphic unit must have formed over a longer period of warm and humid climate as it displays elements of more advanced pedogenetic modification than can be found in more recent soils from the region (bronger et al., 1998; bronger, 2003). the results of buggle et al., (2014) also support this assertion. samples from the dukatar s5 pedocomplex display a general increase in the χlf value. this pedogenically conditioned increase in magnetic susceptibility indicates the formation of ferromagnetic minerals. consequently, more investigation is required to clarify pedogenic and palaeoclimatic background of the investigated pedocomplex. a similar increase in s5 pedocomplex χlf values was also observed in the batajnica (marković et al., 2009) and stari slankamen lpss (marković et al., 2011). in fig. 7, all of the parameters and indices from this study are plotted with depth. sampled at a resolution of 3 cm, the obtained χlf values display variations with increasing depth: from the contact between the basal part of loess unit l5 and the upper part of the a horizon, through to the contact between the bottom part of the ck horizon and loessoid material at the base of the exposed part of the profile. the sdis ri and mi, as well as l, a*, and b* colorimetric indicators co vary with the χlf values. measured values of a* chromaticity could be considered as an indicator of the presence of pedogenetic haematite. in addition, these values show a strong correlation with the values of the ri1 (r2=0.91, not shown) at the significance level p<0.01. 4.2. possible relationship between colorimtric indices and ferromagnetic composition 4.2.1. the haematite/goethite model problem iron minerals such as haematite and goethite are significant constituents of most soils, and serve as proxy records of climatic and ecological changes. as has been previously asserted, warm and dry conditions are favourable for the formation of haematite, and lead to its separation from ferrihydrite (fh), while humid conditions are more favourable for the formation of goethite, and lead to its formation by direct excretion from any fe source (ji et al., 2004). soils containing only, or almost exclusively goethite, have yellow colour, whereas in soils rich in haematite the colour is usually reddish, due to the fact that red haematite successfully masks yellow goethite (scheinost & schwertmann, 1999). unfortunately, the haematite/goethite model in loess (e.g. guo et al., 2009; lukić et al., 2014), is not uniformly applicable in all lpss across europe. contrary to this model, zeeden et al. (2015) found haematite present in a loess unit at krems-wachtberg lps. furthermore, at the paks lps the well developed mb and pd2 palaeosols contain significant amounts of pedogenic magnetite and maghemite, but no haematite (bradak et al., 2019). haematite was found both in loess and palaeosols in czech republic (oches & banerjee, 1996). however, in serbia, the study of laag et al. (2021) suggested that tracking the magnetite/maghemite content on its own may not provide a clear enough interpretation of pedogenic processes during the interglacials. they advocated the use of colorimetric data, as it provides direct insight into haematite and goethite content. the same authors revealed that between mis2 and mis11 palaeosols contain relatively higher amounts of haematite compared to goethite. 4.2.2. the significance of rubified fossil soils in lpss as pointed out by numerous international studies colour variations have been used as a proxy for mineral concentrations in lpss (e.g. chen et al., 2002; vidić et al., 2004; lukić et al., 2014; buggle et al., 2014). the reddening of palaeosols is shown to depend of presence of the amount of ferromagnetic minerals such as maghaemite (schwertmann, 1993) and haematite (chen et al., 2002; buggle et al., 2014). lukić et al. (2014) and buggle et al. (2014) pointed out that a* chromatici ty values can be considered to be a proxy for relative abundance of pedogenic haematite similar to ri1 and rr. this pedogenic haematite may also be responsible for the darkening of fossil soils (as shown on clp by chen et al. (2002)) affecting the mi and the l chromaticity values, regardless of soil organic matter content. vidić and lobnik (1997) emphasized that the decrease in mi depends on time, nature and quality of soil organic matter. there are a few cases where the mi obtained in this study does not fully correspond with the other quantified indices at some depths, such as the slight increase in mi in weakly rubified bw horizon. this feature may be attributed to soil components other than organic matter such as mn-mottles. based on these initial findings, soil colour indices represent additional sensitive paleoenvironmental proxies, which, therefore, should be more widely applied in similar investigations including rock magnetic figure 7. all of the calculated parameters and indices for dukatar lps. figure 8. the linear function fitting the redness index (ri1) and low-frequency magnetic susceptibility measurements (χlf) of dukatar lps. g eologia c roatica 81 properties. significant correlation (p<0.01) is observed between ri and mi, wherein higher ri values indicate more intensive red colour, while higher mi values indicate its darkening (r2=0.76, not shown). the dukatar pedocomplex is characterized by the significant presence of carbonates which are excreted from higher horizons and deposited in the central and basal part of the palaeosol s5. the light, whitish colour of the carbonates can be registered through the l values and melanization index (mi) values. this can be particularly well noted in values observed at a depth between 180 and 195 cm from the upper part of the examined section. as mentioned in the previous chapter, combined utilization of parameters for determining rock magnetism and colorimetric studies has a rather good perspective (lukić et al., 2014). 4.2.3. interpretation of the dukatar pedocomplex colorimetric data figure 8. illustrates the significance (p<0.01) of the positive relationship between χlf and ri1 (r2=0.88); indicating that during the middle pleistocene, throughout mis 13-15 (when pedocomplex s5 was formed) conditions were, most likely, favourable for haematite formation. the regression function for the investigated section is y=0.001x+0.032. buggle et al. (2014) noted that the haematite/goethite value ratio (hm/(hm + gt)) increased between the s4 and s5 palaeosols. these results are somewhat in accordance with the presented initial palaeopedological and geochemical indicators which possibly suggest more intensive development and the effect of eluvial processes in older pedocomplexes (buggle et al., 2013). the soil redness index (ri1) of the dukatar s5 pedocomplex corresponds to a large extent with the detected variations recorded in the χlf. therefore, ri1 can be used as a convenient alternative to magnetic susceptibility for generating paleoclimatic data in the loess province of vojvodina (north serbia). the haematite content appears to be higher in the upper part of the examined section, with the highest values occurring between 146 cm and 180 cm. these findings are confirmed by the values of the soil redness rating index (rr). this is in direct contrast to ri1, which, after the calcified part of the profile, displays a continuous decrease in values towards the bottom part of the section. with regard to haematite prevalence, the rr index between 171 cm to 288 cm in the upper part of the profile records values equal to 0. the observed differences between these proxies can be explained by their nature, which uses distinct variables upon which differences in soil redness and haematite content are expressed. it should be noted that the rr index represents a value which, in a semi-quantitative manner, indicates possible haematite content in the soil. the rr index therefore represents a somewhat more conservative method, as the threshold hue used is 7.5yr or greater. in contrast, the ri1 is not limited in terms of colour hue, and therefore can indicate in a more sensitive manner lesser concentrations of ferromagnetic minerals that cannot produce colour values of at least 7.5yr. based upon the soil colour index values recorded at the dukatar section, the use of the ri1 index is deemed to be a more appropriate metric, since this index is more sensitive to lithological changes and soil development intensity (e.g. marković et al., 2009). during future studies of this pedocomplex, diffuse reflectance spectroscopy (drs) should be used in order to determine haematite content in the most precise way possible, as well as haematite and goethite ratios in this pedocomplex. based on findings from buggle et al. (2014), which refer to other s5 pedocomplexes in north serbia, possible palaeoenvironmental conditions could be noted: in common with the batajnica and stari slankamen lpss, the investigated pedocomplex at dukatar was formed during the mis 13-15. it is understood that these stages were characterized by higher summer temperatures and/or longer drought periods. slightly higher temperatures during the winter months (>0 ºc) could serve as an initial explanation for the increased production of haematite in the s5 pedocomplex, since the presence of organic matter hinders its formation. in addition, a marked increase in magnetic particle concentrations in the dukatar s5 pedocomplex can be seen on the χlf plot. likewise, it is worth mentioning that the s5 pedocomplex in a chronostratigraphic context corresponds well with the s5 lithological unit on the clp (fig. 9). the results of χlf for the dukatar pedocomplex and luochuan s5 on the clp (lu et al., 1999) are presented and highlighted on the figure 9. namely, this highly developed pedocomplex (corresponding to the mis 13-15) is used as a stratigraphic marker in central china because of its dark brown-reddish colour (chen et al., 2002; guo et al., 2013; han et al., 1998, lu et al., 1999). based on the studied pedogenetic characteristics, han et al. (1998) assert that the s5 pedocomplex was formed during a period characterized by relatively stable and drier climatic conditions in relation to the climatic conditions during the holocene. according to yin and guo (2008), the existing climatic conditions were spurred by the strengthening of summer monsoon circulation in the northern hemisphere. in addition, the measured values of χlf presented in this study correlate well with research results of other lpss both in the region and on the eurasian continent (buggle et al., 2009; marković et al., 2009, 2012b, 2015). in general, higher χlf values in the s5 pedocomplex on the dukatar profile also indicate a possible reduction in the excess moisture in the soil, which is associated with slightly higher temperatures during the winter months; this results in a reduction in the precipitation/evaporation ratio. the aforementioned interpretations suggest climatic conditions similar to those in the mediterranean, prevailed in the loess region of both the lower and middle danube basin during mis 13-15 (buggle et al., 2014). the prevailing influence of the mediterranean climate on soil formation persists for around 180 km southwards of the investigated dukatar site, as described at the stalać lps. here, a well rubified cambisol was able to form during both mis 9 and mis 7, when the middle danube basin was already experiencing colder, continental climate conditions (obreht et al., 2016). 4.3. comparative views on interglacial palaeoclimatic and palaeoecological conditions during the formation of s1 and s5 pedocomplexes in northern serbia the same methodological approach undertaken for this study was also adopted by lukić et al. (2014) at the orlovat lps (figure 1). as the orlovat and dukatar are the only lpss investigated from a joint rock magnetic and colorimetric perspective in the north part of serbia, the comparison between the sections is presented here. well defined differences in interglacial palaeoclimatic and palaeoecological conditions become apparent when studying palaeosol s1 at the orlovat-brickyard, and pedocomplex s5 dukatar presented in this study (fig. 10). the s1 palaeosol is a strongly developed soil of approximately 400 cm thickness formed during the mis 5 period. the aforementioned thickness indicates higher accumulation rates during the final part of mis 5 and mis 4 (marković et al., 2014). the s1 palaeosol has significantly higher χlf values ranging from 35 to 70 × 10-8m3kg-1 in contrast g eo lo gi a c ro at ic a geologia croatica 76/282 to the l1 loess unit which shows small variations in χlf values (cca. 20 × 10-8m3kg-1). these values gradually increase towards the base of s1, possibly indicating pedogenetic formation of superparamagnetic and single-domain ferromagnetics (lukić et al., 2014). the χlf plot shows high similarity with the corresponding palaeosols at other sites in vojvodina, the carpathian region and in the clp (marković et al., 2009, 2012, 2014). the measured values of a* chromaticity generally follow the χlf values, ri and mi. warmer climatic conditions during the lower eemian are presumably reflected in higher a* chromaticity, ri and mi values at the top of the s1 lithological member. humid episodes, which provided sufficient moisture in the soil, occurred during the late spring and early summer. the existence of a highly differentiated ah horizon, characterized by the accumulation of orfigure 10. the low-frequency magnetic susceptibility measurements (χlf), a* chromaticity, rubification index (ri) and melanization index (mi) for a) orlovat lps (lukić et al., 2014); and b) dukatar lps (covered by this study). figure 9. the normalized magnetic susceptibility of some of the oldest lps in serbia: batajnica (marković et al., 2009), tlp (marković et al., 2012), stari slankamen (marković et al., 2011), and orlovat (lukić et al., 2014) presented on a depth scale and compared to lingtai/zhaojiachuan (sun et al., 2006) and lr04 (lisiecki & raymo, 2005) benthic oxygen isotope record presenting the time scale. mis stages as well as magnetic reversals are presented. note the data from dukatar s5 next to the tlp lps. g eologia c roatica 83 ganic matter supports this conclusion (lukić et al., 2014). in general, this chernozem palaeosol indicates a weakening of pedogenesis from interglacial conditions towards the early glacial period (marković et al., 2012, 2014). the χlf record of dukatar s5 shows variations due to the presence of carbonate concretions and hydromorphic features. based upon the data presented in fig. 10, it can be observed that the concentration of ferromagnetic minerals is significantly higher in the dukatar s5 pedocomplex compared to the s1 in orlovat. significantly higher rubification index values in the s5 pedocomplex indicate the dominance of different pedogenetic conditions to those in which the s1 steppe palaeosol was formed. this finding, to a large extent, coincides with other loess-palaeosol studies in which rubification index values were presented (e.g. vidić et al., 2004; marković et al., 2009, 2011; buggle et al., 2014); all indicate a strongly expressed palaeoclimatic transition from sub-mediterranean to arid continental climatic conditions in this part of europe during the last five glacial-interglacial cycles. the variations in the ri and a* values presented in this study provide further evidence of palaeoclimatic evolution during different phases of pleistocene. compared to the s1 palaeosol, mi has significantly lower values due to the presence of different prevailing palaeoclimatic and palaeoecological conditions during the observed interglacial periods. the study of laag et al. (2021) asserts that that the general climatic trend was characterized by progressively reduced precipitation and air temperature over the last 430 kyr (covering the formation of palaeosols s4 to s1), gradually leading to more arid climate conditions (from sections about 50 km south of the dukatar lps). 5. conclusions the aim of this paper is to present the first reconstruction of palaeoenvironmental and climate variability for the mis13-15 s5 dukatar pedocomplex based on high resolution results of the sdi, colour indicators and proxies, supported by χlf. the observed difference in variations of the soil redness index ri1 appear to be influenced by haematite content in this rubified pedocomplex, whereas it is significantly reduced in the soil redness rating index (rr). based on the presented values of the soil colour index for the dukatar section, it could be noted that the use of the ri1 index is deemed more appropriate, since this index appears more sensitive to lithological changes and soil development intensity, while the rr index is considered a somewhat more conservative method. the ri1 can therefore be considered a more useful palaeoenvironmental proxy, which should be more widely applied in similar multiproxy investigations as a possible tracer of ironbearing minerals. moreover, it should be emphasized the multiproxy approach set out in this study has proved a very favourable methodology for assessing palaeoclimatic and palaeoenvironmental conditions from palaeosols. while the studied indices have confirmed the assertions of earlier studies, regarding the climatic transition from humid mediterranean towards the more arid continental one, more detailed investigation is required to verify precise ferromagnetic contents, their ratio, and correlation to colorimetric perspectives, in order to clarify pedogenic and paleoclimatic context. acknowledgement the authors gratefully acknowledge the financial support of the ministry of science, technological development and innovation of the republic of serbia (grant no. 451-03-47/2023-01/200125). this research was partially funded by the provincial secretariat for higher education and scientific research of autonomous province of vojvodina, republic of serbia (grant no. 142-4512655/2021-01/2). the authors are grateful to đorđije vasiljević and miroslav vujičić for their help during the field work. we confirm that all the authors made an equal contribution to the study and its development. finally, the authors are grateful to the anonymous reviewers whose comments and suggestions greatly improved the manuscript. references banak, a., mandic, o., sprovieri, m., lirer, f. & pavelić, d. (2016): stable isotope data from loess malacofauna: evidence for climate changes in the pannonian basin during the late pleistocene.– quatern. int., 415, 15–24. doi: 10.1016/j. quaint.2015.10.102 banak, a., pavelić, d., kovačić, m. & mandic, o. (2013): sedimentary characteristics and source of loess in baranja (eastern croatia).– aeolian res., 11, 129–139. doi: 10.1016/j.aeolia.2013.08.002 barrón, v. & torrent, j. (1986): use of the kubelka – munk theory to study the influence of iron oxides on soil colour.– j. soil sci., 37/4, 499–510. doi: 10.1111/ j.1365-2389.1986.tb00382.x basarin, b., buggle, b., hambach, u., marković, s.b., dhand, k.o. h., kovačević, a., ... & lukić, t. (2014): time-scale and astronomical forcing of serbian loess–paleosol sequences.– global planet. change, 122, 89–106. doi: 10.1016/j.gloplacha.2014.08.007 berger, g.w., pillans, b.j. & palmer, a.s. (1992): dating loess up to 800 ka by thermoluminescence.– geology, 20/5, 403–406. doi: 10.1130/0091-7613(1992) 020<0403:dlutkb>2.3.co;2 boesken, j., klasen, n., zeeden, c., obreht, i., marković, s.b., hambach, u. & lehmkuhl, f. (2017): new luminescence‐based geochronology framing the last two glacial cycles at the southern limit of european pleistocene loess in stalać (serbia).– geochronometria, 44/1, 150–161. doi: 10.1515/geochr-2015-0062 bradák, b., seto, y., csonka, d., végh, t., & szeberényi, j. (2019): the hematite–goethite enhancement model of loess and an ‘irregular’case from paks, hungary.– j. of quaternary sci. 34/4-5, 299-308. bradák, b., thamó-bozsó, e., kovács, j., márton, e., csillag, g., & horváth, e. (2011): characteristics of pleistocene climate cycles identified in cérna valley loess–paleosol section (vértesacsa, hungary).– quaternary international, 234/1–2, 86–97. doi: 10.1016/j.quaint.2010.05.002 bronger, a. (1976): zur quartären klimaund landschaftsentwicklung des karpatenbeckens auf (paläo) pedologischer grundlage.– habilitationschrift. kieler geographischen schriften, 45, kiel, 1–269. bronger, a. (2003): correlation of loess–paleosol sequences in east and central asia with se central europe: towards a continental quaternary pedostratigraphy and paleoclimatic history.– quatern. int., 106, 11–31. doi: 10.1016/s10406182(02)00159-3 bronger, a., winter, r. & sedov, s. (1998): weathering and clay mineral formation in two holocene soils and in buried paleosols in tadjikistan: towards a quaternary paleoclimatic record in central asia.–catena, 34/1–2, 19–34. doi: 10.1016/ s0341-8162(98)00079-4 buggle, b., hambach, u., glaser, b., gerasimenko, n., marković, s. b., glaser, i. & zöller, l. (2009): stratigraphy and spatial and temporal paleoclimatic trends in east european loess paleosol sequences.– quatern. int., 196, 86–106. doi: 10.1016/j.quaint.2008.07.013 buggle, b., hambach, u., kehl, m., zöller, l., marković, s.b. & glaser, b. (2013): the progressive evolution of a continental climate in se-central european lowlands during the middle pleistocene recorded in loess paleosol sequences.– geology, 41, 771–774. doi: 10.1130/g34198.1 buggle, b., hambach, u., müller, k., zöller, l., marković, s.b. & glaser, b. (2014): iron mineralogical proxies and quaternary climate change in seeuropean loess–paleosol sequences.– catena, 117, 4–22. doi: 10.1016/j.catena.2013.06.012 chen, j., ji, j., balsam, w., chen, y., liu, l. & an, z. (2002): characterization of the chinese loess–paleosol stratigraphy by whiteness measurement.– palaeogeogr. palaeocl., 183/3–4, 287–297. doi: 10.1016/s0031-0182(02)00246-8 fenn, k., millar, i.l., durcan, j. a., thomas, d.s., banak, a., marković, s.b., ... & stevens, t. (2022): the provenance of danubian loess.– earth-science reviews, 103920. doi: 10.1016/j.earscirev.2022.103920 galović, l. (2014): geochemical archive in the three loess/paleosol sections in the eastern croatia: zmajevac i, zmajevac and erdut.– aeolian res., 15, 113–132. doi: 10.1016/j.aeolia.2014.07.004 galović, l. (2016): sedimentological and mineralogical characteristics of the pleistocene loess/paleosol sections in the eastern croatia.– aeolian res., 20, 7–23. doi: 10.1016/j.aeolia.2015.10.007 g eo lo gi a c ro at ic a geologia croatica 76/284 galović, l. & peh, z. (2016): mineralogical discrimination of the pleistocene loess/ paleosol sections in srijem and baranja, croatia.– aeolian res., 21, 151–162. doi: 10.1016/j.aeolia.2016.04.006 guo zt, berger a, yin, qz & qin, l. (2009). strong asymmetry of hemispheric climates during mis‐13 inferred from correlating china loess and antarctica ice records.– clim. past. 5, 21–31. doi: 10.5194/cp-5-21-2009 guo, x., liu, x., li, p., lü, b., guo, h., chen, q., ... & ma, m. (2013): the magnetic mechanism of paleosol s5 in the baoji section of the southern chinese loess plateau.– quatern. int., 306, 129-136. doi: 10.1016/j.quaint.2013.02.033 han, j., fyfe, w. s., & longstaffe, f. j. (1998): climatic implications of the s5 paleosol complex on the southernmost chinese loess plateau.– quaternary res., 50/1, 21–33. doi: 10.1006/qres.1998.1976 harden, j.w. (1982): a quantitative index of soil development from field descriptions: examples from a chronosequence in central california.– geoderma, 28/1, 1–28. doi: 10.1016/0016-7061(82)90037-4 harden, j.w. & taylor, e.m. (1983): a quantitative comparison of soil development in four climatic regimes.– quaternary res., 20/3, 342–359. doi: 10.1016/00335894(83)90017-0 heller, f. & evans, m.e. (1995): loess magnetism.– rev. of geophysics, 33/2, 211–240. doi: 10.1029/95rg00579 hünter lab (2001): hünter lab versus cie 1976 la*b* color scale. insight on color, 1–15. hurst, v.j. (1977): visual estimation of iron in saprolite.– geol. soc. am. bull., 88/2, 174–176. doi: 10.1130/0016-7606(1977)88%3c174:veoiis%3e2.0.co;2 ji, j., chen, j., balsam, w., lu, h., sun, y. & xu, h. (2004): high resolution hematite/goethite records from chinese loess sequences for the last glacial‐interglacial cycle: rapid climatic response of the east asian monsoon to the tropical pacific.– geophys. res. lett., 31/3. doi: 10.1029/2003gl018975 kämpf, n. & schwertmann, u. (1983): goethite and hematite in a climosequence in southern brazil and their application in classification of kaolinitic soils.– geoderma, 29/1, 27–39. doi: 10.1016/0016-7061(83)90028-9 kukla, g. (1987): loess stratigraphy in central china.– quaternary sci. rev., 6/3–4, 191–219. doi: 10.1016/0277-3791(87)90004-7 laag, c., hambach, u., zeeden, c., lagroix, f., guyodo, y., veres, d., ... & marković, s. (2021): a detailed paleoclimate proxy record for the middle danube basin over the last 430 kyr: a rock magnetic and colorimetric study of the zemun loess-paleosol sequence.– front. earth sci., 9, 600086. doi: 10.3389/ feart.2021.600086 liu, q., bloemendal, j., torrent, j. & deng, c. (2006): contrasting behavior of hematite and goethite within paleosol s5 of the luochuan profile, chinese loess plateau.– geophys. res. lett., 33/20. doi: 10.1029/2006gl027172 lu, h., liu, x., zhang, f., an, z. & dodson, j. (1999): astronomical calibration of loess–paleosol deposits at luochuan, central chinese loess plateau.– palaeogeography, palaeoclimatology, palaeoecology, 154/3, 237–246. doi: 10.1016/s00310182(99)00113-3 ludwig, p., gavrilov, m. b., radaković, m. g. & marković, s. b. (2021): malaco temperature reconstructions and numerical simulation of environmental conditions in the southeastern carpathian basin during the last glacial maximum.– j. quaternary sci., 36/8, 1426–1435. doi: 10/1002/jqs.3318 lukić, t., basarin, b., buggle, b., marković, s.b., tomović, v.m., raljič, j.p., ... & gavrilov, m. b. (2014): a joined rock magnetic and colorimetric perspective on the late pleistocene climate of orlovat loess site (northern serbia).– quatern. int., 334, 179–188. doi: 10.1016/j.quaint.2014.03.042 marković, s.b., bokhorst, m.p., vandenberghe, j., mccoy, w.d., oches, e.a., hambach, u., ... & machalett, b. (2008): late pleistocene loess‐paleosol sequences in the vojvodina region, north serbia.– j. quaternary sci.: published for the quaternary research association, 23/1, 73–84. doi: 10/1002. jqs.1124 marković, s.b., gavrilov, b.m., perić, z. & radaković, m. (2021a): лесна палеоземљишта у србији зашто треба чувати земљишне ресурсе, лекције из прошлости. [loess-paleosol sequences in serbia – why should land resources be preserved, lessons from the past – in serbian].– sustainable use of land and water in serbia, 197, 19. marković, s.b., hambach, u., catto, n., jovanović, m., buggle, b., machalett, b., ... & frechen, m. (2009): middle and late pleistocene loess sequences at batajnica, vojvodina, serbia.– quatern. int., 198/1–2, 255–266. doi: 10.1016/j.quaint.2008.12.004 marković, s.b., hambach, u., stevens, t., basarin, b., o’hara-dhand, k., gavrilov, m.m., ... & teofanov, n. (2012a): relating the astronomical timescale to the loess–paleosol sequences in vojvodina, northern serbia.– climate change, 65–78. doi: 10.1007/978-3-7091-0973-1_5 marković, s.b., hambach, u., stevens, t., jovanović, m., o’haradhand, k., basarin, b., ... & zöller, l. (2012b): loess in the vojvodina region (northern serbia): an essential link between european and asian pleistocene environments.– neth. j. geosci., 91/1–2, 173–188. doi: 10.1017/ s0016774600001578 marković, s.b., hambach, u., stevens, t., jovanović, m., o’haradhand, k., basarin, b., ... & zöller, l. (2013): loess in the vojvodina region (northern serbia): an essential link between european and asian pleistocene environments.– netherlands journal of geosciences, 91/1–2, 173–188. doi: 10.1017/s0016774600001578 marković, s.b., hambach, u., stevens, t., kukla, g.j., heller, f., mccoy, w.d., ... & zöller, l. (2011): the last million years recorded at the stari slankamen (northern serbia) loess-palaeosol sequence: revised chronostratigraphy and long-term environmental trends.– quaternary sci. rev., 30/9–10, 1142–1154. doi: 10.1016/j.quascirev.2011.02.004 marković, s.b., kostić, n.s., & oches, e.a. (2004a): paleosols in the ruma loess section (vojvodina, serbia).– rev. mex. cienc. geol., 21/1, 79–87. marković, s.b., mccoy, w.d., oches, e.a., savić, s., gaudenyi, t., jovanović, m., stevens, t., walther, r., ivanišević, p., & galović, z. (2005): paleoclimate record in the late pleistocene loess–paleosol sequence at petrovaradin brickyard (vojvodina, serbia).– geol. carpath., 56, 545–552. markovic, s.b., oches, e.a., gaudenyi, t., jovanovic, m., hambach, u., zöller, l., & sümegi, p. (2004b): palaeoclimate record in the late pleistocene loess-paleosol sequence at miseluk (vojvodina, serbia).– quaternaire, 15/4, 361–368. doi: 10/3406/quate.2004.1781 marković, s.b., oches, e.a., mccoy, w.d., frechen, m., & gaudenyi, t. (2007): malacological and sedimentological evidence for “warm” glacial climate from the irig loess sequence, vojvodina, serbia.– geochemistry, geophysics, geosystems, 8/9. doi: 10.1029/2006gc001565 marković, s. b., oches, e. a., perić, z. m., gaudenyi, t., jovanović, m., sipos, g., ... & gavrilov, m. b. (2021b): the požarevac loess–paleosol sequence: a record of increased aridity in the south‐eastern margin of the carpathian basin during the last 350 ka. –j. quaternary sci., 36/8, 1436–1447. doi: 10.1002/ jqs.3327 marković, s.b., oches, e., sümegi, p., jovanović, m. & gaudenyi, t. (2006): an introduction to the middle and upper pleistocene loess–paleosol sequence at ruma brickyard, vojvodina, serbia.– quatern. int., 149/1, 80–86. doi: 10.1016/j.quaint.2005.11.020 marković, s.b., stevens, t., kukla, g.j., hambach, u., fitzsimmons, k.e., gibbard, p., ... & svirčev, z. (2015): danube loess stratigraphy – towards a pan-european loess stratigraphic model.– earth-science reviews, 148, 228–258. doi: 10.1016/j.earscirev.2015.06.005 marković, s. b., timar‐gabor, a., stevens, t., hambach, u., popov, d., tomić, n., ... & gavrilov, m. b. (2014): environmental dynamics and luminescence chronology from the orlovat loess–palaeosol sequence (vojvodina, northern serbia).– j. quaternary sci., 29/2, 189–199. doi: 10.1002/jqs.2693 marković-marjanović, j. (1950): contribution to the geological structure of titel loess plateau. [prilog za geološku građu titelskog brega – in serbian].– zbornik radova geološkog instituta sanu, beograd, 3/1, 91–121. marković-marjanović, j. (1965): a review of the loess problems of yugoslavia in the time of jovan cvijić and today. [osvrt na poznavanje lesnih problema jugoslavije u doba jovana cvijića i danas – in serbian].– bulletin of the serbian geographical society, 45, 2, 99–113. marsigli, a.f. (1726): danubius pannonico mysicus. p. grosse, chr. alberts, p de hoodt haga, herm. uytwert and franc changuion amsterdamus. namier, n., gao, x., hao, q., marković, s. b., fu, y., song, y., ... & guo, z. (2021): mineral magnetic properties of loess–paleosol couplets of northern serbia over the last 1.0 ma.– quaternary res., 103, 35–48. doi: 10.1017/qua.2021.41 nettleton, w.d., olson, c.g. & wysocki, d.a. (2000): paleosol classification: problems and solutions.– catena, 41/1–3, 61–92. doi: 10.1016/s03418162(00)00109-0 obreht, i., buggle, b., catto, n., markovič, s.b., bösel, s., vandenberghe, d.a., ... & jović, g. (2014): the late pleistocene belotinac section (southern serbia) at the southern limit of the european loess belt: environmental and climate reconstruction using grain size and stable c and n isotopes.– quatern. int., 334, 10–19. doi: 10.1016/j.quaint.2013.05.037 obreht, i., zeeden, c., hambach, u., veres, d., marković, s.b., bösken, j., ... & lehmkuhl, f. (2016): tracing the influence of mediterranean climate on southeastern europe during the past 350,000 years.– sci. rep-uk, 6/1, 1–10. doi: 10.1038/srep36334 oches, e.a. & banerjee, s.k. (1996): rock‐magnetic proxies of climate change from loess‐paleosol sediments of the czech republic.– studia geophysica et geodætica. 40, 287–300. doi: 10.1007/bf02300744 panaiotu, c.g., panaiotu, e.c., grama, a., & necula, c., (2001): paleoclimatic record from a loess–paleosol profile in southeastern romania.– physics and chemistry of the earth (a) 26, 893–898. doi: 10.1016/s1464-1895(01)00138-7 pavić, d. (2006): potamological characteristics of the tisza in serbia and predispositions for the development of nautical tourism. [potamološke karakteristike tise u srbiji i predispozicije za razvoj nautičkog turizma – in serbian].– phd thesis, faculty of science, university of novi sad, 343 p. g eologia c roatica 85 perić, z., adolphi, e.l., stevens, t., újvári, g., zeeden, c., buylaert, j.p., ... & gavrilov, m.b. (2019): quartz osl dating of late quaternary chinese and serbian loess: a cross eurasian comparison of dust mass accumulation rates.– quatern. int., 502, 30–44. doi: 10.1016/j.quaint.2018.01.010 popovics, a.b. (1876): jelentés a fruscagora hegysében tett geológiai gyüjtés és kutatásról – ii üledékes közetek.– földtani közlöny, budapest, 286–301. pötter, s., veres, d., baykal, y., nett, j.j., schulte, p., hambach, u., & lehmkuhl, f. (2021): disentangling sedimentary pathways for the pleniglacial lower danube loess based on geochemical signatures.– front. earth sci., 9, 150. doi: 10.3389/feart.2021.600010 radaković, m.g., gavrilov, m.b., hambach, u., schaetzl, r.j., tošić, i., ninkov, j., ... & marković, s.b. (2019): quantitative relationships between climate and magnetic susceptibility of soils on the bačka loess plateau (vojvodina, serbia).– quatern. int., 502, 85–94. doi: 10.1016/j.quaint.2018.04.040 rossel, r.v., minasny, b., roudier, p., & mcbratney, a.b. (2006): colour space models for soil science.– geoderma, 133/3–4, 320–337. doi: 10.1016/j.geoderma.2005.07.017 rubinić, v., galović, l., lazarević, b., husnjak, s. & durn, g. (2018): pseudogleyed loess derivates–the most common soil parent materials in the pannonian region of croatia.– quatern. int., 494, 248–262. doi: 10.1016/j.quaint. 2017.06.044 šarić, j. (2008): paleolithic and mesolithic finds from profile of the zemun loess.– starinar, 58, 9–27. sartori, m., evans, m.e., heller, f., tsatskin, a. & han, j. m. (2005): the last glacial/interglacial cycle at two sites in the chinese loess plateau: mineral magnetic, grain-size and 10be measurements and estimates of palaeoprecipitation.– palaeogeography, palaeoclimatology, palaeoecology, 222/1–2, 145–160. doi: 10.1016/j.palaeo.2005.03.013 schaetzl, r. & anderson, s. (2005): soil genesis and profile differentiation.– in: soils: genesis and geomorphology. new york: cambridge, 347–461. schatz, a.k., zech, m., buggle, b., gulyás, s., hambach, u., marković, s.b., ... & scholten, t. (2011): the late quaternary loess record of tokaj, hungary: reconstructing palaeoenvironment, vegetation and climate using stable c and n isotopes and biomarkers.– quatern. int., 240/1–2, 52–61. doi: 10.1016/j. quaint.2010.10.009 scheinost, a.c. & schwertmann, u. (1999): color identification of iron oxides and hydroxysulfates: use and limitations.– soil sci. soc. am. j., 63/5, 1463–1471. doi: 10.2136/sssaj1999.6351463x schwertmann, u. (1993): relations between iron oxides, soil color, and soil formation.– soil color, 31, 51–69. doi: 10.2136/sssaspecpub31.c4 sgrs (2012): official gazette of the republic of serbia, decree on the proclamation of a special nature reserve “titel loess plateau” [službeni glasnik rrepublike srbije, uredba o proglašenju specijalnog rezervata prirode “titelski breg” – in serbian], 56. sheth, h.c., johnson, c. p., & ollier, c.d. (2010): the “seven-coloured earth” of chamarel, mauritius.– j. afr. earth sci., 57/1–2, 169–173. doi: 10.1016/j. jafrearsci.2009.07.009 sprafke, t., schulte, p., meyer-heintze, s., händel, m., einwögerer, t., simon, u., ... & terhorst, b. (2020): paleoenvironments from robust loess stratigraphy using high-resolution color and grain-size data of the last glacial kremswachtberg record (ne austria).– quaternary sci. rev., 248, 106602. doi: 10.1016/j. quascirev.2020.106602 sümegi, p., gulyás, s., molnár, d., sümegi, b.p., törőcsik, t., almond, p.c., ... & koloszár, l. (2019): periodicities of paleoclimate variations in the first high-resolution non-orbitally tuned grain size record of the past 1 ma from sw hungary and regional, global correlations.– aeolian res., 40, 74–90. doi: 10.1016/j. aeolia.2019.07.002 sun, y., clemens, s.c., an, z., & yu, z. (2006): astronomical timescale and palaeoclimatic implication of stacked 3.6-myr monsoon records from the chinese loess plateau.– quaternary sci. rev., 25/1–2, 33–48. doi: 10.1016/j.quascirev.2005.07.005 taylor, e.m. (1988): instructions for the soil development index template: lotus 1-23 (no. usgs-ofr-88-233). us geological survey, denver, co (united states). timar-gabor, a., panaiotu, c., vereș, d., necula, c. & constantin, d. (2017): the lower danube loess, new age constraints from luminescence dating, magnetic proxies and isochronous tephra markers.– in: landform dynamics and evolution in romania. springer, cham, 679–697. doi: 10.1007/978-3-319-325897_29 torrent, j., schwertmann, u., fechter, h. & alferez, f. (1983): quantitative relationships between soil color and hematite content.– soil sci., 136/6, 354–358. doi: 10.1097/00010694-198312000-00004 vandenberghe, j. (2013): grain size of fine-grained windblown sediment: a powerful proxy for process identification.– earth-science reviews, 121, 18–30. doi: 10.1016/j.earscirev.2013.03.001 vasiljević, d.a., marković, s.b., hose, t.a., ding, z., guo, z., liu, x., ... & vujičić, m. d. (2014): loess–palaeosol sequences in china and europe: common values and geoconservation issues.– catena, 117, 108–118. doi: 10.1016/j. catena.2013.06.005 vasiljević, d.a., marković, s.b., hose, t. a., smalley, i., basarin, b., lazić, l. & jović, g. (2011): the introduction to geoconservation of loesspalaeosol sequences in the vojvodina region: significant geoheritage of serbia.– quatern. int., 240/1–2, 108–116. doi: 10.1016/j.quaint.2010.07.008 vidic, n. j. & lobnlk, f. (1997): rates of soil development of the chronosequence in the ljubljana basin, slovenia.– geoderma, 76/1–2, 35–64. doi: 10.1016/s00167061(96)00098-5 vidić, n.j., singer, m.j. & verosub, k.l. (2004): duration dependence of magnetic susceptibility enhancement in the chinese loess–palaeosols of the past 620 ky.–palaeogeogr., palaeoclim. paleoeco., 211/3–4, 271–288. doi: 10.1016/j.palaeo.2004.05.012 višnić, t., spasojević, b. & vujičić, m. (2016): the potential for geotourism development on the srem loess plateau based on a preliminary geosite assessment model (gam).– geoheritage, 8/2, 173–180. doi: 10.1007/s12371-015-0149-9 vujičić, m.d., vasiljević, d.a., marković, s.b., hose, t.a., lukić, t., hadžić, o. & janićević, s. (2011): preliminary geosite assessment model (gam) and its application on fruška gora mountain, potential geotourism destination of serbia.– acta geogr. slov., 51/2, 361–376. doi: 10.3986/ags51303 lisiecki, l.e. & raymo, m.e. (2005): a pliocene‐pleistocene stack of 57 globally distributed benthic δ18o records.– paleoceanography, 20/1. doi: 10.1029/2004pa001071 wacha, l., laag, c., grizelj, a., tsukamoto, s., zeeden, c., ivanišević, d., ... & frechen, m. (2021): high-resolution palaeoenvironmental reconstruction at zmajevac (croatia) over the last three glacial/interglacial cycles.– palaeogeogr., palaeocl., 576, 110504. doi: 10.1016/j.palaeo.2021.110504 yin, q.z. & guo, z.t. (2008): strong summer monsoon during the cool mis-13.– clim. past, 4/1, 29–34. doi: 10.5194/cp-4-29-2008 zeeden, c., hambach, u., händel, m. (2015): loess magnetic fabric of the krems‐wachtberg archaeological site.– quatern. int., 372, 188–194. zhang, w., lu, h., li, c., dodson, j., & meng, x. (2017): pollen preservation and its potential influence on paleoenvironmental reconstruction in chinese loess deposits.– rev. palaeobot. palyno., 240, 1–10. doi: 10.1016/j.revpalbo.2017.01.002 zykina, v.s., zykin, v.s., volvakh, a.o., radaković, m.g., gavrilov, m.b. & marković, s.b. (2020): late pleistocene loess-paleosol sequence at the belovo section, south of western siberia, russia: preliminary results.– quatern. int., 620, 75–84. doi: 10.1016/j.quaint.2020.10.069 2022 | 75/2 | 199–209 | 5 figs. | 2 tabs. | 2 pls. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the first report on the intrasudetic basin by zobel & carnall (1831-1833) recognized its basin structure but could only differentiate the carboniferous and permian using the presence of grey and red sediments. developing a clear stratigraphy for the intrasudetic basin took a long time (krejčí, beyrich, jokély, o. feistmantel, stur and weiss), and most of these works concerned the carboniferous “coal-bearing” deposits. individual plant species were described from the permian deposits: e.g., autunia conferta (sternberg) kerp (sternberg, 1825), or taeniopteris coriacea göppert and t. falax göppert (göppert, 1864/1865), but a full monograph of the intrasudetic basin permian flora has still to be written. since göppert (1864-1865), the permian flora of the eastern part of the intrasudetic basin has not been systematically studied. němejc (1953) mentioned a list of 10 species from the localities olivětín, otovice and ruprechtice, (broumov formation, olivětín member). interest in the intrasudetic basin increased in the 1960s due to geological mapping, and rieger (1966) listed 22 species from the olivětín member (in tásler et al., 1966). šetlík in tásler et al. (1979) gave essentially the same list as in němejc (1953). bors (1988) was the last researcher who studied the olivětín member flora in detail and expanded the floral list by six species, but the first author regards some of them as questionable. in the polish part of the intrasudetic basin, the flora has been documented by lipps (1927) from the permian locality unisław śląski (langwaltersdorf). collections of the national museum in prague, the east bohemian museum in hradec králové (s. štamberg collection), the museum of wroclaw university (göppert’s collection) and the czech geological survey in prague, have yielded more than 30 biological species from the olivětín member. seeds, fructifications and most of göppert’s collection need to be revised. new flora from the permian of the intrasudetic basin, poland zbyněk šimůnek1 and izabela ploch2 1 czech geological survey, klárov 3/131, 118 21 praha 1, czech republic 2 polish geological institute – national research institute, regional geology department, 4 rakowiecka st., 00-975 warszawa, poland doi: 10.4154/gc.2022.18 abstract a floral assemblage was collected from a new polish locality (janików) situated on the czechpolish border in the intrasudetic basin. it was found in the lower permian (asselian) ruprechtice horizon, of the olivětín member, broumov formation. the plant fossils were usually fragmentary, and the following taxa were determined: alloiopteris aff. erosa, nemejcopteris feminaeformis, senftenbergia sp., lobatopteris sp., sphenopteris sp., cyathocarpus cf. densifolius, lobatopteris cf. geinitzii, lobatopteris nov. sp., dicksoniites cf. plukenetii, autunia conferta, cordaites sp. and seeds. alloiopteris was first recorded in the permian. the assemblage is composed predominantly of ferns and pteridosperms that tend to be hygrophilous to mesophilous floral elements. the flora from the otovice and ruprechtice horizons is usually rich in walchian conifers and peltasperms (autunia conferta), and so the janików flora is quite different with its hygrophilous elements. the fragmentary preservation suggests long transport distances, and probably only the remains of flora growing on the lakeshore were deposited in the calcareous bituminous shales. this coastal vegetation probably formed a barrier to mesophilous plants growing further from the lake, so their fragments are more sporadic. palynology of the olivětín member was recently published by bek and opluštil (2021), who compiled data of kaiserová-kalibová (in tásler et al. 1979). palynology of the polish part of the intrasudetic basin was published by jerzykiewicz (1987) from the stephanian and early permian. the assemblage of the upper anthracosia shale is approximately time eqivalent with the bečkov member in the czech part of the intrasudetic basin. 2. material and methods all the material came from the janików locality, which is situated on the right side of the božanov creek at the polish/czech border (n: 50,545131°; e: 16,400102°). the specimens are now in the collections of the czech geological survey, numbers zš 856 – zš 875. the studied outcrop belongs to the ruprechtice horizon, olivětín merber, broumov formation of the early permian (asselian) age. all the fossils came from a bituminous mudstone layer, which has been divided into five layers, from top to bottom labelled a, b, c, d and e. the strata were poor in plant fossils, and the specimens were collected from fallen blocks of rocks the exact stratigraphical position of which was unknown. the rocks were split using chisels and a hammer, and each specimen was then determined, labelled and quantitatively evaluated. a total rock area of about 2 m2 was used for collecting the fossils. the botanical system according to cleal and thomas (1995) was used in this paper. 3. geological setting the intrasudetic basin is situated along the eastern margin of a suite of late palaeozoic bohemian continental basins (fig. 1) and covers an area of ca. 1800 km2. it has an infill of up to 5 km of middle viséan to triassic strata with several hiatuses. the viséan consists of a few kms of fluvial and alluvial-fan deposits with intercalated marine to deltaic intervals (tásler et al., 1979, article history: manuscript received january 03, 2021 revised manuscript accepted march 24, 2022 available online june 23, 2022 keywords: permian, intrasudetic basin, poland, flora, alloiopteris g eo lo gi a c ro at ic a geologia croatica 75/2200 bossowski, 1995). they are overlain by serpukhovian (early namurian) fluvial and coal-rich deposits of the wałbrzych formation. the depositional centre extended further to the south in the bashkirian. the žacléř formation (late bashkirian–early moscovian; yeadonian–bolsovian) contains 60–80 coal seams in three members. the kasimovian (cantabrian to saberian) is represented by the odolov formation that contains locally important coal seams of the svatoňovice (cantabrian) and jívka (saberian) formations (table 1). the saberian was defined by wagner and álvarez-vázques (2010) as a lower part of the former stephanian b. this concept was accepted by opluštil et al. (2016) and this term is widely used in the literature, even if it was not formally approved. the stephanian/permian chvaleč formation (the equivalent of the krajanów formation in the polish part) is mostly composed of coal-barren fluvial red beds and contains only one thin coal seam in the vernéřovice member (ludwikowice fm.). lacustrine horizons, a few tens of metres thick, with bituminous limestones and shales are rarely intercalated in the red beds (bečkov horizon – krajanów formation in polish part). the overlying broumov formation (the equivalent of the słupiec formation in polish part) contains the nowa ruda, olivětín and martínkovice members that correspond mainly to the asselian (opluštil et al. 2016). the nowa ruda member (“building sandstones” in polish part) is formed chiefly by thick complexes of rhyolite tuffs and tuffites, the olivětín member (“walchia shales” in the polish part) contains up to several tens of metres thick mudstones with thin fossiliferous so-called “walchia”shales and lacustrine bituminous shales and ruprechtice and otovice limestones. the martínkovice member also contains limestone horizons, but only animal fossils have been discovered. the upper permian trutnov (represented by the radków formation in the polish part) and the bohuslavice formations are composed of red and brown mudstone and sandstone deposits, and the middle triassic bohdašín formation is represented mainly by white sandstones. 3.1. description of the fossiliferous section the ruprechtice limestone in its type area in the vicinity of ruprechtice is a light grey, greenish, pinkish or mauve, heavy-bedded or slab-like limestone, passing into laminated marlstone in its upper part. probably only autunia conferta is known from this limestone in this area (rieger, 1966). the ruprechtice limestone also occurs further east, at otovice, where tasler et al. (1977) described it as a dark grey limestone with a bituminous development. rieger (1966) pointed out that ruprechtice and otovice limestones are very similar in the otovice area and the de facto floras from those limestones are difficult to distinguish. table 1. stratigraphic table of the youngest part of the intrasudetic basin. adopted according to opluštil et al. (2016) and šimůnek (2019). remark: time intervals of the gaps between younger units are not known. global scale regional scale czech lithostratigraphic units polish lithostratigraphic units ** formation member formation member tri. middle bohdašín “red sandstones” —246 hiatus pe rm ia n ?lopingian? zechstein bohuslavice hiatus hiatus guadalupian rotliegend trutnov radków chełmsko śląskie wambierzyce cisuralian hiatus asselian* broumov martínkovice słupiec “walchia shales” olivětín nowa ruda “building sandstones” chvaleč bečkov krajanów “upper anthracosia shales” pe nn sy lv an ia n gzhelian stephanian c vernéřovice ludwikowice “lower anthracosia shales” kasimovian b hiatus saberian odolov jívka barruelian “žaltman arkoses” key: tri. triassic, * stage of global scale, studied locality ** correlation with bohemian part according to spudil in pešek et al. (2001) figure 1. a map showing the position of the intrasudetic basin along the czechpolish border. the janików locality is just at the border marked by an arrow. g eologia c roatica šimůnek and ploch: new flora from the permian of the intrasudetic basin, poland 201 however, generally, all museum collections came from the otovice horizon because the classical localities “otovice (ottendorf)” were situated along the stěnava river and černý (black) creek. the janików section consists essentially of tuffs and marlstones. the lowest part of the studied outcrop consists of dark, locally brown, silty tuff, altered by penetrating silica, possibly of volcanic origin. this rock also contains altered volcanic glass. the original structures are not traceable due to later alteration. the total thickness of this bed is unknown. the water level of the stream restricted excavation of the deeper part of the outcrop, thus only 1,5 metres is reported here. the altered tuff is overlain by a dark, bituminous, calcareous shale, ca. 0.60 m thick, with plant fragments and a rich fish fauna; the fossil flora is presented in this article. the shale bed is overlain by 10 cm of mudstone, which is terminated by an uneven erosion surface. above this erosion surface, there is a layer of light creamy rhyolitic tuff blocks, up to 1 m thick. in the outcrop of the watercourse flowing into the bożanowski stream, a higher part of the mudstone bed with tetrapod footprints clearly indicates that the water reservoir was shallowing. 4. systematics 4.1. class filicopsida (ferns) order marattiales engler et prantl family psaroniaceae unger 4.1.1. genus cyathocarpus weiss, 1869 representatives of marattiales have been traditionally assigned to the fossil-genus pecopteris brongniart. however, cleal (2015) pointed out that the type species of pecopteris, pecopteris pennaeformis, belongs to the fossil-genus senftenbergia schimper of the order botryopteridales. so, as a genus cannot belong to more than one family and order, cleal (2015) assigned the other species traditionally accommodated in pecop­ teris to various other fossil-genera. the following species should be transferred to the genus cyathocarpus weiss in the sense of mosbrugger (1983). 4.1.1.1. cyathocarpus cf. densifolius (göppert) comb. nov. (pl. 1, figs. i–k) 1864 cyatheithes densifolius göppert, p. 120, pl. 17, figs. 1, 2. 1890 pecopteris (asterotheca?) densifolia (göppert) zeiller, p. 54–58, textfigs. 27, 28, pl. 7, fig. 3. description: only three fragments of this species have been observed at the janików locality. although they are only small pinnule fragments, they have the typical pinnule shape and venation that determine them. the pinnules have rounded apices; the fragment on pl. 1, fig. k represents the apical part of a pinna of the last order with terminal pinnule and two small pinnules still basally fused. they are only 4 mm long and 3 mm wide. on the other hand, the specimen on pl. 1, fig. j represents the biggest pinnule, which might have been 11.5 mm long and 5 mm wide; the pinnule shown on pl. 1 fig. i was probably of the same width. the venation is common for all samples, with lateral veins arising obliquely from the midrib and fork once or twice dichotomously. remarks: according to němejc (1948), cyatheithes den­ sifolius göppert, 1864, is conspecific with filicites oreopterid­ ius schlotheim, 1804. however, filicites oreopteridius was published before the starting point of 1820 and is considered as nom. illegit. and so, the correct species epithet should be densi­ folius. cleal (2015) argued that cyatheites was a confused genus that had not been clearly typified and should be rejected. as the species belongs to the better-defined cyathocarpus, we propose the new combination cyathocarpus densifolius. 4.1.2. genus lobatopteris wagner, 1959. 4.1.2.1. lobatopteris cf. geinitzii (gutbier) wagner (fig. 5a, pl. 1, fig. h) 1864/1865 asterocarpus geinitzi gutbier: göppert, p. 128– 129, pl. 8, fig. 8. 1983 lobatopteris geinitzii (von gutbier) emend. sterzel) comb. nov., wagner. p. 138–146, pl. 1, figs. 1–4, pl. 3, figs. 1a, 2a, 10. pl. 4, figs. 3a, 10b, 11, 11a. 2009 lobatopteris geinitzii (gutbier) wagner: barthel, p. 50–51, teil 3, figs. 99–102. description: only a small questionable fragment has been discovered in layer c, representing part of a last order pinna with four pinnules (pl. 1, fig. h). the pinnules are 3.5–4 mm long and about 3 mm wide, and the apex is nearly rounded. a thin vein enters each pinnule and divides forming a “lobatopterid” vein pattern. remarks: this small fragment is compared with lobatopte­ ris geinitzii as figured by barthel (2009, fig. 100b). lobatop­ teris geinitzii was mentioned also by göppert (1864/1865) as asterocarpus geinitzi from “oelberg bei braunau” (olivětín u broumova). němejc (1940) placed pecopteris crenulata brongniart as figured by potonié (1893) into his new species asterotheca thuringiaca. barthel (2009) synonymised both species with lobatopteris geinitzii. barthel (1976) published similar specimens under the name pecopteris polypodioides (presl in sternberg) němejc and compared his permian material with bohemian type material of pecopteris polypodioides from the asturian. pecopteris polypodioides was transferred to lobatopteris wagner by knight (1983) – lobatopteris polypodioides (presl in sternberg) knight, 1983. němejc (1940) studied asturian, late stephanian and permian specimens named as pecop­ teris polypodioides and found out that the stephanian and permian ones have markedly smaller pinnules than the asturian ones, even if their shape and venation was similar. barthel (1980b) also named the permian specimens as pecopteris poly­ podioides (presl in sternberg) němejc, but later barthel (2009) detrermined the permian representatives to lobatop­ teris geinitzii (von gutbier, emend. sterzel) wagner. 4.1.2.2. lobatopteris sp. nov. (pl. 1, fig. f, g) ?1927 pecopteris nov. spec. lipps, p. 578, p. 28, fig. 2, 2a. 1990 pecopteris polypodioides (sternberg): šimůnek et al., p. 28–29, pl. 29, figs. 4 and 5. description: this species is relatively common in sub-layers b, c, d, e at the janików locality. only incomplete last order pinnae are preserved, up to 16 mm long and 4 mm wide (pl. 1, fig. g). the latter specimen has small, relatively wide pinnules, 1.5– 2.2 mm long and 1.5–2 mm wide, of oval shape and attached to the rachis by their whole base. a smaller pinna (pl. 1, fig. f) is only 8 mm long and 3.5 mm wide, with pinnules about 1.5 mm long and 1 mm wide. the pinnule apex is always rounded. the venation is poorly visible; the midrib is not seen. it looks like a thin vein enters and forks into several veins in the pinnule. remarks: similar specimens have been figured by barthel (1976, e.g. pl. 16, fig. 10) under the name pecopteris poly­ podioides from the permian of the döhlen basin, germany. the g eo lo gi a c ro at ic a geologia croatica 75/2202 rich barthel (1976) material shows the variability of the pinnules in different parts of the frond. although of comparable size, lobatopteris sp. has better individualised, non-lobed pinnules than the pecopteris polypodioides documented by barthel (1976), i.e., lobatopteris geinitzii. in our opinion, this lobatopteris sp. is a new species comparable with pecopteris nov. sp. of lipps (1927) and is conspecific with specimens from the permian of the krkonoše piedmont basin described by šimůnek et al. (1990) as pecopteris poly­ podioides. 4.2. systematic position uncertain 4.2.1. sphenopteris sp. several specimens have been classified as sphenopteris sp. (table 1). these specimens represent fragments of sphenopteroid pinnules but are not determinable to species. 4.3. order zygopteridales emberger (coenopteridales) family zygopteridaceae p. bertrand ex b. sahni 4.3.1. genus alloiopteris h. potonié 4.3.1.1. alloiopteris aff. erosa (gutbier) sterzel (fig. 5b, pl. 1, fig. a) 1978 alloiopteris erosa (gutbier) sterzel: boersma, p. 58, pl. xi, figs. 1, 2. 2004 alloiopteris erosa gutbier: galtier , p. 213, fig. 4, pl. 7, figs. 1–4, description: only four specimens from janików has been identified as alloiopteris aff. erosa, all in sub-layer b. the most complete fragment is 19 mm long and 3 mm wide (fig. 5b, pl. 1, fig. a) and is a last order pinna. the smaller fragments are as little as 7 mm long and 2.5 mm wide. the pinnules are small and partly fused (fig. 5b). the pinnule margin is irregular with lobes, and thus it is gibbous (fig. 5b, pl. 1, fig. a). the venation is not prominent and was probably rarely forked, although this is mostly not visible on the specimens. remarks: alloiopteris is rarely found in deposits younger than westphalian. boersma (1978) mentioned the range of al­ loiopteris erosa as being from the asturian (“westphalian d”) to the barruelian (“stephanian a”). němejc (1958) mentioned alloiopteris cf. angustissima (sternberg) from the saberian (“stephanian b”) radvanice coal seams. the first author collected alloiopteris similar to alloiopteris erosa before the closing of the kateřina ii coal mine in radvanice, intrasudetic basin. galtier (2004) described alloiopteris erosa from the stephanian b as the youngest representative of this genus. now, we have similar specimens in the permian (asselian) of the intrasudetic basin. 4.3.2. nemejcopteris barthel, 1968 4.3.2.1. nemejcopteris feminaeformis (schlotheim ex sterzel) barthel (pl. 1, figs. b, c) 1820 filicites feminaeformis schlotheim, p. 307. 1968 nemejcopteris feminaeformis (schlotheim) comb. nov.; barthel, p. 733, pl. 1–4, figure 2. detail of the geological map of the broumov permian with the janików locality. (orig. tásler et al. (1966). g eologia c roatica šimůnek and ploch: new flora from the permian of the intrasudetic basin, poland 203 2016 nemejcopteris feminaeformis (schlotheim ex sternberg) barthel; barthel, p. 151, figs. 85– 91, 92a. description: only last order pinna fragments with two to 18 pinnules are preserved in lengths up to 20 mm. the pinnules are triangular with dentate margins, usually 4–7 mm long and 2–3 mm wide. the pinnules are basally fused. the venation is simple, pinnate. straight lateral veins arise at sharp angles from the midrib and end in teeth on the margin. remark: this species is typical by its pinnule shape and is easily distinguished from other zygopterid species. in central bohemia, it is known mainly in saberian (stephanian b) deposits of the mšec and hředle members of a lake or deltaic origin. it is a similar situation in janików. nemejcopteris feminaeformis figure 3. section through the outcrop in janików and images for comparison. g eo lo gi a c ro at ic a geologia croatica 75/2204 was studied in detail by barthel (1968, 1976, 1980a, 2009, 2016). barthel’s nemejcopteris feminaeformis specimens come from germany, and they are of the same age as specimens from the janików locality. 4.4. order filicales engler et prantl family tedeleaceae eggert et t.n. taylor (incl. senftenbergiaceae reed) 4.4.1. genus senftenbergia corda. 4.4.1.1. senftenbergia sp. (pl. 1, figs. d, e) description: senftenbergia sp. is not common in the janików locality in sub-layer c. the larger fragment is 17.5 mm long and 4.8 mm wide (pl. 1, fig. e). the pinnules are small, from 1 to 2.5 mm long and 1 to 2 mm wide. their shape is triangular with crenulated margins and a nearly pointed apex. the second specimen (pl. 1, fig. d) is a small fragment of a bigger frond. the pinnules are 4 mm long, basally fused. the venation is rare; the veins usually obliquely grow from the midrib. remarks: only small fragments have been found, and therefore, it is difficult to determine them. the most widespread species is senftenbergia plumosa. even if it was also mentioned from the stephanian and permian, it is most common in the westphalian. several similar species are known from the permian: e.g., senftenbergia saxonica barthel (1976) and dactylotheca elaverica (zeiller) barthel. sphenopteris mathetii zeiller (barthel, 2009, fig. 156) is another similar species. pteridosperms 4.5. order callistophytales rothwell family callistophytaceae stidd et j.w. hall 4.5.1. genus dicksoniites schlotheim ex sternberg. 4.5.1.1. dicksoniites cf. plukenetii (schlotheim ex sternberg) sterzel (pl. 1, fig. l) description: only tiny fragments of pinnae were found (pl. 1, fig. l). most fragments are less than 1 cm long, but the pinnules are usually recognizable with a sphenopterid shape and sparse venation. this species is relatively common in the janików locality in layers b, c, d and e. remarks: this species is classified as dicksoniites cf. pluke­ netii due to its fragmentary preservation. 4.6. order trigonocarpales, (medullosaleans) family trigonocarpaceae 4.6.1. genus trigonocarpus brongniart 4.6.1.1. trigonocarpus sp. (pl. 2, fig. b) description: the only representative of the trigonocarpales (medullosales) from the janików locality is this seed trigonocarpus. it is relatively large, 14.5 mm long and 10.5 mm wide, and typical of trigonocarpus with three longitudinal ribs. remarks: barthel (2009) described several 10–25 mm long seeds as trigonocarpus sp. barthel (2009) compared them with trigonocarpus noeggerathii (sternberg) brongniart; however, he did not use this name because of the diverse seed assemblage. trigonocarpus noeggerathii has been figured, by potonié (1893, pl. 33, figs 7, 8) from the permian of the thüringian forest, but the species name has probably been used for various biological species. 4.7. order peltaspermales taylor family autuniaceae doweld 4.7.1. genus autunia krasser 4.7.1.1. autunia conferta (sternberg) kerp (pl. 1, fig. m.) 1864/1865 callipteris affinis göppert: göppert, p. 104, pl. 13, figs. 1 and 2. 1980 callipteris conferta (sternberg) brongniart: barthel et haubold, p. 49–105, figs. 1–11, pls. 1–15 1988 autunia conferta (sternberg) kerp, p. 258–305, pl. 1–25, figs. 3–8. description: only one pinnule fragment from layer c at the janików locality has been found. this has a linguaeform pinnule shape, with a nearly rounded apex and lobate margin, 12 mm long and about 5 mm wide. a vein that divides several times enters each lobe from the midrib (pl. 1, fig. m). remarks: barthel and haubold (1980) studied specimens of autunia conferta in detail and distinguished many forms, including that described earlier by göppert as callip­ teris affinis (göppert, 1864/1865, pl. 13, figs. 1 and 2) from otovice (ottendorf) from the intrasudetic basin. barthel et haubold (1980) named this form as “callipteris conferta ssp. 6 b1” 4.8. class pinopsida burnett order. cordaitanthales meyen (cordaitales scott) family cordaitanthaceae meyen (cordaitaceae grand’eury) 4.8.1. genus: cordaites unger 4.8.1.1. cordaites sp. (pl. 2, fig. 1) description: only three cordaites fragments have been identified in the janików locality (see tab. 1). the biggest fragment is 170 mm long and 19 mm wide with nearly parallel margins. the sample from layer a is 32 mm long and 10 mm wide. apex and bases are not preserved, and the venation itself is insufficient to determine cordaites species. the bigger fragment has about 20 veins; the smaller fragment from layer a (pl. 2, fig. 1) has approximately 25 veins per cm. remark: cordaitaleans from the otovice localities have been recently studied (šimůnek, 2019). also, lipps (1927) described cordaites principalis (germar) geinitz from the permian of unisław śląski from the intrasudetic basin and mentioned 18–24 veins per cm and 3–4 sclerenchymatous bundles between each pair of veins. these characteristics correspond to figure 4. an image of the janików section. hammer is in the fossiliferous layer. g eologia c roatica šimůnek and ploch: new flora from the permian of the intrasudetic basin, poland 205 the type of cordaites principalis (germar) geinitz (see šimůnek, 2015) however, the absence of the leaf apex and base make it problematic to identify to species level. šimůnek (2019) classified cordaitalean species from the permian of the intrasudetic basin based on more complete specimens and assigned similar narrow leaves as cordaites cf. roesslerianus geinitz. according to venation, the janików specimen could belong to either cordaites principalis or c. cf. roesslerianus. 4.8.2. genus cardiocarpus brongniart 4.8.2.1. cardiocarpus sp. (pl. 2, fig. c) description: this seed comes from layer c of the janików locality. it is oval, slightly ovoid, 11 mm long, and 9 mm wide. the sclerotesta represents most of the seed body, sarcotesta being restricted to a narrow rim around the seed. a shallow, narrow groove runs from micropyle to chalaza. remarks: barthel (2009) classified the permian cardio­ carpus seeds as cardiocarpus gutbieri geinitz with reference to potonié (1893). potonié (1893) figured several seeds (his pl. 31, figs 15–19) as cardiocarpus gutbieri, however, these seeds are bigger than those from janików – 15–30 mm long. lipps (1927) also mentioned cardiocarpus gutbieri from unisław śląski, however, he did not mention their dimensions. göppert (1864/1865) mentioned several seed species from the surroundings of broumov and nowa ruda; they require revision. 4.9. plant axes description: these are the most abundant specimens from the janików locality. they are up to 20 cm or more long, less than 1 cm to several cm wide. one, ca. 10 mm wide axis is distorted. these axes may be parts of rachises from creeping ferns or pteridosperms (alloiopteris, nemejcopteris, senftenbergia or dick­ soniites). 5. discussion near janików, the ruprechtice limestone is developed as a calcareous bituminous shale and yields a distinctive macroflora lacking conifers and only rare autunia conferta. however, this assemblage is dominated by creeping and lianascent ferns including nemejcopteris feminaeformis and tree ferns mentioned here lobatopteris sp. nov. table 2. shows that many species are new for the permian of the intrasudetic basin: alloiopteris aff. erosa, nemejcopteris feminaeformis and cyathocarpus cf. densifolius. alloiopteris aff. erosa is probably the youngest example of this genus known anywhere in the world. nemejcopteris feminae­ formis is known from the same age strata from germany (barthel, 2009, 2016) and in the boskovice basin in moravia (šimůnek & martínek, 2009). cyathocarpus cf. densifo­ lius is also known from the same age strata in germany. němejc (1940) described asterotheca thuringiaca from the broumov region, and according to barthel (2009), it is conspecific with lobatopteris geinitzii. senftenbergia was not previously mentioned from the permian of the intrasudetic basin, but a specimen similar to senftenbergia saxonica is deposited in the national museum in prague. dicksoniites plukenetii has not previously been mentioned from the bohemian part of the intrasudetic basin but is recorded by lipps (1927) from polish unisław śląski (langwaltersdorf) in the same strata about 20 km nnw from janików. so, nearly half of the assemblage is not typical for the olivětín member. the flora as a whole suggests a subhumid climate with representatives of different groups of ferns and pteridosperms. the janików plant assemblage is poor and fragmentary, with slightly over 50 specimens having been found within the space of a week. the flora is restricted to a 0.6 m thick calcareous bituminous mudstone (shale) (table 1). this layer was divided into 5 sub-layers from top to base: a, b, c, d, e. only a fragment cor­ daites sp. has been found in sub-layer a. the other layers yielded more plant fragments; however, with so few specimens having been found, it is difficult to trace any clear trend in the distribution of the taxa. only lobatopteris sp. nov. and dicksoniites cf. plukenetii are known from all sub-layers b–e. nearly half of the samples have been found from rocks without knowing the exact location stratigraphically. together with plant fossils, fish remains have also been found. the black shales are considered to represent deep-water deposits. the small fragments (mostly less than 3 cm) indicate longdistance transport from the lakeshore, maybe several hundred table 2. distribution of plant species in individual sub-layers in the janików locality from the top to the base. the last column shows species where the exact position is unknown. species janików total a b c d e cyathocarpus cf. densifolius 1 1 1 3 lobatopteris cf. geinitzii 1 1 lobatopteris sp. nov. 2 2 1 2 2 9 sphenopteris sp. 1 3 4 alloiopteris aff. erosa 3 1 4 nemejcopteris feminaeformis 1 1 5 7 senftenbergia sp. 1 1 2 dicksoniites cf. plukenetii 1 1 1 3 3 9 trigonocarpus sp. 1 1 autunia conferta 1 1 cordaites sp. 1 1 1 3 cardiocarpus sp. 1 1 2 seed 1 1 plant axis 1 1 4 6 total 1 8 10 3 7 24 53 figure 5. a – venation diagram of lobatopteris cf. geinitzii; b – venation diagram of alloiopteris cf. erosa. the shaded pinnule margins represent the gibbous ( distorted) pinnule blade. scale bar = 5 mm. g eo lo gi a c ro at ic a geologia croatica 75/2206 bors, m. (1988): litofaciální a biofaciální analýza svrchních olivětínských vrstev na broumovsku (lithofacial and biofacial analysis of the upper olivětín member in the broumov area).– ms. thesis, faculty of science, charles university, 67 p. 8 pl. prague. (in czech). bossowski, a. (1995): lower silesian coal basin.– in: zdanowski, a. & żakowa, h. (eds.): the carboniferous system in poland.– prace panstwowego instytuta geologicznego, 148, 173–175. cleal, c. j. (2015): the generic taxonomy of pennsylvanian age marattialean fern frond adpressions.– palaeontographica b, 292, 1–3, 1–21. doi: 10.1127/ palb/292/2015/1 cleal, c. j. & thomas, b. a. (1995): palaeozoic palaeobotany of great britain. -chapman & hall, 295 p. london. galtier, j. (2004): a new zygopterid fern from the early carboniferous of france and a reconsideration of the corynepteris – alloiopteris ferns.– review of palaeobotany and palynology, 128, 195–217. doi: 10.1016/s0034-6667(03)00133-7 göppert, h. r. (1864–1865): die fossile flora der permischen formation.– palaeontographica, 12, 1–316. cassel. jerzykiewicz, j. (1987): latest carboniferous (stephanian) and early permian (autunian) palynological assemblages from the intrasudetic basin, southwestern poland.– palynology, 11, 117–131. doi: 10.1080/01916122.1987.9989324 kerp, j. h. f. (1988): aspects of permian palaeobotany and palynology. x. the west and central european species of the genus autunia krasser emend. kerp (peltaspermaceae) and the form-genus rhachiphyllum kerp (callipterid foliage).– review of palaeobotany and palynology, 54, 249–360. doi: 10.1016/00346667(88)90017-6 knight, j. (1983). the stratigraphy of the stephanian rocks of the sabero coalfield, leon (nw. spain) and an investigation of the fossil flora.– palaeontographica b, 187, 155–248. lipps, t. (1927): zur rotliegendflora von langwalterdorf (niederschlesien).– jahrbuch der preußischen geologischen landesanstalt, 1927, 567–592. mosbrugger, v. (1983): organische zusammengehörigkeit zweier fossil-taxa als taxonomisches problem am beispiel der jungpaläozoischen fruktifikationen sco­ lecopteris und acitheca.– review of palaeobotany and palynology, 40, 191–206. mosbrugger, v. (1986): zur klassifikation der pecopteriden: ein vergleich traditioneller gliederungen mit der ergebnisen einer clusteranalyse.– palaeontographica b, 198, 75–99. němejc, f. (1940): the pecopterids of the coal districts of bohemia.– sbornik národniho musea v praze (acta musei nationalis pragae), b ii/1, 1–28. němejc, f. (1948): dodatky k poznání pecopteris oreopteridia schl. et auct. a p. cyathea schl. et auct. [additional notes on pecopteris oreopteridia schl. et auct. a p. cyathea schl. et auct.].– sborník národního muzea v praze, 4, 1, 1–8. němejc, f. (1953): úvod do floristické stratigrafie kamenouhelných oblastí čsr [introduction to the floral stratigraphy of the bituminous-coal districts of the csr].– nakl. čsav, 176 p. prague. němejc, f. (1958): biostratigraphical studies in the carboniferous of the bohemian part of the intrasudetic basin.– rozpravy československé akademie věd, řada matematických a přírodních věd, 68/6, 1–67. opluštil, s., schmitz, m., kachlík, v. & štamberg, s. (2016): re-assessment of litostratigraphy, biostratigraphy, and volcanic activity of the late paleozoic intra-sudetic, krkonoše-piedmont and mnichovo hradiště basins (czech republic) based on new u-pb ca-id-tims ages.– bulletin of geosciences, 91/2, 399–432. potonié, h. (1893): über das rothliegende des thüringer waldes. teil ii: die flora des rothliegenden von thüringen.– abhandlungen der preußischen geologischen landesanstalt, neue folge, 9, 1–298, berlin. rieger, z. (1966): fytopaleontologický výzkum broumovského permu (palaeobotanical research of the broumov permian).– in: tásler, r. et al. (eds): základní geologický výzkum broumovského permu.– ms. geofond, 33 p., praha. (in czech). schlotheim, e. f. von (1820): die petrefactenkunde auf ihren jetzigen standpunctedurch die beschreibung seiner sammlung versteinerter und fossiler überreste des thier und pflanzenreichs der vorwelt erläutert. 435 p., beckersche buchhandlung gotha. šimůnek, z. (2015): cuticles of the polish type material of cordaites palmaeformis (göppert) weiss and a cordaites principalis-like form from germany, pennsylvanian.– review of palaeobotany and palynology, 223, 50–70. doi: 10.1016/j.revpalbo.2015.09.001 šimůnek, z. (2019): revision of the genus cordaites unger from the permian of the intrasudetic basin (broumov formation, olivětín member czech republic).– geologia croatica, 72, 3, 163–172. doi: 10.4154/gc.2019.16 šimůnek, z., drábková, j. & zajíc, j. (1990). paleontologické zpracování sběrů z lokality vrchlabí – zářez silnice na jz. okraji města. ms report (palaeontological evaluation of the collection from the vrchlabí locality – road cut in the sw edge of the city).– archiv of the czech geological survey, prague, 83 p. 52 pls. praha. (in czech) metres or more. the presence of fish and coprolites and an absence of mud cracks and ripples indicate relatively deep-water conditions from the beginning of sedimentation. the plant remains include tiny fragments of pinnules and pinnae, mostly of arborescent and creeping ferns and pteridosperms, probably from coastal vegetation. the seed plants probably grew behind this barrier of coastal vegetation, but their existence is only indicated by cardiocarpus and trigonocarpus seeds. during the sedimentation of the lake deposits, the climate was probably subhumid (bashforth et al., 2021). 6. conclusion the hygrophilous to mesophilous plant assemblage from the janików locality comprises arborescent and lianascent ferns and pteridosperms probably representing coastal vegetation of the ruprechtice lake. the climate in this interval of the asselian was subhumid. cyathocarpus cf. densifolius is a new species record for the intrasudetic basin. nemejcopteris feminaeformis and al­ loiopteris aff. erosa have their last appearance data here. the remains of the fossil-genera sphenopteris, lobatopteris and senf­ tenbergia could not be classified to species. pteridosperms were represented by dicksoniites cf. plukenetii and autunia conferta. a seed trigonocarpus sp. indicates medullosan pteridosperms growing behind the barrier of coastal vegetation. cordaitaleans were presented by cordaites sp. and cardiocarpus sp. although arid climates tended to prevail in this region during the asselian, the assemblage reported here shows that there could also be intervals with subhumid climates. acknowledgements this work was subsidised by the grant 2017/26/m/st10/00646 (polish national science centre) and the strategic research plan of the czech geological survey (dtrvo/čgs 2018/2022). the authors thank to dr. r. rössler and an anonymous reviewer for their valuable remarks. references barthel, m, (1968): „pecopteris“ feminaeformis (schlotheim) sterzel und „araucarites“spiciformis andrae in germar. – coenopterideen des stephans und unteren perms.– paläont. abh., b, 2/4, 727–742. barthel, m. (1976): die rotliegendflora sachsens.– abhandlungen des staatlichen museums für mineralogie und geologie dresden, 24, 1–90. barthel, m. (1980a): pecopteris­arten e. f. von schlotheims aus typuslokalitäten in der ddr.– schriftenr. geol. wiss. berlin, 16, 275–304. barthel, m. (1980b): pecopteris (scolecopteris)­arten aus dem rotliegenden von manebach in thüringen. wissenschaftliche zeitschrift der humbotdt-universität zu berlin, math.-nat. r., 29/3. barthel, m. (2009): die rotliegendflora des thüringer waldes.– veröffentlichungen naturhistorisches museum schleusingen, sonderveröffentlichung 2009 (press of the chapters from years 2003–2008). barthel, m. (2016): die rotliegendflora der döhlen-formation [the lower permian (rotliegend) flora of the döhlen formation].– geologica saxonica, 61/2, 106–238. barthel, m. & haubold, h. (1980): zur gattung callipteris brongniart. teil i: die ausbildung von callipteris conferta (sternberg) brongniart im mitteleuropäischen rotliegenden.– schriftenreihe für geologische wissenschaften, 16, 49–105, berlin. bashforth, a. r., dimichele, w. a., eble, c. f., falcon-lang, h. j., looy, c. v. & lucas, s. g. (2021): the environmental implications of upper paleozoic plant-fossil assemblages with mixtures of wetland and drought-tolerant taxa in tropical pangea.– geobios, 68, 1–45. doi: 101016/j.geobios.2021.04.002 bek, j. & opluštil, s. (2021): early pennsylvanian and early permian (bashkirian–asselian) miospore and pollenassemblages of the czech part of the intra-suderic basin.– bulletin of geosciences, 96/3, 341–379. boersma, m. (1978). a survey of the fossil flora of the ‚illinger flözzone‘ (‚heusweiler schichten‘, lower stephanian, saar, german federal republic).– review of palaeobotany and palynology, 26, 41–92. doi: 10.1016/0034-6667(78)90006-4 g eologia c roatica šimůnek and ploch: new flora from the permian of the intrasudetic basin, poland 207 šimůnek, z. & martínek, k. (2009): a study of late carboniferous and early permian plant assemblages from the boskovice basin, czech republic.– review of palaeobotany and palynology, 155, 275–307. doi: 10.1016/j.revpalbo.2008.05.006 sternberg, k.m. von (1825): versuch einer geognostisch botanischen darstellung der flora der vorwelt vol. 1(4): 1–48 pp. tent. i–xlii, ernst brenck’s wittwe, regensburg. tásler, r. et al. (1966): základní geologický výzkum broumovského permu. (principal geological research of the broumov permian).– ms geofond, praha. (in czech). tásler, r., čadková, z., dvořák, j., fediuk, f., chaloupský, j., jetel, j., kaiserová-kalibová, m., prouza, v., schovánkováhrdličková, d., středa, j., střída, m. & šetlík, j. (1979): geology of the bohemian part of the intra-sudetic basin. 296 p. academia, praha. [in czech with english summary] wagner, r. h. (1983): a lower rotliegend flora from ayrshire.– scottish journal of geology, 19/2, 135–155. wagner, r.h. & álvarez-vázquez, c. (2010): the carboniferous floras of the iberian peninsula: a synthesis with geological connotations.– review of palaeobotany and palynology, 162, 239–324. doi: 10.1016/j.revpalbo.2010.06.005 zeiller, r. (1890): bassin houiller et permien d’autun et d’épinac.– études des gites minéraux de la france, texte 1–304 p., atlas 89 pls. paris. zobel, o. & carnall, r. (1831–1833): geognostische beschreibung von einem theile des niederschlesisch-glätzischund böhmischen gebirges.– archiv min. (karsten), bd. 3 (1831): 3–95, 277–361; bd. 4 (1832): 3–173. g eo lo gi a c ro at ic a geologia croatica 75/2208 plate 1 flora from the janików, božanovský creek, locality. b, c, d and e designate the sub-layer from which the specimen originated; (-) means the sub-layer is unknown. specimens from the collections of the czech geological survey, prague. all figures scale bar = 5 mm. a – alloiopteris cf. erosa, b, inv. no.: zš 856., b and c – nemejcopteris feminaeformis, b and (-), inv. nos. zš 857 and zš 858. d and e – senftenbergia sp., c – (-), inv. nos. zš 859 and zš 860., f and g – lobatopteris sp. nov., c – b, inv. nos. zš 861 and zš 862., h – lobatopteris cf. geinitzii, c, inv. no.: zš 863, i – k – cyathocarpus cf. densifolius, c–(-)–e, inv. nos. zš 864, zš 865 and zš 866., l – dicksoniites cf. plukenetii, d, inv. no.: zš 867., m – autunia cf. conferta, c, inv. no.: zš 868. g eologia c roatica šimůnek and ploch: new flora from the permian of the intrasudetic basin, poland 209 plate 2 flora from the janików, božanovský creek, locality a and c designate the sub-layer from which specimen originated; (-) means the sub-layer is unknown. specimens from the collections of the czech geological survey, prague. all figures scale bar = 5 mm. a – cordaites sp., a, inv. no.: zš 868., b – trigonocarpus sp., (-), inv. no.: zš 870., c – cardiocarpus sp., c, inv. no.: zš 871. www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2025 | 78/1 | 61–86 | 16 figs. | 2 tabs. | 1. introduction the neogene adana basin, located in southern turkey, holds significant geological importance due to its proximity to the triple junction of the arabian, african, and anatolian plates. it is believed that the basin developed as a result of extensional tectonics caused by the southward rollback of the african plate, as proposed by robertson (1998). over the years, numerous general geological-stratigraphic studies have been conducted in the region by researchers such as schmidt (1961), yeti̇ş & demi̇rkol (1986), yeti̇ş et al. (1986), ünlügenç & demirkol (1988) and ünlügenç (1986, 1993). detailed discussions on the general stratigraphy and geology of the adana basin were presented by yeti̇ş (1988) and ünlügenç (1993), revealing its main sedimentary and tectonic characteristics. more recently, nurlu et al. (2021) reported 87sr/86sr analysis for carbonatic tuffites in the kuzgun for ma tion, providing ages between 20 and 27 ma, cor responding to the burdigalian–chattian period. they suggested that these tuffites were originally deposited during the middle–upper miocene and were later transported from a northerly source area. the basis of sr isotope stratigraphy lies in the assumption that the 87sr/86sr of seawater is relatively constant throughout the earth’s oceans, with residence times of sr in seawater ranging from approximately 2.5 to 5 million years (broeker & peng, 1982; mcarthur, 1994) or even less (kuznetsov strontium isotopic stratigraphy of the miocene adana basin (s. anatolia) and its geological implications ahmet can akinci1,* 1 çukurova university, faculty of engineering, department of geological engineering, adana, turkey; (*corresponding author: acakinci@cu.edu.tr) doi: 10.4154/gc.2025.05 abstract this paper presents the first 87sr/86sr data and its geological implications for the entire stratigraphic sequence of the neogene adana basin, one of the largest basins in southern turkey (eastern mediterranean). the adana basin is strategically located near the convergence point of the african, arabian, and anatolian plates, making it vital for understanding the regional geological history. in this study, 15 systematically collected samples from six different formations within the adana basin were subjected to strontium isotope analysis (87sr/86sr). the results were presented and interpreted for all units except the handere formation (messinian fluvial, shallow marine-lagoon deposits). notably, some of the corresponding ages of the recorded 87sr/86sr results have contradicted the published biostratigraphic ages from the literature. to explain the observed deviations in the güvenç and kuzgun formations, geochemical, petrographic, and sem analyses were conducted, revealing that these deviations are generally related to diagenetic alteration and the high detrital content of the units. additionally, fundamental palaeontological studies were carried out to provide supporting information. the 87sr/86sr deviations observed in the shallow marine units can be attributed to multiple factors, including short-term sea-level fluctuations, continental run-off, terrestrial feeding/riverine input, and volcanic activity during the late tortonian–messinian period. new field observations combined with 87sr/86sr data enabled the differentiation of distinct reef carbonates with similar lithologies. these findings demonstrate the formation of various reef levels through multiple short-term phases alongside a gradual regression of sea level in the basin during the late miocene period. et al., 2012), which is significantly greater than the mixing time of the ocean (approximately 103 years). the study of sr-isotope (87sr/86sr) variations in cenozoic seawater was first described by burke et al. (1982) and further improved by koepnick et al. (1985, 1988) and elderfield (1986). since then, the neogene sr-isotope seawater curve has received considerable attention and has been investigated by various researchers (hodell & woodruff, 1994; oslick et al., 1994). these advancements have led to the establishment of a detailed marine sr-isotope chronology for neogene basins, based on high precision measurements. consequently, stratigraphic studies, primarily reliant on palaeontology and relative dating, can now be supported by a chemical quantitative method based on the sr isotope composition of sediments. this chemical approach has opened new avenues for understanding the geochronological development of basins. however, it is important to consider factors such as chemical weathering, soil formation, and seasonal alterations that can affect the sr isotopic com posi tion in deposits (cai et al., 2020). the dissolution of minerals including biotite, feldspar, and plagioclase under different inten sities of chemical weathering can lead to variable 87sr/86sr contents in water and sediment (yang et al., 2007). despite these challenges, unexpected deviations in 87sr/86sr ratios re main crucial indicators for assessing diagenetic processes in rock units, salinity reconstructions, sediment sources, and palaeo environmental evaluations (veizer, 1983; mcarthur et article history: manuscript received: april 25, 2024 revised manuscript accepted: december 05, 2024 available online: february 27, 2025 keywords: adana basin, 87sr/86sr, stratigraphy, neogene mailto:acakinci@cu.edu.tr g eo lo gi a c ro at ic a 62 geologia croatica 78/1 al., 2001; yang et al., 2007; wierzbowski, 2013; schildgen et al., 2014). this paper aims to present the first strontium isotopic composition (87sr/86sr) and its geological implications for the deposits from the adana basin. the available age deter minations were primarily based on micro-palaeontological studies with limited single-unit (even member) isotopic determinations. strontium isotope stratigraphy of basin sediments, besides determining the age of the sample in question, allows facies correlations and provides more detailed data about the basin’s evolution. in this study, the obtained 87sr/86sr compositions of the units outcropping in the adana basin are compared with the literature and are interpreted to provide a foundation for further research. in addition, data pertaining to late miocene reefal sedimentation in the basin and probable episodic relative sea-level changes during the tortonian–messinian period (ilgar et al., 2013), resulting in transgressive sedimentation, are discussed. 2. geological setting and stratigraphy the adana basin was developed on the palaeozoic and mesozoic basement units that form a south-verging imbricate thrust stack in the south of the taurus mountain belt in southern anatolia (burton-ferguson et al., 2005). the adana basin is separated from the i̇skenderun basin by the ne-sw trending misis mountain range in the south. the basin hosts a nearly 6000 m thick sedimentary succession, spanning rock units from the miocene to the recent (burtonferguson et al., 2005). according to the latest geodynamic models, the adana basin lies above the zone of cenozoic suturing between the afro-arabian and eurasian plates (dewey & şengör, 1979; şengör & yilmaz, 1981; robertson & dixon, 1984; gealey, 1988; kahle et al., 2000; reilinger et al., 2010; mahmoud et al., 2013). the timing of the collision between the arabian and anatolian plates has been debated. some suggest it occurred during the late cenozoic (kelling et al., 1987) or middle miocene (şengör, 1979; şengör & yilmaz, 1981; dewey et al., 1986). more recent studies propose an eocene– miocene age (hempton, 1985; yilmaz, 1993). this extension stretches from the mediterranean sea to kyrenia. following the continental collision, the continued northward movement of the arabian plate along the southeastern anatolian orogenic belt resulted in intense compressional deformation, thickening the eastern anatolian crust. further shortening in the region led to the formation of two major fault zones namely the north anatolian fault zone (nafz) and the east anatolian fault zone (eafz) (albora et al., 2006; barka & kadinsky-cade, 1988; peri̇nçek & çemen, 1990). within this tectonic framework, the neogene sequence of the adana basin fill is represented by seven formations (figs. 1, 2) representing different facies characteristics, and developed just south of the eastern taurus mountain range. it has been reported that these formations were deposited due to extensive subsidence in the basin during the early and middle miocene (ünlügenç & akinci, 2020). this thick sedimentary sequence can be divided into pre-transgressive, transgressive, and regressive sequences. the pre-transgressive gildirli formation was deposited during the late oligocene–early miocene and is exposed on the northern flank of the basin (ünlügenç, 1993; ünlügenç & akinci, 2020). during the early miocene, the adana basin experienced rapid subsidence driven by extensional tectonics, leading to marine incursions and gradual sedimentary infilling. this was followed by a significant northward marine transgression during the langhian–serravallian, resulting in a thick sedimentary accumulation. by the tortonian–messinian, subsidence decreased, indicating a shift in sediment transport regimes due to tectonic uplift and sea-level changes. late miocene to pliocene compressional events further reshaped the basin, influenced by sinistral fault movements that defined its current structure (ünlügenç, 1986, 1993; ünlügenç & demi̇rkol, 1988; ünlügenç & akinci, 2020; akinci & ünlügenç, 2021; akinci et al., 2023). a possible marine inundation from the south during the early miocene led to the deposition of a transgressive sequence, including the kaplankaya, karaisalı, cingöz, and güvenç formations which make up most of the adana basin fill (ünlügenç, 1993; ünlügenç & akinci, 2020). while the kaplankaya and karaisalı formations characterise the main miocene shallow-marine/platform deposits in the adana basin, the turbiditic cingöz formation represents sedimentation in the deeper parts of the basin (özçeli̇k & yeti̇ş, 1994). the kaplankaya formation includes a wide range of facies deposited in the shallow parts of the basin along with the reefal karaisalı formation. the güvenç formation, which is generally dominated by lithologies including shale and mudstone, covers the fore reef, deep sea, and shallow sea facies stratigraphically from bottom to top (özçeli̇k & yeti̇ş, 1994). the kuzgun formation, which overlies the güvenç formation with a low-angle unconformity, began with levels consisting of coastal, beach, and meandering river sediments, indicating the early stages of the regressive period in the basin (ünlügenç et al., 2019). ilgar et al. (2013), suggesting that a short-lived relative sea level rise that led the shallowmarine sedimentation in the early tortonian was accompanied by a second generation of reefal limestones along the basin margin (fig. 2). the messinian-pliocene handere formation consists of sandstone, siltstone, and terrestrial sediments including marl and gypsum. it overlies the kuzgun formation with a low-angle unconformity and is, in turn, unconformably overlain by quaternary terrace-caliche and alluvium deposits (ünlügenç, 1993; sinaci, 2010; şafak et al., 2021). 2.1. the gildirli formation the gildirli formation is a pre-transgressive continental conglomeratic unit, underlying the miocene sediments of the adana basin (ünlügenç, 1993; derman & gürbüz, 2007). this formation crops out around the akdam, gildirli, and karakılıç villages and is dominated by alternations of conglomerate, sandstone, shale, and mudstone. the unit is observed to fills the irregular pre-miocene topography formed by mesozoic and palaeozoic rock units. conglomerates and other clastic sediments within the unit are generally alluvial in character and present a distinct reddish colour. the reddishbrown, thick to very thick-bedded conglomerates display g eologia c roatica 63akinci et al.: strontium isotopic stratigraphy of the miocene adana basin (s. anatolia) and its geological implications cross-bedding and include well rounded, poorly sorted pebbles which are derived from palaeozoic–mesozoic carbonates and ophiolites. the gildirli formation unconformably overlies the oligocene lacustrine deposits of the karsantı formation in the çokak area and is transitionally overlain by the kaplankaya and karaisalı formations. figure 1. geological map of the study area (modified after ünlügenç, 1993). sampling/sedimentary log locations for strontium analyses are indicated on the map. g eo lo gi a c ro at ic a 64 geologia croatica 78/1 2.2. the kaplankaya and karaisalı formations these two closely related units together represent the miocene shallow-marine/platform deposits in the basin (ünlügenç & akinci, 2020). the kaplankaya formation includes alternations of conglomerates, sandstones, mudstones, shales, and marls. the unit is exposed in the northern part of the adana basin around the arapali, gülüşlü, taşobası, çokak, koçmarlı, and hankaşı villages (fig. 1). the kaplankaya formation was deposited in a shallow marine environment close to the shore, surrounding the reefal karaisalı limestone. it transitions into the turbiditic cingöz formation in the deeper parts of the basin in the east/northeast of the karaisalı district and passes into the deeper marine güvenç formation in the south (fig. 2). the kaplankaya formation unconformably overlies the gildirli formation, mesozoic–palaeozoic basement rocks, and the oligocene karsantı formation. the sedimentary environments represented in this unit include an alluvial fan type setting at the lower levels, passing upward figure 2. stratigraphic column showing the relationships of the units in the adana basin (modified after ilgar et al., 2013 and ünlügenç, 1993) g eologia c roatica 65akinci et al.: strontium isotopic stratigraphy of the miocene adana basin (s. anatolia) and its geological implications into a fan delta and shallow marine environment. the fossil evidence indicates that the kaplankaya formation was deposited during lower–middle miocene time (ünlügenç, 1993). the karaisalı formation comprises massive and thickbedded reefal carbonates and is exposed along the northern margin of the adana basin, especially around the western part of the karaisalı district. the unit includes corals, coralline algae, molluscs, echinoderms, foraminifera, and minor bryozoans. the carbonate rocks of the unit were deposited on pre-miocene topographical highs and are represented by coral wackestone, packstone, and benthic foraminiferal packstone subfacies that form the talus deposits on the submarine forereef slopes (yalçin & görür, 1984). taraf et al. (2013) identified three facies and nine microfacies pointing to different parts of the reef, especially based on the lithology and fossil content of the unit. the carbonates of the karaisalı formation are seen in the form of both barrier and patch reefs and microfossil determinations have been reported to indicate a burdigalian–langhian time interval of deposition (ünlügenç, 1993). according to ilgar et al. (2013), the cingöz and güvenç formations are laterally transitional and conformably overlie the kaplankaya fm (fig. 2). the karaisalı and closely associated (interfingering) clastic kaplankaya formations rest directly on the palaeozoic units and the gildirli formation with an angular unconformity. in the nw of the karaisalı district, the kaplankaya formation unconformably overlain by a thin layer of reef carbonates. 2.3. the cingöz formation the cingöz formation is a turbiditic submarine-fan unit that crops out widely in the northern part of the adana basin, around the cingöz, kuşçusofulu, eğlence, nergizlik, and eğner villages. the unit forms two large submarine fans in the east of the karaisalı district, a major one to the east and a smaller one to the west. the cingöz formation comprises alternations of sandstones, pebbly sandstones, shales, mudstones, and marls. the sandstones exhibit both lenticular and parallel bedding, erosional bases and include slumps and abundant sole marks. additionally, the sandstones show a partial “bouma sequence”. pebbly sandstones and occasional conglomerates are observed to have been deposited as submarine channel fills. the grain size of the clastics in the unit decreases towards the south indicating a southward transport. the cingöz formation rests on the gildirli and kaplankaya formations with a locally erosive contact (ünlügenç & şafak, 1992). the western submarine fan system of the cingöz formation has been supplied through a major channel formed by a palaeo-valley (derman & gürbüz, 2007). according to their fossil determinations, nazi̇k & gürbüz (1992) documented that the cingöz formation was deposited during the late burdigalian–serravallian interval. 2.4. the güvenç formation the güvenç formation is characterized by the alternations of shales, mudstones, siltstones, marls, and fine-grained sandstones. the fine-grained clastic rocks of the unit are bluish to greenish-grey in colour, thinly parallel bedded, with convolute lamination. they are also carbonaceous and include abundant microfauna. the güvenç formation is exposed mainly in the eastern and south-eastern parts of the karaisalı district, around the güvenç, sevinçli, and çatalan villages (fig. 1). şafak & ünlügenç (1992) reported that the kaplankaya formation conformably overlies the gildirli formation and grades vertically and laterally into the karaisalı formation limestones (fig. 2). defining the boundary between the cingöz and güvenç formations is challenging due to the gradual deepening of the depositional environment (ünlügenç, 1993). the güvenç formation represents a shoaling upward sequence toward the south and passes upward into the kuzgun formation with a low degree angular discordance that characterises the beginning of the regressive cycle in the basin. 2.5. late miocene carbonates late miocene reefal carbonate deposits were described by atabey et al. (2000) as the tırtar formation in the adjacent westerly mut basin. the units are generally considered to be the slightly younger (late miocene) counterparts of the earlymiddle miocene karaisalı and kaplankaya formations (early– middle miocene) in the adana basin. in the central taurus miocene basins adjacent to the adana basin, the late miocene aged tırtar and ballı formations unconformably overlie the middle miocene sediments (atabey et al., 2000). these younger carbonates consist of reefal limestones similar to the underlying karaisalı formation. the ballı formation, like the kaplankaya formation in the adana basin, consists of finegrained clastics, marl and other semi-pelagic and pelagic sediments deposited around and beyond the reef and platform carbonates (atabey et al., 2000). these units were first presented in the stratigraphy of the adana basin by ilgar et al. (2013) but was not mapped in detail (fig. 2). the authors suggest that the transgression (relative sea-level rise) initiated a second generation of reef formation with shallow-marine sedimentation along the basin margin in the early tortonian, the late miocene reef carbonates, deposited on the older reefal limestones of the karaisalı formation. similar young reefal carbonate formations occur as patches in the southern parts of adana city centre, around the neighbourhoods of köklüce and alihocalı, where they are being exploited as limestone quarries for construction and cement production. 2.6. the kuzgun formation fine-grained clastic sediments of the güvenç formation are unconformably overlain by coarser-grained deposits of the kuzgun formation. although, the boundary is discordant, the exact duration of the hiatus is not well defined. the kuzgun formation mainly outcrops around the kuzgun, salbaş, karakuyu, and kaşoba villages (nw adana). three facies types were differentiated in the unit (ünlügenç, 1993). at the base, the formation begins with channelized conglomerates, followed by cross-bedded sandy conglomerates, sandstones, and mudstones rich in oysters and shells, which are referred to as the kuzgun member. this member represents the characteristics of meandering river and beach deposits and passes upwards into flood plain facies (ünlügenç, 1993). a tuffite-dominated volcanoclastic-marl-shale alternating sequence located at the top of this member is known as the salbaş tuffite member. in their study on these tuffites, şafak et al. (2021) determined that based on the biostratigraphic g eo lo gi a c ro at ic a 66 geologia croatica 78/1 findings, the environment was lagoonal, transitioning to shallower marine conditions with a deepening trend upwards. located at the top of the formation, the memişli member rests stratigraphically on the salbaş tuffite member and consists of thickening and coarsening upward sandy-silty sequences characterising deltaic facies. the kuzgun formation transitionally passes upward into the handere formation. 2.7. the handere formation the youngest neogene unit of the adana basin, the handere formation, transitionally overlies the memişli member of the kuzgun formation in the southernmost part of the basin. the unit crops out along an approximately east-west trend in the northern parts of the adana city centre and is discordantly overlain by quaternary terrace-caliche deposits. the handere formation consists of sandstones, mudstones, marls, and conglomerates of f luvial, shallow marine, and lagoonal character (ünlügenç, 1993). although cross-bedded and channelised conglomeratic deposits, (mainly located at the base levels) are indicative of a fluvial origin, gürbüz (1985) reported that the conglomeratic sequences exposed in the east of the seyhan dam include some shallow marine intercalations. these sandy and conglomeratic deposits are succeeded by sandy-silty sediments and then pass upwards into thick, fossiliferous carbonaceous mudstone deposits. towards the top of the unit these fine-grained clastics are succeeded by less well cemented sandstones and siltstones including gypsiferous lenses known as the gökkuyu gypsum member (fig. 2). 3. methodology seawater isotope composition is uniform across modern oceans due to the relatively long residence time of strontium (1-5106 years) (mcarthur, 1994; mcarthur et al., 2012; kuznetsov et al., 2012) and the short mixing time of water masses (jones & jenkyns, 2001). therefore, the sr isotope ratio (87sr/86sr) of ancient seawater can be constructed from well-preserved authigenic minerals and used for studying the stratigraphy of marine sediments. the variation in the isotope composition of sr may also be a marker of diagenetic alteration and can be used to evaluate fluid-rock interactions of marine rocks (ullman et al., 2013). the sr contents of seawater vary due to several factors: (a) the amount of high 87sr/86sr terrigenous detritus entering the ocean from continental weathering relative to the low 87sr/86sr contents of oceanic crust due to hydrothermal exchange at mid-ocean ridges; and (b) the seafloor dissolution of carbonates acting as a buffer by adding sr at a similar ratio to seawater (oslick et al., 1994; mcarthur, 1994). the diagenetic carbonate flux is an order of magnitude less than the erosional and hydrothermal fluxes. much effort has been directed at constraining the shape of the sr ratio curve over time (miller et al., 1991; oslick et al., 1994; gleason et al., 2002). thus, the highest temporal resolution is obtained for portions of the seawater curve that exhibit the highest rate of change in the 87sr/86sr ratio as a function of time. there was an acceptable rate of change throughout the late miocene. in the mediterranean region, the sr isotopic methods failed because the basins were constrained and the strontium isotope ratio was affected by a change in the freshwater to seawater ratio, resulting in anomalous 87sr/86sr ratios in the messinian period (flecker & ellam, 2006). strontium is derived from biogenic carbonate, which is the major sink of sr in the oceans (brass, 1976; hodell, 1994). organisms that form carbonate shells do not fractionate sr isotopes. therefore, it is reasonable to assume that the 87sr/86sr ratio in biogenic carbonate reflects the seawater composition at the time of precipitation. for strontium analysis, composite samples of benthic foraminifera, gastropods, marls, and carbonatic clastics were selected from the specific sites of the adana basin (fig. 1). a leaching process was carried out in order to remove the residues related to contamination after the samples were ground into rock powder. this process was performed using diluted hno3 in an ultrasonic bath to eliminate surface contamination and detrital impurities prior to geochemical studies. three repetitive ultrasonic baths with double distilled water were used to clean the gastropod/ostrea tests. strontium isotope analyses (87sr/86sr) were performed at the radiogenic isotope laboratory of middle east technical university, ankara, turkey. chemical treatment and column chemistry were performed in a 100-class clean laboratory with ultrapure chemical agents. powdered rock samples (approximately 120 mg) were leached with 4 ml of 14 n hno3 for 4 days on the hot plate (>100 °c). these samples were dried and dissolved overnight in 4 ml 6 n hcl on the hot plate. afterward, samples were re-dried, then dissolved in 1 ml 2.5 n hcl for sr chromatography. strontium was separated from other elements in 2 ml volume biorad ag50 w-x8 (100–200 mesh) resin in teflon columns in a 2.5 n hcl medium. strontium was loaded on single re filaments with 0.005 n h3po4 and ta activator to improve efficiency. 87sr/86sr ratios are normalized with 86sr/88sr = 0.1194. measurements were made by multicollection using the triton thermal ionization mass spectrometer (thermo-fisher). during the analyses the sr nbs 987 standard was measured as 0.710260 ± 10 (n = 3) and no bias correction was applied on the measured sr isotope data. the analytical uncertainties were determined to be at the 2 sigma level. further details of the isotope methods that followed at the laboratory are described by köksal et al. (2019). since diagenetic alteration could potentially alter the original sr composition in the rocks, thin sections were prepared from the collected hand samples and examined in detail under a polarizing microscope to determine whether they had undergone any alteration. an elementary palaeontological study was carried out to test the 87sr/86sr age data for the cingöz and güvenç formations, which were thought to be affected by diagenetic alteration. for this purpose, some of the collected rock samples of these units crushed and treated with hot water and 15% diluted hydrogen peroxide (h2o2) in glass beakers for at least 24 hours. the disaggregated residues later were subsequently washed through 0.60, 0.120, and 0.230 mm mesh sieves and placed in sample bags after oven drying. the microfossils were separated from grains under the microscope and placed on slides for taxonomic identification. sem photomicrographs of the identified fossils were captured using the fei quanta 650 in the central research laboratory of çukurova university. g eologia c roatica 67akinci et al.: strontium isotopic stratigraphy of the miocene adana basin (s. anatolia) and its geological implications sedimentological logs were prepared from the sr sampling sites to reveal the general sedimentological characteristics of the unit at that level. ca, fe, mg and mn concentrations used in diagenetic alteration assessment were determined in the çukurova university geological engineering department geochemistry laboratory with wet chemical methods and using atomic absorption spectrometer (perkin elmer aanalyst 700). sr concentration measurement was performed in çukurova university’s central laboratory using an aas (perkin elmer pinaacle 900t). 4. assessment of diagenetic alteration diagenesis of sedimentary rocks may lead to decreased concentrations of sr and increased mn and fe (e.g., brand & veizer, 1980; veizer, 1983; al-aasm & veizer, 1986). marine carbonates reflect the strontium isotopic composition of ambient seawater, which allows determination of the time of mineral formation if not affected by advanced diagenesis (howarth & mcarthur, 1997; mcarthur et al., 2001; mcarthur et al., 2012). although the 87sr/86sr compositions are preferably measured on fossil shells such as oysters and pectinids because of their high preservation potential and reliability (scasso et al., 2001; schneider et al., 2009; brandano & policicchio, 2012; vescogni et al., 2014; argentino et al., 2017), sufficient quantities of fossil shells for 87sr/86sr analysis may not be available in all cases (e.g. for units dominated by planktonic species). in addition, it is not possible to extract tests from strongly cemented reef carbonates. nevertheless, we have ensured through widely used petrographic methods such as thin sections and sem images that it has not been subjected to significant diagenetic alterations. in this study, oyster and gastropod fossil shells were used in one of the six units (kuzgun formation) for 87sr/86sr analysis, however, this was not possible for the other units due to insufficient fossilised shell content for comprehensive analysis (tables 1, 2). for this reason, geochemical, petrographic evaluation of thin sections and sem images were used to assess bulk samples, and any effects of diagenetic alteration in potentially altered samples will be considered in subsequent geological evaluations. 4.1. thin-section examination carbonate rocks are exposed to especially meteoric and groundwater during diagenesis and therefore they can show alteration. the investigated carbonate rocks in the adana basin are miocene in age and have been uplifted (between 150600 m) by gradual regression (ünlügenç, 1993; ünlügenç & akinci, 2020) since this period, and it is unlikely that they have undergone metasomatism due to deep burial. in this case, carbonate material could be dissolved by the acidic waters and secondary carbonate or ferrous/silica mineralization can be present along micro-cracks or pores. in addition, secondary dolomitization with magnesium enrichment can also be seen. these alteration features can be determined by petrographic examinations made on thin sections under a polarizing microscope. thus, carbonate rocks that lack abundant secondary crystallisation, dolomitization, or iron enrichment, and have preserved their original fossil and textural characterta bl e 1. g eo ch em ic al a na ly si s r es ul ts (t ra ce e le m en t c on ce nt ra tio ns ) o f t he s tu di ed ro ck s am pl es . u ni t sa m pl e co de sa m pl e ty pe 87 sr /86 sr % c a % m g fe (p pm ) m n (p pm ) sr (p pm ) m g/ ca fe /s r m n/ sr ku zg un f m . kz -1 o st re a sh el l 0. 70 89 67 21 .3 1 1. 55 10 90 17 5 75 1. 9 0. 07 3 1. 45 0. 23 kz -2 o st re a sh el l 0. 70 91 72 33 .8 9 1. 3 68 0 23 49 44 8. 8 0. 03 8 1. 52 5. 23 kz -3 g as tr op od sh el l 0. 70 91 6 35 .8 6 0. 81 38 0 16 20 46 7. 9 0. 02 3 0. 81 3. 46 l. m io ce ne r ee f c ar bo na te s t2 bu lk ro ck – l im es to ne 0. 70 89 62 37 .2 9 1. 18 12 00 11 0. 8 50 8. 9 0. 03 2 2. 36 0. 22 g üv en ç fm . g -1 cl ay ey l im es to ne 0. 70 86 46 9. 48 2. 63 31 30 58 6. 4 27 9 0. 27 7 11 .2 2 2. 10 g -2 ca lc ar eo us d et rit ic 0. 70 82 92 8. 51 3. 32 36 00 65 2. 5 23 1 0. 39 0 15 .5 9 2. 82 g -3 ca lc ar eo us d et rit ic 0. 70 81 49 7. 93 3. 15 38 80 68 5. 2 24 6. 9 0. 39 7 15 .7 1 2. 78 ci ng öz f m . c1 ca lc ar eo us d et rit ic 0. 70 88 48 8. 19 2. 52 33 40 63 3. 7 22 9 0. 30 8 14 .5 9 2. 77 c2 ca lc ar eo us d et rit ic 0. 70 82 5 6. 16 1. 66 35 70 37 8. 3 11 7 0. 26 9 30 .5 2 3. 23 c3 cl ay ey l im es to ne 0. 70 82 36 17 .8 5 3. 75 25 50 36 5. 4 31 5. 4 0. 21 0 8. 08 1. 16 ka pl an ka ya /k ar ai sa lı fm . k2 bu lk ro ck – l im es to ne 0. 70 89 09 29 .6 1. 99 10 40 20 2. 6 84 7. 8 0. 06 7 1. 23 0. 24 k4 bu lk ro ck – l im es to ne 0. 70 89 54 19 .6 4 2. 79 22 30 25 5. 4 48 0 0. 14 2 4. 65 0. 53 g eo lo gi a c ro at ic a 68 geologia croatica 78/1 istics, are considered to have undergone minimal diagenetic alteration. the carbonate rocks compiled for sr isotope analysis from the late miocene carbonates (figs. 3a-c) show a boundstone texture expressing the reefal facies and dominated by algae. the rock also contains small amounts of microfossils and is cemented by sparite. it does not show any significant recrystallization in thin section examination, and it largely preserves its original texture. the samples collected from the kaplankaya fm. contain abundant microfossils (mostly foraminifera) and include a small amount of (5-10%) detrital fragments in a relatively fine-crystalline sparry calcite cement (packstone) (figs. 3d-f). the rock lacks cracks/pores, exhibits no recrystallization, and preserves its original sedimentary texture without showing significant signs of alteration. the sampling for sr isotope analysis from the cingöz and güvenç formations is the most suspicious in terms of diagenetic alteration. due to the sedimentological characteristics of these units (deep sea/continental slope environment), it is challenging to obtain sufficient shell material or primary pure carbonate rock samples. however, a challenge was undertaken by compiling and analysing the marl samples with the highest possible chemical carbonate content. due to the nature of the rocks being easily fragmented, comminution occurred during the preparation of thin sections. therefore, thin sections were prepared using resin. however, in thin section examination, both the cingöz formation (fig. 3g-i) and the güvenç formation (fig. 3j-l) proved to be rich in detritus (15-25%) and show significant alteration traces. this situation can also be seen in sem images of the fossil shells (fig. 4) and geochemical analysis (high fe and mn concentrations). for this reason, the effect of diagenetic alteration was considered for these two units and performed a basic biostratigraphic study to test obtained 87sr/86sr ages for these units. only oyster and gastropod shells were used for sr isotope analysis of the kuzgun formation, which has been abundant in the unit. in the preparation of powder samples from shells, first the outer surface of the shell was washed and dried to minimize any potential alteration. a thin section was prepared in order to determine whether there is widespread alteration in the unit (fig. 3m-o). in the examination, it was observed that the rock is composed of marl (fig. 3m, n) and carbonate mudstone. no secondary mineralization was encountered, and it does not show any significant alteration traces identified from the images. although the laboratory couldn’t measure the sr ratio of the handere formation, the thin-section images of the samples compiled for the handere formation (figs. 3ps) were also examined. these samples are partly fossiliferous in a micrite cement, their primary sedimentary features are preserved and they do not bear any significant alteration traces. however, secondary calcite likely affected the strontium composition somehow, since the unit was highly calcified at some levels. 4.2. geochemical analysis several geochemical analysis techniques are available to evaluate the diagenetic effects in sedimentary rocks postdeposition. to assess the degree of post-depositional changes ta bl e 2. 87 sr /86 sr is ot op ic re su lts a nd c or re sp on di ng a ge ra ng es o f t he a na ly se d sa m pl es w ith li te ra tu re s ou rc es . 3 o f 1 5 sa m pl es w er e re tu rn ed w ith ou t r es ul ts fr om th e la bo ra to ry . s ta nd ar d er ro rs b el on g to th e la st o ne or tw o di gi ts (e .g .: ± 0. 00 00 06 o r ± 0. 00 00 18 ). 8 7 sr /86 sr re su lts c or re ct ed fo r t he n bs 9 87 s ta nd ar d an d w er e m ea su re d as 0 .7 10 26 0± 10 (n =3 ). u ni t sa m pl e co de sa m pl e ty pe 87 sr /86 sr st d er ro r* 87 sr /86 sr a ge ra ng e( m a) /s ta ge li te ra tu re a ge (p al eo nt ol og ic ) h an de re f m . h -1 bu lk ro ck – m ar l n o re su lt n a m er ss in ia n – pl io ce ne (s ch m id t, 1 96 1, g ü rb ü z 19 85 , ü n lü g en ç 19 93 ,). h -2 bu lk ro ck – m ar l n o re su lt n a ku zg un f m . kz -1 o st re a sh el l 0. 70 89 67 ±1 0 7. 4± 2 m a / t or to ni an – m es si ni an la te m io ce ne (s ch m id t, 1 96 1; i̇l ke r, 1 97 5; y a lç in & g ö rü r 19 84 ); to rt on ia n (y et iş , 1 98 8, ö ğ rü n ç , 2 00 1) kz -2 o st re a sh el l 0. 70 91 72 ±1 4 1± 0. 5 m a / p le is to ce ne kz -3 g as tr op od sh el l 0. 70 91 6 ±1 6 1. 3± 0. 7 m a / p lio ce ne – p le is to ce ne l. m io ce ne r ee f c ar bo na te s t1 bu lk ro ck – l im es to ne n o re su lt n a l. m io ce ne /t or to ni an (i lg a r et a l., 2 01 3) t2 bu lk ro ck – l im es to ne 0. 70 89 62 ±1 2 7. 3± 2. 1 m a / t or to ni an – m es si ni an g üv en ç fm . g -1 cl ay ey l im es to ne 0. 70 86 46 ±1 5 16 .9 ± 0. 9 m a / b ur di ga lia n – la ng hi an bu rd ig al ia n – la ng hi an (y et iş , 1 99 4) s er ra va lli an (n a zi k & g ü rb ü z, 1 99 2) . l an gh ia n – se rr av al lia n (n a zi k, 1 98 3, t hi s st ud y) g -2 ca lc ar eo us d et rit ic 0. 70 82 92 ±1 5 22 ±1 .2 m a / a qu ita ni an g -3 ca lc ar eo us d et rit ic 0. 70 81 49 ± 9 25 ± 0. 6 m a / c ha tt ia n ci ng öz f m . c1 ca lc ar eo us d et rit ic 0. 70 88 48 ±1 5 12 ± 2. 1 m a / s er ra va lia n – to rt on ia n la te b ur di ga lia n – ea rly s er ra va lli an (n a zi k & g ü rb ü z, 19 92 ); la te b ur di ga lia n – se rr av al lia n (ş a fa k, 1 99 3) , bu rd ig al ia n – ?s er ra va lli an (t hi s s tu dy ) c2 ca lc ar eo us d et rit ic 0. 70 82 5 ±7 23 ±1 .3 m a / c ha tt ia n – a qu ita ni an c3 cl ay ey l im es to ne 0. 70 82 36 ±1 0 22 .8 ±1 .5 m a / c ha tt ia n – a qu ita ni an ka pl an ka ya /k ar ai sa lı fm . k2 bu lk ro ck – m ar l 0. 70 89 09 ±1 6 10 ± 2. 5 m a / s er ra va lli an – t or to ni an lo w er -m id dl e m io ce ne * (ü n lü g en ç , 1 99 3) , l . b ur di ga lia n – se rr av al lia n (s in ac i, 20 10 ) k4 bu lk ro ck – m ar l 0. 70 89 54 ±1 5 9. 5± 2. 4 m a / s er ra va lli an – t or to ni an g eologia c roatica 69akinci et al.: strontium isotopic stratigraphy of the miocene adana basin (s. anatolia) and its geological implications in carbonate rocks and shells there are several criteria in world practice: mn/sr <1.5 and rb/sr <0.004 (asmerom et al., 1991), mn/sr <1, rb/sr <0.002, and ca/sr <1000 (derry et al., 1992), mn/sr<1.5 and rb/sr<0.0005 (kaufman et al., 1993), mg/ca≤0.024, mn/sr≤0.2, fe/sr≤5.0 (gorokhov et al., 1995; kuznetsov et al., 1997; semikhatov et al., 1998) mg/ca≤0.608, mn/sr≤1.2, fe/sr≤3.0 (kuznetsov et al., 2003). table 1 shows the results of the geochemical analysis for the samples with 87sr/86sr results. in this study, it was evaluated according to kuznetsov et al. (2003, 2012), figure 3. thin-section photomicrographs of bulk-rock samples collected from the field for 87sr/86sr analysis: a) t-1 (tırtar fm.); b-c) t-2 (tırtar fm.); d) k-1 (kaplankaya fm.); e-f) k-2 (kaplankaya fm.); g) c-1 (cingöz fm. (prepared in resin)); h-i) c-3 (cingöz fm.); j) g-1 (güvenç fm. (prepared in resin)), k-l) g-2 (güvenç fm.); m) kz-1 (kuzgun fm. (oyster shells used for sr analysis of kuzgun fm.)), n) kz-2 kuzgun fm.; o) kz-3 (kuzgun fm.); p-r) h-1 (handere fm.), s) h-2 (handere fm.). while the primary diagenetic features seem to be preserved in the kaplankaya and karaisalı formations, an excess of clastic material and some diagenetic differentiation can be observed in the cingöz and güvenç formations. see text for further explanations. g eo lo gi a c ro at ic a 70 geologia croatica 78/1 which is one of the most recent studies in the evaluation of diagenetic alteration. according to the results, it is seen that the mg/ca and fe/sr ratios are very high and may lead to deviations in the 87sr/86sr ratios of the güvenç (mg/camax=0.39; fe/ srmax=15.71) and cingöz formations (fe/srmax=30.52). exceptionally high mn concentrations were observed in two samples (kz-2, kz-3) from oyster and gastropod shells collected from the kuzgun formation (5.23 and 3.46 mn/sr, respectively). the geochemical results for other units were within or near acceptable limits. geochemical analysis results are generally consistent with petrographic and sem data, suggesting that reliable 87sr/86sr results are hindered in clastic sedimentdominated units (e.g., güvenç and cingöz formations). early marine diagenesis is also a critical stage in the diagenetic history of shallow-water carbonate sediments, playing a key role in the transformation of metastable caco3 polymorphs, e.g. aragonite and high-mg calcite, into the stable low-mg calcite (higgins et al., 2018). although it leaves subtle textural evidence, it significantly impacts primary geoche mical signatures, altering stable isotopic ratios and elemental com positions, which is crucial for interpreting sedimentary records. the chemical evolution of pore fluids during early marine diagenesis and their interaction with sediment composition are central to the mineralogical and geochemical changes observed in ancient shallow-water carbonate sediments. this process may have caused variations in the sr isotope ratios of units deposited in the basin, particularly during the upper miocene and pliocene. 5. results the general stratification in the adana basin is oriented eastwest and dips southward. sampling and cross-section measure ments for strontium analysis and stratigraphic interpre tation were carried out approximately along a north-south oriented section within the adana basin (fig. 1). thus, the results aimed to minimize the influence of lateral facies changes. the selected sections are the locations where the units present their typical characteristics. when collecting sr samples, there was a general attempt to compile a selection from different stratigraphic levels of the unit. sedimentary figure 4. sem images of fossil shells found in the güvenç (above – globigerinoides sp.) and cingöz (below – orbulina suturalis) formations. images indicate that the units considerably affected by alteration marked by significantly etched surfaces; indistinct and fused nacreous tablets. also secondary calcification can be seen in right bottom image (mag=4000x). g eologia c roatica 71akinci et al.: strontium isotopic stratigraphy of the miocene adana basin (s. anatolia) and its geological implications figure 5. representative outcrop photos of various geological formations showing their in-situ lithological characteristics and stratigraphic relationships in the adana basin: a,c,d) outcrop view of the kaplankaya and l. miocene reef carbonates at ne of karaisalı district (please note that the faulting in kaplankaya fm. does not affect the overlying late miocene reef carbonates); b) sandstone-siltstone-shale alternations of the cingöz fm. from east of nergizlik village; e) road-cut exposure of the güvenç fm. near the güvenç village; f) outcrop view of the kuzgun fm. at the south of salbaş village; g) close view of the late miocene reef limestones including algae prints. g eo lo gi a c ro at ic a 72 geologia croatica 78/1 logs were taken from places where sampling was undertaken and where the characteristics of the units could be clearly observed and are presented separately for each unit below. 5.1. the kaplankaya formation sampling and stratigraphic logging for the kaplankaya formation (figs. 5a, c, d) was undertaken around the village of gülüşlü (36 s 679674.39 d e/ 4127318.27 m n). along the section, the kaplankaya formation is overlain by the late miocene reefal limestones and has a thickness of around 4050 metres. field observations were performed along a road cut between the villages of karaisalı and gülüşlü. the unit consists of mudstone and marls containing lamellibranch and conus shells. three samples (marl) were collected for strontium analysis throughout the investigated section. the two studied sedimentary sections of the kaplankaya formation are shown in figure 6. the 87sr/86sr result of one of the three samples of the kaplankaya formation could not be successfully obtained in the laboratory. the available 87sr/86sr age data of the two other samples yielded ages 9.5±2.4 ma and 10±2.5 ma coinciding the serravallian–tortonian interval (fig. 7e). figure 6. measured sedimentological logs of the kaplankaya formation showing the sampling levels (k-2 at left and k-4 at right) for the sr analysis (see fig. 1 for locations). g eologia c roatica 73akinci et al.: strontium isotopic stratigraphy of the miocene adana basin (s. anatolia) and its geological implications 5.2. the cingöz formation stratigraphic logging and sampling for 87sr/86sr analysis of the cingöz formation (figs. 5b, 8) were performed along with the road cuts on the main road connecting the karaisalı district centre to the village of kızıldağ in the northeast (36 s 683730.00 d e / 4131183.00 m n). samples were collected from three different stratigraphic levels; from the contact with the overlying güvenç formation in the south and towards the lowest levels of the unit in the north (c1-bottom, c2-middle, c3-top in fig.1). this section constitutes the western submarine fan of the turbiditic cingöz formation. a fining upward trend in grain size of the unit comprising alternations of sandstone, shale, and marl was observed along the section towards the distal zone to the south. the studied sedimentary sections of the cingöz formation are presented in figure 8. sr isotope analysis results derived from the samples collected from the cingöz formation (table 2), yielded ages ranging from 23±1.3 ma (chattian–aquitanian) to 12±2.1 ma (serravallian–tortonian) (youngest) (fig. 7d). to assess the compatibility of the 87sr/86sr ages, biostrati gra phic dating was applied to samples collected from the cingöz formation due to the high clastic content and diagenetic altera tion. in the samples compiled from the unit; neomono­ ceratina cf. mouliana, cyamocytheridea sp., neomonoceratina figure 7. graphs showing the obtained 87sr/86sr isotopic age data for all the units studied, presented on the sr variation curve of mcarthuret al. (2001); a) kuzgun fm.; b) l. miocene reef carbonates; c) güvenç fm.; d) cingöz fm.; e) kaplankaya fm. g eo lo gi a c ro at ic a 74 geologia croatica 78/1 sp., thalmannia hodgii, tenedocythere prava, acantocythereis hystrix, orbulina suturalis, orbulina universa, orbulina bilo­ bata, globigerinoides bollii species were identified which are all indicative of a wide ranging burdigalian–serravallian interval (fig. 9). 5.3. the güvenç formation sampling for strontium isotope analyses and sedimentary logging of the güvenç formation (figs. 5e, 10) were performed along the highway between güvenç village in the karaisalı district (location of the type section of the unit), and the village of kuzgun in the south. composed of loosely consolidated clay and shale, highly susceptible to erosion, the güvenç formation can only be clearly observed in the newly opened road cuts and small galleries along this road. for the strontium isotope analysis, three samples were selected; one near the contact with the underlying cingöz formation (g-3) (36 s 683100.00 d e/ 4125229.00 m n), one from the uppermost levels (36 s 685916.00 d e/ 4113848.00 m n), and one from the middle levels (g-2) (figs. 1,10). the recorded 87sr/86sr ages of the güvenç formation are presented in figure 7 and table 2. isotopic analysis of sample g-3, collected near the basal levels of the unit (just above the cingöz fm.) is 25±0.6 ma (chattian) and the sample collected from the middle level is 22±1.2 ma (chattian–aquitanian). the sample g-1, collected from the uppermost levels of the unit, near its contact with the overlying kuzgun formation, yielded an age of 16.9±0.9 ma representing burdigalian– langhian interval (fig. 7c). biostratigraphic analysis was conducted to compare with the strontium isotope results, since the güvenç formation exhibits a high clastic content, similar to the cingöz formation and diagenetic alteration was detected in the thin section examinations. in the samples collected from the unit, globi­ gerinoides bollii, globigerinoides subquadratus, globi geri no­ ides sp., globorotalia mayeri, globigerinella obesa, globo ge­ rino ides trilobus, globigerinoides cf. sacculifer, globiquadriana figure 8. sedimentological logs measured from the cingöz formation showing the levels of the sampling for sr analysis (see figure 1 for locations). g eologia c roatica 75akinci et al.: strontium isotopic stratigraphy of the miocene adana basin (s. anatolia) and its geological implications dehiscensis and sphaeroidinellopsis sp. species were determined which are all indicative of the langhian–serravallian interval (fig. 11). 5.4. the late miocene reef carbonates given the younger age of the sampled reef carbonate rocks in the vicinity of gülüşlü village (nw karaisalı – 36°s 679945.00 e/4127388.00 n) (fig. 1), they were considered and classified as “late miocene reef carbonates”. in this region, the reef carbonates are observed superimposed on the kaplankaya formation (figs. 5a, c, d, g). the stratigraphic log measured from the sampling site reveals that the approximately 6 metrethick, pale yellow to beige coloured neritic (reefal) carbonate rocks overlie the clastic sediments of the kaplankaya figure 9. sem images of the micro-fauna identified in the cingöz formation. 1 – neomonoceratina cf. mouliana (shell, left external view); 2 – neomonoceratina cf. mouliana (shell, left external view); 3 – cyamocytheridea sp. (shell, left external view); 4 – neomonoceratina sp. (shell, right external view); 5 – thalmannia hodgii (right carapace, external view); 6 – tenedocythere prava (left carapace, external view); 7 – acantocythereis hystrix (right carapace, external view); 8 – orbulina suturalis; 9 – orbulina suturalis; 10 – orbulina suturalis; 11 – orbulina universa; 12 – orbulina universa; 13 – orbulina bilobata; 14 – orbulina bilobata; 15 – globigerinoides bollii. g eo lo gi a c ro at ic a 76 geologia croatica 78/1 formation consisting mainly of marls and mudstones. the studied and sampled section is shown in figure 12. the 87sr/86sr results were not obtained for one of the two samples (t-1) compiled from the late miocene carbonates. the 87sr/86sr results of the other sample yielded an age of 7.3±2.1 ma (tortonian–messinian) (fig. 7b). 5.5. the kuzgun formation sedimentary logging of the kuzgun formation (figs. 5f, 13) and sampling for strontium analysis were carried out along the road linking the northern parts of the karahan neighbourhood in the north-eastern part of adana city centre and the kuzgunabdullu villages in the north. one sample (kz-1) (36 s 693185.00 d e/ 4106400.00 m n) was milled from a bivalve shell collected from the fine clastic sediments at the lowermost levels of the formation, (memişli member) and another sample selected from the kuzgun member (kz-2) representing the upper levels. sample kz-3 was prepared from a gastropod shell obtained from the deltaic-shallow marine clastic rocks of the memişli member (36 s 687733.00 d e/4109777.00 m n). sample kz-1 was milled from a large oyster shell collected from the underlying fine-grained shallow marine-fluvial clastics of the kuzgun member (36 s 687241.00 d e/4110947.00 m n). the strontium isotope ages of three samples collected from different levels of the kuzgun formation are given in figure 6. while the kz-1 sample indicates a tortonian–early messinian age (7.4±2 ma), the results for the kz-2 and kz-3 samples are inconsistent, suggesting pliocene–pleistocene ages (1±0.5 ma and 1.3±0.7 ma). 5.6. handere formation sedimentary logging and sampling studies of the handere formation were carried out along road cuts and galleries along the kabasakal, şambayadı, and karahan quarters located in the north-eastern part of adana city centre. two samples were selected for strontium analysis. sample h-1 was obtained from the middle part of the formation stratigraphically (36 s 697669.00 d e/ 4103394.00 m n) and sample h-2 was collected near the uppermost levels (36 s 695176.00 d e / 4102323.00 m n). both samples were collected from the limestone, clayey-limestone interbeds in the unit, however, the sr isotope results for these samples were not successfully obtained from the laboratory. 6. geological implications and discussion 6.1. kaplankaya-karaisalı formations and l. miocene carbonates the 87sr/86sr ages of the kaplankaya formation exhibiting lateral and vertical transitions into the karaisalı formation, figure 10. sedimentological logs measured from the güvenç formation showing the levels of the sampling for sr analysis (g-1,2,3) (see figure 1 for locations). g eologia c roatica 77akinci et al.: strontium isotopic stratigraphy of the miocene adana basin (s. anatolia) and its geological implications indicate serravallian–tortonian ages (9.5±2.4 ma to 10±2.5 ma) (fig. 7). reported to contain abundant foraminifera such as borelis melo fichtel & moll, borelis curdica reichel, amphistegina sp., and rotalia sp., the karaisalı formation was palaeontologically assigned a burdigalian– langhian age (11-20 ma) by si̇rel & gündüz (1981); which makes our sr isotope-derived ages slightly younger in comparison. ünlügenç & demi̇rkol (1988) and özalp (1993) assigned an early-middle miocene age to the kaplankaya formation based on its fossil content compiled from the unit. the age data from the literature are, on average, several million years older than the 87sr/86sr ages we obtained in this figure 11. sem images of the microfauna identified in the güvenç formation. 1 – globigerinoides bollii; 2 – globigerinoides subquadratus; 3 – globigerinoides sp.; 4 – globigerinoides sp.; 5 – globorotalia mayeri; 6 – globorotalia mayeri; 7 – globorotalia mayeri; 8 – globigerinella obesa; 9 – globigerinella obesa; 10 – globogerinoides trilobus (umbilical view); 11 – globogerinoides trilobus (umbilical view); 12 – globogerinoides trilobus (umbilical view); 13 – globigerinoides cf. sacculifer; 14 – globiquadriana dehiscensis; 15 – sphaeroidinellopsis sp. g eo lo gi a c ro at ic a 78 geologia croatica 78/1 study. since no significant diagenetic alteration was observed in the collected samples, two options can be considered to explain this low 87sr/86sr ratio. first, the age data obtained from these reef carbonates are consistent with the tırtar formation (middle-late miocene reef carbonates), which is identified in the mut basin (ilgar et al., 2013) located to the west of the adana basin. therefore, these young reef sediments observed in the adjacent basin may have been deposited as thin layers over the slightly older middle–upper miocene karaisalı formation in the western regions of the adana basin. the sr isotope age data suggest that reef formation in the adana basin persisted not only in the lower and middle miocene but also in the upper miocene. the carbonate rocks found south of the karaisalı district which exhibit a patchy distribution in the adana basin, should be younger than the northern reef carbonates (karaisalı fm.), typically located at much higher elevations as steep cliffs. the shallow-marine and/or reefal carbonates of the late miocene were deposited directly on the karaisalı and kaplankaya formations by a short term transgression along the basin margin (fig. 14). a second option may be linked to continental run-off, although a minor influence from a secondary source to kaplankaya/karaisalı formations deposited near the shoreline. fluctuations in the 87sr/86sr ratio in the catchment may be attributed to the influence of continental run-off derived low 87sr/86sr weathered from the basement units including palaeozoic– mesozoic ophiolites and carbonate rocks. early marine diagenesis is also a critical stage in the diagenetic history of shallow-water carbonate sediments, significantly contributing to the transformation of metastable caco3 polymorphs, such as aragonite and high-mg calcite, into the stable low-mg calcite (higgins et al., 2018). however, early marine diagenetic alteration is difficult to identify using either petrographic analysis or other conventional methods. ahm et al. (2018) developed a model that quantifies the resetting of δ44/40ca, δ26mg, δ13c, and δ18o in combination with elemental concentrations of sr during neomorphism (aragonite-to-calcite), recrystallization (calcite-to-calcite), and dolomitization (calcite-to-dolomite). various conventional techniques such as ftir spectroscopy, xrd, and sem are employed to differentiate between calcium carbonate polymorphs. although sem figure 12. sedimentological log of the late miocene reefal carbonates measured around the t-1 and t-2 sample site (see figure 1 for location). g eologia c roatica 79akinci et al.: strontium isotopic stratigraphy of the miocene adana basin (s. anatolia) and its geological implications analyses were conducted in this study, sem does not provide definitive results in discerning calcium carbonate polymorph variations because the morphology of each calcium carbonate polymorph is not unique. however, the exact impact of this transformation on the geochemical composition of the rock remains to be fully elucidated. 6.2. the cingöz and güvenç formations the 87sr/86sr analysis results of the cingöz formation (table 2) yielded ages that range from 23±1.3 ma (oldest) (chattian– aquitanian) to 12±2.1 ma (youngest) (serravallian–tortonian) (fig. 10). according to the biostratigraphic literature, the cingöz formation has been assigned the following age ranges: burdigalian to serravallian (demi̇rtaşli & genç, 1986), langhian–serravallian (görür, 1979; yalçin & görür, 1984) and burdigalian–langhian (yeti̇ş & demirkol, 1986). a micro-palaeontological study carried out by nazik & gürbüz (1992) documented a comprehensive micro-fossil analysis of the entire turbiditic cingöz formation reporting that it was deposited during the late burdigalian–serravallian interval. a supportive fundamental biostratigraphic study was conducted in the locations where sr sampling was carried out, as diagenetic alterations detected petrographically and geochemically in the samples could potentially cause alterations of the original 87sr/86sr compositions of the unit. the genera and species identified in the unit generally indicate the burdigalian–?serravallian interval (fig. 9). it has been inferred that one of the three 87sr/86sr age data is consistent with the literature (12±2.1 ma – serravallian) and our biostratigraphic study; however, the other two sr results (derived from lower parts of the unit) (22-23 ma – aquitanian) show a difference of approximately 3-4 m (older) from the proposed lower age limit for the unit. this situation may have occurred due to diagenetic alteration within the unit. the 87sr/86sr analyses of the güvenç formation indicate ages ranging from 25±0.6 ma to 16,9±0.9 ma corresponding to chattian–langhian interval (table 2, fig. 7). however, biostratigraphic literature (nazik & toker, 1986; ünlügenç, 1993) provide langhian–serravallian (16-11 ma) age for the unit. the palaeontological determinations made in this study also show that the age of the unit is langhian–serravallian. thus, it was understood that there was a considerable difference in two out of three 87sr/86sr ages (about 10 ma) thought to be caused by diagenetic alteration (high mg/ca and fe/sr) in the güvenç formation similar to that observed in the cingöz formation, while one age data is roughly consistent with the biostratigraphical ages. the possibility that the sr results, which are consistent with figure 13. sedimentological logs measured from the kuzgun formation showing the sample levels for sr analysis (kz-1,2,3) (see figure 1 for locations). g eo lo gi a c ro at ic a 80 geologia croatica 78/1 biostratigraphic ages, also coincidentally provide coherent ages cannot be ignored. correlations of prepared sr isotope composition against mn/sr, fe/sr, mg/ca (fig. 15) shows that there is no remarkable correlation between sr isotope composition and mn/sr, while there is a moderately negative correlation between mg/ca and fe/sr. the decrease in sr isotope ratios with the increase in fe and mn presented a significant negative linear correlation, which could explain the effect of contamination, especially for the güvenç and cingöz formations. due to the sedimentary characteristics of the güvenç and cingöz formations that contain a high volume of detritus even at their carbonate dominated levels, and groundwater flow along their fractures, significant changes have occurred in their 87sr/86sr composition. since these units contain only sub-millimetre scale micro-fauna, they do not allow for a convenient sr analysis using fossil shells. another important factor to consider in sr isotope studies in the eastern mediterranean region is the highly complex oceanographic evolution of the mediterranean in the miocene period. during this period, global and local controlling factors on seawater chemistry significantly influenced carbonate production related to the palaeoceanographic conditions of the mediterranean and their changes over time. aquitanian sr and nd isotope records of the mediterranean indicate an open marine basin, influenced by the indian ocean and characterized by a predominant westward circulation, which is sensitive to global climate changes and carbon cycle disturbances. starting from the late burdigalian, the gradual shallowing and intermittent connection with the indian ocean altered the overall circulation in the basin, resulting in longer residence times of mediterranean waters and reduced water exchanges not only with the indian but also the atlantic oceans (kocsis et al., 2008; cornacchia et al., 2021). in this palae oce anographic setting, regional factors such as volcanism had a greater effect on mediterranean seawater chemistry compared to previous periods. thus, the sr isotope record of the eastern mediterranean could deviate towards lighter sr isotope values. figure 14. schematic geological model summarising the inferred sedimentological development of the adana basin for late burdigalian to messinian period. g eologia c roatica 81akinci et al.: strontium isotopic stratigraphy of the miocene adana basin (s. anatolia) and its geological implications 6.3. the kuzgun formation according to the 87sr/86sr age data obtained from the basal levels of the kuzgun formation, the unit began to be deposited about 7.4±2 ma. inconsistencies were observed in the sr ages of the kuzgun formation, analysed from the fossil shells. the kz-1 sample points to the early messinian, highly compatible with palaeontological literature (e.g., darbaş & nazi̇k, 2010; cipollari et al., 2013). a substantial biostratigraphical study of faranda et al. (2013) constrains the upper part of the kuzgun formation to the early messinian. however, the results for the kz-2 and kz-3 samples are inconsistent and point to a pleistocene age (~1 ma). this could be due to several reasons. one probable cause is the change in strontium ratios due to the surface-alteration in the fossil shells (oyster/ gastropod) where the sampling was made. however, geochemical analyses of the oyster and gastropod shell specimens (kz-2 and kz-3) collected from the unit yielded high mn/sr ratios indicating that they were subjected to diagenetic alteration. on the other hand, if oyster shells are formed by calcite layers they can be suitable for sr isotope dating but if they have porous shell layers and/or have irregular and chalky deposits this may cause deviations from the original sr ratios (scasso et al., 2001). this high supergene manganese concentration, which is also reflected in the fossil shells, may be a clue to the distribution of manganese in the underlying parent rocks (force & cox, 1991). manganese may have been transported from depth to a surface of precipitation along local faults (stead & stose, 1943; cooper, 1944). mesozoic– palaeozoic bedrocks of the adana basin including dolomitic rocks and quartzite (demirkazık, yerlikaya, karahamzauşağı formations) are the most likely candidates as sources of high mn concentrations. manganese enrichment in carbonates may also occur during the early diagenetic microbial reduction of manganese oxides (torres et al., 2014). the observed accumulation of manganese in these sediments is considered a significant indicator of early diagenetic microbial reduction, where anaerobic microbial communities utilize manganese oxides as electron acceptors in their metabolic processes. this reduction process, taking place in anaerobic environments, plays a pivotal role in influencing the cycling of manganese in marine sediments, consequently impacting the bioavailability of other essential nutrients. in such an anaerobic basin, iron precipitation can be associated with sulfate reduction and the metabolic activities of iron bacteria; during these processes, iron (fe³⁺) is concurrently reduced and precipitates in an insoluble form, particularly through interactions among methanogenic and sulfate-reducing microorganisms. figure 15. diagrams (cartesian coordinates and trendlines) showing the correlation between sr isotope composition versus mn/sr, fe/sr, mg/ca ratios for all the analysed samples. figure 16. a simplified palinspastic map of the study region (adana basin) representing inferred environmental conditions during the late miocene. g eo lo gi a c ro at ic a 82 geologia croatica 78/1 87sr/86sr ratios may deviate from the global reference curve due to restricted water exchange between a basin and the global ocean, which could be the case for the upper miocene succession of the adana basin. the deposition of the handere and kuzgun formations was closely affected by the lago-mare (messinian) salinity crisis (from 5.96 to 5.33 ma; krijgsman et al., 1996) in the mediterranean during the late miocene. the lago-mare scenario of terrestrial sedimentation in a dried-up mediterranean basin has a unique baselevel history and water chemistry of sub-basins (cipollari et al., 2013; maillard et al., 2014; micallef et al., 2019; caruso et al., 2020; kartveit et al., 2019; madof et al., 2019; raad et al., 2021). a strontium influx into the lagoonal or lacustrine scenario was derived from drainage within each catchment. the 87sr/86sr ratio of each water source is related to the lithologies weathered in the watersheds and the sr ratio of the resulting basin reflects all these inputs (bataille et al., 2012; doebbert et al., 2014; baddouh et al., 2016). for the lagoonal scenario (şafak et al., 2021), each individual basin receives an additional water source, which was supplied from the major peri-mediterranean drainage systems (e.g., the nile, rhone, and po; griffin, 2002) and, probably, the atlantic as well (vasiliev et al., 2017; garcía-veigas et al., 2018; grothe et al., 2020; andreetto et al., 2021). by examining a significant number of 87sr/86sr analyses conducted on oyster and foraminifera samples from the central and eastern mediterranean basins, schildgen et al. (2014) suggest that a few million years before the messinian salinity crisis, 87sr/86sr in the basins fell below the global values, probably related to basin shallowing and tectonic uplift. during the messinian salinity crisis, the composition of 87sr/86sr from centrally located basins falls below global seawater values. this greater sensitivity to lowered sea level compared to higher continental flow may be related to the inverse relationship between sr concentration and river discharge. cipollari et al. (2013) and faranda et al. (2013) have shown several evidence of the flooding and subsequent surface uplift in the messinean–zanclean period indicating that environmental conditions in the basin were quite unstable during this period. local volcanism in a region also generally tends to lower the sr isotopic ratio due to injecting high amounts of light sr. the volcanic/tuffitic level called the salbaş tuffite member within the kuzgun formation is exposed in the adana basin. the source of this volcanism was shown by nurlu et al. (2021) to be an area in the north, and it may have deviated the original sr ratio in the units deposited during the middle– upper miocene period. although the authors determined ages ranging from 20 to 27 ma, based on strontium age analysis for the carbonate-rich tuffite levels in the kuzgun formation, they suggested that they must have been deposited within an earlier marine basin originally, and then transported and re-deposited. 6.4. the handere formation 87sr/86sr data could not be obtained from the samples collected from the handere formation although they do not show any significant diagenetic alteration. since this unit was generally deposited under terrestrial-transitional conditions, it can be thought that the terrestrial feed of the limited shallow marine basin affected the natural strontium ratio. however, the 7 ma age data obtained from the sample collected from the base levels of the overlying kuzgun formation, sheds light on the fact that the unit is younger than 7 ma. although the thin section analysis revealed no significant alteration traces, calcification known to be common throughout the unit has likely greatly affected the strontium content of the unit. 7. conclusion this study presents the first integrated 87sr/86sr chemogeologic investigation for six different formations in the adana basin, where fifteen samples were systematically collected and analysed. according to the recorded 87sr/86sr results, ages of 9.5±2.4 ma and 10±2.5 ma (serravallian–tortonian) were determined for the kaplankaya/karaisalı formation, while ages of 23±1.3 ma (chattian–aquitanian) to 12±2.1 ma (serravallian) were found for the cingöz formation, 25±0.6 ma (chattian) to 16.9±0.9 ma (burdigalian–tortonian) for the güvenç formation. the deviations in 87sr/86sr results from the cingöz and güvenç formations, which are dominated by clastic deposits (marl), are attributed to diagenetic alteration diagnosed by geochemical analysis. supportive biostra tigraphi cal studies on these units showed that the ages of these units were langhian–serravallian and burdigalian–serravallian, respectively. the deviation in two out of three 87sr/86sr age data obtained from the kuzgun formation may also be due to diagenetic alteration. it was determined that the thin reef carbonates, observed on an unconformity above the kaplankaya formation are tortonian–messinian (7.3±2.1 ma) in age. this indicates that the marine conditions did not completely recede from the basin in the early tortonian and marine influxes have taken place in short-term/multi-phases (episodic), resulting in the formation of younger reef sediments in the southern parts of the basin (fig. 16). although the recorded sr isotopic data do not coincide well with the literature, this study provides an important basis for further detailed isotopic research in the region, highlighting the geological implications that were revealed. acknowledgement author would like to thank the department of scientific research projects of çukurova university (adana, turkey) for financial support for this study (project no: fba-2020-13028). for help on palaeontological study, i would like to thank prof. dr. ümit şafak and hande sonsun. author would like to express sincere gratitude to the anonymous reviewers for their valuable feedback and constructive suggestions, which significantly contributed to the development of this paper. references ahm, a-s.c., bjerrum, c.j., blättler, c.l., swart, p.k. & higgins, j.a. (2018): quantifying early marine diagenesis in shallow-water carbonate sediments.– geochimica et cosmochimica acta, 236, 140– 159. https://doi.org/10.1016/j.gca.2018.02.042 akinci, a.c. & ünlügenç, u.c. (2021): neogene tectonic evolution of the misis-andırın-engizek range: structural and sedimentary evidences from bulgurkaya sedimentary mélange.– arabian journal of geosciences, 14/7, 655. https://doi.org/10.1007/s12517-021-06991-x g eologia c roatica 83akinci et al.: strontium isotopic stratigraphy of the miocene adana basin (s. anatolia) and its geological implications akinci, a.c., nurlu, n. & güney, a. (2023): origin and geodynamic implications of basaltic rocks intercalated with miocene turbidites around the i̇skenderun basin (eastern mediterranean/turkey).– journal of african earth sciences, 198, 104780. https://doi.org/10.1016/j.jafrearsci.2022.104780 al-aasm, i.s. & veizer, j. (1986): diagenetic stabilization of aragonite and low-mg calcite; i, trace elements in rudists.– journal of sedimentary research, 56, 138–152. https://doi.org/10.1306/212f88a5-2b2411d7-8648000102c1865d albora, a.m., sayin, n. & uçan, o.n. (2006): evaluation of tectonic structure of i̇skenderun basin (turkey) using steerable filters.– marine geophysical researches, 27, 225–239. https://doi.org/10.1007/s11001006-9002-5 andreetto, f., matsubara, k., beets, c.j., fortuin, a.r., flecker, r. & krijgsman, w. (2021): high mediterranean water-level during the lago-mare phase of the messinian salinity crisis: insights from the sr isotope records of spanish marginal basins (se spain).– palaeogeography, palaeoclimatology, palaeoecology, 562, 110139. https:// doi.org/10.1016/j.palaeo.2020.110139 argentino, c., reghizzi, m., conti, s., fioroni, c., fontana, d. & salocchi, a.c. (2017): strontium isotope stratigraphy as a contribution for dating miocene shelf carbonates (s. marino fm., northern apennines).– rivista italiana di palaeontologiia e stratigrafia, 123, 39– 50. asmerom, y., jacobsen, s.b., knoll, a.h., butterfield, n.j. & swett, k. (1991): strontium isotopic variations of neoproterozoic seawater: implications for crustal evolution.– geochimica et cosmochimica acta, 55, 2883–2894. https://doi.org/10.1016/0016-7037(91)90453-c atabey, e., atabey, n., hakyemez, a., i̇slamoğlu, y., sözeri, ş., özçelik, n.n., saraç, g., ünay, e. & babayiğit, s. (2000): lithostratigraphy and sedimentology of the miocene basin between mut-karaman [mut-karaman arası miyosen havzasının litosratigraisi ve sedimantolojisi – in turkish].– bulletin of mineral research and exploration, 122, 53–72. baddouh, m.b., meyers, s.r., carroll, a.r., beard, b.l. & johnson, c.m. (2016): lacustrine 87sr/86sr as a tracer to reconstruct milankovitch forcing of the eocene hydrologic cycle.– earth and planetary science letters, 448, 62–68. barka, a.a. & kadinsky-cade, k. (1988): strike-slip fault geometry in turkey and its influence on earthquake activity.– tectonics, 7, 663– 684. https://doi.org/10.1029/tc007i003p00663 bataille, c.p., laffoon, j. & bowen, g.j. (2012): mapping multiple source effects on the strontium isotopic signatures of ecosystems from the circum‐caribbean region.– ecosphere, 3, 1–24. brand, u. & veizer, j. (1980): chemical diagenesis of a multicomponent carbonate system 1. trace elements.– journal of sedimentary petrology, 50, 1219–1236. https://doi.org/10.1306/212f7bb7-2b24-11d78648000102c1865d brandano, m. & policicchio, g. (2012): strontium stratigraphy of the burdigalian transgression in the western mediterranean.– lethaia, 45, 315–328. http://doi.org/10.1111/j.1502-3931.2011.00285.x brass, g.w. (1976): the variation of the marine 87sr86sr ratio during phanerozonic time: interpretation using a flux model.– geochimica et cosmochimica acta, 40, 721–730. broeker, w.s. & peng, t.h. (1982): tracers in the sea.– eldigio press lamont doherty geological observatory, 690p. burke, w., denison, r., hetherington, e., koepnick, r., nelson, h. & otto, j. (1982): variation of seawater 87sr/86sr throughout phanerozoic time.– geology, 10, 516–519. http://dx.doi.org/10.1130/0091-7613(1982)10%3c516:vosstp%3e2.0.co;2 burton-ferguson, r., aksu, a., calon, t. & hall, j. (2005): seismic stratigraphy and structural evolution of the adana basin, eastern mediterranean.– marine geology, 221, 189–222. http://dx.doi.org/10.1016/j.margeo.2005.03.009 cai, y., you, c., wu, s., cai, w. & guo, l. (2020): seasonal variations in strontium and carbon isotope systematics in the lower mississippi river: implications for chemical weathering.– chemical geology, 553, 119810. https://doi.org/10.1016/j.chemgeo.2020.119810 caruso, a., blanc-valleron, m.m., da prato, s., pierre, c. & rouchy, j.m. (2020): the late messinian “lago-mare” event and the zanclean reflooding in the mediterranean sea: new insights from the cuevas del almanzora section (vera basin, south-eastern spain).– earth-science reviews, 200, 102993. https://doi.org/10.1016/j.earscirev.2019.102993 cipollari, p., cosentino, d., radeff, g., schildgen, t.f., faranda, c., grossi, f., gliozzi, e., smedile, a., gennari, r., darbaş, g., dudas, f., gürbüz, k., nazik, a. & echtler, h. (2013): easternmost mediterranean evidence of the zanclean flooding event and subsequent surface uplift: adana basin, southern turkey.– geological society of london special publications, 372, 615. https://doi. org/10.1144/sp372.5 cooper, b.n. (1944): geology and mineral resources of the burkes garden quadrangle, virginia.– virginia geological survey bulletin, 60, 299 p. cornacchia, i., brandano, m. & agostini, s. (2021): miocene palaeoceanographic evolution of the mediterranean area and carbonate production changes: a review.– earth-science reviews, 221, 103785. https://doi.org/10.1016/j.earscirev.2021.103785 darbaş, g. & nazik, a. (2010): micropalaeontology and palaeoecology of the neogene sediments in the adana basin (south of turkey).– journal of asian earth sciences, 39/3, 136–147. https://doi.org/10.1016/j.jseaes.2010.03.002 demirtaşli, e. & genç, m. (1986): final report of the tectonic investigation between the akkuyu site, silifke-mersin-tarsus coastal area, adana and iskenderun basins, ecemiş fault zone, bolkar mountains, ereğli-ulukışla basins and eastern part of the mut basin.– general directorate of mineral research and exploration, 59, 248 p. derman, a.s. & gürbüz, k. (2007): nature, provenance and relationships of early miocene palaeovalley fills, northern adana basin, turkey: their significance for sediment-bypassing on a carbonate shelf.– turkish journal of earth sciences, 16, 181–209. derry, l.a., kaufman, a.j. & jacobsen, s.b. (1992): sedimentary cycling and environmental change in the late proterozoic: evidence from stable and radiogenic isotopes.– geochimica et cosmochimica acta, 56, 1317–1329. https://doi.org/10.1016/0016-7037(92)90064-p dewey, j.f. & şengör, a.m.c. (1979): aegean and surrounding regions: complex multiplate and continuum tectonics in a convergent zone.– gsa bulletin, 90, 84–92. https://doi.org/10.1130/0016-7606(1979)90<84:aasrcm>2.0.co;2 dewey, j.f., hempton, m.r., kidd, w.s.f., şaroglu, f. & şengör, a.m.c. (1986): shortening of continental lithosphere: the neotectonics of eastern anatolia – a young collision zone.– geological society of london special publications, 19, 404. https://doi.org/10.1144/gsl. sp.1986.019.01.22 doebbert, a.c., johnson, c.m., carroll, a.r., beard, b.l., pietras, j.t., carson, m.r., norsted, b. & throckmorton, l.a. (2014): controls on sr isotopic evolution in lacustrine systems: eocene green river formation, wyoming.– chemical geology, 380. https:// doi.org/10.1016/j.chemgeo.2014.04.008 elderfield, h. (1986): strontium isotope stratigraphy.– palaeogeography, palaeoclimatology, palaeoecology, 57, 71–90. ht tps://doi. org/10.1016/0031-0182(86)90007-6 faranda, c., gliozzi, e., cipollari, p., grossi, f. & darbaş, g. (2013): messinian palaeoenvironmental changes in the easternmost mediterranean basin: adana basin, southern turkey.– turkish journal of earth sciences, 22, 839–863. https://doi.org/10.3906/yer-1205-11 flecker, r. & ellam, r. (2006): identifying late miocene episodes of connection and isolation in the mediterranean–parathyan realm using sr isotopes.– sedimentary geology, 188, 189–203. https://doi.org/10.1016/j.sedgeo.2006.03.005 force, e.r. & cox, l.j. (1991): manganese contents of some sedimentary rocks of palaeozoic age in virginia.– united states geological survey, 1916, 42. https://doi.org/10.3133/b1916 g eo lo gi a c ro at ic a 84 geologia croatica 78/1 garcía-veigas, j., cendón, d.i., gibert, l., lowenstein, t.k. & artiaga, d. (2018): geochemical indicators in western mediterranean messinian evaporites: implications for the salinity crisis.– marine geology, 403, 197–214. http://dx.doi.org/10.1016/j.margeo.2018.06.005 gealey, w.k. (1988): plate tectonic evolution of the mediterranean-middle east region.– tectonophysics, 155, 285–306. https://doi. org/10.1016/0040-1951(88)90270-3 gleason, j.d., moore, t.c., rea, d.k., johnson, t.m., owen, r.m., blum, j.d., hovan, s.a. & jones, c.e. (2002): ichthyolith strontium isotope stratigraphy of a neogene red clay sequence: calibrating eolian dust accumulation rates in the central north pacific.– earth and planetary science letters, 202, 625–636. https://doi.org/10.1016/ s0012-821x(02)00827-0 gorokhov, i., semikhatov, m.a. & baskakov, a.v. (1995): sr isotopic composition in riphean, vendian, and lower cambrian carbonates from siberia.– stratigrafiya geologicheskaya korrelyatsiya, 3, 3–33. görür, n. (1979): sedimentology of the karaisalı limestone [karaisalı ki­ reçtaşının (miyosen) sedimantolojisi – in turkish].– bulletin of the geological society of turkey, 22, 227–234. griffin, d.l. (2002): aridity and humidity: two aspects of the late miocene climate of north africa and the mediterranean.– palaeogeography, palaeoclimatology, palaeoecology, 182, 65–91. https://doi.org/10.1016/ s0031-0182(01)00453-9 grothe, a., andreetto, f., reichart, g.j., wolthers, m., van baak, c.g.c., vasiliev, j., stoica, m., sangiorgi, f., middelburg, j.j., davies, g.r. & krijgsman, w. (2020): paratethys pacing of the messinian salinity crisis: low salinity waters contributing to gypsum precipitation?– earth and planetary science letters, 532, 116029. https://doi.org/10.1016/j.epsl.2019.116029 gürbüz, k. (1985): karaomerli-akkuyu-balcalı bolgesi (n.adana) tersiyer istifinin sedimanter jeolojik incelenmesi.– çukurova üniversitesi fen bilimleri enstitüsü, m.sc.thesis – in turkish, 77 p. hempton, m. (1985): structure and deformation history of the bitlis suture near lake hazar, se turkey.– geological society of america bulletin, 96. https://doi.org/10.1130/0016-7606 higgins, j.a., blättler, c.l., lundstrom, e.a., santiago-ramos, d.p., akhtar, a.a., crüger ahm, a.s., bialik, o., holmden, c., bradbury, h., murray, s.t. & swart, p.k. (2018): mineralogy, early marine diagenesis, and the chemistry of shallow-water carbonate sediments.– geochimica et cosmochimica acta, 220, 512–534. https://doi.org/10.1016/j.gca.2017.09.046 hodell, d.a. (1994): editorial: progress and paradox in strontium isotope stratigraphy.– palaeoceanography, 9, 395–398. https://doi.org/10.1029/ 94pa00291 hodell, d.a. & woodruff, f. (1994): miocene strontium isotope record of dsdp hole 30-289 – supplement to: hodell, d.a. & woodruff, f. (1994): variations in the strontium isotopic ratio of seawater during the miocene: stratigraphic and geochemical implications.– palaeoceanography, 9, 405–426. https://doi.org/10.1029/94pa00292 howarth, r. & mcarthur, j. (1997): statistics for strontium isotope stratigraphy: a robust lowess fit to the marine sr‐isotope curve for 0 to 206 ma, with look‐up table for derivation of numeric age.– the journal of geology, 105, 441–456. https://doi.org/10.1086/515938 ilgar, a., nemec, w., hakyemez, a. & karakuş, e. (2013): messinian forced regressions in the adana basin: a near-coincidence of tectonic and eustatic forcing.– turkish journal of earth sciences, 22/5, 864–889. https://doi.org/10.3906/yer-1208-3 jones, c.e. & jenkyns, h.c. (2001): seawater strontium isotopes, oceanic anoxic events, and seafloor hydrothermal activity in the jurassic and cretaceous.– american journal of science 301, 112–149. http://dx.doi. org/10.2475/ajs.301.2.112 kahle, h.g., cocard, m., peter, y., geiger, a., reilinger, r., barka, a. & veis, g. (2000): gps-derived strain rate field within the boundary zones of the eurasian, african, and arabian plates.– journal of geophysical research: solid earth, 105, 23353–23370. https://doi.org/10.1029/2000jb900238 kartveit, k.h., ulsund, h.b. & johansen, s.e. (2019): evidence of sea level drawdown at the end of the messinian salinity crisis and seismic investigation of the nahr menashe unit in the northern levant basin, offshore lebanon.– basin research, 31, 827–840. https://doi. org/10.1111/bre.12347 kaufman, a.j., jacobsen, s.b. & knoll, a.h. (1993): the vendian record of sr and c isotopic variations in seawater: implications for tectonics and palaeoclimate.– earth and planetary science letters, 120/3– 4, 409–430. https://doi.org/10.1016/0012-821x(93)90254-7 kelling, g., gökçen, s.l., floyd, p.a. & gökçen, n. (1987): neogene tectonics and plate convergence in the eastern mediterranean: new data from southern turkey.– geology, 15, 425–429. https://doi.org/10.1130/0091-7613(1987)15<425:ntapci>2.0.co;2 kocsis, l., vennemann, t.w., fontignie, d., baumgartner, c., montanari, a. & jelen, b. (2008): oceanographic and climatic evolution of the miocene mediterranean deduced from nd, sr, c, and o isotope compositions of marine fossils and sediments.– palaeoceanography, 23, pa4211. https://doi.org/10.1029/2007pa001540 koepnick, r.b., burke, w.h., denison, r.e., hetherington, e.a., nelson, h.f., otto, j.b. & waite, l.e. (1985): (appendix 1) biostratigraphy and sr isotopic composition of sediments from dsdp hole 17-167 (dataset). https://doi.org/10.1594/pangaea.706575 koepnick, r.b., denison, r. & dahl, d. (1988): the cenozoic seawater 87sr/86sr curve: data review and implications for correlation of marine strata.– palaeoceanography, 3, 743–756. http://dx.doi.org/10.1029/pa003i006p00743 köksal, s. (2019): the upper cretaceous intrusive rocks with extensive crustal contribution in hacımahmutuşağı area (aksaray/turkey).– geologica carpathica, 70, 261–276. http://dx.doi.org/10.2478/geoca-2019-0015 krijgsman, w., garcés, m., langereis, c., daams, r., dam, j., meulen, a.v.d., agustí, j. & cabrera, l. (1996): a new chronology for the middle to late miocene continental record in spain.– earth and planetary science letters, 142, 367–380. http://dx.doi.org/10.1016/0012-821x(96)00109-4 kuznetsov, a.b., gorokhov, i., semikhatov, m.a., melnikov, n.n. & kozlov, v.i. (1997): strontium isotopic composition from the inzer formation limestones, the upper riphean type section in southern urals.– transactions of the russian academy of sciences, earth science sections, 353, 319–324. kuznetsov, a.b., semikhatov, m.a., gorokhov, i.m., mel’nikov, n.n., konstantinove, g.v. & kutyavin, e.p. (2003): sr isotope composition in carbonates of the karatau group, southern urals, and standard curve of 87sr/86sr variations in the late riphean ocean.– stratigr. geological correlation, 11, 415–449. kuznetsov, a.b., semikhatov, m.a. & gorokhov, i.m. (2012): the sr isotope composition of the world ocean, marginal and inland seas: implications for the sr isotope stratigraphy.– stratigraphy and geological correlation, 20, 501–515, ht tps://doi.org/10.1134/ s0869593812060044 madof, a.s., bertoni, c. & lofi, j. (2019): discovery of vast fluvial deposits provides evidence for drawdown during the late miocene messinian salinity crisis.– geology, 47, 171–174. https://doi.org/10.1130/ g45873.1 mahmoud, y., masson, f., meghraoui, m., cakir, z., alchalbi, a., yavaşoglu, h., yönlü, o., daoud, m., ergintav, s. & i̇nan, s. (2013): kinematic study at the junction of the east anatolian fault and the dead sea fault from gps measurements.– journal of geodynamics, 67, 30–39. https://doi.org/10.1016/j.jog.2012.05.006 maillard, a., driussi, o., lofi, j., briais, a., chanier, f., huebscher, c. & gaullier, v. (2014): record of the messinian salinity crisis in the sw mallorca area (balearic promontory, spain).– marine geology, 357, 304–320. http://dx.doi.org/10.1016/j.margeo.2014.10.001 mcarthur, j.m. (1994): recent trends in strontium isotope stratigraphy.– terra nova, 6, 331-358. https://doi.org/10.1111/j.1365-3121.1994.tb00507.x g eologia c roatica 85akinci et al.: strontium isotopic stratigraphy of the miocene adana basin (s. anatolia) and its geological implications mcarthur, j.m., howarth, r.j. & bailey, t.r. (2001): strontium isotope stratigraphy: lowess version 3: best fit to the marine sr‐isotope curve for 0–509 ma and accompanying look‐up table for deriving numerical age.– the journal of geology, 109, 155–170. https://doi. org/10.1086/319243 mcarthur, j.m., howarth, r.j. & shields, g.a. (2012): strontium isotope stratigraphy.– in: gredstein f.m., ogg, j.g., schmotz, m.d. & ogg, g.m. (eds.): a geologic time scale, elsevier, amsterdam, 127–144. http://dx.doi.org/10.1016/b978-0-444-59425-9.00007-x micallef, a., camerlenghi, a., georgiopoulou, a., garcia-castellanos, d., gutscher, m.a., iacono, c., huvenne, v.a.i., mountjoy, j.j., paull, c.k., bas, t., spatola, d., facchin, l. & accettella, d. (2019): geomorphic evolution of the malta escarpment and implications for the messinian evaporative drawdown in the eastern mediterranean sea.– geomorphology, 327, 264–283. https://doi.org/10.1016/j.geomorph.2018.11.012 miller, k.g., feigenson, m.d., wright, j.d. & clement, b.m. (1991): miocene isotope reference section, deep sea drilling project site 608: an evaluation of isotope and biostratigraphic resolution.– palaeoceanography, 6, 33–52. https://doi.org/10.1029/90pa01941 nazik, a., & gürbüz, k. (1992): planktonic foraminiferal biostratigraphy of lower-middle miocene aged submarine fans in karaisalı-çatalan-eğner region (nw adana).– turkish geology bulletin, 35, 67–80. nazik, a. & toker, v. (1986): foraminiferal biostratigraphy of the middle miocene succession in the karaisalı region.– mineral research exploration journal, 103, 139-150. nurlu, n., türkmen, s., akinci, a.c. & şafak, ü. (2021): strontium isotope geochronology and geochemical provenance of a volcanoclastic sequence (salbaş member) in the adana basin (southern turkey).– arabian journal of geosciences, 14, 1634. https://doi.org/10.1007/s12517021-07624-z oslick, j.s., miller, k.g., feigenson, m.d. & wright, j.d. (1994): (table 1) age model of odp hole 120-747a (dataset). https://doi. org/10.1594/pangaea.52657 özalp, s. (1993): stratigraphy of the gülek-çamalan (tarsus) area.– yerbilimleri-geosound, 22, 73–84. özçelik, n. & yetiş, c. (1994): adana basin tertiary sequence planktic foraminiferal biostratigraphy of the güvenç formation.– yerbilimleri, 25, 21–30. perinçek, d. & çemen, i̇. (1990): the structural relationship between the east anatolian and dead sea fault-zones in se turkey.– tectonophysics, 172, 331–340. https://doi.org/10.1016/0040-1951(90)90039-b raad, f., lofi j., maillard, a., tzevahirtzian, a. & caruso, a. (2021): the messinian salinity crisis deposits in the balearic promontory: an undeformed analog of the msc sicilian basins?– marine and petroleum geology, 124, 104777. https://doi.org/10.1016/j.marpetgeo.2020.104777 reilinger, r., mcclusky, s., paradissis, d., ergintav, s. & vernant, p. (2010): geodetic constraints on the tectonic evolution of the aegean region and strain accumulation along the hellenic subduction zone.– tectonophysics, 488, 22–30. https://doi.org/10.1016/j.tecto.2009.05.027 robertson, a.h.f. (1998): mesozoic–tertiary tectonic evolution of the easternmost mediterranean area: integration of marine and land evidence.– in: robertson, a.h.f., emeis, k.c., richter, c. & camerlenghi, a. (eds): proceedings of the ocean drilling program: scientific results, 160, 723–782. robertson, a.h.f. & dixon, j.e. (1984): introduction: aspects of the geological evolution of the eastern mediterranean.– geological society london special publications, 17. https://doi.org/10.1144/gsl. sp.1984.017.01.02 scasso, r.a., mcarthur, j., del rio, c., martinez, s. & thirlwall, m. (2001): 87sr/86sr late miocene age of fossil molluscs in the ‘entrerriense’ of the valdés peninsula (chubut, argentina).– journal of south american earth sciences, 14, 319–329. schildgen, t.f., cosentino, d., frijia, g., castorina, f., dudas, f.ö., iadanza, a., sampalmieri, g., cipollari, p., caruso, a., bowring, s.a. & strecker, m.r. (2014): sea level and climate forcing of the sr isotope composition of late miocene mediterranean marine basins.– geochemistry geophysics geosystems, 15, 2964– 2983. https://doi.org/10.1002/2014gc005332 schmidt, g.c. (1961): stratigraphic nomenclature for the adana region petroleum district vii.– petroleum administration bull. ankara 6, 47–63. schneider, s., fürsich, f.t. & werner, w. (2009): sr-isotope stratigraphy of the upper jurassic of central portugal (lusitanian basin) based on oyster shells.– international journal of earth sciences, 98, 1949– 1970. http://dx.doi.org/10.1007/s00531-008-0359-3 semikhatov, m.a., gorokhov, i., kuznetsov, a.b., mel'niliv, n.n., podkovyrov, v. & kislova, i.v. (1998): sr isotopic composition in early late riphean sea water: limestones of the lakhanda group, the uhur-maya region, siberia.– doklady akademii nauk, 360, 236– 240. sinaci, m. (2010): nanoplankton biostratigraphy and environmental characteristics of miocene-pleistocene succession with drilling data in adana basin.– ankara university, phd thesis, 250 p. sirel, e. & gündüz, h. (1981): description of new borelis species from the hatay (s. of turkey) and elazig region (e. of turkey).– mineral research exploration institute turkey, 92, 70–74. stead, f.w. & stose, g.w. (1943): manganese and quartzite deposits in the lick mountain district, wythe county, virginia.– virginia geological survey bulletin, 59, 16 p. şafak, ü. & ünlügenç, u.c. (1992): ostracoda fauna and biostratigraphy of oligocene–lower miocene succession cropping out around kozoluk, solaklı and kevizli (n of adana) [kozoluk, solaki ve kevizli (ada­ na k’i) civarinda yüzeyleyen oligosen-orta miyosen yaşli istiflerin ostrakod faunasi ve biostratigrafisi – in turkish].– yerbilimleri (geosound), 21, 117–139. şafak, ü., akinci, a.c. & sonsun, h. (2021): ostracod fauna and palaeoenvironmental characteristics of the tuffite and memişli succession in the fadıl and salbaş region (adana/turkey).– journal of engineering sciences of adıyaman university, 8, 179–195. şengör, a.m.c. (1979): mid-mesozoic closure of permo–triassic tethys and its implications.– nature, 279, 590-593. http://dx.doi.org/10.1038/279590a0 şengör, a.m.c. & yilmaz, y. (1981): tethyan evolution of turkey: a plate tectonic approach.– tectonophysics, 75, 181–190. http://dx.doi. org/10.1016/0040-1951(81)90275-4 taraf, f., eren, m. & gürbüz, k. (2013): facies and microfacies features of the karaisalı formation (adana basin-türkiye).– geology bulletin of turkey, 56, 173–188. torres, n., och, l., hauser, p., furrer, g., brandl, h., vologina, e., sturm, m., bürgmann, h. & müller, b. (2014): early diagenetic processes generate iron and manganese oxide layers in the sediments of lake baikal, siberia.– journal of environmental monitoring, 16, 879–889. http://dx.doi.org/10.1039/c3em00676j ullmann, c.v., campbell, h.j., frei, r., hesselbo, pogge von strandmann, s.p. & korte, c. (2013): partial diagenetic overprint of late jurassic belemnites from new zealand: implications for the preservation potential of δ7li values in calcite fossils.– geochimica et cosmochimica acta, 120, 80–96. https://doi.org/10.1016/j. gca.2013.06.029 ünlügenç, u.c. (1986): the geology of the kızıldağ plateau (adana) area [kızıldağ yayla (adana) dolayının jeolojisi ç.ü. – in turkish].– fen bilimleri enstitüsü, msc. thesis, adana, 77 p. ünlügenç, u.c. (1993): controls on cenezoic sedimentation, adana basin southern turkey.– ph.d. thesis, university of keele, 228 p. ünlügenç, u.c. & akinci, a.c. (2020): sedimentary characteristics of early miocene platform deposits in the neogene adana basin, southern turkey.– turkish journal of earth sciences, 29, 629–648. http://dx.doi. org/10.3906/yer-1910-20 g eo lo gi a c ro at ic a 86 geologia croatica 78/1 ünlügenç, u.c. & demirkol, c. (1988): stratigraphy of the surroundings of kızıldağ yayla (adana) [kızıldağ yayla (adana) dolayının stra­ tigrafisi – in turkish].– jeoloji mühendisligi, 32, 17–25. ünlügenç, u.c. & şafak, ü. (1992): enviromental interpretation of the early miocene deposits (kaplankaya formation) in the adana basin, s. türkiye.– yerbilimleri, 20, 363. ünlügenç, u.c., akinci, a.c. & karakilçik, h. (2019): sedimentary evidences for the depositional and environmental changes regarding to regression during mid to late miocene in the neogene adana basin (southern turkey).– journal of engineering and architecture, 34, 1–8. http://dx.doi.org/10.21605/cukurovaummfd.702008 vasiliev, i., mezger, e.m., lugli, s., reichart, g.j., manzi, v. & roveri, m. (2017): how dry was the mediterranean during the messinian salinity crisis?– palaeogeography, palaeoclimatology, palaeoecology, 471, 120–133. https://doi.org/10.1016/j.palaeo.2017.01.032 veizer, j. (1983): trace elements and isotopes in sedimentary carbonates.– reviews in mineralogy and geochemistry, 11, 265–299. vescogni, a., bosellini, f.r., cipriani, a., gürler, g., ilgar, a. & paganelli, e. (2014): the dağpazarı carbonate platform (mut basin, southern turkey): facies and environmental reconstruction of a coral reef system during the middle miocene climatic optimum.– palaeogeography, palaeoclimatology, palaeoecology, 410, 213–232. http:// dx.doi.org/10.1016/j.palaeo.2014.05.040 wierzbowski, h. (2013): strontium isotope composition of sedimentary rocks and its application to chemostratigraphy and palaeoenvironmental reconstructions.– annales umcs, sectio aaa: physica, 68. http://doi. org/10.2478/v10246-012-0017-2 yalçin, m.n. & görür, n. (1984): sedimentological evolution of the adana basin.– in: tekeli, o. & göncüoğlu, m.c. (eds.): geology of the taurus belt: proceedings of international symposium, ankara, turkey, 26–29, 125–142. yang, s., jiang, s., ling, h., xia, x., sun, m. & wang, d. (2007): srnd isotopic compositions of the changjiang sediments: implications for tracing sediment sources.– science in china series d-earth sciences, 50, 1556–1565. https://doi.org/10.1007/s11430-007-0052-6 yetiş, c. (1988): reorganisation of the tertiary stratigraphy in the adana basin, southern turkey.– newsletter stratigraphy, 20, 43–58. yetiş, c. & demirkol, c. (1986): detailed study of the western part of the adana basin [adana baseni batı kesiminin detay etüdü – in turkish].– mta report, 8037, 187 p. (unpublished). yetiş, c., demirkol, c. & kerey, e. (1986): facies and environmental characteristics of the kuzgun formation (upper miocene) of the adana basin.– bulletin of the geological society of turkey, 29, 81–96. yilmaz, y. (1993): new evidence and model on the evolution of the southeast anatolian orogen.– geological society of america bulletin, 105, 251–271. https://doi.org/10.1130/0016-7606(1993)105<0251:neamot>2.3.co;2 2018 | 71/1 | 29–39 | 6 figs. | 5 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction over the last few decades advances in computing have created new opportunities for soil mapping, enabling the creation of more detailed soil maps at lower costs and in less time. the idea of digital soil mapping (dsm) is that existing soil information can be combined with auxiliary data using geoinformation and mathematical methods. by analyzing the relationship between soil and soil forming factors, outdated and less detailed soil maps can be improved. furthermore, with the help of prediction models information may be obtained on areas where soil data are limited or soil surveys have never been conducted. in the “scorpan” framework (mcbratney et al. 2003) seven important factors are defined and recommended for use in soil modelling and mapping: s=f(s,c,o,r,p,a,n) where: s=soil, c=climate, o=organism, r=relief, p=parent material, a=age and n=spatial position. auxiliary data are generally derived from thematic maps (relief, land cover, geology, and climate). these provide a wealth of data on environmental conditions, but in some cases it is difficult to extract useful information for dsm. this study focuses on geology, which is examined in detail less frequently as an aux the role of geology in the spatial prediction of soil properties in the watershed of lake balaton, hungary piroska kassai and istván sisák department of crop production and soil science, university of pannonia, georgikon faculty, deák ferenc u. 16., 8360 keszthely, hungary (kassai.piroska@georgikon.hu; sisak@georgikon.hu) doi: 10.4154/gc.2018.04 abstract there is no standard methodology which allows the incorporation of geological information into digital soil mapping (dsm) despite the great potential of geology as environmental covariate in dsm. to fill this gap, in this study, a geochemical parent material classification scheme was tested on the watershed area of lake balaton, for which soil maps at a finer scale have not yet been created. a parent material map was prepared on the basis of a 1:100 000 surface geology map in order to make the incorporation of soil modelling and mapping possible. legacy data of 12400 soil sample points was used in order to examine the role of geology in the quantitative distribution of some soil properties and element content (liquid limit, soil organic carbon, ph(kcl), caco3, mg, cu, zn, mn). results confirm that the sio2 content of the parent material influences the properties of the derived soils. in the second part of the study random forest models were developed for three major soil properties (liquid limit, soil organic carbon, ph) with the use of additional environmental covariates: elevation, slope, aspect, curvature, topographic position index (tpi), annual average temperature, annual average precipitation, remote sensing based normalized difference vegetation index (ndvi) and land cover information. the performance and accuracy of the models were evaluated on the basis of the coefficient of determination (r2) and root mean square error (rmse), calculated on a randomly selected validation dataset (20% of the database). the models performed with r2 values of 0.72, 0.6 and 0.68 for liquid limit, soil organic carbon and ph respectively. the importance of variables was also examined in the rf models, and this demonstrated that while geology is among the best-performing predictors, in neither case is it the most important variable. ninety metre resolution maps of the three major soil properties were compiled by making spatial predictions with the rf models developed here. for validation of the maps, an independent soil database was used, which showed that the prediction performed well on the cultivated area where the concordance correlation coefficients (ccc) were 0.73, 0.73 and 0.69 for liquid limit, ph and soil organic carbon respectively. iliary data layer, despite its importance in soil formation. jenny (1941) defined parent material as the initial state of the soil system which is the substratum of soil formation, and the physical and chemical properties of the underlying rocks are important factors in the process. this geological background as a passive factor affects the formation of the soil profile (stefanovits et al., 2005). generally, the most readily available source of parent material information can be found in surface geology maps. however, on the basis of comprehensive studies, geological maps are only used in less than a quarter of dsm projects (gray et al., 2016). this degree of neglect may generally be ascribed to the difficulty of interpretation of geological maps from a pedological point of view. geology is also commonly omitted from the analyses on account of its lack of explanatory power in soil modelling (beguin et al., 2017), though this may also be the result of the inappropriate use of geology as an environmental covariate; special expert knowledge is often required in order to convert the information contained in geological maps into meaningful soil covariates (behrens et al., 2005). the main problem is that the classification of the units on geology maps is generally based on the age and the genesis of rocks, while this information is irrelevant in dsm. in addition, article history: manuscript received january 05, 2018 revised manuscript accepted february 19, 2018 available online february 28, 2018 keywords: parent material classification, soil properties, spatial prediction, digital soil mapping, lake balaton g eo lo gi a c ro at ic a geologia croatica 71/130 usually too many units are distinguished on a geology map, making it difficult to explore the relationship between the geology and the derived soils. to alleviate this problem, geological units are usually reclassified based on rock type. in the fao system there is a detailed classification scheme which allows the easy conversion of the units used in geological maps into parent material (pm) categories (fao, 2006). however, this four-level classification places too great an emhasis on the genesis of rocks. besides this, several important rock types are missing, and it is thus not well suited to the creation of pm categories. other pm classification schemes have also been developed which are more suitable for the purposes of dsm. soter is a harmonization and a mapping method combining landform classes and pm categories to define terrain units, which are then in turn represented by typical soils. based on the results of the esoter project a new pm classification has been developed which is the revision of the previous fao scheme but it has a pedologically relevant structure (van engelen & dijkshoorn, 2013). the basis of this five-level classification system is the geochemical character of rocks, and the classes are clearly distinguished, being reflected in the various derivative soils. undoubtedly the most important feature of any parent material is its geochemical character. the basic concept of this approach is that the sio2 content is one of the most important features in rock classification, and especially in igneous rocks, which are classified into ultrabasic, basic, intermediate and acid groups based on the percentage of sio2 in their geochemical composition. gray et al. (2016) developed a reclassification method for all the rock types, including sedimentary and metamorphic rocks, based on their sio2 content, and this method has proven to be very effective in modelling and mapping soil properties. they demonstrated that certain important soil properties (soil organic carbon, ph, cation exchange capacity, sum of bases, total p and clay %) stand in clear relationship to sio2 content. this relationship allows the use of geological information in a semi-quantitative form through the application of a ‘silica index’which can be determined based on the median of the measured sio2 values in the new geological categories. the index works in the following way: in a parent material, high sio2 content generally means higher quartz content; this in turn has an inverse relationship with the clay and base cation content of the derivative soils. as soil texture is determined by the mineral fractions present in the soil (relative proportions of sand, silt and clay), it is obvious that the sio2 content of the parent material also plays a key role in soil physical properties. despite the effectiveness of gray’s method, it does have several shortcomings. any individual geochemical pm classification requires a great quantity of x-ray fluorescence (xrf) test data, in most cases not available locally, while the use of geochemical data measured elsewhere could distort the results. a typical case is that of loess, in which significant differences occur in sio2 content in different regions of the world (újvári et al. 2008). regional averages of the sio2 content of these sedimentary rocks range from 60% to 80%; they cannot, therefore, be assigned to a single category, due to the high degree of diversity in their geochemical composition. sedimentary rocks are generally problematic in this regard, and as a result, a unified geochemical pm classification scheme cannot be developed, so this approach cannot be standardized. nevertheless, in cases where locally measured geochemical data are available, this method seems to be the most suitable for pedological purposes. despite the fact that dsm methods have already been widely used and recognition of the importance of geology is on the increase, only limited information is available concerning the proper use of geology as an auxiliary data source, and also about its role in the prediction of soil properties. one task is to resolve the contradictory nature of our understanding of geology as an environmental covariate: in some studies it is considered the strongest (gray et al. 2016) or one of the strongest (vaysse & lagacherie, 2016, xiong et al. 2014, wiesmeier, 2011) pre dictors in dsm, while in most cases it cannot be used effectively. since a surface geology map is available for hungary (gyalog & síkhegyi, 2005), and it is detailed enough for dsm purposes, the decision was made to examine the role of geology in the spatial distribution of soil properties. in this study the aim was to compile a parent material map on the basis of the surface geology map using gray’s geochemical approach, then to use it in our dsm project. models based on geology and other environmental covariates were developed for three selected soil properties liquid limit, ph and soil organic carbon which are important features of the soils and are also important factors in soil classification. based on the developed models, predictions were made for our whole study area. one important purpose of this study is to evaluate the role of geology in soil modelling and mapping, but a further aim was to compile fine resolution maps of the three selected soil properties for the watershed area of lake balaton in order to serve the increasing need for more detailed soil data for environmental impact assesment in this area. 2. matherials and methods 2.1. study area the watershed area of lake balaton (the largest freshwater lake in central europe) is located between longitude 16°17’43’’e and 18°11’26’’e and latitude 47°6’47’’n and 46°17’32’’n (fig. 1). fine scale soil maps of the whole watershed have not yet been created, although detailed legacy soil information is available. for environmental reasons (especially for water quality protection) it is particularly important to create detailed soil maps, as a large part of the watershed lies on cultivated land. detailed soil maps could support the more accurate assessment of diffuse phosphorus loads, and also aid in the targeting of erosion and runoff control measures. from a geological point of view, the watershed can be divided into two parts. the balaton highland is located to the north of the lake, where older (palaeozoic-mesozoic), mainly carbonate rocks dominate, but basalt, sandstone, and methamorhic rocks are also present in notable quantities. this elevated area together with the keszthely hills at the southwestern end of lake balaton represents the southern part of the transdanubian central range. the other part of the watershed is located south and west of the lake (somogy and zala river subwatershed), lies at a lower altitude, and is mainly covered by younger (neogene and quaternary) alluvial and aeolian sediments. from a pedological point of view the watershed also shows a great diversity. the following world reference base (wrb) units can be distinguished in the area: rendzic leptosols dominate the upland area, with haplic luvisols on the foothills, in the valleys and on the deeply weathered basalt plateaus. in the lower areas, the dominant soils are haplic luvisols, coloured with eutric cambisols in drier regions, stagnic luvisols in the western areas with high precipitation, lamellic and dystric arenosols in g eologia c roatica kassai and sisák: the role of geology in the spatial prediction of soil properties in the watershed of lake balaton, hungary 31 the southern part, sapric histosols near to the lake in former bays, and in general, gleysols and fluvisols in the valleys. soil erosion by water is prevalent in certain regions with high relief. the climate of this area is a typical european continental climate, with warm summers and fairly cold winters. the annual precipitation is about 400-600 mm. 2.2. the 1:100 000 scale surface geology map and the derived parent material map the hungarian geology institute published a 1:100 000 scale digital surface geology map, the result of more than ten years of harmonisation and updating, in 2005 (gyalog&síkhegyi, 2005). in lowland areas, 1:100 000 scale geological mapping had been completed in the course of the preceding 10-30 years. however, in hilly areas, finer scale legacy maps (e.g. 1: 10 000, 1:25 000 and 1:50 000) formed the basis of this new map. this is the reason why it appears far more detailed and accurate than soil maps with the same nominal scale (e.g. agrotopo, 1:100 000, 1994), especially in those hilly areas for which limited soil information is available. the 1:100 000 scale surface geology map shows the presence of 143 geological units in the watershed of lake balaton: 3 palaeozoic, 42 mesozoic, 3 palaeogene, 24 neogene, and 71 quaternary formations with more than 20 rock types. we classified these units into broad categories based on their approximate sio2 content. the basis of this new classification was the scheme developed by gray et al. (2016), modified to take into account the fact that different rock types dominate in the watershed than in the australian study area. the first step was the selection of some characteristic rocks and sediment types common in our study area. these were the following: aeolian sand, aeolian loess, fluvial sediments of varying grain size, sandstone, limestone, dolomite, marl, basalt, and sesquioxides. the average sio2 content of these rocks was determined, and the framework of a broad geochemical classification constructed. an attempt was made to place each geological formation into one or other of the new geological categories based on sio2 content. in several cases, legacy x-ray fluorescence (xrf) data were available (budai&csillag, 1999; újvári et al. 2008; bohn, 1979; juhász, 1962; gyalog&horváth, 2004; embey-isztin et al. 1993), but data measured in our study area cannot be then simply assigned to all rock types. in such cases, research was conducted for legacy data of similar rocks from all over the world. to estimate the approximate sio2 content of the various rocks the free georoc database (sarbas&nohl, 2008) was employed, with additional legacy xrf data (pettijohn 1963; clarke 1920; gu et al., 2013). our final classification structure contains nine groups, based on approximate sio2 content (table 1). each original geological formation was assigned to one of these groups. in some cases this classification was difficult, especially where a combination of rock types or sediments were present. on the basis of the method employed by gray et al. (2016), in these cases an overall single class was determined; though this was actually an average of several classes. sesquioxides and carbonate rocks were not excluded from our sio2 content based classification scheme, even though these classes have a low sio2 content. a property other than sio2 content had to be taken into consideration in the last group, because organic material has a strong effect on derivative soils. for this reason, a separate group was created for those sediments with the highest organic matter content. the parent material map compiled from these nine groups can be seen in fig. 2. 2.3. other environmental covariates the basis of dsm is the empirical quantitative description of soil formation as a function of climate, organism, relief (topography), parent material, age and spatial position. in order to build predictive soil models, detailed information concerning these soil table 1. broad geochemical classification of rocks and sediments. geological classes approximate sio2 % rock types 1 80–90% aeolian sand, quartzite 2 70–80% alluvial sand, gravel, proluvial and deluvial sand, sandstone, loessy sand 3 65–70% loess, sandy loess 4 60–65% aleurite (alluvial, limnic, slope, deluvial) 5 50–60% clay (alluvial, limnic, slope, deluvial) 6 45–50% basalt 7 20–30% bauxite, bauxitic clay, clayey bauxite, 8 1–10% limestone, dolomite, marl 9 – organic (peat) figure 1. location of the watershed of lake balaton in europe (left) and the elevation of the area (right) based on the 90 m resolution digital elevation model (nasa, srtm). g eo lo gi a c ro at ic a geologia croatica 71/132 forming factors is required. besides geology, a different set of climate, topography, vegetation and land cover covariates was used. these are summarized in table 2. the geoinformatical processing of the environmental covariates was carried out in arcgis 10.0.0. 2.3.1. topograpy: a digital elevation model (srtm dem) at a resolution of 90 m was used in the analysis (jarvis et al. 2008). slope, aspect, and curvature were derived from the dem, and the topographic position index (tpi) was also calculated for each cell following the method developed by weiss (2001) and jenness (2016). a circle of 2000 m radius was used to determine the topographic position, which is an index for the quantitative description of geomorphology. the five topographic factors (elevation, slope, curvature, aspect, tpi) were used as quantitative variables in the description of relief. 2.3.2. climate: averaged annual precipitation and temperature data selected from the free worldclim bioclimatic variables (fick&hijmans, 2017) were used in the analysis. these rasters have a resolution of approximately 750 m. 2.3.3. land cover: corine land cover categories produced by the european environment agency (2013) based on satellite images from the land surface were used. in our study area, 22 of the original 44 corine categories appear. this land cover database provides concurrent information on both land use and vegetation. 2.3.4. vegetation: the normalized difference vegetation index (ndvi), derived from modis (nasa) satellite data at a resolution of 250 m (for the month of june 2016) was used in the analysis (mod13q1). table 2. description of environmental covariates. predictor variable source resolution type range elevation nasa srtm dem 90 m q 104.8–592.6 m slope nasa srtm dem 90 m q 0–61.8° curvature nasa srtm dem 90 m q –8.8–5.4 aspect nasa srtm dem 90 m q 0–360° tpi nasa srtm dem 90 m q –5.3–13.6 annual precipitation worldclim database 750 m q 544–776 mm annual temperature worldclim database 750 m q 8.6–10.9 °c land cover european environment agency, corine 1:100 000 c 1–22 geology geological and geophysical insitute of hungary 1:100 000 c 1–9 ndvi nasa modis satellite 13q1, 09-jun-2016 250 m q 1564–9296 q: quantitative, c: categorical figure 2. parent material map of the watershed area of lake balaton. the categories (1-8) are in descending order based on the approximate sio2 content (see  table 1). g eologia c roatica kassai and sisák: the role of geology in the spatial prediction of soil properties in the watershed of lake balaton, hungary 33 2.4. soil dataset soil data (12400 points) from the national pedological and crop production database (npcpd) collected between 1985-1989 were used in the analysis. the nationwide soil property map series for agricultural areas in hungary had also been previously created based mainly on this database (tóth et al. 2015). it contains liquid limit (ka) according to arany (1943), humus, ph, caco3, mg, n, p, k, cu, zn, mn values measured in the upper 25 centimetres of the soil. the detailed description of the database including the methodology of the soil tests were presented previously by kocsis et al. (2014). here only the three mapped soil properties are discussed in detail. organic carbon content was measured after wet combustion with kalium-bichromate sulfuric acid solution by the titration method and then humus content was calculated. before the modelling and mapping processes were carried out, humus was converted back to soil organic carbon content (soc) by dividing by 1.724 because soc is more stable than humus and more comparative data are available about this parameter. the ph was measured in either distilled water or 1 m kcl solution in 1:2.5 soil to solution ratio supension after thorough wetting and two hours shaking. the ‘ka’ stands for liquid limit according to arany (1943). it refers to the quantity of water (cm³) necessary for the creation of a fully water saturated “aggregate free” soil paste from a 100 g oven-dry soil sample to reach the “endpoint indicator”, the “sticky point” (várallyay, 2013). ka was simplified from the traditional liquid limit determination (casagrande, 1932) for agricultural purposes. liquid limit can be considered a good proxy for a particle size distribution test. it ranges from sandy (ka=~25-30) to clayey soils (ka>50). the major advantage of this measure is its simplicity and time-efficiency. some elements of the npcpd database (plant available p, k, and n) were ignored in our analysis, as they may have been strongly influenced by temporarily and temporally variable effects such as those from fertilization. the soil information derived from the npcpd database is summarized in table 3. since the npcpd represents mainly cultivated land, additional data were required, and especially those concerning forested areas. fifty forest points were selected from the land evaluation database maintained by the land registery offices in hungary. they record the exact geographical positions and soil profile descriptions of reference sites, which are then used to judge the relative primary production value of all plots of productive land. table 3. summary of the npcpd soil data. soil property ka soc ph(kcl) caco3 mg zn cu mn dimension cm3 % – % ppm ppm ppm ppm range 24–81 0.30–3.19 3.52–7.76 0–20 10–440 0,4–11.8 0–13.2 2.1–132 figure 3. spatial distribution of the soil sample points and the validation points. g eo lo gi a c ro at ic a geologia croatica 71/134 the final soil property maps were validated based on the topsoil data from the soil conservation information and monitoring system (sims), which is independent of the npcpd, similar methods were, however, used in measurement of the soil properties (várallyay et al., 2010). sims consists of 1,236 soil profile descriptions nationwide with highly detailed physical and chemical test data. sixty eight points fall within the watershed, and from these the humus, ph and liquid limit data were used (fig. 3). 2.5 spatial prediction of soil properties using the random forest algorithm firstly a correlation matrix was calculated in order to identify the highly correlated variables and avoid the distortion effect of redundant features in our analysis. for the modelling of major soil properties (liquid limit, ph, soil organic carbon) the random forest algorithm was used. the use of this method, developed by breiman (2001), is very widespread in environment modelling because it has lots of benefits. it can also be used for classification and regression tasks, and there are no restrictions on the types of variables. the random forest model consists of a number of decision trees from which a predefined number of randomly selected independent variables (different subsamples of the data) are used. the final result is derived from the mean predictions made on the basis of individual trees. in this study the soil properties are dependent variables and the environment covariates are independent (predictor) variables. for each soil property, an individual model was constructed using the predictors. in the analysis, 80% of observations were randomly selected and used for rf modeling and the other 20% for model validation. for each model, the optimum number of randomly selected independent variables was determined. the recursive feature elimination (rfe) method was applied in feature selection in order to identify the most relevant predictors; in the final models only these variables were used. rfe algorithm ranks the variables by its importance and automatically selects a subset of the most predictive features (kuhn, 2008). the coefficient of determination (r2), defined by the percentage of variation explained by the model, was employed to evaluate prediction performance, and rmse (root mean square error) to measure the accuracy of the models. for the analyses the ‘random forest’ (liaw&wiener, 2002) and the ‘caret’ (kuhn, 2008) package were used in the r environment (r core team, 2017). 2.6. evaluation of the role of geology in the spatial distribution of soil properties the effect of geology was analyzed independently of other environment covariates, and its importance in the soil property models was also evaluated. since accurate geochemical data are not available for all geological formations, it was decided not to use the ‘silica index’ (gray et al., 2016), but instead use broad categories based on the approximate sio2 content of the various rocks. for this reason, analyses of variance (anova) in which the nine geological classes are factors and accurate values for sio2 content are not required were carried out in order to examine the effect of geology on soil properties. the other approach to the evaluation of the role of geology was the measurement of variable importance in the soil property models in which a comparison with other environment covariates was also possible. 3. results 3.1. correlation analysis of the predictor varaiables the correlation matrix (table 4.) of the numerical predictor variables showed that in the dataset used here the variables are not highly correlated (maximum absolute correlation is 0.67, but values are generally lower than 0.4). 3.2. model performance and accuracy the results show that in the rf models the environmental predictor variables explain 69.65%, 57.78% and 65.31% of the variation of the liquid limit, soc, and ph, respectively if all independent variables are used. in order to construct models with a higher degree of accuracy and better performance, the rfe method was employed. after removing non-relevant variables based on the results of rfe, the performance of these models increased to 72.4%, 60.3% and 68.4%. aspect, curvature and ndvi were ignored in all three models, as was slope in the case of liquid limit and ph. the final models were constructed from 500 regression trees using 4 randomly selected variables from the relevant predictors. the observed rmse values of the validation samples were 5.29 for the liquid limit, 0.27 for soc and 0.54 for ph in the final models. 3.3. the effect of geology on soil properties and its importance in rf models one of the most important goals of the analysis was to evaluate the role of geology in the spatial distribuiton of soil properties. firstly, the effect of geology was analyzed independently of other environment covariates using the anova method. significant differences were found in geological classes in the case of all the soil properties of the npcpd. tukey post hoc tests show which groups may genuinely be distinguished from each other (table 5.) although not all classes differ significnatly, the means show an interesting trend, namely, that almost all soil properties in the npcpd show an inverse relationship with the approximate sio2 table 4. correlation matrix of the numerical predictor variable. aspect curvature precipitation elevation slope temperature tpi ndvi aspect 1 0 0.05 0.07 0.09 –0.03 0.02 –0.04 curvature 1 0.04 0.08 004 –0.03 0.16 0.01 precipitation 1 0.29 0.05 –0.54 0.19 –0.05 elevation 1 0.3 –0.67 0.38 –0.07 slope 1 –0.23 0.09 0.06 temperature 1 –0.12 0.08 tpi 1 –0.07 ndvi 1 g eologia c roatica kassai and sisák: the role of geology in the spatial prediction of soil properties in the watershed of lake balaton, hungary 35 content. consequently, this pm classification provides relevant information for pedological purposes, and it may be expected to be well suited for use in the modelling and mapping of soil properties. the actual importance of geology in the major soil property models was evaluated based on the results of the rfe and variable importance plots of the rf models. the rfe method showed that geology is a relevant predictor in the case of all three major soil properties. variable importance plots ranked the independent variables based on the increase of mse and node purity in the rf models after removing the variables (prasad et al., 2006). this method enables the examination of the importance of geology in comparison to the other variables. the results of these may be seen in fig. 4. the best performing predictors can be seen on the top of the plots. judging by the importance of the variables, geology is among the top predictors, but unlike its position in gray’s results, it is not the most important variable in any case. 3.4. major soil property maps compiled using the rf models in order to compile soil property maps rasters were created at a resolution of 90 m, and predictions for each cell were made using the developed rf models. the ’raster’ r package (hijmans, 2016) was used in the creation of the final maps. the results of these are three soil property maps for the watershed of lake balaton (fig. 5), which are at present the most detailed soil maps of the area. table 5. the results of the tukey post hoc tests. geology classes liquid limit (cm3) soc (%) ph (kcl) caco3 (%) mg (ppm) zn (ppm) cu (ppm) mn (ppm) 1 28.31a 0.75a 5.14a 0.20a 91.95a 1.49a 1.95a 103.36b,c 2 34.89b 0.89a,b 5.81b 0.73a,b 134.20b 1.96a,b 2.71a,b 89.12a,b,c 3 38.60b,c 0.92a,b 5.81b 0.53a,b 176.44c 1.72a 2.77a,b 97.84a,b,c 4 42.12c,d 1.08b 6.15b,c 1.24b,c,d 197.18c 2.07a,b 2.87b,c 77.88a,b 5 44.03d,e 1.35c 6.16b,c 1.66b,c,d 199.95c 2.43b,c 2.86b,c 73.38a 6 44.40d,e 1,10b 6.17b,c 2.13d,e 245.33d 2.51b,c 3.27b,c 98.28a,b,c 7 45.80d,e 1,42c 6.55c,d 1.92c,d,e 269.51d 2.64c 3.71c 108.06c 8 47.81e 1.41c 6.69d 3.01e 260.78 d 2.53b,c 3.71c 82.09a,b 9 (organic) 46.71e 1.38c 6.48c,d 1.69c,d 185.71c 2.09b,c 3.27b,c 80.76a,b a,b,c,d,e: the means with the same letter are not significantly different (p-value < 0.05). figure 4. variable importance plots of the rf models based on the precentage increase of mse and node purity. g eo lo gi a c ro at ic a geologia croatica 71/136 3.5. validation of the maps for the validation of the maps, data of 64 soil sample points from the soil conservation information and monitoring system (sims) were used. lin’s concordance was employed to compare predicted and observed values. the concordance correlation coefficients (ccc) were 0.55, 0.59 and 0.50 for liquid limit, ph and soc, respectively. but if points were selected only from cultivated areas, the ccc values increased to 0.73, 0.73 and 0.69 (fig. 6.). the main reason seems to be that the dataset forming the base of our soil property models contains data primarly from cultivated land, and thus it is in such locations the prediction models perform better. 4. discussion in the present study, digital maps of three major soil properties, liquid limit, ph and soil organic carbon (soc) were created for the watershed area of lake balaton based on legacy soil information using the random forest algorithm. while different sets of environmental covariates were employed in the prediction, particular attention was paid to the role of geology. a parent material map was prepared through the application of a geochemical approach, with the reclassification of the original map units from the 1:100 000 surface geology map. it was confirmed that sio2 content based pm categories are capable of providing relevant information for soil prediction. nonetheless, a great deal of xrf data are required in order to arrive at the correct classification, and it is precisely this which is the main drawback to the method proposed by gray et al. (2016). in the case of the classification constructed here, this type of inaccuracy may also distort the final results. this, in turn, may well be one of the reasons why in the derived rf models geology is not the strongest predictor, in contrast to the conclusions arrived at by gray et al. (2016). the other possible explanation for this is the scale dependency of the importance of geology, i.e. the study area in the present paper is not large enough, and is less diverse from a geological point of view. another factor is that the spatial distribution of the soil sample points can weaken the result, as the soil database used covers mainly cultivated land where the geology is less diverse. although the database was broadened with additional points on forest land, this was not sufficient to eliminate the imbalance in distribution of the sample points; it is possible that this also reduced the importance of geology in the models developed. scale dependency and the imbalance in the spatial distribution of the sampling points may well have led to a result in which geology is not the most important predictor, but this assumption cannot be verified due to a lack of comparative data. although a similar geochemical pm classification scheme has yet to be used in other studies, it is remarkable that in general, geology is not the most important predictor in dsm projects. unfortunately, geology is not often examined in detail as a predictor variable in dsm, and thus only a few data are available with which it would be possible to compare the results arrived at here. usually, different variables dominate in each model, depending on the target variables. this is a realistic consequence, since soil formation is the function of several environmental factors. figure 5. spatial prediction of major soil properties. g eologia c roatica kassai and sisák: the role of geology in the spatial prediction of soil properties in the watershed of lake balaton, hungary 37 according to vaysse & lagacherie (2014), the prediction of soc is driven primarily by climate co-variables. araujo et al. (2017) also demonstrated in a recent study that the effect of climate on soc can be stronger than the parent material driven textural and mineralogical control of soc retention because the soil organic matter decomposition rate is strongly dependent on climatic conditions (e.g. in a relatively cool environment the stabilization of soil organic matter is more efficient). besides climatic variables, remote sensing vegetation indices (ndvi, evi) and land use information may also have greater predictive value in soc models (dharumarajan et al., 2017). only silva et al. (2016) found that parent material plays a decisive role in determining soil characteristics and that geology has a stronger effect on soc than climate under humid-semi-arid conditions. although wiesmeier at al. (2011) also reported a high value for the predictive role of geology in modelling soil organic matter, it should be mentioned that they do not use any climatic variables, and that even then, land use was a stronger predictor than geology in their model. the results of the present study confirm that both geology and climate, and especially annual precipitation, have a strong effect on soc, but land use and vegetation data (land cover) are also important factors. in the case of ph, we arrived at similar conclusions. some studies have reported that geology has the strongest influence on the ph of the derived soils (e.g. vaysse & lagacherie 2014), but climatic factors are also important, and elevation is often a key factor (dharumarajan et al., 2017), similar to the ph model in this paper. liquid limit comparative data are not available for the evaluation of the role of geology in soil because this physical property is in general used only in hungary. since liquid limit is related to soil texture, it is obvious that this property also stands in close relation to climate and geology, as it is essentially these two factors which determine weathering processes. similar results were reported by rodríguez-lado & lado (2017) about the scaling properties of particle size distributions where parent material and climatic indices are the most influential variables. in our liquid limit model, climate is a stronger factor than geology, as was also the case in the ph and soc models. summarizing the results, the importance of geology in soil prediction has been definitely established, and sio2 content based pm classification may be considered suitable for dsm purposes, despite the fact that geology turned out not to be the most important variable. nevetheless, it is also important to note that, although our study area was relatively small in geographical extent, climatic variables (especially annual precipitation) still have the strongest influence on soil properties. the explanation for this may be the young age of the sediments covering the greater part of the watershed, as these are less weathered and landscape formation is still in its initial phase, with the presence of intensive weathering processes. the relatively small effect in the studied area of certain topographical variables (aspect, curvature, slope) on soil properties is also interesting, although other authors have reported similar results (camera et al. 2017, dharumarajan et al. 2017, wiesmeier et al. 2011). figure 6. concordance correlation plots for liquid limit (cm3), ph and soc (%). g eo lo gi a c ro at ic a geologia croatica 71/138 the most important results of the present study are the three final soil property maps, which are the most detailed soil maps for the watershed area of lake balaton currently in existence and is to be hoped that they can be used in future assessments. finally, an important outcome of the validation of the maps is that the spatial distribution of the existing soil sample points can and does result in great differences in the degree of uncertainty of the predicted maps in different regions. this is one of the main disadvantages of the use of legacy data, and it indicates the need for new soil surveys in the area. the validation results showed that our predictions were more accurate on cultivated land, from which most of the soil data originated. this is in line with previous work (tóth et al., 2015), in which this database was used for nationwide soil modelling and mapping and the predictions proved to be reliable only on cultivated land. however, based on these results the areas from which additional soil samples should be taken can easily be delineated and this, in turn, would improve any future maps. 5. conclusion the method of digital soil mapping developed in the last few decades is one of the most important innovations in soil science. however, the effective use of dsm requires lots of information about the role of soil forming factors including parent material. in this study a geochemical approach developed by gray et al (2016) was applied in order to convert geology to a usable soil covariate. a legacy database (npcpd) with 12400 soil test data and the 1:100 000 scaled surface geology map of hungary facilitated the performance of a comprehensive analysis of the relationship between geology and soils and evaluation the role of geology in soil modelling and mapping. well performing predictive models could be built using geology and further environmental covariates (climate, topography, land cover) for three major soil properties (liquid limit, soil organic carbon, ph) in our study area. based on the results, it has been confirmed that the geochemical classification of the rocks is useful for dsm purposes, but accurate geochemical data would be essential to improve this method. nevertheless it should be mentioned that the potential use of more accurate geochemical data does not necessarily result in determining that geology acts as the most influental variable in soil prediction because additional factors are also involved including scale dependency, other soil forming factors, spatial distribution of the soil data. in our study area it seems that climate (especially annual precipitation) has a greater impact on soil properties than geology. by using the developed models, predictions were made which resulted in the most detailed soil maps available at present for the watershed of lake balaton. however, map validation showed that the uncertainty is much higher in the areas (forests and hilly areas) where limited soil data is available but a new soil survey in these areas could improve both the models and the predictions. acknowledgement we acknowledge the financial support of széchenyi 2020 under the efop-3.6.1-16-2016-00015. references agrotopo (1994): agrotopo database. spatial soil information system. rissac has. budapest. https://maps.rissac.hu:3344/webappbuilder/apps/2/ arany, s. (1943) a talajok rögszerkezete [the aggregate structure of soils-in hungarian].– mezőgazdasági kutatások, xvi., 220–249. araujo, m. a., zinn, y. l. & lal, r. (2017): soil parent material, texture and oxide contents have little effect on soil organic carbon retention in tropical highlands.– geoderma, 300, 1–10. doi: 10.1016/j.geoderma.2017.04.006 baranyai f., fekete, a. & kovács, i. (1987): a magyarországi talajtápanyagvizsgálatok eredményei [results of the soil nutrient assesment in hungary – in hungarian].– mezőgazdasági kiadó, budapest, 189 p. beguin, j., fuglstad, g.a., mansuy, n. & paré, d. (2017): predicting soil properties in the canadian boreal forest with limited data: comparison of spatial and non-spatial statistical approaches.– geoderma, 306, 195–205. doi: 10.1016/j. geoderma.2017.06.016 behrens, t., förster, h., scholten, t., steinrücken, u., spies, e.d. & goldschmitt, m. (2005): digital soil mapping using artificial neural networks. – journal of plant nutrition and soil science, 168, 1–13. doi: 10.1002/jpln. 200421414 budai, t. & csillag, g. (eds.): (1999): a balaton-felvidék földtana [geology of the balaton highland – in hungarian].– magyar állami földtani intézet, budapest, 257 p. bohn, p. (1979): a keszthelyi-hegység regionális földtana [geology of the keszthely hills – in hungarian].– geologica hungarica. series geologica 19, 197 p. breiman, l. (2001): random forests.– machine learning, 45/1, 5–32. doi: 10.1023/ a:1010933404324 casagrande, a. 1932. research on the atterberg limits of soils.– public roads, 13/8, 121–136. camera, c., zomeni, z, noller, j.s., zissimos, a.m., christoforou, i.c. & bruggeman, a. (2017): a high resolution map of soil types and physical properties for cyprus: a digital soil mapping optimization.– geoderma, 285, 35–49. doi: 10.1016/j.geoderma.2016.09.019 clarke, f.w. (1920) the data of geochemistry.– bulletin of the u.s. geological survey. washington, 832 p. dharumarajan, s., hegde, r. & singh, s.k. (2017): spatial prediction of major soil properties using random forest techniques a case study in semi-arid tropics of south india.– geoderma regional, 10, 154–162. doi: 10.1016/j.geodrs.2017.07.005 embey-isztin, a., dobosi, g., james, d., downes, h., poultidis, c. & scharbert, h.g. (1993): a compilation of new major, trace element and isotope geochemical analyses of the young alkali basalts from the pannonian basin.– fragmenta mineralogica and palaeontologica, 16, 5–26. european environment agency (2013): corine land cover (clc) 2006, version 17, kopenhagen k, denmark. crc/tr32 database (tr32db). fao (2006): guidelines for soil descriptions. 4th edition. food and agriculture organization of the united nations. rome, 77 p. fick, s.e. & hijmans, r.j. (2017): worldclim 2: new 1-km spatial resolution climate surfaces for global land areas.– international journal of climatology. doi: 10.1002/ joc.5086 gyalog, l. & síkhegyi, f. (eds.)(2005): magyarország földtani térképe, m=1:100 000. [the geological map of hungary, 1:100 000 – in hungarian].– magyar állami földtani intézet kiadványa. budapest. gyalog, l. & horváth, i. (2004): a velencei-hegység és a balatonfő földtana [geology of the velence hills and the balatonfő – in hungarian].– magyar állami földtani intézet, budapest, 316 p. gray, j.m., bishop, t.f.a. & wilford, j.r. (2016): lithology and soil relationships for soil modelling and mapping.– catena, 147, 429–440. doi: 10.1016/j.catena.2016.07.045 gu, j., huang, z., fan, h., jin, z., yan, z. & zhang, j. (2013): mineralogy, geochemistry, and genesis of lateritic bauxite deposits in the wuchuan–zheng’an– daozhen area, northern guizhou province, china.– journal of geochemical exploration, 130, 44–59. doi: 10.1016/j.gexplo.2013.03.003 hijmans, r.j. (2016): raster: geographic data analysis and modeling. r package version 2.5-8. https://cran.r-project.org/package=raster jarvis, a., reuter, h.i., nelson, a. & guevara, e. (2008): hole-filled srtm for the globe version 4, available from the cgiar-csi srtm 90m database (http://srtm.csi.cgiar.org). jenness, j. (2006): topographic position index extension for arcview 3.x,v.1.3a. jenness enterprises. [online: www.jennessent.com/arcview/tpi.htm] jenny, h. (1941): factors of soil formation.– mcgray-hill book company, new york, 281 p. juhász, á. (1962): a balatonfelvidéki permi homokkőösszlet kvarcporfiranyagának eredete [the origin of the quartz porphyry material in the permian sandstones of balaton highland – in hungarian].– földtani közlöny, 92/2, 160–173. kocsis, m., tóth, g., berényi üveges, j. & makó, a. (2014): az agrokémiai irányítási és információs rendszer (aiir) adatbázis talajtani adatainak bemutatása és térbeli reprezentativitás-vizsgálata [presentation of soil data from the national pedological and crop production database and investigations on spatial representativeness – in hungarian].– agrokémia és talajtan, 63, 223–248. kuhn, m. (2008): building predictive models in r using the caret package.– journal of statistical software, 28/5, 1–26. doi: 10.18637/jss.v028.i05 g eologia c roatica kassai and sisák: the role of geology in the spatial prediction of soil properties in the watershed of lake balaton, hungary 39 liaw, a. & wiener, m. (2002). classification and regression by random forest.– r news 2/3, 18–22. mcbratney, a.b., mendonca santos, m.l. & minasny, b. (2003): on digital soil mapping.– geoderma, 117, 3–52. doi:10.1016/s0016-7061(03)00223-4 pettijohn, f.j. (1963): chemical composition of sandstone – excluding carbonate and volcanic sands. in: fleischer, m. (ed.): data on geochemistry. geological survey professional paper.– united states department of interior. us government printing office, washington. prasad, a.m., iverson, l.r. & liaw, a., (2006): newer classification and regression tree techniques: bagging and random forests for ecological prediction.– ecosystems, 9, 181–199. doi:10.1007/s10021-005-0054-1. r core team (2017): r: a language and environment for statistical computing. r foundation for statistical computing, vienna, austria. url https://www.r-project. org/. rodríguez-lado, l. & lado, m. (2017): relation between soil forming factors and scaling properties of particle size distributions derived from multifractal analysis in topsoils from galicia (nw spain).– geoderma, 287, 147–156. doi: 10.1016/j.geoderma.2016.08.005 sarbas, b. & nohl, u. (2008): the georoc database as part of a growing geoinformatics network.– in: brady, s.r., sinha, a.k. & gundersen, l.c. (eds.): geoinformatics 2008-data to knowledge, proceedings: u.s. geological survey scientific investigations report 2008-5172 (2008), 42–43. silva, y.j.a.b., nascimento, c.w.a., biondi, c.m., straaten, p., souza jr., v.s. & ferreira, t.o. (2016): weathering rates and carbon storage along a climosequence of soils developed from contrasting granites in northeast brazil.– geoderma, 284, 1–12. doi: 10.1016/j.geoderma.2016.08.009 stefanovits, p.filep, gy.füleky, gy. (2005): talajtan.– mezőgazda kiadó, budapest, 470 p. tóth, g., hengl, t., hermann, t., makó, a., kocsis, m., tóth, b. & berényi üveges, j. (2015): magyarország mezőgazdasági területeinek talajtulajdonság-térképei [soil property maps of the agricultural area in hungary – in hungarian]. institute for environment and sustainability, jrc, ispra, 63 p., doi: 10.2788/318926 újvári, g., varga, a. & balogh-brunstad, zs. (2008): origin, weathering, and geochemical composition of loess in southwestern hungary.– quaternary research, 69, 421–437. doi:10.1016/j.yqres.2008.02.001 van engelen, v. & dijkshoorn, j. (eds.) (2013): global and national soils and terrain digital databases (soter), procedures manual, version 2.0. isric report 2013/04. wageningen, the netherlands: isric — world soil information, 192 p. vaysse, k. & lagacherie, p. (2015): evaluating digital soil mapping approaches for mapping globalsoilmap soil properties from legacy data in languedocroussillon (france).– geoderma regional, 4, 20–30. doi: 10.1016/j.geodrs.2014. 11.003 várallyay, gy., szabóné kele, g., berényi üveges, j., marth, p., karkalik, a. & thury, i. (2010): soil conditions in hungary based on the data from the soil conservation information and monitoring system (sims).– ministry of agricultural and rural development. budapest, 91 p. várallyay, gy. (2013): soil scientific basis of agricultural water management. university of debrecen, service sciences methodology centre, debrecen, 219 p. weiss, a. (2001): topographic position and landforms analysis. poster presentation, esri user conference, san diego, ca. wiesmeier, m., barthold, f., blank, b. & kögel-knabner, i., (2011): digital mapping of soil organic matter stocks using random forest modeling in a semi-arid steppe ecosystem.– plant soil, 340, 7–24. doi:10.1007/s11104-0100425-z xiong, x., grunwald, s., myers, d.b., kim, j., harris w.g. & comerford, n.b. (2014): holistic environmental soil-landscape modeling of soil organic carbon.– environmental modelling & software, 57, 202–215. doi:10.1016/j. envsoft.2014.03.004 2023 | 76/1 | 1–12 | 11 figs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction during the early and middle anisian, the western margin of the palaeotethys ocean of the present dinaric-carpathian-alpine region was characterised by relatively uniform sedimentation (haas et al., 1995; kovács et al., 2011). sea level changes were strongly expressed in the more landward-located areas, such as in the present-day central and western southern alps (gianolla et al., 1998; mietto et al., 2020), whereas they had limited or no effect in the more oceanward positioned platform of the present-day eastern southern alps (buser, 1989). the relatively widespread and uniform sedimentary conditions were terminated during the late anisian due to the more vigorous transtensional tectonics, and a more differentiated topography was established (buser, 1989; haas & budai, 1999; budai & vörös, 2006; balini et al., 2006; berra & carminati, 2010; stefani et al., 2010; velledits et al., 2011; gawlick et al., 2012; mietto et al., 2020; smirčić et al., 2020). extension of the upper crust is evidenced in the area of the present-day julian, carnic, and kamnik-savinja alps, as well as in the karavanke mts. in the formation of a number of small-scale half-grabens filled with breccia and conglomerate of the so-called uggowitz (ugovizza) breccia formation (farabegoli et al., 1985; venturini, 1990; kozur et al., 1994; krainer & lutz, 1995; celarc et al., 2013). the uggowitz breccia formation was deposited in a variety of settings and the stratigraphic successions vary. in the carnic alps, it forms the basal part of a transgressive sequence and is interpreted as a fluvial or deltaic depositional unit (e.g., farabegoli & levanti, 1982; farabegoli et al., 1985; venturini, 1990, 2006). in contrast, in the karavanke mts., in the julian alps, and in the kamnik sediment infill of the middle triassic half-graben below mt. vernar in the julian alps, slovenia luka gale1,2(*), katarina kadivec1,3, marko vrabec1 and bogomir celarc2† 1 university of ljubljana, department of geology, aškerčeva 12, 1000 ljubljana, slovenia; (*corresponding author orcid no. 0000-0002-2524-0073 luka.gale@ntf.uni-lj.si; marko.vrabec@ntf.uni-lj.si) 2 geological survey of slovenia, dimičeva 14, 1000 ljubljana, slovenia; (luka.gale@geo-zs.si) 3 irgo consulting d.o.o., slovenčeva 93, 1000 ljubljana, slovenia; (katarina.kadivec@irgo.si) doi: 10.4154/gc.2023.03 abstract a sediment infill of a small, late anisian–earliest ladinian half-graben, sealed by massive limestone of the schlern formation is exposed on the northeastern slopes of mt. vernar in the eastern julian alps, slovenia. the pre-rift base of the succession is formed by a chaotic mixture of massive limestone and limestone breccia of the anisian platform. sedimentation in the half-graben started with a 20 m thick thinly bedded pink nodular limestone which is informally named here as the vernar member. it consists of microbial carbonate and was probably deposited within the photic zone. the vernar member is overlain by poorly sorted polymict breccias of the uggowitz breccia formation which reaches a thickness of at least 150 m, but pinches out rapidly towards the se graben margin, reflecting the highly asymmetric basin geometry. individual beds of breccia represent successive debris flow deposits. the uggowitz breccia formation is followed by a few metres of sandstone and sandy limestone of the buchenstein formation. the limestone contains abundant grains of shallow marine origin and terrestrial plant fragments. the overlying post-rift schlern formation consists of crudely bedded and massive limestone, covering the graben. the consistent ne-sw strike of the graben-bounding faults and of the smallscale conjugate normal faults observed in the uggowitz breccia formation suggests that the half-graben originated from nw-se directed extension. savinja alps, the uggowitz breccia formation is underand overlain by deeper-marine sediments (kozur et al., 1994; celarc et al., 2013). contemporary regional volcanism added to the lithological diversity resulting from the interplay between tectonics, sea level changes and carbonate production (buser, 1989; bosellini et al., 2003; mietto et al., 2020). celarc et al. (2013) described the uggowitz breccia formation occurrences in the kamnik-savinja alps, but other exposures in the eastern southern alps remain undescribed or are only briefly mentioned. the aim of this research is to present a detailed sedimentological analysis of the uggowitz breccia formation underlying the schlern formation of mt. vernar in the julian alps (slovenia). the succession was briefly mentioned by jurkovšek (1987) and ramovš (2000) but was never investigated in detail. here, we aim to interpret the mechanism of deposition and the depositional environment for the described units, and to offer an interpretation of the basin evolution. 2. geological setting mt. vernar (lat. 46°21′36.25 ,̋ long. 13°51′46.62˝) is a 2225 m a.s.l. high mountain in the julian alps, nw slovenia, a part of the eastern southern alps (fig. 1a). the structure of the julian alps is largely governed by the two alpine thrust systems: the maastrichtian to eocene swto w-vergent dinaric system, and the late oligocene–early miocene sto se-vergent south alpine thrusts. neotectonic nnw-directed shortening starting in the late miocene-pliocene and produced nw-se-striking dextral and ne-sw striking sinistral faults which displace the thrusts (fig. 1b) (poli & zanferarri, 1995; castellarin & cantelli, 2000; placer, 2008; caputo et al., 2010, article history: manuscript received october 08, 2022 revised manuscript accepted december 29, 2022 available online february 23, 2023 keywords: southern alps, middle triassic, half-graben, uggowitz breccia, debris-flow deposits g eo lo gi a c ro at ic a geologia croatica 76/12 goričan et al., 2018, 2022). mt. vernar sits in the dinaric zlatna klippe, which occupies the highest structural position and lies over the south alpine krn nappe (fig. 1b) (jurkovšek, 1986, 1987; goričan et al., 2012, 2018). previous research in the julian alps and the kamnik-savinja alps (celarc et al., 2013) showed that the carbonate platforms of the eastern south alpine domain were drowned during the late anisian. locally formed half-grabens were filled with pelagic red nodular limestone (the loibl formation), pyroclastics, and rhyolites or carbonate breccia (the uggowitz breccia formation), and finally by thin-bedded limestone, grainstone, and subordinate marl (the buchenstein formation). a carbonate platform (the schlern formation) then prograded over the wider area and sealed the half-grabens (celarc et al., 2013). 3. material and methods the area of mt. vernar and its surroundings was mapped at a 1:5.000 scale. since a large part of this area is inaccessible due to rugged alpine terrain, the ne face of mt. vernar was also surveyed with an unmanned aerial vehicle (uav) dji phantom 4 pro and then a 3d model of the exposure was created using structure-from-motion photogrammetry in metashape pro modelling software to get additional insight into the structure and stratigraphy of the subvertical sections of the mountain. the stratigraphic succession of the ne slope of mt. vernar was logged and sampled in four sections. fifty-eight samples were taken from in-situ beds. an additional 29 samples were taken from scree deposits. of these, 10 samples belong to the uggowitz breccia formation, and 19 are derived from the overlying platform (schlern formation). samples from the scree were considered only when their origin was undisputed and only as additional samples. biostratigraphic interpretations are not based on these samples. thin sections of 28 × 47 mm and 75 × 49 mm sizes were made and analysed with a polarizing microscope. carbonates were classified according to dunham (1962), and embry and klovan (1971). as suggested by wright (1992), we use the term calcimudstone as a texture of carbonate rocks as opposed to mudstone used for siliciclastic rocks. the terminology employed for microbial carbona te follows riding (2000). 4. results 4.1. general stratigraphy and structure the logged succession begins with thin-bedded, often nodular pinkish limestone some 20 m thick, which only outcrops in the se part of the exposure (figs. 2, 3). it is informally named here as the vernar member. to the se, the vernar member laterally passes into a chaotic mixture of massive grey limestone and monomictic breccias, which probably belong to the upper anisian contrin formation. we interpret this contact as a nw-dipping low-angle normal fault zone, separating the vernar member from the underlying contrin formation (fig. 3a). the pinkish limestone of the vernar member is cut by neptunian dykes filled with polymictic breccia, identical to the breccias of the overlying uggowitz breccia formation. the topmost layers of the vernar member overlying the normal fault zone are not affected by faulting, suggesting that the fault was active during sedimentation and that its activity terminated before the end of deposition of the vernar member. the vernar member is overlain by a few beds of poorly sorted polymict breccias of the uggowitz breccia formation (figs. 2, 3a). towards the se, these beds pinch out entirely. north-westward, less than 20 m from the vernar member outcrop, the thickness of the uggowitz breccia formation rapidly increases to 35 m (section 2 in fig. 2), and then to more than 150 m in a large outcrop about 150 m to the nw. the lateral juxtaposition of the vernar member with the uggowitz breccia formation in the se part of the exposure (fig. 2) implies the existence of a steep nw-dipping synsedimentary normal fault separating these two units, which is presently covered by scree. this fault must have formed after the deposition of the vernar member but terminated its activity before the end of the deposition of the uggowitz breccia formation, as the prominent topmost breccia layer figure 1. location of the study area. a: geographical position of the julian alps and of the study area (shown by a red dot). the blue rectangle indicates the map area shown in fig. 1b. b: simplified tectonic map of the eastern julian alps (after goričan et al., 2018). data sources: eu-dem digital elevation model (produced using copernicus data and information funded by the european union), europe coastline shapefile (european environmental agency), and digital elevation model with 5 x 5 m raster grid, dem 5, 2006 (public information of slovenia, the surveying and mapping authority of the republic of slovenia). g eologia c roatica gale et al.: sediment infill of the middle triassic half-graben below mt. vernar in the julian alps, slovenia 3 is not transected (fig. 2). breccia beds and subordinate beds and lenses of sandstone in the larger outcrop are cut by numerous small-scale conjugate normal faults (fig. 3b). the faults strike ne-sw and dip towards the se and nw at around 60°. the uggowitz breccia formation is vertically succeeded by approximately 7 m of bedded sandy limestone and sandstone which we attribute to the buchenstein formation. the outcrop of the buchenstein formation is very limited and its nw-ward continuation is only speculative due to extensive cover by scree deposits (fig. 2). immediately nw-ward of our study area, green tuff layers also outcrop (fig. 2). the buchenstein formation is followed by weakly and discontinuously bedded limestone, which passes upwards into the massive limestone of the schlern formation (figs. 2, 3a). the pre-schlern succession is terminated to the nnw by a ne-sw-striking fault with a ~30 m wide fault zone, which forms figure 2. oblique aerial view of the ene face of mt. vernar, showing the interpreted geometry of the stratigraphic formations and structures described in this work (image produced from the photogrammetrically-generated 3d model). the locations of the logged sections described in the text are also shown. figure 3. detailed views of the geological structure of the ene slope of mt. vernar in the photogrammetrically-generated 3d model. refer to fig. 2 for locations. a: view of the se part of the exposure, showing the pinching out of beds and the normal fault controlling the deposition of the vernar member. field of view is rotated to better visualize the original depositional geometry. b: conjugate se-nw-striking, probably synsedimentary normal faults and fractures cutting the uggowitz breccia formation. vertical extent of the field of view is approximately 90 m. g eo lo gi a c ro at ic a geologia croatica 76/14 a prominent narrow gulley in the northern ridge of mt. vernar and dips 65°70° towards the se. we interpret this fault as the master fault of the middle triassic half-graben. the somewhat curved trace of the master fault in map view suggests that it may have a listric geometry with the dip angle decreasing downdip, but this is not clearly visible in the field. on the nnw side of the master fault a few tens of metres of thin-bedded marly limestone, dolostone and marlstone of the (middle?) anisian strelovec formation are exposed below the basal part of the massive limestone of the contrin (?) formation. 4.2. description of the lithological units the succession on the ne slope of mt. vernar was logged in four sections, graphically presented in figure 4. the vernar member was recorded in the lower 15 m of section 2 (fig. 4). pinkish limestone is divided into beds 5–15 cm thick, amalgamated in “packages” ranging in thickness from 20 cm to 100 cm (fig. 5a). some beds are crosscut by neptunian dykes some dm thick, filled with breccia, which is identical in appearance to the breccias described from the uggowitz breccia formation (fig. 5b). the limestone is fenestral microbialite boundstone (fig. 5c, f) and wackestone/packstone. microbialite boundstone (locally representing up to 50% of the rock volume) comprises clumps of peloidal micrite and structureless leiolite. birdseye fenestrae are mostly irregular in shape, a few mm in size, and in some thin sections represent up to 50% of the sample. some are geopetally filled with sediment and cement in the following order: (1) micrite, (2) silt-sized micrite with rare ostracod valves, (3) acicular/fibrous rim cement, with (4) crystal silt and blocky spar filling the remaining space. ostracods with both valves and foraminifers can be found in some of the cementfilled fenestrae. the wackestone/packstone locally represents up to 50% of the samples. it contains small pellets, ostracods with disarticulated or complete carapaces, foraminifers (common endotriada sp., earlandia sp., krikoumbilica sp., rarely small frondicularia sp., reophax sp., endotebanella or ammobaculites sp., and some undetermined involutinids – see fig. 5d), tubiphytes/schamovella-like microproblematica, calcimicrobes in growth positions (fig. 5e), and sporadically also echinoderms and gastropods. the vernar member is followed by the uggowitz breccia formation. the latter was recorded in section 1 (separated from the wall by scree deposits) in a total thickness of 65 m, whereas it is only a few metres thick in other sections (fig. 4). the uggowitz breccia formation is predominantly represented by clastsupported breccia (fig. 6). thinner (5–15 cm) beds and lenses of carbonate sandstone and mudstone occur subordinate to the breccia beds. breccia beds are 0.2–5 m thick (fig. 6a). bed boundaries are irregular, with clasts often protruding from the upper bedding plane (fig. 6b). several beds display internal layers, which are in some cases normally or inversely graded (figs. 6c– d). clasts are poorly sorted, ranging in size from 0.5 cm to 0.5 m. they often represent up to 90% of the rock, strongly dominating over the matrix. clasts are sub-rounded to angular, with sutured, long, and concavo-convex, more rarely tangential contacts. between 55% and 95% of clasts are represented by lithoclasts of carbonate rocks (fig. 7a), light and dark grey in colour, or with pink, red, or yellow hues that can be divided into several groups. the most common microfacies of the carbonate clasts is calcimudstone (group a). group b includes common lithoclasts of grainstone to rudstone with bioclasts and lithoclasts of microbialite (fig. 7b), fenestral peloid grainstone (microbialite), and hofigure 4. logged sections. note that the distribution of the sections in this figure does not correspond to their stratigraphic order or their lateral relationships. see figure 2 for locations. section coordinates (obtained with gnss in wgs 84, september 2019): section 1: lat. 46°21’47.46’’, long. 13°51’56.14’’. section 2: lat. 46°21’41.98’’, long. 13°51’50.91’’. section 3: lat. 46°21’41.98’’, long. 13°51’50.17’’. section 4: lat. 46°21’40.59’’, long. 13°51’47.94’’. g eologia c roatica gale et al.: sediment infill of the middle triassic half-graben below mt. vernar in the julian alps, slovenia 5 mogenous or laminated microbialite boundstone (leiolite and stromatolite). the common bioclasts are tubiphytes/schamovella -like microproblematica (including tubiphytes/schamovella sp. and plexoramea sp.), and cortoids. less common are ostracods, brachiopods, bivalves, echinoderms, foraminifers, and dasycladacean algae. the foraminiferal assemblage within the clasts of group b consists of citaella dinarica (kochansky-devidé and pantić) (fig. 7d–e), pilamminella semiplana (kochanskydevidé and pantić) (fig. 7f), and endotriadella wirzi (koehnzaninetti) (fig. 7g). completely recrystallised limestone represents the clasts of group c, which is next in terms of abundance. less common are the lithoclasts of group d, comprising fenestral peloid-bioclastic packstone, peloid-bioclastic wackestone, peloid packstone, and peloid wackestone with a partly washed matrix. rare clasts of foraminiferal wackestone (group e) contain a high density of the foraminifer pilammina densa pantić (figs. 7h). fenestral calcimudstone or sparse wackestone with some foraminifers and ostracods (group f), together with filament wackestone, and radiolarian wackestone to packstone (fig. 7c) (group g) are very rare among carbonate clasts. subordinate to limestone clasts are clasts of red rhyolite, red, and greenish grey peperite, green tuff, light brown, beige and red sandstone, mudstone, and clasts of fault breccias. the breccia matrix is sandy, locally muddy, and represents only 10–30% of the rock. it is commonly reddish orange in colour, locally greenish grey. it locally consists of up to 50% grains of quartz, feldspar (plagioclase), and some opaque minerals. beds and lenses of sandstone and mudstone are subordinate to the breccia beds, and are between 5 cm and 15 cm thick. mudstone commonly contains small coalified fragments of terrestrial plants. sandstone is fineto coarse-grained. a few beds show boundary-parallel (horizontal) planar lamination (fig. 8a). sand particles are poorly to moderately sorted, with point, long, concavo-convex, and, in some samples, sutured contacts (fig. 8b). approximately 90% of clasts are carbonate lithoclasts, which texturally match the prevailing carbonate clasts described from breccias (see above). quartz, mica, plagioclase, and opaque mine rals, as well as clasts of volcanic rocks and mudstone are figure 5. field view and photomicrographs of the vernar member. a: field photo of the pinkish nodular limestone. b: neptunian dyke cutting the pinkish nodular limestone and filled with breccia. c: fenestral microbialite boundstone. thin section 1264. d: undetermined aragonitic foraminifer. thin section 1270. e: calcimicrobe in growth position. thin section 1272. f: pelletal grainstone (microbialite) with fenestrae. thin section 1272. g eo lo gi a c ro at ic a geologia croatica 76/16 present in subordinate amounts. the matrix (10–40% of the rock volume) is micrite or microsparite, locally limonitic. the uppermost breccia bed shows transitions from a red, to green-grey, and finally an almost black coloured matrix. the clasts in these beds are less variable in lithology, represented only by white, grey, beige, and pink limestone, and lacking clasts of volcanic and volcaniclastic rocks. the buchenstein formation overlying the uggowitz breccia formation consists of thin beds of dark brown sandstone and sandy limestone, which often contains coalified plant fragments. the sandstone beds range from 4 cm to 20 cm in thickness. the sandstone is moderately to well sorted (fig. 9a). depending on the amount of micritic carbonate matrix, grains are in point or long contacts. angular carbonate lithoclasts predominate: micritic and microsparitic clasts represent 50% of all clasts, and an additional 12% of clasts are completely recrystallised limestone. clasts of volcaniclastic rocks, quartz, feldspar, and of undetermined opaque minerals represent 35% of clasts. bioclasts, such figure 6. field aspect of breccia within the uggowitz breccia formation. a: well-expressed bedding. beds are laterally continuous. b: upper surface of the breccia bed. note the clasts protruding from the upper bed surface, characteristic of the debris flow deposits. c: amalgamation (along the irregular line) of two (or more) layers of breccia. d: stacking of several inversely or normally graded layers of breccia (block rotated by 90° with respect to the bedding). e: rare example of matrixsupported breccia. g eologia c roatica gale et al.: sediment infill of the middle triassic half-graben below mt. vernar in the julian alps, slovenia 7 as bivalve and brachiopod shells, gastropods, ostracods, foraminifers, and echinoderms are rare, or are only locally more abundant. some sandstone beds also contain centimetre-sized lithoclasts (fig. 9b). limestone and sandy limestone beds are 15–25 cm thick. microfacies types include calcimudstone, laminated calcimudstone, and peloid wackestone, peloid packstone with partly washed matrix (fig. 9c), bioclastic-intraclastic packstone (fig. 9d–e), wackestone with tubiphytes/schamovella-like microproblematica (fig. 9f), and oncoid rudstone. the calcimudstone locally contains a small admixture of silt-sized terrigenous material, pellets, and a few bioclasts (echinoderms, foraminifers, ostracods). in addition to peloids, the peloid packstone with partly washed matrix contains subordinate bivalves, foraminifers (?trochammina sp., glomospirella sp., and endothyracea), echinoderms, gastropods, and ostracods, as well as small amounts of fine grains of quartz, feldspar, and volcanics. the bioclastic-intraclastic packstone is relatively rich in foraminifers (fig. 10). involutinidae parvalamella friedli (kristan-tollmann) and ?aulotortus? eotriasicus zaninetti, rettori and martini, as well as duostominoidea are abundant and well preserved. the specimens determined as ?aulotortus? eotriasicus zaninetti, rettori, and martini are somewhat smaller than the holotype and the paratypes (0.8–1.6 mm in diameter, according to zaninetti et al., 1994), and display glomospiral initial coiling, whereas only small figure 7. clast composition within the uggowitz breccia formation with some important microfacies types and microfossils. a: grain-supported fabric and polymict clasts. thin section 1303a. b: grainstone with bioclasts and microbialite intraclasts. the two largest grains are tubiphytes/schamovella-like microproblematica. clast from breccia. thin section 1304. c: clast of radiolarian wackestone to packstone. thin section 1293. d–e: citaella dinarica (kochansky-devidé and pantić) within a clast. off-centred section. thin section 1288. f: pilamminella semiplana (kochansky-devidé and pantić) within a clast. thin section 1297. g: endotriadella wirzi (koehn-zaninetti) within a clast. thin section 1293. h: pilammina densa pantić within a clast. thin section 1304. g eo lo gi a c ro at ic a geologia croatica 76/18 figure 8. field view and microfacies of sandstone. a: parallel horizontal lamination. b: photomicrograph of sandstone from the uggowitz breccia formation. thin section 1300. figure 9. microfacies of the buchenstein formation. a: sandstone. thin section 1256a. b: large lithoclast in sandstone. thin section 1802. c: partly washed peloid packstone. thin section 1801. d: bioclastic-intraclastic packstone. thin section 1275. e: bioclastic-intraclastic packstone. the white arrowhead points to parvalamella friedli (kristan-tollmann). the black arrowhead with white outline points to ?aulosina sp. thin section 1266. f: wackestone with tubiphytes/schamovella-like microproblematica (arrowhead). thin section 1253. g eologia c roatica gale et al.: sediment infill of the middle triassic half-graben below mt. vernar in the julian alps, slovenia 9 deviations from the planispiral coiling have been observed in the type material of this species (zaninetti et al., 1994). the biconcave shape of some specimens (e.g., figs. 10a, d) is probably due to stylolitization and is not a primary characteristic of them. other important species from this microfacies include lamelliconus ex gr. ventroplanus (oberhauser) sensu (rettori, 1995), ?aulosina sp., and ?trocholina cf. turris frentzen. other bioclasts present include bivalve shells, echinoderms, gastropods, ostracods, and tubiphytes/schamovella-like microproblematica. some limestone beds become progressively sandier towards the top, and a few end with a horizon of mud-supported breccia. one limestone bed was found to hold small, disarticulated bivalves on the upper bedding plane. transition from the buchenstein formation to the schlern formation is through several beds 25–80 cm thick in total thickness of 6 m. light grey limestone is texturally poorly sorted bioclastic wackestone (fig. 11a), intraclastic-bioclastic grainstone, and oncoid rudstone (fig. 11b,c). the wackestone contains cortoids, echinoderms, bryozoans, gastropods, bivalves, ostracods, and foraminifers (?ammobaculites sp., endothyracea, trochammina almtalensis koehn-zaninetti). micritic intraclasts predominate in the intraclastic-bioclastic grainstone. thalamid and other sponges, tubiphytes/schamovella-like microproblematica, dasycladacean algae (fig. 11d), bivalves, echinoderms, foraminifers, and ostracods are present. foraminifers include ammobaculites sp. or endotebanella sp. (“earlandinita oberhauseri salaj” = “earlandinita elongata salaj” in salaj et al. 1967) (fig. 11e), reophax sp., endothyracea, endotriadella wirzi (koehn-zaninetti) (fig. 11f), ?“tetrataxis” nanus kristan, and duostominoidea. massive limestone prevails upwards forming near-vertical walls that could not be sampled in situ. 5. discussion we interpret the structure of the ne slope of mt. vernar as a middle triassic half-graben with its sediment infill thickening northwestward towards the ne-sw-striking master fault and pinching out towards the se edge of the half-graben (fig. 2). the master fault was also (re)activated after the sedimentation of the anisian mt. vernar succession, as a significant vertical slip can be determined from the elevated position of the contrin (?) formation on the other side of the master fault. from the consistent ne-sw strike of the bounding faults and of the conjugate extensional faults and fractures within the half-graben we conclude that the half-graben formed during nw-se oriented extension (in present-day reference frame). the recorded succession is comparable, though not completely identical to some other examples of graben-filling succesfigure 10. foraminifers from the buchenstein formation. thin sections, not shown in fig. 4, are cut from samples collected from the scree deposit. foraminifera from these samples are illustrated here solely because of their good preservation. a-c: ?aulotortus? eotriasicus zaninetti et al. note that some specimens appear biconcave due to stylolitization. thin sections: 1266 (figs. a, c), 1255 (fig. b). d-e: ?aulosina sp. thin sections 1255 (fig. d), 1266 (fig. e). f-g: lamelliconus ex gr. ventroplanus (oberhauser) sensu rettori (1995). thin section 1266 (fig. f). specimen in figure g is from the sample from scree. h-i: ? trocholina cf. turris frentzen. note the papillae in the umbilical mass (arrowhead) in fig. i. thin sections: 1255 (fig. h), 1266 (fig. i). j-k: ?duostominidae. sample from scree. l: duostomina biconvexa kristan-tollmann. arrowheads point to parvalamella friedli (kristan-tollmann). sample from scree. m: duostomina alta kristan-tollmann. thin section 1258. n: ?diplotremina altoconica kristan-tollmann. thin section 1266. o: parvalamella friedli (kristan-tollmann). sample from scree. g eo lo gi a c ro at ic a geologia croatica 76/110 sions from the julian and the kamnik-savinja alps occurring within the late anisian–early ladinian time interval (celarc et al., 2013). the most notable difference is that the uggowitz breccia formation on the slopes of mt. vernar is not underlain by the radiolarian-rich loibl formation. instead, the limestone of the vernar member below the uggowitz breccia formation is riddled with fenestrae, which seem to be either constructional or are the product of early diagenesis (the late diagenetic origin of fenestrae can be excluded based on ostracods found within the micrite filling the fenestrae). based on the presence of calcimicrobes in growth position, we suggest that deposition still took place within the photic zone. the normal fault zone between the massive limestone of the contrin (?) formation and the vernar member indicates formation of a shallower basin, filled with the nodular limestone prior to formation of the much steeper fault and deposition of the uggowitz breccia formation. the timing of the deposition of the uggowitz breccia formation has to be estimated on the basis of superposition and/or the age of the youngest clasts found in the breccia. whereas most limestone clasts with fossils are middle to late anisian in age (based on the foraminifera citaella dinarica, pilamminella semiplana, endotriadella wirzi, and pilammina densa; see rettori, 1995), the limestone clasts with radiolarians and filaments probably originate from the loibl formation, which has been dated in the kamnik-savinja alps to the illyrian (kolar-jurkovšek, 1983; petek, 1998; buser et al., 2008; celarc et al., 2013). based on these clasts, the uggowitz breccia below mt. vernar was most likely deposited during the illyrian or somewhat later. this is in accordance with the sequence chronostratigraphic scheme for the northern julian alps by gianolla et al. (1998), and previous research by celarc et al. (2013). the large proportion of clasts (up to 90% of the rock volume), their poor sorting, the presence of internal layering, inverse and normal grading, and especially the irregular nature of the upper bedding planes, which are studded by protruding clasts, suggests that breccias within the uggowitz breccia formation are debris flow deposits (sohn, 2000; prothero & schwab, 2013). the internal layering observed within the individual beds of breccia results from the stacking of several debris-flow surges (sohn, 2000). the subordinate beds of sandstone were probably deposited by turbidity currents generated by flow transformation of the gravelly debris flow (mohrig et al., 1998; sohn, 2000). the deposition of the uggowitz breccia formation within a submerged half-graben fits either the coastal marine gulf basin or the coastal/shelf basin with carbonate facies model, or both, since the first can evolve into the latter (leeder & gawthorpe, 1987). according to the coastal marine gulf and coastal/shelf basins, breccias represent footwall submarine fans and/or peri-platform talus generated through slumping and debris flow mechanisms. the buchenstein formation of the logged section was also deposited in a marine environment, as evidenced by the common presence of foraminifers and echinoderms. we interpret these clasts as redeposited material of shallower origin. bioclasts of shallow-marine origin, most notably dasycladacean algae and corals, also predominate within the buchenstein formation in half-grabens previously documented by celarc et al. (2013). the concomitant occurrence of terrestrial plant fragments and sandy terrigenous material suggests close proximity to the coast, figure 11. microfacies of the schlern formation. a: bioclastic wackestone. thin section 1807. b: intraclastic-bioclastic grainstone. thin section 1251. c: intraclasticbioclastic grainstone. thin section 1261. d: dasycladacean algae in intraclastic-bioclastic grainstone. thin section 1262. e: ammobaculites sp. or endotebanella sp. (“earlandinita oberhauseri salaj” = “earlandinita elongata salaj” in salaj et al., 1967). thin section 1267. f: endotriadella wirzi (koehn-zaninetti). thin section 1267. g eologia c roatica gale et al.: sediment infill of the middle triassic half-graben below mt. vernar in the julian alps, slovenia 11 although small plant fragments may be transported far from the shore either as floating material or via turbidity currents. lenses and thin tongues of pebble to cobble size clasts in some limestone beds could represent terminations of lower-viscosity debris flows in a subaqueous environment (nemec & steel, 1984). the schlern formation formed as a carbonate platform under subtidal conditions and is free from terrigenous input. this suggests a migration of the coastline landwards and the relative rise of sea level. recorded foraminifera are of insufficient stratigraphic resolution or have insufficiently defined timespans to determine their precise age. according to gianolla et al. (1998) and mietto et al. (2020), the base of the schlern formation is latest illyrian to fassanian in age. 6. conclusions the stratigraphic succession below mt. vernar in the julian alps represents a sedimentary fill of a half-graben formed during crustal extension at the end of the anisian. the beginning of extension is marked by the formation of a low-angle normal fault zone and deposition of the vernar member, filling the newly created basin and stepping over the fault scarp. the deposition of the vernar member probably took place within the photic zone. following deposition of the vernar member, a steeper fault created a deeper half-graben extending in the present-day ne–sw direction. the sedimentary infill of this half-graben comprises the uggowitz breccia formation and the buchenstein formation. the latter is overlain by the prograding carbonate platform of the schlern formation. the recorded succession is similar to previously recorded examples from the kamnik-savinja alps, the julian alps, the karavanke mts., and the external dinarides, where the uggowitz breccia formation is underand overlain by platform carbonates. the uggowitz breccia from the carnic alps, in contrast, was deposited on top of a more substantial unconformity and is instead interpreted as a fluvial or paralic deposit, forming the base of a new transgression. acknowledgement this research was financially supported by the slovenian research agency (research core funding no. p1-0011 to l.g. and b.c. and no. p1-0195 to m.v.). we thank the technical staff of the geological survey of slovenia for the preparation of thin sections. we particularly thank the reviewers for their suggestions and useful comments, which helped us in our interpretation of the field data. references balini, m, jurkovšek, b. & kolar-jurkovšek, t. (2006): new ladinian ammonoids from mt. svilaja (external dinarides, croatia).– riv. ital. palaeont. stat., 112, 383–395. doi: 10.13130/2039-4942/6348 berra, f. & carminati, e. (2010): subsidence history from a backstripping analysis of the permo-mesozoic succession of the central suthern alps (northern italy).− basin res., 22, 952–975. doi: 10.1111/j.1365-2117.2009.00453.x bosellini, a., gianolla, p. & stefani, m. (2003): geology of the dolomites.− episodes, 26, 181–185. doi: 10.18814/epiiugs/2003/v26i3/005 budai, t. & vörös, a. (2006): middle triassic platform and basin evolution of the southern bakony mountains (transdanubian range, hungary).− riv. it. palaeont. strat., 112, 359–371. doi: 10.13130/2039-4942/6346 buser, s. (1989): development of the dinaric and the julian carbonate platforms and of the intermediate slovenian basin (nw yugoslavia).− boll. soc. geol. ital., 40, 313–320. buser, s., kolar-jurkovšek, t. & jurkovšek, b. (2008): the slovenian basin during the triassic in the light of conodont data.− boll. soc. geol. ital., 127, 257–263. caputo, r., poli, m.e. & zanferrari, a. (2010): neogene–quaternary tectonic stratigraphy of the eastern southern alps, ne italy.− j. struct. geol., 32, 1009–1027. doi: 10.1016/j.jsg.2010.06.004 castellarin, a. & cantelli, l. (2000): neo-alpine evolution of the southern eastern alps.− j. geodyn., 30, 251–274. doi: 10.1016/s0264-3707(99)00036-8 celarc, b., goričan, š. & kolar-jurkovšek, t. (2013): middle triassic carbonate-platform break-up and formation of small-scale half-grabens (julian and kamnik-savinja alps, slovenia).− facies, 59, 583–610. doi: 10.1007/s10347-0120326-0 dunham, r.j. (1962): classification of carbonate rocks according to depositional texture.–in: han, w.e. (ed.): classification of carbonate rocks, a symposium. amer. ass. petrol. geol mem., 108–121. doi: doi.org/10.1306/m1357 embry, a.f. & klovan, j.e. (1971): a late devonian reef tract on northeastern banks island.− nwt bull. can. petrol. geol., 19, 730–781. farabegoli, e. & levanti, d. (1982): triassic stratigraphy and microfacies of the monte pleros (western carnia, italy).– facies, 6, 37–58. farabegoli, e., jadoul, f. & martines, m. (1985): stratigrafia e palaeogeografia anisiche delle alpi giulie occidentali (alpi meridionali – italia).− riv. it. palaeont. strat., 91, 147–196. gawlick, h.-j., goričan, š., missoni, s. & lein, r. (2012): late anisian platform drowning and radiolarite deposition as a consequence of the opening of the neotethys ocean (high karst nappe, montenegro).− bull. soc. géol. france, 183, 349–358. doi: 10.2113/gssgfbull.183.4.349 gianolla, p., de zanche, v. & mietto, p. (1998): triassic sequence stratigraphy in the southern alps (northern italy): definition of sequences and basin evolution.− in: de graciansky, p.c., hardenbol, j., jacquin, t. & vail, p.r. (eds.): mesozoic and cenozoc sequence stratigraphy of european basins.− sepm spec. publ., 60, 719–746. doi: 10.2110/pec.98.02.0719 goričan, š., košir, a., rožič, b., šmuc, a., gale, l., kukoč, d., celarc, b., črne, a.e., kolar-jurkovšek, t., placer, l. & skaberne, d. (2012): mesozoic deep-water basins of the eastern southern alps (nw slovenia).− j. alpine geol., 55, 1–43. goričan, š., žibret, l., košir, a., kukoč, d. & horvat, a. (2018): stratigraphic correlation and structural position of lower cretaceous flysch-type deposits in the eastern southern alps (nw slovenia).− int. j. earth sci., 107, 2933–2953. doi: 10.1007/s00531-018-1636-4 goričan, š., horvat, a., kukoč, d. & verbič, t. (2022): stratigraphy and structure of the julian alps in nw slovenia.– folia biolog. geolog., 63, 61–83. doi: 10.3986/fbg0098 haas, j. & budai, t. (1999): triassic sequence stratigraphy of the transdanubian range (hungary).− geol. carpathica, 50, 459–475. haas, j., kovács, s., krystyn, l. & lein, r. (1995): significance of late permian-triassic facies zones in terrane reconstructions in the alpine-north pannonian domain.− tectonophysics, 242, 19–40. doi: 10.1016/0040-1951(94)00157-5v jurkovšek, b. (1986): osnovna geološka karta sfrj 1:100000, list beljak in ponteba l33−52, l33−51 [basic geological map of sfry 1:100000, beljak and ponteba sheet – in slovenian].– geološki zavod ljubljana, ljubljana, zvezni geološki zavod, beograd. jurkovšek, b. (1987): osnovna geološka karta sfrj 1:100000. tolmač za list beljak in ponteba, l33−52, l33−51 [basic geological map of sfry 1:100000, geology of the beljak and ponteba sheet – in slovenian].– geološki zavod ljubljana, ljubljana, zvezni geološki zavod, beograd, 58 p. kolar-jurkovšek, t. (1983): srednjetriasni konodonti slovenije.− rudarskometalurški zbornik: revija za geologijo, rudarstvo in metalurgijo, 30, 323–364. kovács, s., sudar, m., grădinaru, e., gawlick, h.-j., karamata, s., haas, j., péro, c., gaetani, m., mello, j., polák, j., aljinović, d., ogorelec, b., kolar-jurkovšek, t., jurkovšek, b. & buser, s. (2011): triassic evolution of the tectonostratigraphic units of the circum-pannonian region.− jb. geol. b.-a., 151, 199–280. kozur, h.w., krainer, k. & mostler, h. (1994): middle triassic conodonts from the southern karawanken mountains (southern alps) and their stratigraphic importance.− geol. paläont. mitt. innsbruck, 19, 165–199. krainer, k. & lutz, d. (1995): middle triassic basin evolution and stratigraphy in the carnic alps (austria).− facies, 33, 167–184. doi: 10.1007/bf02537450 leeder, m.r. & gawthorpe, r.l. (1987): sedimentary models for extensional tilt-block/half-graben basins.– in: coward, m.p., dewey, j.f. & hancock, p.l. (eds): continental extensional tectonics.− geol. soc. spec. publ., 28, 139–152. doi: 10.1144/gsl.sp.1987.028.01.11 mietto, p., avanzini, m., belvedere, m., bernardi, m., dall vecchia, f.m., o’orazi porchetti, s., gianolla, p. & petti, f.m. (2020): triassic tetrapod ichnofossils from italy: the state of the art.− j. mediterr. earth sci., 12, 83–134. mohrig, d., whipple, k.x., hondzo, m., ellis, c. & parker, g. (1998): hydroplaning of subaqueous debris flows.− gsa bull., 110, 187–394. doi: 10.1130/0016-7606(1998)110<0387:hosdf>2.3.co;2 g eo lo gi a c ro at ic a geologia croatica 76/112 nemec, w. & steel, r.j. (1984): alluvial and coastal conglomerates: their significant features and some comments on gravelly mass-flow deposits.– in: koster, e.h. & steel, r.j. (eds): sedimentology of gravels and conglomerates. can. soc. petrol. geol. mem., 10, 1–31. petek, t. (1998): scythian and anisian beds in the quarry near hrastenice and important finds of upper anisian fossils.− geologija, 40, 119–151. doi: 10.5474/geologija.1997.006 placer, l. (2008): principles of the tectonic subdivision of slovenia.− geologija, 51, 205–217. doi: 10.5474/geologija.2008.021 poli, m.e. & zanferrari, a. (1995): dinaric thrust tectonics in the southern julian prealps (eastern southern alps, ne italy).– in: vlahović, i. & velić, i. (eds): proceedings of the first croatian geological congress. institute of geology, croatian geological society, zagreb, 2, 465–468. prothero, d.r. & schwab, f. (2013): sedimentary geology: an introduction to sedimentary rocks and stratigraphy.– wh freeman and company, new york, 575 p. ramovš, a. (2000): über die zlatnaplatte sensu kossmat, 1913, slatna-decke sensu buser, 1986, slatna-überschiebung sensu jurkovšek, 1987 und triglav-decke sensu ramovš, 1985.− geologija, 43, 109–113. doi: 10.5474/geologija.2000.010 rettori, r. (1995): foraminiferi del trias inferiore e medio della tetide: revisione tassonomica, stratigrafia ed interpretazione filogenetica.− uni. geneve, publ. départ. géol. paléont., 18, 1–107. riding, r. (2000): microbial carbonates: the geological record of calcified bacterial-algal mats and biofilms.− sedimentology, 47, 179–214. doi: 10.1046/j.1365 3091.2000.00003.x salaj, j., biely, a. & bystrický, j. (1967): trias-foraminiferen in den westkarpaten.− geol. práce, 42, 119–136. smirčić, d., aljinović, d., barudžija, u. & kolar-jurkovšek, t. (2020): middle triassic syntectonic sedimentation and volcanic influence in the central part of the external dinarides, croatia (velebit mts.).− geol. quarterly, 64, 220–239. doi: 10.7306/gq.1528 sohn, y.k. (2000): coarse-grained debris-flow deposits in the miocene fan deltas, se korea: a scaling analysis.− sediment. geol., 130, 45–64. doi: 10.1016/s00370738(99)00099-8 stefani, m., furin, s. & gianolla, p. (2010): the changing climate framework and depositional dynamics of triassic carbonate platforms from the dolomites.− palaeogeogr. palaeoclimatol. palaeoecol., 290, 43–57. doi: 10.1016/j.palaeo.2010.02.018 velledits, f., péró, c., blau, j., senowbari-daryan, b., kovács, s., piros, o., pocsai, t., szügyi-simon, h., dumitrică, p. & pálfy, j. (2011): the oldest triassic platform margin reef from the alpine-carpathian region (aggtelek, ne hungary): platform evolution, reefal biota and biostratigraphic framework.− riv. it. palaeont. strat., 117, 221–268. doi: 10.13130/2039-4942/5973 venturini, c. (1990): geologia delle alpi carniche centro orientali.– comune di udine, museo friulano di storia naturale, udine. venturini, c. (2006): evoluzione geologica delle alpi carniche.− ed. mus. friulano stor. nat., 48, 1–208. wright, v.p. (1992): a revised classification of limestones.− sed. geology, 76, 177–185. doi: 10.1016/0037-0738(92)90082-3 zaninetti, l., rettori, r. & martini, r. (1994): aulotortus ? eotriasicus, n.sp., un nuovo foraminifero del trias medio (anisico) delle dinaridi ed ellenidi.− boll. soc. palaeont. ital., 33, 43–49. 2021 | 74/3 | 253–271 | 11 figs. | 5 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction in most parts of the pannonian basin system (pbs), a large sedi­ mentary area between the mountain ranges of the alps, carpathi­ ans and dinarides, the pliocene epoch is characterized by the deposition of predominantly fluvial sediments and sediments de­ posited in wetlands and small freshwater lakes (magyar et al., 1999; 2013). only along the southern edge of the pbs was a large freshwater lake formed, namely the paludina lake (neumayr & paul, 1875) (fig. 1). today it is known as lake slavonia (harzhauser & mandić, 2008; mandic et al., 2015; neubauer et al., 2015). the lake is named after paludina, a freshwater snail, the evolutionary lineage of which was used to divide the pliocene deposits of the southern part of the pbs into the lower, middle and upper paludina beds (neumayr & paul, 1875; jenko, 1944; ožegović, 1944; marinescu & papaianopol, 1995; lubenescu & lubenescu, 2008; rundić et al., 2016). subsequently, the name of the genus paludina was replaced by the name viviparus, so that today we are talking about the lower, middle and upper viviparus beds (vb in further text) (mandić et al., 2015). reconstruction of the composition and provenance of the clastic detritus is a complex problem. it can be solved satisfacto­ rily if the data on the modal and chemical composition of the de­ tritus and the data from palaeotransport measurements in the sedimentary basin are used together. the composition of the de­ tritus is primarily a reflection of the geological setting, and thus the geotectonic position of the source area. however, modifying factors such as physical and chemical weathering, relief, climate, mineral assemblage and provenance of the pliocene viviparus beds from the area of vukomeričke gorice, central croatia kurečić, tomislav1,*, kovačić marijan2 and grizelj anita1 1 croatian geological survey – hgi-cgs, sachsova 2, hr-10 000 zagreb, croatia; (*corresponding author: tkurecic@hgi-cgs.hr) 2 university of zagreb, faculty of science, department of geology, horvatovac 102b, hr-10 000 zagreb, croatia doi: 10.4154/gc.2021.16 abstract viviparus beds are sediments deposited in lacustrine and fluvial freshwater environments (lake slavonia) during the pliocene and the earliest pleistocene. a detailed field study and mineralogical, petrographic and chemical analyses were carried out to determine their composition and origin in the area of vukomeričke gorice, central croatia. viviparus beds are characterized by the vertical and lateral exchange of mineralogically and chemically mature pelites and sands. pelitic sediments consist mainly of detrital quartz, calcite, dolomite and feldspar grains, with smectite as the most common clay mineral. quartz and the most resistant lithic fragments dominate the sandy detritus. the composition of the sediments indicates their origin from the recycled orogen, while their textural immaturity suggests a short transport distance. most of the material was re-deposited from the underlying upper miocene sediments, originally of alpine provenance. a lesser proportion originated from palaeogene sediments, triassic carbonate rocks, basic or acidic magmatic rocks and metamorphites. the medvednica and žumberak mts. were the most important source areas, while a smaller proportion of the material could have come from the moslavačka gora mt. and banovina region. the uniform composition of the viviparus beds over the entire vertical distribution of the sediments clearly indicates that the source areas did not change during their deposition. a significant change from the texturally and compositionally mature upper miocene clastic detritus of alpine origin, to the texturally immature material of the viviparus beds of local origin is a consequence of compression and inversion of the previously extensional basin resulting in the uplifting and erosion of the mountains within the sw part of the pannonian basin system. and also the length and type of transport can significantly influ­ ence the final composition of the detritus (basu, 1985; mor­ ton & hallsworth, 1994, 1999; von eynatten & dunkl, 2012). large amounts of clastic detritus have accumulated since the beginning of the miocene in the now predominantly flat area of the pbs (mattick et al, 1988; juhász, 1991; juhász & magyar, 1992; vakarcs et al., 1994; magyar et al, 1999; thamó-boszó & juhász, 2002; kovačić & grizelj, 2006; thamóné boszó et al., 2006; thamóné boszó & kovács, 2007). in the south-western part of the pbs, along the southern edge of the north croatian basin (ncb) (sava depres­ sion), a 4 km thick sequence was deposited (fig. 1) (saftić et al., 2003; troskot-čorbić et al., 2009). studies of the composition and origin of this material have shown that in the earlier stages of basin development, the com­ position of detritus varies locally. sources of material were either located further south in the dinarides or were locally derived el­ evated blocks within the basin (šćavničar, 1979; pavelić et al., 2003; kovačić et al., 2011; pavelić et al., 2016; gri­ zelj et al., 2017, 2020). in contrast, the composition of the up­ per miocene detritus is very uniform and its sources were mainly the alps and the western carpathian mountains (šimunić & šimunić, 1987; kovačić & grizelj, 2006; grizelj et al., 2007; kovačić et al., 2011; pavelić & kovačić, 2018). there were no detailed investigations on the composition and provenance of the detritus comprising the pliocene deposits. however, it was expected that the change of tectonic regime from article history: manuscript received december 11, 2020 revised manuscript accepted june 23, 2021 available online october 13, 2021 keywords: viviparus beds, pliocene, mineral assemblage, provenance g eo lo gi a c ro at ic a 254 geologia croatica 74/3 extension to compression, characteristic for the pliocene epoch in the sw part of the pbs (pavelić, 2001; tomljenović & csontos, 2001; van gelder et al., 2015), formed new local sources of clastic detritus. furthermore, pliocene climate varia­ tions described in adjacent areas, especially changes in dry and wet periods (fedorov et al., 2013; willeit et al., 2013), must have been reflected in the amount and type of derived clastic de­ tritus and its mineralogical maturity. the aim of this study was to determine the mineral and chemical composition and maturity of the vb and, based on this, to determine their source rock composition and provenance. these results will shed light on whether the provenance of the clastic detritus changed from regional to local during deposition of the vb. such a change would be indicative of basin inversion, i.e., the onset of a new compressional phase in the evolution of the pbs. the study was conducted mainly on vukomeričke figure 1. sketch showing the pannonian basin system and its surroundings with the deposition centres of the sub-basins (the thickness of the ng-q basin fill is compiled according to royden & horváth (1988)). the extension of pliocene lake slavonia is outlined with a dashed black line (modified according to neubauer et al. (2015) and mandic et al. (2015)). the area shown in figure 2 is marked by a black rectangle. figure 2. surface distribution of the pliocene viviparus beds (black) on the territory of the republic of croatia (redrawn according to the geological map of the republic of croatia on a scale of 1:300.000 (hgi-cgs, 2009)). the sampling sites are marked with white dots and numbers. spatial reference: htrs96/croatiatm. g eologia c roatica 255kurečić et al.: mineral assemblage and provenance of the pliocene viviparus beds from the area of vukomeričke gorice, central croatia gorice, an area where the vb are best exposed at the surface. for comparison with other areas, additional sites on psunj mt. & dilj mt. in slavonia and in the banovina region, respectively, were studied (fig. 2). 2. geological setting north croatian basin (sw marginal part of pbs) the north croatian basin (ncb) is located in the southwestern part of the pbs. pannonian basin system is a large extension structure located in central and south­eastern europe and sur­ rounded by the mountain ranges of the alps, carpathians and dinarides (fig. 1). the development of the pbs commenced in the early miocene as a consequence of a continental collision and subduction of the eurasian plate beneath the apulian plate (and other continental fragments) from the south. this process caused thermal perturbations of the upper mantle, resulting in the weak­ ening and extension of the crust and formation of a back­arc type sedimentary basin (royden, 1998; horváth, 1993, 1995; kováč et al., 1998; matenco & radivojević, 2013). pa­ laeogeographically, the pbs covered most of central paratethys, the realm formed between the eocene and oligocene by the sep­ aration of western paratethys into the paratethys and the medi­ terranean sea (rőgl, 1999). sedimentation in the ncb began about 18 ma ago in the syn-rift phase of basin development and is characterized by a large transgressive-regressive cycle (man­ dic et al., 2012; pavelić & kovačić, 2018). in the transgres­ sive part of the cycle, mainly clastic sediments were deposited first in alluvial and saline lake environments, and then in fresh­ water lacustrine environments, followed by mainly marine car­ bonate sediments (pavelić & kovačić, 1999; kovačić et al., 2011; pavelić et al., 2016). this period is also characterized by strong volcanic activity (mandic et al., 2012; pavelić & kovačić, 2018; brlek et al., 2020; marković et al., 2021). deposition of marine sediments is a consequence of the ingres­ sion of the paratethys sea into the ncb area in the early middle miocene (ćorić et al., 2009; mandic et al., 2012; pavelić figure 3. geological map of the area of: a) vukomeričke gorice and banovina; b) and c) slavonia with indicated sampling sites. the map was produced using the geological map of the republic of croatia at the scale of 1:300.000 (hgi-cgs, 2009) and was partly modified according to the field data. the sampling sites are marked with white dots and numbers. spatial reference: htrs96/croatiatm. g eo lo gi a c ro at ic a 256 geologia croatica 74/3 & kovačić, 2018; brlek et al., 2020). marine sedimentary environments existed until the end of the middle miocene, when the gradual retreat of the paratethys sea led to the formation of lake pannon 11.6 ma ago (müller et al., 1999; piller et al., 2007; magyar & geary, 2012). a regressive sedimentation cycle started during the sarmatian in the post­rift phase of basin development. in this cycle, predominantly clastic sediments were deposited, first in a brackish lake and later in freshwater lake and fluvial environments (pavelić, 2001; kovačić et al., 2011; pavelić & kovačić, 2018). vukomeričke gorice the vukomeričke gorice area represents a series of hills in the central part of the republic of croatia. they are located about 20 km south of zagreb, are about 30 km long and trend in a nw­se direction (fig. 2). geologically, they represent the remains of several horsts of smaller dimensions, the formation of which is the re­ sult of vertical movements along faults of the predominantly di­ naric direction (filjak, 1951; velić, 1983) and subsequent horizontal displacements of the blocks along the more recent strike­ slip faults (pikija, 1987a, b). the oldest sediments that occur on the surface and at the same time cover most of the vukomeričke gorice area are pliocene sediments deposited in lake slavonia (pikija, 1987a, b; mandic et al., 2015). the northern part of the vukomeričke gorice area is covered with plio-quaternary depos­ its (šikić et al., 1978; 1979), and the north-eastern margin with pleistocene sediments (pikija, 1987a, 1987b) (fig. 3a). pliocene sediments in the area of vukomeričke gorice are differentiated as an informal unit; the viviparus beds (pikija, 1987a, 1987b; hgi, 2009), or as sediments of the lonja forma­ tion (cvetković, 2013). the same deposits belong to the vr­ bova fm., as recently described on a new geological map of požeška mt. (halamić et al., 2019). pikija (1987a) assumes an unconformity between the upper miocene sediments and the pliocene sediments of the vb due to lithological differences. in contrast, cvetković (2013) pointed to the continuity of depo­ sition at the miocene/pliocene boundary on the profiles covering the north-eastern margin of vukomeričke gorice. within the sediments themselves, no division into lower, middle or upper vb was made. on the basis of the fossil assemblage (molluscs) how­ ever, it was found that the sediments of the lower and upper vb were deposited in the area of the vukomeričke gorice, while no fossil evidence was found for the middle vb (pikija, 1987a; mandic et al., 2015). the lower parts of the vb are dominated by various clays interspersed with sand and gravel. they also contain rare sand­ stone and lignite layers (šebečić, 2010). the upper vb were only found in the north-eastern part of vukomeričke gorice, where they lie directly on the lower vb. they consist of gray and yellow-brown sands, yellow, blue and gray clays, fine-grained gravel and occasionally contain lignite lenses (pikija, 1987a). the sand is predominantly very poorly sorted and contains up to 40 % of peliteor up to 35 % of gravel-sized detritus, so that it is defined as silty sand, silty-gravelly sand or clayey sand (kurečić, 2017). well sorted sand rarely occurs. according to their median value they belong to the group of fine, medium or coarse-grained sands. among the pelitic sediments, very poorly sorted silt predominates. depending on the sand and clay content, the silt is defined as clayey silt, sandy-clayey silt or clayey-sandy silt. rare occurrences of gravel are characterized by clast sup­ ported and poorly sorted fabric, occasionally with a fining up­ wards trend. sediments with similar lithological characteristics are found in the vb near novska on the southwestern slopes of psunj mt. (fig. 3b) (crnko, 1990; crnko & vragović, 1990) and on the southern slopes of dilj mt. (fig. 3c) (šparica et al., 1980). so, the vb have similar lithological characteristics across the whole investigated area of the western part of lake slavonia. 3. methods 3.1. field methods a total of 51 samples were collected during the field research. in the area of vukomeričke gorice, detailed investigations of the vb were carried out at the lipnica, petravec, čakanec, strezojevo, kravarsko, ključić brdo, vukomerić and donji hruševec sites (fig. 3a). in addition, the underlying miocene sediments were sampled at bašića brdo and overlying quaternary sediments at the žažina and orleković sites (fig. 3a) to draw some conclusions regarding the compositional variability through the stratigraphic sequence. outside the area of vukomeričke gorice, the vb were sampled in the banovina region near the town of petrinja and the village of komarevo located south of vukomeričke gorice (fig. 3a). east of vukomeričke gorice, the vb were sampled on the southwestern slopes of psunj mt. near the village of subocka (fig. 3b) and near sibinj on the southern slopes of dilj mt. (fig. 3c). 3.2 laboratory methods laboratory analyses included chemical and mineralogical­petro­ graphic analyses of the sediments. the chemical analyses were carried out at the acme analytical laboratories ltd in van­ couver, canada, and all other analyses were performed at the laboratory of the croatian geological survey (hgi) in zagreb. the mineral and petrographic composition of the sandy­ gravelly sediments was determined using an optical microscope. the mineral composition of sands was determined for 37 samples in total by analysis of heavy (hmf) and light mineral fractions (lmf) ranging from 0.063 – 0.16 mm grain-size fraction. before separation, the carbonate component was dissolved (when pres­ ent) with 4% hcl. the separation was performed with bromo­ form (2.9 g/cm3). the qualitative and quantitative composition of both the lmf and hmf was determined by the ribbon counting method on at least 300 grains (>150 translucent grains), (mange & maurer, 1992). mineral grains from the lmf were grouped according to the method used by dickinson (1985). petro­ graphic thin sections were prepared on 9 samples of coarse sand and fine gravel from the fractions 0.90 – 1.25 mm and 1.25 – 2.80 mm respectively. the mineral composition of 8 pelitic sediment samples was determined by x-ray powder diffraction (xrpd) using a pana­ lytical x’pert pro mpd diffractometer with a pw 3018/00 pix­ cel detector. experimental conditions were: cukμ radiation, 45 kv, 40 ma, primary beam divergence 1/4°, continuous scanning (step 0.02°2θ/s). the analyses were recorded from random mounts of bulk samples and oriented mounts of the <2 µm fraction of the insoluble rock residue. preparation for the xrpd analyses included: grinding sam­ ples for bulk sample analysis, dissolution of the carbonate com­ ponent where present (only for clay mineral analysis), and sepa­ ration of the < 2 µm grain fraction using centrifuge methods described by krumm (1994). to remove the carbonates the sam­ ples were treated with a 1 m nh4ac solution buffered with hoac at ph 5 (jackson, 1956). g eologia c roatica 257kurečić et al.: mineral assemblage and provenance of the pliocene viviparus beds from the area of vukomeričke gorice, central croatia the determination of clay minerals on a fraction of <2 µm oriented mounts, was carried out according to the method of starkey et al (1984), which comprises: a) air drying, b) ethy­ lene glycol solvation, d) heating to 400°c and 550°c. the inter­ pretation of xrpd was performed using the calculation from high score plus (2008) and the databases pdf­4 / mine­ rals 4.5 (2016). the quantitative analysis was performed with the rockjock software and the method described by eberl (2003). preparation for quantitative analysis described by eberl (2003) included addition of internal standard zincite (0.111 g zno to 1 g sample) and grinding the mixture in a mccrone mill for 5 minutes with 4 ml methanol. ground samples were dried, sieved, well mixed, packed into a holder and then recorded from 5 to 65 °2θ using cu kα radiation, with step 0.02°2θ/s. chemical analyses of samples were performed in the ac­ melabs, a bureau veritas group company (www.acmelab.com) in vancouver (canada). chemical analyses were obtained on 24 sand samples and 10 pelitic sediment samples having had their carbonates previously dissolved. the major elements content was determined by inductively coupled plasma emission spectroscopy (icp­es), while trace elements were measured with an induc­ tively coupled plasma mass spectrometer (icp-ms). major and trace elements were analysed after melting of the samples with lithium metaborate (libo2), while precious and non­precious metals were analysed from a solution prepared by dissolving the samples in aqua regia (hno3+3 hcl). the accuracy and preci­ sion of the chemical data calculated based on internal standards (so­18, ds10, gs­311­1, gs910­4 and oresas45ea) and repe­ tition of analyses on three samples (str­ii 7/1, pet­i 1/1, cak­i 7/1) was satisfactory for all elements used in the provenance analyses (kurečić, 2017). 4. results 4.1. modal composition of sand 4.1.1. composition of lithic particles from coarse sand thin section analyses of the sand fraction > 0.9 mm in samples from different localities in the area of vukomeričke gorice showed that all sands consist of particles from older sedimentary rocks including quartzite, acidic to basic igneous rocks and meta­ sediments, but differ in the quantitative amount of the individual particle groups (fig. 4a). in the sands of the strezojevo locality, grains of radiolarites (fig. 4a, b, c) and quartzite (fig. 4a, d) pre­ dominate. radiolarite particles comprise up to 40% and quartzite about 20% of all particles. about 25% of the lithic fragments are igneous rocks, among them basalt­diabase (fig. 4a, e) and basalts are the most abundant, while andesite­basalts and andesites oc­ cur only sporadically. in the sample str­i 1/1, neutral igneous rocks are completely absent. among other particles, metasedi­ ments (metapsammite and rarely quartz-sericite schists), sand­ stone and individual quartz grains are relatively common. the str-i 5/1 sample also included a particle with microperthite veins characteristic of granite rocks (fig. 4f). in the same sample, the planktonic foraminifera globigerina sp. was also observed (fig. 4g). coarse-grained sandy and fine-grained gravelly detritus from the lipnica and ključić brdo locality contains less chert particles than the strezojevo locality (fig 4a). at the lipnica lo­ cality, the number of metasediments, mostly metapsammites (fig. 4h), is about 5% (fig 4a), while clasts of neutral­acid igne­ ous rocks are almost absent. furthermore, only chert­like parti­ cles were detected at the lipnica site (fig. 4i), with radiolarite absent. in addition, the detritus of the ključić brdo site is characterized by the highest proportion (up to 25%) of neutral-mafic igneous rocks (fig. 4a, 4j, 4k). the sand detritus of the petravec site is similar to the samples from the previously described sites, although with reduced quantities of individual groups. it is characterized by the almost complete absence of radiolarite particles (chert is present) and particles of neutral-mafic igneous rocks. an important feature that distinguishes the petravec site from all other sites is the occurrence of carbonate grains, comprise 50% of the detritus (fig 4a). these are dolomite grains and recrystal­ lized (fig. 4l) and partially recrystallized micrite limestones (fig. 4m). a carbonate particle composed of the fossil remains of red algae was also recorded. the sand at the orleković locality is similar in composition to the sand of the strezojevo, lipnica and ključić brdo localities, but contains a much smaller amount of radiolarite/chert particles followed by increased amounts of sandstone (mostly quartz areni te) particles (fig 4a). 4.1.2. heavy and light mineral composition of sand and sandy silt analyses of the finer sand fractions (0.063-0.16 mm) at all the in­ vestigated sites in the area of vukomeričke gorice, slavonia and banovina showed that there are no significant differences in the composition of the lmf of sand detritus of the vb depending on the sampling area (tab. 1). monocrystalline quartz grains with an average content of 76% predominate in all the samples. the grains are moderately rounded, with uniform or undulose extinc­ tion. among the rock particles, (average content of 18%), the most common types are chert, quartzite (qzp in table 1) and volcani­ clastic (tuff) particles. fragments of schists with a low degree of metamorphism have also been observed. feldspar is represented in the form of weathered potassium feldspar and averages about 6% in composition. mica (muscovite) occurs only sporadically in concentrations of less than 1% in the form of transparent thin plates with rounded edges. in the hmf, the quantity of which ranges between 0.6% and 9%, opaque minerals and translucent heavy minerals dominate, while the quantity of biotite and chlorite is generally below 1% (tab. 2). the average amount of opaque minerals is 63% (tab. 2). completely opaque black grains and reddish grains along the edges are observed. among the translucent heavy minerals, garnets are com­ monly found in most samples. their average content in the sam­ ples is about 34%. they are most abundant in the locality of pe­ travec, where their share reaches up to 60%. in the localities of žažina and orleković, garnets only sporadically occur, while they were not found at all in the locality of bašića brdo (tab. 2). regarding weathering stages, garnet grains range from unweathe­ red to slightly corroded. besides garnets, epidote and staurolite are also significantly represented. their share among the trans­ lucent heavy minerals is about 12% on average, in the ptr-1 sam­ ple it reaches 31% (tab. 2). staurolite was found in all samples except the kom­1 sample, and ranges from unweathered to slightly corroded grains, similar to epidote. the highest percenta ge (23%) occurs in the str­i 2/1 sample (tab. 2). the most resis­ tant translucent heavy minerals such as zircon, rutile and tour­ maline were found in all samples with an average content of between 6% and 9% (tab. 2). tourmaline occurs in the form of subrounded to angular, usually prismatic grains, with brown ple­ ochroism. rutile occurs in slightly rounded forms, often with a prismatic habit or occasionally as broken fragments. its colour is usually reddish­brown or dark red. zircons are usually short­ prismatic, and in most cases subrounded. crystal fragments or g eo lo gi a c ro at ic a 258 geologia croatica 74/3 euhedral zircon crystals are relatively rare. the largest amount of zircon occurs in the quaternary sediment from the žažina site, where their concentration reaches up to 27% (tab. 2). other translucent heavy minerals are found only in very small percent­ ages (tab. 2). kyanite, for example, is present in most of the an­ alysed samples, but its content does not exceed 5%, except at the sibinj site. amphiboles were found in all samples, but their av­ erage content was only about 6%. they are available in greenishblue to green varieties, or colourless, angular to subrounded, slight corroded grains. pyroxenes occur only in some samples with the amount of less than 3%, except at the sibinj site where they contribute up to 8% of the composition of the translucent figure 4. petrographic composition of coarse-grained sand of the viviparus beds from the area of vukomeričke gorice: a) pie charts showing the composition of the grain fraction with particle diameters between 0.25 mm and 0.9 mm. photomicrographs of lithic particles: b) radiolarite from the sample str-i 5/1, (a-); c) radiolarite from the sample str-i 5/1, (a +); d) quartzite from sample str-i 5/1, (a +); e) diabase from sample str-i 5/1, (a-); f ) microperthite growth from sample str-i 5/1, (a +); g) globigerina sp. from sample str-i 5/1, (a-); h) metapsammite from sample lip-i 21/1, (a-); i) chert from sample lip-i 21/1, (a +); j) andesite-basalt from sample kbr-i, (a-); k) basaltdiabase from sample kbr-i, (a-); l) recrystallized limestone from sample pet-i 10/2, (a-); m) partially recrystallized micrite limestone from sample pet-i 10/2, (a-). legend: (a-) – photographed without included analyzer; (a+) – photographed with the included analyzer. g eologia c roatica 259kurečić et al.: mineral assemblage and provenance of the pliocene viviparus beds from the area of vukomeričke gorice, central croatia minerals of the hmf (tab. 2). they occur in green and colour­ less varieties with vivid interference colours and correspond to the hypersthene in their optical properties. regarding weather­ ing of unresistant heavy minerals, pyroxene shows a higher de­ gree of weathering than amphiboles. therefore, the degree of pyroxene alteration could be roughly estimated on c1, e2, and d2 classes (according to andò et al., 2012). minerals such as zoi­ site/clinozoisite, titanite, cr-spinel and brookite/anatase have only rarely been recorded (tab. 2). 4.1.3. modal composition of the pelitic sediments the main mineral constituents of the pelitic sediments of all the analysed samples are clay minerals and quartz, while the content of other mineral species (calcite, dolomite and minerals from the feldspar group) varies from sample to sample (tab. 3; fig. 5a). among the clay minerals determined from oriented samples of the <2 µm grain fraction, the most common are smectite and il­ lite/muscovite, while a small amount of kaolinite is present in all samples. chlorite occurs only in samples kra-i 5/1 and vuk-i 7/1, table 1. modal composition of the light mineral fraction (0.09-0.16 mm) of the viviparus beds from the vukomeričke gorice, banovina and slavonia and the surrounding underlying and overlying deposits with detrital modes according to dickinson (1985) in %. qzm=monocrystalline quartz; qzp=polycrystalline quartz; qzt=qzm+qzp; l=other lithic particles; lt=qzp+l, kfs=potassium feldspar; pl=plagioclase; ms=muscovite. area locality sample lithology qzm qzp qzt l lt kfs pl ms vukomeričke gorice lipnica lip-i 5/1 sand 61 14 75 19 33 6 + – lip-i 22/1 sand 57 11 68 29 40 3 – – lip-i 28/1 silty sand 59 7 66 24 31 10 – – strezojevo str-i 1/1 clayey sand 83 5 88 9 14 2 – – str-i 2/1 sand 75 5 80 14 19 6 – – str-i 5/1 silty-gravelly sand 85 4 89 7 11 4 – – str-ii 3/1 silty sand 91 5 96 3 8 1 – – str-ii 5/1 silty-gravelly sand 87 5 92 4 9 4 – – str-ii 5/1c sand 74 8 82 10 18 8 – – str-ii 7/1 sand 70 5 75 14 19 11 – – ključić brdo kbr-i 1/1 sand 74 10 84 10 20 5 – – kbr-i 11/1 sand 62 20 82 9 29 9 – – vukomerić vuk-i 1/1 silty sand 77 6 83 9 15 8 + – vuk-i 5/1 sandy silt 61 7 68 22 29 10 1 – vuk-i 5/2 silty sand 71 6 77 15 21 8 – + vuk-i 10/1 silty sand 63 4 67 22 26 11 – 1 petravec pet-i 1/1 sand 73 9 82 12 21 6 – – pet-i 2/1 sand 75 6 81 9 15 9 – – pet-i 9/1 sand 67 11 78 14 25 9 – – pet-i 10/2 silty sand 73 9 82 15 24 4 – – čakanec cak-i 7/1 sand 75 2 77 16 18 7 – – cak-i 11/1 silt 80 3 83 8 11 9 – – cak-i 17/1 silty sand 68 6 74 13 19 13 – + cak-i 24/1 sandy silt 74 6 80 11 17 8 – – cak-i b2 sand 73 3 76 14 17 10 – – donji hruševec dhr-i 1/1 sand 78 7 85 8 15 8 – – žažina zaz-1 silty sand 84 5 89 6 11 5 – – zaz-2 clayey silt 87 4 91 7 11 2 – – orleković orl-1 silty sand 77 4 81 13 17 5 – – bašića brdo bbr-1 silty sand 90 4 94 5 9 1 – – bbr-2 sandy-silty clay 93 4 97 3 7 – – – slavonija sibinj sib-i 1/1 silty sand 82 8 90 9 17 2 – – sib-i 5/1 silty sand 87 7 94 4 11 3 – – subocka sub-i 2/1 silty sand 79 11 90 5 16 5 – + sub-i 9/1 silty sand 89 1 90 2 3 8 – + banovina petrinja ptr-1 silty sand 57 18 75 21 39 4 – + komarevo kom-1 sandy-silty gravel 78 14 92 3 17 4 – + g eo lo gi a c ro at ic a 260 geologia croatica 74/3 ta bl e 2. m od al c om po si tio n of th e he av y m in er al fr ac tio n (0 .0 90. 16 m m ) o f t he v iv ip ar us b ed s f ro m th e vu ko m er ič ke g or ic e, b an ov in a an d sl av on ia to ge th er w ith th e su rr ou nd in g un de rly in g an d ov er ly in g de po si ts . o pq – o pa qu e m in er al s, bt – b io tit e, c hl – c hl or ite , t h m – t ra ns lu ce nt h ea vy m in er al s, tu r – to ur m al in e, z rn – z irc on , r t – ru til e, p x – py ro xe ne , a m p – am ph ib ol e, e p – ep id ot e; z ocz o – zo is ite , c lin oz oi si te , g rt – g ar ne t, ky ky an ite , s t – s ta ur ol ite , t tn – ti ta ni te , s pn – c rsp in el , b rk /a nt – b ro ok ite /a na ta se , o th . – m in er al g ra in s w hi ch w er e no t p os si bl e to d et er m in e. a re a lo ca lit y sa m pl e h m f (% ) tr an sl uc en t h ea vy m in er al s ( % ) o pq bt ch l th m tu r zr n rt px a m p ep zo -c zo g rt ky st tt n sp n br k/ a nt o th . vu ko m er ič ke go ric e li pn ic a li pi 5 /1 52 – – 48 4 4 4 3 5 12 1 56 2 5 4 li pi 2 2/ 1 44 – – 56 5 1 3 2 4 9 63 1 8 1 3 li pi 2 8/ 1 60 + + 39 4 2 3 14 17 5 41 2 7 5 st re zo je vo st ri 1 /1 78 – – 22 24 17 12 1 1 18 1 1 2 21 2 st ri 2 /1 81 + – 19 12 11 11 2 12 14 4 2 4 23 5 st ri 5 /1 80 – – 20 12 25 16 12 5 13 11 1 5 st rii 3/ 1 78 – – 22 24 10 7 10 8 3 6 1 21 6 4 st rii 5/ 1 71 – – 29 6 16 8 2 8 3 39 1 12 2 3 st rii 5/ 1c 78 – – 22 9 9 6 12 9 32 1 18 4 st rii 7/ 1 56 – – 44 4 6 6 10 11 52 1 7 1 2 kl ju či ć br do kb ri 1 /1 50 – 1 49 3 6 7 2 4 10 1 59 3 2 3 kb ri 1 1/ 1 54 – 1 45 8 7 4 1 4 25 1 35 1 11 3 vu ko m er ić vu ki 1 /1 58 – – 42 5 12 9 4 7 43 3 15 1 1 vu ki 5 /1 61 – 1 38 9 6 6 1 3 13 2 44 3 10 3 vu ki 5 /2 58 – – 42 3 5 11 2 10 1 51 2 12 3 vu ki 1 0/ 1 59 – + 41 8 6 10 4 6 48 4 11 3 pe tr av ec pe ti 1 /1 41 – – 59 3 2 2 3 6 10 4 60 1 7 2 pe ti 2 /1 50 – – 50 6 3 4 3 6 14 2 42 1 13 6 pe ti 9 /1 72 – – 28 2 3 3 2 4 11 1 56 16 2 pe ti 1 0/ 2 59 – – 41 3 6 7 3 5 11 4 52 1 6 2 ča ka ne c ca ki 7 /1 52 – – 48 9 2 4 2 8 1 49 1 20 4 ca ki 1 1/ 1 65 – + 35 5 13 12 2 2 1 48 2 11 2 2 ca ki 1 7/ 1 60 – + 40 9 9 7 3 11 4 41 1 12 3 ca ki 2 4/ 1 64 – 1 34 8 6 3 3 2 8 2 46 2 15 1 4 ca ki b 2 63 – + 36 8 4 9 14 37 1 22 1 4 d on ji h ru še ve c d h ri 1 /1 60 – – 40 5 5 5 7 11 38 3 23 1 1 1 ža ži na za z1 77 – – 23 15 18 4 7 21 5 10 15 1 4 za z2 74 – – 26 9 27 10 12 9 1 10 14 5 3 o rle ko vi ć o rl1 67 – – 33 16 1 8 2 13 13 4 6 5 27 1 4 ba ši ća b rd o bb r1 83 – – 17 19 13 14 11 6 1 13 19 4 bb r2 85 – – 15 26 11 11 14 3 1 9 3 19 3 sl av on ija si bi nj si bi 1 /1 28 – – 71 10 1 5 8 6 23 1 24 13 5 2 1 1 si bi 5 /1 33 – – 67 9 2 8 3 7 19 1 33 8 7 3 su bo ck a su bi 2 /1 43 – – 57 15 6 6 6 11 9 3 31 2 8 3 su bi 9 /1 51 – – 49 7 9 14 1 6 8 1 43 1 6 4 ba no vi na pe tr in ja pt r1 89 + 3 8 10 2 4 3 31 6 28 2 6 3 5 ko m ar ev o ko m -1 85 – 3 13 28 12 9 4 16 2 18 8 3 g eologia c roatica 261kurečić et al.: mineral assemblage and provenance of the pliocene viviparus beds from the area of vukomeričke gorice, central croatia while in sample sub­i 8/1 its occurrence is uncertain. (fig. 5b). namely, chlorite has a diffraction maximum at a similar position (7 å) to kaolinite, and the problem with determination occurs when it is present in small quantities. 4.2. chemical composition of sediments the results of the chemical analysis of the major and trace ele­ ments are shown in tables 4 and 5. chemical analysis showed that the vb consist mostly of sio2 (53.83–90,95 %), al2o3 (3.81– table 3. quantitative mineral composition of bulk sample and semi-quantitative mineral composition of the <2 µm fraction of pelitic viviparus beds samples from vukomeričke gorice and slavonia, obtained by xrpd and rock jock software (eberl, 2003). the quantitative composition is given in weight %. **** dominant (60-100%), *** abundant (30-60%), ** considerable (10-30%), *minor (1-10%), + traces (< 1%). locality strezojevo ključić brdo kravarsko kravarsko čakanec vukomerić sibinj subocka sample str-ii 2/1 kbr-i 8/1 kra-i 1/1 kra-i 5/1 cak-i 11/1 vuk-i 7/1 sib-i 5/2 sub-i 8/1 quartz 16 12 16 14 21 8 14 21 calcite 4 6 8 8 9 7 dolomite 9 7 8 6 plagioclase + 6 3 13 + k feldspar + + clays total 80 88 63 68 51 75 79 79 semi-quantitative mineral composition of the < 2 µm fraction smectite *** **** *** ** *** *** *** *** illite/muscovite *** ** ** * ** * ** ** kaolinite * * * * * * * * chlorite ** ** +? figure 5. example for: a) xrpd patterns of the whole sample of pelitic sediment cak-i 11/1 from the čakanec locality in vukomeričke gorice and sample sib-i 5/2 from sibinj in slavonia, showing that they consist of quartz, calcite, dolomite, smectite, kaolinite, illite, potassium feldspar and plagioclase; b) xrd patterns of the <2 µm fraction of sample vuk-i 7/1 from vukomerić in vukomeričke gorice, taken after the following treatments: air-dried sample; sample treated with ethylene glycol; sample heated to 400°c; sample heated to 550°c. the results obtained show that smectite, illite, kaolinite and chlorite are present in the clay mineral composition. legend: s – smectite; kln – kaolinite; ill – illite; qz – quartz; pl – plagioclase; kfs – potassium feldspar; cal – calcite; dol – dolomite. g eo lo gi a c ro at ic a 262 geologia croatica 74/3 ta bl e 4. m aj or e le m en ts (% b y w ei gh t) co m po si tio n of b ul k se di m en ts (s an ds a nd p el iti c se di m en ts ) a nd in so lu bl e ro ck re si du e (* ) f ro m v uk om er ič ke g or ic e. c ia ch em ic al in de x of a lte ra tio n, (n es bi t & yo u n g , 1 98 2) a nd ic v i nd ex o f co m po si tio na l v ar ia bi lit y (c o x et a l., 1 99 5) . l o i lo ss o n ig ni tio n. p el iti c se di m en ts a re m ar ke d by it al ic s. lo ca lit y sa m pl e si o 2 a l 2o 3 fe 2o 3 m go ca o n a 2 o k 2 o ti o 2 p 2 o 5 m no lo i su m ci a ic v si o 2/ k 2 o / a l 2o 3 a l 2o 3 li pn ic a li pi 5 /1 * 80 .4 0 7. 68 2. 05 1. 30 1. 33 0. 81 1. 52 0. 43 0. 07 0. 01 4. 30 99 .9 3 58 .7 3 1. 37 10 .4 7 0. 20 li pi 1 0/ 1* 83 .4 8 6. 93 1. 86 0. 85 0. 78 0. 80 1. 42 0. 34 0. 06 0. 01 3. 40 99 .9 5 61 .8 7 1. 16 12 .0 5 0. 20 li pi 2 7/ 2* 62 .3 1 15 .2 5 6. 14 2. 04 1. 46 0. 75 2. 66 0. 79 0. 10 0. 12 8. 20 99 .8 3 69 .2 6 1. 12 4. 09 0. 17 li pi 2 8/ 1* 73 .9 9 10 .2 4 2. 82 1. 71 1. 66 0. 94 1. 87 0. 66 0. 07 0. 02 5. 90 99 .8 7 60 .8 5 1. 33 7. 23 0. 18 st re zo je vo st ri 1 /1 74 .6 3 11 .3 9 4. 80 0. 58 0. 04 0. 27 1. 28 0. 44 0. 08 0. 06 6. 30 99 .9 0 85 .6 9. 0. 62 6. 55 0. 11 st ri 1 /2 76 .7 8 10 .2 3 4. 36 0. 52 0. 04 0. 25 1. 16 0. 40 0. 07 0. 07 6. 00 99 .9 2 85 .4 7 0. 63 7. 51 0. 11 st ri 2 /1 88 .6 6 5. 43 1. 48 0. 29 0. 06 0. 49 1. 21 0. 23 0. 03 0. 01 2. 10 99 .9 7 70 .9 3 0. 78 16 .3 3 0. 22 st ri 4 /1 68 .4 7 13 .9 1 5. 63 0. 90 0. 03 0. 18 2. 13 0. 98 0. 05 0. 02 7. 50 99 .8 5 83 .9 7 0. 71 4. 92 0. 15 st rii 2/ 1* 62 .0 9 18 .1 2 3. 97 1. 66 0. 61 0. 57 3. 04 0. 83 0. 08 0. 03 8. 80 99 .8 4 77 .2 5 0. 73 3. 43 0. 17 st rii 3/ 1 86 .3 6 6. 55 1. 28 0. 43 0. 20 0. 17 1. 08 0. 78 0. 03 0. 02 2. 90 99 .8 9 78 .3 3 0. 72 13 .1 8 0. 16 st rii 5/ 1 88 .9 6 4. 00 1. 73 0. 25 0. 31 0. 47 0. 84 0. 18 0. 05 1. 05 2. 10 99 .9 4 64 .0 4 1. 43 22 .2 4 0. 21 st rii 7/ 1 84 .3 1 6. 98 2. 53 0. 50 0. 31 0. 80 1. 37 0. 39 0. 07 0. 06 2. 60 99 .9 5 67 .4 9 0. 98 12 .0 8 0. 20 kl ju či ć br do kb ri 1 /1 84 .2 1 7. 81 1. 66 0. 53 0. 29 0. 77 1. 55 0. 45 0. 06 0. 02 2. 60 99 .9 4 69 .2 3 0. 83 10 .7 8 0. 20 kb ri 7 /1 71 .1 2 13 .6 8 3. 96 1. 00 0. 36 0. 76 2. 24 0. 78 0. 07 0. 05 5. 80 99 .8 5 75 .9 6. 0. 76 5. 20 0. 16 kb ri 8 /1 57 .1 4 19 .6 9 5. 55 1. 72 0. 67 0. 39 2. 69 0. 84 0. 06 0. 05 11 .0 0 99 .8 2 80 .4 9 0. 70 2. 90 0. 14 kb ri 1 1/ 1 78 .5 8 10 .2 2 2. 94 0. 83 0. 22 0. 90 1. 96 0. 50 0. 04 0. 03 3. 70 99 .9 1 71 .8 6 0. 85 7. 69 0. 19 vu ko m er ić vu ki 1 /1 * 78 .9 5 9. 70 2. 89 0. 78 0. 38 0. 93 1. 84 0. 61 0. 08 0. 03 3. 70 99 .9 1 69 .2 7 0. 91 8. 14 0. 19 vu ki 7 /1 * 53 .8 3 20 .7 8 2. 58 3. 39 2. 68 0. 65 3. 87 0. 80 0. 06 0. 03 11 .1 0 99 .8 0 67 .2 2 1. 03 2. 59 0. 19 vu ki 5 /2 * 75 .1 4 10 .8 8 3. 38 0. 88 0. 44 0. 97 1. 98 0. 68 0. 09 0. 04 5. 40 99 .8 8 70 .5 6 0. 91 6. 91 0. 18 vu ki 1 0/ 1* 73 .6 5 11 .3 9 3. 81 1. 09 0. 72 0. 92 1. 98 0. 71 0. 14 0. 05 5. 40 99 .8 8 69 .6 4 0. 98 6. 47 0. 17 pe tr av ec pe ti 1 /1 87 .5 6 5. 80 1. 99 0. 37 0. 28 0. 71 1. 21 0. 31 0. 05 0. 05 1. 60 99 .9 5 66 .0 1 0. 98 15 .1 0 0. 21 pe ti 2 /1 * 86 .5 0 5. 88 2. 22 0. 35 0. 23 0. 80 1. 28 0. 28 0. 07 0. 03 2. 30 99 .9 6 65 .3 3 0. 99 14 .7 1 0. 22 pe ti 9 /1 * 90 .9 5 3. 81 1. 72 0. 18 0. 18 0. 63 0. 96 0. 17 0. 05 0. 03 1. 30 99 .9 7 61 .3 2 1. 11 23 .8 7 0. 25 pe ti 1 0/ 2* 77 .2 2 7. 92 6. 47 0. 51 0. 46 0. 61 1. 42 0. 42 0. 10 0. 30 4. 50 99 .9 3 70 .1 1 1. 23 9. 75 0. 18 ča ka ne c ca ki 7 /1 * 83 .2 4 8. 27 1. 87 0. 60 0. 28 0. 90 1. 64 0. 55 0. 06 0. 02 2. 50 99 .9 3 68 .7 2 0. 87 10 .0 7 0. 20 ca ki 1 1/ 1* 69 .2 7 14 .1 9 3. 78 1. 50 0. 83 0. 83 2. 45 0. 78 0. 09 0. 06 6. 10 99 .8 6 71 .9 7 0. 90 4. 88 0. 17 ca ki 1 7/ 1* 78 .6 1 10 .4 6 2. 45 0. 84 0. 41 0. 97 1. 97 0. 66 0. 09 0. 04 3. 40 99 .9 0 70 .0 4 0. 87 7. 52 0. 19 ca ki 2 4/ 1* 70 .0 1 12 .7 6 3. 16 1. 78 1. 53 0. 87 2. 24 0. 74 0. 09 0. 04 6. 60 99 .8 7 65 .7 8 1. 11 5. 49 0. 18 kr av ar sk o kr ai 1 /1 * 63 .2 7 17 .2 7 4. 56 1. 69 0. 76 0. 70 2. 97 0. 91 0. 11 0. 09 7. 50 99 .8 3 75 .0 3 0. 82 3. 66 0. 17 kr ai 5 /1 * 59 .1 6 18 .5 4 3. 52 2. 38 1. 76 0. 56 3. 20 0. 90 0. 11 0. 02 9. 70 99 .8 3 70 .9 7 0. 92 3. 19 0. 17 kr ai 6 /1 * 59 .2 2 18 .3 7 4. 88 1. 97 1. 54 0. 51 2. 58 0. 91 0. 09 0. 23 9. 50 99 .8 2 74 .0 7 0. 87 3. 22 0. 14 kr ai 7 /1 * 59 .0 9 19 .2 8 4. 48 1. 53 0. 88 0. 49 2. 57 0. 85 0. 06 0. 03 10 .5 0 99 .8 3 78 .8 0 0. 68 3. 06 0. 13 o rle ko vi ć o rl1 81 .7 7 8. 80 2. 42 0. 60 0. 20 0. 79 1. 73 0. 51 0. 04 0. 04 3. 00 99 .9 2 71 .3 4 0. 83 9. 29 0. 20 ba ši ća b rd o bb r1 84 .1 1 6. 92 2. 63 0. 39 0. 15 0. 21 1. 07 0. 80 0. 04 0. 06 3. 50 99 .8 9 79 .5 7 0. 80 12 .1 5 0. 15 g eologia c roatica 263kurečić et al.: mineral assemblage and provenance of the pliocene viviparus beds from the area of vukomeričke gorice, central croatia 20.78 %) and minor contents of fe2o3 (1.28–6.47 %), k2o (0.84– 3.87 %), mgo (0.25–2.38 %), cao (0.04–2.68 %), tio2 (0.18–0.98 %), na2o (0.17­0.97 %), mno (0.01­1.05 %) and p2o5 (0.04­0.14 %). in addition, table 4 shows the data on the calculated values of the chemical index of alteration (cia = [al2o3/ (al2o3+cao*+na2o+k2o)]x100, cao* is the amount of cao only in silicate minerals) (nesbit & young, 1982) & index of compositional variability (icv=(fe2o3+k2o+na2o+cao+ mgo+mno+tio2)/al2o3) (cox et al., 1995). the cia for sandy samples varies from 58.73–85.69, and 67.22–83.97 for pelitic sedi ments. the icv for sandy samples varies from 0.62–1.37, while for pelitic sediments it is 0.68–1.16. 5. discussion 5.1. modal composition and origin of the detritus 5.1.1. composition of sand analyses of the modal composition of the sandy detritus of the vb from the area of vukomeričke gorice showed that it was formed by the erosion of various magmatic, metamorphic and sedimentary rocks (fig. 4; tab. 1, tab. 2). among the magmatic rocks, basic ones were the most common in source rock compo­ sition and, to a lesser extent, neutral and acidic rocks. these rocks have been identified as a component of the palaeogene conglomerates and sandstones from banovina (šebečić, 1971; majer, 1983; pikija, 1987a), which crop out on the surface southeast of vukomeričke gorice in the area of banovina (hgi, 2009) (fig. 2). fragments of basic igneous rocks could have originated from upper cretaceous-palaeogene basic effusions, which occur on the surface very close to the vukomeričke gorice area on the southern bank of the kupa river (hgi, 2009), or from an ophio­ lite melange, as occurs today on the surface of medvednica mt. (halamić et al., 1999; goričan et al., 2005; lugović et al., 2007; lužar-oberiter et al., 2009; slovenec & šegvić, 2019) (fig. 2). alternatively, fragments of the acid igneous rocks, apart from the palaeogene clasts of banovina, could have originated directly from the granite complex of moslavačka gora (crnko, 1990; crnko & vragović, 1990, hgi, 2009; starijaš et al., 2010). particles of metasedimentary rocks could have originated from palaeozoic metamorphic rocks that crop out north of the study area of vukomeričke gorice on medvednica mt. (belak et al., 1995; hgi, 2009; mišur, 2017). they also might have been derived from the upper palaeozoic metasedimentary rocks of petrova gora and trgovska gora in banovina (šikić et al., 1978; šikić et al., 1990a; šikić et al., 1990b; belak et al., 1995; hgi, 2009; mišur, 2017). carbonate table 5. composition of trace elements (ppm) and their ratios of bulk sediments (sands and pelitic sediments) and insoluble rock residue (*) from vukomeričke gorice. pelitic sediments are marked by italics. locality sample th sc la zr nb y tio2 zr/tio2 nb/y lipnica lip-i 5/1* 5.7 6 15.7 112.8 6.4 13.5 4300 0.026 0.474 lip-i 10/1* 5.6 5 13.8 105.1 4.9 12.8 3400 0.031 0.383 lip-i 27/2* 12.3 15 32.4 218 13.3 31.5 7900 0.028 0.422 lip-i 28/1* 8.8 8 18.4 252.8 10.5 14.7 6600 0.038 0.714 strezojevo str-i 1/1 8.8 10 29 104.2 7.1 27 4400 0.024 0.263 str-i 1/2 8 9 25.9 98.3 6.3 25.2 4000 0.025 0.25 str-i 2/1* 4.8 3 10.8 86.3 3.7 10.4 2300 0.038 0.356 str-i 4/1 11.8 16 35.9 313.6 15.2 35.8 9800 0.032 0.425 str-ii 2/1* 13 16 32.3 191.9 13.6 23.5 8300 0.023 0.579 str-ii 3/1 7.7 6 21 466 11.3 20.7 7800 0.059 0.546 str-ii 5/1 4 3 18.5 70.9 2.7 13.4 1800 0.039 0.201 str-ii 7/1 5.7 5 15.1 114.5 5.7 12.1 3900 0.029 0.471 ključić brdo kbr-i 1/1 7.3 6 31.6 153.3 6.6 28.1 4500 0.034 0.235 kbr-i 7/1 11.5 12 39.1 287.1 11.6 32.4 7800 0.037 0.358 kbr-i 8/1 14.7 17 23.6 168.5 13.3 22.1 8400 0.02 0.602 kbr-i 11/1 8 8 23 129.5 8 22.5 5000 0.026 0.356 vukomerić vuk-i 1/1* 7.5 7 21.4 191.3 10 18.1 6100 0.031 0.552 vuk-i 7/1* 16.3 14 41 180.5 15.4 24.6 8000 0.023 0.626 vuk-i 5/2* 8.7 8 22.4 227.8 11 19.8 6800 0.034 0.556 vuk-i 10/1* 9.6 9 26.2 271.7 12.1 22.2 7100 0.038 0.545 petravec pet-i 1/1 5.4 4 16.6 108.7 4.9 13.1 3100 0.035 0.374 pet-i 2/1* 4.5 4 11.4 86.6 4.3 11.7 2800 0.031 0.368 pet-i 9/1* 3.6 2 9.8 66.8 2.6 8.6 1700 0.039 0.302 pet-i 10/2* 7 7 20.5 139 6.8 21 4200 0.033 0.324 čakanec cak-i 7/1* 6.5 6 28.6 144.6 9.1 24.5 5500 0.026 0.371 cak-i 11/1* 10.5 12 22 249.3 13.4 18.3 7800 0.032 0.732 cak-i 17/1* 8.1 8 25.4 207.5 10.3 20.3 6600 0.031 0.507 cak-i 24/1* 9.9 10 20.3 253.7 11.3 14.2 7400 0.034 0.796 kravarsko kra-i 1/1* 13.4 15 35.5 225.1 15 27.3 9100 0.025 0.549 kra-i 5/1* 14.6 16 38.1 203.5 14.8 26.9 9000 0.023 0.55 kra-i 6/1* 14 16 37.2 203.1 15.5 26.5 9100 0.022 0.585 kra-i 7/1* 13.6 18 35.3 178.1 13.9 25 8500 0.021 0.556 orleković orl-1 7.5 7 25.4 148 7.6 24.5 5100 0.029 0.31 bašića brdo bbr-1 9.1 7 20.5 389.3 13.6 16.8 8000 0.049 0.81 g eo lo gi a c ro at ic a 264 geologia croatica 74/3 detritus possibly originated from the older triassic carbonate rocks. thus, the lithic fragments of recrystallized micrite lime­ stones resemble the early triassic limestones found in the sur­ rounding areas of žumberak mt., banovina and medvednica mt., while the dolomite particles originate from the dolomites of the middle and upper triassic, which occur in the same areas (šikić et al., 1978; šikić et al., 1990; hgi, 2009). the radiolarite frag­ ments that appear together with the lithic carbonate fragments do not have the microphysiographic characteristics of the radiola­ rites of žumberak mt., so they are assumed to be transported from the banovina and/or medvednica mt. areas (goričan et al., 2005; halamić et al., 1999). the rounded lithic chert fragments could probably have undergone several phases of redeposition. the composition of the hmf, in which garnets predominate among the translucent heavy minerals, with abundant minerals from the epidote group, and also with regularly present amphi­ boles (tab. 2), indicates that a significant part of the detritus was redeposited from the early miocene sediments. such a mineral composition is characteristic for the upper miocene sediments, which form a large part of the infilling of the ncb. on the sur­ face, they occur on the edges of mountains in the north­western part of croatia and in the banovina region (šimunić & šimunić, 1987; kovačić et al., 2004; kovačić & grizelj, 2006; hgi, 2009). the absence of garnets in heavy mineral as­ sociations from the upper miocene was recorded at the bašića brdo site in the area of vukomeričke gorice (fig. 2). this is characteristic of the youngest upper miocene sediments and was pre­ viously recorded in the north-western part of ncb in the area of hrvatsko zagorje (kovačić & grizelj, 2006). the signifi­ cant occurrence of cr­spinel in the sands of the same locality has not yet been recorded in the upper miocene sands of the ncb. this important fact could possibly be related to the upper creta­ ceous-palaeogene source rocks from the area of banovina and the medvednica or žumberak mts. (fig. 3). in these deposits, lužar oberiter et al. (2019) identified the occurrence of crspinel. the dominance of the chemically most resistant particles, such as quartz, quartzite and chert (occasionally well-rounded particles) support the interpretation that a significant part of the sand detritus in the vb originates from older sedimentary or metasedimentary rocks, i.e., that it has undergone more than one depositional cycle (tab. 1; fig. 4a-4c, 4h). the fact that relatively unstable carbonate lithic fragments were preserved together with the predominant siliciclastic detritus indicates a weak influence of modifying factors, which together with poor sediment sorting (kurečić, 2017) indicates a short transport distance, i.e., the local origin of the material. the uniform composition of the sand detritus in the entire study area and also in the vertical sequence of deposits indicates that there were no significant changes in the source area during the deposition of the vb in the area of vukomeričke gorice. some significant compositional characteristics such as the high amount of garnets in the samples from the strezojevo site (tab. 2), are most likely due to the more or less large influence of local sources or are the result of the influence of modifying factors. these differences did not allow us to sepa­ rate the lower from the upper vb regarding mineral composition. the same conclusion was reached by pikija (1987a), who did not detect any regularity in the lateral or vertical arrangement of the mineral groups within the vb. in contrast, the quaternary sediments from the margins of the vukomeričke gorice area con­ tain an increased amount of well­rounded zircon and tourmaline grains compared to the mineralogical composition of the vb. the composition of the investigated quaternary samples can be re­ lated to the composition of the sediment of the kupa river, which was determined upstream of the vukomeričke gorice (kast­ müller, 2005). therefore, it seems likely that the mineralogi­ cal composition of the vb can be differentiated from quaternary sediments. 5.1.2. composition of pelitic sediments the pelites from the investigated vb consist mainly of quartz and clay minerals, in some cases they also contain carbonate mine rals and feldspar (tab. 3). quartz, feldspar and carbonate minerals are of detrital origin and are present in the coarser frac­ tions too. pliocene pelitic sediments have a similar clay mineral composition as the upper miocene marly sediments (grizelj et al., 2017). the appearance of smectite is usually associated with increased volcanic activity in the sedimentary area (chamley, 1989), however there is no other evidence of such an event in the studied sediments, nor has such activity been observed in the pliocene deposits of the ncb. therefore, the origin of smectite, the most abundant clay mineral in the analysed samples (tab. 3; fig. 5b), is probably related to the reworking of older sediments or volcanic material from older formations. the origin of illite/ muscovite, the second most common clay mineral, is most likely related to the weathering of schist and metapsammite or metapsammitic rocks which was determined by the analysis of lithic fragments and the lmf. namely, illite/muscovite and chlo­ rite represent the typical terrigenous mineral species, which were formed directly from eroded intrusive and metamorphic rocks (chamley, 1989). the presence of chlorite in only a few sam­ ples as part of the clay mineral composition of pelitic sediments and the hmf of the silty­sandy fraction, could be an indicator of more intensive chemical weathering of the sediments to which this mineral is poorly resistant (chamly, 1989; weaver, 1989). kaolinite is present in all samples in small quantities. it forms from feldspars and micas in areas when precipitation is relatively high and where there was good drainage to ensure the leaching of cations (mitchell & soga, 2005). the studied sediments indicate a relatively warm and humid climate, as was the case during the cernikian (mandic et al., 2015). neverthe­ less, the composition of clay minerals in lake environments is mainly a reflection of the composition of the source area (weaver, 1989). 5.1.3. origin of the detritus considering the physiographic or mineralogical features of the detritus, it can be concluded that the main sources of the sand de­ tritus of the vb from vukomeričke gorice were the nearby areas of the medvednica and žumberak mts and to a lesser extent moslavačka gora mt. the composition of the detritus indicates that part of the material most likely originated from the banovina region, primarily from the cretaceous­palaeogene clastics. the results obtained support the hypothesis of extension of the plio­ cene lake slavonia (neubauer et al., 2015; mandic et al., 2015), according to which the investigated area of vukomeričke gorice represents the north­western edge of the lake. this means that most of the detritus from the southern sources was deposited further south and east of the studied area (fig. 1). the inner di­ narides of bosnia and banovina might represent such southern source areas. the contribution of the southern sources was re­ corded in the detritus of the vb in slavonia. the occurrence of pyroxene and cr­spinel from bosnia, (at the sibinj site), indicate the south-north direction of palaeotransport (kovačić et al., g eologia c roatica 265kurečić et al.: mineral assemblage and provenance of the pliocene viviparus beds from the area of vukomeričke gorice, central croatia 2011) (tab. 2). the increased content of pyroxene and/or cr­spinel was also observed at the komarevo and petrinja sites in the ba­ novina area (tab. 2), so it additionally documents the south-north direction of palaeotransport or a nearly local origin (within ba­ novina area). the obtained results on the local origin of the detritus de­ posited in the ncb area during the pliocene indicate that a major change occurred regarding the source area during the transition from the miocene to the pliocene. indeed, during the late mio­ cene, detritus of a uniform modal composition was deposited throughout the ncb area, which was derived from the alps and the western carpathians (kovačić & grizelj, 2006; šimunić & šimunić, 1987; grizelj et al., 2017). such a change is most likely caused by basin inversion, which started in the sw part of the pbs at the end of the miocene and was inten­ sified in the pliocene and quaternary (tomljenović & csontos, 2001; pavelić, 2001; van gelder et al., 2015). compression uplifted individual blocks along the basin rim or figure 6. cross-plots of major oxides (wt. %) against al2o3 (wt. %) showing their correlations for sandy and pelitic viviparus beds samples from the area of vukomeričke gorice. data from table 4. g eo lo gi a c ro at ic a 266 geologia croatica 74/3geologia croatica 74/2 within the basin, and their erosion resulted in the locally influ­ enced detritus composition of the sediments deposited in the sur­ rounding depressions of the ncb. 5.2. chemical composition and origin of the detritus the relationship between chemical and mineral composition is shown using correlation diagrams in fig 6. it can be seen that sio2 has strong negative correlation with al2o3 (fig 6a), which can be interpreted as much of the sio2 being represented by quartz and chert grains. therefore, a further correlation was mainly made with al2o3 which represents the association of cer­ tain elements within clay minerals. with the exception of na2o (fig 6b) the other oxides and loi (loss on ignition) shown in the fig. 6 have a positive correlation with al2o3. positive correlation of k2o with al2o3 (fig 6c) reflects its presence in micaceous minerals and k­feldspar, while cao, mgo, tio2 and fe2o3 (fig. 6d-6g) are mostly associated with clay minerals. cao and mgo have a strong positive correlation (fig. 6h), which probably stems from their interrelationship in dolomite and in clay minerals as cations. the content of na2o and cao in silicate minerals is usu­ ally associated with plagioclase. consequently, the negative cor­ relation of na2o with al2o3 and the weak correlation with sio2 (fig. 6i) probably reflects the depletion of na2o suggesting chemi­ cal weathering or recycling of plagioclase. the discriminant functions defined by roser & korsch (1988) for distinguishing source rocks of clastic sediments on the basis of the content of certain macroelements confirmed the results of analyses of the modal composition of the detritus, according to which the latter originated predominantly from older siliciclastic sedimentary rocks and acidic and neutral magmatic rocks (fig. 7). geochemical analyses also showed that pelitic sediments have a more homogeneous chemical composition than the sandy sedi­ ments. they are usually grouped around the boundary of felsite igneous and quartz sedimentary rocks. sandy material is distributed in the fields of neutral and felsitic igneous rocks and quartz sediments (fig. 7). the highest concentration of quartz in the sands is the probable reason for the movement of this group of samples towards the field of felsitic igneous and quartz sedimentary rocks. the sio2 / al2o3 ratio is a measure of the maturity of clastic sediments, and a measure of the presence of quartz and chert ver­ sus clay minerals and feldspars (potter, 1978; cullers, 2000). in the analysed samples, this ratio ranged from 2.59 to 23.87. high values of this ratio, as in the analysed sands and pelitic sediments (tab. 4), indicate the chemical maturity of the vb from vukomeričke gorice which as expected, is higher for the sandy samples. this is consistent with the results of the analy­ sis of the modal composition of the same sediments. the k2o/ al2o3 ratio is used as an indicator of the source composition of pelitic sediments. this ratio ranges from 0 to 0.3 and is charac­ teristic for clay minerals, while for feldspars it ranges from 0.3 to 0.9 (cox et al., 1995). analysed pelitic samples have a k2o / al2o3 ratio which averages 0.18 in the analysed pelitic sediments (tab. 4), indicating older pelitic sediments as source rocks or pelitic detritus. the cia index, as defined by nesbit & young (1982), indicates medium to high intensity of chemical weathering in the source area (tab. 4), and the same is indicated in a ternary diagram based on the ratios of al2o3­(cao + na2o)­ k2o (fig. 8). the samples from the area of vukomeričke gorice are grouped near the al2o3­k2o line and follow the trend of granodiorite weathering. the icv index defined by cox et al. (1995), measures the abundance of alumina in relation to the other cations in a rock or minerals with the elimination of quartz dilu­ tion. this index varies for the analysed pelitic sediments from 0.68–1.16 indicating that most of the sediments are composition­ ally mature and were likely dominated by recycling processes. however, several samples have an icv> 1 (tab. 4), suggesting the input of material only from rocks of the first sedimentary cy­ cle. namely, according to cox et al. (1995), compositionally ma­ ture mudrocks have low values of icv (<1) and are poor with nonclay silicates or rich in the kaolinite group of minerals. such sediments are associated with tectonic quiescent areas or cratons (weaver, 1989) with multiple recycled sediments, but can also figure 7. provenance discriminant function diagram according to roser and korsch (1988) for differentiating the types of source rock showing that most of the sediments from the viviparus beds of the vukomeričke gorice area originate primarily from quartzose sedimentary rock, then from felsic igneous rock and to a lesser extent from intermediate igneous source rock. data from table 4. legend: df1 = 30,638tio2/al2o3 12,541fe2o3/al2o3 + 7,329mgo/al2o3 + 12,031na2o/al2o3 + 35,402k2o/al2o3 6,382; df2 = 56,500tio2/al2o3 10,879fe2o3/al2o3 + 30,875mgo/al2o3 5,404na2o/al2o3 + 11,112k2o/al2o3 3,89. figure 8. al2o3-(cao+na2o)-k2o ternary plot with samples of the viviparus beds from the area of vukomeričke gorice (according to nesbitt & young 1982; 1984). our data are compared with the data for post-archaic australian shale (paas) and with the composition of the upper crust (uc) (taylor & mclennan, 1985), with a composition of north american shale (nasc) (gromet et al., 1984) and with idealized mineral compositions of plagioclase, k-feldspar, kaolinite, muscovite, illite and smectite. numbers 1 & 2 mark trends of changes in the composition of granodiorite (1) & granite (2) as a result of weathering (nesbitt & young 1984). data from table 4. g eologia c roatica 267kurečić et al.: mineral assemblage and provenance of the pliocene viviparus beds from the area of vukomeričke gorice, central croatia be formed as a product of the intensive chemical weathering of materials within the first sedimentary cycle (barshad, 1966). compositionally immature mudrocks have high values of the icv index (>1) and a high proportion of nonclay minerals or, are rich with smectites and illitic material. they are characteristic for the first sedimentary cycle deposits and tectonically active settings (cox et al., 1995 and references therein). results of the trace element analysis (tab. 5) show strong correlation with the mineral and petrographic composition of the sediment. figure 9. shows that the major part of the analysed samples is from the rhyodacite dacite field and a smaller part from the trachyandesite field. only a few samples are distributed over the andesite field. these results of the provenance analyses cor­ respond to the results of the discriminant diagram according to roser & korsch (1988) (fig. 7). 5.2. geotectonic setting of the source area diagrams for determining the geotectonic position of the source areas based on the composition of the main detrital modes (fig. 10) show that most of the sand detritus from the vb is of orogenic origin, i.e., it comes from a recycled orogen. the very high con­ tent of monocrystalline quartz and polycrystalline quartz parti­ cles together with fragments of older sedimentary rocks and low­ grade metamorphic rocks (metapsamites), suggests the origin of the sand detritus from the collision orogen (according to dick­ inson & suczek, 1979). this interpretation is supported by the low concentration of feldspar and particles of volcanic origin. a much smaller number of samples indicates the origin of mate­ rial from the inner craton (fig. 10). however, as the investigated area of vukomeričke gorice is located in the wider area sur­ rounded by high orogens such as the dinarides and the alps, it can be assumed that this material is also of orogenic origin, only it has been modified more. in addition, the chemical composition of the sandy and pelitic sediments from the vb indicates the oro­ genic origin of the material. ternary diagrams based on the ratio of trace elements (fig. 11) showed that the analysed sediments originated from the area of continental island arcs, to which mag­ matic arcs and recycled orogens are assigned as provenance types according to bhatia & crook (1986). these results are con­ sistent with the results of kovačić (2004) and grizelj et al. (2017), who investigated upper miocene sands and pelitic sedi­ ments in the southwestern part of the pannonian basin system, according to which most of this detritus originates from the re­ cycled orogen. summarizing all data concerning the provenance, leads to the conclusion that the clastic debris of the vb originated in a tectonically complex and lithologically heterogeneous source area. the rocks, which were originally located at different geo­ tectonic positions, were weathered with moderate or high chemi­ cal and mechanical intensity. however, due to cretaceous-mio­ cene subduction and the continental collision of the european plate and several smaller continental fragments from the south, the rocks formed at different geotectonic positions were brought into contact with each other and lifted to the surface, creating large mountain ranges around the pbs (royden, 1988; schmit 2008). during the late miocene, weathering of newly uplifted orogens (mainly the alps and western carpathians) led to the production of huge amounts of clastic detritus that infilled the southwestern part of the pbs (kovačić & grizelj, 2006). figure 9. nb/y vs. zr/tio2 discrimination diagram according to winchester & floyd (1977) for sandy and pelitic viviparus beds samples from the area of vukomeričke gorice compared to the plots of upper miocene (bbr-1) and quaternary (orl-1) samples. data from table 5. figure 10. tectonic discrimination diagrams (dickinson et al., 1983) for sandy viviparus beds samples from vukomeričke gorice and slavonia. data from table 1. legend: qzm=monocrystalline quartz; qzt=monocrystalline+polycrystalline quartz; f=potassium feldspar+plagioclase; l=lithic particles; lt=polycristalline quartz+other lithic particles. g eo lo gi a c ro at ic a 268 geologia croatica 74/3 later, at the end of the miocene and during the pliocene, some blocks within the pbs itself were uplifted due to compression (tomljenović & csontos, 2001). this led to the erosion and redeposition of the upper miocene detritus of the alpine­ carpathian provenance, and also to the weathering of newly up­ lifted older rocks within the southwestern part of the pbs and to a lesser extent to the transport of material from the inner dinari­ des. all this material together forms the present detritus of the investigated vb deposits. 6. conclusions the results of analyses of the chemical, mineralogical and petro­ graphic composition of the pliocene viviparus beds from vukomeričke gorice showed that: 1) the viviparus beds are characterized by vertical and lateral interweaving of relatively compositionally mature and texturally immature pelitic and sandy sediments. 2) pelitic sediments consist mainly of quartz and smectite, and to a lesser extent of calcite, dolomite, feldspar, illite/musco­ vite and kaolinite, while chlorite is present in only a few samples. this composition of pelitic sediments is mainly of detrital origin, but is also partly the product of chemical weathering in relatively warm and humid climates. 3) the composition of the sand detritus is dominated by quartz and particles of highly resistant rock, which are formed by weathering of rock from a recycled orogen. 4) the majority of the sand detritus from the viviparus beds is of orogenic origin, i.e., bulk of the detritus was derived from recycled orogen. 5) the source rocks of the detritus of the viviparus beds were moderately to intensively chemically weathered, mostly upper miocene sediments of alpine origin. to a lesser extent palaeogene clastics, triassic limestones and dolomites were the source of de­ tritus, and some of the material also originated from older volca­ nic and low­grade metamorphic rocks. 6) clastic detritus can also be of local origin. the most im­ portant sources were located in the area of the medvednica and žumberak mts. a smaller amount of detritus was derived from the area of moslavačka gora mt. and banovina. 7) a small amount of the detritus of the viviparus beds from slavonia and banovina was brought from the south and origi­ nated in the inner dinarides. 8) differences in the composition of the clastic detritus of the underlying upper miocene sediments deposited in lake pannon and of the detritus of the viviparus beds deposited in lake sla­ vonia are a consequence of the pbs inversion, which during the pliocene led to uplift and erosion of the mountains in the sw part of the pbs. acknowledgement this paper represents a part of the doctoral thesis of tomislav kurečić. the research was funded within the project of the ministry of science, education and sport of the republic of croatia: basic geological map of the republic of croatia, 1:50.000 (pro­ ject no.: 181-1811096-1093). this work has been also supported in part by croatian science foundation under the project ip­2019­ 04-7042. the authors are thankful to all persons involved in the field research and all laboratory technicians involved in the sample preparation. the authors would like to thank the associate editor dr. dunja aljinović and the reviewers (dr. davor pavelić and an anonymous reviewer) for their thorough reviews which have significantly improved the manuscript. we would also thank to dr. lara wacha for the linguistic revision. references andò, s., garzanti, e., padoan, m. & limonta, m. (2012): corrosion of heavy minerals during weathering and diagenesis: a catalog for optical analysis.– sedimentary geology, 280, 165–178. doi: 10.1016/j.sedgeo.2012.03.023 basu, a. (1985): influence of climate and relief on compositions of sands released at source areas.– in: zuffa g.g. (ed.): provenance of arenites. reidel publ. comp., boston, 1–18. doi: 10.1007/978-94-017-2809-6_1 barshad, i. (1966): the effect of a variation in precipitation on the nature of clay mineral formation in soils from acid and basic igneous rocks.– proc. intl. clay conf., 167–173. belak, m., pamić, j., kolar-jurkovšek, t., peckay, z. & karan, d. (1995): alpinski regionalmetamorfni kompleks medvednice (sjeverozapadna hrvatska).– in: vlahović, i., velić, i. & šparica, m. (eds.): 1st croatian geologic congress, opatija, proceedings, 1, 67–70. figure 11. ternary, tectonic discrimination diagrams (after bhatia and crook, 1986) for sandy and pelitic viviparus bed samples from vukomeričke gorice. the values from the upper continental crust (ucc), total continental crust (tc) and ocean crust (oc) were plotted after taylor & mclennan (1985). data from table 5. g eologia c roatica 269kurečić et al.: mineral assemblage and provenance of the pliocene viviparus beds from the area of vukomeričke gorice, central croatia bhatia, m.r., crook, k.a.w. (1986): trace element characteristics of graywackes and tectonic setting discrimination of sedimentary basins.– contributions to mineralogy and petrology, 92, 181–193. doi: 10.1007/bf00375292 brlek, m., kutterolf, s., gaynor, s., kuiper, k., belak, m., brčić, v., holcova, k., wang, k., bakrač, k., hajek-tadesse, v., mišur, i., horvat, m., šuica, s. & schaltegger, u. (2020): miocene syn-rift evo­ lution of the north croatian basin (carpathian–pannonian region): new con­ straints from mts. kalnik and požeška gora volcaniclastic record with regional implications.– int. j. earth sci., 109, 2775–2800. doi: 10.1007/s00531-02001927­4 chamley, h. (1989): clay sedimentology.– springer-verlag, berlin, 623 p. doi: 10.1007/978-3-642-85916-8 cox, r., dengate, j. & cullers, r.l. (1995): the influence of sediment recycling and basement composition on evolution of mudrock chemistry in the southwestern united states.– geochim. et cosmochim. acta, 59, 2919–2940. doi: 10.1016/00167037(95)00185­9 crnko, j. (1990): osnovna geološka karta republike hrvatske 1:100.000, list kutina l 33­90 [basic geological map of the republic of croatia 1:100000, kutina sheet – in croatian].– hrvatski geološki institut zagreb, 2014. crnko, j. & vragović, m. (1990): osnovna geološka karta republike hrvatske 1:100.000.– tumač za list kutina l 33-94 [basic geological map of the republic of croatia 1:100000, geology of the kutina sheet – in croatian].– hrvatski geološki institut zagreb, 2014. cullers, r.l. (2000): the geochemistry of shales, siltstones and sandstones of penn­ sylvanian-permian age, colorado, usa: implications for provenance and meta­ morphic studies.– lithos, 51, 181–203. doi: 10.1016/s0024-4937(99)00063-8 cvetković, m. (2013): naftnogeološki potencijal i litostratigrafska raščlamba trećega neogensko-kvartarnoga megaciklusa savske depresije [lithostratigraphic units of the third neogene-quarternary megacycle in the sava depression and their petroleum potential – in croatian, with an english abstract].– unpubl. phd thesis, faculty of mining, geology and petroleum engineering, university of zagreb, 175 p. ćorić, s., pavelić, d., rögl, o., vrabac, s., avanić, r. & vranjković, a. (2009): revised middle miocene datum for initial marine flooding of north croatian basins (pannonian basin system, central paratethys).– geol. croat., 62, 31–43. doi: 10.4154/gc.2009.03 dickinson, w.r. (1985): interpreting provenance relations from detrital modes of sandstones.– in: provenance of arenites (ed. g.g. zuffa), reidel publ. comp., 333–361, boston. doi: 10.1007/978-94-017-2809-6_15 dickinson, w.r. & suczek, c.a. (1979): plate tectonics and sandstone composi­ tions.– american association of petroleum geology bulletin, 63, 2164–2182. eberl, d.d. (2003): user’s guide to rockjock a program for determining quantita­ tive mineralogy from powder x-ray diffraction data.– u.s. geological survey open­file report 2003­78, 47 p. fedorov, a.v., brierley, c.m., lawrence, k.t., liu, z., dekans, p.s. & ravelo, a.c. (2013): patterns and mechanisms of early pliocene warmth.– na­ ture, 496, 44–49. doi: 10.1038/nature12003 filjak, r. (1951): izvještaj o geološkom kartiranju strukture „kravarsko“ [report on geological mapping of the “kravarsko” structure – in croatian].– institut za geološka istraživanja, fond struč. dok. geol. zavoda, 1927, zagreb. goričan, š., halamić, j., grgasović, t. & kolar-jurkovšek, t. (2005): stratigraphic evolution of triassic arc-backarc system in northwestern croatia.– bulletin de la societe geologique de france, 176, 3–22. doi: 10.2113/176.1.3 grizelj. a., tibljaš, d. & kovačić, m. (2007): mineralogy and geochemistry of upper miocene pelitic sediments of zagorje basin (croatia): implication for evo­ lution of pannonian basin.– geol. carpath., 58/3, 263–276. grizelj, a., peh, z., tibljaš, d., kovačić, m. & kurečić, t. (2017): mineralogical and geochemical characteristics of miocene pelitic sedimentary rocks from the south­western part of the pannonian basin system (croatia): implications for provenance studies.– geosci. front., 8, 65–80. doi: 10.1016/j.gsf.2015.11.009 grizelj, a., milošević, m., bakrač, k., galović, i., kurečić, t., hajektadesse, v., avanić, r., miknić, m., horvat, m., čaić janković, a. & matošević, m. (2020): palaeoecological and sedimentological characterisa­ tion of middle miocene sediments from the hrvatska kostajnica area (croatia).– geol. croat., 73/3, 153–175. doi: 10.4154/gc.2020.15 halamić, j., goričan, š., slovenec, d. & kolar-jurkovšek, t. (1999): middle jurassic radiolarite-clastic succession from the medvednica mt. (nw cro­ atia).– geol. croat., 52/1, 29–57. doi: 10.4154/gc.1999.03 halamić, j., belak, m., pavelić, d., avanić, r., filjak, r., šparica, m., brkić, m., kovačić, m., vrsaljko, d., banak, a. & crnko,j. (2019): osnovna geološka karta republike hrvatske mjerila 1 : 50 000 – požeška gora [basic geological map of the republic of croatia 1:50000 – požeška gora – in croatian].– croatian geological survey, department of geology, zagreb. harzhauser, m. & mandic, o. (2008): neogene lake systems of central and south-eastern europe: faunal diversity, gradients and interrelations.– palaeogeogr. palaeoclimatol. palaeoecol., 260, 417–434. doi: 10.1016/j.palaeo.2007.12.013 horváth, f. (1993): towards a mechanical model for the formation of the pannonian basin.– tectonophysics, 226, 333–357. doi: 10.1016/0040-1951(93)90126-5 horváth, f. (1995): phases of compression during the evolution of the pannonian basin and its bearing on hydrocarbon exploration.– march. petrol. geol., 12, 147–154. doi: 10.1016/0264-8172(95)98851-u hrvatski geološki institut (2009): geološka karta republike hrvatske, m 1:300.000 [geological map of the republic of croatia, m 1: 300.000 – in croatian].– hrvatski geološki institut, zavod za geologiju, zagreb. jackson, m. l. (1956): soil chemical analysis – advanced course.– medison. wisconsin, published by the author, 984 p. doi: 10.1002/jpln.19590850311 jenko, k. (1944): stratigrafski i tektonski snošaj pliocena južnog pobočja požeške gore i kasonje brda.– vjestnik hrvatskog državnog geoložkog zavoda i hrvatskog državnog geoložkog muzeja, 2/3, 89–159. juhász, g. (1991): lithostratigraphical and sedimentological framework of the pan­ nonian (s.l.) sedimentary sequence in the hungarian plain (alföld), eastern hun­ gary.– acta geol. hung., 34/1–2, 53–72. juhász, g. & magyar, i. (1992): review and correlation of the late neogene (pan­ nonian s.l.) lithofacies and mollusc biofacies in the great plain, eastern hungary.– földtani közlöny, 122/2–4, 167–194. kastmüller, ž., kruk, b. & kovačić, m. (2005): mineralne sirovine za ciglar­ sku industriju – ležišta ciglarske gline „rečica“ i kremenog pijeska „brezovi re­ bar“.– in: 3. hrvatski geološki kongres – opatija 2005, 20–21, hrvatski geološki institut, zagreb. kováč, m., nagymarosy, a., oszczypko, n., csontos, l., slaczka, a., marunteanu, m., matenco, l. & márton, e. (1998): palinspatic re­ construcion of the carpathian-pannonian region during the miocene.– in: rakús, m. (ed.): geodynamic development of the western carpathians.− mineralia slo­ vaca-monograph, bratislava, 189–217. kovačić, m. (2004): sedimentologija gornjomiocenskih naslaga jugozapadnog dijela panonskog bazena [sedimentology of the upper miocene deposits from the southwest part of the pannonian basin – in croatian, with an english abstract].– un­ publ. phd thesis, faculty of science, university of zagreb, 203 p. kovačić, m., zupanič, j., babić, lj., vrsaljko, d., miknić, m., bakrač, k. hećimović, i., avanić, r. & brkić, m. (2004): lacustrine basin to delta evolution in the zagorje basin, a pannonian sub-basin (late miocene: pontian, nw croatia).– facies, 50, 19−33. kovačić, m. & grizelj, a. (2006): provenance of the upper miocene clastic mate­ rial in the southwestern part of the pannonian basin.– geol. carpath., 57, 495–510. kovačić, m., horvat, m., pikija, m. & slovenec, d. (2011): composition and provenance of neogene sedimentary rocks of dilj gora mt. (south pannonian ba­ sin, croatia).– geol. croat., 64, 121–132. doi: 10.4154/gc.2011.10 kurečić, t. (2017): sedimentologija i paleoekologija pliocenskih viviparus slojeva vukomeričkih gorica [sedimentology and paleoecology of pliocene viviparus beds from the area of vukomeričke gorice – in croatian, with an english ab­ stract].– unpubl. phd thesis, faculty of science, university of zagreb, 168 p. lubenescu, v. & lubenescu, d. (2008): neogenul superior – strate cu paludine din romania.– studii si cercetari de geologie, 51–53, 77–88. lugović, b., slovenec, d., halamić, j. & altherr, r. (2007): petrology, geochemistry and tectonic significance of mesozoic ultramafic rocks from the zagorje-mid-transdanubian zone in croatia.– geol. carpath., 58/6, 511–530. lužar-oberitter, b., mikes, t., von eynatten, h. & babić, lj. (2009): ophiolitic detritus in cretaceous clastic formations of the dinarides (nw croatia): evidence from cr-spinel chemistry.– int. j. earth sci., 98/5, 1097–1108. doi: 10.1007/s00531-008-0306-3 lužar-oberitter, b., cvetko-tešović, b., moro, a., martinuš, m., aščić, š., marković, f. & balen, d. (2019): traces of the late cretaceous to paleogene collision in the dinarides: evidence from sandstone petrography and geochemistry.– in: horvat, m., matoš, b. & wacha, l. (ur.) 6. hrvatski geološki kongres s međunarodnim sudjelovanjem: knjiga sažetaka – 6th croatian geological congress with international participation: abstracts book. magyar, i., geary, d.h. & müller, p. (1999): palaeogeographic evolution of the late miocene lake pannon in central europe.– palaeogeogr., palaeoclimatol., palaeoecol., 147, 151–167. doi: 10.1016/s0031-0182(98)00155-2 magyar, i. & geary, d.h. (2012): biostratigraphy in a late neogene caspian­type lacustrine basin: lake pannon, hungary.– in baganz, o. w., bartov, y., bohacs, k. and nummedal d. (eds.): lacustrine sandstone reservoirs and hydrocarbon systems: aapg memoir 95, p. 255–264. doi: 10.1306/ 13291392m953142 magyar, i., radivojevic, d., sztanó, o., synak, r., ujszászi, k. & póc­ sik, m. (2013): progradation of the paleo­danube shelf margin across the pan­ nonian basin during the late miocene and early pliocene.– global planet. change, 103, 168–173. doi: 10.1016/j.gloplacha.2012.06.007 majer, v. (1983): magmatske stijene „spilit – keratofirske asocijacije“ iz tercijarnih konglomerata s oboda zrinske gore u baniji (hrvatska, jugoslavija) [magmatic rocks of spilit – keratophyre association from tertiary conglomerates from the edge of zrinska gora in banija (croatia, yugoslavia) – in croatian].– rad jazu, 404, 33, 27–52. g eo lo gi a c ro at ic a 270 geologia croatica 74/3 mange, m.a. & maurer, h.f.w. (1992): heavy minerals in colour.– chapman & hall, london, 151 p. doi: 10.1007/978­94­011­2308­2 matenco, l. & radivojević, d. (2013): on the formation and evolution of the pannonian basin: constraints derived from the structure of the junction area be­ tween the carpathians and dinarides.– tectonics, 31, 1944–9194. doi: 10.1029/ 2012tc003206 mandic, o., de leeuw, a., bulić, j., kuiper, k.f., krijgsman, w. & jurišić-polšak, z. (2012): paleogeographic evolution of the southern panno­ nian basin: 40ar/39ar age constraints on the miocene continental series of north­ ern croatia.– int. j. earth sci., 101, 1033–1046. doi: 10.1007/s00531-011-0695-6 mandic, o., de leeuw, a., bulić, j., kuiper, k., krijgsman, w. & jurišićpolšak, z. (2012): paleogeographic evolution of the southern pannonian basin: 40ar/ 39ar age constraints on the miocene continental series of northern croa­ tia.– int. j. earth sci., 101, 1033–1046. doi: 10.1007/s00531-011-0695-6 mandic, o., kurečić, t., neubauer, t.a. & harzhauser, m. (2015): strati­ graphic and paleogeographic significance of lacustrine mollusks from the pliocene viviparus beds in central croatia.– geol. croat., 68, 179–207. doi: 10.4154/ gc.2015.15 mandic, o., hajek-tadesse, v., bakrač, k., reichenbacher, b., gri­ zelj, a. & miknić, m. (2019): multiproxy reconstruction of the middle mio­ cene požega palaeolake in the southern pannonian 2 basin (ne croatia) prior to the badenian transgression of the central paratethys sea.– palaeogeogr., palaeo­ climatol., palaeoecol., 516, 203–219. doi: 10.1016/j.palaeo.2018.12.003 marinescu, f., papaianopol, i. (eds) (1995): chronostratigraphie und neostra­ totypen, bd. ix, pl1. dacien. editura academiei române, bucuresti. mattick, r.e., phillips, r.l. & rumpler, j. (1988): seismic stratigraphy and depositional framework of sedimentary rocks in the pannonian basin in the south­ eastern hungary.– in: vakarcs, g., vail, p.r., tari, g., pogácsás, gy., mattick, e.r. & szabó, a. (1994): third­order middle miocene­early plio­ cene depositional sequences in the prograding delta complex of the pannonian basin.– tectonophysics, 240, 81–106. doi: 10.1016/0040-1951(94)90265-8 marković, f., kuiper, k., ćorić, s., hajek-tadesse, v., hernitzkučenjak, m., bakrač, k., pezelj, đ., kovačić, m. (2021): middle miocene marine flooding: new 40ar/39ar age constraints with integrated bi­ ostratigraphy on tuffs from the north croatian basin.– geologia croatica, (this issue). mišur, i. (2017): geodinamska evolucija metasedimentnih stijena niskog stupnja metamorfizma na medvednici [geodynamic evolution of low grade metasedimentary rocks on the mt. medvednica – in croatian, with an english abstract].– unpubl. phd thesis, faculty of science, university of zagreb, 215 p. mitchell, j. k. & soga, k. (2005): fundamentals of soil behavior (3rd edition), john wiley & sons, new jersey. 558 p. morton, a.c. & hallsworth, c.r. (1994): identifying provenance-specific fea­ tures of detrital heavy mineral assemblages in sandstones.– sed. geol., 90, 241–256. doi: 10.1016/0037-0738(94)90041-8 morton, a.c. & hallsworth, c.r. (1999): processes controlling the composi­ tion of heavy mineral assemblages in sandstones.– sed. geol., 124, 3–29. doi: 10.1016/s0037-0738(98)00118-3 müller, p., geary, d.h. & magyar, i. (1999): the endemic molluscs of the late miocene lake pannon: their origin, evolution, and familylevel taxonomy.– le­ thaia, 32, 47–60. doi: 10.1111/j.1502-3931.1999.tb00580.x nesbitt, h.w. & young, g.m. (1982): early proterozoic climates and plate motions inferred from major element chemistry of lutites.– nature, 299, 715–717. doi: 10.1038/299715a0 nesbitt, h.w. & young, g.m. (1984): prediction of some weathering trends of plutonic and volcanic rocks based on thermodynamic and kinetic considerations.– geochim. cosmochim. acta, 48, 1523–1534. doi: 10.1016/0016-7037 (84)90408­3 neubauer, t.a., harzhauser, m., kroh, a., georgopoulou, e. & man­ dic, o. (2015): a gastropod­based biogeographic scheme for the european neo­ gene freshwater systems.– int. j. earth sci., 143, 98–116. doi: 10.1016/j.earsci­ rev.2015.01.010 neumayr, m. & paul, c.m. (1875): congerienund paludienschichten slavoniens und deren faunen. ein beitrag zur descendenz-theorie.– abh. k. k. geol. r.-a., 7, 1–106. ožegović, f. (1944): prilog geologiji mladeg terciara na temelju podataka iz novijih dubokih bušotina u hrvatskoj [a contribution to the geology of the tertiary based on data from deep wells in croatia – in croatian].– vjestnik hrvatskog državnog geoložkog zavoda i hrvatskog državnog geoložkog muzeja, 2/3, 391–491. panalytical (2008): x’pert highscoreplus, version 2.2d (2.2.4).– almelo, nizozemska pavelić, d. & kovačić, m. (1999): lower miocene alluvial deposits of the požeška mt. (pannonian basin, northern croatia): cycles, megacycles and tectonic impli­ cations.– geologia croatica, 52/1, 67–76. doi: 10.4154/gc.1999.05 pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bos­ nian sector of the miocene pannonian basin system.– basin res., 13, 359–376. doi: 10.1046/j.0950-091x.2001.00155.x pavelić, d., avanić, r., kovačić, m., vrsaljko, d. & miknić, m. (2003): an outline of the evolution of the croatian part of the pannonian basin system.– in: vlahović, i., tišljar, j. (eds.), evolution of depositional environments from the palaeozoic to the quaternary in the karst dinarides and the pannonian basin. 22nd ias meeting of sedimentology, opatija – sept. 17–19, 2003. field trip guidebook, zagreb, 155–161. pavelić, d., kovačić, m., banak, a., jiménez-moreno, g., marković, f., pikelj, k., vranjković, a., premužak, l., tibljaš, d. & belak, m. (2016): early miocene european loess: a new record of aridity in southern eu­ rope.– geol. soc. am. bull., 128, 110–121. doi: 10.1130/b31280.1. pavelić, d. & kovačić, m. (2018): sedimentology and stratigraphy of the neogene rift-type north croatian basin (pannonian basin system, croatia): a review.– ma­ rine and petroleum geology, 91, 455–469. doi: 10.1016/j.marpetgeo.2018.01.026 pdf-4/minerals (2016): international centre for diffraction data. sn: minc160138-9766. pikija, m. (1987a): osnovna geološka karta sfrj 1:100.000, tumač za list sisak l33– 93 [basic geological map of sfry 1:100000, geology of the sisak sheet – in croatian].– geološki zavod, zagreb (1975–1986), savezni geološki institut, beo­ grad, 56 p. pikija, m. (1987b): osnovna geološka karta sfrj 1:100 000, list sisak [basic geological map of sfry 1:100000, sisak sheet – in croatian].– inst. za geol. istraž., zagreb, inst. za geol., sarajevo, sav. geol. zavod, beograd. piller, w.e. & harzhauser, m. (2005): the myth of the brackish sarmatian sea.– terra nova, 17, 450–455. doi: 10.1111/j.1365-3121.2005.00632.x potter, p. (1978): petrology and chemistry of modern big river sands.– the journal of geology, 86/4, 423–449. doi: 10.1086/649711 rögl, f. (1999): mediterranean and paratethys. facts and hypotheses of an oligocene to miocene paleogeography (short overview).− geol. carpath., 50/4, 339−349. roser, b.p. & korsch, r.j. (1988): provenance signatures of sandstone-mudstone suites using discriminant function analysis of major-element data.– chemical ge­ ology, 67, 119–139. doi: 10.1016/0009-2541(88)90010-1 royden, l.h. (1988): late cenozoic tectonics of the pannonian basin system.– in: royden l.h. & horvath, i.f. (eds): the pannonian basin. a study in basin evolution, aapg memoir, tulsa, 45, 27–48. royden, l.h. & horvath, f. (1988): the pannonian basin. a study in basin evolu­ tion. the american association of petroleum geologists and the hungarian geo­ logical society.– aapg memoir, 45, map 8. doi: 10.1306/m45474 rundić, lj., vasić, n., životić, d., bechtel, a., knežević, s. & cvetkov, v. (2016): the pliocene paludina lake of pannonian basin: new evidence from northern serbia.– annales societatis geologorum poloniae, 86, 185–209. doi: 10.14241/asgp.2016.003 saftić, b., velić, j., sztano, o., juhasz, g. & ivković, ž. (2003): tertiary subsurface facies, source rocks and hydrocarbon reservoirs in the sw part of the pannonian basin (northern croatia and south-western hungary).– geol. cro­ at., 56/1, 101–122. schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine– carpathian–dinaridic orogenic system: correlation and volution of tectonic units.– swiss j. geosci., 101, 139–183. doi: 10.1007/s00015-008-1247-3 slovenec, d. & šegvić, b. (2019): boninite volcanic rocks from the mélange of nw dinaric-vardar ophiolite zone (mt. medvednica, croatia) – record of middle to late jurassic arc-forearc system in the tethyan subduction factory.– mineralogy and petrology, 113/1, 17–37. doi: 10.1007/s00710-018-0637-0 starijaš, b., gerdes, a., balen, d., tibljaš, d. & finger, f. (2010): the moslavačka gora crystalline massif in croatia: a cretaceous heat dome within remnant ordovician granitoid crust.– swiss j. geosci., 103/1, 61–82 doi: 10.1007/ s00015­010­0007­3 starkey, h.c., blackmon p.d. & hauff p.l., (1984): the routine mineralogi­ cal analysis of clay-bearing samples.– u.s. geological survey bulletin 1563, washington, 31 p. doi: 10.3133/b1563 šćavnićar, b. (1979): pješčenjaci pliocena i miocena savske potoline [sandstones of the miocene and pliocene age in the sava depression − in croatian, with an english abstract].− scientific commitee for petroleum of the yugoslavian acad­ emy of science and art (jazu), 3rd scientific congress of section for applied ge­ ology, geophysics and geochemistry, novi sad (1977), zagreb, 2, 351–383. šebečić, b. (1971): the granulometric and petrographic composition od the eocene deposits of zrinska gora and kozara mountains.– bulletin scientifique, section a –16, 3–4, 1971. šebečić, b. (2010): o povijesti istraživanja i eksploatacije vukomeričkih lignita [abouth research and exploitation history of vukomerička lignite – in croatian].– rudarsko-geološko-naftni zbornik, 22, 81–90. šikić, k., basch, o. & šimunić, a. (1978): osnovna geološka karta sfrj 1:100.000, list zagreb l33­80 [basic geological map of sfry, sheet zagreb – in croatian].– institut za geološka istraživanja, zagreb (1972), savezni geološki in­ stitut, beograd. g eologia c roatica 271kurečić et al.: mineral assemblage and provenance of the pliocene viviparus beds from the area of vukomeričke gorice, central croatia šikić, k., basch, o. & šimunić, a. (1979): osnovna geološka karta sfrj 1:100.000 – tumač za list zagreb l33-80 [basic geological map of sfry, sheet zagreb – in croatian].– institut za geološka istraživanja, zagreb (1972), savezni geološki institut, beograd, 81 p. šikić, k. (1990a): osnovna geološka karta republike hrvatske 1:100.000, list bosan­ ski novi l 33-105 [basic geological map of republic of croatia 1:100.000, bosanski novi sheet – in croatian].– hrvatski geološki institut zagreb, 2014. šikić, k. (1990b): osnovna geološka karta republike hrvatske 1:100.000. tumač za list bosanski novi 1:100.000, l 33-70 [basic geological map of republic of croatia 1:100000, geology of the bosanski novi sheet – in croatian].– hrvatski geološki institut zagreb, 2014. šimunić, an. & šimunić, al. (1987): rekonstrukcija neotektonskih zbivanja u sjeverozapadnoj hrvatskoj na temelju analize pontskih sedimenata [reconstruction of neotectonic events in nw croatia based on the analysis of pontian sediments – in croatian].– rad jugosl. akademije znanosti i umjetnosti, 431, 155–177, zagreb. šparica, m., juriša, m., crnko, j., šimunić, an., jovanović, č. & živanović, d. (1980): osnovna geološka karta sfrj 1:100 000. tumač za list nova kapela [basic geological map of sfry 1:100000, geology of the nova kapela sheet – in croatian]. – inst. za geol. istraž., zagreb, inst. za geol., sarajevo, savezni geološki zavod, beograd, 55 p. taylor, s.r., mclennan, s. m. (1985): the continental crust: its composition and evolution.– blackwell, oxford, 312 p. doi: 10.1017/cbo9780511575358.014 thamó­boszó, e. & juhász, g. (2002): mineral composition of upper miocene­ pliocene (pannonian s.l.) sands and sandstones in the different sedimentary sub­ basins in hungary.– geol. carpath., 53, spec. issue, cd with extended abstracts. thamó-bozsó, e., juhasz, gy. & kovacs lajos, ó. (2006): the mineral com­ position of the pannonian s.l. formations in the hungarian plain (i). the charac­ teristics and origins of the pannonian s.l. sands and sandstones.– földtani közlöny, 136/3, 407–429. thamó-bozsó, e. & kovács, ó. (2007): evolution of quaternary to modern flu­ vial network in the mid-hungarian plain, indicated by heavy mineral distributions and statistical analysis of heavy mineral data.– földtani közlöny, 136/3, 491–524. tomljenović, b. & csontos, l. (2001): neogene-quaternary structures in the border zone between alps, dinarides and pannonian basin (hrvatsko zagorje and karlovac basin, croatia).– geol. rundschau, 90, 560–578. doi: 10.1007/ s005310000176 troskot-čorbić, t., velić, j. & malvić, t. (2009): comparison of the middle miocene and the upper miocene source rock formations in the sava depression (pannonian basin, croatia).– geol. croat., 62/2, 123–133. doi: 10.4154/gc. 2009.11 van gelder, i.e., matenco, l., willingshofer, e., tomljenović, b., andriessen, p.a.m., ducea, m.n., beniest, a. & gruić, a. (2015): the tectonic evolution of a critical segment of the dinarides-alps connection: kine­ matic and geochronological inferences from the medvednica mountains, ne cro­ atia.– tectonics, 34, 1952–1978. doi: 10.1002/2015tc003937. velić, j. (1983): neotektonski odnosi i razvitak zapadnog dijela savske potoline [neotectonic relations and development of the western part of sava depression – in croatian].– acta geol. 13/2, 26–65. weaver, c.e. (1989): clays, muds, and shales.– elsevier, amsterdam, 721 p. von eynatten, h. & dunkl, i. (2012): assessing the sediment factory: the role of single grain analysis.– earth-science reviews, 115, 97–120. doi: 10.1016/j.ear­ scirev.2012.08.001 willeit, m., ganopolski, a. & feulner, g. (2013): on the effect of orbital forcing on mid-pliocene climate, vegetation and ice sheets.– clim. past discuss., 9, 1703–1734. doi: 10.5194/cp-9-1749-2013 winchester, j. a., & floyd, p. a. (1977): geochemical discrimination of differ­ ent magma series and their differentiation products using immobile elements.– chemical geology, 20, 325–343. doi: 10.1016/0009-2541(77)90057-2 2019 | 72 / special issue | 81–91 | 4 figs. | 3 tabs. | 2 pls. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society article history: manuscript received april 11, 2019 revised manuscript accepted september 17, 2019 available online december 20, 2019 keywords: xuelongnang, outburst sediment, quartz grains, particle size distribution, gravel fabric 1. introduction scanning electron microscopy (sem) has been widely utilized to collate the observed surface microtextures of quartz grains characterized by grain migration and sedimentary environments. (krinsley & takahashi, 1962; hamilton & krinsley, 1967; whalley & krinsley, 1974; helland & diffendal, 1993; mahaney et al., 2001; krinsley, 2011, immonen, 2013; vos et al., 2014; chen et al., 2019). this method is able to amplify the nanoscale microtexture enough times for examinations to be completed and has been applied in the study of sediment from other sources, such as grains from glacial sediment (mahaney & kalm, 1995); glacial tills (mahaney et al., 1988; mahaney et al., 1996); ice-drift sediment (mahaney & andres, 1991; smalley & glendinning, 1991; mahaney, 1992); loess glaciers (pye, 1983; kenig, 2006); eolian sediment (mahaney & andres, 1996; chakroun et al., 2009); parent rock (molen, 2014) and tsunami deposits (costa et al., 2012). however, it is less common to use sem techniques to study the microtexture of quartz grains in palaeo-landslide outburst sediment. therefore, based on the measurements of the gravel fabric and analysis of the particle size distribution of the sand grains (mahaney & kalm, 1995), and the surface textures of quartz grains, the sedimentary process of the outburst sediment can be better understood. meso/micro-texture analysis of the landslide-dam outburst sediments in the upper jinsha river, se tibetan plateau jian chena*, zhijiu cuib, chao liuc, wendy zhoud and ruichen chena a china university of geosciences beijing, school of engineering and technology, beijing 100083, china; (*corresponding author: tel.: +86 10 82321196; jianchen@cugb.edu.cn) b peking university, college of urban and environmental sciences, beijing 100871, china c university of alberta, department of civil and environmental engineering, edmonton, alberta t6g 2r3, canada d colorado school of mines, department of geology and geological engineering, colorado 80401, usa doi: 10.4154/gc.2019.29 abstract outburst sediments are widely distributed in the upper jinsha river in the southeastern (se) tibetan plateau. in order to understand the sedimentary characteristics of these sediments, gravel fabric, particle size distribution and quartz sand surface textures were used to analyze the mesotextures and microtextures of the xuelongnang outburst sediments. it was determined that these sediments usually have a short transport distance, and are distributed over a distance of approximately 3.5 km. the gravel fabric and particle size distribution analysis represent the different meso-characteristics with different transport distances and suggest gradually changing hydrodynamic conditions. the statistical data of quartz surface textures exhibit the transformation process of quartz sands by outburst flood. the variation from abundant sub-angular shapes (> 75%); to common v-shaped percussion cracks, solution crevasse, medium relief, and chatter marks (50% to 75%); to rare meandering ridge, underwater polished surface, large conchoidal fracture (> 100 μm), directional etch pits, and crystalline overgrowths (< 5%), present the features in different combinations to other sedimentary environments. the microtexture characteristics of landslide-dam outburst deposits are also consistent with those of the mesotextures. as the distance from the residual dam increased, the quartz grain microtextures showed gradual or abrupt changes, such as increased frequencies of v-shaped percussion cracks, decreased frequencies of the adhering particles, and growth of the solution crevasses. these findings could potentially be used as a discriminant mark to distinguish outburst sediment from other types of sediments, e.g., subaqueous, eolian, glacial, etc. although it can be difficult to determine the exact shape of parent-rock quartz grains and their microtexture characteristics, it can be deduced from previous research on mechanically-released quartz in cave walls (mahaney & kalm, 1995), and weathering release processes (molen, 2014). clearly, the transported grains in the outburst deposits were affected by the non-uniform stresses within different parts of a large water mass. it included many variable factors, such as transport distances, velocity and sediment concentration, which resulted in the formation of a variety of different sedimentary characteristics (e.g., gravel fabric; quartz surface textures, and particle size distribution). this study analyzes the sedimentary characteristics of the xuelongnang outburst deposits from multiple aspects. the samples collected were analyzed to become the discriminant criterion of the outburst deposits. it was thought that the sediment was deposited relatively rapidly along the direct contact between the landslide-dam outburst flooding and the underlying river bed, flood plain, and river terraces. the maximum thickness of the sediment was approximately 15 m, and the length was approximately 3.5 km (chen et al., 2013; chen & cui, 2015). during the sedimentary process, the sediments were further transformed by floodwaters and formed specific microtextures. here, the results of the field investigations and sediment sampling were used for laboratory experiments in order to obtain the sedimentary parameters, which included the gravel fabric (orig eo lo gi a c ro at ic a geologia croatica 72 / special issue82 figure 1. location of the study area in the southeastern margin of the tibetan plateau. (a) location map of the study area. (b) geological map of the xuelongnang reach of the upper jinsha river. g eologia c roatica chen et al.: meso/micro-texture analysis of the landslide-dam outburst sediments in the upper jinsha river, se tibetan plateau 83 entation of the axis a and plane ab in gravels and pebbles), and particle size distribution of the sand grains, as well as the surface microtextures of the quartz grains. 2. study area the xuelongnang outburst sediments are located in the upper reaches of the jinsha river, on the southeast margin of the qinghai-tibet plateau, in southwest china, approximately 50 km to the southeast of mangkang (n 29°20’-29°36’, e 98°05’-98°55’), as detailed in figure 1. (chen et al., 2018). the study area has a maximum altitude of 6,000 m, and a minimum altitude of 2,200 m. also, the largest relative relief is 3,800 m, where the river level is approximately 2,300 m. since the late cenozoic, due to uplift of the southeast margin of the qinghai-tibet plateau and strong river cutting action (ma et al., 2018), morphogenesis has produced a gorge in the upstream section of the jinsha river. where the river runs between xuelongnang and wangdalong, its elevation drops to about 2,300 m, with a valley width in xuelongnang of between 100 and 200 m. the slopes of the rock walls on both sides of the gorge are approximately 40 degrees. the valley between xuelongnang and wangdalong has a subtropical arid climate, with an annual precipitation of only 400 mm, with the rainfall concentrated mainly between june and october. in xuelongnang, neotectonic movement is considered to be active. also, the xiongsong-suwalong active fault, which is the major fault of the jinsha river fault zone, crosses eastern xuelongnang (figure 1). in the valley, litho logically the rock outcrops consist mainly of permian schist, igneous rock, and marble. in this region, landslides are fairly common due to the intense development of joints with significant physical weathering and the influence of the active faults in the jinsha river valley. in this study, based on geological and topographic maps and the distance of the sediment from the residual dam, the sediments were divided into three sections: upstream sediment, midstream sediment, and downstream sediment, as shown in figure 2. 3. methodology both field investigation and laboratory examination were undertaken. in order to describe the gravel fabric, gravel samples (> 2 cm) were randomly selected to measure the length and trend of axis a, as well as the orientation of the plane ab. for the purpose of collecting samples for analysis of particle size distribution and quartz grain microtextures, two typical outcrops were selected in each of the three sediment sections (figure 2) for a total of eight sampling areas. in each sampling area, 50 cm × 50 cm squares were drawn on the surface. sediments from the surface to a depth of 30 cm were removed for sampling. we used a chisel and shovel to collect a mixture of coarse gravel and fine sand, and then fine sand was picked from the middle part of the mixture (two samples for each square, and each sample weighed more than 200 g). the particle size distributions of the samples were obtained by following the process described by mahaney (1995), then the sand size particles (0.063 2 mm) were screened out. the fines (< 0.063 mm) were also separated, and a laser diffraction particle size analyzer (mastersizer 3000) was used in order to determine the percentages of silt and clay. the method proposed by vos et al. (2014) was then used to pretreat the sand samples as follows: (1) the sands were dried, and then typically separated (quartered), until about 10 g of sandy grains remained; (2) the sand was placed in a 1 mol/l hcl solution and boiled for 10 minutes to remove carbonates and iron oxide; (3) the sand was washed at least three times using deionized water, until only clean water could be poured out; (4) the sand was placed in a 1 mol/l hydrogen peroxide solution and boiled for 10 minutes to remove the clay and organic matter; (5) the sand was washed at least three times with deionized water until only clean water could be poured out; (6) finally, the sand samples were dried at 60 ℃ for 12 hours. figure 2. distribution of the outburst sediment from the xuelongnang landslide-dammed lake. g eo lo gi a c ro at ic a geologia croatica 72 / special issue84 since it was believed that the formation of microtextures may be associated with grain size (mahaney, 2002), grains of similar size were selected. in this study, quartz grains with sizes ranging between 0.2 and 0.5 mm were selected for microstructural analysis. a zeiss supra tm, from the science institute of the china university of geosciences (beijing), was used for the observations. for each sample, 10 to 20 grains were selected to fix on the double-sided adhesive of the sem samples in particular orientations. the sample was then subject to gold sputtering, as it had been previously determined that gold provides better resolution than other heavy metals or carbon (vos et al., 2014). also, gold coating can reduce beam penetration, which in turn leads to clearer images. however, the most important objective was to minimize the surface charge. in this study, the samples were sputtered and coated, and a 40 ma current was applied for 300 seconds, in order to obtain a gold coating of approximately 250 nm. 4. results and discussions 4.1. sedimentary structure examination of the landslide-dam outburst sediment revealed a fining-downstream pattern within the deposit. the upstream sediment contained many rock blocks, boulders, and erratic blocks, which were either clast-supported or matrix-supported. silty and fine sand formed the matrix, which filled in the inter-grain gaps and pores. in the midstream sediment, large amounts of gravel and pebbles were observed, while boulders or erratic blocks were rarely observed. the downstream sediments were observed to have large amounts of smaller gravel, pebbles, and sand with a crude stratification. also, gravel imbricated structures appeared in some of the coarse layers, which contained significantly more silty and fine sand than the coarse layers observed in the sediments of the other two sections. 4.2. gravel fabric it is known that large sized gravel usually indicates greater hydrodynamic activity. however, when analyzing the hydrodynamic effects of sedimentary processes, the morphology of the gravel is also definitely very important. to a large extent, the gravel fabric of outburst sediment can maintain and reflect both kinematic and dynamic information. therefore, in order to achieve a dynamic equilibrium state, the morphology of highspeed mobile grains must be consistent with the direction and magnitude of the force, so that the dynamic energy of the grains can reach the minimum level (for example, a steady state). in addition, the grains’ position adjustments are also associated with the development of the gravel fabric. under general conditions, the direction of the long axis (axis a) of fluvial sedimentary gravel generally indicates the movement direction of the grain and also shows a large number of the changes related to differential resistance. in an outburst mass with high-speed movement, the tendency of the gravels’ maximum plane (plane ab) usually indicates the maximum stress direction of the grains with a forced movement (pushing movement), and the value of the dip angle could potentially reflect the ratio between the horizontal and vertical stresses. in other words, a larger angle indicates greater horizontal stress, and vice versa. the field investigations revealed the closer the sediment was to the residual dam, the greater the size of the gravel (table 1: 6.3 m, 2.3 m, and 1.7 m). these results were in line with the expectations, since increasing distance from the residual dam leads to decreases in the hydrodynamics, and thereby promotes decreases in the size of the transported particles. similarly, the orientation of plane ab was determined to be strongly influenced by the hydrodynamics (principal horizontal stress), as the orientation of the plane ab for the grains in the study area was found to be close to that of the river’s trend. these findings suggest that the hydrodynamic direction of water flow was the main factor influencing of the grains’ orientation during transportation and deposition. in addition, outburst flooding was characterized by strong explotable 1. axis a data from the xuelongnang outburst sediment. location maximum particle a-axis (average) / m a-orientation (average) / ° upstream 6.3 287.5 midstream 2.3 265.4 downstream 1.7 152.8 figure 3. article size distribution curves for: (a) the upstream sediment, (b) the midstream sediment (c) the downstream sediment. g eologia c roatica chen et al.: meso/micro-texture analysis of the landslide-dam outburst sediments in the upper jinsha river, se tibetan plateau 85 sive mass flow during a short period of time. the dip angle of the outburst sediment was measured to be generally greater than 35°. also, due to the flooding and narrow valleys, the trend of axis a (table 1) displayed no obvious differences, which suggested that the tendency of flooding was inconsistent over a smaller range, and likely affected by the narrow and tortuous channel. 4.3. particle size distribution the particle size distribution of the outburst sediment was analyzed in this study (fig. 3), in an attempt to identify whether the changes in the sand content (especially the medium sand) were related to the differences in the microtexture type and assemblage on the surface of the quartz grains. overall, the sand content of the downstream sediment was found to be the highest (table 2), the sources of which may have been the landslide lake, as well as the residual dam mass. table 2. shows the midstream sediment also contained large amounts of coarse sand (1 to 2 mm grainsize). the upstream sediment curve (figure 3a) was almost a straight-line segment, with the exception of samples sy3-4 and zy2-4. since these samples were collected near the residual dam mass, it may have included finer-grained material from the residual dam or lake sediments upstream. the midstream sediment curve (figure 3b) showed higher contents of fine and silty sand, with poor sorting characteristics. it was determined that as the distance between the sediment and the residual dam increased, the sand content increased, while the silt content decreased. the downstream sediment curves (figure 3c) feature three almost straight-line segments, which indicates that this section of sediment had the poorest sorting. the downstream sediment was determined to have the highest content of fine sand and the lowest content of silty sand. the analyses indicate that among all the samples, the clay content (< 0.002 mm) was minimal (mainly zero, or almost negligible). the minimal clay content may be due to a lack of lacustrine sediment in the provenance area, short sedimentary time, and continuous fluctuations in the water energy, which inhibit development of the required hydrostatic environment for clay sedimentation to occur. these conditions are known to be characteristic of outburst sediments and distinguish them from other sources of sediment (mahaney & kalm, 2000; stuut et al., 2014; luo et al., 2015). it can be seen in table 2. and in fig. 3a, b that the upstream sample sy3-4 and midstream sample zy2-4 show differently shaped grain size distribution curves and average particle size than the other samples within the same group. these anomalies may be due to mixing with material from the residual dam mass and material from the adjacent section of sediment. the features of quartz grain surface textures at different segments were analyzed using a scanning electron microscope (sem). 4.4. surface microtextures of quartz grains in this study, sem was used to observe 172 quartz grains using nearly 1,000 photo images. the quartz surface texture classification proposed by vos et al. (2014) was used in combination with the actual observations. a total of 36 types of possible surface microtextures were divided into three types: mechanical characteristics, chemical characteristics, and mechanical/chemical characteristics. the frequency of occurrence of each microtexture was calculated as a percentage of the samples exhibiting the microtexture. based on the frequency of occurrence, microtextures were classified as abundant (> 75%); common (50% to 75%); sparse (5% to 50%); and rare (< 5%). for the quartz grains among the outburst samples at different locations from the upstream to downstream, it was determined that the most abundant microtexture was a sub-angular shape (plate 1. a, b). common microtextures included v-shaped percussion cracks (plate 1. c, d), medium relief (plate 2. c), solution crevasses (plate 2. a), and chatter marks (plate 2. d). sparse microtextures include low relief, adhering particles (plate 2. e, f), and disc concave pits (plate 1. e, f). rare microtextures included underwater polished surfaces (plate 2. b), large conchoidal fractures (> 100 μm), directional etch pits, crystalline overgrowths, and meandering ridges. imbricate grinding features and scaling were not observed in any of the samples (table 3). in addition, the frequency of occurrence of the microtextures in each sediment section revealed gradual changes within the outburst deposit. the frequency of several microtextures increased with increasing distance from the residual dam. examples include v-shaped percussion cracks, small conchoidal fractures (< 10 μm), graded arcs, parallel striations, and siliceous globules (mainly as mechanical characteristics). it was most interesting to observe that the frequency of adhering particles was gradually reduced, which indicated that the water chemistry was able to remove the particles attached to the grain surfaces. it is also possible that particles close to the residual dam mass collided more frequently and generated more impact debris available for adhering to the grains than particles farther downstream. the collision between the grains of the samples which were closer to the residual dam mass was more frequent, which led to more impact debris adhering to the grains. table 2. grain size component and mean grain size of the xuelongnang outburst sediment. location sample % gravel (2~4 mm) % sand (0.063~2 mm) % silt (0.002~0.063 mm) percentile 25th 50th 75th mean phi upstream sy3-1 0.13 85.05 14.82 0.4 1.2 2.4 1.1 sy3-2 0.23 84.40 15.38 0.0 1.5 2.7 1.4 sy3-3 0.05 79.81 20.13 0.7 1.4 2.5 1.1 sy3-4 0.00 77.77 22.23 2.1 3.2 3.8 2.9 midstream zy2-1 0.17 91.20 8.63 1.7 2.5 3.3 2.5 zy2-2 0.01 85.72 14.27 2.3 3.0 3.7 3.0 zy2-3 0.00 93.61 6.39 1.8 2.4 3.1 2.5 zy2-4 0.74 86.18 13.08 0.2 1.4 2.2 1.1 downstream xy1-1 0.46 91.37 8.17 1.0 1.8 2.7 1.9 xy1-2 0.03 95.86 4.11 1.6 2.3 3.1 2.4 xy1-3 0.05 96.98 2.97 1.6 2.3 2.9 2.4 xy1-4 0.04 93.88 6.08 1.9 2.5 3.2 2.6 g eo lo gi a c ro at ic a geologia croatica 72 / special issue86 ta bl e 3. s ur fa ce m ic ro te xt ur e ca te go rie s o f t he q ua rt z gr ai ns . le ge nd : a b un da nt █ c om m on ● sp ar se ▄ ra re ○ n ot g iv en n ot e: d at a w ith ‘* ’ a re fr om vo s et a l. 20 14 m ec ha ni ca l c he m ic al m ec ha ni ca l a nd c he m ic al 1.angualr contour 2.subangular contour 3.circular contour 4.small conchoidal fracture (<10µm) 5.medium conchoidal fracture (<100µm) 6.large conchoidal fracture (>100µm) 7.arcuate steps 8.straight steps 9.meandering ridges 10.flat cleavage surfaces 11.graded arcs 12.v–shaped percussion cracks 13.straight/curved grooves and scratches 14.upturned plates 15.crescentic percussion marks 16.bulbous edges 17.abrasion fatigue 18.parallel striations 19.imbricate grinding features 20.disc-shaped concave pits 21.directional etch pits 22.solution pits 23.solution crevasses 24.scaling 25.silica globules 26.silica flowers 27.silica pellicle 28.crystalline overgrowths 29.underwater polished surface 30.low relief 31.medium relief 32.high relief 33.elongated depressions 34.chatte rmarks 35.adhering particles 36.arcuate/circular/polygonal cracks subaqueous* fl uv ia l lo w en er gy ● ● ● ○ ○ ○ ○ ○ ○ ○ ○ ▄ ○ ○ ○ ○ ○ ○ ○ ○ ▄ ▄ ○ ● ● ● ▄ ○ █ ○ ○ ○ ○ ○ h ig h en er gy ▄ ● ● █ ● ▄ ● ● ○ ● ▄ █ ● ▄ ▄ ○ ○ ○ ○ ○ ▄ ○ ○ ○ ○ ○ ○ ● █ ● ○ ▄ ○ ○ m ar in e in te rt id al ○ ● █ █ ● ○ ● ● ○ ● ▄ █ █ ▄ ▄ ○ ○ ○ ○ ● ▄ ○ ○ █ █ ○ ○ ○ █ ○ ○ ▄ ○ ○ su b tid al ▄ ● ● ○ ○ ○ ○ ○ ○ ○ ○ ▄ ▄ ○ ○ ○ ○ ○ ○ █ ● ● ○ ○ ○ ○ ○ ○ █ ○ ○ ○ ○ ○ ts un am i ○ ● ● ○ ○ ○ ○ ○ ○ ○ ○ █ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ● ● ○ ○ ○ ○ ○ eolian* li tt or al d un e ○ ● █ ● ▄ ○ ● ▄ ● ▄ ● ▄ ▄ █ ● █ ● ○ ○ ○ ○ ○ ○ ● ● ○ ○ █ ● ○ ● ○ ▄ ○ d es er t d un e ○ ○ █ ● ▄ ○ ▄ ▄ ● ▄ █ ○ ○ █ █ █ █ ○ ○ ▄ ● ● ▄ ○ ○ ● ▄ █ ● ○ ● ○ ▄ ▄ g la ci al * █ ○ ○ █ █ █ █ █ ▄ ● ○ ▄ ● ▄ ○ ○ ● █ ● ○ ○ ○ ○ ○ ○ ○ ○ ○ ● █ ○ ● █ ○ d ia ge ne tic /a lte ra tio n* ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ● ○ ○ ○ ○ ○ ○ ○ ○ ● ● ● ● ● ● ● █ ● ● ○ ○ ○ ● ● ou tb ur st up st re am ▄ █ ○ ▄ ○ ○ ○ ▄ ○ ▄ ▄ ● ○ ▄ ○ ▄ ○ ▄ ○ ▄ ○ ▄ ▄ ○ ▄ ▄ ▄ ○ ○ ▄ ● ○ ▄ ▄ ● ▄ m id st re am ▄ ● ▄ ▄ ▄ ○ ▄ ▄ ○ ▄ ▄ ● ▄ ○ ○ ▄ ○ ▄ ○ ▄ ▄ ○ ● ○ ▄ ○ ▄ ○ ○ ● ▄ ○ ○ ● ● ○ do w ns tr ea m ▄ █ ○ ▄ ▄ ○ ▄ ▄ ○ ▄ ▄ ● ▄ ▄ ▄ ▄ ▄ ▄ ○ ▄ ○ ▄ ● ○ ▄ ▄ ○ ○ ○ ▄ ● ▄ ▄ ● ▄ ▄ to ta l ▄ █ ▄ ▄ ▄ ○ ▄ ▄ ○ ▄ ▄ ● ▄ ▄ ○ ▄ ○ ▄ ○ ▄ ○ ▄ ● ○ ▄ ○ ○ ○ ○ ▄ ● ▄ ▄ ● ▄ ▄ g eologia c roatica chen et al.: meso/micro-texture analysis of the landslide-dam outburst sediments in the upper jinsha river, se tibetan plateau 87 4.4.1. mechanical characteristics the roundness parameter describes the degree of roundness or angularity of grains on the mesoscopic scale. grains are described as angular, sub-angular, or rounded. the grain angularity is not only mainly related to the migration method, migration distance, granularity, and time, but also is correlated to the main shape of the grains in the parent rock (kleesment, 2009; costa et al., 2013). the sub-angular contoured grains are usually associated with an upper flow or intertidal zone, of which the formation requires violent abrasion to make grain edges round (mahanney, 2002; table 3). in addition, chemical effects can also change the grain contour, such as dissolution and precipitation. however, these effects are different from the characteristics of mechanical abrasion. in outburst sediment, abundant sub-angular contours indicate that the sediments are not experiencing long-term water abrasion. however, rapid deposition is known to be consistent with the characteristics of the gravel fabric and granularity distribution. a meandering ridge is a slightly curved intersection line between conchoidal fractures, which can cross the grain’s surface. it features the typical characteristics of grains located in such environments as desert sand transport, coastal dunes, and glaciers (table 3). therefore, it is known to be rare in outburst sediment. similarly, imbricate grinding features exist only in glacial grinding conditions (table 3). therefore, findings of zero percentages of these in outburst sediment are understandable. v-shaped percussion cracks are approximately triangular concave pits with maximum diameters of 5 μm, and average depths of 0.1 μm. usually, v-shaped percussion cracks have random orientations. this is mainly due to the fact that the grains are in high-energy underwater environments (such as coastal areas, braided rivers, and glacial rivers), and the collision between grains is random. in some special conditions, such as a tsunami, the grains will show rapid abrasion in a short period (vos et al., 2014; table 3). it is common that, during the process of a dam burst, the dam-burst flooding is characterized by a very large amount of energy as it flows in narrow valleys, which leads to frequent violent collisions between the suspended grains. however, with increased distances from the residual dams, the larger grains tend to settle, while the collision change between the smaller grains in the water becomes obvious. therefore, their frequency of occurrence downstream will be larger than in the upstream areas. a disc concave pit is similar to a v-shaped percussion crack and is caused by the collision between grains. the formation of these pits requires more energy, as well as more rounded grains. the frequency of occurrence of concave disc pits has increased (figure 4), though they are not always obvious, mainly due to the collision energy not being increased (energy may also have been reduced). the quantity of the rounded grains in the downstream sediment will be greater than the upstream and midstream areas. also, the flow migration and transformation play vital roles on the particle distribution. 4.4.2. chemical characteristics directional etch pits are usually formed in crystal planes with widths of between 1 and 30 μm. they can be distinguished from the v-shaped percussion cracks by their regular and directional appearance. the occurrence of directional etch pits can be attributed to dislocations and defects within the crystal lattice, where the quartz is more likely to dissolve. since dissolution takes a long time, it would be difficult for rapid dam-burst flooding to produce directional etch pits. solution crevasses are dissolved cracks on grain surfaces, which are usually related to dissolved pits with successive formation times. for example, a dissolved pit forms first, and then a solution crevasse is formed on this basis (krinsley & doornkamp, 1973). in this study, it was found that, with the increased distances from the residual dam, the dissolved pits were gradually reduced, while the solution crevasses increased. these findings illustrate the genetic relationship between these features. in flooded environments, the dissolution and diagenesis processes can generate solution crevasses. the gradual downstream increase in the frequency of occurrence of solution crevasses is thought to result from the transport of the downstream sediment figure 4. histogram of quartz surface microtextures in the xuelongnang outburst sediments. at least 10 grains per sample were analyzed. the numbers in the vertical axis of the curve correspond to the structure numbers listed in table 3. g eo lo gi a c ro at ic a geologia croatica 72 / special issue88 in deeper underwater conditions for longer times, which leads to dissolved pits continuing to form solution crevasses. scaling describes a wide range of surface splitting, which has resulted in the fragmented spalling of grains (krinsley & doornkamp, 1973). it is a final product of chemical modification, or the last stage of a chemical effect. it is known to be very rare within the outburst sediment, which may be due to the excessively short effect time, along with falling water levels. dam-burst floods move so fast that there is not enough time to further erode the grains. silica pellicle is deposited as a thin layer of silica on the quartz surfaces. it usually occurs after the formation of silica globules, and silica flowers are the third phase of silica precipitation. also, it usually covers other shallow mechanical microtextures, which leads to greater difficulties in the recognition of some of the characteristics. when silica has enough time to precipitate under water, silica pellicles can be formed. however, dam burst processes are very rapid, which makes them unable to meet this requirement. therefore, silica pellicles are very rare within outburst sediment. 4.4.3. mechanical and chemical characteristics the relief indicates the smoothness of the grain’s surface and can be subdivided into three categories: low, medium, and high relief. the collision between grains and/or reformation will lead to relief irregularity. generally, low and medium relief are formed in diagenetic environments. however, in some special cases, such as in dam burst environments, they can be generated by dissolution processes and precipitation. for example, dissolution and precipitation can erase or fill relief. therefore, low and medium relief tend to range from sparse to common among outburst sediments, while little high relief has been observed. chatter marks are large curved grooves on grain surfaces, which lack clear splitting phenomena (peterknecht & tietz, 2011). usually, they are the product of mixing actions, including mechanical actions, passive collisions, and chemical reactions during the processes of sediment transport. therefore, a particular sedimentary environment cannot be identified by their appearance (bull, 1981; peterknecht & tietz, 2011; table 3). the only possible conclusion is that they are associated with underwater effects. adhering particles are all the fragments or grains attached to the surface of the quartz grains, of which the compositions and sizes are variable (higgs, 1979). they have extensive sources, including parent rock, other mineral grains, or diagenetic products. however, the adhering particles are easily destroyed and could not provide enough accurate information. as a result, this percentage change played a limited role in this study and can only provide a supplementary method on the diamicton discrimination. 5. conclusions it has been found that dam-burst flooding induces special gravel fabric characteristics, variable particle size distributions, and significant damage to the quartz grains. in this study, in accordance with the distance from the residual dam, the sediments were divided into three sections: upstream, midstream, and downstream. the gravel fabric characteristics were found to be consistent with the short-term strong explosive high-flow hydrodynamic conditions of dam-burst flooding, of which the tendency of plane ab was close to the river’s trend, with a dip angle generally greater than 35°. the laser granularity test showed that almost no clay minerals could be detected in the samples of outburst sediment. these findings confirmed that the sediments were not mixed with the landslide-lake sediment and had not undergone a long static ambient environment. the present results indicate that each section of sediment had a distinct gravel fabric and particle size distribution. due to the gradual reduction in stream capacity from the dam-burst mouth to the downstream areas, it was concluded that gravel size increased with proximity to the residual dam. the particle size distribution showed a similar decrease in grain size with distance from the residual dam. therefore, the average particle size value assisted in distinguishing the different environments for each section of sediment, with the larger average particle size showing greater stream capacity, and vice versa. the scanning electron microscopy results showed that the frequency distributions of the surface microtextures for the quartz grains in the outburst sediment were abundant in the case of sub-angular shape category (> 75%); common in the v-shaped percussion cracks, solution crevasses, medium relief, and chatter mark categories (50% to 75%); and rare in the meandering ridge, underwater polished surface, large conchoidal fracture (> 100 μm), directional etch pit, and crystalline overgrowth categories. also, no imbricate grinding features or scaling were apparent in any of the samples. especially, the frequency percentages of the various microtextures in each section of the sediment showed a gradual change rule. in some cases, they were found to increase with distance from the residual dam, as in the case of v-shaped percussion cracks, which indicated that the hydrodynamics had gradually reduced. such characteristics can potentially be used to identify outburst sedimentary environments. however, fluctuations were determined to exist in the other characteristics, such as the solution crevasses. this may have been due to the participation of a late fluvial effect which induced complex conditions. it was interesting to note that some of the characteristics were reduced, such as adhering particles. alternatively, the collisions between the grains of the samples closer to the residual dam were more frequent, which led to more impact debris becoming attached to the grains’ surfaces. the quartz grains from the outburst sediment are compared with the grains from underwater, aeolian, and glacial sediments etc (table 3), which provide an identification basis for outburst sedimentary deposits. these mesoscopic and microscopic works reveals sedimentary characteristics of the landslide-dam outburst deposits, indicating an obvious change of transport processes. acknowledgement this study was supported by the national natural science foundation of china (grants no. 41571012 and no. 41230743) and the national key r&d program of china (grant no. 2018yfc1505003). we sincerely thank the editor and the anonymous reviewers for their comments which substantially improved the manuscript. references bull, p.a. (1981): environmental reconstruction by electron microscopy.– progress physical geography, 5/3, 368–397. doi: 10.1177/030913338100500302 chakroun, a., miskovsky, j.c. & zaghbib-turki, d. (2009): quartz grain surface features in environmental determination of aeolian quaternary deposits in northeastern tunisia.– mineralogical magazine, 73/4, 607–614. doi: 10.1180/minmag.2009.073.4.607 chen, r.c., chen, j., ma, j.x. & cui, z.j. (2019): quartz grain surface microtextures of dam-break flood deposits from a landslide-dammed lake: a case study.– sedimentary geology, 383, 238–247. doi: /10.1016/j.sedgeo.2019.02.010 chen, j. & cui, z. (2015): discovery of outburst deposits induced by the xuelongnang paleolandslide-dammed lake in the upper jinsha river, china and its environmental and hazard significance.– acta sedimentologica sinica, 33/2, 275–284 (in chinese,with english abstr.). g eologia c roatica chen et al.: meso/micro-texture analysis of the landslide-dam outburst sediments in the upper jinsha river, se tibetan plateau 89 chen, j., dai, f., lv, t. & cui, z. (2013): holocene landslide-dammed lake deposits in the upper jinsha river, se tibetan plateau and their ages.– quaternary international, 298, 107–113. doi: 10.1016/j.quaint.2012.09.018 chen, j., zhou, w., cui, z.j., li, w.c., wu, s. & ma, j.x. (2018): formation process of a large paleolandslide-dammed lake at xuelongnang in the upper jinsha river, se tibetan plateau: constraints from osl and 14 c dating.– landslides, 15, 2399–2412. doi: 10.1007/s10346-018-1056-3 costa, p.j.m., andrade, c., dawsn, a.g., mahaney, w.c., freitas, m.c., paris, r. & taborda, r. (2012): microtextural characteristics of quartz grains transported and deposited by tsunamis and storms.– sedimentary geology, 275, 55–69. doi: 10.1016/j.sedgeo.2012.07.013 costa, p.j.m., andrade, c., mahaney, w.c., marques da silva, f., freire, p., freitas, m. c., janardo, c., oliveira, m.a., silva, t., lopes, v. (2013): aeolian microtextures in silica spheres induced in a wind tunnel experiment: comparison with aeolian quartz.– geomorphology, 180–181, 120–129. doi: 10.1016/j.geomorph.2012.09.011 folk, r.l. (1980): petrology of sedimentary rocks.– hemphill press, austin, texas, 170 p. hamilton, w. & krinsley, d.h. (1967): upper palaeozoic glacial deposits of south america and southern australia.– geological society america bulletin, 78/6, 783–799. helland, p.e., diffendal, r.f., helland, p.e. & diffendal, r.f. (1993): probable glacial climatic conditions in source areas during deposition of parts of the ash hollow formation, ogallala group (late tertiary), of western nebraska.– american journal science, 293/8, 744–757. doi: 10.2475/ajs.293.8.744 higgs, r. (1979): quartz-grain surface features (texture) of mesozoic-cenozoic sands from the labrador and western greenland continental margins.– journal sedimentary petrology, 49/ 2, 599–610. immonen, n. (2013): surface microtextures of ice-rafted quartz grains revealing glacial ice in the cenozoic arctic.– palaeogeography, palaeoclimatology, palaeoecology, 374, 293–302. doi: 10.1016/j.palaeo.2013.02.003 kenig, k. (2006): surface microtextures of quartz grains from vistulian loesses from selected profiles of poland and some other countries.– quaternary international, 152–153/15, 118–135. doi: 10.1016/j.quaint.2005.12.015 kleesment, a. (2009): roundness and surface features of quartz grains in middle devonian deposits of the east baltic and their palaeogeographical implications.– estonian journal earth sciences, 58/1, 71–84. doi: 10.3176/earth.2009.1.07 krinsley, d.h. (2011): atlas of quartz sand surface textures.– cambridge university press, cambridge, 91 p. krinsley, d.h. & takahashi, t. (1962): applications of electron microscopy to geology.– new york academy science transactions, 25/1, 3–22. doi: 10.1111/j.2164-0947.1962.tb03509.x luo, h., wu, f., wang, d., chang, j., bao, h., xu, j. & ma, a. (2015): physical and mechanical properties of malan loess at zhaojiaan landslide area.– journal engineering geology, 23/1, 44–51(in chinese, with english abstr.). ma, j.x., chen, j., cui, z.j., zhou, w., liu, c., guo, p. & shi, q. (2018): sedimentary evidence of outburst deposits induced by the diexi paleolandslidedammed lake of the upper minjiang river in china.– quaternary international, 464, 460–481. doi: 10.1016/j.quaint.2017.09.022 mahaney, w.c. (1992): quartz particle types in chinese and european loesses.– naturwissenschaften, 79/6, p. 266. doi: 10.1007/bf01175391 mahaney, w.c. (2002): atlas of sand grain surface textures and applications.– oxford university press, new york, 237 p. mahaney, w.c. & andres, w. (1991): glacially crushed quartz grains in loess as indicators of long-distance transport from major european ice centers during the pleistocene.– boreas, 20/3, 179–192. doi: 10.1111/j.1502–3885.1991.tb00153.x mahaney, w.c. & andres, w. (1996): scanning electron microscopy of quartz sand from the north-central saharan desert of algeria.– zeitschrift geomorphologie n.f., supplement-bd, 103, 179–192. mahaney, w.c. & kalm, v. (1995): scanning electron microscopy of pleistocene tills in estonia.– boreas, 24/1, 13–29. doi: 10.1111/j.1502-3885.1995.tb00624.x mahaney, w.c. & kalm, v. (2000): comparative scanning electron microscopy study of oriented till blocks, glacial grains and devonian sands in estonia and latvia.– boreas, 29/1, 35–51. doi: 10.1111/j.1502-3885.2000.tb01199.x mahaney, w.c., claridge, c. & campbell, i. (1996): microtextures on quartz grains in tills from antarctica.– palaeogeography, palaeoclimatology, palaeoecology, 121/1, 89–103. doi: 10.1016/0031-0182(95)00069-0 mahaney, w.c., stewart, a. & kalm, v. (2001): quantification of sem microtextures useful in sedimentary environmental discrimination.– boreas, 30, 165–171. doi: 10.1111/j.1502-3885.2001.tb01220.x mahaney, w.c., vortisch, w. & julig, p., (1988): relative differences between glacially crushed quartz transported by mountain and continental ice: some examples from north america and east africa.– american journal science, 288/8, 810-826. doi: 10.2475/ajs.288.8.810 molen, m.o. (2014): a simple method to classify diamicts by scanning electron microscope from surface microtextures.– sedimentology, 61/7, 2020-2041. doi: 10.1111/sed.12127 peterknecht, k.m. & tietz, g.f. (2011): chattermark trails: surface features on detrital quartz grains indicative of a tropical climate.– journal sedimentary research, 81/1-2, 153–158. pye, k. (1983): grain surface textures and carbonate content of late pleistocene loess from west germany and poland.– journal sedimentary petrology, 53/3, 973–980. smalley, i.j. & glendinning, s. (1991): two distinct particle types in the lanzhou loess.– naturwissenchaften, 78/4, p. 167. doi: 10.1007/bf01136203 stuut, j.w., temmesfeld, f. & deckker, p.d. (2014): a 550 ka record of aeolian activity near north west cape, australia: inferences from grain-size distributions and bulk chemistry of se indian ocean deep-sea sediments.– quaternary science reviews, 83/1-2, 83–94. doi: 10.1016/j.quascirev.2013.11.003 vos, k., vandenberghe, n. & elsen, j. (2014): surface textural analysis of quartz grains by scanning electron microscopy (sem): from sample preparation to environmental interpretation.– earth-science reviews, 128/1, 93–104. doi: 10.1016/j.earscirev.2013.10.013 whalley, w.b. & krinsley, d.h. (1974): a scanning electron microscope study of surface textures of quartz grains from glacial environments.– sedimentology, 21/1, 87–105. doi: 10.1111/j.1365-3091.1974.tb01783.x g eo lo gi a c ro at ic a geologia croatica 72 / special issue90 plate 1 photomicrographs of the quartz grains. a – sub-angular grains with v-shaped percussion cracks (upstream sediment) b – sub-angular grains with impact pits (upstream sediment) c – photomicrograph of a v-shaped percussion crack with adhering particles (downstream sediment) d – v-shaped percussion cracks with residual conchoidal fractures at the top-right corners (downstream sediment) e – disc concave pit (downstream sediment) f – disc concave pit with a v-shaped pit at the bottom right corner (downstream sediment) g eologia c roatica chen et al.: meso/micro-texture analysis of the landslide-dam outburst sediments in the upper jinsha river, se tibetan plateau 91 plate 2. photomicrographs of the quartz grains. a – solution crevasses at different scales (downstream sediment) b – sub-angular grains with underwater polished surfaces (downstream sediment) c – sub-angular grains with vague impact marks (upstream sediment) d – photomicrograph of chatter marks (downstream sediment) e – photomicrograph of adhering particles on the striations (midstream sediment) f – photomicrograph of adhering particles on the straight steps (downstream sediment) 2021 | 74/1 | 41–56 | 9 figs. | 3 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the lower miocene macelj formation was described and mapped in eastern slovenia and the northwestern part of the hrvatsko zagorje basin (hzb) in croatia (šimunić, an. et al., 1995; aničić & juriša, 1984, 1985; aničić et al., 2002; fig. 1a). it was deposited in shallow marine and deltaic sedimentary environments (avanić, 2012) on the southern margin of the eggenburgian central paratethys sea (rögl & steininger, 1983; piller et al., 2007; harzhauser & piller, 2007; pavelić, 2001; kováč et al., 2017), and it reflects specific, mostly tidal depositional conditions. in croatia, it is distributed in the area between mts. strahinščica and ivanščica in the south and ravna gora in the northeast, bounded by the sutla river in the west and bednja in the east (fig. 1a). these deposits are about 300-350 m thick and consist of the so-called macelj sandstones, i.e. glauconitic sandstones, conglomerates, siltstones, pelites and pyroclastics (šimunić, an. et al., 1995). the macelj fm. was subdivided into three members based on detailed analysis of measured geological columns and mapping; the vučji jarek mb, the čemernica mb. and the lipni vrh mb. (šimunić, an. et al., 1995). more recent researches proposed a further member, i.e. the vrbno mb. (avanić et al., 2005; avanić, 2012) and as such, they were represented on recent geological maps (fig. 2) tidal deposits in the early miocene central paratethys: the vučji jarek and čemernica members of the macelj formation (nw croatia) radovan avanić1, davor pavelić2, zoltan pécskay3, mirjana miknić1, darko tibljaš4 and lara wacha1 1 croatian geological survey, department of geology, sachsova 2, hr-10000 zagreb, croatia 2 university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, hr-10000 zagreb, croatia 3 institute for nuclear research, isotope climatology and environmental research centre (icer), k-ar group, bem tér 18/c 4026, hu-4030 debrecen, hungary 4 university of zagreb, faculty of science, horvatovac 95, hr-10000 zagreb, croatia doi: 10.4154/gc.2021.06 abstract the macelj formation is an informal eggenburgian-early ottnangian lithostratigraphic unit that is established in the area of the hrvatsko zagorje basin, which represented a marginal zone of the early miocene central paratethys sea. modern studies, as a part of the geologic map of the republic of croatia 1:50 000 project, yielded new data that improves the knowledge of the depositional and stratigraphic characteristics of the formation. the sedimentological research within this study was focused on the two older lithostratigraphic units of the macelj formation: the vučji jarek member and the čemernica member. the vučji jarek mb. is represented by three facies. the facies of horizontally bedded sandstones is characterized by mostly medium-grained, moderately sorted sandstones that reflect deposition on the foreshore to the upper shoreface. the facies of horizontally and cross-bedded glauconitic sandstones is composed of fineto coarsegrained, well-sorted sandstones that indicate foreshore to shoreface deposition under tidal influence. the facies of horizontally and cross-bedded pyroclastics consists of tuff, pumice, lapilli and large blocks, showing a chaotic structure in places. deposition occurred at the shoreface under tidal influence. the čemernica mb. is represented by the facies of structureless clayey-silty sands that are poorly sorted and bioturbated, and indicates deposition below the fairweather wavebase, in the offshore-transition zone. deposits of the members include marine macroand microfossil associations. k-ar dating of separated glauconite mineral fractions yielded an early eggenburgian age for the vučji jarek mb. glauconitic sandstones (19.2±0.64 ma) which is in accordance with biostratigraphical analyses. sedimentological characteristics of the eggenburgian macelj fm., especially those that reflect the tidal influence, fit the general characteristics of the central paratethys sea in the early miocene. (avanić et al., 2015). based on the fossil association, deposits of the macelj fm. belong to the eggenburgian-early ottnangian (šimunić, an. et al., 1995; avanić, 2012). nevertheless, systematic geochronological studies are still lacking. an accurate geochronological study based on radiometric dating might be expected to provide a better understanding related to such a sedimentary sequence and would be of significance to understanding the regional distribution of similar early miocene deposits in the central paratethys. the macelj formation has been the subject of many studies. in pioneering works, dominating sandstones were interpreted as shallow marine deposits, and named the macelj sandstones (gorjanović-kramberger, 1904a, b). later, a mineralogical study of the macelj sandstones indicated the origin of glauconitic material with the alteration of dacite-andesite volcanoclastic material in shallow-marine environments (tišljar & šimunić, 1978; šimunić, al. et al., 1990; tadej et al., 1997), while the provenance of the sandstones, interpreted as shallow marine deposits, was related to the suture belts, back-arc thrusted belts or magmatic arcs (aljinović et al., 2003). sedimentological studies suggested the macelj sandstones indicated deposition by the influence of tides (šimunić, al. et al., 1988, 1990; avanić et al., 2005; avanić, 2012). article history: manuscript received june 02, 2020 revised manuscript accepted february 16, 2021 available online february 28, 2021 keywords: macelj formation, vučji jarek member, čemernica member, tidal deposits, k-ar dating, eggenburgian, hrvatsko zagorje basin, central paratethys g eo lo gi a c ro at ic a geologia croatica 74/142 the aim of this paper is to interpret the depositional mechanisms and environments of the vučji jarek mb. and čemernica mb. as the two older members of the macelj fm., based on facies analysis, and reconstruction of the early miocene palaeogeography of the hzb. within this study geological mapping at the scale of 1:50.000 of the area between the slovenian border and strahinščica and ivanščica mts. in nw croatia was performed accompanied with detailed sampling and analysis of most representative locations and outcrops (fig. 2). a new geologic map is presented, with lithostratigraphic units categorized according to lithostratigraphic standards proposed by korbar et al. (2012). furthermore, for the first time, the chronological framework for the glauconite rich sediments is given and discussed based on k-ar dating applied to the separated monomineralic glauconite fraction. in addition, based on the presented data, their interpretation and geochronology, the formalisation of the vučji jarek, and čemernica members and the formalization of the macelj fm. itself is proposed, in accordance with salvador (1994) and korbar et al. (2012). adverse field circumstances, including relatively small outcrops scattered throughout the hzb, and partially weathered deposits limited detailed studies in some places and resulted in a more general interpretation. however, the interpretation of the depositional environments and palaeogeographic reconstruction of the macelj fm., together with new geochronologic data, will improve the knowledge of the sedimentary evolution of this part of the central paratethys, and enable regional sedimentological and stratigraphic correlation in the early miocene. figure 1. a location map showing the nw part of croatia. the study area is marked in yellow. the inset shows the geographic sketch of the mediterranean area. the territory of croatia is shaded and the study area is marked with a yellow dot. b palaeogeographic sketch map of the circum-mediterranean area with a focus on the central paratethys sea in the burdigalian-eggenburgian (modified after harzhauser & piller, 2007) and the tentative position of the hrvatsko zagorje basin (i.e. hrvatsko zagorje bay – hzb). g eologia c roatica avanić et al.: tidal deposits in the early miocene central paratethys: the vučji jarek and čemernica members of the macelj formation (nw croatia) 43 fi gu re 2 . a g eo lo gi ca l m ap o f t he n w p ar t o f c ro at ia . m od ifi ed a ft er a va n ić e t a l. ( 20 15 ). le g en d : a q 2a llu vi al se di m en ts : g ra ve ls, sa nd s, si lts a nd c la ys ; v ra -v ra pč e fm .: b io ca lc ar en ite s a nd b io ca lc ru di te s; ve j-v ej al ni ca fm .: f os si lif er ou s m ar ls w ith sa nd st on e in te rla ye rs ; c rk -c rk ov ec fm .: s an ds w ith la m in iti c m ar ls a nd g ra ve ls ; b ed -b ed nj a fm .: c al ci tic si lts to ne s, sa nd s a nd tu ffs ; m ac el j f m . ( vr bvr bn o m b. : s an ds to ne s, sa nd s, ca lc iti c si lts , t uff s a nd b en to ni tic c la ys ; l iv -l ip ni v rh m b. : co ng lo m er at es , s an ds to ne s a nd sa nd s; če m -č em er ni ca m b. : g la uc on iti c cl ay ey -s ilt y sa nd s; vu j-v uč ji ja re k fm .: h or iz on ta l a nd c ro ss -b ed de d sa nd st on es a nd tu ffs ); g ol -g ol ub ov ec fm .: c on gl om er at es , s an ds to ne s, si lts , m ar ls, a nd es ite s, tu ffs an d ch ao tic p yr oc la st ic b re cc ia s; m el j-m el ja ni fm .: m ar ls a nd s ilt st on es w ith s an ds to ne s an d sa nd s an d cl ay ey li m es to ne s; e 2 ,3 /t -n eo ge ne b as em en t: eo ce ne li m es to ne s an d tr ia ss ic li m es to ne s an d do lo m ite s; 1. a ss um ed /c ov er ed n or m al ge ol og ic b ou nd ar y; 2 . a ss um ed /c ov er ed e ro si on al b ou nd ar y; 3 . a ss um ed /c ov er ed o ve rt ur ne d ge ol og ic b ou nd ar y; 4 . a ss um ed /c ov er ed fa ul t; 5. a ss um ed /c ov er ed re ve rs e fa ul t; 6. d ex tr al s tr ik esl ip fa ul t; 7. s tr ik e an d di p of b ed di ng . t he lo ca tio ns o f t he m ea su re d co lu m ns a re m ar ke d in a th ic k re d lin e an d sp ot s: lit ho st ra tig ra ph ic c ol um ns m ac -6 a nd m ac -7 (m ac el j-6 a nd m ac el j-7 ), vu j ( vu čj i j ar ek ), za k12 (z ag or sk a ko pr iv ni ca -1 -2 ) a nd q d j ( q ua rr y d on je je se nj e) . g eo lo gi a c ro at ic a geologia croatica 74/144 2. geological setting during the miocene, the connection of the central paratethys with the world sea was established and lost several times. marine transgressions, especially during the early miocene, did not flood the entire basin. this caused deposition in different environments characterized by a salinity change and evolution of endemic species, so the specific central paratethys evolution has necessitated the establishment of regional miocene stages (fig. 3a) (báldi, 1980; rögl & steininger, 1983; rögl, 1996, 1998; popov et al., 2004; harzhauser & piller, 2007; piller et al., 2007; sant et al., 2017; kováč et al., 2018). in the early miocene, the central paratethys was connected with the western tethys (i.e. the mediterranean) and the north sea and was mostly characterized by marine deposition (báldi, 1980; rögl & steininger, 1983; rögl, 1998; popov et al., 2004; harzhauser & piller, 2007; kováč et al., 2018). the eggenburgian deposition was controlled by an anti-estuarine water regime, when evaporation exceeded the fresh-water input from precipitation and river discharge (kováč et al., 2017). the hrvatsko zagorje basin (hzb), situated in north-western croatia (fig. 1a and b), is an early miocene marginal sedimentary basin and an integral part of the central paratethyan realm (pavelić, 2001; avanić, 2012; pavelić & kovačić, 2018). after the disintegration of the western tethys into the paratethys and the mediterranean in the late eocene (báldi, 1980; rögl & steininger, 1983; rögl, 1996, 1998), a large area of north croatia became land. sedimentation continued to the oligocene (i.e. kiscellian, after báldi, 1969; rögl & steininger, 1983; piller et al., 2007) only in northwestern croatia (šimunić, an. et al., 1981, 1982). after tectonic uplift, a new depositional cycle commenced in the egerian-eggenburgian, characterized by the transition from marine to brackish-water and back again to marine deposition, that was restricted to the nw part of croatia, i.e. the hzb, the mura depression and the nw part of the drava depression (pavelić, 2001; avanić, 2012). the early miocene deposition of the hzb strongly differs from the rest of north croatia, i.e. from the rift-type north croatian basin (ncb), where sedimentation commenced in the ottnangian and was characterized by fresh-water environments that passed into marine deposition in the early or middle badenian (pavelić, 2001; ćorić et al., 2009; malvić, 2012; pavelić & kovačić, 2018; avanić et al., 2018a, b; brlek et al., 2018, 2020). the evolution of the hzb was strongly controlled by volcanism and several phases of tectonic activity. along relics of the previous subduction zone, periadriatic-vardar transform faults were generated during the oligocene transpression phase, controlling the formation of the southern margin of the central paratethys. the early miocene (egerian-eggenburgian) volcanism was the first post-subduction volcanic activity controlled by the easternmost prolongation of the periadriatic line (pamić et al., 1995; sachsenhofer et al., 2001; fodor et al., 2008; fodor, 2019; kováč et al., 2018). the late early to middle middle miocene basin was characterized by extensional tectonics, while compression affected the basin at the middle/late miocene boundary, and from the pliocene to the quaternary. the tectonics created the modern structural pattern characterized by uplifted blocks and counterclockwise rotation (tomljenović & csontos, 2001; márton et al., 2002, 2006). the geological mapping of the hzb established informal early miocene lithostratigraphic units that are considered as formations. the meljani fm. and golubovec fm. belong to the egerian, the macelj fm. belongs to the eggenburgian and the early ottnangian while the bednja fm. is late eggenburgian to ottnangian in age. the early miocene lithostratigraphic division ends with the karpatian crkovec fm. (fig. 3b) (avanić, 2012; avanić et al., 2018a). figure 3. a chronostratigraphy of the central paratethys (modified after piller et al., 2007). b a simplified lithostratigraphy of the oligocene, the early miocene and the middle miocene in the study area (avanić, 2012). the position of the measured lithostratigraphic columns has been added. g eologia c roatica avanić et al.: tidal deposits in the early miocene central paratethys: the vučji jarek and čemernica members of the macelj formation (nw croatia) 45 3. methods the fieldwork included detailed, decimetre-scale measuring and sampling of most representative geological sections and individu al outcrops of the vučji jarek and čemernica mbs. sediments, and geological mapping of the wider area. where possible, measurements of the geometry of the depositional units were performed and dimensions of the sedimentary structures were recorded along with facies analysis in the field, in order to interpret depositional mechanisms and environments. unconformities indicated by abrupt facies changes and their lateral extent were measured in order to define major bounding surfaces. indications of palaeotransport directions were studied for further discussion on the source of the material. samples were collected for sedimentological and petrographic analyses with the aim of determining their composition and their provenance. four samples of glauconitic material-rich sediments were collected for k-ar dating to establish their age. two were taken from the vučji jarek mb. glauconitic sandstones (6b/1 and 6b/2), and two from the clayey-silty sands from the čemernica mb. (mac-6 and mac-7) (fig. 2). due to glauconite sensitivity to direct sunlight (odin, 1982), locations in the shade, fresh and northward oriented outcrops were selected for sampling. in accordance with the higher content of glauconitic material (1.4-3.7 wt%) in the sandstones of the vučji jarek mb. compared to the sediments of the čemernica member (0.2-2.3 wt%), up to 11 kg of sample material was taken for the former sandstone unit and up to 20 kg for the latter (avanić, 2012). to obtain a pure glauconitic mineral fraction, the samples underwent several cycles of processing. the sandstone samples were crushed to 1 mm diameter, treated with 10% ch3cooh to remove carbonates, sieved and mechanically scrubbed to remove clay coatings. glauconitic mineral fractions were separated using the frantz type magnetic separator and heavy liquid (bromoform) separation. finally, the purity of the glauconite fractions was improved by hand-picking under the microscope. x-ray powder diffraction (xrpd) analysis was performed to test the purity of the glauconite separates, and to determine the maturation stage of glauconite in the different samples. xrpd patterns were recorded using the philips vertical x-ray goniometer (type x’ pert) equipped with a cu-tube (40 kv, 40 ma) and graphite monochromator. ir-spectra were recorded on a perkin elmer spectrum one instrument at the faculty of chemistry and technology in split using kbr pressed discs. the samples were dated at the k-ar laboratory of the institute for nuclear research (atomki) in debrecen (hungary). experimental details of the k-ar method described in balogh (1985) were slightly modified for argon measurements. approximately 0.15 g of the pure glauconitic samples were wrapped in aluminium foil and a copper sieve. the samples were preheated before radiogenic argon extraction, with the aim of decreasing atmospheric argon contamination. the results of the experiments demonstrate that in the case of evolved to high-evolved glauconites containing at least 6% potassium, a general bake-out temperature as high as 180°c is needed, in order to guarantee complete retention of the radiogenic argon. consequently, all the glauconitic samples were baked out at the chosen temperature of 180°c, over 10-12 hrs under a pressure of 10-6 torr. argon was extracted under ultra-high vacuum conditions by radio-frequency induction heating and fusion of rock samples in mo crucibles. the extracted gas was purified using a ti sponge and saes st 707 type getters, to remove chemically active gas contaminants and some liquid nitrogen in a cold trap to remove condensable gases. argon concentrations were measured by an 38ar isotope dilution mass spectrometric method, previously calibrated with atmospheric argon and international rock standards. argon isotope ratios have been normalised to atmospheric argon, accepting 295.5 for the (40ar/36ar)atm ratio. potassium was determined by flame photometry with a na buffer and li internal standard using a corning m480 type flame photometer. the k-ar age of the glauconitic samples is calculated using the decay constants suggested by steiger & jäger (1977). analytical error is given at the 68% confidence level (1s). 4. results and interpretation 4.1. facies analysis and petrography a 325 m thick geological sequence was measured at 6 individual locations in the investigated area, which were correlated based on lithological characteristics, fossil content, k-ar dating results, superposition and geological mapping data (fig. 4). within the clastic-carbonate and pyroclastic deposits of the vučji jarek mb. and čemernica mb. of the macelj fm., four sedimentary facies associations were distinguished and described. the facies associations are mostly of complex composition and are named based on the prevailing facies. they are as follows: facies of horizontally bedded sands (f1), facies of horizontally and cross-bedded glauconitic sandstones (f2), facies of horizontally and cross-bedded pyroclastics (f3), and facies of structureless clayey-silty sands (f4). although deposits of facies f1 and f2 are similar, they are distinguished in some details for a better lithostratigraphic correlation for geological mapping, particularly the possibility of defining lower-ranking lithostratigraphic units in the future. an overview of the facies described is given in table 1. 4.1.1. vučji jarek member 4.1.1.1. facies of horizontally bedded sandstones (f1) the facies of horizontally bedded sandstones (f1) occurs in the upper part of the zagorska koprivnica-1 (zak-1) and the zagorska table 1. an overview of the lithostratigraphic units of the macelj formation. the given thicknesses are measured in the field. the spatial distribution of lithostratigraphic units is given in the geological map (fig. 2). macelj formation member facies lithological characteristics thickness (m) environment čemernica f4 structureless clayey-silty sands structureless clayey-silty sands, rare horizontal and cross-lamination, poorly sorted, bioturbation, microfauna <225 offshore-transition vu čj i j ar ek f3 horizontally and cross-bedded pyroclastics tuff, pumice, lapilli, large blocks, mostly horizontal bedding, rare cross-bedding, chaotic pyroclastics with slumps 50 <2 00 shoreface (subtidal) f2 horizontally and cross-bedded glauconitic sandstones horizontally and cross-bedded sandstones, horizontal lamination, fineto coarse grained, well sorted, mud drapes, molluscs 2–200 foreshore to shoreface (subtidal) f1 horizontally bedded sandstones horizontally bedded and rare cross-bedded sandstones, wavy and horizontal lamination, mostly medium grained, moderately sorted 64 foreshore to upper shoreface g eo lo gi a c ro at ic a geologia croatica 74/146 koprivnica-2 (zak-2) sections (fig. 4). these deposits overlie egerian marine to brackish deposits of the golubovec fm. (fig. 5a), and are overlain by the facies of horizontally and cross-bedded glauconitic sandstones (f2). laterally, they are correlatives of the lower part of the f2 facies. the contacts between the two facies were not visible at the outcrop. the maximum thickness of the deposits is about 54 m (fig. 4). the f1 is represented mostly by more or less lithified horizontally bedded sandstones, with bed thicknesses between 1 and 10 cm. bedding planes are sharp. some beds show irregular wavy lamination that exhibits a lateral figure 4. detailed lithostratigraphic columns and correlation. see fig. 2 for the locations of the lithostratigraphic columns, and fig. 3b for their chronostratigraphic position. g eologia c roatica avanić et al.: tidal deposits in the early miocene central paratethys: the vučji jarek and čemernica members of the macelj formation (nw croatia) 47 figure 5. deposits of the vučji jarek mb. a the yellow line shows the erosional and transgressive contact between horizontally bedded sandstones (f1) of the vučji jarek mb. (above) and sands with silts of the golubovec fm. (below) in the zak-1 section (figs. 2 and 4) b cross-bedding (marked with yellow line) in the facies of horizontally and cross-bedded glauconitic sandstones (f2) in the vuj section (figs. 2 and 4) c the contact between tangential cross-bedded sandstone (above the hammer) and horizontally laminated sandstones (hammer level). detail of the facies of horizontally and cross-bedded glauconitic sandstones (f2) at the level of 44th m of the vučji jarek section (fig. 4). d detail of the horizontal lamination in the f2 facies (hammer level on fig. 5c). e wide and flat troughs in a section nearly perpendicular to the transport direction in glauconitic sandstones of the f2 facies at the locality of osredečki (fig. 2). f the quarry in the pyroclastics in the donje jesenje (figs 2 and 4). well developed bedding is visible. g in the central part of the photo, dark grey clastics of devitrified pumice from the f3 facies is observed as an indication of synsedimentary explosive volcanic activity in the donje jesenje quarry (figs. 2 and 4.) h chaotic pyroclastics with large clasts of f3 facies indicating the proximity of the volcano in the upper part of the donje jesenje quarry (fig. 4). g eo lo gi a c ro at ic a geologia croatica 74/148 transition to horizontal lamination. cross-bedding rarely occurs. the sandstones are mostly medium-grained and moderately sorted. in the medium-grained sandstone, silt intraclasts occur. in the upper part of the zak-1 section (fig. 4), fine-grained sandstones overlie medium-grained sandstones, in places forming small-scale fining upwards cycles. in the lower part, the cycles are composed of coarse-grained sandstone, which includes limonitic silty sand intraclasts with an erosional lower bedding plane. sandstones of the f1 facies consist of quartz, lithic particles mostly represented by tuff and volcanic glass, feldspars and glauconite. staurolite, tourmaline, garnet and zircon predominate in the heavy mineral fraction1. varying grain-sizes in the sandstones indicate deposition by fluctuating strong and weak currents while shallow marine molluscs suggest a marine depositional environment (avanić, 2012). in the marine depositional environment, such deposits were probably accumulated by traction currents (allen, 1984; howard & reineck, 1981) in the foreshore and upper shoreface as indicated by horizontal and wavy lamination and crossbedding (fig. 6) (clifton et al., 1971; leithold & bourgeois, 1984; cheel, 1990; summarized in dashtgard et al., 2012). small-scale fining upwards cycles can be a result of relative sea level rise in the nearshore. the mineralogical composition of sandstones indicates a permanent supply of terrestrial material while the 64 m thickness of f1 suggests a relatively longlasting shallow water environment. 4.1.1.2. facies of horizontally and cross-bedded glauconitic sandstones (f2) the facies of horizontally and cross-bedded glauconitic sandstones (f2) was measured on the vučji jarek section (figs. 4 and 5b-e). deposits of f2 are overlain by deposits of the facies of structureless clayey-silty sands (f4) (fig. 4). the contact between the facies is not exposed. the thickness of the f2 deposits reaches 138 m (fig. 4). the horizontally bedded sandstones (fig. 5d) predominate over the cross-bedded sandstones (figs. 4 and 5b). they are generally thicker (range 120 cm) than similar deposits of the f1 facies. the cross-bedding shows the planar, tangential (fig. 5c) and trough (fig. 5b) types. the planar and tangential cross-bedded sets are 0.1 to 3.5 m thick, while the trough cross1 šimunić, al. (1990): sedimentno-petrografske analize. geološka karta 1:50.000, potprojekt-4.– fond struč. dok., hrv. geol. instituta, zagreb, zagreb. bedded sets range from 0.5 to 1.5 m. individual troughs within sets are up to 12 m wide. occasionally mud drapes up to a few mm thick can occur. sets are separated by horizontally bedded and laminated sandstones. sandstones are fineto coarse-grained and well sorted. their colour is greyish to greenish due to the glauconite which is more concentrated in some laminae. the grains are pelletand “kidney-”shaped with a cryptocrystalline to microcrystalline and flaky structure, determined as the poorly crystalized dioctahedral mica illite, celadonite or glauconite2. except for the glauconite grains, quartz, lithic particles and feldspars prevail in the sandstone composition, while chlorite, muscovite and biotite rarely occur (šimunić, al. et al., 1988). the feldspars are represented by microcline, oligoclase and andesine. the lithic particles are represented by metamorphic rock fragments (quartzite, and quartz, mica, sericite and chlorite schists), altered volcanics, felsic intrusives (granite and pegmatite), tuffs, cherts, carbonates and shales (šimunić, al. et al., 1990). the carbonate particles are composed of dolomite and skeletal fragments of marine organisms. translucent minerals prevail within the heavy mineral fraction, represented by tourmaline, zircon, apatite, staurolite, rutile, epidote and amphibole. the sandstone is cemented by a mixture of quartz, dolomite and calcite with rare amounts of matrix (šimunić, al. et al., 1990). the sandstones are determined as glauconitic lithic arenites, graywackes and glauconitic graywackes (šimunić, an. et al., 1995). a mollusc assemblage was observed mostly composed of pectenid remains. several species were recognized including aequipecten? northamptoni oblita michelotti, aequipecten macrotis sowerby, aequipecten? cf. darnoensis csepreghymèznerics, gigantopecten ex gr. holgeri (geinitz), flabellipecten ex gr. burdigalensis (lamarck), pecten sp., p. psudobeudanti deprét & roman, gastrana fragilis gracilis schaffer3,4. the marine macrofossil association indicates the eggenburgian age (sensu mandic & steininger, 2003). 2 prohić, e. (1988): rezultati rentgenskih analiza. geološka karta 1:50.000, potprojekt 4.– fond struč. dokument. igi, zagreb, 193/88. 3 šikić, k. (1991): makropaleontološke analize.– fond struč. dok., hrv. geol. instituta, zagreb, zagreb. 4 šikić, k. (2004): makropaleontološke analize uzoraka na pot pro jektu „klastično-karbonatni kompleks neogena hrvatskog zagorja”. projekt geološka karta rh 1:50.000.– fond struč. dok., hrv. geol. instituta, zagreb, zagreb. figure 6. sedimentation model of the vučji jarek mb. and the čemernica mb. g eologia c roatica avanić et al.: tidal deposits in the early miocene central paratethys: the vučji jarek and čemernica members of the macelj formation (nw croatia) 49 measurements of the planar cross-beds foreset orientation at the vučji jarek section indicate a palaeotransport direction towards 27°, i.e. towards the north-northeast (fig. 4). the palaeotransport direction was also measured on the cross-bedded glauconitic sandstones exposed at outcrops and during geological mapping (fig. 2). all measurements indicate a general northwest to northeast direction, with an average value of 352°, i.e. basinwards according to central paratethys palaeogeographic reconstructions (fig. 1b) (popov et al., 2004; harzhauser & piller, 2007; kováč et al., 2017). the fossil association documents a shallow marine environment. the horizontal lamination suggests deposition in the upper flow regime while the cross-lamination indicates deposition by traction (allen, 1984; howard & reineck, 1981) probably in the shoreface surf to the foreshore swash zone (fig. 6) (clifton et al., 1971; leithold & bourgeois, 1984; swift et al., 1987). the planar, tangential and trough cross-bedding suggest deposition probably by 2d and 3d subaqueous bedforms. the 1.5 m thick troughs indicate migration of large dunes by strong currents (ashley, 1990). the palaeotransport generally towards to the north, i.e. basinwards, and mud drapes indicate deposition by ebb currents suggesting of a shoreface dominated by tides, where the bedforms comprised sandwaves (allen, 1980: visser, 1980; dalrymple, 1992; nio & yang, 1991; desjardins et al., 2012; longhitano et al., 2014), in accordance with earlier interpretations (šimunić, al. et al., 1988, 1990; avanić et al., 2005; avanić, 2012). similar to the f1 facies, the composition and the thickness of f2 indicate a strong terrestrial influence and nearshore deposition with a tidal influence during a relatively long period. 4.1.1.3. facies of horizontally and cross-bedded pyroclastics (f3) the facies of horizontally and cross-bedded pyroclastics (f3) was studied in detail in the donje jesenje quarry (figs. 4 and 5f-h). geological mapping indicated that deposits of the f3 facies represent a lense within deposits of the f2 facies and are laterally correlative with the upper part of the f2. the contact with overlying deposits is not visible. these pyroclastic deposits form a 52.5 m thick succession (fig. 4). they are mostly horizontally bedded, and demonstrate a bed thickness that usually varies between 1 and 30 cm. occasionally, amalgamated beds were discovered, reaching a thickness up to 5 m. trough cross-bedded pyroclastics of sandy grain-size were recognized in a few beds. in the f3 facies, tuffs prevail, exhibiting vertical alternation of vitric, vitric-crystal, crystal and crystal-lithic types (golub & brajdić, 1969; šimunić, al. et al., 1988). pumice characterized by voids that are irregularly dispersed or parallel to the bedding plane is intercalated within the pyroclastics (fig. 5g). the voids are either empty or are infilled with clayish material produced by devitrification of volcanic glass (tibljaš & šćavničar, 2007). various clay minerals, zeolites (clinoptilolite, mordenite and analcime), feldspars and sio2 phases were determined as the result of devitrification processes (tibljaš, 1996; tibljaš & šćavničar, 1988, 2007). in the vitric and crystal tuffs, volcanic glass shards, and crystal grains of feldspar (andesine) and biotite predominate, while amphiboles and quartz are present in smaller amounts. in varieties where biotite is more abundant within the tuff matrix, besides glass shards, microcrystalline quartz, zeolites, chlorite, magnetite and feldspar, microlites were determined (šimunić, al. et al., 1990). the lithic tuffs are mostly composed of tuff and effusive rock particles, followed by mineral porphyroclasts and glass shards. vitric tuffs contain a low alkali and iron content, while the crystal tuffs contain a significantly higher amount of alkalis, aluminium and iron (golub & brajdić, 1969). based on the sio2 content (6570%), the tuffs were determined as dacite-andesite types (golub & brajdić, 1969). in the lower and the upper part of the succession, chaotic pyroclastics with slumps occur (figs. 4 and 5h). they consist of tuffs with dispersed lapilli fragments composed of volcanic glass, and lithic and crystal particles. the lithoclasts are mostly andesite or tuff clasts. rarely rounded tuff blocks up to 5 m in diameter occur. the uppermost part of the succession is characterized by tuffs that are strongly affected by recent weathering processes that resulted in their alteration into a sandy material. deposition of the pyroclastics probably took place in an aquatic depositional environment as indicated by pumice with voids formed parallel to bedding planes that reflects the rapid cooling of volcanic ash in water, and by relatively quick settling on the bottom (fig. 7) (whitham & sparks, 1986; mcphie et al., 1993; cas & wright, 1995). the association with defigure 7. facies of structureless clayey-silty sands (f4) of the čemernica mb. at the čemernica section (figs. 2 and 4). a deposits are composed of a poorly sorted mixture of sand-, siltand clay-sized material. bedding is not developed probably due to bioturbation. b erosional boundary (yellow line) between structureless clayey-silty sands (f4) of the čemernica mb. (below) and the weathered conglomerates and sandstones of the lipni vrh mb. (above) at the macelj-6 section ( figs. 2 and 4). g eo lo gi a c ro at ic a geologia croatica 74/150 posits of facies f2 suggests shallow marine deposition. the material was probably reworked by strong upper shoreface traction currents that formed horizontal beds (fig. 7). the shallow water deposition is supported by cross-bedded pyroclastics. they suggest subaqueous dune migration probably by tides on the shoreface, similar to cross-bedded sandstones of the f2 facies (clifton et al., 1971; leithold & bourgeois, 1984; ashley, 1990; nio & yang, 1991). the absence of mixing with the shoreface siliciclastic material is probably a consequence of the proximity of the volcano. chaotic pyroclastics in the lower and upper part of the succession are interpreted as a result of slumping generated by seismic shocks that caused liquefaction and destabilization of the pyroclastic material (sensu cas & wright, 1995). the significant thickness of the deposits implies relatively long-lasting explosive volcanic activity. this activity was characterized by its variable intensity. intense volcanism produced the crystalline tuff and a high accumulation of pumice, while quieter volcanism resulted in vitric tuff and low accumulation of pumice (šimunić, al. et al., 1988; mcphie et al., 1993). the lateral correlation of the pyroclastics with deposits of the f2 facies indicates the eggenburgian age of the explosive volcanic activity. 4.1.2. čemernica member 4.1.2.1. facies of structureless clayey-silty sands (f4) the facies of structureless clayey-silty sands (f4) was studied at the macelj-6 and macelj-7 localities (fig. 2). the deposits of f4 overlie the f2 facies but the direct contact is not exposed in the studied area. the sands are erosively overlain by conglomerates of the lipni vrh mb. (fig. 7b) that belong to the upper part of the macelj fm. (avanić, 2012). the measured thickness of the f4 deposits is 18 m and consists of a 17 m thick sandy unit overlain by a 1 m thick horizontally and planar cross-bedded sandstone unit. the sandy unit is characterized by intense burrowing that produced the structureless poorly sorted mixture of sand-, silt and clay-sized particles (fig. 7a). ichnofossils and marl intraclasts are abundant in the unit. rare horizontal lamination and cross-lamination that occur in the top bed indicate primary structures. the composition of the light mineral fraction is characterized by the predominance of quartz over lithoclasts and k-feldspars, while glauconite grains rarely occur 5,6 (šimunić, an. et al., 1995). in the heavy minerals fraction translucent grains prevail, among which garnet is the most abundant, while tourmaline, staurolite and rutile are less common. the caco3 content is 12.3–17 wt%. sands are more lithified in places than others, hence their mineral composition is more similar to the f2 deposits. they are composed of quartz of volcanic origin, feldspars, chloritized biotite, volcanic glass shards, tuff and volcanic rocks, with a lower glauconitic content compared to the f2 facies. this is also evident in their colour which is more yellowish to greenish or greyish to yellowish (šimunić, an. et al., 1995; aljinović et al., 2003). in the sediments of facies f4, the following microfaunal assemblage was determined: semivulvulina pectinata (reuss), spirorutilus carinatus (d`orbigny), elphidium subtypicum 5 grizelj, a. (2004a): sedimentno-petrografske analize uzoraka s geo loškog kartiranja (2002). projekt geološka karta rh 1:50.000.fond struč. dok., hrv. geol. instituta, zagreb, zagreb. 6 grizelj, a. (2004b): sedimentno-petrografske analize uzoraka s prospekcijskih točaka (2003). projekt geološka karta rh 1:50.000.fond struč. dok., hrv. geol. instituta, zagreb, zagreb. papp, e. crispum (linne), e. ortenburgense (egger), cibicidoides sp., c. budayi cicha & zapletalova, heterolepa praecincta (karrer) and h. dutemplei (d`orb.)7. along with the mentioned foraminifera, in a further study lenticulina inornata (d`orb.), l. cultrata (montfort), bolivina fastigia cushman, fontbotia wuellerstorfi (schwager) and pullenia bulloides (d`orb.) were determined. a fossil shell mold of anadara sp. was also observed8. the cibicidoides-heterolepa group is usually related to oxic conditions, spirorutilus carinatus implies an increased nutrient input, while the less abundant lenticulina sp. and bolivina sp. indicate suboxic conditions at the bottom of the sea. such an assemblage originates from the offshore area (rögl & spezzaferri, 2003; spezzaferri et al., 2004). palynological analyses9 yielded a small number of spores including ?cicatricosisporite sp., as well as the dinocysts ?homotryblium sp. and operculodinium sp. associations that includes elphidium ortenburgense (egger) indicates the central paratethys eggenburgian age of the deposits of the f4 facies (piller et al., 2007; pippèrr & reichenbacher, 2009), although some recent studies indicate the possibillity of an ottnangian (grunert et al., 2012; pipperr et al., 2018) or karpatian age (harzhauser et al., 2017). palaeoecological characteristics of the faunal association indicate a marine environment where prevailing fine-grained deposits and common bioturbation suggest deposition from suspension and low energy conditions, probably below the fair weather wave base. cross-lamination in the uppermost sand indicates ripple migration, i.e. deposition by traction (allen, 1968). such currents might be generated by a storm that affected the coast causing reworking and redeposition of the beach material below the fair-weather wave-base, in the offshore-transition zone ( fig. 7) (kumar & sanders, 1976; bourgeois, 1980; bourgeois & leithold, 1984). the clayey-silty sand that shows intensive bioturbation might reflect organic activity during fair weather. the prevailing siliciclastic material suggests a strong terrestrial influence on deposition. 4.2. k-ar dating results and chronology of the macelj formation in order to reconstruct the evolution of the sedimentary history of the study area, and for better correlation of studied sediments with similar early miocene deposits in the central paratethys, four representative glauconite-rich samples were selected for dating: mac-6 and mac-7 (čemernica mb.) and 6b/1 and 6b/2 (vučji jarek mb.) (fig. 2). the analytical data and the dating results are summarised in tables 2 and 3. the chronostratigraphic timescale of central paratethys compiled by piller et al. (2007) was used for the correlation and interpretation of the obtained k-ar ages. to test whether the glauconitic separates from the representative samples from the čemernica and vučji jarek mbs. are suitable for dating they were analysed in more detail. xrpd analyses 7 šikić, l. (1988): izvještaj o mikropaleontološkim analizama s po dru čja sjeverozapadne hrvatske. geološka karta sfrj 1:50 000, potprojekt 4.fond struč. dok., hrv. geol. instituta, zagreb, zagreb. 8 šikić, k., (2004): makropaleontološke analize uzoraka na potpro jek tu „klastično-karbonatni kompleks neogena hrvatskog zagorja”. projekt geološka karta rh 1:50.000.fond struč. dok., hrv. geol. instituta, zagreb, zagreb. 9 bakrač, k. (2004): palinološke analize za zadatak: klastično-karbo nat ni kompleks neogena hrvatskog zagorja, projekt geološka karta rh 1:50.000. fond struč. dok., hrv. geol. instituta, zagreb, zagreb. g eologia c roatica avanić et al.: tidal deposits in the early miocene central paratethys: the vučji jarek and čemernica members of the macelj formation (nw croatia) 51 showed that no impurities were present in the separated glauconitic material and that excellent separates were obtained, providing reliable material for k-ar dating. furthermore, the recorded patterns show that the investigated glauconitic material differ significantly (fig. 8). the diffraction pattern obtained from sample mac6 representing the čemernica mb. has broader diffraction maxima, best seen on the 001 peak, indicating a higher expandable layer content. observed d(001) values, 10.65 å for the mac6 sample and 10.26 å for the 6b/1 sample, are in accordance with this statement and indicate the presence of 16 and 6 % of expandable layers, respectively (tab. 2). lower intensities of poorly resolved (in contrast to 6b/1 sample) 1128 and 112 peaks also indicate that glauconite in the mac 6 sample is less evolved. the observed d(060) of 1.511 å for the mac6 sample, compared to the 1.516 å peak from the 6b/1 sample representing the vučji jarek mb., possibly indicates a higher al content in the octahedral sheet of the former sample (radoslovich, 1962). this is in accordance with observed ir spectra. even though the ir spectra of both samples are characterized by poorly resolved broadened bends, they differ in the appearance of the oh-stretching region. čemernica mb. samples have more pronounced bands at 3603 and 3625 cm-1, which can be ascribed to al-mg and al-al cationic environments of the oh groups, respectively (besson & drits, 1997), in addition to bands at 3557 (mg-fe3+ and al-fe2+) and 3530 cm-1 (fe3+-fe3+) which are practically the only visible ones in the vučji jarek sample. such xrpd results are in accordance with the k2o content in the analysed samples obtained by flame photometry (tab. 2). the glauconitic materials from the vučji jarek mb. have a higher k20 content (7.75-8.03%) compared to those from the čemernica mb. (5.58-6.24%). based on the k2o content (tab. 2) glauconites mac-6 and mac-7 (čemernica mb.) can be classified as slightly evolved to evolved glauconite, while samples 6b/1 and 6b/2 (vučji jarek mb.) can be classified as evolved to highly-evolved glauconite (odin & dodson, 1982; odin, 1982). according to the relation given by velde & odin (1975) these values, in accordance with xrd data (tab. 2), indicate that the content of the expandable layers in glauconitic materials from vučji jarek and čemernica samples is approximately 5-6 and 19-25%, respectively. it is known that the basis for the formation of authigenic glauconite on the sea floor is the initial substrate, which consists of various components including quartz, silica, mica, feldspars, clay minerals, phosphates, aragonite, calcite, pyroclastic material and others (odin & dodson, 1982). the exchange of these components takes place within the substrate, which leads to the growth of glauconitic material in the pores. in the samples studied, glauconitic material is present as a psudomatrix between quartz grains therefore it can be presumed that it is formed in situ (fig. 9). in the present study, it was not possible to determine table 2. k2o content, determined by flame photometry, d001 and expandable layers %, determined by xrpd, in glauconitic separates from the macelj fm. formation member column sample k2o (%) d001 (å) expandable layers (%) macelj (mac) vučji jarek (vuj) vučji jarek (vuj) 6b/1 7.75 10.26 6 6b/2 8.03 10.18 5 čemernica (čem) macelj-6 mac-6 6.24 10.65 16 macelj-7 mac-7 5.58 10.94 23 table 3. k and 40ar content and the corresponding k-ar isotopic age of glauconitic materials of the macelj fm. sample k (%) 40ar rad (%) 40ar rad *10-6 (cc/stp/g) k-ar (ma) 6b/1 6.44 44.3 5.696 22.62 ± 0.86 6b/2 6.67 61.4 5.005 19.21 ± 0.64 mac-6 5.18 55.1 4.535 22.38 ± 0.77 mac-7 4.63 51.2 4.189 23.14 ± 0.82 figure 8. xrpd patterns of glauconitic materials from samples 6b/1 and mac-6 belonging to the vučji jarek and čemernica members respectively. 001, 1129, 112 and 060 peaks are indexed (cu kα radiation). see text for the explanation. g eo lo gi a c ro at ic a geologia croatica 74/152 which type of initial substrate was transformed into glauconitic material. however, according to aljinović et al. (2003), glauconitic material in the intergranular pores of the oldest sandstones in the macelj fm. resulted from the transformation of the primary matrix, which was related to volcanic material deposited directly from the air into the basin. for other sandstones, they suggest erosion of volcanic rocks located in the source area i.e. the volcanic material can be older than the host sediments. tadej et al. (1997) in their study of glauconitic material from the macelj sandstones observed that there are differences, not only between glauconitic material from three different locations (not the same as in the present study) but also between glauconitic material from the same sandstone sample. they also noticed that in the same sample glauconitic material occurs in two basic forms; as detrital grains and as the matrix material. an analytical error value is given to the apparent age of each specific sample (tab. 3). this analytical error may be used for comparison of the significance of the individual age results in this study, but has hardly any statistical value. it should be noted that the precision of the analysis is limited by the potassium determinations, which were made on a split of the dated sample by flame photometry and is dependent of the inhomogeneity of the powdered sample. as a consequence, the “sampling error” can be more significant than the analytical error. table 3 shows that there is a considerable spread in age values, ranging from 19.2±0.64 ma to 23.1±0.82 ma. however, the ages seem to reflect two different events; an “older episode” (23.1-22.4 ma) and a “younger one” (at about 19.2 ma). the ages of 22.4±0.77 ma, 23.1±0.82 ma and 22.6±0.86 ma obtained from samples mac-6, mac-7 and 6b/1, respectively, are in excellent agreement and consistent within errors (table 3). such agreeable data are especially significant since the dated samples come from a well-defined stratigraphic position. however, the potassium analyses for these samples exhibit a highly different concentration of potassium. this could be due to the inhomogeneity of the samples. in that case, the measured ages are probably overestimated and do not indicate the timing of the deposition, it could rather imply the recycling of detrital glauconite from older sedimentary rocks, without completely resetting and obtaining an equilibrium with the depositional environment. such discordant k-ar ages are believed to result from the incorporation of varying amounts of “inherited” 40ar from older sedimentary units. in the case of čemernica samples, the much lower potassium content is the result of the fact that glauconitic material contains a higher content of expandable layers (it is only slightly-evolved to evolved). according to odin & fullaghar (1988), glauconitic materials that are not highly evolved are usually characterized by the inheritance of radiogenic isotope and show a higher age, so the ages obtained on these samples should be taken with caution. furthermore, it should also be noted that the mobility of potassium in the altered glauconites often results in k-ar data that are too old i.e. overestimated (the obtained analytical age is older than the real geological age). finally, the youngest obtained age of 19.21±0.64 ma (sample 6b/2) can be regarded as the geological age of the sediment, because it is also supported by stratigraphic, mineralogical (glauconite with the lowest expandable layer content present as a pseudomatrix), geochemical (the highest potassium content i.e. the most evolved material among the investigated) and chronological arguments. in the absence of other suitable geochronometers in the case of such pure glauconite and despite the analytical difficulties, the obtained k-ar age can be reliably used for correlation with similar deposits. so, the k-ar dating of glauconitic deposits of the vučji jarek mb. is in accordance with biostratigraphic analyses that indicate their eggenburgian age. 5. discussion 5.1. vertical succession and sea level changes marine deposits of the macelj fm. represent the middle part of the lower miocene sequence in the hzb as indicated by stratigraphic dating and geological mapping. they are underlain by marine to brackish deposits of the golubovec fm., and are overlain by marine offshore to nearshore deposits of the bednja fm. and the crkovec fm. (fig. 3b). the macelj fm., that consists of the vučji jarek mb., čemernica mb., lipni vrh mb. and vrbno mb. (fig. 3b), indicates dynamic deposition in a changeable marine nearshore environment. the vučji jarek mb., which is composed mostly of sandstones and pyroclastics, reflects beach to shoreface deposition that was affected by tides. deposits of the čemernica mb. that is composed mostly of clayey-silty sands, were interpreted as an offshore-transition zone. the lipni vrh mb. that consists of deltaic conglomerates and sandstones (šimunić, an. et al., 1995), interfingers with the čemernica mb., and transgressively overlies older rocks. in the vertical succession, the vučji jarek mb. belongs to the lower part of the eggenburgian macelj fm. the contact with the older, egerian golubovec fm., is erosional and transgressive. this implies a relatively short emersion at the end of the egerian that was followed by a transgression and subsequent deposition in a shallow sea in the early eggenburgian. the return to a new marine environment was followed by increasing volcanic activity as indicated by pyroclastics of the f3 facies. the upper part of the vučji jarek mb. interfingers with the lower part of the čemernica mb. (fig. 3b). the čemernica mb. belongs to the middle part of the macelj fm. and probably to the middle-late eggenburgian. its deposits partly interfinger with and overlie the glauconitic sandstones (f2) of the upper part of the vučji jarek mb. (fig. 3b). they also transgressively cover the early egerian marine meljani fm. (figs. 2 and 3b) that is characterized by littoral carbonate rocks overlain by prodelta marls and sandstone intercalations (avanić et al., 2018a,b). deposits of the čemernica mb. are overlain by the fan delta and shoreface conglomerates and sandstones of the late eggenburgian lipni vrh mb. (fig. 3b). these deposits represent figure 9. a photomicrograph of glauconitic sandstone of the vučji jarek member, locality 6b (plane polarized light). glauconite (green) is present between the quartz grains (white) in the form of a pseudomatrix. g eologia c roatica avanić et al.: tidal deposits in the early miocene central paratethys: the vučji jarek and čemernica members of the macelj formation (nw croatia) 53 the upper part of the macelj fm. the conglomerates and sandstones intercalate within the upper part of the čemernica mb. where they form a 10 m thick lens (figs. 2 and 3b). finally, the macelj fm. terminates with tidal to subtidal sands, marls, bentoni te clays and pyroclastics of the late eggenburgian to the early ottnangian vrbno mb. (fig. 3b) (avanić et al., 2018a). furthermore, the calcareous siltstones, silty sands, pyroclastics and gravels of the ottnangian marine nearshore bednja fm. cover the top of the čemernica mb. (figs. 2 and 3b) indicating the continuation of early miocene marine deposition in the hzb (avanić, 2012; avanić et al., 2018a). geological mapping indicated that deposits of the vučji jarek and čemernica members are thickest in the western part of the investigated area where they reach up to 400 m (fig. 3b) suggesting high accommodation in the hzb. their thickness decreases towards the east. the vertical succession of the vučji jarek and čemernica members indicates a gradual change from a more coarse-grained deposition into a more fine-grained deposition as a consequence of deepening of the environment from the shoreface into the offshore-transition zone. the subsequent coarse-grained deposits of the lipni vrh mb. reflect a new shallowing phase of the environment (fig. 3b). so, deposits of the macelj fm. indicate sea level changes and represent a marine transgressive-regressive sequence that formed during the eggenburgian into the early ottnangian. the sea level changes are not correlative with the eustatic sea level changes that indicate three 3rd order transgressive-regressive sequences in the early miocene (sensu hardenbol et al., 1998). 5.2. regional correlation of the lithostratigraphic units deposits of the vučji jarek and čemernica members can be correlated with similar eggenburgian deposits in the central paratethys. first of all, deposits of the vučji jarek mb. transgressively overlie older rocks that is a characteristic of the central paratethys realm where the erosional gap was frequently developed at the base of the eggenburgian and the basal sediments reflect a transgressive pattern (rögl & steininger, 1983; mandic et al., 2004; piller et al., 2007). lithologically, deposits of the vučji jarek mb. and the čemernica mb. are correlative with the lower miocene quartz sands, sandstones and conglomerates with sandy clay intercalations in the western prolongation of the hzb in ne slovenia (buser, 1977; aničić & juriša, 1984; jelen & rifelj, 2002), and with the lower miocene deposits in ne austria associated with the eggenburgian group (steininger & senes, 1971). within the eggenburgian group, shallow marine sands of the burgschleintz formation with clayey sands and clays of the kühnring member (mandic & steininger, 2003) can be correlated with deposits of the macelj fm. and the čemernica mb., respectively, from nw croatia. furthermore, there is a significant similarity of the vučji jarek and čemernica members deposits with the glauconitic sandstones of the eggenburgian pétervására sandstone formation from the northeastern segment of the north hungarian bay. there, crossbedded sandstones interpreted as sandwaves indicated subtidal deposition with dominant ebb currents towards the north, similar to the hrvatsko zagorje basin (sztanó, 1995; sztanó & de boer, 1995; sztanó & józsa, 1996; báldi, 2009; szőcs & hips, 2018). moreover, the alpine foreland basins were also characterized by tidally controlled deposits in the eggenburgian (allen et al., 1985). the explosive volcanic activity in the hrvatsko zagorje basin is another common characteristic that is correlative with the central paratethys in the eggenburgian as the volcanism affected a large area of the realm (slávik et al., 1968; kaličiak et al., 1989; roetzel, 1994; nehyba & roetzel, 1999; pamić et al., 2002; pécskay et al., 2006). the correlation indicates that the development of the western-southwestern part of a restricted shallow epicontinental sea of the hrvatsko zagorje basin, dominated by siliciclastic deposition and strong influence of tidal currents, fits with the general characteristics of the central paratethys in the eggenburgian. the palaeogeographic position of the study area (sensu popov et al., 2004; harzhauser & piller, 2007; kováč et al., 2017) suggests deposition in the relatively shallow southern bay of the central paratethys in the eggenburgian, i.e. in the hrvatsko zagorje bay. 6. conclusions 1. the eggenburgian-early ottnangian macelj formation consists of four members: the vučji jarek mb., the čemernica mb., the lipni vrh mb. and the vrbno mb. 2. the vučji jarek mb. is composed of three facies that formed in a shallow sea. the facies of horizontally bedded sandstones (f1) reflects deposition on the foreshore to the upper shoreface under the tidal influence. the facies of horizontally and cross-bedded glauconitic sandstones (f2) belongs to the foreshore to the shoreface zone strongly affected by tides. the facies of horizontally and cross-bedded pyroclastics (f3) formed in the shoreface. 3. the čemernica mb. is represented by the facies of structureless clayey-silty sands (f4) of the offshore-transition zone. deposition was influenced by tides in the hrvatsko zagorje bay that represented a marginal sedimentary basin of the central paratethys sea. 4. k-ar dating of separated glauconite mineral fractions yielded an early eggenburgian age of the vučji jarek mb. glauconitic sandstones (19.2±0.64 ma) that confirms biostratigraphic analyses. 5. deposits of the macelj fm. represent a marine transgressiveregressive sequence that is not correlative with the eustatic sea level changes in the early miocene. 6. the erosional gap in the base of the vučji jarek mb., the prevalence of siliciclastics, the shallow marine environment, the influence of tides on the deposition and the synsedimentary volcanic activity, all fit the general characteristics of the central paratethys sea and its palaeogeography in the eggenburgian. 7. we propose formalizing the four members described within this paper, as well as the macelj formation itself. acknowledgement this research is a part of the long-term project basic geological map of the republic of croatia at the scale of 1:50.000 financed by the ministry of science of croatia (mzo; project number 1811811096-1093) and the croatian geological survey. it was also supported by the european union and the state of hungary and co-financed by the european regional development fund (ginop-2.3.2-15-2016-00009 ‘icer’), in part by the croatian science foundation under the project ip-2019-04-7042 (sedbas) and by the university of zagreb. special thanks to jožica zupanič and the neogene mapping team (antun šimunić, ivan hećimović, marijan kovačić, davor vrsaljko and damir slovenec) for their support during this research. our thanks also go to oleg mandic for kindly checking the fossils g eo lo gi a c ro at ic a geologia croatica 74/154 list. the technical support of nenad kurtanjek, ivo suša and marko budić is gratefully acknowledged. we thank mirka trajanova and the anonymous reviewer for their thoughtful reviews. references allen, j.r.l. (1968): current ripples.– north-holland, amsterdam, 433 p. allen, j.r.l. (1980): sand waves: a model of origin and internal structures.– sediment. geol., 26, 281–328. doi: 10.1016/0037-0738(80)90022-6 allen, j.r.l. (1984): sedimentary structures: their character and physical basis.– developments in sedimentology, 30a, elsevier, 593 p. allen, p.a., mange-rajetzky, m., matter, a. & homewood, p. (1985): dynamic palaeogeography of the open burdigalian seaway, swiss molasse basin.– eclogae geol. helv., 78, 351–381. aljinović, d., jurak, v. & kompar, d. (2003): compositional variations and origin of glauconite-bearing sandstones (macelj formation, nw croatia).– in: vlahović, i. (ed.): 22nd ias meeting of sedimentology, opatija. abstracts book, zagreb, p. 5. aničić, b. & juriša, m. (1984): osnovna geološka karta sfrj 1:100.000, list rogatec l 33-68 [basic geological map of sfry 1:100000, rogatec sheet – in slovenian].– geološki zavod, ljubljana, geološki zavod, zagreb, savezni geološki zavod, beograd. aničić, b. & juriša, m. (1985): osnovna geološka karta sfrj 1:100.000. tolmač za list rogatec l33-68 [basic geological map of sfry 1:100000, geology of the rogatec sheet – in slovenian].– geološki zavod ljubljana in geološki zavod zagreb, savezni geološki zavod, beograd, 76 p. aničić, b., ogorelec, b., kralj, p. & mišić, m. (2002): litološke značilnosti tercijarnih plasti na kozjanskem. lythology of tertiary beds in kozjansko, eastern slovenia.– geologija, 45, 213–246. ashley, g.m. (1990): classification of large scale subaqueous bedforms: a new look at an old problem.– j. sediment. petrol., 60, 160–172. avanić, r. (2012): litostratigrafske jedinice donjeg miocena sjeverozapadne hrvatske [lower miocene lithostratigraphic units from north-western croatia – in croatian]. – unpubl. phd thesis, faculty of science, university of zagreb, 162 p. avanić, r., pécskay, z., wacha, l. & palinkaš, l. (2005): k-ar dating of glauconitic sediments in macelj mt. (nw croatia).– in: velić, i., vlahović, i. & biondić, r. (eds.): 3. hrvatski geološki kongres, opatija, knjiga sažetaka, zagreb, 5–6. avanić, r., šimunić, an., hećimović, i., kovačić, ma., marković, s., grgasović, t., kurečić, t., slovenec, d. & vrsaljko, d. (2015): osnovna geološka karta rh 1:50000, list trakošćan (ptuj 2) [basic geological map of rh 1:50000, geology of the trakošćan (ptuj 2) sheet – in croatian].– hrvatski geološki institut, zavod za geologiju, zagreb. avanić, r, kovačić, m., pavelić, d. & peh, z. (2018a): the neogene of hrvatsko zagorje.– in: tibljaš, d., horvat, m., tomašić, n., mileusnić, m. & grizelj, a. (eds.): 9th mid-european clay conference, conference book field trip guide book, zagreb, 128–129. avanić, r., šimunić, an. & peh, z. (2018b): geology of the croatian zagorje region.– in: rman, n., marković, t. & brenčić, m. (eds.): 5. slovenski geološki kongres, post congress field trip book, ljubljana, p. 35. báldi, t. (1969): the oligo-miocene stages of the middle paratethys area and the egerian formations in hungary.– ann. univ. sci., sect. geol., 12, 19–28. báldi, t. (1980): a korai paratethys története.– földtani közlöny, 110, 456–472. báldi, t. (2009): kelet-mátrai oligo–miocén rétegsorok paleoklimatológiai és ökológiai elemzése az antarktiszi oligo–miocén jégtakaró változásainak nyomai a paratethysben.– földtani közlöny, 139, 131–150 (in hungarian). balogh, k. (1985): k/ar dating of neogene volcanic activity in hungary. experimental technique, experience and methods of chronological studies.– atomki reports d/1, debrecen, 277–288. besson, g. & drits, v.a. (1997): refined relationships between chemical composition of dioctahedral fine-grained mica minerals and their infrared spectra within the oh stretching region. part i: identification of the oh stretching bands.– clay. clay. miner., 45, 158–169. doi: 10.1346/ccmn.1997.0450204 bourgeois, j. (1980): a transgressive shelf sequence exhibiting hummocky stratification: the cape sebastian sandstone (upper cretaceous), southwestern oregon.– j. sediment. petrol., 50, 681–702. doi: 10.1306/212f7ac2-2b24-11d78648000102c1865d bourgeois, j. & leithold, e.l. (1984): wave-worked conglomerates – depositional processes and criteria for recognition.– in: koster, e.h. & steel, r.j. (eds.): sedimentology of gravels and conglomerates. mem. can. soc. petrol. geol., 10, 331–343, canada. brlek, m., iveša, lj., brčić, v., santos, a., ćorić, s., špišić, m., avanić, r., devescovi, m., pezelj, đ., mišur, i., miknić, m. & johnson, m. e. (2018): rocky-shore unconformities marking the base of badenian (middle miocene) transgression on mt. medvednica basement (north croatian basin, central paratethys).– facies, 64, 1–22. doi: 10.1007/s10347-018-0537-0 brlek, m., kutterolf, s., gaynor, s., kuiper k., belak, m., brčić, v., holcová, k., wang, k.-l., bakrač, k., hajek-tadesse, v., mišur, i., horvat, m., šuica, s. & schaltegger, u. (2020): miocene syn-rift evolution of the north croatian basin (carpathian-pannonian region): new constraints from mts. kalnik and požeška gora volcaniclastic record with regional implications.– int. j. earth. sci., 109, 2775–2880. buser, s. (1977): osnovna geološka karta sfrj 1:100.000, list celje l33-67 [basic geological map of sfry 1:100000, celje sheet – in slovenian].– geološki zavod, ljubljana, savezni geološki zavod, beograd. cas, r.a.f. & wright, j.v. (1995): volcanic successions modern and ancient.-– chapman & hall, 528 p. doi: 10.1007/978-94-009-3167-1 cheel, r.j. (1990): flow, sediment transport and bedform dynamics over the transition from dunes to upper‐stage plane beds: implications for the formation of planar laminae.– sedimentology, 37, 549–553. doi: 10.1111/j.1365-3091.1990.tb00155.x clifton, h.e., hunter, r.e. & phillips, r.l. (1971): depositional structires and processes in the non-barred hugh-energy nearshore.– j. sediment. petrol., 41, 651–670. ćorić, s., pavelić, d., rögl, f., mandić, o., vrabac, s., avanić, r., jerković, l. & vranjković, a. (2009): revised middle miocene datum for initial marine flooding of north croatian basins (pannonian basin system, central paratethys).– geol. croat., 62/1, 31–43. dalrymple, r.w. (1992): tidal depositional systems.– in: walker, r.g. & james, n.p. (eds.): facies models: response to sea level change. geol. assoc. canada, newfoundland, 195–218. dashtgard, s.e., maceachern, j.a., frey, s.e. & gingras, m.k. (2012): tidal efects on the shoreface: towards a conceptual framework.– sediment. geol., 279, 42–61. desjardins p.r., buatois, l.a., pratt, b.r. & mángano, m.g. (2012): sedimentological–ichnological model for tide‐dominated shelf sandbodies: lower cambrian gog group of western canada.– sedimentology, 59, 1452–1477. doi: 10.1111/j.1365-3091.2011.01312.x fodor, l., gerdes a., dunkl, i., koroknai, b., pécskay, z., trajanova, m., horváth, p., vrabec, m., jelen, b., balogh, k. & frisch, w. (2008): miocene emplacement and rapid cooling of the pohorje pluton at the alpinepannonian-dinaridic junction, slovenia.– swiss j. geosci., 101, 255–271. doi: 10.1007/s00015-008-1286-9 fodor, l. (2019): results, problems and future tasks of palaeostress and fault-slip analyses in the pannonian basin: the hungarian contribution.– földtani közlöny, 149, 297–326. doi: 10.23928/foldt.kozl.2019.149.4.297 golub, lj. & brajdić, v. (1969): piroklastične stijene kod donjeg jesenja (hrvatsko zagorje) [pyroclastic rocks from the donje jesenje (hrvatsko zagorje) – in croatian with english summary].– geol. vjesnik, 22, 411–422. gorjanović-kramberger, d. (1904a): geologijska prijegledna karta kraljevine hrvatske-slavonije 1:75.000, list rogatec-kozje [overwiev geological map of kingdom of croatia and slavonia 1:75000, rogatec-kozje sheets – in croatian] zona 21, col. xii.– naklada kraljevske zemaljske vlade, odjel za unutarnje poslove, zagreb. gorjanović-kramberger, d. (1904b): geologijska prijegledna karta kraljevine hrvatske-slavonije 1:75000. tumač za list rogatec-kozje [overwiev geological map of kingdom of croatia and slavonia 1:75000, geology of the rogatec-kozje sheet – in croatian].– naklada kraljevske zemaljske vlade, odjel za unutarnje poslove, zagreb, 25 p. grunert, p., soliman, a., ćorić, s., roetzel, r, harzhauser, m. & piller, w.e. (2012): facies development along the tide-influenced shelf of the burdigalian seaway: an example from the ottnangian stratotype (early miocene, middle burdigalian).– mar. micropaleontol., 84–85, 14–36. doi: 10.1016/j.marmicro.2011.11.004 hardenbol, j., thierry, j., farley, m.b., jacquin, t., de graciansky, p.-c. & vail, p. (1998): mesozoic and cenozoic sequence chronostratigraphic framework of european basins.– in: graciansky, p.c., hardenbol, j., jacquin, t. & vail, p.r. (eds.): mesozoic and cenozoic sequence stratigraphy of european basins. sepm spec. publ., 60, charts 1–8. doi: 10.2110/pec.98.02.0003 harzhauser, m. & piller, w.e. (2007): benchmark data of a changing sea – palaeogeography, palaeobiogeography and events in the central paratethys during the miocene.– palaeoge ogr. palaeoclimatol. palaeoecol., 253, 8–31. doi: 10.1016/j.palaeo.2007.03.031 harzhauser, m., theobalt, d., strauss, p., mandic, o., carnevale, g. & piller, w.e. (2017): miocene biostratigraphy and paleoecology of the mistelhttp://bib.irb.hr/prikazi-rad?&rad=579801 http://bib.irb.hr/prikazi-rad?&rad=207044 http://bib.irb.hr/prikazi-rad?&rad=207044 http://bib.irb.hr/prikazi-rad?&rad=364943 http://bib.irb.hr/prikazi-rad?&rad=364943 http://bib.irb.hr/prikazi-rad?&rad=364943 g eologia c roatica avanić et al.: tidal deposits in the early miocene central paratethys: the vučji jarek and čemernica members of the macelj formation (nw croatia) 55 bach halfgraben in the northwestern vienna basin (lower austria).– jb. geol. b.a., 157, 57–108. howard, j.d. & reineck, h.e. (1981): depositional facies of high-energy beach-tooffshore sequence: comparison with low-energy sequence.– aapg bull., 65, 807–830. jelen, b. & rifelj, h. (2002): stratigraphic structure of the b1 tertiary tectonostratigraphic unit in eastern slovenia.– geologija, ljubljana, 45, 115–138. doi: 10.5474/ geologija.2002.010 kaličiak, m., konečný, v. & lexa, j. (1989): struktúry a v ´yvoj neogénnych vulkanitov slovenska vo vzt’ahu k blokovej tektonike.– geol. práce, spr. 88, 79–103. kumar, n. & sanders, j.e. (1976): characteristics of shoreface storm deposits: modern and ancient examples.– j. sediment. petrol., 46, 145–162. korbar, t., avanić, r., bakrač, k., belak, m., bergant, s., brčić, v., brlek, m., fuček, l., grgasović, t., grizelj, a., halamić, j., hećimović, i., horvat, m., jamičić, d., koch, g., matičec, d., oštrić, n., palenik, d., slovenec, d. & šorša, a. (2012): upute za izradu osnovne geološke karte republike hrvatske m 1:50 000.– hrvatski geološki institut, zagreb, 132 p. kováč, m., hudáčková, n., halásová, e., kováčová, m., holcová, k., oszczypko clowes, m., báldi, k., less, gy, nagymarosy, a., ruman, a., klučiar, t. & jamrich, m. (2017): the central paratethys palaeoceanography: a water circulation model based on microfossil proxies, climate, and changes of depositional environment.– acta. geol. slov., 9, 75–114. kováč, m., halásová, e., hudáčková, n., holcová, k., hyžný, m., jamrich, m. & ruman, a. (2018): towards better correlation of the central paratethys regional time scale with the standard geological time scale of the miocene epoch.– geol. carpath., 69, 283-–300. doi: 10.1515/geoca-2018-0017 leithold, e.l. & bourgeois, j. (1984): characteristics of coarse-grained sequences deposited in nearshore, wave-dominated environments – examples from the miocene of south-west oregon.– sedimentology, 31, 749–775. doi: 10.1111/j.1365-3091.1984.tb00884.x longhitano, s., chiarella, d. & muto, f. (2014): three-dimensional to twodimensional cross-strata transition in the lower plesitocene catanzaro tidal strait transgressive succession (southern italy).– sedimentology, 61, 2136–2171. doi: 10.1111/sed.12138 malvić, t. (2012): review of miocene shallow marine and lacustrine depositional environments in northern croatia.– geol. q., 56, 493–504. doi: 10.7306/gq.1035 mandic, o. & steininger, f.f. (2003): computer-based mollusc stratigraphy – a case study from the eggenburgian (lower miocene) type region (ne austria).– palaeogeogr. palaeoclimatol. palaeoecol., 197, 263–291. doi: 10.1016/s00310182(03)00469-3 mandic, o., harzhauser, m. & roetzel, r. (2004): taphonomy and sequence stratigraphy of spectacular shell accumulations from the type stratum of the central paratethys stage eggenburgian (lower miocene, ne austria).– cour. forsch. inst. senckenberg, 246, 69–88. márton, e., pavelić, d., tomljenović, b., avanić, r., pamić, j. & márton, p. (2002): in the wake of a counterclockwise rotating adriatic microplate: neogene paleomagnetic results from northern croatia.– int. j. earth sci., 91, 514–523. doi: 10.1007/s00531-001-0249-4 márton, e., jelen, b., tomljenović, b., pavelić, d., poljak, m., márton, p., avanić, r. & pamić, j. (2006): late neogene counterclockwise rotation in the sw part of the pannonian basin.– geol. carpath., 57, 41–46. mcphie, j., doyle, m. & allen, r. (1993): volcanic textures.– hobart tas., centre for ore deposits and exploration studies, university of tasmania, 196 p. nehyba, s. & roetzel, r. (1999): lower miocene volcaniclastics in south moravia and lower austria.– jahrb. geol., bund., 141, 473–490. nio, s.d. & yang, c.s. (1991): diagnostic attributes of clastic tidal deposits: a review.– in: smith, d.g., reinson, g.e., zaitlin, b.a. & rahmani, r.a. (eds.): clastic tidal sedimentology. mem. can. soc. petrol. geol., 16, 3–28. odin, g.s. (1982): how to measure glaucony ages.– in: odin, g.s. (ed.): numerical dating in stratigraphy, john wiley & sons, new york, 387–403. odin, g.s. & dodson, m.h. (1982): zero isotopic age of glauconites.– in: odin, g.s. (ed.): numerical dating in stratigraphy, john wiley & sons, new york, 277–305. odin, g.s. & fullagar, p.d. (1988): geological significance of the glaucony facies.– in: odin, g.s. (ed.): green marine clays. developments in sedimentology, elsevier, amsterdam, 45, 295–332. pamić, j., mckee, e., bullen, t.d. & lanphere, m. (1995): geochronology and petrology of tertiar volcanic associations from the southern parts of the pannonian basin.– int. geol. revi., 37, 259–283. pamić, j., balen, d. & herak, m. (2002): origin and geodynamic evolution of late paleogen magmatic associations along the periadriatic-sava-vardar magmatic belt.– geodin. acta, 15, 209–231. pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.– basin res., 13, 359–376. pavelić, d. & kovačić, m. (2018): sedimentology and stratigraphy of the neogene rift-type north basin (pannonian basin system, croatia): a review.– mar. petrol. geol., 9, 455–469. doi: 10.1016/j.marpetgeo.2018.01.026 pécskay, z., lexa, j., szakács, a., seghedi, i., balogh, k., konečný, v., zelenka, t., kovacs, m., póka, t., fülöp, a., márton, e., panaiotu, c. & cvetković, v. (2006): geochronology of neogene–quaternary magmatism in the carpathian arc and intra-carpathian area: a review.– geol. carpath., 57, 511–530. piller, w.e., harzhauser, m. & mandic, o. (2007): miocene central paratethys stratigraphy – current status and future directions.– stratigraphy, 4, 151–168. pippèrr, m. & reichenbacher, b. (2009): biostratigraphy and paleoecology of benthic foraminifera from the eggenburgian “ortenburger meeressande” of southeastern germany (early miocene, paratethys).– n. jb. geol. paläont. abh., 254, 41–61. doi: 10.1127/0077-7749/2009/0003 pippèrr, m., reichenbacher, b., kirscher, u., sant, k. & hanebeck, h. (2018): the middle burdigalian in the north alpine foreland basin (bavaria, se germany) a lithostratigraphic, biostratigraphic and magnetostratigraphic re-evaluation.– newsl. stratigr., 51, 285–309. doi: 10.1127/nos/2017/0403 popov, s.v., rögl, f., rozanov, a.y., steininger, f.f., shcherba, i.g. & kovác, m. (2004): lithological-paleogeographic maps of paratethys. 10 maps, late eocene to pliocene.– cour. forsch.-inst. senckenberg, 250, 1–46. radoslovich, e. (1962): the cell dimensions and symmetry of layer-lattice silicates. ii. regression relations.– am. mineral., 47, 617–636. roetzel, r. (1994): bericht 1993 über geologische aufnahmen im tertiär und quartär im raum grafenberg – maissau auf blatt 22 hollabrunn.– jb. geol. b.-a., 137/3, 435–438. rögl, f. (1996): stratigraphic correlation of the paratethys oligocene and miocene.– mitt. ges. bergbaustud. österr., 41, 65–73. rögl, f. (1998): paleogeographic considerations for mediterranean and paratethys seaways (oligocene to miocene).– ann. naturhist. mus. wien, 99a, 279–310. rögl, f. & steininger, f.-f. (1983): vom zerfall der tethys zu mediterran und paratethys. die neogene palaeogeographie und palinspastik des zirkum-mediterranen raumes.– ann. naturhist. mus. wien, 85, 135–163. rögl, f. & spezzaferri; s. (2003): foraminiferal paleoecology and biostratigraphy of the mühlbach section (gaindorf formation, lower badenian).– ann. naturhist. mus. wien 104a, 23–75. sachsenhofer, r.f., jelen, b., hasenhütll, c., dunkel, i. & rainer, t. (2001): thermal history of tertiary basins in slovenia (alpine-dinaride-pannonian junction).– tectonophysics, 334, 77–99. doi: 10.1016/s0040-1951(01)00057-9 salvador, a. (1994): international stratigraphic guide – a guide to stratigraphic classification, terminology and procedure.– the international union of geological sciences and the geological society of america, boulder, 214. sant, k., palcu, d.v., mandic, o. & krijgsman, w. (2017): changing seas in the early-middle miocene of central europe: a mediterranean approach to paratethyan stratigraphy.– terra nova, 29, 273–281. doi: 10.1111/ter.12273 slávik, j. et al. (1968): tectonics and subsequent volcanism in the western part of east carpathians.– int. geol. congress, rep. of xxiii sess., praha, 2, 61–71. spezzaferri, s., rögl, f., ćorić, s. & hohenegger, j. (2004): paleoenvironmental changes and agglutinated foraminifera across the karpatian/badenian (early/middle miocene) boundary in the styrian basin austria, central paratethys).– in: m. bubik, m. & kaminski, m.a. (eds.): proceedings vi international workshop on agglutinated foraminifera. grzybowski foundation special publication, 8, 423–459. steiger, r.h., & jäger, e. (1977). subcommission on geochronology: convention on the use of decay constants in geoand cosmochronology.– earth planet. sci. lett., 36, 359–362. doi: 10.1016/0012-821x(77)90060-7 steininger, f. & senes, j. (1971): m1 eggenburgien. die eggenburger schichtengruppe und stratotypus. chronostratigraphie und neostratotypen.– vydav. slov. akad. vied, 2, bratislava. swift, d.j.p., hudelson, p.m., brenner, r.l. & thompson, p. (1987): shelf construction in a foreland basin: storm beds, shelf sand bodies, and shelf-slope depositional sequences in the upper cretaceous mesaverde group, book clifs, utah.– sedimentology, 34, 423–457. szőcs, e. & hips, k. (2018): multiphase carbonate cementation in the miocene pétervására sandstone (north hungary): implications for basinal fluid flow and burial history.– geol. carpath., 6, 515–527. doi: 10.1515/geoca-2018-0030 http://bib.irb.hr/prikazi-rad?&rad=584877 http://bib.irb.hr/prikazi-rad?&rad=584877 g eo lo gi a c ro at ic a geologia croatica 74/156 sztanó, o. (1995): palaeogeographic significance of tidal deposits: an example from an early miocene paratethys embayment, northern hungary.– palaeogeogr. palaeoclimatol. palaeoecol., 113, 173–187. doi: 10.1016/0031-0182(95)00054-p sztanó, o. & de boer, p.l. (1995): basin dimensions and morphology as controls on amplification of tidal motions (the early miocene north hungarian bay).– sedimentology, 42, 665–682. doi: 10.1111/j.1365-3091.1995.tb00399.x sztanó, o. & józsa, s. (1996): interaction of basin-margin faults and tidal currents on nearshore sedimentary architecture and composition: a case study from the early miocene of northern hungary.– tectonophysics, 266, 319–341. doi: 10.1016/ s0040-1951(96)00196-5 šimunić, al., šimunić, an., pikija, m. & avanić, r. (1988): utjecaj vulkanizma na sastav “maceljskih pješčenjaka” (sjeverozapadna hrvatska).– in: vujisić, p. (ed.): geološki glasnik posebno izdanje. knjiga vi. zbornik radova vi skupa sedimentologa jugoslavije, cetinje, titograd, 229–243. šimunić, al., avanić, r. & šimunić, an. (1990): „maceljski pješčenjaci” i vulkanizam zapadnog dijela hrvatskog zagorja (hrvatska, jugoslavija).– rad jugosl., akad. znan. umjetn., 449, 24, 179–194. šimunić, an., pikija, m., hećimović, i. & šimunić, al. (1981): osnovna geološka karta sfrj 1:100.000. tumač za list varaždin l 33-69 [basic geological map of sfry 1:100000, geology of the varaždin sheet – in croatian].– institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd, 75 p. šimunić, an., pikija, m. & hećimović, i. (1982): osnovna geološka karta sfrj 1:100.000, list varaždin l 33-69 [basic geological map of sfry 1:100000, varaždin sheet – in croatian].– institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd. šimunić, an., avanić, r., šimunić, al. & hećimović, i. (1995): litostratigrafska raščlamba donjomiocenskih klastita u hrvatskom zagorju.– in: vlahović, i., velić, i. & šparica, m. (eds.): 1. hrvatski geološki kongres, opatija, zbornik radova (proceedings), zagreb, 2, 581–584. tadej, n., slovenec, d., tišljar, j. & inkret, i. (1997): glauconitic materials from lower miocene macelj-sandstones of the hrvatsko zagorje, north-western croatia.– geol. croat. 50, 17–25. tibljaš, d. (1996): zeoliti i drugi produkti alteracijskih procesa u oligocenskim i donjomiocenskim piroklastitima na širem području macelja [zeolites and other products of the alteration processes in the oligocene and early miocene pyroclastic rocks from the macelj area – in croatian, with english summary].– unpubl. phd thesis, faculty of science, university of zagreb, 167 p. tibljaš, d. & šćavničar, s. (1988): mineraloško istraživanje klinoptilolita, plagioklasa i seladonita iz tufa donjeg jesenja u hrvatskom zagorju [mineralogical investigations of clinoptilolite, plagioclase and celadonite in tuff from donje jesenje (hrvatsko zagorje)].– geol. vjesnik, 41, 99–117. tibljaš, d. & šćavničar, s. (2007): nalazište zeolitnog tufa na području krapine.– in: filipan, t., tišma, s. & farkaš, a. (eds.): prirodni zeolitni tuf iz hrvatske u zaštiti okoliša, zagreb, 13–23. tišljar, j. & šimunić, al. (1978): maceljski pješčenjaci (točke 2 i 3).– in: babić, lj. & jelaska,v. (eds.): vodič ekskurzije iii skupa sedimentologa jugoslavije. hrvatsko geološko društvo, zagreb, 37–42. tomljenović, b. & csontos, l. (2001): neogene–quaternary structures in the border zone between alps, dinarides and pannonian basin (hrvatsko zagorje and karlovac basins, croatia).– int. j. earth sci., 90, 560–578. doi: 10.1007/ s005310000176 velde, b. & odin, g.s. (1975): further information related to the origin of glauconite.– clay. clay. miner., 23, 376–381. doi: 10.1346/ccmn.1975.0230509 visser, m.j. (1980): neap-spring cycles reflected in holocene subtidal large-scale bedform deposits: a preliminary note.– geology, 8, 543–546. doi: 10.1130/0091 7613(1980)8%3c543:ncrihs%3e2.0.co;2 whitham, a.g. & sparks, r.s.j. (1986): pumice.– bull. volcanol., 48, 209–224. 2022 | 75/1 | 101–113 | 9 figs. | 4 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the triassic was an important period for the recovery of life on earth after the end-permian extinction. not only were new ecosystems established, but new animal lineages came to play key roles in the emerging modern evolutionary fauna (payne & van de schootbrugge, 2007; benton, 2016; buatois et al., 2016). among such groups were also the actinopterygian fishes (tintori et al., 2014a, b) and marine reptiles (motani, 2009; stubbs & benton, 2016; brayard et al., 2017). the most famous finds of the latter come from the classic deposits of the germanic basin (rieppel, 1999; hagdorn & rieppel, 1999; diedrich, 2012), and the southern alps of the monte san giorgio area (furrer, 1995a; röhl et al., 2001; stockar, 2010; hugi et al., 2011; furrer & vandelli, 2014; renesto et al., 2014; beardmore & furrer, 2016, 2019), as well as from more recently discovered sites in southern china (liu et al., 2011; benton et al., 2013). as recently as 20 years ago, reports of sauropterygians from the triassic beds of slovenia were scarce. deecke (1886) mentioned remains of a marine reptile collected from the scree below mt. storžič in the kamnik-savinja alps. the fossil was later de a sedimentological description of the middle triassic vertebrate-bearing limestone from velika planina, the kamnik-savinja alps, slovenia luka gale1,2(*), tomaž hitij3, blaž vičič4,5, matija križnar6, jure žalohar1,5, bogomir celarc2 and marko vrabec1 1 university of ljubljana, department of geology, aškerčeva 12, 1000 ljubljana, slovenia; (luka.gale@ntf.uni-lj.si; marko.vrabec@ntf.uni-lj.si) 2 geological survey of slovenia, dimičeva 14, 1000 ljubljana, slovenia; (luka.gale@geo-zs.si; bogomir.celarc@geo-zs.si) 3 university of ljubljana, faculty of medicine, dental school, hrvatski trg 6, 1000 ljubljana, slovenia; (tomazhitij@gmail.com) 4 international centre for the theoretical physics, strada costiera 11, i-34151 trieste, italy; 5 quantectum ag, churerstrasse 80, 8808 pfäffikon, switzerland; (jure.zalohar@guest.arnes.si; blaz.vicic@gmail.com) 6 slovenian museum of natural history, prešernova 20, si-1000 ljubljana, slovenia; (mkriznar@pms-lj.si) doi: 10.4154/gc.2022.06 abstract in the kamnik-savinja alps (slovenia), the lower serla dolomite laterally passes into a succession of thinto medium-bedded bituminous limestones of the velika planina member. the finely laminated lower part of this member contains well-preserved actinopterygian fish and sauropterygian remains. the research aimed to determine the sedimentological and palaeoenvironmental characteristics of the depositional basin on the basis of three detailed sedimentological sections logged atop the velika planina plateau. the velika planina member is underlain by a whitish to light grey, thick bedded to massive dolomite with oncoids, stromatolites, and lumachellas deposited under peritidal to shallow subtidal conditions. the lower part of the velika planina member consists of thin, often platy, finely laminated beds of bituminous mudstone. the chondrites ichnofossil is very common; however, in some beds numerous lingulid brachiopods, bivalves, and crinoids were observed. fossil vertebrates and crustaceans are relatively rare and confined to a few levels. ammonoids are very rare. subordinate beds of intraclastic-peloid wackestone to packstone, intraclastic-bioclastic grainstone, and bivalve floatstone occur. slumps are common. upwards, bedding gradually becomes thicker and bioturbation more common. finally, stromatolites, birdseye fenestrae, and oncoids reappear. the entire succession is confined to the early to middle anisian by the foraminifer citaella dinarica (kochansky-devidé & pantić). the absence of breccias at the base of the velika planina member, the gradual transition upwards into shallow marine carbonates, as well as the presence of sauropterygians of the order nothosauroidea suggest deposition in a relatively shallow basin. the finely laminated facies of the lower part of the member indicates a stratified water column, with oxygenated near-surface waters and hypoxic to anoxic conditions near the sea floor. scribed as a pachypleurosaur of the serpianosaurus – neusticosaurus clade (rieppel, 1997). more than two centuries later, new discoveries started to emerge: a placodont dentary bone from the upper ladinian or lower carnian beds of toško čelo near ljubljana (buffetaut & novak, 2008), isolated bones and teeth of sauropterygians from the carnian shallow marine deposits in the poljane valley (križnar, 2009), pachypleurosaur, placodont, and ichthyosaur bones from the anisian strelovec formation (hitij & renesto, 2010), and sauropterygian bones from the ladinian buchenstein formation in the kamnik-savinja alps and the southern karavanke mountains (hitij et al., 2010b). however, most of the new finds of sauropterygians came from the anisian beds of the velika planina member on the velika planina mountain plateau (fig. 1), where they occur together with a number of actinopterygian fish genera of the so-called “early anisian fish fauna” (hitij et al., 2010a; tintori et al., 2014a). despite the importance of these finds and the large potential for future palaeontological research, the stratigraphic position of the velika planina member remains poorly constrained, with no information on its lower and upper boundaries. moreover, the sedimentological composition of the member as a whole and its microfacies association have not been previously described. article history: manuscript received june 22, 2021 revised manuscript accepted october 19, 2021 available online january 31, 2022 keywords: southern alps, intraplatform basin, anisian, sedimentology, vertebrates, sauropterygia g eo lo gi a c ro at ic a geologia croatica 75/1102 the aim of this paper is to fill this gap by presenting several key sections of the velika planina member. we provide direct evidence for the early to middle anisian age of the member on the basis of determinations of foraminifers. based on the detailed description of microfacies associations and currently known fossils from this member, we try to provide some answers about the relative depth of the depositional area, the type of sedimentation, and the palaeoenvironmental conditions on the sea floor. 2. structural setting of the kamnik savinja alps velika planina is a karstified mountain plateau with an average altitude of 1500 m, located in the southern part of the kamniksavinja alps (fig. 1). in terms of regional tectonic structure, the kamnik-savinja alps belong to the eastern southern alps, shaped during the cretaceous to cenozoic alpine orogeny (placer, 1999; schmid et al., 2008). together with the southern karavanke mountains, they represent a mega shear lens between two major dextral strike-slip faults in the periadriatic fault zone: the periadriatic fault to the north and the sava fault to the south. while the main, northern branch of the periadriatic fault formed during the oligocene and was later reactivated several times, the main movements along the sava fault took place after the latest miocene (vrabec & fodor, 2006). the two dextral strikeslip faults are connected by left strike-slip faults running in nesw directions. palaeomagnetic directions from oligocene to neogene sediments indicate domino-like block rotations along these faults (fodor et al., 1998; vrabec & fodor, 2006; vrabec et al., 2006). prior to the formation of the shear zone, the area experienced two major phases of thrusting: the ne – sw directed eocene – oligocene thrusts preceded the n – s directed miocene – recent thrusts (placer, 1999; ponton, 2014). in the central part of the kamnik-savinja alps, mioč et al. (1983) distinguished the so-called savinja thrust overlying the southern karavanke thrust. celarc (2004) later found no evidence of a thrust in the northern part of the kamnik-savinja alps, which called into question the existence of the savinja thrust in that area. dolžan (2017) recently confirmed the existence of a detachment surface (named the kočna detachment surface, kds) in the central kamnik-savinja alps, dipping 8° to the e. however, no evidence for thrusting was found, and the kds was interpreted as a low-angle normal fault, that is towards the nw successively lowered along normal faults until it is no longer exposed. 3. triassic stratigraphy of the kamniksavinja alps systematic geological research of the kamnik-savinja alps started in the second half of the 19th century (lipold, 1856; rolle, 1857; teller, 1885, 1898 a, b). modern geological maps were produced by buser and cajhen (1977), mioč et al. (1983), premru (1983a), and celarc (2004). accompanying explanatory books were written by buser (1980), mioč (1983), and premru (1983b). stratigraphic research, focused on triassic deposits, was carried out by ramovš (1973), jurkovšek (1984), goričan & buser (1990), ramovš & jamnik (1991), celarc (2004), celarc & goričan (2007), celarc et al. (2013, 2014). the triassic succession preserved in the kamnik-savinja alps first reflects the existence of a mixed siliciclastic – carbonate ramp in the early triassic and then the gradual establishment of a flat and uniform carbonate platform, the formation of various smaller intraplatform basins with accompanying volcanism from the anisian until the late ladinian, regional drowning in the late carnian, and progradation of the platform in the norian (buser, 1989, 1996). the development took place at the western passive margin of equatorial pangea, close to the palaeotethys and from the middle triassic onwards also next to the neotethys ocean (haas et al., 1995; stampfli & borel, 2002; stampfli & kozur, 2006). in the kamnik-savinja alps the lower triassic is represented by sandstones, marly limestone, and oolitic limestone belonging to the werfen formation (fig. 2). this gradually passes into the lower anisian dolomite (or limestone), equivalent to the lower serla dolomite in the central southern alps (gianolla et al., 1998). the lower serla dolomite laterally and vertically passes into a succession of thinto medium-bedded, locally finely laminated bituminous limestone several tens of metres thick, here referred to as the velika planina member. the unit locally contains isolated bones and partial to complete vertebrate skeletons. on the velika planina plateau, the velika planina member gradually passes upwards into medium-bedded and then massive limestone and dolomite still belonging to the lower serla dolomite. on the velika planina plateau, this dolomite is in a faulted contact with the limestone and dolomite of the schlern formation. elsewhere in the kamnik-savinja alps (as well as in parts of the julian alps), where the contact is not disturbed by younger faults, the lower serla dolomite passes upwards into a unit of figure 1. geographical and structural position of the velika planina plateau. a map of slovenia with the location of the kamnik-savinja alps. the smaller rectangle shows the position of the inset in figure 1b. source: digital elevation model with 5 x 5 m raster grid, dem 5, 2006. slovenia, public information of slovenia, the surveying and mapping authority of the republic of slovenia. b the tectonic structure of central and northern slovenia. the position of the velika planina plateau is indicated by a star symbol. paf: periadriatic fault. šf: šoštanj fault. modified after vrabec & fodor (2006). g eologia c roatica gale et al.: a sedimentological description of the middle triassic vertebrate-bearing limestone from velika planina, the kamnik-savinja alps, slovenia 103 marlstone, mudstone, thinto medium-thick bedded limestone and dolomite of the middle to upper anisian (pelsonian – early illyrian) strelovec formation which is up to 60 m thick (celarc et al., 2013; miklavc et al., 2016; primožič, 2020). the strelovec formation is concordantly overlain by the upper anisian contrin formation, comprising shallow marine bedded and massive limestone, or locally dolomite (celarc et al., 2013). the contrin formation is locally dissected by palaeofaults. small half-grabens are filled with red radiolarian-bearing limestones of the illyrian loibl (ljubelj) formation, volcanic and volcaniclastic rocks, polymict breccias, and conglomerates (equivalent to the ugovizza/uggowitz breccia), marls, and hemipelagic limestones (equivalent to the buchenstein/livinallongo formation). upwards follow several hundred metres of massive limestone of the ladinian schlern formation (celarc et al., 2013). the growth of the schlern platform was interrupted during the late ladinian (longobardian). volcaniclastics, platy limestone with chert, and calcarenites of the korošica formation were locally deposited (jurkovšek, 1984; celarc, 2004; žalohar & celarc, 2010). elsewhere, the top of the schlern formation is marked by breccias, indicating a stratigraphic gap between the schlern formation and the lower carnian peritidal razor limestone. during the late carnian, approximately 25 m of hemipelagic martuljek platy limestone was deposited. in distal positions relative to the prograding dachstein platform approximately 150 m of lower norian limestone with chert follows. finally, after a narrow prograding reef margin, a thick succession of peritidal limestones of the dachstein formation deposited over the wider area (celarc et al., 2013). 4. geological map and setting of the velika planina plateau geological maps of the velika planina mountain plateau were produced by teller (1898a, b), and premru (1983a, b). reambulation of the geological map covering the research area was performed by one of the authors of the paper (b.v.) in 2014. the southern part of the velika planina plateau is dominated by middle triassic carbonates, i.e. the anisian lower serla dolomite and the velika planina member (fig. 3). to the north, these two anisian units are in faulted contact with the younger shallow marine dolomites and subordinate limestones of the ladinian schlern formation. to the south, the lower serla dolomite is in normal stratigraphic contact with the lower triassic werfen formation. the latter is thrusted over the middle triassic dolomite. lineation on the thrust plane indicates initial thrusting to the sw, overprinted by younger thrusting to the s. the area is additionally transected by steep faults of ssw-nne, ne-sw, nee-sww, and nw-se strikes, respectively. we were unable to determine whether some of these are reactivated synsedimentary faults. figure 2. stratigraphic column of the triassic in the kamnik-savinja alps. modified after žalohar & celarc (2010). figure 3. geological map of part of the velika planina plateau. a) position of the studied area. b) geological map and position of the sections. g eo lo gi a c ro at ic a geologia croatica 75/1104 5. materials and methods the velika planina member was logged and sampled in three sections on top of the velika planina plateau (figs. 3–4). in addition, samples from the lower serla dolomite below the velika planina member were collected from outcrops at the “jarški dom” hut (samples jar 1–17 on fig. 4), and an additional sample from a massive limestone overlying the velika planina member was taken at “dovja raven” (sample dr-k). altogether, 71 thin-sections 28 × 47 mm in size were made. selected thin-sections were stained with alizarin red. textures were defined according to classifications by dunham (1962), and embry & klovan (1971). in determining floatstone, we follow the criteria of wright (1992), considering matrix as mud to silt-sized grains. textures were also defined based on a comparison with examples in flügel (2010). when adding the constituents to the name of the carbonate, we follow the reverse ranking order, putting the dominant component first (e.g. packstone dominated by bioclasts and with subordinate intraclasts was named bio-intraclastic packstone), as suggested by wright (1992). the fossil material was collected from several outcrops of the velika planina member. all specimens are housed within the hitij & žalohar palaeontological collection, curated, and registered according to slovenian legislation in the slovenian museum of natural history, ljubljana, slovenia. 6. lithological composition of the studied sections lower serla dolomite the velika planina member is underlain by whitish to light grey thick bedded to massive dolomite some 100 m thick, sampled at the locality “jar” (see fig. 3). the dolomite macroscopically contains numerous oncoids, stromatolites, bivalve and gastropod lumachellas. several foraminifers, including citaella dinarica (kochansky-devidé & pantić) have been found in several microfacies types. microfacies types comprise mudstone, partly washed bioclastic wackestone, partly washed intraclastic-bioclastic wackestone to packstone, dolomitized dasycladacean grainstone, microbial intraclastic rudstone, dolomitized bivalve rudstone, microbialite boundstone, and microbialite wackestone or bafflestone (table 1; fig. 5). velika planina member – section vp1 the transition from light grey lower serla dolomite into darker, thinner, and finely laminated limestone beds of the velika planina member appears to be gradual. the basal part of the velika plani na member was logged in the 26 m long section vp1 (fig. 6). platy to thin-bedded dark bituminous and finely laminated micritic limestone predominates. slumps are common. subordinate are table 1. microfacies types of the lower serla dolomite (locality jar on fig. 3, and samples jar 1–17 on fig. 4). microfacies description figures mudstone micrite containing very rare ostracods, micritic tubular fossils and echinoderms. some dissolution voids are present. gradually passes into bioclastic wackestone. / partly washed bioclastic wackestone clasts represent approximately 30% of the area. most are probably bioclasts, replaced by drusy mosaic cement. bivalve shells can be recognised besides smaller oval bioclasts. shells are encrusted by microbialite. echinoderms, rimmed with syntaxial cement, are very rare, as well as ostracods. approximately 30% of the grains are microbialite intraclasts. the intergranular space is filled with brown dolomicrospar, locally containing small pellets (microbial in origin?). dissolution voids are filled with large elongated crystals of carbonate. 5a partly washed intraclastic-bioclastic wackestone to packstone (?) texture is heterogenous. grains occupy 20–50% of the thin section area. predominant are microbialite intraclasts (estimated 75% of the grains). bioclasts are casts of shell fragments and geniculi of dasycladacean algae, filled by sparry calcite, echinoderm plates, and foraminifers (endotebanella kocaeliensis (dager), ?earlandinita sp., ?citaella dinarica (kochansky-devidé & pantić), nodosaria ordinata trifonova, ?duostominidae). the intergranular space is filled with microsparite, which is partly washed out and/or corroded. echinoderm plates are overgrown by syntaxial cement. 5b dolomitized dasycladacean (?) grainstone rounded recrystallized grains represent 40–50% of the total thin section area. they are in point contacts and often stuck together in bundles. individual grains are 0.9–1.3 mm in diameter. the majority of them could belong to dasycladacean algae. alternatively, some smaller grains could also be interpreted as ooids. the intergranular space is filled by dolomicrosparite and anhedral to subhedral dolomite. 5c microbial intraclastic rudstone intraclasts larger than 2 mm represent up to 20% of the thin section area. most belong to microbialite (thrombolite and leiolite). large grains are supported by the grainstone in which smaller microbialite intraclasts and peloids predominate. very rare are ostracods (2.5%), foraminifers (0.5%; trochammina almtalensis koehn-zaninetti, ?endotriadella sp., citaella dinarica (kochansky-devidé & pantić), sessile foraminifers with dark micritised walls), echinoderms and bivalves (0.5%). the intergranular space is filled by anhedral to subhedral carbonate. echinoderm plates are overgrown by syntaxial cement. cockade textures are locally common. they are filled with zoned euhedral dolomite crystals. 5d–e dolomitized bivalve rudstone bivalve shells larger than 1 cm occupy 40% of the area. shells are replaced by dolomite cement. the supporting grainstone is nearly identical in composition to the intraclastic grainstone described above. citaella dinarica (kochansky-devidé & pantić), earlandinita sp. and sessile foraminifers were determined among microfossils. small gastropods are also present. fibrous to acicular rim cement precedes drusy mosaic spar. 5f microbialite boundstone the sample is interpreted as microbialite boundstone with intraclastic wackestone matrix. microbial carbonate forms irregular clusters. the intergranular space is filled by microspar, whereas some fenestrae are filled with true spar. besides the larger microbialite clumps/clasts, it contains smaller echinoderms, foraminifers (trochammina almtalensis koehn-zaninetti, earlandia sp.), and bivalve shells. 5g microbialite wackestone or bafflestone branching clasts of microbialite are surrounded by microspar. the microsparitic matrix locally contains larger irregular cavities filled with elongated calcite, followed by subhedral drusy mosaic cement. complete bivalves and calcimicrobes are rarely preserved. the microbialite embeds an unknown organism, which either had no skeleton or had a skeleton that later dissolved and was replaced by spar. the remaining shape reveals a tubular shape, a smooth inner side, and an irregular outer surface. 5h figure 4. schematic stratigraphic column with relative positions of samples and sections. g eologia c roatica gale et al.: a sedimentological description of the middle triassic vertebrate-bearing limestone from velika planina, the kamnik-savinja alps, slovenia 105 figure 5. microfacies of the lower serla dolomite. a) partly washed bioclastic wackestone. thin section 1490. b) partly washed intraclastic-bioclastic wackestone to packstone. thin section 1496. c) dolomitized dasycladacean (?) grainstone. thin section 1486. d) large microbialite intraclast within a microbial intraclastic rudstone. thin section 1495. e) intraclastic grainstone matrix of a microbial intraclastic rudstone. thin section 1497. f ) dolomitized bivalve rudstone. thin section 1493. g) microbialite boundstone. thin section 1501. h) microbialite wackestone or bafflestone. thin section 1488. g eo lo gi a c ro at ic a geologia croatica 75/1106 beds of calcarenite up to 15 cm thick, which are lighter in colour and without lamination. seven microfacies types are determined, namely mudstone, finely laminated mudstone, earlandia mudstone, peloid wackestone with ostracods, partly washed intraclastic-peloid wackestone to packstone, intraclastic-bioclastic grainstone, and bivalve floatstone (table 2; fig. 7). small-scale bioturbations are locally present. velika planina member – section vp2 section vp2 comprises dark brown to almost black micritic limestone 10.5 m thick in total. most beds are thicker than in section vp1 from the lowermost part of the member, measuring between 15 cm and 1 m in thickness. lamination is commonly present, but the laminae are also much thicker (approximately 1 cm). subordinate are platy to thin-bedded beds with finer lamination, which no figure 6. sections of the velika planina member. g eologia c roatica gale et al.: a sedimentological description of the middle triassic vertebrate-bearing limestone from velika planina, the kamnik-savinja alps, slovenia 107 table 2. microfacies types of the lower velika planina member (section vp1). *the number in brackets refers to the microfacies type number in fig. 6. microfacies description figures mudstone (*1) micritic matrix is recrystallised into microsparite. ostracods and bioturbations are very rarely present. / finely laminated mudstone (*2) the microsparite is finely laminated. laminae are mostly horizontal and parallel to each other, between 0.05 mm and 2.51 mm thick. in some samples, they are deformed as a result of slumping. the grey-coloured laminae are separated by thinner, 0.04–0.48 mm thick laminae of darker micrite or microsparite. besides laminae of mudstone, some rare sparse wackestone laminae up to 1 cm thick with very small peloids, foraminifers (?earlandia sp., nodosaria ordinata trifonova, miliolida), ostracods or thin-shelled bivalves are present. microsparite locally contains rhomboidal crystals of calcite. they are more common in the darker laminae. lamination follows the outlines of the crystals. one sample contained elliptical horizontal and vertical burrows filled with pellets and cutting through the laminae. small-scale synsedimentary faults are locally present. some samples are stylolitised concordant or oblique to the bedding planes. 7a earlandia mudstone (*4) micritic matrix is laminated. laminae are slightly wrinkled. they are wider and more uniformly dark than in mf 1. the presence of earlandia tintinniformis (mišik) is characteristic, especially in slightly darker laminae. other foraminifers (nodosaria ordinata trifonova) and ostracods are rarely present. 7b peloid wackestone with ostracods (*7) grains represent 25–40% of the area. peloids and intraclasts represent 15–20% of the area. ostracods with complete carapaces or separated valves are always present (8–15% of the area). filaments, echinoderm plates, and foraminifers (earlandia tintinniformis (mišik), nodosaria ordinata trifonova, glomospira sp., endotriada sp., trochammina sp.) are rarer. micritic matrix is locally recrystallised into microspar. 7c partly washed intraclastic-peloid wackestone to packstone (*8) grains represent 30–50% of the area. they are moderately to poorly sorted: the mean grain size is 0.15 mm, while the largest reach sizes up to 5.3 mm. peloids and micritic intraclasts strongly predominate. ostracods, echinoderms, foraminifers (endoteba sp., ?earlandia sp.), fragments of brachiopods and bivalve shells (casts filled with sparry calcite) are very rare. micritic matrix is partly washed out, and part of the intergranular space is filled with drusy mosaic calcite. echinoderm plates are overgrown by syntaxial calcite cement. note: similar microfacies was sampled in section vp3. 7d intraclastic-bioclastic grainstone (?) (*11) grains are moderately well sorted. they represent 50% of the area and are in point contacts. their mean size is approximately 0.15–0.2 mm. small micritic intraclasts and pelletoids predominate (35% of area). rare coated grains built by sessile foraminifers and microbialites are also recognisable. particles with micritised margins and filled with sparry calcite occupy approximately 7% of the area. foraminifers (3%), echinoderms (3%) and ostracods are less common. the foraminifers are glomospira sp., endotriada tyrrhenica vachard et al., endoteba bitynica vachard et al., earlandia gracilis (pantić). the cement is subhedral, probably drusy mosaic calcite. 7e bivalve floatstone (*14) the dominant bioclasts are bivalve shells. they are in point or long contacts. bivalves are mostly disarticulated, but the valves are not fragmented, up to 2 cm long. gastropods are rarely present. the intergranular space is filled with micritic matrix. 7f table 3. microfacies types of the middle velika planina member (section vp2). *the number in brackets refers to the microfacies type number in fig. 6. microfacies description mudstone (*1) see description in table 2. mudstone with filaments and sessile foraminifers (*5) disarticulated thin-shelled bivalves with attached sessile foraminifers float in micritic matrix, recrystallized into microspar. table 4. microfacies types of the upper velika planina member (section vp3). *the number in brackets refers to the microfacies type number in fig. 6. microfacies description figures bioturbated mudstone with sparse bioclasts (*6) micritic matrix predominates. elongated lenses of microspar suggest bioturbation. rare bivalves and unidentified shells are present. 8a microbial laminated mudstone (stromatolite) (*3a) micritic limestone exhibit light and dark brown sub-millimetre thick laminae. the darkest laminae have wavy or even more irregular upper surfaces and consist of dense micrite. the wider and lighter laminae are mudstone or pellet packstone. pellet grainstone is locally present, as well as fenestrae. 8b microbially-bound grainstone with fenestral fabric (stromatolite) (*3b) microbalite laminae are dense, structureless, or made of clots of dark micrite. desiccation cracks and fenestrae are locally present. microbialite binds grainstone with peloids and/or particles of dissolved and neomorphically replaced bioclasts. foraminifers (?glomospirella irregularis (moeller)) are locally present. 8c partly washed intraclasticpeloid wackestone to packstone (*8) see description in table 2. foraminifers in this part are: glomospira sp., ?palaeolituonella meridionalis (luperto), ?endotebanella sp., trochammina jaunensis brönnimann & page, ?earlandia sp., and nodosariidae. / peloid wackestone (*9) micritic matrix predominates. angular to subangular peloids represent 15% of the thin section area. subrounded to rounded sparitic grains are also present. foraminifers (glomospira sp., earlandia sp.) are very rare. / bioclastic-peloid grainstone (*10) grains occupy 65% of the total area. they are in point contacts. the prevailing grain size is around 0.15 mm (ranges between 0.03 mm and 0.7 mm). the most common grains are subrounded to rounded sparitic bioclasts (45% of the area), which may have been leached-out and replaced by spar. the rest of the grains are peloids (20% of the area), which are subangular to angular. foraminifers (“glomospira sp.”, earlandia sp.) are very rare. intergranular space is filled with drusy mosaic spar. 8d oncoid floatstone (*13) oncoids form 10–40% of the area. they are up to 1.5 cm large. cortices consist of dark micrite and sessile foraminifers. vagile foraminifers were occasionally trapped in oncoids. while most cores cannot be determined, some oncoids formed around bivalve shells and geniculi of dasycladacean algae. the space between oncoids is filled by grainstone. in thin section 1525 it is made of peloids and small oncoids. foraminifers (glomospira sp., ?glomospirella irregularis (moeller)) are also common, while gastropods and casts of small particles filled with sparry calcite are rare. in contrast the grainstone in thin section 1529b consists mostly of well-rounded particles preserved as casts filled with sparry calcite and micritic intraclasts. rare gastropods, dasycladacean algae, echinoderms, and bivalve shells are also present. foraminifers are less common than in thin section 1525, but represented by the same taxa. the cement is drusy mosaic, in thin section 1529b proceeded by acicular rim cement. some larger vugs are filled with euhedral crystals of zoned (banded) carbonate and crystal silt. echinoderm plates are overgrown by syntaxial cement. 8e peloid-bioclastic grainstone (*12) grains represent 50% of the area. they are in point contacts. except for some large (up to 2.5 mm) gastropod shells, the rest of the grains are moderately sorted. bioclasts and peloids are present in approximately equal amounts. subangular to subrounded sparitic particles with microsparitic outlines represent the majority of the former. among the recognisable bioclasts are foraminifers (glomospira or hoyenella sp.) and some bivalve fragments. cockade structures are rimmed by bladed spar and filled partly with crystal silt and partly by subhedral dolomite. subhedral dolomite also fills the intergranular space. 8f mud-supported breccia (*15) mudstone clasts are very poorly sorted and angular, floating in micrite. remarks: breccia appears in pockets within micritic limestone. / g eo lo gi a c ro at ic a geologia croatica 75/1108 longer form thicker bundles. slumping of the sediment is evident, and intraclastic rudstone (“flat-pebble breccia”) is locally present. mudstone and mudstone with filaments and sessile foraminifers (table 3) are the only microfacies types in this section. velika planina member – section vp3 the uppermost part of the velika planina member was logged in section vp3. the total length of the section is approximately 72 m, but large parts of it are poorly exposed. the bedding, however, remains constant. platy to thin-bedded dark brown mudstone predominates in the first 16 m of the section. subordinate are densely bioturbated beds of micritic limestone 70 – 100 cm thick. above, thin to medium-thick beds of light grey limestone follow. possible neptunian dykes were observed in one bed. above the 30-metre mark of the section the limestone becomes light grey in colour. wavy lamination and birdseye fenestrae are commonly present. calcarenite is present along with micritic limestone, and oncoids are present in the uppermost part of the section. microfacies types from the vp3 section are bioturbated mudstone with sparse bioclasts, microbial laminated mudstone (stromatolite), figure 7. microfacies of the velika planina member, section vp1. a) finely laminated mudstone. note rhomboidal crystals of calcite. thin section 1232b. b) earlandia mudstone. note the foraminifer earlandia tintinniformis (mišik) in the darker lamina. thin section 1232c. c) peloid wackestone with ostracods. thin section 1230. d partly washed intraclastic-peloid wackestone to packstone. thin section 1228d. e) intraclastic-bioclastic grainstone. note the foraminifer glomospira sp. in the centre. thin section 1228c. f ) bivalve floatstone. thin section 1219. g eologia c roatica gale et al.: a sedimentological description of the middle triassic vertebrate-bearing limestone from velika planina, the kamnik-savinja alps, slovenia 109 microbially-bound grainstone with fenestral fabric (stromatolite), partly washed intraclastic-peloid wackestone to packstone, peloid wackestone, bioclastic-peloid grainstone, oncoid floatstone, peloid-bioclastic grainstone, and mud-supported breccia (table 4; fig. 8). citaella dinarica (kochansky-devidé & pantić) was found approximately 20 m higher in a seemingly massive limestone (sample dr-k in fig. 4). macrofossils of the velika planina member macrofossils can be found throughout the entire velika planina member; however, they are most frequent in its lower part (section vp1). the trace fossil chondrites is relatively commonly present in the laminated bituminous limestone of the velika plani na member (fig. 9c,d). in the lower part of the member there are several beds with accumulated imprints of the bivalves of the genus modiolus. the shells are only rarely preserved. bakevellia costata (fig. 9a) is rarer, as well as some well-preserved crinoid specimens (fig. 9b). the latter belong to the genera dadocrinus and holocrinus. one complete, fully articulated crinoid specimen probably belongs to a new yet undescribed crinoid family. small ammonoids are extremely rare. the organisms with predominantly chitinous shells are generally well preserved. in some beds we find numerous lingulid inarticulate brachiopods. the inarticulate brachiopods of the genus ?discinisca are rarer and occur only as single specimens. other brachiopods are also present, but are not sufficiently preserved for a determination. crustacean fossils are very rare (fig. 9d), e.g. mass mortality beds with lobsters in their larval stage. vertebrate fossils are more common in the figure 8. microfacies of the velika planina member (upper part), section vp3. a) bioturbated mudstone with sparse bioclasts. arrowhead points at the undetermined shell. thin section 1509. b) microbial laminated mudstone (stromatolite). thin section 1511. c: microbially-bound grainstone with fenestral fabric (stromatolite). thin section 1528. d) bioclastic-peloid grainstone. thin section 1517. e: oncoid floatstone. a large oncoid, formed mostly by sessile foraminifers, floats in bioclastic-intraclastic grainstone. thin section 1525. f ) peloid-bioclastic grainstone with gastropod shells. thin section 1529a. g eo lo gi a c ro at ic a geologia croatica 75/1110 lower part of the member. some specimens are completely articulated and can even bear impressions of soft tissues. others show partial disarticulation (fig. 9f). several remains of sauropterygian reptiles of the order nothosauroidea were discovered, among them also a complete, fully articulated specimen more than 1 m long. several genera of actinopterygian fish are also present (see tintori et al., 2014a). these include at least two different species of the genus saurichthys, together with eosemionotus, placopleurus, furo (fig. 9e), at least one other neopterygian fish, probably closely related to the basal semionotiform sangiorgioichthys, and the isolated remains of a coelacanth. coprolites are quite abundant (fig. 9g). 7. discussion on characteristics and evolution of the basin triassic rocks, which today form the majority of the kamniksavinja alps, were deposited on the continental shelf offshore from the eastern equatorial pangea (haas et al., 1995; stampfli & borel, 2002; stampfli & kozur, 2006). no signs of tectonic activity during the early triassic have been reported from this region so far, and a shallow marine mixed carbonatesiliciclastic shelf developed. with the rising sea level, carbonate sedimentation prevailed, giving rise to the anisian carbonate platforms (buser, 1989, 1996). the velika planina member, underand overlain by light-coloured peritidal carbonates, testifies figure 9. fossils of the velika planina member. a) a bivalve bakevellia costata; length 7 mm. b) an undescribed crinoid; length of the crown 9 mm. c) chondrites ichnogenus; width of the photo is 4 mm. d) a mass mortality bed with arthropod remains and the trace fossil chondrites; length of the arthropod on the right is 5 mm. e) a fish of the genus furo coated by ammonium chloride sublimate; length of the fish is 5 cm. f) a sacral region of a sauropterygian reptile of the order nothosauroidea exposed on the site, length of the specimen is 9 cm. g) a coprolite; length is 5 cm. image credit: (a, b, e): jure žalohar tomaž hitij; (c, d, f): tomaž hitij. g eologia c roatica gale et al.: a sedimentological description of the middle triassic vertebrate-bearing limestone from velika planina, the kamnik-savinja alps, slovenia 111 to a relative deepening of part of the anisian platform, probably due to local tectonic subsidence. the finding of the foraminifer citaella dinarica, both in the underlying rocks and in the transitional interval to the overlying peritidal limestones, confines the deposition of the velika planina member to the early to middle anisian (rettori, 1995; ueno et al., 2018). this age estimation is consistent with the previously estimated pre-pelsonian age of the velika planina member based on the biostratigraphy of fossil fishes (tintori et al., 2014a). the diversity of bioclasts, which include echinoderms and dasycladacean algae, and the light grey colour of the underlying massive or poorly bedded lower serla dolomite suggests initial deposition in an oxygenated shallow marine environment of a carbonate platform. the platform was microbially-dominated, as evidenced by the abundance of microbialites. bivalve and gastropod lumachellas represent local accumulations of shells. the absence of breccia at the base of the velika planina member and a gradual shift from light grey intertidal dolomites to dark bituminous limestone suggest a gradual deepening and the subsequent establishment of a shallow restricted basin. due to the limited areal extent of the basin, the deepening was probably caused by subsidence along normal faults. slumping is especially common in the lower and middle part of the velika planina member (sections vp1, vp2), but was not observed in the uppermost part (section vp3). this could suggest the basin was deeper in its early evolution, or (more likely) initially a more active tectonic subsidence, with a quiescence of tectonic activity later on. the relatively shallow nature of the basin, or at least the lack of connection with an open sea, is supported by the nearabsence or even lack of open-marine plankton and nekton, such as radiolarians and ammonoids, within the velika planina member and a subsequent gradual transition into oxygenated shallow marine facies within section vp3. the lower part of the velika planina member (section vp1) is recognised by the predominance of finely laminated mudstone. the facies association here is similar to the lower ladinian meride limestone of monte san giorgio in southern switzerland/ northern italy (furrer, 1995a; stockar, 2010: “laminate lithofacies”), the upper anisian to lower ladinian posanto formation in eastern switzerland (bürgin et al., 1995; furrer, 1995b, 2019), and the cretaceous komen limestone in slovenia (palci et al., 2008). at this stage, the water column was likely stratified, with oxygenated near-surface layers and hypoxic to anoxic conditions at the bottom. this is suggested by the preservation of coprolites, as well as articulated vertebrate skeletons. mudstone, finely laminated mudstone, and earlandia mudstone all represent background sedimentation. the darker laminae are richer in organic matter and could represent microbial mats on the basin floor. the general absence of larger benthos, the bituminous nature of the limestone, and the fine lamination of the sediment suggest poorly ventilated bottom conditions. this is supported by the profuse presence of chondrites and the near exclusion of all other trace fossils (bromley & ekdale, 1984). however, the local presence of bioturbations, small and rare bivalves, rare crinoids, and even the presence of small benthic foraminifers, such as earlandia and thin-shelled lagenids, suggest an occasional presence of free oxygen in the uppermost sediment. earlandia is considered a benthic opportunist (krainer & vachard, 2009), and thin-shelled lagenids were tolerant of oxygen-poor conditions (stockar, 2010). partly washed intraclastic-peloid wackestone to packstone and intraclastic-bioclastic grainstone, on the other hand, indicate deposition in a more energetic setting. size-sorting of particles indicates transport, and at least some of the bioclasts (e.g., foraminifers glomospira sp., endothyracea, and mollusc fragments) probably originated from a better aerated shallow marine environment. we suggest deposition from diluted turbidity currents. parautochthonous or allochthonous origin is also suggested for peloid wackestone with ostracods, and bivalve floatstone. higher up in the succession (sections vp2, vp3), beds are thicker and lamination is less pronounced. more sediment was perhaps shed from the surrounding shallow carbonate platform, or perhaps the conditions on the sea floor became more stable and less restricted. in the last of the logged sections (vp3), the intraplatform basin’s deposits gradually give way to the well oxygenated shallow platform carbonates of the platform top. bioturbation is common in the lower part of the vp3 section, and from the 30-metre mark upwards there are several indicators of peritidal conditions: wavy stromatolites, fenestrae, even a foraminiferal assemblage, dominated by glomospiral forms. grainstones with various bioclasts, especially fragments of molluscs, again suggests an environment densely populated by benthic invertebrates. finally, oncoids from the top of the section indicate the presence of waves and/or currents. even though the velika planina member was initially considered to represent a deeper marine basin (hitij et al., 2010a), the evidence presented above tends to support the idea of a rather shallow intraplatform basin. this is also supported by the vertebrate remains found in the lower part of the velika planina member. among the groups of marine reptiles, only nothosauroids have been identified so far, and these were limited to shallow intraplatform basins and shallow epicontinental seas (rieppel, 1999; černansky et al., 2018). 8. conclusions the velika planina member was deposited within a relatively shallow and restricted intraplatform basin during the early to middle anisian. the basal part of the member is dominated by finely laminated mudstone deposited in a stratified basin with mainly hypoxic to anoxic bottom conditions. actinopterygian fishes and marine reptiles are well preserved in this facies due to limited bioturbation and scavenging on the sea floor. moving upwards, restricted facies gradually gives way to well-oxygenated shallow platform carbonates of the lower serla dolomite. acknowledgement this research was financially supported by the slovenian research agency (research core funding no. p1-0011 to l.g. and b.c., core funding no. p1-0195 to m.v. and j.ž., research project 1555-007-p1-0195 to j.ž.), and quantectum ag (funding to j.ž. and b.v.). we thank the technical staff of the geological survey of slovenia for the preparation of the thin sections. finally, we are very grateful to heinz furrer and an anonymous reviewer for their positive attitudes and approaches, as well as for their concrete and constructive remarks. references beardmore, s.r. & furrer, h. (2016): taphonomic analysis of saurichthys from two stratigraphic horizons in the middle triassic of monte san giorgio, switzerland.− swiss j. geosci., 109, 1–16. doi: 10.1007/s00015-015-0194-z beardmore, s.r. & furrer, h. (2019): taphonomic variation within a middle triassic fossil lagerstätte (cassina beds, meride limestone) at monte san giorgio.– palz, 93, 49–67. doi: 10.1007/s12542-018-0415-7 benton, m.j. (2016): the triassic.− current biology, 26/23, r1205–r1225. doi: 10.1016/j.cub.2016.10.060 g eo lo gi a c ro at ic a geologia croatica 75/1112 benton, m.j., zhang, q., hu, s., chen z.-q., wen, w., liu, j., huang, j., zhou, c., xie, t., tong, j. & choo, b. (2013): exceptional vertebrate biotas from the triassic of china, and the expansion of marine ecosystems after the permo-triassic mass extinction.− earth-sci. rev., 125, 199–243. doi: 10.1016/j.earscirev.2013.05.014 brayard, a., krumenacker, l.j., botting, j.p., jenks, j.f., bylund, k.g., fara, e., vennin, e., olivier, n., goudemand, n., saucède, t., charbonnier, s., romano, c., goguzhaeva, l., thuy, b., hautmann, m., stephen, d.a., thomazo, c. & escarguel, g. (2017): unexpected early triassic marine ecosystem and the rise of the modern evolutionary fauna.− sci. adv., 3, e1602159, 1–11. doi: 10.1126/sciadv.1602159 bromley, r.g. & ekdale, a.a. (1984): chondrites: a trace fossil indicator of anoxia in sediments.− science; 224, 872−874. doi: 10.1126/science.224.4651.872 buatois, l.a., carmona, n.b., curran, h.a., netto, r.g., mángano, m.g. & wetzel, a. (2016): the mesozoic marine revolution.− in: mángano, m.g. & buatois, l.a. (eds.): the trace-fossil record of major evolutionary events.− topics geobiol., 40, 19–134. doi: 10.1007/978-94-017-9597-5_2 buffetaut, e. & novak, m. (2008): a cyamodontid placodont (reptilia: sauropterygia) from the triassic of slovenia.− palaeontology, 51/6, 1301–1306. doi: 10.1111/j.1475-4983.2008.00819.x bürgin, t., eichenberger, u., furrer, h. & tschanz, k. (1991): die prosanto-formation eine fischreiche fossil-lagerstätte in der mitteltrias der silvretta-decke (kanton graubünden, schweiz).− eclogae geol. helv., 84, 921–990. doi: 10.5169/seals-166804 buser, s. (1980): osnovna geološka karta sfrj 1:100000. tolmač za list celovec (klagenfurt) l33−53 [basic geological map of sfry 1:100000, geology of the celovec (klagenfurt) sheet – in slovenian].– geološki zavod ljubljana, ljubljana, zvezni geološki zavod, beograd, 62 p. buser, s. (1989): development of the dinaric and the julian carbonate platforms and of the intermediate slovenian basin (nw yugoslavia).− boll. soc. geol. ital., 40, 313–320. buser, s. (1996): geology of western slovenia and its paleogeographic evolution.− in: drobne, k., goričan, š. & kotnik, b. (eds.): international workshop postojna ‚96: the role of impact processes and biological evolution of planet earth.– zrc sazu, ljubljana, 111–123. buser, s. & cajhen, j. (1977): osnovna geološka karta sfrj 1:100000, list celovec (klagenfurt) l33−53 [basic geological map of sfry 1:100000, celovec (klagenfurt) sheet – in slovenian].– geološki zavod ljubljana, ljubljana, zvezni geološki zavod, beograd. celarc, b. (2004): geološka zgradba severovzhodnega dela kamniško – savinjskih alp [geological structure of the northwestern part of the kamnik-savinja alps – in slovenian, with an english abstract].– unpubl. phd thesis, faculty of natural sciences and engineering, university of ljubljana, 137 p. celarc, b. & goričan, š. (2007): diferenciran razpad anizijske (ilirske) karbonatne platforme v julijskih alpah (prisojnik) in kamniško-savinjskih alpah (križevnik) [differential disintegration of anisian (ilirian) carbonate platform in the julian alps (prisojnik) and in the kamnik-savinja alps (križevnik) – in slovenian].− geološki zbornik, 18, 11–15. celarc, b., goričan, š. & kolar-jurkovšek, t. (2013): middle triassic carbonate-platform break-up and formation of small-scale half-grabens (julian and kamnik-savinja alps, slovenia).− facies, 59, 583–610. doi: 10.1007/s10347-0120326-0 celarc, b., gale, l. & kolar-jurkovšek, t. (2014): new data on the progradation of the dachstein carbonate platform (kamnik-savinja alps, slovenia).− geologija, 57/2, 95–104. doi: 10.5474/geologija.2014.009 čerňansky, a., klein, n., soták, j., olšavský, m., šurka, j. & herich, p. (2018): a middle triassic pachypleurosaur (diapsida: eosauropterygia) from a restricted carbonate ramp in the western carpathians (gutenstein formation, fatric unit): paleogeographic implications.− geol. carpathica, 69/1, 3–16. doi: 10.1515/geoca-2018-0001 deecke, w. (1886): ueber ein von herrn oberbergrath stache in der steiner alpen gesammeltes saurierfragment.− verh. k. k. geol. reichsanst., 2, 50–52. diedrich, c.g. (2012): the middle triassic marine reptile biodiversity in the germanic basin, in the centre of the pangaean world.− cent. eur. j. geosci., 4/1, 9–46. doi: 10.2478/s13533-011-0060-0 dunham, r.j. (1962): classification of carbonate rocks according to depositional texture. in: han, w.e. (ed.): classification of carbonate rocks. a symposium.− amer. ass. petrol. geol mem., 108–121. doi: doi.org/10.1306/m1357 dolžan, e. (2017): geološka zgradba in tektonika severozahodnega dela kamniških alp [structure and tectonics of the north-western part of the kamnik alps – in slovenian, with an english abstract].– unpubl. msc thesis, faculty of natural sciences and engineering, university of ljubljana, 73 p. embry, a.f. & klovan, j.e. (1971): a late devonian reef tract on northeastern banks island, n.w.t.− bull. can. petrol. geol., 19, 730–781. doi: 10.35767/gscpgbull.19.4.730 flügel, e. (2010): microfacies of carbonate rocks: analysis, interpretation and application (2nd edition). − springer-verlag, berlin heidelberg, 984 p. fodor, l., jelen, b., márton, e., skaberne, d., čar, j. & vrabec, m. (1998): miocene-pliocene tectonic evolution of the slovenian periadriatic fault: implications for alpine-carpathian extrusion models.− tectonics, 17/5, 690–709. doi: 10.1029/98tc01605 furrer, h. (1995a): the kalkschieferzone (upper meride limestone; ladinian) near meride (canton ticino, southern switzerland) and the evolution of a middle triassic intraplatform basin.− eclogae geol. helv., 88/3, 827–852. doi: 10.5169/ seals-167706 furrer, h. (1995b): the prosanto-formation, a marine middle triassic fossil-lagerstätte near davos (canton graubünden, eastern swiss alps).− eclogae geol. helv., 88/3, 681–683. doi: 10.5169/seals-167694 furrer, h. (2019): fische und saurier aus dem hochgebirge. fossilien aus der mittleren trias bei davos.– neujahrsbl. naturforsch. ges. zürich, 221, 1–112. furrer, h. & vandelli, a. (2014): guide to the museum of fossils from monte san giorgio meride.− fondazione del monte san giorgio, meride, 128 p. gianolla, p., de zanche, v. & mietto, p. (1998): triassic sequence stratigraphy in the southern alps (northern italy): definition of sequences and basin evolution.− in: de graciansky, p.c., hardenbol, j., jacquin, t. & vail, p.r. (eds.): mesozoic and cenozoc sequence stratigraphy of european basins.− sepm spec. publ., 60, 719–746. doi: 10.2110/pec.98.02.0719 goričan, š. & buser, s. (1990): middle triassic radiolarians from slovenia (yugoslavia).− geologija, 31–32 (1988/89), 133–197. haas, j., kovács, s., krystyn, l. & lein, r. (1995): significance of late permian-triassic facies zones in terrane reconstructions in the alpine-north pannonian domain.− tectonophysics, 242, 19–40. doi: 10.1016/0040-1951(94)00157-5 hagdorn, h. & rieppel, o. (1999): stratigraphy of marine reptiles in the triassic of central europe.− zbl. geol. paläont. teil i, 7−8, 651–678. hitij, t. & renesto, s. (2010): plazilci strelovške formacije [reptiles of the strelovec formation − in slovenian, with an english abstract].− in: gregori, j. (ed.): the kingdom of tethys. the fossilized world of triassic vertebrates from the kamniško-savinjske alps.− scopolia, j. slovenian mus. nat. history, suppl. 5, 68–83. hitij, t., križnar, m., žalohar, j., renesto, s. & tintori, a. (2010a): horizont velike planina – dom triasnih morskih pošasti [the velika planina horizon – home to the triassic sea monsters − in slovenian, with an english abstract].− in: gregori, j. (ed.): the kingdom of tethys. the fossilized world of triassic vertebrates from the kamniško-savinjske alps. scopolia, j. slovenian mus. nat. history, suppl. 5, 68–83. hitij, t., križnar, m. & žalohar, j. (2010b): bogastvo fosilov v ladinijskih plasteh kamniško-savinjskih alp in južnih karavank [fossils in ladinian beds of the kamniško-savinjske alps and southern karavanke mountains − in slovenian, with an english abstract].− in: gregori, j. (ed.): the kingdom of tethys. the fossilized world of triassic vertebrates from the kamniško-savinjske alps. scopolia, j. slovenian mus. nat. history, suppl. 5, 157–169. hugi, j., scheyer, t.m., sander, p.m., klein, n. & sánchez-villagra, m.r. (2011): long bone microstructure gives new insights into the life of pachypleurosaurids from the middle triassic of monte san giorgio, switzerland/italy.− c. r. palevol., 10/5–6, 413–426. doi: 10.1016/j.crpv.2011.03.009 jurkovšek, b. (1984): langobardske plasti z daonelami in pozidonijami v sloveniji [langobardian beds with daonellas and posidonias in slovenia − in slovenian, with an english abstract].− geologija, 27, 41–95. kreiner, k. & vachard, d. (2009): the lower triassic werfen formation of the karawanken mountains (southern austria) and its disaster survivor microfossils, with emphasis on postcladella n. gen. (foraminifera, miliolata, cornuspirida).− rev. micropaléont., 54/2, 59–85. doi: 10.1016/j.revmic.2008.11.001 križnar, m. (2009): karnijski vretenčarji iz poljanske doline [carnian vertebrates from the poljanska dolina valley − in slovenian].− društvene novice, 40, 21–22. lipold, m.v. (1856): geologische skizze des gebietes von sulzbach.− jahrb. d. geol. reichsanst., 7, 169–171. liu, j., rieppel, o., juang, d.-y., aitchison, j.c., motani, r., zhang, q.-y., zhou, c.-y. & sun, y.-y. (2011): a new pachypleurosaur (reptilia: sauropterygia) from the lower middle triassic of southwestern china and the phylogenetic relationships of chinese pachypleurosaurs.− j. vertebr. paleontol., 31, 292–302. doi: 10.1080/02724634.2011.550363 miklavc, p., celarc, b. & šmuc, a. (2016): anisian strelovec formation in the robanov kot, savinja alps (northern slovenia).− geologija, 59/1, 23–34. doi: 10.5474/geologija.2016.002 mioč, p. (1983): osnovna geološka karta sfrj 1:100000. tolmač za list ravne na koroškem l33−54 [basic geological map of sfry 1:100000, geology of the ravne na koroškem sheet – in slovenian].− geološki zavod ljubljana, ljubljana, zvezni geološki zavod, beograd, 69 p. mioč, p., žnidarčič, m. & jerše, z. (1983): osnovna geološka karta sfrj 1:100000, list ravne na koroškem l33−54 [basic geological map of sfry g eologia c roatica gale et al.: a sedimentological description of the middle triassic vertebrate-bearing limestone from velika planina, the kamnik-savinja alps, slovenia 113 1:100000, ravne na koroškem sheet – in slovenian].– geološki zavod ljubljana, ljubljana, zvezni geološki zavod, beograd. motani, r. (2009): the evolution of marine reptiles.− evo. edu. outreach, 2, 224–235. doi: 10.1007/s12052-009-0139-y palci, a., jurkovšek, b., kolar-jurkovšek, t. & caldwell, m.w. (2008): new palaeoenvironmental model for the komen (slovenia) cenomanian (upper cretaceous) fossil lagerstätte.− cretac. res., 29, 316–328. doi: 10.1016/j. cretres.2007.05.003 payne, j.l. & van de schootbrugge, b. (2007): life in triassic oceans: links between planktonic and benthic recovery and radiation.− in: falkowski, p. & knoll, a.h. (eds.): evolution of primary producers in the sea. academic press, amsterdam, 165–189. doi: 10.1016/b978-012370518-1/50010-2 placer, l. (1999): contribution to the macrotectonic subdivision of the border region between southern alps and external dinarides.− geologija, 41, 223–255. doi: 10.5474/geologija.1998.013 ponton, m. (2014): analisi strutturale profonda delle dinaridi esterne fra alpi e prealpi giulie (italia e slovenia) [depth stzructural analysis of the external dinaric chain in julian alps and pre-alps (italy and slovenia) − in italian, with an english extended abstract].− gortania geologia, paleontologia, paletnologia, 36, 23–34. premru, u. (1983a): osnovna geološka karta sfrj 1:100000, list ljubljana l33−66 [basic geological map of sfry 1:100000, ljubljana sheet – in slovenian].– geološki zavod ljubljana, ljubljana, zvezni geološki zavod, beograd. premru, u. (1983b): osnovna geološka karta sfrj 1:100000. tolmač za list ljubljana l33−66 [basic geological map of sfry 1:100000, geology of the ljubljana sheet – in slovenian].− geološki zavod ljubljana, ljubljana, zvezni geološki zavod, beograd, 75 p. primožič, j. (2020): biostratigrafska in sedimentološka analiza globljemorskih triasnih plasti pri preddvoru [biostratigraphic and sedimentological analysis of triassic beds at preddvor − in slovenian, with an english abstract].− unpubl. diploma thesis, faculty of natural sciences and engineering, university of ljubljana, 34 p. ramovš, a. (1973): biostratigrafske značilnosti triasa v sloveniji [biostratigraphische charakteristik der trias in slowenien − in slovenian, with a german summary].− geologija, 16, 379–388. ramovš, a. & jamnik, a. (1991): the first proof of deeper marine norian (upper triassic) beds with conodonts and holothurian skeletons in the kamnik alps (slovenia).− mining and metallurgy quarterly, 38/3, 365–367. renesto, s., binelli, g. & hagdorn, h. (2014): a new pachypleurosaur from the middle triassic besano formation of northern italy.− n. jb. geol. paläont. abh., 271/2, 151–168. doi: 10.1127/0077-7749/2014/0382 rettori, r. (1995): foraminiferi del trias inferiore e medio della tetide: revisione tassonomica, stratigrafia ed interpretazione filogenetica [lower and middle triassic foraminifers of the tethys: taxonomic revision, stratigraphy and phylogenetic interpretaton − in italian].− université de geneve, publications du départment de géologie et paléontologie, 18 (1995), 1–107. rieppel, o. (1997): part ii: sauropterygia. introduction.− in: callaway, j.m. & nicholls, e.l. (eds.): ancient marine reptiles. academic press, san diego, california, 107–119. rieppel, o. (1999): phylogeny and paleobiogeography of triassic sauropterygia: problems solved and unresolved.− palaeogeogr. palaeoclimatol. palaeoecol., 153, 1–15. doi: 10.1016/s0031-0182(99)00067-x röhl, h.-j., schmid-röhl, a., furrer, h., frimmel, a., oschmann, w. & schwark, l. (2001): microfacies, geochemistry and palaeoecology of the middle triassic grenbitumenzone from monte san giorgio (canton ticino, switzerland).− geol. insubr., 6/1, 1–13. rolle, f. (1857): geologische untersuchungen in der gegend zwischen weitenstein, windisch-gratz, cilli und oberburg in unter-steiermark.− jahrb. d. geol. reichsanst., 8/3, 403–465. schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine-carpathian-dinaric orogenic system: correlation and evolution of tectonic units.− swiss j. geosci., 101, 139–183. doi: 10.1007/s00015-008-1247-3 stampfli, g.m. & borel, g.d. (2002): a plate tectonic model for the paleozoic and mesozoic constrained by dynamic plate boundaries and restored synthetic oceanic isochrons.− earth planet. sci. lett., 196, 17–33. doi: 10.1016/s0012821x(01)00588-x stampfli, g.m. & kozur, h.w. (2006): europe from the variscan to alpine cycles.− in: gee, d.g. & stephenson, r.a. (eds.): european lithosphere dynamics.− geol. soc. mem., 32, 57–82. doi: 10.1144/gsl.mem.2006.032.01.04 stockar, r. (2010): facies, depositional environment, and palaeoecology of the middle triassic cassina beds (meride limestone, monte san giorgio, switzerland).− swiss j. geosci., 103, 101–119. doi: 10.1007/s00015-010-0008-2 stubbs, t.l. & benton, m.j. (2016): ecomorphological diversifications of mesozoic marine reptiles: the roles of ecological opportunity and extinction.− paleobiology, 42/4, 547–573. doi: doi.org/10.1017/pab.2016.15 teller, f. (1885): fossilführende horizonte in der oberen trias der sanntataler alpen.− verhandl. geol. reichsanst., 355–361. teller, f. (1898a): geologische spezialkarte der k. k. österreichisch – ungarischen monarchie 1:75 000, blatt eisenkappel und kanker, zone 20, col. 11 [geological map of österreichisch – ungarischen monarchie 1:75 000, eisenkappel and kranj sheet − in german].− k. k. geologische reichsanstalt, wien. teller, f. (1898b): geologische spezialkarte der k. k. österreichisch – ungarischen monarchie 1:75 000. erläuterungen zur blatt eisenkappel und kanker [geological map of österreichisch – ungarischen monarchie 1:75 000, geology of the eisenkappel and kranj − in german].− k. k. geologische reichsanstalt, wien, 150 p. tintori, a., hitij, t., jiang, d., lombardo, c. & sun, z. (2014a): triassic actinopterygian fishes: the recovery after the end-permian crisis.− integr. zool., 9/4, 394–411. doi: 10.1111/1749-4877.12077 tintori, a., huang, j.d., jiang, d.y., sun, z.y., motani, r. & chen, g. (2014b): a new saurichthys (actinopterygii) from the spathian (early triassic) of chaohu (anhui province, china).− riv. ital. paleont. strat., 120/2, 157–64. doi: 10.13130/2039-4942/6057 ueno, k., kamata, y., uno, k., charoentitirat, t., charusiri, p., vilaykham, k. & martini, r. (2018): the sukhothai zone (permian–triassic island-arc domain of southeast asia) in northern laos: insights from triassic carbonates and foraminifers.− gondwana res., 61, 88–99. doi: 10.1016/j. gr.2018.04.013 vrabec, m. & fodor, l. (2006): late cenozoic tectonics of slovenia: structural styles at the northeastern corner of the adriatic microplate.− in: pinter, n., grenerczy, g., weber, j., stein, s. & medek, d. (eds.): the adria microplate: gps geodesy, tectonics and hazards.− nato sci. ser., iv, earth environment. sci., 61, 151–168. doi: 10.1007/1-4020-4235-3_10 vrabec, m., pavlovčič prešeren, p. & stopar, b. (2006): gps study (1996– 2002) of active deformation along the periadriatic fault system in northeastern slovenia: tectonic model.− geol. carpathica, 57/1, 57–65. wright, v.p. (1992): a revised classification of limestones.– sed. geology, 76, 177–185. doi: 10.1016/0037-0738(92)90082-3 žalohar, j. & celarc, b. (2010): geološka zgradba kamniško-savinjskih alp [geological structure of the kamniško-savinjske alps − in slovenian, with an english abstract].− in: gregori, j. (ed.): the kingdom of tethys. the fossilized world of triassic vertebrates from the kamniško-savinjske alps.− scopolia, j. slovenian mus. nat. history, suppl. 5, 43–51. 2022 | 75/special issue | 303–315 | 9 figs. | 5 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the čukaru peki hydrothermal system is part of the bor metallogenic zone, which is hosted by the timok magmatic complex (janković, 1990; kolb et al., 2013). this complex is considered to be the eastern segment of the large magmatic and metallogenic arc known as the apuseni-balkan-timok-srednogorje belt (abts belt, which is located in romania, serbia and bulgaria (neubauer, 2002). the abts belt is characterized by the presence of numerous porphyry and polymetallic ore deposits (moldova noua, bor, elatsite, chelopech), which were formed during the subduction processes associated with the closure of the neothetys ocean, between 92 and 75 ma (neubauer, 2002; fügenschuh & schmid, 2005; gallhofer et al., 2015). the magmatic activity in the timok magmatic complex was manifested in two or three volcanic phases (drovenik, 1961; janković, 1990), which altogether lasted around 10 ma (von quadt et al., 2002). it is generally accepted that most of the significant ore deposits in this complex were formed during the first volcanic phase (janković, 1990; kolb et al.,2013; jelenković et al., 2016), which lasted from 89 to 84 ма (von trace elements in pyrite from the čukaru peki porphyry cu-high-sulfidation deposit, serbia: implications for ore evolution in a polyphase hydrothermal system miloš velojić1, viktor bertrandsson erlandsson2, frank melcher2, peter onuk2,3, rade jelenković1 and vladica cvetković1 1 faculty of mining and geology, djušina 5, belgrade, serbia; (milos.velojic@rgf.bg.ac.rs) 2 montanuniversität leoben, department applied geosciences and geophysics, peter-tunner-straße 5, leoben, austria 3 karl-franzens university graz, institute of earth sciences, austria doi: 10.4154/gc.2022.25 abstract čukaru peki is a recently discovered porphyryhigh-sulfidation cu-au deposit located 5km south of the mining town of bor in east serbia. three styles of mineralization are distinguished in the čukaru peki system: a high-sulfidation type with massive sulfides (named the upper zone), a porphyry type (named the lower zone) and a transition type (between porphyries and massive sulfides). this study investigates the concentration and distribution of trace elements in pyrite from these three mineralization zones of čukaru peki. the high-sulfidation pyrite contains elevated concentrations of v, mn, ni, cu, as, mo, ag, cd, in, sn, sb, au, hg, tl, pb and bi, compared to pyrite from the porphyry zone. the porphyry zone pyrite contains elevated concentrations of co and se. the sample from the transition zone contains concentrations between the two other zones, with the exception of the relative enrichment of co and ag. this research also aims to separate different stages of ore deposition. the porphyry stage contains several types of veins: quartz a veins, quartz b veins, pyrite d veins, magnetite veins, purple anhydrite veins, sulfide veins and orange anhydrite veins. the high sulfidation stage also formed in several stages: pyrite1, pyrite-enargite veins, pyrite-covellite veins, pyrite2 veins and calcite-anhydrite veins. there are distinct differences between various vein generations found within each zone, notable examples are the enrichment of se in quartz b veins pyrite and cu in sulfide veins, compared to other veins from porphyry zone veins and the enrichment of several trace elements (cu, mo, ag, cd, in, sn, sb, au, hg, tl, pb and bi) in pyrite from the py-cov veins in comparison to the other high-sulfidation veins. the trace element data also indicates a change in fluid compositions; the earlier fluids responsible for the porphyry zone mineralization showing a slightly more magmatic fluid signature (higher co/sb and se/as values) and the later high-sulfidation fluids bearing a more typical epithermal trace element signature, which indicates cooling and diluting of fluids. some of the porphyry zone pyrite crystals (from b-type veins and purple anhydrite-veins) contain elevated concentrations of elements attributed to the high-sulfidation zone (e.g. cu, ag, cd, in, sn, pb and bi), which suggests that these veins were affected by later high-sulfidation fluids. quadt et al., 2002). the simplified map of the timok magmatic complex is shown in fig.1. the bor metallogenic zone hosts several large porphyry deposits, which have been mined since the beginning of the 20th century (bor, majdanpek, veliki krivelj) as well as other genetic types of ore deposits, such as high-sulfidation epithermal (tilva mika, kamenjar), low-sulfidation epithermal (zlaće), hydrothermal-volcanogenic (lipa, kraku bugaresku), skarns (valja saka) and recently discovered carlin-type deposits (korkan,kraku pešter and bigar hill) (janković et al., 2002; jelenković et al., 2016). estimated mineral resources of the entire zone are over 20 mt of cu and in excess of 1000 tonnes of au (jelenković et al., 2016). the čukaru peki hydrothermal system was located in 2011 and is one of the largest recently discovered cu-au deposits in south-eastern europe. preliminary estimations suggest that the total mineral resources of copper ore in this deposit could amount to between 500 and 1000 million tonnes grading more than 0,7 % cu (jelenković et al.2016). it is located just 5km south of the mining town of bor. banješević & large (2014) have article history: manuscript received october 25, 2021 revised manuscript accepted may 19, 2022 available online october 17, 2022 keywords: porphyry copper, high-sulfidation cu-as-au, pyrite, trace elements, la-icp-ms, timok magmatic complex, bor metallogenic zone g eo lo gi a c ro at ic a geologia croatica 75/special issue304 genetically classified the čukaru peki system as a porphyry cuau deposit with high-sulfidation epithermal (cu-as-au) massive sulfides. several authors have measured the concentrations and distribution of trace elements in the porphyry deposits in the bor metallogenic zones and the results of these measurements were published in several reports and doctoral dissertations (pavićević et al. (1981, 1985), mišković (1989) and vakanjac (2000)). janković et al. (2002) provide a synthesis of the obtained results of these studies and drew the following conclusions: • concentrations of au are increased (up to 49 ppm) in several studied ore minerals, e.g. in chalcopyrite, pyrite and bornite. • above detection limit concentrations of ag are present in almost all of the analyzed minerals. • enargite contains increased concentrations of ge (up to 0,46%). • palladium concentrations are increased (up to 0,5%) in different ore minerals: pyrite, chalcopyrite, bornite, digenite, covellite, luzonite and tetrahedrite, probably in the form of mineral inclusions. • selenium concentrations are increased (up to 0,5%) in bornite and covellite. • in most sulfide minerals, there is a notable enrichment (from 0,2 to 0,6%) of trace elements, such as sn, te, w, se etc. in this study we report and discuss new results from la-icpms analyses of trace elements (s, v, cr, mn, fe, co, ni, cu, as, se, mo, ag, cd, in, sn, sb, au, hg, tl, pb and bi) in pyrite grains from different zones and veins of the čukaru peki deposit, with a special emphasis on the distribution of trace elements in pyrite from different mineralization zones and ore veins. this research will contribute to a better identification of the veins and minerals in čukaru peki that concentrate rare and precious elements, such as gold and silver. the identification will be particularly significant for the extraction of gold from the high-sulfidation zone. 2. geological setting the hydrothermal system of čukaru peki is hosted by intermediate volcanic and plutonic rocks formed during the first volcanic phase of the timok magmatic complex (jelenković et al., 2016 and references therein). the volcanic rocks are represented by two distinct types of andesites: altered plagioclase-hornblende phyric, holocrystalline andesites (also called lower andesites) and unaltered hornblende-plagioclase phyric, hypocrystalline andesites (known as upper andesites) (jakubec et al., 2018). the volcanics are overlain by upper cretaceous sediments, which consist of three sedimentological units: 1) the oštrelj formation with grey siltstone and marl (uppermost) 2) the metovnica formation with red marl and epiclastics and 3) the lowermost coarsegrained bor clastites (banješević et al., 2019) (fig. 2). post-cretaceous deformation created a series of eastwarddipping faults and caused the formation of basins which were filled with miocene sediments. the most prominent structure in this region is the bor fault that splits into 2 structures, called the bor 1 and bor 2 faults, which are considered to be the eastern boundaries of the mineralized zone at čukaru peki. these structures also cut through the miocene sedimentary fill (jakubec et al., 2018). the process of basin formation was important for the preservation of cretaceous ore deposits in the timok magmatic complex from subsequent erosion (knaak et al., 2016). the miocene sediments in this area have a thickness of 200-400 m and have a discordant boundary with the cretaceous sediments (fig. 3) (jakubec et al., 2018). figure 1. a simplified geological map of the timok magmatic complex, adapted from pačevski et al. (2016) and jelenković et al. (2016). figure 2. a simplified geological map of the area around the čukaru peki ore deposit, with the location of major faults, sections and sampled drillholes. g eologia c roatica velojić et al.: trace elements in pyrite from the čukaru peki porphyry cu-high-sulfidation deposit, serbia: implications for ore evolution in a polyphase ... 305 jelenković et al. (2016) have distinguished three zones of mineralization in the čukaru peki hydrothermal system: 1) a high-sulfidation zone consists of massive sulfides, pyrite-covellite veins and hydrothermal breccias. this type of mineralization forms a localized zone, with a horizontal area of 300x300m and a vertical extent of 500 600 m and it is located at depths between 400 and 1000m from the surface., which contains the highest grades of cu (5-19%) and au (3-12g/t) (jakubec et al., 2018). with increasing depth, the mineralization contains less pyrite and becomes more characterized by veins and stockworks. the dominant type of alteration is advanced argillic alteration, with abundant residual vuggy silica, alunite and subordinate dickite (jakubec et al., 2018). the boundary of this zone is represented by a clay-rich argillic alteration (kaolinite+pyrite) halo around massive sulfides. the main cu-bearing minerals in the highsulfidation zone (upper zone) are covellite and enargite, whereas the dominant cu-bearing mineral in the porphyry zone (lower zone) is chalcopyrite, with subordinate bornite. preliminary ore microscopic examinations imply that au is present in two forms in the high-sulfidation zone of čukaru peki: 1) as tellurides such as calaverite (aute2), sylvanite (au,ag)2te4 and kostovite (aucute4); and 2) sub-microscopic native au, hosted in pyrite or sometimes bornite (jakubec et al., 2018). 2) the transition epithermal zone is located between the high-sulfidation zone and the porphyry zone. it is characterized by the replacement of early sulfides (chalcopyrite) with highsulfidation minerals (covellite and enargite). 2) anhydrite, calcite and gypsum are the three main types of vein in this zone. the main type of alteration is argillic alteration (smectite+ montmorillonite) (jakubec et al., 2018), which sporadically overprints the porphyry-type alterations. 3) the porphyry zone is mostly hosted by diorites and overlying andesites. the dimensions and shape of the porphyry zone have not yet been determined, due to its great depth; it is located at between 750m to more than 2200m from the surface. the dominant types of alteration are potassic alteration and chloritization. quartz veins (with chalcopyrite, pyrite and bornite), magnetite veins (with magnetite, hematite and chalcopyrite) and anhydrite veins (with pyrite and subordinate chalcopyrite and bornite) are the main types of veins (velojić et al., 2020). 3. samples and methods reflected light microscopy and sem measurements were performed on samples from the upper, transition and lower zones of čukaru peki. analyses were performed at montanuniversität leoben, austria and university of belgradefaculty of mining and geology, serbia. 3.1. laser ablation inductively coupled plasma mass spectrometry (la-icp-ms) trace element analyses were conducted on 5 samples from the upper zone (cp012, cp018, cp028, cp038a, and cp073), one from figure 3. simplified cross-sections through the čukaru peki ore deposit, modeled using leapfrog software, showing zones with different types of mineralization. legend: 1lower andesites; 2diorite porphyries; 3brecciated zone; 4-upper andesites; 5upper cretaceous marl; 6cretaceous epiclastics; 7upper cretaceous clastics (bor conglomerates); 8cenozoic sediments; 9massive sulfides with more than 0,5% cu; 10massive sulfides with more than 1% cu; 11massive sulfides with more than 2% cu. g eo lo gi a c ro at ic a geologia croatica 75/special issue306 the transition zone (cp126) and 5 samples from the lower zone of čukaru peki (cp084, cp115, cp117, cp119 and cp122). a description and location of all samples is shown in table 1 and the locations of drillholes are shown on figs 2 and 3. pyrite analyses were carried out using a nd:yag laser ablation system coupled to an agilent 8800 icp-ms at the department of applied geosciences and geophysics, montanuniversität leoben in austria. pyrite crystals were ablated with a spot size of 50 μm and an on-mineral laser fluency of 2-3 j/cm2, at a 10 hz repetition rate. helium was used as the carrier gas with a flow rate of 0.75 l/min, which was mixed with ar during transport to the icp-ms. isotopes measured were: 34s, 51v, 52cr, 55mn, 57fe, 59co, 60ni, 63cu, 75as, 82se, 95mo, 107ag, 111cd, 115in, 118sn, 121sb, 197au, 201hg, 205tl, 208pb and 209bi. the spot analysis procedure includes a 30 sec pre-ablation background collection, followed by 60 sec of laser ablation and data acquisition. individual ablation cycles were followed by a 30 sec washout delay. quantification of the element concentrations of pyrite were calculated using 34s as the internal standard. data reduction was performed with the iolite 4 software (paton et al., 2011). the in-house sphalerite matrix-matched sinter pressed powder pellet reference material mul-zns1 (onuk et al., 2017) was used as the primary external standard. the mass-1 usgs powder pressed polysulfide certified reference material (wilson et al., 2002) was used as the external standard for the quantification of au, tl and hg, as the reference material mul-zns-1 is not suitable for quantification of these elements. the mass-1 was also used for quality control of the analyses. both reference materials were analyzed every 20 spots for the correction of instrumental drift. detection limits were calculated by the ‘howell et al. 2010’ method option within the iolite 4 software (table 2). laser ablation spots were set out carefully to avoid inclusions, cracks or other visible impurities that could interfere with the measured data. due to pyrite crystals most commonly being zoned, it was challenging to acquire time-count signals for a single zone. thus, it is also difficult to discriminate exotic inclusions from chemical zoning in pyrite as several elements in a cu-au system could be attributed to pyrite zoning or separate phases. this may result in a wider range of trace element concentrations in a mineral population, as data was included rather than deleted when uncertain of zoning vs. inclusion. due to the generally low concentrations of many trace elements in čukaru peki (many being below detection limits), values that are below the detection limits are replaced with half the respective detection limit in the production of plots and diagrams in this study. this is a commonly used approach for handling such data. 4. results 4.1. petrography macroscopic observations of veins and their crosscutting relationhips, as well as reflected light microscopy of polished sections imply that the chronological order of deposition of mineralizing stages in the high-sulfidation (upper) zone of čukaru peki is as follows: 1) fine-grained pyrite (py1) 2) pyrite-enargite (py-en) veins 3) pyrite-covellite (py-cov) veins 4) py2 veins and 5) marcasite veins. a paragenetic sequence of the main ore stages is shown in table 3 and the main characteristics of individual stages are discussed below: 1) fine-grained pyrite (py1): replacement of rocks by very fine-grained pyrite is omnipresent in the upper zone of čukaru peki. it was probably preceded by advanced argillic alteration of rocks (with quartz and alunite) (figs.4a and 4c). this pyrite also contains subordinate rutile, but no other sulfide minerals (fig. 5a). this pyrite phase is also present within the transition zone. 2) pyrite-enargite (py-en) veins: this type of vein is common in the deeper parts of the upper zone (figs.4a and 4b). they contain intergrown grains of enargite and pyrite, with subordinate luzonite (fig.5b). the main gangue mineral in these veins is cryptocrystalline quartz (similar to chalcedony). it is commonly observed that these veins are crosscut by subsequent thin veins with pyrite and covellite (fig.4b). 3) pyrite-covellite (py-cov) veins: this is the most common type of vein in the shallow parts of the upper zone (fig.4b and 4c). the veins mostly contain covellite, pyrite and enargite, but sometimes also occur as monomineralic covellite veins (fig.5b and 5c). pyrite in these veins often exhibits colloform textures. zonation can occasionally be recognized in these veins, with colloform pyrite and enargite filling the outer parts of veins and covellite with gypsum filling the middle part. 4) pyrite2 (py2) veins: this is a rare type of thin grey veinlets that crosscut py-cov veins. they are quartz veins which contain very small euhedral pyrite grains. (fig.5d). 5) marcasite veins: these veins contain large grains of colloform marcasite, with subordinate arsenopyrite and small grains of colloform sphalerite (fig.5e). the transitional epithermal zone contains the same types of veins like the paragenetically later parts of the porphyry zone (purple anhydrite veins, sulfide veins and orange anhydrite veins), as well as py1 pyrite, which is also found in the high-sultable 1. location and description of samples used for the measurements of trace elements by la-icp-ms. abbreviations: py-pyrite; cov-covellite; en-enargite; susulfide. sample id drillhole ore zone vein description cp012 tc150096 high-sulfidation pyrite-covellite (py-cov) vein with clasts of py1 pyrite. cp018 tc150096 high-sulfidation pyrite-enargite (py-en) vein. cp028 tc150061 high-sulfidation pyrite-covellite (py-cov) vein. cp038a tc160117 high-sulfidation pyrite-covellite (py-cov) vein. cp073 tc150043 high-sulfidation pyrite-enargite (py-en) vein. cp084 fmtc1327 porphyry quartz b vein. cp115 fmtc1328 porphyry sulfide vein (su type). cp117 fmtc1328 porphyry sulfide vein (su type). cp119 fmtc1328 porphyry purple anhydrite vein. cp122 fmtc1328 porphyry pyrite vein (type d). cp126 tc160125 transition py1 pyrite. table 2. calculated median detection limits of each element measured by la-icp-ms. detection limits (μg/g). v 0.034 cd 0.98 cr 0.34 in 0.018 mn 0.18 sn 0.15 co 0.056 sb 0.054 ni 0.20 au 8e-07 cu 1.2 hg 0.28 as 2.6 tl 0.0037 se 4.1 pb 0.024 mo 0.047 bi 0.0053 ag 0.0081 g eologia c roatica velojić et al.: trace elements in pyrite from the čukaru peki porphyry cu-high-sulfidation deposit, serbia: implications for ore evolution in a polyphase ... 307 fidation zone. the main ore minerals in this zone are covellite, chalcopyrite, digenite and enargite with occasional native sulfur. the dominant type of alteration is argillic alteration (with quartz, clay minerals and sericite). in the porphyry (lower) zone of čukaru peki, several types of veins can be distinguished. most of these veins fit into the general model of veins in porphyry systems (e.g. sillitoe, 2010), so the names from the general model are used for the description of these veins. the sequence of main ore veins is shown in table 4 and the main characteristics of veins are shown below (velojić et al 2020): 1) quartz veins (type а): wiggly high temperature quartz veins that do not contain ore minerals. 2) quartz veins (type b): mostly occur as stockwork veins which contain chalcopyrite, with subordinate pyrite and bornite (fig.4d, fig. 5f). they are usually accompanied by phyllic alteration (with potassic feldspar and secondary biotite, with subordinate magnetite and anhydrite). small grains of native gold and electrum were also detected in these veins by sem examination (fig. 6b and 6d). таble 3. paragenetic sequence of mineralization in the high-sulfidation (upper) zone of čukaru peki. py1 pyrite py-en veins py-cov veins py2 veins marcasite veins pyrite quartz enargite covellite gypsum luzonite colusite rutile marcasite arsenopyrite sphalerite abbreviations: pypyrite; covcovellite; enenargite figure 4. crosscutting relationhips of different veins in the čukaru peki system. a) py-en vein in andesite altered by advanced argillic alteration (with grains of alunite) and py1 pyrite, tc150096 564m; b) py-cov vein crosscutting py-en vein, tc150062 592m; c) py-cov vein crosscutting py1 pyrite, tc150096 564m; d) sulfide vein crosscutting a quartz b vein, ftmc1328 1348,5m; e) d vein, crosscut by a thin orange anhydrite vein fmtc1328 1581.5m; f) thin sulfide vein crosscutting a purple anhydrite vein fmtc1327 1589.2m figure 5. reflected light photomicrographs of samples of different types of ore veins in čukaru peki. a) py1 pyrite with small grains of rutile, tc150096 476.8 m; b) thin covellite vein crosscutting a wide py-en vein with enargite and pyrite, tc150043 591.4 m; c) py-cov vein with covellite and colloform pyrite, tc160117 535 m; d) py2 vein with small pyrite grains crosscutting a covellite vein, tc150096 448m; e) colloform marcasite vein with small grains of round colloform sphalerite, tc150061 505.5 m; f) quartz b vein with chalcopyrite, bornite and pyrite, fmtc1327 1246.5 m; g) pyrite vein type; d, fmtc1328 1581.5 m; h) magnetite vein with magnetite, partially replaced by hematite and small chalcopyrite grains, tc160125, 1644m; i) anhydrite vein with a large pyrite grain with inclusions of covellite, fmtc1328 1442 m; j) sulfide vein with covellite and pyrite, fmtc1328 1312.8 m. g eo lo gi a c ro at ic a geologia croatica 75/special issue308 3) pyrite veins (type d): these veins contain relatively large and connected pyrite grains, which contain small inclusions of chalcopyrite, bornite and rutile (fig. 5g). these veins are usually accompanied by chlorite alteration (with chlorite, haematite and sericite) (fig.4e). 4) magnetite veins (type м): common veins in the deeper parts of the porphyry zone. they contain magnetite and hematite, with subordinate pyrite and chalcopyrite (fig.5h). magnetite is commonly replaced by hematite in a martitization process. 5) purple anhydrite veins: these veins have a distinct purplepink colour and are usually several centimetres wide. the most abundant mineral is pyrite, with smaller grains of chalcopyrite, covellite, chalcocite and bornite (fig. 5i, fig. 6c). they are common in both the porphyry and transition epithermal zones. 6) sulfide (su) veins : these veins are characterized by the presence of pyrite and covellite, with accompanying anhydrite (fig. 5j). like the previous type, these veins are also common in the transition epithermal zone. it is commonly observed that these veins crosscut earlier quartz and anhydrite veins (fig.4d and 4f). 7) orange anhydrite veins: they can be distinguished from purple anhydrite veins by colour, the shape of the anhydrite crystals and the absence of any ore minerals. these veins are clearly late, since they crosscut all the aforementioned veins (fig.4e). 4.2. pyrite trace element variations between the ore zones and intra-zonal variations median values of measurements on pyrite from the three ore zones (high-sulfidation, transition zone and porphyry zone) indicate a general trend of trace elements being enriched in the highsulfidation zone, compared to the porphyry zone. high-sulfidation zone pyrite is enriched in v, mn, ni, cu, as, mo, ag, cd, in, sn, sb, au, hg, tl, pb and bi, relative to porphyry zone pyrite (as seen in table 5.) one sample of pyrite from the transition zone was analyzed and it contains concentrations that fall in-between the two other zones, most commonly showing values similar to the porphyry zone. cobalt, as and ag are the only outliers of this trend. cobalt is significantly enriched in the sample from the transition zone (median 64 μg/g) compared to pyrite from both other zones (porphyry with 16 & high-sulfidation with 1.7 median μg/g). arsenic is depleted in transition zone pyrite (median 2.3 μg/g), whereas porphyry zone pyrite has slightly higher concentrations with a median value of 16 μg/g. silver shows similar concentrations in both the ag-rich sample from the transition zone and high-sulfidation zone (median 10 μg/g). nickel is also rather anomalous as it shows values more similar to the high-sulfidation zone pyrite, although the median concentrations are just between 2.3 and 6.7 μg/g. porphyry zone pyrite is significantly enriched in co (median 16 μg/g) and se (median 39 μg/g). except for three spot measurements, porphyry zone pyrite shows concentrations of both in and sn as being below the detection limit. although there are characteristic trace element trends between the zones, it is important to note that these trends are not always true for each vein type within each ore zone (fig.7). for example, se that is generally enriched in the porphyry zone, shows significantly lower concentrations in pyrite from the anhydrite veins of the porphyry zone. all measurements of porphyry zone pyrite show values below the detection limits for in and sn, except for three spots from the b-type veins. these three spots also show elevated concentrations of other elements characteristic of the high-sulfidation zone, i.e. mn, cu, ag, cd, pb and bi. this is also the case for cd in anhydrite-veins, where only two spot measurements show elevated cd contents. due to these elevated contents of elements typically found in high-sulfidation veins, b-type pyrite crystals show a wide spread in concentrations for the analyzed elements. d-type pyrite shows significantly lower median concentrations for several metals (cu, ag, au and bi), compared to the other porphyry pyrite crystals. all these elements are typically low in pyrite from the porphyry zone. anhydrite-vein pyrite shows trace element concentrations typical for the general porphyry table 4. paragenetic sequence of veins in the porphyry (lower) zone of čukaru peki (modified after velojić et al., 2020). quartz b veins pyrite d veins magnetite veins purple anhydrite veins sulfide veins pyrite chalcopyrite bornite magnetite hematite pyrrhotite rutile covellite enargite figure 6. bse image s taken during sem analysis of samples from čukaru peki. a) clausthalite (lead selenide) grain in a quartz vein type b, fmtc1327 1246.5 m; b) grain of electrum in a quartz vein type b, fmtc1327 1246.5 m; c) grain of pyrite from a purple anhydrite vein containing inclusions of chalcopyrite, chalcocite (spot 1) and bornite (spot 2), fmtc1328, 1442m; d) chalcopyrite grain containing a small inclusion of native au fmtc1327 1246.5 m. chalcopyrite grain containing a small inclusion of native au fmtc1327 1246.5 m. g eologia c roatica velojić et al.: trace elements in pyrite from the čukaru peki porphyry cu-high-sulfidation deposit, serbia: implications for ore evolution in a polyphase ... 309 table 5. statistical summary for la-icp-ms pyrite data from the three different čukaru peki ore zones. all values are in μg/g. n: total number of measurements; n: number of measurements below detection limit out of n. n may vary within a pyrite population between elements due to obvious inclusions, which have been removed from the dataset. when there are more measurements below the detection limits than above (n > n), median values are indicated by “<detection limit value”. when n > n, n is replaced with ½ the median detection limit value of the element, for median calculations. dl: median detection limit value of all measurements for each element. porphyry zone quartz veins (type b) pyrite veins (type d) n n median min max n n median min max v 6 4 <0.034 <0.034 0.24 15 15 <0.034 <0.034 <0.034 cr 6 6 <0.34 <0.34 <0.34 15 15 <0.34 <0.34 <0.34 mn 5 0 11 11 19 15 0 11 10 11 co 6 0 13 0.10 961 15 0 35 0.33 232 ni 6 2 2.3 <0.2 198 15 1 3.1 0.43 11 cu 6 1 813 <1.2 6098 15 0 8.2 1.1 81 as 6 4 <2.6 <2.6 27 15 15 <2.6 <2.6 <2.6 se 6 0 717 437 1041 15 0 64 28 113 mo 6 6 <0.047 <0.047 <0.047 15 15 <0.047 <0.047 <0.047 ag 6 1 0.81 <0.0081 1.1 15 10 <0.0081 <0.0081 0.023 cd 6 3 0.70 <0.98 3.2 15 15 <0.98 <0.98 <0.98 in 6 3 0.35 <0.018 2.3 15 15 <0.018 <0.018 <0.018 sn 5 2 1.00 <0.15 24 15 15 <0.15 <0.15 <0.15 sb 6 6 <0.054 <0.054 <0.054 15 15 <0.054 <0.054 <0.054 au 6 1 0.016 <8e-07 0.46 15 12 <8e-07 <8e-07 0.0011 hg 6 6 <0.28 <0.28 <0.28 15 14 <0.28 <0.28 0.34 tl 6 3 0.0046 <0.0037 0.022 15 13 <0.0037 <0.0037 0.021 pb 6 1 96 <0.024 278 15 15 <0.024 <0.024 <0.024 bi 5 1 0.26 <0.0053 8.8 15 15 <0.0053 <0.0053 <0.0053 porphyry zone purple anhydrite vein sulfide (su) vein n n median min max n n median min max v 15 15 <0.034 <0.034 <0.034 25 20 <0.034 <0.034 0.087 cr 15 14 <0.34 <0.34 0.98 29 23 <0.34 <0.34 3.6 mn 12 0 11 10 18 29 0 12 11 16 co 15 1 104 <0.056 158 23 0 3.6 0.072 65 ni 15 3 2.0 <0.2 7.3 24 3 0.45 <0.2 6.6 cu 10 0 43 2.9 132 21 0 1561 17 4163 as 15 15 <2.6 <2.6 <2.6 28 28 <2.6 <2.6 <2.6 se 13 0 40 27 108 25 16 <4.1 <4.1 79 mo 15 15 <0.047 <0.047 <0.047 26 26 <0.047 <0.047 <0.047 ag 15 7 0.0041 <0.0081 0.14 29 6 0.12 <0.0081 2.9 cd 15 13 <0.98 <0.98 1.6 29 29 <0.98 <0.98 <0.98 in 15 15 <0.018 <0.018 <0.018 27 27 <0.018 <0.018 <0.018 sn 15 15 <0.15 <0.15 <0.15 27 27 <0.15 <0.15 <0.15 sb 15 15 <0.054 <0.054 <0.054 28 24 <0.054 <0.054 0.16 au 15 0 0.0031 e2.3-05 0.029 29 8 0.082 <8e-07 1.0 hg 15 15 <0.28 <0.28 <0.28 29 8 0.33 <0.28 0.93 tl 15 11 <0.0037 <0.0037 0.029 29 15 <0.0037 <0.0037 0.11 pb 12 7 <0.024 <0.024 1.4 26 7 0.25 <0.024 14 bi 12 7 <0.0053 <0.0053 0.39 29 5 0.048 <0.0053 2.3 g eo lo gi a c ro at ic a geologia croatica 75/special issue310 together with d-type pyrite, the anhydrite-vein pyrite has the lowest median cu concentrations among the porphyry zone pyrite crystals (8.2 and 43 μg/g respectively). median co concenzone trends. two out of the fifteen analyzed spots show elevated cd values, as mentioned previously, which is a major deviation from the porphyry zone trend. transition high-sulfidation fine-grained pyrite (py1) fine-grained pyrite (py1) n n median min max n n median min max v 6 1 0.13 <0.034 0.33 5 0 4.9 1.1 5.7 cr 8 2 0.57 <0.34 1.3 8 1 1.5 0.17 3.3 mn 8 0 9.6 8.9 11 7 0 59 16 81 co 8 0 64 24 88 9 0 66 11 91 ni 8 0 5.0 2.8 11 9 0 15 7.9 17 cu 8 0 6442 4324 7787 9 0 9654 7881 16211 as 7 0 2.3 1.9 3.0 9 0 88 26 218 se 8 0 20 8.7 123 9 1 14 <4.1 17 mo 8 8 <0.047 <0.047 <0.047 8 0 0.42 0.15 1.1 ag 8 0 10 7.4 21 9 0 5.7 2.5 11 cd 8 8 <0.98 <0.98 <0.98 9 9 <0.98 <0.98 <0.98 in 8 8 <0.018 <0.018 <0.018 9 1 0.11 <0.018 0.37 sn 8 1 0.35 <0.15 0.71 9 0 2.8 1.4 8.6 sb 8 0 0.21 0.11 0.38 9 0 1.7 0.75 3.3 au 8 0 0.85 0.64 2.4 9 0 4.0 2.0 20 hg 8 0 0.52 0.26 0.89 9 3 0.57 <0.28 1.3 tl 8 0 0.81 0.45 2.9 9 0 24 0.60 140 pb 8 0 25 10 81 9 0 92 44 797 bi 8 0 0.97 0.54 1.5 9 0 9.5 1.7 45 high-sulfidation pyrite-enargite (py-en) veins pyrite-covellite (py-cov) veins n n median min max n n median min max v 14 0 0.17 0.030 3.3 18 0 6.3 0.68 43 cr 20 14 <0.34 <0.34 1.7 28 4 1.5 <0.34 22 mn 18 0 11 8.8 125 26 0 23 9.6 606 co 20 2 5.3 <0.056 101 29 2 0.19 <0.056 12 ni 20 1 2.3 <0.2 25 28 0 6.4 0.77 30 cu 18 0 11066 151 32781 27 0 16545 10453 35235 as 17 10 <2.6 <2.6 23 27 0 66 24 222 se 20 1 12 <4.1 47 26 2 7.7 <4.1 69 mo 19 12 <0.047 <0.047 1.1 24 0 1.3 0.13 33 ag 20 0 1.2 0.061 14 29 0 34 7.1 186 cd 20 20 <0.98 <0.98 <0.98 29 9 5.9 <0.98 31 in 20 16 <0.018 <0.018 0.14 27 0 2.0 0.18 12 sn 20 12 <0.15 <0.15 6.6 29 0 11 0.68 33 sb 20 4 0.20 <0.054 1.6 29 0 5.9 1.0 18 au 20 0 0.60 0.021 14 29 0 20 2.7 55 hg 20 13 <0.28 <0.28 1.5 29 2 6.3 <0.28 28 tl 20 2 0.018 <0.0037 16 29 0 56 6.9 657 pb 16 0 1.5 0.30 254 28 0 1224 317 4967 bi 19 0 0.65 0.052 5.1 29 0 27 6.8 103 table 5. continued g eologia c roatica velojić et al.: trace elements in pyrite from the čukaru peki porphyry cu-high-sulfidation deposit, serbia: implications for ore evolution in a polyphase ... 311 trations are the highest in the anhydrite-vein pyrite crystals with 104 μg/g. sulfide-vein pyrite crystals have the lowest median co and ni concentrations (3.6 and 0.45 μg/g respectively) of all the porphyry zone pyrite crystals. the co concentrations are in fact more similar to that of pyrite-enargite vein pyrite (median 5.3 μg/g) in the high-sulfidation zone, although this pyrite has a higher median ni concentrations (2.3 μg/g). selenium is generally enriched in the porphyry zone pyrite, but sulfide-vein pyrite contains the lowest median se concentrations (<4.1 μg/g) out of all the pyrite populations measured, with 16 out of 25 measurements showing values for se that are below detection limits. pyrite1 is the only pyrite type specifically found in two zones, the transition and high-sulfidation zones. this is evident in the trace element concentrations, as they have relatively similar median values in several of the measured elements (co, cu, se, cd and hg). accordingly, pyrite1 from the high-sulfidation zone is significantly enriched in a range of elements: v, cr, mn, ni, as, sn, sb, au, tl, pb and bi. thus, the high-sulfidation pyrite1 and pyrite from the pyrite-enargite vein shows the typical high-sulfidation trace element enrichment trend (eg. sykora et al.,2018), compared to the trend of the transition zone. silver, au, pb and bi in pyrite1 crystals show the lowest concentrations of all the high-sulfidation zone pyrite (median 1.2, 0.60, 1.5 and 0.65 μg/g respectively). these concentrations are still slightly, to significantly, higher than the porphyry zone pyrite median values. the high-sulfidation pyrite-covellite veins are the most trace element-rich veins (e.g. cu, ag, au and pb) of the čukaru peki ore system and are considered to be paragenetically the last veins formed, of those veins analyzed in this study (as demonstrated in figs.4b and 4c). pyrite-covellite veins are significantly enriched in cu, mo, ag, cd, in, sn, sb, au, hg, tl, pb and bi, even in comparison to the other high-sulfidation zone pyrite that are also commonly enriched in these elements. pyrite-covellite veins are the only vein type with substantial cd concentrations (median 5.9 μg/g), only 9 out of 29 measurements showing values below detection limits. the only other cd measurements above detection limit are 5 (out of 65) spot measurements from the porphyry zone. 5. discussion 5.1. stages of mineralization there are distinct mineralogical differences between the three zones of mineralization in the čukaru peki hydrothermal system. the upper zone consists of massive sulfides with pyrite-enargite and pyrite-covellite veins. the transitional epithermal zone consists of a system of anhydrite and gypsum veins, whereas the main ore minerals in this zone are covellite, chalcopyrite, digenite and enargite with occasional native sulfur. mineralization in the lower zone is mostly hosted by quartz and anhydrite veins with chalcopyrite, pyrite, bornite, magnetite, and pyrrhotite as the main ore minerals. ore microscopic examinations of samples from the upper zone mineralization (high-sulfidation zone) of čukaru peki imply that this zone was formed in several successive stages: 1) massive pyrite (py1); 2) py-en veins with pyrite and enargite; 3) py-cov veins with pyrite, covellite and enargite; 4) py2 veins with fine-grained pyrite and 5) marcasite veins with arsenopyrite and sphalerite. the research conducted by velojić et al. (2020) implies that the lower zone mineralization at čukaru peki formed in two successive stages. the porphyry stage formed at temperatures between 600 and 400°c and consists of four types of veins: 1) quartz veins type a without mineralization; 2) quartz veins type b with chalcopyrite, pyrite and bornite; 3) pyrite veins type d with subordinate chalcopyrite and bornite and 4) magnetite veins with hematite, pyrrhotite and chalcopyrite. the younger epithermal stage formed at temperatures between 300 and 200°c and includes three types of veins: 1) purple anhydrite veins with pyrite, with subordinate chalcopyrite, covellite and enargite; 2) sulfide veins with pyrite and covellite and 3) orange anhydrite veins without mineralization. 5.2. zonal differences and trends in pyrite trace element composition several distinctions can be made between pyrite from the different mineralization zones of čukaru peki (fig.8). selenium and co concentrations are relatively high in the porphyry zone (maximum median value of co at 104 μg/g and se at 717 μg/g) and gradually decrease (minimum median value of co at 0.19 μg/g and se at 7.7 μg/g; fig.8a), whereas the opposite is observed for au, ag, as and cu, which are significantly enriched in pyrite from the high-sulfidation zone (fig.8c, 8d). notable trends are observed with ni and co concentrations (fig.8b), which are increased in purple anhydrite-veins and in transition zone pyrite, but are depleted in porphyry and high-sulfidation veins. figure 7. boxplot comparing concentrations of selected elements analyzed in this study. variation between vein-types from each ore zone is clearly visible. note: below detection limits have been replaced by half of the measurement’s individual detection limit, to enable representation of low values. see table 2. for detection limits. g eo lo gi a c ro at ic a geologia croatica 75/special issue312 čukaru peki pyrite demonstrates trace element distribution trends similar to pyrite from other porphyry-epithermal copper deposits (sykora et al., 2018). higher-temperature porphyrystage pyrite is generally poorer in trace elements compared to the later, lower-temperature epithermal-stage pyrite. sykora et al.(2018) show that pyrite crystals from the lihir (ladolam) au porphyry-epithermal deposit in papua new guinea, which formed during the earlier, higher-temperature porphyry-stage are enriched in co, ni and se, whereas the later, lower-temperature epithermal-stage is characterized by an enrichment in as, mo, ag, sb, au and tl in pyrite. decreased cu concentrations in the pyrite from the porphyry zone of čukaru peki can be explained by the fact that cu is usually bound in cu-bearing sulfides, including chalcopyrite and bornite (kesler et al., 2002; reich et al, 2013). several studies demonstrate that cu concentrations in pyrite are very low in the first stages of the porphyry deposits and then gradually increase in the subsequent stages (maydagán,et al., 2013; tan et al., 2021) and are especially elevated in high-sulfidation pyrite (franchini et al.,2015; sykora et al.,2018). selenium concentrations in high-sulfidation pyrite that are lower than in the porphyry pyrite at čukaru peki are unusual, as se is typically higher in high-sulfidation pyrite (keith et al.,2018; and references therein), although their data does show certain overlaps in pyrite se concentrations from porphyry to high-sulfidation deposits. anomalously low se concentrations in pyrite can be explained by the presence of mineral phases with preferred partitioning of se, such as selenides, galena or even chalcopyrite (keith et al., 2018; pass, 2010). selenium concentrations in chalcopyrite have not previously been investigated. lead-selenides (clausthalite) have solely been identified within the b-type vein of the porphyry ore zone at čukaru peki (fig. 6a). however, time-resolved count signals of pyrite from the significantly se-enriched b-type veins are smooth and suggest that se is hosted in the pyrite crystal lattice (or as nanoinclusions) rather than microinclusions of clausthalite. thus, it seems that the fluids responsible for the formation of b-type veins were significantly se-enriched, bearing both se-rich pyrite and clausthalite. other examples of pyrite from porphyry deposits with elevated se concentrations have been described, such as a porphyry cu deposit in the romanian metaliferi mountains (cioacă et al., 2014). gold preferably precipitates from the hydrothermal fluids under lower temperature conditions within the epithermal zone, rather than under porphyry higher temperature conditions (e.g. deditius et al., 2014; simmons, 2005; sykora et al., 2018). this is the same trend as observed in čukaru peki pyrite. pyrite from the čukaru peki porphyry zone has a median au concentration of 0.013 μg/g, with a third of the measurements falling below detection limits, compared to the median of 7.2 μg/g au in the high-sulfidation zone. decreased concentrations of au and ag in pyrite from the porphyry zone of čukaru peki can also be explained by the tendency of gold and silver to mainly concentrate in chalcopyrite and bornite in porphyry systems (kesler et al., 2002; cook et al., 2011; zwahlen et al., 2014). also, native au and electrum are relatively common accessory minerals in these systems (john et al.,2010; sillitoe, 2010). these accessory minerals are also observed in čukaru peki, as demonstrated in fig.6b, which implies that au and ag preferably formed native minerals in this system, instead of being incorporated in pyrite. recent studies have demonstrated that as-rich pyrite in porphyry systems can concentrate up to 800 ppm au (reich et al., 2013; cioacă et al.,2014), but this type of pyrite was not observed in the porphyry zone of čukaru peki. cobalt-nickel values correspond to pyrite of volcanic origin, according to campbell & ethier (1984). čukaru peki pyrite has cobalt concentrations between <1 and <200 μg/g, along with ni values of maximum 20 μg/g. these low co-ni concentrations are in agreement with other studies on pyrite trace element geochemistry (e.g. deditius et al., 2014; franchini et figure 8. median values of trace element concentration trends in pyrite from different mineralization zones in čukaru peki. the elements that are enriched in pyrite from the porphyry zone are coloured red, those that concentrate around the transition zone are coloured blue, whereas elements enriched in the high-sulfidation zone are coloured green. a) se concentrations in pyrite have a decreasing trend from the porphyry to epithermal stages; b) co tends to concentrate in pyrite from anhydrite-veins and in pyrite from the transition zone; c) ni is enriched in py1 pyrite, both from the transition zone and high-sulfidation zone ; d) au concentrations increase rapidly in pyrite from high-sulfidation stage; e) ag is also significantly enriched in pyrite from the high-sulfidation stage; f) cu concentrations exhibit a steady increase in pyrite from – the porphyry to the epithermal stages. g eologia c roatica velojić et al.: trace elements in pyrite from the čukaru peki porphyry cu-high-sulfidation deposit, serbia: implications for ore evolution in a polyphase ... 313 al., 2015; pass, 2010; reich et al., 2013), where co and ni concentrations range from tens to a few hundreds of μg/g. this suggests that porphyry pyrite predominately has hydrothermal trace element signatures, but may display inherited magmatic trends originating from the magmatic source of the mineralizing hydrothermal fluids. 5.3. indications of a poly-stage mineralizing fluid evolution by trace element geochemistry porphyry–high-sulfidation systems form by multiple pulses of hydrothermal fluids circulating through the overlying host rock, driven by underlying intrusions (sillitoe, 2010; ingebritsen & appold, 2012). pyrite in these systems commonly exhibits zoning associated with polyphase fluid evolution (sykora et al., 2018) and may thus have zones with trace element compositions related to the different phases of hydrothermal fluids (franchini et al., 2015). the epithermal stage in the evolution of porphyry systems is characterized by high-, intermediateor low-sulfidation veins (and alteration) that form under lower temperatures and salinities than earlier porphyry veins (john et al., 2010; sillitoe, 2010). in these later stages, hydrothermal events that overprint the porphyry-style ore commonly remobilize cu and au, since the original chalcopyrite-bornite minerals are dissolved. in this way, au and cu are introduced into epithermal systems (kesler et al., 2002; reich et al., 2013; gregory et al., 2013). this process is particularly interesting in high-sulfidation deposits, since they are genetically and spatially associated with underlying porphyry systems (kesler et al., 2002; sillitoe, 2010). in many highsulfidation systems, pyrite commonly contains invisible gold in the crystal lattice (chouinard et al., 2005; bogdanov & kuncheva, 2017), but in some cases it also contains significant amounts of crystal lattice-bound cu (pačevski et al.,2008). pokrovski et al. (2019) argue that chemisorption is the most common process in which invisible gold is incorporated into pyrite as au(i) ions. in čukaru peki, the polyphase genesis is evident from multiple generations of veins (tables 3 and 4; fig.5). the process of primary sulfide dissolution can be observed in the transition zone of čukaru peki, where covellite and enargite replace the primary mineralization of chalcopyrite and bornite. significantly elevated concentrations of elements are attributed to the high-sulfidation zone (e.g. cu, ag, cd, in, sn, pb and bi). five spot measurements of the porphyry zone pyrite crystals (b-type veins and purple anhydrite-veins) suggest that these veins were affected by later high-sulfidation fluids. the later fluids could have resulted in pyrite growth zones that would be enriched in these high-sulfidation associated elements. elevated cd is particularly interesting, as cd is only seen above detection limits in the pyrite-covellite veins, which represent the latest veins investigated in this study. this could indicate that the later hydrothermal fluids, responsible for the pyrite-covellite veins, originated from the deeper parts of the hydrothermal system. an additional argument for this statement is the apparent compositional similarity between sulfideveins (fig.5.h), which are found in the porphyry and transitional zones and pyrite-covellite veins (fig.5c) which are found in the high-sulfidation zone. both of these veins contain abundant covellite, which is a common mineral for the high-sulfidation zone, but uncommon for porphyry conditions (john et al., 2010; sillitoe, 2010). this suggests that sulfide-veins formed by the same or similar fluids that led to the remobilization of primary sulfides and redeposition in the high-sulfidation zone. pyrite from sulfide-veins differs from pyrite from py-cov veins, both in its textural characteristics (lack of colloform texture) and in its trace element composition (depleted concentrations of au, ag and cu). however, this can possibly be explained by the different temperatures at which these two vein types were formed, which probably affected the depositional textures and element distributions. duran et al. (2019) investigated pyrite trace element compositions from a range of deposit types (vms, orogenic au, porphyry cu and magmatic). based on this, duran et al. (2019) were able to distinguish pyrite from hydrothermal and magmatic origins based on their co/sb and se/as variations (fig. 9). čukaru peki pyrite from the porphyry zone (and transition zone) plot predominantly within the magmatic zone (marked with an orange colour), with overlaps into the hydrothermal zone , which is the case for the porphyry cu field in the duran et al. (2019) diagram. high-sulfidation zone (marked with a green colour) pyrite plots well within the hydrothermal domain proposed by duran et al. (2019). this is reasonable as the fluids responsible for the porphyry zone, especially, would have a significant magmatic signature. this is further demonstrated with fluid inclusion analyses by velojić et al. (2020). earlier and deeper porphyry zone veins, such as the b-type veins, show a more magmatic signature figure 9. discrimination plot for pyrite formed from hydrothermal or magmatic origins (indicated by the dashed line), based off se/as vs co/sb values. two domains are drawn out, based on where the porphyry and magmatic pyrite data clusters. plot and domains are made after duran et al. (2019). note: below detection limits have been replaced by half of the measurement’s individual detection limit, to enable representation of low values. see table 2. for the detection limits. g eo lo gi a c ro at ic a geologia croatica 75/special issue314 with homogenization temperatures between 331 and 495oc and salinities between 36.5 and 43 wt% nacl eq, whereas anhydrite veins were formed by fluids with significantly lower salinities. it is important to note that porphyry zone pyrite would not be expected to plot perfectly within the magmatic domain, as they are still the product of hydrothermal fluids. rather, the hydrothermal fluids responsible for the mineralization display a slight magmatic signature, inherited from the magmatic source. these pyrites were not formed in the magma itself and thus do not show a true magmatic signature. 6. conclusions the results obtained demonstrate that the different veins in čukaru peki can be distinguished by both their mineralogy and trace element compositions. the porphyry zone pyrite crystals generally contain lower concentrations of most trace elements and are only significantly enriched in co and se. transition pyrite mostly shows trace element concentrations between the two other zones, having lower concentrations more similar to pyrite from the porphyry zone. high-sulfidation pyrite crystals are characterized by enrichment of v, mn, ni, cu, as, mo, ag, cd, in, sn, sb, au, hg, tl, pb and bi. increased concentrations of elements attributed to the high-sulfidation zone in five spot measurements of the porphyry zone pyrites crystals from quartz veins type b and purple anhydrite veins imply that these veins were affected by later high-sulfidation fluids. however, there are many differences in trace element concentrations between the different pyrite crystals of each zone. the ore-microscopic and sem studies imply that the most important stage for the deposition of cu and au in the porphyry system was quartz veins type b. these veins contain the highest amounts of cu-bearing sulfides (chalcopyrite and bornite). additionally, sem studies have demonstrated the presence of native au and electrum grains in these veins (fig.6b and 6d). concentrations of au and ag in pyrite are low, which indicates that these two elements formed native minerals (native au and electrum) or were partitioned into chalcopyrite or bornite. another important type of vein for cu deposition are the sulfide veins, which contain abundant covellite and probably represent the transition to the epithermal stage of mineralization. according to the ore-microscopic research and la-icp-ms measurements, we conclude that the most important stage for the deposition of cu and au in the high-sulfidation zone are the pyritecovellite (py-cov) veins. they contain the highest amounts of cusulfides (covellite and enargite) as well as the highest concentrations of au and ag in the analyzed pyrite grains. pyrite-enargite veins also contain abundant enargite, but much less covellite than the pyrite-covellite veins, thus they have lower cu contents. however, it should be noted that preliminary measurements indicate that enargite from pyrite-enargite veins contains elevated concentrations of germanium (velojić & erlandsson, 2019). our pyrite trace element data illustrates the change in mineralizing hydrothermal fluids; from a magmatic-sourced system (the porphyry zone) to a more typical hydrothermal system that was responsible for the high-sulfidation zone mineralization. there is also evidence for the late high-sulfidation fluids affecting the earliest and deeper pyrite in the porphyry zone, by growth of pyrite enriched in elements characteristic of the high-sulfidation mineralization. it is established that the main gold-concentrating mineral in this zone is pyrite, which is commonly not considered an ore mineral during mineral processing and thus it is usually not included in the main sulfide concentrate. the results presented might also be significant for the better targeting of specific goldand silverrich veins and mineralization stages during mineral exploration. acknowledgement this contribution is supported by the project “reseerve mineral potential of the esee region” funded by the european institute of innovation and technology (eit), a body of european union, under the horizon 2020, the eu framework programme for research and innovation. the authors would like to thank the geologists from the rakita exploration company for their assistance in sampling and geological interpretation (now called balkan expploration and mining). this research was partly funded with an ernst mach grant by oead agency and with ceepus mobility grant. two anonymous reviewers and the editor are thanked for their constructive comments in improving the manuscript. references banješević, m. & large, d. (2014): geology and mineralization of the new copper and gold discovery south of bor timok magmatic complex.– in: proceedings of the xvi serbian geological congress, serbian geological society, donji milanovac, 2014, 739–741. banješević, m., cvetković, v., von quadt, a., ljubović obradović, d., vasić, n., pačevski, a. & peytcheva, i. (2019): new constraints on the main mineralization event inferred from the latest discoveries in the bor metallogenetic zone (bmz, east serbia).– minerals, 9/11, 672. https://doi.org/10.3390/ min9110672 bogdanov, k., & kuncheva, j. (2017): epithermal gold mineralization in the krassen deposit, panagyurishte ore district, bulgaria.– geologica macedonica, 31/2, 107–116. campbell, f.a. & ethier, v.g. (1984): nickel and cobalt in pyrrhotite and pyrite from the faro and sullivan ore bodies.– the canadian mineralogist, 22, 503–506. chouinard, a., paquette, j. & williams-jones, a.e. (2005): crystallographic controls on trace-element incorporation in auriferous pyrite from the pascua epithermal high-sulfidation deposit, chile–argentina.– the canadian minera logist, 43/3, 951–963. doi: 10.2113/gscanmin.43.3.951 cioacă, m.e., munteanu, m., qi, l. & costin, g. (2014): trace element concentrations in porphyry copper deposits from metaliferi mountains, romania: a reconnaissance study.– ore geology reviews, 63, 22–39. doi: 10.1016/j.oregeorev.2014.04.016 cook, n.j., ciobanu, c.l., danyushevsky, l.v. & gilbert, s. (2011): minor and trace elements in bornite and associated cu–(fe)-sulfides: a la-icp-ms study bornite mineral chemistry.– geochimica et cosmochimica acta, 75/21, 6473–6496. doi: 10.1016/j.gca.2011.08.021 deditius, a.p., reich, m., kesler, s.e., utsunomiya, s., chryssoulis, s.l., walshe, j. & ewing, r.c. (2014): the coupled geochemistry of au and as in pyrite from hydrothermal ore deposits.– geochimica et cosmochimica acta, 140, 644–670. doi: 10.1016/j.gca.2014.05.045 drovenik, m. (1961): geological-petrological study of the bor mine area (eastern serbia) (in slovenian).– unpubl. phd theses, ljubljana, 344 p. duran, c.j., dubé-loubert, h., pagé, p., barnes, s.-j., roy, m., savard, d. cave, b.j., arguin, j.-p. & mansur, e.t. (2019): applications of trace element chemistry of pyrite and chalcopyrite in glacial sediments to mineral exploration targeting: example from the churchill province, northern quebec,– canada journal of geochemical exploration, 196, 105–130. doi: 10.1016/j.gexplo.2018.10.006 franchini, m., mcfarlane, c., maydagán, l., reich, m., lentz, d.r., meinert, l. & bouhier, v. (2015): trace metals in pyrite and marcasite from the agua rica porphyry-high sulfidation epithermal deposit, catamarca, argentina: textural features and metal zoning at the porphyry to epithermal transition.– ore geology reviews, 66, 366–387. doi: 10.1016/j.oregeorev.2014.10.022 fügenschuh, b. & schmid, s.m. (2005): age and significance of core complex formation in a very curved orogen: evidence from fission track studies in the south carpathians (romania).– tectonophysics, 404/1–2, 33–53. doi: 10.1016/j.tecto.2005.03.019 gallhofer, d., quadt, a. v., peytcheva, i., schmid, s. m., & heinrich, c.a. (2015): tectonic, magmatic, and metallogenic evolution of the late cretaceous arc in the carpathian-balkan orogen.– tectonics, 34/9, 1813–1836. doi: 10.1002/2015tc003834 gregory, m.j., lang, j.r., gilbert, s. & hoal, k.o. (2013): geometallurgy of the pebble porphyry copper-gold-molybdenum deposit, alaska: implications for gold distribution and paragenesis.– economic geology, 108/3, 463–482. doi: 10.2113/ econgeo.108.3.463 g eologia c roatica velojić et al.: trace elements in pyrite from the čukaru peki porphyry cu-high-sulfidation deposit, serbia: implications for ore evolution in a polyphase ... 315 ingebritsen, s.e. & appold, m.s. (2012): the physical hydrogeology of ore deposits.– economic geology, 107/4, 559–584. doi: 10.2113/econgeo.107.4.559 jakubec, j., macsporran, g., duinker, p., pittuck, m., manoljović, p., sucharda, m., samouković, m., bunyard, c. & arseneau, g. (2018): ni 43-101 technical report-timok copper-gold project, serbia: upper zone prefeasibility study and resource estimate for the lower zone.– nevsun resources ltd, 1–427. janković, s. (1990): the ore deposits of serbia (yugoslavia): regional metallogenic setting, enviroments of deposition and types (in serbian, with english summary).– faculty of mining and geology, belgrade, 760 p. janković, s., jelenković, r. & кoželj, d. (2002): the bor copper and gold mine.– qwеrтy, bor, 298 p. jelenković, r., milovanović, d., koželj, d. & banješević, m. (2016): the mineral resources of the bor metallogenic zone: a review.– geologia croatica, 69/1, 143–155. doi: 10.4154/gc.2016.11 john, d.a., ayuso, r.a., barton, m.d., blakely, r.j., bodnar, r.j., dilles, j.h., gray, f., graybeal, f.t., mars, j.l., mcphee, d., seal, r.r. & taylor, r.d. (2010): porphyry copper deposit model.– scientific investigations report. doi: 10.3133/sir20105070b keith, m., smith, d.j., jenkin, g.r.t., holwell, d.a. & dye, m.d. (2018): a review of te and se systematics in hydrothermal pyrite from precious metal deposits: insights into ore-forming processes.– ore geology reviews, 96, 269–282. doi: 10.1016/j.oregeorev.2017.07.023 kesler, s.e., chryssoulis, s.l. & simon, g. (2002): gold in porphyry copper deposits: its abundance and fate.– ore geology reviews, 21/1–2, 103–124. doi: 10.1016/s0169-1368(02)00084-7 knaak, m., márton, i., tosdal, r. m., van der toorn, j., davidovic, d., strmbanovic, i. & hasson, s. (2016): geologic setting and tectonic evolution of porphyry cu-au, polymetallic replacement, and sedimentary rock-hosted au deposits in the northwestern area of the timok magmatic complex, serbia.– serbia, society of economic geologists, special publication, 19, 1–28. kolb, m., von quadt, a., peytcheva, i., heinrich, c.a., fowler, s.j. & cvetković, v. (2013): adakite-like and normal arc magmas: distinct fractionation paths in the east serbian segment of the balkan–carpathian arc.– journal of petrology, 54/3, 421–451. doi: 10.1093/petrology/egs072 maydagán, l., franchini, m., lentz, d., pons, j. & mcfarlane, c. (2013): sulfide composition and isotopic signature of the altar cu-au deposit, argentina: constraints on the evolution of the porphyry-epithermal system.– the canadian mineralogist, 51/6, 813–840. doi: 10.3749/canmin.51.6.813 mišković, v. (1989): the genesis of copper deposit “novo okno” and its metallogenic corellation with ore clasts in bor regioneastern serbia (in serbian).– unpubl. phd theses, faculty of mining and geology, belgrade, 189 p. neubauer, f. (2002): contrasting late cretaceous with neogene ore provinces in the alpine-balkan-carpathian-dinaride collision belt.– geological society london special publication, 204, 90–100. doi: 10.1144/gsl.sp.2002.204.01.06 onuk, p., melcher, f., mertz‐kraus, r., gäbler, h.e. & goldmann, s. (2017): development of a matrix‐matched sphalerite reference material (mul‐ zns‐1) for calibration of in situ trace element measurements by laser ablation‐inductively coupled plasma‐mass spectrometry.– geostandards and geoanalytical research, 41/2, 263–272. doi: 10.1111/ggr.12154 pačevski, a., libowitzky, e., živković, p., dimitrijević, r. & cvetković, l. (2008): copper-bearing pyrite from the čoka marin polymetallic deposit, serbia: mineral inclusions or true solid-solution?.– the canadian mineralogist, 46/1, 249–261. doi: 10.3749/canmin.46.1.249 pačevski, a., cvetković, v., šarić, k., banješevć, m., hoefer, h.e. & kremenović, a. (2016): manganese mineralization in andesites of brestovačka banja, serbia: evidence of sea-floor exhalations in the timok magmatic complex. mineralogy and petrology, 110/4, 491. doi: 10.1007/s00710-016-0425-7 pass, h.e. (2010): breccia-hosted chemical and mineralogical zonation patterns of the northeast zone, mt. polley cu-ag-au alkalic porphyry deposit, british columbia, canada.– phd thesis, university of tasmania. paton, c., hellstrom, j., paul, b., woodhead, j. & hergt, j. (2011): iolite: freeware for the visualisation and processing of mass spectrometric data.– journal of analytical atomic spectrometry. doi:10.1039/c1ja10172b. pavićević, m., rakić, s., gržetić, i. & golijanin, d. (1981): a study of distribution of precious, rare and trace elements in the ore body “tilva roš” in bor mine (in serbian).– faculty of mining and geology ulema, belgrade, 102 p. pavićević, m., rakić, s., gržetić, i. & golijanin, d. (1985): a study of distribution of precious, rare and trace elements in the borska reka ore deposit (in serbian).– faculty of mining and geology ulema, belgrade, 112 p. pokrovski, g.s., kokh, m.a., proux, o., hazemann, j.l., bazarkina, e.f., testemale, d., ... & thibaut, m. (2019): the nature and partitioning of invisible gold in the pyrite-fluid system.– ore geology reviews, 109, 545–563. doi: 10.1016/j.oregeorev.2019.04.024 reich, m., deditius, a., chryssoulis, s., li, j. w., ma, c.q., parada, m.a., ... & mittermayr, f. (2013): pyrite as a record of hydrothermal fluid evolution in a porphyry copper system: a sims/empa trace element study.– geochimica et cosmochimica acta, 104, 42–62. doi: 10.1016/j.gca.2012.11.006 sillitoe, r.h. (2010): porphyry copper systems.– economic geology, 105/1, 3–41. doi: 10.2113/gsecongeo.105.1.3 simmons, s.f. (2005): geological characteristics of epithermal precious and base metal deposits.– in: 100th anniversary volume, 485–522. doi: 10.5382/av100.16 sykora, s., cooke, d. r., meffre, s., stephanov, a. s., gardner, k., scott, r., ... & harris, a.c. (2018): evolution of pyrite trace element compositions from porphyry-style and epithermal conditions at the lihir gold deposit: implications for ore genesis and mineral processing.– economic geology, 113/1, 193–208. doi: 10.5382/econgeo.2018.4548 vakanjac, b. (2000): a comparative study of typical paragenetic relations in different ore of bor metallogenic zone (in serbian)– doctoral dissertation, faculty of mining and geology, belgrade, 314 p. velojić, m. & bertrandsson erlandsson, v. (2019): trace elements in different veins by la-icp-ms in chukaru peki high sulfidation deposit, serbia.– in: 1st international student conference on geochemistry and mineral deposits, prague. velojić, m., jelenkovic, r. & cvetkovic, v. (2020): fluid evolution of the čukaru peki cu-au porphyry system (east serbia) inferred from a fluid inclusion study.– geologia croatica, 73/3, 197–209. doi: 10.4154/gc.2020.14 von quadt, a. peytcheva, i., cvetković, v. banješević, m. & koželj, d. (2002): geochronology, geochemistry and isotope tracing of the cretaceous magmatism of east-serbia as part of the apuseni-timok-srednogorie metallogenic belt.– geologica carpathica, 53, 175–177. wilson, s.a., ridley, w.i. & koenig, a.e. (2002): development of sulfide calibration standards for the laser ablation inductively-coupled plasma mass spectrometry technique.– international journal of analytical atomic spectrometry, 17, 406–409. doi: 10.1039/b108787h zwahlen, c., cioldi, s., wagner, t., rey, r. & heinrich, c. (2014): the porphyry cu-(mo-au) deposit at altar (argentina): tracing gold distribution by vein mapping and la-icp-ms mineral analysis.– economic geology, 109/5, 1341–1358. doi: 10.2113/econgeo.109.5.1341 g eo lo gi a c ro at ic a geologia croatica 75/special issue316 2022 | 75/1 | 1–2 | 1 fig. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society dear readers, this issue, 75/1 is mostly dedicated to the environmental impact of landslides, which, due to current climate change, are becoming more and more pronounced around the world and in the republic of croatia. the six papers (bostjančić et al., 2022, fig. 1 poly­ gon 1; filipović et al., 2022, fig. 1 polygon 2; frangen et al., 2022, fig. 1 polygon 3; gulam et al., 2022, fig. 1 polygon 4; podolszki et al., 2022, fig. 1 polygon 5; pollak et al., 2022, fig. 1 polygon 6) focusing on landslides are the result of the work of a large team of people from the croatian geological sur­ vey, carried out within the framework of the safearth project, cofinanced by the erdf and ipa ii funds of the european union. as a part of the interreg ipa – cross-border cooperation programme croatia – bosnia and herzegovina – montenegro 2014-2020, the safearth project was based on cross-border coop­ eration of four partner institutions, namely the croatian geological survey (lead partner), geological survey of montenegro, faculty of mining, geology and civil engineering of the univer­ sity of tuzla and the development agency žepče d.o.o. the main project activities were focused on landslide susceptibility maps (lsm) as one of the most important data sets in spatial planning the use of high-resolution lidar scanning in the research of small landslides based on croatian examples doi: 10.4154/gc.2022.13 that have not been recognized as such in any of the project part­ ner countries. lsms show the subdivision of the terrain into zones that have a similar spatial probability of landslide occurrence (coro­ minas et al., 2014). their derivation is usually based on the principle that the past is a guide to the future, i.e., areas similar to those that have experienced landsliding in the past are likely to experience landsliding in the future (varnes, 1984). for de­ termination of past landslide activity within a certain area, it is crucial to establish and further analyse the landslide inventory (fell et al., 2008). the articles presented in this issue represent pioneering at­ tempts at establishing and analysing landslide inventories within six pilot polygons distributed in three croatian counties, namely zagreb, sisak-moslavina, and brod-posavina (fig. 1). the poly­ gon positioning principle was determined to cover as many geo­ logical units within these counties as possible. the aim was to quantify their landslide susceptibility, which was the general goal for all six of the presented papers. it is crucial to emphasize that all presented landslide inven­ tories are lidar-based and derived from a 0.5 m resolution difig. 1 spatial distribution of the study polygons on the geological map of the republic of croatia m 1: 300.000 (hgi, 2009) g eo lo gi a c ro at ic a geologia croatica 75/12 gital terrain model. additionally, high­resolution orthophoto maps with approximately 10 cm ground sampling distances were also used. the characteristics of the remote data used are de­ scribed in more detail in each of the six presented papers. still, it is important here to point out that these data cover an area of approximately 310 km2, and that landslide inventories are pre­ pared for the entire scanned area. references bostjančić, i., avanić, r., frangen, t. & pavić, m. (2022): spatial distribu­ tion and geometric characteristics of landslides with special reference to geologi­ cal units in the area of slavonski brod, croatia. doi: 10.4154/gc.2022.03 corominas, j., van westen, c., frattini, p., cascini, l., malet, j.-p., fotopoulou, s., catani, f., van den eeckhaut, m., mavrouli, o., agliardi, f., pitilakis, k., winter, m.g., pastor, m., ferlisi, s., tofani, v., herva´s, j. & smith, j.t. (2014): recommendations for the quan­ titative analysis of landslide risk.– bulletin of engineering geology and the envi­ ronment, 73, 209–263. doi: 10.1007/s10064-013-0538-8 fell, r., corominas, j., bonnard, c., cascini, l., leroi, e. & savage, w.z. (2008): guidelines for landslide susceptibility, hazard and risk zoning for land use planning.– engineering geology, 102/3–4, 85–98. doi: 10.1016/j. enggeo.2008.03.022 filipović, m., mišur, i., gulam, v. & horvat, m. (2022): a case study in the research polygon in glina and dvor municipality, croatia-landslide susceptibility assessment of geological units. doi: 10.4154/gc.2022.04 frangen, t., pavić, m., gulam, v. & kurečić, t. (2022): use of lidar-de­ rived landslide inventory map in assessing influencing factors for landslide sus­ ceptibility of geological units in the petrinja area (croatia). doi: 10.4154/gc.2022.10 gulam, v., bostjančić, i., hećej, n., filipović, m. & filjak, r. (2022): preliminary analysis of lidar-based landslide inventory in the area of samobor, croatia. doi: 10.4154/gc.2022.11 podolszki, l., kurečić, t., bateson, l. & svennevig, k. (2022): remote landslide mapping, field validation and model development – an example from kravarsko, croatia. doi: 10.4154/gc.2022.01 pollak, d., hećej, n. & grizelj, a. (2022): landslide inventory and characteris­ tics, based on lidar scanning and optimised field investigations in the kutina area, croatia. doi: 10.4154/gc.2022.02 varnes, d.j. & iaeg (1984): landslide hazard zonation: a review of principles and practice. unesco, paris, 63 p. kenan mandžić, guest editor vlatko gulam, guest editor lidija galović, editor-in-chief 1. introduction in the literature there are many suggestions how to make distinction between different potassium feldspar “mineral species”, but the international mineralogical association (ima) recommends three terms: “sanidine”, “orthoclase” and “microcline” (barth, 1934). “microcline” (k>>na)alsi3o8 is the low-temperature phase. the crystal structure is triclinic c1̄ with four crystallographic tetrahedral (t) sites with an ordered si, al distribution. orthoclase has monoclinic c2/m symmetry, according to the disordered distribution of al and si between the four t sites. mineral species and mineral varieties can be characterized by various techniques. under equilibrium conditions, laves & goldsmith (1961) distinguishes the following k-feldspars: low microcline, intermediate microcline and high microcline. based on x-ray powder diffraction (xrpd), ribbe (1983) classifies them as low microcline, intermediate microcline and orthoclase. using selected area (electron) diffraction (saed), bambauer et al. (1989) identified k-feldspars based on their scattering characteristics in [001] zone projection, as a) regular microcline twinning, a (albite law) and p (pericline law) twins spot splitting; b) irregular twinning microcline (a and p twins spot splitting and diffuse streaks; and c) tweed (domains) orthoclase (a and p twins diffuse streaks). stewart & ribbe (1983) distinguished optical microcline (dd0d) and optical orthoclase (d=0d) by polarized light optical microscopy (plom) according to the extinction angle d in (001) sections. according to sánchez-muñoz et al. (2012) microcline is characterized by a low crystallization temperature, triclinic symmetry and ordered si, al distribution, while orthoclase is metastable microstructures of feldspar crystals from pakra creek valley granite (papuk mt., croatia) marija horvat1,*, viktória kovács kis2 and jasmina martinčević lazar1 1 croatian geological survey, department of geology, sachsova 2, 10000 zagreb, croatia; (jmartincevic@hgi-cgs.hr; *corresponding author: mhorvat@hgi-cgs.hr) 2 hun-ren centre for energy research, konkoly-thege miklós út 29-33, h-1121, budapest, hungary; (kis.viktoria@ek.hun-ren.hu) doi: 10.4154/gc.2025.06 abstract optical polarizing microscopy, x-ray powder diffraction and transmission electron microscopy with energy-dispersive spectroscopy have been used to study microstructures in feldspars from two structurally and texturally different granite types from pakra creek valley (papuk mt., croatia). the porphyritic texture granite contains pink potassium feldspar megacrysts with cross-hatched extinction and tweed pattern, which proved to be intermediate microcline to orthoclase. these crystals have or > 90% and an=0 composition, and coexist with low albite or(1.2)ab(98.8)an(0). the feldspars from the granite with homogenous finegrained microstructure are white in colour and proved to be mixture of lamellar and zoned plagioclase and intermediate microcline. the plagioclase has a na:ca ratio close to 3:1 and minor k content (72.2%<ab<76.5%, 23%<an<26.8%, or<1.4%). pure albite (ab=97-99%) and anorthite (an=99%) grains were also detected. the higher content of plagioclase in the granite with homogenous fine-grained microstructure indicates a higher crystallization temperature compared to the porphyritic type. the microstructure of the feldspar crystals suggests a parent melt close to the eutectic composition for the studied granites. having triclinic-like symmetry, with partially ordered si, al distribution, which leads to the formation of modulations in structural strain. the same authors highlight the significance of a high content of chemical hinderers in orthoclase, which act as a barrier to structural ordering. the fine grainsize of granite webber et al. (1999) connected to a drop in pressure and rapid cooling at high crustal levels (rockhold et al., 1987). willaime et al. (1976) described a complete list of potassium feldspar microstructures depending on the melt composition and cooling rate. potassium feldspar megacrysts are very common in granitic rocks, being either triclinic microcline or monoclinic orthoclase. kerrick (1969) firstly expressed an opinion that potassium feldspar megacrysts crystallize from the melt in the early phase of magma solidification compared to the groundmass microcline. vernon (1986), bateman (1992) and cox et al. (1996) later confirmed this theory. vernon (1986) and cox et al. (1996) linked ba-oscillatory zoning in potassium feldspar megacrysts to their igneous crystallization. dickson & sabine (1967) and johnson et al. (2006a, b) attributed their crystallization to a late water-rich fluid phase under subsolidus conditions as porphyroblasts and replacement of other mineral grains. collins & collins (2002, and references therein) suggested microcline replacements of plagioclase and formation of myrmekite due to the influence of potassium bearing fluids. coleman et al. (2005) and glazner et al. (2004) reported that a porphyroblastic origin is necessary in the post solidification phase, and that the igneous origin of the megacrysts is compatible with the host pluton. glazner et al. (2004) also introduced the term “big tank” 2025 | 78/1 | 45–60 | 7 figs. | 2 tabs. | 2 suppls. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society article history: manuscript received: november 15, 2024 revised manuscript accepted: january 21, 2025 available online: february 27, 2025 keywords: microstructure, feldspar, granite, pakra creek valley, papuk mt., croatia mailto:jmartincevic@hgi-cgs.hr mailto:mhorvat@hgi-cgs.hr mailto:kis.viktoria@ek.hun-ren.hu g eo lo gi a c ro at ic a 46 geologia croatica 78/1 crystallizing reservoir of magma and gave examples that the potassium feldspars mostly grow after the magma crosses the rheological lock-up threshold of ≈ 50% crystals (glazner & johnson, 2013). further, the same authors stated that the high potassium composition of megacrysts and their large size possibly required growth temperatures below the nominal solidus temperatures of ≈ 650 °c and exsolution of ab (albite) component down to temperatures of ≈ 400 °c. brown & parsons (1989) and parsons et al. (2015), discusses exsolution and twin microstructures in alkali feldspars in relation to their thermal history including behaviour during diagenesis and weathering. they also emphasize that phase equilibria and thermodynamics of reactions should be considered as appropriate, i.e. taking into account the effect of interfaces and particle size and stability in oxide-bearing systems (navrotsky et al., 2008; navrotsky, 2011; kontonikas-charos et al., 2018). the first report about alkali feldspar megacrysts from pakra creek (papuk mt., croatia) was given in kučan & krmpotić (1911). they described them in a gneiss host as "microcline-microperthites". poljak (1952) mentioned up to 5 cm feldspar crystals in the pakra creek valley granites. the "large pink microcline" crystals from pegmatitic pockets (sloboština creek) and granitic veins (pakra creek) were later studied by tajder (1957). the megacrysts in adamellite and granodiorite of west papuk mt. as porphyritic and vein filling, diffuse, metasomatic k-feldspar megacrysts were described by vragović (1965). two types of megacrysts, vein filling (pakra creek, papuk mt.) and pocket forming (sloboština creek, papuk mt.), were studied by kovács kis et al. (2004), and proved to be low microcline in association with low albite and quartz. the alkali feldspar megacryst from pakra creek was characterised by the absence of twinning, while the megacryst from sloboština creek showed a tweed-like texture (kovács kis et al., 2004). the deduced crystallization temperatures were below 460 °c, and near to but above 460 °c, respectively. these low microcline megacrysts are characterised by a continuously modulated lattice on the submicroscopic scale. the main aim of this paper is determining the type of feldspars and their microstructure in two different granite types (sample 2ppg-4, the porphyritic, and ppg-24 the homogeneous type), both from pakra creek valley, papuk mt. (fig. 1). these two different types of feldspar host rocks were chosen for this study, which are representative of granites in the pakra creek valley and associated with pegmatite occurrence described in kovács kis et al. (2004). these results will be useful for the further study of a series of granites and associated migmatite and metamorphic samples, and will provide details of the geological history of the area. 2. methods the chemical and structural inhomogeneity of the feldspar grains were measured using a polarizing microscope (pm), x-ray powder diffractometer (xrpd) and a transmission electron microscope (tem). the modal composition was determined using a polarizing microscope zeiss axio lab a1 equipped with an ocular net and zeiss axiocam 105 digital camera with software zen at figure 1. the sampling localities (blue circles) in the pakra creek valley (papuk mt.) on the compiled geological map of slavonian mts. (jamičić, 2001) and their position within the tisza mega-unit on the tectonic map of schmid et al. (2020). lithology legend for the geological map: pk – chlorite-sericite schist, metagabbro, marble, amphibolite, amphibole schist, phlaseride granitoid, garnet-staurolite gneiss; mi – migmatite; gbm – garnet-biotitemuscovite gneiss; + granitoids (symbol from horvat, 2004); d,c – graphitic schist, conglomerate, sandstone; pt – quartz sandstone, conglomerate; t1 – sandstone, siltstone, shale; t2-3 – dolomite, dolomitic limestone; j1-3 – limestone; m2 – conglomerate, sand, gravel; m3 – conglomerate, sand, clay and marl; m4 – conglomerate, limestone, marl; m5-6 – marl and limestone; m7 – sand, marl and clay; c – albite rhyolite, andesite, basalt; pl,q – gravel and sands; lq1 – loess; dprq2 – deluvial-proluvial deposits; aq2 – alluvium of creeks. g eologia c roatica 47horvat et al.: microstructures of feldspar crystals from pakra creek valley granite (papuk mt., croatia) the department of geology of croatian geological survey. the value of standard deviations of repeated measurements was below 3%. the x-ray powder diffraction (xrpd) measurements of crystals extracted from the granite rock (grains a and b, sample 2ppg-4) and non-magnetic, low density fraction of whole rock ppg-24 sample, were performed on a siemens 0500 powder diffractometer (cu radiation, 40kv, 20 ma, analogous registration at 0.5° 2q/min goniometer speed), at the department of mineralogy of eötvös loránd university. for the d-value measurements, the reflections of accompanying quartz (pdf 00-033-1161) were used as an inner standard. the x-ray powder diffraction (xrpd) measurements were performed additionally for megacrysts (grain c) and a whole rock sample 2ppg-4 with a panalytical x' pert pro diffractometer at the department of geology, croatian geological survey (cu-tube, graphite monochromator and pixel detector; experimental conditions: 45 kv, 40 ma, pw 3018/00 pixcel detector, primary beam divergence 1°, and continuous scan step 0.02° 2θ/s). the program x’pert highscore plus (panalytical, 2016) was used, which contains powder diffraction database pdf 4/ minerals (international centre for diffraction data, 2024). powder samples for tem were prepared from large sized crystals which appear to be homogeneous both with the naked eye and under an optical microscope. special attention was paid to select pieces that could be considered representative of the large, macroscopic crystals. however, the presence of a minor, non-representative sample volume in the tem spe cimen cannot be ruled out. therefore, for saed and (hr)tem analysis, only such grains were used, which proved to be the major component based on the comparison of tem-eds and xrd data. the samples for tem observations were obtained by grinding the sample under ethanol and mounting a drop from the suspension onto a cu-grid covered by amorphous carbon supporting film. tem study was done at the hun-ren centre for energy research, budapest, hungary, using a themis (thermofisher) tem, operated at 200 kv and equipped with cs (spherical aberration) correction in the imaging system (spatial resolution in hrtem mode 0.8 å). the microscope is equipped with a figure 2. a) the sample 2ppg-4 image; b, c) photomicrographs of porphyritic structure sample 2ppg-4, xpl – cross-polarized light; b) the microcline, plagioclase, quartz, biotite, muscovite presence and myrmekite occurrence; c) alkali feldspar cross-hatched extinction pattern; perfect cleavage along {001}, good cleavage along {010} are observed. right angle cleavage is characteristic; both twin systems extinct simultaneously; d) the sample ppg-24 image; e, f) photomicrographs of the homogeneous structured ppg-24 sample, xpl – cross-polarized light; e) the orthoclase, plagioclase, quartz, biotite and muscovite presence; f) plagioclase exhibits compositional zonation as well. abbreviations are according warr (2021): bt – biotite, mcc – microcline, ms – muscovite, or – orthoclase, pl – plagioclase and qz – quartz. diameter of the coin is 1.6 cm. g eo lo gi a c ro at ic a 48 geologia croatica 78/1 schottky field emission gun (feg) having an energy spread of 0.7 ev. saed patterns were taken from an area of 600 nm diameter and recorded using a 4kx4k ceta camera and velox software (thermo fisher). offline analysis of saed patterns and fast fourier transform (fft) analysis of high resolution (hr)tem images was undertaken with velox software (thermo fisher) and crisp software (calidris, sollentuna, sweden) (hovmöller, 1992). calculation of saed patterns was done using the singlecrystal 4.1.7 software (crystalmaker software limited, begbroke, uk). 3. results the sample 2ppg-4 contains pink feldspar megacrysts measuring up to 2x1 cm size, and this granite has a porphyritic texture (fig. 2a). besides the pink megacrysts, a white mineral, hypidiomorphic to allotriomorphic in shape is also considered to be a feldspar. the sample contains biotite flakes and grey quartz grains. biotite is a few mm and quartz is up to 1 cm in size (fig. 2a). the second granite sample ppg-24 has a homogeneous structure and is composed of grains with a uniform grain size distribution measuring from 1 to 5 mm (fig. 2d). the sample contains grey quartz, black biotite and white minerals, assumed to be feldspars of different cross-section sizes (fig. 2d). the porphyritic granite with pink megacrysts (sample 2ppg-4) has the following modal composition: microcline 32%, orthoclase 8%, plagioclase 43%, quartz 8%, biotite 5%, muscovite below 1% and chlorite below 1%. polarized light microscope observations confirm two generations of potassium feldspar, the early phase being a feldspar within the potassium feldspar megacryst with cross-hatched extinction pattern (fig. 2b). this extinction pattern is characteristic for microcline twinning (fig. 2c), which is regarded as a result of orthoclaseto-microcline solid-state transformation (laves, 1950; mclaren, 1984). in the sample ppg-24, orthoclase grains can be distinguished besides plagioclase according to polarized light micro scopy (fig. 2e). this sample has the following modal composition: plagioclase 63%, orthoclase 16%, quartz 9%, biotite 10% and chlorite under 2%. besides lamellar plagioclase grains (fig. 2e), zoned plagioclase also occurs (fig. 2f). three pink megacrysts and whole rock of 2ppg-4 sample, and white feldspar from non-magnetic, low-density fraction of ppg-24 sample were analysed with xrpd. the reference diffraction data were: quartz (morris et al., 1981), intermediate microcline (borg & smith, 1969), orthoclase (borg & smith, 1969), albite, calcian (borg & smith, 1968), mica (grim et al., 1937) in brown (1961), albite (smith, 1956), orthoclase (prince et al., 1973), microcline (allan et al., 1997) and quartz (pakhomov et al., 1993). for the 2ppg-4 sample grains xrpd patterns showed orthoclase and microcline, minor quartz, albite and mica (table 1, fig. 3). the diffraction pattern of the whole rock 2ppg-4 sample yielded microcline, minor quartz, albite and mica (table 1). the triclinic symmetry of microcline manifests in the d131d reflection splitting into (131) and (13̄1) at the following d-values: 3.015(3.025) å and 2.980(2.996) å (fig. 3, table 1). the value of triclinicity (d = d(131) – d(1-31) * 12.5) is 0.44 (grain a) and 0.36 (grain c) calculated according to goldsmith & laves (1954). low albite peaks appear at the following figure 3. xrpd analysis magnified detail of {131} diffraction region: a) pink megacryst extracted from the granite sample 2ppg-4 (grain a, this study); b) pink megacryst extracted from the granite sample 2ppg-4 (grain b, this study); c) pink megacryst extracted from the granite sample 2ppg-4 (grain c, this study); d) non-magnetic, low-density fractions of whole rock ppg-24 sample (taken from horvat et al., 2011). the related data set is in table 1) im – intermediate microcline; o – orthoclase; a – albite; d values in ångströms. g eologia c roatica 49horvat et al.: microstructures of feldspar crystals from pakra creek valley granite (papuk mt., croatia) ta bl e 1. x rp d d at a se ts o f t hr ee p in k m eg ac ry st s a nd w ho le -r oc k of th e 2p pg -4 s am pl e an d no nm ag ne tic , l ow d en si ty fr ac tio ns o f w ho le ro ck p pg -2 4 sa m pl e. t he re fe re nc e di ffr ac tio n da ta fo r 2 pp g -4 g ra in s a a nd b , an d pp g -2 4 sa m pl e: q ua rt z (m o rr is e t a l., 1 98 1) , i nt er m ed ia te m ic ro cl in e (b o rg & s m it h , 1 96 9) , o rt ho cl as e (b o rg & s m it h , 1 96 9) , a lb ite , c al ci an (b o rg & s m it h , 1 96 8) , m ic a (g ri m e t a l., 1 93 7) in b ro w n (1 96 1) ; g ra in c an d w ho le ro ck o f 2 pp g -4 s am pl e: a lb ite (s m it h , 1 95 6) , a lb ite , c al ci an (b o rg & s m it h , 1 96 8) , o rt ho cl as e (p ri n ce e t a l., 1 97 3) , m ic ro cl in e (a ll a n e t a l., 1 99 7) , q ua rt z (p a kh o m o v et a l., 1 99 3) . l eg en d: d ob – o bs er ve d re fle ct io n, i l it – re fle ct io n in te ns ity (l ite ra tu re d at a) , s – s tr on g in te ns ity . d o b ( å ) 2p pg -4 a d o b (å ) 2p pg -4 b d o b ( å ) 2p pg -4 c d o b ( å ) 2p pg -4 d o b ( å ) pp g -2 4 i re la tiv e 2p pg -4 a i re la tiv e 2p pg -4 b i re la tiv e 2p pg -4 c i re la tiv e 2p pg -4 i re la tiv e pp g -2 4 m in er al d l it (å ) hk l i lit 10 .0 3 10 .0 3 10 .0 7 10 .0 9 10 .0 1 0. 6 1. 1 0. 8 4. 0 0. 8 m ic a 9. 99 00 2 s 6. 51 0 6. 51 0 6. 48 9 6. 49 8 6. 48 7 5. 5 5. 9 1. 8 0. 6 4. 3 in te rm ed ia te m ic ro cl in e/ or th oc la se / m ic ro cl in e 6. 48 3/ 6. 49 8/ 6. 48 2 00 1/ 02 0 6/ 7/ 7. 9 6. 39 6 6. 39 0 6. 41 2 0. 5 1. 2 0. 8 al bi te /a lb ite -c a 6. 39 0 00 1 20 5. 94 1 5. 91 0 5. 89 2 5. 87 7 5. 90 6 1. 2 1. 6 0. 5 0. 6 0. 8 in te rm ed ia te m ic ro cl in e/ or th oc la se / m ic ro cl in e/ al bi te /a lb ite -c a 5. 89 3/ 5. 86 1 1̄ 1̄ 1/ 1̄1 1 5/ 7 4. 61 3 4. 60 3 4. 59 2 4. 60 3 4. 59 4 1. 2 1. 3 0. 2 0. 3 0. 7 in te rm ed ia te m ic ro cl in e/ or th oc la se / m ic ro cl in e 4. 58 7/ 4. 58 3 02̄ 1/ 02 1 3/ 2 4. 23 4 4. 22 8 4. 22 8 4. 23 3 4. 23 0 8. 7 12 .7 2. 4 8. 3 7 in te rm ed ia te m ic ro cl in e/ or th oc la se / m ic ro cl in e 4. 25 7/ 4. 21 7 10 0/ 2̄0 1 22 /6 1 4. 04 5 4. 04 5 4. 03 7 4. 04 1 4. 04 2 2. 7 3. 1 1. 1 8. 7 5 al bi te /a lb ite -c a 4. 03 0 2̄0 1 16 /5 2 3. 97 0 3. 95 6 3. 95 6 3. 95 5 3. 95 1 5. 5 7. 7 1. 1 1. 6 3. 7 in te rm ed ia te m ic ro cl in e/ m ic ro cl in e 3. 96 1 11 1 11 /1 0 3. 87 0 3. 86 3 3. 86 0 3. 87 4 3. 86 6 2. 5 2. 6 0. 6 1. 7 2 al bi te /a lb ite -c a 3. 85 7 11̄ 1 8 3. 79 2 3. 78 5 3. 77 8 3. 77 1 3. 78 7 8. 6 15 2. 3 9. 5 9. 7 in te rm ed ia te m ic ro cl in e/ al bi te / or th oc la se /a lb ite -c a 3. 79 2/ 3. 78 0/ 3. 77 5 13 0/ 11 1/ 13 0 36 /2 5/ 75 3. 76 5 3. 67 9 3. 71 8 3. 71 8 7. 7 1. 3 0. 7 5. 8 in te rm ed ia te m ic ro cl in e/ al bi te / al bi te -c a 3. 74 6/ 3. 65 7 1̄3 0/ 20 0 37 /1 8 3. 67 7 3. 64 2 3. 66 6 3. 66 4 3. 66 5 2. 9 1. 3 0. 9 5. 1 3. 9 al bi te /a lb ite -c a 3. 66 3 1̄ 3̄1 16 3. 61 8 3. 63 9 3. 59 7 3. 59 8 1. 5 0. 7 0. 7 0. 7 in te rm ed ia te m ic ro cl in e/ or th oc la se / m ic ro cl in e 3. 62 9 1̄ 3̄1 12 3. 56 4 3. 54 1 3. 53 8 3. 57 5 0. 7 0. 4 0. 9 0. 6 or th oc la se /m ic ro cl in e 3. 56 3/ 3. 53 6 2̄2 1/ 2̄ 2̄1 9 3. 47 9 3. 48 3 3. 47 7 3. 47 5 3. 46 9 21 26 4. 5 6. 3 21 .7 in te rm ed ia te m ic ro cl in e/ or th oc la se / m ic ro cl in e 3. 47 7 1̄ 1̄2 46 3. 34 4 3. 34 1 3. 34 5 3. 34 7 3. 34 0 16 19 16 10 0 32 qu ar tz /in te rm ed ia te m ic ro cl in e/ m ic ro cl in e 3. 34 2/ 3. 33 5 10 1/ 22 0 53 3. 29 6 3. 32 6 3. 29 3 3. 29 5 3. 30 2 17 16 5 7. 3 14 in te rm ed ia te m ic ro cl in e/ or th oc la se / m ic ro cl in e 3. 29 3/ 3. 33 5 2̄2 0/ 22 0 50 /5 3 3. 24 4 3. 30 5/ 3. 24 4 3. 24 3 3. 24 3 3. 25 2 10 0/ 19 24 /1 00 10 0 25 .6 10 0 in te rm ed ia te m ic ro cl in e/ or th oc la se / m ic ro cl in e 3. 31 0/ 3. 24 2 22 0/ 00 2 10 0/ 97 3. 19 5 3. 19 8 3. 19 4 3. 20 8 3. 19 7 10 0 26 13 .4 18 .0 30 al bi te /a lb ite -c a 3. 19 6 00 2 10 0 g eo lo gi a c ro at ic a 50 geologia croatica 78/1 d o b ( å ) 2p pg -4 a d o b (å ) 2p pg -4 b d o b ( å ) 2p pg -4 c d o b ( å ) 2p pg -4 d o b ( å ) pp g -2 4 i re la tiv e 2p pg -4 a i re la tiv e 2p pg -4 b i re la tiv e 2p pg -4 c i re la tiv e 2p pg -4 i re la tiv e pp g -2 4 m in er al d l it (å ) hk l i lit 3. 01 5 3. 02 5 3. 00 5 6. 5 0. 4 7.1 in te rm ed ia te m ic ro cl in e 3. 00 5 13 1 26 2. 98 0 2. 99 8 2. 99 6 2. 99 7 2. 97 9 7.1 12 2 5. 3 5. 2 in te rm ed ia te m ic ro cl in e/ or th oc la se / al bi te -c a 2. 97 9/ 2. 99 1 13̄ 1/ 13 1 29 /5 4 2. 94 1 2. 94 1 2. 93 4 2. 93 8 2. 93 8 3. 5 3 1 5. 8 3. 8 al bi te /a lb ite -c a 2. 94 6 02̄ 2 5 2. 90 3 2. 90 3 2. 90 4 2. 90 3 2. 90 3 12 15 3 3. 7 7 in te rm ed ia te m ic ro cl in e/ m ic ro cl in e 2. 90 0 04 1 27 2. 86 5 2. 86 4 2. 85 2 2. 84 9 2. 85 6 1. 4 0. 6 0. 4 2. 3 1. 8 al bi te /a lb ite -c a 2. 86 6 13 1 8 2. 77 6 2. 77 4 2. 77 1 2. 77 1 2. 77 0 3. 9 5. 4 1 1. 6 2. 6 in te rm ed ia te m ic ro cl in e/ m ic ro cl in e 2. 77 4 1̄ 3̄2 11 2. 59 9 2. 58 9 2. 59 7 2. 61 2. 59 3 3. 9 4. 4 1 1. 6 2. 5 in te rm ed ia te m ic ro cl in e/ or th oc la se / m ic ro cl in e 2. 58 9 2. 59 3 2̄ 4̄1 /2 21 19 2. 56 3 2. 56 2 2. 55 7 2. 55 9 2. 55 6 7. 5 7. 8 1. 8 5. 0 2. 5 in te rm ed ia te m ic ro cl in e/ or th oc la se / m ic ro cl in e 2. 56 0 11 2 21 /1 0 2. 53 3 2. 52 9 2. 52 1 2. 52 0 2. 53 5 2 2. 5 0. 83 2. 2 3. 4 in te rm ed ia te m ic ro cl in e/ al bi te -c a 2. 52 8 31 0 5 2. 46 3 2. 45 7 2. 45 8 2. 46 1 0. 8 0. 96 6. 8 1. 4 qu ar tz 2. 45 7 11 0 8 2. 42 5 2. 42 3 2. 42 1 2. 43 4 2. 42 4 1. 5 1. 9 0. 35 1. 5 1. 4 in te rm ed ia te m ic ro cl in e/ al bi te -c a 2. 42 0 1̄5 1 5 2. 41 3 2. 40 8 2. 40 4 2. 40 8 1. 5 1. 9 0. 8 1. 3 al bi te -c a 2. 40 3 3̄3 1 7 2. 33 5 2. 33 3 2. 33 0 2. 33 0 2. 33 2 2. 8 3 0. 89 1. 5 1. 8 in te rm ed ia te m ic ro cl in e/ or th oc la se / al bi te -c a/ m ic ro cl in e 2. 33 0 1̄ 1̄3 6 2. 28 5 2. 28 4 2. 28 2 2. 28 2. 28 4 0. 8 0. 9 1. 28 8. 2 1. 1 qu ar tz 2. 28 2 10 2 8 2. 19 6 2. 19 0 2. 21 0 0. 7 0. 15 0. 5 al bi te -c a/ in te rm ed ia te m ic ro cl in e 2. 18 9 15̄ 1 3 2. 16 6 2. 16 5 2. 16 2 2. 16 4 2. 16 3 10 .8 9 5. 23 3. 8 6 in te rm ed ia te m ic ro cl in e/ or th oc la se / m ic ro cl in e 2. 16 0 06 0 17 2. 13 3 2. 12 7 2. 13 7 2. 13 6 2. 13 6 1. 8 2. 7 0. 77 2. 5 1. 5 al bi te -c a 2. 13 7 24 1 5 2. 11 9 2. 12 2 2. 12 9 2. 12 9 2. 11 7 1. 8 2. 7 1. 44 9. 5 2 qu ar tz /a lb ite /in te rm ed ia te m ic ro cl in e/ or th oc la se 2. 12 7/ 2. 11 4 20 0/ 2 4̄ 1 6/ 9 2. 08 0 2. 07 5 2. 07 4 2. 10 7 2. 07 4 1. 2 1. 7 0. 78 3. 0 1 in te rm ed ia te m ic ro cl in e/ o rt ho cl as e/ al bi te -c a 2. 07 4 1̄3 3 4 2. 06 1 2. 05 7 2. 05 2 2. 04 9 2. 05 3 1. 2 2 0. 46 0. 5 1 in te rm ed ia te m ic ro cl in e/ o rt ho cl as e/ m ic ro cl in e 2. 05 0 06 1 4 g eologia c roatica 51horvat et al.: microstructures of feldspar crystals from pakra creek valley granite (papuk mt., croatia) d-values: 4.04 å, 3.87(3.86) å, 3.64(3.68) å, 3.19 å, 2.93(2.94) å and 2.85(2.86) å (table 1). one pink grain was determined as orthoclase (grain b). these results, together with the tri clinicity values obtained and calculated in the previous study (horvat et al., 2011) indicate lower triclinicity values for potassium feldspars from porphyritic and high(er) tri cli nicity values for the potassium feldspars from homogeneous granite types (table 2). according to xrpd analysis, the white feldspar from ppg-24 sample proved to be mixture of intermediate microcline and plagioclase with a composition of ab=71%, an=29% (borg & smith, 1968) albite, ca-bearing, ordered (table 1). besides feldspar phases, minor mica and quartz were detected. triclinicity of the microcline component is 0.32 (table 2). by using tem methods, crystal chemical details averaged out by xrd can be studied, which potentially provides a more precise crystallization history of these feldspar crystals. during the tem eds study of the 2ppg-4 sample mostly crystals with or > 90% and an=0 composition were measured (for detailed measurement data see suppl. 1), besides that only one grain with albite composition or(1.2)ab(98.8)an(0), and low albite structure was found. figure 4 shows the characteristic microstructure of crystals with high potassium content. low magnification tem images of the feldspar megacrysts in the 2ppg-4 sample exhibit a tweed pattern (fig. 4a). on the [001] zone axis saed pattern (fig. 4a), diffuse scattering is observable along the two marked reciprocal axes, which makes a star-like shape of the diffraction spots (fig. 4c). such a distortion of diffraction spots indicates the simultaneous presence of albite and pericline twins (sanchez-munoz et al., 2012). the angle between [010]* and [100]* is 90°, which suggests monoclinic structure, however, careful observation of the diffraction spots at large scattering angles reveals that, while 90° is the dominant angle, the [010]* axis wobbles up to 0.7° in the studied volume (fig. 4b). in some cases, clear splitting of 0k0 spots can also be observed. an hrtem image shows the two orthogonal lattice distortions in more detail (fig. 4d). intensity variation was measured along the [010] and [100] lattice directions, and lattice periodicity was found to be constant up to 100 nm scale. undulations of intensity maxima were found on the 10 nm scale (figs. 4e, f) in both directions, table 2. list of triclinicity values (a=12.5*ad(131)-d(13̄1a) calculated according to goldsmith & laves (1954), for potassium feldspars from nonmagnetic, low density fractions of whole rock (homogeneous rock type) and megacrysts (porphyritic rock type) of granites from pakra creek valley (papuk mt., croatia). sample name rock type d calculated triclinicity 1 2ppg-4 (a) porphyritic 0.44 2 2ppg-4 (b)* porphyritic 0 3 2ppg-4 (c) porphyritic 0.36 4 ppg-24* homogeneous 0.32 5 2ppg-3* porphyritic 0 6 2ppg-5* porphyritic 0.29 7 2ppg-6 (a)* porphyritic 0 8 2ppg-6 (b)* porphyritic 0 9 ppg-19* homogeneous 0 10 ppg-18* homogeneous 0.87 11 ppg-20* homogeneous 0.70 12 ppg-23* homogeneous 0.56 *triclinicity values from horvat et al. (2011) figure 4. a) tem bright field image of a feldspar crystal of or(91.9)ab(8.1)an(0) composition exhibiting tweed pattern with its [001] zone axis saed pattern in the inset. indexing is according to orthoclase structure; b,c) enlarged diffraction spots showing their typical shapes; d) hrtem image of the same crystal; and e,f) intensity profiles along lines a and p in a 100 px wide band. profile a and p show banding related to albite and pericline twinning. g eo lo gi a c ro at ic a 52 geologia croatica 78/1 these correspond to the thickness of albite and pericline twin lamellae. (during this analysis, a uniform sample thickness was supposed, supported by the same range of intensity variation measured in the two perpendicular directions on fig. 4e, f). according to tem eds, the feldspar from the ppg-24 sample is a plagioclase with a na:ca ratio close to 3:1 and minor k content (72.2%<ab<76.5%, 23%<an<26.8%, or<1.4%), which is in agreement with xrd results (for detailed measurement data see suppl. 2). besides, two low albite grains (with ab 97 and 99%) and an anorthite grain (an=99%) were detected. the microstructure of a plagioclase grain is presented in figure 5. [1̄02̄] zone axis saed pattern is indexed according to low albite structure (fig. 5a), however, in case of low albite, the [020]*^[201̄]* calculated angle is 87.5° (fig. 5c), while the measured angle on the experimental saed pattern is 90°, which implies monoclinic symmetry. besides, a diffuse streaking between diffraction spots parallel to [2̄01]* axis is observed (fig. 5a), which implies a more complex, disordered microstructure. for a better understanding of the structural disorder, fft analysis of hrtem images has been performed (fig. 5b). according to fft analysis, the [020]*^[201̄]* angle exhibits certain variation as a function of location, it ranges between 86.1° and 90° (fig. 5d). additionally, at some locations, concentration of the diffuse scattering is observed on the ffts halfway between the spots parallel to the [2̄01]* axis (fig. 5b red dotted arrows). at these locations, reflections only appear if the unit cell is larger, i.e. the c-axis is doubled with respect to albite structure. based on these observations, we believe that the saed represents an average structure with orthogonal (monoclinic) axes and additionally, disorder along [2̄01]* axis. on the nano scale, at the same time, structural and/ or chemical ordering has been initiated, and triclinic domains with doubled c-axis developed. figure 5. a) saed pattern of a feldspar crystal of or(1.4)ab(72.2)an(26.4) composition (ppg-24 sample), indexed as [1̄02̄] zone axis orientation of low albite. in the inset, the bright field image of the crystal is given. white dotted arrows indicate diffuse scattering between diffraction spots parallel to [2̄01]* axis; b) hrtem image of the same crystal. the fft of the area indicated by a white circle is in the upper left insert. the red dotted arrows on the fft show that half way between the spots, the diffuse scattering is concentrated. intensity profile along the a-b band is shown in the upper right insert. red dotted arrows indicate the half way reflections; c) calculated [1̄02̄] saed pattern of low albite (s.g. c1̄, a=8.142å, b= 12.785 å, c= 7.159 å, a= 94.19°, a= 116.61°, a= 87.61°); and d) calculated saed pattern of a high ca containing plagioclase (s.g. i1̄, a= 8.188 å, b= 12. 116.04°å, c= 14.196 å, a= 93.37°, a= 116.04°, a= 90.87°). red dotted arrows on (d) indicate extra spots with respect to (c); e) experimental saed pattern on (a) with the simulation shown on (d). note a good agreement of distances and angles between simulation and saed. g eologia c roatica 53horvat et al.: microstructures of feldspar crystals from pakra creek valley granite (papuk mt., croatia) 4. discussion although the xrpd profiles of the feldspar samples from the studied granites are quite similar, and proved to be intermediate microcline and orthoclase, (in the case of 2ppg-4) mixed with albite (2ppg-24) or albite-ca (ppg-24), the studied feldspars show microstructural and microtextural heterogeneities under the polarized light microscope (development of twin lamellae and twin boundaries, compositional zonation), and a complex, disordered nanostructure. tem eds measurements of both samples are in agreement with expectations based on the xrpd results, and in the case of the ppg-24 sample, they allow the specified composition to be related to the nano structure features. the presence of orthoclase in the xrpd patterns of the 2ppg-4 sample indicates a minimum value for the crystallization temperature of approx. 530 c° (fig. 6). the studied grains that showed triclinicity in their xrpd patterns, based on the splitting of (131) and (13̄1) reflections, reveal deviation from the monoclinic structure. obtained values of triclinicity that reflect an ordered al-si distribution in the tetrahedral sites are small (δ = 0.44, and 0.36). however, besides triclinic symmetry, the hrtem revealed tweed nanostructure. tweed structure forms by the simultaneous development of two independent twin systems, albite and pericline, as indicated by saed patterns and hrtem images (xu et al., 2000). this allows the relaxation of structural strain, which arises from the al-si ordering with cooling. the presence of tweed structure provides a lower limit of feldspar crystallization for deduced temperature of approximately 460 c° (griffen, 1992). based on tem eds, the ppg-24 sample contains several feldspar phases, albite anorthite and na-ca plagioclase (ab:an ≈ 3:1), the latter being the most frequently measured (for detailed measurement data see suppl. 2). this composition is in agreement with the composition of the plagioclase phase ab=71%, an=29% (borg & smith, 1968), which was identified on the xrpd pattern, besides the intermediate microcline. based on the hrtem study, the plagioclase composition can be related to nanostructure characteristics, which help the understanding of crystal formation. diffuse streaking and intensity concentration parallel to [2̄01]* of na-ca plagioclase indicates a complex, disordered nanostructure and an incipient structural and/or chemical ordering in a unit cell with c≈14å (fig. 5e). ordering cannot be completed because of kinetic reasons, but the triclinic structure is evident on hrtems (fig. 5b). according to the phase diagram (fig. 7), at the ab:an = 3:1 ratio measured in the ppg-24 sample, the plagioclase solid solution disproportionated to low albite and i1̄ anorthite at 400 c°. the i1̄ structure is consistent with the fft shown on figure 5b. the fact that no incommensurate structures have been found, suggests that the average composition of the starting material was close to the eutectic. regarding the temperature of crystallization, we can only estimate the lowest value as 400 c°, but not the possible highest temperature at which granite crystallization started. the zonation observed under polarized light is probably related to changing com position, as supported by the different ab:an ratios measured by tem eds. the “chemically” delayed kinetics of ordering are comparable to a relatively fast cooling rate, for instance in epizonal granitoids in an anorogenic or post-tectonic environment, where the emplacement of magma in a relatively cool environment produces rocks mostly consisting of xrpd proved orthoclase (marfunin, 1966; marmo, 1971). it is in connection with the temperature decrease, when the triclinic–monoclinic transition occurs (mckenzie, 2018). vernon (1986, 1990, 1999, 2004) and vernon & paterson (2002) reviewed the subject of the potassium feldspar megacrysts in granite, with the conclusion that the phenocrysts evidence is favoured. the same authors suggested figure 6. estimated average composition of the starting material (arrow) and chemical composition of a feldspar megacryst (asterisks) from 2ppg-4 sample plotted on the phase diagram of alkali feldspars (after smith, 1974; modified by brown, 1981; in griffen, 1992). g eo lo gi a c ro at ic a 54 geologia croatica 78/1 that k-feldspar megacrysts in granites grow late in the cooling history, even at subsolidus conditions. the experimental evidence indicates that potassium feldspar is one of the last minerals to become saturated in felsic magmas (piwinskii, 1968; piwinskii & wyllie, 1968; whitney, 1975; clemens & wall, 1981). however, experiments also indicate that when potassium feldspar begins to crystallize, the magma typically contains 60–70% liquid (clemens & wall, 1981; winkler & schultes, 1982). though potassium feldspar is commonly the last mineral to begin crystallizing in granitic magmas, abundant melt is still present at that stage, allowing sufficient space for the megacrysts to grow according to vernon (2004, and references therein). myrmekite develops at around 450-500 ?c (tribe & d’lemos, 1996) and 500–670 °c (wirt & voll, 1987), and relatively calcic plagioclase (oligoclase) in myrmekite, replaces potassium feldspar (vernon et al., 1983) implying relatively high temperatures. the minimum temperature estimated for crystal growth is 653–439 °c for two-mica granite as given by liu et al. (2023). the modal composition of the two granite samples corresponds to a monzogranite–granodiorite composition according to iugs (1973). the homogeneous structure and high plagioclase content of the sample ppg-24 most probably corresponds to higher crystallization temperatures compared to the porphyritic sample 2ppg-4, while the microstructure of the feldspars suggests parent melt close to eutectic composition for studied granites. 5. conclusion the feldspars from two different granite varieties from pakra creek valley (papuk mt.), one with a porphyritic texture and one with a homogeneous structure, were studied by optical pola rizing microscopy, x-ray powder diffraction and trans mission electron microscopy with energy-dispersive spectroscopy. the obtained results enable the following conclusions: 1) the porphyritic granite variety has a monzogranite com position and contains pink potassium feldspar megacrysts. pink potassium feldspars are revealed to be orthoclase and intermediate microcline (or > 90% and an=0). the tweed-like nanostructure provides evidence for the lower limit of potassium feldspar crystallization temperature of approximately 460 c°. 2) the homogeneous granite variety has a granodiorite composition and medium granular texture. it is abundant in plagioclase. it contains several feldspar phases: albite (or0.3ab98.7an1), anorthite (or0ab0.5an99.5) and na-ca plagioclase (or0.8ab74.1an25.1). under the polarizing microscope the observed potassium feldspar is orthoclase, showed as intermediate microcline in xrpd pattern, beside albite. the diffuse streaking and intensity concentration parallel to [2̄ 01]* of na-ca plagioclase indicates structural modulations. 3) the microstructure of the feldspars suggests a parent melt close to a eutectic composition for the studied granites. figure 7. estimated average composition of the starting material (arrow) and chemical composition of feldspars (asterisks) from ppg-24 sample plotted on the phase diagram of plagioclase (after carpenter & mcconnell, 1984). abbreviations: pe – peristerite intergrowth, bø – bøgglid intergrowth, hü – hüttenlocher intergrowth, ss – solid solution. structure types: e, c1̄, i1̄, p1̄. g eologia c roatica 55horvat et al.: microstructures of feldspar crystals from pakra creek valley granite (papuk mt., croatia) acknowledgment the presented work is the first result in the mineralogical frame of the internal research project “complementary petro chronological characterization of granites, progressively metamorphic rocks and migmatites in the papuk metamorphic complex (slavo nian mts., croatia) (papukron)” at croatian geological survey, funded by national recovery and resilience plan 2021–2026 of the european union – nextgenerationeu, and monitored by the ministry of science, education and youth of the republic of croatia. the authors extend their gratitude to the department of geology, croatian geological survey’s colleagues who helped in any way during the preparation of this work. the authors acknowledge the remarks and suggestions of the reviewers and associate editor, which greatly contributed to the quality of the manuscript. references allan, d.r. & angel, r.j. (1997): a high-pressure structural study of microcline (kalsi3o8) to 7 gpa.– european journal of mineralogy, 9/2, 263–275. http://doi.org/10.1127/ejm/9/2/0263 bambauer, u.h., krause, c. & kroll, h. (1989): tem-investigation of the sanidine/microcline transition across metamorphic zones: the k-feldspar varieties.– european journal of mineralogy, 1, 47–58. http:// doi.org/10.1127/ejm/01/1/0047 barth, t.f.w. (1934): polymorphism phenomena and crystal structure.– american journal of science, 227, 273–286. bateman, p.c. (1992): plutonism in the central part of the sierra nevada batholith, california.– u.s. geological survey professional paper 1483. https://doi.org/10.3133/pp1483 borg, i.y. & smith, d.k. (1968): calculated powder patterns. i. five plagioclases.– the american mineralogist, 53, 1709. borg, i.y. & smith, d.k. (1969): calculated x-ray powder patterns for silicate minerals.– geological society of america, inc. memoir, 122, 896 p. http://doi.org/10.1130/mem122-p1 brown, g. (1961): the x-ray identification and crystal structures of clay minerals.− mineralogical society, london, 544 p. brown, g. (1981): the bond valence method: an empirical approach to chemical structure and bonding.– in: o‘keefe, m. & navrotsky, a. (eds.): structure and bonding in crystals, vol. 2. academic press, new york, 357 p. http://doi.org/10.1016/b978-0-12-525102-0.50007-4 brown, w.l. & parsons, i. (1989): alkali feldspars: ordering rates, phase transformations and behaviour diagrams for igneous rocks.– mineralogical magazine, 53/369, 25–42. https://doi.org/10.1180/minmag. 1989.053.369.03 carpenter, m.a. & mcconnell, j.d.c. (1984): experimental delineation of the c1̄ and i1̄ transormation in intermediate plagioclase feldspars.– american mineralogists, 69, 112–121. clemens, j.d. & wall, v.j. (1981): origin and crystallization of some peraluminous (s-type) granitic magmas.– the canadian mineralogist, 9, 111–131. coleman, d.s., bartley, j.m., glazner, a.f. & law, r.d. (2005): incremental assembly and emplacement of mesozoic plutons in the sierra nevada and white and inyo ranges, california.– in: geological society of america field forum field trip guide (rethinking the assembly and evolution of plutons: field tests and perspectives, 7–14 october, 2005). https://doi.org/10.1130/2005.mcbfyt.ffg collins, l.g. & collins, b.j. (2002): k-metasomatism and the origin of baand inclusionzoned orthoclase megacrysts in the papoose flat pluton, inyo mountains, california, usa.– myrmekite and metasomatic granite, 44, 1–70. cox, r.a., dempster, t.j., bell, b.r. & rogers, g. (1996): crystallization of the shap granite: evidence from zoned k-feldspar megacrysts.– journal of the geological society of london, 153, 625–635. http://doi. org/10.1144/gsjgs.153.4.0625 dickson, f.w. & sabine, c.p. (1967): barium-zoned large k-feldspars in quartz monzonites of eastern and southeastern california.– geological society of america special paper, 115, 323 p. glazner, a. & johnson, b.r. (2013): late crystallization of k-feldspar and the paradox of megacrystic granites.– contributions to mineralogy and petrology, 166/3, https://doi.org/10.1007/s00410-013-0914-1 glazner, a.f., bartley, j.m., coleman, d.s., gray, w. & taylor, r.z. (2004): are plutons assembled over millions of years by amalgamation from small magma chambers?– gsa today, 14/4–5. https://doi.org/10.1130/1052-5173(2004)014%3c0004:apaomo%3e2.0. co;2 goldsmith, j.r. & laves, f. (1954): the microcline-sanidine stability relations.– geochimica cosmochimica acta, 5, 1–19. http://doi.org/ 10.1016/0016-7037(54)90058-7 griffen, d.t. (1992): silicate crystal chemistry.– oxford university press, oxford, 442 p. grim, r.e., bray, r.h. & bradley, r.f. (1937): mica in argillaceous sediments.− am. mineral., 22, 813–829. horvat, m. (2004): geochemistry and petrology of granitoids of papuk and psunj mts. (slavonia, croatia).– unpubl. phd thesis, university of budapest, budapest, hungary (133+108) p. horvat, m., tibljaš, d., buda, gy. & lovas, gy. (2011): x-ray study of potassium feldspars from different granitoid types and gneisses of papuk mt. (slavonia, croatia).– geologia croatica, 64/2, 153–162. https:// doi.org/104154/gc.2011.13 hovmöller, s (1992): crisp: crystallographic image processing on a personal computer.– ultramicroscopy, 41, 121–135. https://doi.org/10.1016/ 0304-3991(92)90102-p iugs subcommission on the systematics of igneous rocks (1973): classification and nomenclature of plutonic rocks. recommendations.– neues jahrbuch fur mineralogie abhandlungen, h 4, 149–164. jamičić, d. (2001): main geological features of the slavonian mts. focused to the našice area.– matica hrvatska, našički zbornik, 6, 29–36. johnson, b.r., glazner, a.f. & coleman, d.s. (2006a): significance of k-feldspar megacryst size and distribution the tuolumne intrusive suite, california.– geological society of america, abstracts with programs, 38, 93. johnson, b.r., glazner, a.f. & coleman, d.s. (2006b): potassium feldspar megacrysts in granites: passive markers of magma dynamics or products of textural coarsening?– eos transactions of the american geophysical union, 87/52, v51b–1670. kerrick, d.m. (1969): k-feldspar megacrysts from a porphyritic quartz monzonite, central sierra nevada, california.– the american mineralogist, 54, 839–848. kontonikas-charos, a., ciobanu, c.l., cook, n.j., ehrig, k., rismail†, r., krneta, s. & basak, a. (2018): feldspar mineralogy and rare-earth element (re)mobilization in iron-oxide copper gold systems from south australia: a nanoscale study.– mineralogical magazine, 82/s1, s173–s197. http://doi.org/10.1180/minmag.2017.081.040 kovács kis, v., horvat, m. & dódony, i. (2004): microstructures in two alkali feldspar megacrysts from the papuk mt., croatia.– geologia croatica, 57/2, 149–158. https://doi.org/10.4154/gc.2004.12 kučan, f. & krmpotić, m. (1911): microclinemicroperthite from pakra [in croatian].– glasnik hrvatskog prirodoslovnog društva. godište xxiii, zagreb, 104–107. laves, f. (1950): the lattice and twinning of microcline and other potash feldspar.– journal of geology, 58, 548–571. laves, f. & goldsmith, j.r. (1961): polymorphism, order, disorder, diffusion and confusion in the feldspars.– estudos geologicos, cursillos y conferencias, 8, 71–80. liu, y., qin, k., zhao, j., zhou, q., shi, r., he, c. & gao, y. (2023): feldspar traces mineralization processes in the qongjiagang giant lithihttps://www.sciencedirect.com/journal/ultramicroscopy g eo lo gi a c ro at ic a 56 geologia croatica 78/1 um ore district, himalaya, tibet.– ore geology reviews, 157/105451. https://doi.org/10.1016/j.oregeorev.2023.10545 marfunin, a.s. (1966): the feldspars. phase relations, optical properties, and geological distribution.– israel program for scientific translations, jerusalem, israel. marmo, v. (1971): granite petrology and the granite problem.– elsevier, new york. mckenzie, w.s. (2018): the orthoclase-microcline inversion.– mineralogical magazine and journal of the mineralogical society, 30/225, 354–366. https://doi.org/10.1180/minmag.1954.030.225.03 mclaren, a.c. (1984): transmission electron microscope investigations of the microstructures of microclines.– in: brown, w.l. (ed.): feldspars and feldspathoids. nato asi series, ser c. 137, 373–409. http://doi. org/10.1007/978-94-015-6929-3_10 morris, m.c., mcmurdie, h.f., evans, e.h., paretzkin, b., parker, h.s. & panagiotopoulos, n.c. (1981): standard x-ray diffraction powder patterns section 18 – data for 58 substances. silicon oxide (quartz, low), a-sio2.– national bureau of standards monograph, 25, 61 p. navrotsky, a. (2011): nanoscale effects on thermodynamics and phase equilibria in oxide systems.– chemphyschem, 12, 2207–2215. http://doi. org/10.1002/cphc.201100129 navrotsky, a., mazeina, l. & majzlan, j. (2008): size-driven structural and thermodynamic complexity in iron oxides.– science, 319, 1635–1638. http://doi.org/10.1126/science.1148614 pakhomov, v.i., goryunov, a.v., pakhomov, p.v. & chibiskova, n.t. (1993): on the structure of alpha-sio2 crystals doped with fe3+.– zhurnal neorganicheskoi khimii, 38, 39–44. panalytical (2016): x’pert software highscore plus, version 4.5 (4.5.0.22741), almeo, the netherlands. parsons, i., gerald, j.d.f. & lee, m.r. (2015): routine characterization and interpretation of complex alkali feldspar intergrowths.– american mineralogist, 100/5–6, 1277–1303. http://doi.org/10.2138/am-20155094 piwinskii, a.j. (1968): experimental studies of igneous rock series, central sierra nevada batholith, california.– journal of geology, 76, 548–570. http://doi.org/10.1086/627359 piwinskii, a.j. & wyllie, p.j. (1968): experimental studies of igneous rock series: a zoned pluton in the wallowa batholith, oregon.– journal of geology, 76, 205–234. http://doi.org/10.1086/627323 poljak, j. (1952): predpaleozojske i paleozojske naslage papuka i krndije [paleozoic and before paleozoic deposits of papuk and krndija – in croatian].– geološki vjesnik, 2-4, 63–82. prince, e., donnay, g. & marth, r.f. (1973): neutron diffraction refinement of an ordered orthoclase structure.– american mineralogist, 58/5–6, 500–507. ribbe, p.h. (ed.) (1983): feldspar mineralogy.– reviews in mineralogy, mineralogical society of america, chantilly, virginia. rockhold, j.r., nabelek, p.i. & glascock, m.d. (1987): origin of rhythmic layering in the calamity peak satellite pluton of the harney peak granite, south dakota: the role of boron.– geochim cosmochim acta, 51, 487–496. http://doi.org/10.1016/0016-7037(87)90063-9 sánchez-muñoz, l., garcía-guinea, j., zagorsky, v.ye., juwono, t., modreski, p.j., cremades, a., van tendeloo, g. & de moura, o.j.m. (2012): the evolution of twin patterns in perthitic k-feldspar from granitic pegmatites.– the canadian mineralogist, 50, 989–1024. https://doi.org/10.3749/canmin.50.4.989 schmid, s.m., fügenschuh, b., kounov, a., matenco, l., nievergelt, p., oberhänsli, r., pleuger, j., schefer, s., schuster, r., tomljenović, b., ustaszewski, k. & van hinsbergen, d.j.j. (2020): tectonic units of the alpine collision zone between eastern alps and western turkey.– gondwana research, 78, 308–374. https://doi.org/10.1016/j.gr.2019.07.005 smith, j.v. (1956): geology and mineralogy. structural control of polymorphism in micas.– nature, 4656, p. 253. smith, j.v. (1974): feldspar minerals. i. crystal structure and physical properties.– springer-verlag, heidelberg, 627 p. stewart, d.b. & ribbe, p.h. (1983): optical properties of feldspars.– in: ribbe, p.h. (ed.): feldspar mineralogy, reviews in mineralogy and geochemistry, 2, 121–139. https://doi.org/10.1515/9781501508547-010 tajder, m. (1957): petrographic investigation of the western part of the papuk mt [in croatian].– ljetopis jazu, 62, 316–323. tribe, i.r. & d’lemos, r.s. (1996): significance of a hiatus in down-temperature fabric development within syn-tectonic quartz diorite complexes, channel islands, uk.– journal of the geological society of london, 153, 127–138. http://doi.org/10.1144/gsjgs.153.1.0127 vernon, r.h. (1986): k-feldspar megacrysts in granites – phenocrysts, not porphyroblasts.– earth-science reviews, 23/1, 1–63. https://doi. org/10.1016/0012-8252(86)90003-6 vernon, r.h. (1990): k-feldspar augen in felsic gneisses and mylonites– deformed phenocrysts or porphyroblasts?– geologiska föreningens i stockholm förhandlingar, 112, 157–167. http://doi.org/10.1080/ 11035899009453175 vernon, r.h. (1999): quartz and feldspar microstructures in metamorphic rocks.– canadian mineralogist, 37, 513–524. vernon, r.h. (2004): a practical guide to rock microstructure.– cambridge university press, cambridge, 594 p. http://doi.org/10.1017/ cbo9780511807206 vernon, r.h. & paterson, s.r. (2002): igneous origin of k-feldspar megacrysts in deformed granites of the papoose flat pluton, california, usa.– electronic geosciences, 7, 31–39. http://doi.org/10.1007/s10069002-0005-3 vernon, r.h., williams, v.a. & d’arcy, w.f. (1983): grainsize reduction and foliation development in deformed granitoid batholith.– tectonophysics, 92, 123–145. vragović, m. (1965): granites and gneisses of the papuk mountain [in croatian].– unpubl. phd thesis. sveučilište u zagrebu, prirodoslovno-matematički fakultet, zagreb, 1-xy p. warr, l.n. (2021): ima-cnmnc approved mineral symbols.– mineralogical magazine, 85, 291–320. https://doi.org:10.1180/mgm.2021.43 webber, k.l., simmons, w.b., falster, a.u. & foord, e.e. (1999): cooling rates and crystallization dynamics of shallow level pegmatite-aplite dikes, san diego county, california.– american mineralogist, 84, 708–717. http://dx.doi.org/10.2138/am-1999-5-602 whitney, j.a. (1975): the effects of pressure, temperature, and xh2o on phase assemblages in four synthetic rock compositions.– journal of geology, 83, 1–31. willaime, c., brown, w.l. & gandais, g. (1976): physical aspects of exolution in natural alkali feldspars.– in: wenk, h.r. (ed.): electron microscopy in mineralogy. springer-verlag, berlin, 248–257. winkler, h.g.f. & schultes, h. (1982): on the problem of alkali feldspar phenocrysts in granitic rocks.– neues jahrbuch für mineralogie monatshefte, 12, 558–564. wirt, r. & voll, g. (1987): cellular intergrowth between quartz and sodium-rich plagioclase (myrmekite) – an analogue of discontinuous precipitation in metal alloys.– journal of materials science, 22, 1913–1918. http://dx.doi.org/10.1007/bf01132916 xu, h., veblen, d.r., buseck, p. & ramakrishna, b.l. (2000): tem and sfm of exsolution and twinning in an alkali feldspar.– american mineralogist, 85, 509–514. http://doi.org/10.2138/am-20000412 g eologia c roatica 57horvat et al.: microstructures of feldspar crystals from pakra creek valley granite (papuk mt., croatia) supplement 1. – tem eds measurements of grains from sample 2ppg-4. 2ppg-4 sample, pink grain 2024/08/01 analysis number 0928 – or(1.2)ab(98.8)an(0) z element family atomic fraction (%) atomic error (%) mass fraction (%) mass error (%) fit error (%) 8 o k 61.45 3.06 48.65 3.31 0.38 11 na k 7.34 1.41 8.35 1.63 1.66 13 al k 7.63 1.44 10.19 1.93 0.96 14 si k 23.49 3.49 32.65 4.31 0.68 19 k k 0.09 0.02 0.17 0.03 2.54 2ppg-4 sample, pink grain 2024/08/01 analysis number 1030 – or(91.8)ab(8.2)an(0) z element family atomic fraction (%) atomic error (%) mass fraction (%) mass error (%) fit error (%) 8 o k 60.69 6.70 45.40 3.21 2.11 11 na k 0.63 0.14 0.67 0.14 1.03 13 al k 8.34 1.88 10.52 2.20 1.76 14 si k 23.41 5.18 30.74 6.29 1.58 19 k k 6.93 1.43 12.67 2.39 0.40 20 ca k 0.00 0.00 0.00 0.00 0.00 2ppg-4 sample, pink grain 2024/08/01 analysis number 1045 – or(89.5)ab(10.5)an(0) z element family atomic fraction (%) atomic error (%) mass fraction (%) mass error (%) fit error (%) 8 o k 60.78 6.90 45.83 3.32 2.03 11 na k 0.65 0.15 0.70 0.15 1.11 13 al k 8.30 1.89 10.56 2.22 1.51 14 si k 24.77 5.52 32.78 6.72 1.33 19 k k 5.50 1.15 10.13 1.92 0.34 20 ca k 0.00 0.00 0.00 0.00 0.00 2ppg-4 sample, pink grain 2024/08/01 analysis number 1047 – or(93.3)ab(6.7)an(0) z element family atomic fraction (%) atomic error (%) mass fraction (%) mass error (%) fit error (%) 8 o k 61.66 2.98 46.31 3.03 0.38 11 na k 0.51 0.11 0.55 0.12 5.92 13 al k 7.90 1.49 10.01 1.90 2.29 14 si k 22.87 3.42 30.16 4.15 1.04 19 k k 7.07 1.20 12.97 2.14 0.16 20 ca k 0.00 0.00 0.00 0.00 515.82 2ppg-4 sample, pink grain 2024/08/01 analysis number 1136 – or(86.6)ab(13.4)an(0) z element family atomic fraction (%) atomic error (%) mass fraction (%) mass error (%) fit error (%) 8 o k 61.00 3.02 45.84 3.05 0.74 11 na k 1.00 0.20 1.08 0.23 1.14 13 al k 7.95 1.49 10.07 1.90 1.27 14 si k 23.54 3.50 31.05 4.22 1.35 19 k k 6.51 1.12 11.95 2.00 0.07 20 ca k 0.00 0.00 0.01 0.00 19.49 2ppg-4 sample, pink grain 2024/09/24 analysis number 1259 – or(91.9)ab(8.1)an(0) z element family atomic fraction (%) atomic error (%) mass fraction (%) mass error (%) fit error (%) 8 o k 61.42 6.56 46.18 3.13 1.58 11 na k 0.59 0.13 0.64 0.13 2.18 13 al k 8.43 1.89 10.69 2.23 0.93 14 si k 22.83 5.02 30.13 6.14 1.11 19 k k 6.73 1.38 12.36 2.32 0.41 20 ca k 0.00 0.00 0.00 0.01 0.00 g eo lo gi a c ro at ic a 58 geologia croatica 78/1 2ppg-4 sample, pink grain 2024/09/24 analysis number 1231 – or(94.8)ab(5.2)an(0) z element family atomic fraction (%) atomic error (%) mass fraction (%) mass error (%) fit error (%) 8 o k 60.09 6.72 44.97 3.14 0.42 11 na k 0.33 0.08 0.36 0.07 1.33 13 al k 8.41 1.91 10.61 2.22 0.96 14 si k 25.09 5.59 32.96 6.76 1.20 19 k k 6.07 1.27 11.11 2.10 0.58 20 ca k 0.00 0.00 0.00 0.00 0.00 2ppg-4 sample, pink grain 2024/09/24 analysis number 1135 – or(91.1)ab(8.9)an(0) z element family atomic fraction (%) atomic error (%) mass fraction (%) mass error (%) fit error (%) 8 o k 61.64 2.99 46.47 3.04 0.85 11 na k 0.62 0.13 0.68 0.14 0.75 13 al k 8.41 1.57 10.69 2.00 1.15 14 si k 22.88 3.42 30.28 4.16 0.74 19 k k 6.45 1.10 11.88 1.98 0.35 20 ca k 0.00 0.00 0.00 0.00 0.00 g eologia c roatica 59horvat et al.: microstructures of feldspar crystals from pakra creek valley granite (papuk mt., croatia) supplement 2. – tem eds measurements of grains from sample ppg-24. ppg-24 sample, white grain 2024/08/01 analysis number 1316 – or(0.5)ab(76.5)an(23) z element family atomic fraction (%) atomic error (%) mass fraction (%) mass error (%) fit error (%) 8 o k 61.08 2.80 47.67 2.94 0.59 11 na k 6.63 1.28 7.44 1.45 1.88 13 al k 9.85 1.80 12.96 2.35 1.43 14 si k 20.40 3.16 27.94 3.96 0.95 19 k k 0.05 0.01 0.09 0.02 5.31 20 ca k 1.99 0.28 3.90 0.55 0.28 ppg-24 sample, white grain 2024/08/01 analysis number 1322 – or(0)ab(0.7)an(99.3) z element family atomic fraction (%) atomic error (%) mass fraction (%) mass error (%) fit error (%) 8 o k 56.85 2.68 40.80 2.49 0.63 11 na k 0.08 0.02 0.08 0.02 7.85 13 al k 16.88 2.83 20.44 3.35 1.26 14 si k 15.61 2.59 19.67 3.18 0.33 19 k k 0.00 0.00 0.00 0.00 0.00 20 ca k 10.57 1.34 19.01 2.30 0.22 ppg-24 sample, white grain 2024/08/01 analysis number 1412 – or(1.4)ab(72.2)an(26.4) z element family atomic fraction (%) atomic error (%) mass fraction (%) mass error (%) fit error (%) 8 o k 57.37 3.00 43.71 3.01 1.27 11 na k 5.66 1.11 6.20 1.24 1.11 13 al k 10.98 2.00 14.11 2.55 0.67 14 si k 23.80 3.54 31.82 4.29 0.45 19 k k 0.11 0.02 0.21 0.04 1.37 20 ca k 2.07 0.29 3.95 0.57 0.39 ppg-24 sample, white grain 2024/09/24 analysis number 1355 – or(0.6)ab(99.4)an(0) z element family atomic fraction (%) atomic error (%) mass fraction (%) mass error (%) fit error (%) 8 o k 62.80 2.97 50.10 3.26 0.60 11 na k 7.28 1.39 8.34 1.62 0.90 13 al k 7.71 1.45 10.37 1.95 1.22 14 si k 22.06 3.33 30.90 4.18 0.24 19 k k 0.04 0.01 0.08 0.01 2.73 ppg-24 sample, white grain 2024/09/24 analysis number 1409 – or(0.3)ab(97.5)an(2.3) z element family atomic fraction (%) atomic error (%) mass fraction (%) mass error (%) fit error (%) 8 o k 61.46 6.62 48.60 3.28 0.09 11 na k 7.01 1.58 7.96 1.67 0.59 13 al k 8.08 1.82 10.77 2.25 0.07 14 si k 23.27 5.13 32.30 6.59 0.06 19 k k 0.02 0.00 0.03 0.01 7.48 20 ca k 0.17 0.03 0.33 0.05 0.90 ppg-24 sample, white grain 2024/09/24 analysis number 1427 – or(0)ab(0.3)an(99.7) z element family atomic fraction (%) atomic error (%) mass fraction (%) mass error (%) fit error (%) 8 o k 57.79 2.77 41.82 2.62 2.91 11 na k 0.03 0.01 0.03 0.01 10.30 13 al k 16.18 2.75 19.75 3.28 1.51 14 si k 16.08 2.66 20.42 3.27 0.26 19 k k 0.00 0.00 0.00 0.00 0.00 20 ca k 9.92 1.28 17.99 2.21 0.09 g eo lo gi a c ro at ic a 60 geologia croatica 78/1 ppg-24 sample, white grain 2024/10/09 analysis number 1030 – or(0.2)ab(76.5)an(23.3) z element family atomic fraction (%) atomic error (%) mass fraction (%) mass error (%) fit error (%) 8 o k 62.41 6.36 49.34 3.20 1.53 11 na k 6.47 1.44 7.35 1.53 0.22 13 al k 9.19 2.04 12.25 2.54 0.35 14 si k 20.87 4.53 28.96 5.87 0.14 19 k k 0.01 0.00 0.03 0.01 7.70 20 ca k 1.05 0.18 2.08 0.31 0.11 ppg-24 sample, white grain 2024/10/09 analysis number 1103 – or(0.8)ab(72.4)an(26.8) z element family atomic fraction (%) atomic error (%) mass fraction (%) mass error (%) fit error (%) 8 o k 61.27 6.16 47.73 3.02 0.86 11 na k 5.41 1.21 6.06 1.26 2.06 13 al k 10.44 2.31 13.72 2.84 0.68 14 si k 20.81 4.52 28.46 5.76 0.17 19 k k 0.07 0.01 0.12 0.02 2.57 20 ca k 2.00 0.33 3.91 0.57 0.32 ppg-24 sample, white grain 2024/10/09 analysis number 1140 – or(0.9)ab(73)an(26.1) z element family atomic fraction (%) atomic error (%) mass fraction (%) mass error (%) fit error (%) 8 o k 59.78 3.08 46.18 3.19 2.60 11 na k 4.42 0.88 4.91 0.99 0.27 13 al k 11.00 2.01 14.33 2.59 1.32 14 si k 23.15 3.48 31.40 4.27 0.95 19 k k 0.06 0.01 0.11 0.02 4.95 20 ca k 1.58 0.22 3.06 0.45 0.17 2022 | 75/special issue | 335–348 | 12 figs. | 1 tab. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the importance of ensuring reliable and unobstructed access to minerals in the future has been recognized by the european un­ ion, in considering the current needs and future development of european industry, as well as retaining high employment levels. the european commission’s commitment in this area is reflected in the adoption of the raw materials initiative (2008) which aims to ensure: a fair and sustainable supply of mineral raw ma­ terials from global markets; a sustainable and increasingly effi­ cient supply of mineral raw materials within the eu, leading to more rational use of resources through the supply of recycled secondary raw materials. the strategy includes all mineral raw materials which are used in european industry, excluding mate­ rials from agricultural production, as well as materials used as fuels (energy raw materials). the european commission regularly publishes a list of criti­ cal raw materials (crm) in the european union. the latest published crm list contains 30 different mineral raw materials (ec, 2020). some commodities, such as: bauxite, barite, tita­ nium, rare earth elements (light and heavy), vanadium, scandium and gallium are found either in primary mineral deposits in mon­ tenegro and/or within secondary resources, which are referred to (in national classification nomenclature) as technogenic mine­ the primary and secondary mineral resources of montenegro and their mapping into the european data model slobodan radusinović1,*, robert šajn2, božica jovanović1, duška rokavec2, katarina hribernik2, vasilije abramović1, matej draksler2, ivan danilović1 and mia jovanović1 1 geological survey of montenegro, kruševac bb, 81000 podgorica, montenegro (*corresponding author: radusinovic.s@geozavod.co.me) 2 geological survey of slovenia, dimičeva ulica 14, 1000 ljubljana, slovenia doi: 10.4154/gc.2022.20 abstract primary and secondary mineral resources are of strategic importance to the eu economy. montenegro, as a country candidate for membership in the eu, is required to follow (and later to implement) european policies, strategies as well as initiatives, including those related to mineral resources and the mining sector. the importance of providing access to mineral raw materials in the future is recognized by the eu, as well as meeting the needs of european industry, maintaining employment and ensuring further development. considering the overall economic situation in montenegro, it is important to encourge the mining sector and other industries based on the use of mineral resources in making a greater contribution to the development and sustainability of society as a whole and also increase the share of national gdp. the potential for discovery and utilization of primary and secondary mineral resources in montenegro is demonstrated. the most important metallic mineral resources are bauxite, lead and zinc, while conventional energy resources include coal (oil and gas potential has yet to be proven). in addition, there are abundant non-metallic mineral raw materials industrial minerals and construction materials. secondary mineral resources, especially aluminous red mud (bauxite residue), are also significant and have been the subject of research in recent years. tailings from flotation processes at operating and abandoned lead and zinc mines might also be of interest for metal recovery. bottom and flay ash from thermal power plants, slag from steel production, as well as marlstone and limestone from the hanging wall of coal deposits may also have potential. waste rocks could be used particularly for secondary aggregate production. a database was developed and the most important deposits of primary and secondary mineral resources in montenegro were mapped during the reseerve project. mineral data were harmonised so as to be inspire compliant. in addition, some novel geochemical exploration results of secondary mineral resources are presented. ral raw materials. the list of critical mineral raw materials is based upon two main criteria and includes mineral raw materials of great importance for the eu economy as well as mineral raw materials for which the global market supply has a potentially high risk. apart from the objectives mentioned above, following adop­ tion of the 17 sustainable development goals defined by the united nations (2015), the european commission has committed itself to apply these principles to all policies and initiatives of the european union. that mining can contribute to achieving sus­ tainable development goals was shown by the report on mining and sustainable development goals (2016). in accordance with the europe 2020 strategy, the european innovation partnership (eip) on mineral raw materials aims to increase the share of the industry to 20% of gdp. primarily, this will be achieved by reducing dependence on imports of mineral raw materials. in addition to this, the european commission is financing a number of projects related to mineral raw materials through horizon 2020. in the light of the above objectives, montenegro, as a candi­ date for eu membership, ought to harmonize its policy in the field of sustainable use and management of mineral resources with the policies at the european level. article history: manuscript received december 01, 2021 revised manuscript accepted april 19, 2022 available online october 17, 2022 keywords: primary and secondary mineral resources; montenegro; reseerve project; european geological data platform (egdi); inspire g eo lo gi a c ro at ic a geologia croatica 75/3336 from 2018 to 2021 the geological survey of montenegro (gsm) has been a participant in the ris reseerve project, which had as its main objective the inclusion of existing data from montenegro into the west balkan mineral register for primary and secondary mineral resources. during this three­year period, in cooperation with the geological survey of slovenia (geozs) as the lead partner of the ris reseerve project, the gsm team have firstly identified 57 of the most important primary and sec­ ondary mineral deposits and occurrences, with priority given to metals and industrial primary minerals deposits, as well as min­ ing, processing and metallurgical waste sites. subsequently, data have been updated for each mineral deposit and occurrence (the geological data ­ geological reserves, lithology, mineral and chemical composition, content of major and minor elements in the deposits; exploration activity, as well as spatial data) and mapped in accordance with the inspire directive. 2. metallogenic settings in geotectonic terms, the territory of montenegro belongs to the dinarides, while in the metallogenic sense it belongs to the di­ naric metallogenic province, that is to say to the sector of the northeastern mediterranean which is a part of the tethys eura­ sian belt (janković, 1974, 1977; janković & jelenković, 2000; janković et al., 2003). bordered by the southern alps in the northwest, the hellenides in the southeast, the adriatic sea in the southwest and the vardar zone in the northeast, the dinaric metallogenic province is characterized by numerous deposits and occurrences of mineral raw materials. the metallogeny of the dinarides and its features are presented in detail in janković & jelenković (2000) and references therein. in general the dinaric metallogenic province is considered to have a rather mod­ est mineral endowment, characterized by relatively small scale ore deposits, some metallic commodities are significant, notably bauxite, lead and zinc, iron and mercury. the oldest iron and manganese deposits originated in the caledonian metallogenic epoch, whereas siderite­barite­tetrahedrite deposits occur in rocks of carboniferous age and are characteristic of the hercyni an metallogenetic epoch. the formation of numerous economically important deposits of iron, lead and zinc, mercury, barium, and antimony, mostly occurring as hydrothermal­vein systems are related to the late permian­middle triassic period. karstic baux­ ite deposits are a distinctive feature of the dinaric province. pajović (2000a), states that the karstic bauxite formations in the dinarides were formed during fourteen terrestrial phases, eight of which are significant, namely those formed during the triassic, jurassic, lower and upper cretaceous, paleocene, eo­ cene, oligocene and neogene. a more detailed metallogenic zonation of montenegro was performed by pajović (1999), who defined the following zones: durmitor metallogenetic zone, high karst zone (which is subdi­ vided into kuči and old montenegrin metallogenetic subzone), the budva zone and the adriatic zone (fig. 1). within these metallo­ genetic units, he identified a further 17 ore regions, including a list of all known deposits and occurrences of mineral raw materials in the territory of montenegro. according to age, geological units in montenegro are classified into: caledonian­hercynian, palaeoal­ pine, mesoalpine and neoalpine. within the palaeoalpine middle triassic volcanic­sedimentary succession, nine lithological mem­ bers have been recognized as they are especially important for defining the formation of polymetallic (pb, zn, cu) mineralization in ne montenegro. all types of mineral raw materials in monte­ negro are shown on the map by special graphic marks, while ac­ cording to genetic criteria they are classified into seven environ­ ments and processes of ore formation. according to the time of their origin, they are classified into metallogenic epochs/periods. twenty­eight types of mineral raw materials have been identified so far in montenegro, fifteen of which have been exploited. 3. primary mineral resources of the 28 types of raw materials mentioned above, 23 were iden­ tified as having significant geological reserves, following inten­ sive geological exploration after the second world war, especially in the period from 1946 to 1986. the exploitation and processing of these natural resources have so far made an exceptional contri­ bution to the economic development of montenegro and continue to represent a reliable basis for further economic development. the following review of mineral raw materials of montenegro is based on data from various publications: gomilanović et al. (1999; 2003), pajović & radusinović (2010), gom (2021) and references therein. mineral resources of montenegro can be classified into dif­ ferent types of metallic, non­metallic minerals and energy raw materials, which also (according to national legislation) include groundwater, thermal and mineral waters. during the implementation of the reseerve project, spe­ cial emphasis was placed on significant primary deposits of me­ tallic mineral raw materials (figs. 1 and 2), their characteristics and geological features, as well as data relating to reserves and quality, all with the aim of forming a comprehensive database. the basic characteristics of the most important types and depos­ its of primary mineral raw materials in montenegro are presented here; non­metallic and energy raw materials are also included. 3.1. metallic mineral raw materials deposits of karstic red bauxites and deposits of lead and zinc ore have the greatest economic importance when considering the me­ tallic mineral raw materials of montenegro. it is estimated that new reserves and economically significant copper ore deposits could be proven by additional exploration at varine, near pljevlja. in contrast, the known occurrences of mercury, manganese, iron, titanium and chromium ores are currently assessed as economi­ cally uninteresting. deposits (with proven geological reserves) and occurrences of red bauxites are widely distributed in the central part, and to a lesser extent in the southern part of montenegro and represent the most important metallic mineral raw material. thirty depos­ its and many occurrences of red bauxites have been identified so far (pajović, 2000b). they were formed in three geological pe­ riods: the triassic, jurassic and early paleogene, with the juras­ sic bauxites having the greatest economic importance. they were discovered in the following regions: nikšićka župa, bjelopavlićke planine, banjani, bijele rudine and in the cuce­čevo area. how­ ever, the most important reserves of red bauxites are located in the nikšićka župa district, where the largest karst deposits of red bauxites have been discovered: liverovići i and ii, zagrad (fig. 3), kutsko brdo, đurakov do, biočki stan and štitovo i and ii (pajović et al., 2017). of the triassic bauxite deposits, the gornjopoljski vir deposit has been partially explored, while pre­ vious exploration in the palaeogene bauxites of the ulcinj area and in the luštica­grbalj terrain, did not provide a conclusive as­ sessment of their economic potential. proven geological reserves of different quality in bauxite de­ posits amount to about 35 mt in montenegro while estimates sug­ gest resources of about 60 mt. bauxite production from high­ quality deposits in the region of nikšićka župa which amounted g eologia c roatica radusinović et al.: the primary and secondary mineral resources of montenegro and their mapping into the european data model 337 to about 500,000 to 990,000 t/year in the last five years. the en­ tire bauxite production is currently exported, due to the closure of the alumina plant at podgorica in 2009. the presence of rare earth elements (ree) in significant concentrations in bauxite formations of different ages in monte­ negro was confirmed by recent exploration (radusinović, figure 1. map of the most significant mineral deposits and secondary mineral resources in montenegro (according to pajović & radusinović, 2010, modified and updated) with metallogenic regionalization (pajović, 1999). g eo lo gi a c ro at ic a geologia croatica 75/3338 2017; radusinović et al., 2017; radusinović & papa­ dopoulos, 2021), especially in the deposits and occurrences investigated in jurassic bauxites in the vojnik­maganik and pre­ kornica ore regions. this has opened new possibilities for more detailed exploration for new mineral resource in montenegro, where the mineral and economic potential and importance have yet to be determined. deposits and occurrences of lead and zinc in montenegro are related to the metallogenetic area of ne montenegro. eco­ nomic ore concentrations of these metals have been proven in figure 2. egdi map viewer, montenegro mineral register the part of the west balkan mineral register, reseerve project (egdi wbmr, reseerve, 2021), http:// www.europe-geology.eu/mineral-resources/mineral-resources-map/reseerve/. figure 3. the “zagrad”, nikšić bauxite mine. g eologia c roatica radusinović et al.: the primary and secondary mineral resources of montenegro and their mapping into the european data model 339 the mountainous terrain of ljubišnja ­ “šuplja stijena mine” and bjelasica ­ “brskovo mine” (janković et al., 2002). extensive detailed geological exploration has been carried out in the brsk­ ovo, žuta prla­razvršje and višnjica deposits in recent years, which have resulted in a significant increase in the total proven geological reserves and more reliable determination of the qual­ ity of the ores. the exploitation of lead and zinc ore, as well as the production of concentrates of these metals, and probably ad­ ditional concentrates of copper and accompanying precious met­ als, are expected to begin in the following years. the areas of the visitor and sjekirica mountains, where several economically in­ teresting ore occurrences have been found, have also been as­ sessed as highly prospective. the ore occurs in volcanic and vol­ canogenic­sedimentary rocks of middle triassic age with which it is invariably genetically and paragenetically associated. other occurrences of lead and zinc mineralization in clastic rocks of early triassic and palaeozoic age in ne montenegro have not yet been studied in detail, although some of them deserve attention. apart from the pyrite, sphalerite and galena in the triassic poly­ metallic sulfide mineralization, chalcopyrite ­ the main copper mineral in these ores (“šuplja stijena” and “brskovo” mines) is regularly present as an accompanying mineral. geological reserves of lead and zinc ore amount to about 50 mt in montenegro. the estimated prospective resources are about 40 mt in all the above mentioned ore regions. the production ca­ pacity of lead and zinc ore in the “šuplja stijena” mine (fig. 4), has stabilized in the last five years and amounts to between 540,000 to 590,000 t/year. an average of 18,500 t/year of lead concentrate and 4,700 t/year of zinc concentrate were produced in the same period. according to the mine operator ś plans, the production capacities of ore and concentrate at the “brskovo” mine will be significantly higher. the most significant concentrations of copper ore in mon­ tenegro were discovered at varine (near pljevlja). mineralization occurs in jurassic diabases and pyroclastics, in the form of hy­ drothermally altered ore zones, with ore veins (pyrite, chalcopy­ rite, quartz), layered­lenticular thin ore bodies (pyrite and chal­ copyrite) and impregnations of pyrite with accompanying chalcopyrite. in addition to the above, rare, narrow veins of chal­ copyrite ore have been discovered in clasts in lower triassic sediments in the šćepan polje district, as well as in palaeozoic sediments in kukića bor (near plav). these copper mineraliza­ tions have been assessed as economically insignificant. mercury ore (mineral cinnabar) has been observed in mid­ dle triassic volcanic rocks in the krnja jela area near boan, in middle triassic volcanogenic­sedimentary rocks in bjelojevići and brskovo near mojkovac, in lower triassic sediments in spič near sutomore and in the kovač mountain area near pljevlja. mineralization occurs as three types: as monomineral (followed by pyrite), in paragenesis with barite and together with polyme­ tallic sulfides. the economic reserves of mercury have not been proven. over 20 occurrences of iron have been discovered in mon­ tenegro, of which the most important are in sozina (sutomore), klini (konjusi near andrijevica) and kozica (pljevlja). manganese occurrences have been discovered in the coastal part of montenegro as well as on sinjajevina mountain but are considered to have no economic value. occurrences of titanium and chromium minerals were dis­ covered in coastal sands at ulcinj, in the area between the shore­ line, the river bojana and štoj. these sands contain: chromite, ilmenite, zircon, magnetite, apatite and other minerals. the pos­ sibility of titanium and chromium valorisation from the sands of ulcinj has not yet been investigated. figure 4. the lead and zinc mine at “šuplja stijena”, pljevlja. open pit, waste rock dump and flotation tailings. g eo lo gi a c ro at ic a geologia croatica 75/3340 3.2. non-metallic mineral raw materials non­metallic mineral raw materials, both industrial minerals and construction materials, are becoming increasingly important in the mineral economy of many developed countries. twelve types of non­metallic mineral raw materials of eco­ nomic importance have been identified in montenegro, as fol­ lows: architectural­building (natural) stone, technical­building stone (crushed rock­ aggregates), gravel and sand, brick clays, cement marl, white bauxite, dolomite, barite, bentonite, quartz sand, chert and sea salt. nine of them have been utilised to date, while the dolomites, quartz sand and chert are unexploited. natural stone for architectural building and ornamentation is one of the most important non­metallic mineral raw materials in montenegro. all deposits of architectural­building stone are within carbonate rocks (limestones, dolomitic limestones, lime­ stone breccias, etc.) which comprise about 70% of the territory of montenegro. also, there is significant potential for using vol­ canic rocks for decorative purposes. the carbonate rocks in which more than 20 natural stone deposits have been identified so far are of triassic, jurassic, cretaceous and neogene ages. the most important deposits occur in late cretaceous carbonate for­ mations in the bjelopavlići ore region (božović et al., 2018). according to test results, natural stones from montenegran de­ posits are mainly suited to the production of slabs for interior and exterior cladding of horizontal and vertical surfaces, as well as for the production of stone accessories, kerbstones and other elements in construction. proven natural stone resources in montenegro amount to about 20.5 mm3. production currently occurs in six quarries, with average amounts about 10,000 m3 of commercial natural stones being extracted annually. tufa is a specific type of natural stone that forms in proxim­ ity to waterfalls and cascades. due to its extremely favourable physical, technical and decorative characteristics, tufa has been used as a building material since ancient times. medieval churches and other sacred buildings, monuments and buildings of national importance in montenegro were mainly built from this type of natural stone. the most important deposits in mon­ tenegro are located at tavani (šavnik), gornja lijeska (tomaševo) and in zbljevo (pljevlja). the technical-building stone in montenegro is mainly pro­ duced from carbonate rocks ­ limestones, dolomitic limestones and dolomites, with only one deposit in which volcanic rocks are exploited (štitarica near mojkovac). more than 40 deposits have been defined so far. the largest number of technical­building stone deposits are located in the coastal part of montenegro, which is also the area with the fastest development and the most inten­ sive construction activity, and consequent demand for resources. proven geological reserves of technical­building stone in montenegro amount to about 90 mm3. the average annual pro­ duction of stone aggregates used for the production of concrete, asphalt and other purposes, from 23 active quarries is about 0,6 mm3. a further specialized possibility for valorization of technical and architectural building stone resources, providing that they are of carbonate composition, is in the production of carbonate fillers, which have various industrial applications (božović et al., 2016). gravel and sand are exploited from alluvial sediments in riverbeds as well as, to a lesser extent, from glaciofluvial depos­ its in karst fields. the most important deposits of brick clays in montenegro are located in neogene lake sediments with coal, in the areas of pljevlja, maoče and berane. significant reserves of this mineral raw material have been proven by exploration in the localities of maljevac and maoče near pljevlja, and also in budimlja near be­ rane (drobnjak et al., 2003). alluvial deposits represent the second genetic type of clay deposits in montenegro. they have been explored throughout almost the entire area of montenegro, while estimates of the reserves of this mineral raw material have been determined in the following places: kukavički vrh near bi­ jelo polje, donje lipovo near kolašin, moromiš and stanjevića rupa near danilovgrad, sinjarevo and zekova glavica near tivat and finally in ćurke near ulcinj. exploitation and processing of clay into brick products in the second half of the 20th century was occasionally carried out at pljevlja, berane, tivat, spuž, kolašin, bijelo polje, virpazar, šavnik, amongst others. there have been no active clay mining operations in montenegro in recent years, nor production of brick building materials and the value of an­ nual imports of non­refractory ceramic bricks is about 25 meur (monstat, 2021). the production of cement in montenegro took place in plje­ vlja during the period 1976­1988, when the cement factory closed. during the 13 years of operation 1,66 million tons of cement was produced. the marl from the hanging wall of the potrlica coal deposit was the main material supplying this factory and this still represents an assured, high­quality resource for the long­term development of the cement industry. deposits of cement marl with more heterogeneous composition have also been proven in the vicinity of gradina near danilovgrad as well as at donja klezna near ulcinj. white bauxites are a rare mineral raw material in which clay minerals (mostly kaolinite) are mixed with aluminium hydroxides (boehmite, rarely hydrargillite) and iron oxides (haematite, goe­ thite). more than 100 deposits and occurrences of this mineral raw material have been discovered in montenegro, more precisely in western montenegro, within an area of about 1,000 km2 ­ be­ tween nikšić, čevo, dragalj, the river trebišnjica and the golija mountain. dolomite, like limestone, is a mineral resource with great potential in montenegro. unfortunately, the issue of industrial use of dolomite has not yet been resolved and so far, only four dolomite deposits have been proven by exploration: virpazar, vranjina, šume near gornje polje and bršno near nikšić. barite deposits are concentrated in the ore region of kovač mountain, in the far northwest of montenegro, in the vicinity of potkovač, plakalo, plana and arslanovina. exploitation of barite from potkovač was carried out in the period 1948­1956. the most important bentonite deposits have been found in the coastal part of montenegro, bijelo polje and bijele šume above petrovac and in the central part of montenegro, at donja bukovica near šavnik. however, bentonite has only been ex­ ploited from the bijelo polje deposit, where detailed geological and technical investigations have been renewed in recent years, with the aim of determining the possibilities for use in various industrial applications. deposits of quartz sands in montenegro have only been found in the miocene sediments around ulcinj (localities: zoganje, škaret and zekova šuma). quartz sand from these de­ posits has not yet been exploited. the vrdola chert deposit is situated on the northern slope of vrmac hill, about 3 km northeast of tivat. it consists of platy and g eologia c roatica radusinović et al.: the primary and secondary mineral resources of montenegro and their mapping into the european data model 341 thinly laminated jurassic­cretaceous cherts, clays, silicified lime­ stones and calcarenites. silicate sand, obtained by processing the cherts, can be used in the glass and refractory industries, for ob­ taining abrasives, in construction and the chemical industry. salt has been prodcued from sea water in montenegro at the “bajo sekulić” saltworks in ulcinj, by natural (solar) and indus­ trial (thermocompression) evaporation. 3.3. energy raw materials economically interesting coal (lignite) deposits in montenegro occur in the neogene lacustrine pljevlja and berane coal basins. in the strictest sense, the pljevlja basin includes the potrlica de­ posit as well as kalušići, komini, grevo and rabitlje. the plje­ vlja area also contains coal­bearing basins: ljuće­šumani, ma­ taruge, otilovići and bakrenjače, glisnica and maoče. coal is being exploited from the potrlica deposit (fig. 5) and used for the needs of the pljevlja thermal power plant. coal reserves in the pljevlja basin are about 50 mt, while the maoče basin is estimated to contain about 110 mt; other smaller basins contain a total of about 11 mt. the production of coal from the potrlica open pit is designed to meet the requirements of the pljevlja thermal power plant (tpp), which during the last five years has been about 1.6 mt annually . there are several coal deposits in the berane basin: budim­ lja, petnjik, zagorje and berane. the police coal basin can also be considered to be part of the berne basin. coal from the petnjik deposit is exploited as an underground mine but its complex tec­ tonic structure significantly complicates the possibility of apply­ ing mass excavation methods. the geological reserves of coal in the berane basin are about 25 mt, while in the police basin they are about 12 mt. the average annual production of the petnjik underground mine is only about 150,000 t. oil and gas exploration on the mainland of montenegro be­ gan in 1949. while offshore exploration began in 1970. seventeen exploration holes have been drilled on the mainland, while 4 deep exploration boreholes have so far been drilled offshore. in addi­ tion, extensive geophysical exploration has been carried out off­ shore. the results of previous exploration show that in this area, conditions were favourable for the formation of hydrocarbon de­ posits. preliminary exploratory drilling under new exploration programs is underway, and the first results are expected this year. 4. secondary mineral resources mining, minerals and metals production has left a significant legacy in the landscape of montenegro. the mining and metals processing industries represented some of the most important economic activity in montenegro, from 1950 to 1990. (gomilanović et al., 1999; 2003). the most important min­ ing areas are nikšić, where the exploitation of bauxite is taking place, pljevlja with significant production of lead and zinc con­ centrates and coal, and mojkovac, where lead and zinc concen­ trates were produced from 1976 to 1991. in addition, there has been production of steel and iron based on secondary resources in the nikšić steel plant and the podgorica aluminum plant pro­ duces aluminium (fig. 6). lottermoser (2007) classifies mine waste as: mining waste, processing waste, metallurgical wastes and mine waters. mining wastes include: waste rocks, overburden and spoils from the process of exploitation of mineral deposits. this group in montenegro includes: cement marlstone and limestone from the hanging wall of the “potrlica” coal deposit; carbonate rocks from bauxite open pits in the wider area of nikšićka župa; carbonate and volcanic rocks from the «šuplja stijena» lead and zinc open­ cast mine. flotation residue material from the «šuplja stijena» and «brskovo» lead and zinc mines as well as bauxite residue (red mud) from alumina plant podgorica belong to processing wastes. metallurgical waste includes rocky sand and slag fom the figure 5. the coal mine at “potrlica”, pljevlja. g eo lo gi a c ro at ic a geologia croatica 75/3342 nikšić steel plant. the bottom and fly ash from the thermo power plant pljevlja are classified in the tpp waste group. it is obvious that care of the environment has not always been a matter of priority. however, montenegro took steps to address environmental issues by declaring itself as an “ecological state” in 1991. based on the previously mentioned objectives and in ac­ cordance with legal regulations, the remediation of so­called “black ecological points” was initiated by tackling the flotation tailings dam in mojkovac and gradac near pljevlja; the red mud tailings dam in podgorica; tpp waste dump maljevac near plje­ vlja as well as the metallurgical waste dump from the nikšić steel plant (epa, 2014). the flotation tailings dam remediation in mo­ jkovac has already been completed, while the rehabilitation and remediation of the tpp waste dump maljevac and the gradac flotation tailings dam is in progress. although the previously mentioned environmental objec­ tives and national regulations in montenegro require remediation of mining wastes, they are also regarded as so­called “techno­ genic mineral raw materials”, i.e. secondary mineral resources (gomilanović et al., 1999; 2003). 4.1. processing wastes – red mud (bauxite residue) tailings, aluminum plant podgorica bauxites in montenegro have been used for the production of alu­ mina and aluminium from 1972 to 2009. during this period, 16.6 mt of bauxite was processed in the podgorica aluminium plant, while 6.8 mt of alumina and 3.1 mt of aluminum were produced (radusinović &papadopoulos, 2021). after bauxite processing, the main by­product is red mud ­ bauxite residue, which was disposed of in two large open tailings dams next to figure 6. location map of primary mineral resources (prm) (bauxite and pb-zn deposits) and secondary mineral resources (srm) in montenegro. g eologia c roatica radusinović et al.: the primary and secondary mineral resources of montenegro and their mapping into the european data model 343 the factory (fig. 7). the total quantity of bauxite residue is about 7,5 mt. this material is characterized by high alkalinity and a high iron content. red mud is classified as a hazardous waste and it presents a potential threat to the environment, especially to groundwater, according to data relating to hazard elements and pollutants. apart from the significant abundances of major elements: fe, al, si, and sometimes ca and na, red mud contains increased concentrations of trace elements, especially rare earth elements (ree). an average ree content of 1535 ppm was determined for red mud in basin a at podgorica, while the average content de­ termined in basin b was 1646 ppm, according to tomašić et al. (2020). the total average content of rare earth elements (∑sc, y, la­lu) in the bauxite residue in basins a and b is 1.4 times higher than the average content in bauxites. the largest increase in average content is shown by sc, la and ce (radusinović & papadopoulos, 2021). based on some of the criteria developed within the frame­ work of the reseerve project, sampling in the field and labo­ ratory testing, these tailings sites have been characterized as po­ tential sources for trace element extraction and recovery. the concentrations of 65 elements in tailings samples have been analysed by icp­ms in bureau veritas commodities can­ ada ltd. (accredited under iso 9001:2015) after aqua regia diges­ tion (at 95 °c, using the 1dx method) and total 4­acid digestion following international standards (iso 14869­1:2001, 2001). in the area of the red mud landfill at podgorica, concentra­ tions of ree exceeding 1200 mg/kg ree (mostly ∑sc, y, la­lu) were discovered. deviations from these observed concentrations are attributable to different sampling techniques, sample prepa­ ration and analytical methods used. the podgorica red mud tail­ ings dam could warrant further investigations, and above all, the application of ree extraction methods might be commercially interesting (tab. 1). in addition, bauxite residue can also be used in the cement and concrete industries, as inorganic polymers as well as in other novel applications, as catalysts, polymer composites, or adsor­ bents. 4.2. processing wastes – tailings at gradac and “šuplja stijena mine”, lead and zinc flotation residue material the šuplja stijena underground mine produced more than 4 mil­ lion tons of ore and about 76,000 t of lead concentrate and 300,000 t of zinc concentrate, between 1954 and 1987. about 3.5 million tons of residue materials after flotation have been accumulated at the gradac tailings dam over many years (fig. 8). recent results of the solid phase analysis showed that metals, such as lead and zinc, are present at concentrations below 1%, which is currently considered insufficient for cost­ef­ fective re­processing of this material. the material from the gradac tailings has been tested sev­ eral times, and potential opportunities for its use occur in the ce­ ment industry, the production of plaster and the production of table 1. average concentration of some elements in srm deposits – montenegro. digestion unit podgorica gradac šuplja stijena nikšić ag total mg/kg 0.25 3.2 2.9 3.1 au ar µg/kg 0.20 80 62 1.2 cr total mg/kg 720 42 43 4200 cu total mg/kg 110 320 140 460 mo total mg/kg 2.5 0.46 0.43 93 ni total mg/kg 260 24 28 290 pb total mg/kg 230 1900 1400 850 zn total mg/kg 350 4100 4700 1500 ree total mg/kg 1200 55 52 42 figure 7. red mud bauxite residue tailings dams, podgorica. g eo lo gi a c ro at ic a geologia croatica 75/3344 silicate bricks (gomilanović et al., 1999). however, there have been no commericial attempts to use the tailings for any of these purposes so far. after recommencement of production in 2010, more flotation tailings dams were constructed near the šuplja stijena mine, com­ pleted by applying several layers of materials of appropriate chara cteristics. surface samples of material from the abandoned gradac and the active šuplja stijena tailings deposits were also collected and analysed. slightly elevated concentrations of ag (3.2 mg/kg ­ gradac and 2.9 mg/kg ­ šuplja stijena) and relatively high con­ centrations of zn (0.41% ­ gradac and 4.7 mg/kg ­ šuplja stijena) could possibly warrant further investigations (tab. 1). neverthe­ less, these values are much lower in comparison with many other areas that were studied in the project. thus, the tailings do not appear to be promising from the commercial perspective. 4.3. tpp wastes – waste dam maljevac – bottom and fly ash from tpp pljevlja the thermal power plant pljevlja produces about 350,000 t of bottom and fly ash annually. about 10 million tonnes of this ma­ terial have been disposed of as a tpp waste dam at maljevac dur­ ing the last 35 years (fig. 9). there are many positive benefits of using ash, the first being that removing the ash from the waste dam contributes to environmental remediation as well as provid­ ing financial gain. fly ash is already widely used by the global cement and con­ crete industry. by conducting more tests and investment, a sig­ nificant environmental issue in montenegro could be solved while also exploiting these resources for the production of build­ ing materials. however, current information indicates that the maljevac tpp waste dam will be closed soon and due to the lack of capac­ ity, site remediation has already begun. the new tpp waste dam will be in the area of the former open­cast coal mine at ljuce­ šumani. 4.4. mining wastes – waste rocks dump jagnjilo, pljevlja – cement marlstone and limestone from the “potrlica coal mine” natural cement marlstone and limestone, up to 130 m thick, over­ lies coal layers in the potrlica deposit (fig. 5). more than 80 mt of these rocks have been excavated and redeposited at the jagnilo mining waste rocks dump in the vicinity of the potrlica open pit, and represents a significant secondary resource (fig. 10). there is no doubt that there are exceptional natural condi­ tions for long­term cement production and development of the construction industry based on this and other mineral raw mate­ rials in the pljevlja basin. technological advances in cement pro­ duction, quality basic mineral raw material, energy fuel and ad­ ditives all offer significant potential for the development of this important industry for montenegro, which currently annually im­ ports portland cement worth about 40 meur (monstat, 2021). 4.5. metallurgical waste dump, nikšić steel plant the steel plant nikšić was founded in 1956. the metallurgical waste dump is situated 2,5 km from the factory and has also been in use since 1956. it consists of two parts with more than 3 mm3 of materials (based on estimation), described as a mixture of rocky sand with ash and slag, as well as other waste material, which has been deposited without any regulatory supervision (fig. 11). the largest proportion of material from the steel factory con­ sists of ash from the thermoelectric furnace and sludge from the water treatment plant, as well as ash and slag from foundry sand. these materials contain potentially toxic metals, as well as other contaminants but after appropriate treatment, they could be suc­ cessfully used as an aggregate component in asphalt production. the analytical results of surface samples of metallurgical slag collected from the waste dump are merely indicative because of the very coarse­grained texture of the sampled material. analy ses yielded 3.1 mg/kg ag and 0.42% cr (tab. 1). from the commercial perspective, this waste dump is not attractive for further metal extraction. figure 8. flotation tailings dam at “gradac”. g eologia c roatica radusinović et al.: the primary and secondary mineral resources of montenegro and their mapping into the european data model 345 4.6. mining wastes – waste rocks at nikšićka župa and “šuplja stijena mine” with respect to secondary aggregates comprising waste rocks of carbonate composition, the largest volumes originate from baux­ ite open pits in the wider area of nikšićka župa. the total exca­ vated quantity (limestone, dolomite limestone and glacial gravel and sand) of waste rocks dumps deposited in the past 60 years at several locations are about 50 mt. some of the material is used for infilling of the abandoned open pits from exhausted deposits of bauxite. a significant part of this material could be used for the production of aggregates. formerly, there was an attempt at such aggregate production on a small scale at a location near nikšić but there is no production at present. exploitation of about 5 mm3 of overburden of carbonate composition in the active lead and zinc open pit “šuplja stijena mine” was also planned. mining waste of carbonate composition is disposed of separately and can potentially be used for aggre­ gate production (fig. 4). other uses, such as carbonate fillers, lime and the cement industry are also possible. 5. mapping – methodology and results the aim of this work was to integrate the national data of mon­ tenegro into the already existing european platform egdi and present them on the web portal. this represents the starting point for following the inspire directive and obtaining a strong de­ cision­making tool for the management of mineral resources in montenegro. figure 9. the tpp pljevlja waste dump “maljevac”. figure 10. the waste rock dump “jagnjilo”. g eo lo gi a c ro at ic a geologia croatica 75/3346 as the overall eu strategy is to reduce dependency on raw materials from “abroad”, it is necessary to standardize the data between the individual countries at eu level. that goal was in­ stigated by the directive of the european parliament and of the council on the establishment of an infrastructure for spatial in­ formation in the european community, known as the inspire (infrastructure for spatial information in europe) directive, which became valid from 15th may 2007. inspire regulates the baseline for the establishment of a european infrastructure for spatial and environmental data in the member states. such infra­ structure enables the institutions and stakeholders to share infor­ mation and knowledge, and to find, view and acquire, standardi­ zed and harmonized geo­referenced and related data, including data on mineral resources. it integrates the best available mineral expertise and information based on the geological knowledge, in support of public policy making, industry, society, communica­ tion and education purposes at an international level (inspire, 2007). the work was mostly focused on workflows for harmoniz­ ing the data and dissemination of information technology (it) knowledge for mapping the national primary and secondary min­ erals data of montenegro to the already existing european data model and developing a national relational database, that fits within the european common database structure. data harmoni­ zation was performed through two national training workshops, designed to make the first step toward inspire directive imple­ mentation. for reaching the final harmonization of data the following methodology has been used: engineering of end users’ requirements the first step was the analysis of end user needs. the end users are different,and they have different requirements. this phase was realized through questionnaires. qualitative and quantitative research of data to achieve this purpose, an excel summary table was designed for the collection of national data on primary and secondary min­ eral raw materials, relevant for potential investors. a table with common attributes, using a top­down approach (from general to detailed information) has been completed. the table includes attributes such as basic geographical and ownership information about each site, geometry, volume, mining data such status, min­ ing methods and reserves, geological data such as stratigraphy and lithology, mineral composition and rock types, stability, chemical composition and environmental impacts . overview of existing eu data model and harmonizing the basic excel table fields with the inspire database fields national data have been harmonized with the inspire data model and online services for data on mineral raw materials have been established. to accomplish this, we examined the inspire directive in detail, identified the fields that coincide with the di­ rective, and adapted them accordingly to the requirements. mapping the basic excel table to inspire customized excel tables/ harmonization of existing data to inspire-compliant data at this stage, it was necessary to consider the specific rules re­ quired by the common data model. the data must be entered in an exact sequence, for this purpose the instructions for inserting data were also compiled. it is necessary to follow the provided inspire code lists for interoperability with the existing egdi platform, use the specific record identifiers and correctly track the relationships between the data. this stage of work has been carried out in two national work­ shops/training courses with technical support to acheive harmo­ nization of data sets into inspire compliant data and working with relational databases. figure 11. metallurgical waste dump, nikšić steel plant. g eologia c roatica radusinović et al.: the primary and secondary mineral resources of montenegro and their mapping into the european data model 347 mapping inspire customized excel tables to the access relational database this phase was relatively simple since the pre­existing excel ta­ bles have been organized in the same way as a relational database and the data were only copied to the tables one by one. because the access database is already a relational database and all the errors, made in the excel table appear, it also provides good con­ trol of the data entry itself. national workshops have also been carried out for this purpose. mapping access database into postgresql the next step was the migration of national access databases to open­source solutions (postgresql database, used by the pro­ ject). harvesting national databases to the common eu database to create a system with updated data, the project adopted a distributed architecture based on a central harvesting database synchronized with a central database. data harvesting is the pro­ cess of automatically extracting large amounts of data from web services. geozs implemented a harvesting system to collect and validate inspire compliant spatial european data of mineral resources (fig. 12). at an individual country level the national provider distributes their data as a web feature service (wfs), so that the geozs harvesting system retrieves this data, performs data transformation and quality control, and finally stores vali­ dated data in the central database (minerals4eu, 2014). presentation of data on the egdi web portal in addition to the map service displaying mineral deposits and mines on the egdi portal, the portal also provides occurrence­ specific documents related to mineral materials, enabling users to make their own analyses from a huge amount of data (fig.2). it represents a new knowledge base of regional primary and sec­ ondary resources which is also interoperable with national data­ bases. the purpose of this, is to encourage industry to invest in the west balkan mineral sector (egdi, 2021). data for a total of 53 primary mineral resources (prm), in­ cluding 35 mines and 4 secondary mineral resources (srm) were collected and harmonized in montenegro. the register allows information related to primary and sec­ ondary mineral resources to be combined easily and for delivery of all the available information to the end users. the data platform represents a first step towards future effective and sustainable in­ formation systems for the region. the technical solutions also facilitate data update and maintenance and gives a full access to information related to the entire life cycle and value chain of mine ral resource. 6. conclusions what is the economic and social importance of mineral produc­ tion in montenegro? statistics show that in recent years the min­ ing industry has contributed less than 2% to national gdp and employs less than 2,000 workers. it should be noted that coal is mostly used for electricity production ­ approximately half of montenegro’s production, while bauxite, aluminum and lead and zinc concentrates are the most important export products of mon­ tenegro. it is evident that montenegro, in relation to its size, possesses significant primary and secondary mineral resources, primarily bauxite, lead and zinc ores and coal, as well as raw materials for the production of cement, bricks and ceramics and other con­ struction materials and industrial minerals. the potential for the enhanced usage of raw materials such as brick clays, cement marl, dolomite, barite, bentonite, quartz sand, chert, sea salt, undoubt­ edly exists, as demonstrated by the documentation of numerous deposits and proven reserves, as well as the historical evidence that most of these raw materials have been previously exploited or processed industrially . the basic question is one of economic justification and investor interest in commencing production of some of the listed mineral raw materials. at present, the most significant and most promising are the reserves of cement marls in potrlica and jagnjilo (secondary mineral raw materials), as well as bentonite in the deposits of bijelo polje and bijele šume on paštrovačka gora and barite in the area of kovač. nevertheless, in recent years, montenegro has been import­ ing various mineral commodities with an annual worth on aver­ figure 12. architecture of the harvesting system. g eo lo gi a c ro at ic a geologia croatica 75/3348 age of around 335 million euros per year, which is a significant burden for a small economy, otherwise mainly reliant on tourism and services. long­term planning and management of the mineral sector in accordance with the principles of sustainable development could significantly contribute to the diversification of the monte­ negran economy as well as increase the economic stability. we believe that one of the ways to draw attention to this potential is to include data on the mineral resources of montenegro in the european database, as has been done through the ris rese­ erve project. in addition, it is necessary to promote investment possibilities in exploration and exploitation of mineral resources and processing capacities, with respect to both metal production and industrial minerals and construction materials from primary and secondary deposits. acknowledgement national research projects: ‘metallogenetic map of montenegro, 1:200,000’ were financed by ministry of economy of montene­ gro, now ministry of capital investments of montenegro trough the programs of geological exploration in montenegro, which is kindly acknowledged. our special gratitude goes to the european institute of innovation and technology (eit) for funding the pro­ jects: ‘ris reseerve ­ mineral potential of the esee region, ‘reebaux—prospects of ree recovery from bauxite and bauxite residue in the esee region’ and ‘ris restore – evalu ation of red mud tailings in the esee region‘. this body of the european union receives support from the european union’s horizon 2020 research and innovation programme. the geological survey of montenegro has been a partner of these eit raw materials projects in recent years. photographs: the author of all photographs printed in this article is slobodan radusinović, except fig. 10 whose author is branislav vuković. references božović, d., radusinović, s. & simić, v. (2018): carbonate mineral raw ma­ terials of montenegro.– in: proceedings of the 17th serbian geological congress with international participation, vrnjačka banja, serbia, may 17–20, 2018; ser­ bian geological society: belgrade, serbia, 263–268. doi: 10.2298/ hemind150325054b božović, d., simić, v., radulović, d., abramović, f.b. & radusinović, s. (2016): carbonate filler resources of the bjelopavlići area, montenegro.– hem. ind. 70/5, 493–500. doi: 10.2298/hemind150325054b drobnjak, m., simić, v. & blečić, n. (2003): kvalitet glina u ležištu budimlja (beranski tercijarni basen).– izgradnja, 57/5, beograd, 175–177. egdi (2021): about egdi, http://www.europe­geology.eu/about­egdi/ egdi ­ wbmr, reseerve (2021): west balkan mineral register, reseerve pro­ ject, http://www.europe­geology.eu/mineral­resources/mineral­resources­map/re­ seerve/ environmental protection agency of montenegro ­ epa (2014): upravljanje industrijskim otpadom i čišćenje – iwmcp – www.rio.org.me https:// epa.org.me/2014/03/21/upravljanje­industrijskim­otpadom­i­ciscenje­iwmcp/ european commision ­ ec (2020): communication from the commission to the european parliament, the council, the european economic and social committee and the committee of the regions critical raw materials resilience: charting a path towards greater security and sustainability; com/2020/474 final, european commision, brussels, belgium. (https://ec.europa.eu/docsroom/documents/42849) gomilanović, m., blečić, n., kaluđerović, m., manojlović, m., pajović, m., radulović, v., simić, r., kalezić, m., kovačević, v., ostojić, m., et al. (1999): mineralne sirovine i rudarska proizvodnja u crnoj gori.– ministarstvo industrije, energetike i rudarstva, podgorica, crna gora, 804 p. gomilanović, m., pajović, m. & kalezić, m. (2003): complex of mineral resources in montenegro.– in: vujić, s. (ed.): mineral material complex of ser­ bia and montenegro, monograpf. fac. min. geol. belgrade, engineering academy of yugoslavia & union of engineers of mining and geology of serbia and mon­ tenegro, section of mining an geology sciences, special issue no. 2, belgrade, 201–227. government of montenegro ­ gom (2021): state plan of mineral resources exploitation.podgorica, montenegro. (https://www.gov.me/dokumenta/ce2adeb5­ cc95­4a4b­b765­718795acd699) inspire (2007): directive inspire. about inspire, 2007, https://inspire.ec.europa. eu/about­inspire/563 janković, s. (1974): metalogenetske provincije jugoslavije u prostoru i vremenu (opšti pregled).­ in: savetovanje “metalogenija i koncepcija geotektonskog raz­ voja jugoslavije”, beograd, feb. 27–28, 1974., rudarsko­geološki fakultet: beo­ grad, srbija, 31–52. janković, s. (1977): major alpine deposits and metallogenic units in the ne medi­ terranean and concepts of plate tectonics.– in: janković, s. (ed.): metallogeny and plate tectonics in the ne mediterranean, belgrade, dec. 7–9, 1976.­ igcp­ unesco/correlation project no. 3. fac. min. geol. belgrade, 105–172. janković, s. & jelenković, r. (2000): metallogeny of the dinarides.– in: kar­ amata., s & janković, s. (eds.): proceed. int. simp. “geology and metal­ logeny od the dinarides an the vardar zone”, zvornik, oct. 3–6, 2000. acad. sci. arts rep. srpska, dpth. math. nat. tech. sci., vol. 1, banja luka ­ srpsko sara­ jevo, 281–305. janković, s., jelenković, r. & vujić, s. (2003): mineral resources and poten­ tial prognosis of metallic and non­metallic mineral raw materials in serbia and montengro at the end of the xxth century.– enginerering academy of serbia and montenegro, section of mining an geology sciences, special issue no. 2, belgrade, 1–875. janković, s., pajović, m. & svrkota, r. (2002): gelogija i metalogenija br­ skovskog rudnog polja, bjelasica (crna gora).– inženjerska akademija jugoslavi­ je, odelenje rudarskih i geoloških nauka, posebno izdanje br.1, beograd, 253 p. lottermoser, b.g. (2007). mine wastes: characterization, treatment and environ­ mental impacts, 2nd edition.– springer, berlin. minerals4eu (2014): the eu­mkdp (minerals knowledge data platform), 2014, htt­ ps://www.slideshare.net/minerals4eu/minerals4­eu­wp51stmincecon­ f20141126dcassard pajović, m. (1999): metallogenic map of montenegro, 1:200.000.– separate issues of geological bulliten, vol. xvi, podgorica, montenegro (printed in color on two b1 format sheets). pajović, m. (2000a): genetic model of the karstic bauxites in the dinarides.– in: karamata, s. & janković, s. (eds.): proceed. int. simp. “geology and metal logeny od the dinarides an the vardar zone”, zvornik, oct. 3–6, 2000. acad. sci. arts rep. srpska, dpth. math. nat. tech. sci., vol. 1, banja luka ­ srpsko sarajevo, 365–374. pajović, m. (2000b) geology and genesis of red bauxites of montenegro.– separate issues of geological bulletin. geological survey of montenegro: podgorica, mon­ tenegro, volume xvii, 242 p. pajović, m., mirković, m., svrkota, r., ilić, d. & radusinović, s. (2017): geology of vojnik­maganik bauxite­bearing region (montenegro).– geo­ logical survey of montenegro, separate issues of geological bulletin, podgorica, montenegro, 339 p. pajović, m., radusinović, s. (2010): mineral resources of montenegro.– in: mon­ tenegro in the xxi century ­ in the era of competitiveness, the living environ­ ment and sustainable development; special editions (monographies and studies), tom 2, canu; montenegrin academy of sciences and arts, podgorica, monte­ negro, volume 73, 237–282. radusinović, s. (2017): metallogeny of jurassic karstic bauxites of vojnik­maga­ nik and prekornica mining areas, montenegro.– unpubl. ph.d. thesis, university of belgrade, faculty of mining and geology, belgrade, serbia, 349 p. radusinović, s., jelenković, r., pačevski, a., simić, v., božović, d., holclajtner­antunović, i. & životić, d. (2017): content and mode of occurrences of rare earth elements in the zagrad karstic bauxite deposit (nikšić area, montenegro).– ore geol. rev., 80, 406–428, doi: 10.1016/j.oregeor­ ev.2016.05.026 radusinović, s. & papadopoulos, a. (2021): the potential for ree and as­ sociated critical metals in karstic bauxites and bauxite residue of montenegro.– minerals, 11, 975–1018. doi: 10.3390/min11090975 statistical office of montenegro – monstat (2021): podgorica, mon­ tenegro. https://www.monstat.org/cg/ tomašić, n., gielisch, h., grbeš, a., gawlick, h.j., mindszenty, a., mladenovič, a., bedeković, g., sobota, i., ivić, i., lowicki, f., & reebaux project team: bedeković, m., biró l., bódi, l., čobić, a., durn, g., fajković, h.,gizdavec, n., gverić, z., ilijanić, n., ivkić i., kovačević galović, e., lesko, m., madai, f., miko, s., moricz, f., nagy, v.z., radusinović, s., szabó, c., teskera. d., turk, j., veinović, ž., vlahović, i. & zalar serjun, v. (2020): baux­ ite and bauxite residue as a potential resource of ree in the esee region–book­ let.– in: tomašić, n. (ed.): kava reebaux–prospects of ree recovery from bauxite and bauxite residue in the esee region–eit rm , university of zagreb, faculty of science, department of geology, zagreb, croatia, 86 p. 2021 | 74/3 | 305–318 | 11 figs. | 3 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society evaluation of 3d small-scale lithological heterogeneities and pore distribution of the boda claystone formation using x-ray computed tomography images (ct) saja m. abutaha1, jános geiger1, sándor gulyás1 and ferenc fedor2 1 university of szeged, department of geology and paleontology; 6722, szeged, egyetem utca 2-6, hungary; (sajaabutaha@geo.u-szeged.hu, matska@geo.u-szeged.hu, gulyas.sandor@geo.u-szeged.hu). 2 geochem ltd, 55/1 viola str., kozármisleny, h-7761, hungary; (fedor.ferenc@geochem-ltd.eu) doi: 10.4154/gc.2021.17 abstract this study was undertaken to quantify and evaluate the density and porosity characteristics of a boda claystone formation (bcf) core sample using medical ct. each voxel of the 3d ct volume was described with three variables: dry ct number, saturated ct number, and effective porosity. disparity pore voxels were revealed using the genetic groups’ algorithm of data-mining techniques. the k-fold cross-validation algorithm has been applied to determine the number of the most stable cluster. the 3d spatial distributions of voxel-porosity by rock constituents, as well as the 3d distribution of porosity clusters by rock components, were found by boolean function implementation. the terrigenous detrital fragments had the lowest porosity mean (0.16%) and highest coefficient variation value (1039.39%). while the fine siltstone component had the highest porosity mean (3.39%) and lower coefficient of variation (134.99%). the difference in the variation of coefficient proportions is related to the outlier ratios in each rock component. independently of both the rock types and the sedimentary structures, two clusters could be defined: one for the micro-porosity and one for the macro-porosity regimes. the former showed a continuous 3d spatial appearance, while the latter appeared in patches. these patches may also be connected, at least partly, to some local smectite aggregates. these clay minerals could lose their structured water content during vacuuming and swell when adsorbing water during sample saturation. in each rock type, the micro-porosity regime could be related to low-density rock fragments. the mean effective porosity of the micro-pore regime was about 0.02, which corresponds to the petrophysical core measurements. for the macro regimes, the average was 0.1 article history: manuscript received december 12, 2020 revised manuscript accepted july 05, 2021 available online october 13, 2021 keywords: boda claystone formation, ct, data mining, boolean function, authigenic mineral 1. introduction since its invention in the 1970s, x-ray computed tomography (ct) has spread and developed quickly, mostly stimulated by growing medical needs for diagnostic procedures and interventions. this technique which was initially meant to provide highresolution non-destructive 3d reconstructions of bones and soft tissues, eventually attracted interest from other domains such as industry and the geosciences (e.g., garvey & hanlon, 2002; louis et al., 2007). although computerized x-ray tomography (ct or cat scanning) has been used in the medical field for more than two decades (hounsfield, 1973; ledley et al., 1974), recently, it has been widely adopted in studying earth system processes such as earthquakes, orogeny, basin tectonics, or fluid circulation involving mechanisms down to the scale of individual grains (micrometre–millimetre). the ability of x-ray ct to monitor these mechanisms non-destructively and in three dimensions in the laboratory makes it an ideal tool for geoscientists (sutton et al., 2002). the x-ray ct has been used in different fields of geosciences, such as studying microstructural and rock physical properties of geological media, aiding and enhancing production in petroleum geology or assessing soil contamination or waste repository issues in environmental geology (van kaick & delorme 2005; cnudde et al. 2006). ct enables the analysis of the interior features of core samples, including bedding features, sedimentary structures, natural and coring-induced fractures, cement distribution, small-scale grain size variation, and density variation (coles et al., 1991; orsi et al., 1994; coles et al., 1998). this method has a wide application in geosciences, including analyses of the complex porosity and pore geometry of carbonate reservoirs (purcell et al., 2009), rock-fluid analysis (pyraknolte et al., 1997; purcell et al., 2009; wennberg et al., 2009), the performance of diverting agents in unconsolidated sandstones (vinegar and wellington, 1987; wellington & vinegar, 1987; ribeiro et al., 2007a), and many other topics. for instance, bonner et al. (1994) confirmed fluid migration in rocks by x-ray ct. verhelst et al. (1995), geiger et al. (2009) applied the technique to characterize small-scale heterogeneities in intact samples. schwartz et al. (1994) modeled the fluid flow in porous rocks by combining theoretical simulations with 3d imaging of the material studied. additionally, according to the considered rock type, accurate permeability and conductivity estimations are possible using ct (fredrich et al. 1993; coker et al. 1996; coles et al. 1998; arns et al. 2001, 2004). micro-ct (μct) systems offer a new depth of information that has not been available with conventional two-dimensional microscopy analysis. several studies have investigated the application of μct in mineral characterization, including pore analysis (yang et al., 1984; vinegar and wellington, 1987; withjack, 1987; hove et al., 1988; sprunt et al., 1991), g eo lo gi a c ro at ic a geologia croatica 74/3306 liberation and grain exposure (coles et al., 1991; spanne & rivers, 1987; nichols et al., 1989; jones et al., 1991; lontoc-roy et al., 2005; nahmani et al., 2005), crack and breakage analysis (conner et al., 1990; flannery et al., 1987), as well as mineral segmentation analysis (e.g., flannery et al., 1987). the main challenge in the full adoption of a µct system in these studies lies in the demanding computational processing of a large 3d dataset. additionally, since most of the µct analyses are based on the attenuation of the minerals, the presence of minerals with similar attenuations limits the capability of µct in mineral segmentation (guntoro et al., 2019). so, although the resolution of a medical ct is much lower than that of the µct, correspondence between the scales of medical ct measurements and petrophysical, sedimentological measurements applied to core samples makes it better suited for general core sample investigations (geiger et al., 2009). the present study focuses on quantifying and evaluating density and porosity characteristics of a core sample using medical ct scans at the scale of a hand-size specimen. a porosity dataset is derived for the identified depositional units from two ct scans at the same location, dry and saturated. this dataset provides porosity information at a much higher resolution, the scale of voxels, compared to traditional petrophysical measurements yielding data for the entire sample as a whole. coupled processing of information on rock-forming components with pore volume percentages on the same volume (voxel) has a major advantage over traditional petrophysical approaches. this approach makes a straight connection between the presence and share of rock-forming components and the expected variances of petrophysical properties. specific objectives could be addressed as follows: i) identification of the rock-forming components in the studied ct volumes. ii) calculation of the voxel porosity of the rock-type constituents. iii) analysis and visualisation of the 3d voxel porosity values for each rock component. iv) classification of the voxels into the optimal number of clusters where each cluster has a unique 3d pattern. v) analysis and visualisation of the 3d clusters of voxel-porosity for each rock type. vi) comparison of the mean voxel-porosity with other conventional porosity measurements. 2. ct principals and the ct technique applied 2.1. ct principals the theoretical foundations of computed tomography (ct) were established by cormack and hounsfield (1989). further technical developments in ct technology led to the introduction of new instruments ranging from spiral ct (1989), multi-slice ct, micro-ct, nano-ct (1998), to multi-slice ct with double x-ray tubes (garvey & hanlon 2002). the sample to be analyzed is placed within a gantry. x-ray radiation is transmitted through the sample in all directions of the points of a circle. gamma rays interact with the matter in four ways: raleigh scattering, photoelectric effect, compton effect, and pair generation (siegbahn, 1967). all these interactions are determined mainly by variations in the density and atomic composition of the highly collimated x-ray beam. detectors on the opposite side of the core measure the intensity of the transmitted beam. the x-ray source and/or detectors rotate or translate around the sample. a series of x-ray attenuation measurements are numerically reconstructed to give the spatial distribution of x-ray attenuation coefficients within the sample. the image resolution depends on the thickness of the x-ray beam, the number of detectors in the scanner, and the pixel array size used to reconstruct the image. x-ray beam thickness varies from about 2 mm to 10 mm. the ct measurements of geological samples enable the identification and evaluation of internal geological structures such as bedding planes, fractures and nodules, lithological changes, and bulk density. a combination of sequential x-y scans along the core axis can provide slab images or three-dimensional images of the core (attix, 1986; knoll, 2000). if the transfer of energy is constant, x-rays’ absorption depends only on the material they go through. for inhomogeneous samples including clastic sedimentary rocks, the attenuation coefficient has different values at different sample points (e.g., hounsfield, 1973, curry et al., 1990). the transmitted x-ray beam’s intensity is usually expressed as the hounsfield unit (its synonym is the ct number). each hounsfield unit (hu) represents a 0.1% change in density with respect to the calibration density scale. water is assigned a value of 0 hu, with air being equal to (-1000) hu and maximum attenuating materials measuring near 3,000 hu. images are then produced in a grayscale manner, with areas of low attenuation (low hu) being darker and high-attenuation regions (high hu) being brighter. with a given attenuation dataset, images can be further manipulated by changing the viewable window settings to accentuate specific contrast differences (wesolowski & lev 2005; bogner et al. 2003; földes et al. 2004; földes 2011). another essential feature of these types of analyses is the availability of a quantitative background dataset, which can be further evaluated both visually and by applying various statistical, or geostatistical approaches. 2.2. the ct technique applied ct measurements of the 1 m-long core sample were performed on a siemens emotion 6 medical scanner at the institute of diagnostic imaging and radiation oncology, university of kaposvar, hungary. the instrument operates at 120 kvp (peak kilovoltage), with 250 mas (milliampere-seconds) current, 1.0 s (sampling intervals). the lateral resolution was 0.1953 x 0.1953 mm2 with 1.25 mm of scan-layer thickness. the image reconstruction matrix was 512 x 512 pixels. the field of view (fov) was approx. 9.99 cm. the cleared images were exported as dcom images. this image format is a standard in medical applications and can be easily read by ‘classical’ 3d volume rendering software (e.g., voxler). the method of voxel-scale porosity determinations using ct scans was introduced by withjack (1988) and akin et al. (2000). at the university of kaposvár, földes, and his team introduced another dual-scanning approach for the evaluation of concrete elements (balázs et al., 2018). they have measured this core material by the same methods. firstly, they vacuumed the dry core material in a vacuuming tube. after six hours of vacuuming, they performed whole-core ct scans (dry condition). at the next step, they saturated the core material with water. after 1 hour of relaxation, they repeated the scanning process at the same position of the same measured slice (flooded or evacuated condition). they guaranteed that the dicom files were free of any artifacts and that during the second scans they measured the sample pixels as during the first scan. we have calculated the effective porosity values for each voxel of the scanned slices from both scans’ datasets using the calculation suggested by moss et al. (1990). 3. the general lithological characteristics of the study sample our study sample was taken from the boda claystone formation (bcf). the boda claystone formation represents the fill of a relag eologia c roatica abutaha et al.: evaluation of 3d small-scale lithological heterogeneities and pore distribution of the boda claystone formation using x-ray ... 307 tively small, continuously subsiding basin, which was one of the continental strike-slip and rift-related basins in the northern part of the internal variscan orogenic domain (vozárová et al., 2009). these upper permian terrestrial sequences are confined to the area of the mecsek hills in sw hungary (fig. 1a, haas & péró 2004; csontos & vörös, 2004). the bcf has two distribution areas in the western mecsek area: a perianticlinal structure and the so-called gorica block (fig. 1). continental sedimentation in the mecsek mts. was initiated in the early permian and lasted until the early triassic, yielding a 2000-4000m-thick continental clastic sequence (haas & péró 2004). the transitional and playa sediments of the bcf occur within the permian fluvial sequence. the lithology of the boda claystone can generally be subdivided into three major units. it starts with fine-grained sandstone beds at the base, overlain by albitic claystone/siltstone, and then continues with claystone, albitic clayey siltstone, and silty claystone with dolomite at the top (konrád, 1999). our study sample corresponds to a sample from the upper part of the ibafa-4 core sequences encompassing the depth interval from 602.41 to 603.46 m (fig. 2). at the request of geochem ltd., with the approval of the public limited company for radioactive waste management (puram), as part of an r&d project, dry and flooded ct measurements of 0.89 m and 10.54 m on ib-4 drill hole core material were carried out at the university of kaposvár. the location and the detailed core profile description are shown in figs. 1-2, respectively. in the referred sample, siltyclaystone is the dominant rock component. albite nests, vertical burrows, fractures with calcite fill, lamination, and bioturbation are all reported in the core description. since 1998, the public limited company for radioactive waste management (puram), as a hungarian governmental agency, has had the responsibility and monetary funds to coordinate the studies on the boda claystone formation as a potential high-level nuclear waste (hlw) disposal. in 2009, distinctive research was established to define intervals of ct numbers (hus) corresponding to constituents of the bcf. as a result of the cooperation between the university of szeged, geochem, and puram, the raw data sets were transferred to the university of szeged for further scientific research. defined ct intervals were as follows: detrital fragments (coarse siltstone): <2700 h.u, fine siltstone: 2700-3150 hu, claystone: 3150-3300 hu, calcite and /or dolomite: 3300-3600 h.u., and albite: >3600 hu. current work has considered these intervals to identify the rock-forming components of the core sample. 4. the general workflow of analysis all the ct scans were carefully processed to avoid artifacts such as beam hardening which occurs when the attenuation along a path passing through the centre of the object becomes larger than the attenuation along the path passing through the objects’ marginal parts. this happens because lower-energy x-rays are attenuated more readily than higher-energy x-rays; a polychromatic beam passing through an object preferentially loses the lower-energy parts of its spectrum. the result is a beam that has higher average energy than the incident beam, though diminished in overall intensity. this also means that, as the beam passes through an object, the effective attenuation coefficient of any material diminishes, thus making short ray paths proportionally more attenuating than long ray paths. in x-ray ct images of sufficiently attenuating material, this process generally manifests itself as an artificial darkening at the centre of long ray paths and a corresponding brightening near the edges. beam hardening can be a pernicious artifact because it changes the ct value of a material (or void) depending upon its location in an image. thus, to figure 1 a: distribution of the boda claystone formation sequences in the mecsek hills area (after haas & péró, 2004; konrad et al., 2010) with the location of the studied core site ibafa 4 (ib-4) marked by the red star at the left corner. g eo lo gi a c ro at ic a geologia croatica 74/3308 eliminate beam hardening, we remove the image’s outer edges and analyze only the centre. a 3d nearest neighbour algorithm was applied to build the 3d volumes of the scanned dry (vacuumed) and saturated core. this algorithm arranged the ct scans’ grid systems below one another in the actual stratigraphic position and fully honoured the measured ct numbers. from the dual ct scans, three parameters were available in each voxel: ct number of the dry (vacuumed) state, ct number of the saturated state, and the calculated effective porosity (fig. 2). the total number of voxels in each 3d model (dry core, saturated core, and effective porosity) was around 13 million. the workflow applied in this study relied on three fundamental scopes. the first one was identifying rock constituents according to the pre-classified ct intervals taken from the puram project. in this calibration phase, the suggested ct intervals of the rock components were visually compared with the dry hu patterns of the 3d ct volume; definable geometric characteristics (i.e., sedimentary structures) were also detected (“preprocessing” in fig.3). each voxel of the 3d ct volume was described with three variables: dry ct number, saturated ct number, and effective porosity. in our view, the dry and saturated ct numbers characterize the rock texture voxel by voxel, and the voxel porosity calfigure 2. rock column. g eologia c roatica abutaha et al.: evaluation of 3d small-scale lithological heterogeneities and pore distribution of the boda claystone formation using x-ray ... 309 culated in each voxel describes the petrophysical characters of each voxel partially. the spatial patterns of the voxels with similar effective porosity and textural characters (dry and saturated ct numbers) were divulged by a generalized k-means clustering algorithm of data-mining techniques (“data mining” in fig.3). in this process, we searched for the minimum number of “genetic groups”. classifying ct numbers into the minimum k number of disjoint clusters is an iterative method that assigns each point to the cluster whose centroid is the nearest. euclidean distance is generally considered to determine the distance between data points and the centroids. k-means clustering algorithm depends on the random choice of initial centroids. the computational complexity of k-means algorithms is very high, especially for large data sets. to determine the stable number of clusters, the k-fold cross-validation technique was used. each time, one of the k subsets is used as the test set/ validation set, and the other k-1 subsets are put together to form a training set. the error estimation is averaged over all k trials to get the total effectiveness of our model. the recent approach significantly reduces bias as we are using most of the data for fitting which significantly reduces variance. the final, third phase includes post-processing. the hu intervals of rock-type components coming from the first phase were used to build up the boolean lattices for each textural component. these boolean lattices were utilized to show the 3d spatial distributions of voxel-porosity by rock type (by multiplication of boolean lattices with voxel porosity) and the 3d distribution of porosity clusters by rock components (by multiplication of boolean lattices with clusters’ porosity). lastly, descriptive analyses were employed to estimate the statistical measure of central tendency and dispersion to organize the pores voxel information for each rock constituent in each hu 3d brick volume. a hypothesis test has been applied to evaluate and compare the implemented ct pore measurements with other conventional lab measurements, such as helium and mercury measurements. 5. results 5.1. ct characters of rock-forming components in the studied core after the ct numbers calibration and clearing beam hardening, the intervals from puram’s study were linked with the actual geological information of the core sample to visualize the 3d rock-forming components distribution. each 3d brick of the dry scans includes 5 rock constituents (fig. 4); detrital fragments shown as black (hu <=2700), fine siltstone in grey (2700 hu-3150 hu), claystone with green (3150 hu-3300 hu), dolomite, and calcite cement appears in light orange (3300 hu-3600 hu), and albite has a dark orange colour (hu>3600). a set of structures could also be identified, for instance; the upper first partition of the lithology profile in fig. 4 shows albite nests; it appears in the first 3d volume brick. the vertical burrows and calcite-filled fractures are dominant throughout the second and upper third profile’s partitions. the middle part of the bottom lithological profile shows some slumping surfaces. the bivariable histogram in fig 5a shows both saturated and dry core hu frequency observations. the midst bins intervals of the fine siltstone and claystone components (2700-3300 hu) pointed out the higher dry hu observations than saturated ones. in contrast, the intervals corresponding to carbonate and albite nests (>3300 hu) are characterized by higher hu values of the saturated sample. the coarse siltstone intervals (2700-2400) display, again, greater hu frequency observations in the saturated than in the dry core. fig. 5b shows box-plot charts of the hu values for the dry and saturated core sample. the dry core’s median is around 3100, while the saturated one is slightly lower than this. the first quartile (lowest 25%) of dry and saturated hu values are similar, at about 3200. the third quartiles (75% mark) are 3250 and 3000 hu for the dry and saturated core samples, respectively. the hu saturated chart’s minimum value is 2550, and the maximum is 3700. likewise, the minimum dry core hu value is 3175, and the maximum one is 3200. plenty of high and low hu value outliers can figure 3. the workflow. g eo lo gi a c ro at ic a geologia croatica 74/3310 be found in the saturated core sample volume; however, no outliers have been noticed in the dry one. the increased height of the box of the hu saturated core volume indicates the greater variation dispersed data, while the decreased height of the hu dry volume box indicates the less dispersed data. as shown by the extreme outliers’ values at the end of the two whiskers of the hu saturated core volume and the larger ranges, the overall spread indicates the wider distribution and more scattered points. 5.2. 3d spatial patterns within the core the first 3d volume profile’s bricks of the detrital fragments’ porosity in fig. 6, have 2881384 voxels; 21916 of these porosity valu es are greater than zero. the porosity mean of the terrigenous detrital fragments is 0.16%, with a high coefficient of variation value reaching 1039.39%. however, the fine siltstone component has 8,006,806 of no null voxel porosity value from the overall voxels number (8,655,548). its mean porosity is 3.39%, and the coefficient variation is 134.99%. the claystone component includes 6238159 porosity voxels; 5540873 are not null (porosity values >0). the porosity voxels mean and the coefficient of variation of the claystone component is 1.10% and 1.21%, respectively. the carbonate component consists of 4052229 voxels; 3500052 of the porosity voxels values are larger than zero. the mean of carbonate porosity voxel is 0.24%, with the second higher coefficient value of 458%. figure 4. rock-forming components. legend; d.f.=detrital fragments, f.s=fine siltstone, cl=claystone, car.=carbonate and dolomite cement, ab= albite nests. g eologia c roatica abutaha et al.: evaluation of 3d small-scale lithological heterogeneities and pore distribution of the boda claystone formation using x-ray ... 311 the albite nests component has 2857049 voxels; only 177 of them have no null porosity values. the mean porosity voxels of the albite nests are 2.14%. and the coefficient of variation is 77.39%. further details of porosity basic statistical properties by rock constituents are illustrated in table 1. the conspicuous sedimentary structures in the ct images; fractures, and convolute deformation are marked in fig. 7a fracture in fig. 7a shows high-density contrast between the calcite’s infilling material and surrounding sediment. it is recognized as dark parts in the porosity ct image (fig. 7b). conversely, the convolute lamination textural pattern has almost been preserved in the ct porosity scan image (fig. 7c-d). textural variables of the hu of the saturated core (fld) and hu of the dry core, as well as the porosity variable for petrophysical properties, were utilized to detect textural and petrophysical voxel characteristics using the genetic groups’ technique. our work deals with chebyshev distances; 10 (v-value) cross-validation and 20 iterations were applied in each approximation. there were about 13 288 316 training cases (fig. 8). the initial result of clustering was 6 clusters, k=6 (fig. 8a). however, the arithmetic means of porosity manifest that clusters 1, 3, and 6 are quite similar; clusters 5 and 2 are also comparable. therefore, the maximum number of porosity clusters for the next run was suggested to be 3, and the minimum number of clusters premised to be 2, k=3 (fig. 8b). eventually, two clusters were demonstrated for genetic heterogeneity of the porosity values greater than zero, k=2 (fig. 8c). to compare the spread and centers of porosity values larger than zero for the two resultant clusters, the box-plot chart was used (fig. 9). the median of cluster 1 appears to be approximately 10%, whereas cluster 2 has a median of around 2.5%. 25% of cluster 1 porosity values are less than 8%. hence, 75% of the porosity valu es in cluster 1 are larger than 8% and lower than 19% (iqr range=11%). in comparison, 25% of porosity values in cluster 2 are less than 1%. thus, 75% of voxel porosity in cluster 2 is higher than 1% and lower than 8% (iqr range=7%). therefore, the above two clusters could be presented by their average porosity values; matrix porosity with an average of 2.5%, and macro-pore porosity with a 10% average. the porosity outlier values beyond the upper whisker in fig. 9, are an exclusive macro-pores cluster note. the outlier values are extended from 18% (over the maximum value) up to 37% (extreme outlier). fig. 10 shows the 3d distributions of the three porosity clusters for each rock constituent. clusters are identified in three colours; black for no porosity, green for cluster 1 (matrix porosity cluster), and cluster 2 has a red colour (macro-porosity cluster). the detrital fragments component shows almost a mixture of the three colours. the cluster of no porosity is prevalent in the fine siltstone component, while clusters 1 and cluster 2 are less abundant. the pervasive cluster in the claystone component is the no-porosity cluster with the subdued appearance of cluster 1. carbonate/dolomite and albite constituents show mostly no-porosity clusters. the rock constituents ratios versus porosity clusters distribution are summarized in fig. 11 which shows that each porosity cluster has different rock-forming components in definite ratios. figure 5. histograms of the saturated and dry samples (a) and the corresponding box-plots (b) table 1. basic statistical properties of voxel porosity by rock constituents. no. of voxels no. of no-null voxels mean of voxel porosity % md. of voxel porosity % min. of voxel porosity % max. of voxel porosity % coefficient of variation % min. voxel porosity of outliers % ro ck s co ns tit ue nt s detrital fragments 2881384 21916 0.16 0.0006 0.0004 35.74 1039.39 32.33 fine siltstone 8655548 8006806 3.39 0.52 0.0007 33.11 134.99 15.14 claystone 6238159 5540873 1.1 0.0009 0.0005 23.08 221.12 1.21 carbonate 4052229 3500052 0.24 0.0008 0.0006 19.24 457.34 2.10e-12 albite nests 2857049 117 2.14 1.78 0.055 7.54 77.39 5.73 g eo lo gi a c ro at ic a geologia croatica 74/3312 the no-porosity cluster shows a very dense texture, including a variety of rock components; it consists of about 19% fine siltstone, 23% claystone, 13% carbonate, 0.16% albite, and is almost lacking detrital fragments. compared with cluster 1, the fine siltstone forms around 20%, claystone is decreased to 8.44%. the carbonate content is also reduced to 1.66%, with no albite, and the detrital fragments component appears as 0.05%. cluster 2 involves around 12% fine siltstone, 2.33% claystone, 0.27% carbonate, and no albite. the detrital fragment increases to 0.23%. the total ratios of voxel porosity in each rock component over the three clusters are as follows: 0.29% detrital fragments, 50.74% fine siltstone, around 34% claystone, and 15% carbonate. albite has the lowest porosity ratio summation along with three clusters at 0.17% (fig. 11). table 2 shows the means of voxel porosity for three clusters; the matrix cluster has a 3.39 mean value, whereas the macropores cluster has a 10.77 mean value and zero for the no-porosity cluster. ratios of voxel-porosity of the three clusters have also been calculated and listed in table 2; the matrix cluster forms 30.37%, the macro-pores cluster accounts for 14.65%, and the no-porosity cluster represents around 55% of the gross clusters’ ratios. the weighted porosity average of matrix and macro clusters in the full volume was calculated by multiplying the total voxel figure 6. porosity of the rock-forming components. g eologia c roatica abutaha et al.: evaluation of 3d small-scale lithological heterogeneities and pore distribution of the boda claystone formation using x-ray ... 313 figure 7. fracture and convolute structures in the h.u. image and voxel-porosity slices. red borders in a-b show a calcite filled fracture, whereas red arrows in c-d illustrate an example of a convolute structure in the detrital fragments and siltstone constituents. table 2. comparison of mean porosity coming from ct scans with routine porosity measurements. mean of voxel porosity where poro.>0 (c1) no of voxels (%) c2 the ratio of voxels (%) c3 porosity in the full volume (%) from ct scans (c1*c3/100) for macro and matrix heporosity hg-porosity matrix 3.3 4035718 30.37 1.002 1.59 macro-pores 10.77 1946183 14.65 1.578 matrix and macro 5.72 5981901 45.02 2.575(*) 2.51 2.02 no-porosity 0 7306394 54.98 0 (*) weighted average g eo lo gi a c ro at ic a geologia croatica 74/3314 count (c1) for each cluster, by the ratio of voxel porosity of these clusters (c3). results were arithmetically adding and resulted in a value of 2.58% (table 1). the final average number reflects each observation’s relative importance and is accordingly more descriptive than a simple average. in comparison, the he porosimetry measurements show quite close value for the calculated porosity mean of the ct scans image (2.51%) while the hg measurement given smaller porosity mean values at 2.02%. more detailed data can be seen in table 2. the hg and he measurements were carried out in the geochem laboratory and the results published in fedor et al., 2018. 6. discussion the various illite and illite/smectite mixed assemblages represent the dominant clay minerals of the boda claystone formation (németh & máthé, 2016). clay minerals are present in the form of a detrital matrix or as part of rock fragments known as „allogenic clays” as well as replacements (by alterations) or cement, called authigenic clays. authigenic clay minerals impact formation porosity to a greater extent because of their direct vulnerability to pore fluids compared to detrital clay minerals, which are tightly packed in the rock matrix. authigenic clay minerals occur as pore linings, pore fillings, pseudomorphic replacements, and fracture fillings (e.g. ahmad et al., 2018). the reactions of water with these clay minerals (during the core sample’s saturation phase) significantly impacted the petrophysical properties. these reactions cause dissolution, precipitation, plugging, clay swelling, and migration of fine particles. the porous medium of siltstone and detrital fragments can be represented as a network, consisting of pores connected by throats or narrower pore channels. the presence of clay minerals as a dispersed matrix in the pore space reduces the pore throat size and overall permeability due to the release of clay particles from pore walls and their subsequent redeposition downstream in the pore throats, which presumably results in plugging of the pore throats (al-yaseri et al., 2015; hayatdavoudi and ghalambor 1996; simon and anderson 1990; zhou et al. 1995). the variations of the hu observations in fig. 5a could be assigned to the release of fine grains of non-clay minerals (such as carbonate or albite cement) and clay particles (such as illite) from pore filling and subsequent redeposition downstream in pore throats of the fine siltstone component, otherwise dispersed in the original claystone structure. that could explain the relative decrease of the claystone and fine siltstone hu observations in fig. 5a. simultaneously, the migration of fines from the detrital figure 8. sequence clustering of voxel-porosity values. figure 9. box-plot of porosity by clusters; cluster 1 represents the macro-pores cluster, and cluster 2 refers to the matrix cluster. g eologia c roatica abutaha et al.: evaluation of 3d small-scale lithological heterogeneities and pore distribution of the boda claystone formation using x-ray ... 315 fragments within porous media could be seemingly the source of lesser representation of dispersed material and increased values of the saturated hu observations in fig. 5a. swelling clays, such as smectite and mixed-layer clays, first expand under favourable ionic conditions and then disintegrate and migrate. smectites can be significantly affected by minor changes in temperature and water vapour pressure, leading to changes in rock strength, porosity, and permeability. the reactions of concern include (1) reversible collapse/expansion of the smectite layers due to loss/gain of interlayer water; (2) irreversible collapse due to loss of interlayer water and migration of interlayer cations into the 2:1 silicate layers; (3) irreversible reduction of the osmotic swelling ability through reaction in a steam atmosphere; and (4) inhomogeneous transformation of the smectite into an interstratified illite/smectite (pusch & karnland, 1996). accordingly, three scenarios could be proposed to interpret outliers in fig. 5b; non-swelling clays e.g., kaolinites and illites, tend to detach from the rock surface, migrating (non-clay) fine particles e.g., cement, and smectite might swell and become free to move. these suggestions could explain the full or partial plugging of the pore throats and the increase of the minimum hu values outlier. beyond that, collapsing of smectite, through one of the four above points, could lead to the adsorption of less water during the saturation phase, which together with particles refigure 10. porosity clusters by rock-forming components. g eo lo gi a c ro at ic a geologia croatica 74/3316 leasing from the detrital deposit structure could also create additional pore space. appropriately, the maximum hu outlier in fig. 5b and fig. 9 would result. the exceptionally high coefficient of variation percentage of the detrital terrigenous fragments constituent (1039.39%) in table 1, reflects the high ratio of the standard deviation compared to the mean. the more extreme the outlier (32.33%), the more the standard deviation is affected, and the greater coefficient of variation arises. the large proportion of the minimum outlier probably results from migrating non-clay and/or non-swelling particles from pore walls during the flooding process. it could occur due to migration of smectite with the fluid flowing through the porous formation. in contrast, the fine siltstone coefficient of variation ratio is way lower than the detrital fragments variation (134.99%). this is relevant to the higher mean value (3.39%) and lower minimum porosity of outliers (15.14%). it could be said therefore that the lower the outlier ratio, the less the standard deviation is affected, and the smaller proportion of the variation coefficient produced. it is quite appropriate reliable to recall the throat plugging proposal here. the low porosity outlier proportions of claystone, carbo nate, and albite seem not to affect the coefficient variation ratios. relative high coefficients of variations have resulted from high standard deviation values comparable with low mean values. it is worthy to note that since these three last components are classified as filling material components or dispersible particles, the low minimum porosity outlier ratios are to be expected. the descending porosity ratio of claystone accompanied by the lower carbonate porosity ratio over the three clusters in fig. 11 seem to play a significant role in the porosity distribution of clusters. comparing the claystone ratios across the three clusters; the no-porosity cluster has an extraordinary claystone proportion (around 23%), while the matrix and macro clusters show lower claystone ratios at 8.44% and 0.27%, respectively. correspondingly, the carbonate cement has a high proportion in the no-porosity cluster (about 19%), and it decreases in both the matrix (1.66%) and macro-pore (0.27%) clusters. this observation suggests the higher the claystone and carbonate ratios, the lower the porosity proportions. it is also highly expected to find authigenic clay in the claystone component of the no-porosity cluster. albite presence leads to pores becoming fully plugged in the no-porosity cluster (0.16%), whereas in the macro-pores cluster, albite is absent, and the detrital fragments occur instead (0.23%). it could be expected that pore spaces (macro-pores) might be created within the portion of the detrital fragment because of the larger relative grain size. claystone and carbonate components are reasonably consistent; reducing claystone across the three clusters is associated with a decreasing carbonate ratio while albite would not produce a similar result. the difference of coincidence between these three components is related to the bcf diagenetic phases. the weathered residue of the basement mafic rocks accounts for authigenic deposits in the bcf playa basin. albite cement (porefilling and interstitial) is formed by adding na ions from an alkaline brine and evaporites to the boda claystone sediments. the formation of albite was the reason for the depletion of na ions in the claystone. ca and k-enriched waters reacted with smectite and kaolinite to yield k-rich illite with precipitation of ca in carbonate cement (varga et al., 2005). the chi-square independence test emphasized that the clusters are related to their rock-type constituents at the 95% confidence level for a particular case. the lambda and pearson’s r tests were applied to detect the association between clusters and rock-type variables. based upon the lambda value (0.0856), the reduction in error when a cluster is used to predict rock components is 8.56%. also, pearson’s correlation shows a significant association between clusters and rock components at the 95% confidence level. the r-value was around 0.4. the measurement protocol of the ct-laboratory allows a maximum of 10 hu absolute value noise. in the studied core, only figure 11. crosstabulation chart table of rock components and clusters. g eologia c roatica abutaha et al.: evaluation of 3d small-scale lithological heterogeneities and pore distribution of the boda claystone formation using x-ray ... 317 1.6% of the total number of voxels showed that the difference between the saturated and dry hus was less than 10 hu. table 3 shows the statistical characteristics of the density contrast between the dry and saturated scans and the calculated voxel porosity of this noisy-critical subset. the average mean of the difference between the saturated and dry hu values (<10 hu) was around 5. it can also be seen that the voxel porosity varies between 0.028 % and 0.40 % in this subset. the corresponding mean voxel-porosity is 0.17%. if we suppose that all hu contrast measured in this critical subgroup is noise, then the average voxel-porosity calculated for the whole core, 2.51%, can be decreased by a minimum of 0.028% porosity and a maximum of 0.40% porosity. so the average voxel porosity corrected by the expected noise may vary between 2.11% and 2.34%. by neglecting the noise effect, the difference between the ct porosity scanned volume, and the mercury porosity means value in table 2 is caused due to the limitation of mercury measurements. small pore volumes are usually not accessed by the mercury, even at the highest pressures. unreachable minute pores in the hg method reduce the porosity mean to 2.02%, while the mean porosity of the ct scans is 2.57%. however, the helium molecule’s small size enables its entrance into the narrow pore structures and penetration into even the smallest pores. so, it gives a similar value for the porosity mean as the scanned ct volume (2.51%). the hypothesis testing has been executed to determine which laboratory pore measurements should be considered and which should be discarded. the null hypothesis assumed that the difference between the mean ct and hg porosity values are equal to zero. as a result, the null hypothesis is rejected at the 95% confidence level, and the confidence interval shows that the values of (ct mean= hg mean) supported by data fall between (0.272 and 0.827). in the mean ct and he values comparison, the null hypothesis could not be rejected since the confidence interval supported by the data falls between (-0.217 and 0.337). from this perspective, only the he measurement could be considered reliable. 7. summary this work proposed a straightforward procedure to estimate the rocks’ petrophysical properties of a selected core sample volume. the dual ct scans’ parameters were analyzed to establish the direct relationship between the rock-forming components and the petrophysical properties. voxel-porosity of the rock constituents was successfully classified into three major clusters based on porosity and textural patterns. two major pore regimes are demonstrated by the heterogeneous spatial distribution of pore volume; matrix porosity and vug porosity. micropores from the matrix cluster occupy a significant proportion of the total porosity. authigenic minerals play an influential role in decreasing the pore volume and plugging the pore throats via the swelling and migration of fine particles. obtained mean porosity value corresponds well with the mean porosity measured by helium porosimetry. the discrepancy between the mean ct porosity value and mean porosity value obtained by hg measurements can be assigned to the limitations of the laboratory method with respect to inaccessibility of small pores to mercury penetration. cementation and the authigenic clay content are considered to be the main pore volume-controlling factors of the bcf core sample. however, sedimentary structures, i.e., convolute structures, could also be a significant porosity-improving factor. acknowledgement the authors would like to acknowledge the public limited company for radioactive waste management (puram) to permit the university of szeged to use their data sets in its scientific research work. this research is sponsored by; interdisciplinary excellence centre, institute of geography and earth sciences, long environmental changes research team, grants 20391-3/2018/ fekustrat and ginop-2.3.2-15-201600009 ‘icer’ of the european union and the state of hungary, ministry of human capacities. mecsekérc ltd had financed the measurements. cofinancing was provided by the european regional development fund. references ahmad, k.m., kristály, f. & turzo, z. (2018): effects of clay mineral and physico-chemical variables on sandstone rock permeability.– j oil gas petrochem sci., 1/1, 18–26. doi:10.30881/jogps.00006 akin, s., demiral, b. & okandan, e. (1966): a novel method of porosity measurement utilizing computerized tomography.– in situ, 20 /4, 347–365. al-yaseri, a.z., lebedev, m., vogt s.j., johns, m.l., barifcani, a. & iglauer, s. (2015): pore-scale analysis of formation damage in bentheimer sandstone with in-situ nmr and micro-computed tomography experiments.– j. petrol. sci., 129, 48–57. doi: 10.1016/j.petrol.2015.01.018 arns, c.h., knackstedt, m.a., pinczewski, w.v. & lindquist, w.b. (2001): accurate estimation of transport properties from microtomographic images.–geophysical research letters, 28, 3361–3364. doi: 10.1029/2001gl012987 attix, f.h. (1986): introduction to radiological physics and radiation dosimetry.– wiley-vch. doi: 10.1002/9783527617135 balázs, gy.l., lublóy, é. & földes, t. (2018): evaluation of concrete elements with x-ray computed tomography.– j. mater. civ. eng., 30/9, 06018010. doi: 10.1061/(asce)mt.1943-5533.0002389 bogner, p.t., földes, f. & závoda, i.r. (2003): application of ctand mr in the carbon hydrogen research.– j. hongroise radiology, 77/5, 231–237. bonner, b.p., roberts, j.j. & schneberk, d.j. (1994): determining water content and distribution in reservoir graywacke from the northeast geysers with x-ray computed tomography.– geotherm. resource council trans, 18, 305-310. cnudde, v., masschaele, b., dierick, m., vlassenbroeck, j., van hoorebeke, l. & jacobs, p. (2006): recent progress in x-ray ct as a geosciences tool.– applied geochemistry, 21/5, 826–832. doi: 10.1016/j.apgeochem.2006.02.010 coker, d.a., torquato, s. & dunsmuir, j.h. (1996): morphology and physical properties of fontainebleau sandstone via a tomographic analysis.– journal of geophysical research, 101, 17497–17506. doi: 10.1029/96jb00811 coles, m.e., hazlett, r.d., spanne, p., soll, w.e., muegge, e.l. & jones, k.w. (1998): pore level imaging of fluid transport using synchrotron x-ray microtomography.– journal of petroleum science and engineering,19/1–2, 55–63. doi: 10.1016/s0920-4105(97)00035-1 coles, m.e., muegge, e.l. & sprunt, e.s. (1991): applications of cat scanning for oil and gas-production research.– ieee transactions on nuclear science, 38/2, 510–515. doi: 10.1109/nssmic.1990.693464 cormack, a.m. & hounsfield g.n. (1989): physiology or medicine 1979: press release. accessed april 21, 2018.https://www.nobelprize.org/nobel_prizes/medicine/laureates/1979/press.html. csontos, l. & vörös, a. (2004): mesozoic plate tectonic reconstruction of the carpathian region.– palaeogeography, palaeoclimatology, palaeoecology, 210/1, 1–56. doi: 10.1016/j.palaeo.2004.02.033 flannery, b.p., deckman, h.w., roberge, w.g. & d’amico, k.l. (1987): three-dimensional x-ray microtomography.– science, 237, 1439–1444. doi: 10.1126/science.237.4821.1439 table 3. statistical characteristics of the density contrast between the dry and saturated scans and the calculated voxel porosity of the 10 hu absolute value noise. valid n mean min. max. std.dev fld-dry (hu) 246187 5.501 1 10 2.869 porosity (%) 246187 0.175 0.028 0.4 0.091 g eo lo gi a c ro at ic a geologia croatica 74/3318 fedor, f., máthé, z., ács, p. & koroncz, p. (2018): new results of boda claystone research genesis, mineralogy, geochemistry, petrophysics.– in: norris, s., neeft, e.a.c. & van geet, m. (eds.): multiple roles of clays in radioactive waste confinement. geological society, london, special publications, 482, doi: 10.1144/sp482.13 földes, t. (2011): integrated processing based on ct measurement.– j. news geom., 1, 23–41. földes, t.b., kiss, g., árgyelán, p., bogner, i. & repa, k. hips. (2004): application of medical computer tomography measurements in 3d reservoir chara cterization.– acta geologica hungarica, 47/1, 63–73. doi: 10.1556/ ageol.47.2004.1.5. fredrich, j.t., greaves, r.h. & martin, j.w. (1993): pore geometry and transport properties of fontainebleau sandstone.– international journal of rock mechanics & mining sciences & geomechanics abstracts, 30, 691–697. doi: 10.1016/0148-9062(93)90007-z garvey, c.j. & hanlon, r. (2002): computed tomography in clinical practice.– british med. j., 324 /7345, 1077–1080. doi: 10.1136/bmj.324.7345.1077 geiger, j., hunyadfalvi, z. & bogner, p. (2009): analysis of small-scale heterogeneity in clastic rocks by using computerized x-ray tomography (ct).– eng. geol., 103, 112–118. doi: 10.1016/j.enggeo.2008.06.011 guntoro, p.i., ghorbani, y., koch, p.h. & rosenkranz, j. (2019): x-ray microcomputed tomography (µct) for mineral characterization; a review of data analysis methods.– minerals, 9, 183 p. doi: 10.3390/min9030183 haas, j. & péró, c.s. (2004): mesozoic evolution of the tisza mega-unit.– international journal of earth sciences, 93, 297–313. hayatdavoudi, a. & ghalambor, a. (1996): controlling formation damage caused by kaolinite clay minerals: part i.– in: spe formation damage control symposium, society of petroleum engineers, spe-31118-ms. doi: 10.2118/31118ms hounsfield, g.n. (1973): computerized transverse axial scanning (tomography). 1. description of system.– br. j. radiol., 46/552, 1016–1022. doi: 10.1259/00071285-46-552-1016 hove, a.o., nilsen, v. & leknes. j. (1988): visualization of xanthan flood behavior in core samples by means of x-ray tomography.– spejdoe, 17342. jones, k.w., spanne, p., webb, s.w., conner, w.c., beyerlein. r.a., reagan. w.j. & dautzenberg, f.m. (1991): catalyst analysis using synchrotron x-ray microscopy.– nuc. inst. meth. phy. res., 56–57, 427–432. doi: 10.1016/0168-583x(91)96063-q knoll, g.f. (2000): radiation detection and measurement.– j. wiley & sons., 816 p. koch, a., raven, c., spanne, p. & snigireva, a. (1998); x-ray imaging with submicrometer resolution employing transparent luminescent screens.– journal of the optical society of america. a, optics and image science, 15/7, 1940–1951. konrád, g.y. (1999): the boda claystone formation. the geology of today for tomorrow.– excursion guide book (a satellite conference of the world conference of science, budapest), 65–75. konrád, g.y., sebe, k., halász, a. & babinszki, e. (2010): sedimentology of a permian playa lake: the boda claystone formation, hungary.– geologos, 16, 27–41. doi: 10.2478/v10118-010-0002-1. ledley, r.s., chiro, g.d., luessenhop, a.j. & twigg, h.l. (1974): computerized transaxial x-ray tomography of the human body.– science, 186, 207–212. lontoc-roy, m., dutilleul, p., prasher, s.o., han, l.w. & smith, d.l. (2005): computed tomography scanning for three-dimensional imaging and complexity analysis of developing root systems.– canadian journal of botany, 83, 1434–1442. doi: 10.1139/b05-118 louis, l., wong, t. f. & baud, p. (2007): imaging strain localization by x-ray radiography and digital image correlation: deformation bands in rothbach sandstone. – journal of structural geology, 29/1, 129–140. doi: 10.1016/j.jsg.2006.07.015 moss, r.m., pepin, g.p. & davis, l.a. (1990): direct measurement of the constituent porosities in a dual porosity matrix.– sca conference, 9003. nahmani, j., capowiez, y. & lavelle, p. (2005): effects of metal pollution on soil macroinvertebrate burrow systems.– biology and fertility of soils, 42, 31–39. doi: 10.1007/s00374-005-0865-4 németh, t. & máthé, z. (2016): clay mineralogy of the boda claystone formation (mecsek mts., s.w. hungary).– open geoscience, 8, 259–274. doi: 10.1515/geo2016-0024. nichols, m.c., kinney, j.h., johnson, q.c., saroyan, r.a., bonse, u., nusshardt. r. & pahl. r. (1989): synchrotron microtomography of supported catalysts.– rev. sci. inst., 60/7, 2475. doi: 10.1063/1.1140703 purcell, c., harbert, w., soong, y., mclendon, tr, haljasmaa, iv, mcintyre, d. & jikich, j. (2009): velocity measurements in reservoir rock samples from the sacroc unit using various pore fluids, and integration into a seismic survey taken before and after a co2 sequestration flood.– in: gale, j., herzog, h. & braitsch, j. (eds.): energy procedia: greenhouse gas control technologies, 9, elsevier science, amsterdam, 2323–2331. doi: 10.1016/j.egypro.2009.01.302 pusch, r. & karnland, o. (1996): physico/chemical stability of smectite clays.– engineering geology, 41/1–4, 73–85. doi: 10.1016/0013-7952(95)00027-5. pyraknolte, l.j., montemagno, c.d. & nolte, d.d. (1997): volumetric ima ging of aperture distributions in connected fracture networks.– geophysical research letters, 24/18, 2343–2346. ribeiro, j.l.b., lopes, r.t., anjos, m.j., queiroz neto, j.c., bianco, l.c.b., campos, e.f. & d’almeida, a.r. (2007a): study of performance with diverting agents in formation damage and return of permeability for unconsolidated sandstones using computed tomography.– in: 2006 ieee nuclear science symposium conference record. ieee, san diego, ca, 7,7p. doi: 10.1109/nssmic.2006.356039 schwartz, m.f., saffran, e.m., fink, r.b., myers, j.l. & martin, n. (1994): mapping therapy: a treatment programme for agrammatism.– aphasiology, 8/1, 19–54. doi: 10.1080/02687039408248639. siegbahn, k. (1967): alpha, beta, and gamma ray spectroscopy.– north-holland, amsterdam. simon, d. & anderson, m. (1990): stability of clay minerals in acid.– in: spe formation damage control symposium. society of petroleum engineers, spe-19422ms, doi: 10.2118/19422-ms spanne, p. & rivers, m. (1987): computerized microtomography using synchrotron radiation from the nsls.– nucl. instr. meth. phy. res., 24–25, 1063, 67p. doi: 10.1016/s0168-583x(87)80312-9 sprunt, e.s., desai, k.p., coles, m.e., davis. r.m. & muegge, el (1991): cat scan monitored electrical resistivity measurements show problems achieving homogeneous saturation.– soc pet. eng., 21433. sutton, s.r., bertsch, p.m., newville, m., rivers, m., lanzirotti, a. & eng, p. (2002): microfluorescence and microtomography analyses of heterogeneous earth and environmental materials.– in: fenter, p., rivers, m., sturchio, n. & sutton, s. (eds.): applications of synchrotron radiation in low-temperature geochemistry and environmental sciences. reviews in mineralogy and geochemistry, 49, 429–483. doi: 10.1515/9781501508882-014 van kaick, g. & delorme, s. (2005): computed tomography in various fields outside medicine.– european radiology, 15/s4, d74–d81. 10.1007/s10406-0050138-1 varga, a.r., szakmány, gy., raucsik, b. & máthé, z. (2005): chemical composition, provenance and early diagenetic processes of playa lake deposits from the boda siltstone formation (upper permian), sw hungary.– acta geologica hungarica, 48/1, 49–68. doi: 10.1556/ageol.48.2005.1.2 verhelst, f., vervoort, a., de bosscher, p.h. & marchal, g. (1995): xray computerized tomography: determination of heterogeneities in rock samples.– in: proc. 8th int. congress of rock mechanics, isrm/balkema, 1,105–108. vinegar, h.j. & wellington, s.l. (1987): tomographic imaging of three-phase flow experiments.– the review of scientific instruments, 58/1, 96–107. doi: 10.1063/1.1139522 vozárová, a., ebner, f., kovács, s., kräutner, h-g., szederkényi, t., kristić, b., sremac, j., aljinovič, d., novak, m. & skaberne, d. (2009): late variscan (carboniferous to permian) environments in the circum pannonian region.– geologica carpathica, 60, 71–104. wennberg, o.p., rennan, l. & basquet, r. (2009): computed tomography scan imaging of natural open fractures in a porous rock; geometry and fluid flow.– geophysical prospecting, 57 /2, 239–249. doi: 10.1111/j.1365-2478.2009.00784.x wesolowski, j.r. & h.m. lev. (2005): ct: history, technology, and clinical aspects.– seminars in ultrasound, ct and mri, 26/6, 376–379. doi: 10.1053/j. sult.2005.07.007 withjack, e.m. (1988): computed tomography for rock property determination and fluid flow visualization.– spe formation evaluation, 3/4, 696–704. doi: 10.2118/16951-pa yang, y., ayral, s. & gryte, c.c. (1984): computer-assisted tomography for the observation of oil displacement in porous media.– soc. pet. eng. j., 24/1, 53–55. doi: 10.2118/11758-pa zhou, z., gunter, w. & jonasson, r. (1995): controlling formation damage using clay stabilizers: a review.– in: annual technical meeting. petroleum society of canada, petsoc-95-71. doi: 10.2118/95-71 2022 | 75/special issue | 317–334 | 5 figs. | 2 appendix tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction and background geographically and politically, the adria region includes the area of the western balkans, i.e., albania (alb), bosnia and herzegovina (bih), croatia (hrv), montenegro (mne), north macedonia (mkd), and serbia (srb). in the early neolithic period, the adria region was a centre of mining and metallurgical activities due to its richness in copper ore minerals such as malachite and azurite (radivojević et al. 2010). mining and smelting activities in the roman period included base metals such as copper, gold, silver, lead, and zinc, while today numerous metallic and non-metallic raw materials are mined and processed in the region (reichl & schatz, 2021). 1.1. raw material potential the adria region mainly comprises the dinarides, the northwesternmost hellenides, and the vardar zone, which host palaeozoic to neogene external and internal units (the high karst and prekarst units, variscan basement units with the surrounding bosnian flysch, the western vardar ophiolite unit, and the sava suture zone) and ore deposits associated with various stages of the alpine wilson cycle (palinkaš et al., 2008; pamić et al., 1998). the predominant ore-productive phases are the following: the future of mining in the adria region: current status, swot and gap analysis of the mineral sector sibila borojević šoštarić1, stavroula giannakopoulou2, katerina adam2 and marta mileusnić1,* 1 university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, hr-10000 zg; (sibila.borojevic-sostaric@rgn.unizg.hr; *corresponding author: marta.mileusnic@rgn.unizg.hr) 2 national technical university of athens, school of mining & metallurgical engineering, 9, iroon polytechniou str, gr-157 80 athens; (gianstav@metal.ntua.gr; katadam@metal.ntua.gr) doi: 10.4154/gc.2022.26 abstract the adria region which includes the countries of: albania, bosnia and herzegovina, croatia, montenegro, north macedonia, and serbia, and corresponds to the dinarides, northwesternmost hellenides, and the vardar zone, has a long history of mining. here, the main strengths and challenges of the mineral sector of the adria region were assessed using the following methodology: (1) presentation of the current status of mineral exploration and exploitation, (2) swot (strengths, weaknesses, opportunities, threats) analysis on parameters including geological potential, economic environment, legal and regulatory framework, innovation and technology framework, environmental protection and land use planning, governmental and social potential, human resources and educational potential, (3) gap analysis, and (4) integration of the results obtained in the development of a roadmap for the actions required to promote investments in the mineral sector in the adria region. the main strengths of the regional mineral sector include the significant mineral potential due to a favourable geological setting, significant reserves, a long mining tradition, and active exploration areas, as well as a significant number of active and abundant mines and the availability of secondary raw materials. nevertheless, there are many challenges that the mineral sector faces, such as difficulties in ensuring social acceptance, a lack of new exploration campaigns in many areas, estimation of resources or reserves that do not follow international codes and standards, regulations related to environmental issues in the mineral sector of adria countries that do not comply with european legislation, and the limited availability of qualified technical, scientific and managerial personnel involved in the whole mineral cycle. therefore, actions and measures such as awareness campaigns to highlight the significance of raw materials in the sustainable development of the region, further exploration, reserves calculation in alignment with internationally recognized codes, harmonization with spatial plans, and reforms to attract investors and capacity building programs should be taken for further development of the adria region’s mineral sector in a sustainable manner. (1) permian units related to early intracontinental rifting hosting hydrothermal siderite-baryte polysulfide deposits, epigenetic sedimentary uranium deposits, red bed-type, sabkha-type copper and barite deposits and evaporites (palinkaš et al., 2008), that are widespread mainly in the northern part of the dinarides (croatia, bosnia and herzegovina, and partly albania). ongoing exploitation in the region is related to (a) evaporites (croatia, bosnia and herzegovina, and albania) and (b) gossans developed over primary siderite-polysulfide deposits (bosnia and herzegovina). (2) advanced triassic rifting with mn-fe-sedex and hydrothermal iron-polysulfide-barite-mercury deposits with ongoing production/project activities in manganese and antimony deposits in bosnia and herzegovina. (3) jurassic oceanization associated with chromite, titanomagnetite, the platinum group elements (pges), cu hydrothermal and magnesite deposits in the upper part of the ophiolite sequences in the ophiolite zone of the inner dinarides hellenides and coeval bauxites on the high karst and pre-karst units. ongoing geological prospecting and exploitation are focused on (a) copper, sometimes associated with pb, zn, au, ag, se (albania; milushi, 2015; horn et al., 2021), (b) bauxite, occasionally enriched with titanium and rare earth elements (rees) (croatia, bosnia and herzegovina, montenegro, albania; tomašić et al, article history: manuscript received december 31, 2021 revised manuscript accepted july 01, 2022 available online october 17, 2022 keywords: raw materials potential, exploration and exploitation status, swot analysis, gap analysis, adria region mailto:sibila.borojevic-sostaric@rgn.unizg.hr mailto:gianstav@metal.ntua.gr g eo lo gi a c ro at ic a geologia croatica 75/special issue 318 2019; radusinović & papadopoloulos, 2021), (c) chromiteand titanomagnetite-bearing vanadium mineralization and pges, talc deposits (albania; milushi, 2015), and (c) magnesite (albania, bosnia and herzegovina, serbia). (4) late jurassic to cretaceous subduction and obduction of ophiolites with associated banatite magmatism hosting porphyrytype cu-mo-au deposits associated with pt, pa, and se in eastern serbia (vlad and berza, 2003), which have been mined for more than a hundred years in the bor and majdanpek areas. at the same time, most of the external dinaric bauxite deposits formed on the high karst and pre-karst units and are currently in operation in croatia, bosnia and herzegovina, montenegro, and albania, while syngenetic phosphorite-bearing limestones of upper cretaceous age are mined in albania (serjani, 1990; brunett & riggs, 1992). obducted ophiolite crust hosts late cretaceous (fe)ni-co laterites in southern serbia, kosovo, north macedonia, and albania, where several mines with ferronickel production but without cobalt extraction are in operation (horn et al., 2021; economou-eliopoulos et al., 2021). (5) extremely fertile are paleogene collision and (6) neogene post-collision and extension related magmatic and volcanic rocks hosting numerous working pb-zn (ag, au, sb) mining fields and highly successful li-b exploration projects in the sava suture zone in bosnia and herzegovina, serbia, kosovo, and north macedonia. the rich north adriatic late paleogene bauxite deposits (croatia) are contemporaneous (kovačević galović et al., 2012). most of the bentonite and salt deposits are related to the miocene dinaride lake system (gverić et al., 2020). after a century of modern exploitation of traditional metals (fe, al, mn, cr, cu, pb, zn, au, ag, sb…), the adria region also hosts numerous secondary raw materials sites with potential for supplying critical raw materials (crms). šajn et al. (2022) provides insight on the structure and value of such secondary deposits, analysing 1650 mining and metallurgical waste sites, with approximately 2.6 gt of waste. these authors concluded that 42 sites with 270 mt of waste with increased quantities of au, ag, bi, cu, in, mo, rh, sb, w and zn corresponding to a profit of 18,100 mt could be selected for recovery with high economic benefit. within this special issue, several papers deal with critical minerals in adria and secondary raw materials sites (radusinović et al., 2022; steiner et al, 2022; serafimovski et al., 2022). undoubtedly, the raw material potential of the adria region is great, both in metallic and industrial minerals. therefore, the aim of this article is to assess the main strengths and challenges of the mineral sector in the adria region using the following methodology: (1) presentation of the current status of mineral exploration and exploitation; (2) swot (strengths, weaknesses, opportunities, threats) analysis of the adria region, including geological potential, economic environment, legal and regulatory framework, innovation and technological framework, environmental protection, and spatial planning, governmental and social potential, human resources, and educational potential; (3) gap analysis of the adria region; and (4) integration of the obtained results in order to present the roadmap, i.e., a strategic plan that defines a goal or desired outcome and includes the key steps or milestones needed to increase investment in the mineral sector of the adria region. 2. regional geological setting the dinarides are a 650 km long, folded, thrusted, and imbricated belt located between the southern alps to the northwest and the hellenides to the south and southeast, with a northwestsoutheast vergence (pamić et al. 1998). the dinarides consist of several major tectonostratigraphic and lithostratigraphic units of different origin related to the alpine-carpathian orogenic process dating from the palaeozoic to the neogene (pamić et al. 1998; schmid et al. 2020). the predominant structures are large thrusts with sw vergence at a regional scale resulting in knappes and local klippes thrusted onto the adria plate in its present position. the tectonic units include external and internal sectors from the adriatic units toward the northeast to the adjoining tisia mega-tectonic unit (zonation follows the overviews of pamić et al. (1998) and schmid (2020; fig. 1): (1) high karst and pre-karst units, (2) bosnian flysch units, (3) palaeozoic basement units, (4) western vardar ophiolitic unit and (5) the sava suture zone. the high karst and pre-karst units and their correlatives, together with the east bosnian-durmitor zone constitute the external dinarides, while the western vardar ophiolite unit and the sava suture zone represent units of the internal dinarides. the high karst and pre-karst units of the upper palaeozoic basement are overlain by upper permian to norian clastics and platform carbonates with penecontemporaneous rift-related igneous rocks, a norian-lutetian carbonate platform, and eocene overstep flysch sequences. similarly, the internal and external units of the dinarides contain exposed variscan basement units with various degrees of metamorphism (mainly up to greenschist, in some cases up to epidote-amphibolite facies). they are composed of ordovician to carboniferous (permian) metasediments and metavolcanics overlain by a mainly triassic carbonate clastic cover. the bosnian flysch is a 4000-5000 m thick passive continental margin carbonate-clastic tectonostratigraphic unit of jurassic to late cretaceous age. the western vardar ophiolite zone consists of an ophiolite mélange, while mesozoic radiolarite sequences are associated with basalt, greywacke and shale, and large ultramafic thrust sheets. these formations are overlain by late jurassic-early cretaceous and late cretaceous overstep sequences, whereas the sava suture zone contains late cretaceous to palaeogene flysch associated with volcanics, tectonized ophiolite melange, regionally metamorphosed sequences derived from the surrounding late cretaceous-palaeogene rocks and synkinematic granitoids. the geodynamic evolution of the dinarides began with the early permian rifting of the variscan basement (borojević šoštarić et al. 2009; borojević šoštarić et al. 2012), the opening of the tethyan ocean in the late triassic, followed by the late jurassic-early cretaceous subduction and emplacement of the dinaric ophiolites (pamić et al., 1998). parts of the sava suture zone remained open until the early paleogene (schmid et al., 2020). the boundary between the dinarides and the hellenides is considered to be the skutari-peć line, where units continue into albania following the dinaride zonation: (1) the external albanides consisting of a pre-apulian carbonate platform and flysch deposits in early oligocenemiddle miocene foldand thrust knappes of sedimentary rocks derived from the proximal facies of the continental margin of adria (kilias et al., 2001); (2) the pindos zone with jurassic ophiolitic massifs and jurassic-cretaceous ophiolites and sedimentary cover units, underlain with continental and oceanic thrust slices of both (robertson & shallo, 2000); and (3) the korabi-palegonian zone composed of the hercynian basement of ordovician to devonian low-grade metamorphic rocks unconformably overlain by permianlower g eologia c roatica borojević šoštarić et al.: the future of mining in the adria region: current status, swot and gap analysis of the mineral sector 319 triassic rift-related deposits, followed by middle triassic upper jurassic platform carbonates (robertson & shallo, 2000; bortolotti & principi, 2005; muceku et al., 2006). units 2 and 3 correspond to the internal albanides (kilias et al., 2001). the western and eastern vardar ophiolite zones are located west and east of the kopaonik unit, respectively. the western vardar ophiolite belt extends north-west to the sava suture zone, which includes much younger cretaceous ophiolites with a backarc affinity (pamić, 2002; smidt et al., 2008; ustaszewski et al., 2009). the premesozoic and mesozoic lithologies of the western and eastern vardar zone have been intruded and extruded by various types of cenozoic magmatic rocks related to multiphase tectonic episodes; collision, transpression, postcollisional and extension (cvetković et al., 2000; cvetković et al., 2004; koroneos et al., 2011; prelević et al., 2013; schefer et al., 2010). figure 1. a simplified metallogenic map showing the important operating mines of metallic and non-metallic commodities in the adria region). (modified after schmid et al., 2020). g eo lo gi a c ro at ic a geologia croatica 75/special issue 320 3. raw material exploration and exploitation status the exploration and exploitation status is described using the classification of mineral commodities, i.e. materials of economic interest in the earth resource into the following groups, according to the world mining data categories: (i) iron and ferro-alloy metals; (ii) non-ferrous metals; (iii) precious metals; and (iv) industrial minerals. mineral fuels are excluded from consideration. in the western balkan register of the reseerve project, individual deposits are classified according to the inspire directive (inspire directive, 2007/2/ec). based on the d2.8.iii.21 data specification on mineral resources –technical guidelines related to inspire, a statistical comparison with a large number of deposits worldwide allows classification of the deposits as a (very large), b (large), c (medium), or d (small) according to the tonnage of the examined commodity (see annex f of the aforementioned guidelines). commodity rank is based on the endowment, i.e. (cumulated) past production + reserves (not including past production) + resources, or (if the deposit has never been exploited), reserves + resources. as an example, in the case of lead deposits of the a / b / c / d categories, these correspond to 5,000,000 / 500,000 / 50,000 / 5,000 t of lead (metal) content, respectively. alternatively, for industrial minerals such as borates, the a / b / c / d categories correspond to tonnage of commodities of 25,000,000 / 2,000,000 / 500,000 / 100,000 t of borates (b2o3) content, respectively. in the case of a deposit containing several commodities, this classification is expressed for each, and every commodity and the ranking follows the order of importance taking into account the tonnages, scarcity, and price of the commodity. 3.1. exploration status as logged in the west balkan mineral register (2021), and shown in fig. 2 and appendix 1, exploration activities in the adria region, are associated with (i) iron and ferro-alloy metals in albania and north macedonia (iron, manganese, molybdenum, nickel, and titanium). albanian feasibility stage projects are the butmi and sukaxhi titanium magnetite projects (class b) in lezhë municipality and the liqeni i kuq iron-nickel project (class c). the key strength for the country’s development is related to the large ti magnetite deposits, with ti included in the list of critical raw materials for the eu (european commission, 2020). feasibility-stage projects in north macedonia, ranging in size from small to very large (class d to a), include the pehčevo and iberli iron projects, the rakle and studena voda iron-nickel projects, the mitrašinci titanium-iron project, the stogovo manganese project, the strelci molybdenum project, and the petrošnica molybdenum-copper-gold project. the iron ore project at tajmište is under development. (ii) non-ferrous metals in montenegro, bosnia and herzegovina, serbia, north macedonia, and albania (aluminium, copper, lead, lithium, zinc). exploration activities for bauxite in montenegro are focused on eight greenfield sites within the nikšić bauxite field, all of which are at the feasibility study stage. total reserves and probable reserves are 5,466,000 t and 4,318,000 t, respectively. four greenfield bauxite deposits in oštrelj, bosnia and herzegovina, are pending approval. in bosnia and herzegovina, the rupice and veovača lead-zinc deposits (class b and c, respectively) have exploration status, while the vitlovac and kazani lead deposits near the border with serbia (class b) are under construction. in addition, the montenegro lead-zinc deposits (classes c to b) đurđeve vode, paljevine, ribnik, igrišta, brskovo and strmošne bare (sjekrica) and the varine copper project (class b) are at the feasibility stage. the serbian babe lead deposit is currently in the exploration phase. the north macedonian konjsko, borov dol, ilovica, kadiica, kazan dol, plavica and crn vrv copper deposits and the bašibos, jamište and blizanci lead-zinc deposits are at the feasibility study stage. albanian copper deposits in the municipality of fushë arrëz, in the municipality of korce, cifij, and in the municipality of has, nikoliq 2, as well as in the municipality of mirdite, perlati jugor, are also under construction. (iii) precious metals in albania, bosnia and herzegovina, north macedonia and serbia (gold and platinum group metals palladium, platinum, rhodium). the albanian babje gold project (unknown size) and the pge bregu bibes project (class d) are under exploration, as are the bakovići gold project in bosnia and herzegovina and the korkan and bigar hill gold projects in serbia. the north macedonian ilovica, borov dol and plavica pb-zn projects and crn vrv contain significant quantities of gold and/or silver. (iv) industrial minerals in bosnia and herzegovina, serbia and kosovo (boron minerals, kaolinite). li-b mineralization in the adria region is associated with miocene volcanic/pyroclastic activity in the sava suture zone in bosnia and herzegovina, serbia and kosovo. several lithium and borate projects are currently being developed in the region. the jadar project in serbia is at a mature stage and aims to produce battery-grade lithium and borates (feasibility study developed). the project began with the discovery of the unique lithium sodium borosilicate mineral jadarite (linasib3o7(oh)) in 2004. after a decade of exploration, rio tinto (2020) reported measured reserves in 2020 of 16.6 million t at 1.81% li2o and 13.4% b2o3, indicated resources of 55.2 million t at 1.68% li2o and 17.9% b2o3, and inferred resources of 84.1 million t at 1.84% li2o and 12.6% b2o3. the valjevo lithium-borate project, currently in the exploration phase, is located 60-70 km east of jadar in serbia and is a world-class deposit containing at least 10 mt of lithium and 40 mt of boron. in addition, several other lithiumborate exploration projects are located further south (rekovec, piskanja and jarandol projects, central serbia), the viti project in kosovo and the vranje project on the border between serbia and north macedonia. ongoing exploration is reported from the lopare basin in bosnia and herzegovina. 3.2 exploitation status ongoing mining activities in the adria region, shown in fig. 1 and appendix 2, are related to the west balkan mineral register (2021): (i) iron and ferro-alloy metals in albania and bosnia and herzegovina (iron, chromium, nickel, manganese). chromium mining activities in albania are concentrated in several small to medium size deposits (batër (class d), bulqizë (d), vlahën (class d), krastë (class d), thekën (class d), kalimash 2 tr 1 (class c), qafë bulli (class c), kalimash 1 tr 7 (class c), kalimash 3 tr. 6, 6a,a (class d), zogaj 3 (class d), katjel (class d), batër (class d), which contributed to > 40% of the g eologia c roatica borojević šoštarić et al.: the future of mining in the adria region: current status, swot and gap analysis of the mineral sector 321 country’s chromium production in 2019 (reichl & schatz, 2021). albania hosts one nickel and several smallto mediumsized iron-nickel deposits that are currently exploited (bitinckë (class c), skroskë (class c), trull (class d), kodra e trullit (class d), debrovë (class d), kapshticë (class d), and the mamëz nickel ore mine (class c)), resulting in annual nickel production of 2,960 t for 2019 (reichl & schatz, 2021). a small ironnickel ore deposit (groot; class d) is operating in nort macedonia. the ljubija iron ore deposit in bosnia and herzegovina (class b) is mined with a total production of 739,600 t of iron per year (reichl & schatz, 2021; appendix 2). bosnia and herzegovina hosts a single adria manganese mine from a mediumsized popović polje deposit (class c). (ii) non-ferrous metals in the adria region (albania, bosnia and herzegovina, montenegro, north macedonia, serbia) (bauxite (aluminium), copper, lead, selenium, zinc). currently, several albanian underground copper mines are operating in the municipalities of mirditë: munellë (class b); spaç (class b); gurth (plakez) (class c); qafë bari (class c), with an annual production of 5,900 tonnes of copper (reichl & schatz, 2021). a very large copper ore deposit (bučim; class a) is exploited in north macedonia. the annual copper production in serbia is 43,550 t. operating copper mines in the bor district (bor jama, class a; veliki krivelj, class a) and in the municipality of majdanpek (very large deposits of majdanpek north and south revir) are sporadically enriched in selenium. the copper-gold deposit čukaru peki (velojić et al., 2020, 2022; banješević et al, 2019; class a) started initial production in 2021. mining of bauxite is mainly carried out in bosnia and herzegovina, which has a long record in aluminium production. the bauxite mines operating in the federation of bosnia and herzegovina, range in size from small to large (cerovi doci, sobač tribistovo, bojište, jasenjani, vučipolje tribistovo, volujak kadim, bešpelj, crne lokve gnjat, crvene stijene, mratnjača, poljane, studena vrila zagorje and široki brijeg) and large mines in the republic of srpska (such as gradina, braćan, crvene stijene and kosturi) result in a national production of 67.690 t of aluminium extracted from 1,043,343 t of mined bauxite (appendix 2). montenegro is also an aluminium-producing country. in the municipalities of niksic and jablanica, 36,552 t of aluminium are produced from the small mines (class d) of zagrad, durakov do i, biočki stan, and štitovo ii (reichl & schatz, 2021). bosnia and herzegovina exploits large to very large lead deposits at očekalj prgoševo (class a) and srebrenica sase (class b), while montenegro exploits the large šuplja stijena lead-zinc deposit (class a), which produces 3,480 t of lead and 9,520 t of zinc annually (reichl & schatz, 2021). north macedonia hosts very large and large lead-zinc ore deposits (toranica (class a), sasa (class a), zletovo (class b)). the current lead and zinc production of the country is quite significant and amounts to approximately 43,490 t of lead and 31,040 t of zinc, while the total annual production of non-ferrous metals reaches 81,761 t (reichl & schatz, 2021). the annual production of serbian lead-zinc deposits is 13,930 t of lead and 10,560 t of zinc. seven operating copper mines are medium to very large (tenka 1,2 north revir, rudnik, belo brdo, veliki majdan, lece, podvirovi, and grot blagodat). figure 2. simplified metallogenic map showing important mines under development (modified after schmid et al., 2020). g eo lo gi a c ro at ic a geologia croatica 75/special issue 322 (iii) precious metals in north macedonia and serbia (gold, platinum group metals (palladium, platinum), silver). in north macedonia, gold concentrations are mined from the operating bučim porphyry copper mine, contributing to the country’s annual production of 593 kg au (reichl & schatz, 2021). annual production of silver from large to very large lead and zinc deposits (toranica, sasa, zletovo) and copper deposit (bučim) is 17,880 kg. serbian precious metal production in 2019 was equivalent to 1,452 kg of gold, 10 kg of palladium, 10 kg of platinum, and 14,502 kg of silver (reichl & schatz, 2021). some examples of precious metal bearing deposits are the very large copper deposits north and south revir of majdanpek (au, pges), bor-jama of bor (au), medium to large lead-zinc deposits of rudnik (class b), belo brdo (class b), veliki majdan (class c), podvirovi (class c), grot blagodat (class c) containing ag and lece (class b) containing au and ag, whereas copper-gold deposits čukaru peki host significant quantities of gold (velojić et al., 2020, 2022; banješević et al, 2019; class a). (iv) industrial minerals of albania, bosnia and herzegovina, croatia, north macedonia and serbia (bentonite, feldspar, gypsum and anhydrite, kaolin, magnesite, salt, talc, zeolite). a single large bentonite mine is located in bosnia and herzegovina (sokolac, b) and a single feldspar mine in north macedonia (hamzali, class c). evaporite (gypsum and anhydrite) exploitation includes large gypsum mines in albania, bosnia and herzegovina (dočići, b, petkovac, b), croatia with several deposits (the largest is kosovo polje) that contributed to production of 199,255 t in 2019 (reichl & schatz, 2021), and north macedonia (kosovrasti deposit, class c). significant kaolinite deposits exist in bosnia and herzegovina (kobaš, class b), while several serbian deposits are under exploitation. magnesite production in serbia includes several class a magnesite deposits at krive strane i torine, wider locality of čačak, and ribnica, as well as deposits with undetermined reserves, such as brezak. there is significant salt exploitation in croatia (pag, nin, ston) and bosnia and herzegovina (tuzla). talc is mined in bosnia and herzegovina, while zeolites are extracted from several serbian deposits (korminjoš, igroš vidojevići with unknown deposit size). several deposits with ongoing exploitation of industrial minerals with undetermined reserves of kaolinite in serbia are located at kranjani, beli majdan and garas, and borates in the pobrde. mineral production of the 6 adria countries is taken from the world mining data annual report for 2019 (reichl & schatz, 2021). it is given in metric tonnes and in millions of usd (tab. 1). the ranking of exploitation (in tonnes of mined ore) of the 6 adria countries for 2019 is as follows: bih > alb > mkd > mne > hrv. the ranking of revenues from exploitation is as follows: alb > srb > bih > hrv > srb > mne. tab. 1. total mineral production in 2019 by country in metric t and in million usd (reichl & schatz, 2021) 3.3. abandoned mines’ locations based on the west balkan mineral register (2021), cases of abandoned mines of interest for the growth of the mineral sector are associated with (https://reseerve.eu/results): (i) iron and ferro-alloy metals of bosnia and herzegovina and serbia (cobalt, molybdenum). abandoned cobalt mines (lateritic crusts) could be an opportunity for further exploration in albania, as could the abandoned porphyry molybdenum deposits in serbia. (ii) non-ferrous metals in albania, bosnia and herzegovina, croatia and north macedonia, serbia) (antimony, arsenic, bauxite (aluminium), lead, zinc). in albania, there are numerous abandoned hydrothermal antimony mines. in bosnia and herzegovina, antimony is associated with abandoned lead and zinc deposits, whereas within north macedonia it is associated with arsenic ores. in croatia, a number of abandoned bauxite deposits with unidentified reserves containing titanium, vanadium, and gallium are of interest for further exploration. figure 3. a diagram illustrating the preparation process of the mineral sector swot analysis. https://reseerve.eu/results g eologia c roatica borojević šoštarić et al.: the future of mining in the adria region: current status, swot and gap analysis of the mineral sector 323 (iii) industrial minerals of albania (phosphates) the abandoned phosphate deposits of albania are unique commodities in the adria region and are of great interest for further explorationwith the phosphate rocks ranked as cams (european commission, 2020). 4. methodology for the development of road maps 4.1. swot analysis a swot (strengths, weaknesses, opportunities, and threats) analysis is a method used for identifying and analysing internal strengths and weaknesses, as well as external opportunities and threats, that determine current and future operations and help develop strategic objectives (namugenya, 2019). swot is one of the many strategic tools used in the fields of strategic planning and management. it is characterised by its simplicity, and it is widely applied in many sectors (kong, 2008). in order to map and assess the current position of the mineral sector in the adria countries, a swot analysis was conducted within the framework of the present study. the results provided the basis for the development of new strategic plans by combining the key strengths (the advantages over other competitors), weaknesses (the areas that need improvement compared to competitors), opportunities (trends and market gaps to exploit), and threats (external factors that may threaten the businesses) (see fig. 3). initially the 7 key areas for swot analysis were identified followed by the preparation of a swot analysis draft by the representatives of the geological service surveys of each country. these drafts were presented at the national thematic workshops organised in each country, within the framework of the eit raw material project reseerve mineral potential of the esee region. the second step included the involvement of stakeholders from industry, research institutions, academia as well as policy makers from each country, who participated in the national thematic workshops and actively discussed the above prepared swots. these discussions were organised in the form of teamwork where the teams consisted of members representing different types of stakeholders. such discussions were organised in person at the national thematic workshops in bosnia and herzegovina, croatia and montenegro. due to the covid 19 pandemic, in the remaining countries (albania, north macedonia and serbia), the national thematic workshops were organised online, and the opinions of different stakeholders were collected in advance in the form of questionnaires and discussed at the national thematic workshops. for the finalisation of the swot analysis for each country and for the consistent assessment of the available data from the national thematic workshops, the reseerve project deliverables, the reports of the international financial institutions and other published data were reviewed (step 3). within this framework the following seven key areas that have a positive or adverse impact on the development of the mineral sector were examined with a set of parameters and key performance indicators: 1. geological potential: ores, industrial minerals, crms (european commission, 2020), secondary raw materials (srms), size of reserves, type of reserves (probable, proven), unknown reserves, exploration activities, greenfield areas and mines in feasibility stage, mines under development, research to produce added value materials, mainly from industrial minerals and rocks. 2. economic environment: current and projected mineral production of the country, global demand for raw materials, economic stability of the country, gdp, gdp per capita, tax system, ease of doing business, infrastructure, financial product of mining, investment in the mining sector, state aid to the mining sector. 3. legal and regulatory framework: state mineral policy and mining regulations; licencing procedures; exploration, mining, environmental and ownership regulations; control mechanisms; adoption of eu environmental legislation. 4. innovation and technological framework: mining development status, innovation funding opportunities, technological status of processing plants, research and development (r&d) status. 5. environmental protection and land use planning: protected areas, waste management, contaminated brownfield sites, reclamation of old sites, land use planning, alternative use of previously mined areas. 6. government and societal potential: resource planning / sustainable management of resources, accessibility to resources, administrative drawback permitting/concessions, spatial planning, state r&d strategy. 7. human resources and educational potential: stakeholder involvement, education level and status of research and development, personnel qualified for mining activities, capacity building, and demographics. as a final step (step 4), the national swot analyses was unified into an integrated analysis for the adria region. the geological potential is unique for each country, however, the legal, regulatory, land use planning and educational potential for the former yugoslavian counties stems from the same legisfigure 4. a schematic diagram illustrating the generic methodology of the gap analysis to determine the key steps for sustainable development of the extractive sector. g eo lo gi a c ro at ic a geologia croatica 75/special issue 324 lative processes, so they are comparable. croatia, as a member of the european union (eu), has already implemented the eu legal framework. 4.2. gap analysis gap analysis was used to identify the main gaps/barriers/obstacles in performing businesses requirements. to determine those gaps, it is essential to refer to where the entity/sector is today, and where it may go in the near future, setting the initial situation, the target situation, and the measures to be taken towards this direction (fig. 4). to assess the existing status of the sector, the available information, as derived from the components of swot analysis were used. the evaluation included the identification of factors significantly affecting mineral sector growth, considering the specific characteristics of each adria country. following that, the major limitations preventing the adria region’s mineral sector boost were recorded and ranked, demonstrating the priority areas where countries present the same needs/gaps or contrasting ones. limitations were recorded taking into consideration the seven, key-areas of swot analysis. swot and gap analyses were used in the present study as the basis for the strategic plans to guide development in the raw materials business and strategic initiatives. the final step was the selection of the actions to be taken for the sustainable development of raw materials in the adria region via roadmaps for the implementation in practise. those actions are incorporated into the adria region’s roadmap, focusing on the areas of geological, economic and business framework where the main constraints were recorded (fig. 5). 5. results and discussion 5.1. swot analysis of the adria region 5.1.1. geological potential the strength of the adria countries regarding geological potential relates to their significant reserves of primary metallic (cr, sb, pb, zn, mo, au, li) and industrial minerals (bauxites, borates). these deposits are included in the west balkan mineral register (2021) following the t d2.8.iii.21 data specification on mineral resources –technical guidelines related to inspire directive (inspire directive, 2007/2/ec). moreover, these countries have active exploration areas, as well as a large number of developed mines (see fig. 1). however, there is a lack of recent systematic exploration and corresponding databases for new crms for emerging technologies (li, b, ree) which is reported as a main weakness. another weakness regarding further exploration of the geological potential of these countries focuses on the peculiarities of karst bauxites, which are found in numerous small deposits (class d). opportunities lie in the potential and current greenfield exploration and brownfield operations (schodde, 2021). significant greenfield exploration in crms such as li, b, sb, and rees in bauxites are recorded (giannakopoulou et al., 2021). brownfield operations facilitate geological research and increase the existing reserves of primary and secondary (mining waste, tailings and metallurgical waste) metallic and industrial minerals. 5.1.2. economic environment the total mineral production (excluding fossil fuels) of the adria region in 2020 was 2,644 million usd (reichl & schatz, 2022). hence, it contributed 1.65% of the sum of their nominal gdps (based on reichl and schatz, (2022)), with albanian mineral production being the highest contributor (1550 million usd, contributing more than 10% of the albanian nominal gdp) and croatia the lowest (15 million usd). the ease of doing businesses in the adria countries ranged approximately from 65% to 80%, with bosnia and herzegovina ranked in the lowest position among the 6 adria countries examined (giannakopoulou et al., (2021)). in calculating the overall ease of doing business, indicators such as starting a business, obtaining construction permits, electricity supply, registering property, obtaining credit, protecting minority investors, paying taxes, trading across borders, enforcing contracts, and resolving insolvency were considered. four of the six economies under study were ranked as high as 51st figure 5. diagram illustrating the overall methodology. g eologia c roatica borojević šoštarić et al.: the future of mining in the adria region: current status, swot and gap analysis of the mineral sector 325 out of 190 economies, indicating that there is a framework in place to support future investment in the mineral sector (doing business, 2021). however, economic instabilities in non-eu countries and underdeveloped local infrastructure (e.g., transportation infrastructure, energy infrastructure) are seen as weaknesses for the sector’s growth (world bank 2021). the general increase in demand for raw material (reichl & schatz, 2021) and the interest of international mining companies in exploration and exploitation represents an opportunity for the mineral sector in adria countries (ebrd, 2017; schodde, 2021). however, the volatility of commodity prices on the world market and the underdeveloped downstream industry for certain raw materials are seen as a threat 5.1.3. legal and regulatory framework in all the adria countries, mineral resources are protected by the constitution and the existing legal framework includes regulations for exploration, mining and mine waste treatment. however, methods for estimating reserves are not aligned with international standards, such as perc/jorc/unfc (giannakopoulou et al., 2021). moreover, concession/exploration licencing procedures are reported as lengthy and in need of significant simplification, with institutional quality affecting investment activities (estrin & uvalic, 2014). in bosnia and herzegovina, further difficulties are faced due to the fact that the country consists of two entities, the republic of srpska and the federation of bosnia and herzegovina, with each entity having its own legislative, executive, and judicial procedures. in the federation of bosnia and herzegovina, a large part of the entity’s authorities has been transferred to the regional governments. a great opportunity for the adria countries is that a large number of concessions for exploration and mining were issued by the local governments in the last 20 years. however, there is a threat of the application of more stringent environmental laws that could lead to additional restrictions on the permitting and implementation of mining operations. 5.1.4. innovation and technological framework among the adria candidate and potential eu candidate countries for which data are available, gross domestic expenditure on r&d as a percentage of gdp in 2018 and 2019 ranged approximately from 0.2% in bosnia and herzegovina to 1% in serbia, compared with an average of 2.2% in the eu (european commision, 2022). industry stakeholders report a lack of investment in green technology and research infrastructure for mining and processing. external funding for innovation and technological development are expected from regional, national and eu sources. 5.1.5. environmental protection and land use planning there are positive examples the rehabilitation of old mining sites (williams & maslać, 2010) however, the lack of harmonisation of spatial planning documents in regions with potential for mining activities is considered as a weakness. consideration of protected areas in spatial planning documents is an opportunity, however, enforcement of environmental legislation will impose additional restrictions on mining in noneu countries that are in the process of implementing natura 2000. 5.1.6. government and social potential all adria countries have national strategies to promote the sustainable development of mineral resources. however, the wider society is not sufficiently informed about the importance of raw materials in every-day life. low social acceptance of mining and processing by local communities and non-governmental organizations poses a serious threat to the further development of the mineral sector. 5.1.7. human resources and educational potential the strength of the adria region in terms of human resources and educational potential lies in the existing higher education institutions that cover the entire commodity value chain. moreover, the active presence of the national organizations that promote the r&d of science and technology, as well as technological innovation activities considers another strength, towards this aim combined with various research & innovation programs for scientists and professionals that are currently underway. however, higher education raw materials related programs often need to be updated, and students’ interest in enrolling in these programs is low. in addition, there is an inadequate supply of lifelong learning courses for existing raw material professionals. current activities in the adria region to develop new higher education programs that produce t-shaped professionals (collaborative, empathetic, enthusiastic, open-minded, and visionary) and lifelong learning courses are seen as a great opportunity for the mineral sector in the future. however, declining demographics and a brain drain pose a serious threat (murphya and pacherb, 2021); 5.2. gap analysis of the adria region following the swot analysis, a gap analysis was performed to determine barriers and obstacles for the further exploitation of the mineral sector in the adria region. the barriers and obstacles were identified, emphasizing a countries’ current economic and business environment, mineral production, as well as geological potential, infrastructure, mining legal framework, support of the local communities and mineral state policies. regarding policies adversely impacting the raw materials sector, the emphasis is placed on permit issues and the cooperation of competent authorities. gaps regarding mining in protected areas, spatial planning and its harmonization with mining legislation are also highlighted. regarding social aspects, a region’s needs for skilled human resources and capacity building, are also recorded in the adria region. a challenging obstacle is the acceptance of mining activities by local communities. general problems are: (1) the low level of confidence in the government and public administrations of adria countries (often perceived by impacted local community to be driven by particular interest groups or as corrupt) to properly regulate the mining industry; (2) misinterpretation of the environmental risks of the project, usually by publicly exposed non experts, leading the local community to believe that economic benefits of the project are negligible compared to the overall risks for water, soil and air, and (3) infrequent, inadequate or delayed communication of the mining companies toward the local community leaving the impression of non-transparencies. very often, the initial conflict between local communities and the mining companies are recognised by various political parties, activists, or ngo as an ideal setting for popularity-raising, free media space or self-promotion, usually prior to approaching local or national elections. even though in the reseerve project, the construction of the west balkan mineral register (2021) database as per the inspire guidelines (inspire directive, 2007/2/ec) covered areas where improvements are needed, gaps such as the lack of harmonisation of reserves estimation with international standards (giannakopoulou et al., 2021), and the absence g eo lo gi a c ro at ic a geologia croatica 75/special issue 326 of systematic exploration in some of the new areas presenting geological potential, are considered as constraints for the sector’s development. the economic environment for investments in the adria countries is characterized by a rather low cooperation among the public and private sectors, with the need for more advanced techniques/tools being considered as “a must” for investment enhancement, as reported by the relevant stakeholders. the need to strengthen/reform/update the current legal and regulatory framework is a common conclusion among the 6 adrian countries examined in this study. areas to be improved are summarized below and include; the importance of simplification of the current raw materials legislation, given that the procedures for obtaining concessions and exploration licenses was consistently considered as relatively time-consuming and complicated, there is an urgent need to implement reforms in line with the eu legislation, and raw materials strategies, as well as the implementation of activities for the long-term mineral resources’ policies (giannakopoulou et al., 2021). despite the fact that the 6 examined countries have recently upgraded their national legal framework in relation to the mineral sector and to business environment regulatory areas, it is also recognized that mineral policy, land planning, mineral laws and regulations for exploration and mining, need further reforms to integrate spatial planning legislation and provide a clear mineral policy and strategy regarding access to resources and safeguarding of reserves (e.g., mati, 2017). concerning spatial planning, one of the gaps recorded is the absence of its harmonization with mineral plans. moreover, alignment of spatial planning with other land-uses, e.g., spatial mineral plans, at different levels of state, county, municipality, are required for enhancing the internal investments (giannakopoulou et al., 2021). furthermore, as reported by the stakeholders, active in the adria region, human resources, and capacity building are areas for improvements needed to support the sector’s potential growth. a low level or absence of cooperation between universities, industry, research institutions, and the state authorities represent a major gap to be covered in future steps. at the same time, the reduced number of skilled professionals and technical staff due to the “brain drain” (murphya and pacherb, 2021) and the low interest for studies in the raw materials fields such as geology, results in the generation of a rather low number of professionals to cover the sector’s needs. the reducing number of skilled raw materials professionals combined with the lack of knowledge of new technologies, mainly for the exploitation of crm deposits are constraints to be mitigated (giannakopoulou et al., 2021; melcher & reichl, 2017). 5.3. roadmap for the raw materials investment in the adria countries as already described, swot/gap analysis for the development of the raw materials sector in the adrian countries examined was performed in the present study. this followed a comprehensive literature review, and active consultation with the stakeholders, with the emphasis placed in the 7 national thematic workshops conducted in the countries under study. subsequently, assessment and evaluation of the above swot/gap analysis results, provided the basis for the development of a general strategy roadmap presenting the relevant actions required for the sustainable development of the mineral sector of the adria region. with this aim, the general strategy roadmap included the following actions, related to 5 key areas linked with the swot/gap analysis components: stakeholders’ consent and awareness. local communities/ public authorities/ professional associations are key stakeholders for the implementation of the different stages of a mining project, however public consultation and permit issue is a process often delayed in adria countries. given that social acceptance and stakeholders’ consent is required during the whole life cycle of a mining project, starting from permits, to operation, closure and post-closure stages, agreement and active cooperation among authorities and stakeholders is considered a necessity. constitutional acts of the adria countries are defining mineral resources to be of primary national interest, however proper education on the importance of the raw materials sector in everyday life (“we grow it, or we mine it = agriculture and raw materials”) is left to be promoted by professional organisations with limited capacities and knowledge. geology is the only natural science outside secondary school curricula, and often erroneous/ unreviewed information on mineral resources appears in textbooks, influencing an early negative perception of the mining and metallurgical community by the wider society. the authors suggest including important elements on raw materials exploration, mining, processing and recycling in the primary and secondary schools’ curricula as well as creating relevant life-long learning courses for high-school teachers. wider society learning courses should bring basic understanding to the broader public. timely awareness-raising campaigns starting prior to the first geological prospection is proposed as one of the tools, aiming to inform different types of stakeholders on employment opportunities in the raw materials sector, its contribution to local infrastructure development, the regional and national economies, and the need to jointly mitigate the obstacles that adversely impact the development of the region, and the steps required to achieve the social license to operate. thus, wider society learning and awareness raising will contribute to avoid misconceptions and build a trustworthy relationship between the mining industry –and local stakeholders setting the basis for the required social acceptance. quality of geological potential data. in the adria region, geological potential data are available in the countries’ digital databases. however, in order to attract investors’ interest and financing, in addition to the identification of the type of resources, i.e., inferred, indicated, measured, or the classification of the reserves of a deposit for the commodities of interest into probable and proved, it is also essential that domestic or foreign companies report the results of their exploration activities and classify mineral resources, and ore reserves according to internationally accepted standards. as noted in the gap analysis, the above classification is proposed to be conducted in line with the international codes for public reporting of exploration results, mineral resources and ore reserves, including jorc (australian joint ore reserves committee code), perc (pan european reserves and resources reporting committee code), cim (canadian institute of mining, metallurgy and petroleum), unfc (united nation framework classification for resources) etc. (giannakopoulou et al., 2021). moreover, and in order to improve the level of confidence of the available geological data and reserves estimation per commodity, further exploration work for certain primary raw materials is proposed as an action to support the development of the rms sector. in summary, further exploration to enhance the qualg eologia c roatica borojević šoštarić et al.: the future of mining in the adria region: current status, swot and gap analysis of the mineral sector 327 ity control of available minerals register’s data, and alignment with internationally acceptable codes, are considered as actions leading to the sector’s development. reforms/updates of legislation and codification of regulations: based on the swot and gap analysis results, interventions in the following five areas were identified as a priority in order to circumvent legal constraints: (1) mineral policy and strategy of the state; (2) licensing and permit procedures for exploration and exploitation activities; (3) royalties / fees and compensatory benefits; (4) harmonization of spatial plans, and alignment with the eu environmental legislation to delineate and manage nature protected areas and restore historic and/or abandoned sites, (5) codification and simplification of the mining regulations and legislation, is also necessary, while the mapping of additional areas of legal constraints is recommended (giannakopoulou et al., 2021). the adria countries examined, take steps for upgrading mining legislation, focusing on the direction of mining activities to become an essential pillar for the economy (sohol, 2017). even though the national legal framework related to the minerals sector and the business environment regulatory areas has been recently upgraded, issues such as protection of the sustainable development of mineral resources of public importance, in line with the eu legislation are not considered in the currently prevailing legislation. moreover, simplification of the permit procedures is essential, regulating the competencies and the responsibilities of the related authorities, and enhancing the cooperation among different levels of state government. the lack of harmonisation among the different levels of spatial planning, and the nonalignment with eu directives needs to be mitigated with a special spatial mineral plan per country. royalties / fees need to be re-assessed taking into consideration the value of the commodity mined, while the need for benefits for local communities was also noted. competitiveness and financing dimension: stakeholders consider that the competitiveness of the sector is a multi faceted task covering areas such as enhancing research and development activities, technology transfer for upgrading and increasing the capacity of existing mines and plants, and vertical integration of the mineral sector. funded research programs, funding development and reconstruction are common practices to attract eu and international financial resources for enhancing exploration and other research activities of the sector and supporting growth in investments. it is thus concluded that reforms are needed for attracting investors and creating a favourable business environment. indicators such as starting a business, dealing with construction permits and enforcing contracts were determined as significant aspects that need improvement in order to further enhance adria region’s business environment (giannakopoulou et al., 2021; https://www.doingbusiness.org). with this aim, scoping technical studies per country are proposed for identifying the special needs to promote countries’ potential in raw materials. technology transfer, application of innovative methods for exploration, exploitation, or processing, increase of the processing plants’ capacity, modernizing facilities, reprocessing srms, etc., will result in the reduction of operating costs, and overall improvement of economic performance, the vertical integration of the raw materials sector, the production of new added value products and the opening of new markets. actions for the reduction of the environmental footprint of the sector including extraction waste management and reclamation of mined out areas should also be included. moreover, focused funded research projects in cooperation with the industry are proposed, in order to solve specific technical problems. with this aim, comprehensive review studies may be needed on the state-of-the art techniques for the overall treatment of selected mineral raw materials including crms. market research and feasibility studies covering the overall spectrum of the products of interest are required in order to document the sustainability of the proposed changes and/or upgrades in mines and plants. human resources and capacity building. the need to enhance the skills of the technical, scientific and managerial personnel involved in the whole cycle of raw materials activities is a common conclusion. reduction of skilled professionals and technical staff linked to a “brain drain“ (murphya & pacherb, 2021) or for other reasons (e.g. limited interest in the raw materials sector in general) and limited expertise in new technologies for exploration, mining and processing of ores and wastes, are some of the issues reported by the stakeholders in the countries examined. gaps have been also noticed between the existing educational programs and the present and future needs of the raw materials sector. a need to enhance the cooperation in the knowledge – triangle of universities, research and technology organizations, and industry in different areas was also noted (giannakopoulou et al., 2021). capacity building programs for training of scientists and technical staff, given the increased emerging needs in the mineral sector of the region (schodde, 2021), are considered as necessary, with croatia having already made steps as an active partner in the regional inovation scheeme (ris) projects founded by the european institute for inovation and technology (eit) projects. strengthening innovation, entrepreneurship, and cooperation with the participation in eit raw materials ris or other types of eu funded projects, as well involvement of the specific target groups in thematic training, and lifelong learning programs are proposed as key measures for technology transfer and capacity building. 6. conclusions the adria region has a long history of mining, however the mineral sector currently faces a variety of challenges that prevent its sustainable development. the swot analyses performed for the esee countries examined, albania, bosnia and herzegovina, croatia, montenegro, north macedonia and serbia covered parameters such as geological potential, economic environment, legal and regulatory framework, innovation and technological framework, environmental protection and land use planning, governmental and societal potential, human resources, and education potential. swot analyses results served as the basis for the gap analysis, and the integration of the results obtained into regional strengths and challenges in order to create a roadmap for investment in the mining sector. adria countries have significant reserves of primary metallic and industrial minerals and active exploration areas, as well as a large number of operating mines. the total mineral production versus the current gdp for the adria countries was calculated as close to 4%, whereas in all countries examined, mineral resources are protected by the constitution and there is a legal framework regulating exploration, mining and treatment of mine waste. moreover, the presence of national higher education institutions that cover the entire raw materials value chain, as well as g eo lo gi a c ro at ic a geologia croatica 75/special issue 328 national organizations that facilitate r&d activities are considered as factors supporting the development of the mineral sector. despite these strengths, the mineral sector in the adria region faces a number of challenges related to reduced social acceptance, the lack of new exploration campaigns in many areas, estimation of resources or reserves not aligned with international codes and standards, and lack of skilled technical, scientific and managerial personnel involved in the whole cycle of mineral activities. the adria countries have uneven potential in terms of mineral resources. however, apart from albania, they all emerged from the disintegration of the same state (yugoslavia) and present many similar weaknesses regarding the prevailing business environment and business opportunities. croatia stands out from the other adria countries in terms of opportunities, as it is the only eu member state. actions proposed for the sustainable development of the mineral sector in the adria region include: awareness raising campaigns to obtain the required social license to operate and gain stakeholders’ knowledge of the sector and consent; further exploration activities to increase the level of confidence and reserves, quality control of the west balkan mineral register’s data (west balkan mineral register, 2021) and alignment with internationally recognized codes, such as jorc, perc, cim, unfc; harmonization with spatial planning and alignment with relevant eu environmental eu legislation; reforms to attract investors and create a favourable business environment focusing on areas such as opening business/ dealing with construction permits/enforcing contracts; capacity building programs. acknowledgement this contribution is supported by the project “reseerve mineral potential of the esee region” funded by the european institute of innovation and technology (eit), a body of european union, under the horizon 2020, the eu framework programme for research and innovation. the authors would like to thank for the help following reseerve project partners: geological surveys of slovenia, albania, croatia, the federation of bosnia and herzegovina and the republic of srpska and montenegro as well as faculty of mining and geology of university of belgrade and macedonian ecological society. data presented in this paper are related to deliverables reseerve d6.1; d6.2; d6.3, and the west balkan mineral register (2021). references banješević, m., cvetković, v., von quadt, a., ljubović obradović, d., vasić, n., pačevski, a. & peytcheva, i. (2019): new constraints on the main mineralization event inferred from the latest discoveries in the bor metallogenetic zone (bmz, east serbia).– minerals 9/11, 672. doi: 10.3390/ min9110672 borojević šoštarić, s., palinkaš, a.l., strmić palinkaš, s., bermanec, v., neubauer, f., spangenberg, j.e. & prochaska, w. (2009): origin of siderite–barite-polysulfide mineralisation in petrova and trgovska gora mts., nw dinarides.– miner petrol, 97, 111–128. doi: 10.1007/s00710009-0065-2 borojević šoštarić, s., neubauer, f., handler, r & palinkaš, l.a. (2012): tectonothermal history of the basement rocks within the nw dinarides: new 40ar/39ar ages and synthesis.– geol carpath, 63/6, 441–452. doi: 10.2478/ v10096-012-0034-2 bortolotti, v. & principi, g. (2005): tethyan ophiolites and pangea break-up.– the island arc, 14, 442–470. doi: 10.1111/j.1440-1738.2005.00478.x coface (https://www.cofacecentraleurope.com/economic-analysis/metals (accessed on 1st of june, 2022). cvetković, v., knežević, v. & pecskay, z. (2000): tertiary igneous formations of the dinarides, vardar zone and adjacent regions: from recognition to petrogenetic implications.– in: karamata, s. & janković, s. (eds.): geology and metallogeny of the dinarides and the vardar zone. the academy of sciences and arts of the republic of srpska, collections and monographs 1, dpt. of natur., math. and techn. sci., 1, 245–253. cvetković, v. prelević, d., downes, h., jovanivić, m., vaselli, o. & pécskay, z. (2004): origin and geodynamic significance of tertiary postcollisional basaltic magmatism in serbia (central balkan peninsula).lithos, 73, 3–4, 161–186. doi: 10.1016/j.lithos.2003.12.004 dimitrijević, m.d. (1982): dinarides: an outline of the tectonics.– earth evol. sci. berlin, 2/1, 4–23. dimitrijević m.d. (1997): geology of yugoslavia.– geol. survey gemini, belgrade, 1–187. doing business (2021) https://www.doingbusiness.org (accessed on 3rd of may, 2021). ebrd (2017): european bank for reconstruction and development. extractive mining industries strategy 2018–2022. 2017. available online: https://www.ebrd.com/ mining%20operations%20policy.pdf (accessed on 3rd of march, 2021) economou-eliopoulos, m, laskou, m., eliopoulos, d.g., megremi, i., kalatha, s. & eliopoulos, g.d. (2021): origin of critical metals in fe– ni laterites from the balkan peninsula: opportunities and environmental risk.– minerals, 11/9, 1009. doi: 10.3390/min11091009 european commission (2020): critical raw materials resilience: charting a path towards greater security and sustainability.– com 474 final, brussels. estrin s. & uvalić, m. (2014): fdi into transition economies: are the balkans different?.– economics of transition, 22/2, 281–312. doi: 10.1111/ecot.12040 giannakopoulou, s., chalkiopoulou, f. & adam, k. (2021). mineral raw materials’ resource efficiency in selected esee countries: strengths and challenges.– materials proceedings, 5/1, 83. doi: 10.3390/materproc2021005083 gverić, z., hanžel, d., kampić, š., pleša, a. & tibljaš, d. (2020): comprehensive characterisation of bentonites from croatia and neighbouring countries.– geologia croatica, 73/1, 29–48. doi:10.4154/gc.2020.02 inspire directive, 2007/2/ec: infrastructure for spatial information in europe, d2.8.iii.21 data specification on mineral resources –technical guidelines. https://inspire.ec.europa.eu/documents/data_specifications/inspire_dataspecification_mr_v3.0_rc2.pdf horn, s., gunn, a.g., petavratzi, e., shaw, r.a., eilu, p., törmänen, t., bjerkgård, t., sandstad, j.s., jonsson, e., kountourelis, s. & wall, f (2021): cobalt resources in europe and the potential for new discoveries– ore geology reviews, 130, 103915. doi: 10.1016/j.oregeorev.2020.103915 kilias, s.p., naden, j., cheliotis, i., shepherd, t.j., constandinidou, h., crossing, j., & simos, i. (2001): epithermal gold mineralization in the active aegean volcanic arc: the profitis ilias deposit, milos island, greece.– mineralium deposita, 36, 32–44. doi: 10.1007/s001260050284 kong, e. (2008): the development of strategic management in the non‐profit context: intellectual capital in social service non‐profit organizations.– international journal of management reviews, 10/3, 281–299. doi: 10.1111/j.1468-2370.2007.00224.x koroneos, a., poli, g., cvetković, v., christofides, g., krstić, d. & pécskay, z. (2011): petrogenetic and tectonic inferences from the study of the mt cer pluton (west serbia).– geol. mag., 148/1, 89–111. doi: 10.1017/ s0016756810000476 kovačević galović, e., ilijanić, n., peh, z., miko, s. & hasan, o. (2012): geochemical discrimination of early palaeogene bauxites in croatia.– geologia croatica, 65/1, 53–65. doi: 10.4154/gc.2012.04 mati, s. (2017): facing the global challenges in mining activities: adoption of legislation and mining policies in albania. 3/4, https://cqegheiulaval.com/facing-theglobal-challenges-in-mining-activities-adoption-of-legislation-and-mining-policies-in-albania/ melcher, f. & reichl, c. (2017): economic geology of the eastern and southeastern european (esee) region.– bhm bergund hüttenmännische monatshefte, 162, 238–244. doi: 10.1007/s00501-017-0625-4 milushi, i. (2015): an overview of the albanian ophiolite and related ore minerals.– acta geologica sinica (english edition), 89, 2, 61–64. doi: 10.1111/17556724.12308_39 muceku b., mascle, g. & tashko, a. (2006): first results of fission-track thermochronology in the albanides.– in: robertson, a.h.f. & mountrakis, d. (eds.): tectonic development of the eastern mediterranean region. geological society special publication, 260, 539–556. doi: 10.1144/gsl.sp.2006.260.01.23 https://www.cofacecentraleurope.com/economic-analysis/metals https://inspire.ec.europa.eu/documents/data_specifications/inspire_dataspecification_mr_v3.0_rc2.pdf https://inspire.ec.europa.eu/documents/data_specifications/inspire_dataspecification_mr_v3.0_rc2.pdf https://inspire.ec.europa.eu/documents/data_specifications/inspire_dataspecification_mr_v3.0_rc2.pdf https://cqegheiulaval.com/facing-the-global-challenges-in-mining-activities-adoption-of-legislation-and-mining-policies-in-albania/ https://cqegheiulaval.com/facing-the-global-challenges-in-mining-activities-adoption-of-legislation-and-mining-policies-in-albania/ https://cqegheiulaval.com/facing-the-global-challenges-in-mining-activities-adoption-of-legislation-and-mining-policies-in-albania/ g eologia c roatica borojević šoštarić et al.: the future of mining in the adria region: current status, swot and gap analysis of the mineral sector 329 murphy, m. & pacher, c. (2021): bridging the gap: brain drain to brain circulation.– procedia computer science, 200, 556–565. doi: 10.1016/j.procs.2022.01.253 namugenyia, c., nimmagaddab, s. l., & reinersc, t. (2019). design of a swot analysis model and its evaluation in diverse digital business ecosystem contexts – procedia computer science, 159, 1145-1154. doi:10.1016/j. procs.2019.09.283. palinkaš, l.a., borojević šoštarić, s. & strmić palinkaš, s. (2008): metallogeny of the northwestern and central dinarides and southern tisia.– ore geology reviews, 34/3, 501–520. doi: 10.1016/j.oregeorev.2008.05.006 pamić, j. amić, j., gušić, i. & jelaska, v. (1998): geodynamic evolution of the central dinarides.– tectonophysics, 297/1–4, 251–268. doi: 10.1016/s0040 1951(98)00171-1 pamić j. (2002): the sava suture zone of the dinarides and hellenides versus the vardar ocean.– eclogae geol. helv. 95, 99–113. doi: 10.5169/seals-168948 prelević, d., jacob, d.e. & foley, s.f. (2013): recycling plus: a new recipe for the formation of alpine-himalayan orogenic mantle lithosphere.– earth and planetary sciences letters, 362,187–197. doi: 10.1016/j.epsl.2012.11.035 radivojević, m., rehren, t.h., pernicka, e., šljivar, d., brauns, m., borić, d. (2010): on the origins of extractive metallurgy: new evidence from europe.– journal of archaeological science, 37, 2775–2787. doi: 10.1016/j. jas.2010.06.012 radusinović, s. & papadopoloulos, a. (2021): the potential for ree and associated critical metals in kartic bauxites and bauxite reisude of montenegro.– minerals, 11, 975–1018. doi: 10.3390/min11090975 radusinović, s., šajn, r., jovanović, b., rokavec, d., hribernik, k., abramović, v., draksler, m., danilović, i. & jovanović, m. (2022): the primary and secondary mineral resources of montenegro and their mapping into european data model.– geologia croatica, this issue. reichl, c. & schatz, m. (2021): world mining data 2021, vol. 36.– federal ministry of agriculture, regions and tourism of republic of austria, internetional organizing committee for the world mining congresses, 266 p. reichl, c. & schatz, m. (2022): world mining data 2022, vol. 37.– federal ministry of agriculture, regions and tourism of republic of austria, internetional organizing committee for the world mining congresses, 266 p. rio tinto (2020) https://www.riotinto.com/news/releases/2020/rio-tinto-declaresmaiden-ore-reserve-at-jadar (accessed on 5th of december, 2021). robertson, a.h.f. & shallo, m. (2000): mesozoic–tertiary tectonic evolution of albania in its regional eastern mediterranean context.– tectonophysics, 316, 197–254. doi:10.1016/s0040-1951(99)00262-0 schefer, s., cvetković, v., fügnschuh, b., kounov, a., ovtcharova, m., schaltegger, u. & schmid, s.m. (2010): triassic metasediments in the internal dinarides (kopaonik area, southern serbia): stratigraphy, paleogeographic and tectonic significance.– geologica carpathica, 61/2, 89–109. doi: 10.2478/v10096-010-0003-6 schmid, s.m., fügenschuh, b., kounov, a. & van hinsbergen, d. (2020): tectonic units of the alpine collision zone between eastern alps and western turkey.– gondwana research, 78, 308–374. doi: 10.1016/j.gr.2019.07.005. schodde, r. (9 march, 2021). industry spotlight on the western tethyan. 5th annual tethyan belt session, pdac [powerpoint slides]. toronto, canada. available at: https://minexconsulting.com/industry-spotlight-on-the-western-tethyan/ serafimovski, s., tasev, g., stafilov, t. (2022) general features of some pollymetallic ore deposits in the republic north macedonia.– geol. croat., 75/special issue, ... doi: 10.4154/gc.2022.27 serjani, a. (1990): chemical and mineralogical composition of phosphorites of the kurveleshi anticline belt (albania).– mineral. wealth, 67, 43–50. sohol, m. (2017): facing the global challenges in mining activities: adoption of legislation and mining policies in albania (vol 3, n4).– quebec council for geopolitical studies, cqeg. https://cqegheiulaval.com/facing-the-global-challenges-inmining-activities-adoption-of-legislation-and-mining-policies-in-albania/ steiner, t.m.c., bertrandsson erlandsson, v., šajn, r. & melcher, f. (2022): preliminary chemical and mineralogical characterization of tailings from base metal sulfide deposits in serbia and north macedonia.– geologia croatica, this issue. šajn, r., ristović, i. & čeplak, b. (2022): mining and metallurgical waste as potential secondary sources of metals – a case study for the west balkan region.– minerals, 12, 547. doi: 10.3390/min12050547 tomašić, n., čobić, a., bedeković, m., miko, s., ilijanić, n., gizdavec, n. & matošević, m. (2021): rare earth elements enrichment in the upper eocene tošići-dujići bauxite deposit, croatia, and relation to ree mineralogy, parent material and weathering.– minerals, 11/11, 1260. doi: 10.3390/ min11111260 united nations (2020): united nations framework classification for resources.– ece energy series, 26. doi: 10.18356/44105e2b-en ustaszewski, k., schmid, s.m., lugović, b., schuster, r., schaltegger. u., bernoulli, d., hottinger, l., kounov, a., fügenschuh, b. & schefer, s. (2009): late cretaceous intra-oceanic magmatism in the internal dinarides (northern bosnia and herzegovina): implications for the collision of the adriatic and european plates.– lithos, 108, 1–4, 106–125. doi: 10.1016/j. lithos.2008.09.010 velojić, m., bertrandsson erlandsson, v., melcher, f., onuk, p., jelenković, r. & cvetković, v. (2022): trace elements in pyrite from the čukaru peki porphyry cu–high-sulfidation deposit, serbia: implications for ore evolution in a polyphase hydrothermal system.– geologia croatica, this issue. velojić, m., jelenković, r. & cvetković, v. (2020): fluid evolution of the čukaru peki cu-au porphyry system (east serbia) inferred from a fluid inclusion study.– geologia croatica 73/3, 197–209. doi: 10.4154/gc.2020.14 vlad, s. & berza, t. (2003): banatitic magmatic and metallogenetic belt: metallogeny of the romanian carpathians segment.– studia universitatis babeş-bolyai, geologia, xlviii/1, 113–122. doi: 10.5038/1937-8602.48.1.10 west balkan mineral register (2021) https://reseerve.eu/results (accessed on 31st of december, 2021). williams, s. & maslać, s. (2010): strengthening capacities in western balkan countries to address environmental problems through remediation of high priority hot spots.– in: global environmental change: challenges to science and society in southeastern europe, springer, dordrecht, 259–266. (world bank (2022) https://www.worldbank.org/ (accessed on 5th of december, 2021). https://www.riotinto.com/news/releases/2020/rio-tinto-declares-maiden-ore-reserve-at-jadar https://www.riotinto.com/news/releases/2020/rio-tinto-declares-maiden-ore-reserve-at-jadar https://minexconsulting.com/industry-spotlight-on-the-western-tethyan/ https://cqegheiulaval.com/facing-the-global-challenges-in-mining-activities-adoption-of-legislation-and-mining-policies-in-albania/ https://cqegheiulaval.com/facing-the-global-challenges-in-mining-activities-adoption-of-legislation-and-mining-policies-in-albania/ https://www.worldbank.org/ g eo lo gi a c ro at ic a geologia croatica 75/special issue 330 appendix 1. primary mineral deposits of the adria region in the exploration phase (based on the west balkan mineral register, 2021). ud: under development, f: feasibility, pa: pending approval, constr.: construction; *no records at the west balkan mineral register location is not accurate. numbering mines (inspire) greenfields (inspire) municipality lat. wgs 84 (inspire) lon. wgs 84 (inspire) commodity group (inspire) metal (inspire) minor metal (symbol) deposit class (inspire) current status (inspire) type of deposit (inspire) 1' strelci kičevo 41.5280 21.0136 molybdenum ore, iron and ferro-alloys metals mo cu, fe, mn a f graniticigneousrocksandpegmatites 2' rakle prilep 41.4180 21.7426 iron-nickel ore, iron and ferro-alloys metals fe, ni co, cr a f laterite 3' kazan dol valandovo, bogdanci, dojran 41.2607 22.5725 copper ore, base metals cu pb, zn, cd, as, sb, se, te, w, mo, bi, sn a constr. veinpolymetallic 4' ilovica bosilovo, novo selo 41.4825 22.8427 copper ore, base metals cu, au ag, mo a pa, constr. porphyry 5' borov dol konče, štip 41.6009 22.3354 copper ore, base metals cu, au, ag fe, mn, mo a constr. porphyry 6' kadiica pehčevo 41.8073 22.9084 copper ore, base metals cu fe, mn, mo a constr. porphyry 7' plavica and crn vrv kratovo, probištip 42.0449 22.1761 copper ore, base metals cu, ag, au pb, zn a pa, constr. porphyry 1 çiflig korçë 40.4815 20.6138 copper ore, base metals cu c f mafictoultramaficeffusivevolcanism 2 liqeni i kuq librazhd 41.1142 20.3270 iron-nickel ore, iron and ferro-alloys metals fe c f laterite 3 babe barajevo, sopot, voždovac 44.5356 20.5248 lead-zinc ore, base metals pb, zn, ag fe, cu, as unknown ud polymetallicmanto 4 perlati jugor mirditë 41.7243 19.9915 copper ore, base metals cu b f mafictoultramaficeffusivevolcanism 5 butmi lezhë 41.8733 19.8034 titanium-magnetite ore, special and rare metals ti b f nonorganic 6 sukaxhi lezhë 41.9061 19.8712 titanium-magnetite ore, special and rare metals ti b f nonorganic 7 tuçi lindor fushë arrëz 42.0335 20.1070 copper ore, base metals cu au β f mafictoultramaficeffusivevolcanism 8 nikoliq 2 has 42.2347 20.4264 copper ore, base metals cu c f mafictoultramaficeffusivevolcanism 9 bregu bibes tropojë 42.3115 20.2528 pge, precious metals pt pt d f ophiolite 10 stogovo debar, centar župa, kičevo, struga, debarca 41.4301 20.6722 mangenese ore, iron and ferro-alloys metals mn ni, co, cr, fe, mn c f sedimentarymanganese 11 tajmište kičevo, mavrovo and rostuše 41.6192 20.8178 iron ore (carbonate), iron and ferro-alloys metals fe d ud bandedironformation 12 studena voda kavadarci 41.1562 21.9861 iron-nickel ore, iron and ferro-alloys metals fe, ni co, cr d f laterite 13 konjsko (javorak) nikšić 42.5942 19.2174 aluminium (bauxite ore), base metals al df bauxite 14 bašibos valandovo 41.3028 22.7137 lead-zinc ore, base metals pb, zn cu, ag, bi, au b f veinpolymetallic 15 iberli demir kapija 41.4770 22.3251 iron ore, iron and ferro-alloys metals fe, zn, cu mn, ag, w, be, bi, cd, sr d f skarnandcarbonatereplacement 16 mitrašinci berovo 41.7408 22.6862 titanium-iron ore, special and rare metals ti, fe ni, v unknown f mafictoultramaficintrusion 17 pehčevo pehčevo 41.7705 22.9178 iron ore, iron and ferro-alloys metals fe mn, cu, pb, zn, al, ti d f shorelineormarineplacer 18 jamište probištip 42.0600 22.2796 lead-zinc ore, base metals pb, zn cu, au, cd b f polymetallicmanto 19 blizanci probištip 42.0529 22.2172 lead-zinc ore, base metals pb, zn cu, mn b f veinpolymetallic 20 petrošnica staro nagoričane 42.2195 21.9759 molybdenum copper gold ore, iron and ferro-alloys metals mo, cu, au, ag sb, zn, pb, ba, sn unknown f g eologia c roatica borojević šoštarić et al.: the future of mining in the adria region: current status, swot and gap analysis of the mineral sector 331 numbering mines (inspire) greenfields (inspire) municipality lat. wgs 84 (inspire) lon. wgs 84 (inspire) commodity group (inspire) metal (inspire) minor metal (symbol) deposit class (inspire) current status (inspire) type of deposit (inspire) 21 konjsko gevgelija, kavadarci 41.1905 22.2609 copper ore, base metals cu, au, ag zn, as, sb unknown f polymetallicmanto 22 međugorje nikšić 42.6365 19.2278 aluminium (bauxite ore), base metals al df bauxite 23 međeđe nikšić 42.7140 18.9296 aluminium (bauxite ore), base metals al fe d f bauxite 24 đelov do nikšić 42.7143 18.6999 aluminium (bauxite ore), base metals al fe, ti, si d f bauxite 25 laz nikšić 42.7608 19.0303 aluminium (bauxite ore), base metals al fe, ti, si df bauxite 26 strašnica nikšić 42.8525 19.0557 aluminium (bauxite ore), base metals al fe, ti, si df bauxite 27 bršno (raline) niksic 42.7258 19.0244 aluminium (bauxite ore), base metals al fe, ti, si d f bauxite 28 crvenjaci niksic 42.7004 19.1399 aluminium (bauxite ore), base metals al fe, ti, si d f bauxite 29 strmošne bare (sjekrica) berane 42.7203 19.8976 lead-zinc ore, base metals pb,zn cu c f polymetallicmanto 30 brskovo mojkovac 42.9500 19.6258 lead-zinc ore, base metals pb,zn cu b ud polymetallicmanto 31 igrišta mojkovac 42.9598 19.6227 lead-zinc ore, base metals pb, zn cu b f polymetallicmanto 32 varine pljevlja 43.1775 19.3832 copper ore, base metals cu cu b f maficvolcanismmassivesulphide 33 đurđeve vode pljevlja 43.3747 19.0440 lead-zinc ore, base metals pb, zn cu b f polymetallicmanto 34 paljevine pljevlja 43.3710 19.0500 lead-zinc ore, base metals pb,zn cu c f polymetallicmanto 35 ribnik pljevlja 43.3691 19.0598 lead-zinc ore, base metals pb,zn cu c f polymetallicmanto 36 vranje* vranje 42.9400 21.2627 borates-lithium ore, minerals for chemical use unknown ud 37 viti* viti 43.0887 20.9237 borates-lithium ore, minerals for chemical use unknown ud 38 piskanja raška 43.3793 20.6474 borates, minerals for chemical use unknown ud nonorganic 39 jadar loznica 44.5268 19.3541 borates-lithium ore, minerals for chemical use li unknown ud nonorganic 40 valjevo* valjevo 44.4557 20.4716 borates-lithium ore, minerals for chemical use unknown ud 41 babje librazhd 41.1591 20.3098 gold ore, precious metals au unknown f orogenicgold 42 rekovac* rekovac 43.9180 20.9202 borates-lithium ore, minerals for chemical use unknown ud 43 bigar hill žagubica and majdanpek 44.2354 21.8816 gold ore, precious metals au unknown ud carlintypecarbonatehosted 44 korkan bor and žagubica 44.2543 21.8894 gold ore, precious metals au unknown ud carlintypecarbonatehosted 45 bakovici fojnica 43.9398 17.9296 gold ore, precious metals au ag c ud orogenicgold 46 rupice vareš 44.1927 18.2393 lead-zinc ore, base metals pb, zn, ag, au cu, sb, hg b ud shalehosted 47 veovaca vareš 44.1509 18.3625 lead-zinc ore, base metals pb,zn ag, hg c ud shalehosted 48 vitlovac srebrenica 44.1170 19.3080 lead ore, base metals pb, zn cd, ag, sn, sb, s, mn b constr. polymetallicmanto 49 kazani srebrenica 44.1130 19.2870 lead ore, base metals pb, zn cd, ag, sn, sb, s, mn b constr. polymetallicmanto 50 lopare* lopare 44.6024 18.8159 borates, minerals for chemical use unknown ud 51 oštrelj sanski most 44.7591 16.3149 aluminium (bauxite ore), base metals al dpa bauxite appendix 1. continued. g eo lo gi a c ro at ic a geologia croatica 75/special issue 332 appendix 2. primary mineral deposits of the adria region in the exploitation phase (based on the west balkan mineral register, 2021). legend: o: operating, oi: operating intermittently, oc: operating continuously. numbering mines (inspire) greenfields (inspire) municipality lat. wgs 84 (inspire) lon. wgs 84 (inspire) commodity group (inspire) metal (inspire) minor metal (symbol) deposit class (inspire) current status (inspire) type of deposit (inspire) 1' bučim radoviš, štip 41.6617 22.3506 copper ore, base metals cu, au, ag fe, mn, mo, bi, se, pd, ti a oc porphyry 2' sasa makedonska kamenica 42.1267 22.5066 lead-zinc ore, base metals pb, zn, ag ag, cd, in, co, bi, cu, sb a oc skarnandcarbonatereplacement 3' šuplja stijena pljevlja 43.3801 19.0440 lead-zinc ore, base metals pb, zn cu a o polymetallicmanto 4' veliki krivelj bor 44.1236 22.1139 copper ore, base metals cu, fe cu a o porphyry 5' bor jama bor 44.0894 22.1006 copper ore, base metals cu, au fe, au a o highsulphidation 6' majdanpek s. revir majdanpek 44.4254 21.9239 copper ore, base metals cu, au se, pge, ag, cd (recoverable) a o porphyry 7' majdanpek n. revir majdanpek 44.4107 21.9319 copper ore, base metals cu, au se, pge, ag, cd (recoverable) a o porphyry 8' očekalj prgoševo olovo 44.0953 18.6036 lead ore, base metals pb a oc carbonatehosted 1 kapshticë devoll 40.6098 21.0218 iron-nickel ore, iron and ferro-alloys metals fe d o laterite 2 bitinckë devoll 40.6372 20.9913 iron-nickel ore, iron and ferro-alloys metals fe co c o laterite 3 debrovë pogradec 40.9916 20.4644 iron-nickel ore, iron and ferro-alloys metals fe co d o laterite 4 katjel prenjas 41.0376 20.5668 chrome ore, iron and ferro-alloys metals cr2o3 d o ophiolite 5 skroskë prrenjas 41.1073 20.4944 iron-nickel ore, iron and ferro-alloys metals fe co c o laterite 6 batër bulqizë 41.4586 20.2369 chrome ore, iron and ferro-alloys metals cr2o3 d o ophiolite 7 bulqizë bulqizë 41.4786 20.2247 chrome ore, iron and ferro-alloys metals cr2o3 d o ophiolite 8 krastë bulqizë 41.4301 20.2203 chrome ore, iron and ferro-alloys metals cr2o3 d o ophiolite 9 thekën bulqizë 41.4202 20.2902 chrome ore, iron and ferro-alloys metals cr2o3 d o ophiolite 11 batër bulqizë 41.4539 20.2347 chrome ore, iron and ferro-alloys metals cr2o3 d o ophiolite 11 qafë bulli peshkopi 41.4771 20.1988 chrome ore, iron and ferro-alloys metals cr2o3 c o ophiolite 12 spaç mirditë 41.9010 20.0554 copper ore, base metals cu au b o mafictoultramaficeffusivevolcanism 13 gurth (plakez) mirditë 41.9182 20.0690 copper ore, base metals cu c o mafictoultramaficintrusion 14 munellë fushë arrëz 41.9737 20.0815 copper ore, base metals cu zn, pb, au, ag b o mafictoultramaficeffusivevolcanism 15 qafë bari fushë arrëz 41.9972 20.0753 copper ore, base metals cu au c o mafictoultramaficeffusivevolcanism 16 mamëz kukës 42.0550 20.3777 nickel ore, iron and ferro-alloys metals ni c o laterite 17 kalimash 1 tr 7 kukës 42.0524 20.2741 chrome ore, iron and ferro-alloys metals cr2o3 c o ophiolite 18 kalimash 2 tr 1 kukës 42.0562 20.2995 chrome ore, iron and ferro-alloys metals cr2o3 c o ophiolite g eologia c roatica borojević šoštarić et al.: the future of mining in the adria region: current status, swot and gap analysis of the mineral sector 333 numbering mines (inspire) greenfields (inspire) municipality lat. wgs 84 (inspire) lon. wgs 84 (inspire) commodity group (inspire) metal (inspire) minor metal (symbol) deposit class (inspire) current status (inspire) type of deposit (inspire) 19 kalimash 3 tr. 6, 6a,a kukës 42.0469 20.3069 chrome ore, iron and ferro-alloys metals cr2o3 d o ophiolite 20 trull kukës 42.0215 20.3381 iron-nickel ore, iron and ferro-alloys metals fe co d o laterite 21 kodra e trullit kukës 42.0165 20.3230 iron-nickel ore, iron and ferro-alloys metals fe co d o laterite 22 vlahën has 42.2320 20.4782 chrome ore, iron and ferro-alloys metals cr2o3 d o ophiolite 23 zogaj 3 tropojë 42.3040 20.3005 chrome ore, iron and ferro-alloys metals cr2o3 d o ophiolite 24 kosovrasti debar 41.5255 20.5635 gypsum, building raw materials c oc evaporite 25 groot veles 41.7374 21.7231 iron-nickel ore, iron and ferro-alloys metals fe, ni co d oc laterite 26 hamzali bosilovo 41.5199 22.7696 feldspathic raw material (ceramics), ceramic and refractory minerals c oc graniticigneousrocksandpegmatites 27 zletovo probištip, kratovo 42.0332 22.2052 lead zinc ore, base metals pb, zn, ag ag, cd, cu, in, ga, au b oc veinpolymetallic 28 toranica kriva palanka, makedonska kamenica 42.1593 22.4915 lead-zinc ore, base metals pb, zn, ag fe, cu, as, bi, mn b oc skarnandcarbonatereplacement 29 durakov do i niksic 42.7623 19.1618 aluminium (bauxite ore), base metals al fe, ti, si d o bauxite 30 biočki stan niksic 42.7532 19.1678 aluminium (bauxite ore), base metals al fe, ti, si d o bauxite 31 štitovo ii niksic 42.7352 19.1735 aluminium (bauxite ore), base metals al fe, ti, si d o bauxite 32 zagrad niksic 42.7631 19.0861 aluminium (bauxite ore), base metals al fe, ti, si d o bauxite 33 podvirovi bosilegrad 42.3509 22.3360 lead-zinc ore, base metals pb, zn fe, mn, au, as c o polymetallicmanto 34 grot blagodat vranje 42.5294 22.2387 lead-zinc ore, base metals zn, pb, ag cd, cu, au, as c o skarnandcarbonatereplacement 35 korminjoš vranje 42.5056 21.9150 zeolites, minerals for chemical use unknown o nonorganic 36 lece medveđa 42.8876 21.5832 lead-zinc ore, base metals pb, zn fe, au b o polymetallicmanto 37 igroš vidojevići brus 43.3691 21.1026 zeolites, minerals for chemical use unknown o nonorganic 38 belo brdo leposavić 43.2526 20.8493 lead-zinc ore, base metals pb, zn, fe as, cu b o skarnandcarbonatereplacement 39 pobrđe raška 43.3950 20.6149 borates, minerals for chemical use unknown o nonorganic 40 krive strane i torine čajetina 43.6982 19.6700 magnesite, minerals for chemical use mg unknown o ophiolite 41 ribnica čajetina 43.6924 19.6136 magnesite, minerals for chemical use mg unknown o ophiolite 42 brezak čačak 43.9903 20.2152 magnesite, minerals for chemical use mg unknown o ophiolite 43 wider locality of čačak čačak 43.9933 20.3059 magnesite, minerals for chemical use mg unknown o ophiolite 44 rudnik gornji milanovac 44.1176 20.5198 lead-zinc ore, base metals pb, zn fe, cu, as b o skarnandcarbonatereplacement 45 garasi aranđelovac 44.3058 20.4720 clays (kaolinite), ceramic and refractory minerals unknown o laterite 46 veliki majdan ljubovija 44.3040 19.3001 lead-zinc ore, base metals pb, zn fe, cu, as c o polymetallicmanto 47 kranjani valjevo 44.4467 19.6513 clays (kaolinite), ceramic and refractory minerals unknown o shorelineormarineplacer appendix 2. continued. g eo lo gi a c ro at ic a geologia croatica 75/special issue 334 numbering mines (inspire) greenfields (inspire) municipality lat. wgs 84 (inspire) lon. wgs 84 (inspire) commodity group (inspire) metal (inspire) minor metal (symbol) deposit class (inspire) current status (inspire) type of deposit (inspire) 48 beli majdan loznica 44.5764 19.3516 clays (kaolinite), ceramic and refractory minerals unknown o laterite 49 tenka 1,2 north revir majdanpek 44.4314 21.9175 lead-zinc ore, base metals zn, cu fe, pb, au, ag b o polymetallicmanto 50 crveni pijesci-pleće trebinje 42.8670 18.2910 aluminium (bauxite ore), base metals al al d o laterite 51 jasenjani mostar 43.1322 17.7585 aluminium (bauxite ore), base metals al doi bauxite 52 široki brijeg široki brijeg 43.4334 17.5961 aluminium (bauxite ore), base metals al fe, ti, si doc bauxite 53 cerovi doci posušje 43.4701 17.5268 aluminium (bauxite ore), base metals al fe, ti doi bauxite 54 vučipoljetribistovo posušje 43.4790 17.5133 aluminium (bauxite ore), base metals al doi bauxite 55 crne lokve gnjat široki brijeg 43.4402 17.4803 aluminium (bauxite ore), base metals al fe, ti doc bauxite 56 sobač tribistovo posušje 43.4889 17.3881 aluminium (bauxite ore), base metals al fe, ti, si doi bauxite 57 mratnjača posušje 43.5054 17.4132 aluminium (bauxite ore), base metals al fe, ti doc bauxite 58 volujak-kadim posušje 43.5142 17.1950 aluminium (bauxite ore), base metals al unknown oi bauxite 59 studena vrila zagorje posušje 43.5438 17.2188 aluminium (bauxite ore), base metals al fe, ti, si doc bauxite 60 kosturi srebrenica 44.0480 19.2570 aluminium (bauxite ore), base metals al fe, ti b o laterite 61 srebrenicasase srebrenica 44.1180 19.3530 lead ore, base metals pb, zn cd, ag, sn, sb, s, mn b o polymetallicmanto 62 braćan milići 44.0890 19.1520 aluminium (bauxite ore), base metals al fe, ti, si b o laterite 63 crvene stijene milići 44.1000 19.1310 aluminium (bauxite ore), base metals al al b o laterite 64 tuzla* tuzla 44.537 18.6732 salt, fertilizer minerals uknown o unkown 65 bešpelj jablanica 44.4231 17.3531 aluminium (bauxite ore), base metals al fe, ti doc bauxite 66 crvene stijene jajce 44.4040 17.3690 aluminium (bauxite ore), base metals al fe, ti doc bauxite 67 poljane jajce 44.3802 17.3883 aluminium (bauxite ore), base metals al fe, ti, si doc bauxite 68 dočići šipovo 44.2920 17.1180 gypsum, building raw materials caso4 b oi unkown 69 sokolac šipovo 44.2860 17.0160 clays (bentonite), specialty and other industrial rocks and minerals b o layeredcomplex 70 gradina baraći 44.3100 16.9540 aluminium (bauxite ore), base metals al fe, ti, si b o laterite 71 bojište sanski most 44.7026 16.4938 aluminium (bauxite ore), base metals al doi bauxite 72 ljubija prijedor 44.8670 16.8940 iron ore, iron and ferro-alloys metals fe si, ba, pb, zn, ca, mn b o bandedironformation 73 petkovac novi grad 45.0520 16.5020 gypsum, building raw materials caso4 b o unkown 74 popović polje bužim 45.1143 16.0375 mangenese ore, iron and ferro-alloys metals mn c oi sedimentarymanganese 75 kobaš srbac 45.1080 17.7170 clays (kaolinite), ceramic and refractory minerals b o layeredcomplex 76 ston* ston 42.8383 17.6963 salt, fertilizer minerals uknown o unkown 77 nin* nin 44.2423 15.1834 salt, fertilizer minerals uknown o unkown 78 pag* stara novalja 44.4434 15.0553 salt, fertilizer minerals uknown o unkown 79 rovinj rovinj 45.1080 13.6440 aluminium (bauxite ore), base metals al fe, ti unknown o bauxite appendix 2. continued. 2024 | 77/1 | 1–14 | 13 figs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction as one of the most important orogenic events of the late palaeozoic, the variscan orogeny had a major influence on the sedimentation and structural configuration of the various tectonostratigraphic units and terranes in the present-day circum-pannonian region. the spatial occurrence of terranes as fault-bounded crustal units comprising rock sequences of regional extent with distinctive geological history (coney et al., 1980) does not necessarily reflect their relative position prior to their assembly (chetty, 2017). in this respect, the adria-dinaria megaterrane, as one of the megaterranes in the circum-pannonian region, belonged to the passive margin of gondwana and has moved northwards from the late carboniferous to the present day (karamata, 2006; vozárová et al., 2009). this megaterrane com prises pre-mesozoic sequences deposited on the passive margin of gondwana (e.g., ramovš et al., 1990) and mesozoic carbonates formed on the adriatic carbonate platform (vlahović et al., 2005), which were later subjected to compression, rotation and transcurrent displacement during the alpine orogeny ( karamata, 2006). the adria-dinaria stratigraphic sequences are best exposed in the dinarides and in the southern alps (vozárová et al., 2009). upper palaeozoic rocks in the external dinarides of southern croatia are best exposed in the area of lika and velebit mt. (fig. 1; sremac & kochansky-devidé, 1982 and references therein). the core of the velebit mt. anticline comprises a lower permian košna conglomerates of the velebit mt. (croatia): modal composition, provenance and depositional environment iva palatinuš1,2, katarina gobo*,1, karmen fio firi1, frane marković1 and jasenka sremac1 1 university of zagreb, faculty of science, department of geology, horvatovac 102b, 10 000 zagreb, croatia; (*corresponding author: katarina.gobo@geol.pmf.unizg.hr) 2 croatian geological survey, department of mineral resources, sachsova 2, 10 000 zagreb, croatia doi: 10.4154/gc.2024.02 abstract the multicoloured ‘košna’ conglomerates are investigated in the area of the košna voda spring, in the brušane area of velebit mt., croatia. the studied conglomerates consist of red-coloured matrix and clasts of various lithologies (sandstones, limestones, chert and quartz pebbles) and sizes, suggesting provenance from different areas. average clast size and their percentage was determined by the udden-wentworth classification with estimation of the matrix content. clasts and matrix lithological and mineralogical characteristics were determined using petrographic, ore microscopy, and x-ray diffraction analysis. sandstone clasts in the studied conglomerates are classified as lithic arenites, subarkoses and arkoses. limestone clasts are mostly wackestones to packstones with foraminifera, ostracods, echinoid and bryozoan fragments that derive from late carboniferous/early permian shallow-marine limestones. calcispheres and incipient growth forms of microcodium are also present, suggesting different sediment sources and resedimentation processes. fragments of fusulinid foraminifera were identified in the matrix of the ‘košna’ conglomerates. based on the analyses performed, and field observations, the ‘košna’ conglomerates are described as early permian (cisuralian) polymictic clast-supported to matrix-supported conglomerates and breccia-conglomerates that share structural and textural similarities with conglomerates from other areas in the dinarides, as well as in the eastern and southern alps. the ‘košna’ conglomerates are younger than the sakmarian and are comparable with the trogkofel limestones of the carnic alps and the karavanke mts. in slovenia. we suggest that the studied deposits originated from the uplifted variscan mountains during the variscan and saalian orogenic movements, and were finally deposited from tractive flows and occasional debris flows in a shallow marine environment of the palaeo-tethys, possibly in fan deltas. succession of clastic and carbonate deposits. these deposits range in age from the pennsylvanian (moscovian) until the end of permian/beginning of the triassic, with an unconformable or tectonic contact separating carboniferous from permian deposits (kochansky-devidé, 1973; aljinović & sremac, 1997). they were deposited on the palaeotethyan shelf area along the northern passive continental margin of gondwana (ramovš et al., 1990; sremac, 2005). geological studies of the palaeozoic deposits in the area of lika and velebit mt. were initiated by foetterle (1855), hauer (1868), schubert (1908, 1910) and koch (1909a,b, 1914, 1929a,b), with further research by salopek (1937, 1938, 1939, 1940, 1941, 1942, 1948, 1952). stratigraphic subdivision of the permian deposits based on microfossils was presented by kochansky-devidé (1955, 1959, 1965, 1973). petrological description of the upper palaeozoic deposits of the lika and velebit mt. area, as well as their tectonic evolution, was provided by raffaelli and šćavničar (1968). biostratigraphic determinations, depositional environments and climatic conditions during deposition of the palaeozoic deposits in the velebit mt. area are presented in papers by tišljar et al. (1991) and sremac (1991, 2005, 2007, 2012). recent papers by werner et al. (2015) and sudar et al. (2016) focused on remagnetization phenomena of the lower permian clastics and the composition and provenance of middle permian sandstones respectively, in the study area. previous research was less focused on the age and depositional environment of clastic deposits, especially the ‘košna’ conarticle history: manuscript recieved: july 18, 2023 revised manuscript accepted: december 14, 2023 available online: february 27, 2024 keywords: polymictic conglomerates, brušane area, velebit mt., variscan orogeny, cisuralian g eo lo gi a c ro at ic a geologia croatica 77/12 glomerates, which have been assigned to the middle permian by salopek (1942) or early permian by kochansky-devidé (1973). these conglomerates form part of a 750 m thick succession known as the ‘košna beds’ which were named after the košna voda spring in the brušane area of velebit mt. (salopek, 1942). the košna beds consist of breccia or green pyritic sandstones in the basal part, and are overlain by quartz conglomerates, ‘košna’ conglomerates with limestone and clastic pebbles, and red to yellow ‘košna’ sandstones (salopek, 1942, 1948; kochansky-devidé, 1973). the ‘košna beds’ are conside red as an equivalent of the trogkofel beds in slovenia (kochansky devidé, 1973) and were petrologically studied by rafaelli & šćavničar (1968), who determined that the occurrence of lithic greywackes and texturally immature sediment was indicative of orogenic movements. upper palaeozoic clastic successions in the area of the southern alps were extensively studied and interpreted in terms of depositional environment, stratigraphy and origin (ramovš & kochansky-devidé, 1965; ramovš, 1968; krainer, 1990, 1993, 2005; cassinis et al., 2008; vozárová et al., 2009; schaffhauser et al., 2015). in contrast, the upper palaeozoic clastic deposits in the area of lika and gorski kotar in croatia have been studied in detail only in terms of their lithological composition (aljinović & sremac, 1997), whilst their origin and depositional environment are still not fully understood. therefore, the aim of this paper is to determine the age, origin, climatic conditions during weathering and the depositional environment of the ‘košna’ conglomerates based on the data obtained by field research and qualitative and quantitative analyses. due to the similar tectono-sedimentary development of the late palaeozoic successions in the adria-dinaria megaterrane (vozárová et al., 2009), the ‘košna’ conglomerates will be compared with similar deposits in croatia, slovenia, and the eastern and southern alps. 2. geological setting and description of the studied area the research area is situated in the central part of the velebit mountain, northwest of brušane village (lika–senj county), in the vicinity of the košna voda spring (fig. 1). the oldest deposits here are upper carboniferous shales, sandstones and conglomerates, with limestone lenses occurring in the uppermost part of this clastic succession (salopek, 1942; sokač et al., 1976; kochansky-devidé, 1979). this upper carboniferous succession is considered to be an equivalent of the auernig beds (salopek, 1942; sokač et al., 1976; kochansky-devidé, 1973). the end of the carboniferous and the beginning of the permian are characterized by rattendorf limestones with schwagerina and pseudoschwagerina fossils (sremac & kochansky-devidé, 1982; cleal et al., 2015). the contact between the auernig group and the rattendorf limestones is marked by the occurrence of lithic greywackes and coarse-grained terrigenous clasts, indicating orogenic movements that caused infilling of the sedimentary basin with coarse and immature sediment (raffaelli & šćavničar, 1968; kochansky-devidé, 1973). the ‘košna’ conglomerates in the studied area are locally in either a transgressive contact with the underlying carboniferous deposits, or intercalated with permian clastics (salopek, 1942; sokač et al., 1976). the permian deposits in the area of brušane – baške oštarije can generally be subdivided into the lower, clastic zone (including the ‘košna’ conglomerates) and the upper, dolomite zone, with three limestone intervals (sremac & kochansky-devidé, 1982). the change in the lithological composition is the result of significant orogenic activity associated with the late stages of the variscan orogeny in the middle permian and at the beginning of the late permian (salopek, 1942, 1948; raffaelli & šćavničar, 1968; kochansky-devidé, 1973). 3. methods this research included detailed field investigations in the area of the košna voda spring in the jažine trench (fig. 1), where conglomerates occur as scattered and discontinuous outcrops. a total of 19 rock samples, which included limestone, chert and sandstone clasts, as well as košna conglomerate fragments of different size and composition, were randomly selected, sampled and marked with the letter „k“ and numbers 1 to 19. five well exposed layers were photographed within 60 x 40 cm frames in order to measure the longest (x) and shortest (z) visible clast axes (fig. 2), determine average clast size and categorize them according to the udden-wentworth scale for statistical processing of granulometric data. the matrix percentage was estimated according to terry & chilingar (1955). figure 1. location and geological map of the studied area (modified after salopek, 1942, 1948). g eologia c roatica palatinuš et al.: lower permian košna conglomerates of the velebit mt. (croatia): modal composition, provenance and depositional environment 3 petrological analyses of conglomerate clasts and matrix were undertaken at the department of geology of the faculty of science, university of zagreb. from the 19 samples, 23 thin-sections were prepared according to the method described in vrkljan et al. (2018). out of these, 17 were thin-sections of sandstones, five of limestones and one of chert. thin-sections were analyzed using a petrographic polarizing microscope and an ore microscope. from 17 thin-sections and six polished sections of sandstones, representative samples were analyzed using the line counting method, and classified according to pettijohn et al. (1987). six selected thin-sections of sandstones were stained using a mixture of alizarin red s and potassium ferricyanide dissolved in a dilute hydrochloric acid solution in order to differentiate the carbonate minerals (dickson, 1966; evamy, 1969). identified minerals and lithic fragments in photomicrographs, photographed with and without crossed polars, are annotated with abbreviations according to whitney & evans (2010) and swanson (1981). to determine the possible provenance of the clastic material, a ternary provenance diagram (modified after dickinson et al., 1983) was used together with the weathering index diagram (after weltje, 1994; weltje et al., 1998), to determine the relief, weathering conditions and origin of the clastic material. micropalaeontological analyses were conducted on five limestone samples and classified according to folk (1959) and dunham (1962). x-ray powder diffraction analysis was performed on the conglomerate matrix to determine its mineralogical composition and relate it to the specific red colouration. the matrix was extracted from two conglomerate samples and analyzed in a philips x’pert pro diffractometer. the samples were continuously scanned (0,001° 2θ/s) with the generator set to 40 ma and 40 kv, using a copper anode. diffractograms were interpreted using the x’pert highscore plus program and the pdf-2 database (icdd 2004). 4. results 4.1. fieldwork the studied conglomerates crop out as an approximately 2 km wide lens-shaped body, reach a maximum thickness of about 100 m and are fragmented and scattered along the košna voda creek (fig. 3a). they comprise pebbleand cobble-sized clasts of various lithological composition: red, grey and green pyritic sandstones, chert, limestone and quartz. the matrix is composed of mostly red, coarse sand-sized particles. the conglomerates are predominantly clast-supported, massive and poorly sorted, with rounded to subrounded clasts of low sphericity. pebble imbrication is also common, as well as intervals exhibiting normal grading and crude plane-parallel stratification (fig. 3b). subordinate matrix-supported conglomerates contain clasts of different sphericity and roundness. in several places, angular clasts prevail and these deposits can be classified as breccia-conglomerates. elsewhere, conglomerates intercalate with horizontally laminated sandstones (fig. 3c). 4.2. quantitative analysis from photographs of five selected 60 by 40 cm frames placed on the outcrop (fig. 2), the length of clast xand z-axes were measured, for a total of 609 clasts. the length of the longest axis (x) ranges from 0.7 to 10.5 cm with an average of 2.7 cm, while the length of the shortest axis (z) ranges from 0.4 to 7.3 cm with an average of 1.5 cm. based on the measured diameters, using the udden-wentworth grain size classification, clasts are divided into two categories: pebbles (4–64 mm) and cobbles (64–256 mm). the pebbles dominate with 96.40 % (fig. 4a) and are further divided into three subcategories (fig. 4b): medium (8–16 mm), coarse (16–32 mm) and very coarse (32–64 mm). most pebbles are very coarse (54 %), whereas subordinate medium and coarse pebbles are equally represented. the amount of matrix varies from 5 % in clast-supported conglomerates to up to 80 % in matrix-supported conglomerates. 4.3. petrology of sandstones, provenance and weathering index diagram sandstone clasts, determined in 17 out of 23 thin-sections, are lithic arenites, subarkoses and arkoses, with their characteristics described and explained below. 4.3.1. lithic arenites lithic arenites (fig. 5a to h) are poorly to well-sorted with subangular to sub-rounded grey, yellowish and brownish grains in figure 2. example of the 60 by 40 cm frame used to measure x and z clast axes. g eo lo gi a c ro at ic a geologia croatica 77/14 a dark to reddish matrix (fig. 5b, d, f) that contains silt-sized brownish to grey particles about 60 μm in size. the rest of the bounding material is cement, composed of ferruginous dolomite. quartz grains are most common (48–53.5 %; fig. 5a–f), often interspersed with calcite veins. lithic fragments make up about 25.7–30 % of the samples, while feldspar grains are present at about 21 % (fig. 5a, b). among the lithic fragments, chert is the most common type (fig. 5a–d), whereas limestone clasts, lowmetamorphic rock fragments and unidentifiable fine-grained reddish rock fragments are less common. besides the main rockforming minerals, elongated mica grains are also present, as well as small amounts of idiomorphic opaque minerals showing cubic symmetry (fig. 5g, h). to identify the opaque minerals, two polished sections were made. in reflected light, the colour of these minerals is brassy yellow with a metallic lustre, which is, along with the habitus, characteristic for pyrite (fig. 5g, h). the x-ray powder diffraction analysis showed the presence of quartz, haematite, muscovite and calcite in sample k-1 (fig. 6a), whereas sample k-6 additionally shows the presence of clinochlore and feldspar (fig. 6b). 4.3.2. subarkoses samples of subarkoses (fig. 7a to f) are moderatelyto wellsorted and contain angular to subangular grains. compositionally, quartz grains prevail (up to 66 %), while feldspars and lithic fragments make up to 22.4 % and 16.8 % of the samples, respectively. the cement is composed of ferruginous dolomite. lithic fragments comprise chert, limestones, metamorphic rock clasts and microbreccia fragments (fig. 7a, c). mica and opaque mineral grains are rare. chlorite minerals occupy up to 5 % of the samples. chlorite grains are green and anhedral with an average size of 120 μm (fig. 7e). the interference colour is lavender-blue to purple (fig. 7f), which is characteristic for chlorite minerals rich in iron. 4.3.3. arkose one sample is classified as a moderately sorted arkose (fig. 8), with 62.2 % of quartz, 29.5 % of feldspar and 8% of lithic fragments – mostly limestone, rare chert and small amounts of plagioclase and mica (fig. 8a, b). cement is present in small amounts and is composed of ferruginous dolomite. 4.3.4. provenance diagram and weathering index diagram the ternary provenance diagram by dickinson et al. (1983) shows that samples of lithic arenites (k-1, k-6 and k-11) and subarkoses (k-4 and k-12) are all plotted in the area of recycled orogen, while the arkose sample (k-13) plots at the borderline of two areas: recycled orogen and continental block (fig. 9). figure 3. the sedimentary features of the ‘košna’ conglomerates. a: outcrop in the vicinity of the košna voda spring, with visible massive matrix-supported conglomerates. person is 1.70 m tall. b: close-up photo showing a clast-supported conglomerate with normal grading and crude plane-parallel stratification. hammer is 30 cm long. c: horizontally laminated sandstone. coin for scale is 24.5 mm in diameter. figure 4. results of statistical analyses obtained from gravel clast axes measurements of 609 clasts from the ‘košna’ conglomerates. a: pie chart showing the dominance of pebble-sized clasts. b: pie chart showing the relative proportions of the various pebble categories. g eologia c roatica palatinuš et al.: lower permian košna conglomerates of the velebit mt. (croatia): modal composition, provenance and depositional environment 5 the weathering index diagram (weltje, 1994; weltje et al., 1998) consists of two areas indicating the origin of the weathered material (metamorphic/sedimentary or plutonic). these areas are divided into four fields, each indicating relief and climate conditions. the natural logarithm of quartz to lithic fragments ratio and the natural logarithm of quartz to feldspar ratio are plotted on the abscissa and ordinate, respectively. analyzed samples plotted in the plutonic area of the diagram, with figure 5. photomicrographs of lithic arenites from the ‘košna’ conglomerates, left under polarized light and right with crossed nicols. legend: cht – chert, qz – quartz, fsp – feldspar, mtrx – matrix. a, b: sample k-1. c, d: sample k-6. e, f: sample k-11, with opaque mineral in the centre. g, h: close-up of the opaque mineral (most likely pyrite) in sample k-11. g eo lo gi a c ro at ic a geologia croatica 77/16 lithic arenites in the area “0” and subarkoses and arkose in the area “1” (fig. 10). 4.4. chert petrology sample k-5 is a microcrystalline chert with quartz veins (fig. 11a, b). it contains idiomorphic opaque mineral grains with thin, light-transmitting edges, making their own reddish-brown colour visible. these grains are determined as haematite (fig. 11c, d). additionally, polished sections revealed anhedral grains with a brassy-yellow colour in reflected light and a metallic lustre, which are determined as pyrite (fig. 11e). 4.5. limestone petrology and microfossil analysis limestone clasts within the ‘košna’ conglomerates occur mainly as cobbles. thin-sections from five selected cobbles show that limestones are mostly composed of poorly preserved skeletal fragments and micrite. they are classified as biomicrites (folk, 1959). according to dunham (1962), sample k-14 is classified as wackestone (fig. 12a), samples k-15, k-16 and k-17 as packstones (fig. 12b), and sample k-18 as wackestone to packstone with sparite-filled cavities. fossil content from the analyzed limestones includes ostracods, calcispheres (fig. 12c), possible radiolarians, echinoid spines, foraminifera, and bryozoans (fig. 12d). isodiametric poly hedral elements (crystals/grains), arranged around a hollow central part occur locally and in size and structure, resemble incipient growth forms of microcodium (fig. 12e–f), i.e. organisms of uncertain systematic position. the features, however, do not show radially elongated calcite grains characteristic of classic microcodium “corncob” and “rosette” morphologies. determined foraminifera species include: diplosphaerina (previously: neotuberitina) maljavkini suleymanov, 1948 (fig. 12g); tufigure 6. x-ray diffractograms of matrix samples from the ‘košna’ conglomerates. sample k-1 (above) and k-6 (below). legend: cal – calcite, clc – clinochlore, fsp – feldspar, hem – hematite, ms – muscovite, qz – quartz. g eologia c roatica palatinuš et al.: lower permian košna conglomerates of the velebit mt. (croatia): modal composition, provenance and depositional environment 7 figure 7. photomicrographs of subarkose sample k-4 from the ‘košna’ conglomerates, left under polarized light and right with crossed nicols. legend: cht – chert, qz – quartz, chl – chlorite, pl – plagioclase, or – orthoclase. a, b: fine-grained subarkose. c, d: microbreccia fragment surrounded by finer grains. e, f: chlorite minerals. figure 8. photomicrographs of arkose sample k-13 from the ‘košna’ conglomerates. legend: cal – calcite, ms – muscovite, pl – plagioclase. a: under polarized light and b: with crossed nicols. g eo lo gi a c ro at ic a geologia croatica 77/18 figure 9. ternary provenance diagram modified after dickinson et al. (1983). figure 10. the weathering index diagram modified after weltje (1994) and weltje et al. (1998). g eologia c roatica palatinuš et al.: lower permian košna conglomerates of the velebit mt. (croatia): modal composition, provenance and depositional environment 9 beritina bulbacea galloway & harlton, 1948 (fig. 12h) and turrispiroides cf. microsphaerica k.v. miklukho-maklay, 1968 (fig. 12i). it should be noted that fusulinid foraminiferal fragments are observed in limestones, but also within the sandstone matrix (fig. 12j), together with some unidentified fossil material (fig. 12k). 5. discussion 5.1. sediment source and depositional environment of the ‘košna’ conglomerates the studied deposits in the košna voda spring area include mainly massive, poorly sorted clast-supported conglomerates with very large pebbles (32–64 mm), less common matrix-supported conglomerates and rare breccia-conglomerates. the constituent gravel clasts are by composition sandstones (lithic arenites, subarkoses and arkoses), limestones and cherts. the variations in their shape and size result from their different petrological compositions, as well as from transport and weathering conditions prior to their inclusion into the conglomerates. the matrix is composed of coarse-grained sand particles coloured by haematite. the ternary provenance diagram (dickinson et al., 1983) shows that the analyzed sandstone clasts mostly originated from a recycled orogen and a continental block (fig. 9) and were most likely formed by weathering of a high to moderate relief in a (semi)-arid to partially humid climate, as suggested by the weathering index diagram (fig. 10). the sedimentary textures and structures observed in the conglomerates (plane-parallel stratification, imbrication and normal grading) are common in sediments deposited by tractive flows in alluvial systems and deltas, as well as from coarse-grained turbidity currents (tišljar, 1994). structureless matrix-supported and clast-supported conglomerates may have been deposited from cohesive and cohesionless subaqueous debris flows, respectively (drake, 1990; mulder & alexander, 2001). fragments of fusulinid foraminifera found within the conglomerate matrix suggest deposition in a marine environment. although not found in the studied samples, the occurrence of chlorite minerals, illite and sericite, as well as pyrite in the conglomerate matrix was reported by raffaelli & šćavničar (1968), and is considered as another indication of sedimentation in a marine setting. these results reveal that the sediment constituting the ‘košna’ conglomerates originated from the erosion of the mountains uplifted during the late phases of the variscan orogeny and that they were deposited in shallow marine areas, as firstly suggested by raffaelli & šćavničar (1968). due to limited outcrop exposure, the precise type of depositional environment is difficult to interpret with certainty, but it is suggested that these shallow-marine conglomerates represent gravelly mouth bars or uppermost slope of fan-deltaic or deltaic systems, sourced either by alluvial fans or braided fluvial systems, respectively (nemec & steel, 1984). the limestones – from which the analyzed limestone clasts were derived – most likely formed in a low-energy marine environment, as suggested by the large amount of micrite and presence of ostracods, echinoids and bryozoa (fig. 12a to d). determined calcispheres (fig. 12c) are indicative of deep marine environment; however, in the studied samples they are often found in association with ostracod fragments, suggesting resedimentation processes. the incipient growth forms of microcodium represent a biologically-induced mineralization driven by a saprotrophic microorganism or a microbial association, which is common from the moscovian to the early permian, and appears in calcretes and calcareous palaeosols (esteban, 1972; košir, 2004; kabanov et al., 2008). such types of palaeosols form in subtropical and tropical climatic conditions, with occasional dry periods and well-drained semi-arid soils (kabanov et al., 2008). these figure 11. chert sample k-5. a, b: photomicrographs under polarized light (a) and under crossed nicols (b). c: opaque mineral grains under polarized light and (d) under crossed nicols. e: pyrite grain in polished section under reflected light. g eo lo gi a c ro at ic a geologia croatica 77/110 observations suggest that limestone clasts in the ‘košna’ conglomerates derive from paralic, shallow and deep marine environments, indicating severe tectonic movements (cf. reijmer et al., 2015). taking into account the results of the weathering index diagram obtained from the sandstone clasts (fig. 10; weltje, 1994; weltje et al., 1998), it transpires that the passive margin of gondwana was subjected to an overall semi-arid to partially humid climate, which affected the weathering of both carbonate and clastic successions that sourced the diverse gravel clasts found in the ‘košna’ conglomerates. similar climatic conditions continued during the middle permian, as suggested by the composition and provenance of middle permian sandstones in the nearby pikovac creek valley (fig. 1; sudar et al., 2016). 5.2. age of the ‘košna’ conglomerates limestone clasts from the conglomerates near the košna voda spring comprise microfossils of late carboniferous (gzhelian) to the early permian (asselian, sakmarian) age, suggesting that the conglomerates are younger than the sakmarian (fig. 13). gzhelian to sakmarian rocks are not exposed in the vicinity of the košna voda spring, but microfossils found in the limestone clasts of the ‘košna’ conglomerates are known from the neighbouring regions: e.g. tuberitina bulbacea galloway & harlton, 1928 occurs in the kasimovian−gzhelian deposits of the banovina region (milanović, 1982), early kasimovian limestones (auernig group) of the carnic alps in italy (url3, figure 12. photomicrographs of limestone and sandstone samples from the ‘košna’ conglomerates. a: wackestone, sample k-14; b: packstone with various fossil fragments, sample k-16; c: wackestone with ostracods and calcispheres; d: wackestone to packstone with bryozoan fragment; e–f: wackestone to packstone with microcodium sp.; g: wackestone with diplosphaerina (previously: neotuberitina) maljavkini (suleymanov, 1948); h: tuberitina bulbacea galloway & harlton, 1948 surrounded by microsparite; i: wackestone to packstone with turrispiroides cf. microsphaerica k.v. miklukho-maklay, 1968; j: fragment of fusulinid foraminifera in the sandstone matrix; k: unidentified fossil fragment in the sandstone matrix. g eologia c roatica palatinuš et al.: lower permian košna conglomerates of the velebit mt. (croatia): modal composition, provenance and depositional environment 11 url4), but also in neoschwagerina beds of roadian age in slovenia (url5). the foraminifera turrispiroides cf. microsphaerica k.v. miklukho-maklay was not determined in the neighbouring regions, but was reported from the pennsylvanian to lower permian deposits of iran (yarahmadzah & vachard, 2019). limestones discovered at jajara hill near medak (today situated ca. 15 km ese from the košna voda spring), can help in determining the age of the ‘košna’ beds. these limestones overlie ~100 m thick shales and are overlain by ~300 m thick yellow ‘košna’ sandstones (kochansky-devidé, 1973), which represent the uppermost part of the ‘košna’ beds (raffaelli & šćavničar, 1968). the limestones comprise fusulinid taxa darvasites (alpites) ex gr. contractus (schellwien) and pseudofusulina cf. rakoveci ramovš & kochansky-devidé, together with diplosphaerina (previously: neotuberitina) maljavkini ( suleymanov, 1948). according to these fossil findings, kochansky-devidé (1973) suggested that the ‘košna’ beds are contemporaneous with the trogkofel limestones in slovenia (karavanke, ortnek) and the carnic alps, which have been assigned an artinskian/kungurian age (fig. 13; schaffshauser et al., 2015). 5.3. comparison with similar formations in the neighbouring regions the upper palaeozoic deposits of the eastern alps, southern alps and outer dinarides result from similar tectono-sedimentary evolution and can therefore be compared. the conglomerates were deposited as a result of variscan and saalian orogenic movements mostly in alluvial fan environments in eastern lombardy and the dolomites (krainer, 1989, 1993), whereas the conglomerates in the eastern and southern alps represent deposition in more distal settings, such as fluvial, lacustrine or deltaic environments (vozárová et al., 2009). the lateto post-variscan sequence is divided into two tectono-sedimentary cycles, separated by a major unconformity caused by the saalian orogenic movements (schönlaub, 1982; krainer, 1993; cassinis et al., 2012), known also as the “mid-permian tectonic episode” (deroin & bonin, 2003). sediments of the lower cycle were deposited in alluvial and lacustrine settings with several volcanoclastic intervals, within intramontane strike-slip and pull-apart basins (e.g., cassinis & perotti, 2007) from the late carboniferous to the permian (krainer, 1993; cassinis et al., 2013). despite the major stratigraphic gap, the middle?/upper permian to lower triassic sediments of the upper cycle conformably overlie the lower permian sequence of the lower cycle (krainer, 1993). the contact between the deposits of the two cycles is in places unexposed, erosional or undetermined. the beginning of the upper cycle is characterized by the deposition of val daone conglomerates in the lombardian alps, which comprise conglomerates, microconglomerates and sandstones with fragments of quartz and various magmatic rocks, plant debris and coal lenses (fig. 13; cassinis et al., 2008; gretter et al., 2013). the conglomerates are multicoloured (white, greyish, reddish, greenish), show clast imbrication and fining-upwards cycles, and are overlain by the laminated val gardena sandstone (grödner sandstein) (fig.13; cassinis et al., 2008; gretter et al., 2013). such transition is attributed to a shift from alluvial fan to fluvial environments (gretter et al., 2013). these conglomerates were deposited at the margins of sedimentary basins along a slope break in response to an extensional tectonic regime (cassinis et al., 1995, 2012; gretter et al., 2013). their age was first considered to be late permian (cassinis et al., 1995, 2012), but was later revised to the middle permian on the basis of palynological data (gretter et al., 2013). in general, the middle/late permian was characterised by clastic sedimentation, followed by carbonate and/or evaporite sedimentation (fig. 13). figure 13. upper palaeozoic deposits in the area of the southern and eastern alps, and velebit mt. (compiled and modified after kochansky-devidé (1973), ramovš et al. (1990), krainer (1993), marocchi et al. (2008) and cassinis et al. (2012)). g eo lo gi a c ro at ic a geologia croatica 77/112 in the western part of the southern alps (dolomites), the lower cycle is represented by the red and greenish-grey ponte gardena/waidbruck conglomerate, overlain by the acidic athesian volcanic group or district (fig. 13; visonà et al., 2007; marocchi et al., 2008), previously named the bolzano volcanic complex (e.g., krainer, 1989, 2005; vozárová et al., 2009). this conglomerate represents alluvial-fan sediments deposited under semi-arid climatic conditions (krainer, 1989) and is interbedded with volcanic rocks related to the beginning of the athesian volcanic activity during the middle artinskian (visonà et al., 2007). in the eastern part of the southern alps (the sexten dolomites), the lower permian sexten breccias and conglomerates occur as an equivalent of the ponte gardena conglomerate (fig. 13; flügel & kraus, 1986; krainer, 1993 and references therein). the middle-upper permian sediments of the upper cycle begin with the tarvis breccia at the base, which is followed by the grödner sandstein (val gardena sandstone) and the bellerophon formation (fig. 13; krainer, 1993; vozárová et al., 2009). the sexten breccias and conglomerates and the tarvis breccia are interpreted to represent deposition from debris flows and stream-channel flows in alluvial fan environments (flügel & kraus, 1986) and are considered as equivalents of the val daone conglomerates even though these basal bodies of the second permian cycle could not necessarily be assessed as quite synchronous (fig. 13; cassinis et al., 2008). in the carnic alps and the karavanke mountains, shallow marine clastic and carbonate depositional environments prevailed through most of the permian (krainer, 2005; shaffauser et al., 2015). the lower permian lower tectono-sedimentary cycle in this area is represented by the rattendorf and trogkofel groups consisting primarily of limestones (fig. 13; krainer, 1993). in the southern karavanke mountains, the trogkofel group is represented mostly by clastic deposits intercalated with thin beds of conodont-rich dark limestones (ramovš, 1963, 1968; kochansky-devidé, 1973). this clastic sequence also includes olistoliths composed of trogkofel limestone and is considered to represent a deep-marine depositional environment (kochansky-devidé, 1973; krainer, 1993). the midpermian hiatus separates the trogkofel group from the overlying upper cycle which includes the non-marine tarvis breccia, the gröden formation and the bellerophon formation (fig. 13; krainer, 1993). the tarvis breccia consists mostly of trogkofel limestone fragments and subordinate fragments of quartz, magmatic rocks, sandstones, chert and phyllite surrounded by a red to grey clayey matrix (krainer, 1993). this breccia is interpreted as a scarpfoot fan deposit and proximal debris flow, possibly deposited in an arid environment or coastal sabkha based on the occurrence of calcareous concretions (flügel & kraus, 1986; krainer, 1993). the sedimentary features and occurrence of large trogkofel limestone clasts in the tarvis breccia renders it rather similar to the ‘košna’ conglomerates. clastic deposition in the vicinity of ortnek in slovenia is attributed to the early to middle permian, with the lower part consisting of grey to occasionally red quartz conglomerates and quartz sandstones deposited in a shallow marine environment (ramovš & kochansky-devidé, 1965; ramovš, 1968). plant remains and coal intercalations in these deposits suggest their depositional proximity to a vegetated hinterland (ramovš, 1968). the upper part of the upper palaeozoic succession in slovenia comprises grey shales alternating with organic-rich quartz sandstones (ramovš, 1968). limestone lenses, limestone breccias and breccia-conglomerates occur within the shales and are interpreted as small reefs and associated talus produced by reef erosion (ramovš & kochansky-devidé, 1965; ramovš, 1968). this palaeozoic succession corresponds to the clastic trogkofel beds (aljinović & sremac, 1997 and references therein). in the gorski kotar area of croatia, the palaeozoic complex of predominantly clastic deposits comprises carboniferous triticites sandstones overlain by permian sandstones, sandstone-shale intercalations, orthoquartzitic and petromictic conglomerates (salopek, 1949a, b, 1960; raffaelli & šćavničar, 1968; kochansky-devidé, 1973; aljinović, 1997; aljinović & sremac, 1997; vozárová et al., 2009). these permian clastic rocks have an uncertain stratigraphic position in different areas of gorski kotar, and have been the subject of many debates (see references in aljinović & sremac, 1997; aljinović et al., 2003). where present, fossiliferous limestone intercalations suggest an early to middle permian age. salopek (1960) described the aforementioned petromictic conglomerates with clasts of fossiliferous limestones as gröden-type deposits, attributing them a middle permian age. however, these findings have later been erroneously cited (see review by aljinović & sremac, 1997), which led to the misconception that upper permian gröden clastics exist in the area of gorski kotar. nonetheless, sandstone intercalations within this lower–middle permian clastic series are commonly rich in plant detritus, suggesting their depositional proximity to an uplifted hinterland (aljinović et al., 2003). despite the debate regarding the stratigraphic attribution, most researchers concur with the notion that this clastic series was most likely deposited in a shallow marine environment, most likely fan deltas that developed in response to early to middle permian tectonic activity (grubić, 1980; aljinović, 1997; aljinović & sremac, 1997; aljinović et al., 2003). based on the described tectono-stratigraphic development within the adria-dinaria megaterrane, it is evident that the ‘košna’ conglomerates are comparable with similar lithological units in the neighbouring regions and may be considered as lateral equivalents of the val daone conglomerates and the tarvis breccia in the alps. their sedimentological features suggest deposition from coarse-grained tractive flows and occasional debris flows, most likely on mouth bars or the subaqueous slopes of a fan delta or river delta (nemec & steel, 1984). 6. conclusions 1. the ‘košna’ conglomerates from the brušane area of the velebit mt., croatia are of lower permian, most probably artinskian age, polymict, clast-supported and matrix supported conglomerates, in places breccia-conglomerates with dominantly red coarse-grained matrix, coloured by hae matite. 2. the sediment forming the ‘košna’ conglomerates most likely originates from weathering of the variscan mountains in (semi)-arid and partly humid climatic conditions. 3. it is suggested that the material from the variscan mountains was reworked and transported by alluvial systems into marine settings where it was deposited most likely on the subaqueous slopes of a fan-delta or river delta. 4. determined microfossils from the limestone clasts of the ‘košna’ conglomerates are of late carboniferous/early permian age. the identified fauna resemble the biota of the auernig and rattendorf groups. 5. the ‘košna’ conglomerates show structural and textural similarities with permian conglomerates from the eastern and southern alps. their deposition results from variscan g eologia c roatica palatinuš et al.: lower permian košna conglomerates of the velebit mt. (croatia): modal composition, provenance and depositional environment 13 and saalian orogenic movements that occurred in different areas at different times. considering the similar tectono-sedimentary development of the present-day southern alps and the dinarides during the palaeozoic, the ‘košna’ conglomerates can be considered as a lateral equivalent of the val daone conglomerates and/or the tarvis breccia. acknowledgement this study was supported by the croatian science foundation project ip-2019-04-7042, and the university of zagreb, financial support 107-f20-00005. thin-sections were prepared by željko ištuk and dejan vončina at the faculty of science, university of zagreb. robert košćal from the faculty of science, university of zagreb, helped in the preparation of the figures. formal reviews by ausonio ronchi and an anonymous reviewer are much appreciated for helping improve the manuscript. references aljinović, d. (1997): facijesi klastičnih sedimenata mlađega paleozoika i starijega trijasa gorskoga kotara [late palaeozoic and early scythian clastic facies – in croatian].– unpublished phd thesis, university of zagreb, 163 p. aljinović, d. & sremac, j. (1997): the middle and upper permian deposits in gorski kotar: facts and misconceptions.– geologia croatica, 50/2, 231–242. aljinović, d., sremac, j. & ibrahimpašić, h. (2003): permian and lower triassic facies of velebit mt. and the gorski kotar region (nw part of external dinarides).– in: vlahović, i. & tišljar, j. (eds.): field trip guidebook, 22nd ias meeting of sedimentology – opatija 2003, institute of geology – zagreb, 183–206. cassinis, g., toutin-morin, n. & virgili, c. (1995): a general outline of the permian continental basins in southwestern europe.– in: scholle, p.a., peryt, t.m. & ulmer-scholle, d.s. (eds.): the permian of northern pangea, volume 2: sedimentary basins and economic resources, springer, berlin, 137–157. doi: 10.1007/978-3-642-78590-0_8 cassinis, g. & perotti, c.r. (2007): a stratigraphic and tectonic review of the italian southern alpine permian.– palaeoworld, 16/1–3, 140–172. doi: 10.1016/j.palwor.2007.05.004 cassinis, g., ronchi, a., gretter, n. & durand, m. (2008): the val daone conglomerate: a middle permian key unit from the central southern alps (western trentino, italy), and regional stratigraphic imlications.– bollettino della società geologica italiana (italian journal of geosciences), 127/3, 519–532. cassinis, g., perotti, c.r. & ronchi, a. (2012): permian continental basins in the southern alps (italy) and peri-mediterranean correlations.– international journal of earth sciences, 101, 129–157. doi: 10.1007/s00531-011-0642-6 cassinis, g., perotti, c.r. & ronchi, a. (2013): geological remarks on the carboniferous-permian continental succession of southwestern europe.– new mexico museum of natural history and science bulletin, 60, 57–63. chetty, t.r.k. (2017): proterozoic orogens of india. chapter 1 – orogens, elsevier, 1–34. doi: 10.1016/b978-0-12-804441-4.00001-8 cleal, c.j., tenchov, y.g., sremac, j., đerek, t. & japundžić, s. (2015): pennsylvanian fossil flora from the velebit mountains and lika region (sw croatia).– bulletin of geosciences, 90/3, 721–742. doi: 10.3140/bull.geosci.1529 coney, p.j., jones, d.l. & monger, j.w.h. (1980): cordilleran suspect terranes.– nature, 288, 329–333. doi: 10.1038/288329a0 deroin, j.p. & bonin, b. (2003): late variscan tectonomagmatic activity in western europe and surrounding areas: the mid-permian episode.– boll. soc. geol. it. (volume speciale), 2, 169–184. dickinson, w.r., beard, l.s., brakenridge, g.r. & erjavec, j. (1983): provenance of north american phanerozoic sandstones in relation to tectonic setting.– geological society of america bulletin, 94, 222–235. doi: 10.1130/0016-7606(1983)94%3c222:ponaps%3e2.0.co;2 dickson, j.a.d. (1966): carbonate identification and genesis as revealed by staining.– journal of sedimentary petrology, 36/2, 491–505. drake, t.g. (1990): structural features in granular flows.– journal of geophysical research: solid earth, 95/b6, 8681–8696. doi: 10.1029/jb095ib06p08681 dunham, r.j. (1962): classification of carbonate rocks according to depositional texture.– in: ham, w.e. (ed.): classification of carbonate rocks, aapg, tulsa, 08–121. esteban, m. (1972): una nueva forma de microcodium elegans glueck 1912 y su relación con el caliche del eoceno inferior, marmella, provincial de tarragona (españa).– instituto de investigaciones geologicas, universidad de barcelona, revista, 27, 65–81. evamy, b.d. (1969): the precipitational environment and correlation of some calcite cements deducted from artificial staining.– journal of sedimentary petrology, 39/2, 787–821. flügel, e. & kraus, s. (1986): the lower permian sexten breccia (sexten dolomites) and the tarvis breccia (carnic alps): microfacies, depositional environment and paleotectonic implications.– memorie della società geologica italiana, 34, 67–90. foetterle, f. (1855): bericht über den geologischen untersuchungen im kroatischen küstenlande.– jahr. geol. r. a., 6, 417 p. folk, r.l. (1959): practical petrographic classification of limestones.– aapg bulletin, 43, 1–38. galloway, j.j. & harlton, b.h. (1928): some pennsylvanian foraminifera of oklahoma with special reference to the genus orobias.– journal of paleontology, 2, 338–357. gretter, n., ronchi, a., langone, a. & perotti, c.r. (2013): the transition between two major permian tectono-stratigraphic cycles in the central southern alps: results from facies analysis and u/pb geochronology.– international journal of earth sciences, 102, 1181–1202. doi: 10.1007/s00531-013-0886-4 grubić, a. (1980): early middle permian break in the geotectonic evolution of yugoslav dinarides.– in: metalogenesis of uranium, 26th inter. geol. cong., paris, sect. 13.2.2., geoinstitut, beograd, 203–214. hauer, f. (1868): geologische übersichtskarte der österreichisch-ungarische monarchie. blatt x, dalmatien.– jarh. geol. r. a., 18, 431–454. icdd (2004): powder diffraction file pdf-2, release 2004, newton square. kabanov, p., anadón, p. & krumbein, w.e. (2008): microcodium: an extensive review and a proposed non-rhizogenic biologically induces origin for its formation.– sedimentary geology, 205, 79–99. doi: 10.1016/j.sedgeo.2008.02.003 karamata, s. (2006): the geological development of the balkan peninsula related to the approach, collision and compression of gondwanan and eurasian units.– in: robertson, a.h.f. & mountrakis, d. (eds.): tectonic development of the eastern mediterranean region. geological society of london special publications, 260, 155–178. doi: 10.1144/gsl.sp.2006.260.01.07 koch, f. (1909a): geologijska prijegledna karta kraljevine hrvatske i slavonije. medaksv. rok, 1:75 000.– izdanje kraljevske hrvatsko-slavonsko-dalmatinske zemaljske vlade odjela za unutarnje poslove, zagreb. koch, f. (1909b): geologijska prijegledna karta kraljevine hrvatske i slavonije. tumač geologijske karte medak-sv. rok, 1:75 000.– naklada kraljevske zemaljske vlade odjela za unutarnje poslove, izdanje. geol. povj. 7, 1–31, zagreb. koch, f. (1914): izvještaj o geološkom snimanju velebita i like u godini 1913.– vijesti geološkog povjerenstva, 3–4, 27–29. koch, f. (1929a): geološka karta hrvatske, slavonije i dalmacije (prilog geološkoj karti kraljevine srba, hrvata i slovenaca). karlobag-jablanac.– naklada geol. zav. u zagrebu, repr. vojnogeogr. inst., beograd. koch, f. (1929b): tumač geološkoj karti karlobag-jablanac. prilog geologiji velebita i like.– posebno izdanje geol. zav. u zagrebu, 1–42. kochansky-devidé, v. (1955): karbonske i permske fuzulinidne foraminifere velebita i like. i. opći dio i karbon.– rad jazu, 305, 5–62. kochansky-devidé, v. (1959): karbonske i permske fuzulinidne foraminifere velebita i like. donji perm.– paleontologia jugoslavica, jazu, 3, 62 p. kochansky-devidé, v. (1965): karbonske i permske fuzulinidne foraminifere velebita i like. srednji i gornji perm.– acta geologica, jazu, 5, 101–150. kochansky-devidé, v. (1973): trogkofelske naslage u hrvatskoj.– geološki vjesnik, 26, 41–51. košir, a. (2004): microcodium revisited: root calcification products of terrestrial plants on carbonate-rich substrates.– journal of sedimentary research, 74/6, 845– 857. doi: 10.1306/040404740845 krainer, k. (1989): composition and evolution of lower periman molasse sediments (ponte gardena conglomerate) at the base of the bolzano volcanic complex, southern alps (n italy).– neues jahrbuch für geologie und paläontologie-monatshefte, 400–424. krainer, k. (1990): fazielle und sedimentpetrographische untesuchungen im perm des drauzuges.– mitteilunger der österreichischen geologischen gesellschaft, 82 (1989), 49–78. krainer, k. (1993): lateand post-varsician sediments of the eastern and southern alps.– in: von raumer, j.f. & neubauer, f. (ed.): premesozoic geology in the alps, springer-verlag, berlin-heidelberg, 537–564. krainer, k. (2005): the nonmarine permian of the eastern and southern alps: a review.– in: lucas, s.g. & zeigler, k.e. (ed.): the nonmarine permian. new mexico museum of history and science bulletin, 30, 159–169. marocchi, m., morelli, c., mair, v., klötzli, u. & bargossi, g.m. (2008): evolution of large silicic magma systems: new u–pb zircon data on the nw permian athesian volcanic group (southern alps, italy).– the journal of geology, 116/5, 480–498. doi: 10.1086/590135 miklukho-maklay, k.v. (1968): new kazanian cornuspiridae and nodosariidae from the russian platform. new species of fossil plants and invertebrates from the ussr.– vsegei, 2/1, 137–146. https://doi.org/10.1016/b978-0-12-804441-4.00001-8 g eo lo gi a c ro at ic a geologia croatica 77/114 milanović, m. (1982): carboniferous microfossil associations from gorski kotar, hrvatsko zagorje and banija.− palaeont. jugosl., 28, 1−34. mulder, t. & alexander, j. (2001): the physical character of subaqueous sedimentary density flows and their deposits.– sedimentology, 48, 269–299. doi: 10.1046/j.1365-3091.2001.00360.x nemec, w. & steel, r.j. (1984): alluvial and coastal conglomerates: their significant features and some comments on gravelly mass-flow deposits.– in: koster, e.h. & steel, r.j. (eds.): sedimentology of gravels and conglomerates. canadian society of petroleum geologists, memoir 10, 1–31. pettijohn, f.j., potter, p.e. & siever, r. (1987): sand and sandstone. 2nd edition, springer-verlag, new york, 553 p. raffaelli, p. & šćavničar, b. (1968): naslage gornjeg paleozoika like i gorskog kotara.– prvi kolokvij o geologiji dinaridov, geološki zavod in slovensko geološko društvo, 1, 21–27. ramovš, a. (1963): biostratigrahie der trogkofel-stufe in jugoslawien. neues. jahrb. geol. paläontol. monatsh, 1963/7, 382–388. ramovš, a. (1968): razvoj paleozoika v slovenskenm delu zunanjih dinaridov.– i kol. geol. dinaridov, 1. 7–19, ljubljana. ramovš, a., hinterlechner-ravnik, a., kalenić, m., karamata, s., kochansky-devidé, v., krstić, b., kulenović, e., mirković, m., petkovsky, p., sremac, j. & temkova, v. (1990): stratigraphic correlation forms of the yugoslav paleozoic.– rendiconti societa geologica italiana, 12 (1989), 359–383. ramovš, a. & kochansky-devidé, v. (1965): razvoj mlajšega paleozoika v okolici orlneka na dolenjskem.– razprave iv razreda sazu, 8, 319–416, ljubljana. reijmer, j.j.g., palmieri, p., groen, r. & floquet, m. (2015): calciturbidites and calcidebrites: sea-level variations or tectonic processes?– sedimentary geology, 317, 53–70. doi: 10.1016/j.sedgeo.2014.10.013 salopek, m. (1937): proučavanje gornjeg paleozoika u velebitu.– ljetopis jazu, 49, 188–192. salopek, m. (1938): proučavanje gornjeg paleozoika u brušansko-oštarijskom prodoru.– ljetopis jazu, 50, 127–132. salopek, m. (1939): karbon i perm u okolini brušana i sv. roka.– ljetopis jazu, 51, 135–139. salopek, m. (1940): gornji paleozoik i donji trijas u okolini sv. roka, raduča i metka.– ljetopis jazu, 52, 157–161. salopek, m. (1941): paleozojski prodor velike paklenice u velebitu.– ljetopis jazu, 53, 158–163. salopek, m. (1942): o gornjem paleozoiku velebita u okolini brušana i baških oštarija.– rad jazu, 274, 218–272. salopek, m. (1948): o gornjem paleozoiku sjeveroistočnog podnožja velebita i like.– prirodoslovna istraživanja jazu, 24, 1–75. salopek, m. (1949a): gornji paleozoik u okolini mrzle vodice u gorskom kotaru.– ljetopis jazu, 55 (1946–1948), 175–184. salopek, m. (1949b): o gornjem paleozoiku u okolini gerova i tršća u gorskom kotaru.– ljetopis jazu, 55 (1946–1948), 193–198. salopek, m. (1952): o gornjem permu velike paklenice u velebitu.– rad jazu, 289, 5–26. salopek, m. (1960): o gornjem paleozoiku u okolici mrzle vodice i crnoga luga.– acta geol., 2, 121–132. schaffhauser, m., krainer, k. & sanders, d. (2015): early permian carbonate shelf margin deposits: the type section of the trogkofel formation (artinskian/ kungurian), carnic alps, austria/italy. austrian journal of earth sciences, 108, 277–301. doi: 10.17738/ajes.2015.0026 schönlaub, h.p. (1982): die grauwackenzone in den eisenerzer alpen (österreich).– jb. geol. b.–a. 124, 361–423. schubert, r.i. (1908): zur geologie des österreichischen velebit.– jahrb. geol. r. a., 58, 345 p. schubert, r.i. (1910): erläuterunger zur geologischen karte der im reichsrate vertretenen königreiche und länder der österreich-ungarn monarchie, sw-grupper nr. 116, medak–sv rok.– geol. reichsanst. wien, 1–32. sokač, b., nikler, l., velić, i. & mamužić, p. (1974): osnovna geološka karta sfrj 1:100 000. list gospić l33-127 [basic geological map of sfry 1:100000, gospić sheet l33-127 – in croatian].– institut za geološka istraživanja zagreb (1967), savezni geološki institut, beograd. sokač, b., šćavničar, b. & velić, i. (1976): osnovna geološka karta sfrj 1:100.000, tumač za list gospić l33–127 [basic geological map of sfry 1:100000, geology of the gospić sheet – in croatian].– institut za geološka istraživanja, zagreb (1967), savezni geološki institut beograd, 64 p. sremac, j. (1991): zone neoschwagerina craticulifera in the middle velebit mt. (croatia, yugoslavia).– geologija, 34, 7–55. sremac, j. (2005): equatorial shelf of the palaeozoic supercontinent – cradle of the adriatic carbonate platform.– geologia croatica, 58/1, 1–19. doi: 10.4154/ gc.2005.01 sremac, j. (2007): the palaeozoic of velebit mt.– in: grgasović, t. & vlahović, i. (eds.): field trip guidebook and abstracts, 9th international symposium on fossil algae croatia in zagreb, 2007. croatian geological survey, 13–19. sremac, j. (2012): influence on terrestrial sedimentation in pennsylvanian rocks of croatia.– geologia croatica, 65/3, 273–282. doi: 10.4154/gc.2012.18 sremac, j. & kochansky-devidé, v. (1982): paleozoik hrvatske (kratki pregled).– in: sremac, j. (eds.): vodič ekskurzije. terenski sastanak velebit (1982). igcp project br. 5, jugoslavenska radna grupa, 3–7 (41–42), zagreb. sudar, v., aljinović, d., smirčić, d. & barudžija, u. (2016): composition and provenance of gröden sandstone from the velebit mts.– the mining-geologypetroleum engineering bulletin, 31/1, 53–67. doi: 10.17794/rgn.2016.1.6 suleymanov, i.s. (1948): about some lower carboniferous foraminifera from sterlitamak district.– akademiya nauk sssr, trudy instituta geologicheskikh nauk, geologicheskaya seriya, 62/19, 244–245. swanson, r.g. (1981): standard abbreviations for lithologic descriptions.– in: sample examination manual, american association of petroleum geologists, tulsa, oklahoma, 140 p. terry, r.d. & chilingar, g.v. (1955): summary of „concerning some additional aids in studying sedimentary formations“by m.s. shvetsov.– journal of sedimentary petrology, 25/3, 229–234. tišljar, j. (1994): sedimentne stijene.– školska knjiga, zagreb, 433 p. tišljar, j., vlahović, i., sremac, j., velić, i., veseli, v. & stanković, d. (1991): excursion a – velebit mt. permian-jurassic.– in: velić, i. & vlahović, i. (eds.): some aspects of the shallow water sedimentation of the adriatic carbonate platform (permain do eocene). the second international symposium of the adriatic carbonate platform, zadar, may 1991, excursion guidebook, 1–50, zagreb. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeography, palaeoclimatology, palaeoecology, 220, 333–360. doi: 10.1016/j.palaeo.2005.01.011 vozárová, a., ebner, f, kovacs, s., krautner, h.-g., szedekenyi, t., krstić, b., sremac, j., aljinović, d., novak, m. & skaberne, d. (2009): late variscian (carboniferous to permian) environments in the circum pannonian region.– geologica carpathica, 60/1, 71–104. vrkljan, m., borojević šoštarić, s. & tomašić, n. (2018): optička mineralogija, određivanje minerala polarizacijskim mikroskopom.– rgnf, pmf, zagreb, 331 p. weltje, g.j. (1994): provenance and dispersal of sand-sized sediments: reconstruction of dispersal patterns and sources of sand-sized sediments by means of inverse modeling techniques. phd thesis, university of utrecht. geologica ultraectina, 121 p. weltje, g.j., meijer, x.d. & de boer, p.l. (1998): stratigraphic inversion of siliciclastic basin fills: a note on the distinction between supply resulting from tectonic and climatic forcing.– basin research, 10, 129–153. doi: 10.1046/j.1365 2117.1998.00057.x werner, t., lewandowski, m., vlahović, i., velić, i. & sidorczuk, m. (2015): paleomagnetism and rock magnetism of the permian redbeds from the velebit mt. (karst dinarides, croatia): dating of the early alpine tectonics in the western dinarides by a secondary magnetization.– tectonophysics, 651–652, 199–215. whitney, d.l. & evans, b.w. (2010): abbreviations for names of rock-forming minerals.– american mineralogist, 95, 185–187. doi: 10.2138/am.2010.3371 yarahmadzahi, h. & vachard, d. (2019): moscovian-asselian (middle pennsylvanian–earliest cisuralian) smaller foraminifers from the asad-abad section (sanandaj–sirjan zone, central iran).– journal of foraminiferal research, 49/2, 107–130. doi: 10.2113/gsjfr.49.2.107 url1: https://www.gbif.org/occurrence/1698325387 (visited september 2022) url2: https://paleobiodb.org/classic/basiccollectionsearch?collection_no=36241&is_ real_user=1 (visited september 2022) url3: https://www.mindat.org/paleo_loc.php?id=83955 (visited september 2022) url4: https://www.gbif.org/occurrence/1698445150 (visited september 2022) url5: https://www.gbif.org/occurrence/1698325462 (visited november 2023) https://www.gbif.org/occurrence/1698325387 https://paleobiodb.org/classic/basiccollectionsearch?collection_no=36241&is_real_user=1 https://paleobiodb.org/classic/basiccollectionsearch?collection_no=36241&is_real_user=1 https://www.mindat.org/paleo_loc.php?id=83955 https://www.gbif.org/occurrence/1698445150 https://www.gbif.org/occurrence/1698325462 www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2025 | 78/1 | 15–29 | 10 figs. | 2 tabs. | 1. introduction the studied sharib-1x borehole (lat. 30° 11' 36'' n and long. 28° 19' 06'' e) is located east of the qattara depression in the northern western desert (fig. 1), as a part of the unstable shelf of egypt. the borehole lies at the ras qattara ridge (sharibsheiba high), which marks the southern boundary of the abu gharadig basin. here, productive oil and gas fields were dis­ covered (see saad et al., 2023). the borehole was palynologically investigated by omran et al. (1990), in which the original stratigraphy (wepco, 1971, taken from the strati graphic log), was revised based on dinoflagellate cysts, recorded from five samples (depths 2124, 2023, 1950, 1868, 1858 m, respectively). other contributions such as schrank & ibrahim, 1995; mahmoud & deaf, 2007; tahoun & ied, 2019; deaf et al., 2020; mansour et al., 2021; mahmoud et al., 2023) constrained this interval to the middle-upper albian. zobaa et al. (2013) investigated an interval from the same borehole (depths from 1874 to 1633 m) and dated a carbonate interval (depths from 1874 to 1837 m) as middle to late jurassic (masajid fm) in age, based on dinoflagellate cysts. their spore and pollen association lacks the angiosperms and the elaterates. here, we investigated deeper downhole sediments, at depths from 2078 m to 1850 m. in light of the recently published spores and pollen information in albian biostratigraphy and palaeoecology of the sharib-1x borehole (northern egypt): insights from palynomorphs and palynofacies miran mostafa khalaf1,* and magdy salah mahmoud2 1 sohag university, faculty of science, geology department, 82524 sohag, egypt; (*corresponding author: miran_kha2@science.sohag.edu.eg) 2 assiut university, faculty of science, geology department, 71516 assiut, egypt; (magdysm@aun.edu.eg) doi: 10.4154/gc.2025.02 abstract well-preserved terrestrial palynoflora assemblages, dominated by pteridophyte spores (e.g., deltoidospora, triplanosporites, and dictyophyllidites), with angiosperms and elaterate-bearing taxa, were recorded from the kharita formation, northern egypt. biostratigraphically, the angiosperm pollen afropollis jardinus is the most significant element, along with elaterates including elaterosporites klaszii and elaterocolpites castelainii, in dating the kharita formation and confirming its previous (dinoflagellate) albian dating. we applied current and previous documented redox states in the borehole and discovered evidence of missing of angiosperms and elaterates from some stratigraphic levels. at stratigraphic horizons where opaque phytoclasts are extraordinarily abundant, oxidation is highly expected and, consequently, some palynomorphs of the original palynological assemblages may have been oxidized. at other horizons with mild oxidation, some palynomorphs cannot be preserved due to environmental restrictions. under these circumstances, if these marker taxa are missing, age assessments can be unreliable. therefore, care must be taken in order to determine reliable palynostratigraphy. an oxic to dysoxic-suboxic marginal marine environment was inferred, with a few examples of periodic distal settings at the basal and top parts of the kharita formation. the kharita palynofloras, as part of the palynofloristic albian-cenomanian african-south american (asa) province, reflect the influence of the break-up of the continents of africa and south america. they reflect the resultant global palaeoclimate change near the equator, which brought humid conditions to egypt during albian times. egypt, see the comprehensive literature listing in soliman & el atfy (2023), we documented an unequivocal terrestrial albian association with angiosperms and elaterates. these data offered a unique opportunity to revise the age assessments of the borehole. omran et al. (1990) suggested a proximal (restricted) to inner-shelf environment for the kharita formation (albian) in the sharib-1x borehole. they noted that the sea gradually shallowed to the south, to reach the area of the borehole during the albian. oxidation of the palynological organic matter is known to occur during transport (e.g., tyson, 1995; batten, 1996). the impact of such oxidation on the selective preservation of terrestrial palynomorphs can only be depicted by looking at the total palynofacies. for instance, if the palynofacies is domi nated by opaques, this would mean that, at least, part of the recorded palynomorphs may have oxidized. the impact of oxidation can be clearly seen from the occurrence of, for ins tance, lath-shaped opaque phytoclasts. in this case, the amor phous organic matter (aom), together with sensitive palyno morphs, would oxidize more readily than the phytoclasts and, consequently, disappear from the palynological content. labora tory oxidation techniques, avoided herein (e.g., acetolysis; nitric acid treatment), are also known to cause physical degradation to spores and pollen associations (e.g., jardiné article history: manuscript received: january 30, 2024 revised manuscript accepted: october 08, 2024 available online: february 26, 2025 keywords: palynomorphs, kharita formation, albian, marginal environment, egypt g eo lo gi a c ro at ic a 16 geologia croatica 78/1 et al., 2015). however, schrank (1988) stated "after oxida­ tion with cold hno3 and subsequent alkali (koh or nh4oh) treatment, an expansion of the periphragm was observed". he also noted that after excessive oxidation most dinoflagellates are eliminated. even so, the impact of degradation on selective sporomorph species by excess oxygen in depositional basins is not, to our knowledge, described as being the same as for dinoflagellates. for dinoflagellates, in cases of excess o2, sen si tive (heterotrophic) species are more susceptible to post-depo sitional degradation than autotrophic ones (e.g., zonneveld et al., 2007). we are interested in investigating the palynomorph composition of the kharita formation, sharib-1x borehole, for biostratigraphic and palaeoenvironmental implications. we intend to apply land­derived palynomorphs to offer an additio­ nal palynological age assessment of the albian interval of the well, which was previously dated on the basis of dinoflagellate cysts (omran et al., 1990). we are also interested in providing insights into understanding terrestrial palynomorph degradation and its impact on reliable paly nological age assessment. we also aim to study the palynofacies constituents of the investigated albian interval of the borehole and their importance in understanding the palaeoenvironment and its redox states. among our objectives is the correlation of the albian miospores association with other contemporaneous counterparts from additional geographically-related vegetation provinces in the african and south american continents. we also compare these miospores with other areas worldwide. 2. geological setting the northern western desert has a spectacular subsurface geology. this northern segment of the african platform is made up of thick sedimentary, cambrian to holocene, layers that gradually slope seaward. most of this area is blanketed by miocene deposits, whereas along the mediterranean coast, limi ted pliocene shales and sandstones are exposed. many petroliferous rift basins, developed during the mesozoic fragmen tation of gondwana and the opening of the southern neotethys, formed in northern egypt (e.g., tassy et al., 2015). these basins are often aligned in half-grabens-oriented e-w, ne­sw and ene­wsw directions (guiraud et al., 2005). structurally, the northern western desert belongs to the “unstable shelf” of said (1962), which was tectonically active during most of the phanerozoic; subsidence, uplift and basin inversion occurred (hantar, 1990; el atfy, 2021). the thickest of the phanerozoic layers occur in the abu gharadig basin (8-9 km thick), while it may only reach as little as 3 to 6 km elsewhere (hantar, 1990). the western desert in general is defined by a northwestward thickening palaeozoic sequence and a northward thickening prism of mesozoic and palaeogene strata. the east-west trending sharib-sheiba high forms a regional uplift that divides the southern and coastal northern western desert basins, whereas the examined borehole is located at the northern boundary of this trend, indicating that sediments were deposited in shallower settings (e.g.p.c., 1992). a generalized stratigraphic column of the cretaceous rock units in the western desert modified after bosworth & tari (2021) is presented in figure 2. in the shushan basin, to the north of the investigated borehole, the palynological dating showed that lower cretaceous (hauterivian to albian) sediments overlie the jurassic strata (see mahmoud et al., 2023). southward, where the sharib­1x borehole lies, the hauterivian to aptian sediments gradually disappear (omran et al., 1990). the regionally widespread figure 1. geographical map of egypt showing the location of the investigated sharib-1x borehole. g eologia c roatica 17khalaf and mahmoud: albian biostratigraphy and palaeoecology of the sharib-1x borehole (northern egypt): insights from palynomorphs ... aptian carbonate units, in the northern western desert, known as the alamein formation, in addition to the dahab formation, are missing at the sharib-sheiba high, where the sharib-1x borehole is located (omran et al., 1990). therefore, the albian kharita formation directly overlies the middle jurassic (?bajocian–callovian) sediments (omran et al., 1990). this pronounced and significant hiatus means that the alamein carbonates were not deposited in the study area due to uplifting that was initiated during the middle jurassic (bayoumi & lotfy, 1989; meshref, 1996). this gap seems to have highly impacted the chronostratigraphy of the lower cretaceous sharib-1x borehole, as seen from previous controversial age assessments (wepco, 1971; omran et al., 1990; zobaa et al., 2013). 3. lithostratigraphy the studied kharita formation consists mainly of sandstones with fining upward sequences. shale and thin limestone streaks are sporadically interbedded with sandstones. thicker sandstone with shale intercalations occurs in the lower part of this unit. it unconformably overlies the alamein formation (ghorab et al., 1971; said, 1990; e.g.p.c., 1992). the sand stones, siltstones and limestones of the overlying bahariya formation (norton, 1967) cover large areas in the sub surface of the western desert and rest, sometimes unconformably, on the kharita formation. the type section of the kharita formation is placed between 2890 and 2501 m in the kharita­1 borehole. the maximum thickness of this unit was reported from the northernmost deeper basins (matruh-1 borehole, 1100 m). the upper part of the kharita formation is made up of clean coastal plain sandstone with shale and silt interbeds (schlumberger, 1984), whilst the basal level is made up of finely laminated shallow marine sandstone, siltstone, and shale intercalations. in the sharib-1x borehole, this rock unit is characterized at the base by coarse-grained mildly calcareous sandstone of varied colours, which are interbedded upwards with greenish to dark grey fissile calcareous shale. according to palynological evidence, the kharita formation dates from the early to middle albian (aboul ela & tahoun, 2010; tahoun, 2012; tahoun et al., 2012, 2015; gentzis et al., 2018; tahoun et al., 2018; gentzis et al., 2019). the formation was interpreted to reflect a high­energy and regres­ sive shallow marine environment (e.g., omran et al., 1990; e.g.p.c., 1992; schrank & ibrahim, 1995; deaf et al., 2014; el atfy et al., 2019; gentzis et al., 2019; mahmoud et al., 2019). 4. material and methods eleven cuttings samples, collected from the kharita formation (albian) of the sharib-1x borehole (fig. 3) were palynologically figure 2. generalized stratigraphic column showing the main cretaceous rock units in the northern western desert of egypt (modified after bosworth & tari, 2021). g eo lo gi a c ro at ic a 18 geologia croatica 78/1 investigated in this study using cold acid maceration. they were collected at depths from 2078 to 1850 m. about 20 grams were digested according to traditional laboratory processing techniques (e.g., phipps & playford, 1984; traverse, 2007). samples were first treated with hydrochloric acid (hcl 32%) to remove carbonates (caco3) and then washed several times with distilled water until neutralized. this was followed by maceration in hydrofluoric acid hf (40%) to dissolve silicates and then washed again several times until neutralized. after the digestion was completed, residues were then sieved using a 15 μm nylon screen. ultrasonic vibration, acetolysis, nitric acid treatment as well as any other treatment by oxidizing agents were avoided to protect the organic matter from breaking down or decomposing. this residue was used in palynofacies analysis. part of the residue was treated by mild ultrasonic vibration for a few seconds to concentrate palynomorphs. three to five slides from each sample, prepared with glycerin jelly as a mounting medium, were examined under light microscopy. samples were examined using an axiolab transmitted white light microscope at various magnifications to conduct semi-quantitative studies of organic matter, with photomicrography using its digital camera. approximately 250 specimens of different palynomorphs were counted, with the calculation of the relative percentages of palynomorph groups (table 1). another set of 500 total paly nological organic matter (tpom) particulates was counted to express the relative abundances of the total recorded palynofacies components (table 2). the aom-phytoclastspalynomorphs (app) ternary plot of tyson (1995) is used primarily to infer the redox conditions. the ratio of marine to continental palynomorphs (m/c ratio) is also applied to assist in the discrimination between proximal and distal settings. it was calculated; using the count set of palynomorphs, by dividing the total number of counted marine palynomorphs by the total count of palynomorphs in every sample and then multiplying by 100. 5. results all samples were productive, giving low to moderate palyno morphs with low diversity and moderate abundance. the preservation of organic materials is often moderate. the marine: continental ratio (m/c ratio), the relative abundance of major palynomorph groups, and the relafigure 3. lithological column of the sharib-1x borehole, showing the positions of the studied samples, previous palynologically investigated intervals by zobaa et al. (2013) and the original stratigraphy (wepco, 1971). g eologia c roatica 19khalaf and mahmoud: albian biostratigraphy and palaeoecology of the sharib-1x borehole (northern egypt): insights from palynomorphs ... table 1. counts of the recorded palynom orphs in the investigated a lbian interval of the sharib-1x borehole. these data w ere used in the construction of the sem i-quantitative distribution of sporom orphs, in the graphic presentation of palynom orphs and palynom orph groups and in the synthesis of the sm p ternary diagram of d u rin g er & d o u bin g er (1985). age/stage formation sample no. depth ft (m) spores triplanosporites spp. deltoidospora hallii dictyophyllidites harrisii cicatricosisporites spp. deltoidospora australis deltoidospora spp. dictyophyllidites spp. concavissimisporites spp. deltoidospora toralis gemmatriletes sp. matonisporites sp. biretisporites potoniaei gleicheniidites senonicus gleicheniidites feronensis crybelosporites pannuceus auritulinasporites intrastriatus converrucosisporites sp. concavissimisporites variverrucatus cibotiumspora jurienensis murospora sp. densoisporites sp. microfoveolatisporites sp. gymnosperm pollen callialasporites trilobatus callialasporites turbatus cycadopites spp. inaperturopollenites undulatus arucariacites australis balmeiopsis limbatus classopollis classoides exesipollenites sp. monosulcites sp. bennettiteaepollenites regaliae bisaccate pollen classopollis sp. taxodiaceaepollenites sp. 1 elaterate pollen elaterocolpites castelainii elaterosporites klaszii elaterosporites acuminatus angiospem pollen afropollis jardinus retimonocolpites ghazalii retimonocolpites sp. monocolpopollenites sp. afropollis aff. jardinus monocolpites spp. total sporomorphs total marine palynomorphs total palynomorphs middle-upper albian kharita 11 6070 (1850) 15 10 8 10 13 10 7 10 9 8 5 5 25 24 54 10 2 225 17 242 10 6130 (1868) 15 12 10 15 9 10 11 9 9 4 5 4 7 15 10 10 10 1 4 170 80 250 9 6180 (1883) 20 11 10 31 10 14 12 9 8 1 7 15 19 8 7 7 2 2 193 55 248 8 6200 (1889) 20 11 10 8 # 9 9 8 12 5 5 12 10 10 20 10 10 1 10 10 3 3 4 10 235 15 250 7 6270 (1911) 26 13 15 27 11 9 7 12 11 15 20 9 11 12 10 4 13 225 25 250 6 6310 (1923) 23 12 9 13 29 11 15 13 10 10 11 14 9 1 11 9 4 13 7 4 229 6 235 5 6420 (1956) 28 17 22 31 15 16 1 27 11 4 25 11 11 10 2 2 2 4 239 11 250 4 6570 (2002) 18 14 10 13 28 16 13 13 17 15 11 15 23 12 10 10 7 245 5 250 3 6740 (2054) 23 16 6 30 13 19 18 15 20 35 12 12 3 10 11 243 5 248 2 6760 (2060) 17 9 17 8 9 12 13 10 6 13 23 13 40 5 1 1 5 202 41 243 1 6820 (2078) 12 9 11 8 8 10 9 12 9 24 15 1 1 4 10 143 105 248 barren of angiosperm pollen tive abundances of the main total palynological organic matter (tpom) components are presented graphically (fig. 4). in the majority of samples, the m/c ratio (fig. 4a) reflects values from 2:98 (sample 4, depth 2002 m) to a maximum of 16.9:83.1 (sample 2, depth 2060 m). at three horizons, marine dinocysts and/or foraminiferal linings reach percentages up to 73%, 28%, and 47% of total palynomorphs (samples 1, 9, and 10, depths 2078, 2493 and 1868 m) respectively. at these stratigraphic levels, the m/c ratio shows the highest values between 22.2:77.8 (sample 9, depth 1883 m) to 42.3:57.7 (sample 1, depth 2078 m). terrestrial pollen and spores are the dominant paly nomorphs across the whole investigated borehole inter val. they reach up to 98% of the total palynomorph content (sample 4, depth 2002 m). among the spores, the pteri do phyte ferns (fig. 4b) are the most abundant (up to 76.6%, depth 1923 m). the lowest relative percentage of these ferns was recorded in sample 1 (27% of total paly no morphs, depth 2078 m). they are mainly represented by the smooth (sub) triangular forms of the genera delto­ ido spora, triplanosporites, and dictyo phylli dites. orna mented (e.g., converrucosisporites) and other spores such as densoisporites are rare. gymnosperms (mainly calliala sporites, and classopollis) are common (up to 50.8% of total palynomorphs, sample 11, depth 1850 m). the bisaccate pollen and the elaterates are accessory components. they show spo radic lower relative percentages (up to 2.1% sample 2, depth 2060 m and 1.2% sample 3, depth 2054 m, of total palyno­ morphs). the angiosperms are represented by afropollis jardinus, afropollis aff. jardinus, retimo­ no colpites ghazalii, monocolpopollenites sp. and monocolpites spp. these angiosperms, together with the above mentioned elate rates, are the most significant from a biostratigraphic point of view. they comprise up to 8.5% of the total palynomorph content (sample 3, depth 2054 m). two samples lack angio sperms; the lowest relative percentage is 2% (sample 2, depth 2060 m). the predominant constituents of the tpom are brown wood whereas cuticles, membranous tissues, tracheids and resin are minor (fig. 4c). the brown phytoclasts and the opaques constitute the overwhelming majority of the palynofacies. they reach up to 74.2% of total palynofacies (sample 3, depth 2054 m). the brown phytoclasts and the opaques are usual ly equidimensional in outline, but lath-shaped parti cles were also observed. the aom is not as abundant as phytoclasts. at two levels, samples 1, depth 2078 m and 4 (depth 2002 m), it forms 22% and 36.8% of the total palyno facies, respectively. the palynomorph abundances do not show the same trend as the aom. samples 4 (depth 2002 m) and 10 (depth 1868 m) have the highest percentages of palyno morphs (33% and 35.8% of total palynofacies, respectively). a striking observation of g eo lo gi a c ro at ic a 20 geologia croatica 78/1 our palynofacies is the lower relative percentages of the opaque particulates (maximum abundance of 12% of total palynofacies, sample 2, depth 2060 m). the vertical stratigraphic distribution of the re cover ed spores and pollen grains, arranged by their highest occurrence (ho), is shown in figure 5a. details of the recovered dinoflagellate cysts, which were already pre­ viously recovered from the same investigated interval (mahmoud, 1989), are presented on figure 5b. 6. discussions 6.1. age assessment in africa, afropollis jardinus was discovered from foraminifera-dated albian samples of senegal and ivory coast (jardiné & magloire, 1965; as s. ci. 156 incertae sedis), gabon-congo-senegal (doyle et al., 1982) and egypt (schrank & ibrahim, 1995). this taxon was identified in colombia from an ammonite bed of late albian (to early cenomanian) age (herngreen & jimenez, 1990). in northern south america, this taxon has been recorded from foraminifera-dated sediments of early albian age in brazil (herngreen, 1973, 1975; regali et al., 1974; regali & viana, 1989) and peru (brenner, 1968). the elaterates are known to enter the palynological record in the ancient northern gondwana continent by the early albian. elatero­ sporites klaszii entered the stratigraphic records during the mid-albian to the mid-cenomanian in foraminifera-dated sediments from northern south america (müller, 1966; herngreen, 1973; herngreen & jimenez, 1990) and africa (jardiné & magloire, 1965; jardiné, 1967; schrank & ibrahim, 1995; tahoun et al., 2012; el beialy et al., 2010; zobaa & oboh­ikuenobe, 2018; deaf et al., 2014; el atfy et al., 2023). elaterocolpites castelainii, another elaterate, first appeared in the late albian (hochuli, 1981). although e. klaszii and e. castelainii also have their widest distribution in the late albian and early cenomanian of egypt and africa, they were considered to be restricted to the upper albian in the lower benue trough of nigeria (jardiné, 1967). usually, gymnosperms such as figure 4. a) marine to continental (m/c) ratio diagram; b) percentage frequencies of the main palynomorph groups; c) percentage frequencies of the main palynofacies categories. table 2. counts of the different palynofacies categories in the sharib-1x borehole. this data was used in the synthesis of the app ternary plot of tyson (1993). a ge /s ta ge fo rm at io n sa m pl e no . d ep th ft (m ) a m or ph ou s o rg an ic m at te r ( ao m ) ph yt oc la st s br ow n w oo d tr ac he id sa cu tic le s m em br an ou s t is su es re si n o pa qu es pp al yn om or ph s sp or es po lle n d in ofl ag el la te c ys ts m ic ro fo ra m in ife ra lin in gs to ta l p al yn of ac ie s m id dl eup pe r a lb ia n kh ar ita 11 6070 (1850) 25 341 2 2 1 0 20 57 42 10 0 500 10 6130 (1868) 27 235 5 9 5 0 40 55 39 25 60 500 9 6180 (1883) 24 300 5 7 5 0 35 66 41 17 0 500 8 6200 (1889) 30 235 10 12 6 2 35 75 70 25 0 500 7 6270 (1911) 25 260 5 5 8 0 55 76 57 9 0 500 6 6310 (1923) 15 274 3 3 9 0 60 83 49 3 1 500 5 6420 (1956) 30 293 3 15 10 0 53 65 29 1 1 500 4 6570 (2002) 184 130 3 3 5 0 10 95 68 2 0 500 3 6740 (2054) 10 351 12 5 2 1 45 40 32 2 0 500 2 6760 (2060) 15 280 5 5 10 0 60 57 51 17 0 500 1 6820 (2078) 110 228 13 2 7 7 20 42 36 20 15 500 g eologia c roatica 21khalaf and mahmoud: albian biostratigraphy and palaeoecology of the sharib-1x borehole (northern egypt): insights from palynomorphs ... araucariacites disappear in african basins during the cenomanian (jardiné & magloire, 1965). retimonocolpites ghazalii may be an important angiosperm pollen in the borehole; although the uppermost sample 11 has rare findings, its highest occurrence levels in the lower albian in the shushan basin (mahmoud et al., 2023) supports an albian date. the diverse dinoflagellate cyst association recovered by the second author (mahmoud, 1989), with no diagnostic jurassic dinocysts (fig. 5b), see next paragraph, confirms our creta­ ceous (albian) dating. the spores and gymnosperm associations, on the other hand, recovered here are long-ranging, although they are of cretaceous aspect. however, murospora is a significant aptian/albian spore in the regional palynofloras of egypt. crybelosporites pannuceus enters the palynological records during the aptian in sudan (kaska, 1989). it appeared later (albian) in africa (ne nigeria – lawal & moullade, 1986; ne libya – batten & uwins, 1985), in south america (peru – brenner, 1968) and in the middle east (qatar – el beialy & al­hitmi, 1994). younger albian–cenomanian records were also recorded in egypt (schrank & mahmoud, 1998). several palynological contributions from the western desert of egypt considered concavissimisporites punctatus to date the early-middle albian palynofloral assemblages (e.g., el shamma et al., 1999; tahoun et al., 2015; aboul ela et al., 2020) and to discriminate between the kharita and the overlying bahariya formations (aboul ela et al., 2020). in europe, this species defines the middle albian deposits in portugal figure 5. a) semi-quantitative distribution, by highest occurrence, of terrestrial spores and pollen, (calculated from total sporomorphs) in the investigated albian interval, sharib-1x borehole; b) dinocysts semi-quantitative distribution chart by highest occurrence, sharib-1x borehole (redrawn after mahmoud, 1989; taxonomic names revised according to fensome et al., 2019). a b g eo lo gi a c ro at ic a 22 geologia croatica 78/1 (hasenboehler, 1981). some grains within concavissimi­ sporites spp. in the uppermost samples (9 and 11) bear affinities with c. punctatus that can also support an albian date. omran et al. (1990) studied the interval 2124 to 1850 m and assigned it to the middle­late albian based on dinoflagellate cysts (dinopterygium cladoides, oodnadattia tuberculata and subtilisphaera cheit). they also addressed the absence of the cenomanian palynoflora and any other diagnostic sporomorphs, except for a few discoveries of the two genera clavatipollenites and elaterosporites to support their sugges tion. omran et al. (1990) did not provide any quantitative or qualitative data about the five samples studied from sharib-1x, except for the composite chart of the three wells they studied in their published paper. they only illustrated the main palynofloral group where there is a high percentage of marine palynomorphs. they assigned the studied interval to palynoflora d3 (albian/?early cenomanian), which is charac­ terized by the presence of achomosphaera, cassiculosphaeridia re ticu lata, cyclonephelium, dapsilidinium chems, dino­ pterygium cladoides, escharisphaeridia, florentinia mantellii, florentinia stallata, hystrichosphaeridium arborispinum and odontochitina costata. the palynoflora is dominated by cribro peridinium and systematophora. jurassic marker dinocysts are completely missing in the studied interval of the well, except in the lowermost sample, at a depth of 2124 m, where korystocysta kettonensis (now k. gochtii) and korystocysta norrisii (now k. pachyderma) have their first downhole occu­ rrence in this sample, with an unequivocal jurassic (?bajocian– callovian) age. as has been noted earlier in the "results" sec­ tion, details of these dinocysts, beside others, are presented for the investigated sharib-1x well. this semi-quantitative distribution is more robust than that of the terrestrial palynomorphs, especially the angiosperms and the elaterates, and reflects appreciable percentage frequencies of index cretaceous and other dinoflagellates. however, omran et al. (1990) did not provide any data about the lithostratigraphic unit they studied from sharib-1x (no formation name is mentioned) while wepco (1971) assigned the studied interval to the masajid formation (jurassic). the kharita formation is primarily a clastic unit, and there is no published data indicating such thick carbonate bodies or shale intercalations within the formation. however, on the basis of the current findings, the carbonate interval is not as thick as the masajid formation (jurassic) and correlates with the kharita formation (cretaceous), but the uppermost carbonates can be correlated with the basal medewar formation (lateral equivalent of the bahariya formation), as can be seen from a generalized stratigraphic column of the western desert (schlumberger, 1984, 1995; column presented in lotfy et al., 2020, fig. 2, p. 245). a few metres above these samples in the same sharib-1x borehole, few dinoflagellates of adnatosphaeridium caulleryi, ctenidodinium combazii, escharisphaeridia pocockii, sentusidinium rioultii and systematophora penicillata, were recorded from the carbonate interval by zobaa et al. (2013), and discussions therein, palynozone 1, depths from 1880 to 1818 m; dated as jurassic. for example, a. caulleryi has biostratigraphic records of berriasian–valanginian (millioud et al., 1975), berriasian– lower hauterivian (smelror et al., 1991) and valanginian– lower aptian (vavrdová, 1964). also, s. penicillata was discovered in the local record in the lower hauterivian (e.g., ibrahim & schrank, 1996). these dinocysts normally occur in the jurassic but cretaceous records were also known. zobaa et al. (2013) suggested a middle to late jurassic age based on the presence of c. combazii (not illustrated by photomicrographs) being no younger than the callovian. they noted the absence of any angiosperm pollen in this interval. the presumed oxidation in the carbonate body do not contrast the palynomorph occurrences observed by zobaa et al. (2013), except that some palynomorphs might have expected to be oxidized and/or degraded. on the basis of the discussions in the above paragraphs, the present miospores of the kharita formation can be correlated to a middle-late albian age. 6.2. palaeoenvironmental inferences the relative percentages of palynomorphs and palynofacies categories of the kharita formation, as plotted on smp and app ternary plots (figs. 6a, b), suggest an oxic, to dysoxic– suboxic, deltaic environment for deposition, near fluvial sources (tyson, 1995). the low abundance of aom in most samples may suggest shallow shelf sedimentation and dysoxic– suboxic conditions (e.g., dow & pearson, 1975; bujak et al., 1977; tyson, 1995; alaug et al., 2014). in this study, figure 6. a) smp (spores, pollen, microplankton) ternary diagram (after federova, 1977; duringer & doubinger, 1985; tyson, 1995; traverse, 2007); b) app (aom/palynomorphs/phytoclasts) ternary diagram of the total palynological organic matter (tpom) in the study borehole, with the roman numbers indicating the fields explained by tyson (1995, p. 446, 447). red stars refer to the present eleven investigated samples. g eologia c roatica 23khalaf and mahmoud: albian biostratigraphy and palaeoecology of the sharib-1x borehole (northern egypt): insights from palynomorphs ... aom is regarded as including all particulate structureless components at the scale of light microscopy that could represent a diverse array of marine or non-marine origins. in marine sediments, aom is mainly derived from phytoplankton and bacteria (see tyson, 1995). the term “amorphous” is used by palynologists in a descriptive sense, regardless of origin and derivation. the low abundance and low diversity of dinoflagellate cysts confirm deposition in very shallow marine, to coastal, settings (e.g., tyson, 1993). the redox states seem to have influenced the dinoflagellates association in the forma­ tion, as seen from their lower diversities as recorded by omran et al. (1990). sensitive, heterotrophic species of dinoflagellates may undergo degradation due to excess oxygen in the depositional basin. such heterotrophic cysts live in areas influenced by freshwater influx with rich nutrients (zonneveld et al., 2007, 2009). higher amounts of aom at two horizons, as seen from samples 1 and 4 (depths 2078 m and 2002 m), are typical of sediments deposited in anoxic marine settings (summer­ hayes, 1987; tyson, 1987). the temporal change in the m/c ratio is useful in identifying a proximal-distal trend in sedimentation (e.g., pittet & gorin, 1997). accordingly, the observed low m/c values, across most of the investigated borehole section, confirm marginal (proximal) settings. excep­ tionally, at the basal and upper parts of the kharita formation, where the m/c ratio increases, more open marine settings may have occurred, as this ratio is relatively affected by taphonomic processes, especially biodegradation (bombardiere & gorin, 2000), besides the borehole's setting (see geological setting section). during the albian–cenomanian era, egypt's northern basins featured fluvio­deltaic to shallow marine habitats. the kharita formation's sedimentary successions were mostly made up of mixed siliciclastic and minor carbonate rocks. this caused difficult conditions for various calcareous nannofossils and foraminiferal assemblages (mansour et al., 2022). also, because of the nature of the cutting rock samples used in this study, it is often difficult to ensure that a given species' first appearance datum (fad) and last appea­ rance datum (lad) correspond to its true inception and extinction due to taphonomic biases and/or lithologic facies control. as a result, the recorded real lowest occurrence (lo) and highest occurrence (ho) values are utilized here rather than the first and last appearances. to prevent caving, the palynomorph zones are usually delineated using the highest occurrence (ho) data of the marker types. however, tested lowest occurrence (lo) data are occasionally employed in the absence of ho of marker taxa (fig. 5a) (mahmoud et al., 2019). 6.3. degradation in the top kharita formation post-depositional bio-oxidation of wood phytoclasts in coastal sediments with varying water tables was previously documented by pocock (1982). in addition, preservation in sand-rich sediments might explain the increase in blackwood and the subsequent decline in the brown-to-black wood ratio that drops out offshore (götz et al., 2005, 2008; habib, 1982; summerhayes, 1987; tyson, 1989). zobaa et al. (2013, p. 60, fig. 7) described highly mature to overmature gas-prone/inert materials in most of the interval, manifested by the dominance of opaques, associated with medium to dark brown palynomorphs and a low aom content. they attributed this palynofacies, in relatively coarse-grained, high energy organic-poor facies, to a shallow marine, slightly oxic to suboxic, environment. we believe that these characteristics are suggestive of pronounced oxidation, which may have led to a partial degradation of the accumulated organic matter. in this work, we re-investigated two samples (nos. 10 and 11, at depths of 1868 m to 1850 m), that are located within this opaque­ dominated interval (fig. 7). sample no. 10, only a few metres figure 7. photomicrograph showing the main constituents of the recorded palynofacies in the investigated samples. g eo lo gi a c ro at ic a 24 geologia croatica 78/1 above the sample that contains their lowest opaques at 1871 m, yielded frequent records of afropollis and other angiosperms. in contrast, sample 11 lacks pollen, although it also has a relatively very low opaque content. we attributed that to the impact of the environmental restriction (i.e., marginal setting) rather than being due to oxidation of the organic matter, particularly in such a carbonate environment where flowering plants are likely to be scarce or absent. note that the m/c ratio declines to a minimum in this sample. angiosperms increase in frequency in association with the increase in the m/c ratio, namely away from the impact of the environmental restriction. based on the foregoing discussion, the relatively lower percentages of opaques (see fig. 7) might reflect a low to moderate oxidation impact. consequently, most of the palynomorph association can be preserved. however, biodegradation, due to the destructive activity of bacteria and fungi in the fossil pollen grains and spores is common, (e.g., tiwari & singh, 1986) and cannot be attributed to oxidation or other physicochemical processes (elsik, 1966). the general, shallow marine, nature of the kharita formation may explain the recorded low-diversity angiosperm association in the investigated non-oxidized interval of the sharib-1x borehole. the location of the borehole, at the northern edge of the east-west trending sharib-sheiba high regional uplift, implies deposition of the sediments at such shallower settings. this local regressive episode coincides with the late aptian–albian regional uplift, which affected the majority of northern egypt (meshref, 1990). degradation of palynomorphs in the investigated residues is not expected since the present processing technique completely avoided using oxidizing agents, the excessive use of which may lead to degradation (schrank, 1988). 6.4. palaeogeographic significance of the kharita miospores the presence of elaterates, along with other miospores, reflects the affinity of the sharib­1x palynoflora with the albian– cenomanian african–south america (asa) palynofloral pro­ vince, first introduced by herngreen (1974) and sub se­ quently recognized in south american and african countries, the middle east, bahamas islands, southern alps, westernmost china and papua-new guinea (herngreen & jimenez, 1990; dino et al., 1999). this province was previously inferred and discussed in egyptian literature (e.g., deaf et al., 2014). our data clearly reflect the influence of the break­up of the continents of africa and south america and the gradual opening of the atlantic ocean in the late aptian to early albian, and the resultant global palaeoclimate change near the equator (fig. 8) from the earlier relative drought to humid conditions. these conditions were recently documented from the doseo basin, central african rift system (dou et al., 2024), where gymnosperms (araucariacites and cycadopites here) and fern spores (deltoidospora and triplanosporites here) account for a high proportions, with a small amount of angiosperms. 7. conclusions terrestrial albian sporomorphs, dominated by pteridophytes and gymnosperms, were recorded from the sharib-1x borehole. the afropollis jardinus pollen and the elaterates (elaterocolpites castelainii, elaterosporites klaszii) confirm an albian age of the investigated interval of the kharita formation. miospores therefore can be a powerful tool in the biostratigraphy of sequences that were deposited in regressive shallow marine conditions (the case herein), resulting in a paucity of dinocyst assemblages and other microplankton. age assessments based on palynomorphs, especially at the jurassic/cretaceous transition, require a comprehensive synopsis of the ranges of the recorded species. looking at the whole palynofacies is necessary to infer the degradation of palynomorphs. care should be considered when applying terrestrial pollen and spores in biostratigraphy if the palynoflora shows evidence of oxidation, environmental restriction or biodegradation effects. these factors may result in incomplete palynofloras being recorded, as discovered in figure 8. palaeogeographic map for the beginning of the albian stage, 113 ma (after hay et al., 1999; the plate tectonic maps are composed from the data files used for the publication), indicating approximate position of egypt (red star). ages are taken after the latest issue of the “international chronostratigraphic chart” (cohen et al., 2013; updated). g eologia c roatica 25khalaf and mahmoud: albian biostratigraphy and palaeoecology of the sharib-1x borehole (northern egypt): insights from palynomorphs ... the carbonate interval, at the top of the kharita formation in the investigated borehole. this can manifest by the rarity of certain palynomorphs, probably the angiosperms, the paucity of aom, the occurrence of extraordinarily abundant opaques, and the low palynomorph diversities. these carbonates are not widespread in the regional record, only occur as thin beds; and their thickness in this borehole (~30 m thick) needs further investigation. however, the jurassic carbonates of the masajid formation are much thicker and measure a few hundreds of metres. in general, the subsurface stratigraphic column of the northern western desert of egypt shows thick carbonates of the medewar formation (lateral equivalent of bahariya figure 9. scale bar = 20 μm, except 12, 13, 14, 16 and 20 scale bar =50 μm. 1 – dictyophyllidites harrisii couper, 1958, depth: 2002 m, a, no.: 4, indices: 10.5/83.6. 2 – deltoidospora hallii miner, 1935, depth: 2002 m, a, no.: 4, indices: 7.6/92.3. 3 – microfoveolatisporites sp., depth: 1956 m, c, no.: 5, indices: 14.5/95.5. 4 – densoisporites sp., depth: 1923 m, a, no.: 6, indices: 11.5/87. 5 – converrucosisporites sp., depth: 1883 m, a, no.: 9, indices: 12/95. 6 – verrucosisporites sp., depth: 1956 m, a, no.: 5, indices: 6/93. 7 – triplanosporites sp., depth: 1868 m, a, no.: 10, indices: 23/102. 8 – converrucosisporites sp., depth: 1956 m, b, no.: 5, indices: 22.3/105. 9 – prasinophycean phycomata, depth: 2078 m, a, no.: 1, indices: 22/107.5. 10 – tetrad pollen depth: 2002 m, a, no.: 4, indices: 10.5/81.6. 11 – classopollis sp., depth: 2002 m, a, no.: 4, indices: 6.4/94. 12 – callialasporites sp., depth: 1850 m, b, no.: 11, indices: 12/85. 13 – callialasporites sp. cf. c. trilobatus (balme, 1957) sukh dev, 1961, depth: 1889 m, b, no.: 8, indices: 10.5/97.8. 14 – callialasporites trilobatus (balme) sukh dev, 1961, depth: 1868 m, a, no.: 10, indices: 15/105.5. 15 – monosulcites sp., depth: 1889 m, b, no.: 8, indices: 13.5/91.8. 16 – ?callialasporites sp., depth: 2060 m, b, no.: 2, indices: 9.3/90. 17, 18, 19 – bisaccate pollen, depth: 1889 m, a, no.: 8, indices: 11.7/90.5; depth: 2060 m, a, no.: 2, indices: 11.6/91.8; depth: 1956 m, b, no.: 5, indices: 12/99.7. 20 – callialasporites dampieri (balme, 1957) sukh dev, 1961, depth: 2060 m, a, no.: 2, indices: 11.4/84. g eo lo gi a c ro at ic a 26 geologia croatica 78/1 formation) just above the kharita formation. the overall recorded palynomorphs reveal that the kharita formation is deposited in a marginal, oxic to dysoxic–suboxic, environment. it may have shifted to distal settings, at the base and top of the kharita formation, where the marine elements and aom increase in abundance. at these levels, greater counts of the angiosperm were seen. this may confirm that the preservation of these angiosperms may have affected by the (restricted) environment. the kharita palynofloras bear great affinity to asa palynofloristic province and reflect the influence of the break-up of the continents of africa and south america and the gradual opening of the atlantic ocean in the late aptian to early albian, and the resultant global palaeoclimate change near the equator to humid conditions. figure 10. scale bar = 20 μm, except 5 and 6 scale bar = 10 μm and 3, 7 and 15 scale bar =50 μm. 1, 2, 3 – elaterosporites klaszii (jardiné & magloire) jardiné, 1967, depth: 1923 m, b, no.: 6, indices: 7.7/91.7; depth: 1911 m, a, no.: 7, indices: 9.1/102.5; depth: 2060 m, b, no.: 2, indices: 9/90.8. 4 – retimonocolpites ghazalii ibrahim, 2002a, depth: 1868 m, c, no.: 10, indices: 14.5/86.5. 5 – afropollis jardinus doyle et al., 1982, depth: 2002 m, a, no.: 4, indices: 12.5/93.7. 6 – afropollis aff. jardinus doyle et al., 1982, depth: 1956 m, b, no.: 5, indices: 12.7/85.6. 7 – escharisphaeridia sp., depth: 1868 m, b, no.: 10, indices: 9.6/95.5. 8, 14 – cleistosphaeridium spp., depth: 2078 m, a, no.: 1, indices: 16.4/107; depth: 1883 m, a, no.: 9, indices: 18.2/86.5. 9 – ?kallosphaeridium sp. (note the a attached – like archeopyle), depth: 1889 m, a, no.: 8, indices: 17/99.5. 10 – meiourogonyaulax sp., depth: 1889 m, a, no.: 8, indices: 19/111.6. 11 – subtilisphaera sp., depth: 1923 m, a, no.: 6, indices: 19.4/105.7. 12 – florentina mantellii (davey & williams) davey & verdier, 1973, depth: 2060 m, b, no.: 2, indices: 9/91.2. 13 – indet. dinoflagellate cyst, depth: 2078 m, a, no.: 2, indices: 12/86.7. 15, 17 – microforaminiferal linings, depth: 2078 m, a, no.: 1, indices: 12.7/108.8; depth: 2078 m, a, no.: 1, indices: 11.5/97.8. 16 – ?systematophora sp., depth: 1923 m, b, no.: 6, indices: 14/106.5. 18 – cf. operculodinium sp. depth: 2078 m, a, no.: 1, indices: 7/98. 19 – florentinia sp., depth: 1889 m, b, no.:8, indices: 13.4/112. g eologia c roatica 27khalaf and mahmoud: albian biostratigraphy and palaeoecology of the sharib-1x borehole (northern egypt): insights from palynomorphs ... acknowledgement thanks are due to the egyptian general petroleum corporation (e.g.p.c.) for providing the material and borehole log for the present work. we appreciate the suggestions of two anonymous reviewers for their informative and helpful remarks. the authors would like to thank tea fluksi (managing editor, geologia croatica) for her assistance and remarks kindely offered during the publication procedures. references aboul ela, n.m. & tahoun, s.s. (2010): dinoflagellate cyst stratigraphy of the subsurface middle-upper jurassic/lower cretaceous sequence in north sinai, egypt.– in: fifth international conference on the geology of the tethys realm. south valley university, 85­115. aboul ela, n., tahoun, s.s. & raafat, a. (2020): the cretaceous (barremian–maastrichtian) palynostratigraphy and palynofacies of the drazia­1 well, north egypt.– palynology, 44, 94–113. https://doi.org/10. 1080/01916122.2018.1510858 alaug, a., mahmoud, m.s., deaf, a.s. & al­ameri, t.k. (2014): palynofacies, organic geochemical analyses and hydrocarbon potential of some upper jurassic–lower cretaceous rocks, the sabatayn­1 borehole, central yemen.– arab. j. geosci., 7, 2515–2530. https://doi.org/10.1007/ s12517­013­0961­y batten, d.j. (1996): palynofacies and palaeoenvironmental interpretation.– in: jansonius, j. & mcgregor, d.c. (eds.): palynology: principles and applications. american association of stratigraphic palynologists foundation, college station, 3, 1011­1064. batten, d.j. & uwins, p.j.r. (1985): early–late cretaceous (aptian–cenomanian) palynomorphs.– j. micropalaeont., 4/1, 151–168. https://doi. org/10.1144/jm.4.1.151 bayoumi, a.i. & lotfy, h.i. (1989): modes of structural evolution of abu gharadig basin, western desert of egypt as deduced from seismic data.– j. african earth sci., 9, 273–287. https://doi.org/10.1016/08995362(89)90070­5 bombardiere, l. & gorin, g.e. (2000): stratigraphical and lateral distribution of sedimentary organic matter in upper jurassic carbonates of se france.– sediment. geol., 132, 177–203. https://doi.org/10.1016/ s0037-0738(00)00006-3 bosworth, b. & tari, g. (2021): hydrocarbon accumulation in basins with multiple phases of extension and inversion: examples from the western desert (egypt) and the western black sea.– solid earth, 12, 59–77. https://doi.org/10.5194/se­12­59­2021 brenner, g.j. (1968): middle cretaceous spores and from northeastern peru.– pollen et spores 10, 341–382. bujak, j.p., barss, m.s. & williams, g.l. (1977): offshore east canada's organic type and color and hydrocarbon potential.– oil gas j., 75, 198–201. cohen, k.m., finney, s.c., gibbard, p.l. & fan, j. x. (2013): the ics international chronostratigraphic chart.– episodes, 36, 199–204. https:// doi.org/10.18814/epiiugs/2013/v36i3/002 deaf, a.s., harding, i.c. & marshall, j.e.a. (2014): cretaceous (albian–?earlysantonian) palynology and stratigraphy of the abu tunis 1x borehole, northern western desert, egypt.– palynology, 38, 51–77. https://doi.org/10.1080/01916122.2013.828662 deaf, a., tahoun, s., gentzis, t., carvajal­ortiz, h., harding, i.c., marshall, j.e. & ocubalidet, s. (2020): organic geochemical, palynofacies, and petrographic analyses examining the hydrocarbon potential of the cretaceous (albian) kharita formation in the matruh basin, northwestern egypt.– mar. pet. geol., 112:104087. https://doi.org/10.1016/j.marpetgeo.2019.104087 dino, r., pocknall, d.t. & dettmann, m.e. (1999): morphology and ultrastrucutre of elater-bearing pollen from the albian to cenomanian of brazil and ecuador: implications for botanical affinity.– rev. palaeobot. palynol., 105, 201­235. dou, l., zhang, x., xiao, k., xi, d., du, y., wang, l., hu, j., hu, y. & zheng, q. (2024): early cretaceous (aptian to albian) vegetation and climate change in central africa: novel palynological evidence from the doseo basin.– geol. j., 59/2, 441–467. https://doi.org/10.1002/gj.4873 dow, w.g. & pearson, d.b. (1975): organic matter in gulf coastal sediments.– in: offshore technology conference, dallas, otc­2343­ms. https://doi.org/10.4043/2343­ms doyle, j.a., jardine, s. & doerenkamp, a. (1982): afropollis, a new genus of early angiosperm pollen, with notes on the cretaceous palynostratigraphy and palaeoenvironments of northern gondwana.– bull. centres recher. explor. prod. elf aquitaine, 6, 39–117. duringer, p. & doubinger, j. (1985): la palynologie: un outil de caractérisation des faciès marins et continentaux à la limite muschelkalk supérieur-lettenkohle.– sciences géologiques, bulletins et mémoires, 38, 19–34. https://doi.org/10.3406/sgeol.1985.1687 e.g.p.c. (1992): western desert, oil and gas fields (a comprehensive overview). cairo, egypt.– egyptian general petroleum corporation, 431 pp. el atfy, h. (2021) palynofacies as a palaeoenvironment and hydrocarbon source potential assessment tool: an example from the cretaceous of north western desert, egypt.– palaeobiodiversity and palaeoenvironments, 101, 35–50. https://doi.org/10.1007/s12549­020­00474­9 el atfy, h., mostafa, a., maher, a., mahfouz, k. & hosny, a. (2019): early cretaceous biostratigraphy and palaeoenvironment of the northern western desert, egypt: an integrated palynological and micropalaeontological approach.– palaeontogr. abt. b, 299/1-6, 103–132. https://doi.org/10.1127/palb/2019/0064 el atfy, h.e., coiffard, c., el beialy, s.y. & uhl, d. (2023): vegetation and climate change at the southern margin of the neo-tethys during the cenomanian (late cretaceous): evidence from egypt.– plos one, 18, e0281008. https://doi.org/10.1371/journal.pone.0281008 el beialy, s.y. & al­hitmi, h.h. (1994): micropalaeontology and palynology of the lower and middle cretaceous thamama and wasia groups, dk-c well, dukhan oil field, western qatar.– sci. geol. bull., 47, 67–95. el beialy, s.y., el atfy, h.s., zavada, m.s., el khoriby, e.m. & abu­zied, r.h. (2010): palynological, palynofacies, palaeoenvironmental and organic geochemical studies on the upper cretaceous succession of the gptsw-7 well, north western desert. egypt.– mar. pet. geol., 27, 370–385. https://doi.org/10.1016/j.marpetgeo.2009.10.006 el shamma, a.e., obied, f.l. & mohammed, s.a. (1999): neocomian–cenomanian palynozones of some subsurface rocks in north western desert, egypt.– in:1st international conference on the geology of africa. assiut university, egypt, 1, 65–102. elsik, w.c. (1966): biologic degradation of fossil pollen grains and spores.– micropalaeontol., 12/4, 515–518. http://dx.doi.org/10.2307/1484797 federova, v.a. (1977): the significance of the combined use of microphytoplankton, spores, and pollen for differentiation of multi­facies sediments.– in: samoilovich, s.r. & timoshina, n. (eds.): questions of phytostratigraphy. trudy neftyanoi nauchnoissledovatelskii geologorazvedochnyi institute (vnigri), leingrad, 398, 70–88. fensome, r.a., williams, g.l. & macrae, r.a. (2019): the lentin and williams index of fossil dinoflagellates: 2019 edition.– aasp contributions series, 50. american association of stratigraphic palynologists foundation, 1173 p. gentzis, t., carvajal, h., deaf, a. & tahoun, s.s. (2018). multi­ proxy approach to screen the hydrocarbon potential of the jurassic succession in the matruh basin, north western desert, egypt.– int. j. coal geol., 190, 29–41. https://doi.org/10.1016/j.coal.2017.12.001 gentzis, t., carvajal­ortiz, h., tahoun, s., deaf, a. & ocubalidet, s. (2019): organic facies and hydrocarbon potential of the early-middle kharita formation in the abu gharadig basin, egypt as demonstrated by palynology, organic petrology, and geochemistry.– int. j. coal geol., 209, 27–39. https://doi.org/10.1016/j.coal.2019.05.002 ghorab, m.a., ebeid, z. & tawfik, n. (1971): on the stratigraphy of the northeastern corner of the western desert.– in: proceedings of the ninth annual meeting of the geological society of egypt, giza. https://doi.org/10.1080/01916122.2018.1510858 https://doi.org/10.1080/01916122.2018.1510858 https://doi.org/10.1007/s12517-013-0961-y https://doi.org/10.1007/s12517-013-0961-y https://doi.org/10.1144/jm.4.1.151 https://doi.org/10.1144/jm.4.1.151 https://doi.org/10.1016/0899-5362(89)90070-5 https://doi.org/10.1016/0899-5362(89)90070-5 https://doi.org/10.1016/s0037-0738(00)00006-3 https://doi.org/10.1016/s0037-0738(00)00006-3 https://doi.org/10.5194/se-12-59-2021 https://doi.org/10.18814/epiiugs/2013/v36i3/002 https://doi.org/10.18814/epiiugs/2013/v36i3/002 https://doi.org/10.1080/01916122.2013.828662 https://doi.org/10.1016/j.marpetgeo.2019.104087 https://doi.org/10.1016/j.marpetgeo.2019.104087 https://onlinelibrary.wiley.com/authored-by/dou/lirong https://onlinelibrary.wiley.com/authored-by/zhang/xinshun https://onlinelibrary.wiley.com/authored-by/xiao/kunye https://onlinelibrary.wiley.com/authored-by/xi/dangpeng .wiley.com/authored-by/du/yebo https://onlinelibrary.wiley.com/authored-by/wang/li https://onlinelibrary.wiley.com/authored-by/hu/jie https://onlinelibrary.wiley.com/authored-by/hu/ying https://onlinelibrary.wiley.com/authored-by/zheng/qianyu https://doi.org/10.1002/gj.4873 https://doi.org/10.4043/2343-ms https://doi.org/10.3406/sgeol.1985.1687 https://doi.org/10.1007/s12549-020-00474-9 http://dx.doi.org/10.1127/palb/2019/0064 https://doi.org/10.1371/journal.pone.0281008 https://doi.org/10.1016/j.marpetgeo.2009.10.006 http://dx.doi.org/10.2307/1484797 https://doi.org/10.1016/j.coal.2017.12.001 https://doi.org/10.1016/j.coal.2019.05.002 g eo lo gi a c ro at ic a 28 geologia croatica 78/1 götz, a.e., szulc, j. & feist­burkhardt, s. (2005): distribution of sedimentary organic matter in anisian carbonate series of s poland: evidence of third order sea­level fluctuations.– int j earth sci, 94, 267–274. https://doi.org/10.1007/s00531­005­0469­0 götz, a.e., feist­burkhardt, s. & ruckwied, k. (2008): palynofacies and sea level changes in the upper cretaceous of the vocontian basin, southeast france.– cretac. res., 29, 1047–1057. https://doi.org/10.1016/j. cretres.2008.05.029 guiraud, r., bosworth, w., thierry, j. & delplanque, a. (2005): phanerozoic geological evolution of northern and central africa: an overview.– j. african earth sci., 43, 83–143. https://doi.org/10.1016/j. jafrearsci.2005.07.017 habib, d. (1982): sedimentary supply origin of cretaceous black shales.– in: schlanger, s.o. & cita, m.b. (eds.): nature and origin of cretaceous carbon-rich facies. academic press, london, 113–127. hantar, g. (1990): north western desert.– in: said, r. (ed.): the geology of egypt. balkema, rotterdam, 293-319. hasenboehler, b. (1981): e`tude paléobotanique et palynologique de l'albien et du cénomanien du bassin occidental portugais au sud de l'accident de nazaré (province d'estremadure), portugal.– thèse 3ème cycle, univ. paris, 6, 317 p. hay, w.w., de conto, r., wold, c.n., wilson, k.m., voigt, s., schulz, m., wold­rossby, a., dullo, w.c., ronov, a.b., balukhovsky, a.n. & soeding, e. (1999): alternative global cretaceous palaeogeography.– in: barrera, e. & johnson, c. (eds.): the evolution of cretaceous ocean/climate systems. geol. soc. am. spec pap., 332, 1–47. herngreen, g.f.w. (1973): palynology of albian–cenomanian strata of borehole 1-qs-1-ma, state of maranhão, brazil.– pollen et spores, 15, 515­555. herngreen, g.f.w. (1974): middle certaceous palynomorphs from northeastern brazil.– sci. geol. bull., 27, 101–116. herngreen, g.f.w. (1975): palynology of middle and upper cretaceous strata in brazil.– mededelingen rijks geologische dienst, 26, 39–91. herngreen, g.f.w. & jimenez, h.d. (1990): dating of the cretaceous une formation, colombia and the relationship with the albian–cenomanian african–south american microfloral province.– rev. palaeobot. palynol., 66, 345–359. https://doi.org/10.1016/0034­6667(90)90046­l hochuli, p.a. (1981): north gondwanan floral elements in lower to middle cretaceous sediments of the southern alps (southern switzerland, northern italy).– rev. palaeobot. palynol., 35, 337­358. ibrahim, m.i.a. & schrank, e. (1996): palynological studies on the late jurassic–early cretaceous of the kahraman-1 borehole, northern western desert, egypt. géology de l àfrique et de l àtlantique sud: bulletin des centres de recherches exploration-production elf-aquitaine.– mémoire, 16, 611-629. jardiné, p.e., fraser, w.t., lomax, b.h. & gosling, w.d. (2015): the impact of oxidation on spore and pollen chemistry.– j. micropalaeontol., 34, 139–149. http://dx.doi.org/10.1144/jmpalaeo2014­022 jardiné, s. (1967): spores a expansion en forme d'elateres du cretace moyen d'afrique occidentale.– rev. palaeobot. palynol., 1, 235–258. https:// doi.org/10.1016/0034­6667(67)90126­1 jardiné, s. & magloire, l. (1965): palynologie et stratigraphie du crétacé des bassins du sénégal et de côte d'ivoire.– mémoires du b.r.g.m., 32, 187–245. kaska, h.v. (1989): a spore and pollen zonation of early cretaceous to tertiary non­marine sediments of central sudan.– palynology, 54, 79–90. lawal, o. & moullade, m. (1986): palynological biostratigraphy of cretaceous sediments in the upper benue basin, ne nigeria.– revue de micropalaeontologie, 29, 61–83. lotfy, m.m., abd el gawad, e.a. & abdelghafar, a. (2020): hydrocarbon source-rock potential of the jurassic succession in eastern part of the north western desert, egypt.– egypt j. petrol., 29/3, 243–249. https://doi.org/10.1016/j.ejpe.2020.09.002 mahmoud, m.s. (1989): palynological studies on some jurassic­lower cretaceous sedimentary rocks of north-western desert, egypt and their stratigraphic significance.– phd thesis, faculty of science, assiut university, egypt, 214 p. mahmoud, m.s. & deaf, a.s. (2007): cretaceous palynology (spores, pollen and dinoflagellate cysts) of the siqeifa 1­x borehole, northern egypt.– revista italiana di micropalaeontología e stratigrafia, 113, 203– 221. https://doi.org/10.13130/2039­4942/5871 mahmoud, m.s., deaf, a.s., tamam, m.a. & khalaf, m.m. (2019): revised (miospores-based) stratigraphy of the lower cretaceous succession of the minqar-ix borehole, shushan basin, north western desert, egypt: biozonation and correlation approach.– j. african earth sci., 151, 18–35. https://doi.org/10.1016/j.jafrearsci.2018.11.019 mahmoud, m.s., khalaf, m.m., moawad, a.r.m.m. & temraz, a.a. (2023): early cretaceous palynoflora from palaeotropics of ne african (correlation and significance): an example from the shushan basin, egypt.– ital. j. geosci., 142, 165–182. https://doi.org/10.3301/ ijg.2023.10 mansour, a., wagreich, m., gier, s., gentzis, t., kloetzli, u., tahoun, s.s. & elewa, a.m.t. (2021): climate variability and palaeoceanography during the late cretaceous: evidence from palynology, geochemistry and stable isotopes. analyses from the southern tethys.– cretaceous research, 126, 104831. https://doi.org/10.1016/j.cretres. 2021.104831 mansour, a., wagreich, m., ahmed, m.s., tahoun, s.s. & gentzis, t. (2022): short-term sea-level changes and sequence stratigraphy of the mid-cretaceous kharita formation reservoirs in egypt: insights from geochemical and palynological data.– acs omega. 31, 27573–27586. https://doi.org/10.1021/acsomega.2c03154 meshref, w. (1990): tectonic framework.– in said, r. (ed.). the geology of egypt. rotterdam, balkema. meshref, w. (1996): createcous tectonics and its impact on exploration northern egypt.– geological society of egypt special publication, 2, 199–214. millioud, m.e., williams, g.l. & lentin, j.k. (1975): stratigraphic range charts of selected cretaceous dinoflagellates.– aasp contributions series, 4, 65–71. müller, j. (1966): montane pollen from the tertiary of nw borneo, blumea.– biodiversity, evolution and biogeography of plants, 14, 231–235. norton, p. (1967): rock stratigraphic nomenclature of the western desert.– internal report, pan­american u.a.r. oil company (now amoco), cairo, 18 p. omran, a.m., soliman, h.a. & mahmoud, m.s. (1990): early cretaceous palynology of three boreholes from northern western desert, egypt.– rev. palaeobot. palynol., 66, 293–312. https://doi.org/10.1016/ 0034­6667(90)90044­j phipps, d. & playford, g. (1984): laboratory techniques for extraction of palynomorphs from sediments.– papers of the department of geology, university of queensland, 11, 1–23. pittet, b. & gorin, e. (1997): distribution of sedimentary organic matter in a mixed carbonate-siliciclastic platform environment: oxfordian of the swiss jura mountains.– sedimentology, 44, 915–937. https://doi.org/10.1046/j.1365­3091.1997.d01­58.x pocock, s.a.j. (1982): identification and recording of particulate sedimentary organic matter.– in: staplin, d.j. et al. (eds.): how to assess maturation and palaeotemperatures. society of economic palaeontologists and mineralogists, short course, 7, 13–131. regali, m.s.p. & viana, c.f. (1989): late jurassic–early cretaceous in brazilian sedimentary basins: correlation with the international standard scale.– petrobras brasiliero, rio de janeiro, 95 p. regali, m.s.p., uesugui, n. & santos, a.s. (1974): palinologia dos sedimentos meso-cenozoicos do brasil (i & ii).– boletim tecnico da petrobras, 17, 177–191, 263–301. saad, a., abdel fattah, th., holial, h. & diab, a.i. (2023): exploration of new hydrocarbon leads in the eastern flank of abu gharadig basin, north western desert, egypt.– alex. eng. j., 66, 669–690. https:// doi.org/10.1016/j.aej.2022.12.020 https://doi.org/10.1007/s00531-005-0469-0 https://www.sciencedirect.com/journal/cretaceous-research https://doi.org/10.1016/j.cretres.2008.05.029 https://doi.org/10.1016/j.cretres.2008.05.029 https://doi.org/10.1016/j.jafrearsci.2005.07.017 https://doi.org/10.1016/j.jafrearsci.2005.07.017 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0210 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0210 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0210 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0210 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0210 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0215 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0215 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0215 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0215 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0215 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0215 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0215 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0215 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0215 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0215 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0215 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0215 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0215 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0215 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0215 https://doi.org/10.1016/0034-6667(90)90046-l http://dx.doi.org/10.1144/jmpalaeo2014-022 https://doi.org/10.1016/0034-6667(67)90126-1 https://doi.org/10.1016/0034-6667(67)90126-1 https://doi.org/10.1016/j.ejpe.2020.09.002 https://doi.org/10.13130/2039-4942/5871 https://doi.org/10.1016/j.jafrearsci.2018.11.019 https://doi.org/10.3301/ijg.2023.10 https://doi.org/10.3301/ijg.2023.10 https://doi.org/10.1016/j.cretres.2021.104831 https://doi.org/10.1016/j.cretres.2021.104831 https://doi.org/10.1021/acsomega.2c03154 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0290 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0290 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0290 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0290 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0290 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0290 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0290 http://refhub.elsevier.com/s0035-1598(17)30010-7/sbref0290 https://doi.org/10.1016/0034-6667(90)90044-j https://doi.org/10.1016/0034-6667(90)90044-j https://doi.org/10.1046/j.1365-3091.1997.d01-58.x https://doi.org/10.1046/j.1365-3091.1997.d01-58.x https://doi.org/10.1016/j.aej.2022.12.020 https://doi.org/10.1016/j.aej.2022.12.020 g eologia c roatica 29khalaf and mahmoud: albian biostratigraphy and palaeoecology of the sharib-1x borehole (northern egypt): insights from palynomorphs ... said, r. (1962): the geology of egypt.– elsevier, amsterdam, 177 p. said, r. (1990): the geology of egypt.– balkema, rotterdam, 733 p. schlumberger (1984): the western desert.– in: well evolution conference, egypt. schlumberger (1995): the western desert.– well evolution conference, egypt. schrank, e. (1988): effects of chemical processing on the preservation of peridinioid dinoflagellates: a case from the late cretaceous of ne africa.– rev. palaeobot. palynol., 56, 123–140. schrank, e. & ibrahim, m.i.a. (1995): cretaceous (aptian–maastrichtian) palynology of foraminifera-dated boreholes (krm-1, ag-18) in northwestern egypt.– berliner geowiss. abh. a, 177, 1–44. schrank, e. & mahmoud, m.s. (1998): palynology (pollen, spores and dinofglagellates) and cretaceous stratigraphy of the dakhla oasis, central egypt.– j. afr. earth sci., 26, 167–193. smelror, m., århus, n., meléndez, g.l.m. & lardies, m.d. (1991): a reconnaissance study of bathonian to oxfordian (jurassic) dinoflagellates and acritarchs from the zaragoza region (ne spain) and figueira da foz (portugal).– revista española de micropalaeontología, 23, 47–82. soliman, a. & el atfy, h. (2023): the history of palynology in egypt.– palynology, 48/2, 2273940. https://doi.org/10.1080/01916122.2023.22739 40 summerhayes, c.p. (1987): organic­rich cretaceous sediments from the north atlantic.– in: brooks, j. & fleet, a.j. (eds.): marine petroleum source rocks. geological society, london, 26, 301–316. tahoun, s.s. (2012): palynostratigraphical and palaeoenvironmental significance of a palynomorphs assemblage from the cenomanian of north western desert, egypt.– eg. j. palaeontol. 12, 73–95. tahoun, s.s. & ied, i.m. (2019): a cretaceous dinoflagellate cyst palynozonation of northern egypt.– palynology. 43, 394–410. https://doi.org/1 0.1080/01916122.2018.1449029 tahoun, s.s., ibrahim, m.i.a. & kholeif, s. (2012): palynology and palaeoenvironments of middle jurassic to cenomanian successions, alamein-ix well, north western desert, egypt.– rev. esp. micropalaeontology, 44, 57–78. tahoun, s.s., mostafa, t.f., makled, w.a. & saleh, r.a. (2015): palynomorph biostratigraphy of the cretaceous (hauterivian–lower cenomanian) of the south sallum well, north western desert, egypt.– arab. j. geosci., 8, 9205–9219. http://dx.doi.org/10.1007/s12517­015­1861­0 tahoun, s.s., deaf, a.s., gentzis, t. & carvajal­ortiz, h. (2018): modified rgb based kerogen maturation index (kmi): correlation and calibration with classical thermal maturity indices.– int. j. coal geol. 190, 70–83. https://doi.org/10.1016/j.coal.2017.09.004 tassy, a., crouzy, e., gorini, c., rubino, j.l., bouroullec, j.l. & sapin, f. (2015): egyptian tethyan margin in the mesozoic: evolution of a mixed carbonate-siliciclastic shelf edge (from western desert to sinai).– mar pet geol, 68, 565–581. https://doi.org/10.1016/j.marpetgeo.2015.10.011 tiwari, r.s. & singh, v. (1986): palynological evidences for permo-triassic boundary in raniganj coalfield, damodar basin india.– in: samanta, b.k. (ed.): proc. 11th indian colloq. micropal., calcutta 1984, pt. 2, stratigraphy and microflora, bull. geol. min. metall. soc. india 54, 256–264. traverse, a. (2007): palaeopalynology, 2nd edition.– springer, dordrecht, 813 p. tyson, r.v. (1987): the genesis and palynofacies characteristics of marine petroleum source rocks.– in: brooks, j. & fleet, a.j. (eds.): marine petroleum source rocks. geological society, london, 26, 47–67. tyson, r.v. (1989): late jurassic palynofacies trends, piper and kimmeridge clay formations, uk onshore and northern north sea.– in: batten, d.j. & keen, m.c. (eds.): northwest european micropalaeontology and palynology. ellis horwood, chichester, 135–172. tyson, r.v. (1993): palynofacies analysis.– in: jenkins, d.g. (ed.): applied micropalaeontology. kluwer academic publishers, dordrecht, 153–191. http://dx.doi.org/10.1007/978­94­017­0763­3_5 tyson, r.v. (1995): sedimentary organic matter: organic facies and palynofacies.– chapman and hall, london, 615 p. http://dx.doi. org/10.1007/978­94­011­0739­6 vavrdová, m. (1964): microplankton from the tëŝin­hardiŝtŝ series (lower cretaceous): part i. dinoflagellates.– sb. geol. věd, palaeontol., sect. p, 4, 91–104. wepco (1971): final report and comopsite well log of the sharib-1x borehole.– western desert opertaing petroleum company. zobaa, m.k. & oboh­ikuenobe, f.e. (2018): the magnificent seven: the stratigraphically most important mid-cretaceous terrestrial palynofloral species in the north western desert, egypt.– j. iber. geol., 44, 243–255. https://doi.org/10.1007/s41513­018­0062­6 zobaa, m.k., el beialy, s.y., el-sheikh, h.a. & el beshtawy, m.k. (2013): jurassic–cretaceous palynomorphs, palynofacies, and petroleum potential of the sharib-1x and ghoroud-1x wells, north western desert, egypt.– j. african earth sci., 78, 51–65. http://dx.doi.org/10.1016/j.jafrearsci.2012.09.010 zonneveld, c.a.f., bockelmann, f.­d. & holzwarth, u. (2007): selective preservation of organic walled dinoflagellate cysts as a tool to quantify past net primary production and bottom water oxygen concentrations.– mar. geol., 237, 109–126. https://doi.org/10.1016/j.margeo.2006.10.023 zonneveld, k.a.f., chen, l., möbius, j. & mahmoud, m.s. (2009): environmental significance of dinoflagellate cysts from the proximal part of the po­river discharge plume (off southern italy, eastern mediterranean).– j. sea res., 62, 189–213. https://doi.org/10.1016/j.seares.2009.02.003 https://doi.org/10.1080/01916122.2023.2273940 https://doi.org/10.1080/01916122.2023.2273940 https://doi.org/10.1080/01916122.2018.1449029 https://doi.org/10.1080/01916122.2018.1449029 http://dx.doi.org/10.1007/s12517-015-1861-0 https://doi.org/10.1016/j.coal.2017.09.004 https://doi.org/10.1016/j.marpetgeo.2015.10.011 https://doi.org/10.1016/j.marpetgeo.2015.10.011 https://www.lyellcollection.org/journal/sp http://dx.doi.org/10.1007/978-94-017-0763-3_5 http://dx.doi.org/10.1007/978-94-011-0739-6 http://dx.doi.org/10.1007/978-94-011-0739-6 https://doi.org/10.1007/s41513-018-0062-6 http://dx.doi.org/10.1016/j.jafrearsci.2012.09.010 http://dx.doi.org/10.1016/j.jafrearsci.2012.09.010 https://doi.org/10.1016/j.margeo.2006.10.023 https://doi.org/10.1016/j.margeo.2006.10.023 https://doi.org/10.1016/j.seares.2009.02.003 1. introduction geothermal systems, which represent a renewable resource for energy and raw material production, vary considerably worldwide due to the different mechanisms governing their formation. they are classified according to their principal properties and characteristics, including their geological, hydrogeological, geochemical, and thermal aspects (moeck, 2014). a subset of geothermal systems is referred to as hydrothermal when the heat transfer mechanism involves circulating water, whether as liquid or vapour (ojha et al., 2021; khodayar & björnsson, 2024). in the study of hydrothermal systems, it is necessary to determine the origin of the fluid and the area of recharge, the heat transfer mechanism, the direction of fluid flow and the depth to which it descends, the geometry of the aquifer and its hydrogeological and thermal properties, and the conditions favouring the outflow of the thermal water. research of hydrothermal systems usually includes the application of an integrated multidisciplinary approach. the geological framework and tectonic evolution of the area influenced by the circulation of thermal fluids are typically recon a conceptual and numerical model of fluid flow and heat transport in the topusko hydrothermal system mirja pavić1, marco pola1, bojan matoš2,*, katarina mišić2, ivan kosović1, ivica pavičić2 and staša borović1 1 croatian geological survey, sachsova 2, 10000 zagreb, croatia 2 university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva ulica 6, 10000 zagreb, croatia; (*corresponding author: bojan.matos@rgn.unizg.hr) doi: 10.4154/gc.2024.14 abstract a comprehensive understanding of hydrothermal systems is often obtained through the integration of conceptual and numerical modelling. this integrated approach provides a structured framework for the reconstruction and quantification of fluid dynamics in the reservoir, thereby facilitating informed decision-making for sustainable utilisation and environmental protection of the hydrothermal system. in this study, an updated conceptual model of the topusko hydrothermal system (ths), central croatia, is proposed based on structural, geochemical, and hydrogeological analyses. the stratigraphic sequence and the structural framework of the ths were defined based on geological maps and field investigations. as depicted by hydrochemical and isotope analyses, the thermal waters in the topusko system (temperatures < 65 °c) are of meteoric origin and circulate in a carbonate aquifer. the ths receives diffuse recharge approximately 13 km s of topusko, where triassic carbonates crop out. gravity-driven regional groundwater circulation is favoured by regional thrusts that tectonically uplifted palaeozoic rocks of low permeability. these structures confine the fluid flow in the permeable, fractured and karstified triassic carbonates, favouring the northward circulation of the water. a regional anticline lifts the aquifer closer to the surface in topusko. open fractures in the anticline hinge zone increase the fracturing and permeability field of the aquifer, promoting the rapid upwelling of thermal water resulting in the topusko thermal springs. numerical simulations of fluid flow and heat transport corroborate the proposed conceptual model. in particular, a thermal anomaly was modelled in the topusko subsurface with temperature values of 31.3 °c and 59.5 °c at the surface and at the base of the thermal aquifer, respectively, approaching the field observations. these findings show that the circulation of topusko thermal water is influenced by regional and local geological structures suggesting that the enhanced permeability field in the discharge area enables the formation of the natural thermal springs. structed by combining regional and local field investigations and geophysical data (e.g., muffler & cataldi, 1978; flóvenz et al., 2012; kosović et al., 2023, 2024). they provide insights into the surface geometry of geological formations and fracture networks and the kinematics of fault systems that are consequently used for subsurface geological reconstructions, supported by 2d or 3d geological modelling. hydrogeochemical research is the requisite for understanding and managing geothermal aquifers. it involves continuous monitoring of the thermal water to evaluate baseline levels, track their changes, and assess the impact of water abstraction, which is crucial for resource protection and legislative compliance (hounslow, 1995; marini, 2000; mazor, 2004; heasler, 2009). analysis of groundwater chemistry and isotopic content aids in characterising hydrothermal systems, identifying water sources, estimating reservoir temperatures, and assessing potential mixing. hydrogeological research helps in understanding the overall groundwater regime and distribution by providing data (i.e., hydraulic parameters of the aquifer and surrounding rocks, water flow velocities) on sub2024 | 77/3 | 291–310 | 9 figs. | 1 tab. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society article history: manuscript received: may 16, 2024 revised manuscript accepted: june 11, 2024 available online: august 28, 2024 keywords: thermal spring, conceptual modelling, numerical modelling, recharge area, fractured carbonates, sw pannonian basin, central croatia mailto:bojan.matos@rgn.unizg.hr g eo lo gi a c ro at ic a 292 geologia croatica 77/3 surface conditions influencing the water circulation (fetter 2001; goldscheider et al.2010; szanyi & kovács, 2010; lei & zhu, 2013; rman, 2014; fabbri et al., 2017). quantifying and monitoring the hydrogeological parameters of the thermal aquifer and water is necessary for predicting the exploitable water volumes with an acceptable drawdown and identifying detrimental effects on the system. additionally, thermal parametrisation of the geological units involved in the thermal fluid flow helps define the changes in the temperature field and fluid distribution across the system (fuchs & balling, 2016; xiong et al., 2020). the investigations mentioned above aid in the construction of a conceptual model of the studied hydrothermal system. developing the conceptual model of a hydrothermal system consolidates the existing understanding by integrating multidisciplinary and multiscale datasets. conceptual models describe the main processes governing both fluid flow and heat transport, which influence the volume of the hydrothermal resource and its geochemical and thermal characteristics. the aforementioned geological reconstructions serve as the foundation for a hydrogeological conceptual model of the hydrothermal system, elucidating the mechanisms governing hydrothermal resource formation (moeck et al., 2014; calcagno et al., 2014, mroczek et al., 2016). the physical reliability of the conceptual model can be constrained by developing variable-density fluid flow and heat transport numerical simulations of the system. numerical models can be used for testing and quantifying the importance of different processes in the development of the geothermal resource and its physicochemical characteristics (e.g., mádl-szőnyi & tóth, 2015; havril et al., 2016; montanari et al., 2017 bo rović et al., 2019; pola et al., 2020; torresan et al., 2022). furthermore, they can be used to reconstruct the historical and current state of the system and to forecast future impacts (anderson et al., 2015). thermal springs in croatia are generally part of intermediate-scale hydrothermal systems, including recharge areas in the nearby mountainous hinterlands and geothermal aquifers mainly hosted in mesozoic carbonate rocks (goldscheider et al., 2010; borović et al., 2016). their occurrence is favoured by the regional thermal characteristics in central and northern croatia that are part of the pannonian basin system (pbs). the tectonic setting of the pbs is characterised by the thinned lithosphere, which enables an above-average heat flow from the asthenosphere (horváth et al., 2015). in the pbs, three levels of the regional flow of thermal water have been identified: i) gravity flows in the neogene-quaternary clastic rocks and sediments of the basin fill (the shallowest), ii) gravity flows in pre-neogene confined carbonate aquifers below them, and iii) flow caused by overpressure in the deepest mesozoic aquifers (horváth et al., 2015; vass et al., 2018). the mesozoic carbonate rocks, representing the deepest geothermal aquifers, usually crop out either as inselbergs or along the margins of the basin. this could imply the occurrence of greater recharge in the marginal parts of the pbs, where the aquifer is shallower and covered by thinner neogene deposits, favouring the development of local to intermediate scale hydrothermal systems (stevanović, 2015; havril et al., 2016). the artesian thermal springs of topusko have been renowned since roman times, ranking as the second warmest in croatia (borović et al., 2016; šimunić, 2008). thermal water with temperatures of up to 65°c has been used since the 1980s for health and recreational purposes and district heating. despite this fact, the geological features driving the development of the topusko hydrothermal system (ths) and regulating the regional groundwater flow direction remained uncertain. in the initial stages of ths research, the potential recharge area was determined by defining outcrops of permeable rocks in topographically prominent areas. the lack of previous systematic and detailed structural-geological and hydrogeological investigations hindered the reconstruction of the regional geological evolution and understanding of how the ths functions. though available publications and unpublished reports suggest contradictory hypotheses, the most commonly used conceptual model is from the early 2000s (šimunić, 2008). in this study, we propose a novel conceptual model of the ths, detailing the recharge area and main circulation paths using a collection of structural, geochemical, and hydrogeological field data. the second objective of this research involves conducting 2d numerical modelling to analyse fluid flow and heat transport within the ths. here, the 2d numerical modelling served as a physical validation for the proposed conceptual model, supporting it with the quantification of the main processes governing the development of the topusko geothermal resource. 2. materials and methods 2.1. tectonic setting the ths formed in the pre-neogene basement units of the internal dinarides (fig. 1). the internal dinarides, as an integral part of the adria microplate, convey adria’s eastern passive margin that was involved in a complex tectonic collision between the adria microplate and european foreland during the cretaceous-paleogene period (schmid et al., 2020 with references). this tectonic contraction (the recent convergence rate between the adria indenter and europe is ≤ 4.17 mm/yr according to d’agostino et al. 2008) resulted in the formation of a dinaridic orogen system, tectonic suture zone (i.e., sava suture zone), and 400 km eastward extrusion of the alcapa block (i.e., eastern alps, west carpathians and transdanubian ranges; tari et al., 1999; csontos & vörös, 2004). besides the formation of an orogen-parallel thrust fault system, tectonic contraction accommodated the formation of regional dextral/sinistral faults (e.g., the splitkarlovac fault, periadriatic fault that extends into the midhungarian fault zone further to the e; fig. 1), which enabled ccw/cw rotation and partial tectonic exhumation of the nearby tectonic blocks of the adria microplate and the tiszadacia mega-unit (e.g. tomljenović, 2002; tomlje nović et al., 2008; ustaszewski et al., 2010; schmid et al., 2020). at the same time, as the study area is positioned in the immediate vicinity of the transient zone between the adria g eologia c roatica 293pavić et al.: a conceptual and numerical model of fluid flow and heat transport in the topusko hydrothermal system microplate (w) and the tisza mega-unit (e), the inherited fault system is characterised by polyphase tectonic evolution and persistent structural reactivation of the faults (fig. 2; schmid et al., 2008). as a result, the ths bedrock units (fig. 3) resemble a complex lithostratigraphic mosaic of palaeozoictriassic clastic and carbonate units, that are often seen in tectonic contact with younger jurassic-cretaceous ophiolitic mélange units (schmid et al., 2008), and its paleogeneneogene cover. the neogene-quaternary tectonic evolution of the study area, on the other hand, was further affected by back-arc type formation of the pbs (royden & horváth, 1988; horváth et al., 2006; cloetingh at al., 2006). formation of the pbs was characterised by repeated early-middle miocene e-w oriented lithospheric extension (c. 26-11.5 ma), along the nnw-striking normal listric faults (i.e., the sava fault; fig. 2), which was followed by its late miocene -pliocene-quaternary tectonic inversion due to n – s compression (e.g., prelogović et al., 1998; tari et al., 1999; tomljenović & csontos, 2001; cloetingh et al. 2006; schmid et al., 2008; brückl et al., 2010). in the croatian part of the pbs, a neogene-quaternary sediment succession (fig. 3) is associated with the dominant nnw-striking sava, karlovac and glina basins and subbasins, which were tectonically inverted and highly deformed during the late miocene-pliocene-quaternary periods (pavelić, 2001; pavelić et al., 2003; tomljenović & csontos, 2001). tectonic deformation of the neogene-quaternary figure 1. regional tectonostratigraphic units that surround the study area of the ths (red dashed polygon corresponds to the extent of fig. 3). map shows the main regional fault systems that accommodated the tectonic collision of the adria microplate and european foreland during cretaceouspaleogene time. the study area is located at the eastern margin of the adria microplate, within the internal dinarides, close to the sava suture zone (modified after schmid et al., 2008; 2020). g eo lo gi a c ro at ic a 294 geologia croatica 77/3 succession in the study area is especially pronounced along the contact with the palaeozoic-triassic anticlinal core of the petrova gora mt. (horváth & tari 1999; tomljenović & csontos, 2001). though tectonic uplift of the petrova gora mt. had probably already started during the cretaceous-paleogene contraction (similar to the other pbs pre-neogene basement highs e.g., trgovska gora, slavonian mts.), the final uplift commenced during the late miocene-pliocene-quaternary compression/transpression phase that resulted in tectonic exhumation, tectonic overprint of its palaeozoic-mesozoic structures, and formation of kilometre-scale folds along the reactivated and newly formed faults in the area (fig. 2; prelogović et al., 1998; tomljenović & csontos, 2001). ongoing, local nne-ssw regional compression in the study area is driven by residual adria indentation shortening locally at the scale of 1-2 mm/yr and is accommodated along the inherited faults with slip rates below 0.1 mm/yr (grenerczy et al., 2005; kastelic & carafa, 2012; ustaszewski et al., 2014). 2.2. geological setting a composite geological map covering the study area (fig. 3) was constructed using basic geological maps of the former yugoslavia at a scale of 1:100.000, sheets karlovac (benček et al., 2014), sisak (pikija, 1987), slunj (korolija et al., 1980), and bosanski novi (šikić, 1990), as well as the 1:500.000 scale geological map (federal geological survey, 1970). a description of the subsurface geological composition was compiled, including a composite geological column that outlines the lithostratigraphic and chrono stratigraphic sequence of deposits in the area. the synthesis of existing data was undertaken using gis and graphical editing tools. the geological setting of the study area predominantly comprises late palaeozoic, triassic, and plio-quaternary to quaternary deposits, which cover older variscan bedrock and structures. in the se part, carboniferous deposits (c) are the oldest exposed rocks (fig. 3). they are predominantly composed of clastic and subordinately carbonate deposits, includfigure 2. the structural map shows a simplified tectonic framework of the fault systems at the sw margin of the pbs. fault abbreviations: sf – sava fault; pfpokupsko fault; gf – glina fault. fault systems are compiled after korolija et al. (1980), velić & sokač (1982), bukovac et al. (1984), pikija (1987), šikić (1990), prelogović et al. (1998), tomljenović & csontos (2001), benček et al. (2014), and herak & herak (2023). g eologia c roatica 295pavić et al.: a conceptual and numerical model of fluid flow and heat transport in the topusko hydrothermal system ing shales, siltites, sandstones (greywacke, quartz-greywacke), and dolomitised and ankeritised limestones. together with the devonian deposits (d), characterised by thick lenses of clay, limonitised and schisty limestones within interbeds of shales, siltstone and sandstones form the pre-permian low-grade meta morphic basement (šikić, 1990). continuation of the post-carboniferous deposition sequence is characterised by a clastic sequence of younger palaeozoic age and is found on the southern slopes of petrova gora mt. (fig. 3). permian deposits (p) are represented by schists, quartz-greywacke sandstones, shales, and fine-grained conglomerates (korolija et al., 1980). this turbidite-like complex was developed under conditions of rapid and constant infilling within the existing basement basinal structures, reaching thicknesses of 500 m. at the same time, permo-triassic deposits (p, t) are consistent and composed of finegrained brick-red sandstones and sandy-clay shales (korolija et al., 1981). the quartz-rich greywackes of the upper permian, observed along the southern slopes of the petrova gora mt., are a marker that represents transitional strata from the upper permian to the lower triassic (fig. 3), which were deposited in shallower marine environments due to orogenic uplift. lower triassic (t1) deposition of mica sandstones, siltites, and shales with a gradual transition to carbonate marls and eventually limestones and dolomites continuously followed the upper palaeozoic normal superposition (korolija, 1981). these deposits can be observed on the eastern slopes of petrova gora mt., concordantly overlapping older permian deposits (fig. 3). during the middle triassic (t2), evidence of consistent limestone and dolomite deposition can be observed. at the local scale, within the carbonate facies, tuffs, finegrained sandstones, and interlayers of sheet limestone with chert alongside the shales were observed. the diminishing presence of clastic and pyroclastic components within the uppermost middle triassic succession suggests a reduction in tectonic activity and volcanism. during the late triassic period (t3), stable marine conditions enabled further massive figure 3. geological map of the study area of the ths according to the basic geological maps of the sfry at a scale of 1:100.000, sheets karlovac (benček et al., 2014), sisak (pikija, 1987), slunj (korolija et al., 1980), bosanski novi (šikić, 1988) and geological maps of sfr yugoslavia, scale 1:500.000 (federal geological survey, 1970). acronyms of the lithostratigraphic units: q – quaternary; pl, pl,q – pliocene, plio – quaternary; m miocene; pc,e-ol – paleocene and eocene-oligocene; k, pc – cretaceous-paleogene k – cretaceous; j jurassic; t triassic; p,t – permian triassic; p – permian; c – carboniferous; d – devonian. thermal springs’ locations in bosnia and herzegovina after hrvatović (2005). the extent of the study area is shown in figure 1. g eo lo gi a c ro at ic a 296 geologia croatica 77/3 carbonate deposition in the area. the upper triassic dolomites (w of hrvatsko žarište, fig. 3) are usually in tectonic contact with the lower – upper cretaceous limestones. according to schmid et al. (2008), late jurassic regional movements prompted the intraoceanic subduction of the neotethys oceanic realm, which coexisted with the fragmentation of the adria microplate. this led to the adria microplate terrain differentiation, which resulted in variable sedimentation patterns and continuous jurassic-cretaceous carbonate sedimentation in the area of the adriatic carbonate platform (vlahović et al., 2005), while clastic-carbonatevolcanic sedimentation prevailed along its passive margins. the jurassic rock complex in the study area (j2,3), part of this passive margin, primarily comprises a magmatic-sedimentary ophiolitic complex within the central dinaridic ophiolitic zone (schmid et al., 2008). this approximately 800 m thick complex consists of low-metamorphosed sedimentary rocks, (i.e., sandstones, shales, cherts, and some siltites, marly shales, and fine-grained limestones) and various magmatic rocks (i.e., basalts, gabbros, diabases; korolija et al., 1981; šikić, 1990). the cretaceous-paleogene transgressive sequence (fig. 3) indicates passive margin sedimentation (korolija et al., 1981). cretaceous deposits (k1) include limestones, greenishgray marls, silicified sandstones, and carbonate breccias, followed by a flysch-turbidite like succession (k1,2) (vlahović et al., 2005). paleogene deposits are mainly flysch-like, with carbonate marls, marly limestones, and thin layers of shales, marls, and fine-grained sandstones (k, pc). palaeocene and eocene-oligocene flysch-like deposits (pc, e-ol) crop out to a small extent in the eastern part of the study area. the neogene-quaternary sediment succession, linked to the tectonic evolution of the croatian part of the pbs, was deposited in half-graben structures formed during the early-middle miocene (prelogović et al., 1998; tomljenović & csontos, 2001; saftić et al., 2003). extensional tectonics led to basins filled with marine, lacustrine, and freshwater sediments (pavelić et al., 2003). this succession, about 1.1 km thick, includes conglomerates, sandstones, gravels, clays, marls, and limestones (m; pl, q; fig. 3) (šikić, 1990). the youngest pliocene and quaternary deposits (pl; q), approximately 200 m thick, consist of conglomerates, sandstones, siltstones, sands, gravels, clays, and occasional interlayers of clay and coal, forming a final terrigenous/alluvial cover. 2.3. hydrogeological setting in the topusko area, there are three natural artesian thermal springs with a total capacity of approx. 25 l/s (bać & herak, 1962; bahun & raljević, 1969) and temperatures ranging from 46 °c to 53 °c. three exploitation wells were drilled to depths of up to 250 m in the immediate vicinity of the natural springs during the 1980s. they are currently used for heating, recreational, and medicinal purposes, with a total yield of 200 l/s and pressure of around 1.4 bar (pavić et al., 2023). a decrease in pressure from 2.18 bar (1978) to 1.52 bar (1982) was observed and attributed to overexploitation (šegotić & šmit, 2007). the topusko thermal water shows a slightly acidic character, with an average ph of 6.5 – 6.8. the electrical conductivity ranges from 582 μs/cm to 680 μs/cm, and the total dissolved solids are approx. 500 mg/l indicating a medium to low mineralised fresh water. hydrochemical analyses show a ca-hco3 hydrochemical facies (pavić et al., 2023, 2024) indicating water flow in carbonate rocks. stable water isotopes δ2h and δ18o suggest a meteoric origin for thermal water and recharge during colder climatic conditions the uniform δ18o values indicate deep circulation and a large, thick aquifer, which homogenises seasonal precipitation variations over longer residence times. the estimated mean residence time of approximately 8.5 – 9.5 kyr is based on 14c content in dic (pavić et al., 2024). tritium activity in the thermal water is generally below the detection limit, but trace levels were detected after extensive abstraction for district heating during winter months, suggesting the potential infiltration of modern precipitation through the semipermeable neogene cover sequence of the aquifer. the most plausible equilibrium aquifer temperature was estimated at 90 °c using quartz geothermometers (pavić et al., 2023, 2024). hydrodynamic measurements in the topusko discharge area estimated an aquifer transmissivity of approx. 2 x 10-2 m2/s (pavić et al., 2023). according to šimunić (2008), a set of faults forming a block in the shape of a three-sided prism enabled the uplifting of the aquifer. the result of an electrical resistivity survey identified the damaged zones of these faults in the spring area (pavić et al., 2023). from a hydrogeological point of view, fractured and karstified, highly permeable, middle and upper triassic carbonates are the main geothermal aquifer of the ths. lower triassic and permian-triassic carbonate and clastic rocks represent the semi-confining units at the base of the reservoir, while the palaeozoic complex is the impervious basement at the bottom of the stratigraphic sequence due to its low-grade metamorphism. furthermore, low permeability jurassic ophiolitic complex and neogene-quaternary deposits cover the geothermal aquifer. however, a limited number of deep boreholes hinders a more comprehensive understanding of local and regional scale hydrogeological conditions. different conceptual models of the ths have been previously proposed: 1) in the early 20th century, it was considered that the thermal water at the topusko springs was heated by a magmatic body based on the existence of basalt outcrops in the vicinity (e.g., lasinja gorjanović-kramberger, 1905, 1917). to support the volcanic origin of the thermal water in topusko, gorjanović-kramberger (1917) postulated that mountains s of topusko could not produce such hydrostatic pressure that would raise water from a depth of approx. 1.5 km, according to the thermal water temperature at the surface. however, these basalts are of mesozoic age (majer, 1978; 1993) and quaternary magmatic bodies behaving as a recent heat source for hydrothermal systems are absent within the pbs. therefore, this conceptual model was abandoned. 2) bać & herak (1962) interpreted the palaeozoic rocks as behaving as an impermeable rock complex that regulates regional water circulation and defines the watershed of the ths together with lower triassic and neogene formations. according to the same authors, permeable middle g eologia c roatica 297pavić et al.: a conceptual and numerical model of fluid flow and heat transport in the topusko hydrothermal system and upper triassic carbonate deposits facilitate deep groundwater circulation, especially in tectonically active areas. the thermal aquifer receives recharge in the glina river headwaters, where triassic carbonates crop out. the proposed primary regional flow direction is from the s to n, from the glina area towards the topusko depression. 3) šimunić (2008) proposed that the ths recharge area is located w of the petrova gora mt., where triassic carbonates crop out. according to the proposed model, the water circulates from w to e below the petrova gora nappe, heats up by the geothermal gradient, and discharges in topusko due to the highly permeable fault damaged zones. 2.4. structural-geological research structural-geological fieldwork was conducted through field campaigns in 2021 and 2022. field investigations involved structural and lithological data acquisition at 162 locations covering an area of approx. 2,000 km2 (figs. 2 and 3). during the fieldwork, observation points were archived and processed in the avenza pdf maps application (url 1) and ms excel field database, while database creation and geospatial positioning of the collected geological data were performed using the software arcmap 10.1 (url 2). the structural investigations detailed the stratigraphic relationships among the main lithological units and the analysis of the tectonic and structural settings in the study area. they encompassed geometric and structural measurements of strata bedding, fractures/joint systems, and fault/shear planes. in particular, measurements of fault/shear planes included the identification of fault kinematic indicators and determination of the tectonic relationships between the observed structures. collected structural data were used in the construction of three ne-sw striking regional structural-geological profiles (ths-1 to ths-3; figs. 2–4). these profiles represent surface/subsurface 2d models of the distribution of geological units and structures in the area of petrova gora mt. (sw) and the glina depression (ne) and they were used here for recon struc tion of the geological and structural settings of the ths. 2.5. conceptual and numerical modelling in this study, we initially tested and compared the validity of the conceptual model proposed by šimunić (2008) with the results of structural investigations and the constructed geological profiles. furthermore, these data combined with the results of previous investigations in the topusko area were used to update the conceptual model of the ths, which served as a base for a 2d numerical model of heat flow and fluid transport. the conceptual model was developed including: lithological field data, geological maps, hydrodynamic and electrical resistivity survey data acquired in the discharge area of topusko, chemical and isotopic compositions of both the thermal water and the precipitation in the assumed recharge area. the proposed conceptual model was tested by performing numerical simulations of f luid f low and heat transport accounting for the variation of the thermal water density due to the temperature distribution in the subsurface (bundschuh & césar suárez, 2010; diersch, 2014). the numerical model solves the governing equations of fluid flow and heat transport, obtaining the distribution of the primary variables (i.e., hydraulic head and temperature) within the modelling domain and over time. in this research, we used the feflow 7.4 software (diersch, 2014), a finite elementbased simulator specifically designed to address fluid flow and transport phenomena within porous and fractured media. the fundamental equations governing fluid flow and heat transport in these media are formulated based on conservation principles for fluid mass, momentum, and thermal energy (diersch, 2014). the equations are coupled by setting a functional form behaviour for fluid density and viscosity depending on the respective primary variable of the problem. for the specific problem at hand, fluid viscosity was kept constant. in contrast, the density of the fluid varies linearly with temperature, following r = r0 (1 – adt) with a being the volumetric thermal expansion coefficient of the fluid (pola et al., 2020). 3. results 3.1. structural-geological profiles structural – geological profiles ths-1 to ths-3 (fig. 4) represent an interpretation of the surface/subsurface relationships in the study area down to an investigation depth of approx. 6 km. constructed geological profiles include three structural domains that convey a system of thrust faults separating the external dinaridic lithological units in the sw parts of the profiles from the internal dinaridic lithological units. the internal dinaridic units can be further subdivided into two subdomains. the se and central part of the profiles included the petrova gora area, while the glina depression characterises the ne profile domains (fig. 4). the profiles (figs. 2 and 4) pinpoint complex faulted and folded structures that are predominantly affected by low angle thrust faults (dip angle ≤30°; faults r1, r2, and r3 in fig. 4) and reverse faults in their immediate hanging wall (faults r5 and r2 in fig. 4). besides these faults, higher angle normal and tectonically inverted normal faults are observed (dip angle ≥45°; faults r4 and r6 in fig. 4). constructed profiles show that the ths subsurface is composed of folded structures, with the largest topusko anticline formed in the hanging wall of the r3 thrust fault and r5 blind fault (profile ths-3 in fig. 4). the petrova gora structure also resembles a larger-scale anticlinal structure that is tectonically uplifted in the hanging walls of the r1 and r2 thrust faults (profile ths-1 in fig. 4). the petrova gora structure, composed of a palaeozoic clastic sequence, is tectonically uplifted by approx. 3.5 km in relation to its r1 footwall units, which resemble an undeformed, 6 km thick, palaeozoic-mesozoic succession. towards the ne, the petrova gora structure is additionally vertically displaced by tectonically inverted normal faults (faults r3 and r4; profile ths-1 in fig. 4). here, vertical displacement along the r3 and r4 normal faults accommodates ne-sw oriented extension, with approx. 1.5 – 2 km vertical subsidence. further to the ne, the r4 fault delineates a folded system that incorporates the area of the topusko anticline. with an approx. 4 km thick palaeozoic-mesozoic succession, this folded system (profile ths-3 in fig. 4) is mainly composed of the carboniferous-permian clastic succession that is covered g eo lo gi a c ro at ic a 298 geologia croatica 77/3 by triassic clastic-carbonate rocks. the topusko anticline hinge zone is partly covered by the jurassic ophiolitic complex and its transgressive cretaceous clastic-carbonate succession (see figs. 3 and 4, profile ths-3). in the area of the topusko anticline, both the cretaceous and jurassic units are significantly reduced due to extensive uplift along the r5 blind figure 4. structural-geological profiles in the ths area. the ne-sw striking profiles are perpendicular to the geological structures in the research area. the profiles show the topusko anticline formed in the hanging wall of the thrust fault r3 that behaves as a low-angle detachment surface. the anticline is composed of a thick palaeozoic-mesozoic sequence, which is partly eroded in the immediate area of topusko town. towards the ne, it is covered by the thick paleogene-neogene sedimentary succession of the glina depression. horizontal and vertical scale ratio is 1:1. g eologia c roatica 299pavić et al.: a conceptual and numerical model of fluid flow and heat transport in the topusko hydrothermal system fault, which resulted in hanging wall tectonic erosion. the final ne domains of the ths geological profiles incorporate the gently dipping ne limb of the topusko anticline that is faulted by the ne dipping r6 normal fault. the r6 normal fault (vertical displacement here is approx. 500 m; profile ths-3 in fig. 4) is part of the extensional structure of the glina depression, which is one of the extensional basins formed during the neogene extension of the croatian part of the pbs. as a result, the ne segments of the ths profiles are covered by an additional approx. 2 km thick clastic-carbonate succession deposited during the paleogene and neogene within the glina depression. reconstructed ths subsurface relationships along the profiles indicate that the observed faults and cogenetic folded structures have a history of polyphase deformation. the same asymmetric anticlinal structures (e.g., petrova gora) in the hanging wall of the low angle detachment faults (e.g., r3 and r4 faults, fig. 4) show indications of tectonic transport towards the sw, localised uplift and erosion (e.g., topusko anticline), as well as ne – sw oriented extension. this implies that the interpreted faults accommodated both initial cretaceouspaleogene ne – sw compression and the following neogene ne – sw extension. 3.2. conceptual and numerical modelling of groundwater flow and heat transport in the ths 3.2.1. novel conceptual model of the ths the new conceptual model of the ths is established based on constructed geological profiles (fig. 4) and previous hydrogeological and geophysical research (pavić et al., 2023, 2024). these data lead to development of an interpolated schematic geological profile, which refines the understanding of the ths (figs. 5 & 6). analysis of the geological profiles figure. 5 trace of the interpolated schematic geological profile of the ths (black line). sinkholes (white circles) in the sw part of the profile indicate higher karstification of the carbonate formations, representing the potential recharge area of the ths. g eo lo gi a c ro at ic a 300 geologia croatica 77/3 here, challenges the previously proposed hypothesis by šimunić (2008) about the recharge area of the ths being w of the petrova gora nappe. the triassic carbonates cropping out w of the petrova gora mt. are hydrogeologically isolated from the discharge area in topusko by the impermeable petrova gora structure, which is composed of a palaeozoic clastic sequence with low-grade metamorphism. therefore, a regional groundwater flow from w to e becomes highly unlikely. instead, in our conceptual model, attention is directed towards a new hypothesis: the recharge occurs s from topusko, where triassic carbonates are partly exposed at the surface. the surface manifestation of thermal water in the topusko spring area can be understood through the concept of gravitydriven groundwater flow, determined by: i) middle-upper triassic carbonate complex rocks, which are the main thermal aquifer of the ths, ii) palaeozoic-lower triassic and the jurassic-neogene formations representing the semi-confining layers at the bottom and top of the reservoir, respectively, iii) a large area characterised by intense karstification occuring approx. 13 km s of topusko within the triassic carbonates (fig. 5), facilitating the infiltration and deep circulation of the meteoric water with a long residence time, and iv) the faultthrusted regional tectonic setting and the existence of substantial hydraulic boundaries (e.g., the r3 and r4 thrust faults and near-surface fault zones), which influence the direction of the groundwater flow. the topusko anticline within the hanging wall of the r3 thrust fault facilitates the uplift of the aquifer, bringing it closer to the surface in the thermal springs area. cogenetic faults and fracture networks in the hinge zone of the topusko anticline, probably affected by an extensional regime, increase the fracturing of the bedrock and the permeability field in the aquifer enabling the thermal water outflow. the occurrence of fault damage zones in the topusko subsurface was determined by the electrical resistivity surveys (pavić et al., 2023). hydrogeochemical research corroborates the meteoric origin of the topusko thermal water and the interaction with the carbonate aquifer. a residence time of approx. 9 kyr is evidenced by the 14c analysis of the thermal water (pavić et al., 2024). additionally, the consistent major ion composition of the thermal water over a two-year period suggests a large and stable system. based on all findings, it is suggested that the novel ths conceptual model favours a regional groundwater flow direction from s to n. 3.2.2. setup of the numerical model the physical validity of the proposed conceptual model of the ths was tested by conducting 2d numerical modelling of both the regional fluid flow and heat transport. to simulate gravity-driven groundwater flow in the ths, we adopted a shortened version of the schematic geological profile (fig. 6), excluding the sw portion of the r3 fault. the recharge area of the ths is located ne of r3, where numerous sinkholes occur (fig. 5). therefore, the sw portion of the section is not strictly connected to the hydrothermal system, and was not reproduced in the numerical model to diminish the computational effort for solving the numerical simulations. the profile was digitised in gis software and used to generate a sufigure 6. interpolated geological profile of the ths. the profile is perpendicular to the topusko anticline formed in the hanging wall of the thrust fault r3 that behaves as a low angle detachment surface. the same fault, combined with the r4 and r5 reverse faults, lifts the reservoir up to shallow depths in the immediate area of topusko town. horizontal and vertical scale is 1:1. g eologia c roatica 301pavić et al.: a conceptual and numerical model of fluid flow and heat transport in the topusko hydrothermal system permesh in the feflow software outlining the geometry of the geological units within the modelling domain. the domain was discretised through a triangular mesh employing the triangle triangulation code (diersch, 2014), which permits honouring the complex geometrical relationships of the units. the mesh was refined in the hinge zone of the topusko anticline, in the aquifer unit, and along the main faults. such refinement allows a better discretisation in the parts of the model where numerical instability is expected. the obtained mesh (fig. 7) comprised 19,241 triangular elements and 9,831 nodes. geological units with similar hydrogeological and thermal properties were grouped, obtaining seven hydrostratigraphic units: i) palaeozoic low-metamorphic sedimentary complex (b), ii) permian and permian-triassic clastic units (p), iii) early triassic sedimentary rocks (t1), iv) middle and late triassic carbonates (t2,3), v) jurassic magmatic – sedimentary ophiolitic complex and jurassic and cretaceous carbonates (j), vi) neogene siliciclastic units (n), and vii) quaternary alluvial cover (q). in particular, the t2,3 hydrostratigraphic unit represents the main thermal aquifer of the ths. the equivalent porous medium approach was employed for the hydrogeological and thermal parametrisations of the hydrostratigraphic units (diersch, 2014; anderson et al., 2015). this approach considers the unit as a porous medium with homogeneous and isotropic properties being suitable for the numerical modelling of regional groundwater flow systems in heavily fractured and karstified carbonate rocks (teutsch & sauter, 1991; scanlon et al., 2003; ghasemizadeh et al., 2012; mádl-szőnyi & tóth, 2015). in a regional numerical model, the scale of these discontinuities is smaller than the representative elementary volume (i.e., the mesh size), resulting in a constant and homogeneous value of the considered parameter. for assigning the hydraulic and thermal properties (table 1), we considered the main lithology of the hydrostratigraphic units and relied on data from the literature (cermak & rybach, 1982; domenico & schwartz, 1997; fetter, 2001; stylianou et al., 2016; borović et al., 2018; stober & bucher, 2021; laloui & rotta loria, 2020), parametrisation of similar units in hydrothermal systems within the pbs (rman & tóth, 2011; mádlszőnyi & tóth, 2015; havril et al., 2016), and datasets obtained from field investigations in topusko (pavić et al., 2023). the hydraulic conductivity (k) and the porosity (φ) were assigned accounting for the role of the units in the ths. excluding the loose sediments of the quaternary cover (q unit; fig. 3), the highest k and φ values were assigned to the t2,3 hydrostratigraphic unit representing the thermal aquifer. conversely, the impervious basement b was reproduced using the lowest k and φ values. in the hinge zone of the topusko anticline, k and φ were increased simulating the impact of the local scale fracturing that favours the upwelling of the thermal water. open fractures can increase the permeability and porosity fields enhancing the fluid flow in the aquifer (i.e., faulkner et al., 2010; worthington et al., 2019; pouraskarparast et al., 2024). the regional values of k and φ were increased by: i) two orders of magnitude and 10%, respectively, for the t2,3, t1, and p units, and ii) one order of magnitude and 5%, respectively, for the b unit considering the decrease of fracture apertures with depth. in particular, the k value of the t2,3 unit in the hinge zone of the topusko anticline was calculated from a collection of transmissivity values obtained from well tests conducted in topusko (pavić et al., 2023). furthermore, the thermal conductivities (λ) of the n and t2,3 units were derived from rman & tóth (2011), mádl-szőnyi & tóth (2015), and havril et al. (2016), who investigated regional groundwater flow and heat transport patterns in the pbs. boundary conditions (bcs) for fluid flow and heat transport were applied at the border of the modelling domain following the conceptual model of the ths. the fluid flow bcs (fig. 7a) included: i) a 2nd kind (neumann) bc at the sw part of the top domain, and ii) a 3rd kind (cauchy) bc at the top of the domain in the topusko area. the neumann bc produces an inflow in the modelling domain and was employed to simulate the recharge of the ths. the condition spanned for a length of 2 km, which corresponds to the extension of the area with a higher density of sinkholes along the modelling domain. an inflow of 90 mm/yr was imposed considering an effective infiltration of 10 % (as being used for the simulation of similar hydrothermal systems in a carbonate reservoir in croatia; borović et al., 2019) and an average annual precipitation of 900 mm (dhmz, 2021; martinsen et al., 2022). the cauchy bc simulates a fluid flux through the model boundary depending on: i) the difference between the hydraulic head imposed at the boundary and the value calculated within the domain, and ii) a transfer-rate coefficient (diersch, 2014). since it is generally used to simulate the variable outflow in springs (anderson et al., 2015), it was employed in the ths numerical model to reproduce the occurrence of thermal springs in the topusko area. the imposed hydraulic head was set as the average ground elevation (122 masl), while the transfer rate was calculated as the k of the q unit (table 1) divided by the thickness of the alluvial cover in topusko obtained from the stratigraphic well logs. the heat transport bcs (fig. 7b) included: i) a 1st kind (dirichlet) bc at the sw and ne vertical boundaries of the modelling domain and at the top except for the topusko area, ii) a 2nd kind (neumann) bc at the bottom, and iii) a 3rd kind (cauchy) bc at the top of the domain in the topusko area. the dirichlet bc imposes a constant value of the primary variable. in the ths model, it was used to reproduce both the ground temperature at the surface and the increasing temperature with depth due to the regional geothermal gradient at the vertical boundaries. the temperature imposed at the top was set to 10 °c, which corresponds to the mean average annual air temperature, while the values at the lateral boundary were obtained from the initial distribution of temperature. the neumann bc was used to simulate the regional inflow of heat from the deeper parts of the crust. a value of 100 mw/m2 was imposed being consistent with the average heat flow in the croatian part of the pbs (lenkey et al., 2002; horváth et al., 2015). similarly to the fluid flow, the cauchy bc reproduces a heat flux through the boundary depending on: i) the difference between the reference and the calculated temperature values, and ii) a transfer-rate coefficient (diersch, 2014). the reference temperature was set to 10 °c following the value imposed for the dirichlet bc, while the transfer rate was calculated as the λ of the q unit (table 1) divided by its thickness. g eo lo gi a c ro at ic a 302 geologia croatica 77/3 the ths numerical modelling was conducted performing transient state numerical simulations that account for the variations of the hydraulic head and temperature distributions over time. therefore, it is important to set appropriate initial conditions for these variables achieving a better convergence of the numerical solution at the initial stages of the simulation. the initial value of the hydraulic head was set as 122 m, corresponding to the hydraulic head imposed at the fluid flow cauchy bc. the initial distribution of the temperature was obtained through a steady-state simulation using: i) the described set of hydrogeological and thermal parameters for the hydrostratigraphic units (table 1), ii) a 1st kind (dirichlet) bc with a constant temperature value of 10 °c at the top of the domain, and iii) a 2nd kind (neumann) bc at the bottom with imposed inflow of 100 mw/m2. the resulting temperature distribution reproduces a regional geothermal gradient of 35.8 °c/km, being consistent with available regional values in the study area (30 – 40 °c/km; macenić et al., 2020). 3.2.3. simulation results the best simulation of the ths was conducted employing the described set of hydrogeological and thermal parameters for the hydrostratigraphic units (table 1) and the imposed boundary and initial conditions (fig. 7). the transient simulation was run for 100 kyr obtaining a quasi-stationary distribution of the primary variables. this condition reproduces the long-term natural state of the hydrothermal system (i.e., garg et al., 2007; kaiser et al., 2013; havril et al., 2016; figure 7. fluid flow (a) and heat transport (b) boundary conditions (bcs) in the ths numerical model. blue circles – 1st kind (dirichlet) bc; red crosses – 2nd kind (neumann) bc; green circles with crosses – 3rd kind (cauchy) bc. horizontal and vertical scale ratio is 1:1. table 1. hydrogeological and thermal parameters assigned to the hydrostratigraphic units in the ths numerical model. unit age lithology thick k ss j l rc [m] [m s-1] [m-1] [%] [w m-1 k-1] [mj m-3 k-1] q quaternary gravel, sand, silt 90 1*10-4 1*10-4 20 1.6 1.3 n neogene sand, clay, silt, marls < 2,000 2*10-7 1*10-4 5 1.8 1.6 j jurassic magmatic-sedimentary ophiolitic complex 750 – 1,600 2*10-10 3.3*10-7 5 2 2.2 t2,3 middle-upper triassic limestone, dolostone 400 – 1,200 2*10-6 3.3*10-7 10 2.5 2.52 t1 lower triassic sandstone, marl, limestone, dolomite 600 2*10-9 3.3*10-7 5 2 1.6 p permian-triassic siliciclastic rocks 650 2*10-11 3.3*10-7 5 3 2.1 b palaeozoic schists shales, sandstones, conglomerates with limestone and dolomite lenses 2,000 – 3,000 2*10-12 3.3*10-7 2 3.5 2.1 note: k: hydraulic conductivity (domenico & schwartz, 1997; fetter, 2001; pavić et al., 2023); φ: porosity (domenico & schwartz, 1997); λ: thermal conductivity (cermak & rybach, 1982, rman & tóth (2011), mádl-szőnyi & tóth (2015), stylianou et al., 2016, borović et al., 2018; stober & bucher, 2021); ss: specific storativity (domenico & schwartz, 1997); ρc: volumetric heat capacity (laloui & rotta loria, 2020) g eologia c roatica 303pavić et al.: a conceptual and numerical model of fluid flow and heat transport in the topusko hydrothermal system borović et al., 2019; pola et al., 2020; torresan et al., 2022), which is the goal of the ths numerical modelling. the temperature variations over time at different depths in the subsurface of topusko are represented in fig. 8a. the simulated temperature gradually increases from the initial distribution reaching maximum values between 18 and 30 kyr depending on the considered depth. the temperature at the surface peaks to 42.6 °c at 18 kyr (initial value of 10 °c; depth = 0 km in figs. 8a and 8b), while it reaches the maximum value of 77.4 °c at the same simulation time at base of the aquifer (initial value of 55.8 °c; depth = 1 km in figs. 8a and 8b). the temperature differential progressively decreases with depth, being up to 2 °c in the deeper part of the modelling domain (depth = 3.5 km). after this increasing phase, the simulated temperatures progressively decrease. the final modelled temperatures at the surface and base of the aquifer are 31.3 °c and 59.5 °c (figs. 8a and 8b), respectively, de picting a drop of 11.3 °c and 17.9 °c, respectively. the drop from the peak value decreases with the depth as well and is 3 °c in the deeper part of the modelling domain. despite these variations, a practically constant temperature distribution is observed between 80 and 100 kyr with a maximum variation of 1.4 °c at the aquifer base. this result suggests that a quasistationary state of the solution was achieved. the regional and local scale spatial distributions of temperature at the end of the simulation period (figs. 9a and 9b, respectively) were further detailed. the temperature distribution within the aquifer at both regional and local scales exhibits significant spatial variability. in particular, a decrease from the initial values up to 14 °c is observed in the recharge area of the system where the infiltration of cold waters (10 °c as imposed by the dirichlet bc for heat transport) occurs. similar behaviour is observed in the recharge area of regional, topographically-driven groundwater systems (i.e., domenico & palciauskas, 1973; anderson, 2005; an et al., 2015). however, the temperature within the aquifer (pink polygon in fig. 9) is up to 25 °c (depth of 0.7 km) as expected in shallow carbonate aquifers. the temperature in the aquifer progressively decreases eastward as depicted by the 20 °c isotherm located at a depth of approx. 1.6 km in the central part of the modelling domain. this decrease is connected to the deep circulation of the infiltrated waters in the aquifer driven by both the topographic gradient and the deepening of the strata to the sw of topusko (fig. 6). the temperature increases in the hinge zone of the topusko anticline where the upwelling of the thermal water favours the rise of the isotherms toward the surface (fig. 9b). in particular, the isotherm of 35 °c is located approx. at the top of aquifer (depth of 0.1 km), while the isotherm 50 °c approaching to the water temperature of the topusko thermal springs is located at a depth of 0.4 km. the modelled temperature is: i) up to 44 °c in the central part of the thermal anomaly at the depth investigated by the thermal wells in topusko (0.2 km), ii) between 56 and 74 °c at the base of the aquifer, and iii) between 80 and 100 °c at the base of the t1 hydrostratigraphic unit, which represents the semi-confining unit at the bottom of the aquifer (depth of approx. 1.8 km; fig. 9). the circulation of the fluid is generally directed from the recharge area of the model to the outflow area in topusko. the flow mostly occurs in the t2,3 hydrostratigraphic unit where an average darcy velocity of 0.18 m/yr (5.02×10-4 m/d) is modelled. it drops to 0.01 m/yr (2.9×10-5 m/d) in the t1 and p hydrostratigraphic units at the bottom of the aquifer, and to 3.91×10-7 m/yr (1.07×10-9 m/d) in the impervious basement (b hydrostratigraphic unit). the direction and velocity of the flow in the aquifer show different distributions from the recharge to the outf low area depending on the k value of the hydrostratigraphic unit and the thickness of the aquifer. in the recharge area, the flow is almost horizontal with an average darcy velocity of 0.27 m/yr (7.3×10-4 m/d). the velocity in the recharge area shows a high variability spanning over almost three orders of magnitude (minimum and maximum of 7.06×10-4 m/yr to 1.77 m/yr, respectively). in particular, the highest values are observed ne of the r3 fault (fig. 6), where the thickness of the aquifer decreases (fig. 9a) due to the anticline between the r3 and r4 faults. in the flow-through part of the system, the flow (average velocity of 0.17 m/yr corresponding to 4.54×10-4 m/d) is generally downward following the deepening of the aquifer to the sw of topusko and resulting in the local drop of the isotherms (as depicted by figure 8. modelled temperature variations over time (a) and final temperature distribution (b) in the topusko area. g eo lo gi a c ro at ic a 304 geologia croatica 77/3 the 20 °c isotherm; fig. 9a). the flow is generally upward in the southern limb of the topusko anticline, but with similar magnitudes of the horizontal and vertical components of the darcy velocity (average value of 0.15 m/yr corresponding to 4.16×10-4 m/d). in the topusko area, the flow is upward and with a prevalent vertical component of the darcy velocity. the average velocity value is of 0.13 m/yr (3.5×10-4 m/d), being slightly lower than the values observed in other parts of the aquifer, but the velocity field is more evenly distributed with minimum and maximum values of 1.21×10-3 and 0.28 m/yr, respectively. the darcy velocity increases up to 0.28 m/yr in the upper part of the aquifer (i.e., the depth investigated by the thermal wells in topusko) pointing to the quick rise of the thermal waters in the final part of the circulation path. the outflow modelled by the 3rd kind (cauchy) bc is 0.18 m3/yr. 4. discussion the topusko hydrothermal system area is located at the tectonic boundary between the external and internal dinarides in the vicinity of the sava suture zone (schmid et al., 2020). the palaeozoic-mesozoic terrains in the study area experienced a complex polyphase tectonic evolution through the cretaceous-paleogene and the neogene-quaternary, which resulted in tectonic overprints of both regional shortening and extension. observable regional shortening is associated with several nw-striking low-angle thrust faults and reverse faults (fig. 4) that were probably formed due to the cretaceous-paleogene adria microplate and european foreland collision (schmid et al., 2020). this regional ne – sw oriented shortening (tomljenović & csontos, 2001; schmid et al., 2008; ustaszewski et al., 2008) resulted in the tectonic uplift of the petrova gora mt. and the formation of a folded system that also incorporates the topusko anticline (fig. 6). the polyphase tectonic history is further evidenced by structural reactivations of these faults and their tectonic inversions, which is observable in the tectonically inverted normal faults r3 and r4 (fig. 4) indicating a ne – sw extension in the ths area. according to tomljenović & csontos (2001), ne – sw stretching of the inherited structures within the croatian part of the pbs occurred during the early-middle miocene due to back-arc type extension. tectonic rejuvenation of the ths area through n – s regional contraction is observable at figure 9. regional temperature distribution in the modelling domain (a) and in the hinge zone of the topusko anticline (b). a local temperature anomaly in the topusko subsurface occurs reaching values of up to 74 °c at the base of the ths carbonate aquifer (pink polygon). the horizontal and vertical scale ratio is 1:1. g eologia c roatica 305pavić et al.: a conceptual and numerical model of fluid flow and heat transport in the topusko hydrothermal system the outcrop scale, with evidence of re-folding processes and mapped reverse faults within the pliocene-quaternary clastic sequence (e.g., ustaszewski et al., 2008; herak et al., 2009; herak & herak, 2023). the interpretation of the geological profiles constructed in this study suggests that the most used ths conceptual model (šimunić, 2008) was based on an out-dated geological reconstruction. furthermore, šimunić’s model was not constructed using a series of stuctural-geoloical profiles and a detailed reconstruction of subsurface relationships, but only spatial distribution of the lithological units. these shortcomings hindered the detailed understanding of complex subsurface relationships in the topusko area. the new structuralgeological interpretation was combined with geochemical and hydrogeological data (pavić et al., 2023, 2024) to propose a novel conceptual model of the ths. this model suggests that the ths is an intermediate-scale, gravity-driven, tectonically – controlled, hydrothermal system hosted in a middle-upper triassic carbonate rock complex. the thermal water is of meteoric origin infiltrating approx. 13 km to the s of topusko, where an area with intense karstification depicted by a high density of sinkholes occurs (fig. 5). these sinkholes play a significant role in facilitating the diffuse recharge of the ths aquifer. our interpretation in general coincides with bać & herak's (1962) hypothesis, which identifies middle and upper triassic carbonate deposits as the aquifer units facilitating deep groundwater circulation. they proposed that the thermal aquifer receives recharge from the glina river headwaters, where triassic carbonates are exposed, with a primary regional flow direction from s to n, aligning with our findings regarding the recharge area s of topusko. regional folded structures favour both the deep circulation of the infiltrated water, warming due to increased heat f low of the pbs (horváth et al., 2015), and the upwelling of the thermal water in the topusko area. fault and fracture systems in the hinge zone of the topusko anticline promote the fracturing of the bedrock, the increase of the permeability field in the aquifer, and the quick rise of the thermal water from the deeper part of the reservoir. the extensional regime in the anticline hinge zone, combined with cogenetic fault and fracture systems and their permeable damage zones (pavić et al., 2023), creates a synergistic effect. this synergy enhances the overall permeability field in the discharge area, leading to the formation of abundant natural thermal springs. the physical validity of the ths model was constrained conducting variable-density numerical simulations of fluid flow and heat transport. the numerical model was populated using a set of hydrogeological and thermal parameters from both the literature and field datasets. boundary conditions were imposed at the borders of the modelling domain following the conceptual model of the ths. the best simulation was run for 100 kyr developing a local increase of the temperature distribution in the subsurface of topusko (fig. 9). in particular, the modelled temperatures were 31.3 and 44 °c at the surface and at the depth investigated by wells in topusko, respectively. despite these values are approx. 20 °c lower than the observed temperatures at the same depths, they can be considered as acceptable due to the simplifications imposed during the construction of the numerical model. the thermal aquifer was reproduced using an equivalent porous medium approach, which assigns homogeneous values of the hydrogeological properties, while localised highly permeable damage zones channelling the outflow of the thermal water were not considered. the implementation of such structures in the numerical model would increase the fluid flow promoting the local increase of the temperature. in addition, a temperature between 80 and 100 °c was modelled in the semi-confining unit at the bottom of the aquifer being comparable with the reservoir temperature of 90 °c calculated with geothermometers. as discussed for the surficial temperature, the effect of localised highly permeable fault zones was not included in the conducted numerical model. these areas could favour the raising of the isotherms in the deeper part of the reservoir resulting in the higher temperature values calculated with geothermometers. the simulated temperature distribution at the local scale reproduced the field values and was almost constant during the final 20 kyr of the simulation time (fig. 8a). this result suggested that a quasi-stationary condition reproducing the natural state of the ths was achieved for a time span that is almost twice the mean residence time of the topusko thermal water. the simulation results indicate a predominant groundwater flow pattern towards the topusko discharge area. they also highlight the significant influence of the hydraulic conductivity field on groundwater flow patterns within the system. the modelled darcy velocities ranged from 0.13 m/yr (topusko) to 0.27 m/yr (recharge area) in the aquifer and decreased within the hydrostratigraphic units below it, directly reflecting the contrasting hydraulic conductivity values of different hydrostratigraphic units. this emphasises the importance of incorporating accurate k data into groundwater flow models for reliable predictions. an outflow of 0.18 m3/yr was modelled in the topusko area, reproducing the thermal springs. historical data on the flow rate of the springs before the drilling of the wells are not available and a more detailed numerical model would be needed to reproduce the effect of exploitation of the thermal water. the localised thermal anomaly in the anticline hinge zone corroborates the structural-causative processes enhancing fluid flow and heat transfer in the topusko subsurface. therefore, the results of the numerical modelling corroborate the validity of the conceptual model of the ths. in order to constrain the processes favouring the development of the modelled temperature distribution, the rayleigh number (ra) was calculated following the procedure described in turcotte & schubert (1982). ra is a dimensionless parameter indicating the threshold for the onset of free convection occurring when it exceeds the critical value of approximately 40 (turcotte & schubert, 1982; nield & bejan, 1999; pestov, 2000; mádl-szőnyi & tóth, 2015). considering the thickness of the reservoir (approx. 1 km) and its hydrogeological and thermal parametrisations, the conditions for the development of convection cells in the ths predominantly exist in the more permeable hinge zones of the topusko anticline (ra = 5,500 – 8,600 at temperature range simulated in the aquifer). conduction is the predominant heat transfer mechanism in the rest of the ths aquifer (ra < 60). g eo lo gi a c ro at ic a 306 geologia croatica 77/3 the used modelling approach proved to be a valuable initial step for understanding regional hydrogeological systems despite its simplifications. the lack of extensive boreholes or geophysical data limits the understanding of the regional geological and hydrogeological settings. complex modelling with such limited data can lead to numerous assumptions, increasing the uncertainty of the simulations. therefore, a simple numerical approach with a detailed hydrogeological and thermal parameterisation or robust geological reconstruction is initially preferable to reduce uncertainty. in the absence of a local dataset of hydrogeological and thermal properties, the parameterisation of hydrostratigraphic units in ths was conducted considering relevant regional studies and literature collections. incorporating well-documented information from the literature enhanced the credibility and robustness of the model, facilitating a more comprehensive understanding of the hydrothermal system's dynamics. as fluid flow and heat transport are three-dimensional processes, the use of a 2d profile in the conducted ths representation is likely the most important simplification. this approach does not account for the proper local and regional characterisation of faults and related subsidiary structures, which are critical for fluid flow in fractured rocks. in the wider area of the ths, a dome-like anticline structure affects the geological and structural architecture in the subsurface, as illustrated in the presented profiles (fig. 4, profiles ths-1-3). describing this complex geological setting with the 2d model is inherently problematic, as it fails to capture the total spatial variability and structural-geological intricacies. this limitation adds to the discrepancies observed between modelled and actual temperatures and fluid flows, emphasising the need for more sophisticated modelling approaches capable of accounting for the geological complexity of the ths. the construction of a 3d model, supported by a more extensive dataset of hydrogeological, structural-geological, and thermal parameters, could improve the understanding of the thermal system dynamics. considering the 3d geological architecture will significantly enhance the accuracy and reliability of future numerical simulations. future investigations will focus on conducting a comprehensive 3d geological reconstruction of the subsurface based on detailed structural-geological and geophysical investigations that are necessary to characterise and justify the proposed local and regional structuralgeological setting of the ths. this consequently includes the reconstruction of regional and local fault meshes for a more sophisticated numerical model. 5. conclusion the presented study utilised structural-geological field investigations and numerical modelling to develop a novel conceptual model of the ths. by constructing new geological profiles and integrating them with hydrogeological and geochemical data, we were able to provide new insights into the ths dynamics proposing a novel conceptual model. the recharge area of ths lies s of topusko, where triassic carbonates crop out. regional and local scale fold and fault systems favour the deep circulation of the thermal water and the upwelling in topusko forming a valuable geothermal resource. numerical modelling corroborates the proposed con ceptual model of the ths. a local temperature anomaly was simulated in the topusko subsurface reproducing the temperature field observations. the occurrence of such a localised thermal anomaly in the hinge zone of the topusko anticline suggests an enhanced fluid flow and heat transport pointing to the impact of terrestrial heat f low and local geological structures on the system. in particular, the synergetic effect of the anticline hinge, which was determined by structural investigations, and cogenetic fault/fracture systems, which were identified by surface geophysical research, results in an enhanced permeability field in the discharge area, thereby enabling the formation of abundant natural thermal springs. this study both advances the understanding of the ths and highlights the importance of integrating field observations with numerical modelling to physically validate and refine conceptual models. this integrated approach permits a more detailed reconstruction of the hydrogeological and thermal processes driving the development of geothermal resources. these aspects are crucial for developing site-specific exploitation plans of the resource, favouring its long-term utilisation. acknowledgement this research was funded by the croatian science foundation (hrzz), grant number uip-2019-04-1218. references anderson, m.p. (2005): heat as a ground water tracer.– groundwater, 43/6, 951–968. doi: 10.1111/j.1745-6584.2005.00052.x anderson, m., woessner, w. & hunt, r. (2015): applied ground water modeling: simulation of flow and advective transport.– elsevier, london, 533 p. an, r., jiang, x.-w., wang, j.-z., wan, l., wang, x.-s. & li, h. (2015): a theoretical analysis of basin-scale groundwater temperature distribution.– hydrogeol. j., 23/2, 397–404. doi: 10.1007/s10040-014-1197-y bać, j. & herak, m. (1962): prijedlog određivanja užih i širih zaštitnih zona termomineralnih izvora u hrvatskoj [recommendation for determination of wider and narrow protection zones for thermo-mineral springs in croatia – in croatian].– unpublished report, institute for geological research, zagreb, 147 p. bahun, s. & raljević, b. (1969): mineralna, termalna i ljekovita vrela [mineral and thermal springs – in croatian].– unpublished report, institute for geological research, zagreb. békési, e., lenkey, l., limberger, j., porkoláb, k., balázs, a., bonté, d., vrijlandt, m., horváth, f., cloetingh, s. & van wees, j.d. (2018): subsurface temperature model of the hungarian part of the pannonian basin.– global and planetary change, 171, 48–64. doi: 10.1016/j.gloplacha.2017.09.020 benček, đ., bukovac, j., magaš, n. & šimunić, a. (2014): osnovna geološka karta republike hrvatske 1:100.000, list karlovac l33-92 [basic geological map of the republic of croatia 1:100.000, karlovac sheet – in croatian].– croatian geological survey, zagreb. benček, đ., bukovac, j., magaš, n. & šimunić, a. (2014): osnovna geološka karta republike hrvatske 1:100.000, tumač za list karlovac l33-92 [basic geological map of the republic of croatia 1:100.000, explanatory notes for karlovac sheet – in croatian].– croatian geological survey, zagreb, 85 p. borović, s., marković, t., larva, o., brkić, ž. & mraz, v. (2016): mineral and thermal waters in the croatian part of the pannonian bag eologia c roatica 307pavić et al.: a conceptual and numerical model of fluid flow and heat transport in the topusko hydrothermal system sin.– in: papić, p. (ed.): mineral and thermal waters of southeastern europe. springer, cham. borović, s., urumović, k., terzić, j. & pavičić, i. (2018): examining thermal conductivities of shallow subsurface materials for ground source heat pump utilization in the pannonian part of croatia.– the mining-geological-petroleum engineering bulletin, 33/5, 27–35. doi: 10.17794/rgn.2018.5.3 borović, s., pola, m., bačani, a. & urumović, k. (2019): constraining the recharge area of a hydrothermal system in fractured carbonates by numerical modelling.– geothermics, 82, 128–149. doi: 10.1016/j.geothermics.2019.05.017 brückl, e., behm, m., decker, k., grad, m., guterch, a., keller, g.r. & thybo, h. (2010): crustal structure and active tectonics in the eastern alps.– tectonics, 29/2. https://doi.org/10.1029/ 2009tc002491 bundschuh, j. & césar suárez, a.m. (2010): introduction to the numerical modeling of groundwater and geothermal systems.– crc press, london. 522 p. doi: 10.1201/b10499 bukovac, j., šušnjar, m., poljak, m. & čakalo, m. (1984): osnovna geološka karta sfrj 1:100.000, list črnomelj l33–91 [basic geological map of the republic of croatia, 1:100.000, črnomelj sheet – in croatian].– federal geological survey, belgrade. calcagno, p., baujard, c., guillou-frottier, l., dagallier, a. & genter, a. (2014): estimation of the deep geothermal potential within the tertiary limagne basin (french massif central): an integrated 3d geological and thermal approach.– geothermics, 51, 496–508. doi: 10.1016/j.geothermics.2014.02.002 cermak, v., & rybach, l. (1982): thermal properties: thermal conductivity and specific heat of minerals and rocks.– in: angeneister, g. (ed.): landolt-börnstein: zahlenwerte and funktionen aus naturwissenschaften und technik, neue serie, physikalische eigenschaften der gesteine. springer verlag, berlin, heidelberg and new york, v/1a, 305–343. cloetingh, s., cornu, t., ziegler, p.a., beekman, f. & entec working group (2006): neotectonics and intraplate continental topography of the northern alpine foreland.– earth. sci. rev., 74, 127–196. doi: 10.1016/j.earscirev.2005.06.001 crittenden, j.c., trussell, r.r., hand, d.w., howe, k.j. & tchobanoglous, g. (2012): mwh’s water treatment.– john wiley & sons, inc. doi: 10.1002/9781118131473 csontos, l. & vörös, a. (2004): mesozoic plate tectonic reconstruction of the carpathian region.– palaeogeogr. palaeoclimatol. palaeoecol., 210/1, 1–56. doi: 10.1016/j.palaeo.2004.02.033 d’agostino, n., avallone, a., cheloni, d., d’anastasio, e., mantenuto, s. & selvaggi, g. (2008): active tectonics of the adriatic region from gps and earthquake slip vectors.– journal of geo physical research: solid earth, 113/b12. https://doi.org/10.1029/ 2008jb005860 dhmz. (2021): monthly values and extremes.– državni hidrometeorološki zavod [croatian meteorological and hydrological service – in croatian]. (retrieved january 18, 2021) from https://meteo.hr/klima. php?section=klima_podaci&param=k2_1 diersch, h.j.g. (2014): feflow: finite element modeling of flow, mass and heat transport in porous and fractured media.– springer berlin, heidelberg. doi: 10.1007/978‐3‐642‐38739‐5 di napoli, r., martorana, r., orsi, g., aiuppa, a., camarda, m., de gregorio, s., gagliano candela, e., luzio, d., messina, n., pecoraino, g. et al. (2011): the structure of a hydrothermal system from an integrated geochemical, geophysical, and geological approach: the ischia island case study.– geochem. geophys. geosyst., 12/7. https://doi.org/10.1029/2010gc003476 domenico, p.a. & schwartz, f.w. (1997): physical and chemical hydrogeology (2nd edition).– wiley, new york. 506 p. domenico, p. a. & palciauskas, v. v. (1973): theoretical analysis of forced convective heat transfer in regional ground-water flow.– gsa bulletin, 84/12, 3803–3814. doi: 10.1130/0016-7606(1973)84<3803:tao fch>2.0.co;2 evans, m.a. & fischer, m.p. (2012): on the distribution of fluids in folds: a review of controlling factors and processes.– j. struct. geol., 44, 2–24. doi: 10.1016/j.jsg.2012.08.003 fabbri, p., pola, m., piccinini, l., zampieri, d., roghel, a. & dalla libera, n. (2017): monitoring, utilization and sustainable development of a low-temperature geothermal resource: a case study of the euganean geothermal field (ne, italy).– geothermics, 70, 281–294. doi: 10.1016/j.geothermics.2017.07.002. faulkner, d. r., jackson, c. a. l., lunn, r. j., schlische, r. w., shipton, z. k., wibberley, c. a. j., & withjack, m. o. (2010): a review of recent developments concerning the structure, mechanics and fluid f low properties of fault zones.– j. struct. geol., 32/11, 1557–1575. doi: 10.1016/j.jsg.2010.06.009 federal geological survey. (1970): geological map of sfry 1:500.000.– federal geological survey, beograd. fetter, c.w. (2001): applied hydrogeology (4th edition).– prentice hall, upper saddle river, new jersey. flóvenz, ó.g., hersir, g.p., sæmundsson, k., ármannsson, h. & fridriksson, t. (2012): geothermal energy exploration techniques.– in: sayigh, a. (ed.): comprehensive renewable energy, 51–95. doi: 10.1016/b978-0-08-087872-0.00705-8 fuchs, s. & balling, n. (2016): improving the temperature predictions of subsurface thermal models by using high-quality input data. part 1: uncertainty analysis of the thermal-conductivity parameterization.– geo thermics, 64, 42–54. doi: 10.1016/j.geothermics.2016.04.010 garg, s.k., pritchett, j.w., wannamaker, p.e. & combs, j. (2007): characterization of geothermal reservoirs with electrical surveys: beowawe geothermal field.– geothermics, 36/6, 487–517. doi: 10.1016/j.geothermics.2007.07.005 ghasemizadeh, r., hellweger, f., butscher, c. et al. (2012): review: groundwater flow and transport modeling of karst aquifers, with particular reference to the north coast limestone aquifer system of puerto rico.– hydrogeol j., 20, 1441–1461. doi: 10.1007/s10040-0120897-4 goldscheider, n., mádl-szőnyi, j., erőss, a. & schill, e. (2010): review: thermal water resources in carbonate rock aquifers.– hydrogeol. j., 18/6, 1303–1318. doi: 10.1007/s10040-010-0611-3 gorjanović-kramberger, d. (1905): geologijske i hidrografijske prilike oko topuskoga s obzirom na topuske terme [geological and hydrographic conditions in the area of topusko with respect to thermal spring – in croatian].– works of the yugoslav academy of sciences and arts – mathematics and science division, 37, 2–34. gorjanović-kramberger, d. (1917): geologijske i hidrografijske prilike oko topuskog s osobitim obzirom na topuske terme [geological and hydrographic conditions in the area of topusko with particular interest in thermal springs – in croatian].– reports of discussions in mathe matics and science division, yugoslav academy of sciences and arts, zagreb. grenerczy, g., sella, g.f., stein, s. & kenyeres, a., (2005): tectonic implications of the gps velocity field in the northern adriatic region.– geophys. res. lett., 32/16. doi: 10.1029/2005gl022947 havril, t., molson, j.w. & mádl-szőnyi, j. (2016): evolution of fluid flow and heat distribution over geological time scales at the margin of unconfined and confined carbonate sequences a numerical investigation based on the buda thermal karst analogue.– mar. and pet. geol., 78, 738–749. doi: 10.1016/j.marpetgeo.2016.10.001 heasler, h.p., jaworowski, c. & foley, d. (2009): geothermal systems and monitoring hydrothermal features.– in: young, r. & norby, l. (eds.): geological monitoring. geological society of america, boulder. doi:/10.1130/2009.monitoring(05) herak, d., herak, m. & tomljenović, b. (2009): seismicity and earthquake focal mechanisms in north-western croatia.– tectonophysics, 465/1–4, 212–220. doi: 10.1016/j.tecto.2008.12.005 https://doi.org/10.1016/j.marpetgeo.2016.10.001 https://doi.org/10.1130/2009.monitoring(05) g eo lo gi a c ro at ic a 308 geologia croatica 77/3 herak, m. & herak, d. (2023): properties of the petrinja (croatia) earthquake sequence of 2020–2021 – results of seismological research for the first six months of activity.– tectonophysics, 858, 229885. doi: 10.1016/j. tecto.2023.229885 horváth, f. & tari, g. (1999): the ibs pannonian basin project: a review of the main results and their bearings on hydrocarbon exploration.– geol. soc. london spec. publ., 156, 195–213. doi: 10.1144/gsl. sp.1999.156.01.11 horváth, f., bada, g., szafián, p., tari, g., ádám, a. & cloetingh, s. (2006): formation and deformation of the pannonian basin: constraints from observational data.– geological society memoir, 32, 191–206. doi: 10.1144/gsl.mem.2006.032.01.11 horváth, f., musitz, b., balázs, a., végh, a., uhrin, a., nádor, a., koroknai, b., pap, n., tóth, t. & wórum, g. (2015): evolution of the pannonian basin and its geothermal resources.– geothermics, 53, 328–352. doi: 10.1016/j.geothermics.2014.07.009 hounslow, a.w. (1995): water quality data: analysis and interpretation (1st ed.).– crc press. doi: 10.1201/9780203734117 hrvatović, h. (2005): geological guidebook through bosnia and herzegovina.– geological survey sarajevo-geology department,163 p. kaiser, b.o., cacace, m., & scheck-wenderoth, m. (2013): 3d coupled fluid and heat transport simulations of the northeast german basin and their sensitivity to the spatial discretization: different sensitivities for different mechanisms of heat transport.– environ. earth sci., 70/8, 3643–3659. doi: 10.1007/s12665-013-2249-7 kastelic, v. & carafa, m.m.c. (2012): fault slip rates for the active external dinarides thrust‐and‐fold belt.– tectonics, 31/3. doi: 10.1029/2011tc003022 khodayar, m. & björnsson, s. (2024): conventional geothermal systems and unconventional geothermal developments: an overview.– open j. geol., 14/2, 196–246. doi: 10.4236/ojg.2024.142012 korolija, b., živaljevićc, t. & šimunić, a. (1980): osnovna geološka karta sfrj 1:100.000, list slunj l 33–104 [basic geological map of sfry 1:100.000, slunj sheet – in croatian].– institute for geological research, zagreb, geological survey, sarajevo; federal geological survey, belgrade. korolija, b., živaljević, t. & šimunić, a. (1981): osnovna geološka karta sfrj 1:100.000, tumač za list slunj l33–104 [basic geological map of sfry 1:100.000, explanatory notes for slunj sheet – in croatian].– institute for geological research, zagreb; geological survey, sarajevo; federal geological survey: belgrade. kosović, i., briški, m., pavić, m., padovan, b., pavičić, i., matoš, b., pola m. & borović, s. (2023): reconstruction of fault architecture in the natural thermal spring area of daruvar hydrothermal system using surface geophysical investigations (croatia).– sustainability, 15/16,12134. doi: 10.3390/su151612134 kosović, i., matoš, b., pavičić, i., pola, m., mileusnić, m., pavić, m. & borović, s. (2024): geological modeling of a tectonically controlled hydrothermal system in the southwestern part of the pannonian basin (croatia).– front. earth sci., 12. doi: 10.3389/feart.2024.1401935 laloui, l. & rotta loria, a. f. (2020): heat and mass transfers in the context of energy geostructures.– in: analysis and design of energy geostructures. academic press., 69–135. doi: 10.1016/b978-0-12816223-1.00003-5 lei, h. & zhu, j. (2013): numerical modeling of exploitation and reinjection of the guantao geothermal reservoir in tanggu district, tianjin, china.– geothermics, 48, 60–68. doi: 10.1016/j.geothermics.2013.03.008 lenkey, l., dövényi, p., horváth, f. & cloetingh, s.a.p.l. (2002): geothermics of the pannonian basin and its bearing on the neotectonics.– in: cloetingh, s.a.p.l, horváth, f., bada, g. & lankreijer, a.c. (eds.): egu stephan mueller special publication series, 3, 29–40. doi: 10.5194/smsps-3-29-2002 macenić, m., kurevija, t. & medved, i. (2020): novel geothermal gradient map of the croatian part of the pannonian basin system based on data interpretation from 154 deep exploration wells.– renew. sustain. energy rev., 132. doi: 10.1016/j.rser.2020.110069 mádl-szőnyi, j. & tóth, á. (2015): basin-scale conceptual groundwater flow model for an unconfined and confined thick carbonate region.– hydrogeol. j., 23/7, 1359–1380. doi: 10.1007/s10040-015-1274-x majer, v. (1978): stijene “dijabaz-spilit-keratofirske asocijacije” u području abez-lasinja u pokuplju i baniji (hrvatska, jugoslavija) [rocks of diabase-spilite-keratophyre association in the area of abez-lasinja in pokuplje and banije (croatia, yugoslavia) – in croatian].– acta geol., 9/4, 42, 137–158. majer, v. (1993): ofiolitni kompleks banije s pokupljem u hrvatskoj i pastirevo u bosni [ophiolite complexes of banija and pokuplje in croatia and pastirevo in bosnia – in croatian].– acta geol., 23/2, 39–84. mandal, a., basantaray, a.k., chandroth, a. & mishra, u. (2019): integrated geophysical investigation to map shallow surface alteration/fracture zones of atri and tarabalo hot springs, odisha, india.– geothermics, 77, 24–33. doi: 10.1016/j.geothermics.2018.08.007 marini, l. (2000): geochemical techniques for the exploration and exploitation of geothermal energy.– dipartamento per lo studio del territorio e delle sue risorse, universita degli studi di genova, italy. martinsen, g., bessiere, h., caballero, y., koch, j., collados-lara, a. j., mansour, m., sallasmaa, o., pulido-velazquez, d., williams, n.h., zaadnoordijk, w.j. & stisen, s. (2022). developing a pan-european high-resolution groundwater recharge map – combining satellite data and national survey data using machine learning.– science of the total environment, 822 p. doi: 10.1016/j.scitotenv.2022.153464 mazor, e. (2004): chemical and isotopic groundwater hydrology, 3rd ed.– marcel dekker, new york, 13–179 p. moeck, i.s. (2014): catalog of geothermal play types based on geologic controls.– renewable and sustainable energy reviews, 37, 867–882. doi: 10.1016/j.rser.2014.05.032 montanari, d., minissale, a., doveri, m., gola, g., trumpy, e., santilano, a. & manzella, a. (2017): geothermal resources within carbonate reservoirs in western sicily (italy): a review.– earthscience reviews, 169, 180–201. doi: 10.1016/j.earscirev.2017.04.016 mroczek, e.k., milicich, s.d., bixley, p.f., sepulveda, f., bertrand, e.a., soengkono, s. et al. (2016): ohaaki geothermal system: refinement of a conceptual reservoir model.– geothermics, 59, 311–324. doi: 10.1016/j.geothermics.2015.09.002 muffler, p. & cataldi, r. (1978): methods for regional assessment of geothermal resources.– geothermics, 7/2–4, 53–89. doi: 10.1016/03756505(78)90002-0 nield, d.a. & bejan, a. (1999): convection in porous media (2nd edition).– springer, new york. doi:10.1007/978-1-4757-3033-3 ojha, l., karunatillake, s., karimi, s. & buffo, j. (2021): amagmatic hydrothermal systems on mars from radiogenic heat.– nat. commun., 12/1. doi: 10.1038/s41467-021-21762-8 pavelić, d. (2001): tectonostratigraphic model for the north croatian and north bosnian sector of the miocene pannonian basin system.– basin res., 13, 359–376. doi: 10.1046/j.0950-091x.2001.00155.x pavelić, d., kovačić, m., miknić, m., avanić, r., vrsaljko, d., bakrač, k., tišljar, j., galović, i. & bortek, ž. (2003): the evolution of the miocene environments in the slavonian mts. area (northern croatia).– in: vlahović, i. & tišljar, j. (eds.): 22nd ias meeting of sedimentology – opatija 2003, field trip guidebook. croatian geological survey, zagreb. pola, m., cacace, m., fabbri, p., piccinini, l., zampieri, d. & torresan, f. (2020): fault control on a thermal anomaly: conceptual and numerical modeling of a low-temperature geothermal system in the southern alps foreland basin (ne italy).– j. geophys. res. solid earth, 125/5, e2019jbo17394, doi: 10.1029/2019jb017394 pavić, m., kosović, i., pola, m., urumović, k., briški, m., & borović, s. (2023): multidisciplinary research of thermal springs area in topusko (croatia).– sustainability, 15/6, 5498. doi: 10.3390/ su15065498 pavić, m., briški, m., pola, m., & borović, s. (2024): hydrogeochemical and environmental isotope study of topusko thermal waters, crohttps://doi.org/10.4236/ojg.2024.142012 https://doi.org/10.1038/s41467-021-21762-8 g eologia c roatica 309pavić et al.: a conceptual and numerical model of fluid flow and heat transport in the topusko hydrothermal system atia.– environ. geochem. health, 46/4, 133. doi: 10.1007/s10653-02401904-9 pouraskarparast, z., aghaei, h., colombera, l., masoero, e. & ghaedi, m. (2024): fracture aperture: a review on fundamental concepts, estimation methods, applications, and research gaps.– mar. pet. geol., 164, 106818. doi: 10.1016/j.marpetgeo.2024.106818 prelogović, e., saftić, b., kuk, v., velić, j., dragaš, m. & lučić, d. (1998): tectonic activity in the croatian part of the pannonian basin.– tectonophysics, 297/1–4, 283–293. doi: 10.1016/s00401951(98)00173-5 rman, n. & tóth, g. (2011): hydrogeological conceptual model.– geological survey of slovenia, ljubljana; geological institute of hungary, budapest [in hungarian], 25 p. rman, n. (2014): analysis of long-term thermal water abstraction and its impact on low-temperature intergranular geothermal aquifers in the mura-zala basin, ne slovenia.– geothermics, 51, 214–227. doi: 10.1016/j.geothermics.2014.01.011 rman, n., bălan, l.l., bobovečki, i., gál, n., jolović, b., lapanje, a. et al. (2020): geothermal sources and utilization practice in six countries along the southern part of the pannonian basin.– environ. earth sci., 79, 1–12. doi: 10.1007/s12665-019-8746-6 royden, l.h., & horváth, f. (1988): the pannonian basin: a study in basin evolution.– american association of petroleum geologists. doi: 10.1306/m45474 saftić, b., velić, j., sztano, o., juhasz, g. & ivković, ž. (2003). tertiary subsurface facies, source rocks and hydrocarbon reservoirs in the sw part of the pannonian basin (northern croatia and south-western hungary). geologia croatica, 56/1, 101–122. doi:10.4154/232 scanlon, b., & dutton, a. (2000): groundwater recharge in texas.– the university of texas at austin, and marios sophocleous, kansas geological survey, lawrence, ks. scanlon, b.r., mace, r.e., barrett, m.e. & smith, b. (2003): can we simulate regional groundwater flow in a karst system using equivalent porous media models? case study, barton springs edwards aquifer, usa.– journal of hydrology, 2761–4, 137–158. doi: 10.1016/s00221694(03)00064-7 schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine-carpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss j. geosci., 101, 139–183. doi: 10.1007/s00015-008-1247-3 schmid, s. m., fügenschuh, b., kounov, a., maţenco, l., nievergelt, p., oberhänsli, r., pleuger, j., schefer, s., schuster, r., tomljenović, b., ustaszewski, k. & van hinsbergen, d.j.j. (2020): tectonic units of the alpine collision zone between eastern alps and western turkey.– gondwana research, 78, 308–374. doi: 10.1016/j.gr.2019.07.005 stevanović, z., dulić, i. & dunčić, m. (2015): some experiences in tapping deep thermal waters of the triassic karstic aquifer in the pannonian basin of serbia.– central european geology, 581–2, 50–61. doi: 10.1556/24.58.2015.1-2.3 stylianou, i., tassou, s., christodoulides, p., panayides, i. & florides, g. (2016): measurement and analysis of thermal properties of rocks for the compilation of geothermal maps of cyprus.– renewable energy, 88, 418–429. doi:10.1016/j.renene.2015.10.058" szanyi, j. & kovács, b. (2010): utilization of geothermal systems in south-east hungary.– geothermics, 39/4, 357–364. doi: 10.1016/j.geothermics.2010.09.004 šegotić, b. & šmit, i. (2007): studija optimirane energetske učinkovitosti korištenja geotermalnih voda [study of optimized energy efficiency of geothermal water use – in croatian].– unpublished report, termoinženjering-projektiranje, zagreb. šikić, k. (1990): osnovna geološka karta republike hrvatske 1:100.000, list bosanski novi l 33–105 [basic geological map of the republic of croatia 1:100.000, bosanski novi sheet – in croatian].– croatian geological survey, 2014. šikić, k. (1990): osnovna geološka karta republike hrvatske 1:100.000, tumač za list bosanski novi l 33-70 [basic geological map of the republic of croatia 1:100.000, explanatory notes for bosanski novi sheet – in croatian].– croatian geological survey zagreb, 2014. šimunić, a. (2008): topusko.– in: šimunić, a. & hećimović, i. (eds.): geotermalne i mineralne vode republike hrvatske [mineral and thermal waters of the republic of croatia – in croatian]. croatian geological survey, zagreb. tari, g., dövényi, p., dunkl, i., horváth, f., lenkey, l., stefanescu, m., szafián, p. & tóth, t (1999): lithospheric structure of the pannonian basin derived from seismic, gravity and geothermal data.– geol. soc. london spec. publ., 156, 215–250. doi: 10.1144/gsl. sp.1999.156.01.12 teutsch, g. & sauter, m. (1991): groundwater modeling in karst terranes: scale effects, data acquisition and field validation.– in: third conference on hydrogeology, ecology, monitoring, and management of ground water in karst terranes.– national ground water association, dublin, ohio,17–35. tomljenović, b. & csontos, l. (2001): neogene–quaternary structures in the border zone between alps, dinarides and pannonian basin (hrvatsko zagorje and karlovac basins, croatia).– int. j. earth sci., 90/3, 560–578. doi: 10.1007/s005310000176 tomljenović, b. (2002): strukturne značajke medvednice i samoborskog gorja [structural features of medvednica and samobor hills – in croatian].– unpubl. phd thesis, faculty of mining, geology and petroleum engineering, university of zagreb, zagreb. tomljenović, b., csontos, l., márton, e. & márton, p. (2008): tectonic evolution of the northwestern internal dinarides as constrained by structures and rotation of medvednica mountains, north croatia.– geol. soc. london spec. publ., 298/1, 145–167. doi: 10.1144/sp298.8 torresan, f., piccinini, l., cacace, m., pola, m., zampieri, d. & fabbri, p. (2022): numerical modeling as a tool for evaluating the renewability of geothermal resources: the case study of the euganean geothermal system (ne italy).– environ. geochem. health, 44/7, 2135–2162. doi: 10.1007/s10653-021-01028-4 tóth, j. (2009): gravitational systems of groundwater flow: theory, evaluation, utilization.– cambridge university press, cambridge. doi: 10.1017/ cbo9780511576546 turcotte, d.l. & schubert, g. (1982): geodynamics: applications of continuum mechanics to geological problems.– wiley, new york, 464 p. ustaszewski, k., schmid, s. m., fügenschuh, b., tischler, m., kissling, e. & spakman, w. (2008): a map-view restoration of the alpine-carpathian-dinaridic system for the early miocene.– swiss j. geosci., 101/suppl 1, 273-294. doi: 10.1007/s00015-008-1288-7 ustaszewski, k., kounov, a., schmid, s. m., schaltegger, u., krenn, e., frank, w. & fügenschuh, b. (2010): evolution of the adria-europe plate boundary in the northern dinarides: from continent-continent collision to back-arc extension.– tectonics, 29/6. doi: 10.1029/2010tc002668 ustaszewski, k., herak, m., tomljenović, b., herak, d. & matej, s. (2014): neotectonics of the dinarides-pannonian basin transition and possible earthquake sources in the banja luka epicentral area.– j. geodyn., 82, 52–68. doi: 10.1016/j.jog.2014.04.006 vass, i., tóth, t.m., szanyi, j. & kovács, b. (2018): hybrid numerical modelling of fluid and heat transport between the overpressured and gravitational flow systems of the pannonian basin.– geothermics, 72, 268–276. doi: 10.1016/j.geothermics.2017.11.013 velić, i. & sokač, b. (1982): novi nalazl naslaga donjeg i srednjeg trijasa u zapadnom kordunu (središnja hrvatska) [new discoveries of the lower and middle triassic in the western part of kordun area (central croatia) – in croatian].– geološki vjesnik, 35, 47–57. vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: palaeogeography, main events and depositional dynamics.– palaeogeogr. palaeoclimatol. palaeoecol., 220/3–4, 333–360. doi: 10.1016/j.palaeo.2005.01.011 https://doi.org/10.1556/24.58.2015.1-2.3 https://doi.org/10.1556/24.58.2015.1-2.3 https://doi.org/10.1016/j.geothermics.2017.11.013 g eo lo gi a c ro at ic a 310 geologia croatica 77/3 worthington, s.r.h., foley, a.e., & soley, r.w.n. (2019): transient characteristics of effective porosity and specific yield in bedrock aquifers.– j. hydrol., 578, 124129. doi: 10.1016/j.jhydrol.2019.124129 xiong, j., lin, h., ding, h., pei, h., rong, c. & liao, w. (2020): investigation on thermal property parameters characteristics of rocks and its influence factors.– natural gas industry b, 7/3, 298–308. doi: 10.1016/j. ngib.2020.04.001 url 1: https://www.avenza.com/avenza-maps/. accessed on 29 april, 2024. url 2: https://www.esri.com/news/arcnews/spring12articles/introducing-arcgis-101.html. accessed on 29 april, 2024. https://www.esri.com/news/arcnews/spring12articles/introducing-arcgis-101.html https://www.esri.com/news/arcnews/spring12articles/introducing-arcgis-101.html 2024 | 77/1 | 29–39 | 11 figs. | 2 suppl. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction 1.1. general background caves often have well preserved sediments that contain valuable palaeontological and archaeological materials, and consequently, cave sediments are interesting because they may contain important records of past environments. in croatia, the palynological analysis of cave sediments has rarely been performed (kurečić et al., 2021). cave palynological investigations in the surrounding region are also scarce (doláková, 2014; d’agostino et al., 2022). even though palynology is very promising, it is also very challenging. pollen taphonomy in caves depends on a diverse number of factors: primarily production, dispersal, transport, deposition and post-depositional processes (coles et al., 1989; hunt & fiacconi, 2018). the impact of animals and humans upon the composition of palynomorph assemblages is also very important. therefore, the aim of this study was to apply a combination of palynofacies and palynomorph analyses in cave sediment research. more specific objectives were: (i) to obtain additional information about the local vegetation plant cover in the past of the adriatic area, (ii) to obtain information about temporal changes in the vegetation of that area, and (iii) to enable a better understanding of the post-depositional processes affecting the palynomorph assemblage. 1.2. location, physical environment and vegetation spila nad procjepom cave (also known as the briježica or špilja kod nerezinoga dola) is situated on the southern slope of briježina hill at 210 m a.s.l. overlooking procjep bay in the mljet national park (fig. 1). the cave is a 35 m long chamber partly filled with sediments, formed in the jurassic–cretaceous dolostones with first palynological results from spila nad procjepom cave, mljet island (croatia) koraljka bakrač 1, olena sirenko 1,5, dario hruševar 2,*, ivona baniček1, vibor novak3, nataša kletečki4 and ankica oros sršen3 1 croatian geological survey, department of geology, sachsova 2, hr-10000 zagreb, croatia; (kbakrac@hgi-cgs.hr, osirenko@hgi-cgs.hr, ibanicek@hgi-cgs.hr) 2 university of zagreb, faculty of science, department of biology, horvatovac 102a, hr-10000 zagreb, croatia; (*corresponding author: dario.hrusevar@biol.pmf.unizg.hr) 3 croatian academy of sciences and arts, institute for quaternary palaeontology and geology, ante kovačića 5, hr-10000 zagreb, croatia; (aos@hazu.hr, vnovak@hazu.hr) 4 elementary school bogumil toni, perkovčeva 90, hr-10430 samobor, croatia; (natasa.kletecki@gmail.com) 5 the national academy of sciences of ukraine, institute of geological science, k55b o. gonchara str., 01054 kyiv, ukraine; (o_sirenko@ukr.net) doi: 10.4154/gc.2024.04 abstract this paper presents the first results of palynological research from the spila nad procjepom cave, situated in the mljet national park, croatia. the palynological data obtained, enables a partial insight into the local vegetation cover, temporal changes in the vegetation during the accumulation of studied deposits (at ca. 3500 cal years bp), and post-depositional processes that influenced the palynomorph assemblage. results of palynofacies analysis indicate changes from fluvial (channel deposits), through palustrine to terrestrial environments. although the interpretation of changes in plant cover, due to the lack of statistical significance, should be taken with caution, preserved pollen types confirm the dominance of the mediterranean evergreen forest vegetation on mljet island. moreover, a high proportion of non-arboreal pollen (nap) indicates some level of forest degradation, ranging from mediterranean open forest to degraded maquis. abundant charcoal additionaly confirms that the cave was inhabited by humans. limestone intercalations (husinec, 2002). the entrance (dimension 6 x 2 m) is oriented towards the southwest and the open sea. the entrance part of the cave is dry with a few remains of the flowstones that are no longer active, while the back of the cave is hydrologically active where drip water is still circulating, and flowstones are growing. the sediments studied in this research were sampled from the se profile of test pit sonda ii in the back part of the cave, in the vicinity of a large flowstone (fig. 2). the area of the mljet national park, as well as the entire island, belongs to the macro-geomorphological region of south dalmatia, with the archipelago and the meso-geomorphological region of the south dalmatian archipelago (bognar, 1999). according to köppen’s classification, the island of mljet belongs to the mediterranean climate with hot summers (csa) (šegota & filipčić, 2003). it means that winters are mild with abundant rainfall, in opposition to the long, dry and hot summers with frequent sunny days. the average annual air temperature on the island is 16.7 °c and it is one of the warmest areas in croatia. the amplitude of average monthly air temperature values indicates the large thermal influence of the sea. spring is cooler (due to the marine cooling effect) than the relatively warm autumn. the lowest mean monthly temperature is measured in january and february (8.8 °c each) and the highest values in july and august (26.0 °c and 25.8 °c, respectively). average annual precipitation varies between 815 mm and 1021 mm, depending on the location and altitude (španjol et al., 2016). due to its geographical position, the island of mljet is located in the mediterranean biogeographical region. plant cover of the island belongs to the stenomediterranean (near coastline), eumediterranean (inland area) and hemimediterranean (inland higher altitudes) vegetation zones (trinajstić, 1998; španjol et al., 2016). only in the article history: manuscript recieved: december 08, 2023 revised manuscript accepted: february 13, 2024 available online: february 27, 2024 keywords: adriatic sea, holocene, hydrological changes, mediterranean biogeographical region, palynofacies, palynomorphs, palaeoenvironment, pollen mailto:ibanicek@hgi-cgs.hr mailto:dario.hrusevar@biol.pmf.unizg.hr mailto:vnovak@hazu.hr mailto:natasa.kletecki@gmail.com mailto:o_sirenko@ukr.net g eo lo gi a c ro at ic a geologia croatica 77/130 latter zone, do deciduous plants with a focus on ostrya carpinifolia scop. have an important role (trinajstić, 1998). the other two vegetation zones are dominantly evergreen. so even though the island is nowadays almost completely covered with evergreen forest vegetation, it was not the case in the past. forest habitats are the dominant type of vegetation, occupying more than three quarters of the island area (mesić et al., 2009). today the dominant forest trees are holm oak (quercus ilex l.) and aleppo pine (pinus halepensis l.). most of the national park is overgrown by maquis (španjol et al., 2016), and various degradation stages of holm oak forests (ugarković et al., 2019), while garrigues vegetation occupies only a small area (mesić et al., 2009). the most abundant species of the maquis layer are evergreen trees, such as the strawberry tree (arbutus unedo l.), mock privet (phillyrea media l.), tree heath (erica arborea l.), chios mastic (pistacia lentiscus l.), common myrtle (myrtus communis l.) and laurustinus (viburnum tinus l.), followed by carob (ceratonia siliqua l.), olive (olea europaea l. var. sylvestris brot.), laurel (laurus nobilis l.), and others. among conifers, the most abundant is the genus juniperus represented by brown-berried juniper (juniperus oxycedrus l. ssp. oxycedrus), large-berried juniper (juniperus oxycedrus l. ssp. macrocarpa (sm.) ball) and phoenicean juniper (juniperus phoenicea l.). pine forests, after maquis, represent the most abundant form of forest vegetation in the park, while the large preserved aleppo pine trees testify to the widespread appearance of the former autochthonous pine forests of mljet (španjol et al., 2016). 1.3. previous palynological and archaeological research the island of mljet has been palynologically investigated several times, e.g. beug (1967), jahns & van den bogaard (1998), and jahns (2002) so the holocene vegetation changes are mostly well known. according to jahns (2002) who brings a synthesis of palaeovegetational changes, in the period preceding the common era, four main steps in vegetation development can be recognized: the deciduous quercus woodland was refigure 1. geographical location (red dot) and the entrance of the spila nad procjepom cave (island of mljet). figure 2. plan of the spila nad procjepom cave with locations of the test pits sonda i (s i) and sonda ii (sii). sampled profile of sii is marked with a bold line. g eologia c roatica bakrač et al.: first palynological results from spila nad procjepom cave, mljet island (croatia) 31 placed by the evergreen juniperus-phillyrea community before ca. 7500 years bp, the latter was succeeded by the evergreen quercus ilex woodland ca. 6000 years bp, followed by the pinus dominated forest shortly after ca. 3000 years bp. archaeologically and palaeontologically, the spila nad procjepom cave was investigated during five campaigns over the last 12 years (from 2010 to 2022) in collaboration with the public institution of the “mljet national park”. two test pits were dug: sonda i (“s i”) near the entrance and sonda ii (“s ii”) in the inner part of the cave. while the silty, topmost sediments were rich in the remains of domesticated animals (mainly sheep and goats), marine fauna (fish and molluscs) and archaeological material (mainly pottery) spanning from the copper age to medieval time (oros sršen et al., 2013; mauch lenardić et al., 2017), the flowstone discovered beneath provided a much older age. the sediment deposition in the cave lasted at least from the last interglacial (mis 5e), however, the breccia and the dolostone debris beneath could be of mis 6 age or older (oros sršen et al., 2017). 2. materials and methods 2.1. fieldwork three palynological samples were taken from the sonda ii (“s ii”) test pit in order to investigate the preservation of palaeobotanical remains in the cave deposits of spila nad procjepom. test pit “s ii” was chosen due to its well-preserved layers. the frontlayer of the soil was cleared to a depth of 5 cm, and discarded to eliminate potential contaminants. three samples were taken from the southeastern profile of the pit (fig. 3), from different sublayers of layer 4 that were chosen for its well-preserved fine-grained sediments. layer 4 is mostly grayish brown silty clay (10yr-4/2) with various amounts of charcoal, hearth ash, as well as some burnt clay. all sublayers contain excellently preserved holocene palaeontological/zooarchaeological remains, including sheep and goats and marine molluscs, as well as prehistoric archaeological material: pottery and a few stone tools (oros sršen et al., 2013). samples for palynology were taken from the grayish-brown sediment that represents deposits less affected by human-produced fire (hearths – white/orange inclusions of profile on fig. 3): • sample p1 – layer 4, sublayer 3: overall sediment is yellowish-brown silty clay with charcoal particles and intercalations of grayish clay. visible burrowing holes point to recent bioturbation. sample p1 was taken at a depth of 0,60 m from the pit surface (sediment top). • sample p2 – layer 4, sublayer 4: mostly reddish-brown silty clay with numerous charcoal hearth remains, with intercalations of dark brown to gray silty clay. sample p2 was taken at a depth of 0,80 m from the pit surface (sediment top). • sample p3 – layer 4, sublayer 4: mostly grayish-brown silty clay with reddish and yellowish intercalations and traces of ash. sample p3 was taken at a depth of 1,10 m from the pit surface (sediment top). one charcoal sample (z – 5203) was collected from the hearth in layer 4, sublayer 4 at 0,90 m from the pit surface during the excavation in 2012. the position of the hearth is 10 cm below sample p2. the charcoal sample was sent for radiocarbon dating (ams 14c) at the institute of ruđer bošković in collaboration with the university of georgia, center for applied isotope studies. it is calibrated by intcal20.14c (reimer et al., 2020), with the error at the 1σ-level. 2.2. laboratory work 2.2.1. sample preparation the samples were processed for palynological analysis in the laboratory of the croatian geological survey. for each sample apfigure 3. sampling spots (p1, p2, p3) of layer 4 (sonda ii test pit). g eo lo gi a c ro at ic a geologia croatica 77/132 prox. 18-30 g sediment was cleaned and crushed. two lycopodium tablets (batch no. 280821291; 13761 spores/tablet) were added to each sample at the start of the processing to calculate palynomorph concentration according to maher (1981). the preparation procedure included treatment with cold hcl (20%) to remove the carbonates, and sodium pyrophosphate (na4p2o7) to prevent coagulation, according to the standard techniques described in moore et al. (1991). heavy liquid (zncl2, specific gravity 2.1 kg/l) was applied to separate the organic matter from the undissolved inorganic fraction. the organic residue was sieved through a 10 µm mesh. for palynofacies analysis slides were mounted in glycerin jelly, and the rest of the material was mixed in silicon oil for palynomorph analysis. microscopic analyses were performed using a leica dm2500 microscope at x50, x100, x200, x400 and x630 magnifications combined with the differential interference contrast (dic). photomicrographs were taken using a leica mc190 hd camera connected to the leica las ez software. sediment samples, organic residues and palynological slides are curated at the department of geology, croatian geological survey. 2.2.2. palynofacies analysis for palynofacies analysis, a minimum of 300 sedimentary organic particles were counted. there are three main categories: amorphous organic matter (aom), phytoclasts and palynomorphs (tyson, 1995). in this paper, we distinguish subcategories: preserved phytoclasts (translucent, yellow-green plant tissue, and brown-black biostructured wood) and transformed phytoclasts (amorphous particles, gelified particles, and charcoal). amorphous particles (ap) appear with diffuse but recognizable outlines that occasionally have residual internal structures. gelified particles (gp) present a homogeneous texture, variable colour (brown to amber), true outlines, and commonly angular shape, only occasionally with dulled angles. charcoal particles are completely opaque, angular, and usually planar, black fragments. samples are plotted in ternary diagrams using the software past 4.13 (hammer et al., 2001). we used different types of diagrams to present the results. one of the more comprehensive diagrams used in palynofacies studies is the app diagram (aom-phytoclast-palynomorph ternary diagram) presenting differences in relative proximity to terrestrial organic matter sources, transport paths, and the redox status of the depositional environments (tyson, 1995). we also used two more ternary diagrams: “amorphous om/preserved phytoclasts/ transformed phytoclasts” and “opaque/amorphous/gelified particles” (op/ap/gp) to estimate the origin of the sedimentary organic matter (som) (aquatic/terrestrial), its source areas (vegetation, soils, river), and controls of early diagenetic changes (aerobic/anaerobic conditions, advanced oxidation) introduced by sebag et al. (2006b). to illustrate the origin (i.e. terrestrial or aquatic) and state of degradation of the organic particles samples, sebag et al. (2006b) proposed four optical indices: (i) “aom contents” to quantify the aquatic contribution; (ii) “preserved phytoclasts / transformed phytoclasts ratio” to calculate the degree of degradation of the terrestrial fraction; (iii) “op contents” to distinguish the allochthonous fraction from the fluvial origin; (iv) “gp/ap ratio” to differentiate the pedogenic or subaquatic degradation of terrestrial plant debris. to obtain information about the origin of the terrestrial fraction, we plotted a diagram with “op contents” and “gp/ap ratio”. in order to have an overview of the organic particle amounts in the sediments, we introduced “om concentration” (particles/g) that is calculated by the following formula: oc = ((number of lycopodium spores added) x (number of particles counted)) / ((number of lycopodium spores counted) x (weight of dry sediment processed in grams)). 2.2.3. charcoal analysis samples for microscopic charcoal analysis were prepared as part of routine pollen analysis. they were counted as palynofacies particles. particles in the < 50 µm size bracket were not measured because of their great abundance and minimal influence on the total charcoal sum, according to whitlock & larsen (2001). macroscopic charcoal (> 100 µm) was analysed from sediment sieved at 125 µm during the preparation procedure for pollen analysis. all particles that were black with shiny surfaces were considered to represent charcoal fragments. a qualitative approach was used to gain a general view of the fire history. identification of pollen and plant spores followed standard keys, eg. moore et al. (1991) and beug (2015). a minimum of 100 palynomorphs were counted (five to six slides per sample) because the abundance was very low. all terrestrial pollen and spores were included in the pollen calculation sum. indeterminable pollen counts were included in the total pollen sum because exclusion could result in bias in favour of well-preserved types (kapp et al., 2000). when calculating the palynomorph percentages, the sum of all established pollen grains and spores, excluding algae and modern spores, was taken as 100%. the determination of pollen and spores was carried out according to the engler classification system. palynological results, including changes in the arboreal/non-arboreal pollen (ap/nap, i.e. woody vs. herbaceous plants), were presented as pollen percentage histograms, tables, and plates. 3. results 3.1. radiocarbon dating the radiocarbon date of one charcoal sample (z – 5203/ugams 14722) has yielded a date of 3160±25 years bp (3276 – 3448 cal years bp/ 1439 cal years bc). 3.2. palynofacies organic matter concentrations are relatively high ranging from 53.254 (sp22 p2) to 155.923 (sp22 p3) particles per gram. pafigure 4. phytoclasts ratio. g eologia c roatica bakrač et al.: first palynological results from spila nad procjepom cave, mljet island (croatia) 33 lynofacies of all three studied samples are dominated by phytoclasts (suppl. 1), mostly degraded woody tissue. translucent, yellow-green plant tissue (cuticle and membranous fragments) and amorphous organic matter are very rare (fig. 4). in all three samples macroscopic charcoal (>100 µm) is abundant (fig. 5 a,c,e). in sample sp22 p3 charcoal is the most abundant particle type. its ratio decreases in sample sp22 p2 and it has the lowest abundance in palynofacies of sample sp22 p1. at the same time, in sample sp22 p1 the degraded wood ratio increases, as well as the brown-black biostructured wood clasts (fig. 5). 3.3. palynomorphs palynomorph concentrations are relatively low ranging from 1366 to 3225 palynomorphs per gram (suppl. 2). the obtained materials made it possible to establish three spore-pollen complexes that characterize the deposits of the spila nad procjepom cave. selected samples of palynomorphs are given in fig. 6. in the established complexes, the pollen of woody and herbaceous plants is approximately equal in proportions. however, they have several differences (suppl. 2). it is important to note that in the macerates of all samples, redeposited pollen from more ancient deposits was noted in different amounts, as well as modern spores of polypodiaceae 3.3.1. sp22 p3 the palynomorph assemblage of sample sp22 p3 comprises 33.8% ap and 35.3% nap. distinctive features of the assemblage are the highest percentage of spores (20.7%) of all three samples, belonging mainly to polypodiaceae, the lowest amount of ericaceae pollen (1.7%), as well as the highest content and taxonomic diversity of pollen from aquatic plants (suppl. 2). the group of woody plants is dominated by oleaceae pollen (23.2%) and closely followed by pinus pollen (13.9%). the group of herbaceous plants is dominated by cichoriaceae pollen (12.2%). the pollen of poaceae and asteraceae was recorded in approximately equal proportions, at 6.9% and 5.2%, respectively, with valeriana pollen at 2.6%. single pollen grains of caryophyllaceae and lamiaceae were also noted (suppl. 2). a characteristic feature of the complex is the highest content and taxonomic diversity of hygrophilous pollen: сyperaceae (2.6%), typha latifolia (1.7%), figure 5. palynofacies sp 22 p-1 a-b; sp 22 p-2 c-d; sp 22 p-3 e-f. the scale bar is 200 µm for a, c, e and 50 µm for b, d, f. g eo lo gi a c ro at ic a geologia croatica 77/134 liliaceae (1.7%), alismataceae (0.8%). the highest number of spores of polypodiaceae was also recorded in sample sp22 p3 (suppl. 2). 3.3.2. sp22 p2 in the palynomorph assemblage of sample sp22 p2, the ap reaches 43.8%. compared to the assemblage described above, the amount of pinus pollen in its composition has decreased to 9.3%. however, the composition of prevailing pollen types, as well as the amount of oleaceae pollen, remained at the level of the previous sample complex (22.2%). a distinctive feature of the complex is the relatively high content of ericaceae pollen (11.2%) and the appearance of celastraceae pollen. compared to the previous complex, the nap amount has slightly increased (39.8%). this group doubled the amount of asteraceae pollen (11.9%), with an accompanying high percentage of cichoriaceae pollen (15.7%). poaceae pollen content decreased to 5.9%, and only a single ephedra pollen grain was noted. compared to the previous palynomorph assemblage, the amount of caryophyllaceae pollen has doubled (1.9%), while valeriana pollen reached 1.9%. aquatic plants are represented by typha latifolia pollen (2.6%). the spores belong mainly to polypodiaceae and sporadically to selaginella. a pseudoschizaea algae was also recorded (suppl. 2). 3.3.3. sp22 p1 the palynomorph assemblage of the sp22 p1 sample reaches 44.2% of ap, while this group contains the highest quantities of pinus pollen (18.5%). the composition of angiosperm pollen is dominated by pollen grains of oleaceae (18.5%). ericaceae (4.8%) is of subordinate importance. a distinctive feature of the figure 6. palynomorphs from the deposits of the spila and procjepom cave: (a)-(b) pinus, (c) oleaceae, (d)-(e) ericaceae, (f )-(g) asteraceae, (h) chenopodiaceae, (i)-(j) poaceae, (k) caryophyllaceae, (l)-(m) cichoriaceae, (n) celastraceae, (o) artemisia, (p) liliaceae, (q) cyperaceae, (r)-(s) polypodiaceae, (t) selaginella, (u) anogramma, (v) redeposited pollen, (w) pseudoschizaea. the scale bar is 20 μm. g eologia c roatica bakrač et al.: first palynological results from spila nad procjepom cave, mljet island (croatia) 35 complex in sample sp22 p1 is the presence of pollen from broadleaved species: quercus, ostrya and acer (in total 2.4%). the ap and nap are equal in proportion (44.2%). this group is dominated by the pollen of cichoriaceae (13.2%) and asteraceae (11.7%). the pollen of poaceae (8.5%) acts as a subdominant. pollen grains of caryophyllaceae (3.2%) and artemisia (1.5%), valeriana (1.5%), as well as single pollen from solanaceae and lamiaceae were observed. the group of aquatic plants is represented by the pollen of typha latifolia (1.5%). spores belong mainly to polypodiaceae. also, single spores of anogramma, as well as the alga pseudoschizaea were noted. 4. discussion 4.1. depositional environment a relatively small amount of organic residue in all three samples with a high proportion of the opaque or semi-opaque phytoclasts indicates an oxic environment (tyson, 1995), where other organic compounds are selectively destroyed. the app diagram (fig. 7) shows the absolute domination of phytoclasts in all the analysed samples, indicating a pronounced input of terrestrial organic material (tyson, 1995). the dominance of structured phytoclasts in the total organic residue in all of the analysed samples indicates the pronounced input of terrestrial organic components. short fluvial transport is evident in phytoclasts’ structure, angularity and the fact that the clasts are unsorted (tyson, 1995; mendonça filho et al., 2017). black oxidized phytoclasts (charcoal) were derived from fires (wildfires or anthropogenic fires), providing direct evidence of burning (tyson, 1993; 1995). in the microscopic material, opaque particles are not always charcoal, but rather gelified phytoclasts because higher temperatures convert the material to ash through glowing combustion, while lower temperatures may only lightly scorch the material, but not char it (whitlock & larsen, 2001). since charcoal is produced between temperatures of 280°c and 500°c, microscopic charcoal abundance increases during local fires. however, other proxy records, such as macroscopic charcoal or lithological changes, are needed to confirm if the fire was local. abundant macroscopic charcoal (>100 µm) in all of the samples, coupled with charcoal, hearth ash, and some burnt clay in sediment, confirms the local fire event. the “preserved/transformed phytoclasts ratio” allows quantification of the degree of degradation of the terrestrial fraction. in the “aom/preserved phytoclasts/transformed particles” ternary diagram (fig. 8), the domination of transformed particles indicates a high plant-derived content (sebag et al., 2006a). sebag et al. (2006a) concluded that the “preserved/transformed phytoclast ratio” decreases from production (i.e. litters) to depositional area (ditch, pond, alluvial deposits, etc.). in samples from the spila nad procjepom cave, the abundance of transformed particles points towards the soil origin. typical soil assemblages are dominated by transformed phytoclasts (sebag et al., 2006a). the ratio between opaque, amorphous, and gelified particles is presented in the “opaque/amorphous/gelified particles” ternary diagram (fig. 9). more illustrative is the diagram of the “op” and “gp/ap ratio” (fig. 10). the “op contents” increases with the oxidation of terrestrial figure 7. palynofacies (app) ternary diagram. figure 8. amorphous om/ preserved phytoclasts/ transformed phytoclasts ternary diagram. figure 9. opaque/ amorphous/ gelifies particles (op/ap/gp) ternary diagram. figure 10. origin of the terrestrial fraction. g eo lo gi a c ro at ic a geologia croatica 77/136 over periods of time (fig. 11, suppl. 2). although our pollen samples are not statistically significant due to the low pollen counts, well represented oleaceae pollen speak in favour of olive-dominated stands at a distance of less than 500 meters from the cave (florenzano et al., 2017). moreover, the aerobiological research conducted in babino polje, the largest settlement on the island of mljet whose inhabitants are mainly involved in the olive and vine cultivation, confirmed the relative dominance of airborn oleaceae pollen in recent time (volarić-mršić, 1984). in contrast, pine pollen is not overrepresented as it may be expected due to recent plant cover on the island of mljet, suggesting that pinus probably did not participate in the local or extra-local vegetation. according to connor et al. (2004), pine trees are found near the sampling site only when its pollen comprises 35-50%, and these values were not reached in any of the studied samples. within the herbaceous plants, pollen from cichoriaceae, asteraceae, poaceae, chenopodiaceae, and caryophyllaceae were well represented. these families also include the largest number of drought-resistant taxa which complete their life cycle in one growing season and survive unfavourable conditions in the form of seeds. additionally, caryophyllaceae, poaceae and chenopodiaceae are indicators of open-ground vegetation in the mediterranean area (fyfe et al., 2018; izdebski et al., 2020). thus, herbaceous vegetation of all of the afore-mentioned taxa is widespread in the recent island flora (regula-bevilacqua & ilijani, 1984), as it was during the late quaternary in the broader mediterranean area (suc et al.). locally, the hydromorphic conditions are marked by the presence of typha latifolia in all the analysed samples. this aquatic taxon is a common wetland element and refers to water depths within the range of 10–60 (–100) cm (šumberová, 2011), and requires a mean july temperature above 15.7 °c (schenk et al., 2018). the aquatic-wetland component is highlighted in the sp22 p3 sample by the appearance of alismataceae and cyperacea pollen and the highest percentage of spores. our results correlate very well with the zonation presented for southern dalmatia by jahns (2002) and bass (2008). jahns & van den bogaard (1998) divided the quercus ilex period into three subzones (c1-c3). whereas the q. ilex remains at a relatively constant level, the associated vegetation is different. in subzone c1 juniperus dominate, in subzone c2 erica and in subzone c3 pinus. in the samples from spila nad procjepom, ericaceae have greater values than others and we can presume that the sediment in the cave was deposited during the subzone c2 (quercus ilex – erica) ranging from approximately 4370 years bp to 2670 years bp (jahns, 2002), which is in accordance with our radiocarbon dating. furthermore, detailed sedimentological analyses are planned in order to shed more light on the genesis of the sediments and cave. 4.3. taphonomic processes it is known that periodic wetting and drying of cave deposits as well as human activity (burning) can lead to extremely poor pollen preservation (hunt & fiacconi, 2018). pollen taphonomy in caves depends solely on transport paths and the depositional environment. contemporary pollen must have entered the cave via aeolian transport or fluvial input or was brought in by animals/humans. animals could have easily picked up pollen from foliage in the vicinity of the cave during grazing and brought it to the cave on their fur and feet or in their gut contents (coles et al., 1989). daisy family, asteraceae (entomophilous pollen), which have a great share in the pollen assemblage from spila nad source materials. the “gp/ap ratio” is used to discriminate sites that have material reworked from the soil as opposed to sites where fresh plant debris falls directly into a basin and decays (sebag et al., 2006b). “op contents” allows the recognition of fluvial (high values) and palustrine (low values) environments. the “gp/ap ratio” allows the distinction of soil (low values) and plant (high values) supplied areas. gp formation is related to the degradation of plant tissues in aquatic environments (pools, ponds, lakes) or anaerobic conditions (catotelm of peat, hydromorphic soils). it is often observed in hydromorphic soils (noël et al., 2001). in the analysed samples, the domination of gp points to the degradation of plant tissues in aquatic and/or anaerobic conditions, especially in the sample sp22 p1, derived from hydromorphic soils, while sp22 p2 and sp22 p3 indicate a fluvial influence. comparing the data from this study with data presented by sebag et al. (2006b), sp22 p3 could be indicative of a fluvial origin (channel deposits), sp22 p2 of palustrine, and sp22 p1 of terrestrial origin (of horizons sensu baize & girard (2009) related to oe horizons (orthoeutric) from the world reference base (iuss working group wrb, 2007, 2014)), moderately decomposed organic matter. a similar situation to sample sp22 p3 was observed in the lower cerovačka cave (mt. velebit, croatia) where sample dc-sp 1 indicates a fluvial palaeoenvironment confirmed by sedimentological data (kurečić et al., 2021). 4.2. vegetation history due to a limited number of samples, and the fact that there was no sample taken from the surface near the entrance of the cave, which is a prerequisite for palaeofloristic reconstructions, the presented reconstructions of vegetation have a preliminary character. considering the above facts, the materials for the palynological study did not allow biostratigraphic dating of the analysed sediments, which is only a partial obstacle in the interpretation of local temporal changes in vegetation. in all the studied deposits (sp22 p3, sp22 p2 and sp22 p1), oleaceae were the principal, dominant component within the woody plants, while the composition of subdominants changed figure 11. composition of plant groups during the formation of deposits in the spila cave. g eologia c roatica bakrač et al.: first palynological results from spila nad procjepom cave, mljet island (croatia) 37 procjepom cave could have been brought by bees, flies or beetles (hunt & fiacconi, 2018). this is in accordance with navarro et al. (2001) who concluded that the amount of the zoophilous pollen (asteraceae/cichorioideae) increased from the direction of the cave entrance into the inner parts. ground-living animals such as foxes, badgers, porcupines and rodents may be significant importers of pollen (hunt & fiacconi, 2018). in the spila nad procjepom cave, a small amount of rodents’ remains were recorded (mauch lenardić et al., 2017). according to connor et al. (2004), pinus pollen was probably brought from the other areas. although quercus ilex forests were recorded in the previous palynological research conducted on cores taken from the mljet lakes (jahns & van den bogaard, 1998; jahns 2002), and it is native to the island, a statistically non-relevant amount of its pollen was found in the cave sediment. this could be due to preservation or accumulation factors. quercus pollen could be under-represented because of its susceptibility to corrosion and oxidation (havinga, 1964). he noted that the percentage of quercus in the original pollen flora is much higher than in pollen found in sediment. an alternative cause for the evergreen oak decline in the vegetation record could be due to anthropogenic influence during the greco-roman colonization of the eastern adriatic shores (bass 2008). on the other hand, ericaceae pollen is abundantly represented. more plausible than the idea of differential preservation is that animals, like sheep and goats, the remains of which were found in these sediments (bass, 2008; oros sršen et al., 2013), influenced the pollen distribution more than wind or water. they could have easily picked up pollen from foliage in the vicinity of the cave during grazing. findings of the palynomorph pseudoschizaea, probably related to the zygnemataceae family, indicate the runoff due to periods of enhanced soil erosion (leroy et al., 2007) confirmed by palynofacies. estiarte et al. (2008) also point out that pseudoschizaea is indicative of erosive processes, particularly when occurring with taxa such as asteraceae, that are known as markers of edaphic processes. this is also the case in spila and is confirmed by the palynofacies indicating the pronounced input of terrestrial organic material. van de schootbrugge et al. (2024) concluded that chomotriletes is the valid senior synonym of a variety of taxa, including pseudoschizaea and concentricystes. they considered it as a freshwater organism cyst, dominant in floodplain soils and ephemeral freshwater lakes. since polypodium is highly resistant to oxidation and corrosion (havinga, 1964) it could be over-represented in samples from the soil. on the other hand, some forms that are not resistant to oxidation and corrosion are poorly preserved and indeterminable. 5. conclusions the obtained data showed the effectiveness and prospects of complex palaeontological research in the study of cave sediments. results of palynological analysis enable a partial insight into the local plant cover, temporal changes in the vegetation during the accumulation of studied deposits and post-depositional processes that influence the palynomorph assemblage. according to the results of palynofacies analysis, the provenance of the deposited samples ranges from a fluvial environment (channel deposits), through palustrine to hydromorphic soils. the results of the sporepollen analysis allowed reconstruction of the differences in the composition of the vegetation cover that existed during the accumulation of the studied sediments. in all three analysed samples, the proportion of ap is slightly higher than nap. moreover, in all samples, oleaceae pollen forms the basis of forest vegetation. the fact that pine pollen is not overrepresented, and olive pollen is present in the same quantity, indicates that the former was presumably absent from local/extra-local vegetation, and the latter probably grew nearby. although the interpretation of changes in plant cover, due to the lack of statistical significance, should be taken with caution, preserved pollen types confirm the dominance of the mediterranean evergreen forest vegetation on the island of mljet. additionally, a high proportion of nap pollen types indicate some level of forest degradation, ranging from mediterranean open forest to degraded maquis. sediment was most likely deposited during the subzone c2 (quercus ilex – erica) ranging from approximately 4370 years bp to 2670 years bp which was confirmed by radiometric dating. the biostratigraphic dating of sediments, as well as the detailed reconstructions of palaeoenvironments, is possible only with the use of multidisciplinary studies including a broader set of analyses (e. g. palaeomagnetism, cosmogenic 26al/10be burial dating of coarse sediment, environmental magnetic studies of speleothems) and interpretation. therefore, more detailed research is planned and will continue at the spilja nad procjepom cave shortly, to offer a more comprehensive insight into the depositional palaeoenvironment. acknowledgment this study was supported by the foundation of the croatian academy of sciences and arts, project preliminarny palaeobotanical investigations of the spila nad procjepom cave in national park mljet and public institution “mljet national park” and by the croatian geological survey through programme funding provided by the croatian ministry of science and education. we would like to thank colleagues from the institute for quaternary palaeontology and geology of the croatian academy of sciences and arts and the employees of public institution “mljet national park” for their help during excavations. dragica kovačić from the croatian geological survey is also thanked for laboratory assistance, and mateo petrović from the institute for quaternary palaeontology and geology of the croatian academy of sciences and art for editing the plan and photos. we also thank maja andrič and other reviewers for constructive comments that improved this paper. funding some parts of this research were funded by the foundation of croatian academy of sciences and arts (grant number 53114/2022), and by the internal research project „zg-lab“ at the croatian geological survey, funded by the national recovery and resilience plan 2021–2026 of the european union – nextgenerationeu, monitored by the ministry of science and education of the republic of croatia. references baize, d. & girard, m.c. (2009): référentiel pédologique.– afes, versailles, 405 p. bass, b. (2008): early neolithic communities in southern dalmatia: farming seafarers or seafaring farmers?– eur. j. archaeol., 11/2–3, 245–265. doi: 10.1177/1461957109106376 beug, j-h. (1967): on the forest history of the dalmatian coast.– rev. palaeobotan. palynol., 2, 271–279. doi: 10.1016/0034-6667(67)90156-x beug, j.-h. (2015): leitfaden der pollenbestimmung für mitteleuropa und angrenzende gebiete.– verlag dr. friedrich pfeil, münchen, 542 p. bognar, a. (1999): geomorfološka regionalizacija hrvatske.– acta geographica croatica, 34, 7–26. coles, g. m., gilbertson, d. d., hunt, c. o. & jenkinson, r. d. s. (1989): taphonomy and the palynology of cave deposits.– cave science, 16/3, 83–89. connor, s.e., thomas, i., kvavadze, e.v., arabuli, g.j., avakov, h.s. & sagona, a. (2004): a survey of modern pollen and vegetation along an altitudig eo lo gi a c ro at ic a geologia croatica 77/138 nal transect in southern georgia, caucasus region.– rev. palaeobot. palynol., 129, 229–250. doi: 10.1016/j.revpalbo.2004.02.003 d’agostino, a., di marco, g., marvelli, s., marchesini, m., martínezlabarga, j.m., rolfo, m.f., canini, a. & gismondi, a. (2022): pollen record of the late pleistocene–holocene stratigraphic sequence and current plant biodiversity from grotta mora cavorso (simbruini mountains, central italy).– ecol. evol., 12, 1–16 (e9486). doi: 10.1002/ece3.9486 doláková, n. (2014): palynological analysis of sediment from za hájovnou cave.– acta musei nationalis pragae, series b – historia naturalis, 70/1–2, 35–42. doi: 10.14446/amnp.2014.35 estiarte, m., peñuelas, j., lópez-martínez, c. & pérez-obiol, r. (2008): holocene palaeoenvironment in a former coastal lagoon of the arid south eastern iberian peninsula: salinization effects on δ15n.– veg. hist. archaeobot., 17, 667–674. doi:10.1007/s00334-008-0153-y. florenzano, a., mercuri, a.m., rinaldi, r., rattighieri, e., fornaciari, r., messora, r. & arru, l. (2017): the representativeness of olea pollen from olive groves and the late holocene landscape reconstruction in central mediterranean.– front. earth sci., 5, 85–96. doi: 10.3389/feart.2017.00085 fyfe, r., woodbridge, j. & roberts, c.n. (2018): trajectories of change in mediterranean holocene vegetation through classification of pollen data.– veg. hist. archaeobot., 27, 351–364. doi: 10.1007/s00334-017-0657-4 hammer, ø., harper, d.a.t. & ryan, p.d. (2001): past: palaeontological statistics software package for education and data analysis.– palaeontol. electron., 4/1, 9 p. havinga, a.j. (1964): investigation into the differential corrosion susceptibility of pollen and spores.– pollen et spores, 6, 621–635. hunt, c.o. & fiacconi, m. (2018): pollen taphonomy of cave sediments: what does the pollen record in caves tell us about external environments and how do we assess its reliability?– quat. int., 485, 68–75. doi: 10.1016/j.quaint.2017.05.016 husinec, a. (2002): stratigrafija mezozojskih naslaga otoka mljeta u okviru geodinamske evolucije južnog dijela jadranske karbonatne platforme [mesozoic stratigraphy of the island of mljet within the geodynamic evolution of the southern part of the adriatic carbonate platform – in croatian, with an english abstract].– unpubl. phd thesis, faculty of science, university of zagreb, 300 p. iuss working group wrb (2007): world reference base for soil resources 2006. world soil resources reports no. 103. fao, rome, 128 p. izdebski, a., słoczyński, t., bonnier, a., koloch, g. & kouli, k. (2020): landscape change and trade in ancient greece: evidence from pollen data.– econ. j., 130/632, 2596–2618. doi: 10.1093/ej/ueaa026 jahns, s. (2002): an improved time scale for the holocene history of vegetation and environment on the south dalmatian island of mljet.– veget. hist. archaeobot., 11, 315–316. doi: 10.1007/s003340200043 jahns, s. & van den bogaard, c. (1998): new palynological and tephrostratigraphical investigations of two salt lagoons on the island of mljet, south dalmatia, croatia.– veget. hist. archaeobot., 7, 219–234. doi: 10.1007/bf01146195 kapp, r.o., davis, o.k. & king, j.e. (2000): guide to pollen and spore, 2nd ed.– american association of stratigraphic palynologist foundation, dallas, 279 p. kurečić, t., bočić, n., wacha, l., bakrač, k., grizelj, a., tresić pavičić, d., lüthgens, c., sironić, a., radović, s., redovniković, l. & fiebig, m. (2021): changes in cave sedimentation mechanisms during the late quaternary: an example from the lower cerovačka cave, croatia.– front. earth sci., 9, 1–26 (672229), doi: 10.3389/feart.2021.672229 leroy, s.a.g., marret, f., gibert, e., chalié, f., reyss, j.-l. & arpe, k. (2007): river inflow and salinity changes in the caspian sea during the last 5500 years.– quat. sci. rev., 26, 3359–3383. doi: 10.1016/j.quascirev.2007.09.012 maher, l.j. (1981): statistics for microfossil concentration measurements employing samples spiked with marker grains.– rev. palaeobot. palynol., 32, 153–191. doi: 10.1016/0034-6667(81)90002-6 mauch lenardić, j., oros sršen, a. & radović, s. (2017): holocene faunal remains from spila nad procjepom cave (island of mljet): preliminary results and future investigations.– in: marjanac, lj. (ed.): 5th regional scientific meeting on quaternary geology dedicated to geohazards and final conference of the loladria project “submerged pleistocene landscapes of the adriatic sea”, 49–49 p. mendonça filho, j.g., menezes, t.r. & mendonça, j.o. (2017): chapter 18: palynofacies trends and parameters.– in: filho, j.g. & borrego, a.g. (ed.): iccp training course on dispersed organic matter, integrating transmitted and reflected light microscopy, gfz, potsdam, 187–207 p. mesić, z., peternel, h., kušan, v., križan, j., antonić, o., matočec, n., pasarić, a., hruševar, d., grgurić, z. & bajica, m. (2009): priručnik o kartama staništa dalmacije. prioritetna područja: otok pag, estuarij krke, otok vis i pučinski otoci, otok mljet [handbook on habitat maps of dalmatia priority areas: the island of pag, the krka estuary, the island of vis and offshore islands, the island of mljet – in croatian].– institute of applied ecology, zagreb, 126 p. moore, p.d., webb, j.a. & collinson, m. (1991): pollen analysis, 2nd ed.– blackwell science, oxford, 216 p. navarro, c., carrion, j.s., munuera, m. & prieto, a.r. (2001): cave surface and the palynological potential of karstic cave sediments in palaecology.– rev. palaeobotan. palynol., 117/4, 245–265. doi: 10.1016/s0034-6667(01)00095-1 noël, h., garbolino, e., brauer, a., lallier-vergès, e., de beaulieu, j.l. & disnar, j.r. (2001): human impact and soil erosion during the last 5000 yrs as recorded in lacustrine sedimentary organic matter at lac d’annecy, the french alps.– j. paleolimnol., 25, 229–244. doi: 10.1023/a:1008134517923 oros sršen, a., bajo, p., radović, s., petrović, m., perkić, d. & mauch lenardić, j. (2017): quaternary deposits of spila nad procjepom cave (mljet).– in: krklec, c. (ed.): man and karst. university of zadar, 59 p. oros sršen, a., petrović, m., radović, s., perkić, d. & mauch lenardić, j. (2013): spila nad procjepom (mljet) – pogled u prošlost.– in: anonymous (ed.): program, događaji i sažeci: skup speleologa hrvatske s međunarodnim sudjelovanjem buje 2013 raduno degli speleologi della croazia con partecipazione internazionale buie 2013, momjan, croatia, november 22–24, speleološko društvo buje, 20–21. regula-bevilacqua, lj. & ilijanić, lj. (1984): analysis of the flora of the island of mljet.– acta bot. croat., 43/1, 119–142. reimer, p.j., austin, w.e., bard, e., bayliss, a., blackwell, p.g., bronk ramsey, c., butzin, m., cheng, h., edwards, r.l., friedrich, m., grootes, p.m., guilderson, t.p., hajdas, i., heaton, t.j., hogg, a.g., hughen, k.a., kromer, b., manning, s.w., muscheler, r., palmer, j.g., pearson, c.l., van der plicht, j., reimer, r.w., richards, d.a., scott, e.m., southon, j.r., turney, c.s., wacker, l., adolphi, f., büntgen, u., capano, m., fahrni, s.m., fogtmann-schulz, a., friedrich, r., köhler, p., kudsk, s.g., miyake, f., olsen, j., reinig, f., sakamoto, m., sookdeo, a. & talamo, s. (2020): the intcal20 northern hemisphere radiocarbon age calibration curve (0–55 cal kbp).– radiocarbon, 62, 725–757. doi: 10.1017/rdc.2020.41 schenk, f., väliranta, m., muschitiello, f., tarasov, l., heikkilä, m., björck, s., brandefelt, j., johansson, a.v., näslund, j.o. & wohlfarth, b. (2018): warm summers during the younger dryas cold reversal.– nat. commun., 9/1634. doi:10.1038/s41467-018-04071-5 sebag, d., copard, y., di-giovanni, c., durand, a., laignel, b., ogier, s. & lallier-vergès, e. (2006a): palynofacies as useful tool to study origins and transfers of particulate organic matter in recent terrestrial environments: synopsis and prospects.– earth sci. rev., 79/3–4, 241–259. doi: 10.1016/j.earscirev.2006.07.005 sebag, d., di-giovanni, c., ogier, s., mesnage, v., laggoun-défarge, f. & durand, a. (2006b): inventory of sedimentary organic matter in modern wetland (marais vernier, normandy, france) as source indicative tools to study holocene alluvial deposits (lower seine valley, france).– int. j. coal. geol., 67, 1–16. doi: 10.1016/j.coal.2005.08.002 suc, j.-p., popescu, s.-m., fauquette, s., bessedik, m., jiménez-moreno, g., bachiri taoufiq, n., zheng, z., médail, f. & klotz, s. (2018): reconstruction of mediterranean flora, vegetation and climate for the last 23 million years based on an extensive pollen dataset.– ecol. mediterr., 44/2, 53–85. doi:10.3406/ecmed.2018.2044 šegota, t. & filipčić, a. (2003): köppen’s classification of climates and the problem of corresponding croatian terminology.– geoadria, 8/1, 17–37. doi: 10.15291/geoadria.93 španjol, ž., rosavec, r., vučetić, m., nodilo, j. & gašparović, i. (2016): contribution to the natural regeneration of forests in the mljet national park after the fire.– vatrogastvo i upravljanje požarima, 6/2, 6–58. šumberová, k. (2011): typhetum latifoliae nowiński 1930.– in: chytrý, m. (ed.): vegetace české republiky. 3. vodní a mokřadní vegetace [vegetation of the czech republic 3. aquatic and wetland vegetation – in czech]. academia, praha, 401–405 p. trinajstić, i. (1998): plantgeographical division of climazonal forest vegetation of croatia.– šumarski list, 9–10, 407–421. tyson, r.v. (1993): chapter 5: palynofacies analysis.– in: jenkins, d.g. (ed.): applied micropaleontology.– kluwer academic publishers, amsterdam, 153–191 p. tyson, r.v. (1995): sedimentary organic matter. organic facies and palynofacies.– chapman and hall, london, 615 p. ugarković, d., španjol, ž., tikvić, i., kapučija, d. & plišo vusić, i. (2019): microclimate differences in the degradation stages of holm oak (quercus ilex l.) forests.– šumarski list, 9–10, 391–402. doi: 10.31298/sl.143.9-10.1 van de schootbrugge, b., koutsodendris, a., taylor, w.a., weston, f., wellman, c.h. & strother, p.k. (2024): recognition of an extended record of euglenoid cysts: implications for the end-triassic mass extinction.– rev. palaeobotan. palynol., 105043. doi: 10.1016/j.revpalbo.2023.105043 volarić-mršić, i. (1984): survey of vegetation and aerobiological research on the island of mljet.– acta bot. croat., 43, 143–159. whitlock, c. & larsen, c. (2001): charcoal as a fire proxy.– in: smol, j.p., birks, j.b. & last, w.m. (eds.): tracking environmental change using lake sediments: terrestrial, algal, and siliceous indicators (volume 3). kluwer academic publishers, dordrecht, 75–97 p. doi: 10.1007/0-306-47668-1_5 g eologia c roatica bakrač et al.: first palynological results from spila nad procjepom cave, mljet island (croatia) 39 sample sp 22 p1 sp 22 p2 sp 22 p3 w o o d y p h yt o cl a st s brown-black biostructured wood 51 21 25 translucent, yellow-green plant tissue 7 6 1 degraded wood (ap) 110 44 113 degraded wood (gp) 196 173 125 corroded charcoal 9 87 125 lath-shaped charcoal 2 6 39 equant-shaped charcoal 5 14 12 charcoal 16 107 176 preserved phytoclasts 58 27 26 transformed phytoclasts 322 324 414 total phytoclasts 380 351 440 aom 4 0 2 pa ly n o m o rp h s bisaccate pollen 1 3 1 angiosperm pollen 7 21 3 spores 6 10 3 freshwater algae 1 6 0 total 399 391 449 lycopodium batch 280821291 3 11 3 om “concentration” (particles / g) 120791 53254 155923 sample sp 22 p1 sp 22 p2 sp 22 p3 spore 9 18 24 7.0% 11.8% 20.7% pinus subgenus pinus (diploxylon) 24 15 16 18.5% 9.8% 13.9% oleaceae 24 34 27 18.5% 22.2% 23.2% ericaceae 6 17 2 4.8% 11.2% 1.7% ostrya 1 0 0 0.8% 0.0% 0.0% quercus 1 0 0 0.8% 0.0% 0.0% acer 1 0 0 0.8% 0.0% 0.0% celastraceae 0 1 0 0.0% 0.7% 0.0% ephedra 0 1 0 0.0% 0.6% 0.0% cyperaceae 0 0 3 0.0% 0.0% 2.6% poaceae 11 9 8 8.5% 5.9% 6.9% chenopodiaceae 2 0 0 1.6% 0.0% 0.0% asteraceae 15 17 6 11.7% 11.9% 5.2% artemisia 2 0 0 1.5% 0.0% 0.0% cichoriaceae 17 24 14 13.2% 15.7% 12.2% caryophyllaceae 4 3 1 3.2% 1.9% 0.8% solanaceae 1 0 0 0.8% 0.0% 0.0% lamiaceae 1 0 1 0.8% 0.0% 0.8% valeriana 2 3 3 1.5% 1.9% 2.6% typha latifolia 2 4 2 1.5% 2.6% 1.7% liliaceae 0 0 2 0.0% 0.0% 1.7% alismataceae 0 0 1 0.0% 0.0% 0.8% undiff. 6 7 6 4.5% 4.6% 5.2% pseudoschizaea 1 1 0 redeposit pollen 5 20 2 modern polypodiaceae 10 22 35 ex. lycopodium 50 96 120 mass (g) 30.00 18.37 26.30 ls (18584) 2 2 2 pollen sum 129 153 116 concentration 3196 3225 1366 total sum of pollen and spores 129 153 116 sum of arboreal pollen 55 67 45 42.6% 43.8% 38.8% sum of non-arboreal pollen 57 61 41 44.2% 39.8% 35.3% sum of spores 9 18 24 7.0% 11.8% 20.7% supplement 1. palynofacies supplement 2. the content of palynomorphs 2021 | 74/2 | 139–151 | 14 figs. | 3 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the research on karst depressions (dolines, uvalas, poljes) has a long tradition in karst geomorphology (cvijić, 1893; cramer, 1941; sweeting, 1972; bögli, 1980; jennings, 1985; white, 1988; gams, 1994; mihljević, 1994; šušteršič, 1994; čar, 2001; sauro, 2003; ćalić, 2011; pahernik, 2012 etc.). less commonly, a geomorphological investigation has focused on linear features on karst (milojević, 1955; monroe, 1964; roglić, 1964; brook & ford, 1978; day, 1983; faivre, 1994; hevesi, 2001; tîrlӑ & vijulie, 2013; bočić et al., 2015; harmand et al., 2017 etc.). the occurrence of linear, dry valley-like features on the karst surface of krk island was first introduced in the study published by benac et al. linear features on karst surfaces: an example from krk island ela šegina1, čedomir benac2, france šušteršič3, martin knez4,5,6 and jože čar7 1 geological survey of slovenia, dimičeva 14, 1000 ljubljana, slovenia; (ela.segina@geo-zs.si) 2 university of rijeka, faculty of civil engineering, radmile matejčić 3, 51000 rijeka, croatia 3 laze 22, 1370 logatec, slovenia 4 research centre of the slovenian academy of sciences and arts, karst research institute, titov trg 2, 6230 postojna, slovenia 5 unesco chair on karst education, university of nova gorica, glavni trg 8, 5271 vipava, slovenia 6 yunnan university international joint research center for karstology, xueyun rd. 5, 650223 kunming, china 7 beblerjeva ulica 4, 5280 idrija, slovenia doi: 10.4154/gc.2021.13 abstract krk island located in the dinaric karst is characterized by somewhat contradictory, yet undefined depressions of linear geometry. a comprehensive spatial analysis considering over 900 linear features served as a testing ground for revealing the specific circumstances required for the occurrence of the linear morphology on the surface of rather pure karst typically characterized by dolines. morphological characteristics, spatial distribution and field evidence imply that linear features of different appearance are the outcome of several different mechanisms including speleogenesis and denudation, slope processes and erosion by the torrential surface runoff. surface runoff occurred due to specific regional geological, morphological and climate conditions in the area. recently, such linear features exhibit a dry valleyor dry gorge-like appearance. this example from the dinarides provides insight into the possible circumstances that may cause a temporal surface runoff even in rather pure karst conditions. this knowledge is valuable for understanding other karst areas expressing temporal surface runoff or imprints of its past occurrences. (2013) (figure 1). they noticed that the karst surface is populated strictly by dolines or strictly by linear features so that they spatially do not coincide. some linear features indicated the operation of surface runoff, raising a question of the pre-karstic fluvial inheritance on a recent karst surface, as determined in some other karst areas (warwick 1964; bočić 2003). based on allochthonous fluvial sediments found on the karst surface, a similar presumption was also made for the area of kras in the northern part of the dinaric karst (radinja, 1985). however, given the discovery of unroofed caves at that site, the allochthonous fluvial sediments were proven to have an underground fluvial, rather than a surface fluvial origin (mihevc, 2007). this example shows the complexity of the linear phenomena in karst conditions. linear features dissecting the karst surface are common features along the coastal side of the dinaric mountains and were also evidenced elsewhere (lončar, 2009). however, their existence in rather pure karst conditions, where the karst surface is typically characterized by circular depressions (dolines) (šušteršič, 1982, 1996), has not previously been the subject of extensive scientific discussion. this paper presents the first systematic evidence and basic morphological and distributive characteristics of linear features occurring in close proximity to pure karst conditions. it aims to present the phenomenon of line ar features on the karst surface and provoke further discussion on the topic of linearity in karst geomorphology. 2. study area krk island occupies an area of 405.75 km² (statistički godišnjak, 2018), located in the north-eastern adriatic sea between the istrian peninsula and the vinodol coast. together with some neighbouring islands it constitutes the kvarner area (figure 2). the island has variable morphology, with the north article history: manuscript received july 13, 2020 revised manuscript accepted april 12, 2021 available online june 30, 2021 keywords: karst geomorphology, spatial analysis, gis, dinaric karst, adriatic sea, dry karst valley, linear feature figure 1. an example of linear features on the bare karst surface of krk island. (photo: ž. gržančić) g eo lo gi a c ro at ic a geologia croatica 74/2140 being characterized by rather flat lowlands, mainly between 5 and 45 m a.s.l. the central part has a gently undulating hilly surface with slope inclinations < 4° and low elevation differences. to the south-east, lowlands gradually pass to a karst plateau with an elevation of approximately 240–360 m, bordered by steep rocky slopes exceeding 30°. this part is characterized by high terrain ruggedness. the highest peak reaches an elevation of 568 m ( fi gure 2). krk island and the kvarner area are enclosed by the high mountain ranges of učka (1,400 m) in the west and north velebit mt. (1,600 m) to the east. as a result, the area is influenced by both mediterranean and continental climates and characterized by intrusions of cold air during the winter and convective precipitation in the summer. these specific conditions result in the lack of a distinct dry period typical of the mediterranean climate (šegota & filipčić, 2003). mean annual precipitation on krk island is 1,100–1,500 mm (for the period 1961–1990) (source: croatian meteorlogical and hydrological service). the amount of precipitation decreases from east to west, reaching a peak in the elevated areas in the central and southern parts of krk island. the mean annual air temperature on krk island is 11°–15°c (for the period 1961–1990) (source: croatian meteorlogical and hydrological service). induced by the influence of the mediterranean sea, the entire kvarner area has considerably higher temperatures compared to the continent. the mean annual temperature on krk island is directly influenced by the elevation with the lowest temperatures occurring in the hilly central and mountainous southern part. generally, krk island is, as well as the wider kvarner area, characterized by the mixing influences of the mediterranean airtemperature conditions and continental precipitation regime. the most important local factors causing modifications of the climate are the topography of the nearby dinaric mountain range with its altitude and position according to the prevalent air-mass circulation, and the adriatic sea (dhmz, 2008). within the island, the topography and the distance from the dinaric mountains are the most important factors for micro-climate modifications. the area consists mainly of cretaceous carbonate rocks (figure 3). the outcrops of lower cretaceous (albian) limestone (92 to 97% caco3) and dolomitic limestone (70% caco3) in the western and south-western parts of the island form the cores of large anticlines. albian–cenomanian dolomites and diagenetic breccias (26–73% caco3) outcrop in relatively narrow zones. cenomanian–senonian rudist limestones (98–99% caco3) occur over a wide area (mamužić et al., 1969; šikić et al., 1969; šušnjar et al., 1970; benac et al., 2013). all outcropping carbonates are characterized by their rather uniform nature and high purity (figure 3). palaeogene carbonate and siliciclastic rocks predominantly fill the main syncline of the island, but short and narrow stretches are also observed related to other minor synclines. small outcrops appear in isolated zones over the entire area. they are preserved within the larger karst depressions or are compressed within local tectonic structures (šegina, 2021). siliciclastic rocks consist of marls in the lower zone and flysch (siltstone with interbeds of sandstone) towards the sucession top (mamužić et al., 1969; šikić et al., 1969; šušnjar et al., 1970; benac et al., 2013). oligocene–miocene carbonate breccias overlie cretaceous and palaeogene rocks in the south-western part of the island. the floors of a few large depressions are covered by the quaternary figure 2. location and morphology of krk island. g eologia c roatica šegina et al.: linear features on karst surfaces: an example from krk island 141 deposits (benac et al., 2013). the central and western parts of krk island are covered by younger thick sediments (a mix of older terra rossa, weathered flysch and loess) (benac & durn, 1997; šegina, 2021). during most of the mesozoic era, the area of krk island was part of a carbonate platform. the shallow-water marine sedimentation on the platform was mainly monotonous until the middle cenomanian), resulting in a several km thick carbonate sequence. in the upper cretaceous, tectonic movements caused the disintegration of the carbonate platform with the simultaneous uplift of some platform parts and subsidence of others (vlahović et al., 2005). parts of the kvarner area, including the area of krk island, probably emerged and remained under terrestrial conditions from the cenomanian until the start of the palaeogene transgression (vlahović et al., 2005). the palaeogene transgression started with the sedimentation of foraminiferal limestones, and later marls and flysch that probably covered most of the northwestern part of the present adriatic region (marinčić, 1981). this transgression interrupted the process of karstification on the present-day territory of krk island (benac et al., 2013). during the eocene, wide basins were formed under the influence of regional ne-sw oriented compression (mather, 2009). uplift and re-working of the sedimentary masses originating from the internal dinarides provided sources of clastic deposits that were deposited in such basins during the palaeocene and eocene (korbar, 2009). similar compression (wnw– ese) also influenced the area of krk island (benac et al., 2013). from the eocene to the pliocene, the regional principal compression stress oriented ne–sw caused the formation of wide basins where sedimentation of siliciclastic deposits (flysch) occurred. this phase finished with strong orogenic movements that formed the dinarides and structures with a dinaric strike (nw– se) that are the main tectonic features on krk island (jamičić et al., 1995). in the upper pliocene, the dominant nw–se strike was disturbed by younger diagonal and transverse strike-slip faults during the pliocene and quaternary under the influence of the re-oriented neotectonic regional compression oriented n–s (žibret & vrabec, 2016). recently, the area is subject to transpression and radial extension in the vinodol valley located northeast of krk island (palenik et al., 2019). retrograde structure rotation in the youngest tectonically active period reflects in the present-day relief guided by the nnw–sse-oriented structures in the northern and central and nw–se in its southeastern part of krk island (mihljević, 1994). 3. methods the entire surface formed in the carbonate rock mass of krk island (380 km²) was inspected to create a complete dataset of linear features and to analyse their basic morphometric characteristics and distribution. linear features were evidenced with a combination of two data sources: ortho-rectified aerial photos (digital orthophoto or dof) at a resolution of 0.5 m/pixel obtained in 20041 (figure 4 a) and a topographical map at scale 1:5,000 with 5 m 1 state geodetic administration of the republic of croatia: https://dgu.gov.hr/ (july 2020) figure 3. geology of krk island. (source: mamužić et al., 1969; šikić et al., 1969; šušnjar et al., 1970). complexometric analysis of lithostratigraphic units was performed in the chemical analytical laboratory of the zrc sazu karst research institute. see šegina (2021) for details on methodology. g eo lo gi a c ro at ic a geologia croatica 74/2142 interval contour lines created between 1954 and 20102 (figure 4 b). the resulting dataset was vectorized manually and verified by several field campaigns between 2014 and 2020. see šegina (2021) for discussion on the subjectivity of the manual extraction of morphological features from dof and topographic maps. geological characteristics, such as lithological and tectonic elements, were acquired from the only available data source, i.e. the basic geological map (mamužić et al., 1969; šikić et al., 1969; šušnjar et al., 1970). due to its low resolution (1:100,000), only the main geological structures could be analysed in relation to the linear features. to capture all the morphological variation of the linear features, the criteria for their detection were set very wide. all depressions with an elongated geometry, detectable using the aforementioned data sources were considered as linear features, irrespective of their depth, length, gradient, or any other morphological characteristic. the linearity has been considered as topographical one-dimensionality and not as rectilinearity. the course of the linear surface features was delineated by the combination of topographic map and dof. it followed the contour curving on a topographic map (figure 4 a) and thicker soil accumulations, change in vegetation and shadow effect on dof (figure 4 b). 2 state geodetic administration of the republic of croatia: https://dgu.gov.hr/ (july 2020) figure 4. visibility of linear features on a – topographic map, b – dof. table 1. basic statistics of the measured parameters for linear features on krk island. n of features total length (m) min. (m) max. (m) mean (m) 941 691 23 26 735 table 2. list of spatial analyses performed on a dataset of linear features. parameter method procedure the density of linear features line density (arcpro 2.5.0) calculating the density of linear features in the neighbourhood of each output raster cell in length per unit of area at 1000 m search radius. length measurement measurement of a complete feature’s length. meandering inverse sinuosity index the ratio between the curvilinear length and the euclidean distance between the endpoints of the linear feature. branching modified strahler-horton stream number (strahler, 1952; horton, 1945) assigning the highest numeric order within the drainage network to the entire drainage basin. gradient measurement a ratio between the vertical distance between endpoints of a linear feature and the length of the feature. orientation measurement orientation measurement of an individual linear feature’s segment. drainage pattern obtained visually from the ground view of linear features assigning a type of channel network geometry, namely parallel, centripetal, rectangle, dendritic or no pattern (after summerfield, 1991). linear profile measurement measurement of linear feature’s floor altitude along the main trench. a total of 941 linear features were evidenced on krk island with a total length of 691 km (table 1). an entity was defined as a compound feature of linked linear segments. the features hard to determine by the remote methods were examined in the field. linear features were also field-checked for potential evidence of past or recent surface runoff. for quantitative characterisation and classification, the entire dataset of linear features was subject to spatial analysis including several morphometric and distributive parameters typically used in fluvial geomorphology (table 2). spatial analysis was performed with arcpro software employing an equal interval classification. all the listed spatial analyses were performed on the entire dataset, except for the longitudinal profiles. they were acquired manually by the digitization of the topographic map at the scale of 1:5,000 due to the limitations of an available low-quality digital terrain model (dtm). the examples were selected randomly in a manner to cover the different parts of the study site and to include different morphologic types of linear features (long, short, simple, branched). their locations are shown in figure 5. g eologia c roatica šegina et al.: linear features on karst surfaces: an example from krk island 143 the density of the linear features was spatially correlated to the selected geomorphological and hydrological factors: elevation, slope, topographic roughness and hydrologic potential (figure 6). elevation and slope were extracted from the dtm interpolated from the topographic map at a scale of 1:25,000 (figure 6 a, b). topographic roughness was acquired with the terrain ruggedness index that sums the change in elevation between a grid cell and its eight neighbour grid cells (riley et al., 1999) (figure 6 c). the hydrological potential was considered as the specific annual discharge and was adopted from oštrić et al. (2010) (figure 6 d). 4. results: basic morphometric and distributive characteristics a general overview of the basic morphometric characteristics implies that the most common morphological appearance of line ar features on karst could be described as short, unbranched and rather straight with a highly uniform gradient and oriented in basically any possible direction (figure 7). linear features were evidenced across the entire carbonate surface. they mostly occur along the rims of large karst depressions, along the limbs of eroded synclines and along the coasts (figure 8). all these areas are characterized by high slope angles (figure 6 b). some evidenced linear features form networks (figure 9 f). mostly, the networks consist of unlinked segments, as in the case of centripetal or parallel patterns, but they also form interconnected networks, as in the case of dendritic and rectangular patterns. linear features forming inter-connected networks mostly occur related to the areas of high elevation, slope angles and hydrological potential (figure 9 f). however, some of them also exist outside such areas, implying that morphological and hydrological figure 5. location of linear features where the longitudinal profile was manually extracted. figure 6. considered geomorphologic and hydrologic factors. g eo lo gi a c ro at ic a geologia croatica 74/2144 factors have the potential to inter-connect the linear features, but are not the only controlling factors of their networking. however, linear features forming complex networks and simple, unbranched linear features are all characterized by rather a similar gradient (figure 9 d). the exceptions are short, unbranched and straight linear features that developed on extremely steep slopes (figure 6 b) as a consequence of the eroded limbs of synclines (figure 3, figure 9 d). field inspection showed that the formation of such linear features is mostly guided by slope processes. in some cases, linear features do not show any linkage to the local drainage base (figure 11 a, linear feature n˚1) or exhibit an atypical longitudinal profile (figure 11 a, linear feature n˚3). this indicates that the mechanism of mass removal is not necessarily related to the processes of surface runoff. figure 7. basic morphometric characteristics of the linear features on krk island. figure 8. the density of linear features. figure 9. spatial distribution of analysed parameters for linear features on krk island. g eologia c roatica šegina et al.: linear features on karst surfaces: an example from krk island 145 another peculiar example of a linear feature is the segmented linear feature occurring on a flat surface and shown in figure 11 d. based on the previously performed geophysical investigations it was concluded that such segmented, shallow, flat, elongated depressions have a speleological origin and are actually the segments of unroofed horizontal (epiphreatic) cave passages (čeru et al., 2018). on the recent karst surface, unroofed horizontal caves commonly appear segmentally, so that denuded parts of a cave channel appear as shallow, elongated depressions, while deeper segments of a cave passage remain underground. they were mostly evidenced on the flat bare karst surface in the south-east of krk island, as their presence in other parts of the study site may be masked by soil and vegetation. despite their underground origin, unroofed caves are a part of the surface morphology. as such, they should be considered as a type of a linear feature occuring on the surface of karst terrains. except for the unroofed horizontal caves occurring on flat surfaces, linear features evidenced on krk island occupy slopes greater than approximately 5° inclination (figure 10 c). this inclination appears to represent the limit for an effective mass removal mechanism in the conditions of the study area, enabling the removal of weathered material and the formation of an elongated depression. considering wide (45˚) and general (n-s, w-e, ne-sw, nw-se) classes, no particular orientation of linear features prevail (figure 7 e). however, if we narrow the classes so as to fit the regional structural conditions, where structures with a dinaric orientation prevail (nnw-sse in the northern part of the study area and nw-se in its southern part) (figure 3), we get a different picture. linear features are oriented mostly ne–sw, i.e. perpendicular to the orientation of the tectonic structures in the southern part of the island, and nnw–sse. i.e. aligned with the main orientation of tectonic structures that occur across the entire island (table 3). orientation of linear features spatially coincides with the orientation of geological structures: ne–sw oriented linear features, as well as nw–se-oriented ones, are located mostly in the southern part of the island, while nnw– sse-oriented features are distributed relatively evenly across the entire island. figure 10. correlations of linear feature density to morphological and hydrological factors. pearson’s coefficient (r) is calculated for all individual data. table 3. the orientation of linear features versus orientation of evidenced tectonic structures. orientation ne-sw nw-se n-s nnw-sse other* the total length of recognizable tectonic structures (km) 4.32 30.35 10.15 104.31 0 % 3 20 7 70 0 the total length of linear features (km) 79.22 43.91 34.44 77.83 455.78 % 12 6 5 11 66 *other orientations than those of evidenced tectonic structures. g eo lo gi a c ro at ic a geologia croatica 74/2146 5. discussion the overview of basic morphometric and distributive characteristics of linear features that were evidenced on the karst surface of krk island gave some insight into this rarely discussed geomorphological element. presented characteristics indicate the high complexity and variability of the formation of this rather common but unusual phenomenon. three mechanisms of surface mass removal that resulted in the formation of linear depressions should be considered in closeto-pure karst conditions: chemical (dissolution), permanent slope processes (on slopes exceeding the stability angle) and periodic torrential surface runoff (when the discharge exceeds the conduit system conductivity). the evidence of unroofed horizontal caves indicates that depressions with linear geometry occurring on the recent karst surface could also be a result of the combined mechanism of speleogenesis followed by karst denudation. however, besides the underground formation of features that recently appear as linear depressions, spatial data show that linear features occur tightly related to slopes (figure 10c). the highest linear feature density occurs in the southern and south-eastern parts of krk island. these areas are characterized by high elevations, higher slope inclinations, topographic ruggedness and hydrologic potential (figure 6). as well, the orientation of linear features strictly follows the aspect of the slope. all this indicates that the formation of the majority of linear features is somehow controlled by the slope gradient, and is of mechanical, rather than a chemical nature. recently, linear features are mostly dry with only temporal and rather brief surface runoff occurring in limited segments. short-term torrential surface runoff is activated strictly after storm related precipitation (faivre et al., 2011). however, clear evidence of palaeosurface runoff was discovered in the field. traces of the surface runoff are limited to the middle and lower parts of large and branched linear features with small patches of siliciclastic sediments in the watershed that remained preserved despite generally effective erosion of the eocene impermeable cover. the efficiency of such erosive processes are supported by the well developed karst morphology (šegina, 2021) and occurrence of unroofed caves in the study area (čeru et al., 2018). due to small and rare remnants of impermeable siliciclastic sediments, the karst conditions on krk island are considered as being close-to-pure. benac et al. (2013) proposed that the formation of linear features on krk island might be correlated to locally thicker cover of the palaeogene impermeable sediments and/or more pronounced compressional tectonics. our results suggest that compressional tectonics contributed to the local preservation of impermeable eocene flysch deposits that collected the storm related rainfall. as a result, temporal and strictly localized surface runoff provoked erosive processes that eventually induced the formation of valleys and canyons. the evidence of past surface runoff configure 11. profiles of linear features, shown in a–d due to different scales. for location see figure 5. g eologia c roatica šegina et al.: linear features on karst surfaces: an example from krk island 147 sists of alluvial sediments on the floor of linear features (figure 12 a), traces of the erosion as pools, smooth rock sculpturing on the floor of the features and eroded talus breccia (figure 12 b, c), and the occurrence of alluvial fans at the mouth of linear features (šmuc et al., 2015) (figure 12 d). traces of palaeosurface runoff imply the existence of a climate regime that was characterized by more extreme precipitation events compared to the present. the main uplift with exhumation in the kvarner area occurred during the major tectonic phase in the oligocene and miocene (korbar, 2009). a lack of the miocene and pliocene marine sediments indicates that krk island could have remained emergent ever since the neogene. this emersion caused denudation of the siliciclastic sediments. its duration has been estimated to be more than 10 ma (babić, 2003). the cooling of the global climate started after the mid-miocene climatic optimum. the beginning of glaciation cycles in the northern hemisphere occurred between the pliocene and pleistocene (2,58 ma b.p.). since then, the climate in the mediterranean changed quite significantly. glacial-interglacial cycles were considerably expressed since the middle and late pleistocene (ionian and tarantian) or 0,78 ma b.p. based on the geomorphological traces of glaciation, it is presumed that northern and central velebit were affected by glaciation at altitudes above 1300 m (bognar et al. 1991; bognar and faivre, 2006). as a consequence, numerous accumulations and erosional occurrences of glacial deposits are situated at altitudes of approximately 900 1400 m. during the glacial maximum (mis 2) on velebit mt., the snow boundary was at least 900 m above recent m.s.l. (velić et al., 2017). evidence of glaciation has been found on the risnjak and snježnik mts. (bognar & prugovečki 1997; žebre & stepišnik, 2016). the dinaride mts. barrier extending along the adriatic coast probably had an important impact on the regional climate. results of palynological analyses of sediments in the lošinj channel show a transition from subtropical to a cooler climate regime during mis 5 (brunović et al., 2020). cold and dry environments with periodic warmer periods were detected in loess and palaeosols in susak island during mis 3 (wacha et al., 2017). according to the palynological analysis (schmidt et al. 2001), the climate during the last glacial maximum at the present cres island coast nearby was comparable to that presently characteristic for altitudes 1,450 above m.s.l. on velebit mt. these very changeable climatic conditions could have had a significant effect on processes on the karst landscape in the wider area: stronger mechanical weathering of the carbonate rock mass in dry and cold periods and more expressive chemical weathering in warmer and humid periods (ford & williams, 2007). traces of eroded talus breccia that filled the floors of some linear features indicate several cycles of climate change with interchanging periods of colluvium deposition and erosion of the lithified deposits by the temporal surface runoff (figure 13). periods characterized by the extreme rain events caused the infiltration-limited surface runoff that occurred on sufficient slopes figure 12. the evidence of surface runoff in some linear features. a – rounded sediments on the floor of a linear feature. b – erosional forms: smoothed rocks. c – eroded quaternary breccias and the sub-angular rock fragments accumulation in the forefront. d – alluvial fan eroded by the sea. (photos: e. šegina) g eo lo gi a c ro at ic a geologia croatica 74/2148 along with weathered tectonic structures. it resulted in effective down-cutting and rock sculpturing by the temporal and localized erosion, and sediment transport of the weathered material (figure 13 b, d). in contrast, periods dominated by karst denudation were characterized by underground water circulation, accumulation of colluvium on the floor of abandoned surface streams, lithification of the colluvium and formation of breccias (figure 13 c). in at least several cycles, infiltration-limited surface runoff along linear features was reactivated, evidenced by the eroded breccias in their floors (figure 13 d). the latest investigation of palaeoclimatic, palaeoenvironmental and archaeological data for the mediterranean sea show considerable sea-level changes since mis 6 (approximately 132 ka b.p.) (benjamin et al., 2017). traces of low standing sea level were found over a wide area of krk island (benac & juračić, 1998). submerged mouths of dry valley-like linear features are visible on the sea bottom down to -20 m (benac et al., 2013). according to the positions of the cave entrances (benac et al., 2008), the karstification processes reached a depth of -50 m into the carbonate rock mass. after the rapid late pleistocene–holocene sea-level rise in the adriatic sea during the last 6,000 years, the area has been subject to sea-level stagnation due to the equilibrium between regional tectonic subsidence and hydro-eustatic emergence (pifigure 13. evolution of linear features reworked by torrential surface runoff. g eologia c roatica šegina et al.: linear features on karst surfaces: an example from krk island 149 razzoli, 2005; surić & juračić, 2010; benjamin et al., 2017; benac et al., 2019). erosional processes were considerably reduced, marine erosion/abrasion increased, and gravelly beaches have formed along the coasts of krk island (figure 14). 6. conclusion two very different karstic landscapes intertwine on krk island: typical doline karst with numerous dolines and areas with a dense network of dry karst valleys. they indicate the complex morphological evolution of this area. transpression and radial extension during the upper pliocene and pleistocene caused deformation of the dominant nw– se strike by the younger diagonal and transverse strike-slip faults and opposite vertical tectonic movements. these tectonics events, together with climate changes and sea-level oscillation caused intense erosion, mixing and accumulation of older terra rossa, weathered siliciclastic rocks and loess. the present morphology of the relief is a consequence of these events. a large dataset of linear features occurring in close-to-pure karst conditions was collected and analysed to expose these somehow contradictory karst phenomena and to highlight their basic morphometric and distributive characteristics. spatial analysis and field evidence indicates that linear features on krk island formed by, or with the combination of speleogenesis-karst denudation, slope processes and torrential surface runoff. the occurrence of surface runoff on a close-to-pure karst surface occurred as a result of the specific regional conditions: (i) geology: patches of impermeable material of different origin (siliciclastic rocks compressed within the tectonic structures, re-sedimentation from the surrounding) (ii) regional climate: intensive precipitation as a consequence of the orographic barrier along the coast of the adriatic sea (iii) regional relief energy: high surface gradient as a consequence of the orogenic uplift of the dinaric mountains. linear features occurring on krk island represent an example of the complex circumstances that enabled the formation of different types of linear features in close-to-pure karst conditions. they stress the complexity of the competition of karst and fluvial processes and represent the possible outcome of the mixing of different influences. the results obtained contribute to a better understanding of the morphological evolution of the dinaric karst. in addition, the presented method of spatial analysis shows great potential in the investigation of karst landscapes in wider areas. this knowledge will be valuable in understanding other karst areas expressing temporal surface runoff or traces of their past occurrence. acknowledgment the research was funded by the fund of donors for postgraduate studies in mathematics and science at the slovenian academy of science and arts, by the slovene human resources and scholarship fund, by the university of nova gorica and by the municipality of domžale. this work was supported in part by the university of rijeka under the project uniri-tehnic-18-97 1232 and geosekva (hrzz ip-2016-06-1854). references babić, lj. (2003): the geological evolution and structure of the island of krk: a review.– in: klepač, k. (ed.): fossil fauna of the island of krk, natural history library, 5. prirodoslovni muzej, rijeka, 1–22. figure 14. a gravelly beach as a result of a palaeoerosional processes and current marine abrasion on south-eastern coast (photo: ž. gržančić). g eo lo gi a c ro at ic a geologia croatica 74/2150 benac, č. & durn, g. (1997): terra rossa in the kvarner area – geomorphological condition of formation.– acta geographi. croat., 32/1, 7–17. benac, č. & juračić, m. (1998): geomorphological indicators of the sea-level changes during upper pleistocene (wuerm) and holocene in the kvarner region.– acta geograph. croat., 33, 27–45. benac, č., gržančić, ž., šišić, s. & ružić, i. (2008): submerged karst phenomena in the kvarner area.– in: proceedings of the 5th int. progeo symp. on conservation of the geological heritage, rab, october, 1–5, 2008, 12–13. benac, č., juračić, m., matičec, d., ružić, i. & pikelj, k. (2013): fluviokarst and classical karst: examples from the dinarics (krk island, northern adriatic, croatia).– geomorphology, 184, 64–73. doi: 10.1016/j.geomorph.2012.11.01 benac, č., bočić, n. & ružić, i. (2019): on the origin of both a recent and submerged tombolo on prvic island in the kvarner area (adriatic sea, croatia).– geol. croat., 72/3, 195–203. doi: 10.4154/gc.2019.14 benjamin, j., rovere, a., fontana, a., furlani, s., vacchi, m., inglis, r.h., galili, e., antonioli, f., sivan, d., miko, s., mourtzas, n., felja, i., meredith-williams, m., goodman-tchernov, b., kolaiti, e., anzidei, m. & gehrels, r. (2017): late quaternary sea-level changes and early human societies in the central and eastern mediterranean basin: an interdisciplinary review.– quaternary int., 449, 29–57. doi: org/10.1016/j. quaint.2017.06.025 bočić, n. (2003): relation between karst and fluviokarst relief on the slunj plateau (croatia).– acta carsologica 32/2, 137–146. doi: 10.3986/ac.v32i2.343 bočić, n., pahernik, m. & mihevc, a. (2015): geomorphological significance of the palaeodrainage network on a karst plateau: the una–korana plateau, dinaric karst, croatia.– geomorphology, 247, 55–65. doi: 10.1016/j.geomorph.2015.01.028 bognar, a., faivre, s. & pavelić, j. (1991): glaciation traces on the north velebit (in croatian).– geografski glasnik, 53, 27–39. bognar, a. & prugovečki, i. (1997): morphological traces of glaciation on the risnjak mountain.– geol. croat., 50, 55–75. bognar, a. & faivre, s. (2006): geomorphological traces of the younger pleistocene glaciations in the central part of the velebit mt.– hrvatski geografski glasnik, 68/2, 19–30. bögli, a. (1980): karst hydrology and physical speleology.– springer-verlag, berlin, 284 p. doi: 10.1007/978-3-642-67669-7 brook, g.a. & ford, d.c. (1978): the origin of labyrinth and tower karst and the climatic conditions necessary for their development.– nature, 275, 493–496. doi: 10.1038/275493a0 cramer, h. (1941): die systematik der karstdolinen [the systematics of karst dolines – in german]. unter berücksichtigung der erdfälle, erdzschlotten und verwandter erscheinungen.– neues jahrbuch für mineralogie, geologie und paläontologie, beilage band, abt. b 85, 293–382. cvijić, j. (1893): der karstphänomen [the karst phenomenon – in german].– geographi. abhan., 5, 217–329. čar, j. (2001): structural bases for shaping of dolines.– acta carsologica, 30/2, 239–256. čeru, t., šegina, e., knez, m., benac, č. & gosar, a. (2018): detecting and characterizing unroofed caves by ground penetrating radar.– geomorphology, 303, 524–539. doi: 10.1016/j.geomorph.2017.11.004 ćalić, j. (2011): karstic uvala revisited: toward a redefinition of the term.– geomorphology, 134/1–2, 32–42. doi: 10.1016/j.geomorph.2011.06.029 day, m.j. (1983): limestone valley system in north central jamaica.– caribb. geogr., 2, 16–33. dhmz (2008): klimatski atlas hrvatske 1961–1990, 1971–2000. [climate atlas of croatia-in croatian].– državni hidrometeorološki zavod, zagreb, 200 p. faivre, s. (1994): strukturno-geomorfološka analiza tipova dolinske mreže sjevernog velebita i senjskog bila [in croatian].– senjski zbornik, 21, 9–24. faivre, s., pahernik, m. & maradin, m. (2011): the gully of potovošća on the island of krk the effects of a short-term rainfall event.– geolog. croat., 64/1, 67–80. doi: 10.4154/gc.2011.07 ford, d. & williams, p.w. (2007): karst hydrogeology and geomorphology.– wiley, chichester, 562 p. doi: 10.1002/9781118684986 gams, i. (1994): types of the poljes in slovenia, their inundations and land use.– acta carsologica, 23, 285–302. harmand, d., adamson, k., rixhon, g., jaillet, s., losson, b., devos, a., hez, g., calvet, m. & audra, p. (2017): relationships between fluvial evolution and karstification related to climatic, tectonic and eustatic forcing in temperate regions.– quaternary sci. rev., 166, 38–56. doi: 10.1016/j.quascirev.2017.02.016 hevesi, a. (2001): about the formation of limestone gorges.– acta geograph. croati., 35, 57–66. horton, r.e. (1945): erosional development of streams and their drainage basins; hydrophysical approach to quantitative geomorphology.– bull. geol. soc. am., 56, 275–370. jamičić, d., prelogović, e. & tomljenović, b. (1995): folding and deformational style in overthrust structures on krk island (croatia).– in: rossmanith, h.p. (ed.): mechanics of jointed and faulted rock. a.a. balkema, rotterdam-brookfield, rotterdam, 359–362. jennings, j.n. (1985): karst geomorphology.– basil blackwell, oxford, 293 p. korbar, t. (2009): orogenic evolution of the external dinarides in the ne adriatic region: a model constrained by tectonostratigraphy of upper cretaceous to paleogene carbonates.– earth-sci. rev., 96/4, 296–312. doi: 10.1016/j.earscirev.2009.07.004 lončar, n. (2009): geomorfološka regionalizacija srednjeg i južnog dijela otoka paga.geomorphologic regionalization of the central and southern parts of pag island.– geoadria, 14/1, 5–25. mamužić, p., milan, a., korolija, b., borović, i. & majcen, ž. (1969): osnovna geološka karta 1:100.000, list rab [basic geological map 1:100.000, rab sheet – in croatian].– institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd. marinčić, s. (1981): eocenski fliš jadranskog pojasa [eocene flysch of adriatic zone – in croatian].– geološki vjesnik, 34, 27–38. mather, a.e. (2009): tectonic setting and landscape development.– in: woodward, j. c. (ed.): the physical geography of the mediterranean. oxford univ. press, oxford, 5–32. mihevc, a. (2007): nove interpretacije fluvialnih sedimentov na krasu [new interpretation of fluvial sediments on karst – in slovenian].– dela, 28, 15–28. mihljević, d. (1994): analysis of spatial characteristics in distribution of sink-holes, as an geomorphological indicator of recent deformations of geologic structures.– acta geograph. croat., 29, 29–36. milojević, s.m. (1955): bogaz [bogaz – in serbian].– zbornik radova instituta za proučavanje krša “jovan cvijić”, 1, 7–21. monroe, w.h. (1964): the zanjón, a solution feature of karst topography in puerto rico.– in: nolan, t. b. (ed.): geological survey research, chapter b. u. s. gov. printing office, washington, 126–129. oštrić, m., horvat, b., lončarić-trinajstić, i., benac, č., ružić, i. & rubinić, j. (2010): research of water resources on karst islands on the example of the island of krk (croatia).– balwois 2010, ohrid, may 25–29, 2010. cd ffp-1835, 1–12. pahernik, m. (2012): prostorna gustoća ponikava na području republike hrvatske [spatial density of dolines in the croatian territory – in croatian].– hrvatski geografski glasnik, 74/2, 5–26. palenik, d., matičec, d., fuček, l., matoš, b., herak, m. & vlahović, i. (2019): geological and structural setting of the vinodol valley (nw adriatic, croatia): insights into its tectonic evolution based on structural investigations.– geol. croat., 72/3, 179–193. doi: 10.4154/gc.2019.13 pirazzoli, p.a. (2005): a review of possible eustatic, isostatic and tectonic contributions in eight late-holocene sea-level histories from the mediterranean area.– quaternary sci. rev., 24, 1989–2001. doi:10.1016/j.quascirev.2004.06.026 radinja, d. (1985): kras v luči fosilne fluvialne akumulacije [karst in the light of the fossil fluvial accumulation – in slovenian].– acta carsologica, 14–15. riley, s.j., degloria, s.d. & elliot, r. (1999): a terrain ruggedness index that quantifies topographic heterogeneity.– int. j. sci., 5/1–4, 23–27. roglić, j. (1964): “karst valleys” in the dinaric karst.– erdkunde, 18, 113–116. sauro, u. (2003): dolines and sinkholes: aspects of evolution and problems of classification.– acta carsologica, 32/2, 41–52. schmidt, r., pugliese, n., mϋller, j., szeroczynska, k., bogner, d., melis, r., kamenik, c., barič, a. & danielopol, d.l. (2001): paleoclimate, vegetation and coastal lake development, from upper pleniglacial until early holocene, in the northern adriatic valun bay (isle of cres, croatia).– ii quaternario, italian j. quaternary sci., 14/1, 61–78. statistički godišnjak (2018): statistički godišnjak republike hrvatske [statistical yearbook of the republic of croatia – in croatian].– državni zavod za statistiku republike hrvatske, zagreb. 588 p. strahler, a.n. (1952): hypsometric (area-altitude) analysis of erosional topography.– geol. soc. am. bull., 63, 1117–1142. doi:10.1130/0016-7606(1952)63 [1117:haaoet]2.0.co;2 summerfield, m.a. (1991): global geomorphology: an introduction to study of landforms.– longmann, burnt mill, 537 p. surić, m. & juračić, m. (2010): late pleistocene–holocene environmental changes records from submerged speleothems along the eastern adriatic coast (croatia).– geol. croat., 63/2, 155–169. doi: 10.4154/gc.2010.13 sweeting, m.m. (1972): karst landforms.– london: macmillan and new york: columbia univ. press, 362 p. doi: 10.1038/269840a0 šegina, e. (2021): spatial analysis in karst geomorphology: an example from krk island, croatia, (springer theses). cham: springer nature, cop. 2021. xvii, 183 p. šegota, t. & filipčić, a. (2003): köppen’s climatic classification and croatian terminology.– geoadria, 8, 17–37. doi: 10.15291/geoadria.93 g eologia c roatica šegina et al.: linear features on karst surfaces: an example from krk island 151 šikić, d., polšak, a. & magaš, n. (1969): osnovna geološka karta 1:100.000, list labin [basic geological map 1:100.000, labin sheet – in croatian].– institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd. šmuc, a., rožič, b., verbovšek, t., gale, l., marjanac t., berčič, t. & popit, t. (2015): alluvial fan deposits near stara baška, krk island, croatia.– in: marjanac, lj. (ed.): abstracts and field guidebook, 4th sci. meeting quaternary geology in croatia and slovenia, zagreb, march 25, 2015, 44–45. šušnjar, m., bukovac, j., nikler, l., crnolatac, i., milan, a., šikić, d., grimani, i., vulić, ž. & blašković, i. (1970): osnovna geološka karta 1:100.000, list crikvenica [basic geological map 1:100.000, crikvenica sheet – in croatian].– institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd. šušteršič, f. (1982): nekaj misli o oblikovanju kraškega površja [some considerations about the spatial organization of the karst terrains – in slovenian, with an english summary].– geografski vestnik, 54, 19–28. šušteršič, f. (1994): classic dolines of classical site.– acta carsologica, 23, 123–152. šušteršič, f. (1996): the pure karst model.– cave and karst science, 23/1, 25–32. tîrlӑ, l. & vijulie, i. (2013): structural–tectonic controls and geomorphology of the karst corridors in alpine limestone ridges: southern carpathians, romania.– geomorphology, 197, 123–136. doi: 10.1016/j.geomorph.2013.05.003 velić, j., velić, i., kljajo, d., protrka, k., škrabić, h. & špoljar, z. (2017): a geological overview of glacial accumulation and erosional occurrences on the velebit and the biokovo mts., croatia.– the mining-geology-petroleum engineering bulletin, 32/4, 77–96. doi: 10.17794/rgn.2017.4.8 vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform: paleogeography, main events and depositional dynamics.– palaeogeography, palaeoclimatology, palaeoecology, 220, 333–360. doi: 10.1016/j.palaeo.2005.01.011 žebre, m. & stepišnik, u. (2016): glaciokarst geomorphology of the northern dinaric alps: snežnik (slovenia) and gorski kotar (croatia).– j. maps, 12/5, 873–881. doi: 10.1080/17445647.2015.1095133 žibret, l. & vrabec, m. (2016): palaeostress and kinematic evolution of the orogen-parallel nw-se striking faults in the nw external dinarides of slovenia unravelled by mesoscale fault-slip data analysis.– geol. croat., 69/3, 295–305. doi:10.4154/gc.2016.30 warwick, t.g. (1964): dry valleys of the southern pennines, england.– erdkunde 18, 116–123. white, w.b. (1988): geomorphology and hydrology of karst terrains.– oxford univ. press, new york-oxford, 464 p. 2023 | 76/2 | 87–103 | 9 figs. | 5 tabs. | 4 suppls. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the pan-european pilot project urge was carried out with the aim of assessing the quality of urban soil through geochemical mapping in different european cities. the main objective of the project was to harmonise the methodology for urban geochemical surveys and to compare the results obtained at european level. the geochemical expert group of eurogeosurveys coordinated the implementation of the whole project, and the croatian geological survey (hgi-cgs) carried out the surveys in the city of sisak, croatia. according to šorša & halamić (2014), the concentration of ptes in the topsoil (0-10 cm) in the city of sisak and its rural surroundings is the result of the geological background and strong anthropogenic influences caused by the long urban, transport, and industrial history of sisak. geochemical mapping of the topsoil in the city of sisak was extended to investigation of the subsoil layers. the aim of the extended investigations was to determine the changes in the concentration of ptes in the soil by depth and to assess the potential risk to human health and the environment. in addition, the geochemical fractions of cr, cu, ni, pb, and zn in the subsurface soil layers were determined using the community reference bureau of reference comparison of urban and rural soils based on speciation of heavy metals by bcr sequential extraction procedure: a case study in the historical and industrial city of sisak, croatia ajka šorša1, goran durn2, anita grizelj1,*, josip halamić1 and lucija prša gazilj3 1 croatian geological survey, sachsova 2, zagreb, croatia; (*corresponding author: agrizelj@hgi-cgs.hr) 2 faculty of mining, geology and petroleum engineering, university of zagreb, pierottijeva 6, zagreb, croatia 3 chalmers university of technology, department of architecture and civil engineering, gothenburg, sweden doi: 10.4154/gc.2023.06 abstract within the framework of the pan-european project “urban geochemistry (urge) in europe – soil, children, health”, pedological and geochemical investigations of the soils of the city of sisak and its adjacent surroundings were carried out, and three urban and two rural soil profiles were examined. the mineralogical composition and concentration of selected potentially toxic elements (ptes) cr, cu, ni, pb and zn in the soil were determined. the community reference bureau of reference (bcr) sequential extraction procedure (sep) of these ptes was undertaken and the potential risk to human health and the environment was assessed. the concentrations of cr and ni are generally similar in urban and rural soil profiles, while the concentrations of cu, pb and zn in soil horizons/layers are higher in urban profiles. the extracted fractions of ptes gave the following general distribution: in urban soil profiles residual (res) > reducible (org) or oxidisable (femn) > exchangeable (carb), except for cu where org > res > femn > carb, while in rural soil profiles res > femn or org > carb, except for pb where femn > res or org > carb. the differences between soils in urban and rural profiles depend mainly on the historical land use, i.e. on the duration and intensity of anthropogenic influences on the soil and, to a lesser extent, on the geogenic origin of the parent material and the pedogenic processes. the studied elements in the urban soil profiles are predominantly of anthropogenic origin, indicating a possible influence of the ancient settlements of segestica and siscia and of heavy industry in the 20th century. the anthropogenic influences on the rural profiles are low and geogenic influences dominate. risks to the environment were assessed in the soil profiles based on pte concentrations in the carb fraction and the sum of the carb, org and femn fractions from bcr sep. all calculated risks to human health and the environment were rated as no-risk, very low risk and low risk. sequential extraction procedure. the exchangeable fraction, the reducible fraction, the oxidisable fraction and the residual were determined by bcr sep in the soil horizons/layers of three urban and two rural soil profiles. in the broadest sense, the term urban soils refers to soils that have developed in urban areas or under strong anthropogenic influence. depending on the objective of a study dealing with urban soils, there are many different definitions of the term (craul, 1992; sobocka, 2003; lehmann & stahr, 2007; pouyat et al., 2010; greinert, 2015; greinert & kostecki, 2019; o’riordan et al., 2021). here, the term “urban soils” is used for all soils in the urban area of sisak, while the term “rural soils” is used for the soils in the adjacent rural area of sisak. the purpose of sep is to study how metals are released into the environment under different environmental conditions. knowing the total concentration of a metal in soil is not sufficient to accurately assess its impact on the environment and its potential contamination. the mobility and bioavailability of a metal are crucial for soil contamination. the sep is a chemical technique that successively extracts metals and other elements from article history: manuscript received march 21, 2023 revised manuscript accepted june 06, 2023 available online june 16, 2023 keywords: sep, potentially toxic elements, soil profiles, anthropogenic influences, risk assessment g eo lo gi a c ro at ic a geologia croatica 76/288 solid samples (soil, sediment, waste) in order of solubility in different geochemical fractions. each successive fraction dissolves a particular phase with metals bound to it and removes them from the system. this method can be used to extract metals sequentially in 2, 3, 4, 5, 6 or 7 fractions. there are several developed methods for sep and the most commonly used are tessier, bcr, short, galán, and geological society of canada (gcs) (zimmerman & weindorf, 2010). the european commission (2001) has proposed the bcr sep method, which differs from the tessier method (tessier et al., 1979) by merging tessier’s first and second fractions i.e., the exchangeable and the carbonate fractions (ure et al., 1993; zimmerman & weindorf, 2010). the aim of developing bcr sep is to compare the results of sep of sediment and soil analysis data at eu level. bcr sep defines three successive extractions of metals from the sample and residual. fraction 1 – carb extracts metal ions adsorbed in the soil and metals bound to carbonates. fraction 2 – femn separates metals bound to iron or manganese oxides that form nodules, concretions, cement between particles or a coating around particles. fraction 3 – org comprises metals bound to organic material and sulphides (tessier et al., 1979; gleyzes et al., 2002). organic matter readily accumulates metals that are degraded under oxidation conditions. the last fraction is residual – res. once the first three fractions are removed, the residue should consist of primary and secondary minerals containing metals in the crystal lattice. these metals are not expected to be released into the environment under conditions prevailing in nature. contaminated soils or soils enriched with ptes pose a potential risk of poisoning some plants, soil microorganisms, animals, and humans. human health can be threatened by contaminated soils in several ways: by inhalation, through the skin, or by consumption of food and drink. a potential environmental risk is defined as the possibility of harming flora, fauna or human health through exposure to high concentrations of harmful elements (rapanat et al., 2008). the potential risk to the environment also depends on the mobility, bioavailability and ecotoxi city of ptes. the risk of poisoning is lower when ptes are fixed in the soil and not mobile. their release into the mobile phase of the soil depends mainly on the eh value, ph and buffer capacity of the soil, then on the content of mn-fe oxyhydroxide, clay and o rganic material in the soil. based on the results of the bcr sep analyses, the risk of a potential mobilisation of ptes into the environment could be assessed. the potential risk of release of ptes into the mobile phase was calculated as a function of the carb fraction (rath et al., 2009; liu et al., 2010) and as a function of the sum of the carb, femn and org fractions (miko et al., 2003). according to the study by šorša (2014) on the distribution of elements in topsoil, their origin and potential risk for the environment and human health, 5 ptes were selected for bcr sep. the first was cr, which is predominantly of geogenic origin, the second was ni, which is partly of geogenic and partly of anthropogenic origin, while the remaining three elements (cu, zn and pb) are predominantly of anthropogenic origin. the objective of the study was to determine any differences in the distribution of these elements by depth in soils in urban and rural soil profiles, their origin in the soil profiles, and the sources of possible contamination. in addition, the risk of release of metals into the environment will be assessed based on the results of the bcr sep. 1.1 study area the city of sisak lies at latitude 45° 29’ n and longitude 16° 20’ e and is located in the posavina region, 57 km south-east of zagreb (fig. 1). the study area includes the urban part of the city and the adjacent rural surroundings. the terrain is lowland. the largest part of the study area lies at an altitude of about 100 m above sea level and the rivers kupa, sava and odra occasionally flood the lower parts of the sisak area. quaternary sediments predominate in the region of the city of sisak. the deposits comfigure 1. geographic location of the study area of sisak, croatia. g eologia c roatica šorša et al.: comparison of urban and rural soils based on speciation of heavy metals by bcr sequential extraction procedure ... 89 prise carbonate alluvium of the river sava in the east, siliciclastic alluvium of the rivers kupa and odra in the west and north, and loess deposits in the central part, within the large meander of the river kupa (fig. 2a; pikija, 1987a, b). based on the pedological map, hydromorphic soils, i.e., the classes of pseudogleyic, undeveloped, semigley and gley soils predominate in the rural surroundings of sisak, and technogenic soils dominate in the urban part (fig. 2b; husnjak, 2012). the climate in sisak is moderately warm and rainy, without extreme dry periods (lisac & herić-nekić, 1995). according to the sisak meteorological station, the most frequent wind directions are ne 15.4% of the time and n 13.0% of the time. in accordance with the official land use in the city of sisak (kaminski-kirš, 2002), the urban soil profiles pr1, pr2 and pr3 are located in the parks and recreation areas, and the rural soil profiles pr4 and pr5 are placed in the area with soils for agricultural production. according to the historical and current land use observed during fieldwork, the urban area of sisak includes “the old urban area; new urban area, industrial area, and partly urban area around the industrial facilities”, while the rural area includes “the predominantly rural area, and mixed area: urban, rural, woods, groves and similar” (fig. 2c). according to the current land use, the urban soil profiles are located in the urban area and the rural soil profiles in the rural area of sisak. the soils of the three urban soil profiles pr1, pr2 and pr3 and the two rural soil profiles pr4 and pr5 are classified according to the wrb (iuss working group wrb, 2014) and the croatian soil classification (csc; husnjak, 2014) and already presented in husnjak et al. (2018) and šorša (2014) (tab. 1). 2. materials and methods 2.1. sampling the locations of the profiles were chosen to achieve an even distribution of soil profiles throughout the study area, consistent with historical and current land use, geological, and pedological characteristics (fig. 2a, b, c; tab. 1). two profiles pr1 and pr2 were located in the old urban area on the terrace sediments of the river kupa and were classified as urbic and linic technosols, respectively. profile pr3 was excavated on the boundary between the new urban area and the partially urban area around the industrial facilities on the loess and classified as a hypereutral regosol. figure 2. a) geological map (pikija, 1987a, b), b) pedological map (husnjak, 2012) and c) the map showing historical and current land use (šorša, 2014) of the study area in sisak with the locations of the soil profiles. table 1. classification of urban and rural soils from profiles in sisak according to the world reference base for soil resources 2014 (iuss working group wrb, 2014) and the croatian soil classification (husnjak, 2014) taken from (husnjak et al., 2018; šorša, 2014). type of soil profile soil profile wrb classification croatian soil classification urban soil profiles pr1 urbic technosols (loamic, calcaric, grossartefactic, humic) humus-accumulative soils; the type rendzina pr2 linic technosol (calcaric, ruptic) technogenic soils; the type deposol pr3 hypereutric regosol (siltic, relocatic, ruptic) over hypereutric relictistagnic retisol (siltic) humus-accumulative soils; the type rendzina rural soil profiles pr4 haplic fluvisol (anthric, calcaric, hypereutric, siltic) hydromorphic soil (semiglay) pr5 haplic fluvisol (anthric, humic, hypereutric, endoarenic) hydromorphic soil (semiglay) g eo lo gi a c ro at ic a geologia croatica 76/290 two profiles were excavated in predominantly rural areas pr4 in the south, on the carbonate alluvium of the sava river, and pr5 in the north on the siliciclastic alluvium of the river kupa and both were classified as haplic fluvisols. the soil profiles in the urban areas (pr1, pr2 and pr3) have only weakly developed horizons and were therefore described and sampled mainly in recognised layers. the urban soil profile pr1 was located in the park in the roman siscia area. the entire profile pr1 is anthropogenic, carbonate, and the soil is black. the profile was dug to a depth of 120 cm and 1 horizon and 5 layers were sampled. the urban soil profile pr2 was taken in the park near the old bridge. the part of the profile to a depth of 105 cm was excavated and then drilled between 105 and 120 cm. the parent material for the soil is mainly of anthropogenic origin. five soil layers were sampled. the urban soil profile pr3 was located in the park in front of the school in caprag. it was dug to 102 cm and the rest was drilled to 200 cm. the settlement of caprag was built in the 50s and 60s of the last century for the workers of the ironworks of sisak. therefore, the upper part of the profile is anthropogenically influenced. six soil samples were collected from four horizons and two layers. the rural soil profiles (pr4 and pr5) have developed horizons. rural soil profile pr4 was located in the south-eastern part of the study area on agricultural land and about 200 m from the river sava. it was dug to a depth of 115 cm and further drilled to 220 cm. six soil samples were collected in six horizons. rural soil profile pr5 is located in the north-western part of the study area, about 1,300 m from the river kupa. soil profile pr5 was only drilled to a depth of 130 cm, and three soil samples were collected. the amount of anthropogenically sourced detritus (bricks, stones, pieces of iron and other material of anthropogenic origin) was often very large in urban areas, so a larger volume of soil weighing up to 4 kg was sampled in urban soil profiles. in soil profiles in rural areas, the weight of the soil samples was about 2.5 kg. twenty-six soil samples were collected from identified soil horizons and layers. 2.2. analyses the samples were air dried at room temperature, gently crushed, sieved through a 2-mm sieve, homogenised, powdered and split for all analyses. the mineralogical composition was determined by x-ray powder diffraction (xrd) in the laboratory of the croatian geological survey. the samples for xrd analyses were ground using a mccrone mill. semi-quantitative xrd analysis was performed using a panalytical vertical x-ray goniometer (type x’pert) equipped with a cu-tube and pw 3018/00 pixcel detector. the experimental conditions were: 45 kv, 40 ma, primary beam divergence 1/4° and continuous scan (step 0.02 °2θ/s). the semi-quantitative composition of the samples was carried out according to the method of schultz (1964). the 5 g of samples for chemical analyses were digested in 90 ml aqua regia, then heated and boiled in a bath (at 95°c) for one hour. after cooling, up to 300 ml of 5% hcl was added to the solution. chemical analyses were performed by inductively coupled plasma mass spectroscopy (icp ms) for a range of 53 chemical elements at acme analytical laboratories, vancouver, canada (the procedure is described in detail in šorša, 2014; šorša et al., 2017). to determine the different forms of metals in soils, a slightly modified three-step procedure described in the report eur 19775 en of the european commission (2001) was used for acid-soluble, reducible and oxidisable soil fractions. what remained after these three steps is the residual fraction (res) which was analysed after the aqua regia treatment (nieuwenhuize et al., 1991). this treatment does not completely dissolve all the remaining mineral phases. the efficiency of the digestion varies from element to element and depends on the mineralogy of the sample material. the result obtained is therefore considered as near-total. the extraction scheme is presented in tab. 2. it should be noted that the results obtained are operationally defined and therefore the significance of the analytical results is related to the extraction scheme used. the sequential extraction scheme recommended by bcr is sufficiently repeatable and reproducible for use in speciation studies (davidson et al., 1994). the resulting solutions were analysed for cr, cu, ni, pb and zn on an aanalyst 700 perkin elmer flame absorption spectrometer (aas) using an air-acetylene flame. the sum of all fractions gave the total metal content of the sample. for statistical purposes analytical data, the value of which was below the dl was assigned half of the dl value. 2.2.1. quality control quality control (qc) for chemical analyses with icp ms was carried out for all topsoil and soil samples from soil profiles collected within the project urge in the sisak study area. the coefficient of variation of the precision of the technique and the accuracy of the standards were satisfactory (the qc is described in detail in šorša, 2014; šorša et al., 2017). soil samples from soil profiles were analysed in geochemical fractions obtained by bcr sep for the five metals cr, cu, ni, pb and zn with the aas. the correlation of the results obtained with both analytical techniques can serve as an additional quali ty control. the comparison of the results can be done by graphical representation or statistical tests such as the t-test or the wilcoxon test (reimann et al., 2008). due to the small number of samples, only a graphical representation of the comparison of the measurement results was made and no statistical tests were performed. comparing the results of the analysis of samples measured with the icp ms with the results of the analysis of the same samples measured with the aas, a slight difference in the measurements can be observed (fig. 3). the concentrations of cr determined with icp ms were higher than those measured with aas for all samples. the results for cu and pb agreed, except in profile pr2 and partly in pr1, where the element contents determined with aas are generally slightly higher than those with icp ms. nickel and zn behave in the same way in the two sets of results. in profiles pr1 and pr2 these metals have higher concentrations when analysed with aas, and their concentrations measured with aas are lower than those determined with icp ms in profiles pr2, pr3 and pr4. table 2. sequential extraction scheme combined with the residual fraction. step reagent soil phase label 1. acetic acid (0.11 mol/l) acid soluble carb 2. hydroxilammonium chloride (0.5 mol/l) reducible femn 3. hydrogen peroxide (8.8 mol/l), followed by extraction with ammonium acetate (1 mol/l) oxidisable org 4. aqua regia (hno3 : hcl = 1:3) residual res g eologia c roatica šorša et al.: comparison of urban and rural soils based on speciation of heavy metals by bcr sequential extraction procedure ... 91 chromium shows the greatest difference in the measurements with aas and icp ms. the reason for this result is the concentration of cr in resistant minerals that are difficult to dissolve in acids (chromite, magnetite, ilmenite). aqua regia was used to dissolve the soil sample before measurement with icp ms and to dissolve the residual fraction for measurement with aas. a slight change in the ratio of hcl: hno3, the temperature or the dissolution time probably led to a deviation in the measurements. the differences in the measurements for cu, ni, pb and zn were small. on average, the differences in the measurements were small and the measured concentrations of the metals showed the same trend of increase or decrease for both analytical techniques. the precision of bcr sep was determined by measuring a soil sample with aas in three consecutive replicates. the accuracy of the results of sep was determined by comparison with a standard sample bcr-701 (tab. 3). certified and measured concentrations of the standard sample bcr-701 for cr, cu, ni, pb and zn by geochemical fractions in soil samples have a large overlap (pueyo et al., 2001). the lowest accuracy was found for cr, probably due to the resistivity of cr minerals. other ptes show generally good accuracy. 2.3. risk assessment the risk to the environment and human health was assessed based on the results of bcr sep in the soil profiles according to risk assessment code (rac) which includes only carb fraction and according to the sum of the concentration of the carb, table 3. quality control for the bcr sep certified and measured concentrations of the standard sample bcr-701 in urban and rural soil profiles. element concentration in standard bcr 701 geochemical fraction carb femn org res sum cr measured 0.75 15.7 136 52.4 205 certified 2.26 45.7 143 62.5 253 cu measured 33.3 80.9 82.0 48.4 245 certified 49.3 124 124 38.5 267 ni measured 11.8 18.8 18.9 41.0 90.5 certified 15.4 26.6 15.3 41.4 98.7 pb measured 5.06 84.6 19.8 39.7 149 certified 3.18 126 9.30 11.0 149 zn measured 154 115 52.6 100 422 certified 205 114 45.7 95.0 460 figure 3. quality control for elements analysed with two analytical techniques by graphic comparison of cr, cu, ni, pb and zn concentration measurements obtained by aas and icp ms. g eo lo gi a c ro at ic a geologia croatica 76/292 femn and org fractions. in both risk assessment methods, the horizons or layers in the soil profiles were treated the same, they were all considered as surface horizons/layers. the potential risk to human health is in urban soil profiles due to land use for recreational purposes and in rural areas due to cultivation of crops for human and animal consumption. in addition, mobilisation of metals in case of contamination in deeper horizons/layers poses a risk to groundwater during the flood season. 2.3.1. risk assessment code the assessment of risk to the environment due to the potential mobilisation of ptes from soil can be based on the metal concentration in the carbonate fraction obtained by the bcr (rath et al., 2009; liu et al., 2010). in the carb fraction, the metals are only weakly bound to the surface of the soil particles or incorporated in the structure of minerals soluble in acids and can be easily mobilised into the environment. the formula for calculating the content of metal in a given fraction is e = (cm /ʃcm) x 100; where (e) is the percentage of metal extraction in the fraction, (cm) is the metal concentration in the fraction, and (ʃcm) is the total metal concentration in the whole sample (ʃcm = carb + femn + org + res) (liu et al., 2010). the risk assessment of metal release to the environment is based on the percentage of extraction (e) of the selected metal in the carb fraction. there is no risk if the e <1%. low, medium, high and very high risk applies to e = 1-10%, e = 11-30%, e = 31-50% and e >50%, respectively (rath et al., 2009). 2.3.2. risk assessment based on the sum of concentrations in the fractions carb, femn and org mesić et al. (2008) proposed legal limits for total metal concentrations in soils according to land use. the proposed classification of land use distinguishes soils for agricultural production, children’s playgrounds, residential areas, parks and recreation areas, and areas for industrial and commercial purposes. the bcr sep of samples from soil profiles revealed four fractions in which the pets cr, cu, ni, pb and zn were bound. metals in res fraction can be mobilised only by strong acids, but such conditions are unlikely in the environment. a realistic assessment of the risk to the environment and human health was obtained by summing the concentration of the first three fractions: carb + femn + org (miko et al., 2003), and comparing these with the prescribed limits for total concentration according to land use. hooker & nathanail (2006) suggested that environmental risk can be expressed as relative risk (rr) for selected elements (i), calculated using the following formula: rri = (total concentration in soil)i / (soil target value) for each land use. 3. results and discussion a soil profile in a naturally developed soil has characteristic horizons that depend, among others, on pedogenesis on a particular parent material, while a soil profile in an urban area usually has no formed horizons, only layers (figs. 4 and 5). in the urban soil profile pr1, the anthropogenic influences are so strong that the soil is a mixture of soil and anthropogenic material. in pr2, the upper layers have been recently disturbed and filled with material brought from elsewhere. soil profile pr3 is under anthropogenic influence in its upper half and shows natural pedogenesis in its lower half. the profiles in the urban area (pr1, pr2 and pr3) have a shallow surface horizon that developed in a relatively short time. it formed in pr1 after the last excavation in 1974, in pr2 the upper layers were backfilled in 2009 and in pr3 during the construction of the caprag settlement in the 1950s and 1960s. soil profiles pr4 and pr5, which are exposed in rural areas, have a natural pedogenic development. their surface horizon is thicker figure 4. urban soil profiles pr1, pr2 and pr3 with their determined horizons/layers. figure 5. rural soil profiles pr4 and pr5 with their determined horizons. g eologia c roatica šorša et al.: comparison of urban and rural soils based on speciation of heavy metals by bcr sequential extraction procedure ... 93 and also developed under anthropogenic influence (ploughing), but is genetically related to the rest of the profile. the influences on the pedogenic development of the soil profiles were multiple. the urban soil profiles pr1 and pr2 are located on the river terrace, pr3 on the slightly elevated loess and the rural profiles pr4 and pr5 in the floodplain. the parent material was brought in by the rivers kupa and sava or by wind, and deposited in their alluvium. the transport and sedimentation were of varying intensity. in addition to the geogenic background, there are numerous anthropogenic influences, which include a long urban history, the construction of dikes for flood protection, the various embankments of streams, ravines and profiles, and industrial development. the pedogenic development of the profiles has been strongly influenced by surface and high-level groundwater. for this reason, mainly hydromorphic soils have developed. in such soils, the migration of ions, colloids and other small particles to the depth of the profile was facilitated. all this has influenced the oscillation and irregularity of the mineralogical composition and the amount of ptes along the horizons/layers in these soils. 3.1. urban soils 3.1.1. mineralogy the following minerals were determined in the samples from the urban soil profiles: quartz, phyllosilicates, calcite, dolomite, plagioclase and cristobalite (fig. 6 and supplements 1; supplements 2). quartz is the predominant mineral in all profiles. besides quartz, phyllosilicates were the most abundant mineral phases in the soil profiles. most of the samples contain 14 å, 10 å and 7 å diffraction maxima that are characteristic of phyllosilicates. the diffraction maxima of 14 å indicates the presence of swelling minerals (smectite and/or vermiculite) and/or chlorite. diffraction maxima of 10 å indicates illitic material, and 7 å indicates the presence of kaolinite and/or chlorite (moore & raynolds,1997; starkey et al., 1984). in sample pr2-ii (15-33 cm) the diffraction maximum of 14 å is not visible. samples pr1iv (70-100 cm) and pr1-v (100-120 cm) do not contain the diffraction maximum of 7 å. the phyllosilicate content is highest in profile pr3. in pr1, the phyllosilicate content is largely uniform over the entire depth. in general, the content of phyllosilicate increases with depth in profiles pr2 and pr3. calcite and dolomite are present in soils of profiles pr1 and pr2, but were not found in pr3. plagioclase is present in pr1, pr2 to a lesser extent than in the soil of pr3, which is probably a consequence of the different parent materials since profiles are located on different sediments (fig. 2a, pikija, 1987a, b) or more intense weathering. a low content of cristobalite was only observed in soil profile pr3. the cristobalite in profile pr3 located on loess (fig. 2a, pikija, 1987a, b) is probably of volcanic origin. as there are several potential cristobalite sources within a relatively short distance of 5 to 15 km from soil profile pr3, the cristobalite may have been deposited together with other loess material. the urban profiles pr1, pr2 and pr3 show anthropogenic influences in their mineralogical composition (fig. 2b, c). profile pr1 has a uniform content of all minerals throughout its depth, which is a consequence of the mixing of materials due to constant digging over. in the layer pr2-ii (15-33 cm), the calcite content is greatly increased and the phyllosilicate content is reduced due to anthropogenic influences. this layer was filled with carbonate sand mixed with the existing parent material. the layer is then covered with nylon and compacted soil to form the surface layer pr2-i (0-15 cm). the lower part of profile pr2 is natural. soil profile pr3 is disturbed to a depth of 67 cm in the upper three layers and therefore contains less phyllosilicates than in the lower three layers, which are natural. the mineralogical composition in the urban soil profiles pr1 and pr2 is consistent with the mineralogical composition of the siliciclastic alluvium of the rivers kupa and odra on which profiles are located (fig. 2a, pikija, 1987a, b). similarly, the mineralogy of profile pr3 also corresponds to the mineralogical composition of loess (fig. 2a, pikija, 1987a, b; šorša et al., 2018). anthropogenic influences are large in profile pr1 and in the upper part of profiles pr2 and pr3. 3.1.2. total concentration of the selected ptes as soil profiles vary according to parent material, pedogenic development, anthropogenic influence and land use (figs. 2a, b, c), there is not even much regularity in the content of selected ptes figure 6. the mineral composition in soil samples in urban and rural soil profiles determined by x-ray diffraction. g eo lo gi a c ro at ic a geologia croatica 76/294 soil profile pr1 has significantly higher levels of ptes: cu, pb and zn than the other profiles (fig. 7; tab. 4). according to the geochemical maps of the spatial distribution of elements on the surface (šorša & halamić, 2014), profile pr1 is located in the area with increased cu and pb concentration. in this profile, the surface horizon is not enriched with ptes, their concen(fig. 7; tab. 4). the surface horizon of soil profiles in urban areas often has elevated levels of contaminants (lehmann & stahr, 2007). the concentration and distribution of selected ptes along the horizons and layers in urban soil profiles pr1, pr2 and pr3 were strongly influenced by human excavation and contamination (fig. 8). figure 7. the concentration of the cr, cu, ni, pb and zn in soil samples in urban and rural soil profiles measured with icp ms. g eologia c roatica šorša et al.: comparison of urban and rural soils based on speciation of heavy metals by bcr sequential extraction procedure ... 95 tration is elevated deeper in the profile. all elements with increased content in the pr1 profile belong to anthropogenic factor 1 (heavy industry), and the element pb also belongs to anthropogenic factor 6 (roman mints) (factors defined by šorša et al., 2017). the concentration of all ptes by layer does not vary significantly, except for the enrichment in the layer at 70-100 cm depth (figs. 4 and 7; tab. 4). in the urban soil profile pr1, ptes have accumulated in the soil over a long period of time. it is located in the park, close to a parcel of archaeological excavations dating back to roman times. the land has been in continuous use for over 2,000 years. it was once the site of the roman siscia, and for the last 150 years (until 1974) it was a cemetery. today it is a city park near industrial facilities. therefore, the amount and distribution of ptes in profile pr1 are mainly of anthropogenic origin (šorša, 2014). copper, pb and zn are elevated due to smelting furnaces and mints in roman times, industry, transport, fossil fuel combustion and other wastes. it is difficult to determine the extent of the influence of cemeteries on ptes concentrations in the profile. in the absence of detailed descriptions of burial methods and the use of coffins, gravestones, etc., one can only speculate on the amount of ptes of “cemetery” origin. in soil profile pr2, the surface horizon is slightly enriched in all elements compared to the underlying horizons (fig. 7; tab. 4). moreover, the concentration of all selected metals, after the previously described drop from the surface layer, increases with depth, with slight variations. the anthropogenic formation of the upper two horizons/layers and the strong influence of the third layer after the flower exhibition in 2009, when the upper two layers were partially filled, had the greatest influence on observed variation in the content of the elements at depth. therefore, the contents of the elements of the surface horizon and the surrounding area cannot be compared. the surface horizon of pr3 is slightly enriched in cu, ni, pb and zn compared to the rest of the profile. this content in the surface horizon is consistent with the geochemical maps of the surrounding area (šorša & halamić, 2014). most of the table 4. the concentration of the cr, cu, ni, pb and zn in soil samples in urban and rural soil profiles measured by aas and icp ms. type ptes cr cu ni pb zn mg/kg soil profile aas icp ms aas icp ms aas icp ms aas icp ms aas icp ms u rb an so il pr ofi le s pr1-a (0-12cm) 18.4 23.0 97.9 93.7 40.6 26.1 144 129 142 124 pr1-i (12-29cm) 18.2 22.0 125 128 40.5 26.7 176 199 147 141 pr1-ii (29-50cm) 17.6 21.0 146 141 40.7 23.4 196 180 159 144 pr1-iii (50-70cm) 18.1 21.0 142 146 37.6 24.6 210 182 148 13 pr1-iv (70-100cm) 17.6 23.0 147 156 41.9 24.1 226 273 150 148 pr1-v (100-120cm) 17.6 21.0 157 149 42.5 22.8 235 191 157 134 pr2-i (0-15cm) 32.6 41.0 52.2 38.8 46.1 28.2 88.2 76.5 197 180 pr2-ii (15-33cm) 12.7 17.0 35.9 25.6 32.7 18.7 47.5 36.1 78.8 68.9 pr2-iii (33-60cm) 13.7 22.0 32.7 17.5 44.6 29.1 34.9 17.9 70.5 58.6 pr2-iv (60-88cm) 27.2 37.0 45.6 30.3 62.2 43.2 64.6 32.6 105 94.2 pr2-v (88-120cm) 22.0 38.0 46.5 31.5 59.0 45.6 46.7 33.5 101 92.8 pr3-a (0-14) 25.5 34.0 25.7 26.2 23.3 30.9 42.8 43.8 139 175 pr3-i (14-28cm) 26.1 35.0 21.4 21.9 23.3 27.6 32.1 34.2 89.2 112 pr3-ii (28-67cm) 29.2 36.0 22.2 22.9 27.1 29.8 19.0 20.7 64.0 86.1 pr3-cg (67-130cm) 30.2 42.0 21.1 22.2 22.7 32.2 11.9 17.2 54.9 73.7 pr3-cg (gr) (130-160cm) 26.6 38.0 20.1 20.7 16.1 20.3 12.2 17.9 32.3 42.2 pr3-cg (160-200cm) 32.5 45.0 24.1 28.0 24.6 30.8 11.8 19.5 40.6 56.0 ru ra l s oi l p ro fil es pr4-p (0-32cm) 21.0 22.0 22.7 19.6 26.1 32.0 19.7 26.2 82.4 91.1 pr4-i/c (32-58cm) 21.0 23.0 21.0 18.4 23.9 31.5 20.9 20.0 50.8 59.9 pr4-ii/c (58-90cm) 26.6 33.0 26.5 27.6 30.9 43.1 26.6 28.3 70.2 83.7 pr4-iii/c/g (90-115cm) 34.1 44.0 27.7 30.9 37.4 53.7 24.1 30.7 84.3 106.6 pr4-iv/c/g (115-160cm) 22.9 25.0 21.4 18.5 30.7 35.1 24.4 18.4 55.1 62.5 pr4-v/c/g (160-200cm) 18.9 20.0 18.2 14.3 27.9 27.5 22.4 14.5 42.5 46.9 pr5-p (0-30cm) 22.7 29.0 20.9 20.7 28.9 30.8 25.4 27.4 63.0 76.4 pr5-g (30-80cm) 22.4 31.0 21.3 21.8 24.3 32.9 13.7 25.8 61.3 77.2 pr5-g (80-120cm) 21.4 30.0 27.9 30.9 30.6 38.1 21.4 24.0 65.6 83.6 figure 8. heatmap of total concentration of the cr, cu, ni, pb and zn in soil samples in urban and rural soil profiles measured with aas. g eo lo gi a c ro at ic a geologia croatica 76/296 ptes belong to anthropogenic factor 1 (heavy industry) (šorša et al., 2017). at a depth of 67 cm in the pr3 profile, the concentration of zn drops sharply, while the concentrations of cr, cu, ni and pb decrease only slightly. at this depth, there are no anthropogenic influences and they originate from the parent material. 3.1.3. bcr sequential extraction procedure of the selected ptes the concentration of cr, ni, pb, and zn in the urban soil profile pr1 is highest in the fraction res, while the concentration of cu is highest in the fraction org (fig. 9; supplements 4.a). this is followed by the fractions res for cu and org, in which in addition to cu, cr and partly zn, ni and pb are bound. profile pr1 is richest in humus and nitrogen (šorša, 2014), so the content of metals bound in the fraction org is significantly higher there than in the other profiles (khadhar et al., 2020). in the femn fraction there is a lot of ni, pb and zn and cu in much lower concentrations, and cr is almost absent in the lower two layers. zinc is almost evenly bound in the femn and org fractions, and the concentrations of pb, ni, cu and cr decrease to zero, respectively, in the upper horizon/layers. nickel in the fraction res is predominantly of geogenic origin and bound to silicates since nickel of anthropogenic origin has a high affinity for binding to feand mn-oxy-hydroxides (mcgrath, 1997). this is probably the reason why its content in the femn fraction is elevated in the lower two layers of profile pr1. nickel concentration in the femn fraction is related to the fe2o3 and mno content in these horizons/layers (supplements 3; šorša, 2014). with increasing fe-mn oxide content, the ni concentration in the femn fraction also increases. lead concentration in pr1 is significantly higher than in the other profiles. lead of anthropogenic origin, especially pb from metallurgical processes, has a higher binding affinity to fe-mn-oxides than to organic material (ettler et al., 2005). consequently, although the profile pr1 contains a high content of humus and nitrogen, more pb is present in the femn than in the fraction org. the lowest concentration of all elements was found in the carb fraction. it is associated with a low content of zn and pb, then with ni and cu in the lower layers, while cr is absent. there is not much regularity in terms of fractions and profile depth. in general, the fraction res decreased and the fraction org of cu and cr as well as the fraction femn of ni, pb and zn increased. the amount of ptes in the fractions in the urban soil profile pr1 is not the result of pedogenic processes in the parent material. the fluctuating concentrations in the fractions are the result of repeated excavations in the area where the profile is located and the repeated mixing of the parent material with anthropogenic artefacts. considering that profile pr1 has been under strong anthropogenic influence for over 2,000 years, it is likely that some of the metals were only weakly bound. in general, the distribution of metal concentration by fraction in the pr1 profile is as follows: res > org > femn > carb, except for cu, which is org > res > femn > carb. in soil profile pr2, the largest fraction of metals is in the fraction res (fig. 9; supplements 4a). the content of humus and nitrogen is highest in the surface horizon, and the concentration of ptes in the fraction org is also highest there. chromium is not present in the femn fraction, while other metals are similarly present in the femn and org fractions. only pb and significantly less zn, cu and ni are bound in the carb fraction. the urban soil profile pr2 is characterised by an enrichment of all the studied ptes in the surface layer. however, the two upper layers and part of the third layer were infilled in 2009 and have no fixed genetic relationship with the rest of the profile. it is likely that some of the material from the immediate vicinity of the profile was used to level the site and some was brought in from elsewhere. however, one can observe an increase in metals bound to the femn fraction with increasing depth and a strong decrease in the deepest layer, which is consistent with the amounts of fe2o3 and mno in the profile (supplements 3; šorša, 2014). the distribution of fractions in profile pr2 is res > femn > org > carb. in soil profile pr3 ptes cr, cu, ni and zn are mainly concentrated in the res fraction and pb in the femn fraction or in figure 9. the diagrams of percentage concentration of cr, cu, ni, pb and zn in the carb, femn, org and res geochemical fractions in soil samples from horizons/ layers in urban and rural soil profiles determined with bcr sep. g eologia c roatica šorša et al.: comparison of urban and rural soils based on speciation of heavy metals by bcr sequential extraction procedure ... 97 deeper horizons in org (fig. 9; supplements 4.a). chromium, cu, ni and zn are almost equally presented in the femn and org fractions. this is a consequence of the concentration of organic matter and fe and mn oxides in the soil. the content of humus and nitrogen is relatively low, except in the two upper horizons. the content of fe2o3 and mno is slightly increased in the whole profile compared to the other urban profiles pr1 and pr2 (supplements 3; šorša, 2014). the lowest amount of ptes is bound in the carb fraction. the exception is pb in the two deepest horizons, where it is almost absent in the res fraction, but evenly distributed in the other three. zinc, pb and cu are enriched in the surface horizon, probably due to the proximity of the ironworks (fig. 7; tab. 4). in the deeper horizons, the metals are predominantly of geogenic origin, with the exception of pb, which is predominantly of anthropogenic origin throughout the profile. the dominant distribution of geochemical fractions in the pr3 profile is res > femn > org > carb, with the exception of pb, which is femn > org > res > carb. the predominant distribution of the studied ptes concentration by fraction in the urban soil profiles is as follows: res > org or femn > carb, except for cu, where org > res > femn > carb. the leaching content of ptes by the fractions shows a large variability due to the different chemical composition of the soil samples. the ranges of variation between the minimum and maximum values are generally large, which is another indicator of the diversity of soil composition by horizon/layer. lead shows large ranges for all fractions, cu for the res and org fractions, ni and zn for res and femn. chromium shows the lowest concentration ranges in all fractions compared to the other ptes, probably because it is predominantly of geogenic origin. based on the geological background and the results of total concentrations of ptes in soil and on bcr sep it can be concluded that ni is also partly of geogenic origin, while cu and zn are mainly of anthropogenic origin. the content and “behaviour” of pb in all fractions differs from that of the other ptes. lead is almost uniformly present in the fractions res, femn and org and varies irregularly in the profiles. lead is predominantly of anthropogenic origin. 3.2. rural soils 3.2.1. mineralogy soil profiles pr4 and pr5 are located on agricultural land and anthropogenic influences are mainly limited to the surface horizons. the minerals identified in the horizons of the rural soil profiles were quartz, phyllosilicates, calcite, dolomite and plagioclase (figs. 6 and supplements 1; supplements 2). quartz is less abundant in pr4, but predominates in profile pr5. this change is followed by the change in phyllosilicate content. the amount of phyllosilicate in pr4 is the highest in the horizons with the lowest quartz content (at a depth of 90 115 cm). the content of phyllosilicates in pr5 increases with depth. calcite and dolomite are present in profile pr4, but not in pr5. plagioclase feldspars are present in both rural profiles. the rural soil profile pr4 is located on carbonate alluvium of the sava river and its mineralogical composition is consistent with the parent material (fig. 2a; supplements 3; pikija, 1987a, b; šorša et al., 2018). hence, it has the highest dolomite content compared to the other profiles. the mineralogy of the second soil profile pr5 indicates that the parent material probably originates from the siliciclastic alluvium of the river kupa (fig. 2a, pikija, 1987a, b; šorša et al., 2018). 3.2.2. total concentration of the selected ptes the surface horizon of profile pr4 is slightly enriched in metals compared to the lower horizons (fig. 7; supplements 4b). subsequently, the content of metals increases strongly in the pseudogley horizon pr4ii /c (58-90 cm) and relict gley horizon pr4 iii /c/g (90-115 cm) (figs. 5 and 7; tab. 4). the concentration of all ptes then gradually decreases in the two deepest horizons. the highest concentrations of all ptes in the entire pr4 profile were measured in the relict gley horizon. the origin of the metals in the profile, especially their high content in this horizon, is questionable. the high content of metals accumulated in the relict gley horizon corresponds to the siliciclastic parent material of the floodplain of the river kupa, although the pr4 profile was excavated in the carbonate floodplain of the river sava (fig. 2a, pikija 1987a, b; šorša, 2014). the reason for this could be the high groundwater table in this area and the frequent floods, which lead to a mixing of water and drained material from both rivers. additionally, the mouth of the river kupa shifted downstream over time and was once located 1 km further north than today (slukan altić, 2004). the concentration and distribution of ptes in the pr4 soil profile was influenced by several factors/processes: the carbonate parent material, then the pedogenic processes with a high groundwater table leading to the development of gley soils, frequent flooding and siliciclastic material brought by the river kupa, and intensive agricultural production. only three horizons (fig. 5) were developed in the drilled soil profile pr5, which is located in the north of the study area, on agricultural land that developed on the siliciclastic alluvium of the river kupa (fig. 2 a,b,c). the concentrations of selected ptes are low. the geochemical maps show a similar distribution of elements in the vicinity of the profile site (šorša & halamić, 2014). the concentration of cu, zn, ni, increases with depth, while pb and cr decrease (fig. 7). the proportion of geogenic elements increases with depth, while elements of partial or complete anthropogenic origin decrease. 3.2.3. bcr sequential extraction procedure of the selected ptes the predominant fraction for cr, cu, ni and zn in the rural soil profile pr4 is res, with the exception of pb, which prevails in the femn or org fractions (fig. 9; supplements 4.b). the second most important fraction is the femn, except for cr and partially cu, which is the most important for pb and the smallest for zn. the concentration of bound metals in org fraction is slightly lower than that of femn. the distribution of the fractions by depth is variable. the concentration of all measured metals increased in the gley horizons in the org and femn fractions and decreased in the res fraction. it is likely that the metals were increasingly dissolved out of the residual minerals. mobilised metals are bound to organic material, clays, and fe-mn oxides due to changes in reduction and oxidation conditions in this horizon. lead and zn are not present (except in the surface horizon), and very few other metals are present in the carb fraction. gene rally, the distribution in profile pr4 is res > femn > org > carb except for pb, which is femn > res > org > carb. in rural soil profile pr5, the dominant fraction of metals is res, with the exception of pb (fig. 9; supplements 4.b). lead is distributed among the fractions res, femn, org and carb depending on the horizons. the concentration of cu, ni and zn in the femn fraction is higher than in the org fraction, which is related to the affinity of each metal and the content of clay, organic matter and femn-oxy-hydroxides (supplements 1 and 3). g eo lo gi a c ro at ic a geologia croatica 76/298 chromium is preferentially bound in the org fraction, cu and ni in the femn fraction, zn equally in both (mcgrath, 1997; ettler et al., 2005; šorša, 2014; khadhar et al., 2020). the concentration of metals in the res fraction increases with depth, except for pb, while it decreases in the fractions femn and org, except for cr and ni. the metal content in the carb fraction is generally very low. the high content of pb and partly of other ptes in the carb fraction in the surface horizon is probably brought in with the dust and adsorbed to soil particles (tessier et al., 1979). the distribution of ptes in profile pr5 is res > femn > org > carb except for pb, which is res > org > femn > carb. the predominant distribution of metal concentration by fraction in the rural geochemical profiles is as follows: res > org or femn > carb, except for pb which is femn > res or org > carb. the large variability of pb and partly also of cu, ni and zn in the fractions in rural soil profiles is due to their anthropogenic or partly anthropogenic origin. rural soil profiles were developed in rural area and therefore the anthropogenic influences were mostly limited to the surface horizons. the parent material and pedogenic development had a dominant influence on the distribution of ptes in the horizons, except for pb. 3.3. risk assessment 3.3.1. risk assessment code the environmental risk of the selected ptes was assessed based on the concentration of ptes in the carb fraction (rath et al., 2009; liu et al., 2010). the risk of ptes in soil profiles varied according to the depth and each pte (tab. 5). the risk assessment by rac in the profiles ranges from no risk to high risk. the rac is highest in urban soil profiles pr1 and pr2, followed by rural profile pr5, and profiles pr3 and pr4 have almost the same rac. in the urban soil profiles, there is no risk for cr and ni in most horizons/layers, and the risk for cu and zn is low. the racs for pb range from no risk in the middle horizons in profile pr3, to low risk (from 1 to 10) in the entire urban soil profile pr1, the upper and two lower layers in pr2, and the upper horizon in pr3. a medium risk (from 11 to 30) exists in the middle layers of profile pr2 and in the two lowest horizons of pr3. there is no risk for pb in most horizons of rural soil profiles pr4 and pr5, but only in the upper horizon of profile pr5 is there a high risk of pb mobilisation (from 31 to 50). there is a low risk for cr, cu and partially for ni. there is a low risk of release of zn from the carb fraction to the environment in the upper horizons of pr4 and pr5. according to the calculated rac, the risk of mobilisation of metals to the environment in urban soil profiles is in the following order: pb > zn > cu > ni > cr, considering the magnitude of the risk. the risk of mobilisation of ptes in rural soil profiles varies as follows: cr > cu > ni > zn > pb. 3.3.2 risk assessment based on the sum of concentrations in the fractions carb, femn and org in the urban area, based on the official land use in the city of sisak (kaminski-kirš, 2002), the urban soil profiles pr1, pr2 table 5. the percentage of the metals cr, cu, ni, pb and zn in the carb fraction in soil profiles and assessment of the risk of release of ptes into the environment (rac). type soil profile carb cr carb cu carb ni carb pb carb zn *em (%) = carbm / (carbm + femnm + orgm + resm) x 100 u rb an so il pr ofi le pr1-a (0-12 cm) 0.20 0.73 0.00 12.92 6.67 pr1-i (12-29 cm) 0.20 0.99 0.00 2.73 6.64 pr1-ii (29-50 cm) 0.20 1.05 0.00 2.44 6.35 pr1-iii (50-70 cm) 0.20 1.01 0.00 2.39 5.77 pr1-iv (70-100 cm) 0.20 2.23 8.54 2.22 7.58 pr1-v (100-120 cm) 0.20 2.21 8.38 2.14 8.02 pr2-i (0-15 cm) 0.11 1.74 0.00 6.40 9.02 pr2-ii (15-33 cm) 0.28 2.65 0.00 212.9 6.30 pr2-iii (33-60 cm) 0.26 2.94 4.14 16.9 2.10 pr2-iv (60-88 cm) 0.13 4.54 5.95 6.61 2.70 pr2-v (88-120 cm) 0.16 1.20 0.00 8.70 0.67 pr3-a (0-14 cm) 0.78 1.24 0.43 1.40 5.52 pr3-i (14-28 cm) 1.15 1.64 0.06 0.11 3.64 pr3-ii (28-67 cm) 1.54 4.55 0.05 0.19 0.00 pr3-cg (67-130 cm) 2.29 5.51 0.06 0.31 0.01 pr3-cg (gr) (130-160 cm) 0.56 3.48 0.08 28.9 0.01 pr3-cg (160-200 cm) 0.92 2.40 3.66 30.0 0.01 ru ra l s oi l p ro fil e pr4-p (0-32 cm) 4.53 3.09 6.25 0.19 5.54 pr4-i/c (32-58 cm) 4.90 4.52 0.06 0.17 0.01 pr4-ii/c (58-90 cm) 3.65 2.83 2.75 0.14 0.00 pr4-iii/c/g (90-115 cm) 4.08 0.00 1.55 0.15 0.00 pr4-iv/c/g (115-160 cm) 7.96 4.34 1.47 0.15 0.01 pr4-v/c/g (160-200 cm) 6.05 4.84 0.05 0.16 0.01 pr5-p (0-30 cm) 3.79 3.16 3.64 344.8 2.53 pr5-g (30-80 cm) 5.58 3.20 3.33 0.27 0.93 pr5-g (80-120 cm) 4.21 3.26 1.47 0.17 0.00 * the percentage of metal m extraction in the carb fraction; m = cr, cu, ni, pb, zn. 1 bold numbers – low risk; 2red coloured numbers – medium risk; 3yellow highlighted numbers – high risk g eologia c roatica šorša et al.: comparison of urban and rural soils based on speciation of heavy metals by bcr sequential extraction procedure ... 99 and pr3 are located in the parks and recreational areas. the prescribed limits for these land use for cr, cu, ni, pb and zn are 500, 300, 200, 500 and 700 mg/kg dry soil, respectively (mesić et al., 2008). in the rural area of sisak, the rural soil profiles pr4 and pr5 correspond to the official land use in areas with soils for agricultural production (kaminski-kirš, 2002). mesić et al. (2008) set limits for cr, cu, ni, pb and zn of 100, 60, 50, 100 and 200 mg/kg dry soil, respectively, for soils for agricultural production. the total concentrations determined with aas (tab. 4) were below the limits for the corresponding land use in all horizons/ layers of both urban and rural soil profiles. consequently, the sum of the concentration of carb, femn and org is lower than the total concentration of the element (tab. 4 and supplements 4.a, b). the risk ratio for all selected ptes in urban and rural soil profiles is rr ≤ 0. there is no risk of contamination in all soil profiles. the estimated risks for the release of ptes to the environment and the risk to the environment and human health are negligible or very low. the soils in the soil profiles are neutral to slightly alkaline, they have a large buffering capacity, a high content of carbonates, humus and nitrogen (šorša, 2014), so the risk of pte mobilisation and the impact on human health are low. 4. conclusion 4.1. urban soils (a) the soil in the urban soil profiles pr1, pr2 and pr3 has mostly no developed horizons, only slightly different soil layers have formed. the pedogenesis of the whole profile pr1 and the upper layers of profiles pr2 and pr3 has been mainly influenced by human activities from ancient times until today, while the influence of the parent material on the soil properties is minor. (b) the mineralogical composition in soil profiles pr1 and pr2 is consistent with the mineralogical composition of the siliciclastic alluvium of the rivers kupa and odra. the mineralogy of profile pr3 corresponds to the mineralogical composition of loess. the urban profile pr1 was under strong anthropogenic influence throughout its depth, while the profiles pr2 and pr3 show anthropogenic influences in their mineralogical composition in their upper part. the lower part of profiles pr2 and pr3 is natural. (c) the concentration of the ptes cr and ni is similar in all soil profiles, but the concentration of cu, pb and zn is higher in the urban soil profiles than in the rural profiles. the distribution of metals along the horizons/layers in the urban profiles pr1 and the upper parts pr2 and pr3 is irregular and strongly influenced by humans’ excavation and contamination. (d) the general distribution of ptes concentration by fraction, determined by bcr sep in urban soil profiles, is as follows: res > org or femn > carb, except for cu where org > res > femn > carb. based on the geological background, pedogenesis, anthropogenic influences and the results of the analyses of bcr sep, it can be concluded that the source of cr is predominantly geogenic and that of ni is partly geogenic and partly anthropogenic. copper and zn are mainly anthropogenic and to a lesser extent geogenic in origin. lead was accumulated in the soil predominantly by anthropogenic input. 4.2. rural soils (a) the soil in rural soil profiles pr4 and pr5 has developed soil horizons. in addition to the parent material, groundwater and surface water had a significant influence on the pedogenic development of the soil in profile pr4. the rural soil profile pr5 shows natural pedogenesis. (b) the mineralogical composition in soil profiles pr4 and pr5 is consistent with the mineralogical composition of the carbonate alluvium of the river sava and the siliciclastic alluvium of the rivers kupa and odra, respectively. the rural soil profiles pr4 and pr5 are located on agricultural land and the anthropogenic influences are mainly limited to the surface horizons/ layers. (c) the concentration of ptes cr and ni is similar in all studied soil profiles, but the concentration of cu, pb and zn is lower in the rural soil profiles than in the urban profiles. pedogenesis in rural soil profile pr4 was shaped by the high groundwater level and the distribution of metals in the horizons was influenced by frequent flooding. profile pr5 shows natural pedogenesis and was influenced by humans only in the surface horizon. (d) distribution by geochemical fraction, determined using bcr sep in rural soil profiles, is res > femn or org > carb, except for pb where femn > res or org > carb. based on the parent material, pedogenic development, limited anthropogenic influences and the results of the analyses of bcr sep, it can be concluded that the parent material and pedogenic development had a predominant influence on the distribution of geochemical fractions in the horizons, except for pb. 4.3. urban vs. rural soil profiles soil horizons were undeveloped or weakly developed in the urban soils, in contrast to the developed horizons in the rural soil profiles. the differences in the mineralogical composition of the urban and rural soil profiles are primarily due to the fact that the parent material in the urban soil profiles was more anthropogenically influenced. the geological background has the greatest influence on the similar concentration of cr and ni in urban and rural soil profiles, but the concentration of cu, pb and zn was significantly higher in urban soil profiles than in rural ones, due to historical land use and repeated excavation and contamination. the distribution by geochemical fraction for cr, ni and zn was similar in all profiles. the distribution of fractions for cu in urban soil profiles and for pb in rural soil profiles was predominantly anthropogenically influenced. 4.4. risk assessment (a) according to the calculated rac of the studied ptes in urban soil profiles, the magnitude of risk is in the following order: pb > zn > cu > ni > cr. the risk of mobilisation of ptes in rural soil profiles varies as follows: cr > cu > ni > zn > pb. the high risk is recorded only in one surface horizon of one rural profile. (b) the results of the total concentration of selected ptes determined by aas were below the limits for the corresponding land use in all horizons/layers of both urban and rural soil profiles. consequently, the sum of the concentration of carb, femn and org is below the prescribed limits. the calculated risk ratio for all studied ptes in urban and rural soil profiles is rr ≤ 0. there is no risk of metal release in any soil profile. acknowledgement this study was supported by the ministry of science, education and sports, republic of croatia scientific project: the basic geochemical map of croatia, (no. 181-1811096-1181). we thank g eo lo gi a c ro at ic a geologia croatica 76/2100 the associated editor zoran peh, reviewer darko tibljaš an anonymous reviewer for their thorough review, which significantly improved the manuscript. references craul, j.p. (1992): urban soil in landscape design.– j. wiley and sons, new york, 416 p. davidson, c.m., thomas, r.p., mcvey, s.e., perala, r., littlejohn, d. & ure, a.m. (1994): evaluation of a sequential extraction procedure for the speciation of heavy metals in sediments.– anal. chim. acta, 291, 277–286. doi: 10.1016/0003-2670(94)80023-5 ettler, v., vaněk, a., mihaljevič, m. & bezdička, p. (2005): contrasting lead speciation in forest and tilled soils heavily polluted by lead metallurgy.– chemosphere, 58, 1449–1459. doi: 10.1016/j.chemosphere.2004.09.084 european commission (2001): report 19775 en of the european commission: the certification of the extractable contents (mass fractions) of cd, cr, cu, ni, pb and zn in freshwater sediment following a sequential extraction procedure bcr701.– competitive and sustainable growth. gleyzes, ch., tellier, s. & astruc, m. (2002): fractionation studies of trace elements in contaminated soils and sediments: a review of sequential extraction procedures.– trends in analytical chemistry, 21, no. 6 + 7, 451–467. doi: 10.1016/ s0165-9936(02)00603-9 greinert, a. (2015): the heterogeneity of urban soils in the light of their properties.– j. soils sediments, 15/8, 1725–1737. doi: 10.1007/s11368-014-1054-6. greinert, a. & kostecki, j. (2019): anthropogenic materials as bedrock of urban technosols.– in: vasenev, v., dovletyarova, e., cheng, z., prokof’eva, t., morel, j. & ananyeva, n. (eds.): urbanization: challenge and opportunity for soil functions and ecosystem services. proceedings of the 9th suitma 2017. springer geography, 11–20. doi: 10.1007/978-3-319-896021_3. kaminski-kirš, n. (2002): generalni urbanistički plan grada siska i dio [general urban plan of the city of sisak – part i – in croatian].– cpa centar za prostorno uređenje i arhitekturu d.o.o. zagreb, 73 p. hooker, p.j. & nathanail, c.p. (2006): risk-based characterisation of lead in urban soils.– chem. geol., 226, 340–351. doi: 10.1016/j.chemgeo.2005.09.028 husnjak, s. (2012): kompilirana pedološka karta grada siska i okolice [compiled pedological map of the city of sisak and its surroundings – in croatian].– unpubl. report, archive of the croatian geological survey, zagreb. husnjak, s. (2014): sistematika tla hrvatske [soil systematics of croatia – in croatian].– hrvatska sveučilišna naklada, zagreb, 375 p. husnjak, s., rubinić, v., halamić, j., šorša, a. & vrbek, b. (2018): characteristics and classification of three urban soils in the sisak city, croatia.– agriculturae conspectus scientificus, 83/3, 231–238. iuss working group wrb (2014): world reference base for soil resources 2014.– world soil resources reports, no. 106, fao, rome. khadhar, s., sdiri, a., chekirben, a., azouzi, r. & charef, a. (2020): integration of sequential extraction, chemical analysis and statistical tools for the availability risk assessment of heavy metals in sludge amended soils.– environ. pollut, 263. doi: 10.1016/j.envpol.2020.114543. lehmann, a. & stahr, k. (2007): nature and significance of anthropogenic urban soils.– j. soils sediments, 7, 247–260. doi: 10.1065/jss2007.06.235 lisac, i. & herić-nekić, s. (1995): contribution to the knowledge of the climate of sisak.– croatian meteorological journal, 30, 79–99. liu, j., chen, y., wang, j., qi, j. wang, c., lippold, h. & lippmann-pipke, j. (2010): factor analysis and sequential extraction unveil geochemical processes relevant for trace metal distributions in fluvial sediments of a pyrite mining area, china.– carbonates and evaporites, 25, 51–63. doi: 10.1007/s13146-010-0007-4 mcgrath, s.p. (1997): chromium and nickel.– in: alloway, b.j. (ed.): heavy metals in soils.– blackie academic and professional, london, 368 p. mesić, h., čidić, a., dominiković alavanja, s., kisić, i., bašić, f., zgorelec, ž., husnjak, s., romić, d., komesarović, b., klaić, d., pernar, n., bakšić, d., vrbek, b., pilaš, i., potočić, n., seletković, i., durn, g., mileusnić, m., nakić, z. & miko, s. (2008): izrada programa trajnog motrenja tala hrvatske s pilot projektom life05 tcy/cro 000105.– in: kučar dragičević, s. (ed.): program trajnog motrenja tala hrvatske [in croatian], croatian environmental agency, zagreb, 131 p. miko, s., durn, g., adamcovà, r., čović, m., dubikovà, m., skalský, r., kapelj, s. & ottner, f. (2003): heavy metal distribution in karst soil from croatia and slovakia.– environmental geology, 45, 262–272. doi: 10.1007/s00254003-0878-y moore d.m. & reynolds r.c. jr. (1997): x-ray diffraction and the identification and analysis of clay minerals.– oxford university press, oxford, 378 p. nieuwenhuize, j., poley-vos, c.h., van der akker, a.h. & van delft, w. (1991): comparison of microwave and conventional extraction techniques for the determination of metals in soils, sediments and sludge samples by atomic spectrometry.– analyst, 116, 347–351. doi: 10.1039/an9911600347 o’riordan, r., davies, j., stevens, c., quinton, j.n. & boyko, ch. (2021): the ecosystem services of urban soils: a review.– geoderma 395, 115076. doi: 10.1016/j.geoderma.2021.115076. pikija, m. (1987a): osnovna geološka karta sfrj 1:100 000, list sisak [basic geological map of the sfrj 1:100,000, sisak sheet – in croatian].– geol. zavod zagreb, savezni geol. zavod, beograd. pikija, m. (1987b): osnovna geološka karta sfrj 1:100 000. tumač za list sisak [basic geological map of the sfrj 1:100,000, explantory notes for sisak sheet – in croatian with english summary].– geol. zavod zagreb, savezni geol. zavod, beograd, 55 p. pouyat, r.v., szlavecz, k., yesilonis, i.d., groffman, p.m. & schwarz, k. (2010): chemical, physical and biological characteristics of urban soils.– in: aitkenhead-peterson, j. & volder, a. (eds.): agronomy monograph 55, urban ecosystem ecology. american society of agronomy, crop science society of america, soil science society of america, madison, usa, 119–155. doi: 10.2134/agronmonogr55.c7 pueyo, m., rauret, g., lück, a.d., yli-halla, b.m., muntau, c.h., quevauvillere, d.ph. & lópez-sánchez, j.f. (2001): certification of the extractable contents of cd, cr, cu, ni, pb and zn in a freshwater sediment following a collaboratively tested and optimised three-step sequential extraction procedure.– j. environ. monit., 243–250. doi: 10.1039/b010235k. rapanat, s., salminen, r., tarvainen, t., krčmovà, k. & cvečkovà (2008): application of a risk assessment method to europe-wide geochemical baseline data.– geochemistry: exploration, environment, analysis, 8, 291–299. doi: 10.1144/1467-7873/08-176 rath, p., panda, u.c., bhatta, d. & sahu, k.c. (2009): use of sequential leaching, mineralogy, morphology, and multivariate statistical technique for quantifying metal pollution in highly polluted aquatic sediments – a case study: brahmani and nandira rivers, india.– journal of hazardous materials, 163, 632–644. doi: 10.1016/j.jhazmat.2008.07.048 reimann, c., filzmoser, p., garret, r.g. & dutter, r. (2008): statistical data analysis explained.– john wiley and sons, ltd. schultz, l.g. (1964): quantitative interpretation of mineralogical composition from x-ray and chemical data for the pierre shale.– u.s. geological survey proffesional paper 391-c, 31 p. slukan altić, m. (2004): povijesni atlas gradova: sisak [historical – towns’ atlas: sisak – in croatian].– sisak state archives & croatian state archives, zagreb, 241 p. sobocká, j. (2003): urban soils vs. anthropogenic soils, their differentiation and classification.– final program and abstracts book, suitma int. conf., july, 9–11. 2003, nancy, france, 41–42. šorša, a. (2014): urban geochemistry of the potentially toxic elements in the soils of the sisak city and its surroundings.– unpubl. phd thesis, faculty of mining, geology and petroleum engineering, university of zagreb, 308 p. šorša, a. & halamić, j. (2014): geochemical atlas of sisak.– public library vlado gotovac sisak, city museum sisak and croatian geological survey, sisak-zagreb, 200 p. šorša, a., durn, g., halamić, j., husnjak, s., garašić, v. & mileusnić, m. (2017): urban geochemistry: sisak in croatia, a long-lasting historical, urban and industrial city.– geochemistry: exploration, environment, analysis, 17/2, 159–163. doi: 10.1144/geochem2015-395. šorša, a., peh, z. & halamić, j. (2018): geochemical mapping the urban and industrial legacy of sisak, croatia, using discriminant function analysis of topsoil chemical data.– journal of geochemical exploration, 187, 155–167. doi: 10.1016/j. gexplo.2017.07.014. starkey h.c., blackmon p.d. & hauff p.l. (1984): the routine mineralogical analysis of clay-bearing samples. – u.s. geological survey bulletin 1563, 31 p. tessier, a., campbell, p.g.c. & bisson, m. (1979): sequential extraction procedure for the speciation of particulate trace metals.– analytical chemistry, 51/7, 844–851. doi: 10.1021/ac50043a017 ure, a.m., quevauviller, p.h., muntau, h. & griepnik, b. (1993): speciation of heavy metals in soils and sediments. an account of the improvement and harmonization of extraction techniques undertaken under the auspices of the bcr of the commission of the european communities.– international journal of environmental analytical chemistry, 51, 135–151. doi: 10.1080/03067319308027619 zimmerman, a.j. & weindorf, d.c. (2010): heavy metal and trace metal analysis in soil by sequential extraction: a review of procedures.– hindawi publishing corporation, international journal of analytical chemistry, 387803. doi: 10.1155/2010/387803 g eologia c roatica šorša et al.: comparison of urban and rural soils based on speciation of heavy metals by bcr sequential extraction procedure ... 101 supplement 1. mineral composition of soil from urban and rural soil profiles pr1, pr2, pr3, pr4 and pr5 determined by x-ray diffraction. type of soil profiles soil samples from soil horizons/layers qtz phil cal dol pi cri wt. % u rb an so il pr ofi le s pr1-a (0-12 cm) 46 32 11 7 4 pr1-i (12-29 cm) 48 30 9 9 4 pr1-ll (29-50 cm) 56 26 11 4 3 pr1-iii (50-70 cm) 49 31 11 4 4 pr1-iv (70-100 cm) 57 27 10 3 3 pr1-v (100-120 cm) 58 29 8 3 2 pr2-i (0-15 cm) 47 27 9 14 3 pr2-ii (15-33 cm) 45 17 20 14 4 pr2-iii (33-60 cm) 38 31 8 20 3 pr2-iv (60-88 cm) 40 42 4 10 4 pr2-v (88-120 cm) 37 47 3 10 3 pr3-a (0-14 cm) 59 32 5 4 pr3-i (14-28 cm) 55 37 4 4 pr3-ii (28-67 cm) 53 35 7 5 pr3-cg (67-130 cm) 52 39 5 4 pr3-cg (gr) (130-160 cm) 47 44 6 3 pr3-cg (160-200 cm) 52 40 5 3 ru ra l s oi l p ro fil es pr4-p (0-32 cm) 42 27 4 23 4 pr4-i/c (32-58 cm) 35 27 9 26 3 pr4-ii/c (58-90 cm) 33 42 6 17 2 pr4-iii/c/g (90-115 cm) 33 45 19 4 pr4-iv/c/g (115-160 cm) 36 28 11 21 4 pr4-v/c/g (160-200 cm) 39 27 9 23 2 pr5-p (0-30 cm) 71 26 3 pr5-g (30-70 cm) 64 32 4 pr5-g (70-130 cm) 60 36 4 abbreviations: qtz, quartz; phil, phyllosilicates; cal, calcite; dol, dolomite, pl, plagioclase and cri, cristobalite. supplement 2. x-ray diffraction patterns of selected representative soil samples: pr1-ii (29-30 cm), pr2-iii (33-60 cm), pr3-ii (28-67 cm), pr4-p (0-32 cm) and pr5g (30-80 cm). abbreviations for minerals are the same as in supplement 1. g eo lo gi a c ro at ic a geologia croatica 76/2102 supplements 3. the concentration (in wt. %) of major elements oxides and ba in soil samples from soil profiles pr1, pr2, pr3, pr4 and pr5. sio2 al2o3 fe2o3 cao mgo na2o k2o mno tio2 p2o5 cr2o3 ba *loi sum soil profile / detection limit 0.1 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.001 0.01 0.1 0.01 u rb an so il pr ofi le s pr1-a (0-12 cm) 58.2 8.89 3.64 6.17 1.95 0.79 1.45 0.09 0.62 0.70 0.012 0.03 16.5 99.0 pr1-i (12-29 cm) 58.4 8.35 3.52 7.28 1.95 0.75 1.39 0.10 0.57 0.81 0.017 0.03 15.8 99.0 pr1-ii (29-50 cm) 60.4 7.92 3.36 7.04 1.46 0.72 1.31 0.10 0.48 1.04 0.012 0.03 15.6 99.5 pr1-iii (50-70 cm) 62.0 7.87 3.28 6.81 1.30 0.74 1.32 0.10 0.52 1.07 0.011 0.03 14.5 99.5 pr1-iv (70-100 cm) 61.5 7.92 3.21 6.34 1.17 0.70 1.33 0.09 0.59 1.07 0.010 0.02 14.9 98.3 pr1-v (100-120 cm) 62.0 7.75 3.25 6.81 1.27 0.71 1.34 0.10 0.48 1.07 0.013 0.03 14.8 98.9 pr2-i (0-15 cm) 49.8 9.47 3.84 10.1 3.60 0.89 1.49 0.10 0.60 0.24 0.013 0.03 19.7 99.5 pr2-ii (15-33 cm) 51.8 7.05 2.80 13.5 3.82 0.96 1.17 0.07 0.45 0.12 0.007 0.02 17.6 99.3 pr2-iii (33-60 cm) 47.2 9.99 3.72 11.3 5.34 0.83 1.59 0.08 0.66 0.11 0.015 0.03 18.5 99.4 pr2-iv (60-88 cm) 54.6 14.7 5.45 3.80 2.54 0.87 2.19 0.11 0.95 0.19 0.018 0.04 13.0 98.4 pr2-v (88-120 cm) 53.8 14.8 5.66 4.08 2.90 0.83 2.23 0.12 0.86 0.19 0.019 0.04 13.7 99.3 pr3-a (0-14 cm) 62.8 13.7 5.39 1.14 1.43 1.23 2.08 0.13 1.08 0.16 0.014 0.05 9.92 99.1 pr3-i (14-28 cm) 63.7 14.6 5.76 0.97 1.44 1.29 2.19 0.11 1.13 0.15 0.012 0.06 7.88 99.3 pr3-ii (28-67 cm) 64.2 15.1 5.73 0.72 1.56 1.33 2.34 0.10 1.18 0.15 0.015 0.05 6.90 99.3 pr3-cg (67-130 cm) 63.4 15.8 5.70 0.63 1.56 1.38 2.39 0.08 1.16 0.11 0.024 0.05 6.92 99.2 pr3-cg (gr) (130-160 cm) 62.5 17.6 4.44 0.50 1.10 0.94 2.18 0.03 1.20 0.03 0.018 0.05 8.55 99.1 pr3-cg (160-200 cm) 60.3 17.4 5.78 0.56 1.29 0.98 2.29 0.03 1.07 0.05 0.025 0.05 9.16 98.9 ru ra l s oi l p ro fil es pr4-p (0-32 cm) 48.5 9.37 3.49 10.2 5.34 0.83 1.65 0.08 0.62 0.20 0.010 0.03 18.9 99.2 pr4-i/c (32-58 cm) 44.5 10.6 3.93 11.9 5.57 0.82 1.74 0.09 0.65 0.11 0.014 0.03 19.4 99.4 pr4-ii/c (58-90 cm) 45.8 14.8 5.44 7.29 4.70 0.74 2.35 0.05 0.75 0.14 0.017 0.04 17.4 99.5 pr4-iii/c/g (90-115 cm) 52.6 17.5 7.12 1.78 2.12 0.78 2.51 0.15 0.89 0.16 0.021 0.05 13.5 99.2 pr4-iv/c/g (115-160 cm) 42.5 11.2 4.32 12.4 5.56 0.77 1.77 0.12 0.69 0.11 0.013 0.03 20.1 99.5 pr4-v/c/g (160-200 cm) 44.5 9.32 3.48 13.0 6.10 0.80 1.52 0.08 0.63 0.10 0.013 0.03 19.9 99.5 pr5-p (0-30 cm) 67.6 13.1 4.69 0.52 1.07 1.03 2.21 0.12 0.97 0.16 0.016 0.04 7.72 99.2 pr5-g (30-70 cm) 66.6 13.9 5.15 0.52 1.17 1.01 2.34 0.11 0.95 0.12 0.015 0.04 7.20 99.1 pr5-g (70-130 cm) 64.5 15.0 5.97 0.46 1.29 0.97 2.52 0.09 0.90 0.11 0.015 0.04 7.08 98.9 * loi – loss on ignition g eologia c roatica šorša et al.: comparison of urban and rural soils based on speciation of heavy metals by bcr sequential extraction procedure ... 103 supplements 4a. the concentration in (mg/kg) of cr, cu, ni, pb and zn as ptes in geochemical fractions, obtained with bcr sep, of soil samples from urban soil profiles pr1, pr2 and pr3. soil profile pr1 chromium (mg/kg) cupper (mg/kg) nickel (mg/kg) lead (mg/kg) zinc (mg/kg) carb femn org res carb femn org res carb femn org res carb femn org res carb femn org res pr1-a (0-12cm) *< dl < dl 4.08 14.2 0.71 1.70 51.5 44.0 0.00 2.75 7.80 30.0 4.20 17.4 28.1 94.2 9.44 25.5 29.2 77.4 pr1-i (12-29cm) < dl < dl 3.70 14.4 1.24 2.93 71.5 49.3 0.00 3.95 7.16 29.4 4.82 17.8 18.0 136 9.79 27.1 28.7 81.7 pr1-ii (29-50cm) < dl < dl 3.79 13.8 1.53 3.54 87.7 53.6 0.00 3.91 8.41 28.4 4.79 13.6 21.6 156 10.1 31.4 35.8 82.0 pr1-iii (50-70cm) < dl < dl 3.74 14.2 1.44 4.50 82.0 54.2 0.00 3.30 7.43 26.8 5.00 26.7 23.8 154 8.55 33.4 28.1 78.0 pr1-iv (70-100cm) < dl < dl 6.20 11.3 3.28 12.4 77.2 54.6 3.58 16.7 9.00 12.7 5.02 81.5 68.1 71.4 11.4 58.4 21.0 59.0 pr1-v (100-120cm) < dl < dl 5.64 11.9 3.46 12.9 80.8 59.6 3.56 16.2 8.82 13.9 5.03 68.9 71.5 89.1 12.6 59.3 24.1 61.1 soil profile pr2 chromium (mg/kg) cupper (mg/kg) nickel (mg/kg) lead (mg/kg) zinc (mg/kg) carb femn org res carb femn org res carb femn org res carb femn org res carb femn org res pr2-i (0-15cm) < dl < dl 14.4 18.1 0.91 1.22 20.5 29.6 0.00 4.10 8.19 33.9 5.65 10.7 24.2 47.7 17.8 34.6 45.5 98.9 pr2-ii (15-33cm) < dl < dl < dl 12.6 0.95 1.27 10.3 23.4 0.00 1.92 4.72 26.1 6.12 6.55 10.8 24.1 4.96 7.7 14.8 51.4 pr2-iii (33-60cm) < dl < dl < dl 13.6 0.96 3.71 6.4 21.6 1.85 13.3 6.12 23.4 5.90 5.83 9.08 14.1 1.48 10.3 7.1 51.6 pr2-iv (60-88cm) < dl < dl 6.98 20.2 2.07 7.31 5.29 30.9 3.70 22.0 10.3 26.2 4.27 30.6 11.0 18.7 2.84 20.4 13.0 68.7 pr2-v (88-120cm) < dl < dl < dl 22.0 0.56 2.63 5.43 37.9 0.00 10.3 6.37 42.4 4.06 6.78 8.99 26.9 0.67 5.8 7.3 86.7 soil profile pr3 chromium (mg/kg) cupper (mg/kg) nickel (mg/kg) lead (mg/kg) zinc (mg/kg) carb femn org res carb femn org res carb femn org res carb femn org res carb femn org res pr3-a (0-14cm) 0.20 0.57 5.19 19.5 0.32 4.18 3.71 17.5 0.10 2.94 2.86 17.4 0.60 21.6 8.50 12.1 7.65 23.8 23.8 83.5 pr3-i (14-28cm) 0.30 0.80 4.61 20.4 0.35 3.65 1.71 15.7 < dl 3.16 2.38 17.8 < dl 16.5 6.00 9.60 3.25 10.3 11.7 64.0 pr3-ii (28-67cm) 0.45 1.63 3.76 23.4 1.01 3.19 1.19 16.8 < dl 3.38 2.57 21.2 < dl 8.87 4.25 5.88 < dl 3.05 3.85 57.1 pr3-cg (67-130cm) 0.69 2.08 4.62 22.8 1.16 2.96 1.59 15.4 < dl 2.31 2.55 17.8 < dl 5.50 2.79 3.57 < dl 3.69 4.42 46.8 pr3-cg (gr) (130-160cm) 0.15 1.94 5.46 19.1 0.70 3.19 1.81 14.4 < dl 1.51 3.31 11.3 3.53 3.27 4.41 1.00 < dl 3.07 4.12 25.1 pr3-cg (160-200cm) 0.30 2.49 6.01 23.7 0.58 3.45 2.01 18.1 0.90 3.07 4.67 15.9 3.53 3.14 4.51 0.60 < dl 3.75 6.31 30.6 * detection limit (dl) in mg/kg of cr<0.072; cu<0.010; ni<0.027; pb<0.073; zn<0.006. supplements 4b. the concentration in (mg/kg) of cr, cu, ni, pb and zn as ptes in geochemical fractions, obtained with bcr sep, of soil samples from rural soil profiles pr4 and pr5. soil profile pr4 chromium (mg/kg) cupper (mg/kg) nickel (mg/kg) lead (mg/kg) zinc (mg/kg) carb femn org res carb femn org res carb femn org res carb femn org res carb femn org res pr4-p (0-32cm) 0.95 2.06 3.59 14.4 0.70 1.34 7.49 13.1 1.63 5.30 2.76 16.4 < dl 12.3 7.30 < dl 4.56 12.1 9.86 55.9 pr4-i/c (32-58cm) 1.03 2.06 3.67 14.2 0.95 2.49 3.48 14.1 *< dl 5.12 1.94 16.8 < dl 8.02 3.45 9.40 < dl 2.01 2.22 46.6 pr4-ii/c (58-90cm) 0.97 1.87 5.49 18.2 0.75 2.09 4.04 19.7 0.85 2.98 2.93 24.2 < dl 9.10 6.25 11.2 < dl 2.16 3.07 64.9 pr4-iii/c/g (90-115cm) 1.39 2.24 8.03 22.5 0.00 4.97 2.16 20.5 0.58 8.16 5.92 22.8 < dl 11.3 3.17 9.62 < dl 10.0 9.27 65.0 pr4-iv/c/g (115-160cm) 1.82 1.11 4.16 15.8 0.93 1.34 2.74 16.4 0.45 9.71 1.84 18.7 < dl 7.46 9.24 7.71 < dl 1.44 1.74 51.9 pr4-v/c/g (160-200cm) 1.14 0.90 4.24 12.6 0.88 1.94 2.61 12.7 < dl 8.89 2.03 17.0 < dl 7.16 9.75 5.50 < dl 1.54 1.71 39.2 soil profile pr5 chromium (mg/kg) cupper (mg/kg) nickel (mg/kg) lead (mg/kg) zinc (mg/kg) carb femn org res carb femn org res carb femn org res carb femn org res carb femn org res pr5-p (0-30cm) 0.86 0.93 5.70 15.2 0.66 4.63 2.06 13.6 1.05 7.41 2.13 18.3 11.4 < dl 6.86 7.12 1.59 6.28 5.81 49.3 pr5-g (30-80cm) 1.25 1.06 4.43 15.7 0.68 4.42 1.50 14.7 0.81 2.33 2.61 18.6 < dl < dl 7.07 6.60 0.57 4.92 3.91 51.9 pr5-g (80-120cm) 0.90 1.45 3.71 15.3 0.91 4.01 1.35 21.6 0.45 2.46 3.91 23.8 < 0.073 12.7 2.34 6.30 < 0.006 3.73 3.26 58.6 * detection limit (dl) in mg/kg of cr<0.072; cu<0.010; ni<0.027; pb<0.073; zn<0.006. 2024 | 77/1 | 15–28 | 5 figs. | 7 tabs. | 1 pl. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction microvertebrate assemblages are important indicators of palaeoenvironment, the biochronological position of the faunas and their palaeogeographic relationships. the pannonian basin in central europe experienced profound palaeogeographic changes during the neogene. the formation of the basin took place mostly in the early and middle miocene, as a result of large-scale migration and deformation of lithospheric microplates (horváth et al., 2006). numerous small vertebrate localities are known in the pannonian basin from this time interval, providing useful information on the evolutionary and palaeoenvironmental changes in the area (hír et al., 2016, 2017, 2019). however, these are mostly located in the northern and eastern parts of the basin. only sporadic finds have been reported in the south (paragovo, veliko selo and leštane in serbia (marković & milivojević, 2010), several locations in the mecsek mts. in hungary (kordos & solt, 1984, kordos, 1985), or on the eastern border of the basin (e.g., subpiatră, vârciorog, tăşad in w romania) (hír et al., 2016, 2017). here we present a new vertebrate assemblage collected in the se part of the mecsek mts., sw hungary, and discuss its palaeoenvironmental and palaeogeographic significance. 2. geological setting the sampled outcrop lies along the se margin of the mecsek mts., in a relatively deep gully system south of the village of hi middle miocene (late badenian) microvertebrates from hidas, sw hungary jános hír1,*, márton venczel2,3 and krisztina sebe4 1 municipal museum of pásztó, hungary; (*corresponding author: hirjanos@gmail.com) 2 �babeș-bolyai�university,�cluj-napoca,�romania 3 �țării�crișurilor�museum,�oradea,�romania;�(mvenczel@gmail.com) 4 �hun-ren–mtm–elte�research�group�for�palaeontology;�(sebekrisztina.geo@gmail.com) doi: 10.4154/gc.2024.03 abstract up�to�the�present,�no�terrestrial�vertebrate�fauna�has�been�published�from�the�pre-pannonian�miocene of sw hungary. in 2022 a microvertebrate assemblage was unearthed from a lime mud bed of�the�middle�miocene�hidas�formation,�in�an�abandoned�coal�mining�field�close�to�hidas�in�the� mecsek�mts.�the�herpetofauna�and�the�rodent�material�are�described�here.�fossil�findings�point� to�the�late�badenian�mn�7+8�zone,�which,�together�with�the�earlier�results�based�on�the�marine� mollusc fauna, narrows the age of the unit to ~13.5–13.3 ma. the amphibians and reptiles are aquatic, semiaquatic or periaquatic forms. sedimentary features and the accompanying freshwater gastropod fauna are indicative of a shallow pond or a paludal depositional environment. crocodylian�finds�reported�earlier�from�the�hidas�formation�indicate�a�subtropical�climate,�just�before� the�end�of�the�miocene�warm�period�in�central�europe.�among�the�rodents,�glirids�and�flying�squirrels as well as democricetodon and megacricetodon indicate the presence of humid arboreal vegetation�around�the�site.�the�rodent�taxa�are�well�known�from�the�middle�miocene�faunas�of�northern�hungary,�western�romania�and�from�the�upper�freshwater�molasse�of�southern�germany� and switzerland. the rodent material does not show characteristics of an insular fauna, e.g. gigantism or endemism. consequently, although the coeval palaeogeography of the region has been described�as�an�archipelago�in�the�central�paratethys,�with�the�mecsek�mts.�being�one�of�the�islands, the area must have had ecological connections towards the northern and eastern parts of the pannonian basin, and the marine areas within the archipelago did not form a barrier against the�distribution�of�microvertebrates.�the�corridor�could�have�been�located�towards�the�ne�from�the� mecsek�mts.,�across�the�elevated�basement�blocks�of�central�hungary. das (fig. 1.), at the coordinates 46.248723° n, 18.503948° e. due to the steep topography, it is dissected by dislocation planes of landslides, but displacement along them is minor and it is possible to assemble the probable sedimentary succession, composed of three conformable layers: 1) mollusc coquina, composed dominantly of brackish-water taxa: the gastropods terebralia and nassa, and small sized ostreids. the shells are mostly oriented parallel to the bedding plane. 2) whitish grey lime mud, at least 0.8–1 m thick. variably porous, crumbling, without visible internal sedimentary structures. in the field it was possible to discern planorbis shells and bone fragments. it must have been deposited in a shallow freshwater environment, like a pool or a swamp. 3) dark brown lignite, at least 1 m thick. it contains lenses of light grey clay and a few cm thick beds of yellowish white, porous dacite tuff, with mm sized biotite crystals. the succession can be classified into the coal-bearing hidas formation (fig. 2). both the planorbis-bearing layers and the coquina with ostreids are typical for the interbeds between the coal layers (csepreghyné meznerics, 1950, bohnné havas, 1973). the age of the unit is upper badenian in the regional, central paratethys stratigraphy (lower serravallian in standard global stratigraphy) (selmeczi et al., 2023). the formation is composed of alternating lignite, clay, marl, mollusc coarticle history: manuscript recieved: september 29, 2023 revised�manuscript�accepted:�january�16,�2024 available�online:�february�27,�2024 keywords:�herpetofauna,�rodent�fauna,�pannonian� basin,�mecsek�mountains,�palaeogeography mailto:sebekrisztina.geo@gmail.com g eo lo gi a c ro at ic a geologia croatica 77/116 quina and lime mud layers and accumulated in brackish and freshwater environments. only sporadic vertebrate remains have been known from the hidas formation so far. from the coal mine in the village of hidas, kordos (1985) reported steneofiber sp., diplocynodon sp. and „crocodile” bones, citing vadász (1935). kordos (1985) also mentions a rhinocerotidae tooth from the hidas formation, from the shaft of the (jurassic) coal mine near the village of máza, found at the boundary between the mesozoic and the overlying miocene beds. the hidas formation does not occur in that area where the basement is overlain by the lower miocene, fluvial szászvár formation, therefore we consider this mention to have an erroneous lithostratigraphic classification. an otolith assemblage consisting of gobius sp., citharus sp. and soleidae was reported from the brackish-water layers of the hidas formation, (baranyai, 2010). 3. material and methods two tons of sediment were collected from the fossiliferous level at the studied outcrop. they were air-dryed on textile in the sunshine and subsequently soaked in water and some h2o2. the samples were screen-washed using a sieve system with a 0.5 mm mesh size. sorting was carried out by the co-workers of the municipal museum of pásztó and by the authors. the fossil material belongs to the collections of the municipal museum of pásztó (mmp. 2022.1.–2022.74. and mmp. 2023.5–2023.28.). the measurements were taken using an mbs-10 stereomicroscope. the dimensions are given in mm. the digital images were taken using a canon eos 400 d digital camera equipped with canon mp-e65 mm and canon ef 60 mm macro-objectives. the retouches on micromammal teeth were made by jh. the systematics of the rodents follows mckena & bell (1997). the anatomical nomenclature of amphibians and squamate reptiles follows venczel & hír (2013), while in rodents the nomenclature of the dental morphology is after cuenca-bescos (1988), daxner-höck (2010), daxner-höck & höck (2015) for sciurids, mein & freudenthal (1971) for cricetids and daams (1981, 1985) for glirids. abbreviations in the text: l: maximal antero-posterior length of the occlusal surface of a tooth; w: maximal labio-lingual width of the occlusal surface of a tooth; p4: upper premolar; p4: lower premolar; m1-m2m3: upper molars; m1-m2-m3: lower molars; fr.: fragment figure 1. location and appearance of the studied outcrop. abbreviations: t – tuff; c – clay lense. figure 2. stratigraphic position of the fauna (indicated by star). lithostratigraphy of the mecsek mountains after sebe et al. (2019); chronostratigraphy after kováč et al. (2018). g eologia c roatica hir et al.: middle miocene (late badenian) microvertebrates from hidas, sw hungary 17 4. systematic description class: amphibia linnaeus, 1758 order urodela duméril, 1806 family salamandridae goldfuss, 1820 genus lissotriton bell, 1839 lissotriton rohrsi (herre, 1955) figs. 3a-c referred material: one atlas (mmp.2023.5.1), one trunk vertebra (mmp.2023.6.1), one humerus (mmp.2023.7.1). description. atlas. the specimen is well-preserved and might have belonged to a relatively large adult individual. the anterior cotyles are circular and face anterodorsally (i.e., obliquely), whereas the tuberculum interglenoideum is wide and flattened. the neural arch is moderately vaulted and provided with a low and short neural ridge, flanked by two lateral crests delimiting a posteriorly tapering triangle surface (fig. 3a). trunk vertebra. the centrum is opisthocoelous and moderately elongated. the neural arch is vaulted and provided with a high and posteriorly widening neural spine. pits of various sizes occur on the dorsal margin of the neural spine; however, it is devoid of any pustular sculpture (fig. 3b). humerus. mmp.2023.7.1 represents a proximal fragment. the caput humeri is rounded and well ossified representing an adult individual. the processus dorsalis humeri projects at an angle of about 45° from the main humeral shaft. the crista ventralis humeri is moderately developed. comments. the referred remains might have belonged to two different sized individuals, the atlas probably representing a larger individual, compared to the trunk vertebra that correfigure 3. urodeles and anurans from the middle miocene of hidas, hungary. a-c: lissotriton rohrsi, atlas (a), trunk vertebra (b), humerus (c); d-k: latonia seyfriedi, d, e – frontoparietal; e – g, maxillae; h, i – angulars; j, k – atlas. a, b, d, h, i – dorsal views, j – lateral view, e, k – ventral views, e, f – labial views, g – lingual view, j – anterior view. scale bar = 2 mm. g eo lo gi a c ro at ic a geologia croatica 77/118 sponds to a comparatively smaller individual. in fact, the description of lissotriton (= triturus) rohrsi (herre, 1955) from the middle miocene (mn 6) type locality of dĕvínská nová ves (neudorf, dévényújfalu), slovakia (estes, 1981), corresponds exactly to those of the referred specimens. assignment of the proximal humerus is based on overall morphological similarity with those of lissotriton members. unfortunately, apart from the vertebrae, no other skeletal parts in europe have been referred to this species, considered as part of the l. vulgaris group (ivanov, 2008; venczel & hír, 2013; georgalis et al., 2019). an atlantal specimen (mmp.2009.668), referred as lissotriton cf. rohrsi, from the sarmatian (mn 7+8) locality of felsőtárkány 3/10, n hungary appears with a less elongated centrum and the tuberculum interglenoideum is slightly divided (venczel & hír, 2013, fig. 25). trunk vertebrae, also with a slightly different morphology (i.e., neural spines not widened at their anterior section, but bifurcating in their posterior part) have been identified as lissotriton aff. rohrsi from the early miocene (mn 4) locality of mokrá western quarry, czech republik (ivanov, 2008), or as lissotriton sp. (l. vulgaris group), possessing higher neural spines, from the latest miocene (mn 13/14) of maramena, greece (georgalis et al., 2019). further reports of the above taxon are from the early miocene (mn 4) of oberdorf (sanchíz 1998a) and late miocene (mn 9) of götzendorf (miklas, 2002), both from austria. the material also contains several strongly fragmentary specimens that cannot be identified below the familial level (i.e., salamandridae indet.). family alytidae fitzinger, 1843 genus latonia meyer, 1843 latonia seyfriedi meyer, 1843 figs. 3d-k, 4a-c. referred material: two frontoparietals (mmp.2023.8.1-2.), 25 fragmentary maxillae (mmp.2023.9.1-25), eight angulars (mmp.2023.10.1-8), five atlases (mmp.2023.11.1-5), 15 presacral ver tebrae (mmp.2023.12.1-15), one sacral vertebra (mmp.2023.13.1.), one ilium (mmp.2023.14.1.). description. frontoparietal. both available specimens are azygous and covered dorsally by a strong secondary sculpture. in mmp.8.1. the intertubercular space is infilled by the fine grained light grey matrix (fig. 3d), whereas the ventral surface displays a medial sagittal fissure line that may correspond to the fusion line of the parietal parts (fig. 3e). the ventral posteromedial part is developed into a deep concavity that corresponds to the frontoparietal incrassation (roček, 1994). maxilla. most specimens are very damaged. the labial surface, especially on its dorsoposterior part, is covered by a secondary sculpture observed even in the small-sized specimens. the secondary sculpture consists of a framework of irregularly perforated bone (roček, 1994), which is typical for l. seyfriedi (fig. 3e, f). the lingual surface displays a wide and moderately prominent lamina horizontalis delimiting ventrally the pars dentalis; posteriorly the lamina horizontalis projects into a prominent pterygoid process, whereas its base is connected to a crest delimiting a shallow posterior depression (fig. 3g). angular. it is a slightly s-shaped bone with the anterior part curved medially and compressed mediolaterally, whereas its posterior part is more robustly built and widened into a spoon-like pars spatulata (not preserved in any of the available specimens). mmp.2023.10.1. is the largest specimen, rebuilt (i.e., glued together) from two broken parts. the posterodorsal part is broken off at the level of the coronoid process (fig. 3h); the meckel’s groove is relatively deep, extending sinuously on the dorsal and more anteriorly on the dorsolateral part of the bone. in mmp.2023.10.2. the posterior coronoid process is also preserved, positioned nearly at a right angle to the anterior coronoid process (fig. 3i). atlas. in all the available specimens only the atlantal centra are preserved (fig. 3j, k). the anterior cotyles are distinctly separated, their articular surface is roughly rectangular, standing obliquely to the horizontal surface at about 45°. the anterior part of the ventral lamina is protruding anteriorly below the deeply concave articular space. the ventral surface of the centrum bears a prominent ventral crest, whereas the posterior cotyle is circular. presacral vertebrae. in all specimens only the vertebral centra are preserved (fig. 4). the centrum is opisthocoelous with a more or less hemicylindrical ventral surface, and with strong dorsoventral flattening (fig. 4a). sacral vertebra. the single specimen preserves only the centrum. it is provided with an anterior and two posterior condyles. the posterior margins of the posterior condyles are damaged (fig. 4b). ilium. the mmp.2023.14.1. specimen preserves the acetabular region of a relatively large individual. the acetabular surface exhibits a sinuous anterior margin extending into a narrowed dorsal surface, whereas anteroventrally it projects beyond the margin of the reduced preacetabular region (fig. 4c). the supraacetabular region is extensive, but its dorsoposterior part is broken off. the dorsal tubercle is oval and thickened, whereas posterior to it there is a deep supraacetabular fossa. comments. diagnostic features of this large sized alytid frog are among others the widened frontoparietal table bearing an extensive secondary sculpture on the frontoparietal and that the frontoparietal table is more reduced in discoglossus and latonia nigriventer (see in biton et al., 2013). the labial surface of the maxillae also bears a secondary sculpture, this attribute lacking in latonia vertaizoni (roček, 1994), in l. ragei (hossini, 1993), latonia sp. from maramena (georgalis et al. 2019), and in recent l. nigriventer and members of discoglossus (biton et al., 2013). family palaeobatrachidae cope, 1865 genus palaeobatrachus sp. figs. 4d-k referred material: two frontoparietals (mmp.2023.15.1-2.), three maxillae (mmp.2023.16.1-3.), one sphenethmoid (mmp.2023.17.1.), 12 angulars (mmp.2023.18.1-12), one humerus (mmp.2023.19.1.). description. frontoparietal. the specimen mmp.2023.15.1. preserves the anterior half of an azygous frontoparietal. the dorsal surface displays two well-defined parasagittal crests being parallel in the posterior part of the preserved fragment; however, these diverge at the level of the pineal foramen, reaching the lateral margins of the bone (fig. 4d). in ventral view, the contact area with the sphenethmoid is marked by a striated area on the anterolateral sides of the bone (fig. 4e). the second specimen lacks the parasagittal crests and its lateral sides are strongly eroded. maxilla. in the available specimens the anteriormost parts contacting the premaxilla and the posterior (i.e., toothless) parts are not preserved (fig. 4f, g). the maxillary nasal process is moderately high and somewhat damaged. the tooth crowns are g eologia c roatica hir et al.: middle miocene (late badenian) microvertebrates from hidas, sw hungary 19 broken off, but the tooth sockets preserve on each side osseous tuberosities, which are typical for palaeobatrachids (sanchíz 1998b). sphenethmoid. the only specimen preserved the anterior part of a relatively small individual, indicated by the fact that the rostrum is not completely ossified (fig. 4h). in anterior view, an obliquely placed bony lamella divides the olfactory canal, situated medially, and the orbitonasal foramen, which conveyed the ophthalmic nerve (canalis ramus medialis nervi ophtalmici), situated dorsolaterally. the former structure is about twice as large as the latter. the dorsal surface of the bone displays an anteriorly tapering crest, which in the living animal marks the contact area of the overlying frontal, situated posteriorly, and the nasal bones, situated anteriorly. angular. the available specimens are fragmentary, most of them preserving the more robustly built area bearing the coronoid process. however, the specimen mmp.2023.18.1. preserves part of the moderately widened posterior portion (i.e., pars spatulaeformis praearticularis) (fig. 4i). the meckel’s groove is wide, sinuous and delimited by sharp bony lamellae; the coronoid process appears as a low tuberosity, situated on the lingual side of the angular (fig. 4i, j). humerus. the only available small-sized specimen preserves the distal part of a humerus (fig. 4k). from the humeral ball, apparently positioned medially, only its base is preserved. the ventral cubital fossa is lacking, a typical feature for palaeobatrachids (see e.g., venczel, 2004: fig. 5: e, f). comments. based on the available specimens, differentiation of the two late badenian palaeobatrachid species known from the pannonian basin (i.e., palaeobatrachus hiri and p. codreavladi) is not possible (roček et al., 2021). family: pelobatidae bonaparte, 1850 genus pelobates wagler, 1830 pelobates sp. figs. 4l, m. referred material: one maxillary fragment (mmp.2023. 20.1.), one right ilium (mmp.2023.21.1.). description. maxilla. the labial surface is shallowly convex and bears a primary sculpture on its dorsal part (fig. 4l). unfortunately, the sculpture is mostly eroded preserving only the base of that structure. the lower part of the labial surface is smooth, extending parallel to the ventral (i.e., tooth bearing) margin. ilium. the only specimen preserves the labial region and the posterior part of the iliac shaft (fig. 4m). the iliac shaft is reduced to a dorsal ridge and the dorsal protuberance is lacking. a little wasting is present between the acetabular region and the iliac shaft, due to the presence of a so-called “spiral groove” extending on the medial side of the bone (evans & milner, 1993). comments. typical features of the above specimens are the presence of a primary sculpture on the maxilla, the nature of the dorsal ridge on the ilium and the lack of the dorsal protuberance. in pelodytes the ilium resembles the genus pelobates, but in the former a small dorsal protuberance is always present on the ilium (venczel & hír, 2013: fig. 64). family ranidae batsch, 1796 genus pelophylax fitzinger, 1843 pelophylax sp. fig. 4n. figure 4. anurans from the middle miocene of hidas, hungary. a-c: latonia seyfriedi, presacral vertebra (a), sacral vertebra (b) and ilium (c); d-k: palaeobatrachus sp., frontoparietal (d, e), maxillae (f, g), sphenethmoid (h), angulars (i, j) and humerus (k); l, m: pelobates sp., maxilla (l) and ilium (m); n: pelophylax sp., ilium. a, b, e, k – ventral views, c, m, n – lateral views, d, i, j – dorsal views, f, g – lingual views, h – anterior view, l – labial view. scale bar = 2 mm. g eo lo gi a c ro at ic a geologia croatica 77/120 referred material: one fragmentary left ilium (mmp.2023. 22.1.) description. ilium. the only specimen preserves the acetabular region and part of the iliac shaft. the anterior half of the acetabulum appears circular and delimits ventrally an extremely deep supraacetabular fossa. the slightly convex dorsal protuberance extends anteriorly to the supraacetabular fossa into the dorsal margin of the posterior part of the iliac shaft. the preacetabular region is reduced. comments. the preserved parts of the only specimen are closely similar to the so-called hybridogenetic green frogs, described under the name pelophylax (= rana) esculentus (rage & hossini, 2000, venczel, 2004, venczel & hír, 2013) from various middle miocene localities. class reptilia laurenti, 1768 order squamata oppel, 1811 family lacertidae oppel, 1811 lacertidae indet. referred material: one posterior fragment of a left maxilla (mmp.2023.23.1.), two fragmentary dentaries (mmp.2023.24.1.). description. maxilla. the specimen represents a small posterior part of the maxilla provided with a fragmentary facial process and seven tooth positions. the tooth crowns are cylindrical and bicuspid with a smaller anterior and a larger posterior cusp (fig. 5a). dentary. the dentary displays a relatively deep and dorsoventrally narrow subdental shelf, filled with a fine grained lightgrey coloured matrix. the labial surface is smooth with few nutritive foramina. the tooth crowns are cylindrical, and if the apical region is preserved, they display a weakly bicuspid condition (fig. 5b). comments. the specimens might have belonged to a small sized taxon, comparable in size to the living members of podarcis or zootoca. family anguidae gray, 1825 anguinae indet. fig. 5c-f referred material: one posterior fragment of a right dentary (mmp.2023.25.1.), one trunk vertebra (mmp.2023.26.1.). description. dentary. the specimen preserves a posterior dentary fragment with six tooth positions. the dental parapet is of relatively low height, whereas a medially projecting nearly horizontal crest may correspond to the contact surface of coronoid articulation. the tooth bases are widened mediolaterally, whereas the tooth crown is very worn apically with some trace of a mesiodistal carina. the labial surface is smooth and nearly flat with its ventral part broken off. trunk vertebra. the specimen is extremely small with an elongated centrum and displays a smooth ventral surface without any constriction. the cotyle is strongly flattened, the synapophyses are relatively small and the neural canal is enlarged and of roughly triangular shape. comments. the specimens despite their fragmentary nature (dentary) or small size (vertebra) appear reminiscent of ophisaurus (venczel & hír, 2013). however, based on the available material, a closer assignment is not possible. family colubridae oppel, 1811 colubridae indet. sp. 1 fig. 5g, h. referred material: seven fragmentary vertebrae (mmp. 2023.27.1-7). description. trunk vertebrae. the available specimens represent a large sized colubrid snake. the centrum length of the largest vertebra is 7.2 mm. unfortunately, the neural arch is broken off in all the examples. the main preserved characteristic is that the haemal keel is flattened and spatulate shaped. small subcotylar tubercles are present in some of the specimens. comments. large sized colubrids with somewhat similar morphology from the early late miocene of litke have been assigned by venczel & hír (2015) to “coluber” cf. caspioides, or to “coluber” pouchetii from the late middle miocene of felsőtárkány 3/2. and 3/10 localities (venczel & hír, 2013). figure 5. squamate reptiles from the middle miocene of hidas, hungary. a, b: lacertidae indet., maxilla (a) and dentary (b); c-f: anguinae indet, dentary (c, d) and trunk vertebra (e, f); g, h: colubridae indet. sp. 1, trunk vertebrae; i-k: colubridae indet. sp. 2, trunk vertebrae. a-c lingual views, d – lateral view, e – anterior view, f-h, j, k ventral views, i – dorsal view. scale bar = 2 mm. g eologia c roatica hir et al.: middle miocene (late badenian) microvertebrates from hidas, sw hungary 21 colubridae indet. sp. 2 fig. 5i-k. referred material: 20 fragmentary vertebrae (mmp.2023. 28.1-20). description. trunk vertebrae. the specimens are small sized, the centrum length never reaching 5 mm. the neural arch is moderately vaulted, the zygosphene, if preserved, has a shallowly convex anterior margin, whereas the paradiapohyses are differentiated into diapophyseal and parapophyseal portions of roughly equal length. the haemal keel of the trunk vertebrae is prominent and long, extending posteriorly into the vicinity of the condyle in the form of a narrow ridge. in some specimens the posterior part of the haemal keel is slightly flattened dorso-ventrally. comments. the morphology of the available specimens, especially those of the haemal keels display a wide range of variation, and therefore, we cannot exclude that the material contains more than one small sized colubrid taxon. class mammalia linnaeus, 1758 order rodentia bowdich, 1821 family gliridae thomas, 1897 subfamily glirinae thomas, 1897 genus myoglis baudelot, 1965 myoglis meini (de bruijn, 1966) table 1. myoglis meini data from hidas. locality: no. inv. position: l: w: figure: hidas mmp. 2022.6.1. p4 1.61 1.62 hidas mmp. 2022.5.1. m3 1.82 1.83 pl. 1f description. p4. it possesses a rectangular outline with rounded angles. the occlusal surface is flat. there are four main ridges: anteroloph, protoloph, metaloph, posteroloph. anteroloph has free ends in the lingual and labial margin, the other main ridges are fused in the postero-lingual angle (protocone). one additional ridge: the anterior centroloph, is situated between the lingual margin and the centre of the occlusal surface. the ends of this ridge are free. m3. it has a subtriangular outline. the occlusal surface is flat. the anterior margin is broad, the posterior one is rounded. the enamel of the posterior slopes of the ridges is wrinkled. the four main ridges are: anterolophid, metalophid, mesolophid, posterolophid. the anterolophid is transversal, the other main ridges are positioned diagonally. there are three secondary ridges: 1. anterior additional ridge (between the anterolophid and the metalophid on the lingual side), it has two short minor ridges on the anterior and the posterior sides; 2. a long, but low developed centrolophid on the posterior side of the metalophid; 3. a short posterior extra ridge between the mesolophid and the posterolophid on the lingual side. comments. the biochronological range of myoglis in europe extends from the early miocene to the late miocene (mn2 -mn10). in the pannonian basin the earliest occurrence is from szentendre (early mn6). the latest record is known from the richardhof-wald (mn10), vienna basin, austria. myoglis is a characteristic element of the microvertebrate faunas mirroring a humid climate and forested environment. van der meulen & de bruijn (1982) classified myoglis as a member of the “flat molar group” which has a mainly vegetarian diet. subfamily dryomyinae de bruijn, 1967 genus paraglirulus engesser, 1972 paraglirulus werenfelsi engesser, 1972 table 2. paraglirulus werenfelsi data from hidas. locality: no. inv. position: l: w: figure: hidas mmp. 2022. 7. 1 m2 1.15 1.22 pl. 1e description. m2. it has a rectangular outline. the occlusal surface is concave. the ornamentation on the lingual margin is weak. it has four main ridges and five secondary ridges. the main ridges are: anteroloph, protoloph, metaloph, posteroloph. all of them are labially connected to the continuous endoloph. the anteroloph and protoloph are labially fused. the labial end of the posteroloph is close to the metaloph, but there is no complete fusion. the extra ridges are as follows: 1. a long and centrally positioned anterior extra ridge having free ends between the anteroloph and the protoloph; 2. anterior centroloph having free lingual end, labial end is fused with protoloph; 3. a very long extra ridge between the centrolophs; the labial end fuses with endoloph, the lingual end reaches the base of the anterior centroloph on the labial margin, but a complete fusion is not developed; 4. posterior centroloph is with free lingual end and labial end is fused with metaloph; 5. a short extra ridge develops between the posterior centroloph and the metaloph has free ends; 6. a relatively long, centrally positioned extra ridge has free ends between the metaloph and the posteroloph. comments. paraglirulus werenfelsi is a frequent element of the middle miocene microvertebrate faunas. in the pannonian region the biochronological range of this species extends from the mn5 up to the mn10 zone. paraglirulus is regarded as a member of the group „gliridae ii,” having an arboreal-scansorial lifestyle (van dam & weltje, 1999). van der meulen & de bruijn (1982) classified paraglirulus as a member of the ”symmetrical molar goup”, which has a mainly vegetarian diet. family sciuridae fischer de waldheim, 1817 subfamily pteromyinae brandt, 1855 genus albanensia daxner-höck & mein, 1975 albanensia albanensis (major, 1893) table 3. albanensia albanensis data from hidas. locality: no. inv. position: l: w: figure: hidas mmp. 2022. 1. 1 m1 3.25 3.90 pl. 1a hidas mmp. 2022. 8. 1 p4 3.05 3.12 description. m1. it has a subrectangular outline with rounded lingual side, because of the convex lingual wall of the protocone. this lingual wall is crenulated and has two incisions. the lingual cingulum on the base of the protocone is weak. the anteroloph is a continuous ridge from the centre of the protocone up to the anterior margin of the paracone. this ridge has no minor cusps. the protoloph and metaloph converge on the labial side of the protocone in a v-shape. protoconule is incipient. protoloph is a continuous ridge (not having a „zigzag form” in the sense of daxner-höck, 2004) between the protocone and the paracone, but it bears short anteriorly and posteriorly directed additional ridges. the mesostyle crista on the posterior side of the paracone is well developed. mesostyle is absent. the metaloph connects the protocone, metaconule and metacone. it has a weak g eo lo gi a c ro at ic a geologia croatica 77/122 the protocone. a short secondary ridge (protoconule) is directed anteriorly from the lingual part of the protoloph into the anterosinus. the metaloph is broad, two cusps (metaconule) are incorporated into this ridge. the posteroloph is poorly developed related to the other ridges. in the deepest part of the sinuses the enamel is not crenulated. m3. it has a subtriangular outline, with rounded angles. the two main cusps are the protocone and the paracone. in the mesial surface there is the anteroloph, which extends from the protocone to the anterior surface of the paracone. the protoloph extends between the protocone and the paracone. anteroloph and the protoloph are transversal and parallel. a small protoconule is developed on the lingual part of the protoloph. hypocone is developed as a small cusp on the posterior slope of the protocone. the posterior slope of the paracone bears a weak mesostyle crista. the weakly developed posteroloph has a semicircular shape and closes the central basin. the surface of the central basin is crenulated by irregular secondary ridges. m1. it has a trapezoidal outline, the posterior width is larger than the anterior one. the four main cusps are situated in the four angles of the occlusal surface: protoconid (antero-labial), metaconid (antero-lingual), hypoconid (postero-labial), entoconid (postero-lingual). lower developed conulids are the mesostylid on the posterior slope of the metaconid and the mesoconid between the protoconid and the hypoconid. mesoconid is connected to the labial main cusps via the ectolophid. it bears a transversal enamel ridge which reaches the labial margin. the protoconid and the metaconid are connected by the anterolophid and the metalophid. the anterolophid is stronger and anteriorly protuberant. the metalophid is thinner. the two main anterior cusps and the ridges enclose the small trigonid basin. there is a deep notch between the mesostylid and the entoconid. the central part of the occlusal surface is occupied by a large talonid basin. this basin is posteriorly bordered by a posterolophid. hypoconulid is not developed. irregular secondary ridges start from the posterolophid and expand to the centre of the talonid basin. comments and discussion. forsythia is a middle-sized flying squirrel genus, which is extremely rare. referring to daxner-höck (2010) it has been found in the faunas of the mn 7+8 zone. de bruijn et al. (2003) described forsythia from the anatolian locality çandir (mn6). ziegler & fahlbusch (1986) classified forsythia aff. gaudryi from the early miocene mn4 localities of rembach and erkertshofen, which were later referred to aliveria luteyni by de bruijn (1999). forsythia evolved from the early miocene aliveria, which is the common ancestor of the genera forsythia and albanensia (de bruijn et al. 1980). in the pannonian basin forsythia has only been reported from the mn7+8 locality gratkorn (austria), where a complete lower toothrow was described by (daxnerhöck, 2010) and an m1-2 was reported from egerbocs (mn7+8, northern hungary) by hír (2001). family cricetidae rochebrune, 1883 subfamily cricetinae rochebrune, 1883 genus democricetodon fahlbusch, 1964 democricetodon freisingensis (fahlbusch, 1964) description. m1. anterocone has two units, but they are not divided. sulcus or groove are absent in the mesial surface. the lingual anteroloph reaches the base of the protocone and closes tendency for „zigzag” formation. hypocone is incipient. the metacone and metaconule have posterior ledges, but these extra ridges do not reach the posteroloph. the posteroloph is thin and bears minor anteriorly directed additional ridges. p4. it has a trapezoidal outline with rounded angles. anterior margin is narrower than the posterior one. on the mesial part of the crown there are two cusps: protoconid and metaconid. they are connected by two ridges: anterolophid and metalophid. the cusps and the ridges enclose the small trigonid basin. anteroconulid is not developed. an enamel ridge is developed on the posterior slope of the metaconid (on the lingual margin) reaching to the mesolophid. this latter element forms an incipient cusp. there is an incision between the mesolophid and the entoconid. the poorly developed mesoconid on the labial side is connected to the protoconid and the hypoconid by enamel ridges. posterolophid consists of a series of minor cusps. the surface of the talonid basin is crenulated. comments albanensia is a large sized flying squirrel. in the miocene of the pannonian basin three albanensia species are represented: a. sansaniensis, szentendre, hungary, hír (2019), hír & venczel (2018) a. albanensis, gratkorn, austria, daxner-höck (2010); mikófalva, hungary, hír (2019) a. grimmi (felsőtárkány 3/2, hungary, hír (2019); götzendorf, richardhof-wald, richardhof-golfplatz, austria, daxner -höck (2004); pezinok, slovakia, joniak (2016). a. sansaniensis is the oldest one (mn6), while a. grimmi is the youngest one (mn9, mn10). the systematic position of the albanensia population of rudabánya (mn9) is open to dispute. kretzoi & fejfar (2005) classified this population as a. grimmi, but the dimensions are smaller (hír 2019). daxner-höck (2010) defined the distinctive characters of a. albanensis as follows: smaller dimensions, lower and less crenulated loph(ids) and con(ids), smaller p4/p4, longer m3 with continuous and a small or absent hypoconulid, straight (not zigzag-shaped) protoloph and metaloph, absent or very short protoconule, small hypocone. the classification of the teeth from the hidas formation is based mainly on the dimensions and the incipient protoconule and hypocone. the protoloph is undoubtedly straight. the metaloph is disputed, but the “zigzag figure” is not typical. the lingual cingulum is weak. the albanensia genus became extinct in the early phase of the late miocene (mn10). the other flying squirrel genera (miopetaurista, neopetes, pliopetes, pliopetaurista, blackia) survived the “vallesian crisis” and occurred in central europe up to the pliocene (mn15 zone). forsythia gaudryi (gaillard, 1899) table 4. forsythia gaudryi data from hidas. locality: no. inv. position: l: w: figure: hidas mmp. 2022. 9. 1 m1-2 1.92 2.48 pl. 1b hidas mmp. 2022. 2. 1 m3 2.35 2.28 pl. 1c hidas mmp. 2022. 3. 1 m1 2.03 2.16 pl. 1d description. m 1-2. the occlusal surface has a subrectangular outline with a rounded and convex lingual surface. there are two small incisions in the convex lingual surface. the protoloph and the metaloph converge towards the labial margin of g eologia c roatica hir et al.: middle miocene (late badenian) microvertebrates from hidas, sw hungary 23 the protosinus. in a similar way the labial anteroloph reaches the base of the paracone and closes the anterosinus. a well-developed parastyle is frequent (5 of 9 specimens). anterolophule is branched (v-shaped) (8 of 9 specimens) or simple (only the lingual branch is found in 1 of 9 specimens). the two branches connect the anterior angle of the protocone and the two units of the anterocone. the labial spur of the anterolophule (anteromesoloph) is long, it reaches the labial margin, or the parastyle (8 of 9 specimens). in one case it is absent. protolophule is double (4 of 9 specimens) or only the posterior branch is present (5 of 9 specimens). paracone posterior spur is rare and remnant (short) (2 of 9 specimens). the long mesoloph is regular. it always reaches the labial margin. entomesoloph is absent. metalophule is short and posterior. a remnant anterior metalophule is found in 4 of 9 specimens, but it does not reach the hypocone, or the anterior arm of the hypocone. m2. lingual and labial arms of the anteroph reach the anterior base of the protocone and the paracone and close the anterosinus and the protosinus. the anterosinus is deeper. double protolophule is regular. mesoloph is long, reaches the labial margin (5 of 6 specimens), or short (1 of 6 specimens). entomesoloph is absent. a double metalophule is frequent (4 of 6 specimens). in two cases the anterior metalophule is a remnant and does not reach the hypocone or the anterior arm of the hypocone. m3. anterosinus and protosinus are closed. protosinus is shorter. protolophule is double. mesoloph is long and reaches the labial margin. entomesoloph is absent. hypocone and metacone are reduced. metalophule is anterior. m1. the anteroconid consists of two or three units, but they are either not divided, or only superficial grooves are found in the mesial surface in the juvenile unworn molars. the labial anterolophid reaches the anterior base of the protoconid and closes the protosinusid. lingual anterolophid is not developed and the anterosinusid is open. anterolophulid is branched (v-shaped). the lingual branch runs to the lingual unit of the anteroconid. the labial branch runs to the labial unit of the anteroconid (4 of 8 specimens) or to the labial anterolophid (4 of 8 specimens). the long mesolophid is regular (reaches the lingual margin). the ectomesolophid can be complete and long (5 of 8 specimens) (it connects the anterior arm of the hypoconid and the labial margin of the toothcrown), or it can be short (3 of 8 specimens) (no connection with the anterior arm of the hypoconid). m2. the labial anterolophid is well developed, reaches the anterior base of the protocone and closes the protosinusid. the lingual anterolophid is short and closes the small anterosinusid. the long mesolophid is regular (as in m1). the ectomesolophid is short, never reaches the anterior arm of the hypoconid. posterosinusid is relatively wide and closed by the posterolophid. m3. anterolophids are developed as in m2. mesolophid is long. a complete ectomesolophid is found in one case. in the other molar it is absent. entoconid is reduced. posterosinusid is ellipsoid and closed by the posterolophid. comments. the abstract of the d. freisingensis original diagnosis (fahlbusch, 1964) is as follows: well developed and long labial eperon of the anterolophule of m1, double protolophule is frequent in m2, less frequent in m1; anteroconid is wide and indented in m1. the possibility of the distinction of d. gaillardi and d. freisingensis is a subject of a long discussion. fahlbusch (1964), baudelot (1972) and heissig (1995) underlined the similarity of the two species. heissig (1995) realized the presence of the doubled anterolophulid of m1 in the type material of d. freisingensis (giggenhausen) and the simple anterolophulid in the type material of d. gaillardi (steinheim). referring to maridet & sen (2012) the distinctive characters among others include: the labial margin of the m1 the paracone and metacone are in line in d. gaillardi, but in d. freisingensis the metacone is situated in a more labial position. these observations can be useful in samples of statistically significant quantities. taking into consideration that the debate concerning the synonymy of d. gaillardi/d. freisingensis is not closed, we do not follow the proposal of maridet (2003). the earliest occurrence of d. freisingensis is described in sansan (type fauna of the mn6 zone) (maridet 2003). the numeric age of sansan is the subject of a long debate. some published data are as follows: fejfar & heinrich (1997): 12.5 ma, krijgsman et al. (1994, 1996): 12.7-13.0 ma, kälin (1997): 13.9 ma, kälin & kempf (2009): 14.1 ma, sen (1997): 15.2-15. ma, steininger (1999): the top of mn6 at 13.5 ma, base of c5abn palaeomagnetic chron. we presume that the age between 13.9-14.2 ma is the most probable, because it is in line with the first occurrence of d. freisingensis in the swiss molasse: niderwis, which is dated to 14.1 ma by kälin & kempf (2009). in the bavarian molasse the fad of this species table 5. democricetodon freisingensis data from hidas. locality: no. inv. position: l: w: figure: hidas mmp. 2022. 10. 1 m1 2.21 1.41 hidas mmp. 2022. 11. 1 m1 2.23 1.46 hidas mmp. 2022. 12. 1 m1 2.02 1.34 hidas mmp. 2022. 14. 1 m1 2.21 1.46 pl. 1g hidas mmp. 2022. 15. 1 m1 2.24 1.34 hidas mmp. 2022. 16. 1 m1 2.07 1.18 hidas mmp. 2022. 17. 1 m1 2.04 1.48 hidas mmp. 2022. 18. 1 m1 fr. 1.41 hidas mmp. 2022. 19. 1 m1 fr. 1.40 hidas mmp. 2022. 20. 1 m2 1.61 1.43 hidas mmp. 2022. 21. 1 m2 1.67 1.48 hidas mmp. 2022. 22. 1 m2 1.71 1.60 hidas mmp. 2022. 23. 1 m2 1.61 1.47 hidas mmp. 2022. 24. 1 m2 1.50 1.32 hidas mmp. 2022. 25. 1 m2 1.57 1.40 hidas mmp. 2022. 28. 1 m3 1.26 1.30 hidas mmp. 2022. 29. 1 m1 1.85 1.32 hidas mmp. 2022. 30. 1 m1 1.90 1.33 hidas mmp. 2022. 31. 1 m1 1.76 1.22 hidas mmp. 2022. 32. 1 m1 1.96 1.40 hidas mmp. 2022. 33. 1 m1 2.03 1.33 hidas mmp. 2022. 34. 1 m1 1.92 1.41 hidas mmp. 2022. 35. 1 m1 1.97 1.33 hidas mmp. 2022. 36. 1 m1 1.90 1.26 hidas mmp. 2022. 40. 1 m2 1.76 1.43 pl. 1m hidas mmp. 2022. 41. 1 m2 1.81 1.47 hidas mmp. 2022. 42. 1 m2 1.75 1.39 hidas mmp. 2022. 43. 1 m2 1.74 1.33 hidas mmp. 2022. 44. 1 m2 1.75 1.44 hidas mmp. 2022. 45. 1 m2 1.68 1.39 hidas mmp. 2022. 49. 1 m2 1.72 1.43 hidas mmp. 2022. 47. 1 m3 1.71 1.30 pl. 1n hidas mmp. 2022. 46. 1 m3 fr. 1.68 g eo lo gi a c ro at ic a geologia croatica 77/124 is dated to 14.2 ma by prieto & rummel (2016). the latest occurrences of d. freisingensis are documented in the mn8 faunas of southern germany and switzerland containing deperetomys. these 12 faunas are listed by prieto (2012). the numerical age of them is estimated between 13.8 and 13.3 ma (kälin & kempf, 2009). in the pannonian basin democricetodon cf. freisingensis was reported from mátraszőlős (hír & kókay 2004, 2011), northern hungary. the morphology of the mátraszőlős finds is identical to the type population of d. freisingensis from giggenhausen (after the description of maridet, 2003), but the dimensions are rather large. the mátraszőlős localities were correlated with the latest part of the badenian (hír et al., 2017). the report of d. freisingensis from subpiatră by hír & venczel (2005) is not reliable because the classification of the material was emended as democricetodon brevis (hír, 2020). the occurrence of the species in the mn9 fauna of rudabánya (kretzoi & fejfar, 2005) is mysterious. the morphology is undoubtedly referable to d. freisingensis, but the main dimensions are smaller and the biochronological position is late mn9. democricetodon sp. table 6. democricetodon sp. data from hidas. locality no. inv. position: l: w: figure: hidas mmp. 22. 13. 1 m1 1.83 1.18 pl. 1h hidas mmp. 22. 26. 1 m2 1.47 1.25 hidas mmp. 22. 37. 1 m1 1.62 1.13 pl. 1l hidas mmp. 22. 38. 1 m1 1.51 0.99 hidas mmp. 22. 39. 1 m1 1.67 1.19 description. m1. anterocone is undivided. the anterior surface is smooth, and the sulcus or groove are absent. the labial part is wider, the lingual part is narrower and continued in a lingual anteroloph. it reaches the base of the protocone and closes the protosinus. the labial anteroloph is situated between the labial base of the anterocone and the anterior base of the protocone. anterolophule extends from the centre of the anterocone to the anterior angle of the protocone. the anterolophule bears two short and slightly developed labial eperons, both of them reach the anterior base of the paracone. protolophule is posterior and connected to the centroloph close to the posterior angle of the protocone. mesoloph is moderately developed. the tip of the mesoloph reaches the anterior base of the metacone. metalophule is short and connected to the posteroloph. m2. the lingual and labial anteroloph are both well developed and both reach the anterior surfaces of the protocone and the paracone closing the protosinus and the anterosinus. protosinus is shallow, anterosinus is deeper. protolophule is double. mesoloph is long and terminates in a mesostyle. metalophule is short and connected to the posteroloph. m1. anteroconid is simple. the mesial surface is smooth. labial anterolophid is well developed and reaches the anterior base of the protoconid closing the protosinusid. lingual anterolophid is absent. the lingual base of the anteroconid and the anterior base of the metaconid are close to each other and shut the anterosinusid. the anterolophulid-metalophulid-anteroconid structure is special. anterolophulid is absent (2 of 3 specimens) or very short (1of 3 specimens). metalophulid is connected to the anteroconid (3 of 3 specimens). mesolophid is long and terminates in a mesostylid. sinusid is closed by a cingulum. posterolophid reaches the posterior base of the entoconid at a low level and the posterosinusid is not closed. comments and discussions. initial observation of the metrical and morphological characteristics of the small sized democricetodon finds of hidas suggests they are close to democricetodon mutilus. but in the territory of the upper freshwater molasse (southern germany and switzerland) no particular precedents exist for the coexistence of d. freisingensis and d. mutilus. the latter species has a long biochronological range from the late mn4 to the end of mn6 (maridet, 2003, kälin & kempf, 2009; prieto & rummel, 2016). the younger (mn8) occurrences are disputed. these are as follows: giggenhausen. there are five molars published. they were first classified as d. cf. mutilus nov. subsp. by fahlbusch (1964). among the morphological characteristics the wide anterocone in the m1 and the presence of ectomesolophid is mentioned in m1 by maridet (2003). he underlined the close relationship with d. cf. mutilus from vermes 2. kleineisenbach. the three molars of d. cf. mutilus reported were regarded as the descendant of d. mutilus by fahlbusch (1964). referring to the description of prieto (2007) the frequent lingually directed anterolophulids in m1 and the frequent interrupted ridges are characteristic in the kleineisenbach material. vermes 2. the material consists of one lower toothrow and an m3. it was classified as d. cf. mutilus (engesser et al. 1981). in more recent descriptions (maridet, 2003, prieto, 2007) the occurrence of an enamel ridge in the mesial surface of the m1, the poorly developed ectomesolophids, the lingually directed anterolophulids in m1 are mentioned. according to prieto (2007) the vermes 2 small sized democricetodon can be classified as a new species. maridet (2003) drew a different conclusion: he confirmed the original classification. the biochronological position of vermes 2 is the subject of a long debate. the list of different concepts is the following: aguilar (1982): mn 7+8; engesser et al. (1981): mn8; kälin (1997): mn5; kälin & kempf (2009): mn5; heissig (1997): mn5; maridet (2003): mn 7+8; prieto (2007): mn8. the democricetodon cf. mutilus materials of the three localities discussed above are limited, as is the sample from hidas. nevertheless, we can conclude that a close relationship of the hidas finds with d. cf. mutilus from giggenhausen, kleineisenbach and vermes 2 is not probable, because some characteristic morphological elements of the three upper freshwater molasse assemblages are not found in hidas, e.g., enamel ridge in the mesial surface of m1, lingually directed anterolophulids in m1, ectomesolophids in lower molars, and interrupted ridges. megacricetodon minor (lartet, 1851) table 7. megacricetodon data from hidas. locality: no. inv. position: l: w: figure: hidas mmp. 2022. 27.1 m2 1.34 1.12 hidas mmp. 2022. 5.1 m2 1.29 0.98 description. m2. it has a rectangular outline, which is smaller and more elongated than the m2s of the democricetodon species. the lingual and labial arms of the anteroloph reach the anterior base of the protocone and the paracone and close the anterosinus and the protosinus. protosinus is shallow, anterosinus is deeper. protolophule is posterior. mesoloph is short and reaches the anterior surface of the metacone. paracone posterior spur is g eologia c roatica hir et al.: middle miocene (late badenian) microvertebrates from hidas, sw hungary 25 short and weak. the lingual and labial sinuses are closed by the weakly developed cingulums. metalophule is transversal, it starts from the centre of the hypocone. posteroloph reaches the posterior base of the metacone. m2. it has a rectangular outline, which is smaller and more elongated than the m2s of the democricetodon species. in the mesial surface the labial anterolophid is complete and closes the anterosinusid. lingual anterolophid is short, no protosinusid. mesolophid is short and reaches the posterior base of the metaconid. posterolophid reaches the posterior base of the entoconid and closes the posterior sinusid. lingual sinusid is open, labial sinusid is closed by a cingulum. the sample is modest, but it is enough for the classification. megacricetodon minor is a frequent and regular element of the middle miocene vertebrate faunas in the pannonian basin from the mn5 to the mn7+8 zones. only minor morphological differences are visible in this series of megacricetodon minor populations (hír pers. obs.). plate 1. occlusal surfaces of the studied rodent molars. all are figured in the left side position. the originally right-side molars are graphically reversed. scale bar = 1mm taxa position: no. inv. a. albanensia albanensis (major, 1893), m1, mmp. 2022. 1. 1. reversed b. forsythia gaudryi (gaillard, 1899), m1-2, mmp. 2022. 9. 1. reversed c. forsythia gaudryi (gaillard, 1899), m3, mmp. 2022. 2. 1. d. forsythia gaudryi (gaillard, 1899), m1, mmp. 2022. 3. 1. e. paraglirulus werenfelsi engesser, 1972 m2, mmp. 2022. 7. 1. reversed f. myoglis meini (de bruijn, 1966), m3, mmp. 2022. 5. 1. reversed g. democricetodon freisingensis, (fahlbusch, 1964), m1, mmp. 2022. 14. 1. reversed h. democricetodon sp., m1, mmp. 2022. 13.1. i. democricetodon freisingensis (fahlbusch, 1964), m2, mmp. 2022. 20. 1. j. democricetodon sp., m2, mmp. 2022. 26. 1. k. democricetodon freisingensis (fahlbusch, 1964), m1, mmp. 2022. 33. 1. reversed l. democricetodon sp., m1, mmp. 2022. 37. 1. m. democricetodon freisingensis (fahlbusch, 1964), m2, mmp. 2022. 40. 1. n. democricetodon freisingensis (fahlbusch, 1964), m3, mmp. 2022. 47. 1. reversed g eo lo gi a c ro at ic a geologia croatica 77/126 5. discussion 5.1. the age of the fauna the coexistence of albanensia albanensis, forsythia gaudryi and democricetodon freisingensis is referable to the mn7+8 zone (13.5–11.1 ma, steininger 1999) and a late badenian age. similar assemblages in the pannonian basin are the faunas from mátraszőlős with d. cf. freisingensis., d. brevis, albanensia sp. and a rich late badenian mollusc fauna (hír & kókay 2004, 2011). the microvertebrate material of hidas strengthens the earlier ideas on the late badenian age of the hidas formation in the mecsek mts., which has been estimated as between 13.3–13.7 ma (selmeczi et al., 2023), and brackets the age of the unit to ~13.5–13.3 ma. 5.2. palaeoenvironmental reconstruction the fossil lissamphibians and reptiles from hidas appear as a low diversity assemblage, and each taxon is represented by only a few specimens, with the exception of the alytid frog latonia seyfriedi, which is the most abundant species in the oryctocoenosis. a proportion of the recorded amphibians represent aquatic (e.g., palaeobatrachus) or semiaquatic forms (e.g., pelophylax), while other taxa probably preferred periaquatic environments (lissotriton sp., latonia seyfriedi). the sedimentary facies of the fossilbearing layer – composed of lime mud, lacking bedding, with a crumbly structure – together with the enclosed freshwater gastropod fauna, indicates a shallow pond or a paludal environment, where the listed aquatic herpetofauna could find a suitable habitat. the additional vertebrate fossils had probably been washed into the pond from the immediate surroundings. the pelobatid frog (pelobates sp.), based on the preference of recent taxa, might have been a burrower in the aerated sandy soils along lakes or rivers. the small number of indetermined lizards and snakes occurred probably around these aquatic habitats. nevertheless, the lack of natricinae snakes (which prefer freshwater) is noteworthy, as well as the absence of elapids and viperids. from the rodent taxa, glirids and flying squirrels as well as democricetodon and megacricetodon indicate humid arboreal vegetation around the site (weerd & daams 1978, daams et al. 1988). additionally, the cited presence of the alligatoroid crocodylian diplocynodon (vadász 1935, kordos 1985), according to marckwick (1998), indicates a relatively mild palaeoclimate: a mean annual temperature of at least 15.3 °c with a mean temperature of the coldest month of at least 5.5 °c. this shows that although the hidas formation was deposited after the miocene climatic optimum (17–15 ma, zachos et al. 2001), the climate was still warm enough for subtropical taxa to inhabit the area. in fact, the accumulation of the formation took place just before the miocene warm period ended in central europe (~14–13.5 ma), with an increase in seasonality, growing oscillations in humidity and the extinction of numerous thermophilic groups (böhme 2003). 5.3. palaeogeographical relationships it was by the end of the middle miocene that the lithospheric units comprising the basement of the pannonian basin reached a geographical configuration that more or less corresponds to the present-day situation (horváth et al., 2006). at the time of the accumulation of the hidas formation, the palaeogeography of the pannonian basin is described as an archipelago in the central paratethys (hámor, 2001; kováč et al., 2007, 2017, fig. 4; nagymarosy & hámor, 2012, fig. 3.16), with the mecsek mts. being one of the islands. before the studied time period, around the end of the early badenian, reconstructions indicate that sea troughs of bathyal depths existed in the mecsek area, with connections towards the mediterranean (báldi et al., 2002, szabó et al., 2022). the faunal assemblage of hidas desribed here shows no characteristics typical of insular faunas, e.g., gigantism or endemism. most of the taxa are identical to those reported from coeval assemblages in north hungary and western romania (hír et al., 2016, 2017, 2019). this means that the mecsek area had some ecological connections with the northern and eastern part of the pannonian basin, and the sea branches or embayments of the central paratethys within the archipelago did not form a barrier against the distribution of microvertebrates. considering the above cited palaeogeographic information, the corridor could have been located towards the ne from the me csek mts., across the elevated basement blocks of central hungary shown in nagymarosy & hámor (2012). 6. conclusions the fossil microvertebrate material of hidas is modest, but it allows some conclusions to be drawn from the data. the fauna and the enclosing sediment indicates varied environments, lakes or swamps surrounded by forests. the biochronological position of the fauna can be classified as mn 7+8 based on the presence of d. freisingensis, forsythia gaudryi and albanensia albanensis. together with the badenian molluscs of the formation, this can be correlated to the late badenian in the regional, central paratethys stratigraphy, or to the lower serravallian in standard global stratigraphy. this interpretation is in accordance with the earlier classifications based on the stratigraphic position and the mollusc fauna. the studied material represents the first middle miocene microvertebrate fauna from southern hungary. the rodent taxa described herein are well known from the middle miocene faunas of northern hungary and from the upper freshwater molasse of southern germany and switzerland. from these findings we can conclude that ecologically, the mainland of the mecsek region was not an isolated territory during this time period, and some passable corridors (land bridges) existed from here towards other parts of the pannonian basin that allowed faunal exchange. acknowledgement the authors would like to express their sincere thanks for the monetary help of the nka (hungarian national cultural fund) géniusz program no. 650132/00031, the otka/nkfih project 138638 and the hungarian academy of science’s grant for the support of researchers raising children. we say thanks to mr. ferenc wekler, landowner of the locality for his kind permission for the fieldwork, and to the late ildikó selmeczi for discussions. at last but not least we have to express our thanks for the lecturers of the manuscript. references aguilar, j. (1982): contributions à l’étude des micromammifères du gisement miocène supérieur de montredon (hérault-2). les rongeurs.− palaeovertebrata, 12, 75–140. báldi, k., benkovics, l. & sztanó, o. (2002): badenian (middle miocene) basin development in sw hungary: subsidence history based on quantitative paleobathymetry of foraminifera.‒ international journal of earth sciences, 91, 490–504. doi: 10.1007/s005310100226 baranyai, d. (2010): hidasi középső-miocén otolithok összehasonlító vizsgálata [a comparative study of middle miocene otoliths from hidas – in hungarian].‒ hungarian student scientific competition paper, eger, 42 p. baudelot, s. (1965): complément à l’étude de la faune des rongeurs de sansan: les gliridés.‒ bull. soc. géol. france, 7, 758–764. doi: 10.2113/gssgfbull.s7-vii.5.758 g eologia c roatica hir et al.: middle miocene (late badenian) microvertebrates from hidas, sw hungary 27 baudelot, s. (1972): etude des chiroptéres, insectivores et rongeurs du miocéne de sansan (gers).‒ thése, toulouse, 496, 364 p. biton, r., geffen, e., vences, m., cohen, o., bailon, s., rabinovich, r., malka, y., oron, t., boistel, r., brumfeld, v. & gafny, s. (2013): the rediscovered hula painted frog is a living fossil.‒ nature communications 4, e1959. doi: 10.1038/ncomms2959 böhme, m. (2003): the miocene climatic optimum: evidence from ectothermic vertebrates of central europe.‒ palaeogeography, palaeoclimatology, palaeoecology, 195, 389–401. doi: 10.1016/s0031-0182(03)00367-5 bohnné havas, m. (1973): a keleti mecsek torton mollusca faunája [tortonian mollusc fauna of the mecsek mountains].‒ annals of the geological institute of hungary, 53/4, 218 p. csepreghyné-meznerics, i. (1950): a hidasi (baranya m.) tortonai fauna [the tortonian fauna of hidas (baranya county) – in hungarian].‒ annals of the geological institute of hungary, 39/2, 3–114. cuenca-bescos, g. (1988): revision de los sciuridae del aragoniense y del rambliense en la fossa de calatayud-montalban.− scripta geologica, 87, 1–115. daams, r. (1981): the dental pattern of the dormice dryomys, myomimus, microdyromys and peridyromys.‒ utrecht micropaleontological bulletins, special publications, 3, 115 p. daams, r. (1985): glirinae (gliridae, rodentia) from the type area of the aragonian and adjacent areas (provinces of teruel and zaragoza, spain).‒ scripta geologica, 77, 1–20. dams, r., freudenthal, m. & van der meulen, a. (1988): ecostratigraphy of micromammal faunas from the neogene of spain.‒ scripta geologica, special issue, 1, 287–302. daxner-höck, g. (2004): flying squirrels (pteromyinae, mammalia) from the upper miocene of austria.‒ annalen des naturhistorischen museums in wien, serie a, 106, 387–423. daxner-höck, g. (2010): sciuridae, gliridae and eomyidae (rodentia, mammalia) from the middle miocene of st. stefan in the gratkorn basin (styria, austria).‒ annalen des naturhistorischen museums in wien, 112a, 507–536. daxner-höck, g. & höck, e. (2015): catalogus fossilium austriae. band 4: rodentia neogenica.‒ verlag der österreichischen akademie der wissenschaften, 158 p. doi: 10.2307/j.ctt1vw0qvk de bruijn, h. (1999): superfamily sciuroidea.‒ in: rössner, g. & heissig, k. (eds.): the miocene land mammals of europe, verlag dr. friedrich pfeil, münchen, 271– 280 p. de bruijn h., meulen van der, a. & katsikatsos, g. (1980): the mammals from the lower miocene of aliveri (island of evia, greece). 1. the sciuridae.‒ in: proceedings of the koninklijke nederlandse akademie van wetenschappen, ser. b, 83, 241–261. de bruijn, h., van den hoek ostende, l., kristkoiz-boon, e., rummel, m. theocharopoulos, c. & ünay, e. (2003): rodents, lagomorphs and insectivores, from the middle miocene hominoid locality of çandir (turkey).‒ courier forschungs-institut senckenberg, 240, 51–87. engesser, b., matter, a. & weidmann, m. (1981): stratigraphie und säugetierfaunen des mittleren miozäns von vermes (kt. jura).‒ eclogae geologicae helvetiae, 74/3, 893–952. estes, r. (1981): encyclopedia of paleoherpetology, gymnophiona, caudata.‒ in: wellnhofer, p. (ed.), handbuch der paläoherpetologie (encyclopedia of paleoherpetology), part 2. gustav fischer verlag, stuttgart and new york, 115 p. evans, s.e. & milner, a.r. (1993): frogs ans salamanders from the upper jurassic morrison formation (quarry nine, como bluff) of north america.‒ journal of vertebrate paleontology, 13, 24–30. fahlbusch, v. (1964): die cricetiden (mamm.) der oberen süsswasser-molasse bayerns.− bayerische akademie der wissenschaften, matematisch-naturwissenschaftliche klasse, abhandlungen, neue folge, 118, 1–136. fejfar, o., heinrich, w. & lindsay, e. (1997): updating the european neogene rodent biochronology.‒ in: aguilar j., legendre s. & michaux j. (eds.): actes de congrès biochrom’97, mémoires et travaux école pratique des hautes études de l’institut de montpellier, 21, 563–565. georgalis, g. l., villa, a., ivanov, m., vasilyan, d. & delfino, m. (2019): fossil amphibians and reptiles from the neogene locality of maramena (greece), the most diverse european herpetofauna at the miocene/pliocene transition boundary.‒ palaeontologia electronica, 22.3.68, 1–99. doi: 10.26879/908 hámor, g. (2001): miocene palaeogeography of the carpathian basin. explanatory notes to the palaeogeographic maps of the carpathian basin 1: 3 000.000.‒ hungarian geological institute, 71 p. heissig, k. (1995): die entwicklung der grossen democricetodon -arten und die gattung collimys (cricetidae, mamalia) im späten mittelmiozän.‒ mitteilungen der bayerischen staatsasammlung für paläontologie und historische geologie, 35, 87–108. heissig, k. (1997): mammal faunas intermediate between the reference faunas of mn4 and mn6 from the upper freshwater molasse of bavaria.− actes du congrès biochrom’97, mém. trav. e.p.h.e. inst. montpellier, 21, 537–546. herre, w. (1955): die fauna der miozänen spaltenfüllung von neudorf a.d. march (scr).‒ sitzber. akad. wiss. math. naturwiss. kl., abt a, 164, 783–803. hír, j. (2001): new middle miocene rodent faunas from northern hungary.− lynx (praha) n. s., 32, 107–122. hír, j. (2019): the albanensia finds from hungary and romania.‒ fragmenta palaeontologica hungarica, 36, 1–24. doi:10.17111/fragmpalhung.2019.36.1 hír, j. (2020): the rodent faunas of the middle miocene palaeovertebrate localities in the pannonian basin (mammalia, rodentia).‒ manuscript, thesis, municipal museum of pásztó, 1–285. hír, j. & kókay, j. (2004): middle miocene molluscs and rodents from mátraszőlős (mátra mountains, hungary).− fragmenta palaeontologica hungarica, 22, 83–97. hír, j. & kókay, j. (2011): late badenian (mn 7/8) molluscs and rodents from mátraszőlős 3 (northern hungary).− fragmenta palaeontologica hungarica, 29, 69–78. hír, j., codrea, v. & prieto, j. (2019): two new early sarmatian s.str. (latest middle miocene) rodent faunas from the carpathian basin.– palaeobiodiversity and palaeoenvironments, 99/3, 527–543. doi:10.1007/s12549-019-00399-y pbpe-d19-00003r1 hír, j. & venczel, m. (2005): new middle miocene vertebrate localities from subpiatră (bihor district, romania).‒ acta palaeontologica romaniae, 5, 211–221. hír, j. & venczel, m. (2018): a preliminary report on the first results of the reexcavation of the middle miocene palaeovertebrate locality szentendre, cseresznyésárok (hungary, pest county).‒ nymphaea, folia naturae bihariae, 45, 35–80. hír, j., venczel, m., codrea, v., angelone, ch., van den hoek ostende, l., kirscher, u. & prieto, j. (2016): badenian and sarmatian s. str. from carpathian area: overview and ongoing research on hungarian and romanian small vertebrate evolution.‒ comptes rendus palevol., 15, 863–875. doi:10.1016/j.crpv.2016.08.001. hír, j., venczel m., codrea v., rössner g., angelone ch., van den hoek ostende, l., rosina, v., kirscher, u. & prieto, j. (2017): badenian and sarmatian s.str. from the carpathian area: taxonomic notes concerning the hungarian and romanian small vertebrates and report on the ruminants from the primate bearing felsőtárkány basin.− comptes rendus palevol., 16, 312–332. doi: 10.1016/j.crpv.2016.11.006 horváth, f., bada, g., szafián, p., tari, g., ádám, a. & cloething, s. (2006): formation and deformation of the pannonian basin: constraints from observational data.– in: gee, d.g. & stephenson, r.a. (eds.): european lithosphere dynamics, geological society, london, memoirs 32, 191–206. doi: 10.1144/gsl.mem.2006.032.01.11 hossini, s. (1993): a new species of latonia (anura, discoglossidae) from the lower miocene of france.‒ amphibia-reptilia, 14, 237–245. doi: 10.1163/156853893x00435 ivanov, m. (2008): early miocene amphibians (caudata, salientia) from the mokrá – western quarry (czech republic) with comments on the evolution of early miocene amphibian assemblages in central europe.‒ geobios, 41, 465–492. doi: 10.1016/j.geobios.2007.11.004 joniak, p. (2016): upper miocene rodents from pezinok in the danube basin, slovakia.− acta geologica slovaca, 8/1, 2–17. kälin, d. (1997): eomyops hebeiseni n. sp., a new large eomyidae (rodentia, mammalia) of the upper freshwater molasse of switzerland.− eclogae geologicae helvetiae, 90/3, 629–637. kälin, d. & kempf, o. (2009): high-resolution stratigraphy from the continental record of the middle miocene northern alpine foreland basin of switzerland.− neues jahrbuch für geologie und paläontologie, 254/1–2, 177–235. doi: 10.1127/00777749/2009/0010 kordos, l. (1985): a magyarországi eggenburgi – szarmata képződmények szárazföldi gerinces maradványai, biozonációja és rétegtani korrelációja [terrestrial vertebrate remains from the eggenburgian to sarmatian of hungary: biozonation and stratigraphic correlation].‒ annual report of the geological institute of hungary on 1983, 157–166. kordos, l. & solt, p. (1984): a magyarországi miocén tengeri gerinces faunaszintek vázlata (an outline of hungary’s miocene marine vertebrate faunal horizons).‒ annual report of the geological institute of hungary on 1982, 347–353. kováč, m., andreyeva-grigorovich, a., bajraktarević, z., brzobohatý, r., filipescu, s., fodor, l., harzhauser, m., nagymarosy, a., oszczypko, n., pavelić, d., rögl, f., saftić, b., sliva, l. & studencka, b. (2007): badenian evolution of the central paratethys sea: paleogeography, climate and eustatic sea-level changes.‒ geologica carpathica 58/6, 579–606. kováč, m., hudačková, n., halásová, e., kováčová, m., holcová, k., oszczypko-clowes, m., báldi, k., less, gy., nagymarosy, a., ruman, a., klučiar, t. & jamrich, m. (2017): the central paratethys palaeoceanography: a water circulation model based on microfossil proxies, climate, and changes of depositional environment.‒ acta geologica slovaca, 9/2, 75–114. g eo lo gi a c ro at ic a geologia croatica 77/128 kováč, m., halásová, e., hudáčková, n., holcová, k., hyžný, m., jamrich, m. & ruman, a. (2018): towards better correlation of the central paratethys regional time scale with the standard geological time scale of the miocene epoch.– geologica carpathica, 69/3, 283–300. doi: 10.1515/geoca-2018-0017 kretzoi, m. & fejfar, o. (2005): sciurids and cricetids (mammalia, rodentia) from rudabánya.− palaeontographia italica, 90, 113–148. krijgsman, w., langereis, c., daams, r. & meulen van der, a. (1994): magnetostratigraphic dating of middler miocene climate change in the continental deposits of the aragonian type area in the calatayud-teruel basin (central spain).‒ earth and planetary science letters, 128, 513–526. krijgsman, w., garcés, m., langereis, c., daams, r., meulen van der, a., agustí, j. & cabrera, l. (1996): a new chronology for the middle to late miocene continental record in spain.‒ earth and planetary science letters, 142, 367–380. 10.1016/0012-821x(96)00109-4 maridet, o. (2003): révision du genre democricetodon (mammalia, rodentia, cricetinae) et dynamique des faunes de rongeurs du néogène d’europe occidentale: évolution, paléobiodiversité et paléobiogéographie.‒ thèse université claude bernard, 252 p. maridet, o. & sen, s. (2012): les cricetidae (rodentia) de sansan.– in: peigné s. & sen s. (eds.): mammiféres de sansan.− muséum national d’histoire naturelle, 203, 26–95. marković, z. & milivojević, m. (2010): the neogene small mamals of serbia –collection methods and results.‒ bulletin of the natural history museum in beograd, 3, 105–114. markwick, p.j. (1998): fossil crocodilians as indicators of late cretaceous and cenozoic climates: implications for using palaeontological data in reconstructing palaeoclimate.‒ palaeogeography, palaeoclimatology, palaeoecology, 137, 205–271. doi: 10.1016/s0031-0182(97)00108-9 mckena, m. & bell, s. (1997): classification of mammals: above the species level.− columbia university press, new york, 1–631 p. mein, p. & freudenthal, m. (1971): les cricetidae (mammalia, rodentia) du néogène moyen de vieux-collonges. partie 1: le genre cricetodon lartet, 1851.‒ scripta geologica, 5, 1–51. miklas, p. (2002): die amphibienfauna (amphibia: caudata, anura) der obermiozänen fundstelle götzendorf an der leitha (südliches wiener becken, niederösterreich). ‒annalen des naturhistorischen museums in wien, 103 (a), 161–211. nagymarosy, a. & hámor, g. (2012): genesis and evolution of the pannonian basin.in: haas j. (ed.) 2012: geology of hungary. springer, heidelberg, 149–198. prieto, j. (2007): kleinsäuger-biostratigraphie und paläoökologie des höheren mittelmiozäns (mn8) bayerns: spaltenfüllungen der frankischen alb und lokalitäten der oberen süβwassermolasse im vergleich.− dissertation zur erlangung des doktorgrades (dr. rer. nat.) an der fakultät für geowissenschaften der ludwig-maximilians-universität münchen, 1–213 p. prieto, j. (2012): comments on the morphologic and metric variability in the cricetid rodent deperetomys hagni (fahlbusch, 1964) from the middle miocene of south germany.‒ zitteliana, a52, 71–77. prieto, j. & rummel, m. (2016): some considerations on small mammal evolution in southern germany, with emphasis on late burdigalian-earliest tortonian (miocene) cricetid rodents.− comptes rendus palevol, 15, 837–854. doi: 10.1016/j.crpv.2016.08.002 rage, j.-c. & hossini, s. (2000): les amphibiens du miocène moyen de sansan.– in : ginsburg, l. (ed.): la faune miocène de sansan et son environnement. mémoires du muséum national d’histoire naturelle, 183, 177–217. roček, z. (1994): taxonomy and distribution of tertiary discoglossids (anura) of the genus latonia v. meyer, 1843.‒ geobios, 27, 717–751. doi: 10.1016/s00166995(94)80058-8 roček, z., rage, j.c. & venczel, m. (2021): fossil frogs of the genus palaeobatrachus (amphibia: anura).‒ abhandlungen der senckenberg gesellschaft für naturforschung, 575, 1–151. sanchíz, b. (1998a): vertebrates from the early miocene lignite deposits of the opencast mine oberdorf (western styrian basin, austria): 2. amphibia.‒ annalen des naturhistorischen museums in wien 99a, 13–29. sanchíz, b. (1998b): salientia.– in: wellnhofer, p. (ed.): handbuch der paläoherpetologie. (encyclopedia of paleoherpetology), part 4. friedrich pfeil, munich,1–275 p. sebe, k., selmeczi, i., szuromi-korecz, a., hably, l., kovács, á. & benkó, zs. (2019): miocene syn-rift lacustrine sediments in the mecsek mts. (sw hungary).‒ swiss journal of geosciences, 112, 83–100. doi: 10.1007/s00015018-0336-1 selmeczi, i., kókay, j., hámor, g., vető, i. (2023): hidasi formáció [hidas fm.].‒ in: babinszki, e., piros, o., csillag, g., fodor, l., gyalog, l., kercsmár, zs., less, gy., lukács, r., sebe, k., selmeczi, i., szepesi, j. & sztanó, o. (eds.): magyarország litosztratigráfiai egységeinek leírása ii. kainozoos képződmények [cenozoic lithostratigraphic units of hungary ii. cenozoic formations – in hungarian]. supervising authority of regulated activities, budapest, 92–93. sen, s. (1997): magnetostratigraphic calibration of the european neogene mammal chronology.− palaeogeography, palaeoclimatology, palaeoecology, 133/4, 181– 204. doi: 10.1016/s0031-0182(97)00079-5 steininger, f. (1999): chronostratigraphy, geochronology and biochronology of the miocene „european land mammal mega-zones (elmmz) and miocene „mammal-zones (mn-zones)”.− in: rössner, g. & heissig, k. (eds.): the miocene land mammals of europe. verlag dr. friedrich pfeil, münchen., 9–24. szabó, m., kocsis, l., tóth, e., szabó, p., németh, t. & sebe, k. (2022): chondrichthyan (holocephali, squalomorphii and batomorphii) remains from the badenian of southern hungary (tekeres, mecsek mountains): the first deepwater cartilaginous fishes from the middle miocene of the central paratethys.‒ papers in palaeontology, e1471, 50 p. doi: 10.1002/spp2.1471 vadász, e. (1935): a mecsekhegység [the mecsek mountains – in hungarian].‒ hungarian royal geological institute, budapest, 180 p. van dam, j. & weltje, g. (1999): reconstruction of the late miocene climate of spain using rodent palaeocommunity successions: an application of end-member modelling.‒ palaeogeography, palaeoclimatology, palaeoecology, 151/4, 267–305. doi: 10.1016/s0031-0182 van der meulen, a. & de bruijn, h. (1982): the mammals from the lower miocene of aliveri (island of evia, greece). part 2. the gliridae.‒ proceedings of the koninkljke nederlandse akademie van wetenschappen, ser b., 85/4, 485–524. venczel, m. (2004): middle miocene anurans from the carpathian basin.‒ palaeontographica abteilung a 271, 151–174. doi: 10.1127/pala/271/2004/151 venczel, m. & hír, j. (2013): amphibians and squamates from the miocene of felsőtárkány basin, n-hungary.‒ palaeontographica abteilung a 300, 117–158. doi: 10.1127/pala/300/2013/117 venczel, m. & hír, j. (2015): lissamphibians and squamate reptiles from the early middle miocene of litke, northern hungary.‒ geobios, 48, 491–504. doi: 10.1016/j. geobios.2015.09.001 weerd van de, a. & daams, r. (1978): quantitative composition of rodent faunas in the spanish neogene and paleoecological implications.‒ in: proceedings of the koninklijke nederlandse akademie van wetenschappen, ser b, 81/4, 448-473. zachos, j., pagani, m., sloan, s., thomas, e., billups, k. (2001): trends, rhythms, and aberrations in global climate 65 ma to present.‒ science, 292, 686–693. doi: 10.1126/science.1059412 ziegler, r. & fahlbusch, v. (1986): kleinsäuger-faunen aus der basalen oberen süsswasser-molasse niederbayerns.− zitteliana, 14, 3–80. 2021 | 74/3 | 209–223 | 7 figs. | 1 tab. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the cretaceous deposits are widely distributed in the algerian saharan atlas. in the last few years, several sedimentological, bio-lithostratigraphic and palaeontological studies were focused on the mid-cretaceous strata of the western (ksour mounts) and central saharan atlas (djebel amour mounts) (mebarki et al., 2016; benyoucef et al., 2017; ferré et al., 2017; mennad et al., 2020; salhi et al., 2020; özer & benyoucef, 2021). in the ouled nail mounts (eastern part of the saharan atlas), the corresponding deposits are represented by a succession made of marly-limestone/dolostone alternations which display a rich macrofauna (bivalves, gastropods, ammonites), as well as trace fossils. the best exposures of this interval crop out in the djebel azzeddine, djebel amrane and djebel tsegna, and were first extensively explored by brossard (1866), péron (1883) and ritter (1902). the studied interval has been mapped and investigated since the late mid 20th century (emberger, 1960; guiraud, 1973; herkat, 1999). unfortunately, with the exception of the previously cited works, no comprehensive revision of the upper albian-lower cenomanian succession has been carried out in recent years. the late albian (vraconnian) – lower cenomanian interval is thereby considered as an important eustatic event, corresponding to the global and greatest mid-cretaceous transgression (hancock & kauffman, 1979; amédro, 2008). this paper aims to provide the first sedimentological and ichnological study of the upper-albian transgressive marine deposits exposed in djebel azzeddine (ouled nail mounts). our contribution provides the first ammonite-bearing level, ichnotaxa inventory, detailed facies analysis and new dinosaur footprint record that facilitates identification of the depositional environment and the palaeobiogeography in the saharan atlas during the midcretaceous. sedimentology and ichnology of the mid-cretaceous succession of the ouled nail mounts (eastern saharan atlas, algeria) mohammed nadir naimi and amine cherif université kasdi merbah, laboratoire de géologie du sahara, ghardaïa road, ouargla, 30000, algeria; (naimi.mohamed_nadir@univ-ouargla.dz (mohammed nadir naimi), acherif11@gmail.com (amine cherif)) doi: 10.4154/gc.2021.15 abstract shallow marine deposits characterize the upper albian – lower cenomanian deposits of northern algeria. in djebel azzeddine (ouled nail mounts), the corresponding sediments have been subdivided into three distinctive units a to c. the first discovered ammonite fauna from the bou saada area allowed the attribution of a part of the mid-cretaceous post-continental intercalaire deposits to the upper albian. the ammonite-bearing level indicates a maximum flooding surface and could be correlated with similar levels from northern algeria. the studied succession is characterized by a low ichnodiversity containing eight ichnotaxa with abundant thalassinoides, common skolithos, and rare gyrolithes, oichnus, planolites and cf. tisoa. this ichnoassemblage is dominated by domichnion, fodinichnion and praedichnion trace fossils, and is attributed to the skolithos and glossifungites ichnofacies. these traces are produced mainly by decapod crustaceans, polychaetes and naticid gastropods. the sedimentological and ichnological data suggest shoreface to backshore environments with mixed tide/storm energy, and long subaerial exposures indicated by lofer cyclothems in the lowermost part and dinosaur footprints in the upper part of the section. 2. geological setting the algerian atlasic system consists of the saharan atlas to the west, and the aures, nementcha, negrine and tebessa mountains to the east (e.g., djebbar, 2000). their equivalents are the high and middle atlas in morocco, and the tunisian atlas in tunisia, forming, together with the tell-rif system to the north, the atlas mountains belts sensu lato of northwestern africa (halamski & cherif, 2017), considered as part of the west mediterranean alpine system (fig. 1a). the ouled nail mounts represent the eastern part of the saharan atlas (fig. 1b), which corresponds to an intracratonic autochthonous chain located in northern algeria, belonging to the atlasic system (djebbar, 2000; naimi & cherif, 2021a; naimi et al., 2021a). the algerian saharan atlas extends swne over about 650 km in length and 90 to 140 km wide between the moroccan high-atlas and the zibane mountains (or biskra promontory) (guiraud, 1973). this chain was developed in a subsiding intra-plate asymmetric basin, in existence since the triassic, located between two stable domains, the oran meseta (high plateaus) in the north, and the saharan platform in the south, from which it is respectively isolated, by the south mesetan and the south atlasic faults (kazi-tani, 1986). the stratigraphic series (fig. 1c) of the study area (the northeastern part of the ouled nail mounts) begins with triassic strata cropping out in diapirs (kerdada and ain ograb), represented by purplish clays, gypsum, dolostones and doleritic ophites. the triassic rocks are overlain by a 6000 m-thick cretaceous (valanginian to maastrichtian) succession. the cenozoic (paleogene to quaternary) continental deposits unconformably overlie the mesozoic sediments (emberger, 1960). the mid-cretaceous sedimentary succession cropping out in the investigated area is characterized by lower albian continental sandstones of the continental intercalaire, rich in the rearticle history: manuscript received december 15, 2020 revised manuscript accepted may 31, 2021 available online october 15, 2021 keywords: trace fossils, transgression, albian – cenomanian, ouled nail mounts, algeria g eo lo gi a c ro at ic a geologia croatica 74/3210 mains of vegetation (emberger, 1960), overlain by shallow marine carbonate platform deposits. the lower part (300–400 m) of this sequence is dated as upper albian, consisting of marlydolostone alternations rich in fragments of oyster shells. the palae ontological content of these facies suggests a very shallow marine environment under rough-water conditions (naimi et al., 2021b). the lower part of the overlying 460–735 m-thick cenomanian strata is characterized by shallow-water marlstone-limestones. they are similar to the underlying upper albian deposits, figure 1. location map of the study area. (a) location of central algeria in the western mediterranean; (b) the main structural domains of central algeria; (c) simplified geological map of the bou saada area (modified after the geological map of bou saada 1/200.000); (d) late albian global palaeogeography and location of the ouled nail basin (map after scotese, 2013). g eologia c roatica naimi and cherif: sedimentology and ichnology of the mid-cretaceous succession of the ouled nail mounts (eastern saharan atlas, algeria) 211 figure 2. the main lithostratigraphic characteristics of the upper albian – lower cenomanian of djebel azzeddine. (a) lithostratigraphic column of the djebel azzeddine section; (b) field photography of the studied succession: 1, dolomitic limestones of the lowermost part of the section; 2, thalassinoides-rich beds; 3, algal limestones of the uppermost part of unit a (black arrow shows the chert level); 4, micritic limestones of unit b; 5, gastropod-rich limestones; 6, the lowermost part of unit c (white arrow indicate ammonites-bearing limestones; black arrow indicate dinosaur tracks-bearing dolostones); 7, dinosaur tracks-bearing surface; 8, marls-shelly limestones alternation from the uppermost part of the section. g eo lo gi a c ro at ic a geologia croatica 74/3212 rich in oysters and echinoderms, and overlain by lagoonal marlstone-dolostone alternations and thick gypsum beds with subordinate limestone interlayers rich in foraminifera (emberger, 1960). the uppermost part of the cenomanian beds consists of massive mudstones, nodular and bioclastic limestones and black shales (grosheny et al., 2008). 3. material and methods two field expeditions (december 2019 and march 2020) were conducted. during these missions the mid-cretaceous succession cropping out in djebel azzeddine near the city of bou saada was sampled and described bed-by-bed for lithological changes, colour, composition, geometry, sedimentary structures and palaeontological content. the fossils (bivalves, gastropods, ammonites and brachiopods) as well as trace fossils were photographed in situ, collected and stored in the géologie du sahara laboratory (kasdi merbah university) to be identified and investigated for their palaeoenvironmental interest. a new dinosaur tracksite was discovered in the studied succession. however, further studies on these footprints are required. 4. lithostratigraphic framework and palaeoenvironment the upper albian – lower cenomanian deposits of djebel azzeddine were framed as vraconnian – cenomanian, corresponding to a megasequence, divided into two fourth-order sequences (herkat, 1999). in the present work, the studied interval has been subdivided into three informal units (fig. 2). 4.1. unit a: marlstone-algal bioturbated limestones unit (upper albian) this 52 m-thick unit constitutes the base of the marine mid-cretaceous deposits outcropping near the city of bou saada. its lower limit has been hidden due to recent urbanization. emberger (1960) indicates that djebel azzeddine marine carbonates overlie albian sandstones of the continental intercalaire. the dominant stacking pattern of this unit is represented by an obvious rhythmicity expressed by discrete bed packages (0.6 – 6 m thick) of limestones and dolomitic limestones intercalated with greenish to grayish soft, occasionally foliated, fossiliferous marlstones (0.6 – 3 m) (fig. 2). the limestones are hard, highly burrowed with large thalassinoides isp. (fig. 7a) and organized in shallowing upwards wackestone to packstone. they are massive, sub-nodular (fig. 3a), rarely laminated, yellow, light to dark brown in colour when weathered, white to light gray in cross-section and mostly with sharp erosive bases. the fossil components are dominated by oysters, gastropods and echinoids. these dolomitic limestones show a red loferitic breccia, mud cracks, parallel laminations, micro-hcs (hummocky-cross stratifications), stromatolitic laminae, silex layers, paleosol, teepee structures and shrinkage pores (fig. 3b, d and e). the upper contact of this unit figure 3. field photographs of unit a. (a) pseudo-nodular limestones; (b) intertidal to supratidal limestones with algal laminae, paleosol, shrinkage pores (black arrows), and loferitic breccia (white arrow); (c) subtidal limestones with in-situ slumped breccia; (d) stromatolitic limestone; (e) dolomitic limestone showing algal laminae including chert nodules; (f) top surface of dolomitic limestone showing hardground with abundant acteonella delgadoi. g eologia c roatica naimi and cherif: sedimentology and ichnology of the mid-cretaceous succession of the ouled nail mounts (eastern saharan atlas, algeria) 213 corresponds to a hardground with oxidized dolo-mudstones characterized by condensed gastropod levels dominated by the species actnonella delgadoi, as well as vertical borings (fig. 3f). 4.2. unit b: lower marlstone-shelly limestone unit (upper albian) this 22.5 m-thick unit comprises white and green marls (0.2 – 2.5 m) alternating with grayish to yellowish massive, shelly and sandy limestones. the limestone beds are 0.05 to 2.5 m thick, broadly pseudo-nodular to nodular, bioturbated, channelized, white to dark gray weathering coloured, gray to yellowish in cross-section, showing noteworthy densely packed thin bioclasts of benthic fauna, organized in packstone to grainstone textures (fig. 4a). the middle part of this unit exhibits many subordinate shell beds (0.2 – 2.5 m thick), thinning upwards, amalgamated and wave rippled, showing a rapid transition into an overlying marly lithofacies, namely: cucullaea-rich limestones corresponding to bioturbated limestone, composed of monotaxic bivalves (cucullaea sp.) (fig. 4b), and polytaxic gastropod-rich limestones with fragmented and randomly oriented shells (fig. 4c). a scarce brachiopod fauna is also present. internally, the limestone beds of this unit contain small scale hummocky-cross stratifications, lenticular, flaser to wavy bedding, internal mud drapes, tidal rhythmites, unidirectional, linguoid, wavy ripple marks and mega ripples (fig. 4d-e). the ichnotaxa of this unit are represented by gyrolithes isp. (fig. 6a), oichnus isp. (fig. 6b) and cf. tisoa siphonalis (fig. 7e). figure 4. field photographs of unit b. (a) micritic limestone bed; (b) cucullaea-rich limestones; (c) gastropod-rich limestones, with sharp erosive base and ripplemark in top surface; (d) small-scale hummocky-cross stratification in fine limestone bed at the top of the unit, with light micritic laminae and dark sandy-micritic laminae; (e) tidal rhythmites from the top of the unit; (f) limestone bed with robust bioclasts of oysters and wavy rippled upper surface; (g-h) large size mortoniceracidae of the ammonites-bearing bed. g eo lo gi a c ro at ic a geologia croatica 74/3214 the uppermost part of this unit is representedby a concentration of large-sized ammonites mortoniceras sp. and pervin­ quieria sp., arranged in single post-mortem disposition (fig. 4g-h), and small fragments of engonoceras sp. which co-occur with bivalves and gastropods. 4.3. unit c: upper marlstone-shelly limestone unit (upper albian – lower cenomanian) the lower part of this 18 m-thick unit is composed of an alternation of white marls (2 – 3 m) and whitish massive limestones with sporadic, thin, bivalve shell beds of cucullaea sp. these limestone beds are hard, display yellow-red sandy inclined burrows as planolites isp. (fig. 6c), hummocky-cross stratifications (hcs), swaley-cross stratifications (scs) and parallel and cross laminations (fig. 5a-b). the 2 – 3 m-thick dolomite in the middle part of this unit is characterized by dinosaur footprints (figs. 8 and 9) associated with vertical burrows attributed to skolithos (fig. 6d), as well as a rich assemblage of worn and recrystallized molds of bivalves and gastropods. the uppermost part of the studied succession consists of regular alternations of light green to white soft marls (fig. 5e-f) and mollusk rich limestones, composed of abundant disarticulated and fragmented (fig. 5c) or whole mollusk shells including bivalves and gastropods (fig. 5d). 4.4. facies analysis on the basis of sedimentological and palaeontological characteristics such as lithology, sedimentary structures, fossils and/or trace fossils, bed thickness and taphonomy of shell beds, fifteen distinctive sedimentary facies types (ft1 to ft15) have been identified, described, interpreted and presented in table 1 and figures 3–5. 4.5. age of the succession despite the extension of the mid-cretaceous succession of the ouled nail mounts, no detailed bioand lithostratigraphic investigations have been previously carried out on these deposits. emberger (1960), based only on lithological criteria, such as the occurrence of rich oyster shell fragment-limestones, assigned a latest albian (vraconnian) and early cenomanian age to the midcretaceous marine sediments of the djebel azzeddine section. furthermore, herkat (1999) assigned the same deposits to a whole vraconnian-cenomanian mega-sequence encompassing three successive sequences. our new findings indicate a late albian-lower cenomanian age for the mid-cretaceous deposits of the ouled nail mounts. no biostratigraphic fossils have been recorded in the lowermost part of the analyzed succession. the last bed of the first unit contains a condensed gastropod shell-bearing level of acteonella figure 5. field photographs of unit c. (a) limestone bed with low-angle cross lamination; (b) limestone bed showing hummocky cross-stratification (hcs) and swaley cross-stratification (scs); (c) oyster-rich bioclastic limestone (black arrows indicate echinoid spines); (d) limestone bed rich in gastropod and pectinid shells; (e) greenish marls interlayered with limestone beds; (f) uppermost part of the succession showing rhythmic whitish marls-dolomitic limestones alternations. g eologia c roatica naimi and cherif: sedimentology and ichnology of the mid-cretaceous succession of the ouled nail mounts (eastern saharan atlas, algeria) 215 ta bl e 1. d es cr ip tio n an d se di m en to lo gi ca l a tt rib ut es o f l ith of ac ie s i de nt ifi ed in th e up pe r a lb ia n – lo w er c en om an ia n de po si ts o f d je be l a zz ed di ne (o ul ed n ai l m ou nt s, a lg er ia ). fa ci es ty pe (f t) d es cr ip tio n an d ra ng e in te rp re ta tio n an d en vi ro nm en ta l s ig ni fic an ce ft 1. su bno du la r d ol om iti c lim es to ne s m ar ls to ne -a lg al b io tu rb at ed li m es to ne s u ni t th ey c on si st o f y el lo w is h to b ro w ni sh , h ar d, m as si ve o r s ca rc el y la m in at ed , p oo rly fo ss ili fe ro us , 0 .6 to 3 m -t hi ck , fi ne -g ra in ed d ol om iti c lim es to ne b ed s. th e m ai n fa un al c om po ne nt s a re g as tr op od s, ra re ec hi no id s, an d hi gh ly fr ag m en te d an d di sa rt ic ul at ed o ys te rs , w hi ch a re o rie nt ed h or iz on ta lly to th e be dd in g. t he se di m en ta ry st ru ct ur es a re re pr es en te d by h or iz on ta l l am in at io ns a nd m ic ro hu m m oc ky -c ro ss st ra tifi ca tio ns . t he b ed s a re in te ns iv el y bi ot ur ba te d. h ow ev er , t he lo ca lly su bno du la r t o no du la r a sp ec t ( fi g. 3 a) is d ue to a bu nd an t l ar ge t ha la ss in oi de s ( t. is p. a nd t . s ue vi cu s) (f ig . 7 a a nd d ). th e bi ol og ic al c om po ne nt a nd ic hn ol og ic al a ss oc ia tio n of th is fa ci es su pp or ts m id dl e sh or ef ac e en vi ro nm en t ( e. g. , h o w a rd & f re y, 1 98 4) , w ith w el l-o xy ge na te d w at er a bo ve th e se a flo or (n a im i e t a l., 2 02 0) . t he p re se nc e of hu m m oc ky -c ro ss st ra tifi ca tio ns w ith o rie nt ed , f ra gm en te d an d di sa rt ic ul at ed b en th ic fa un a su ch a s o ys te rs a nd ec hi no id s p oi nt s t o hi gh e ne rg y de po si ts re la te d to p er io di c st or m e ve nt s. ft 2. lo fe rit es m ar ls to ne -a lg al b io tu rb at ed li m es to ne s u ni t th e lo fe rit es a re th e m os t w id es pr ea d fa ci es in th e an al yz ed su cc es si on . t he y co ns is t o f l ig ht y el lo w to da rk b ro w n, 0 .8 to 6 m -t hi ck d ol om iti ze d be ds , m ad e by c om pl et e lo fe r c yc le s, re pr es en te d by : ( i) do lo m iti c lim es to ne s, si m ila r t o th at o f t he f t1 , w ith re w or ke d an d tr an sp or te d bi oc la st s a nd sh el l de br is , s ho w in g in -s itu sl um pe d br ec ci at io n (f ig . 3 c) ; ( ii) h or iz on ta l, irr eg ul ar ly u nd ul at in g an d la te ra lly c on tin uo us , s tr om at ol iti c cr yp to al ga l l am in ae (f ig . 3 d ); an d (ii i) re d so il w ith re d lo fe rit ic br ec ci a, te pe e st ru ct ur es , s hr in ka ge p or es c on ta in in g in te rn al se di m en t a nd m ill im et er t o ce nt im et er si ze d gy ps um c ry st al s a nd m ud c ra ck s ( fi g. 3 b) . th e gy ps um c ry st al s g re w d is pl ac iv el y as le nt ic ul ar c ry st al s w ith in th e al ga l m at s. fu rt he rm or e, th e la st b ed b el on gi ng to th is fa ci es sh ow s d is co nt in uo us b la ck is h ch er t b an d w hi ch d is pl ay s a n od ul ar an d ca ul ifl ow er -s ha pe d pa tt er n an d co -o cc ur s w ith st ro m at ol iti c la m in ae (f ig . 3 e) . th es e cy cl es m ay b e co rr el at ed w ith l of er -t yp e fa ci es o f t he t ria ss ic o f t he a us tr ia n a lp s ( fi sc h er , 1 96 4) . t he y in di ca te a re gr es si ve sh al lo w in gup w ar d tr en d, a nd m ay re pr es en t i de al e le m en ta ry c yc lo th em s ( se ns u d ’a rg en io , 19 74 a nd s tr a ss er , 1 99 1) . h ow ev er , t he y ar e m et er -s ca le , c or re sp on di ng to th re e su cc es si ve m em be rs : ( i) m em be r c: su bt id al d ol os to ne b ed s r ep re se nt ed b y do lo m iti c lim es to ne s w hi ch y ie ld ed b en th ic fo ra m in ife ra (m ili ol id s) a nd en cr us te d al ga e (e m be rg er , 1 96 0) ;(i i) m em be r b : s tr om at ol iti c do lo st on es a ss oc ia te d w ith ti da l-fl at fe at ur es (te ep ee s, sh rin ka ge p or es , g yp su m c ry st al s a nd m ud c ra ck s) , a nd d em on st ra te a re st ric te d in te rt id al z on e (s h in n , 19 83 ); an d (ii i) m em be r a : r ed p al eo so ls a nd lo fe rit ic b re cc ia (s up ra tid al so il co ng lo m er at es ),c on si de re d as d ia gn os tic of a su ba er ia l e xp os ur e re la te d to p ed og en es is p ro ce ss in n ea rb y em er ge d ar ea s, an d th ey a re c om pa tib le s w ith th e m em be r a o f t he l of er c yc lo th em . th e in -s itu b re cc ia tio n an d sl um p br ec ci a ar e in te rp re te d as lo ca l c ol la ps es o f t he c ar bo na te p la tfo rm re la te d to ac tiv e te ct on ic s ( ia n n ac e et a l., 2 01 4) . u nf or tu na te ly , n o sy nse di m en ta ry fa ul ts o r o th er p al ae ot ec to ni c fe at ur es w er e de te ct ed . h ow ev er , h er ka t & g u ir au d (2 00 6) e vi de nc ed a te ct on ic in st ab ili ty d ur in g th e la te a lb ia n in o th er lo ca lit ie s f ro m o ul ed n ai l b as in , t o th e so ut h of o ur st ud y ar ea . th e lo fe rit es (f t2 ) s ug ge st a su pr at id al (b ac ks ho re ) t o a su bt id al (s ho re fa ce ) d ep os iti on al e nv iro nm en t, w ith a pr ol on ge d ex po su re o n th e tid al fl at s. ft 3. th al as sin oi de sric h be ds m ar ls to ne -a lg al b io tu rb at ed li m es to ne s u ni t th is fa ci es c or re sp on ds to y el lo w is h sa nd y no du la r s an dy li m es to ne s, 0. 25 to 1 .2 m th ic k, ri ch in th al as sin oi de s p ar ad ox ic us . t he n od ul ar a pp ea ra nc e of th es e be ds is d ue to th e hi gh d en si ty o f t he se tr ac e fo ss ils (f ig . 7 c) . t. p ar ad ox ic us su gg es ts a lo w e ne rg y en vi ro nm en t ( m á n g a n o & b u at o is , 1 99 1) . f ur th er m or e, a si m ila r f ac ie s f ro m th e lo w er c re ta ce ou s o f a rg en tin a ha s b ee n in te rp re te d as a d is co nt in ui ty su rf ac e, re pr es en tin g a ch an ge o f l oc al en vi ro nm en ta l c on di tio ns a nd a d ec re as e of se di m en ta tio n ra te (m á n g a n o & b u at o is , 1 99 1) . ft 4. ac te on el la -r ic h be d m ar ls to ne -a lg al b io tu rb at ed li m es to ne s u ni t th is fa ci es c or re sp on ds to re dd is h m as si ve d ol om iti ze d lim es to ne s, 2 m -t hi ck o n av er ag e, in cl ud in g a m on ot ax ic c on de ns at io n of a ct eo ne lla d el ga do i c ho ffa t, 19 01 a nd v er tic al b or in gs fi lle d w ith ye llo w is h sa nd y m at er ia l. t he se g as tr op od s a re ra nd om ly o rie nt ed , m od er at el y so rt ed , d en se ly pa ck ed a re re la tiv el y fra gm en te d (f ig . 3 f) . a ls o, th ey a re n ei th er b or ed n or e nc ru st ed . ac te on el la o cc ur s i n sh al lo w m ar in e or fu ll m ar in e la go on s ( ko w a lk e & ba n d el , 1 99 6) , w ith a n in fa un al w ay o f l ife (s o h l & ko ll m a n n , 1 98 5) . f ur th er m or e, th e ta ph on om ic c ha ra ct er is tic s o f a . d el ga do i s he lls in di ca te a n in si tu pr es er va tio n su cc ee di ng sh or t p os tm or te m p er io d. ft 5. m ic rit ic li m es to ne s lo w er m ar ls to ne -s he lly li m es to ne s u ni t th is fa ci es c on si st s o f w hi tis h to g re en is h fin egr ai ne d m ic rit ic m as si ve , s ub -n od ul ar a nd ta bu la r lim es to ne s ( fi g. 4 a) , 3 – 4 m -t hi ck , s ho w in g an in te rm itt en t h or iz on ta l l am in at io n, c on ta in in g bi va lv e fa un a, h ig hl y bo re d by c irc ul ar to su bc irc ul ar b or in gs a ss ig ne d to o ic hn us is p. (f ig . 6 b) . i n th in se ct io ns , t he m ic rit ic li m es to ne s f ac ie s s ho w s b en th ic a nd p la nk to ni c fo ra m in ife ra e m be dd ed in a m ud st on ew ac ke st on e te xt ur e. th is fa ci es w as d ep os ite d in a n op en m ar in e se tt in g, u nd er lo w e ne rg y co nd iti on s, be lo w st or m w av e ba se (b en yo u ce f et a l., 2 01 7) . o ic hn us is c on si de re d as p re da to ry g as tr op od b or in gs , w hi ch o cc ur o n br ac hi op od , ec hi no id , a nd m ol lu sc an sh el ls . i n op en m ar in e se tt in g, it h as b ee n re co rd ed fr om o ffs ho re se di m en ts (g ru n e t a l., 20 17 ). ft 6. bi oc la st ic p se ud ono du la r l im es to ne s lo w er m ar ls to ne -s he lly li m es to ne s u ni t ft 6 co rr es po nd s t o ps eu do -n od ul ar to n od ul ar , b io cl as tic , c ha nn el iz ed , g ra yi sh to y el lo w is h, 0 .0 5 – 2. 5 m th ic k lim es to ne s. th e bi oc la st ic c on te nt c on si st s g en er al ly o f f ra gm en ts o f m on os pe ci fic o ys te r sh el ls fr ag m en ts ra nd om ly o rie nt ed , m od er at el y to h ig hl y fra gm en te d, a br ad ed a nd re la tiv el y po or ly so rt ed , e m be dd ed in a p ac ks to ne to g ra in st on e ce m en t. ec hi no id sp in es a re a ls o pr es en t. so m e ra re tr ac e fo ss ils su ch a s c f. ti so a sip ho na lis h as b ee n ob se rv ed in th is li th of ac ie s ( fi g. 7 e) . in v er y sh al lo w m ar in e se tt in g, t iso a su pp or ts h ig h en er gy c on di tio ns (b o ck el ie , 1 99 1; k n au st , 2 01 9) , w hi ch c an b e su gg es te d in th e st ud ie d su cc es si on b y th e fra gm en te d an d di so rie nt ed o ys te r w ith in a li m es to ne m at rix . t he pr es en ce o f b en th ic b io cl as ts is re la te d to st or m e ve nt s, in a sh or ef ac e de po si tio na l e nv iro nm en t. ft 7. cu cu lla ea -r ic h lim es to ne s lo w er m ar ls to ne -s he lly li m es to ne s u ni t a nd u pp er m ar ls to ne -s he lly li m es to ne s u ni t th e sh el l b ed s a re m ad e of a m on ot ax ic c on ce nt ra tio n of th e bi va lv es c uc ul la ea sp . t he se li m es to ne be ds a re w hi tis h, la te ra lly c on tin uo us , 0 .2 – 0 .4 m , m at rix su pp or te d, sh ow in g in te rn al e ro si on -s ed im en ta tio n su rf ac es . f t7 is v er y ric h in sh el ls w hi ch a re lo os el y fra gm en te d an d ab ra de d or m os tly co m pl et e an d w el l-p re se rv ed , o rie nt ed p ar al le l t o be dd in g (f ig . 4 b) . t he re by , t he y ar e ne ith er en cr us te d no r b io er od ed . cu cu lla ea b iv al ve s a re w el l k no w n in th e m id a nd u pp er c re ta ce ou s d ep os its fr om se ve ra l s ou th te th ya n re gi on s a s w el l a s a lg er ia , e gy pt , j or da n, m or oc co a nd t un is ia , o cc ur rin g in sh al lo w m ar in e lim es to ne s ( e. g. , n ag m & b o u a le m , 20 19 ). th e st ud ie d sp ec im en s a re c on si de re d to c on st itu te th e fir st re co rd fr om a lg er ia . t he lo w d eg re e of fra gm en ta tio n, th e la ke o f b io er os io n an d en cr us ta tio n in di ca te v er y lim ite d tr an sp or t. cu cu lla ea -r ic h lim es to ne s h as be en c on si de re d as c ha nn el la gs o f l at er al ly m ig ra tin g su bt id al c ha nn el s, de ve lo pi ng a t e st ua rin e to sh al lo w m ar in e off th e m ou th o f a w av e an d tid e in flu en ce d es tu ar y (m a re n ss i e t a l., 1 99 8) d ur in g a sl ow tr an sg re ss iv e ev en t. g eo lo gi a c ro at ic a geologia croatica 74/3216 fa ci es ty pe (f t) d es cr ip tio n an d ra ng e in te rp re ta tio n an d en vi ro nm en ta l s ig ni fic an ce ft 8. g as tr op od -r ic h lim es to ne s lo w er m ar ls to ne -s he lly li m es to ne s u ni t th is fa ci es c or re sp on ds to g ra yi sh a m al ga m at ed li m es to ne b ed s, 0. 2 – 0. 5 m -t hi ck , s ho w in g sh ar p er os iv e ba se s, co m po se d m ai nl y of a bu nd an t p ol yt ax ic g as tr op od s. th ey a re d en se ly p ac ke d, ra nd om ly o rie nt ed , h ig hl y fra gm en te d an d fla tt en ed b y co m pa ct io n, a nd e xh ib it si gn s o f a br as io n (f ig . 4 c) . t he to p of th e be ds sh ow w av e rip pl es a nd sc ar ce tr ac e fo ss ils . th e ch ar ac te ris tic s o f t hi s f ac ie s a s w el l a s t he sh ar p er os iv e ba se , t he h ig h de gr ee o f f ra gm en ta tio n an d de ns e pa ck in g of b io cl as ts in di ca te st or m -in du ce d cu rr en ts tr an sp or tin g ga st ro po d. t he se di m en to lo gi ca l a nd ta ph on om ic da ta su gg es t w av e to st or m d om in at ed p la tfo rm , a bo ve th e fa irw ea th er w av e ba se (s ho re fa ce ). ft 9. la m in at ed li m es to ne s lo w er m ar ls to ne -s he lly li m es to ne s u ni t th e la m in at ed li m es to ne s a re w hi tis h to y el lo w is h be ds , 0 .1 – 0 .6 m -t hi ck , c on ta in in g sm al l s ca le h cs (h um m oc ky -c ro ss st ra tifi ca tio ns ), le nt ic ul ar , fl as er to w av y be dd in g, in te rn al m ud d ra pe s, an d ve rt ic al ly st ac ke d bu nd le s o f a lte rn at in g sa nd st on e/ m ud st on e pa ra lle l l am in at io ns (t id al rh yt hm ite s) (f ig . 4 d -e ). th e to p su rf ac es o f t he b ed s a re c om m on ly c ha ra ct er iz ed b y un id ire ct io na l, lin gu oi d an d w av y rip pl e m ar ks a nd m eg a rip pl es . t hi s f ac ie s c an a ls o co nt ai n ab un da nt d is ar tic ul at ed a nd fra ct ur ed o r w ho le m ol lu sk sh el ls (t hi ck -s he lle d oy st er s) (f ig . 4 f) , a nd sp ira l b ur ro w s p er pe nd ic ul ar to th e be dd in g, a ss ig ne d to th e ic hn og en us g yr ol ith es is p. (f ig . 6 a) . th e re co rd ed se di m en ta ry fe at ur es o f t hi s f ac ie s s ug ge st a ti da l fl at e nv iro nm en t, ch ar ac te riz ed b y an a lte rn at io n of lo w a nd h ig h en er gy p er io di c tid al fl at d ep os its (c h er if e t a l., 2 01 8) . t he p re se nc e of th e tr ac e fo ss il g yr ol ith es in di ca te s a sh al lo w m ar in e en vi ro nm en t ( in te rt id al z on e) , w ith st iff a nd /o r fi rm su bs tr at es (n et to e t a l., 2 00 7) . t he in te ns e fra gm en te d bi oc la st s a nd h um m oc ky -c ro ss st ra tifi ca tio ns p ro vi de e vi de nc e of p er io di c st or m e ve nt s a nd de po si tio n in a w av e/ tid edo m in at ed z on e (lo w er fo re sh or e to u pp er sh or ef ac e en vi ro nm en t). ft 10 . a m m on ite sbe ar in g lim es to ne s lo w er m ar ls to ne -s he lly li m es to ne s u ni t ft 10 c on si st s o f c on de ns ed a m m on ite b ed , f or m ed b y fin egr ai ne d ye llo w is h to g ra yi sh sa nd y an d gl au co ni tic li m es to ne s, 0. 8 cm th ic k, ri ch in m or to ni ce ra tin ae a nd e ng on oc er at id ae , a rr an ge d in si ng le po st -m or te m d is po si tio n, a ss oc ia te d w ith a bu nd an t b iv al ve s c uc ul la ea sp ., oy st er s, ra re in oc er am id s an d ga st ro po ds . i t c on st itu te s t he o nl y fa ci es c on ta in in g am m on ite fa un a al on g th e se ct io n. t he se am m on ite s b el on g to m or to ni ce ra s s p. , p er vi nq ui er ia sp . a nd e ng on oc er as sp . pe rv in qu ie ria sp . s pe ci m en s a re a bu nd an t o n th e to p of th e be d, a nd th ey a re c ha ra ct er iz ed b y th ei r la rg e di am et er o ft en a bo ut 2 5 cm (f ig . 4 g -h ). h ow ev er , e ng on oc er as sp . s am pl es a re fr ag m en te d an d sh ow w el l-p re se rv ed su tu re s. en go no ce ra tid ae o cc ur in sh al lo w m ar in e en vi ro nm en ts , i n pa rt ic ul ar in g la uc on iti c se di m en ts , s om e of th em pr ef er rin g tid al a nd la go on al w at er s ( bu tj o r, 2 01 0) . t he c ooc cu rr en ce o f i no ce ra m id s w ith g as tr op od s i nd ic at es sh al lo w m ar in e se tt in gs , w ith w ar m w at er s a nd w el l o xy ge na te d en vi ro nm en t d ur in g tr an sg re ss iv e ph as es (b o u a le m , 2 01 8) . m or to ni ce ra tin ae su gg es t a n op en m ar in e se tt in g, a nd th ei r p re se nc e in sh al lo w m ar in e de po si ts po in ts to p os tm or te m d rif tin g. t he n on fr ag m en ta tio n of m or to ni ce ra tid sh el ls c ou ld b e re la te d to c al m -w at er co nd iti on s a nd ra pi d bu ria l b y th e de ca nt at io n of th e fin e pa rt ic le s i n su sp en si on . a ls o, th e pr es en ce o f g la uc on ite in su ch sh al lo w e nv iro nm en t i s r el at ed to u pw el lin g ph en om en a (b ra n d a n o e t a l., 2 02 0) . c on se qu en tly , t he tr an sp or t of m or to ni ce ra tid s c ou ld b e th e re su lt of th es e pr oc es se s. ft 11 . st ru ct ur el es s l im es to ne s u pp er m ar ls to ne -s he lly li m es to ne s u ni t th is fa ci es is c om po se d of h ar d lim es to ne b ed s, w hi tis h w ea th er in g co lo rgr ay is h in fr es h, 0 .2 – 0 .3 m th ic k, d is pl ay in g st ro ng c on cr et io na ry v er tic al b ur ro w s fi lle d w ith y el lo w -r ed c oa rs er -g ra in ed sa nd y m at er ia l, as so ci at ed w ith p la no lit es is p. (f ig . 6 c) . t he in te rn al fa ce o f t he li m es to ne b ed s i nc lu de s h cs , sc s an d pa ra lle l a nd lo w -a ng le c ro ss la m in at io ns . th e tr ac e fo ss il pl an ol ite s c ha ra ct er iz es a ll aq ua tic e nv iro nm en ts (k n au st , 2 01 7) . t he h um m oc ky c ro ss st ra tifi ca tio ns in di ca te st or m w av e ac tio n do m in at ed p la tfo rm a nd th e pr es en ce o f l ow -a ng le c ro ss b ed di ng su gg es ts w av e sw as h zo ne (b en yo u ce f et a l., 2 01 7) , r efl ec tin g an u pp er sh or ef ac e de po si tio na l e nv iro nm en t. ft 12 . d in os au r t ra ck sbe ar in g do lo st on es u pp er m ar ls to ne -s he lly li m es to ne s u ni t th e ft 12 c or re sp on ds to h ar d br ow ni sh to re dd is h do lo st on e be ds , 2 m -t hi ck , i nc lu di ng sm al l-s iz ed tr id ac ty l d in os au r f oo tp rin ts , w hi ch c om pr is e tr ac es o f d ig its ii , i ii an d iv , p re se rv ed in c on ca ve ep ire lie f. so m e vu gs a re p re se nt o n th e tr ac kbe ar in g su rf ac e an d th ey a re m in er al iz ed w ith c al ci te . th e tr ac kbe ar in g su rf ac e co nt ai ns s ko lit ho s i sp . b ur ro w s ( fi g. 6 d ) a ss oc ia te d w ith sc ar ce t ha la ss in oi de s i sp . ( fi g. 7 b) . t he se fo ot pr in ts a re v er y po or ly p re se rv ed d ue to w ea th er in g pr oc es se s a nd th ey a re as so ci at ed w ith o ys te r a nd g as tr op od re m ai ns . th e tr ac e fo ss ils s ko lit ho s a nd t ha la ss in oi de s c ooc cu r i n ve ry sh al lo w m ar in e en vi ro nm en ts , i nfl ue nc ed b y tid es a nd st or m s ( be n yo u ce f et a l., 2 01 4) . a su ba er ia l e xp os ur e is e vi de nc ed b y th e pr es en ce o f d is so lu tio nvu gs , r ed d et rit al m at er ia l, an d ox id iz ed d ol os to ne . t he c ooc cu rr en ce o f m ar in e bi va lv e an d ga st ro po d fa un a w ith d in os au rs su gg es ts m ar gi na l-l itt or al e nv iro nm en t. th e se di m en to lo gi ca l a na ly si s t og et he r w ith p al ae on to lo gi ca l a nd ic hn ol og ic al d at a in di ca te a n in te rt id al e nv iro nm en t w ith p er io di c st or m -g en er at ed e pi so de s. ft 13 . sh el ly li m es to ne s u pp er m ar ls to ne -s he lly li m es to ne s u ni t ft 13 is re pr es en te d by b io de tr ita l a nd a m al ga m m ol lu sc an p ac ks to ne -w ac ke st on e be ds , 0 .1 5 to 0 .8 cm -t hi ck , w hi tis h, c om po se d of c om pl et e or fr ag m en ta ry b iv al ve s ( pe ct in id s a nd o ys te rs ) a nd ga st ro po ds sh el ls , r an do m ly o rie nt ed p ar al le l t o be dd in g (f ig . 5 cd ). th e se di m en ta ry st ru ct ur es a re re pr es en te d by ra re h um m oc ky ( h cs ) a nd sw al ey -c ro ss st ra tifi ca tio ns (s cs ) ( fi g. 5 a -b ). th e m ic ro fa ci es , t he d is tr ib ut io n of m ol lu sc an sh el ls a s w el l a s t he se di m en to lo gi ca l f ea tu re s i nd ic at e te m pe st ite de po si ts re fe rr ed to a lo w er sh or ef ac e en vi ro nm en t, be tw ee n fa ir w ea th er w av e an d st or m w av e ba si s. ft 14 . g re en is h m ar ls m ar ls to ne -a lg al b io tu rb at ed li m es to ne s u ni t, lo w er m ar ls to ne -s he lly li m es to ne s u ni t a nd u pp er m ar ls to ne -s he lly li m es to ne s u ni t th is fa ci es c or re sp on ds to g la uc on iti c gr ee ni sh to g ra yi sh , s of t, an d oc ca si on al ly fo lia te d, 0 .6 – 7 m -t hi ck m ar ls to ne s ( fi g. 5 e) , i nc lu di ng ri ch fo ra m in ife ra , a bu nd an t o ys te r a nd g as tr op od b io cl as ts . in th is m ar ly fa ci es , n o se di m en ta ry e ve nt s h av e be en re co rd ed , b ut th e pr es en ce o f r ew or ke d bi oc la st s c ou ld b e re la te d to tw o pr oc es se s: (i) th e sl ig ht re w or ki ng o f a ut oc ht ho no us e le m en ts su ch a s o ys te r s he lls ; o r ( ii) th e se di m en ta tio n of tr an sp or te d bi oc la st s f ro m p ro xi m al a re as . t hu s, ft 14 re fle ct s a sh or ef ac e en vi ro nm en t, un de r st or m in flu en ce . ft 15 . w hi tis h m ar ls lo w er m ar ls to ne -s he lly li m es to ne s u ni t a nd u pp er m ar ls to ne -s he lly li m es to ne s u ni t th e ft 15 c on si st s o f w hi tis h to li gh t g ra y, so ft m ar ls , 0 .2 – 2 .5 m -t hi ck (f ig . 5 f) . t he m ai n co m po ne nt s of th is fa ci es a re b iv al ve s, ga st ro po ds a nd ra re sm al l b ra ch io po ds . ba se d on th e lit ho lo gi ca l a nd fo ss il co nt en t, th is fa ci es is a tt rib ut ed to a n op en m ar in e se tt in g, w ith lo w e ne rg et ic co nd iti on s ( be n yo u ce f et a l., 2 01 7) . ta bl e 1. c on tin ue d g eologia c roatica naimi and cherif: sedimentology and ichnology of the mid-cretaceous succession of the ouled nail mounts (eastern saharan atlas, algeria) 217 area), including hysteroceras orbignyi, pervinquieria perinflata var. crassissima, scaphites hugardianus, stoliczkaia dovsedensis st. notha and turrilites tuberculatum, and indicating a late albian age (m. (mortoniceras) inflatum zone) (kieken, 1974). consequently, the maximum flooding surface related to the mid-cretaceous transgression in northern algeria (frenda-tiaret, ouled nail and hodna basins) is characterized by condensed mortoniceratinae-beds, which are diachronous, pointing to a late albian age sensu lato. 5. invertebrate trace fossils the mid-cretaceous succession of the djebel azzeddine section records a low diversity assemblage of trace fossils. six ichnogenera were recognized with abundant thalassinoides, common skolithos, and rare gyrolithes, oichnus, planolites and tisoa. except for thalassinoides and tisoa, it was impossible to identify specimens in the ichnospecies level. 5.1. gyrolithes isp. (fig. 6a) description: bioturbation structures described herein consist of vertical, sinistrally or dextrally spiraled burrows, corkscrewshaped, preserved as epichnial. these burrows are smooth and filled by dark and fine sediment in comparison with the host sediment. they are perpendicular to the bedding. coil diameter is 40 – 50 mm, and shaft diameteris 5 – 8 mm. delgadoi (fig. 3f). the studied specimens are considered to constitute the first record from algeria. this actaeonellid gastropod is a widespread middle to upper albian taxon, recorded from egypt, france, morocco and portugal (sohl & kollmann, 1985). a. delgadoi occurs in the dipoloceras (d.) cristatum and mortoniceras (m.) inflatum interval zones (el qot, 2018). in the uppermost part of the second unit, an ammonite-bearing level has been discovered for the first time in this part of ouled nail mounts, including mortoniceras sp., pervinquieria sp. and engonoceras sp. (fig. g-h). mortoniceras and pervinquieria species indicate the upper albian sensu lato, and co-occur in the m. (mortoniceras) pricei, m. (mortoniceras) inflatum and m. (mortoniceras) fallax zones (monod et al., 2000; kennedy et al., 2008; gale & kennedy, 2020). on the basis of this association (acteonella delgadoi, mortoniceras sp. and pervinquieria sp.), a part of the mid-cretaceous post-continental intercalaire marine deposits should correspond to the late albian. a similar ammonite-bearing bed has been documented in the late albian of the frenda-tiaret mounts (boualem, 2018), 300 km to the northwest of the djebel azzedine section. the ammonite fauna which yielded this level indicates the m. (mortoniceras) pricei and m. (mortoniceras) fallax condensation zones, named the mortoniceras event. the same glauconitic ammonitebearing level was recorded in the hodna (to the east of our study figure 6. invertebrate trace fossils from the upper albian – lower cenomanian of ouled nail mounts. (a) gyrolithes isp. (black arrow); (b) bivalve shell showing abundant oichnus isp.; (c) planolites isp. (black arrow) associated with undetermined concretionary burrows; (d) abundant skolithos isp. g eo lo gi a c ro at ic a geologia croatica 74/3218 occurrence: lower marlstone-shelly limestones unit. remarks: the ichnogenus gyrolithes constitutes a domichnion trace fossil produced by crustaceans in intertidal and shallow subtidal environments (gernant, 1972; dworschak & rodrigues, 1997; netto et al., 2007). it can also be produced by capitellid polychaetes (powell, 1977). gyrolithes occurs from the ediacaran – cambrian boundary (laing et al., 2018) to the holocene (wetzel et al., 2010), and indicates a marginal marine environment (gernant, 1972; powell, 1977; wetzel et al., 2010). this trace fossil is attributed to the skolithos and cruziana ichnofacies (pemberton et al., 2001). morphological features of the studied burrows resemble that of the ichnospecies g. lorcaensis uchman & hanken (2013) and g. polonicus fedonkin (1981). 5.2. oichnus isp. (fig. 6b) description: circular, sub-circular, oval to weakly elliptical, millimetre-sized borings in the tests of undetermined bivalves. they are perpendicular to the surface of the substrate, and shallower than wide. these borings are over 2 mm in maximum diameter. occurrence: lower marlstone-shelly limestone unit. remarks: bioerosion structures or borings occur in shallow marine biogenic substrates such as bivalve, brachiopod and echinoid shells (e.g., naimi et al., 2021c; vinn et al., 2021a). many small round holes (or drill holes) in shells are assigned to the ichnogenus oichnus which is produced essentially by predatory gastropods, particularly naticid gastropods (müller, 1969), known from the cambrian (vinn et al., 2021b) to the holocene (nielsen & nielsen, 2001), and belonging to the ichnofamily oichnidae (wisshak et al., 2019). oichnus is interpreted as an example of praedichnium (predation traces) with or without signs of attachment (wisshak et al., 2015; vallon et al., 2016). 5.3. planolites isp. (fig. 6c) description: epichnial burrows preserved in positive epirelief and oriented more or less parallel to the bedding. they consist of simple, unlined, straight, unbranched, slightly inclined burrows, 6 mm wide and 35 mm long. planolites isp. burrows are filled with yellow-red coarser-grained sandy material different from that of the host rock, which is finer and lighter, and co-occur with strong concretionary vertical undetermined burrows characterized by a similar fill. occurrence: upper marlstone-shelly limestones unit. remarks: the post-depositional trace fossil planolitesis interpreted as a feeding trace of vermiform deposit-feeders (uchman, 1995), arthropods and bivalves (knaust, 2017). it is considered as a cosmopolitan trace fossil known from the ediacaran, occurring in different aquatic environments in softgrounds (e.g., uchman, 1995; knaust, 2017; belaid et al., 2020). in a shallow marine setting, planolites commonly occurs in the cruziana ichnofacies (buatois & mángano, 2011). 5.4. skolithos isp. (fig. 6d) description: vertical to subvertical, unbranched, cylindrical and tabular burrows, preserved as endichnia. the burrow apertures at the bedding plane surface are circular to slightly oval. skoli­ thos isp. burrows usually completely penetrate the rock and are filled with a brownish sandy material with small recrystallized bioclasts. they are 2–13 mm in diameter, with a maximum length of about 120 mm. skolithos isp. co-occurs with thalassinoides isp. and dinosaur footprints. occurrence: upper marlstone-shelly limestones unit. remarks: the ichnogenus skolithos characterizes the littoral to shallow sublittoral skolithos ichnofacies (seilacher, 1967). it is created by suspension-feeding organisms such as anthozoans, crustaceans, holothurians, phoronids, polychaetes and priapulids for dwelling (domichnia) (knaust, 2017; knaust et al., 2018). skolithos burrows are generally associated with high hydrodynamic energy within shallow water environments (vinn & wilson, 2013). this trace fossil is known from the ediacaran (mccall, 2006) through to the holocene (dashtgard & gingras, 2012). 5.5. thalassinoides isp. (fig. 7a and b) description: systems of burrows consisting of horizontal tunnels and vertical or inclined cylindrical shafts. diameters of tunnels and shafts range from 10 to 30 mm. thalassinoides isp. burrows show yand t-shapes, and are filled with a brownish detrital material. occurrence: marlstone-algal bioturbated limestones unit and lower marlstone-shelly limestones unit. remarks: thalassinoides burrows occur in a shallow marine setting and represent a common constituent of the cruziana ichnofacies (benyoucef et al., 2012, 2019; cherif et al., 2015, 2018; belaid et al., 2020). they are known from the ordovician (ekdale & bromley, 2003) to the holocene (nickell & atkinson, 1995), and seem to be abundant within mesozoic and cenozoic strata (el-sabbagh et al., 2017). thalassinoides is considered as a fodinichnion-domichnion trace fossil produced by decapod crustaceans (frey et al., 1984). furthermore, palaeozoic thalassinoides may be produced by non-crustacean tracemakers (carmona et al., 2004). 5.6. t. paradoxicus woodward, 1830 (fig. 7c) description: t. paradoxicus is recorded for the first time from algeria. it is preserved in positive epichnia and hypichnia, mostly as hypichnia on the sole of the beds. t. paradoxicus is densely branched, subcylindrical to cylindrical burrows, highly irregular in size and morphology. the burrow system is multidirectional and oriented at various angles with respect to bedding, 20 – 80 mm in diameter, occurring as contorted nodules. the tunnels are horizontal, straight to slightly curved, whereas the bifurcations consist mostly of t-shaped intersections than y-shaped. the burrow filling is similar to that of the host material. occurrence: marlstone-algal bioturbated limestones unit. remarks: t. paradoxicus differs from the recorded t. sue­ vicus by its complex irregularly branching system, as well as the predominance of t-branches rather than y-shaped bifurcations. the studied t. paradoxicus branched system resembles that described in the middle miocene of egypt (el-sabbagh et al., 2017). it occurs in shallow siliciclastic deposits (knaust, 2020), especially in the middle shoreface (howard & frey, 1984) to foreshore (chrzastek et al., 2018), and suggests a low energy environment (mángano & buatois, 1991). t. para­ doxicus burrows are domichnion, documented in firmgrounds characterizing the glossifungites ichnofacies. they probably required firm, at least semi-consolidated substrates to prevent burrow collapse (myrow, 1995). 5.7. t. suevicus rieth, 1932 (fig. 7d) description: the studied thalassinoides suevicus are preserved in epichnia and endichnia, characterized by their complex irregg eologia c roatica naimi and cherif: sedimentology and ichnology of the mid-cretaceous succession of the ouled nail mounts (eastern saharan atlas, algeria) 219 ularly branching system. tunnels and shaft diameters vary from 5 to 24 mm, filled with a fine brown sandy material. thereby, dichotomous bifurcations are more common than t-shaped branches. occurrence: marlstone-algal bioturbated limestones unit. remarks: thalassinoides suevicus burrows support a subtidal environment (middle shoreface) (e.g., howard & frey, 1984). they characterize the soft grounds (myrow, 1995), within a shallow marine setting, with well-oxygenated water above the sea floor (naimi et al., 2020; naimi & cherif, 2021b). 5.8. cf. tisoa siphonalis de serres, 1840 (fig. 7e) description: it consists of a cylindrical, vertical u-shaped burrow, showing laminations within the passive burrow fill, the tube is filled by micritic material. the remaining portion of the wellpreserved tube is 30 mm long and 6 mm wide, constituting the long axis of a cylindrical calcareous concretion. occurrence: lower marlstone-shelly limestones unit. remarks: the difference between arenicolites and tisoa was discussed by knaust (2019). despite the close affinity between these trace fossils, the studied burrow has been attributed to cf. t. siphonalis due to the high length-width ratio and the presence of the calcareous concretion. the studied cf. tisoa siphona­ lis resembles the trace fossil annerepichnites walakhavasensis (sensu kulkarni & ghare, 1991), recorded from shallow marine bathonian – kimmeridgian sediments from india, and which has been recently attributed to tisoa siphonalis (knaust, 2019). the key feature of this trace is the presence of a laminated fill, which has been observed in the studied burrow. tisoa sipho­ nalis occurs in shallow to deep marine environments (knaust, 2017, 2019; cherif et al., 2021a, b), from the lower ordovician (pickerill & keppie, 1981) to the holocene (badve & ghare, 1984). ++ is interpreted as the result of dwelling activity (domichnion) of polychaetes (knaust, 2017), related to widespread authigenic seep carbonate formation (van de figure 7. invertebrate trace fossils from the upper albian – lower cenomanian of the ouled nail mounts. (a) thalassinoides isp. from unit a; (b) thalassinoides isp. associated with skolithos isp. from unit c; (c) thalassinoides paradoxicus network; (d) thalassinoides suevicus; (e) cf. tisoa siphonalis. g eo lo gi a c ro at ic a geologia croatica 74/3220 schootbrugge et al., 2010), and it is common in quasi-anoxic organic-rich and in cold seep deposits (knaust, 2019). in algeria, this ichnospecies has been reported from the lower miocene tiaret marl formation (cherif et al., 2021a) and the early cretaceous of the ouarsenis range (cherif et al., 2021b). 6. discussion 6.1. ichnological analysis the ichnoassemblage of the studied succession is composed of horizontal, vertical and inclined trace fossils constituting an impoverished example of the skolithos – glossifungites ichnofacies. it is dominated by domichnion, fodinichnion and praedichnion trace fossils produced mainly by worms, decapods and naticid gastropods. trace fossils of the lower part of the section correspond to a firmground suite of the glossifungites ichnofacies and they are represented essentially by thalassinoides paradoxicus. the t. paradoxicus rich bed (unit a) is characterized by low ichnodiversity, high abundance, and intense bioturbation which destroyed the primary sedimentary structures and the presence of branched burrow systems. these characteristics are typical of the substrate-controlled glossifungites ichnofacies (buatois & mángano, 2011). however, firmground burrowers may produce tisoa (knaust, 2017) and gyrolithes (netto et al., 2007). the typical examples of the glossifungites ichnofacies (archetypal glossifungites ichnofacies) are recorded in shallow to marginal marine environments; furthermore, surfaces containing this ichnofacies indicate transgressive events (buatois & mángano, 2011). the glossifungites ichnofacies occurs as a result of intense erosion in the zone of maximum wave energy of wave-dominated tidal flats (yang et al., 2009). the skolithos ichnofacies is well represented in the upper part of the section, mainly dominated by vertical, cylindrical, simple dwelling burrows of suspension-feeders, and characterized by the abundance of three-dimensional burrow systems dominated by vertical components, the absence of horizontal trace fossils produced by a mobile fauna, low ichnodiversity and variable abundance. skolithos constitutes the most common ichnogenus of the skolithos ichnofacies, well-known in nearshore settings. the dominance of vertical dwelling structures of infaunal suspension-feeders such as skolithos isp. indicates the high abundance of organic particles that are kept in suspension in the oxygenated water column by currents and waves (buatois & mángano, 2011). the predominance of vertical components over horizontal components indicates relatively high wave energy (howard & frey, 1984) related to stressful conditions. such situations can be indicated by the low ichnodiversity and the mono specific occurrences of skolithos isp. (mángano & buatois, 2004). in shallow marine water, the skolithos ichnofacies is typical of foreshore to upperand middle-shoreface environments, and it occurs in lower-intertidal flats depending on the tidal regime (buatois & mángano, 2011). several dinosaur footprints have been recorded in a similar setting. marginal marine carbonate sediments of a large innershelf environment, characterized by dolomitic sedimentation related to a warm and dry climate yielded theropod and ornithopod footprints from the barremian of portugal (santos et al., 2013). furthermore, tridactyl footprints which co-occur with bivalves and gastropods have been documented in dolomitic facies from the early jurassic of france (moreau et al., 2018). these tracks are associated with desiccation cracks and they indicate deposition within a periodically emergent environment. the invertebrate trace fossils and mud volcanoes recorded from these deposits allowed attribution of these track-bearing deposits to a subtidal to intersupratidal flat marsh. in northern africa, a similar ichnoassemblage including skolithos and dinosaur footprints (theropod, sauropod and ornithischian), reported torepresent a tidal flat, has been described from the mid-cretaceous of morocco (ibrahim et al., 2014). such a vertebrate-invertebrate ichnoassemblage has also been documented in a shallow-marine carbonate setting in the middle jurassic of wyoming (kvale et al., 2001). invertebrate trace fossils are dominated by vertical and cylindrical burrows attributed to the ichnogenus skolithos, indicating a soft-ground typical of an intertidal onshore facies persistent during formation of the dinosaur trackway. in the lower cretaceous of texas, dinosaur footprints are associated with a shallow invertebrate ichnofauna, suggesting a supratidal to shallow subtidal environment (farlow et al., 2012). 6.2. the mid-cretaceous transgression and palaeogeography the djebel azzeddine mid-cretaceous series could be correlated with the upper unit of the rhelida formation, which crops out in the ksour and djebel amour mounts, respectively in the western and central parts of the algerian saharan atlas. the rhelida formation transgressive deposits directly overlay the continental intercalaire and have been attributed firstly to the vraconnian (uppermost albian) (bassoullet, 1973). on the basis of new biostratigraphic data, as well as vertebrate remains from the rhelida formation equivalents in morocco (e.g., cavin et al., 2010), egypt (e.g., le loeuff et al., 2012), and the guir basin (southwestern algeria) (benyoucef et al., 2014, 2015, 2016), this formation has now been dated as lower – middle cenomanian (benyoucef et al., 2017). further north of the saharan atlas in the frenda-tiaret mounts (northern border of high plateaus), similar deposits defined as the mcharref formation dated as upper albian (boualem & benhamou, 2017) overlie the sidi ouadah formation, considered as the equivalent of the continental intercalaire (peybernès et al., 1986). the condensed ammonite bed [mortoniceras event sensu boualem (2018)] indicates a maximum flooding surface related to the late albian transgression (nagm & boualem, 2019). further west, in the daïa mounts, the equivalent of the albian continental intercalaire consists of the grès de bossuet formation (auclair & biehler, 1967). these fluvio-deltaic sediments are overlain by the late albian – cenomanian djebel tenfeld carbonate formation (auclair & biehler, 1967; ciszak, 1993), which yielded new ostracod species (damotte, 1984). the albian – lower cenomanian strata of the tellian atlas (northwestern algeria) are represented by turbidite-deposits and deep marl-limestone alternations (e.g., ciszak, 1993). it is concluded that the mid-cretaceous transgression is diachronous across northern algeria. it is precocious (late albian) in the eastern part of the saharan atlas (ouled nail basin) and the northern border of the oran high plateaus (daïa and frenda-tiaret basins), and more recent in the central and western parts of the saharan atlas (djebel amour and ksour basins). 7. conclusions new insights on the lithostratigraphy and the palaeoenvironment have been provided from the upper albian – lower cenomanian marine succession overlying the continental intercalaire in the eastern part of the ouled nail mounts (eastern algerian saharan g eologia c roatica naimi and cherif: sedimentology and ichnology of the mid-cretaceous succession of the ouled nail mounts (eastern saharan atlas, algeria) 221 atlas). the studied succession has been subdivided into three distinctive units: the marlstone-algal bioturbated limestones (unit a), lower marlstone-shelly limestones (unit b) and upper marlstone-shelly limestones (unit c). units a and b have been attributed to the upper albian on the basis of new recorded fossils. a typical lofer cyclothem with in situ slumped brecciation has been observed from the lowermost part of the section, reflecting local collapses of the carbonate platform. an ammonite-rich bed, discovered at the uppermost part of unit b including mortoniceratids and engonoceratids belonging to mortoniceras sp., pervinquieria sp. and engonoceras sp. has been recorded for the first time in the bou saada area. these ammonites indicate a maximum flooding surface of the mid-cretaceous transgression and could be correlated with similar levels from other algerian basins such as the frenda-tiaret and the hodna basins. unit c is barren of any biostratigraphic fauna, but has been assigned to the upper albian – lower cenomanian based on its position in the succession. the studied succession is characterized by a low ichnodiversity containing eight ichnotaxa such as: gyrolithes isp., planolites isp., skolithos isp., thalassinoides isp., t. paradoxicus, t. suevi­ cus, cf. tisoa siphonalis, and the boring oichnus isp. t. paradoxi­ cus and oichnus isp. are recorded for the first time from algeria. thalassinoides burrows are abundant, with common skolithos, and rare gyrolithes, oichnus, planolites and cf. tisoa. this ichnoassemblage is dominated by domichnion, fodinichnion and praedichnion trace fossils, and attributed to the skolithos and glossifungites ichnofacies.these trace fossils are produced mainly by decapod crustaceans, polychaetes and naticid gastropods. the sedimentological, palaeontological and ichnological data suggest an environment ranging from backshore (supratidal) to shoreface with a mixed (tide/storm) energy source. also, new small-sized tridactyl dinosaur footprints have been observed in unit c. considering the scarcity of diagnostic characters available we refrain from assigning these ichnites to specific ichnotaxa, and more accurate studies are required to proceed in that direction. acknowledgment we thank the managing editor t. fluksi (zagreb), the associate editor a. mezga (zagreb), m. antonelli (rome) and an anonymous reviewer for their comments and suggestions which improved this paper. we are especially grateful to d. bert (rennes) and w.j. kennedy (oxford) for the identification of the ammonite fauna. references amédro, f. (2008): support for a vraconnian stage between the albian sensu stricto and the cenomanian (cretaceous system).– carnets de géologie, 2008/02, 1–83. auclair, d. & biehler, j. (1967): etude géologique des hautes plaines oranaises entre tlemcen et saïda.– publications du service de la carte géologique de l’algérie, 34, 3–45. badve, r.m. & ghare, m.a. (1984): holocene trace fossils from beach rock of velas coast, raigad district, maharashtra.– biovigyanam, 10, 165–172. bassoullet, j.p. (1973): contribution à l’étude stratigraphique du mésozoïque de l’atlas saharien occidental (algérie). thèse de doctorat d’etat, université de paris vi, france, 497 p. belaid, m., cherif, a., vinn, o. & naimi, m.n. (2020): first record of trace fossils from the oxfordian argiles rouges de kheneg formation (tiaret, northwestern algeria).– geologia croatica, 73, 85–94. benyoucef, m., meister, c., bensalah, m. & malti, f.z. (2012): la plateforme préafricaine (cénomanien supérieur – turonien inférieur) dans la région de béchar (algérie): stratigraphie, paléoenvironnements et signification paléobiogéographiques.– revue de paléobiologie, 31, 205–218. benyoucef, m., adaci, m., meister, c., läng, e., malti, f.z., mebarki, k., cherif, a., zaoui, d., benyoucef, a. & bensalah, m. (2014): le « continental intercalaire » dans la région du guir (algérie): nouvelles données paléontologiques, ichnologiques et sédimentologiques.– revue de paléobiologie, 33, 281–297. benyoucef, m., läng, e., cavin, l., mebarki, k., adaci, m. & bensalah, m. (2015): overabundance of piscivorous dinosaurs (theropoda: spinosauridae) in the mid-cretaceous of north africa: the algerian dilemma.– cretaceous research, 55, 44–55. benyoucef, m., meister, c., mebarki, k., läng, e., adaci, m., cavin, l., malti, f.z., zaoui, d., cherif, a. & bensalah, m. (2016): evolution lithostratigraphique, paléoenvironnementale et séquentielle du cénomanian-turonien inférieur dans la région du guir (ouest algérien).– carnets de géologie, 16, 271–296. benyoucef, m., mebarki, k., ferré, b., adaci, m., bulot, l.g., desmares, d., villier, l., bensalah, m., frau, c., ifrim, c. & malti, f.z. (2017): lithoand biostratigraphy, facies patterns and depositional sequences of the cenomanian-turonian deposits in the ksour mountains (saharan atlas, algeria).– cretaceous research, 78, 34–55. benyoucef, m., zaoui, d., adaci, m., ferré, b., meister, c., piuz, a., el qot, g.m., mennad, a., tchenar, s. & bensalah, m. (2019): stratigraphic and sedimentological framework of the tinrhert plateau (cenomanianturonian, se algeria).– cretaceous research, 98, 95–121. bockelie, j.f. (1991): ichnofabric mapping and interpretation of jurassic reservoir rocks of the norwegian north sea.– palaios, 6, 206–215. boualem, n. (2018): géométrie de la sédimentation crétacée (albien – turonien) des monts de tiaret (frenda, chellala, nador…), corrélations et implications paléogéographiques.– thèse de doctorat ès-sciences, université d’oran 2, algeria, 253 p. boualem, n. & benhamou, m. (2017): mise en évidence d’un albien marin à céphalopodes dans la région de tiaret (algérie nord-occidentale) : nouvelles données paléontologiques, implications biostratigraphiques et paléogéographiques.– revue de paléobiologie, 36, 433–445. brandano, m., ronca, s. & di bella, l. (2020): erosion of tortonian phosphatic intervals in upwelling zones: the role of internal waves.– palaeogeography, palaeoclimatology, palaeoecology, 537, 109405. brossard, e. (1866): essai sur la constitution physique et géologique des régions méridionales de la subdivision de sétif (algérie).– mémoires du service géologique de la france, 2, 177–289. buatois, l.a. & mángano, m.g. (2011): ichnology: organism-substrate interactions in space and time.– cambridge university press, 358 p. butjor, l. (2010): systematics, phylogeny and homeomorphy of the engonoceratidae hyatt, 1900 (ammonoidea, cretaceous) and revision of engonoceras duboisi latil, 1989.– carnets de géologie, 2010/08, 1–31. cavin, l., tong, h., boudad, l., meister, c., piuz, a., tabouelle, j., aarab, m., amiot, r., buffetaut, e., dyke, g., hua, s. & le loeuff j. (2010): vertebrate assemblages from the early late cretaceous of southeastern morocco: an overview.– journal of african earth sciences, 57, 391–412. cherif, a., bert, d., benhamou, m. & benyoucef, m. (2015): la formation des argiles de saïda (jurassique supérieur) dans le domaine tlemcenien oriental (takhemaret, algérie): données biostratigraphiques, ichnologiques et sédimentologiques.– revue de paléobiologie, 34, 363–384. cherif, a., benyoucef, m., ferré, b. & benhamou, m. (2018): etude sédimentologique et ichnologique de la formation des argiles de saïda (jurassique supérieur) dans les monts de frenda (algérie nord-occidentale).– revue de paléobiologie, 37, 121–135. cherif, a., naimi, m.n. & belaid, m. (2021a): deep-sea trace fossils and depositional model from the lower miocene tiaret marl formation (northwestern algeria).– journal of african earth sciences, 175, 104115. cherif, a., benyoucef, m., naimi, m.n., ferré, b., zeghari, a., frau, c. & berrabah, a. (2021b): trace fossils from the berriasian–valanginian of the ouarsenis range (northwestern algeria) and their paleoenvironmental implications.– journal of african earth sciences, 180, 104219. chrząstek, a., muszer, j., solecki, a. & sroka, a.m. (2018): rosarichnoides sudeticus igen. et isp. nov. and associated fossils from the coniacian of the north sudetic synclinorium (sw poland).– geological quarterly, 62, 181–196. ciszak, r. (1993): evolution géodynamique de la chaîne tellienne en oranie (algérie occidentale) pendant le paléozoïque et le mésozoïque.– strata, 20, 1–513. damotte, r. (1984): ostracodes barrémiens-cénomaniens en algérie occidentale (coupe du djebel cheguiga, monts de daïa, oranie).– géologie méditerranéenne, 11, 159–172. dashtgard, s.e. & gingras, m.k. (2012): marine invertebrate neoichnology.– in knaust, d. & bromley, r.g. (eds.): trace fossils as indicators of sedimentary environments. elsevier, 273–295. g eo lo gi a c ro at ic a geologia croatica 74/3222 de serres, m. (1840): description de quelques mollusques fossiles nouveaux des terrains infra-jurassiques et de la craie compacte inférieure du midi de la france.– annales des sciences naturelles (zoologie), 2, 5–25. djebbar, t. (2000): structural evolution of the algerian saharan atlas.– phd thesis, royal holloway university of london, united kingdom, 373 p. dworschak, p.c. & rodrigues, s.d.a. (1997): a modern analogue for the trace fossil gyrolithes: burrows of the thalassinidean shrimp axianassa australis.– lethaia, 30, 41–52. ekdale, a.a. & bromley, r.g. (2003): paleoethologic interpretation of complex thalassinoides in shallow-marine limestones, lower ordovician, southern sweden. palaeogeography, palaeoclimatology, palaeoecology, 192, 221–227. el qot, g.m. (2018): aptian-early cenomanian ammonites from north sinai, egypt: systematic paleontology and biostratigraphy.– cretaceous research, 85, 142–171. el-sabbagh, a., el-henedy, m. & al farraj, s. (2017): thalassinoides in the middle miocene succession at siwa oasis, northwestern egypt.– proceedings of the geologists’ association, 128, 222–233. emberger, j. (1960): esquisse géologique de la partie orientale des monts des ouled naïl.– publications du service de la carte géologique de l’algérie, 27, 1–398. farlow, j.o., o’brien, m., kuban, g.j., dattilo, b.f. & bates, k.t. (2012): dinosaur tracksites of the paluxy river valley (glen rose formation, lower cretaceous), dinosaur valley state park, somervell country, texas.– actas de v jornadas internacionales sobre paleontología de dinosaurios y suentorno, salas de los infantes, burgos, 41–69. fedonkin, m.a. (1981): belomorskaya biota venda (dokembriyskaiabesskeletnaya fauna severarusskoyplatformi). geologicheskiyaei institute akademieyya sciences.– nauka, moskva, 342, 1–100. ferré, b., mebarki, k., benyoucef, m., villier, l., bulot, l.g., desmares, d., benachour, h.b., marie, l., sauvagnat, j., bensalah, m., zaoui, d. & adaci, m. (2017): roveacrinids (crinoidea, roveacrinida) from the cenomanian-turonian of southwest algeria (saharan atlas and guir basin).– annales de paléontologie, 103, 185–196. fischer, a.g. (1964): the lofer cyclothems of the alpine triassic.– in merriam, d.f. (eds.): symposium on cyclic sedimentation.– kansas geological survey bulletin, 169, 107–146. gale, a.s. & kennedy, w.j. (2020): upper albian ammonites from north-east texas.– revue de paléobiologie, 39, 1–139. gernant, r.e. (1972): the paleoenvironmental significance of gyrolithes (lebensspur).– journal of paleontology, 46, 735–741. grosheny, d., chikhi-aouimeur, f., ferry, s., benkherouf-kechid, f., jati, m., atrops, f. & redjimi-bourouiba, w. (2008): the upper cenomanian-turonian (upper cretaceous) of the saharan atlas (algeria).– bulletin de la société géologique de france, 179, 593–603. grun, t.b., kroh, a. & nebelsick, j.h. (2017): comparative drilling predation on time-averaged phosphatized and nonphosphatized assemblages of the minute clypeasteroid echinoid echinocyamus stellatus from miocene offshore sediments (globigerina limestone formation, malta).– journal of paleontology, 91, 633–642. guiraud, r. (1973): evolution post-triasique de l’avant-pays de la chaîne alpine en algérie, d’après l’étude du bassin du hodna et des régions voisines.– thèse de doctorat ès-sciences, université de nice, france, 270 p. halamski, a.t. & cherif, a. (2017): oxfordian brachiopods from the saïda and frenda mountains (tlemcenian domain, north-western algeria).– annales societatis geologorum poloniae, 87, 141–156. hancock, j.m. & kauffman, e.g. (1979): the great transgressions of the late cretaceous.– journal of the geological society of london, 136, 175–186. herkat, m. (1999): la sédimentation de haut niveau marin du crétacé supérieur de l’atlas saharien oriental et des aurès. stratigraphie séquentielle, analyse quantitative des biocénoses, évolution paléogéographique et contexte géodynamique.– thèse de doctorat, usthb, algiers, algeria, 802 p. herkat, m. & guiraud, r. (2006): the relationships between tectonics and sedimentation in the late cretaceous series of the eastern atlasic domain (algeria).– journal of african earth sciences, 46, 346–370. howard, j.d. & frey, r.w. (1984): characteristic trace fossils in nearshore to offshore sequences, upper cretaceous of east-central utah.– canadian journal of earth sciences, 21, 200–219. iannace, a., frijia, g., calluccio, l. & parente, m. (2014): facies and early dolomitization in upper albian shallow-water carbonates of the southern apennines (italy): paleotectonic and paleoclimatic implications.– facies, 60, 169–194. ibrahim, n., varricchio, d.j., sereno, p.c., wilson, j.a., dutheil, d.b., martill, d.m., baidder, l. & zouhri, s. (2014): dinosaur footprints and other ichnofauna from the cretaceous kem kem beds of morocco. plos one, 9, e90751. kazi-tani, n. (1986): evolution géodynamique de la bordure nord-africaine: le domaine intraplaque nord-algérien. approche mégaséquentielle.– thèse de doctorat ès-sciences, université de pau et des pays de l’adour, france, 871 p. kennedy, w.j., jagt, j.w.m., amédro, f. & robaszynski, f. (2008): the late albian (mortoniceras fallax zone) cephalopod fauna from the bracquegnies formation at strépy-thieu (hainaut, southern belgium).– geologica belgica, 11, 35–69. kieken, m. (1974): etude géologique du hodna, du titteri et de la partie occidentale des biban (dépt. d’alger – algérie).– publications du service géologique de l’algérie, 46, 1–217. knaust, d. (2017): atlas of trace fossils in well core: appearance, taxonomy and interpretation. springer, dordrecht, 209 p. knaust, d. (2019): the enigmatic trace fossil tisoa de serres, 1840.– earth-science reviews, 188, 123–147. knaust, d. (2020): the paradoxical ichnotaxonomy of thalassinoides paradoxicus: a name of different meanings. palz, https://doi.org/10.1007/s12542-020-00520-z. knaust, d., thomas, r.d.k. & curran, h.a. (2018): skolithos linearis haldeman, 1840 at its early cambrian type locality, chickies rock, pennsylvania: analysis and designation of a neotype.– earth-science reviews, 185, 15–31. kowalke, t. & bandel, k. (1996): systematikundpaläoökologie der küstenschnecken der nordalpinenbrandenberg-gosau (oberconiac/untersanton) mit einem vergleichzurgastropodenfauna des maastrichts des trempbeckens (südpyrenäen, spanien). mitteilungen der bayerischenstaatssammlungfürpaläontologieundhistorischegeologie, 36, 15–71. kulkarni, k.g. & ghare, m.a. (1991): locomotory traces (repichnia) from the jurassic sequence of kutch, gujarat.– journal of the geological society of india, 37, 374–387. kvale, e.p., johnson, g.d., mickelson, d.l., keller, k., furer, l.c. & archer, a.w. (2001): middle jurassic (bajocian and bathonian) dinosaur mega tracksites, bighorn basin, wyoming, u.s.a.– palaios, 16, 233–254. laing, b.a., buatois, l.a., mángano, m.g., narbonne, g.m. & gougeon, r.c. (2018): gyrolithes from the ediacaran-cambrian boundary section in fortune head, newfoundland, canada: exploring the onset of complex burrowing.– palaeogeography, palaeoclimatology, palaeoecology, 495, 171–185. le loeuff j., läng, e., cavin, l. & buffetaut, e. (2012): between tendaguru and bahariya: on the age of the early cretaceous dinosaur sites from the continental intercalaire and other african formations.– journal of stratigraphy, 36, 1–18. mángano, m.g. & buatois, l.a. (1991): discontinuity surfaces in the lower cretaceous of the high andes (mendoza, argentina): trace fossils and environmental implications.– journal of south american earth sciences, 4, 215–229. mángano, m.g. & buatois, l.a. (2004): ichnology of carboniferous tide-influenced environments and tidal flat variability in the north american midcontinent.– in mcilroy, d. (eds.): the application of ichnology to palaeoenvironmental and stratigraphic analysis. geological society special publication, 228, 157–178. marenssi, s.a., santillana, s.n. & rinaldi, c.a. (1998): stratigraphy of the la meseta formation (eocene), marambio (seymour) island, antarctica.– asociación paleontológica argentina, publicación especial, 5, 137–146. mccall, g.j.h. (2006): the vendian (ediacaran) in the geological record: enigmas in geology’s prelude to the cambrian explosion.– earth-science reviews, 77, 1–229. mebarki, k., sauvagnat, j., benyoucef, m., zaoui, d., benachour, h.b., adaci, m., mahboubi, m. & bensalah, m. (2016): ostracodes cénomano-turoniens dans l’atlas saharien occidental et le bassin du guir (sud-ouest de l’algérie): systématique, biostratigraphie et paléobiogéographie.– revue de paléobiologie, 35, 249–277. mennad, a., tabuce, r., guinot, g., sarr, r., benyoucef, m., bensalah, m., cappetta, h., charrière, a. & adaci, m. (2020): découverte d’une nouvelle faune d’âge cénomanien dans la région de forthassa (atlas saharien occidental, algérie): implications biostratigraphiques et paléoenvironnementales.– annales de paléontologie, 106, 102355. monod, o., busnardo, r. & guerrero-suastegui, m. (2000): latealbian ammonites from the carbonate cover of the teloloapan arc volcanicrocks (guerrero state, mexico).– journal of south american earth sciences, 13, 377–388. moreau, j.d., trincal, v., andré, d., baret, l., jacquet, a. & wienin, m. (2018): underground dinosaur tracksite inside a karst of southern france: early jurassic tridactyl traces from the dolomitic formation of the malaval cave (lozère).– international journal of speleology, 47, 29–42. müller, a.h. (1969): zurökologie und biostratinomieeinesechinocorys (echinoidea) miteigentümlichemnaticiden-befall aus der oberkreide.– monatsberichte der deutschen akademie der wissenschaftenzu berlin, 11, 672–684. myrow, p.m. (1995): thalassinoides and the enigma of early paleozoic open-framework burrow systems.– palaios, 10, 58–74. nagm, e. & boualem, b. (2019): first documentation of the late albian transgression in northwest algeria: bivalve stratigraphy and palaeobiogeography.– cretaceous research, 93, 197–210. naimi, m.n. & cherif, a. (2021a): inventory and assessment of significant scientific algerian geoheritage: case of remarkable geosites from orania (western algeria).– international journal of geoheritage and parks, 9, 13–29. g eologia c roatica naimi and cherif: sedimentology and ichnology of the mid-cretaceous succession of the ouled nail mounts (eastern saharan atlas, algeria) 223 naimi, m.n. & cherif, a. (2021b): ichnological analysis of the late miocene shallow marine diatomaceous deposits of the lower chelif basin (northwestern algeria): paleoenvironmental insights and comparison with deep diatomites.– journal of african earth sciences, 180, 104239. naimi, m.n., mansour, b., cherif, a., chekkali, m.c., benkhedda, a. & belaid, m. (2020): lithostratigraphie et paléoenvironnements des dépôts messiniens de la terminaison nord-orientale des monts des ouled ali (bassin du bas chélif, algérie nord-occidentale).– revue de paléobiologie, 39, 467–483. naimi, m.n., mahboubi, c.y. & cherif, a. (2021a): lithostratigraphy and evolution of the lower cretaceous basins, in western saharan atlas, algeria: a comment.– journal of african earth sciences, 183, 104304. naimi, m.n., vinn, o., cherif, a. & benyoucef, m. (2021b): trypanites and associated bivalve borings in an upper albian hardground from the eastern saharan atlas (algeria).– proceedings of the geologists’ association. naimi, m.n., vinn, o. & cherif, a. (2021c): bioerosion in ostrea lamellosa shells from the messinian of the tafna basin (nw algeria).– carnets de géologie, 21, 127–135. netto, r.g., buatois, l.a., mángano, m.g. & balistieri, p. (2007): gyrolithes as a multipurpose burrow: an ethologic approach. revista brasileira de paleontologia, 10, 157–168. nickell, l.a. & atkinson, r.j.a. (1995): functional morphology of burrows and trophic modes of three thalassinidean shrimp species, and a new approach to the classification of thalassinidean burrow morphology.– marine ecology progress series, 128, 181–197. nielsen, k.s.s. & nielsen, j.k. (2001): bioerosion in pliocene to late holocene tests of benthic and planktonic foraminiferans, with a revision of the ichnogenera oichnus and tremichnus.– ichnos, 8, 99–116. özer, s. & benyoucef, m. (2021): late cenomanian rudists from southern algeria: descriptions, biostratigraphy, palaeoecology and palaeobiogeography.– cretaceous research, 118, 104639. pemberton, s.g., spila, m., pulham, a.j., saunders, t., maceachern, j.a., robbins, d. & sinclair, i.a. (2001): ichnology and sedimentology of shallow to marginal marine systems: ben nevis & avalon reservoirs, jeanne d’arc basin.– geological association of canada short course notes, 15, 1–343. péron, a. (1883): essai d’une description géologique de l’algérie. editions masson, paris, 202 p. peybernès, b., ciszak, r. & cugny, p. (1986): la transgression mésocrétacée sur le haut-fond de saïda (avant-pays tellien, algérie occidentale).– bulletin de la société d’histoire naturelle de toulouse, 122, 51–63. pickerill, r.k. & keppie, j.d. (1981): observations on the ichnology of the meguma group (? cambro-ordovician) of nova scotia.– maritime sediments and atlantic geology, 17, 130–138. powell, e.n. (1977): the relationship of the trace fossil gyrolithes (= xenohelix) to the family capitellidae (polychaeta).– journal of paleontology, 51, 552–556. rieth, a. (1932): neue fundespongeliomorpherfucoidenaus dem jura schwabens.– geologische und paläontologischeabhanlungen, 19, 257–294. ritter, e. (1902): le djebel amour et les monts des oulad-nayl. bulletin du service de la carte géologique de l’algérie, 2, 1–97. salhi, a., atrops, f. & benhamou, m. (2020): le passage cénomanien-turonien dans les monts des ksour (atlas saharien occidental, algérie): biostratigraphie, géochimie et milieux de depot.– estudios geológicos, 76, e135. santos, v.f., callapez, p.m. & rodrigues, n.p.c. (2013): dinosaur footprints from the lower cretaceous of the algarve basin (portugal): new data on the ornithopod palaeoecology and palaeobiogeography of the iberian peninsula.– cretaceous research, 40, 158–169. scotese, c.r. (2013): map folio 23, early cretaceous (late albian, 101.8 ma). paleomap paleoatlas for arcgis, volume 2, cretaceous paleogeographic, paleoclimatic and plate tectonic reconstructions.– paleomap project, evanston, ii. seilacher, a. (1967): bathymetry of trace fossils.– marine geology, 5, 413–428. shinn, e.a. (1983): birdseyes, fenestrae, shrinkage pores, and loferites: a reevaluation.– journal of sedimentary petrology, 53, 619–628. sohl, n.f. & kollmann, h.a. (1985): cretaceous actaeonellid gastropods from the western hemisphere.– geological survey professional paper, 1304, 1–104. strasser, a. (1991): lagoonal-peritidal sequences in carbonate environments: autocyclic and allocyclic processes.– in einsele, g., ricken, w. & seilacher, a. (eds.): cycles and events in stratigraphy. springer-verlag, berlin, 709–721. uchman, a. (1995): taxonomy and palaeoecology of flysch trace fossils: the marnoso-arenacea formation and associated facies (miocene, northern apennines, italy).– beringeria, 15, 3–115. uchman, a. & hanken, n.m. (2013): the new trace fossil gyrolithes lorcaensis isp. n. from the miocene of se spain and a critical review of the gyrolithes ichnospecies.– stratigraphy and geological correlation, 21, 312–322. vallon, l.h., rindsberg, a.k. & bromley, r.g. (2016): an updated classification of animal behaviour preserved in substrates.– geodinamica acta, 28, 5–20. van de schootbrugge, b., harazim, d., sorichter, k., oschmann, w., fiebig, j., püttmann, w., peinl, m., zanella, f., teichert, b.m.a., hoffmann, j., stadnitskaia, a., rosenthal,y. (2010): the enigmatic ichnofossil tisoa siphonalis and widespread authigenic seep carbonate formation during the late pliensbachian in southern france.– biogeosciences, 7, 3123–3138. vinn, o. & wilson, m.a. (2013): an event bed with abundant skolithos burrows from the late pridoli (silurian) of saaremaa (estonia).– carnets de géologie, cg2013_l02, 83–87. vinn, o., naimi, m.n. & cherif a. (2021a): the endobiontic serpulids in corals and other reef associated fauna from the messinian of algeria.– neues jahrbuch für geologie und paläontologie, 300, 235–244. vinn, o., holmer, l.e., wilson, m.a., isakar, m. & toom, u. (2021b): possible drill holes and pseudoborings in obolid shells from the cambrian/ordovician boundary beds of estonia and the uppermost cambrian of nw russia. historical biology, in press. https://doi.org/10.1080/08912963.2021.1878355. wetzel, a., tjallinjii, r. & stattegger, k. (2010): gyrolithes in holocene estuarine incised-valley fill deposits, offshore southern vietnam.– palaios, 25, 239–246. wisshak, m., kroh, a., bertling, m., knaust, d., nielsen, j.k., jagt, j.w.m., neumann, c. & nielsen, k.s.s. (2015): in defence of an iconic ichnogenus – oichnus bromley, 1981.– annales societatis geologorum poloniae, 85, 445–451. wisshak, m., knaust, d. & bertling, m. (2019): bioerosion ichnotaxa: review and annotated list.– facies, 65, 24. woodward, s. (1830): a synoptic table of british organic remains, i–xiii.– longman & john stacy, london, 1–50. yang, b., dalrymple, r.w., gingras, m.k. & permberton, s.g. (2009): autogenic occurrence of glossifungites ichnofacies: examples from wave-dominated macrotidal flats, southwestern coast of korea.– marine geology, 260, 1–5. g eo lo gi a c ro at ic a geologia croatica 74/3224 www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2025 | 78/3 | 185–204 | 12 figs. | 1. introduction the middle – late anisian depositional history in the western tethys realm reflects the opening of the neo-tethys ocean and is reflected in a) a break-up unconformity (horst-andgraben morphology) and b) the drowning of the shallow-water carbonate ramp of the ravni formation (sudar et al., 2013 and references therein). this remarkable turnover (reifling turnover: schlager & schöllnberger, 1974) marks the change from deposition in a continental graben to deposition on the passive continental margin (gawlick & missoni, 2019 and references therein) of the newly formed neo-tethys ocean in the sense of suess (1888, 1901). in the dinarides, the general depositional evolution of this drowning history, that is the drowning of the ravni carbonate ramp and its overlying red nodular limestones, or mass-transport deposits of the bulog group has been known since the 19th century (sudar et al., 2023a and references therein). a general deepening trend during deposition of the bulog group has been known since kittl (1904), but was never studied in detail (compare sudar et al., 2013 and references therein). even if a lot of stratigraphic details have been obtained since kittl (1904), especially regarding the biostratigraphic age of the bulog limestone (e.g. vinassa de regny, 1903; from deep-marine stratigraphic condensation to mass-transport deposition: illyrian stepwise extension recorded in a red nodular limestone drowning sequence (bulog formation) of the ravni carbonate ramp (seljani area, montenegro) milica mrdak1,2,*, hans-jürgen gawlick2, nevenka djerić1, ioan i. bucur3,4, eva wegerer2, martin đaković5, milan sudar6 1 university of belgrade, faculty of mining and geology, đušina 7, 11000 belgrade, serbia; (*corresponding author: mrdak.milica@yahoo.com) 2 montanuniversität leoben, department applied geosciences and geophysics, energy geosciences, peter tunner strasse 5, 8700 leoben, austria 3 babeş-bolyai university, department of geology and center for integrated geological studies, m. kogălniceanu str. 1, 400084 cluj-napoca, romania 4 romanian academy, cluj branch, 9, republicii street, 400015 cluj-napoca, romania 5 geological survey of montenegro, jaglike adžić bb, 81000 podgorica, montenegro 6 serbian academy of sciences and arts, knez-mihailova 35, 11000 belgrade, serbia doi: 10.4154/gc.2025.13 abstract new biostratigraphic data obtained by studying ammonoids, calcareous algae, conodonts, and foraminifera from the westernmost part of the east bosnian – durmitor mega-unit in northern montenegro, result in a detailed reconstruction of the middle – late anisian (pelsonian-illyrian) subsidence history related to tectonic motions. two independent times of extension with formation of a horst-and-graben structure and neptunian dikes can be distinguished. during the first phase of extension, a rapid deepening of the footwall block during late pelsonian times can be recognized. the initial late pelsonian deepening is characterized by the formation of neptunian dikes in the older pelsonian shallow-water limestones, which are filled with open-marine red micrite showing a microfacies typical for shallow deepswells. this initial phase is only preserved in the infilling of neptunian dikes and represents the onset of the drowning sequence. the final late pelsonian depositional deep-swell environment is preserved in a level with stratigraphic condensation, but a deep-water microfacies. the second (late illyrian) deepening also resulted in the formation of neptunian dikes, a horst-and-graben topography, and the mobilization of mass-transport deposits related to the onset of intense volcanism. martelli, 1904, 1906; salopek, 1911; fischer & jacobshagen, 1976; sudar, 1986; sudar et al., 2023a, b and references therein), several open questions remain. important open questions are still related to the relative water depth of the newly created basins and horsts and their complicated subsidence history during the formation of the horst-and-graben topography, even though it is known that the water depth of these basins did not exceed a few hundred metres (gawlick et al., 2012). furthermore, the recently detected stepwise deepening with at least two independent stages of creation of a horst-and-graben topography in a) the late pelsonian, and b) around the middle/late illyrian boundary, with time-equivalent formation of neptunian dikes and deposition of mass-transport deposits (gawlick et al., 2023; sudar et al., 2023a, b; mrdak et al., 2024a and references therein), is still not fully understood throughout the dinarides. while triassic sediments, all belonging to the outer dinarides (schmid et al., 2008, 2020: east bosnian – durmitor mega-unit = inner dinarides) cover more than the half of the total territory of montenegro, understanding of their deposition through time and space is still rather weak. until recently, it was believed that deposition in the triassic was more or less continuous (dimitrijević, 1997; kovács et al., 2010, article history: manuscript received: february 24, 2025 revised manuscript accepted: may 8, 2025 available online: october 20, 2025 keywords: anisian, palaeogeography, conodonts, dinarides, microfacies g eo lo gi a c ro at ic a 186 geologia croatica 78/3 2014) and that huge shallow-water carbonate platforms were formed continously during middle – late triassic times in the outer dinarides, only disconnected by some intraplatform basins with continous deep-water sedimention (lim basin, bosnian basin: aubouin et al., 1970; rampnoux, 1974; charvet, 1978, 1980). the last important studies on the various triassic lithologies (bešić, 1936; pantić, 1967; rampnoux, 1974; mirković, 1983; dimitrijević, 1997 and references therein) lack modern microfacies and micropaleontological age dating. only in the area of the budva unit have several modern studies been carried out (summarized in goričan et al., 2022). new studies demonstrated that autochthonous triassic deep-water basins in between the carbonate platforms never existed in the dinarides (gawlick et al., 2017a, b, 2018; gawlick & missoni, 2019; sudar et al., 2025). furthermore, several tectonic events, volcanism as well as biological crises affected the believed continuous deposition, resulting in cases in a very heterogenous topography and the repeated demise of shallow-water carbonate production, in cases expressed as long-lasting stratigraphic gaps (missoni & gawlick, 2012; sudar et al., 2013; gawlick et al., 2017a; mrdak et al., 2023, 2024a). analysis of the neptunian dike and sill infillings (for details see wendt, 2017 and references therein) which occur in the middle pelsonian ravni formation provide overlooked insights in the depositional history of the drowning sequence above the ravni carbonate ramp. in such dikes/sills, sediments can be preserved which often cannot be recognized in the normal overlying succession. such infillings can therefore fill a gap in knowledge in the depositional history triggered by extension and subsequent rapid subsidence after the demise of shallow-water carbonate production. in the westernmost part of the east bosnian – durmitor mega-unit (fig. 1) in the village of seljani (plužine), an anisian section composed of the ravni formation with two generations of neptunian dikes and the overlying bulog formation was investigated in respect of their biostratigraphic age by conodont and ammonite dating, and their depositional environment using microfacies analysis. this paper aims to describe the evolution of a rapidly subsiding footwall block as part of the break-up unconformity and subsequent deposition on a deepmarine swell during late pelsonian to middle illyrian times. around the middle/late illyrian boundary, parts of the deep swell were affected by a second pulse of extension after the onset of volcanism. former horsts were flooded and dissected by normal faults, the deep-marine swell received reworked material, and further deepening. this history is documented based on microfacies analysis, xrd-analysis, the diagenetic overprint using the conodont colour alteration index (cai), and biostratigraphic age dating based on algae, foraminifera, conodonts, and ammonoids. 2. geological and stratigraphic setting the studied section at seljani (fig. 1, fig. 2, gps coordinates of the section: from 43°05´23.59´´n/18°50´53.26´´e to 43°05´22.14´́ n/18°50´54.52´́ e), is located west of the east bosnian – durmitor mega-unit (dimitrijević, 1997; schmid et al., 2008) (fig. 1) in an isolated thrust sliver. in it ś frontal part the east bosnian – durmitor mega-unit, i.e. the durmitor nappe (hrvatović, 2006), was imbricated during palaeogene thrusting and overrode the pre-karst + bosnian “flysch“ unit (schmid et al., 2008, 2020), i.e. the sarajevo sigmoid in the sense of dimitrijević (1997) or the kuči unit in sense of mirković (1980). according to mirković (1980) and mirković et al. (1979) this tectonic sliver with the studied section seljani does not belong to the east bosnian – durmitor mega-unit and should be an uplifted part of the easternmost pre-karst + bosnian “flysch“ unit, i.e. the kuči unit. in the view of the triassic arrangement of the facies zones, the study area has a closer palaeogeographic affinity to the east bosnian – durmitor mega-unit than to the pre-karst + bosnian “flysch“ unit. in the triassic the palaeogene east bosnian – durmitor mega-unit (or nappe) and the pre-karst + bosnian “flysch“ unit and the adjacent high karst unit (fig. 1) were a part of the same southwest – northeast trending depositional belt. in its eastern part, the triassic sequence of the pre-karst unit is covered by jurassic to palaeogene sedimentary rocks, and therefore nothing is known about their facies due to the lack of outcrops. however, we attribute the study area to be a part of the east bosnian – durmitor mega-unit sensu lato and not to the pre-karst + bosnian “flysch“ unit. in a different interpretation, the sarajevo sigmoid (dimitrijević, 1997) or kuči unit (mirković, 1980) in figure 1. overall tectonic map of the dinarides in bosnia and herzegovina, serbia, montenegro, and adjacent countries, redrawn after schmid et al. (2008, 2020), sudar et al. (2023a), based on new results (gawlick et al., 2017a, 2023; radivojević, 2023; djerić et al., 2024). red star indicates the studied section at seljani. g eologia c roatica 187mrdak et al.: from deep-marine stratigraphic condensation to mass-transport deposition: illyrian stepwise extension recorded in a red nodular ... its easternmost part should belong to the so-called bosnian zone (goričan et al., 2022 and references therein). this tectonic zone should be characterized by a middle – late triassic (to jurassic – cretaceous) continous deep-water evolution and should strike from bosnia – herzegovina (sarajevo area) via montenegro to albania and greece (see charvet et al., 1974; charvet, 1978; rampnoux, 1974; cadet, 1976). charvet et al. (1974) and charvet (1978, 1980) assigned the region around sarajevo with bulog and hallstatt limestones as part of the “zone bosniaque + zone serbe in parts”, and correlated this zone with the mirdita zone in albania and the zone maliaque? in greece (compare dercourt et al., 1993). south of sarajevo, charvet (1980) placed the areas with triassic deep-water sedimentary rocks into the internal zone bosniaque and the zone serbe, interpreted as an autochthonous deep-water basin between the durmitor and the high karst/pre-karst (see blanchet et al., 1970). this autochthonous model of long-lasting middle – late triassic deep-water basins between shallow-water carbonate platforms is disproved in bosnia – herzegovina (sudar et al., 2025), serbia (gawlick et al., 2017a, b, 2018), montenegro (goričan et al., 2022; mrdak et al., 2024b), albania (gawlick et al., 2008; gawlick & missoni, 2019), and greece (kostaki et al., 2024). in fact all these middle – late triassic deep-water sequences represent allochthonous far-travelled units from the east, resting as nappes or mélanges on parauchthonous units with late triassic shallow-water carbonates (fig. 3). a current controversial discussion centres on how to use the terms middle illyrian or late illyrian. the aplococeras avisianum zone is presently included in many ammonoid zonations as the youngest subzone of the reitziites reitzi zone (balini et al., 2010; jenks et al., 2015) of the middle illyrian. while the conodonts of this age are mainly described as late illyrian, to correlate the ammonoid and conodont zonations, the first appearance datum (fad) of aplococeras avisianum figure 2. a geographic sketch map of montenegro with the location of the studied section at seljani in northern montenegro (see also fig. 1); b the seljani section is approximately 5 km south of the city of plužine (compare bešić, 1949a, b); c detailed topographic map with position of the studied section. g eo lo gi a c ro at ic a 188 geologia croatica 78/3 (mojsisovics) could be proposed as the base of the late illyrian, as was previously done in the bagolino section for the base of the ladinian by mietto et al. (2003). in this sense, faunas with aplococeras avisianum (mojsisovics) should be considered a separate zone. for geological reasons and correlation with other organism groups (e.g. conodonts, radiolarians – krystyn, 1983; kozur, 2003) we plead for an independent aplococeras avisianum zone which should be incorporated into the late illyrian. for a more detailed discussion see mrdak et al. (2024a) and đaković et al. (2025). the geographic position of the studied section is plotted into the stratigraphic table for the triassic comprising the inner dinarides to the east bosnian – durmitor mega-unit (fig. 3). note, that the stratigraphic evolution of the pre-karst unit in the triassic is quite similar to that of the east bosnian – durmitor mega-unit, both belonging to the outer dinarides. 3. methods and samples twelve important and indicative samples are highlighted in figure 4. a panalytical x'pert3 powder diffractometer (chair of energy geoscience – montanuniversität leoben) with a cu anode measuring from 0° – 90° was used for xrd measurements to investigate the volcanic ash sample. a copper anode was used as the radiation source to generate the lowfigure 3. triassic stratigraphic table of the inner to outer dinarides, modified after gawlick et al. (2017a, 2023) and gawlick & missoni (2019). early triassic to early middle triassic modified after dimitrijević (1997) and jovanović (1998). generation of neo-tethys oceanic crust started around the middle/late anisian boundary, contemporaneously with the drowning of the ravni/steinalm carbonate ramp. for description, definition and emendation of several formations see sudar et al. (2013), sudar & gawlick (2018), gawlick et al. (2017a, 2023), and sudar et al. (2023a, b; 2025). the geometric arrangement of the different formations is in accordance with the late triassic carbonate platforms and passive continental margin configuration after gawlick et al. (2008, 2016), and is also characteristic for the different defined tectonic units in the dinarides (fig. 1). the position of the studied section at seljani is indicated by the red box. g eologia c roatica 189mrdak et al.: from deep-marine stratigraphic condensation to mass-transport deposition: illyrian stepwise extension recorded in a red nodular ... energy x-rays, and a characteristic line spectrum (kα and kβ components) was emitted under a high voltage of 40 kv and a current of 40 ma. monochromators were used to reduce the k component to the kα1 wavelength. the acquired angular range was between 2.51°2ɵ and 65.99°2ɵ, the step size of the measurements covered 0.0167°ɵ, and the goniometer speed was 0.5°2ɵ/minute. microfacies analysis was carried out according to flügel (2004). conodonts were used for biostratigraphy and estimation of the diagenetic overprint using the conodont colour alteration index (cai) method (epstein et al., 1977; rejebian et al., 1987). seven conodont-bearing samples (4.3 – 4.7 kg each, fig. 4) were dissolved in acetic acid (ca. 8%) to avoid any influence on the conodont apatite by the dissolution process. residue was dried at a max. of 50 °c to avoid any influence on the cai or internal structure or colour of the conodonts. cai-values were visually determined using a standard set and following the classification schemes of epstein et al. (1977) and rejebian et al. (1987), see also gawlick et al. (1994). the number of isolated specimens from the processed samples varied between 20 and 130. a keyence digital-microscope vhx 6000 (chair of geology and economic geology –montanuniversität leoben) was used to photograph the specimens. the biostratigraphic age dating of the revised and newly studied sections follow the slightly revised conodont biostratigraphic age ranges, which are given figure 4. the middle anisian (pelsonian) to ?fassanian (ladinian) section at seljani. drowning of the shallow-water ravni carbonate ramp to deposition of the drowning sequence of the bulog formation. sample numbers of the described samples with the age diagnostic organisms in the ravni and bulog formations and their position in the section are indicated. in addition, the clay mineralogy of the green-grey clays are indicated (sample mm 56a). g eo lo gi a c ro at ic a 190 geologia croatica 78/3 according to krystyn (1983) and chen et al. (2016), but we also took into consideration other recently published conodont age ranges (orchard, 2010; kiliç et al., 2017; plasenicia et al., 2018; smirčić et al., 2020; rigo et al., 2018; kolar-jurkovšek & jurkovšek, 2019; kiliç, 2021; karádi et al., 2022). beside the taxonomic determinations from the above mentioned papers, the nomenclature of budurov & sudar (1990) and chen et al. (2016) was also used. however, even if some biostratigraphic age ranges of some conodont species seem to be slightly inaccurate, the biostratigraphic age based on assemblage-level composition is more accurate than ages based on the stratigraphic ranges of individual conodont species. in addition, the used age ranges of the late illyrian conodont assemblages in the east bosnian – durmitor mega-unit in montenegro were recently improved by their correlation with ammonoid-bearing levels (mrdak et al., 2024a; đaković et al., 2025). the determination of ammonoids follows the classification given by tozer (1981), as well as by vörös (2003, 2018) and monnet & bucher (2005). they are stored in the geological survey of montenegro in podgorica. determination and age dating of algae and foraminiferal assemblages follows in general ott (1972a, b), bystricky (1964, 1986), bucur et al. (1994), granier & deloffre (1994), granier & grgasović (2000), bucur (1999) – for algae, and salaj et al. (1983, 1988), rettori et al. (1994) – for foraminifera. all determined conodonts, calcareous algae, and foraminifera are stored at the montanuniversität leoben. inventory numbers are the sample numbers as described in this publication. 4. results in the investigated profile, in the upper part of the shallowwater ravni formation, beds consisting of calcareous algae together with crinoid-rich layers appear, both overlain by a condensed layer of slightly siliceous red nodular limestones (the bulog formation), with deep-water fossil groups: e.g. ammonoids, conodonts, and radiolarians (fig. 4). lithoand microfacies indicate a rapid change in the depositional environment from shallow-water to deeper-water conditions. in the ravni formation at the seljani location two generations of neptunian dikes filled with red nodular limestone are preserved. the older generation of neptunian dikes, late pelsonian in age, contain red limestones with thin-shelled bivalves and some ravni limestone clasts. this microfacies indicates a much shallower deep-marine environment, i.e. deposition on a hemipelagic swell. in such neptunian dikes bešić (1949a) found a rich and well-preserved brachiopod fauna. condensed deposition prevailed until the middle/late illyrian boundary. around the middle/late illyrian boundary, neptunian dikes were formed again and the following late illyrian bulog limestone is characterized by slightly siliceous and marly nodular limestones with intercalated channelized mass-transport deposits (breccia layers), which contain thinshelled bivalve components deposited on a hemipelagic swell. above these parts with breccia layers is another condensed horizon with ammonoids appearing in the marly radiolarianrich wackestones. up-section, the red limestones become more and more siliceous and finally radiolarites deposited. 4.1. biostratigraphy and microfacies 4.1.1. ravni formation (pelsonian) in the uppermost part of the ravni formation (dedovići member – dimitrijević, 1997), layers rich in calcareous algae with some foraminifera were deposited. in addition, crinoids are common in these layers. these layers appear shortly before the drowning sequence (bulog formation). they were deposited above shallow-water limestones predominantly consisting of microbially formed components and show a more open-marine influence regarding the underlying shallow-water limestones. the following calcareous algae (fig. 5) were determined in the different samples: – sample mm 52: julpiaella subtilis (pia), oligoporella pilosa pilosa pia, oligoporella minutula (guembel), and ?teutloporella sp. – sample mm 53: macroporella cf. alpina pia, oligop­ orella pilosa pilosa, and poncetella hexaster (pia). – sample mm 54: julpiaella cf. dissocladeloidea (pia), julpiaella subtilis, macroporella cf. alpina, oligoporella pilosa pilosa, oligoporella praealpina (pia), oligo porella minutula, and poncetella hexaster. – sample mm 58: ?julpiaella sp., ?oligoporella sp., ?euteutloporella peniculiformis (ott), and algae fragments. the following foraminifera (fig. 6) were determined in the different samples: – sample mm 54: endotriadella wirzi (koehnzaninetti), meandrospira dinarica kochanskydevidé & pantić, endoteba sp., and duostomonidae. – sample mm 58: endotriadella wirzi, endoteba sp., meandrospira dinarica, and textulariaceae. the calcareous algal association as well as the foraminifera are typical of the pelsonian ravni formation. the ravni formation in its upper part is dissected by two generations of neptunian dikes (see below). some of these neptunian dikes present most probably sills (wendt, 2017), but this cannot be determined by the preserved infillings. however, the existence of sills is proven by brachiopod findings described by bešić (1949a). 4.1.2. bulog formation (late pelsonian to ?fassanian) the drowning sequence of the ravni carbonate ramp is represented by the condensed red nodular limestones of the bulog formation (sudar et al., 2023b). the approximately 8 m-thick bulog formation of the section at seljani can be subdivided into two different lithological types, a strongly condensed slightly siliceous lower part of dark red nodular limestones with an ammonoid-rich 5 – 10 cm-thick bed at its base and a more light red and slightly marly-siliceous and marly upper part, with intercalated mass-transport deposits in channels. further up-section, after the part with mass-transport deposits, another horizon with ammonoids is observed and is overlain by siliceous radiolarian wackestones. these siliceous radiolarian wackestones transition to reddish radiolarites further up-section, which are mainly covered. in this covered area it is not visible whether volcanic ash layers are intercalated between the radiolarite beds. the radiolarians are completely g eologia c roatica 191mrdak et al.: from deep-marine stratigraphic condensation to mass-transport deposition: illyrian stepwise extension recorded in a red nodular ... figure 5. dasycladalean algae from the topmost ravni formation (pelsonian). a julpiaella subtilis (pia), sample mm 52; b ?euteutloporella peniculiformis (ott), sample mm 58; c poncetella hexaster (pia), sample mm 54; d poncetella hexaster (pia), sample mm 53; e julpiaella subtilis (pia) and oligoporella minutula (guembel), sample mm 54; f poncetella hexaster (pia), sample mm 54; g oligoporella pilosa pilosa pia and oligoporella minutula (guembel), sample mm 52; h oligoporella praealpina (pia), sample mm 58. g eo lo gi a c ro at ic a 192 geologia croatica 78/3 recrystallized to quartz and cannot be extracted, as is the entire radiolarite interval. the older type of the bulog formation above the ravni formation shows the following evolution: directly above the ravni formation, the first bed of the bulog limestone contains ammonoids, broken thin-shelled bivalves (“filaments“), radiolarians, and conodonts. in sample mm 57 from this 5 – 10 cm-thick, slightly siliceous bed, a mixed late pelsonian and early illyrian conodont fauna, indicating stratigraphic condensation, is observed (fig. 4), containing: paragondolella bifurcata budurov & stefanov, paragondolella bulgarica budurov & stefanov, paragondolella hanbulogi sudar & budurov, neogondolella cornuta budurov & stefanov, paragondolella szaboi (kovács), and gladigondolella tethydis (huckriede). this stratigraphic condensation is also proven by the formation of locally appearing hardgrounds (fig. 7a). the variability of the preserved microfauna is minor and consists only of broken thin-shelled bivalves and some recrystallized radiolarians. this is also confirmed by the strong corrosion of the ammonoid shells in this bed. in most cases the shells are dissolved or strongly corroded. very often, only moulds of the ammonoids are preserved. this facies contrasts the normally known depositional characteristics for hemipelagic swells, where red nodular limestones deposited (böhm, 1992; wendt, 1973, 2017; flügel, 2004 and references therein). from the condensed bed (sample mm 57) an ammonoid fauna was collected (fig. 8a–c). due to poor preservation, only a few ammonoids from this level could be determined: balatonites sp., philippites ? sp., and proarcestes sp. indicating a pelsonian age. higher up in the section in sample mm 59 (fig. 4), neogondolella cornuta, paragondolella eotrammeri (krystyn), paragondolella praeszaboi (kovács, papšova & perri), and gladigondolella tethydis indicate an early to middle illyrian age. the microfacies characteristics of this higher, but still early/middle illyrian bulog limestone is nearly identical to the lowermost bed. only any indications for hardground formation are missing. beside the red colour, indicating an oxygenating diagenetic environment, sedimentary layering, e.g. lamination, is also absent. irregular, distributed, broken shells indicate strong bioturbation as well as the nodular fabrics. it is beyond the scope of the paper to discuss the formation of nodular limestone. the interested reader is referred to jenkyns (1971), and flügel (2004 and references therein). the younger type of the bulog limestone with intercalated oligomictic breccias (figs. 4, 7), which appear in channels (fig. 4) contains radiolarians, “filaments“, and rare volcanic grains (e.g. biotite in the residue), but is strongly recrystallized and siliceous, in some cases marly in the upper parts (fig. 7). in the lowermost part, this bulog limestone contains gladigondolella tethydis and gladigondolella-me sensu kozur & mostler, paragondolella eotrammeri, paragondolella trammeri (kozur) and neogondolella cornuta (sample mm 60) indicating the late illyrian age. higher up gladigondolella tethydis and gladigondolella-me, paragondolella eotrammeri, paragondolella excelsa (mosher), paragondolella trammeri, and neogondolella cornuta in sample mm 61 prove a late illyrian – fassanian age. in the highest part (sample mm 62) of the more strongly recrystallized and silicified bulog limestone, a similar age is proven by the presence of gladigondolella-me, neogondolella cornuta, paragondolella excelsa, and paragondolella trammeri. the age of the matrix and the reworked material could not be distinguished on the basis of the conodont faunas. above the part with the reworked material another level with ammonoids was deposited (fig. 4). figure 6. characteristic foraminifera from the topmost ravni formation (pelsonian). a entoteba sp., sample mm 58; b endotriadella wirzi (koehn-zaninetti), sample mm 58; c meandrospira dinarica kochansky-devidé & pantić, sample mm 58; d meandrospira dinarica kochansky-devidé & pantić, sample mm 54; e meandrospira dinarica kochansky-devidé & pantić, sample mm 54. g eologia c roatica 193mrdak et al.: from deep-marine stratigraphic condensation to mass-transport deposition: illyrian stepwise extension recorded in a red nodular ... figure 7. microfacies characteristics of the latest pelsonian to late illyrian bulog limestones and lithological features of the intercalated mass-transport deposits in the late illyrian. a wackestone with a few recrystallized radiolarians, a few broken filaments and some recrystallized undeterminable components beside microbial precipitation of calcite. unsoluable clayey material is rich in stylolites which overprint locally formed hardgrounds, sample mm 57, width of the photo: 1.4 cm; b radiolarian-filament wackestone, bioturbated, sample mm 59, width of the photo: 0.5 cm; c bioturbated marly radiolarian wackestone with rare “filaments“, in cases broken and one nodosariid foraminifera, sample mm 60, width of the photo: 1.4 cm; d oligomictic mass-transport deposit. the “filament“-rich clasts are in cases coated with a dark crust. the matrix consists of a marly wackestone with broken “filaments“, sample mm 61, width of the photo: 1.4 cm; e enlargement of sample mm 61 showing details of the marly matrix rich in pyrite; f component of a “filament“-rich wackestone with a coated rim in the “filament“-rich matrix. in addition, angular clasts are visible, sample mm 62; g macroscopic view of the late illyrian oligomictic breccia with nodular fabrics, hammer as scale; h reddish-grey late illyrian nodular limestone with thin breccias layers, hammer as scale. g eo lo gi a c ro at ic a 194 geologia croatica 78/3 within this level, only poorly preserved and fragmentary specimens (fig. 8d–f) could be collected, and parasturia cf. emmrichi (mojsisovics), monophyllites cf. wengensis (klipstein) and flexoptychites sp. are determined indicating a late illyrian to ?fassanian age. 4.2. neptunian dikes in the ravni formation the age of the two generations of neptunian dikes filled with red nodular limestones correspond to the evolution of the overlying bulog limestone succession. the dense network of neptunian dikes crosscut the ravni formation, the younger generation of neptunian dikes crosscut the ravni formation, the older bulog formation and the older generation of neptunian dikes, therefore in some cases mixed, conodont faunas appear in a single sample. the dense network of neptunian dikes and fractures result in an apparent brecciated texture in parts of the ravni formation. the formation of the older generation of neptunian dikes predates the condensed drowning sequence with the ammonoid-bearing dark red condensed limestones. the two generations of neptunian dikes can be distuinguished by the colour of the infilling (fig. 9) and their microfacies. the older neptunian dikes are filled with dark-red micrite, whereas the younger neptunian dikes are filled with light-red micrite sometimes containing brachiopod shells. the conodont specimens discovered show the same cai-values (fig. 11) in both generations of neptunian dikes. the age of the the formation of these neptunian dikes is constrained by the biostratigraphic age range of every species (see e.g. chen et al., 2016). within the older generation of fissure fillings (fig. 9a), crosscut by younger fissures, the following conodonts were determined (sample mm 55, fig. 4): nicoraella kockeli (tatge), gladigondolella tethydis, neogondolella cornuta, paragondolella bifurcata, paragondolella excelsa, paragondolella hanbulogi, figure 8. ammonites from the bulog formation. a–c are from the base of the older bulog limestone (late pelsonian), and d–f were collected in the younger bulog limestone. a balatonites sp. b1–4 philippites ? sp. (different views) and suture line (b4); c proarcestes sp.; d parasturia cf. emmrichi (mojsisovics); e monophyllites cf. wengensis (klipstein); f flexoptychites sp. g eologia c roatica 195mrdak et al.: from deep-marine stratigraphic condensation to mass-transport deposition: illyrian stepwise extension recorded in a red nodular ... and paragondolella trammeri. in this older generation of neptunian dikes “filament“-rich wackestones are observed with a few shallow-water grains, hardground clasts and a few recrystallized angular ravni formation clasts (sample mm 55; fig. 9b, c). in the younger light red generation of neptunian dikes (fig. 9d) also crosscutting the older generation, the following conodonts were determined (sample mm 56; fig. 4): gladigondolella budurovi kovács & kozur, gladigondolella tethydis, paragondolella bulgarica, paragondolella hanbulogi, paragondolella excelsa, paragondolella szaboi, and paragondolella trammeri. in this younger generation of neptunian dikes slightly recrystallized “filament-limestones“ with few volcanic clasts (sample mm 56) and recrystallized limestone clasts occur (fig. 9e, f). in both sets of neptunian dikes mixed conodont faunas appear. this mixed fauna indicates two different ages within one sample, namely the late pelsonian-early illyrian and the late illyrian (to fassanian). in the older neptunian dike infilling only paragondolella trammeri indicate the younger age, wheras all other conodonts belong to the older (late pelsonian – earliest illyrian) age. these are nicoraella kockeli, neogondolella cornuta, paragondolella bifurcata, and paragondolella praeszaboi, gladigondolella tethydis and figure 9. two generations of neptunian dikes in the upper shallow-water limestones of the ravni formation and their microfacies characteristics. a a late pelsonian dike filled with dark red limestone and the position of the sample, hammer as scale; b “filament“-rich wackestone with a few shallow-water grains and a few recrystallized ravni formation clasts. in addtion, hardground clasts are visible, sample mm 55, width of the photo: 1.4 cm; c enlargement of b showing recrystallized angular ravni formation clast in a “filament“-rich biomicrite, width of the photo: 0.5 cm; d overview of the upper part of the ravni formation with two generations of neptunian dikes and incorprated green-grey marly sediments used for xrd-analysis. the sample locations are indicated, hammer as scale; e slightly recrystallized “filament-limestone“ with few volcanic clasts and recrystallized limestone clasts, sample mm 56, width of the photo: 1.4 cm; f detail of a volcanic clast in the slightly recrystallized “filament-limestone“, width of the photo: 0.5 cm. g eo lo gi a c ro at ic a 196 geologia croatica 78/3 paragondolella excelsa appear most likely in the younger neptunian dike infilling as their fad is younger as late pelsonian – earliest illyrian. in contrast, the younger neptunian dike infilling contains only two older species with paragondolella bulgarica and gladigondolella budurovi. the conodont assemblage gladigondolella tethydis, paragondolella excelsa, paragondolella szaboi, and paragondolella trammeri indicates a late illyrian (to fassanian) age. in the younger fissure generation brachiopods also appear beside clasts of volcanic material and green-grey clayey sediments. in these neptunian dikes the occurrence of volcanic grains and sediments is much more common as in the overlying light red limestones. this indicates decreasing volcanic activity after the formation of the neptunian dikes. redeposition of the various breccia levels postdate the main volcanic activity and the formation of the second horst-and-graben system. a similar conclusion was reached by mrdak et al. (2024a) more to the north in the area of durmitor mt. 4.3. clay mineralogy the analysed sample mm 56a (fig. 4) was taken from green, carbonaceous, fine-grained, marly, soft sediments in a light red neptunian dike infilling of late illyrian age. lithologically, these sediments resemble incorporated volcanic ashes in these neptunian dikes. the xrd image (fig. 10) shows no sharp peaks for the clay minerals, but a broad band of scattering, resulting in weak signals. the sample consists predominantly of calcite and only traces of clay minerals of the mica group (mainly illite) including traces of mixed layer clay minerals could be determined. strong diagenetic alteration of this sediment prevents the assignment of this material to a volcanic ash origin. only the occurrence of traces of mixed layer clay minerals give a hint for a volcanic provenance. 4.4. conodont colour alteration (cai) the diagenetic overprint of the studied sedimentary succession was estimated using the conodont colour alteration index (cai) method (for details see epstein et al., 1977; rejebian et al., 1987), calibrated with other temperature sensitive methods (nöth, 1991; königshof, 1992; rantitsch et al., 2020). characteristic conodonts of the studied sections and their conodont colour alteration index (cai) values are shown in figure 11. all conodonts are from the late pelsonian to the late illyrian, that is from the two generations of neptunian dikes and the drowning sequence of the bulog group show relative homogeneous cai values of cai 1.0, which correspond to a diagenetic overprint at 50 – 90 °c (epstein et al., 1977; burnett et al., 1994). this indicates a burial of less then 2 kilometres, meaning that it would correspond to the known thicknesses of the upper triassic to palaeogene overlying sequences in the central east bosnian – durmitor mega-unit according to dimitrijević (1997). figure 10. xrd measurement and mineralogical composition of the sample mm 56a. g eologia c roatica 197mrdak et al.: from deep-marine stratigraphic condensation to mass-transport deposition: illyrian stepwise extension recorded in a red nodular ... 5. discussion 5.1. depositional environment after formation of the ravni carbonate ramp (fig. 12a) late pelsonian tectonic motions resulted in a horst-and-graben topography indicated by neptunian dikes filled with red marly mud of the same age. 5.1.1. late pelsonian neptunian dike infilling the seljani area is only mildly folded and not too many faults can be observed. therefore, it is most likely that bešić (1949a, b) collected his well-preserved and rich brachiopod faunas at least in the strike of the described section, but the ammonoids from an older level. in contrast to the infilling of the neptunian dikes the overlying drowning sequence contain no brachiopods. as stated by wendt (1973) the environment in neptunian dikes is different compared to the environment on the sea bottom. the determined brachiopod fauna by bešić (1949a) is quite similar to widespread brachiopod faunas determined in the broader western tethys realm, as in the bulog limestones around sarajevo (bittner, 1892, 1902; kittl, 1904; mt. trebević), or the northern calcareous alps (bittner, 1890). in addition, the microfacies of the older neptunian infilling (fig. 9b, c) indicate deposition on a horst at a relative shallow-water depth (position a in fig. 12e). the recrystallized ravni formation components indicate karstification, i.e. they derive from an uplifted horst above the sea-level (fig. 12e). as in the overlying bulog limestones, this microfacies with “thin-shelled“ bivalves and hardground clasts is not preserved, it can be concluded that bottom currents transported all the sediment from this elevated position into adjacent depressions. 5.1.2. late pelsonian to middle illyrian bulog limestone the first bed of the bulog limestone representing the drowning sequence of the ravni carbonate ramp (fig. 12b) is characterized by strong stratigraphic condensation as indicated by a mixed late figure 11. photos of some characteristic conodonts of the seljani section, showing all homogeneous cai-values of cai 1.0. instead of using the white background as normally obligatory to show the cai-values a black background was used in this case. photographing the conodonts with cai 1.0 on white background would result in practically poor visibility and would hamper the determination capability of the conodonts. a nicoraella kockeli (tatge), sample mm 55; b neogondolella cornuta budurov & stefanov, sample mm 55; c gladigondolella budurovi kovács & kozur, sample mm 56; d paragondolella szaboi (kovács), sample mm 56; e paragondolella trammeri (kozur), sample mm 56; f paragondolella bulgarica budurov & stefanov, sample mm 56; g paragondolella excelsa (mosher), sample mm 56; h paragondolella bifurcata budurov & stefanov, sample mm 57; i paragondolella hanbulogi sudar & budurov, sample mm 56; j paragondolella eotrammeri (krystyn), sample mm 59; k paragondolella trammeri (kozur), sample mm 61; l gladigondolella tethydis (huckriede), sample mm 56; m neogondolella cornuta budurov & stefanov, sample mm 62; n paragondolella excelsa (mosher), sample mm 62; o paragondolella trammeri (kozur), sample mm 60; p gladigondolella tethydis (huckriede), sample mm 61; q neogondolella cornuta budurov & stefanov, sample mm 62. g eo lo gi a c ro at ic a 198 geologia croatica 78/3 pelsonian to earliest illyrian conodont and ammonoid fauna (fig. 4), but with only a few, poorly preserved brachiopods. such strongly condensed red nodular limestones with mixed faunal content appear very often in the drowning sequence of the shallow-water ravni carbonate ramp (equivalent to the steinalm carbonate ramp) elsewhere in the western tethyan realm (hauer, 1884, 1888, 1892; assereto, 1971; krystyn et al., 1971). such stratigraphic condensation is quite typical for deposition of red nodular limestones on a morphological high, where currents transport the fine-grained material into adjacent basins (wendt, 2017). that is in contrast to typical sedimentologal features described for deposition on an elevated and relative shallow high (jenkyns, 1971; fürsich, 1978; wendt, 1973; böhm, 1992; flügel, 2004). the typical features for extreme condensation such as a relatively thick hardground formation, hardground clasts, appearance of phosporites, stromatolithic fe/mn-crusts etc. are missing (flügel, 2004 and references therein). in contrast, the radiolarian-rich microfacies with intense corrosion of ammonoid shells indicates deposition in relatively deep-water, that is near to the aragonite compensation depth (see flügel, 2004 for details). as the age of the basal bulog limestone bed is only slightly younger than the neptunian dike infilling below, a extreme rapid subsidence of the block can be concluded (from position a to position b in fig. 12e). stratigraphic condensation prevailed until the middle/late illyrian boundary (fig. 12c). 5.1.3. late illyrian neptunian dike infilling these neptunian dikes, which cross-cut the older bulog limestone, the ravni formation with the older neptunian dikes (fig. 12d), contain “filament-rich“ wackestones with volcanic clasts (fig. 9e, f), beside a late illyrian conodont fauna, and greenish-grey clays (fig. 9d) with traces of mixed layer clay minerals (fig. 10). while in the underlying bulog limestone no traces of volcanic activity could be recognized, we attribute the creation of the second generation of neptunian dikes to the onset of volcanic activity subsequently followed by the creation of a second horst-and-graben topography (fig. 12f). the microfacies of the younger neptunian dike infilling (fig. 9e, f) indicate formation of this calcareous mud again on a deep swell in relative shallow-water, meaning that this mud was transported from newly formed swells into the deep-water depositional environment of the footwall block. reworked clasts of the ravni formation are absent in these infillings. 5.1.4. the late illyrian to ?fassanian bulog limestone around the middle/late illyrian, the depositional environment changed as indicated by the intercalated oligomictic breccias (fig. 7g, h) in a marly-silicous matrix with broken thin-shelled bivalves (fig. 7d–f). these breccias can be compared to the younger komarani formation (sudar et al., 2023b), which was also recently described from the east bosnian – durmitor mega-unit (mrdak et al., 2024a). breccia components are coated by hardgrounds, and their microfacies characteristics (fig. 7d–f) are similar to the microfacies of younger neptunian dike infillings. in the matrix, only a few volcanic clasts appear. reworked material from the ravni formation is missing in these oligomictic breccias. while most of the components are characterized by intensive coatings, they originated from a deep swell at a relative shallow-water depth. in contrast, the more greyish marly siliceous matrix indicates deposition in a basinal environment. the basin received reworked material from the adjacent high (fig. 12f). 5.2. age of the ammonoid fauna 5.2.1. ammonites from the basal drowning sequence the determined ammonites balatonites sp., philippites ? sp., and proarcestes sp. from the lower condensed red nodular limestone contain taxa, which normally are typical for the pelsonian. it should be noted that specimens assigned to the genus balatonites show most resemblance to balatonites ottonis (buch) in being strongly ornamented, whereas the one tentatively assigned to philippites also shows a resemblance to nicomedites barbarossae (arthaber) being lateraly compressed and having a high, subtriangular whorl section. this would imply that the ammonoid fauna in this level could also be of bithynian age, since nicomedites is still unknown from the pelsonian, and some authors consider that balatonites ottonis (buch) could also indicate a bithynian age (e.g. vörös, 2003; siegel et al., 2022). however, a preserved part of the suture line in the specimen figure 8 (b4), i.e. its first lateral saddle is identical to philippites, and is compressed due to fossilization. the subtriangular whorl section is more or less a characteristic of all beyrichitidae, to which both nicomedites and philippites belong. on the other hand, the appearance of balatonites cf. ottonis (buch) in the balaton highland together with balatonites balatonicus (mojsisovics) and other pelsonian forms as reported by vörös (2003), excludes it from being used as a zonal marker. this does not contradict the proposal of siegel et al. (2022) for the germanic basin, but also raises a question of whether this fauna could also belong to the pelsonian. in conclusion, the sparse fauna from this level is considered to be pelsonian, but redeposition of a much older fauna represented by dissolved and corroded specimens cannot be excluded, although it is not likely because of the underlying shallow-water ravni formation. 5.2.2. pelsonian ammonites from bešić (1949b) bešić (1949b) also determined and described an ammonoid fauna from the seljani region, but south of the studied section presented here (at the locality of radonjića vrt and komarnički brod). what he mentioned is that the locality is situated on a hiking trail between the komarnica river and the villages of rudinice and seljani (fig. 2b). at that time, the artifical piva lake did not exist in the area, but according to his description, it can be assumed that it is in the area between the river komarnica and the village of rudinice, and it is most probably now flooded. bešić (1949b) mentioned another locality with ammonoids, also not indicated on the map, but probably situated somewhere in the vicinity of sinjac. however, he stated that these ammonoids are not found within the red bulog limestones, but in the grey, in parts dolomitized marly limestones. according to bešić (1949b) the section starts near the river (now a lake) with sandy limestones of the upper werfen formation followed by grey dolomitized massive limestones. up-section this is followed by a grey, marly limestone, belonging to what can only be assumed to be a formation not described g eologia c roatica 199mrdak et al.: from deep-marine stratigraphic condensation to mass-transport deposition: illyrian stepwise extension recorded in a red nodular ... in detail in this area. this part of the section contains the quite well-preserved ammonoid fauna described by bešić (1949b). the presence of proteusites in one and acrochordiceras genera in the other assemblage, should both indicate a pelsonian age. above this level with the ammonites, grey dolomitized (in fact recrystallized) limestones with brachiopods follow (bešić, 1949a), which derive from neptunian dikes in the upper ravni formation (dedovići member). however, this ammonoid fauna does not derive from the bulog formation or an age-equivalent limestone, i.e. the drowning sequence of the ravni carbonate ramp. this ammonoid fauna from bešić (1949b) derives from an openmarine level between the lower utrine member of the ravni formation and the upper dedovići member of the ravni formation. this stratigraphic level indicates the first deepening trend due to the opening of the neo-tethys ocean to the east and is known from the northern calcareous alps, termed there the annaberg formation (gawlick et al., 2021 and references therein). sequences analogous to the annaberg formation in the northern calcareous alps have not been previously known from the dinarides, but the existence of such an open-marine level in the ravni formation is known from the area south of sarajevo (trebević mt.) (sudar, 1986). revision of the hallstatt limestone sections in trebević mt. results in the correlation of the trebević member of the ravni formation and the annaberg formation in the northern calcareous alps (sudar et al., 2025 and references therein), deposited around the bithynian/pelsonian boundary. a similar lithology was also found in the budva unit, sensu lato, by đaković et al. (2018). 5.2.3. ammonites from the higher bulog limestone sequence in the upper part of the bulog formation, above the breccia layers, a second ammonoid-bearing level was detected. within this level, only poorly and fragmentary preserved specimens could be collected. the determined fauna with parasturia cf. emmrichi, monophyllites cf. wengensis and flexoptychites sp. can only be assigned to a late illyrian – fassanian age, since these ammonites are all long-ranging taxa. however, parasturia emmrichi is in the western tethys realm found from the aplococeras avisianum zone to the nevadites secedensis zone (manfrin et al., 2005; vörös, 2018), which makes this interval tentatively comparable with the kovčezi section ammonoids, recently published by đaković et al. (2025). also, from the sedimentological point of view, this ammonoid fauna in the seljani section appears in a comparable level above the breccias of the komarani formation as in the kovčezi section (mrdak et al., 2024a). 5.3. reconstruction of pelsonian – illyrian geodynamic evolution the uppermost shallow-marine limestones of the ravni carbonate ramp with open-marine influence represent the last sedimentary rocks deposited in an epicontinental sea (gawlick & missoni, 2019 and references therein), i.e. they represent the uppermost part of deposition in the graben shortly before the continental break-up (fig. 12a), related to the opening of the neo-tethys ocean around the pelsonian/illyrian boundary (gawlick et al., 2008; ozsvárt et al., 2012; djerić et al., 2024 and references therein). the drowning of the ravni carbonate ramp (and the equivalent steinalm carbonate ramp) is time-equivalent everywhere in the western tethys realm (schlager & schöllnberger, 1974; kovács et al., 2010, 2014; sudar et al., 2013; gawlick et al., 2021; karádi et al., 2022; mrdak et al., 2024a). this drowning is characterized by the overregional demise of shallow-water carbonate production and formation of the break-up unconformity, in the form of horst-and-graben structures (fig. 12). in the frame of the formation of the late pelsonian horst-and-graben structure due to extension, some horsts uplifted and karstified while others sink into a deeperwater position (sudar et al., 2013). in such cases it can be expected that the subsidence of such horsts is rather high, but this was never proven or documented. in seljani, the late pelsonian neptunian dike infillings are characterized by a “filament-rich“ microfacies typical of relatively shallow deepswells (most probably some few 10s of metres water depth; böhm, 1992; wendt, 2017) where bottom currents transport the fine-grained material into adjacent basins. in contrast, the drowning sequence, presented by the first condensed layer with ammonoids of the bulog formation (fig. 12b), also of late pelsonian age, is characterized by a deep-water microfacies (most probably more than 100 m water depth; gawlick et al., 2012). this proves a very rapid subsidence during the short time span of the late pelsonian (fig. 12e). during early/middle illyrian times condensed deposition prevailed (fig. 12c). around the middle/late illyrian boundary a second pulse of tectonics create a second generation of neptunian dikes (fig. 12d), which crosscut the older generation. a new horst-andgraben system formed and the former horsts were flooded and condensed red nodular limestones with hardgrounds deposited. reworked material from these flooded horsts was transported gravitationally into the deeper environments forming masstransport deposits. whereas near to the escarpments thick breccia bodies were deposited (compare sudar et al., 2023b; mrdak et al., 2024a). in a more distal position, breccias of reduced thickness were desposited in channels (fig. 12f). upsection, the amount of intercalated breccias decreased and a second condensed layer with ammonoids was deposited. the whole bulog limestone succession is siliceous and rich in recrystallized radiolarians. above the second ammonoidbearing horizon, the bulog limestone is characterized by an increasing amount of silica and finally overlain by reddish radiolarites of ladinian age. the water depth of the late anisian basin can be estimated only by the sedimentological (microfacies) characteristics and the overlying sedimentary rocks. as already stated by bešić (1949b) the bulog limestone succession and the overlying basinal sedimentary rocks are overlain by limestones and dolomites of the wetterstein carbonate platform with a variable thickness of 50 to 100 metres. mirković (1980) assumed a thickness of up to 200 m for the whole ladinian in the wider region, referring to the entire sequence from the radiolarites to the wetterstein carbonate platform, during that time seen as part of the ladinian. it can be concluded, that the lower thicknesses of the wetterstein carbonate platform sedimentary rocks reflect deposition on top of the shallower g eo lo gi a c ro at ic a 200 geologia croatica 78/3 swells, whereas the greater thickness reflects deposition in a basinal position. together with the decompacted thicknesses of the late anisian to ladinian basinal sedimentary rocks (≈30 m-thick), the water depth of the deep swells hardly exceed 200 metres. a similar conclusion of a water depth of 200 (-300) metres for similar basins was reached for the late anisian – ladinian basinal deposits in the high karst unit by gawlick et al. (2012). above an unconformity, the carbonates of the wetterstein carbonate platform (in contrast to mirković, 1980) were overlain by limestones of the dachstein carbonate figure 12. reconstruction of the depositional environment and geodynamic evolution in the timespan middle pelsonian to the late illyrian (?fassanian) and the position of the seljani studied section. a deposition of the middle pelsonian shallow-water limestone of the uppermost ravni formation with dasycladalean-rich beds containing crinoids in its uppermost part indicating an increasing open-marine influence; b late pelsonian to earliest illyrian drowning sequence of the ravni carbonate ramp. the formation of the neptunian dikes filled with late pelsonian bulog limestone predates the deposition of the siliceous condensed ammonid-bearing red limestone, indicating tectonic motions; c early – middle illyrian deposition of relatively condensed dark-red siliceous bulog limestones during a period of relative tectonic quiesence; d late illyrian period of rapid deepening and tectonic motions. a younger generation of neptunian dikes crosscut the older lithologies, subsequently followed by deposition of red nodular limestones with intercalated breccia channels and volcanic clasts. the topmost part of the bulog limestone also contains an ammonoid-bearing horizon; e recontruction of the late pelsonian formation of a horst-and-graben system. neptunian dikes were formed during this phase of extension. parts of the dismembered ravni carbonate ramp were uplifted and karstified while other parts underwent rapid subsidence (a) and took a deep swell position (b) in a graben during late pelsonian times; f around the middle/late illyrian boundary, a second phase of extension created a second horst-and-graben topography, with the formation of neptunian dikes. the elevated horst flooded. from the newly formed escarpments mass-transport deposits accumulated in the grabens and half-grabens. g eologia c roatica 201mrdak et al.: from deep-marine stratigraphic condensation to mass-transport deposition: illyrian stepwise extension recorded in a red nodular ... platform. this unconformity is marked by bauxite lenses (mirković, 1980), which most probably mark the middle – late carnian stratigraphic gap (mrdak et al., 2023), before the onset of the dachstein carbonate platform, with a thickness of up to 700 m (mirković, 1980). bešić (1949b) contributed by the discovery of megalodon sp., an open lagoonal depositional environment indicator, during the norian in the region near the seljani section. this middle – late triassic sedimentary sequence also disproves the existence of a deep-water intraplatform basin (bosnian trough/basin) between the east bosnian – durmitor mega-unit and the pre-karst unit. 6. conclusion the bulog limestone evolution and the two generations of neptunian dike infillings in the ravni formation, reflect two phases of tectonic extension and a stepwise deepening of the depositional environment. the first event in the late pelsonian is related to the onset of the opening of the neo-tethys and a rapid subsidence of some blocks from shallow-water depths to a relative deep-water environment of at least 100 m water depth during late pelsonian times is documented here for the first time. the second deepening event starting around the middle/late illyrian boundary, and can be correlated with the onset of intense volcanic activity. a second generation of neptunian dikes and a second horst-and-graben structure was created. the late anisian to ladinian depositional history is elsewhere in the east bosnian – durmitor mega-unit and adjacent areas characterized by the deposition of deep-water sedimentary rocks and cannot be used for any palaeogeographic reconstuctions of the existence of deep-water intraplatform basins. during this time span practically no shallow-water carbonate production existed, and in the entire dinarides from the open (distal) shelf (hallstatt shelf) to the east to the budva unit to the west, specific deep-water sedimentary rocks were deposited. the gordian knot of the controversial discussion about the tectonic position of the tectonic outlier with the studied section at seljani and a possible affiliation to an existing long-lasting intraplatform basin (kuči unit, zone bosniaque/zone serbe in parts) is now open. acknowledment published in the frame of the igcp 710 project “western tethys meets eastern tethys“. field work was partly performed in the frame of the oead wtz project me 08/2020. m.m. thanks the ceepus network ciii network rs 0038 (coordinator k. šarić, belgrade) for financial support during the stay at the montanuniversitaet leoben/austria. n. djerić acknowledges the contribution to the ministry of science, technological development and innovation of the republic of serbia (contract no. 451-03-136/2025-03/200126) and science fund of the republic of serbia (grant no. tf c1389-yf/ project no. 7461). thanks to the department of applied geosciences and geophysics, chair of energy geosciences for the use of the laboratory equipment. thanks to f. seidl (leoben), who measured the xrd-sample. thanks to a. schellich and b. mang (leoben) for logistic support during the ceepus stays of m.m. in leoben. f. melcher (chair of geology and economic geology, leoben) for permitting the use of the digital-microscope for conodont photographs. thanks to the colleagues of the geological survey of montenegro (podgorica) for discussions about the geology of montenegro. careful reviews of tea kolarjurkovšek (ljubljana) and anonymous reviewer are gratefully acknowledged. we kindly thank tonći grgasović (zagreb) for a reference suggestion and tea fluksi (zagreb) for the professional editorial handling. references assereto, r. (1971): die binodosus-zone. ein jahrhundert wissenschaftlicher gegensätze.–sitzungsberichte der österreich akademie der wissenschaften: mathematisch-naturwissenschaftliche classe, abt. i. 179, 25–53. aubouin, j., blanchet, r., cadet, j.p., celet, p., charvet, j., chorowicz, j., cousin, m. & rampnoux, j.p. (1970): essai sur la géologie des dinarides.– bulletin de la société géologique de france, 7/12, 1060–1095. balini, m., lucas, s.g., jenks, j.f. & spielmann, j.a. (2010): triassic ammonoid biostratigraphy: an overview.– geological society special publications, 334, 221–262. https://doi.org/10.1144/sp334.10 bešić, z. (1936): prethodna saopštenja o geološkoj građi crne gore [comu­ nications préliminares sur la géologie du monténégro – in serbian, french summary].– geološki anali balkanskoga poluostrva, 13, 1–6. bešić, z. (1949a): trijaska brahiopodska fauna iz sela seljani u pivi (crna gora) [la fauna a brahiopodes du trias aux environs su village seljani dans la piva (montenegro), 2 plates – in serbian, french summary].– geološki anali balkanskoga poluostrva, 17, 105–122. bešić, z. (1949b): cefalopodski krečnjaci iz seljana u pivi, njihova fauna i odnos prema brahiopodskim krečnjacima istoga mesta [les calcaires à cephalopodes de seljani à piva, leur faune et le rapport entre ceux – ci et les calcaires à brachiopodes du meme endroit – in serbian, french summary].– glasnik prirodnjačkog muzeja srpske zemlje, a/2, 131–148. bittner, a. (1890): die brachiopoden der alpinen trias.– abhandlungen der geologischen reichsanstalt, 14, 1–325. bittner, a. (1892): ein neuer fundort von brachiopoden bei sarajevo.– verhandlungen der kaiserlich-königlichen geologischen reichsanstalt wien, 14, 349–350. bittner, a. (1902): brachiopoden und lamellibranchiaten aus der trias von bosnien, dalmatien und venetien.– jahrbuch der geologischen reichsanstalt wien, 52/3–4, 495–643. blanchet, r., cadet, j.-p. & charvet, j. (1970): sur l’existence d’unités intermédiaires entre la zone du haut-karst et l’unité du flysch bosniaque en yougoslavie: la sous-zone prékarstique.– bulletin de la société géologique de france, 7/12, 227–236. böhm, f. (1992): mikrofazies und ablagerungsmilieu des lias und dogger der nordöstlichen kalkalpen.– erlanger geologische abhandlungen, 121, 55–217. bucur, i.i. (1999): stratigraphic significance of some skeletal algae (dasycladales, caulerpales) of the phanerozoic.– in: farinacci, a. & lord, a.r. (eds.): depositional episods and bioevents.– palaeopelagos special publication, 2, 53–104. bucur, i.i., strutinski, c. & pop-strătilă, d. (1994): middle triassic carbonate deposits and calcareous algae from the sasca zone (southern carpathians, romania).– facies, 30, 85–100. https://doi.org/10.1007/ bf02536891 budurov, k.j. & sudar, m.n. (1990): late triassic conodont stratigraphy. in: ziegler, w. (ed.): papers on conodonts and ordovician to triassic conodont stratigraphy. contribution iv.– courier forschungsinstitut senckenberg, 118, 203–239. https://doi.org/10.52321/ geolbalc.25.3-4.97 burnett, r.d., higgins, a.c. & austin, r.l. (1994): carboniferous-devonian conodont cai in england, wales and scotland. the pattern and its interpretation: a synoptic review.– courier forschungsinstitut senckenberg, 168, 267–280. https://doi.org/10.1144/sp334.10 g eo lo gi a c ro at ic a 202 geologia croatica 78/3 bystricky, j. (1964): slovensky kras. stratigrafia a dasycladaceae mezozoika slovenskeho krasu.– ustredny ustav geologicky, bratislava, 204 pp. bystricky, j. (1986): stratigraphic ranging and zonation of dasycladal algae in the west carpathians mts., triassic.– mineralia slovaca, 18, 289– 321. cadet, j.-p. (1976): contribution à l’étude géologique des dinarides: les confins de la bosnie herzégovine et du monténégro.– thèse de doctorat ès sciences, univ. orléans, 450 p. charvet, j. (1978): essai sur un orogène alpin. géologie des dinarides au niveau de la transversale de sarajevo (yougoslavie).– these sciences, université de lille, société géologique du nord. publication 2, 554 p. chаrvеt, ј. (1980): dévelopment de l’orogène dinarique d’après l’étude du secteur transversal de sarajevo – yougoslavie.– revue de géologie dynamique et de géographie physique, france, 22/1, 3–13. chаrvеt, ј., fisсhеr, r. & каuffmаnn, g. (1974): рréсisiоns sur lе тriаs pélagique des dinarides аu nord de sаrајеvо.– annales de la societe géologique du nord, 44/3, 109–116. chen, y., krystyn, l., orchard, m.j., lai, x.l. & richoz, s. (2016): a review of the evolution, biostratigraphy, provincialism and diversity of middle and late triassic conodonts.– papers in palaeontology, 2: 235–263. https://doi.org/10.1002/spp2.1038 dercourt, j., ricou, l.e. & vrielynck, b. (1993): atlas tethys palaeoenvironmental maps and explanatory notes.– gauthier-villars, 307 p. dimitrijević, m.d. (1997): geology of yugoslavia.– geological institute gemini, special publications, 187 p. djerić, n., gawlick, h.j. & sudar, m. (2024): the jurassic ophiolitic mélanges in serbia – a review and new insights.– in: dilek, y., festa, a. & barbero, e. (eds.): significance of ophiolites, mélanges and blueschist assemblages in probing the crustal anatomy and geodynamic evolution of orogenic belts. journal of the geological society london, 181, 23 p. https://doi.org/10.1144/jgs2023-165 đaković, m., gawlick, h.-j., čađenović, d., missoni, s., milić, m. & krystyn, l. (2018): bithynian cherty limestones of the rosni virovi locality, budva zone (southern montenegro).– in: neubauer, f., brendel, u. & friedl, g. (eds.): xxi international congress of the carpathian balkan geological association (cbga), 10.–13. sept. 2018: advances of geology in southeast europaean mountain belts, geologica balcanica, 64. bulgarian academy of sciences, sofia, 64–64. đaković, m., mrdak, m. & gawlick, h.‐j. (2025): pelsonian and illyrian (anisian, middle triassic) ammonoid faunas from the bulog group of kovčezi, durmitor mountain, dinarides (northern montenegro).– austrian journal of earth sciences. 118, 1–40. https://doi.org/10.17738/ ajes.2025.0001 epstein, a.g., epstein, j.b. & harris, l.d. (1977): conodont color alteration index to organic metamorphism.– geological survey professional paper, 995, 1–27. https://doi.org/10.3133/pp995 fisсhеr, r. & јасоbshаgеn. v. (1976): zur biostratigraphischen gliederung südjugoslawischer hallstätter kalke.– neues јahrbuch für geologie und paläontologie, abhandlungen, 15/1, 31–57. flügel, e. (2004): microfacies of carbonate rocks. analysis, interpretation and application.– springer, 976 p. fürsich, f.t. (1978): the influence of faunal condensation and mixing on the preservation of fossil benthic communities.– lethaia. 11, 243–250. http:// doi.org/10.1111/j.1502-3931.1978.tb01231.x gawlick, h.-j. & missoni, s. (2019): middle-late jurassic sedimentary mélange formation related to ophiolite obduction in the alpine-carpathian-dinaridic mountain range.– gondwana research, 74, 144–172. https://doi.org/10.1016/j.gr.2019.03.003 gawlick, h.j., krystyn, l. & lein, r. (1994): conodont colour alteration indices: palaeotemperatures and metamorphism in the northern calcareous alps – a general view.– geologische rundschau, 83, 660–664. https://doi.org/10.1007/bf01083235 gawlick, h.j., frisch, w., hoxha, l., dumitrica, p., krystyn, l., lein, r., missoni, s. & schlagintweit, f. (2008): mirdita zone ophiolites and associated sediments in albania reveal neotethys ocean origin.– international journal of earth sciences, 97, 865–881. https://doi.org/10.1007/s00531-007-0193-z gawlick, h.-j., goričan, s., missoni, s. & lein, r. (2012): late anisian platform drowning and radiolarite deposition as a consequence of the opening of the neotethys ocean (high karst nappe, montenegro).– bulletin de la société géologique de france, 183, 349–358. https://doi. org/10.2113/ gssgfbull.183.4.349 gawlick, h.-j., missoni, s., suzuki, h., sudar, m., lein, r. & jovanović, d. (2016): triassic radiolarite and carbonate components from the jurassic ophiolitic mélange (dinaridic ophiolite belt).– swiss journal of geosciences, 109/3, 473–494. https://doi.org/10.1007/s00015016-0232-5 gawlick, h.-j., sudar, m.n., missoni, s., suzuki, h., lein, r. & jovanović, d. (2017a): triassic-jurassic geodynamic history of the dinaridic ophiolite belt (inner dinarides, sw serbia): field trip guide, 13th workshop on alpine geological studies (zlatibor).– journal of alpine geology, 55, 167 p. gawlick, h.j., missoni, s., sudar, m.n., goričan, š., lein, r., stanzel, a.i. & jovanović, d. (2017b): open-marine hallstatt limestones reworked in the jurassic zlatar mélange (sw serbia): a contribution to understanding the orogenic evolution of the inner dinarides.– facies, 63, 29. http://doi.org/10.1007/s10347-017-0510-3 gawlick, h.-j., missoni, s., sudar, m.n., suzuki, h., méres š., lein, r. & jovanović, d. (2018): the jurassic hallstatt mélange of the inner dinarides (sw serbia): implications for triassic-jurassic geodynamic and palaeogeographic reconstructions of the western tethyan realm.– neues јahrbuch für geologie und paläontologie: abhandlungen, 288/1, 1–47. http://dx.doi.org/10.1127/njgpa/2018/0721 gawlick, h.j., lein, r. & bucur, i.i. (2021): precursor extension to final neo-tethys break-up: flooding events and their significance for the correlation of shallow-water and deep-marine organisms (anisian, eastern alps, austria).– international journal of earth sciences, 110, 419–446. http://doi.org/10.1007/s00531-020-01959-w gawlick, h.-j., sudar, m., jovanović, d., lein, r., missoni, s.† & bucur, i.i. (2023): from shallow-water carbonate ramp to hemipelagic deep-marine carbonate deposition: part 1. general characteristics, microfacies and depositional history of the middle to late anisian bulog sedimentary succession in the inner dinarides (sw serbia).– geološki anali balkanskoga poluostrva, 84/2, 1–39. https://doi.org/10.2298/ gabp230329006g goričan, š., đaković, m., baumgartner, p.o., gawlick, h.-j., cifer t., djerić, n., horvat, a., kocjančič, a., kukoč, d. & mrdak, m. (2022): mesozoic basins on the adriatic continental margin – a cross-section through the dinarides in montenegro.– folia biologica et geologica, 63/2, 85–150. http://doi.org/10.3986/f bg0099 granier, b. & deloffre, r. (1994): inventaire critique deas algues dasycladales fossils iii partie – les agues dasycladales du permien et du trias.– revue de paléobiologie, 14, 49–84. granier, b. & grgasović, t: (2000): les algues dasycladales du permien et du trias. nouvelle tentative d´inventaire bibliographique, géographique et stratigraphique.– geologica croatica, 53, 1–197. hauer, f.v. (1884): cephalopoden der unteren trias vom han bulog an der miliaka oso von sarajevo.– verhandlungen der kaiserlich-königlichen geologischen reichsanstalt, 12, 217–219. hauer, f.v. (1888): die cephalopoden des bosnischen muschelkalkes von han bulog bei sarajevo.– denkschriften der kaiserlichen akademie der wissenschaften, mathematisch-naturwissenschaftliche klasse, 54/1, 1–50. hauer, f.v. (1892): beiträge zur kenntniss der cephalopoden aus der trias von bosnien. i. neue funde aus dem muschelkalk von han bulog bei sarajevo.– denkschriften der kaiserlichen akademie der wissenschaften, mathematisch-naturwissenschaftliche klasse, 59, 251–296. hrvatović, h. (2006): geological guidebook through bosnia and herzegovina. monograph of herald geological.– geological survey of bosnia and herzegovina, sarajevo, 25, 163 p. g eologia c roatica 203mrdak et al.: from deep-marine stratigraphic condensation to mass-transport deposition: illyrian stepwise extension recorded in a red nodular ... jenks, j.f., monnet, c., balini, m., brayard, a. & meier, m. (2015): biostratigraphy of triassic ammonoids. in: klug, c., korn, d., de baets, k., kruta, i. & mapes, r.h. (eds.): ammonoid paleobiology: from macroevolution to paleogeography.– springer, topics in geobiology, 44, 329–388. https://doi.org/10.1007/978-94-017-9633-0 jenkyns, h.c. (1971): the genesis of condensed sequences in the tethyan jurassic.– lethaia, 4, 327–352. http://doi.org/10.1111/j.1502-3931.1971. tb01928.x jovanović, r. (1998): osnovne karakteristike donjotrijaskih kontinentalnih crvenih slojeva zapadne srbije i njihova analiza i sinteza [basic character­ istic of lower triassic continental red beds of western serbia – in serbian and english].– geološki anali balkanskoga poluostrva. 62, 305–324. karádi, v., budai, t., haas, j., vörös, a., piros, o., dunkl, i. & tóth, e. (2022): change from shallow to deep-water environment on an isolated carbonate platform in the middle triassic of the transdanubian range (hungary).– palaeogeography, palaeoclimatology, palaeoecology, 587, 16. https://doi.org/10.1016/j.palaeo.2021.110793 kiliç, a.m. (2021): anisian (middle triassic) conodonts of the kocaeli triassic, western turkey.– journal of earth science, 32/1, 616–632. https://doi. org/10.1007/s12583-020-1384-9 kiliç, a.m., plasencia, p., guex, j. & hirsch, f. (2017): chapter seven – challenging darwin: evolution of triassic conodonts and their struggle for life in a changing world.– in: montenari, m. (ed.): stratigraphy and timescales. academic press, 2, 333–389. https://doi.org/10.1016/ bs.sats.2017.08.003 kittl, e. (1904): geologie der umgebung von sarajevo.– jahrbuch der kaiserlich-königlichen geologischen reichsanstalt, 53, 515–748. kolar-jurkovšek, t. & jurkovšek, b. (2019): konodonti slovenije (conodonts of slovenia).– geološki zavod slovenije, ljubljana, 259 p. kostaki, g., gawlick, h.-j., missoni, s., kilias, a. & katrivanos, e. (2024): new stratigraphic and paleontological data from carbonates related to the vourinos–pindos ophiolite emplacement: implications for the provenance of the ophiolites (hellenides).– journal of the geological society london, 181/2, 127. https://doi.org/10.1144/jgs2023-127 kovács, s., sudar, m., karamata, s., haas, j., péró, cs., gradinaru, e., gawlick, h.-j., gaetani, m., mello, j., polák, m., aljinović, d., ogorelec, b., kolar-jurkovšek, t., jurkovšek, b. & buser, s. (2010): triassic environments in the circumpannonian region related to the initial neotethyan rifting stage.– in: vozár, j., ebner, f., vozárova, a., haas, j., kovács, s., sudar, m., bielik, m. & péró, cs. (eds.): variscan and alpine terranes of the circum-pannonian region. slovak academy of sciences, geological institute, 87–156. kovács, s., sudar, m., karamata, s., haas, j., péró, cs., gradinaru, e., gawlick, h.-j., gaetani, m., mello, j., polák, m., aljinović, d., ogorelec, b., kolar-jurkovšek, t., jurkovšek, b. & buser, s. (2014): triassic environments in the circum-pannonian region related to the initial neotethyan rifting stage.– in: vozár, j., ebner, f., vozárova, a., haas, j., kovács, s., sudar, m., bielik, m. & péró, cs. (eds.): variscan and alpine terranes of the circum-pannonian region, 2nd edition, dvd version. geological institute sas, bratislava, 87–158. kozur, h. (2003): integrated ammonoid, conodont and radiolarian zonation of the triassic.– hallesches jahrbuch für geowissenschaften, b25, 49–79. königshof, p. (1992): der farbänderungsindex von conodonten (cai) in paläozoischen gesteinen (mitteldevon bis unterkarbon) des rheinischen schiefergebirges. eine ergänzung zur vitrinitreflexion.– courier forschungsinstitut senckenberg, 146, 1–115. кrystyn, l. (1983): das epidaurus profi1 (griесhеnlаnd) – еin веitrаg zur соnodonten-standardzoniernung des tethyalen ladin und unterkarn.– schriftenreihe der еrdwissenschaftlichen коmmissionen, 5, 231–258. krystyn, l., schäffer, g. & schlager, w. (1971): über die fossillagerstätten in den triadischen hallstätter kalken der ostalpen.– neues jahrbuch für geologie und paläontologie, abhandlungen, 137, 284–304. manfrin, s., mietto, p. & preto, n. (2005): ammonoid biostratigraphy of the middle triassic latemar platform (dolomite, italy) and its correlation with nevada and canada.– geobios, 38, 477–504. https://doi. org/10.1016/j.geobios.2004.01.005 martelli, a. (1904): cefalopodi triasici di boljevici presso vir nel montenegro.– palaentographia italica, 10, 75–140. martelli, a. (1906): contributo al muschelkalk superiore del montenegro.– palaeontographia italica, 23, 97–154. mietto, p., manfrin, s., pretto, n., gianolla, p., krystyn, l. & roghi, g. (2003): proposal of the global stratigraphic section and point (gssp) for the base of the ladinian stage (middle triassic) – gssp at the base of the avisianum subzone (fad of aplococeras avisianum) in the bagolino section (southern alps, ne italy).– albertiana, 28, 26–34. mirković, m. (1980): osnovna geološka karta sfrj 1: 100 000. tumač za list gacko k 34-26 [basic geological map of sfry 1: 100 000, gacko sheet k 34­26 – in serbian, english and russian summary].– savezni geološki zavod beograd. mirković, m. (1983): geology and tectonics of durmitor, piva and volujak mountains [geološki sastav i tektonika planina durmitora, pivske plan­ ine i volujaka – in serbian, english summary].– posebna izdanja geološkog glasnika, 5, 1–116. mirković, m., pajović, m. & kalezić, m. (1979): osnovna geološka karta sfrj 1: 100 000, list gacko k 34-26 [basic geological map of sfry 1: 100 000, gacko sheet k 34­26 – in serbian].– savezni geološki zavod beograd. missoni, s. & gawlick, h-j. (2012): jurassic mountain building and mesozoic-cenozoic geodynamic evolution of the northern calcareous alps as proven in the berchtesgaden alps (germany). facies, 57, 137–186. https://doi.org/10.1007/s10347-010-0225-1 monnet, c. & bucher, h. (2005): new middle and late anisian (middle triassic) ammonoid faunas from northwestern nevada (usa): taxonomy and biochronology.– fossils and strata, 52, 1–121. https://doi. org/10.18261/9781405163651-2005-01 mrdak, m., wegerer, e., sudar, m., djerić, n., đaković, m. & gawlick, h.-j. (2023): demise of the wetterstein carbonate platform and onset of the dachstein carbonate platform recorded in deep-water successions of the east bosnian-durmitor meaga-unit (pliješevina, northern montenegro, dinarides).– geologica carpathica, 74/6, 443–458. https://doi.org/10.31577/geolcarp.2023.26 mrdak, m., đaković, m., gawlick, h.j., djerić, n., bucur, i.i., sudar, m., milić, m. & čađenović, d. (2024a): middle triassic stepwise deepening and stratigraphic condensation associated with illyrian volcanism in the durmitor mountain, montenegro.– facies, 70/3, 1–31. https://doi.org/10.1007/s10347-024-00683-0 mrdak, m., wegerer, e. & gawlick, h.-j. (2024b): enigmatic traces of volcanisms in the rhaetian of a far-travelled late triassic hallstatt nappe in northern montenegro.– in: pangeo-deuqua workshop-austria, salzburg, book of abstracts. faculty of natural and life sciences, salzburg. 122 p. nöth, s. (1991): die conodontendiagenese als inkohlungsparameter und ein vergleich unterschiedlich sensitiver diageneseindikatoren am beispiel von triassedimenten nordund mitteldeutschlands.– bochumer geologische und geotechnische arbeiten, 37/3, 1–169. orchard, m. (2010): triassic conodonts and their role in stage boundary definition.– geological society london, special publications, 334, 139– 161. https://doi. org/10.1144/sp334.7 ott, e. (1972a): zur kalkalgen-stratigraphie der alpinen trias.– mitteilungen gesellschaft geologie bergbaustudenten österreich, 21, 455-464. ott, e. (1972b): die kalkalgen-chronologie der alpinen mitteltrias in angleichung an die ammoniten-chronologie.– neues jahrbuch geologie paläontologie abhandlungen, 141, 81–115. ozsvárt, p., dosztály, l., migiros, g., tselepidis, v. & kovács, s. (2012): new radiolarian biostratigraphic age constraints on middle triassic basalts andradiolarites from the inner hellenides (northern pindos and othris mountains, northern greece) and their implications for the geodynamic evolution of the early mesozoic tethys.– international journal of earth sciences, 101, 1487–1501. https://doi.org/10.1007/s00531-0100628-9. https://doi.org/10.1016/j.geobios.2004.01.005 https://doi.org/10.1016/j.geobios.2004.01.005 https://doi.org/10.18261/9781405163651-2005-01 https://doi.org/10.18261/9781405163651-2005-01 g eo lo gi a c ro at ic a 204 geologia croatica 78/3 pantić, s. (1967): trijaski mikrofosili severozapadne crne gore [triassic microfossils of northwestern montenegro – in serbian, english summary].– geološki glasnik knj. v, 89–97. plasencia, p., kiliç, a.m., baud, a., sudar, m. & hirsch, f. (2018): the evolutionary trend of platform denticulation in middle triassic acuminate gondolelloidae (conodonta).– turkish journal of zoology, 42, 187–197. https://doi.org/10.3906/zoo-1708-20 radivojević, d. (2023): evolution of the southeastern part of the panno nian basin and its implications.– geološki anali balkanskoga poluostrva, 84/2, 133–145. https://doi.org/10.2298/gabp230624008r rampnoux, j.p. (1974): contribution à l`etude géologique des dinarides: un secteur de la serbie méridionale et du monténégro oriental (yougoslavie).– memorie de la société géologique de france, 119, 1–99. rantitsch, g., bryda, g. & gawlick, h.j. (2020): conodont thermometry by raman spectroscopy on carbonaceous material: a case study from the northern calcareous alps (mürzalpen nappe, eastern alps).– austrian journal of earth sciences, 113/1–2, 201–210. https://doi. org/10.17738/ ajes.2020.0012 rejebian, v.a., harris, a.g. & huebner, j.s. (1987): conodont color and textural alteration: an index to regional metamorphism, contact metamorphism, and hydrothermal alteration.– geological society of america bulletin, 99/4, 471–479. https://doi.org/10.1130/0016-7606(1987)99<471:ccataa>2.0.co;2 rettori, r., angiolini, l. & muttoni, g. (1994): lower and middle triassic foraminifera from the eros limestone, hydra island, greece.– journal of micropalentology, 13, 25–46. https://doi.org/10.1144/jm.13.1.25 rigo, m., mazza, m., karádi, v. & nicora, a. (2018): new upper triassic conodont biozonation of the tethyan realm.– in: tanner, l.h. (ed.): the late triassic world: earth in a time of transition. springer, 189–235. https://doi.org/10.1007/978-3-319-68009-5_6 salaj, j., borza, k. & samuel, o. (1983): triassic foraminifers of the west carpathians.– geologicky ustav dionyza stura, bratislava, 213 p. salaj, j., trifonova, e. & gheorghian, d. (1988): a biostratigraphic zonation based on benthic foraminifera in the triassic deposits of the carpatho-balkans.– revue de paléobiology, vol spéc 2, 153–159. salopek, m. (1911): über die cephalopodenfaunen der mittleren trias von süddalmatien und montenegro [in croatian].– abhandlungen der kaiserlich-könglichen geologischen reichstanstalt, 16/3, 1–44. schlager, w. & schöllnberger, w. (1974): das prinzip stratigraphischer wenden in der schichtfolge der nördlichen kalkalpen.– mitteilungen der geologischen gesellschaft, 66–67, 165–193. schmid, s.m., bernoulli, d., fügenschuh, b., maţenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine-carpathian-dinaride-orogenic system: correlation and evolution of tectonic units.– swiss journal of geosciences, 101, 139– 183. https://doi. org/10.1007/s00015-008-1247-3 schmid, s.m., fügenschuh, b., kounov, a., maţenco, l., nievergelt, p., oberhansli, r., pleuger, j., schefer, s., schuster, r., tomljenović, b., ustaszewski, k. & van hinsbergen, d.j.j. (2020): tectonic units of the alpine collision zone between eastern alps and western turkey.– gondwana research, 78, 308–374. https://doi.org/10.1016/j. gr.2019.07.005 siegel, f., wiese, f. & klug, c. (2022): middle anisian (bithynian to illyrian?, middle triassic) ammonoidea from rüdersdorf (brandenburg, germany) with a revision of beneckeia mojsisovics, 1882 and notes on migratory pathways.– bulletin of geosciences, 97/3, 319–361. https://doi. org/10.3140/bull.geosci.1850 smirčić, d., aljinović, d., barudžija, u. & kolar-jurkovšek, t. (2020): middle triassic syntectonic sedimentation and volcanic influence in the central part of the external dinarides, croatia (velebit mts).– geological quarterly, 64/1, 220–239. https://doi.org/10.7306/gq.1528 sudar, m. (1986): mikrofosili i biostratigrafija trijasa unutrašnjih dinarida jugoslavije između gučeva i ljubišnje [triassic microfossils and biostra­ tigraphy of the inner dinarides between gučevo and ljubišnja mts. – in serbian, english summary].– geološki anali balkanskoga poluostrva, 50, 151–394. sudar, m.n. & gawlick, h.-j. (2018): emendation of the grivska formation in the type area (dinaridic ophiolite belt, sw serbia).– geološki anali balkanskoga poluostrva, 79 /1, 1–19. sudar, m.n., gawlick, h.-j., lein, r., missoni, s., kovács, s. & jovanović, d. (2013): depositional environment, age and facies of the middle triassic bulog and rid formations in the inner dinarides (zlatibor mountain, sw serbia): evidence for the anisian break-up of the neotethys ocean.– neues jahrbuch für geologie und paläontologie, 269, 291– 320. http://doi.org/10.1127/0077-7749/2013/0352 sudar, m., gawlick, h.j., bucur, i.i., jovanović, d., missoni, s.† & lein, l. (2023a): from shallow-water carbonate ramp to hemipelagic deep-marine carbonate deposition: part 2. sirogojno (klisura quarry) – the reference section of the middle to late anisian bulog sedimentary succession in the inner dinarides (sw serbia).– geološki anali balkanskoga poluostrva, 84/2, 41–70. https://doi.org/10.2298/gabp230403007s sudar, m., gawlick, h.j., bucur, i.i., jovanović, d., missoni, s.† & lein, l. (2023b): from shallow-water carbonate ramp to hemipelagic deep-marine carbonate deposition: part 3. lithostratigraphy and formations of the middle to late anisian bulog sedimentary successions (bulog group) in the dinarides (bosnia and herzegovina, serbia, montenegro).– geološki anali balkanskoga poluostrva, 84/2, 71–106. https://doi. org/10.2298/gabp231117011s sudar, m., gawlick, h.-j. & skopljak, f. (2025): the bulog formation in the type area (sarajevo) and related middle and late triassic open-marine sedimentary successions in the dinarides of bosnia and herzegovina.– geološki anali balkanskoga poluostrva, 86/1, 1–67. https://doi. org/10.2298/gabp241216002s suess, e. (1888): das antlitz der erde. ii.– f. tempsky. prag and wien and g. freytag, leipzig, prag, wien, iv + 704 pp. suess, e. (1901): abschieds-vorlesung.– beitrage zur paläontologie und geologie gesellschaft österreich-ungarns und des orient, 14, 2–8. tozer, e.t. (1981): triassic ammonoidea: classification, evolution and relationship with permian and jurassic forms.– in: house, m.r. & senior, j.r. (eds.): the ammonoidea. the systematics association special volume, 18, 46–100. vinassa de regny, p. (1903): fossili del montenegro. i. fauna dei calcari rossi e grigi del sutorman.– memorie della reale accademia delle scienze dell'istituto di bologna, classe di scienze fisiche v, 10, 447–47. vörös, a. (2003): the pelsonian ammonoid fauna of the balaton highland. in: vörös, a. (ed.): the pelsonian substage on the balaton highland (middle triassic, hungary).– geologica hungarica: series palaeontologica, 55, 71–121. vörös a. (2018): the upper anisian ammonoids of the balaton highland (middle triassic, hungary).– geologica hungarica: series palaeontologica, 60, 1–241. wеndt, ј. (1973): cephalopod accumulations in the middle trassic hallstatt-limestone оf jugoslavia and greece.– neues јahrbuch für geologie und paläontologie, 10, 624–640. wendt, j. (2017): a unique fossil record from neptunian sills: the world’s most extreme example of stratigraphic condensation (jurassic, western sicily).– acta geologica polonica, 67, 163–199. http://doi.org/10.1515/agp-20170015 https://doi.org/10.2298/gabp230624008r https://doi.org/10.2298/gabp231117011s https://doi.org/10.2298/gabp231117011s 2018 | 71/2 | 65–81 | 6 figs. | 2 tabs. | 3 app. tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction the excessive application of chemical fertilizers and manures to agricultural lands has increased the influx of substances into the ground, which eventually reach and contaminate groundwater (spalding et al., 1982; umezawa et al., 2008; zhang et al., 2014). in order to identify the type of contamination, determine its extent, trace the source and extract valuable information about the groundwater such as its age, the water is sampled to measure stable isotope ratios, major and minor ion concentrations as well as trace metals. water and substances reaching aquifers serve as a guide to determining these groundwater characteristics (demlie et al., 2007; cloutier et al., 2008; hosono et al., 2014). usually in groundwater studies, a direct link is created between the characteristics of the groundwater and ions, isotopes and metals on the surface without taking the unsaturated zone into consideration even though substances pass through this zone before reaching groundwater. although the unsaturated zone has not been as actively studied as groundwater, studies have been carried out over the years that give some insight into the flow processes and solute behaviour through it (beven et al., 1982; guymon, 1994; lin et al., 2006). general unsaturated flow processes have also been studied. field experiments using clas a tracer were conducted on a mine waste pile (5 m high) to evaluate the infiltration rate and detect the dominant flow system in the pile (nichol et al., 2005). nimmo et al. (2007) modelled unsaturated zone flow using soil science and hydrologic data. the evaluations of the downward velocity of soil water movement in the unsaturated zone in a groundwater recharge area using δ18o tracer: the kumamoto region, southern japan azusa okumura1*, takahiro hosono1, dennis boateng2 and jun shimada1 1 kumamoto university, priority organization for innovation and excellence, 2-39-1 kurokami, kumamoto 860-8555, japan; (*corresponding author: osnx.2157@gmail.com) 2 kumamoto university, graduate school of science and technology, 2-39-1 kurokami, kumamoto 860-8555, japan doi: 10.4154/gc.2018.09 abstract water and substances from the surface infiltrate the unsaturated zone before reaching groundwater. yet, little study has been done on the unsaturated zone due to the difficulty of sampling. a lot of studies have been carried out on the top soil down to a depth of one metre and on shallow aquifers because they are easily accessible for sampling. the unsaturated zone of the kumamoto region recharge areas is important due to concerns about groundwater pollution from agriculture. the aim of this study was to estimate the downward velocity of soil water movement through the unsaturated zone and the recharge rate using δ18o as a tracer. five sampling sites were selected and a core was taken from each site. the cores were cut into 0.1 m pieces and soil water was extracted from each to analyze for δd and the δ18o content. average δd and δ18o compositions of soil water were similar to the isotopic compositions of summer precipitation. annual average recharge rate and the downward velocity of soil water in each site were estimated by fitting a vertical δ18o profile pattern to a precipitation δ18o time series as a theoretical water displacement flow model for recharge. an estimated annual average recharge rate in the recharge area ranged from 745 to 1058 mm/yr with the annual average downward velocity of 1.37 to 2.34 m/yr. based on the estimated downward velocity, the infiltration time for soil water to reach the aquifer was determined as ranging from 9 to 24 years, which corresponds with previous groundwater age estimations presented in an earlier published study on the same area. it was assumed that contaminants will reach aquifers in 9 to 25 years if the effects of diffusion and microbiological reaction are not taken into account. study focused on preferential flow and the general transport time was also clarified. delin et al. (2017) applied rhodamine and br tracers to a crude oil contaminated site to detect the influence of oil on the water infiltration rate in the unsaturated zone. these studies show that the plurality of flow processes such as prefe­ rential flow and matrix flow complicates water infiltration and contaminant behaviour through unsaturated media. understanding the behaviour of water in the unsaturated zone is important for making decisions about groundwater usage and formulating mitigation measures against groundwater contamination. one of the earliest soil water studies using water stable isotopes was performed by zimmermann et al. (1966). in this study, d2o was sprayed on the study area as a tracer. soil down to 1.2 m depth was sampled 4, 26, 82, 152 and 214 days after spraying for analysis. a time series hydrogen stable isotope profile of the soil water revealed that piston flow, which is the domi­ nant flow mechanism in near saturated formation, was excellent. several studies have also been carried out with oxygen and hydrogen stable isotopes as tracers in dry and semi­arid areas (barners & allison, 1983; de vries et al., 2000). in agriculture, soil at 1 m depth has been actively studied. however, studies on soil at far greater depths have rarely been undertaken (bharati et al., 2002). many different isotope tracers are used around the world based on the purpose and intent of a study. one of these tracers is tritium, a radioactive isotope of hydrogen. tritium used to be a good tracer for tracking water movement through the unsatuarticle history: manuscript received december 28, 2017 revised manuscript accepted may 28, 2018 available online june 21, 2018 keywords: soil water, oxygen isotope, unsaturated zone, recharge rate, infiltration time g eo lo gi a c ro at ic a geologia croatica 71/266 rated zone and determining groundwater age because of it abundance in the atmosphere. in the arid climate of arizona, it was used to determine the mixing degree between shallow and deep groundwater (harris, 2000). in the humid climate of japan, it was used as a tracer to determine the recharge rate and infiltration time (kayane et al., 1980; shimada, 1988). however, a few studies pointed out that tritium cannot be solely relied on because its concentration keeps on dropping year after year in the atmosphere (tsujimura & tanaka, 1998). consequently, in later studies, oxygen and hydrogen isotopes were used together instead as tracers to determine recharge rates especially in japan (yabusaki et al., 2011; kudo et al., 2016). both recharge rate and unsaturated zone infiltration velocity are important variables that provide insight into contaminant movement through the unsaturated zone. in this study, the study area as shown in figure 1, the kumamoto region, is almost 100% dependent on groundwater for drinking purposes. however, the nitrate concentration has begun to build up in the water, raising concerns about groundwater contamination (hosono et al., 2013). the high nitrate buildup occurs at high elevation areas which have lots of agricultural activities and are the recharge zones for kumamoto groundwater. it is therefore necessary to understand the infiltration mechanism in the unsaturated zone of these areas. recently, unsaturated zone soil samples (down to 5 m depth) were collected at the slope of the western foot of mt. aso and the amount of recharge was estimated using oxygen and hydrogen isotope ratios of the water extracted from the soil (kudo et al., 2016). research on the deep unsaturated zone (up to 15 m in depth) in kumamoto using isotope tracers is still limited. the aim of this study is to augment the efforts in unsaturated zone studies in the kumamoto region by trying to clarify the infiltration mechanism through estimation of the recharge amount and downward velocity of soil water using oxygen isotope ratios (water) in the recharge zone. 2. study area the kumamoto region is about 1041 km2 in area and bordered by the chikushi­mountains to the north, the mashiki­mountains to the south and the slope of the western foot of mt. aso to the east (figure 1). there are three main rivers in the region; the kikuchi, shira and midori rivers which all flow into the ariake sea. the hydrogeological basement of the kumamoto region consists of mesozoic metamorphic and igneous rocks. the basement rocks are overlain by quaternary pyroclastic flow deposits with high permeability (miyoshi et al., 2009). these deposits also cover the three major plateaus in the region which are the kikuchi and takayubaru plateaus to the east and the ueki plateau to the north (figure 1). they have altitudes of approximately 100 m. the unsaturated zone of these plateaus has a thickness of about 30 m. new volcanic ash layers are widely distributed on the top soil. the soil profiles of cores taken from the various sites studied are shown in figure 2. soil types include sandy clay, clay sand, volcanic ash sand, volcanic ash clay, gravelly clay, nonwelded tuff and gravel. there are variations in soil type among the cores. groundwater in the kumamoto region is recharged on the slope of mt. aso and around the plateaus, and flows from the northeastern part of the region to the southwest (taniguchi et al., 2003). the aquifer formed by quaternary pyroclastic flow deposits are divided into two main types by an aquiclude layer of lacustrine sediments; unconfined and confined aquifers (shifigure 1. a map showing the kumamoto region including sampling points. red points show the drilling sites of the cores. the black lines and pink lines highlight the shallow groundwater table in the high-water season and the plateau areas. g eologia c roatica okumura et al.: evaluations of the downward velocity of soil water movement in the unsaturated zone in a groundwater recharge area ... 67 mada, 2012). the land­cover is 31% farmland, 29% forest and 11% paddy. the plateaus, which are groundwater recharge areas are mainly used as farmland. average annual precipitation and temperature of kumamoto from 1985 to 2015 are 1986 mm and 16.9 ˚c, respectively. 3. sampling and methods in this study, 5 sampling sites were selected on the plateaus in the region (figure 1). each sampling site shows a different soil type, different fertilizer application method as well as treatment, different crops cultivated and different drilling times as shown in table 1 and figure 2. core samples were taken from the unsaturated zone of each site using an excavator without adding water (eco­3v, ybm, japan). the core was cut into 0.1 m samples and vacuum packed onsite to prevent evaporation of soil moisture before being taken to the laboratory for analysis. the 0.1 m fractions were split into two and each placed in a 100 cc sampling can. from one, soil water was centrifuged at pf 4.2 using centrifuge (model ss­2200, sakuma, japan) which spins for 2 hours. although different for each depth, 2 to 20 ml of soil water was extracted. for the other sample, a three­phase meter that operates by charles boyle’s law was used to measure the total volume of the liquid and solid phases after weighing (horita, 1985). the gas phase content (air within the pores) was obtained by subtracting the li­ quid and solid phase volumes from the total volume of the can. precipitation data used in this study was gathered at the kumamoto university from jan, 2005 to jul, 2016. the data was acquired by sampling rainfall two to three times every month in a 2000 ml plastic bottle equipped with a funnel. a ping­pong ball was placed in the funnel to prevent evaporation. samples were analyzed for hydrogen and oxygen isotope ratios. the results were converted to monthly data by evaluating the weighted ave­ rage for each month. figure 2. soil profiles of drilled cores of the various sites. table 1. details of sampling points. for the three-phase distribution, samples at 0.9 – 1.0 m, 5.0 – 5.1 m and 9.9 – 10.0 m are displayed. details of all the water content data of the cores are shown in appendix table a1.   altitude(m) cultivated crop type drilling date depth (m) application status of fertilizers threephase distribution (%) total soil water content (mm)   0.9–1.0 m 5.0–5.1 m 9.9–10.0 m 0–1.0 m 0–5.0 m 0–10 m s1 98 corn for feed and italian ryegrass nov-14 15 slurry and fertilizers gas 9 14 45 580 2689 5331liquid 64 53 31 solid 27 33 24 s2 67 corn for feed and italian ryegrass nov-14 14 slurry and fertilizers gas 29 1 25 501 2729 5036liquid 53 57 34 solid 18 42 41 c1 105 vegetable may-12 20 chemical fertilizers gas 26 18 18 523 2345 4994liquid 55 52 47 solid 19 30 35 c2 121 vegetable may-12 15 chemical fertilizers gas 27 17 16 540 3175 5729liquid 58 54 50 solid 15 29 34 c3 137 carrot sep-15 10 manure and fertilizers gas 26 12 5 536 3203 6249liquid 62 64 51 solid 12 24 44 g eo lo gi a c ro at ic a geologia croatica 71/268 hydrogen and oxygen isotope ratios were measured by mass spectrometer (delta­v, thermo fisher scientific, usa). in the mass spectrometer, the gas achieved equilibrium with the oxygen and hydrogen isotopes of the water samples that were introduced. the hydrogen and oxygen isotopes are expressed as relative differences (δ values) from standard mean ocean water in per mil (‰). the accuracy of the measured value was within ± 0.50‰ for δd and within ± 0.05‰ for δ18o. 4. results plots of δd and δ18o for all precipitation and soil water samples are shown in figure 3. the elevation effect on water isotopes was evaluated. the maximum elevation difference between the cores was calculated to be 70 m. this elevation effect on the hydrogen isotope in the study area is reported as -0.027‰ per metre (kagabu et al., 2017). hence, the maximum elevation effect of the sampling points is about 1.9‰. however, it can be seen from figure 3 that all plots of δd and δ18o fall along the summer local meteoric water line (april to september) regardless of elevation effect. therefore, it was not considered in our estimations. the isotope ratios of precipitation for 11 years (2005 to 2015) were divided into two groups depending on season; summer (april to september) and winter (october to march). the slopes of the regression lines of the summer and winter data are 8.5 (r2 figure 3. a plot diagram for δ18o against δd of soil water samples. figure 4. oxygen stable isotope ratio vertical profile diagrams for each core. triangle marks show peak depth with a relatively high isotope ratio. g eologia c roatica okumura et al.: evaluations of the downward velocity of soil water movement in the unsaturated zone in a groundwater recharge area ... 69 = 0.87, p < 0.0001, n = 70) and 8.0 (r2 = 0.84, p < 0.0001, n = 65) respectively, which are almost equal to 8, the slope of the world meteoric water line (craig, 1961). however, the intercept of the regression line for summer and winter data are 12.8 and 19.2, respectively. the intercept for all soil water was 8.8 (r2 = 0.83, p < 0.01, n = 566) which was relatively close to the intercept for summer (figure 3). moreover, the averages of δd and δ18o of soil water samples were –41.3‰ and –6.7‰, respectively which are similar to the isotopic composition for summer precipitation (δd = –45‰, δ18o = –7‰) compared with that of winter (δ18o = –5‰, δd = –32‰). evaporation occurring in the soil is generally considered to be non­equilibrium evaporation, in which case the slope of a regression line in the soil water tends to be smaller ranging from 2 to 5 (barnes & turner, 1998; clark & fritz, 1997). in this study, the slope for all soil water sample plots was 8.1 (r2 = 0.83, p < 0.01, n = 566), which implies evaporation in the top soil was not considerable. figure 4 shows the vertical profiles of δ18o in soil water. these profiles display several relatively high isotopic composition peaks, e.g., at depths of 1.2 m and 3.5 m for the s1 core. it is interpreted that the vertical change of δ18o is reflective of the seasonal isotopic composition of the recharging precipitation which is high in summer and low in winter. these peaks hold the seasonal information of precipitation. the plots in figure 4 show that it takes one year for new peaks to appear on the profile. it can be inferred from the s1 core profile that the infiltration rate in the top 3.5 m would be 2.2 m/yr approximately. the next peak after 3.5 m is at 10 m depth. therefore, the depth interval from peak to peak is observed to be increasing. moreover, there is a gradual change in peak compared with the peak at 3.5 m depth. the profiles of the other cores show similar characteristic peaks. it is assumed that as soil water infiltrates deeper, the more dispersion may occur when the peaks are averaged. therefore, there is a limit to understanding the infiltration rate from the peak position. table 1 shows the liquid and solid phases at depths of 1 m, 5 m and 10 m for each core. in all cores, the solid phase varies between 15% and 27% at 1 m depth, while porosity ranges between 73 and 88%. according to shimozu (1986), mt. aso volcanic ash soil porosity ranges from approximately 70 to 90%. hence, the sampling points have the characteristics of volcanic ash soil. the s1 liquid at 10 m depth is small compared with other cores. on the other hand, in c3, the liquid phase occupies 96% of the pore volume at a depth of 10 m. in particular, c3 has a high liquid phase at all depths. therefore, c3 soil is considered to have a relatively high water holding capacity. it is important to determine the recharge rate and downward velocity of soil water by incorporating a water content profile. 5. discussion in order to estimate the average downward velocity of soil water from 0–15 m depth using stable isotope ratios, the isotope profile of soil water was compared with the model isotope profile of the monthly infiltration amount obtained by subtracting evapotranspiration from precipitation. in building the model profile based on precipitation, the time-series data of precipitation was converted into depth data. to do this, the displacement flow model (dfm) proposed by anderson & sevel (1974) was applied. dfm was used earlier by shimada (1988) and kudo et al. (2016) to understand the behaviour of water in the unsaturated zone. the model assumes a piston flow. here, a piston flow is also assumed in an attempt to estimate the recharge rates and the downward velocity. the methods used to calculate dfm are described below. equation (1) which is the water balance equation was used to estimate infiltration (i) into the ground. i = p-r-e (1) where p, r and e are amounts of precipitation, runoff and evapo­ transpiration, respectively. in estimating e, equation (2) was used. this is a modified form of thornthwaite’s equation (thornthwaite, 1948) used to handle wide temperature ranges. this is based on the principle that the amounts of precipitation and evapotranspiration are directly proportional to the atmospheric pressure (takahashi, 1979). 2 3100pe(t) = 34.4t3100 +1.8p exp(– ) 235 + t (2) where t is monthly temperature, p is monthly precipitation. here, r in equation (1) was replaced with αp by setting the direct runoff coefficient α, assuming that a constant rate of p directly flows out. α was varied from 0 to 0.3 at an interval of 0.02 with reference to kudo et al. (2016), and the highest coefficient of determination between the actual profile and the modeled profile was selected. the fraction of monthly precipitation used for each depth was determined to successively represent infiltration from the surface which corresponds to the soil water content. based on the fraction of the monthly precipitation for each depth, weighted averages of the oxygen isotope ratios in precipitation were estimated to create a model isotope vertical profile (tsujimura et al., 1994). dfm was used to create a depth profile by applying the time variation of the tracer concentration. the downward velocity of soil water and recharge rate were estimated based on the depth­ time information obtained when the profile was created using dfm. monthly temperature and precipitation data for kumamoto city collected by the japan meteorological agency were used in the dfm. time series data used in the dfm calculations are shown in figure 5 and include precipitation, evapotranspiration, temperature and δ18o in precipitation. the profile of δ18o in soil water and that of the modeled profile by dfm are shown in figure 6. the coefficient of determination (r2) between the measured δ18o and modeled δ18o by dfm was lower than 0.5 for all cores (black line vs gray line in figure 6). this indicates that direct results by dfm could not trace the behaviour of measured δ18o profile successfully. this may be due to the fact that input precipitation δ18o data are based on a weighted average of several precipitation events and did not cover precisely all actual precipitation δ18o records. moreover, the concept of the dfm model might be the other reason which does not account for dispersion phenomena. to solve this problem, variance due to these factors was considered by calculating moving averages of dfm values and the condition that resulted in the highest correlation between measured δ18o and modeled δ18o was employed (kudo et al., 2016). consequently, we found the best condition resulting in the highest correlation between mea­ sured δ18o and modeled δ18o (moving average dfm), as shown by the black and dotted lines in figure 6. the coefficient of determination for all cores was (r2> 0.8, p <0.02), suggesting that g eo lo gi a c ro at ic a geologia croatica 71/270 figure 5. time series distribution of (a) precipitation (b) temperature (c) evapotranspiration (d) oxygen isotope ratio in precipitation (e) monthly average of precipitation (bar graph) and oxygen isotope ratio (line graph) from 2005 to 2015. the dotted lines in (a) and (d) represent the moving average of 3 month data. the hatched area in (d) represents the summer season (april – september). table 2. infiltration time and velocity of studied cores estimated using dfm. the thickness of the unsaturated zone is estimated using shallow groundwater level distribution. s1 s2 c1 c2 c3 1058 846 745 795 869 2.34 1.68 1.46 1.38 1.37 30 15 33 33 19 13 9 23 24 14average water transportation time from surface reaching to aquifer (yr) annual average of recharge rates (mm/yr) annual average of downward velocity (m/yr) thickness of unsaturated layer (m) g eologia c roatica okumura et al.: evaluations of the downward velocity of soil water movement in the unsaturated zone in a groundwater recharge area ... 71 our dfm approach satisfactorily reflects water behaviour at the studied sites. the estimated result for each site is shown in table 2. in s1, it was observed that the downward velocity was the highest of all the sites. this is because the soil has a low liquid phase around 10 m depth. comparing c3 and s1 which have the same soil type, s1 has a higher recharge rate and velocity. this may be due to the difference in soil conditions. for c3 and s2, it can be seen that the downward velocity of c3 is relatively lower, even though the recharge rate is higher. the most likely reason is that, c3 soil has the highest water content (table 1). therefore, it is evident that the difference in the average recharge rate and downward velo­ city for each core is due to the difference in soil conditions such as soil type and water content at each core depth (table 1 and figure 2). although there are regional differences, the annual average recharge rate in the recharge area of the plateau was estimated to range from 745 to 1058 mm/yr, and the annual average downward velocity from 1.37 to 2.34 m/yr. furthermore, the average recharge rate and average downward velocity calculated from the estimation results in table 2 for s1, c2 and c3 in the northeastern recharge area (figure 1) are 893 mm/yr and 1.7 m/yr, respectively. these somehow match the recharge amount of 1137 mm/ yr and infiltration rate of 2.3 m/yr of the kumamoto region estimated using tritium (shimada & ueno, 2016). however, our estimated value was smaller than that of shimada & ueno (2016). the difference may be due to regional heterogeneities. in estimating the infiltration time for water to reach the aquifers, the unsaturated zone thickness was divided by the downward velocity as shown in table 2. the unsaturated zone thickness was obtained by subtracting the groundwater level elevation in the lowest water level period at the sampling points from the ground surface elevation. the transportation time from the ground surface to the aquifer was estimated to range from 9 to 24 years. kagabu et al. (2017) estimated the ages of groundwater in the recharge zone at kikuchi plateau using 85kr age tracer to range from 15 to 25 years (n = 3). although different sample points were selected in this study, the water transportation time from the surface to the aquifer estimated by dfm is equivalent to the recharge area’s groundwater ages calculated by kagabu et al. (2017). therefore, it can be reliably concluded that soil water reaches the aquifer over a period of about 9 to 25 years in the main recharge area of the kumamoto region. 6. conclusion the recharge rate and downward velocity in the unsaturated zone of the recharge area of the kumamoto region were estimated for 5 soil cores using oxygen isotope ratios in soil water as a tracer. consequently, the annual average recharge rate was estimated to range from 745 to 1058 mm/yr, and the annual average downward velocity from 1.37 to 2.34 m/yr. differences in the estimated recharge rate and downward movement velocity are due to the variation in soil properties of each site. water transportation time from the surface to the aquifers was estimated to be 9 to 24 years, corresponding well to groundwater ages in the same recharge area. with the assumption that nitrogen loaded on the surface will be transported with soil water, nitrate should leach to the aquifer in 9 to 24 years once fertilizers and manures are applied. such information is primarily important for the management and preservation of groundwater resources. however, nitrate transportation and behaviour in the unsaturated zone should be affected by diffusion, microbial activities, etc. the results of this study therefore may not be able to fully account for the transportation of so­ lutes through the unsaturated zone to the aquifers. to better understand nitrate infiltration characteristics, it is necessary to promote future studies on nitrate concentrations and isotope ratios to aid further understanding of soil water infiltration mechanisms. acknowledgment we thank mr. satoshi sakaeda of the kumamoto prefectural government for his help during the field surveys. we also thank associate prof. kimpei ichiyanagi, graduate school of science and technology of kumamoto university for his support with rainfall sampling. we express our gratitude to ms. miho masaki for making available her soil profile data set for this work. finally, we wish to thank the farmers who readily made available their fields for this study. this study was funded by commissioned research of kumamoto prefectural government. figure 6. the profile of measured δ18o values in soil water (black line), dfm (gray line) and the moving average of dfm (dotted line). g eo lo gi a c ro at ic a geologia croatica 71/272 references andersen, l.j. & sevel, t. (1974): six years environmental tritium profiles in the unsaturated zones, gronhoj, denmark.– isotope techniques in groundwater hydrology, iaea vienna, 1, 3–20. baharati, l., lee, k.h., isenhart, t.m. & schultz, r.c. (2002): soil­water infiltration under crops, pastures, and established riparian buffer in midwestern usa.– agroforestry systems, 56, 249–257. barnes, c. & allison, g.b. (1983): the distribution of deuterium and 18o in dry soils, 1 theory.– journal of hydrology, 60, 141–156. doi: 10.1016/0022­ 1694(83)90018­5 barnes, c.j. & turner, j.v. (1998): isotopic exchange in soil water – isotope tra­ cers.– in: kendall, c. & mcdonnell, j.j. (eds.): catchment hydrology, elsevier amesterdam, 137–163. doi: 10.1016/b978­0­444­81546­0.50012­4 barth, s.r. (2000): stable isotope geochemistry of sediment­hosted groundwater from a late paleozoic-early mesozoic section in central europe.– journal of hydrology, 235, 72–87. doi: 10.1016/s0022­1694(00)00264­x beven, k. & germann, p. (1982): macropores and water flow in soils.– water resources research, 18, 1311–1325. doi: 10.1029/wr018i005p01311 clark, i. & fritz, p. (1997): groundwater – environmental isotopes in hydrogeo­ logy.– crc press/lewis publishers, 85–89. cloutier, v., lefebvre, r., therrien, r & savard, m.m. (2008): multivariate statistical analysis of geochemical data as indicative of the hydrogeochemical evolution of groundwater in sedimentary rock aquifer system.– journal of hydrology, 353, 294–313. doi: 10.1016/j.jhydrol.2008.02.015 craig, h. (1961): isotope variations in meteoric waters.– science, 133, 1702–1703. de vries, j.j., selaolo, e.t. & beekman, h.e. (2000): groundwater recharge in the kalahari, with reference to paleo-hydrologic conditions.– journal of hydrology, 238, 110–123. doi: 10.1016/s0022­1694(00)00325­5 delin, g.n. & herkelrath, w.n. (2017): effects of crude oil on water and tracer movement in the unsaturated and saturated zones.– journal of contaminant hydrology, 200, 49–59. doi: 10.1016/j.jconhyd.2017.03.007 demlie, m., wohnlich, s., wisotzky, f. & gizaw, b. (2007): groundwater recharge, flow and hydrogeochemical evolution in a complex volcanic aquifer system, central ethiopia.– hydrogeology journal, 15, 1169–1181. guymon, g.l. (1994): preface and introduction – unsaturated zone hydrology.– p.t.r. prentice hall, 1–6. harris, r.c. (2000): tritium as a tracer of groundwater sources and movement in the safford basin, graham county, arizona.– arizona geological survey, 9, 1–56. horita, y. (1985): the measurement of physical soil by the actual volume.– research of forest in kyusyu, 38, 139–141 (in japanese). hosono, t., tokunaga, t., kagabu, m., nakata, h., orishikida, t., lin, i.t. & shimada, j. (2013): the use of δ15n and δ18o tracers with an understanding of groundwater flow dynamics for evaluating the origins and attenuation mechanisms of nitrate pollution.– water research, 47, 2661–2675. hosono, t., tokunaga, t., tsushima, a. & shimada, j. (2014): combined use of δ13c, δ15n, and δ34s tracers to study anaerobic bacterial processes in groundwater flow systems.– water research, 54, 284–296. hem, j.d. (1985): study and interruption of the chemical characteristics of natural water.– united states geological survey water-supply paper, 2254, 174–180. johnstorn, g.t., cook, p.g., frape, s.k., plummer, l.n., busenberg, e. & blackport, r.j. (1998): groundwater age and nitrate distribution within a glacial aquifer beneath a thick unsaturated zone.– ground water, 36, 171–180. kayane, t., tanaka, t. & shimada, j. (1980): the transportation of soil water in kanto loam formation using environmental tritium as a tracer.– geographical review of japan, 53–4, 225–237 (in japanese). kabeya, n., ohte, n., sugimoto, a., yoshikawa, k. & wang, l. (2002): effects of the ground cover conditions on horizontal profiles of chloride concentration, oxygen and hydrogen stable isotope ratios of groundwater in mu us desert, china.– journal of japan society of hydrology and water resources, 15, 13–22 (in japanese with english abstract). doi: 10.3178/jjshwr.15.13 kagabu, m., matsunaga, m., ide, k., momoshima, n. & shimada, j. (2017): groundwater age determination using 85kr and multiple age tracers (sf6, cfcs and 3h) to elucidate regional groundwater flow systems.– journal of hydrology, regional studies, 12, 165–180. kudo, k., shimada, j., maruyama, a. & tanaka, n. (2016): the quantitative evaluation of groundwater recharge rate using displacement flow model with stable isotope ratio in the soil water of different vegetation cover.– journal of japan association of groundwater hydrology, 58, 31–45 (in japanese with english abstract). doi: 10.5917/jagh.58.31 lin, r. & wei, k. (2006): tritium profiles of pore water in the chinese loess unsaturated zone: implications for estimation of groundwater recharge.– journal of hydrology, 328, 192–199. doi: 10.1016/j.jhydrol.2005.12.010 mahara, y. (1995): noble gases dissolved in groundwater in a volcanic aquifer: helium isotopes in kumamoto plain.– environmental geology, 25, 214–224. doi: 10.1007/bf00766749 miyagima, t. & nagata, s. (2008): the stable isotope and the evaluation of watershed environment.– the academic publisher in kyoto university, japan, 59–65 (in japanese). miyoshi, m., furukawa, k., shinmura, t., shimono, m. & hasenaka, t. (2009): petrography and whole­rock geochemistry of pre­aso lavas from the caldera wall of aso volcano, central kyusyu.– journal of the geological society of japan, 115, 672–687. (in japanese with english abstract). nichol, c., smith, l. & beckie, r. (2005): field­scale experiments of unsaturated flow and solute transport in a heterogeneous porous medium.– water resour. res., 41/5, w05018. doi: 10.1029/2004wr003035 nimmo, j.r. (2007): simple predictions of maximum transport rate in unsaturated soil and rock.– water resour. res., 43/5, http://onlinelibrary.wiley.com/ doi/10.1029/2006wr005372/pdf. doi: 10.1029/2006wr005372 russell, e.w. (1973): soil conditions and plant growth.– 10th ed., longman, london. shimada, j. (1988): the mechanism of unsaturated flow through a volcanic ash layer under humid climatic conditions.– hydrological processes, 2, 43–59. doi: 10.1002/hyp.3360020105 shimada, j. (2012): sustainable management of groundwater resources for 700.000­plus residents: a practional example of the transboundary management of groundwater resources in the kumamoto area, japan. the dilemma of bounda ries. taniguchi, m. & shiraiwa, t. (eds.) springer japan, 235–246. doi: 10.1007/978­4­431­54035­9_20 shimada, j. & ueno, m. (2016): the challenge to sustainable groundwater use.– seibundo, 8, 144–151 (in japanese). shimozu, m. (1986): on the characteristics of groundwater in the hydrologic cycle of the aso volcano.– journal of japan association of groundwater hydrology, 28, 1–13. spalding, r.f., exner, m.e., lindau, c.w. & eaton, d.w. (1982): investigation of source of groundwater nitrate contamination in burbank­wallula area of washington, u.s.a.– journal of hydrology, 58, 307–324. doi: 10.1016/0022­ 1694(82)90041-5 takahashi, k. (1979): expression to estimate evapotranspiration using monthly ave­ rage temperature and monthly precipitation.– journal of meteorological society of japan, 26, 29–32 (in japanese). taniguchi, m., shimada, j. & uemura, t. (2003): transient effects of surface temperature and groundwater flow on subsurface temperature in kumamoto plain, japan.– physics and chemistry of the earth, 28, 477–486. doi: 10.1016/s1474­ 7065(03)00067­6 thornthwaite, c.w. (1948): an approach toward a rational classification of climate.– geographical review, 38, 55–94. doi: 10.2307/210739 tomiie, k., iwasa, y., maeda, k., otsuzuki, m., yunoue, t., kakimoto, r. & kawagoshi, y. (2009): present status and feature of groundwater contamination by nitrate­nitrogen in kumamoto city.– journal of water and environment technology, 7, 19–28. doi: 10.2965/jwet.2009.19 tsujimura, m. (1994): dynamic behaviour of soil water movement in a headwater basin.– unpubl. ph.d thesis, university of tsukuba, japan, 132 p. tsujimura, m. & tanaka, t. (1998): evaluation of evaporation rate from fo­ rested soil surface using stable isotopic composition of soil water in a headwater basin.– hydrological processes, 12, 2093–2103. doi: 10.1002/(sici)1099­ 1085(19981030)12:13/14%3c2093::aid­hyp722%3e3.0.co;2­c umezawa, y., hosono, t., onodera, s., siringan, f., buapeng, s., delinom, r., yoshimizu, c., tayasu, i., nagata, t. & taniguchi, m. (2008): source of nitrate and ammonium contamination in groundwater under developing asian megacities.– science of the total environment, 404, 361–376. doi: 10.1016/j.scitotenv.2008.04.021 yabusaki, s., tase, n. & shimada, j. (2011): vertical profile of stable isotopes in soil water through the volcanic ash soil layer in japan.– the earth environmental research, 13, 43–57 (in japanese with english abstract). zhang, y., li, f., zhang, q., li, j. & liu, q. (2014): tracing nitrate pollution sour­ ces and transportation in surfaceand ground-waters using environmental isotopes.– science of total environment, 490, 213–222. zimmermann, u., ehhalt, d., munnich, k.o., roether, w., kreutz, w., schubach, k. & sirgel, o. (1966): using tracers to determine movement of soil moisture and evapotranspiration.– science, 152, 346–347. land use control back­up system (may 11, 2017). land use control back­ up system, retrieved from http://lucky.tochi.mlit.go.jp/ japan meteorological agency (march 20, 2018), past climate data, retrieved from http://www.data.jma.go.jp/gmd/risk/obsdl/index.php g eologia c roatica okumura et al.: evaluations of the downward velocity of soil water movement in the unsaturated zone in a groundwater recharge area ... 73 appendix table a1 isotope composition of soil water in each core. depth (m) δd (‰) δ18o (‰) d-excess (‰) δd (‰) δ18o (‰) d-excess (‰) δd (‰) δ18o (‰) d-excess (‰) 0.0 0.1 -42.1 -7.13 14.94 -23.5 -4.18 9.95 -64.1 -8.84 6.61 0.10.2 -27.9 -4.93 11.54 -25.8 -4.57 10.79 -72.8 -10.35 10.07 0.2 0.3 -36.3 -5.71 9.38 -33.6 -5.08 7.03 -56.2 -8.34 10.53 0.3 0.4 -42.2 -6.55 10.20 -38.7 -5.69 6.87 -44.3 -6.66 9.00 0.4 0.5 -45.3 -6.84 9.42 -41.2 -5.91 6.11 -42.8 -6.09 5.91 0.5 0.6 -50.0 -7.27 8.16 -45.82 -6.16 3.43 -45.8 -6.35 5.03 0.6 0.7 -56.5 -7.94 7.02 -50.2 -6.77 3.99 -47.4 -6.48 4.43 0.7 0.8 -56.7 -7.97 7.06 -55.2 -7.36 3.69 -48.7 -6.90 6.46 0.8 0.9 -54.1 -7.67 7.26 -59.9 -7.88 3.15 -47.3 -6.84 7.36 0.9 1.0 -50.8 -7.24 7.12 -61.0 -7.97 2.77 -45.0 -6.64 8.11 1.0 1.1 -47.0 -6.76 7.08 -59.0 -7.82 3.53 -41.9 -6.29 8.34 1.1 1.2 -46.4 -6.61 6.48 -52.1 -6.95 3.51 -70.5 -7.09 -13.80 1.2 1.3 -45.9 -6.63 7.14 -41.1 -5.77 5.04 -39.1 -6.07 9.45 1.3 1.4 -46.6 -6.76 7.48 -33.6 -5.12 7.34 -33.8 -5.40 9.45 1.4 1.5 -48.1 -6.92 7.26 -50.3 -7.39 8.87 -29.5 -4.87 9.45 1.5 -1.6 -49.4 -7.16 7.88 -44.5 -6.54 7.84 -29.5 -4.76 8.55 1.6 1.7 -53.0 -7.48 6.84 -36.7 -6.13 12.28 -31.0 -4.80 7.36 1.7 1.8 -53.6 -7.59 7.12 -38.1 -6.22 11.65 -33.9 -5.09 6.80 1.8 1.9 -54.1 -7.75 7.90 -42.1 -6.19 7.43 -35.3 -5.38 7.75 1.9 2.0 -53.8 -7.74 8.12 -44.5 -5.95 3.12 -38.6 -5.86 8.25 2.0 2.1 -52.8 -7.74 9.12 -44.5 -6.24 5.37 -41.5 -6.12 7.47 2.1 2.2 -52.1 -7.69 9.42 -43.1 -6.13 5.92 -43.3 -6.32 7.23 2.2 2.3 -50.8 -7.62 10.16 -43.4 -6.06 5.01 -43.2 -6.34 7.49 2.3 2.4 -48.7 -7.44 10.82 -43.9 -6.03 4.28 -44.2 -6.47 7.54 2.4 2.5 -47.5 -7.40 11.70 -43.8 -6.08 4.82 -43.6 -6.38 7.42 2.5 2.6 -46.5 -7.27 11.66 -43.5 -6.05 4.97 -43.9 -6.44 7.56 2.6 2.7 -44.8 -7.15 12.40 -43.7 -6.00 4.33 -44.2 -6.42 7.17 2.7 2.8 -43.3 -6.94 12.22 -43.3 -6.06 5.14 -44.8 -6.45 6.80 2.8 2.9 -41.8 -6.81 12.68 -43.2 -5.90 4.06 -44.6 -6.44 6.90 2.9 3.0 -41.7 -6.60 11.10 -44.0 -5.93 3.48 -44.7 -6.38 6.37 3.0 3.1 -41.3 -6.67 12.06 -46.8 -6.23 3.05 -45.6 -6.64 7.51 3.1 3.2 -40.6 -6.68 12.84 -48.3 -6.42 3.05 -45.8 -6.61 7.16 3.2 3.3 -40.3 -6.51 11.78 -49.6 -6.50 2.42 -46.7 -6.74 7.17 3.3 3.4 -40.8 -6.61 12.08 -51.7 -6.69 1.89 -47.0 -6.82 7.61 3.4 3.5 -43.5 -6.15 5.70 -52.9 -6.91 2.40 -48.0 -6.89 7.10 3.5 3.6 -44.8 -6.22 4.96 -52.4 -6.97 3.30 -48.4 -6.96 7.30 3.6 3.7 -46.4 -6.48 5.44 -51.9 -7.20 5.63 -47.2 -6.78 7.05 3.7 3.8 -47.5 -6.52 4.66 -54.3 -7.14 2.77 -48.4 -6.81 6.07 3.8 3.9 -47.9 -6.53 4.34 -56.7 -7.62 4.22 -49.0 -6.93 6.43 3.9 4.0 -49.0 -6.74 4.92 -57.8 -7.76 4.26 -49.4 -6.97 6.34 4.0 4.1 -49.3 -6.77 4.86 -60.0 -8.03 4.30 -50.8 -7.09 5.88 4.1 4.2 -49.6 -6.92 5.76 -60.3 -8.19 5.27 -51.9 -7.20 5.68 4.2 4.3 -49.9 -7.03 6.34 -61.3 -8.22 4.47 -52.3 -7.15 4.91 4.3 4.4 -50.0 -7.06 6.48 -60.8 -8.24 5.06 -52.5 -7.21 5.17 4.4 4.5 -50.0 -7.06 6.48 -60.6 -8.14 4.48 -52.8 -7.23 5.00 4.5 4.6 -50.4 -7.15 6.80 -59.7 -8.00 4.28 -51.7 -6.99 4.21 4.6 4.7 -51.6 -7.37 7.36 -59.9 -8.09 4.84 -53.1 -7.29 5.19 4.7 4.8 -52.5 -7.56 7.98 -60.2 -8.11 4.71 -52.7 -7.18 4.77 4.8 4.9 -53.8 -7.83 8.84 -58.4 -7.83 4.26 -53.2 -7.35 5.64 4.9 5.0 -54.9 -7.96 8.78 -56.7 -7.67 4.69 -53.20 -7.39 5.95 5.0 5.1 -57.2 -8.18 8.24 -57.6 -7.96 6.08 -53.2 -7.44 6.27 5.1 5.2 -58.1 -8.46 9.58 -57.7 -7.92 5.58 -53.6 -7.42 5.74 5.2 5.3 -58.6 -8.40 8.60 -57.6 -7.84 5.10 -53.2 -7.47 6.48 5.3 5.4 -58.9 -8.50 9.10 -53.8 -7.60 7.01 -53.2 -7.45 6.38 5.4 5.5 -58.5 -8.44 9.02 -53.9 -7.60 6.90 -53.3 -7.49 6.66 5.5 5.6 -58.8 -8.40 8.40 -53.0 -7.43 6.45 -52.5 -7.27 5.67 5.6 5.7 -58.2 -8.38 8.84 -53.3 -7.42 6.07 -52.9 -7.31 5.57 5.7 5.8 -58.1 -8.37 8.86 -52.8 -7.37 6.15 -52.8 -7.28 5.43 5.8 5.9 -58.1 -8.36 8.78 -52.2 -7.25 5.77 -53.0 -7.26 5.09 5.9 6.0 -58.1 -8.36 8.78 -51.5 -7.21 6.11 -52.9 -7.18 4.52 6.0 6.1 -57.4 -8.28 8.84 -49.8 -6.97 5.99 -52.3 -7.13 4.71 6.1 6.2 -57.4 -8.23 8.44 -50.0 -6.99 5.96 -52.6 -7.16 4.66 6.2 6.3 -57.0 -8.19 8.52 -49.3 -6.86 5.65 -52.7 -7.15 4.46 6.3 6.4 -56.1 -8.03 8.14 -49.2 -6.88 5.86 -53.3 -7.21 4.33 6.4 6.5 -57.0 -8.11 7.88 -48.9 -6.84 5.85 -53.2 -7.21 4.47 6.5 6.6 -57.0 -8.18 8.44 -49.2 -6.89 5.96 -52.8 -7.23 5.03 6.6 6.7 -55.8 -8.00 8.20 -48.2 -6.68 5.27 -52.2 -7.11 4.71 6.7 6.8 -55.5 -7.94 8.02 -48.6 -6.82 5.97 -48.6 -6.84 6.05 6.8 6.9 -55.5 -7.89 7.62 -47.4 -6.64 5.75 -45.8 -6.44 5.80 6.9 7.0 -54.0 -7.75 8.00 -47.4 -6.62 5.64 -43.5 -6.17 5.82 s2 core c3 cores1 core g eo lo gi a c ro at ic a geologia croatica 71/274 depth (cm) δd (‰) δ18o (‰) d-excess (‰) δd (‰) δ18o (‰) d-excess (‰) δd (‰) δ18o (‰) d-excess (‰) 7.0 7.1 -50.7 -7.62 10.26 -44.5 -6.47 7.30 -43.6 -6.07 4.99 7.1 7.2 -50.3 -7.58 10.34 -44.1 -6.56 8.36 -43.5 -6.09 5.21 7.2 7.3 -49.8 -7.6 11.00 -43.4 -6.44 8.03 -43.7 -5.97 4.06 7.3 7.4 -49.6 -7.49 10.32 -44.0 -6.50 7.98 -43.9 -6.31 6.59 7.4 7.5 -48.5 -7.43 10.94 -43.8 -6.44 7.77 -45.2 -6.25 4.78 7.5 7.6 -48.3 -7.35 10.50 -44.2 -6.51 7.94 -44.0 -6.31 6.48 7.6 7.7 -46.9 -7.27 11.26 -44.9 -6.59 7.83 -44.1 -6.35 6.69 7.7 7.8 -46.6 -7.21 11.08 -44.5 -6.49 7.47 -43.3 -6.20 6.30 7.8 7.9 -45 -6.98 10.84 -43.6 -6.40 7.55 -43.8 -6.33 6.90 7.9 8.0 -45.2 -7 10.80 -42.7 -6.13 6.29 -42.8 -6.12 6.21 8.0 8.1 -44.6 -6.86 10.28 -44.8 -6.52 7.39 -44.7 -6.45 6.90 8.1 8.2 -42.7 -6.81 11.78 -44.8 -6.48 7.09 -43.4 -6.24 6.47 8.2 8.3 -42.3 -6.71 11.38 -45.5 -6.66 7.73 -44.0 -6.33 6.64 8.3 8.4 -42 -6.64 11.12 -45.1 -6.67 8.25 -43.9 -6.36 6.95 8.4 8.5 -40.9 -6.59 11.82 -44.5 -6.53 7.72 -43.4 -6.26 6.64 8.5 8.6 -40.4 -6.48 11.44 -45.4 -6.59 7.39 -43.0 -6.40 8.24 8.6 8.7 -40.1 -6.45 11.50 -45.1 -6.54 7.26 -42.6 -6.43 8.86 8.7 8.8 -39.9 -5.26 2.18 -43.8 -6.17 5.58 -42.1 -6.45 9.50 8.8 8.9 -38.5 -6.31 11.98 -43.1 -6.10 5.69 -42.5 -6.36 8.40 8.9 9.0 -37.7 -6.24 12.22 -43.0 -6.23 6.86 -42.4 -6.33 8.21 9.0 9.1 -37.9 -6.18 11.54 -43.5 -6.27 6.67 -44.6 -6.61 8.28 9.1 9.2 -37.7 -6.21 11.98 -44.1 -6.45 7.51 -44.1 -6.49 7.82 9.2 9.3 -37.3 -6.08 11.34 -44.0 -6.41 7.29 -43.1 -6.46 8.54 9.3 9.4 -37.3 -6.14 11.82 -44.2 -6.42 7.12 -41.9 -6.20 7.72 9.4 9.5 -37.7 -6.08 10.94 -43.6 -6.30 6.76 -41.3 -6.17 8.08 9.5 9.6 -37.5 -6.02 10.66 -43.7 -6.40 7.54 -40.5 -6.14 8.63 9.6 9.7 -37.4 -6.01 10.68 -42.3 -6.05 6.08 -41.0 -6.16 8.34 9.7 9.8 -37 -5.94 10.52 -42.7 -6.09 6.07 -39.9 -6.04 8.44 9.8 9.9 -37.7 -6.04 10.62 n.d. n.d. n.d. -40.7 -6.02 7.47 9.9 10.0 -35.9 -5.67 9.46 -39.1 -5.32 3.53 -42.9 -6.41 8.33 10.0 10.1 -34.4 -5.21 7.28 -43.9 -6.28 6.38 -47.1 -6.81 7.41 10.1 10.2 -36.8 -5.68 8.64 -43.0 -6.36 7.86 10.2 10.3 -37.4 -5.84 9.32 -43.1 -6.34 7.64 10.3 10.4 -37.4 -5.79 8.92 -43.4 -6.44 8.06 10.4 10.5 -37.9 -5.14 3.22 -42.6 -6.41 8.68 10.5 10.6 -37.6 -6.08 11.04 -43.5 -6.34 7.24 10.6 10.7 -38.2 -6.76 15.88 -43.0 -6.46 8.68 10.7 10.8 -39 -6.82 15.56 -43.0 -6.32 7.59 10.8 1.09 -39.1 -6.8 15.30 -41.5 -6.13 7.59 10.9 11.0 -37.8 -6.49 14.12 -41.7 -6.09 7.02 11.0 11.1 -39.5 -6.7 14.10 -42.7 -6.30 7.71 11.1 11.2 -40.3 -6.82 14.26 -42.9 -6.37 8.00 11.2 11.3 -40.6 -6.64 12.52 -43.5 -6.40 7.76 11.3 11.4 -41.3 -6.68 12.14 -43.3 -6.36 7.60 11.4 11.5 -42.2 -6.76 11.88 -43.1 -6.32 7.53 11.5 11.6 -42.5 -6.73 11.34 -43.1 -6.30 7.36 11.6 11.7 -42.1 -6.65 11.10 -42.7 -6.17 6.73 11.7 11.8 -42.6 -6.64 10.52 -43.0 -6.18 6.45 11.8 11.9 -43.3 -6.67 10.06 -42.8 -6.11 6.01 11.9 12.0 -42.9 -6.48 8.94 -43.3 -6.15 5.95 12.0 12.1 -44 -6.63 9.04 -44.4 -6.51 7.63 12.1 12.2 -44.2 -6.6 8.60 -44.1 -6.47 7.70 12.2 12.3 -44.2 -6.86 10.68 -44.6 -6.53 7.64 12.3 12.4 -45 -6.93 10.44 -44.7 -6.59 8.07 12.4 12.5 -43.5 -6.36 7.38 -44.2 -6.54 8.13 12.5 12.6 -43.4 -6.38 7.64 -42.9 -6.53 9.29 12.6 12.7 -45.0 -6.46 6.68 -43.5 -6.42 7.90 12.7 12.8 -44.9 -6.53 7.34 -43.9 -6.48 7.97 12.8 12.9 -45.7 -6.75 8.30 -43.7 -6.41 7.60 12. 9 -13.0 -43.9 -6.49 8.02 -42.9 -6.22 6.84 13.0 13.1 -45.7 -6.91 9.58 -43.2 -6.28 7.02 13.1 13.2 -46.1 -7.00 9.90 -42.9 -6.34 7.79 13.2 13.3 -46.1 -7.06 10.38 -42.1 -6.23 7.74 13.3 13.4 -45.7 -7.08 10.94 -41.2 -6.14 7.98 13.4 13.5 -46.2 -7.10 10.60 -41.1 -6.06 7.38 13.5 13.6 -46.3 -7.08 10.34 -40.2 -5.86 6.71 13.6 13.7 -46.4 -7.07 10.16 -40.7 -5.95 6.95 13.7 13.8 -46.3 -6.92 9.06 -40.2 -5.91 7.12 13.8 13.9 -45.1 -6.93 10.34 -39.3 -5.79 7.03 13.9 14.0 -45.1 -6.97 10.66 -39.6 -5.84 7.10 14.0 14.1 -44.9 -6.97 10.86 14.1 14.2 -45.7 -7.08 10.94 14.2 14.3 -45.8 -6.47 5.96 14.3 14.4 -45.1 -6.37 5.86 14.4 14.5 -44.9 -6.29 5.42 14.5 14.6 -44.8 -6.45 6.80 14.6 14.7 -44.6 -6.60 8.20 14.7 14.8 -44.4 -6.64 8.72 14.8 14.9 -44.4 -6.31 6.08 14.9 15.0 -43.5 -6.11 5.38 s1 core s2 core c3 core table a1. continuation. g eologia c roatica okumura et al.: evaluations of the downward velocity of soil water movement in the unsaturated zone in a groundwater recharge area ... 75 depth (m) δd (‰) δ18o (‰) d-excess (‰) δd (‰) δ18o (‰) d-excess (‰) 0.0 0.2 -25.4 -3.01 -1.28 -26.3 -4.64 10.84 0.2 0.4 -24.8 -3.85 6.00 -26.7 -4.87 12.32 0.4 0.6 -28.0 -4.65 9.19 -33.8 -5.32 8.68 0.6 0.8 -30.1 -4.67 7.31 -41.4 -6.11 7.45 0.8 1.0 -39.3 -5.23 2.59 -50.6 -6.93 4.81 1.0 1.2 -55.7 -7.09 0.98 -36.3 -5.60 8.56 1.2 1.4 -61.1 -7.82 1.50 -29.6 -4.01 2.51 1.4 1.6 -59.8 -7.68 1.68 -58.9 -8.08 5.72 1.6 1.8 -50.9 -6.52 1.25 -57.2 -8.00 6.79 1.8 2.0 -36.5 -5.13 4.48 -51.4 -7.35 7.39 2.0 2.2 -40.6 -5.45 2.99 -44.7 -6.41 6.60 2.2 2.4 -38.5 -5.14 2.61 -43.1 -6.27 7.08 2.4 2.6 -36.1 -4.80 2.31 -40.2 -5.93 7.23 2.6 2.8 -65.7 -5.04 4.64 -37.9 -5.68 7.49 2.8 3.0 -32.7 -4.57 3.86 -36.4 -5.49 7.51 3.0 3.2 -32.5 -4.92 6.92 -35.2 -5.36 7.62 3.2 3.4 -29.6 -4.34 5.14 -34.9 -5.28 7.33 3.4 3.6 -29.8 -4.37 5.17 -35.6 -5.29 6.70 3.6 3.8 -30.0 -4.16 3.24 -36.6 -5.39 6.45 3.8 4.0 -32.2 -4.39 2.94 -39.3 -5.66 5.98 4.0 4.2 -35.9 -5.00 4.11 -41.5 -6.04 6.79 4.2 -4.4 -39.3 -5.48 4.59 -42.7 -6.15 6.44 4.4 4.6 -42.1 -5.81 4.38 -44.1 -6.34 6.55 4.6 4.8 -43.1 -5.81 3.38 -45.7 -6.52 6.44 4.8 5.0 -48.7 -6.58 3.99 -47.1 -6.67 6.28 5.0 5.2 -50.9 -6.88 4.11 -48.3 -6.84 6.42 5.2 5.4 -48.2 -6.39 2.90 -48.0 -6.91 7.25 5.4 5.6 -48.9 -6.71 4.73 -47.8 -6.87 7.08 5.6 5.8 -46.9 -6.44 4.59 -46.8 -6.80 7.61 5.8 6.0 -44.6 -6.20 4.98 -44.9 -6.50 7.11 6.0 6.2 -38.3 -5.28 3.92 -43.2 -6.28 7.10 6.2 6.4 -43.6 -6.34 7.14 -41.9 -6.19 7.65 6.4 6.6 -42.2 -5.96 5.49 -41.0 -6.06 7.52 6.6 6.8 -41.3 -5.87 5.67 -39.9 -5.85 6.92 6.8 7.0 -39.9 -5.58 4.72 -38.7 -5.75 7.27 7.0 7.2 -38.8 -5.19 2.76 -39.6 -5.92 7.73 7.2 7.4 -38.0 -5.13 3.05 -39.0 -5.73 6.87 7.4 7.6 -38.4 -5.19 3.16 -38.8 -5.72 7.00 7.6 7.8 -37.8 -5.18 3.63 -38.0 -5.54 6.35 7.8 8.0 -36.0 -4.86 2.90 -36.9 -5.39 6.26 8.0 8.2 -36.6 -4.92 2.74 -37.7 -5.56 6.80 8.2 8.4 -34.9 -4.72 2.88 -37.5 -5.65 7.64 8.4 8.6 -35.3 -4.78 2.94 -37.1 -5.57 7.42 8.6 8.8 -34.6 -4.93 4.85 -37.0 -5.55 7.41 8.8 9.0 -33.7 -4.80 4.75 -36.7 -5.49 7.23 9.0 9.2 -30.9 -4.22 2.86 -36.2 -5.43 7.18 9.2 9.4 -30.2 -4.29 4.07 -36.3 -5.48 7.54 9.4 9.6 -30.5 -4.38 4.53 -36.0 -5.37 6.99 9.6 9.8 -30.3 -4.40 4.98 -35.8 -5.30 6.53 9.8 10.0 -29.2 -4.02 2.94 -34.9 -5.15 6.32 c1 c2 table a1. continuation. g eo lo gi a c ro at ic a geologia croatica 71/276 depth(cm) δd (‰) δ18o (‰) d-excess (‰) δd (‰) δ18o (‰) d-excess (‰) 10.0 10.2 -27.5 -3.59 1.21 -35.1 -5.28 7.09 10.2 10.4 -24.7 -2.65 -3.51 -35.0 -5.30 7.45 10.4 10.6 -22.5 -2.20 -4.85 -35.0 -5.21 6.69 10.6 10.8 -23.9 -2.55 -3.55 -34.7 -5.19 6.84 10.8 11.0 -24.4 -2.69 -2.91 -34.0 -5.21 7.62 11.0 11.2 -28.0 -3.70 1.65 -35.2 -5.19 6.35 11.2 11.4 -27.5 -3.49 0.42 -34.2 -4.93 5.30 11.4 11.6 -26.3 -3.30 0.08 -33.6 -5.03 6.66 11.6 11.8 -29.1 -3.90 2.06 -32.9 -4.96 6.73 11.8 12.0 -26.1 -3.17 -0.75 -32.7 -4.69 4.80 12.0 12.2 -25.6 -3.14 -0.51 -33.0 -4.78 5.19 12.2 12.4 -27.1 -3.51 0.91 -32.5 -4.76 5.55 12.4 12.6 -25.8 -3.17 -0.44 -32.3 -4.70 5.32 12.6 12.8 -25.8 -3.12 -0.80 -32.5 -4.65 4.76 12.8 13.0 -26.3 -3.37 0.66 -30.4 -4.35 4.47 13.0 13.2 -24.0 -2.79 -1.60 -32.5 -4.55 3.93 13.2 13.4 -26.3 -3.49 1.61 -32.6 -4.65 4.58 13.4 13.6 -27.7 -3.84 2.99 -31.3 -4.56 5.15 13.6 13.8 -26.8 -3.63 2.28 -28.7 -3.72 1.06 13.8 14.0 -25.9 -3.38 1.13 -25.8 -3.24 0.04 14.0 14.2 -24.2 -2.89 -1.06 -27.0 -3.59 1.73 14.2 14.4 -24.8 -3.18 0.68 -23.7 -2.61 -2.79 14.4 14.6 -24.8 -3.13 0.22 -28.6 -3.89 2.51 14.6 14.8 -24.4 -3.06 0.11 -21.6 -2.13 -4.54 14.8 15.0 -20.5 -2.07 -3.97 -16.1 -1.16 -6.88 15.0 15.2 -22.7 -2.61 -1.79 15.2 15.4 -25.7 -3.38 1.34 15.4 15.6 -22.7 -2.52 -2.60 15.6 15.8 -25.0 -3.18 0.41 15.8 16.0 -20.9 -2.16 -3.56 16.0 16.2 -24.1 -2.93 -0.63 16.2 16.4 -24.4 -2.99 -0.42 16.4 16.6 -24.5 -3.11 0.34 16.6 16.8 -27.3 -3.67 2.03 16.8 17.0 -26.3 -3.32 0.27 17.0 17.2 -29.3 -3.99 2.62 17.2 17.4 -29.2 -3.89 1.87 18.4 17.6 -32.7 -4.47 3.02 17.6 17.8 -34.5 -4.73 3.32 17.8 18.0 -34.3 -4.46 1.41 18.0 18.2 -31.0 -3.67 -1.71 18.2 18.4 -34.6 -4.54 1.66 18.4 18.6 -37.5 -5.01 2.54 18.6 18.8 -38.2 -5.05 2.21 18.8 19.0 -38.9 -5.12 2.04 19.0 19.2 -40.2 -5.46 3.43 19.2 19.4 -39.7 -5.36 3.18 19.4 19.6 -39.5 -5.19 2.06 19.6 19.8 -39.7 -5.15 1.44 19.8 20.0 -35.4 -4.34 -0.61 c1 c2 table a1. continuation. g eologia c roatica okumura et al.: evaluations of the downward velocity of soil water movement in the unsaturated zone in a groundwater recharge area ... 77 gas phase liquid phase solid phase gas phase liquid phase solid phase 0.0 0.1 53 9.3 52 38.7 7.0 7.1 58 2.5 57 40.5 0.10.2 54 11.1 53 35.9 7.1 7.2 58 4.6 57 38.4 0.2 0.3 51 14.9 50 35.1 7.2 7.3 58 6.9 57 36.1 0.3 0.4 55 16 54 30 7.3 7.4 50 3.7 49 47.3 0.4 0.5 60 15 59 26 7.4 7.5 53 2.2 52 45.8 0.5 0.6 57 18.1 56 25.9 7.5 7.6 56 1.4 55 43.6 0.6 0.7 65 13 64 23 7.6 7.7 55 9.9 54 36.1 0.7 0.8 64 9.9 63 27.1 7.7 7.8 55 1.6 54 44.4 0.8 0.9 59 15.5 58 26.5 7.8 7.9 47 8.9 46 45.1 0.9 1.0 61 13.5 60 26.5 7.9 8.0 52 17.6 51 31.4 1.0 1.1 65 8.7 64 27.3 8.0 8.1 59 6 58 36 1.1 1.2 61 21.8 60 18.2 8.1 8.2 55 9.9 54 36.1 1.2 1.3 64 9 63 28 8.2 8.3 60 7.9 59 33.1 1.3 1.4 61 11.8 60 28.2 8.3 8.4 50 6 49 45 1.4 1.5 59 17.8 58 24.2 8.4 8.5 55 4.4 54 41.6 1.5 -1.6 49 12.6 48 39.4 8.5 8.6 43 7.2 42 50.8 1.6 1.7 52 19.2 51 29.8 8.6 8.7 56 7.4 55 37.6 1.7 1.8 51 19.9 50 30.1 8.7 8.8 59 3.4 58 38.6 1.8 1.9 51 11 50 39 8.8 8.9 55 11 54 35 1.9 2.0 46 27.9 45 27.1 8.9 9.0 57 3.5 56 40.5 2.0 2.1 57 27.5 56 16.5 9.0 9.1 51 17.9 50 32.1 2.1 2.2 61 11.8 60 28.2 9.1 9.2 45 20 44 36 2.2 2.3 59 27 58 15 9.2 9.3 41 28.8 44 27.2 2.3 2.4 60 18.8 59 22.2 9.3 9.4 38 36.5 37 26.5 2.4 2.5 54 21.9 53 25.1 9.4 9.5 34 35.3 34 30.7 2.5 2.6 57 19.5 56 24.5 9.5 9.6 30 44.7 29 26.3 2.6 2.7 53 11.9 52 36.1 9.6 9.7 32 20.7 35 44.3 2.7 2.8 62 14.75 61 24.25 9.7 9.8 34 32.1 33 34.9 2.8 2.9 51 26.2 50 23.8 9.8 9.9 33 20.9 38 41.1 2.9 3.0 48 13.8 47 39.2 9.9 10.0 32 45.1 31 23.9 3.0 3.1 46 21 45 34 10.0 10.1 33 n.d. n.d. n.d. 3.1 3.2 45 21.3 44 34.7 10.1 10.2 32 n.d. n.d. n.d. 3.2 3.3 45 21.6 44 34.4 10.2 10.3 32 47.5 32 20.5 3.3 3.4 50 14.1 49 36.9 10.3 10.4 34 36.6 33 30.4 3.4 3.5 49 18.6 48 33.4 10.4 10.5 31 46.9 29 24.1 3.5 3.6 48 25.2 47 27.8 10.5 10.6 29 46.5 28 25.5 3.6 3.7 48 27.5 47 25.5 10.6 10.7 28 34.7 30 35.3 3.7 3.8 48 28.9 47 24.1 10.7 10.8 28 30.8 27 42.2 3.8 3.9 50 23.2 49 27.8 10.8 1.09 27 33.8 28 38.2 3.9 4.0 45 27.5 44 28.5 10.9 11.0 25 30.8 25 44.2 4.0 4.1 42 34.7 41 24.3 11.0 11.1 28 39.9 28 32.1 4.1 4.2 48 25.5 47 27.5 11.1 11.2 30 37.3 29 33.7 4.2 4.3 51 19.6 50 30.4 11.2 11.3 29 36.5 28 35.5 4.3 4.4 53 19.3 52 28.7 11.3 11.4 28 33.7 27 39.3 4.4 4.5 54 11.7 53 35.3 11.4 11.5 28 36.1 29 34.9 4.5 4.6 53 10.8 52 37.2 11.5 11.6 28 40 27 33 4.6 4.7 54 14.7 53 32.3 11.6 11.7 30 40 27 33 4.7 4.8 53 10.9 52 37.1 11.7 11.8 33 22 32 46 4.8 4.9 52 19.2 51 29.8 11.8 11.9 29 40.1 25 34.9 4.9 5.0 55 15.4 54 30.6 11.9 12.0 25 39.4 25 35.6 5.0 5.1 54 14.3 53 32.7 12.0 12.1 26 46.3 24 29.7 5.1 5.2 59 2 58 40 12.1 12.2 28 35.7 27 37.3 5.2 5.3 60 4.8 59 36.2 12.2 12.3 28 48 26 26 5.3 5.4 60 9.8 59 31.2 12.3 12.4 28 40 27 33 5.4 5.5 59 17.8 58 24.2 12.4 12.5 28 46.8 25 28.2 5.5 5.6 57 14.9 56 29.1 12.5 12.6 28 30.6 27 42.4 5.6 5.7 57 15.4 56 28.6 12.6 12.7 28 32.5 27 40.5 5.7 5.8 54 11.2 53 35.8 12.7 12.8 28 31.4 27 41.6 5.8 5.9 55 12.9 54 33.1 12.8 12.9 26 44.4 23 32.6 5.9 6.0 53 13.2 52 34.8 12. 9 -13.0 24 42.2 24 33.8 6.0 6.1 58 0.7 57 42.3 13.0 13.1 25 40 27 33 6.1 6.2 60 3.1 59 37.9 13.1 13.2 26 30.7 26 43.3 6.2 6.3 64 7.7 63 29.3 13.2 13.3 29 30.5 27 42.5 6.3 6.4 62 7.9 61 31.1 13.3 13.4 31 32 30 38 6.4 6.5 59 7.3 58 34.7 13.4 13.5 31 32.7 27 40.3 6.5 6.6 64 0.8 63 36.2 13.5 13.6 32 38 31 31 6.6 6.7 61 6.3 60 33.7 13.6 13.7 32 31.9 29 39.1 6.7 6.8 63 7.1 62 30.9 13.7 13.8 33 38.8 32 29.2 6.8 6.9 62 6.9 61 32.1 13.8 13.9 32 30.4 28 41.6 6.9 7.0 60 4.5 59 36.5 13.9 14.0 31 32.2 30 37.8 14.0 14.1 30 37.4 27 35.6 14.1 14.2 30 39.4 29 31.6 14.2 14.3 30 39.5 29 31.5 14.3 14.4 30 34 29 37 14.4 14.5 30 37.8 31 31.2 14.5 14.6 30 20.8 29 50.2 14.6 14.7 31 38.4 29 32.6 14.7 14.8 32 37 31 32 14.8 14.9 31 38.9 31 30.1 14.9 15.0 31 37.2 30 32.8 three phase distribution (%)water amount (mm) three phase distribution (%)s1 core depth (m) s1 core depth (m) water amount (mm) table a2. soil water content (mm) and three phase distribution (%) of 0.1 m core samples. g eo lo gi a c ro at ic a geologia croatica 71/278 gas phase liquid phase solid phase gas phase liquid phase solid phase 0.0 0.1 32 35.8 31 33.2 5.0 5.1 65 11.6 64 24.4 0.10.2 39 29 38 33 5.1 5.2 66 10.2 65 24.8 0.2 0.3 47 12.5 46 41.5 5.2 5.3 66 8.4 65 26.6 0.3 0.4 46 12 45 43 5.3 5.4 72 4.5 71 24.5 0.4 0.5 52 26.4 51 22.6 5.4 5.5 69 9.9 68 22.1 0.5 0.6 60 13.7 59 27.3 5.5 5.6 68 10.5 67 22.5 0.6 0.7 61 17.4 60 22.6 5.6 5.7 66 11.7 65 23.3 0.7 0.8 67 16.5 66 17.5 5.7 5.8 68 11.5 67 21.5 0.8 0.9 69 12.9 68 19.1 5.8 5.9 69 9.7 68 22.3 0.9 1.0 63 26 62 12 5.9 6.0 67 8.8 66 25.2 1.0 1.1 68 13.1 67 19.9 6.0 6.1 65 7.5 64 28.5 1.1 1.2 58 10.5 57 32.5 6.1 6.2 67 4.8 66 29.2 1.2 1.3 71 18.5 70 11.5 6.2 6.3 63 11.5 62 26.5 1.3 1.4 72 2.1 71 26.9 6.3 6.4 62 6.2 61 32.8 1.4 1.5 69 17.1 68 14.9 6.4 6.5 87 10.5 55 34.5 1.5 -1.6 71 18 70 12 6.5 6.6 62 4.4 61 34.6 1.6 1.7 68 16 67 17 6.6 6.7 61 3 60 37 1.7 1.8 64 28.6 63 8.4 6.7 6.8 60 4 59 37 1.8 1.9 67 12.9 66 21.1 6.8 6.9 57 4.8 56 39.2 1.9 2.0 75 5 74 21 6.9 7.0 57 7.2 56 36.8 2.0 2.1 77 6 76 18 7.0 7.1 61 0.2 60 39.8 2.1 2.2 77 5.4 76 18.6 7.1 7.2 53 1.2 52 46.8 2.2 2.3 76 4.8 75 20.2 7.2 7.3 56 6.2 55 38.8 2.3 2.4 76 5.5 75 19.5 7.3 7.4 55 3.8 54 42.2 2.4 2.5 76 6.6 75 18.4 7.4 7.5 55 6.1 54 39.9 2.5 2.6 68 17.7 67 15.3 7.5 7.6 53 7.2 52 40.8 2.6 2.7 72 2.3 71 26.7 7.6 7.7 53 14.8 52 33.2 2.7 2.8 71 10 70 20 7.7 7.8 51 6.4 50 43.6 2.8 2.9 74 11 73 16 7.8 7.9 52 3.4 51 45.6 2.9 3.0 70 14.7 69 16.3 7.9 8.0 53 1.2 52 46.8 3.0 3.1 67 5 66 29 8.0 8.1 55 0.6 54 45.4 3.1 3.2 66 2.6 65 32.4 8.1 8.2 54 1.9 53 45.1 3.2 3.3 69 18.4 68 13.6 8.2 8.3 51 4.8 50 45.2 3.3 3.4 67 13.4 66 20.6 8.3 8.4 53 2.8 52 45.2 3.4 3.5 69 6.9 68 25.1 8.4 8.5 53 4 52 44 3.5 3.6 68 17.8 67 15.2 8.5 8.6 52 3.6 51 45.4 3.6 3.7 60 7.9 59 33.1 8.6 8.7 48 5.5 47 47.5 3.7 3.8 67 2.8 66 31.2 8.7 8.8 52 3.7 51 45.3 3.8 3.9 69 6.1 68 25.9 8.8 8.9 51 3.1 50 46.9 3.9 4.0 59 17.4 58 24.6 8.9 9.0 50 3 49 48 4.0 4.1 67 5 66 29 9.0 9.1 53 0.3 52 47.7 4.1 4.2 68 2.8 67 30.2 9.1 9.2 52 1.1 51 47.9 4.2 4.3 65 2.2 64 33.8 9.2 9.3 52 2.3 51 46.7 4.3 4.4 55 8.2 54 37.8 9.3 9.4 52 2.4 51 46.6 4.4 4.5 69 3.8 68 28.2 9.4 9.5 50 5.7 49 45.3 4.5 4.6 59 4.9 58 37.1 9.5 9.6 151 7 48 45 4.6 4.7 49 6 48 46 9.6 9.7 48 7.4 47 45.6 4.7 4.8 48 14.3 47 38.7 9.7 9.8 49 5.9 48 46.1 4.8 4.9 47 22.6 46 31.4 9.8 9.9 53 1.3 52 46.7 4.9 5.0 49 24.4 48 27.6 9.9 10.0 52 4.6 51 44.4 10.0 10.1 53 2.4 52 45.6 three phase distribution (%)c3 core depth (m) water amount (mm) three phase distribution (%) c3 core depth (m) water amount (mm) table a2. continuation. g eologia c roatica okumura et al.: evaluations of the downward velocity of soil water movement in the unsaturated zone in a groundwater recharge area ... 79 gas phase liquid phase solid phase gas phase liquid phase solid phase 0.0 0.2 144 25 47 28 0.0 0.2 77 23 38 39 0.2 0.4 98 25.4 48 26.6 0.2 0.4 116 28.9 57 14.1 0.4 0.6 96 30.6 47 22.4 0.4 0.6 120 12.5 59 28.5 0.6 0.8 94 24.8 46 29.2 0.6 0.8 108 30 53 17 0.8 1.0 92 26 55 19 0.8 1.0 118 27.3 58 14.7 1.0 1.2 100 n.d. n.d. n.d. 1.0 1.2 119 n.d. n.d. n.d. 1.2 1.4 98 n.d. n.d. n.d. 1.2 1.4 126 n.d. n.d. n.d. 1.4 1.6 100 n.d. n.d. n.d. 1.4 1.6 130 11 64 25 1.6 1.8 112 n.d. n.d. n.d. 1.6 1.8 130 17.5 64 18.5 1.8 2.0 108 n.d. n.d. n.d. 1.8 2.0 132 16.5 65 18.5 2.0 2.2 100 n.d. n.d. n.d. 2.0 2.2 141 n.d. 69 n.d. 2.2 2.4 90 n.d. n.d. n.d. 2.2 2.4 149 4.7 73 22.3 2.4 2.6 77 n.d. n.d. n.d. 2.4 2.6 145 4.4 71 24.6 2.6 2.8 73 n.d. n.d. n.d. 2.6 2.8 143 2.2 70 27.8 2.8 3.0 79 n.d. n.d. n.d. 2.8 3.0 143 3.5 70 26.5 3.0 3.2 82 n.d. n.d. n.d. 3.0 3.2 139 11.4 68 20.6 3.2 3.4 84 n.d. n.d. n.d. 3.2 3.4 132 16.7 65 18.3 3.4 3.6 73 n.d. n.d. n.d. 3.4 3.6 139 9 68 23 3.6 3.8 82 n.d. n.d. n.d. 3.6 3.8 141 19.5 69 11.5 3.8 4.0 73 n.d. n.d. n.d. 3.8 4.0 135 18.5 66 15.5 4.0 4.2 96 n.d. n.d. n.d. 4.0 4.2 130 3.5 64 32.5 4.2 -4.4 63 n.d. n.d. n.d. 4.2 -4.4 124 17.5 61 21.5 4.4 4.6 128 n.d. n.d. n.d. 4.4 4.6 102 21.4 50 28.6 4.6 4.8 100 n.d. n.d. n.d. 4.6 4.8 120 11.8 59 29.2 4.8 5.0 104 16.5 55 28.5 4.8 5.0 115 n.d. 56.5 n.d. 5.0 5.2 110 17.8 52.5 29.7 5.0 5.2 110 16.9 54 29.1 5.2 5.4 102 n.d. n.d. n.d. 5.2 5.4 102 12 50 38 5.4 5.6 106 n.d. n.d. n.d. 5.4 5.6 102 11.5 50 38.5 5.6 5.8 112 n.d. n.d. n.d. 5.6 5.8 108 9.7 53 37.3 5.8 6.0 96 n.d. n.d. n.d. 5.8 6.0 105 n.d. 51.5 n.d. 6.0 6.2 104 n.d. n.d. n.d. 6.0 6.2 102 19.3 50 30.7 6.2 6.4 106 n.d. n.d. n.d. 6.2 6.4 108 2.9 53 44.1 6.4 6.6 108 n.d. n.d. n.d. 6.4 6.6 110 19 54 27 6.6 6.8 110 n.d. n.d. n.d. 6.6 6.8 104 13 51 36 6.8 7.0 106 n.d. n.d. n.d. 6.8 7.0 105 n.d. 51.5 n.d. 7.0 7.2 102 n.d. n.d. n.d. 7.0 7.2 106 12 52 36 7.2 7.4 110 n.d. n.d. n.d. 7.2 7.4 102 28 50 22 7.4 7.6 135 n.d. n.d. n.d. 7.4 7.6 104 28.7 51 20.3 7.6 7.8 118 n.d. n.d. n.d. 7.6 7.8 92 22.9 45 32.1 7.8 8.0 110 n.d. n.d. n.d. 7.8 8.0 94 n.d. 46 n.d. 8.0 8.2 122 n.d. n.d. n.d. 8.0 8.2 96 24 47 29 8.2 8.4 112 n.d. n.d. n.d. 8.2 8.4 92 23 45 32 8.4 8.6 108 n.d. n.d. n.d. 8.4 8.6 98 26.6 48 25.4 8.6 8.8 112 n.d. n.d. n.d. 8.6 8.8 100 29.1 49 21.9 8.8 9.0 108 n.d. n.d. n.d. 8.8 9.0 100 12.4 49 38.6 9.0 9.2 106 n.d. n.d. n.d. 9.0 9.2 104 18.3 51 30.7 9.2 9.4 90 n.d. n.d. n.d. 9.2 9.4 104 16 51 33 9.4 9.6 104 n.d. n.d. n.d. 9.4 9.6 104 16.5 51 32.5 9.6 9.8 100 n.d. n.d. n.d. 9.6 9.8 100 13.7 49 37.3 9.8 10.0 52 18.3 47 34.7 9.8 10.0 104 16.6 51 32.4 10.0 10.2 102 15.6 50 34.4 10.2 10.4 102 16.6 50 33.4 10.4 10.6 102 16.3 50 33.7 10.6 10.8 104 15.5 51 33.5 10.8 11.0 106 1.5 52 46.5 11.0 11.2 100 19.3 49 31.7 11.2 11.4 96 17 47 36 11.4 11.6 98 16.4 48 35.6 11.6 11.8 90 11 44 45 11.8 12.0 78 n.d. 38.5 n.d. 12.0 12.2 67 37.2 33 29.8 12.2 12.4 55 30.7 27 42.3 12.4 12.6 55 31.6 27 41.4 12.6 12.8 49 30.1 24 45.9 12.8 13.0 49 n.d. n.d. n.d. 13.0 13.2 49 31.5 24 44.5 13.2 13.4 45 30.1 22 47.9 13.4 13.6 47 30.5 23 46.5 13.6 13.8 49 31 24 45 13.8 14.0 46 n.d. n.d. n.d. 14.0 14.2 47 n.d. n.d. n.d. 14.2 14.4 43 40 21 39 14.4 14.6 49 34.2 24 41.8 14.6 14.8 46 n.d. n.d. n.d. 14.8 15.0 48 n.d. n.d. n.d. three phase distribution (%)c1 core depth (m) water amount (mm) three phase distribution (%) c2 core depth (m) water amount (mm) table a2. continuation. g eo lo gi a c ro at ic a geologia croatica 71/280 table a2. continuation. gas phase liquid phase solid phase gas phase liquid phase solid phase 0.0 0.1 51 13.9 50 36.1 7.0 7.1 45 6.7 44 49.3 0.10.2 47 9.4 46 44.6 7.1 7.2 44 2.5 43 54.5 0.2 0.3 47 27.9 46 26.1 7.2 7.3 41 9.9 40 50.1 0.3 0.4 50 19.8 49 31.2 7.3 7.4 42 18.2 41 40.8 0.4 0.5 50 22.6 49 28.4 7.4 7.5 46 6.3 45 48.7 0.5 0.6 50 36.9 49 14.1 7.5 7.6 47 10 46 44 0.6 0.7 47 21.3 46 32.7 7.6 7.7 42 18.2 41 40.8 0.7 0.8 53 25.2 52 22.8 7.7 7.8 43 1.3 42 56.7 0.8 0.9 53 28.9 52 19.1 7.8 7.9 41 11.9 40 48.1 0.9 1.0 54 29.2 53 17.8 7.9 8.0 41 15.9 40 44.1 1.0 1.1 50 34.4 49 16.6 8.0 8.1 44 18.6 43 38.4 1.1 1.2 58 14 57 29 8.1 8.2 49 4.7 48 47.3 1.2 1.3 45 35.5 44 20.5 8.2 8.3 37 9.9 36 54.1 1.3 1.4 54 8.8 53 38.2 8.3 8.4 46 16 45 39 1.4 1.5 58 17.7 57 25.3 8.4 8.5 37 21.7 36 42.3 1.5 -1.6 54 10.9 53 36.1 8.5 8.6 38 11.3 37 51.7 1.6 1.7 63 10.7 62 27.3 8.6 8.7 36 38.7 35 26.3 1.7 1.8 61 9.8 60 30.2 8.7 8.8 36 20.8 35 44.2 1.8 1.9 54 19.8 53 27.2 8.8 8.9 35 38.8 34 27.2 1.9 2.0 55 10.5 54 35.5 8.9 9.0 35 21.9 34 44.1 2.0 2.1 59 17.2 58 24.8 9.0 9.1 34 38.8 33 28.2 2.1 2.2 59 16 58 26 9.1 9.2 36 38 35 27 2.2 2.3 66 17.5 65 17.5 9.2 9.3 39 23.6 38 38.4 2.3 2.4 66 8.9 65 26.1 9.3 9.4 38 22.9 37 40.1 2.4 2.5 64 18 63 19 9.4 9.5 37 39 36 25 2.5 2.6 57 18.7 56 25.3 9.5 9.6 36 39 35 26 2.6 2.7 59 1.2 58 40.8 9.6 9.7 38 24.1 37 38.9 2.7 2.8 62 5 61 34 9.7 9.8 38 24.5 37 38.5 2.8 2.9 55 5.4 54 40.6 9.8 9.9 37 22.9 36 41.1 2.9 3.0 57 1.3 56 42.7 9.9 10.0 35 24.6 34 41.4 3.0 3.1 54 8.5 53 38.5 10.0 10.1 45 14.9 44 41.1 3.1 3.2 54 8.7 53 38.3 10.1 10.2 40 18.4 39 42.6 3.2 3.3 53 9.4 52 38.6 10.2 10.3 47 15 46 39 3.3 3.4 51 9 50 41 10.3 10.4 45 12.6 44 43.4 3.4 3.5 47 2.8 46 51.2 10.4 10.5 47 16.5 46 37.5 3.5 3.6 54 4.5 53 42.5 10.5 10.6 39 5.4 38 56.6 3.6 3.7 52 16 51 33 10.6 10.7 50 3 49 48 3.7 3.8 53 8.8 52 39.2 10.7 10.8 50 1.8 49 49.2 3.8 3.9 55 3 54 43 10.8 1.09 45 13.3 44 42.7 3.9 4.0 59 8.2 58 33.8 10.9 11.0 49 18.1 48 33.9 4.0 4.1 52 4.3 51 44.7 11.0 11.1 49 18.1 48 33.9 4.1 4.2 58 4.5 57 38.5 11.1 11.2 50 10.2 49 40.8 4.2 4.3 55 15 54 31 11.2 11.3 50 2.6 49 48.4 4.3 4.4 54 1.8 53 45.2 11.3 11.4 49 1.3 48 50.7 4.4 4.5 56 1.6 55 43.4 11.4 11.5 50 5.1 49 45.9 4.5 4.6 57 4.6 56 39.4 11.5 11.6 52 3.8 51 45.2 4.6 4.7 53 1.2 52 46.8 11.6 11.7 51 9.3 50 40.7 4.7 4.8 48 19.5 47 33.5 11.7 11.8 45 16.2 44 39.8 4.8 4.9 51 18.3 50 31.7 11.8 11.9 47 6 46 48 4.9 5.0 54 16.8 53 30.2 11.9 12.0 51 4.3 50 45.7 5.0 5.1 58 1.1 57 41.9 12.0 12.1 53 2 52 46 5.1 5.2 62 5.9 61 33.1 12.1 12.2 57 3.3 56 40.7 5.2 5.3 60 3.8 59 37.2 12.2 12.3 53 17 52 31 5.3 5.4 60 2.1 59 38.9 12.3 12.4 56 2 55 43 5.4 5.5 59 2.4 58 39.6 12.4 12.5 59 6.4 58 35.6 5.5 5.6 47 26.1 46 27.9 12.5 12.6 55 3.6 54 42.4 5.6 5.7 53 18.9 52 29.1 12.6 12.7 52 10 51 39 5.7 5.8 57 4.5 56 39.5 12.7 12.8 54 4 53 43 5.8 5.9 56 1.2 55 43.8 12.8 12.9 56 4.9 55 40.1 5.9 6.0 56 4.7 55 40.3 12. 9 -13.0 51 16 50 34 6.0 6.1 53 7 52 41 13.0 13.1 60 6.2 59 34.8 6.1 6.2 52 8.2 51 40.8 13.1 13.2 57 7 56 37 6.2 6.3 50 5.6 49 45.4 13.2 13.3 54 8.3 53 38.7 6.3 6.4 51 7 50 43 13.3 13.4 60 4.5 59 36.5 6.4 6.5 46 8.6 45 46.4 13.4 13.5 62 6.4 61 32.6 6.5 6.6 55 9.2 54 36.8 13.5 13.6 54 8.2 53 38.8 6.6 6.7 50 8.6 49 42.4 13.6 13.7 58 5.9 57 37.1 6.7 6.8 53 8.9 52 39.1 13.7 13.8 57 5.3 56 38.7 6.8 6.9 48 7 47 46 13.8 13.9 56 10 55 35 6.9 7.0 51 1.9 50 48.1 13.9 14.0 56 10.4 55 34.6 three phase distribution (%)s2 core depth (m) water amount (mm) three phase distribution (%) s2 core depth (m) water amount (mm) g eologia c roatica okumura et al.: evaluations of the downward velocity of soil water movement in the unsaturated zone in a groundwater recharge area ... 81 table a3. precipitation data using dfm calculation for all cores. total amount(mm) δd (‰) δ18o (‰) d-excess (‰) total amount(mm) δd (‰) δ18o (‰) d-excess (‰) jan-2005 5 48 -50 -9.5 26 jan-2011 3 3 -40 -8.6 28.2 feb-2005 6 100 -44 -7.6 16.8 feb-2011 8 40 -58 -10.0 21.9 mar-2005 9 128 -24 -5.1 16.8 mar-2011 8 51 -30 -6.7 23.7 apr-2005 17 92 -14 -3.2 11.6 apr-2011 15 67 -14 -4.1 18.6 may-2005 21 135 -26 -4.6 10.8 may-2011 20 126 -79 -10.3 4.2 jun-2005 26 93 -38 -5.9 9.2 jun-2011 24 929 -69 -10.0 10.8 jul-2005 28 365 -48 -7.4 11.2 jul-2011 28 253 -50 -7.4 9.4 aug-2005 28 73 -66 -9.7 11.6 aug-2011 28 385 -44 -6.6 9.0 sep-2005 27 147 -89 -11.7 4.6 sep-2011 25 76 -74 -9.8 4.8 oct-2005 21 41 -20 -4.4 15.2 oct-2011 19 107 -40 -6.8 14.0 nov-2005 14 73 -18 -4.9 21.2 nov-2011 16 89 -38 -6.9 16.6 dec-2005 5 31 -16 -6.3 34.4 dec-2011 7 33 n.d. n.d. n.d. jan-2006 6 61 -40 -6.6 12.8 jan-2012 5 15 -64 -10.1 16.6 feb-2006 8 118 -28 -5.8 18.4 feb-2012 6 32 -33 -6.3 17.5 mar-2006 10 102 -20 -4.9 19.2 mar-2012 11 90 -21 -4.2 12.0 apr-2006 15 216 -14 -3.3 12.4 apr-2012 16 42 -38 -5.8 9.1 may-2006 21 214 -21 -4.3 13.4 may-2012 21 25 -61 -7.9 2.1 jun-2006 24 642 -51 -7.8 11.4 jun-2012 23 223 -53 -7.4 6.8 jul-2006 28 789 -39 -6.1 9.8 jul-2012 28 183 -41 -6.5 11.0 aug-2006 29 428 -62 -8.6 6.8 aug-2012 29 35 -55 -8.1 9.7 sep-2006 25 94 -33 -5.9 14.2 sep-2012 25 24 -74 -10.0 5.9 oct-2006 21 11 -7 -2.6 13.8 oct-2012 19 39 -22 -5.1 18.0 nov-2006 15 81 -56 -8.9 15.2 nov-2012 12 21 -35 -7.0 21.3 dec-2006 9 48 -42 -7.4 17.2 dec-2012 6 14 -16 -4.9 24.0 jan-2007 7 34 0 -3.3 26.4 jan-2013 5 45 -96 -13.3 10.9 feb-2007 10 76 -16 -4.7 21.6 feb-2013 7 167 -23 -5.5 20.7 mar-2007 12 105 -20 -4.7 17.6 mar-2013 12 110 -17 -4.0 15.8 apr-2007 15 109 -38 -6.4 13.2 apr-2013 15 164 -19 -4.4 15.8 may-2007 21 141 -31 -5.2 10.6 may-2013 21 54 -30 -4.8 8.2 jun-2007 24 184 -63 -8.7 6.6 jun-2013 24 308 -57 -8.5 10.6 jul-2007 27 675 -67 -9 5 jul-2013 29 119 -38 -6.2 11.8 aug-2007 29 176 -43 -5.7 2.6 aug-2013 29 571 -52 -7.8 11.0 sep-2007 27 81 -30 -4.9 9.2 sep-2013 25 199 -89 -12.7 12.7 oct-2007 21 135 n.d. n.d. n.d. oct-2013 21 109 -43 -6.6 9.1 nov-2007 13 31 -27 -6.9 28.2 nov-2013 12 80 -35 -6.7 18.8 dec-2007 9 67 -25 -5.6 19.8 dec-2013 7 51 -68 -10.1 13.1 jan-2008 7 137 n.d. n.d. n.d. jan-2014 6 36 -18 -5.4 25.5 feb-2008 5 44 n.d. n.d. n.d. feb-2014 7 121 -41 -7.5 19.0 mar-2008 11 91 n.d. n.d. n.d. mar-2014 11 130 -35 -6.1 13.2 apr-2008 16 116 -42 -6.7 11.8 apr-2014 16 69 -14 -3.5 14.5 may-2008 20 210 -54 -7.1 2.8 may-2014 20 135 -50 -7.4 9.1 jun-2008 23 776 -66 -9.1 6.7 jun-2014 23 259 -84 -11.3 6.6 jul-2008 29 204 -67 -9.2 7.2 jul-2014 27 358 -31 -4.4 4.6 aug-2008 28 227 -53 -7.9 10.7 aug-2014 27 213 -48 -7.4 11.0 sep-2008 26 295 -79 -11.2 10.4 sep-2014 24 107 -52 -7.9 11.5 oct-2008 20 62 -9 -5.1 32.4 oct-2014 20 142 -29 -5.3 13.8 nov-2008 13 89 -11 -8.2 54.9 nov-2014 14 63 -40 -7.1 16.7 dec-2008 8 106 -11 -3.6 17.8 dec-2014 6 63 -23 -6.6 29.4 jan-2009 6 55 -21 -5.4 21.8 jan-2015 7 100 -31 -6.1 17.6 feb-2009 10 134 -15 -4.3 18.8 feb-2015 7 34 -21 -5.3 21.0 mar-2009 11 145 -32 -5.4 11.9 mar-2015 11 186 -23 -5.7 22.2 apr-2009 16 80 -42 -6.8 13.2 apr-2015 17 151 -11 -2.9 11.8 may-2009 21 69 -37 -5.3 5.6 may-2015 21 131 -36 -5.7 9.7 jun-2009 24 246 -45 -6.7 8.9 jun-2015 22 628 -39 -6.4 11.8 jul-2009 27 429 -53 -7.8 10.1 jul-2015 26 376 -53 -8.0 10.8 aug-2009 29 67 -53 -7.1 4.2 aug-2015 27 246 -61 -8.6 8.1 sep-2009 26 34 -27 -4.7 10.6 sep-2015 24 150 -64 -9.2 9.5 oct-2009 19 130 -35 -5.0 5.2 oct-2015 19 65 -70 -10.0 10.2 nov-2009 13 112 -69 -10.2 12.1 nov-2015 16 137 2 -2.7 22.9 dec-2009 8 67 -44 -7.9 19.4 dec-2015 10 92 -49 -8.2 16.2 jan-2010 6 48 -25 -5.3 17.2 jan-2016 6 71 -20 -5.0 19.7 feb-2010 10 192 -25 -4.6 12.0 feb-2016 7 74 -64 -10.3 18.3 mar-2010 11 177 -25 -6.7 29.1 mar-2016 11 60 -35 -7.2 22.8 apr-2010 15 226 -27 -4.5 8.5 apr-2016 17 179 -47 -8.3 19.7 may-2010 20 285 -29 -4.6 8.2 may-2016 21 273 -37 -7.1 20.6 jun-2010 24 401 -85 -11.6 7.9 jun-2016 24 644 -5 -2.5 15.1 jul-2010 27 362 -42 -6.0 5.9 jul-2016 28 390 -19 -3.8 11.6 aug-2010 30 58 -43 -5.5 1.3 sep-2010 26 118 -43 -6.5 9.2 oct-2010 20 85 -40 -6.7 13.3 nov-2010 12 29 -34 -7.2 22.9 dec-2010 8 94 -40 -7.7 21.1 month month average temperature (℃) precipitationprecipitationaverage temperature (℃) g eo lo gi a c ro at ic a geologia croatica 71/282 www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2025 | 78/2 | 151–172 | 4 figs. | 8 tabs. | 1. introduction the geochemical atlas of croatia (gac) provides insights into regional and local topsoil geochemistry and indicates the importance of further research (halamić & miko, 2009). the collected data of the gac was stored in the geographic information software (gis) database and therefore offers a possi bility of comparison with other databases that contain the same type of data. therefore, the various influences on the geochemistry of the topsoil could be analysed. the regional variability of the natural geochemical background is also bet­ ter known, allowing better understanding and identification of anthropogenic influences. the total number of sampling points for gac in topsoil across croatia was 2,521, sampled in a re­ gu lar grid of 5 x 5 km. based on the results obtained, individual maps for 27 chemical elements were generated. all elements showed differences in the spatial distribution of two geo dyna­ mic units in croatia to some extent: dinaric­coastal (din) and pannonian basin (pan). hasan et al. (2020) elaborated on the geochemical signature by geology, soil, land use and land cover and region in din. it is sufficient to highlight here that 1,254 topsoil samples were collected to explore the factors behind the characteristic geochemical signature of the pannonian basin. this was done using different environmental and geological criteria that were, by default, independent of the soil geochemistry and geochemical map of croatia – key findings and legacy of geochemical mapping in the pannonian basin ajka pjanić1, josip halamić1, lidija galović1*, zoran peh1 1 croatian geological survey, sachsova 2, 10 000 zagreb, croatia; (*corresponding author: lgalovic@hgi-cgs.hr; apjanic@hgi-cgs.hr; jhalamic@hgi-cgs.hr; zpeh@hgi-cgs.hr) doi: 10.4154/gc.2025.08 abstract the geochemical atlas of croatia revealed differences in the spatial distribution of geochemical elements between the croatian dinaric coastal region and the pannonian basin. in the pannonian basin, 1,254 topsoil samples (0–25 cm) were analysed for 27 elements and ph values. this geodynamic unit is characterised by the variability of geological, pedological and land-use-related characteristics. to analyse the geochemical properties of soil above different lithological units, soil types and land use and land cover classes, a discriminant function analysis was performed using the compositional data. the study shows significant geochemical and ecological patterns, with the first two discriminant functions explaining a major proportion of the variability: in the geology model, df1 explains 33.31% and df2 17.97%; in the soil model, df1 explains 51.59% and df2 20.22%; in the clc model df1 explains 59.85% and df2 30.30%. the geological model distinguishes between the quaternary sediments and the older lithological units and highlights alkaline and acidic soil conditions. the soil model shows the effects of fluvial and alluvial deposits, agricultural practices and the underlying geology on soil composition and emphasises the enrichment of essential nutrients and heavy metals in the soils. the land use and land cover model illustrates the anthropogenic influence on agricultural soils and the susceptibility of wetlands to heavy metal accumulation. the results obtained illustrate the complex interaction between geology, the topsoil layer, as well as land use and land cover, providing awareness for environmental management and monitoring, and the need for further geochemical studies of the soils in the pannonian basin. involved such divisions as surface geology at the sampling point, various soil types, and descriptions of the land use. the latter was borrowed from the land cover classes described in the corine land cover (clc; corine land cover, 2018). in contrast to the earlier investigated dinaric region, no region model was created for pan due to the homogeneity of the sub­regions within the pannonian basin. thus, three divisions – geology, soil and clc – were established, providing the most effective ways of an a priori arrangement of the soil samples into many comprehensible and all­ embracing statistical groups. in the final analysis, discriminant function analysis (dfa) was employed as a method of data reduction and structuring, generating the respective models based on geochemical partitioning between the established groups. being mathematical (statistical) by their nature, these models created appropriate structural patterns that helped explain the behaviour of the observed geochemical data in the process­form terms (strahler, 1980), most thoroughly via the geochemical maps generated in gis. the pannonian basin is characterised by a continental, moderately warm and humid climate (filipčić, 2023). the older rocks in the basin are more strongly eroded, and we do not find many of their outcrops on the surface. the basin consists mainly of quaternary formations, including loess, article history: manuscript received: july 12, 2024 revised manuscript accepted: march 5, 2025 available online: june 30, 2025 keywords: geochemical mapping, geology, fao, corine, discriminant function analysis, compositional data, pannonian basin, croatia mailto:lgalovic@hgi-cgs.hr mailto:apjanic@hgi-cgs.hr mailto:jhalamic@hgi-cgs.hr mailto:zpeh@hgi-cgs.hr g eo lo gi a c ro at ic a 152 geologia croatica 78/2 aeolian sands, alluvium, lake and swamp sediments, which overlie the older rock formations (hgi­cgs, 2009). the pedological composition of the pannonian basin in croatia is heterogeneous, which is due, among other factors, to considerable differences in subsurface lithology, climate, agricultural production, land use and water saturation (bogunović et al., 1998; bašić et al., 2007; bašić, 2013). the corine land cover dataset provides detailed infor­ mation on land use and land cover (corine land cover, 2018). this dataset offers insight into various land cover features such as forests, grasslands, wetlands, urban areas and water bodies. the clc is used in spatial data studies for the management of environmental and urban areas and natural resources, among others. the gac dataset, which includes 28 variables of topsoil, was analysed using the multivariate statistical method of dfa to study the soil geochemistry. the soil geochemical data were treated as compositional data (coda). discriminant function analysis was used in these studies as a robust statistical approach to explore the various factors responsible for different soil geochemical compositions between diverse lithologies, soil types and clc classes (aitchison, 1986). furthermore, con sistent geochemical maps were created using gis to visua­ lise the spatial relationships between the models. the main objec tive of the study, based on the dfa results, was to investi­ gate relationships between the groups within these three models, i.e. underlying geology, soil and land use and land cover. 2. materials and methods 2.1. study area the republic of croatia is geographically located in central and southeast europe, between the latitudes 42° n and 47° n, and longitudes 13° e and 20° e. it covers an area between the central danube basin and the central mediterranean and serves as a bridge between central and eastern europe and the mediterranean (fig. 1). geomorphologically, croatia can be divided into three different regions, each of which has characteristic climatic and hydrological features: the pannonian basin (the northern part), the mountainous region (mostly the central part) and the adriatic coast (mostly the southern part). the pannonian basin features a continental climate with varied atmospheric conditions. filipčić (2023) applied the climate regionalisation by köppen (1918) to croatia, covering the interval 1961–1990. the pannonian basin is assigned to the cfb region (c – temperate, f – no dry season, b – warm summer). the average temperature in july is 20–22 °c, while the average temperature in january is 0 °c to –3 °c. the amount of precipitation in this area shows a gradient that decreases from the western part of the pannonian basin with 1,000–1,100 mm into the central part with 700 to 1,000 mm and to the easternmost part, which is drier with 300 to 700 mm (zaninović et al., 2008). 2.1.1. geological settings the area of northern and northwestern croatia geotectonically belongs to the area of the southwestern pannonian basin. during the long geological history of northern croatia (documented over 600 million years), the oldest rocks passed through many orogenic cycles and large proportions of them have been lost (either subducted and/or eroded), so that today we have relatively few surface outcrops of these oldest rocks from the proterozoic and palaeozoic (fig. 2a, b; table 1). furthermore, a large part of northern croatia (about 60%) is covered by the youngest, quaternary formations (loess, figure 1. geographic location of the study area of the pannonian basin, croatia. g eologia c roatica 153pjanić et al.: geochemical map of croatia – key findings and legacy of geochemical mapping in the pannonian basin figure 2. a) geological map (hgi-cgs, 2009); b) the map showing the geological criterion (geo code); c) pedological map (bogunović, 1998); d) the map showing the soil criterion (fao code); e) land use and land cover map (corine land cover, 2018) and f) the map showing land use and land cover criterion (clc code) of the study area in pannonian basin, croatia. the dots in the maps show that geo, fao and clc are also locations of the sampling sites. g eo lo gi a c ro at ic a 154 geologia croatica 78/2 aeolian sands, alluvial, lake and marsh sediments) so that older rocks emerge from beneath this young cover as the so­called “inselgebirge” (velić & vlahović, 2009). the oldest rocks in that area are proterozoic (neopro tero­ zoic) metamorphic rocks, and they are observed on the psunj and krndija mts. the main mass of these rocks consists of various types of paragneisses and orthogneisses, and their source rocks were volcanogenic­sedimentary formations. these rocks were metamorphosed, ranging from chlorite to epidote­amphibolite facies, between 650–550 million years table 1. legend of the geological map of the pannonian basin (from the geological map of the republic of croatia, scale 1:300,000) (hgi-cgs, 2009). lithostratigraphic unit group according to grouping criterianumber of unit name 58a deluvial-proluvial deposits (holocene) geo12 58b alluvial deposits (holocene) geo13 57b marsh deposits (holocene) geo10 56 aeolian sands (holocene) geo11 54a terrestrial loess (pleistocene) geo10 54b marsh loess (pleistocene) geo10 53a fluvial deposits (pleistocene) geo13 52 plioquaternary clastic deposits geo9 50 paludina beds (zanclean, piacenzian) geo9 49 sands and clays (pliocene) geo9 48 clastic sediments and coal (pannonian) geo9 47 limestone-clastic sediments (sarmatian, pannonian) geo8 46 lithothamnium limestone and clastic deposits with volcanics (badenian) geo8 45a magmatic rocks (karpatian, badenian): andesites * 45b magmatic rocks (karpatian, badenian): basalts * 44 clastic and carbonates with clastic (ottnangian, karpatian) geo7 43 clastic with volcanic sediments (egerian, eggenburgian) geo7 38 carbonate flysch and clastic (palaeocene, eocene) geo6 37a magmatic rocks (upper cretaceous – palaeogene): basalts * 37b magmatic rocks (upper cretaceous): rhyolites * 37c magmatic rocks (upper cretaceous): granites * 36 carbonate clastic (mainly flysch) and “scagalia” limestones (upper cretaceous) geo6 35 hemipelagic and turbidite deposits (lower cretaceous) geo6 34 rudists limestons (cenomanian, maastrichtian) geo6 32 parametamorphic rocks (middle jurassic) * 31a ophiolite rocks (middle, upper jurassic): ultramafites geo2 31b ophiolite rocks (middle, upper jurassic): magmatites geo2 31c ophiolite rocks (middle, upper jurassic): sediment rocks geo2 30 parametamorphic rocks (middle jurassic) geo2 29 orthometamorphic rocks (middle jurassic) geo2 28 calpionellid limestones with cherts (tithonian, berriasian) * 27 platy limestones (jurassic in general) * 25 forereef and reef limestones and dolomites (kimmeridgian, tithonian) * 20 dolomites (upper norian, rhaetian) geo5 17a magmatic rocks: andesites and basalts (middle and upper triassic) geo2 16 clastic and pyroclastic deposits (middle triassic) geo5 15 carbonate sediments (middle triassic) geo5 14 induanian and olenekian deposits (lower triassic) geo4 13b evaporites and clastic deposits (upper permian): clastic geo4 12 magmatites (?permian) * 11 granites (permian) * 10 predominantly clastic deposits (carboniferous, permian) geo3 8 hercynian semimetamorphic complex (devonian, carboniferous, permian) geo3 7 clastic and carbonate sediments (devonian, carboniferous) geo3 6 parametamorphites (palaeozoic, triassic) geo3 5 orthometamorphites (palaeozoic, triassic) geo2 4 granitic rocks (ordovician, silurian, devonian) geo1 3 complex of metamorphic rocks (ordovician, silurian, devonian) geo1 2 progressive metamorphic series (ordovician, silurian, devonian) geo1 1 complex of metamorphic rocks (precambrian) geo1 *no sampling sites in these units g eologia c roatica 155pjanić et al.: geochemical map of croatia – key findings and legacy of geochemical mapping in the pannonian basin ago (jamičić & crnko, 2009). since then, there have been no documented rock records in the research area for about another 100 million years. the oldest rocks of the early palaeozoic belong to the or­ dovician. these rocks comprise migmatite gneisses, biotite­ and biotite­muscovite gneisses, mica schists, granitoid rocks, chlorite schists, amphibolites and amphibole schists, pegma­ tites and aplites, peridotites and serpentinites, which are found in the eastern and central parts of papuk mt., in the area of ravna gora mt. and the western part of krndija mt. the larg­ est part of this complex represents a progressive metamorphic series (pamić & lanphere, 1991), meaning that all tran­ sitions from low to medium metamorphic varieties (chlorite to amphibolite facies) can be found in the terrain. rocks belonging to the younger palaeozoic can be found on the medvednica, trgovska gora, papuk, and psunj mts. and to a lesser extent on the žumberak and ivanščica mts. they consist of mostly non­metamorphic to low­metamorphic rocks (slates, slate phyllites, marbles, quartz sericite and quartz chlorite schists). mesozoic rocks (triassic and jurassic) can be observed on almost all the mountains of northern croatia (ivanščica, kalnik, medvednica, žumberak, trgovska gora, psunj and papuk mts.). they are composed of sedimentary rocks depos­ ited, initially in continental environments (mainly clastites – lower triassic), and after deepening of the sedimentary basin, on a carbonate platform (limestones and dolomites – middle triassic to middle jurassic). contemporaneously, in the deeper parts of the ocean space, during the middle and upper trias­ sic and the lower and middle jurassic, rocks of the ophiolitic complex were formed, namely: ultrabasic rocks (peridotites), gabbros, amphibolites, diabases, and pillow lavas, which are interstratified with deep­sea siliceous radiolarian muds. the belt containing these rocks extends from the town of dvor, through the southwestern parts of zrinska gora mt. and the north­western parts of trgovska gora mt., continuing at a depth of about 800 m below the vukomeričke gorice hills (hgi­cgs, 1992) to the se part of the samoborska gora mt., and across the nw part of medvednica mt. and the se part of the ivanščica and kalnik mts., continuing towards the north­ east into hungary (fig. 2a, b; table 1). after the closure of the oceanic domain (due to subduc­ tion) from the late jurassic to the early cretaceous, foreland and piggyback basins were formed, and material eroded from the rising parts of the newly emerging land was deposited in them. outcrops of these rocks can be found on the trgovska and zrinska gora mts. in banovina province, then on the žumberak, medvednica, kalnik and ivanščica mts., mostly in the area of the distribution belt of ophiolite rocks. this is fol­ lowed by the intrusion of the moslavačka gora granite into the ordovician granitoid crust, built mainly of muscovite and bio­ tite in different proportions, feldspar and quartz, and belongs to two­mica s­type granite (starijaš et al., 2010). transgressive conglomerates, siliciclastic and carbonate sandstones and scaglia limestones were deposited in the sed­ imentary basin formed in the upper cretaceous. sedimenta­ tion continued with carbonate turbidites until the palaeocene. in northern croatia, during formation of the paratethys (eocene–oligocene), two sedimentary basins developed, the hrvatsko zagorje basin and the northern croatian basin (pavelić & kovačić, 2018), in which sediments were first deposited in terrestrial and freshwater environments, and then, in the middle miocene, the sedimentation conditions changed and lithothamnium limestones were deposited, so that the younger deposits up to the quaternary gradually change from carbonates to poorly consolidated clastic deposits (siltites, sands, fine­grained conglomerates) (fig. 2a, b; table 1). a large part of the central area of northern croatia is cov­ ered by loess of pleistocene age (sandy clayey silt, fine­grained sand, silty clay, sandy clay) and marsh loess (clayey sandy silt). the mineral composition indicates its origin from the alps (mutić, 1975). the youngest sediments (holocene) consist of deluvial­proluvial deposits (silts, sands and gravels), marsh sediments (clays, silts, peat) and alluvial deposits (clays, silts, sands and gravels). 2.1.2. soil the pedological composition of the pannonian basin in croatia is heterogeneous due to considerable differences in the mineral composition of the subsoil, relief and water saturation. the fao unesco pedological map of croatia contains 32 pedological cartographic units, as well as urban (cities) and aquatic regions (fig. 2c, d; table 2; bogunović et al., 1998). bašić et al. (2007) have delineated three primary agricultural regions within the croatian agrosphere, each distinguished by unique climatic conditions and other characteristics: the pannonian, the mountainous and the adriatic regions, which in turn are subdivided into several subregions. the pannonian region comprises the eastern, central, western and northwest subregions. the eastern part of the pannonian region includes baranja and eastern slavonia, located in the easternmost part of croatia (fig. 2c, d; table 2). this area, where loess deposits predominate, favours the formation of very fertile soils such as chernozem, cambisol eutric and regosol. the central pannonian subregion, which includes western slavonia, podravina, bilogora and central posavina, is characterised by the predominance of hydromorphic soils. stagnosols and gleysols are the most widespread, followed by luvisol on loess, cambisol eutric, leptosol on marl and fluvisols. the western subregion, which lies on the westernmost edge of the pannonian basin plain, includes the extensive urban area of zagreb. the predominant soil types include luvisol on loess and stagno­gley, fluvisol along the drava river and gleysols. there are also eutric cambisol on loess and leptosol on marl and soft limestone. finally, the northwestern subregion comprises the north­west of croatia, in particular the areas of zagorje, varaždin and međimurje. due to the heterogeneity of the parent material and the different topography, this subregion has a variety of soil types. in the numerous valleys formed by rivers and streams, gleysols predominate, followed by leptosols on marl, stagnosols and humo fluvisols, as well as regosols and technogenic soils. technogenic soil is the pedological term used for anthropogenically influenced soils in urban areas (bogunović et al., 1998). g eo lo gi a c ro at ic a 156 geologia croatica 78/2 table 2. legend of the fao unesco pedological map of the republic of croatia, scale 1,000,000 of pannonian basin (bogunović et al., 1998). number of unit dominant unit other units group according to grouping criteria 1 mollic and calcaric fluvisols (flm+flc) mollic glaysols (glm) fl 2 eutric, mollic and calcic glaysols (gle+glm+glk) gleyic and stagnic podzoluvisols (pdg+pdj) mollic fluvisols (flm) calcaric fluvisols (flc) calcaric regosols (rgc) gl 3 eutric and calcic gleysols (gle+glk) fibric histosols (hsf) gl 4 mollic gleysols (glm) eutric gleysols (gle) gleyic and stagnic podzoluvisols (pdg+pdj) gl 5 calcaric regosols (rgc) lithic leptosols (lpq) rendzic leptosols (lpk) chromic cambisols (cmx) mollic leptosols (lpm) gl 6 calcaric regosols (rgc) calcic gleysols (glk) calcic chernozems (chk) gl 7 lithic leptosols (lpq) mollic leptosols (lpm) rendzic leptosols (lpk) chromic cambisols (cmx) lp 8 rendzic leptosols (lpk) aric anthrosols (ata) calcaric regosols (rgc) calcic gleysols (glk) stagnic podzoluvisols (pdj) lp 9 rendzic and mollic leptosols (lpk+lpm) chromic cambisols (cmx) chromic luvisols (lvx) aric anthrosols (ata) lp 10 mollic leptosols (lpm) chromic cambisols (cmx) rendzic leptosols (lpk) chromic luvisols (lvx) lp 11 umbric and dystric leptosols (lpu+lpd) dystric cambisols (cmd) cambic podzols (pzb) lp 12 calcaric and cambic arenosols (arc+arb) calcic luvisols (lvk) stagnic podzoluvisols (pdj) dystrict cambisols (cmd) mollic and eutric leptosols (lpm+lpe) * 13 eutric and calcic vertisols (vre+vrk) rendzic leptosols (lpk) calcaric regosols (rgc) chromic cambisols (cmx) * 14 eutric cambisols (cme) calcic chernozems (chk) aric anthrosols (ata) cm 15 eutric cambisols (cme) albic luvisols (lva) mollic fluvisols (flm) eutric gleysols (gle) aric anthrosols (ata) cm 16 eutric and dystric cambisols (cme+cmd) eutric and umbric leptosols (lpe+lpu) albic luvisols (lva) stagnic podzoluvisols (pdj) eutric gleysols (gle) calcaric and eutric regosols (rgc+rge) cm 17 dystric and humic cambisols (cmd+cmu) cambic and haplic podzols (pzb+pzh) umbric leptosols (lpu) cm 18 humic and dystric cambisols (cmu+cmd) umbric leptosols (lpu) haplic lixisols (lxh) cm 19 chromic cambisols (cmx) chromic luvisols (lvx) rendzic and mollic leptosols (lpk+lpm) aric anthrosols (ata) eutric cambisols (cme) cm 20 calcic chernozems (chk) eutric cambisols (cme) ch 21 gleyic and calcic chernozems (chg+chk) mollic gleysolls (glm) ch 22 albic luvisols (lva) rendzic and mollic leptosols (lpk+lpm) lv 23 albic and gleyic luvisols (lva+lvg) stagnic podzoluvisols (pdj) eutric, dystrict and calcaric cambisols (cme+cmd+cmc) stagnic lixisols (lxj) cambic and calcaric arenosols (arb+arc) lv g eologia c roatica 157pjanić et al.: geochemical map of croatia – key findings and legacy of geochemical mapping in the pannonian basin 2.1.3. corine land cover corine (coordination of information on the environment) is part of the copernicus land monitoring service (corine land cover, 2018). the main technical parameters for corine land cover mapping are the use of a minimum mapping unit of 25 hectares, a minimum width of the linear elements of 100 metres, geometric accuracy of the clc data of more than 100 m and a thematic accuracy of ≥ 85%. the standard clc nomenclature comprises 44 land cover classes. these are grouped in a three­level hierarchy. level 1 consists of five main categories: 1) artificial surfaces, 2) agricultural areas, 3) forests and semi­natural areas, 4) wetlands, and 5) water bodies. at levels 2 and 3, the main categories were subdivided into more detailed classes (fig. 2e, f; table 3). 2.2. sampling and sample preparation sampling of the topsoil was carried out based on the systematic sampling plan according to iso 10381­1 (iso, 2002a) and iso 10381­2 (iso, 2002b). the locations of the sampling points and the sampling density throughout the republic of croatia were determined by laying out regular square cells with an area of 25 km2 (fig. 2b, d, f). five subsamples (0–25 cm depth) were taken from the centres and corners of these cells of ≈400 m² (up to 15% deviation allowed). these were composite samples totalling 3–5 kg stored in pvc bags. the samples were air dried, sieved to a fraction of < 0.063 mm and homogenised in an agate mortar. according to the protocol (halamić et al., 2000), the sampling documentation included field observations and administrative details (sample number, soil type, coordinates, altitude, images of the surroundings, date of sampling) as well as field observations (vegetation, contaminants, relief, depth of soil profile, colour, texture, subsoil lithology), which contribute to the database of the digital geochemical atlas of croatia. 2.3. laboratory analyses and quality control the homogenized soil samples were dissolved in a mixture of four acids hf­hcl­hno3­hclo4. the solutions were analysed by inductively coupled plasma mass spectroscopy using a perkin elmer elan 6000 or 9000 acme analytical laboratories (now bureau veritas mineral laboratories), vancouver, canada (acme, 2007) for a range of 41 elements (ag, al, as, au, ba, be, bi, ca, cd, ce, co, cr, cu, fe, hf, k, la, li, mg, mn, mo, na, nb, ni, p, pb, rb, s, sb, sc, sn, sr, ta, th, ti, u, v, w, y, zn, and zr). mercury analysis was performed using aqua regia extraction by flameless atomic adsorption spectrometry (faas). analytical precision was checked by duplicate analyses of both certified reference samples and randomly selected soil samples (every 20th sample in the batch), resulting in an average coefficient of variation of approximately 5%. accuracy was checked with certified geological reference materials, i.e., gxr­2 and gxr­5 (acme labs.), and sjs­1 (usgs). the accuracy of most elements analysed in the reference soils was within ± 10% of the certified values (halamić & miko, 2009). 2.4. data processing a geochemical database of the geochemical, geological, pedological and other relevant data was created in the gis software esri® arcgis™ 10.2.1. number of unit dominant unit other units group according to grouping criteria 24 chromic luvisols (lvx) chromic cambisols (cmx) mollic leptosols (lpm) dystrict cambisols (cmd) albic lixisols (lxa) lv 25 stagnic and gleyic podzoluvisols (pdj+pdg) eutric cambisols (cme) albic and stagnic luvisols (lva+lvj) eutric and mollic gleysols (gle+flm) dystrict cambisols (cmd) pz 26 cambic podzols (pzb) humic cambisols (cmu) haplic podzols (pzh) umbric leptosols (lpu) pz 27 haplic and cambic podzols (pzh+pzb) humic cambisols (cmu) umbric leptosols (lpu) pz 28 humic acrisols (acu) chromic cambisols (cmx) rendzic leptosols (lpk) dystrict cambisols (cmd) * 29 fibric and terric histosols (hsf+hss) calcic and mollic gleysols (glk+glm) * 30 aric anthrosols (ata) cumulic anthrosols (atc) urb 31 mollic gleysols (glm) gleyic solonchaks (scg) gl 32 gleyic and albic luvisols (lvg+lva) stagnic and glayic solonetz (snj+sng) calcic solonetz (snk) * 33 urban areas – urb 34 water surfaces (lakes, ponds, sea) – *no sampling sites in this unit g eo lo gi a c ro at ic a 158 geologia croatica 78/2 2.4.1. statistical processing 2.4.1.1. compositional data and log-ratio analysis the analysed dataset is composed of 28 variables exploited consistently in various earlier investigations pursuing the low­ density soil sampling during the geochemical baseline mapping in croatia (e.g., miko et al., 2001; peh et al., 2010; halamić et al., 2012). it includes al, as, ba, ca, co, cr, cu, fe, hg, k, la, mg, mn, na, nb, ni, p, pb, sc, sn, sr, th, ti, v, y, zn, zr, together with ph as the measure of soil acidity. this element suite represents the input data (explanatory variables) in discriminant function analysis used to study the impact of various soil­forming factors in the pan part of croatia. descriptive statistics for the entire dataset (min, max, mean and median) are shown in table 4 indicating, albeit, information that is proper for comparison purposes only, because the data displayed therein represent relative instead of absolute values. namely, a well­known fact that soil geochemical data represent a summary of compositional data categorically interferes with their use in the raw (compositional) form in any statistical analysis (egozcue & pawlowsky­ glahn, 2006). by its very nature, coda involves the mathematical particularity that all variables (parts) in each case (analysed sample) must be positive, confined to a constant sum a priori specified as 100%, 106 mg/kg, or 1.0. on account of this unit­sum constraint, coda can be genuinely displayed only in a limited sample space (compositional space) also named simplex, composed of d parts or components (geochemical variables). thus, a suite of d­part composition (sd) fills a restricted part (between null and 100%) of a d­dimensional real space (rd), building a subset of its vectors (pawlowsky­glahn & egozcue, 2006; buccianti, 2013; buccianti & grunsky, 2014). the philosophy of the simplex as the regular sample space to inhabit coda is articulated with the following algorithm (pawlowsky­ glahn et al., 2007; buccianti, 2013): sd = x x x x x x i d xd i i d i= ( ) > ( = ) ={ }=∑1 2 3 1 0 1 2 3, , ,..., : , , ,..., , (1) where x is a constraint­sum constant; x1, x2, x3, . . ., xd are components of the composition x; and 1, 2, 3, . . . , d are parts of the composition x. simplex can be “unfolded” into the structure of the euclidean vector space only after a suitable transformation of its components. one of the several transformations normally exploited in coda analysis is the centred log ratio (clr) of the raw (compositional) data. originally introduced by aitchison (1986), this transformation is extensively utilised in multivariate statistics, including this study. the application of clr coefficients is considered of crucial importance in multivariate analyses such as dfa, since it maintains the table 3. legend of corine land cover 2012 (corine land cover, 2018) raster data of the pannonian basin (european environment agency). level 1 clc2018 description level 2 clc2018 description group according to grouping criteria 1 artificial surfaces 111 continuous urban fabric * 112 discontinuous urban fabric arts 121 industrial or commercial units arts 122 road and rail networks and associated land * 123 port areas * 124 airports * 131 mineral extraction sites * 132 dump sites * 133 construction sites * 141 green urban areas * 142 sport and leisure facilities arts 2 agricultural areas 211 non-irrigated arable land agrs 212 permanently irrigated land agrs 221 vineyards agrs 222 fruit trees and berry plantations agrs 231 pastures agrs 242 complex cultivation patterns agrs 243 land principally occupied by agriculture, with significant areas of natural vegetation agrs 3 forest and seminatural areas 311 broad-leaved forest fsna 312 coniferous forest fsna 313 mixed forest fsna 321 natural grasslands fsna 324 transitional woodland-shrub fsna 331 beaches, dunes, sands * 4 wetlands 411 inland marshes wetl 5 water bodies 511 watercourses wetl 512 water bodies wetl *no sampling sites in this unit g eologia c roatica 159pjanić et al.: geochemical map of croatia – key findings and legacy of geochemical mapping in the pannonian basin original distances between the corresponding components (egozcue & pawlowsky­glahn, 2006; tolosana­ delgado, 2012). the common problem of singularity, intrinsic to the clr­transformed covariance matrix, can be easily circumvented because dfa operates with the reduced data matrix, not contingent upon the full rank covariance matrix (daunis­i­estadella et al., 2011). actually, by the scale invariance property of the log­ratio approach, more coherent results are obtained in the case when only a subset of the variables (sub­composition) instead of full composition is used in the analysis (mert et al., 2018), a procedure involving exclusion of one composition (variable) after transformation. given that clr­transformed data assume the role of unconstrained actual vectors in the real (euclidean) space, the mahalanobis distances (md) between cases and groups remain invariant irrespective of which component is removed from the analysis (barceló­vidal et al., 1999). the clr­coefficients can be calculated from the following expression: clr x x g x x g x x g x x g x d( ) ln ( ) , ln ( ) , ln ( ) ,..., ln ( ) =     1 2 3 (2) where x1, x2, x3, . . ., xd are parts (compositions) of x, while g(x) represents their geometric mean. note that the clr coefficients are computed by dividing each component (such as the geochemical percentage, or mg/ kg) by the geometric mean of all components involved in the analysis and obtaining their logarithm in the last analysis (aitchison, 1986), as displayed in equation (2). the clr­ transformed variables represent dimensionless numbers (ratios) unsuitable for direct cross­comparison, functioning simply as input data for dfa. the quality explained above adheres to the logic of the log­ratio approach itself, substantiating further communication about the algebraic­geometric structure of the sample space. this is important for a better understanding of the results of the dfa presented in this study, especially in explaining why separate (variable and sample) scatterplots are used instead of biplots. as elucidated by aitchison & egozcue (2005) and described in galović & peh (2016), compositional parts have a twofold nature: they can be portrayed both as raw compositional data such as percentages (or mg/kg) of geochemical compositions, using vectors of parts and as coordinates (scalars) in the cartesian (orthonormal) coordinate system with euclidean metrics. in the log­ratio approach, they are not considered as simple conversions of the original data into their logarithms for data normalization, but as coordinates. seen in this light, straightforward transposition of the original data (raw compositions) to coordinate scatterplots or biplots can easily produce erroneous interpretations. one of the most tenacious fallacies that sometimes favours the application of classical (non­compositional) statistical methods table 4. descriptive statistics for raw (compositional) geochemical data. min q1 med q3 max mad g al (%) 1.46 5.79 6.41 7.20 11.81 0.71 6.45 as (mg/kg) 0.50 6.00 9.00 12.00 92.00 3.00 8.10 ba (mg/kg) 58.00 366.00 403.00 451.00 3300.00 40.00 406.33 ca (%) 0.07 0.48 0.72 1.41 26.79 0.31 0.94 co (mg/kg) 3.00 8.00 10.00 13.00 36.00 2.00 10.56 cr (mg/kg) 28.00 63.00 75.00 92.00 524.00 13.35 77.48 cu (mg/kg) 3.00 14.10 19.05 28.20 248.00 6.05 19.89 fe (%) 0.60 2.60 2.99 3.56 6.81 0.46 3.05 hg (μg/kg) 5.00 30.00 40.00 65.00 4535.00 15.00 44.51 k (%) 0.33 1.49 1.65 1.82 3.42 0.17 1.64 la (mg/kg) 9.00 33.00 38.00 42.30 71.20 4.60 37.12 mg (%) 0.23 0.61 0.75 1.07 7.52 0.18 0.86 mn (mg/kg) 131.00 462.00 579.00 730.00 5619.00 131.00 579.60 na (%) 0.11 0.76 1.03 1.24 3.21 0.24 0.94 nb (mg/kg) 1.00 8.00 9.00 10.40 24.10 1.00 9.13 ni (mg/kg) 9.20 25.90 32.60 45.00 427.00 8.60 34.81 p (%) 0.02 0.05 0.07 0.09 0.41 0.02 0.07 pb (mg/kg) 14.00 22.00 25.75 32.00 699.00 4.75 28.11 sc (mg/kg) 2.00 9.00 10.00 12.00 25.00 2.00 10.09 sn (mg/kg) 0.10 3.30 4.00 5.00 70.00 1.00 3.99 sr (mg/kg) 35.00 100.00 111.00 127.00 1090.00 12.00 115.38 th (mg/kg) 2.00 10.00 11.60 12.90 20.00 1.40 11.15 ti (%) 0.08 0.35 0.40 0.43 1.13 0.04 0.39 v (mg/kg) 22.00 79.00 89.00 105.00 238.00 12.00 91.58 y (mg/kg) 3.00 13.00 16.60 19.60 48.00 3.40 15.56 zn (mg/kg) 28.00 62.00 72.00 93.00 1432.00 14.00 78.92 zr (mg/kg) 9.00 26.00 36.00 42.30 1583.00 7.66 33.20 ph 2.03 5.01 5.72 6.81 8.09 0.86 5.79 note: q1, med, and q3 are the sample quartiles (25th, 50th and 75th percentile); mad is median absolute deviation; g is geometric mean g eo lo gi a c ro at ic a 160 geologia croatica 78/2 on coda arises from the fact that the latter sometimes simply reaffirms what has already been confirmed by traditional methods. in this case, though, attention is required because “... either we have been lucky with our traditional methods, or at least the new methodology must be correct in this case” (aitchison, 2008). 2.4.1.2. discriminant function analysis – creating a strategy dfa is one of the traditional multivariate statistical techniques, which is extremely helpful in creating the predictive model of a two­ or multiple­group discrimination based on a suite of independent (predictor) variables. in its various practical considerations in geosciences, dfa is commonly used when geological rationale requires the application of some autonomous discriminating criterion concerning the variables in the analysed suite of data. it is an efficient tool in handling the large number of quantitative attributes, reducing problems with organization, distinction, or comparison of sizeable databases, to gain a higher degree of understanding of the various underlying geological, geochemical or environmental controls. in addition, the data managed in this way may also result in mapping properties that help to clarify the inherent relationships among the original variables. the aims and principles of dfa are described in many statistical textbooks (e.g. davis, 1973, 1986; dillon & goldstein, 1984; rock, 1988; reimann et al., 2008) and are regularly put forward by the present authors in various geochemical, environmental, sedimentological, bauxite, and other studies (peh et al., 2008; peh & halamić, 2010; kovačević galović et al., 2012; halamić et al., 2012; peh & kovačević galović, 2014, 2016; galović & peh, 2016; grizelj et al., 2017; šorša et al., 2018a; brunović et al., 2019; hasan et al., 2020; gizdavec et al., 2022; ilijanić et al., 2023; galović et al., 2024). as a multivariate method, it was applied in this study to process a vast body of data (1,254 samples) in a manner accommodating the most efficient concordance between the soil geochemical signature and various aspects of the surrounding soil environment in the pannonian part of croatia. characterisation of the grouping criteria is critical in this regard because geochemical patterns in the sampling media (upper soils in this case), typically follow the overall perspective on a regional scale – geological, environmental and other intrinsic controls predominating in the investigated area (croatian pannonian region). these principles are autonomous concerning the analysed (independent) variables (see, e.g., rock, 1988). a discriminant analysis panel from the statistica statistical software package, version 7.1 (statsoft inc., 2006), was used to achieve the best possible separation between the á priori defined groups and to determine the geological/ecological/ pedological factors responsible for the structure of the input data. in this procedure, the applied statistical package (linear discriminant function) automatically finds the best variable patterns, allowing computed discriminant functions to make the maximum contribution to the multi­group discrimination. in this way, casual confusion and possible misinterpretation of group memberships in the computed model is prevented, at least to the extent that dfa is applied for confirmatory purposes. one of the most decisive standards appropriate to the group description in this case is represented by the underlying geology (lithology). it draws heavily on earlier research work (hasan et al., 2020) that built the strong geochemical contrast between the soil geochemistry of the two geological/ structural regions in croatia roughly delineated as din and pan. in particular, that study demonstrated that even the lithologically monotonous terrain, such as the dinaric­coastal region, which is characterized by predominantly carbonate bedrock, appears sufficiently diverse to affect the geochemical signal in the overlying soils. furthermore, it showed that recent investigations concerning the gemas project (geochemical mapping of agricultural and grazing land soil) (reimann et al., 2014) validated the suitability of the land cover classes, borrowed from the clc inventory, in the search for environmental impacts on the geochemical composition of soils. finally, soils by their very nature are a repository of various processes, past or present, participating in soil formation and leaving distinctive geochemical signals at both local and regional levels in the final analysis. to this extent, various soil classifications, such as fao (developed by the food and agriculture organization of the united nations), offer valuable generalizations about pedogenesis with respect to the interaction between the key soil­forming factors. following the guidelines declared above, three substantive issues in this study were delineated with respect to the grouping strategy: geology, clc, and soil. the first two of these include a different number of classes depending on the nature of the grouping variables which stem, at least partly, from the familiar ‘clorpt’ state equation: s = f (dfcl, o, r, p, t); published by jenny (1941), while the last one represents the final solution of the entire process. in other words, the soil is the function of climate, organisms, relief, parent material and time, explaining the role of variables (state factors) in the process of soil formation (e.g., phillips, 1998, 2002; bockheim et al., 2005). later on, this state­factor model (unsolvable in its original form) was extended to include the ecosystem, soil, vegetation and fauna (e.g., bockheim & gennadiyev, 2010) and finally reviewed in the work on soil complexity and pedogenesis (phillips, 2017). in this study, the groups are formed using the following references: 1) the geology model is based on the general geology of the investigated area introduced from the geological map of the republic of croatia, 1:300,000 (hgi­cgs, 2009) (13 groups); 2) the clc model exploited the most general level of standard clc classification (label 1) from the clc project 2018 (4 groups; where the clc2018 groups labelled as 4 and 5 were joined into one), while; 3) the soil model made use of the fao unesco pedological map of the republic of croatia, scale 1,000,000 of pannonian basin (bogunović et al., 1998; 8 groups). all three models comprise 1,254 valid objects altogether (n) and the same suite of variables (p = 28), as described in table 5. 2.4.2. the map generation the geochemical maps were created with the arcgis extension geostatistical analyst. inverse distance weighting (idw) was used to visualise the maps with the discriminant scores. the method parameters were the same as those used to create the geochemical maps of the elements in the geochemical atlas of croatia (šorša, 2009). the calculation is performed https://en.wikipedia.org/wiki/food_and_agriculture_organization_of_the_united_nations https://en.wikipedia.org/wiki/food_and_agriculture_organization_of_the_united_nations g eologia c roatica 161pjanić et al.: geochemical map of croatia – key findings and legacy of geochemical mapping in the pannonian basin with a maximum of 9 neighbouring points and a minimum of 6 points. the calculated area is a circle with a diameter of 10 km, choosing a power value of p = 2 to achieve an optimal and balanced mutual influence between the sample points. the results of the discriminant scores are categorised into 8 percentile classes, with the boundaries of each class at the 5th, 10th, 25th, 50th, 75th, 90th and 98th percentile. the spatial distribution of each class is shown on the map in the form of a polygon. to achieve a smoother transition on the maps, a new polygon was used for every 2nd percentile. the colours range from shades of blue for low concentrations to green­yellow­ orange and red for high concentrations. 2.5. description of the studied groups 2.5.1. lithological groups due to the great lithological diversity, and the relatively small distribution of individual types of rocks, we tried to classify them into groups with common characteristics. the idea was to define each group by its lithological similarities and a similar time of formation. in addition, some groups were formed, based on the genetic characteristics of certain types of rocks. for example, group two includes ophiolitic rocks, but also other types of rocks that are genetically related to them (fig. 2a, b; tables 1, 4). group 1 (geo1) – includes the oldest metamorphic rocks in northern croatia (neoproterozoic), which are found in the mountains of the psunj, krndija, and a small part of moslavačka gora. these are metamorphites from the progressive­ metamorphic series such as ortho­ and paragneisses, amphibolites, amphibole schists, metagabbros, marbles, granite and granitoid deposits, chlorite schists and graphite schists. group 2 (geo2) – consists mainly of ophiolitic rocks (triassic and jurassic) and sedimentary rocks that are genetically related to them and metamorphic products created by the metamorphosis of ophiolitic rocks. the rocks of this group are distributed in a relatively narrow ophiolite belt that extends from the central dinarides of bosnia and herzegovina over the zrinska and samoborska gora mts., then over medvednica and ivanščica to the kalnik mts, where it sinks to the northeast beneath tertiary and quaternary sediments and continues into hungary. ultramafic rocks (lercolites and serpentinised peridotites), as well as mafic rocks (gabbros, diabases and basalts), are included in this group. additionally, the group comprises amphibolites and various varieties of green ortho­schists derived from ophiolitic rocks. associated with this group of rocks are the sedimentary rocks of the ophiolitic mélange (matrix­supported conglomerates, sandstones and siltites) as well as low grade metamorphic rocks including slates, phyllites, metasandstones and quartz schists. group 3 (geo3) – contains metamorphic, low grade metamorphic and sedimentary rocks of the palaeozoic (devonian and carboniferous), including lower permian deposits (mainly products of the variscan orogeny). these rocks form parts of the trgovska gora, petrova gora, samoborska gora, medvednica, papuk, psunj and krndija mts. the rocks are represented by different types of schists, phyllites, metagreywackes, marbleized limestones, marbles, recrystallized dolomites, shales, siltites, sandstones, fine­ grained conglomerates, argillaceous limestones and dolomites. group 4 (geo4) – consists mainly of clastic deposits of the upper permian and lower triassic. part of these sediments are products of terrestrial depositional environments. the rocks extend over the papuk, krndija, petrova gora, žumberak, samoborska gora, medvednica, ivanščica, strahinjščica and ravna gora mts. they comprise shales, siltites, sandstones, conglomerates, marls and biocalcarenites. group 5 (geo5) – the rocks formed on the mesozoic carbonate platform are included in this group. these are predominantly carbonate deposits of middle triassic to the middle jurassic age. they were detected on the trgovska and petrova gora, žumberak, medvednica, ivanščica, strahinjščica, kuna and ravna gora, kalnik, psunj, papuk, požeška gora and krndija mts, and they consist predominantly of limestones and dolomites. in addition, shales, siltites, sandstones, deep­water limestones and tuffs of volcano­ sedimentary origin (pietra verde) are also represented. table 5. grouping criteria. n geology n soil n clc n 1 metamorphic rocks (geo1) 32 chernozem (ch) 31 agricultural surfaces (agrs) 662 2 ophiolites (geo2) 9 cambisols (cm) 182 artificial surfaces (arts) 49 3 clastic and carbonate deposits (geo3) 22 fluvisols (fl) 145 forests and seminatural areas (fsna) 505 4 induanian and olenekian deposits (geo4) 7 gley (gl) 293 wetlands (wetl) 38 5 carbonate sediments (geo5) 16 leptosols (lp) 83 6 carbonate flysch and clastic sediments (geo6) 12 luvisols (lv) 257 7 clastic and carbonate deposits with volcanics (geo7) 32 podzols (pz) 250 8 limestone and clastic deposits with volcanics (geo8) 77 urban soils (urb) 13 9 clastic deposits, sands, clays, coal (geo9) 156 10 loess and marsh deposits (geo10) 489 11 aeolian sands (geo11) 32 12 deluvial-proluvial deposits (geo12) 38 13 alluvial deposits (geo13) 332 total 1254 1254 1254 note: n = number of groups; n = number of cases in each respective group (∑n = 1,254) g eo lo gi a c ro at ic a 162 geologia croatica 78/2 group 6 (geo6) – sediments from the lower cretaceous to the palaeogene are included in this group and are found on the zrinska gora, žumberak, medvednica and požeška gora mts. these deposits consist of turbidites (rhythmic alternation of shales, siltites, sandstones and conglomerates), then greywacke sandstones, calcarenites, calcrudites, conglomerates and cherts. in addition, hemipelagic limestones of the scaglia facies and shallow marine biogenic limestones also appear. group 7 (geo7) – includes clastic sediments and volcanics of oligocene and lower miocene ages, which are distributed on the kalnik, ivanščica, strahinjščica and kuna gora mts. in addition, clastics with carbonate rocks from the upper part of the lower miocene were also included in this group. they are found around almost all the mountains in northwestern croatia. these rocks are made up of sands, sandstones, gravels, conglomerates, marls, clays, siltites, coals and tuffs as well as congeria limestones. group 8 (geo8) – limestones, clastic deposits with volcanics and carbonate­clastic deposits of the middle and lower part of the upper miocene belong to this group. they consist of lithothamnium limestones, argillaceous limestones, micritic and granular limestones, sandstones, conglomerates and marls, rhyolites and acid tuffs. all these rocks surround most of the northern croatian mountains, and on dilj mt. they form its core as well. furthermore, they were mapped on the zrinska gora and bansko brdo mts. in baranja. group 9 (geo9) – comprises sedimentary rocks from the upper miocene to the plio­quaternary. these are clastic sediments such as marls, siltstones, multi­coloured sands and sandstones, calcite clays, calcarenites, gravels, coal and carbonaceous clays. these deposits are found around all the mountains of northern croatia, and they fill the drava and sava basins and the karlovac and bjelovar depressions. group 10 (geo10) – this group consists of deposits of terrestrial and marsh loess, which originate from the alps. they are found on bilogora mt., in moslavina, in the bjelovar and ilova depressions, in the karlovac and požega valleys, on the đakovo–vinkovci–vukovar plateau, and on the erdut and bansko brdo hills. terrestrial loess consists of silts and fine­ grained sands, while marsh loess consists of clayey silts and sands, and sands. marsh loess was formed by the deposition of aeolian sediment directly into the lake or marsh environment. group 11 (geo11) – consists only of aeolian sands, which were formed by the blowing of fine­grained river (terrace) sediments of the mura and drava rivers by the north­ west winds, which explains why these deposits are found only along the southern edges of the drava and mura basins. these sediments are spread in the northern part of međimurje province from mursko središće in the northwest to the goričan towns in the southeast. south of the drava river, these deposits are found in a relatively narrow belt from the towns of varaždin to ludbreg, continuing south­east along the northern slopes of bilogora mt. to the virovitica town, from where they extend eastwards directly along the drava river to valpovo. in that area, hectometre­ to kilometre­long dunes with an approximate northwest­southeast orientation are also visible. aeolian sediment consists of sands and siltstones. group 12 (geo12) – includes deluvial­proluvial deposits found in larger areas at the foothills of the bilogora, krndija, moslavačka gora and psunj mts., erdutsko brdo hill and in the area between the towns of sunja and dubica in the banovina province. the composition of these sediments depends directly on the eroded substrate, and they are mostly composed of blocks, rock fragments, semi­rounded gravels, sands and silts. group 13 (geo13) – consists of the youngest holocene sediments, which are still formed today in valleys (floodplains) and riverbeds, and streams in the entire area of northern croatia. these sediments occupy the largest areas in the valleys of the sava, drava, mura, krapina, kupa, lonja, česma, ilova, pakra, orljava, karašica and danube rivers. the sediments consist of unconsolidated gravels, sands, silts and clays. 2.5.2. soil groups bogunović et al. (1998) harmonised the croatian pedological nomenclature with the fao nomenclature and published the fao unesco pedological map of the republic of croatia (fig. 2c; table 2). since the pedological data in the european soil database (panagos, 2006) are more general than those of bogunović et al. (1998), the grouping criterion of the latter was used. the criterion for a particular group was the soil type of the dominant units, except for three soil types that were present in an insignificant number of our sampling sites. these soil types were linked by other units (1), regosol was linked to glaysols, (2) calcic chernozem was linked to cambisol, and (3) gleyic and calcic chernozem were linked to gleysols (fig. 2c, d; tables 2, 4). the unmapped urban areas, such as the city of zagreb, were identified by the authors as areas with urban soils. group fl – fluvisols from cartographic unit 1 are soils formed by the deposition of soil particles on the floodplains of rivers. the relatively young quaternary age of the sediments and the repeated flooding and deposition of new particles have prevented pedogenic processes, so fluvisols are classified as underdeveloped hydromorphic soils. these soils are developed in the alluvial and lacustrine deposits of the sava, drava, mura and danube rivers in the pannonian basin. group gl – the gleysols identified in units 2, 3, 4 and 31 and the regosols from unit 6 are water­saturated most of the year. gleysols are mainly found along the rivers such as the sava, drava, mura, lonja, kupa, krapina, česma, ilova, pakra, orljava and danube, predominantly in lowland areas. their water­saturated condition facilitates the formation of gleys, which are characterised by a grey­blue colour caused by the reduction of iron under water­saturated conditions. regosols, which have been added to this fl group, are shallow, poorly developed soils on loose sediments such as loess, sand, marl and flysch. they are found on loess in eastern slavonia (baranja, fruška gora mt.). group lp – leptosols from units 8, 9 and 11 are shallow soils with limited pedogenic development, typically overlying hard rock. these soils show minimal horizon development due to the limited material available for soil formation and are often found in mountainous or rocky terrain. in the pannonian g eologia c roatica 163pjanić et al.: geochemical map of croatia – key findings and legacy of geochemical mapping in the pannonian basin basin, they develop on the slopes of “inselgebirge” in slavonija (dilj, krdnija, moslavačka gora mts.) and banovina (zrinska gora mt.), then in the hilly hrvatsko zagorje and međimurje provinces. group cm – cambisols occur in units 14, 15, 16, 18 and 19, and are moderately developed, young soils. these soils are characteristic of regions where weathering and biological activity are strong but have not yet reached advanced stages of soil maturity. eutric cambisols are mainly found on the loess plateaus of the đakovo, vinkovci, vukovar and at the “inselgebirge” (bansko brdo and erdutsko brdo hills, and the dilj, papuk, bilogora, moslavačka gora, žumberak mts). group ch – chernozems dominate in cartographic units 20 and 21. they are rich in organic matter and secondary calcium carbonate concretions. these fertile, deep black soils, which occur mainly in eastern croatia, are known in areas such as dalj and zmajevac (galović et al., 2023; poch et al., 2024). group lv – luvisols are found in cartographic units 22 and 23. they are the most common soil type in croatia, particularly widespread in the pannonian basin. a luvisol is an automorphic soil type with a subsurface horizon with high clay accumulation and high base saturation. luvisols are particularly common in međimurje, hrvatsko zagorje and in the hilly areas of vukomeričke gorice and petrova gora. these soils also extend across the ivanščica, kalnik, bilogora, moslavačka gora, papuk and krndija mts. and are occasionally found in srijem and central baranja. group pz – podzols (all sampling sites are located in podzoluvisols), assigned to cartographic unit 25, are acidic and waterlogged soils in which organic matter accumulates faster than it decomposes, leading to the leaching of minerals and the development of a spodic horizon. these soils occur almost the entire studied area, except in međimurje and hrvatsko zagorje provinces, where podzoluvisols occur only sporadically. group urb – urban soils; includes soils in urban areas that are not mapped and are labelled as “cities” on the fao unesco pedological maps (bogunović et al., 1998). urban soils have developed under anthropogenic influences and could vary considerably in their properties due to disturbances such as construction, landscaping and pollution, which affect their natural soil profile and function. the absence of the cartographic soil units 5, 7, 10, 12, 13, 17, 24, 26, 27, 28, 29, and 32 in the pan region illustrates the regional specificities in soil formation and distribution, underlining the importance of local geological, hydrological and climatic conditions in pedogenesis. 2.5.3. land use and land cover groups for the clc classification, the most general level 1 of the standard clc classification from the corine land cover (2018) raster data of the european environment agency was used and summarised in 4 groups. the first three groups correspond to the first three clc classes: (1) artificial surfaces/urban or built­up areas (arts), (2) agricultural land (agrs) and (3) forests/forest land semi­natural area (fsna). the fourth group was formed by combining the two clc level 1 classes wetlands and waterbodies into one group (4) wetlands (wetl) (fig. 2e, f; tables 3, 4). group arts – includes areas with strong anthropogenic influences. the sampling sites were located in the three clc2018 areas: discontinuous urban fabric (buildings, with associated land, access roads, and car parks), industrial or commercial units (manufacturing, trade, services, and transport, with associated land) and sports and leisure facilities (parks, sports facilities) (fig. 2e, f; tables 3, 4). group agrs – includes areas with various types of agricultural production: non­irrigated arable land, permanently irrigated land, vineyards, fruit trees and berry plantations, pastures, complex cultivation patterns and land, mainly agricultural land with significant areas of natural vegetation. group fsna – represents ground covered with forest and semi­natural areas. this group includes broad­leaved forests, coniferous forests, mixed forests, natural grasslands and transitional woodland shrubs. group wetl – integrate inland marshes flooded for most of the year, natural and artificial watercourses that serve as drainage channels, and water bodies such as lakes, ponds, reservoirs and canals. 3. results and discussion results of the dfa are presented in the common table (table 6) comprising all three exploratory models (tests of residual roots). before that, the overall significance of their discrimination potential is verified by the appropriate multivariate tests (table 7) exposing the vanishingly small associated probabilities (p < 0.000 for overall significance of discrimination), a condition required to securely proceed with calculating discriminant functions (dfs). according to various numbers of groups (k) in each model, the total number of dfs is k­1. notwithstanding the statistical significance of the variation between the observed groups (p­level in table 6), which defines the dimensionality of the discriminant space, only a smaller number of dfs is handled to explain the natural variation between groups. natural variation (geological meaning) hidden behind the original data served as a helpful criterion decreasing the number of discriminant axes to only two or three. however, unlike the karst region, where the lithological contrast between carbonate and siliciclastic facies was clear enough to reduce the number of groups to only a few, the pannonian basin appears as a true mosaic of lithological diversity. as a result, the first three dfs scarcely exceed half of the total variance comprised in the thirteen observed geology groups. 3.1. functional models – labelling the discriminant functions the technique of labelling dfs is explained elsewhere, including the reasons for using scatterplots instead of biplots in the coda analysis (e.g., peh & kovačević galović, 2014; galović & peh, 2016; šorša et al., 2018a). in essence, the structural (mathematical) model is converted into a functional (process) one, which is geochemical at its core. in g eo lo gi a c ro at ic a 164 geologia croatica 78/2 the process, the group centroids (means) are utilised as the proxy for the cloud of single objects in the scatterplot construction to simplify the explanation of the models. scatterplots of group centroids and variable loadings are built for all three discriminant models using the first two dfs explaining the greatest proportion of the between­group variance. models are contrasted using the scatter diagrams of the df1 and df2 pairs of discriminant functions (orthogonal axes) (fig. 3). 3.1.1. geology model in the geology model, generally concerned with the parent­ material state variable (“p”), from the aforementioned “clorpt” state equation, the first discriminant function df1 explaining one­third of the total variance (33.31%) highlights the youngest (quaternary) sediments (table 1; geo10 – geo13) in contrast to all the remaining lithologies, a clearly bipolar relationship (fig. 2a, b; fig. 3a, b; fig. 4a, b; table 6). undoubtedly, soils developed on alluvium and other quaternary deposits stand out as a repository of elements such as y, p, as well as ca and mg, which, together with the ph index, suggest an alkaline environment enriched in residues from artificial fertilizers frequently used on arable pan surfaces. at the other end of the scale, soils formed on clastic rocks (geo3 in particular) are acidic, revealing a similar mechanism of soil acidification as in the mountainous areas of the din region investigated earlier (hasan et al., 2020). this process, occurring simultaneously with illuviation, may dominate soil formation over the siliciclastic bedrock, particularly in pan mountainous areas. in contradistinction to df1, the second discriminant function (df2), explaining a further 17.97% of the total variability of the pannonian geo model (over 50% taken together), indicates a direct relationship between the soils formed on quaternary deposits and those developed on siliciclastic parent rocks outcropping on the pan mountains. grouping of alluvial sediments (geo13) on the lower part of the diagram, together with metamorphic rocks (geo1) and mainly basic rocks (geo2), demonstrates that weathering table 6. tests of residual roots (discriminant functions) for all three models. df eigen value eigen (%) eigen cum canon. r wilks’ l c2 df p-level geology 1 0.849 33.31 33.31 0.678 0.119 2623.7 336 0.000 2 0.458 17.97 51.28 0.560 0.220 1865.9 297 0.000 3 0.330 12.95 64.23 0.498 0.321 1401.2 260 0.000 4 0.233 9.14 73.37 0.434 0.427 1049.9 225 0.000 5 0.176 6.90 80.27 0.387 0.526 792.1 192 0.000 6 0.149 5.84 86.11 0.360 0.619 592.1 161 0.000 7 0.117 4.59 90.70 0.324 0.711 420.9 132 0.000 8 0.094 3.69 94.39 0.293 0.794 284.2 105 0.000 9 0.057 2.24 96.63 0.232 0.869 173.2 80 0.000 10 0.045 1.76 98.39 0.209 0.918 104.9 57 0.000 11 0.025 0.98 99.37 0.155 0.960 50.1 36 0.060 12 0.016 0.63 100.00 0.127 0.984 20.0 17 0.272 soil 1 1.041 51.59 51.59 0.714 0.205 1958.0 196 0.000 2 0.408 20.22 71.81 0.538 0.418 1076.6 162 0.000 3 0.206 10.21 82.02 0.413 0.589 654.1 130 0.000 4 0.171 8.47 90.49 0.382 0.710 423.3 100 0.000 5 0.097 4.81 95.30 0.297 0.831 228.5 72 0.000 6 0.067 3.32 98.62 0.251 0.912 114.4 46 0.000 7 0.028 1.38 100.00 0.165 0.973 34.0 22 0.049 clc 1 0.322 59.85 59.85 0.494 0.617 597.0 84 0.000 2 0.163 30.30 98.15 0.375 0.816 251.4 54 0.000 3 0.053 9.85 100.00 0.225 0.950 64.1 26 0.000 table 7. multivariate test for overall significance of discrimination. models geology soil clc no. of groups 13 8 4 wilks’ lambda 0.119 0.205 0.617 approximate f ratio 8.505 11.118 7.628 degrees of freedom [336; 13463] [196; 8314] [84; 3659] p level p < 0.000 p < 0.000 p < 0.000 g eologia c roatica 165pjanić et al.: geochemical map of croatia – key findings and legacy of geochemical mapping in the pannonian basin figure 3. comparison between variables and groups (centroids) in the discriminant function models geology, soil and clc of the clr-transformed data. in the geology model: scatterplots of a) variable loadings and b) groups in the reduced discriminant space of the first two discriminant functions (df1–df2); in the soil model: scatterplots of c) variable loadings and d) df1–df2; in the clc model: scatterplots of e) variable loadings and f) df1–df2. g eo lo gi a c ro at ic a 166 geologia croatica 78/2 products of the latter are transported to the numerous streams feeding the alluvial plains. concerning the rest of the quaternary deposits (geo10–geo11–geo12), as opposed to geo13 on df2, the pertinent soils have accumulated a host of elements of low mobility such as ti, nb, la and th, most probably as a result of the high stability of their hosting minerals (both oxides and silicates), such as monazite and xenotime. also, the occurrence of zr on df2, compatible with the soils developed on the latter group of quaternary deposits, indicates the presence of detrital heavy minerals such as zircon, suggesting either their origin from related df2 lithological facies, (geo9–geo8–geo4 in particular), or from external material of aeolian origin. soils developed on geo13/geo1– geo2 lithologies appear enriched mostly in phe (potentially harmful elements) (zn, pb, hg), possibly of anthropogenic origin. however, the absence of elements constituting the clay minerals (k, na and al, together with ti, ba and others) calls for attention, and a solution must be sought in residual variance that may explain such unusual behaviour. in effect, df3 as a true monopolar function (explaining further 12.95% of the total variability) clarifies the unique position of the metamorphic rocks (geo1) in the overall scheme betraying the latter as a main source of clay­forming elements in the pertinent soils and their acidulous character (low ph; fig. 3a, b). 3.1.2. soil model soil as the final product of the “state function” inherently includes all the so­called state factors that more or less participated in its formation. thus, the picture displayed by the soil­model dfa scatterplots is the natural canvas painted on the earth's surface in its most recent geological history. these plots (fig. 3c, d) represent a collection of soil groups with their associated geochemical imprints originating from various soil­forming processes characteristic of the croatian pan region. df1 explains almost 52% of the total variability of the soil system emphasizing the ubiquity of fluvisols (fl), the soil group characteristic for the investigated region, since its formation is related to environments that are, by definition, periodically flooded areas of alluvial plains, river fans and valleys (fig. 2c, d; fig. 4c, d; tables 2, 6). naturally, its formation is fixed on recent (mainly holocene) f luvial, lacustrine or alluvial deposits, the source material of which originates from rocks comprising the inner pannonian mountains (as defined in the geology model). in this regard, one cannot neglect the alkaline character of pan fluvisols with high ph and enrichment in elements such as ca and mg. however, at the same time, it is obvious that these soils are depots of various phes, including amongst others, pb, zn, hg, cu, ni, which enter the system through various human activities, mostly industry (romić & romić, 2003; šorša et al., 2018a, b). in addition, the presence of p, although to a lesser degree, indicates agricultural activity on fluvisols, affecting their capacity to sustain plant or animal productivity in the long term. relatively close to fl stands the group of urban soils (urb) where the problem with phes is further highlighted. at the other end of the spectrum, podzols (pz) and luvisols (lv) are enriched in clayey components and characterised by their excessive acidity. contrary to df1, the second discriminant function (df2), explaining 20.22% of the total variability is more obviously bipolar contrasting leptosols (lp) and, partly, cambisols (cm) with gleys (gl) and chernozem (ch), based on the enrichment/depletion relationship of p and y (present in phosphogypsum fertilizers) on the one side, and mn on the other. this picture separates agricultural from other soils, since yttrium is widely applied in modern industry and farming, while phosphorus is one of the essential nutrients, occurring in agricultural areas used for permanent crops (phosphogypsum fertilizers). however, phosphorus is one of the main factors of eutrophication, especially in low­lying areas with poor drainage, where dissolved nutrients may stimulate the growth of aquatic species, resulting in anoxia. this process is particularly relevant to gleys (gl) saturated with (oxygen­depleted) groundwater. in contrast, leptosols (lp) are generally well­drained soils, not suitable for agricultural utilisation but with characteristics favourable for forestry. in this regard, the role of mn as a critical micronutrient for plants may be accumulated in surface soils (leptosols in this case) after a few decades as a consequence of cycling through vegetation, that is, uptake and litterfall. as for the third discriminant function (df3, 10.21%), it is also concerned with leptosols but in this case focuses on the distribution of heavy metals (cu, ni, co) that are most probably related to the underlying ophiolitic bedrock building the central pan area. 3.1.3. clc model the most typical level (label 1) of the clc model, generally relating to the vegetation and animal properties and ecosystem as a whole in jenny’s extended soil functional­factorial model. jenny (1941), as described in bockheim & genna­ diyev (2010), explains over 90% of the total variability by the first two (df1 and df2) of the three discriminant functions altogether (fig. 3e, f; fig. 4e, f; table 6). the first discriminant function is essential (59.85%). it highlights the strong contrast between soils developed on agricultural and artificial surfaces (agrs/arts) with those formed in forests and semi­natural areas and wetlands, when taken together (fsna/wetl). this distinction is based essentially on the strong presence of the same elements as in the geo model, referring to groups of quaternary lithology (geo10–geo13), namely p, y (ca) and high ph coefficient revealing the alkaline conditions. a similar impact of the inescapable anthropogenic impact of fertilizers is expected between these geo and clc groups. however, in the latter case, cu also added to agrs an arts group (fig. 3e, f), indicating that a portion of arable land may be covered with vineyards (cupric sulphate) (romić et al., 2004). the second clc discriminant function (df2) (additional 30.30% of total variance) is strongly monopolar, separating wetland surfaces from all other groups. the wetl group is generally alkaline, characterised by the presence of ca and mg, including a high ph index (most probably from sewage systems). however, the occurrence of phe such as zn, hg and pb indicates that lowlands are highly susceptible to heavy metal accumulation additionally affecting the ecosystem by increasing toxicity, especially along the regional rivers such g eologia c roatica 167pjanić et al.: geochemical map of croatia – key findings and legacy of geochemical mapping in the pannonian basin figure 4. discriminant score maps representing areal distribution of the first and second discriminant function of the models: geology – a) df1, b) df2; soil – c) df1, d) df2; and clc – e) df1, f) df2. the increasing influence of the respective geochemical signatures is displayed in warm colours (yellow-orange-red). g eo lo gi a c ro at ic a 168 geologia croatica 78/2 as the drava and sava (pavlović et al., 2004; pavlović et al., 2019; oreščanin et al., 2004; šajn et al., 2011; halamić et al., 2012). 3.1.4. classification issues classification efficacy serves as a robust indicator by which the integrity of the previously (a priori) delineated groups can be checked, weighing mathematically “predicted” (computed) against original (observed) classifications (table 5). this reasoned evaluation of group membership of each sample reveals that a considerable proportion of the original affiliations proved incorrect, which is, without doubt, a result of the complex interaction between state factors involved in soil formation. in contradistinction to the din region (hasan et al., 2020), where the preponderance of the carbonate bedrock strongly influenced the active soil forming processes toward the characteristic patterns in each investigated model, resulting in over 70% correct assignments in each division, the pan region is obviously more complex. unquestionably, the increased variation in bedrock lithologies can be considered the main cause of this image as the diverse siliciclastic bedrock, composed of a variety of sedimentary, igneous and metamorphic rocks, is not easy to separate based solely on geochemistry. it is particularly typical for the youngest, quaternary sediments, where, for example, the majority of soil samples collected over the units mapped as deluvial­proluvial deposits (geo12) changed their group membership to loess and marsh deposits (geo10), resulting in a mere 5.26% correct affiliation (table 8). incidentally, it is a typical gravity­centring pattern of group assignment where unstable groups tend to centre their “lost” members on some group with the highest number of samples. the analogue in the dinaric (din) region is, quite naturally, the carbonate lithology which is why most of the samples that were collected on carbonate bedrock were labelled á priori as “carbonate clastic rocks” assembled post hoc around the more general lithological group defined as “carbonate rocks in general” (hasan et al., 2020). in the soil model, the samples classified as urban soils (urb), with merely 7.69% of correct memberships, changed table 8. classification matrix. observed groups predicted groups geology g1 g2 g3 g4 g5 g6 g7 g8 g9 g10 g11 g12 g13 total correct % g1 21 0 2 0 1 1 0 0 3 3 0 0 1 32 65.63 g2 0 4 0 0 0 2 1 0 2 0 0 0 0 9 44.44 g3 1 0 16 0 0 1 2 2 0 0 0 0 0 22 72.73 g4 0 0 2 2 1 0 0 0 0 2 0 0 0 7 28.57 g5 1 0 1 0 7 0 1 0 1 3 0 0 2 16 43.75 g6 2 0 0 0 0 6 0 0 2 0 0 0 2 12 50.00 g7 1 0 1 0 0 2 12 5 3 5 0 1 2 32 37.50 g8 1 0 2 1 0 2 1 30 18 18 1 0 3 77 38.96 g9 3 0 7 0 1 1 1 7 73 46 2 3 12 156 46.79 g10 5 0 0 0 0 1 2 4 31 394 6 2 44 489 80.57 g11 0 0 0 0 0 0 0 0 0 14 13 1 4 32 40.63 g12 1 0 1 0 0 0 0 2 5 25 0 2 2 38 5.26 g13 0 2 3 0 3 1 1 7 6 101 10 1 197 332 59.34 total 36 6 35 3 13 17 21 57 144 611 32 10 269 1254 61.96 soil fl cm pz gl lv lp urb ch total correct % fl 104 1 0 33 2 3 1 1 145 71.72 cm 12 74 21 18 34 8 2 13 182 40.66 pz 0 20 104 54 66 4 2 0 250 41.60 gl 18 7 39 178 34 6 2 9 293 60.75 lv 3 23 49 32 138 7 0 5 257 53.70 lp 2 19 4 5 20 33 0 0 83 39.76 urb 3 1 1 3 3 1 1 0 13 7.69 ch 1 0 0 2 3 0 0 25 31 80.65 total 143 145 218 325 300 62 8 53 1254 52.39 clc fsna agrs arts wetl total correct % fsna 284 186 6 29 505 56.24 agrs 107 536 7 12 662 80.97 arts 2 39 7 1 49 14.29 wetl 1 19 0 18 38 47.37 total 394 780 20 60 1254 67.38 g eologia c roatica 169pjanić et al.: geochemical map of croatia – key findings and legacy of geochemical mapping in the pannonian basin their affiliation by being deployed to various other soil types, mostly gleysols (gl), luvisols (lv) and fluvisols (fl) indicating, perhaps, inappropriate labelling for this type of soil which denotes more environmental (human­induced, in particular) than soil­based characteristics. this implies that the unmapped soils in the urban area are not predominantly under anthropogenic influence, but retain their pedological properties. as the number of sampling sites in the urb group is small (13 sites), this conclusion is rather tentative. in bypassing the natural soil­forming processes in this way, this label becomes devoid of true meaning in the soil classification system (table 8). in the clc model with only four á priori defined groups, the misclassification is emphasised further, especially with regards to the group of artificial surfaces (arts), the classification rate of which amounts to a mediocre 14.29%. similarly, as in the case of “urban soils” (urb) in the soil model that lose their members to more “natural” groups, here the arts division distributes its members to the group of agricultural surfaces (agrs) (tables 5, 8) indicating instability of the so­called “human­impacted” classes whenever they are used for classification purposes. as for the wetland surfaces (wetl), half of its members change their affiliation to agricultural surfaces (agrs) emphasizing the ubiquitous importance of this latter type of environment in the pannonian region, specifically in the areas covered by overbank and floodplain sediments. 4. conclusions the application of dfa to geological, soil, land use and land cover data from the pannonian basin provides significant insights into the geochemical and environmental processes in the topsoil layer. the results highlight lithological and pedological diversity, and consequently land use and land cover, with the first two discriminant functions df1 and df2 explaining a significant proportion of the total variance. 1. in this study, discriminant function models were built based on compositional data analysis for the geochemical survey of topsoils in the pannonian basin of croatia and cross­comparison of their geochemical signatures among the selected groups of geological, pedological and land use/land cover divisions. this approach, combining dfa­derived geochemical models with comprehensive environmental data, provides clear insights into the relationships between topsoil processes and geochemical variations according to geology, pedology, land use and land cover. 2. the geology model with the first discriminant function – df1 explains one third of the variance (33.31%) and shows the clear bipolar relationship between quaternary sediments and older rocks. this function distinguishes topsoils on quaternary deposits, which are enriched in elements indicative of an alkaline environment from soils formed on older, more acidic rocks such as ophiolites and clastic rocks containing some carbonates. the second discriminant function – df2 clarifies 17.97% of the total variability. df2 also discriminates between soils on alluvial sediments and those on metamorphic and ophiolitic rocks, indicating a significant transport of weathering products in alluvial plains. df3 explains 12.95% of the variability and emphasises the unique geochemical signature of soils on metamorphic rocks and their role in the formation of clay minerals and soil acidification. 3. the soil model reflects the multi­layered nature of soil formation processes, with df1 accounting for the largest proportion of variability (51.59%). this feature emphasises the prevalence of fluvisols in the region, associated with recent fluvial and alluvial deposits, as well as their enrichment with essential nutrients and potentially harmful elements due to human activities. df2 explains 20.22% of the total variability and is almost bipolar. it compares agricultural soils enriched with phosphorus and yttrium from fertilisers with other soil types and shows the impact of agricultural practices on soil chemistry. df3 describes only 10.21% of the variability and focuses on the distribution of heavy metals in leptosols, especially those overlying ophiolitic bedrock, and explains the influence of underlying geology on soil composition. 4. the clc model with df1 (59.85%) and df2 (30.30%) together explaining over 90% of the total variability, describes the strong contrast between soils on agricultural/artificial land and those in forests, semi­ natural areas and wetlands. df1 highlights the anthropogenic inf luences on agricultural soils characterised by the presence of phosphorus, yttrium and high ph, while df2 emphasizes wetlands characterised by alkaline conditions and the accumulation of heavy metals, ref lecting their susceptibility to pollution and the accumulation of heavy metals from regional rivers. 5. the effectiveness of the classification shows that the complex factors of soil formation led to considerable misclassification. the diversity of lithological units, especially in quaternary sediments, makes it difficult to delineate geochemical groups, for example, deluvial­ proluvial deposits (geo12) only had an affiliation rate of 5.26%. urban soils, with only 7.69% being a correct classification, are often misclassified as other soil types, suggesting that their current classification does not accurately reflect their pedological properties. in addition, artificial surfaces had a high misclassification rate of 14.29%. they were frequently assigned to agricultural land, indicating anthropogenic influence. the results of this study illustrate the geochemical diversity and the complex interactions between geology, soil formation processes, land use and land cover in the pannonian basin. the geochemical signatures of geology, lithology and land use provide an authentic framework for environmental management and further research. acknowledgement this study was financially supported by the ministry of science, education and sports, republic of croatia – scientific project: the basic geochemical map of croatia, number 181­ g eo lo gi a c ro at ic a 170 geologia croatica 78/2 1811096­1181. we are grateful to the associate editor academic goran durn and the anonymous reviewers for their thorough evaluations which significantly improved the manuscript. references acme analytical laboratories ltd. (2007): assaying and geochemical analy­ ses.– acme analytical laboratories ltd., vancouver, 19 p. aitchison, j. (1986): the statistical analysis of compositional data.– cha­ pman and hall, london, new york, 416 p. http://doi.org/10.1007/978­94­ 009­4109­0 aitchison, j. (2008): the single principle of compositional data analysis, continuing fallacies, confusions and misunderstandings and some sugge­ sted remedies.– in: daunis­i­estadella, j. & martín­fernán­ dez, j. (eds.): proceedings of codawork’08, the 3rd compositional da­ ta analysis workshop. university of girona, girona, 1–27. aitchison, j. & egozcue, j.j. (2005): compositional data analysis: whe­ re are we and where should we be heading?– mathematical geology, 37/7, 829–850. http://doi.org/10.1007/s11004­005­7383­7 barceló­vidal, c., martin­fernandez, j.a. & pawlowsky­ glahn, v. (1999): comment on „singularity and nonnormality in the classification of compositional data“ by g.c. bohling, j.c. davis, r.a. olea & j. harff.– mathematical geology, 31, 581–585. bašić, f. (2013): the soils of croatia.– springer dordrecht, 179 p. https://doi. org/10.1007/978­94­007­5815­5 bašić, f., bogunović, m., božić, m., husnjak, s., jurić, i., kisić, i., mesić, m., mirošević, n., romić, d. & žugec, i. (2007): re­ gionalisation of croatian agriculture.– agriculturae conspectus scien­ tificus, 72/1, 27–38. bockheim, j.g. & gennadiyev, a.n. (2010): soil­factorial models and earth system science: a review.– geoderma, 159/3–4, 243–251. https://doi. org/10.1016/j.geoderma.2010.09.005 bockheim, j.g., gennadiyev, a.n., hammer, r.d. & tandarich, j.p. (2005): historical development of key concept in pedology.– geoder­ ma, 124, 23–36. https://doi.org/10.1016/j.geoderma.2004.03.004 bogunović, m., vidaček, ž., racz, z., husnjak, s., špoljar, a. & sraka, m. (1998): fao unesco pedological map of the republic of croatia 1:1.000.000.– university of zagreb, faculty of agriculture, zagreb. brunović, d., miko, s., ilijanić, n., peh, z., hasan, o., kolar, t., šparica miko, m. & razum, i. (2019): holocene foraminiferal and geochemical records in the coastal karst dolines of cres island, croatia.– geologia croatica, 72/1, 19–42. https://doi:10.4154/gc.2019.02 buccianti, a. (2013): is compositional data analysis a way to see beyond the illusion?– computers & geosciences, 50, 165–173. http://doi.org/10. 1016/j.cageo.2012.06.012 buccianti, a. & grunsky, e. (2014): compositional data analysis in geo­ chemistry: are we sure to see what really occurs during natural proces­ ses?– journal of geochemical exploration, 141, 1–5. https://doi.org/10. 1016/j.gexplo.2014.03.022 daunis­i­estadella, j., thió­henestrosa, s. & mateu­figue­ ras, g. (2011): two more things about compositional biplots: quality of projection and inclusion of supplementary elements.– in: egozcue, j.j., tolosana­delgado, r. & ortego, m.i. (eds.): proceedings of the 4th international workshop on compositional data analysis (co­ dawork'11). university of girona, girona, 1–14. davis, j.c. (1973): statistics and data analysis in geology.– john wiley & sons, new york. 550 p. davis, j.c. (1986): statistics and data analysis in geology, 2nd edition.– jo­ hn wiley & sons, new york, 656 p. dillon, w.r. & goldstein, m. (1984): multivariate analysis: methods and applications.– john wiley & sons, new york, 608 p. egozcue, j.j. & pawlowsky­glahn, v. (2006): simplicial geometry for compositional data.– in: buccianti a., mateu­figueras, g. & pawlowsky­glahn, v. (eds.): compositional data analysis in the geosciences: from theory to practice. geological society london, special publication, 264, 145–158. http://doi.org/10.1144/gsl.sp.2006. 264. 01.11 filipčić, a. (2023): klima hrvatske.– in: magaš, d (ed.): velika geografi­ ja hrvatske, knjiga 2. – fizička geografija hrvatske – prirodno­geograf­ ska osnova razvoja [major geography of croatia, book 2 – psyhical geography of croatia – in croatian], university of zadar, department of geography, školska knjiga, zagreb, zadar, 432–467 p. galović, l. & peh, z. (2016): mineralogical discrimination of the pleisto­ cene loess/paleosol sections in srijem and baranja, croatia.– aeolian re­ search, 21, 151–162. http://doi.org/10.1016/j.aeolia.2016.04.006 galović, l., husnjak, s., šorša, a. & martinčević lazar, j. (2023): evidence and mineralogical and physico­chemical properties of chernozem and chernozem­like soils in croatia.– geologia croatica, 76/3, 113–129. https://doi.org/10.4154/gc.2023.08 galović, l., šorša, a. & peh, z. (2024): modelling the paleopedological development of loess/palaeosol sections using discriminant function analysis of compositional geoscience data, case study in eastern croatia.– journal of geochemical exploration, 262, 107473. https://doi.org/10.1016/j. gexplo.2024.107473 gizdavec, n., gašparović, m., miko, s., lužar­oberiter, b., ili­ janić, n. & peh, z. (2022): discrimination of rock units in karst terrains using sentinel­2a imagery.– remote sensing, 14/20, 5169. http://doi:10.3390/rs14205169 grizelj, a., peh, z., tibljaš, d., kovačić, m. & kurečić, t. (2017): mineralogical and geochemical characteristics of miocene pelitic sedi­ mentary rocks from the south­western part of the pannonian basin system (croatia): implications for provenance studies.– geoscience frontiers, 8/1, 65–80. https://doi.org/10.1016/j.gsf.2015.11.009 halamić, j. & miko, s. (eds.) (2009): geochemical atlas of the republic of croatia.– croatian geological survey, zagreb, 87 p. halamić, j., miko, s., peh, z. & galović, l. (2000): upute za izradu "osnovne geokemijske karte republike hrvatske" [guidelines for geochemical mapping of croatia – in croatian]. fond struč. dok., croatian geological survey, 51/2000, 22 p. halamić, j., peh, z., miko, s., galović, l. & šorša, a. (2012): geo­ chemical atlas of croatia: environmental implications and geodynamical thread.– journal of geochemical exploration, 115, 36–46. https://doi.or­ g/10.1016/j.gexpl o.2012.02.006 hasan, o., miko, s., ilijanić, n., brunović, d., dedić, ž., šparica miko, m. & peh, z. (2020): discrimination of topsoil environments in a karst landscape: an outcome of a geochemical mapping campaign.– geochemical transactions, 21, 1. https://doi.org/10.1186/s12932­019­ 0065­z hgi­cgs (hrvatski geološki institut­croatian geological survey) (1992): geološke karte sjeverozapadne hrvatske, m 1:100 000, vrh temeljnog gorja [geological maps of northwestern croatia, scale 1:100,000, the top of the mesozoic basement].– archives of hgi­cgs, 104/92, zagreb. hgi­cgs (hrvatski geološki institut­croatian geological survey) (2009): geološka karta republike hrvatske m 1:300 000 [geological map of republic of croatia, m 1:300,000].– hgi­cgs, depar­ tment for geology, zagreb. https://www.hgi­cgs.hr/geoloske­karte/. ilijanić, n., kovačević galović, e., gizdavec, n., ivkić filipo­ vić, i., miko, s. & peh, z. (2023): geochemical records in subaerial exposure environments in croatia using discriminant function analysis of bauxite data.– frontiers in earth science, 10, 1055435. https://doi. org/10.3389/feart.2022.1055435 iso (2002a): iso 10381­1: soil quality–sampling–part 1: guidance on the de­ sign of sampling programs.– international organization for standardiza­ tion. iso (2002b): iso 10381­2: soil quality–sampling–part 2: guidance on the de­ sign of sampling programs.– international organization for standardiza­ tion. jamičić, d. & crnko, j. (2009): kompleks metamorfnih stijena psunja, krndije i moslavačke gore, prekambrij, pk [complex of metamorphic rocks of the psunj, krndija and moslavačka gora mts., precambrian, http://doi.org/10.1007/978-94-009-4109-0 http://doi.org/10.1007/978-94-009-4109-0 http://doi.org/10.1007/s11004-005-7383-7 https://doi.org/10.1007/978-94-007-5815-5 https://doi.org/10.1007/978-94-007-5815-5 https://doi.org/10.1016/j.geoderma.2010.09.005 https://doi.org/10.1016/j.geoderma.2010.09.005 https://doi.org/10.1016/j.geoderma.2004.03.004 https://doi:10.4154/gc.2019.02 http://doi.org/10.1016/j.cageo.2012.06.012 http://doi.org/10.1016/j.cageo.2012.06.012 https://doi.org/10.1016/j.gexplo.2014.03.022 https://doi.org/10.1016/j.gexplo.2014.03.022 http://doi.org/10.1144/gsl.sp.2006.264.01.11 http://doi.org/10.1144/gsl.sp.2006.264.01.11 http://doi.org/10.1016/j.aeolia.2016.04.006 https://doi.org/10.4154/gc.2023.08 https://doi.org/10.1016/j.gexplo.2024.107473 https://doi.org/10.1016/j.gexplo.2024.107473 http://doi:10.3390/rs14205169 https://doi.org/10.1016/j.gsf.2015.11.009 https://doi.org/10.1016/j.gexpl o.2012.02.006 https://doi.org/10.1016/j.gexpl o.2012.02.006 https://doi.org/10.1186/s12932-019-0065-z https://doi.org/10.1186/s12932-019-0065-z https://www.hgi-cgs.hr/geoloske-karte/ https://doi.org/10.3389/feart.2022.1055435 https://doi.org/10.3389/feart.2022.1055435 g eologia c roatica 171pjanić et al.: geochemical map of croatia – key findings and legacy of geochemical mapping in the pannonian basin pk – in croatian].– in: velić, i. & vlahović, i. (eds.): tumač za ge­ ološku kartu hrvatske m 1:300.000 [explanatory notes for the geological map of croatia m 1:300,000– in croatian].– croatian geological sur­ vey, 11–13. jenny, h. (1941): factors of soil formation: a system of quantitative pedo­ logy.– dover publications, new york, 271 p. köppen, w. (1918): klassifikation der klimate nach temperatur, niederschlag und jahreslauf, petermanns geographische mitteilungen, 64, 193–203. kovačević galović, e., ilijanić, n., peh, z., miko, s. & hasan, o. (2012): geochemical discrimination of early palaeogene bauxites in croatia.– geologia croatica, 65, 53–65. https://doi.org/10.4154/gc.2012.04 mert, m.c., filzmoser, p., endel, g. & wilbacher, i. (2018): com­ positional data analysis in epidemiology.– statistical methods in medical research, 27/6, 1878–1891. https://doi.org/10.1177/0962280216671536 miko, s., halamić, j., peh, z. & galović, l. (2001): geochemical ba­ seline mapping of soils developed on diverse bedrock from two regions in croatia.– geologia croatica, 54, 53–118. mutić, r. (1975): sedimentološka ispitivanja naslaga lesa iz okolice vinko­ vaca, našica i valpova [sedimentological studies of loess deposits from the vicinity of vinkovci, našice and valpovo– in croatian].– geološki vjesnik, 28, 269–286. oreščanin, v., lulić, s., pavlović, g. & mikelić, l. (2004): granu­ lometric and chemical composition of the sava river sediments upstream and downstream of the krško nuclear power plant.– environmental geo­ logy (berlin), 46, 605–613. https://doi.org/10.1007/s00254­004­1066­4 pamić, j. & lanphere, m. (1991): hercynian granites and metamorphic rocks from the papuk, psunj, krndija and the surrounding basement of the pannonian basin (northern croatia, yugoslavia).– geologija, 34, 81– 253. panagos, p. (2006): the european soil database.– geo: connexion, 5/7, 32–33. pavelić, d. & kovačić, m. (2018): sedimentology and stratigraphy of the neogene rift­type north croatian basin (pannonian basin system, cro­ atia): a review.– marine and petroleum geology, 91, 455–469. https://doi. org/10.1016/j.marpetgeo.2018.01.026 pavlović, g., prohić, e. & tibljaš, d. (2004): statistical assessment of geochemical pattern in overbank sediments of the river sava, croatia.– environmental geology, 46, 132–143. https://doi.org/10.1007/s00254­004­ 1019­y pavlović, p., marković, m., kostić, o., sakanc, s., đorđević, d., perović, v., pavlović, d., pavlović, m., čakmak, d., ja­ rić, s., paunović, m. & mitrović, m. (2019): evaluation of poten­ tially toxic element contamination in the riparian zone of the river sava.– catena, 174, 399–412. https://doi.org/10.1016/j.catena.2018.11.034 pawlowsky­glahn, v. & egozcue, j.j. (2006): compositional data and their analysis: an introduction.– in: buccianti, a., mateu­fi­ gueras, g. & pawlowsky­glahn. v. (eds.): compositional data analysis in the geosciences: from theory to practice. geological society london, special publication, 264, 1–10. pawlowsky­glahn, v., egozcue, j.j. & tolosana­delgado, r. (2007): lecture notes on compositional data analysis.– universitat de gi­ rona, girona, 96 p. peh, z. & halamić, j. (2010): discriminant function model as a tool for classification of stratigraphically undefined radiolarian cherts in ophioli­ te zones.– journal of geochemical exploration, 107, 30–38. https://doi. org/10.1016/j.gexplo.2010.06.003 peh, z. & kovačević galović, e. (2014): geochemistry of istrian lower palaeogene bauxites—is it relevant to the extent of subaerial exposure during cretaceous times?– ore geology reviews, 63, 296–306. https:// doi.org/10.1016/j.oregeorev.2014.05.020 peh, z. & kovačević galović, e. (2016): geochemistry of lower pala­ eogene bauxites–unique signature of the tectonostratigraphic evolution of a part of the croatian karst.– geologia croatica, 69/2, 269–279. https:// doi.org/10.4154/gc.2016.24 peh, z., šajn, r., halamić, j. & galović, l. (2008): multiple discrimi­ nant analysis of the drava river alluvial plain sediments.– environmen­ tal geology, 55/7, 1519–1535. https://doi.org/10.1007/s0025 4­007­1102­2 peh, z., miko, s. & hasan, o. (2010): geochemical background in soils: a linear process domain? an example from istria (croatia).– environmen­ tal earth sciences, 59/6, 1367–1383. https://doi.org/10.1007/s12665­009­ 0125­2 phillips, j.d. (1998): on the relation between complex systems and the fa­ ctorial model of soil formation.– geoderma, 86, 1–21. https://doi. org/10.1016/s0016­7061(98)00054­8 phillips, j.d. (2002): global and local factors in earth surface systems.– eco­ logical modelling, 149/3, 257–272. https://doi.org/10.1016/s0304­ 3800(01)00461­6 phillips, j.d. (2017): soil complexity and pedogenesis.– soil science, 182, 117–127. https://doi.org/10.1097/ss.0000000000000204 poch, r.m., galović, l., husnjak, s., martinčević lazar, j., hećej, n., ružičić, s., pjanić, a., álvarez, d., beerten, k., gajić, r., stejić, p. & pandurov, m. (2024): soil formation and en­ vironmental reconstruction of a loess­paleosol sequence in zmajevac, cro­ atia.– catena, 247, 108507. https://doi.org/10.1016/j.catena.2024.108507 reimann, c., filzmoser, p., garrett, r.g. & dutter, r. (2008): statistical data analysis explained: applied environmental statistics with r.– john wiley & sons, new york, 368 p. http://doi.org/10.1002/ 9780470987605 reimann, c., birke, m., demetriades, a., filzmoser, p. & o’connor, p. (eds.) (2014): chemistry of europe’s agricultural soils – part a. methodology and interpretation of the gemas data set.– geolo­ gisches jahrbuch (reihe b 102), schweizerbarth, hannover, 528 p. rock, n.m.s. (1988): lecture notes in earth sciences, vol 18.– in: numeri­ cal geology. springer berlin, heidelberg, 427 p. https://doi.org/10.1007/ bfb0045143 romić, m. & romić, d. (2003): heavy metals distribution in agricultural topsoils in urban area.– environmental geology, 43, 795­805. https://doi. org/10.1007/s00254­002­0694­9 romić, m., romić, d., dolanjski, d. & stričević, i. (2004): heavy metals accumulation in topsoils from the wine­growing regions, part 1. factors which control retention.– agriculturae conspectus scientifi­ cus, 69/1, 1–10. starijaš, b., gerdes, a., balen, d., tibljaš, d. & finger, f. (2010): the moslavačka gora crystalline massif in croatia: a cretaceous heat dome within remnant ordovician granitoid crust.– swiss journal of ge­ osciences, 103/1, 61–82. https://doi.org/10.1007/s00015­010­0007­3 statsoft inc. (2006): statistica (data analysis software system), version 7.1. www.statsoft.com. strahler, a.n. (1980): systems theory in physical geography.– physical geography, 1/1, 1–27. https://doi.org/10.1080/02723646.1980.10642186 šajn, r., halamić, j., peh, z., galović, l. & alijagić, j. (2011): as­ sessment of the natural and anthropogenic sources of chemical elements in alluvial soils from the drava river using multivariate statistical met­ hods.– journal of geochemical exploration, 110/3, 278­289, https://doi. org/10.1016/j.gexplo.2011.06.009 šorša, a. (2009): gis – data processing and graphical presentation.– in: halamić, j. & miko, s. (eds.): geochemical atlas of the republic of croatia.– croatian geological survey, zagreb, 29. šorša, a., peh, z. & halamić, j. (2018a): geochemical mapping the ur­ ban and industrial legacy of sisak, croatia, using discriminant function analysis of topsoil chemical data.– journal of geochemical exploration, 187, 155–167. https://doi.org/10.1016/j.gexplo.2017.07.014 šorša, a., miler, m., gosar, m. & halamić, j. (2018b): follow­up geochemical studies and mineralogical investigations by scanning ele­ ctron microscopy/energy dispersive spectroscopy (sem/eds) of soil samples from the industrial zone of sisak, croatia.– journal of geoche­ mical exploration, 187, 168–183. https://doi.org/10.1016/j.gexplo.2017. 07.015 https://doi.org/10.4154/gc.2012.04 https://doi.org/10.1177/0962280216671536 https://doi.org/10.1016/j.marpetgeo.2018.01.026 https://doi.org/10.1016/j.marpetgeo.2018.01.026 https://doi.org/10.1007/s00254-004-1019-y https://doi.org/10.1007/s00254-004-1019-y https://doi.org/10.1016/j.catena.2018.11.034 https://doi.org/10.1016/j.gexplo.2010.06.003 https://doi.org/10.1016/j.gexplo.2010.06.003 https://doi.org/10.1016/j.oregeorev.2014.05.020 https://doi.org/10.1016/j.oregeorev.2014.05.020 https://doi.org/10.4154/gc.2016.24 https://doi.org/10.4154/gc.2016.24 https://doi.org/10.1007/s0025 4-007-1102-2 https://doi.org/10.1007/s12665-009-0125-2 https://doi.org/10.1007/s12665-009-0125-2 https://doi.org/10.1016/s0016-7061(98)00054-8 https://doi.org/10.1016/s0016-7061(98)00054-8 https://doi.org/10.1016/s0304-3800(01)00461-6 https://doi.org/10.1016/s0304-3800(01)00461-6 https://doi.org/10.1097/ss.0000000000000204 https://doi.org/10.1016/j.catena.2024.108507 http://doi.org/10.1002/9780470987605 http://doi.org/10.1002/9780470987605 https://doi.org/10.1007/s00254-002-0694-9 https://doi.org/10.1007/s00254-002-0694-9 https://doi.org/10.1007/s00015-010-0007-3 http://www.statsoft.com https://doi.org/10.1080/02723646.1980.10642186 https://doi.org/10.1016/j.gexplo.2011.06.009 https://doi.org/10.1016/j.gexplo.2011.06.009 https://doi.org/10.1016/j.gexplo.2017.07.014 https://doi.org/10.1016/j.gexplo.2017.07.015 https://doi.org/10.1016/j.gexplo.2017.07.015 g eo lo gi a c ro at ic a 172 geologia croatica 78/2 tolosana­delgado, r. (2012): uses and misuses of compositional data in sedimentology.– sedimentary geology, 280, 60–79. https://doi.or­ g/10.1016/j.sedgeo.2012.05.005 velić, i. & vlahović, i. (eds.) (2009): tumač geološke karte republike hrvatske 1: 300.000 [explanatory notes for geological map of the republic of croatia, scale 1:300,000– in croatian].– croatian geological survey, 141 p., zagreb. zaninović, k., gajić­čapka, m., perčec tadić, m., vučetić, m., milković, j., bajić, a., cindrić, k., cvitan, l., katušin, z., kaučić, d., likso, t., lončar, e., lončar, ž., mihajlović, d., pandžić, k., patarčić, m., srnec, l. & vučetić, v. (2008): klimatski atlas hrvatske 1961–1990, 1971–2000. [climate atlas of croatia 1961–1990, 1971–2000– in croatian].– croatian meteorological and hydrological service, zagreb, 200 p. web sources: corine land cover (2018): clc2018 raster data of the pannonian ba­ sin.– european environment agency (eea). available at: http://www. eea.europa.eu. accessed on: april 1st, 2024. https://doi.org/10.1016/j.sedgeo.2012.05.005 https://doi.org/10.1016/j.sedgeo.2012.05.005 http://www.eea.europa.eu http://www.eea.europa.eu 2022 | 75/1 | 145–163 | 16 figs. | 5 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society geological, geochemical and fluid inclusion investigations on the duna pb-ba-(ag) deposit, central alborz, north central iran alireza sadeghi1, nima nezafati2*, saeid hakimi-asiabar3 and alireza ganji4 1 islamic azad university, science and research branch, department of earth sciences, tehran, iran; (asadeghi.1345@gmail.com) 2 department of earth sciences, islamic azad university, science and research branch, tehran, iran; german mining museum, department of archaeometallurgy, bochum, germany (*corresponding author; nima.nezafati@gmail.com, nima.nezafati@bergbaumuseum.de) 3 islamic azad university, lahijan branch, department of geology, lahijan, iran; (saeid.h.asiabar@gmail.com) 4 islamic azad university, lahijan branch, department of geology, lahijan, iran; (ar_ganji2000@yahoo.com) doi: 10.4154/gc.2022.08 abstract the duna pb-ba-(ag) mine is located ca. 155 km north of tehran in the central alborz structural zone, northern iran. the ore mineralization occurs as stratabound, epigenetic, e-w and wswene trending veins and veinlets in fracture-controlled as well as massive and open-space filling textures within a permian dolomitic limestone host rock. field observations as well as mineralogical and petrographic studies show dolomitization, silicification and possibly haematisation in the host rock. in the mineralization zone, galena and barite are the main minerals, followed by pyrite, quartz, chalcopyrite, tetrahedrite, sphalerite, calcite and supergene minerals such as covellite, malachite, azurite, cerussite, anglesite, and fe-oxides. the chemical analyses of the highgrade ore samples show an average grade of 18.66 wt. % for pb, 19.99 wt. % for ba, and 120 ppm for ag together with substantial quantities of zn (0.15 wt. %), as (690 ppm), cu (0.86 wt. %), sb (0.25 wt. %), and sr (0.56 wt. %). the amount of silver in some samples from the tunnel and discordant layers is up to 7030 ppm. the positive eu/eu ⃰ratio and the weak negative ce/ce⃰ anomaly in the ore samples were most likely inherited from magmatic water. the presence of minerals such as pyrite and chalcopyrite together with the co-precipitation of sphalerite and chalcopyrite suggest a high-temperature for mineralizing fluids. the homogenization temperatures of fluid inclusions from barite in concordant layers span between 135 and 165 ºc with salinities between 18.54 and 23.65 wt. % nacl equivalent, while the homogenization temperatures of fluid inclusions from barite of discordant layers span between 113 and 285 ºc with salinities between 7.34 and 23.65 wt. % nacl equivalent. the structural, geological, geochemical, and mineralogical studies together with the paragenesis of the ore minerals and fluid inclusion data allow consideration of the duna pb-ba-(ag) mine as a two stage mineralization scenario; 1st stage /older/mvt-type (early cimmerian tectonic phase), and the second stage/younger/irish-type (laramide orogenic movements). the structural data, high temperature of the fluid inclusions, positive eu/eu ⃰ ratio and high silver content, especially in the discordant layers, indicate the involvement of a magmatic water mixed with meteoric and connate fluids comparable to the irishtype mineralization in the second stage, which formed along brecciated zones of the thrust faults. the second stage of mineralization was most likely influenced by the akapol granitoid intrusive mass, which overprinted the 1st stage/older/mvt-type. article history: manuscript received september 01, 2020 revised manuscript accepted november 22, 2021 available online february 11, 2022 keywords: carbonate-hosted mineralization, fluid mixing, irish-type ore deposit, mississippi valley-type (mvt) ore deposit, ree 1. introduction the alborz mountain range with a general e-w trend, 1000 km length and a width of 50 to more than 100 km between the caspian sea and the iranian plateau resulted from the collision of the iran and turan plates (fig. 1b) in the late triassic in northern iran (aghanabati, 2004). the alborz zone was affected by several successive tectonic events, including the early cimmerian orogeny in the lower triassic to cretaceous-tertiary compression event (allen et al., 2003; golonka, 2004; guest et al., 2006; horton et al., 2008; zanchi et al., 2009; mirnejad et al., 2015 ). folding and thrusting of palaeozoic to mesozoic sedimentary sequences in the alborz host a variety of pb and zn deposits such as the middle permian limestone (ruteh formation), lower-middle triassic dolomite and middle-late triassic limestone (elika formation), jurassic limestone (lar and dalichai formations), and cretaceous limestone and dolomite (mirnejad et al., 2015). metals were thought to have been sourced from the upper palaeozoic rock units of the alborz range (holzer & momenzadeh, 1969; samanirad, 1999). previous studies of model pb isotopes and plumbotectonics (zartman & doe, 1981) show that most of the pb-zn deposits in the alborz and central iran were in contact with mantle and crust and the pb isotopic ratios of galena mineralization in the duna mine are similar to the pb-zn deposits of the urumiehdokhtar volcanic belt and are related to the cenozoic magmatic activity (hassanzadeh et al., 2002). the alborz zone is principally a sedimentary zone with some magmatic features, where sedimentary units from late precambrian to neogene ages are exposed (aghanabati, 2004). based on the geological investigations, the alborz zone is one of the most promising areas for lead and zinc mineralization in iran. containing more lead than zinc and more lead minerals than other sulfide minerals, being hosted by permian to tertiary rocks mostly of carbonaceous origin (especially in the ruteh carbonate formation of permian age), being mostly surrounded by volcanic rocks, tuff, and intrusive masses, and having low copper and in most cases high silver contents are among the features that characterize the pb-zn deposits of central alborz (ghorbani, 2013). g eo lo gi a c ro at ic a geologia croatica 75/1146 the duna pb-ba-(ag) mine (lat 36º 7’ 36º 9’ n, long 51º 20’51º 25’ e), with probable ore reserves of 0.5 to 1 mt @ 6.7% pb and 1400 ppm ag (ghorbani, 2013), is one of the most complex deposits of the alborz tectonic zone, which is situated in northern tehran province, about 155 km north of tehran, iran (fig. 1a). lead and zinc usually occur here as sulfide minerals; mainly galena and sphalerite in three major types of vms, sedex, and mvt deposits, as well as in distal skarn deposits, intermediatetype epithermal deposits, etc. (davidheiser-kroll, 2014). there are different beliefs regarding irish-type dependency and similarity to sedex and mvt deposits. mississippi valley-type (mvt) deposits are epigenetic, stratabound, carbonate-hosted sulphide bodies, composed predominantly of zinc and lead, bound in sphalerite and galena (paradis et al., 2007) and some irish-type deposits are sub-types of mvt deposits (hitzman & beaty, 1997). they are located in carbonate platform settings, typically in relatively undeformed orogenic foreland rocks, commonly in foreland thrust belts, and rarely in rift zones (leach & sangster, 1993). the irish-type deposits are stratabound, structurally controlled, carbonate-hosted, pb-zn deposits that have sedimentary exhalative (sedex) and/or mvt characteristics (hitzman & beaty, 1997). irish-type deposits are considered to have been formed by ore-forming processes similar to those of sedex deposits but, because carbonate platforms are highly soluble in mildly acidic ore fluids, ores were also deposited in the hydrothermal karst system (e.g. dissolution voids, collapse breccias) (goodfellow & lydon, 2007). in case of the duna mine, holzer and momenzadeh (1969) consider this mineralization as an example related to the permian volcanogenic origin in central alborz. in the present study, geochemistry of the major and the rare earth elements (of the ore, barite, host and igneous rock), mineralogy, and fluid inclusion studies as well as structural geology together with the review of previous studies were used to determine the genetic model and the type of mineralization in the duna mine. these also resulted in better understanding of the role of plutonic bodies in the mineralization, the source of mineralizing fluids, and the role of some specific fault sets (rather than others) in the mineralization of the duna mine. 2. geological setting the central alborz zone runs from west to east along the southern coast of the caspian sea (alavi 1991). the duna pb-ba-(ag) mine is located in the central alborz zone and between two major faults with a general e-w trend, including the kandovan thrust fault with a length of about 100 km in the south and the azadkuh fault with a length of about 30 km in the north (fig. 1c). the distance between kandovan and azadkuh faults from the duna mine is less than 1000 and 300 metres, respectively. guest et al. (2006) have divided the central alborz into the northern alborz zone, thin-skinned zone, southern zone, and the taleghan range (fig. 1c). in the northern zone, deformation intensifies presumably southwardfrom the northern foothills to the range crest. this zone is composed of w-e striking faults and folds. the northern zone was deformed during the laramide orogeny (hakimi asiabar & bagherian, 2018). the duna mine is located in the thin-skinned zone, confined between the azadkuh and kandovan figure 1. a , c) location of the duna mine in the central alborz structural zone (modified after guest et al., 2006). b) simplified structural unit of iran with the arabian plate in the south and the turan plate in the north (after berberian & king, 1981). g eologia c roatica sadeghi et al.: geological, geochemical and fluid inclusion investigations on the duna pb-ba-(ag) deposit, central alborz, north central iran 147 faults. the thin-skinned zone shows strong evidence of late miocene deformation. the thrust faults of the thin-skinned zone generally strike northwest-southeast, whereas the late miocene microdiorite dyke swarm that intrudes into the thin-skinned zone cuts across but is slightly offset by the thrusts, and strikes northeast-southwest (guest et al., 2006). the southern zone comprises nw-se trending thrusts, synclines, and anticlines, which were refolded, and formed an older set of folds that trend roughly ne-sw (guest et al., 2006). most of the taleghan range is composed of a large, open, upright, gently west-plunging anticline with its limbs truncated by the high-angle taleghan fault zone, along with its northern flank, and by the mosha thrust, along with its southern flank (guest et al., 2006). the duna carbonate-hosted lead mine is situated in an anticline and is part of an uplift (or pop-up) tectonic structure with an asymmetric rhombus shape (mcclay & bonora, 2000) that was formed by reverse tectonic movements and performance of the kandovan and azadkuh faults. the duna anticline structure consists of palaeozoic to quaternary rocks (fig. 2). the palaeozoic units are composed of sandstone, siltstone, and red shale of lower permian rocks (dorud formation pdr) as well as the dolomitic limestone of the figure 2. a geological map of the duna mine (hakimi asiabar, 2019). a-a' and b-b' sections from tunnel (second stage/younger/irish-type) and d-d' section from open pit (mostly 1st stage/older/mvt). g eo lo gi a c ro at ic a geologia croatica 75/1148 middle permian which is composed of layers of micritic and bituminous limestone of the ruteh formation (pru). the ruteh formation is the main host of the mineralization in the duna pbba-(ag) mine. after the sedimentation of the ruteh formation, the sea retreated in most parts of the central alborz and volcanic rocks including dolerite, olivine basalt, trachyandesite and andesibasalt (ranging from 50 to 80 metres in thickness) covered some areas (aghanabati, 2004). it was then that the nessen formation (pn) comprising of shale and sandstone was formed in the upper permian. the mesozoic rocks of the study area are composed of lower triassic carbonate rocks, grey dolomitic limestone, and cream dolostone of the elika formation (tre) that are unconformably covered by the late triassic to middle jurassic shale, sandstone, and conglomerate of the shemshak formation (j.sh). the early cimmerian orogenic movements caused an angular unconformity between the jurassic shemshak and the triassic elika formations in the alborz mountain range (annells et al., 1975; allen et al., 2003; baharfiruzi & shafeii, 2005) including the study area. during the upper cretaceous, deposition of the sedimentary rock units of the northern part of the study area began with benthic limestone and gradually changed into hemipelagic to pelagic sediments (modaresnia et al., 2012). the late cimmerian event has caused angular unconformities between jurassic and cretaceous sediments of the thin-skinned and southern folded zones of the alborz range (annells et al., 1975; baharfiruzi & shafeii, 2005). neogene sediments crop out in the intermontane basins and in the southern margin of the duna anticline. they include conglomertable 1. the icp-ms analysis results of the duna mine samples in ppm (ore, hr: host rock, ir: igneous rock, brt: barite). dis: discordant veins (mostly second stage/ younger/irish-type); con: concordant veins (mostly 1st stage/older/mvt-type); dol: dolomite; mel: melaphyre unit. dsa8, 14 dsa28 dsa24 dsa6 dsa26 dsa5 dsa17 dsa7 dsa4 dsa2b dsa1 sample brt (dis) ir (mel) ir (mel) ir (mel) hr (dol) hr (dol) ore (con) ore (con) ore (dis) ore (con) ore (dis) rock type ag 156.8 264.3 18.9 76 86.3 0.7 1.7 0.4 5.7 0.8 16.8 al % 0.09 0.26 0.01 0.09 0.17 7.29 3.4 6.92 7.96 6.89 0.29 as 20.5 3328 49.7 12.9 39.3 7.8 2.6 15 16.7 2.4 34.9 ba 9.545 24.50% 54.35 1232 1.20% 364 52 327 103 104 31.50% be 0.3 0.3 0.3 0.3 0.3 0.7 1.4 1.4 1.4 0.6 0.4 bi 0.6 0.8 0.2 0.3 0.7 0.2 <0.1 0.3 <0.1 <0.1 0.25 ca 0.12 0.36 0.03 2.39 5.79 6.32 9.16 2.04 1.49 5.63 6.9 cd 12.6 57.4 13.7 <0.1 2.6 <0.1 0.1 <0.1 0.3 <0.1 3.2 co <1 <1 <1 <1 1.2 47.5 38 50 2.8 37.4 2.7 cr 11 35 9 25 12 108 289 125 14 176 19 cs <0.5 <0.5 <0.5 0.6 <0.5 3.9 1.2 3.1 1.2 0.8 0.55 cu 834 4.16% 497 77 203 246 5 360 12 45 244.5 fe % 0.09 0.41 0.03 0.44 0.95 7.69 10.01 14.01 2.21 7.02 0.5 hf <0.5 <0.5 <0.5 <0.5 <0.5 2.96 2.01 2.62 11.7 1.83 <0.5 in <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 k <100 164 <100 168 <100 4946 1.10% 1.47% 1.47% 3080 940 li <1 <1 <1 2 3 63 <1 31 <1 17 1.4 mg 672 1156 159 1.21% 3.51% 2.93% 4.44% 2.75% 2011 5.09% 4.10% mn 50 95 54 269 675 667 1854 565 332 1037 425 mo <0.1 0.8 <0.1 0.8 2.3 <0.1 <0.1 <0.1 0.9 <0.1 0.08 na 314 336 303 380 361 1.73% 7759 1.73% 4.49% 1.40% 393 nb 1.9 1.6 1.5 1.7 1.4 12.3 14 24.4 158.8 14.9 1.55 ni 4 5 1 3 6 74 58 74 8 119 4.8 p 224 367 52 69 108 904 730 1438 168 485 113 pb 54.10% 347 3238 5731 38.50% 56 80 45 304 43 4660 rb 2 3 <1 1 2 18 25 45 32 7 3.4 s 10.80% 6.14% 13.10% 1121 5.71% 98 80 1378 135 56 7.60% sb 566 1.10% 57.9 32.7 75 8.4 0.6 6.1 1.6 <0.5 136.7 sc <0.5 <0.5 <0.5 <0.5 1.18 29.4 13.5 32.4 <0.5 33.8 0.8 se 2.81 5.53 1.01 0.68 0.59 1.78 2.9 2.21 3.15 2.54 0.4 si % 0.96 20.2 0.52 40.3 8.47 21.3 12.5 21.64 29.86 22.6 4.7 sn 0.6 0.7 0.5 0.8 0.5 1.4 1 1.4 9.8 0.8 0.55 sr 501.3 1.20% 1.51% 65.3 400.6 141.5 85 82.4 77 151 1.30% ta 0.54 0.37 0.49 0.32 0.31 1.5 0.72 1.7 10.73 0.81 0.31 te <0.1 1.21 0.19 0.3 0.48 0.38 0.4 0.25 0.14 0.23 0.77 th 1.3 1.26 1.06 1.06 1.25 2.5 0.29 3.12 10.97 <0.1 1.17 ti <10 <10 <10 <10 <10 9853 7511 1.10% 726 6448 261 u 2.02 15.2 0.3 1 4.5 0.3 0.3 0.5 2.3 0.2 1.15 v 15 24 11 33 31 182 138 258 11 195 31 w <1 <1 <1 <1 <1 <1 <1 <1 1.8 <1 <1 zn 2188 1267 4170 10 94 132 36 70 114 58 581.5 zr <5 <5 <5 <5 <5 81 83 97 755 63 5 zn/(zn+pb) 0.01 0.79 0.57 0.01 0.0002 0.71 0.31 0.61 0.28 0.58 0.11 g eologia c roatica sadeghi et al.: geological, geochemical and fluid inclusion investigations on the duna pb-ba-(ag) deposit, central alborz, north central iran 149 ates and fine clastic deposits which are mostly red in colour. this sequence lies unconformably on palaeogene volcanic and sedimentary rock sequences. quaternary deposits are widespread on the caspian plain and are preserved as patches in many places including the intermontane basins. in addition to some melaphyre rocks, the akapol intrusive mass (4 km south of duna) and the alamkuh intrusive body (300 metres north of the duna mine) indicate some past magmatic activities in the area. 3. sampling and analytical techniques field geology and sampling were conducted in three stages on a 3 km2 area in the summer and autumn of 2017 as well as in summer 2018. twenty-eight samples from the concordant/1st stage/ older/ mvt-type and discordant/second stage/younger/irish-type of mineralization were selected from different parts of the duna mine. thirteen samples from the orebodies, three samples from the host rock, five samples from massive barite and seven samples from the igneous rocks were taken from different points and horizons. the location of these samples have been plotted on the 1:1000 geologic map (fig. 2). in order to determine the concentrations of trace and rare earth elements, 12 samples were collected from various locations including five samples of mineralized limestone from concordant/1st stage (dsa7 and dsa17) and discordant/second stage of mineralization (dsa1, dsa2b and dsa4), two samples of dolomitic host rocks (dsa5, dsa26), three samples of igneous rocks (dsa6, dsa24, and dsa28), as well as two samples of massive barite (dsa8 and dsa14) from the concordant/second stage. all samples were analyzed by icp-ms (inductively coupled plasma-mass spectrometer) method (in ppm) at the zarazma mineral studies company, iran (table 1 & table2), using a perkin 9000 drce model, following a near-total digestion applying four acid digestion including hf, hcl, hclo4 and hno3. the various steps of the sample preparation include drying at 120°c, crushing to less than 4 mm, and pulverizing to 75 µm and analyzed under high temperature and multi acid digestion. the petrographic study was performed on 29 polished-thin sections at the mineralogical laboratory of the science and research branch of the islamic azad university. ore mineralogy studies were conducted on eleven sections at the mineralogical laboratory of the geological survey of iran using a polarizing microscope. one ore sample from the discordant/second stage/ younger/irish-type (code dsa1) was selected and analyzed by the electron probe micro analysis (epma) method at 12 points on its tetrahedrite, galena and sphalerite minerals. analyses were performed in the iranian mineral processing research center (imprc), karaj, iran. the epma was performed for a more detailed study on the ag and other trace elemental contents of the ore sample of duna mine. for this purpose, a epma cameca with sx100, accelerating voltage of 20 kev, a beam current of 20 na, a beam size of 5 μm, and a detection limit 500 ppm was used. fluid inclusion samples were collected from open pit through the ore-bearing veins and tunnels from discordant/second stage/ younger/irish-type (codes dsa4 and dsa8) and concordant/1st stage/older/mvt of mineralization. microthermometric analyses were performed to obtain a preliminary estimate of the temperatures and salinities of the ore-forming fluids. in this fluid inclusion study, we used standard techniques (steele et al., 2011) and a linkam model thms 600 heating-freezing stage mounted on a zeiss, axioplan 2, imaging microscope with a temperature range between -196 ºc to +600 ºc, at the iran mineral processing research center (imprc), karaj, iran. this stage is equipped with two controllers, heating (tp94) and cooling (lnp), a nitrogen tank (for pumping nitrogen for freezing) and a water tank (for using the device at high temperature). the accuracy is estimated to be ±0.2 ºc on freezing (n-hexane, melting point: -94.3 ºc) and ±0.6 ºc on heating (cesium nitrate, melting point: +414 ºc). 4. ore deposit geology 4.1. structural geology and ore bodies mineralization at the duna pb-ba-(ag) mine has been structurally controlled by the duna anticline and faults and has chemically been affected by bituminous layers, dolomitic horizons, and impermeable volcanic rocks of permian age. the structure of the duna pb-ba-(ag) mine is characterized by a horizontal to overturned fold with an axis length of about 6 km in an e-w trend (figs. 2, and 3a, b). in polyorogenic systems, structural controls table 2. the ree analysis results (in ppm) of the investigated samples from the duna mine including ore, host rock (hr), igneous rock (ir) and barite (brt), akapol intrusive (ak), bdl: below detection limit; dis: discordant veins (mostly second stage/younger/irish-type); con: concordant veins (mostly 1st stage/older/mvt-type); dol: dolomite; mel: melaphyre unit. a1-a2dsa8,14dsa6,24,28dsa5,26dsa17dsa7dsa4dsa2bdsa1sample ak (intrusive) brt (dis) ir (mel) hr (dol) ore (con) ore (con) ore (dis) ore (con) ore (dis) rock type 63.41.35215<1<1<11<1la 1062.311333.5<1<1<12<1ce 10.270.511.44.480.380.270.230.630.26pr 33.71.0542.119.70.6<0.5<0.51.3<0.5nd 4.451.627.834.740.180.53.222.280.19sm 1.300.911.781.68<0.10.192.261.44<0.1eu 3.320.696.434.190.690.60.560.730.6gd 0.39<0.10.950.7<0.1<0.1<0.1<0.1<0.1tb 1.830.2163.740.190.120.080.180.12dy 0.28bdlbdlbdlbdlbdlbdlbdlho 0.78<0.053.461.76<0.05<0.05<0.05<0.05<0.05er 0.1<0.10.490.25<0.1<0.1<0.1<0.1<0.1tm 0.71<0.054.52<0.05<0.05<0.05<0.05<0.05yb 0.1<0.10.450.2<0.1<0.1<0.1<0.1<0.1lu 0.341.190.653.543.85eu/eu* 4.150.931.080.450.58ce/ce* g eo lo gi a c ro at ic a geologia croatica 75/1150 figure 3. the relationship between the mineralization, structure, and host rock in the duna mine. a) view of folding (anticline) in the open pit of the duna mine (view to the east); b) the cross section (dd’) of the geological map and mineralization position in the dorud and ruteh formations; c) field photograph showing the top fold (anticline) in the eastern district of the duna mine (view to the south). pdr-dorud formation; pru-ruteh formation; pn-nessen formation; pab-melaphyre unit; jsh-jurassic formation; q-quaternary; tre-elika; bitu-bituminous limestone. g eologia c roatica sadeghi et al.: geological, geochemical and fluid inclusion investigations on the duna pb-ba-(ag) deposit, central alborz, north central iran 151 of ore bodies are often not easy to understand because the multiple phases of mineralization and the relationship between structures and ore bodies are not clear. the geological cross-section of the field observations (fig. 2) displays the relationship between mineralized zones, bedding of host rocks, fractures, and structural forms. the duna mining area is divided by f1 and f2 faults into the eastern, middle, and western blocks. the permian rock units override to the north by these faults. the mineralization in the duna mine has predominantly occurred in the dolomitic ruteh formation (middle permian) but also to some extent in the dorud formation (lower permian) (holzer & momenzadeh, 1969), which are both exposed at the core of the duna anticline (figs. 2, and 3b). the lower part of the dolomitic ruteh formation is confined to a fault boundary while its upper part with highest mineralization is in contact with igneous rocks and bituminous limestone (fig. 3c) (hakimi asiabar, 2019). it seems that bituminous limestone containing organic matter has changed the eh-ph conditions of the mineralizing fluids and therefore enriched mineralization in these parts. in the eastern part of the mine, many extracting tunnels have been dug at the upper boundary of the mineralized ruteh formation (fig. 3c). the ruteh and durod formations are exposed at the core of the duna anticline (fig. 2, cross sections; aa’, bb’, cc’, and dd’). the tunnels are located in the central and eastern part of the duna mine. most of the mineralized veins in the tunnels have a northwest-southeast and east-west trend and follow the path of steep faults. these sections indicate an asymmetric fold in the duna mine where most of the mineralization has occurred discordantly in the normal edge of the fold, in the dolomitic ruteh formation and its contact with melaphyre rocks (pab), which mostly indicates the second stage/younger/irish-type of mineralization. the section dd’ is located in the western part of the duna mine and in the position of the open pit. stratabound and stratiform mineralization of the copper-barite-lead slope can be seen throughout the contact of dolomitic ruteh formation and igneous rocks which are mostly indicative of the 1st stage/older/ mvt-type of mineralization. this stratabound mineralization has occurred in the faulted permian limestone and dolomitic rocks, which are overlain by andesitic basalt (pab) of the late permian (fig. 3b, c). the melaphyre unit (pab) is very dense and as an impermeable rock unit has acted like a confining barrier for limiting the mineralizing fluids in the top level of the duna mine. according to the rose diagrams (fig. 2), three major thrust fault generations were recognized in the study area (hakimi asiabar, 2019). most of the thrust faults of the geological map area have approximately w-e and wsw-ene directions. the first generation of thrust faults (due to the laramide orogeny), with wsw-ene strike is parallel to the major fold axis and dominated by reverse movement with a right-lateral component. approximately 65% of these faults hold mineralization in their brecciated zones (hakimi asiabar, 2019). most of these faults cropped out on the overturned layers of the duna anticline. the second group of fault sets (due to the pyrenean orogeny), with a nearly e-w trend and a reverse sense, is not parallel to the fold axis of the duna anticline and bedding surface of the layers. the third category of faults with an approximate trend of n30w to n40w intersects the first and second fault set. according to field observations, the first and second generations of thrust faults, contain mineralized zones, but the third fault set is barren and does not have any mineralized zone, which indicates overlapping of oreforming events predating the third faulting episode. each generation of thrust faults is usually accompanied with some strikeslip faults, diagonal to its trend. many mineralized veins and veinlets occurred along strike-slip faults as a result of folding processes affecting the layers (hakimi asiabar, 2019). the mineralization of concordant veins during the permian and triassic periods has occurred in the 1st stage/older/mvt while the mineralization along the first and second generations of thrust faults occurred in the second stage/younger/irish-type of mineralization. figure 4. hand specimens and field photograph of galena and barite mineralization in the duna mine. a) galena (gn) and barite (brt) mineralization in dolomitic host rock as open space filling of open pit/1st stage/older/mvt; b) mineralized vein of galena in hand specimen; c) disseminated barite in tunnel/ second stage/ younger/irish-type; d) hand specimen of high-grade galena. g eo lo gi a c ro at ic a geologia croatica 75/1152 4.2. ore mineralogy, texture and paragenesis based on the field observations, galena and barite are the most important minerals that have often occurred simultaneously (fig. 4a-d). mineralization in the duna mine occurred predominantly in the structural open-spaces of the dolomitic host rock. a massive mineralization of galena and barite with dimensions of more than 3 metres was formed as open space fillings, especially in shear zones (fig. 4a). the size of galena and barite mineralization in veins, veinlets, and in dissemination form (fig. 4b, c) is from about a few millimetres to a few tens of centimetres. a disfigure 5. photomicrographs of minerals in the duna mine. a) replacement tetrahedrite, sphalerite, and chalcophyrite in galena from the open pit; b) pyrite and sphalerite in galena from the open pit; c) aleration of galena to cerussite and covellite within the calcite and barite from the open pit; d) galena as a filled veinlet of fractures between quartz, calcite and barite from the tunnel; e) curved shape of galena from the tunnel; f ) haematite blades in barite from the open pit; g) alteration of crystalline euhedral pyrite to iron hydroxide and galena alteration from margins to cerussite from the tunnel; h) sphalerite inclusion in galena from the tunnel. brt-barite; cal-calcite; cp-chalcopyrite; cv-covellite; cal-calcite; gn-galena; hem-haematite; py-pyrite; qz-quartz; cer-cerrussite; sl-sphalerite; tt-tetrahedrite. figures a, b, c and f are from the open pit/mostly 1st stage/older/mvt and figures d, e, g and h are from the tunnel/second stage/younger/irish-type. symbols from whitney and evans, (2010). g eologia c roatica sadeghi et al.: geological, geochemical and fluid inclusion investigations on the duna pb-ba-(ag) deposit, central alborz, north central iran 153 seminated texture has occurred due to replacement and/or openspace filling. microscopic study of the samples collected from both concordant and discordant mineralization (fig. 5) demonstrates two stages; the mineralization in the first (older) stage of mississippi valley-type and the second (younger) stage of irish-type. based on the microscopic and macroscopic studies, galena is the main ore mineral while sphalerite, tetrahedrite, pyrite, and chalcopyrite comprise the accessory ore minerals. barite, dolomite, calcite and quartz are the gangue minerals. supergene minerals include fe-oxides, covellite, cerussite, anglesite, malachite, and azurite. 4.2.1. ore mineralogy, texture and paragenesis in the 1st stage/ older/mvt the concordant mineralization in the duna mine has mostly occurred in the 1st stage older/mvt. microscopic study of three samples collected from the concordant veins (dsa7; fig. 5b, dsa17; fig. 5e, and dsa5; fig. 5f) shows that galena is the main ore mineral in the 1st stage, that occurs as anhedral disseminated grains and open space filling (fig. 5b). the curved shape in some galena is a sign of mechanical (tectonic) pressures on the rock after formation of the ore mineral (fig. 5e). barite is the main gangue mineral that was deposited before and during the 1st stage /older/mvt (fig. 5f). in fig. 5b, sphalerite and chalcopyrite have a replacement state with each other and with galena. pyrite was formed before the main mineralization phase and its anhedral crystals are usually surrounded by galena (fig. 5b). pyrite was formed with open space filling and disseminated euhedral grains in the siliceous veins and veinlets at the 1st stage/younger/mvt of mineralization (fig. 5b). cerussite is formed around galena by secondary processes or supergene alteration (fig. 5e) while quartz was formed as microcrystalline euhedral grains (average 12µ in size) and also is scattered as siliceous veins in the host rock in the 1st stage. dolomite as a gangue mineral has occurred during dolomitization before the main mineralization stage. 4.2.2. ore mineralogy, texture and paragenesis in the second stage/younger/irish-type mineralisation the samples that were related to the second stage/younger/ irish-type of mineralization were collected from the discordant veins including the samples of dsa1 (fig. 5a, b), dsa4 (fig. 5 c), dsa12 (fig. 5h) and dsa13 (fig. 5g). dolomitic alteration in the host rock of the ruteh carbonate formation has produced more space for mineralization (fig. 6a). galena is the main ore mineral and occurs as anhedral disseminated grains (a few microns in size), open space filling (fig. 5a), and veinlets (up to 3 mm) (fig. 5d). galena is seen both undisturbed and altered from the margins into covellite and cerussite (fig. 5c, h). galena together with sphalerite, tetrahedrite, chalcopyrite and pyrite shows open space filling texture (fig. 5a). barite is a main gangue mineral that has filled voids, open spaces, cavities, and fractures in the host rock in the forms of layers, scattered plates, patches, and as a massive mineral with a few mm to 3 meters length. some metallic sulfide minerals are scattered among the barite grains. barite was deposited before and during the second stage/younger/irish-type of galena mineralization, although they have mostly occurred contemporaneously (fig. 5c, d, h). barite is often impregnated with calcium carbonate (fig. 5d). sphalerite together with tetrahedrite and chalcopyrite were mostly formed in the second stage/younger/ irish-type of mineralization (figs. 5a, g) that are in some cases surrounded by galena (fig. 5a, b, h). the frequency of sphalerite is about 5%. anhedral spots of sphalerite with dimensions of 2 to 20 mm are observed. sphalerite sometimes occurs as inclusions in galena (fig. 5g). co-precipitation of sphalerite and chalcopyrite occurred in the second stage/younger/irish-type of mineralization (fig. 5a). pyrite euhedral crystals are usually surrounded by galena (fig. 5g) and are also embedded in the barite as veinlet and open space fillings with other sulfide minerals. pyrite is a common sulfide mineral in many carbonate-hosted zn-pb deposits (leach et al., 2005). some pyrite grains have been transformed into iron hydroxides as a result of supergene alteration (fig. 5g). cerussite is formed around galena by secondary processes or supergene alteration in the second stage (fig. 5c). quartz is usually found in the hydrothermal breccia and brittle shear zones which shows the hydrothermal origin of some fluids. quartz veins that sometimes contain galena, pyrite, and carbonates were formed during the 1st stage/ older/mvt while hydrothermal quartz is formed in the second stage/younger/irishtype of mineralization (figs. 5d and 6a). silica has usually accompanied the hydrothermal fluids in the main mineralization stage and has manifested as silicification. calcite was formed in the late stage of galena and barite mineralization and surrounds these minerals (fig. 5d). the rock texture is composed of micrite. the secondary minerals in the 1st stage/ older/mvt and the second stage/younger/irish-type of mineralization include feoxy-hydroxides (figs. 5g and 6a), cerussite (fig. 5c, e, g), covellite (fig. 5c), anglesite (fig. 6a) malachite and azurite (fig. 6b), that were formed by oxidation processes of the sulfide minerals near the surface. anglesite is a secondary lead mineral, gray to yellow in colour and has occurred in the oxidized zone of the lead deposit and often surrounds galena. the paragenetic sequence of the duna pb-ba-(ag) mine is shown in figure 7. table 3. results of the microprobe analyses (epma) (wt. %) in an ore sample from a discordant vein (code dsa1). tt: tetrahedrite; gn: galena; sl: sphalerite and (*: below detection limit). mineral points pb zn ag as cu sb bi fe ga cd au s total tt 1 0.18 7.2 2.51 9.83 37.64 15.52 0.28 0.6 * * 0.04 26.57 100.4 tt 2 0.28 7.32 4.23 5.56 34.74 22.29 0.15 0.52 * * 0.03 25.37 100.5 tt 3 0.19 7.82 4.25 6.03 34.45 21.54 0.21 0.43 * * * 25.77 100.7 tt 10 0.08 8.32 2.13 11.09 37.14 15.13 0.14 0.66 * * * 26.02 100.7 gn 4 87.08 * 0.04 * * * 0.36 0.11 0.04 0.03 * 13.27 100.9 gn 5 86.31 * .* * * * 0.41 0.15 0.01 * * 13.41 100.3 gn 6 86.03 * * * * * 0.46 0.11 0.02 0.11 * 13.91 100.8 gn 12 86.96 * * * 0.13 * 0.5 0.1 0.08 * 0.04 13.12 100.9 sl 7 0.24 65.17 * * * 0.06 0.18 0.08 * 0.56 * 33.81 100.1 sl 8 0.34 66.5 * 0.02 * * 0.08 * 0.06 0.55 * 33.23 100.8 sl 9 0.11 65.06 0.06 * * 0.01 0.15 0.09 0.02 0.58 * 33.26 99.34 sl 11 0.2 65.44 * * * 0.04 0.05 0.07 * 0.54 * 33.49 99.83 g eo lo gi a c ro at ic a geologia croatica 75/1154 4.2.3. electron probe microanalysis (epma) for a more detailed study on the ag and other trace elemental content of the ore, electron probe microanalysis (epma) was performed at twelve points on tetrahedrite, galena, and sphalerite minerals of an ore sample (fig. 8), at the iranian mineral processing research center (imprc) laboratory (table 3). tetrahedrite occurs as a replacement in galena in the first and more in the second stage, and in the early stage of galena mineralization. some anhedral tetrahedrite occurs as an open space filler in the barite crystals. based on these investigations, zinc is concentrated in sphalerite and to some extent in tetrahedrite, while ag, as, sb and cu are concentrated in the tetrahedrite mineral network that formed before galena based on the mineral paragenesis. the amount of silver in the tunnels (mostly in discordant veins) has been reported to reach up to 7030 ppm by the damavand mining company (2013), measured at the ayarjouyan novin laboratory, iran. 5. results 5.1. geochemistry the contents of the major, trace, and rare earth elements according to icp-ms of the duna mine are given in tables 1 and 2. the samples dsa1 and dsa4 represent the discordant/second stage/ younger/irish-type of mineralization, while samples dsa2b, dsa7, and dsa17 represent the concordant/1st stage older/mvt of mineralization. the average grade of the ore for 1st stage/older/mvt and second stage/younger/irish-type of mineralization is 19.5 and 18.1 wt. % pb, 53.5 and 2541 ppm zn, 81.1 and 146.6 ppm ag, 26.1 and 1132.7 ppm as, 140 and 14310 ppm cu, 469.5 and 66.3 ppm mn, 53.8 and 3875 ppm sb, 233 and 9200 ppm sr, respectively. also the content of elements like mo, u, cd, te, and tl is in some cases considerable. while the content of the above-mentioned elements is higher in the ore compared to the dolomitic host rock and igneous rocks, these rocks are more enriched in the following elements in comparison with the ore; fe, mg, co, cr, cs, mn, sn, th, ti, v, and w. the chondrite-normalized ree patterns (boynton, 1984) in all samples of ore, dolomitic host rock, igneous rock, and barite in the duna pb-ba-(ag) mine and the akapol intrusive mass (sajjadinasab et al., 2000; passand mausoumi et al., 2001), indicate enrichment of lree relative to hree, while all samples show a fractionation from la to yb (fig. 9). the hree concentrations of the ore are more depleted than the lrees-mrees. the chondrite-normalized values of the mineralized host rocks are 1.8 to 2.3 ppm for la and less than 0.05 ppm for yb. the same values for the unmineralized host rock are 35 to 40 ppm for la and about 9.8 ppm for yb, while in the igneous rock they figure 6. a) brecciated texture with? mineralized quartz veinlets as open space filling of dolomite limestone and mineralization of anglesite and limonite in the core of the galena and barite from the tunnel/second stage/younger/irish-type; b) the mineralization of the malachite and azurite in barite with boxwork texture from the open pit/1st stage/older/mvt. ang-anglesite; az-azurite; brt-barite; dol-dolomite; gn-galena; mlc-malachite; qz-quartz. symbols from whitney and evans, (2010). figure 7. summary of the paragenetic sequence of the two stage mineralization; 1st stage/older/mvt and second stage/younger/irish-type in the duna mine. g eologia c roatica sadeghi et al.: geological, geochemical and fluid inclusion investigations on the duna pb-ba-(ag) deposit, central alborz, north central iran 155 indicate 30 to 400 ppm for la and 20 to 60 ppm for yb. the total amounts of ree (σree) are very low and fall in the ranges of 2.19−9.69 ppm for ore samples, while the average is 8.7 ppm for barite. on the other hand, the average ree amounts (σree) are about 244.9 ppm for the melaphyre unit (igneous rock), 89.74 ppm for the dolomitic host rock and 225.8 ppm for the akapol intrusive mass. remarkably, the patterns presented in fig. 9 show that the ree values in the ore and barite in the first and second stage of mineralization are neither similar to the samples of igneous rock, dolomitic host rock, nor the akapol intrusive mass. the chondrite-normalized ree patterns of eu and ce (mc lennan, 1989), for ore samples, indicate negative ce (varying from <1 to 2) and strong positive eu (varying from <0.1 to 2.26) anomalies, and were calculated using the following formula; (eu/eu ⃰= eun / [(√smn × √gdn)] & ce/ce⃰ = cen / [(√lan × √prn)], n=normalized). the chondrite-normalized ree patterns of eu and ce for igneous and host rocks, show weak negative ce and weak positive eu. 5.2. fluid inclusion fluid inclusions were studied from barite of concordant and discordant veins in the tunnel and the open pit. the sample dsa2a was taken from the concordant veins and represents the 1st stage/ older/mvt of mineralization, while samples dsa4 and dsa8 were taken from the brecciated area of fault zones and discordant layers which represents the second stage/younger/irish-type of mineralization. barite was selected for the study of the fluid inclusions due to its transparency and presence in the main mineralization stage. a total of 62 fluid inclusions from four doubly polished-thin sections were measured (table 4). 5.2.1. study of fluid inclusions in the 1st stage/ older/mvt petrographic studies of fluid inclusions in the first stage of mineralization in the barite samples distinguished two types of inclusions: liquid-vapour (l-v) and less common mono-phase liquid (fig. 10a, c). the liquid-vapour (l-v) inclusions (fig. 10a) hosted in barite are liquid rich. the liquid/vapour ratio is 70 to 80 in these inclusions. the fluid inclusions are of primary origin but a number of fluid inclusions in micro-cracks cutting with linear arrangement in different directions can indicate the secondary origin or the next generation of the inclusions as a result of stress and joint formation in the study area (fig. 10c). the size of fluid inclusions with elongate and regular polyhedral shapes is 5 to 25 µm in the concordant layers. microthermometric measurements in the 1st stage veins were performed on the primary two-phase (l-v) inclusions (tab. 4). the first melting temperature (tfm) that corresponds to the eutectic temperature is -55 ºc to -45 ºc for all fluid inclusions. this low temperature that is due to the drop in freezing point of pure water depends on the type of salt (nacl, cacl2, and kcl) in the figure 8. electron probe microanalysis (epma) images for tetrahedrite (tt), galena (gn), and sphalerite (sl). table 4. fluid inclusion studies data in barite from both the open pit and a tunnel in the duna mine. n: number of fluid inclusion; tfm: temperature of first melting; tm: temperature of last melting; tm-hh: temperature of melting hydrohalite; th: temperature of homogenization; nm: not measured; dis: discordant veins (mostly second stage/younger/irish-type); con: concordant veins (mostly 1st stage/older/mvt). dsa8 tunnel (dis) dsa4 open pit (dis) dsa2a open pit (con) sample code location baritebaritebaritehost 242117n 10 to 807 to 255 to 25size (µm) l+vl+vl+vinclusion type –55 to –45–55 to –45–55 to –45tfm (ºc) –7.9 to –20.5–4.3 to –23.5–11.5 to –24tm (ºc) –18 to –23.5–25 to –34–25 to –27tfm hh (ºc) 9.05 to 17.123.96 to 13.028.29 to 22.2nacl (wt. %) 2.46 to 6.023.38 to 16.987.82 to 13.21cacl2 (wt. %) 11.78 to 22.297.34 to 22.7618.54 to 23.65nacl+cacl2 (wt. %) 187 to 285113 to 268135 to 165th (ºc) g eo lo gi a c ro at ic a geologia croatica 75/1156 solution and is related to the salt system (shepherd et al., 1985). this suggests that the ore-forming fluids that precipitated the barite and galena were hydrothermal fluids containing nacl and cacl2. the melting point of hydrohalite (tmhh) in the fluid inclusions has a range of -27°c to -25 °c, which indicates the different ratios of nacl/nacl+cacl2 (goldstein & reynolds, 1994). the last ice melting temperature (tmice) of the inclusions ranged from -23.5 ºc to -4.3 ºc (average -17.2 ºc). the relationship between the last ice melting and salinity (wt. % nacl eq.) shows the salinity of the ore-forming fluids (shepherd et al., 1985). all inclusions in the 1st stage of mineralization homogenized between 135 ºc to 165 ºc (average 161.5 ºc). the salinity of fluid inclusions (nacl+cacl2 wt. %), ranged from 18.54−23.65 wt. % nacl equivalent (average 19.92 wt. % nacl equivalent). 5.2.2. study of fluid inclusions in the second stage //younger/ irish-type petrographic studies of fluid inclusions in the discordant/second stage/younger/irish-type of mineralization in the barite samples distinguished three types of inclusions: liquid-vapour (l-v), mono-phase liquid and mono-phase vapour (v) in the dsa4 sample (fig. 10b). the simultaneous absence of liquid-rich and vapour-rich two-phase inclusions indicates the lack of boiling in the area (moncada et al., 2012; hashemian et al., 2018). however, the presence of mono-phase gas can indicate local boiling of the fluid as a result of pressure reduction at the fractures and faults in the second stage/younger/irish-type of mineralization. the fluid inclusions of primary origin are characterized by the large size of the host crystal, and their separation from adjacent inclusions (shepherd et al., 1985) that are interpreted as representing the ore-forming fluids. most of the fluid inclusions are in elongate and regular polyhedral shapes with sizes ranging from 7 to 80 µm. the elongation of some fluid inclusions can be indicative of tectonic stresses in the area (hashemian et al., 2018). fluid inclusions in the barite samples in the discordant layers are larger in size (7−80 µm) of the concordant layers (5−25 µm). the liquid/vapour ratio is 70:80. the inclusion contents homogenized into a liquid phase upon heating, indicate mineralization under hydrothermal conditions with no boiling in the formation of the fluids involved (shepherd et al., 1985). necking down, which is a phenomenon of dividing large, wide, and irregular primary inclusions into a number of smaller and more regular inclusions (shepherd et al., 1985) is seen in some sections (fig. 10d). microthermometric measurements in the second stage/ younger/irish-type of mineralization were performed on the primary two-phase (l-v) inclusions (table 4). the temperature of first melting (tfm) is -55 ºc to -45 ºc for all fluid inclusions. the melting point of hydrohalite (tmhh) in the inclusions has a range figure 9. chondrite-normalized ree patterns (boynton, 1984) for samples from ore, host rock (hr), igneous rock (ir), and barite (brt) in the duna mine and the akapole intrusive mass (ak). ree-pattern irregularities of the ore, as a result of mixing of two mineralizations; 1st stage/older/mvt and second stage/younger/irish-type. figure 10. a) photomicrograph illustrating two-phase liquid and vapour (l+v) fluid inclusion and monophase liquid trapped in barite; b) fluid inclusions of twophase liquid and vapour (l+v) and monophase liquid (l) and vapour (v); c) linear arrangement of fluid inclusions; d) necking down in fluid inclusion hosted in barite in the duna mine. g eologia c roatica sadeghi et al.: geological, geochemical and fluid inclusion investigations on the duna pb-ba-(ag) deposit, central alborz, north central iran 157 of -34 °c to -18 °c. the last ice melting temperature (tmice) of the inclusions ranged from -23.5 ºc to -4.3 ºc (average -15.42 ºc). all inclusions in barite from the second stage/younger/irishtype of mineralization homogenized between 113 ºc to 285 ºc (average 197.63 ºc). based on fig. 11a, most of the fluid inclusions are homogenized in the range of 150−250 ºc (mostly 210 ºc), and a small number are homogenized in the range of 260−280 ºc from the discordant layers. this high homogenization temperature in barite seems to be acceptable due to the lack of leakage and bursting in the inclusions. to ensure the absence of leakage in fluid inclusions, a thermometer test was performed with great care. the argued h2o leakage from originally water rich fluid inclusions, may result in extremely gas-rich fluid inclusions (bakker & jansen, 1990). the salinity of fluid inclusions (nacl+cacl2 wt. %) in two studied sections, ranged from 7.34−22.76 wt. % nacl equivalent (average 18.90 wt. % nacl equivalent) in second stage/younger/ irish-type of mineralization (fig. 11b). according to these salinity values, the duna mine’s ore-forming fluids were high-salinity fluids. 6. discussion 6.1. origin of metals, fluids, and the mineralization type lead mineralization in the alborz zone attributed to the orogenic events that went on the alborz zone after the cretaceous period and accompanied by tectonic events and crustal thickening which led to the migration of lead from the old sources (mesozoic and cenozoic periods) and eventually mineralization in the younger rock units (mirnejad et al., 2015). previous studies in the field of economic geology and ore genesis over the duna mine have suggested diverse origins for the lead mineralization which include: a product of epithermal to mesothermal mineralizing process simultaneous with activity of submarine hydrothermal fluids (holzer & momenzadeh, 1969; samani rad, 1999), a magmatic source for the mineralizing fluids (samani-rad, 1999), permian volcanogenic origin (holzer & momenzadeh, 1969), a mississippi valley-type (mvt) ore deposit (yaghoob poor, 2004), sedex (bazargani-guilani, 1982), and a skarn type, or the tertiary magmatic activity related (hassanzadeh et al., 2002; nekouvaght tak et al., 2009). the present study, according to the following evidence, shows that the mineralization in the duna mine includes two major mineralization phases; 1st stage/older/mvt (mostly concordant layers) overprinted by a second stage/younger/irish-type (mostly discordant layers). comparison of the characteristics of the duna mine with the mvt and irish-type deposits (table 5), shows similarities with these mineralization types such as host rock, form of mineralization, epigenetic nature, alteration types, zn/(zn+pb) ratio, and geological and tectonic settings (robb, 2005; shahabpour, 2010). in terms of some features, such as homogenization temtable 5. comparison of the mineralization characteristics of the duna mine with irish-type and mvt deposits from robb (2005), shahabpour (2010) and bodnar et al. (2014). mvtirish-typeduna minespecification dolomite and sanddolomitic limestonedolomitic limestonehost rock 75 ºc – 200 ºc150–240 ºc106–285 ºcfluid inclusion (temperature) 10−30 %10−23 % (<15 %)7.34−23.76 %nacl wt.% eq. strataboundstratabound and stratiformstrataboundform of reserve pb, zn, cd, gepb,zn, ag, cu, fepb,zn, ag, ba,fe, cuore mineralogy galena,sphalerite, barite, fluorite galena, sphalerite, barite, chalcopyrite, tetrahedrite galena, sphalerite, barite, chalcopyrite, tetrahedrite ore and gangue type epigeneticepigenetic and syngeneticepigeneticsyngenetic and epigenetic fracture infilling, replacement disseminated, bedded, open space infilling disseminated, bedded, fracture infilling, replacement geologic relationship and host rock usually nonexistence, mafic and alkali magma basaltic magma activitybasaltic volcanic and subvolconic rockmagmatism dolomitic and siliceousdolomitic and siliceousdolomitic and siliceousalteration 0.6 – 0.80.6 – 0.80.002 – 0.1zn/zn+pb marginal basin, rift, carbanate platformshallow marginal seas, rift basins shallow marginal seas, rift basins palaeozoic geological and tectonic setting mostly in palaeozoicmostly in palaeozoicpalaeozoictiming of mineralization figure 11. histograms showing frequency of distribution of homogenization temperature (th) and salinity (wt % nacl eq.) for fluid inclusions of barite from concordant and discordant layers in the duna mine. g eo lo gi a c ro at ic a geologia croatica 75/1158 perature of fluid inclusions, presence of high ag and other trace elements in the ore samples, mineralogy and gangue, in most discordant layers the duna pb-ba-(ag) mine is comparable to the irish-type deposit. fluorite is usually present in mvt deposits while it is rarely reported in irish-type deposits (gize & barnes, 1987). the concentration of some trace elements such as cu, as, and sb in the duna mine is similar to the irish-type and magmatic pb-zn deposits (leach et al., 2005). the high amount of mg (3.6 wt. %) in the host rock of the duna pb-ba-(ag) mine indicates its high dolomite content formed locally, while the change in its colour from gray to brown was due to its high iron content (8.8 wt. %). the evidence of dolomitization is the high mg content and the low ca/mg ratio (plumlee et al., 1994) as well as the reaction between the mineralized fluid and carbonate host rock. in the duna mine, lead has a higher enrichment than zinc, and zn/(zn+pb) ratio is lower than 0.1, which is comparable to mvt and irish-type deposits. according to table 1, it seems that the average amount of lead (18.5 %) in both discordant and concordant veins is approximately equal. after lead, silver is the second economically important element in the duna mine. figure 12. homogenization temperature-salinity plot for fluid inclusions from ore samples of concordant veins/ 1st stage/older/mvt (dsa2a), and second stage/ younger/irish-type (dsa4 and dsa8) in the duna mine. figure 13. a homogenization temperature-salinity diagram (bean, 1983) for ore-bearing fluids from open pit/1st stage/older/mvt (dsa2a), and discordant veins/ second stage/younger/irish-type (dsa4 and dsa8) in the duna mine. g eologia c roatica sadeghi et al.: geological, geochemical and fluid inclusion investigations on the duna pb-ba-(ag) deposit, central alborz, north central iran 159 the silver content of the pb-zn deposits in relation to magmatic deposits is usually more than 1000 ppm and up to 5000 ppm while less than 500 ppm in sedimentary deposits (qian, 1987; nejadhadad et al., 2015). silver content in the duna mine ranges from 18.9−264.3 ppm (average 120.4 ppm) in the open pit (mostly concordant layers; 1st stage/older/mvt) while it ranges from 9 to 7030 ppm (average 1553 ppm) in the tunnels (mostly discordant layers; second stage/younger/irish-type), according to a 45 mineral chemistry analysis by the damavand mining company (2013). this indicates a change in the mineralization conditions or differences in the type of ore-forming fluids. paragenesis of high temperature minerals such as pyrite and chalcopyrite and co-precipitation of sphalerite and chalcopyrite (fig. 5a) indicates high temperature of the mineralizing fluids (bortnikov et al., 1991). the high content of ag, cu, as, and sb in the duna mine which is associated with the second stage/younger/irish-type of mineralization is also very similar to the pb-zn deposits associated with magmatic activities (leach et al., 2005). the chondrite-normalized ree patterns of the mineralized host rock show a negative ce anomaly and positive eu anomaly. the positive anomaly of eu and the weak anomaly of ce correspond to the pattern of a magmatic fluid (kato, 1999). the mineralized host rock indicates differences in σree, negative ce, and positive eu compared to the unmineralized host rock, the igneous rocks, and the akapol intrusive mass. this may be indicative of a difference in the ree source in the mineralized rocks and unmineralized rocks. the eu positive anomaly in sample dsa17 from the discordant/second stage/younger/irish-type is different and higher than the other samples. the ree patterns of the mineralized host rock show an irregularity and heterogeneity that can result from the mixing of magmatic fluids with basin and atmospheric waters (kato, 1999). the significant salinity variations, are most likely to be controlled by different origins and fluid mixing. salinity of fluid inclusions of concordant/1st stage/older/ mvt (sample dsa2b) with the range of 18.54 to 23.65 (average 19.92) wt. % nacl equivalent and a homogenization temperature of 135-165 °c in the duna pbba-(ag) mine revealed that the ore-forming fluids were of lowtemperature, high-salinity h2o-nacl system fluids. the results of fluid inclusion analyses in discordant/second stage/younger/ irish-type (samples dsa4 and dsa8) demonstrate a wide salinity range of 7.34 to 22.76 wt. % nacl equivalent and a homogenization temperature of 105-285 °c. these fluid inclusions can be subdivided into three groups: a low-salinity with average 7.34 wt. % nacl equivalent, an intermediate-salinity with 11.78 to 17.1 (average 16.04) wt. % nacl equivalent, and a high-salinity with 20.55 to 23.65 (average 21.76) wt. % nacl equivalent. this variety of salinity values can be due to the different origins of fluids or combinations of several fluid types through factors such as isothermal mixing, heating depressurization, and surface fluid dilution. the homogenization temperature of fluid inclusion in mvt deposits ranges from 75 to 175 °c, while salinities are about 20 ± 5 wt. % nacl equivalent (bodnar et al., 2014). it seems that fluid inclusions of concordant veins at temperatures about 155−165 °c were formed in the 1st stage/older/mvt of mineralization, while fluid inclusions of discordant mineralized veins, were mostly formed in the second stage/younger/irish-type of mineralization, entrapped in temperatures between 113−285 °c. this may indicate different formation conditions of the discordant mineralized veins compared to the concordant mineralized veins. there is no correlation between homogenization temperature and salinity (fig. 12), but high-salinity and high homogenization temperature values of inclusions suggests that some magmatic and meteoric fluids were mixed (arribas et al., 1995). rapid precipitation of sulfides, may have been driven by mixing between brines and higher temperature metal-bearing fluids derived from a basement-equilibrated fluid reservoir (wilkinson & eyre, 2005) and/or at least spatially with igneous intrusions and saline springs (banks et al., 2002). the homogenization temperature-salinity diagram for ore-bearing fluids (beane, 1983), indicates the involvement of basin brine fluids in concordant veins (dsa2a), and magmatic-meteoric fluids in discordant veins (dsa4 and dsa8) in the duna mine (fig. 13). a compilation of th-salinity information from different deposit types (roedder, 1984), indicates that ore-forming fluids in the duna mine (fig. 14), figure 14. homogenization temperature-salinity plot for fluid inclusions (roedder, 1984) from an ore sample of the open pit and massive barite of tunnel for mvt (dsa2a), and irish-type (dsa4 and dsa8) of mineralization in the duna mine. g eo lo gi a c ro at ic a geologia croatica 75/1160 have a proximity to an mvt deposit (mostly concordant/dsa2a), and irish-type ore deposits (mostly discordant/dsa4 and dsa8). variation in the last ice melting temperature of the fluid inclusions can be the result of variation in the salinity content of the multiple fluid sources and fluid mixing. the various fluid evolution processes on the th-salinity bivariate plot (wilkinson, 2001), show that the surface fluid dilution in 1st stage /older/mvt, and surface fluid dilution, isothermal mixing, and ultimately cooling processes of the ore-forming fluids occurred in second stage/younger/irish-type of mineralization in the duna mine (fig. 15). the process of cooling and dilution could be the main reason for deposition. the study of the pb-zn mining areas in ireland (silvermine, tynagh, lisheen, navan and keel deposits), shows that a large flow of fluids, at a depth of about 6 km in the northern part of this mining area (navan، keel and tynagh deposits), supplies a fluid temperature of about 200 ºc, while in the southern region (silvermine and lisheen deposits), the fluid temperature is about 300 ºc, which is the result of the influence of a mafic intrusive mass (wilkinson & hitzman, 2015). the microthermometry of fluid inclusions in the barite host from the silvermine deposit shows that the salinities range from 8 to 28 equivalent wt. % nacl, while the homogenization temperatures range from 50 to 260 °c (samson and russell, 1987). therefore, according to the study of the fluid inclusions, the second stage of the duna mine can be comparable to the silvermine and lisheen deposits of the irish midlands basin. according to the isotopic ratios, 206pb/204pb, 207pb/204pb, 208pb/204pb, 238u/204pb, the mineralization age of the duna mine constrained to ~50±6 ma (mirnejad et al., 2015), which is nearly synchronous with the intrusion of the akapol granitoid which is equal to 54±4 to 56±3 ma measured by ar40-ar39 and u-pb (axen et al., 2001b) and represents the second stage/ younger/irish-type of mineralization. the most important role of the akapol intrusive mass has been as a heat source for the oreforming fluids. therefore, the akapol granitoid intrusive mass has played an influential role in the second stage/younger/irishtype of mineralization in the duna mine and can be compared to the mafic intrusive bodies in the silvermine and lisheen deposits in ireland. 6.2. genetic model the discordant mineralized samples in the permian dolomitic carbonate host rock of the duna pb-ba-(ag) mine are comparable to an epigenetic mineralization. samples collected from the concordant layers which indicate simple mineralogy and low ag, sb, and cu content are consistent with mvt deposits (dill et al., 2011). the study of fluid inclusions in the concordant/1st stage shows that the salinity and th (18.5423.65 wt % nacl equivalent, 135 -165 °c) is compatible with the salinity and th range of mvt ore fluids (10–30 wt % nacl equivalent, 75–200 °c). these high-salinity fluids could have been derived from the evaporation of seawater and the precipitated halite (banks et al., 2002). since barite accompanies galena in the duna mine, the high salinity and metal rich fluids could have influenced this type of occurrence in the 1st stage/older/mvt of mineralization. in the northern alborz, including the study area, three intense deformation phases occurred after the jurassic, especially during the late cretaceous, eocene-oligocene, and pliocene (axen et al., 2001b; allen et al., 2003; guest et al., 2006; hakimi asiabar & bagherian, 2018). the early cimmerian orogenic movements in the alborz mountain range caused an angular unconformity between the jurassic and triassic rock units. this could be a major reason for the evolving stratabound and stratiform permian-hosted 1st stage/older/mvt mineralization in the duna mine. a schematic overview of the genetic model of the duna pbba-(ag) mine (fig. 16) with respect to the geological and tectonic sections of the northern alborz (fig. 16a), shows that the late cretaceous-tertiary tectonic conditions have caused uplift, folding, first generations of faults (w-e direction), and inversion tectonics style of deformation along previous normal faults which in turn generated numerous north and south verging thrust faults (axen et al., 2001b; allen et al., 2003; fursich et al., 2005; figure 15. a schematic diagram showing typical trends in homogenization temperature-salinity space due to various fluid evolution processes (wilkinson, 2001) and the position of ore-bearing fluids for mvt (dsa2a/open pit), and irish-type (dsa4/open pit and dsa8/tunnel) of mineralization in the duna mine. g eologia c roatica sadeghi et al.: geological, geochemical and fluid inclusion investigations on the duna pb-ba-(ag) deposit, central alborz, north central iran 161 guest et al., 2006). in the structural units within the study area (fig. 16b, c) these faults are the result of the formation of the duna anticline due to the laramide orogeny. in the eocene, another extensional event occurred with subsidence and remarkable eruptions in the alborz range, with some magma intrusions, which continued with a compression event of the late eoceneoligocene. the pyrenean orogeny, in addition to generating secondgeneration faults (wsw-ene directions), caused the intrusion of large masses in the northern alborz, such as the akapol intrusive mass at a distance of 4 km south of the duna mine. the discordant mineralization in the duna mine is more compatible with the high content of ag, sb, cu, as and sr in the irish-type deposits than in the mvt deposits. the ore mineralization in the duna mine is enriched in pb compared to zn. the salinity and th of the duna mine ore fluids (7.34–22.76 wt % nacl equivalent, 113-285 °c) are more comparable to the salinity and th of ore fluids in the silvermine deposit of the irish midlands basin (8–28 wt. % nacl equivalent, 50-260 °c/or 300 °c) in the host rock barite (samson &russell, 1987). in general, fluid inclusion studies on the second stage show that two fluids with different th but similar high salinity were mixed during mineralization. one of the fluids that had high salinity and high th, was probably metal-rich and has been affected by the intrusive mass of akapol. the tectonic movements and activities related to the akapol intrusive mass in the late paleocene to early eocene of the region (fig. 16d, e), resulted in faulting or dilatation along the main structural patterns as well as an increase in temperature and a pressure drop in the crust. this was often associated with deformation in the tectonic motions of this period, fluid motion, and occurrence of hydrothermal breccia (hakimi asiabar & bagherian, 2018). therefore, the ore-bearing elements have been washed out from their original location and deposited as veins and veinlets along strike-slip faults and in open spaces. this happened in the core of the anticline under appropriate physicochemical conditions in the first and second generation of faults as the feeding zones of the fluid flow. thus the second stage/younger/irish-type was formed as a result of the cenozoic orogenic phases with the intrusion of plutonic bodies such as the akapol intrusive mass (mostly discordant layers) which impacts on the 1st stage/older/mvt ore deposit (mostly concordant layers). figure 16. schematic model of the genesis of the duna pb-ba-(ag) mine. a) the tectonostratigraphic chart (modified after hakimi asiabar and bagheryian, 2018) of the northern alborz range; b, c, d, e) schematic model for the formation processes of faults and folding, akapol intrusive; f ) analog deformation model (mc clay and bonora, 2000). g eo lo gi a c ro at ic a geologia croatica 75/1162 7. conclusion the study of geology, mineralogy, geochemistry and fluid inclusion in the duna pb-ba-(ag) mine indicates the occurrence of two stages of mineralization. the epigenetic duna mineralization occurs at the core of an anticline, controlled by faults, and chemically affected by bituminous layers, dolomitic horizons, and impermeable volcanic rocks of the permian. microscopic and field investigations of concordant and discordant ore samples indicate that they consist mainly of galena and minerals such as sphalerite, tetrahedrite, pyrite, and chalcopyrite. barite, dolomite, calcite, and quartz are the gangue minerals. supergene minerals include feoxides, covellite, cerussite, anglesite, malachite and azurite. texture evidence shows that the ore bodies mostly filled structural open-spaces of the dolomitic host rock. mineralogy, texture, and paragenesis of the concordant mineralization are more comparable to mvt deposits, while the evidence such as paragenesis of minerals formed at high temperature e.g. pyrite and chalcopyrite as well as co-precipitation of sphalerite and chalcopyrite in discordant mineralization is mostly comparable to irish-type deposits. geochemical analysis of discordant mineralization layers shows enrichment of ag (146.6 ppm), as (1132.7 ppm), cu (14310 ppm), sb (3875 ppm), and sr (9200 ppm) compared to mineralized concordant layers which is comparable to irish-type deposits. salinity of fluid inclusions of concordant layers has a range of 18.54 to 23.65 wt. % nacl equivalent and a homogenization temperature of 135-165 °c which is comparable to mvt deposits, while the discordant layers with a wide salinity range from 7.34 to 22.76 wt. % nacl equivalent and the high homogenization temperature of 105 to 285 °c are comparable to irish-type deposits. the aforementioned evidence together with the tectonic setting and the structural units, positive anomalies of eu/eu⃰, noncompliance of ree pattern of mineralized samples with the surrounding rocks, and simultaneous formation of the duna mine (50±6 ma/ mirnejad et al., 2015) and the akapol granitoidic intrusive body (54±4 to 56±3 ma/ axen et al., 2001b) suggest the occurrence of two stage of mineralization in duna namely the concordant/1st stage/older/mvt, and the discordant/second stage/younger/irish-type. the early cimmerian orogenic movements in the alborz mountain range created an angular unconformity between the jurassic and triassic rock units, and it could have been a good reason for the evolving stratabound and stratiform permian-hosted 1st stage/older/mvt deposits. the occurrence of the second stage/younger/irish-type deposit is the result of the laramide orogenic movements. the mixing of two mineralizations in the second stage (overprint) as a result of the effect of magmatic fluid has made it impossible to determine the type of ore deposit in the duna mine. the second stage/younger/irishtype deposit is comparable to the silvermine and lisheen deposits in the pb-zn mining area in ireland. acknowledgment this project was supported by the damavand mining company. we would like to thank mr. amin akrami and mr. arash mirshahi who were the chief executives of the damavand mining project and supported us with sharing their information. we would also like to thank two anonymous reviewers for their very constructive suggestions and comments. references aghanabati, a. (2004): geology of iran.– geological survey of iran publication. tehran, 733 p. alavi, m. (1991): tectonic map of the middle east (scale 1:5.000.000).– geological survey and mineral exploration of iran, tehran. allen, m., ghassemi, m.r., shahrabi, m. & qorashi, m. (2003): accommodation of late cenozoic oblique shortening in the alborz range, northern iran.– j. structural. geol., 25, 659–672. doi.org/10.1016.s0191-8141 (02) 00064-0 annells, r.n. (1975): explanatory text of the qazvin and rasht quadrangles map.– geological survey of iran, e3 and e4, 94 p. arribas, a.j.r., cunningham, c.g., rytuba, j.j., rye, r.o., kelly, c., podwysocki, m.h., mckee, e. h. & tosdal, r. m. (1995): geology, geochronology, fluid inclusions and isotope geochemistry of the rodalquilar au alunite deposits, spain.– economic geology, 90, 795–822. axen, g.j., stockli, d.f., lam, p., guest, b. & hassanzadeh, j. (2001b): implications of preliminary (u-th/he cooling ages from the central alborz mountains, iran.– geological society of america, abstracts with programs., 33, 257 p. baharfiruzi, k.h. & shafeii, a.r. (2005): geological map of javaherdeh sheet.– geological survey of iran 1:100.000. bakker, r.j. & jansen, b.h. (1990): preferential water leakage from fluid inclusions by means of mobile dislocation.– nature, 345, 58–60. doi: 10.1038/345058a0 banks, d.a., boyce, a.j. & samson, i.m. (2002): constraints on the origins of fluids forming irish zn-pb-ba deposits: evidence from the composition of fluid inclusions.– economic geology, 97, 471–480. doi: 10.2113/gsecongeo.97.3.471 bazargani-gilani, k. (1982): die mittelpermischen scichtgebundenen blei-zinkschwerspatlargestattendes kalawanga distriktes. zentral alborz, iran (mit besonderer berucksichtigung des duna-grubenfelds).– diss univ. heidelberg. bean, r.e. (1983): the magmatic-meteoric transition.– geothermal resources council, special report, 13, 245–253. berberian, m. & king, g.c.p. (1981): towards a paleogeography and tectonic evolution of iran.– can j earth sci, 8, 210–265. doi: 10.1139/e81-019 bodnar, r.j., lecumberri-sanchez, p., moncada, d. & steele-maclnnis, s. (2014): fluid inclusions in hydrothermal ore deposits.– in: holland, h.d. and turekian, k.k. (eds.): treatise on geochemistry, vol 133. oxford, elsevier, 119–142. doi: 10.1016/b978-0-08-095975-7.01105-0 boynton, w.v. (1984): cosmochemistry of the rare earth elements; meteorite studies.– in: henderson, p., (ed.): rare earth element geochemistry. amsterdam and new york, elsevier science, 63–114. doi.org/10.1016/b978-0-444-421487.50008-3 bortnikov, n.s., genkin, a.d., dobrovol’skaya, m.g., muravitskaya, g.n. & filimonva, a.a. (1991): the nature of chalcopyrite inclusions in sphalerite: exsolution, coprecipitation, or “disease”?– economic geology, 86/5, 1070–1082. doi: 10.2113/gsecongeo.86.5.1070 davidheiser-kroll, b.j. (2014): understanding the fluid pathways that control the navan ore body.– ph. d. thesis. university of glasgow, scotland. dill, h.g., weiss, w, botz, r. & dohrmann, r. (2011): paleontological, mineralogical and chemical studies of syn genetic and epigenetic pb-zn-ba-p mineralization at the stratotype of the k/p boundary (el kef area, tunisia).– int j earth sci, 100, 805-846. doi: 10.1007/s00531-010-0517-2 fursich, f.t., wilmsen, m., seyed-emami, k., cecca, f. & majidifard, m. r. (2005): the upper shemshak formation (toarcian-aalenian) of the eastern alborz (iran): biota and palaeo environments during a transgressive-regressive cycles.– facies, 51, 379–398. doi: 10.1007/s10347-005-0051-z ghorbani, m., (2013): the economic geology of iran mineral deposits and natural resources.– springer, 569 p. doi:10.1007/978-94-007-5625-0 gize, a.p. & barnes, h.l. (1987): the organic geochemistry of two mississippi valley-type lead-zinc deposits.economic geology, 82/2, 457–470. doi: 10.2113/ gsecongeo.82.2.457 goodfellow, w. & lydon, j. (2007): sedex deposits.– geological survey of canada, 16 p. goldstein, r.h. & reynolds, t.j. (1994): systematics of fluid inclusion in diagnostic minerals: sepm short course 31.– society for sedimentary geology, tulsa ok, pp 199. golonka, j. (2004): plate tectonic evolution of the southern margin of eurasia in the mesozoic and cenozoic.– tectonophysics., 381, 235–273. doi.org/10.1016/j.tecto.2002.06.004 guest, b., axen, g.j., lam, p.s. & hassanzadeh, j. (2006): late cenozoic shortening in the west-central alborz mountain, northern iran, by combined conjugate strike slip and thin-skinned deformation.– geosphere., 2/1, 35–52. doi. org/10.1130/ges00019.1 hakimi asiabar, s. (2019): structural deformations of the duna mine area.journal of earth sciences.– geological survey & mineral explorations of iran, 28, 235–246. hakimi asiabar, s. & bagheriyan, s. (2018): exhumation of the deylaman fault trend and its effects on the deformation style of the western alborz belt in iran.– int j earth sci (geol rundsch), 1–13. doi: 10.1007/s00531-017-1507-4 hashemian, e., jamali, h. & ahmadian, j. (2018): mineralogy, fluid inclusion and geochemistry of tappeh-khargosh cu-au deposit (sw of ardestan), iran.– journal of economic geology, 10/2, 299–324. hassanzadeh, j., ghazi, a.m., axen, g., guest, b., stocklin, d. & tucker, p. (2002): oligocene mafic-alkaline magmatism in north and northwest of iran: g eologia c roatica sadeghi et al.: geological, geochemical and fluid inclusion investigations on the duna pb-ba-(ag) deposit, central alborz, north central iran 163 evidence for the separation of the alborz from the urumieh-dokhtar magmatic arc (abstract).– geological society of america, 34, 331 p. hitzman, m.w. & beaty, d.w. (1997): the irish zn-pb-(ba) orefield.– in: sangster, d.f. (ed.): carbonate-hosted lead-zinc deposits. society of economic geologists, special publication, 4, 112–143. holzer, h.f. & momenzadeh, m. (1969): note on the geology of elika and duna lead mines, central alborz.– g.s.iran, 14 p. horton, b.k., hassanzadeh, j., stockli, d. f., axen, g. j., gillis, r. j., guest, b., amini, a.h., fakhari, m., zamanzadeh, s.m. & grove, m. (2008): detrital zircon provenance of neoproterozoic to cenozoic deposits in iran: implications for chronosrtatigraphy and collisional tectonics.– tectonophysics, 451/1-4, 97–122. doi: 10.1016/j.tecto.2007. 11 .063 kato, y. (1999): rare earth elements as an indicator to origins of skarn deposit: example of the kamioka zn-pb and yoshiwara-sonnatak cu (-fe) deposits in japan.– resourse geology, 49/4, 183–198. doi: 10.1111/j.1751-3928.1999.tb00045.x leach, d.l., & sangster, d.f. (1993): mississippi valley-type lead-zinc deposits. in: kirkham, r.v., sinclair w.d., thorpe r.i. & duke, j.m. (eds.): mineral deposit modeling. geological association of canada special paper, 40, 289–314. leach, d.l., sangster, d.f., kelley, k.d., large, r.r., graven, g., allen, c.r., gutzmer, j. & walters, s. (2005): sediment-hosted pb-zn deposits: a global perspective.– in: hedenquist, j.w. et al. (eds.): one hundredth anniversary volume. doi: 105382.av100.18 mc clay, k. & bonora, m. (2000): analog models of restraining stopovers in strikeslip fault systems.– aapg bulletin., 85/2, 233–260. mc lennan, s.m. (1989): rare earth elements in sedimentary rocks: influence of provenance and sedimentary processes.– reviews in mineralogy, 21, 169–200. mirnejad, h., simonetti. a. & molasalehi, f. (2015): origin and formational history of some pb-zn deposits from alborz and central iran: pb isotope constraints.– int. geol. rev., 57, 463–471. doi:10.1080/00206814.2015.1013510 modaresnia, m., khosrotehrani, k., momeni, i. & babazadeh, s.a. (2012): upper cretaceous planktonic foraminiferal biostratigraphy of east dorfak area (guilan – north of iran).– life science journal, 9/1, 242–253. moncada, d., mutchler, s., niebto, a., reynolds, t.j., rimstidt, j.d. & bodnar, r.j. (2012): mineral textures and fluid inclusion petrography of the epithermal ag-au deposits at guanajuato, mexico: application to exploration.– journal of geochemical exploration, 114/12, 20–35. doi: 10.1016/j.gexplo.2011.12.001 nejadhadad, m., taghipour, b., zarasvandi, a. & karimzadeh, s.a. (2015): geological, geochemical and fluid inclusion evidences for the origin of the ravanj pb-ba-ag deposit, north of delijan city, markazi province, iran.– turkish j earth sci., 25, 179–200. doi:10.3906/yer-1501-26 nekouvaght tak, m., bazargani-guilani. k. & framarzi, m. (2009): geology and geochemistry of the lead-zinc carbonated hosted mvt mineralization in the north semnan, central alborz., iran.– in: proccedings of 10th biennial sga meeting townsville, economic geology research unit, james cook university, 499–501. paradis, s., hannigan, p. & dewing, k. (2007): mississippi valley-type leadzinc deposits.– in: goodfellow, w.d. (ed.): mineral deposits of canada: a synthesis of major deposit-types, district metallogeny, the evolution of geological provinces, and exploration methods. geological association of canada, mineral deposits division, special publication, 5, 185–203. pasand mausoumi, j., ganji, a., ansari, m. & modarresnia, m. (2001): geochemical study of trace elements and ree in pb-zn ore deposits, kelardasht area (central area).– j environment. geol., 9/6, 58–63. plumlee, c.s., leach, d.i., hofstra, a. h., landis, g. p., rowan, e. l. & viets, j. c. (1994): chemical reaction path modeling of ore deposition in mississippi vally-type pb-zn deposits of the ozark region, u.s. midcontinent.– econ geol, 90/5, 1346–1349. doi.org/10.2113/gsecongeo.90.5.1346 qian, z.h. (1987): trace elements in galena and sphalerite and their geochemical significant in distinguishing the genetic types of pb-zn deposits.– geochemistry, 26, 177–190. doi.org/10.1007/bf02872218 robb, l.j. (2005): introduction to ore-forming procecces.– blackewll publishing australia, 373 p. roedder, e. (1984): fluid inclusions.– reviews in mineralogy, 12, 644. sajjadi nasab, m., vosoghi abedini, m., emami, m. & ghorbani, m. (2000): akapol intrusive mass lithogenesis, kelardasht area, central alborz, iran. -91/23, 215–229. samani rad, s. (1999): geology, mineralogy and genesis of duna pb deposit from central alborz.– m. sc. thesis, islamic azad university, north tehran branch, iran. samson, l. m. & russell, m.j. (1987): genesis of the silvermines zinc-lead-barite deposit, irland; fluid inclusion and stable isotope evidence.– economic geology., 82/2, 371–394. doi: 10.2113/gsecongeo.82.2.371 shahabpour, j. (2010): feedback concept in the ore forming systems.– resourse geol., 60,109–115. doi: 10.1111/j.1751-3928.2010.00118.x shepherd, t.j., rankin, a.h. & alderton, d.h.m. (1985): a practical guide to fluid inclusion studies.– blackie, the university of california, 239 p. steele-macinnis, m., bodnar, r.j. & naden, j. (2011): numerical model to determine the composition of h2o-nacl-cacl2 fluid inclusions based on microthermometric and microanalytical data.– geochimica et cosmochimica acta, 75/1, 21–40. doi:10.1016/j.gca.2010.10.002 whitney, d.l. & evans, b.w. (2010): abbreviations for names of rock-forming minerals.– american mineralogist.., 95, 185–187. doi: 10.2138/am.2010.3371 wilkinson, j.j. & eyre, s.l. (2005): ore-forming processes in irish-type carbonate-hosted zn-pb deposits: evidence from mineralogy, chemistry, and isotopic composition of sulphides at the lisheen mine.– economic geology, 100, 63–86. wilkinson, j.j. (2001): fluid inclusion in hydrothermal ore deposits.– lithos., 55, 229–272. doi: 10.1016/s0024-4937(00)00047-5 wilkinson, j.j. & hitzman, m.w. (2015): the irish zn-pb orefield: the view from 2014.– in: current perspectives in zinc deposits. irish association for economic geology, geological survey of ireland., 59–69. yaghoobpour, m. (2004): investigation of geochemical, isotopic and fluid inclusion related to the source pb-zn ore deposit in duna.– m. sc, tehran-shomal university. zanchi, a., zanchetta, s., garzanti, e., balini, m., berra, f., mattei, m. & muttoni, g. (2009): the cimmerian evolution of the nakhlak-anarak area, central iran and its bearing for the reconstruction of the history of the eurasian margin.– in: brunet, m. f., wilmsen, m., granath, j.w. (eds.): south caspian to central iran basins. geological society, london, special publications, 312, 261–286. doi:10.1144/sp312.1 zartman, r.e. & doe, b.r. (1981): plombotectonics, the model.– tectonophysics, 75/1–2, 135–162. doi:10.1016/0040-1951(81)90213-4 1. introduction the intra-pannonian inselbergs in northwestern croatia (mts. medvednica, samoborska gora, kalnik, and ivanščica) consist of palaeozoic and mesozoic dinaridic and alpine tectonostratigraphic/-metamorphic units (e.g. pamić & tomljenović, 1998; tari & pamić, 1998; pamić, 2002). the ancient neotethyan oceanic lithosphere that predominantly outcrops in these mountains belongs to the westernmost part of the western vardar ophiolitic unit (sensu schmid et al., 2008, 2020; fig. 1a), or more specifically, the southwest part of the zagorje-mid-transdanubian zone (zmtdz; sensu pamić & tomljenović, 1998; fig. 1b). it is preserved in metre-to-kilometre-scale fragments archived within the ophiolitic mélange (figs. 1b-d). the largest manifestations of triassic-jurassic oceanic lithosphere, preserved as coherent thrust sheets, are found on the northern slopes of mt. medvednica (figs. 1b-d). research on the tectono-sedimentary ophiolitic mélange of the same mountain and the fragments of oceanic crust archived therein, conducted over the past three decades, has identified all components of a typical ophiolitic sequence (halamić, 1998; halamić et al., 1998, 1999; lugović et al., 2007; slovenec & lugović, 2008, 2009; slovenec et al., 2010; slovenec & šegvić, 2023). primarily, these are effusive branches of triassic and jurassic basaltic alkali and tholeiitic lavas with various geochemical affinities (wpab, e-, t-, n-morb, iat, barb, bon), formed in convergent and divergent geotectonic settings. however, the research presented here shows that, in middle triassic basaltic pyroclastic rocks from the mt. medvednica ophiolitic mélange (nw croatia): petrology, geochemistry and tectono-magmatic setting damir slovenec1,*, josip halamić1 and branimir šegvić2 1 croatian geological survey, department of geology, sachsova 2, 10000 zagreb, croatia; (*corresponding author: damir.slovenec@hgi-cgs.hr) 2 texas tech university, department of geosciences, 1200 memorial circle, lubbock tx 79409, u.s.a. doi: 10.4154/gc.2024.06 abstract hectometric blocks of middle triassic mafic pyroclastic rocks, represented by volcanic agglomerates/breccias and lapilli tuffs, form part of the ophiolitic mélange of mt. medvednica, situated in the southwestern segment of the zagorje-mid-transdanubian zone. these rocks share petrochemical characteristics with pyroclastic derivatives of alkali, within-plate basaltic lavas of mts. medvednica, samoborska gora, and kalnik, indicating the occurrence of explosive events preceding the dominant effusive submarine volcanism during the middle triassic (illyrian-fassanian?) stages. the formation of these pre-ophiolitic pyroclastics is associated with an intracontinental rift setting and reflects melts derived from an oib-type enriched mantle plume source. these pyroclastics represent uncontaminated melts that erupted through a highly thinned continental crust. in geodynamic terms, the formation of pyroclastites occurred during the late anisian-early ladinian along the continental margin of palaeotethys through the proto back-arc rifting of continental lithosphere (adria plate), leading to the formation of the maliak/balkan neotethys rift, in the emerging northwestern segment of neotethys. the investigated pyroclastic rocks of mt. medvednica document the extension in an evolved intracontinental rift basin, which immediately preceded the generation of the initial neotethyan oceanic lithosphere during the upper triassic. addition to effusive volcanism, exclusively represented by pillow and massive basalts, pyroclastic rocks also found (figs. 1e, f), though they are rare. these rocks indicate the explosive character of volcanism generated during the middle triassic. this study provides the initial mineralogical, petrological, and geochemical insights into middle triassic pyroclastites from the mélange of mt. medvednica. it offers evidence of a shared petrogenetic and tectonomagmatic evolution of ophiolitic pyroclastic rocks formed during the middle triassic period in the northwestern part of neotethys. 2. geological outlines mt. medvednica is located at the junction of the south-eastern alps, the dinarides and the tisza mega-unit (fig. 1a) and forms part of the southwestern segment of the zagorje-midtransdanubian zone (zmtdz) (pamić & tomljenović, 1998; fig. 1b). the zmtdz is bounded by the periadriaticbalaton lineament to the north and the zagreb-zemplin lineament to the south. it is characterized by mixed alpinedinaridic lithologies. the ophiolitic mélange of the sw segment of the zmtdz crops out at multiple locations in nw croatia’s mountains. these mélange locations collectively make up what is known as the kalnik unit (ku) (haas et al., 2000; fig. 1b). the age of accretion for the ku, which predominantly contains frag mented remnants and allochthonous blocks of the neotethyan oceanic lithosphere, is estimated to range from the callovian to the late valanginian (slovenec & lugović, 2009). different blocks/fragments of triassic and jurassic 2024 | 77/2 | 57–68 | 8 figs. | 3 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society article history: manuscript recieved: december 22, 2023 revised manuscript accepted: march 18, 2024 available online: may 14, 2024 keywords: petrology, geochemistry, basaltic pyroclastic rocks, ophiolitic mélange, middle triassic, zagorje-mid-transdanubian zone, mt. medvednica, croatia mailto:damir.slovenec@hgi-cgs.hr g eo lo gi a c ro at ic a 58 geologia croatica 77/2 igneous and sedimentary rocks are largely incorporated within the mélange matrix through tectonic processes, making it challenging to discern their original geological context of formation (halamić, 1998; slovenec & pamić, 2002). the fragmented rem nants of the ophiolitic sequence of oceanic crust on mt. medvednica actually form a distinct connection between the vardar-dinaridic ophiolites situated to the southwest and the meliata-maliak ophiolites to the northeast (slovenec & lugović, 2009). mt. medvednica is composed of palaeozoic, mesozoicpalaeogene, and neogene-quaternary formations (slovenec & pamić, 2002; belak et al., 2022). in the structural succession, the lowest tectonostratigraphic unit is the metamorphic medvednica unit (haas et al., 2000; fig. 1b). this unit consists of greenschist facies paraand orthometamorphic lower aptian rocks the protoliths of which likely covered the siluarian to ladinian period (šikić et al., 1978, 1979; basch, 1981, 1983; belak et al., 1995, 2022), but also of an epidote-bearing albite granite of middle triassic age (balen et al., 2022). the medvednica unit was thrust over a late jurassic ophiolitic mélange and lower cretaceous turbidite deposited in peripheral foreland piggyback basins, i.e. the kalnik unit (figs. 1c, d). these units were overlain by upper cretaceous-palaeocene clastic-carbonates and turbidites (šikić et al., 1979). the neogene and quaternary rock succession either rest unconformably on palaeozoic-mesozoic rocks or are tectonically superimposed upon them (fig. 1d). the ophiolitic mélange of mt. medvednica exhibits a block-in-matrix fabric typical of subduction-related tectonic mélanges (festa et al., 2010). it is composed of a pervasively sheared and fine-grained shaly-silty matrix that incorporates metre to kilometre-sized fragments and slices of mesozoic greywacke, shale, chert, limestone and igneous rocks (peri dotite cumulate, gabbro, dolerite dyke, and basalt) (slovenec & lugović, 2008, 2009; slovenec et al., 2010). the magmatic components show distinct geochemical affinities in line with their geotectonic settings of origin (within-plate, mid-ocean ridge, island arc, back-arc), which existed from the illyrian to the late oxfordian (slovenec & lugović, 2009; slovenec et al., 2010). 3. materials and analytical techniques the research area includes three locations where rock samples were taken for further analytical procedures (fig. 1d). following the petrographic microscopy investigation, nine representative rock samples were chosen for further analysis (table 1). the classification of the pyroclastic rocks was based on the scheme proposed by schmid (1981). seven whole-rock samples were selected for chemical analysis wich were carried out by icp-oes for major elements, and icp-ms for trace elements at actlab laboratories (ancaster on, canada). bulk-rock powders for chemical analyses were obtained from rock chips free of veins and amygdales. samples with calcite -filled amygdals were dissolved in diluted hcl. the icp-ms measurements were performed on 0.2 g of sample, which followed a lithium metaborate/tetraborate fusion and diluted nitric acid digestion. loss on ignition (loi) was acquired by weight difference, after ignition at 1000 °c. major and trace elements concentrations were measured using usgs bhvo-2, w-2 and bir-1 reference materials with accuracy and precision better than ±1% and ±5%, respectively. it is 3σ at 10 times detection limit. detection limit: tio2, mno = 0.001 wt.%; sio2, al2o3, fe2o3, mgo, cao, na2o, k2o, p2o5 = 0.01 wt.%; lu = 0.002 ppm; eu = 0.005 ppm; ta, pr, sm, gd, ho, er, yb, u = 0.01 ppm; th, la, ce, nd, tm = 0.05 ppm; cs, hf = 0.1 ppm; nb = 0.2 ppm; y = 0.5 ppm; sc, rb, zr = 1 ppm; sr = 2 ppm; ba = 3 ppm; v, pb = 5 ppm; cr, ni = 20 ppm. the quality of the measurements was checked by replicating the analysis on ~12% of the samples. x-ray diffraction (xrd) analyses were performed on a set of five representative samples. sample preparation included an initial material powdering in an agate mortar prior to measurements. the measurements were undertaken at texas tech university's geosciences clay laboratory (lubbock tx, united states) using a bruker d8 advance diffractometer. the xrd procedure included a step scan in the bragg-brentano geometry with cukα radiation (40 kv and 40 ma). analyzed material was scanned for 1.8 s per 0.02°, from 3° to 70 °2θ. the interpretation of xrd traces was conducted using the bruker eva software coupled with the pdf4 database released by the international centre for diffraction data. 4. results 4.1. geology of the study area the investigated pyroclastic rocks, which outcrop along the northern slopes of mt. medvednica in the area of the podbreg locality, are incorporated as hectometre-sized blocks in the ophiolitic mélange (fig. 1d). these rocks consist of lapilli tuffs (figs. 1e, f) and predominantly volcanic agglomerates/breccias (fig. 1g). the lapilli tuffs are characterized by a tuffaceous matrix containing angular to weakly rounded lithoclast fragments (basalt; fig. 1f) up to 2 cm in size and subordinate crystal clasts (pyroxene and plagioclase). weakly rounded volcanic fragments and well-rounded volcanic bombs, formed through rapid cooling during eruption, are composed of basaltic lava up to 20 cm in size and embedded in the tuffaceous matrix (fig. 1g). the tuffaceous matrix has undergone significant postconsolidation alterations and surface weathering. 4.2. petrography the analyzed rocks are represented by lapilli tuffs and volcanic bombs. the latter are composed of basaltic lavas charactable 1: overview of the analyzed rock samples sample rock type pb-1 lt pb-2 lt pb-3 lt pb-4 lt pb-4a lt pb-5 lt pb-7 lt pb-21 lt pb-71 lt xrd anal. + + + + + icp-oes/ms anal. + + + + + + ba = basalt (clast in tuff), lt = lapilli tuff. g eologia c roatica 59slovenec et al.: middle triassic basaltic pyroclastic rocks from the mt. medvednica ophiolitic mélange (nw croatia): petrology, geochemistry ... terized by porphyritic structure and almond-shaped texture (figs. 2a, b). the phenocrysts are magmatic, idiomorphic, homogeneous, prismatic, augitic, clinopyroxene, (shows yellow interference colour of the 2nd order, optically positive with 2v of about 60o, high relief, colourless and no pronounced pleochroism), and platy plagioclase, measuring up to 2.5 mm in size. figure 1: (a) geotectonic sketch map of the major tectonic units (simplified after schmid et al., 2008, 2020). legend: 1 = bükk, jadar, kopaonik; 2 = ophiolites oceanic accretionaly prism: meliata, darnó-szarvaskö, dinaric, western vardar, mirdita; 3 = pre-karst & bosnian flysch; 4 = mt. medvednica. (b) geological sketch map of the croatian part of the zagorje-mid-trandanubian zone (slightly modified after pamić & tomljenović, 1998). legend: 1 = quaternary and neogene fill of the pannonian basin; 2 = upper cretaceous-palaeocene flysch; 3 = ophiolitic mélange (kalnik unit); 4 = upper triassic platform carbonates; 5 = upper palaeozoic and triassic clastics and carbonates interlayered with volcanics and tuffs; 6 = palaeozoic-triassic metamorphic complex (medvednica unit). (c) geographical location of the study area (gray shaded). (d) simplified geological map of mt. medvednica (slightly modified after halamić, 1998). legend: 1 = neogene and quaternary sedimentary rocks; 2 = late cretaceous-palaeocene flysch including senonian carbonate breccias; 3 = ophiolitic mélange with blocks of: 4 = middle triassic radiolarites, shales, limestones, pyroclastites and basalts (black fields), 5 = middle jurassic radiolarites, shales and basalts (dark gray fields), 6 = alb-cenomanian limestones and clastic rocks (shale, siltite and sandstone); 7 = lower cretaceous metamorphic complex; 8 = reverse or thrust faults; 9 = normal faults; 10 = geological contact line; 11 = sample locations: 1 = pb-1, pb-2, pb-3, pb-4, pb-4a, pb-5; 2 = vs7, vs-21; 3 = vs-71. field occurrence of the (e-f) basaltic lapilli tuff, (g) aglomerates from the mt. medvednica ophiolitic mélange (location 1). g eo lo gi a c ro at ic a 60 geologia croatica 77/2 the groundmass is composed of volcanic glass devitrified to varying degrees and needle-like microlites of plagioclase. the modal composition includes clinopyroxene (35–50 vol.%), plagioclase (35–45 vol.%) and volcanic glass (20–25 vol.%). the phenocrysts crystallized slowly at deeper levels, unlike the needle-like microlites in the groundmass, which belong to second-generation minerals and crystallized at shallower parts of the flows. occasional clustering of phenocrysts in aggregates gives the structure a glomeroporphyritic characteristic. a typical feature of these lavas is the dominance of rounded to ellipsoidal monomineralic calcite and subordinate chlorite nodules, each up to 1.2 mm in size, which constitute the matrix filler of the rock (figs. 2a, b). the lapilli tuffs correspond to pyroclastics: (a) juvenile in origin, formed during lava eruption, consisting of fragments of cooled lava and phenocrysts formed prior to the eruption (fig. 2c), and (b) cognate in origin, formed by crushing of older lavas during a new eruption (fig. 1f). lithoclastic-vitrophyric varieties of these basic tuffs with vitriclastic structures and homogeneous, occasionally fluidal textures are predominantly present (figs. 2c, d). the content of crystal clasts within samples in the glassy groundmass is not uniform and is mostly represented by euhedral platy plagioclases up to 0.5 mm in size (fig. 2c). crystal clasts, as well as fragments of volcanic glass and fine ash powder from the groundmass, are the products of approximately simultaneous crystallization. the volcanic glass is significantly devitrified into chlorite, and calcitization of the tuffs is a common consequence of the alteration processes (figs. 2c, d). x-ray diffraction traces show the mineral composition of lapilli tuffs to be largely composed of albite, calcite, analcime, and minor titanite, chlorite, 10å phyllosilicate, and other phases (table 2). however, basaltic bombs, in addition to all the aforementioned phases feature the presence of clinopyroxene. finally, chlorite-smectite (c-s) intermediates seem to be the major alteration products of the vitreous component in both studied lithotypes. while chlorite-rich c-s is clearly of hydrothermal origin (šegvić et al., 2023), relative intensities of the 002 reflection at ~7.1 å and the 001 reflection at 14.1-14.3 å of such c-s (weaver, 1956), are taken as evidence of chlorite vermiculitization which took place during oxidative dissolution (gu et al., 2020; krzesińska et al., 2021), following the emplacement of the analyzed rocks. further weathering likely led to c-s dissolution and emergence of illite and illitesmectite interlayers as documented in sample pb-1 (table 2). figure 2. photomicrographs of thin-sections of the mt. medvednica basaltic pyroclastic rocks: (a-b) lava from a volcanic bomb (sample pb-4a), (c) lapilli tuff (sample vs-7) and (d) tuff matrix (sample pb-5). mineral abbrevations after whitney & evans (2010): cpx = clinopyroxene; cal = calcite; chl = chlorite; pl = plagioclase; vg = volcanic glass. g eologia c roatica 61slovenec et al.: middle triassic basaltic pyroclastic rocks from the mt. medvednica ophiolitic mélange (nw croatia): petrology, geochemistry ... 4.3. bulk rock chemistry the chemical composition of the studied rocks samples is detailed in table 3. the examined rocks are characterized by a high content of tio2 (1.85-2.28 wt.%) and cao (> 7.5 wt.%) and also high loss on ignition (loi = 6.02-13.30 wt.%), moderately low content of al2o3 (10.22-13.01 wt.%), and a relatively stable mg# in the range of 55-67 wt.%, corresponding to analogous effusive rocks of mts. medvednica, samoborska gora, and kalnik (slovenec et al., 2010, 2011). the mobility of the analyzed elements in the investigated rocks of mt. medvednica was assessed by plotting their concentrations against zr as a differentiation index (fig. 3). except for tio2, k2o and p2o5, which positively correlate with zr, other major elements, as well as large ion lithophile elements (lile; cs, rb, ba, sr), and transitional metals (v, cr, ni), show no correlation, indicating significant mobilization during deuteric alteration. this renders these elements unreliable for petrogenetic constraints. however, high field strength elements (hfse) such as ti, th, hf, nb, ta, p, and y, and rare earth elements (ree) exhibit a good magmatic correlation with the differentiation index. they were, therefore, used for geochemical and petrogenetic interpretation, a method successfully applied to similar mafic rocks (e.g. pearce & norry, 1979). on the zr/tio2 vs. nb/y diagram, utilized for the classification of altered extrusive rocks, the analyzed rocks correspond to alkali basalts (fig. 4). figure 5a illustrates the element spider diagram normalized to n-morb values for the middle triassic pyroclastic rocks of mt. medvednica. overall, these patterns exhibit a smooth profile characterized by a gradual enrichment in the th to lu segment, as well as slightly positive p anomalies. these characteristics of the studied pyroclastic rocks closely resemble the patterns observed in the rift related within-plate alkali basalts (wpab), and they bear a striking resemblance to the patterns of average ocean island basalts (oib) (fig. 5a). however, cs, ba, rb, k and sr show selective mobilization of these elements. chondrite normalized ree patterns of the studied rocks are displayed in figure 5b. the ree patterns show a higher enrichment of lree/hree [(la/lu)cn = 13.9-16.1] compared to the rift related alkali basalts, as well as to the alkaline basalts of the nearby medvednica, samoborska gora and kalnik mountains [(la/lu)cn = 5.3-12.8; slovenec et al., 2010, 2011; fig. 5b]. these rocks are characterized by either the absence of, or presence of an extremely small positive eu anomaly (eu/eu* = 1.00-1.06) typical for fractionation of plagioclase or its low accumulation. all samples have lucn < 10 which may indicate residual garnet (spath et al., 2001). table 2: xrd analyses of the basaltic pyroclastic rocks from the mt. medvednica ophiolite mélange sample rock type ab cpx chl c-s cal tit anl ms/iii i-s qtz fe-oxide ap pb-1 lapilli tuff ++ + + ++ + + + pb-2 lapilli tuff ++ + ++ + pb-3 lapilli tuff ++ ++ ++ + + + pb-4 basalt ++ ++ ++ ++ + ++ + pb-5 lapilli tuff ++ + ++ ++ ++ ++ + + abbreviations after whitney & evans (2010): lt – lapilli tuff; ba – basalt; qtz – quartz; ab – albite; chl – chlorite; cal – calcite; anl – analcime; ms – muscovite; ill – illite; ap – apatite; c-s – chlorite-smectite; i-s – illite-smectite; ++ – indicates major phases, + – indicates minor phases table 3: chemical analyses of basaltic pyroclastic rocks from the mt. medvednica ophiolite mélange sample pb-2 pb-4a pb-5 vs-7 vs-21 vs-71 rock type lt ba lt lt lt lt sio2 49.89 47.52 46.56 50.21 47.34 47.82 tio2 1.96 2.28 2.18 1.85 2.31 2.18 al2o3 10.52 11.65 12.14 10.22 12.96 13.01 fe2o3 total 6.88 8.34 8.45 6.23 8.81 8.24 mno 0.18 0.15 0.15 0.18 0.15 0.16 mgo 4.11 7.87 7.68 4.05 7.14 7.43 cao 8.29 8.80 7.87 11.36 10.22 8.66 na2o 2.95 2.11 2.01 3.05 3.21 2.91 k2o 0.86 1.38 1.33 0.88 1.06 0.99 p2o5 0.45 0.47 0.54 0.44 0.48 0.51 loi 13.30 8.80 10.00 10.06 6.02 7.95 total 99.39 99.37 98.91 98.53 99.70 99.86 mg# 54.9 66.7 66.2 59.1 64.5 65.4 cs 0.6 5.6 6.2 0.7 4.6 6.4 rb 21 38 32 24 34 38 ba 104 266 247 128 286 261 th 4.99 5.39 5.78 4.93 5.21 5.77 ta 3.00 3.29 3.29 3.01 3.24 3.28 nb 41.5 53.0 52.1 45.3 49.4 52.6 sr 197 181 161 202 214 173 zr 207 247 238 198 221 217 hf 5.0 5.6 5.7 5.1 5.3 5.5 y 23.2 24.1 24.5 22.1 23.9 25.2 sc 12 23 23 14 16 24 v 144 197 208 141 152 210 cr 40 340 300 41 162 296 ni 30 130 140 29 98 122 la 30.4 33.3 34.7 31.1 33.7 34.8 ce 71.6 76.8 80.2 72.4 75.6 79.7 pr 8.24 9.09 9.71 8.12 8.98 9.21 nd 32.3 34.3 37.1 32.1 33.9 36.2 sm 6.15 6.66 6.93 6.01 6.31 6.68 eu 1.96 2.07 2.09 1.99 2.01 2.06 gd 5.27 5.14 5.43 5.20 5.19 5.37 tb 0.79 0.74 0.78 0.81 0.77 0.79 dy 4.06 4.30 4.53 4.01 4.20 4.51 ho 0.75 0.75 0.82 0.74 0.76 0.80 er 1.91 2.02 2.15 1.94 1.99 2.09 tm 0.251 0.268 0.276 0.258 0.261 0.273 yb 1.47 1.60 1.52 1.49 1.51 1.56 lu 0.227 0.243 0.240 0.231 0.238 0.236 major elements in wt.%, trace elements in ppm. loi = loss on ignition at 1100 °c. ba = basalt (clast in tuff), lt = lapilli tuff. mg# = 100*molar mgo/(mgo + feototal). g eo lo gi a c ro at ic a 62 geologia croatica 77/2 5. discussion the hectometre-scale blocks of the investigated volcaniclastic rocks included into the mélanges of mt. medvednica represent the sole known pyroclastic derivatives of the middle triassic alkali volcanic activity in the southwestern part of the zagorjemid-transdanubian zone. this event has primarily produced basaltic pillow lavas, indicating its effusive submarine nature during the late anisian to early ladinian period (halamić et al., 1998; slovenec et al., 2010, 2011; kiss et al., 2012). however, the presence of alkali volcanic agglomerates and lapilli tuffs on mt. medvednica, which outcrop in the same studied area together with the geochemically identical alkali basaltic pillow lavas of known middle triassic (illyrianfassanian?) age (halamić et al., 1998), suggests the oc currence of explosive submarine events during the late anisian -early ladinian? stages. this is further supported by the abundance of rounded vesicles in the investigated basaltic volcanic bombs, suggesting rapid submarine crystallization due to the sudden cooling of magma as pressure decreased during its ascent and arrival at the surface, exposing the lava to significant gas expansion (bloomer, 1994). 5.1. petrogenetic and tectonomagmatic significance mesozoic alkali basalts, commonly found today as blocks preserved in ophiolitic mélanges across the broader mediterranean region, are seen as remnants of either (a) intraoceanic islands (oi) and seamounts (e.g. saccani & photiades, 2005; monjoie et al., 2008; sayit & göncüoglu, 2009), or (b) continental rifts (cr) (e.g. fitton, 2007). the composition of continental rift basalts is akin to oi basalts; however, these rocks result from the continental break-up which preceded the formation of the nascent oceanic crust (bortolotti et al., 2009; koglin et al., 2009). petrographic, xrd and geochemical analysis revealed significant sea-floor hydrothermal alterations in the rocks, confirmed by high loss on ignition and selective mobilisation figure 3. variation diagrams for selected elements with zr s index of differentiation for the basaltic pyroclastic rocks from the mt. medvednica ophiolite mélange. figure 4. nb/y – zr/tio2*10-4 classification diagram (pearce, 1996) for the basaltic pyroclastic rocks from the mt. medvednica ophiolitic mélange. g eologia c roatica 63slovenec et al.: middle triassic basaltic pyroclastic rocks from the mt. medvednica ophiolitic mélange (nw croatia): petrology, geochemistry ... of lile (table 3; polat et al., 2002; polat & hofmann, 2003). here reported post-magmatic parageneses (table 2) are in line with those of similar hydrothermally altered mafic rocks from the area (slovenec et al., 2012; šegvić et al., 2023). the formation of the investigated pyroclastic rocks is associated with alkali suites (nb/ > 1 and high ti/v = 62-91; shervais, 2023) formed in divergent within-plate settings (fig. 6a). however, to reliably distinguish tectonomagmatic settings of origin for basaltic rocks where their geochemical characteristics exhibit features of continental ridge basalt (crb) and ocean island basalt (oib), the la/10 vs. nb/8 vs. y/15 diagram (cabanis & lecolle, 1989) and the multielement ratios discriminate function analysis proposed by agrawal et al. (2008) were successfully utilized. based on these criteria, the analyzed pyroclastics from mt. medvednica, along with their volcanic equivalents represented by the basaltic lavas of mts. medvednica, samoborska gora, and kalnik, unequivocally originated in the same geotectonic area of an intracratonic rift (figs. 6b, c). therefore, it seems more fitting to interpret these rocks as volcanic or volcaniclastic deposits in a pre-ophiolitic continental rift basin, rather than considering them as the remains of an intraoceanic island or seamounts. although the investigated alkali pyroclastic rocks share the same geochemical characteristics with illyrian-fassanian basaltic lavas of mts. medvednica, samoborska gora, and kalnik, there are certain minor differences in their source composition. specifically, higher values of key discriminative ratios [(th/yb)pm = 19-22, (ta/yb)pm = 24-26, and la/yb = 21-23], along with a lesser degree of partial melting (fig. 7) in the pyroclastic rocks of mt. medvednica compared to basaltic lavas [(th/yb)pm = 7-16, (ta/yb)pm = 10-18, and la/yb = 8-13; slovenec et al., 2010, 2011], indicate their more primitive nature and suggest the generation of pyroclastics immediately preceding the formation of basaltic lavas. consequently, it can be inferred that explosive volcanism recorded on mt. medvednica directly preceded the dominant effusive volcanism that resulted in the formation of basaltic lavas on mts. medvednica, samoborska gora, and kalnik, during the late anisian-early ladinian stages. the very low la/ta ratio (< 10.5) observed in the investigated pyroclastics, which is significantly lower than the values for uncontaminated continental rift basalt (crb) (la/ ta < 22; e.g. fitton et al., 1988; hart et al., 1989), suggests that these pyroclastics represent uncontaminated melts erupted through highly thinned continental crust. the diminished relative abundance of hree in these alkali pyroclastic rocks indicates residual garnet in the mantle source (e.g. spath et al., 1996). the analyzed pyroclastic rocks reflect melts derived from a primitive oib-type mantle plume source, which experienced around 4-4.5% of partial melting (fig. 7). this percentage is slightly lower than that of the mantle source for mts. medvednica, samoborska gora, and kalnik alkali basaltic lavas. 5.2. geodynamic significance the origin of the investigated pyroclastic rocks of mt. medvednica can be explained by two geodynamic models based on two distinct palaeogeographic reconstructions of geological events in the wider mediterranean area during the middle triassic. the first model was introduced by stampfli & borel (2002, 2004) and stampfli & hochard (2009), whilst the second one was presented by van hinsbergen et al. (2020). the geodynamic model based on the palaeogeographic reconstructions of stampfli & borel (2002, 2004) and stampfli & hochard (2009) involves the palaeotethyan middle triassic northward subduction under an active margin of laurentia (fig. 8a). along the palaeotethyan nortwestern margin, extensional tectonism occurred as a result of asthenospheric passive upwelling. this, in turn, caused the emergence of an oib-type mantle plume within the ensialic back-arc lithosphere. the rise of this primitive mantle dome was attributed to adiabatic decompression along a network of subparallel faults, as outlined by slovenec & šegvić (2021). this process was further facilitated by the substantial northeastfigure 5. (a) n-morb normalized multielement patterns (sun & mcdonough, 1989); (b) chondrite normalized ree patterns (taylor & mclennan, 1985) for the basaltic pyroclastic rocks from the mt. medvednica ophiolite mélange. fields for alkali basalts from the mts. medvednica, kalnik and samoborska gora ophiolitic mélange (slovenec et al., 2010, 2011), and for the average composition of within-plate alkali basalts (wpab; wilson, 1989) and ocean island basalts (oib; sun & mcdonough, 1989) plotted for correlation constraints. g eo lo gi a c ro at ic a 64 geologia croatica 77/2 ward roll-back and retreat of the palaeotethyan subducted slab (slovenec et al., 2010). ultimately, this sequence of events resulted in proto back-arc rifting within the continental crustal stable mass. this most likely happened behind the pericontinental volcanic arc thus giving rise to the maliak back-arc rift within the emerging northwestern segment of neotethys. (fig. 8a). in this region, the phenomenon of back-arc rifting resulted in the formation of uncontaminated alkali basaltic lavas and pyroclastites, ranging from primitive to moderately evolved (oib-type). these volcanic materials are characterized by their absence of subduction components and crustal contamination. therefore, the investigated pyroclastic rocks of mt. medvednica, along with their volcanic outflows from the southwest segment of the zmtdz, likely represent the last stage of spreading in a mature intracontinental rift basin. however, these alkali rocks, not qualifying strictly as ophiolitic rocks, also mark the initial (proto) phase of the opening of the future northwestern part of neotethys, (the meliata-maliakpindos ocean system), as well as epidote-bearing albite granite from mt. medvednica (balen et al., 2022). this likely occurred before the formation of the nascent oceanic crust during the upper triassic (slovenec et al., 2011). figure 6. discrimination diagrams for the basaltic pyroclastic rocks from the mt. medvednica ophiolitic mélange. (a) simplified thn – nbn diagram (saccani, 2015). pm = primitive mantle. th and nb normalized to the n-morb composition (sun & mcdonough 1989). ab = alkali basalts, babb = back-arc basin basalts, bon = boninites, cab = calc-alkali basalts, iat = island-arc tholeiites, n-morb = normal mid-ocean ridge basalts, e-morb = enriched morb. (b) la/10 – nb/8 – y/15 diagram (cabanis & lecolle, 1989). 1 = volcanic arc basalts; 2 = continental basalts; 3 = oceanic basalts; 1a = calc-alkali basalts (cab); 1b = calc-alkali basalts and island-arc tholeiites (cab, iat); 1c = island-arc tholeiites (iat); 2a = within-plate basalts (wpb); 2b = back-arc basin basalts (babb); 3a = intracontinental rift alkali basalts (icrab); 3b = enriched morb (e-morb); 3c = weakly enriched morb (e-morb); 3d = normal mid-ocean ridge basalts (n-morb). (c) df1 – df2 diagram (agrawal et al., 2008; df1 = 0.5533 loge (la/th) + 0.2173 loge (sm/th) – 0.0969 loge (yb/th) + 2.0454 loge (nb/th) – 5.6305; df2 = -2.4498 loge (la/th) + 4.8562 loge (sm/th) – 2.1240 loge (yb/th) – 0.1567 loge (nb/th) + 0.94). iab – island-arc basalts; oib – ocean-island basalts; crb – continental rift basalts. fields for alkali basalts from the mts. medvednica, kalnik and samoborska gora ophiolitic mélange (slovenec et al., 2010, 2011) plotted for correlation constraints. g eologia c roatica 65slovenec et al.: middle triassic basaltic pyroclastic rocks from the mt. medvednica ophiolitic mélange (nw croatia): petrology, geochemistry ... according to the geodynamic model relying on the palaeogeographic reconstruction presented by van hinsbergen et al. (2020), the initiation of the balkan neotethys ocean can be attributed to the west-oriented subduction of the balkan palaeotethys ocean under the northeastern margin of greater adria/dacia. during this process, there was a successively northeastward roll-back and retreat of the subducted sinking slab of the balkan palaeotethys (fig. 8b). these intense processes of slab retreat freed up significant space in the asthenosphere, allowing for uninterrupted upwelling of asthenospheric mantle during the upper anisian. this upwelling mantle was characterized by oib-type mantle plumes, leading to the formation of the proto back-arc balkan neotethys rift accompanied by intense volcanism. similar to the previous geodynamic model, this volcanism is marked by eruptions and effusions of primitive to moderately evolved (oib-type) uncontaminated alkali basaltic pyroclastites and lavas (fig. 8b), now archived in the ophiolitic mélange of the southwest segment of the zmtdz (figs. 1b-d). subsequent extensional events during the upper triassic and middle jurassic were followed by continuous magmatism and generation of the oceanic lithosphere within the balkan neotethys ocean (slovenec & šegvić, 2023). however, apart from the two geodynamic models proposed for events on the northeastern margin of adria (i.e. dinarides, southern alps and alcapa) during the middle triassic, it is also possible to assume the one proposed by lustrino et al. (2019), casseta et al. (2019), de min et al. (2020) and velicogna et al. (2023) is credible. they associate magmatism with complex mantle heterogeneities or as an inheritance from previous tectonic events, discarding the hypothesis that an active subduction occurred in adria during the triassic. in this sense, the mantle source was variably metasomatized, and the magmatism was probably triggered by the extensional and transtensional tectonics related to the rifting system. the subduction signatures of the magmas were probably inherited from the subduction events that occurred during the variscan or even older orogenic cycles. 6. conclusions • in the ophiolitic mélange of medvednica mt., situated in the southwestern segment of the zagorje-mid-transdanubian zone, hectometre blocks of middle triassic (late anisianearly ladinian?) mafic pyroclastic rocks (volcanic agglomerates/breccias and lapilli tuffs) were discovered for the first time. • these pyroclastic derivatives of alkali within-plate basaltic lavas, which outcrop in the same studied area, indicate the occurrence of explosive events preceding the dominant effusive submarine volcanism. • the mineral composition and chemistry of the rocks reflects significant sea-floor hydrothermal alterations. figure 7. petrogenic model for the basaltic pyroclastic rocks from the mt. medvednica ophiolitic mélange. partial melting line for moderately enriched mantle source (oib-like) (la = 1.5 ppm, yb = 0.5 ppm). model parameters = garnet-lherzolite source (ol60.1-opx18.9-cpx13.7-gt7.3), melting proportion = ol1.3-opx8.7-cpx36-gt54, distribution coefficients are from kostopoulos & james (1992). fractional crystallization lines: initial magma = 4% and 6% melting of the moderately enriched mantle source, fractionated mineral assemblage = ol30-cpx40-pl30, distribution coefficients are from chen et al. (1990). fields for alkali basalts from the mts. medvednica, kalnik and samoborska gora ophiolitic mélange (slovenec et al., 2010, 2011) plotted for correlation constraints. figure 8. schematic geodynamic sketch model of the tectonic setting of the investigated mt. medvednica basaltic pyroclastic rocks and formation of the back-arc rift in accordance with the palaeogeographic reconstruction: (a) stampfli & borel (2002, 2004) and stampfli & hochard (2009) and (b) van hinsbergen et al. (2020) (slightly modified after slovenec & šegvić, 2023). ab = alkaline basalts/pyroclastites, cab = calc-alkaline and shoshonitic basalts/volcaniclastites, oib = ocean island basalts. g eo lo gi a c ro at ic a 66 geologia croatica 77/2 • the formation of studied pre-ophiolitic pyroclastics is associated with an intracontinental rift setting and reflects melts derived from an oib-type enriched mantle plume source, which experienced around 4-4.5% of partial melting. • the investigated pyroclastites were most likely generated during the late anisian-early ladinian? along the continental margin of palaeotethys through the proto back-arc rifting of continental lithosphere (adria plate), leading to the formation of the maliak/balkan neotethys rift in the emerging northwestern segment of neotethys. these events, which do not indicate the existence of active subduction in the adria plate, immediately preceded the generation of the initial neotethyan oceanic lithosphere during the upper triassic. acknowledgment this work was funded by the croatian science foundation under the project “revealing the middle triassic palaeotethyan geodynamics recorded in the volcano-sedimentary successions of nw croatia” (ip-2019-04-3824). the authors extend their gratitude to radovan filjak for his assistance during the fieldwork. critical comments and constructive reviews by two anonymous reviewers, as well as editorial handling and review by dražen balen have contributed significantly to the quality of the manuscript. references agrawal, s., guevara, m. & verma, s.p. (2008): tectonic dis crimination of basic and ultrabasic volcanic rocks through log-transformed ratios of immobile trace elements.– int. geol. rev., 50, 1057–1079. doi: 10.2747/0020-6814.50.12.1057 babić, lj., hochuli, p.a. & zupanič, j. (2002): the jurassic ophiolitic mélange in the ne dinarides: dating, internal structure and geotectonic implications.– eclogae geol. helv., 95, 263–257. balen, d., schneider, p., opitz, j., massonne, h. (2022): pres sure– temperature–time constraints on the evolution of epidote-bearing albite granite from mt. medvednica (croatia): further evidence of the middle triassic opening of the neotethys ocean.– geologica carpathica, 73, 411–433. doi: 10.31577/geolcarp.73.5.2 belak, m., pamić, j., kolar-jurkovšek, t., pecskay, z. & karan, d. (1995): alpine low-grade regional metamorphic complex of mt. medvednica (northwest croatia).– in: vlahović, i., velić, i. & šparica, m. (eds.): proceed., 1st croat. geol. congr. inst. geol., zagreb, 67–70. belak, m., slovenec, da., kolar-jurkovšek, t., garašić, v., pécskay, z., tibljaš, d. & mišur, i. (2022): low-grade metamorphic rocks of the tethys subduction– collision zone in the medvednica mt. (nw croatia).– geol. carpathica, 73, 207–229. doi: 10.31577/ geolcarp.73.3.3 bloomer, s.h. (1994): origin of segregation vesicles in volcanic rocks from the lau basin, leg 135.– in: hawkins, j., parson, l. & allan, j. et al. (eds.): proceed. of the ocean drilling program, scientific results, college station, tx (ocean drilling program), 135, 717– 735. doi: 10.2973/odp.proc.sr.135.127.1994 bortolotti, v., carras, n., chiari, m., fazzuoli, m., marcucci, m., nirta, g., principi, g. & saccani, e. (2009): the ophiolite-bearing mélange in the early tertiary pindos flysch of etolia (central greece).– ofioliti, 34, 83–94. cabanis, b. & lecolle, m. (1989): le diagramme la/10-y/15-nb/8: un outil pour la discrimination des series volcaniques et la mise en evidence des processus de mélange et/ou de contamination crustale.– c.r. acad. sci. serr. ii, 309, 2023–2029. casetta, f., ickert, r.b., mark, d.f., bonadiman, c., gia comoni, p. p., ntaflos, t. & coltorti, m. (2019): the alkaline lamprophyres of the dolomitic area (southern alps, italy): markers of the late triassic change from orogenic like to anorogenic magmatism.– j. petrol., 60, 1298.10. doi: 10.1093/petrology/egz031 chen, c.y., frey, f.a. & garcia, m.o. (1990): evolution of alkalic lavas at haleakala volcano, east maui, hawaii.– contr. miner. petrol., 105, 197–218. doi: 10.1007/bf00678986 de min, a., velicogna, m., ziberna, l., chiaradia, m., alberti, a. & marzoli, a. (2020): triassic magmatism in the european southern alps as an early phase of pangea break-up.– geol. mag., 157, 11, 1800–1822. doi: 10.1017/s0016756820000084 festa, a., pini, g.a., dilek, y. & codegone, j. (2010): mélanges and mélange-forming processes: a historical overview and new concepts.– international geology review, ifirst article, 1–66. doi: 10.1080/00206810903557704 fitton, j.g. (2007): the oib paradox.– in: foulger, g.r. & jurdy, d.m. (eds.). plates, plume and planetary processes.– geol. soc. am., spec. paper, 430, 387–412. doi: 10.1130/2007.2430(20) fitton, j.g., kempton, d., ormerod, d.s. & leeman, w.p. (1988): the role of lithospheric mantle in the generation of late cenozoic basic magmas in the western united states.– j. petrol. spec. lithosphere issue, 331–349. doi: 10.1093/petrology/special_volume.1.331 gu, x., rempe, d.m., dietrich, w.e., west, a.j., lin, t.-c., jin, l. & brantley, s.l. (2020): chemical reactions, porosity, and microfracturing in shale during weathering: the effect of erosion rate.– geochimica et cosmochimica acta, 269, 63–100. doi: 10.1016/j.gca.2019.09.044 haas, j., mioč, p., pamić, j., tomljenović, b., árkai, p., bérczi-makk, a., koroknai, b., kovács, s. & r.-felgenhauer, e. (2000): complex structural pattern of the alpine-dinaridic pannonian triple junction.– int. j. earth sci., 89, 377–389. doi: 10.1007/ s005310000093 halamić, j. (1998): lithostratigraphy of jurassic and cretaceous sediments with ophiolites from the mts. medvednica, kalnik and ivanščica. phd thesis, faculty of science (in croatian, english summary).– university of zagreb, zagreb, 188 p. halamić j., slovenec da. & kolar-jurkovšek, t. (1998): triassic pelagic limestones in pillow lavas in the orešje quarry near gornja bistra, medvednica mt. (northwest croatia).– geol. croatica, 51, 33–45. halamić, j., goričan, š., slovenec, da. & kolar-jurkovšek, t. (1999): middle jurassic radiolarite-clastic succession from the medvednica mt. (nw croatia).– geol. croat., 52, 29–57. hart, w.k., wolde, g.c., walter, r.c. & mertzman, s.a. (1989): basaltic volcanism in ethiopia: constraints on continental rifting and mantle interactions.– j. geophys. res., 94, 7731-7748. doi: 10.1029/ jb094ib06p07731 kiss, g., molnár, f., palinkaš, l., kovács, s. & horvatović. h. (2012): correlation of triassic advanced riftingrelated neotethyan submarine basaltic volcanism of the darnó unit (ne-hungary) with some dinaridic and hellenidic occurrences on the basis of volcanological, fluid–rock interaction, and geochemical characteristics.– int. j. earth sci., 101, 1503–1521. koglin, n., kostopoulos, d. & reischmann, t. (2009): the lesvos mafic–ultramafic complex, greece: ophiolite or incipient rift?– lithos, 108, 243–261. doi: 10.1016/j.lithos.2008.09.006 kostopoulos, d.k. & james, s.d. (1992): parameterization of the melting regime of the shallow upper mantle and the effects of variable lithospheric stretching on mantle modal stratification and trace element concentrations in magmas.– j. petrol., 33, 665–691. doi: 10.1093/petrology/33.3.665 krzesińska, a.m., bultel, b., loizeau, d., craw, d., april, r., poulet, f. & werner, s.c. (2021): mineralogical and spectral g eologia c roatica 67slovenec et al.: middle triassic basaltic pyroclastic rocks from the mt. medvednica ophiolitic mélange (nw croatia): petrology, geochemistry ... (near-infrared) characterization of fe-rich vermiculite-bearing terrestrial deposits and constraints for mineralogy of oxia planum, exomars 2022 landing site.– astrobiology, 21, 997–1016. doi: 10.1089/ ast.2020.2410 lugović, b., slovenec, da., halamić, j. & altherr, r. (2007): petrology, geochemistry and geotectonic affinity of the mesozoic ultramafic rocks from the southwesternmost mid-transdanubian zone in croatia.– geol. carpathica, 58, 511–530. lustrino, m., abbas, h., agostini, s., caggiati, m., car minati, e. & gianolla, p. (2019): origin of triassic magmatism of the southern alps (italy): constraints from geochemistry and sr-nd-pb isotopic ratios.– gondwana res., 75, 218–238. doi: 10.1016/j.gr.2019.04.011 monjoie, p., lapierre, h., tashko, a., mascle, g.h., dechamp, a., muceku, b. & brunet, b. (2008): nature and origin of the triassic volcanism in albania and othrys: a key to understanding the neotethys opening?– bull. soc. géol. fr., 179, 411–425. doi: 10.2113/gssgfbull.179.4.411 pamić, j. (2002): the sava-vardar zone of the dinarides and hellenides versus the vardar ocean.– eclogae geol. helv., 95, 99–113. pamić, j. & tomljenović, b. (1998): basic geological data on the croatian part of the mid-transdanubian zone as exemplified by mt. medvednica located along the zagreb-zemplen fault zone.– acta geol. hungarica, 41, 389–400. pearce, j.a. (1996): a user’s guide to basalt discrimination diagrams. in trace element geochemistry of volcanic rocks: applications for massive sulphide exploration.– in: wyman, d.a. (ed.). short course notes 12; geological association of canada: newfoundland, nl, canada, 79–113. pearce, j.a. & norry, m.j. (1979): petrogenetic implications of ti, zr, y, and nb variations in volcanic rocks.– contrib. mineral. petrol., 69, 33–47. polat, a., hofmann, a.w. & rosing, m.t. (2002): boninite-like volcanic rocks in the 3.7–3.8 ga isua greenstone belt, west greenland: geochemical evidence for intra-oceanic subduction zone processes in the early earth.– chemical geology, 184, 231–254. doi: 10.1016/s00092541(01)00363-1 polat, a. & hofmann, a. w. (2003): alteration and geochemical patterns in the 3.7–3.8 ga isua greenstone belt, west greenland.– precambrian research, 126, 197–218. doi: 10.1016/s0301-9268(03)00095-0 saccani, e. & photiades, a. (2005): petrogenesis and tectonomagmatic significance of volcanic and subvolcanic rocks in the albanide helle nide ophiolitic mélanges.– the island arc, 14, 494–516. doi: 10.1111/j.1440 -1738.2005.00480.x saccani, e. (2015): a new method of discriminating different types of post-archean ophiolitic basalts and their tectonic significance using thnb and ce-dy-yb systematics.– geoscience frontiers, 6, 481–501. doi: 10.1016/j.gsf.2014.03.006 sayit, k. & göncüoglu, m.c. (2009): geochemistry of mafic rocks of the karakaya complex, turkey: evidence for plume-involvement in the palaeotethyan extensional regime during the middle and late triassic.– int. j. earth sci., 98, 367–385. doi: 10.1007/s00531-007-0251-6 schmid, r. (1981): descriptive nomenclature and classifcation of pyroclastic deposits and fragments: recommendations of the iugs subcommission on the systematics of igneous rocks.– geology, 9, 41–43. schmid, s.m., bernoulli, d., fügenschuh, b., matenco, l., scheffer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpine-carpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss j. geosci., 101, 139–183. doi: 10.1007/s00015-008-1247-3 schmid, s.m., fügensschuh, b. & kounov, a. et al. (2020): tectonic units of the alpine collision zone between eastern alps and western turkey.– gondwana research, 78, 308–374. doi: 10.1016/j.gr.2019.07.005 shervais, j.w. (2023): the petrogenesis of modern and ophiolitic lavas reconsidered: ti-v and nb-th.– geoscience frontiers, 13, 101319. doi: 10.1016/j.gsf.2021.101319 slovenec, da. & pamić, j. (2002): the vardar zone ophiolites of mt. medvednica located along the zagreb-zemplin line (nw croatia).– geol. carpathica, 53, 53–59. slovenec, da. & lugović, b. (2008): amphibole gabbroic rocks from the mt. medvednica ophiolite mélange (nw croatia): geochemistry and tectonic setting.– geol. carpathica, 59, 277–293. slovenec, da. & lugović, b. (2009): geochemistry and tectono-magmatic affinity of extrusive and dyke rocks from the ophiolite mélange in the sw zagorje-mid-transdanubian zone (mt. medvednica, croatia).– ofioliti, 34, 63–80. slovenec, da., lugović, b. & vlahović, i. (2010): geochemistry, petrology and tectonomagmatic significance of basaltic rocks from the ophiolite mélange at the nw external-internal dinarides junction (croatia).– geol. carpathica, 61, 273–294. doi: 10.2478/v10096-010-0016-1 slovenec, da., lugović, b., meyer, h.p. & garapić-šiftar, g. (2011): a tectono-magmatic correlation of basaltic rocks from ophiolite mélanges at the north-eastern tip of the sava-vardar suture zone, northern croatia, constrained by geochemistry and petrology.– ofioliti, 36, 77–100. slovenec, da, lugović, b., slovenec, d. (2012): secondary mineral paragenesis in the mafic extrusive rocks from the mt. medvednica ophiolite melange (croatia)/sekundarne mineralne parageneze u mafitnim ekstruzivnim stijenama iz ofiolitnog melanza medvednice (hrvatska).– rudarsko-geolosko-naftni zbornik, 25, 33–46. slovenec, da. & šegvić, b. (2021): middle triassic high-k calc-alkaline effusive and pyroclastic rocks from the zagorje-mid-transdanubian zone (mt. kuna gora; nw croatia): mineralogy, petrology, geochemistry and tectono-magmatic affinity.– geologica acta, 19, 1–23. doi: 10.1344/geologicaacta2021.19.2 slovenec, da. & šegvić, b. (2023): the evolution of the mesozoic lithosphere of northwestern neotethys: a petrogenetic and geodynamic perspective.– journal of the geological society, 181/1. doi: 10.1144/ jgs2023-132 spath, a., le roex, a.p. & duncan, r.a. (1996): the geochemistry of lavas from the comores archipelago, western indian ocean: petrogenesis and mantle source region characteristics.– j. petrol., 37, 961–991. spath a., le roex a.p. & opivo-akech n. (2001): plume lithosphere interaction and the origin of continental rift-related alkaline volcanism the chyulu hills volcanic province, soutern kenya.– j. petrol., 42, 765– 787. stampfli, g.m. & borel, g.d. (2002): a plate tectonic model for the palaeozoic and mesozoic constrained by dinamic plate boundaries and restored synthetic ocean isochrons.earth planet sci lett.– 196, 17–33. stampfli, g.m. & borel, g.d. (2004): the transmed transects in space and time: constraints on the palaeotectonic evolution of the mediterranean domain.– in: cavazza, w., roure, f., spakman, w., stampfli, g.m. & ziegler, p.a. (eds.): the transmed atlas: the mediterranean region from crust to mantle. springer verlag, 53–80. doi: 10.1007/978-3-642-18919-7_3 stampfli, g.m. & hochard, c. (2009): plate tectonics of the alpine realm.– geol. soc. london spec. publ., 327, 89–111. doi: 10.1144/sp327.6 sun, s.s. & mcdonough, w.f. (1989): chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes.– in: saunders, a.d. & norry, m.j. (eds.). magmatism in ocean basins.– geol. soc. london. spec. publ., 42, 313–345. doi: 10.1144/gsl. sp.1989.042.01.19 šegvić, b., slovenec, da. & badurina, l. (2023): major and rare earth element mineral chemistry of low-grade assemblages inform dynamics of hydrothermal ocean-floor metamorphism in the dinaridic neotethys.– geological magazine 160, 444–470. doi: 10.1017/ s0016756822001030 g eo lo gi a c ro at ic a 68 geologia croatica 77/2 šikić, k., basch, o. & šimunić, an. (1978): basic geological map of sfry 1:100.000.– zagreb sheet, inst. geol. istraž. zagreb, sav. geol. zavod, beograd. šikić, k., basch, o. & šimunić, an. (1979): basic geological map of sfry 1:100.000. sheet zagreb, geology of the zagreb sheet (in croatian, english summary).– inst. geol. istraž. zagreb, sav. geol. zavod, beograd, 81 p. tari, v. & pamić, j. (1998): geodynamic evolution of the northern dinarides and the southern parts of the pannonian basin.– tectonophysics, 297, 296–281. doi: 10.1016/s0040-1951(98)00172-3 taylor, s.r. & mclennan, s.m. (1985): the continental crust: its composition and evolution.– blackwell, oxford, 312 p. doi: 10.1017/ cbo9780511575358.014 van hinsbergen, d.j.j., torsvik, t.h., schmid, s.m., maţenco, l.c., maffione, m., vissers, r.l.m., gürer, d. & spakman, w. (2020): orogenic architecture of the mediterranean region and kinematic reconstruction of its tectonic evolution since the triassic.– gondwana research, 81, 79–229. doi: 10.1016/j.gr.2019.07.009 velicogna, m., prasek, m.k., ziberna, l., de min, a., brombin, v., jourdan, f., renne, p.r., balen, d. & marzoli, a. (2023): the norian magmatic rocks of jabuka, brusnik and vis islands (croatia) and their bearing on the evolution of triassic magmatism in the northern mediter ranean.– int. geol. rev., 65, 2558–2579. doi: 10.1080/00206814.2022.2150898 weaver, c.e. (1956): the distribution and identification of mixed-layer clays in sedimentary rocks.– american mineralogist, 41, 202–221. doi: 10.1346/ccmn.1955.0040143 whitney, d.l. & evans, b.w. (2010): abbreviations for names of rock-forming minerals.– am. mineral., 95, 185–187. doi: 10.2138/ am.2010.3371 wilson, m. (1989): igneous petrogenesis.– unwin hyman ltd., london, 466 p. doi: 10.1007/978-1-4020-6788-4 2022 | 75/special issue | 291–302| 7 figs. | 6 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction tailings are defined by lottermoser (2010) as “the processing waste from a mill, washery or concentrator that removed the economic metals, minerals, mineral fuels or coal from the mined resource”. tailings of abandoned mines often contain significant amounts of metals, which could not be recovered with the existing technology at the time of mining, were not of economic interest, or were not analyzed at that time. the latter holds true for many high-tech metals like ge, ga, in, te, bi and rare earth elements (ree). many of these metals are regarded as “critical” by the european commission. a critical raw material has a high economic importance and a high supply risk in the eu (løvik et al. 2018). this study was conducted in the frame of the ris kava reseerve project funded by the european union. the objective of the reseerve project is creating a west balkan mineral register to reduce exploration costs and investment risks in order to improve the self-supply of the european union with critical metals. this study ś main scope is a fundamental characterization of some tailings in terms of their mineralogy and content of valuable metals which could be extracted to finance a possible remediation and improve the supply of the eu with critical metals. tailings in most cases comprise small to very small particles and hence expose a very large mineral surface area to the envi preliminary chemical and mineralogical characterization of tailings from base metal sulfide deposits in serbia and north macedonia timotheus martin christoph steiner1,*, viktor bertrandsson erlandsson1, robert šajn2 and frank melcher1 1 montanuniversitaet leoben, department for applied geosciences and geophysics, peter-tunner-str. 5, 8700 leoben, austria; (viktor.erlandsson@unileoben.ac.at, frank.melcher@unileoben.ac.at, *corresponding author: timotheus.steiner@gmail.com) 2 geological survey of slovenia, dimičeva ulica 14, ljubljana; (robert.sajn@geo-zs.si) doi: 10.4154/gc.2022.22 abstract tailings of old mines often contain metals, which were not of economic interest or could not be recovered with the existing technology at the time of active mining. this is especially true for metals that often occur as by-products in cu-pb-zn-(ag-au) ores as sb, mo, ge, and in. a fundamental characterization of some tailings is presented in terms of their mineralogy and content of valuable metals which could be extracted to finance a possible remediation and improve the supply of the eu with critical metals. tailings from active and abandoned mines in serbia (bor, porphyry cu/au; krivelj, porphyry cu/au; blagodat, hydrothermal pb-zn; lece, epithermal au; rudnik, hydrothermal/skarn pb-zn) and north macedonia (sasa, pb-zn; probištip, pb-zn; bučim, porphyry cu; lojane, fault-bound vein-type low-temperature as, sb, cr at the contact of rhyolite and serpentinite) were studied. analysis for major and trace elements used a multi-method approach (lithium borate fusion and icp-ms/oes analysis, gravimetric analysis, instrumental neutron activation analysis, total digestion icp-oes, infrared spectroscopy) with mineral identification by scanning electron microscopy. concentrations of the major commodity elements (cu, pb, zn, au, ag) varies within several orders of magnitude depending on mineralogy and ore type. critical metals (co, ga, ge, sb) contents are low with some exceptions. some tailings contain moderate to elevated potentially toxic element levels (as, cd, pb, tl). for the sample from probištip which yielded the highest valuable metal concentrations (>5000 ppm pb, 4020 ppm zn), a heavy mineral concentrate of the sand size fraction (0.06 mm to 0.5 mm) was produced and analyzed by sem and la-icp-ms for additional rare phases and trace elements. in all tailings studied, additional milling would be needed to separate ore from gangue minerals. increasing metal prices might facilitate feasibility studies for some of the localities in the future, despite the limited quantitative information about the characterized tailings. ronment. this mineral surface was mostly “fresh”, i.e., unweathered at the time of mining. this can present a hazard for the local environment, as leaching of toxic minerals and acid mine drainage can be greatly enhanced. this long ongoing weathering is also a threat to possible mining of the tailings as it may have changed the original ores significantly. alternatively, large tailings can also represent an opportunity for recovering valuable metals needed for high-tech applications. 2. study sites material from the tailings dams of the bor, krivelj, grot/blagodat, lece, rudnik (all located in serbia), and sasa, probištip, bučim and lojane (located in north macedonia) mines were collected in order to gain an initial overview of their chemical and mineralogical composition and to estimate the potential for future metal recovery. locations are shown in fig. 1, while coordinates of the sampled locations, deposit status, the surface of the tailings and the quantity stored in the tailings are listed in table 1. table 2 presents basic information on the ore deposit type, host rocks and reserves of the primary deposits related to the sampled tailing dams as provided in the literature. concerning environmental hazards, the tailings of probištip (acid mine drainage) article history: manuscript received october 30, 2021 revised manuscript accepted may 05, 2022 available online october 17, 2022 keywords: tailings, bor, krivelj, grot, blagodat, lece, rudnik, sasa, probištip, bučim, lojane mailto:frank.melcher@unileoben.ac.at g eo lo gi a c ro at ic a geologia croatica 75/special issue 292 and lojane (high concentrations of as and sb in the tailings) must be noted. the localities bor and krivelj are both part of the same deposit. 2.1. bor and krivelj the bor deposit is part of the bor metallogenetic zone and formed as a porphyry copper deposit (jelenković et al. 2016). it constitutes the type location of the bor metallogenetic zone which is part of the tethyan eurasian metallogenetic belt (janković 1977). the deposit formed in the upper cretaceous due to subduction related magmatism as part of the banatitic magmatic belt (jelenković et al. 2016 and references therein). typical ore minerals are pyrite, enargite, tetrahedrite, bornite, and chalcopyrite. the reserves of the deposit are 130.5 million figure 1. overview map of the project area in serbia and north macedonia. the geological background map showing the abbreviated formation time of the geological units is modified from the igme 5000 map (asch, 2005), details of the legend can be found there. g eologia c roatica steiner et al.: preliminary chemical and mineralogical characterization of tailings from base metal sulfide deposits in serbia and north macedonia 293 tons at 0.56 % cu, 0.24 g/t au, and 1.66 g/t ag; the inferred resources are 450.8 million tons at 0.49 % cu, 0.1 g/t au, and 1.72 g/t ag (jelenković et al. 2008). the tailings of bor (fig. 2 a, b) cover an area of 55 ha (geological survey of slovenia 2022). the krivelj mine and its tailings dam covering an area of 82 ha and are located 3 km north of the bor mine (fig. 2 c) (geological survey of slovenia 2022). 2.2. grot/blagodat the blagodat deposit is a hydrothermal-replacement pb-zn deposit hosted by granitoids, gneisses, and limestones (jelenković et al. 2008). characteristic ore minerals are galena, sphalerite, and pyrite (jelenković et al. 2008). djokić et al. (2012) describe the ore as mainly composed of quartz followed by clay minerals, calcite, siderite, feldspars, and haematite; 17 % of the ore is sulfides, mainly pyrite, sphalerite, galena, and chalcopyrite. the grot tailings dam hosts about 5.5 million tons of sand size fraction material (grain size around 0.5 mm) produced in the processing plant of the blagodat ore field, which ceased production 100 years ago (djokić et al. 2012). the tailings are heterogenous and metal contents range from 1500-18600 ppm pb, 2300-4000 ppm zn, 75-600 ppm cu, 18-158 ppm as, and 7000-10000 ppm mn, respectively (djokić et al. 2012). the tailings of grot (fig. 2 d) cover an area of 26 ha (geological survey of slovenia 2022). 2.3. lece the lece mine is situated in the lece volcanic complex in se serbia at the border of the eastern vardar ophiolite zone and the serbo-macedonian unit (velojić et al. 2018). the deposit is a high and low sulphidation epithermal gold mineralization hosted by andesites and quartz veins (jelenković et al. 2008), which formed during oligocene-miocene magmatism (velojić et al. 2018). ore minerals are galena, sphalerite, pyrite, and gold (jelenković et al. 2008). reserves are 3.4 million tons at 1.8% pb, 3.5% zn, and 3.3 g/t au (jelenković et al. 2008). the tailings of lece (fig. 3 a) cover an area of 23 ha (geological survey of slovenia 2022). 2.4. rudnik the rudnik deposit is a hydrothermal skarn pb-zn deposit hosted by limestones, flysch and quartz latites (jelenković et al. 2008). the deposit is part of the šumadija metallogenetic zone in the vardar zone and was formed by oligocene-miocene magmatism (stojavonić et al. 2006) from fluids of magmatic origin (stojavonić et al. 2018). the main ore minerals are galena, sphalerite, scheelite, chalcopyrite, cassiterite, and bismuthinite (stojavonić et al. 2006). resources are 3.4 mt at a grade of 2% pb, 2% zn, 0.4% cu, and 89 g/t ag (jelenković et al. table 1. country, wgs 84 (epsg: 4326) coordinates, main elements, surface and quantity of material stored in the sampled tailings. all numbers are taken from geological survey of slovenia (2022). location country longitude latitude main elements surface (ha) quantity (mt) lojane n. macedonia 21.66522 42.21793 cr-sb-as 3 0.5 bučim n. macedonia 22.37727 41.67626 cu 250 125 sasa i n. macedonia 22.52203 42.11039 pb-zn 12 5 sasa ii n. macedonia 22.52664 42.10648 pb-zn 12 5 sasa iii n. macedonia 22.53272 42.10320 pb-zn 23 10 probištip i n. macedonia 22.17857 41.99453 pb-zn 24 7 probištip ii n. macedonia 22.18053 41.98681 pb-zn 40 12 probištip iii n. macedonia 22.17795 41.97414 pb-zn 33 11 bor i serbia 22.10574 44.07203 cu 18 8 bor ii serbia 22.11171 44.06685 cu 37 22 krivelj i serbia 22.10699 44.13609 cu 35 65 krivelj ii serbia 22.12033 44.13086 cu 47 95 grot serbia 22.16732 42.56455 pb-zn 26 5.5 lece serbia 21.58800 42.88517 pb-zn 23 2.7 rudnik serbia 20.48978 44.10877 pb-zn-cu 41 8.7 table 2. overview and basic information of the ore deposits from which the evaluated tailings have been produced; srb = serbia, nmk = north macedonia. locality commodity deposit type host rocks reserves (mine) mining reference bor (srb) cu, au, ag high sulphidation porphyry cu intermediary magmatites 14.5 mt active jelenkovic et al., 2008; jelenković et al., 2016 krivelj (srb) cu, au, ag high sulphidation porphyry cu intermediary magmatites 690 mt active jelenkovic et al., 2008; jelenković et al., 2016 grot/blagodat (srb) pb, zn hydrothermal pb-zn granitoids, gneisses, limestones 0.4 mt inactive jelenkovic et al., 2008; djokić et al., 2012 lece (srb) pb, zn, au epithermal gold andesites with quartz veins 3.3 mt active jelenkovic et al., 2008 rudnik (srb) pb, zn, cu, ag skarn limestones, flysch, quartzlatites 3 mt active jelenkovic et al., 2008 sasa (nmk) pb-zn skarn marble, schist 12.6 mt active strmić palinkas et al., 2013 probištip (nmk) pb-zn hydrothermal pb-zn intermediary volcanics 9.8 mt active serafimovski et al., 2006; spasovski & spasovski, 2013; tasev et al., 2018 bučim (nmk) cu, au, ag porphyry cu intermediary plutonites in gneisses 34 mt active serafimovski et al., 1996 lojane (nmk) as, sb, cr veins at contact of rhyolite and podiform chromite rhyolite and podiform chromite 0.3 mt inactive cassard et al., 2008; tasev et al., 2017; kolitsch et al., 2018 g eo lo gi a c ro at ic a geologia croatica 75/special issue 294 (strimić palinkas et al. 2013). the tailings of sasa (fig. 3 c) cover an area of 47 ha (geological survey of slovenia 2022). 2.6. probištip the probištip tailings dam comprises tailings of the zletovo subvolcanic hydrothermal pb-zn deposit related to cenozoic volcanism (serafimovski et al. 2006). the deposit has been mined from medieval times until recently (spasovski & spasovski 2013). an apparently long ongoing problem is acid mine drainage as the river into which the mine dewaters (spasovski & spasovski 2013) is called kiselnica, which can be literally translated to “acid”. it is unknown, if this name refers to natural 2008). the tailings of rudnik (fig. 3 b) cover an area of 41 ha (geological survey of slovenia 2022). 2.5. sasa the sasa pb-zn deposit is classified as epigenetic-hydrothermal skarn mineralization related to oligocene magmatism (tufar & štrucl 1984; strimić palinkas et al. 2013). hence the described minerals are typical skarn minerals: calc-silicates (pyroxenes, garnets, ilvaite, epidote), magnetite, pyrite, and pyrrhotite, but there are also open-space filling hydrothermal minerals such as galena, sphalerite, pyrite, and minor chalcopyrite with abundant quartz and carbonates (strimić palinkas et al. 2013). the reserves are 12.6 million tons at 7.5 % lead and zinc figure 2. field images of a, b the bor tailings; c the krivelj tailings; d the grot tailings. figure 3. field images of a the lece tailings; b the rudnik tailings; c the sasa tailings; d the probištip tailings. g eologia c roatica steiner et al.: preliminary chemical and mineralogical characterization of tailings from base metal sulfide deposits in serbia and north macedonia 295 acid drainage from the deposit, or acid mine drainage from the medieval mines. the main ore minerals are galena, sphalerite, pyrite, chalcopyrite, and siderite (serafimovski et al. 2006). the tailings dam (fig. 3 d) covers an area of 97 ha (geological survey of slovenia 2022) and hosts 4 million tons at an average thickness of 9.2 m and holds a metal content of 0.37 % pb and 0.32 % zn (spasovski & spasovski 2013). 2.7. bučim the bučim deposit is a small porphyry cu deposit hosted by latites and andesites intruded into gneisses during the oligocene (serafimovski et al. 1996). the deposit is part of the lecechalkidiki metallogenic zone. the main ore minerals are chalcopyrite, pyrite, magnetite, haematite, cubanite, valleriite, native gold, and bornite with chalcopyrite dominating (serafimovski et al. 1996). the deposit is still in production and reserves are 34 million tons at 0.267 % cu (cassard et al. 2015). additional precious metals are au (0.35 g/t), and ag (1 g/t) (serafimovski et al. 1996). the tailings of bučim (fig. 4 a) cover an area of 250 ha (geological survey of slovenia 2022). 2.8. lojane lojane is a former as, sb, and cr mine in northern macedonia, which was in operation from 1923-1979 (tasev et al. 2017). veins formed at the contact of rhyolite and podiform chromite bearing ophiolite (kolitsch et al. 2018). the main ore minerals are chromite and as and sb phases: orpiment, realgar, and stibnite; additional phases include bravoite, vaesite, cattierite, pyrite, marcasite, molybdenite, and pitchblende (tasev et al. 2017). see kolitsch et al. (2018) for an exhaustive list of primary and secondary minerals. the reserves in the mine are estimated at 0.3 million tons (cassard et al. 2015). the completely unprotected tailings hold 3.5 million tons of which 15 000 tons are 50 % as concentrate (tasev et al. 2017). currently, the acid mine drainage potential is low, but the waste material is distributed by wind, surface water and groundwater (uiblein 2021). the tailings of lojane (fig. 4 b) cover an area of 3 ha (geological survey of slovenia 2022). 3. methods the 10 kg samples were collected by the geological survey of slovenia from flotation tailings, which were already affected by remnants of vegetation. representative samples were obtained by taking composite samples from the surface, trenches, and handdrilled holes. at the facilities of the geological survey of slovenia, the samples were dried at 40 °c, crushed and homogenized. the resulting fine sand-size material was embedded in resin and polished for examination by reflected light microscopy and scanning-electron microscopy (sem-edx) employing a zeiss evo ma 10 with bruker energy-dispersive analysis system. additionally, for sample pr01a from probištip, a heavy mineral concentrate was produced by sieving the sample to a grain size between 60 µm and 500 µm, and separation with bromoform (density of 2.89 g/cm³). after washing and drying, the sample was embedded in resin and polished for examination by sem-edx. subsequently, sphalerite identified in sample pr01a was examined by laser ablation inductively coupled plasma mass spectrometry (la-icp-ms), utilizing an esi nd:yag laser ablation system coupled to a perkinelmer nexion 2000 icp-ms. la-icp-ms analyses were carried out at the department of applied geosciences and geophysics, montanuniversität leoben in austria. helium was used as carrier gas (flow rate of 0.75 l/min) and mixed with ar during transport into the icp-ms. a spot size of 50 μm was used for all analyses with an on-mineral fluency of 2-3 j/cm2. individual spot analyses are composed of 30s background collection (pre-ablation) followed by 60s of ablation and data collection. thirty seconds of washout followed each laser ablation cycle. twenty-nine isotopes were measured for each spot analysis: 34s, 51v, 52cr, 55mn, 57fe, 59co, 60ni, 63cu, 65cu, 66zn, 67zn, 71ga, 72ge, 74ge, 75as, 82se, 95mo, 107ag, 111cd, 115in, 118sn, 121sb, 125te, 197au, 201hg, 202hg, 205tl, 208pb and 209bi. trace element quantification was done with the in-house sphalerite matrix-matched sinter pressed powder pellet reference material mul-zns1 (onuk et al. 2017) using 34s as the internal standard. the mul-zns1 is not suitable for quantification of au, tl and hg, thus the usgs polysulfide mass-1 (wilson et al. 2002) was used for these elements. to ensure the quality of the analyses, the mass-1 was used for quality control. the iolite 4 software (paton et al. 2011) was utilized for data reduction of the measured count signals into concentrations and detection limits. detection limits were calculated using the ‘howell et al. 2010’ method found in the iolite 4 software. instrumental drift correction was done by repeatedly measuring the reference materials. time-resolved count signals of the different isotopes were scrutinized during data reduction to identify possible inclusions within the ablated sphalerite. major and trace elements of all samples were analyzed by a commercial laboratory (activation laboratories, canada) using the packages 4b-inaa(litho), 4b1, 4f-c, s, 4f-co2, 4litho (1-10). 4. results all samples showed traces of organic material (mainly plant roots) and signs of advanced weathering (mostly reddish colours and the typical smell of weathered sulfides) and have a grain size figure 4. field images of a the bučim tailings; b the lojane tailings. g eo lo gi a c ro at ic a geologia croatica 75/special issue 296 in the silt to fine-sand range (0.002 mm to 0.2 mm). many grains had weathered rims and showed fractures probably related to processing. the weathered rusty iron-rich rims are indicated as feox as the determination of the water/oh content is not possible using sem analysis and a full characterization of those phases was not relevant for this study. table 3 presents the minerals identified by sem in each sample. mineral abundances were estimated qualitatively based on the sem analyses. rare minerals were identified a few times (less than 10) per sample and accessory minerals were only identified once or twice per sample. mineral formulae of uncommon minerals are given in the appendix. in all cases except for grot/blagodat and lojane, the samples were dominated by large silicate grains, mainly quartz and feldspars. in the case of grot/blagodat, the sample was dominated by large grains of quartz and pyrite. the sample from lojane was dominated by iron oxides, olivine, quartz, and realgar. in figs. 5 7, representative mineral associations of the tailings samples are illustrated using back-scattered electron images (bse). 4.1. bor and krivelj the samples from bor and krivelj (fig. 5a, b) show a bimodal grain size distribution and mainly comprise large silicate grains of quartz, plagioclase, and orthoclase in the 100 µm to 300 µm range. in the smaller size class of <5 µm to 50 µm, biotite, iron oxides, pyrite, kaolinite, and rutile are abundant in the bor tailings. in the krivelj tailings, biotite, feox, pyrite, chalcopyrite, galena, chlorite, rutile, and ilmenite prevail. rare minerals in the bor tailings are chalcopyrite, baryte, and titanomagnetite with alunite, colusite, and enargite as accessories. rare minerals in the krivelj tailings are baryte, apatite, allanite, haematite, magnetite, phlogopite, xenotime, and zircon. in the bor tailings, the sulfides are mostly intergrown with quartz. in the krivelj tailing, part of the sulfides occur as free grains. in both tailings, the sulfides have a grain size of 1 µm to 50 µm. 4.2. grot/blagodat the sample from grot (fig. 5c) shows a polymodal size distribution with 100 µm to 300 µm, 25 µm to 50 µm, and < 10 µm size classes. the two larger size classes are dominated by quartz and pyrite, which forms liberated grains of up to 50 µm and also occurs as inclusions in quartz. abundant minerals in the two smaller size classes are biotite, feox, calcite, siderite, rutile, and jacobsite. rare minerals are baryte, apatite, allanite, haematite, magnetite, phlogopite, xenotime, and zircon. the sulfides reach a grain size of 10 µm to 30 µm and may be present as liberated grains and as inclusions in quartz. 4.3. lece the sample from lece (fig. 5d) shows a bimodal grain size distribution with the majority (by volume) of grains in the 50 200 µm size range and a fine fraction of < 5 µm. the main minerals are quartz, plagioclase, and orthoclase along with feox as an abundant phase. baryte, galena, sphalerite, kaolinite, rutile, titanomagnetite, and zircon are rare minerals. haematite, fe-sulfates, and tetrahedrite-(zn) are present as accessories. the sulfides attain a grain size of <5 µm to 30 µm and are mainly present as inclusions in quartz. 4.4. rudnik the sample from rudnik (fig. 6a) shows a bimodal grain size distribution with the majority (by volume) of grains in the 30 µm to 200 µm size range and a fine fraction with a size of ~ 5 µm. table 3. mineral abundances and locking of sulfides by deposit. potential ore minerals are in bold. locality very abundant minerals abundant minerals rare minerals accessories grain size/ grain size sulfides locking of sulfides bor (srb) quartz, plagioclase, orthoclase biotite, feox, pyrite, kaolinite, rutile chalcopyrite, baryte, titanomagnetite alunite, colusite, enargite 0-300 µm/10-50 µm mostly intergrown with quartz krivelj (srb) quartz, plagioclase, orthoclase biotite, feox, pyrite, chalcopyrite, chlorite, rutile, galena, ilmenite baryte, apatite, allanite, hematite, magnetite, phlogopite, xenotime, zircon 1-200 µm/1-50 µm free and intergrown with quartz grot/blagodat (srb) quartz, pyrite biotite, feox, calcite, siderite, rutile, jacobsite plagioclase, orthoclase, chlorite, pyroxene, apatite, sphalerite, hematite, titanite zircon 10-300 µm/10-30 µm free and intergrown with quartz lece (srb) quartz, plagioclase, orthoclase feox baryte, galena, sphalerite, kaolinite, rutile, titanomagnetite, zircon hematite, fe-sulfates, tetrahedrite-(zn) 0-200 µm/0-30 µm inclusions in quartz rudnik (srb) amphibole, quartz andradite, pyroxene, chlorite, feox, orthoclase, titanite galena, ilmenite, pyrrhotite, sphalerite, zircon anglesite 5-200 µm/5-20 µm mostly present as inclusions in silicates sasa (nmk) kaolinite, quartz augite, chlorite, orthopyroxene, clinopyroxene, epidote, andradite garnet, feox, galena, mn-calcite, muscovite, orthoclase, pyrite apatite, pyrrhotite, rutile, siderite, sphalerite monazite, rhodonite, zircon 5-200 µm/5-200 µm free and intergrown with silicates probištip (nmk) epidote, quartz baryte, calcite, chlorite, mn-calcite, feox, galena, orthoclase, plagioclase, pyrite, rhodochrosite, mn-siderite albite, phlogopite, pyrrhotite, rutile, sphalerite chalcopyrite, magnetite, manganosite 10-300 µm/10-100 µm pyrite is mostly free and hosts inclusions of the other sulfides bučim (nmk) feox, orthoclase, plagioclase, quartz biotite, phlogopite, pyrite, titanite apatite, chalcopyrite, epidote, ilmenite, pyrrhotite, rutile, zircon molybdenite, xenotime 5-200 µm/5-200 µm free and intergrown with silicates lojane (nmk) feox, olivine, quartz, realgar albite, ankerite, dimorphite, dolomite, magnesite, orthoclase, plagioclase, pyrite, siderite angelellite, cervantite, chromite, enstatite, muscovite, phlogopite, stibnite, wakabayashilite 5-200 µm/5-200 µm mostly free g eologia c roatica steiner et al.: preliminary chemical and mineralogical characterization of tailings from base metal sulfide deposits in serbia and north macedonia 297 the main minerals are amphibole and quartz. abundant minerals are andradite, pyroxene, chlorite, feox, orthoclase, and titanite. rare minerals are galena, ilmenite, pyrrhotite, sphalerite, and zircon. the sulfides have a grain size of 5 µm to 30 µm and are mainly present as inclusions in quartz. 4.5. sasa the sample from sasa (fig. 6b) shows a bimodal grain size distribution with the majority of grains in the 30 200 µm size range and a fine fraction with a size of ~ 5 µm. the main minerals are kaolinite and quartz. abundant minerals are chlorite, orthopyfigure 5. overview bse images of tailings samples. a bor; b krivelj; c grot; d lece. abbreviations: aug = augite, ba = baryte, bt = biotite, cal = calcite, feox = iron oxides, ga = galena, kfs = k-feldspar, px = pyroxene, py = pyrite, qz = quartz, rt = rutile, s = sulfate, sid = siderite. the scale bar has a length of 100 µm. figure 6. a – overview bse image of the sample from rudnik; detail bse images of the samples from; b sasa; c, d probištip. abbreviations: bt = biotite, cal = calcite, chl = chlorite, ep = epidote, feox = iron oxides, ga = galena, kfs = k-feldspar, or = orthoclase, phl = phlogopite, pl = plagioclase, py = pyrite, qz = quartz, rds = rhodosite, rt = rutile, sp = sphalerite, x = xenotime. the scale bar has a length of 100 µm. g eo lo gi a c ro at ic a geologia croatica 75/special issue 298 roxene, clinopyroxene (e.g., augite), orthoclase, muscovite, epidote, feox, galena, andradite garnet, mn-calcite, and pyrite. rare minerals are apatite, rutile, siderite, pyrrhotite, and sphalerite. accessories are monazite, rhodonite, and zircon. the grain size of sulfides that are either liberated or intergrown with silicates, ranges from 5 µm to 200 µm. 4.6. probištip the grain size of the sample from probištip (fig. 6c, d) ranges from 10 300 µm. the main minerals are epidote and quartz. abundant minerals are baryte, calcite, mn-calcite, rhodochrosite, mn-siderite, feox, galena, pyrite, chlorite, orthoclase, and plagioclase. rare minerals include albite, phlogopite, rutile, pyrrhotite, and sphalerite. accessories are chalcopyrite, magnetite, and manganosite. pyrite forms mostly free grains and may host sulfide inclusions. 4.7. bučim the sample from bučim (fig. 7a) shows a bimodal grain size distribution with 50 200 µm and < 5 µm size classes. the main minerals are feox, orthoclase, plagioclase, and quartz. abundant minerals are biotite, phlogopite, pyrite, and titanite. rare minerals are apatite, chalcopyrite, epidote, ilmenite, pyrrhotite, rutile, and zircon. accessories are molybdenite and xenotime. the sulfides have grain sizes from 5 200 µm and occur either as liberated grains or intergrown with silicates. 4.8. lojane the sample from lojane (fig. 7b) shows a bimodal size distribution with 50 200 µm and 5 20 µm size classes. the main minerals are feox, olivine, quartz, orpiment and realgar. abundant minerals are albite, ankerite, dimorphite, dolomite, magnesite, orthoclase, plagioclase, pyrite, and siderite. rare minerals are angelellite, cervantite, chromite, enstatite, muscovite, phlogopite, stibnite, and wakabayashilite. the sulfides are mostly free and present in all size classes. 5. bulk chemical analyses table 4 presents the analytical whole-rock data of the samples. in the following, the measured concentrations of the major commodity metals cu, zn, pb, ag and au are briefly described, along with the levels of critical metals to the eu (co, ga, ge, in, sb) (løvik et al. 2018) and potentially toxic trace elements (as, cd, tl). the bor and krivelj tailings show expected similarities as they originate from the same deposit. however, the sample from krivelj shows a higher amount of cu (560 ppm), whereas s concentrations are higher in the bor sample, indicating a higher proportion of pyrite. based on the sem analyses, cu is mainly hosted by chalcopyrite. concentrations of au are higher in bor (0.3 ppm) than in krivelj (0.04 ppm). compared to more massive cu-zn-pb sulfide ores, the concentrations of critical metals are generally low with 3 ppm co, 15 ppm ga, 2 ppm ge, 0.4 ppm sb, < 0.2 ppm in for krivelj, with the values for bor even being slightly lower. the grot/blagodat tailings contain pb (3870 ppm) and zn (2980 ppm), cu (96 ppm) and ree (60 ppm ce). lead and zn are hosted by galena and sphalerite, respectively. cu bearing minerals were not observed. critical element concentrations are low, but potentially toxic elements are slightly elevated (101 ppm as, 16 ppm cd, 7 ppm tl). the concentrations of au (0.08 ppm) and ag (<1 ppm) are too low to regard these elements as potential bonuses for a case for reprocessing. the lece tailings contain 455 ppm zn, 1680 ppm pb, 0.5 ppm au, but also 722 ppm as and 9.3 ppm tl. zinc is present in sphalerite, pb in galena, and ba (600 ppm) in baryte. no as-bearing minerals were discovered by sem analysis, suggesting that as is hosted by fe oxide or other secondary phases. the low s concentrations (0.2%) indicate that pyrite is only of very minor importance. among the critical metals, only sb is of importance, showing concentrations of 75 ppm. the rudnik tailings contain 160 ppm cr, 230 ppm cu, 540 ppm zn, and 1710 ppm pb. no cr or cu bearing minerals were found, but as serpentinites are present in the deposit (stojavonić et al. 2018), such cr contents can be expected. it remains unclear though, which mineral phase hosts the cr (probably chromite or cr-bearing chlorite). zinc is hosted by sphalerite; pb is mainly hosted by galena, and additionally by anglesite. precious metal concentrations are low (5.7 ppm ag, <2 ppb au), as well as high-tech metals. among the potentially toxic elements, as has a concentration of 67 ppm, whereas cd and tl are below 1 ppm. the rudnik sample carries the highest concentration of bi (11 ppm) analyzed in this study. the sasa tailings contain 4540 ppm pb, 1900 zn ppm, 90 ppb au, 240 ppm cu, and 520 ppm ba. zinc is present as sphalerite, pb as galena, and ce (54 ppm) mainly in monazite. from the literature (strimić palinkas et al. 2013) it can be expected that cu is present in chalcopyrite and ba in baryte. among the high-tech metals, ge attains the highest value recorded in this figure 7. overview bse images of: a the sample from bučim; b the sample from lojane. abbreviations: bt = biotite, do = dolomite feox = iron oxides, kfs = kfeldspar, ol = olivine, pyr = pyrrhotite, qz = quartz, re = realgar, rt = rutile, sti = stibnite, x = xenotime. the scale bar has a length of 100 µm. g eologia c roatica steiner et al.: preliminary chemical and mineralogical characterization of tailings from base metal sulfide deposits in serbia and north macedonia 299 table 4. chemical analysis data. dl = detection limit; methods: fus-icp = lithium borate fusion and icp-ms/oes analysis; grav = gravimetric; inaa = instrumental neutron activation analysis; td-icp = total digestion icp-oes; co2 = infrared spectroscopy. analyte unit dl method bor krivelj grot/ blagodat lece rudnik sasa probištip bučim lojane sio2 % 0.01 fus-icp 65.65 62.73 52.83 82.16 37.25 45.72 56.79 64.45 35.57 al2o3 % 0.01 fus-icp 12.1 14.74 9.47 6.77 7.86 8.03 8.31 13.61 3.29 fe2o3(t) % 0.01 fus-icp 2.7 5.5 11.36 3.41 18.12 16.22 13.45 6.35 4.79 mno % 0.001 fus-icp 0.005 0.029 1.379 0.015 0.287 1.265 3.918 0.087 0.073 mgo % 0.01 fus-icp 0.04 1.66 2.01 0.05 2.1 1.92 0.29 2.28 4.81 cao % 0.01 fus-icp 0.56 3.22 9.35 0.05 15.77 10.96 0.94 2.45 5.32 na2o % 0.01 fus-icp 0.78 2.66 0.71 0.19 0.26 0.19 0.06 2.83 0.22 k2o % 0.01 fus-icp 1.06 1.73 1.91 3.65 0.63 1.1 1.99 4.54 0.7 tio2 % 0.001 fus-icp 0.485 0.468 0.844 0.242 0.382 0.51 0.376 0.669 0.281 p2o5 % 0.01 fus-icp 0.11 0.14 0.34 0.08 0.08 0.39 0.14 0.25 0.03 loi % grav 16.74 7.64 7.45 2.57 11.9 11.62 10.86 2.88 30.27 total % 0.01 fus-icp 100.2 100.5 97.66 99.2 94.62 97.91 97.13 100.4 85.35 co2 % 0.01 co2 0.03 0.06 5.86 < 0.01 0.13 1.15 4.09 0.89 8.25 au ppb 2 inaa 351 39 77 508 < 2 90 77 88 < 2 ag ppm 0.3 td-icp 1.1 < 0.3 1 2.3 5.7 5.1 17 < 0.3 < 0.3 as ppm 0.5 inaa 22.5 4.8 101 690 66.6 301 306 47.7 > 10000 ba ppm 2 fus-icp 897 275 531 595 103 522 6070 723 340 be ppm 1 fus-icp < 1 2 3 1 2 4 2 3 2 bi ppm 0.4 fus-ms 0.4 < 0.4 < 0.4 < 0.4 11.3 3.3 2.7 1.3 < 0.4 br ppm 0.5 inaa 2.3 2.3 5 4 2.8 1.3 3.2 2.5 < 0.5 cd ppm 0.5 td-icp < 0.5 < 0.5 16.3 < 0.5 0.9 15.9 18.2 < 0.5 < 0.5 ce ppm 0.1 fus-ms 10.3 21.1 59.9 15.1 36.9 54.1 42.9 74.1 14.5 co ppm 1 fus-ms 2 3 17 2 11 13 8 16 60 cr ppm 5 inaa 12 21 73 34 151 54 24 44 1710 cs ppm 0.5 fus-ms < 0.5 0.5 8.1 6.4 6 3.8 13.1 2.3 17.3 cu ppm 1 td-icp 177 562 96 47 226 240 302 361 27 dy ppm 0.1 fus-ms 0.2 1.6 4.1 0.8 2.7 3.7 4.6 4.7 1.9 er ppm 0.1 fus-ms 0.2 1 2.1 0.5 1.5 2 2.9 2.6 1.1 eu ppm 0.05 fus-ms 0.15 0.53 1.52 0.34 0.78 1.11 1.34 1.27 0.4 ga ppm 1 fus-ms 10 15 17 9 14 17 17 19 5 gd ppm 0.1 fus-ms 0.3 1.5 4.8 0.8 3 4.1 4.1 5.3 1.8 ge ppm 1 fus-ms 3 2 3 2 3 5 2 2 3 hf ppm 0.2 fus-ms 1.4 2.3 3.9 1.6 2.3 2.9 3.7 5.4 1.6 ho ppm 0.1 fus-ms < 0.1 0.3 0.7 0.2 0.5 0.7 0.9 0.9 0.4 in ppm 0.2 fus-ms < 0.2 < 0.2 < 0.2 < 0.2 0.3 1.4 9.1 < 0.2 < 0.2 ir ppb 5 inaa < 5 < 5 < 5 < 5 < 5 < 5 < 5 < 5 < 5 la ppm 0.1 fus-ms 5.5 10.3 29.3 9.3 20.9 27.6 22.8 44.2 7.3 lu ppm 0.01 fus-ms 0.06 0.19 0.3 0.09 0.24 0.32 0.43 0.42 0.17 mo ppm 2 fus-ms 2 16 4 < 2 < 2 4 7 11 79 nb ppm 1 fus-ms 3 4 20 3 7 13 7 10 5 nd ppm 0.1 fus-ms 3.6 9.9 27.5 5.8 17.9 24.1 18.8 30 7.5 ni ppm 1 td-icp 1 4 62 4 63 40 13 28 1090 pb ppm 5 fus-ms 51 8 2710 1420 1710 3560 4640 39 89 pr ppm 0.05 fus-ms 1.07 2.49 6.82 1.63 4.61 6.31 4.89 8.15 1.79 rb ppm 2 fus-ms 2 31 126 132 50 71 111 124 42 s % 0.001 td-icp 5.88 1.18 3.07 0.238 4.5 5.85 2.67 0.658 8.26 sb ppm 0.2 inaa 1.2 0.4 3.6 75.4 13.8 5.5 23.6 9.5 > 10000 sc ppm 0.1 inaa 7.4 9.9 9.3 4.6 9.2 8.8 9.8 12.5 10.5 se ppm 3 inaa < 3 < 3 < 3 < 3 < 3 < 3 < 3 < 3 < 3 sm ppm 0.1 fus-ms 0.4 1.8 5.6 1 3.4 4.7 4.1 6.1 1.7 sn ppm 1 fus-ms 3 1 2 1 18 24 3 5 1 sr ppm 2 fus-icp 1205 553 253 138 379 173 304 319 80 ta ppm 0.1 fus-ms 0.2 0.3 1.4 0.3 0.6 0.9 0.7 1 0.4 tb ppm 0.1 fus-ms < 0.1 0.3 0.8 0.1 0.5 0.7 0.8 0.9 0.3 th ppm 0.1 fus-ms 1.4 2.8 5.5 4 5.9 6.5 12.9 21 2.5 tl ppm 0.1 fus-ms 0.3 1.6 7.3 9.3 0.5 3.4 8.5 3.3 38.6 tm ppm 0.05 fus-ms < 0.05 0.16 0.28 0.08 0.21 0.29 0.43 0.35 0.16 u ppm 0.1 fus-ms 0.5 1 3.1 1.7 1.5 3.8 10.2 8.1 19.6 v ppm 5 fus-icp 119 139 104 53 81 134 89 135 48 w ppm 1 fus-ms 4 < 1 25 10 18 29 4 6 45 y ppm 1 fus-icp 2 8 20 4 14 20 26 24 10 yb ppm 0.1 fus-ms 0.3 1.1 1.9 0.6 1.4 1.9 2.9 2.5 1.1 zn ppm 1 td-icp 4 20 2980 455 509 1660 4020 35 50 zr ppm 2 fus-icp 49 82 145 63 79 102 131 190 55 σree ppm 31.5 70.2 174.9 44.9 117.4 160.4 147.7 218.0 60.6 g eo lo gi a c ro at ic a geologia croatica 75/special issue 300 study (5 ppm). it is most likely substituted into the sphalerite structure, along with low concentrations of in (1.4 ppm). toxic element concentrations are moderate (300 ppm as, 16 ppm cd, 3.4 ppm tl). both the rudnik and sasa tailings contain elevated sn (18 and 24 ppm, respectively). the probištip tailings have considerable concentrations of pb (>5000 ppm) and zn (4020 ppm) with some cu (300 ppm). copper is hosted by chalcopyrite, pb by galena (especially its alteration product cerussite), and zn is hosted by sphalerite. silver concentrations (17 ppm) are the highest reported from the selection of samples analyzed in this study. as shown later, ag is partly hosted by sphalerite. the probištip sample carries moderate as (306 ppm), cd (18 ppm) and tl (8.5 ppm), and low concentrations of high-tech metals except for in (9.1 ppm) which reaches the maximum concentration in the sample set studied. the bučim tailings contain some cu (360 ppm) and ba (723 ppm). cu is hosted by chalcopyrite and ba is likely to be hosted by baryte. weak au concentrations (0.09 ppm) do not increase the economic value of the material. concentrations of toxic elements are low (<50 ppm as), as are those of the high-tech metals. the lojane tailings contain very high amounts of as (>2000 ppm) and sb (>10000 ppm), as well as cr (1710 ppm). arsenic is primarily hosted by realgar, and antimony by stibnite, but both are also present in numerous sulfides, arsenates and oxides. cr is hosted by chromite and ni (1090 ppm) is likely hosted by bravoite and vaesite. the analyzed sample reveals 8.3 % s, 60 ppm co, 79 ppm mo, and 45 ppm w. copper is low (30 ppm), and further high-tech elements (ga, ge, in) are close to or below detection limit. the lojane tailings differ from all the above as they do not provide any options to recover cu, pb, au and ag. the potential is clearly dominated by sb and as with minor ni and co. 6. sphalerite trace element data chemical analysis of the tailings sample from probištip indicated elevated concentrations of combined zn and pb, at 2.7 % s. the polished section contained a variety of ore minerals, including galena, sphalerite and chalcopyrite. sphalerite is often an important host of minor and trace elements. therefore, it was decided to perform preliminary trace element analyses on sphalerite using la-icp-ms. data presented in table 5 indicate low median concentrations of fe (0.47%), with some higher concentrations reaching 6.8%, and moderate cd (0.41%) reaching more than 1% in cases. element spectra over the time of analysis in the majority of cases do not show significant spikes that would point to invisible inclusions. in most sphalerite particles, cu contents are elevated, most probably due to fine exsolution of and intergrowth with chalcopyrite. the median contents of typical by-product elements in sphalerite are 3.7 ppm ge, 2.5 ppm ga and 7.4 ppm in. compared with the large dataset of cook et al. (2009) of trace elements in sphalerites, ga and ge are in the expected range, while in is clearly below the median. the median content of ag is 13 ppm but ranges up to 700 ppm in single particles. 7. discussion and conclusions besides mineralogical and chemical differences, the analyzed tailings from nine sites in southeastern europe have some features in common: first, their predominant grain-size is in the sand-silt range (0.002 mm to 0.5 mm), many show a bimodal size distribution and, their composition is quite variable as expected from the literature. the first point is positive in the context of the possible recovery of the metals since mining fine-grained material needs little specialized equipment, and even the processing is more energy/cost-efficient as most of the necessary preparation steps as crushing or milling have been done previously during former operations. however, as shown in table 3, most of the sulfides have a small grain size compared to the gangue minerals and are often intergrown with or present as inclusions in the latter, respectively. there are several possible explanations for the bimodal size distribution. for tailings of flotation plants, a fairly uniform grain size should be expected; this would be the larger size class observed. the smaller size class in the range of < 10 µm could represent dust that was not removed prior to flotation, abrasion prodtable 5. statistical results of la-icp-ms analysis on sphalerite particles (n = 25) from the probištip tailings. element contents in ppm. isotope median min max 55mn 95 <11 1167 57fe 4696 531 67696 59co <1.4 <1.4 54 60ni <4 <4 <4 63cu 459 11 2903 71ga 2.5 <1.1 494 74ge 3.7 <3 25 75as 19 <5 1815 95mo <1.2 <1.2 <1.2 107ag 13 <0.6 701 111cd 4153 1359 11183 115in 7.4 <0.2 443 118sn 2.4 <2 59 121sb 16 <0.5 2188 202hg 44 22 465 205tl <0.2 <0.2 46 208pb 21 <0.3 15334 209bi <0.2 <0.2 <0.2 table 6. summary of potentially valuable elements and element carrier minerals in the tailings samples. locality major commodity metals precious metals eu-critical metals toxic metals main metal-bearing minerals for recovery bor (srb) cu au pyrite, chalcopyrite, colusite, enargite krivelj (srb) cu (au) pyrite, chalcopyrite, galena grot/blagodat (srb) pb, zn (au) as, cd, tl pyrite, sphalerite lece (srb) pb, zn au sb as, tl fe oxides(?), baryte, galena, sphalerite, tetrahedrite rudnik (srb) pb, zn (cu) ag (as) galena, pyrrhotite, sphalerite, anglesite sasa (nmk) pb, zn (cu) au ge (in) as galena, pyrrhotite, sphalerite probištip (nmk) pb, zn, cu ag in as galena, pyrrhotite, sphalerite, chalcopyrite bučim (nmk) (cu) chalcopyrite, molybdenite lojane (nmk) sb, cr, ni sb, co as realgar, orpiment, stibnite and other sb-as phases g eologia c roatica steiner et al.: preliminary chemical and mineralogical characterization of tailings from base metal sulfide deposits in serbia and north macedonia 301 ucts originating from the flotation and subsequent processes, dust that was removed before flotation but mixed before or during dumping in the tailings dam, or in situ formed weathering products including clay minerals. as a final possibility, analytical bias may have been introduced during crushing, sample preparation, or an unfavourable cutting plane of the polished section could be responsible for the observed bimodal size distribution. as most samples with a bimodal size distribution show a different mineralogy in the various size classes, an unfavourable cutting plane or an effect of crushing is unlikely. given the attempts to gather and prepare representative samples during all steps from sampling to preparation, it can be assumed, that the bimodal size distribution is really present in the sampled tailings. the high spatial variability poses problems for mining and processing, some of which may be tackled using geophysical methods to investigate the shape of the tailings bodies which in some cases were just dumped to fill valleys. more problems are likely to be caused by the chemical variability, even at the sample scale, as the tailings are far from homogeneous. all the available reports on these tailings draw attention to their enormous inhomogeneity (kolitsch et al. 2018). in an extreme case, for the lojane tailings, there are even reports of “numerous heaps of black and white powder” consisting of stibnite concentrate and arsenolite (as2o3) thought to be remnants of 2500 wooden barrels stored at the smelter (tasev et al. 2017). at the same place a tailings pile and a concentrate storage pond are reported, the latter holding approximately 15 000 tons of 50 % as concentrate (tasev et al. 2017). from an economic point of view, the metal contents analyzed in the tailings samples do not indicate a high potential for mining because they are comparatively low. however, given the easy access and likely low mining costs, some of the tailings may become economic if metal prices increase due to foreseen future shortages for base and critical high-tech metals. in any case, a possible and in many cases ecologically worthwhile remediation could at least partly be financed by the recovery of some valuable metals. in table 6, we provide a summary of the potential identified using whole-rock chemical and in-situ mineralogical and mineral chemical analyses. the highest total metal concentrations were found in the sample from the probištip tailings with 0.4% zn, >0.5% ppm pb and 300 ppm cu; however, those grades are still low compared to commercial mines. unfortunately, the sulfide phases such as sphalerite do not carry elevated trace element concentrations that would economically support re-mining and processing the material. the base metal sulfides are often locked in pyrite which is mostly present as free grains. this poses challenges for reprocessing, but it should be kept in mind, that modern processing plants are significantly more powerful in every aspect than in the past. additionally, it should be considered worthwhile to process the lojane tailings dam as this would not only reveal considerable amounts of as and sb, but also protect the local environment from further toxification. increasing metal prices might facilitate feasibility studies for some of the localities in the near future. acknowledgement this contribution is supported by the project “reseerve – mineral potential of the esee region” funded by the european institute of innovation and technology (eit), a body of european union, under the horizon 2020, the eu framework programme for research and innovation. references asch, k. (2005): the 1 : 5 million international geological map of europe and adjacent areas igme 5000. bgr, hannover. cassard, d., bertrand, g., billa, m., serrano, j.-j., tourlière, b., angel, j.-m. & gaál, g. (2015): promine mineral databases: new tools to assess primary and secondary mineral resources in europe.– in: 3d, 4d and predictive modelling of major mineral belts in europe. springer, 9–58. doi: 10.1007/978-3-319-17428-0_2 cassard, d., leistel, j.-m., lips, a.l.w. & stein, g. (2008): metallogenic map of central and southeastern europe: an extract from gis central europe | european minerals knowledge data platform (eu-mkdp). brgm. cook, n.j., ciobanu, c.l., pring, a., skinner, w., shimizu, m., danyushevsky, l., saini-eidukat, b. & melcher, f. (2009): trace and minor elements in sphalerite: a la-icpms study.– geochimica et cosmochimica acta, 73, 4761–4791. doi: 10.1016/j.gca.2009.05.045 djokić, b.v., jović, v., jovanović, m., ćirić, a. & jovanović, d. (2012): geochemical behaviour of some heavy metals of the grot flotation tailing, southeast serbia.– environ. earth. sci., 66, 933–939. doi: 10.1007/s12665-011-1303-6. geological survey of slovenia (2022): west balkan mineral register of secondary raw materials. https://reseerve.eu/results/west-balkan-mineral-registerof-secondary-raw-materials (last accessed on 20.01.2022.) janković, s. (1977): the copper deposits and geotectonic setting of the thethyan eurasian metallogenic belt.– mineralium deposita, 12, 37–47. jelenković, r., kostić, a., životić, d. & ercegovac, m. (2008): mineral resources of serbia.– geologica carpathica, 59, 345–361. jelenković, r., milovanović, d., koželj, d. & banješević, m. (2016): the mineral resources of the bor metallogenic zone: a review.– geologia croatica, 69, 143–155. doi: 10.4154/gc.2016.11 kolitsch, u., djordjevic, t., tasev, g., serafimovski, t., boev, i. & boev, b. (2018): supergene mineralogy of the lojane sb-as-cr deposit, republic of macedonia: tracing the mobilization of toxic metals.– geologica macedonica, 32, 95–117. lottermoser, b. (2010): mine wastes: berlin.– springer, heidelberg, 400 p. doi: 10.1007/978-3-642-12419-8. løvik, a.n., hagelüken, c. & wäger, p. (2018): improving supply security of critical metals: current developments and research in the eu.– sustainable materials and technologies, 15, 9–18. doi: 10.1016/j.susmat.2018.01.003 onuk, p., melcher, f., mertz-kraus, r., gäbler, h.-e. & goldmann, s. (2017): development of a matrix-matched sphalerite reference material (mulzns-1) for calibration of in situ trace element measurements by laser ablation-inductively coupled plasma-mass spectrometry.– geostandards and geoanalytical research, 41, 263–272. doi: 10.1111/ggr.12154 paton, c., hellstrom, j., paul, b., woodhead, j. & hergt, j. (2011): iolite: freeware for the visualisation and processing of mass spectrometric data.– journal of analytical atomic spectrometry, 26, 2508–2518. doi: 10.1039/ c1ja10172b serafimovski, t., cifliganec, v. & boev, b. (1996): genetic model of the buchim porphyry copper deposit, republic of macedonia.– in: proceedings of the annual meeting. university of mining and geology-st.” ivan rilski”, sofia, 63–74. serafimovski, t., dolenec, t. & tasev, g. (2006): new data concerning the major ore minerals and sulphosalts from the pb-zn zletovo mine, macedonia.– rmz-materials and geoenvironment, 52, 535–548. spasovski, o. & spasovski, d. (2013): geochemical characteristics and significance of tailing dump from polymetallic pb-zn deposit zletovo (republic of macedonia).– in: 5th jubilee balkan mining congress. elem macedonia. stojavonić, j., tosovic, r., pačevski, a., radosavljević, s., kašić, v. & vuković, n. (2018): a review of the pb-zn-cu-ag-bi-w polymetallic ore from the rudnik orefield, central serbia.– geoloski anali balkanskog poluostrva, 79. doi: 10.2298/gabp1879047s stojavonić, j.n., radosavljević, s.a., karanović, l. & cvetković, l. (2006:) mineralogy of w–pb–bi ores from rudnik mt., serbia.– neues jahrbuch für mineralogie-abhandlungen: journal of mineralogy and geochemistry, 182, 299–306. stojavonić, j.n., radosavljević, s.a., tošović, r.d., pačevski, a.m., radosavljević-mihajlović, a.s., kašić, v.d. & vuković, n.s. (2018): a review of the pb-zn-cu-ag-bi-w polymetallic ore from the rudnik orefield, central serbia.– geoloski anali balkanskoga poluostrva, 79, 47–69. strimić palinkas, s., tasev, g., serafimovski, t., palinkas, l., šmajgl, d. & peltekovski, z. (2013): ore-fluid evolution at the sasa pbzn skarn deposit, republic of macedonia.– in: ausimm new zealand branch annual conference 2013. australasian institute of mining and metallurgy, 487–494. tasev, g., serafimovski, t., djordjevic, t. & boev, b. (2017): soil and groundwater contamination around the lojane as-sb mine, republic of macedonia.– in: 17th international multidisciplinary scientific geoconference sgem 2017, 17, 809–817. https://doi.org/10.1007/978-3-642-12419-8 g eo lo gi a c ro at ic a geologia croatica 75/special issue 302 tufar, w. & štrucl, i. (1984): the sasa lead-zinc deposit (macedonia/yugoslavia) and its position in the serbian-macedonian ore province.– in: wauschkuhn, a., kluth, c. & zimmermann, r.a. (eds.): syngenesis and epigenesis in the formation of mineral deposits. springer, berlin heidelberg, 412–421. uiblein, s.h. (2021): mineralogy and geochemistry of the major mining waste dump of the former as-sb-cr mine in lojane, north macedonia.– mitteilungen der österreichischen mineralogischen gesellschaft, 167. velojić, m., prelević, d. & jelenković, r. (2018): the origin of lead and sulphur in tulare ore field, lece magmatic complex, se serbia.– geoloski anali balkanskoga poluostrva, 79/2, 19–28. doi: 10.2298/gabp1802019v wilson, s.a., ridley, w.i. & koenig, a.e. (2002): development of sulfide calibration standards for the laser ablation inductively-coupled plasma mass spectrometry technique.– journal of analytical and atomic spectrometry, 17, 406–409. doi: 10.1039/b108787h www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2025 | 78/3 | 243–256 | 7 figs. | 2 tabs. | geozonation of the zagreb city area as an input for seismic risk assessment laszlo podolszki1,*, josip terzić1, matko patekar1 1 croatian geological survey, department of hydrogeology and engineering geology, milana sachsa 2, 10000 zagreb, croatia; (*corresponding author: lpodolszki@hgi-cgs.hr) doi: 10.4154/gc.2025.15 abstract the zagreb city area is located in a geologically diverse and complex area: on the southern slopes of medvednica mountain, the alluvial plains of the sava river, and on the northern slopes of the vukomeričke gorice hilly area. the urbanisation of this relatively large area is an ongoing process, and nowadays, the city’s development is proceeding rapidly in unfavourable locations in terms of geohazards, meaning that areas with a possible seismic, flood, or landslide risk are becoming increasingly populated. to achieve sustainable deve­ lopment, geohazards and ground types need to be addressed and assessed for the whole area of zagreb city as the input for seismic risk assessment. as one step in that direction, existing geological data were reviewed and analysed, and accordingly, geozonation of the zagreb city area was carried out, differentiating four zones with six geological complexes. based on the available geological data, we assessed the geohazard processes, ground types, and seismic risk for each differentiated zone and complex, and in that way, a small­ scale regional zonation map was developed. further detailed geo-research of the zagreb city area is recommended as the city area is relatively large and heterogeneous in terms of geological settings, and detailed geo­data are needed to define local geo­conditions, geohazards, and ground types. with detailed geo-data, the presented geozonation of the zagreb city area could be upscaled and directly applied in urban planning. the presented results were used as input for the seismic risk assessment for the research area, and the developed regional map is already being used by the local government. 1. introduction sustainable development relies on adequate planning (mensah, 2019; sale & el kawy, 2021; yang, 2023), for which reliable and quality data are needed (lamelas et al., 2009; gong et al., 2021; li et al., 2023). from detailed and up-to-date data, usable and practical thematic maps can be developed (podolszki & karlović, 2023; di salvo et al., 2024) and used in geohazard assessment (el aal et al., 2020; bostjančić et al., 2021) and urban planning (hart & hearn, 2018; zhou et al., 2021). geohazards include a variety of phenomena, e.g.: volcanic and seismic activity, mass movements, liquefaction, problematic soils, river and sea control, wind effects, erosion (bell, 2003; cuervas-mons et al., 2022; cemiloglu et al., 2023). zonation and risk assessment studies have been successfully carried out at various temporal and spatial scales to evaluate the vulnerability and susceptibility to a particular geohazard (twisdale & vickery, 1995; rahman et al., 2009; vamvakaris et al., 2016; constantinescu et al., 2022; ali et al., 2023), fostering the development of adequate mitigation strategies (ferreira & lourenço, 2019; chaudhary & piracha, 2021). this paper focuses on reviewing geological data as input for seismic risk assessment as one aspect of geohazard manage ment for the zagreb city area (miklin et al., 2019; podolszki & terzić, 2023). zagreb is the capital of croatia, with an area of ≈ 641 km2 (fig. 1a) and a population of ≈ 770,000 with a population density of ≈ 1,200 persons per km2 (bešlić et al., 2023). its development and urbanisation are an ongoing process (fig. 1b), with the urban sprawl progressing on the southern slopes of medvednica mt., around the sava river, and on the northern slopes of the vukomeričke gorice hilly area (fig. 1c). the existing geozonation for the zagreb city area from 2008 is outdated (fig. 1d, jurak et al., 2008) and should be updated with new data and standards, such as a ground type assessment based on eurocode 8 (en 1998-1:2004, 2005). one of the crucial aspects of risk management for the zagreb city area is the assessment of seismic risk, as the threat is real and present. in particular, two recent earthquakes from 2020 took several human lives (markušić et al., 2020; podolszki et al., 2023b), and caused significant damage (fig. 2). these earthquakes (zagreb, 22nd march 2020, m5.5, fig. 2a–c, and petrinja, december 29th 2020, m6.2, ≈ 45 km southeast of zagreb, fig. 2d, e) were devastating for both zagreb and croatia. in order to increase the resilience and minimise the effects of future disasters in the zagreb city area, the available geological data were reviewed (podolszki & terzić, 2023), and the existing geozonation was updated (jurak et al., 2008), resulting in a new small-scale regional map with four differentiated zones and six geological complexes. based on the available geological data (geological, hydrogeological, and engineering geological maps with article history: manuscript received: november 4, 2024 revised manuscript accepted: july 11, 2025 available online: october 15, 2025 keywords: zagreb city area, geological maps, geozonation, geohazards, ground type, seismic risk assessment, sustainable development mailto:lpodolszki@hgi-cgs.hr g eo lo gi a c ro at ic a 244 geologia croatica 78/3 explanatory notes and different geological, hydrogeological, and engineering geological data available from the literature for the zagreb area), the seismic risk was assessed and the main geohazard process types were defined for each zone and complex along with ground types according to eurocode 8 (miklin et al., 2019; podolszki & terzić, 2023). even though the developed map is a regional-scale map, it represents an important step in seismic risk management. with more detailed geo-data (data from boreholes, laboratory data, geophysical measurements, etc.), the presented geozonation of the zagreb city area could be upscaled and directly applied in urban planning. the brief research results were presented in the form of a technical report in croatian (podolszki & terzić, 2023), but with limited reach and availability. moreover, it is important to present the findings to the academic community and to a wider audience in the form of an open-access document as it helps in seismic risk preparedness and awareness raising. 2. materials and methods earthquakes can be triggered by a variety of factors, but the common characteristic of all earthquakes is that they release different amounts of energy within the earth that is spread by seismic waves (beroza & kanamori, 2015; university of zagreb, 2024). seismic waves spread through heterogeneous geological media: various materials (rocks, sediments, formations) have different physical characteristics, and different types of rocks and soils differ in the energy transfer of seismic waves (zaccagnino & doglioni, 2022; podolszki & terzić, 2023). the energy transfer is also figure 1. research area: a zagreb city area within croatia; b zagreb city area topography; c zagreb city area morphology; d existing geozonation for zagreb city area with defined zones (jurak et al., 2008): i – medvednica mt. area, iia, b, c – slopes of medvednica mt. with wider area, and iiia, b, c – the wider area of the sava river. g eologia c roatica 245podolszki et al.: geozonation of the zagreb city area as an input for seismic risk assessment affected by structural features (e.g., fault systems), the amount of water in sediments, and the physical and mechanical properties of the materials (levchenko, 2006; crane, 2013; dong & luo, 2022; zaccagnino & doglioni, 2022; podolszki & terzić, 2023). geological, hydrogeological, and engineering geological data and maps can give certain insights into these important parameters that affect the behaviour of seismic waves. geological data about medvednica mt. middle triassic basaltic pyroclastic rocks from the ophiolitic mélange is given in slovenec et al. (2024), while chloritoid schist is described by mišur et al. (2023). miocene marls and plio-quaternary sediments of medvednica mt. slope area were investigated by gverić et al. (2024), while the pliocene viviparus beds from vukomeričke gorice are described in kurečić et al. (2021). although various geological materials in the zagreb city area are described within these researches, a comprehensive overview for the whole research area is given within the available “geo” maps and therefore those maps are described in more detail in the following chapters. the available geological, hydrogeological, and engineering geological maps for the zagreb city area were reviewed, and the simplified results are presented herein. although the reviewed maps differ in scale, theme, methodology, and used figure 2. some examples of earthquake damage from 2020 (croatia): a zagreb cathedral – broken tower top; b zagreb main post office; c zagreb old town; d petrinja city – main street area; e petrinja city wider area – collapsed family house. g eo lo gi a c ro at ic a 246 geologia croatica 78/3 standards, the data contained therein are considered representative and reliable. geozonation and differentiation of geological, hydrogeological, and engineering geological complexes were carried out on each respective map through a reinterpretation and review of previously collected data. the results were merged and assembled into a new zonation map for the zagreb city area, presented in chapter 3. 2.1. review of geological maps for zagreb city area basic geological maps contain information about the types of sediments, rocks, and formations present in a certain area (lithological description), their age (stratigraphical description), and structural elements (galván aguilar & chávez, 2012; compton, 2016). furthermore, structural features are usually presented on cross-sections, and basic geological maps provide insights into the bedrock and deeper-seated sediments (varnes, 1974; compton, 2016). the reviewed geological maps of the zagreb city area were at the scales of 1:300,000 and 1:100,000 (fig. 3). a basic geological map of croatia at the scale of 1:300,000 (croatian geological survey, 2009a) with explanatory notes (croatian geological survey, 2009b) gives information about the geological materials present in the area with a lithological, stratigraphical, and tectonic overview. for the zagreb city area, 6 geological complexes (geoc) were differentiated on a 1:300,000 scale map (fig. 3a): the medvednica mt. area (oldest sediments in the area, mostly metamorphic and carbonate rocks, geoc 1), southern slopes of medvednica mt. (mostly miocene clastites and carbonates, geoc 2), northern elevated deposits (mostly quaternary loess, deluvial–proluvial and alluvial sediments consisting of gravels, sands, silts, and clays in different ratios, geoc 3), the sava river area (mostly alluvium, youngest sediments in the area, consisting of gravels, sands, silts, and clays in different ratios, geoc 4), southern elevated deposits (mostly quaternary clastites and loess sediments, consisting of silts and sands with clays, geoc 5), and the northern slopes of the vukomeričke gorice hilly area (mostly neogene clastites, geoc 6). cartographically, the territory of croatia is covered by 74 sheets at a scale of 1:100,000, while 3 sheets at a scale of 1:100,000 cover the zagreb city area: sheet zagreb (šikić et al., 1978) with explanatory notes (šikić et al., 1979), sheet ivanić-grad (basch, 1980a) with explanatory notes (basch, 1980b), and sheet karlovac (unpublished). for the zagreb city area, 5 geological complexes (geoc) were differentiated on a 1:100,000 scale map (fig. 3b): the medvednica mt. area (oldest sediments in the area, mostly metamorphic and carbonate rocks, geoc i), the southern slopes of medvednica mt. (mostly miocene and pliocene clastites and carbonates, geoc ii), northern elevated deposits (mostly neogene and quaternary sediments, consisting of gravels, sands, silts, and clays in different ratios, geoc iii), the sava river area (mostly alluvium, consisting of gravels, sands, silts, and clays in different ratios, geoc iv), and southern elevated deposits on the northern slopes of the vukomeričke gorice hilly area (mainly neogene and quaternary clastites and sediments consisting of gravels, sands, and clays, geoc v). in differentiated geological complexes (fig. 3), the lithology and compactness of the bedrock are different, which greatly affects the energy transfer of the seismic waves. different bedrocks and soil types with varying bedrock depths will cause different levels of ground acceleration as the energy produced by an earthquake is propagated up from the bedrock and through the overlying soil (seville & metcalfe, 2005). peak ground acceleration (pga) values differ as the amplification of seismic waves depends on local geological conditions (bačić & kadiri, 2020). in that sense, welllithified rocks are preferable as the amplification values are lower. in geoc 1 and geoc i, the bedrock is mostly well figure 3. geological maps of zagreb city area with differentiated geological complexes: a original scale 1:300,000 (croatian geological survey, 2009a); b original scale 1:100,000 (basch, 1980a; pikija, 1987; šikić et al., 1978). g eologia c roatica 247podolszki et al.: geozonation of the zagreb city area as an input for seismic risk assessment lithified, which is favourable from the perspective of seismic risk assessment. in geoc 2, geoc 6, geoc ii, and geoc v, the lithification is variable, while in geoc 3, geoc 5, and geoc iii, the bedrock is mostly poorly lithified, which is less favourable from the perspective of seismic risk assessment. the bedrock is mostly non-lithified in geoc 4 and geoc iv, which is unfavourable from the perspective of seismic risk assessment. notably, the differentiated geological complexes in figure 3a, b have different spatial extents due to the different maps of origin and their scales, and the given geological descriptions are simplified. 2.2. review of hydrogeological maps for zagreb city area hydrogeological maps combine geological information with data on the occurrence, movement, and content of groundwater in sediments and rocks, including the aquifer’s hydraulic properties (e.g., hydraulic conductivity, storage), porosity type (e.g., intergranular or fracture), recharge and discharge points, and flow directions (struckmeier & margat, 1995; chaminé et al., 2015). surface water bodies, springs, and wells are also usually marked on these maps with additional information about lithology, stratigraphy, and tectonic elements (struckmeier & margat, 1995; chaminé et al., 2015). since hydrogeological maps give insights into aquifers and surface water bodies, they are generally focused on somewhat shallower seated sediments than basic geological maps (teixeira et al., 2013; chaminé et al., 2015). the reviewed hydrogeological maps of the zagreb city area were at the scales of 1:500,000 and 1:300,000 (fig. 4). a hydrogeological map at a scale of 1:500,000 (ivković & komatina, 1980) with explanatory notes (ivković et al., 1983) gives information about the aquifers present in the area, with a description of their porosity. for the zagreb city area, 6 hydrogeological complexes (hgc) were differentiated on a 1:500,000-scale map (fig. 4a): the medvednica mt. area (area without aquifers, hgc 1), the southern slopes of medvednica mt. (mainly cavernous and fracture porosity aquifers, hgc 2), northern elevated deposits (mainly intergranular-porosity aquifers, but with a relatively low water content, hgc 3), the sava river area (intergranular-porosity aquifers with a relatively high water content, hgc 4), southern elevated deposits (mainly intergranular-porosity aquifers, but with a relatively low water content, hgc 5), and the northern slopes of the vukomeričke gorice hilly area (mainly intergranularporosity aquifers, but with a variable water content, hgc 6). on the hydrogeological map at a scale of 1:300,000 (biondić et al., 2003), the territory of croatia is differentiated according to the aquifer’s properties and lithological types. for the zagreb city area, 6 hydrogeological complexes (hgcs) were differentiated on a 1:300,000-scale map (fig. 4b): the medvednica mt. area (with formations with no or low permeability, hgc i), the southern slopes of medvednica mt. (with formations and sediments with mostly low permeability and transmissivity, hgc ii), northern elevated deposits (with sediments with low to intermediate permeability and transmissivity, hgc iii), the sava river area (with sediments with very high transmissivity, hgc iv), southern elevated deposits (with sediments with mainly low transmissivity, hgc v), and the northern slopes of the vukomeričke gorice hilly area (with formations and sediments with low transmissivity, hgc vi). differentiated hydrogeological complexes (fig. 4) are characterized by a significant variance in the water content as a result of geological (lithology), hydrogeological (presence or absence of aquifers, depth of the groundwater table), and hydrological factors (presence of surface water bodies). the water content greatly affects the energy transfer of seismic waves as, in saturated sediments, the velocity increases (toksöz et al., 1976; levchenko, 2006). in that sense, a figure 4. hydrogeological maps of zagreb city area with differentiated hydrogeological complexes: a original scale 1:500,000 (ivković & komatina, 1980); b original scale 1:1300,000 (biondić et al., 2003). g eo lo gi a c ro at ic a 248 geologia croatica 78/3 lower water content is preferable as the seismic wave velocity values are lower in drier sediments (crane, 2013; kahraman, 2019). complexes hgc 1 and hgc i are characterized by no or very low water contents, which is favourable from the perspective of seismic risk assessment. in hgc 2, hgc 6, hgc ii, and hgc vi, water is present locally but in variable quantities, while in hgc 3, hgc 5, hgc iii, and hgc v, water is present in low quantities, which is less favourable from the perspective of seismic risk assessment compared to complexes hgc 1 and hgc i. in hgc 4 and hgc iv, the water content is mostly high, which is unfavourable from the perspective of seismic risk assessment. notably, the differentiated hydrogeological complexes in figure 4a, b have different spatial extents due to the various maps of origin and their scales, and the given hydrogeological descriptions are simplified. 2.3. review of engineering geological maps for the zagreb city area engineering geological maps provide insights into the physical and mechanical properties of materials, characteristic surface processes, and phenomena for the specific area (geohazards), including information about the lithology, stratigraphy, and tectonics, while the focus is on surface or shallow-seated sediments, soils, and rocks (dearman & fookes, 1974; chacón et al., 2006; price, 2009; corominas et al., 2014). from the engineering geology perspective, the materials are commonly differentiated as rocks or soils (dearman & fookes, 1974). additionally, soft rock or hard soil categories are used for a better description of the materials (dearman & fookes, 1974; price, 2009). the reviewed engineering geological maps of the zagreb city area were at the scales of 1:500,000 and 1:300,000 (fig. 5). an engineering geological map at a scale of 1:500,000 (čubrilović et al., 1967) with explanatory notes (čubrilović, 1969) gives information about the lithology and physical properties of materials, with descriptions of endogenous and exogenous geological processes. on this map, the focus is on slides, falls, erosion, gully forming, and torrent flows. for the zagreb city area, 5 engineering geological complexes (egc) were differentiated on a 1:500,000-scale map (fig. 5a): the medvednica mt. area (area with various lithologies and substantial erosion, where rockfalls are the dominant slope movement, egc 1), the southern slopes of medvednica mt. (an area with mostly sandstones, marls, sands, and clays, prone to erosion and sliding, egc 2), northern elevated deposits (area with mostly gravels, sands, and clays, prone to erosion and sliding, egc 3), the sava river area (with gravels, sands, slits, and clays, where liquefaction can occur due to the high water content in the sandy materials, egc 4), and southern elevated deposits on the northern slopes of the vukomeričke gorice hilly area (mostly lake-type materials with marls, clays, and sands prone to erosion and sliding, egc 5). on the engineering geological map at a scale of 1:300,000 (braun, 2002), the territory of croatia is differentiated according to the engineering geological properties of materials: (i) unconsolidated and weakly consolidated soils (with noncoherent and coherent soils), (ii) sedimentary rocks (clastic and carbonate), and (iii) magmatic rocks (intrusive, effusive, volcanic, pyroclastic, and metamorphic). for the zagreb city area, 6 engineering geological complexes (egcs) were differentiated on a 1:300,000-scale map (fig. 5b), including the assessment of the ground type according to eurocode 8 from the available data: the medvednica mt. area (area with metamorphic, carbonate, and clastic rocks, with the assumed ground type a, egc i), the southern slopes of medvednica mt. (an area with clastic rocks and coherent to non-coherent soil, with the assumed ground types b and c, egc ii), northern elevated deposits (an area with coherent to noncoherent soil, with the assumed ground type c, egc iii), the figure 5. engineering geological maps of the zagreb city area with differentiated geological complexes: a original scale 1:500,000 (čubrilović et al., 1967); b original scale 1:1300,000 (braun, 2002). g eologia c roatica 249podolszki et al.: geozonation of the zagreb city area as an input for seismic risk assessment sava river area (area with non-coherent soil, with the assumed ground types c and d, egc iv), southern elevated deposits (an area with coherent to non-coherent soil, with the assumed ground type c, egc v), and the northern slopes of the vukomeričke gorice hilly area (an area with coherent soil, with the assumed ground types b and c, egc vi). the ground types are detailed below in the next chapter. due to the generally different engineering geological properties of the surface materials in the different egc complexes, the most common geohazard phenomena differ from area to area, the same as for the assumed main ground types according to eurocode 8. the locations of the geohazard phenomena can be affected greatly by earthquakes (bell, 2003; gong et al., 2021; podolszki et al., 2023a), while the ground type greatly affects the energy transfer of seismic waves (bačić & kadiri, 2020; podolszki & terzić, 2023). liquefaction zones or landslide areas can be locations of intensive damage as they can occur or reactivate due to seismic activity (bell, 2003; pollak et al., 2021; podolszki & terzić, 2023). at the same time, seismic wave propagation depends on the locally present ground type (bačić & kadiri, 2020; podolszki & terzić, 2023). according to eurocode 8, the average shear wave velocity in the top 30 m below the surface (vs30) is highest for ground type a (mostly well-lithified bedrocks) and significantly lower for ground types b, c, and d (mostly sediments with variable degrees of lithification). however, the compactness of the materials (penetration number from the standard in situ penetration test, nspt) and their cohesion values (the undrained cohesion value, cu) significantly affect the behaviour of ground types b, c, and d. in that sense, well-lithified rocks are more preferable than poorly lithified or non-lithified sediments. for ground type e, a higher water content can be expected. in ground types s1 and s2, liquefactions or landslides can occur. therefore, ground types e, s1, and s2 are not preferable from the perspective of seismic risk evaluation. in that sense, for egc 1 and egc i, the assumed (main) ground type a is favourable from the perspective of seismic risk assessment. for egc 2, egc 5, egc ii, and egc vi, the assumed (main) ground types b and c are less favourable from the perspective of seismic risk assessment, the same as for the assumed (main) ground type c for egc 3, egc iii, and egc v. for egc 4 and egc iv, the assumed (main) ground types c and d are unfavourable from the perspective of seismic risk assessment. it is worth noting that differentiated engineering geological complexes on figure 5a, b have different spatial extents due to the different maps of origin and their scales, and the given engineering geological descriptions are simplified. 2.4. detailed data reviewed for part of the zagreb city area recent and relevant data for the zagreb city area regarding seismic risk zoning based on geology and the ground type are relatively scarce (miklin et al., 2019; podolszki & terzić, 2023). still, there are valuable studies and data (miklin et al., 2007; herak et al., 2013; miklin et al., 2018; miklin et al., 2019; padovan et al., 2021). for example, detailed data about the engineering geological properties and ground type of sediments (according to eurocode 8) on the southern slopes of medvednica mt. can be found (table 1). the developed and high-detail engineering geological maps provide information about the physical and mechanical properties of materials and about the characteristic surface processes and phenomena for the area (geohazards, with an emphasis on landslides), including information about lithology, stratigraphy, and tectonics, and as such, they should be considered standard for other areas in croatia (miklin et al., 2007; miklin et al., 2018). for the seismic and geological microzonation of part of the zagreb city area, the geological, geotechnical, geophysical, and seismic characteristics of the research area were compiled and addressed (herak et al., 2013; miklin et al., 2019; padovan et al., 2021). groundtype determination and description were performed, and the research results were presented on the developed seismic zonation map in accordance with eurocode 8 at a scale of 1:25,000, where areas of equal soil amplification relative to the table 1. ground types according to eurocode 8 (a-s2) and ground types in the research area (a-d, ≈ 175 km2, ≈ 1/4 of zagreb city area) within zagreb county (herak et al., 2013; miklin et al., 2019; padovan et al., 2021) ground type description vs,30* nspt** cu*** research area (≈ 175 km2) a rock or other rock-like geological formation, including at most 5 m of weaker material at the surface. >800 2.9 km2 1.7% b deposits of very dense sand, gravel, or very stiff clay, at least several tens of metres in thickness, characterized by a gradual increase in mechanical properties with depth. 360 – 800 >50 >250 46.8 km2 26.8% c deep deposits of dense or medium-dense sand, gravel, or stiff clay with thicknesses from several tens to many hundreds of metres. 180 – 360 15 – 50 70 – 250 124.3 km2 71.2% d deposits of loose-to-medium cohesionless soil (with or without some soft cohesive layers) or of predominantly soft-to-firm cohesive soil. <180 <15 <70 0.6 km2 0.3% e a soil profile consisting of a surface alluvium layer with vs values of type c or d and thicknesses varying between about 5 m and 20 m, underlain by stiffer material with vs > 800 m/s. s1 deposits consisting, or containing a layer at least 10 m thick, of soft clays/ silts with a high plasticity index (pi > 40) and high-water content. <100 10 – 20 s2 deposits of liquefiable soils, sensitive clays, or any other soil profile not included in types a – e or s1. * vs,30 is the average shear wave velocity in the top 30 m below the surface ** nspt is the penetration number from the standard in situ penetration test *** cu is the undrained cohesion value g eo lo gi a c ro at ic a 250 geologia croatica 78/3 bedrock were depicted (herak et al., 2013; miklin et al., 2019; padovan et al., 2021). available detailed data for part of the research area (≈ 175 km2, ≈ 27% of zagreb city area) provided insights regarding the types of sediments present in ≈ 1/4 of the zagreb city area (herak et al., 2013; miklin et al., 2019; padovan et al., 2021), including the expected ground types in similar conditions and the sediment types for the rest of the area (≈ 466 km2, ≈ 73% of zagreb city area). still, it must be emphasized that for the rest of the zagreb city area (≈ 3/4), the expected ground type is only an assumption and it should be confirmed through detailed investigations. the available detailed data were used to confirm the assumptions presented in chapter 2.3. for the southern slopes of medvednica mt., and the spatial coverage of the data used is given on the developed map in chapter 3.5. 3. results based on the geological, hydrogeological, and engineering geological zonation performed and the reviewed data for the zagreb city area (presented in chapter 2), a new zonation map was developed, with four differentiated zones of similar features and six geological complexes. the differentiation into six geological complexes was kept to stress that there are some geological and spatial differences between the complexes. the differentiated zones are the mountainous area (zone 1), slopes (zone 2), elevated deposits (zone 3), and an area of alluvial deposits (zone 4). the six differentiated geological complexes are: the medvednica mt. area (within zone 1), the southern slopes of medvednica mt. (within zone 2), elevated deposits – north (within zone 3), the sava river alluvium (within zone 4), elevated deposits – south (within zone 3), and the northern slopes of the vukomeričke gorice hilly area (within zone 2). based on the geo-data used and the analysis performed for each zone and geological complex, a short and simplified description is given with the seismic risk assessment, expected ground type, and characteristic geohazard phenomena. it is worth noting that the six differentiated geological complexes have different degrees of spatial coverage to the initial differentiated geological, hydrogeological, and engineering geological complexes described in chapter 2, due to the available geo-data analysis and engineering judgement used in this research. in the following chapters, a simplified overview of each differentiated zone is provided with a map and a table overview at the end of the chapter. 3.1. zone 1 – mountains zone 1 is a “rocky” area with forests and a protected area of the nature park of medvednica mt. therefore, it is practically non-urban, with a strong emphasis on natural protection. the geological complex of medvednica mt. covers two areas within the zagreb city area (fig. 6; table 2): northwest (≈ 75.2 km2, ≈ 12% of zagreb city area) and northeast (≈ 14.5 km2, ≈ 2% of zagreb city area). zone 1 covers ≈ 90 km2 (≈ 14% of zagreb city area). the main geological feature is that the bedrock is composed of well-lithified rock complexes (šikić et al., 1978; šikić et al., 1979; basch, 1980a, b; pikija, 1987; croatian geological survey, 2009a, b). the main hydrogeological features are that there are practically no aquifers present in the area and the terrain is characterized by no or low permeability (ivković & komatina, 1980; ivković et al., 1983; biondić et al., 2003). the main engineering geological features are that the materials can be characterized as rocks with a relatively shallow weathered zone, which is locally prone to erosion, while falls and torrent flows can occur (čubrilović et al., 1967; čubrilović, 1969; braun, 2002; miklin et al., 2007; herak et al., 2013; miklin et al., 2018; padovan et al., 2021). the weathered zone on the bedrock is relatively thin, the water flow is often surface flow, and the expected ground type for this zone is a (according to eurocode 8, fig. 6; table 2). therefore, from the perspective of seismic risk assessment, this zone has favourable geological, hydrogeological, and engineering geological characteristics (table 2). 3.2. zone 2 – slopes zone 2 comprises the southern slopes of medvednica mt., which is generally a hilly urbanized area with a long history of landslide problems, and the vukomeričke gorice hilly area, a somewhat urbanized area with arable areas and forests, prone to landslides. weathering-prone marl is a common bedrock in these areas, and the weathered zone can be thick. also, surface flows (streams) can negatively affect the slope stability in these areas. the geological complex of the southern slopes of medvednica mt. contains two areas within the zagreb city area (fig. 6; table 2): the southern slopes (≈ 160.7 km2, ≈ 25% of zagreb city area) and the northeast slopes (≈ 0.7 km2, ≈ 0.1% of zagreb city area). the northern slopes of the vukomeričke gorice hilly area cover ≈ 54.6 km2 (≈ 9% of zagreb city area) (fig. 6; table 2). zone 2 covers ≈ 216 km2 in total (≈ 34% of zagreb city area). the main general geological features are a carbonate and/or clastite composition of the bedrock with variable degrees of lithification (šikić et al., 1978; šikić et al., 1979; basch, 1980a, b; pikija, 1987; croatian geological survey, 2009a, b). the main hydrogeological features are the locally present aquifers with predominantly cavernous and fracture porosity and with low water content (ivković & komatina, 1980; ivković et al., 1983; biondić et al., 2003). the main engineering geological features are that the sediments can be characterized as a transition from rocks to soils, with a weathered zone that is prone to degradation, erosion, sliding, and potential torrent flows (čubrilović et al., 1967; čubrilović, 1969; braun, 2002; miklin et al., 2007; herak et al., 2013; miklin et al., 2018; padovan et al., 2021). the stated geohazards are relatively common phenomena in this area and the expected ground types for this zone are b and c, and locally d and s1 (according to eurocode 8, fig. 6, table 2). therefore, from the perspective of seismic risk assessment, this zone has less favourable geological, hydrogeological, and engineering geological characteristics than zone 1 (table 2). 3.3. zone 3 – elevated deposits zone 3 consists of a wider area of elevated deposits north and south of the sava river. the northern part represents an area between the slopes of medvednica mt. and the sava river’s main area of influence. it is an area with a gentle morphology, which is urbanized but also has arable areas. the southern part has similar characteristics and is located between the area of g eologia c roatica 251podolszki et al.: geozonation of the zagreb city area as an input for seismic risk assessment the sava river’s influence and the slopes of the vukomeričke gorice hilly area. it is an area with a gentle morphology, which is less urbanized and has arable areas. the geological complex of elevated deposits contains two areas within the zagreb city area (fig. 6; table 2): a wide area north of the sava river (≈ 113.4 km2, ≈ 18% of zagreb city area) and a wide area south of the sava river (≈ 66.7 km2, ≈ 10% of zagreb city area). zone 3 covers ≈ 180 km2 in total (≈ 28% of zagreb city area). the main geological features are that the sediments are mostly relatively unconsolidated (šikić et al., 1978; šikić et al., 1979; basch, 1980a, b; pikija, 1987; croatian geological survey, 2009a, b). the main hydrogeological features of these terrains include aquifers with intergranular porosity and with relatively low transmissivity and permeability (ivković & komatina, 1980; ivković et al., 1983; biondić et al., 2003). the groundwater depth is variable with the surface flows and irrigation systems developed in this area. the main engineering geological features are that the sediments can be characterized as transitioning from poorly and non-lithified materials to coherent and non-coherent soils with a weathered zone, which is prone to erosion and local liquefaction (čubrilović et al., 1967; čubrilović, 1969; braun, 2002; miklin et al., 2007; herak et al., 2013; miklin et al., 2018; padovan et al., 2021). the figure 6. a zonation map of the zagreb city area with differentiated geological complexes and ground type assessment (according to eurocode 8). the original scale of the developed map is 1:100,000. horizontal peak ground acceleration (hpga) for ground type a for the period of 475 years in fractions of g (the standard acceleration due to earth's gravity, equivalent to g-force) is marked on the map (purple isolines, after miklin et al., 2019) and major fault lines in the area are presented (red lines, after croatian geological survey, 2009a). measured ground types according to eurocode 8 in the research area within the zagreb city area (a-d, ≈ 175 km2, ≈ 1/4 of zagreb city area, after miklin et al., 2019; table 1) are highlighted on the map. g eo lo gi a c ro at ic a 252 geologia croatica 78/3 expected ground types for this zone are c, and locally d, s1, and s2 (according to eurocode 8, fig. 6; table 2). therefore, from the perspective of seismic risk assessment, this zone has less favourable geological, hydrogeological, and engineering geological characteristics than zone 1 (table 2). 3.4. zone 4 – alluvium zone 4 is the area of influence of the sava river. these plains are urbanized, but arable lands are also present. surface flows are important for this area, including the meandering sava river and some smaller lakes that provide a rich habitat for flora and fauna. the geological complex of alluvial deposits contains an area relatively near the sava river (≈ 155.3 km2, ≈ 24% of zagreb city area, fig. 6; table 2). the main geological features are that the sediments are mainly unconsolidated alluvial gravels, sands, silts, and clays (šikić et al., 1978; šikić et al., 1979; basch, 1980a, b; pikija, 1987; croatian geological survey, 2009a, b). the main hydrogeological features are that these are terrains with aquifers with intergranular porosity of high transmissivity and permeability, and that there is a relatively high groundwater table present (ivković & komatina, 1980; ivković et al., 1983; biondić et al., 2003). the main engineering geological features are that the sediments can be characterized as mainly non-coherent soils, or locally coherent soils that are prone to liquefaction, and that flooding can occur (čubrilović et al., 1967; čubrilović, 1969; braun, 2002; miklin et al., 2007; herak et al., 2013; miklin et al., 2018; padovan et al., 2021). the expected ground types for this zone are c and d, and locally s2 (according to eurocode 8, fig. 6; table 2). therefore, from the perspective of seismic risk assessment, this zone has unfavourable geological, hydrogeological, and engineering geological characteristics (table 2). 4. discussion 4.1. general comments development of any area ought to be planned and be sustainable (mensah, 2019; sale & el kawy, 2021; yang, 2023). there are multiple ways to reach that goal, and one of them is to utilise adequate urban planning and relevant data (lamelas et al., 2009; gong et al., 2021; li et al., 2023; podolszki & karlović, 2023; di salvo et al., 2024). the geozonation of the zagreb county administrative area presented here provides information about the main geological features with the expected characteristic phenomena (geohazard) for each differentiated zone and geological complex. together with the measured or assumed ground type according to eurocode 8, the seismic risk for each differentiated zone and geological complex was assessed for the whole city area. this type of zoning and developed map is a novelty for this region and zagreb county, and this methodology could be used on a regional level for other areas or counties in croatia or other urban areas where similar problems exist and where no previous geozonation has been carried out. for direct application in urban planning, the presented map needs to be upscaled to a scale of 1:25,000 (or greater). this can be achieved by conducting a high-resolution field investigation accompanied by adequate laboratory and cabinet analyses. it should be emphasised that detailed geo-data are the basis for the determination of locally specific geohazards, the conditions under which they occur, and their spatial spread (chacón et al., 2006; corominas et al., 2014; podolszki et al., 2023a; podolszki & karlović, 2023). this type of data is missing for three-quarters of the zagreb city area. the locations of geohazard phenomena (e.g., erosion, falls, slides, torrent flows, liquefaction, floods) are very vulnerable (bell, 2003; gong et al., 2021; podolszki & terzić, 2023) as they could be triggered or reactivated by earthquakes, endangering public safety and causing infrastructure and property damage (pollak et al., 2021; podolszki et al., 2023b). some liquefaction locations and landslide data are available (miklin et al., 2007; miklin et al., 2018), but detailed geo-data would also provide a way to define “subzones” and to further differentiate the defined geological complexes, i.e., to divide the zagreb city area into smaller areas and zones with the same characteristics and to apply these directly in city geohazard management. it is important to note that from detailed and quality data, multiple thematic maps can be developed, and the collected data offer permanent value as a basis for further updates and analysis. however, it is a never-ending process: as new data and techniques become available and/or the research area goes through changes and development, there is always room for improvement of the developed thematic geological maps (in the broadest sense). the best way to cope with geohazards, the seismic risk, and urbanization in the zagreb city area (or any table 2. zagreb city area zonation with data about areas, their relative percentages, seismic risk, expected ground type (according to eurocode 8), and characteristic phenomena for each differentiated zone and geological complex. zone geological complex zagreb city area (km2) percentage (%) seismic risk assessment expected ground type (e8) characteristic phenomena* mountains medvednica mt. ≈90 ≈14 favourable a erosion, falls, and torrent flows slopes southern slopes of medvednica mt. ≈161 ≈25 less favourable b, c (d, s1) erosion, slides, and torrent flowsnorthern slopes of vukomeričke gorice hilly area ≈55 ≈9 elevated deposits elevated deposits (north) ≈113 ≈18 c (d, s1, s2) erosion and liquefa ctionelevated deposits (south) ≈67 ≈10 alluvium sava river alluvium ≈155 ≈24 unfavourable c, d (s2) liquefaction and floods no. of zones = 4 no. of geoc = 6 σ = 641 km2 σ = 100% no. of classes = 3 ground type e is not expected in the area *other phenomena are possible in the area g eologia c roatica 253podolszki et al.: geozonation of the zagreb city area as an input for seismic risk assessment other area) is to conduct geo-research periodically and interdisciplinary research with new technologies applied and up-to-date methodologies. by adopting that approach, green, safe, and sustainable development can be achieved (fig. 7). 4.2. recommendations for further geo-research for the zagreb city area the problem of either non-existent, or insufficient available geo-data was partially solved by a review and analysis of historical geo-data with a new zonation (map) as presented here. still, new, detailed and thorough geo-research is needed for the zagreb city area. this type of research requires relatively large amounts of funding, interdisciplinary teams of researchers, and substantial time. hence, further research should be conducted methodically and in phases, taking into account the zonation presented here, differentiated geological complexes, and their spatial coverage: • phase 1 or the priority should focus on the area of the sava river alluvium, as the area is heavily urbanized and the terrain is saturated with water, which is unfavourable from the perspective of seismic risk. • phase 2 should encompass the area of the southern slopes of medvednica mt. and the area of elevated deposits (north), as these areas are urbanized and a significant landslide risk is present in the hilly area, while in the areas nearer to the sava river, liquefaction can occur. detailed geo-data are available for about two-thirds of the areas, while for the remaining third of the areas, detailed geo-data still need to be collected. from the perspective of seismic risk, these areas are less prone to seismic risk than the area of the sava river alluvium. • phase 3 should include the northern slopes of the vukomeričke gorice hilly area and elevated deposits (south), as these areas are somewhat urbanized and landslides can occur in the hilly area, while in the areas nearer to the sava river, liquefaction can occur in sandy sediments. as these two areas are relatively small, the recommendation is to conduct detailed geo-research for these two areas in a single phase. from the perspective of seismic risk, these areas are less prone to seismic risk than the area of the sava river alluvium. • phase 4 should cover the area of medvednica mt., as the area is not urbanized and covered with forests and “rocky” terrain, which is favourable from the perspective of seismic risk. 4.3. list of specific challenges and broader research context in the presented research, some specific challenges emerged, and they can be divided into research limitations and its strengths. for the executed research, the following can be considered as limitations: • the reviewed maps differ in scale, theme, methodology and available standards. moreover, detailed data was available only for part of the zagreb city area. • geozonation and differentiation of geological complexes were carried out through a reinterpretation and review of previously collected data. • the verification of the results was conducted only in cabinet (desk-based verification). for this research, the following could be considered as strengths: • the presented methodology represents an added value in practical and scientific domains as it demonstrates that accurate and adequate geozonation could be carried out despite the shortcomings in input data (e.g., scale, theme, availability, and resolution). on the developed map four different zones are clearly spatially defined. • the presented results and developed map are already in use in the geohazard management of the zagreb city area, and its practical application is ongoing. • the methodology (a review of existing geo-data in order to develop a new and up-to-date product) could be applied elsewhere in croatia or even wider areas where no previous geozonation was carried out and the available detailed geo-data is scarce. • although the research provided improvements in the existing geozonation and available geo-data, future improvements and enhancements of the presented map and geo-data set are still possible with the application of field, laboratory and cabinet research. • in that sense, recommendations for further geo-research for the zagreb city area were made. the presented research focused on the update and moderni sation of the existing geozonation, providing a comprehensive knowledge base for further research focusing on geohazard mitigation as well as safe and sustainable urban planning. hence, in the broader context, there is a relationship with studies regarding mass movements vulnerability and risk assessments on infrastructures (ali et al., 2023), landslide susceptibility assessments and geohazard maps used in urban management (cemiloglu et al., 2023), development of multi-hazard hotspot maps which can be used as a tool for planning actions aimed at reducing the vulnerability and exfigure 7. the never-ending process cycle of geo-research contributing towards green, safe, and sustainable development. g eo lo gi a c ro at ic a 254 geologia croatica 78/3 posure level of the urban population (di salvo et al., 2024), assessment of geohazards for the purposes of preparedness, mitigation or future planning and development control (hart & hearn, 2018) and in integrating economic, ecological and social criteria with geoscientific factors (lamelas et al., 2009). 5. conclusion the zagreb city area is relatively large and geologically diverse. based on the available geological data and small-scale maps, new geozonation for this area was conducted and a new regional map at a scale of 1:100,000 was developed. the developed map gives insights into geological conditions in the area and differentiates four zones with six geological complexes. based on the reviewed geological, hydrogeological, and engineering geological data, characteristic geohazard and ground type assessment according to eurocode 8 were defined for each differentiated geological complex, providing a comprehensive guideline contributing to the local and regional seismic risk assessment. for direct use in urban planning, the developed map needs to be upscaled to 1:25,000 (or larger) with detailed geo-data (currently non-existent or unavailable for the whole research area). to achieve this goal, recommendations for further research (in phases) have been given. however, the zonation presented here and the resulting map mark, an important step towards the geohazard management and sustainable development of the zagreb city area, with the map already in use by the local government. moreover, the methodology (a review of existing geo-data in order to develop a new and up-to-date product) could be applied in areas where similar conditions and issues prevail and where no previous geozonation was carried out. the proposed methodology is also practically applicable in other disciplines (not just geology and geohazards management), including urban planning, eco nomics, civil engineering, and civil protection. in the wake of on-going climate changes, the proposed methodology is of significant importance, as it facilitates and improves the early-stage geological research of an area(s) with limited geo-data. acknowledgment the authors would like to express their thanks to the: (i) h2020-widespread-05-2017-twinning project (project acronym: geotwinn, project id: 809943) and its members, with special thanks to the project for supporting open access; (ii) city of zagreb and all of the experts and researchers who conducted studies on the zagreb city area, providing results and insights; (iii) and colleagues from hgi-cgs who helped with this research in any form. references ali, s.a., mohajane, m., parvin, f., varasano, a., hitouri, s., łupikasza, e. & pham, q.b. (2023): mass movement susceptibility prediction and infrastructural risk assessment (ira) using gis-based meta classification algorithms.– applied soft computing, 145, 110591. https://doi.org/10.1016/j.asoc.2023.110591 bačić, m. & kadiri, a. (2020): estimation of ground motion amplification for the case of albania earthquake 26th november 2019.– in: symposium of the phd studies of the faculty of civil engineering – croatia. https:// doi.org/10.5592/co/phdsym.2020.05 basch, o. (1980a): osnovna geološka karta sfrj 1:100.000, list ivanić-grad l33-81 [basic geological map of sfry 1:100 000, ivanić-grad sheet l33-81 – in croatian].– institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd. basch, o. (1980b): osnovna geološka karta sfrj 1:100.000. tumač za list ivanić-grad l33-81 [basic geological map of sfry 1:100 000. explanatory notes for the ivanić-grad sheet l33-81 – in croatian].– institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd. bell, f.g. (2003): geological hazards: their assessments, avoidance and mitigation; e&fn spon press: london, uk, 2003; 1–648. beroza, g.c. & kanamori, h. (2015): earthquake seismology: an introduction and overview.– in: schubert, g. (ed.): treatise on geophysics, 2nd edition. elsevier, 4, 1–150. https://doi.org/10.1016/b978-0444-53802-4.00069-5 bešlić, ž., kožul, m., šaravanja, r., šola, m., palčić, m. & mudronja, k. (2023): zagreb u brojkama 2023 [zagreb in number 2023 – in croatian]. grad zagreb, gradski ured za gospodarstvo, ekološku održivost i strategijsko planiranje, sektor za strategijske informacije i istraživanja, odjel za statističke i analitičke poslove. biondić, b., brkić, ž. & biondić, r. (2003): republika hrvatska – hidrogeološka karta u mjerilu 1:300.000 [republic of croatia – hydrogeological map in scale of 1:300,000 – in croatian].– croatian geological survey, zagreb, croatia. bostjančić, i., filipović, m., gulam, v. & pollak, d. (2021): regional-scale landslide susceptibility mapping using limited lidarbased landslide inventories for sisak-moslavina county, croatia.– sustainability, 13, 4543. https://doi.org/10.3390/su13084543 braun, k. (2002): republika hrvatska – inženjerskogeološka karta u mjerilu 1:300.000 [republic of croatia – engineering geological map in scale of 1:300,000 – in croatian].– croatian geological survey, zagreb, croatia. cemiloglu, a., zhu, l., mohammednour, a.b., azarafza, m. & nanehkaran, y.a. (2023): landslide susceptibility assessment for maragheh county, iran, using the logistic regression algorithm.– land, 12, 1397. https://doi.org/10.3390/land12071397 chacón, j., irigaray, c., fernández, t. & el hamdouni, r. (2006): engineering geology maps: landslides and geographical information systems.– bulletin of engineering geology and the environment, 65, 341–411. https://doi.org/10.1007/s10064-006-0064-z chaminé, h.i., carvalho, j.m., teixeira, j. & freitas, l. (2015): role of hydrogeological mapping in groundwater practice: back to basics.– european geologist, 40, 34–42. chaudhary, m.t. & piracha, a. (2021): natural disasters – origins, impacts, management.– encyclopedia, 1, 1101–1131. https://doi. org/10.3390/encyclopedia1040084 compton, r.r. (2016): geology in the field.– wiley, cape town, south africa. constantinescu, r., gonzález-zuccolotto, k., ferrés, d., sieron, k., siebe, c., connor, c., capra, l. & tonini, r. (2022): probabilistic volcanic hazard assessment at an active but undermonitored volcano: ceboruco, mexico.– journal of applied volcanology, 11, 1–20. https://doi.org/10.1186/s13617-022-00119-w corominas, j., van westen, c., frattini, p., cascini, l., malet, j.p., fotopoulou, s., catani, f., van den eeckhaut, m., mavrouli, o., agliardi, f., pitilakis, k., winter, m.g., pastor, m., ferlisi, s., tofani, v., hervás, j. & smith, j.t. (2014): recommendations for the quantitative analysis of landslide risk.– bulletin of engineering geology and the environment, 73, 209–263. https://doi.org/10.1007/s10064-013-0538-8 crane, j.m. (2013): effects of stress and water saturation on seismic velocity and attenuation in near surface sediments.– unpubl. phd thesis, louisiana state university and agricultural and mechanical college, louisiana, usa. https://doi.org/10.31390/gradschool_dissertations.3714 croatian geological survey (2009a): geološka karta republike hrvatske 1:300.000 [geological map of croatia 1:300,000 – in croatian].– croatian geological survey, zagreb, croatia. g eologia c roatica 255podolszki et al.: geozonation of the zagreb city area as an input for seismic risk assessment croatian geological survey (2009b): tumač geološke karte republike hrvatske 1:300.000 [explanatory notes for the geological map of croatia 1:300,000 – in croatian].– croatian geological survey, zagreb, croatia. cuervas-mons, j., zêzere, j.l., domínguez-cuesta, m.j., barra, a., reyes-carmona, c., monserrat, o., oliveira, s.c. & melo, r. (2022): assessment of urban subsidence in the lisbon metropolitan area (central-west of portugal) applying sentinel-1 sar dataset and active deformation areas procedure.– remote sensing, 14, 4084. https://doi.org/10.3390/rs14164084 čubrilović, p (1969): tumač inženjerskogeološke karte jugoslavije 1:500.000 [explanatory notes for engineering geological map of yugoslavia 1:500,000 – in croatian].– savezni geološki zavod, beograd. čubrilović, p., palavestrić, l.j. & nikolić, t. (1967): inženjerskogeološka karta jugoslavije 1:500.000 [engineering geological map of yugoslavia 1:500,000 – in croatian].– savezni geološki zavod, beograd. dearman, w.r. & fookes, p.g. (1974): engineering geological mapping for civil engineering practice in the united kingdom.– quarterly journal of engineering geology, 7, 223–256. https://doi.org/10.1144/gsl. qjeg.1974.007.03.0 di salvo, c., ciotoli, g., mancini, m., nisio, s. & stigliano, f. (2024): analysis of geological multi-hazards in an urban district.– geosciences, 14, 27. https://doi.org/10.3390/geosciences14020027 dong, l. & luo, q. (2022): investigations and new insights on earthquake mechanics from fault slip experiments.– earth sciende reviews, 228, 104019. https://doi.org/10.1016/j.earscirev.2022.104019 el aal, a.k.a., nabawy, b.s., aqeel, a. & abidi, a. (2020): geohazards assessment of the karstified limestone cliffs for safe urban constructions, sohag, west nile valley, egypt.– journal of african earth sciences, 161, 103671. https://doi.org/10.1016/j.jafrearsci.2019.103671 ferreira, t.m. & lourenço, p.b. (2019): disaster risk reduction and urban resilience: concepts, methods and applications.– in: farsangi, n.e., takewaki, i., yang, t., astaneh-asl, a. & gardoni, p. (eds.): resilient structures and infrastructure. springer, singapore. https://doi.org/10.1007/978-981-13-7446-3_17 galván aguilar, e.l. & chávez, o.e. (2012): geological mapping.– geology community newsletter, 1/1, 4–5. gong, w., juang, c.h. & wasowski, j. (2021): geohazards and human settlements: lessons learned from multiple relocation events in badong, china – engineering geologist's perspective.– engineering geology, 285, 106051. https://doi.org/10.1016/j.enggeo.2021.106051 gverić, z., tomašić, n., durn, g. & rubinić, v. (2024): the influence of weathering and pedogenesis on the geochemical record of miocene marls and plio-quaternary sediments, medvednica mt., croatia.– geologia croatica, 77, 3, 311–323. https://doi.org/10.4154/gc.2024.17 hart, a.b. & hearn, g.j. (2018): mapping geohazards in the watersheds above leh, ladakh: the use of publicly-available remote sensing to assist risk management.– international journal of disaster risk reduction, 31, 789–798. https://doi.org/10.1016/j.ijdrr.2018.07.021 herak, m., miklin, ž., allegrett, i., dasović, i., fiket, t., herak, d., ivančić, i., kuk, k., kuk, v., marić, k., markušić, s., prevolnik, s., podolszki, l., sović, i. & stipčević, j. (2013): seizmičko i geološko mikrozoniranje prema standardima eurokoda 8 za zapadni dio podsljemenske urbanizirane zone [seismic and geological micro zonation according to eurocode 8 for the western part of podsljeme urban area – in croatian].– university of zagreb, faculty of science, zagreb. ivković, a. & komatina, m. (1980): hidrogeološka karta sfrj 1:500.000 [hydrogeological map of sfry 1:500,000 – in croatian].– savezni geološki zavod, beograd. ivković, a., šarin, a. & komatina, m. (1983): tumač za hidrogeološku kartu sfrj 1:500.000 [explanatory notes for the hydrogeological map of sfry 1:500,000 – in croatian].– savezni geološki zavod, beograd. jurak, v., ortolan, ž., ivšić, t., herak, m., šumanovac, f., vukelić, i., jukić, m. & šurina, z. (2008): geotehničko i seizmičko mikrozoniranje grada zagreba – pokušaji i ostvarenje [geotechnical and seismic microzonation of zagreb – attempts and realization – in croatian].– in: proceedings of the development of zagreb city – croatia 2008. kahraman, s. (2019): the effect of water saturation on the p-wave velocity of sedimentary rocks.– in: proceedings of the 23rd international congress on acoustics – aachen, germany, 2019. kurečić, t., kovačić, m. & grizelj, a. (2021): mineral assemblage and provenance of the pliocene viviparus beds from the area of vukomeričke gorice, central croatia.– geologia croatica, 74, 3, 253– 271. https://doi.org/10.4154/gc.2021.16 lamelas, m.t., hoppe, a., de la riva, j. & marinoni, o. (2009): modelling environmental variables for geohazards and georesources assessment to support sustainable land-use decisions in zaragoza (spain).– geomorphology, 111/1–2, 88–103. https://doi.org/10.1016/j.geomorph.2008.10.021 levchenko, d.g. (2006): effect of the water-saturated sediment layer on recording seismic signals with a bottom seismometer.– oceanology, 46, 739–750. https://doi.org/10.1134/s0001437006050146 li, s., peng, l., wang, x., huang, k. & tang, j. (2023): do geohazards inhibit urban expansion at the regional scale? evidence from a counterfactual analysis in southwest china.– cities, 142, 104558. https://doi. org/10.1016/j.cities.2023.104558 markušić, s., stanko, d., korbar, t., belić, n., penava, d. & kordić, b. (2020): the zagreb (croatia) m5.5 earthquake on 22 march 2020.– geosciences, 10, 252. https://doi.org/10.3390/geosciences10070252 mensah, j. (2019): sustainable development: meaning, history, principles, pillars, and implications for human action: literature review.– cogent social sciences, 5, 165353. https://doi.org/10.1080/23311886.2019.16535 3 miklin, ž., mlinar, ž., brkić, ž. & hećimović, i. (2007): detaljna inženjerskogeološka karta podsljemenske urbanizirane zone mjerila 1:5.000 (digk-faza i) [detailed engineering–geological map of podsljeme urban area 1:5000 (phase i) – in croatian].– croatian geological survey, zagreb, croatia. miklin, ž., podolszki, l., novosel, t., sokolić, ž., sokolić, i., ofak, j., padovan, b. & zailac, k. (2018): detaljna inženjerskogeološka karta podsljemenske urbanizirane zone mjerila 1:5000 (digk-faza ii) [detailed engineering–geological map of podsljeme urban area 1:5000 (phase ii) – in croatian].– croatian geological survey, zagreb, croatia. miklin, ž., podolszki, l., novosel, t., sokolić, i., ofak, j., padovan, b. & sović, i. (2019): studija: seizmička i geološka mikrozonacija dijela grada zagreba [study: seismic and geological micro zonation of the part of the city of zagreb area – in croatian].– croatian geological survey, zagreb, croatia. mišur, i., balen, d., klötzli, u., belak, m., massone, h.-j., brlek, m. & brčić, v. (2023): petrochronological study of chloritoid schist from medvednica mountain (zagorje mid-transdanubian zone, croatia).– geologia croatica, 76/1, 13–36. https://doi.org/10.4154/ gc.2023.02 padovan, b., podolszki, l., sokolić, i., sović, i., novosel, t., pivčević, n. & kosović, i. (2021): seismic and geological zonation of the part of the city of zagreb area.– in: lakušić, s. & atalić, j (eds.): proceedings of the 1st croatian conference on earthquake engineering 1crocee 2021 – croatia, 2021. https://doi.org/10.5592/ co/1crocee.2021.26 pikija, m. (1987): osnovna geološka karta sfrj 1:100.000, list sisak l 3393 [basic geological map of sfry 1:100,000, sisak sheet l 33-93 – in croatian].– savezni geološki zavod, beograd. podolszki, l. & karlović, i. (2023): remote sensing and gis in landslide management: an example from the kravarsko area, croatia.– remote sensing, 15, 5519. https://doi.org/10.3390/rs15235519 podolszki, l. & terzić, j. (2023): procjena potresnog rizika grada zagreba – geološki elaborat [zagreb city seismic risk assessment – geog eo lo gi a c ro at ic a 256 geologia croatica 78/3 logical report – in croatian].– croatian geological survey, zagreb, croatia. podolszki, l., miklin, l., kosović, i. & gulam, v. (2023a): multilevel data analyses in the gajevo landslide research, croatia.– remote sensing, 15, 200. https://doi.org/10.3390/rs15010200 podolszki, l., pollak, d., frangen, t. & kosović, i. (2023b): what we could learn from petrinja 2020 earthquake coseismic ground failures?– in: proceedings of the 9th conference of croatian geotechnical society – croatia 2023. pollak, d., gulam, v., novosel, t., avanić, r., tomljenović, b., hećej, n., terzić, j., stipčević, j., bačić, m., kurečić, t., dolić, m., bostjančić, i., wacha, l., kosović, i., budić, m., vukovski, m., belić, n., špelić, m., brčić, v., barbača, j., kordić, b., palenik, d., filjak, r., frangen, t., pavić, m., urumović, k., sečanj, m., matoš, b., govorčin, m., kovačević, m.s. & librić, l. (2021): the preliminary inventory of coseismic ground failures related to december 2020 – january 2021 petrinja earthquake series.– geologia croatica, 74, 2, 189–208. https:// doi.org/10.4154/gc.2021.08 price, d.g. (2009): engineering geology – principles and practice.– springer, berlin, germany. rahman, r.m., shi, z.h. & chongfa, c. (2009): soil erosion hazard evaluation – an integrated use of remote sensing, gis and statistical approaches with biophysical parameters towards management strategies.– ecological modelling, 220, 13–14, 1724–1734. https://doi.org/10.1016/j. ecolmodel.2009.04.004 sale, d. & el kawy, a.a. (2021): problematic soil risk assessment approach for sustainable spatial suitability of urban land use in new cities by using gis and remote sensing: a case study of new east port said city.– international journal of sustainable development and planning, 16, 4, 615–628. https://doi.org/10.18280/ijsdp.160402 seville, e. & metcalfe, j. (2005): developing hazard risk assessment framework for the new zealand state highway network.– land transport new zealand research report, 276, 1–80. slovenec, d., halamić, j. & šegvić, b. (2024): middle triassic basaltic pyroclastic rocks from the mt. medvednica ophiolitic mélange (nw croatia): petrology, geochemistry and tectono-magmatic setting.– geologia croatica, 77, 2, 57–68. https://doi.org/10.4154/gc.2024.06 struckmeier, w.f. & margat, j. (1995): hydrogeological maps – a guide and a standard legend.– international association of hydrogeologists, hannover, germany. šikić, k., basch, o. & šimunić, a. (1978): osnovna geološka karta sfrj 1:100.000, list zagreb l 33-80 [basic geological map of sfry 1:100 000, zagreb sheet l 33-80 – in croatian].– institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd. šikić, k., basch, o. & šimunić, a. (1979): osnovna geološka karta sfrj 1:100 000. tumač za list zagreb l 33-80 [basic geological map of sfry 1:100 000. explanatory notes for the zagreb sheet l 33-80 – in croatian]. institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd. teixeira, j., chaminé, h.i., carvalho, j.m., pérez-alberti, a. & rocha, f. (2013): hydrogeomorphological mapping as a tool in groundwater exploration.– journal of maps, 9, 2, 263–273. https://doi.or g/10.1080/17445647.2013.776506 toksöz, m.n., cheng, c.h. & timur, a. (1976): velocities of seismic waves in porous rocks.– geophysics, 41, 621–645. https://doi. org/10.1190/1.1440639 twisdale, l.a. & vickery, p.j. (1995): extreme-wind risk assessment.– in: sundararajan, c. (ed): probabilistic structural mechanics handbook. springer, boston, usa. https://doi.org/10.1007/978-14615-1771-9_20 university of zagreb (2024): seizmološki pojmovnik [seismic glossary – in croatian].– university of zagreb, faculty of science. vamvakaris, d.a., papazachos, c.b., papaioannou, c.a., scordilis, e.m. & karakaisis, g.f. (2016): a detailed seismic zonation model for shallow earthquakes in the broader aegean area.– natural hazards and earth systems sciences, 16, 55–84. https://doi. org/10.5194/nhess-16-55-2016 varnes, d.j. (1974): the logic of geological maps, with reference to their interpretation and use for engineering purposes.– usgs professional paper, 837, alexandria, usa. yang, l. (2023): sustainable city planning and development: transport and land use.–sustainability, 15, 15804. https://doi.org/10.3390/su152215804 zaccagnino, d. & doglioni, c. (2022): the impact of faulting complexity and type on earthquake rupture dynamics.– communications earth & environment, 3, 258, 1–10. https://doi.org/10.1038/s43247-02200593-5 zhou, x., wu, w., lin, z., zhang, g., chen, r., song, y., wang, z., lang, t., qin, y., ou, p., huangfu, w., zhang, y., xie, l., huang, x., fu, x., li, j., jiang, j., zhang, m., liu, y., peng, s., shao, c., bai, y., zhang, x., liu, x. & liu, w. (2021): zonation of landslide susceptibility in ruijin, jiangxi, china.– international journal of environmental research and public health, 18, 5906. https://doi. org/10.3390/ijerph18115906 web source: en 1998-1:2004 (2005): eurocode 8: design of structures for earthquake resistance – part 1: general rules, seismic actions and rules for buildings.– european commission, bruxelles, belgium. available at: https://eurocodes.jrc.ec.europa.eu/en-eurocodes/eurocode-8-designstruc tures -earth quake-resistance. accessed on: february 3rd, 2024. https://doi.org/10.3390/ijerph18115906 https://doi.org/10.3390/ijerph18115906 https://eurocodes.jrc.ec.europa.eu/en-eurocodes/eurocode-8-design-structures-earthquake-resistance https://eurocodes.jrc.ec.europa.eu/en-eurocodes/eurocode-8-design-structures-earthquake-resistance https://eurocodes.jrc.ec.europa.eu/en-eurocodes/eurocode-8-design-structures-earthquake-resistance 2016 | 69/2 | 213–229 | 8 figs. | 1 tab. | 3 pls. | www.geologia-croatica journal of the croatian geological survey and the croatian geological society 1. introduction study of ostracods of the neogene paratethys has substantially contributed to the stratigraphic, environmental, and palaeogeographic understanding of this huge and complex marine to lacustrine depositional system (danielopol et al., 2008a). of the large brackish lakes that repeatedly formed during the history of the paratethys, the late miocene-early pliocene lake pannon was probably the longest-lived (müller et al., 1999; harzhauser & mandic, 2008). as a consequence, this lake was inhabited by an astonishingly diverse lacustrine biota (e.g. papp et al., 1985; stevanović et al., 1990). the dominantly endemic ostracods of lake pannon have been studied and described by generations of palaeontologists, starting with reuss (1850), and leading to the introduction of ca. 500 new species. the taxonomy, environmental requirements, and palaeogeographic distribution of these ostracods, however, is far from being well understood, and needs further study (danielopol et al., 2008a). in particular, the transylvanian basin (tb), representing the easternmost part of the early lake pannon, lacks modern and well-illustrated documentation of the endemic ostracod taxa. the objective of this paper is to present the late miocene (pannonian) ostracod faunas from several outcrops of the southwestern tb, and to explore their palaeoecological, palaeobiogeographic and biostratigraphic context. 2. neogene evolution of the transylvanian basin the tb is bordered by the eastern and southern carpathians, and the apuseni mountains (fig. 1). the basin fill can be divided into several tectono-stratigraphic megasequences (krézsek, 2005; krézsek & bally, 2006), the uppermost one of which pannonian ostracods from the southwestern transylvanian basin erika kovács1, imre magyar2,3, orsolya sztanó4 and radovan pipík1 1 slovak academy of sciences, earth science institute, ďumbierska 1, 974 01 banská bystrica, slovak republic; (kovacs@savbb.sk; pipik@savbb.sk) 2 mol hungarian oil and gas plc., október 23. utca 18, 1117 budapest, hungary; (corresponding author: immagyar@mol.hu) 3 mta-mtm-elte research group for paleontology, h-1431 budapest, pob 137. 4 eötvös loránd university, department of physical and historical geology, pázmány péter sétány 1/c, h-1117 budapest, hungary; (sztano@ludens.elte.hu) doi: 10.4154/gc.2016.16 abstract pannonian (late miocene) ostracods were investigated from 7 outcrops, exposing deep-water lacustrine sediments along the western margin of the transylvanian basin. sedimentological patterns in the outcrops indicate deposition in sublittoral to profundal environments where finegrained, suspension fall-out sediments are intercalated with various types of mass transport deposits, most commonly turbidites. the ostracod fauna, consisting of 30 taxa, is dominated by endemic species of the brackish lake pannon. the assemblages indicate a mixture of deepwater (sublittoral to profundal) species, such as paratethyan candoninae, and shallow-water (littoral) species, belonging to cyprideis, loxoconcha, amnicythere and hemicytheria. the mixed character of the assemblages is most probably a consequence of the reworking of littoral specimens into deeper environments, a phenomenon also observed in the molluscan fauna from some of the investigated outcrops. alternatively, some endemic and extinct species of the littoral ge nera might have adapted to the deep-water environment. a significant decrease in the abundance and diversity of ostracods from west to east is interpreted reflecting increasingly distal environments. the ostracod fauna indicates the hemicytheria hungarica (2 outcrops), hemicytheria tenuistriata (3 outcrops), and propontoniella candeo zones (2 outcrops) of the lower pannonian slavonian substage. comprises the middle and upper miocene (badenian, sarmatian and pannonian central-paratethys stages). the middle miocene to quaternary evolution of the tb is related to the carpathian orogene (royden, 1988; schmid et al., 2008). during this period it evolved as a compressional back-arc basin (de broucker et al., 1998; ciulavu, 1999; sanders et al., 1999; krézsek et al., 2010), and its sedimentary history was connected to the subduction along the carpathian arc. although a very high rate of subsidence is encountered during this period, no major extensional faults are reported; instead, most structures are related to salt-tectonics (krézsek & bally, 2006). middle badenian evaporites are widespread in the subsurface of the entire tb (gher gari et al., 1991; kováč et al., 2007), and salt tectonics was most effective from the sarmatian to the pliocene (krézsek & bally, 2006). following the fully marine conditions of the badenian and restricted marine environment in the sarmatian, the uplift of the carpathians closed the gateways between the central and eastern paratethys at the end of the middle miocene and thus isolated the intra-carpathian region from the rest of the paratethys (ter borgh et al., 2013). with the onset of the late miocene pannonian age, the tb became part of the large brackish lake pannon (magyar et al., 1999). the sarmatian−pannonian boundary in the tb was traced in a large outcrop of marls and turbiditic sandstones in oarba de mureş (sztanó et al., 2005), on the basis of dinoflagellate biostratigraphy (sütő-szentai & szegő, 2008), magnetostratigraphy and radiometric dating (vasiliev et al., 2010), and foraminifer and ostracod biostratigraphy (filipescu et al., 2011). the boundary was unanimously marked on the basis of microfossils. although the magnetostratigraphic interpretation of the measured polarity pattern is contradictory, high-precision radiometric dating of a volcanic ash deposit from the very top of article history: manuscript received july 18, 2015 revised manuscript accepted april 17, 2016 available online june 01, 2016 keywords: ostracoda, biostratigraphy, late miocene, pannonian, transylvanian basin g eo lo gi a c ro at ic a geologia croatica 69/2214 the one-km-thick sarmatian sequence (vasiliev et al., 2010) indicates that the sarmatian-pannonian boundary is about 11.6 ma old, in accordance with recent magnetostratigraphic interpretations from the vienna basin (paulissen et al., 2011) and the pannonian basin proper (ter borgh et al., 2013). after the isolation event, the water level of lake pannon gradually rose, controlled both by increased precipitation and subsidence all over the pannonian basin system (magyar et al., 1999; garcia-castellanos, 2006; harzhauser et al., 2008). pulses of tectonic uplift with short wave lengths are recorded by coarse-grained fan delta systems along the basin margins (maţenco et al., 2010). these fan deltas prograding from the carpathians and from the apuseni mts. toward the basin centre fed the deep-lacustrine turbidite systems interfingering with hemipelagics/profundal marls. sedimentary facies of the pannonian deposits thus reflect deposition in a deep lacustrine setting, including lacustrine deep-water fans (krézsek & filipescu, 2005; sztanó et al., 2005; krézsek et al., 2010). shallowwater deposits are subordinate and were preserved mostly in the eastern part of the basin. the final infill of the basin did not take place until the end of the miocene, but these deposits are seldom preserved, except where covered by back-arc volcanics (kré zsek and filipescu, 2005; maţenco et al., 2010; krézsek et al., 2010). apart from pliocene lacustrine sediments in the southeastern corner of the tb (for a modern review see harzhauser & mandić, 2008), late miocene lake pannon sediments are the youngest deposits in the basin fill succession. their presentday thickness is usually less than 500 m (krézsek et al., 2010). due to pliocene to quaternary uplift, more than 500 m of sediments have been eroded particularly in the northernmost part of the tb (de broucker et al., 1998; krézsek & filipescu, 2005). erosion is still active today in the basin, where the altitude varies between 300 and 600 m above sea level (maţenco et al., 2010). 3. pannonian ostracods from the transylvanian basin the first contribution to the knowledge of pannonian ostracods of the tb was provided by héjjas (1894), who considered this fauna special and isolated. his observation that the ostracod fauna indicates deep water environment was ahead of his time (wanek, 1992a). chintăuan (1971) investigated pannonian ostracods from the western part of munţii bârgăului. clichici (1980) described an ostracod association from near the aiud river. this fauna, representing the c-d-e zones of the pannonian (filipescu, 1999) included: erpetocypris abscissa (pokorný), can dona trapezoidea (méhes), candona sp., loxoconcha gra­ nifera (reuss) and leptocythere auriculata (méhes). wanek (1992b) investigated the sarmatian and pannonian ostracod fauna of the tb and compared his results with the data of héjjas (1894). he concluded that the complete sarmatian and the slavonian substage of the pannonian could be identified in the tb. olteanu (in popescu, 1995) mentioned some „upper pannonian−pontian” ostracod taxa from lopadea veche: amplo­ cypris abscissa (reuss), a. recta (reuss), pannonocypris auri­ culata [=herpetocyprella auriculata] (reuss), lineocypris tra­ pezoidea (zalányi), hemicytheria josephinae (kollmann), cas piocypris pontica (sokaĉ), cyprideis pannonica (méhes). wanek & filipescu (1994) reported an upper slavonian ostracod assemblage from moldoveneşti. a diverse lower pannonian ostracod fauna was described from ormeniş by wanek (in filipescu, 1996); the fauna was composed of hungarocy p­ ris auriculata [=herpetocyprella auriculata] (reuss), amplo­ cypris reticulata (héjjas), candona (typhlocypris) cf. redunca (zalányi), c. (caspiocypris) transilvanica héjjas, c. (cas­ piocypris) improba krstić, leptocythere (amnicythere) para lella (méhes), leptocythere (amnicythere) rodrigera (pokorný), leptocythere (amnicythere) servica krstić, loxoconcha rhom­ bovalis pokorný, l. porosa (méhes), loxocorniculina ho­ donica pokorný, graptocythere loerentheyi méhes, hemi­ cytheria folliculosa (reuss), and limnocythere aff. aquaensis carbonnel. at oarba de mureş (section a), filipescu et al. (2011) marked the sarmatian−pannonian boundary at the first occurrence of ostracod assemblages containing deep-water species of the amplocypris­candona group. de leeuw et al. (2013) tried to obtain better age constraints on the middle to late miocene central paratethyan regional stages (badenian, sarmatian and pannonian) through integrated mag netostratigraphic, radio-isotopic and biostratigraphic research in transylvania. at mediaş, sighişoara, and târnăveni, the ostracod assemblages indicated a pannonian age. in the case of viforoasa and şoimuş, 3 ostracod biozones were identified following the zonation of krstić (1985): the propontoniella candeo zone, indicating the uppermost part of the slavonian substage, and the amplocypris abscissa and hemicytheria croatica zones, indicating the lower part of the serbian substage. 4. material and methods we have selected 7 outcrops from the southwestern part of the tb, where description of the sedimentary facies and interpretation of the depositional environment was followed by sampling for ostracods, preferably from fine-grained sediments where in situ burial of the shells seemed more probable. altogether 10 micropaleontological samples (250 g air-dried material) were collected. these samples were washed in hydrogen peroxide (10%), sieved using a 150 μm sieve and oven dried. after a preliminary observation under stereomicroscope, the ostracods were examined and photographed using a scanning electron microscope. a jeol jee 4b vacuum evaporator was used for deposition of gold on the surface of specimens. pictures were taken with sem (amray 1830) at an accelerating voltage of 20kv in the sem laboratory of the department of petrology and geochemistry, eötvös loránd university, budapest. all the ostracod valves, both adults and juveniles, whole and broken specimens were counted from each sample. 5. the investigated outcrops and their ostracod fauna 5.1. the lopadea veche/oláhlapád locality this sampled outcrop is located 1 km east of the lopadea stream valley (46°22’45.36”n, 23°39’55.74”e) (fig. 1). lopadea veche belongs to the best studied pannonian exposures in the tb (lőrenthey, 1893; koch, 1900; pávay-vajna, 1910; gillet, 1943; ilie, 1952; lubenescu & lubenescu, 1976; olteanu in popescu, 1995). today several small outcrops can be found in the hilly outskirts of the village. they expose an alternation of argillaceous marl and yellow, fine-medium-grained sands, building a 7−8 m thick succession (fig. 2). given the lack of specific sedimentary structures it is difficult to decide if the sand was transported by gravity-driven processes or just currents/waves/storms. both the marls and the sandstones are friable and the carbonate cementag eologia c roatica kovács et al.: pannonian ostracods from the southwestern transylvanian basin 215 tion is poor. the thickness of sand layers increases upwards from 2−3 cm to 10−15 cm. along the bedding planes plant fragments, branches, and poorly preserved leaf imprints occur together with a rich mollusc assemblage equally consisting of deep-water (con­ geria banatica r. hörnes, paradacna cf. lenzi (r. hörnes), undulotecha pancici (brusina)) and shallow-water forms (me­ lanopsis vindobonensis fuchs). our sample was collected from a marl bed in the lower part of the outcrop (fig. 2). the ostracod association is well preserved and evenly distributed in the argillaceous marl, reflecting autochthonous or alfigure 2. lopadea veche; a – alternation of argillaceous marl and yellowish, fineand medium-grained sand layers, several cm in thickness. white dot indicates sampling location. b – close-up view of the sampled argillaceous marl. figure 1. geological map of the transylvanian basin with the distribution of pannonian sediments and location of the sampled outcrops (adapted from de leeuw et al., 2013). g eo lo gi a c ro at ic a geologia croatica 69/2216 most autochthonous burial. this material consists of 173 valves and carapaces, the latter representing 10% of the specimens; juvenile individuals are subordinate in the sample. the assemblage is rich in species, including amplocypris cf. reticulata (pl. 1, figs. 20–22), a. sp., herpetocyprella hieroglyphica (méhes), can­ dona (caspiolla) praebalcanica krstić, hemicytheria follicu­ losa, cyprideis pannonica (pl. 3, figs. 5–8), loxocorniculina ho­ donica, candona (typhlocypris) trigonella (héjjas) (pl. 1, figs. 29−32), candona (propontoniella) sp., and candona (caspiocy­ pris) transilvanica (fig. 8). the most common genera are amplo­ cypris and herpetocyprella. species of cyprideis, loxoconcha and related genera typify marginal ostracod assemblages world-wide (boomer & eisenhauer, 2002; boomer et al., 2005). according to krstić and stancheva (1990), cyprideis is common in the marginal parts of the pannonian basin, but missing from the deep basins. cyprideis is therefore an indicator of shallow waters. it inhabits mostly brackish (mesohaline) environments, showing the greatfigure 3. gârbova de jos; a – alternation of clast-supported, graded conglomerates, pebbly mudstones, and mud-clast conglomerates; the outcrop is cut by a large normal fault. white dot indicates sampling location. b and c – thin bedded turbidites (fine-grained, graded sandstone beds and mudstone with mud clasts). g eologia c roatica kovács et al.: pannonian ostracods from the southwestern transylvanian basin 217 figure 4. gârboviţa; a – alternation of marl beds and mediumto very fine-grained, graded sandstone layers. b – close-up view of the marl layers, stained by organic matter. white dot indicates sampling location. figure 5. mihalţ. decimetre to metre thick, massive or laminated marl layers intercalated with thin sandstone beds. white dot indicates sampling location. g eo lo gi a c ro at ic a geologia croatica 69/2218 est abundance at salinities of 2−16.5‰ (wagner, 1964), but certain species of the genus may adapt to hypersaline environments (meisch, 2000). pannonian assemblages with cyprideis, amplocypris, amnicythere, hemicytheria and loxoconcha were probably highly tolerant of fluctuations in salinity: they occupied estuaries, i.e. semi-enclosed coastal water bodies with a salinity gradient from brackish to freshwater, in the southern part of the pannonian basin (e.g. kolubara basin in northwestern serbia; rundić, 2006). loxocorniculina is known from brackish water ostracod assemblages of the paratethys and the eastern mediterranean (pipík & bodergat, 2004). according to korecz (1991), candona (caspiolla) praebalcanica inhabited pliomesohaline environments, with 15−80 m water depth, and candona (caspiocypris) transilvanica inhabited shallow but calm environments. the entire ostracod assemblage shows a mixture of shallow and deep-water species, probably as a result of redeposition of littoral forms into deeper parts of the basin. candona (caspiolla) praebalcanica appears in our material with complete carapaces filled with sediment, a phenomenon indicating rapid burial (holmes, 2001). otoliths and fish teeth also occur in the microfauna (pl. 3, figs. 9−16). 5.2. the gârbova de jos/alsóorbó locality the 20 m high outcrop is located near the village of gârbova de jos (46°27’25.58”n, 24°17’10.57”e) (fig. 1). the outcropping succession is cut by a large normal fault of several metres offset, there fore a relatively thick sedimentary succession can be studied (fig. 3). it comprises clast-supported, graded conglomerates, thick pebb ly mudstones, mud-clast conglomerate, pebbly sandstones, and coarseto medium-grained and mediumto fine-grained grad ed sandstone beds intercalated with mudstones. individual beds are 1−50 cm thick. poor normal grading and planeto crosslamination were recognized. clast size occasionally attains 50 cm in diameter. these boulders are covered by horizontally laminated, deformed mudstone layers. higher up, mudstone with a few centimetre thick graded sandstone intercalations becomes dominant. the top of the fine-grained sandstones rarely contains small vertical burrows. these beds are the products of sandy-silty turbidity currents, gravelly-sandy turbidity currents, and debris flows. the latter indicates the proximity of the basin-margin slo pe. this interpretation is supported by the composition of the gravel, indicating the apuseni mts. as a source area. according to kréz sek et al. (2010), a shallow marine ramp supplied coarse clastics to the open shelf; the frequent, large-volume mass wasting events, however, may suggest a steeper slope, such as that of a fan-delta, and to deeper water, probably below the „shelf-edge”. the studied sample was collected from the lower part of the outcrop, from the dark grey suspension fall out mudstone, which also contained thin shells of deep-water bivalves (paradacna cf. lenzi, congeria sp.). the ostracod association is very poorly preserved with thin and translucent valves. in addition to the fragments, only 48 complete valves were observed in our material. the fauna includes amplocypris sp., candona (typhlocypris) sp., candona (propon­ toniella) sp. and hemicytheria folliculosa (fig. 8). except for the small and ornamented valves of h. folliculosa, which are well-preserved, the valves are damaged and broken. in general, ostracods with smooth, thin and elongated carapaces suggest a calm, relatively deep environment (danielopol, 1980; rundić, 2006). specimens of the littoral hemicytheria follicu­ losa were probably transported into this environment. 5.3. the gârboviţa / középorbó locality this 20 m high outcrop is situated on the right bank of the gâr bova stream valley, across from the village (46°16’51.66”n, 23°38’07.26”e) (fig. 1). the fossils of this outcrop were briefly treated by wanek & filipescu (1994); they mention fossil leaves of the tropical plant daphnogene, molluscs, and ostracods, the latter indicating the pannonian „c” zone of papp (1951). the outcrop exposes marl beds and mediumto very finegrained, graded, planar to cross-laminated sandstone layers of 5−10 cm thickness; the latter are interpreted as turbidites. the marl layers are dark in colour due to plant remains (organic matter) (fig. 4). the depositional setting can be best understood by comparing this outcrop with the previous one, where the same marls and sandstones crop out together with various types of conglomerate (krézsek, 2005). congeria partschi czjzek and melanopsis vindobonensis – molluscs that lived in shallow-water lacustrine environments – are common in the redeposited turbidite layers. the silty marl layers contain a rich sublittoral mollusc assemblage: paradacna cf. lenzi, lymnocardium cf. majeri (m. hörnes), lymnocar­ dium cf. otiophorum (brusina), congeria banatica, „gyrau­ lus” pon ticus (lőrenthey), micromelania sp. occur together with fish teeth and otoliths. our sample was taken from this deepwater marl facies. the ostracod assemblage from gârboviţa is abundant and diverse; 225 ostracod valves were picked from the dried material. the fauna includes the following species (fig. 8): amplocypris firmus krstić (pl. 1, figs. 15–19), a. matejici krstić (pl. 1, figs. 11–14), herpetocyprella auriculata (reuss), h. hiero­ glyphica, candona (caspiolla) praebalcanica (pl. 1, figs. 23, 24), c. (typhlocypris) trigonella, c. (caspiocypris) transilvanica, c. (propontoniella) sp., hemicytheria folliculosa (pl. 2, figs. 27–32), loxocorniculina hodonica (pl. 3, figs. 2, 3), and cyprideis sp. three fossil species of herpetocyprella have been recognis ed in the deposits of lake pannon, and they were previously assign ed to hungarocypris (danielopol et al., 2008b). a single extant representative of the genus, herpetocyprella mongolica daday, is endemic to lake issyk-kul, kyrgizistan, central asia. it lives together with recent thalassic and athalassic cyprideis torosa and tyrrhenocythere amnicola at salinity of 6‰ (bron stein, 1947; ricketts et al., 2001). other shallow-water forms, such as he­ mi cytheria, loxoconcha, and cyprideis, are subordinate in the sample (8, 6 and 3% of the total specimens, respectively). 5.4. the mihalţ/mihálcfalva locality the sampled outcrop, approximately 60−80 m high and 200−300 m long, is situated 1 km n of the village, along the road dj142l, on the left bank of the mureş river (46°10’35.05”n, 23°42’20.70”e) (figs. 1, 5). decimetre to metre thick, massive or laminated marl and calcareous marl comprise the sediment succession with some rare, thin, mediumto fine-grained sandstone intercalations. the marls are mostly suspension fall out deposits accumulated on the basin plain. thin-shelled deep-water molluscs, such as paradacna cf. lenzi, congeria banatica, congeria sp., undulotheca pancici, micromelania sp. are relatively common in the massive marl from which the sample for ostracods was collected. the material consists of 56 ostracod valves, including different indeterminate species of paratethyan candoninae, and loxo­ concha rhombovalis, hemicytheria folliculosa, and amnicythere miscere (krstić) (fig. 8; pl. 2, figs. 25, 26, pl. 3, fig. 1). smooth, thin and translucent valves of candona have the most significant role in the association, but they are unidentifiable g eologia c roatica kovács et al.: pannonian ostracods from the southwestern transylvanian basin 219 figure 6. tău. an erosional surface divides the outcrop into a lower unit, dominated by mudstones formed as levee to overbank deposits intercalated with rare overspilling thin-bedded turbidites, and an upper unit with the complex, migrational deep-water channel fill. white dot indicate sampling locations within the lower unit. figure 7. oarba de mureş, outcrop e. massive and bioturbated clay marls. white dot indicates sampling location. g eo lo gi a c ro at ic a geologia croatica 69/2220 figure 8. pie charts of species distribution in each sample (percentage of specimens in all specimens from 250 g sediment). g eologia c roatica kovács et al.: pannonian ostracods from the southwestern transylvanian basin 221 to species level due to their very poor preservation. the small and ornamented valves of the other taxa are well preserved. loxocon­ cha occurs in mesoto euhaline, littoral environments (morkhoven, 1963). numerous amnicythere species live in the littoral and sublittoral zones of the black and caspian seas at brackish salinity, but some species have been observed in freshwater bays and estuaries. amnicythere multituberculata (livental) lives today in the central and southern caspian basins at salinities of 11.5−13.5‰. it is missing in the northern caspian basin, where freshwater input from volga river effectively lowers salinity (schor nikov, 1964). the freshwater lake ohrid, however, also hosts some endemic species of the genus, such as amnicy­ there karamani (klie) (namiotko et al., 2012). 5.5. the tău/székástóhát locality the outcrop is almost 1 km wide, where a 12−15 m high continuous succession can be followed over a distance of 300 m. it occurs along road dc203 (46°5’20.14”n, 23°50’33.36”e) (fig. 1). the central part of the outcrop can be divided into two units (fig. 6). the lower unit consists of thin beds of mudstone intercalating with very thin, fineor medium-grained sandstone beds. this unit contains a deep-water mollusc association with para­ dacna cf. lenzi, p. cf. abichi (r. hörnes), lymnocardium sp., congeria czjzeki m. hörnes, c. sp., velutinopsis sp., undulo­ theca pancici, micromelania sp. the upper unit starts with a wide erosional scour and is composed up of thick, often amalgamated, massive beds of mediumto very coarse-grained, granular sandstone. rip-up mud clasts and water-escape structures are common. shallow and laterally stepping erosional surfaces are also characteristic. sand beds in both units are the products of turbidity currents. the lower unit dominated by mudstones was formed as levee to overbank deposits with rare overspilling thin-bedded turbidites. the upper sandstone represents a complex, laterally migrating deep-water channel fill (krézsek et al., 2010; tőkés, 2013) (fig. 5). as a whole, a major isolated channel-levee system in a deep, profundal environment can be reconstructed in the outcrop. two samples were taken for ostracods; one from the lower part and another from the upper part of the fine-grained overbank sediments (lower unit). the assemblage from the lower part of the marl unit is poorly preserved and consists of 88 ostracod valves (fig. 8). the fauna includes amplocypris sp., candona sp., hemicytheria folliculosa, h. reticulata (sokač) (pl. 2, fig. 24), and amnicythere sp. the assemblage from the upper part of the marl unit is poor in species and individuals (the sample consists of 57 ostracod valves; fig. 8). the fauna includes hemicytheria folliculosa, h. reticulata, amnicythere sp., and amplocypris sp. candona is rare in the lower sample and completely missing from the upper one. hemicytheria and amplocypris are dominant in the upper marl bed. amnicythere occurs in both samples, but it is more abundant in the upper one. hemicytheria, a representative of the littoral environment, indicates resedimentation processes. 5.6. the cunţa/konca locality the sampling location is about 1 km west of the village of cunţa at the western border of its administrative area (45°92’63.63”n, 23°70’21. 23”e) (fig. 1). lőrenthey (1893) published a list of molluscs from cunţa (at that time spelled as koncza), including melanopsis fossilis (gmelin), m. pygmaea hörnes, m. bouei férussac, plagiodacna carinata (deshayes), congeria sub globosa partsch, c. partschi, congeria sp., unio sp., and theodoxus crenulatus (klein). lőrenthey (1893) thought that this fauna represented the „lyrcaea-horizon”, the uppermost stratigraphic unit out of the three ones that he recognized in the transylvanian basin. the exact location where fossils of these shallow-water species were collected, however, remains unknown. the sampled outcrop displays decimetre to metre thick coarse-grained sandstone and pebbly sandstone beds, up to cobble-sized clasts. these are mostly well sorted with horizontal lamination. the sandstones alternate with bluish grey, bioturbated marls. some marl layers are laminated. fish remnants (otoliths, teeth) are common in the studied beds. gravity mass flows and suspension settling alternated in the depositional environment. three samples were collected from different levels of the bluish grey marl layers. the sample from the lower part of the outcrop consists of 154 well-preserved ostracod valves. the most frequent genera are amplocypris and herpetocyprella. the fauna includes the following species (fig. 8): amplocypris matejici, a. sp., herpeto­ cyprella auriculata (pl. 1, figs. 6–10), candona (thaminocypris) sp., c. (caspiocypris) sp., c. (propontoniella) sp., c. (typhlo­ cypris) trigonella, c. (lineocypris) sp., cypria sp. and loxocon­ cha rhombovalis (pl. 3, fig. 4). the ostracod fauna from the middle part of the outcrop comprises a rich and well-preserved association. we found 344 juvenile and adult ostracod valves, representing the following species: candona (lineocypris) dorsobrevis krstić (pl. 1, figs. 25–28), c. (caspiocypris) sp., c. (lineocypris) sp., c. (propontoniella) macra, c. (propontoniella) sp., c. (caspiocypris) transilvanica, c. (caspiolla) sp., c. (thaminocypris) sp., amplocypris sp., a. firmus, herpetocyprella auriculata, c. (caspiocypris) aspera (héjjas), and hemicytheria folliculosa (fig. 8). the ostracod fauna from the upper part of the cunţa outcrop is the richest and most diverse association in this study; we found 665 well-preserved ostracod valves in the material. the association includes amplocypris reticulata, a. matejici, herpetocyprel la hieroglyphica (pl. 1, figs. 1–5), candona (caspiocypris) transil­ vanica (pl. 2, figs. 5–8, 13–15), c. (propontoniella) macra (pl. 2, figs. 9–12), c. (caspiolla) sp., c. (caspiocypris) cf. aspera (pl. 2, figs. 1–4), c. (lineocypris) sp., c. (lineocypris) dorsobrevis, hemicytheria folliculosa, cypria pannonica (krstić) (pl. 2, figs. 20–23), cypria sp., and amnicythere sp. (fig. 8). the cunţa assemblages, especially from the middle and upper parts of the section, differ from our other samples in the diversity and dominance of various paratethyan candoninae species. in general, the majority of candona species are freshwater, tolerating a slight increase of salinity, but the endemic lake pannon candoninae adapted to brackish water (meisch, 2000; cziczer et al., 2008). typically trapezoid-shaped species of the subgenus lineocypris occur predominantly in the deep parts of large lakes (morkhoven, 1963). the appearance of cypria in both the lower and upper samples is also a unique feature of the cunţa outcrop. most species of cypria live in freshwater (lakes, pools) preferring environments with abundant vegetation, although they tolerate mesohaline conditions as well (meisch, 2000). the appearance of this genus therefore may indicate freshwater influence, probably proxi mity of a deltaic environment, in accord with the presence of unio in the cunţa mollusc fauna (lőrenthey, 1893). 5.7. the oarba de mureş/marosorbó locality the investigated outcrop is on the right bank of the river mureş near oarba de mureş village (46°27’25.58”n, 24°17’10.57”e) g eo lo gi a c ro at ic a geologia croatica 69/2222 (figs. 1, 7). the upper sarmatian to lower pannonian outcrops at oarba de mureş received much attention recently (sztanó et al., 2005; sütő-szentai & szegő, 2008; vasiliev et al., 2010; filipescu et al., 2011). the outcrop sampled (and designated as outcrop „e”) is located in the horizontal continuation of outcrop d of sztanó et al. (2005), exposing massive and bioturbated clay marl with up to 0.5−1 m thick beds, and with intercalations of a few cm thick calcareous marls (fig. 7). in this part of the succession sediments indicate deep basin-floor environment without mass-flow events. in one of the calcareous marl layers, molluscs („lymnocardium” undatum (reuss), congeria cf. banatica) were preserved as moulds. the sample was collected from a massive clay marl bed from the lower part of the outcrop. the investigated ostracod fauna, consisting of 100 valves, has low diversity (fig. 8). the assemblage includes the following brackish water ostracods: amplocypris sp., candona (caspio­ cypris) sp., c. (caspiolla) sp., c. (propontoniella) sp., c. (typh­ locypris) trigonella, and ilyocypris cf. expansa (reuss) (pl. 2, figs. 16–19). 11.6 ma ca. 9 ma pokorný, 1944 papp, 1951 kollmann, 1960 h jiřiček, 1985 slavonian substage pannonian age serbian substage regional chronostratigraphy krstić, 1985 h em ic yt he ria lő re nt he yi h em ic yt he ria hu ng ar ic a h em ic yt he ria te nu is tr ia ta pr op on to ni el la ca nd eo a m pl oc yp ris ab sc is sa h em ic yt he ria cr oa tic a se rb ie lla sa gi tt os a ty ph lo cy pr el la lin eo cy pr ifo rm is a b c d e f g e a b o st ra co d sp ec ie s amplocypris reticulata (héjjas, 1894) o st ra co d a b io zo n es α β γ δ amplocypris firmus krstić, 1973 ○ amplocypris matejici krstić, 1973 ● ● herpetocyprella auriculata (reuss, 1850) amlpocypris sp. ● ◦ ○ ● candona (typhlocypris) sp. candona (thaminocypris) sp. ● herpetocyprella hieroglyphica (méhes, 1907 ) ● candona (typhlocypris) trigonella (héjjas, 1894) ○ ◌ candona (caspiocypris) aspera (héjjas, 1894) ● ○ candona (caspiocypris) sp. ○ ◌ ● candona (caspiolla) praebalcanica (krstić, 1972) candona (caspiolla) sp. ○ ○ candona (propontoniella) sp. candona (propontoniella) macra (krstić, 1972) ◌ ◌ ◦ ○ candona (lineocyris) sp candona (lineocyris) dorsobrevis (krstić, 1972) ○ candona sp. hemicytheria folliculosa (reuss, 1850) ○ cyprideis pannonica (méhes, 1908) hemicytheria reticulata (sokač, 1972) ○ cyprideis sp. ◦ cypria pannonica (krstić, 1973) ○ ilyocypris cf. expansa (reuss, 1850) cypria sp. amnicythere sp. amnicythere miscere (krstić, 1973) ◌ ● loxoconcha rhombovalis (pokorný, 1952) loxocorniculina hodonica (pokorný, 1952) ◦ ◦ ○ outcrops ● > 26 ○ 13-25 ◌ 7-12 ◦ 1-6 specimens in 250 g dried material stratigraphic range of the species in literature data lo pa de a ve ch e g âr bo vi ța g âr bo va d e jo s m ih al ț o ar ba d e m ur eș tă u up pe r s am pl e tă u lo w er s am pl e cu nț a lo w er s am pl e cu nț a m id dl e sa m pl e cu nț a up pe r s am pl e candona (caspiocypris) transilvanica (héjjas, 1894) ○ ○ ○ ● c d e1 e2 e3 a b c d ● ● ○ ● ● ● ◌ ○ ◦ ● ● ◌ ○ ● ○ ◌ ◌ ◦ ○ ● ○ ● ● ● ● ● ● ○ ○ ● ● ◌ ◌ ◦ ◦ ◦ ● ○ ○ ○ ◦ ○ ◌ ○ table 1. occurrences of pannonian ostracod species in the investigated outcrops and the stratigraphic distribution of each species according to the literature (pokorný, 1944; krstić, 1971, 1972a, b, 1973a, b, 1985; sokač, 1972, 1990; jiřiček, 1985; wanek, 1992a; filipescu, 1996; rundić, 1998, 2006; rundić et al., 2011; filipescu et al., 2011). g eologia c roatica kovács et al.: pannonian ostracods from the southwestern transylvanian basin 223 the most common species in the assemblage belong to am­ plocypris and candona. their valves are thin, translucid and often broken. the oblong and elongated carapace shape may indicate benthic dwellers (de deckker, 2002). ilyocypris cf. expansa seems to be an exotic element in the assemblage, because ilyocypris is known to live in freshwater, tolerating slowly running water (meisch, 2000). valves of the modern species ilyocypris lacustris kaufmann, 1900 were recorded from freshwater lakes at depths of 35−139 m, but the presence of living specimens in deep water environment is uncertain (meisch, 2000). its presence in this deep-water assemblage is probably due to reworking from a shallow, freshwater-influenced environment. 6. discussion and conclusions 6.1. palaeoenvironment and palaeogeography the overall palaeoecological interpretation of the investigated ostracod faunas is difficult; probably much more samples would be required to understand the ecological significance of these endemic species. in general, the assemblages indicate a mixture of deep-water and shallow-water species. thin-shelled, smooth paratethyan candoninae occupied the sublittoral to profundal zones of lake pannon, from the wave base down to the foot of the slope. the littoral zone was inhabited by forms with thicker and ornamented shells, such as, for instance, cyprideis, loxoconcha, am­ nicythere, and hemicytheria. in our samples, the deep-water and littoral taxa occur in various ratio. interestingly, the mollusc fauna shows similar characteristics across some of the investigated outcrops (lopadea veche, gârbo viţa, and, according to the literature, cunţa). thin-shelled bival ves, known to be confined to deep water environments elsewhere (e.g. paradacna abichi, congeria banatica, undulotheca pancici), occur together (or in very close proximity to) typical littoral, herbivorous snails, such as melanopsis. sedimentological patterns in all the outcrops indicate various kinds of mass transport deposits, most commonly interpreted as turbidites. although the ostracod samples were taken from fine-grained, suspension fall-out sediments, reworking and re-deposition of littoral ostracod valves into the deep-water environment is the most plausible explanation for the mixed character of the ostracod (and mollusc) faunas. in this case, the actual ostracod assemblages from the investigated part of the tb highly depend on local taphonomic factors. alternatively, some species of the otherwise littoral ostracod genera may have adapted to living at greater depths; such examples are recorded from the caspian sea (boomer et al. 2005). in terms of the abundance and diversity of ostracods, these outcrops can be divided into two distinct groups: lopadea, gârboviţa, and cunţa (all the three samples) yielded more than 100 specimens (154 to 665) and at least 10 species (10 to 14), whereas gârbova de jos, mihalţ, tau (both samples), and oarba de mureş yielded consistently fewer specimens (48−100) and species (4−6) from the same amount of sediment (fig. 8). in addition, reworked littoral molluscs occur in the first group, but they were not observed in the second. the first group of outcrops lie closer to the basin margin, directly on the foothills of the apuseni mts, where as the second group is located in a more basinward position (although the distance between gârboviţa and gârbova de jos is only a few kilometres). we hypothesize that these differences in abundance and diversity of the ostracods reflect environmental differences, such as deeper water and/or decreasing levels of oxygen and nutrients, i.e. more distal environments towards the basin interior. in the caspian sea (a paratethyan remnant) which is the best modern analogue of lake pannon, boomer et al. (2005) reported a steep gradient in ostracod diversity with increasing water depth within the deep water realm. they found that the number of ostracod species decreased from 17 to 3 between 315 and 479 m. in addition, their samples showed that total specimen abundance declined exponentially with increasing water depth. we speculate that these patterns may be analogous with the diversity and abundance drop that we observed in our samples, although there are no means of estimating the absolute water depth in the early pannonian tb. 6.2. biostratigraphic interpretation and age various ostracod biostratigraphic systems have been erected in different parts of the pannonian basin system, but they usually reflect local characteristics and significantly differ from each other (e.g. pokorný, 1944; kollmann, 1960; sokač, 1972; krs tić, 1973a, b, 1985; jiřiček, 1985; rundić, 1998, 2002, 2006; rundić et al., 2011). ganić et al. (2010) and ter borgh et al. (2013) came to the conclusion that the „classical” lake pannon ostracod biozones are difficult to identify in the otherwise diverse and abundant ostracod record of the beočin claypit (fruška gora, serbia), which is roughly coeval with these transylvanian samples, possibly because earlier biostratigraphic research underestimated the role of palaeoecological conditions in the occurrence and distribution of ostracods. a similar view was expressed by olteanu (2011). as no special zonation for the tb has been currently produced, the biostratigraphic zonation of krstić (1971, 1972a, b, 1973a, b, 1985) and sokač (1972, 1990) originally elaborated for the southern parts of the pannonian basin is applied here. recent stratigraphic observations from the tb (wanek, 1992a; fi li pescu, 1996; filipescu et al., 2011) were also taken into account. for instance, wanek (1992b) found that amplocypris reti culata is probably an endemic species for the tb, and is present only in the „α phase” of pokorný (1944), corresponding to the lowermost pannonian, i.e. lower part of the slavonian substage; loxoconcha rhombovalis determines the final part of the slavonian substage; cyprideis pannonica appears in the uppermost sarmatian and is present in the „α phase” of the pannonian. krstić (1985) erected 8 stratigraphic ostracod zones for the pannonian stage: four zones in the older slavonian and four in the younger serbian substages. the four slavonian zones (from bottom to top) are the hemicytheria loerentheyi, hemicytheria hungarica, hemicytheria tenuistriata, and propontoniella candeo zones. characteristic species of the three latter zones from the present material include: hemicytheria hungarica zone: cyprideis pannonica, am­ plocypris reticulata, amnicythere miscere, herpetocyprella au­ riculata, candona (caspiocypris) transilvanica. hemicytheria tenuistriata zone: loxocorniculina hodonica, herpetocyprella auriculata, hemicytheria folliculosa, candona (typhlocypris) trigonella, c. (propontoniella) macra, c. (cas­ piocypris) transilvanica, ilyocypris cf. expansa. propontoniella candeo zone: candona (propontoniella) ma­ cra, c. (thaminocypris) sp., herpetocyprella hieroglyphica, he­ mi cytheria reticulata, loxoconcha rhombovalis. the appearance of hemicytheria reticulata in the latter biozone requires some discussion because sokač (1972) and olg eo lo gi a c ro at ic a geologia croatica 69/2224 plate 1. pannonian ostracod assemblages from the southwestern part of the tb. 1−5 herpetocyprella hieroglyphica (méhes), cunța; right valve (rv), internal lateral view (1), rv, external lateral view (2), left valve (lv), juvenile (juv.) (3), central muscle scars (4), pore canals on the ventral part of the rv (5). 6−10 herpetocyprella auriculata (reuss), cunța; lv, fragment (6), rv juv. (7), rv juv. (8), lv juv. (9), rv juv. (10). 11−14 amplocypris matejici krstić, gârbovița; lv (11), rv (12), rv (13), lv (14). 15-19 amplocypris firmus krstić, gârbovița; lv (15), rv (16), rv (17), rv (18), rv (19). 20−22 amplocypris cf. reticulata (héjjas), lopadea veche; lv (20), lv (21), rv (22). 23, 24 candona (caspiolla) praebalcanica krstić, gârbovița; carapace, lateral view of lv (23), carapace, lateral view of rv (24). 25−28 candona (lineocypris) dorsobrevis krstić, cunța; lv (25), carapace, lateral view of rv (26), lv (27), rv (28). 29−32 candona (typhlocypris) trigonella (héjjas), lopadea veche; carapace, lateral view of lv (29), carapace, lateral view of lv (30), carapace, lateral view of rv (31), carapace, lateral view of rv (32). g eologia c roatica kovács et al.: pannonian ostracods from the southwestern transylvanian basin 225 plate 2. pannonian ostracod assemblages from the southwestern part of the tb. 1−4 candona (caspiocypris) cf. aspera (héjjas), cunța; lv (1), rv (2), rv (3), lv (4). 5−8 candona (caspiocypris) transilvanica (héjjas), cunța; rv (5), rv (6), lv (7), rv (8). 9−12 candona (propontoniella) macra krstić, cunța; lv (9), rv (10), lv (11), rv (12). 13−15 candona (caspiocypris) transilvanica (héjjas), cunța; lv (13), rv (14), carapace, lateral view of rv (15). 16−19 ilyocypris cf. expansa (reuss), oarba de mureș; internal lateral view of rv (16), lv (17), rv (18), lv (19). 20−23 cypria pannonica krstić, cunța; lv (20), lv (21), rv (22), lv (23). 24 hemicytheria reticulata sokač, tău; lv. 25, 26 amnicythere miscere (krstić), mihalț; lv (25), lv (26). 27−32 hemicytheria folliculosa (reuss), gârbovița; lv juv. (27), rv juv. (28), lv juv. (29), rv juv. (30), lv juv. (31), lv juv (32). g eo lo gi a c ro at ic a geologia croatica 69/2226 plate 3. pannonian micropalaeontological assemblages from the southwestern part of the tb. 1 amnicythere miscere (krstić), mihalț; lv. 2, 3 loxocorniculina hodonica pokornỳ, gârbovița; lv (2), lv (3). 4 loxoconcha rhombovalis pokornỳ, cunța; rv. 5−8 cyprideis pannonica (méhes), lopadea veche; rv, internal lateral view (5), rv, external lateral view (6), lv (7), rv (8). 9−16 fish skeletal fragments; fish teeth, gârbovița (9−10), fish tooth, mihalț (11), fish teeth, cunța (12−13), fish teeth, lopadea veche (14, 16), fish squama, lopadea veche (15). g eologia c roatica kovács et al.: pannonian ostracods from the southwestern transylvanian basin 227 teanu (2011) claim that this species occurs only in the serbian substage „late pannonian”). indeed, the specimens presented here differ from the original description of sokač (1972) in lacking the sharp, high ventral rib and the pronounced posterioventral part. such differences in the expression of ornamentation have been extensively discussed (for more details see keen, 1982), and they can be related to ecological or genetic factors, especially in the brackish environment of lake pannon in which ecological conditions were highly variable (pipík, 1998). lake pannon is well known for its extensive intralacustrine evolution (e.g. geary, 1990; pipík 2007). this discovery of h. reticulata may represent an ancestor of h. reticulata in the sense of sokač (1972), but this relationship should be demonstrated by detailed morphometric and evolutionary study of the subfamily hemicytherinae in lake pannon. in conclusion, the three ostracod biozones above are represented in the samples from the southwestern part of the tb (table 1). lopadea veche and gârboviţa belongs to the hemicytheria hungarica zone. samples from gârbova de jos, oarba de mureş, and mihalţ can be assigned into the hemicytheria tenuistriata zone. finally, the ostracod fauna from tău and cunţa indicates the propontoniella candeo zone. all these zones belong to the lower pannonian slavonian substage, but the oldest pannonian ostracod biozone, the hemicytheria loerentheyi zone was not iden tified in any of the samples. this interpretation is roughly supported by the mollusc fauna. the age of the outcrops is thus approximately between 10 and 11.3 ma (cf. vasiliev et al., 2010). acknowledgment the authors thank ferenc wanek for discussions on the transylvanian ostracods, and dániel botka and csaba krézsek for the photo courtesy of the mihalţ and tau outcrops, respectively. ilaria mazzini (roma tre) kindly reviewed an earlier version of the manuscript. the reviewers of the present paper were valentina hajek-tadesse (croatian geological survey, zagreb) and ljupko rundić (university of belgrade); their careful reviews are acknowledged herein. this is mta-mtm-elte paleo contribution no. 220, partly funded by the hungarian national research, development and innovation office – nkfi 116618. references boomer, i. & eisenhauer, g. (2002): ostracod faunas as palaeoenvironmental indicators in marginal marine environments.− in: holmes, j.a. & chivas, a.r. (eds.): the ostracoda: applications in quaternary research. geophysical monograph series, 131, american geophysical union, washington dc, 135−149. doi: 10.1029/131gm07. boomer, i., grafenstein von, u., guichard, f. & bieda, s. (2005): modern and holocene sublittoral ostracod assemblages (crustacea) from the caspian sea: a unique brackish, deep-water environment.− palaeogeography, palaeoclimatology, palaeoecology, 225, 173−186. doi:10.1016/j.palaeo.2004.10.023. bronstein, z.s. (1947): fauna sssr. rakoobraznye, tom ii, vyp. 1. ostracoda presnykh vod. academy of sciences of the ussr publishers, moscow, 5–339. (english translation (1988): freshwater ostracoda− fauna of the ussr: crustaceans, vol. ii, no.1. aa balkema, rotterdam, 1–455). chintăuan, i. (1971): study of the ostracods from the neogene sediments from western part of munţii bârgăului.− studia universitatis babeş-bolyai, series geologia-mineralogia, 16, 71 p. ciulavu, d. (1999): tertiary tectonics of the transylvanian basin.− phd thesis, vrije universiteit, amsterdam, 152 p. clichici, o. (1980): cercetări geologice în perimetrul măgina-aiud-ciumburd (jud. alba) [geological research in area măgina-aiud-ciumburd (alba county) − in romanian].− studia universitatis babeş-bolyai, series geologia-geographia, 25, 21−32. cziczer, i., magyar, i., pipík, r., böhme, m., ćorić, s., bakrač, k., sütőszentai, m., lantos, m., babinszki, e. & müller, p. (2008): life in the sublittoral zone of long-lived lake pannon: paleontological analysis of the upper miocene szák formation, hungary.− international journal of earth sciences, 98, 1741−1766. doi: 10.1007/s00531-008-0322-3. danielopol, d. (1980): on the carapace shape of some european freshwater interstitial candoninae (ostracoda).− proceedings of the biological society of washington, 93, 743−756. danielopol, d.l., gross, m., piller, w.e. & baltanas, a. (2008a): ostracods of the paratethys sea and lake pannon – perspectives for renewal of cooperative projects.− senckenbergiana lethaea, 88, 141−145. doi: 10.1007/bf03043985. danielopol, d.l., buttinger, r., pipík, r., gross, m., olteanu, r. & knoblechner, j. (2008b): miocene “hungarocypris” species of lake pannon (central and south-eastern europe) transferred to herpetocyprella daday, 1909 (ostracoda, cyprididae).− senckenbergiana lethaea, 88, 147−160. doi: 10.1007/ bf03043986. de broucker, g., mellin, a. & duindam, p. (1998): tectonostratigraphic evolution of the transylvanian basin, pre-salt sequence, romania.− in: dinu, c. & mocanu, v. (eds.): geological and hydrocarbon potential of the romanian areas, bucharest geosciences forum, 1, 36−70. de deckker, p. (2002): ostracod palaeoecology.− in: holmes, j.a. & chivas, a.r. (eds.): the ostracoda: applicatons in quaternary research. geophysical monograph series, 131, american geophysical union, washington dc, 121−134. doi: 10.1029/131gm06. de leeuw, a., filipescu, s., matenco, l., krijgsman, w., kuiper, k. & stoica, m. (2013): paleomagnetic and chronostratigraphic constraints on the middle to late miocene evolution of the transylvanian basin (romania): implications for central paratethys stratigraphy and emplacement of the tisza-dacia plate.− global and planetary change, 103, 82−98. doi:10.1016/j.gloplacha.2012.04.008. filipescu, s. (1996): stratigraphy of the neogene from the western border of the transylvanian basin.− studia universitatis babeş-bolyai, series geologia, 41, 3−69. filipescu, s. (1999): the significance of foraminifera fauna from the feleac formation (transylvanian basin, romania).− studia universitatis babeş-bolyai, series geologia, 44, 125–131. filipescu, s., wanek, f., miclea, a., de leeuw, a. & vasiliev, i. (2011): micropaleontological response to the changing paleoenvironment across the sarmatian-pannonian boundary in the transylvanian basin (miocene, oarba de mureş section, romania).− geologica carpathica, 62, 91−102. doi: 10.2478/v10096-0110008-9. ganić, m., rundić, l., knežević, s., cvetkov, v. (2010): the upper miocene lake pannon marl from the filijala open pit (beocin, northern serbia): new geological and paleomagnetic data.− geološki anali balkanskoga poluostrva, 71, 95−108. doi: 10.2298/gabp1071095g. garcia-castellanos, d. (2006): long-term evolution of tectonic lakes: climatic controls on the development of internally drained basins.− in: willett, s.d., hovius, n., brandon, m.t. & fisher, d.m. (eds.): tectonics, climate, and landscape evolution. geological society of america special paper, 398, 283−294. doi: 10.1130/2006.2398(17) . geary, d.h. (1990): patterns of evolutionary tempo and mode in the radiation of melanopsis (gastropoda; melanopsidae). paleobiology,− 16, 492−511. doi: 10.1017/s0094837300010216. ghergari, l., mészáros, n., hosu, a., filipescu, s. & chira, c. (1991): the gypsiferous formation at cheia (cluj county).− studia universitatis babeşbolyai, series geologia, 36, 13−28. gillet, s. (1943): les limnocardiides des couches á congéries de roumanie.− memoriile institutului geologic al româniei, 4, 1−114. harzhauser, m. & mandic, o. (2008): neogene lake systems of central and south-east europe: faunal diversity, gradients and interrelations.− palaeogeography, palaeoclimatology, palaeoecology, 260, 417−434. doi:10.1016/j.palaeo.2007.12.013. harzhauser, m., kern, a., soliman, a., minati, k., piller, w.e., danielopol, d.l. & zuschin, m. (2008): centennialto decadal-scale environmental shifts in and around lake pannon related to a major late miocene lakelevel rise.− palaeogeography, palaeoclimatology, palaeoecology, 270, 102−115. doi:10.1016/j.palaeo.2008.09.003. héjjas, i. (1894): új adatok erdély fossil ostracoda-faunájához [new data on the fossil ostracod fauna of transylvania – in hungarian].– orvostermészettudományi értesítő, ii. természettudományi szak, kolozsvár, 16, 35−68. holmes, j.a. (2001): ostracoda− in: smol, j. p., birks, h.j. & last, h.j.b. (eds.): tracking environmental change using lake sediments zoological indicators, 4, kluwer academic publisher, dordrecht, 125−151. doi: 10.1007/0-306-47671-1. ilie, m. (1952): cercetări geologice în regiunea cluj-cojocna-turda-ocna mureşuluiaiud [geological research in cluj-cojocna-turda-ocna mureşului-aiud region − in romanian].− anuarul comitetului geologic, 24, 303−369. jiřiček, r. (1985): die ostracoden des pannonien.– in: papp, a., jámbor, á. & steininger, f.f. (eds.): chronostratigraphie und neostratotypen, miozän der zentralen paratethys 7, pannonien. akadémiai kiadó, budapest, 378–425. g eo lo gi a c ro at ic a geologia croatica 69/2228 keen, m.c. (1982): intraspecific variation in tertiary ostracods.– in: bate, r.h., robinson, e. & sheppard, l.m. (eds.): fossil and recent ostracods. ellis horwood limited, chichester, 381–405. koch, a. (1900): die tertiärbildungen des beckens des siebenbürgischen landestheile, ii. neogene abtheilung.− budapest, 369 p. kollmann, k. (1960): cytherideinae und schulerideinae n. subfam. (ostracoda) aus dem neogen des östl. oesterreich.– mitteilungen der österreichischen geologischen gesellschaft in wien, 51, 89−195. korecz, a. (1991): a dk-dunántúli pannóniai s.l. ostracoda fauna vizsgálatának eredményei [the pannonian s.l. ostracod fauna from se transdanubia – in hungarian].– phd thesis, eötvös loránd university, department of paleontology, budapest, 231 p. kováč, m., andreyeva-grigorovich, a., bajraktarević, z., brzobohatý, r., filipescu, s., fodor, l., harzhauser, m., nagymarosy, a., oszczypko, n., pavelić, d., rögl, f., saftić, b., sliva, ľ. & studencka, b. (2007): badenian evolution of the central paratethys sea: paleogeography, climate and eustatic sea-level changes.– geologica carpathica, 58, 579–606. krézsek, c. (2005): sedimentologia şi arhitectura depozitelor pannoniene din estul bazinului transilvaniei [sedimentology and architecture of the pannonian sedi­ ments in the eastern transylvanian basin − in romanian].– phd thesis, babeşbolyai university, faculty of biology and geology, cluj-napoca, 165 p. krézsek, c. & bally, a.w. (2006): the transylvanian basin (romania) and its relation to the carpathian fold and thrust belt: insights in gravitational salt tectonics.– marine and petroleum geology, 23, 405–442. doi:10.1016/j.marpetgeo.2006.03.003 krézsek, c. & filipescu, s. (2005): middle to late miocene sequence stratigraphy of the transylvanian basin (romania).– tectonophysics, 410, 437–463. doi:10.1016/j.tecto.2005.02.018. krézsek, c., filipescu, s., silye, l., maţenco, l. & doust, h. (2010): miocene facies associations and sedimentary evolution of the southern transylvanian basin (romania): implications for hydrocarbon exploration.– marine and petroleum geology, 27, 191–214. doi:10.1016/j.marpetgeo.2009.07.009. krstić, n. (1971): ostrakodi kongerijskih slojeva: 9. cytherura, cytherissa, limno­ cythere i loxocauda [ostracodes des couches congériennes: 9. cytherura, cytherissa, limnocythere et loxocauda – in serbian with french summary].– glasnik prirodnjačkog muzeja, serija a, beograd, 26, 143–185. krstić, n. (1972a): rod candona (ostracoda) iz kongerijskih slojeva južnog dela panonskog basena [genus candona (ostracoda) from congeria beds of southern pannonian basin − in serbian with english summary].– the serbian academy of sciences and arts, monographs, 450, the section of natural and mathematical sciences, beograd, 39, 145 p. krstić, n. (1972b): ostrakodi kongerijskih slojeva: 10. loxoconcha [ostracods from the congerian beds: 10. loxoconcha – in serbian with english summary].– glasnik prirodnjačkog muzeja, serija a, beograd, 27, 243–275. krstić, n. (1973a): biostratigrafija kongerijskih slojeva okoline beograda na osnovu ostrakoda sa opisom vrsta roda amplocypris [biostratigraphy of the congerian beds in the belgrade region on the basis of ostracoda − in serbian with english summary].– institute for geological and mining exploration and investigation of nuclear and other mineral raw materials, monographs, 4, 158 p. krstić, n. (1973b): ostrakodi kongerijskih slojeva 11: amnicythere [ostracoda from the congerian beds: 11. amnicythere – in serbian with english summary].– radovi igri, 8, beograd, 53–99. krstić, n. (1985): ostracoden im pannonien der umgebung von belgrad.– in: papp, a., jámbor, á. & steininger, f.f. (eds.): chronostratigraphie und neostratotypen, miozän der zentralen paratethys 7, pannonien. akadémiai kiadó, budapest, 103–144. krstić, n. & stancheva, m. (1990): ostracod of eastern serbia and northern bulgaria with notices on a northern turkey assemblage and some mediterranean assemblages.– in: stevanovič, p., nevesskaja, l.a., marinescu, fl., sokač, a. & jámbor, á. (eds.): chronostratigraphie und neostratotypen: neogen der westlichen (’’zentrale’’) paratethys 8. pontien (1989). jazu and sanu, zagreb-beograd, 753–819. lőrenthey, i. (1893): adatok szilágymegye és az erdélyi részek alsó pontusi lerakódásainak ismeretéhez. ii. az erdélyi-medencze alsó pontusi képződményeinek faunája [data for the lower pontian sediments in salaj county and partium. ii. fauna of the lower pontian sediments from transylvania – in hungarian].– orvostermészettudományi értesítő, ii. természettudományi szak, kolozsvár, 15, 213–230. lubenescu, v. & lubenescu, d. (1976): observaţii biostratigrafice asupra pannonianului de la lopadea veche (depresiunea transilvaniei) [biostratigraphical observations on the pannonian from lopadea veche (transylvanian depression) – in romanian].– dări de seamă ale şedinţelor, 63, 57–64. magyar, i., geary, h.d. & müller, p. (1999): paleogeographic evolution of the late miocene lake pannon in central europe.– palaeogeography, palaeoclimatology, palaeoecology, 147, 151–167. doi:10.1016/s0031-0182(98)00155-2. maţenco, l., krézsek, cs., merten, s., schmid, s.m., cloetingh, s. & adriessen, p. (2010): characteristics of collisional orogens with low topographic build-up: an example from the carpathians.– terra nova, 22, 155–165. doi: 10.1111/j.1365-3121.2010.00931.x. meisch, c. (2000): freshwater ostracoda of western and central europe.– spektrum akademischer verlag, heidelberg–berlin, 522 p. morkhoven, van f.p.c.m. (1963): post-paleozoic ostracoda, their morphology, taxonomy and economic use, part 2.– elsevier, new york, 478 p. doi: 10.2108/ zsj.26.846. müller, p., geary, d.h. & magyar, i. (1999): the endemic molluscs of the late miocene lake pannon: their origin, evolution, and family-level taxonomy.– lethaia, 32, 47–60. doi: 10.1111/j.1502-3931.1999.tb00580.x. namiotko, t., danielopol, d.l., belmecheri, s., gross, m. & von grafenstein, u. (2012): on the leptocytheridae ostracods of the long-lived lake ohrid: a reappraisal of their taxonomic assignment and biogeographic origin.– international review of hydrobiology, 97, 356–374. doi: 10.1002/iroh.201211496. olteanu, r. (2011): atlas of the pannonian and pontian ostracods from the eastern area of the pannonian basin. geo-eco-marina 17, 135–177. papp, a. (1951): das pannon des wiener beckens.– mitteilungen der geologischen gesellschaft in wien, 39–41, 99–193. papp a., jámbor á. & steininger f. (eds.) (1985): chronostratigraphie und neostratotypen, miozän der zentralen paratethys 7, pannonien. akadémiai kiadó, budapest, 636 p. paulissen, w., luthi, s.m., grunert, p., ćorić, s. & harzhauser, m. (2011): integrated high-resolution stratigraphy of a middle to late miocene sedimentary sequence in the central part of the vienna basin.– geologica carpathica, 62, 155–169. doi: 10.2478/v10096-011-0013-z. pávay-vajna, f. (1910): die geologischen verhältnisse der umgebung von olah-lapad.– földtani közlöny, 40, 420–434. pipík, r. (1998): salinity changes recorded by ostracoda assemblages found in pannonian sediments in the western margin of the danube basin.– bulletin des centres de recherches exploration-production elf-aquitaine, pau, mém. 20, 167–177. pipík, r. (2007): phylogeny, palaeoecology, and invasion of non-marine waters by the late miocene hemicytherid ostracod tyrrhenocythere from lake pannon.– acta palaeontologica polonica, 52, 351–368. pipík, r. & bodergat, a.m. (2004): euxinocythere (ostracoda, cytheridae, leptocytherinae) du miocène supérieur du basin de turiec (slovaquie): taxonomie et paléoécologie.– revue de micropaleontologie, 47, 36–52. doi:10.1016/j.revmic.2004.01.001. pokorný, v. (1944): la microstratigraphie du pannonien entre hodonin et mikulcice (moravie meridionale, tchecoslovaquie).– bull. inter. acad. tcheque. sci., 23, 1–25. popescu, b.m. (1995): romania’s petroleum systems and their remaining potential.– petroleum geociences, 1, 337–350. doi: 10.1144/petgeo.1.4.337. reuss, a.e. (1850): die fossile entomostraceen des österreichischen tertiärbeckens.– naturwissenschaftliche abhandlungen, wien, 2/1, 41–92. royden, l.h. (1988): the pannonian basin: a study in basin evolution. – american association of petroleum geologists, memoir, 45, 17– 25. ricketts, r.d., johnson, th.c., brown, e.t., rasmussen, k.a. & romanovsky, v.v. (2001): the holocene paleolimnology of lake issyk-kul, kyrgyzstan: trace element and stable isotope composition of ostracodes.– palaeogeography, palaeoclimatology, palaeoecology, 176, 207–227. doi: 10.1016/ s0031-0182(01)00339-x. rundić, lj. (1998): the carapace of fossil ostracodes: paleoenvironmental indicators.– geološki anali balkanskoga poluostrva, 64, 137–151. rundić, lj. (2002): some species of the genus hemicytheria, pokorny (ostracoda, crustacea) from the upper miocene of serbia.– annales géologiques de la péninsule balkanique, 64, 137–151. doi:10.2298/gabp0264137r. rundić, lj. (2006): late miocene ostracodes of serbia: morphologic and palaeoenvironmental considerations.– geološki anali balkanskoga poluostrva, 67, 89–100. doi: 0350-0608/2006/0350-06080667089r. rundić, lj., ganić, m., knežević, sl. & soliman, a. (2011): upper miocene pannonian sediments from belgrade (serbia): new evidence and paleoenvironmental considerations.– geologica carpathica, 62, 267–278. doi: 10.2478/v10096011-0021-z sanders, c.a.e., andriessen, p. & cloetingh, s. (1999): life cycle of the east carpathian orogen: erosion history of a doubly vergent critical wedge assessed by fission track thermochronology.– journal of geophysical research, 104 (b12), 29, 1–112. doi: 10.1029/1998jb900046. schmid, s.m., bernoulli, d., fügenschuh, b., maţenco, l., schefer, s., schuster, r., tischler, m. & ustaszewski, k. (2008): the alpinecarpathian-dinaridic orogenic system: correlation and evolution of tectonic units.– swiss journal of geosciences, 101, 139–183. doi: 10.1007/s00015-008-1247-3. g eologia c roatica kovács et al.: pannonian ostracods from the southwestern transylvanian basin 229 schornikov, e.i. (1964): an experiment on the distinction of the caspian elements of the ostracod fauna in the azov-black sea basin.– zoologitcheskii zhournal, 43, 1276–1293. sokač, a. (1972): pannonian and pontian ostracode fauna of the mt. medvednica.– paleontologia jugoslavica, 11, 1–140. sokač, a. (1990): pontian ostracod fauna in the pannonian basin – in: stevanović, p.m., nevesskaya, l.a., marinescu, f., sokač, a. & jámbor, á. (eds.): chronostratigraphie und neostratotypen, neogen der westlichen (‘‘zentrale’’) paratethys 8, pontien. jazu and sanu, zagreb–beograd, 672–721. stevanović, p.m., nevesskaya, l.a., marinescu, f., sokač, a. & jámbor á. (eds.) (1990): chronostratigraphie und neostratotypen, neogen der westlichen (“zentrale”) paratethys 8, pontien. jazu and sanu, zagreb-beograd, 952 p. sütő-szentai, m. & szegő, é. (2008): organic-walled microplankton studies from beds of the sarmatian-pannonian stratotype section at marosorbó (oarba de mureş), transylvanian basin.– földtani közlöny, 138, 279–296. sztanó, o., krézsek, cs., magyar, i., wanek, f. & juhász, gy. (2005): sedimentary cycles and rhythms in a sarmatian to pannonian (late miocene) transitional section at oarba de mureş / marosorbó, transylvanian basin.– acta geologica hungarica, 48, 235–257. doi: 10.1556/ageol.48.2005.3.1 ter borgh, m., vasiliev, i., stoica, m., knežević, s, maţenco, l., krijgsman, w., rundić, l. & cloetingh, s. (2013): the isolation of the pannonian basin (central paratethys): new constraints from magnetostratigraphy and biostratigraphy.– global and planetary change, 103, 99–118. doi:10.1016/j. gloplacha.2012.10.001. tőkés, l.b. (2013): pannon-tavi turbiditek dél-erdélyi feltárásokban: szedimentológiai és gamma szelvényezés eredményei [the results of sedimentological and gamma­ ray logging of upper miocene lacustrine turbidites of the transylvanian basin – in hungarian].– msc thesis, eötvös loránd university, department of geology, budapest, 90 p. vasiliev, i., de leeuw, a., filipescu, s., krijgsman, w., kuiper, k., stoica, m. & briceag, a. (2010): the age of the sarmatian–pannonian transition in the transylvanian basin (central paratethys).– palaeogeography, palaeoclimatology, palaeoecology, 297, 54–69. doi:10.1016/j.palaeo.2010.07.015. wagner, c.w. (1964): ostracods as environmental indicators to recent and subrecent estuarine deposits of the netherlands.– in: puri, s. (ed.): ostracoda as ecological and paleoecological indicators. publicazioni della stazione zoologica di napoli, 33, 480–495. wanek, f. (1992a): kagylósrák-faunák az erdélyi-medence felső neogén üledékeiben [ostracod faunas in the upper neogene sediments of the transylvanian basin – in hungarian].– erdélyi múzeum-egyesület természettudományi és matematikai szakosztályának közleményei, 1, 93–98. wanek, f. (1992b): biostratigrafia ostracodelor sarmaţiene şi pannoniene din bazinul transylvaniei [biostratigraphy of sarmatian and pannonian ostracods in the transylvanian basin – in romanian].– raport bbu, arhiva romgaz, manuscript, 49 p. wanek, f. & filipescu, s. (1994): o fauna cu ostracode din pannonianul inferior de la moldovenesti [a fauna with ostracods from the lower pannnonian of mo­ ldoveneşti – in romanian].– symposium “75 ani de la infiinarea universitatii daciei superioare, cluj-napoca” programme & abstracts. www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction pedo-sedimentary successions refer to the vertical sequences of sedimentary deposits and associated palaeosol horizons that have been altered by pedogenic processes (retallack, 2019). these successions result from the interaction between sedimentation and soil development over time. the study of pedo-sedimentary successions is widely used to obtain informa tion on various aspects of earth history (retallack, 2019), e.g., palaeoenvironmental and geomorphological changes, material transport and palaeoclimatic interpretations and reconstructions (durn, 1996; correggiari et al., 1996; durn et al., 1999, 2018a, 2021; siart et al., 2010; wacha & frechen, 2011; galović, 2014; újvári et al., 2016; zerboni et al., 2015; sprafke et al., 2020; molnár et al., 2021; pfaffner et al., 2024; beerten et al., 2025, in press). when studying the loess-palaeosol sequence of susak island, wacha et al. (2011) found that the northern adriatic region represents a distinct and unique periglacial environment and should not be neglected in the study of global glacialinterglacial evolution. zerboni et al. (2015) investi gated the effects of soil formation processes under different environmental conditions and found that the different stages of pedogenesis can be linked to the overall progressive cooling during the last glacial cycle. durn et al. (2018b) investigated the polygenetic deciphering the pedo-sedimentary complex of the eastern adriatic coast: a case study from privlaka, croatia stanko ružičić1, lidija galović2, koen beerten3, nina hećej2,4, jasmina martinčević lazar2, rodoljub gajić5, stjepan husnjak6, rosa maria poch7, mihajlo pandurov5, petar stejić5, ajka pjanić2,* 1 university of zagreb faculty of mining, geology and petroleum engineering, croatia 2 croatian geological survey, zagreb, croatia; (*corresponding author: apjanic@hgi-cgs.hr) 3 belgian nuclear research centre sck cen, mol, belgium 4 university of bergen, department of earth science, bergen, norway 5 geological survey of serbia, belgrade, serbia 6 university of zagreb, faculty of agriculture, croatia 7 departament de química, física y ciències ambientals y del sòl, universitat de lleida, catalonia, spain doi: 10.4154/gc.2025.14 abstract this study provides the first analysis of the quaternary pedo-sedimentary complex to understand the succession of palaeosol and sediments, the mechanism of deposition, and the source and age of the material. each distinctive layer was sampled. palaeosols are rich in fine-grained components, predominantly silt. quartz dominates in the light mineral fraction, suggesting that the sediments underwent more redeposition than for typical continental loess. the increase in weathered quartz grains with increasing depth could indicate that the proportion of fluvial sediments has increased compared to the aeolian sediments. mineralogical and petrographic analyses confirmed the presence of chromite, serpentinite, and serpentinized olivine basalt, indicating an area of origin with ultramafic rocks, which could be the dinaric ophiolitic zone in the hinterland. the carbonates are polygenetic in origin and consist of equal parts of highly spherical upper cretaceous rudist limestones, eocene nummulitic limestones, and low spherical pedogenic carbonate concretions, indicating local transport. according to the osl dating results, the glacio-fluvial material is either early weichselian or saalian in age, while the palaeosol most likely cannot be younger than the eemian and may even have a middle pleistocene age. soils that formed on the loess accumulated during the late glacial. the authors found that the studied polygenetic profile on susak island developed from the late glacial to the holocene through both normal pedogenesis and erosion/sedimentation-induced pedogenesis. recently, banak et al. (2021) investigated the understanding of deposi tional mechanisms and palaeoclimatic conditions during the pleistocene in the central part of the eastern adriatic coast. the authors identified and described three different facies that formed during colder and warmer climatic conditions. they concluded that the siliciclastic material most likely originated from the eocene sandstones of the flysch basins in dalmatia, which were transported by wind and currents. galović et al. (2023) investigated sands and intrafor­ mational palaeosol in the continental part of croatia. the authors identified a previously unrecognized regional climatic period that interrupted the aeolian deposition. in addition, molnár et al. (2021) carried out a sedimentological recon­ struction of two eastern croatian loess-palaeosol sequences (zmajevac and šarengrad ii) located on the right bank of the danube river. in zmajevac, the sedimentological data indicated the increased proportion of sand in the sampled partial se quences, which could indicate a higher wind speed during accumulation. galović et al. (2011) investigated the geochemical com­ 2025 | 78/3 | 221–241 | 12 figs. | 9 tabs. | article history: manuscript received: march 10, 2025 revised manuscript accepted: july 8, 2025 available online: september 25, 2025 keywords: palaeosol, sediment, glacio-fluvial transport, dinaric ophiolitic zone, quaternary, osl g eo lo gi a c ro at ic a 222 geologia croatica 78/3 position and magnetic susceptibility (ms) to correlate these parameters with the sedimentological data of the upper pleistocene loess/palaeosol sedimentary succession in šarengrad, croatia. the authors concluded that the correlation between geochemical composition and magnetic susceptibility is primarily a function of pedogenesis. in addition, banak et al. (2013) investigated loess/palaeosol profiles in baranja. the authors found that, with few exceptions, the loess from baranja is very similar to loess deposits from other pannonian regions. the subject of this study is the pedo-sedimentary succession of privlaka (eastern adriatic coast, croatia), which represents a promising archive for paleoenvironmental changes, as it shows a clear alternation of palaeosol and (glacio­) fluvial deposits. the aim of this study is to describe the palaeosol and sediments and to define the area of origin for the development of the privlaka pedo-sedimentary succession. to achieve this goal, mineralogical, sedimentological and physico-chemical analyses were carried out. in addition, the age of the complex is determined using optically stimulated luminescence (osl) dating. 1.1. study area the wider research area (fig. 1) consists of upper cretaceous deposits (k22 and k23), rudist limestones of the turonian and senonian periods, which formed in a quiet littoral to neritic environment (majcen et al., 1970; majcen & korolija, 1973; banak et al., 2021). the carbonate and clastic deposits from the eocene (e12 and e23) transgressively overlie the deposits mentioned above. the lower eocene is represented by highly fossiliferous foraminiferal limestones formed in a littoral environment (majcen et al., 1970; majcen & korolija, 1973; ilijanić et al., 2018). the clastic deposits of the middle and upper eocene comprise the complex of deposits that continuously overlie the foraminiferal limestones. they consist of alternating marl and sandstone, and in the upper parts, conglomerates. this is the youngest preserved member of the continuous succession of palaeogene deposits, which are covered by quaternary deposits. the quaternary deposits of the studied area are represented by upper pleistocene deposits: sands, sandy clays (q13) and terra rossa (ts) (fig. 1). figure 1. location of the privlaka pedo-sedimentary succession. a geographical setting of the investigated succession (google maps, 2025); b the geological setting of the wider privlaka area (modified after majcen et al., 1970; majcen & korolija, 1973). the location of the investigated profiles is marked with a pink circle. https://www.google.com/maps/place/croatia/@44.23455,15.7881617,525170m/data=!3m1!1e3!4m6!3m5!1s0x133441080add95ed:0xa0f3c024e1661b7f!8m2!3d45.1!4d15.2000001!16zl20vmdfwajc?entry=ttu g eologia c roatica 223ružičić et al.: deciphering the pedo-sedimentary complex of the eastern adriatic coast: a case study from privlaka, croatia the composition of the deposits is determined by the palaeorelief of the underlying deposits and by the uneven dynamics of the depositional environment. various factors, such as wind, seepage water, or hydrodynamic conditions in partially enclosed or occasionally flooded waters, could have been in­ volved in the formation of such deposits. such variable dynamics of the depositional environment can also be associated with changing climatic conditions. intense relief erosion is correlated to the glacial period, while carbonate concretions are related to dry and semi­arid climates (majcen & korolija, 1973). the youngest quaternary deposits are re­ presented by lakes and ponds (j), diluvial (d), and alluvial (al) deposits. 2. materials and methods 2.1. fieldwork the privlaka pedo­sedimentary complex (44° 15.98062' n, 15° 7.2409' e, wgs 84) is located about one kilometre northwest of the center of privlaka. the complex has a total thickness of eight metres, but the upper two metres were not accessible. a field investigation was carried out in 2022. the field campaign began with the mechanical opening of a 0.5 to 1 m deep trench (pn1­5) in a six metre long profile within a pedo­sedimentary complex (fig. 2). the six metre long succession of profile pn1-5 was described in sedimentological and pedological detail. in order to carry out a high-resolution investigation of the succession, the profile was sampled up to six metres for sedimentological and mineralogical analyzes. 2.2. laboratory analyses 2.2.1. grain size and morphological analysis of the grains particle size analysis was performed on 21 samples in the croa tian geological survey (hgi-cgs) laboratory using the sieving and pipette methods. the shape of the grains (sphericity and roundness) was analyzed for the fractions 1 – 0.5, 0.5 – 0.25, 0.25 – 0.125, 0.125 – 0.09, and 0.09 – 0.045 mm to recon­ struct their transport history. sphericity and roundness were estimated using the graphical table of krumbein & sloss (1963). 2.2.2. physico-chemical properties the carbonate content was determined for 13 samples using the scm1 calcimeter (behr labor­technik, 2017) ac­ cord ing to scheibler's method. the carbonates were dissolved using hydrochloric acid (c(hcl) = 4 mol/l). the method was calibrated with pure caco3. the ph value (h2o) was determined according to hrn iso 10390 (2005). the proportion of organic matter (%) was determined gravimetrically. porcelain pots were annealed at a temperature of 450 °c, filled with figure 2. the pedo-sedimentary complex of privlaka, profile a units of the pedo-sedimentary complex; b palaeosol(s) (ps)/glacio-fluvial (gf) erosion boundary with distinctive features; c detailed graphical log of the profile pn1-5 with marked horizons/layers. g eo lo gi a c ro at ic a 224 geologia croatica 78/3 sample material weighing at least 0.5 g, and left in the oven at 110 °c overnight. the samples were then submerged in a 30% hydrogen peroxide solution in an amount sufficient to cover the entire sample. the sample was then annealed at 450 °c for 6 hours. the cooled samples were weighed, and the organic matter was calculated accordingly. the soil colour was determined in wet and dry conditions using the munsell soil colour charts (2013). 2.2.3. mineralogical properties mineralogical analysis using x­ray diffraction on powder sam­ ples was carried out in the hgi-cgs laboratory. qualitative and semi-quantitative mineralogical analyzes were carried out on a total of 13 bulk samples using a panalytical x'pert powder x­ray diffractometer. the radiation source of the de­ vice is a copper tube that emits cukα radiation with a wave­ length of λ=1.54 å. the diffractometer is equipped with a vertical θ­θ goniometer, a sample holder, an optical module to control the incident and diffracted radiation, a monochromator and a pixcel detector. the x­ray diffractometer is controlled by the "x'pert quantify" software, while the diffraction patterns were analyzed using the x'pert highscore plus software package, which is linked to an iccd database of all known mineral species (pdf­4/minerals, 2024). x­rays are gene­ rated at a voltage of 45 kv and a current of 40 ma. due to the higher proportion of carbonates in the samples and to obtain a clear diffraction pattern of them, the insoluble residue was also analyzed. the insoluble residue was obtained by dissolving the carbonates with a buffered solution (ph 5) of sodium acetate and acetic acid according to the procedure described in shang & zelazny (2008). semi-quantitative mineralogical analysis of the bulk samples was performed using the rietveld method, in which the standard mineral profiles identified in the sample are refined with the profile obtained from the recorded data. the interpretation of the diffraction patterns and the refinement pro cess were carried out using the x'pert highscore plus soft­ ware package, which is linked to a database of all known minerals and their structural, chemical and crystallographic data required for semi-quantitative analysis. the accuracy of the obtained results may vary from the actual values within a range of ± 3 – 5%. 2.2.4. modal analysis to determine the qualitative and semi-quantitative mineral com position of heavy and light mineral assemblages, 21 sam ples from pedogenetic and glacio­fluvial horizons were analyzed. after disaggregation in an ultrasonic bath and sieving to the size fraction 0.09 – 0.125 mm, the calcite was dissolved. this fraction was selected for analysis as it contains all virtual mineral types in a ratio representative of the bulk sample. the heavy mineral fraction (hmf) was separated using sodium polytungstate (spt) (ρ = 2.8 g cm­3). the slides of the heavy and light mineral fraction (lmf) were examined with the axiolab.a1 polarizing microscope from carl zeiss. the qualitative and semi-quantitative composition of a sample was determined after identifying 300 – 400 grains and calculating the percentage of each mineral. canada balsam was used as the embedding medium. the weathering index (w.i.) was used to investigate the degree of alteration of the analyzed horizons. the w.i. was defined by brewer (1976) and applied by faivre et al. (2019) and galović et al. (2023) as the ratio of the pro por­ tions of resistant and non-resistant minerals: w.i. = (zrn + tur + rt + ttn + st + grt) / (ep-zo + amp + px + ky). symbology is according to warr (2021): zrn – zircon, tur – tourmaline, rt – rutile, ttn – titanite, st – staurolite, grt – garnet, ep-zo – epidote-zoisite, amp – amphibole, px – pyroxene and ky – kyanite. it is calculated on the basis of the four decimal places of the percentage contents of the analyzed minerals. a higher w.i. of a horizon indicates significant or repeated weathering of the analyzed grains due to prolonged exposure to a warm and humid geochemical environment (pedogenesis) and/or resedimentation. 2.2.5. petrographic analyses determining the composition of gravels and coarser sands provides information about the mineral composition and the origin of the source material. in order to determine the age of carbonate grains, micropalaeontological analyses were carried out. petrographic analyses were carried out at the geological institute of serbia. thin-sections of sand grains were prepared and examined under the carl zeiss polarizing microscope, and petrographic and micropalaeontological analyses were carried out. in addition, 15 pebbles were macroscopically examined, which were embedded as an interlayer in the palaeosol horizon 3. the interlayer is 3 – 7 cm thick and extends over approx. 0.8 m.a.s.l. it is subhorizontal, slightly inclined towards the sea (approx. 12°) and slightly undulating. pebbles with a 1 – 3 cm diameter were sampled along palaeosol horizon 3. most of the pebbles were too small to make thin-sections, so they were analyzed using lenses and acids (standard methods of macroscopic petrography). 2.2.6. osl dating the samples for the determination of the equivalent dose (de) were taken by hammering light­tight cylinders into the profile. the samples were prepared according to the procedures described in beerten et al. (2020, 2025). the quartz fraction between 90 – 250 µm was used for dating. osl measurements were performed with the riso osl/ tl-da-20 reader using blue led stimulation and a hoya u­340 uv filter to prevent stimulation light from reaching the pho tomultiplier tube. the measurements were done in the luminescence facility of the belgian nuclear research centre sck cen. several aliquots (24) were prepared for each sample, using a 2 mm thick mask and silicone oil spray to attach the grains to stainless steel disks. artificial doses were delivered using the built-in sr-90 beta source operating at a dose rate of 111 mgy/s. routine osl measurements were performed by stimulating the sample for 40 s at 125 °c. osl intensities were determined using the first 0.48 s of the signal and an early background subtraction (0.8 – 1.6 s). three dose points were used for de-determination, with one recycling and one zero dose point. g eologia c roatica 225ružičić et al.: deciphering the pedo-sedimentary complex of the eastern adriatic coast: a case study from privlaka, croatia dose recovery and preheating plateau tests were performed to verify the performance of the applied single aliquot regeneration (sar) protocol according to the recommendations of murray & wintle (2003). in the dose recovery test, natu ral aliquots were bleached, and a known dose was given close to the expected dose measured by the sar protocol. four aliquots were used for each preheating temperature (10 s) in the range of 180 – 260 °c. these tests allowed us to select an appropriate preheat temperature of 240 °c (10 s) and a cut heat temperature of 200 °c. the subsequent dose recovery test resulted in a recovery rate of 0.98 ± 0.02. the relative standard deviation in the dose recovery test was 4.9%. for the de­ cal­ culation, aliquots were accepted if the values for recovery and recycling were <10 %. samples for the determination of dose rate (d) were taken after removing the osl sampling cylinders from the profile by collecting sufficient sediment from the surrounding matrix (20 – 30 cm diameter from the sampling point). the dried sedi­ ment mass (105 °c) was then placed in tightly sealed plastic bottles (200 ml) and stored for three weeks. the samples were then measured using high-resolution gamma spectrometry. the activity concentrations were converted to radionuclide concentrations of the respective parent isotope (238u, 235u, 232th and 40k), from which the dose rates were calculated using the conversion factors of adamiec & aitken (1998). the dose rates were corrected for water content and beta dose attenuation (correction factor 0.9). based on a qualitative assess ment of the site history, the time-averaged water content was set to 10%, with a relative uncertainty of 0.5 times this value. the cosmic dose rates were calculated according to prescott & hutton (1994), and the internal alpha­radio­ activity was considered (vandenberghe et al., 2008). 3. results 3.1. field description of pedo-sedimentary complex the privlaka pedo-sedimentary complex is located about one kilometre northwest of the center of the privlaka settlement. as shown in figure 2a, the 8 m thick succession is divided into five units. nineteen horizons/layers were identified during the field investigations (table 1). the first unit (i) is divided into 8 horizons, the second (ii) into 5 layers, each with two subtable 1. summary of the field description of the studied pedo-sedimentary succession. unites / thickness (cm) layer / horizon sub-layers depths (cm a.s.l.) thickness (cm) color reaction with hcl reaction with h2o2 rec / ~ 40 not sampled. iv / ~ 150 not sampled. iii / ~ 230 19 568-600 n.a. 2 n.a. 18 18-3 528-568 40 10yr 4/6 2 0.5 18-2 518-528 10 10yr 5/6 2 n.a. 18-1 503-518 15 10yr 5/6 2 0.5 17 470-503 33 10 yr 5/8 2 0.5 16 446-470 24 10 yr 5/6 2 0.5 15 15b 420-446 26 10 yr 5/8 2 0.5 15a 407-420 13 10 yr 5/8 2 n.a. 14 14b 385-407 22 10 yr 5/8 2 0.5 14a 370-385 15 10 yr 6/6 2 0.5 ii / ~ 120 13 13b 361-370 9 10 yr 6/6 2 0.5 13a 354-361 7 10 yr 6/6 2 n.a. 12 12b 350-354 4 10 yr 5/8 2 0.5 12a 336-350 14 10 yr 6/6 2 n.a. 11 11b 315-336 21 10 yr 5/6 2 0.5 11a 304-315 11 10 yr 5/8 2 n.a. 10 10b 295-304 9 10 yr 4/6 2 0.5 10a 284-295 11 10 yr 5/6 2 n.a. 9 9b 279-284 5 10 yr 6/6 2 0.5 9a 269-279 10 10 yr 5/6 2 0.5 i / ~ 250 8 230-263 33 5yr 4/6 2 2 7 208-230 22 5yr 5/6 2 2 6 148-208 60 5yr 4/6 2 2 5 138-148 10 7.5yr 5/6 2 2 4 95-138 43 7.5yr 5/6 2 1 3 72-95 23 7.5yr 5/6 2 1 2 44-72 28 5yr 4/6 2 2 1 0-44 44 5yr 5/6 2 2 legend: 2 – bursting bubbles (evident dissolution); 1.5 – big bubbles; 1 – hearing, small bubbles; 0.5 – only hearing; n.a.– not analyzed g eo lo gi a c ro at ic a 226 geologia croatica 78/3 layers, and the third unit (iii) into 6 layers. the two lower layers of unit iii are divided into two sub-layers, and the upper layer consists of three sub-layers. the two upper units, four (iv) and recent soil (rec), were not accessible. a total of 21 samples were collected. secondary carbonates, such as rhizoconcretions, pseudomycelium, carbonate nodules, carbonate concretions and scattered carbonate, were identified and clas­ si fied following retallack (2019) and poch et al. (2024) and references within. unit i – palaeosol the lowest package (unit i, with a thickness of more than 250 cm) indicates the reddish palaeosol (fig. 2a, b). at the bottom of unit i is a sandy, loamy, slightly yellowish red (5yr 5/6) palaeosol soil horizon 1 with a thickness of about 44 cm (fig. 2c; table 1; munsell soil colour charts, 2013). vertically oriented carbonate concretions (rhizoconcretions) with a diameter of 8 – 12 cm are precipitated at a depth below 35 cm of horizon 1 (fig. 2c). in addition to the concretions, an accumulation of carbonate nodules (gravel-sized) can be observed in the upper part of horizon 1. the second palaeosol horizon 2 of the investigated profile pn1­5 lies between 44 and 72 cm (fig. 2c). it is a coarse­grained, sandy clay that is darker yellowish red (5yr 4/6) and has a thickness of 28 cm. ver­ tically oriented carbonate concretions 5 – 10 cm in diameter with rounded carbonate nodules are developed. in addition, this horizon shows a lot of carbonate coatings and scattered carbonate in the matrix of this horizon. the boundary with the lower horizon 1 is clear and undulating. the next horizon 3 of the palaeosol part of the profile con­ sists of 23 cm thick, strongly brown (7.5yr 5/6) loamy sand (fig. 2c; table 1). it consists of several thin gravel layers composed of igneous rock pebbles that are moderately and discontinuously cemented by carbonate minerals. the boundary with lower horizon 2 is gradual and undulating. horizon 4 of the palaeosol unit is between 95 and 138 cm (fig. 2c; table 1). it is a strong brown (7.5yr 5/6) clay loam with a thickness of 43 cm. there are accumulations of car bo­ nate nodules, which are harder in the lower part (lower 10 cm) of the horizon. the carbonate nodules are sporadically rounded (up to 2 cm) or vertically oriented (fig. 2c). the boundary to the lower horizon is distinct and undulating. horizon 5 of the palaeosol consists of a 10 cm thick, strongly brown (7.5yr 5/6) clay loam. this horizon is dominated by gravel clasts (<6 mm) consisting of quartz and calcite. these rock fragments are covered with layers of clay, which can also be found on the walls of the root channels. the boundary to horizon 4 is undu­ lating and sharply defined. horizon 6 of the palaeosol lies between 148 and 208 cm (fig. 2c; table 1). the soil texture of this horizon is sandy loam with a yellowish red colour (5yr 4/6). this horizon shows an accumulation of vertical carbonate nodules or rhizoconcretions. the boundary with the underlying horizon 5 is undulating and gradual. palaeosol horizon 7 consists of a 22 cm thick yellowish red (5yr 5/6) sandy loam with angular or subangular gravels (<6 mm). this horizon is characterized by carbonate coatings. the boundary to horizon 6 is undulating and clear. the uppermost palaeosol horizon 8 lies between 230 and 263 cm (fig. 2c; table 1). the soil texture of this horizon is clayey loam with a yellowish red colour (5yr 4/6). this horizon contains spherical, partially dissolved carbonate concretions and indeter minate infillings of the channels, such as wedges. the boun­ dary with horizon 7 is undulating and sharp. unit ii – glacio-fluvial material unit i is followed by the glacio­fluvial material of unit ii (fig. 2a, b, c; table 1), which consists of ca. 10 cm thick cyclic events (total thickness 120 cm), with grain size fining upward. the lower parts of the layers of unit ii consist of coarsergrained particles and carbonate nodules, partly cemented by calcium carbonate. in addition, several gravelly channel infil­ lings and intercalations have been observed, along with imbrication of clasts were observed. the boundary between the palaeosol and the overlying sediment is abrupt, indicating erosion of the underlying sediment or palaeosol. the lowest layer 9 of unit ii (269 – 284 cm), which is divided into sub­ layers 9a and 9b, has a yellowish brown (10yr 5/6) to brownish yellow (10yr 6/6) colour (fig. 2a, b, c; table 1). this layer is silty to gravelly sand with carbonate and silicate components. this layer contains subangular carbonate pebbles with a maximum size of 6 cm. the next layer above 10 (284 – 304 cm) with the sub­layers 10a and 10b consists of loamy to silty sand with sporadic clasts of partially cemented pebbles (approx. 1.5 cm). this layer has a yellowish brown (10yr 5/6) to dark yellowishbrown colour (10yr 4/6). layer 11 (sublayers 11a and 11b) consists of an 11 cm thick yellowish brown (10yr 5/8) loamy or silty sand with poorly sorted and partially cemented grains (fig. 2b, c; table 1). spherical carbonate concretions with a diameter of 1 – 5 cm form up to 70% of this layer. lens­like structures (30 cm wide and 3 cm deep) filled with gravel have developed in this layer. layer 12 (336 – 354 cm) is divided into sublayers 12a and 12b and has a brownish-yellow (10yr 6/6) to yellowishbrown (10yr 5/8) colour (fig. 2c; table 1). this layer is a wellsorted silty to gravelly, partially cemented sand. the upper part of this layer contains spherical concretions (15 cm) occurring in smaller lenses. there are also spherical carbonate concretions with a diameter of approx. 4 cm. layer 13 (depth 354 – 370 cm, sub­layers 13a and 13b) has a brownish yellow colour (10yr 6/6). this layer is silty sand with gravel (the grain size fines upward from gravel to silty sand). predominantly spherical carbonate concretions 7 cm in diameter are partially cemented and associated with fine­grained material. the coating of clasts was observed in these materials. the boundaries between sub­layers 13a and 13b are distinct and undulating. unit iii – glacio-fluvial material unit ii is continuously followed by unit iii with a thickness of about 230 cm. it appears that the material of unit iii is consistent with the material of unit ii, but shows differences in the duration of the cyclic events (the layers described are thicker in unit iii), but still shows a relative trend of fining upward, with obvious gravel intercalations (fig. 2a, b, c; table 1). g eologia c roatica 227ružičić et al.: deciphering the pedo-sedimentary complex of the eastern adriatic coast: a case study from privlaka, croatia layer 14 is divided into sub­layers 14a and 14b (370 – 407 cm) and consists of brownish­yellow (10yr 6/6), partially cemented, silty-gravelly sand. predominantly hemispherical carbonate concretions with a diameter of 1.5 – 3 cm are observed. this layer shows an increasing refinement of the grain size upward. layer 15 (depth 407 – 446 cm, with sub­layers 15a and 15b) consists of yellowish-brown (10yr 5/8) well-sorted gravelly sand with silt. spherical carbonate concretions 2.5 cm in diameter are observed. pebbles fill subvertical cracks developed from roots. the boundary with the lower layer is diffuse and irregular. layer 16 consists of 24 cm thick yellowish­brown (10yr 5/6) silty sand with rare subrounded gravel clasts (fig. 2c; table 1). there are fining material upward cycles (from 12% gravel in the lower to 5% in the upper part of the horizon). subvertical root channels with carbonate coatings appeared in this layer. these holes are the boundary to the lower layer which is diffuse and irregular. the next layer 17 consists of silty sand with rare pebbles (up to 4 mm) and has a yellowish­ brown colour (10yr 5/8). root holes with sporadically infilled fine­grained material are observed. the boundary with the lower layer is diffuse and irregular. layer 18 is developed between 503 and 568 cm and was divided into three sublayers 18­1, 18­2 and 18­3 based on the alteration of three sets of coarse-grained material with concretions (partial cemented) and fine­grained material (fig. 2c; table 1). the coarse-grained material is 8 cm thick and consists of gravelly silty sand. the fine­grained material has a thickness of 1.5 cm and consists of silty sand. the sub-layer 18-1 consists of 15 cm thick gravelly sand with clasts up to 5 mm. this sub-layer is partially cemented with silt. the mostly spherical carbonate concretions with a diameter of 1.5 – 2 cm are post-sedimentary connected with the silt. traces of recent animal burrows were found in sub-layer 18-2. the gravelly to silty sand is incompletely cemented. sub­layer 18­3 consists of 40 cm thick, silty sand. it is weakly lithified and cemented with silt. in some places, fine material is observed towards the top. the boundary with the upper layer 19 is diffuse and undulating and is defined by a difference in texture and orientation of the accumulated secondary carbonates. layer 19 (568 – 600 cm) is a very compact silty sand with gravel. subvertically oriented concretions (rhizoconcretions) were observed. unit iv – glacio-fluvial material and unit rec – recent soil unit iv was formed from glacio­fluvial material with a total thickness of ca. 150 cm (fig. 2a; table 1). there are cyclic events in which the grain size becomes finer towards the top. at the top of the pedo-sedimentary complex is the rec unit. it consists of about 40 cm of recent, intensively rooted, weak soil. due to the very inaccessible, collapse-prone material, the two uppermost units of the pedo-sedimentary complex were not sampled. 3.2. grain-size distribution according to the grain size analysis, the sand fraction predominates in the upper part (gf), while silt predominates in the lower part (ps) of the profile (fig. 3). medium and fine sand grains seem to equally represent the sand fraction in the gf material. therefore, most samples are classified as fine sand or, more rarely, medium sand (wentworth, 1922). in the lower part of the profile (ps), the silt component predominates, although there are some parts with more than 20% sand content and less than 40% silt (fig. 3). most of the samples are medium to coarse silt (wentworth, 1922). the clay configure 3. grain size of the profile pn1-5. the red dashed subhorizontal line represents the border between unit i – palaeosol(s) (ps) and unit ii – glaciofluvial material (gf). g eo lo gi a c ro at ic a 228 geologia croatica 78/3 tent is higher in the palaeosol, where the pedogenetic processes were most intense. there is no significant difference in the shape of the grains between the samples examined (table 2). both roundness (rang ing between 0.14 and 0.62) and sphericity (ranging between 0.14 and 0.68) show a decreasing tendency with smaller grain sizes in most of the individual samples. only two samples consist of subangular grains. one from palaeosol and the other from (glacio­) fluvial material. almost all samples show a medium sphericity. two samples (3 and 18­3) have low sphericity. 3.3. physico-chemical properties the results of the physico-chemical properties within the pn1­5 profile are shown in figure 4. all analysed samples have an alkaline phh2o (>7.5). the percentage of organic matter (om) is higher in the palaeosol part of the profile than in the glacio­fluvial part, which is due to pedogenetic development. the caco3 content generally decreases with depth. in the upper part of the profile (glacio­fluvial sediments), this content varies between 60.8% and 86.7%, while in the lower part it is between 16.8% and 29.7%. 3.4. mineralogical properties the mineralogical composition (of the <2 mm fraction), indicates the predominant mineral phases identified by x-ray powder diffraction in the bulk sample, and is shown in table 3. the predominant minerals in the palaeosol horizons in the lower part of profile pn1­5 are calcite and quartz. the samples also contain feldspars, goethite, phyllosilicates and sporadically titanium oxides (table 3). two types of calcites are dis tinguish ed in the palaeosol and glacio­fluvial sediments: primary calcite, which was formed by the process of physical weathering of carbonate rocks from the hinterland, and secondary, i.e., authigenic calcite, which was precipitated as cement in carbonate concretions and rhizoconcretions during pedogenesis. table 2. results of the morphologic analysis of the grains (krumbein & sloss, 1963). sample roundness description sphericity description fraction (mm) fraction (mm) 1-0.5 0.5-0.25 0.25-0.125 0.125-0.09 0.09-0.045 1-0.5 0.5-0.25 0.25-0.125 0.125-0.09 0.09-0.045 18-3 0.158 0.149 0.146 0.143 0.618 subangular 0.675 0.651 0.638 0.63 0.142 low sphericity 17 0.181 0.156 0.147 0.143 angular 0.678 0.648 0.626 0.611 moderate sphericity 13b 0.183 0.167 0.147 0.142 angular 0.678 0.655 0.635 0.626 moderate sphericity 9b 0.158 0.148 0.144 0.141 angular 0.66 0.645 0.631 0.618 moderate sphericity 9a 0.186 0.171 0.153 0.147 angular 0.655 0.633 0.615 0.596 moderate sphericity 8 0.172 0.156 0.147 0.143 angular 0.675 0.651 0.636 0.618 moderate sphericity 7 0.188 0.164 0.148 0.145 angular 0.685 0.655 0.64 0.626 moderate sphericity 6 0.17 0.157 0.148 0.145 angular 0.683 0.668 0.656 0.643 moderate sphericity 5 0.166 0.157 0.147 0.149 angular 0.686 0.663 0.645 0.631 moderate sphericity 4 0.168 0.157 0.149 0.145 angular 0.673 0.66 0.638 0.625 moderate sphericity 3 0.21 0.181 0.163 0.149 angular 0.581 0.58 0.568 0.56 low sphericity 2 0.189 0.172 0.162 0.153 angular 0.648 0.631 0.608 0.601 moderate sphericity 1 0.241 0.221 0.196 0.172 subangular 0.638 0.635 0.626 0.618 moderate sphericity table 3. semi-quantitative determination of mineral composition in paleosol and (glacio-)fluvial samples on the fraction <2 mm. sample mineral composition of fraction <2 mm qtz cal k-fs pl gt tiox phy 18-2 **** *** * * * 17 ** **** * * * 13b ** **** * ~ * * 9b ** **** * 9a ** **** * * 8 *** *** * * * ~ ** 7 ** **** * * * * 6 *** ** * * * ** 5 *** **** * * * 4 ** *** * * * ~ ** 3 ** *** * * * ** 2 *** *** * * * ** 1 **** ** * * * ** legend: qtz – quartz, cal – calcite, phy – phyllosilicates, k-fs – potassium feldspar, pl – plagioclase, gt – goethite, tiox – titanium oxides (rutil and anatas) **** – predominant (> 50 w%), *** – dominant (35 – 50 w%), ** – abundant (15 – 35 w%), * – subordinate (1 – 15 w%), ~ in traces (< 1 w%). g eologia c roatica 229ružičić et al.: deciphering the pedo-sedimentary complex of the eastern adriatic coast: a case study from privlaka, croatia after carbonate dissolution (table 4) the visibility of titanium oxides increased. they are identified in nearly all in­ soluble residue samples, typically as subordinate compo nents, and as traces in some samples. these results indi cate that titanium oxides are a consistent but minor component of the mineral assemblage, the detectability of which increases after carbonate dissolution. in some horizons there is sporadic evidence of chromium hydroxides, manganese hydroxides and magnetite. however, this cannot be confirmed with certainty as the diffraction reflections of these minerals overlap with the diffraction reflections of some other mineral types. quartz is the dominant mineral in the insoluble residue of glacio­fluvial sediments. other minerals identified in the insoluble residue are feldspars and goethite. unlike goethite, the content of which is unchanged in both parts of the profile, the content of feldspar is somewhat more variable. very broad and less intense diffraction reflections of 10 å and 14 å from clay minerals indicate their presence in the very small size fraction. they are more abundant in the palaeosol than in the gf sediments of the upper part of the profile. their abundance also changes over the profile, which could be related to illu­ viation processes. 3.5. modal analysis the lmf is about 98% in almost all samples (fig. 5; table 5), with quartz being the dominant component (79 – 92%) (table 6), followed by lithic particles (5 – 15%) and feldspars (3 – 7%). volcanic glass is an accessory (<3 %). fresh quartz figure 4. distribution of the caco3 (%), ph, and om (%) along the pn1-5 profile. table 4. semi-quantitative determination of the mineral composition of insoluble residue. sample mineral composition of insoluble residue qtz k-fs pl gt tiox crhox phy mg 18-2 **** * * ** 17 **** * * * ** 13b **** ** * * ** 9b **** * * * * * 9a **** * ** * * * 8 *** ** * * ? *** 7 ** * * * *** ? 6 ** * ** * ~ **** ? 5 ** ** ~ ? **** ? 4 *** * * * ~ *** 3 *** ** * * *** 2 ** ** * * * **** 1 ** * * * **** legend: qtz – quartz, k-fs – potassium feldspar, pl – plagioclase, gt – goethite, tiox – titanium oxides (rutil and anatase), crhox – chromium hydroxides, phy – phyllosilicates, mg – magnetite, ? – indication for the presence, ~ in traces (< 1 w%) g eo lo gi a c ro at ic a 230 geologia croatica 78/3 grains are often idiomorphic (fig. 6a) with (zircon) inclusions. there is a general trend towards an increase in the proportion of weathered quartz grains compared to fresh ones (fig. 6b), which increases with the age of the samples (fig. 2). the ratio ranges from almost 3 in the oldest palaeosol to 1.5 and 2.5 in the overlying palaeosol horizons and the older glacio­fluvial sediments to about 1 (equal distribution of weathered and fresh grains) in the uppermost 2.5 m of the studied part of a profile pn1­5 (fig. 2). this ratio is not reliable when applied to feld spars, as these are only minor contributors to the mineral assem blage (tables 5 and 6). plagioclase is rare; weathered k-feldspars are mostly represented by orthoclase, rarely by micro cline. weathered feldspars are kaolinized and sometimes even sericitized and contain no inclusions, while fresh feldspars are sanidine or adular. in rare cases, they contain inclusions that have been determined as idiomorphic zircon inclusions. some fresh feldspar grains consist of hypidio morphic sanidine (fig. 6c). lithic particles are represented by quartzite (2 – 10%), chert (3 – 11%) and rarely by volcanic glass (up to 1(3) %). horizons 16 – 18­1 are enriched with quartzite, and horizon 14b with chert (table 5). some chert particles are siliceous spicules of fossil sponges exposing the internal axial channel (fig. 6d) and the fossil zonal chert ball (fig. 6e). some cases may represent myrmekite intergrowths. the quartzite crystals are characterised by undulous extinction. volcanic glass is sometimes clear with weak negative relief but usually devitrified and represented by spherulites of radial quartz fibres with extinction cross (n+). it may be a chalcedony with a “maltese cross” (fig. 6f). volcanic glass with inclusions and devitrified volcanic glass is enriched in the 15b horizon. in addition to the reported lithic particles, serpentinite particles (specific density 2.6 g cm-1) plastered with quartz grains are found in the oldest 18-1 horizons (fig. 6g). figure 5. modal composition of the lmf (values in %). g eologia c roatica 231ružičić et al.: deciphering the pedo-sedimentary complex of the eastern adriatic coast: a case study from privlaka, croatia table 5. modal composition of light mineral fraction (values in %) and weathering index (legend in table 6). sample depth from the surface (cm) quartz feldspar lithic particles 2w.i. k-feldspar plagioclase fresh weathered fresh weathered fresh weathered quartzite chert 1v.g. 18-3 528–568 35 44 3 3 0 + 8 6 1 35 18-1 503–518 36 47 1 3 0 0 10 3 0 36 17 470–503 45 35 4 3 0 0 10 3 + 45 16 446–470 34 46 2 2 0 0 10 5 1 34 15 b 420–446 44 40 3 3 + + 5 3 3 44 14 b 385–407 37 46 1 2 0 0 3 11 + 37 14 a 370–385 38 47 2 4 + 0 2 6 0 38 13 b 361–370 40 45 2 2 0 0 4 7 0 40 12 b 350–354 41 43 3 1 0 0 6 6 + 41 11 b 315–336 33 52 1 5 0 0 6 4 1 33 10 b 295–304 28 58 2 2 0 0 6 3 + 28 9 b 279–284 38 50 2 3 0 + 4 3 1 38 9a 269–279 29 60 2 1 0 0 5 3 + 29 8 230–263 37 47 2 4 + 0 8 3 0 37 7 208–230 34 53 1 2 0 0 6 4 + 34 6 148–208 30 57 2 2 0 + 3 5 1 30 5 138–148 29 59 2 2 0 + 3 5 0 29 4 95–138 24 61 2 3 0 + 4 4 1 24 3 72–95 29 53 2 3 0 1 7 5 1 29 2 44–72 27 62 2 1 0 0 4 4 1 27 1 0–44 24 68 3 0 0 0 2 3 0 24 1v.g. – volcanic glass; 2w.i. – weathering index; + – minerals with occurrence <0.5 % table 6. modal composition of heavy and light mineral association. sample composition of lmf 100% hmf % composition of hmf 100% transparent heavy minerals 100% qz fsp l v.g. op gth chl bt thm ep-zo amp px grt ky st tur zrn rt ttn chr 18-3 79 6 14 1 1.87 54 18 + 0 27 5 2 5 43 0 1 5 13 14 1 10 18-1 83 4 13 0 2.33 57 13 1 0 30 7 1 8 46 2 2 9 14 6 1 5 17 80 7 13 + 2.51 30 30 + + 40 6 2 6 37 0 1 6 20 12 4 6 16 80 4 15 1 2.31 36 22 0 0 42 7 1 4 46 0 1 4 18 13 1 5 15 b 84 6 8 3 2.16 36 21 0 0 44 7 2 9 29 1 1 3 18 17 5 8 14 b 83 3 15 + 1.82 38 26 0 0 37 8 2 10 27 3 4 7 15 19 1 3 14 a 86 7 8 0 1.68 44 18 0 0 38 3 1 9 40 0 2 13 14 14 3 1 13 b 85 4 11 0 1.94 36 17 + 0 46 7 0 5 51 1 2 5 12 13 0 5 12 b 83 4 12 + 1.31 31 26 0 + 43 4 2 7 28 1 4 4 20 21 4 5 11 b 85 6 9 1 1.76 36 33 1 + 31 5 4 5 39 0 4 9 11 15 3 6 10 b 87 4 9 + 1.24 36 29 0 1 34 9 4 13 31 0 3 11 14 9 2 5 9 b 87 5 7 1 1.88 47 24 0 0 29 5 6 8 34 2 4 13 8 11 4 4 9a 90 3 7 + 2.34 35 23 0 + 42 5 5 11 25 1 3 4 24 17 2 4 8 84 6 10 0 1.76 31 32 1 0 36 6 3 7 39 1 1 11 9 15 5 3 7 87 3 10 + 1.78 35 28 0 0 37 9 0 5 37 2 2 4 10 21 2 9 6 87 5 8 1 2.14 32 31 0 0 37 2 2 6 35 0 1 8 10 21 6 10 5 88 4 8 0 1.08 36 28 0 1 36 6 3 12 33 0 3 7 15 8 8 8 4 85 5 9 1 1.16 48 16 0 + 35 6 1 8 35 1 4 10 11 15 6 2 3 82 6 12 1 1.26 45 23 0 0 32 9 5 8 32 0 2 15 12 15 0 3 2 89 3 8 1 1.24 42 24 0 + 34 7 2 7 33 0 2 9 17 18 1 3 1 92 3 5 0 2.05 52 12 + 0 35 6 5 4 39 0 1 4 15 10 0 18 legend: lmf – light mineral fraction, hmf – heavy mineral fraction, thm – transparent heavy minerals, qz – quartz, fsp – feldspar, l – transparent lithic particles, op – opâque minerals, gth – goethite, chl – chlorite, bt – biotite, ms – muscovite, ep-zo – epidote-zoisite, amp – amphibole, px – pyroxene, grt – garnet, ky – kyanite, st – staurolite, tur – tourmaline, zrn – zircon, rt – rutile, ttn – titanite, chr – chromite, ap – apatite, v.g. – volcanic glass, + – minerals with occurrence <0.5 % (symbology according to warr 2021). g eo lo gi a c ro at ic a 232 geologia croatica 78/3 the distribution of the hmf is mostly uniform across the pn1­5 profile and lies between 1.08% and 2.51% (fig. 7; table 5). opaque grains predominate among the hmf. in addition to indeterminate opaque grains (30 – 57% of the sample), there are also goethite grains (12 – 33%). when viewed under higher illumination, goethite microcrystals appear reddish in crossed nicols, whereas in parallel nicols they appear opaque due to their red microcrystals. they are alteration products of mafic minerals and often coat grains. the goethite grains are also roundish and have a high sphericity. due to their uniqueness, figure 6. photo-micrographs of minerals from the lmf and hmf of samples of the investigated pn 1-5 profile in parallel (n-) or crossed (n+) nicols: a quartz fresh idiomorphic with inclusions (1), weathered (2) and with regeneration edge (3), n+, 7; b weathered and fresh quartz, n-, 2; c fresh hypidiomorphic sanidine with inclusions, n-, 3; d siliceous spicule of fossil sponge with the internal axial channel, n+, 6; e fossil zonal chert ball, n-, 10b; f spherulites of radial fibres of quartz with extinction cross, n+, 3; g serpentinite, nand n+, 1; h rounded, allotriomorphic and weathered garnet and tourmaline, n-, 1; i fresh idiomorphic zonal garnet, n-, 9b; j rounded zircon, n+, 1; k idiomorphic zircon, n-, 9a; l fresh zoisite with anomalous blue interference colour, n-, 11b; m chromite, n-, 1; n yellowish cr-rich spinel (picotite?), n-, 1; o fresh hornblende, n-, 12b; p glaucophane, n-, 14b. g eologia c roatica 233ružičić et al.: deciphering the pedo-sedimentary complex of the eastern adriatic coast: a case study from privlaka, croatia they are separated from the opaque grains, although they are part of them. the flaky minerals chlorite and biotite are rare (<1%), and muscovite is not present (except for some sericite grains). the proportion of transparent heavy minerals (thm) is 27 – 46% and shows no specific distribution trend (fig. 8; table 6). the most common transparent heavy minerals are resistant grains such as garnet (27 – 51%), followed by zircon (9 – 24%) and rutile (6 – 21%). garnet grains can be brownish, pinkish or yellowish (fig. 6h), but are usually colourless and rarely idiomorphic (fig. 6i). zircon crystals are usually (sometimes completely) rounded (fig. 6j), but idiomorphic crystals are not uncommon (fig. 6k). smaller amounts of tourmaline (3 – 15%), pyroxenes (4 – 13%) and chromite (1 – 18%) are present. tourmaline crystals are often roundish, allotriomorphic and weathered (fig. 6h), rarely idiomorphic and hypidiomorphic crystals. the pleochroic colours are olive green, black and colourless to yellowish. it is partially enriched in the palaeosol. in horizon 11b, all tourmaline crystals are regularly allo triomorphic. the pyroxenes are mostly orthopyroxene, which is rarely fresh and is clearly enriched in the oldest horizon 6. the epidote-zoisite group (2 – 9%), titanite (<8 %), amphibole (<6 %), staurolite (1 – 4%) and kyanite (<2 %) only occur spo­ ra dically. the epidote-zoisite group is predominantly represented by zoisite, which has an anomalous blue interference colour. fresh grains are more common in samples 10b and 11b (fig. 6l). in addition to chromite as cr-rich reddish spinel (fig. 6m), this category also includes spinels of other colours, such as yellowish-brown cr-rich spinel (picotite?), which is cha racteristic of basic and ultrabasic rocks and is associated with volcanic rocks, peridotites and serpentinites (fig. 6n). amphifigure 7. modal composition of the hmf (values in %) (legend in table 5). g eo lo gi a c ro at ic a 234 geologia croatica 78/3 boles are represented by hornblende, and the pleochroic colours are dark green and olive green. it may be entirely fresh (fig. 6o) or chloritized with black inclusions (probably magnetite) as an alteration product. glaucophane is detected in the 14b horizon (fig. 6p). 3.6. petrographic analysis horizon 3 consists of angular to rounded carbonates (2/3 of the grains) and rounded dark chert pebbles (1/3 of the grains). only one sample was determined as serpentinized olivine basalt (fig. 9). the carbonates are of polygenetic origin, and they are formed in equal parts by strongly spherical, sub rounded to rounded rudist limestones from the upper cretaceous and nummulitic limestones from the eocene, as well as by lowspherical, angular to subangular carbonate concretions. based on the analysis of the rock fragments (table 7), their composition, degree of roundness, and sorting, it can be concluded that the material has passed through several sedimentation cycles. the fragments are rounded to a considerable extent, the material was derived mainly from carbonate areas formed in different sedimentary environments, predominantly in shallow water areas, but also with some fragments from deep water areas of the basin represented. the well-rounded and sorted grains of the rock fragments sampled in sublayer 9a are documented in figure 10 as a) biconcava bentori hamaoui and saint-marc, b) nezzazatidae, c) cuneolina sp., d) rotalia sp., e) nezzazatidae, f) a – lituolidae, b – pseudonummoloculina, g) heterohelix globulosa ehrenberg, h) c – calcisphaerulidae, h – heterohelix, i) miliolidae, j) valvulinidae, k) rotalia sp. and l) rotalia sp. the determined fossils indicate an upper cretaceous age. the dark pebble grains contain a selection of calcareous spherules (calcisphaerulidae and heterohelix globulosa ehren berg), which represent a deep-sea micro-association characteristic of the pelagic environment. they most probably have a turonian – senonian age. in the limestone grains, a shallow-water association consists mainly of benthic foraminifera (miliolidae, textulariidae, valvulinidae, biconcava ben tori figure 8. modal composition of the tmf (values in %) (legend in table 5). g eologia c roatica 235ružičić et al.: deciphering the pedo-sedimentary complex of the eastern adriatic coast: a case study from privlaka, croatia hamaoui and saint-marc, cuneolina sp., lituolidae, milio lidae, nezzazatidae, pseudonummoloculina, quinqueloculina sp.) and bryozoans. the age of these grains is probably also in the upper cretaceous (representing the cenomanian to lower senonian, based on particular microfossils). 3.7. osl dating the results of the osl dating of the upper gf complex are shown in tables 8 and 9 as well as in figure 11. the dose rate values are rather low, which can be explained by the relatively high quartz content of the samples. the relative standard deviation (rsd) of the measured dose populations is relatively large compared to the rsd of the dose determining test result (i.e. 5%), ranging between 21 – 31%. since it is assumed that the site was saturated for a period and then very dry conditions prevailed in an indurated sediment mass, it can be assumed that bioturbation would have been a difficult process, causing mixing of the sediment and responsible for the observed overdispersion. however, given the glacio­fluvial nature of the sediment, insufficient bleaching of the quartz grains prior to deposition could be a problem. therefore, we examined the dose populations towards smaller doses and attempted to table 7. percentage of rock fragments in a certain fraction of paleosol horizon 3. type of rocks 2-1.25 mm 2-0.9 mm 20.5mm <1.25mm <0.9mm 0.5-0.06mm % micritic limestone 19.77 31.14 43.27 17.42 16.67 30.15 microsparitic limestone 63.95 56.28 40.71 71.61 68.23 19.14 sparitic limestone 8,14 5.39 6.41 3.87 9.38 9.55 siliciclastic rocks 5.81 7.19 8.33 5.16* 2.08* 39.31** bioclastic 2.33 1.28 2.08 1.12 rock fragments (fe rocks) 1.94 1.56 0.73 σ 100 100 100 100 100 100 legend: *chert; **chert, quarzite, quartz figure 9. photo-micrograph of serpentinized olivine basalt with crossed (n+) nicols. table 8. depth, water content (w.c.), activity concentrations (bq/kg) and dose rate (gy/ka) estimate. sample horizon depth (cm) w.c. (%) th-232 (bq/kg) u-238 (bq/kg) u-235 (bq/kg) k-40 (bq/kg) dose rate (gy/ka) pn5-7 18 464 10 ± 5 7.7 ± 0.4 15 ± 3 0.69 ± 0.12 51 ± 3 0.70 ± 0.04 pn5-6 17 513 10 ± 5 13.7 ± 0.7 16 ± 4 0.74 ± 0.19 105 ± 6 0.96 ± 0.06 pn5-5 14b 604 10 ± 5 15.2 ± 0.7 13 ± 3 0.60 ± 0.14 80 ± 4 0.85 ± 0.05 pn5-4 13b 634 10 ± 5 18.9 ± 0.9 16 ± 4 0.74 ± 0.19 115 ± 6 1.05 ± 0.03 pn5-3 9b 718 10 ± 5 16.5 ± 1.0 13 ± 5 0.30 ± 0.15 85 ± 6 0.86 ± 0.06 g eo lo gi a c ro at ic a 236 geologia croatica 78/3 establish an apparent minimum age for the osl samples. the minimum age is calculated using the “bottom 5%” method (i.e., in this case, an age derived from the aliquots with the two lowest dose values) from olley et al. (1998) and is compared with the arithmetic mean. the latter is intended to be representative for the maximum age, given the fact that at least figure 10. photo-micrographs of course-sized sand grains from the 9a horizon: a biconcava bentori hamaoui and saint-marc; b nezzazatidae; c cuneolina sp.; d rotalia sp.; e nezzazatidae; f a – lituolidae; b – pseudonummoloculina; g heterohelix globulosa ehrenberg; h c – calcisphaerulidae; h – heterohelix; i miliolidae; j valvulinidae; k rotalia sp; l rotalia sp. g eologia c roatica 237ružičić et al.: deciphering the pedo-sedimentary complex of the eastern adriatic coast: a case study from privlaka, croatia some aliquots would contain a certain proportion of insuffi­ ciently bleached grains. of course, a significant proportion of the overdispersion is due to the heterogeneity in the beta dose rate. to summarize, the apparent osl ages of the gf sediment overlying the palaeosol range are between ca. 230 ka and 130 ka for the lowermost sample and ca. 190 ka and 105 ka for the uppermost sample. within the error limits, this means that the gf sediment in the minimum age scenario could have been deposited in the early weichselian ice sheet and the palaeosol would have a later eemian (mis 5e) or older age (cohen & gibbard, 2019). in the maximum age scenario, the glaciofluvial sediment could even have an age roughly corresponding to the second half of the saale ice age, which in turn means that the palaeosol could be as old as mis 7e or even older. 4. discussion the pedo-sedimentary succession of privlaka is located in the central area of the croatian part of the adriatic coast. the investigated section is represented by an almost 2.70 m thick palaeosol complex on which a more than 5 m thick package of glacio­fluvial sediments was deposited. the first ideas about palaeoglaciation of velebit mt., (the most extensive mountain range of the karst dinarides) in croatia, were developed at the beginning of the 20th century (žebre et al., 2021). the reconstructed ice cap area extended along the coastal mountains from risnjak mt. to south velebit mt. and across the range from lika polje to rab island (marjanac & marjanac, 2016). investigating the gla­ cial history of velebit mountain, marjanac & marjanac (2004) described glacio­fluvial late pleistocene sands and gra­ vels at an altitude of 900 m a.s.l., and glacio-lacustrine deposits (dominantly varved-like siltstones with dropstones) detected at sea level and below. they also detected those sediments on the opposite side of the velebit channel, at ražanac, as a pro­ bable time equivalent of those of the novigradsko more section. velić et al. (2011) describe glacio­fluvial sediments in detail. they are composed of material redeposited from the till. generally, glacio­fluvial deposits are composed of sub­ rounded clasts and pebbles, which are smaller and better sorted than those found in till. they were formed by erosion of glacial deposits, in which erosional channels can be found on both sides of the terminal moraine (velić et al., 2011). the pedo-sedimentary complex of privlaka is divided into five (5) units. the lowest unit i (thickness over 250 cm) shows the reddish palaeosol. this unit has vertically oriented carbonate concretions (rhizoconcretions) and carbonate nodules. the carbonate concretions in the base of the profile (fig. 2b) are most probably developed in situ through impregnation related to groundwater or sea level fluctuations, and the remaining carbonate accumulations in the profile originated from predominantly carbonate glacio­fluvial material and aeolian sediments (units ii, iii, iv and rec) (fig. 2). meteoric water enabled the dissolution, transport and precipitation of caco3 in different forms, as described by galović (2016). there are isolated magmatic pebbles associated with materials from the dinaric ophiolitic zone in the hinterland. the boundary to the upper unit ii is characterized by wedges, which can be interpreted as desiccation cracks or possibly even frost cracks. unit ii, the (glacio­) fluvial material, consists of approximately 10 cm thick cyclic units (total thickness 120 cm) with grain­size fining upward. this unit contains predominantly of spherical carbonate concretions and lenticular structures filled with gravel. subsequently, the material of unit iii shows a relative trend of fining upward, with clear gravel inter­ calations. as in unit ii, hemispherical to spherical carbonate concretions can be observed. in the upper part of this unit, subvertical root channels with carbonate coatings and subvertically oriented concretions (rhizoconcretions) occurred. unit iv consists of glacio­fluvial material with a total thickness of 150 cm. there are cyclic events in which the grain size fines upward. the long­distance transport of the glacio­fluvial material of units ii, iii and iv is confirmed by the presence of subrounded to rounded limestones. table 9. number of aliquots that passed the rejection criteria, the relative standard deviation (rsd, %) of that population, and equivalent doses (de; gy) and apparent ages (ka) based on the arithmetic mean and the lower 5% of the de population. sample no. aliq. rsd (%) arithmetic mean lower 5% de (gy) age (ka) de (gy) age (ka) pn5-7 24 31 135 ± 9 193 ± 17 74 ± 9 105 ± 15 pn5-6 23 24 180 ± 8 188 ± 15 101 ± 7 105 ± 10 pn5-5 24 28 185 ± 6 218 ± 15 76 ± 5 90 ± 8 pn5-4 24 22 196 ± 6 186 ± 13 122 ± 7 116 ± 10 pn5-3 22 21 198 ± 7 229 ± 18 110 ± 15 128 ± 20 figure 11. age-depth plot showing the lower 5% results as a minimum estimate, and the arithmetic mean as a maximum estimate, with indication of sampling position (horizon number). peak positions of significant interglacials (5e and 7e) and interstadials (5a, 5c, 7c and 7e) are indicated by vertical lines (cohen & gibbard, 2019). g eo lo gi a c ro at ic a 238 geologia croatica 78/3 in unit i, the increase in caco3 content can partly be attributed to secondary carbonates (also observed in the field) precipitated as cement in carbonate concretions and rhizo concre tions in the lower part of profile pn1­5. pfaffner et al. (2024) in their investigations of loess – palaeosol sequences found various forms and sizes of secondary carbonate accumula tion, i.e. pseudomycelia, hard nodules and soft carbonate concentrations. from the physico-chemical properties, it can be concluded that the higher caco3 content of unit ii (sub­layer 9a to 13b) is due to the increasing supply of the local lithogenic carbonate component (limestone fragments of sandy and silty grain size). according to the ph results, all the analysed samples are alkaline phh2o (>7.5). in horizons with higher ph values (fig. 4), carbonates can be found more frequently. durn et al. (2018a) determined similar ph values in red palaeosols formed on the northern adriatic island of susak. these soils were also enriched with carbonate concretions. the organic matter content is higher in the palaeosol part of the pedo-sedimentary complex, which can be attributed to the pedogenetic processes in the lower part of the studied profile. the grain-size analyses show that the sand fraction dominates in the glacio­fluvial (gf) sediments, while silt predo­ minates in the palaeosol (ps) (fig. 3). the upper part (gf) of the pn1­5 profile consists of fine or medium sands with several fining­upward sequences. the horizons of the palaeosol are classified as medium to coarse silts (wentworth, 1922). clay content is higher in the palaeosol, where pedogenetic processes were most intense. both roundness (ranging between 0.14 and 0.62) and sphericity (ranging between 0.14 and 0.68) show a decreasing trend with smaller grain sizes in most of the individual samples. banak et al. (2021) found similar roundness characteristics for quartz grains in their investigations on the adriatic coast. the authors concluded that the sand-gravel body is the result of sediment transport and deposition as part of a fluvial mechanism. the modal composition of the analyzed samples, as well as the freshness and morphology of the individual mineral grains, indicate the different origins of the grains. the analyzed total fraction of the 0.09 – 0.125 mm quartz grains in the lmf accounts for about 85% of the non-carbonate minerals (tables 5 and 6). comparing this with the proportion of quartz grains in the loess of continental croatia (galović, 2016; galović & peh, 2016), where quartz is also dominant but represented by only 50 – 75% of the lmf, it can be assumed that these sediments have undergone more redeposition than the grains of a typical continental loess. a similar proportion of quartz in the lmf is also present in the loess of the northern adriatic island of susak (50 – 60%) (mikulčić pavlaković et al., 2011). therefore, when faivre et al. (2019) examined flu­ vial sediments on the coast of the island of vis (central adriatic), they found that in most samples around 60% of the quartz grains were weathered. these samples contained more feldspars than in the present study, so they were also able to determine the proportions of fresh and weathered feldspars. weathered feldspar grains dominated 1.5 to 6.5 times. in privlaka, there is a general trend of an increase in the proportion of weathered quartz grains with depth (fig. 12). the ratio is about 1:1 in the upper part of pn1­5 profile (layer 12 and above) and reaches, with fluctuations, almost 3:1 in the lowest horizon. this could indicate that the proportion of fluvial sediments increases with depth compared to aeolian sediments. weathered quartz grains often have a regeneration rim that indicates several recrystallization sequences (fig. 6a3). in addition, weathered quartz and feldspar grains have no visible inclusions (figs. 6a2–3, b), whereas fresh grains are idio mor­ phic or hypidiomorphic and contain inclusions (figs. 6a–c). idiomorphic and hypidiomorphic grains, especially feldspars, figure 12. distribution of the ratio of weathered and fresh quartz grains along the pn1-5 profile. g eologia c roatica 239ružičić et al.: deciphering the pedo-sedimentary complex of the eastern adriatic coast: a case study from privlaka, croatia which are not resistant to chemical weathering, and accessory volcanic glass form part of the aeolian contribution (durn et al., 1999, 2018b). this assumption is also supported by the presence of quartz spherules formed by devitrification (fig. 6f), as well as the freshness of some grains, otherwise weatherable zircons (fig. 6l) and amphiboles such as hornblende and glaucophane (figs. 6o, p). if we focus on the dominant minerals of the thm, represented by resistant minerals such as garnet, zircon and tourmaline, the polygenetic origin of the material is confirmed by the presence of fresh idiomorphic grains with inclusions (figs. 6i, k) and allotriomorphic rounded grains without inclusions (figs. 7h, j). a comparison of the modal compositions of the privlaka pedosediment complex with the loess sections (mainly of alpi ne origin) of the island of susak (mikulčić pavlaković et al., 2011) shows a significant difference in spinel content. the susak loess is resedimented fluvial material from the po basin, and chromite is an accessory or absent component of the hmf (mikulčić pavlaković et al., 2011). however, up to 18% chromite in the thm of the privlaka section indicates a significant intake of material from sources other than the po plain. in addition to the dominant cr-rich reddish chromite, yellowish-brown cr-rich picotite? was also found, which is characteristic of basic and ultrabasic rocks and is associated with volcanic rocks, peridotites and serpentinites (fig. 6n). chromite, serpentinite (figs. 6m, n, g, 10; table 6) and serpentinized olivine basalt (fig. 9) indicate an area of origin with ultramafic rocks. wacha et al. (2019) found similar mineral phases in their study. the authors concluded that chromite grains indicate an ultramafic rock source, most likely the rocks from the inner dinarides. the presence of chert (fig. 5; table 5) and siliceous fossils (siliceous spicules of fossil sponges (fig. 6d) and fossil zonal chert spherules (fig. 6e) is the starting point for the palaeontological approach to trace the area of origin. in addition, mineralogical analysis confirmed chromium hydroxides in the palaeosol, indicating the weathering of chromium-bearing rocks such as peridotites and similar ultrabasic rocks and their alteration products (serpentinites) (schindler & mclenaghan, 2022). petrographic and modal analysis revealed that some pebbles and particles in the palaeosol represent ultramafic rocks. the chromium hydroxides are probably the product of the weathering of these rock fragments. cretaceous and eocene limestones dominate the prequaternary rocks in the study area (majcen & korolija, 1973; ilijanić et al., 2018), while eocene conglomerates, rich in spherical, rounded, dark chert pebbles, occur sporadically in outcrops in the source area. chert is almost 1000 times harder than carbonate. since the shape of the chert pebbles was the same in the source area (majcen & korolija, 1973), it cannot be used as an indicator of the intensity and distance of transportation. however, subrounded and rounded limestone fragments of the same age indicate long, intensive transport, probably with several resedimentation episodes. in contrast, angular and subangular carbonate concretions indicate a local origin and shorter transport. as such, carbonate concretions are a product of translocation and precipitation of carbonates during pedogenesis, it could be concluded that these concretions were precipitated at the bottom of that pedological profile during palaeopedogenesis (poch et al., 2024; husnjak et al., 2025), which occurred prior to sedimentation of the parent material of horizon 3. the erosion of this older palaeosol exposed these concretions, so that they were also exposed to further erosion. it can be assumed that the concretions were transported by the same mechanism as the already eroded older palaeosol and that both materials were resedimented at the investigated site. at this point, these sediments became the parent material for the new pedogenesis of horizon 3. there is a high probability that this parent material, which contained carbonate con cre tions formed during an older pedogenesis, also contained soil material from the same older palaeosol that was eroded and brought together by glacio­fluvial transport. this mechanism is described in the examples of resedimented palaeosols in continental (galović, 2014, 2016; galović et al., 2023, 2024; poch et al., 2024) and mediterranean croatia (faivre et al., 2019; husnjak et al., 2025; poch et al., 2024). there fore, we cannot assume that the degree of pedogenetic develop ment of the studied palaeosol horizon 3 reflects the climatic conditions that prevailed during its pedogenesis. indeed, the bottom sediment was exposed to pedogenesis and was de posited together with other eroded sediments. in contrast, it is merely the erosion product of a landscape from which the weathered topsoil was removed and redeposited in the studied section. based on the osl dating results, the red palaeosol in the lower part of the pedo-sedimentary complex could be as old as mis 5e (eemian) or even older. a similar age for the red palaeosol was found by durn et al. (2018a) in their study. although the osl dating results clearly demonstrate the old age of succession, we do not recommend proposing exact age estimates from it for two reasons. firstly, given the sedimentary environment of the quartz used for dating, insufficient bleaching of some or a significant proportion of the grains cannot be ruled out and may even be plausible. for this reason, we consider it safe to determine only a minimum age based on the “lower 5%” approach. secondly, the equivalent doses determined are in the high dose range for quartz (i.e., approximately between 70 – 200 gy), which could be questionable regarding the reliability of the method (obvious underestimation of age). however, it should be noted that such effects are often only observed at equivalent doses of more than 200 gy (anachitei-deacu et al., 2018). independent methods such as cosmogenic radionuclide dating could help to further constrain the age model for the privlaka succession. 4. conclusion this study contains mineralogical and sedimentological results and the first description of the quaternary succession of palaeosol and sediments in privlaka (eastern adriatic coast, croatia). the investigated sediments form a vertical, 8 m thick succession of glacio­fluvial (gf) sand resting on an underlying silty (ps) palaeosol. according to the osl dating results, the glacio­fluvial sand is either early weichselian or saalian in age, while the palaeosol most likely cannot be younger than the eemian and could even have a middle pleistocene age. g eo lo gi a c ro at ic a 240 geologia croatica 78/3 the higher caco3 content in the upper part of the pedosedimentary succession of privlaka (gf; units ii, iii and iv; sub­layers 9a to 18­3) can be attributed to the increase in the supply of the local lithogenic carbonate component (limestone fragments of sandy and silty grain size), whereas in the lower part the increase in caco3 content is partially due to the precipitation of secondary carbonates (which was also observed in the field). the results of the modal analysis show up to 18% chromite in the thm of the privlaka section, indicating a significant input of material from sources other than the po plain. in addition to the predominant cr-rich reddish chromite, yellowishbrown cr-rich picotite was also detected, which is characteristic of basic and ultrabasic rocks associated with volcanic rocks, peridotites, and serpentinites. in addition, the mineralogical analysis confirmed chromium hydroxides in the palaeosol, indicating the weathering of chromium-rich rocks such as peridotites and similar ultrabasic rocks and their transformation products (serpentinites). all the rocks and accompanying minerals mentioned indicate an area of origin with ultramafic rocks from the dinaric ophiolitic zone in the hinterland. subrounded and rounded limestone fragments of the same age indicate long, intensive glacio­fluvial transport, probably with several resedimentation episodes. however, angular and subangular carbonate concretions indicate a local origin. since such carbonate concretions are a product of translocation and precipitation of carbonates during pedogenesis, one could conclude that these concretions were precipitated at the bottom of that pedological profile during paleopedogenesis. acknowledgement this research is funded by the croatian science foundation under the project accent (ip­2020­02­3274). we are grateful to the associate editor and the reviewers for their thorough evaluations, which significantly improved the manuscript. references adamiec, g. & aitken, m. (1998): dose-rate conversion factors: update.– ancient tl 16, 37­50. anechitei­deacu, v., timar­gabor, a., thomsen, k.j., buylaert, j.­p., jain, m., bailey, m. & murray, a.s. (2018): single and multi-grain osl investigations in the high dose range using coarse quartz.– radiation measurements, 120, 124–130. https://doi.org/10.1016/j.radmeas.2018.06.008 banak, a., pavelić, d., kovačić, m. & mandić, o. (2013): sedimentary characteristics and source of loess in baranja (eastern croatia).– aeolian research, 11, 129–139. https://doi.org/10.1016/j.aeolia.2013.08.002 banak, a., pikelj, k., lužar­oberiter, b. & kordić, b. (2021): the sedimentary record of pleistocene aeolian–alluvial deposits on vrgada island (eastern adriatic coast, croatia).– geologia croatica, 74/2, 127–137. https://doi.org/10.4154/gc.2021.14 beerten, k., verbeeck, k., laloy, e., vanacker, v., vandenberghe, d., christl, m., de grave, j. & wouters, l. (2020): electron spin resonance (esr), optically stimulated luminescence (osl) and terrestrial cosmogenic radionuclide (tcn) dating of quartz from a plio-pleistocene sandy formation in the campine area, ne belgium.– quaternary international, 556, 144–158. https://doi.org/10.1016/j.quaint.2020.06.011 beerten, k., galović, l., pandurov, m., stejić, p., gajić, r., hećej, n., martinčević lazar, j., kordić, b. & pjanić, a. (2025): characteristics of late pleistocene and holocene dune activity and soil formation in the podravina, ne croatia.– quaternary research, 1–19. https://doi.org/10.1017/qua.2025.10023 behr labor­technik (2017): scm1 calcimeter for determination of the carbonate content of a soil sample. user's manual.– behr labor­technik gmbh, düsseldorf, 15 p. brewer, r. (1976): fabric and mineral analysis of soils.– krieger, huntington, new york, 482 p. cohen, k.m. & gibbard, p. (2019): global chronostratigraphical correlation table for the last 2.7 million years, version 2019. qi­500.– quaternary international, 500, 20–31. https://doi.org/10.1016/j.quaint.2019.03.009 correggiari, a., roveri, m. & trincardi, f. (1996): late pleistocene and holocene evolution of the north adriatic sea.– quaternario, 9/2, 697–704. durn, g. (1996): origin, composition and genesis of terra rossa in istria [in croatian].– unpubl. phd thesis, university of zagreb, 204 p. durn, g., ottner, f. & slovenec, d. (1999): mineralogical and geochemical indicators of the polygenetic nature of terra rossa in istria, croatia.– geoderma, 91, 125–150. https://doi.org/10.1016/s00167061(98)00130­x durn, g., wacha, l., bartolin, m., rolf, c., frechen, m., tsukamoto, s., tadej, n., husnjak, s., li, y. & rubinić, v. (2018a): provenance and formation of the red paleosol and lithified terra rossa­like infillings on the island of susak: a high­resolution and chronological approach.– quaternary international, 494, 105–129. https://doi.org/10.1016/j.quaint.2017.11.040 durn, g., rubinić, v., wacha, l., patekar, m., frechen, m., tsukamoto, s., tadej, n. & husnjak, s. (2018b): polygenetic soil formation on late glacial loess on the susak island reflects paleo­environmental changes in the northern adriatic area.– quaternary international, 494, 236–247. https://doi.org/10.1016/j.quaint.2017.06.072 durn, g., perković, i., stummeyer, j., ottner, f. & mileusnić, m. (2021): differences in the behaviour of trace and rare­earth elements in oxidizing and reducing soil environments: case study of terra rossa soils and cretaceous paleosols from the istrian peninsula, croatia.– chemosphere, 283, 131286. https://doi.org/10.1016/j.chemosphere.2021.131286 faivre, s., galović, l., sümegi, p., cvitanović, m., náfrádi, k. & horvatinčić, n. (2019): palaeoenvironmental reconstruction of the milna valley on the island of vis (central adriatic) during the late holocene.– quaternary international, 510, 1–17. https://doi.org/10.1016/j.quaint.2018.11.017 galović, l. (2014): geochemical archive in the three loess/paleosol sections in the eastern croatia: zmajevac i, zmajevac and erdut.– aeolian research, 15, 113–132. https://doi.org/10.1016/j.aeolia.2014.07.004 galović, l. (2016): sedimentological and mineralogical characteristics of the pleistocene loess/paleosol sections in the eastern croatia.– aeolian research, 20, 7–23. https://doi.org/10.1016/j.aeolia.2015.10.007 galović, l. & peh, z. (2016): mineralogical discrimination of the pleistocene loess/paleosol sections in srijem and baranja, croatia.– aeolian research, 21, 151–162. doi:10.1016/j.aeolia.2016.04.006 galović, l., frechen, m., peh, z., durn, g. & halamić, j. (2011): loess/palaeosol section in šarengrad, croatia – a qualitative discussion on the correlation of the geochemical and magnetic susceptibility data.– quaternary international, 240, 1–2, 22–34. https://doi.org/10.1016/j.quaint.2011.02.003 galović, l., husnjak, s., šorša, a. & martinčević lazar, j. (2023): evidence and mineralogical and physico­chemical properties of chernozem and chernozem­like soils in croatia.– geologia croatica, 76/3, 113–129. https://doi.org/10.4154/gc.2023.08 galović, l., šorša, a. & peh, z. (2024): modelling the paleopedological development of loess/palaeosol sections using discriminant function analysis of compositional geoscience data, case study in eastern croatia.– journal of geochemical exploration, 262, 107473. https://doi.org/10.1016/j. gexplo.2024.107473 hrn iso 10390 (2005): soil quality – determination of ph (iso 10390:2005).– croatian standard institute, zagreb. husnjak, s., galović, l., poch, r.m., martinčević lazar, j. & pjanić, a. (2025): influences of fluvial and aeolian processes on palaehttps://doi.org/10.1016/j.aeolia.2015.10.007 g eologia c roatica 241ružičić et al.: deciphering the pedo-sedimentary complex of the eastern adriatic coast: a case study from privlaka, croatia osols formation in privlaka, croatia.– geoderma regional, 40, e00942. https://doi.org/10.1016/j.geodrs.2025.e00942 ilijanić, n., miko, s., hasan, o. & bakrač, k. (2018): holocene environmental record from lake sediments in the bokanjačko blato karst polje (dalmatia, croatia).– quaternary international, 494, 66–79. https://doi. org/10.1016/j.quaint.2018.01.037 krumbein, w. & sloss, l. (1963): stratigraphy and sedimentation.– w.h. freeman and co., san francisco, 660 p. majcen, ž. & korolija, b. (1973): osnovna geološka karta sfrj 1:100 000. tumač za list zadar [basic geological map of sfry 1:100 000, zadar sheet – in croatian].– institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd. majcen, ž., korolija, b., sokač, b. & nikler, l. (1970): osnovna geološka karta sfrj 1:100 000, list zadar [basic geological map of sfry 1:100 000, zadar sheet – in croatian].– institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd. marjanac, lj. & marjanac, t. (2004): glacial history of the croatian adriatic and coastal dinarides.– in: ehlers j. & gibbard pl. (eds): developments in quaternary sciences.– part i: europe. elsevier, amsterdam, 19–26. https://doi.org/10.1016/s1571­0866(04)80053­8 marjanac, t. & marjanac, lj. (2016): the extent of middle pleistocene ice cap in the coastal dinaric mountains of croatia.– quaternary research, 85/3, 445–455. https://doi.org/10.1016/j.yqres.2016.03.006 mikulčić pavlaković, s., crnjaković, m., tibljaš, d., šoufek, m., wacha, l., frechen, m. & lacković, d. (2011): mineralogical and geochemical characteristics of quaternary sediments from the island of susak (northern adriatic, croatia).– quaternary international, 234, 32–49. https://doi.org/10.1016/j.quaint.2010.02.005 molnár, d., makó, l., cseh, p., sümegi, p., fekete, i. & galović, l. (2021): middle and late pleistocene loess-paleosol archives in east croatia: multi-proxy palaeoecological studies on zmajevac and šarengrad ii sequences.– studia quaternaria, 38/1, 3–17. https://doi. org/10.24425/sq.2020.133758 munsell soil colour charts (2013): munsell soil color charts with genuine munsell color chips.– macbeth division of kollmorgem instruments corporation, new windsor. murray, a.s. & wintle, a.g. (2003): the single aliquot regenerative dose protocol: potential for improvements in reliability.– radiation measurements, 37, 377–381. https://doi.org/10.1016/s1350­4487(03)00053­2 olley, j.m., caitcheon, g. & murray, a.s. (1998): the distribution of apparent dose as determined by optically stimulated luminescence in small aliquots of fluvial quartz: implications for dating young sediments.– quaternary science reviews, 17, 1033–1040. https://doi.org/10.1016/ s0277­3791(97)00090­5 pdf­4/minerals (2024): mdi materials data.– livermore, ca, usa. pfaffner, n., kadereit, a., karius, v., kolb, t., kreutzer, s. & sauer, d. (2024): reconstructing the eemian to middle pleniglacial pedosedimentary evolution of the baix loess–palaeosol sequence (rhône rift valley, southern france) – basic chronostratigraphic framework and palaeosol characterization.– e&g quaternary science journal, 73, 1–22. https://doi.org/10.5194/egqsj­73­1­2024 poch, r.m., galović, l., husnjak, s., martinčević lazar, j., hećej, n., ružičić, s., pjanić, a., álvarez, d., beerten, k., gajić, r., stejić, p. & pandurov, m. (2024): soil formation and environmental reconstruction of a loess-paleosol sequence in zmajevac, croatia.– catena, 247, 108507. https://doi.org/10.1016/j.catena.2024.108507 prescott, j.r. & hutton, j.t. (1994): cosmic ray contributions to dose rates for luminescence and esr dating: large depths and long-term time variations.– radiation measurements, 23, 497–500. https://doi. org/10.1016/1350­4487(94)90086­8 retallack, g.j. (2019): soils of the past: an introduction to paleopedology, 3rd edition.– blackwell science ltd., oxford, 552 p. https://doi. org/10.1002/9780470698716 schindler, m. & mclenaghan, n.w. (2022): release of chromite nanoparticles and their alteration in the presence of mn-oxides.– american mineralogist, 107/4, 642–653. https://doi.org/10.2138/am­2021­7881 shang, c. & zelazny, l.w. (2008): selective dissolution techniques for mineral analysis of soils and sediments.– in: ulery, a.l. & drees, l.r. (eds.): methods of soil analysis, part 5 – mineralogical methods, sssa book series, no. 5., soil science of america, 33–80. https://doi. org/10.2136/sssabookser5.5.c3 siart, c., hecht, s., holzhauer, i., altherr, r., meyer, h., schukraft, g., eitel, b., bubenzer, o. & panagiotopoulos, d. (2010): karst depressions as geoarchaeological archives: the palaeoenvironmental reconstruction of zominthos (central crete), based on geophysical prospection, sedimentological investigations, and gis.– quaternary international, 216, 1–2, 75–92. https://doi.org/10.1016/j.quaint. 2009.06.020 sprafke, t., schulte, p., meyer-heintze, s., händel, m., einwögerer, t., simon, u., peticzka, r., schäfer, c., lehmkuhl, f. & terhorst, b. (2020): paleoenvironments from robust loess stratigraphy using high-resolution color and grain-size data of the last glacial krems-wachtberg record (ne austria).– quaternary science reviews, 248, 106602. https://doi.org/10.1016/j.quascirev.2020.106602 újvári, g., kok, j.f., varga, g. & kovács, j. (2016): the physics of wind-blown loess: implications for grain size proxy interpretations in quaternary paleoclimate studies.– earth­science reviews, 154, 247–278. http://dx.doi.org/10.1016/j.earscirev.2016.01.006 vandenberghe, d., de corte, f., buylaert, j.p., kučera, j. & van den haute, p. (2008): on the internal radioactivity in quartz.– radiation measurements, 43, 771–775. https://doi.org/10.1016/j.radmeas.2008.01.016 velić, j., velić, i. & kljajo, d. (2011): sedimentary bodies, forms and occurences in the tudorevo and mirovo glacial deposits of northern velebit (croatia).– geologia croatica, 64, 1–16. wacha, l. & frechen, m. (2011): the geochronology of the „gorjanović loess section“ in vukovar, croatia.– quaternary international, 240/1, 87­ 99. https://doi.org/10.1016/j.quaint.2011.04.010 wacha, l., mikulić pavlaković, s., frechen, m. & crnjaković, m. (2011): the loess chronology of the island of susak, croatia.– e&g quaternary science journal, 60/1, 153–169. https://doi.org/10.3285/ eg.60.1.11 wacha, l., montanari, a., lomax, j., fiebig, m., lüthgens, c., korbar, t. & koeberl, c. (2019): last glacial maximum giant sand dunes on the island of vis, croatia.– in: koeberl, c. & bice, d.m. (eds.): 250 million years of earth history in central italy: celebrating 25 years of the geological observatory of coldigioco: geological society of america special paper, 459–470, 542 p. https://doi.org/10.1130/ 2019.2542(26) warr, l.n. (2021): ima–cnmnc approved mineral symbols.– mineralogical magazine, 85, 291–320. https://doi.org/10.1180/mgm.2021.43. wentworth, c.k. (1922): a scale of grade and class terms for clastic sediment.– journal of geology, 30, 377–392. https://doi.org/10.1086/622910 zerboni, a., trombino, l., frigerio, c., livio, f., berlusconi, a., michetti, a.m., rodnight, h. & spötl, c. (2015): the loess -paleosol sequence at monte netto: a record of climate change in the upper pleistocene of the central po plain, northern italy.– journal of soils and sediments, 15, 1329–1350. https://doi.org/10.1007/s11368­014­0932­2 žebre, m., sarikaya, m.a., stepišnik, u., colucci, r.r., yildirim, c., çiner, a., candaş, a., vlahović, i., tomljenović, b., matoš, b. & wilcken, k.m. (2021): an early glacial maximum during the last glacial cycle on the northern velebit mt. (croatia). geomorphology, 392, 107918. https://doi.org/10.1016/j.geomorph.2021.107918 web source: google maps (2025): republic of croatia. accessed at: https://www.google.com/maps/place/croatia/@44.23455,15.7881617,525170m/data=!3m 1!1e3!4m6!3m5!1s0x133441080add95ed:0xa0f3c024e1661b7f!8m2!3d45. 1!4d15.2000001!16zl20vmdfwajc?entry=ttu. accessed on: february 15th, 2025. https://www.google.com/maps/place/croatia/@44.23455,15.7881617,525170m/data=!3m1!1e3!4m6!3m5!1s0x133441080add95ed:0xa0f3c024e1661b7f!8m2!3d45.1!4d15.2000001!16zl20vmdfwajc?entry=ttu https://www.google.com/maps/place/croatia/@44.23455,15.7881617,525170m/data=!3m1!1e3!4m6!3m5!1s0x133441080add95ed:0xa0f3c024e1661b7f!8m2!3d45.1!4d15.2000001!16zl20vmdfwajc?entry=ttu https://www.google.com/maps/place/croatia/@44.23455,15.7881617,525170m/data=!3m1!1e3!4m6!3m5!1s0x133441080add95ed:0xa0f3c024e1661b7f!8m2!3d45.1!4d15.2000001!16zl20vmdfwajc?entry=ttu https://www.google.com/maps/place/croatia/@44.23455,15.7881617,525170m/data=!3m1!1e3!4m6!3m5!1s0x133441080add95ed:0xa0f3c024e1661b7f!8m2!3d45.1!4d15.2000001!16zl20vmdfwajc?entry=ttu 2022 | 75/3 | 411–420 | 2 figs. | 5 tabs. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction harbours are important for the economic and social development of coastal areas. however, they also represent anthropogenic sources of contaminant emissions cukrov et al., 2011). the increase in global trade and the consequent increase in the demand of port-services make harbours and ships key sources of wastewater input into the marine environment (shu et al., 2022). oily wastewater from shipping waste and marine activities are polluting the marine environment across the globe, and solving such a complex problem by using treatment technologies is very challenging (han et al., 2019; rađenović & medunić, 2015; sahin & vardar, 2020). wastewater emissions contain a number of variously toxic and harmful substances, that can impact the reproductive and growth characteristics of marine organisms and life and the environment in general (ternjej et al., 2013; buskey et al., 2016; wu et al., 2017; sasmaz et al., 2019). this is particularly hazardous in the case of karst-water systems (fiket et al., 2017a), which are quite sensitive to the pollution caused by wastewater effluents. karst requires careful exploitation and effective, efficient protection, mostly due to direct connections between the surface waters and highly permeable aquifers (parise et al., 2009, 2015; jebreen et al., 2018). coastal marine environments are particularly vulnerable to pollution by trace elements directly discharged into them. multidisciplinary studies of their fate in such settings are necessary due to their long-lasting cycles, and consequences for human, animal, and plant health. in this regard, sediment cores provide a historical record of activities occurring in the watershed of a distribution of sulphur, phosphorous, iron, and trace elements in bottom sediment cores, mussels and fish from the punat bay (island of krk, croatia) tatjana ivošević1*, ivan halkijević2, nina bilandžić3, katarina licht2, marija sedak3, ivica orlić4, damir bucković5 and štefica kampić5 1 university of rijeka, faculty of maritime studies, rijeka, croatia (*corresponding author: tatjana.ivosevic@pfri.uniri.hr ; tatjana.ivosevic14@gmail.com) 2 university of zagreb, faculty of civil engineering, zagreb, croatia 3 croatian veterinary institute, zagreb, croatia 4 independent researcher, krk, croatia 5 university of zagreb, faculty of science, department of geology, zagreb, croatia doi: 10.4154/gc.2022.29 abstract ships and associated anthropogenic activities release a number of contaminant elements into the marine environment which can be particularly concentrated in restricted circulatory environments including bays and marinas. one such locality is a punat bay, situated at the southern coastline of the island of krk (west croatia), which is the largest croatian marina. the aim of this study was to examine depth profiles of sulfur (s), phosporous (p), iron (fe), and trace elements (as, ba, be, cd, co, cr, cu, hg, mn, mo, ni, pb, sn, sr, ti, u, v, y, and zn) in six sediment cores (down to 20-30 cm), and from mussels and fish from punat bay, by determining their levels with icp-oes. data analysis showed that the majority of variables were elevated in a sediment core located closest a port of the marina. minimum to maximum s, p, and fe levels in sediments were as follows: 0.4-2.4%, 0.04-320 mg/kg, and 0.2-2.3%, respectively. correlations among s, p, fe, and various trace elements were mostly positive (p<0.05). trace elements were not increased in mussels and fish. this paper shows that the punat marina has only a limited impact on the environmental status. several potentially toxic trace elemens (pb, cu, etc.) were found to be elevated in a sediment core located closest to the marina. particular bay or estuary (cindrić et al., 2015; fiket et al., 2017a). namely, sedimentary geochemical composition enables an estimate to be made of background levels and changes in input over a period of time (kang et al., 2022). one such environment is the croatian punat marina (fig. 1), which is among the leading nautical tourism centres on the croatian coast. it is the oldest and one of the leading marinas in the adriatic, also containing a shipyard. ports are important transport hubs that contribute to the social and economic development of coastal areas with an impact on commerce, tourism and often, with potential negative effects on pollution and health. valković et al. (2007) investigated the punat locality and discovered anthropogenic loads of cu, zn, and pb from the local marina and the shipyard. the main sources of contamination from the chemical compositions of the sediments in the punat bay were antifouling paints. these contaminations were reflected in the elevated concentrations of zn, cu, and pb in the upper sediments in the vicinity of marina working area and the shipyard. the contamination of the coastal environments with sn completely originates from tributyltin (tbt) antifouling paints. furdek turk et al. (2020) determined that tbt input via antifouling paints resulted in high enrichment of coastal punat sediments with inorganic sn. oreščanin et al. (2002) gave a detailed account of the evaluation of the anthropogenic influence on the chemical compositions of the sediments in punat bay. they determined that the antifouling paints were the main source of contamination which was reflected in the elevated levels of zn, cu, and pb in the four uppermost centimetres of fine-grained article history: manuscript received june 17, 2022 revised manuscript accepted september 02, 2022 available online october 26, 2022 keywords: sulfur; phosporous; iron; sediment cores; mussels; marina; contamination g eo lo gi a c ro at ic a geologia croatica 75/3412 sediments in the vicinity of the marina working area and the shipyard. their results also showed the influence of the marina on distant parts of punat bay as a consequence of the morphology and the climate conditions influencing the efficiency of the cleaning mechanisms. as global consumption of seafood rises (fox et al, 2018), it’s important to research the potential hazardous trace element content, especially of non-essential metals pb, cd, as and hg in fish samples and wild mussels. trace elements concentrations of zn, cu, as, pb, cd and hg in wild blue mussels collected from 2005 to 2007 were measured from the coastal areas of the southeastern adriatic (marković et al, 2012). the obtained data for cd and pb indicated that metal levels from the montenegrin coastal areas were much higher than the concentrations reported for other adriatic and ionian sea areas (cardellicchio et al., 2008; kljaković-gaspić et al., 2006; klakovićgaspić et al., 2007). against the toxicities of cd and pb, zinc is one of the essential trace elements for humans and its toxicity is rare. the concentrations of zn in montenegrin mussels were higher than ones in the ionian sea in southern italy (cardellicchio et al., 2008) but lower than those sampled from the eastern adriatic coast (kljaković-gaspić et al., 2006), or from the mali ston bay coast (klaković-gaspić et al., 2007). more recently, trace elements in blue mussels including al, fe, zn, cu, ni, mn, cr, as, pb, cd, etc. were measured in the gulf of trieste (bajc & kirbiš, 2019), raša bay (ivošević et al, 2022), šibenik bay (bogdanović et al, 2014) and boka kotorska bay (perošević et al., 2018). the highest measured concentrations of al and fe were in raša bay. these concentrations were up to five times higher than the concentrations of these elements in other sites. other measured trace element concentrations were differences within 30% of earlier measurements of the same elements. the pb and cd concentrations did not exceed prescribed values for pb of 1.5 mg/kg ww, and for cd of 1 mg/kg ww (regulation, 2006). different fish tissues such as muscle tissue or liver are commonly used as indicators of the degree of contamination of the marine environment by hazardous trace elements. cadmium and lead were determined in the muscle tissue of fish species sampled in 1995 from the eastern adriatic. in the muscle tissue, cd and figure 1. map of the study area. g eologia c roatica ivošević et al.: distribution of sulphur, phosphorous, iron, and trace elements in bottom sediment cores, mussels and fish from the punat bay ... 413 pb concentrations were among the range of concentrations for fish samples in the mediterranean and these results provided no proof of the general pollution of the adriatic (kljakovićgašpić et al, 2002). salimanec grgec et al (2022) reported total hg, total as and se in fish samples (e.g. sparus aurata) available in a croatian market which were characterized by their origin from the adriatic sea. wild-caught fish had generally higher levels of as (11 times) and hg (29 times) and se (1.6 times) than farmed fish of the same species. the aim of this study was to examine the depth profiles of sulfur (s), phosphorous (p), iron (fe), and trace elements (al, as, ba, be, cd, co, cr, cu, hg, mn, mo, ni, pb, sn, sr, ti, u, v, y, and zn) in six sediment cores (down to 20-30 cm), wild blue mussels and fish sampled and caught in punat bay, in the context of possible anthropogenic influences on the marina’s environment and other port and tourism activities such as boat painting, domestic waste etc. 2. materials and methods 2.1. geological characteristics of the study area the island of krk is the northernmost large island in the mediterranean, and is located in kvarner bay. it is the largest island of the adriatic sea with a surface area of 409.9 km2. it belongs to the western part of the outer dinarides, composed mainly of cretaceous shallow-water carbonates of the adriatic carbonate platform (vlahović et al., 2005). these deposits are overlain by palaeogene carbonate ramp shallow-marine carbonates in certain locations, and later by flysch (deep-sea trough marls in alternation with carbonate conglomerates, arenites, and siltstones), which formed when ramp carbonate production couldn’t keep up with subsidence (ćosović et al., 2008; gulam et al, 2014). the youngest palaeogene deposits at krk island are represented by the so-called jelar carbonate breccias formed by poly-phase tectonic fracturing of the apical parts of the overturned anticline, resulting in the crushing of clasts and collapse into a complex system of deep fractures largely without surficial transport (vlahović et al., 2007). the punat bay study area’s immediate environment is made up of upper cretaceous and palaeogene to quaternary deposits (šušnjar et al., 1970). the west and south coast of punat bay is predominantly built of microcrystalline dolomite with frequent intercalations of fossiliferous limestone beds containing numerous foraminifera species, e.g., nummoloculina heimi bonet, nezzazata simplex omara as well as with frequent occurrences of mollusc shells such as chondrodonta and nerinea, indicating a cenomanian/lowermost turonian age. these carbonates have a different degree of fissuring and karstification and form the typical karstic landscape. the east coast of the bay is covered by pliocene to quaternary talus breccias composed of silty clay and carbonate fragments and a little further to the east, by the oligocene jelar breccias. 2.2. sampling of bottom sediments sampling locations of marine sediments in punat bay were selected to be at a depth of 3 to 4 m due to a home-made core sampler dimension. its main elements are a plastic pipe with a diameter of 9,5 cm and a non-return valve that prevents the loss of sediment when drawing the pipe from the sea. the lengths of samples collected with this sampler were typically in the range of 30 to 60 cm. the six core samples were collected during october 20th, 2020 sampling excursions. the sampling locations are shown on the map in figure 1 and are labelled pn1-pn6 in a clockwise sequence within the lagoon. the seawater depths at these locations vary from 3.5 m (pn1, pn2) to 4 m (pn3, pn4, pn5, pn6). immediately after their collection, each core sample was cut into 1 cm segments for the first 10 cm, and then about 10 cm sections below 10 cm core depth using a specially designed guillotine in order to obtain the concentration depth profiles of the pollutants in the sediment. 2.3 sampling of biota wild blue mussels (m. galloprovincialis) were sampled at 1 m below sea level where the depth of punat bay, is about 3m, on the 26th january 2021. sampling sites are numbered m1 to m7 on figure 1. around 0.5 kg of mussels were collected at each site, placed into polyethylene bags with seawater and transported to the laboratory for determination of residues at the croatian veterinary institute in zagreb. the mussel samples were first unshelled and the soft tissues were pooled and thoroughly rinsed with deionised water to remove extraneous impurities. the whole mussel tissues were homogenised in a blender and stored at − 20 °c until analysis. the fish samples (sparus aurata and lophius piscatorius) were collected in punat bay close to the sediment sampling sites pn1 on the 26th january 2021. the fish were beheaded, gutted, washed, and filleted. only the edible portions were utilized for the analysis. fish fillets (tissue) were carefully removed from the fish bones without any contact with guts and roes. this was to prevent any contamination being introduced to fish tissue. fish fillet was also homogenised in a blender and stored at − 20 °c until analysis. 2.4. analytical work 2.4.1. sediment samples all glassware and containers used were previously cleaned by soaking for 48 hours in 10% hno3 solution and rinsed with highpurity water before use. sediment core samples, were sieved to <0.063 mm and weighed. afterwards, 5 ml of hno3 and 15 ml of hcl were added. a wet digestion of the samples was performed on a hot plate for 4 h. it should be noted that this is not a complete digestion method (potts, 1992). the samples were filtered through a blue coloured filter paper and the precipitate was washed with distilled water. after the cooling step, the filtrate was quantitatively transferred to a 50 ml volumetric flask and filled to the mark with distilled water. an inductively coupled plasma optical emission spectrometer (icp-oes) was used for elemental analysis. all measurements were performed using the agilent 5900 svdv icp-oes system equipped with a sea spray concentric glass nebulizer and a double-pass glass spray chamber. simultaneous axial and radial viewing mode was used for element determination, while fitted background correction and 3 replicates were used to measure the analytical signal. quantification was performed by linear weighted regression of the calibration curves. the appropriate emission lines were selected using the intelliquant screening feature in the icp expert software, which allows full spectrum measurement of each sample and determines which wavelengths provide the best result. calibration standards (0.01, 1, 10 µg/l) were prepared by diluting the 10 µg l-1 stock multi-element standard solutions (71a and 71b, inorganic ventures, usa) in 2% hno3 and 1% hcl. for quantification of concentrated elements, samples were diluted 10-fold and measurements were reg eo lo gi a c ro at ic a geologia croatica 75/3414 (65%). wet digestion of the samples was performed using a highpressure microwave oven multiwave 3000 (anton paar, graz, austria), in three steps: i) 2.5 minutes at 500 w; ii) 20 minutes at 1000 w, and iii) 30 minutes at 1200 w. following the cooling step, the digested clear solution was quantitatively transferred to peated. all solvents and reagents used were of analytical purity and were manufactured by vwr chemicals bdh (usa). 2.3.2. fish and mussels homogenized tissue samples (0.5 g) were weighed into a teflon liner with the addition of 3 ml distilled h2o and 2.5 ml hno3 table 1. basic statistical parameters of analysed variables in six sediment cores (pn1-6). (the concentrations are presented in mg/kg. the concentrations of fe and s are presented in g/kg*) as ba cd cr cu fe* hg mn mo ni p pb s* sn u v zn n 12 12 12 12 12 12 12 12 12 12 12 12 12 4 12 12 12 min 0.160 18.1 0.860 14.0 9.04 3.05 0.060 61.2 3.40 5.30 0.090 2.37 3.89 0.500 2.38 11.6 27.1 max 10.5 28.0 1.88 21.1 46.2 4.93 4.59 81.5 15.8 13.5 111 12.9 12.8 2.96 32.2 21.0 111 mean 4.25 23.0 1.33 17.2 25.3 3.96 1.39 70.3 7.08 9.72 40.0 7.84 7.17 1.55 14.5 17.2 67.3 stdev 3.68 2.58 0.370 1.70 11.2 627 1.37 6.27 3.94 3.09 48.4 4.47 3.65 1.04 10.6 2.88 24.3 median 3.52 23.2 1.25 17.2 26.1 3.80 1.13 70.2 5.93 10.9 12.3 8.80 4.94 1.37 14.9 17.0 65.4 25 prcntil 1.03 21.0 0.955 16.3 14.8 3.46 0.193 64.4 3.83 5.87 0.670 2.52 4.69 0.665 3.95 15.2 49.9 75 prcntil 6.45 24.8 1.64 17.7 33.8 4.65 2.05 76.0 9.77 11.75 103 12.0 11.7 2.62 22.7 20.3 84.8 coeff. var 86.7 11.2 27.9 9.93 44.1 15.8 99.0 9.12 55.6 31.7 121 57.0 50.9 67.1 72.9 16.7 36.1 n14 14 14 14 14 14 14 14 14 14 14 14 14 3 14 14 14 min 0.5 21.4 0.910 21.8 14.8 6.61 0.180 76.0 2.94 13.1 0.220 4.11 5.53 2.51 4.71 25.0 40.3 max 15.6 33.1 2.05 46.4 60.8 10.1 3.89 117 27.3 47.2 144 32.1 22.4 20.5 27.5 50.0 167 mean 6.99 24.9 1.32 32.5 30.2 8.51 1.42 93.6 14.5 20.4 38.5 13.2 11.2 9.19 12.8 37.5 76.4 stdev 4.55 3.610 0.320 5.76 14.8 1.18 1.22 11.3 7.75 8.25 50.7 8.58 5.67 9.86 7.11 6.27 35.4 median 8.74 23.7 1.29 31.4 26.4 8.32 1.04 9.15 14.3 18.4 122 11.5 8.83 4.55 9.75 38.2 68.7 25 prcntil 2.68 22.0 1.04 29.7 17.6 7.47 0.25 85.4 7.66 16.5 43.9 5.5 8.17 2.51 7.66 33.4 46.4 75 prcntil 9.74 26.5 1.52 34.2 40.3 9.65 2.46 101 21.7 20.7 96.9 16.0 13.4 18.5 19.8 40.0 92.3 coeff. var 65.0 14.5 2.47 17.7 48.9 13.8 86.1 12.02 53.6 40.5 131.8 65.1 50.4 107 55.4 16.7 46.3 n 13 13 13 13 13 13 13 13 13 13 13 13 13 4 13 13 13 min 1.00 18.4 0.900 29.9 13.3 7.00 0.060 76.8 5.83 17.1 1.24 6.30 6.40 1.56 6.05 26.1 42.8 max 11.5 34.9 4.49 51.1 52.8 11.8 2.78 106 27.7 30.0 180 41.8 24.3 2.57 25.3 51.9 163 mean 5.62 26.7 2.30 39.8 28.0 9.41 1.06 92.7 15.5 21.7 110 16.7 13.4 1.95 14.0 42.5 93.5 stdev 3.370 6.4 1.160 5.50 14.72 1.31 0.966 9.6 7.6 3.39 62.50 10.3 5.43 0.470 6.1 7.0 40.4 median 4.34 26.0 2.31 39.5 21.7 9.26 0.920 91.0 16.5 20.9 129 11.8 11.7 1.84 11.7 41.3 82.5 25 prcntil 3.02 20.3 0.975 36.0 15.8 8.39 0.225 83.7 7.71 19.6 67.1 10.1 9.47 1.57 9.80 38.4 61.1 75 prcntil 8.38 33.7 3.11 41.9 41.8 10.4 1.86 100 21.8 22.6 146 24.4 18.4 2.45 18.3 48.6 138 coeff. var 59.9 23.9 5.04 13.8 52.6 1.39 90.6 10.3 48.6 15.7 56.7 60.8 40.5 2.43 43.6 16.6 43.2 n -pn4 12 12 12 12 12 12 12 12 12 12 12 12 12 8 12 12 12 min 0.39 19.9 0.82 18.7 13.0 5.51 0.030 70.7 2.93 8.91 0.040 4.51 7.20 0.500 2.95 21.1 39.5 max 13.2 40.6 4.43 33.0 386 9.80 3.00 85.0 47.8 21.7 156 37.8 24.5 9.91 24.1 46.4 121 mean 4.96 24.7 2.39 26.4 57.7 7.10 0.946 75.6 21.1 15.6 79.2 11.8 13.7 2.41 10.3 29.8 89.0 stdev 4.45 5.64 1.00 4.05 104 1.39 1.21 4.3 16.50 3.6 51.0 9.1 6.32 3.18 6.24 8.35 27.9 median 2.61 22.9 2.61 27.3 24.4 6.79 0.295 75.7 16.9 15.6 93.4 8.67 11.7 1.20 9.33 26.1 88.5 25 prcntil 1.36 21.6 1.44 22.7 17.3 5.91 0.053 71.1 5.00 12.30 22.5 6.63 7.68 0.523 5.14 23.6 71.8 75 prcntil 9.62 27.4 2.87 29.1 41.9 8.17 2.35 77.5 34.4 18.6 112 13.3 19.3 2.94 15.0 37.1 117 coeff. var 89.7 23.0 42.2 153 18.1 196 128 5.69 78.5 23.4 64.4 77.3 46.1 132 60.4 28.0 31.3 n 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 min 1.26 26.0 1.07 12.0 11.7 3.82 0.27 66.9 1.85 12.4 0.270 0.060 4.97 12.4 4.37 52.4 max 10.3 44.0 4.97 24.2 34.9 8.71 3.68 147 16.7 55.1 123 11.4 17.9 26.1 7.40 103 mean 5.86 34.8 2.35 19.1 20.7 5.47 1.83 98.1 11.4 19.2 25.1 3.28 8.22 18.4 5.57 74.6 stdev 3.24 5.6 1.41 3.6 7.4 1.44 1.15 22.5 4.4 10.9 38.4 3.34 3.21 7.1 3.74 12.8 median 5.59 35.8 1.46 19.7 17.6 4.84 1.74 99.1 12.1 16.7 8.73 2.46 7.51 18.7 5.47 69.8 25 prcntil 2.57 29.6 1.34 17.0 14.9 4.56 0.73 80.9 8.12 14.5 25.5 0.295 6.65 15.6 4.94 68.5 75 prcntil 9.17 38.5 3.38 22.1 26.7 6.19 2.84 111 15.4 18.1 34.8 5.00 8.91 20.2 6.14 78.5 coeff. var 55.4 15.9 60.0 19.0 35.7 2.65 6.29 23.0 38.2 57.2 153 102 39.0 20.3 16.1 17.2 n 4 4 4 4 4 4 4 4 4 4 4 4 4 1 4 4 4 min 12.1 118 1.10 57.6 243 18.1 0.260 148 2.78 31.0 0.370 101 10.0 12.0 9.46 55.4 410 max 21.8 435 3.83 70.4 519 23.2 3.97 184 6.05 48.8 320 372 22.2 12.0 20.6 67.6 586 mean 17.4 229 3.13 66.0 384 20.4 2.79 162 4.70 43.0 81.3 209 13.5 12.0 16.5 60.8 472 stdev 6.3 115.0 1.35 24.8 142.3 7.64 1.390 61.0 1.72 15.5 127.0 97.8 5.48 0 6.11 23.1 171.0 median 17.8 181 3.79 67.9 387 20.2 3.47 159 4.98 46.0 2.56 182 10.8 12.0 18.0 60.0 446 25 prcntil 13.3 130 1.77 59.9 267 18.5 10.6 149 3.30 34.4 0.728 116 10.1 12.0 11.1 56.5 411 75 prcntil 21.1 376 3.82 70.1 498 22.6 3.85 179 5.81 48.5 240 330 19.4 12.0 19.4 65.8 560 coeff. var 23.4 61.8 43.2 87.6 31.1 10.5 61.1 10.0 29.3 19.1 196 55.7 4.3 0 31.0 83.4 17.5 pn 5 pn 6 elements pn 1 pn 2 pn 3 pn 4 g eologia c roatica ivošević et al.: distribution of sulphur, phosphorous, iron, and trace elements in bottom sediment cores, mussels and fish from the punat bay ... 415 a 50 ml volumetric flask and filled up to the mark with ultra-pure water. because on-line introduction of an internal standard by peristaltic pump was carried out, the internal standard solution must be prepared separately from the sample and the calibration curve standard solutions. the inner diameter of the internal standard introduction tubing is much smaller than the inner diameter of the sample introduction tubing and so the uptake rate of the internal standard solution is about 1/20 of the sample uptake rate. a mixture of internal standard solution (istd) of 200 ppb containing in, bi, and sc (inorganic ventures, blacksburg, va, usa) was added on-line using the standard istd mixing tee connector. the fish and mussel samples were analysed after microwave digestion with nitric acid. the decomposed samples were diluted with demineralized water and the final volume content of nitric acid was 5%. also, calibration standards were done in 5% nitric acid. concentrations of htes in fish and mussels were determined by inductively coupled plasma with a mass detector agilent icp-ms model 7900 (agilent, palo alto, ca, usa). high purity argon was used throughout (99.999%, white martins, brazil). calibration of the instrument was done using certified standards of 99.99% purity for all elements (se, cd, pb, cu, zn) at a concentration of 10 mg/l (environmental calibration standard, agilent technologies, usa). data quality was checked by analysis of the recovery rate using certified reference materials: mussel tissue (2976, nist, usa) and dogfish muscle (dorm-4, national research council, canada). we obtained 15 element concentrations v, cr, mn, co, ni, cu, zn, as, se, ag, mo, cd, ba, pb and hg in white fish and 13 htes (without ag and hg) in wild blue mussels and different sizes of mussels. all data are expressed in mg/kg on a wet basis (w.wt.). 2.5. data analysis data analysis was conducted with the free past software (hammer et al., 2001). it included calculations of basic statistical parameters, and nonparametric kendall’s tau correlation coefficients, and kruskal–wallis test (level of significance was lower than 0.05). 3. results and discussion 3.1. element levels in bottom sediment cores basic statistical parameters of analysed variables in six sediment cores are shown in table 1. the range of values of s, p and fe across all cores are as follows: 0.4-2.4%, 0.04-320 mg/kg, and 0.2-2.3%, respectively. they are either comparable to or lower than the respective values reported by brunović et al. (2019) as follows: 0.1-4.3%, 100-1000 mg/kg, and 0.6-5.2%. the authors interpreted high s values as resulting from the development of a restricted and oxygen poor water body (island of cres). reimann & de caritat (1998) report natural s levels in stream overbank sediments (marine bottom sediments are not included in the publication) at 0.01%. mu et al. (2021) report fractionation and availability of p in sediments of xiaowan and nuozhadu reservoirs in the middle and lower reaches of the lancang river (china). their p levels ranged 490-550 mg/kg, which is slightly above the maximum p value in punat bay in the pn6 core (320 mg/kg, table 1). they also interpreted sediment column p levels in the context of the release of fe and s from reactive phases. the behaviour of fe, mn, and p in sediments mostly depends on redox processes, and p (and s as well) mostly originates from the breakdown of organic matter, which also affects redox conditions (salomons & foerstner, 1984). the same is true for s levels, brunović et al. (2019) interpreted high mo values (0.145 mg/kg) as being due to oxygen depleted conditions. since mo values in this study ranged between 1.4-48 mg/kg, a similar interpretation could be ascribed to the punat bottom sediments as s and mo levels (table 1) are fairly comparable with their respective values in the paper by brunović et al. (2019). this study reports higher cu (9-519 mg/kg) and pb (0.1-372 mg/kg) values than respective ones in brunović et al. (2019), i.e., 5.3-33.2 mg/kg, and 5.8-86.8 mg/kg. also, punat sediment cu and pb levels are much higher than their respective values (up to 64 mg/kg and 74 mg/kg) found in sediment polluted with fly and bottom ash (oreščanin et al., 2005a). herewith, the punat sediments of the pn6 core (fig. 1) can be considered as being polluted with cu and pb as the levels of both elements naturally are mostly well below 100 mg/kg in adriatic sediments (fiket et al., 2021; medunić et al., 2018), and below 50 mg/kg in river sediments (oreščanin et al., 2005b). mikulić et al. (2004) reported four sources of cu, zn and pb in sediments, not only the antifouling paints, but also arising from traffic, long-range transport of aerosols and eroded materials. also, a few samples had quite high hg levels (3-4.6 mg/kg) that are slightly less than the maximum hg value (6.5 mg/kg) in the sava river sediment, polluted by weathering of hg-pb-ba ores (pavlović et al., 2004). according to pavlović et al. (2005), such high levels of hg represent on average a 100-fold increase with respect to clean sediments. stanković et al. (2014) report an hg max value of 0.1 mg/kg in surface adriatic sediments. levels (mg/kg) of as, ba, cr, mn, mo, ni, sn, u, v, and zn in raša bay sediments are reported by fiket et al. (2021) as follows: 6, 150, 120, 500, 2, 50, 0.3, 3, 70100, and 60-90, respectively. respective levels (mg/kg) in this study were the following: 0.2-22, 18-434, 5-70, 16-183, 1.4-48, 5.3-55, 0.5-20, 0.3-32, 5.1-68, and 27-586. their comparison clearly shows that the punat sediments are slightly enriched in as, ba, cu, mo, pb, sn, u, and zn, likely due to the influence of anthropogenic activities related to the marina. furthermore, table 1 shows the largest rsd values for as, cu, hg, p, pb, sn, and u as a consequence of anthropogenic processes, which usually result in high rsd values of trace elements in the environment, causing their skewed distributions (reimann & filzmoser, 2000; pavlović et al., 2004, 2005). based on p values 0.003 and 0.01, kruskal-wallis test confirmed for s and p, respectively, that six sediment cores were mutually significantly different. similar p values were found for as, cr, cu, fe, mo, ni, pb, ti, v, and zn as follows: 0.03, 8e-10, 0.002, 1e-08, 0.001, 2e-07, 1e-06, 8e-07, 3e-09, and 0.002, respectively. such low numbers are indicative of a very strong difference among the sediment cores. based on mann-whitney pairwise test, either all six sediment cores were mutually significantly different or cores pn1-5 were significantly different from the pn6 core. analysed variables were elevated mostly in core pn6, situated closest to the ships in the marina (fig. 1), as shown in fig. 2. it presents a comparison of variable levels in sediment cores, and this is fairly in accordance with the aforementioned results of the kruskal-wallis test. generally, box-plot patterns are fairly similar to each other (a convex ‘curve’ pn1-5 that peaks in pn6), except for u where in this case the null hypothesis was accepted (no difference among groups). interestingly, u levels in the punat sediments are fairly increased in all six sediment cores compared with u levels in the adriatic sediments that are mostly less than a few mg/kg (fiket et al., 2021; medunić et al., 2018). from fig. 2 it can be assumed that mostly natural geochemical prog eo lo gi a c ro at ic a geologia croatica 75/3416 figure 2. descriptive statistical parameters for concentrations of selected elements obtained in sediment cores (pn1-6). g eologia c roatica ivošević et al.: distribution of sulphur, phosphorous, iron, and trace elements in bottom sediment cores, mussels and fish from the punat bay ... 417 cesses have governed the distribution of the analysed variables in the punat bottom sediments at the sites pn1-5, while site pn6 has been adversely impacted by the port and marina. kendal tau correlation coefficients (p<0.05) among analysed variables can be found in table 2. primarily, the focus was put on relationships among s as a fingerprint element of the presence of organic matter, and the rest of variables. it is well established that the organic fractions of sediments act as reservoirs of trace elements (pavlović et al., 2004; oreščanin et al., 2005b), especially potentially toxic ones such as ba, cr, cd, cu, ni, pb, v, and zn. correlations in table 2 are mostly positive, and they can be interpreted by various natural physico-chemical processes in sediments (mihelčić et al., 1996; miller et al., 1998; pavlović et al., 2005). it is noteworthy that s and hg are mostly negatively correlated, and this might be explained by possible discrete hg particles. mercury is commonly lost to the environment as hg0 is characterized by low mobility and high density (lacerda et al., 1995; miller et al., 1998), and therefore hg distribution in aquatic environments is mainly controlled by physical and gravimetric parameters. 3.2. element levels in mussels trace elements can accumulate in aquatic organisms such as fish and mussels which could be a potential risk to the ecosystem. people consuming seafood could be unintentionally exposed to trace elements with potential danger to their health. concentrations of 16 trace elements in blue mussel samples (mytilus galloprovincialis) sampled in punat bay are shown in table 3. their average concentrations decrease in the following order: fe>al>zn>cu>as>mn>mo>se>v>pb>cr>ba>ni>co> cd>ag. the levels of fe, al, zn, cu, mn and as were higher than 1 mg/kg ww (ww-wet weight), and concentrations of the remaining elements were lower than 1 mg/kg ww. according to the croatian regulation (2006), the maximum permissible limits set for cd (1 mg/kg ww) and pb (1.5 mg/kg ww) were higher than the concentrations of cd and pb in the punat bay wild mussels. as can be seen from table 4, the mean concentrations of pb, zn and cd in punat bay wild mussels were lower than in the mussel samples in raša bay (ivošević et al., 2022), gulf of trieste, seča (bajc & kirbiš, 2019), šibenik bay (bogdanović et al., 2014) or boka kotorska bay (perošević et al., 2018). the mean concentrations of cu and mo in the punat mussels were higher than those in the selected sites. mean cu and mo concentrations were 1.5 higher than corresponding concentrations sampled in raša mussels (ivošević et al., 2022). further, the mean cu concentration in mussels were also 3 times higher than in trieste mussels (bajc & kirbiš, 2019) and in boka kotorska mussels (perošević et al., 2018). table 2. kendal tau correlation coefficients (p<0.05) among analysed variables (pn1-6 are sediment cores; +, and signs mark positive and negative correlations (>0.7), respectively). pn1 pn2 pn3 pn4 pn5 pn6 + + + + + + correlations (p<0.05) with sulfur: al, ba, cr, cu, fe, mn, p, v hg cu, fe, p, zn be, cd, hg, k ba, co, cu, fe, mn, ni, p, pb, v, y, zn co, fe hg ba, co, ni be, hg, u as-be al-cr fe-cu mn-cu mn-fe as-co cu-mo p-u p-cu p-fe pb-cr p-zn cr-ni p-cu pb-cu p-zn pb-mo ni-cr cd-hg mn-fe pb-cd pb-p p-sr cu-fe pb-ba table 3. concentrations of trace elements in wild blue mussels (mg/kg w. w.) from seven locations. essential elements are listed above the drawn line, and non-essential ones are listed below it. c(mg/kg w.w.) m1 m2 m3 m4 m5 m6 m7 fe 34.2 27.3 25.9 22.9 12.3 11.1 96.2 zn 11.1 15.7 14.6 17.5 12.1 9.95 12.0 se 0.353 0.404 0.309 0.262 0.248 0.242 0.289 cu 3.10 3.74 4.36 5.34 2.89 2.37 10.9 ni 0.115 0.140 0.074 0.155 0.069 0.066 0.074 mn 2.33 1.36 0.71 1.49 0.689 0.762 1.42 cr 0.189 0.203 0.109 0.108 0.078 0.058 0.264 co 0.066 0.066 0.056 0.081 0.055 0.044 0.043 mo 0.492 0.585 0.427 0.318 0.200 0.152 0.089 v 0.343 0.201 0.124 0.139 0.076 0.062 0.110 al 42.1 31.8 17.7 25.3 11.2 6.24 21.2 as 2.67 2.42 2.65 2.00 1.91 1.76 1.69 ba 0.258 0.137 0.117 0.136 0.051 0.029 0.079 cd 0.029 0.038 0.034 0.032 0.025 0.023 0.028 ag 0.004 0.009 0.006 0.004 0.004 0.002 0.012 pb 0.168 0.165 0.157 0.276 0.097 0.075 0.078 g eo lo gi a c ro at ic a geologia croatica 75/3418 cooper is toxic when it is present in higher concentrations than those necessary for organisms (maria & bebianno, 2011). higher concentrations of cu in punat bay mussels could indicate a nanoform of copper from various applications such as liquid filtration, wood preservation, bioactive coating, etc. (gomes et al., 2011) used for boat and yacht maintenance. the concentrations of as in punat mussels were 1.5 and 1.8 times lower than in the raša mussels and the trieste mussels. the concentrations of pb were similar in mussel samples from three sites; punat bay, raša bay and the gulf of trieste, but concentrations of pb were 3.2 and 7.3 times lower than in the boka kotorska mussels (perošević et al., 2018) and the šibenik mussels (bogdanović et al., 2014). the obtained mean cd concentration were from 4.6 to 6.6 times lower than in other sites. lead and cd-contaminating compounds in water and sediments can be related to commercial ship, recreational boat traffic, etc. (nowrouzi et al., 2012). these (pb and cd) could be because lower intensity of maritime traffic and lower in-port activities in punat bay than other ports. the concentrations of cr and zn in punat mussels were lower than in raša bay and gulf of trieste. this could indicate smaller quantities of sewage water because elements such as cr and zn are related in sewage sludge (senesi et al., 1999). 3.3. element levels in fish the concentrations of 15 trace elements were obtained from muscle tissues of sparus aurata and lophius piscatorius (table 5). from the obtained data, the average concentrations decrease in the following order: fe>zn>al>as>se>cu>ni>mn> cr>ba>hg>mo>v>pb>co>cd>ag>sb. the cd and pb were lower than recommended concentrations in regulation. this analysis was undertaken to examine the presence of htes consisting of essential elements: fe, zn, se, cu, ni, mn, cr, co, mo and v, and non-essential elements: al, as, hg, pb, cd, ba, ag and sb. non-essential elements were considered pollutants because of their toxicity in relatively small quantities (rosli et al., 2018). the measured trace element concentrations in table 5 (except se) were higher in wild gilt-head breams (lat. sparus aurata) up to 21 times higher than in anglerfish (lat. lophius piscatorius). the v concentrations were 21 times higher in gilt-head breams than in anglerfish, pb and cr concentrations were 8 times higher, ba were 4.5 times higher, than mn, ni, mo, as and cd were 2 times higher in gilt-head seabreams. so, it seems from the results obtained that wild gilt-head breams accumulated more trace elements than anglerfish. vanadium in trace amounts is beneficial to normal cell growth, and it is an essential element. toxicity arises when vanadium concentrations are increased to a higher level. vanadium porphyrin is found in the petroleum and bitumen extracted from table 4. comparison of concentrations (mean, min, max) of trace elements in wild blue mussels (mg/kg ww) with literature data from different sites in adriatic sea (a ivošević et al., 2022; b bajc & kirbiš, 2019; c bogdanović et al., 2014; d perošević et al., 2018; e – regulation, 2006). c /(mg/kg w.w.) mean min max raša baya gulf of triesteb šibenik bayc boka kotorska bayd cro. regulatione fe 32.8 11.1 96.2 175.7 42 55 zn 13.3 10.0 17.5 14.3 20 14.9 se 0.301 0.242 0.404 1.42 cu 4.67 2.37 10.9 3.65 1.3 1.49 ni 0.099 0.066 0.155 0.669 0.4 0.36 mn 1.25 0.69 2.33 4.21 1.80 1.59 cr 0.144 0.058 0.264 0.555 0.36 0.22 co 0.059 0.044 0.081 0.174 0.2 0.13 mo 0.323 0.089 0.585 0.215 v 0.151 0.062 0.342 0.898 al 22.2 6.21 42.1 205.1 81.5 as 2.15 1.69 2.63 3.16 4.0 2.29 pb 0.145 0.075 0.276 0.197 0.1 1.06 0.46 1.5 ba 0.115 0.029 0.258 0.694 0.23 cd 0.030 0.023 0.038 0.140 0.2 0.19 0.17 1 ag 0.006 0.002 0.012 sampling year 2021 2020 2015 2011 2015 table 5. levels of analysed trace elements in fish samples caught in 2021 (a ivošević et al., 2022, b – regulation, 2006). c (mg/kg ww) sparus aurata lophius piscatorius s. aurata rašaa regulationb fe 7.85 5.53 9.07 zn 4.86 4.77 4.87 se 0.356 0.465 0.417 cu 0.401 0.318 0.343 ni 0.0171 0.00873 0.231 mn 0.317 0.110 0.217 cr 0.103 0.0130 0.0567 co 0.00680 0.00581 0.00653 mo 0.00481 0.00154 0.0106 v 0.2558 0.0115 0.0103 al 5.09 3.34 2.70 as 11.3 6.39 0.883 ag 0.00021 0.00030 0.00093 cd 0.00099 0.00042 0.0012 0.3 ba 0.107 0.0230 0.0530 pb 0.0444 0.00532 0.00783 0.2 l/cm 25 30 20-30 g eologia c roatica ivošević et al.: distribution of sulphur, phosphorous, iron, and trace elements in bottom sediment cores, mussels and fish from the punat bay ... 419 shales, and it can be considered as an indicator of marine oil pollution (colina et al., 2005). abdolahpur monikh et al. (2011) suggested that the combustion of fossil fuels and the residual fuel oil contributes to vanadium accumulation in sediments and fish. vanadium mean concentrations in the punat sediments presented in table 1 vary between 10.3 and 42.5 mg/kg ww which were up to nine times lower than the obtained vanadium concentrations in punat bay from 15 years ago (valković & bogdanović, 1996) . the vanadium means concentrations obtained in punat bay were between 0.01 and 0.256 mg/kg ww which were up to 10 times lower than the reported vanadium concentrations (2.7 to 3.2 mg/kg ww) for the persian gulf (fard et al., 2015). agah et al. (2009) reported that the vanadium concentration in fish in the persian gulf ranges between 0.16 and 0.71 mg/kg ww, which was approximately up to three times higher than those found in the present study. many authors (agah at al., 2009; abdolahpur monikh et al., 2011; fard et al, 2015) presented an increase of vanadium concentrations due to an increase of combustion of fossil fuel. when we compared vanadium mean concentrations for 1996 and 2020 in punat bay, a drop in concentrations is observed. also, table 5 shows 25 times higher mean vanadium concentrations measured in gilt-head breams caught in punat bay than in raša bay for the year 2020. the as mean concentration obtained in wild gilt-head breams (sparus aurata) caught in punat bay was 2.5 times higher than mean concentrations for 151 individuals of the same species of fish caught across the adriatic sea (sulimanec grgec et al., 2022). further, the as mean concentrations in wild punat fish was 72 times higher than in farmed samples. the obtained se mean concentration in punat gilt-head breams were similar with other obtained se concentrations in wild fish. (sulimanec grgec et al., 2022). 4. conclusion data analysis (nonparametric methods) conducted on sediment cores sulfur, phosphorous, iron, and a number of trace element concentrations confirms that the punat marina has had only a limited impact on the bay’s environment. mostly natural geochemical processes are reflected in the marine sediments’ geochemistry, at least considering the sites further away from marina’s port. several potentially toxic trace elements such as pb and cu, were found to be elevated in a sediment core located closest to the marina. of the regulated trace elements, only pb and cd, did not exceed recommended values in mussels and fish. it was obtained that wild gilt-head breams accumulated more hazardous trace elements such as v, pb, ba, as, cd, etc. than anglerfish. this paper shows interesting results that warrant further analytical work on the punat bottom sediments and biota for the purpose of environmental protection. 5. references abdolahpur monikh, f., hosseini, f., perry, s., maryamabadi, a., ghanemi, k., bastami, a.a. & karami, o. (2011): heavy metals levels in sediment and ray fish (dasyatis bennettii) from musa estuary, persian gulf.american-eurasian journal of toxicological sciences, 3/4, 224–227. agah, h., leermakers, m., elskens, m., fatemi, s.m. & baeyens, w. (2009): accumulation of trace metals in the muscle and liver tissues of five species from the persian gulf.– environmental monitoring assessment, 157, 499–514. doi: 10.1007/s10661-008-0551-8 bajc, z. & kirbiš, a. (2019): trace element concentrations in mussels (mytilus galloprovincialis) from the gulf of trieste, slovenia.– journal of food protection, 82/3, 429–434. doi: 10.4315/0362-028x.jfp-18-378 bogdanović, t., ujević, i., sedak, m., listeš, e., šimat, v., petričević, s. & poljak, v. (2014): as, cd, hg and pb in four edible shellfish species from breeding and harvesting areas along the eastern adriatic coast, croatia.– food chemistry, 146, 197–203. doi: 10.1016/j.foodchem.2013.09.045 brunović, d., miko, s., ilijanić, n., peh, z., hasan, o., kolar, t., šparica miko, m. & razum, i. (2019): holocene foraminiferal and geochemical records in the coastal karst dolines of cres island, croatia.– geologia croatica, 72/1, 19–42. doi: 10.4154/gc.2019.02 buskey, e.j., white, h.k. & esbaugh, a.j. (2016): impact of oil spills on marine life in the gulf of mexico: effect on plankton, nekton, and deep-sea benthos.– oceanography, 29, 174–181. doi: 10.5670/oceanog.2016.81 cardellicchio, n., buccolieri, a., di leo, a., giandomenico, s. & spada, l. (2008): levels of metals in reared mussels from taranto gulf (ionian sea, southern italy).– food chem., 107, 890–896. doi: 10.1016/j.foodchem.2007.09.011 cindrić, a.m., garnier, c., oursel, b., pižeta, i. & omanović, d. (2015): evidencing the natural and anthropogenic processes controlling trace metals dynamic in a highly stratified estuary: the krka river estuary (adriatic, croatia).– mar. pollut. bull., 94, 199–216. doi: 10.1016/j.marpolbul.2015.02.029 colina m., gardiner, p., rivas, z. & troncone, f. (2005): determination of vanadium species in sediment, mussel and fish muscle tissue samples by liquid chromatography-inductively coupled plasma-mass spectrometry.– anal. chim. acta, 538, 107–115. doi: 10.1016/j.aca.2005.02.044 cukrov, n., frančišković-bilinksi, s., hlača, b. & barišić, d. (2011): a recent history of metal accumulation in the sediments of rijeka harbour, adriatic sea, croatia.– mar. pollut. bull. 2011, 62, 154–167. ćosović, v., marjanac, t., drobne, k. & moro, a. (2008): outer dinarides: eastern adriatic coast. paleogene and neogene.– in: mccann, t. (ed.): the geology of central europe, volume 2: mesozoic and cenozoic. the geological society london, 1031–1139. european commission regulation (ec) no. 1881/2006 setting maximum levels for certain contaminants in foodstuffs. available online: http://extwprlegs1. fao.org/docs/pdf/eur68134original.pdf fard, n.j.h., ravanbaakhsh, m., ramezani, z., ahmadi, m., angali, k.a. & javid, a.z. (2015) determination of mercury and vanadium concentration in johnius belangerii (c) fish in musa estuary in persian gulf.– marine pollution bulletin, 97/1–2, 499–505. doi: 10.1016/j.marpolbul.2015.05.036 fiket, ž., mikac, n. & kniewald, g. (2017a): sedimentary records of the zrmanja river estuary, eastern adriatic coast—natural vs. anthropogenic impacts.– j. soils sediments, 17, 1905–1916. doi: 10.1007/s11368-016-1504-4 fiket, ž., mikac, n. & kniewlad, g. (2017b): mass fractions of forty-six major and trace elements, including rare earth elements, in sediment and soil reference materials used in environmental studies.– geostand. geoanalytical. res., 41, 123–135. doi: 10.1111/ggr.12129 fiket, ž., fiket, t., ivanić, m., mikac, n. & kniewald, g. (2019): pore water geochemistry and diagenesis of estuary sediments—an example of the zrmanja river estuary (adriatic coast, croatia).– j. soils sediments, 19, 2048–2060. doi: 10.1007/s11368-018-2179-9 fiket, ž., petrović, m., medunić, g., ivošević, t., fiket, t., zhang xu, l., wang, y. & ding, s. (2021): evaluation of the potential release tendency of metals and metalloids from the estuarine sediments: case study of raša bay.– molecules, 26, 6656. doi: 10.3390/molecules26216656 fox, m., mitchell, m., dean, m., elliott, c. & campbell, k. (2018): the seafood supply chain from a fraudulent perspective.– food security, 10, 939–963. doi: 10.1007/s12571-018-0826-z furdek turk, m., ivanić, m., dautović, j., bačić, n & mikac, n. (2020): simultaneous analysis of butyltins and total tin in sediments as a tool for the assessment of tributyl behaviour, long-term persistence and historical contamination in the coastal environment.– chemosphere, 127307. doi: 10.1016/j.chemosphere.2020.127307 gomes, t., pinheiro, j. p., cancio ,i., pereira, c.g., cardoso, c. & bebianno, m. (2011): effects of copper nanoparticles exposure in the mussel mytilus galloprovincialis.– environmental science and technology, 45/21, 9356–9362. doi: 10.1021/es200955s gulam, v., pollak, d. & podolszki, l. (2014): the analysis of the ¬ flysch badlands inventory in central istria, croatia.– geologia croatica, 67/1, 1–15. doi: 10.4154/gc.2014.01 hammer, ø., harper, d.a.t. & ryan, p.d. (2001): past: paleontological statistics software package for education and data analysis.– palaeontol. electron. 4, 1–9. available online: http://palaeo482 electronica.org/2001_1/past/issue1_01.htm (accessed on june 10, 2022). han, m., zhang, j., chu, w., chen, j. & zhou, g. (2019): research progress and prospects of marine oily wastewater treatment: a review.– water, 11/12, 2517. doi: 10.3390/w11122517 g eo lo gi a c ro at ic a geologia croatica 75/3420 jebreen, h., wohnlich, s., banning, a., wisotzky, f., niedermayr , a. & ghanem, m. (2018): recharge, geochemical processes and water quality in karst aquifers: central west bank, palestine.– environmental earth sciences, 77/6, 261. doi: 10.1007/s12665-018-7440-4 kang, s., ivošević, t., medunić, g. & dai, s. (2022): coal-derived sulphur and selenium in marine sediment cores (raša bay, croatia): recommended steps of analysing environmental earth data.– in: malvić, t. & ivšinović, j. (eds.): mathematical methods and terminology in geology. zagreb, rudarsko-geološko-naftni fakultet, 75–83. kljaković-gašpić, z., zvonarić, t., vrgoč, n., odžak, n. & barić, a. (2002): cadmium and lead in selected tissues of two commercially important fish samples from the adriatic sea.– water research, 36, 5023–5028. kljaković-gašpić, z., ozak, n., ujević, i., zvonarić, t. & barić, a. (2006): biomonitoring of trace elements (cu, cd, cr, hg, pb, zn) in eastern adriatic using the mediterranean blue mussels (2001-2005).– fresenius environ. bull., 15/9a, 1041–1048. kljaković-gašpić, z., ujevic, i., zvonaric, t. & baric, a. (2007): biomonitoirng of trace elements (cu, cd, cr, hg, pb, zn) in mali ston bay (eastern adriatic) using the mediterranean blue mussel (1998-2005).– acta adriat., 48/1, 73–88. lacerda, l.d., malm, o., guimaraes, j.r.d., salomons, w. & wilken, r.-d. (1995): mercury and the new gold rush in the south.– in: salomons, w. & stigliani, w.m. (eds.): biogeodynamics of pollutants in soil and sediments. risk assessment of delayed and non-linear responses. springer, berlin heidelberg new york, 213–245. maria, v.l. & bebianno, m.j. (2011): antioxidant and lipid peroxidation responses in mytilus galloprovincialis, exposed to mixtures of benzo(a)pyrene and copper.– comp. biochem. pharmacol. c, 154/1, 56–63. doi: 10.1016/j.cbpc.2011.02.004 marković, j., joksimović, d. & stanković, s. (2012) trace element concentrations in wild mussels from the coastal area of the southeastern adriatic, montenegro.– arch. biol. sci, belgrade, 64/1, 265–275. doi: 10.2298/abs1201265m medunić, g., kuharić, ž., fiket, ž., bajramović, m., singh, a.l., krivohlavek, a., kniewald, g. & dujmović, l. (2018): selenium and other potentially toxic elements in vegetables and tissues of three non-migratory birds exposed to soil, water, and aquatic sediment contaminated with seleniferous raša coal.– rudarsko-geološko-naftni zbornik, 33/3, 53–62. mihelčić, g., šurija, b., juračić, m., barišić, d. & branica, m. (1996): history of the accumulation of trace metals in sediments of the saline rogoznica lake (croatia).– science of the total environment, 182, 105–115. doi: 10.1016/0048-9697(95)05058-2 mikulić, n., oreščanin, v., legović, t. & zugaj, r. (2004). estimation of heavy metals (cu, zn and pb) input into punat bay.– environmental geology, 46, 62–70. doi: 10.1007/s00254-004-1015-2 miller, j.r., lechler, p.j. & desilets, m. (1998): the role of geomorphic processes in the transport and fate of mercury in the carson river basin, west-central nevada.– environmental geology, 33, 249–262. doi: 10.1007/s002540050244 mu, z., cheng, y., huang, q., hu, m., dong, w., fan, j. & wang, y. (2021): synchronous cycle of available phosphorus, iron, and sulfur in the sediment of lancang river reservoirs.– water, 13, 2691. doi: 10.3390/w13192691 nowrouzi, m., pourkhabbaz, a. & rezaei, m. (2012): bioaccumulation and distribution of metals in sediment sand avicenna marina tissues in the hara biosphere reserve, iran.– bull. environ. contam. toxicol., 89, 799–804. doi: 10.1007/ s00128-012-0751-3 oreščanin, v., mikulić, n., obhođaš, j., nađ, k. & valković, v. (2002): distribution of trace elements in the coastal sea sediments: punat bay in the northern adriatic.– journal of trace and microprobe techniques, 20/2, 247–260. doi: 10.1081/tma-120003727 oreščanin, v., barišić, d., lovrenčić, i., mikelić, l., rožmarićmačefat, m., pavlović, g. & lulić, s. (2005a): the influence of fly and bottom ash deposition on the quality of kaštela bay sediments.– environmental geology, 49, 53–64. doi: 10.1007/s00254-005-0058-3 oreščanin, v., lulić, s., medunić, g. & mikelić, l. (2005b): granulometric and chemical composition of the danube river sediments, batina village, croatia.– geologia croatica, 58/2, 185–194. parise, m., de waele, j. & gutierrez, f. (2009): current perspectives on the environmental impacts and hazards in karst.– environmental geology, 58, 235–237. doi: 10.1007/s00254-008-1608-2 parise, m., closson, d., gutierrez, f. & stevanović, z. (2015): anticipating and managing engineering problems in the complex karst environment.– environmental earth sciences 74, 7823. doi: 10.1007/s12665-015-4647-5 pavlović, g., barišić, d., lovrenčić, i., oreščanin, v. & prohić, e. (2005): use of fallout 137cs for documenting the chronology of overbank sediments from the river sava, croatia, and interpreting their geochemical patterns.– environmental geology, 47, 475–481. doi: 10.1007/s00254-004-1167-0 pavlović, g., prohić, e. & tibljaš, d. (2004): statistical assessment of geochemical pattern in overbank sediments of the river sava, croatia.– environmental geology, 46, 132–143. doi: 10.1007/s00254-004-1019-y perošević, a., joksimović, d., đurović, d., milašević, i., radomirović, m. & stanković, s. (2018): human exposure to trace elements via consumption of mussels mytilus galloprovincialis from boka kotorska bay, montenegro.– journal of trace elements in medicine and biology, 50, 554–559. doi: 10.1016/j. jtemb.2018.03.018 potts, p.j. (1992). a handbook of silicate rock analysis.– springer science + business media, new york, 631 p. doi: 10.1007/978-1-4615-3270-5 rađenović, a. & medunić, g. (2015): adsorptive removal of cr(vi) from aqueous solution by carbon black.– journal of chemical technology and metallurgy, 50/1, 81–88. reimann, c. & de caritat, p. (1998): chemical elements in the environment. factsheets for the geochemist and environmental scientist.– springer-verlag berlin heidelberg, germany, 398 p. reimann, c. & filzmoser, p. (2000): normal and lognormal data distribution in geochemistry: death of a myth. consequences for the statistical treatment of geochemical and environmental data.– environmental geology, 39, 1001–1014. doi: 10.1007/s002549900081 rosli, m., samat, s., yasir, m. & yusof, m. (2018): analysis of heavy metal accumulation in fish at terengganu coastal area, malaysia.– sains malaysiana, 47/6, 1277–1283. doi: 10.17576/jsm-2018-4706-24 şahin, v. & vardar, n. (2020): determination of wastewater behavior of large passenger ships based on their main parameters in the pre-design stage.– journal of marine science and engineering, 8, 8, 546. sulimanec grgec, a., jurasović, j., kljaković-gašpić, z., orct, t., rumora samarin, i., janči, t., sekovanić, a., grzunov letinić, j., matek sarić, m., benutić, a., capak, k. & piasek, m. (2022): potential risks and health benefits in the diet during the childbearing period: focus on trace elements and n-3 fatty acid content in commonly consumed fish species from the adriatic sea.– environmental advances, 8, 100226. doi: 10.1016/j.envadv.2022.100226 salomons, w. & foerstner, u. (1984): metals in the hydrocycle.– springer, berlin heidelberg new york, 349 p. doi: 10.1007/978-3-642-69325-0 sasmaz, m., obek, e. & sasmaz, a. (2019): bioaccumulation of cadmium and thallium in pb-zn tailing waste water by lemna minor and lemna gibba.– applied geochemistry, 100, 287–292. doi: 10.1016/j.apgeochem.2018.12.011 shu, y., wang, x., huang, z., song, l., fei, z., gan, l., xu, y. & yin, j. (2022): estimating spatiotemporal distribution of wastewater generated by ships in coastal areas.ocean & coastal management, 222, 106133. doi: 10.1016/j.ocecoaman.2022.106133 senesi, g.s., baldassarre, g., senesi, n. & radina, b. (1999): trace element inputs into soils by anthropogenic activities and implications for human health.– chemosphere. 39/2, 343–77. doi: 10.1016/s0045-6535(99)00115-0 stanković, s., tanaskovski, b., zlatić, b., arsenović, m. & pezo, l. (2014): analysis of trace elements in surface sediments, mussels, seagrass and seawater along the southeastern adriatic coast – a chemometric approach.– pure and applied chemistry, 86/7, 1111–1127. doi: 10.1515/pac-2014-0201 šušnjar, m., bukovac, j., nikler, l., crnolatac, i., milan, a., šikić, d., grimani, i., vulić, ž. & blašković, i. (1970): osnovna geološka karta sfrj 1:100 000, list crikvenica [basic geological map of sfry 1:10000, crikvenica sheet – in croatian].– institut za geološka istraživanja, zagreb, savezni geološki zavod, beograd. ternjej, i., gaurina srček, v., mihaljević, z. & kopjar, n. (2013): cytotoxic and genotoxic effects of water and sediment samples from gypsum mining area in channel catfish ovary (cco) cells.ecotoxicology and environmental safety 98, 119–127. doi: 10.1016/j.ecoenv.2013.09.014 valković, o. & bogdanović, i. (1996): pixe and xrf analysis of marine sediments.– nuclear instruments and methods in physics research b, 109/110, 488–492. doi: 10.1016/0168-583x(95)00956-6 vlahović, i., tišljar, j., velić, i. & matičec, d. (2005): evolution of the adriatic carbonate platform; paleogeography, main events, and depositional dynamics.– palaeogeography palaeoclimatology palaeoecology, 220, 333–360. vlahović, i., tišljar, j., velić, i. & matičec, d. (2007): immense tertiary carbonate jelar breccia, dinarides, croatia: a new view.– in: bush, d. (ed.): 2007 gsa denver annual meeting and exhibition: abstracts with programs, 146–146. wu, j., wang, l., wang, s., tian, r., xue, c., feng, w. & li, y. (2017): spatiotemporal variation of groundwater quality in an arid area experiencing long-term paper wastewater irrigation, northwest china.– environmental earth sciences 76, 460. doi: 10.1007/s12665-017-6787-2 2018 | 71/3 | 163 – 171 | 11 figs. | 1 tab. | www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 1. introduction both development and industrial activities have been proven to have a negative impact on and exacerbate natural disasters, climate change, environmental pollution, and therefore affect human health. subsurface contamination by petroleum hydrocarbons through underground storage tank leakage and spillage is one of the most challenging geo-environmental issues faced by many countries and results in the reduced quality of groundwater. more complex problems emerge when the surface or subsurface has experienced earthquake vibration, which could promote the migration of petroleum hydrocarbons into groundwater resources. petroleum hydrocarbons, also known as non-aqueous phase liquids (napls), are organic solvents such as toluene, benzene, hexane and naphthalene that usually arise from industrial activities, that do not mix with water (tian et al., 2014). napl may be divided into two categories, dense non-aqueous phase liquids (dnapl), which are more dense than water, and light non-aqueous phase liquids (lnapl), which are less dense than water. the lnapl migrate through the unsaturated soil and float on the groundwater surface, while the dnapl may penetrate into the underlying groundwater. fuels released such as gasoline, diesel, lubricants, jet fuel, collectively referred to as lnapls, are of concern due to the hazards caused to human-health and the environment when in contact with lnapls (tomlinson et al., 2017). earthquake vibration causing cracked soil, deformation of soil structure, and unstable soil structure may exacerbate vibration effect influence upon non-aqueous phase liquid migration in double-porosity soil norhan abd rahman1 , loke kok foong2, ramli nazir1 and roland w lewis3 1 universiti teknologi malaysia, faculty of civil engineering, centre of tropical geoengineering, johor, malaysia (norhan@utm.my) 2 universiti teknologi malaysia, faculty of civil engineering, johor, malaysia 3 university of wales swansea, school of engineering, swansea, w. glam, sa2 8pp, united kingdom doi: 10.4154/gc.2018.14 abstract natural disasters such as earthquakes, el-nino, tsunamis and water pollution have a negative impact on human health and living environment. some of these may give rise to subsurface vibrations that can potentially increase groundwater pollution risks in double-porosity systems. the more complicated situation was where underground storage tanks and petroleum pipeline damage have caused the leakage of non-aqueous phase liquids (napls) which migrated into the groundwater resources. these problems need to be addressed by both professionals and researchers worldwide to ensure the sustainability of groundwater utilization. this paper aims to investigate and understand napl migration in vibrated double-porosity soils. to do so it was necessary to study the phenomena and characteristic of soil structure and the pattern of napl migration to identify cost-effective remediation schemes. a laboratory experiment was conducted to study the phenomena and characteristics of vibration response and napl migration in double-porosity soil deformation under vibration effect using a digital image processing technique (dipt). the outcomes of the experiment show that the gradual increase of vibration table excitation frequency yielded different vibration responses from the respective soils. this indicated that soil surface acceleration depended significantly on the soil conditions, soil water content, soil structure and the pattern of soil fracturing. napl migration was faster in sample 2 with 150ml toluene than sample 1 with 70ml toluene and this could be because the greater amount of toluene in sample 2 exerted an extra entry force on top of the soil sample that had yet to migrate through the sample surface. finally, it was concluded that the dipt may provide detailed information, and can be used to understand and identify the remediation method as well as to ensure the sustainable consumption of groundwater. napl pollution (loke et al., 2017). according to tomlinson et al. (2017), liquid migration, in reference to lnapl behaviour and movement in the subsurface, is complicated. the speed and phenomena of the petroleum hydrocarbon liquid migration into the subsurface system may be more intricate under the influence of vibrated porous soil. therefore, a better understanding of napl migration in vibrated porous soil was necessary in order to study the phenomena and characteristics of soil structure. the pattern of napl migration is important to identify remediation schemes and to ensure the sustainability of groundwater resources and the geo-environment. porous media such as deformable double-porosity soil has been classified as soils with interaggregate pores and intra-aggregate pores that display a bimodal pore-size distribution pattern and are normally found in agricultural topsoils and compacted soils (li & zhang, 2009; elzein et al., 2006). a more comprehensive understanding with respect to napl migration under the phenomena of fractured double-porosity soil is still required. this study proposed a new model concept with soil porosity that includes features from the three continuums of fracture porosity, primary porosity, and secondary porosity (based on a literature review). the fracture porosity continuum developed through the affect of vibration had caused the double-porosity soils to fracture. meanwhile, the primary porosity and secondary porosity continuums concept represents double porosity soils that consist of inter-aggregate and intra-aggregate pore matrix blocks, respectively, with different hydraulic properties embedded in a network of interconnected article history: manuscript received january 06, 2018 revised manuscript accepted june 10, 2018 available online october 12, 2018 keywords: vibration, laboratory experiment, napls migration, aggregate kaolin, image analysis method g eo lo gi a c ro at ic a geologia croatica 71/3164 fractures (loke et al., 2017). the most critical contaminants include petroleum hydrocarbons such as toluene, (lnapl), which have been selected as the liquids used in this study. the soil structure affects the flow rate and characteristics of liquid migration. in common conditions, soil that displays two specific scales of porosity media is termed a double-porosity soil (carminati et al., 2008). geo-materials habitually display two scales of porosity, which are macro pores and micro pores (manrique et al., 2007). according to sa’ari et al. (2015), doubleporosity soils have different hydraulic properties of two sub-region media due to the differing pore size characteristics. similarly, barbara et al. (2016) & fredlund et al. (2010) found that fractured porous media significantly change the mechanical properties and hydrological characteristics. existing research recognizes the critical role played by cracked soil where it can significantly influence the water f low through the fractured soil structure (krisnanto et al., 2014). according to lakeland et al. (2014), fractured double-porosity soil is formed due to earthquakes or other vibration effect in which loosely packed water-saturated granular soils (sand and silt) are subjected to great shaking, where they may liquefy and cause large deformation of the soil structure with strong destructive power. in earthquake engineering theory, the bedrock motion with the highest response is the peak ground acceleration (pga) and the free surface motion with highest response is the peak surface acceleration (psa). these accelerations can be either amplify or disamplify, based on eurocode 8 (2004) part 1 for classifying five ground types (a to e), where it helps to characterizing the soil type (loke et al., 2016). therefore, this study used ground response analysis to identify the soil sample by the propagation of ground motion to the surface because in practice, ground response analysis was used to determine the crack and ground type. lewandowska et al. (2005) stated that soil in the laboratory can be used to create double-porosity for one-dimensional infiltration experiments, which is how most studies concerning double-porosity soil are carried out. furthermore, laboratory prepared double-porosity kaolin soil was used for one-dimensional drying and consolidation experiments as performed by bagherieh et al. (2009). double-porosity media have been studied in the past few decades by a number of researchers. for example, (alazaiza et al., 2017; ngien et al., 2016; sa’ari et al., 2015; tranngoc et al., 2014; ryzhik, 2007; pao & lewis, 2002) used numerical methods and experimental methods on doubleporosity soil media and have thereby contributed to an understanding of the soil characteristics. however, the studies were limited to intact double-porosity soils without applying any vibration effect on these soils. in this research, a digital image analysis method was used to study the migration of lnapl in a fractured double-porosity soil represented by an s300 kaolin soil. a digital image analysis method was used to understand and analyse the pattern of lnapl migration in a fractured double-porosity soil. an overview by agaoglu et al. (2015) found that the laboratory work involved non-destructive and non-intrusive imaging techniques which used characterization and observation of multiphase flow system for greater accuracy. therefore, a number of researchers (janina et al., 2017; sitthiphat & siam et al., 2016; peng et al., 2015; sa’ari et al, 2015; kamaruddin et al., 2011; ngein et al., 2011; flores et al., 2011; oostrom et al., 2007) have carried out various techniques and methods of non-destructive image analysis for liquid migration experiments. as stated by maas & hampel (2006), an image analysis technique in the field of civil engineering was normally used to study the object flow absorption movement in boundary layers and liquid migration of small properties specific to the propagation of structure crack extension, and for this argument, a digital image processing technique was acceptable for use in the study of lnapl migration in a fractured double-porosity soil. in addition, ngien et al. (2012) asserted that the problems inherent in gathering data concerning hydrocarbon liquid movement characteristics and the laboratory experiments will go a long way in the effort to comprehensively understand, monitor, observe and solve groundwater contaminant problems. to the best of our knowledge and upon reviewing other research papers, experiments on lnapl migration in fractured double-porosity soil under vibration effect represent a knowledge gap to be investigated and evaluated. therefore, a laboratory experiment was conducted to study the phenomena and characteristics of lnapl migration in double-porosity soil deformation under vibration effects. thus, to achieve the purpose of this study, the identified objectives were (i) to investigate the vibration responses with different vibration frequency for the double-porosity soil, (ii) to determine the characteristics of lnapl migration in vibrated double-porosity using image analysis, (iii) to distinguish processes controlling lnapl migration with different quantities of toluene in fractured double-porosity soil. 2. materials and methods the laboratory soil sample preparation, laboratory experiment and image processing setup used in this study are outlined below. 2.1. laboratory soil sample preparation the soil sample material utilized for this study to create doubleporosity was commercially available kaolin soil produced by kaolin malaysia sdn bhd. the kaolin soil properties were tested based on british standard bs 1377-2:1990 and bs 1377-5:1990 to obtain liquid limit =41.5%, plastic limit = 27.5%, plasticity index = 14%, particle density = 2.66 mg/m3, particle size distribution = (4% sand; 91% silt; 5% clay) and falling head permeability test (k average) = 5.41 x 10-9 m/s. the kaolin soil was classified under the unified soil classification system as silt with low plasticity (ml) based on the value of atterberg limits and particle size distribution. based on hillel (1998), the total porosity for a double-porosity soil is defined as the sum of the inter-aggregate and intra-aggregate porosities. this is given by eq. (1) as int intj j j= +t er ra (1) wherejt is the total porosity, intj er is the inter-aggregate porosity, and intj ra is the intra-aggregate porosity. the approach used in this study for estimating the inter-aggregate porosity and intraaggregate porosity of the aggregated soil is to adopt the intraaggregate porosity as the volumetric moisture content at field capacity (david & trumbore, 1995). the soil science society of america (1987) has identified the field capacity as the moisture content remaining in a soil for two or three days after wetting with water, which becomes negligible after free drainage. in this experiment, it was further observed that no free drainage of the cured soil occurred after curing for the field capacity. therefore, this theory brings us to eq. (2). intj j j= -er t w (2) where jw is the volumetric water content. the total porosity and volumetric water content can be calculated in turn using eqs. (3) to (4), respectively (ghezzehei & or, 2003). j = =v t s t t t v v v v v (3) g eologia c roatica abd rahman et al.: vibration effect influence upon non-aqueous phase liquid migration in double-porosity soil 165 j = w w t v v (4) where vv is the volume of voids, tv is the overall volume of the sample, sv is the volume of solids only, and wv is the volume of water. the overall volume of the sample is the volume after compression and can be calculated through eq. (5). (ghezzehei and or 2003) 2 4 p =tv h d (5) where h is the soil sample height, and d is the soil sample diameter. the volume of solids can be calculated using eq. (6). (ghezzehei and or 2003) r = s s s m v (6) where sm the mass of solids is equal to tm divided by (1 + water content), tm is the total mass and rs is the particle density. the volume of water can be calculated by dividing the mass of water by the density of water as in eq. (7). (ghezzehei and or 2003). r = w w w m v (7) therefore, the double-porosity value for this study can be calculated by using eqs. (1) to (7) with the parameter values such as h = 0.1 m, d = 0.094 m, rs = 2.66 mg/m3, tm (sample 1) = 1.012 kg, moisture content sample = 30%. by using these values as mentioned, the inter-aggregate porosity and intra-aggregate porosity for sample was calculated as 0.24 and 0.34, respectively. it is evident that the 30% moisture content used in this study falls within the range established from the available literature, as the moisture content at field capacity ranged from 0.226 to 0.40 (food and agriculture organization 2005; international atomic energy agency 2008). thus, the total porosity was 0.24 + 0.34 =0.58. the method used to prepare the aggregated kaolin soil sample has been based on the established method by bagherieh et al. (2009). the preparation of the kaolin soil sample used 30% water content, which was based on the value of the liquid limit, and optimum moisture content for kaolin soil was 28%. thus, the dried kaolin powder was mixed with 30% water content and constant pouring of distilled water was applied to control the water content within the mixture. the mixture was kept in cool conditions for a minimum of 24 hours to equalise the mixture which was placed in a plastic bag for the purpose of maintaining the soil moisture content. then the mixture was broken by hand and passed through a 2.36mm sieve to obtain kaolin granules to create the double-porosity soil structure. a pre-determined amount of kaolin granules with a weight of 0.93kgwas placed in a circular acrylic soil column and compressed to a height of 100mm using a compression machine at a compression rate of 1kgf/cm2. the 100mm height of soil sample was chosen to ensure uniformity throughout the sample depth. the prepared aggregated soil sample is shown in (fig. 1). the circular acrylic soil column with a sealed base with dimensions of 300 mm high x 100 mm-outer diameter and 94 mminner diameter was used throughout the experiment. the circular acrylic soil column was specially designed to be used on a vibration table and for the observation of the phenomena occurring throughout the whole acrylic soil column. the acrylic soil column with a triangular base plate was securely fixed and bolted on the vibration table in order to prevent any movement and bouncing of the soil column during the vibration process. the experimental setup and the acrylic circular soil column showed similar effects when using either an economical vibration table, or a shake table. to ensure that the vibration table functioned well and could produce the same reliable data as the shake table, the vibration table frequencies must be calibrated using a high sensitivity accelerometer together with a dewesoft sirius system data-logger to check and obtain the excitation frequency for the vibration table. the vibration table with a built in frequency control panel was vibrated in the vertical direction. barry et al. (2008) reported that major earthquakes have an upper frequency of 20hz. however, this can be much lower depending on the seismic activity. a moderate to low seismic earthquake such as the one that struck ranau, malaysia is one such example. this 6.0 magnitude earthquake had a peak ground acceleration of 0.12g (harith et al., 2017). thus, based on the details, seismic activity and seismosignal software analysis display an approximate vibration frequency of only 0.95hz. following this, vibration frequency in the range of 0.29hz to 0.98hz was adopted in this study. the coupling system between the accelerometer and soil used soft plasticine with a strong bonding characteristic. meanwhile, another accelerometer was attached to the vibration table near to the soil sample with the same procedure. the vibration table setup used to vibrate the aggregated soil sample was developed by loke et al. (2017) as shown in (fig. 2). figure 1. the prepared kaolin soil figure 2. 3d diagram of vibration table setup (loke et al., 2017) g eo lo gi a c ro at ic a geologia croatica 71/3166 the result of the fractured soil pattern with 30% moisture content for samples 1 and 2 after the vibration process are shown in (fig. 3). the theory of fractured double-porosity was to prove that the vibration effect had caused the double-porosity soil to fracture. the fracturing on the top of soil can be clearly seen. 2.2. laboratory experiment and image processing setup procedure the circular acrylic soil column containing fractured doubleporosity soil was used to observe and monitor the lnapl migration that occurs inside the whole circular column area with the aim of simulating groundwater contamination and non-intrusion of the original soil sample setup. in each sample, the experimental measurement and setup of the v shape mirror and soil column position was arranged as shown in (fig. 4) for lnapl migration image acquisition. a nikon d90 dslr digital camera was used for lnapl migration image acquisition at specific time intervals. the camera comes equipped with a sensor size of 23.6mm x 15.8mm and used a medium size image format of 3216 x 2136 pixels resulting in each pixel having a size resolution of 5.6µm x 5.6µm. during the process of image capture, a remote control was used to prevent movement and shaking of the camera. to soften the problem of insufficient image acquisition, this experiment used a single digital camera, and two mirrors for reflection positioned behind the circular soil column were adjusted to enable a clear image facing the digital camera. in addition, on the spot images of the lnapl migration throughout the whole area of the soil column circumference can be captured by just a single click of the digital camera. the experiment light source came from a light output of 2600 lumens/watt that was secured above the soil column. a white paper with pre-drawn gridline (20mmx20mm) was first sheathed onto the soil column and used as a control point on the reference image. the experiment started by instantaneously pouring the lnapl into the top centre of the fractured soil sample in the circular acrylic soil column. sample 1 used 70ml of toluene, while 150ml of toluene was used in soil sample 2. the toluene for both experiments was dyed red using oil-red-o powder to enhance the visibility during the migration process. after the toluene had covered the whole surface area of the fractured soil sample, the first digital image of toluene migration was captured. in both experiments, subsequent digital images were taken at specific time intervals to capture the lnapl migration. a total of 76 images were subsequently recorded over 5 minutes for soil sample 1, while 19 images were captured in 57 seconds for soil sample 2. the digital images captured for both experiments were saved in jpeg format as shown in (fig. 5) and transferred to computer for image processing analysis using matlab and surfer software. the matlab routines were used to perform the following task; to extract an area of interest from the captured image and to transform the area of interest from the distorted image to a scale image via the affine transformation method; to convert the jpeg scale images to red green blue (rgb) and hue saturation intensity (hsi) images; to extract hsi digital value from hsi image and save the hsi value in a text file format. then, surfer software was used to digitize the control point from the reference image and to generate a map or plot the migration pattern of lnapl in porous media using the hsi value. a reference image was digitized with the area of interest, which refers to a pre-determined migration boundary area (front image and v shape reflection image) for the experiment that contained the lnapl. finally, the contour plot pattern was plotted for the lnapl migration in fractured porous media based on the generated hsi value from image processing analysis. the hsi contour plot of lnapl migration behaviour can provide detailed information to facilitate researchers to understand the pattern of lnapl migration characteristic and the migration flow. figure 3. a) sample 1 after vibration process with fracture. b) sample 2 after vibration process with fracture. 600mm 80mm acrylic circular soil column (100mm diameter) v shape reflection mirror (700mm x 600mm) nikon d90 digital camera figure 4. digital image acquisition experiment setup and measurement position g eologia c roatica abd rahman et al.: vibration effect influence upon non-aqueous phase liquid migration in double-porosity soil 167 3. results the results of the surface acceleration and vibration table acceleration for samples 1 and 2 with 30% moisture content are shown in (fig. 6). each frequency range has a different response, however only the peak acceleration has been chosen for discussion. referring to (fig. 6), the acceleration response result shows the highest peak soil surface acceleration value at 1.52g and the lowest peak soil surface acceleration value at 0.44g, with the highest soil surface acceleration response observed to be at the middle of the vibration table excitation frequency range. the pattern and relationship could be seen to increase in relation to table acceleration. therefore, it has been observed that figure 5. digital image in jpeg format the gradual increase of vibration table excitation frequency yielded different responses from the respective soils. furthermore, during the observations of samples 1 and 2, the aggregated kaolin soil started to fracture at a frequency of 0.39hz and when the peak surface acceleration was about 0.91g. the fractured soil sample displayed dis-amplification shaking because the soil was still in the stiff condition. therefore, based on eurocode 8 (2004) part 1 for classification of ground type, samples 1 and 2 have ground type b, which has a very stiff soil, because soil samples 1 and 2 with 30% moisture content have dis-amplification shaking during the vibration process. the results of the lnapl migration process for the top soil surface with the divided measurement of actual size column circumference zone for samples 1 and 2 are shown in (fig. 7). the downward migration pattern of the hsi contour plot of dyed lnapl with 70 ml and 150 ml in the fractured double-porosity soil sample with 30% moisture content for samples 1 and 2, respectively, are shown in (fig. 8). in both samples, given the method of introduction of the solution to the soil surface, the flow of the lnapl would have migrated into the kaolin soil sample before the whole soil sample surface was covered. the test samples exhibited a distinctive aggregation of kaolin granules after the vibration effect and the width of the fractured soil surface in the vibrated sample was measured by using a crack width microscope model 58-c0218. the results of the fractured soil surface for samples 1 and 2 were 0.8mm and 1.3mm, respectively. in sample 1, the selected hsi plots of dyed lnapl migration at intervals of 5, 120, 240, and 300 seconds, respectively, are shown in (fig. 8a). according to the hsi intensity contour plot figure 7. a) sample 1 (70 ml lnapl). b) sample 2 (150 ml lnapl) migrated soil surface with measurement of actual column circumference zone. figure 6. a) surface acceleration response b) vibration table acceleration response for sample 1 and 2 with 30% moisture content. g eo lo gi a c ro at ic a geologia croatica 71/3168 result, the flow of the dyed toluene migration was not consistently downward toward the front x-axis horizontal line as the fractured double-porosity soil was non-homogenous. rapid migration occurred at the cracked soil surface compared to uncracked areas of the soil surface as shown in (fig. 7a). for the dyed lnapl to completely recede from view over the whole soil surface area of the test took about 4 seconds, which is very rapid. meanwhile, the overall duration for dyed lnapl migration from the top surface to the bottom was 300 seconds and further observation at 600 seconds showed no changes in migration pattern where the lnapl migration reached 100% downward depth of the soil column. at 5 seconds after the commencement of the experiment, the dyed lnapl migration reached three quarters of the test sample depth at the location of the fractured soil surface (fig. 8a).the lnapl (70ml) could migrate to the bottom in 300 seconds. this is because the capillary force that was exerted by a small quantity of the lnapl was not sufficient enough to help migration rate. in sample 2, the intervals of 5, 24, 36 and 57 seconds, respectively, were selected for dyed lnapl migration hsi contour plot figure 8. a) sample 1 (70ml lnapl). b) sample 2 (150ml lnapl) hsi plots of downward migration in fracture double-porosity soil (fig. 8b). the lnapl migration was similar to the results found in sample 1. the flow of dyed lnapl migration was not uniformly downward at the front boundary horizontal line due to the inhomogeneity of the fractured double-porosity soil structure. at 5 seconds after the initiation of the experiment, the dyed lnapl migration reached three quarters (3/4) of the test sample at the location of fractured soil surface (fig. 7b). it took about 24 seconds for the dyed lnapl to completely disappear from the top soil surface area into the fractured soil sample of the test. meanwhile, the overall duration for the dyed lnapl migration from the top surface to the bottom was 57 seconds and further observation at 300 seconds showed no changes in migration pattern where the lnapl migration fully reached 100% depth of the soil column. from the results, it can be seen that soil sample 2 had the faster migration as a shorter time was taken for the lnapl to reach the bottom of the soil column. soil sample 2, with the fractured width of 1.3mm, had a greater entry pressure compared to sample 1 with a 0.8mm wide fracture because the fracture width g eologia c roatica abd rahman et al.: vibration effect influence upon non-aqueous phase liquid migration in double-porosity soil 169 two samples, sample 1 migrated faster compared to sample 2 due to greater entry pressure. sample 2 entry pressure was lower due to greater lnapl thickness and the larger quantity of the lnapl. furthermore, migration behaviour and migration rate differed between samples 1 and 2 with a shorter migration time for sample 2 because of the capillary force exerted by the dyed lnapl pressure in the top surface of the soil sample that had yet to migrate into the soil sample. this is seen by the darker saturation colour in the 5 second hsi plot in sample 2 compared to sample 1. in addition, air bubbles were continuously observed at the soil surface of lnapl to be reducing due to the wettability of controlled the entry for the liquid migration into the fractured double-porosity soil. the driving force with which a lnapl release could migrate into the unsaturated fractured double-porosity soil is determined principally by the lnapl thickness (the height of the lnapl release above the soil surface) because the lnapl release was initially greater. however, the lnapl thickness could reduce and dissipate with time finally leading to the migration of lnapl into the fractured double-porosity soil. the lnapl thickness for samples 1 and 2 are shown in (fig. 9) and are 10mm and 23mm, respectively. dissipation times of the liquids were 4 seconds and 24 seconds, respectively for the two samples for total migration from the soil surface into the soil. of the figure 9. the lnapl thickness for sample 1 and 2 figure 11. measured values of lnapl migration depth as a function of column circumference for selected critical time interval in sample 2. figure 10. measured values of lnapl migration depth as a function of column circumference for selected critical time interval in sample 1. g eo lo gi a c ro at ic a geologia croatica 71/3170 the liquid in the soil sample. referring to (fig. 8), the consistency of the colour showed primary porosity to be present in that particular area and the lnapl migration occurred through the primary porosity in addition to both secondary porosity and fractured porosity. this study also used the partially unsaturated fractured double-porosity soil and the permeability test for kaolin soil proved kaolin has permeability characteristic, thus it could be expected that primary porosity could transport the lnapl, not just the secondary and fractured porosity. the measured values of dyed lnapl migration depth as a function of column circumference for selected critical time intervals are shown in (figs. 10 and 11) for samples 1 and 2, respectively. referring to (fig. 10), the dyed lnapl migrated fastest between 240 to 300 mm and 160 to 180 mm along the soil column circumference because of the cracked soil surface condition compared to other locations on the soil surface that were not cracked as shown in (fig. 7a). the dyed lnapl migration was dramatically expedited between 5 seconds and 120 seconds, which shows the extraordinary difference in migration patterns. this could be because the factor of dyed lnapl pressure was high at initial condition of the fractured double-porosity soil, causing the lnapl to easily penetrate downward into the cracked soil sample. based on (fig. 11), the dyed lnapl migration was fastest between 50 to 90 mm and 110 to 140 mm along the soil column circumference. the measured actual column circumference zone as shown in (fig. 7b) indicated the location of the surface crack. the dyed lnapl migration was expedited between 5 12 seconds, which indicates significant changes in the migration pattern. this phenomena was similar to sample 1, where the influential factors were the capillary force exerted by the dyed lnapl and high flow water pressure at the condition where the soil samples were fractured and cracked. besides, soil sample 2 with the sufficient lnapl head and lnapl thickness exceeded pore entry pressure and caused the migration time to be faster compared to soil sample 1. therefore, the aforementioned factor caused the dyed lnapl migration to penetrate downward into the soil sample easier and faster. the calculated higher migration flow rate and overall average speed for every 50 mm column circumference zone is presented in table 1. sample 1 shows the higher migration flow rate from initial to 5 seconds was at the 250 mm column circumference zone with the migration flow rate of 61.403 mm/s. meanwhile, the other high migration flow rates occurred at 200 mm and 150 mm column circumference with the value of 18.837 mm/s and 12.397 mm/s, respectively. thus, the overall average dyed toluene migration flow rate for sample 1 is 4.389 mm/s. the highest average migration flow rate was at the 250 mm column circumference zone at 9.145 mm/s. this could be because the larger fractured and cracked soil structure after the vibration was at the 250mm position. sample 2 displays the higher migration flow rate from initial to 5 seconds at 50 mm column circumference zone with the migration flow rate of 76.778 mm/s. meanwhile, the column circumference zone at 100 mm and 0 mm also has a high migration speed rate with the values of 20.551 mm/s and 16.917 mm/s, respectively. the higher migration speed rate was due to the cracked or fractured soil sample surface (fig. 7b) for the actual column circumference. therefore, the overall average dyed toluene migration flow rate for sample 2 is 5.503 mm/s. this scenario occurred because the higher quantity of 23mm thickness of lnapl (head) in sample 2 caused the greatest pressure on top of the soil surface, forcing penetration to be faster than soil sample 1 with only 10mm lnapl thickness. the faster migration was caused by the greater entry pressure exerted by the lnapl force on top of the fractured soil sample. 4. conclusions the laboratory experiment on lnapl migration was carried out on fractured double-porosity soil with 30% moisture content. this purpose of the experiment was to investigate the vibration of soil sample and lnapl behaviour as well as to differentiate the characteristics and flow rate in the fractured double-porosity soil in a circular soil column. the digital image processing technique using a self-development matlab routine and surfer software was applied to analyse the apl and napl migration data obtained from captured digital images. from the results observed, both samples have been classified as ground type b, in which the soil has a very stiff soil structure and dis-amplification shaking during the vibration process. in sample 2 (57 seconds) lnapl migrated faster from top to the bottom of soil column compared to sample 1 (300 seconds). samples 1 and 2 both fully migrated to the bottom of the soil column. furthermore, sample 2 average flow rate of 5.503 mm/s was higher compared to the sample 1 flow rate of 4.389 mm/s. the lnapl migration into the subsurface systems was allowed when the lnapl head (thickness) drives the entry, as the non-wetting lnapl capillary pressure overcomes the entry pressure. a similar experiment on napl migration in intact double-porosity soil by sa’ari et al. (2015) found that the migration of napl from top to bottom take 2280 seconds. however, in our study similar migration condition for both sample took only 57 and 300 seconds, respectively, to reach bottom of soil column with the condition of fractured double-porosity soil. this shows the ease of liquid entry into the fractured double-porosity soil compared to intact double-porosity soil. the results proved that the factors that significantly influenced table 1. migration flow rate for every 50mm column circumference. column circumference zone (mm) migration flow rate (mm/s) soil sample 1 (70ml lnapl) soil sample 2 (150ml lnapl) higher flow between initial to 5 seconds average flow for all the time interval higher flow between initial to 5 seconds average flow for all the time interval 0 0.837 2.833 16.917 4.669 50 0.598 2.522 76.778 12.927 100 0.597 2.703 20.551 5.343 150 12.397 4.579 11.834 3.656 200 18.837 5.586 14.797 3.894 250 61.403 9.145 14.238 3.814 300 11.946 3.353 15.900 4.218 g eologia c roatica abd rahman et al.: vibration effect influence upon non-aqueous phase liquid migration in double-porosity soil 171 the lnapl migration in soil samples 1 and 2 were the lnapl head (thickness), soil sample fracture pattern, soil sample porosity, soil sample structure, liquid wettability in the soil sample and liquid capillary pressure. in conclusion, this study indicates that the soil sample acceleration response and lnapl migration contour plots and the migration flow rate have provided preliminary information to researchers and professionals to comprehensively understand the pattern of lnapl migration behaviour that could be used to identify the remediation method and to ensure sustainable consumption of groundwater. acknowledgements this study was supported by the research management centre (rmc), universiti teknologi malaysia under research university grant – tier 1 (py/2016/06547) from the ministry of higher education malaysia. the authors would also like to thank their respective university, public service department malaysia, geotechnical laboratory, hydraulic and hydrology laboratory, engineering seismology and earthquake engineering research group (eseer), and survey unit, faculty of civil engineering, universiti teknologi malaysia for kind assistance lent to this research. the second author was supported through the federal training award by the public service department under prime minister’s department, malaysia. references agaoglu, b., copty, n.k., scheytt, t. & hinkelmann, r. (2015): interphase mass transfer between fluids in subsurface formations: a review. – advances in. water resources, 79, 162–194. doi:10.1016/j.advwatres.2015.02.009 alazaiza, m.y.d., ngien, s.k., bob, m.m., kamaruddin, s.a. & ishak, w.m.f. (2017): influence of macro-pores on dnapl migration in double-poro sity soil using light transmission visualization method. – transport in porous media, 117, 103–123. doi:10.1007/s11242-017-0822-3 bagherieh, a.r., khalili, n., habibagahi, g. & ghahramani, a. (2009): drying response and effective stress in a double porosity aggregated soil. – engineering geology, 105/1–2, 44–50. doi:10.1016/j.enggeo.2008.12.009 barbara, s., felix, s., tivadar, m.t., & gabor, s. (2016): palaeofluid evolution in a fractured basalt hosted reservior in the ulles-ruzsa-bordany area, southern sector of the pannonian basin.– geologia croatica, 69/3, 281–293. doi:10.4154/ gc.2016.25 carminati, a., kaestner, a., lehman, p. & flühler, h. (2008): unsaturated water flow across soil aggregate contacts.– advances in water resources, 31/9, 1221–1232. doi: 10.1016/j.advwatres.2008.01.008 davidson, e.a. & trumbore, s.e. (1995): gas diffusivity and production of co2 in deep soils of the eastern amazon.– tellus, 47, 550–565. doi: 10.3402/tellusb. v47i5.16071 el-zein, a., carter, j.p. & airey, d.w. (2006): three-dimensional finite elements for the analysis of soil contamination using a multiple-porosity approach.– international journal for numerical and analytical methods in geomechanics, 30/7, 577–597. doi:10.1002/nag.491 flores, g., katsumi, t., inui, t. & kamon, m. (2011): a simplified image analysis method to study lnapls migration in porous media.– soil and foundation, 51, 835–847. doi: 10.3208/sandf.51.835 food and agriculture organization (2005): drought-resistant soilsoptimization of soil moisture for sustainable plant production, fao land and water bulletin 11.– food and agriculture organization of the united nations, rome fredlund, d.g., houston, s.l., nguyen, q. & fredlund, m.d. (2010): moisture movement through cracked clay soil profiles. – geotechnical and geological engineering, 28/6, 865–888. doi:10.1007/s10706-010-9349-x ghezzehei, t.a., & or, d. (2003): pore-space dynamic in a soil aggregate bed under a static external load.– soil science society america journal, 67, 12–19. doi: 10.2136/sssaj2003.1200 harith, n.s.h., adnan, a.r., shoushtari, a.s. (2017): deaggregation of probabilistic ground motions in the kota kinabalu and lahad datu towns of sabah, malaysia.– in matec web of conferences, seoul, south korea, pp.09001, 2-11. doi:10.1051/matecconf/201713809001 hillel, d. (1998): environmental soil physics. academic press, san diego. international atomic energy agency (2008): field eztimation of soil water content – a practical guide to methods, instrumentation and sensor technology, iaea-tcs-30.– international atomic energy agency, vienna. janina, h., szabolcs, b., & janos, g. (2017): cluster defined sedimentary elements of deep-water clastic depositional systems and their 3d spatial visualization using parametrization: a case study from the pannonian-basin.– geologia croatica, 70/2, 73–78. doi:10.4154/gc.2017.06 kamaruddin, s.a., sulaiman, w.n.a., rahman, n.a., zakaria, m.p., mustaffar, m. & sa’ari, r. (2011): two-dimensional laboratory investigation of light non-aqueous phase liquid migration in subsurface environment. – in: contemporary environment quality management in malaysia and selected countries, serdang, malaysia: universiti putra malaysia press. krisnanto, s., rahardjo, h., fredlund, d.g. & leong, e.c. (2014): mapping of cracked soils and lateral water flow characteristics through a network of cracks. – engineering geology, 172, 12–25. doi:10.1016/j.enggeo.2014.01.002 lakeland, d.l., rechenmacher, a. & ghanem, r. (2014): towards a complete model of soil liquefaction: the importance of fluid flow and grain motion.– in: proceedings of the royal society a – mathematical, physical and engineering sciences, london a470:20130453. doi:10.1098/rspa.2013.0453 lewandowska, j., szymkiewicz, a., gorczewska, w. & vauclin, m. (2005): infiltration in a double-porosity medium: experiments and comparison with a theoretical model.– water resources research, 41/2, w02022. doi:10.1029/2004wr003504 li, x. & zhang, l.m. (2009): characterization of dual-structure pore-size distribution of soil. – canadian geotechnical journal, 46, 129–141. doi: 10.1139/t08-110 loke, k.f., rahman, n.a. & nazir, r. (2017): experimental study on unsaturated double-porosity soil phenomena under vibration effect.– jurnal teknologi, 79/4, 65–72. doi:10.11113/jt.v79.9976 loke, k.f., rahman, n.a. & ramli, m.z. (2016): a laboratory study of vibration effect for deformable double-porosity soil with different moisture content.– malaysian journal of civil engineering, 28, si/3, 207–222. maas, h.g. & hampel, u. (2006): photogrammetric techniques in civil engineering material testing and structure monitoring.– photogrammetric engineering & remote sensing, 72/1, 39–45. doi:10.14358/pers.72.1.39 manrique, e., muci, v. & gurfinkel, m. (2007): eor field experiences in carbonate reservoirs in the united states.– spe reservoir evaluation engineering, 10, 667–686. doi:10.2118/100063-pa ngien, s.k., chin, p.q., hasan, m., ali, m.i., tadza, m.y.m. & rahman, n.a. (2016): image analysis of non-aqueous phase liquid migration in aggregated kaolin. – arpn journal of engineering and applied sciences, 11/10, 6393–6398. ngien, s.k., rahman, n.a., ahmad, k. & lewis, r.w. (2012): a review of experimental studies on double-porosity soils.– scientific research and essays, 7/38, 3243–3250. doi:10.5897/sre11.2131 ngien, s.k., rahman, n.a., bob, m.m., ahmad, k., sa’ari, r. & lewis, r.w. (2011): observation of light non-aqueous phase liquid migration in aggregated soil using image analysis.– transport in porous media, 92/1, 83–100. doi:10.1007/ s11242-011-9892-9s oostrom, m., dane, j.h. & wietsma, t.w. (2007): a review of multidimentional, multifluid, intermediate-scale experiments: flow behaviour, saturation imaging and tracer detection and quantification.– vadose zone journal, 570–598. doi:10.2136/vzj2006.0178 pao, w.k.s. & lewis, r.w. (2002): three-dimensional finite element simulation of three-phase flow in a deforming fissured reservoir.– computer methods in applied mechanics and engineering, 191/23–24, 2631–2659. doi:10.1016/s00457825(01)00420-0 peng, z., duwig, c., delmas, p., gaudet, j.p., strozzi, a.g., charrier, p. & denis, h. (2015): visualization and characterization of heterogeneous water flow in double-porosity media by means of x-ray computed tomography.– transport in porous media, 110, 543–564. doi:10.1007/s11242-015-0572-z ryzhik, v. (2007): spreading of a napl lens in a double-porosity medium.– computational geosciences, 11/1, 1–8. doi:10.1007/s10596-006-9040-8 sa`ari, r., rahman, n.a., latif abdul, n.h., yusof, z.m., ngien, s.k., kamaruddin, s.a., mustaffar, m. & hezmi, m.a. (2015): application of digital image processing technique in monitoring lnapl migration in double porosity soil column.– jurnal teknologi, 3/72, 23–29. doi:10.11113/jt.v72.4018 sitthiphat, e.a. & siam, y. (2016): investigation of average optical density and degree of liquids saturation in sand by image analysis method.– kku eng. journal, 43/s1, 147–151. doi:10.14456/kkuenj.2016.44 soil science society of america (1987): glossary of soil science terms.– soil science society of america, madison. tian, j., wang, j., hao, y., du, h. & li, x. (2014): toluene sensing properties of porous pd-loaded flower-like sno2 microspheres.– sensors and actuators, b202, 795–802. doi:10.1016/j.snb.2014.05.048 tomlinson, d.w., rivett, m.o., wealthall, g.p., & sweeney, r.e.h. (2017): understanding complex lnapl sites: illustrated handbook of lnapl transport and fate in the subsurface.– journal of environmental management, 204, 748–756. doi:10.1016/j/jenvman,2017.05045 tranngoc, t.d., lewandowska, j. & bertin, h. (2014): experimental evidence of the double-porosity effects in geo-meterials.– acta geophysica, 62, 642– 655. doi:10.2478/s11600-013-0198-x www.geologia-croatica.hr journal of the croatian geological survey and the croatian geological society 2024 | 77/2 | 179–191 | 8 figs. | 7 tabs. | 1 appendix | article history: manuscript recieved: january 2, 2024 revised manuscript accepted: march 21, 2024 available online: june 21, 2024 keywords: plomin thermal power plant, coal and slag particles, airborne dispersion, potentially toxic elements, soil composition, environmental impact 1. introduction thermal power plants are one of the largest global sources of pollution. by the combustion of coal in power plants, large amounts of various organic and inorganic pollutants are released, of which the most important are nitrogen and sulfur oxides, carbon dioxide, chlorof luorocarbons (freons), suspended fine-grained material and ''heavy metals'', referring to potentially toxic elements (shamshad et al., 2012; keating, 2001). here, all elements that could have a negative environmental impact will be considered as potentially toxic elements. istria is the largest peninsula along the croatian coastline, located in the northwest of the adriatic sea. the coal-fired plomin thermal power plant (ptpp) is situated in the central impact of coal depository and slag disposal from the plomin thermal power plant on soil composition: insights from geochemical, mineralogical, and organic petrological analyses, istria, croatia petar pongrac1, tamara troskot-čorbić2 and goran durn3,* 1 heidelberg university, institute of earth sciences, im neuenheimer feld 234-236, 69120 heidelberg, germany; (petar.pongrac@geow.uni-heidelberg.de); 2 ina – oil company, plc., exploration & production, exploration & upstream portfolio development, lovinčićeva 4, 10000 zagreb, croatia; 3* university of zagreb, faculty of mining, geology and petroleum engineering, pierottijeva 6, 10000 zagreb, croatia; (*corresponding author: goran.durn@rgn.unizg.hr) doi: 10.4154/gc.2024.07 abstract the potential impact of the open coal depository and the slag disposal of the plomin thermal power plant (ptpp) on the composition of the surrounding soils was investigated. a comprehensive approach taken included analyses of mineral composition, potentially toxic element content, their bonding properties, distribution to specific geochemical fractions in the soil and investigation of the soil organic petrology and geochemistry. the cambisols at two sampling sites exhibited a coal dust-covered upper horizon, which led us to consider these soil profiles as technosol over cambisol. for practical reasons, we have used the terms technosol and cambisol for the upper and lower parts of these profiles respectively. these formations were developed by the long-term deposition of coal dust and slag particles originating from the open coal depository and slag disposal of the ptpp, and widespread wind dispersion. the technosols, characterized by higher concentrations of lignite and lignite-subbituminous coal, showed elevated levels of c and s. analysis of the slag sample revealed a mineral composition of mullite, tridymite, graphite, haematite and an amorphous phase, indicating material formation by high temperature coal combustion. the ptpp was identified as the main contributor to the elevated concentrations of hg, mo, se, sb, u and cd. the technosols showed a significant enrichment in hg, sb, se, mo and u compared to the cambisols. in the technosols, elements such as as, cr, cu, fe, ni and zn were primarily associated with the organic and fe-mn fractions, whereas in the cambisols these elements, (with the exception of cu), are mainly associated with the organic and residual fractions. cadmium, mn and pb were predominantly bound to the carbonate and femn fractions in all the analyzed samples. the non-residual fraction has been proven to be the predominant repository for as, zn and ni in the technosols and slag, and for mn, zn and cd in the cambisols. the total content of c and s in the soils and their ratio (c/s) confirmed the higher contamination of soils in the vicinity of the ptpp with coal material. detection of the coke and soot in the slag sample substantiated its composition as bottom coal ash. in addition, the presence of the bottom coal ash particles in the cambisol underlined the airborne dispersal of the slag and its integration into the soil composition. part of the eastern coast of the istrian peninsula, in plomin bay (fig. 1). the main potential source of pollutants in the area are the products of coal combustion in the ptpp. furthermore, an open coal depository and slag (remain of coal combustion) disposal are situated next to the ptpp (fig. 2). from these deposits, fine particles of coal dust and ash are easily transported by wind to both nearby land and sea surfaces around plomin bay. the different climatic conditions in the individual parts of the peninsula (filipčić, 1992; ogrin, 1995) and the gradual uplift of the carbonate plateau from the south and southwest to the northeast (velić et al., 1995) largely influenced the diversity of soils on the peninsula. the study area has been exposed to the harmful effects of mining (historical coal and bauxite mining, mining of technical and architectural building stone and brick clay) and constant mailto:petar.pongrac@geow.uni-heidelberg.de mailto:goran.durn@rgn.unizg.hr g eo lo gi a c ro at ic a 180 geologia croatica 77/2 contamination with coaly material and coal ash resulting from coal combustion at the ptpp. continuous and long-term coal combustion has been proven to largely influence pollution of adjacent soils (e.g., sun et al., 2010, li et al., 2014, rodriguez-iruretagoiena et al., 2015). miko et al., (2003) determined that soils near the plomin thermal power plant (ptpp) were enriched in cr, ni, v, mn, cu, cd and mo. relatively high sorption capacity of fe and mn oxyhydroxides present in those soils had a crutial role on retention of potentially toxic elements in soil. prohić & miko (1998) compared the concentrations of se, as, v, cr, ni and zn in the soil in the vicinity of the ptpp with concentrations of the same elements in soils on risnjak mountain, near the city of rijeka (croatia). concentrations of all these elements except as were significantly higher in soils near the ptpp. another negative environmental impact of the ptpp is also visible from relatively high levels of pollution of the soils near the ptpp with sulfur, pahs and the potentially toxic elements cd and se, after the continuous combustion of superhigh-organic-sulfur coal (raša coal), used from 1970 until 2000 (medunić et al., 2016a,b; malenšek et al., 2017). more details on the geochemical characteristics of the raša coal can be found in medunić et al., (2016b). water extracts of the most polluted soils and ash samples had shown significant cytotoxic effects on fish cells. although not statistically significant, the genotoxic effects were also distinct. fiket et al., (2016) investigated the influence of the ptpp on the surrounding environment regarding ree concentrations and their normalized counterparts in soil, coal, ash and slag samples. although the resulting ree concentrations in soils near the ptpp were not of concern, soil samples closer to the ptpp showed elevated ree concentrations compared to samples from further away, clearly indicating a negative impact on the environment. petrović et al. (2023) investigated coal combustion residue (coal ash) landfill situated in štrmac, istria, near the ptpp. this coal ash is a residue from the local raša coal. it was found that the landfill is characterized by both 2nd and 3rd stages of coal ash landfill evolution. the aim of this study was to evaluate and interpret the possible impact of the open coal depository and slag disposal of the ptpp on the composition of the adjacent soils. for this purpose, we conducted a thorough investigation of the mineral composition, content of potentially toxic elements and their bonding and distribution via certain geochemical fractions in the soils, and the organic petrology-geochemistry. the results have provided a detailed background in relation to the coaly material. within the additional micromorphological study of the soils, we investigated the influence of coal/slag particle deposition on the internal morphology of the soils. 2. materials and methods 2.1. field work the sampling was carried out in the spring of 2013, at five locations around the ptpp (figs. 2 and 3). seven soil samples and a sample of the slag from the open disposal next to the ptpp were collected. soil sampling and characterization were done in accordance with fao (2006). at location p1 (fig. 3-a), the soil profile was open to a depth of 30 cm, and the soil samples were taken from the dark coloured surface horizon (sample p1-a; depth range 0-20 cm) and from depth range 20-30 cm (sample p1-b) (fig. 3-b). location p2 (fig. 3-c), where two samples were taken (0-40 and 40-80 cm respectively), is 300 m west of the ptpp, at almost twice the altitude of location p1. the upper part of the soil profile differed from the lower part by its distinctly darker colour and characteristic bituminous figure 1. a) location of croatia in europe. b) location of the istrian peninsula, study area and the ptpp within croatia. g eologia c roatica 181pongrac et al.: impact of coal depository and slag disposal from the plomin thermal power plant on soil composition: insights from geochemical ... smell (fig. 3-d). location p3 (fig. 3-e and f) was at the open disposal of slag material, situated next to the ptpp, from where the sample of slag was collected (sample p3). the farthermost location p4 (fig. 3-g) was situated in coniferous forest, from where a sample of the surface soil horizon (sample p4) was taken. at location p5 (fig. 3-h), (located near to the ptpp in the south), an open soil profile 35 cm deep provided undisturbed samples from a depth range 4-12 cm and 19-28 cm, using kubiena boxes. all the investigated soil profiles were situated on the carbonate bedrock (nummulitic limestones). 2.2. laboratory methods for the purposes of laboratory examinations, a portion of each disturbed soil sample was crushed and sieved through a 2 mm sieve for chemical and mineralogical analyses. for the x-ray powder diffraction (xrd), the sequential extraction procedure figure 2. satellite images of the region surrounding the ptpp showing the sampling locations and the open coal depository and slag disposal locations (source: google earth; 2016). figure 3. sampling locations: a) soil profile p1; b) samples from location p1; c) outcrop of limestone with soil on the top at location p2; d) sample of dark upper horizon at location p2; e) open slag disposal at location p3; f) sampling at location p3; g) surface soil horizon at location p4; h) soil profile p5. g eo lo gi a c ro at ic a 182 geologia croatica 77/2 (sep) and the chemical analysis, sieved samples were then ground to a fine-powder in an agate mill, while granulometric analysis and organic petrology-geochemistry analyses were carried out using sieved samples. from undisturbed samples p5-a and p5-b, taken with the kubiena boxes, soil thinsections were made. those samples were only used for the micromorphological analysis. the distribution of soil particle sizes was determined using a laser diffractometer shimadzu sald 2300 and interpreted according to the fao (2006). prior to the analysis, organic matter was removed from the samples using hydrogen peroxide (h2o2) as described by tributh & lagaly (1986). sodium hexametaphosphate was used as a decoagulant. the sample of slag (p3) was not subjected to granulometric analysis. qualitative phase analysis was performed using x-ray diffraction, with a graphite monochromator and cukα radiation (diffractometer philips pw 1830). both the powdered samples (fraction < 2 mm) and the clay fraction (< 2 μm) were examined. the < 2 μm fractions were separated by sedimentation in cylinders and quantitatively obtained after the appropriate settling time. the xrd patterns of the clay fraction were obtained after the following treatments: (a) k-saturation, (b) mg-saturation, (d) k-saturation and ethylene glycol solvation, (e) mgsaturation and ethylene glycol solvation, (f) heating for two hours at 300 and 550°c. the clay minerals were determined following the methods of thorez (1975), brown (1961), brindley & brown (1980), moore & reynolds (1997) and wilson (1987). the chemical composition of the samples was determined at the commercial acme analytical laboratory, canada. the major element oxides were determined by icp-emission spectrometry following a lithium metaborate/tetraborate fusion and diluted nitric acid digestion. trace element content was determined by the icp-mass spectrometry following a lithium metaborate/tetraborate fusion and nitric acid digestion (ba, co, cu, ni, pb, u, v, zn) or following digestion in aqua regia (as, cd, hg, mo, se). the lithium borate fusion methods provide total element content while digestion in aqua regia provides a near-total content. as part of the analysis, the total amounts of carbon and sulfur were measured by the leco analyzer (combustion and infrared detection technique). a sequential extraction procedure was performed in order to assess the main bonding sites of elements in the studied soils, according to a modified sediment leaching scheme (tessier et al., 1979; hall et al., 1996), in five steps of separation: (1) adsorbed/exchangeable fraction (ad), (2) carbonated (calcareous) fraction (cc); (3) fe and mn oxyhydroxides fraction (femn); (4) organic fraction and finally (5) the residual fraction (res). within this framework, concentrations of as, cd, cr, cu, fe, mn, ni, pb and zn were measured by atomic absorption spectrometry (aas, aanalyst 700), for each of the aforementioned fractions. all elements except as were measured by the flame technique, while concentrations of as were measured by the hydride technique. the samples of dark coloured top soil (p1-a and p2-a) and sample of slag were subjected to the rockeval pyrolysis, following espitalie et al., (1985). the analyses were also performed on extracted samples. the extractable organic matter (eom) of the powdered samples was determined by 36-hour soxhlet extraction with chloroform. the extractable organic matter concentrate obtained after the hcl/hf/zncl2 treatment of soil was examined microscopically (see schwab, 1990) for all types of sample. the organic matter was examined in transmitted and blue fluorescent light using an olympus bx51 and zeiss axio imager microscope, respectively. the leitz mpv3 microscope photometer and the zeiss axio imager microscope equipped with the msp 210 microscope spectrometry system were used for examination in white reflected light and vitrinite reflectance measurements (oil immersion, 546 nm wavelengths). the undisturbed sample from depth range 4-12 cm (p5-a) represented a transition from the a-horizon to the bw-horizon, while sample p5-b from depth range 19-28 cm represents the deeper bw-horizon. the thin-sections for micromorphological analysis were prepared in the thomas beckmann laboratory (schwülper–lagesbüttel, germany). micromorphological interpretation was done according to bullock et al., (1985) and stoops (2003), using the leica dm/lsp petrographic microscope with plane-polarized (ppl) and cross-polarized light (xpl). 3. results and discussion based on the highly generalized fao–unesco soil map of croatia (scale 1:1.000,000 – bogunović et al., 1998), the investigated soils (locations p1, p2, p4 and p5) were recognized as cambisols. at sites p1 and p2, the upper part of the cambisols was covered with anthropogenic material (coal dust). due to the assumed and remarkable contamination with coal particles (in terms of color, touch and smell of the soil), we considered these soil profiles as technosol over cambisol. however, in the text we will use the terms technosol and cambisol for the upper (p1/p2-a) and lower (p1/p2-b) parts of these profiles, respectively. the general morphological chartable 1. morphological characteristics of the investigated soils and slag. soil profile location altitude (masl) depth (cm) sample soil color (munsell soil color chart, 2000) soil category p1 32.1 0-20 p1-a 10yr 2/1 technosol over cambisol 20-30 p1-b 10yr 3/4 p2 68.6 0-40 p2-a 10yr 2/1 technosol over cambisol 40-80 p2-b 7,5yr 4/4 p3 6.5 – p3 gley 3/n – p4 87.2 0-15 p4 7,5yr 3/3 cambisol p5 15.0 0-6 p5-a (4-12 cm) 5yr 3/4 cambisol 6-35 p5-b (19-28cm) 5yr 4/4 g eologia c roatica 183pongrac et al.: impact of coal depository and slag disposal from the plomin thermal power plant on soil composition: insights from geochemical ... acteristics of the soil profiles are listed in table 1. given the broader elevation along sampling sites p1 and p2 together with the fact that the sampling sites are at a higher elevation than the ptpp, it can be assumed that the topography acts as a geomorphological barrier to the most common wind direction from sea to land (approximately e – w; filipčić, 1992). this elevated part can therefore easily trap small airborne particles of coal dust that originated from the open disposal areas. in addition, the entire surrounding area probably had a similar barrier effect, as the ptpp is at a notably lower elevation compared to its surrounding. the technosol layers were therefore most likely formed during years of constant sedimentation of the coal and slag particles. 3.1. particle size distribution the analyzed soil profiles were predominantly composed of silt fraction sized particles (fig. 4). soil samples p1-a, p2-a and p2-b are more enriched in the sand-sized content compared to samples p1-b and p4. the technosols (p1-a and p2-a) contain smaller amounts of the clay fraction than the underlying cambisols. 3.2. mineral composition results of the qualitative mineralogical analysis of the investigated soils are shown in table 2. quartz, phyllosilicates, calcite, and haematite were determined in both the technosols and the cambisols. plagioclase, k-feldspar, and goethite were detected only in the cambisols while the technosols contain dolomite and a relatively high amount of organic material, as evident from the broad diffusive maximums in the range between 20-30° 2θ, and the results of rockeval pyrolysis (see section 3.5). the slag sample is composed of quartz, mullite, tridymite, graphite, haematite and an amorphous phase. these latter two mineral assemblage represent an inorganic residue after the combustion of coal (coal combustion products) at high temperatures (white & case, 1990; vassilev et al., 2003). the clay fractions of the technosols and cambisols are also similar and contain quartz, kaolinite, chlorite and illitic material (table 3). the mixed-layer clay minerals and vermiculite were detected only at site p2. 3.3. major element oxides and trace elements the content of the major element oxides and total sulfur and carbon in the investigated materials is shown in table 4. the figure 4. cumulative granulometric composition of the investigated soil samples (according to folk, 1980). table 2. qualitative mineral composition of soils and slag (fraction < 2 mm). sample quartz plagioclase k-feldspar phyllosilicates calcite dolomite goethite haematite trydimite, mulite and graphite aoic* p1-a + + + + + + p1-b + + + + + + + p2-a + + + + + + p2-b + + + + + + + p3 + + + + p4 + + + + + + + *aoic – amorphous organic and inorganic compounds table 3. qualitative mineral composition of soils (fraction < 2 μm). sample quartz kaolinite chlorite illitic material vermiculite mlm* p1-a + + + p1-b + + + + p2-a + + + + + p2-b + + + + + + p4 + + + + *mlm – mixed layer clay mineral g eo lo gi a c ro at ic a 184 geologia croatica 77/2 technosols contain significantly less sio2 compared to the underlying cambisols. it is similar with the other components, with the exception of cao, probably due to the slightly higher content of calcite and the presence of dolomite. the lower content of sio2 and al2o3 in the technosols indicates a significantly lower content of phyllosilicates compared to the underlying cambisols. technosols have an extremely high sulfur and carbon content compared to the underlying cambisols, which is direct evidence of the soil contamination with coaly material. severe pollution of the soils next to the ptpp with sulfur has already been well described in medunić (2016a) and malenšek et al. (2017). sample p1-b, which was taken closer to the ptpp, contains significantly more carbon and sulfur than sample p2-b, which was farther from the ptpp. the slightly higher carbon value in sample p4 was most likely associated with the organic material from plant residues. this is reflected by a very low s content and a high c/s ratio. the slag sample consists mainly of sio2, al2o3, fe2o3 and carbon (table 4), which corresponds to its mineral composition (sio2 stands for quartz, tridymite and mullite, al2o3 for mullite, fe2o3 for haematite and carbon for graphite; table 2). concentrations of the trace elements are listed in table 5. in comparison to the cambisols, the technosols show enrichment in hg, mo, sb, se and u, while exhibiting a depletion in as, ba, ni, cd, co, cr, cu and v. the slag contained a high level of ba. all the aforementioned elements are common potentially toxic elements released during combustion of coal (ovec, 2009; toppin ording, 2009; fuge, 2005). rodriguez-iruretagoiena et al. (2015) found high concentrations of as, co, cr, cu, fe, mn, mo, pb, sb, sn, tl, v and zn in some specific areas around the power plant, while li et al. (2014) determined cd, pb, cu, zn, hg, as, and ni as the most hazardous soil pollutants from coal mining areas. both of these ranges greatly overlap the range of elements found in this research. the average concentrations of hg and mo in the technosols were almost double the average concentrations in the cambisols (table 5). in the case of hg, all values, with the exception of the slag sample, are significantly higher than the values for the coastal region and the whole of croatia (figure 5). the ratio between the average concentration in the cambisol samples p1-b and p2-b (xb) and the most distant cambisol sample p4 can be used to estimate the relative release of a particular element from the coal dust. the data indicate an enrichment of hg in the coal dust, but it is difficult to estimate the release of hg from the coal and bonding to the soil fractions because the ratio x̄ b/p4 was < 1. the increased hg and mo content in the soil is a consequence of anthropogenic input. the distribution of se and sb indicates a similar conclusion. due to the x̄ b/p4 ratio of ~ 1 and the higher sb content in the upper part of the technosol, the sb appears to be relatively strongly bound to the coal. the amount and distribution of se and u also indicate that the coal particles were enriched with se and u and that their content was higher at shorter distances from the ptpp (table 5). in addition to the coal dust from the technosols, the slag sample (p3) also has a relatively high u content, indicating that a large proportion of the u remained in the slag after coal combustion. it is also known that mining and the use of coal in industry and power plants are the main source of table 4. content of major elements oxides in studied samples, including total c and s (wt %). sample sio2 al2o3 fe2o3 mgo cao na2o k2o tio2 p2o5 mno cr2o3 c s loi* p1-a 5.61 2.23 1.49 0.83 3.00 0.16 0.21 0.12 0.05 0.02 0.007 63.9 9.14 84.6 p1-b 45.75 16.27 7.21 1.3 1.89 0.45 1.64 0.90 0.16 0.25 0.035 8.04 0.62 23.9 p2-a 7.45 2.93 1.50 0.99 5.64 0.18 0.27 0.16 0.04 0.04 0.008 57.9 8.86 75.8 p2-b 53.10 18.59 7.94 1.66 1.41 0.58 1.83 1.02 0.11 0.24 0.036 1.17 0.05 13.2 p3 56.49 15.16 9.11 1.42 1.97 0.59 1.60 0.68 0.13 0.07 0.016 9.4 0.13 12.5 p4 37.10 14.95 6.34 1.37 2.85 0.34 1.28 0.78 0.22 0.18 0.037 12.2 0.14 34.3 *loi – loss on ignition table 5. content of trace elements in studied samples (mg/kg; bdl –below detection limit). element p1-a p1-b p2-a p2-b p3 p4 as 2.3 18.8 2.7 20.3 1.9 16.4 ba 90 349 57 381 849 285 cd 0.8 5.3 1 4.2 bdl 4.9 co 3.7 29.7 4.3 30 18.2 19.7 cu 12.3 58.5 11.3 49.4 40.1 35.3 hg 0.27 0.17 0.35 0.13 0.1 0.22 mo 4 3.4 3.2 1.5 1.1 1.2 ni 21.5 83 22.4 92.3 9.6 59.8 pb 18.5 56.4 18.8 36.9 1.5 62.7 sb 2.5 0.4 0.8 0.3 0.3 0.3 se 8.3 5.8 9.1 bdl bdl bdl u 11.7 7.3 6.3 4.1 5.7 3.1 v 84 389 70 359 209 273 zn 77 89 32 85 26 92 g eologia c roatica 185pongrac et al.: impact of coal depository and slag disposal from the plomin thermal power plant on soil composition: insights from geochemical ... anthropogenic input of toxic uranium into the environment and ecosystems (atsdr, 1999). judging from the distribution, the presence of cd in the studied soils is probably due to the impact of the power plant, although this is not evident from the distribution in the technosols. this can be explained by the mobility of cd, as discussed in section 3.4. we consider that hg, mo, sb, se and u as well as cd are predominantly of anthropogenic origin and their distribution indicates the negative impacts of the ptpp. figure 5. illustrates the variation in concentrations of respective elements obtained through geochemical analysis relative to the statistical values of the same elements' concentrations for the coastal (adriatic) part of croatia and the entire croatian state, as per the geochemical map of the republic of croatia (halamić & miko, 2009). the concentrations of as, ba and ni in the investigated cambisols are at the level of the median values for the coastal area and the whole of croatia, while the concentrations of cd, co, cr, cu, mn and v are significantly higher. this is particularly true for cd, which is 5 to 10 times higher compared to the coastal and the whole of croatia. these results agree with those of miko et al. (2003), who found that soils near the ptpp were enriched with cr, ni, v, cu, cd and mo, and confirm that anthropogenic pollution is related to the ptpp. figure 5. comparison of the results from geochemical analysis and median values of their concentrations in coastal areas (green circles) and the whole (blue squares) of croatia according to the geochemical map of croatia (halamić & miko, 2009). variation of average concentrations from the geochemical analysis relative to the referent values of halamić & miko, 2009 are presented in %. results are presented separately for average values of technosol samples p1-a and p2-a (xa) and cambisol samples p1-b and p2-b (xb), as well as for the slag and the most distant cambisol sample p3 and p4, respectively. the empty green circles mark the values out of the scale. g eo lo gi a c ro at ic a 186 geologia croatica 77/2 3.4. sequential extraction analysis by determining the bonding sites of elements in different geochemical fractions of the soil, an interpretation of their behavior and bioavailability can be obtained. this leads to assessment of their environmental risk and possibility of remobilization. results are shown in figure 6 and appendix 1. the distribution of the analyzed elements among sequential fractions in the technosols and cambisols is different for as, cr, cu, fe, ni and zn. in the technosols, these elements are mainly associated with the organic and fe-mn fractions, while in the cambisols, they are mainly bound to the organic and residual fractions (with the exception of cu). copper in the figure 6. distribution of the measured elements within sequential extraction fractions of the investigated samples, expressed in mg/kg (see text for explanation of the fractions). g eologia c roatica 187pongrac et al.: impact of coal depository and slag disposal from the plomin thermal power plant on soil composition: insights from geochemical ... cambisols is mainly concentrated in the fe-mn and residual fractions. cadmium, mn and pb are concentrated in the carbonate and fe-mn fractions in all the soil samples. it is important to note that cd is mainly bound to the carbonate fraction and partly also to the adsorbed/exchangeable fraction. this may explain higher cd but also pb values in the cambisols that are below the technosols (table 5). depending on the relative bioavailability of the elements, table 6 shows a relationship between (1) the sum of the element concentrations in the first four steps of the sequential extraction (adsorbed, carbonate, fe-mn oxyhydroxides and organic fraction) and (2) the total concentration of the element determined by the icp techniques. the highest ratio (1) / (2) (expressed as a percentage) indicates a relatively higher bioavailability of the element in the soil studied, as this means that a greater proportion of the total content of the element was bound to fractions from which it could be more easily released. since the bioavailability depends also on many other parameters, this measure is very relative. relative bioavailability decreases as follows: upper part of technosols: zn = as > ni > cr > mn > cd > pb > fe > cu other soil samples: mn > zn > cd > fe > ni > pb > cr > cu > as slag: as > zn > ni > cu > mn > fe > cr > cd = pb. distribution of these elements is in a good accordance with the ones estimated by rodriguez-iruretagoiena et al. (2015) and li et al. (2014). unfortunately, we cannot say anything about the bioavailability of hg, mo, sb, se and u, as we did not have the possibility to perform the sequential extractions for these elements. 3.5. organic petrology-geochemistry the results of the rockeval pyrolysis are shown in table 7. the technosols (p1-a and p2-a) are extremely rich in organic matter (toc). pyrolysis data reveal a high generation potential (s2) and a high content of free hydrocarbons (s1) that are still present in samples after extraction. the organic content in the slag sample is also increased, but not with the high range of technosols. in technosols dark and structured fragments with orangeyellowish to brownish fluorescence predominate (fig. 7 a, b). there was no change in maceral composition in the extracted samples. structured particles are dominantly represented with the macerals huminite and vitrinite (huminite/vitrinite group) and sporadically with traces of macerals of the inertinite group, fusinite and semifusinite (stach et al., 1982; taylor et al., 1998). these coaly particles according to the vitrinite reflectance measurements measured on huminite (from 0.35 to 0.40% ro) belonged to lignite (fig. 7 c), or lignite a to subbituminous coal c (american terminology), or dull to bright brown coal (german terminology) due to a slightly increased vitrinite reflectance in p2-a sample (0,45 % ro). in the maceral composition of the slag particle (p3) structured particles are also predominately huminite (~70% vol). the rest of the composition is represented with macerals of the inertinite group and products of combustion, soot and coke (fig. 7 d). the vitrinite reflectance of the huminite particles is from 0.3 to 0.4 %ro. these particles have no fluorescence, except for several cavities. the coke was probably formed by the destructive distillation of lignite at high temperatures. the conditions described were mainly achieved during combustion of lignite at the ptpp, where the coke was disposed of as part of the slag material. table 6. ratio x100 as a function of relative bioavailability of elements in soils and slag. sample as cd cr cu fe mn ni pb zn p1-a 100 87.5 67.06 42.93 56.24 61.44 93.49 89.73 96.1 p1-b 8.58 63.77 43.86 37.78 50.19 70.03 47.67 47.78 63.55 p2-a 94.13 39 70.42 38.41 62.61 65.34 84.51 32.02 100 p2-b 9.12 49.29 37.29 44.21 50.07 65.45 47.12 46.23 52.35 p3 100 0 2.52 58.43 5.69 10.43 63.54 0 63.88 p4 10.36 42.5 43.62 27.39 49.45 65.62 49.88 48.37 60.87 table 7. rockeval pyrolysis results. sample toca (mass %) s1 b hc (mg) samp. (g) s2 c hc (mg) samp. (g) s3 d co2 (mg) samp. (g) tmax (°c) s2/s3 hie hc (mg) toc (g) oif co2 (mg) toc (g) mincg (mass %) p1-a 57.61 19.46 218.96 6.83 418 32.06 380 12 1.78 p1-aeks 52.09 8.03 177.98 6.46 424 27.55 342 12 1.13 p2-a 55.93 20.04 220.92 5.59 421 39.52 395 10 1.81 p2-aeks 52.08 6.59 183.84 5.76 423 31.92 353 11 1.91 p3 3.28 0.14 4.71 0.21 429 22.43 144 6 0.39 p3eks 5.95 0.33 6.41 1.07 430 5.99 108 18 0.38 atoc – total organic carbon bs1 – free hydrocarbons content cs2 – content of hydrocarbons formed during kerogen cracking ds3 – co2 amount formed during kerogen cracking ehi – hydrogen index foi – oxygen index gminc – mass of inorganic carbon g eo lo gi a c ro at ic a 188 geologia croatica 77/2 3.6. micromorphology micromorphological features in both samples fromthe cambisol profile (p5) are very similar. the microstructure was granular to vuggy and vuggy/cracked (fig. 8 a and b), with a moderate to highly developed degree of pedality. the pore space was characterized by irregular cavities and channels. semi-angular pedorelicts were rarely present (fig. 8 c), as well as particles of bottom coal ash (fig. 8 e; cca. 5% vol). the bottom coal ash particles are gray-coloured fragments, ranging up to 6 mm in diameter, containing rounded caverns (fig. 8 f) which were presumably the result of rapid cooling after combustion. due to the high content of goethite and subordinate content of haematite (durn et al., 2001; singer et al., 1998), the matrix was brownish-red in colour/ rounded, branched and irregular iron-oxide impregnative nodules were also observed (fig. 8 d). the lack of recent and sub-recent clay coatings in the pore spaces of the soil indicates that in the past, the soil was used as farmland (cultivable soil) (durn, 2003). the presence of bottom coal ash particles in the cambisol indicates the aerial dispersion of slag and its involvement in the soil composition. 4. conclusion this research was concerned with the possible influence of the open coal depository and the slag disposal of the plomin thermal power plant (ptpp) on the composition of the adjacent soils. since the cambisols at sites p1 and p2 were covered with coal dust in the upper part, we considered these soil profiles as technosols over cambisols. they were most likely formed by a relatively long-term deposition of coal dust and slag particles from the ptpp. the total c and s content in the soils and their ratio (c/s) confirmed that the soils in the vicinity of the ptpp were highly contaminated with coal and slag material, while the detection of the coke and soot in the slag sample confirmed that the slag consisted of bottom coal ash. the presence of the bottom coal ash particles in the cambisol samples indicates the airborne dispersion of the slag and its involvement in soil composition. the coal and slag particles were dispersed from the open coal depository and slag disposal, respectively. the technosols contain particles of lignite and lignite-subbituminous coal, which significantly increased their c and s content. in the slag sample, the mineral association of mullite, tridymite, graphite, haematite and amorphous phases proved that the material was formed by the process of coal combustion at high temperatures. mercury, mo, se, sb, u and cd are predominantly of anthropogenic origin and their distribution directly indicates the negative influence of the ptpp. in the technosols, as, cr, cu, fe, ni and zn are mainly bound to organic and fe-mn fractions, while in the cambisols these elements are mainly bound to the organic and residual fractions (with minor variations of cu), suggesting that it is relatively likely that these elements are mobilized in the technosols containing comparatively lower amounts of clay minerals and retained in the cambisols with figure 7. photomicrographs of a) huminite particles in transmitted light (sample p1-a); b) huminite particles in blue fluorescent light (sample p1-a); c) huminite particle in oil immersion (reflected light; sample p1-a); d) fusinite particle with soot and coke, in oil immersion (reflected light; sample p3). g eologia c roatica 189pongrac et al.: impact of coal depository and slag disposal from the plomin thermal power plant on soil composition: insights from geochemical ... a greater proportion of clay minerals. cadmium, mn and pb are mainly associated with carbonate and fe-mn fractions in all the analyzed samples, which increases their potential bioavailability. the non-residual fraction was the most abundant sink for as, zn, mn and ni in the technosols and for mn, zn and cd in the cambisols, which is in strong agreement with the results of rodriguez-irureta goiena et al. (2015) and li et al. (2014). the accumulation of these elements in non-residual, especially organic fractions of the cambisols proves the negative environmental impact of the ptpp and warns of their potential uptake into the ecosystem by vegetation. further research may investigate the bioavailability of potentially hazardous elements and the likelihood of their uptake into the ecosystem. acknowledgement this work has been supported in part by the croatian science foundation (project no. ip-2019-04-8054). references atsdr (agency for toxic substances and disease registry) (1999): toxicological profile for uranium.– u.s. department of health and human services, public health service, agency for toxic substances and disease registry, atlanta, ga. bogunović, m., vidaček, ž., racz, z., husnjak, s., špoljar, a. & sraka, m. (1998): fao/unesco croatian soil map, small scale 1:1.000,000.– university of zagreb, faculty of agriculture, project monitoring agriculture with remote sensing. brindley, g.w. & brown, g. (1980): crystal structures of clay minerals and their x ray identification.– mineralogical society of great britain and ireland, london. doi: 10.1180/mono-5 brown, g. (1961): the x-ray identification and crystal structures of clay minerals.– mineralogical society, london bullock, p., fedoroff, n., jongerius, a., stoops, g., tursina, t. & babel, u. (1985): handbook for soil thin section description.– waine research, albrighton, 152 pp. durn, g. (2003): terra rossa in the mediterranean region: parent materials, composition and origin.– geologia croatica, 56/1, 83–100. doi: 10.4154/ gc.2003.06 figure 8. soil photomicrographs from sample p5-a: a) granular to vuggy microstructure; b) vuggy/cracked microstructure; c) fragment of pedorelict (red circle); d) rounded and impregnative (smaller photo) fe-nodules; e) bottom coal ash particle; f) cavern on a bottom coal ash particle. g eo lo gi a c ro at ic a 190 geologia croatica 77/2 durn, g., slovenec, d. & čović, m. (2001): distribution of iron and manganese in terra rossa from istria and its genetic implications.– geologia croatica, zagreb, 54/1, 27–36. doi: 10.4154/gc.2001.03 espitalie, j., deroo, g. & marquis, f. (1985): rock eval pyrolysis and its applications.– institut francais du petrole. fao (2006): guidelines for soil description, 4th edition.– fao, rome, 97 p. fiket, ž., medunić, g. & kniewald, g. (2016): rare earth elements distribution in soil nearby thermal power plant.– environ. earth. sci. 75, 598. doi: 10.1007/s12665-016-5410-2 filipčić, a. (1992): klima hrvatske.– geografski horizonti, 38/2, 26–35. folk, r.l. (1980): petrology of sedimentary rocks.– hemphill publishing, austin, tx, 182 p. fuge, r. (2005): anthropogenic sources.– in: selinus o. (ed.): essentials of medical geology – impacts of the natural environment on public health, british geological survey, 43–60. hall, g.e.m., vaive, j.e., beer, r. & hoashi, m. (1996): selective leaches revisited, with emphasis on the amorphous fe oxyhydroxide phase extraction.– journal of geochemical exploration, 56/1, 59–78. doi: 10.1016/0375-6742(95)00050-x halamić, j. & miko, s. (ed.) (2009): geokemijski atlas republike hrvatske (geochemical map of republic of croatia).– hrvatski geološki institut (croatian geological survey), zagreb, 87 p. keating, m. (2001): cradle to grave: the environmental impacts from coal.– clean air task force, boston, 8 p. li, z., ma, z., van der kuijp, t.j., yuan, z. & huang, l. (2014): a review of soil heavy metal pollution from mines in china: pollution and health risk assessment.– science of the total environment, 468, 843–853. doi: 10.1016/j.scitotenv.2013.08.090 malenšek, n., medunić, g., lojen, s., & zupančič, n. (2017): sulphur isotopes in soil around the thermoelectric power plant plomin (croatia).– in: ionete, r.(ed.): book of abstract: esir isotope workshop xiv, băile govora, vâlcea, 133–134. medunić, g., ahel, m., božičević mihalić, i., gaurina srček, v., kopjar, n., fiket, ž., bituhe, t. & mikac, i. (2016a): toxic airborne s, pah, and trace element legacy of the superhigh-organic-sulfur raša coal combustion: cytotoxicity and genotoxicity assessment of soil and ash.– science of the total environment 566–567, p; 306–319 medunić, g., rađenović, a., bajramović, m., švec, m. & tomac, m. (2016b): once grand, now forgotten: what do we know about the superhigh-organic-sulfur raša coal?– rudarsko-geološko-naftni zbornik, 31/3, doi: 10.17794/rgn.2016.3.3 miko, s., durn, g., adamcová, r., čović, m., dubíková, m., skalský, r., kapelj, s. & ottner, f. (2003): heavy metal distribution in karst soils from croatia and slovakia.– environmental geology, 45, 262–272 moore, d.m. & reynolds, r.c. jr. (1997): x-ray diffraction and the identification and analysis of clay minerals. 2nd ed.– oxford university press, oxford. ogrin, d. (1995): podnebje slovenske istre.– annales, koper, 381 pp. ovec – ohio valley environmental coalition (2009): heavy metals naturally present in coal & coal sludge.– sludge safety project. prohić, e. & miko, s. (1998): distribution of selected elements in soils in the vicinity of coal burning power plant ''plomin'', istria, croatia. erdwissenschaftliche aspekte des umweltschutzes, tagungsband.– in: sauer, d. (ed): österriechisches forschungsund prüfzentrum arsenal ges. m. b., wien, 319–324. regulations on agricultural land protection against pollution.– ministry of agriculture, republic of croatia, 2014. index: nn 9/14) rodriguez-iruretagoiena, a., de vallejuelo, s.f.o., gredilla, a., ramos, c.g., oliveira, m.l.s., arana, g., de diego, a., madariaga, j.m. & silva, l.f.o. (2015): fate of hazardous elements in agricultural soils surrounding a coal power plant complex from santa catarina (brazil).– science of the total environment, 508, 374–382. doi: 0.1016/j.scitotenv.2014.12.015 schwab, k.w. (1990): visual kerogen assessment.– in: int. symposium on organic petrology, zeist, 10-14. shamshad, a., fulekar, m.h. & bhawana, p. (2012): impact of coal based thermal power plant on environment and its mitigation measure.– international research journal of environment sciences, 1/4, 60–64. singer, a., schwertmann, u. & friedl, j. (1998): iron oxide mineralogy of terre rosse and rendzinas in relation to their moisture and temperature regimes.– european journal of soil science, 49, 385–395. doi: 10.1046/j.1365-2389.1998.4930385.x stach, e., mackowsky, m.t.h., teichmüller, m., taylor, g.h., chandra, d. & teichmüller, r. (1982): coal petrology.– gebrüder borntraeger, berlin-stuttgart, 535 p. stoops, g. (2003): guidelines for analysis and description of soil and regolith thin sections.– soil science society of america, inc. madison, wisconsin. sun, r., liu, g., zheng, l., & chou, c. l. (2010): geochemistry of trace elements in coals from the zhuji mine, huainan coalfield, anhui, china.– international journal of coal geology, 81/2, 81–96. doi: 10.1016/j.coal.2009.12.001 taylor, g.h., teichmüller, m., davis, a., diessel, c.f.k., littke, r. & robert, p. (1998): organic petrology.gebrüder borntraeger, berlin-stuttgart, 704 p. tessier, a., campbell, p.g.c. & bisson, m. (1979): sequential extraction procedure for the speciation of particulate trace metals.– analytical chemistry, 51/7, 844–851. doi: 10.1021/ac50043a017 thorez, j. (1975): phyllosilicates and clay minerals: a laboratory handbook for their x-ray diffraction analysis.– editions g. lelotte, liege. toppin ording, e. (2009): heavy metals and coal: carbon footprint aside, coal is not environmentally friendly.– suite 101. tributh, h. & lagaly, g. (1986): aufbereitung und identifizierung von bodenund lagerstättentonen: i. aufbereitung der proben im labor.– git fachz. lab. 30, 524–529. vassilev, s.v., menendez, r., alvarez, d., diaz-somoano, m. & martineztarazona, m.r. (2003): phase-mineral and chemical composition of coal fly ashes as a basis for their multicomponent utilization. 1. characterization of feed coals and fly ashes.– fuel, 82/14, 1793–1811. doi: 10.1016/s0016-2361(03)00123-6 velić, i., tišljar, j., matičec, d. & vlahović, i. (1995): opći prikaz geološke građe istre.– in: vlahović, i. & velić, i. (ed-): excursion guidebook; first croatian geological congress, zagreb, 5–30. white, s.c. & case, e.d. (1990): characterization of fly ash from coal-fired power plants.j. mater. sci. 25, 5215–5219. doi: 10.1007/bf00580153. wilson, m.j. (1987): a handbook of determinative methods in clay mineralogy.– verlag blackie, glasgow and london, 308 p. g eologia c roatica 191pongrac et al.: impact of coal depository and slag disposal from the plomin thermal power plant on soil composition: insights from geochemical ... appendix 1. distribution of measured elements within sequential fractions of the soils and slag samples (bdl – below detection limit). fraction sample as (µg/kg) cd (mg/kg) cr (mg/kg) cu (mg/kg) fe (mg/kg) mn (mg/kg) ni (mg/kg) pb (mg/kg) zn (mg/kg) ad p1-a 28.61 0.06 bdl 0.17 3.85 6.21 bdl bdl 3.21 p1-b bdl 0.20 bdl 0.36 1.79 13.55 bdl bdl 0.21 p2-a bdl bdl bdl 0.15 1.36 3.15 bdl bdl 0.17 p2-b bdl bdl bdl 0.44 0.41 1.28 0.56 bdl 0.11 p3 324.86 bdl bdl 3.85 0.00 3.41 0.45 bdl 4.34 p4 bdl 0.07 bdl 0.31 1.18 26.13 0.44 bdl 0.15 cc p1-a 263.63 0.64 0.51 0.02 43.24 53.13 1.80 8.05 19.10 p1-b bdl 2.31 1.42 2.27 46.80 622.81 2.05 6.06 3.06 p2-a 111.05 0.39 0.70 0.37 19.44 108.53 1.74 3.47 5.16 p2-b bdl 1.07 1.28 3.68 24.35 193.37 2.18 1.02 1.01 p3 984.59 bdl 0.29 12.17 209.08 8.52 1.42 0.00 5.07 p4 18.68 1.65 1.84 0.72 32.03 541.33 1.18 9.54 4.53 femn p1-a 802.02 bdl 3.47 1.82 2587 24.10 5.11 8.55 25.98 p1-b bdl 0.87 23.35 13.90 7717 646.81 8.22 20.89 9.29 p2-a 393.60 bdl 5.91 2.32 2595 76.55 4.37 2.55 8.63 p2-b 142.02 1.00 43.38 13.73 12025 930.67 10.31 16.04 7.95 p3 1049.71 bdl 2.45 7.41 2071 28.87 3.31 0.00 2.75 p4 bdl 0.37 24.47 2.11 5473 280.90 3.74 20.79 16.47 or p1-a 1683.36 bdl 27.94 3.27 3222 11.79 13.19 bdl 25.71 p1-b 1613.08 bdl 79.62 5.57 17529 73.59 29.30 bdl 44.00 p2-a 2038.51 bdl 31.70 1.50 3948 14.32 12.82 bdl 29.26 p2-b 1709.89 bdl 46.63 3.99 15739. 92.03 30.44 bdl 35.43 p3 229.10 bdl 0.00 bdl 1342.5 15.77 0.92 bdl 4.45 p4 1680.26 bdl 83.44 6.53 16406 67.00 24.47 bdl 34.85 res p1-a bdl bdl 1.77 bdl 930.1 bdl bdl bdl 0.92 p1-b 5598.19 bdl 36.75 16.07 11774 41.02 22.57 bdl 31.80 p2-a 139.03 bdl 2.15 bdl 431.2 bdl 0.77 bdl 1.57 p2-b 5503.41 bdl 38.48 13.79 13272 49.75 32.59 bdl 31.92 p3 bdl bdl 7.70 1.65 11387 81.49 5.92 bdl 4.25 p4 4545.32 bdl 32.83 12.01 10104 37.72 13.35 bdl 28.13